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netfilter: nf_nat: support IPv6 in FTP NAT helper

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Signed-off-by: Patrick McHardy <kaber@trash.net>
This commit is contained in:
Patrick McHardy 2012-08-26 19:14:20 +02:00 • committed by Pablo Neira Ayuso
parent ed72d9e294
commit d33cbeeb1a
6 changed files with 27 additions and 20 deletions
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5
net/netfilter/Kconfig
View file

@ -380,6 +380,11 @@ config NF_NAT_PROTO_SCTP
depends on NF_NAT && NF_CT_PROTO_SCTP
select LIBCRC32C
config NF_NAT_FTP
tristate
depends on NF_CONNTRACK && NF_NAT
default NF_NAT && NF_CONNTRACK_FTP
endif # NF_CONNTRACK
# transparent proxy support

3
net/netfilter/Makefile
View file

@ -54,6 +54,9 @@ obj-$(CONFIG_NF_NAT_PROTO_DCCP) += nf_nat_proto_dccp.o
obj-$(CONFIG_NF_NAT_PROTO_UDPLITE) += nf_nat_proto_udplite.o
obj-$(CONFIG_NF_NAT_PROTO_SCTP) += nf_nat_proto_sctp.o
# NAT helpers
obj-$(CONFIG_NF_NAT_FTP) += nf_nat_ftp.o
# transparent proxy support
obj-$(CONFIG_NETFILTER_TPROXY) += nf_tproxy_core.o

3
net/netfilter/nf_conntrack_ftp.c
View file

@ -488,8 +488,7 @@ static int help(struct sk_buff *skb,
/* Now, NAT might want to mangle the packet, and register the
* (possibly changed) expectation itself. */
nf_nat_ftp = rcu_dereference(nf_nat_ftp_hook);
if (nf_nat_ftp && nf_ct_l3num(ct) == NFPROTO_IPV4 &&
ct->status & IPS_NAT_MASK)
if (nf_nat_ftp && ct->status & IPS_NAT_MASK)
ret = nf_nat_ftp(skb, ctinfo, search[dir][i].ftptype,
protoff, matchoff, matchlen, exp);
else {

143
net/netfilter/nf_nat_ftp.c Normal file
View file

@ -0,0 +1,143 @@
/* FTP extension for TCP NAT alteration. */
/* (C) 1999-2001 Paul `Rusty' Russell
* (C) 2002-2006 Netfilter Core Team <coreteam@netfilter.org>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*/
#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/inet.h>
#include <linux/tcp.h>
#include <linux/netfilter_ipv4.h>
#include <net/netfilter/nf_nat.h>
#include <net/netfilter/nf_nat_helper.h>
#include <net/netfilter/nf_conntrack_helper.h>
#include <net/netfilter/nf_conntrack_expect.h>
#include <linux/netfilter/nf_conntrack_ftp.h>
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Rusty Russell <rusty@rustcorp.com.au>");
MODULE_DESCRIPTION("ftp NAT helper");
MODULE_ALIAS("ip_nat_ftp");
/* FIXME: Time out? --RR */
static int nf_nat_ftp_fmt_cmd(struct nf_conn *ct, enum nf_ct_ftp_type type,
char *buffer, size_t buflen,
union nf_inet_addr *addr, u16 port)
{
switch (type) {
case NF_CT_FTP_PORT:
case NF_CT_FTP_PASV:
return snprintf(buffer, buflen, "%u,%u,%u,%u,%u,%u",
((unsigned char *)&addr->ip)[0],
((unsigned char *)&addr->ip)[1],
((unsigned char *)&addr->ip)[2],
((unsigned char *)&addr->ip)[3],
port >> 8,
port & 0xFF);
case NF_CT_FTP_EPRT:
if (nf_ct_l3num(ct) == NFPROTO_IPV4)
return snprintf(buffer, buflen, "|1|%pI4|%u|",
&addr->ip, port);
else
return snprintf(buffer, buflen, "|2|%pI6|%u|",
&addr->ip6, port);
case NF_CT_FTP_EPSV:
return snprintf(buffer, buflen, "|||%u|", port);
}
return 0;
}
/* So, this packet has hit the connection tracking matching code.
Mangle it, and change the expectation to match the new version. */
static unsigned int nf_nat_ftp(struct sk_buff *skb,
enum ip_conntrack_info ctinfo,
enum nf_ct_ftp_type type,
unsigned int protoff,
unsigned int matchoff,
unsigned int matchlen,
struct nf_conntrack_expect *exp)
{
union nf_inet_addr newaddr;
u_int16_t port;
int dir = CTINFO2DIR(ctinfo);
struct nf_conn *ct = exp->master;
char buffer[sizeof("|1||65535|") + INET6_ADDRSTRLEN];
unsigned int buflen;
pr_debug("FTP_NAT: type %i, off %u len %u\n", type, matchoff, matchlen);
/* Connection will come from wherever this packet goes, hence !dir */
newaddr = ct->tuplehash[!dir].tuple.dst.u3;
exp->saved_proto.tcp.port = exp->tuple.dst.u.tcp.port;
exp->dir = !dir;
/* When you see the packet, we need to NAT it the same as the
* this one. */
exp->expectfn = nf_nat_follow_master;
/* Try to get same port: if not, try to change it. */
for (port = ntohs(exp->saved_proto.tcp.port); port != 0; port++) {
int ret;
exp->tuple.dst.u.tcp.port = htons(port);
ret = nf_ct_expect_related(exp);
if (ret == 0)
break;
else if (ret != -EBUSY) {
port = 0;
break;
}
}
if (port == 0)
return NF_DROP;
buflen = nf_nat_ftp_fmt_cmd(ct, type, buffer, sizeof(buffer),
&newaddr, port);
if (!buflen)
goto out;
pr_debug("calling nf_nat_mangle_tcp_packet\n");
if (!nf_nat_mangle_tcp_packet(skb, ct, ctinfo, protoff, matchoff,
matchlen, buffer, buflen))
goto out;
return NF_ACCEPT;
out:
nf_ct_unexpect_related(exp);
return NF_DROP;
}
static void __exit nf_nat_ftp_fini(void)
{
RCU_INIT_POINTER(nf_nat_ftp_hook, NULL);
synchronize_rcu();
}
static int __init nf_nat_ftp_init(void)
{
BUG_ON(nf_nat_ftp_hook != NULL);
RCU_INIT_POINTER(nf_nat_ftp_hook, nf_nat_ftp);
return 0;
}
/* Prior to 2.6.11, we had a ports param. No longer, but don't break users. */
static int warn_set(const char *val, struct kernel_param *kp)
{
printk(KERN_INFO KBUILD_MODNAME
": kernel >= 2.6.10 only uses 'ports' for conntrack modules\n");
return 0;
}
module_param_call(ports, warn_set, NULL, NULL, 0);
module_init(nf_nat_ftp_init);
module_exit(nf_nat_ftp_fini);