This is a note to let you know that I've just added the patch titled
genhd: check for int overflow in disk_expand_part_tbl()
to the 3.14-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:
genhd-check-for-int-overflow-in-disk_expand_part_tbl.patch
and it can be found in the queue-3.14 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 5fabcb4c33fe11c7e3afdf805fde26c1a54d0953 Mon Sep 17 00:00:00 2001
From: Jens Axboe <axboe@xxxxxx>
Date: Wed, 19 Nov 2014 13:06:22 -0700
Subject: genhd: check for int overflow in disk_expand_part_tbl()
From: Jens Axboe <axboe@xxxxxx>
commit 5fabcb4c33fe11c7e3afdf805fde26c1a54d0953 upstream.
We can get here from blkdev_ioctl() -> blkpg_ioctl() -> add_partition()
with a user passed in partno value. If we pass in 0x7fffffff, the
new target in disk_expand_part_tbl() overflows the 'int' and we
access beyond the end of ptbl->part[] and even write to it when we
do the rcu_assign_pointer() to assign the new partition.
Reported-by: David Ramos <daramos@xxxxxxxxxxxx>
Signed-off-by: Jens Axboe <axboe@xxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
block/genhd.c | 11 +++++++++--
1 file changed, 9 insertions(+), 2 deletions(-)
--- a/block/genhd.c
+++ b/block/genhd.c
@@ -1070,9 +1070,16 @@ int disk_expand_part_tbl(struct gendisk
struct disk_part_tbl *old_ptbl = disk->part_tbl;
struct disk_part_tbl *new_ptbl;
int len = old_ptbl ? old_ptbl->len : 0;
- int target = partno + 1;
+ int i, target;
size_t size;
- int i;
+
+ /*
+ * check for int overflow, since we can get here from blkpg_ioctl()
+ * with a user passed 'partno'.
+ */
+ target = partno + 1;
+ if (target < 0)
+ return -EINVAL;
/* disk_max_parts() is zero during initialization, ignore if so */
if (disk_max_parts(disk) && target > disk_max_parts(disk))
Patches currently in stable-queue which might be from axboe@xxxxxx are
queue-3.14/genhd-check-for-int-overflow-in-disk_expand_part_tbl.patch
queue-3.14/blk-mq-use-nr_cpu_ids-as-highest-cpu-id-count-for-hwq-cpu-map.patch
queue-3.14/writeback-fix-a-subtle-race-condition-in-i_dirty-clearing.patch
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