USN-395-1: Linux kernel vulnerabilities

14 December 2006

linux-source-2.6.12/-2.6.15/-2.6.17 vulnerabilities

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

  • Ubuntu 6.10
  • Ubuntu 6.06 LTS
  • Ubuntu 5.10

Software Description


Mark Dowd discovered that the netfilter iptables module did not correcly handle fragmented packets. By sending specially crafted packets, a remote attacker could exploit this to bypass firewall rules. This has only be fixed for Ubuntu 6.10; the corresponding fix for Ubuntu 5.10 and 6.06 will follow soon. (CVE-2006-4572)

Dmitriy Monakhov discovered an information leak in the __block_prepare_write() function. During error recovery, this function did not properly clear memory buffers which could allow local users to read portions of unlinked files. This only affects Ubuntu 5.10. (CVE-2006-4813)

ADLab Venustech Info Ltd discovered that the ATM network driver referenced an already released pointer in some circumstances. By sending specially crafted packets to a host over ATM, a remote attacker could exploit this to crash that host. This does not affect Ubuntu 6.10. (CVE-2006-4997)

Matthias Andree discovered that the NFS locking management daemon (lockd) did not correctly handle mixing of ‘lock’ and ‘nolock’ option mounts on the same client. A remote attacker could exploit this to crash lockd and thus rendering the NFS imports inaccessible. This only affects Ubuntu 5.10. (CVE-2006-5158)

The task switching code did not save and restore EFLAGS of processes. By starting a specially crafted executable, a local attacker could exploit this to eventually crash many other running processes. This does not affect Ubuntu 6.10. (CVE-2006-5173)

James Morris discovered that the ip6fl_get_n() function incorrectly handled flow labels. A local attacker could exploit this to crash the kernel. (CVE-2006-5619)

Fabio Massimo Di Nitto discovered that the sys_get_robust_list and sys_set_robust_list system calls lacked proper lock handling on the powerpc platform. A local attacker could exploit this to create unkillable processes, drain all available CPU/memory, and render the machine unrebootable. This only affects Ubuntu 6.10. (CVE-2006-5648)

Fabio Massimo Di Nitto discovered a flaw in the alignment check exception handling on the powerpc platform. A local attacker could exploit this to cause a kernel panic and crash the machine. (CVE-2006-5649)

Certain corrupted squashfs file system images caused a memory allocation to be freed twice. By mounting a specially crafted squashfs file system, a local attacker could exploit this to crash the kernel. This does not affect Ubuntu 5.10. (CVE-2006-5701)

An integer overflow was found in the get_fdb_entries() function of the network bridging code. By executing a specially crafted ioctl, a local attacker could exploit this to execute arbitrary code with root privileges. (CVE-2006-5751)

Update instructions

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

Ubuntu 6.10
linux-image-2.6.17-10-386 -
linux-image-2.6.17-10-generic -
linux-image-2.6.17-10-powerpc -
linux-image-2.6.17-10-powerpc-smp -
linux-image-2.6.17-10-powerpc64-smp -
linux-image-2.6.17-10-server -
linux-image-2.6.17-10-server-bigiron -
linux-image-2.6.17-10-sparc64 -
linux-image-2.6.17-10-sparc64-smp -
Ubuntu 6.06 LTS
linux-image-2.6.15-27-386 - 2.6.15-27.50
linux-image-2.6.15-27-686 - 2.6.15-27.50
linux-image-2.6.15-27-amd64-generic - 2.6.15-27.50
linux-image-2.6.15-27-amd64-k8 - 2.6.15-27.50
linux-image-2.6.15-27-amd64-server - 2.6.15-27.50
linux-image-2.6.15-27-amd64-xeon - 2.6.15-27.50
linux-image-2.6.15-27-k7 - 2.6.15-27.50
linux-image-2.6.15-27-powerpc - 2.6.15-27.50
linux-image-2.6.15-27-powerpc-smp - 2.6.15-27.50
linux-image-2.6.15-27-powerpc64-smp - 2.6.15-27.50
linux-image-2.6.15-27-server - 2.6.15-27.50
linux-image-2.6.15-27-server-bigiron - 2.6.15-27.50
linux-image-2.6.15-27-sparc64 - 2.6.15-27.50
linux-image-2.6.15-27-sparc64-smp - 2.6.15-27.50
linux-source-2.6.15 - 2.6.15-27.50
Ubuntu 5.10
linux-image-2.6.12-10-386 - 2.6.12-10.42
linux-image-2.6.12-10-686 - 2.6.12-10.42
linux-image-2.6.12-10-686-smp - 2.6.12-10.42
linux-image-2.6.12-10-amd64-generic - 2.6.12-10.42
linux-image-2.6.12-10-amd64-k8 - 2.6.12-10.42
linux-image-2.6.12-10-amd64-k8-smp - 2.6.12-10.42
linux-image-2.6.12-10-amd64-xeon - 2.6.12-10.42
linux-image-2.6.12-10-k7 - 2.6.12-10.42
linux-image-2.6.12-10-k7-smp - 2.6.12-10.42
linux-image-2.6.12-10-powerpc - 2.6.12-10.42
linux-image-2.6.12-10-powerpc-smp - 2.6.12-10.42
linux-image-2.6.12-10-powerpc64-smp - 2.6.12-10.42
linux-image-2.6.12-10-sparc64 - 2.6.12-10.42
linux-image-2.6.12-10-sparc64-smp - 2.6.12-10.42
linux-patch-ubuntu-2.6.12 - 2.6.12-10.42

To update your system, please follow these instructions:

After a standard system upgrade you need to reboot your computer to effect the necessary changes.