This is a note to let you know that I've just added the patch titled
zram: avoid access beyond the zram device
to the 3.4-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
zram-avoid-access-beyond-the-zram-device.patch
and it can be found in the queue-3.4 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <[email protected]> know about it.
>From 624d1705fa1d6e4c647ca5859ecd921748bd85bf Mon Sep 17 00:00:00 2001
From: Jiang Liu <[email protected]>
Date: Fri, 7 Jun 2013 00:07:26 +0800
Subject: zram: avoid access beyond the zram device
From: Jiang Liu <[email protected]>
commit 12a7ad3b810e77137d0caf97a6dd97591e075b30 upstream.
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 <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
Signed-off-by: Ben Hutchings <[email protected]>
Cc: Jianguo Wu <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
---
drivers/staging/zram/zram_drv.c | 17 ++++++++++++-----
1 file changed, 12 insertions(+), 5 deletions(-)
--- a/drivers/staging/zram/zram_drv.c
+++ b/drivers/staging/zram/zram_drv.c
@@ -535,13 +535,20 @@ 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;
Patches currently in stable-queue which might be from [email protected] are
queue-3.4/zram-avoid-invalid-memory-access-in-zram_exit.patch
queue-3.4/zram-destroy-all-devices-on-error-recovery-path-in-zram_init.patch
queue-3.4/zram-avoid-access-beyond-the-zram-device.patch
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