From: Yu Kuai Date: Mon, 30 Jan 2023 01:41:36 +0000 (+0800) Subject: block, bfq: fix uaf for bfqq in bic_set_bfqq() X-Git-Tag: baikal/aarch64/sdk6.1~160 X-Git-Url: https://git.baikalelectronics.ru/sdk/?a=commitdiff_plain;h=8e2e62f20df8b51ab2dbaed33e77d10c9afcf729;p=kernel.git 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 --- diff --git a/block/bfq-cgroup.c b/block/bfq-cgroup.c index dfb6d1d8bd464..60b4299bec8ec 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 917939b60ef8b..ff9d238894157 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);