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| author | Timo Warns <Warns@pre-sense.de> | 2011-05-26 16:25:57 -0700 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@suse.de> | 2011-08-29 14:08:05 -0700 |
| commit | 098c4cab3a9eaf734d7d99feb55a521be90da37d (patch) | |
| tree | 4415297e76d9d4eafce44f9c76992045049a94d4 | |
| parent | b871297c35fbf85aeaa1f2776bd37c666089da26 (diff) | |
| download | lwn-098c4cab3a9eaf734d7d99feb55a521be90da37d.tar.gz lwn-098c4cab3a9eaf734d7d99feb55a521be90da37d.zip | |
fs/partitions/efi.c: corrupted GUID partition tables can cause kernel oops
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 <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>
[dannf: backported to Debian's 2.6.32]
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
| -rw-r--r-- | fs/partitions/efi.c | 9 |
1 files changed, 9 insertions, 0 deletions
diff --git a/fs/partitions/efi.c b/fs/partitions/efi.c index 2aac7764b7e5..6ab70f413a57 100644 --- a/fs/partitions/efi.c +++ b/fs/partitions/efi.c @@ -311,6 +311,15 @@ is_gpt_valid(struct block_device *bdev, u64 lba, 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; |