Merge branch 'net-sched-fixes-for-sch_qfq'

Pedro Tammela says:

====================
net/sched: fixes for sch_qfq

Patch 1 fixes a regression introduced in 6.4 where the MTU size could be
bigger than 'lmax'.

Patch 3 fixes an issue where the code doesn't account for qdisc_pkt_len()
returning a size bigger then 'lmax'.

Patches 2 and 4 are selftests for the issues above.
====================

Link: https://lore.kernel.org/r/20230711210103.597831-1-pctammela@mojatatu.com
Signed-off-by: Paolo Abeni <pabeni@redhat.com>

Author: Paolo Abeni

net/sched/sch_qfq.c

@@ -381,8 +381,13 @@ static int qfq_change_agg(struct Qdisc *sch, struct qfq_class *cl, u32 weight,
 			   u32 lmax)
 {
 	struct qfq_sched *q = qdisc_priv(sch);
-	struct qfq_aggregate *new_agg = qfq_find_agg(q, lmax, weight);
+	struct qfq_aggregate *new_agg;
 
+	/* 'lmax' can range from [QFQ_MIN_LMAX, pktlen + stab overhead] */
+	if (lmax > QFQ_MAX_LMAX)
+		return -EINVAL;
+
+	new_agg = qfq_find_agg(q, lmax, weight);
 	if (new_agg == NULL) { /* create new aggregate */
 		new_agg = kzalloc(sizeof(*new_agg), GFP_ATOMIC);
 		if (new_agg == NULL)
@@ -423,10 +428,17 @@ static int qfq_change_class(struct Qdisc *sch, u32 classid, u32 parentid,
 	else
 		weight = 1;
 
-	if (tb[TCA_QFQ_LMAX])
+	if (tb[TCA_QFQ_LMAX]) {
 		lmax = nla_get_u32(tb[TCA_QFQ_LMAX]);
-	else
+	} else {
+		/* MTU size is user controlled */
 		lmax = psched_mtu(qdisc_dev(sch));
+		if (lmax < QFQ_MIN_LMAX || lmax > QFQ_MAX_LMAX) {
+			NL_SET_ERR_MSG_MOD(extack,
+					   "MTU size out of bounds for qfq");
+			return -EINVAL;
+		}
+	}
 
 	inv_w = ONE_FP / weight;
 	weight = ONE_FP / inv_w;

tools/testing/selftests/tc-testing/tc-tests/qdiscs/qfq.json

@@ -213,5 +213,91 @@
             "$TC qdisc del dev $DUMMY handle 1: root",
             "$IP link del dev $DUMMY type dummy"
         ]
+    },
+    {
+        "id": "85ee",
+        "name": "QFQ with big MTU",
+        "category": [
+            "qdisc",
+            "qfq"
+        ],
+        "plugins": {
+            "requires": "nsPlugin"
+        },
+        "setup": [
+            "$IP link add dev $DUMMY type dummy || /bin/true",
+            "$IP link set dev $DUMMY mtu 2147483647 || /bin/true",
+            "$TC qdisc add dev $DUMMY handle 1: root qfq"
+        ],
+        "cmdUnderTest": "$TC class add dev $DUMMY parent 1: classid 1:1 qfq weight 100",
+        "expExitCode": "2",
+        "verifyCmd": "$TC class show dev $DUMMY",
+        "matchPattern": "class qfq 1:",
+        "matchCount": "0",
+        "teardown": [
+            "$IP link del dev $DUMMY type dummy"
+        ]
+    },
+    {
+        "id": "ddfa",
+        "name": "QFQ with small MTU",
+        "category": [
+            "qdisc",
+            "qfq"
+        ],
+        "plugins": {
+            "requires": "nsPlugin"
+        },
+        "setup": [
+            "$IP link add dev $DUMMY type dummy || /bin/true",
+            "$IP link set dev $DUMMY mtu 256 || /bin/true",
+            "$TC qdisc add dev $DUMMY handle 1: root qfq"
+        ],
+        "cmdUnderTest": "$TC class add dev $DUMMY parent 1: classid 1:1 qfq weight 100",
+        "expExitCode": "2",
+        "verifyCmd": "$TC class show dev $DUMMY",
+        "matchPattern": "class qfq 1:",
+        "matchCount": "0",
+        "teardown": [
+            "$IP link del dev $DUMMY type dummy"
+        ]
+    },
+    {
+        "id": "5993",
+        "name": "QFQ with stab overhead greater than max packet len",
+        "category": [
+            "qdisc",
+            "qfq",
+            "scapy"
+        ],
+        "plugins": {
+            "requires": [
+                "nsPlugin",
+                "scapyPlugin"
+            ]
+        },
+        "setup": [
+            "$IP link add dev $DUMMY type dummy || /bin/true",
+            "$IP link set dev $DUMMY up || /bin/true",
+            "$TC qdisc add dev $DUMMY handle 1: stab mtu 2048 tsize 512 mpu 0 overhead 999999999 linklayer ethernet root qfq",
+            "$TC class add dev $DUMMY parent 1: classid 1:1 qfq weight 100",
+            "$TC qdisc add dev $DEV1 clsact",
+            "$TC filter add dev $DEV1 ingress protocol ip flower dst_ip 1.3.3.7/32 action mirred egress mirror dev $DUMMY"
+        ],
+        "cmdUnderTest": "$TC filter add dev $DUMMY parent 1: matchall classid 1:1",
+        "scapy": [
+            {
+                "iface": "$DEV0",
+                "count": 22,
+                "packet": "Ether(type=0x800)/IP(src='10.0.0.10',dst='1.3.3.7')/TCP(sport=5000,dport=10)"
+            }
+        ],
+        "expExitCode": "0",
+        "verifyCmd": "$TC -s qdisc ls dev $DUMMY",
+        "matchPattern": "dropped 22",
+        "matchCount": "1",
+        "teardown": [
+            "$TC qdisc del dev $DUMMY handle 1: root qfq"
+        ]
     }
 ]