block: validate pi_offset integrity limit

The PI tuple must be contained within the metadata value, so validate
that pi_offset + pi_tuple_size <= metadata_size. This guards against
block drivers that report invalid pi_offset values.

Signed-off-by: Caleb Sander Mateos <csander@purestorage.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

Author: calebsander

block/blk-settings.c

@@ -161,10 +161,9 @@ static int blk_validate_integrity_limits(struct queue_limits *lim)
 		return -EINVAL;
 	}
 
-	if (bi->pi_tuple_size > bi->metadata_size) {
-		pr_warn("pi_tuple_size (%u) exceeds metadata_size (%u)\n",
-			 bi->pi_tuple_size,
-			 bi->metadata_size);
+	if (bi->pi_offset + bi->pi_tuple_size > bi->metadata_size) {
+		pr_warn("pi_offset (%u) + pi_tuple_size (%u) exceeds metadata_size (%u)\n",
+			bi->pi_offset, bi->pi_tuple_size, bi->metadata_size);
 		return -EINVAL;
 	}