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> | |
f229f6ce | 6 | * (C) 2006-2012 Patrick McHardy <kaber@trash.net> |
9fb9cbb1 YK |
7 | * |
8 | * This program is free software; you can redistribute it and/or modify | |
9 | * it under the terms of the GNU General Public License version 2 as | |
10 | * published by the Free Software Foundation. | |
9fb9cbb1 YK |
11 | */ |
12 | ||
9fb9cbb1 YK |
13 | #include <linux/module.h> |
14 | #include <linux/moduleparam.h> | |
15 | #include <linux/netfilter.h> | |
16 | #include <linux/ip.h> | |
5a0e3ad6 | 17 | #include <linux/slab.h> |
9fb9cbb1 YK |
18 | #include <linux/ipv6.h> |
19 | #include <linux/ctype.h> | |
6a28ec8c | 20 | #include <linux/inet.h> |
9fb9cbb1 YK |
21 | #include <net/checksum.h> |
22 | #include <net/tcp.h> | |
23 | ||
24 | #include <net/netfilter/nf_conntrack.h> | |
77ab9cff | 25 | #include <net/netfilter/nf_conntrack_expect.h> |
f6180121 | 26 | #include <net/netfilter/nf_conntrack_ecache.h> |
9fb9cbb1 YK |
27 | #include <net/netfilter/nf_conntrack_helper.h> |
28 | #include <linux/netfilter/nf_conntrack_ftp.h> | |
29 | ||
30 | MODULE_LICENSE("GPL"); | |
31 | MODULE_AUTHOR("Rusty Russell <rusty@rustcorp.com.au>"); | |
32 | MODULE_DESCRIPTION("ftp connection tracking helper"); | |
d2483dde | 33 | MODULE_ALIAS("ip_conntrack_ftp"); |
4dc06f96 | 34 | MODULE_ALIAS_NFCT_HELPER("ftp"); |
9fb9cbb1 YK |
35 | |
36 | /* This is slow, but it's simple. --RR */ | |
37 | static char *ftp_buffer; | |
38 | ||
39 | static DEFINE_SPINLOCK(nf_ftp_lock); | |
40 | ||
41 | #define MAX_PORTS 8 | |
42 | static u_int16_t ports[MAX_PORTS]; | |
43 | static unsigned int ports_c; | |
44 | module_param_array(ports, ushort, &ports_c, 0400); | |
45 | ||
eb939922 | 46 | static bool loose; |
e7be6994 | 47 | module_param(loose, bool, 0600); |
9fb9cbb1 | 48 | |
3db05fea | 49 | unsigned int (*nf_nat_ftp_hook)(struct sk_buff *skb, |
9fb9cbb1 | 50 | enum ip_conntrack_info ctinfo, |
55a73324 | 51 | enum nf_ct_ftp_type type, |
051966c0 | 52 | unsigned int protoff, |
9fb9cbb1 YK |
53 | unsigned int matchoff, |
54 | unsigned int matchlen, | |
25b86e05 | 55 | struct nf_conntrack_expect *exp); |
9fb9cbb1 YK |
56 | EXPORT_SYMBOL_GPL(nf_nat_ftp_hook); |
57 | ||
9fb9cbb1 YK |
58 | static int try_rfc959(const char *, size_t, struct nf_conntrack_man *, char); |
59 | static int try_eprt(const char *, size_t, struct nf_conntrack_man *, char); | |
60 | static int try_epsv_response(const char *, size_t, struct nf_conntrack_man *, | |
61 | char); | |
62 | ||
63 | static struct ftp_search { | |
9fb9cbb1 YK |
64 | const char *pattern; |
65 | size_t plen; | |
66 | char skip; | |
67 | char term; | |
55a73324 | 68 | enum nf_ct_ftp_type ftptype; |
9fb9cbb1 | 69 | int (*getnum)(const char *, size_t, struct nf_conntrack_man *, char); |
7d8c5018 PM |
70 | } search[IP_CT_DIR_MAX][2] = { |
71 | [IP_CT_DIR_ORIGINAL] = { | |
72 | { | |
73 | .pattern = "PORT", | |
74 | .plen = sizeof("PORT") - 1, | |
75 | .skip = ' ', | |
76 | .term = '\r', | |
55a73324 | 77 | .ftptype = NF_CT_FTP_PORT, |
7d8c5018 PM |
78 | .getnum = try_rfc959, |
79 | }, | |
80 | { | |
81 | .pattern = "EPRT", | |
82 | .plen = sizeof("EPRT") - 1, | |
83 | .skip = ' ', | |
84 | .term = '\r', | |
55a73324 | 85 | .ftptype = NF_CT_FTP_EPRT, |
7d8c5018 PM |
86 | .getnum = try_eprt, |
87 | }, | |
9fb9cbb1 | 88 | }, |
7d8c5018 PM |
89 | [IP_CT_DIR_REPLY] = { |
90 | { | |
91 | .pattern = "227 ", | |
92 | .plen = sizeof("227 ") - 1, | |
93 | .skip = '(', | |
94 | .term = ')', | |
55a73324 | 95 | .ftptype = NF_CT_FTP_PASV, |
7d8c5018 PM |
96 | .getnum = try_rfc959, |
97 | }, | |
98 | { | |
99 | .pattern = "229 ", | |
100 | .plen = sizeof("229 ") - 1, | |
101 | .skip = '(', | |
102 | .term = ')', | |
55a73324 | 103 | .ftptype = NF_CT_FTP_EPSV, |
7d8c5018 PM |
104 | .getnum = try_epsv_response, |
105 | }, | |
9fb9cbb1 YK |
106 | }, |
107 | }; | |
108 | ||
9fb9cbb1 YK |
109 | static int |
110 | get_ipv6_addr(const char *src, size_t dlen, struct in6_addr *dst, u_int8_t term) | |
111 | { | |
6a28ec8c DM |
112 | const char *end; |
113 | int ret = in6_pton(src, min_t(size_t, dlen, 0xffff), (u8 *)dst, term, &end); | |
1884f78c YH |
114 | if (ret > 0) |
115 | return (int)(end - src); | |
116 | return 0; | |
9fb9cbb1 YK |
117 | } |
118 | ||
119 | static int try_number(const char *data, size_t dlen, u_int32_t array[], | |
601e68e1 | 120 | int array_size, char sep, char term) |
9fb9cbb1 YK |
121 | { |
122 | u_int32_t i, len; | |
123 | ||
124 | memset(array, 0, sizeof(array[0])*array_size); | |
125 | ||
126 | /* Keep data pointing at next char. */ | |
127 | for (i = 0, len = 0; len < dlen && i < array_size; len++, data++) { | |
128 | if (*data >= '0' && *data <= '9') { | |
129 | array[i] = array[i]*10 + *data - '0'; | |
130 | } | |
131 | else if (*data == sep) | |
132 | i++; | |
133 | else { | |
134 | /* Unexpected character; true if it's the | |
135 | terminator and we're finished. */ | |
136 | if (*data == term && i == array_size - 1) | |
137 | return len; | |
138 | ||
0d53778e PM |
139 | pr_debug("Char %u (got %u nums) `%u' unexpected\n", |
140 | len, i, *data); | |
9fb9cbb1 YK |
141 | return 0; |
142 | } | |
143 | } | |
0d53778e PM |
144 | pr_debug("Failed to fill %u numbers separated by %c\n", |
145 | array_size, sep); | |
9fb9cbb1 YK |
146 | return 0; |
147 | } | |
148 | ||
149 | /* Returns 0, or length of numbers: 192,168,1,1,5,6 */ | |
150 | static int try_rfc959(const char *data, size_t dlen, | |
151 | struct nf_conntrack_man *cmd, char term) | |
152 | { | |
153 | int length; | |
154 | u_int32_t array[6]; | |
155 | ||
156 | length = try_number(data, dlen, array, 6, ',', term); | |
157 | if (length == 0) | |
158 | return 0; | |
159 | ||
160 | cmd->u3.ip = htonl((array[0] << 24) | (array[1] << 16) | | |
161 | (array[2] << 8) | array[3]); | |
162 | cmd->u.tcp.port = htons((array[4] << 8) | array[5]); | |
163 | return length; | |
164 | } | |
165 | ||
166 | /* Grab port: number up to delimiter */ | |
167 | static int get_port(const char *data, int start, size_t dlen, char delim, | |
bff9a89b | 168 | __be16 *port) |
9fb9cbb1 YK |
169 | { |
170 | u_int16_t tmp_port = 0; | |
171 | int i; | |
172 | ||
173 | for (i = start; i < dlen; i++) { | |
174 | /* Finished? */ | |
175 | if (data[i] == delim) { | |
176 | if (tmp_port == 0) | |
177 | break; | |
178 | *port = htons(tmp_port); | |
0d53778e | 179 | pr_debug("get_port: return %d\n", tmp_port); |
9fb9cbb1 YK |
180 | return i + 1; |
181 | } | |
182 | else if (data[i] >= '0' && data[i] <= '9') | |
183 | tmp_port = tmp_port*10 + data[i] - '0'; | |
184 | else { /* Some other crap */ | |
0d53778e | 185 | pr_debug("get_port: invalid char.\n"); |
9fb9cbb1 YK |
186 | break; |
187 | } | |
188 | } | |
189 | return 0; | |
190 | } | |
191 | ||
192 | /* Returns 0, or length of numbers: |1|132.235.1.2|6275| or |2|3ffe::1|6275| */ | |
193 | static int try_eprt(const char *data, size_t dlen, struct nf_conntrack_man *cmd, | |
194 | char term) | |
195 | { | |
196 | char delim; | |
197 | int length; | |
198 | ||
199 | /* First character is delimiter, then "1" for IPv4 or "2" for IPv6, | |
200 | then delimiter again. */ | |
201 | if (dlen <= 3) { | |
0d53778e | 202 | pr_debug("EPRT: too short\n"); |
9fb9cbb1 YK |
203 | return 0; |
204 | } | |
205 | delim = data[0]; | |
206 | if (isdigit(delim) || delim < 33 || delim > 126 || data[2] != delim) { | |
0d53778e | 207 | pr_debug("try_eprt: invalid delimitter.\n"); |
9fb9cbb1 YK |
208 | return 0; |
209 | } | |
210 | ||
211 | if ((cmd->l3num == PF_INET && data[1] != '1') || | |
212 | (cmd->l3num == PF_INET6 && data[1] != '2')) { | |
0d53778e | 213 | pr_debug("EPRT: invalid protocol number.\n"); |
9fb9cbb1 YK |
214 | return 0; |
215 | } | |
216 | ||
0d53778e | 217 | pr_debug("EPRT: Got %c%c%c\n", delim, data[1], delim); |
9fb9cbb1 YK |
218 | |
219 | if (data[1] == '1') { | |
220 | u_int32_t array[4]; | |
221 | ||
222 | /* Now we have IP address. */ | |
223 | length = try_number(data + 3, dlen - 3, array, 4, '.', delim); | |
224 | if (length != 0) | |
225 | cmd->u3.ip = htonl((array[0] << 24) | (array[1] << 16) | |
226 | | (array[2] << 8) | array[3]); | |
227 | } else { | |
228 | /* Now we have IPv6 address. */ | |
229 | length = get_ipv6_addr(data + 3, dlen - 3, | |
230 | (struct in6_addr *)cmd->u3.ip6, delim); | |
231 | } | |
232 | ||
233 | if (length == 0) | |
234 | return 0; | |
0d53778e | 235 | pr_debug("EPRT: Got IP address!\n"); |
9fb9cbb1 YK |
236 | /* Start offset includes initial "|1|", and trailing delimiter */ |
237 | return get_port(data, 3 + length + 1, dlen, delim, &cmd->u.tcp.port); | |
238 | } | |
239 | ||
240 | /* Returns 0, or length of numbers: |||6446| */ | |
241 | static int try_epsv_response(const char *data, size_t dlen, | |
242 | struct nf_conntrack_man *cmd, char term) | |
243 | { | |
244 | char delim; | |
245 | ||
246 | /* Three delimiters. */ | |
247 | if (dlen <= 3) return 0; | |
248 | delim = data[0]; | |
f64f9e71 JP |
249 | if (isdigit(delim) || delim < 33 || delim > 126 || |
250 | data[1] != delim || data[2] != delim) | |
9fb9cbb1 YK |
251 | return 0; |
252 | ||
253 | return get_port(data, 3, dlen, delim, &cmd->u.tcp.port); | |
254 | } | |
255 | ||
256 | /* Return 1 for match, 0 for accept, -1 for partial. */ | |
257 | static int find_pattern(const char *data, size_t dlen, | |
258 | const char *pattern, size_t plen, | |
259 | char skip, char term, | |
260 | unsigned int *numoff, | |
261 | unsigned int *numlen, | |
262 | struct nf_conntrack_man *cmd, | |
263 | int (*getnum)(const char *, size_t, | |
264 | struct nf_conntrack_man *, char)) | |
265 | { | |
266 | size_t i; | |
267 | ||
0d53778e | 268 | pr_debug("find_pattern `%s': dlen = %Zu\n", pattern, dlen); |
9fb9cbb1 YK |
269 | if (dlen == 0) |
270 | return 0; | |
271 | ||
272 | if (dlen <= plen) { | |
273 | /* Short packet: try for partial? */ | |
274 | if (strnicmp(data, pattern, dlen) == 0) | |
275 | return -1; | |
276 | else return 0; | |
277 | } | |
278 | ||
279 | if (strnicmp(data, pattern, plen) != 0) { | |
280 | #if 0 | |
281 | size_t i; | |
282 | ||
0d53778e | 283 | pr_debug("ftp: string mismatch\n"); |
9fb9cbb1 | 284 | for (i = 0; i < plen; i++) { |
0d53778e PM |
285 | pr_debug("ftp:char %u `%c'(%u) vs `%c'(%u)\n", |
286 | i, data[i], data[i], | |
287 | pattern[i], pattern[i]); | |
9fb9cbb1 YK |
288 | } |
289 | #endif | |
290 | return 0; | |
291 | } | |
292 | ||
0d53778e | 293 | pr_debug("Pattern matches!\n"); |
9fb9cbb1 YK |
294 | /* Now we've found the constant string, try to skip |
295 | to the 'skip' character */ | |
296 | for (i = plen; data[i] != skip; i++) | |
297 | if (i == dlen - 1) return -1; | |
298 | ||
299 | /* Skip over the last character */ | |
300 | i++; | |
301 | ||
0d53778e | 302 | pr_debug("Skipped up to `%c'!\n", skip); |
9fb9cbb1 YK |
303 | |
304 | *numoff = i; | |
305 | *numlen = getnum(data + i, dlen - i, cmd, term); | |
306 | if (!*numlen) | |
307 | return -1; | |
308 | ||
0d53778e | 309 | pr_debug("Match succeeded!\n"); |
9fb9cbb1 YK |
310 | return 1; |
311 | } | |
312 | ||
313 | /* Look up to see if we're just after a \n. */ | |
55a73324 | 314 | static int find_nl_seq(u32 seq, const struct nf_ct_ftp_master *info, int dir) |
9fb9cbb1 YK |
315 | { |
316 | unsigned int i; | |
317 | ||
318 | for (i = 0; i < info->seq_aft_nl_num[dir]; i++) | |
319 | if (info->seq_aft_nl[dir][i] == seq) | |
320 | return 1; | |
321 | return 0; | |
322 | } | |
323 | ||
324 | /* We don't update if it's older than what we have. */ | |
a71996fc AD |
325 | static void update_nl_seq(struct nf_conn *ct, u32 nl_seq, |
326 | struct nf_ct_ftp_master *info, int dir, | |
9fb9cbb1 YK |
327 | struct sk_buff *skb) |
328 | { | |
aaff23a9 | 329 | unsigned int i, oldest; |
9fb9cbb1 YK |
330 | |
331 | /* Look for oldest: if we find exact match, we're done. */ | |
332 | for (i = 0; i < info->seq_aft_nl_num[dir]; i++) { | |
333 | if (info->seq_aft_nl[dir][i] == nl_seq) | |
334 | return; | |
9fb9cbb1 YK |
335 | } |
336 | ||
337 | if (info->seq_aft_nl_num[dir] < NUM_SEQ_TO_REMEMBER) { | |
338 | info->seq_aft_nl[dir][info->seq_aft_nl_num[dir]++] = nl_seq; | |
aaff23a9 PM |
339 | } else { |
340 | if (before(info->seq_aft_nl[dir][0], info->seq_aft_nl[dir][1])) | |
341 | oldest = 0; | |
342 | else | |
343 | oldest = 1; | |
344 | ||
345 | if (after(nl_seq, info->seq_aft_nl[dir][oldest])) | |
346 | info->seq_aft_nl[dir][oldest] = nl_seq; | |
9fb9cbb1 YK |
347 | } |
348 | } | |
349 | ||
3db05fea | 350 | static int help(struct sk_buff *skb, |
9fb9cbb1 YK |
351 | unsigned int protoff, |
352 | struct nf_conn *ct, | |
353 | enum ip_conntrack_info ctinfo) | |
354 | { | |
355 | unsigned int dataoff, datalen; | |
58c0fb0d JE |
356 | const struct tcphdr *th; |
357 | struct tcphdr _tcph; | |
358 | const char *fb_ptr; | |
9fb9cbb1 YK |
359 | int ret; |
360 | u32 seq; | |
361 | int dir = CTINFO2DIR(ctinfo); | |
d6e8cc6c | 362 | unsigned int uninitialized_var(matchlen), uninitialized_var(matchoff); |
1afc5679 | 363 | struct nf_ct_ftp_master *ct_ftp_info = nfct_help_data(ct); |
9fb9cbb1 | 364 | struct nf_conntrack_expect *exp; |
643a2c15 | 365 | union nf_inet_addr *daddr; |
9fb9cbb1 | 366 | struct nf_conntrack_man cmd = {}; |
9fb9cbb1 YK |
367 | unsigned int i; |
368 | int found = 0, ends_in_nl; | |
337fbc41 | 369 | typeof(nf_nat_ftp_hook) nf_nat_ftp; |
9fb9cbb1 YK |
370 | |
371 | /* Until there's been traffic both ways, don't look in packets. */ | |
f64f9e71 | 372 | if (ctinfo != IP_CT_ESTABLISHED && |
fb048833 | 373 | ctinfo != IP_CT_ESTABLISHED_REPLY) { |
0d53778e | 374 | pr_debug("ftp: Conntrackinfo = %u\n", ctinfo); |
9fb9cbb1 YK |
375 | return NF_ACCEPT; |
376 | } | |
377 | ||
3db05fea | 378 | th = skb_header_pointer(skb, protoff, sizeof(_tcph), &_tcph); |
9fb9cbb1 YK |
379 | if (th == NULL) |
380 | return NF_ACCEPT; | |
381 | ||
382 | dataoff = protoff + th->doff * 4; | |
383 | /* No data? */ | |
3db05fea | 384 | if (dataoff >= skb->len) { |
0d53778e | 385 | pr_debug("ftp: dataoff(%u) >= skblen(%u)\n", dataoff, |
3db05fea | 386 | skb->len); |
9fb9cbb1 YK |
387 | return NF_ACCEPT; |
388 | } | |
3db05fea | 389 | datalen = skb->len - dataoff; |
9fb9cbb1 YK |
390 | |
391 | spin_lock_bh(&nf_ftp_lock); | |
3db05fea | 392 | fb_ptr = skb_header_pointer(skb, dataoff, datalen, ftp_buffer); |
9fb9cbb1 YK |
393 | BUG_ON(fb_ptr == NULL); |
394 | ||
395 | ends_in_nl = (fb_ptr[datalen - 1] == '\n'); | |
396 | seq = ntohl(th->seq) + datalen; | |
397 | ||
398 | /* Look up to see if we're just after a \n. */ | |
399 | if (!find_nl_seq(ntohl(th->seq), ct_ftp_info, dir)) { | |
7be54ca4 PNA |
400 | /* We're picking up this, clear flags and let it continue */ |
401 | if (unlikely(ct_ftp_info->flags[dir] & NF_CT_FTP_SEQ_PICKUP)) { | |
402 | ct_ftp_info->flags[dir] ^= NF_CT_FTP_SEQ_PICKUP; | |
403 | goto skip_nl_seq; | |
404 | } | |
405 | ||
9fb9cbb1 | 406 | /* Now if this ends in \n, update ftp info. */ |
0d53778e PM |
407 | pr_debug("nf_conntrack_ftp: wrong seq pos %s(%u) or %s(%u)\n", |
408 | ct_ftp_info->seq_aft_nl_num[dir] > 0 ? "" : "(UNSET)", | |
409 | ct_ftp_info->seq_aft_nl[dir][0], | |
410 | ct_ftp_info->seq_aft_nl_num[dir] > 1 ? "" : "(UNSET)", | |
411 | ct_ftp_info->seq_aft_nl[dir][1]); | |
9fb9cbb1 YK |
412 | ret = NF_ACCEPT; |
413 | goto out_update_nl; | |
414 | } | |
415 | ||
7be54ca4 | 416 | skip_nl_seq: |
601e68e1 YH |
417 | /* Initialize IP/IPv6 addr to expected address (it's not mentioned |
418 | in EPSV responses) */ | |
5e8fbe2a | 419 | cmd.l3num = nf_ct_l3num(ct); |
9fb9cbb1 YK |
420 | memcpy(cmd.u3.all, &ct->tuplehash[dir].tuple.src.u3.all, |
421 | sizeof(cmd.u3.all)); | |
422 | ||
7d8c5018 | 423 | for (i = 0; i < ARRAY_SIZE(search[dir]); i++) { |
9fb9cbb1 | 424 | found = find_pattern(fb_ptr, datalen, |
7d8c5018 PM |
425 | search[dir][i].pattern, |
426 | search[dir][i].plen, | |
427 | search[dir][i].skip, | |
428 | search[dir][i].term, | |
9fb9cbb1 YK |
429 | &matchoff, &matchlen, |
430 | &cmd, | |
7d8c5018 | 431 | search[dir][i].getnum); |
9fb9cbb1 YK |
432 | if (found) break; |
433 | } | |
434 | if (found == -1) { | |
435 | /* We don't usually drop packets. After all, this is | |
436 | connection tracking, not packet filtering. | |
437 | However, it is necessary for accurate tracking in | |
438 | this case. */ | |
b20ab9cc PNA |
439 | nf_ct_helper_log(skb, ct, "partial matching of `%s'", |
440 | search[dir][i].pattern); | |
9fb9cbb1 YK |
441 | ret = NF_DROP; |
442 | goto out; | |
443 | } else if (found == 0) { /* No match */ | |
444 | ret = NF_ACCEPT; | |
445 | goto out_update_nl; | |
446 | } | |
447 | ||
0d53778e PM |
448 | pr_debug("conntrack_ftp: match `%.*s' (%u bytes at %u)\n", |
449 | matchlen, fb_ptr + matchoff, | |
450 | matchlen, ntohl(th->seq) + matchoff); | |
9fb9cbb1 | 451 | |
6823645d | 452 | exp = nf_ct_expect_alloc(ct); |
9fb9cbb1 | 453 | if (exp == NULL) { |
b20ab9cc | 454 | nf_ct_helper_log(skb, ct, "cannot alloc expectation"); |
9fb9cbb1 YK |
455 | ret = NF_DROP; |
456 | goto out; | |
457 | } | |
458 | ||
459 | /* We refer to the reverse direction ("!dir") tuples here, | |
460 | * because we're expecting something in the other direction. | |
461 | * Doesn't matter unless NAT is happening. */ | |
df43b4e7 | 462 | daddr = &ct->tuplehash[!dir].tuple.dst.u3; |
9fb9cbb1 YK |
463 | |
464 | /* Update the ftp info */ | |
5e8fbe2a | 465 | if ((cmd.l3num == nf_ct_l3num(ct)) && |
9fb9cbb1 YK |
466 | memcmp(&cmd.u3.all, &ct->tuplehash[dir].tuple.src.u3.all, |
467 | sizeof(cmd.u3.all))) { | |
468 | /* Enrico Scholz's passive FTP to partially RNAT'd ftp | |
601e68e1 YH |
469 | server: it really wants us to connect to a |
470 | different IP address. Simply don't record it for | |
471 | NAT. */ | |
9fb9cbb1 | 472 | if (cmd.l3num == PF_INET) { |
14d5e834 HH |
473 | pr_debug("conntrack_ftp: NOT RECORDING: %pI4 != %pI4\n", |
474 | &cmd.u3.ip, | |
475 | &ct->tuplehash[dir].tuple.src.u3.ip); | |
9fb9cbb1 | 476 | } else { |
5b095d98 | 477 | pr_debug("conntrack_ftp: NOT RECORDING: %pI6 != %pI6\n", |
38ff4fa4 HH |
478 | cmd.u3.ip6, |
479 | ct->tuplehash[dir].tuple.src.u3.ip6); | |
9fb9cbb1 YK |
480 | } |
481 | ||
482 | /* Thanks to Cristiano Lincoln Mattos | |
483 | <lincoln@cesar.org.br> for reporting this potential | |
484 | problem (DMZ machines opening holes to internal | |
485 | networks, or the packet filter itself). */ | |
486 | if (!loose) { | |
487 | ret = NF_ACCEPT; | |
488 | goto out_put_expect; | |
489 | } | |
df43b4e7 | 490 | daddr = &cmd.u3; |
9fb9cbb1 YK |
491 | } |
492 | ||
6002f266 | 493 | nf_ct_expect_init(exp, NF_CT_EXPECT_CLASS_DEFAULT, cmd.l3num, |
df43b4e7 PM |
494 | &ct->tuplehash[!dir].tuple.src.u3, daddr, |
495 | IPPROTO_TCP, NULL, &cmd.u.tcp.port); | |
9fb9cbb1 YK |
496 | |
497 | /* Now, NAT might want to mangle the packet, and register the | |
498 | * (possibly changed) expectation itself. */ | |
337fbc41 | 499 | nf_nat_ftp = rcu_dereference(nf_nat_ftp_hook); |
d33cbeeb | 500 | if (nf_nat_ftp && ct->status & IPS_NAT_MASK) |
3db05fea | 501 | ret = nf_nat_ftp(skb, ctinfo, search[dir][i].ftptype, |
051966c0 | 502 | protoff, matchoff, matchlen, exp); |
9fb9cbb1 YK |
503 | else { |
504 | /* Can't expect this? Best to drop packet now. */ | |
b20ab9cc PNA |
505 | if (nf_ct_expect_related(exp) != 0) { |
506 | nf_ct_helper_log(skb, ct, "cannot add expectation"); | |
9fb9cbb1 | 507 | ret = NF_DROP; |
b20ab9cc | 508 | } else |
9fb9cbb1 YK |
509 | ret = NF_ACCEPT; |
510 | } | |
511 | ||
512 | out_put_expect: | |
6823645d | 513 | nf_ct_expect_put(exp); |
9fb9cbb1 YK |
514 | |
515 | out_update_nl: | |
516 | /* Now if this ends in \n, update ftp info. Seq may have been | |
517 | * adjusted by NAT code. */ | |
518 | if (ends_in_nl) | |
a71996fc | 519 | update_nl_seq(ct, seq, ct_ftp_info, dir, skb); |
9fb9cbb1 YK |
520 | out: |
521 | spin_unlock_bh(&nf_ftp_lock); | |
522 | return ret; | |
523 | } | |
524 | ||
7be54ca4 PNA |
525 | static int nf_ct_ftp_from_nlattr(struct nlattr *attr, struct nf_conn *ct) |
526 | { | |
527 | struct nf_ct_ftp_master *ftp = nfct_help_data(ct); | |
528 | ||
529 | /* This conntrack has been injected from user-space, always pick up | |
530 | * sequence tracking. Otherwise, the first FTP command after the | |
531 | * failover breaks. | |
532 | */ | |
533 | ftp->flags[IP_CT_DIR_ORIGINAL] |= NF_CT_FTP_SEQ_PICKUP; | |
534 | ftp->flags[IP_CT_DIR_REPLY] |= NF_CT_FTP_SEQ_PICKUP; | |
535 | return 0; | |
536 | } | |
537 | ||
ec59a111 | 538 | static struct nf_conntrack_helper ftp[MAX_PORTS][2] __read_mostly; |
9fb9cbb1 | 539 | |
6002f266 PM |
540 | static const struct nf_conntrack_expect_policy ftp_exp_policy = { |
541 | .max_expected = 1, | |
542 | .timeout = 5 * 60, | |
543 | }; | |
544 | ||
9fb9cbb1 | 545 | /* don't make this __exit, since it's called from __init ! */ |
65b4b4e8 | 546 | static void nf_conntrack_ftp_fini(void) |
9fb9cbb1 YK |
547 | { |
548 | int i, j; | |
549 | for (i = 0; i < ports_c; i++) { | |
550 | for (j = 0; j < 2; j++) { | |
551 | if (ftp[i][j].me == NULL) | |
552 | continue; | |
553 | ||
0d53778e PM |
554 | pr_debug("nf_ct_ftp: unregistering helper for pf: %d " |
555 | "port: %d\n", | |
556 | ftp[i][j].tuple.src.l3num, ports[i]); | |
9fb9cbb1 YK |
557 | nf_conntrack_helper_unregister(&ftp[i][j]); |
558 | } | |
559 | } | |
560 | ||
561 | kfree(ftp_buffer); | |
562 | } | |
563 | ||
65b4b4e8 | 564 | static int __init nf_conntrack_ftp_init(void) |
9fb9cbb1 YK |
565 | { |
566 | int i, j = -1, ret = 0; | |
9fb9cbb1 YK |
567 | |
568 | ftp_buffer = kmalloc(65536, GFP_KERNEL); | |
569 | if (!ftp_buffer) | |
570 | return -ENOMEM; | |
571 | ||
572 | if (ports_c == 0) | |
573 | ports[ports_c++] = FTP_PORT; | |
574 | ||
575 | /* FIXME should be configurable whether IPv4 and IPv6 FTP connections | |
576 | are tracked or not - YK */ | |
577 | for (i = 0; i < ports_c; i++) { | |
9fb9cbb1 YK |
578 | ftp[i][0].tuple.src.l3num = PF_INET; |
579 | ftp[i][1].tuple.src.l3num = PF_INET6; | |
580 | for (j = 0; j < 2; j++) { | |
1afc5679 | 581 | ftp[i][j].data_len = sizeof(struct nf_ct_ftp_master); |
9fb9cbb1 YK |
582 | ftp[i][j].tuple.src.u.tcp.port = htons(ports[i]); |
583 | ftp[i][j].tuple.dst.protonum = IPPROTO_TCP; | |
6002f266 | 584 | ftp[i][j].expect_policy = &ftp_exp_policy; |
9fb9cbb1 YK |
585 | ftp[i][j].me = THIS_MODULE; |
586 | ftp[i][j].help = help; | |
7be54ca4 | 587 | ftp[i][j].from_nlattr = nf_ct_ftp_from_nlattr; |
9fb9cbb1 | 588 | if (ports[i] == FTP_PORT) |
3a8fc53a | 589 | sprintf(ftp[i][j].name, "ftp"); |
9fb9cbb1 | 590 | else |
3a8fc53a | 591 | sprintf(ftp[i][j].name, "ftp-%d", ports[i]); |
9fb9cbb1 | 592 | |
0d53778e PM |
593 | pr_debug("nf_ct_ftp: registering helper for pf: %d " |
594 | "port: %d\n", | |
595 | ftp[i][j].tuple.src.l3num, ports[i]); | |
9fb9cbb1 YK |
596 | ret = nf_conntrack_helper_register(&ftp[i][j]); |
597 | if (ret) { | |
654d0fbd SH |
598 | printk(KERN_ERR "nf_ct_ftp: failed to register" |
599 | " helper for pf: %d port: %d\n", | |
9fb9cbb1 | 600 | ftp[i][j].tuple.src.l3num, ports[i]); |
65b4b4e8 | 601 | nf_conntrack_ftp_fini(); |
9fb9cbb1 YK |
602 | return ret; |
603 | } | |
604 | } | |
605 | } | |
606 | ||
607 | return 0; | |
608 | } | |
609 | ||
65b4b4e8 AM |
610 | module_init(nf_conntrack_ftp_init); |
611 | module_exit(nf_conntrack_ftp_fini); |