[RFC/PATCH net-next v2 5/5] flow_offload: validate flags of filter and actions

[Simon Horman <simon.horman@corigine.com>]

From: Baowen Zheng <baowen.zheng@corigine.com>

Add process to validate flags of filter and actions when adding
a tc filter.

We need to prevent adding filter with flags conflicts with its actions.

Signed-off-by: Baowen Zheng <baowen.zheng@corigine.com>
Signed-off-by: Louis Peens <louis.peens@corigine.com>
Signed-off-by: Simon Horman <simon.horman@corigine.com>
---
 include/net/pkt_cls.h    | 32 ++++++++++++++++++++++++++++++++
 net/sched/cls_flower.c   |  5 +++++
 net/sched/cls_matchall.c |  6 ++++++
 net/sched/cls_u32.c      | 11 +++++++++++
 4 files changed, 54 insertions(+)

diff --git a/include/net/pkt_cls.h b/include/net/pkt_cls.h
index 5c394f04feb5..2d51bed434d2 100644
--- a/include/net/pkt_cls.h
+++ b/include/net/pkt_cls.h
@@ -735,6 +735,38 @@ static inline bool tc_in_hw(u32 flags)
 	return (flags & TCA_CLS_FLAGS_IN_HW) ? true : false;
 }
 
+/**
+ * tcf_exts_validate_actions - check if exts actions flags are compatible with
+ * tc filter flags
+ * @exts: tc filter extensions handle
+ * @flags: tc filter flags
+ *
+ * Returns true if exts actions flags are compatible with tc filter flags
+ */
+static inline bool
+tcf_exts_validate_actions(const struct tcf_exts *exts, u32 flags)
+{
+#ifdef CONFIG_NET_CLS_ACT
+	bool skip_sw = tc_skip_sw(flags);
+	bool skip_hw = tc_skip_hw(flags);
+	int i;
+
+	if (!(skip_sw | skip_hw))
+		return true;
+
+	for (i = 0; i < exts->nr_actions; i++) {
+		struct tc_action *a = exts->actions[i];
+
+		if ((skip_sw && tc_act_skip_hw(a->tcfa_flags)) ||
+		    (skip_hw && tc_act_skip_sw(a->tcfa_flags)))
+			return false;
+	}
+	return true;
+#else
+	return true;
+#endif
+}
+
 static inline void
 tc_cls_common_offload_init(struct flow_cls_common_offload *cls_common,
 			   const struct tcf_proto *tp, u32 flags,
diff --git a/net/sched/cls_flower.c b/net/sched/cls_flower.c
index eb6345a027e1..15e439349124 100644
--- a/net/sched/cls_flower.c
+++ b/net/sched/cls_flower.c
@@ -2039,6 +2039,11 @@ static int fl_change(struct net *net, struct sk_buff *in_skb,
 	if (err)
 		goto errout;
 
+	if (!tcf_exts_validate_actions(&fnew->exts, fnew->flags)) {
+		err = -EINVAL;
+		goto errout;
+	}
+
 	err = fl_check_assign_mask(head, fnew, fold, mask);
 	if (err)
 		goto errout;
diff --git a/net/sched/cls_matchall.c b/net/sched/cls_matchall.c
index 24f0046ce0b3..89dbbb9f31e8 100644
--- a/net/sched/cls_matchall.c
+++ b/net/sched/cls_matchall.c
@@ -231,6 +231,11 @@ static int mall_change(struct net *net, struct sk_buff *in_skb,
 	if (err)
 		goto err_set_parms;
 
+	if (!tcf_exts_validate_actions(&new->exts, new->flags)) {
+		err = -EINVAL;
+		goto err_validate;
+	}
+
 	if (!tc_skip_hw(new->flags)) {
 		err = mall_replace_hw_filter(tp, new, (unsigned long)new,
 					     extack);
@@ -246,6 +251,7 @@ static int mall_change(struct net *net, struct sk_buff *in_skb,
 	return 0;
 
 err_replace_hw_filter:
+err_validate:
 err_set_parms:
 	free_percpu(new->pf);
 err_alloc_percpu:
diff --git a/net/sched/cls_u32.c b/net/sched/cls_u32.c
index 4272814487f0..8bc19af18e4a 100644
--- a/net/sched/cls_u32.c
+++ b/net/sched/cls_u32.c
@@ -902,6 +902,11 @@ static int u32_change(struct net *net, struct sk_buff *in_skb,
 			return err;
 		}
 
+		if (!tcf_exts_validate_actions(&new->exts, flags)) {
+			u32_destroy_key(new, false);
+			return -EINVAL;
+		}
+
 		err = u32_replace_hw_knode(tp, new, flags, extack);
 		if (err) {
 			u32_destroy_key(new, false);
@@ -1066,6 +1071,11 @@ static int u32_change(struct net *net, struct sk_buff *in_skb,
 		struct tc_u_knode __rcu **ins;
 		struct tc_u_knode *pins;
 
+		if (!tcf_exts_validate_actions(&n->exts, n->flags)) {
+			err = -EINVAL;
+			goto err_validate;
+		}
+
 		err = u32_replace_hw_knode(tp, n, flags, extack);
 		if (err)
 			goto errhw;
@@ -1086,6 +1096,7 @@ static int u32_change(struct net *net, struct sk_buff *in_skb,
 		return 0;
 	}
 
+err_validate:
 errhw:
 #ifdef CONFIG_CLS_U32_MARK
 	free_percpu(n->pcpu_success);
-- 
2.20.1