[PATCH 4.12 166/196] RDMA/uverbs: Fix the check for port number

[Greg Kroah-Hartman]

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

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

From: Ismail, Mustafa <mustafa.ismail@xxxxxxxxx>

commit 5a7a88f1b488e4ee49eb3d5b82612d4d9ffdf2c3 upstream.

The port number is only valid if IB_QP_PORT is set in the mask.
So only check port number if it is valid to prevent modify_qp from
failing due to an invalid port number.

Fixes: 5ecce4c9b17b("Check port number supplied by user verbs cmds")
Reviewed-by: Steve Wise <swise@xxxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Mustafa Ismail <mustafa.ismail@xxxxxxxxx>
Tested-by: Mike Marciniszyn <mike.marciniszyn@xxxxxxxxx>
Signed-off-by: Doug Ledford <dledford@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
 drivers/infiniband/core/uverbs_cmd.c |    3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

--- a/drivers/infiniband/core/uverbs_cmd.c
+++ b/drivers/infiniband/core/uverbs_cmd.c
@@ -1931,7 +1931,8 @@ static int modify_qp(struct ib_uverbs_fi
 		goto out;
 	}
 
-	if (!rdma_is_port_valid(qp->device, cmd->base.port_num)) {
+	if ((cmd->base.attr_mask & IB_QP_PORT) &&
+	    !rdma_is_port_valid(qp->device, cmd->base.port_num)) {
 		ret = -EINVAL;
 		goto release_qp;
 	}