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)
Sanity check field lengths and sums to avoid potential overflows and reject
excessively large X509_NAME structures.
Issue reported by Guido Vranken.
Reviewed-by: Matt Caswell <matt@openssl.org>
(cherry picked from commit 9b08619cb4)
Conflicts:
crypto/x509/x509.h
crypto/x509/x509_err.c
Reject zero length buffers passed to X509_NAME_onelne().
Issue reported by Guido Vranken.
Reviewed-by: Matt Caswell <matt@openssl.org>
(cherry picked from commit b33d1141b6)
This adds an explicit limit to the size of an X509_NAME structure. Some
part of OpenSSL (e.g. TLS) already effectively limit the size due to
restrictions on certificate size.
Reviewed-by: Matt Caswell <matt@openssl.org>
(cherry picked from commit 295f3a2491)
The traditional private key encryption algorithm doesn't function
properly if the IV length of the cipher is zero. These ciphers
(e.g. ECB mode) are not suitable for private key encryption
anyway.
Reviewed-by: Emilia Käsper <emilia@openssl.org>
(cherry picked from commit d78df5dfd6)
The i2d_X509() function can return a negative value on error. Therefore
we should make sure we check it.
Issue reported by Yuan Jochen Kang.
Reviewed-by: Emilia Käsper <emilia@openssl.org>
(cherry picked from commit 446ba8de9a)
This causes a compilation failure when using --strict-warnings in 1.0.2
and 1.0.1
Reviewed-by: Viktor Dukhovni <viktor@openssl.org>
(cherry picked from commit 0ca67644dd)
If the ASN.1 BIO is presented with a large length field read it in
chunks of increasing size checking for EOF on each read. This prevents
small files allocating excessive amounts of data.
CVE-2016-2109
Thanks to Brian Carpenter for reporting this issue.
Reviewed-by: Viktor Dukhovni <viktor@openssl.org>
(cherry picked from commit c62981390d)
Free up parsed X509_NAME structure if the CertificateRequest message
contains excess data.
The security impact is considered insignificant. This is a client side
only leak and a large number of connections to malicious servers would
be needed to have a significant impact.
This was found by libFuzzer.
Reviewed-by: Emilia Käsper <emilia@openssl.org>
Reviewed-by: Stephen Henson <steve@openssl.org>
(cherry picked from commit ec66c8c988)
no-comp on Windows was not actually suppressing compilation of the code,
although it was suppressing its use.
Reviewed-by: Richard Levitte <levitte@openssl.org>
(cherry picked from commit a6406c9598)
If a call to EVP_DecryptUpdate fails then a memory leak could occur.
Ensure that the memory is freed appropriately.
Issue reported by Guido Vranken.
Reviewed-by: Richard Levitte <levitte@openssl.org>
There is a potential double free in EVP_DigestInit_ex. This is believed
to be reached only as a result of programmer error - but we should fix it
anyway.
Issue reported by Guido Vranken.
Reviewed-by: Richard Levitte <levitte@openssl.org>
(cherry picked from commit ffe9150b15)
Some OSes, *cough*-dows, insist on stack being "wired" to
physical memory in strictly sequential manner, i.e. if stack
allocation spans two pages, then reference to farmost one can
be punishable by SEGV. But page walking can do good even on
other OSes, because it guarantees that villain thread hits
the guard page before it can make damage to innocent one...
Reviewed-by: Rich Salz <rsalz@openssl.org>
(cherry picked from commit adc4f1fc25)
Resolved conflicts:
crypto/bn/asm/x86_64-mont.pl
crypto/bn/asm/x86_64-mont5.pl
Reviewed-by: Richard Levitte <levitte@openssl.org>
PVK files with abnormally large length or salt fields can cause an
integer overflow which can result in an OOB read and heap corruption.
However this is an rarely used format and private key files do not
normally come from untrusted sources the security implications not
significant.
Fix by limiting PVK length field to 100K and salt to 10K: these should be
more than enough to cover any files encountered in practice.
Issue reported by Guido Vranken.
Reviewed-by: Rich Salz <rsalz@openssl.org>
(cherry picked from commit 5f57abe2b1)
Performance penalty varies from platform to platform, and even
key length. For rsa2048 sign it was observed to reach almost 10%.
CVE-2016-0702
Reviewed-by: Richard Levitte <levitte@openssl.org>
SSLv2 is by default disabled at build-time. Builds that are not
configured with "enable-ssl2" will not support SSLv2. Even if
"enable-ssl2" is used, users who want to negotiate SSLv2 via the
version-flexible SSLv23_method() will need to explicitly call either
of:
SSL_CTX_clear_options(ctx, SSL_OP_NO_SSLv2);
or
SSL_clear_options(ssl, SSL_OP_NO_SSLv2);
as appropriate. Even if either of those is used, or the application
explicitly uses the version-specific SSLv2_method() or its client
or server variants, SSLv2 ciphers vulnerable to exhaustive search
key recovery have been removed. Specifically, the SSLv2 40-bit
EXPORT ciphers, and SSLv2 56-bit DES are no longer available.
Mitigation for CVE-2016-0800
Reviewed-by: Emilia Käsper <emilia@openssl.org>
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: Andy Polyakov <appro@openssl.org>
(cherry picked from commit c175308407)
This reverts commit 23a58779f5.
This broke existing engines that didn't properly implement the sign and verify
functions.
Reviewed-by: Richard Levitte <levitte@openssl.org>
MR: #2077
The internal |fmtstr| function used in processing a "%s" format string
in the BIO_*printf functions could overflow while calculating the length
of a string and cause an OOB read when printing very long strings.
Additionally the internal |doapr_outch| function can attempt to write to
an OOB memory location (at an offset from the NULL pointer) in the event of
a memory allocation failure. In 1.0.2 and below this could be caused where
the size of a buffer to be allocated is greater than INT_MAX. E.g. this
could be in processing a very long "%s" format string. Memory leaks can also
occur.
These issues will only occur on certain platforms where sizeof(size_t) >
sizeof(int). E.g. many 64 bit systems. The first issue may mask the second
issue dependent on compiler behaviour.
These problems could enable attacks where large amounts of untrusted data
is passed to the BIO_*printf functions. If applications use these functions
in this way then they could be vulnerable. OpenSSL itself uses these
functions when printing out human-readable dumps of ASN.1 data. Therefore
applications that print this data could be vulnerable if the data is from
untrusted sources. OpenSSL command line applications could also be
vulnerable where they print out ASN.1 data, or if untrusted data is passed
as command line arguments.
Libssl is not considered directly vulnerable. Additionally certificates etc
received via remote connections via libssl are also unlikely to be able to
trigger these issues because of message size limits enforced within libssl.
CVE-2016-0799
Issue reported by Guido Vranken.
Reviewed-by: Andy Polyakov <appro@openssl.org>
(cherry picked from commit 578b956fe7)
The SRP user database lookup method SRP_VBASE_get_by_user had confusing
memory management semantics; the returned pointer was sometimes newly
allocated, and sometimes owned by the callee. The calling code has no
way of distinguishing these two cases.
Specifically, SRP servers that configure a secret seed to hide valid
login information are vulnerable to a memory leak: an attacker
connecting with an invalid username can cause a memory leak of around
300 bytes per connection.
Servers that do not configure SRP, or configure SRP but do not configure
a seed are not vulnerable.
In Apache, the seed directive is known as SSLSRPUnknownUserSeed.
To mitigate the memory leak, the seed handling in SRP_VBASE_get_by_user
is now disabled even if the user has configured a seed.
Applications are advised to migrate to SRP_VBASE_get1_by_user. However,
note that OpenSSL makes no strong guarantees about the
indistinguishability of valid and invalid logins. In particular,
computations are currently not carried out in constant time.
Reviewed-by: Rich Salz <rsalz@openssl.org>
Fix double free bug when parsing malformed DSA private keys.
Thanks to Adam Langley (Google/BoringSSL) for discovering this bug using
libFuzzer.
CVE-2016-0705
Reviewed-by: Emilia Käsper <emilia@openssl.org>
(cherry picked from commit 6c88c71b4e)
It's never problem if CRYPTO_ctr128_encrypt is called from EVP, because
buffer in question is always aligned within EVP_CIPHER_CTX structure.
RT#4218
Reviewed-by: Richard Levitte <levitte@openssl.org>
(cherry picked from commit 5e4bbeb49f)
Trouble is that LINK variable assignment in make-file interferes with
LINK environment variable, which can be used to modify Microsoft's
LINK.EXE behaviour.
RT#4289
Reviewed-by: Richard Levitte <levitte@openssl.org>
(cherry picked from commit d44bb1c31c)
Resolved conflicts:
util/pl/VC-32.pl
(cherry picked from commit 0fffd52242)
