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| author | Roland Shoemaker <roland@golang.org> | 2021-11-09 11:45:57 -0800 |
|---|---|---|
| committer | Roland Shoemaker <roland@golang.org> | 2021-12-02 19:23:23 +0000 |
| commit | 5770296d904e90f15f38f77dfc2e43fdf5efc083 (patch) | |
| tree | 75fd3358961f563865bd18f66c721ede33ddf587 /ssh/cipher.go | |
| parent | ae814b36b87190c757eede9bc2d32ed77df88551 (diff) | |
| download | go-x-crypto-5770296d904e90f15f38f77dfc2e43fdf5efc083.tar.xz | |
ssh: don't assume packet plaintext size
When reading GCM and ChaChaPoly1305 packets, don't make assumptions
about the size of the enciphered plaintext. This fixes two panics
caused by standards non-compliant malformed packets.
Thanks to Rod Hynes, Psiphon Inc. for reporting this issue.
Fixes golang/go#49932
Fixes CVE-2021-43565
Change-Id: I660cff39d197e0d04ec44d11d792b22d954df2ef
Reviewed-on: https://team-review.git.corp.google.com/c/golang/go-private/+/1262659
Reviewed-by: Katie Hockman <katiehockman@google.com>
Reviewed-by: Julie Qiu <julieqiu@google.com>
Reviewed-on: https://go-review.googlesource.com/c/crypto/+/368814
Trust: Roland Shoemaker <roland@golang.org>
Trust: Katie Hockman <katie@golang.org>
Run-TryBot: Roland Shoemaker <roland@golang.org>
TryBot-Result: Gopher Robot <gobot@golang.org>
Reviewed-by: Julie Qiu <julie@golang.org>
Reviewed-by: Katie Hockman <katie@golang.org>
Diffstat (limited to 'ssh/cipher.go')
| -rw-r--r-- | ssh/cipher.go | 8 |
1 files changed, 8 insertions, 0 deletions
diff --git a/ssh/cipher.go b/ssh/cipher.go index bddbde5..f8bdf49 100644 --- a/ssh/cipher.go +++ b/ssh/cipher.go @@ -394,6 +394,10 @@ func (c *gcmCipher) readCipherPacket(seqNum uint32, r io.Reader) ([]byte, error) } c.incIV() + if len(plain) == 0 { + return nil, errors.New("ssh: empty packet") + } + padding := plain[0] if padding < 4 { // padding is a byte, so it automatically satisfies @@ -710,6 +714,10 @@ func (c *chacha20Poly1305Cipher) readCipherPacket(seqNum uint32, r io.Reader) ([ plain := c.buf[4:contentEnd] s.XORKeyStream(plain, plain) + if len(plain) == 0 { + return nil, errors.New("ssh: empty packet") + } + padding := plain[0] if padding < 4 { // padding is a byte, so it automatically satisfies |