[PATCH net] dccp: do not use ipv6 header for ipv4 flow

[PATCH net] dccp: do not use ipv6 header for ipv4 flow

[Eric Dumazet]

When a dual stack dccp listener accepts an ipv4 flow,
it should not attempt to use an ipv6 header or
inet6_iif() helper.

Fixes: 3df80d9320bc ("[DCCP]: Introduce DCCPv6")
Signed-off-by: Eric Dumazet <edumazet@google.com>
---
 net/dccp/ipv6.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/net/dccp/ipv6.c b/net/dccp/ipv6.c
index d5740bad5b1811cd42e44fb3b0da6edabbf18095..57d84e9b7b6fc820a4616e3ac326633f14e2fd95 100644
--- a/net/dccp/ipv6.c
+++ b/net/dccp/ipv6.c
@@ -436,8 +436,8 @@ static struct sock *dccp_v6_request_recv_sock(const struct sock *sk,
 		newnp->ipv6_mc_list = NULL;
 		newnp->ipv6_ac_list = NULL;
 		newnp->ipv6_fl_list = NULL;
-		newnp->mcast_oif   = inet6_iif(skb);
-		newnp->mcast_hops  = ipv6_hdr(skb)->hop_limit;
+		newnp->mcast_oif   = inet_iif(skb);
+		newnp->mcast_hops  = ip_hdr(skb)->ttl;
 
 		/*
 		 * No need to charge this sock to the relevant IPv6 refcnt debug socks count
-- 
2.21.0.225.g810b269d1ac-goog

Re: [PATCH net] dccp: do not use ipv6 header for ipv4 flow

[David Miller]

From: Eric Dumazet <edumazet@google.com>
Date: Tue, 19 Mar 2019 05:46:18 -0700

> When a dual stack dccp listener accepts an ipv4 flow,
> it should not attempt to use an ipv6 header or
> inet6_iif() helper.
> 
> Fixes: 3df80d9320bc ("[DCCP]: Introduce DCCPv6")
> Signed-off-by: Eric Dumazet <edumazet@google.com>

Applied and queued up for -stable.