Bump version to v0.9.2

Signed-off-by: Russ Magee <rmagee@gmail.com>

.golangci.yml

@@ -0,0 +1,327 @@
+# This file contains all available configuration options
+# with their default values.
+
+# options for analysis running
+run:
+  # default concurrency is a available CPU number
+  concurrency: 4
+
+  # timeout for analysis, e.g. 30s, 5m, default is 1m
+  timeout: 1m
+
+  # exit code when at least one issue was found, default is 1
+  issues-exit-code: 1
+
+  # include test files or not, default is true
+  tests: true
+
+  # list of build tags, all linters use it. Default is empty list.
+  build-tags:
+    - mytag
+
+  # which dirs to skip: issues from them won't be reported;
+  # can use regexp here: generated.*, regexp is applied on full path;
+  # default value is empty list, but default dirs are skipped independently
+  # from this option's value (see skip-dirs-use-default).
+  skip-dirs:
+    - src/external_libs
+    - autogenerated_by_my_lib
+
+  # default is true. Enables skipping of directories:
+  #   vendor$, third_party$, testdata$, examples$, Godeps$, builtin$
+  skip-dirs-use-default: true
+
+  # which files to skip: they will be analyzed, but issues from them
+  # won't be reported. Default value is empty list, but there is
+  # no need to include all autogenerated files, we confidently recognize
+  # autogenerated files. If it's not please let us know.
+  skip-files:
+    - ".*\\.my\\.go$"
+    - lib/bad.go
+
+  # by default isn't set. If set we pass it to "go list -mod={option}". From "go help modules":
+  # If invoked with -mod=readonly, the go command is disallowed from the implicit
+  # automatic updating of go.mod described above. Instead, it fails when any changes
+  # to go.mod are needed. This setting is most useful to check that go.mod does
+  # not need updates, such as in a continuous integration and testing system.
+  # If invoked with -mod=vendor, the go command assumes that the vendor
+  # directory holds the correct copies of dependencies and ignores
+  # the dependency descriptions in go.mod.
+  #! modules-download-mode: readonly|release|vendor
+
+
+# output configuration options
+output:
+  # colored-line-number|line-number|json|tab|checkstyle|code-climate, default is "colored-line-number"
+  format: colored-line-number
+
+  # print lines of code with issue, default is true
+  print-issued-lines: true
+
+  # print linter name in the end of issue text, default is true
+  print-linter-name: true
+
+  # make issues output unique by line, default is true
+  uniq-by-line: true
+
+
+# all available settings of specific linters
+linters-settings:
+  dogsled:
+    # checks assignments with too many blank identifiers; default is 2
+    max-blank-identifiers: 2
+  dupl:
+    # tokens count to trigger issue, 150 by default
+    threshold: 100
+  errcheck:
+    # report about not checking of errors in type assetions: `a := b.(MyStruct)`;
+    # default is false: such cases aren't reported by default.
+    check-type-assertions: false
+
+    # report about assignment of errors to blank identifier: `num, _ := strconv.Atoi(numStr)`;
+    # default is false: such cases aren't reported by default.
+    check-blank: false
+
+    # [deprecated] comma-separated list of pairs of the form pkg:regex
+    # the regex is used to ignore names within pkg. (default "fmt:.*").
+    # see https://github.com/kisielk/errcheck#the-deprecated-method for details
+    ignore: fmt:.*,io/ioutil:^Read.*
+
+    # path to a file containing a list of functions to exclude from checking
+    # see https://github.com/kisielk/errcheck#excluding-functions for details
+    #!exclude: /path/to/file.txt
+  funlen:
+    lines: 60
+    statements: 40
+  gocognit:
+    # minimal code complexity to report, 30 by default (but we recommend 10-20)
+    min-complexity: 10
+  goconst:
+    # minimal length of string constant, 3 by default
+    min-len: 3
+    # minimal occurrences count to trigger, 3 by default
+    min-occurrences: 3
+  gocritic:
+    # Which checks should be enabled; can't be combined with 'disabled-checks';
+    # See https://go-critic.github.io/overview#checks-overview
+    # To check which checks are enabled run `GL_DEBUG=gocritic golangci-lint run`
+    # By default list of stable checks is used.
+    enabled-checks:
+      #!- rangeValCopy
+
+    # Which checks should be disabled; can't be combined with 'enabled-checks'; default is empty
+    disabled-checks:
+      - regexpMust
+
+    # Enable multiple checks by tags, run `GL_DEBUG=gocritic golangci-lint run` to see all tags and checks.
+    # Empty list by default. See https://github.com/go-critic/go-critic#usage -> section "Tags".
+    enabled-tags:
+      - performance
+
+    settings: # settings passed to gocritic
+      captLocal: # must be valid enabled check name
+        paramsOnly: true
+      rangeValCopy:
+        sizeThreshold: 32
+  gocyclo:
+    # minimal code complexity to report, 30 by default (but we recommend 10-20)
+    min-complexity: 10
+  godox:
+    # report any comments starting with keywords, this is useful for TODO or FIXME comments that
+    # might be left in the code accidentally and should be resolved before merging
+    keywords: # default keywords are TODO, BUG, and FIXME, these can be overwritten by this setting
+      - NOTE
+      - OPTIMIZE # marks code that should be optimized before merging
+      - HACK # marks hack-arounds that should be removed before merging
+  gofmt:
+    # simplify code: gofmt with `-s` option, true by default
+    simplify: true
+  goimports:
+    # put imports beginning with prefix after 3rd-party packages;
+    # it's a comma-separated list of prefixes
+    local-prefixes: github.com/org/project
+  golint:
+    # minimal confidence for issues, default is 0.8
+    min-confidence: 0.8
+  gomnd:
+    settings:
+      mnd:
+        # the list of enabled checks, see https://github.com/tommy-muehle/go-mnd/#checks for description.
+        checks: argument,case,condition,operation,return,assign
+  govet:
+    # report about shadowed variables
+    check-shadowing: true
+
+    # settings per analyzer
+    settings:
+      printf: # analyzer name, run `go tool vet help` to see all analyzers
+        funcs: # run `go tool vet help printf` to see available settings for `printf` analyzer
+          - (github.com/golangci/golangci-lint/pkg/logutils.Log).Infof
+          - (github.com/golangci/golangci-lint/pkg/logutils.Log).Warnf
+          - (github.com/golangci/golangci-lint/pkg/logutils.Log).Errorf
+          - (github.com/golangci/golangci-lint/pkg/logutils.Log).Fatalf
+
+    # enable or disable analyzers by name
+    enable:
+      - atomicalign
+    enable-all: false
+    disable:
+      - shadow
+    disable-all: false
+  depguard:
+    list-type: blacklist
+    include-go-root: false
+    packages:
+      - github.com/sirupsen/logrus
+    packages-with-error-message:
+      # specify an error message to output when a blacklisted package is used
+      - github.com/sirupsen/logrus: "logging is allowed only by logutils.Log"
+  lll:
+    # max line length, lines longer will be reported. Default is 120.
+    # '\t' is counted as 1 character by default, and can be changed with the tab-width option
+    line-length: 120
+    # tab width in spaces. Default to 1.
+    tab-width: 1
+  maligned:
+    # print struct with more effective memory layout or not, false by default
+    suggest-new: true
+  misspell:
+    # Correct spellings using locale preferences for US or UK.
+    # Default is to use a neutral variety of English.
+    # Setting locale to US will correct the British spelling of 'colour' to 'color'.
+    locale: US
+    ignore-words:
+      - someword
+  nakedret:
+    # make an issue if func has more lines of code than this setting and it has naked returns; default is 30
+    max-func-lines: 30
+  prealloc:
+    # XXX: we don't recommend using this linter before doing performance profiling.
+    # For most programs usage of prealloc will be a premature optimization.
+
+    # Report preallocation suggestions only on simple loops that have no returns/breaks/continues/gotos in them.
+    # True by default.
+    simple: true
+    range-loops: true # Report preallocation suggestions on range loops, true by default
+    for-loops: false # Report preallocation suggestions on for loops, false by default
+  rowserrcheck:
+    packages:
+      - github.com/jmoiron/sqlx
+  unparam:
+    # Inspect exported functions, default is false. Set to true if no external program/library imports your code.
+    # XXX: if you enable this setting, unparam will report a lot of false-positives in text editors:
+    # if it's called for subdir of a project it can't find external interfaces. All text editor integrations
+    # with golangci-lint call it on a directory with the changed file.
+    check-exported: false
+  unused:
+    # treat code as a program (not a library) and report unused exported identifiers; default is false.
+    # XXX: if you enable this setting, unused will report a lot of false-positives in text editors:
+    # if it's called for subdir of a project it can't find funcs usages. All text editor integrations
+    # with golangci-lint call it on a directory with the changed file.
+    check-exported: false
+  whitespace:
+    multi-if: false   # Enforces newlines (or comments) after every multi-line if statement
+    multi-func: false # Enforces newlines (or comments) after every multi-line function signature
+  wsl:
+    # If true append is only allowed to be cuddled if appending value is
+    # matching variables, fields or types on line above. Default is true.
+    strict-append: true
+    # Allow calls and assignments to be cuddled as long as the lines have any
+    # matching variables, fields or types. Default is true.
+    allow-assign-and-call: true
+    # Allow multiline assignments to be cuddled. Default is true.
+    allow-multiline-assign: true
+    # Allow declarations (var) to be cuddled.
+    allow-cuddle-declarations: false
+    # Allow trailing comments in ending of blocks
+    allow-trailing-comment: false
+    # Force newlines in end of case at this limit (0 = never).
+    force-case-trailing-whitespace: 0
+
+  # The custom section can be used to define linter plugins to be loaded at runtime. See README doc
+  #  for more info.
+  custom:
+    # Each custom linter should have a unique name.
+    #! example:
+    #!  # The path to the plugin *.so. Can be absolute or local. Required for each custom linter
+    #!  path: /path/to/example.so
+    #!  # The description of the linter. Optional, just for documentation purposes.
+    #!  description: This is an example usage of a plugin linter.
+    #!  # Intended to point to the repo location of the linter. Optional, just for documentation purposes.
+    #!  original-url: github.com/golangci/example-linter
+
+linters:
+  enable:
+    - megacheck
+    - govet
+  disable:
+    - maligned
+    - prealloc
+  disable-all: false
+  presets:
+    - bugs
+    - unused
+  fast: false
+
+
+issues:
+  # List of regexps of issue texts to exclude, empty list by default.
+  # But independently from this option we use default exclude patterns,
+  # it can be disabled by `exclude-use-default: false`. To list all
+  # excluded by default patterns execute `golangci-lint run --help`
+  exclude:
+    - abcdef
+
+  # Excluding configuration per-path, per-linter, per-text and per-source
+  exclude-rules:
+    # Exclude some linters from running on tests files.
+    - path: _test\.go
+      linters:
+        - gocyclo
+        - errcheck
+        - dupl
+        - gosec
+
+    # Exclude known linters from partially hard-vendored code,
+    # which is impossible to exclude via "nolint" comments.
+    - path: internal/hmac/
+      text: "weak cryptographic primitive"
+      linters:
+        - gosec
+
+    # Exclude some staticcheck messages
+    - linters:
+        - staticcheck
+      text: "SA9003:"
+
+    # Exclude lll issues for long lines with go:generate
+    - linters:
+        - lll
+      source: "^//go:generate "
+
+  # Independently from option `exclude` we use default exclude patterns,
+  # it can be disabled by this option. To list all
+  # excluded by default patterns execute `golangci-lint run --help`.
+  # Default value for this option is true.
+  exclude-use-default: false
+
+  # Maximum issues count per one linter. Set to 0 to disable. Default is 50.
+  max-issues-per-linter: 0
+
+  # Maximum count of issues with the same text. Set to 0 to disable. Default is 3.
+  max-same-issues: 0
+
+  # Show only new issues: if there are unstaged changes or untracked files,
+  # only those changes are analyzed, else only changes in HEAD~ are analyzed.
+  # It's a super-useful option for integration of golangci-lint into existing
+  # large codebase. It's not practical to fix all existing issues at the moment
+  # of integration: much better don't allow issues in new code.
+  # Default is false.
+  new: false
+
+  # Show only new issues created after git revision `REV`
+  #!new-from-rev: REV
+  #new-from-rev: HEAD^
+
+  # Show only new issues created in git patch with set file path.
+  #!new-from-patch: path/to/patch/file

CODE_OF_CONDUCT.md

@@ -0,0 +1,61 @@
+# Code of Merit (1.0-r1)
+
+1. The project creators, lead developers, core team, ("The Maintainers") constitute
+the managing members of the project and have final say in every decision
+of the project, technical or otherwise, including overruling previous decisions.
+There are no limitations to this decisional power.
+
+2. Contributions are an expected result of your membership on the project.
+Don't expect others to do your work or help you with your work forever. 
+
+3. All members have the same opportunities to seek any challenge they want
+within the project. 
+
+4. Authority or position in the project will be proportional
+to the accrued contribution. Seniority must be earned.
+
+5. Software is evolutive: the better implementations must supersede lesser
+implementations. Technical advantage is the primary evaluation metric.
+
+6. This is a space for technical prowess; topics outside of the project
+will not be tolerated.
+
+7. Non technical conflicts will be discussed in a separate space. Disruption
+of the project will not be allowed.
+
+8. Individual characteristics, including but not limited to,
+body, sex, sexual preference, race, language, religion, nationality,
+or political preferences are irrelevant in the scope of the project and
+will not be taken into account concerning your value or that of your contribution
+to the project.
+
+9. Discuss or debate the idea, not the person.
+
+10. There is no room for ambiguity: Ambiguity will be met with questioning;
+further ambiguity will be met with silence. It is the responsibility
+of the originator to provide requested context.
+
+11. If something is illegal outside the scope of the project, it is illegal
+in the scope of the project. This Code of Merit does not take precedence over
+governing law within the jurisdiction(s) of The Maintainers.
+
+    (11.a) If the algorithms implemented in this project (eg., cryptography)
+  are illegal or prohibited in your local jurisdiction, it is your personal
+  responsibility to consider how, or if, you should attempt to participate in this
+  project. The Maintainers disclaim all liability for others' actions and decisions
+  in this regard.
+
+12. This Code of Merit governs the technical procedures of the project not the 
+activities outside of it. 
+
+13. Participation on the project equates to agreement of this Code of Merit.
+
+14. No objectives beyond the stated objectives of this project are relevant
+to the project. Any intent to deviate the project from its original purpose
+of existence will constitute grounds for remedial action which may include
+expulsion from the project.
+
+This document is based upon the original Code of Merit version 1.0 (Dec 4 2018).
+(https://web.archive.org/web/20181204203029/http://code-of-merit.org/)
+
+Updated version (Mar 29 2020): https://codeofmerit.org/code/

LICENSE

@@ -1,7 +1,6 @@
 MIT License
 
-Copyright (c) 2017 - 2018 Omar Alejandro Herrera Reyna (core HerraduraKEx)
+Copyright (c) 2017 - 2019 Russell Magee (xs/xsd/xsnet/xspasswd)
-Copyright (c) 2017 - 2018 Russell Magee (hkexsh/hkexshd/hkexpasswd)
 
 Permission is hereby granted, free of charge, to any person obtaining a copy
 of this software and associated documentation files (the "Software"), to deal

LICENSE.gpl

@@ -1,674 +0,0 @@
-                    GNU GENERAL PUBLIC LICENSE
-                       Version 3, 29 June 2007
-
- Copyright (C) 2007 Free Software Foundation, Inc. <http://fsf.org/>
- Everyone is permitted to copy and distribute verbatim copies
- of this license document, but changing it is not allowed.
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-software and other kinds of works.
-
-  The licenses for most software and other practical works are designed
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-share and change all versions of a program--to make sure it remains free
-software for all its users.  We, the Free Software Foundation, use the
-GNU General Public License for most of our software; it applies also to
-any other work released this way by its authors.  You can apply it to
-your programs, too.
-
-  When we speak of free software, we are referring to freedom, not
-price.  Our General Public Licenses are designed to make sure that you
-have the freedom to distribute copies of free software (and charge for
-them if you wish), that you receive source code or can get it if you
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-<http://www.gnu.org/philosophy/why-not-lgpl.html>.

Makefile

@@ -1,23 +1,115 @@
-.PHONY: clean lib client server passwd
+VERSION := 0.9.2
+.PHONY: lint vis clean common client server passwd subpkgs install uninstall reinstall
 
-all: lib client server passwd
+## Tag version of binaries with build info wrt.
+## GO111MODULE(=on) and vendor/ setup vs. $GOPATH pkg builds
+############################################################
+ifeq ($(shell go env GOMOD),)
+MTAG=
+else
+MTAG="-m"
+endif
+
+ifneq ($(VENDOR),)
+GOBUILDOPTS :=-v -mod vendor
+VTAG = "-v"
+else
+GOBUILDOPTS=
+VTAG =
+endif
+############################################################
+
+GIT_COMMIT := $(shell git rev-list -1 HEAD)
+
+#ifeq ($(BUILDOPTS),)
+BUILDOPTS :=$(BUILDOPTS)"$(GOBUILDOPTS) -ldflags \"-X main.version=$(VERSION)$(MTAG)$(VTAG) -X main.gitCommit=$(GIT_COMMIT)\""
+#endif
+
+SUBPKGS = logger spinsult xsnet
+TOOLS = xs xsd
+SUBDIRS = $(LIBS) $(TOOLS)
+
+ifeq ($(GOOS),)
+	GOOS=$(shell go env GOOS)
+endif
+
+ifeq ($(GOOS),windows)
+ifeq ($(MSYSTEM),MSYS)
+WIN_MSYS=1
+endif
+endif
+
+
+INSTPREFIX = /usr/local
+
+all: common client server
 
 clean:
-	rm -f\
+	@echo "Make: $(MAKE)"
- hkexsh/hkexsh hkexsh/hkexsh.exe\
+	go clean .
- hkexshd/hkexshd hkexshd/hkexshd.exe\
+	for d in $(SUBDIRS); do\
- hkexpasswd/hkexpasswd hkexpasswd/hkexpasswd.exe
+	  $(MAKE) -C $$d clean;\
+	done
+
+subpkgs:
+	for d in $(SUBPKGS); do\
+	  $(MAKE) BUILDOPTS=$(BUILDOPTS) -C $$d all;\
+	done
+
+tools:
+	for d in $(TOOLS); do\
+	  $(MAKE) BUILDOPTS=$(BUILDOPTS) -C $$d all;\
+	done
 
 
-lib:
+common:
+	go build .
 	go install .
 
-client: lib
-	cd hkexsh; go build .; cd -
 
-server: lib
+client: common
-	cd hkexshd; go build .; cd -
+	$(MAKE) BUILDOPTS=$(BUILDOPTS) -C xs
 
-passwd: lib
-	cd hkexpasswd; go build .; cd -
 
+server: common
+ifeq ($(MSYSTEM),MSYS)
+	echo "Build of xsd server for Windows not yet supported"
+else
+	$(MAKE) BUILDOPTS=$(BUILDOPTS) -C xsd
+endif
+
+vis:
+	@which go-callvis >/dev/null 2>&1; \
+	stat=$$?; if [ $$stat -ne "0" ]; then \
+	  /bin/echo "go-callvis not found. Run go get https://github.com/TrueFurby/go-callvis to install."; \
+	else \
+	  $(MAKE) -C xs vis;\
+	  $(MAKE) -C xsd vis;\
+	fi
+
+lint:
+	$(MAKE) -C xsd lint
+	$(MAKE) -C xs lint
+
+reinstall: uninstall install
+
+install:
+	echo "WIN_MSYS:" $(WIN_MSYS)
+ifdef WIN_MSYS
+	cp xs/mintty_wrapper.sh $(INSTPREFIX)/bin/xs
+	cp xs/mintty_wrapper.sh $(INSTPREFIX)/bin/xc
+	cp xs/xs $(INSTPREFIX)/bin/_xs
+	cp xs/xs $(INSTPREFIX)/bin/_xc
+	echo "Install of xsd server for Windows not yet supported"
+else
+	cp xs/xs $(INSTPREFIX)/bin
+	cd $(INSTPREFIX)/bin && ln -s xs xc && cd -
+	cp xsd/xsd $(INSTPREFIX)/sbin
+endif
+
+uninstall:
+	rm -f $(INSTPREFIX)/bin/xs $(INSTPREFIX)/bin/xc \
+	$(INSTPREFIX)/bin/_xs $(INSTPREFIX)/bin/_xc
+ifndef $(WIN_MSYS)
+	rm -f $(INSTPREFIX)/sbin/xsd
+endif

README.md

@@ -1,68 +1,216 @@
-HKExSh
+[![GoDoc](https://godoc.org/blitter.com/go/xs?status.svg)](https://godoc.org/blitter.com/go/xs)
+
+# XS
 --
 
-'hkexsh' (HerraduraKEx shell) is a golang implementation of a simple
+XS (**X**perimental **S**hell) is a golang implementation of a simple remote shell client and
-remote shell client and server, similar in role to ssh, offering
+server, similar in role to ssh, offering encrypted interactive and non-interactive sessions (remote commands),
-encrypted interactive and non-interactive sessions. The client and server
+remote file copying and tunnels with optional traffic obfuscation ('chaffing').
-programs (hkexsh and hkexshd) use a mostly drop-in replacement for golang's
+
-standard golang/pkg/net facilities (net.Dial(), net.Listen(), net.Accept()
+It is stable to the point that I use it for day-to-day remote access in place of, and in preference to, ssh.
+
+***
+**NOTE: Due to the experimental nature of the KEX/KEM algorithms used, and the novelty of the overall codebase, this package SHOULD BE CONSIDERED EXTREMELY EXPERIMENTAL and USED WITH CAUTION. It DEFINITELY SHOULD NOT be used for any sensitive applications. USE AT YOUR OWN RISK. NEITHER WARRANTY NOR CLAIM OF FITNESS FOR PURPOSE IS EXPRESSED OR IMPLIED.**
+
+***
+
+The client and server programs (xs and xsd) use a mostly drop-in
+replacement for golang's standard golang/pkg/net facilities (net.Dial(), net.Listen(), net.Accept()
 and the net.Conn type), which automatically negotiate keying material for
-'secure' sockets using the experimental HerraduraKEx key exchange algorithm
+secure sockets using one of a selectable set of experimental key exchange (KEX) or
-first released at
+key encapsulation mechanisms (KEM).
-[Omar Elejandro Herrera Reyna's HerraduraKEx project](http://github.com/Caume/HerraduraKEx).
 
-One can simply replace calls to net.Dial() with hkex.Dial(), and likewise
+### Key Exchange
-net.Listen() with hkex.Listen(), to obtain connections (hkex.Conn) conforming
+Currently supported exchanges are:
-to the basic net.Conn interface. Upon Dial(), the HerraduraKEx key exchange
-is initiated (whereby client and server independently derive the same
-keying material).
 
-Above the hkex.Conn layer, the server and client apps in this repository
+* The HerraduraKEx key exchange algorithm first released at
-(server/hkexshd and client/hkexsh) negotiate session settings (cipher/hmac
+[Omar Elejandro Herrera Reyna's HerraduraKEx project](http://github.com/Caume/HerraduraKEx);
-algorithms, interactive/non-interactive, etc.) to be used for further
+* The KYBER IND-CCA-2 secure key encapsulation mechanism, [pq-crystals Kyber](https://pq-crystals.org/kyber/)  :: [Yawning/kyber golang implementation](https://git.schwanenlied.me/yawning/kyber)
-communication.
+* The NEWHOPE algorithm [newhopecrypto.org](https://www.newhopecrypto.org/) :: [Yawning/go-newhope golang implementation](https://git.schwanenlied.me/yawning/newhope)
+* The FrodoKEM algorithm [frodokem.org](https://frodokem.org/) :: Go version by [Eduardo E. S. Riccardi](https://github.com/kuking/go-frodokem)
 
-NOTE: Due to the experimental nature of the HerraduraKEx algorithm used to
+Currently supported session algorithms:
-derive crypto keying material, this algorithm and the demonstration remote
-shell client/server programs should be used with caution and should definitely
-NOT be used for any sensitive applications, or at the very least at one's
-own risk.
 
-As of this time (Jan 2018) no verdict by acknowledged 'crypto experts' as to
+[Encryption]
+* AES-256
+* Twofish-128
+* Blowfish-64
+* CryptMTv1 (64bit) (https://eprint.iacr.org/2005/165.pdf)
+* ChaCha20 (https://github.com/aead/chacha20)
+
+[HMAC]
+* HMAC-SHA256
+* HMAC-SHA512
+
+
+### Conn
+Calls to xsnet.Dial() and xsnet.Listen()/Accept() are generally the same as calls to the equivalents within the _net_ package; however upon connection a key exchange automatically occurs whereby client and server independently derive the same keying material, and all following traffic is secured by a symmetric encryption algorithm.
+
+### Session Negotiation
+Above the xsnet.Conn layer, the server and client apps in this repository (xsd/ and xs/ respectively) negotiate session settings (cipher/hmac algorithms, interactive/non-interactive mode, tunnel specifiers, etc.) to be used for communication.
+
+### Padding and Chaffing
+Packets are subject to padding (random size, randomly applied as prefix or postfix), and optionally the client and server channels can both send _chaff_ packets at random defineable intervals to help thwart analysis of session activity (applicable to interactive and non-interactive command sessions, file copies and tunnels).
+
+### Mux/Demux of Chaffing and Tunnel Data
+Chaffing and tunnels, if specified, are set up during initial client->server connection. Packets from the client local port(s) are sent through the main secured connection to the server's remote port(s), and vice versa, tagged with a chaff or tunnel specifier so that they can be discarded as chaff or de-multiplexed and delivered to the proper tunnel endpoints, respectively.
+
+### Accounts and Passwords
+Within the ```xspasswd/``` directory is a password-setting utility, ```xspasswd```, used if one wishes ```xs``` access to use separate credentials from those of the default (likely ssh) login method. In this mode, ```xsd``` uses its own password file distinct from the system /etc/passwd to authenticate clients, using standard bcrypt+salt storage. Activate this mode by invoking ```xsd``` with ```-s false```.
+
+HERRADURA KEX
+
+As of this time (Oct 2018) no verdict by acknowledged 'crypto experts' as to
 the level of security of the HerraduraKEx algorithm for purposes of session
 key exchange over an insecure channel has been rendered.
 It is hoped that experts in the field will analyze the algorithm and
 determine if it is indeed a suitable one for use in situations where
 Diffie-Hellman or other key exchange algorithms are currently utilized.
 
-Finally, within the hkexpasswd/ directory is a password-setting utility
+KYBER IND-CCA-2 KEM
-using its own user/password file distinct from the system /etc/passwd, which
-is used by the hkexshd server to authenticate clients.
 
-Dependencies:
+As of this time (Oct 2018) Kyber is one of the candidate algorithms submitted to the [NIST post-quantum cryptography project](https://csrc.nist.gov/Projects/Post-Quantum-Cryptography). The authors recommend using it in "... so-called hybrid mode in combination with established "pre-quantum" security; for example in combination with elliptic-curve Diffie-Hellman." THIS PROJECT DOES NOT DO THIS (in case you didn't notice yet, THIS PROJECT IS EXPERIMENTAL.)
---
+
-* Recent version of go (tested with go-1.9)
+### Dependencies:
+
+* Recent version of go (tested, at various times, with go-1.9 to go-1.12.4)
 * [github.com/mattn/go-isatty](http://github.com/mattn/go-isatty) //terminal tty detection
 * [github.com/kr/pty](http://github.com/kr/pty) //unix pty control (server pty connections)
 * [github.com/jameskeane/bcrypt](http://github.com/jameskeane/bcrypt) //password storage/auth
+* [blitter.com/go/goutmp](https://gogs.blitter.com/RLabs/goutmp) // wtmp/lastlog C bindings for user accounting
+* [https://git.schwanenlied.me/yawning/kyber](https://git.schwanenlied.me/yawning/kyber) // golang Kyber KEM
+* [https://git.schwanenlied.me/yawning/newhope](https://git.schwanenlied.me/yawning/newhope) // golang NEWHOPE,NEWHOPE-SIMPLE KEX
+* [blitter.com/go/mtwist](https://gogs.blitter.com/RLabs/mtwist) // 64-bit Mersenne Twister PRNG
+* [blitter.com/go/cryptmt](https://gogs.blitter.com/RLabs/cryptmt) // CryptMTv1 stream cipher
 
-Get source code
+### Get source code
---
-* $ go get -u github.com/Russtopia/hkexsh
-* $ go get github.com/mattn/go-isatty  ## only used by demos, not picked up by above go get -u?
 
-To build
+```
---
+$ go get -u blitter.com/go/xs
-* $ cd $GOPATH/src/github.com/Russtopia/hkexsh
+$ cd $GOPATH/src/blitter.com/go/xs
-* $ make clean all
+$ go build ./... # install all dependent go pkgs
+```
 
-To set accounts & passwords:
---
-* $ sudo echo "joebloggs:*:*:*" >/etc/hkexsh.passwd
-* $ sudo hkexpasswd/hkexpasswd -u joebloggs
-* $ <enter a password, enter again to confirm>
 
-Running Clent and Server. In separate shells:
+### To build
---
+
-* [A]$ sudo hkexshd/hkexshd &
+```
-* [B]$ hkexsh/hkexsh -u joebloggs
+$ cd $GOPATH/src/blitter.com/go/xs
+$ make clean all
+```
+
+### To install, uninstall, re-install
+
+```
+$ sudo make [install | uninstall | reinstall]
+```
+
+### To manage service (openrc init)
+
+An example init script (xsd.initrc) is provided. Consult your Linux distribution documentation for proper service/daemon installation. For openrc,
+
+```
+$ sudo cp xsd.initrc /etc/init.d/xsd
+$ sudo rc-config add xsd default
+```
+
+### To manage service (sysV init)
+
+An example init script (xsd.sysvrc) is provided. Consult your Linux distribution documentation for proper service/daemon installation. For sysV init,
+
+```
+$ sudo cp xsd.sysvrc /etc/init.d/xsd
+$ sudo sysv-rc-conf --level 2345 xsd on
+```
+
+The make system assumes installation in /usr/local/sbin (xsd, xspasswd) and /usr/local/bin (xs/xc symlink).
+
+```
+$ sudo rc-config [start | restart | stop] xsd
+```
+
+### To set accounts & passwords:
+
+```
+$ sudo touch /etc/xs.passwd
+$ sudo xspasswd/xspasswd -u joebloggs
+$ <enter a password, enter again to confirm>
+```
+
+### Testing Client and Server from $GOPATH dev tree (w/o 'make install')
+
+In separate shells A and B:
+```
+[A]$ cd xsd && sudo ./xsd &  # add -d for debugging
+```
+
+Interactive shell
+```
+[B]$ cd xs && ./xs joebloggs@host-or-ip # add -d for debugging
+```
+
+One-shot command
+```
+[B]$ cd xs && ./xs -x "ls /tmp" joebloggs@host-or-ip
+```
+
+WARNING WARNING WARNING: the -d debug flag will echo passwords to the log/console!
+Logging on Linux usually goes to /var/log/syslog and/or /var/log/debug, /var/log/daemon.log.
+
+NOTE if running client (xs) with -d, one will likely need to run 'reset' afterwards
+to fix up the shell tty afterwards, as stty echo may not be restored if client crashes
+or is interrupted.
+
+### Setting up an 'authtoken' for scripted (password-free) logins
+
+Use the -g option of xs to request a token from the remote server, which will return a
+hostname:token string. Place this string into $HOME/.xs_id to allow logins without
+entering a password (obviously, $HOME/.xs_id on both server and client for the user
+should *not* be world-readable.)
+
+### File Copying using xc
+
+xc is a symlink to xs, and the binary checks its own filename to determine whether
+it is being invoked in 'shell' or 'copy' mode. Refer to the '-h' output for differences in
+accepted options.
+
+General remote syntax is: user@server:[/]src-or-dest-path
+If no leading / is specified in src-or-dest-path, it is assumed to be relative to $HOME of the
+remote user. File operations are all performed as the remote user, so account permissions apply
+as expected.
+
+Local (client) to remote (server) copy:
+```
+$ xc fileA /some/where/fileB /some/where/else/dirC joebloggs@host-or-ip:remoteDir
+```
+
+Remote (server) to local (client) copy:
+```
+$ xc joebloggs@host-or-ip:/remoteDirOrFile /some/where/local/Dir
+```
+
+xc uses a 'tarpipe' to send file data over the encrypted channel. Use the -d flag on client or server to see the generated tar commands if you're curious.
+
+NOTE: Renaming while copying (eg., 'cp /foo/bar/fileA ./fileB') is NOT supported. Put another way, the destination (whether local or remote) must ALWAYS be a directory.
+
+If the 'pv' pipeview utility is available (http://www.ivarch.com/programs/pv.shtml) file transfer progress and bandwidth control will be available (suppress the former with the -q option, set the latter with -L &lt;bytes_per_second&gt;).
+
+### Tunnels
+
+Simple tunnels (client -> server, no reverse tunnels for now) are supported.
+
+Syntax: xs -T=&lt;tunspec&gt;{,&lt;tunspec&gt;...}
+.. where &lt;tunspec&gt; is &lt;localport:remoteport&gt;
+
+Example, tunnelling ssh through xs
+
+* [server side] ```$ sudo /usr/sbin/sshd -p 7002```
+* [client side, term A] ```$ xs -T=6002:7002 user@server```
+* [client side, term B] ```$ ssh user@localhost -p 6002```
+
+
+### Building for FreeBSD
+
+The Makefile(s) to build require GNU make (gmake).
+Please install and invoke build via:
+```$ gmake clean all```

TODO.txt

@@ -0,0 +1,38 @@
+HKExSh TODO Ideas
+--
+Chaff Improvements
+- Zipf or other distributions for chaff freq, packetsz
+- Mimicry of hand-typed traffic for chaff on interactive sessions
+- Client-input chaff file data (ie., Moby Dick)
+
+KEx: Look at ECIES: https://godoc.org/github.com/bitherhq/go-bither/crypto/ecies
+ThreeBears? BIKE?, NTRU?: https://www.safecrypto.eu/pqclounge/
+NIST Round 1 submissions:
+  https://csrc.nist.gov/projects/post-quantum-cryptography/round-1-submissions
+
+
+Architecture
+(DONE) - Move hkexnet components other than key exchange into a proper hkex package
+  (ie., hkexsh imports hkex) - hkex should be usable for other client/svr utils,
+  ala 'hkex-netcat')
+  (parts split out into hkexnet/*, hkexsession.go)
+(DONE) - Make KEx fully-pluggable: isolate all code to do with Herradura into a
+  KEx-neutral pkg so it can be swapped out for other methods (eg., DH etc.)
+(DONE - test branch) - Use system password db (/etc/{passwd,shadow})
+
+Features
+(DONE) - Support for hkcp (hkex-cp) - secure file copy protocol
+(DONE) - auth tokens to allow scripted hkexsh/hkexcp use
+(DONE) - tunnelling - multiple tunnel sessions co-existing w/shell sessions
+- non-interactive tunnel-only mode
+- reverse tunnels
+
+Alternate transports for hkexsh.Conn - HTTP-mimicking traffic, ICMP, ... ?
+(Whatever golang can support for net.Dial(), net.Accept(), io.Reader/Writer
+ should in principle be usable as substrate for hkex.Conn)
+
+Install
+(DONE - openrc) - init scripts for open-rc/init (and systemd, sigh)
+(DONE) - make install
+- common packages (yum/deb/portage)
+

auth.go

@@ -0,0 +1,227 @@
+package xs
+
+// Package xs - a secure terminal client/server written from scratch in Go
+//
+// Copyright (c) 2017-2020 Russell Magee
+// Licensed under the terms of the MIT license (see LICENSE.mit in this
+// distribution)
+//
+// golang implementation by Russ Magee (rmagee_at_gmail.com)
+
+// Authentication routines for the HKExSh
+
+import (
+	"bytes"
+	"encoding/csv"
+	"errors"
+	"fmt"
+	"io"
+	"io/ioutil"
+	"log"
+	"os"
+	"os/user"
+	"runtime"
+	"strings"
+
+	"github.com/jameskeane/bcrypt"
+	passlib "gopkg.in/hlandau/passlib.v1"
+)
+
+type AuthCtx struct {
+	reader     func(string) ([]byte, error)     // eg. ioutil.ReadFile()
+	userlookup func(string) (*user.User, error) // eg. os/user.Lookup()
+}
+
+func NewAuthCtx( /*reader func(string) ([]byte, error), userlookup func(string) (*user.User, error)*/ ) (ret *AuthCtx) {
+	ret = &AuthCtx{ioutil.ReadFile, user.Lookup}
+	return
+}
+
+// --------- System passwd/shadow auth routine(s) --------------
+
+// VerifyPass verifies a password against system standard shadow file
+// Note auxilliary fields for expiry policy are *not* inspected.
+func VerifyPass(ctx *AuthCtx, user, password string) (bool, error) {
+	if ctx.reader == nil {
+		ctx.reader = ioutil.ReadFile // dependency injection hides that this is required
+	}
+	passlib.UseDefaults(passlib.Defaults20180601)
+	var pwFileName string
+	if runtime.GOOS == "linux" {
+		pwFileName = "/etc/shadow"
+	} else if runtime.GOOS == "freebsd" {
+		pwFileName = "/etc/master.passwd"
+	} else {
+		pwFileName = "unsupported"
+	}
+	pwFileData, e := ctx.reader(pwFileName)
+	if e != nil {
+		return false, e
+	}
+	pwLines := strings.Split(string(pwFileData), "\n")
+	if len(pwLines) < 1 {
+		return false, errors.New("Empty shadow file!")
+	} else {
+		var line string
+		var hash string
+		var idx int
+		for idx = range pwLines {
+			line = pwLines[idx]
+			lFields := strings.Split(line, ":")
+			if lFields[0] == user {
+				hash = lFields[1]
+				break
+			}
+		}
+		if len(hash) == 0 {
+			return false, errors.New("nil hash!")
+		} else {
+			pe := passlib.VerifyNoUpgrade(password, hash)
+			if pe != nil {
+				return false, pe
+			}
+		}
+	}
+	return true, nil
+}
+
+// --------- End System passwd/shadow auth routine(s) ----------
+
+// ------------- xs-local passwd auth routine(s) ---------------
+
+// AuthUserByPasswd checks user login information using a password.
+// This checks /etc/xs.passwd for auth info, and system /etc/passwd
+// to cross-check the user actually exists.
+// nolint: gocyclo
+func AuthUserByPasswd(ctx *AuthCtx, username string, auth string, fname string) (valid bool, allowedCmds string) {
+	if ctx.reader == nil {
+		ctx.reader = ioutil.ReadFile // dependency injection hides that this is required
+	}
+	if ctx.userlookup == nil {
+		ctx.userlookup = user.Lookup // again for dependency injection as dep is now hidden
+	}
+	b, e := ctx.reader(fname) // nolint: gosec
+	if e != nil {
+		valid = false
+		log.Printf("ERROR: Cannot read %s!\n", fname)
+	}
+	r := csv.NewReader(bytes.NewReader(b))
+
+	r.Comma = ':'
+	r.Comment = '#'
+	r.FieldsPerRecord = 3 // username:salt:authCookie [TODO:disallowedCmdList (a,b,...)]
+	for {
+		record, err := r.Read()
+		if err == io.EOF {
+			// Use dummy entry if user not found
+			// (prevent user enumeration attack via obvious timing diff;
+			// ie., not attempting any auth at all)
+			record = []string{"$nosuchuser$",
+				"$2a$12$l0coBlRDNEJeQVl6GdEPbU",
+				"$2a$12$l0coBlRDNEJeQVl6GdEPbUC/xmuOANvqgmrMVum6S4i.EXPgnTXy6"}
+			username = "$nosuchuser$"
+			err = nil
+		}
+		if err != nil {
+			log.Fatal(err)
+		}
+
+		if username == record[0] {
+			tmp, err := bcrypt.Hash(auth, record[1])
+			if err != nil {
+				break
+			}
+			if tmp == record[2] && username != "$nosuchuser$" {
+				valid = true
+			}
+			break
+		}
+	}
+	// Security scrub
+	for i := range b {
+		b[i] = 0
+	}
+	r = nil
+	runtime.GC()
+
+	_, userErr := ctx.userlookup(username)
+	if userErr != nil {
+		valid = false
+	}
+	return
+}
+
+// ------------- End xs-local passwd auth routine(s) -----------
+
+// AuthUserByToken checks user login information against an auth token.
+// Auth tokens are stored in each user's $HOME/.xs_id and are requested
+// via the -g option.
+// The function also check system /etc/passwd to cross-check the user
+// actually exists.
+func AuthUserByToken(ctx *AuthCtx, username string, connhostname string, auth string) (valid bool) {
+	if ctx.reader == nil {
+		ctx.reader = ioutil.ReadFile // dependency injection hides that this is required
+	}
+	if ctx.userlookup == nil {
+		ctx.userlookup = user.Lookup // again for dependency injection as dep is now hidden
+	}
+
+	auth = strings.TrimSpace(auth)
+	u, ue := ctx.userlookup(username)
+	if ue != nil {
+		return false
+	}
+
+	b, e := ctx.reader(fmt.Sprintf("%s/.xs_id", u.HomeDir))
+	if e != nil {
+		log.Printf("INFO: Cannot read %s/.xs_id\n", u.HomeDir)
+		return false
+	}
+
+	r := csv.NewReader(bytes.NewReader(b))
+
+	r.Comma = ':'
+	r.Comment = '#'
+	r.FieldsPerRecord = 2 // connhost:authtoken
+	for {
+		record, err := r.Read()
+		if err == io.EOF {
+			return false
+		}
+		record[0] = strings.TrimSpace(record[0])
+		record[1] = strings.TrimSpace(record[1])
+		//fmt.Println("auth:", auth, "record:",
+		//	strings.Join([]string{record[0], record[1]}, ":"))
+
+		if (connhostname == record[0]) &&
+			(auth == strings.Join([]string{record[0], record[1]}, ":")) {
+			valid = true
+			break
+		}
+	}
+	_, userErr := ctx.userlookup(username)
+	if userErr != nil {
+		valid = false
+	}
+	return
+}
+
+func GetTool(tool string) (ret string) {
+	ret = "/bin/"+tool
+	_, err := os.Stat(ret)
+	if err == nil {
+		return ret
+	}
+	ret = "/usr/bin/"+tool
+	_, err = os.Stat(ret)
+	if err == nil {
+		return ret
+	}
+	ret = "/usr/local/bin/"+tool
+	_, err = os.Stat(ret)
+	if err == nil {
+		return ret
+	}
+	return ""
+}
+

auth_test.go

@@ -0,0 +1,212 @@
+package xs
+
+import (
+	"errors"
+	"fmt"
+	"os/user"
+	"strings"
+	"testing"
+)
+
+type userVerifs struct {
+	user   string
+	passwd string
+	good   bool
+}
+
+var (
+	dummyShadowA = `johndoe:$6$EeQlTtn/KXdSh6CW$UHbFuEw3UA0Jg9/GoPHxgWk6Ws31x3IjqsP22a9pVMOte0yQwX1.K34oI4FACu8GRg9DArJ5RyWUE9m98qwzZ1:18310:0:99999:7:::
+joebloggs:$6$F.0IXOrb0w0VJHG1$3O4PYyng7F3hlh42mbroEdQZvslybY5etPPiLMQJ1xosjABY.Q4xqAfyIfe03Du61ZjGQIt3nL0j12P9k1fsK/:18310:0:99999:7:::
+disableduser:!:18310::::::`
+
+	dummyAuthTokenFile = "hostA:abcdefg\nhostB:wxyz\n"
+
+	dummyXsPasswdFile = `#username:salt:authCookie
+bobdobbs:$2a$12$9vqGkFqikspe/2dTARqu1O:$2a$12$9vqGkFqikspe/2dTARqu1OuDKCQ/RYWsnaFjmi.HtmECRkxcZ.kBK
+notbob:$2a$12$cZpiYaq5U998cOkXzRKdyu:$2a$12$cZpiYaq5U998cOkXzRKdyuJ2FoEQyVLa3QkYdPQk74VXMoAzhvuP6
+`
+
+	testGoodUsers = []userVerifs{
+		{"johndoe", "testpass", true},
+		{"joebloggs", "testpass2", true},
+		{"johndoe", "badpass", false},
+	}
+
+	testXsPasswdUsers = []userVerifs{
+		{"bobdobbs", "praisebob", true},
+		{"notbob", "imposter", false},
+	}
+
+	userlookup_arg_u string
+	readfile_arg_f   string
+)
+
+func newMockAuthCtx(reader func(string) ([]byte, error), userlookup func(string) (*user.User, error)) (ret *AuthCtx) {
+	ret = &AuthCtx{reader, userlookup}
+	return
+}
+
+func _mock_user_Lookup(username string) (*user.User, error) {
+	username = userlookup_arg_u
+	if username == "baduser" {
+		return &user.User{}, errors.New("bad user")
+	}
+	urec := &user.User{Uid: "1000", Gid: "1000", Username: username, Name: "Full Name", HomeDir: "/home/user"}
+	fmt.Printf("  [mock user rec:%v]\n", urec)
+	return urec, nil
+}
+
+func _mock_ioutil_ReadFile(f string) ([]byte, error) {
+	f = readfile_arg_f
+	if f == "/etc/shadow" {
+		fmt.Println("  [mocking ReadFile(\"/etc/shadow\")]")
+		return []byte(dummyShadowA), nil
+	}
+	if f == "/etc/xs.passwd" {
+		fmt.Println("  [mocking ReadFile(\"/etc/xs.passwd\")]")
+		return []byte(dummyXsPasswdFile), nil
+	}
+	if strings.Contains(f, "/.xs_id") {
+		fmt.Println("  [mocking ReadFile(\".xs_id\")]")
+		return []byte(dummyAuthTokenFile), nil
+	}
+	return []byte{}, errors.New("no readfile_arg_f supplied")
+}
+
+func _mock_ioutil_ReadFileEmpty(f string) ([]byte, error) {
+	return []byte{}, nil
+}
+
+func _mock_ioutil_ReadFileHasError(f string) ([]byte, error) {
+	return []byte{}, errors.New("IO Error")
+}
+
+func TestVerifyPass(t *testing.T) {
+	readfile_arg_f = "/etc/shadow"
+	ctx := newMockAuthCtx(_mock_ioutil_ReadFile, nil)
+	for idx, rec := range testGoodUsers {
+		stat, e := VerifyPass(ctx, rec.user, rec.passwd)
+		if rec.good && (!stat || e != nil) {
+			t.Fatalf("failed %d\n", idx)
+		}
+	}
+}
+
+func TestVerifyPassFailsOnEmptyFile(t *testing.T) {
+	ctx := newMockAuthCtx(_mock_ioutil_ReadFileEmpty, nil)
+	stat, e := VerifyPass(ctx, "johndoe", "somepass")
+	if stat || (e == nil) {
+		t.Fatal("failed to fail w/empty file")
+	}
+}
+
+func TestVerifyPassFailsOnFileError(t *testing.T) {
+	ctx := newMockAuthCtx(_mock_ioutil_ReadFileEmpty, nil)
+	stat, e := VerifyPass(ctx, "johndoe", "somepass")
+	if stat || (e == nil) {
+		t.Fatal("failed to fail on ioutil.ReadFile error")
+	}
+}
+
+func TestVerifyPassFailsOnDisabledEntry(t *testing.T) {
+	ctx := newMockAuthCtx(_mock_ioutil_ReadFileEmpty, nil)
+	stat, e := VerifyPass(ctx, "disableduser", "!")
+	if stat || (e == nil) {
+		t.Fatal("failed to fail on disabled user entry")
+	}
+}
+
+////
+
+func TestAuthUserByTokenFailsOnMissingEntryForHost(t *testing.T) {
+	ctx := newMockAuthCtx(_mock_ioutil_ReadFile, _mock_user_Lookup)
+	stat := AuthUserByToken(ctx, "johndoe", "hostZ", "abcdefg")
+	if stat {
+		t.Fatal("failed to fail on missing/mismatched host entry")
+	}
+}
+
+func TestAuthUserByTokenFailsOnMissingEntryForUser(t *testing.T) {
+	ctx := newMockAuthCtx(_mock_ioutil_ReadFile, _mock_user_Lookup)
+	stat := AuthUserByToken(ctx, "unkuser", "hostA", "abcdefg")
+	if stat {
+		t.Fatal("failed to fail on wrong user")
+	}
+}
+
+func TestAuthUserByTokenFailsOnUserLookupFailure(t *testing.T) {
+	ctx := newMockAuthCtx(_mock_ioutil_ReadFile, _mock_user_Lookup)
+	userlookup_arg_u = "baduser"
+	stat := AuthUserByToken(ctx, "johndoe", "hostA", "abcdefg")
+	if stat {
+		t.Fatal("failed to fail with bad return from user.Lookup()")
+	}
+}
+
+func TestAuthUserByTokenFailsOnMismatchedTokenForUser(t *testing.T) {
+	ctx := newMockAuthCtx(_mock_ioutil_ReadFile, _mock_user_Lookup)
+	stat := AuthUserByToken(ctx, "johndoe", "hostA", "badtoken")
+	if stat {
+		t.Fatal("failed to fail with valid user, bad token")
+	}
+}
+
+func TestAuthUserByTokenSucceedsWithMatchedUserAndToken(t *testing.T) {
+	ctx := newMockAuthCtx(_mock_ioutil_ReadFile, _mock_user_Lookup)
+	userlookup_arg_u = "johndoe"
+	readfile_arg_f = "/.xs_id"
+	stat := AuthUserByToken(ctx, userlookup_arg_u, "hostA", "hostA:abcdefg")
+	if !stat {
+		t.Fatal("failed with valid user and token")
+	}
+}
+
+func TestAuthUserByPasswdFailsOnEmptyFile(t *testing.T) {
+	ctx := newMockAuthCtx(_mock_ioutil_ReadFileEmpty, _mock_user_Lookup)
+	userlookup_arg_u = "bobdobbs"
+	readfile_arg_f = "/etc/xs.passwd"
+	stat, _ := AuthUserByPasswd(ctx, userlookup_arg_u, "praisebob", readfile_arg_f)
+	if stat {
+		t.Fatal("failed to fail with missing xs.passwd file")
+	}
+}
+
+func TestAuthUserByPasswdFailsOnBadAuth(t *testing.T) {
+	ctx := newMockAuthCtx(_mock_ioutil_ReadFile, _mock_user_Lookup)
+	userlookup_arg_u = "bobdobbs"
+	readfile_arg_f = "/etc/xs.passwd"
+	stat, _ := AuthUserByPasswd(ctx, userlookup_arg_u, "wrongpass", readfile_arg_f)
+	if stat {
+		t.Fatal("failed to fail with valid user, incorrect passwd in xs.passwd file")
+	}
+}
+
+func TestAuthUserByPasswdFailsOnBadUser(t *testing.T) {
+	ctx := newMockAuthCtx(_mock_ioutil_ReadFile, _mock_user_Lookup)
+	userlookup_arg_u = "bobdobbs"
+	readfile_arg_f = "/etc/xs.passwd"
+	stat, _ := AuthUserByPasswd(ctx, userlookup_arg_u, "theotherbob", readfile_arg_f)
+	if stat {
+		t.Fatal("failed to fail on invalid user vs. xs.passwd file")
+	}
+}
+
+func TestAuthUserByPasswdPassesOnGoodAuth(t *testing.T) {
+	ctx := newMockAuthCtx(_mock_ioutil_ReadFile, _mock_user_Lookup)
+	userlookup_arg_u = "bobdobbs"
+	readfile_arg_f = "/etc/xs.passwd"
+	stat, _ := AuthUserByPasswd(ctx, userlookup_arg_u, "praisebob", readfile_arg_f)
+	if !stat {
+		t.Fatal("failed on valid user w/correct passwd in xs.passwd file")
+	}
+}
+
+func TestAuthUserByPasswdPassesOnOtherGoodAuth(t *testing.T) {
+	ctx := newMockAuthCtx(_mock_ioutil_ReadFile, _mock_user_Lookup)
+	userlookup_arg_u = "notbob"
+	readfile_arg_f = "/etc/xs.passwd"
+	stat, _ := AuthUserByPasswd(ctx, userlookup_arg_u, "imposter", readfile_arg_f)
+	if !stat {
+		t.Fatal("failed on valid user 2nd entry w/correct passwd in xs.passwd file")
+	}
+}

bacillus/ci_pushbuild.sh

@@ -0,0 +1,105 @@
+#!/bin/bash
+#
+## bacillus (https://gogs.blitter.com/Russtopia/bacillus) build/test CI script
+
+export GOPATH="${HOME}/go"
+export PATH=/usr/local/bin:/usr/bin:/usr/lib/ccache/bin:/bin:$GOPATH/bin
+export GO111MODULE=on
+# GOCACHE will be phased out in v1.12. [github.com/golang/go/issues/26809]
+export GOCACHE="${HOME}/.cache/go-build"
+
+echo "workdir: ${BACILLUS_WORKDIR}"
+mkdir -p "${BACILLUS_ARTFDIR}"
+
+echo "---"
+go env
+echo "---"
+echo "passed env:"
+env
+echo "---"
+
+cd ${REPO}
+branch=$(git for-each-ref --sort=-committerdate --format='%(refname)' | head -n 1)
+echo "Building most recent push on branch $branch"
+git checkout "$branch"
+ls
+
+############
+stage "Build"
+############
+make all
+
+############
+stage "UnitTests"
+############
+go test -v .
+
+############
+stage "Test(Authtoken)"
+############
+if [ -f ~/.xs_id ]; then
+  echo "Clearing test user $USER ~/.xs_id file ..."
+  mv ~/.xs_id ~/.xs_id.bak
+fi
+echo "Setting dummy authtoken in ~/.xs_id ..."
+echo "localhost:asdfasdfasdf" >~/.xs_id
+echo "Performing remote command on @localhost via authtoken login ..."
+tokentest=$(timeout 10 xs -x "echo -n FOO" @localhost)
+if [ "${tokentest}" != "FOO" ]; then
+  echo "AUTHTOKEN LOGIN FAILED"
+  exit 1
+else
+  echo "client cmd performed OK."
+  unset tokentest
+fi
+
+############
+stage "Test(S->C)"
+############
+echo "Testing secure copy from server -> client ..."
+tmpdir=$$
+mkdir -p /tmp/$tmpdir
+cd /tmp/$tmpdir
+xc @localhost:${BACILLUS_WORKDIR}/build/xs/cptest .
+echo -n "Integrity check on copied files (sha1sum) ..."
+sha1sum $(find cptest -type f | sort) >sc.sha1sum
+diff sc.sha1sum ${BACILLUS_WORKDIR}/build/xs/cptest.sha1sum
+stat=$?
+cd -
+
+rm -rf /tmp/$tmpdir
+if [ $stat -eq "0" ]; then
+  echo "OK."
+else
+  echo "FAILED!"
+  exit $stat
+fi
+
+############
+stage "Test(C->S)"
+############
+echo "TODO ..."
+
+if [ -f ~/.xs_id.bak ]; then
+  echo "Restoring test user $USER ~/.xs_id file ..."
+  mv ~/.xs_id.bak ~/.xs_id
+fi
+
+############
+stage "Lint"
+############
+make lint
+
+############
+stage "Artifacts"
+############
+echo -n "Creating tarfile ..."
+tar -cz --exclude=.git --exclude=cptest -f ${BACILLUS_ARTFDIR}/xs.tgz .
+
+############
+stage "Cleanup"
+############
+# nop
+
+echo
+echo "--Done--"

consts.go

@@ -0,0 +1,10 @@
+// Package xs - a secure terminal client/server written from scratch in Go
+//
+// Copyright (c) 2017-2020 Russell Magee
+// Licensed under the terms of the MIT license (see LICENSE.mit in this
+// distribution)
+//
+// golang implementation by Russ Magee (rmagee_at_gmail.com)
+package xs
+
+// common constants for the XS (Xperimental Shell)

cp.cmd

@@ -0,0 +1,12 @@
+## Template for copying files from local to remote site, destdir DEST:
+tar -cz -f - testdir/sub1/bar.txt | \
+  tar -xzv -C DEST --xform="s#.*/\(.*\)#\1#"
+
+# Note the --xform= option will strip leading path components from the file
+# on extraction (ie., throw away dirtree info when copying into remote DEST)
+#
+# Probably need to have a '-r' option ala 'scp -r' to control --xform=
+# (in the absence of --xform=.. above, files and dirs will all be extracted
+# to remote DEST preserving tree structure.)
+
+tar cf /dev/stdout ../*.txt | tar xf -

cptest.sha1sum

@@ -0,0 +1,6 @@
+306637b5c621892078ebadd9454a78820a000598  cptest/file16KB
+1a118dfff291352eb4aec02c34f4f957669460fc  cptest/file1KB
+f474d5da45890b7cb5b0ae84c8ade5abcb3b4474  cptest/file32KB
+03939175ceac92b9c6464d037a0243e22563c423  cptest/file6B
+da67c7698b25d94c0cc20284ba9d4008cdee201b  cptest/subdir/file32MB
+9da9888265371375b48c224b94a0b3132b7ddc41  cptest/subdir/file64MB

fixup-gv.sh

@@ -0,0 +1,9 @@
+#!/bin/bash
+
+inFile="${1/.go/}"
+visFile="${inFile}-vis.gv"
+
+#grep -o "\.[a-zA-Z_]*\$[0-9]*" "$inFile"-vis.gv | sort | uniq
+grep -o "#gv:.*" "$inFile.go" | cut -f2 -d: | \
+while read -r expr; do sed -i ${expr} "${visFile}"; done
+

go.mod

@@ -0,0 +1,30 @@
+module blitter.com/go/xs
+
+go 1.12
+
+require (
+	blitter.com/go/cryptmt v1.0.2
+	blitter.com/go/goutmp v1.0.5
+	blitter.com/go/herradurakex v1.0.0
+	blitter.com/go/kyber v0.0.0-20200130200857-6f2021cb88d9
+	blitter.com/go/mtwist v1.0.1 // indirect
+	blitter.com/go/newhope v0.0.0-20200130200750-192fc08a8aae
+	github.com/aead/chacha20 v0.0.0-20180709150244-8b13a72661da
+	github.com/creack/pty v1.1.11
+	github.com/jameskeane/bcrypt v0.0.0-20120420032655-c3cd44c1e20f
+	github.com/klauspost/reedsolomon v1.9.9 // indirect
+	github.com/kuking/go-frodokem v1.0.1
+	github.com/mattn/go-isatty v0.0.12
+	github.com/mmcloughlin/avo v0.0.0-20200523190732-4439b6b2c061 // indirect
+	github.com/pkg/errors v0.9.1 // indirect
+	github.com/templexxx/cpufeat v0.0.0-20180724012125-cef66df7f161 // indirect
+	github.com/templexxx/xor v0.0.0-20191217153810-f85b25db303b // indirect
+	github.com/tjfoc/gmsm v1.3.1 // indirect
+	github.com/xtaci/kcp-go v5.4.20+incompatible
+	github.com/xtaci/lossyconn v0.0.0-20200209145036-adba10fffc37 // indirect
+	golang.org/x/crypto v0.0.0-20200510223506-06a226fb4e37
+	golang.org/x/sys v0.0.0-20200523222454-059865788121
+	gopkg.in/hlandau/easymetric.v1 v1.0.0 // indirect
+	gopkg.in/hlandau/measurable.v1 v1.0.1 // indirect
+	gopkg.in/hlandau/passlib.v1 v1.0.10
+)

go.sum

@@ -0,0 +1,94 @@
+blitter.com/go/chacha20 v0.0.0-20200130200441-214e4085f54c h1:LcnFFg6MCIJHf26P7eOUST45fNLHJI5erq0gWZaDLCo=
+blitter.com/go/chacha20 v0.0.0-20200130200441-214e4085f54c/go.mod h1:EMJtRcf22WCtHGiXCw+NB/Sb/PYcXtUgUql6LDEwyXo=
+blitter.com/go/cryptmt v1.0.2 h1:ZcLhQk7onUssXyQwG3GdXDXctCVnNL+b7aFuvwOdKXc=
+blitter.com/go/cryptmt v1.0.2/go.mod h1:tdME2J3O4agaDAYIYNQzzuB28yVGnPSMmV3a/ucSU84=
+blitter.com/go/goutmp v1.0.5 h1:isP6bxSs1O06Oy7wB8u4y5SgLr22txfjg/gjG4qn0Og=
+blitter.com/go/goutmp v1.0.5/go.mod h1:gtlbjC8xGzMk/Cf0BpnVltSa3awOqJ+B5WAxVptTMxk=
+blitter.com/go/herradurakex v1.0.0 h1:6XaxY+JLT1HUWPF0gYJnjX3pVjrw4YhYZEzZ1U0wkyc=
+blitter.com/go/herradurakex v1.0.0/go.mod h1:m3+vYZX+2dDjdo+n/HDnXEYJX9pwmNeQLgAfJM8mtxw=
+blitter.com/go/kyber v0.0.0-20200130200857-6f2021cb88d9 h1:D45AnrNphtvczBXRp5JQicZRTgaK/Is5bgPDDvRKhTc=
+blitter.com/go/kyber v0.0.0-20200130200857-6f2021cb88d9/go.mod h1:SK6QfGG72lIfKW1Td0wH7f0wwN5nSIhV3K+wvzGNjrw=
+blitter.com/go/mtwist v1.0.1 h1:PxmoWexfMpLmc8neHP/PcRc3s17ct7iz4d5W/qJVt04=
+blitter.com/go/mtwist v1.0.1/go.mod h1:aU82Nx8+b1v8oZRNqImfEDzDTPim81rY0ACKAIclV18=
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grml.yaml

@@ -0,0 +1,44 @@
+env:
+  project: xs
+  version: 0.8.0
+  buildDir: build/
+  docDir: doc/
+  releaseDir: ${project}-${version}/
+
+options:
+  debug: false
+  breakfast:
+    - sausage & spam
+    - spam, egg, sausage & spam
+    - spam, spam, beans, spam & spam
+
+commands:
+  release:
+    help: do full rebuild, docgen and store artifacts in ${releaseDir}
+    deps:
+      - vis
+      - app
+    exec: |
+      echo "TODO: cp binary and docs to ${releaseDir}"
+
+  install:
+    help: install binaries (root)
+    deps:
+      - app
+    as-root: true
+    exec: |
+      make reinstall
+
+  vis:
+    help: generate graphviz (via go-callvis)
+    deps:
+      - app
+    exec: |
+      make vis
+
+  app:
+    aliases: [ build ]
+    help: build the xs tools
+    exec: |
+      make clean
+      make all

herradurakex.go

@@ -1,169 +0,0 @@
-// Package hkexsh - socket lib conforming to
-// golang.org/pkg/net Conn interface, with
-// experimental key exchange algorithm by
-// Omar Alejandro Herrera Reyna.
-//
-// (https://github.com/Caume/HerraduraKEx)
-//
-// The core HerraduraKEx algorithm is dual-licensed
-// by the author (Omar Alejandro Herrera Reyna)
-// under GPL3 and MIT licenses.
-// See LICENSE.gpl and LICENSE.mit in this distribution
-//
-// Copyright (c) 2017-2018 Russell Magee
-// Licensed under the terms of the MIT license (see LICENSE.mit in this
-// distribution)
-//
-// golang implementation by Russ Magee (rmagee_at_gmail.com)
-package hkexsh
-
-/*  Herradura - a Key exchange scheme in the style of Diffie-Hellman Key Exchange.
-    Copyright (C) 2017 Omar Alejandro Herrera Reyna
-
-    This program is free software: you can redistribute it and/or modify
-    it under the terms of the GNU General Public License as published by
-    the Free Software Foundation, either version 3 of the License, or
-    (at your option) any later version.
-
-    This program is distributed in the hope that it will be useful,
-    but WITHOUT ANY WARRANTY; without even the implied warranty of
-    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-    GNU General Public License for more details.
-
-    You should have received a copy of the GNU General Public License
-    along with this program.  If not, see <https://www.gnu.org/licenses/>.
-
-    golang implementation by Russ Magee (rmagee_at_gmail.com) */
-
-/* This is the core KEx algorithm. For client/server net support code,
-See hkexnet.go for a golang/pkg/net for the compatible Conn interface
-using this to transparently negotiate keys and secure a network channel. */
-
-import (
-	"fmt"
-	"math/big"
-	"math/rand"
-	"time"
-)
-
-// HerraduraKEx holds the session state for a key exchange.
-type HerraduraKEx struct {
-	intSz, pubSz int
-	randctx      *rand.Rand
-	a            *big.Int
-	b            *big.Int
-	d, PeerD     *big.Int
-	fa           *big.Int
-}
-
-// New returns a HerraduraKEx struct.
-//
-//   i - internal (private) random nonce
-//   p - public (exchanged) random nonce (typically 1/4 bitsize of i)
-//
-//   If i or p are passed as zero, they will default to 256 and 64,
-//   respectively.
-func New(i int, p int) (h *HerraduraKEx) {
-	h = new(HerraduraKEx)
-
-	if i == 0 {
-		i = 256
-	}
-	if p == 0 {
-		p = 64
-	}
-
-	h.intSz = i
-	h.pubSz = p
-
-	h.seed()
-	h.a = h.rand()
-	h.b = h.rand()
-
-	h.d = h.fscxRevolve(h.a, h.b, h.pubSz)
-	return h
-}
-
-func (h *HerraduraKEx) seed() {
-	r := rand.New(rand.NewSource(time.Now().UnixNano()))
-	h.randctx = r
-}
-
-func (h *HerraduraKEx) rand() (v *big.Int) {
-	v = big.NewInt(0)
-	v.Rand(h.randctx, h.getMax())
-	return v
-}
-
-// getMax returns the max value for an n-bit big.Int
-func (h *HerraduraKEx) getMax() (n *big.Int) {
-	n = big.NewInt(0)
-	var max big.Int
-
-	for i := 0; i < h.intSz; i++ {
-		max.SetBit(n, i, 1)
-	}
-	n = &max
-	return n
-}
-
-func (h *HerraduraKEx) bitX(x *big.Int, pos int) (ret int64) {
-	if pos < 0 {
-		pos = h.intSz - pos
-	}
-
-	if pos == 0 {
-		ret = int64(x.Bit(1) ^ x.Bit(0) ^ x.Bit(h.intSz-1))
-	} else if pos == h.intSz-1 {
-		ret = int64(x.Bit(0) ^ x.Bit(pos) ^ x.Bit(pos-1))
-	} else {
-		ret = int64(x.Bit((pos+1)%h.intSz) ^ x.Bit(pos) ^ x.Bit(pos-1))
-	}
-	return ret
-}
-
-func (h *HerraduraKEx) bit(up, down *big.Int, posU, posD int) (ret *big.Int) {
-	return big.NewInt(h.bitX(up, posU) ^ h.bitX(down, posD))
-}
-
-func (h *HerraduraKEx) fscx(up, down *big.Int) (result *big.Int) {
-	result = big.NewInt(0)
-
-	for count := 0; count < h.intSz; count++ {
-		result.Lsh(result, 1)
-		result.Add(result, h.bit(up, down, count, count))
-	}
-	return result
-}
-
-// This is the iteration function using the result of the previous iteration
-// as the first parameter and the second parameter of the first iteration.
-func (h *HerraduraKEx) fscxRevolve(x, y *big.Int, passes int) (result *big.Int) {
-	result = x
-	for count := 0; count < passes; count++ {
-		result = h.fscx(result, y)
-	}
-	return result
-}
-
-// D returns the D (FSCX Revolved) value, input to generate FA
-// (the value for peer KEx)
-func (h *HerraduraKEx) D() *big.Int {
-	return h.d
-}
-
-// FA returns the FA value, which must be sent to peer for KEx.
-func (h *HerraduraKEx) FA() {
-	h.fa = h.fscxRevolve(h.PeerD, h.b, h.intSz-h.pubSz)
-	h.fa.Xor(h.fa, h.a)
-}
-
-// Output HerraduraKEx type value as a string. Implements Stringer interface.
-func (h *HerraduraKEx) String() string {
-	return fmt.Sprintf("s:%d p:%d\na:%s\nb:%s\nd:->%s\n<-PeerD:%s\nfa:%s",
-		h.intSz, h.pubSz,
-		h.a.Text(16), h.b.Text(16),
-		h.d.Text(16),
-		h.PeerD.Text(16),
-		h.fa.Text(16))
-}

hkexauth.go

@@ -1,55 +0,0 @@
-// Authentication routines for the HKExSh
-//
-// Copyright (c) 2017-2018 Russell Magee
-// Licensed under the terms of the MIT license (see LICENSE.mit in this
-// distribution)
-//
-// golang implementation by Russ Magee (rmagee_at_gmail.com)
-
-package hkexsh
-
-import (
-	"bytes"
-	"encoding/csv"
-	"io"
-	"io/ioutil"
-	"log"
-	"runtime"
-
-	"github.com/jameskeane/bcrypt"
-)
-
-func AuthUser(username string, auth string, fname string) (valid bool, allowedCmds string) {
-	b, e := ioutil.ReadFile(fname)
-	if e != nil {
-		valid = false
-		log.Println("ERROR: Cannot read hkexsh.passwd file!")
-		log.Fatal(e)
-	}
-	r := csv.NewReader(bytes.NewReader(b))
-
-	b = nil
-	runtime.GC() // Paranoia and prob. not effective; kill authFile in b[]
-
-	r.Comma = ':'
-	r.Comment = '#'
-	r.FieldsPerRecord = 4 // username:salt:authCookie:disallowedCmdList (a,b,...)
-	for {
-		record, err := r.Read()
-		if err == io.EOF {
-			break
-		}
-		if err != nil {
-			log.Fatal(err)
-		}
-
-		if username == record[0] {
-			tmp, _ := bcrypt.Hash(auth, record[1])
-			if tmp == record[2] {
-				valid = true
-			}
-			break
-		}
-	}
-	return
-}

hkexnet.go

@@ -1,473 +0,0 @@
-// hkexnet.go - net.Conn compatible channel setup with encrypted/HMAC
-// negotiation
-
-// Copyright (c) 2017-2018 Russell Magee
-// Licensed under the terms of the MIT license (see LICENSE.mit in this
-// distribution)
-//
-// golang implementation by Russ Magee (rmagee_at_gmail.com)
-
-package hkexsh
-
-// Implementation of HKEx-wrapped versions of the golang standard
-// net package interfaces, allowing clients and servers to simply replace
-// 'net.Dial' and 'net.Listen' with 'hkex.Dial' and 'hkex.Listen'.
-import (
-	"bytes"
-	"crypto/cipher"
-	"encoding/binary"
-	"encoding/hex"
-	"errors"
-	"fmt"
-	"hash"
-	"io"
-	"log"
-	"math/big"
-	"net"
-	"strings"
-	"time"
-)
-
-const (
-	CSONone        = iota // No error, normal packet
-	CSOHmacInvalid        // HMAC mismatch detected on remote end
-	CSOTermSize           // set term size (rows:cols)
-	CSOChaff              // Dummy packet, do not pass beyond decryption
-)
-
-/*---------------------------------------------------------------------*/
-
-type WinSize struct {
-	Rows uint16
-	Cols uint16
-}
-
-// Conn is a HKex connection - a drop-in replacement for net.Conn
-type Conn struct {
-	c          net.Conn // which also implements io.Reader, io.Writer, ...
-	h          *HerraduraKEx
-	cipheropts uint32 // post-KEx cipher/hmac options
-	opts       uint32 // post-KEx protocol options (caller-defined)
-	WinCh      chan WinSize
-	Rows       uint16
-	Cols       uint16
-	r          cipher.Stream //read cipherStream
-	rm         hash.Hash
-	w          cipher.Stream //write cipherStream
-	wm         hash.Hash
-	dBuf       *bytes.Buffer //decrypt buffer for Read()
-}
-
-// ConnOpts returns the cipher/hmac options value, which is sent to the
-// peer but is not itself part of the KEx.
-//
-// (Used for protocol-level negotiations after KEx such as
-// cipher/HMAC algorithm options etc.)
-func (c Conn) ConnOpts() uint32 {
-	return c.cipheropts
-}
-
-// SetConnOpts sets the cipher/hmac options value, which is sent to the
-// peer as part of KEx but not part of the KEx itself.
-//
-// opts - bitfields for cipher and hmac alg. to use after KEx
-func (c *Conn) SetConnOpts(copts uint32) {
-	c.cipheropts = copts
-}
-
-// Opts returns the protocol options value, which is sent to the peer
-// but is not itself part of the KEx or connection (cipher/hmac) setup.
-//
-// Consumers of this lib may use this for protocol-level options not part
-// of the KEx or encryption info used by the connection.
-func (c Conn) Opts() uint32 {
-	return c.opts
-}
-
-// SetOpts sets the protocol options value, which is sent to the peer
-// but is not itself part of the KEx or connection (cipher/hmac) setup.
-//
-// Consumers of this lib may use this for protocol-level options not part
-// of the KEx of encryption info used by the connection.
-//
-// opts - a uint32, caller-defined
-func (c *Conn) SetOpts(opts uint32) {
-	c.opts = opts
-}
-
-func (c *Conn) applyConnExtensions(extensions ...string) {
-	for _, s := range extensions {
-		switch s {
-		case "C_AES_256":
-			log.Println("[extension arg = C_AES_256]")
-			c.cipheropts &= (0xFFFFFF00)
-			c.cipheropts |= CAlgAES256
-			break
-		case "C_TWOFISH_128":
-			log.Println("[extension arg = C_TWOFISH_128]")
-			c.cipheropts &= (0xFFFFFF00)
-			c.cipheropts |= CAlgTwofish128
-			break
-		case "C_BLOWFISH_64":
-			log.Println("[extension arg = C_BLOWFISH_64]")
-			c.cipheropts &= (0xFFFFFF00)
-			c.cipheropts |= CAlgBlowfish64
-			break
-		case "H_SHA256":
-			log.Println("[extension arg = H_SHA256]")
-			c.cipheropts &= (0xFFFF00FF)
-			c.cipheropts |= (HmacSHA256 << 8)
-			break
-		default:
-			log.Printf("[Dial ext \"%s\" ignored]\n", s)
-			break
-		}
-	}
-}
-
-// Dial as net.Dial(), but with implicit HKEx PeerD read on connect
-//   Can be called like net.Dial(), defaulting to C_AES_256/H_SHA256,
-//   or additional option arguments can be passed amongst the following:
-//
-//   "C_AES_256" | "C_TWOFISH_128"
-//
-//   "H_SHA256"
-func Dial(protocol string, ipport string, extensions ...string) (hc *Conn, err error) {
-	// Open raw Conn c
-	c, err := net.Dial(protocol, ipport)
-	if err != nil {
-		return nil, err
-	}
-	// Init hkexnet.Conn hc over net.Conn c
-	hc = &Conn{c: c, h: New(0, 0), dBuf: new(bytes.Buffer)}
-	hc.applyConnExtensions(extensions...)
-
-	// Send hkexnet.Conn parameters to remote side
-	// d is value for Herradura key exchange
-	fmt.Fprintf(c, "0x%s\n%08x:%08x\n", hc.h.d.Text(16),
-		hc.cipheropts, hc.opts)
-
-	d := big.NewInt(0)
-	_, err = fmt.Fscanln(c, d)
-	if err != nil {
-		return nil, err
-	}
-	_, err = fmt.Fscanf(c, "%08x:%08x\n",
-		&hc.cipheropts, &hc.opts)
-	if err != nil {
-		return nil, err
-	}
-
-	hc.h.PeerD = d
-	log.Printf("** D:%s\n", hc.h.d.Text(16))
-	log.Printf("**(c)** peerD:%s\n", hc.h.PeerD.Text(16))
-	hc.h.FA()
-	log.Printf("**(c)** FA:%s\n", hc.h.fa)
-
-	hc.r, hc.rm, err = hc.getStream(hc.h.fa)
-	hc.w, hc.wm, err = hc.getStream(hc.h.fa)
-	return
-}
-
-// Close a hkex.Conn
-func (c Conn) Close() (err error) {
-	err = c.c.Close()
-	log.Println("[Conn Closing]")
-	return
-}
-
-// LocalAddr returns the local network address.
-func (c Conn) LocalAddr() net.Addr {
-	return c.c.LocalAddr()
-}
-
-// RemoteAddr returns the remote network address.
-func (c Conn) RemoteAddr() net.Addr {
-	return c.c.RemoteAddr()
-}
-
-// SetDeadline sets the read and write deadlines associated
-// with the connection. It is equivalent to calling both
-// SetReadDeadline and SetWriteDeadline.
-//
-// A deadline is an absolute time after which I/O operations
-// fail with a timeout (see type Error) instead of
-// blocking. The deadline applies to all future and pending
-// I/O, not just the immediately following call to Read or
-// Write. After a deadline has been exceeded, the connection
-// can be refreshed by setting a deadline in the future.
-//
-// An idle timeout can be implemented by repeatedly extending
-// the deadline after successful Read or Write calls.
-//
-// A zero value for t means I/O operations will not time out.
-func (c Conn) SetDeadline(t time.Time) error {
-	return c.SetDeadline(t)
-}
-
-// SetWriteDeadline sets the deadline for future Write calls
-// and any currently-blocked Write call.
-// Even if write times out, it may return n > 0, indicating that
-// some of the data was successfully written.
-// A zero value for t means Write will not time out.
-func (c Conn) SetWriteDeadline(t time.Time) error {
-	return c.SetWriteDeadline(t)
-}
-
-// SetReadDeadline sets the deadline for future Read calls
-// and any currently-blocked Read call.
-// A zero value for t means Read will not time out.
-func (c Conn) SetReadDeadline(t time.Time) error {
-	return c.SetReadDeadline(t)
-}
-
-/*---------------------------------------------------------------------*/
-
-// HKExListener is a Listener conforming to net.Listener
-//
-// See go doc net.Listener
-type HKExListener struct {
-	l net.Listener
-}
-
-// Listen for a connection
-//
-// See go doc net.Listen
-func Listen(protocol string, ipport string) (hl HKExListener, e error) {
-	l, err := net.Listen(protocol, ipport)
-	if err != nil {
-		return HKExListener{nil}, err
-	}
-	log.Println("[Listening]")
-	hl.l = l
-	return
-}
-
-// Close a hkex Listener - closes the Listener.
-// Any blocked Accept operations will be unblocked and return errors.
-//
-// See go doc net.Listener.Close
-func (hl HKExListener) Close() error {
-	log.Println("[Listener Closed]")
-	return hl.l.Close()
-}
-
-// Addr returns a the listener's network address.
-//
-// See go doc net.Listener.Addr
-func (hl HKExListener) Addr() net.Addr {
-	return hl.l.Addr()
-}
-
-// Accept a client connection, conforming to net.Listener.Accept()
-//
-// See go doc net.Listener.Accept
-func (hl HKExListener) Accept() (hc Conn, err error) {
-	// Open raw Conn c
-	c, err := hl.l.Accept()
-	if err != nil {
-		return Conn{c: nil, h: nil, cipheropts: 0, opts: 0,
-			r: nil, w: nil}, err
-	}
-	log.Println("[Accepted]")
-
-	hc = Conn{c: c, h: New(0, 0), WinCh: make(chan WinSize, 1),
-		dBuf: new(bytes.Buffer)}
-
-	// Read in hkexnet.Conn parameters over raw Conn c
-	// d is value for Herradura key exchange
-	d := big.NewInt(0)
-	_, err = fmt.Fscanln(c, d)
-	log.Printf("[Got d:%v]", d)
-	if err != nil {
-		return hc, err
-	}
-	_, err = fmt.Fscanf(c, "%08x:%08x\n",
-		&hc.cipheropts, &hc.opts)
-	log.Printf("[Got cipheropts, opts:%v, %v]", hc.cipheropts, hc.opts)
-	if err != nil {
-		return hc, err
-	}
-	hc.h.PeerD = d
-	log.Printf("** D:%s\n", hc.h.d.Text(16))
-	log.Printf("**(s)** peerD:%s\n", hc.h.PeerD.Text(16))
-	hc.h.FA()
-	log.Printf("**(s)** FA:%s\n", hc.h.fa)
-
-	fmt.Fprintf(c, "0x%s\n%08x:%08x\n", hc.h.d.Text(16),
-		hc.cipheropts, hc.opts)
-
-	hc.r, hc.rm, err = hc.getStream(hc.h.fa)
-	hc.w, hc.wm, err = hc.getStream(hc.h.fa)
-	return
-}
-
-/*---------------------------------------------------------------------*/
-
-// Read into a byte slice
-//
-// See go doc io.Reader
-func (c Conn) Read(b []byte) (n int, err error) {
-	//log.Printf("[Decrypting...]\r\n")
-	log.Printf("Read() requests %d bytes\n", len(b))
-
-	for {
-		//log.Printf("c.dBuf.Len(): %d\n", c.dBuf.Len())
-		if c.dBuf.Len() > 0 /* len(b) */ {
-			break
-		}
-
-		var ctrlStatOp uint8
-		var hmacIn [4]uint8
-		var payloadLen uint32
-
-		// Read ctrl/status opcode (CSOHmacInvalid on hmac mismatch)
-		err = binary.Read(c.c, binary.BigEndian, &ctrlStatOp)
-		log.Printf("[ctrlStatOp: %v]\n", ctrlStatOp)
-		if ctrlStatOp == CSOHmacInvalid {
-			// Other side indicated channel tampering, close channel
-			c.Close()
-			return 1, errors.New("** ALERT - remote end detected HMAC mismatch - possible channel tampering **")
-		}
-
-		// Read the hmac and payload len first
-		err = binary.Read(c.c, binary.BigEndian, &hmacIn)
-		// Normal client 'exit' from interactive session will cause
-		// (on server side) err.Error() == "<iface/addr info ...>: use of closed network connection"
-		if err != nil {
-			if !strings.HasSuffix(err.Error(), "use of closed network connection") {
-				log.Println("unexpected Read() err:", err)
-			} else {
-				log.Println("[Client hung up]")
-			}
-			return 0, err
-		}
-
-		err = binary.Read(c.c, binary.BigEndian, &payloadLen)
-		if err != nil {
-			if err.Error() != "EOF" {
-				panic(err)
-				// Cannot just return 0, err here - client won't hang up properly
-				// when 'exit' from shell. TODO: try server sending ctrlStatOp to
-				// indicate to Reader? -rlm 20180428
-			}
-		}
-
-		if payloadLen > 16384 {
-			log.Printf("[Insane payloadLen:%v]\n", payloadLen)
-			c.Close()
-			return 1, errors.New("Insane payloadLen")
-		}
-		//log.Println("payloadLen:", payloadLen)
-
-		var payloadBytes = make([]byte, payloadLen)
-		n, err = io.ReadFull(c.c, payloadBytes)
-		//log.Print(" << Read ", n, " payloadBytes")
-
-		// Normal client 'exit' from interactive session will cause
-		// (on server side) err.Error() == "<iface/addr info ...>: use of closed network connection"
-		if err != nil && err.Error() != "EOF" {
-			if !strings.HasSuffix(err.Error(), "use of closed network connection") {
-				log.Println("unexpected Read() err:", err)
-			} else {
-				log.Println("[Client hung up]")
-			}
-		}
-
-		log.Printf("  <:ctext:\r\n%s\r\n", hex.Dump(payloadBytes[:n]))
-
-		db := bytes.NewBuffer(payloadBytes[:n]) //copying payloadBytes to db
-		// The StreamReader acts like a pipe, decrypting
-		// whatever is available and forwarding the result
-		// to the parameter of Read() as a normal io.Reader
-		rs := &cipher.StreamReader{S: c.r, R: db}
-		// The caller isn't necessarily reading the full payload so we need
-		// to decrypt ot an intermediate buffer, draining it on demand of caller
-		decryptN, err := rs.Read(payloadBytes)
-		log.Printf("  <-ptext:\r\n%s\r\n", hex.Dump(payloadBytes[:n]))
-		if err != nil {
-			panic(err)
-		}
-
-		// Throw away pkt if it's chaff (ie., caller to Read() won't see this data)
-		if ctrlStatOp == CSOChaff {
-			log.Printf("[Chaff pkt]\n")
-		} else if ctrlStatOp == CSOTermSize {
-			fmt.Sscanf(string(payloadBytes), "%d %d", &c.Rows, &c.Cols)
-			log.Printf("[TermSize pkt: rows %v cols %v]\n", c.Rows, c.Cols)
-			c.WinCh <- WinSize{c.Rows, c.Cols}
-		} else {
-			c.dBuf.Write(payloadBytes)
-			//log.Printf("c.dBuf: %s\n", hex.Dump(c.dBuf.Bytes()))
-		}
-
-		// Re-calculate hmac, compare with received value
-		c.rm.Write(payloadBytes)
-		hTmp := c.rm.Sum(nil)[0:4]
-		log.Printf("<%04x) HMAC:(i)%s (c)%02x\r\n", decryptN, hex.EncodeToString([]byte(hmacIn[0:])), hTmp)
-
-		// Log alert if hmac didn't match, corrupted channel
-		if !bytes.Equal(hTmp, []byte(hmacIn[0:])) /*|| hmacIn[0] > 0xf8*/ {
-			fmt.Println("** ALERT - detected HMAC mismatch, possible channel tampering **")
-			_, _ = c.c.Write([]byte{CSOHmacInvalid})
-		}
-	}
-
-	retN := c.dBuf.Len()
-	if retN > len(b) {
-		retN = len(b)
-	}
-
-	log.Printf("Read() got %d bytes\n", retN)
-	copy(b, c.dBuf.Next(retN))
-	//log.Printf("As Read() returns, c.dBuf is %d long: %s\n", c.dBuf.Len(), hex.Dump(c.dBuf.Bytes()))
-	return retN, nil
-}
-
-// Write a byte slice
-//
-// See go doc io.Writer
-func (c Conn) Write(b []byte) (n int, err error) {
-	return c.WritePacket(b, CSONone)
-}
-
-// Write a byte slice with specified ctrlStatusOp byte
-func (c Conn) WritePacket(b []byte, op byte) (n int, err error) {
-	//log.Printf("[Encrypting...]\r\n")
-	var hmacOut []uint8
-	var payloadLen uint32
-
-	log.Printf("  :>ptext:\r\n%s\r\n", hex.Dump(b))
-
-	payloadLen = uint32(len(b))
-
-	// Calculate hmac on payload
-	c.wm.Write(b)
-	hmacOut = c.wm.Sum(nil)[0:4]
-
-	log.Printf("  (%04x> HMAC(o):%s\r\n", payloadLen, hex.EncodeToString(hmacOut))
-
-	var wb bytes.Buffer
-	// The StreamWriter acts like a pipe, forwarding whatever is
-	// written to it through the cipher, encrypting as it goes
-	ws := &cipher.StreamWriter{S: c.w, W: &wb}
-	_, err = ws.Write(b)
-	if err != nil {
-		panic(err)
-	}
-	log.Printf("  ->ctext:\r\n%s\r\n", hex.Dump(wb.Bytes()))
-
-	ctrlStatOp := op
-	_ = binary.Write(c.c, binary.BigEndian, &ctrlStatOp)
-
-	// Write hmac LSB, payloadLen followed by payload
-	_ = binary.Write(c.c, binary.BigEndian, hmacOut)
-	_ = binary.Write(c.c, binary.BigEndian, payloadLen)
-
-	n, err = c.c.Write(wb.Bytes())
-	if err != nil {
-		//panic(err)
-		log.Println(err)
-	}
-	return
-}

hkexsh/hkexsh.go

@@ -1,240 +0,0 @@
-// hkexsh client
-//
-// Copyright (c) 2017-2018 Russell Magee
-// Licensed under the terms of the MIT license (see LICENSE.mit in this
-// distribution)
-//
-// golang implementation by Russ Magee (rmagee_at_gmail.com)
-package main
-
-import (
-	"flag"
-	"fmt"
-	"io"
-	"io/ioutil"
-	"log"
-	"os"
-	"os/exec"
-	"os/signal"
-	"os/user"
-	"strings"
-	"sync"
-	"syscall"
-
-	hkexsh "blitter.com/go/hkexsh"
-	isatty "github.com/mattn/go-isatty"
-)
-
-type cmdSpec struct {
-	op         []byte
-	who        []byte
-	cmd        []byte
-	authCookie []byte
-	status     int
-}
-
-// get terminal size using 'stty' command
-// (Most portable btwn Linux and MSYS/win32, but
-//  TODO: remove external dep on 'stty' utility)
-func getTermSize() (rows int, cols int, err error) {
-	cmd := exec.Command("stty", "size")
-	cmd.Stdin = os.Stdin
-	out, err := cmd.Output()
-	//fmt.Printf("out: %#v\n", string(out))
-	//fmt.Printf("err: %#v\n", err)
-
-	fmt.Sscanf(string(out), "%d %d\n", &rows, &cols)
-	if err != nil {
-		log.Fatal(err)
-	}
-	return
-}
-
-// Demo of a simple client that dials up to a simple test server to
-// send data.
-//
-// While conforming to the basic net.Conn interface HKex.Conn has extra
-// capabilities designed to allow apps to define connection options,
-// encryption/hmac settings and operations across the encrypted channel.
-//
-// Initial setup is the same as using plain net.Dial(), but one may
-// specify extra extension tags (strings) to set the cipher and hmac
-// setting desired; as well as the intended operation mode for the
-// connection (app-specific, passed through to the server to use or
-// ignore at its discretion).
-func main() {
-	var wg sync.WaitGroup
-
-	var dbg bool
-	var cAlg string
-	var hAlg string
-	var server string
-	var cmdStr string
-	var altUser string
-	var authCookie string
-	isInteractive := false
-
-	flag.StringVar(&cAlg, "c", "C_AES_256", "cipher [\"C_AES_256\" | \"C_TWOFISH_128\" | \"C_BLOWFISH_64\"]")
-	flag.StringVar(&hAlg, "h", "H_SHA256", "hmac [\"H_SHA256\"]")
-	flag.StringVar(&server, "s", "localhost:2000", "server hostname/address[:port]")
-	flag.StringVar(&cmdStr, "x", "", "command to run (default empty - interactive shell)")
-	flag.StringVar(&altUser, "u", "", "specify alternate user")
-	flag.StringVar(&authCookie, "a", "", "auth cookie (MultiCheese3999(tm) 2FA cookie")
-	flag.BoolVar(&dbg, "d", false, "debug logging")
-	flag.Parse()
-
-	if dbg {
-		log.SetOutput(os.Stdout)
-	} else {
-		log.SetOutput(ioutil.Discard)
-	}
-
-	conn, err := hkexsh.Dial("tcp", server, cAlg, hAlg)
-	if err != nil {
-		fmt.Println("Err!")
-		panic(err)
-	}
-	defer conn.Close()
-	// From this point on, conn is a secure encrypted channel
-
-	rows := 0
-	cols := 0
-
-	// Set stdin in raw mode if it's an interactive session
-	// TODO: send flag to server side indicating this
-	//  affects shell command used
-	var oldState *hkexsh.State
-	if isatty.IsTerminal(os.Stdin.Fd()) {
-		oldState, err = hkexsh.MakeRaw(int(os.Stdin.Fd()))
-		if err != nil {
-			panic(err)
-		}
-		defer func() { _ = hkexsh.Restore(int(os.Stdin.Fd()), oldState) }() // Best effort.
-	} else {
-		log.Println("NOT A TTY")
-	}
-
-	var uname string
-	if len(altUser) == 0 {
-		u, _ := user.Current()
-		uname = u.Username
-	} else {
-		uname = altUser
-	}
-
-	var op []byte
-	if len(cmdStr) == 0 {
-		op = []byte{'s'}
-		isInteractive = true
-	} else if cmdStr == "-" {
-		op = []byte{'c'}
-		cmdStdin, err := ioutil.ReadAll(os.Stdin)
-		if err != nil {
-			panic(err)
-		}
-		cmdStr = strings.Trim(string(cmdStdin), "\r\n")
-	} else {
-		op = []byte{'c'}
-	}
-
-	if len(authCookie) == 0 {
-		fmt.Printf("Gimme cookie:")
-		ab, err := hkexsh.ReadPassword(int(os.Stdin.Fd()))
-		fmt.Printf("\r\n")
-		if err != nil {
-			panic(err)
-		}
-		authCookie = string(ab)
-	}
-
-	rec := &cmdSpec{
-		op:         op,
-		who:        []byte(uname),
-		cmd:        []byte(cmdStr),
-		authCookie: []byte(authCookie),
-		status:     0}
-
-	_, err = fmt.Fprintf(conn, "%d %d %d %d\n",
-		len(rec.op), len(rec.who), len(rec.cmd), len(rec.authCookie))
-
-	_, err = conn.Write(rec.op)
-	_, err = conn.Write(rec.who)
-	_, err = conn.Write(rec.cmd)
-	_, err = conn.Write(rec.authCookie)
-
-	//client reader (from server) goroutine
-	wg.Add(1)
-	go func() {
-		// By deferring a call to wg.Done(),
-		// each goroutine guarantees that it marks
-		// its direction's stream as finished.
-		//
-		// Whichever direction's goroutine finishes first
-		// will call wg.Done() once more, explicitly, to
-		// hang up on the other side, so that this client
-		// exits immediately on an EOF from either side.
-		defer wg.Done()
-
-		// io.Copy() expects EOF so this will
-		// exit with inerr == nil
-		_, inerr := io.Copy(os.Stdout, conn)
-		if inerr != nil {
-			if inerr.Error() != "EOF" {
-				fmt.Println(inerr)
-				_ = hkexsh.Restore(int(os.Stdin.Fd()), oldState) // Best effort.
-				os.Exit(1)
-			}
-		}
-
-		if isInteractive {
-			log.Println("[Got EOF]")
-			wg.Done() // server hung up, close WaitGroup to exit client
-		}
-	}()
-
-	if isInteractive {
-		// Handle pty resizes (notify server side)
-		ch := make(chan os.Signal, 1)
-		signal.Notify(ch, syscall.SIGWINCH)
-		wg.Add(1)
-		go func() {
-			defer wg.Done()
-
-			for range ch {
-				// Query client's term size so we can communicate it to server
-				// pty after interactive session starts
-				rows, cols, err = getTermSize()
-				log.Printf("[rows %v cols %v]\n", rows, cols)
-				if err != nil {
-					panic(err)
-				}
-				termSzPacket := fmt.Sprintf("%d %d", rows, cols)
-				conn.WritePacket([]byte(termSzPacket), hkexsh.CSOTermSize)
-			}
-		}()
-		ch <- syscall.SIGWINCH // Initial resize.
-
-		// client writer (to server) goroutine
-		wg.Add(1)
-		go func() {
-			defer wg.Done()
-
-			// io.Copy() expects EOF so this will
-			// exit with outerr == nil
-			_, outerr := io.Copy(conn, os.Stdin)
-			if outerr != nil {
-				log.Println(outerr)
-				if outerr.Error() != "EOF" {
-					fmt.Println(outerr)
-					_ = hkexsh.Restore(int(os.Stdin.Fd()), oldState) // Best effort.
-					os.Exit(2)
-				}
-			}
-			log.Println("[Sent EOF]")
-			wg.Done() // client hung up, close WaitGroup to exit client
-		}()
-	}
-
-	// Wait until both stdin and stdout goroutines finish
-	wg.Wait()
-}

hkexshd/hkexshd.go

@@ -1,274 +0,0 @@
-// hkexshd server
-//
-// Copyright (c) 2017-2018 Russell Magee
-// Licensed under the terms of the MIT license (see LICENSE.mit in this
-// distribution)
-//
-// golang implementation by Russ Magee (rmagee_at_gmail.com)
-package main
-
-import (
-	"flag"
-	"fmt"
-	"io"
-	"io/ioutil"
-	"log"
-	"os"
-	"os/exec"
-	"os/user"
-	"syscall"
-
-	hkexsh "blitter.com/go/hkexsh"
-	"blitter.com/go/hkexsh/spinsult"
-	"github.com/kr/pty"
-)
-
-type cmdSpec struct {
-	op         []byte
-	who        []byte
-	cmd        []byte
-	authCookie []byte
-	termRows   []byte
-	termCols   []byte
-	status     int
-}
-
-/* -------------------------------------------------------------- */
-
-/*
- // Run a command (via os.exec) as a specific user
-//
-// Uses ptys to support commands which expect a terminal.
-func runCmdAs(who string, cmd string, conn hkex.Conn) (err error) {
-	u, _ := user.Lookup(who)
-	var uid, gid uint32
-	fmt.Sscanf(u.Uid, "%d", &uid)
-	fmt.Sscanf(u.Gid, "%d", &gid)
-	fmt.Println("uid:", uid, "gid:", gid)
-
-	args := strings.Split(cmd, " ")
-	arg0 := args[0]
-	args = args[1:]
-	c := exec.Command(arg0, args...)
-	c.SysProcAttr = &syscall.SysProcAttr{}
-	c.SysProcAttr.Credential = &syscall.Credential{Uid: uid, Gid: gid}
-	c.Stdin = conn
-	c.Stdout = conn
-	c.Stderr = conn
-
-	// Start the command with a pty.
-	ptmx, err := pty.Start(c) // returns immediately with ptmx file
-	if err != nil {
-		return err
-	}
-	// Make sure to close the pty at the end.
-	defer func() { _ = ptmx.Close() }() // Best effort.
-	// Copy stdin to the pty and the pty to stdout.
-	go func() { _, _ = io.Copy(ptmx, conn) }()
-	_, _ = io.Copy(conn, ptmx)
-
-	//err = c.Run()  // returns when c finishes.
-
-	if err != nil {
-		log.Printf("Command finished with error: %v", err)
-		log.Printf("[%s]\n", cmd)
-	}
-	return
-}
-*/
-
-// Run a command (via default shell) as a specific user
-//
-// Uses ptys to support commands which expect a terminal.
-func runShellAs(who string, cmd string, interactive bool, conn hkexsh.Conn) (err error) {
-	u, _ := user.Lookup(who)
-	var uid, gid uint32
-	fmt.Sscanf(u.Uid, "%d", &uid)
-	fmt.Sscanf(u.Gid, "%d", &gid)
-	log.Println("uid:", uid, "gid:", gid)
-
-	// Need to clear server's env and set key vars of the
-	// target user. This isn't perfect (TERM doesn't seem to
-	// work 100%; ANSI/xterm colour isn't working even
-	// if we set "xterm" or "ansi" here; and line count
-	// reported by 'stty -a' defaults to 24 regardless
-	// of client shell window used to run client.
-	// Investigate -- rlm 2018-01-26)
-	os.Clearenv()
-	os.Setenv("HOME", u.HomeDir)
-	os.Setenv("TERM", "vt102") // TODO: server or client option?
-
-	var c *exec.Cmd
-	if interactive {
-		c = exec.Command("/bin/bash", "-i", "-l")
-	} else {
-		c = exec.Command("/bin/bash", "-c", cmd)
-	}
-	//If os.Clearenv() isn't called by server above these will be seen in the
-	//client's session env.
-	//c.Env = []string{"HOME=" + u.HomeDir, "SUDO_GID=", "SUDO_UID=", "SUDO_USER=", "SUDO_COMMAND=", "MAIL=", "LOGNAME="+who}
-	c.Dir = u.HomeDir
-	c.SysProcAttr = &syscall.SysProcAttr{}
-	c.SysProcAttr.Credential = &syscall.Credential{Uid: uid, Gid: gid}
-	c.Stdin = conn
-	c.Stdout = conn
-	c.Stderr = conn
-
-	// Start the command with a pty.
-	ptmx, err := pty.Start(c) // returns immediately with ptmx file
-	if err != nil {
-		return err
-	}
-	// Make sure to close the pty at the end.
-	defer func() { _ = ptmx.Close() }() // Best effort.
-
-	// Watch for term resizes
-	go func() {
-		for sz := range conn.WinCh {
-			log.Printf("[Setting term size to: %v %v]\n", sz.Rows, sz.Cols)
-			pty.Setsize(ptmx, &pty.Winsize{Rows: sz.Rows, Cols: sz.Cols})
-		}
-	}()
-
-	// Copy stdin to the pty.. (bgnd goroutine)
-	go func() {
-		_, _ = io.Copy(ptmx, conn)
-	}()
-	// ..and the pty to stdout.
-	_, _ = io.Copy(conn, ptmx)
-
-	//err = c.Run()  // returns when c finishes.
-
-	log.Printf("[%s]\n", cmd)
-	if err != nil {
-		log.Printf("Command finished with error: %v", err)
-	}
-	return
-}
-
-func rejectUserMsg() string {
-	return "Begone, " + spinsult.GetSentence() + "\r\n"
-}
-
-// Demo of a simple server that listens and spawns goroutines for each
-// connecting client. Note this code is identical to standard tcp
-// server code, save for declaring 'hkex' rather than 'net'
-// Listener and Conns. The KEx and encrypt/decrypt is done within the type.
-// Compare to 'serverp.go' in this directory to see the equivalence.
-func main() {
-	var dbg bool
-	var laddr string
-
-	flag.StringVar(&laddr, "l", ":2000", "interface[:port] to listen")
-	flag.BoolVar(&dbg, "d", false, "debug logging")
-	flag.Parse()
-
-	if dbg {
-		log.SetOutput(os.Stdout)
-	} else {
-		log.SetOutput(ioutil.Discard)
-	}
-
-	// Listen on TCP port 2000 on all available unicast and
-	// anycast IP addresses of the local system.
-	l, err := hkexsh.Listen("tcp", laddr)
-	if err != nil {
-		log.Fatal(err)
-	}
-	defer l.Close()
-
-	log.Println("Serving on", laddr)
-	for {
-		// Wait for a connection.
-		conn, err := l.Accept()
-		if err != nil {
-			log.Printf("Accept() got error(%v), hanging up.\n", err)
-			conn.Close()
-			//log.Fatal(err)
-		} else {
-			log.Println("Accepted client")
-
-			// Handle the connection in a new goroutine.
-			// The loop then returns to accepting, so that
-			// multiple connections may be served concurrently.
-			go func(c hkexsh.Conn) (e error) {
-				defer c.Close()
-
-				//We use io.ReadFull() here to guarantee we consume
-				//just the data we want for the cmdSpec, and no more.
-				//Otherwise data will be sitting in the channel that isn't
-				//passed down to the command handlers.
-				var rec cmdSpec
-				var len1, len2, len3, len4 uint32
-
-				n, err := fmt.Fscanf(c, "%d %d %d %d\n", &len1, &len2, &len3, &len4)
-				log.Printf("cmdSpec read:%d %d %d %d\n", len1, len2, len3, len4)
-
-				if err != nil || n < 4 {
-					log.Println("[Bad cmdSpec fmt]")
-					return err
-				}
-				//fmt.Printf("  lens:%d %d %d %d\n", len1, len2, len3, len4)
-
-				rec.op = make([]byte, len1, len1)
-				_, err = io.ReadFull(c, rec.op)
-				if err != nil {
-					log.Println("[Bad cmdSpec.op]")
-					return err
-				}
-				rec.who = make([]byte, len2, len2)
-				_, err = io.ReadFull(c, rec.who)
-				if err != nil {
-					log.Println("[Bad cmdSpec.who]")
-					return err
-				}
-
-				rec.cmd = make([]byte, len3, len3)
-				_, err = io.ReadFull(c, rec.cmd)
-				if err != nil {
-					log.Println("[Bad cmdSpec.cmd]")
-					return err
-				}
-
-				rec.authCookie = make([]byte, len4, len4)
-				_, err = io.ReadFull(c, rec.authCookie)
-				if err != nil {
-					log.Println("[Bad cmdSpec.authCookie]")
-					return err
-				}
-
-				log.Printf("[cmdSpec: op:%c who:%s cmd:%s auth:****]\n",
-					rec.op[0], string(rec.who), string(rec.cmd))
-
-				valid, allowedCmds := hkexsh.AuthUser(string(rec.who), string(rec.authCookie), "/etc/hkexsh.passwd")
-				if !valid {
-					log.Println("Invalid user", string(rec.who))
-					c.Write([]byte(rejectUserMsg()))
-					return
-				}
-				log.Printf("[allowedCmds:%s]\n", allowedCmds)
-
-				if rec.op[0] == 'c' {
-					// Non-interactive command
-					log.Println("[Running command]")
-					runShellAs(string(rec.who), string(rec.cmd), false, conn)
-					// Returned hopefully via an EOF or exit/logout;
-					// Clear current op so user can enter next, or EOF
-					rec.op[0] = 0
-					log.Println("[Command complete]")
-				} else if rec.op[0] == 's' {
-					log.Println("[Running shell]")
-					runShellAs(string(rec.who), string(rec.cmd), true, conn)
-					// Returned hopefully via an EOF or exit/logout;
-					// Clear current op so user can enter next, or EOF
-					rec.op[0] = 0
-					log.Println("[Exiting shell]")
-				} else {
-					log.Println("[Bad cmdSpec]")
-				}
-				return
-			}(conn)
-		} // Accept() success
-	} //endfor
-	log.Println("[Exiting]")
-}

logger/Makefile

@@ -0,0 +1,12 @@
+.PHONY: clean all lint
+
+EXE = $(notdir $(shell pwd))
+
+all:
+	go build .
+
+clean:
+	$(RM) $(EXE) $(EXE).exe
+
+lint:
+	gometalinter --deadline 60s | sort

logger/logger_bsd.go

@@ -0,0 +1,156 @@
+// +build freebsd
+
+// Package logger is a wrapper around UNIX syslog, so that it also may
+// be wrapped with something else for Windows (Sadly, the stdlib log/syslog
+// is frozen, and there is no Windows implementation.)
+package logger
+
+import (
+	sl "log/syslog"
+)
+
+// Priority is the logger priority
+type Priority = sl.Priority
+
+// Writer is a syslog Writer
+type Writer = sl.Writer
+
+// nolint: golint
+const (
+	// Severity.
+
+	// From /usr/include/sys/syslog.h.
+	// These are the same on Linux, BSD, and OS X.
+	LOG_EMERG Priority = iota
+	LOG_ALERT
+	LOG_CRIT
+	LOG_ERR
+	LOG_WARNING
+	LOG_NOTICE
+	LOG_INFO
+	LOG_DEBUG
+)
+
+// nolint: golint
+const (
+	// Facility.
+
+	// From /usr/include/sys/syslog.h.
+	// These are the same up to LOG_FTP on Linux, BSD, and OS X.
+	LOG_KERN Priority = iota << 3
+	LOG_USER
+	LOG_MAIL
+	LOG_DAEMON
+	LOG_AUTH
+	LOG_SYSLOG
+	LOG_LPR
+	LOG_NEWS
+	LOG_UUCP
+	LOG_CRON
+	LOG_AUTHPRIV
+	LOG_FTP
+	_ // unused
+	_ // unused
+	_ // unused
+	_ // unused
+	LOG_LOCAL0
+	LOG_LOCAL1
+	LOG_LOCAL2
+	LOG_LOCAL3
+	LOG_LOCAL4
+	LOG_LOCAL5
+	LOG_LOCAL6
+	LOG_LOCAL7
+)
+
+var (
+	l *sl.Writer
+)
+
+// New returns a new log Writer.
+func New(flags Priority, tag string) (w *Writer, e error) {
+	w, e = sl.New(flags, tag)
+	l = w
+	return w, e
+}
+
+// Alert returns a log Alert error
+func Alert(s string) error {
+	if l != nil {
+		return l.Alert(s)
+	}
+	return nil
+
+}
+
+// LogClose closes the log Writer.
+func LogClose() error {
+	if l != nil {
+		return l.Close()
+	}
+	return nil
+}
+
+// LogCrit returns a log Alert error
+func LogCrit(s string) error {
+	if l != nil {
+		return l.Crit(s)
+	}
+	return nil
+}
+
+// LogDebug returns a log Debug error
+func LogDebug(s string) error {
+	if l != nil {
+		return l.Debug(s)
+	}
+	return nil
+}
+
+// LogEmerg returns a log Emerg error
+func LogEmerg(s string) error {
+	if l != nil {
+		return l.Emerg(s)
+	}
+	return nil
+}
+
+// LogErr returns a log Err error
+func LogErr(s string) error {
+	if l != nil {
+		return l.Err(s)
+	}
+	return nil
+}
+
+// LogInfo returns a log Info error
+func LogInfo(s string) error {
+	if l != nil {
+		return l.Info(s)
+	}
+	return nil
+}
+
+// LogNotice returns a log Notice error
+func LogNotice(s string) error {
+	if l != nil {
+		return l.Notice(s)
+	}
+	return nil
+}
+
+// LogWarning returns a log Warning error
+func LogWarning(s string) error {
+	if l != nil {
+		return l.Warning(s)
+	}
+	return nil
+}
+
+// LogWrite writes to the logger at default level
+func LogWrite(b []byte) (int, error) {
+	if l != nil {
+		return l.Write(b)
+	}
+	return len(b),nil
+}

logger/logger_linux.go

@@ -0,0 +1,156 @@
+// +build linux
+
+// Package logger is a wrapper around UNIX syslog, so that it also may
+// be wrapped with something else for Windows (Sadly, the stdlib log/syslog
+// is frozen, and there is no Windows implementation.)
+package logger
+
+import (
+	sl "log/syslog"
+)
+
+// Priority is the logger priority
+type Priority = sl.Priority
+
+// Writer is a syslog Writer
+type Writer = sl.Writer
+
+// nolint: golint
+const (
+	// Severity.
+
+	// From /usr/include/sys/syslog.h.
+	// These are the same on Linux, BSD, and OS X.
+	LOG_EMERG Priority = iota
+	LOG_ALERT
+	LOG_CRIT
+	LOG_ERR
+	LOG_WARNING
+	LOG_NOTICE
+	LOG_INFO
+	LOG_DEBUG
+)
+
+// nolint: golint
+const (
+	// Facility.
+
+	// From /usr/include/sys/syslog.h.
+	// These are the same up to LOG_FTP on Linux, BSD, and OS X.
+	LOG_KERN Priority = iota << 3
+	LOG_USER
+	LOG_MAIL
+	LOG_DAEMON
+	LOG_AUTH
+	LOG_SYSLOG
+	LOG_LPR
+	LOG_NEWS
+	LOG_UUCP
+	LOG_CRON
+	LOG_AUTHPRIV
+	LOG_FTP
+	_ // unused
+	_ // unused
+	_ // unused
+	_ // unused
+	LOG_LOCAL0
+	LOG_LOCAL1
+	LOG_LOCAL2
+	LOG_LOCAL3
+	LOG_LOCAL4
+	LOG_LOCAL5
+	LOG_LOCAL6
+	LOG_LOCAL7
+)
+
+var (
+	l *sl.Writer
+)
+
+// New returns a new log Writer.
+func New(flags Priority, tag string) (w *Writer, e error) {
+	w, e = sl.New(flags, tag)
+	l = w
+	return w, e
+}
+
+// Alert returns a log Alert error
+func Alert(s string) error {
+	if l != nil {
+		return l.Alert(s)
+	}
+	return nil
+
+}
+
+// LogClose closes the log Writer.
+func LogClose() error {
+	if l != nil {
+		return l.Close()
+	}
+	return nil
+}
+
+// LogCrit returns a log Alert error
+func LogCrit(s string) error {
+	if l != nil {
+		return l.Crit(s)
+	}
+	return nil
+}
+
+// LogDebug returns a log Debug error
+func LogDebug(s string) error {
+	if l != nil {
+		return l.Debug(s)
+	}
+	return nil
+}
+
+// LogEmerg returns a log Emerg error
+func LogEmerg(s string) error {
+	if l != nil {
+		return l.Emerg(s)
+	}
+	return nil
+}
+
+// LogErr returns a log Err error
+func LogErr(s string) error {
+	if l != nil {
+		return l.Err(s)
+	}
+	return nil
+}
+
+// LogInfo returns a log Info error
+func LogInfo(s string) error {
+	if l != nil {
+		return l.Info(s)
+	}
+	return nil
+}
+
+// LogNotice returns a log Notice error
+func LogNotice(s string) error {
+	if l != nil {
+		return l.Notice(s)
+	}
+	return nil
+}
+
+// LogWarning returns a log Warning error
+func LogWarning(s string) error {
+	if l != nil {
+		return l.Warning(s)
+	}
+	return nil
+}
+
+// LogWrite writes to the logger at default level
+func LogWrite(b []byte) (int, error) {
+	if l != nil {
+		return l.Write(b)
+	}
+	return len(b),nil
+}

logger/logger_windows.go

@@ -0,0 +1,94 @@
+// +build windows
+
+// Wrapper around UNIX syslog, so that it also may be wrapped
+// with something else for Windows.
+package logger
+
+import (
+	"os"
+)
+
+type Priority = int
+type Writer = os.File
+
+
+const (
+	// Severity.
+
+	// From /usr/include/sys/syslog.h.
+	// These are the same on Linux, BSD, and OS X.
+	LOG_EMERG Priority = iota
+	LOG_ALERT
+	LOG_CRIT
+	LOG_ERR
+	LOG_WARNING
+	LOG_NOTICE
+	LOG_INFO
+	LOG_DEBUG
+)
+
+const (
+	// Facility.
+
+	// From /usr/include/sys/syslog.h.
+	// These are the same up to LOG_FTP on Linux, BSD, and OS X.
+	LOG_KERN Priority = iota << 3
+	LOG_USER
+	LOG_MAIL
+	LOG_DAEMON
+	LOG_AUTH
+	LOG_SYSLOG
+	LOG_LPR
+	LOG_NEWS
+	LOG_UUCP
+	LOG_CRON
+	LOG_AUTHPRIV
+	LOG_FTP
+	_ // unused
+	_ // unused
+	_ // unused
+	_ // unused
+	LOG_LOCAL0
+	LOG_LOCAL1
+	LOG_LOCAL2
+	LOG_LOCAL3
+	LOG_LOCAL4
+	LOG_LOCAL5
+	LOG_LOCAL6
+	LOG_LOCAL7
+)
+
+func New(flags Priority, tag string) (w *Writer, e error) {
+	return os.Stderr, nil
+}
+
+func Alert(s string) error {
+		return nil
+}
+func LogClose() error {
+		return nil
+}
+func LogCrit(s string) error {
+		return nil
+}
+func LogDebug(s string) error {
+		return nil
+}
+func LogEmerg(s string) error {
+		return nil
+}
+func LogErr(s string) error {
+		return nil
+}
+func LogInfo(s string) error {
+		return nil
+}
+func LogNotice(s string) error {
+		return nil
+}
+func LogWarning(s string) error {
+		return nil
+}
+func LogWrite(b []byte) (int, error) {
+		return len(b), nil
+}

session.go

@@ -0,0 +1,139 @@
+package xs
+
+// Package xs - a secure terminal client/server written from scratch in Go
+//
+// Copyright (c) 2017-2020 Russell Magee
+// Licensed under the terms of the MIT license (see LICENSE.mit in this
+// distribution)
+//
+// golang implementation by Russ Magee (rmagee_at_gmail.com)
+
+// Session info/routines for the HKExSh
+
+import (
+	"fmt"
+	"runtime"
+)
+
+// Session holds essential bookkeeping info about an active session.
+type Session struct {
+	op         []byte
+	who        []byte
+	connhost   []byte
+	termtype   []byte // client initial $TERM
+	cmd        []byte
+	authCookie []byte
+	status     uint32 // exit status (0-255 is std UNIX status)
+}
+
+// Output Session record as a string. Implements Stringer interface.
+func (h *Session) String() string {
+	return fmt.Sprintf("xs.Session:\nOp:%v\nWho:%v\nCmd:%v\nAuthCookie:%v\nStatus:%v",
+		h.op, h.who, h.cmd, h.AuthCookie(false), h.status)
+}
+
+// Op returns the op code of the Session (interactive shell, cmd, ...)
+func (h Session) Op() []byte {
+	return h.op
+}
+
+// SetOp stores the op code desired for a Session.
+func (h *Session) SetOp(o []byte) {
+	h.op = o
+}
+
+// Who returns the user associated with a Session.
+func (h Session) Who() []byte {
+	return h.who
+}
+
+// SetWho sets the username associated with a Session.
+func (h *Session) SetWho(w []byte) {
+	h.who = w
+}
+
+// ConnHost returns the connecting hostname/IP string for a Session.
+func (h Session) ConnHost() []byte {
+	return h.connhost
+}
+
+// SetConnHost stores the connecting hostname/IP string for a Session.
+func (h *Session) SetConnHost(n []byte) {
+	h.connhost = n
+}
+
+// TermType returns the TERM env variable reported by the client initiating
+// a Session.
+func (h Session) TermType() []byte {
+	return h.termtype
+}
+
+// SetTermType stores the TERM env variable supplied by the client initiating
+// a Session.
+func (h *Session) SetTermType(t []byte) {
+	h.termtype = t
+}
+
+// Cmd returns the command requested for execution by a client initiating
+// the Session.
+func (h Session) Cmd() []byte {
+	return h.cmd
+}
+
+// SetCmd stores the command request by the client for execution when initiating
+// the Session.
+func (h *Session) SetCmd(c []byte) {
+	h.cmd = c
+}
+
+// AuthCookie returns the authcookie (essentially the password) used for
+// authorization of the Session. This return value is censored unless
+// reallyShow is true (so dumps of Session Info do not accidentally leak it).
+func (h Session) AuthCookie(reallyShow bool) []byte {
+	if reallyShow {
+		return h.authCookie
+	}
+	return []byte("**REDACTED**")
+}
+
+// SetAuthCookie stores the authcookie (essentially the password) used to
+// authenticate the Session.
+func (h *Session) SetAuthCookie(a []byte) {
+	h.authCookie = a
+}
+
+// ClearAuthCookie attempts to scrub the Session's stored authcookie.
+//
+// This should of course be called as soon as possible after authentication
+// and it is no longer required.
+func (h *Session) ClearAuthCookie() {
+	for i := range h.authCookie {
+		h.authCookie[i] = 0
+	}
+	runtime.GC()
+}
+
+// Status returns the (current) Session status code.
+//
+// This usually corresponds to a UNIX shell exit code, but
+// extended codes are returns at times to indicate internal errors.
+func (h Session) Status() uint32 {
+	return h.status
+}
+
+// SetStatus stores the current Session status code.
+func (h *Session) SetStatus(s uint32) {
+	h.status = s
+}
+
+// NewSession returns a new Session record.
+func NewSession(op, who, connhost, ttype, cmd, authcookie []byte, status uint32) *Session {
+	return &Session{
+		op:         op,
+		who:        who,
+		connhost:   connhost,
+		termtype:   ttype,
+		cmd:        cmd,
+		authCookie: authcookie,
+		status:     status}
+}

session_test.go

@@ -0,0 +1,30 @@
+package xs
+
+import (
+	"testing"
+)
+
+func _newMockSession() (s *Session) {
+	s = &Session{op: []byte("A"),
+		who:        []byte("johndoe"),
+		connhost:   []byte("host"),
+		termtype:   []byte("vt100"),
+		cmd:        []byte("/bin/false"),
+		authCookie: []byte("authcookie"),
+		status:     0}
+	return s
+}
+
+func TestSessionAuthCookieShowTrue(t *testing.T) {
+	sess := _newMockSession()
+	if string(sess.AuthCookie(true)) != string(sess.authCookie) {
+		t.Fatal("Failed to return unredacted authcookie on request")
+	}
+}
+
+func TestSessionAuthCookieShowFalse(t *testing.T) {
+	sess := _newMockSession()
+	if string(sess.AuthCookie(false)) != string("**REDACTED**") {
+		t.Fatal("Failed to return redacted authcookie on request")
+	}
+}

spinsult/Makefile

@@ -0,0 +1,17 @@
+.PHONY: info clean lib
+
+all: lib
+
+clean:
+	go clean .
+
+lib: info
+	go install .
+
+ifneq ($(MSYSTEM),)
+info:
+	@echo "Building for Windows (MSYS)"
+else
+info:
+	@echo "Building for Linux"
+endif

termmode_bsd.go

@@ -0,0 +1,128 @@
+// +build freebsd
+
+package xs
+
+import (
+	"errors"
+	"io"
+	"unsafe"
+
+	unix "golang.org/x/sys/unix"
+)
+
+/* -------------
+ * minimal terminal APIs brought in from ssh/terminal
+ * (they have no real business being there as they aren't specific to
+ * ssh, but as of Go v1.10, late 2019, core go stdlib hasn't yet done
+ * the planned terminal lib reorgs.)
+ * ------------- */
+
+// From github.com/golang/crypto/blob/master/ssh/terminal/util_linux.go
+const getTermios = unix.TIOCGETA
+const setTermios = unix.TIOCSETA
+
+// From github.com/golang/crypto/blob/master/ssh/terminal/util.go
+
+// State contains the state of a terminal.
+type State struct {
+	termios unix.Termios
+}
+
+// MakeRaw put the terminal connected to the given file descriptor into raw
+// mode and returns the previous state of the terminal so that it can be
+// restored.
+func MakeRaw(fd uintptr) (*State, error) {
+	var oldState State
+	if _, _, err := unix.Syscall(unix.SYS_IOCTL, fd, getTermios, uintptr(unsafe.Pointer(&oldState.termios))); err != 0 {
+		return nil, err
+	}
+
+	newState := oldState.termios
+	newState.Iflag &^= (unix.IGNBRK | unix.BRKINT | unix.PARMRK | unix.ISTRIP | unix.INLCR | unix.IGNCR | unix.ICRNL | unix.IXON)
+	newState.Oflag &^= unix.OPOST
+	newState.Lflag &^= (unix.ECHO | unix.ECHONL | unix.ICANON | unix.ISIG | unix.IEXTEN)
+	newState.Cflag &^= (unix.CSIZE | unix.PARENB)
+	newState.Cflag |= unix.CS8
+	newState.Cc[unix.VMIN] = 1
+	newState.Cc[unix.VTIME] = 0
+
+	if _, _, err := unix.Syscall(unix.SYS_IOCTL, fd, setTermios, uintptr(unsafe.Pointer(&newState))); err != 0 {
+		return nil, err
+	}
+
+	return &oldState, nil
+}
+
+// Restore restores the terminal connected to the given file descriptor to a
+// previous state.
+func Restore(fd uintptr, state *State) error {
+	if state != nil {
+		if _, _, err := unix.Syscall(unix.SYS_IOCTL, fd, setTermios, uintptr(unsafe.Pointer(state))); err != 0 {
+			return err
+		} else {
+			return nil
+		}
+	} else {
+		return errors.New("nil State")
+	}
+}
+
+// ReadPassword reads a line of input from a terminal without local echo.  This
+// is commonly used for inputting passwords and other sensitive data. The slice
+// returned does not include the \n.
+func ReadPassword(fd uintptr) ([]byte, error) {
+	var oldState State
+	if _, _, err := unix.Syscall(unix.SYS_IOCTL, fd, getTermios, uintptr(unsafe.Pointer(&oldState.termios))); err != 0 {
+		return nil, err
+	}
+
+	newState := oldState.termios
+	newState.Lflag &^= unix.ECHO
+	newState.Lflag |= unix.ICANON | unix.ISIG
+	newState.Iflag |= unix.ICRNL
+	if _, _, err := unix.Syscall(unix.SYS_IOCTL, fd, setTermios, uintptr(unsafe.Pointer(&newState))); err != 0 {
+		return nil, err
+	}
+
+	defer func() {
+		unix.Syscall(unix.SYS_IOCTL, fd, setTermios, uintptr(unsafe.Pointer(&oldState.termios)))
+	}()
+
+	return readPasswordLine(passwordReader(fd))
+}
+
+// passwordReader is an io.Reader that reads from a specific file descriptor.
+type passwordReader int
+
+func (r passwordReader) Read(buf []byte) (int, error) {
+	return unix.Read(int(r), buf)
+}
+
+// readPasswordLine reads from reader until it finds \n or io.EOF.
+// The slice returned does not include the \n.
+// readPasswordLine also ignores any \r it finds.
+func readPasswordLine(reader io.Reader) ([]byte, error) {
+	var buf [1]byte
+	var ret []byte
+
+	for {
+		n, err := reader.Read(buf[:])
+		if n > 0 {
+			switch buf[0] {
+			case '\n':
+				return ret, nil
+			case '\r':
+				// remove \r from passwords on Windows
+			default:
+				ret = append(ret, buf[0])
+			}
+			continue
+		}
+		if err != nil {
+			if err == io.EOF && len(ret) > 0 {
+				return ret, nil
+			}
+			return ret, err
+		}
+	}
+}

termmode_linux.go

@@ -1,8 +1,9 @@
 // +build linux
 
-package hkexsh
+package xs
 
 import (
+	"errors"
 	"io"
 
 	unix "golang.org/x/sys/unix"
@@ -11,7 +12,7 @@ import (
 /* -------------
  * minimal terminal APIs brought in from ssh/terminal
  * (they have no real business being there as they aren't specific to
- * ssh, but as of Go v1.10, early 2018, core go stdlib hasn't yet done
+ * ssh, but as of Go v1.10, late 2019, core go stdlib hasn't yet done
  * the planned terminal lib reorgs.)
  * ------------- */
 
@@ -20,6 +21,7 @@ const ioctlReadTermios = unix.TCGETS
 const ioctlWriteTermios = unix.TCSETS
 
 // From github.com/golang/crypto/blob/master/ssh/terminal/util.go
+
 // State contains the state of a terminal.
 type State struct {
 	termios unix.Termios
@@ -28,8 +30,8 @@ type State struct {
 // MakeRaw put the terminal connected to the given file descriptor into raw
 // mode and returns the previous state of the terminal so that it can be
 // restored.
-func MakeRaw(fd int) (*State, error) {
+func MakeRaw(fd uintptr) (*State, error) {
-	termios, err := unix.IoctlGetTermios(fd, ioctlReadTermios)
+	termios, err := unix.IoctlGetTermios(int(fd), ioctlReadTermios)
 	if err != nil {
 		return nil, err
 	}
@@ -45,7 +47,7 @@ func MakeRaw(fd int) (*State, error) {
 	termios.Cflag |= unix.CS8
 	termios.Cc[unix.VMIN] = 1
 	termios.Cc[unix.VTIME] = 0
-	if err := unix.IoctlSetTermios(fd, ioctlWriteTermios, termios); err != nil {
+	if err := unix.IoctlSetTermios(int(fd), ioctlWriteTermios, termios); err != nil {
 		return nil, err
 	}
 
@@ -54,8 +56,8 @@ func MakeRaw(fd int) (*State, error) {
 
 // GetState returns the current state of a terminal which may be useful to
 // restore the terminal after a signal.
-func GetState(fd int) (*State, error) {
+func GetState(fd uintptr) (*State, error) {
-	termios, err := unix.IoctlGetTermios(fd, ioctlReadTermios)
+	termios, err := unix.IoctlGetTermios(int(fd), ioctlReadTermios)
 	if err != nil {
 		return nil, err
 	}
@@ -65,15 +67,19 @@ func GetState(fd int) (*State, error) {
 
 // Restore restores the terminal connected to the given file descriptor to a
 // previous state.
-func Restore(fd int, state *State) error {
+func Restore(fd uintptr, state *State) error {
-	return unix.IoctlSetTermios(fd, ioctlWriteTermios, &state.termios)
+	if state != nil {
+		return unix.IoctlSetTermios(int(fd), ioctlWriteTermios, &state.termios)
+	} else {
+		return errors.New("nil State")
+	}
 }
 
 // ReadPassword reads a line of input from a terminal without local echo.  This
 // is commonly used for inputting passwords and other sensitive data. The slice
 // returned does not include the \n.
-func ReadPassword(fd int) ([]byte, error) {
+func ReadPassword(fd uintptr) ([]byte, error) {
-	termios, err := unix.IoctlGetTermios(fd, ioctlReadTermios)
+	termios, err := unix.IoctlGetTermios(int(fd), ioctlReadTermios)
 	if err != nil {
 		return nil, err
 	}
@@ -82,12 +88,12 @@ func ReadPassword(fd int) ([]byte, error) {
 	newState.Lflag &^= unix.ECHO
 	newState.Lflag |= unix.ICANON | unix.ISIG
 	newState.Iflag |= unix.ICRNL
-	if err := unix.IoctlSetTermios(fd, ioctlWriteTermios, &newState); err != nil {
+	if err := unix.IoctlSetTermios(int(fd), ioctlWriteTermios, &newState); err != nil {
 		return nil, err
 	}
 
 	defer func() {
-		unix.IoctlSetTermios(fd, ioctlWriteTermios, termios)
+		_ = unix.IoctlSetTermios(int(fd), ioctlWriteTermios, termios) // nolint: gosec
 	}()
 
 	return readPasswordLine(passwordReader(fd))

termmode_windows.go

@@ -1,7 +1,7 @@
 // +build windows
-//
+
 // Note the terminal manipulation functions herein are mostly stubs. They
-// don't really do anything and the hkexsh demo client depends on a wrapper
+// don't really do anything and the xs demo client depends on a wrapper
 // script using the 'stty' tool to actually set the proper mode for
 // password login and raw mode required, then restoring it upon logout/exit.
 //
@@ -12,7 +12,7 @@
 // here; the wrapper does the bare minimum to make the client workable
 // under MSYS+mintty which is what I use.
 
-package hkexsh
+package xs
 
 import (
 	"io"
@@ -27,7 +27,7 @@ type State struct {
 // MakeRaw put the terminal connected to the given file descriptor into raw
 // mode and returns the previous state of the terminal so that it can be
 // restored.
-func MakeRaw(fd int) (*State, error) {
+func MakeRaw(fd uintptr) (*State, error) {
 	// This doesn't really work. The exec.Command() runs a sub-shell
 	// so the stty mods don't affect the client process.
 	cmd := exec.Command("stty", "-echo raw")
@@ -37,13 +37,13 @@ func MakeRaw(fd int) (*State, error) {
 
 // GetState returns the current state of a terminal which may be useful to
 // restore the terminal after a signal.
-func GetState(fd int) (*State, error) {
+func GetState(fd uintptr) (*State, error) {
 	return &State{}, nil
 }
 
 // Restore restores the terminal connected to the given file descriptor to a
 // previous state.
-func Restore(fd int, state *State) error {
+func Restore(fd uintptr, state *State) error {
 	cmd := exec.Command("stty", "echo cooked")
 	cmd.Run()
 	return nil
@@ -52,7 +52,7 @@ func Restore(fd int, state *State) error {
 // ReadPassword reads a line of input from a terminal without local echo.  This
 // is commonly used for inputting passwords and other sensitive data. The slice
 // returned does not include the \n.
-func ReadPassword(fd int) ([]byte, error) {
+func ReadPassword(fd uintptr) ([]byte, error) {
 	return readPasswordLine(passwordReader(fd))
 }
 

xs/Makefile

@@ -0,0 +1,18 @@
+.PHONY: clean all vis lint
+
+EXTPKGS = bytes,errors,flag,fmt,internal,io,log,net,os,path,runtime,time,strings,sync,syscall,binary,encoding
+EXE = $(notdir $(shell pwd))
+
+all:
+	echo "BUILDOPTS:" $(BUILDOPTS)
+	go build $(BUILDOPTS) .
+
+clean:
+	$(RM) $(EXE) $(EXE).exe
+
+vis:
+	go-callvis -file xs-vis -format png -ignore $(EXTPKGS) -group pkg,type .
+	../fixup-gv.sh xs.go && cat xs-vis.gv | dot -Tpng -oxs-vis-fixedup.png
+
+lint:
+	-golangci-lint run

xs/mintty_wrapper.sh

@@ -27,6 +27,13 @@ trap cleanup EXIT ERR
 cleanup() {
   stty sane
 }
-  
+
-stty -echo raw icrnl
+me="$(basename "$(test -L "$0" && readlink "$0" || echo "$0")")"
-./hkexsh $@
+
+if [ ${1}x == "-hx" ]; then
+  _${me} -h
+else
+  stty -echo raw icrnl
+  _${me} $@
+fi
+

xs/termsize_unix.go

@@ -0,0 +1,37 @@
+// +build linux freebsd
+
+package main
+
+import (
+	"fmt"
+	"log"
+	"os"
+	"os/signal"
+	"syscall"
+
+	"blitter.com/go/xs/xsnet"
+)
+
+// Handle pty resizes (notify server side)
+func handleTermResizes(conn *xsnet.Conn) {
+	ch := make(chan os.Signal, 1)
+	signal.Notify(ch, syscall.SIGWINCH)
+	wg.Add(1)
+	// #gv:s/label=\"handleTermResizes\$1\"/label=\"resizeHandler\"/
+	go func() {
+		defer wg.Done()
+
+		for range ch {
+			// Query client's term size so we can communicate it to server
+			// pty after interactive session starts
+			cols, rows, err := GetSize()
+			log.Printf("[rows %v cols %v]\n", rows, cols)
+			if err != nil {
+				log.Println(err)
+			}
+			termSzPacket := fmt.Sprintf("%d %d", rows, cols)
+			conn.WritePacket([]byte(termSzPacket), xsnet.CSOTermSize) // nolint: errcheck,gosec
+		}
+	}()
+	ch <- syscall.SIGWINCH // Initial resize.
+}

xs/termsize_windows.go

@@ -0,0 +1,65 @@
+// +build windows
+package main
+
+import (
+	"fmt"
+	"log"
+	"time"
+
+	"blitter.com/go/xs/xsnet"
+)
+
+// Handle pty resizes (notify server side)
+func handleTermResizes(conn *xsnet.Conn) {
+	var hasStty bool
+	curCols, curRows := 0, 0
+	_, _, err := GetSize()
+	// The above may fail if user doesn't have msys 'stty' util
+	// in PATH. GetSize() will log.Error() once here
+	if err != nil {
+		fmt.Println("[1st GetSize:", err, "]")
+		hasStty = false
+	} else {
+		hasStty = true
+	}
+
+	ch := make(chan bool, 1)
+
+	if hasStty {
+		wg.Add(1)
+		go func() {
+			defer wg.Done()
+			for {
+				ch <- true
+				time.Sleep(1 * time.Second)
+			}
+		}()
+	}
+
+	wg.Add(1)
+	go func() {
+		defer wg.Done()
+
+		rows := 0
+		cols := 0
+		for range ch {
+			// Query client's term size so we can communicate it to server
+			// pty after interactive session starts
+			cols, rows, err = GetSize()
+			if err == nil {
+			} else {
+				fmt.Println("[GetSize:", err, "]")
+			}
+			if (curRows != rows) || (curCols != curCols) {
+				curRows = rows
+				curCols = cols
+				if err != nil {
+					log.Println(err)
+				}
+				termSzPacket := fmt.Sprintf("%d %d", curRows, curCols)
+				conn.WritePacket([]byte(termSzPacket), xsnet.CSOTermSize)
+			}
+		}
+	}()
+	ch <- true // Initial resize
+}

xs/xs-vis.gv

@@ -0,0 +1,549 @@
+digraph gocallvis {
+    label="blitter.com/go/xs/xs";
+    labeljust="l";
+    fontname="Arial";
+    fontsize="14";
+    rankdir="LR";
+    bgcolor="lightgray";
+    style="solid";
+    penwidth="0.5";
+    pad="0.0";
+    nodesep="0.35";
+
+    node [shape="ellipse" style="filled" fillcolor="honeydew" fontname="Verdana" penwidth="1.0" margin="0.05,0.0"];
+    edge [minlen="2"]
+
+    subgraph "cluster_focus" {
+        bgcolor="#e6ecfa";
+label="main";
+labelloc="t";
+labeljust="c";
+fontsize="18";
+        
+        "blitter.com/go/xs/xs.reqTunnel" [ fillcolor="lightblue" label="reqTunnel" penwidth="0.5" ]
+        "blitter.com/go/xs/xs.launchTuns" [ label="launchTuns" penwidth="0.5" fillcolor="lightblue" ]
+        "blitter.com/go/xs/xs.main$3" [ fillcolor="lightblue" label="main$3" style="dotted,filled" ]
+        "blitter.com/go/xs/xs.doCopyMode" [ fillcolor="lightblue" label="doCopyMode" penwidth="0.5" ]
+        "blitter.com/go/xs/xs.copyBuffer" [ fillcolor="lightblue" label="copyBuffer" penwidth="0.5" ]
+        "blitter.com/go/xs/xs.copyBuffer$1" [ label="copyBuffer$1" style="dotted,filled" fillcolor="lightblue" ]
+        "blitter.com/go/xs/xs.copyBuffer$2" [ label="copyBuffer$2" style="dotted,filled" fillcolor="lightblue" ]
+        "blitter.com/go/xs/xs.copyBuffer$3" [ fillcolor="lightblue" label="copyBuffer$3" style="dotted,filled" ]
+        "blitter.com/go/xs/xs.Copy" [ label="Copy" penwidth="1.5" fillcolor="lightblue" ]
+        "blitter.com/go/xs/xs.doShellMode$1" [ fillcolor="lightblue" label="shellRemoteToStdin" style="dotted,filled" ]
+        "blitter.com/go/xs/xs.doShellMode$1$1" [ fillcolor="lightblue" label="doShellMode$1$1" style="dotted,filled" ]
+        "blitter.com/go/xs/xs.exitWithStatus" [ fillcolor="lightblue" label="exitWithStatus" penwidth="0.5" ]
+        "blitter.com/go/xs/xs.doShellMode" [ label="doShellMode" penwidth="0.5" fillcolor="lightblue" ]
+        "blitter.com/go/xs/xs.handleTermResizes$1" [ fillcolor="lightblue" label="handleTermResizes$1" style="dotted,filled" ]
+        "blitter.com/go/xs/xs.GetSize" [ fillcolor="lightblue" label="GetSize" penwidth="1.5" ]
+        "blitter.com/go/xs/xs.handleTermResizes" [ label="handleTermResizes" penwidth="0.5" fillcolor="lightblue" ]
+        "blitter.com/go/xs/xs.doShellMode$2$1" [ fillcolor="lightblue" label="doShellMode$2$1" style="dotted,filled" ]
+        "blitter.com/go/xs/xs.doShellMode$2" [ fillcolor="lightblue" label="shellStdinToRemote" style="dotted,filled" ]
+        "blitter.com/go/xs/xs.sendSessionParams" [ fillcolor="lightblue" label="sendSessionParams" penwidth="0.5" ]
+        "blitter.com/go/xs/xs.main" [ label="main" penwidth="0.5" fillcolor="lightblue" ]
+        "blitter.com/go/xs/xs.parseNonSwitchArgs" [ fillcolor="lightblue" label="parseNonSwitchArgs" penwidth="0.5" ]
+        "blitter.com/go/xs/xs.main$1" [ fillcolor="lightblue" label="deferRestore" style="dotted,filled" ]
+        "blitter.com/go/xs/xs.main$2" [ fillcolor="lightblue" label="deferCloseChaff" style="dotted,filled" ]
+        "blitter.com/go/xs/xs.rejectUserMsg" [ fillcolor="lightblue" label="rejectUserMsg" penwidth="0.5" ]
+        "blitter.com/go/xs/xs.usageShell" [ fillcolor="lightblue" label="usageShell" penwidth="0.5" ]
+        "blitter.com/go/xs/xs.usageCp" [ label="usageCp" penwidth="0.5" fillcolor="lightblue" ]
+        
+        subgraph "cluster_blitter.com/go/xs" {
+        penwidth="0.8";
+style="filled";
+rank="sink";
+tooltip="package: blitter.com/go/xs";
+fontsize="16";
+fillcolor="lightyellow";
+fontname="bold";
+label="[xs]";
+URL="/?f=blitter.com/go/xs";
+        
+        "blitter.com/go/xs.Restore" [ fillcolor="moccasin" label="Restore" penwidth="1.5" ]
+        "blitter.com/go/xs.MakeRaw" [ penwidth="1.5" fillcolor="moccasin" label="MakeRaw" ]
+        "blitter.com/go/xs.ReadPassword" [ fillcolor="moccasin" label="ReadPassword" penwidth="1.5" ]
+        "blitter.com/go/xs.NewSession" [ fillcolor="moccasin" label="NewSession" penwidth="1.5" ]
+        
+        subgraph "cluster_*blitter.com/go/xs.Session" {
+        fontsize="15";
+fontcolor="#222222";
+labelloc="b";
+style="rounded,filled";
+fillcolor="wheat2";
+label="(*Session)";
+tooltip="type: *blitter.com/go/xs.Session";
+penwidth="0.5";
+        
+        "(*blitter.com/go/xs.Session).SetStatus" [ fillcolor="moccasin" label="SetStatus" penwidth="1.5" ]
+        
+    }
+
+        subgraph "cluster_blitter.com/go/xs.Session" {
+        style="rounded,filled";
+fillcolor="wheat2";
+label="(Session)";
+tooltip="type: blitter.com/go/xs.Session";
+penwidth="0.5";
+fontsize="15";
+fontcolor="#222222";
+labelloc="b";
+        
+        "(blitter.com/go/xs.Session).Cmd" [ fillcolor="moccasin" label="Cmd" penwidth="1.5" ]
+        "(blitter.com/go/xs.Session).Status" [ penwidth="1.5" fillcolor="moccasin" label="Status" ]
+        "(blitter.com/go/xs.Session).Op" [ fillcolor="moccasin" label="Op" penwidth="1.5" ]
+        "(blitter.com/go/xs.Session).Who" [ fillcolor="moccasin" label="Who" penwidth="1.5" ]
+        "(blitter.com/go/xs.Session).ConnHost" [ fillcolor="moccasin" label="ConnHost" penwidth="1.5" ]
+        "(blitter.com/go/xs.Session).TermType" [ fillcolor="moccasin" label="TermType" penwidth="1.5" ]
+        "(blitter.com/go/xs.Session).AuthCookie" [ label="AuthCookie" penwidth="1.5" fillcolor="moccasin" ]
+        
+    }
+
+    }
+
+        subgraph "cluster_blitter.com/go/xs/logger" {
+        fontsize="16";
+URL="/?f=blitter.com/go/xs/logger";
+penwidth="0.8";
+style="filled";
+fillcolor="lightyellow";
+fontname="bold";
+rank="sink";
+label="[logger]";
+tooltip="package: blitter.com/go/xs/logger";
+        
+        "blitter.com/go/xs/logger.LogDebug" [ fillcolor="moccasin" label="LogDebug" penwidth="1.5" ]
+        "blitter.com/go/xs/logger.New" [ fillcolor="moccasin" label="New" penwidth="1.5" ]
+        
+    }
+
+        subgraph "cluster_blitter.com/go/xs/spinsult" {
+        fillcolor="lightyellow";
+fontname="bold";
+label="[spinsult]";
+URL="/?f=blitter.com/go/xs/spinsult";
+tooltip="package: blitter.com/go/xs/spinsult";
+penwidth="0.8";
+fontsize="16";
+style="filled";
+rank="sink";
+        
+        "blitter.com/go/xs/spinsult.GetSentence" [ fillcolor="moccasin" label="GetSentence" penwidth="1.5" ]
+        
+    }
+
+        subgraph "cluster_blitter.com/go/xs/xsnet" {
+        penwidth="0.8";
+fillcolor="lightyellow";
+fontname="bold";
+rank="sink";
+URL="/?f=blitter.com/go/xs/xsnet";
+fontsize="16";
+style="filled";
+label="[xsnet]";
+tooltip="package: blitter.com/go/xs/xsnet";
+        
+        "blitter.com/go/xs/xsnet.Init" [ fillcolor="moccasin" label="Init" penwidth="1.5" ]
+        "blitter.com/go/xs/xsnet.Dial" [ label="Dial" penwidth="1.5" fillcolor="moccasin" ]
+        
+        subgraph "cluster_*blitter.com/go/xs/xsnet.Conn" {
+        fontcolor="#222222";
+labelloc="b";
+style="rounded,filled";
+fillcolor="wheat2";
+label="(*Conn)";
+tooltip="type: *blitter.com/go/xs/xsnet.Conn";
+penwidth="0.5";
+fontsize="15";
+        
+        "(*blitter.com/go/xs/xsnet.Conn).WritePacket" [ penwidth="1.5" fillcolor="moccasin" label="WritePacket" ]
+        "(*blitter.com/go/xs/xsnet.Conn).SetStatus" [ fillcolor="moccasin" label="SetStatus" penwidth="1.5" ]
+        "(*blitter.com/go/xs/xsnet.Conn).Close" [ penwidth="1.5" fillcolor="moccasin" label="Close" ]
+        "(*blitter.com/go/xs/xsnet.Conn).SetupChaff" [ penwidth="1.5" fillcolor="moccasin" label="SetupChaff" ]
+        "(*blitter.com/go/xs/xsnet.Conn).EnableChaff" [ fillcolor="moccasin" label="EnableChaff" penwidth="1.5" ]
+        "(*blitter.com/go/xs/xsnet.Conn).DisableChaff" [ fillcolor="moccasin" label="DisableChaff" penwidth="1.5" ]
+        "(*blitter.com/go/xs/xsnet.Conn).ShutdownChaff" [ fillcolor="moccasin" label="ShutdownChaff" penwidth="1.5" ]
+        
+    }
+
+        subgraph "cluster_blitter.com/go/xs/xsnet.Conn" {
+        labelloc="b";
+style="rounded,filled";
+fillcolor="wheat2";
+label="(Conn)";
+tooltip="type: blitter.com/go/xs/xsnet.Conn";
+penwidth="0.5";
+fontsize="15";
+fontcolor="#222222";
+        
+        "(blitter.com/go/xs/xsnet.Conn).Read" [ label="Read" penwidth="1.5" fillcolor="moccasin" ]
+        "(blitter.com/go/xs/xsnet.Conn).GetStatus" [ fillcolor="moccasin" label="GetStatus" penwidth="1.5" ]
+        "(blitter.com/go/xs/xsnet.Conn).Write" [ label="Write" penwidth="1.5" fillcolor="moccasin" ]
+        
+    }
+
+    }
+
+        subgraph "cluster_compress/flate" {
+        fontsize="16";
+fillcolor="#E0FFE1";
+label="[compress/flate]";
+URL="/?f=compress/flate";
+penwidth="0.8";
+style="filled";
+fontname="bold";
+rank="sink";
+tooltip="package: compress/flate";
+        
+        
+        subgraph "cluster_compress/flate.CorruptInputError" {
+        tooltip="type: compress/flate.CorruptInputError";
+penwidth="0.5";
+fontsize="15";
+fontcolor="#222222";
+labelloc="b";
+style="rounded,filled";
+fillcolor="#c2e3c2";
+label="(CorruptInputError)";
+        
+        "(compress/flate.CorruptInputError).Error" [ penwidth="1.5" fillcolor="#adedad" label="Error" ]
+        
+    }
+
+        subgraph "cluster_compress/flate.InternalError" {
+        fontsize="15";
+fontcolor="#222222";
+labelloc="b";
+style="rounded,filled";
+fillcolor="#c2e3c2";
+label="(InternalError)";
+tooltip="type: compress/flate.InternalError";
+penwidth="0.5";
+        
+        "(compress/flate.InternalError).Error" [ fillcolor="#adedad" label="Error" penwidth="1.5" ]
+        
+    }
+
+    }
+
+        subgraph "cluster_context" {
+        fontsize="16";
+style="filled";
+penwidth="0.8";
+fontname="bold";
+rank="sink";
+label="[context]";
+URL="/?f=context";
+tooltip="package: context";
+fillcolor="#E0FFE1";
+        
+        
+        subgraph "cluster_context.deadlineExceededError" {
+        fontsize="15";
+fontcolor="#222222";
+labelloc="b";
+style="rounded,filled";
+fillcolor="#c2e3c2";
+label="(deadlineExceededError)";
+tooltip="type: context.deadlineExceededError";
+penwidth="0.5";
+        
+        "(context.deadlineExceededError).Error" [ fillcolor="#adedad" label="Error" penwidth="1.5" ]
+        
+    }
+
+    }
+
+        subgraph "cluster_crypto/aes" {
+        style="filled";
+fillcolor="#E0FFE1";
+rank="sink";
+label="[crypto/aes]";
+penwidth="0.8";
+fontsize="16";
+fontname="bold";
+URL="/?f=crypto/aes";
+tooltip="package: crypto/aes";
+        
+        
+        subgraph "cluster_crypto/aes.KeySizeError" {
+        fontcolor="#222222";
+labelloc="b";
+style="rounded,filled";
+fillcolor="#c2e3c2";
+label="(KeySizeError)";
+tooltip="type: crypto/aes.KeySizeError";
+penwidth="0.5";
+fontsize="15";
+        
+        "(crypto/aes.KeySizeError).Error" [ fillcolor="#adedad" label="Error" penwidth="1.5" ]
+        
+    }
+
+    }
+
+        subgraph "cluster_crypto/tls" {
+        tooltip="package: crypto/tls";
+fontsize="16";
+style="filled";
+fontname="bold";
+rank="sink";
+label="[crypto/tls]";
+URL="/?f=crypto/tls";
+penwidth="0.8";
+fillcolor="#E0FFE1";
+        
+        
+        subgraph "cluster_crypto/tls.RecordHeaderError" {
+        fontcolor="#222222";
+labelloc="b";
+style="rounded,filled";
+fillcolor="#c2e3c2";
+label="(RecordHeaderError)";
+tooltip="type: crypto/tls.RecordHeaderError";
+penwidth="0.5";
+fontsize="15";
+        
+        "(crypto/tls.RecordHeaderError).Error" [ fillcolor="#adedad" label="Error" penwidth="1.5" ]
+        
+    }
+
+        subgraph "cluster_crypto/tls.alert" {
+        penwidth="0.5";
+fontsize="15";
+fontcolor="#222222";
+labelloc="b";
+style="rounded,filled";
+fillcolor="#c2e3c2";
+label="(alert)";
+tooltip="type: crypto/tls.alert";
+        
+        "(crypto/tls.alert).Error" [ fillcolor="#adedad" label="Error" penwidth="1.5" ]
+        
+    }
+
+    }
+
+        subgraph "cluster_crypto/x509" {
+        penwidth="0.8";
+tooltip="package: crypto/x509";
+fontsize="16";
+style="filled";
+fillcolor="#E0FFE1";
+fontname="bold";
+rank="sink";
+label="[crypto/x509]";
+URL="/?f=crypto/x509";
+        
+        
+        subgraph "cluster_crypto/x509.CertificateInvalidError" {
+        penwidth="0.5";
+fontsize="15";
+fontcolor="#222222";
+labelloc="b";
+style="rounded,filled";
+fillcolor="#c2e3c2";
+label="(CertificateInvalidError)";
+tooltip="type: crypto/x509.CertificateInvalidError";
+        
+        "(crypto/x509.CertificateInvalidError).Error" [ fillcolor="#adedad" label="Error" penwidth="1.5" ]
+        
+    }
+
+        subgraph "cluster_crypto/x509.HostnameError" {
+        labelloc="b";
+style="rounded,filled";
+fillcolor="#c2e3c2";
+label="(HostnameError)";
+tooltip="type: crypto/x509.HostnameError";
+penwidth="0.5";
+fontsize="15";
+fontcolor="#222222";
+        
+        "(crypto/x509.HostnameError).Error" [ fillcolor="#adedad" label="Error" penwidth="1.5" ]
+        
+    }
+
+        subgraph "cluster_crypto/x509.SystemRootsError" {
+        fontsize="15";
+fontcolor="#222222";
+labelloc="b";
+style="rounded,filled";
+fillcolor="#c2e3c2";
+label="(SystemRootsError)";
+tooltip="type: crypto/x509.SystemRootsError";
+penwidth="0.5";
+        
+        "(crypto/x509.SystemRootsError).Error" [ fillcolor="#adedad" label="Error" penwidth="1.5" ]
+        
+    }
+
+        subgraph "cluster_crypto/x509.UnhandledCriticalExtension" {
+        style="rounded,filled";
+fillcolor="#c2e3c2";
+label="(UnhandledCriticalExtension)";
+tooltip="type: crypto/x509.UnhandledCriticalExtension";
+penwidth="0.5";
+fontsize="15";
+fontcolor="#222222";
+labelloc="b";
+        
+        "(crypto/x509.UnhandledCriticalExtension).Error" [ fillcolor="#adedad" label="Error" penwidth="1.5" ]
+        
+    }
+
+        subgraph "cluster_crypto/x509.UnknownAuthorityError" {
+        style="rounded,filled";
+fillcolor="#c2e3c2";
+label="(UnknownAuthorityError)";
+tooltip="type: crypto/x509.UnknownAuthorityError";
+penwidth="0.5";
+fontsize="15";
+fontcolor="#222222";
+labelloc="b";
+        
+        "(crypto/x509.UnknownAuthorityError).Error" [ fillcolor="#adedad" label="Error" penwidth="1.5" ]
+        
+    }
+
+    }
+
+        subgraph "cluster_github.com/mattn/go-isatty" {
+        fontname="bold";
+penwidth="0.8";
+fillcolor="lightyellow";
+rank="sink";
+label="[isatty]";
+URL="/?f=github.com/mattn/go-isatty";
+tooltip="package: github.com/mattn/go-isatty";
+fontsize="16";
+style="filled";
+        
+        "github.com/mattn/go-isatty.IsTerminal" [ label="IsTerminal" penwidth="1.5" fillcolor="moccasin" ]
+        
+    }
+
+        subgraph "cluster_github.com/pkg/errors" {
+        style="filled";
+fillcolor="lightyellow";
+URL="/?f=github.com/pkg/errors";
+rank="sink";
+label="[errors]";
+tooltip="package: github.com/pkg/errors";
+penwidth="0.8";
+fontsize="16";
+fontname="bold";
+        
+        
+        subgraph "cluster_*github.com/pkg/errors.fundamental" {
+        label="(*fundamental)";
+tooltip="type: *github.com/pkg/errors.fundamental";
+penwidth="0.5";
+fontsize="15";
+fontcolor="#222222";
+labelloc="b";
+style="rounded,filled";
+fillcolor="wheat2";
+        
+        "(*github.com/pkg/errors.fundamental).Error" [ penwidth="1.5" fillcolor="moccasin" label="Error" ]
+        
+    }
+
+    }
+
+        subgraph "cluster_math/rand" {
+        penwidth="0.8";
+fillcolor="#E0FFE1";
+rank="sink";
+URL="/?f=math/rand";
+fontsize="16";
+style="filled";
+fontname="bold";
+label="[math/rand]";
+tooltip="package: math/rand";
+        
+        "math/rand.Intn" [ fillcolor="#adedad" label="Intn" penwidth="1.5" ]
+        
+    }
+
+    }
+
+    "blitter.com/go/xs/xs.reqTunnel" -> "blitter.com/go/xs/logger.LogDebug" [ color="saddlebrown" ]
+    "blitter.com/go/xs/xs.reqTunnel" -> "(*blitter.com/go/xs/xsnet.Conn).WritePacket" [ color="saddlebrown" ]
+    "blitter.com/go/xs/xs.launchTuns" -> "blitter.com/go/xs/xs.reqTunnel" [  ]
+    "blitter.com/go/xs/xs.main$3" -> "math/rand.Intn" [ color="saddlebrown" ]
+    "blitter.com/go/xs/xs.main$3" -> "(*blitter.com/go/xs/xsnet.Conn).WritePacket" [ color="saddlebrown" ]
+    "blitter.com/go/xs/xs.doCopyMode" -> "(blitter.com/go/xs.Session).Cmd" [ color="saddlebrown" ]
+    "blitter.com/go/xs/xs.doCopyMode" -> "(*blitter.com/go/xs/xsnet.Conn).WritePacket" [ color="saddlebrown" ]
+    "blitter.com/go/xs/xs.doCopyMode" -> "(blitter.com/go/xs/xsnet.Conn).Read" [ color="saddlebrown" ]
+    "blitter.com/go/xs/xs.doCopyMode" -> "(*blitter.com/go/xs/xsnet.Conn).SetStatus" [ color="saddlebrown" ]
+    "blitter.com/go/xs/xs.doCopyMode" -> "(blitter.com/go/xs/xsnet.Conn).GetStatus" [ color="saddlebrown" ]
+    "blitter.com/go/xs/xs.copyBuffer" -> "(blitter.com/go/xs/xsnet.Conn).Write" [ color="saddlebrown" style="dashed" ]
+    "blitter.com/go/xs/xs.copyBuffer" -> "blitter.com/go/xs/xs.copyBuffer$1" [ style="dashed" ]
+    "blitter.com/go/xs/xs.copyBuffer" -> "blitter.com/go/xs/xs.copyBuffer$2" [ style="dashed" ]
+    "blitter.com/go/xs/xs.copyBuffer" -> "blitter.com/go/xs/xs.copyBuffer$3" [ style="dashed" ]
+    "blitter.com/go/xs/xs.Copy" -> "blitter.com/go/xs/xs.copyBuffer" [  ]
+    "blitter.com/go/xs/xs.doShellMode$1" -> "blitter.com/go/xs/xs.doShellMode$1$1" [ arrowhead="normalnoneodiamond" ]
+    "blitter.com/go/xs/xs.doShellMode$1" -> "blitter.com/go/xs.Restore" [ color="saddlebrown" ]
+    "blitter.com/go/xs/xs.doShellMode$1" -> "(blitter.com/go/xs/xsnet.Conn).GetStatus" [ color="saddlebrown" ]
+    "blitter.com/go/xs/xs.doShellMode$1" -> "(*blitter.com/go/xs.Session).SetStatus" [ color="saddlebrown" ]
+    "blitter.com/go/xs/xs.doShellMode$1" -> "(blitter.com/go/xs.Session).Status" [ color="saddlebrown" ]
+    "blitter.com/go/xs/xs.doShellMode$1" -> "blitter.com/go/xs/xs.exitWithStatus" [  ]
+    "blitter.com/go/xs/xs.doShellMode$1" -> "(crypto/x509.CertificateInvalidError).Error" [ style="dashed" color="saddlebrown" ]
+    "blitter.com/go/xs/xs.doShellMode$1" -> "(crypto/aes.KeySizeError).Error" [ style="dashed" color="saddlebrown" ]
+    "blitter.com/go/xs/xs.doShellMode$1" -> "(crypto/x509.HostnameError).Error" [ color="saddlebrown" style="dashed" ]
+    "blitter.com/go/xs/xs.doShellMode$1" -> "(crypto/x509.UnhandledCriticalExtension).Error" [ style="dashed" color="saddlebrown" ]
+    "blitter.com/go/xs/xs.doShellMode$1" -> "(context.deadlineExceededError).Error" [ style="dashed" color="saddlebrown" ]
+    "blitter.com/go/xs/xs.doShellMode$1" -> "(compress/flate.CorruptInputError).Error" [ style="dashed" color="saddlebrown" ]
+    "blitter.com/go/xs/xs.doShellMode$1" -> "(crypto/tls.RecordHeaderError).Error" [ style="dashed" color="saddlebrown" ]
+    "blitter.com/go/xs/xs.doShellMode$1" -> "(crypto/x509.UnknownAuthorityError).Error" [ style="dashed" color="saddlebrown" ]
+    "blitter.com/go/xs/xs.doShellMode$1" -> "(crypto/x509.SystemRootsError).Error" [ style="dashed" color="saddlebrown" ]
+    "blitter.com/go/xs/xs.doShellMode$1" -> "(compress/flate.InternalError).Error" [ style="dashed" color="saddlebrown" ]
+    "blitter.com/go/xs/xs.doShellMode$1" -> "(crypto/tls.alert).Error" [ style="dashed" color="saddlebrown" ]
+    "blitter.com/go/xs/xs.doShellMode$1" -> "(*github.com/pkg/errors.fundamental).Error" [ style="dashed" color="saddlebrown" ]
+    "blitter.com/go/xs/xs.doShellMode" -> "blitter.com/go/xs/xs.doShellMode$1" [ arrowhead="normalnoneodot" ]
+    "blitter.com/go/xs/xs.handleTermResizes$1" -> "blitter.com/go/xs/xs.GetSize" [  ]
+    "blitter.com/go/xs/xs.handleTermResizes$1" -> "(*blitter.com/go/xs/xsnet.Conn).WritePacket" [ color="saddlebrown" ]
+    "blitter.com/go/xs/xs.handleTermResizes" -> "blitter.com/go/xs/xs.handleTermResizes$1" [ arrowhead="normalnoneodot" ]
+    "blitter.com/go/xs/xs.doShellMode" -> "blitter.com/go/xs/xs.handleTermResizes" [  ]
+    "blitter.com/go/xs/xs.doShellMode$2$1" -> "blitter.com/go/xs/xs.Copy" [  ]
+    "blitter.com/go/xs/xs.doShellMode$2" -> "blitter.com/go/xs/xs.doShellMode$2$1" [  ]
+    "blitter.com/go/xs/xs.doShellMode$2" -> "blitter.com/go/xs.Restore" [ color="saddlebrown" ]
+    "blitter.com/go/xs/xs.doShellMode$2" -> "blitter.com/go/xs/xs.exitWithStatus" [  ]
+    "blitter.com/go/xs/xs.doShellMode" -> "blitter.com/go/xs/xs.doShellMode$2" [ arrowhead="normalnoneodot" ]
+    "blitter.com/go/xs/xs.sendSessionParams" -> "(blitter.com/go/xs.Session).Op" [ color="saddlebrown" ]
+    "blitter.com/go/xs/xs.sendSessionParams" -> "(blitter.com/go/xs.Session).Who" [ color="saddlebrown" ]
+    "blitter.com/go/xs/xs.sendSessionParams" -> "(blitter.com/go/xs.Session).ConnHost" [ color="saddlebrown" ]
+    "blitter.com/go/xs/xs.sendSessionParams" -> "(blitter.com/go/xs.Session).TermType" [ color="saddlebrown" ]
+    "blitter.com/go/xs/xs.sendSessionParams" -> "(blitter.com/go/xs.Session).Cmd" [ color="saddlebrown" ]
+    "blitter.com/go/xs/xs.sendSessionParams" -> "(blitter.com/go/xs.Session).AuthCookie" [ color="saddlebrown" ]
+    "blitter.com/go/xs/xs.sendSessionParams" -> "(blitter.com/go/xs/xsnet.Conn).Write" [ style="dashed" color="saddlebrown" ]
+    "blitter.com/go/xs/xs.main" -> "blitter.com/go/xs/xs.parseNonSwitchArgs" [  ]
+    "blitter.com/go/xs/xs.main" -> "blitter.com/go/xs/xs.main$1" [ arrowhead="normalnoneodot" ]
+    "blitter.com/go/xs/xs.main" -> "blitter.com/go/xs/xs.exitWithStatus" [  ]
+    "blitter.com/go/xs/xs.main" -> "blitter.com/go/xs/logger.New" [ color="saddlebrown" ]
+    "blitter.com/go/xs/xs.main" -> "blitter.com/go/xs/xsnet.Init" [ color="saddlebrown" ]
+    "blitter.com/go/xs/xs.main" -> "blitter.com/go/xs/xsnet.Dial" [ color="saddlebrown" ]
+    "blitter.com/go/xs/xs.main" -> "(*blitter.com/go/xs/xsnet.Conn).Close" [ arrowhead="normalnoneodiamond" color="saddlebrown" ]
+    "blitter.com/go/xs/xs.main" -> "github.com/mattn/go-isatty.IsTerminal" [ color="saddlebrown" ]
+    "blitter.com/go/xs/xs.main" -> "blitter.com/go/xs.MakeRaw" [ color="saddlebrown" ]
+    "blitter.com/go/xs/xs.main$2" -> "blitter.com/go/xs.Restore" [ color="saddlebrown" ]
+    "blitter.com/go/xs/xs.main" -> "blitter.com/go/xs/xs.main$2" [ arrowhead="normalnoneodiamond" ]
+    "blitter.com/go/xs/xs.main" -> "blitter.com/go/xs.ReadPassword" [ color="saddlebrown" ]
+    "blitter.com/go/xs/xs.main" -> "blitter.com/go/xs.NewSession" [ color="saddlebrown" ]
+    "blitter.com/go/xs/xs.main" -> "blitter.com/go/xs/xs.sendSessionParams" [  ]
+    "blitter.com/go/xs/xs.main" -> "(blitter.com/go/xs/xsnet.Conn).Read" [ color="saddlebrown" ]
+    "blitter.com/go/xs/xs.main" -> "(*blitter.com/go/xs.Session).SetStatus" [ color="saddlebrown" ]
+    "blitter.com/go/xs/xs.rejectUserMsg" -> "blitter.com/go/xs/spinsult.GetSentence" [ color="saddlebrown" ]
+    "blitter.com/go/xs/xs.main" -> "blitter.com/go/xs/xs.rejectUserMsg" [  ]
+    "blitter.com/go/xs/xs.main" -> "(*blitter.com/go/xs/xsnet.Conn).SetupChaff" [ color="saddlebrown" ]
+    "blitter.com/go/xs/xs.main" -> "(*blitter.com/go/xs/xsnet.Conn).EnableChaff" [ color="saddlebrown" ]
+    "blitter.com/go/xs/xs.main" -> "(*blitter.com/go/xs/xsnet.Conn).DisableChaff" [ arrowhead="normalnoneodiamond" color="saddlebrown" ]
+    "blitter.com/go/xs/xs.main" -> "(*blitter.com/go/xs/xsnet.Conn).ShutdownChaff" [ arrowhead="normalnoneodiamond" color="saddlebrown" ]
+    "blitter.com/go/xs/xs.main" -> "blitter.com/go/xs/xs.main$3" [ arrowhead="normalnoneodot" ]
+    "blitter.com/go/xs/xs.main" -> "blitter.com/go/xs/xs.launchTuns" [  ]
+    "blitter.com/go/xs/xs.main" -> "blitter.com/go/xs/xs.doShellMode" [  ]
+    "blitter.com/go/xs/xs.main" -> "(blitter.com/go/xs.Session).Status" [ color="saddlebrown" ]
+    "blitter.com/go/xs/xs.main" -> "blitter.com/go/xs/xs.doCopyMode" [  ]
+    "blitter.com/go/xs/xs.main" -> "blitter.com/go/xs.Restore" [ color="saddlebrown" ]
+    "blitter.com/go/xs/xs.main" -> "blitter.com/go/xs/xs.usageShell" [ style="dashed" ]
+    "blitter.com/go/xs/xs.main" -> "blitter.com/go/xs/xs.usageCp" [ style="dashed" ]
+}

xsd.initrc

@@ -0,0 +1,39 @@
+#!/sbin/openrc-run
+
+SVCNAME=xsd
+XSD_PIDFILE=/var/run/xsd.pid
+XSD_USER=root
+XSD_HOME=/var/run
+INST_PREFIX=/usr/local
+COMMAND=$INST_PREFIX/sbin/xsd
+ARGS="-L"
+
+depend() {
+    need net
+    use dns logger
+}
+
+checkconfig() {
+    if [ ! -f "$COMMAND" ] ; then
+        eerror "$COMMAND not installed" || return 1
+    fi
+    return 0
+}
+
+start() {
+    checkconfig || return 1
+
+    ebegin "Starting ${SVCNAME}"
+    start-stop-daemon \
+        -d ${XSD_HOME} \
+        --make-pidfile --pidfile ${XSD_PIDFILE} \
+        --start --quiet --background \
+        --exec "${COMMAND}" -- "${ARGS}"
+    eend $?
+}
+
+stop() {
+    ebegin "Stopping ${SVCNAME}"
+    start-stop-daemon --stop --quiet --pidfile $XSD_PIDFILE
+    eend $?
+}

xsd.sysvrc

@@ -0,0 +1,162 @@
+#! /bin/sh
+
+### BEGIN INIT INFO
+# Provides:		xsd
+# Required-Start:	$remote_fs $syslog
+# Required-Stop:	$remote_fs $syslog
+# Default-Start:	2 3 4 5
+# Default-Stop:		
+# Short-Description:	eXperimental Shell Daemon
+### END INIT INFO
+
+set -e
+
+# /etc/init.d/xsd: start and stop the eXperimental "secure" Shell Daemon
+
+test -x /usr/local/sbin/xsd || exit 0
+( /usr/local/sbin/xsd -h 2>&1 | grep -q chaff ) 2>/dev/null || exit 0
+
+umask 022
+
+#if test -f /etc/default/ssh; then
+#    . /etc/default/ssh
+#fi
+
+. /lib/lsb/init-functions
+
+if [ -n "$2" ]; then
+    XSD_OPTS="$XSD_OPTS $2"
+fi
+
+# Are we running from init?
+run_by_init() {
+    ([ "$previous" ] && [ "$runlevel" ]) || [ "$runlevel" = S ]
+}
+
+check_for_no_start() {
+    # forget it if we're trying to start, and /etc/xsd_not_to_be_run exists
+    if [ -e /etc/xsd_not_to_be_run ]; then 
+	if [ "$1" = log_end_msg ]; then
+	    log_end_msg 0 || true
+	fi
+	if ! run_by_init; then
+	    log_action_msg "eXperimental Shell Daemon not in use (/etc/xsd_not_to_be_run)" || true
+	fi
+	exit 0
+    fi
+}
+
+check_dev_null() {
+    if [ ! -c /dev/null ]; then
+	if [ "$1" = log_end_msg ]; then
+	    log_end_msg 1 || true
+	fi
+	if ! run_by_init; then
+	    log_action_msg "/dev/null is not a character device!" || true
+	fi
+	exit 1
+    fi
+}
+
+#check_privsep_dir() {
+#    # Create the PrivSep empty dir if necessary
+#    if [ ! -d /run/sshd ]; then
+#	mkdir /run/sshd
+#	chmod 0755 /run/sshd
+#    fi
+#}
+
+#check_config() {
+#    if [ ! -e /etc/xsd_not_to_be_run ]; then
+#	/usr/local/sbin/xsd $XSD_OPTS -t || exit 1
+#    fi
+#}
+
+export PATH="${PATH:+$PATH:}/usr/local/sbin:/usr/sbin:/sbin"
+
+case "$1" in
+  start)
+	#check_privsep_dir
+	check_for_no_start
+	check_dev_null
+	log_daemon_msg "Starting eXperimental Shell Daemon" "xsd" || true
+	if start-stop-daemon --start -b --quiet --oknodo --chuid 0:0 --exec /usr/local/sbin/xsd -- $XSD_OPTS; then
+	    log_end_msg 0 || true
+	else
+	    log_end_msg 1 || true
+	fi
+	;;
+  stop)
+	log_daemon_msg "Stopping eXperimental Shell Daemon" "xsd" || true
+	if start-stop-daemon --stop --quiet --oknodo --exec /usr/local/sbin/xsd; then
+	    log_end_msg 0 || true
+	else
+	    log_end_msg 1 || true
+	fi
+	;;
+
+  reload|force-reload)
+	check_for_no_start
+	#check_config
+	log_daemon_msg "Reloading eXperimental Shell Daemon's configuration" "xsd" || true
+	if start-stop-daemon --stop --signal 1 --quiet --oknodo --exec /usr/local/sbin/xsd; then
+	    log_end_msg 0 || true
+	else
+	    log_end_msg 1 || true
+	fi
+	;;
+
+  restart)
+	#check_privsep_dir
+	#check_config
+	log_daemon_msg "Restarting eXperimental Shell Daemon" "xsd" || true
+	start-stop-daemon --stop --quiet --oknodo --retry 30 --exec /usr/local/sbin/xsd
+	check_for_no_start log_end_msg
+	check_dev_null log_end_msg
+	if start-stop-daemon --start -b --quiet --oknodo --chuid 0:0 --exec /usr/local/sbin/xsd -- $XSD_OPTS; then
+	    log_end_msg 0 || true
+	else
+	    log_end_msg 1 || true
+	fi
+	;;
+
+  try-restart)
+	#check_privsep_dir
+	#check_config
+	log_daemon_msg "Restarting eXperimental Shell Daemon" "xsd" || true
+	RET=0
+	start-stop-daemon --stop --quiet --retry 30 --exec /usr/local/sbin/xsd || RET="$?"
+	case $RET in
+	    0)
+		# old daemon stopped
+		check_for_no_start log_end_msg
+		check_dev_null log_end_msg
+		if start-stop-daemon --start -b --quiet --oknodo --chuid 0:0 --exec /usr/local/sbin/xsd -- $XSD_OPTS; then
+		    log_end_msg 0 || true
+		else
+		    log_end_msg 1 || true
+		fi
+		;;
+	    1)
+		# daemon not running
+		log_progress_msg "(not running)" || true
+		log_end_msg 0 || true
+		;;
+	    *)
+		# failed to stop
+		log_progress_msg "(failed to stop)" || true
+		log_end_msg 1 || true
+		;;
+	esac
+	;;
+
+  status)
+	status_of_proc -p /run/xsd.pid /usr/local/sbin/xsd xsd && exit 0 || exit $?
+	;;
+
+  *)
+	log_action_msg "Usage: /etc/init.d/xsd {start|stop|reload|force-reload|restart|try-restart|status}" || true
+	exit 1
+esac
+
+exit 0

xsd/Makefile

@@ -0,0 +1,18 @@
+.PHONY: clean all vis lint
+
+EXTPKGS = binary,bytes,crypto,encoding,errors,flag,fmt,internal,io,log,net,os,path,runtime,time,strings,sync,syscall
+EXE = $(notdir $(shell pwd))
+
+all:
+	go build $(BUILDOPTS) .
+
+clean:
+	$(RM) $(EXE) $(EXE).exe
+
+vis:
+	go-callvis -file xsd-vis -format png -ignore $(EXTPKGS) -group pkg,type .
+	../fixup-gv.sh xsd.go && cat xsd-vis.gv | dot -Tpng -oxsd-vis-fixedup.png
+
+lint:
+	-golangci-lint run
+

xsd/xsd-vis.gv

@@ -0,0 +1,347 @@
+digraph gocallvis {
+    label="blitter.com/go/xs/xsd";
+    labeljust="l";
+    fontname="Arial";
+    fontsize="14";
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+        "(*blitter.com/go/xs.Session).ClearAuthCookie" [ fillcolor="moccasin" label="ClearAuthCookie" penwidth="1.5" ]
+        
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+        
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+
+    }
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+        
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+        "(*blitter.com/go/xs/xsnet.Conn).SetupChaff" [ penwidth="1.5" fillcolor="moccasin" label="SetupChaff" ]
+        
+    }
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+        
+    }
+
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+        
+    }
+
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+        
+    }
+
+    }
+
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+        
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+        
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+        
+    }
+
+    }
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+    "blitter.com/go/xs/xsd.main$2" -> "blitter.com/go/xs/xsd.runClientToServerCopyAs" [  ]
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+    "blitter.com/go/xs/xsd.main$2" -> "blitter.com/go/xs/xsd.runServerToClientCopyAs" [  ]
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+    "blitter.com/go/xs/xsd.main" -> "blitter.com/go/xs/xsnet.Init" [ color="saddlebrown" ]
+    "blitter.com/go/xs/xsd.main$1" -> "blitter.com/go/xs/logger.LogNotice" [ color="saddlebrown" ]
+    "blitter.com/go/xs/xsd.main" -> "blitter.com/go/xs/xsd.main$1" [ arrowhead="normalnoneodot" ]
+    "blitter.com/go/xs/xsd.main" -> "blitter.com/go/xs/xsnet.Listen" [ color="saddlebrown" ]
+    "blitter.com/go/xs/xsd.main" -> "(blitter.com/go/xs/xsnet.HKExListener).Close" [ arrowhead="normalnoneodiamond" color="saddlebrown" ]
+    "blitter.com/go/xs/xsd.main" -> "(*blitter.com/go/xs/xsnet.HKExListener).Accept" [ color="saddlebrown" ]
+    "blitter.com/go/xs/xsd.main" -> "(*blitter.com/go/xs/xsnet.Conn).SetupChaff" [ color="saddlebrown" ]
+    "blitter.com/go/xs/xsd.main" -> "blitter.com/go/xs/xsd.main$2" [ arrowhead="normalnoneodot" ]
+}

xsd/xsd.go

@@ -0,0 +1,849 @@
+// xsd server
+//
+// Copyright (c) 2017-2020 Russell Magee
+// Licensed under the terms of the MIT license (see LICENSE.mit in this
+// distribution)
+//
+// golang implementation by Russ Magee (rmagee_at_gmail.com)
+package main
+
+import (
+	"bytes"
+	"crypto/rand"
+	"encoding/binary"
+	"encoding/hex"
+	"errors"
+	"flag"
+	"fmt"
+	"io"
+	"io/ioutil"
+	"log"
+	"os"
+	"os/exec"
+	"os/signal"
+	"os/user"
+	"path"
+	"strings"
+	"sync"
+	"syscall"
+	"time"
+	"unsafe"
+
+	"blitter.com/go/goutmp"
+	xs "blitter.com/go/xs"
+	"blitter.com/go/xs/logger"
+	"blitter.com/go/xs/xsnet"
+	"github.com/creack/pty"
+)
+
+var (
+	version   string
+	gitCommit string // set in -ldflags by build
+
+	useSysLogin bool
+	kcpMode     string // set to a valid KCP BlockCrypt alg tag to use rather than TCP
+
+	// Log - syslog output (with no -d)
+	Log *logger.Writer
+)
+
+func ioctl(fd, request, argp uintptr) error {
+	if _, _, e := syscall.Syscall6(syscall.SYS_IOCTL, fd, request, argp, 0, 0, 0); e != 0 {
+		return e
+	}
+	return nil
+}
+
+func ptsName(fd uintptr) (string, error) {
+	var n uintptr
+	err := ioctl(fd, syscall.TIOCGPTN, uintptr(unsafe.Pointer(&n)))
+	if err != nil {
+		return "", err
+	}
+	return fmt.Sprintf("/dev/pts/%d", n), nil
+}
+
+/* -------------------------------------------------------------- */
+// Perform a client->server copy
+func runClientToServerCopyAs(who, ttype string, conn *xsnet.Conn, fpath string, chaffing bool) (exitStatus uint32, err error) {
+	u, _ := user.Lookup(who) // nolint: gosec
+	var uid, gid uint32
+	fmt.Sscanf(u.Uid, "%d", &uid) // nolint: gosec,errcheck
+	fmt.Sscanf(u.Gid, "%d", &gid) // nolint: gosec,errcheck
+	log.Println("uid:", uid, "gid:", gid)
+
+	// Need to clear server's env and set key vars of the
+	// target user. This isn't perfect (TERM doesn't seem to
+	// work 100%; ANSI/xterm colour isn't working even
+	// if we set "xterm" or "ansi" here; and line count
+	// reported by 'stty -a' defaults to 24 regardless
+	// of client shell window used to run client.
+	// Investigate -- rlm 2018-01-26)
+	os.Clearenv()
+	os.Setenv("HOME", u.HomeDir) // nolint: gosec,errcheck
+	os.Setenv("TERM", ttype)     // nolint: gosec,errcheck
+	os.Setenv("XS_SESSION", "1")     // nolint: gosec,errcheck
+
+	var c *exec.Cmd
+	cmdName := xs.GetTool("tar")
+
+	var destDir string
+	if path.IsAbs(fpath) {
+		destDir = fpath
+	} else {
+		destDir = path.Join(u.HomeDir, fpath)
+	}
+
+	cmdArgs := []string{"-xz", "-C", destDir}
+
+	// NOTE the lack of quotes around --xform option's sed expression.
+	// When args are passed in exec() format, no quoting is required
+	// (as this isn't input from a shell) (right? -rlm 20180823)
+	//cmdArgs := []string{"-x", "-C", destDir, `--xform=s#.*/\(.*\)#\1#`}
+	fmt.Println(cmdName, cmdArgs)
+	c = exec.Command(cmdName, cmdArgs...) // nolint: gosec
+
+	c.Dir = destDir
+
+	//If os.Clearenv() isn't called by server above these will be seen in the
+	//client's session env.
+	//c.Env = []string{"HOME=" + u.HomeDir, "SUDO_GID=", "SUDO_UID=", "SUDO_USER=", "SUDO_COMMAND=", "MAIL=", "LOGNAME="+who}
+	//c.Dir = u.HomeDir
+	c.SysProcAttr = &syscall.SysProcAttr{}
+	c.SysProcAttr.Credential = &syscall.Credential{Uid: uid, Gid: gid}
+	c.Stdin = conn
+	c.Stdout = os.Stdout
+	c.Stderr = os.Stderr
+
+	if chaffing {
+		conn.EnableChaff()
+	}
+	defer conn.DisableChaff()
+	defer conn.ShutdownChaff()
+
+	// Start the command (no pty)
+	log.Printf("[%v %v]\n", cmdName, cmdArgs)
+	err = c.Start() // returns immediately
+	/////////////
+	// NOTE: There is, apparently, a bug in Go stdlib here. Start()
+	// can actually return immediately, on a command which *does*
+	// start but exits quickly, with c.Wait() error
+	// "c.Wait status: exec: not started".
+	// As in this example, attempting a client->server copy to
+	// a nonexistent remote dir (it's tar exiting right away, exitStatus
+	// 2, stderr
+	// /bin/tar -xz -C /home/someuser/nosuchdir
+	// stderr: fork/exec /bin/tar: no such file or directory
+	//
+	// In this case, c.Wait() won't give us the real
+	// exit status (is it lost?).
+	/////////////
+	if err != nil {
+		log.Println("cmd exited immediately. Cannot get cmd.Wait().ExitStatus()")
+		err = errors.New("cmd exited prematurely")
+		//exitStatus = uint32(254)
+		exitStatus = xsnet.CSEExecFail
+	} else {
+		if err := c.Wait(); err != nil {
+			//fmt.Println("*** c.Wait() done ***")
+			if exiterr, ok := err.(*exec.ExitError); ok {
+				// The program has exited with an exit code != 0
+
+				// This works on both Unix and Windows. Although package
+				// syscall is generally platform dependent, WaitStatus is
+				// defined for both Unix and Windows and in both cases has
+				// an ExitStatus() method with the same signature.
+				if status, ok := exiterr.Sys().(syscall.WaitStatus); ok {
+					exitStatus = uint32(status.ExitStatus())
+					//err = errors.New("cmd returned nonzero status")
+					log.Printf("Exit Status: %d\n", exitStatus)
+				}
+			}
+		}
+		log.Println("*** client->server cp finished ***")
+	}
+	return
+}
+
+// Perform a server->client copy
+func runServerToClientCopyAs(who, ttype string, conn *xsnet.Conn, srcPath string, chaffing bool) (exitStatus uint32, err error) {
+	u, err := user.Lookup(who)
+	if err != nil {
+		exitStatus = 1
+		return
+	}
+	var uid, gid uint32
+	_, _ = fmt.Sscanf(u.Uid, "%d", &uid) // nolint: gosec
+	_, _ = fmt.Sscanf(u.Gid, "%d", &gid) // nolint: gosec
+	log.Println("uid:", uid, "gid:", gid)
+
+	// Need to clear server's env and set key vars of the
+	// target user. This isn't perfect (TERM doesn't seem to
+	// work 100%; ANSI/xterm colour isn't working even
+	// if we set "xterm" or "ansi" here; and line count
+	// reported by 'stty -a' defaults to 24 regardless
+	// of client shell window used to run client.
+	// Investigate -- rlm 2018-01-26)
+	os.Clearenv()
+	_ = os.Setenv("HOME", u.HomeDir) // nolint: gosec
+	_ = os.Setenv("TERM", ttype)     // nolint: gosec
+	_ = os.Setenv("XS_SESSION", "1")     // nolint: gosec
+
+	var c *exec.Cmd
+	cmdName := xs.GetTool("tar")
+	if !path.IsAbs(srcPath) {
+		srcPath = fmt.Sprintf("%s%c%s", u.HomeDir, os.PathSeparator, srcPath)
+	}
+
+	srcDir, srcBase := path.Split(srcPath)
+	cmdArgs := []string{"-cz", "-C", srcDir, "-f", "-", srcBase}
+
+	c = exec.Command(cmdName, cmdArgs...) // nolint: gosec
+
+	//If os.Clearenv() isn't called by server above these will be seen in the
+	//client's session env.
+	//c.Env = []string{"HOME=" + u.HomeDir, "SUDO_GID=", "SUDO_UID=", "SUDO_USER=", "SUDO_COMMAND=", "MAIL=", "LOGNAME="+who}
+	c.Dir = u.HomeDir
+	c.SysProcAttr = &syscall.SysProcAttr{}
+	c.SysProcAttr.Credential = &syscall.Credential{Uid: uid, Gid: gid}
+	c.Stdout = conn
+	// Stderr sinkholing (or buffering to something other than stdout)
+	// is important. Any extraneous output to tarpipe messes up remote
+	// side as it's expecting pure tar data.
+	// (For example, if user specifies abs paths, tar outputs
+	// "Removing leading '/' from path names")
+	stdErrBuffer := new(bytes.Buffer)
+	c.Stderr = stdErrBuffer
+	//c.Stderr = nil
+
+	if chaffing {
+		conn.EnableChaff()
+	}
+	//defer conn.Close()
+	defer conn.DisableChaff()
+	defer conn.ShutdownChaff()
+
+	// Start the command (no pty)
+	log.Printf("[%v %v]\n", cmdName, cmdArgs)
+	err = c.Start() // returns immediately
+	if err != nil {
+		log.Printf("Command finished with error: %v", err)
+		return xsnet.CSEExecFail, err // !?
+	}
+	if err := c.Wait(); err != nil {
+		//fmt.Println("*** c.Wait() done ***")
+		if exiterr, ok := err.(*exec.ExitError); ok {
+			// The program has exited with an exit code != 0
+
+			// This works on both Unix and Windows. Although package
+			// syscall is generally platform dependent, WaitStatus is
+			// defined for both Unix and Windows and in both cases has
+			// an ExitStatus() method with the same signature.
+			if status, ok := exiterr.Sys().(syscall.WaitStatus); ok {
+				exitStatus = uint32(status.ExitStatus())
+				if len(stdErrBuffer.Bytes()) > 0 {
+					log.Print(stdErrBuffer)
+				}
+				log.Printf("Exit Status: %d", exitStatus)
+			}
+		}
+	}
+	//fmt.Println("*** server->client cp finished ***")
+	return
+}
+
+// Run a command (via default shell) as a specific user
+//
+// Uses ptys to support commands which expect a terminal.
+// nolint: gocyclo
+func runShellAs(who, hname, ttype, cmd string, interactive bool, conn *xsnet.Conn, chaffing bool) (exitStatus uint32, err error) {
+	var wg sync.WaitGroup
+	u, err := user.Lookup(who)
+	if err != nil {
+		exitStatus = 1
+		return
+	}
+	var uid, gid uint32
+	_, _ = fmt.Sscanf(u.Uid, "%d", &uid) // nolint: gosec
+	_, _ = fmt.Sscanf(u.Gid, "%d", &gid) // nolint: gosec
+	log.Println("uid:", uid, "gid:", gid)
+
+	// Need to clear server's env and set key vars of the
+	// target user. This isn't perfect (TERM doesn't seem to
+	// work 100%; ANSI/xterm colour isn't working even
+	// if we set "xterm" or "ansi" here; and line count
+	// reported by 'stty -a' defaults to 24 regardless
+	// of client shell window used to run client.
+	// Investigate -- rlm 2018-01-26)
+	os.Clearenv()
+	_ = os.Setenv("HOME", u.HomeDir) // nolint: gosec
+	_ = os.Setenv("TERM", ttype)     // nolint: gosec
+	_ = os.Setenv("XS_SESSION", "1")     // nolint: gosec
+
+	var c *exec.Cmd
+	if interactive {
+		if useSysLogin {
+			// Use the server's login binary (post-auth
+			// which is still done via our own bcrypt file)
+			// Things UNIX login does, like print the 'motd',
+			// and use the shell specified by /etc/passwd, will be done
+			// automagically, at the cost of another external tool
+			// dependency.
+			//
+			c = exec.Command(xs.GetTool("login"), "-f", "-p", who) // nolint: gosec
+		} else {
+			c = exec.Command(xs.GetTool("bash"), "-i", "-l") // nolint: gosec
+		}
+	} else {
+		c = exec.Command(xs.GetTool("bash"), "-c", cmd) // nolint: gosec
+	}
+	//If os.Clearenv() isn't called by server above these will be seen in the
+	//client's session env.
+	//c.Env = []string{"HOME=" + u.HomeDir, "SUDO_GID=", "SUDO_UID=", "SUDO_USER=", "SUDO_COMMAND=", "MAIL=", "LOGNAME="+who}
+	c.Dir = u.HomeDir
+	c.SysProcAttr = &syscall.SysProcAttr{}
+	if useSysLogin {
+		// If using server's login binary, drop to user creds
+		// is taken care of by it.
+		c.SysProcAttr.Credential = &syscall.Credential{}
+	} else {
+		c.SysProcAttr.Credential = &syscall.Credential{Uid: uid, Gid: gid}
+	}
+
+	// Start the command with a pty.
+	ptmx, err := pty.Start(c) // returns immediately with ptmx file
+	if err != nil {
+		log.Println(err)
+		return xsnet.CSEPtyExecFail, err
+	}
+	// Make sure to close the pty at the end.
+	// #gv:s/label=\"runShellAs\$1\"/label=\"deferPtmxClose\"/
+	defer func() {
+		//logger.LogDebug(fmt.Sprintf("[Exited process was %d]", c.Process.Pid))
+		_ = ptmx.Close()
+	}() // nolint: gosec
+
+	// get pty info for system accounting (who, lastlog)
+	pts, pe := ptsName(ptmx.Fd())
+	if pe != nil {
+		return xsnet.CSEPtyGetNameFail, err
+	}
+	utmpx := goutmp.Put_utmp(who, pts, hname)
+	defer func() { goutmp.Unput_utmp(utmpx) }()
+	goutmp.Put_lastlog_entry("xs", who, pts, hname)
+
+	log.Printf("[%s]\n", cmd)
+	if err != nil {
+		log.Printf("Command finished with error: %v", err)
+	} else {
+		// Watch for term resizes
+		// #gv:s/label=\"runShellAs\$2\"/label=\"termResizeWatcher\"/
+		go func() {
+			for sz := range conn.WinCh {
+				log.Printf("[Setting term size to: %v %v]\n", sz.Rows, sz.Cols)
+				pty.Setsize(ptmx, &pty.Winsize{Rows: sz.Rows, Cols: sz.Cols}) // nolint: gosec,errcheck
+			}
+			log.Println("*** WinCh goroutine done ***")
+		}()
+
+		// Copy stdin to the pty.. (bgnd goroutine)
+		// #gv:s/label=\"runShellAs\$3\"/label=\"stdinToPtyWorker\"/
+		go func() {
+			_, e := io.Copy(ptmx, conn)
+			if e != nil {
+				log.Println("** stdin->pty ended **:", e.Error())
+			} else {
+				log.Println("*** stdin->pty goroutine done ***")
+			}
+		}()
+
+		if chaffing {
+			conn.EnableChaff()
+		}
+		// #gv:s/label=\"runShellAs\$4\"/label=\"deferChaffShutdown\"/
+		defer func() {
+			conn.DisableChaff()
+			conn.ShutdownChaff()
+		}()
+
+		// ..and the pty to stdout.
+		// This may take some time exceeding that of the
+		// actual command's lifetime, so the c.Wait() below
+		// must synchronize with the completion of this goroutine
+		// to ensure all stdout data gets to the client before
+		// connection is closed.
+		wg.Add(1)
+		// #gv:s/label=\"runShellAs\$5\"/label=\"ptyToStdoutWorker\"/
+		go func() {
+			defer wg.Done()
+			_, e := io.Copy(conn, ptmx)
+			if e != nil {
+				log.Println("** pty->stdout ended **:", e.Error())
+			} else {
+				// The above io.Copy() will exit when the command attached
+				// to the pty exits
+				log.Println("*** pty->stdout goroutine done ***")
+			}
+		}()
+
+		if err := c.Wait(); err != nil {
+			//fmt.Println("*** c.Wait() done ***")
+			if exiterr, ok := err.(*exec.ExitError); ok {
+				// The program has exited with an exit code != 0
+
+				// This works on both Unix and Windows. Although package
+				// syscall is generally platform dependent, WaitStatus is
+				// defined for both Unix and Windows and in both cases has
+				// an ExitStatus() method with the same signature.
+				if status, ok := exiterr.Sys().(syscall.WaitStatus); ok {
+					exitStatus = uint32(status.ExitStatus())
+					log.Printf("Exit Status: %d", exitStatus)
+				}
+			}
+			conn.SetStatus(xsnet.CSOType(exitStatus))
+		} else {
+			logger.LogDebug("*** Main proc has exited. ***")
+			// Background jobs still may be running; close the
+			// pty anyway, so the client can return before
+			// wg.Wait() below completes (Issue #18)
+			if interactive {
+				_ = ptmx.Close()
+			}
+		}
+		wg.Wait() // Wait on pty->stdout completion to client
+	}
+	return
+}
+
+// GenAuthToken generates a pseudorandom auth token for a specific
+// user from a specific host to allow non-interactive logins.
+func GenAuthToken(who string, connhost string) string {
+	//tokenA, e := os.Hostname()
+	//if e != nil {
+	//	tokenA = "badhost"
+	//}
+	tokenA := connhost
+
+	tokenB := make([]byte, 64)
+	_, _ = rand.Read(tokenB) // nolint: gosec
+	return fmt.Sprintf("%s:%s", tokenA, hex.EncodeToString(tokenB))
+}
+
+var (
+	aKEXAlgs    allowedKEXAlgs
+	aCipherAlgs allowedCipherAlgs
+	aHMACAlgs   allowedHMACAlgs
+)
+
+type allowedKEXAlgs []string    // TODO
+type allowedCipherAlgs []string // TODO
+type allowedHMACAlgs []string   // TODO
+
+func (a allowedKEXAlgs) allowed(k xsnet.KEXAlg) bool {
+	for i := 0; i < len(a); i++ {
+		if a[i] == "KEX_all" || a[i] == k.String() {
+			return true
+		}
+	}
+	return false
+}
+
+func (a *allowedKEXAlgs) String() string {
+	return fmt.Sprintf("allowedKEXAlgs: %v", *a)
+}
+
+func (a *allowedKEXAlgs) Set(value string) error {
+	*a = append(*a, strings.TrimSpace(value))
+	return nil
+}
+
+func (a allowedCipherAlgs) allowed(c xsnet.CSCipherAlg) bool {
+	for i := 0; i < len(a); i++ {
+		if a[i] == "C_all" || a[i] == c.String() {
+			return true
+		}
+	}
+	return false
+}
+
+func (a *allowedCipherAlgs) String() string {
+	return fmt.Sprintf("allowedCipherAlgs: %v", *a)
+}
+
+func (a *allowedCipherAlgs) Set(value string) error {
+	*a = append(*a, strings.TrimSpace(value))
+	return nil
+}
+
+func (a allowedHMACAlgs) allowed(h xsnet.CSHmacAlg) bool {
+	for i := 0; i < len(a); i++ {
+		if a[i] == "H_all" || a[i] == h.String() {
+			return true
+		}
+	}
+	return false
+}
+
+func (a *allowedHMACAlgs) String() string {
+	return fmt.Sprintf("allowedHMACAlgs: %v", *a)
+}
+
+func (a *allowedHMACAlgs) Set(value string) error {
+	*a = append(*a, strings.TrimSpace(value))
+	return nil
+}
+
+// Main server that listens and spawns goroutines for each
+// connecting client to serve interactive or file copy sessions
+// and any requested tunnels.
+// Note that this server does not do UNIX forks of itself to give
+// each client its own separate manager process, so if the main
+// daemon dies, all clients will be rudely disconnected.
+// Consider this when planning to restart or upgrade in-place an installation.
+// TODO: reduce gocyclo
+func main() {
+	var vopt bool
+	var chaffEnabled bool
+	var chaffFreqMin uint
+	var chaffFreqMax uint
+	var chaffBytesMax uint
+	var dbg bool
+	var laddr string
+
+	var useSystemPasswd bool
+
+	flag.BoolVar(&vopt, "v", false, "show version")
+	flag.StringVar(&laddr, "l", ":2000", "interface[:port] to listen")
+	flag.StringVar(&kcpMode, "K", "unused", `set to one of ["KCP_NONE","KCP_AES", "KCP_BLOWFISH", "KCP_CAST5", "KCP_SM4", "KCP_SALSA20", "KCP_SIMPLEXOR", "KCP_TEA", "KCP_3DES", "KCP_TWOFISH", "KCP_XTEA"] to use KCP (github.com/xtaci/kcp-go) reliable UDP instead of TCP`)
+	flag.BoolVar(&useSysLogin, "L", false, "use system login")
+	flag.BoolVar(&chaffEnabled, "e", true, "enable chaff pkts")
+	flag.UintVar(&chaffFreqMin, "f", 100, "chaff pkt freq min (msecs)")
+	flag.UintVar(&chaffFreqMax, "F", 5000, "chaff pkt freq max (msecs)")
+	flag.UintVar(&chaffBytesMax, "B", 64, "chaff pkt size max (bytes)")
+	flag.BoolVar(&useSystemPasswd, "s", true, "use system shadow passwds")
+	flag.BoolVar(&dbg, "d", false, "debug logging")
+
+	flag.Var(&aKEXAlgs, "aK", `List of allowed KEX algs (eg. 'KEXAlgA KEXAlgB ... KEXAlgN') (default allow all)`)
+	flag.Var(&aCipherAlgs, "aC", `List of allowed ciphers (eg. 'CipherAlgA CipherAlgB ... CipherAlgN') (default allow all)`)
+	flag.Var(&aHMACAlgs, "aH", `List of allowed HMACs (eg. 'HMACAlgA HMACAlgB ... HMACAlgN') (default allow all)`)
+
+	flag.Parse()
+
+	if vopt {
+		fmt.Printf("version %s (%s)\n", version, gitCommit)
+		os.Exit(0)
+	}
+
+	{
+		me, e := user.Current()
+		if e != nil || me.Uid != "0" {
+			log.Fatal("Must run as root.")
+		}
+	}
+
+	// Enforce some sane min/max vals on chaff flags
+	if chaffFreqMin < 2 {
+		chaffFreqMin = 2
+	}
+	if chaffFreqMax == 0 {
+		chaffFreqMax = chaffFreqMin + 1
+	}
+	if chaffBytesMax == 0 || chaffBytesMax > 4096 {
+		chaffBytesMax = 64
+	}
+
+	Log, _ = logger.New(logger.LOG_DAEMON|logger.LOG_DEBUG|logger.LOG_NOTICE|logger.LOG_ERR, "xsd") // nolint: gosec
+	xsnet.Init(dbg, "xsd", logger.LOG_DAEMON|logger.LOG_DEBUG|logger.LOG_NOTICE|logger.LOG_ERR)
+	if dbg {
+		log.SetOutput(Log)
+	} else {
+		log.SetOutput(ioutil.Discard)
+	}
+
+	// Set up allowed algs, if specified (default allow all)
+	if len(aKEXAlgs) == 0 {
+		aKEXAlgs = []string{"KEX_all"}
+	}
+	logger.LogNotice(fmt.Sprintf("Allowed KEXAlgs: %v\n", aKEXAlgs)) // nolint: gosec,errcheck
+
+	if len(aCipherAlgs) == 0 {
+		aCipherAlgs = []string{"C_all"}
+	}
+	logger.LogNotice(fmt.Sprintf("Allowed CipherAlgs: %v\n", aCipherAlgs)) // nolint: gosec,errcheck
+
+	if len(aHMACAlgs) == 0 {
+		aHMACAlgs = []string{"H_all"}
+	}
+	logger.LogNotice(fmt.Sprintf("Allowed HMACAlgs: %v\n", aHMACAlgs)) // nolint: gosec,errcheck
+
+	// Set up handler for daemon signalling
+	exitCh := make(chan os.Signal, 1)
+	signal.Notify(exitCh, os.Signal(syscall.SIGTERM), os.Signal(syscall.SIGINT), os.Signal(syscall.SIGHUP), os.Signal(syscall.SIGUSR1), os.Signal(syscall.SIGUSR2))
+	go func() {
+		for {
+			sig := <-exitCh
+			switch sig.String() {
+			case "terminated":
+				logger.LogNotice(fmt.Sprintf("[Got signal: %s]", sig)) // nolint: gosec,errcheck
+				signal.Reset()
+				syscall.Kill(0, syscall.SIGTERM) // nolint: gosec,errcheck
+			case "interrupt":
+				logger.LogNotice(fmt.Sprintf("[Got signal: %s]", sig)) // nolint: gosec,errcheck
+				signal.Reset()
+				syscall.Kill(0, syscall.SIGINT) // nolint: gosec,errcheck
+			case "hangup":
+				logger.LogNotice(fmt.Sprintf("[Got signal: %s - nop]", sig)) // nolint:gosec,errcheck
+			default:
+				logger.LogNotice(fmt.Sprintf("[Got signal: %s - ignored]", sig)) // nolint: gosec,errcheck
+			}
+		}
+	}()
+
+	proto := "tcp"
+	if kcpMode != "unused" {
+		proto = "kcp"
+	}
+	l, err := xsnet.Listen(proto, laddr, kcpMode)
+	if err != nil {
+		log.Fatal(err)
+	}
+	defer l.Close() // nolint: errcheck
+
+	log.Println("Serving on", laddr)
+	for {
+		// Wait for a connection.
+		// Then check if client-proposed algs are allowed
+		conn, err := l.Accept()
+		if err != nil {
+			log.Printf("Accept() got error(%v), hanging up.\n", err)
+		} else if !aKEXAlgs.allowed(conn.KEX()) {
+			log.Printf("Accept() rejected for banned KEX alg %d, hanging up.\n", conn.KEX())
+			conn.SetStatus(xsnet.CSEKEXAlgDenied)
+			conn.Close()
+		} else if !aCipherAlgs.allowed(conn.CAlg()) {
+			log.Printf("Accept() rejected for banned Cipher alg %d, hanging up.\n", conn.CAlg())
+			conn.SetStatus(xsnet.CSECipherAlgDenied)
+			conn.Close()
+		} else if !aHMACAlgs.allowed(conn.HAlg()) {
+			log.Printf("Accept() rejected for banned HMAC alg %d, hanging up.\n", conn.HAlg())
+			conn.SetStatus(xsnet.CSEHMACAlgDenied)
+			conn.Close()
+		} else {
+			log.Println("Accepted client")
+
+			// Set up chaffing to client
+			// Will only start when runShellAs() is called
+			// after stdin/stdout are hooked up
+			conn.SetupChaff(chaffFreqMin, chaffFreqMax, chaffBytesMax) // configure server->client chaffing
+
+			// Handle the connection in a new goroutine.
+			// The loop then returns to accepting, so that
+			// multiple connections may be served concurrently.
+			go func(hc *xsnet.Conn) (e error) {
+				defer hc.Close() // nolint: errcheck
+
+				// Start login timeout here and disconnect if user/pass phase stalls
+				loginTimeout := time.AfterFunc(30*time.Second, func() {
+					logger.LogNotice(fmt.Sprintln("Login timed out")) // nolint: errcheck,gosec
+					hc.Write([]byte{0})                               // nolint: gosec,errcheck
+					hc.Close()
+				})
+
+				//We use io.ReadFull() here to guarantee we consume
+				//just the data we want for the xs.Session, and no more.
+				//Otherwise data will be sitting in the channel that isn't
+				//passed down to the command handlers.
+				var rec xs.Session
+				var len1, len2, len3, len4, len5, len6 uint32
+
+				n, err := fmt.Fscanf(hc, "%d %d %d %d %d %d\n", &len1, &len2, &len3, &len4, &len5, &len6)
+				log.Printf("xs.Session read:%d %d %d %d %d %d\n", len1, len2, len3, len4, len5, len6)
+
+				if err != nil || n < 6 {
+					log.Println("[Bad xs.Session fmt]")
+					return err
+				}
+
+				tmp := make([]byte, len1)
+				_, err = io.ReadFull(hc, tmp)
+				if err != nil {
+					log.Println("[Bad xs.Session.Op]")
+					return err
+				}
+				rec.SetOp(tmp)
+
+				tmp = make([]byte, len2)
+				_, err = io.ReadFull(hc, tmp)
+				if err != nil {
+					log.Println("[Bad xs.Session.Who]")
+					return err
+				}
+				rec.SetWho(tmp)
+
+				tmp = make([]byte, len3)
+				_, err = io.ReadFull(hc, tmp)
+				if err != nil {
+					log.Println("[Bad xs.Session.ConnHost]")
+					return err
+				}
+				rec.SetConnHost(tmp)
+
+				tmp = make([]byte, len4)
+				_, err = io.ReadFull(hc, tmp)
+				if err != nil {
+					log.Println("[Bad xs.Session.TermType]")
+					return err
+				}
+				rec.SetTermType(tmp)
+
+				tmp = make([]byte, len5)
+				_, err = io.ReadFull(hc, tmp)
+				if err != nil {
+					log.Println("[Bad xs.Session.Cmd]")
+					return err
+				}
+				rec.SetCmd(tmp)
+
+				tmp = make([]byte, len6)
+				_, err = io.ReadFull(hc, tmp)
+				if err != nil {
+					log.Println("[Bad xs.Session.AuthCookie]")
+					return err
+				}
+				rec.SetAuthCookie(tmp)
+
+				log.Printf("[xs.Session: op:%c who:%s connhost:%s cmd:%s auth:****]\n",
+					rec.Op()[0], string(rec.Who()), string(rec.ConnHost()), string(rec.Cmd()))
+
+				var valid bool
+				var allowedCmds string // Currently unused
+				if xs.AuthUserByToken(xs.NewAuthCtx(), string(rec.Who()), string(rec.ConnHost()), string(rec.AuthCookie(true))) {
+					valid = true
+				} else {
+					if useSystemPasswd {
+						//var passErr error
+						valid, _ /*passErr*/ = xs.VerifyPass(xs.NewAuthCtx(), string(rec.Who()), string(rec.AuthCookie(true)))
+					} else {
+						valid, allowedCmds = xs.AuthUserByPasswd(xs.NewAuthCtx(), string(rec.Who()), string(rec.AuthCookie(true)), "/etc/xs.passwd")
+					}
+				}
+
+				_ = loginTimeout.Stop()
+				// Security scrub
+				rec.ClearAuthCookie()
+
+				// Tell client if auth was valid
+				if valid {
+					hc.Write([]byte{1}) // nolint: gosec,errcheck
+				} else {
+					logger.LogNotice(fmt.Sprintln("Invalid user", string(rec.Who()))) // nolint: errcheck,gosec
+					hc.Write([]byte{0})                                               // nolint: gosec,errcheck
+					return
+				}
+
+				log.Printf("[allowedCmds:%s]\n", allowedCmds)
+
+				if rec.Op()[0] == 'A' {
+					// Generate automated login token
+					addr := hc.RemoteAddr()
+					hname := goutmp.GetHost(addr.String())
+					logger.LogNotice(fmt.Sprintf("[Generating autologin token for [%s@%s]]\n", rec.Who(), hname)) // nolint: gosec,errcheck
+					token := GenAuthToken(string(rec.Who()), string(rec.ConnHost()))
+					tokenCmd := fmt.Sprintf("echo \"%s\" | tee -a ~/.xs_id", token)
+					cmdStatus, runErr := runShellAs(string(rec.Who()), hname, string(rec.TermType()), tokenCmd, false, hc, chaffEnabled)
+					// Returned hopefully via an EOF or exit/logout;
+					// Clear current op so user can enter next, or EOF
+					rec.SetOp([]byte{0})
+					if runErr != nil {
+						logger.LogErr(fmt.Sprintf("[Error generating autologin token for %s@%s]\n", rec.Who(), hname)) // nolint: gosec,errcheck
+					} else {
+						log.Printf("[Autologin token generation completed for %s@%s, status %d]\n", rec.Who(), hname, cmdStatus)
+						hc.SetStatus(xsnet.CSOType(cmdStatus))
+					}
+				} else if rec.Op()[0] == 'c' {
+					// Non-interactive command
+					addr := hc.RemoteAddr()
+					hname := goutmp.GetHost(addr.String())
+					logger.LogNotice(fmt.Sprintf("[Running command for [%s@%s]]\n", rec.Who(), hname)) // nolint: gosec,errcheck
+					cmdStatus, runErr := runShellAs(string(rec.Who()), hname, string(rec.TermType()), string(rec.Cmd()), false, hc, chaffEnabled)
+					// Returned hopefully via an EOF or exit/logout;
+					// Clear current op so user can enter next, or EOF
+					rec.SetOp([]byte{0})
+					if runErr != nil {
+						logger.LogErr(fmt.Sprintf("[Error spawning cmd for %s@%s]\n", rec.Who(), hname)) // nolint: gosec,errcheck
+					} else {
+						logger.LogNotice(fmt.Sprintf("[Command completed for %s@%s, status %d]\n", rec.Who(), hname, cmdStatus)) // nolint: gosec,errcheck
+						hc.SetStatus(xsnet.CSOType(cmdStatus))
+					}
+				} else if rec.Op()[0] == 's' {
+					// Interactive session
+					addr := hc.RemoteAddr()
+					hname := goutmp.GetHost(addr.String())
+					logger.LogNotice(fmt.Sprintf("[Running shell for [%s@%s]]\n", rec.Who(), hname)) // nolint: gosec,errcheck
+
+					cmdStatus, runErr := runShellAs(string(rec.Who()), hname, string(rec.TermType()), string(rec.Cmd()), true, hc, chaffEnabled)
+					// Returned hopefully via an EOF or exit/logout;
+					// Clear current op so user can enter next, or EOF
+					rec.SetOp([]byte{0})
+					if runErr != nil {
+						Log.Err(fmt.Sprintf("[Error spawning shell for %s@%s]\n", rec.Who(), hname)) // nolint: gosec,errcheck
+					} else {
+						logger.LogNotice(fmt.Sprintf("[Shell completed for %s@%s, status %d]\n", rec.Who(), hname, cmdStatus)) // nolint: gosec,errcheck
+						hc.SetStatus(xsnet.CSOType(cmdStatus))
+					}
+				} else if rec.Op()[0] == 'D' {
+					// File copy (destination) operation - client copy to server
+					log.Printf("[Client->Server copy]\n")
+					addr := hc.RemoteAddr()
+					hname := goutmp.GetHost(addr.String())
+					logger.LogNotice(fmt.Sprintf("[Running copy for [%s@%s]]\n", rec.Who(), hname)) // nolint: gosec,errcheck
+					cmdStatus, runErr := runClientToServerCopyAs(string(rec.Who()), string(rec.TermType()), hc, string(rec.Cmd()), chaffEnabled)
+					// Returned hopefully via an EOF or exit/logout;
+					// Clear current op so user can enter next, or EOF
+					rec.SetOp([]byte{0})
+					if runErr != nil {
+						logger.LogErr(fmt.Sprintf("[Error running cp for %s@%s]\n", rec.Who(), hname)) // nolint: gosec,errcheck
+					} else {
+						logger.LogNotice(fmt.Sprintf("[Command completed for %s@%s, status %d]\n", rec.Who(), hname, cmdStatus)) // nolint: gosec,errcheck
+					}
+					// TODO: Test this with huge files.. see Bug #22 - do we need to
+					//   sync w/sender (client) that we've gotten all data?
+					hc.SetStatus(xsnet.CSOType(cmdStatus))
+
+					// Send CSOExitStatus *before* client closes channel
+					s := make([]byte, 4)
+					binary.BigEndian.PutUint32(s, cmdStatus)
+					log.Printf("** cp writing closeStat %d at Close()\n", cmdStatus)
+					hc.WritePacket(s, xsnet.CSOExitStatus) // nolint: gosec,errcheck
+				} else if rec.Op()[0] == 'S' {
+					// File copy (src) operation - server copy to client
+					log.Printf("[Server->Client copy]\n")
+					addr := hc.RemoteAddr()
+					hname := goutmp.GetHost(addr.String())
+					logger.LogNotice(fmt.Sprintf("[Running copy for [%s@%s]]\n", rec.Who(), hname)) // nolint: gosec,errcheck
+					cmdStatus, runErr := runServerToClientCopyAs(string(rec.Who()), string(rec.TermType()), hc, string(rec.Cmd()), chaffEnabled)
+					if runErr != nil {
+						logger.LogErr(fmt.Sprintf("[Error spawning cp for %s@%s]\n", rec.Who(), hname)) // nolint: gosec,errcheck
+					} else {
+						// Returned hopefully via an EOF or exit/logout;
+						logger.LogNotice(fmt.Sprintf("[Command completed for %s@%s, status %d]\n", rec.Who(), hname, cmdStatus)) // nolint: gosec,errcheck
+					}
+					// HACK: Bug #22: (xc) Need to wait for rcvr to get final data
+					// TODO: Await specific msg from client to inform they have gotten all data from the tarpipe
+					time.Sleep(time.Duration(900 * time.Millisecond)) // Let rcvr set this on setup?
+
+					// Clear current op so user can enter next, or EOF
+					rec.SetOp([]byte{0})
+					hc.SetStatus(xsnet.CSOType(cmdStatus))
+					//fmt.Println("Waiting for EOF from other end.")
+					//_, _ = hc.Read(nil /*ackByte*/)
+					//fmt.Println("Got remote end ack.")
+				} else {
+					logger.LogErr(fmt.Sprintln("[Bad xs.Session]")) // nolint: gosec,errcheck
+				}
+				return
+			}(&conn) // nolint: errcheck
+		} // Accept() success
+	} //endfor
+	//logger.LogNotice(fmt.Sprintln("[Exiting]")) // nolint: gosec,errcheck
+}

xsnet/Makefile

@@ -0,0 +1,17 @@
+.PHONY: info clean lib
+
+all: lib
+
+clean:
+	go clean .
+
+lib: info
+	go install .
+
+ifneq ($(MSYSTEM),)
+info:
+	@echo "Building for Windows (MSYS)"
+else
+info:
+	@echo "Building for Linux"
+endif

xsnet/chan.go

@@ -1,6 +1,6 @@
-package hkexsh
+package xsnet
 
-// Copyright (c) 2017-2018 Russell Magee
+// Copyright (c) 2017-2020 Russell Magee
 // Licensed under the terms of the MIT license (see LICENSE.mit in this
 // distribution)
 //
@@ -19,34 +19,47 @@ import (
 	"fmt"
 	"hash"
 	"log"
-	"math/big"
 
+	"blitter.com/go/cryptmt"
+	"github.com/aead/chacha20/chacha"
 	"golang.org/x/crypto/blowfish"
 	"golang.org/x/crypto/twofish"
+
 	// hash algos must be manually imported thusly:
 	// (Would be nice if the golang pkg docs were more clear
 	// on this...)
 	_ "crypto/sha256"
+	_ "crypto/sha512"
 )
 
-// Available ciphers for hkex.Conn
+// Expand keymat, if necessary, to a minimum of 2x(blocksize).
-const (
+// Keymat is used for initial key and the IV, hence the 2x.
-	CAlgAES256     = iota
+// This is occasionally necessary for smaller modes of KEX algorithms
-	CAlgTwofish128 // golang.org/x/crypto/twofish
+// (eg., KEX_HERRADURA256); perhaps an indication these should be
-	CAlgBlowfish64 // golang.org/x/crypto/blowfish
+// avoided in favour of larger modes.
-	CAlgNoneDisallowed
+//
-)
+// This is used for block ciphers; stream ciphers should do their
-
+// own key expansion.
-// Available HMACs for hkex.Conn (TODO: not currently used)
+func expandKeyMat(keymat []byte, blocksize int) []byte {
-const (
+	if len(keymat) < 2*blocksize {
-	HmacSHA256 = iota
+		halg := crypto.SHA256
-	HmacNoneDisallowed
+		mc := halg.New()
-)
+		if !halg.Available() {
+			log.Fatal("hash not available!")
+		}
+		_, _ = mc.Write(keymat)
+		var xpand []byte
+		xpand = mc.Sum(xpand)
+		keymat = append(keymat, xpand...)
+		log.Println("[NOTE: keymat short - applying key expansion using SHA256]")
+	}
+	return keymat
+}
 
 /* Support functionality to set up encryption after a channel has
-been negotiated via hkexnet.go
+been negotiated via xsnet.go
 */
-func (hc Conn) getStream(keymat *big.Int) (rc cipher.Stream, mc hash.Hash, err error) {
+func (hc *Conn) getStream(keymat []byte) (rc cipher.Stream, mc hash.Hash, err error) {
 	var key []byte
 	var block cipher.Block
 	var iv []byte
@@ -57,23 +70,24 @@ func (hc Conn) getStream(keymat *big.Int) (rc cipher.Stream, mc hash.Hash, err e
 	// is >= 2*cipher.BlockSize (enough for both key and iv)
 	switch copts {
 	case CAlgAES256:
-		key = keymat.Bytes()[0:aes.BlockSize]
+		keymat = expandKeyMat(keymat, aes.BlockSize)
+		key = keymat[0:aes.BlockSize]
 		block, err = aes.NewCipher(key)
 		ivlen = aes.BlockSize
-		iv = keymat.Bytes()[aes.BlockSize : aes.BlockSize+ivlen]
+		iv = keymat[aes.BlockSize : aes.BlockSize+ivlen]
 		rc = cipher.NewOFB(block, iv)
 		log.Printf("[cipher AES_256 (%d)]\n", copts)
-		break
 	case CAlgTwofish128:
-		key = keymat.Bytes()[0:twofish.BlockSize]
+		keymat = expandKeyMat(keymat, twofish.BlockSize)
+		key = keymat[0:twofish.BlockSize]
 		block, err = twofish.NewCipher(key)
 		ivlen = twofish.BlockSize
-		iv = keymat.Bytes()[twofish.BlockSize : twofish.BlockSize+ivlen]
+		iv = keymat[twofish.BlockSize : twofish.BlockSize+ivlen]
 		rc = cipher.NewOFB(block, iv)
 		log.Printf("[cipher TWOFISH_128 (%d)]\n", copts)
-		break
 	case CAlgBlowfish64:
-		key = keymat.Bytes()[0:blowfish.BlockSize]
+		keymat = expandKeyMat(keymat, blowfish.BlockSize)
+		key = keymat[0:blowfish.BlockSize]
 		block, err = blowfish.NewCipher(key)
 		ivlen = blowfish.BlockSize
 		// N.b. Bounds enforcement of differing cipher algorithms
@@ -85,10 +99,24 @@ func (hc Conn) getStream(keymat *big.Int) (rc cipher.Stream, mc hash.Hash, err e
 		//
 		// I assume the other two check bounds and only
 		// copy what's needed whereas blowfish does no such check.
-		iv = keymat.Bytes()[blowfish.BlockSize : blowfish.BlockSize+ivlen]
+		iv = keymat[blowfish.BlockSize : blowfish.BlockSize+ivlen]
 		rc = cipher.NewOFB(block, iv)
 		log.Printf("[cipher BLOWFISH_64 (%d)]\n", copts)
-		break
+	case CAlgCryptMT1:
+		rc = cryptmt.New(nil, nil, keymat)
+		log.Printf("[cipher CRYPTMT1 (%d)]\n", copts)
+	case CAlgChaCha20_12:
+		keymat = expandKeyMat(keymat, chacha.KeySize)
+		key = keymat[0:chacha.KeySize]
+		ivlen = chacha.INonceSize
+		iv = keymat[chacha.KeySize : chacha.KeySize+ivlen]
+		rc, err = chacha.NewCipher(iv, key, chacha.INonceSize)
+		if err != nil {
+			log.Printf("[ChaCha20 config error]\n")
+			fmt.Printf("[ChaCha20 config error]\n")
+		}
+		// TODO: SetCounter() to something derived from key or nonce or extra keymat?
+		log.Printf("[cipher CHACHA20_12 (%d)]\n", copts)
 	default:
 		log.Printf("[invalid cipher (%d)]\n", copts)
 		fmt.Printf("DOOFUS SET A VALID CIPHER ALG (%d)\n", copts)
@@ -105,7 +133,13 @@ func (hc Conn) getStream(keymat *big.Int) (rc cipher.Stream, mc hash.Hash, err e
 		if !halg.Available() {
 			log.Fatal("hash not available!")
 		}
-		break
+	case HmacSHA512:
+		log.Printf("[hash HmacSHA512 (%d)]\n", hopts)
+		halg := crypto.SHA512
+		mc = halg.New()
+		if !halg.Available() {
+			log.Fatal("hash not available!")
+		}
 	default:
 		log.Printf("[invalid hmac (%d)]\n", hopts)
 		fmt.Printf("DOOFUS SET A VALID HMAC ALG (%d)\n", hopts)

xsnet/consts.go

@@ -0,0 +1,124 @@
+// consts.go - consts for xsnet
+
+// Copyright (c) 2017-2020 Russell Magee
+// Licensed under the terms of the MIT license (see LICENSE.mit in this
+// distribution)
+//
+// golang implementation by Russ Magee (rmagee_at_gmail.com)
+package xsnet
+
+// KEX algorithm values
+//
+// Specified (in string form) as the extensions parameter
+// to xsnet.Dial()
+// Alg is sent in a uint8 so there are up to 256 possible
+const (
+	KEX_HERRADURA256 = iota // this MUST be first for default if omitted in ctor
+	KEX_HERRADURA512
+	KEX_HERRADURA1024
+	KEX_HERRADURA2048
+	KEX_resvd4
+	KEX_resvd5
+	KEX_resvd6
+	KEX_resvd7
+	KEX_KYBER512
+	KEX_KYBER768
+	KEX_KYBER1024
+	KEX_resvd11
+	KEX_NEWHOPE
+	KEX_NEWHOPE_SIMPLE // 'NewHopeLP-Simple' - https://eprint.iacr.org/2016/1157
+	KEX_resvd14
+	KEX_resvd15
+	KEX_FRODOKEM_1344AES
+	KEX_FRODOKEM_1344SHAKE
+	KEX_FRODOKEM_976AES
+	KEX_FRODOKEM_976SHAKE
+	KEX_invalid = 255
+)
+
+// Sent from client to server in order to specify which
+// algo shall be used (see xsnet.KEX_HERRADURA256, ...)
+type KEXAlg uint8
+
+// Extended exit status codes - indicate comm/pty issues
+// rather than remote end normal UNIX exit codes
+const (
+	CSENone            = 1024 + iota
+	CSETruncCSO        // No CSOExitStatus in payload
+	CSEStillOpen       // Channel closed unexpectedly
+	CSEExecFail        // cmd.Start() (exec) failed
+	CSEPtyExecFail     // pty.Start() (exec w/pty) failed
+	CSEPtyGetNameFail  // failed to obtain pty name
+	CSEKEXAlgDenied    // server rejected proposed KEX alg
+	CSECipherAlgDenied // server rejected proposed Cipher alg
+	CSEHMACAlgDenied   // server rejected proposed HMAC alg
+)
+
+// Extended (>255 UNIX exit status) codes
+// This indicate channel-related or internal errors
+type CSExtendedCode uint32
+
+// Channel Status/Op bytes - packet types
+const (
+	// Main connection/session control
+	CSONone        = iota // No error, normal packet
+	CSOHmacInvalid        // HMAC mismatch detected on remote end
+	CSOTermSize           // set term size (rows:cols)
+	CSOExitStatus         // Remote cmd exit status
+	CSOChaff              // Dummy packet, do not pass beyond decryption
+
+	// Client side errors
+	CSOLoginTimeout
+
+	// Tunnel setup/control/status
+	CSOTunSetup     // client -> server tunnel setup request (dstport)
+	CSOTunSetupAck  // server -> client tunnel setup ack
+	CSOTunRefused   // server -> client: tunnel rport connection refused
+	CSOTunData      // packet contains tunnel data [rport:data]
+	CSOTunKeepAlive // client tunnel heartbeat
+	CSOTunDisconn   // server -> client: tunnel rport disconnected
+	CSOTunHangup    // client -> server: tunnel lport hung up
+)
+
+// TunEndpoint.tunCtl control values - used to control workers for client
+// or server tunnels depending on the code
+const (
+	TunCtl_Client_Listen = 'a'
+	// [CSOTunAccept]
+	// status: server has ack'd tun setup request
+	// action: client should accept (after re-listening, if required) on lport
+
+	TunCtl_Server_Dial = 'd' // server has dialled OK, client side can accept() conns
+	// [CSOTunAccept]
+	// status: client wants to open tunnel to rport
+	// action:server side should dial() rport on client's behalf
+)
+
+// Channel status Op byte type (see CSONone, ... and CSENone, ...)
+type CSOType uint32
+
+//TODO: this should be small (max unfragmented packet size?)
+const MAX_PAYLOAD_LEN = 2*1024*1024*1024 - 1
+
+// Session symmetric crypto algs
+const (
+	CAlgAES256     = iota
+	CAlgTwofish128 // golang.org/x/crypto/twofish
+	CAlgBlowfish64 // golang.org/x/crypto/blowfish
+	CAlgCryptMT1   //cryptmt using mtwist64
+	CAlgChaCha20_12
+	CAlgNoneDisallowed
+)
+
+// Available ciphers for hkex.Conn
+type CSCipherAlg uint32
+
+// Session packet auth HMAC algs
+const (
+	HmacSHA256 = iota
+	HmacSHA512
+	HmacNoneDisallowed
+)
+
+// Available HMACs for hkex.Conn
+type CSHmacAlg uint32

xsnet/kcp.go

@@ -0,0 +1,129 @@
+package xsnet
+
+import (
+	"crypto/sha1"
+	"errors"
+	"fmt"
+	"net"
+
+	"blitter.com/go/xs/logger"
+	kcp "github.com/xtaci/kcp-go"
+	"golang.org/x/crypto/pbkdf2"
+)
+
+const (
+	KCP_NONE = iota
+	KCP_AES
+	KCP_BLOWFISH
+	KCP_CAST5
+	KCP_SM4
+	KCP_SALSA20
+	KCP_SIMPLEXOR
+	KCP_TEA
+	KCP_3DES
+	KCP_TWOFISH
+	KCP_XTEA
+)
+
+// for github.com/xtaci/kcp-go BlockCrypt alg selection
+type KCPAlg uint8
+
+var (
+	kcpKeyBytes  []byte = []byte("SET THIS") // symmetric crypto key for KCP (github.com/xtaci/kcp-go) if used
+	kcpSaltBytes []byte = []byte("ALSO SET THIS")
+)
+
+func getKCPalgnum(extensions []string) (k KCPAlg) {
+	k = KCP_AES // default
+	var s string
+	for _, s = range extensions {
+		switch s {
+		case "KCP_NONE":
+			k = KCP_NONE
+			break //golint:ignore SA4011 out of for
+		case "KCP_AES":
+			k = KCP_AES
+			break //out of for
+		case "KCP_BLOWFISH":
+			k = KCP_BLOWFISH
+			break //out of for
+		case "KCP_CAST5":
+			k = KCP_CAST5
+			break //out of for
+		case "KCP_SM4":
+			k = KCP_SM4
+			break //out of for
+		case "KCP_SALSA20":
+			k = KCP_SALSA20
+			break //out of for
+		case "KCP_SIMPLEXOR":
+			k = KCP_SIMPLEXOR
+			break //out of for
+		case "KCP_TEA":
+			k = KCP_TEA
+			break //out of for
+		case "KCP_3DES":
+			k = KCP_3DES
+			break //out of for
+		case "KCP_TWOFISH":
+			k = KCP_TWOFISH
+			break //out of for
+		case "KCP_XTEA":
+			k = KCP_XTEA
+			break //out of for
+		}
+	}
+	logger.LogDebug(fmt.Sprintf("[KCP BlockCrypt '%s' activated]", s))
+	return
+}
+
+func SetKCPKeyAndSalt(key []byte, salt []byte) {
+	kcpKeyBytes = key
+	kcpSaltBytes = salt
+}
+
+func _newKCPBlockCrypt(key []byte, extensions []string) (b kcp.BlockCrypt, e error) {
+	switch getKCPalgnum(extensions) {
+	case KCP_NONE:
+		return kcp.NewNoneBlockCrypt(key)
+	case KCP_AES:
+		return kcp.NewAESBlockCrypt(key)
+	case KCP_BLOWFISH:
+		return kcp.NewBlowfishBlockCrypt(key)
+	case KCP_CAST5:
+		return kcp.NewCast5BlockCrypt(key)
+	case KCP_SM4:
+		return kcp.NewSM4BlockCrypt(key)
+	case KCP_SALSA20:
+		return kcp.NewSalsa20BlockCrypt(key)
+	case KCP_SIMPLEXOR:
+		return kcp.NewSimpleXORBlockCrypt(key)
+	case KCP_TEA:
+		return kcp.NewTEABlockCrypt(key)
+	case KCP_3DES:
+		return kcp.NewTripleDESBlockCrypt(key)
+	case KCP_TWOFISH:
+		return kcp.NewTwofishBlockCrypt(key)
+	case KCP_XTEA:
+		return kcp.NewXTEABlockCrypt(key)
+	}
+	return nil, errors.New("Invalid KCP BlockCrypto specified")
+}
+
+func kcpDial(ipport string, extensions []string) (c net.Conn, err error) {
+	kcpKey := pbkdf2.Key(kcpKeyBytes, kcpSaltBytes, 1024, 32, sha1.New)
+	block, be := _newKCPBlockCrypt([]byte(kcpKey), extensions)
+	_ = be
+	return kcp.DialWithOptions(ipport, block, 10, 3)
+}
+
+func kcpListen(ipport string, extensions []string) (l net.Listener, err error) {
+	kcpKey := pbkdf2.Key(kcpKeyBytes, kcpSaltBytes, 1024, 32, sha1.New)
+	block, be := _newKCPBlockCrypt([]byte(kcpKey), extensions)
+	_ = be
+	return kcp.ListenWithOptions(ipport, block, 10, 3)
+}
+
+func (hl *HKExListener) AcceptKCP() (c net.Conn, e error) {
+	return hl.l.(*kcp.Listener).AcceptKCP()
+}

xsnet/tun.go

@@ -0,0 +1,418 @@
+// hkextun.go - Tunnel setup using an established xsnet.Conn
+
+// Copyright (c) 2017-2020 Russell Magee
+// Licensed under the terms of the MIT license (see LICENSE.mit in this
+// distribution)
+//
+// golang implementation by Russ Magee (rmagee_at_gmail.com)
+
+package xsnet
+
+import (
+	"bytes"
+	"encoding/binary"
+	"fmt"
+	"io"
+	"net"
+	"strings"
+	"sync"
+	"time"
+
+	"blitter.com/go/xs/logger"
+)
+
+type (
+	// Tunnels
+	// --
+	// 1. client is given (lport, remhost, rport) by local user
+	// 2. client sends [CSOTunReq:rport] to server
+	// client=> [CSOTunReq:rport] =>remhost
+	//
+	// remhost starts worker to receive/send data using rport
+	// remhost replies to client with rport to acknowledge tun is ready
+	// client<= [CSOTunAck:rport] <=remhost
+	//   ... or if rhost rport refuses connection, sends
+	//   [CSOTunRefused:rport]
+	//
+	// client starts worker to receive/send data using lport
+	// ... client disconnects: sends remhost [CSOTunClose:rport]
+	// ... or server disconnects: sends client [CSOTunClose:lport]
+	//     server at any time sends [CSOTunRefused:rport] if daemon died
+	// --
+
+	// TunEndpoint [securePort:peer:dataPort]
+	TunEndpoint struct {
+		Rport     uint16    // Names are from client's perspective
+		Lport     uint16    // ... ie., RPort is on server, LPort is on client
+		Peer      string    //net.Addr
+		Died      bool      // set by client upon receipt of a CSOTunDisconn
+		KeepAlive uint32    // must be reset by client to keep server dial() alive
+		Ctl       chan rune //See TunCtl_* consts
+		Data      chan []byte
+	}
+)
+
+func (hc *Conn) CollapseAllTunnels(client bool) {
+	for k, t := range *hc.tuns {
+		var tunDst bytes.Buffer
+		binary.Write(&tunDst, binary.BigEndian, t.Lport)
+		binary.Write(&tunDst, binary.BigEndian, t.Rport)
+		if client {
+			hc.WritePacket(tunDst.Bytes(), CSOTunHangup)
+		} else {
+			hc.WritePacket(tunDst.Bytes(), CSOTunDisconn)
+		}
+		delete(*hc.tuns, k)
+	}
+}
+
+func (hc *Conn) InitTunEndpoint(lp uint16, p string /* net.Addr */, rp uint16) {
+	hc.Lock()
+	defer hc.Unlock()
+	if (*hc.tuns) == nil {
+		(*hc.tuns) = make(map[uint16]*TunEndpoint)
+	}
+	if (*hc.tuns)[rp] == nil {
+		var addrs []net.Addr
+		if p == "" {
+			addrs, _ = net.InterfaceAddrs()
+			p = addrs[0].String()
+		}
+		(*hc.tuns)[rp] = &TunEndpoint{ /*Status: CSOTunSetup,*/ Peer: p,
+			Lport: lp, Rport: rp, Data: make(chan []byte, 1),
+			Ctl: make(chan rune, 1)}
+		logger.LogDebug(fmt.Sprintf("InitTunEndpoint [%d:%s:%d]", lp, p, rp))
+	} else {
+		logger.LogDebug(fmt.Sprintf("InitTunEndpoint [reusing] %v", (*hc.tuns)[rp]))
+		if (*hc.tuns)[rp].Data == nil {
+			// When re-using a tunnel it will have its
+			// data channel removed on closure. Re-create it
+			(*hc.tuns)[rp].Data = make(chan []byte, 1)
+		}
+		(*hc.tuns)[rp].KeepAlive = 0
+		(*hc.tuns)[rp].Died = false
+	}
+	return
+}
+
+func (hc *Conn) StartClientTunnel(lport, rport uint16) {
+	hc.InitTunEndpoint(lport, "", rport)
+
+	go func() {
+		var wg sync.WaitGroup
+
+		for cmd := range (*hc.tuns)[rport].Ctl {
+			if cmd == 'a' {
+				l, e := net.Listen("tcp4", fmt.Sprintf(":%d", lport))
+				if e != nil {
+					logger.LogDebug(fmt.Sprintf("[ClientTun] Could not get lport %d! (%s)", lport, e))
+				} else {
+					logger.LogDebug(fmt.Sprintf("[ClientTun] Listening for client tunnel port %d", lport))
+
+					for {
+						c, e := l.Accept() // blocks until new conn
+						// If tunnel is being re-used, re-init it
+						if (*hc.tuns)[rport] == nil {
+							hc.InitTunEndpoint(lport, "", rport)
+						}
+						// ask server to dial() its side, rport
+						var tunDst bytes.Buffer
+						binary.Write(&tunDst, binary.BigEndian, lport)
+						binary.Write(&tunDst, binary.BigEndian, rport)
+						hc.WritePacket(tunDst.Bytes(), CSOTunSetup)
+
+						if e != nil {
+							logger.LogDebug(fmt.Sprintf("[ClientTun] Accept() got error(%v), hanging up.", e))
+						} else {
+							logger.LogDebug(fmt.Sprintf("[ClientTun] Accepted tunnel client %v", (*hc.tuns)[rport]))
+
+							// outside client -> tunnel lport
+							wg.Add(1)
+							go func() {
+								defer func() {
+									if c.Close() != nil {
+										logger.LogDebug("[ClientTun] worker A: conn c already closed")
+									} else {
+										logger.LogDebug("[ClientTun] worker A: closed conn c")
+									}
+									wg.Done()
+								}()
+
+								logger.LogDebug("[ClientTun] worker A: starting")
+
+								var tunDst bytes.Buffer
+								binary.Write(&tunDst, binary.BigEndian, lport)
+								binary.Write(&tunDst, binary.BigEndian, rport)
+								for {
+									rBuf := make([]byte, 1024)
+									//Read data from c, encrypt/write via hc to client(lport)
+									c.SetReadDeadline(time.Now().Add(200 * time.Millisecond))
+									n, e := c.Read(rBuf)
+									if e != nil {
+										if e == io.EOF {
+											logger.LogDebug(fmt.Sprintf("[ClientTun] worker A: lport Disconnected: shutting down tunnel %v", (*hc.tuns)[rport]))
+											// if Died was already set, server-side already is gone.
+											if hc.TunIsAlive(rport) {
+												hc.WritePacket(tunDst.Bytes(), CSOTunHangup)
+											}
+											hc.ShutdownTun(rport) // FIXME: race-C
+											break
+										} else if strings.Contains(e.Error(), "i/o timeout") {
+											if !hc.TunIsAlive(rport) {
+												logger.LogDebug(fmt.Sprintf("[ClientTun] worker A: timeout: Server side died, hanging up %v", (*hc.tuns)[rport]))
+												hc.ShutdownTun(rport)
+												break
+											}
+										} else {
+											logger.LogDebug(fmt.Sprintf("[ClientTun] worker A: Read error from lport of tun %v\n%s", (*hc.tuns)[rport], e))
+											if hc.TunIsAlive(rport) {
+												hc.WritePacket(tunDst.Bytes(), CSOTunHangup)
+											}
+											hc.ShutdownTun(rport)
+											break
+										}
+									}
+									if n > 0 {
+										rBuf = append(tunDst.Bytes(), rBuf[:n]...)
+										_, de := hc.WritePacket(rBuf[:n+4], CSOTunData)
+										if de != nil {
+											logger.LogDebug(fmt.Sprintf("[ClientTun] worker A: Error writing to tunnel %v, %s]\n", (*hc.tuns)[rport], de))
+											break
+										}
+									}
+								}
+								logger.LogDebug("[ClientTun] worker A: exiting")
+							}()
+
+							// tunnel lport -> outside client (c)
+							wg.Add(1)
+							go func() {
+								defer func() {
+									if c.Close() != nil {
+										logger.LogDebug("[ClientTun] worker B: conn c already closed")
+									} else {
+										logger.LogDebug("[ClientTun] worker B: closed conn c")
+									}
+									wg.Done()
+								}()
+
+								logger.LogDebug("[ClientTun] worker B: starting")
+
+								for {
+									bytes, ok := <-(*hc.tuns)[rport].Data // FIXME: race-C w/ShutdownTun calls
+									if ok {
+										c.SetWriteDeadline(time.Now().Add(200 * time.Millisecond))
+										_, e := c.Write(bytes)
+										if e != nil {
+											logger.LogDebug(fmt.Sprintf("[ClientTun] worker B: lport conn closed"))
+											break
+										}
+									} else {
+										logger.LogDebug(fmt.Sprintf("[ClientTun] worker B: Channel was closed?"))
+										break
+									}
+								}
+								logger.LogDebug("[ClientTun] worker B: exiting")
+							}()
+
+						} // end Accept() worker block
+						wg.Wait()
+
+						// When both workers have exited due to a disconnect or other
+						// condition, it's safe to remove the tunnel descriptor.
+						logger.LogDebug("[ClientTun] workers exited")
+						hc.ShutdownTun(rport)
+					} // end for-accept
+				} // end Listen() block
+			}
+		} // end t.Ctl for
+	}()
+}
+
+func (hc *Conn) AgeTunnel(endp uint16) uint32 {
+	hc.Lock()
+	defer hc.Unlock()
+	(*hc.tuns)[endp].KeepAlive += 1
+	return (*hc.tuns)[endp].KeepAlive
+}
+
+func (hc *Conn) ResetTunnelAge(endp uint16) {
+	hc.Lock()
+	defer hc.Unlock()
+	(*hc.tuns)[endp].KeepAlive = 0
+}
+
+func (hc *Conn) TunIsNil(endp uint16) bool {
+	hc.Lock()
+	defer hc.Unlock()
+	return (*hc.tuns)[endp] == nil
+}
+
+func (hc *Conn) TunIsAlive(endp uint16) bool {
+	hc.Lock()
+	defer hc.Unlock()
+	return !(*hc.tuns)[endp].Died
+}
+
+func (hc *Conn) MarkTunDead(endp uint16) {
+	hc.Lock()
+	defer hc.Unlock()
+	(*hc.tuns)[endp].Died = true
+}
+
+func (hc *Conn) ShutdownTun(endp uint16) {
+	hc.Lock()
+	defer hc.Unlock()
+	if (*hc.tuns)[endp] != nil {
+		(*hc.tuns)[endp].Died = true
+		if (*hc.tuns)[endp].Data != nil {
+			close((*hc.tuns)[endp].Data)
+			(*hc.tuns)[endp].Data = nil
+		}
+	}
+	delete((*hc.tuns), endp)
+}
+
+func (hc *Conn) StartServerTunnel(lport, rport uint16) {
+	hc.InitTunEndpoint(lport, "", rport)
+	var err error
+
+	go func() {
+		var wg sync.WaitGroup
+
+		//
+		// worker to age server tunnel and kill it if keepalives
+		// stop from client
+		//
+		wg.Add(1)
+		go func() {
+			defer wg.Done()
+			for {
+				time.Sleep(100 * time.Millisecond)
+				if hc.TunIsNil(rport) {
+					logger.LogDebug("[ServerTun] worker A: Client endpoint removed.")
+					break
+				}
+				age := hc.AgeTunnel(rport)
+				if age > 25 {
+					hc.MarkTunDead(rport)
+					logger.LogDebug("[ServerTun] worker A: Client died, hanging up.")
+					break
+				}
+			}
+		}()
+
+		for cmd := range (*hc.tuns)[rport].Ctl {
+			var c net.Conn
+			logger.LogDebug(fmt.Sprintf("[ServerTun] got Ctl '%c'.", cmd))
+			if cmd == 'd' {
+				// if re-using tunnel, re-init it
+				if hc.TunIsNil(rport) {
+					hc.InitTunEndpoint(lport, "", rport)
+				}
+				logger.LogDebug("[ServerTun] dialling...")
+				c, err = net.Dial("tcp4", fmt.Sprintf(":%d", rport))
+				if err != nil {
+					logger.LogDebug(fmt.Sprintf("[ServerTun] Dial() error for tun %v: %s", (*hc.tuns)[rport], err))
+					var resp bytes.Buffer
+					binary.Write(&resp, binary.BigEndian /*lport*/, uint16(0))
+					binary.Write(&resp, binary.BigEndian, rport)
+					hc.WritePacket(resp.Bytes(), CSOTunRefused)
+				} else {
+					logger.LogDebug(fmt.Sprintf("[ServerTun] Tunnel Opened - %v", (*hc.tuns)[rport]))
+					var resp bytes.Buffer
+					binary.Write(&resp, binary.BigEndian, lport)
+					binary.Write(&resp, binary.BigEndian, rport)
+					logger.LogDebug(fmt.Sprintf("[ServerTun] Writing CSOTunSetupAck %v", (*hc.tuns)[rport]))
+					hc.WritePacket(resp.Bytes(), CSOTunSetupAck)
+
+					//
+					// worker to read data from the rport (to encrypt & send to client)
+					//
+					wg.Add(1)
+					go func() {
+						defer func() {
+							logger.LogDebug("[ServerTun] worker A: deferred hangup")
+							if c.Close() != nil {
+								logger.LogDebug("[ServerTun] workerA: conn c already closed")
+							}
+							wg.Done()
+						}()
+
+						logger.LogDebug("[ServerTun] worker A: starting")
+
+						var tunDst bytes.Buffer
+						binary.Write(&tunDst, binary.BigEndian, (*hc.tuns)[rport].Lport)
+						binary.Write(&tunDst, binary.BigEndian, (*hc.tuns)[rport].Rport)
+						for {
+							rBuf := make([]byte, 1024)
+							// Read data from c, encrypt/write via hc to client(lport)
+							c.SetReadDeadline(time.Now().Add(200 * time.Millisecond))
+							n, e := c.Read(rBuf)
+							if e != nil {
+								if e == io.EOF {
+									logger.LogDebug(fmt.Sprintf("[ServerTun] worker A: rport Disconnected: shutting down tunnel %v", (*hc.tuns)[rport]))
+									if hc.TunIsAlive(rport) {
+										hc.WritePacket(tunDst.Bytes(), CSOTunDisconn)
+									}
+									hc.ShutdownTun(rport) // FIXME: race-A
+									break
+								} else if strings.Contains(e.Error(), "i/o timeout") {
+									if !hc.TunIsAlive(rport) {
+										logger.LogDebug(fmt.Sprintf("[ServerTun] worker A: timeout: Server side died, hanging up %v", (*hc.tuns)[rport]))
+										hc.ShutdownTun(rport) // FIXME: race-B
+										break
+									}
+								} else {
+									logger.LogDebug(fmt.Sprintf("[ServerTun] worker A: Read error from rport of tun %v: %s", (*hc.tuns)[rport], e))
+									if hc.TunIsAlive(rport) {
+										hc.WritePacket(tunDst.Bytes(), CSOTunDisconn)
+									}
+									hc.ShutdownTun(rport) // FIXME: race-C
+									break
+								}
+							}
+							if n > 0 {
+								rBuf = append(tunDst.Bytes(), rBuf[:n]...)
+								hc.WritePacket(rBuf[:n+4], CSOTunData)
+							}
+						}
+						logger.LogDebug("[ServerTun] worker A: exiting")
+					}()
+
+					// worker to read data from client (already decrypted) & fwd to rport
+					wg.Add(1)
+					go func() {
+						defer func() {
+							logger.LogDebug("[ServerTun] worker B: deferred hangup")
+							if c.Close() != nil {
+								logger.LogDebug("[ServerTun] worker B: conn c already closed")
+							}
+							wg.Done()
+						}()
+
+						logger.LogDebug("[ServerTun] worker B: starting")
+						for {
+							rData, ok := <-(*hc.tuns)[rport].Data // FIXME: race-A, race-B, race-C (w/ShutdownTun() calls)
+							if ok {
+								c.SetWriteDeadline(time.Now().Add(200 * time.Millisecond))
+								_, e := c.Write(rData)
+								if e != nil {
+									logger.LogDebug(fmt.Sprintf("[ServerTun] worker B: ERROR writing to rport conn"))
+									break
+								}
+							} else {
+								logger.LogDebug(fmt.Sprintf("[ServerTun] worker B: Channel was closed?"))
+								break
+							}
+						}
+						logger.LogDebug("[ServerTun] worker B: exiting")
+					}()
+					wg.Wait()
+				} // end if Dialled successfully
+				delete((*hc.tuns), rport)
+			}
+		} // t.Ctl read loop
+		logger.LogDebug("[ServerTun] Tunnel exiting t.Ctl read loop - channel closed??")
+	}()
+}

xspasswd/Makefile

@@ -0,0 +1,16 @@
+.PHONY: clean all vis lint
+
+EXTPKGS = bytes,errors,flag,fmt,internal,io,log,net,os,path,runtime,time,strings,sync,syscall,binary,encoding
+EXE = $(notdir $(shell pwd))
+
+all:
+	go build $(BUILDOPTS) .
+
+clean:
+	$(RM) $(EXE) $(EXE).exe
+
+vis:
+	go-callvis -format png -file xspasswd-vis -ignore $(EXTPKGS) -group pkg,type .
+
+lint:
+	-golangci-lint run

xspasswd/xspasswd.go

@@ -1,7 +1,7 @@
 // Util to generate/store passwords for users in a file akin to /etc/passwd
 // suitable for the demo hkexsh server, using bcrypt.
 //
-// Copyright (c) 2017-2018 Russell Magee
+// Copyright (c) 2017-2020 Russell Magee
 // Licensed under the terms of the MIT license (see LICENSE.mit in this
 // distribution)
 //
@@ -16,37 +16,50 @@ import (
 	"io/ioutil"
 	"log"
 	"os"
-	"os/user"
 
+	xs "blitter.com/go/xs"
 	"github.com/jameskeane/bcrypt"
-	hkexsh "blitter.com/go/hkexsh"
 )
 
+var (
+	version   string
+	gitCommit string
+)
+
+// nolint: gocyclo
 func main() {
+	var vopt bool
 	var pfName string
 	var newpw string
 	var confirmpw string
 	var userName string
 
+	flag.BoolVar(&vopt, "v", false, "show version")
 	flag.StringVar(&userName, "u", "", "username")
-	flag.StringVar(&pfName, "f", "/etc/hkexsh.passwd", "passwd file")
+	flag.StringVar(&pfName, "f", "/etc/xs.passwd", "passwd file")
 	flag.Parse()
 
+	if vopt {
+		fmt.Printf("version %s (%s)\n", version, gitCommit)
+		os.Exit(0)
+	}
+
 	var uname string
 	if len(userName) == 0 {
 		log.Println("specify username with -u")
 		os.Exit(1)
 	}
 
-	u, err := user.Lookup(userName)
+	//u, err := user.Lookup(userName)
-	if err != nil {
+	//if err != nil {
-		log.Printf("Invalid user %s\n", userName)
+	//	log.Printf("Invalid user %s\n", userName)
-		log.Fatal(err)
+	//	log.Fatal(err)
-	}
+	//}
-	uname = u.Username
+	//uname = u.Username
+	uname = userName
 
 	fmt.Printf("New Password:")
-	ab, err := hkexsh.ReadPassword(int(os.Stdin.Fd()))
+	ab, err := xs.ReadPassword(os.Stdin.Fd())
 	fmt.Printf("\r\n")
 	if err != nil {
 		log.Fatal(err)
@@ -55,7 +68,7 @@ func main() {
 	newpw = string(ab)
 
 	fmt.Printf("Confirm:")
-	ab, err = hkexsh.ReadPassword(int(os.Stdin.Fd()))
+	ab, err = xs.ReadPassword(os.Stdin.Fd())
 	fmt.Printf("\r\n")
 	if err != nil {
 		log.Fatal(err)
@@ -84,7 +97,7 @@ func main() {
 	}
 	//fmt.Println("Salt:", salt, "Hash:", hash)
 
-	b, err := ioutil.ReadFile(pfName)
+	b, err := ioutil.ReadFile(pfName) // nolint: gosec
 	if err != nil {
 		log.Fatal(err)
 	}
@@ -92,15 +105,18 @@ func main() {
 
 	r.Comma = ':'
 	r.Comment = '#'
-	r.FieldsPerRecord = 4 // username:salt:authCookie:disallowedCmdList (a,b,...)
+	r.FieldsPerRecord = 3 // username:salt:authCookie [TODO:disallowedCmdList (a,b,...)]
 
 	records, err := r.ReadAll()
 	if err != nil {
 		log.Fatal(err)
 	}
-	for i, _ := range records {
+
+	recFound := false
+	for i := range records {
 		//fmt.Println(records[i])
 		if records[i][0] == uname {
+			recFound = true
 			records[i][1] = salt
 			records[i][2] = hash
 		}
@@ -109,16 +125,26 @@ func main() {
 		//	records[i][0] = "#" + records[i][0]
 		//}
 	}
+	if !recFound {
+		newRec := []string{uname, salt, hash}
+		records = append(records, newRec)
+	}
 
-	outFile, err := ioutil.TempFile("", "hkexsh-passwd")
+	outFile, err := ioutil.TempFile("", "xs-passwd")
 	if err != nil {
 		log.Fatal(err)
 	}
 	w := csv.NewWriter(outFile)
 	w.Comma = ':'
 	//w.FieldsPerRecord = 4 // username:salt:authCookie:disallowedCmdList (a,b,...)
-	w.Write([]string{"#username", "salt", "authCookie", "disallowedCmdList"})
+	err = w.Write([]string{"#username", "salt", "authCookie" /*, "disallowedCmdList"*/})
-	w.WriteAll(records)
+	if err != nil {
+		log.Fatal(err)
+	}
+	err = w.WriteAll(records)
+	if err != nil {
+		log.Fatal(err)
+	}
 	if err = w.Error(); err != nil {
 		log.Fatal(err)
 	}