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authorJens Axboe <axboe@fb.com>2014-11-19 13:06:22 -0700
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2015-01-16 06:59:02 -0800
commitdd4fb6fc5dd2e85e65222f0e5e1e321dec9fc2b7 (patch)
tree9ad743249381d5460cbcc1cc0e98d20af0aa0f48 /block
parentedefe2069bc0d8ab1fd03dd9b141cbfec98aca8f (diff)
downloadlinux-linaro-stable-dd4fb6fc5dd2e85e65222f0e5e1e321dec9fc2b7.tar.gz
genhd: check for int overflow in disk_expand_part_tbl()
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@stanford.edu> Signed-off-by: Jens Axboe <axboe@fb.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'block')
-rw-r--r--block/genhd.c11
1 files changed, 9 insertions, 2 deletions
diff --git a/block/genhd.c b/block/genhd.c
index e670148c3773..7694dffe9f0e 100644
--- a/block/genhd.c
+++ b/block/genhd.c
@@ -1070,9 +1070,16 @@ 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))