Don't have #error statements in header files, but instead wrap
the contents of that file in #ifndef OPENSSL_NO_xxx
This means it is now always safe to include the header file.
Reviewed-by: NRichard Levitte <levitte@openssl.org>

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

Add utility macros REF_ASSERT_NOT and REF_PRINT_COUNT
This is also RT 4181
Reviewed-by: NRichard Levitte <levitte@openssl.org>

PACKET contents should be read-only. To achieve this, also
- constify two user callbacks
- constify BUF_reverse.
Reviewed-by: NRich Salz <rsalz@openssl.org>

This was done by the following
        find . -name '*.[ch]' | /tmp/pl
where /tmp/pl is the following three-line script:
        print unless $. == 1 && m@/\* .*\.[ch] \*/@;
        close ARGV if eof; # Close file to reset $.

And then some hand-editing of other files.
Reviewed-by: NViktor Dukhovni <viktor@openssl.org>

RT#4080
Reviewed-by: NRich Salz <rsalz@openssl.org>
Reviewed-by: NMatt Caswell <matt@openssl.org>

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

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

Rename BUF_{strdup,strlcat,strlcpy,memdup,strndup,strnlen}
to OPENSSL_{strdup,strlcat,strlcpy,memdup,strndup,strnlen}
Add #define's for the old names.
Add CRYPTO_{memdup,strndup}, called by OPENSSL_{memdup,strndup} macros.
Reviewed-by: NTim Hudson <tjh@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>

Add CRYPTO_free_ex_index (for shared libraries)
Unify and complete the documentation for all "ex_data" API's and objects.
Replace xxx_get_ex_new_index functions with a macro.
Added an exdata test.
Renamed the ex_data internal datatypes.
Reviewed-by: NMatt Caswell <matt@openssl.org>

And a scalar !x --> x==0 test
Reviewed-by: NKurt Roeckx <kurt@openssl.org>

if we have a malloc |x = OPENSSL_malloc(...)| sometimes we check |x|
for NULL and sometimes we treat it as a boolean |if(!x) ...|. Standardise
the approach in libssl.
Reviewed-by: NKurt Roeckx <kurt@openssl.org>

Note that this commit constifies a user callback parameter and therefore
will break compilation for applications using this callback. But unless
they are abusing write access to the buffer, the fix is trivial.
Reviewed-by: NAndy Polyakov <appro@openssl.org>

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

The user callback takes a non-const pointer, so don't pass PACKET data
to it directly; rather, grab a local copy.
Reviewed-by: NMatt Caswell <matt@openssl.org>

Move all packet parsing to the beginning of the method. This limits the
SSLv2 compatibility soup to the parsing, and makes the rest of the
processing uniform.

This is also needed for simpler EMS support: EMS servers need to do an
early scan for EMS to make resumption decisions. This'll be easier when
the entire ClientHello is parsed in the beginning.

As a side effect,
1) PACKETize ssl_get_prev_session and tls1_process_ticket; and
2) Delete dead code for SSL_OP_NETSCAPE_REUSE_CIPHER_CHANGE_BUG.
Reviewed-by: NMatt Caswell <matt@openssl.org>

After openssl_zalloc, cleanup more "set to 0/NULL" assignments.
Many are from github feedback.
Reviewed-by: NTim Hudson <tjh@openssl.org>

There are many places (nearly 50) where we malloc and then memset.
Add an OPENSSL_zalloc routine to encapsulate that.
(Missed one conversion; thanks Richard)
Also fixes GH328
Reviewed-by: NRichard Levitte <levitte@openssl.org>

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

Uses the new PACKET code to process the incoming ClientHello including all
extensions etc.
Reviewed-by: NTim Hudson <tjh@openssl.org>

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

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

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

Fix error handling in ssl_session_dup, as well as incorrect setting up of
the session ticket. Follow on from CVE-2015-1791.

Thanks to LibreSSL project for reporting these issues.
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>

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>

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>

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>

For a local variable:
        TYPE *p;
Allocations like this are "risky":
        p = OPENSSL_malloc(sizeof(TYPE));
if the type of p changes, and the malloc call isn't updated, you
could get memory corruption.  Instead do this:
        p = OPENSSL_malloc(sizeof(*p));
Also fixed a few memset() calls that I noticed while doing this.
Reviewed-by: NRichard Levitte <levitte@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>

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

Sanity check the |len| parameter to ensure it is positive. Thanks to Kevin
Wojtysiak (Int3 Solutions) and Paramjot Oberoi (Int3 Solutions) for
reporting this issue.
Reviewed-by: NAndy Polyakov <appro@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>

Following ANSI C rules, remove the casts from calls to
OPENSSL_malloc and OPENSSL_realloc.
Reviewed-by: NRichard Levitte <levitte@openssl.org>

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

If OpenSSL is configured with no-tlsext then ssl_get_prev_session can read
past the end of the ClientHello message if the session_id length in the
ClientHello is invalid. This should not cause any security issues since the
underlying buffer is 16k in size. It should never be possible to overrun by
that many bytes.

This is probably made redundant by the previous commit - but you can never be
too careful.

With thanks to Qinghao Tang for reporting this issue.
Reviewed-by: NRich Salz <rsalz@openssl.org>

Ongoing work to skip NULL check before calling free routine.  This gets:
    ecp_nistz256_pre_comp_free nistp224_pre_comp_free nistp256_pre_comp_free
    nistp521_pre_comp_free PKCS7_free PKCS7_RECIP_INFO_free
    PKCS7_SIGNER_INFO_free sk_PKCS7_pop_free PKCS8_PRIV_KEY_INFO_free
    PKCS12_free PKCS12_SAFEBAG_free PKCS12_free sk_PKCS12_SAFEBAG_pop_free
    SSL_CONF_CTX_free SSL_CTX_free SSL_SESSION_free SSL_free ssl_cert_free
    ssl_sess_cert_free
Reviewed-by: NKurt Roeckx <kurt@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>