Date: Tue, 25 Nov 2014 14:42:33 +0100 From: Salvatore Bonaccorso <carnil@...ian.org> To: OSS Security Mailinglist <oss-security@...ts.openwall.com> Cc: CVE Assignments MITRE <cve-assign@...re.org> Subject: CVE Request: buffer overflow in ksba_oid_to_str in Libksba Hi Today a new upstream version for Libksba (1.3.2) was announced. The upstream advisory mention following impact: > Impact of the security bug > ========================== > > By using special crafted S/MIME messages or ECC based OpenPGP data, it > is possible to create a buffer overflow. The bug is not easy to exploit > because there only 80 possible values which can be used to overwrite > memory. However, a denial of service is possible and someone may come > up with other clever attacks. Thus this should be fix. > > Affected versions: All Libksba versions < 1.3.2 > > Background: Yesterday Hanno Böck found an invalid memory access in the > 2.1 branch of GnuPG by conveying a malformed OID as part of an ECC key. > It turned out that this bug has also been in libksba ever since and > affects at least gpgsm and dirmngr. The code to convert an OID to its > string representation has an obvious error of not considering an invalid > encoding for arc-2. A first byte of 0x80 can be used to make a value of > less then 80 and we then subtract 80 from it as required by the OID > encoding rules. Due to the use of an unsigned integer this results in a > pretty long value which won't fit anymore into the allocated buffer. > The actual fix for lib Libksba is commit f715b9e. Announce: http://lists.gnupg.org/pipermail/gnupg-announce/2014q4/000359.html Upstream fix: http://git.gnupg.org/cgi-bin/gitweb.cgi?p=libksba.git;a=commit;h=f715b9e156dfa99ae829fc694e5a0abd23ef97d7 Can a CVE be assigned for this issue in libksba (if not already requested). Regards, Salvatore
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