USN-95-1: Linux kernel vulnerabilities
15 March 2005
A security issue affects these releases of Ubuntu and its derivatives:
- Ubuntu 4.10
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 126.96.36.199-16.11) 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 188.8.131.52-16.11). We apologize for the inconvenience. (https://bugzilla.ubuntulinux.org/show_bug.cgi?id=6749)
The problem can be corrected by updating your system to the following package versions:
- Ubuntu 4.10
To update your system, please follow these instructions: https://wiki.ubuntu.com/Security/Upgrades.