Messages in this thread Patch in this message |  | | From | Yu Kuai <> | Subject | [PATCH] block, bfq: fix uaf for bfqq in bfq_exit_icq_bfqq | Date | Mon, 26 Dec 2022 11:06:05 +0800 |
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From: Yu Kuai <yukuai3@huawei.com>
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> --- block/bfq-iosched.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/block/bfq-iosched.c b/block/bfq-iosched.c index 16f43bbc575a..ccf2204477a5 100644 --- a/block/bfq-iosched.c +++ b/block/bfq-iosched.c @@ -5317,8 +5317,8 @@ static void bfq_exit_icq_bfqq(struct bfq_io_cq *bic, bool is_sync) unsigned long flags; spin_lock_irqsave(&bfqd->lock, flags); - bfq_exit_bfqq(bfqd, bfqq); bic_set_bfqq(bic, NULL, is_sync); + bfq_exit_bfqq(bfqd, bfqq); spin_unlock_irqrestore(&bfqd->lock, flags); } } -- 2.31.1
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