[PATCH] RDMA: fix use-after-free in rxe_queue_cleanup

From: Pavel Skripkin
Date: Sun Nov 21 2021 - 15:22:50 EST

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

Fixes: 514aee660df4 ("RDMA: Globally allocate and release QP memory")
Reported-by: syzbot+aab53008a5adf26abe91@xxxxxxxxxxxxxxxxxxxxxxxxx
Signed-off-by: Pavel Skripkin <paskripkin@xxxxxxxxx>
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,

+ qp->sq.queue = NULL;
qp->pd = NULL;
qp->rcq = NULL;