Enable TLS padding extension using official value from:

http://www.iana.org/assignments/tls-extensiontype-values/tls-extensiontype-values.xhtml

Security callback: selects which parameters are permitted including
sensible defaults based on bits of security.

The "parameters" which can be selected include: ciphersuites,
curves, key sizes, certificate signature algorithms, supported
signature algorithms, DH parameters, SSL/TLS version, session tickets
and compression.

In some cases prohibiting the use of a parameters will mean they are
not advertised to the peer: for example cipher suites and ECC curves.
In other cases it will abort the handshake: e.g DH parameters or the
peer key size.

Documentation to follow...

New function ssl_cipher_disabled.

Check for disabled client ciphers using ssl_cipher_disabled.

New function to return only supported ciphers.

New option to ciphers utility to print only supported ciphers.

Add auto DH parameter support. This is roughly equivalent to the
ECDH auto curve selection but for DH. An application can just call

SSL_CTX_set_auto_dh(ctx, 1);

and appropriate DH parameters will be used based on the size of the
server key.

Unlike ECDH there is no way a peer can indicate the range of DH parameters
it supports. Some peers cannot handle DH keys larger that 1024 bits for
example. In this case if you call:

SSL_CTX_set_auto_dh(ctx, 2);

Only 1024 bit DH parameters will be used.

If the server key is 7680 bits or more in size then 8192 bit DH parameters
will be used: these will be *very* slow.

The old export ciphersuites aren't supported but those are very
insecure anyway.

(cherry picked from commit bc5ec653ba65fedb1619c8182088497de8a97a70)

Add the extension parser in the s_client, ocsp and x509 apps.

The contract for custom extension callbacks has changed - all custom extension callbacks are triggered

Whitespace fixes

If multiple TLS extensions are expected but not received, the TLS extension and supplemental data 'generate' callbacks are the only chance for the receive-side to trigger a specific TLS alert during the handshake.

Removed logic which no-op'd TLS extension generate callbacks (as the generate callbacks need to always be called in order to trigger alerts), and updated the serverinfo-specific custom TLS extension callbacks to track which custom TLS extensions were received by the client, where no-ops for 'generate' callbacks are appropriate.

PR#3178

ECDHE is the standard term used by the RFCs and by other TLS
implementations.  It's useful to have the internal variables use the
standard terminology.

This patch leaves a synonym SSL_kEECDH in place, though, so that older
code can still be built against it, since that has been the
traditional API.  SSL_kEECDH should probably be deprecated at some
point, though.

(cherry picked from commit cfa86987a8d9d2b8cc5e5fea2d3260c46542cdb9)

Fix padding calculation for different SSL_METHOD types. Use the
standard name as used in draft-agl-tls-padding-02

PR#3106

Based on a suggested workaround for the "TLS hang bug" (see FAQ and PR#2771):
if the TLS Client Hello record length value would otherwise be > 255 and less
that 512 pad with a dummy extension containing zeroes so it is at least 512.

To enable it use an unused extension number (for example 0x4242) using
e.g. -DTLSEXT_TYPE_wtf=0x4242

WARNING: EXPERIMENTAL, SUBJECT TO CHANGE.

Don't require a public key in tls1_set_ec_id if compression status is
not needed. This fixes a bug where SSL_OP_SINGLE_ECDH_USE wouldn't work.
(cherry picked from commit 5ff68e8f6dac3b0d8997b8bc379f9111c2bab74f)

Removing RSA+MD5 from the default signature algorithm list
prevents its use by default.

If a broken implementation attempts to use RSA+MD5 anyway the sanity
checking of signature algorithms will cause a fatal alert.

Experimental support for encrypt then mac from
draft-gutmann-tls-encrypt-then-mac-02.txt

To enable it set the appropriate extension number (0x10 for the test server)
using e.g. -DTLSEXT_TYPE_encrypt_then_mac=0x10

For non-compliant peers (i.e. just about everything) this should have no
effect.

Add callbacks supporting generation and retrieval of supplemental data entries, facilitating RFC 5878 (TLS auth extensions)
Removed prior audit proof logic - audit proof support was implemented using the generic TLS extension API
Tests exercising the new supplemental data registration and callback api can be found in ssltest.c.
Implemented changes to s_server and s_client to exercise supplemental data callbacks via the -auth argument, as well as additional flags to exercise supplemental data being sent only during renegotiation.

OS X 10.8..10.8.3 has broken support for ECDHE-ECDSA ciphers.

Force no SSL2 when custom extensions in use.
Don't clear extension state when cert is set.
Clear on renegotiate.

This change adds support for ALPN[1] in OpenSSL. ALPN is the IETF
blessed version of NPN and we'll be supporting both ALPN and NPN for
some time yet.

[1] https://tools.ietf.org/html/draft-ietf-tls-applayerprotoneg-00

Conflicts:
	ssl/ssl3.h
	ssl/t1_lib.c

serverinfo rejects non-empty extensions.

Omit extension if no relevant serverinfo data.

Improve error-handling in serverinfo callback.

Cosmetic cleanups.

s_client documentation.

s_server documentation.

SSL_CTX_serverinfo documentation.

Cleaup -1 and NULL callback handling for custom extensions, add tests.

Cleanup ssl_rsa.c serverinfo code.

Whitespace cleanup.

Improve comments in ssl.h for serverinfo.

Whitespace.

Cosmetic cleanup.

Reject non-zero-len serverinfo extensions.

Whitespace.

Make it build.

Contributed by Trevor Perrin.

Since s->method does not reflect the final client version when a client
hello is sent for SSLv23_client_method it can't be relied on to indicate
if TLS 1.2 ciphers should be used. So use the client version instead.

Port TLS 1.2 GCM code to DTLS. Enable use of TLS 1.2 only ciphers when in
DTLS 1.2 mode too.

Some TLS extensions were disabled for DTLS. Possibly because they caused
problems with the old duplicated code. Enable them again.

Use the enc_flags field to determine whether we should use explicit IV,
signature algorithms or SHA256 default PRF instead of hard coding which
versions support each requirement.

Revise DTLS code. There was a *lot* of code duplication in the
DTLS code that generates records. This makes it harder to maintain and
sometimes a TLS update is omitted by accident from the DTLS code.

Specifically almost all of the record generation functions have code like
this:

some_pointer = buffer + HANDSHAKE_HEADER_LENGTH;
... Record creation stuff ...
set_handshake_header(ssl, SSL_MT_SOMETHING, message_len);

...

write_handshake_message(ssl);

Where the "Record creation stuff" is identical between SSL/TLS and DTLS or
in some cases has very minor differences.

By adding a few fields to SSL3_ENC to include the header length, some flags
and function pointers for handshake header setting and handshake writing the
code can cope with both cases.

Note: although this passes "make test" and some simple DTLS tests there may
be some minor differences in the DTLS code that have to be accounted for.

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.
(cherry picked from commit 2ee798880a246d648ecddadc5b91367bee4a5d98)