partitions/efi: check pmbr record's starting lba

Per the UEFI Specs 2.4, June 2013, the starting lba of the partition that has the EFI GPT (0xEE) must be set to 0x00000001 - this is obviously the LBA of the GPT Partition Header. [[email protected]: coding-style fixes] Signed-off-by: Davidlohr Bueso <[email protected]> Reviewed-by: Karel Zak <[email protected]> Acked-by: Matt Fleming <[email protected]> Signed-off-by: Andrew Morton <[email protected]> Signed-off-by: Linus Torvalds <[email protected]>
iegor · Sep 11, 2013 · 33afd7a · 33afd7a
1 parent c2ebdc2
commit 33afd7a
Showing 1 changed file with 13 additions and 4 deletions.
diff --git a/block/partitions/efi.c b/block/partitions/efi.c
@@ -151,10 +151,19 @@ static u64 last_lba(struct block_device *bdev)
 
 static inline int pmbr_part_valid(gpt_mbr_record *part)
 {
-	if (part->os_type == EFI_PMBR_OSTYPE_EFI_GPT &&
-	    le32_to_cpu(part->start_sector) == 1UL)
-		return 1;
-        return 0;
+	if (part->os_type != EFI_PMBR_OSTYPE_EFI_GPT)
+		goto invalid;
+
+	/* set to 0x00000001 (i.e., the LBA of the GPT Partition Header) */
+	if (le32_to_cpu(part->starting_lba) != GPT_PRIMARY_PARTITION_TABLE_LBA)
+		goto invalid;
+
+	if (le32_to_cpu(part->start_sector) != 1UL)
+		goto invalid;
+
+	return 1;
+invalid:
+	return 0;
 }
 
 /**