[PATCH net-next v2 3/4] net: sched: em_ipt: keep the user-specified nfproto and use it

[Nikolay Aleksandrov <nikolay@cumulusnetworks.com>]

For NFPROTO_UNSPEC xt_matches there's no way to restrict the matching to a
specific family, in order to do so we record the user-specified family
and later enforce it while doing the match.

v2: adjust changes to missing patch, was patch 04 in v1

Signed-off-by: Nikolay Aleksandrov <nikolay@cumulusnetworks.com>
---
 net/sched/em_ipt.c | 17 +++++++++++++++--
 1 file changed, 15 insertions(+), 2 deletions(-)

diff --git a/net/sched/em_ipt.c b/net/sched/em_ipt.c
index fd7f5b288c31..ce91f3cea0bd 100644
--- a/net/sched/em_ipt.c
+++ b/net/sched/em_ipt.c
@@ -21,6 +21,7 @@
 struct em_ipt_match {
 	const struct xt_match *match;
 	u32 hook;
+	u8 nfproto;
 	u8 match_data[0] __aligned(8);
 };
 
@@ -115,6 +116,7 @@ static int em_ipt_change(struct net *net, void *data, int data_len,
 	struct em_ipt_match *im = NULL;
 	struct xt_match *match;
 	int mdata_len, ret;
+	u8 nfproto;
 
 	ret = nla_parse_deprecated(tb, TCA_EM_IPT_MAX, data, data_len,
 				   em_ipt_policy, NULL);
@@ -125,6 +127,16 @@ static int em_ipt_change(struct net *net, void *data, int data_len,
 	    !tb[TCA_EM_IPT_MATCH_DATA] || !tb[TCA_EM_IPT_NFPROTO])
 		return -EINVAL;
 
+	nfproto = nla_get_u8(tb[TCA_EM_IPT_NFPROTO]);
+	switch (nfproto) {
+	case NFPROTO_IPV4:
+	case NFPROTO_IPV6:
+	case NFPROTO_UNSPEC:
+		break;
+	default:
+		return -EINVAL;
+	}
+
 	match = get_xt_match(tb);
 	if (IS_ERR(match)) {
 		pr_err("unable to load match\n");
@@ -140,6 +152,7 @@ static int em_ipt_change(struct net *net, void *data, int data_len,
 
 	im->match = match;
 	im->hook = nla_get_u32(tb[TCA_EM_IPT_HOOK]);
+	im->nfproto = nfproto;
 	nla_memcpy(im->match_data, tb[TCA_EM_IPT_MATCH_DATA], mdata_len);
 
 	ret = check_match(net, im, mdata_len);
@@ -182,8 +195,8 @@ static int em_ipt_match(struct sk_buff *skb, struct tcf_ematch *em,
 	const struct em_ipt_match *im = (const void *)em->data;
 	struct xt_action_param acpar = {};
 	struct net_device *indev = NULL;
-	u8 nfproto = im->match->family;
 	struct nf_hook_state state;
+	u8 nfproto = im->nfproto;
 	int ret;
 
 	switch (tc_skb_protocol(skb)) {
@@ -231,7 +244,7 @@ static int em_ipt_dump(struct sk_buff *skb, struct tcf_ematch *em)
 		return -EMSGSIZE;
 	if (nla_put_u8(skb, TCA_EM_IPT_MATCH_REVISION, im->match->revision) < 0)
 		return -EMSGSIZE;
-	if (nla_put_u8(skb, TCA_EM_IPT_NFPROTO, im->match->family) < 0)
+	if (nla_put_u8(skb, TCA_EM_IPT_NFPROTO, im->nfproto) < 0)
 		return -EMSGSIZE;
 	if (nla_put(skb, TCA_EM_IPT_MATCH_DATA,
 		    im->match->usersize ?: im->match->matchsize,
-- 
2.20.1