This flag was not set anywhere within the codebase (only read). It could
only be set by an app reaching directly into s->s3->flags and setting it
directly. However that method became impossible when libssl was opaquified.

Even in 1.0.2/1.0.1 if an app set the flag directly it is only relevant to
ssl3_connect(), which calls SSL_clear() during initialisation that clears
any flag settings. Therefore it could take effect if the app set the flag
after the handshake has started but before it completed. It seems quite
unlikely that any apps really do this (especially as it is completely
undocumented).

The purpose of the flag is suppress flushing of the write bio on the client
side at the end of the handshake after the client has written the Finished
message whilst resuming a session. This enables the client to send
application data as part of the same flight as the Finished message.

This flag also controls the setting of a second flag SSL3_FLAGS_POP_BUFFER.
There is an interesting comment in the code about this second flag in the
implementation of ssl3_write:

	/* This is an experimental flag that sends the
	 * last handshake message in the same packet as the first
	 * use data - used to see if it helps the TCP protocol during
	 * session-id reuse */

It seems the experiment did not work because as far as I can tell nothing
is using this code. The above comment has been in the code since SSLeay.

This commit removes support for SSL3_FLAGS_DELAY_CLIENT_FINISHED, as well
as the associated SSL3_FLAGS_POP_BUFFER.
Reviewed-by: NRich Salz <rsalz@openssl.org>

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

The PSK identity hint should be stored in the SSL_SESSION structure
and not in the parent context (which will overwrite values used
by other SSL structures with the same SSL_CTX).
Reviewed-by: NMatt Caswell <matt@openssl.org>

Rewrite ssl3_digest_cached_records handling. Only digest cached records
if digest array is NULL: this means it is safe to call
ssl3_digest_cached_records multiple times (subsequent calls are no op).

Remove flag TLS1_FLAGS_KEEP_HANDSHAKE instead only update handshake buffer
if digest array is NULL.

Add additional "keep" parameter to ssl3_digest_cached_records to indicate
if the handshake buffer should be retained after digesting cached records
(needed for TLS 1.2 client authentication).
Reviewed-by: NMatt Caswell <matt@openssl.org>

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

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

If RSA or DSA is disabled we will never use a ciphersuite with
RSA/DSA authentication as it is already filtered out by the cipher
list logic.
Reviewed-by: NRichard Levitte <levitte@openssl.org>

As numerous comments indicate the certificate and key array is not an
appopriate structure to store the peers certificate: so remove it and
just the s->session->peer instead.
Reviewed-by: NRichard Levitte <levitte@openssl.org>

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

Reviewed-by: NMatt Caswell <matt@openssl.org>
MR #588

Reviewed-by: NMatt Caswell <matt@openssl.org>
MR #588

Remove a comment that suggested further clean up was required.
DH_free() performs the necessary cleanup.

With thanks to the Open Crypto Audit Project for reporting this issue.
Reviewed-by: NRich Salz <rsalz@openssl.org>

The session object on the client side is initially created during
construction of the ClientHello. If the client is DTLS1.2 capable then it
will store 1.2 as the version for the session. However if the server is only
DTLS1.0 capable then when the ServerHello comes back the client switches to
using DTLS1.0 from then on. However the session version does not get
updated. Therefore when the client attempts to resume that session the
server throws an alert because of an incorrect protocol version.
Reviewed-by: NTim Hudson <tjh@openssl.org>

If a NewSessionTicket is received by a multi-threaded client when
attempting to reuse a previous ticket then a race condition can occur
potentially leading to a double free of the ticket data.

CVE-2015-1791

This also fixes RT#3808 where a session ID is changed for a session already
in the client session cache. Since the session ID is the key to the cache
this breaks the cache access.

Parts of this patch were inspired by this Akamai change:
https://github.com/akamai/openssl/commit/c0bf69a791239ceec64509f9f19fcafb2461b0d3Reviewed-by: NRich Salz <rsalz@openssl.org>

Version negotiation was broken (one of the late changes in the review
process broke it). The problem is that TLS clients do not set first_packet,
whereas TLS/DTLS servers and DTLS clients do. The simple fix is to set
first_packet for TLS clients too.
Reviewed-by: NKurt Roeckx <kurt@openssl.org>

Given the pervasive nature of TLS extensions it is inadvisable to run
OpenSSL without support for them. It also means that maintaining
the OPENSSL_NO_TLSEXT option within the code is very invasive (and probably
not well tested). Therefore it is being removed.
Reviewed-by: NRich Salz <rsalz@openssl.org>
Reviewed-by: NRichard Levitte <levitte@openssl.org>

40 bit ciphers are limited to 512 bit RSA, 56 bit ciphers to 1024 bit.
Reviewed-by: NRich Salz <rsalz@openssl.org>

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

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

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

Move per-connection state out of the CERT structure: which should just be
for shared configuration data (e.g. certificates to use).

In particular move temporary premaster secret, raw ciphers, peer signature
algorithms and shared signature algorithms.
Reviewed-by: NRich Salz <rsalz@openssl.org>

Move these functions into t1_clnt.c, t1_srvr.c and t1_meth.c and take
advantage of the existing tls1_get*_method() functions that all the other
methods are using. Since these now have to support SSLv3 anyway we might
as well use the same set of get functions for both TLS and SSLv3.
Reviewed-by: NKurt Roeckx <kurt@openssl.org>

Miscellaneous updates following review comments on the version negotiation
rewrite patches.
Reviewed-by: NKurt Roeckx <kurt@openssl.org>

Continuing from the previous commit this changes the way we do client side
version negotiation. Similarly all of the s23* "up front" state machine code
has been avoided and again things now work much the same way as they already
did for DTLS, i.e. we just do most of the work in the
ssl3_get_server_hello() function.
Reviewed-by: NKurt Roeckx <kurt@openssl.org>

Remove RFC2712 Kerberos support from libssl. This code and the associated
standard is no longer considered fit-for-purpose.
Reviewed-by: NRich Salz <rsalz@openssl.org>

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

If server requests a certificate, but the client doesn't send one, cache
digested records. This is an optimisation and ensures the correct finished
mac is used when extended master secret is used with client authentication.
Reviewed-by: NTim Hudson <tjh@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>

Ensure all fatal errors transition into the new error state on the client
side.
Reviewed-by: NRich Salz <rsalz@openssl.org>

After the finale, the "real" final part. :)  Do a recursive grep with
"-B1 -w [a-zA-Z0-9_]*_free" to see if any of the preceeding lines are
an "if NULL" check that can be removed.
Reviewed-by: NTim Hudson <tjh@openssl.org>

There were a dozen-plus instances of this construct:
   if (0) { label: ..... }
Reviewed-by: NTim Hudson <tjh@openssl.org>

Don't check for NULL before calling OPENSSL_free
Reviewed-by: NRichard Levitte <levitte@openssl.org>

Add OPENSSL_clear_free which merges cleanse and free.
(Names was picked to be similar to BN_clear_free, etc.)
Removed OPENSSL_freeFunc macro.
Fixed the small simple ones that are left:
        CRYPTO_free CRYPTO_free_locked OPENSSL_free_locked
Reviewed-by: NRichard Levitte <levitte@openssl.org>

Don't check for NULL before calling a free routine.  This gets X509_.*free:
    x509_name_ex_free X509_policy_tree_free X509_VERIFY_PARAM_free
    X509_STORE_free X509_STORE_CTX_free X509_PKEY_free
    X509_OBJECT_free_contents X509_LOOKUP_free X509_INFO_free
Reviewed-by: NRichard Levitte <levitte@openssl.org>

EAP-FAST session resumption relies on handshake message lookahead
to determine server intentions. Commits
980bc1ec
and
7b3ba508
removed the lookahead so broke session resumption.

This change partially reverts the commits and brings the lookahead back
in reduced capacity for TLS + EAP-FAST only. Since EAP-FAST does not
support regular session tickets, the lookahead now only checks for a
Finished message.

Regular handshakes are unaffected by this change.
Reviewed-by: NDavid Benjamin <davidben@chromium.org>
Reviewed-by: NMatt Caswell <matt@openssl.org>

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

Avoid checking for NULL before calling free functions.  This gets
ssl.*free:
    ssl_sess_cert_free ssl_free ssl_excert_free ssl_cert_free
    SSL_free SSL_SRP_CTX_free SSL_SESSION_free SSL_CTX_free
    SSL_CTX_SRP_CTX_free SSL_CONF_CTX_free
Reviewed-by: NKurt Roeckx <kurt@openssl.org>

This gets EC_GROUP_clear_free EC_GROUP_free, EC_KEY_free,
EC_POINT_clear_free, EC_POINT_free
Reviewed-by: NKurt Roeckx <kurt@openssl.org>

Ensure RAND_bytes return value is checked correctly, and that we no longer
use RAND_pseudo_bytes.
Reviewed-by: NRichard Levitte <levitte@openssl.org>

Start ensuring all OpenSSL "free" routines allow NULL, and remove
any if check before calling them.
This gets DH_free, DSA_free, RSA_free
Reviewed-by: NMatt Caswell <matt@openssl.org>