libtasn1, GNU TLS: Security flaw in DER decoding

Background

Libtasn1 is a library used to parse ASN.1 (Abstract Syntax Notation One) objects, and perform DER (Distinguished Encoding Rules) decoding. Libtasn1 is included with the GNU TLS library, which is used by applications to provide a cryptographically secure communications channel.

Description

Evgeny Legerov has reported a flaw in the DER decoding routines provided by libtasn1, which could cause an out of bounds access to occur.

Impact

A remote attacker could cause an application using libtasn1 to crash and potentially execute arbitrary code by sending specially crafted input.

Workaround

There is no known workaround at this time.

Resolution

All libtasn1 users should upgrade to the latest version:

 # emerge --sync
 # emerge --ask --oneshot --verbose ">=dev-libs/libtasn1-0.2.18"

All GNU TLS users should upgrade to the latest version:

 # emerge --sync
 # emerge --ask --oneshot --verbose ">=net-libs/gnutls-1.2.10"