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25#define KMSG_COMPONENT "IPVS"
26#define pr_fmt(fmt) KMSG_COMPONENT ": " fmt
27
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>
34#include <linux/netfilter.h>
35#include <net/netfilter/nf_conntrack.h>
36#include <net/netfilter/nf_conntrack_expect.h>
37#include <net/netfilter/nf_nat.h>
38#include <net/netfilter/nf_nat_helper.h>
39#include <linux/gfp.h>
40#include <net/protocol.h>
41#include <net/tcp.h>
42#include <asm/unaligned.h>
43
44#include <net/ip_vs.h>
45
46
47#define SERVER_STRING "227 "
48#define CLIENT_STRING "PORT"
49
50
51
52
53
54
55static unsigned int ports_count = 1;
56static unsigned short ports[IP_VS_APP_MAX_PORTS] = {21, 0};
57module_param_array(ports, ushort, &ports_count, 0444);
58MODULE_PARM_DESC(ports, "Ports to monitor for FTP control commands");
59
60
61
62static int ip_vs_ftp_pasv;
63
64
65static int
66ip_vs_ftp_init_conn(struct ip_vs_app *app, struct ip_vs_conn *cp)
67{
68
69 cp->flags |= IP_VS_CONN_F_NFCT;
70 return 0;
71}
72
73
74static int
75ip_vs_ftp_done_conn(struct ip_vs_app *app, struct ip_vs_conn *cp)
76{
77 return 0;
78}
79
80
81
82
83
84
85
86
87static int ip_vs_ftp_get_addrport(char *data, char *data_limit,
88 const char *pattern, size_t plen,
89 char skip, char term,
90 __be32 *addr, __be16 *port,
91 char **start, char **end)
92{
93 char *s, c;
94 unsigned char p[6];
95 int i = 0;
96
97 if (data_limit - data < plen) {
98
99 if (strnicmp(data, pattern, data_limit - data) == 0)
100 return -1;
101 else
102 return 0;
103 }
104
105 if (strnicmp(data, pattern, plen) != 0) {
106 return 0;
107 }
108 s = data + plen;
109 if (skip) {
110 int found = 0;
111
112 for (;; s++) {
113 if (s == data_limit)
114 return -1;
115 if (!found) {
116 if (*s == skip)
117 found = 1;
118 } else if (*s != skip) {
119 break;
120 }
121 }
122 }
123
124 for (data = s; ; data++) {
125 if (data == data_limit)
126 return -1;
127 if (*data == term)
128 break;
129 }
130 *end = data;
131
132 memset(p, 0, sizeof(p));
133 for (data = s; ; data++) {
134 c = *data;
135 if (c == term)
136 break;
137 if (c >= '0' && c <= '9') {
138 p[i] = p[i]*10 + c - '0';
139 } else if (c == ',' && i < 5) {
140 i++;
141 } else {
142
143 return -1;
144 }
145 }
146
147 if (i != 5)
148 return -1;
149
150 *start = s;
151 *addr = get_unaligned((__be32 *) p);
152 *port = get_unaligned((__be16 *) (p + 4));
153 return 1;
154}
155
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167
168
169static int ip_vs_ftp_out(struct ip_vs_app *app, struct ip_vs_conn *cp,
170 struct sk_buff *skb, int *diff)
171{
172 struct iphdr *iph;
173 struct tcphdr *th;
174 char *data, *data_limit;
175 char *start, *end;
176 union nf_inet_addr from;
177 __be16 port;
178 struct ip_vs_conn *n_cp;
179 char buf[24];
180 unsigned int buf_len;
181 int ret = 0;
182 enum ip_conntrack_info ctinfo;
183 struct nf_conn *ct;
184 struct net *net;
185
186#ifdef CONFIG_IP_VS_IPV6
187
188
189
190 if (cp->af == AF_INET6)
191 return 1;
192#endif
193
194 *diff = 0;
195
196
197 if (cp->state != IP_VS_TCP_S_ESTABLISHED)
198 return 1;
199
200
201 if (!skb_make_writable(skb, skb->len))
202 return 0;
203
204 if (cp->app_data == &ip_vs_ftp_pasv) {
205 iph = ip_hdr(skb);
206 th = (struct tcphdr *)&(((char *)iph)[iph->ihl*4]);
207 data = (char *)th + (th->doff << 2);
208 data_limit = skb_tail_pointer(skb);
209
210 if (ip_vs_ftp_get_addrport(data, data_limit,
211 SERVER_STRING,
212 sizeof(SERVER_STRING)-1,
213 '(', ')',
214 &from.ip, &port,
215 &start, &end) != 1)
216 return 1;
217
218 IP_VS_DBG(7, "PASV response (%pI4:%d) -> %pI4:%d detected\n",
219 &from.ip, ntohs(port), &cp->caddr.ip, 0);
220
221
222
223
224 {
225 struct ip_vs_conn_param p;
226 ip_vs_conn_fill_param(ip_vs_conn_net(cp), AF_INET,
227 iph->protocol, &from, port,
228 &cp->caddr, 0, &p);
229 n_cp = ip_vs_conn_out_get(&p);
230 }
231 if (!n_cp) {
232 struct ip_vs_conn_param p;
233 ip_vs_conn_fill_param(ip_vs_conn_net(cp),
234 AF_INET, IPPROTO_TCP, &cp->caddr,
235 0, &cp->vaddr, port, &p);
236 n_cp = ip_vs_conn_new(&p, &from, port,
237 IP_VS_CONN_F_NO_CPORT |
238 IP_VS_CONN_F_NFCT,
239 cp->dest, skb->mark);
240 if (!n_cp)
241 return 0;
242
243
244 ip_vs_control_add(n_cp, cp);
245 }
246
247
248
249
250 from.ip = n_cp->vaddr.ip;
251 port = n_cp->vport;
252 snprintf(buf, sizeof(buf), "%u,%u,%u,%u,%u,%u",
253 ((unsigned char *)&from.ip)[0],
254 ((unsigned char *)&from.ip)[1],
255 ((unsigned char *)&from.ip)[2],
256 ((unsigned char *)&from.ip)[3],
257 ntohs(port) >> 8,
258 ntohs(port) & 0xFF);
259
260 buf_len = strlen(buf);
261
262 ct = nf_ct_get(skb, &ctinfo);
263 if (ct && !nf_ct_is_untracked(ct) && nfct_nat(ct)) {
264
265
266
267
268
269
270 rcu_read_lock();
271 ret = nf_nat_mangle_tcp_packet(skb, ct, ctinfo,
272 iph->ihl * 4,
273 start-data, end-start,
274 buf, buf_len);
275 rcu_read_unlock();
276 if (ret) {
277 ip_vs_nfct_expect_related(skb, ct, n_cp,
278 IPPROTO_TCP, 0, 0);
279 if (skb->ip_summed == CHECKSUM_COMPLETE)
280 skb->ip_summed = CHECKSUM_UNNECESSARY;
281
282 ret = 1;
283 }
284 }
285
286
287
288
289
290
291 net = skb_net(skb);
292 cp->app_data = NULL;
293 ip_vs_tcp_conn_listen(net, n_cp);
294 ip_vs_conn_put(n_cp);
295 return ret;
296 }
297 return 1;
298}
299
300
301
302
303
304
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306
307
308
309
310
311
312static int ip_vs_ftp_in(struct ip_vs_app *app, struct ip_vs_conn *cp,
313 struct sk_buff *skb, int *diff)
314{
315 struct iphdr *iph;
316 struct tcphdr *th;
317 char *data, *data_start, *data_limit;
318 char *start, *end;
319 union nf_inet_addr to;
320 __be16 port;
321 struct ip_vs_conn *n_cp;
322 struct net *net;
323
324#ifdef CONFIG_IP_VS_IPV6
325
326
327
328 if (cp->af == AF_INET6)
329 return 1;
330#endif
331
332
333 *diff = 0;
334
335
336 if (cp->state != IP_VS_TCP_S_ESTABLISHED)
337 return 1;
338
339
340 if (!skb_make_writable(skb, skb->len))
341 return 0;
342
343
344
345
346 iph = ip_hdr(skb);
347 th = (struct tcphdr *)&(((char *)iph)[iph->ihl*4]);
348
349
350
351
352 data = data_start = (char *)th + (th->doff << 2);
353 data_limit = skb_tail_pointer(skb);
354
355 while (data <= data_limit - 6) {
356 if (strnicmp(data, "PASV\r\n", 6) == 0) {
357
358 IP_VS_DBG(7, "got PASV at %td of %td\n",
359 data - data_start,
360 data_limit - data_start);
361 cp->app_data = &ip_vs_ftp_pasv;
362 return 1;
363 }
364 data++;
365 }
366
367
368
369
370
371
372
373
374 if (ip_vs_ftp_get_addrport(data_start, data_limit,
375 CLIENT_STRING, sizeof(CLIENT_STRING)-1,
376 ' ', '\r', &to.ip, &port,
377 &start, &end) != 1)
378 return 1;
379
380 IP_VS_DBG(7, "PORT %pI4:%d detected\n", &to.ip, ntohs(port));
381
382
383 cp->app_data = NULL;
384
385
386
387
388 IP_VS_DBG(7, "protocol %s %pI4:%d %pI4:%d\n",
389 ip_vs_proto_name(iph->protocol),
390 &to.ip, ntohs(port), &cp->vaddr.ip, 0);
391
392 {
393 struct ip_vs_conn_param p;
394 ip_vs_conn_fill_param(ip_vs_conn_net(cp), AF_INET,
395 iph->protocol, &to, port, &cp->vaddr,
396 htons(ntohs(cp->vport)-1), &p);
397 n_cp = ip_vs_conn_in_get(&p);
398 if (!n_cp) {
399 n_cp = ip_vs_conn_new(&p, &cp->daddr,
400 htons(ntohs(cp->dport)-1),
401 IP_VS_CONN_F_NFCT, cp->dest,
402 skb->mark);
403 if (!n_cp)
404 return 0;
405
406
407 ip_vs_control_add(n_cp, cp);
408 }
409 }
410
411
412
413
414 net = skb_net(skb);
415 ip_vs_tcp_conn_listen(net, n_cp);
416 ip_vs_conn_put(n_cp);
417
418 return 1;
419}
420
421
422static struct ip_vs_app ip_vs_ftp = {
423 .name = "ftp",
424 .type = IP_VS_APP_TYPE_FTP,
425 .protocol = IPPROTO_TCP,
426 .module = THIS_MODULE,
427 .incs_list = LIST_HEAD_INIT(ip_vs_ftp.incs_list),
428 .init_conn = ip_vs_ftp_init_conn,
429 .done_conn = ip_vs_ftp_done_conn,
430 .bind_conn = NULL,
431 .unbind_conn = NULL,
432 .pkt_out = ip_vs_ftp_out,
433 .pkt_in = ip_vs_ftp_in,
434};
435
436
437
438
439static int __net_init __ip_vs_ftp_init(struct net *net)
440{
441 int i, ret;
442 struct ip_vs_app *app;
443 struct netns_ipvs *ipvs = net_ipvs(net);
444
445 if (!ipvs)
446 return -ENOENT;
447
448 app = register_ip_vs_app(net, &ip_vs_ftp);
449 if (IS_ERR(app))
450 return PTR_ERR(app);
451
452 for (i = 0; i < ports_count; i++) {
453 if (!ports[i])
454 continue;
455 ret = register_ip_vs_app_inc(net, app, app->protocol, ports[i]);
456 if (ret)
457 goto err_unreg;
458 pr_info("%s: loaded support on port[%d] = %d\n",
459 app->name, i, ports[i]);
460 }
461 return 0;
462
463err_unreg:
464 unregister_ip_vs_app(net, &ip_vs_ftp);
465 return ret;
466}
467
468
469
470static void __ip_vs_ftp_exit(struct net *net)
471{
472 unregister_ip_vs_app(net, &ip_vs_ftp);
473}
474
475static struct pernet_operations ip_vs_ftp_ops = {
476 .init = __ip_vs_ftp_init,
477 .exit = __ip_vs_ftp_exit,
478};
479
480static int __init ip_vs_ftp_init(void)
481{
482 int rv;
483
484 rv = register_pernet_subsys(&ip_vs_ftp_ops);
485
486 return rv;
487}
488
489
490
491
492static void __exit ip_vs_ftp_exit(void)
493{
494 unregister_pernet_subsys(&ip_vs_ftp_ops);
495
496}
497
498
499module_init(ip_vs_ftp_init);
500module_exit(ip_vs_ftp_exit);
501MODULE_LICENSE("GPL");
502