[PATCH 5.15 03/42] RDMA: Fix use-after-free in rxe_queue_cleanup

[Greg Kroah-Hartman]

From: Pavel Skripkin <paskripkin@xxxxxxxxx>

[ Upstream commit 84b01721e8042cdd1e8ffeb648844a09cd4213e0 ]

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")
Link: https://lore.kernel.org/r/20211121202239.3129-1-paskripkin@xxxxxxxxx
Reported-by: syzbot+aab53008a5adf26abe91@xxxxxxxxxxxxxxxxxxxxxxxxx
Signed-off-by: Pavel Skripkin <paskripkin@xxxxxxxxx>
Reviewed-by: Zhu Yanjun <zyjzyj2000@xxxxxxxxx>
Signed-off-by: Jason Gunthorpe <jgg@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
 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 1ab6af7ddb254..ed326d82725cd 100644
--- a/drivers/infiniband/sw/rxe/rxe_qp.c
+++ b/drivers/infiniband/sw/rxe/rxe_qp.c
@@ -367,6 +367,7 @@ 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;
-- 
2.33.0