2006-12-03 06:07:44 +00:00
|
|
|
/* 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>
|
2012-08-26 17:14:20 +00:00
|
|
|
#include <linux/inet.h>
|
2006-12-03 06:07:44 +00:00
|
|
|
#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 */
|
|
|
|
|
2012-08-26 17:14:20 +00:00
|
|
|
static int nf_nat_ftp_fmt_cmd(struct nf_conn *ct, enum nf_ct_ftp_type type,
|
2010-01-11 10:49:51 +00:00
|
|
|
char *buffer, size_t buflen,
|
2012-08-26 17:14:20 +00:00
|
|
|
union nf_inet_addr *addr, u16 port)
|
2006-12-03 06:07:44 +00:00
|
|
|
{
|
2010-01-11 10:49:51 +00:00
|
|
|
switch (type) {
|
|
|
|
case NF_CT_FTP_PORT:
|
|
|
|
case NF_CT_FTP_PASV:
|
|
|
|
return snprintf(buffer, buflen, "%u,%u,%u,%u,%u,%u",
|
2012-08-26 17:14:20 +00:00
|
|
|
((unsigned char *)&addr->ip)[0],
|
|
|
|
((unsigned char *)&addr->ip)[1],
|
|
|
|
((unsigned char *)&addr->ip)[2],
|
|
|
|
((unsigned char *)&addr->ip)[3],
|
2010-01-11 10:49:51 +00:00
|
|
|
port >> 8,
|
|
|
|
port & 0xFF);
|
|
|
|
case NF_CT_FTP_EPRT:
|
2012-08-26 17:14:20 +00:00
|
|
|
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);
|
2010-01-11 10:49:51 +00:00
|
|
|
case NF_CT_FTP_EPSV:
|
|
|
|
return snprintf(buffer, buflen, "|||%u|", port);
|
|
|
|
}
|
2006-12-03 06:07:44 +00:00
|
|
|
|
2010-01-11 10:49:51 +00:00
|
|
|
return 0;
|
2006-12-03 06:07:44 +00:00
|
|
|
}
|
|
|
|
|
|
|
|
/* So, this packet has hit the connection tracking matching code.
|
|
|
|
Mangle it, and change the expectation to match the new version. */
|
2007-10-15 07:53:15 +00:00
|
|
|
static unsigned int nf_nat_ftp(struct sk_buff *skb,
|
2006-12-03 06:07:44 +00:00
|
|
|
enum ip_conntrack_info ctinfo,
|
|
|
|
enum nf_ct_ftp_type type,
|
2012-08-26 17:14:04 +00:00
|
|
|
unsigned int protoff,
|
2006-12-03 06:07:44 +00:00
|
|
|
unsigned int matchoff,
|
|
|
|
unsigned int matchlen,
|
2007-05-24 23:41:50 +00:00
|
|
|
struct nf_conntrack_expect *exp)
|
2006-12-03 06:07:44 +00:00
|
|
|
{
|
2012-08-26 17:14:20 +00:00
|
|
|
union nf_inet_addr newaddr;
|
2006-12-03 06:07:44 +00:00
|
|
|
u_int16_t port;
|
|
|
|
int dir = CTINFO2DIR(ctinfo);
|
|
|
|
struct nf_conn *ct = exp->master;
|
2012-08-26 17:14:20 +00:00
|
|
|
char buffer[sizeof("|1||65535|") + INET6_ADDRSTRLEN];
|
2010-01-11 10:49:51 +00:00
|
|
|
unsigned int buflen;
|
2006-12-03 06:07:44 +00:00
|
|
|
|
2007-07-08 05:39:38 +00:00
|
|
|
pr_debug("FTP_NAT: type %i, off %u len %u\n", type, matchoff, matchlen);
|
2006-12-03 06:07:44 +00:00
|
|
|
|
|
|
|
/* Connection will come from wherever this packet goes, hence !dir */
|
2012-08-26 17:14:20 +00:00
|
|
|
newaddr = ct->tuplehash[!dir].tuple.dst.u3;
|
2006-12-03 06:07:44 +00:00
|
|
|
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++) {
|
2010-09-22 06:34:12 +00:00
|
|
|
int ret;
|
|
|
|
|
2006-12-03 06:07:44 +00:00
|
|
|
exp->tuple.dst.u.tcp.port = htons(port);
|
2010-09-22 06:34:12 +00:00
|
|
|
ret = nf_ct_expect_related(exp);
|
|
|
|
if (ret == 0)
|
|
|
|
break;
|
|
|
|
else if (ret != -EBUSY) {
|
|
|
|
port = 0;
|
2006-12-03 06:07:44 +00:00
|
|
|
break;
|
2010-09-22 06:34:12 +00:00
|
|
|
}
|
2006-12-03 06:07:44 +00:00
|
|
|
}
|
|
|
|
|
|
|
|
if (port == 0)
|
|
|
|
return NF_DROP;
|
|
|
|
|
2012-08-26 17:14:20 +00:00
|
|
|
buflen = nf_nat_ftp_fmt_cmd(ct, type, buffer, sizeof(buffer),
|
|
|
|
&newaddr, port);
|
2010-01-11 10:49:51 +00:00
|
|
|
if (!buflen)
|
|
|
|
goto out;
|
|
|
|
|
|
|
|
pr_debug("calling nf_nat_mangle_tcp_packet\n");
|
|
|
|
|
2012-08-26 17:14:04 +00:00
|
|
|
if (!nf_nat_mangle_tcp_packet(skb, ct, ctinfo, protoff, matchoff,
|
2010-01-11 10:49:51 +00:00
|
|
|
matchlen, buffer, buflen))
|
|
|
|
goto out;
|
|
|
|
|
2006-12-03 06:07:44 +00:00
|
|
|
return NF_ACCEPT;
|
2010-01-11 10:49:51 +00:00
|
|
|
|
|
|
|
out:
|
|
|
|
nf_ct_unexpect_related(exp);
|
|
|
|
return NF_DROP;
|
2006-12-03 06:07:44 +00:00
|
|
|
}
|
|
|
|
|
|
|
|
static void __exit nf_nat_ftp_fini(void)
|
|
|
|
{
|
2011-08-01 16:19:00 +00:00
|
|
|
RCU_INIT_POINTER(nf_nat_ftp_hook, NULL);
|
2006-12-03 06:07:44 +00:00
|
|
|
synchronize_rcu();
|
|
|
|
}
|
|
|
|
|
|
|
|
static int __init nf_nat_ftp_init(void)
|
|
|
|
{
|
2007-11-06 04:43:30 +00:00
|
|
|
BUG_ON(nf_nat_ftp_hook != NULL);
|
2011-08-01 16:19:00 +00:00
|
|
|
RCU_INIT_POINTER(nf_nat_ftp_hook, nf_nat_ftp);
|
2006-12-03 06:07:44 +00:00
|
|
|
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);
|