dccp: Add check for sequence number in ICMPv6 message

This adds a sequence number check for ICMPv6 DCCP error packets, in the same
manner as it has been done for ICMPv4 in the previous patch.

Signed-off-by: Wei Yongjun <yjwei@cn.fujitsu.com>
Acked-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>

1 files changed, 9 insertions, 1 deletions

diff --git a/net/dccp/ipv6.c b/net/dccp/ipv6.c
index da509127e00c..25826b1bf685 100644
--- a/net/dccp/ipv6.c
+++ b/net/dccp/ipv6.c
@@ -89,6 +89,7 @@ static void dccp_v6_err(struct sk_buff *skb, struct inet6_skb_parm *opt,
 {
         struct ipv6hdr *hdr = (struct ipv6hdr *)skb->data;
         const struct dccp_hdr *dh = (struct dccp_hdr *)(skb->data + offset);
+        struct dccp_sock *dp;
         struct ipv6_pinfo *np;
         struct sock *sk;
         int err;
@@ -116,6 +117,14 @@ static void dccp_v6_err(struct sk_buff *skb, struct inet6_skb_parm *opt,
         if (sk->sk_state == DCCP_CLOSED)
                 goto out;
 
+        dp = dccp_sk(sk);
+        seq = dccp_hdr_seq(dh);
+        if ((1 << sk->sk_state) & ~(DCCPF_REQUESTING | DCCPF_LISTEN) &&
+            !between48(seq, dp->dccps_awl, dp->dccps_awh)) {
+                NET_INC_STATS_BH(net, LINUX_MIB_OUTOFWINDOWICMPS);
+                goto out;
+        }
+
         np = inet6_sk(sk);
 
         if (type == ICMPV6_PKT_TOOBIG) {
@@ -168,7 +177,6 @@ static void dccp_v6_err(struct sk_buff *skb, struct inet6_skb_parm *opt,
 
         icmpv6_err_convert(type, code, &err);
 
-        seq = dccp_hdr_seq(dh);
         /* Might be for an request_sock */
         switch (sk->sk_state) {
                 struct request_sock *req, **prev;