[IPV4]: ipip and ip_gre encapsulation bugs
Handling of ipip and ip_gre ICMP error relaying is b0rken; it accesses
8bit field + 3 reserved octets as host-endian 32bit, does comparison,
subtraction and stuffs the result back. That breaks on big-endian.
Fixed, made endian-clean.
[ Note that this effected code is permanently commented out with
and ifdef, so this error couldn't actually cause problems for
anyone. -DaveM ]
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/ipv4/ipip.c b/net/ipv4/ipip.c
index 76ab50b..0c45565 100644
--- a/net/ipv4/ipip.c
+++ b/net/ipv4/ipip.c
@@ -341,7 +341,8 @@
int code = skb->h.icmph->code;
int rel_type = 0;
int rel_code = 0;
- int rel_info = 0;
+ __be32 rel_info = 0;
+ __u32 n = 0;
struct sk_buff *skb2;
struct flowi fl;
struct rtable *rt;
@@ -354,14 +355,15 @@
default:
return 0;
case ICMP_PARAMETERPROB:
- if (skb->h.icmph->un.gateway < hlen)
+ n = ntohl(skb->h.icmph->un.gateway) >> 24;
+ if (n < hlen)
return 0;
/* So... This guy found something strange INSIDE encapsulated
packet. Well, he is fool, but what can we do ?
*/
rel_type = ICMP_PARAMETERPROB;
- rel_info = skb->h.icmph->un.gateway - hlen;
+ rel_info = htonl((n - hlen) << 24);
break;
case ICMP_DEST_UNREACH:
@@ -372,13 +374,14 @@
return 0;
case ICMP_FRAG_NEEDED:
/* And it is the only really necessary thing :-) */
- rel_info = ntohs(skb->h.icmph->un.frag.mtu);
- if (rel_info < hlen+68)
+ n = ntohs(skb->h.icmph->un.frag.mtu);
+ if (n < hlen+68)
return 0;
- rel_info -= hlen;
+ n -= hlen;
/* BSD 4.2 MORE DOES NOT EXIST IN NATURE. */
- if (rel_info > ntohs(eiph->tot_len))
+ if (n > ntohs(eiph->tot_len))
return 0;
+ rel_info = htonl(n);
break;
default:
/* All others are translated to HOST_UNREACH.
@@ -440,12 +443,11 @@
/* change mtu on this route */
if (type == ICMP_DEST_UNREACH && code == ICMP_FRAG_NEEDED) {
- if (rel_info > dst_mtu(skb2->dst)) {
+ if (n > dst_mtu(skb2->dst)) {
kfree_skb(skb2);
return 0;
}
- skb2->dst->ops->update_pmtu(skb2->dst, rel_info);
- rel_info = htonl(rel_info);
+ skb2->dst->ops->update_pmtu(skb2->dst, n);
} else if (type == ICMP_TIME_EXCEEDED) {
struct ip_tunnel *t = netdev_priv(skb2->dev);
if (t->parms.iph.ttl) {