fs/partitions/efi.c: corrupted GUID partition tables can cause kernel oops
authorTimo Warns <Warns@pre-sense.de>
Fri, 10 Jun 2011 10:05:59 +0000 (11:05 +0100)
committerAndy Whitcroft <apw@canonical.com>
Mon, 13 Jun 2011 07:47:22 +0000 (08:47 +0100)
commitbbfba6b73e68fe808be4707e827d5867a9dc6f2e
treea6ec37612773ddd8033c781567b5618db70c17e4
parent980ad74ba752126d0f3e9c4d00bbe7e70fa8bcc6
fs/partitions/efi.c: corrupted GUID partition tables can cause kernel oops

The kernel automatically evaluates partition tables of storage devices.
The code for evaluating GUID partitions (in fs/partitions/efi.c) contains
a bug that causes a kernel oops on certain corrupted GUID partition
tables.

This bug has security impacts, because it allows, for example, to
prepare a storage device that crashes a kernel subsystem upon connecting
the device (e.g., a "USB Stick of (Partial) Death").

crc = efi_crc32((const unsigned char *) (*gpt), le32_to_cpu((*gpt)->header_size));

computes a CRC32 checksum over gpt covering (*gpt)->header_size bytes.
There is no validation of (*gpt)->header_size before the efi_crc32 call.

A corrupted partition table may have large values for (*gpt)->header_size.
 In this case, the CRC32 computation access memory beyond the memory
allocated for gpt, which may cause a kernel heap overflow.

Validate value of GUID partition table header size.

[akpm@linux-foundation.org: fix layout and indenting]
Signed-off-by: Timo Warns <warns@pre-sense.de>
Cc: Matt Domsch <Matt_Domsch@dell.com>
Cc: Eugene Teo <eugeneteo@kernel.sg>
Cc: Dave Jones <davej@codemonkey.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
(cherry picked from commit 3eb8e74ec72736b9b9d728bad30484ec89c91dde)
CVE-2011-1577
BugLink: http://bugs.launchpad.net/bugs/795418
Acked-by: Stefan Bader <stefan.bader@canonical.com>
Acked-by: Seth Forshee <seth.forshee@canonical.com>
Signed-off-by: Andy Whitcroft <apw@canonical.com>
fs/partitions/efi.c