Merge branch 'net-sched-fix-memory-leak-on-mirred-loop'

Jamal Hadi Salim says:

====================
net/sched: Fix memory leak on mirred loop

Initialize at_ingress earlier before the if statement.
====================

Link: https://patch.msgid.link/[e-mail]
Signed-off-by: Jakub Kicinski <[e-mail]>

net/sched/act_mirred.c

···
 		goto err_cant_do;
 	}
 
-	/* we could easily avoid the clone only if called by ingress and clsact;
-	 * since we can't easily detect the clsact caller, skip clone only for
-	 * ingress - that covers the TC S/W datapath.
-	 */
-	at_ingress = skb_at_tc_ingress(skb);
-	dont_clone = skb_at_tc_ingress(skb) && is_redirect &&
-		tcf_mirred_can_reinsert(retval);
-	if (!dont_clone) {
-		skb_to_send = skb_clone(skb, GFP_ATOMIC);
-		if (!skb_to_send)
-			goto err_cant_do;
-	}
-
 	want_ingress = tcf_mirred_act_wants_ingress(m_eaction);
 
+	at_ingress = skb_at_tc_ingress(skb);
 	if (dev == skb->dev && want_ingress == at_ingress) {
 		pr_notice_once("tc mirred: Loop (%s:%s --> %s:%s)\n",
 			       netdev_name(skb->dev),
···
 			       netdev_name(dev),
 			       want_ingress ? "ingress" : "egress");
 		goto err_cant_do;
+	}
+
+	/* we could easily avoid the clone only if called by ingress and clsact;
+	 * since we can't easily detect the clsact caller, skip clone only for
+	 * ingress - that covers the TC S/W datapath.
+	 */
+	dont_clone = skb_at_tc_ingress(skb) && is_redirect &&
+		tcf_mirred_can_reinsert(retval);
+	if (!dont_clone) {
+		skb_to_send = skb_clone(skb, GFP_ATOMIC);
+		if (!skb_to_send)
+			goto err_cant_do;
 	}
 
 	/* All mirred/redirected skbs should clear previous ct info */

tools/testing/selftests/tc-testing/tc-tests/actions/mirred.json

···
         "teardown": [
             "$TC qdisc del dev $DUMMY root"
         ]
+    },
+    {
+        "id": "4ed9",
+        "name": "Try to redirect to self on egress with clsact",
+        "category": [
+            "filter",
+            "mirred"
+        ],
+        "plugins": {
+            "requires": [
+                "nsPlugin"
+            ]
+        },
+        "setup": [
+            "$IP link set dev $DUMMY up || true",
+            "$IP addr add 10.10.10.10/24 dev $DUMMY || true",
+            "$TC qdisc add dev $DUMMY clsact",
+            "$TC filter add dev $DUMMY egress protocol ip prio 10 matchall action mirred egress redirect dev $DUMMY index 1"
+        ],
+        "cmdUnderTest": "ping -c1 -W0.01 -I $DUMMY 10.10.10.1",
+        "expExitCode": "1",
+        "verifyCmd": "$TC -j -s actions get action mirred index 1",
+        "matchJSON": [
+            {
+                "total acts": 0
+            },
+            {
+                "actions": [
+                    {
+                        "order": 1,
+                        "kind": "mirred",
+                        "mirred_action": "redirect",
+                        "direction": "egress",
+                        "index": 1,
+                        "stats": {
+                            "packets": 1,
+                            "overlimits": 1
+                        },
+                        "not_in_hw": true
+                    }
+                ]
+            }
+        ],
+        "teardown": [
+            "$TC qdisc del dev $DUMMY clsact"
+        ]
     }
+
 ]