Red Hat Bugzilla – Bug 834618
CVE-2012-5536 pam_ssh_agent_auth: symbol crash leading to glibc error() called incorrectly
Last modified: 2013-02-21 23:40:28 EST
A symbol clash issue was found in the pam_ssh_agent_auth PAM module as shipped with Red Hat Enterprise Linux 6 and Fedora. In case of certain errors, pam_ssh_agent_auth calls error() function to report problems. Due to the way pam_ssh_agent_auth was built in Red Hat Enterprise Linux and Fedora packages, this led to glibc's error() function being called instead of the error() function from OpenSSH sources that was meant to be used. As the two error functions expect different arguments, this could cause an application configured to use the pam_ssh_agent_auth module (typically su or sudo) to crash, disclose portion of its memory, or, possibly, execute arbitrary code.
This issue did not affect upstream versions of pam_ssh_agent_auth and was specific to Red Hat Enterprise Linux / Fedora packages, where pam_ssh_agent_auth is part of the openssh source RPM. This bundling is used to avoid duplicating OpenSSH source code. pam_ssh_agent_auth embeds a copy of the OpenSSH code. It is not used in Red Hat Enterprise Linux / Fedora packages, instead OpenSSH code from the OpenSSH build is used. This flaw was consequence of this way the PAM module is built.
Fixed in Fedora Rawhide via:
This issue has been addressed in following products:
Red Hat Enterprise Linux 6
Via RHSA-2013:0519 https://rhn.redhat.com/errata/RHSA-2013-0519.html
This issue does not affect the version of openssh as shipped with Red Hat Enterprise Linux 5. This issue was addressed in Red Hat Enterprise Linux 6 via RHSA-2013:0519.