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Diffstat (limited to 'net/ipv6/sit.c')
-rw-r--r--net/ipv6/sit.c112
1 files changed, 81 insertions, 31 deletions
diff --git a/net/ipv6/sit.c b/net/ipv6/sit.c
index a3437a4cd07..19269453a8e 100644
--- a/net/ipv6/sit.c
+++ b/net/ipv6/sit.c
@@ -566,6 +566,70 @@ static inline bool is_spoofed_6rd(struct ip_tunnel *tunnel, const __be32 v4addr,
return false;
}
+/* Checks if an address matches an address on the tunnel interface.
+ * Used to detect the NAT of proto 41 packets and let them pass spoofing test.
+ * Long story:
+ * This function is called after we considered the packet as spoofed
+ * in is_spoofed_6rd.
+ * We may have a router that is doing NAT for proto 41 packets
+ * for an internal station. Destination a.a.a.a/PREFIX:bbbb:bbbb
+ * will be translated to n.n.n.n/PREFIX:bbbb:bbbb. And is_spoofed_6rd
+ * function will return true, dropping the packet.
+ * But, we can still check if is spoofed against the IP
+ * addresses associated with the interface.
+ */
+static bool only_dnatted(const struct ip_tunnel *tunnel,
+ const struct in6_addr *v6dst)
+{
+ int prefix_len;
+
+#ifdef CONFIG_IPV6_SIT_6RD
+ prefix_len = tunnel->ip6rd.prefixlen + 32
+ - tunnel->ip6rd.relay_prefixlen;
+#else
+ prefix_len = 48;
+#endif
+ return ipv6_chk_custom_prefix(v6dst, prefix_len, tunnel->dev);
+}
+
+/* Returns true if a packet is spoofed */
+static bool packet_is_spoofed(struct sk_buff *skb,
+ const struct iphdr *iph,
+ struct ip_tunnel *tunnel)
+{
+ const struct ipv6hdr *ipv6h;
+
+ if (tunnel->dev->priv_flags & IFF_ISATAP) {
+ if (!isatap_chksrc(skb, iph, tunnel))
+ return true;
+
+ return false;
+ }
+
+ if (tunnel->dev->flags & IFF_POINTOPOINT)
+ return false;
+
+ ipv6h = ipv6_hdr(skb);
+
+ if (unlikely(is_spoofed_6rd(tunnel, iph->saddr, &ipv6h->saddr))) {
+ net_warn_ratelimited("Src spoofed %pI4/%pI6c -> %pI4/%pI6c\n",
+ &iph->saddr, &ipv6h->saddr,
+ &iph->daddr, &ipv6h->daddr);
+ return true;
+ }
+
+ if (likely(!is_spoofed_6rd(tunnel, iph->daddr, &ipv6h->daddr)))
+ return false;
+
+ if (only_dnatted(tunnel, &ipv6h->daddr))
+ return false;
+
+ net_warn_ratelimited("Dst spoofed %pI4/%pI6c -> %pI4/%pI6c\n",
+ &iph->saddr, &ipv6h->saddr,
+ &iph->daddr, &ipv6h->daddr);
+ return true;
+}
+
static int ipip6_rcv(struct sk_buff *skb)
{
const struct iphdr *iph = ip_hdr(skb);
@@ -581,29 +645,17 @@ static int ipip6_rcv(struct sk_buff *skb)
tunnel->parms.iph.protocol != 0)
goto out;
- secpath_reset(skb);
skb->mac_header = skb->network_header;
skb_reset_network_header(skb);
IPCB(skb)->flags = 0;
skb->protocol = htons(ETH_P_IPV6);
- skb->pkt_type = PACKET_HOST;
- if (tunnel->dev->priv_flags & IFF_ISATAP) {
- if (!isatap_chksrc(skb, iph, tunnel)) {
- tunnel->dev->stats.rx_errors++;
- goto out;
- }
- } else if (!(tunnel->dev->flags&IFF_POINTOPOINT)) {
- if (is_spoofed_6rd(tunnel, iph->saddr,
- &ipv6_hdr(skb)->saddr) ||
- is_spoofed_6rd(tunnel, iph->daddr,
- &ipv6_hdr(skb)->daddr)) {
- tunnel->dev->stats.rx_errors++;
- goto out;
- }
+ if (packet_is_spoofed(skb, iph, tunnel)) {
+ tunnel->dev->stats.rx_errors++;
+ goto out;
}
- __skb_tunnel_rx(skb, tunnel->dev);
+ __skb_tunnel_rx(skb, tunnel->dev, tunnel->net);
err = IP_ECN_decapsulate(iph, skb);
if (unlikely(err)) {
@@ -621,8 +673,6 @@ static int ipip6_rcv(struct sk_buff *skb)
tstats->rx_packets++;
tstats->rx_bytes += skb->len;
- if (tunnel->net != dev_net(tunnel->dev))
- skb_scrub_packet(skb);
netif_rx(skb);
return 0;
@@ -645,11 +695,7 @@ static int ipip_rcv(struct sk_buff *skb)
const struct iphdr *iph;
struct ip_tunnel *tunnel;
- if (iptunnel_pull_header(skb, 0, tpi.proto))
- goto drop;
-
iph = ip_hdr(skb);
-
tunnel = ipip6_tunnel_lookup(dev_net(skb->dev), skb->dev,
iph->saddr, iph->daddr);
if (tunnel != NULL) {
@@ -659,6 +705,8 @@ static int ipip_rcv(struct sk_buff *skb)
if (!xfrm4_policy_check(NULL, XFRM_POLICY_IN, skb))
goto drop;
+ if (iptunnel_pull_header(skb, 0, tpi.proto))
+ goto drop;
return ip_tunnel_rcv(tunnel, skb, &tpi, log_ecn_error);
}
@@ -754,7 +802,7 @@ static netdev_tx_t ipip6_tunnel_xmit(struct sk_buff *skb,
neigh = dst_neigh_lookup(skb_dst(skb), &iph6->daddr);
if (neigh == NULL) {
- net_dbg_ratelimited("sit: nexthop == NULL\n");
+ net_dbg_ratelimited("nexthop == NULL\n");
goto tx_error;
}
@@ -783,7 +831,7 @@ static netdev_tx_t ipip6_tunnel_xmit(struct sk_buff *skb,
neigh = dst_neigh_lookup(skb_dst(skb), &iph6->daddr);
if (neigh == NULL) {
- net_dbg_ratelimited("sit: nexthop == NULL\n");
+ net_dbg_ratelimited("nexthop == NULL\n");
goto tx_error;
}
@@ -860,9 +908,6 @@ static netdev_tx_t ipip6_tunnel_xmit(struct sk_buff *skb,
tunnel->err_count = 0;
}
- if (tunnel->net != dev_net(dev))
- skb_scrub_packet(skb);
-
/*
* Okay, now see if we can stuff it in the buffer as-is.
*/
@@ -888,8 +933,13 @@ static netdev_tx_t ipip6_tunnel_xmit(struct sk_buff *skb,
ttl = iph6->hop_limit;
tos = INET_ECN_encapsulate(tos, ipv6_get_dsfield(iph6));
- err = iptunnel_xmit(dev_net(dev), rt, skb, fl4.saddr, fl4.daddr,
- IPPROTO_IPV6, tos, ttl, df);
+ if (likely(!skb->encapsulation)) {
+ skb_reset_inner_headers(skb);
+ skb->encapsulation = 1;
+ }
+
+ err = iptunnel_xmit(rt, skb, fl4.saddr, fl4.daddr, IPPROTO_IPV6, tos,
+ ttl, df, !net_eq(tunnel->net, dev_net(dev)));
iptunnel_xmit_stats(err, &dev->stats, dev->tstats);
return NETDEV_TX_OK;
@@ -1589,7 +1639,7 @@ static void __net_exit sit_destroy_tunnels(struct sit_net *sitn, struct list_hea
/* If dev is in the same netns, it has already
* been added to the list by the previous loop.
*/
- if (dev_net(t->dev) != net)
+ if (!net_eq(dev_net(t->dev), net))
unregister_netdevice_queue(t->dev,
head);
t = rtnl_dereference(t->next);
@@ -1616,6 +1666,7 @@ static int __net_init sit_init_net(struct net *net)
goto err_alloc_dev;
}
dev_net_set(sitn->fb_tunnel_dev, net);
+ sitn->fb_tunnel_dev->rtnl_link_ops = &sit_link_ops;
/* FB netdevice is special: we have one, and only one per netns.
* Allowing to move it to another netns is clearly unsafe.
*/
@@ -1650,7 +1701,6 @@ static void __net_exit sit_exit_net(struct net *net)
rtnl_lock();
sit_destroy_tunnels(sitn, &list);
- unregister_netdevice_queue(sitn->fb_tunnel_dev, &list);
unregister_netdevice_many(&list);
rtnl_unlock();
}
generated by cgit v1.2.3-70-g09d2 (git 2.46.0) at 2025-04-09 22:23:00 +0000