From: Yu Kuai Date: Mon, 26 Dec 2022 03:06:05 +0000 (+0800) Subject: block, bfq: fix uaf for bfqq in bfq_exit_icq_bfqq X-Git-Tag: v6.6.7~3559^2~29 X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=246cf66e300b76099b5dbd3fdd39e9a5dbc53f02;p=platform%2Fkernel%2Flinux-starfive.git block, bfq: fix uaf for bfqq in bfq_exit_icq_bfqq 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 Signed-off-by: Yu Kuai Link: https://lore.kernel.org/r/20221226030605.1437081-1-yukuai1@huaweicloud.com Signed-off-by: Jens Axboe --- diff --git a/block/bfq-iosched.c b/block/bfq-iosched.c index 16f43bb..ccf2204 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); } }