loop: remove union of use_aio and ref in struct loop_cmd

When the request is completed, lo_complete_rq() checks cmd->use_aio.
However, if this is in fact an aio request, cmd->use_aio will have
already been reused as cmd->ref by lo_rw_aio*. Fix it by not using a
union. On x86_64, there's a hole after the union anyways, so this
doesn't make struct loop_cmd any bigger.

Fixes: 92d773324b ("block/loop: fix use after free")
Signed-off-by: Omar Sandoval <osandov@fb.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
This commit is contained in:
Omar Sandoval 2017-09-20 14:24:34 -07:00 committed by Jens Axboe
parent 5acb3cc2c2
commit e5313c141b

View File

@ -67,10 +67,8 @@ struct loop_device {
struct loop_cmd {
struct kthread_work work;
struct request *rq;
union {
bool use_aio; /* use AIO interface to handle I/O */
atomic_t ref; /* only for aio */
};
bool use_aio; /* use AIO interface to handle I/O */
atomic_t ref; /* only for aio */
long ret;
struct kiocb iocb;
struct bio_vec *bvec;