Function valid_io_request() should verify the entire request are within
the zram device address range. Otherwise it may cause invalid memory
access when accessing/modifying zram->meta->table[index] because the
'index' is out of range. Then it may access non-exist memory, randomly
modify memory belong to other subsystems, which is hard to track down.
Signed-off-by: Jiang Liu <jiang.liu@xxxxxxxxxx>
Cc: stable@xxxxxxxxxxxxxxx
---
drivers/staging/zram/zram_drv.c | 17 ++++++++++++-----
1 file changed, 12 insertions(+), 5 deletions(-)
diff --git a/drivers/staging/zram/zram_drv.c b/drivers/staging/zram/zram_drv.c
index 27ab824..9289217 100644
--- a/drivers/staging/zram/zram_drv.c
+++ b/drivers/staging/zram/zram_drv.c
@@ -420,13 +420,20 @@ out:
*/
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;
--
1.8.1.2
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