From: Yu Kuai yukuai3@huawei.com
[ 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 shinichiro.kawasaki@wdc.com Signed-off-by: Yu Kuai yukuai3@huawei.com Reviewed-by: Jan Kara jack@suse.cz Link: https://lore.kernel.org/r/20230130014136.591038-1-yukuai1@huaweicloud.com Signed-off-by: Jens Axboe axboe@kernel.dk Signed-off-by: Sasha Levin sashal@kernel.org Signed-off-by: Khazhismel Kumykov khazhy@google.com --- 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 2f440b79183d..1f9ccc661d57 100644 --- a/block/bfq-cgroup.c +++ b/block/bfq-cgroup.c @@ -748,8 +748,8 @@ 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 016d7f32af9f..6687b805bab3 100644 --- a/block/bfq-iosched.c +++ b/block/bfq-iosched.c @@ -5070,9 +5070,11 @@ 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); bic_set_bfqq(bic, bfqq, false); + bfq_release_process_ref(bfqd, old_bfqq); }
bfqq = bic_to_bfqq(bic, true);