From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753542Ab1H0O4d (ORCPT ); Sat, 27 Aug 2011 10:56:33 -0400 Received: from cantor2.suse.de ([195.135.220.15]:46479 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752483Ab1H0O4a (ORCPT ); Sat, 27 Aug 2011 10:56:30 -0400 X-Mailbox-Line: From gregkh@clark.kroah.org Fri Aug 26 15:01:20 2011 Message-Id: <20110826220120.632723223@clark.kroah.org> User-Agent: quilt/0.48-16.4 Date: Fri, 26 Aug 2011 14:58:31 -0700 From: Greg KH To: linux-kernel@vger.kernel.org, stable@kernel.org Cc: stable-review@kernel.org, torvalds@linux-foundation.org, akpm@linux-foundation.org, alan@lxorguk.ukuu.org.uk, Timo Warns , Matt Domsch , Eugene Teo , Dave Jones Subject: [10/19] fs/partitions/efi.c: corrupted GUID partition tables can cause kernel oops In-Reply-To: <20110826220137.GA14059@kroah.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 2.6.32-longterm review patch. If anyone has any objections, please let us know. ------------------ From: Timo Warns commit 3eb8e74ec72736b9b9d728bad30484ec89c91dde upstream. 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 Cc: Matt Domsch Cc: Eugene Teo Cc: Dave Jones Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds [dannf: backported to Debian's 2.6.32] Signed-off-by: Greg Kroah-Hartman --- fs/partitions/efi.c | 9 +++++++++ 1 file changed, 9 insertions(+) --- a/fs/partitions/efi.c +++ b/fs/partitions/efi.c @@ -311,6 +311,15 @@ is_gpt_valid(struct block_device *bdev, goto fail; } + /* Check the GUID Partition Table header size */ + if (le32_to_cpu((*gpt)->header_size) > + bdev_logical_block_size(bdev)) { + pr_debug("GUID Partition Table Header size is wrong: %u > %u\n", + le32_to_cpu((*gpt)->header_size), + bdev_logical_block_size(bdev)); + goto fail; + } + /* Check the GUID Partition Table CRC */ origcrc = le32_to_cpu((*gpt)->header_crc32); (*gpt)->header_crc32 = 0;