ssh: allow up to 255 bytes of padding in AES-GCM

The writing side would generate a maximum of 19 bytes of padding, so
the reading side erroneously checked this. However, RFC 5647 specifies
255 as the maximum amount of padding for AES-GCM.

Fixes golang/go#18953.

Change-Id: I416b0023c6e4cbd91a6a1b4214a03f1663b77248
Reviewed-by: Adam Langley <>
Run-TryBot: Adam Langley <>
TryBot-Result: Gobot Gobot <>
1 file changed