diff --git a/net/ipv6/netfilter/ip6t_NPT.c b/net/ipv6/netfilter/ip6t_NPT.c index 9ee077bf4f49..787c74aa85e3 100644 --- a/net/ipv6/netfilter/ip6t_NPT.c +++ b/net/ipv6/netfilter/ip6t_NPT.c @@ -77,16 +77,43 @@ static bool ip6t_npt_map_pfx(const struct ip6t_npt_tginfo *npt, return true; } +static struct ipv6hdr *icmpv6_bounced_ipv6hdr(struct sk_buff *skb, + struct ipv6hdr *_bounced_hdr) +{ + if (ipv6_hdr(skb)->nexthdr != IPPROTO_ICMPV6) + return NULL; + + if (!icmpv6_is_err(icmp6_hdr(skb)->icmp6_type)) + return NULL; + + return skb_header_pointer(skb, + skb_transport_offset(skb) + sizeof(struct icmp6hdr), + sizeof(struct ipv6hdr), + _bounced_hdr); +} + static unsigned int ip6t_snpt_tg(struct sk_buff *skb, const struct xt_action_param *par) { const struct ip6t_npt_tginfo *npt = par->targinfo; + struct ipv6hdr _bounced_hdr; + struct ipv6hdr *bounced_hdr; + struct in6_addr bounced_pfx; if (!ip6t_npt_map_pfx(npt, &ipv6_hdr(skb)->saddr)) { icmpv6_send(skb, ICMPV6_PARAMPROB, ICMPV6_HDR_FIELD, offsetof(struct ipv6hdr, saddr)); return NF_DROP; } + + /* rewrite dst addr of bounced packet which was sent to dst range */ + bounced_hdr = icmpv6_bounced_ipv6hdr(skb, &_bounced_hdr); + if (bounced_hdr) { + ipv6_addr_prefix(&bounced_pfx, &bounced_hdr->daddr, npt->src_pfx_len); + if (ipv6_addr_cmp(&bounced_pfx, &npt->src_pfx.in6) == 0) + ip6t_npt_map_pfx(npt, &bounced_hdr->daddr); + } + return XT_CONTINUE; } @@ -94,12 +121,24 @@ static unsigned int ip6t_dnpt_tg(struct sk_buff *skb, const struct xt_action_param *par) { const struct ip6t_npt_tginfo *npt = par->targinfo; + struct ipv6hdr _bounced_hdr; + struct ipv6hdr *bounced_hdr; + struct in6_addr bounced_pfx; if (!ip6t_npt_map_pfx(npt, &ipv6_hdr(skb)->daddr)) { icmpv6_send(skb, ICMPV6_PARAMPROB, ICMPV6_HDR_FIELD, offsetof(struct ipv6hdr, daddr)); return NF_DROP; } + + /* rewrite src addr of bounced packet which was sent from dst range */ + bounced_hdr = icmpv6_bounced_ipv6hdr(skb, &_bounced_hdr); + if (bounced_hdr) { + ipv6_addr_prefix(&bounced_pfx, &bounced_hdr->saddr, npt->src_pfx_len); + if (ipv6_addr_cmp(&bounced_pfx, &npt->src_pfx.in6) == 0) + ip6t_npt_map_pfx(npt, &bounced_hdr->saddr); + } + return XT_CONTINUE; }