[PATCH net v2] net/sched: cls_flower: Reject invalid ct_state flags rules

[wenxu]

From: wenxu <we...@ucloud.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 <we...@ucloud.cn>
---
 include/uapi/linux/pkt_cls.h |  7 +++++++
 net/sched/cls_flower.c       | 30 ++++++++++++++++++++++++++++++
 2 files changed, 37 insertions(+)

diff --git a/include/uapi/linux/pkt_cls.h b/include/uapi/linux/pkt_cls.h
index ee95f42..77df582 100644
--- a/include/uapi/linux/pkt_cls.h
+++ b/include/uapi/linux/pkt_cls.h
@@ -591,8 +591,15 @@ 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,
 };
 
+#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)
+
 enum {
        TCA_FLOWER_KEY_ENC_OPTS_UNSPEC,
        TCA_FLOWER_KEY_ENC_OPTS_GENEVE, /* Nested
diff --git a/net/sched/cls_flower.c b/net/sched/cls_flower.c
index 84f9325..1cfdbd4 100644
--- a/net/sched/cls_flower.c
+++ b/net/sched/cls_flower.c
@@ -1390,12 +1390,37 @@ 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 netlink_ext_ack *extack)
+{
+       if (state & ~TCA_FLOWER_KEY_CT_FLAGS_MASK) {
+               NL_SET_ERR_MSG_MOD(extack, "unsupported ct_state flags");
+               return -EINVAL;
+       }
+
+       if (state && !(state & TCA_FLOWER_KEY_CT_FLAGS_TRACKED)) {
+               NL_SET_ERR_MSG_MOD(extack,
+                                  "ct_state trk unset, no other flag are set");
+               return -EINVAL;
+       }
+
+       if (state & TCA_FLOWER_KEY_CT_FLAGS_NEW &&
+           state & TCA_FLOWER_KEY_CT_FLAGS_ESTABLISHED) {
+               NL_SET_ERR_MSG_MOD(extack,
+                                  "ct_state new and est are 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 +1428,11 @@ 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, extack);
+               if (err)
+                       return err;
+
        }
        if (tb[TCA_FLOWER_KEY_CT_ZONE]) {
                if (!IS_ENABLED(CONFIG_NF_CONNTRACK_ZONES)) {
-- 
1.8.3.1