USN-1704-2: Linux kernel (Quantal HWE) regression
Ubuntu Security Notice USN-1704-2
1st February, 2013
linux-lts-quantal - Linux kernel hardware enablement from Quantal regression
A security issue affects these releases of Ubuntu and its derivatives:
- Ubuntu 12.04 LTS
USN-1704-1 introduced a regression in the Linux kernel.
- linux-lts-quantal - Linux hardware enablement kernel from Quantal
USN-1704-1 fixed vulnerabilities in the Linux kernel. Due to an unrelated
regression inotify/fanotify stopped working after upgrading. This update
fixes the problem.
We apologize for the inconvenience.
Original advisory details:
Brad Spengler discovered a flaw in the Linux kernel's uname system call. An
unprivileged user could exploit this flaw to read kernel stack memory.
Jon Howell reported a flaw in the Linux kernel's KVM (Kernel-based virtual
machine) subsystem's handling of the XSAVE feature. On hosts, using qemu
userspace, without the XSAVE feature an unprivileged local attacker could
exploit this flaw to crash the system. (CVE-2012-4461)
Dmitry Monakhov reported a race condition flaw the Linux ext4 filesystem
that can expose stale data. An unprivileged user could exploit this flaw to
cause an information leak. (CVE-2012-4508)
A flaw was discovered in the Linux kernel's handling of script execution
when module loading is enabled. A local attacker could exploit this flaw to
cause a leak of kernel stack contents. (CVE-2012-4530)
Rodrigo Freire discovered a flaw in the Linux kernel's TCP illinois
congestion control algorithm. A local attacker could use this to cause a
denial of service. (CVE-2012-4565)
A flaw was discovered in the Linux kernel's handling of new hot-plugged
memory. An unprivileged local user could exploit this flaw to cause a
denial of service by crashing the system. (CVE-2012-5517)
Florian Weimer discovered that hypervkvpd, which is distributed in the
Linux kernel, was not correctly validating source addresses of netlink
packets. An untrusted local user can cause a denial of service by causing
hypervkvpd to exit. (CVE-2012-5532)
The problem can be corrected by updating your system to the following package version:
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.