[PATCH 4.16 102/196] RDMA/ucma: Dont allow setting RDMA_OPTION_IB_PATH without an RDMA device

[Greg Kroah-Hartman]

4.16-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Roland Dreier <roland@xxxxxxxxxxxxxxx>

commit 8435168d50e66fa5eae01852769d20a36f9e5e83 upstream.

Check to make sure that ctx->cm_id->device is set before we use it.
Otherwise userspace can trigger a NULL dereference by doing
RDMA_USER_CM_CMD_SET_OPTION on an ID that is not bound to a device.

Cc: <stable@xxxxxxxxxxxxxxx>
Reported-by: <syzbot+a67bc93e14682d92fc2f@xxxxxxxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Roland Dreier <roland@xxxxxxxxxxxxxxx>
Signed-off-by: Jason Gunthorpe <jgg@xxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
 drivers/infiniband/core/ucma.c |    3 +++
 1 file changed, 3 insertions(+)

--- a/drivers/infiniband/core/ucma.c
+++ b/drivers/infiniband/core/ucma.c
@@ -1241,6 +1241,9 @@ static int ucma_set_ib_path(struct ucma_
 	if (!optlen)
 		return -EINVAL;
 
+	if (!ctx->cm_id->device)
+		return -EINVAL;
+
 	memset(&sa_path, 0, sizeof(sa_path));
 
 	sa_path.rec_type = SA_PATH_REC_TYPE_IB;