By using non-DER or invalid encodings outside the signed portion of a
certificate the fingerprint can be changed without breaking the signature.
Although no details of the signed portion of the certificate can be changed
this can cause problems with some applications: e.g. those using the
certificate fingerprint for blacklists.
1. Reject signatures with non zero unused bits.
If the BIT STRING containing the signature has non zero unused bits reject
the signature. All current signature algorithms require zero unused bits.
2. Check certificate algorithm consistency.
Check the AlgorithmIdentifier inside TBS matches the one in the
certificate signature. NB: this will result in signature failure
errors for some broken certificates.
3. Check DSA/ECDSA signatures use DER.
Reencode DSA/ECDSA signatures and compare with the original received
signature. Return an error if there is a mismatch.
This will reject various cases including garbage after signature
(thanks to Antti Karjalainen and Tuomo Untinen from the Codenomicon CROSS
program for discovering this case) and use of BER or invalid ASN.1 INTEGERs
(negative or with leading zeroes).
CVE-2014-8275
Reviewed-by: Emilia Käsper <emilia@openssl.org>
(cherry picked from commit 208a6012be)
Conflicts:
crypto/dsa/dsa_vrf.c
Submitted by: "Andrzej Chmielowiec" <achmielowiec@enigma.com.pl>, steve@openssl.org
Approved by: steve@openssl.org
Truncate hash if it is too large: as required by FIPS 186-3.
- hide the EC_KEY structure definition in ec_lcl.c + add
some functions to use/access the EC_KEY fields
- change the way how method specific data (ecdsa/ecdh) is
attached to a EC_KEY
- add ECDSA_sign_ex and ECDSA_do_sign_ex functions with
additional parameters for pre-computed values
- rebuild libeay.num from 0.9.7
during "make errors" and thus during "make update".
Fix lots of bugs that util/ck_errf.pl can detect automatically.
Various others of these are still left to fix; that's why
"make update" will complain loudly when run now.
dh.h, dsa.h, ec.h, ecdh.h, ecdsa.h, rsa.h), as the opaque bignum types are
already declared in ossl_typ.h. Add explicit includes for bn.h in those C
files that need access to structure internals or API functions+macros.
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.
