Debian Security Advisory

DSA-466-1 linux-kernel-2.2.10-powerpc-apus -- failing function and TLB flush

Date Reported:
18 Mar 2004
Affected Packages:
kernel-source-2.2.10, kernel-image-2.2.10-powerpc-apus
Security database references:
In the Bugtraq database (at SecurityFocus): BugTraq ID 9686.
In Mitre's CVE dictionary: CVE-2004-0077.
CERT's vulnerabilities, advisories and incident notes: VU#981222.
More information:

Paul Starzetz and Wojciech Purczynski of discovered a critical security vulnerability in the memory management code of Linux inside the mremap(2) system call. Due to flushing the TLB (Translation Lookaside Buffer, an address cache) too early it is possible for an attacker to trigger a local root exploit.

The attack vectors for 2.4.x and 2.2.x kernels are exclusive for the respective kernel series, though. We formerly believed that the exploitable vulnerability in 2.4.x does not exist in 2.2.x which is still true. However, it turned out that a second (sort of) vulnerability is indeed exploitable in 2.2.x, but not in 2.4.x, with a different exploit, of course.

For the stable distribution (woody) this problem has been fixed in version 2.2.10-13woody1 of 2.2 kernel images for the powerpc/apus architecture and in version 2.2.10-2 of Linux 2.2.10 source.

For the unstable distribution (sid) this problem will be fixed soon with the 2.4.20 kernel-image package for powerpc/apus. The old 2.2.10 kernel image will be removed from Debian unstable.

You are strongly advised to switch to the fixed 2.4.17 kernel-image package for powerpc/apus from woody until the 2.4.20 kernel-image package is fixed in the unstable distribution.

We recommend that you upgrade your Linux kernel package.

Vulnerability matrix for CAN-2004-0077

Fixed in:

Debian GNU/Linux 3.0 (woody)

Architecture-independent component:

MD5 checksums of the listed files are available in the original advisory.