[PATCH 5.15 031/120] block, bfq: fix uaf for bfqq in bic_set_bfqq()

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



From: Yu Kuai <yukuai3@xxxxxxxxxx>

[ 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@xxxxxxx>
Signed-off-by: Yu Kuai <yukuai3@xxxxxxxxxx>
Reviewed-by: Jan Kara <jack@xxxxxxx>
Link: https://lore.kernel.org/r/20230130014136.591038-1-yukuai1@xxxxxxxxxxxxxxx
Signed-off-by: Jens Axboe <axboe@xxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
 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 4ac6f59a3679..53e275e377a7 100644
--- a/block/bfq-cgroup.c
+++ b/block/bfq-cgroup.c
@@ -756,8 +756,8 @@ 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 8d967a67318c..f54554906451 100644
--- a/block/bfq-iosched.c
+++ b/block/bfq-iosched.c
@@ -5359,9 +5359,11 @@ 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);
-- 
2.39.0






[Index of Archives]     [Linux Kernel]     [Kernel Development Newbies]     [Linux USB Devel]     [Video for Linux]     [Linux Audio Users]     [Yosemite Hiking]     [Linux Kernel]     [Linux SCSI]

  Powered by Linux