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: v6.0.17~56 X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=cfe5b38c37720313eff0dec5517442c7ab3c9a20;p=thirdparty%2Fkernel%2Fstable.git 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 Signed-off-by: Yu Kuai Link: https://lore.kernel.org/r/20221226030605.1437081-1-yukuai1@huaweicloud.com Signed-off-by: Jens Axboe Signed-off-by: Sasha Levin --- diff --git a/block/bfq-iosched.c b/block/bfq-iosched.c index 528ca21044a57..7d2ca122362fa 100644 --- a/block/bfq-iosched.c +++ b/block/bfq-iosched.c @@ -5385,8 +5385,8 @@ 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); } }