Commit 1699b4d5 authored Jul 15, 2022 by Vladimir Oltean Committed by Jakub Kicinski Jul 18, 2022

net: dsa: fix NULL pointer dereference in dsa_port_reset_vlan_filtering



The "ds" iterator variable used in dsa_port_reset_vlan_filtering() ->
dsa_switch_for_each_port() overwrites the "dp" received as argument,
which is later used to call dsa_port_vlan_filtering() proper.

As a result, switches which do enter that code path (the ones with
vlan_filtering_is_global=true) will dereference an invalid dp in
dsa_port_reset_vlan_filtering() after leaving a VLAN-aware bridge.

Use a dedicated "other_dp" iterator variable to avoid this from
happening.

Fixes: d0004a02 ("net: dsa: remove the "dsa_to_port in a loop" antipattern from the core")
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

parent 4db2a5ef

net/dsa/port.c

+3 −2

Original line number	Diff line number	Diff line
		@@ -248,6 +248,7 @@ static void dsa_port_reset_vlan_filtering(struct dsa_port *dp,
		struct netlink_ext_ack extack = {0};
		bool change_vlan_filtering = false;
		struct dsa_switch *ds = dp->ds;
		struct dsa_port *other_dp;
		bool vlan_filtering;
		int err;

		@@ -270,8 +271,8 @@ static void dsa_port_reset_vlan_filtering(struct dsa_port *dp,
		* VLAN-aware bridge.
		*/
		if (change_vlan_filtering && ds->vlan_filtering_is_global) {
		dsa_switch_for_each_port(dp, ds) {
		struct net_device *br = dsa_port_bridge_dev_get(dp);
		dsa_switch_for_each_port(other_dp, ds) {
		struct net_device *br = dsa_port_bridge_dev_get(other_dp);

		if (br && br_vlan_enabled(br)) {
		change_vlan_filtering = false;