From:   Pavel Skripkin <paskripkin@gmail.com>
To:     zyjzyj2000@gmail.com, dledford@redhat.com, jgg@ziepe.ca,
        leon@kernel.org
Cc:     linux-rdma@vger.kernel.org, linux-kernel@vger.kernel.org,
        Pavel Skripkin <paskripkin@gmail.com>,
        syzbot+aab53008a5adf26abe91@syzkaller.appspotmail.com
Subject: [PATCH] RDMA: fix use-after-free in rxe_queue_cleanup
Date:   Sun, 21 Nov 2021 23:22:39 +0300
Message-Id: <20211121202239.3129-1-paskripkin@gmail.com>
In-Reply-To: <YZpUnR05mK6taHs9@unreal>
References: <YZpUnR05mK6taHs9@unreal>
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
Precedence: bulk

On error handling path in rxe_qp_from_init() qp->sq.queue is freed and
then rxe_create_qp() will drop last reference to this object. qp clean
up function will try to free this queue one time and it causes UAF bug.

Fix it by zeroing queue pointer after freeing queue in
rxe_qp_from_init().

Fixes: 514aee660df4 ("RDMA: Globally allocate and release QP memory")
Reported-by: syzbot+aab53008a5adf26abe91@syzkaller.appspotmail.com
Signed-off-by: Pavel Skripkin <paskripkin@gmail.com>
---
 drivers/infiniband/sw/rxe/rxe_qp.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/infiniband/sw/rxe/rxe_qp.c b/drivers/infiniband/sw/rxe/rxe_qp.c
index 975321812c87..54b8711321c1 100644
--- a/drivers/infiniband/sw/rxe/rxe_qp.c
+++ b/drivers/infiniband/sw/rxe/rxe_qp.c
@@ -359,6 +359,7 @@ int rxe_qp_from_init(struct rxe_dev *rxe, struct rxe_qp *qp, struct rxe_pd *pd,
 
 err2:
 	rxe_queue_cleanup(qp->sq.queue);
+	qp->sq.queue = NULL;
 err1:
 	qp->pd = NULL;
 	qp->rcq = NULL;
-- 
2.33.1