tree 861d3ec77cb508b298e0af4f247efb4a23a2f8e1
parent c0b9456f609ac7bd1d755817ffdbffd296f9dd04
author Manuel Pégourié-Gonnard <manuel.pegourie-gonnard@arm.com> 1513616699 +0100
committer Manuel Pégourié-Gonnard <manuel.pegourie-gonnard@arm.com> 1513674300 +0100

Fix SSLv3 MAC computation

In a previous PR (Fix heap corruption in implementation of truncated HMAC
extension #425) the place where MAC is computed was changed from the end of
the SSL I/O buffer to a local buffer (then (part of) the content of the local
buffer is either copied to the output buffer of compare to the input buffer).

Unfortunately, this change was made only for TLS 1.0 and later, leaving SSL
3.0 in an inconsistent state due to ssl_mac() still writing to the old,
hard-coded location, which, for MAC verification, resulted in later comparing
the end of the input buffer (containing the computed MAC) to the local buffer
(uninitialised), most likely resulting in MAC verification failure, hence no
interop (even with ourselves).

This commit completes the move to using a local buffer by using this strategy
for SSL 3.0 too. Fortunately ssl_mac() was static so it's not a problem to
change its signature.