Tidy cipher rule processing.

Rather than shoehorn real ciphers and cipher aliases into the same type (that's
what cipher->valid is used for), treat them separately. Make
ssl_cipher_apply_rule match ciphers by cipher_id (the parameter was ignored and
we assumed that masks uniquely identify a cipher) and remove the special cases
around zero for all the masks. This requires us to remember which fields
default to 0 and which default to ~0u, but the logic is much clearer.

Finally, now that ciphers and cipher aliases are different, don't process rules
which sum together an actual cipher with cipher aliases. This would AND
together the masks for the alias with the values in the cipher and do something
weird around alg_ssl. (alg_ssl is just weird in general, as everyone trying to
disable SSLv3 in OpenSSL recently discovered.)

With all that, we can finally remove cipher->valid which was always one.

Change-Id: Iefcfe159bd6c22dbaea3a5f1517bd82f756dcfe1
Reviewed-on: https://boringssl-review.googlesource.com/4284
Reviewed-by: Adam Langley <agl@google.com>
5 files changed