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| author | Jens Axboe <axboe@fb.com> | 2014-11-19 13:06:22 -0700 |
|---|---|---|
| committer | Jens Axboe <axboe@fb.com> | 2014-11-19 13:09:07 -0700 |
| commit | 5fabcb4c33fe11c7e3afdf805fde26c1a54d0953 (patch) | |
| tree | 7a30365f099b4c180bf8fed77842c0d60b4df8a2 /block/genhd.c | |
| parent | 7c7f2f2bc9a63f9605a16eabac59fc655dfe7c9a (diff) | |
| download | lwn-5fabcb4c33fe11c7e3afdf805fde26c1a54d0953.tar.gz lwn-5fabcb4c33fe11c7e3afdf805fde26c1a54d0953.zip | |
genhd: check for int overflow in disk_expand_part_tbl()
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>
Cc: stable@kernel.org
Signed-off-by: Jens Axboe <axboe@fb.com>
Diffstat (limited to 'block/genhd.c')
| -rw-r--r-- | block/genhd.c | 11 |
1 files changed, 9 insertions, 2 deletions
diff --git a/block/genhd.c b/block/genhd.c index bd3060684ab2..0a536dc05f3b 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)) |