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Merge branch 'conn-keepalive' of RLabs/xs into master

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Merge of branch conn-keepalive
This commit is contained in:
Russtopia 2023-11-06 23:48:51 -08:00 committed by Gogs
commit 36799ba9e7
5 changed files with 170 additions and 47 deletions
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2
Makefile
View file

@ -1,4 +1,4 @@
VERSION := 0.9.5.5
VERSION := 0.9.5.6-rc
.PHONY: lint vis clean common client server passwd\
subpkgs install uninstall reinstall scc

10
xs/xs.go
View file

@ -1005,7 +1005,7 @@ func main() { //nolint: funlen, gocyclo
loginTimeout := time.AfterFunc(30*time.Second, func() { //nolint:gomnd
restoreTermState(oldState)
fmt.Printf(" .. [login timeout]\n")
exitWithStatus(xsnet.CSOLoginTimeout)
exitWithStatus(xsnet.CSELoginTimeout)
})
if authCookie == "" {
@ -1059,13 +1059,16 @@ func main() { //nolint: funlen, gocyclo
fmt.Fprintln(os.Stderr, rejectUserMsg())
rec.SetStatus(GeneralProtocolErr)
} else {
// === Set up connection keepalive to server
conn.StartupKeepAlive() // goroutine, returns immediately
defer conn.ShutdownKeepAlive()
// === Set up chaffing to server
conn.SetupChaff(chaffFreqMin, chaffFreqMax, chaffBytesMax) // enable client->server chaffing
if chaffEnabled {
// #gv:s/label=\"main\$2\"/label=\"deferCloseChaff\"/
// TODO:.gv:main:2:deferCloseChaff
conn.EnableChaff() // goroutine, returns immediately
defer conn.DisableChaff()
conn.StartupChaff() // goroutine, returns immediately
defer conn.ShutdownChaff()
}
@ -1148,6 +1151,5 @@ func exitWithStatus(status int) {
log.Fatal("could not write memory profile: ", err) //nolint:gocritic
}
}
os.Exit(status)
}

96
xsd/xsd.go
View file

@ -17,11 +17,14 @@ import (
"fmt"
"io"
"log"
"net/http"
"os"
"os/exec"
"os/signal"
"os/user"
"path"
"runtime"
"runtime/pprof"
"strings"
"sync"
"syscall"
@ -44,6 +47,9 @@ var (
// Log - syslog output (with no -d)
Log *logger.Writer
cpuprofile string
memprofile string
)
const (
@ -115,10 +121,13 @@ func runClientToServerCopyAs(who, ttype string, conn *xsnet.Conn, fpath string,
c.Stdout = os.Stdout
c.Stderr = os.Stderr
// === Set up connection keepalive to client
conn.StartupKeepAlive() // goroutine, returns immediately
defer conn.ShutdownKeepAlive()
if chaffing {
conn.EnableChaff()
conn.StartupChaff()
}
defer conn.DisableChaff()
defer conn.ShutdownChaff()
// Start the command (no pty)
@ -212,11 +221,14 @@ func runServerToClientCopyAs(who, ttype string, conn *xsnet.Conn, srcPath string
c.Stderr = stdErrBuffer
//c.Stderr = nil
// === Set up connection keepalive to client
conn.StartupKeepAlive() // goroutine, returns immediately
defer conn.ShutdownKeepAlive()
if chaffing {
conn.EnableChaff()
conn.StartupChaff()
}
//defer conn.Close()
defer conn.DisableChaff()
defer conn.ShutdownChaff()
// Start the command (no pty)
@ -274,21 +286,28 @@ func runShellAs(who, hname, ttype, cmd string, interactive bool, //nolint:funlen
if interactive {
if useSysLogin {
// Use the server's login binary (post-auth, which
// is still done via our own bcrypt file)
//
// Note login will drop privs to the intended user for us
// Use the server's login binary (post-auth)
//
// 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.
//
// One drawback of using 'login' is that the remote side
// cannot give us back the shell's exit code, since it
// exits back to 'login', which usually returns its own
// 0 status back to us.
//
// Note login will drop privs to the intended user for us.
//
c = exec.Command(xs.GetTool("login"), "-f", "-p", who) //nolint:gosec
} else {
// Using our separate login via local passwd file
// Run shell directly (which allows nonzero exit codes back to
// the local system upon shell exit, whereas 'login' does not.)
//
// Note we must drop privs ourselves for the user shell
// Note we must drop privs ourselves for the user shell since
// we aren't using 'login' on the remote end which would do it
// for us.
//
c = exec.Command(xs.GetTool("bash"), "-i", "-l") //nolint:gosec
c.SysProcAttr = &syscall.SysProcAttr{}
@ -327,6 +346,9 @@ func runShellAs(who, hname, ttype, cmd string, interactive bool, //nolint:funlen
defer func() { goutmp.Unput_utmp(utmpx) }()
goutmp.Put_lastlog_entry("xs", who, pts, hname)
conn.Pproc = c.Process.Pid
//fmt.Printf("[process %d started]\n", c.Process.Pid)
log.Printf("[%s]\n", cmd)
if err != nil {
log.Printf("Command finished with error: %v", err)
@ -352,12 +374,15 @@ func runShellAs(who, hname, ttype, cmd string, interactive bool, //nolint:funlen
}
}()
// === Set up connection keepalive to client
conn.StartupKeepAlive() // goroutine, returns immediately
defer conn.ShutdownKeepAlive()
if chaffing {
conn.EnableChaff()
conn.StartupChaff()
}
// #gv:s/label=\"runShellAs\$4\"/label=\"deferChaffShutdown\"/
defer func() {
conn.DisableChaff()
conn.ShutdownChaff()
}()
@ -397,7 +422,7 @@ func runShellAs(who, hname, ttype, cmd string, interactive bool, //nolint:funlen
}
conn.SetStatus(xsnet.CSOType(exitStatus))
} else {
logger.LogDebug("*** Main proc has exited. ***") //nolint:errcheck
logger.LogDebug(fmt.Sprintf("*** Main proc has exited (%d) ***", c.ProcessState.ExitCode())) //nolint:errcheck
// Background jobs still may be running; close the
// pty anyway, so the client can return before
// wg.Wait() below completes (Issue #18)
@ -545,6 +570,9 @@ func main() { //nolint:funlen,gocyclo
H_SHA256
H_SHA512`)
flag.StringVar(&cpuprofile, "cpuprofile", "", "write cpu profile to <`file`>")
flag.StringVar(&memprofile, "memprofile", "", "write memory profile to <`file`>")
flag.Parse()
if vopt {
@ -559,6 +587,24 @@ func main() { //nolint:funlen,gocyclo
}
}
// === Profiling instrumentation
if cpuprofile != "" {
f, err := os.Create(cpuprofile)
if err != nil {
log.Fatal("could not create CPU profile: ", err)
}
defer f.Close()
fmt.Println("StartCPUProfile()")
if err := pprof.StartCPUProfile(f); err != nil {
log.Fatal("could not start CPU profile: ", err) //nolint:gocritic
} else {
defer pprof.StopCPUProfile()
}
go func() { http.ListenAndServe("localhost:6060", nil) }() //nolint:errcheck,gosec
}
// Enforce some sane min/max vals on chaff flags
if chaffFreqMin < 2 { //nolint:gomnd
chaffFreqMin = 2
@ -611,6 +657,9 @@ func main() { //nolint:funlen,gocyclo
syscall.Kill(0, syscall.SIGINT) //nolint:errcheck
case "hangup":
logger.LogNotice(fmt.Sprintf("[Got signal: %s - nop]", sig)) //nolint:errcheck
if cpuprofile != "" || memprofile != "" {
dumpProf()
}
default:
logger.LogNotice(fmt.Sprintf("[Got signal: %s - ignored]", sig)) //nolint:errcheck
}
@ -632,6 +681,7 @@ func main() { //nolint:funlen,gocyclo
// Wait for a connection.
// Then check if client-proposed algs are allowed
conn, err := l.Accept()
//logger.LogDebug(fmt.Sprintf("l.Accept()\n"))
if err != nil {
log.Printf("Accept() got error(%v), hanging up.\n", err)
} else {
@ -864,3 +914,23 @@ func main() { //nolint:funlen,gocyclo
} //endfor
//logger.LogNotice(fmt.Sprintln("[Exiting]")) //nolint:errcheck
}
func dumpProf() {
if cpuprofile != "" {
pprof.StopCPUProfile()
}
if memprofile != "" {
f, err := os.Create(memprofile)
if err != nil {
log.Fatal("could not create memory profile: ", err)
}
defer f.Close()
runtime.GC() // get up-to-date statistics
if err := pprof.WriteHeapProfile(f); err != nil {
log.Fatal("could not write memory profile: ", err) //nolint:gocritic
}
}
//os.Exit(status)
}

8
xsnet/consts.go
View file

@ -52,6 +52,8 @@ const (
CSEKEXAlgDenied // server rejected proposed KEX alg
CSECipherAlgDenied // server rejected proposed Cipher alg
CSEHMACAlgDenied // server rejected proposed HMAC alg
CSEConnDead // connection keepalives expired
CSELoginTimeout
)
// Extended (>255 UNIX exit status) codes
@ -67,9 +69,6 @@ const (
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
@ -78,6 +77,7 @@ const (
CSOTunKeepAlive // client tunnel heartbeat
CSOTunDisconn // server -> client: tunnel rport disconnected
CSOTunHangup // client -> server: tunnel lport hung up
CSOKeepAlive // bidir keepalive packet to monitor main connection
)
// TunEndpoint.tunCtl control values - used to control workers for client
@ -97,7 +97,7 @@ const (
// Channel status Op byte type (see CSONone, ... and CSENone, ...)
type CSOType uint32
//TODO: this should be small (max unfragmented packet size?)
// TODO: this should be small (max unfragmented packet size?)
const MAX_PAYLOAD_LEN = 2*1024*1024*1024 - 1
// Session symmetric crypto algs

101
xsnet/net.go
View file

@ -39,6 +39,7 @@ import (
"net"
"strings"
"sync"
"syscall"
"time"
hkex "blitter.com/go/herradurakex"
@ -64,7 +65,6 @@ type (
// see: https://en.wikipedia.org/wiki/chaff_(countermeasure)
ChaffConfig struct {
shutdown bool //set to inform chaffHelper to shut down
enabled bool
msecsMin uint //msecs min interval
msecsMax uint //msecs max interval
szMax uint // max size in bytes
@ -87,8 +87,10 @@ type (
Rows uint16
Cols uint16
chaff ChaffConfig
tuns *map[uint16](*TunEndpoint)
keepalive uint // if this reaches zero, conn is considered dead
Pproc int // proc ID of command run on this conn
chaff ChaffConfig
tuns *map[uint16](*TunEndpoint)
closeStat *CSOType // close status (CSOExitStatus)
r cipher.Stream //read cipherStream
@ -971,7 +973,7 @@ func Dial(protocol string, ipport string, extensions ...string) (hc Conn, err er
// Close a hkex.Conn
func (hc *Conn) Close() (err error) {
hc.DisableChaff()
hc.ShutdownChaff()
s := make([]byte, 4)
binary.BigEndian.PutUint32(s, uint32(*hc.closeStat))
log.Printf("** Writing closeStat %d at Close()\n", *hc.closeStat)
@ -1196,7 +1198,7 @@ func (hl *HKExListener) Accept() (hc Conn, err error) {
// packet processing.
//
// See go doc io.Reader
func (hc Conn) Read(b []byte) (n int, err error) {
func (hc *Conn) Read(b []byte) (n int, err error) {
for {
if hc.dBuf.Len() > 0 {
break
@ -1214,7 +1216,8 @@ func (hc Conn) Read(b []byte) (n int, err error) {
return 0, io.EOF
}
if strings.HasSuffix(err.Error(), "use of closed network connection") {
logger.LogDebug(fmt.Sprintln("[Client hung up]"))
logger.LogDebug(fmt.Sprintln("[Client hung up(1)]"))
//!rlm hc.SetStatus(CSENone) //FIXME: re-examine this (exit 9 w/o it - 2023-11-05)
return 0, io.EOF
}
etxt := fmt.Sprintf("** Failed read:%s (%s) **", "ctrlStatOp", err)
@ -1237,7 +1240,7 @@ func (hc Conn) Read(b []byte) (n int, err error) {
return 0, io.EOF
}
if strings.HasSuffix(err.Error(), "use of closed network connection") {
logger.LogDebug(fmt.Sprintln("[Client hung up]"))
logger.LogDebug(fmt.Sprintln("[Client hung up(2)]"))
return 0, io.EOF
}
etxt := fmt.Sprintf("** Failed read:%s (%s) **", "HMAC", err)
@ -1253,7 +1256,7 @@ func (hc Conn) Read(b []byte) (n int, err error) {
return 0, io.EOF
}
if strings.HasSuffix(err.Error(), "use of closed network connection") {
logger.LogDebug(fmt.Sprintln("[Client hung up]"))
logger.LogDebug(fmt.Sprintln("[Client hung up(3)]"))
return 0, io.EOF
}
etxt := fmt.Sprintf("** Failed read:%s (%s) **", "payloadLen", err)
@ -1276,7 +1279,7 @@ func (hc Conn) Read(b []byte) (n int, err error) {
return 0, io.EOF
}
if strings.HasSuffix(err.Error(), "use of closed network connection") {
logger.LogDebug(fmt.Sprintln("[Client hung up]"))
logger.LogDebug(fmt.Sprintln("[Client hung up(4)]"))
return 0, io.EOF
}
etxt := fmt.Sprintf("** Failed read:%s (%s) **", "payloadBytes", err)
@ -1337,6 +1340,11 @@ func (hc Conn) Read(b []byte) (n int, err error) {
case CSOChaff:
// Throw away pkt if it's chaff (ie., caller to Read() won't see this data)
log.Printf("[Chaff pkt, discarded (len %d)]\n", decryptN)
case CSOKeepAlive:
//logger.LogDebug(fmt.Sprintf("[got keepAlive pkt, discarded (len %d)]\n", decryptN))
// payload of keepalive (2 bytes) is not currently used (0x55aa fixed)
_ = binary.BigEndian.Uint16(payloadBytes[0:2])
hc.ResetKeepAlive()
case CSOTermSize:
fmt.Sscanf(string(payloadBytes), "%d %d", &hc.Rows, &hc.Cols)
log.Printf("[TermSize pkt: rows %v cols %v]\n", hc.Rows, hc.Cols)
@ -1568,18 +1576,12 @@ func (hc *Conn) WritePacket(b []byte, ctrlStatOp byte) (n int, err error) {
return retN, err
}
func (hc *Conn) EnableChaff() {
func (hc *Conn) StartupChaff() {
hc.chaff.shutdown = false
hc.chaff.enabled = true
log.Println("Chaffing ENABLED")
hc.chaffHelper()
}
func (hc *Conn) DisableChaff() {
hc.chaff.enabled = false
log.Println("Chaffing DISABLED")
}
func (hc *Conn) ShutdownChaff() {
hc.chaff.shutdown = true
log.Println("Chaffing SHUTDOWN")
@ -1594,9 +1596,10 @@ func (hc *Conn) SetupChaff(msecsMin uint, msecsMax uint, szMax uint) {
// Helper routine to spawn a chaffing goroutine for each Conn
func (hc *Conn) chaffHelper() {
go func() {
var nextDuration int
for {
var nextDuration int
if hc.chaff.enabled {
//logger.LogDebug(fmt.Sprintf("[chaffHelper Loop]\n"))
if !hc.chaff.shutdown {
var bufTmp []byte
bufTmp = make([]byte, rand.Intn(int(hc.chaff.szMax)))
min := int(hc.chaff.msecsMin)
@ -1604,17 +1607,65 @@ func (hc *Conn) chaffHelper() {
_, _ = rand.Read(bufTmp)
_, err := hc.WritePacket(bufTmp, CSOChaff)
if err != nil {
log.Println("[ *** error - chaffHelper quitting *** ]")
hc.chaff.enabled = false
log.Println("[ *** error - chaffHelper shutting down *** ]")
hc.chaff.shutdown = true
break
}
}
time.Sleep(time.Duration(nextDuration) * time.Millisecond)
if hc.chaff.shutdown {
log.Println("*** chaffHelper shutting down")
} else {
log.Println("[ *** chaffHelper shutting down *** ]")
break
}
time.Sleep(time.Duration(nextDuration) * time.Millisecond)
}
}()
}
func (hc *Conn) StartupKeepAlive() {
hc.ResetKeepAlive()
log.Println("KeepAlive ENABLED")
hc.keepaliveHelper()
}
func (hc *Conn) ShutdownKeepAlive() {
log.Println("Conn SHUTDOWN")
hc.Close()
}
func (hc *Conn) ResetKeepAlive() {
hc.keepalive = 3
log.Println("KeepAlive RESET")
}
// Helper routine to spawn a keepalive goroutine for each Conn
func (hc *Conn) keepaliveHelper() {
go func() {
for {
nextDuration := 10000
bufTmp := []byte{0x55, 0xaa}
_, err := hc.WritePacket(bufTmp, CSOKeepAlive)
logger.LogDebug(fmt.Sprintf("[keepalive]\n"))
if err != nil {
logger.LogDebug(fmt.Sprintf("[ *** error - keepaliveHelper quitting *** ]\n"))
break
}
time.Sleep(time.Duration(nextDuration) * time.Millisecond)
hc.keepalive -= 1
logger.LogDebug(fmt.Sprintf("[keepAlive is now %d]\n", hc.keepalive))
//if rand.Intn(8) == 0 {
// hc.keepalive = 0
//}
if hc.keepalive == 0 {
logger.LogDebug(fmt.Sprintf("*** keepaliveHelper shutting down\n"))
hc.SetStatus(CSEConnDead)
hc.ShutdownKeepAlive()
if hc.Pproc != 0 {
//fmt.Printf("[pid %d needs to be killed]\n", hc.Pproc)
syscall.Kill(hc.Pproc, syscall.SIGABRT) //nolint:errcheck
}
break
}
}
}()
}