[PATCH 2/3] partitions: efi: verify header is outside usable area

[PATCH 2/3] partitions: efi: verify header is outside usable area

[Davidlohr Bueso]

The first usable logical block can be used by a GUID partition
entry, and therefore cannot be used by the header.

Signed-off-by: Davidlohr Bueso <dave@gnu.org>
---
 block/partitions/efi.c |    7 +++++++
 1 files changed, 7 insertions(+), 0 deletions(-)

diff --git a/block/partitions/efi.c b/block/partitions/efi.c
index 7795bb4..abf33a2 100644
--- a/block/partitions/efi.c
+++ b/block/partitions/efi.c
@@ -363,6 +363,13 @@ static int is_gpt_valid(struct parsed_partitions *state, u64 lba,
 		goto fail;
 	}
 
+	/* The header must be outside usable range */
+	if (le64_to_cpu((*gpt)->first_usable_lba) < lba &&
+	    le64_to_cpu((*gpt)->last_usable_lba) > lba) {
+		pr_debug("GPT: Header is inside usable area\n");
+		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");
-- 
1.7.4.1