The protocol selection code is now consolidated in a few consecutive
short functions in a single file and is table driven.  Protocol-specific
constraints that influence negotiation are moved into the flags
field of the method structure.  The same protocol version constraints
are now applied in all code paths.  It is now much easier to add
new protocol versions without reworking the protocol selection
logic.

In the presence of "holes" in the list of enabled client protocols
we no longer select client protocols below the hole based on a
subset of the constraints and then fail shortly after when it is
found that these don't meet the remaining constraints (suiteb, FIPS,
security level, ...).  Ideally, with the new min/max controls users
will be less likely to create "holes" in the first place.
Reviewed-by: NKurt Roeckx <kurt@openssl.org>

Reviewed-by: NViktor Dukhovni <viktor@openssl.org>

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

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

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

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

Suggested by David Benjamin
Reviewed-by: NRich Salz <rsalz@openssl.org>
Reviewed-by: NViktor Dukhovni <openssl-users@dukhovni.org>

MR: #1520

Remove all fixed DH ciphersuites and associated logic.
Reviewed-by: NMatt Caswell <matt@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>

Add new flag TLS1_FLAGS_RECEIVED_EXTMS which is set when the peer sends
the extended master secret extension.

Server now sends extms if and only if the client sent extms.

Check consistency of extms extension when resuming sessions following (where
practical) RFC7627.
Reviewed-by: NMatt Caswell <matt@openssl.org>

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

MR: #364

Reviewed-by: NDr. Stephen Henson <steve@openssl.org>

SSL_{CTX}_set_tmp_ecdh() allows to set 1 EC curve and then tries to use it.  On
the other hand SSL_{CTX_}set1_curves() allows you to set a list of curves, but
only when SSL_{CTX_}set_ecdh_auto() was called to turn it on.
Reviewed-by: NDr. Stephen Henson <steve@openssl.org>

This only gets used to set a specific curve without actually checking that the
peer supports it or not and can therefor result in handshake failures that can
be avoided by selecting a different cipher.
Reviewed-by: NDr. Stephen Henson <steve@openssl.org>

Don't hard code EVP_sha* etc for signature algorithms: use table
indices instead. Add SHA224 and SHA512 to tables.
Reviewed-by: NViktor Dukhovni <viktor@openssl.org>

Reviewed-by: NViktor Dukhovni <viktor@openssl.org>

Change handshake hash array into a single digest context simplifying the
handhake hash code. Use EVP_md5_sha1() if needed for handshake hashes in
TLS 1.1 and earlier.

Simplify PRF code to also use a single digest and treat EVP_md5_sha1()
as a special case.

Modify algorithm2 field of ciphers to use a single index value for handshake
hash and PRF instead of a bitmap.
Reviewed-by: NMatt Caswell <matt@openssl.org>

Reviewed-by: NAndy Polyakov <appro@openssl.org>

Reviewed-by: NTim Hudson <tjh@openssl.org>

This patch contains the necessary changes to provide GOST 2012
ciphersuites in TLS. It requires the use of an external GOST 2012 engine.
Reviewed-by: NMatt Caswell <matt@openssl.org>
Reviewed-by: NRich Salz <rsalz@openssl.org>

The following entry points have been made async aware:
SSL_accept
SSL_read
SSL_write

Also added is a new mode - SSL_MODE_ASYNC. Calling the above functions with
the async mode enabled will initiate a new async job. If an async pause is
encountered whilst executing the job (such as for example if using SHA1/RSA
with the Dummy Async engine), then the above functions return with
SSL_WANT_ASYNC. Calling the functions again (with exactly the same args
as per non-blocking IO), will resume the job where it left off.
Reviewed-by: NRich Salz <rsalz@openssl.org>

There are lots of calls to EVP functions from within libssl There were
various places where we should probably check the return value but don't.
This adds these checks.
Reviewed-by: NRichard Levitte <levitte@openssl.org>

This disables some ciphersuites which aren't supported in SSL v3:
specifically PSK ciphersuites which use SHA256 or SHA384 for the MAC.

Thanks to the Open Crypto Audit Project for identifying this issue.
Reviewed-by: NMatt Caswell <matt@openssl.org>

The new function SSL_use_certificate_chain_file was always crashing in
the internal function use_certificate_chain_file because it would pass a
NULL value for SSL_CTX *, but use_certificate_chain_file would
unconditionally try to dereference it.
Reviewed-by: NStephen Henson <steve@openssl.org>

Reviewed-by: NAndy Polyakov <appro@openssl.org>

Reviewed-by: NAndy Polyakov <appro@openssl.org>

There were a few remaining references to SSLv2 support which are no longer
relevant now that it has been removed.
Reviewed-by: NRich Salz <rsalz@openssl.org>
Reviewed-by: NRichard Levitte <levitte@openssl.org>

The function dtls1_link_min_mtu() was only used within d1_lib.c so make
it static.
Reviewed-by: NTim Hudson <tjh@openssl.org>
Reviewed-by: NRichard Levitte <levitte@openssl.org>

The SSL variable |in_handshake| seems misplaced. It would be better to have
it in the STATEM structure.
Reviewed-by: NTim Hudson <tjh@openssl.org>
Reviewed-by: NRichard Levitte <levitte@openssl.org>

Add an OSSL_ prefix onto STATEM
Reviewed-by: NTim Hudson <tjh@openssl.org>
Reviewed-by: NRichard Levitte <levitte@openssl.org>

The |no_cert_verify| should be in the state machine structure not in SSL
Reviewed-by: NTim Hudson <tjh@openssl.org>
Reviewed-by: NRichard Levitte <levitte@openssl.org>

The next_state variable is no longer needed in the new state machine.
Reviewed-by: NTim Hudson <tjh@openssl.org>
Reviewed-by: NRichard Levitte <levitte@openssl.org>

Move some function definitions around within the state machine to make sure
they are in the correct files. Also create a statem_locl.h header for stuff
entirely local to the state machine code and move various definitions into
it.
Reviewed-by: NTim Hudson <tjh@openssl.org>
Reviewed-by: NRichard Levitte <levitte@openssl.org>

Pull out the state machine into a separate sub directory. Also moved some
functions which were nothing to do with the state machine but were in state
machine files. Pulled all the SSL_METHOD definitions into one place...most
of those files had very little left in them any more.
Reviewed-by: NTim Hudson <tjh@openssl.org>
Reviewed-by: NRichard Levitte <levitte@openssl.org>

ssl_get_message is no longer used so it should be removed from
ssl_method_st
Reviewed-by: NTim Hudson <tjh@openssl.org>
Reviewed-by: NRichard Levitte <levitte@openssl.org>

Previously each message specific process function would create its own
PACKET structure. Rather than duplicate all of this code lots of times we
should create it in the state machine itself.
Reviewed-by: NTim Hudson <tjh@openssl.org>
Reviewed-by: NRichard Levitte <levitte@openssl.org>

The SSL structure contained a "state" variable that kept track of the state
machine in the old code. The new state machine does not use this so it can
be removed.
Reviewed-by: NTim Hudson <tjh@openssl.org>
Reviewed-by: NRichard Levitte <levitte@openssl.org>