On Wed, 2013-02-13 at 18:15 -0500, Peter Jones wrote:
> UEFI 2.3.1D will include a change to the spec language mandating that a
> GPT header must be greater than *or equal to* the size of the defined
> structure. While verifying that this would work on Linux, I discovered
> that we're not actually checking the minimum bound at all.
>
> The result of this is that when we verify the checksum, it's possible
> that on a malformed header (with header_size of 0), we won't actually
> verify any data.
>
> (ammended to fix type error in pr_debug())
>
> Signed-off-by: Peter Jones <pjo...@redhat.com>
> ---
> block/partitions/efi.c | 12 ++++++++++--
> 1 file changed, 10 insertions(+), 2 deletions(-)
>
> diff --git a/block/partitions/efi.c b/block/partitions/efi.c
> index b62fb88..a7475e7 100644
> --- a/block/partitions/efi.c
> +++ b/block/partitions/efi.c
> @@ -310,15 +310,23 @@ static int is_gpt_valid(struct parsed_partitions
> *state, u64 lba,
> goto fail;
> }
>
> - /* Check the GUID Partition Table header size */
> + /* Check the GUID Partition Table header size is too big */
> if (le32_to_cpu((*gpt)->header_size) >
> bdev_logical_block_size(state->bdev)) {
> - pr_debug("GUID Partition Table Header size is wrong: %u > %u\n",
> + pr_debug("GUID Partition Table Header size is too large: %u >
> %u\n",
> le32_to_cpu((*gpt)->header_size),
> bdev_logical_block_size(state->bdev));
> goto fail;
> }
>
> + /* Check the GUID Partition Table header size is too small */
> + if (le32_to_cpu((*gpt)->header_size) < sizeof(gpt_header)) {
> + pr_debug("GUID Partition Table Header size is too small: %u <
> %lu\n",
> + le32_to_cpu((*gpt)->header_size),
> + sizeof(gpt_header));
> + goto fail;
> + }
> +
> /* Check the GUID Partition Table CRC */
> origcrc = le32_to_cpu((*gpt)->header_crc32);
> (*gpt)->header_crc32 = 0;
Seems straight forward.
Acked-by: Matt Fleming <matt.flem...@intel.com>
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