netdev - [PATCH net v5] net/sched: cls_flower: Reject invalid ct

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Date:   Tue,  9 Feb 2021 14:37:49 +0800
From:   wenxu@...oud.cn
To:     jhs@...atatu.com, mleitner@...hat.com, kuba@...nel.org
Cc:     netdev@...r.kernel.org
Subject: [PATCH net v5] net/sched: cls_flower: Reject invalid ct_state flags rules

From: wenxu <wenxu@...oud.cn>

Reject the unsupported and invalid ct_state flags of cls flower rules.

Fixes: e0ace68af2ac ("net/sched: cls_flower: Add matching on conntrack info")
Signed-off-by: wenxu <wenxu@...oud.cn>
---
 include/uapi/linux/pkt_cls.h |  2 ++
 net/sched/cls_flower.c       | 39 +++++++++++++++++++++++++++++++++++++--
 2 files changed, 39 insertions(+), 2 deletions(-)

diff --git a/include/uapi/linux/pkt_cls.h b/include/uapi/linux/pkt_cls.h
index ee95f42..88f4bf0 100644
--- a/include/uapi/linux/pkt_cls.h
+++ b/include/uapi/linux/pkt_cls.h
@@ -591,6 +591,8 @@ enum {
 	TCA_FLOWER_KEY_CT_FLAGS_ESTABLISHED = 1 << 1, /* Part of an existing connection. */
 	TCA_FLOWER_KEY_CT_FLAGS_RELATED = 1 << 2, /* Related to an established connection. */
 	TCA_FLOWER_KEY_CT_FLAGS_TRACKED = 1 << 3, /* Conntrack has occurred. */
+
+	__TCA_FLOWER_KEY_CT_FLAGS_MAX,
 };
 
 enum {
diff --git a/net/sched/cls_flower.c b/net/sched/cls_flower.c
index 84f9325..46c1b3e 100644
--- a/net/sched/cls_flower.c
+++ b/net/sched/cls_flower.c
@@ -30,6 +30,11 @@
 
 #include <uapi/linux/netfilter/nf_conntrack_common.h>
 
+#define TCA_FLOWER_KEY_CT_FLAGS_MAX \
+		((__TCA_FLOWER_KEY_CT_FLAGS_MAX - 1) << 1)
+#define TCA_FLOWER_KEY_CT_FLAGS_MASK \
+		(TCA_FLOWER_KEY_CT_FLAGS_MAX - 1)
+
 struct fl_flow_key {
 	struct flow_dissector_key_meta meta;
 	struct flow_dissector_key_control control;
@@ -686,8 +691,10 @@ static void *fl_get(struct tcf_proto *tp, u32 handle)
 	[TCA_FLOWER_KEY_ENC_IP_TTL_MASK] = { .type = NLA_U8 },
 	[TCA_FLOWER_KEY_ENC_OPTS]	= { .type = NLA_NESTED },
 	[TCA_FLOWER_KEY_ENC_OPTS_MASK]	= { .type = NLA_NESTED },
-	[TCA_FLOWER_KEY_CT_STATE]	= { .type = NLA_U16 },
-	[TCA_FLOWER_KEY_CT_STATE_MASK]	= { .type = NLA_U16 },
+	[TCA_FLOWER_KEY_CT_STATE]	=
+		NLA_POLICY_MASK(NLA_U16, TCA_FLOWER_KEY_CT_FLAGS_MASK),
+	[TCA_FLOWER_KEY_CT_STATE_MASK]	=
+		NLA_POLICY_MASK(NLA_U16, TCA_FLOWER_KEY_CT_FLAGS_MASK),
 	[TCA_FLOWER_KEY_CT_ZONE]	= { .type = NLA_U16 },
 	[TCA_FLOWER_KEY_CT_ZONE_MASK]	= { .type = NLA_U16 },
 	[TCA_FLOWER_KEY_CT_MARK]	= { .type = NLA_U32 },
@@ -1390,12 +1397,33 @@ static int fl_set_enc_opt(struct nlattr **tb, struct fl_flow_key *key,
 	return 0;
 }
 
+static int fl_validate_ct_state(u16 state, struct nlattr *tb,
+				struct netlink_ext_ack *extack)
+{
+	if (state && !(state & TCA_FLOWER_KEY_CT_FLAGS_TRACKED)) {
+		NL_SET_ERR_MSG_ATTR(extack, tb,
+				    "no trk, so no other flag can be set");
+		return -EINVAL;
+	}
+
+	if (state & TCA_FLOWER_KEY_CT_FLAGS_NEW &&
+	    state & TCA_FLOWER_KEY_CT_FLAGS_ESTABLISHED) {
+		NL_SET_ERR_MSG_ATTR(extack, tb,
+				    "new and est are mutually exclusive");
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
 static int fl_set_key_ct(struct nlattr **tb,
 			 struct flow_dissector_key_ct *key,
 			 struct flow_dissector_key_ct *mask,
 			 struct netlink_ext_ack *extack)
 {
 	if (tb[TCA_FLOWER_KEY_CT_STATE]) {
+		int err;
+
 		if (!IS_ENABLED(CONFIG_NF_CONNTRACK)) {
 			NL_SET_ERR_MSG(extack, "Conntrack isn't enabled");
 			return -EOPNOTSUPP;
@@ -1403,6 +1431,13 @@ static int fl_set_key_ct(struct nlattr **tb,
 		fl_set_key_val(tb, &key->ct_state, TCA_FLOWER_KEY_CT_STATE,
 			       &mask->ct_state, TCA_FLOWER_KEY_CT_STATE_MASK,
 			       sizeof(key->ct_state));
+
+		err = fl_validate_ct_state(mask->ct_state,
+					   tb[TCA_FLOWER_KEY_CT_STATE_MASK],
+					   extack);
+		if (err)
+			return err;
+
 	}
 	if (tb[TCA_FLOWER_KEY_CT_ZONE]) {
 		if (!IS_ENABLED(CONFIG_NF_CONNTRACK_ZONES)) {
-- 
1.8.3.1