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

After commit 64dc8c732f ("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: 64dc8c732f ("block, bfq: fix possible uaf for 'bfqq->bic'")
Reported-and-tested-by: Shinichiro Kawasaki <shinichiro.kawasaki@wdc.com>
Signed-off-by: Yu Kuai <yukuai3@huawei.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Link: https://lore.kernel.org/r/20230130014136.591038-1-yukuai1@huaweicloud.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
This commit is contained in:
Yu Kuai 2023-01-30 09:41:36 +08:00 committed by Jens Axboe
parent db3ba974c2
commit b600de2d7d
2 changed files with 4 additions and 2 deletions
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2
block/bfq-cgroup.c
View File

@ -769,8 +769,8 @@ static void __bfq_bic_change_cgroup(struct bfq_data *bfqd,
* request from the old cgroup.
*/
bfq_put_cooperator(sync_bfqq);
bfq_release_process_ref(bfqd, sync_bfqq);
bic_set_bfqq(bic, NULL, true);
bfq_release_process_ref(bfqd, sync_bfqq);
}
}
}

4
block/bfq-iosched.c
View File

@ -5425,9 +5425,11 @@ static void bfq_check_ioprio_change(struct bfq_io_cq *bic, struct bio *bio)
bfqq = bic_to_bfqq(bic, false);
if (bfqq) {
bfq_release_process_ref(bfqd, bfqq);
struct bfq_queue *old_bfqq = bfqq;
bfqq = bfq_get_queue(bfqd, bio, false, bic, true);
bic_set_bfqq(bic, bfqq, false);
bfq_release_process_ref(bfqd, old_bfqq);
}
bfqq = bic_to_bfqq(bic, true);