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
(Imported from upstream's 85cfc188c06bd046420ae70dd6e302f9efe022a9 and
4c52816d35681c0533c25fdd3abb4b7c6962302d)
Change-Id: Ic901aea8ea6457df27dc542a11c30464561e322b
Reviewed-on: https://boringssl-review.googlesource.com/2783
Reviewed-by: David Benjamin <davidben@chromium.org>
Reviewed-by: Adam Langley <agl@google.com>
Thanks to Denis Denisov for running the analysis.
Change-Id: I80810261e013423e746fd8d8afefb3581cffccc0
Reviewed-on: https://boringssl-review.googlesource.com/1701
Reviewed-by: Adam Langley <agl@google.com>
Where possible, functions should return one for success and zero for
error. The use of additional negative values to indicate an error is,
itself, error prone.
This change fixes many EVP functions to remove the possibility of
negative return values. Existing code that is testing for <= 0 will
continue to function, although there is the possibility that some code
was differentiating between negative values (error) and zero (invalid
signature) for the verify functions and will now show the wrong error
message.
Change-Id: I982512596bb18a82df65861394dbd7487783bd3d
Reviewed-on: https://boringssl-review.googlesource.com/1333
Reviewed-by: Adam Langley <agl@google.com>
Initial fork from f2d678e6e89b6508147086610e985d4e8416e867 (1.0.2 beta).
(This change contains substantial changes from the original and
effectively starts a new history.)
