tree e2ab277420995401e20dd2095b4bb798b89c1098
parent 1d75c8be73e5e78220498b182c629c46d7e524af
author Eric Roman <eroman@chromium.org> 1422316335 -0800
committer Adam Langley <agl@google.com> 1422408445 +0000

Initialize HMAC keys to zero.

In an attempt to assign a zero-length HMAC key, consumers might
incorrectly call:

   HMAC_Init_ex(key=NULL, key_len=0)

This does not work as expected since |key==NULL| has special semantics.
This bug may consequently result in uninitialized memory being used for
the HMAC key data.

This workaround doesn't fix all the problems associated with this
pattern, however by defaulting to a zero key the results are more
predictable than before.

BUG=http://crbug.com/449409

Change-Id: I777276d57c61f1c0cce80b18e28a9b063784733f
Reviewed-on: https://boringssl-review.googlesource.com/3040
Reviewed-by: Adam Langley <agl@google.com>