This commit changes the way that we do server side protocol version
negotiation. Previously we had a whole set of code that had an "up front"
state machine dedicated to the negotiating the protocol version. This adds
significant complexity to the state machine. Historically the justification
for doing this was the support of SSLv2 which works quite differently to
SSLv3+. However, we have now removed support for SSLv2 so there is little
reason to maintain this complexity.

The one slight difficulty is that, although we no longer support SSLv2, we
do still support an SSLv3+ ClientHello in an SSLv2 backward compatible
ClientHello format. This is generally only used by legacy clients. This
commit adds support within the SSLv3 code for these legacy format
ClientHellos.

Server side version negotiation now works in much the same was as DTLS,
i.e. we introduce the concept of TLS_ANY_VERSION. If s->version is set to
that then when a ClientHello is received it will work out the most
appropriate version to respond with. Also, SSLv23_method and
SSLv23_server_method have been replaced with TLS_method and
TLS_server_method respectively. The old SSLv23* names still exist as
macros pointing at the new name, although they are deprecated.

Subsequent commits will look at client side version negotiation, as well of
removal of the old s23* code.
Reviewed-by: NKurt Roeckx <kurt@openssl.org>

Just as with the OPENSSL_malloc calls, consistently use sizeof(*ptr)
for memset and memcpy.  Remove needless casts for those functions.
For memset, replace alternative forms of zero with 0.
Reviewed-by: NRichard Levitte <levitte@openssl.org>

Reviewed-by: Andy Polyakov

Reviewed-by: NMatt Caswell <matt@openssl.org>

Fix a "&" that should have been "!" when processing read_ahead.

RT#3793
Reviewed-by: NRich Salz <rsalz@openssl.org>
Reviewed-by: NRichard Levitte <levitte@openssl.org>

Fix up various things that were missed during the record layer work. All
instances where we are breaking the encapsulation rules.
Reviewed-by: NRichard Levitte <levitte@openssl.org>

Reviewed-by: NRichard Levitte <levitte@openssl.org>

Reviewed-by: NRichard Levitte <levitte@openssl.org>

Reviewed-by: NRichard Levitte <levitte@openssl.org>

Reviewed-by: NRichard Levitte <levitte@openssl.org>

Reviewed-by: NRichard Levitte <levitte@openssl.org>

Reviewed-by: NRichard Levitte <levitte@openssl.org>

Reviewed-by: NRichard Levitte <levitte@openssl.org>

alert_fragment_len from s->s3 into s->rlayer
Reviewed-by: NRichard Levitte <levitte@openssl.org>

Reviewed-by: NRichard Levitte <levitte@openssl.org>

Reviewed-by: NRichard Levitte <levitte@openssl.org>

Reviewed-by: NRichard Levitte <levitte@openssl.org>

layer
Reviewed-by: NRichard Levitte <levitte@openssl.org>

up some access to them. Now that various functions have been moved into the
record layer they no longer need to use the accessor macros.
Reviewed-by: NRichard Levitte <levitte@openssl.org>

Reviewed-by: NRichard Levitte <levitte@openssl.org>

Reviewed-by: NRichard Levitte <levitte@openssl.org>

Reviewed-by: NRichard Levitte <levitte@openssl.org>

Reviewed-by: NRichard Levitte <levitte@openssl.org>

RECORD_LAYER_write_pending.
Reviewed-by: NRichard Levitte <levitte@openssl.org>

Reviewed-by: NRichard Levitte <levitte@openssl.org>

Reviewed-by: NRichard Levitte <levitte@openssl.org>

the new files s3_msg.c and s1_msg.c respectively.
Reviewed-by: NRichard Levitte <levitte@openssl.org>

Reviewed-by: NRichard Levitte <levitte@openssl.org>

Reviewed-by: NRichard Levitte <levitte@openssl.org>

Reviewed-by: NRichard Levitte <levitte@openssl.org>

Reviewed-by: NRichard Levitte <levitte@openssl.org>

Reviewed-by: NRichard Levitte <levitte@openssl.org>

Reviewed-by: NRichard Levitte <levitte@openssl.org>

Ensure that all functions have their return values checked where
appropriate. This covers all functions defined and called from within
libssl.
Reviewed-by: NRichard Levitte <levitte@openssl.org>

OpenSSL 1.0.2 introduced the "multiblock" performance improvement. This
feature only applies on 64 bit x86 architecture platforms that support AES
NI instructions. A defect in the implementation of "multiblock" can cause
OpenSSL's internal write buffer to become incorrectly set to NULL when
using non-blocking IO. Typically, when the user application is using a
socket BIO for writing, this will only result in a failed connection.
However if some other BIO is used then it is likely that a segmentation
fault will be triggered, thus enabling a potential DoS attack.

CVE-2015-0290
Reviewed-by: NRichard Levitte <levitte@openssl.org>
Reviewed-by: NAndy Polyakov <appro@openssl.org>

This patch uses warning/fatal constants instead of numbers with comments for
warning/alerts in d1_pkt.c and s3_pkt.c

RT#3725
Reviewed-by: NRich Salz <rsalz@openssl.org>

Miscellaneous unchecked malloc fixes. Also fixed some mem leaks on error
paths as I spotted them along the way.
Reviewed-by: NTim Hudson <tjh@openssl.org>

I left many "#if 0" lines, usually because I thought we would
probably want to revisit them later, or because they provided
some useful internal documentation tips.
Reviewed-by: NAndy Polyakov <appro@openssl.org>

A few minor cleanups to remove pre-processor "#if 1" stuff.
Reviewed-by: NRichard Levitte <levitte@openssl.org>

TLS and TLS1 are no longer optional.
Reviewed-by: NRichard Levitte <levitte@openssl.org>