Commit b600de2d authored by Yu Kuai's avatar Yu Kuai Committed by Jens Axboe

block, bfq: fix uaf for bfqq in bic_set_bfqq()

After commit 64dc8c73 ("block, bfq: fix possible uaf for 'bfqq->bic'"),
bic->bfqq will be accessed in bic_set_bfqq(), however, in some context
bic->bfqq will be freed, and bic_set_bfqq() is called with the freed
bic->bfqq.

Fix the problem by always freeing bfqq after bic_set_bfqq().

Fixes: 64dc8c73 ("block, bfq: fix possible uaf for 'bfqq->bic'")
Reported-and-tested-by: default avatarShinichiro Kawasaki <shinichiro.kawasaki@wdc.com>
Signed-off-by: default avatarYu Kuai <yukuai3@huawei.com>
Reviewed-by: default avatarJan Kara <jack@suse.cz>
Link: https://lore.kernel.org/r/20230130014136.591038-1-yukuai1@huaweicloud.comSigned-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent db3ba974
...@@ -769,8 +769,8 @@ static void __bfq_bic_change_cgroup(struct bfq_data *bfqd, ...@@ -769,8 +769,8 @@ static void __bfq_bic_change_cgroup(struct bfq_data *bfqd,
* request from the old cgroup. * request from the old cgroup.
*/ */
bfq_put_cooperator(sync_bfqq); bfq_put_cooperator(sync_bfqq);
bfq_release_process_ref(bfqd, sync_bfqq);
bic_set_bfqq(bic, NULL, true); bic_set_bfqq(bic, NULL, true);
bfq_release_process_ref(bfqd, sync_bfqq);
} }
} }
} }
......
...@@ -5425,9 +5425,11 @@ static void bfq_check_ioprio_change(struct bfq_io_cq *bic, struct bio *bio) ...@@ -5425,9 +5425,11 @@ static void bfq_check_ioprio_change(struct bfq_io_cq *bic, struct bio *bio)
bfqq = bic_to_bfqq(bic, false); bfqq = bic_to_bfqq(bic, false);
if (bfqq) { if (bfqq) {
bfq_release_process_ref(bfqd, bfqq); struct bfq_queue *old_bfqq = bfqq;
bfqq = bfq_get_queue(bfqd, bio, false, bic, true); bfqq = bfq_get_queue(bfqd, bio, false, bic, true);
bic_set_bfqq(bic, bfqq, false); bic_set_bfqq(bic, bfqq, false);
bfq_release_process_ref(bfqd, old_bfqq);
} }
bfqq = bic_to_bfqq(bic, true); bfqq = bic_to_bfqq(bic, true);
......
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