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Date: Wed, 13 Feb 2013 18:09:50 -0500 From: Peter Jones <pjones@...hat.com> To: Matt Fleming <matt.fleming@...el.com> Cc: Jens Axboe <axboe@...nel.dk>, linux-kernel@...r.kernel.org, Andrew Morton <akpm@...ux-foundation.org>, Stephen Warren <swarren@...dia.com>, Peter Jones <pjones@...hat.com> Subject: [PATCH] Ensure that the GPT header is at least the size of the structure. 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. Signed-off-by: Peter Jones <pjones@...hat.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..5ad168c 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 < %u\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; -- 1.8.1.2 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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