linux-kernel - [PATCH 5.7 06/20] net/sched: act_ct: fix restore the qdisc_skb

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Message-Id: <20200730074420.845160025@linuxfoundation.org>
Date:   Thu, 30 Jul 2020 10:03:56 +0200
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org, wenxu <wenxu@...oud.cn>,
        "David S. Miller" <davem@...emloft.net>
Subject: [PATCH 5.7 06/20] net/sched: act_ct: fix restore the qdisc_skb_cb after defrag

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

[ Upstream commit ae372cb1750f6c95370f92fe5f5620e0954663ba ]

The fragment packets do defrag in tcf_ct_handle_fragments
will clear the skb->cb which make the qdisc_skb_cb clear
too. So the qdsic_skb_cb should be store before defrag and
restore after that.
It also update the pkt_len after all the
fragments finish the defrag to one packet and make the
following actions counter correct.

Fixes: b57dc7c13ea9 ("net/sched: Introduce action ct")
Signed-off-by: wenxu <wenxu@...oud.cn>
Signed-off-by: David S. Miller <davem@...emloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
---
 net/sched/act_ct.c |   16 ++++++++++++++--
 1 file changed, 14 insertions(+), 2 deletions(-)

--- a/net/sched/act_ct.c
+++ b/net/sched/act_ct.c
@@ -671,9 +671,10 @@ static int tcf_ct_ipv6_is_fragment(struc
 }
 
 static int tcf_ct_handle_fragments(struct net *net, struct sk_buff *skb,
-				   u8 family, u16 zone)
+				   u8 family, u16 zone, bool *defrag)
 {
 	enum ip_conntrack_info ctinfo;
+	struct qdisc_skb_cb cb;
 	struct nf_conn *ct;
 	int err = 0;
 	bool frag;
@@ -691,6 +692,7 @@ static int tcf_ct_handle_fragments(struc
 		return err;
 
 	skb_get(skb);
+	cb = *qdisc_skb_cb(skb);
 
 	if (family == NFPROTO_IPV4) {
 		enum ip_defrag_users user = IP_DEFRAG_CONNTRACK_IN + zone;
@@ -701,6 +703,9 @@ static int tcf_ct_handle_fragments(struc
 		local_bh_enable();
 		if (err && err != -EINPROGRESS)
 			goto out_free;
+
+		if (!err)
+			*defrag = true;
 	} else { /* NFPROTO_IPV6 */
 #if IS_ENABLED(CONFIG_NF_DEFRAG_IPV6)
 		enum ip6_defrag_users user = IP6_DEFRAG_CONNTRACK_IN + zone;
@@ -709,12 +714,16 @@ static int tcf_ct_handle_fragments(struc
 		err = nf_ct_frag6_gather(net, skb, user);
 		if (err && err != -EINPROGRESS)
 			goto out_free;
+
+		if (!err)
+			*defrag = true;
 #else
 		err = -EOPNOTSUPP;
 		goto out_free;
 #endif
 	}
 
+	*qdisc_skb_cb(skb) = cb;
 	skb_clear_hash(skb);
 	skb->ignore_df = 1;
 	return err;
@@ -912,6 +921,7 @@ static int tcf_ct_act(struct sk_buff *sk
 	int nh_ofs, err, retval;
 	struct tcf_ct_params *p;
 	bool skip_add = false;
+	bool defrag = false;
 	struct nf_conn *ct;
 	u8 family;
 
@@ -942,7 +952,7 @@ static int tcf_ct_act(struct sk_buff *sk
 	 */
 	nh_ofs = skb_network_offset(skb);
 	skb_pull_rcsum(skb, nh_ofs);
-	err = tcf_ct_handle_fragments(net, skb, family, p->zone);
+	err = tcf_ct_handle_fragments(net, skb, family, p->zone, &defrag);
 	if (err == -EINPROGRESS) {
 		retval = TC_ACT_STOLEN;
 		goto out;
@@ -1010,6 +1020,8 @@ out_push:
 
 out:
 	tcf_action_update_bstats(&c->common, skb);
+	if (defrag)
+		qdisc_skb_cb(skb)->pkt_len = skb->len;
 	return retval;
 
 drop: