1
2 /*
3 * Copyright (C) Igor Sysoev
4 */
5
6
7 #include <ngx_config.h>
8 #include <ngx_core.h>
9 #include <ngx_event.h>
10 #include <ngx_mail.h>
11 #include <ngx_mail_smtp_module.h>
12
13
14 static void ngx_mail_smtp_invalid_pipelining(ngx_event_t *rev);
15 static ngx_int_t ngx_mail_smtp_create_buffer(ngx_mail_session_t *s,
16 ngx_connection_t *c);
17
18 static ngx_int_t ngx_mail_smtp_helo(ngx_mail_session_t *s, ngx_connection_t *c);
19 static ngx_int_t ngx_mail_smtp_auth(ngx_mail_session_t *s, ngx_connection_t *c);
20 static ngx_int_t ngx_mail_smtp_mail(ngx_mail_session_t *s, ngx_connection_t *c);
21 static ngx_int_t ngx_mail_smtp_starttls(ngx_mail_session_t *s,
22 ngx_connection_t *c);
23
24 static ngx_int_t ngx_mail_smtp_discard_command(ngx_mail_session_t *s,
25 ngx_connection_t *c, char *err);
26 static void ngx_mail_smtp_log_rejected_command(ngx_mail_session_t *s,
27 ngx_connection_t *c, char *err);
28
29
30 static u_char smtp_ok[] = "250 2.0.0 OK" CRLF;
31 static u_char smtp_bye[] = "221 2.0.0 Bye" CRLF;
32 static u_char smtp_starttls[] = "220 2.0.0 Start TLS" CRLF;
33 static u_char smtp_next[] = "334 " CRLF;
34 static u_char smtp_username[] = "334 VXNlcm5hbWU6" CRLF;
35 static u_char smtp_password[] = "334 UGFzc3dvcmQ6" CRLF;
36 static u_char smtp_invalid_command[] = "500 5.5.1 Invalid command" CRLF;
37 static u_char smtp_invalid_pipelining[] =
38 "503 5.5.0 Improper use of SMTP command pipelining" CRLF;
39 static u_char smtp_invalid_argument[] = "501 5.5.4 Invalid argument" CRLF;
40 static u_char smtp_auth_required[] = "530 5.7.1 Authentication required" CRLF;
41
42
43 void
44 ngx_mail_smtp_init_session(ngx_mail_session_t *s, ngx_connection_t *c)
45 {
46 ngx_msec_t timeout;
47 ngx_mail_core_srv_conf_t *cscf;
48 ngx_mail_smtp_srv_conf_t *sscf;
49
50 cscf = ngx_mail_get_module_srv_conf(s, ngx_mail_core_module);
51 sscf = ngx_mail_get_module_srv_conf(s, ngx_mail_smtp_module);
52
53 timeout = sscf->greeting_delay ? sscf->greeting_delay : cscf->timeout;
54 ngx_add_timer(c->read, timeout);
55
56 if (ngx_handle_read_event(c->read, 0) == NGX_ERROR) {
57 ngx_mail_close_connection(c);
58 }
59
60 if (sscf->greeting_delay) {
61 c->read->handler = ngx_mail_smtp_invalid_pipelining;
62 return;
63 }
64
65 c->read->handler = ngx_mail_smtp_init_protocol;
66
67 s->out = sscf->greeting;
68
69 ngx_mail_send(c->write);
70 }
71
72
73 static void
74 ngx_mail_smtp_invalid_pipelining(ngx_event_t *rev)
75 {
76 ngx_connection_t *c;
77 ngx_mail_session_t *s;
78 ngx_mail_core_srv_conf_t *cscf;
79 ngx_mail_smtp_srv_conf_t *sscf;
80
81 c = rev->data;
82 s = c->data;
83
84 c->log->action = "in delay pipelining state";
85
86 if (rev->timedout) {
87
88 ngx_log_debug0(NGX_LOG_DEBUG_MAIL, c->log, 0, "delay greeting");
89
90 rev->timedout = 0;
91
92 cscf = ngx_mail_get_module_srv_conf(s, ngx_mail_core_module);
93
94 c->read->handler = ngx_mail_smtp_init_protocol;
95
96 ngx_add_timer(c->read, cscf->timeout);
97
98 if (ngx_handle_read_event(c->read, 0) == NGX_ERROR) {
99 ngx_mail_close_connection(c);
100 return;
101 }
102
103 sscf = ngx_mail_get_module_srv_conf(s, ngx_mail_smtp_module);
104
105 s->out = sscf->greeting;
106
107 } else {
108
109 ngx_log_debug0(NGX_LOG_DEBUG_MAIL, c->log, 0, "invalid pipelining");
110
111 if (s->buffer == NULL) {
112 if (ngx_mail_smtp_create_buffer(s, c) != NGX_OK) {
113 return;
114 }
115 }
116
117 if (ngx_mail_smtp_discard_command(s, c,
118 "client was rejected before greeting: \"%V\"")
119 != NGX_OK)
120 {
121 return;
122 }
123
124 s->out.len = sizeof(smtp_invalid_pipelining) - 1;
125 s->out.data = smtp_invalid_pipelining;
126 }
127
128 ngx_mail_send(c->write);
129 }
130
131
132 void
133 ngx_mail_smtp_init_protocol(ngx_event_t *rev)
134 {
135 ngx_connection_t *c;
136 ngx_mail_session_t *s;
137
138 c = rev->data;
139
140 c->log->action = "in auth state";
141
142 if (rev->timedout) {
143 ngx_log_error(NGX_LOG_INFO, c->log, NGX_ETIMEDOUT, "client timed out");
144 c->timedout = 1;
145 ngx_mail_close_connection(c);
146 return;
147 }
148
149 s = c->data;
150
151 if (s->buffer == NULL) {
152 if (ngx_mail_smtp_create_buffer(s, c) != NGX_OK) {
153 return;
154 }
155 }
156
157 s->mail_state = ngx_smtp_start;
158 c->read->handler = ngx_mail_smtp_auth_state;
159
160 ngx_mail_smtp_auth_state(rev);
161 }
162
163
164 static ngx_int_t
165 ngx_mail_smtp_create_buffer(ngx_mail_session_t *s, ngx_connection_t *c)
166 {
167 ngx_mail_smtp_srv_conf_t *sscf;
168
169 if (ngx_array_init(&s->args, c->pool, 2, sizeof(ngx_str_t)) == NGX_ERROR) {
170 ngx_mail_session_internal_server_error(s);
171 return NGX_ERROR;
172 }
173
174 sscf = ngx_mail_get_module_srv_conf(s, ngx_mail_smtp_module);
175
176 s->buffer = ngx_create_temp_buf(c->pool, sscf->client_buffer_size);
177 if (s->buffer == NULL) {
178 ngx_mail_session_internal_server_error(s);
179 return NGX_ERROR;
180 }
181
182 return NGX_OK;
183 }
184
185
186 void
187 ngx_mail_smtp_auth_state(ngx_event_t *rev)
188 {
189 ngx_int_t rc;
190 ngx_connection_t *c;
191 ngx_mail_session_t *s;
192
193 c = rev->data;
194 s = c->data;
195
196 ngx_log_debug0(NGX_LOG_DEBUG_MAIL, c->log, 0, "smtp auth state");
197
198 if (rev->timedout) {
199 ngx_log_error(NGX_LOG_INFO, c->log, NGX_ETIMEDOUT, "client timed out");
200 c->timedout = 1;
201 ngx_mail_close_connection(c);
202 return;
203 }
204
205 if (s->out.len) {
206 ngx_log_debug0(NGX_LOG_DEBUG_MAIL, c->log, 0, "smtp send handler busy");
207 s->blocked = 1;
208 return;
209 }
210
211 s->blocked = 0;
212
213 rc = ngx_mail_read_command(s, c);
214
215 if (rc == NGX_AGAIN || rc == NGX_ERROR) {
216 return;
217 }
218
219 s->out.len = sizeof(smtp_ok) - 1;
220 s->out.data = smtp_ok;
221
222 if (rc == NGX_OK) {
223 switch (s->mail_state) {
224
225 case ngx_smtp_start:
226
227 switch (s->command) {
228
229 case NGX_SMTP_HELO:
230 case NGX_SMTP_EHLO:
231 rc = ngx_mail_smtp_helo(s, c);
232 break;
233
234 case NGX_SMTP_AUTH:
235 rc = ngx_mail_smtp_auth(s, c);
236 break;
237
238 case NGX_SMTP_QUIT:
239 s->quit = 1;
240 s->out.len = sizeof(smtp_bye) - 1;
241 s->out.data = smtp_bye;
242 break;
243
244 case NGX_SMTP_MAIL:
245 rc = ngx_mail_smtp_mail(s, c);
246 break;
247
248 case NGX_SMTP_NOOP:
249 case NGX_SMTP_RSET:
250 break;
251
252 case NGX_SMTP_STARTTLS:
253 rc = ngx_mail_smtp_starttls(s, c);
254 s->out.len = sizeof(smtp_starttls) - 1;
255 s->out.data = smtp_starttls;
256 break;
257
258 default:
259 rc = NGX_MAIL_PARSE_INVALID_COMMAND;
260 break;
261 }
262
263 break;
264
265 case ngx_smtp_auth_login_username:
266 rc = ngx_mail_auth_login_username(s, c);
267
268 s->out.len = sizeof(smtp_password) - 1;
269 s->out.data = smtp_password;
270 s->mail_state = ngx_smtp_auth_login_password;
271 break;
272
273 case ngx_smtp_auth_login_password:
274 rc = ngx_mail_auth_login_password(s, c);
275 break;
276
277 case ngx_smtp_auth_plain:
278 rc = ngx_mail_auth_plain(s, c, 0);
279 break;
280
281 case ngx_smtp_auth_cram_md5:
282 rc = ngx_mail_auth_cram_md5(s, c);
283 break;
284 }
285 }
286
287 switch (rc) {
288
289 case NGX_DONE:
290 ngx_mail_auth(s, c);
291 return;
292
293 case NGX_ERROR:
294 ngx_mail_session_internal_server_error(s);
295 return;
296
297 case NGX_MAIL_PARSE_INVALID_COMMAND:
298 s->mail_state = ngx_smtp_start;
299 s->state = 0;
300
301 s->out.len = sizeof(smtp_invalid_command) - 1;
302 s->out.data = smtp_invalid_command;
303
304 /* fall through */
305
306 case NGX_OK:
307 s->args.nelts = 0;
308 s->buffer->pos = s->buffer->start;
309 s->buffer->last = s->buffer->start;
310
311 if (s->state) {
312 s->arg_start = s->buffer->start;
313 }
314
315 ngx_mail_send(c->write);
316 }
317 }
318
319
320 static ngx_int_t
321 ngx_mail_smtp_helo(ngx_mail_session_t *s, ngx_connection_t *c)
322 {
323 ngx_str_t *arg;
324 ngx_mail_smtp_srv_conf_t *sscf;
325
326 if (s->args.nelts != 1) {
327 s->out.len = sizeof(smtp_invalid_argument) - 1;
328 s->out.data = smtp_invalid_argument;
329 s->state = 0;
330 return NGX_OK;
331 }
332
333 arg = s->args.elts;
334
335 s->smtp_helo.len = arg[0].len;
336
337 s->smtp_helo.data = ngx_palloc(c->pool, arg[0].len);
338 if (s->smtp_helo.data == NULL) {
339 return NGX_ERROR;
340 }
341
342 ngx_memcpy(s->smtp_helo.data, arg[0].data, arg[0].len);
343
344 sscf = ngx_mail_get_module_srv_conf(s, ngx_mail_smtp_module);
345
346 if (s->command == NGX_SMTP_HELO) {
347 s->out = sscf->server_name;
348
349 } else {
350 s->esmtp = 1;
351
352 #if (NGX_MAIL_SSL)
353
354 if (c->ssl == NULL) {
355 ngx_mail_ssl_conf_t *sslcf;
356
357 sslcf = ngx_mail_get_module_srv_conf(s, ngx_mail_ssl_module);
358
359 if (sslcf->starttls == NGX_MAIL_STARTTLS_ON) {
360 s->out = sscf->starttls_capability;
361 return NGX_OK;
362 }
363
364 if (sslcf->starttls == NGX_MAIL_STARTTLS_ONLY) {
365 s->out = sscf->starttls_only_capability;
366 return NGX_OK;
367 }
368 }
369 #endif
370
371 s->out = sscf->capability;
372 }
373
374 return NGX_OK;
375 }
376
377
378 static ngx_int_t
379 ngx_mail_smtp_auth(ngx_mail_session_t *s, ngx_connection_t *c)
380 {
381 ngx_int_t rc;
382 ngx_mail_core_srv_conf_t *cscf;
383 ngx_mail_smtp_srv_conf_t *sscf;
384
385 #if (NGX_MAIL_SSL)
386 if (ngx_mail_starttls_only(s, c)) {
387 return NGX_MAIL_PARSE_INVALID_COMMAND;
388 }
389 #endif
390
391 if (s->args.nelts == 0) {
392 s->out.len = sizeof(smtp_invalid_argument) - 1;
393 s->out.data = smtp_invalid_argument;
394 s->state = 0;
395 return NGX_OK;
396 }
397
398 rc = ngx_mail_auth_parse(s, c);
399
400 switch (rc) {
401
402 case NGX_MAIL_AUTH_LOGIN:
403
404 s->out.len = sizeof(smtp_username) - 1;
405 s->out.data = smtp_username;
406 s->mail_state = ngx_smtp_auth_login_username;
407
408 return NGX_OK;
409
410 case NGX_MAIL_AUTH_PLAIN:
411
412 s->out.len = sizeof(smtp_next) - 1;
413 s->out.data = smtp_next;
414 s->mail_state = ngx_smtp_auth_plain;
415
416 return NGX_OK;
417
418 case NGX_MAIL_AUTH_CRAM_MD5:
419
420 sscf = ngx_mail_get_module_srv_conf(s, ngx_mail_smtp_module);
421
422 if (!(sscf->auth_methods & NGX_MAIL_AUTH_CRAM_MD5_ENABLED)) {
423 return NGX_MAIL_PARSE_INVALID_COMMAND;
424 }
425
426 if (s->salt.data == NULL) {
427 cscf = ngx_mail_get_module_srv_conf(s, ngx_mail_core_module);
428
429 if (ngx_mail_salt(s, c, cscf) != NGX_OK) {
430 return NGX_ERROR;
431 }
432 }
433
434 if (ngx_mail_auth_cram_md5_salt(s, c, "334 ", 4) == NGX_OK) {
435 s->mail_state = ngx_smtp_auth_cram_md5;
436 return NGX_OK;
437 }
438
439 return NGX_ERROR;
440 }
441
442 return rc;
443 }
444
445
446 static ngx_int_t
447 ngx_mail_smtp_mail(ngx_mail_session_t *s, ngx_connection_t *c)
448 {
449 ngx_mail_smtp_log_rejected_command(s, c, "client was rejected: \"%V\"");
450
451 s->out.len = sizeof(smtp_auth_required) - 1;
452 s->out.data = smtp_auth_required;
453
454 return NGX_OK;
455 }
456
457
458 static ngx_int_t
459 ngx_mail_smtp_starttls(ngx_mail_session_t *s, ngx_connection_t *c)
460 {
461 #if (NGX_MAIL_SSL)
462 ngx_mail_ssl_conf_t *sslcf;
463
464 if (c->ssl == NULL) {
465 sslcf = ngx_mail_get_module_srv_conf(s, ngx_mail_ssl_module);
466 if (sslcf->starttls) {
467
468 /*
469 * RFC3207 requires us to discard any knowledge
470 * obtained from client before STARTTLS.
471 */
472
473 s->smtp_helo.len = 0;
474 s->smtp_helo.data = NULL;
475
476 c->read->handler = ngx_mail_starttls_handler;
477 return NGX_OK;
478 }
479 }
480
481 #endif
482
483 return NGX_MAIL_PARSE_INVALID_COMMAND;
484 }
485
486
487 static ngx_int_t
488 ngx_mail_smtp_discard_command(ngx_mail_session_t *s, ngx_connection_t *c,
489 char *err)
490 {
491 ssize_t n;
492
493 n = c->recv(c, s->buffer->last, s->buffer->end - s->buffer->last);
494
495 if (n == NGX_ERROR || n == 0) {
496 ngx_mail_close_connection(c);
497 return NGX_ERROR;
498 }
499
500 if (n > 0) {
501 s->buffer->last += n;
502 }
503
504 if (n == NGX_AGAIN) {
505 if (ngx_handle_read_event(c->read, 0) == NGX_ERROR) {
506 ngx_mail_session_internal_server_error(s);
507 return NGX_ERROR;
508 }
509
510 return NGX_AGAIN;
511 }
512
513 ngx_mail_smtp_log_rejected_command(s, c, err);
514
515 s->buffer->pos = s->buffer->start;
516 s->buffer->last = s->buffer->start;
517
518 return NGX_OK;
519 }
520
521
522 static void
523 ngx_mail_smtp_log_rejected_command(ngx_mail_session_t *s, ngx_connection_t *c,
524 char *err)
525 {
526 u_char ch;
527 ngx_str_t cmd;
528 ngx_uint_t i;
529
530 if (c->log->log_level < NGX_LOG_INFO) {
531 return;
532 }
533
534 cmd.len = s->buffer->last - s->buffer->start;
535 cmd.data = s->buffer->start;
536
537 for (i = 0; i < cmd.len; i++) {
538 ch = cmd.data[i];
539
540 if (ch != CR && ch != LF) {
541 continue;
542 }
543
544 cmd.data[i] = '_';
545 }
546
547 cmd.len = i;
548
549 ngx_log_error(NGX_LOG_INFO, c->log, 0, err, &cmd);
550 }
551
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