From cb1876fc33af26d00efdd473311f1b664c77c44e Mon Sep 17 00:00:00 2001 From: Yu Kuai Date: Mon, 30 Jan 2023 09:41:36 +0800 Subject: [PATCH] block, bfq: fix uaf for bfqq in bic_set_bfqq() [ Upstream commit b600de2d7d3a16f9007fad1bdae82a3951a26af2 ] After commit 64dc8c732f5c ("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: 64dc8c732f5c ("block, bfq: fix possible uaf for 'bfqq->bic'") Reported-and-tested-by: Shinichiro Kawasaki Signed-off-by: Yu Kuai Reviewed-by: Jan Kara Link: https://lore.kernel.org/r/20230130014136.591038-1-yukuai1@huaweicloud.com Signed-off-by: Jens Axboe Signed-off-by: Sasha Levin --- block/bfq-cgroup.c | 2 +- block/bfq-iosched.c | 4 +++- 2 files changed, 4 insertions(+), 2 deletions(-) diff --git a/block/bfq-cgroup.c b/block/bfq-cgroup.c index dfb6d1d..60b4299 100644 --- a/block/bfq-cgroup.c +++ b/block/bfq-cgroup.c @@ -761,8 +761,8 @@ 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); } } } diff --git a/block/bfq-iosched.c b/block/bfq-iosched.c index 917939b..ff9d238 100644 --- a/block/bfq-iosched.c +++ b/block/bfq-iosched.c @@ -5491,9 +5491,11 @@ 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); -- 2.7.4