block, bfq: fix uaf for bfqq in bfq_exit_icq_bfqq
authorYu Kuai <yukuai3@huawei.com>
Mon, 26 Dec 2022 03:06:05 +0000 (11:06 +0800)
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Wed, 4 Jan 2023 10:28:51 +0000 (11:28 +0100)
commit1ed959fef5b1c6f1a7a3fbea543698c30ebd6678
tree77e0a6acb57eb3488d341f901f37a9ee90424ca5
parent5fe70f9683f872e63793edf098a89fe95e5fca95
block, bfq: fix uaf for bfqq in bfq_exit_icq_bfqq

[ Upstream commit 246cf66e300b76099b5dbd3fdd39e9a5dbc53f02 ]

Commit 64dc8c732f5c ("block, bfq: fix possible uaf for 'bfqq->bic'")
will access 'bic->bfqq' in bic_set_bfqq(), however, bfq_exit_icq_bfqq()
can free bfqq first, and then call bic_set_bfqq(), which will cause uaf.

Fix the problem by moving bfq_exit_bfqq() behind bic_set_bfqq().

Fixes: 64dc8c732f5c ("block, bfq: fix possible uaf for 'bfqq->bic'")
Reported-by: Yi Zhang <yi.zhang@redhat.com>
Signed-off-by: Yu Kuai <yukuai3@huawei.com>
Link: https://lore.kernel.org/r/20221226030605.1437081-1-yukuai1@huaweicloud.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Sasha Levin <sashal@kernel.org>
block/bfq-iosched.c