[PATCH 3/3] partitions: efi: check minimum header size

From: Davidlohr Bueso
Date: Wed Sep 05 2012 - 05:18:38 EST


As per UEFI specs 2.3.1 (June 2012),
"The Header Size must be greater than 92 and must be less than
or equal to the logical block size"

Signed-off-by: Davidlohr Bueso <dave@xxxxxxx>
---
block/partitions/efi.c | 7 +++++--
1 files changed, 5 insertions(+), 2 deletions(-)

diff --git a/block/partitions/efi.c b/block/partitions/efi.c
index abf33a2..3a5114e 100644
--- a/block/partitions/efi.c
+++ b/block/partitions/efi.c
@@ -25,6 +25,9 @@
* TODO:
*
* Changelog:
+ * Sept. 2012 Davidlohr Bueso <dave@xxxxxxx>
+ * - tighten GPT header integrity verification.
+ *
* Mon Nov 09 2004 Matt Domsch <Matt_Domsch@xxxxxxxx>
* - test for valid PMBR and valid PGPT before ever reading
* AGPT, allow override with 'gpt' kernel command line option.
@@ -311,8 +314,8 @@ static int is_gpt_valid(struct parsed_partitions *state, u64 lba,
}

/* Check the GUID Partition Table header size */
- if (le32_to_cpu((*gpt)->header_size) >
- bdev_logical_block_size(state->bdev)) {
+ if (le32_to_cpu((*gpt)->header_size) <= 92 ||
+ le32_to_cpu((*gpt)->header_size) > bdev_logical_block_size(state->bdev)) {
pr_debug("GUID Partition Table Header size is wrong: %u > %u\n",
le32_to_cpu((*gpt)->header_size),
bdev_logical_block_size(state->bdev));
--
1.7.4.1




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