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partitions: efi: compare first and last usable LBAs

PATCH New Davidlohr Bueso 1 participant 1 message Sep 5, 2012

Subsystems (2)
Block layer GUID partition table (GPT)
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Davidlohr Bueso

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PATCH 1/3 partitions: efi: compare first and last usable LBAs

When verifying GPT header integrity, make sure that first usable LBA is smaller than last usable LBA.

Signed-off-by Davidlohr Bueso <[email protected]>
---
 block/partitions/efi.c |    6 ++++++
 1 files changed, 6 insertions(+), 0 deletions(-)
block/partitions/efi.c +6 -0
index 6296b40..7795bb4 100644
@@ -344,6 +344,12 @@ static int is_gpt_valid(struct parsed_partitions *state, u64 lba,
 	 * within the disk.
 	 */
 	lastlba = last_lba(state->bdev);
+	if (le64_to_cpu((*gpt)->last_usable_lba) < le64_to_cpu((*gpt)->first_usable_lba)) {
+		pr_debug("GPT: last_usable_lba incorrect: %lld > %lld\n",
+			 (unsigned long long)le64_to_cpu((*gpt)->last_usable_lba),
+			 (unsigned long long)le64_to_cpu((*gpt)->first_usable_lba));
+		goto fail;
+	}
 	if (le64_to_cpu((*gpt)->first_usable_lba) > lastlba) {
 		pr_debug("GPT: first_usable_lba incorrect: %lld > %lld\n",
 			 (unsigned long long)le64_to_cpu((*gpt)->first_usable_lba),
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1.7.4.1