Debian Security Advisory

DSA-1233-1 kernel-source-2.6.8 -- several vulnerabilities

Date Reported:
10 Dec 2006
Affected Packages:
Security database references:
In Mitre's CVE dictionary: CVE-2006-3741, CVE-2006-4538, CVE-2006-4813, CVE-2006-4997, CVE-2006-5871.
More information:

Several local and remote vulnerabilities have been discovered in the Linux kernel that may lead to a denial of service or the execution of arbitrary code. The Common Vulnerabilities and Exposures project identifies the following problems:

  • CVE-2006-3741

    Stephane Eranian discovered a local DoS (Denial of Service) vulnerability on the ia64 architecture. A local user could exhaust the available file descriptors by exploiting a counting error in the permonctl() system call.

  • CVE-2006-4538

    Kirill Korotaev reported a local DoS (Denial of Service) vulnerability on the ia64 and sparc architectures. A user could cause the system to crash by executing a malformed ELF binary due to insufficient verification of the memory layout.

  • CVE-2006-4813

    Dmitriy Monakhov reported a potential memory leak in the __block_prepare_write function. __block_prepare_write does not properly sanitize kernel buffers during error recovery, which could be exploited by local users to gain access to sensitive kernel memory.

  • CVE-2006-4997

    ADLab Venustech Info Ltd reported a potential remote DoS (Denial of Service) vulnerability in the IP over ATM subsystem. A remote system could cause the system to crash by sending specially crafted packets that would trigger an attempt to free an already-freed pointer resulting in a system crash.

  • CVE-2006-5174

    Martin Schwidefsky reported a potential leak of sensitive information on s390 systems. The copy_from_user function did not clear the remaining bytes of the kernel buffer after receiving a fault on the userspace address, resulting in a leak of uninitialized kernel memory. A local user could exploit this by appending to a file from a bad address.

  • CVE-2006-5619

    James Morris reported a potential local DoS (Denial of Service) vulnerability that could be used to hang or oops a system. The seqfile handling for /proc/net/ip6_flowlabel has a flaw that can be exploited to cause an infinite loop by reading this file after creating a flowlabel.

  • CVE-2006-5649

    Fabio Massimo Di Nitto reported a potential remote DoS (Denial of Service) vulnerability on powerpc systems. The alignment exception only checked the exception table for -EFAULT, not for other errors. This can be exploited by a local user to cause a system crash (panic).

  • CVE-2006-5751

    Eugene Teo reported a vulnerability in the get_fdb_entries function that could potentially be exploited to allow arbitrary code execution with escalated privileges.

  • CVE-2006-5871

    Bill Allombert reported that various mount options are ignored by smbfs when UNIX extensions are enabled. This includes the uid, gid and mode options. Client systems would silently use the server-provided settings instead of honoring these options, changing the security model. This update includes a fix from Haroldo Gamal that forces the kernel to honor these mount options. Note that, since the current versions of smbmount always pass values for these options to the kernel, it is not currently possible to activate unix extensions by omitting mount options. However, this behavior is currently consistent with the current behavior of the next Debian release, 'etch'.

The following matrix explains which kernel version for which architecture fix the problems mentioned above:

Debian 3.1 (sarge)
Source 2.6.8-16sarge6
Alpha architecture 2.6.8-16sarge6
AMD64 architecture 2.6.8-16sarge6
HP Precision architecture 2.6.8-6sarge6
Intel IA-32 architecture 2.6.8-16sarge6
Intel IA-64 architecture 2.6.8-14sarge6
Motorola 680x0 architecture 2.6.8-4sarge6
PowerPC architecture 2.6.8-12sarge6
IBM S/390 architecture 2.6.8-5sarge6
Sun Sparc architecture 2.6.8-15sarge6

The following matrix lists additional packages that were rebuilt for compatibility with or to take advantage of this update:

Debian 3.1 (sarge)
fai-kernels 1.9.1sarge5

We recommend that you upgrade your kernel package immediately and reboot the machine. If you have built a custom kernel from the kernel source package, you will need to rebuild to take advantage of these fixes.

Fixed in:

Debian GNU/Linux 3.1 (sarge)

Architecture-independent component:
Intel IA-32:
Intel IA-64:
Motorola 680x0:
IBM S/390:
Sun Sparc:

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