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-rw-r--r--net/ipv4/netfilter/ip_nat_core.c18
1 files changed, 9 insertions, 9 deletions
diff --git a/net/ipv4/netfilter/ip_nat_core.c b/net/ipv4/netfilter/ip_nat_core.c
index c1a61462507f..1741d555ad0d 100644
--- a/net/ipv4/netfilter/ip_nat_core.c
+++ b/net/ipv4/netfilter/ip_nat_core.c
@@ -434,6 +434,7 @@ int ip_nat_icmp_reply_translation(struct sk_buff **pskb,
434 } *inside; 434 } *inside;
435 struct ip_conntrack_tuple inner, target; 435 struct ip_conntrack_tuple inner, target;
436 int hdrlen = (*pskb)->nh.iph->ihl * 4; 436 int hdrlen = (*pskb)->nh.iph->ihl * 4;
437 unsigned long statusbit;
437 438
438 if (!skb_make_writable(pskb, hdrlen + sizeof(*inside))) 439 if (!skb_make_writable(pskb, hdrlen + sizeof(*inside)))
439 return 0; 440 return 0;
@@ -495,17 +496,16 @@ int ip_nat_icmp_reply_translation(struct sk_buff **pskb,
495 496
496 /* Change outer to look the reply to an incoming packet 497 /* Change outer to look the reply to an incoming packet
497 * (proto 0 means don't invert per-proto part). */ 498 * (proto 0 means don't invert per-proto part). */
499 if (manip == IP_NAT_MANIP_SRC)
500 statusbit = IPS_SRC_NAT;
501 else
502 statusbit = IPS_DST_NAT;
498 503
499 /* Obviously, we need to NAT destination IP, but source IP 504 /* Invert if this is reply dir. */
500 should be NAT'ed only if it is from a NAT'd host. 505 if (dir == IP_CT_DIR_REPLY)
506 statusbit ^= IPS_NAT_MASK;
501 507
502 Explanation: some people use NAT for anonymizing. Also, 508 if (ct->status & statusbit) {
503 CERT recommends dropping all packets from private IP
504 addresses (although ICMP errors from internal links with
505 such addresses are not too uncommon, as Alan Cox points
506 out) */
507 if (manip != IP_NAT_MANIP_SRC
508 || ((*pskb)->nh.iph->saddr == ct->tuplehash[dir].tuple.src.ip)) {
509 invert_tuplepr(&target, &ct->tuplehash[!dir].tuple); 509 invert_tuplepr(&target, &ct->tuplehash[!dir].tuple);
510 if (!manip_pkt(0, pskb, 0, &target, manip)) 510 if (!manip_pkt(0, pskb, 0, &target, manip))
511 return 0; 511 return 0;