Several security issues were fixed in the kernel.
A flaw was discovered in the Linux kernel’s macvtap device driver, which is used in KVM (Kernel-based Virtual Machine) to create a network bridge between host and guest. A privleged user in a guest could exploit this flaw to crash the host, if the vhost_net module is loaded with the experimental_zcopytx option enabled. (CVE-2012-2119)
10 August 2012
A security issue affects these releases of Ubuntu and its derivatives:
Several security issues were fixed in the kernel.
A flaw was discovered in the Linux kernel’s macvtap device driver, which is used in KVM (Kernel-based Virtual Machine) to create a network bridge between host and guest. A privleged user in a guest could exploit this flaw to crash the host, if the vhost_net module is loaded with the experimental_zcopytx option enabled. (CVE-2012-2119)
An error was discovered in the Linux kernel’s network TUN/TAP device implementation. A local user with access to the TUN/TAP interface (which is not available to unprivileged users until granted by a root user) could exploit this flaw to crash the system or potential gain administrative privileges. (CVE-2012-2136)
A flaw was found in how the Linux kernel’s KVM (Kernel-based Virtual Machine) subsystem handled MSI (Message Signaled Interrupts). A local unprivileged user could exploit this flaw to cause a denial of service or potentially elevate privileges. (CVE-2012-2137)
A flaw was found in the Linux kernel’s Reliable Datagram Sockets (RDS) protocol implementation. A local, unprivileged user could use this flaw to cause a denial of service. (CVE-2012-2372)
Ulrich Obergfell discovered an error in the Linux kernel’s memory management subsystem on 32 bit PAE systems with more than 4GB of memory installed. A local unprivileged user could exploit this flaw to crash the system. (CVE-2012-2373)
It was discovered that hypervkvpd, which is distributed in the Linux kernel, was not correctly validating the origin on Netlink messages. An untrusted local user can cause a denial of service of Linux guests in Hyper-V virtualization environments. (CVE-2012-2669)
Dan Rosenberg discovered flaws in the Linux kernel’s NCI (Near Field Communication Controller Interface). A remote attacker could exploit these flaws to crash the system or potentially execute privileged code. (CVE-2012-3364)
A flaw was discovered in the Linux kernel’s epoll system call. An unprivileged local user could use this flaw to crash the system. (CVE-2012-3375)
Some errors where discovered in the Linux kernel’s UDF file system, which is used to mount some CD-ROMs and DVDs. An unprivileged local user could use these flaws to crash the system. (CVE-2012-3400)
A flaw was discovered in the madvise feature of the Linux kernel’s memory subsystem. An unprivileged local use could exploit the flaw to cause a denial of service (crash the system). (CVE-2012-3511)
Denys Fedoryshchenko discovered a flaw in the Linux kernel’s TCP receive processing for IPv4. A remote attacker could exploit this flaw to cause a denial of service (kernel resource consumption) via a flood of SYN+FIN TCP packets. (CVE-2012-6638)
The problem can be corrected by updating your system to the following package versions:
To update your system, please follow these instructions: https://wiki.ubuntu.com/Security/Upgrades.
After a standard system update you need to reboot your computer to make all the necessary changes.
ATTENTION: Due to an unavoidable ABI change the kernel updates have been given a new version number, which requires you to recompile and reinstall all third party kernel modules you might have installed. If you use linux-restricted-modules, you have to update that package as well to get modules which work with the new kernel version. Unless you manually uninstalled the standard kernel metapackages (e.g. linux-generic, linux-server, linux-powerpc), a standard system upgrade will automatically perform this as well.
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