In the BN_hex2bn function the number of hex digits is calculated using
an int value |i|. Later |bn_expand| is called with a value of |i * 4|.
For large values of |i| this can result in |bn_expand| not allocating any
memory because |i * 4| is negative. This leaves ret->d as NULL leading
to a subsequent NULL ptr deref. For very large values of |i|, the
calculation |i * 4| could be a positive value smaller than |i|. In this
case memory is allocated to ret->d, but it is insufficiently sized
leading to heap corruption. A similar issue exists in BN_dec2bn.

This could have security consequences if BN_hex2bn/BN_dec2bn is ever
called by user applications with very large untrusted hex/dec data. This is
anticipated to be a rare occurrence.

All OpenSSL internal usage of this function uses data that is not expected
to be untrusted, e.g. config file data or application command line
arguments. If user developed applications generate config file data based
on untrusted data then it is possible that this could also lead to security
consequences. This is also anticipated to be a rare.

Issue reported by Guido Vranken.

CVE-2016-0797
Reviewed-by: NAndy Polyakov <appro@openssl.org>

Reviewed-by: NEmilia Käsper <emilia@openssl.org>

If the tests fail early before an ASYNC_WAIT_CTX is created then there
can be a use before init problem in asynctest.
Reviewed-by: NRichard Levitte <levitte@openssl.org>

Clarify that the "cleanup" routing does not get called if you invoke
ASYNC_WAIT_CTX_clear_fd() directly.
Reviewed-by: NRichard Levitte <levitte@openssl.org>

Implementation experience has shown that the original plan for async wait
fds was too simplistic. Originally the async logic created a pipe internally
and user/engine code could then get access to it via API calls. It is more
flexible if the engine is able to create its own fd and provide it to the
async code.

Another issue is that there can be a lot of churn in the fd value within
the context of (say) a single SSL connection leading to continually adding
and removing fds from (say) epoll. It is better if we can provide some
stability of the fd value across a whole SSL connection. This is
problematic because an engine has no concept of an SSL connection.

This commit refactors things to introduce an ASYNC_WAIT_CTX which acts as a
proxy for an SSL connection down at the engine layer.
Reviewed-by: NRichard Levitte <levitte@openssl.org>

VisualStudio 2015 has a bug where an internal compiler error was occurring.
By reordering the DEFINE_STACK_OF declarations for SSL_CIPHER and SSL_COMP
until after the ssl3.h include everything seems ok again.
Reviewed-by: NViktor Dukhovni <viktor@openssl.org>

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

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

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

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

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

Fix "mixed declarations and code" warnings.
Use OpenSSL headers.
Reviewed-by: NRich Salz <rsalz@openssl.org>
Reviewed-by: NEmilia Käsper <emilia@openssl.org>

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

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

Add X25519 to TLS supported curve list.
Reject attempts to configure keys which cannot be used
for signing.
Reviewed-by: NRich Salz <rsalz@openssl.org>
Reviewed-by: NEmilia Käsper <emilia@openssl.org>

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

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

Check sign/verify blocked with X25519
Reviewed-by: NRich Salz <rsalz@openssl.org>
Reviewed-by: NEmilia Käsper <emilia@openssl.org>

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

Add a flag to EC_METHOD for curves which do not support signing.
New function EC_KEY_can_sign() returns 1 is key can be used for signing.
Return an explicit error is an attempt is made to sign with
no signing curves.
Reviewed-by: NRich Salz <rsalz@openssl.org>
Reviewed-by: NEmilia Käsper <emilia@openssl.org>

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

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

In some cases the EC_POINT and EC_KEY BIGNUM components are suboptimal
or inappropriate. Add an "custom_data" field which curves can populate with
a custom structure to suit their needs.
Reviewed-by: NRich Salz <rsalz@openssl.org>
Reviewed-by: NEmilia Käsper <emilia@openssl.org>

Extract compression form in EC_KEY_oct2key() instead of manually in the
ASN.1 code. For custom curves do not assume the initial octet is the
compression form: it isn't for X25519 et al.
Reviewed-by: NRich Salz <rsalz@openssl.org>
Reviewed-by: NEmilia Käsper <emilia@openssl.org>

Add support for optional overrides of various private key operations
in EC_METHOD.
Reviewed-by: NRich Salz <rsalz@openssl.org>
Reviewed-by: NEmilia Käsper <emilia@openssl.org>

Extend EC_METHOD to permit additional customisation of private key and
ECDH operations.
Reviewed-by: NRich Salz <rsalz@openssl.org>
Reviewed-by: NEmilia Käsper <emilia@openssl.org>

Use standard X25519 and X448 names for OIDs. Delete EdDSA OIDs: for now they
wont be used and EdDSA may use a different format.
Reviewed-by: NRich Salz <rsalz@openssl.org>
Reviewed-by: NEmilia Käsper <emilia@openssl.org>

Signed-off-by: NRich Salz <rsalz@openssl.org>
Reviewed-by: NRichard Levitte <levitte@openssl.org>

Removing certs broke the mk1mf build.
Reviewed-by: NRichard Levitte <levitte@openssl.org>

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

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

Exiting out of a recipe more than necessary leaves an ugly message.
Reviewed-by: NRich Salz <rsalz@openssl.org>

When building with GNU C, clang or VMS C, it's more efficient to
generate dependency file and object file in one call rather than two.
Have the dependency output in a temporary file and compare it with the
previous one if available to see if replacement is waranted, thereby
avoiding unnecessary reconstruction of Makefile / descrip.mms.

Github issue #750
Reviewed-by: NRich Salz <rsalz@openssl.org>

Stack Overflow has a number of questions related to mutual authentication,
the client and its certificate. Those visiting the man pages for functions
like SSL_CTX_use_certificate and SSL_CTX_load_verify_locations don't
receive the benefit of a cross reference to SSL_CTX_set_client_CA_list.
Reviewed-by: NRichard Levitte <levitte@openssl.org>

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

- srtp_profiles variable is defined when building with SRTP, keeping
the variable usage also under ifndef OPENSSL_NO_SRTP
- alpn help option was kept under ifndef OPENSSL_NO_SRTP
Reviewed-by: NKurt Roeckx <kurt@openssl.org>
Reviewed-by: NRich Salz <rsalz@openssl.org>

The INCLUDE statement can handle setting extra include directories for
individual object files, let's use it.
Reviewed-by: NAndy Polyakov <appro@openssl.org>

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

Even though AVX support was added in GAS 2.19 vpclmulqdq was apparently
added in 2.20.
Reviewed-by: NRich Salz <rsalz@openssl.org>

RT#4323
Reviewed-by: NRich Salz <rsalz@openssl.org>