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| author | Roland Shoemaker <roland@golang.org> | 2022-03-02 08:24:15 -0800 |
|---|---|---|
| committer | Filippo Valsorda <filippo@golang.org> | 2022-03-12 13:11:42 +0000 |
| commit | 6068a2e6cfdc895ce524b6d2bdc8ea0cea8ea0e8 (patch) | |
| tree | fed73256d9872634836f5ad94e8e3ff1a11cc52f /ssh/common.go | |
| parent | efcb8507fb706dc09498bdd32b7aafa38228fc86 (diff) | |
| download | go-x-crypto-6068a2e6cfdc895ce524b6d2bdc8ea0cea8ea0e8.tar.xz | |
ssh: ignore MAC if AEAD ciphers negotiated
If the server/client cipher chosen is one of the two AEAD ciphers that
we support (aes128-gcm@openssh.com and chacha20-poly1305@openssh.com),
don't attempt to find a common MAC algorithm in findAgreedAlgorithms.
Similarly in newPacketCipher, don't attempt to generate a MAC key if we
are using a AEAD cipher.
Fixes golang/go#51406
Change-Id: Id48ae72f052cb0a0c597b32e9901a0f218e4161f
Reviewed-on: https://go-review.googlesource.com/c/crypto/+/389214
Trust: Roland Shoemaker <roland@golang.org>
Run-TryBot: Roland Shoemaker <roland@golang.org>
TryBot-Result: Gopher Robot <gobot@golang.org>
Reviewed-by: Filippo Valsorda <filippo@golang.org>
Diffstat (limited to 'ssh/common.go')
| -rw-r--r-- | ssh/common.go | 21 |
1 files changed, 15 insertions, 6 deletions
diff --git a/ssh/common.go b/ssh/common.go index 5ae2275..ec1f839 100644 --- a/ssh/common.go +++ b/ssh/common.go @@ -152,6 +152,11 @@ func (a *directionAlgorithms) rekeyBytes() int64 { return 1 << 30 } +var aeadCiphers = map[string]bool{ + gcmCipherID: true, + chacha20Poly1305ID: true, +} + type algorithms struct { kex string hostKey string @@ -187,14 +192,18 @@ func findAgreedAlgorithms(isClient bool, clientKexInit, serverKexInit *kexInitMs return } - ctos.MAC, err = findCommon("client to server MAC", clientKexInit.MACsClientServer, serverKexInit.MACsClientServer) - if err != nil { - return + if !aeadCiphers[ctos.Cipher] { + ctos.MAC, err = findCommon("client to server MAC", clientKexInit.MACsClientServer, serverKexInit.MACsClientServer) + if err != nil { + return + } } - stoc.MAC, err = findCommon("server to client MAC", clientKexInit.MACsServerClient, serverKexInit.MACsServerClient) - if err != nil { - return + if !aeadCiphers[stoc.Cipher] { + stoc.MAC, err = findCommon("server to client MAC", clientKexInit.MACsServerClient, serverKexInit.MACsServerClient) + if err != nil { + return + } } ctos.Compression, err = findCommon("client to server compression", clientKexInit.CompressionClientServer, serverKexInit.CompressionClientServer) |