Add support to QUIC for QUIC_VERSION_8: for RSA-PSS signatures, set

Add support to QUIC for QUIC_VERSION_8: for RSA-PSS signatures, set
the salt length to the digest length.

This is recommended by RFC 4055, Section 3.1:

saltLength

  The saltLength field is the octet length of the salt.  For a
  given hashAlgorithm, the recommended value of saltLength is the
  number of octets in the hash value.  ...

OpenSSL's default salt length is the special value -2. When signing,
-2 sets the salt length to the maximum permissible value. When
verifying, -2 causes the salt length to be automatically determined
based on the PSS block structure.

Merge internal CL: 50532662

R=rch@chromium.org,rtenneti@chromium.org
BUG=none
TEST=net_unittests

Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=216608

[wtc, 2013-08-08 00:37:33]

rch: please review.

ramant: just FYI. I am porting this CL of mine myself.

https://codereview.chromium.org/22647002/diff/20001/net/quic/crypto/proof_ver...
File net/quic/crypto/proof_verifier_chromium.cc (right):

https://codereview.chromium.org/22647002/diff/20001/net/quic/crypto/proof_ver...
net/quic/crypto/proof_verifier_chromium.cc:202: version >= QUIC_VERSION_8 ?
hash_len : signature.size() - hash_len - 2;

This is the most important change, which selects the salt length based on the
Quic version.

[Ryan Hamilton, 2013-08-08 03:52:02]

lgtm

[commit-bot: I haz the power, 2013-08-08 17:30:01]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/wtc@chromium.org/22647002/20001

[commit-bot: I haz the power, 2013-08-09 06:38:38]

Change committed as 216608