Subject: [PATCH 1/2 net-next] net: mscc: ocelot: fix error handling bugs in mscc_ocelot_init_ports()

From: Dan Carpenter <[email-masked]>
Date: Mon, 25 Jan 2021 11:12:42 +0300

There are several error handling bugs in mscc_ocelot_init_ports().  I
went through the code, and carefully audited it and made fixes and
cleanups.

1) The ocelot_probe_port() function didn't have a mirror release function
   so it was hard to follow.  I created the ocelot_release_port()
   function.
2) In the ocelot_probe_port() function, if the register_netdev() call
   failed, then it lead to a double free_netdev(dev) bug.  Fix this
   by moving the "ocelot->ports[port] = ocelot_port;" assignment to the
   end of the function after everything has succeeded.
3) I was concerned that the "port" which comes from of_property_read_u32()
   might be out of bounds so I added a check for that.
4) In the original code if ocelot_regmap_init() failed then the driver
   tried to continue but I think that should be a fatal error.
5) If ocelot_probe_port() failed then the most recent devlink was leaked.
   Fix this by moving the "registered_ports[port] = true;" assignment
   earlier.
6) The error handling if the final ocelot_port_devlink_init() failed had
   two problems.  The "while (port-- >= 0)" loop should have been
   "--port" pre-op instead of a post-op to avoid a buffer underflow.
   The "if (!registered_ports[port])" condition was reversed leading to
   resource leaks and double frees.

Fixes: 6c30384eb1de ("net: mscc: ocelot: register devlink ports")
Signed-off-by: Dan Carpenter <[email-masked]>
---
 drivers/net/ethernet/mscc/ocelot_vsc7514.c | 39 +++++++++-------------
 1 file changed, 16 insertions(+), 23 deletions(-)

diff --git a/drivers/net/ethernet/mscc/ocelot_vsc7514.c b/drivers/net/ethernet/mscc/ocelot_vsc7514.c
index 30a38df08a21..2c82ffe2c611 100644
--- a/drivers/net/ethernet/mscc/ocelot_vsc7514.c
+++ b/drivers/net/ethernet/mscc/ocelot_vsc7514.c
@@ -1064,7 +1064,6 @@ static void mscc_ocelot_release_ports(struct ocelot *ocelot)
 	int port;
 
 	for (port = 0; port < ocelot->num_phys_ports; port++) {
-		struct ocelot_port_private *priv;
 		struct ocelot_port *ocelot_port;
 
 		ocelot_port = ocelot->ports[port];
@@ -1072,12 +1071,7 @@ static void mscc_ocelot_release_ports(struct ocelot *ocelot)
 			continue;
 
 		ocelot_deinit_port(ocelot, port);
-
-		priv = container_of(ocelot_port, struct ocelot_port_private,
-				    port);
-
-		unregister_netdev(priv->dev);
-		free_netdev(priv->dev);
+		ocelot_release_port(ocelot_port);
 	}
 }
 
@@ -1123,14 +1117,22 @@ static int mscc_ocelot_init_ports(struct platform_device *pdev,
 			continue;
 
 		port = reg;
+		if (port < 0 || port >= ocelot->num_phys_ports) {
+			dev_err(ocelot->dev,
+				"invalid port number: %d >= %d\n", port,
+				ocelot->num_phys_ports);
+			continue;
+		}
 
 		snprintf(res_name, sizeof(res_name), "port%d", port);
 
 		res = platform_get_resource_byname(pdev, IORESOURCE_MEM,
 						   res_name);
 		target = ocelot_regmap_init(ocelot, res);
-		if (IS_ERR(target))
-			continue;
+		if (IS_ERR(target)) {
+			err = PTR_ERR(target);
+			goto out_teardown;
+		}
 
 		phy_node = of_parse_phandle(portnp, "phy-handle", 0);
 		if (!phy_node)
@@ -1147,6 +1149,7 @@ static int mscc_ocelot_init_ports(struct platform_device *pdev,
 			of_node_put(portnp);
 			goto out_teardown;
 		}
+		registered_ports[port] = true;
 
 		err = ocelot_probe_port(ocelot, port, target, phy);
 		if (err) {
@@ -1154,8 +1157,6 @@ static int mscc_ocelot_init_ports(struct platform_device *pdev,
 			goto out_teardown;
 		}
 
-		registered_ports[port] = true;
-
 		ocelot_port = ocelot->ports[port];
 		priv = container_of(ocelot_port, struct ocelot_port_private,
 				    port);
@@ -1213,15 +1214,9 @@ static int mscc_ocelot_init_ports(struct platform_device *pdev,
 
 		err = ocelot_port_devlink_init(ocelot, port,
 					       DEVLINK_PORT_FLAVOUR_UNUSED);
-		if (err) {
-			while (port-- >= 0) {
-				if (!registered_ports[port])
-					continue;
-				ocelot_port_devlink_teardown(ocelot, port);
-			}
-
+		if (err)
 			goto out_teardown;
-		}
+		registered_ports[port] = true;
 	}
 
 	kfree(registered_ports);
@@ -1233,10 +1228,8 @@ static int mscc_ocelot_init_ports(struct platform_device *pdev,
 	mscc_ocelot_release_ports(ocelot);
 	/* Tear down devlink ports for the registered network interfaces */
 	for (port = 0; port < ocelot->num_phys_ports; port++) {
-		if (!registered_ports[port])
-			continue;
-
-		ocelot_port_devlink_teardown(ocelot, port);
+		if (registered_ports[port])
+			ocelot_port_devlink_teardown(ocelot, port);
 	}
 	kfree(registered_ports);
 	return err;
-- 
2.29.2