diff options
| -rw-r--r-- | net/ipv4/netfilter/nf_reject_ipv4.c | 25 | ||||
| -rw-r--r-- | net/ipv6/netfilter/nf_reject_ipv6.c | 30 |
2 files changed, 55 insertions, 0 deletions
diff --git a/net/ipv4/netfilter/nf_reject_ipv4.c b/net/ipv4/netfilter/nf_reject_ipv4.c index 05631abe3f0d..fae4aa4a5f09 100644 --- a/net/ipv4/netfilter/nf_reject_ipv4.c +++ b/net/ipv4/netfilter/nf_reject_ipv4.c @@ -80,6 +80,27 @@ struct sk_buff *nf_reject_skb_v4_tcp_reset(struct net *net, } EXPORT_SYMBOL_GPL(nf_reject_skb_v4_tcp_reset); +static bool nf_skb_is_icmp_unreach(const struct sk_buff *skb) +{ + const struct iphdr *iph = ip_hdr(skb); + u8 *tp, _type; + int thoff; + + if (iph->protocol != IPPROTO_ICMP) + return false; + + thoff = skb_network_offset(skb) + sizeof(*iph); + + tp = skb_header_pointer(skb, + thoff + offsetof(struct icmphdr, type), + sizeof(_type), &_type); + + if (!tp) + return false; + + return *tp == ICMP_DEST_UNREACH; +} + struct sk_buff *nf_reject_skb_v4_unreach(struct net *net, struct sk_buff *oldskb, const struct net_device *dev, @@ -100,6 +121,10 @@ struct sk_buff *nf_reject_skb_v4_unreach(struct net *net, if (ip_hdr(oldskb)->frag_off & htons(IP_OFFSET)) return NULL; + /* don't reply to ICMP_DEST_UNREACH with ICMP_DEST_UNREACH. */ + if (nf_skb_is_icmp_unreach(oldskb)) + return NULL; + /* RFC says return as much as we can without exceeding 576 bytes. */ len = min_t(unsigned int, 536, oldskb->len); diff --git a/net/ipv6/netfilter/nf_reject_ipv6.c b/net/ipv6/netfilter/nf_reject_ipv6.c index 6b022449f867..ef5b7e85cffa 100644 --- a/net/ipv6/netfilter/nf_reject_ipv6.c +++ b/net/ipv6/netfilter/nf_reject_ipv6.c @@ -104,6 +104,32 @@ struct sk_buff *nf_reject_skb_v6_tcp_reset(struct net *net, } EXPORT_SYMBOL_GPL(nf_reject_skb_v6_tcp_reset); +static bool nf_skb_is_icmp6_unreach(const struct sk_buff *skb) +{ + const struct ipv6hdr *ip6h = ipv6_hdr(skb); + u8 proto = ip6h->nexthdr; + u8 _type, *tp; + int thoff; + __be16 fo; + + thoff = ipv6_skip_exthdr(skb, ((u8 *)(ip6h + 1) - skb->data), &proto, &fo); + + if (thoff < 0 || thoff >= skb->len || fo != 0) + return false; + + if (proto != IPPROTO_ICMPV6) + return false; + + tp = skb_header_pointer(skb, + thoff + offsetof(struct icmp6hdr, icmp6_type), + sizeof(_type), &_type); + + if (!tp) + return false; + + return *tp == ICMPV6_DEST_UNREACH; +} + struct sk_buff *nf_reject_skb_v6_unreach(struct net *net, struct sk_buff *oldskb, const struct net_device *dev, @@ -117,6 +143,10 @@ struct sk_buff *nf_reject_skb_v6_unreach(struct net *net, if (!nf_reject_ip6hdr_validate(oldskb)) return NULL; + /* Don't reply to ICMPV6_DEST_UNREACH with ICMPV6_DEST_UNREACH */ + if (nf_skb_is_icmp6_unreach(oldskb)) + return NULL; + /* Include "As much of invoking packet as possible without the ICMPv6 * packet exceeding the minimum IPv6 MTU" in the ICMP payload. */ |