Update tls_choose_sigalg to choose a signature algorithm for all
versions of TLS not just 1.3.

For TLS 1.2 we choose the highest preference signature algorithm
for the chosen ciphersuite.

For TLS 1.1 and earlier the signature algorithm is determined by
the ciphersuite alone. For RSA we use a special MD5+SHA1 signature
algorithm.
Reviewed-by: NRich Salz <rsalz@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/2623)

Reviewed-by: NRich Salz <rsalz@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/2623)

Add inline function ssl_has_cert which checks to see if a certificate and
private key for a given index are not NULL.
Reviewed-by: NRich Salz <rsalz@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/2623)

For converting the 2 byte group id into an unsigned int.
Reviewed-by: NRichard Levitte <levitte@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/2341)

Reviewed-by: NRichard Levitte <levitte@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/2341)

The original intent of SSL_PKEY_RSA_SIGN and SSL_PKEY_RSA_ENC was to
support two different keys for RSA signing and decrypt. However this
was never implemented and we only ever set one key and the other was
always NULL. Replace with single SSL_PKEY_RSA type.
Reviewed-by: NMatt Caswell <matt@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/2587)

Add SSL_kANY and SSL_aANY contants for TLS 1.3 ciphersuites. Return
appropriate text strings when they are used.
Reviewed-by: NMatt Caswell <matt@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/2550)

New function tls_choose_sigalg(). This is a signature algorithm version
of ssl3_choose_cipher(): it picks and sets the appropriate signature
algorithm and certificate based on shared signature algorithms.
Reviewed-by: NRich Salz <rsalz@openssl.org>
Reviewed-by: NMatt Caswell <matt@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/2339)

Reviewed-by: NRichard Levitte <levitte@openssl.org>
Reviewed-by: NMatt Caswell <matt@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/2287)

session_ctx and initial_ctx are aliases of each other, and with the
opaque data structures, there's no need to keep both around. Since
there were more references of session_ctx, replace all instances of
initial_ctx with session_ctx.
Reviewed-by: NRichard Levitte <levitte@openssl.org>
Reviewed-by: NRich Salz <rsalz@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/2334)

Reviewed-by: NRich Salz <rsalz@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/2324)

Remove unnecessary lookup operations: use the indices and data in the
lookup table directly.
Reviewed-by: NRich Salz <rsalz@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/2324)

Reviewed-by: NRich Salz <rsalz@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/2324)

Reviewed-by: NRich Salz <rsalz@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/2324)

Since every supported signature algorithm is now an entry in the
SIGALG_LOOKUP table we can replace shared signature algortihms with
pointers to constant table entries.
Reviewed-by: NRichard Levitte <levitte@openssl.org>
Reviewed-by: NMatt Caswell <matt@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/2301)

Store peer signature type in s->s3->tmp.peer_sigtype and check it
to see if the peer used PSS.
Reviewed-by: NRichard Levitte <levitte@openssl.org>
Reviewed-by: NMatt Caswell <matt@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/2301)

Reviewed-by: NRichard Levitte <levitte@openssl.org>
Reviewed-by: NMatt Caswell <matt@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/2301)

Reviewed-by: NRich Salz <rsalz@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/2259)

The newly added SSL3_CK_CIPHERSUITE_FLAG shouldn't be in a public header
file
Reviewed-by: NRich Salz <rsalz@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/2259)

Reviewed-by: NRich Salz <rsalz@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/2259)

Changing the value of SSL_MAX_MASTER_KEY_LENGTH had some unexpected
side effects in the <=TLS1.2 code which apparently relies on this being
48 for interoperability. Therefore create a new define for the TLSv1.3
resumption master secret which can be up to 64 bytes.

Found through the boring test suite.
Reviewed-by: NRich Salz <rsalz@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/2259)

Remove "magic" return values and use an enum instead.
Reviewed-by: NRich Salz <rsalz@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/2259)

If we have deserialized the SSL_SESSION then in some circumstances the
session->cipher value is NULL. We were patching up in some places but not
in others. We should just do it as part of loading the SSL_SESSION.
Reviewed-by: NRich Salz <rsalz@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/2259)

psk_kex_mode stores the available modes - not the one which we selected.
Reviewed-by: NRich Salz <rsalz@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/2259)

Reviewed-by: NRich Salz <rsalz@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/2259)

Update SSL_SESSION to store the age_add and use it where needed.
Reviewed-by: NRich Salz <rsalz@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/2259)

Reviewed-by: NRich Salz <rsalz@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/2259)

This is required for the later addition of resumption support.
Reviewed-by: NRich Salz <rsalz@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/2259)

The record layer was making decisions that should really be left to the
state machine around unexpected handshake messages that are received after
the initial handshake (i.e. renegotiation related messages). This commit
removes that code from the record layer and updates the state machine
accordingly. This simplifies the state machine and paves the way for
handling other messages post-handshake such as the NewSessionTicket in
TLSv1.3.
Reviewed-by: NRich Salz <rsalz@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/2259)

Reviewed-by: NRich Salz <rsalz@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/2290)

Reviewed-by: NRich Salz <rsalz@openssl.org>
Reviewed-by: NMatt Caswell <matt@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/1618)

Reviewed-by: NRich Salz <rsalz@openssl.org>
Reviewed-by: NRichard Levitte <levitte@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/1646)

A guard was in the wrong place in the header file.
Reviewed-by: NRich Salz <rsalz@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/2212)

TLSv1.3 introduces PSS based sigalgs. Offering these in a TLSv1.3 client
implies that the client is prepared to accept these sigalgs even in
TLSv1.2.
Reviewed-by: NRich Salz <rsalz@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/2157)

Reviewed-by: NRich Salz <rsalz@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/2157)

A misreading of the TLS1.3 spec meant we were using the handshake hashes
up to and including the Client Finished to calculate the client
application traffic secret. We should be only use up until the Server
Finished.
Reviewed-by: NRich Salz <rsalz@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/2157)

The sigalgs work has made some old lookup tables and functions redundant
so remove them.
Reviewed-by: NRich Salz <rsalz@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/2157)

We had an extra layer of indirection in looking up hashes and sigs based
on sigalgs which is now no longer necessary. This removes it.
Reviewed-by: NRich Salz <rsalz@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/2157)

The extensions refactor made this function redundant so we can remove it.
Reviewed-by: NRich Salz <rsalz@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/2157)

In TLSv1.2 an individual sig alg is represented by 1 byte for the hash
and 1 byte for the signature. In TLSv1.3 each sig alg is represented by
two bytes, where the two bytes together represent a single hash and
signature combination. This converts the internal representation of sigalgs
to use a single int for the pair, rather than a pair of bytes.
Reviewed-by: NRich Salz <rsalz@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/2157)