RDMA: Fix use-after-free in rxe_queue_cleanup

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: 0a422dec2a13 ("RDMA: Globally allocate and release QP memory")
Link: https://lore.kernel.org/r/20211121202239.3129-1-paskripkin@gmail.com
Reported-by: syzbot+aab53008a5adf26abe91@syzkaller.appspotmail.com
Signed-off-by: Pavel Skripkin <paskripkin@gmail.com>
Reviewed-by: Zhu Yanjun <zyjzyj2000@gmail.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>

diff --git a/drivers/infiniband/sw/rxe/rxe_qp.c b/drivers/infiniband/sw/rxe/rxe_qp.c
index 975321812c870ff544c39a560ed7dd6a8d6ffc06..54b8711321c1e58753e7df39af6d404dc63ff443 100644 (file)
--- 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;