Add correct flags for DTLS 1.2, update s_server and s_client to handle
DTLS 1.2 methods.

Currently no support for version negotiation: i.e. if client/server selects
DTLS 1.2 it is that or nothing.

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.

perform sanity checks on server certificate type as soon as it is received instead of waiting until server key exchange

by a certificate chain. Add additional tests to handle client
certificates: checks for matching certificate type and issuer name
comparison.

Print out results of checks for each candidate chain tested in
s_server/s_client.

that are disabled for this session (as opposed to always disabled by
configuration).

details in s_client.

Also add ctrl to set client certificate types. If not used sensible values
will be included based on supported signature algorithms: for example if
we don't include any DSA signing algorithms the DSA certificate type is
omitted.

Fix restriction in old code where certificate types would be truncated
if it exceeded TLS_CT_NUMBER.

is required by client or server. An application can decide which
certificate chain to present based on arbitrary criteria: for example
supported signature algorithms. Add very simple example to s_server.
This fixes many of the problems and restrictions of the existing client
certificate callback: for example you can now clear existing certificates
and specify the whole chain.

Reviewed by: steve
Improved localisation of TLS extension handling and code tidy.

If OPENSSL_MAX_TLS1_2_CIPHER_LENGTH is set then limit the size of client
ciphersuites to this value. A value of 50 should be sufficient.

Document workarounds in CHANGES.

some servers.

certificate chain instead of an X509 structure.

This makes it easier to enhance code in future and the chain
output functions have access to the CERT_PKEY structure being
used.

The cipher definitions of these ciphersuites have been around since SSLeay
but were always disabled. Now OpenSSL supports DH certificates they can be
finally enabled.

Various additional changes were needed to make them work properly: many
unused fixed DH sections of code were untested.

Submitted by: Robin Seggelmann <seggelmann@fh-muenster.de>
Reviewed by: steve

Support for TLS/DTLS heartbeats.

Submitted by: Tianjie Mao <tjmao@tjmao.net>
Reviewed by: steve

Fix incorrect comma expressions and goto f_err as alert has been set.

Submitted by: Peter Sylvester <peter.sylvester@edelweb.fr>
Reviewed by: steve

Make SRP conformant to rfc 5054.

Changes are:

- removal of the addition state after client hello
- removal of all pre-rfc srp alert ids
- sending a fatal alert when there is no srp extension but when the
server wants SRP
- removal of unnecessary code in the client.

(Problem pointed out by Ben Murphy.)

Submitted by: Adam Langley

prohibit use of these ciphersuites for TLS < 1.2

Parse certificate request message and set digests appropriately.

Generate new TLS v1.2 format certificate verify message.

Keep handshake caches around for longer as they are needed for client auth.

Make sure message is long enough for signature algorithms.

algorithms extension (including everything we support). Swicth to new
signature format where needed and relax ECC restrictions.

Not TLS v1.2 client certifcate support yet but client will handle case
where a certificate is requested and we don't have one.

is picked up.

Submitted by: Mounir IDRASSI <mounir.idrassi@idrix.net>
Reviewed by: steve

Fix for double free bug in ssl/s3_clnt.c CVE-2010-2939