commit bdb2381d3a4ac48c76f90abe31fce3e380b16bf3
author Linux Build Service Account <lnxbuild@localhost> Tue Nov 05 18:39:39 2013 -0800
committer Gerrit - the friendly Code Review server <code-review@localhost> Tue Nov 05 18:39:39 2013 -0800
tree ed7fd9de27311caf8dddef18019cc07554fe5e76
parent 936b053c1df33d979fcc928aefc8e21598f2f960
parent c105e98df656e3569d596f7d778a2f0298f047a3

Merge "zram: avoid access beyond the zram device"

drivers/staging/zram/zram_drv.c

diff --git a/drivers/staging/zram/zram_drv.c b/drivers/staging/zram/zram_drv.c
index f760361..9f097ce 100644
--- a/drivers/staging/zram/zram_drv.c
+++ b/drivers/staging/zram/zram_drv.c
@@ -420,13 +420,20 @@
  */
 static inline int valid_io_request(struct zram *zram, struct bio *bio)
 {
-	if (unlikely(
-		(bio->bi_sector >= (zram->disksize >> SECTOR_SHIFT)) ||
-		(bio->bi_sector & (ZRAM_SECTOR_PER_LOGICAL_BLOCK - 1)) ||
-		(bio->bi_size & (ZRAM_LOGICAL_BLOCK_SIZE - 1)))) {
-
+	u64 start, end, bound;
+	
+	/* unaligned request */
+	if (unlikely(bio->bi_sector & (ZRAM_SECTOR_PER_LOGICAL_BLOCK - 1)))
 		return 0;
-	}
+	if (unlikely(bio->bi_size & (ZRAM_LOGICAL_BLOCK_SIZE - 1)))
+		return 0;
+
+	start = bio->bi_sector;
+	end = start + (bio->bi_size >> SECTOR_SHIFT);
+	bound = zram->disksize >> SECTOR_SHIFT;
+	/* out of range range */
+	if (unlikely(start >= bound || end >= bound || start > end))
+		return 0;
 
 	/* I/O request is valid */
 	return 1;