diff options
| -rw-r--r-- | ssh/common.go | 8 | ||||
| -rw-r--r-- | ssh/kex.go | 12 | ||||
| -rw-r--r-- | ssh/kex_test.go | 41 | ||||
| -rw-r--r-- | ssh/test/session_test.go | 3 |
4 files changed, 61 insertions, 3 deletions
diff --git a/ssh/common.go b/ssh/common.go index 3862ec8..b419c76 100644 --- a/ssh/common.go +++ b/ssh/common.go @@ -49,7 +49,8 @@ var supportedKexAlgos = []string{ // P384 and P521 are not constant-time yet, but since we don't // reuse ephemeral keys, using them for ECDH should be OK. kexAlgoECDH256, kexAlgoECDH384, kexAlgoECDH521, - kexAlgoDH14SHA256, kexAlgoDH14SHA1, kexAlgoDH1SHA1, + kexAlgoDH14SHA256, kexAlgoDH16SHA512, kexAlgoDH14SHA1, + kexAlgoDH1SHA1, } // serverForbiddenKexAlgos contains key exchange algorithms, that are forbidden @@ -59,8 +60,9 @@ var serverForbiddenKexAlgos = map[string]struct{}{ kexAlgoDHGEXSHA256: {}, // server half implementation is only minimal to satisfy the automated tests } -// preferredKexAlgos specifies the default preference for key-exchange algorithms -// in preference order. +// preferredKexAlgos specifies the default preference for key-exchange +// algorithms in preference order. The diffie-hellman-group16-sha512 algorithm +// is disabled by default because it is a bit slower than the others. var preferredKexAlgos = []string{ kexAlgoCurve25519SHA256, kexAlgoCurve25519SHA256LibSSH, kexAlgoECDH256, kexAlgoECDH384, kexAlgoECDH521, @@ -23,6 +23,7 @@ const ( kexAlgoDH1SHA1 = "diffie-hellman-group1-sha1" kexAlgoDH14SHA1 = "diffie-hellman-group14-sha1" kexAlgoDH14SHA256 = "diffie-hellman-group14-sha256" + kexAlgoDH16SHA512 = "diffie-hellman-group16-sha512" kexAlgoECDH256 = "ecdh-sha2-nistp256" kexAlgoECDH384 = "ecdh-sha2-nistp384" kexAlgoECDH521 = "ecdh-sha2-nistp521" @@ -430,6 +431,17 @@ func init() { hashFunc: crypto.SHA256, } + // This is the group called diffie-hellman-group16-sha512 in RFC + // 8268 and Oakley Group 16 in RFC 3526. + p, _ = new(big.Int).SetString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kexAlgoMap[kexAlgoDH16SHA512] = &dhGroup{ + g: new(big.Int).SetInt64(2), + p: p, + pMinus1: new(big.Int).Sub(p, bigOne), + hashFunc: crypto.SHA512, + } + kexAlgoMap[kexAlgoECDH521] = &ecdh{elliptic.P521()} kexAlgoMap[kexAlgoECDH384] = &ecdh{elliptic.P384()} kexAlgoMap[kexAlgoECDH256] = &ecdh{elliptic.P256()} diff --git a/ssh/kex_test.go b/ssh/kex_test.go index 327013b..cb7f66a 100644 --- a/ssh/kex_test.go +++ b/ssh/kex_test.go @@ -8,6 +8,7 @@ package ssh import ( "crypto/rand" + "fmt" "reflect" "sync" "testing" @@ -63,3 +64,43 @@ func TestKexes(t *testing.T) { }) } } + +func BenchmarkKexes(b *testing.B) { + type kexResultErr struct { + result *kexResult + err error + } + + for name, kex := range kexAlgoMap { + b.Run(name, func(b *testing.B) { + for i := 0; i < b.N; i++ { + t1, t2 := memPipe() + + s := make(chan kexResultErr, 1) + c := make(chan kexResultErr, 1) + var magics handshakeMagics + + go func() { + r, e := kex.Client(t1, rand.Reader, &magics) + t1.Close() + c <- kexResultErr{r, e} + }() + go func() { + r, e := kex.Server(t2, rand.Reader, &magics, testSigners["ecdsa"].(AlgorithmSigner), testSigners["ecdsa"].PublicKey().Type()) + t2.Close() + s <- kexResultErr{r, e} + }() + + clientRes := <-c + serverRes := <-s + + if clientRes.err != nil { + panic(fmt.Sprintf("client: %v", clientRes.err)) + } + if serverRes.err != nil { + panic(fmt.Sprintf("server: %v", serverRes.err)) + } + } + }) + } +} diff --git a/ssh/test/session_test.go b/ssh/test/session_test.go index b44877e..4745ed9 100644 --- a/ssh/test/session_test.go +++ b/ssh/test/session_test.go @@ -410,6 +410,9 @@ func TestKeyExchanges(t *testing.T) { // are not included in the default list of supported kex so we have to add them // here manually. kexOrder = append(kexOrder, "diffie-hellman-group-exchange-sha1", "diffie-hellman-group-exchange-sha256") + // The key exchange algorithms diffie-hellman-group16-sha512 is disabled by + // default so we add it here manually. + kexOrder = append(kexOrder, "diffie-hellman-group16-sha512") for _, kex := range kexOrder { t.Run(kex, func(t *testing.T) { server := newServer(t) |