[NETFILTER]: Add SANE connection tracking helper
This is nf_conntrack_sane, a netfilter connection tracking helper module for the SANE protocol used by the 'saned' daemon to make scanners available via network. The SANE protocol uses separate control & data connections, similar to passive FTP. The helper module is needed to recognize the data connection as RELATED to the control one. Signed-off-by: Michal Schmidt <mschmidt@redhat.com> Signed-off-by: Patrick McHardy <kaber@trash.net> Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Michal Schmidt
David S. Miller
parent
719647e213
commit
6fecd19851
|
|
@ -0,0 +1,21 @@
|
|||
#ifndef _NF_CONNTRACK_SANE_H
|
||||
#define _NF_CONNTRACK_SANE_H
|
||||
/* SANE tracking. */
|
||||
|
||||
#ifdef __KERNEL__
|
||||
|
||||
#define SANE_PORT 6566
|
||||
|
||||
enum sane_state {
|
||||
SANE_STATE_NORMAL,
|
||||
SANE_STATE_START_REQUESTED,
|
||||
};
|
||||
|
||||
/* This structure exists only once per master */
|
||||
struct nf_ct_sane_master {
|
||||
enum sane_state state;
|
||||
};
|
||||
|
||||
#endif /* __KERNEL__ */
|
||||
|
||||
#endif /* _NF_CONNTRACK_SANE_H */
|
||||
|
|
@ -45,6 +45,7 @@ union nf_conntrack_expect_proto {
|
|||
#include <linux/netfilter/nf_conntrack_ftp.h>
|
||||
#include <linux/netfilter/nf_conntrack_pptp.h>
|
||||
#include <linux/netfilter/nf_conntrack_h323.h>
|
||||
#include <linux/netfilter/nf_conntrack_sane.h>
|
||||
|
||||
/* per conntrack: application helper private data */
|
||||
union nf_conntrack_help {
|
||||
|
|
@ -52,6 +53,7 @@ union nf_conntrack_help {
|
|||
struct nf_ct_ftp_master ct_ftp_info;
|
||||
struct nf_ct_pptp_master ct_pptp_info;
|
||||
struct nf_ct_h323_master ct_h323_info;
|
||||
struct nf_ct_sane_master ct_sane_info;
|
||||
};
|
||||
|
||||
#include <linux/types.h>
|
||||
|
|
|
|||
|
|
@ -235,6 +235,19 @@ config NF_CONNTRACK_PPTP
|
|||
|
||||
To compile it as a module, choose M here. If unsure, say N.
|
||||
|
||||
config NF_CONNTRACK_SANE
|
||||
tristate "SANE protocol support (EXPERIMENTAL)"
|
||||
depends on EXPERIMENTAL && NF_CONNTRACK
|
||||
help
|
||||
SANE is a protocol for remote access to scanners as implemented
|
||||
by the 'saned' daemon. Like FTP, it uses separate control and
|
||||
data connections.
|
||||
|
||||
With this module you can support SANE on a connection tracking
|
||||
firewall.
|
||||
|
||||
To compile it as a module, choose M here. If unsure, say N.
|
||||
|
||||
config NF_CONNTRACK_SIP
|
||||
tristate "SIP protocol support (EXPERIMENTAL)"
|
||||
depends on EXPERIMENTAL && NF_CONNTRACK
|
||||
|
|
|
|||
|
|
@ -29,6 +29,7 @@ obj-$(CONFIG_NF_CONNTRACK_H323) += nf_conntrack_h323.o
|
|||
obj-$(CONFIG_NF_CONNTRACK_IRC) += nf_conntrack_irc.o
|
||||
obj-$(CONFIG_NF_CONNTRACK_NETBIOS_NS) += nf_conntrack_netbios_ns.o
|
||||
obj-$(CONFIG_NF_CONNTRACK_PPTP) += nf_conntrack_pptp.o
|
||||
obj-$(CONFIG_NF_CONNTRACK_SANE) += nf_conntrack_sane.o
|
||||
obj-$(CONFIG_NF_CONNTRACK_SIP) += nf_conntrack_sip.o
|
||||
obj-$(CONFIG_NF_CONNTRACK_TFTP) += nf_conntrack_tftp.o
|
||||
|
||||
|
|
|
|||
|
|
@ -0,0 +1,242 @@
|
|||
/* SANE connection tracking helper
|
||||
* (SANE = Scanner Access Now Easy)
|
||||
* For documentation about the SANE network protocol see
|
||||
* http://www.sane-project.org/html/doc015.html
|
||||
*/
|
||||
|
||||
/* Copyright (C) 2007 Red Hat, Inc.
|
||||
* Author: Michal Schmidt <mschmidt@redhat.com>
|
||||
* Based on the FTP conntrack helper (net/netfilter/nf_conntrack_ftp.c):
|
||||
* (C) 1999-2001 Paul `Rusty' Russell
|
||||
* (C) 2002-2004 Netfilter Core Team <coreteam@netfilter.org>
|
||||
* (C) 2003,2004 USAGI/WIDE Project <http://www.linux-ipv6.org>
|
||||
* (C) 2003 Yasuyuki Kozakai @USAGI <yasuyuki.kozakai@toshiba.co.jp>
|
||||
*
|
||||
* 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/netfilter.h>
|
||||
#include <linux/in.h>
|
||||
#include <linux/tcp.h>
|
||||
#include <net/netfilter/nf_conntrack.h>
|
||||
#include <net/netfilter/nf_conntrack_helper.h>
|
||||
#include <net/netfilter/nf_conntrack_expect.h>
|
||||
#include <linux/netfilter/nf_conntrack_sane.h>
|
||||
|
||||
MODULE_LICENSE("GPL");
|
||||
MODULE_AUTHOR("Michal Schmidt <mschmidt@redhat.com>");
|
||||
MODULE_DESCRIPTION("SANE connection tracking helper");
|
||||
|
||||
static char *sane_buffer;
|
||||
|
||||
static DEFINE_SPINLOCK(nf_sane_lock);
|
||||
|
||||
#define MAX_PORTS 8
|
||||
static u_int16_t ports[MAX_PORTS];
|
||||
static unsigned int ports_c;
|
||||
module_param_array(ports, ushort, &ports_c, 0400);
|
||||
|
||||
#if 0
|
||||
#define DEBUGP printk
|
||||
#else
|
||||
#define DEBUGP(format, args...)
|
||||
#endif
|
||||
|
||||
struct sane_request {
|
||||
__be32 RPC_code;
|
||||
#define SANE_NET_START 7 /* RPC code */
|
||||
|
||||
__be32 handle;
|
||||
};
|
||||
|
||||
struct sane_reply_net_start {
|
||||
__be32 status;
|
||||
#define SANE_STATUS_SUCCESS 0
|
||||
|
||||
__be16 zero;
|
||||
__be16 port;
|
||||
/* other fields aren't interesting for conntrack */
|
||||
};
|
||||
|
||||
static int help(struct sk_buff **pskb,
|
||||
unsigned int protoff,
|
||||
struct nf_conn *ct,
|
||||
enum ip_conntrack_info ctinfo)
|
||||
{
|
||||
unsigned int dataoff, datalen;
|
||||
struct tcphdr _tcph, *th;
|
||||
char *sb_ptr;
|
||||
int ret = NF_ACCEPT;
|
||||
int dir = CTINFO2DIR(ctinfo);
|
||||
struct nf_ct_sane_master *ct_sane_info;
|
||||
struct nf_conntrack_expect *exp;
|
||||
struct nf_conntrack_tuple *tuple;
|
||||
struct sane_request *req;
|
||||
struct sane_reply_net_start *reply;
|
||||
int family = ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple.src.l3num;
|
||||
|
||||
ct_sane_info = &nfct_help(ct)->help.ct_sane_info;
|
||||
/* Until there's been traffic both ways, don't look in packets. */
|
||||
if (ctinfo != IP_CT_ESTABLISHED &&
|
||||
ctinfo != IP_CT_ESTABLISHED+IP_CT_IS_REPLY)
|
||||
return NF_ACCEPT;
|
||||
|
||||
/* Not a full tcp header? */
|
||||
th = skb_header_pointer(*pskb, protoff, sizeof(_tcph), &_tcph);
|
||||
if (th == NULL)
|
||||
return NF_ACCEPT;
|
||||
|
||||
/* No data? */
|
||||
dataoff = protoff + th->doff * 4;
|
||||
if (dataoff >= (*pskb)->len)
|
||||
return NF_ACCEPT;
|
||||
|
||||
datalen = (*pskb)->len - dataoff;
|
||||
|
||||
spin_lock_bh(&nf_sane_lock);
|
||||
sb_ptr = skb_header_pointer(*pskb, dataoff, datalen, sane_buffer);
|
||||
BUG_ON(sb_ptr == NULL);
|
||||
|
||||
if (dir == IP_CT_DIR_ORIGINAL) {
|
||||
if (datalen != sizeof(struct sane_request))
|
||||
goto out;
|
||||
|
||||
req = (struct sane_request *)sb_ptr;
|
||||
if (req->RPC_code != htonl(SANE_NET_START)) {
|
||||
/* Not an interesting command */
|
||||
ct_sane_info->state = SANE_STATE_NORMAL;
|
||||
goto out;
|
||||
}
|
||||
|
||||
/* We're interested in the next reply */
|
||||
ct_sane_info->state = SANE_STATE_START_REQUESTED;
|
||||
goto out;
|
||||
}
|
||||
|
||||
/* Is it a reply to an uninteresting command? */
|
||||
if (ct_sane_info->state != SANE_STATE_START_REQUESTED)
|
||||
goto out;
|
||||
|
||||
/* It's a reply to SANE_NET_START. */
|
||||
ct_sane_info->state = SANE_STATE_NORMAL;
|
||||
|
||||
if (datalen < sizeof(struct sane_reply_net_start)) {
|
||||
DEBUGP("nf_ct_sane: NET_START reply too short\n");
|
||||
goto out;
|
||||
}
|
||||
|
||||
reply = (struct sane_reply_net_start *)sb_ptr;
|
||||
if (reply->status != htonl(SANE_STATUS_SUCCESS)) {
|
||||
/* saned refused the command */
|
||||
DEBUGP("nf_ct_sane: unsuccessful SANE_STATUS = %u\n",
|
||||
ntohl(reply->status));
|
||||
goto out;
|
||||
}
|
||||
|
||||
/* Invalid saned reply? Ignore it. */
|
||||
if (reply->zero != 0)
|
||||
goto out;
|
||||
|
||||
exp = nf_conntrack_expect_alloc(ct);
|
||||
if (exp == NULL) {
|
||||
ret = NF_DROP;
|
||||
goto out;
|
||||
}
|
||||
|
||||
tuple = &ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple;
|
||||
nf_conntrack_expect_init(exp, family,
|
||||
&tuple->src.u3, &tuple->dst.u3,
|
||||
IPPROTO_TCP,
|
||||
NULL, &reply->port);
|
||||
|
||||
DEBUGP("nf_ct_sane: expect: ");
|
||||
NF_CT_DUMP_TUPLE(&exp->tuple);
|
||||
NF_CT_DUMP_TUPLE(&exp->mask);
|
||||
|
||||
/* Can't expect this? Best to drop packet now. */
|
||||
if (nf_conntrack_expect_related(exp) != 0)
|
||||
ret = NF_DROP;
|
||||
|
||||
nf_conntrack_expect_put(exp);
|
||||
|
||||
out:
|
||||
spin_unlock_bh(&nf_sane_lock);
|
||||
return ret;
|
||||
}
|
||||
|
||||
static struct nf_conntrack_helper sane[MAX_PORTS][2];
|
||||
static char sane_names[MAX_PORTS][2][sizeof("sane-65535")];
|
||||
|
||||
/* don't make this __exit, since it's called from __init ! */
|
||||
static void nf_conntrack_sane_fini(void)
|
||||
{
|
||||
int i, j;
|
||||
|
||||
for (i = 0; i < ports_c; i++) {
|
||||
for (j = 0; j < 2; j++) {
|
||||
DEBUGP("nf_ct_sane: unregistering helper for pf: %d "
|
||||
"port: %d\n",
|
||||
sane[i][j].tuple.src.l3num, ports[i]);
|
||||
nf_conntrack_helper_unregister(&sane[i][j]);
|
||||
}
|
||||
}
|
||||
|
||||
kfree(sane_buffer);
|
||||
}
|
||||
|
||||
static int __init nf_conntrack_sane_init(void)
|
||||
{
|
||||
int i, j = -1, ret = 0;
|
||||
char *tmpname;
|
||||
|
||||
sane_buffer = kmalloc(65536, GFP_KERNEL);
|
||||
if (!sane_buffer)
|
||||
return -ENOMEM;
|
||||
|
||||
if (ports_c == 0)
|
||||
ports[ports_c++] = SANE_PORT;
|
||||
|
||||
/* FIXME should be configurable whether IPv4 and IPv6 connections
|
||||
are tracked or not - YK */
|
||||
for (i = 0; i < ports_c; i++) {
|
||||
sane[i][0].tuple.src.l3num = PF_INET;
|
||||
sane[i][1].tuple.src.l3num = PF_INET6;
|
||||
for (j = 0; j < 2; j++) {
|
||||
sane[i][j].tuple.src.u.tcp.port = htons(ports[i]);
|
||||
sane[i][j].tuple.dst.protonum = IPPROTO_TCP;
|
||||
sane[i][j].mask.src.u.tcp.port = 0xFFFF;
|
||||
sane[i][j].mask.dst.protonum = 0xFF;
|
||||
sane[i][j].max_expected = 1;
|
||||
sane[i][j].timeout = 5 * 60; /* 5 Minutes */
|
||||
sane[i][j].me = THIS_MODULE;
|
||||
sane[i][j].help = help;
|
||||
tmpname = &sane_names[i][j][0];
|
||||
if (ports[i] == SANE_PORT)
|
||||
sprintf(tmpname, "sane");
|
||||
else
|
||||
sprintf(tmpname, "sane-%d", ports[i]);
|
||||
sane[i][j].name = tmpname;
|
||||
|
||||
DEBUGP("nf_ct_sane: registering helper for pf: %d "
|
||||
"port: %d\n",
|
||||
sane[i][j].tuple.src.l3num, ports[i]);
|
||||
ret = nf_conntrack_helper_register(&sane[i][j]);
|
||||
if (ret) {
|
||||
printk(KERN_ERR "nf_ct_sane: failed to "
|
||||
"register helper for pf: %d port: %d\n",
|
||||
sane[i][j].tuple.src.l3num, ports[i]);
|
||||
nf_conntrack_sane_fini();
|
||||
return ret;
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
return 0;
|
||||
}
|
||||
|
||||
module_init(nf_conntrack_sane_init);
|
||||
module_exit(nf_conntrack_sane_fini);
|
||||
Loading…
Reference in New Issue