Commit | Line | Data |
---|---|---|
9fb9cbb1 YK |
1 | /* FTP extension for connection tracking. */ |
2 | ||
3 | /* (C) 1999-2001 Paul `Rusty' Russell | |
4 | * (C) 2002-2004 Netfilter Core Team <coreteam@netfilter.org> | |
5 | * (C) 2003,2004 USAGI/WIDE Project <http://www.linux-ipv6.org> | |
6 | * | |
7 | * This program is free software; you can redistribute it and/or modify | |
8 | * it under the terms of the GNU General Public License version 2 as | |
9 | * published by the Free Software Foundation. | |
9fb9cbb1 YK |
10 | */ |
11 | ||
9fb9cbb1 YK |
12 | #include <linux/module.h> |
13 | #include <linux/moduleparam.h> | |
14 | #include <linux/netfilter.h> | |
15 | #include <linux/ip.h> | |
5a0e3ad6 | 16 | #include <linux/slab.h> |
9fb9cbb1 YK |
17 | #include <linux/ipv6.h> |
18 | #include <linux/ctype.h> | |
6a28ec8c | 19 | #include <linux/inet.h> |
9fb9cbb1 YK |
20 | #include <net/checksum.h> |
21 | #include <net/tcp.h> | |
22 | ||
23 | #include <net/netfilter/nf_conntrack.h> | |
77ab9cff | 24 | #include <net/netfilter/nf_conntrack_expect.h> |
f6180121 | 25 | #include <net/netfilter/nf_conntrack_ecache.h> |
9fb9cbb1 YK |
26 | #include <net/netfilter/nf_conntrack_helper.h> |
27 | #include <linux/netfilter/nf_conntrack_ftp.h> | |
28 | ||
29 | MODULE_LICENSE("GPL"); | |
30 | MODULE_AUTHOR("Rusty Russell <rusty@rustcorp.com.au>"); | |
31 | MODULE_DESCRIPTION("ftp connection tracking helper"); | |
d2483dde | 32 | MODULE_ALIAS("ip_conntrack_ftp"); |
4dc06f96 | 33 | MODULE_ALIAS_NFCT_HELPER("ftp"); |
9fb9cbb1 YK |
34 | |
35 | /* This is slow, but it's simple. --RR */ | |
36 | static char *ftp_buffer; | |
37 | ||
38 | static DEFINE_SPINLOCK(nf_ftp_lock); | |
39 | ||
40 | #define MAX_PORTS 8 | |
41 | static u_int16_t ports[MAX_PORTS]; | |
42 | static unsigned int ports_c; | |
43 | module_param_array(ports, ushort, &ports_c, 0400); | |
44 | ||
eb939922 | 45 | static bool loose; |
e7be6994 | 46 | module_param(loose, bool, 0600); |
9fb9cbb1 | 47 | |
3db05fea | 48 | unsigned int (*nf_nat_ftp_hook)(struct sk_buff *skb, |
9fb9cbb1 | 49 | enum ip_conntrack_info ctinfo, |
55a73324 | 50 | enum nf_ct_ftp_type type, |
051966c0 | 51 | unsigned int protoff, |
9fb9cbb1 YK |
52 | unsigned int matchoff, |
53 | unsigned int matchlen, | |
25b86e05 | 54 | struct nf_conntrack_expect *exp); |
9fb9cbb1 YK |
55 | EXPORT_SYMBOL_GPL(nf_nat_ftp_hook); |
56 | ||
9fb9cbb1 YK |
57 | static int try_rfc959(const char *, size_t, struct nf_conntrack_man *, char); |
58 | static int try_eprt(const char *, size_t, struct nf_conntrack_man *, char); | |
59 | static int try_epsv_response(const char *, size_t, struct nf_conntrack_man *, | |
60 | char); | |
61 | ||
62 | static struct ftp_search { | |
9fb9cbb1 YK |
63 | const char *pattern; |
64 | size_t plen; | |
65 | char skip; | |
66 | char term; | |
55a73324 | 67 | enum nf_ct_ftp_type ftptype; |
9fb9cbb1 | 68 | int (*getnum)(const char *, size_t, struct nf_conntrack_man *, char); |
7d8c5018 PM |
69 | } search[IP_CT_DIR_MAX][2] = { |
70 | [IP_CT_DIR_ORIGINAL] = { | |
71 | { | |
72 | .pattern = "PORT", | |
73 | .plen = sizeof("PORT") - 1, | |
74 | .skip = ' ', | |
75 | .term = '\r', | |
55a73324 | 76 | .ftptype = NF_CT_FTP_PORT, |
7d8c5018 PM |
77 | .getnum = try_rfc959, |
78 | }, | |
79 | { | |
80 | .pattern = "EPRT", | |
81 | .plen = sizeof("EPRT") - 1, | |
82 | .skip = ' ', | |
83 | .term = '\r', | |
55a73324 | 84 | .ftptype = NF_CT_FTP_EPRT, |
7d8c5018 PM |
85 | .getnum = try_eprt, |
86 | }, | |
9fb9cbb1 | 87 | }, |
7d8c5018 PM |
88 | [IP_CT_DIR_REPLY] = { |
89 | { | |
90 | .pattern = "227 ", | |
91 | .plen = sizeof("227 ") - 1, | |
92 | .skip = '(', | |
93 | .term = ')', | |
55a73324 | 94 | .ftptype = NF_CT_FTP_PASV, |
7d8c5018 PM |
95 | .getnum = try_rfc959, |
96 | }, | |
97 | { | |
98 | .pattern = "229 ", | |
99 | .plen = sizeof("229 ") - 1, | |
100 | .skip = '(', | |
101 | .term = ')', | |
55a73324 | 102 | .ftptype = NF_CT_FTP_EPSV, |
7d8c5018 PM |
103 | .getnum = try_epsv_response, |
104 | }, | |
9fb9cbb1 YK |
105 | }, |
106 | }; | |
107 | ||
9fb9cbb1 YK |
108 | static int |
109 | get_ipv6_addr(const char *src, size_t dlen, struct in6_addr *dst, u_int8_t term) | |
110 | { | |
6a28ec8c DM |
111 | const char *end; |
112 | int ret = in6_pton(src, min_t(size_t, dlen, 0xffff), (u8 *)dst, term, &end); | |
1884f78c YH |
113 | if (ret > 0) |
114 | return (int)(end - src); | |
115 | return 0; | |
9fb9cbb1 YK |
116 | } |
117 | ||
118 | static int try_number(const char *data, size_t dlen, u_int32_t array[], | |
601e68e1 | 119 | int array_size, char sep, char term) |
9fb9cbb1 YK |
120 | { |
121 | u_int32_t i, len; | |
122 | ||
123 | memset(array, 0, sizeof(array[0])*array_size); | |
124 | ||
125 | /* Keep data pointing at next char. */ | |
126 | for (i = 0, len = 0; len < dlen && i < array_size; len++, data++) { | |
127 | if (*data >= '0' && *data <= '9') { | |
128 | array[i] = array[i]*10 + *data - '0'; | |
129 | } | |
130 | else if (*data == sep) | |
131 | i++; | |
132 | else { | |
133 | /* Unexpected character; true if it's the | |
134 | terminator and we're finished. */ | |
135 | if (*data == term && i == array_size - 1) | |
136 | return len; | |
137 | ||
0d53778e PM |
138 | pr_debug("Char %u (got %u nums) `%u' unexpected\n", |
139 | len, i, *data); | |
9fb9cbb1 YK |
140 | return 0; |
141 | } | |
142 | } | |
0d53778e PM |
143 | pr_debug("Failed to fill %u numbers separated by %c\n", |
144 | array_size, sep); | |
9fb9cbb1 YK |
145 | return 0; |
146 | } | |
147 | ||
148 | /* Returns 0, or length of numbers: 192,168,1,1,5,6 */ | |
149 | static int try_rfc959(const char *data, size_t dlen, | |
150 | struct nf_conntrack_man *cmd, char term) | |
151 | { | |
152 | int length; | |
153 | u_int32_t array[6]; | |
154 | ||
155 | length = try_number(data, dlen, array, 6, ',', term); | |
156 | if (length == 0) | |
157 | return 0; | |
158 | ||
159 | cmd->u3.ip = htonl((array[0] << 24) | (array[1] << 16) | | |
160 | (array[2] << 8) | array[3]); | |
161 | cmd->u.tcp.port = htons((array[4] << 8) | array[5]); | |
162 | return length; | |
163 | } | |
164 | ||
165 | /* Grab port: number up to delimiter */ | |
166 | static int get_port(const char *data, int start, size_t dlen, char delim, | |
bff9a89b | 167 | __be16 *port) |
9fb9cbb1 YK |
168 | { |
169 | u_int16_t tmp_port = 0; | |
170 | int i; | |
171 | ||
172 | for (i = start; i < dlen; i++) { | |
173 | /* Finished? */ | |
174 | if (data[i] == delim) { | |
175 | if (tmp_port == 0) | |
176 | break; | |
177 | *port = htons(tmp_port); | |
0d53778e | 178 | pr_debug("get_port: return %d\n", tmp_port); |
9fb9cbb1 YK |
179 | return i + 1; |
180 | } | |
181 | else if (data[i] >= '0' && data[i] <= '9') | |
182 | tmp_port = tmp_port*10 + data[i] - '0'; | |
183 | else { /* Some other crap */ | |
0d53778e | 184 | pr_debug("get_port: invalid char.\n"); |
9fb9cbb1 YK |
185 | break; |
186 | } | |
187 | } | |
188 | return 0; | |
189 | } | |
190 | ||
191 | /* Returns 0, or length of numbers: |1|132.235.1.2|6275| or |2|3ffe::1|6275| */ | |
192 | static int try_eprt(const char *data, size_t dlen, struct nf_conntrack_man *cmd, | |
193 | char term) | |
194 | { | |
195 | char delim; | |
196 | int length; | |
197 | ||
198 | /* First character is delimiter, then "1" for IPv4 or "2" for IPv6, | |
199 | then delimiter again. */ | |
200 | if (dlen <= 3) { | |
0d53778e | 201 | pr_debug("EPRT: too short\n"); |
9fb9cbb1 YK |
202 | return 0; |
203 | } | |
204 | delim = data[0]; | |
205 | if (isdigit(delim) || delim < 33 || delim > 126 || data[2] != delim) { | |
0d53778e | 206 | pr_debug("try_eprt: invalid delimitter.\n"); |
9fb9cbb1 YK |
207 | return 0; |
208 | } | |
209 | ||
210 | if ((cmd->l3num == PF_INET && data[1] != '1') || | |
211 | (cmd->l3num == PF_INET6 && data[1] != '2')) { | |
0d53778e | 212 | pr_debug("EPRT: invalid protocol number.\n"); |
9fb9cbb1 YK |
213 | return 0; |
214 | } | |
215 | ||
0d53778e | 216 | pr_debug("EPRT: Got %c%c%c\n", delim, data[1], delim); |
9fb9cbb1 YK |
217 | |
218 | if (data[1] == '1') { | |
219 | u_int32_t array[4]; | |
220 | ||
221 | /* Now we have IP address. */ | |
222 | length = try_number(data + 3, dlen - 3, array, 4, '.', delim); | |
223 | if (length != 0) | |
224 | cmd->u3.ip = htonl((array[0] << 24) | (array[1] << 16) | |
225 | | (array[2] << 8) | array[3]); | |
226 | } else { | |
227 | /* Now we have IPv6 address. */ | |
228 | length = get_ipv6_addr(data + 3, dlen - 3, | |
229 | (struct in6_addr *)cmd->u3.ip6, delim); | |
230 | } | |
231 | ||
232 | if (length == 0) | |
233 | return 0; | |
0d53778e | 234 | pr_debug("EPRT: Got IP address!\n"); |
9fb9cbb1 YK |
235 | /* Start offset includes initial "|1|", and trailing delimiter */ |
236 | return get_port(data, 3 + length + 1, dlen, delim, &cmd->u.tcp.port); | |
237 | } | |
238 | ||
239 | /* Returns 0, or length of numbers: |||6446| */ | |
240 | static int try_epsv_response(const char *data, size_t dlen, | |
241 | struct nf_conntrack_man *cmd, char term) | |
242 | { | |
243 | char delim; | |
244 | ||
245 | /* Three delimiters. */ | |
246 | if (dlen <= 3) return 0; | |
247 | delim = data[0]; | |
f64f9e71 JP |
248 | if (isdigit(delim) || delim < 33 || delim > 126 || |
249 | data[1] != delim || data[2] != delim) | |
9fb9cbb1 YK |
250 | return 0; |
251 | ||
252 | return get_port(data, 3, dlen, delim, &cmd->u.tcp.port); | |
253 | } | |
254 | ||
255 | /* Return 1 for match, 0 for accept, -1 for partial. */ | |
256 | static int find_pattern(const char *data, size_t dlen, | |
257 | const char *pattern, size_t plen, | |
258 | char skip, char term, | |
259 | unsigned int *numoff, | |
260 | unsigned int *numlen, | |
261 | struct nf_conntrack_man *cmd, | |
262 | int (*getnum)(const char *, size_t, | |
263 | struct nf_conntrack_man *, char)) | |
264 | { | |
265 | size_t i; | |
266 | ||
0d53778e | 267 | pr_debug("find_pattern `%s': dlen = %Zu\n", pattern, dlen); |
9fb9cbb1 YK |
268 | if (dlen == 0) |
269 | return 0; | |
270 | ||
271 | if (dlen <= plen) { | |
272 | /* Short packet: try for partial? */ | |
273 | if (strnicmp(data, pattern, dlen) == 0) | |
274 | return -1; | |
275 | else return 0; | |
276 | } | |
277 | ||
278 | if (strnicmp(data, pattern, plen) != 0) { | |
279 | #if 0 | |
280 | size_t i; | |
281 | ||
0d53778e | 282 | pr_debug("ftp: string mismatch\n"); |
9fb9cbb1 | 283 | for (i = 0; i < plen; i++) { |
0d53778e PM |
284 | pr_debug("ftp:char %u `%c'(%u) vs `%c'(%u)\n", |
285 | i, data[i], data[i], | |
286 | pattern[i], pattern[i]); | |
9fb9cbb1 YK |
287 | } |
288 | #endif | |
289 | return 0; | |
290 | } | |
291 | ||
0d53778e | 292 | pr_debug("Pattern matches!\n"); |
9fb9cbb1 YK |
293 | /* Now we've found the constant string, try to skip |
294 | to the 'skip' character */ | |
295 | for (i = plen; data[i] != skip; i++) | |
296 | if (i == dlen - 1) return -1; | |
297 | ||
298 | /* Skip over the last character */ | |
299 | i++; | |
300 | ||
0d53778e | 301 | pr_debug("Skipped up to `%c'!\n", skip); |
9fb9cbb1 YK |
302 | |
303 | *numoff = i; | |
304 | *numlen = getnum(data + i, dlen - i, cmd, term); | |
305 | if (!*numlen) | |
306 | return -1; | |
307 | ||
0d53778e | 308 | pr_debug("Match succeeded!\n"); |
9fb9cbb1 YK |
309 | return 1; |
310 | } | |
311 | ||
312 | /* Look up to see if we're just after a \n. */ | |
55a73324 | 313 | static int find_nl_seq(u32 seq, const struct nf_ct_ftp_master *info, int dir) |
9fb9cbb1 YK |
314 | { |
315 | unsigned int i; | |
316 | ||
317 | for (i = 0; i < info->seq_aft_nl_num[dir]; i++) | |
318 | if (info->seq_aft_nl[dir][i] == seq) | |
319 | return 1; | |
320 | return 0; | |
321 | } | |
322 | ||
323 | /* We don't update if it's older than what we have. */ | |
a71996fc AD |
324 | static void update_nl_seq(struct nf_conn *ct, u32 nl_seq, |
325 | struct nf_ct_ftp_master *info, int dir, | |
9fb9cbb1 YK |
326 | struct sk_buff *skb) |
327 | { | |
aaff23a9 | 328 | unsigned int i, oldest; |
9fb9cbb1 YK |
329 | |
330 | /* Look for oldest: if we find exact match, we're done. */ | |
331 | for (i = 0; i < info->seq_aft_nl_num[dir]; i++) { | |
332 | if (info->seq_aft_nl[dir][i] == nl_seq) | |
333 | return; | |
9fb9cbb1 YK |
334 | } |
335 | ||
336 | if (info->seq_aft_nl_num[dir] < NUM_SEQ_TO_REMEMBER) { | |
337 | info->seq_aft_nl[dir][info->seq_aft_nl_num[dir]++] = nl_seq; | |
aaff23a9 PM |
338 | } else { |
339 | if (before(info->seq_aft_nl[dir][0], info->seq_aft_nl[dir][1])) | |
340 | oldest = 0; | |
341 | else | |
342 | oldest = 1; | |
343 | ||
344 | if (after(nl_seq, info->seq_aft_nl[dir][oldest])) | |
345 | info->seq_aft_nl[dir][oldest] = nl_seq; | |
9fb9cbb1 YK |
346 | } |
347 | } | |
348 | ||
3db05fea | 349 | static int help(struct sk_buff *skb, |
9fb9cbb1 YK |
350 | unsigned int protoff, |
351 | struct nf_conn *ct, | |
352 | enum ip_conntrack_info ctinfo) | |
353 | { | |
354 | unsigned int dataoff, datalen; | |
58c0fb0d JE |
355 | const struct tcphdr *th; |
356 | struct tcphdr _tcph; | |
357 | const char *fb_ptr; | |
9fb9cbb1 YK |
358 | int ret; |
359 | u32 seq; | |
360 | int dir = CTINFO2DIR(ctinfo); | |
d6e8cc6c | 361 | unsigned int uninitialized_var(matchlen), uninitialized_var(matchoff); |
1afc5679 | 362 | struct nf_ct_ftp_master *ct_ftp_info = nfct_help_data(ct); |
9fb9cbb1 | 363 | struct nf_conntrack_expect *exp; |
643a2c15 | 364 | union nf_inet_addr *daddr; |
9fb9cbb1 | 365 | struct nf_conntrack_man cmd = {}; |
9fb9cbb1 YK |
366 | unsigned int i; |
367 | int found = 0, ends_in_nl; | |
337fbc41 | 368 | typeof(nf_nat_ftp_hook) nf_nat_ftp; |
9fb9cbb1 YK |
369 | |
370 | /* Until there's been traffic both ways, don't look in packets. */ | |
f64f9e71 | 371 | if (ctinfo != IP_CT_ESTABLISHED && |
fb048833 | 372 | ctinfo != IP_CT_ESTABLISHED_REPLY) { |
0d53778e | 373 | pr_debug("ftp: Conntrackinfo = %u\n", ctinfo); |
9fb9cbb1 YK |
374 | return NF_ACCEPT; |
375 | } | |
376 | ||
3db05fea | 377 | th = skb_header_pointer(skb, protoff, sizeof(_tcph), &_tcph); |
9fb9cbb1 YK |
378 | if (th == NULL) |
379 | return NF_ACCEPT; | |
380 | ||
381 | dataoff = protoff + th->doff * 4; | |
382 | /* No data? */ | |
3db05fea | 383 | if (dataoff >= skb->len) { |
0d53778e | 384 | pr_debug("ftp: dataoff(%u) >= skblen(%u)\n", dataoff, |
3db05fea | 385 | skb->len); |
9fb9cbb1 YK |
386 | return NF_ACCEPT; |
387 | } | |
3db05fea | 388 | datalen = skb->len - dataoff; |
9fb9cbb1 YK |
389 | |
390 | spin_lock_bh(&nf_ftp_lock); | |
3db05fea | 391 | fb_ptr = skb_header_pointer(skb, dataoff, datalen, ftp_buffer); |
9fb9cbb1 YK |
392 | BUG_ON(fb_ptr == NULL); |
393 | ||
394 | ends_in_nl = (fb_ptr[datalen - 1] == '\n'); | |
395 | seq = ntohl(th->seq) + datalen; | |
396 | ||
397 | /* Look up to see if we're just after a \n. */ | |
398 | if (!find_nl_seq(ntohl(th->seq), ct_ftp_info, dir)) { | |
7be54ca4 PNA |
399 | /* We're picking up this, clear flags and let it continue */ |
400 | if (unlikely(ct_ftp_info->flags[dir] & NF_CT_FTP_SEQ_PICKUP)) { | |
401 | ct_ftp_info->flags[dir] ^= NF_CT_FTP_SEQ_PICKUP; | |
402 | goto skip_nl_seq; | |
403 | } | |
404 | ||
9fb9cbb1 | 405 | /* Now if this ends in \n, update ftp info. */ |
0d53778e PM |
406 | pr_debug("nf_conntrack_ftp: wrong seq pos %s(%u) or %s(%u)\n", |
407 | ct_ftp_info->seq_aft_nl_num[dir] > 0 ? "" : "(UNSET)", | |
408 | ct_ftp_info->seq_aft_nl[dir][0], | |
409 | ct_ftp_info->seq_aft_nl_num[dir] > 1 ? "" : "(UNSET)", | |
410 | ct_ftp_info->seq_aft_nl[dir][1]); | |
9fb9cbb1 YK |
411 | ret = NF_ACCEPT; |
412 | goto out_update_nl; | |
413 | } | |
414 | ||
7be54ca4 | 415 | skip_nl_seq: |
601e68e1 YH |
416 | /* Initialize IP/IPv6 addr to expected address (it's not mentioned |
417 | in EPSV responses) */ | |
5e8fbe2a | 418 | cmd.l3num = nf_ct_l3num(ct); |
9fb9cbb1 YK |
419 | memcpy(cmd.u3.all, &ct->tuplehash[dir].tuple.src.u3.all, |
420 | sizeof(cmd.u3.all)); | |
421 | ||
7d8c5018 | 422 | for (i = 0; i < ARRAY_SIZE(search[dir]); i++) { |
9fb9cbb1 | 423 | found = find_pattern(fb_ptr, datalen, |
7d8c5018 PM |
424 | search[dir][i].pattern, |
425 | search[dir][i].plen, | |
426 | search[dir][i].skip, | |
427 | search[dir][i].term, | |
9fb9cbb1 YK |
428 | &matchoff, &matchlen, |
429 | &cmd, | |
7d8c5018 | 430 | search[dir][i].getnum); |
9fb9cbb1 YK |
431 | if (found) break; |
432 | } | |
433 | if (found == -1) { | |
434 | /* We don't usually drop packets. After all, this is | |
435 | connection tracking, not packet filtering. | |
436 | However, it is necessary for accurate tracking in | |
437 | this case. */ | |
4813eadf PM |
438 | pr_debug("conntrack_ftp: partial %s %u+%u\n", |
439 | search[dir][i].pattern, ntohl(th->seq), datalen); | |
9fb9cbb1 YK |
440 | ret = NF_DROP; |
441 | goto out; | |
442 | } else if (found == 0) { /* No match */ | |
443 | ret = NF_ACCEPT; | |
444 | goto out_update_nl; | |
445 | } | |
446 | ||
0d53778e PM |
447 | pr_debug("conntrack_ftp: match `%.*s' (%u bytes at %u)\n", |
448 | matchlen, fb_ptr + matchoff, | |
449 | matchlen, ntohl(th->seq) + matchoff); | |
9fb9cbb1 | 450 | |
6823645d | 451 | exp = nf_ct_expect_alloc(ct); |
9fb9cbb1 YK |
452 | if (exp == NULL) { |
453 | ret = NF_DROP; | |
454 | goto out; | |
455 | } | |
456 | ||
457 | /* We refer to the reverse direction ("!dir") tuples here, | |
458 | * because we're expecting something in the other direction. | |
459 | * Doesn't matter unless NAT is happening. */ | |
df43b4e7 | 460 | daddr = &ct->tuplehash[!dir].tuple.dst.u3; |
9fb9cbb1 YK |
461 | |
462 | /* Update the ftp info */ | |
5e8fbe2a | 463 | if ((cmd.l3num == nf_ct_l3num(ct)) && |
9fb9cbb1 YK |
464 | memcmp(&cmd.u3.all, &ct->tuplehash[dir].tuple.src.u3.all, |
465 | sizeof(cmd.u3.all))) { | |
466 | /* Enrico Scholz's passive FTP to partially RNAT'd ftp | |
601e68e1 YH |
467 | server: it really wants us to connect to a |
468 | different IP address. Simply don't record it for | |
469 | NAT. */ | |
9fb9cbb1 | 470 | if (cmd.l3num == PF_INET) { |
14d5e834 HH |
471 | pr_debug("conntrack_ftp: NOT RECORDING: %pI4 != %pI4\n", |
472 | &cmd.u3.ip, | |
473 | &ct->tuplehash[dir].tuple.src.u3.ip); | |
9fb9cbb1 | 474 | } else { |
5b095d98 | 475 | pr_debug("conntrack_ftp: NOT RECORDING: %pI6 != %pI6\n", |
38ff4fa4 HH |
476 | cmd.u3.ip6, |
477 | ct->tuplehash[dir].tuple.src.u3.ip6); | |
9fb9cbb1 YK |
478 | } |
479 | ||
480 | /* Thanks to Cristiano Lincoln Mattos | |
481 | <lincoln@cesar.org.br> for reporting this potential | |
482 | problem (DMZ machines opening holes to internal | |
483 | networks, or the packet filter itself). */ | |
484 | if (!loose) { | |
485 | ret = NF_ACCEPT; | |
486 | goto out_put_expect; | |
487 | } | |
df43b4e7 | 488 | daddr = &cmd.u3; |
9fb9cbb1 YK |
489 | } |
490 | ||
6002f266 | 491 | nf_ct_expect_init(exp, NF_CT_EXPECT_CLASS_DEFAULT, cmd.l3num, |
df43b4e7 PM |
492 | &ct->tuplehash[!dir].tuple.src.u3, daddr, |
493 | IPPROTO_TCP, NULL, &cmd.u.tcp.port); | |
9fb9cbb1 YK |
494 | |
495 | /* Now, NAT might want to mangle the packet, and register the | |
496 | * (possibly changed) expectation itself. */ | |
337fbc41 | 497 | nf_nat_ftp = rcu_dereference(nf_nat_ftp_hook); |
d33cbeeb | 498 | if (nf_nat_ftp && ct->status & IPS_NAT_MASK) |
3db05fea | 499 | ret = nf_nat_ftp(skb, ctinfo, search[dir][i].ftptype, |
051966c0 | 500 | protoff, matchoff, matchlen, exp); |
9fb9cbb1 YK |
501 | else { |
502 | /* Can't expect this? Best to drop packet now. */ | |
6823645d | 503 | if (nf_ct_expect_related(exp) != 0) |
9fb9cbb1 YK |
504 | ret = NF_DROP; |
505 | else | |
506 | ret = NF_ACCEPT; | |
507 | } | |
508 | ||
509 | out_put_expect: | |
6823645d | 510 | nf_ct_expect_put(exp); |
9fb9cbb1 YK |
511 | |
512 | out_update_nl: | |
513 | /* Now if this ends in \n, update ftp info. Seq may have been | |
514 | * adjusted by NAT code. */ | |
515 | if (ends_in_nl) | |
a71996fc | 516 | update_nl_seq(ct, seq, ct_ftp_info, dir, skb); |
9fb9cbb1 YK |
517 | out: |
518 | spin_unlock_bh(&nf_ftp_lock); | |
519 | return ret; | |
520 | } | |
521 | ||
7be54ca4 PNA |
522 | static int nf_ct_ftp_from_nlattr(struct nlattr *attr, struct nf_conn *ct) |
523 | { | |
524 | struct nf_ct_ftp_master *ftp = nfct_help_data(ct); | |
525 | ||
526 | /* This conntrack has been injected from user-space, always pick up | |
527 | * sequence tracking. Otherwise, the first FTP command after the | |
528 | * failover breaks. | |
529 | */ | |
530 | ftp->flags[IP_CT_DIR_ORIGINAL] |= NF_CT_FTP_SEQ_PICKUP; | |
531 | ftp->flags[IP_CT_DIR_REPLY] |= NF_CT_FTP_SEQ_PICKUP; | |
532 | return 0; | |
533 | } | |
534 | ||
ec59a111 | 535 | static struct nf_conntrack_helper ftp[MAX_PORTS][2] __read_mostly; |
9fb9cbb1 | 536 | |
6002f266 PM |
537 | static const struct nf_conntrack_expect_policy ftp_exp_policy = { |
538 | .max_expected = 1, | |
539 | .timeout = 5 * 60, | |
540 | }; | |
541 | ||
9fb9cbb1 | 542 | /* don't make this __exit, since it's called from __init ! */ |
65b4b4e8 | 543 | static void nf_conntrack_ftp_fini(void) |
9fb9cbb1 YK |
544 | { |
545 | int i, j; | |
546 | for (i = 0; i < ports_c; i++) { | |
547 | for (j = 0; j < 2; j++) { | |
548 | if (ftp[i][j].me == NULL) | |
549 | continue; | |
550 | ||
0d53778e PM |
551 | pr_debug("nf_ct_ftp: unregistering helper for pf: %d " |
552 | "port: %d\n", | |
553 | ftp[i][j].tuple.src.l3num, ports[i]); | |
9fb9cbb1 YK |
554 | nf_conntrack_helper_unregister(&ftp[i][j]); |
555 | } | |
556 | } | |
557 | ||
558 | kfree(ftp_buffer); | |
559 | } | |
560 | ||
65b4b4e8 | 561 | static int __init nf_conntrack_ftp_init(void) |
9fb9cbb1 YK |
562 | { |
563 | int i, j = -1, ret = 0; | |
9fb9cbb1 YK |
564 | |
565 | ftp_buffer = kmalloc(65536, GFP_KERNEL); | |
566 | if (!ftp_buffer) | |
567 | return -ENOMEM; | |
568 | ||
569 | if (ports_c == 0) | |
570 | ports[ports_c++] = FTP_PORT; | |
571 | ||
572 | /* FIXME should be configurable whether IPv4 and IPv6 FTP connections | |
573 | are tracked or not - YK */ | |
574 | for (i = 0; i < ports_c; i++) { | |
9fb9cbb1 YK |
575 | ftp[i][0].tuple.src.l3num = PF_INET; |
576 | ftp[i][1].tuple.src.l3num = PF_INET6; | |
577 | for (j = 0; j < 2; j++) { | |
1afc5679 | 578 | ftp[i][j].data_len = sizeof(struct nf_ct_ftp_master); |
9fb9cbb1 YK |
579 | ftp[i][j].tuple.src.u.tcp.port = htons(ports[i]); |
580 | ftp[i][j].tuple.dst.protonum = IPPROTO_TCP; | |
6002f266 | 581 | ftp[i][j].expect_policy = &ftp_exp_policy; |
9fb9cbb1 YK |
582 | ftp[i][j].me = THIS_MODULE; |
583 | ftp[i][j].help = help; | |
7be54ca4 | 584 | ftp[i][j].from_nlattr = nf_ct_ftp_from_nlattr; |
9fb9cbb1 | 585 | if (ports[i] == FTP_PORT) |
3a8fc53a | 586 | sprintf(ftp[i][j].name, "ftp"); |
9fb9cbb1 | 587 | else |
3a8fc53a | 588 | sprintf(ftp[i][j].name, "ftp-%d", ports[i]); |
9fb9cbb1 | 589 | |
0d53778e PM |
590 | pr_debug("nf_ct_ftp: registering helper for pf: %d " |
591 | "port: %d\n", | |
592 | ftp[i][j].tuple.src.l3num, ports[i]); | |
9fb9cbb1 YK |
593 | ret = nf_conntrack_helper_register(&ftp[i][j]); |
594 | if (ret) { | |
654d0fbd SH |
595 | printk(KERN_ERR "nf_ct_ftp: failed to register" |
596 | " helper for pf: %d port: %d\n", | |
9fb9cbb1 | 597 | ftp[i][j].tuple.src.l3num, ports[i]); |
65b4b4e8 | 598 | nf_conntrack_ftp_fini(); |
9fb9cbb1 YK |
599 | return ret; |
600 | } | |
601 | } | |
602 | } | |
603 | ||
604 | return 0; | |
605 | } | |
606 | ||
65b4b4e8 AM |
607 | module_init(nf_conntrack_ftp_init); |
608 | module_exit(nf_conntrack_ftp_fini); |