This change updates the DTLS code to match the constant-time CBC
behaviour in the TLS.

The previous CBC patch was bugged in that there was a path through enc()
in s3_pkt.c/d1_pkt.c which didn't set orig_len. orig_len would be left
at the previous value which could suggest that the packet was a
sufficient length when it wasn't.

This patch makes the decoding of SSLv3 and TLS CBC records constant
time. Without this, a timing side-channel can be used to build a padding
oracle and mount Vaudenay's attack.

This patch also disables the stitched AESNI+SHA mode pending a similar
fix to that code.

In order to be easy to backport, this change is implemented in ssl/,
rather than as a generic AEAD mode. In the future this should be changed
around so that HMAC isn't in ssl/, but crypto/ as FIPS expects.

This change adds CRYPTO_memcmp, which compares two vectors of bytes in
an amount of time that's independent of their contents. It also changes
several MAC compares in the code to use this over the standard memcmp,
which may leak information about the size of a matching prefix.

PR: 2963 and a number of others

Submitted by: Dmitry Belyavsky, Seguei Leontiev
PR: 2821

traditional format uses MD5 which is prohibited in FIPS mode.

Submitted by: Pierre Delaage

Use -1 to check all extensions in CRLs.
Always set flag for freshest CRL.

Submitted by: jean-etienne.schwartz@bull.net

In OCSP_basic_varify return an error if X509_STORE_CTX_init fails.

Submitted by: Dmitry Belyavsky <beldmit@gmail.com>

Fix DH double free if parameter generation fails.

Submitted by: "Florian Rüchel" <florian.ruechel@ruhr-uni-bochum.de>

Correctly handle local machine keys in the capi ENGINE.