[PATCH net 2/6] net: mscc: ocelot: avoid use after free with deleted tc-trap rules

[Vladimir Oltean <vladimir.oltean@nxp.com>]

The error path of ocelot_flower_parse() removes a VCAP filter from
ocelot->traps, but the main deletion path - ocelot_vcap_filter_del() -
does not.

So functions such as felix_update_trapping_destinations() can still
access the freed VCAP filter via ocelot->traps.

Fix this bug by removing the filter from ocelot->traps when it gets
deleted.

Fixes: e42bd4ed09aa ("net: mscc: ocelot: keep traps in a list")
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
---
 drivers/net/ethernet/mscc/ocelot_vcap.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/net/ethernet/mscc/ocelot_vcap.c b/drivers/net/ethernet/mscc/ocelot_vcap.c
index 1e74bdb215ec..571d43e59f63 100644
--- a/drivers/net/ethernet/mscc/ocelot_vcap.c
+++ b/drivers/net/ethernet/mscc/ocelot_vcap.c
@@ -1232,6 +1232,8 @@ static void ocelot_vcap_block_remove_filter(struct ocelot *ocelot,
 		if (ocelot_vcap_filter_equal(filter, tmp)) {
 			ocelot_vcap_filter_del_aux_resources(ocelot, tmp);
 			list_del(&tmp->list);
+			if (!list_empty(&tmp->trap_list))
+				list_del(&tmp->trap_list);
 			kfree(tmp);
 		}
 	}
-- 
2.25.1