[34-longterm 172/196] Validate size of EFI GUID partition entries.

[Paul Gortmaker]

From: Timo Warns <Warns@xxxxxxxxxxxx>

                   -------------------
    This is a commit scheduled for the next v2.6.34 longterm release.
    If you see a problem with using this for longterm, please comment.
                   -------------------

commit fa039d5f6b126fbd65eefa05db2f67e44df8f121 upstream.

Otherwise corrupted EFI partition tables can cause total confusion.

Signed-off-by: Timo Warns <warns@xxxxxxxxxxxx>
Signed-off-by: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Paul Gortmaker <paul.gortmaker@xxxxxxxxxxxxx>
---
 fs/partitions/efi.c |    6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/fs/partitions/efi.c b/fs/partitions/efi.c
index 91babda..ee59684 100644
--- a/fs/partitions/efi.c
+++ b/fs/partitions/efi.c
@@ -350,6 +350,12 @@ is_gpt_valid(struct block_device *bdev, u64 lba,
 		goto fail;
 	}
 
+	/* Check that sizeof_partition_entry has the correct value */
+	if (le32_to_cpu((*gpt)->sizeof_partition_entry) != sizeof(gpt_entry)) {
+		pr_debug("GUID Partitition Entry Size check failed.\n");
+		goto fail;
+	}
+
 	if (!(*ptes = alloc_read_gpt_entries(bdev, *gpt)))
 		goto fail;
 
-- 
1.7.9.3

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