Unify signing codepath of ssl3_send_client_verify.

Instead of, in the pre-TLS-1.2 case, reaching into the EVP and manually
signing, compute the digest separately from signing. Then use EVP_PKEY_sign.
This will make it easier to implement https://crbug.com/347404 by having only
one signing codepath as well as make that logic simpler.

Also add a bounds check while we're here, although the buffer is too large to
actually matter.

runner.go client auth tests should cover code changes.

Change-Id: I7d87181bbcc5a761660412452e508d24c4725327
Reviewed-on: https://boringssl-review.googlesource.com/1122
Reviewed-by: Adam Langley <agl@google.com>
1 file changed