From: Jens Axboe <axboe@xxxxxx> 3.4.107-rc1 review patch. If anyone has any objections, please let me know. ------------------ 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: Zefan Li <lizefan@xxxxxxxxxx> --- block/genhd.c | 11 +++++++++-- 1 file changed, 9 insertions(+), 2 deletions(-) diff --git a/block/genhd.c b/block/genhd.c index 60f7e6c..7a2a8dc 100644 --- a/block/genhd.c +++ b/block/genhd.c @@ -1069,9 +1069,16 @@ int disk_expand_part_tbl(struct gendisk *disk, int partno) 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)) -- 1.9.1 -- To unsubscribe from this list: send the line "unsubscribe stable" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html