Since we are eliminating DHE support in TLS, this is just a waste of
bytes.

Change-Id: I3a23ece564e43f7e8874d1ec797def132ba59504
Reviewed-on: https://boringssl-review.googlesource.com/10260
Reviewed-by: Adam Langley <agl@google.com>
Commit-Queue: Adam Langley <agl@google.com>
CQ-Verified: CQ bot account: commit-bot@chromium.org <commit-bot@chromium.org>

As of 67cb49d045 and the corresponding upstream
change, BN_mod_word may fail, like BN_div_word. Handle this properly and
document in bn.h. Thanks to Brian Smith for pointing this out.

Change-Id: I6d4f32dc37bcabf70847c9a8b417d55d31b3a380
Reviewed-on: https://boringssl-review.googlesource.com/8491
Reviewed-by: Adam Langley <agl@google.com>

This function returns a tri-state -1 on error. We should check this.

Change-Id: I6fe130c11d10690923aac5ac7a6dfe3e3ff3f5e9
Reviewed-on: https://boringssl-review.googlesource.com/8490
Reviewed-by: Adam Langley <agl@google.com>

This is CVE-2016-0701 for OpenSSL, reported by Antonio Sanso. It is a no-op for
us as we'd long removed SSL_OP_DH_SINGLE_USE and static DH cipher suites. (We
also do not parse or generate X9.42 DH parameters.)

However, we do still have the APIs which return RFC 5114 groups, so we should
perform the necessary checks in case later consumers reuse keys.

Unlike groups we generate, RFC 5114 groups do not use "safe primes" and have
many small subgroups. In those cases, the subprime q is available. Before using
a public key, ensure its order is q by checking y^q = 1 (mod p). (q is assumed
to be prime and the existing range checks ensure y is not 1.)

(Imported from upstream's 878e2c5b13 and
75374adf8a6ff69d6718952121875a491ed2cd29, but with some bugs fixed. See
RT4278.)

Change-Id: Ib18c3e84819002fa36a127ac12ca00ee33ea018a
Reviewed-on: https://boringssl-review.googlesource.com/7001
Reviewed-by: Adam Langley <agl@google.com>

(Imported from upstream's fe69e6be6e)

Initial fork from f2d678e6e8 (1.0.2 beta).

(This change contains substantial changes from the original and
effectively starts a new history.)