mirror of
https://gogs.blitter.com/RLabs/xs
synced 2024-08-14 10:26:42 +00:00
80 lines
3.5 KiB
Markdown
80 lines
3.5 KiB
Markdown
HKExSh
|
|
--
|
|
|
|
'hkexsh' (HerraduraKEx shell) is a golang implementation of a simple
|
|
remote shell client and server, similar in role to ssh, offering
|
|
encrypted interactive and non-interactive sessions. The client and server
|
|
programs (hkexsh and hkexshd) 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
|
|
first released at
|
|
[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
|
|
net.Listen() with hkex.Listen(), to obtain connections (hkex.Conn) conforming
|
|
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
|
|
(server/hkexshd and client/hkexsh) negotiate session settings (cipher/hmac
|
|
algorithms, interactive/non-interactive, etc.) to be used for further
|
|
communication.
|
|
|
|
Packets are subject to random padding, and (optionally) the client and server
|
|
channels can both send _chaff_ packets at random defineable intervals to help
|
|
thwart analysis of session activity (especially for interactive shell sessions).
|
|
|
|
NOTE: Due to the experimental nature of the HerraduraKEx algorithm used to
|
|
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
|
|
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
|
|
using its own user/password file distinct from the system /etc/passwd, which
|
|
is used by the hkexshd server to authenticate clients.
|
|
|
|
Dependencies:
|
|
--
|
|
* Recent version of go (tested with go-1.9)
|
|
* [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://blitter.com/gogs/Russtopia/goutmp) // wtmp/lastlog C bindings
|
|
|
|
Get source code
|
|
--
|
|
* $ go get -u blitter.com/go/hkexsh
|
|
* $ cd $GOPATH/src/blitter.com/go/hkexsh
|
|
* $ go build ./... # install all dependent go pkgs
|
|
|
|
To build
|
|
--
|
|
* $ cd $GOPATH/src/blitter.com/go/hkexsh
|
|
* $ make clean all
|
|
|
|
To set accounts & passwords:
|
|
--
|
|
* $ echo "joebloggs:*:*:*" >hkexsh.passwd
|
|
* $ sudo mv hkexsh.passwd /etc
|
|
* $ sudo hkexpasswd/hkexpasswd -u joebloggs
|
|
* $ <enter a password, enter again to confirm>
|
|
|
|
Running Clent and Server. In separate shells:
|
|
--
|
|
* [A]$ sudo hkexshd/hkexshd & # add -d for debugging
|
|
* [B]$ hkexsh/hkexsh -u joebloggs # add -d for debugging
|
|
|
|
NOTE if running client (hkexsh) 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.
|
|
|