An overflow can occur in the EVP_EncryptUpdate function. If an attacker is
able to supply very large amounts of input data after a previous call to
EVP_EncryptUpdate with a partial block then a length check can overflow
resulting in a heap corruption.
Following an analysis of all OpenSSL internal usage of the
EVP_EncryptUpdate function all usage is one of two forms.
The first form is like this:
EVP_EncryptInit()
EVP_EncryptUpdate()
i.e. where the EVP_EncryptUpdate() call is known to be the first called
function after an EVP_EncryptInit(), and therefore that specific call
must be safe.
The second form is where the length passed to EVP_EncryptUpdate() can be
seen from the code to be some small value and therefore there is no
possibility of an overflow.
Since all instances are one of these two forms, I believe that there can
be no overflows in internal code due to this problem.
It should be noted that EVP_DecryptUpdate() can call EVP_EncryptUpdate()
in certain code paths. Also EVP_CipherUpdate() is a synonym for
EVP_EncryptUpdate(). Therefore I have checked all instances of these
calls too, and came to the same conclusion, i.e. there are no instances
in internal usage where an overflow could occur.
This could still represent a security issue for end user code that calls
this function directly.
CVE-2016-2106
Issue reported by Guido Vranken.
Reviewed-by: Tim Hudson <tjh@openssl.org>
(cherry picked from commit 3f3582139f)
Causes more problems than it fixes: even though error codes
are not part of the stable API, several users rely on the
specific error code, and the change breaks them. Conversely,
we don't have any concrete use-cases for constant-time behaviour here.
This reverts commit 738911cde6.
Reviewed-by: Andy Polyakov <appro@openssl.org>
Do the final padding check in EVP_DecryptFinal_ex in constant time to
avoid a timing leak from padding failure.
Reviewed-by: Rich Salz <rsalz@openssl.org>
(cherry picked from commit 4aac102f75)
Conflicts:
crypto/evp/evp_enc.c
Add support for key wrap algorithms via EVP interface.
Generalise AES wrap algorithm and add to modes, making existing
AES wrap algorithm a special case.
Move test code to evptests.txt
(cherry picked from commit 97cf1f6c28)
Conflicts:
CHANGES
When in FIPS mode the approved implementations are used as normal,
when not in FIPS mode the internal unapproved versions are used instead.
This means that the FIPS capable OpenSSL isn't forced to use the
(often lower perfomance) FIPS implementations outside FIPS mode.
knock-on work than expected - they've been extracted into a patch
series that can be completed elsewhere, or in a different branch,
before merging back to HEAD.
changes are the fallout). As this could break source code that doesn't
directly include headers for interfaces it uses, changes to recursive
includes are covered by the OPENSSL_NO_DEPRECATED symbol. It's better to
define this when building and using openssl, and then adapt code where
necessary - this is how to stay current. However the mechanism exists for
the lethargic.
I have tried to convert 'len' type variable declarations to unsigned as a
means to address these warnings when appropriate, but when in doubt I have
used casts in the comparisons instead. The better solution (that would get
us all lynched by API users) would be to go through and convert all the
function prototypes and structure definitions to use unsigned variables
except when signed is necessary. The proliferation of (signed) "int" for
strictly non-negative uses is unfortunate.
not implemented. (Bug reported by Martin Szotkowski)
This also changes the non-"_ex" versions to defer directly to
EVP_CipherInit_ex() rather than EVP_CipherInit() to avoid an unecessary
level of indirection.
See crypto/engine/README for details.
- it also removes openbsd_hw.c from the build (that functionality is
going to be available in the openbsd ENGINE in a upcoming commit)
- evp_test has had the extra initialisation added so it will use (if
possible) any ENGINEs supporting the algorithms required.
