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Vulnerability of Linux kernel: denial of service on MIPS

Synthesis of the vulnerability 

On a MIPS 64 bit processor, a local attacker can stop the system.
Impacted products: Debian, Fedora, Linux.
Severity of this bulletin: 1/4.
Creation date: 24/12/2008.
Références of this threat: CVE-2008-5701, DSA-1787-1, DSA-1794-1, FEDORA-2009-0816, FEDORA-2009-0923, VIGILANCE-VUL-8355.

Description of the vulnerability 

Linux system calls on a MIPS processor are located at different offsets:
 - 32 bit : at offset 4000 (__NR_O32_Linux)
 - 64 bit : at offset 5000 (__NR_Linux)
There is no system call with an offset less than 4000.

However, the arch/mips/kernel/scall64-o32.S file which implements 32 bit system calls on 64 bit processors always subtract 4000, even if the offset is inferior to 4000. The kernel thus reads at a high/negative memory address, which creates a fatal error.

On a MIPS 64 bit processor, a local attacker can therefore stop the system.
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This cybersecurity announce impacts software or systems such as Debian, Fedora, Linux.

Our Vigil@nce team determined that the severity of this threat alert is low.

The trust level is of type confirmed by the editor, with an origin of user shell.

An attacker with a expert ability can exploit this computer weakness alert.

Solutions for this threat 

Linux kernel: version 2.6.28.
Version 2.6.28 is corrected:
  http://www.kernel.org/pub/linux/kernel/v2.6/

Linux kernel: patch for MIPS.
A patch is available in information sources.

Debian 4: new linux-2.6.24 packages.
New packages are available:
  http://security.debian.org/pool/updates/main/l/linux-2.6.24/linux-*-2.6.24_2.6.24-6~etchnhalf.8etch1_*.deb

Debian 4: new linux-2.6 packages.
New packages are available:
  http://security.debian.org/pool/updates/main/l/linux-2.6/*_2.6.18.dfsg.1-24etch1_*.deb

Fedora: new kernel packages (27/01/2009).
New packages are available:
  kernel-2.6.27.12-78.2.8.fc9
  kernel-2.6.27.12-170.2.5.fc10
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