USN-95-1: Linux kernel vulnerabilities

15 March 2005

linux-source-2.6.8.1 vulnerabilities

A security issue affects these releases of Ubuntu and its derivatives:

  • Ubuntu 4.10

Software Description

Details

A remote Denial of Service vulnerability was discovered in the Netfilter IP packet handler. This allowed a remote attacker to crash the machine by sending specially crafted IP packet fragments. (CAN-2005-0209)

The Netfilter code also contained a memory leak. Certain locally generated packet fragments are reassembled twice, which caused a double allocation of a data structure. This could be locally exploited to crash the machine due to kernel memory exhaustion. (CAN-2005-0210)

Ben Martel and Stephen Blackheath found a remote Denial of Service vulnerability in the PPP driver. This allowed a malicious pppd client to crash the server machine. (CAN-2005-0384)

Georgi Guninski discovered a buffer overflow in the ATM driver. The atm_get_addr() function does not validate its arguments sufficiently, which could allow a local attacker to overwrite large portions of kernel memory by supplying a negative length argument. This could eventually lead to arbitrary code execution. (CAN-2005-0531)

Georgi Guninski also discovered three other integer comparison problems in the TTY layer, in the /proc interface and the ReiserFS driver. However, the previous Ubuntu security update (kernel version 2.6.8.1-16.11) already contained a patch which checks the arguments to these functions at a higher level and thus prevents these flaws from being exploited. (CAN-2005-0529, CAN-2005-0530, CAN-2005-0532)

Georgi Guninski discovered an integer overflow in the sys_epoll_wait() function which allowed local users to overwrite the first few kB of physical memory. However, very few applications actually use this space (dosemu is a notable exception), but potentially this could lead to privilege escalation. (CAN-2005-0736)

Eric Anholt discovered a race condition in the Radeon DRI driver. In some cases this allowed a local user with DRI privileges on a Radeon card to execute arbitrary code with root privileges.

Finally this update fixes a regression in the NFS server driver which was introduced in the previous security update (kernel version 2.6.8.1-16.11). We apologize for the inconvenience. (https://bugzilla.ubuntulinux.org/show_bug.cgi?id=6749)

Update instructions

The problem can be corrected by updating your system to the following package versions:

Ubuntu 4.10
linux-image-2.6.8.1-5-386
linux-image-2.6.8.1-5-686
linux-image-2.6.8.1-5-686-smp
linux-image-2.6.8.1-5-amd64-generic
linux-image-2.6.8.1-5-amd64-k8
linux-image-2.6.8.1-5-amd64-k8-smp
linux-image-2.6.8.1-5-amd64-xeon
linux-image-2.6.8.1-5-k7
linux-image-2.6.8.1-5-k7-smp
linux-image-2.6.8.1-5-power3
linux-image-2.6.8.1-5-power3-smp
linux-image-2.6.8.1-5-power4
linux-image-2.6.8.1-5-power4-smp
linux-image-2.6.8.1-5-powerpc
linux-image-2.6.8.1-5-powerpc-smp
linux-patch-debian-2.6.8.1

To update your system, please follow these instructions: https://wiki.ubuntu.com/Security/Upgrades.

References