IPVS: bug in ip_vs_ftp, same list heaad used in all netns.
[deliverable/linux.git] / net / netfilter / ipvs / ip_vs_ftp.c
CommitLineData
1da177e4
LT
1/*
2 * ip_vs_ftp.c: IPVS ftp application module
3 *
1da177e4
LT
4 * Authors: Wensong Zhang <wensong@linuxvirtualserver.org>
5 *
6 * Changes:
7 *
8 *
9 * This program is free software; you can redistribute it and/or
10 * modify it under the terms of the GNU General Public License
11 * as published by the Free Software Foundation; either version
12 * 2 of the License, or (at your option) any later version.
13 *
14 * Most code here is taken from ip_masq_ftp.c in kernel 2.2. The difference
15 * is that ip_vs_ftp module handles the reverse direction to ip_masq_ftp.
16 *
17 * IP_MASQ_FTP ftp masquerading module
18 *
19 * Version: @(#)ip_masq_ftp.c 0.04 02/05/96
20 *
21 * Author: Wouter Gadeyne
22 *
23 */
24
9aada7ac
HE
25#define KMSG_COMPONENT "IPVS"
26#define pr_fmt(fmt) KMSG_COMPONENT ": " fmt
27
1da177e4
LT
28#include <linux/module.h>
29#include <linux/moduleparam.h>
30#include <linux/kernel.h>
31#include <linux/skbuff.h>
32#include <linux/in.h>
33#include <linux/ip.h>
af1e1cf0 34#include <linux/netfilter.h>
7f1c4075
HE
35#include <net/netfilter/nf_conntrack.h>
36#include <net/netfilter/nf_conntrack_expect.h>
7bcbf81a 37#include <net/netfilter/nf_nat.h>
7f1c4075 38#include <net/netfilter/nf_nat_helper.h>
5a0e3ad6 39#include <linux/gfp.h>
1da177e4
LT
40#include <net/protocol.h>
41#include <net/tcp.h>
96d2ca4e 42#include <asm/unaligned.h>
1da177e4
LT
43
44#include <net/ip_vs.h>
45
46
47#define SERVER_STRING "227 Entering Passive Mode ("
48#define CLIENT_STRING "PORT "
49
50
51/*
52 * List of ports (up to IP_VS_APP_MAX_PORTS) to be handled by helper
53 * First port is set to the default port.
54 */
28b06c38
SH
55static unsigned short ports[IP_VS_APP_MAX_PORTS] = {21, 0};
56module_param_array(ports, ushort, NULL, 0);
70e76b76 57MODULE_PARM_DESC(ports, "Ports to monitor for FTP control commands");
1da177e4 58
1da177e4
LT
59
60/* Dummy variable */
61static int ip_vs_ftp_pasv;
62
63
64static int
65ip_vs_ftp_init_conn(struct ip_vs_app *app, struct ip_vs_conn *cp)
66{
f4bc17cd
JA
67 /* We use connection tracking for the command connection */
68 cp->flags |= IP_VS_CONN_F_NFCT;
1da177e4
LT
69 return 0;
70}
71
72
73static int
74ip_vs_ftp_done_conn(struct ip_vs_app *app, struct ip_vs_conn *cp)
75{
76 return 0;
77}
78
79
80/*
81 * Get <addr,port> from the string "xxx.xxx.xxx.xxx,ppp,ppp", started
82 * with the "pattern" and terminated with the "term" character.
83 * <addr,port> is in network order.
84 */
85static int ip_vs_ftp_get_addrport(char *data, char *data_limit,
86 const char *pattern, size_t plen, char term,
014d730d 87 __be32 *addr, __be16 *port,
1da177e4
LT
88 char **start, char **end)
89{
90 unsigned char p[6];
91 int i = 0;
92
93 if (data_limit - data < plen) {
94 /* check if there is partial match */
95 if (strnicmp(data, pattern, data_limit - data) == 0)
96 return -1;
97 else
98 return 0;
99 }
100
101 if (strnicmp(data, pattern, plen) != 0) {
102 return 0;
103 }
104 *start = data + plen;
105
106 for (data = *start; *data != term; data++) {
107 if (data == data_limit)
108 return -1;
109 }
110 *end = data;
111
112 memset(p, 0, sizeof(p));
113 for (data = *start; data != *end; data++) {
114 if (*data >= '0' && *data <= '9') {
115 p[i] = p[i]*10 + *data - '0';
116 } else if (*data == ',' && i < 5) {
117 i++;
118 } else {
119 /* unexpected character */
120 return -1;
121 }
122 }
123
124 if (i != 5)
125 return -1;
126
96d2ca4e
AV
127 *addr = get_unaligned((__be32 *)p);
128 *port = get_unaligned((__be16 *)(p + 4));
1da177e4
LT
129 return 1;
130}
131
1da177e4
LT
132/*
133 * Look at outgoing ftp packets to catch the response to a PASV command
134 * from the server (inside-to-outside).
135 * When we see one, we build a connection entry with the client address,
136 * client port 0 (unknown at the moment), the server address and the
137 * server port. Mark the current connection entry as a control channel
138 * of the new entry. All this work is just to make the data connection
139 * can be scheduled to the right server later.
140 *
141 * The outgoing packet should be something like
142 * "227 Entering Passive Mode (xxx,xxx,xxx,xxx,ppp,ppp)".
143 * xxx,xxx,xxx,xxx is the server address, ppp,ppp is the server port number.
144 */
145static int ip_vs_ftp_out(struct ip_vs_app *app, struct ip_vs_conn *cp,
3db05fea 146 struct sk_buff *skb, int *diff)
1da177e4
LT
147{
148 struct iphdr *iph;
149 struct tcphdr *th;
150 char *data, *data_limit;
151 char *start, *end;
28364a59 152 union nf_inet_addr from;
014d730d 153 __be16 port;
1da177e4
LT
154 struct ip_vs_conn *n_cp;
155 char buf[24]; /* xxx.xxx.xxx.xxx,ppp,ppp\000 */
156 unsigned buf_len;
7f1c4075
HE
157 int ret = 0;
158 enum ip_conntrack_info ctinfo;
159 struct nf_conn *ct;
4a85b96c 160 struct net *net;
1da177e4 161
a0eb662f
JV
162#ifdef CONFIG_IP_VS_IPV6
163 /* This application helper doesn't work with IPv6 yet,
164 * so turn this into a no-op for IPv6 packets
165 */
166 if (cp->af == AF_INET6)
167 return 1;
168#endif
169
1da177e4
LT
170 *diff = 0;
171
172 /* Only useful for established sessions */
173 if (cp->state != IP_VS_TCP_S_ESTABLISHED)
174 return 1;
175
176 /* Linear packets are much easier to deal with. */
3db05fea 177 if (!skb_make_writable(skb, skb->len))
1da177e4
LT
178 return 0;
179
180 if (cp->app_data == &ip_vs_ftp_pasv) {
3db05fea 181 iph = ip_hdr(skb);
1da177e4
LT
182 th = (struct tcphdr *)&(((char *)iph)[iph->ihl*4]);
183 data = (char *)th + (th->doff << 2);
3db05fea 184 data_limit = skb_tail_pointer(skb);
1da177e4
LT
185
186 if (ip_vs_ftp_get_addrport(data, data_limit,
187 SERVER_STRING,
188 sizeof(SERVER_STRING)-1, ')',
28364a59 189 &from.ip, &port,
1da177e4
LT
190 &start, &end) != 1)
191 return 1;
192
14d5e834
HH
193 IP_VS_DBG(7, "PASV response (%pI4:%d) -> %pI4:%d detected\n",
194 &from.ip, ntohs(port), &cp->caddr.ip, 0);
1da177e4
LT
195
196 /*
197 * Now update or create an connection entry for it
198 */
f11017ec
SH
199 {
200 struct ip_vs_conn_param p;
6e67e586
HS
201 ip_vs_conn_fill_param(ip_vs_conn_net(cp), AF_INET,
202 iph->protocol, &from, port,
203 &cp->caddr, 0, &p);
f11017ec
SH
204 n_cp = ip_vs_conn_out_get(&p);
205 }
1da177e4 206 if (!n_cp) {
f11017ec 207 struct ip_vs_conn_param p;
6e67e586
HS
208 ip_vs_conn_fill_param(ip_vs_conn_net(cp),
209 AF_INET, IPPROTO_TCP, &cp->caddr,
f11017ec
SH
210 0, &cp->vaddr, port, &p);
211 n_cp = ip_vs_conn_new(&p, &from, port,
f4bc17cd
JA
212 IP_VS_CONN_F_NO_CPORT |
213 IP_VS_CONN_F_NFCT,
0e051e68 214 cp->dest, skb->mark);
1da177e4
LT
215 if (!n_cp)
216 return 0;
217
218 /* add its controller */
219 ip_vs_control_add(n_cp, cp);
220 }
221
222 /*
223 * Replace the old passive address with the new one
224 */
28364a59 225 from.ip = n_cp->vaddr.ip;
1da177e4 226 port = n_cp->vport;
1da05f50
JP
227 snprintf(buf, sizeof(buf), "%u,%u,%u,%u,%u,%u",
228 ((unsigned char *)&from.ip)[0],
229 ((unsigned char *)&from.ip)[1],
230 ((unsigned char *)&from.ip)[2],
231 ((unsigned char *)&from.ip)[3],
232 ntohs(port) >> 8,
233 ntohs(port) & 0xFF);
234
1da177e4
LT
235 buf_len = strlen(buf);
236
7f1c4075 237 ct = nf_ct_get(skb, &ctinfo);
7bcbf81a 238 if (ct && !nf_ct_is_untracked(ct) && nfct_nat(ct)) {
7f1c4075
HE
239 /* If mangling fails this function will return 0
240 * which will cause the packet to be dropped.
241 * Mangling can only fail under memory pressure,
242 * hopefully it will succeed on the retransmitted
243 * packet.
244 */
245 ret = nf_nat_mangle_tcp_packet(skb, ct, ctinfo,
246 start-data, end-start,
247 buf, buf_len);
8b27b10f 248 if (ret) {
f4bc17cd
JA
249 ip_vs_nfct_expect_related(skb, ct, n_cp,
250 IPPROTO_TCP, 0, 0);
8b27b10f
JA
251 if (skb->ip_summed == CHECKSUM_COMPLETE)
252 skb->ip_summed = CHECKSUM_UNNECESSARY;
253 /* csum is updated */
254 ret = 1;
255 }
7f1c4075
HE
256 }
257
1da177e4 258 /*
7f1c4075
HE
259 * Not setting 'diff' is intentional, otherwise the sequence
260 * would be adjusted twice.
1da177e4 261 */
1da177e4 262
4a85b96c 263 net = skb_net(skb);
1da177e4 264 cp->app_data = NULL;
4a85b96c 265 ip_vs_tcp_conn_listen(net, n_cp);
1da177e4
LT
266 ip_vs_conn_put(n_cp);
267 return ret;
268 }
269 return 1;
270}
271
272
273/*
274 * Look at incoming ftp packets to catch the PASV/PORT command
275 * (outside-to-inside).
276 *
277 * The incoming packet having the PORT command should be something like
278 * "PORT xxx,xxx,xxx,xxx,ppp,ppp\n".
279 * xxx,xxx,xxx,xxx is the client address, ppp,ppp is the client port number.
280 * In this case, we create a connection entry using the client address and
281 * port, so that the active ftp data connection from the server can reach
282 * the client.
283 */
284static int ip_vs_ftp_in(struct ip_vs_app *app, struct ip_vs_conn *cp,
3db05fea 285 struct sk_buff *skb, int *diff)
1da177e4
LT
286{
287 struct iphdr *iph;
288 struct tcphdr *th;
289 char *data, *data_start, *data_limit;
290 char *start, *end;
28364a59 291 union nf_inet_addr to;
014d730d 292 __be16 port;
1da177e4 293 struct ip_vs_conn *n_cp;
4a85b96c 294 struct net *net;
1da177e4 295
a0eb662f
JV
296#ifdef CONFIG_IP_VS_IPV6
297 /* This application helper doesn't work with IPv6 yet,
298 * so turn this into a no-op for IPv6 packets
299 */
300 if (cp->af == AF_INET6)
301 return 1;
302#endif
303
1da177e4
LT
304 /* no diff required for incoming packets */
305 *diff = 0;
306
307 /* Only useful for established sessions */
308 if (cp->state != IP_VS_TCP_S_ESTABLISHED)
309 return 1;
310
311 /* Linear packets are much easier to deal with. */
3db05fea 312 if (!skb_make_writable(skb, skb->len))
1da177e4
LT
313 return 0;
314
315 /*
316 * Detecting whether it is passive
317 */
3db05fea 318 iph = ip_hdr(skb);
1da177e4
LT
319 th = (struct tcphdr *)&(((char *)iph)[iph->ihl*4]);
320
321 /* Since there may be OPTIONS in the TCP packet and the HLEN is
322 the length of the header in 32-bit multiples, it is accurate
323 to calculate data address by th+HLEN*4 */
324 data = data_start = (char *)th + (th->doff << 2);
3db05fea 325 data_limit = skb_tail_pointer(skb);
1da177e4
LT
326
327 while (data <= data_limit - 6) {
328 if (strnicmp(data, "PASV\r\n", 6) == 0) {
329 /* Passive mode on */
5e7ddac7 330 IP_VS_DBG(7, "got PASV at %td of %td\n",
1da177e4
LT
331 data - data_start,
332 data_limit - data_start);
333 cp->app_data = &ip_vs_ftp_pasv;
334 return 1;
335 }
336 data++;
337 }
338
339 /*
340 * To support virtual FTP server, the scenerio is as follows:
341 * FTP client ----> Load Balancer ----> FTP server
342 * First detect the port number in the application data,
343 * then create a new connection entry for the coming data
344 * connection.
345 */
346 if (ip_vs_ftp_get_addrport(data_start, data_limit,
347 CLIENT_STRING, sizeof(CLIENT_STRING)-1,
28364a59 348 '\r', &to.ip, &port,
1da177e4
LT
349 &start, &end) != 1)
350 return 1;
351
14d5e834 352 IP_VS_DBG(7, "PORT %pI4:%d detected\n", &to.ip, ntohs(port));
1da177e4
LT
353
354 /* Passive mode off */
355 cp->app_data = NULL;
356
357 /*
358 * Now update or create a connection entry for it
359 */
14d5e834 360 IP_VS_DBG(7, "protocol %s %pI4:%d %pI4:%d\n",
1da177e4 361 ip_vs_proto_name(iph->protocol),
14d5e834 362 &to.ip, ntohs(port), &cp->vaddr.ip, 0);
1da177e4 363
f11017ec
SH
364 {
365 struct ip_vs_conn_param p;
6e67e586
HS
366 ip_vs_conn_fill_param(ip_vs_conn_net(cp), AF_INET,
367 iph->protocol, &to, port, &cp->vaddr,
368 htons(ntohs(cp->vport)-1), &p);
f11017ec
SH
369 n_cp = ip_vs_conn_in_get(&p);
370 if (!n_cp) {
371 n_cp = ip_vs_conn_new(&p, &cp->daddr,
372 htons(ntohs(cp->dport)-1),
0e051e68
HS
373 IP_VS_CONN_F_NFCT, cp->dest,
374 skb->mark);
f11017ec
SH
375 if (!n_cp)
376 return 0;
1da177e4 377
f11017ec
SH
378 /* add its controller */
379 ip_vs_control_add(n_cp, cp);
380 }
1da177e4
LT
381 }
382
383 /*
384 * Move tunnel to listen state
385 */
4a85b96c
HS
386 net = skb_net(skb);
387 ip_vs_tcp_conn_listen(net, n_cp);
1da177e4
LT
388 ip_vs_conn_put(n_cp);
389
390 return 1;
391}
392
393
394static struct ip_vs_app ip_vs_ftp = {
395 .name = "ftp",
396 .type = IP_VS_APP_TYPE_FTP,
397 .protocol = IPPROTO_TCP,
398 .module = THIS_MODULE,
399 .incs_list = LIST_HEAD_INIT(ip_vs_ftp.incs_list),
400 .init_conn = ip_vs_ftp_init_conn,
401 .done_conn = ip_vs_ftp_done_conn,
402 .bind_conn = NULL,
403 .unbind_conn = NULL,
404 .pkt_out = ip_vs_ftp_out,
405 .pkt_in = ip_vs_ftp_in,
406};
407
1da177e4 408/*
61b1ab45 409 * per netns ip_vs_ftp initialization
1da177e4 410 */
61b1ab45 411static int __net_init __ip_vs_ftp_init(struct net *net)
1da177e4
LT
412{
413 int i, ret;
c74c0bfe
HS
414 struct ip_vs_app *app;
415 struct netns_ipvs *ipvs = net_ipvs(net);
416
417 app = kmemdup(&ip_vs_ftp, sizeof(struct ip_vs_app), GFP_KERNEL);
418 if (!app)
419 return -ENOMEM;
420 INIT_LIST_HEAD(&app->a_list);
421 INIT_LIST_HEAD(&app->incs_list);
422 ipvs->ftp_app = app;
1da177e4 423
ab8a5e84 424 ret = register_ip_vs_app(net, app);
1da177e4 425 if (ret)
c74c0bfe 426 goto err_exit;
1da177e4
LT
427
428 for (i=0; i<IP_VS_APP_MAX_PORTS; i++) {
429 if (!ports[i])
430 continue;
ab8a5e84 431 ret = register_ip_vs_app_inc(net, app, app->protocol, ports[i]);
1da177e4 432 if (ret)
c74c0bfe 433 goto err_unreg;
1e3e238e
HE
434 pr_info("%s: loaded support on port[%d] = %d\n",
435 app->name, i, ports[i]);
1da177e4 436 }
c74c0bfe 437 return 0;
1da177e4 438
c74c0bfe
HS
439err_unreg:
440 unregister_ip_vs_app(net, app);
441err_exit:
442 kfree(ipvs->ftp_app);
1da177e4
LT
443 return ret;
444}
61b1ab45
HS
445/*
446 * netns exit
447 */
448static void __ip_vs_ftp_exit(struct net *net)
449{
c74c0bfe 450 struct netns_ipvs *ipvs = net_ipvs(net);
61b1ab45 451
c74c0bfe
HS
452 unregister_ip_vs_app(net, ipvs->ftp_app);
453 kfree(ipvs->ftp_app);
61b1ab45
HS
454}
455
456static struct pernet_operations ip_vs_ftp_ops = {
457 .init = __ip_vs_ftp_init,
458 .exit = __ip_vs_ftp_exit,
459};
1da177e4 460
61b1ab45
HS
461int __init ip_vs_ftp_init(void)
462{
463 int rv;
464
465 rv = register_pernet_subsys(&ip_vs_ftp_ops);
466 return rv;
467}
1da177e4
LT
468
469/*
470 * ip_vs_ftp finish.
471 */
472static void __exit ip_vs_ftp_exit(void)
473{
61b1ab45 474 unregister_pernet_subsys(&ip_vs_ftp_ops);
1da177e4
LT
475}
476
477
478module_init(ip_vs_ftp_init);
479module_exit(ip_vs_ftp_exit);
480MODULE_LICENSE("GPL");
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