CVE-2012-2100 - Necrotic Jizzim

Description

The ext4_fill_flex_info function in fs/ext4/super.c in the Linux kernel before 3.2.2 on the x86 platform and unspecified other platforms allows user-assisted remote attackers to trigger inconsistent filesystem-groups data and possibly cause a denial of service via a malformed ext4 filesystem containing a super block with a large FLEX_BG group size (aka s_log_groups_per_flex value). NOTE: this vulnerability exists because of an incomplete fix for CVE-2009-4307.

Reference

http://git.kernel.org/?p=linux/kernel/git/torvalds/linux-2.6.git;a=commit;h=d50f2ab6f050311dbf7b8f5501b25f0bf64a439b http://www.openwall.com/lists/oss-security/2012/04/12/11 https://bugzilla.redhat.com/show_bug.cgi?id=809687 http://www.kernel.org/pub/linux/kernel/v3.x/ChangeLog-3.2.2 https://github.com/torvalds/linux/commit/d50f2ab6f050311dbf7b8f5501b25f0bf64a439b http://www.securityfocus.com/bid/53414 http://rhn.redhat.com/errata/RHSA-2012-1445.html http://rhn.redhat.com/errata/RHSA-2012-1580.html