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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 06:59:32 -0800 |
| commit | 0fa799921d850b6e3321cf6bd54c48894c4af927 (patch) | |
| tree | 20b0e64e6a1a6eb684ad36b2280c3a08d0ca4621 /block | |
| parent | 25f9cb00a7862643fe3209e3a8ab3387af2a784d (diff) | |
| download | lwn-0fa799921d850b6e3321cf6bd54c48894c4af927.tar.gz lwn-0fa799921d850b6e3321cf6bd54c48894c4af927.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>
Diffstat (limited to 'block')
| -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 e6723bd4d7a1..a8d586a729bb 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)) |