[PATCH 3.2 63/77] ipv6: distinguish frag queues by device for multicast and link-local packets

[Ben Hutchings <ben@decadent.org.uk>]

3.2.75-rc1 review patch.  If anyone has any objections, please let me know.

------------------

From: Michal Kubeček <mkubecek@suse.cz>

[ Upstream commit 264640fc2c5f4f913db5c73fa3eb1ead2c45e9d7 ]

If a fragmented multicast packet is received on an ethernet device which
has an active macvlan on top of it, each fragment is duplicated and
received both on the underlying device and the macvlan. If some
fragments for macvlan are processed before the whole packet for the
underlying device is reassembled, the "overlapping fragments" test in
ip6_frag_queue() discards the whole fragment queue.

To resolve this, add device ifindex to the search key and require it to
match reassembling multicast packets and packets to link-local
addresses.

Note: similar patch has been already submitted by Yoshifuji Hideaki in

  http://patchwork.ozlabs.org/patch/220979/

but got lost and forgotten for some reason.

Signed-off-by: Michal Kubecek <mkubecek@suse.cz>
Signed-off-by: David S. Miller <davem@davemloft.net>
[bwh: Backported to 3.2: adjust context]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
---
--- a/include/net/ipv6.h
+++ b/include/net/ipv6.h
@@ -382,6 +382,7 @@ struct ip6_create_arg {
 	u32 user;
 	const struct in6_addr *src;
 	const struct in6_addr *dst;
+	int iif;
 };
 
 void ip6_frag_init(struct inet_frag_queue *q, void *a);
--- a/net/ipv6/netfilter/nf_conntrack_reasm.c
+++ b/net/ipv6/netfilter/nf_conntrack_reasm.c
@@ -162,7 +162,7 @@ out:
 /* Creation primitives. */
 
 static __inline__ struct nf_ct_frag6_queue *
-fq_find(__be32 id, u32 user, struct in6_addr *src, struct in6_addr *dst)
+fq_find(__be32 id, u32 user, struct in6_addr *src, struct in6_addr *dst, int iif)
 {
 	struct inet_frag_queue *q;
 	struct ip6_create_arg arg;
@@ -172,6 +172,7 @@ fq_find(__be32 id, u32 user, struct in6_
 	arg.user = user;
 	arg.src = src;
 	arg.dst = dst;
+	arg.iif = iif;
 
 	read_lock_bh(&nf_frags.lock);
 	hash = inet6_hash_frag(id, src, dst, nf_frags.rnd);
@@ -558,7 +559,8 @@ struct sk_buff *nf_ct_frag6_gather(struc
 	if (atomic_read(&nf_init_frags.mem) > nf_init_frags.high_thresh)
 		nf_ct_frag6_evictor();
 
-	fq = fq_find(fhdr->identification, user, &hdr->saddr, &hdr->daddr);
+	fq = fq_find(fhdr->identification, user, &hdr->saddr, &hdr->daddr,
+		     skb->dev ? skb->dev->ifindex : 0);
 	if (fq == NULL) {
 		pr_debug("Can't find and can't create new queue\n");
 		goto ret_orig;
--- a/net/ipv6/reassembly.c
+++ b/net/ipv6/reassembly.c
@@ -144,8 +144,11 @@ int ip6_frag_match(struct inet_frag_queu
 
 	fq = container_of(q, struct frag_queue, q);
 	return (fq->id == arg->id && fq->user == arg->user &&
-			ipv6_addr_equal(&fq->saddr, arg->src) &&
-			ipv6_addr_equal(&fq->daddr, arg->dst));
+		ipv6_addr_equal(&fq->saddr, arg->src) &&
+		ipv6_addr_equal(&fq->daddr, arg->dst) &&
+		(arg->iif == fq->iif ||
+		 !(ipv6_addr_type(arg->dst) & (IPV6_ADDR_MULTICAST |
+					       IPV6_ADDR_LINKLOCAL))));
 }
 EXPORT_SYMBOL(ip6_frag_match);
 
@@ -228,7 +231,8 @@ out:
 }
 
 static __inline__ struct frag_queue *
-fq_find(struct net *net, __be32 id, const struct in6_addr *src, const struct in6_addr *dst)
+fq_find(struct net *net, __be32 id, const struct in6_addr *src,
+	const struct in6_addr *dst, int iif)
 {
 	struct inet_frag_queue *q;
 	struct ip6_create_arg arg;
@@ -238,6 +242,7 @@ fq_find(struct net *net, __be32 id, cons
 	arg.user = IP6_DEFRAG_LOCAL_DELIVER;
 	arg.src = src;
 	arg.dst = dst;
+	arg.iif = iif;
 
 	read_lock(&ip6_frags.lock);
 	hash = inet6_hash_frag(id, src, dst, ip6_frags.rnd);
@@ -583,7 +588,8 @@ static int ipv6_frag_rcv(struct sk_buff
 	if (atomic_read(&net->ipv6.frags.mem) > net->ipv6.frags.high_thresh)
 		ip6_evictor(net, ip6_dst_idev(skb_dst(skb)));
 
-	fq = fq_find(net, fhdr->identification, &hdr->saddr, &hdr->daddr);
+	fq = fq_find(net, fhdr->identification, &hdr->saddr, &hdr->daddr,
+		     skb->dev ? skb->dev->ifindex : 0);
 	if (fq != NULL) {
 		int ret;