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| author | Jens Axboe <axboe@fb.com> | 2014-11-19 13:06:22 -0700 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2015-01-16 06:59:02 -0800 |
| commit | dd4fb6fc5dd2e85e65222f0e5e1e321dec9fc2b7 (patch) | |
| tree | 9ad743249381d5460cbcc1cc0e98d20af0aa0f48 | |
| parent | edefe2069bc0d8ab1fd03dd9b141cbfec98aca8f (diff) | |
| download | lwn-dd4fb6fc5dd2e85e65222f0e5e1e321dec9fc2b7.tar.gz lwn-dd4fb6fc5dd2e85e65222f0e5e1e321dec9fc2b7.zip | |
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>
| -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 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)) |