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xs
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Merge branch 'remodulate-on-rekey' of RLabs/xs into master 

Add optional cipher/hmac algo remodulate on rekey
This commit is contained in:
Russtopia 2023-12-02 02:00:17 -08:00 committed by Gogs
parent e82d968381 32b669192b
commit faf8769ac4
6 changed files with 103 additions and 11 deletions
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2
Makefile
View File

@ -1,4 +1,4 @@
VERSION := 0.9.6
VERSION := 0.9.7
.PHONY: lint vis clean common client server passwd\
subpkgs install uninstall reinstall scc

12
xs/xs.go
View File

@ -702,6 +702,7 @@ func main() { //nolint: funlen, gocyclo
cmdStr string
tunSpecStr string // lport1:rport1[,lport2:rport2,...]
rekeySecs uint
remodRequested bool // true: when rekeying, switch to random cipher/hmac alg
copySrc []byte
copyDst string
copyQuiet bool
@ -745,8 +746,9 @@ func main() { //nolint: funlen, gocyclo
KEX_FRODOKEM_976AES
KEX_FRODOKEM_976SHAKE`)
flag.StringVar(&kcpMode, "K", "unused", "KCP `alg`, 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") //nolint:lll
flag.UintVar(&port, "p", 2000, "``port") //nolint:gomnd,lll
flag.UintVar(&port, "p", 2000, "``port") //nolint:gomnd,lll
flag.UintVar(&rekeySecs, "r", 300, "rekey interval in `secs`")
flag.BoolVar(&remodRequested, "R", false, "Borg Countermeasures (remodulate cipher/hmac alg on each rekey)")
//nolint:gocritic,nolintlint // flag.StringVar(&authCookie, "a", "", "auth cookie")
flag.BoolVar(&chaffEnabled, "e", true, "enable chaff pkts")
flag.UintVar(&chaffFreqMin, "f", 100, "chaff pkt freq min `msecs`") //nolint:gomnd
@ -967,7 +969,13 @@ func main() { //nolint: funlen, gocyclo
if kcpMode != "unused" {
proto = "kcp"
}
conn, err := xsnet.Dial(proto, server, cipherAlg, hmacAlg, kexAlg, kcpMode)
remodExtArg := ""
if remodRequested {
remodExtArg = "OPT_REMOD"
}
// Pass opt to Dial() via extensions arg
conn, err := xsnet.Dial(proto, server, cipherAlg, hmacAlg, kexAlg, kcpMode, remodExtArg)
if err != nil {
fmt.Println(err)
exitWithStatus(XSNetDialFailed)

20
xsd/xsd.go
View File

@ -530,12 +530,14 @@ func main() { //nolint:funlen,gocyclo
var dbg bool
var laddr string
var rekeySecs uint
var remodSupported bool // true: when rekeying, switch to random cipher/hmac alg
var useSystemPasswd bool
flag.BoolVar(&vopt, "v", false, "show version")
flag.UintVar(&rekeySecs, "r", 300, "rekey interval in `secs`")
flag.StringVar(&laddr, "l", ":2000", "interface[:port] to listen") //nolint:gomnd,lll
flag.BoolVar(&remodSupported, "R", false, "Borg Countermeasures (remodulate cipher/hmac alg on each rekey)")
flag.StringVar(&laddr, "l", ":2000", "interface[:port] to listen") //nolint:gomnd,lll
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`) //nolint:lll
flag.BoolVar(&useSysLogin, "L", false, "use system login")
flag.BoolVar(&chaffEnabled, "e", true, "enable chaff pkts")
@ -702,6 +704,22 @@ func main() { //nolint:funlen,gocyclo
} else {
log.Println("Accepted client")
// Only enable cipher alg changes on re-key if we were told
// to support it (launching xsd with -R), *and* the client
// proposes to use it.
if !remodSupported {
if (conn.Opts() & xsnet.CORemodulateShields) != 0 {
logger.LogDebug("[client proposed cipher/hmac remod, but we don't support it.]")
conn.Close()
continue
}
} else {
if conn.Opts()&xsnet.CORemodulateShields != 0 {
logger.LogDebug("[cipher/hmac remodulation active]")
} else {
logger.LogDebug("[cipher/hmac remodulation inactive]")
}
}
conn.RekeyHelper(rekeySecs)
// Set up chaffing to client

17
xsnet/chan.go
View File

@ -22,6 +22,7 @@ import (
"blitter.com/go/cryptmt"
"blitter.com/go/hopscotch"
"blitter.com/go/xs/logger"
"github.com/aead/chacha20/chacha"
"golang.org/x/crypto/blowfish"
"golang.org/x/crypto/twofish"
@ -57,9 +58,19 @@ func expandKeyMat(keymat []byte, blocksize int) []byte {
return keymat
}
/* (Re-)initialize the keystream and hmac state for an xsnet.Conn, returning
a cipherStream and hash
*/
// Choose a cipher and hmac alg from supported sets, given two uint8 values
func getNewStreamAlgs(cb uint8, hb uint8) (config uint32) {
// Get new cipher and hash algs (clamped to valid values) based on
// the input rekeying data
c := (cb % CAlgNoneDisallowed)
h := (hb % HmacNoneDisallowed)
config = uint32(h<<8) | uint32(c)
logger.LogDebug(fmt.Sprintf("[Chose new algs [%d:%d]", h, c))
return
}
// (Re-)initialize the keystream and hmac state for an xsnet.Conn, returning
// a cipherStream and hash
func (hc *Conn) getStream(keymat []byte) (rc cipher.Stream, mc hash.Hash, err error) {
var key []byte
var block cipher.Block

14
xsnet/consts.go
View File

@ -122,5 +122,19 @@ const (
HmacNoneDisallowed
)
// Conn opts outside of basic kex/cipher/hmac connect config
const (
CONone = iota
CORemodulateShields // if set, rekeying also reselects random cipher/hmac alg
)
type COValue uint32
// Available HMACs for hkex.Conn
type CSHmacAlg uint32
// Some bounds-checking consts
const (
REKEY_SECS_MIN = 1
CHAFF_FREQ_MSECS_MIN = 1
)

49
xsnet/net.go
View File

@ -241,7 +241,7 @@ func (hc *Conn) SetConnOpts(copts uint32) {
//
// Consumers of this lib may use this for protocol-level options not part
// of the KEx or encryption info used by the connection.
func (hc Conn) Opts() uint32 {
func (hc *Conn) Opts() uint32 {
return hc.opts
}
@ -363,6 +363,9 @@ func (hc *Conn) applyConnExtensions(extensions ...string) {
log.Println("[extension arg = H_SHA512]")
hc.cipheropts &= (0xFFFF00FF)
hc.cipheropts |= (HmacSHA512 << 8)
case "OPT_REMOD":
log.Println("[extension arg = OPT_REMOD]")
hc.opts |= CORemodulateShields
//default:
// log.Printf("[Dial ext \"%s\" ignored]\n", s)
}
@ -1351,6 +1354,11 @@ func (hc *Conn) Read(b []byte) (n int, err error) {
//logger.LogDebug(fmt.Sprintf("[Got rekey [%02x %02x %02x ...]\n",
// payloadBytes[0], payloadBytes[1], payloadBytes[2]))
rekeyData := payloadBytes
if (hc.opts & CORemodulateShields) != 0 {
hc.Lock()
hc.cipheropts = getNewStreamAlgs(rekeyData[0], rekeyData[1])
hc.Unlock()
}
hc.r, hc.rm, err = hc.getStream(rekeyData)
case CSOTermSize:
fmt.Sscanf(string(payloadBytes), "%d %d", &hc.Rows, &hc.Cols)
@ -1585,7 +1593,9 @@ func (hc *Conn) StartupChaff() {
}
func (hc *Conn) ShutdownChaff() {
hc.Lock()
hc.chaff.shutdown = true
hc.Unlock()
log.Println("Chaffing SHUTDOWN")
}
@ -1596,16 +1606,28 @@ func (hc *Conn) SetupChaff(msecsMin uint, msecsMax uint, szMax uint) {
}
func (hc *Conn) ShutdownRekey() {
hc.Lock()
hc.rekey = 0
hc.Unlock()
}
func (hc *Conn) RekeyHelper(intervalSecs uint) {
if intervalSecs < REKEY_SECS_MIN {
intervalSecs = REKEY_SECS_MIN
}
go func() {
hc.Lock()
hc.rekey = intervalSecs
hc.Unlock()
for {
if hc.rekey != 0 {
hc.Lock()
rekey := hc.rekey
hc.Unlock()
if rekey != 0 {
//logger.LogDebug(fmt.Sprintf("[rekeyHelper Loop]\n"))
time.Sleep(time.Duration(hc.rekey) * time.Second)
time.Sleep(time.Duration(rekey) * time.Second)
// Send rekey to other end
rekeyData := make([]byte, 64)
@ -1615,6 +1637,9 @@ func (hc *Conn) RekeyHelper(intervalSecs uint) {
//logger.LogDebug("[+rekeyHelper]")
_, err = hc.WritePacket(rekeyData, CSORekey)
hc.Lock()
if (hc.opts & CORemodulateShields) != 0 {
hc.cipheropts = getNewStreamAlgs(rekeyData[0], rekeyData[1])
}
hc.w, hc.wm, err = hc.getStream(rekeyData)
//logger.LogDebug("[-rekeyHelper]")
hc.Unlock()
@ -1631,11 +1656,21 @@ func (hc *Conn) RekeyHelper(intervalSecs uint) {
// Helper routine to spawn a chaffing goroutine for each Conn
func (hc *Conn) chaffHelper() {
// Enforce bounds on chaff frequency and pkt size
hc.Lock()
if hc.chaff.msecsMin < CHAFF_FREQ_MSECS_MIN {
hc.chaff.msecsMin = CHAFF_FREQ_MSECS_MIN
}
hc.Unlock()
go func() {
var nextDuration int
for {
//logger.LogDebug(fmt.Sprintf("[chaffHelper Loop]\n"))
if !hc.chaff.shutdown {
hc.Lock()
shutdown := hc.chaff.shutdown
hc.Unlock()
if !shutdown {
var bufTmp []byte
bufTmp = make([]byte, rand.Intn(int(hc.chaff.szMax)))
min := int(hc.chaff.msecsMin)
@ -1646,7 +1681,9 @@ func (hc *Conn) chaffHelper() {
//logger.LogDebug("[-chaffHelper]")
if err != nil {
log.Println("[ *** error - chaffHelper shutting down *** ]")
hc.Lock()
hc.chaff.shutdown = true
hc.Unlock()
break
}
} else {
@ -1670,7 +1707,9 @@ func (hc *Conn) ShutdownKeepAlive() {
}
func (hc *Conn) ResetKeepAlive() {
hc.Lock()
hc.keepalive = 3
hc.Unlock()
log.Println("KeepAlive RESET")
}
@ -1689,7 +1728,9 @@ func (hc *Conn) keepaliveHelper() {
break
}
time.Sleep(time.Duration(nextDuration) * time.Millisecond)
hc.Lock()
hc.keepalive -= 1
hc.Unlock()
//logger.LogDebug(fmt.Sprintf("[keepAlive is now %d]\n", hc.keepalive))
//if rand.Intn(8) == 0 {