[IPV6]: Disallow RH0 by default.

A security issue is emerging.  Disallow Routing Header Type 0 by default
as we have been doing for IPv4.
Note: We allow RH2 by default because it is harmless.

Signed-off-by: YOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 34 insertions, 6 deletions

diff --git a/net/ipv6/exthdrs.c b/net/ipv6/exthdrs.c
index 28e0c6568272..6ed6a8cd6a68 100644
--- a/net/ipv6/exthdrs.c
+++ b/net/ipv6/exthdrs.c
@@ -362,10 +362,27 @@ static int ipv6_rthdr_rcv(struct sk_buff **skbp)
         struct inet6_skb_parm *opt = IP6CB(skb);
         struct in6_addr *addr = NULL;
         struct in6_addr daddr;
+        struct inet6_dev *idev;
         int n, i;
-
         struct ipv6_rt_hdr *hdr;
         struct rt0_hdr *rthdr;
+        int accept_source_route = ipv6_devconf.accept_source_route;
+
+        if (accept_source_route < 0 ||
+            ((idev = in6_dev_get(skb->dev)) == NULL)) {
+                kfree_skb(skb);
+                return -1;
+        }
+        if (idev->cnf.accept_source_route < 0) {
+                in6_dev_put(idev);
+                kfree_skb(skb);
+                return -1;
+        }
+
+        if (accept_source_route > idev->cnf.accept_source_route)
+                accept_source_route = idev->cnf.accept_source_route;
+
+        in6_dev_put(idev);
 
         if (!pskb_may_pull(skb, (skb->h.raw-skb->data)+8) ||
             !pskb_may_pull(skb, (skb->h.raw-skb->data)+((skb->h.raw[1]+1)<<3))) {
@@ -377,6 +394,22 @@ static int ipv6_rthdr_rcv(struct sk_buff **skbp)
 
         hdr = (struct ipv6_rt_hdr *) skb->h.raw;
 
+        switch (hdr->type) {
+#ifdef CONFIG_IPV6_MIP6
+                break;
+#endif
+        case IPV6_SRCRT_TYPE_0:
+                if (accept_source_route <= 0)
+                        break;
+                kfree_skb(skb);
+                return -1;
+        default:
+                IP6_INC_STATS_BH(ip6_dst_idev(skb->dst),
+                                 IPSTATS_MIB_INHDRERRORS);
+                icmpv6_param_prob(skb, ICMPV6_HDR_FIELD, (&hdr->type) - skb->nh.raw);
+                return -1;
+        }
+
         if (ipv6_addr_is_multicast(&skb->nh.ipv6h->daddr) ||
             skb->pkt_type != PACKET_HOST) {
                 IP6_INC_STATS_BH(ip6_dst_idev(skb->dst),
@@ -434,11 +467,6 @@ looped_back:
                 }
                 break;
 #endif
-        default:
-                IP6_INC_STATS_BH(ip6_dst_idev(skb->dst),
-                                 IPSTATS_MIB_INHDRERRORS);
-                icmpv6_param_prob(skb, ICMPV6_HDR_FIELD, (&hdr->type) - skb->nh.raw);
-                return -1;
         }
 
         /*