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981756db | 1 | /* $Cambridge: exim/src/src/smtp_in.c,v 1.5 2004/11/10 15:21:16 ph10 Exp $ */ |
059ec3d9 PH |
2 | |
3 | /************************************************* | |
4 | * Exim - an Internet mail transport agent * | |
5 | *************************************************/ | |
6 | ||
7 | /* Copyright (c) University of Cambridge 1995 - 2004 */ | |
8 | /* See the file NOTICE for conditions of use and distribution. */ | |
9 | ||
10 | /* Functions for handling an incoming SMTP call. */ | |
11 | ||
12 | ||
13 | #include "exim.h" | |
14 | ||
15 | ||
16 | /* Initialize for TCP wrappers if so configured. It appears that the macro | |
17 | HAVE_IPV6 is used in some versions of the tcpd.h header, so we unset it before | |
18 | including that header, and restore its value afterwards. */ | |
19 | ||
20 | #ifdef USE_TCP_WRAPPERS | |
21 | ||
22 | #if HAVE_IPV6 | |
23 | #define EXIM_HAVE_IPV6 | |
24 | #endif | |
25 | #undef HAVE_IPV6 | |
26 | #include <tcpd.h> | |
27 | #undef HAVE_IPV6 | |
28 | #ifdef EXIM_HAVE_IPV6 | |
29 | #define HAVE_IPV6 TRUE | |
30 | #endif | |
31 | ||
32 | int allow_severity = LOG_INFO; | |
33 | int deny_severity = LOG_NOTICE; | |
34 | #endif | |
35 | ||
36 | ||
37 | /* Size of buffer for reading SMTP commands */ | |
38 | ||
39 | #define cmd_buffer_size 512 /* Ref. RFC 821 */ | |
40 | ||
41 | /* Size of buffer for reading SMTP incoming packets */ | |
42 | ||
43 | #define in_buffer_size 8192 | |
44 | ||
45 | /* Structure for SMTP command list */ | |
46 | ||
47 | typedef struct { | |
48 | char *name; | |
49 | int len; | |
50 | short int cmd; | |
51 | short int has_arg; | |
52 | short int is_mail_cmd; | |
53 | } smtp_cmd_list; | |
54 | ||
55 | /* Codes for identifying commands. We order them so that those that come first | |
56 | are those for which synchronization is always required. Checking this can help | |
57 | block some spam. */ | |
58 | ||
59 | enum { | |
60 | /* These commands are required to be synchronized, i.e. to be the last in a | |
61 | block of commands when pipelining. */ | |
62 | ||
63 | HELO_CMD, EHLO_CMD, DATA_CMD, /* These are listed in the pipelining */ | |
64 | VRFY_CMD, EXPN_CMD, NOOP_CMD, /* RFC as requiring synchronization */ | |
65 | ETRN_CMD, /* This by analogy with TURN from the RFC */ | |
66 | STARTTLS_CMD, /* Required by the STARTTLS RFC */ | |
67 | ||
68 | /* This is a dummy to identify the non-sync commands when pipelining */ | |
69 | ||
70 | NON_SYNC_CMD_PIPELINING, | |
71 | ||
72 | /* These commands need not be synchronized when pipelining */ | |
73 | ||
74 | MAIL_CMD, RCPT_CMD, RSET_CMD, | |
75 | ||
76 | /* This is a dummy to identify the non-sync commands when not pipelining */ | |
77 | ||
78 | NON_SYNC_CMD_NON_PIPELINING, | |
79 | ||
80 | /* I have been unable to find a statement about the use of pipelining | |
81 | with AUTH, so to be on the safe side it is here, though I kind of feel | |
82 | it should be up there with the synchronized commands. */ | |
83 | ||
84 | AUTH_CMD, | |
85 | ||
86 | /* I'm not sure about these, but I don't think they matter. */ | |
87 | ||
88 | QUIT_CMD, HELP_CMD, | |
89 | ||
90 | /* These are specials that don't correspond to actual commands */ | |
91 | ||
92 | EOF_CMD, OTHER_CMD, BADARG_CMD, BADCHAR_CMD, BADSYN_CMD, | |
93 | TOO_MANY_NONMAIL_CMD }; | |
94 | ||
95 | ||
96 | ||
97 | /************************************************* | |
98 | * Local static variables * | |
99 | *************************************************/ | |
100 | ||
101 | static auth_instance *authenticated_by; | |
102 | static BOOL auth_advertised; | |
103 | #ifdef SUPPORT_TLS | |
104 | static BOOL tls_advertised; | |
105 | #endif | |
106 | static BOOL esmtp; | |
107 | static BOOL helo_required = FALSE; | |
108 | static BOOL helo_verify = FALSE; | |
109 | static BOOL helo_seen; | |
110 | static BOOL helo_accept_junk; | |
111 | static BOOL count_nonmail; | |
112 | static BOOL pipelining_advertised; | |
113 | static int nonmail_command_count; | |
114 | static int synprot_error_count; | |
115 | static int unknown_command_count; | |
116 | static int sync_cmd_limit; | |
117 | static int smtp_write_error = 0; | |
118 | ||
119 | static uschar *smtp_data; | |
120 | ||
121 | static uschar *cmd_buffer; | |
122 | ||
123 | /* We need to know the position of RSET, HELO, EHLO, AUTH, and STARTTLS. Their | |
124 | final fields of all except AUTH are forced TRUE at the start of a new message | |
125 | setup, to allow one of each between messages that is not counted as a nonmail | |
126 | command. (In fact, only one of HELO/EHLO is not counted.) Also, we have to | |
127 | allow a new EHLO after starting up TLS. | |
128 | ||
129 | AUTH is "falsely" labelled as a mail command initially, so that it doesn't get | |
130 | counted. However, the flag is changed when AUTH is received, so that multiple | |
131 | failing AUTHs will eventually hit the limit. After a successful AUTH, another | |
132 | AUTH is already forbidden. After a TLS session is started, AUTH's flag is again | |
133 | forced TRUE, to allow for the re-authentication that can happen at that point. | |
134 | ||
135 | QUIT is also "falsely" labelled as a mail command so that it doesn't up the | |
136 | count of non-mail commands and possibly provoke an error. */ | |
137 | ||
138 | static smtp_cmd_list cmd_list[] = { | |
139 | { "rset", sizeof("rset")-1, RSET_CMD, FALSE, FALSE }, /* First */ | |
140 | { "helo", sizeof("helo")-1, HELO_CMD, TRUE, FALSE }, | |
141 | { "ehlo", sizeof("ehlo")-1, EHLO_CMD, TRUE, FALSE }, | |
142 | { "auth", sizeof("auth")-1, AUTH_CMD, TRUE, TRUE }, | |
143 | #ifdef SUPPORT_TLS | |
144 | { "starttls", sizeof("starttls")-1, STARTTLS_CMD, FALSE, FALSE }, | |
145 | #endif | |
146 | ||
147 | /* If you change anything above here, also fix the definitions below. */ | |
148 | ||
149 | { "mail from:", sizeof("mail from:")-1, MAIL_CMD, TRUE, TRUE }, | |
150 | { "rcpt to:", sizeof("rcpt to:")-1, RCPT_CMD, TRUE, TRUE }, | |
151 | { "data", sizeof("data")-1, DATA_CMD, FALSE, TRUE }, | |
152 | { "quit", sizeof("quit")-1, QUIT_CMD, FALSE, TRUE }, | |
153 | { "noop", sizeof("noop")-1, NOOP_CMD, TRUE, FALSE }, | |
154 | { "etrn", sizeof("etrn")-1, ETRN_CMD, TRUE, FALSE }, | |
155 | { "vrfy", sizeof("vrfy")-1, VRFY_CMD, TRUE, FALSE }, | |
156 | { "expn", sizeof("expn")-1, EXPN_CMD, TRUE, FALSE }, | |
157 | { "help", sizeof("help")-1, HELP_CMD, TRUE, FALSE } | |
158 | }; | |
159 | ||
160 | static smtp_cmd_list *cmd_list_end = | |
161 | cmd_list + sizeof(cmd_list)/sizeof(smtp_cmd_list); | |
162 | ||
163 | #define CMD_LIST_RSET 0 | |
164 | #define CMD_LIST_HELO 1 | |
165 | #define CMD_LIST_EHLO 2 | |
166 | #define CMD_LIST_AUTH 3 | |
167 | #define CMD_LIST_STARTTLS 4 | |
168 | ||
169 | static uschar *protocols[] = { | |
981756db PH |
170 | US"local-smtp", /* HELO */ |
171 | US"local-smtps", /* The rare case EHLO->STARTTLS->HELO */ | |
172 | US"local-esmtp", /* EHLO */ | |
173 | US"local-esmtps", /* EHLO->STARTTLS->EHLO */ | |
174 | US"local-esmtpa", /* EHLO->AUTH */ | |
175 | US"local-esmtpsa" /* EHLO->STARTTLS->EHLO->AUTH */ | |
059ec3d9 PH |
176 | }; |
177 | ||
178 | #define pnormal 0 | |
981756db PH |
179 | #define pextend 2 |
180 | #define pcrpted 1 /* added to pextend or pnormal */ | |
181 | #define pauthed 2 /* added to pextend */ | |
059ec3d9 PH |
182 | #define pnlocal 6 /* offset to remove "local" */ |
183 | ||
184 | /* When reading SMTP from a remote host, we have to use our own versions of the | |
185 | C input-reading functions, in order to be able to flush the SMTP output only | |
186 | when about to read more data from the socket. This is the only way to get | |
187 | optimal performance when the client is using pipelining. Flushing for every | |
188 | command causes a separate packet and reply packet each time; saving all the | |
189 | responses up (when pipelining) combines them into one packet and one response. | |
190 | ||
191 | For simplicity, these functions are used for *all* SMTP input, not only when | |
192 | receiving over a socket. However, after setting up a secure socket (SSL), input | |
193 | is read via the OpenSSL library, and another set of functions is used instead | |
194 | (see tls.c). | |
195 | ||
196 | These functions are set in the receive_getc etc. variables and called with the | |
197 | same interface as the C functions. However, since there can only ever be | |
198 | one incoming SMTP call, we just use a single buffer and flags. There is no need | |
199 | to implement a complicated private FILE-like structure.*/ | |
200 | ||
201 | static uschar *smtp_inbuffer; | |
202 | static uschar *smtp_inptr; | |
203 | static uschar *smtp_inend; | |
204 | static int smtp_had_eof; | |
205 | static int smtp_had_error; | |
206 | ||
207 | ||
208 | /************************************************* | |
209 | * SMTP version of getc() * | |
210 | *************************************************/ | |
211 | ||
212 | /* This gets the next byte from the SMTP input buffer. If the buffer is empty, | |
213 | it flushes the output, and refills the buffer, with a timeout. The signal | |
214 | handler is set appropriately by the calling function. This function is not used | |
215 | after a connection has negotated itself into an TLS/SSL state. | |
216 | ||
217 | Arguments: none | |
218 | Returns: the next character or EOF | |
219 | */ | |
220 | ||
221 | int | |
222 | smtp_getc(void) | |
223 | { | |
224 | if (smtp_inptr >= smtp_inend) | |
225 | { | |
226 | int rc, save_errno; | |
227 | fflush(smtp_out); | |
228 | if (smtp_receive_timeout > 0) alarm(smtp_receive_timeout); | |
229 | rc = read(fileno(smtp_in), smtp_inbuffer, in_buffer_size); | |
230 | save_errno = errno; | |
231 | alarm(0); | |
232 | if (rc <= 0) | |
233 | { | |
234 | /* Must put the error text in fixed store, because this might be during | |
235 | header reading, where it releases unused store above the header. */ | |
236 | if (rc < 0) | |
237 | { | |
238 | smtp_had_error = save_errno; | |
239 | smtp_read_error = string_copy_malloc( | |
240 | string_sprintf(" (error: %s)", strerror(save_errno))); | |
241 | } | |
242 | else smtp_had_eof = 1; | |
243 | return EOF; | |
244 | } | |
245 | smtp_inend = smtp_inbuffer + rc; | |
246 | smtp_inptr = smtp_inbuffer; | |
247 | } | |
248 | return *smtp_inptr++; | |
249 | } | |
250 | ||
251 | ||
252 | ||
253 | /************************************************* | |
254 | * SMTP version of ungetc() * | |
255 | *************************************************/ | |
256 | ||
257 | /* Puts a character back in the input buffer. Only ever | |
258 | called once. | |
259 | ||
260 | Arguments: | |
261 | ch the character | |
262 | ||
263 | Returns: the character | |
264 | */ | |
265 | ||
266 | int | |
267 | smtp_ungetc(int ch) | |
268 | { | |
269 | *(--smtp_inptr) = ch; | |
270 | return ch; | |
271 | } | |
272 | ||
273 | ||
274 | ||
275 | ||
276 | /************************************************* | |
277 | * SMTP version of feof() * | |
278 | *************************************************/ | |
279 | ||
280 | /* Tests for a previous EOF | |
281 | ||
282 | Arguments: none | |
283 | Returns: non-zero if the eof flag is set | |
284 | */ | |
285 | ||
286 | int | |
287 | smtp_feof(void) | |
288 | { | |
289 | return smtp_had_eof; | |
290 | } | |
291 | ||
292 | ||
293 | ||
294 | ||
295 | /************************************************* | |
296 | * SMTP version of ferror() * | |
297 | *************************************************/ | |
298 | ||
299 | /* Tests for a previous read error, and returns with errno | |
300 | restored to what it was when the error was detected. | |
301 | ||
302 | Arguments: none | |
303 | Returns: non-zero if the error flag is set | |
304 | */ | |
305 | ||
306 | int | |
307 | smtp_ferror(void) | |
308 | { | |
309 | errno = smtp_had_error; | |
310 | return smtp_had_error; | |
311 | } | |
312 | ||
313 | ||
314 | ||
315 | ||
316 | /************************************************* | |
317 | * Write formatted string to SMTP channel * | |
318 | *************************************************/ | |
319 | ||
320 | /* This is a separate function so that we don't have to repeat everything for | |
321 | TLS support or debugging. It is global so that the daemon and the | |
322 | authentication functions can use it. It does not return any error indication, | |
323 | because major problems such as dropped connections won't show up till an output | |
324 | flush for non-TLS connections. The smtp_fflush() function is available for | |
325 | checking that: for convenience, TLS output errors are remembered here so that | |
326 | they are also picked up later by smtp_fflush(). | |
327 | ||
328 | Arguments: | |
329 | format format string | |
330 | ... optional arguments | |
331 | ||
332 | Returns: nothing | |
333 | */ | |
334 | ||
335 | void | |
336 | smtp_printf(char *format, ...) | |
337 | { | |
338 | va_list ap; | |
339 | ||
340 | DEBUG(D_receive) | |
341 | { | |
342 | va_start(ap, format); | |
343 | (void) string_vformat(big_buffer, big_buffer_size, format, ap); | |
344 | debug_printf("SMTP>> %s", big_buffer); | |
345 | } | |
346 | ||
347 | va_start(ap, format); | |
348 | ||
349 | /* If in a TLS session we have to format the string, and then write it using a | |
350 | TLS function. */ | |
351 | ||
352 | #ifdef SUPPORT_TLS | |
353 | if (tls_active >= 0) | |
354 | { | |
355 | if (!string_vformat(big_buffer, big_buffer_size, format, ap)) | |
356 | { | |
357 | log_write(0, LOG_MAIN|LOG_PANIC, "string too large in smtp_printf"); | |
358 | smtp_closedown(US"Unexpected error"); | |
359 | exim_exit(EXIT_FAILURE); | |
360 | } | |
361 | if (tls_write(big_buffer, Ustrlen(big_buffer)) < 0) smtp_write_error = -1; | |
362 | } | |
363 | else | |
364 | #endif | |
365 | ||
366 | /* Otherwise, just use the standard library function. */ | |
367 | ||
368 | if (vfprintf(smtp_out, format, ap) < 0) smtp_write_error = -1; | |
369 | va_end(ap); | |
370 | } | |
371 | ||
372 | ||
373 | ||
374 | /************************************************* | |
375 | * Flush SMTP out and check for error * | |
376 | *************************************************/ | |
377 | ||
378 | /* This function isn't currently used within Exim (it detects errors when it | |
379 | tries to read the next SMTP input), but is available for use in local_scan(). | |
380 | For non-TLS connections, it flushes the output and checks for errors. For | |
381 | TLS-connections, it checks for a previously-detected TLS write error. | |
382 | ||
383 | Arguments: none | |
384 | Returns: 0 for no error; -1 after an error | |
385 | */ | |
386 | ||
387 | int | |
388 | smtp_fflush(void) | |
389 | { | |
390 | if (tls_active < 0 && fflush(smtp_out) != 0) smtp_write_error = -1; | |
391 | return smtp_write_error; | |
392 | } | |
393 | ||
394 | ||
395 | ||
396 | /************************************************* | |
397 | * SMTP command read timeout * | |
398 | *************************************************/ | |
399 | ||
400 | /* Signal handler for timing out incoming SMTP commands. This attempts to | |
401 | finish off tidily. | |
402 | ||
403 | Argument: signal number (SIGALRM) | |
404 | Returns: nothing | |
405 | */ | |
406 | ||
407 | static void | |
408 | command_timeout_handler(int sig) | |
409 | { | |
410 | sig = sig; /* Keep picky compilers happy */ | |
411 | log_write(L_lost_incoming_connection, | |
412 | LOG_MAIN, "SMTP command timeout on%s connection from %s", | |
413 | (tls_active >= 0)? " TLS" : "", | |
414 | host_and_ident(FALSE)); | |
415 | if (smtp_batched_input) | |
416 | moan_smtp_batch(NULL, "421 SMTP command timeout"); /* Does not return */ | |
417 | smtp_printf("421 %s: SMTP command timeout - closing connection\r\n", | |
418 | smtp_active_hostname); | |
419 | mac_smtp_fflush(); | |
420 | exim_exit(EXIT_FAILURE); | |
421 | } | |
422 | ||
423 | ||
424 | ||
425 | /************************************************* | |
426 | * SIGTERM received * | |
427 | *************************************************/ | |
428 | ||
429 | /* Signal handler for handling SIGTERM. Again, try to finish tidily. | |
430 | ||
431 | Argument: signal number (SIGTERM) | |
432 | Returns: nothing | |
433 | */ | |
434 | ||
435 | static void | |
436 | command_sigterm_handler(int sig) | |
437 | { | |
438 | sig = sig; /* Keep picky compilers happy */ | |
439 | log_write(0, LOG_MAIN, "%s closed after SIGTERM", smtp_get_connection_info()); | |
440 | if (smtp_batched_input) | |
441 | moan_smtp_batch(NULL, "421 SIGTERM received"); /* Does not return */ | |
442 | smtp_printf("421 %s: Service not available - closing connection\r\n", | |
443 | smtp_active_hostname); | |
444 | exim_exit(EXIT_FAILURE); | |
445 | } | |
446 | ||
447 | ||
448 | ||
449 | /************************************************* | |
450 | * Read one command line * | |
451 | *************************************************/ | |
452 | ||
453 | /* Strictly, SMTP commands coming over the net are supposed to end with CRLF. | |
454 | There are sites that don't do this, and in any case internal SMTP probably | |
455 | should check only for LF. Consequently, we check here for LF only. The line | |
456 | ends up with [CR]LF removed from its end. If we get an overlong line, treat as | |
457 | an unknown command. The command is read into the static cmd_buffer. | |
458 | ||
459 | The character reading routine sets up a timeout for each block actually read | |
460 | from the input (which may contain more than one command). We set up a special | |
461 | signal handler that closes down the session on a timeout. Control does not | |
462 | return when it runs. | |
463 | ||
464 | Arguments: | |
465 | check_sync if TRUE, check synchronization rules if global option is TRUE | |
466 | ||
467 | Returns: a code identifying the command (enumerated above) | |
468 | */ | |
469 | ||
470 | static int | |
471 | smtp_read_command(BOOL check_sync) | |
472 | { | |
473 | int c; | |
474 | int ptr = 0; | |
475 | smtp_cmd_list *p; | |
476 | BOOL hadnull = FALSE; | |
477 | ||
478 | os_non_restarting_signal(SIGALRM, command_timeout_handler); | |
479 | ||
480 | while ((c = (receive_getc)()) != '\n' && c != EOF) | |
481 | { | |
482 | if (ptr >= cmd_buffer_size) | |
483 | { | |
484 | os_non_restarting_signal(SIGALRM, sigalrm_handler); | |
485 | return OTHER_CMD; | |
486 | } | |
487 | if (c == 0) | |
488 | { | |
489 | hadnull = TRUE; | |
490 | c = '?'; | |
491 | } | |
492 | cmd_buffer[ptr++] = c; | |
493 | } | |
494 | ||
495 | receive_linecount++; /* For BSMTP errors */ | |
496 | os_non_restarting_signal(SIGALRM, sigalrm_handler); | |
497 | ||
498 | /* If hit end of file, return pseudo EOF command. Whether we have a | |
499 | part-line already read doesn't matter, since this is an error state. */ | |
500 | ||
501 | if (c == EOF) return EOF_CMD; | |
502 | ||
503 | /* Remove any CR and white space at the end of the line, and terminate the | |
504 | string. */ | |
505 | ||
506 | while (ptr > 0 && isspace(cmd_buffer[ptr-1])) ptr--; | |
507 | cmd_buffer[ptr] = 0; | |
508 | ||
509 | DEBUG(D_receive) debug_printf("SMTP<< %s\n", cmd_buffer); | |
510 | ||
511 | /* NULLs are not allowed in SMTP commands */ | |
512 | ||
513 | if (hadnull) return BADCHAR_CMD; | |
514 | ||
515 | /* Scan command list and return identity, having set the data pointer | |
516 | to the start of the actual data characters. Check for SMTP synchronization | |
517 | if required. */ | |
518 | ||
519 | for (p = cmd_list; p < cmd_list_end; p++) | |
520 | { | |
521 | if (strncmpic(cmd_buffer, US p->name, p->len) == 0) | |
522 | { | |
523 | if (smtp_inptr < smtp_inend && /* Outstanding input */ | |
524 | p->cmd < sync_cmd_limit && /* Command should sync */ | |
525 | check_sync && /* Local flag set */ | |
526 | smtp_enforce_sync && /* Global flag set */ | |
527 | sender_host_address != NULL && /* Not local input */ | |
528 | !sender_host_notsocket) /* Really is a socket */ | |
529 | return BADSYN_CMD; | |
530 | ||
531 | /* Point after the command, but don't skip over leading spaces till after | |
532 | the following test, so that if it fails, the command name can easily be | |
533 | logged. */ | |
534 | ||
535 | smtp_data = cmd_buffer + p->len; | |
536 | ||
537 | /* Count non-mail commands from those hosts that are controlled in this | |
538 | way. The default is all hosts. We don't waste effort checking the list | |
539 | until we get a non-mail command, but then cache the result to save checking | |
540 | again. If there's a DEFER while checking the host, assume it's in the list. | |
541 | ||
542 | Note that one instance of RSET, EHLO/HELO, and STARTTLS is allowed at the | |
543 | start of each incoming message by fiddling with the value in the table. */ | |
544 | ||
545 | if (!p->is_mail_cmd) | |
546 | { | |
547 | if (count_nonmail == TRUE_UNSET) count_nonmail = | |
548 | verify_check_host(&smtp_accept_max_nonmail_hosts) != FAIL; | |
549 | if (count_nonmail && ++nonmail_command_count > smtp_accept_max_nonmail) | |
550 | return TOO_MANY_NONMAIL_CMD; | |
551 | } | |
552 | ||
553 | /* Get the data pointer over leading spaces and return; if there is no data | |
554 | for a command that expects it, we give the error centrally here. */ | |
555 | ||
556 | while (isspace(*smtp_data)) smtp_data++; | |
557 | return (p->has_arg || *smtp_data == 0)? p->cmd : BADARG_CMD; | |
558 | } | |
559 | } | |
560 | ||
561 | /* Enforce synchronization for unknown commands */ | |
562 | ||
563 | if (smtp_inptr < smtp_inend && /* Outstanding input */ | |
564 | check_sync && /* Local flag set */ | |
565 | smtp_enforce_sync && /* Global flag set */ | |
566 | sender_host_address != NULL && /* Not local input */ | |
567 | !sender_host_notsocket) /* Really is a socket */ | |
568 | return BADSYN_CMD; | |
569 | ||
570 | return OTHER_CMD; | |
571 | } | |
572 | ||
573 | ||
574 | ||
575 | /************************************************* | |
576 | * Forced closedown of call * | |
577 | *************************************************/ | |
578 | ||
579 | /* This function is called from log.c when Exim is dying because of a serious | |
580 | disaster, and also from some other places. If an incoming non-batched SMTP | |
581 | channel is open, it swallows the rest of the incoming message if in the DATA | |
582 | phase, sends the reply string, and gives an error to all subsequent commands | |
583 | except QUIT. The existence of an SMTP call is detected by the non-NULLness of | |
584 | smtp_in. | |
585 | ||
586 | Argument: SMTP reply string to send, excluding the code | |
587 | Returns: nothing | |
588 | */ | |
589 | ||
590 | void | |
591 | smtp_closedown(uschar *message) | |
592 | { | |
593 | if (smtp_in == NULL || smtp_batched_input) return; | |
594 | receive_swallow_smtp(); | |
595 | smtp_printf("421 %s\r\n", message); | |
596 | ||
597 | for (;;) | |
598 | { | |
599 | switch(smtp_read_command(FALSE)) | |
600 | { | |
601 | case EOF_CMD: | |
602 | return; | |
603 | ||
604 | case QUIT_CMD: | |
605 | smtp_printf("221 %s closing connection\r\n", smtp_active_hostname); | |
606 | mac_smtp_fflush(); | |
607 | return; | |
608 | ||
609 | case RSET_CMD: | |
610 | smtp_printf("250 Reset OK\r\n"); | |
611 | break; | |
612 | ||
613 | default: | |
614 | smtp_printf("421 %s\r\n", message); | |
615 | break; | |
616 | } | |
617 | } | |
618 | } | |
619 | ||
620 | ||
621 | ||
622 | ||
623 | /************************************************* | |
624 | * Set up connection info for logging * | |
625 | *************************************************/ | |
626 | ||
627 | /* This function is called when logging information about an SMTP connection. | |
628 | It sets up appropriate source information, depending on the type of connection. | |
629 | ||
630 | Argument: none | |
631 | Returns: a string describing the connection | |
632 | */ | |
633 | ||
634 | uschar * | |
635 | smtp_get_connection_info(void) | |
636 | { | |
637 | if (host_checking) | |
638 | return string_sprintf("SMTP connection from %s", sender_fullhost); | |
639 | ||
640 | if (sender_host_unknown || sender_host_notsocket) | |
641 | return string_sprintf("SMTP connection from %s", sender_ident); | |
642 | ||
643 | if (is_inetd) | |
644 | return string_sprintf("SMTP connection from %s (via inetd)", sender_fullhost); | |
645 | ||
646 | if ((log_extra_selector & LX_incoming_interface) != 0 && | |
647 | interface_address != NULL) | |
648 | return string_sprintf("SMTP connection from %s I=[%s]:%d", sender_fullhost, | |
649 | interface_address, interface_port); | |
650 | ||
651 | return string_sprintf("SMTP connection from %s", sender_fullhost); | |
652 | } | |
653 | ||
654 | ||
655 | ||
656 | /************************************************* | |
657 | * Check HELO line and set sender_helo_name * | |
658 | *************************************************/ | |
659 | ||
660 | /* Check the format of a HELO line. The data for HELO/EHLO is supposed to be | |
661 | the domain name of the sending host, or an ip literal in square brackets. The | |
662 | arrgument is placed in sender_helo_name, which is in malloc store, because it | |
663 | must persist over multiple incoming messages. If helo_accept_junk is set, this | |
664 | host is permitted to send any old junk (needed for some broken hosts). | |
665 | Otherwise, helo_allow_chars can be used for rogue characters in general | |
666 | (typically people want to let in underscores). | |
667 | ||
668 | Argument: | |
669 | s the data portion of the line (already past any white space) | |
670 | ||
671 | Returns: TRUE or FALSE | |
672 | */ | |
673 | ||
674 | static BOOL | |
675 | check_helo(uschar *s) | |
676 | { | |
677 | uschar *start = s; | |
678 | uschar *end = s + Ustrlen(s); | |
679 | BOOL yield = helo_accept_junk; | |
680 | ||
681 | /* Discard any previous helo name */ | |
682 | ||
683 | if (sender_helo_name != NULL) | |
684 | { | |
685 | store_free(sender_helo_name); | |
686 | sender_helo_name = NULL; | |
687 | } | |
688 | ||
689 | /* Skip tests if junk is permitted. */ | |
690 | ||
691 | if (!yield) | |
692 | { | |
693 | /* Allow the new standard form for IPv6 address literals, namely, | |
694 | [IPv6:....], and because someone is bound to use it, allow an equivalent | |
695 | IPv4 form. Allow plain addresses as well. */ | |
696 | ||
697 | if (*s == '[') | |
698 | { | |
699 | if (end[-1] == ']') | |
700 | { | |
701 | end[-1] = 0; | |
702 | if (strncmpic(s, US"[IPv6:", 6) == 0) | |
703 | yield = (string_is_ip_address(s+6, NULL) == 6); | |
704 | else if (strncmpic(s, US"[IPv4:", 6) == 0) | |
705 | yield = (string_is_ip_address(s+6, NULL) == 4); | |
706 | else | |
707 | yield = (string_is_ip_address(s+1, NULL) != 0); | |
708 | end[-1] = ']'; | |
709 | } | |
710 | } | |
711 | ||
712 | /* Non-literals must be alpha, dot, hyphen, plus any non-valid chars | |
713 | that have been configured (usually underscore - sigh). */ | |
714 | ||
715 | else if (*s != 0) | |
716 | { | |
717 | yield = TRUE; | |
718 | while (*s != 0) | |
719 | { | |
720 | if (!isalnum(*s) && *s != '.' && *s != '-' && | |
721 | Ustrchr(helo_allow_chars, *s) == NULL) | |
722 | { | |
723 | yield = FALSE; | |
724 | break; | |
725 | } | |
726 | s++; | |
727 | } | |
728 | } | |
729 | } | |
730 | ||
731 | /* Save argument if OK */ | |
732 | ||
733 | if (yield) sender_helo_name = string_copy_malloc(start); | |
734 | return yield; | |
735 | } | |
736 | ||
737 | ||
738 | ||
739 | ||
740 | ||
741 | /************************************************* | |
742 | * Extract SMTP command option * | |
743 | *************************************************/ | |
744 | ||
745 | /* This function picks the next option setting off the end of smtp_data. It | |
746 | is called for MAIL FROM and RCPT TO commands, to pick off the optional ESMTP | |
747 | things that can appear there. | |
748 | ||
749 | Arguments: | |
750 | name point this at the name | |
751 | value point this at the data string | |
752 | ||
753 | Returns: TRUE if found an option | |
754 | */ | |
755 | ||
756 | static BOOL | |
757 | extract_option(uschar **name, uschar **value) | |
758 | { | |
759 | uschar *n; | |
760 | uschar *v = smtp_data + Ustrlen(smtp_data) -1; | |
761 | while (isspace(*v)) v--; | |
762 | v[1] = 0; | |
763 | ||
764 | while (v > smtp_data && *v != '=' && !isspace(*v)) v--; | |
765 | if (*v != '=') return FALSE; | |
766 | ||
767 | n = v; | |
768 | while(isalpha(n[-1])) n--; | |
769 | ||
770 | if (n[-1] != ' ') return FALSE; | |
771 | ||
772 | n[-1] = 0; | |
773 | *name = n; | |
774 | *v++ = 0; | |
775 | *value = v; | |
776 | return TRUE; | |
777 | } | |
778 | ||
779 | ||
780 | ||
781 | ||
782 | ||
783 | ||
784 | ||
785 | /************************************************* | |
786 | * Reset for new message * | |
787 | *************************************************/ | |
788 | ||
789 | /* This function is called whenever the SMTP session is reset from | |
790 | within either of the setup functions. | |
791 | ||
792 | Argument: the stacking pool storage reset point | |
793 | Returns: nothing | |
794 | */ | |
795 | ||
796 | static void | |
797 | smtp_reset(void *reset_point) | |
798 | { | |
799 | int i; | |
800 | store_reset(reset_point); | |
801 | recipients_list = NULL; | |
802 | rcpt_count = rcpt_defer_count = rcpt_fail_count = | |
803 | raw_recipients_count = recipients_count = recipients_list_max = 0; | |
804 | message_size = -1; | |
805 | acl_warn_headers = NULL; | |
806 | queue_only_policy = FALSE; | |
69358f02 PH |
807 | deliver_freeze = FALSE; /* Can be set by ACL */ |
808 | submission_mode = FALSE; /* Can be set by ACL */ | |
809 | active_local_from_check = local_from_check; /* Can be set by ACL */ | |
810 | active_local_sender_retain = local_sender_retain; /* Can be set by ACL */ | |
059ec3d9 PH |
811 | sender_address = NULL; |
812 | raw_sender = NULL; /* After SMTP rewrite, before qualifying */ | |
813 | sender_address_unrewritten = NULL; /* Set only after verify rewrite */ | |
814 | sender_verified_list = NULL; /* No senders verified */ | |
815 | memset(sender_address_cache, 0, sizeof(sender_address_cache)); | |
816 | memset(sender_domain_cache, 0, sizeof(sender_domain_cache)); | |
817 | authenticated_sender = NULL; | |
818 | body_linecount = body_zerocount = 0; | |
819 | ||
820 | for (i = 0; i < ACL_M_MAX; i++) acl_var[ACL_C_MAX + i] = NULL; | |
821 | ||
822 | /* The message body variables use malloc store. They may be set if this is | |
823 | not the first message in an SMTP session and the previous message caused them | |
824 | to be referenced in an ACL. */ | |
825 | ||
826 | if (message_body != NULL) | |
827 | { | |
828 | store_free(message_body); | |
829 | message_body = NULL; | |
830 | } | |
831 | ||
832 | if (message_body_end != NULL) | |
833 | { | |
834 | store_free(message_body_end); | |
835 | message_body_end = NULL; | |
836 | } | |
837 | ||
838 | /* Warning log messages are also saved in malloc store. They are saved to avoid | |
839 | repetition in the same message, but it seems right to repeat them for different | |
840 | messagess. */ | |
841 | ||
842 | while (acl_warn_logged != NULL) | |
843 | { | |
844 | string_item *this = acl_warn_logged; | |
845 | acl_warn_logged = acl_warn_logged->next; | |
846 | store_free(this); | |
847 | } | |
848 | } | |
849 | ||
850 | ||
851 | ||
852 | ||
853 | ||
854 | /************************************************* | |
855 | * Initialize for incoming batched SMTP message * | |
856 | *************************************************/ | |
857 | ||
858 | /* This function is called from smtp_setup_msg() in the case when | |
859 | smtp_batched_input is true. This happens when -bS is used to pass a whole batch | |
860 | of messages in one file with SMTP commands between them. All errors must be | |
861 | reported by sending a message, and only MAIL FROM, RCPT TO, and DATA are | |
862 | relevant. After an error on a sender, or an invalid recipient, the remainder | |
863 | of the message is skipped. The value of received_protocol is already set. | |
864 | ||
865 | Argument: none | |
866 | Returns: > 0 message successfully started (reached DATA) | |
867 | = 0 QUIT read or end of file reached | |
868 | < 0 should not occur | |
869 | */ | |
870 | ||
871 | static int | |
872 | smtp_setup_batch_msg(void) | |
873 | { | |
874 | int done = 0; | |
875 | void *reset_point = store_get(0); | |
876 | ||
877 | /* Save the line count at the start of each transaction - single commands | |
878 | like HELO and RSET count as whole transactions. */ | |
879 | ||
880 | bsmtp_transaction_linecount = receive_linecount; | |
881 | ||
882 | if ((receive_feof)()) return 0; /* Treat EOF as QUIT */ | |
883 | ||
884 | smtp_reset(reset_point); /* Reset for start of message */ | |
885 | ||
886 | /* Deal with SMTP commands. This loop is exited by setting done to a POSITIVE | |
887 | value. The values are 2 larger than the required yield of the function. */ | |
888 | ||
889 | while (done <= 0) | |
890 | { | |
891 | uschar *errmess; | |
892 | uschar *recipient = NULL; | |
893 | int start, end, sender_domain, recipient_domain; | |
894 | ||
895 | switch(smtp_read_command(FALSE)) | |
896 | { | |
897 | /* The HELO/EHLO commands set sender_address_helo if they have | |
898 | valid data; otherwise they are ignored, except that they do | |
899 | a reset of the state. */ | |
900 | ||
901 | case HELO_CMD: | |
902 | case EHLO_CMD: | |
903 | ||
904 | check_helo(smtp_data); | |
905 | /* Fall through */ | |
906 | ||
907 | case RSET_CMD: | |
908 | smtp_reset(reset_point); | |
909 | bsmtp_transaction_linecount = receive_linecount; | |
910 | break; | |
911 | ||
912 | ||
913 | /* The MAIL FROM command requires an address as an operand. All we | |
914 | do here is to parse it for syntactic correctness. The form "<>" is | |
915 | a special case which converts into an empty string. The start/end | |
916 | pointers in the original are not used further for this address, as | |
917 | it is the canonical extracted address which is all that is kept. */ | |
918 | ||
919 | case MAIL_CMD: | |
920 | if (sender_address != NULL) | |
921 | /* The function moan_smtp_batch() does not return. */ | |
922 | moan_smtp_batch(cmd_buffer, "503 Sender already given"); | |
923 | ||
924 | if (smtp_data[0] == 0) | |
925 | /* The function moan_smtp_batch() does not return. */ | |
926 | moan_smtp_batch(cmd_buffer, "501 MAIL FROM must have an address operand"); | |
927 | ||
928 | /* Reset to start of message */ | |
929 | ||
930 | smtp_reset(reset_point); | |
931 | ||
932 | /* Apply SMTP rewrite */ | |
933 | ||
934 | raw_sender = ((rewrite_existflags & rewrite_smtp) != 0)? | |
935 | rewrite_one(smtp_data, rewrite_smtp|rewrite_smtp_sender, NULL, FALSE, | |
936 | US"", global_rewrite_rules) : smtp_data; | |
937 | ||
938 | /* Extract the address; the TRUE flag allows <> as valid */ | |
939 | ||
940 | raw_sender = | |
941 | parse_extract_address(raw_sender, &errmess, &start, &end, &sender_domain, | |
942 | TRUE); | |
943 | ||
944 | if (raw_sender == NULL) | |
945 | /* The function moan_smtp_batch() does not return. */ | |
946 | moan_smtp_batch(cmd_buffer, "501 %s", errmess); | |
947 | ||
948 | sender_address = string_copy(raw_sender); | |
949 | ||
950 | /* Qualify unqualified sender addresses if permitted to do so. */ | |
951 | ||
952 | if (sender_domain == 0 && sender_address[0] != 0 && sender_address[0] != '@') | |
953 | { | |
954 | if (allow_unqualified_sender) | |
955 | { | |
956 | sender_address = rewrite_address_qualify(sender_address, FALSE); | |
957 | DEBUG(D_receive) debug_printf("unqualified address %s accepted " | |
958 | "and rewritten\n", raw_sender); | |
959 | } | |
960 | /* The function moan_smtp_batch() does not return. */ | |
961 | else moan_smtp_batch(cmd_buffer, "501 sender address must contain " | |
962 | "a domain"); | |
963 | } | |
964 | break; | |
965 | ||
966 | ||
967 | /* The RCPT TO command requires an address as an operand. All we do | |
968 | here is to parse it for syntactic correctness. There may be any number | |
969 | of RCPT TO commands, specifying multiple senders. We build them all into | |
970 | a data structure that is in argc/argv format. The start/end values | |
971 | given by parse_extract_address are not used, as we keep only the | |
972 | extracted address. */ | |
973 | ||
974 | case RCPT_CMD: | |
975 | if (sender_address == NULL) | |
976 | /* The function moan_smtp_batch() does not return. */ | |
977 | moan_smtp_batch(cmd_buffer, "503 No sender yet given"); | |
978 | ||
979 | if (smtp_data[0] == 0) | |
980 | /* The function moan_smtp_batch() does not return. */ | |
981 | moan_smtp_batch(cmd_buffer, "501 RCPT TO must have an address operand"); | |
982 | ||
983 | /* Check maximum number allowed */ | |
984 | ||
985 | if (recipients_max > 0 && recipients_count + 1 > recipients_max) | |
986 | /* The function moan_smtp_batch() does not return. */ | |
987 | moan_smtp_batch(cmd_buffer, "%s too many recipients", | |
988 | recipients_max_reject? "552": "452"); | |
989 | ||
990 | /* Apply SMTP rewrite, then extract address. Don't allow "<>" as a | |
991 | recipient address */ | |
992 | ||
993 | recipient = ((rewrite_existflags & rewrite_smtp) != 0)? | |
994 | rewrite_one(smtp_data, rewrite_smtp, NULL, FALSE, US"", | |
995 | global_rewrite_rules) : smtp_data; | |
996 | ||
997 | /* rfc821_domains = TRUE; << no longer needed */ | |
998 | recipient = parse_extract_address(recipient, &errmess, &start, &end, | |
999 | &recipient_domain, FALSE); | |
1000 | /* rfc821_domains = FALSE; << no longer needed */ | |
1001 | ||
1002 | if (recipient == NULL) | |
1003 | /* The function moan_smtp_batch() does not return. */ | |
1004 | moan_smtp_batch(cmd_buffer, "501 %s", errmess); | |
1005 | ||
1006 | /* If the recipient address is unqualified, qualify it if permitted. Then | |
1007 | add it to the list of recipients. */ | |
1008 | ||
1009 | if (recipient_domain == 0) | |
1010 | { | |
1011 | if (allow_unqualified_recipient) | |
1012 | { | |
1013 | DEBUG(D_receive) debug_printf("unqualified address %s accepted\n", | |
1014 | recipient); | |
1015 | recipient = rewrite_address_qualify(recipient, TRUE); | |
1016 | } | |
1017 | /* The function moan_smtp_batch() does not return. */ | |
1018 | else moan_smtp_batch(cmd_buffer, "501 recipient address must contain " | |
1019 | "a domain"); | |
1020 | } | |
1021 | receive_add_recipient(recipient, -1); | |
1022 | break; | |
1023 | ||
1024 | ||
1025 | /* The DATA command is legal only if it follows successful MAIL FROM | |
1026 | and RCPT TO commands. This function is complete when a valid DATA | |
1027 | command is encountered. */ | |
1028 | ||
1029 | case DATA_CMD: | |
1030 | if (sender_address == NULL || recipients_count <= 0) | |
1031 | { | |
1032 | /* The function moan_smtp_batch() does not return. */ | |
1033 | if (sender_address == NULL) | |
1034 | moan_smtp_batch(cmd_buffer, | |
1035 | "503 MAIL FROM:<sender> command must precede DATA"); | |
1036 | else | |
1037 | moan_smtp_batch(cmd_buffer, | |
1038 | "503 RCPT TO:<recipient> must precede DATA"); | |
1039 | } | |
1040 | else | |
1041 | { | |
1042 | done = 3; /* DATA successfully achieved */ | |
1043 | message_ended = END_NOTENDED; /* Indicate in middle of message */ | |
1044 | } | |
1045 | break; | |
1046 | ||
1047 | ||
1048 | /* The VRFY, EXPN, HELP, ETRN, and NOOP commands are ignored. */ | |
1049 | ||
1050 | case VRFY_CMD: | |
1051 | case EXPN_CMD: | |
1052 | case HELP_CMD: | |
1053 | case NOOP_CMD: | |
1054 | case ETRN_CMD: | |
1055 | bsmtp_transaction_linecount = receive_linecount; | |
1056 | break; | |
1057 | ||
1058 | ||
1059 | case EOF_CMD: | |
1060 | case QUIT_CMD: | |
1061 | done = 2; | |
1062 | break; | |
1063 | ||
1064 | ||
1065 | case BADARG_CMD: | |
1066 | /* The function moan_smtp_batch() does not return. */ | |
1067 | moan_smtp_batch(cmd_buffer, "501 Unexpected argument data"); | |
1068 | break; | |
1069 | ||
1070 | ||
1071 | case BADCHAR_CMD: | |
1072 | /* The function moan_smtp_batch() does not return. */ | |
1073 | moan_smtp_batch(cmd_buffer, "501 Unexpected NULL in SMTP command"); | |
1074 | break; | |
1075 | ||
1076 | ||
1077 | default: | |
1078 | /* The function moan_smtp_batch() does not return. */ | |
1079 | moan_smtp_batch(cmd_buffer, "500 Command unrecognized"); | |
1080 | break; | |
1081 | } | |
1082 | } | |
1083 | ||
1084 | return done - 2; /* Convert yield values */ | |
1085 | } | |
1086 | ||
1087 | ||
1088 | ||
1089 | ||
1090 | /************************************************* | |
1091 | * Start an SMTP session * | |
1092 | *************************************************/ | |
1093 | ||
1094 | /* This function is called at the start of an SMTP session. Thereafter, | |
1095 | smtp_setup_msg() is called to initiate each separate message. This | |
1096 | function does host-specific testing, and outputs the banner line. | |
1097 | ||
1098 | Arguments: none | |
1099 | Returns: FALSE if the session can not continue; something has | |
1100 | gone wrong, or the connection to the host is blocked | |
1101 | */ | |
1102 | ||
1103 | BOOL | |
1104 | smtp_start_session(void) | |
1105 | { | |
1106 | int size = 256; | |
1107 | int i, ptr; | |
1108 | uschar *p, *s, *ss; | |
1109 | ||
1110 | helo_seen = esmtp = helo_accept_junk = FALSE; | |
1111 | count_nonmail = TRUE_UNSET; | |
1112 | synprot_error_count = unknown_command_count = nonmail_command_count = 0; | |
1113 | smtp_delay_mail = smtp_rlm_base; | |
1114 | auth_advertised = FALSE; | |
1115 | pipelining_advertised = FALSE; | |
1116 | sync_cmd_limit = NON_SYNC_CMD_NON_PIPELINING; | |
1117 | ||
1118 | memset(sender_host_cache, 0, sizeof(sender_host_cache)); | |
1119 | ||
1120 | sender_host_authenticated = NULL; | |
1121 | authenticated_by = NULL; | |
1122 | ||
1123 | #ifdef SUPPORT_TLS | |
1124 | tls_cipher = tls_peerdn = NULL; | |
1125 | tls_advertised = FALSE; | |
1126 | #endif | |
1127 | ||
1128 | /* Reset ACL connection variables */ | |
1129 | ||
1130 | for (i = 0; i < ACL_C_MAX; i++) acl_var[i] = NULL; | |
1131 | ||
1132 | cmd_buffer = (uschar *)malloc(cmd_buffer_size + 1); /* allow for trailing 0 */ | |
1133 | if (cmd_buffer == NULL) | |
1134 | log_write(0, LOG_MAIN|LOG_PANIC_DIE, | |
1135 | "malloc() failed for SMTP command buffer"); | |
1136 | ||
1137 | /* For batched input, the protocol setting can be overridden from the | |
1138 | command line by a trusted caller. */ | |
1139 | ||
1140 | if (smtp_batched_input) | |
1141 | { | |
1142 | if (received_protocol == NULL) received_protocol = US"local-bsmtp"; | |
1143 | } | |
1144 | ||
1145 | /* For non-batched SMTP input, the protocol setting is forced here. It will be | |
1146 | reset later if any of EHLO/AUTH/STARTTLS are received. */ | |
1147 | ||
1148 | else | |
1149 | received_protocol = | |
1150 | protocols[pnormal] + ((sender_host_address != NULL)? pnlocal : 0); | |
1151 | ||
1152 | /* Set up the buffer for inputting using direct read() calls, and arrange to | |
1153 | call the local functions instead of the standard C ones. */ | |
1154 | ||
1155 | smtp_inbuffer = (uschar *)malloc(in_buffer_size); | |
1156 | if (smtp_inbuffer == NULL) | |
1157 | log_write(0, LOG_MAIN|LOG_PANIC_DIE, "malloc() failed for SMTP input buffer"); | |
1158 | receive_getc = smtp_getc; | |
1159 | receive_ungetc = smtp_ungetc; | |
1160 | receive_feof = smtp_feof; | |
1161 | receive_ferror = smtp_ferror; | |
1162 | smtp_inptr = smtp_inend = smtp_inbuffer; | |
1163 | smtp_had_eof = smtp_had_error = 0; | |
1164 | ||
1165 | /* Set up the message size limit; this may be host-specific */ | |
1166 | ||
1167 | thismessage_size_limit = expand_string_integer(message_size_limit); | |
1168 | if (thismessage_size_limit < 0) | |
1169 | { | |
1170 | if (thismessage_size_limit == -1) | |
1171 | log_write(0, LOG_MAIN|LOG_PANIC, "unable to expand message_size_limit: " | |
1172 | "%s", expand_string_message); | |
1173 | else | |
1174 | log_write(0, LOG_MAIN|LOG_PANIC, "invalid message_size_limit: " | |
1175 | "%s", expand_string_message); | |
1176 | smtp_closedown(US"Temporary local problem - please try later"); | |
1177 | return FALSE; | |
1178 | } | |
1179 | ||
1180 | /* When a message is input locally via the -bs or -bS options, sender_host_ | |
1181 | unknown is set unless -oMa was used to force an IP address, in which case it | |
1182 | is checked like a real remote connection. When -bs is used from inetd, this | |
1183 | flag is not set, causing the sending host to be checked. The code that deals | |
1184 | with IP source routing (if configured) is never required for -bs or -bS and | |
1185 | the flag sender_host_notsocket is used to suppress it. | |
1186 | ||
1187 | If smtp_accept_max and smtp_accept_reserve are set, keep some connections in | |
1188 | reserve for certain hosts and/or networks. */ | |
1189 | ||
1190 | if (!sender_host_unknown) | |
1191 | { | |
1192 | int rc; | |
1193 | BOOL reserved_host = FALSE; | |
1194 | ||
1195 | /* Look up IP options (source routing info) on the socket if this is not an | |
1196 | -oMa "host", and if any are found, log them and drop the connection. | |
1197 | ||
1198 | Linux (and others now, see below) is different to everyone else, so there | |
1199 | has to be some conditional compilation here. Versions of Linux before 2.1.15 | |
1200 | used a structure whose name was "options". Somebody finally realized that | |
1201 | this name was silly, and it got changed to "ip_options". I use the | |
1202 | newer name here, but there is a fudge in the script that sets up os.h | |
1203 | to define a macro in older Linux systems. | |
1204 | ||
1205 | Sigh. Linux is a fast-moving target. Another generation of Linux uses | |
1206 | glibc 2, which has chosen ip_opts for the structure name. This is now | |
1207 | really a glibc thing rather than a Linux thing, so the condition name | |
1208 | has been changed to reflect this. It is relevant also to GNU/Hurd. | |
1209 | ||
1210 | Mac OS 10.x (Darwin) is like the later glibc versions, but without the | |
1211 | setting of the __GLIBC__ macro, so we can't detect it automatically. There's | |
1212 | a special macro defined in the os.h file. | |
1213 | ||
1214 | Some DGUX versions on older hardware appear not to support IP options at | |
1215 | all, so there is now a general macro which can be set to cut out this | |
1216 | support altogether. | |
1217 | ||
1218 | How to do this properly in IPv6 is not yet known. */ | |
1219 | ||
1220 | #if !HAVE_IPV6 && !defined(NO_IP_OPTIONS) | |
1221 | ||
1222 | #ifdef GLIBC_IP_OPTIONS | |
1223 | #if (!defined __GLIBC__) || (__GLIBC__ < 2) | |
1224 | #define OPTSTYLE 1 | |
1225 | #else | |
1226 | #define OPTSTYLE 2 | |
1227 | #endif | |
1228 | #elif defined DARWIN_IP_OPTIONS | |
1229 | #define OPTSTYLE 2 | |
1230 | #else | |
1231 | #define OPTSTYLE 3 | |
1232 | #endif | |
1233 | ||
1234 | if (!host_checking && !sender_host_notsocket) | |
1235 | { | |
1236 | #if OPTSTYLE == 1 | |
1237 | SOCKLEN_T optlen = sizeof(struct ip_options) + MAX_IPOPTLEN; | |
1238 | struct ip_options *ipopt = store_get(optlen); | |
1239 | #elif OPTSTYLE == 2 | |
1240 | struct ip_opts ipoptblock; | |
1241 | struct ip_opts *ipopt = &ipoptblock; | |
1242 | SOCKLEN_T optlen = sizeof(ipoptblock); | |
1243 | #else | |
1244 | struct ipoption ipoptblock; | |
1245 | struct ipoption *ipopt = &ipoptblock; | |
1246 | SOCKLEN_T optlen = sizeof(ipoptblock); | |
1247 | #endif | |
1248 | ||
1249 | /* Occasional genuine failures of getsockopt() have been seen - for | |
1250 | example, "reset by peer". Therefore, just log and give up on this | |
1251 | call, unless the error is ENOPROTOOPT. This error is given by systems | |
1252 | that have the interfaces but not the mechanism - e.g. GNU/Hurd at the time | |
1253 | of writing. So for that error, carry on - we just can't do an IP options | |
1254 | check. */ | |
1255 | ||
1256 | DEBUG(D_receive) debug_printf("checking for IP options\n"); | |
1257 | ||
1258 | if (getsockopt(fileno(smtp_out), IPPROTO_IP, IP_OPTIONS, (uschar *)(ipopt), | |
1259 | &optlen) < 0) | |
1260 | { | |
1261 | if (errno != ENOPROTOOPT) | |
1262 | { | |
1263 | log_write(0, LOG_MAIN, "getsockopt() failed from %s: %s", | |
1264 | host_and_ident(FALSE), strerror(errno)); | |
1265 | smtp_printf("451 SMTP service not available\r\n"); | |
1266 | return FALSE; | |
1267 | } | |
1268 | } | |
1269 | ||
1270 | /* Deal with any IP options that are set. On the systems I have looked at, | |
1271 | the value of MAX_IPOPTLEN has been 40, meaning that there should never be | |
1272 | more logging data than will fit in big_buffer. Nevertheless, after somebody | |
1273 | questioned this code, I've added in some paranoid checking. */ | |
1274 | ||
1275 | else if (optlen > 0) | |
1276 | { | |
1277 | uschar *p = big_buffer; | |
1278 | uschar *pend = big_buffer + big_buffer_size; | |
1279 | uschar *opt, *adptr; | |
1280 | int optcount; | |
1281 | struct in_addr addr; | |
1282 | ||
1283 | #if OPTSTYLE == 1 | |
1284 | uschar *optstart = (uschar *)(ipopt->__data); | |
1285 | #elif OPTSTYLE == 2 | |
1286 | uschar *optstart = (uschar *)(ipopt->ip_opts); | |
1287 | #else | |
1288 | uschar *optstart = (uschar *)(ipopt->ipopt_list); | |
1289 | #endif | |
1290 | ||
1291 | DEBUG(D_receive) debug_printf("IP options exist\n"); | |
1292 | ||
1293 | Ustrcpy(p, "IP options on incoming call:"); | |
1294 | p += Ustrlen(p); | |
1295 | ||
1296 | for (opt = optstart; opt != NULL && | |
1297 | opt < (uschar *)(ipopt) + optlen;) | |
1298 | { | |
1299 | switch (*opt) | |
1300 | { | |
1301 | case IPOPT_EOL: | |
1302 | opt = NULL; | |
1303 | break; | |
1304 | ||
1305 | case IPOPT_NOP: | |
1306 | opt++; | |
1307 | break; | |
1308 | ||
1309 | case IPOPT_SSRR: | |
1310 | case IPOPT_LSRR: | |
1311 | if (!string_format(p, pend-p, " %s [@%s", | |
1312 | (*opt == IPOPT_SSRR)? "SSRR" : "LSRR", | |
1313 | #if OPTSTYLE == 1 | |
1314 | inet_ntoa(*((struct in_addr *)(&(ipopt->faddr)))))) | |
1315 | #elif OPTSTYLE == 2 | |
1316 | inet_ntoa(ipopt->ip_dst))) | |
1317 | #else | |
1318 | inet_ntoa(ipopt->ipopt_dst))) | |
1319 | #endif | |
1320 | { | |
1321 | opt = NULL; | |
1322 | break; | |
1323 | } | |
1324 | ||
1325 | p += Ustrlen(p); | |
1326 | optcount = (opt[1] - 3) / sizeof(struct in_addr); | |
1327 | adptr = opt + 3; | |
1328 | while (optcount-- > 0) | |
1329 | { | |
1330 | memcpy(&addr, adptr, sizeof(addr)); | |
1331 | if (!string_format(p, pend - p - 1, "%s%s", | |
1332 | (optcount == 0)? ":" : "@", inet_ntoa(addr))) | |
1333 | { | |
1334 | opt = NULL; | |
1335 | break; | |
1336 | } | |
1337 | p += Ustrlen(p); | |
1338 | adptr += sizeof(struct in_addr); | |
1339 | } | |
1340 | *p++ = ']'; | |
1341 | opt += opt[1]; | |
1342 | break; | |
1343 | ||
1344 | default: | |
1345 | { | |
1346 | int i; | |
1347 | if (pend - p < 4 + 3*opt[1]) { opt = NULL; break; } | |
1348 | Ustrcat(p, "[ "); | |
1349 | p += 2; | |
1350 | for (i = 0; i < opt[1]; i++) | |
1351 | { | |
1352 | sprintf(CS p, "%2.2x ", opt[i]); | |
1353 | p += 3; | |
1354 | } | |
1355 | *p++ = ']'; | |
1356 | } | |
1357 | opt += opt[1]; | |
1358 | break; | |
1359 | } | |
1360 | } | |
1361 | ||
1362 | *p = 0; | |
1363 | log_write(0, LOG_MAIN, "%s", big_buffer); | |
1364 | ||
1365 | /* Refuse any call with IP options. This is what tcpwrappers 7.5 does. */ | |
1366 | ||
1367 | log_write(0, LOG_MAIN|LOG_REJECT, | |
1368 | "connection from %s refused (IP options)", host_and_ident(FALSE)); | |
1369 | ||
1370 | smtp_printf("554 SMTP service not available\r\n"); | |
1371 | return FALSE; | |
1372 | } | |
1373 | ||
1374 | /* Length of options = 0 => there are no options */ | |
1375 | ||
1376 | else DEBUG(D_receive) debug_printf("no IP options found\n"); | |
1377 | } | |
1378 | #endif /* HAVE_IPV6 && !defined(NO_IP_OPTIONS) */ | |
1379 | ||
1380 | /* Set keep-alive in socket options. The option is on by default. This | |
1381 | setting is an attempt to get rid of some hanging connections that stick in | |
1382 | read() when the remote end (usually a dialup) goes away. */ | |
1383 | ||
1384 | if (smtp_accept_keepalive && !sender_host_notsocket) | |
1385 | ip_keepalive(fileno(smtp_out), sender_host_address, FALSE); | |
1386 | ||
1387 | /* If the current host matches host_lookup, set the name by doing a | |
1388 | reverse lookup. On failure, sender_host_name will be NULL and | |
1389 | host_lookup_failed will be TRUE. This may or may not be serious - optional | |
1390 | checks later. */ | |
1391 | ||
1392 | if (verify_check_host(&host_lookup) == OK) | |
1393 | { | |
1394 | (void)host_name_lookup(); | |
1395 | host_build_sender_fullhost(); | |
1396 | } | |
1397 | ||
1398 | /* Delay this until we have the full name, if it is looked up. */ | |
1399 | ||
1400 | set_process_info("handling incoming connection from %s", | |
1401 | host_and_ident(FALSE)); | |
1402 | ||
1403 | /* Start up TLS if tls_on_connect is set. This is for supporting the legacy | |
1404 | smtps port for use with older style SSL MTAs. */ | |
1405 | ||
1406 | #ifdef SUPPORT_TLS | |
1407 | if (tls_on_connect && tls_server_start(tls_require_ciphers) != OK) | |
1408 | return FALSE; | |
1409 | #endif | |
1410 | ||
1411 | /* Test for explicit connection rejection */ | |
1412 | ||
1413 | if (verify_check_host(&host_reject_connection) == OK) | |
1414 | { | |
1415 | log_write(L_connection_reject, LOG_MAIN|LOG_REJECT, "refused connection " | |
1416 | "from %s (host_reject_connection)", host_and_ident(FALSE)); | |
1417 | smtp_printf("554 SMTP service not available\r\n"); | |
1418 | return FALSE; | |
1419 | } | |
1420 | ||
1421 | /* Test with TCP Wrappers if so configured */ | |
1422 | ||
1423 | #ifdef USE_TCP_WRAPPERS | |
1424 | if (!hosts_ctl("exim", | |
1425 | (sender_host_name == NULL)? STRING_UNKNOWN : CS sender_host_name, | |
1426 | (sender_host_address == NULL)? STRING_UNKNOWN : CS sender_host_address, | |
1427 | (sender_ident == NULL)? STRING_UNKNOWN : CS sender_ident)) | |
1428 | { | |
1429 | HDEBUG(D_receive) debug_printf("tcp wrappers rejection\n"); | |
1430 | log_write(L_connection_reject, | |
1431 | LOG_MAIN|LOG_REJECT, "refused connection from %s " | |
1432 | "(tcp wrappers)", host_and_ident(FALSE)); | |
1433 | smtp_printf("554 SMTP service not available\r\n"); | |
1434 | return FALSE; | |
1435 | } | |
1436 | #endif | |
1437 | ||
1438 | /* Check for reserved slots. Note that the count value doesn't include | |
1439 | this process, as it gets upped in the parent process. */ | |
1440 | ||
1441 | if (smtp_accept_max > 0 && | |
1442 | smtp_accept_count + 1 > smtp_accept_max - smtp_accept_reserve) | |
1443 | { | |
1444 | if ((rc = verify_check_host(&smtp_reserve_hosts)) != OK) | |
1445 | { | |
1446 | log_write(L_connection_reject, | |
1447 | LOG_MAIN, "temporarily refused connection from %s: not in " | |
1448 | "reserve list: connected=%d max=%d reserve=%d%s", | |
1449 | host_and_ident(FALSE), smtp_accept_count, smtp_accept_max, | |
1450 | smtp_accept_reserve, (rc == DEFER)? " (lookup deferred)" : ""); | |
1451 | smtp_printf("421 %s: Too many concurrent SMTP connections; " | |
1452 | "please try again later\r\n", smtp_active_hostname); | |
1453 | return FALSE; | |
1454 | } | |
1455 | reserved_host = TRUE; | |
1456 | } | |
1457 | ||
1458 | /* If a load level above which only messages from reserved hosts are | |
1459 | accepted is set, check the load. For incoming calls via the daemon, the | |
1460 | check is done in the superior process if there are no reserved hosts, to | |
1461 | save a fork. In all cases, the load average will already be available | |
1462 | in a global variable at this point. */ | |
1463 | ||
1464 | if (smtp_load_reserve >= 0 && | |
1465 | load_average > smtp_load_reserve && | |
1466 | !reserved_host && | |
1467 | verify_check_host(&smtp_reserve_hosts) != OK) | |
1468 | { | |
1469 | log_write(L_connection_reject, | |
1470 | LOG_MAIN, "temporarily refused connection from %s: not in " | |
1471 | "reserve list and load average = %.2f", host_and_ident(FALSE), | |
1472 | (double)load_average/1000.0); | |
1473 | smtp_printf("421 %s: Too much load; please try again later\r\n", | |
1474 | smtp_active_hostname); | |
1475 | return FALSE; | |
1476 | } | |
1477 | ||
1478 | /* Determine whether unqualified senders or recipients are permitted | |
1479 | for this host. Unfortunately, we have to do this every time, in order to | |
1480 | set the flags so that they can be inspected when considering qualifying | |
1481 | addresses in the headers. For a site that permits no qualification, this | |
1482 | won't take long, however. */ | |
1483 | ||
1484 | allow_unqualified_sender = | |
1485 | verify_check_host(&sender_unqualified_hosts) == OK; | |
1486 | ||
1487 | allow_unqualified_recipient = | |
1488 | verify_check_host(&recipient_unqualified_hosts) == OK; | |
1489 | ||
1490 | /* Determine whether HELO/EHLO is required for this host. The requirement | |
1491 | can be hard or soft. */ | |
1492 | ||
1493 | helo_required = verify_check_host(&helo_verify_hosts) == OK; | |
1494 | if (!helo_required) | |
1495 | helo_verify = verify_check_host(&helo_try_verify_hosts) == OK; | |
1496 | ||
1497 | /* Determine whether this hosts is permitted to send syntactic junk | |
1498 | after a HELO or EHLO command. */ | |
1499 | ||
1500 | helo_accept_junk = verify_check_host(&helo_accept_junk_hosts) == OK; | |
1501 | } | |
1502 | ||
1503 | /* For batch SMTP input we are now done. */ | |
1504 | ||
1505 | if (smtp_batched_input) return TRUE; | |
1506 | ||
1507 | /* Run the ACL if it exists */ | |
1508 | ||
1509 | if (acl_smtp_connect != NULL) | |
1510 | { | |
1511 | int rc; | |
1512 | uschar *user_msg, *log_msg; | |
1513 | smtp_data = US"in \"connect\" ACL"; /* For logged failure message */ | |
1514 | rc = acl_check(ACL_WHERE_CONNECT, US"", acl_smtp_connect, &user_msg, | |
1515 | &log_msg); | |
1516 | if (rc != OK) | |
1517 | { | |
1518 | (void)smtp_handle_acl_fail(ACL_WHERE_CONNECT, rc, user_msg, log_msg); | |
1519 | return FALSE; | |
1520 | } | |
1521 | } | |
1522 | ||
1523 | /* Output the initial message for a two-way SMTP connection. It may contain | |
1524 | newlines, which then cause a multi-line response to be given. */ | |
1525 | ||
1526 | s = expand_string(smtp_banner); | |
1527 | if (s == NULL) | |
1528 | log_write(0, LOG_MAIN|LOG_PANIC_DIE, "Expansion of \"%s\" (smtp_banner) " | |
1529 | "failed: %s", smtp_banner, expand_string_message); | |
1530 | ||
1531 | /* Remove any terminating newlines; might as well remove trailing space too */ | |
1532 | ||
1533 | p = s + Ustrlen(s); | |
1534 | while (p > s && isspace(p[-1])) p--; | |
1535 | *p = 0; | |
1536 | ||
1537 | /* It seems that CC:Mail is braindead, and assumes that the greeting message | |
1538 | is all contained in a single IP packet. The original code wrote out the | |
1539 | greeting using several calls to fprint/fputc, and on busy servers this could | |
1540 | cause it to be split over more than one packet - which caused CC:Mail to fall | |
1541 | over when it got the second part of the greeting after sending its first | |
1542 | command. Sigh. To try to avoid this, build the complete greeting message | |
1543 | first, and output it in one fell swoop. This gives a better chance of it | |
1544 | ending up as a single packet. */ | |
1545 | ||
1546 | ss = store_get(size); | |
1547 | ptr = 0; | |
1548 | ||
1549 | p = s; | |
1550 | do /* At least once, in case we have an empty string */ | |
1551 | { | |
1552 | int len; | |
1553 | uschar *linebreak = Ustrchr(p, '\n'); | |
1554 | if (linebreak == NULL) | |
1555 | { | |
1556 | len = Ustrlen(p); | |
1557 | ss = string_cat(ss, &size, &ptr, US"220 ", 4); | |
1558 | } | |
1559 | else | |
1560 | { | |
1561 | len = linebreak - p; | |
1562 | ss = string_cat(ss, &size, &ptr, US"220-", 4); | |
1563 | } | |
1564 | ss = string_cat(ss, &size, &ptr, p, len); | |
1565 | ss = string_cat(ss, &size, &ptr, US"\r\n", 2); | |
1566 | p += len; | |
1567 | if (linebreak != NULL) p++; | |
1568 | } | |
1569 | while (*p != 0); | |
1570 | ||
1571 | ss[ptr] = 0; /* string_cat leaves room for this */ | |
1572 | ||
1573 | /* Before we write the banner, check that there is no input pending, unless | |
1574 | this synchronisation check is disabled. */ | |
1575 | ||
1576 | if (smtp_enforce_sync && sender_host_address != NULL && !sender_host_notsocket) | |
1577 | { | |
1578 | fd_set fds; | |
1579 | struct timeval tzero; | |
1580 | tzero.tv_sec = 0; | |
1581 | tzero.tv_usec = 0; | |
1582 | FD_ZERO(&fds); | |
1583 | FD_SET(fileno(smtp_in), &fds); | |
1584 | if (select(fileno(smtp_in) + 1, (SELECT_ARG2_TYPE *)&fds, NULL, NULL, | |
1585 | &tzero) > 0) | |
1586 | { | |
1587 | log_write(0, LOG_MAIN|LOG_REJECT, "SMTP protocol violation: " | |
1588 | "synchronization error (input sent without waiting for greeting): " | |
1589 | "rejected connection from %s", host_and_ident(TRUE)); | |
1590 | smtp_printf("554 SMTP synchronization error\r\n"); | |
1591 | return FALSE; | |
1592 | } | |
1593 | } | |
1594 | ||
1595 | /* Now output the banner */ | |
1596 | ||
1597 | smtp_printf("%s", ss); | |
1598 | return TRUE; | |
1599 | } | |
1600 | ||
1601 | ||
1602 | ||
1603 | ||
1604 | ||
1605 | /************************************************* | |
1606 | * Handle SMTP syntax and protocol errors * | |
1607 | *************************************************/ | |
1608 | ||
1609 | /* Write to the log for SMTP syntax errors in incoming commands, if configured | |
1610 | to do so. Then transmit the error response. The return value depends on the | |
1611 | number of syntax and protocol errors in this SMTP session. | |
1612 | ||
1613 | Arguments: | |
1614 | type error type, given as a log flag bit | |
1615 | code response code; <= 0 means don't send a response | |
1616 | data data to reflect in the response (can be NULL) | |
1617 | errmess the error message | |
1618 | ||
1619 | Returns: -1 limit of syntax/protocol errors NOT exceeded | |
1620 | +1 limit of syntax/protocol errors IS exceeded | |
1621 | ||
1622 | These values fit in with the values of the "done" variable in the main | |
1623 | processing loop in smtp_setup_msg(). */ | |
1624 | ||
1625 | static int | |
1626 | synprot_error(int type, int code, uschar *data, uschar *errmess) | |
1627 | { | |
1628 | int yield = -1; | |
1629 | ||
1630 | log_write(type, LOG_MAIN, "SMTP %s error in \"%s\" %s %s", | |
1631 | (type == L_smtp_syntax_error)? "syntax" : "protocol", | |
1632 | string_printing(cmd_buffer), host_and_ident(TRUE), errmess); | |
1633 | ||
1634 | if (++synprot_error_count > smtp_max_synprot_errors) | |
1635 | { | |
1636 | yield = 1; | |
1637 | log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many " | |
1638 | "syntax or protocol errors (last command was \"%s\")", | |
1639 | host_and_ident(FALSE), cmd_buffer); | |
1640 | } | |
1641 | ||
1642 | if (code > 0) | |
1643 | { | |
1644 | smtp_printf("%d%c%s%s%s\r\n", code, (yield == 1)? '-' : ' ', | |
1645 | (data == NULL)? US"" : data, (data == NULL)? US"" : US": ", errmess); | |
1646 | if (yield == 1) | |
1647 | smtp_printf("%d Too many syntax or protocol errors\r\n", code); | |
1648 | } | |
1649 | ||
1650 | return yield; | |
1651 | } | |
1652 | ||
1653 | ||
1654 | ||
1655 | ||
1656 | /************************************************* | |
1657 | * Log incomplete transactions * | |
1658 | *************************************************/ | |
1659 | ||
1660 | /* This function is called after a transaction has been aborted by RSET, QUIT, | |
1661 | connection drops or other errors. It logs the envelope information received | |
1662 | so far in order to preserve address verification attempts. | |
1663 | ||
1664 | Argument: string to indicate what aborted the transaction | |
1665 | Returns: nothing | |
1666 | */ | |
1667 | ||
1668 | static void | |
1669 | incomplete_transaction_log(uschar *what) | |
1670 | { | |
1671 | if (sender_address == NULL || /* No transaction in progress */ | |
1672 | (log_write_selector & L_smtp_incomplete_transaction) == 0 /* Not logging */ | |
1673 | ) return; | |
1674 | ||
1675 | /* Build list of recipients for logging */ | |
1676 | ||
1677 | if (recipients_count > 0) | |
1678 | { | |
1679 | int i; | |
1680 | raw_recipients = store_get(recipients_count * sizeof(uschar *)); | |
1681 | for (i = 0; i < recipients_count; i++) | |
1682 | raw_recipients[i] = recipients_list[i].address; | |
1683 | raw_recipients_count = recipients_count; | |
1684 | } | |
1685 | ||
1686 | log_write(L_smtp_incomplete_transaction, LOG_MAIN|LOG_SENDER|LOG_RECIPIENTS, | |
1687 | "%s incomplete transaction (%s)", host_and_ident(TRUE), what); | |
1688 | } | |
1689 | ||
1690 | ||
1691 | ||
1692 | ||
1693 | /************************************************* | |
1694 | * Send SMTP response, possibly multiline * | |
1695 | *************************************************/ | |
1696 | ||
1697 | /* There are, it seems, broken clients out there that cannot handle multiline | |
1698 | responses. If no_multiline_responses is TRUE (it can be set from an ACL), we | |
1699 | output nothing for non-final calls, and only the first line for anything else. | |
1700 | ||
1701 | Arguments: | |
1702 | code SMTP code | |
1703 | final FALSE if the last line isn't the final line | |
1704 | msg message text, possibly containing newlines | |
1705 | ||
1706 | Returns: nothing | |
1707 | */ | |
1708 | ||
1709 | void | |
1710 | smtp_respond(int code, BOOL final, uschar *msg) | |
1711 | { | |
1712 | if (!final && no_multiline_responses) return; | |
1713 | ||
1714 | for (;;) | |
1715 | { | |
1716 | uschar *nl = Ustrchr(msg, '\n'); | |
1717 | if (nl == NULL) | |
1718 | { | |
1719 | smtp_printf("%d%c%s\r\n", code, final? ' ':'-', msg); | |
1720 | return; | |
1721 | } | |
1722 | else if (nl[1] == 0 || no_multiline_responses) | |
1723 | { | |
1724 | smtp_printf("%d%c%.*s\r\n", code, final? ' ':'-', (int)(nl - msg), msg); | |
1725 | return; | |
1726 | } | |
1727 | else | |
1728 | { | |
1729 | smtp_printf("%d-%.*s\r\n", code, (int)(nl - msg), msg); | |
1730 | msg = nl + 1; | |
1731 | while (isspace(*msg)) msg++; | |
1732 | } | |
1733 | } | |
1734 | } | |
1735 | ||
1736 | ||
1737 | ||
1738 | ||
1739 | /************************************************* | |
1740 | * Handle an ACL failure * | |
1741 | *************************************************/ | |
1742 | ||
1743 | /* This function is called when acl_check() fails. As well as calls from within | |
1744 | this module, it is called from receive.c for an ACL after DATA. It sorts out | |
1745 | logging the incident, and sets up the error response. A message containing | |
1746 | newlines is turned into a multiline SMTP response, but for logging, only the | |
1747 | first line is used. | |
1748 | ||
1749 | There's a table of the response codes to use in globals.c, along with the table | |
1750 | of names. VFRY is special. Despite RFC1123 it defaults disabled in Exim. | |
1751 | However, discussion in connection with RFC 821bis (aka RFC 2821) has concluded | |
1752 | that the response should be 252 in the disabled state, because there are broken | |
1753 | clients that try VRFY before RCPT. A 5xx response should be given only when the | |
1754 | address is positively known to be undeliverable. Sigh. Also, for ETRN, 458 is | |
1755 | given on refusal, and for AUTH, 503. | |
1756 | ||
1757 | Arguments: | |
1758 | where where the ACL was called from | |
1759 | rc the failure code | |
1760 | user_msg a message that can be included in an SMTP response | |
1761 | log_msg a message for logging | |
1762 | ||
1763 | Returns: 0 in most cases | |
1764 | 2 if the failure code was FAIL_DROP, in which case the | |
1765 | SMTP connection should be dropped (this value fits with the | |
1766 | "done" variable in smtp_setup_msg() below) | |
1767 | */ | |
1768 | ||
1769 | int | |
1770 | smtp_handle_acl_fail(int where, int rc, uschar *user_msg, uschar *log_msg) | |
1771 | { | |
1772 | int code = acl_wherecodes[where]; | |
1773 | BOOL drop = rc == FAIL_DROP; | |
1774 | uschar *lognl; | |
1775 | uschar *sender_info = US""; | |
1776 | uschar *what = (where == ACL_WHERE_PREDATA)? US"DATA" : | |
1777 | (where == ACL_WHERE_DATA)? US"after DATA" : | |
1778 | string_sprintf("%s %s", acl_wherenames[where], smtp_data); | |
1779 | ||
1780 | if (drop) rc = FAIL; | |
1781 | ||
1782 | /* We used to have sender_address here; however, there was a bug that was not | |
1783 | updating sender_address after a rewrite during a verify. When this bug was | |
1784 | fixed, sender_address at this point became the rewritten address. I'm not sure | |
1785 | this is what should be logged, so I've changed to logging the unrewritten | |
1786 | address to retain backward compatibility. */ | |
1787 | ||
1788 | if (where == ACL_WHERE_RCPT || where == ACL_WHERE_DATA) | |
1789 | { | |
1790 | sender_info = string_sprintf("F=<%s> ", (sender_address_unrewritten != NULL)? | |
1791 | sender_address_unrewritten : sender_address); | |
1792 | } | |
1793 | ||
1794 | /* If there's been a sender verification failure with a specific message, and | |
1795 | we have not sent a response about it yet, do so now, as a preliminary line for | |
1796 | failures, but not defers. However, log it in both cases. */ | |
1797 | ||
1798 | if (sender_verified_failed != NULL && | |
1799 | !testflag(sender_verified_failed, af_sverify_told)) | |
1800 | { | |
1801 | setflag(sender_verified_failed, af_sverify_told); | |
1802 | ||
1803 | log_write(0, LOG_MAIN|LOG_REJECT, "%s sender verify %s for <%s>%s", | |
1804 | host_and_ident(TRUE), | |
1805 | ((sender_verified_failed->special_action & 255) == DEFER)? "defer" : "fail", | |
1806 | sender_verified_failed->address, | |
1807 | (sender_verified_failed->message == NULL)? US"" : | |
1808 | string_sprintf(": %s", sender_verified_failed->message)); | |
1809 | ||
1810 | if (rc == FAIL && sender_verified_failed->user_message != NULL) | |
1811 | smtp_respond(code, FALSE, string_sprintf( | |
1812 | testflag(sender_verified_failed, af_verify_pmfail)? | |
1813 | "Postmaster verification failed while checking <%s>\n%s\n" | |
1814 | "Several RFCs state that you are required to have a postmaster\n" | |
1815 | "mailbox for each mail domain. This host does not accept mail\n" | |
1816 | "from domains whose servers reject the postmaster address." | |
1817 | : | |
1818 | testflag(sender_verified_failed, af_verify_nsfail)? | |
1819 | "Callback setup failed while verifying <%s>\n%s\n" | |
1820 | "The initial connection, or a HELO or MAIL FROM:<> command was\n" | |
1821 | "rejected. Refusing MAIL FROM:<> does not help fight spam, disregards\n" | |
1822 | "RFC requirements, and stops you from receiving standard bounce\n" | |
1823 | "messages. This host does not accept mail from domains whose servers\n" | |
1824 | "refuse bounces." | |
1825 | : | |
1826 | "Verification failed for <%s>\n%s", | |
1827 | sender_verified_failed->address, | |
1828 | sender_verified_failed->user_message)); | |
1829 | } | |
1830 | ||
1831 | /* Sort out text for logging */ | |
1832 | ||
1833 | log_msg = (log_msg == NULL)? US"" : string_sprintf(": %s", log_msg); | |
1834 | lognl = Ustrchr(log_msg, '\n'); | |
1835 | if (lognl != NULL) *lognl = 0; | |
1836 | ||
1837 | /* Send permanent failure response to the command, but the code used isn't | |
1838 | always a 5xx one - see comments at the start of this function. If the original | |
1839 | rc was FAIL_DROP we drop the connection and yield 2. */ | |
1840 | ||
1841 | if (rc == FAIL) smtp_respond(code, TRUE, (user_msg == NULL)? | |
1842 | US"Administrative prohibition" : user_msg); | |
1843 | ||
1844 | /* Send temporary failure response to the command. Don't give any details, | |
1845 | unless acl_temp_details is set. This is TRUE for a callout defer, a "defer" | |
1846 | verb, and for a header verify when smtp_return_error_details is set. | |
1847 | ||
1848 | This conditional logic is all somewhat of a mess because of the odd | |
1849 | interactions between temp_details and return_error_details. One day it should | |
1850 | be re-implemented in a tidier fashion. */ | |
1851 | ||
1852 | else | |
1853 | { | |
1854 | if (acl_temp_details && user_msg != NULL) | |
1855 | { | |
1856 | if (smtp_return_error_details && | |
1857 | sender_verified_failed != NULL && | |
1858 | sender_verified_failed->message != NULL) | |
1859 | { | |
1860 | smtp_respond(451, FALSE, sender_verified_failed->message); | |
1861 | } | |
1862 | smtp_respond(451, TRUE, user_msg); | |
1863 | } | |
1864 | else | |
1865 | smtp_printf("451 Temporary local problem - please try later\r\n"); | |
1866 | } | |
1867 | ||
1868 | /* Log the incident. If the connection is not forcibly to be dropped, return 0. | |
1869 | Otherwise, log why it is closing if required and return 2. */ | |
1870 | ||
1871 | log_write(0, LOG_MAIN|LOG_REJECT, "%s %s%srejected %s%s", | |
1872 | host_and_ident(TRUE), | |
1873 | sender_info, (rc == FAIL)? US"" : US"temporarily ", what, log_msg); | |
1874 | ||
1875 | if (!drop) return 0; | |
1876 | ||
1877 | log_write(L_smtp_connection, LOG_MAIN, "%s closed by DROP in ACL", | |
1878 | smtp_get_connection_info()); | |
1879 | return 2; | |
1880 | } | |
1881 | ||
1882 | ||
1883 | ||
1884 | ||
1885 | /************************************************* | |
1886 | * Initialize for SMTP incoming message * | |
1887 | *************************************************/ | |
1888 | ||
1889 | /* This function conducts the initial dialogue at the start of an incoming SMTP | |
1890 | message, and builds a list of recipients. However, if the incoming message | |
1891 | is part of a batch (-bS option) a separate function is called since it would | |
1892 | be messy having tests splattered about all over this function. This function | |
1893 | therefore handles the case where interaction is occurring. The input and output | |
1894 | files are set up in smtp_in and smtp_out. | |
1895 | ||
1896 | The global recipients_list is set to point to a vector of recipient_item | |
1897 | blocks, whose number is given by recipients_count. This is extended by the | |
1898 | receive_add_recipient() function. The global variable sender_address is set to | |
1899 | the sender's address. The yield is +1 if a message has been successfully | |
1900 | started, 0 if a QUIT command was encountered or the connection was refused from | |
1901 | the particular host, or -1 if the connection was lost. | |
1902 | ||
1903 | Argument: none | |
1904 | ||
1905 | Returns: > 0 message successfully started (reached DATA) | |
1906 | = 0 QUIT read or end of file reached or call refused | |
1907 | < 0 lost connection | |
1908 | */ | |
1909 | ||
1910 | int | |
1911 | smtp_setup_msg(void) | |
1912 | { | |
1913 | int done = 0; | |
1914 | BOOL toomany = FALSE; | |
1915 | BOOL discarded = FALSE; | |
1916 | BOOL last_was_rej_mail = FALSE; | |
1917 | BOOL last_was_rcpt = FALSE; | |
1918 | void *reset_point = store_get(0); | |
1919 | ||
1920 | DEBUG(D_receive) debug_printf("smtp_setup_msg entered\n"); | |
1921 | ||
1922 | /* Reset for start of new message. We allow one RSET not to be counted as a | |
1923 | nonmail command, for those MTAs that insist on sending it between every | |
1924 | message. Ditto for EHLO/HELO and for STARTTLS, to allow for going in and out of | |
1925 | TLS between messages (an Exim client may do this if it has messages queued up | |
1926 | for the host). Note: we do NOT reset AUTH at this point. */ | |
1927 | ||
1928 | smtp_reset(reset_point); | |
1929 | message_ended = END_NOTSTARTED; | |
1930 | ||
1931 | cmd_list[CMD_LIST_RSET].is_mail_cmd = TRUE; | |
1932 | cmd_list[CMD_LIST_HELO].is_mail_cmd = TRUE; | |
1933 | cmd_list[CMD_LIST_EHLO].is_mail_cmd = TRUE; | |
1934 | #ifdef SUPPORT_TLS | |
1935 | cmd_list[CMD_LIST_STARTTLS].is_mail_cmd = TRUE; | |
1936 | #endif | |
1937 | ||
1938 | /* Set the local signal handler for SIGTERM - it tries to end off tidily */ | |
1939 | ||
1940 | os_non_restarting_signal(SIGTERM, command_sigterm_handler); | |
1941 | ||
1942 | /* Batched SMTP is handled in a different function. */ | |
1943 | ||
1944 | if (smtp_batched_input) return smtp_setup_batch_msg(); | |
1945 | ||
1946 | /* Deal with SMTP commands. This loop is exited by setting done to a POSITIVE | |
1947 | value. The values are 2 larger than the required yield of the function. */ | |
1948 | ||
1949 | while (done <= 0) | |
1950 | { | |
1951 | uschar **argv; | |
1952 | uschar *etrn_command; | |
1953 | uschar *etrn_serialize_key; | |
1954 | uschar *errmess; | |
1955 | uschar *user_msg, *log_msg; | |
1956 | uschar *recipient = NULL; | |
1957 | uschar *hello = NULL; | |
1958 | uschar *set_id = NULL; | |
1959 | uschar *s, *ss; | |
1960 | BOOL was_rej_mail = FALSE; | |
1961 | BOOL was_rcpt = FALSE; | |
1962 | void (*oldsignal)(int); | |
1963 | pid_t pid; | |
1964 | int start, end, sender_domain, recipient_domain; | |
1965 | int ptr, size, rc; | |
1966 | int c; | |
1967 | auth_instance *au; | |
1968 | ||
1969 | switch(smtp_read_command(TRUE)) | |
1970 | { | |
1971 | /* The AUTH command is not permitted to occur inside a transaction, and may | |
1972 | occur successfully only once per connection, and then only when we've | |
1973 | advertised it. Actually, that isn't quite true. When TLS is started, all | |
1974 | previous information about a connection must be discarded, so a new AUTH is | |
1975 | permitted at that time. | |
1976 | ||
1977 | AUTH is initially labelled as a "nonmail command" so that one occurrence | |
1978 | doesn't get counted. We change the label here so that multiple failing | |
1979 | AUTHS will eventually hit the nonmail threshold. */ | |
1980 | ||
1981 | case AUTH_CMD: | |
1982 | authentication_failed = TRUE; | |
1983 | cmd_list[CMD_LIST_AUTH].is_mail_cmd = FALSE; | |
1984 | ||
1985 | if (!auth_advertised) | |
1986 | { | |
1987 | done = synprot_error(L_smtp_protocol_error, 503, NULL, | |
1988 | US"AUTH command used when not advertised"); | |
1989 | break; | |
1990 | } | |
1991 | if (sender_host_authenticated != NULL) | |
1992 | { | |
1993 | done = synprot_error(L_smtp_protocol_error, 503, NULL, | |
1994 | US"already authenticated"); | |
1995 | break; | |
1996 | } | |
1997 | if (sender_address != NULL) | |
1998 | { | |
1999 | done = synprot_error(L_smtp_protocol_error, 503, NULL, | |
2000 | US"not permitted in mail transaction"); | |
2001 | break; | |
2002 | } | |
2003 | ||
2004 | /* Check the ACL */ | |
2005 | ||
2006 | if (acl_smtp_auth != NULL) | |
2007 | { | |
2008 | rc = acl_check(ACL_WHERE_AUTH, smtp_data, acl_smtp_auth, &user_msg, | |
2009 | &log_msg); | |
2010 | if (rc != OK) | |
2011 | { | |
2012 | done = smtp_handle_acl_fail(ACL_WHERE_AUTH, rc, user_msg, log_msg); | |
2013 | break; | |
2014 | } | |
2015 | } | |
2016 | ||
2017 | /* Find the name of the requested authentication mechanism. */ | |
2018 | ||
2019 | s = smtp_data; | |
2020 | while ((c = *smtp_data) != 0 && !isspace(c)) | |
2021 | { | |
2022 | if (!isalnum(c) && c != '-' && c != '_') | |
2023 | { | |
2024 | done = synprot_error(L_smtp_syntax_error, 501, NULL, | |
2025 | US"invalid character in authentication mechanism name"); | |
2026 | goto COMMAND_LOOP; | |
2027 | } | |
2028 | smtp_data++; | |
2029 | } | |
2030 | ||
2031 | /* If not at the end of the line, we must be at white space. Terminate the | |
2032 | name and move the pointer on to any data that may be present. */ | |
2033 | ||
2034 | if (*smtp_data != 0) | |
2035 | { | |
2036 | *smtp_data++ = 0; | |
2037 | while (isspace(*smtp_data)) smtp_data++; | |
2038 | } | |
2039 | ||
2040 | /* Search for an authentication mechanism which is configured for use | |
2041 | as a server and which has been advertised. */ | |
2042 | ||
2043 | for (au = auths; au != NULL; au = au->next) | |
2044 | { | |
2045 | if (strcmpic(s, au->public_name) == 0 && au->server && | |
2046 | au->advertised) break; | |
2047 | } | |
2048 | ||
2049 | if (au == NULL) | |
2050 | { | |
2051 | done = synprot_error(L_smtp_protocol_error, 504, NULL, | |
2052 | string_sprintf("%s authentication mechanism not supported", s)); | |
2053 | break; | |
2054 | } | |
2055 | ||
2056 | /* Run the checking code, passing the remainder of the command | |
2057 | line as data. Initialize $0 empty. The authenticator may set up | |
2058 | other numeric variables. Afterwards, have a go at expanding the set_id | |
2059 | string, even if authentication failed - for bad passwords it can be useful | |
2060 | to log the userid. On success, require set_id to expand and exist, and | |
2061 | put it in authenticated_id. Save this in permanent store, as the working | |
2062 | store gets reset at HELO, RSET, etc. */ | |
2063 | ||
2064 | expand_nmax = 0; | |
2065 | expand_nlength[0] = 0; /* $0 contains nothing */ | |
2066 | ||
2067 | c = (au->info->servercode)(au, smtp_data); | |
2068 | if (au->set_id != NULL) set_id = expand_string(au->set_id); | |
2069 | expand_nmax = -1; /* Reset numeric variables */ | |
2070 | ||
2071 | /* For the non-OK cases, set up additional logging data if set_id | |
2072 | is not empty. */ | |
2073 | ||
2074 | if (c != OK) | |
2075 | { | |
2076 | if (set_id != NULL && *set_id != 0) | |
2077 | set_id = string_sprintf(" (set_id=%s)", set_id); | |
2078 | else set_id = US""; | |
2079 | } | |
2080 | ||
2081 | /* Switch on the result */ | |
2082 | ||
2083 | switch(c) | |
2084 | { | |
2085 | case OK: | |
2086 | if (au->set_id == NULL || set_id != NULL) /* Complete success */ | |
2087 | { | |
2088 | if (set_id != NULL) authenticated_id = string_copy_malloc(set_id); | |
2089 | sender_host_authenticated = au->name; | |
2090 | authentication_failed = FALSE; | |
2091 | received_protocol = | |
2092 | protocols[pextend + pauthed + ((tls_active >= 0)? pcrpted:0)] + | |
2093 | ((sender_host_address != NULL)? pnlocal : 0); | |
2094 | s = ss = US"235 Authentication succeeded"; | |
2095 | authenticated_by = au; | |
2096 | break; | |
2097 | } | |
2098 | ||
2099 | /* Authentication succeeded, but we failed to expand the set_id string. | |
2100 | Treat this as a temporary error. */ | |
2101 | ||
2102 | auth_defer_msg = expand_string_message; | |
2103 | /* Fall through */ | |
2104 | ||
2105 | case DEFER: | |
2106 | s = string_sprintf("435 Unable to authenticate at present%s", | |
2107 | auth_defer_user_msg); | |
2108 | ss = string_sprintf("435 Unable to authenticate at present%s: %s", | |
2109 | set_id, auth_defer_msg); | |
2110 | break; | |
2111 | ||
2112 | case BAD64: | |
2113 | s = ss = US"501 Invalid base64 data"; | |
2114 | break; | |
2115 | ||
2116 | case CANCELLED: | |
2117 | s = ss = US"501 Authentication cancelled"; | |
2118 | break; | |
2119 | ||
2120 | case UNEXPECTED: | |
2121 | s = ss = US"553 Initial data not expected"; | |
2122 | break; | |
2123 | ||
2124 | case FAIL: | |
2125 | s = US"535 Incorrect authentication data"; | |
2126 | ss = string_sprintf("535 Incorrect authentication data%s", set_id); | |
2127 | break; | |
2128 | ||
2129 | default: | |
2130 | s = US"435 Internal error"; | |
2131 | ss = string_sprintf("435 Internal error%s: return %d from authentication " | |
2132 | "check", set_id, c); | |
2133 | break; | |
2134 | } | |
2135 | ||
2136 | smtp_printf("%s\r\n", s); | |
2137 | if (c != OK) | |
2138 | log_write(0, LOG_MAIN|LOG_REJECT, "%s authenticator failed for %s: %s", | |
2139 | au->name, host_and_ident(FALSE), ss); | |
2140 | ||
2141 | break; /* AUTH_CMD */ | |
2142 | ||
2143 | /* The HELO/EHLO commands are permitted to appear in the middle of a | |
2144 | session as well as at the beginning. They have the effect of a reset in | |
2145 | addition to their other functions. Their absence at the start cannot be | |
2146 | taken to be an error. | |
2147 | ||
2148 | RFC 2821 says: | |
2149 | ||
2150 | If the EHLO command is not acceptable to the SMTP server, 501, 500, | |
2151 | or 502 failure replies MUST be returned as appropriate. The SMTP | |
2152 | server MUST stay in the same state after transmitting these replies | |
2153 | that it was in before the EHLO was received. | |
2154 | ||
2155 | Therefore, we do not do the reset until after checking the command for | |
2156 | acceptability. This change was made for Exim release 4.11. Previously | |
2157 | it did the reset first. */ | |
2158 | ||
2159 | case HELO_CMD: | |
2160 | hello = US"HELO"; | |
2161 | esmtp = FALSE; | |
2162 | goto HELO_EHLO; | |
2163 | ||
2164 | case EHLO_CMD: | |
2165 | hello = US"EHLO"; | |
2166 | esmtp = TRUE; | |
2167 | ||
2168 | HELO_EHLO: /* Common code for HELO and EHLO */ | |
2169 | cmd_list[CMD_LIST_HELO].is_mail_cmd = FALSE; | |
2170 | cmd_list[CMD_LIST_EHLO].is_mail_cmd = FALSE; | |
2171 | ||
2172 | /* Reject the HELO if its argument was invalid or non-existent. A | |
2173 | successful check causes the argument to be saved in malloc store. */ | |
2174 | ||
2175 | if (!check_helo(smtp_data)) | |
2176 | { | |
2177 | smtp_printf("501 Syntactically invalid %s argument(s)\r\n", hello); | |
2178 | ||
2179 | log_write(0, LOG_MAIN|LOG_REJECT, "rejected %s from %s: syntactically " | |
2180 | "invalid argument(s): %s", hello, host_and_ident(FALSE), | |
2181 | (*smtp_data == 0)? US"(no argument given)" : | |
2182 | string_printing(smtp_data)); | |
2183 | ||
2184 | if (++synprot_error_count > smtp_max_synprot_errors) | |
2185 | { | |
2186 | log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many " | |
2187 | "syntax or protocol errors (last command was \"%s\")", | |
2188 | host_and_ident(FALSE), cmd_buffer); | |
2189 | done = 1; | |
2190 | } | |
2191 | ||
2192 | break; | |
2193 | } | |
2194 | ||
2195 | /* If sender_host_unknown is true, we have got here via the -bs interface, | |
2196 | not called from inetd. Otherwise, we are running an IP connection and the | |
2197 | host address will be set. If the helo name is the primary name of this | |
2198 | host and we haven't done a reverse lookup, force one now. If helo_required | |
2199 | is set, ensure that the HELO name matches the actual host. If helo_verify | |
2200 | is set, do the same check, but softly. */ | |
2201 | ||
2202 | if (!sender_host_unknown) | |
2203 | { | |
2204 | BOOL old_helo_verified = helo_verified; | |
2205 | uschar *p = smtp_data; | |
2206 | ||
2207 | while (*p != 0 && !isspace(*p)) { *p = tolower(*p); p++; } | |
2208 | *p = 0; | |
2209 | ||
2210 | /* Force a reverse lookup if HELO quoted something in helo_lookup_domains | |
2211 | because otherwise the log can be confusing. */ | |
2212 | ||
2213 | if (sender_host_name == NULL && | |
2214 | (deliver_domain = sender_helo_name, /* set $domain */ | |
2215 | match_isinlist(sender_helo_name, &helo_lookup_domains, 0, | |
2216 | &domainlist_anchor, NULL, MCL_DOMAIN, TRUE, NULL)) == OK) | |
2217 | (void)host_name_lookup(); | |
2218 | ||
2219 | /* Rebuild the fullhost info to include the HELO name (and the real name | |
2220 | if it was looked up.) */ | |
2221 | ||
2222 | host_build_sender_fullhost(); /* Rebuild */ | |
2223 | set_process_info("handling%s incoming connection from %s", | |
2224 | (tls_active >= 0)? " TLS" : "", host_and_ident(FALSE)); | |
2225 | ||
2226 | /* Verify if configured. This doesn't give much security, but it does | |
2227 | make some people happy to be able to do it. Note that HELO is legitimately | |
2228 | allowed to quote an address literal. Allow for IPv6 ::ffff: literals. */ | |
2229 | ||
2230 | helo_verified = FALSE; | |
2231 | if (helo_required || helo_verify) | |
2232 | { | |
2233 | BOOL tempfail = FALSE; | |
2234 | ||
2235 | HDEBUG(D_receive) debug_printf("verifying %s %s\n", hello, | |
2236 | sender_helo_name); | |
2237 | if (sender_helo_name[0] == '[') | |
2238 | { | |
2239 | helo_verified = Ustrncmp(sender_helo_name+1, sender_host_address, | |
2240 | Ustrlen(sender_host_address)) == 0; | |
2241 | ||
2242 | #if HAVE_IPV6 | |
2243 | if (!helo_verified) | |
2244 | { | |
2245 | if (strncmpic(sender_host_address, US"::ffff:", 7) == 0) | |
2246 | helo_verified = Ustrncmp(sender_helo_name + 1, | |
2247 | sender_host_address + 7, Ustrlen(sender_host_address) - 7) == 0; | |
2248 | } | |
2249 | #endif | |
2250 | ||
2251 | HDEBUG(D_receive) | |
2252 | { if (helo_verified) debug_printf("matched host address\n"); } | |
2253 | } | |
2254 | ||
2255 | /* Do a reverse lookup if one hasn't already given a positive or | |
2256 | negative response. If that fails, or the name doesn't match, try | |
2257 | checking with a forward lookup. */ | |
2258 | ||
2259 | else | |
2260 | { | |
2261 | if (sender_host_name == NULL && !host_lookup_failed) | |
2262 | tempfail = host_name_lookup() == DEFER; | |
2263 | ||
2264 | /* If a host name is known, check it and all its aliases. */ | |
2265 | ||
2266 | if (sender_host_name != NULL) | |
2267 | { | |
2268 | helo_verified = strcmpic(sender_host_name, sender_helo_name) == 0; | |
2269 | ||
2270 | if (helo_verified) | |
2271 | { | |
2272 | HDEBUG(D_receive) debug_printf("matched host name\n"); | |
2273 | } | |
2274 | else | |
2275 | { | |
2276 | uschar **aliases = sender_host_aliases; | |
2277 | while (*aliases != NULL) | |
2278 | { | |
2279 | helo_verified = strcmpic(*aliases++, sender_helo_name) == 0; | |
2280 | if (helo_verified) break; | |
2281 | } | |
2282 | HDEBUG(D_receive) | |
2283 | { | |
2284 | if (helo_verified) | |
2285 | debug_printf("matched alias %s\n", *(--aliases)); | |
2286 | } | |
2287 | } | |
2288 | } | |
2289 | ||
2290 | /* Final attempt: try a forward lookup of the helo name */ | |
2291 | ||
2292 | if (!helo_verified) | |
2293 | { | |
2294 | int rc; | |
2295 | host_item h; | |
2296 | h.name = sender_helo_name; | |
2297 | h.address = NULL; | |
2298 | h.mx = MX_NONE; | |
2299 | h.next = NULL; | |
2300 | HDEBUG(D_receive) debug_printf("getting IP address for %s\n", | |
2301 | sender_helo_name); | |
2302 | rc = host_find_byname(&h, NULL, NULL, TRUE); | |
2303 | if (rc == HOST_FOUND || rc == HOST_FOUND_LOCAL) | |
2304 | { | |
2305 | host_item *hh = &h; | |
2306 | while (hh != NULL) | |
2307 | { | |
2308 | if (Ustrcmp(hh->address, sender_host_address) == 0) | |
2309 | { | |
2310 | helo_verified = TRUE; | |
2311 | HDEBUG(D_receive) | |
2312 | debug_printf("IP address for %s matches calling address\n", | |
2313 | sender_helo_name); | |
2314 | break; | |
2315 | } | |
2316 | hh = hh->next; | |
2317 | } | |
2318 | } | |
2319 | } | |
2320 | } | |
2321 | ||
2322 | /* Verification failed. A temporary lookup failure gives a temporary | |
2323 | error. */ | |
2324 | ||
2325 | if (!helo_verified) | |
2326 | { | |
2327 | if (helo_required) | |
2328 | { | |
2329 | smtp_printf("%d %s argument does not match calling host\r\n", | |
2330 | tempfail? 451 : 550, hello); | |
2331 | log_write(0, LOG_MAIN|LOG_REJECT, "%srejected \"%s %s\" from %s", | |
2332 | tempfail? "temporarily " : "", | |
2333 | hello, sender_helo_name, host_and_ident(FALSE)); | |
2334 | helo_verified = old_helo_verified; | |
2335 | break; /* End of HELO/EHLO processing */ | |
2336 | } | |
2337 | HDEBUG(D_all) debug_printf("%s verification failed but host is in " | |
2338 | "helo_try_verify_hosts\n", hello); | |
2339 | } | |
2340 | } | |
2341 | } | |
2342 | ||
2343 | /* Apply an ACL check if one is defined */ | |
2344 | ||
2345 | if (acl_smtp_helo != NULL) | |
2346 | { | |
2347 | rc = acl_check(ACL_WHERE_HELO, smtp_data, acl_smtp_helo, &user_msg, | |
2348 | &log_msg); | |
2349 | if (rc != OK) | |
2350 | { | |
2351 | done = smtp_handle_acl_fail(ACL_WHERE_HELO, rc, user_msg, log_msg); | |
2352 | sender_helo_name = NULL; | |
2353 | host_build_sender_fullhost(); /* Rebuild */ | |
2354 | break; | |
2355 | } | |
2356 | } | |
2357 | ||
2358 | /* The EHLO/HELO command is acceptable. Reset the protocol and the state, | |
2359 | abandoning any previous message. */ | |
2360 | ||
2361 | received_protocol = (esmtp? | |
2362 | protocols[pextend + | |
2363 | ((sender_host_authenticated != NULL)? pauthed : 0) + | |
2364 | ((tls_active >= 0)? pcrpted : 0)] | |
2365 | : | |
981756db | 2366 | protocols[pnormal + ((tls_active >= 0)? pcrpted : 0)]) |
059ec3d9 PH |
2367 | + |
2368 | ((sender_host_address != NULL)? pnlocal : 0); | |
2369 | ||
2370 | smtp_reset(reset_point); | |
2371 | toomany = FALSE; | |
2372 | ||
2373 | /* Generate an OK reply, including the ident if present, and also | |
2374 | the IP address if present. Reflecting back the ident is intended | |
2375 | as a deterrent to mail forgers. For maximum efficiency, and also | |
2376 | because some broken systems expect each response to be in a single | |
2377 | packet, arrange that it is sent in one write(). */ | |
2378 | ||
2379 | auth_advertised = FALSE; | |
2380 | pipelining_advertised = FALSE; | |
2381 | #ifdef SUPPORT_TLS | |
2382 | tls_advertised = FALSE; | |
2383 | #endif | |
2384 | ||
2385 | s = string_sprintf("250 %s Hello %s%s%s", | |
2386 | smtp_active_hostname, | |
2387 | (sender_ident == NULL)? US"" : sender_ident, | |
2388 | (sender_ident == NULL)? US"" : US" at ", | |
2389 | (sender_host_name == NULL)? sender_helo_name : sender_host_name); | |
2390 | ||
2391 | ptr = Ustrlen(s); | |
2392 | size = ptr + 1; | |
2393 | ||
2394 | if (sender_host_address != NULL) | |
2395 | { | |
2396 | s = string_cat(s, &size, &ptr, US" [", 2); | |
2397 | s = string_cat(s, &size, &ptr, sender_host_address, | |
2398 | Ustrlen(sender_host_address)); | |
2399 | s = string_cat(s, &size, &ptr, US"]", 1); | |
2400 | } | |
2401 | ||
2402 | s = string_cat(s, &size, &ptr, US"\r\n", 2); | |
2403 | ||
2404 | /* If we received EHLO, we must create a multiline response which includes | |
2405 | the functions supported. */ | |
2406 | ||
2407 | if (esmtp) | |
2408 | { | |
2409 | s[3] = '-'; | |
2410 | ||
2411 | /* I'm not entirely happy with this, as an MTA is supposed to check | |
2412 | that it has enough room to accept a message of maximum size before | |
2413 | it sends this. However, there seems little point in not sending it. | |
2414 | The actual size check happens later at MAIL FROM time. By postponing it | |
2415 | till then, VRFY and EXPN can be used after EHLO when space is short. */ | |
2416 | ||
2417 | if (thismessage_size_limit > 0) | |
2418 | { | |
2419 | sprintf(CS big_buffer, "250-SIZE %d\r\n", thismessage_size_limit); | |
2420 | s = string_cat(s, &size, &ptr, big_buffer, Ustrlen(big_buffer)); | |
2421 | } | |
2422 | else | |
2423 | { | |
2424 | s = string_cat(s, &size, &ptr, US"250-SIZE\r\n", 10); | |
2425 | } | |
2426 | ||
2427 | /* Exim does not do protocol conversion or data conversion. It is 8-bit | |
2428 | clean; if it has an 8-bit character in its hand, it just sends it. It | |
2429 | cannot therefore specify 8BITMIME and remain consistent with the RFCs. | |
2430 | However, some users want this option simply in order to stop MUAs | |
2431 | mangling messages that contain top-bit-set characters. It is therefore | |
2432 | provided as an option. */ | |
2433 | ||
2434 | if (accept_8bitmime) | |
2435 | s = string_cat(s, &size, &ptr, US"250-8BITMIME\r\n", 14); | |
2436 | ||
2437 | /* Advertise ETRN if there's an ACL checking whether a host is | |
2438 | permitted to issue it; a check is made when any host actually tries. */ | |
2439 | ||
2440 | if (acl_smtp_etrn != NULL) | |
2441 | { | |
2442 | s = string_cat(s, &size, &ptr, US"250-ETRN\r\n", 10); | |
2443 | } | |
2444 | ||
2445 | /* Advertise EXPN if there's an ACL checking whether a host is | |
2446 | permitted to issue it; a check is made when any host actually tries. */ | |
2447 | ||
2448 | if (acl_smtp_expn != NULL) | |
2449 | { | |
2450 | s = string_cat(s, &size, &ptr, US"250-EXPN\r\n", 10); | |
2451 | } | |
2452 | ||
2453 | /* Exim is quite happy with pipelining, so let the other end know that | |
2454 | it is safe to use it, unless advertising is disabled. */ | |
2455 | ||
2456 | if (verify_check_host(&pipelining_advertise_hosts) == OK) | |
2457 | { | |
2458 | s = string_cat(s, &size, &ptr, US"250-PIPELINING\r\n", 16); | |
2459 | sync_cmd_limit = NON_SYNC_CMD_PIPELINING; | |
2460 | pipelining_advertised = TRUE; | |
2461 | } | |
2462 | ||
2463 | /* If any server authentication mechanisms are configured, advertise | |
2464 | them if the current host is in auth_advertise_hosts. The problem with | |
2465 | advertising always is that some clients then require users to | |
2466 | authenticate (and aren't configurable otherwise) even though it may not | |
2467 | be necessary (e.g. if the host is in host_accept_relay). | |
2468 | ||
2469 | RFC 2222 states that SASL mechanism names contain only upper case | |
2470 | letters, so output the names in upper case, though we actually recognize | |
2471 | them in either case in the AUTH command. */ | |
2472 | ||
2473 | if (auths != NULL) | |
2474 | { | |
2475 | if (verify_check_host(&auth_advertise_hosts) == OK) | |
2476 | { | |
2477 | auth_instance *au; | |
2478 | BOOL first = TRUE; | |
2479 | for (au = auths; au != NULL; au = au->next) | |
2480 | { | |
2481 | if (au->server && (au->advertise_condition == NULL || | |
2482 | expand_check_condition(au->advertise_condition, au->name, | |
2483 | US"authenticator"))) | |
2484 | { | |
2485 | int saveptr; | |
2486 | if (first) | |
2487 | { | |
2488 | s = string_cat(s, &size, &ptr, US"250-AUTH", 8); | |
2489 | first = FALSE; | |
2490 | auth_advertised = TRUE; | |
2491 | } | |
2492 | saveptr = ptr; | |
2493 | s = string_cat(s, &size, &ptr, US" ", 1); | |
2494 | s = string_cat(s, &size, &ptr, au->public_name, | |
2495 | Ustrlen(au->public_name)); | |
2496 | while (++saveptr < ptr) s[saveptr] = toupper(s[saveptr]); | |
2497 | au->advertised = TRUE; | |
2498 | } | |
2499 | else au->advertised = FALSE; | |
2500 | } | |
2501 | if (!first) s = string_cat(s, &size, &ptr, US"\r\n", 2); | |
2502 | } | |
2503 | } | |
2504 | ||
2505 | /* Advertise TLS (Transport Level Security) aka SSL (Secure Socket Layer) | |
2506 | if it has been included in the binary, and the host matches | |
2507 | tls_advertise_hosts. We must *not* advertise if we are already in a | |
2508 | secure connection. */ | |
2509 | ||
2510 | #ifdef SUPPORT_TLS | |
2511 | if (tls_active < 0 && | |
2512 | verify_check_host(&tls_advertise_hosts) != FAIL) | |
2513 | { | |
2514 | s = string_cat(s, &size, &ptr, US"250-STARTTLS\r\n", 14); | |
2515 | tls_advertised = TRUE; | |
2516 | } | |
2517 | #endif | |
2518 | ||
2519 | /* Finish off the multiline reply with one that is always available. */ | |
2520 | ||
2521 | s = string_cat(s, &size, &ptr, US"250 HELP\r\n", 10); | |
2522 | } | |
2523 | ||
2524 | /* Terminate the string (for debug), write it, and note that HELO/EHLO | |
2525 | has been seen. */ | |
2526 | ||
2527 | s[ptr] = 0; | |
2528 | ||
2529 | #ifdef SUPPORT_TLS | |
2530 | if (tls_active >= 0) (void)tls_write(s, ptr); else | |
2531 | #endif | |
2532 | ||
2533 | fwrite(s, 1, ptr, smtp_out); | |
2534 | DEBUG(D_receive) debug_printf("SMTP>> %s", s); | |
2535 | helo_seen = TRUE; | |
2536 | break; /* HELO/EHLO */ | |
2537 | ||
2538 | ||
2539 | /* The MAIL command requires an address as an operand. All we do | |
2540 | here is to parse it for syntactic correctness. The form "<>" is | |
2541 | a special case which converts into an empty string. The start/end | |
2542 | pointers in the original are not used further for this address, as | |
2543 | it is the canonical extracted address which is all that is kept. */ | |
2544 | ||
2545 | case MAIL_CMD: | |
2546 | smtp_mailcmd_count++; /* Count for limit and ratelimit */ | |
2547 | was_rej_mail = TRUE; /* Reset if accepted */ | |
2548 | ||
2549 | if (helo_required && !helo_seen) | |
2550 | { | |
2551 | smtp_printf("503 HELO or EHLO required\r\n"); | |
2552 | log_write(0, LOG_MAIN|LOG_REJECT, "rejected MAIL from %s: no " | |
2553 | "HELO/EHLO given", host_and_ident(FALSE)); | |
2554 | break; | |
2555 | } | |
2556 | ||
2557 | if (sender_address != NULL) | |
2558 | { | |
2559 | done = synprot_error(L_smtp_protocol_error, 503, NULL, | |
2560 | US"sender already given"); | |
2561 | break; | |
2562 | } | |
2563 | ||
2564 | if (smtp_data[0] == 0) | |
2565 | { | |
2566 | done = synprot_error(L_smtp_protocol_error, 501, NULL, | |
2567 | US"MAIL must have an address operand"); | |
2568 | break; | |
2569 | } | |
2570 | ||
2571 | /* Check to see if the limit for messages per connection would be | |
2572 | exceeded by accepting further messages. */ | |
2573 | ||
2574 | if (smtp_accept_max_per_connection > 0 && | |
2575 | smtp_mailcmd_count > smtp_accept_max_per_connection) | |
2576 | { | |
2577 | smtp_printf("421 too many messages in this connection\r\n"); | |
2578 | log_write(0, LOG_MAIN|LOG_REJECT, "rejected MAIL command %s: too many " | |
2579 | "messages in one connection", host_and_ident(TRUE)); | |
2580 | break; | |
2581 | } | |
2582 | ||
2583 | /* Reset for start of message - even if this is going to fail, we | |
2584 | obviously need to throw away any previous data. */ | |
2585 | ||
2586 | smtp_reset(reset_point); | |
2587 | toomany = FALSE; | |
2588 | sender_data = recipient_data = NULL; | |
2589 | ||
2590 | /* Loop, checking for ESMTP additions to the MAIL FROM command. */ | |
2591 | ||
2592 | if (esmtp) for(;;) | |
2593 | { | |
2594 | uschar *name, *value, *end; | |
2595 | unsigned long int size; | |
2596 | ||
2597 | if (!extract_option(&name, &value)) break; | |
2598 | ||
2599 | /* Handle SIZE= by reading the value. We don't do the check till later, | |
2600 | in order to be able to log the sender address on failure. */ | |
2601 | ||
2602 | if (strcmpic(name, US"SIZE") == 0 && | |
2603 | ((size = (int)Ustrtoul(value, &end, 10)), *end == 0)) | |
2604 | { | |
2605 | if ((size == ULONG_MAX && errno == ERANGE) || size > INT_MAX) | |
2606 | size = INT_MAX; | |
2607 | message_size = (int)size; | |
2608 | } | |
2609 | ||
2610 | /* If this session was initiated with EHLO and accept_8bitmime is set, | |
2611 | Exim will have indicated that it supports the BODY=8BITMIME option. In | |
2612 | fact, it does not support this according to the RFCs, in that it does not | |
2613 | take any special action for forwarding messages containing 8-bit | |
2614 | characters. That is why accept_8bitmime is not the default setting, but | |
2615 | some sites want the action that is provided. We recognize both "8BITMIME" | |
2616 | and "7BIT" as body types, but take no action. */ | |
2617 | ||
2618 | else if (accept_8bitmime && strcmpic(name, US"BODY") == 0 && | |
2619 | (strcmpic(value, US"8BITMIME") == 0 || | |
2620 | strcmpic(value, US"7BIT") == 0)) {} | |
2621 | ||
2622 | /* Handle the AUTH extension. If the value given is not "<>" and either | |
2623 | the ACL says "yes" or there is no ACL but the sending host is | |
2624 | authenticated, we set it up as the authenticated sender. However, if the | |
2625 | authenticator set a condition to be tested, we ignore AUTH on MAIL unless | |
2626 | the condition is met. The value of AUTH is an xtext, which means that +, | |
2627 | = and cntrl chars are coded in hex; however "<>" is unaffected by this | |
2628 | coding. */ | |
2629 | ||
2630 | else if (strcmpic(name, US"AUTH") == 0) | |
2631 | { | |
2632 | if (Ustrcmp(value, "<>") != 0) | |
2633 | { | |
2634 | int rc; | |
2635 | uschar *ignore_msg; | |
2636 | ||
2637 | if (auth_xtextdecode(value, &authenticated_sender) < 0) | |
2638 | { | |
2639 | /* Put back terminator overrides for error message */ | |
2640 | name[-1] = ' '; | |
2641 | value[-1] = '='; | |
2642 | done = synprot_error(L_smtp_syntax_error, 501, NULL, | |
2643 | US"invalid data for AUTH"); | |
2644 | goto COMMAND_LOOP; | |
2645 | } | |
2646 | ||
2647 | if (acl_smtp_mailauth == NULL) | |
2648 | { | |
2649 | ignore_msg = US"client not authenticated"; | |
2650 | rc = (sender_host_authenticated != NULL)? OK : FAIL; | |
2651 | } | |
2652 | else | |
2653 | { | |
2654 | ignore_msg = US"rejected by ACL"; | |
2655 | rc = acl_check(ACL_WHERE_MAILAUTH, NULL, acl_smtp_mailauth, | |
2656 | &user_msg, &log_msg); | |
2657 | } | |
2658 | ||
2659 | switch (rc) | |
2660 | { | |
2661 | case OK: | |
2662 | if (authenticated_by == NULL || | |
2663 | authenticated_by->mail_auth_condition == NULL || | |
2664 | expand_check_condition(authenticated_by->mail_auth_condition, | |
2665 | authenticated_by->name, US"authenticator")) | |
2666 | break; /* Accept the AUTH */ | |
2667 | ||
2668 | ignore_msg = US"server_mail_auth_condition failed"; | |
2669 | if (authenticated_id != NULL) | |
2670 | ignore_msg = string_sprintf("%s: authenticated ID=\"%s\"", | |
2671 | ignore_msg, authenticated_id); | |
2672 | ||
2673 | /* Fall through */ | |
2674 | ||
2675 | case FAIL: | |
2676 | authenticated_sender = NULL; | |
2677 | log_write(0, LOG_MAIN, "ignoring AUTH=%s from %s (%s)", | |
2678 | value, host_and_ident(TRUE), ignore_msg); | |
2679 | break; | |
2680 | ||
2681 | /* Should only get DEFER or ERROR here. Put back terminator | |
2682 | overrides for error message */ | |
2683 | ||
2684 | default: | |
2685 | name[-1] = ' '; | |
2686 | value[-1] = '='; | |
2687 | (void)smtp_handle_acl_fail(ACL_WHERE_MAILAUTH, rc, user_msg, | |
2688 | log_msg); | |
2689 | goto COMMAND_LOOP; | |
2690 | } | |
2691 | } | |
2692 | } | |
2693 | ||
2694 | /* Unknown option. Stick back the terminator characters and break | |
2695 | the loop. An error for a malformed address will occur. */ | |
2696 | ||
2697 | else | |
2698 | { | |
2699 | name[-1] = ' '; | |
2700 | value[-1] = '='; | |
2701 | break; | |
2702 | } | |
2703 | } | |
2704 | ||
2705 | /* If we have passed the threshold for rate limiting, apply the current | |
2706 | delay, and update it for next time, provided this is a limited host. */ | |
2707 | ||
2708 | if (smtp_mailcmd_count > smtp_rlm_threshold && | |
2709 | verify_check_host(&smtp_ratelimit_hosts) == OK) | |
2710 | { | |
2711 | DEBUG(D_receive) debug_printf("rate limit MAIL: delay %.3g sec\n", | |
2712 | smtp_delay_mail/1000.0); | |
2713 | millisleep((int)smtp_delay_mail); | |
2714 | smtp_delay_mail *= smtp_rlm_factor; | |
2715 | if (smtp_delay_mail > (double)smtp_rlm_limit) | |
2716 | smtp_delay_mail = (double)smtp_rlm_limit; | |
2717 | } | |
2718 | ||
2719 | /* Now extract the address, first applying any SMTP-time rewriting. The | |
2720 | TRUE flag allows "<>" as a sender address. */ | |
2721 | ||
2722 | raw_sender = ((rewrite_existflags & rewrite_smtp) != 0)? | |
2723 | rewrite_one(smtp_data, rewrite_smtp, NULL, FALSE, US"", | |
2724 | global_rewrite_rules) : smtp_data; | |
2725 | ||
2726 | /* rfc821_domains = TRUE; << no longer needed */ | |
2727 | raw_sender = | |
2728 | parse_extract_address(raw_sender, &errmess, &start, &end, &sender_domain, | |
2729 | TRUE); | |
2730 | /* rfc821_domains = FALSE; << no longer needed */ | |
2731 | ||
2732 | if (raw_sender == NULL) | |
2733 | { | |
2734 | done = synprot_error(L_smtp_syntax_error, 501, smtp_data, errmess); | |
2735 | break; | |
2736 | } | |
2737 | ||
2738 | sender_address = raw_sender; | |
2739 | ||
2740 | /* If there is a configured size limit for mail, check that this message | |
2741 | doesn't exceed it. The check is postponed to this point so that the sender | |
2742 | can be logged. */ | |
2743 | ||
2744 | if (thismessage_size_limit > 0 && message_size > thismessage_size_limit) | |
2745 | { | |
2746 | smtp_printf("552 Message size exceeds maximum permitted\r\n"); | |
2747 | log_write(L_size_reject, | |
2748 | LOG_MAIN|LOG_REJECT, "rejected MAIL FROM:<%s> %s: " | |
2749 | "message too big: size%s=%d max=%d", | |
2750 | sender_address, | |
2751 | host_and_ident(TRUE), | |
2752 | (message_size == INT_MAX)? ">" : "", | |
2753 | message_size, | |
2754 | thismessage_size_limit); | |
2755 | sender_address = NULL; | |
2756 | break; | |
2757 | } | |
2758 | ||
2759 | /* Check there is enough space on the disk unless configured not to. | |
2760 | When smtp_check_spool_space is set, the check is for thismessage_size_limit | |
2761 | plus the current message - i.e. we accept the message only if it won't | |
2762 | reduce the space below the threshold. Add 5000 to the size to allow for | |
2763 | overheads such as the Received: line and storing of recipients, etc. | |
2764 | By putting the check here, even when SIZE is not given, it allow VRFY | |
2765 | and EXPN etc. to be used when space is short. */ | |
2766 | ||
2767 | if (!receive_check_fs( | |
2768 | (smtp_check_spool_space && message_size >= 0)? | |
2769 | message_size + 5000 : 0)) | |
2770 | { | |
2771 | smtp_printf("452 Space shortage, please try later\r\n"); | |
2772 | sender_address = NULL; | |
2773 | break; | |
2774 | } | |
2775 | ||
2776 | /* If sender_address is unqualified, reject it, unless this is a locally | |
2777 | generated message, or the sending host or net is permitted to send | |
2778 | unqualified addresses - typically local machines behaving as MUAs - | |
2779 | in which case just qualify the address. The flag is set above at the start | |
2780 | of the SMTP connection. */ | |
2781 | ||
2782 | if (sender_domain == 0 && sender_address[0] != 0) | |
2783 | { | |
2784 | if (allow_unqualified_sender) | |
2785 | { | |
2786 | sender_domain = Ustrlen(sender_address) + 1; | |
2787 | sender_address = rewrite_address_qualify(sender_address, FALSE); | |
2788 | DEBUG(D_receive) debug_printf("unqualified address %s accepted\n", | |
2789 | raw_sender); | |
2790 | } | |
2791 | else | |
2792 | { | |
2793 | smtp_printf("501 %s: sender address must contain a domain\r\n", | |
2794 | smtp_data); | |
2795 | log_write(L_smtp_syntax_error, | |
2796 | LOG_MAIN|LOG_REJECT, | |
2797 | "unqualified sender rejected: <%s> %s%s", | |
2798 | raw_sender, | |
2799 | host_and_ident(TRUE), | |
2800 | host_lookup_msg); | |
2801 | sender_address = NULL; | |
2802 | break; | |
2803 | } | |
2804 | } | |
2805 | ||
2806 | /* Apply an ACL check if one is defined, before responding */ | |
2807 | ||
2808 | rc = (acl_smtp_mail == NULL)? OK : | |
2809 | acl_check(ACL_WHERE_MAIL, NULL, acl_smtp_mail, &user_msg, &log_msg); | |
2810 | ||
2811 | if (rc == OK || rc == DISCARD) | |
2812 | { | |
2813 | smtp_printf("250 OK\r\n"); | |
2814 | smtp_delay_rcpt = smtp_rlr_base; | |
2815 | recipients_discarded = (rc == DISCARD); | |
2816 | was_rej_mail = FALSE; | |
2817 | } | |
2818 | ||
2819 | else | |
2820 | { | |
2821 | done = smtp_handle_acl_fail(ACL_WHERE_MAIL, rc, user_msg, log_msg); | |
2822 | sender_address = NULL; | |
2823 | } | |
2824 | break; | |
2825 | ||
2826 | ||
2827 | /* The RCPT command requires an address as an operand. All we do | |
2828 | here is to parse it for syntactic correctness. There may be any number | |
2829 | of RCPT commands, specifying multiple senders. We build them all into | |
2830 | a data structure that is in argc/argv format. The start/end values | |
2831 | given by parse_extract_address are not used, as we keep only the | |
2832 | extracted address. */ | |
2833 | ||
2834 | case RCPT_CMD: | |
2835 | rcpt_count++; | |
2836 | was_rcpt = TRUE; | |
2837 | ||
2838 | /* There must be a sender address; if the sender was rejected and | |
2839 | pipelining was advertised, we assume the client was pipelining, and do not | |
2840 | count this as a protocol error. Reset was_rej_mail so that further RCPTs | |
2841 | get the same treatment. */ | |
2842 | ||
2843 | if (sender_address == NULL) | |
2844 | { | |
2845 | if (pipelining_advertised && last_was_rej_mail) | |
2846 | { | |
2847 | smtp_printf("503 sender not yet given\r\n"); | |
2848 | was_rej_mail = TRUE; | |
2849 | } | |
2850 | else | |
2851 | { | |
2852 | done = synprot_error(L_smtp_protocol_error, 503, NULL, | |
2853 | US"sender not yet given"); | |
2854 | was_rcpt = FALSE; /* Not a valid RCPT */ | |
2855 | } | |
2856 | rcpt_fail_count++; | |
2857 | break; | |
2858 | } | |
2859 | ||
2860 | /* Check for an operand */ | |
2861 | ||
2862 | if (smtp_data[0] == 0) | |
2863 | { | |
2864 | done = synprot_error(L_smtp_syntax_error, 501, NULL, | |
2865 | US"RCPT must have an address operand"); | |
2866 | rcpt_fail_count++; | |
2867 | break; | |
2868 | } | |
2869 | ||
2870 | /* Apply SMTP rewriting then extract the working address. Don't allow "<>" | |
2871 | as a recipient address */ | |
2872 | ||
2873 | recipient = ((rewrite_existflags & rewrite_smtp) != 0)? | |
2874 | rewrite_one(smtp_data, rewrite_smtp, NULL, FALSE, US"", | |
2875 | global_rewrite_rules) : smtp_data; | |
2876 | ||
2877 | /* rfc821_domains = TRUE; << no longer needed */ | |
2878 | recipient = parse_extract_address(recipient, &errmess, &start, &end, | |
2879 | &recipient_domain, FALSE); | |
2880 | /* rfc821_domains = FALSE; << no longer needed */ | |
2881 | ||
2882 | if (recipient == NULL) | |
2883 | { | |
2884 | done = synprot_error(L_smtp_syntax_error, 501, smtp_data, errmess); | |
2885 | rcpt_fail_count++; | |
2886 | break; | |
2887 | } | |
2888 | ||
2889 | /* If the recipient address is unqualified, reject it, unless this is a | |
2890 | locally generated message. However, unqualified addresses are permitted | |
2891 | from a configured list of hosts and nets - typically when behaving as | |
2892 | MUAs rather than MTAs. Sad that SMTP is used for both types of traffic, | |
2893 | really. The flag is set at the start of the SMTP connection. | |
2894 | ||
2895 | RFC 1123 talks about supporting "the reserved mailbox postmaster"; I always | |
2896 | assumed this meant "reserved local part", but the revision of RFC 821 and | |
2897 | friends now makes it absolutely clear that it means *mailbox*. Consequently | |
2898 | we must always qualify this address, regardless. */ | |
2899 | ||
2900 | if (recipient_domain == 0) | |
2901 | { | |
2902 | if (allow_unqualified_recipient || | |
2903 | strcmpic(recipient, US"postmaster") == 0) | |
2904 | { | |
2905 | DEBUG(D_receive) debug_printf("unqualified address %s accepted\n", | |
2906 | recipient); | |
2907 | recipient_domain = Ustrlen(recipient) + 1; | |
2908 | recipient = rewrite_address_qualify(recipient, TRUE); | |
2909 | } | |
2910 | else | |
2911 | { | |
2912 | rcpt_fail_count++; | |
2913 | smtp_printf("501 %s: recipient address must contain a domain\r\n", | |
2914 | smtp_data); | |
2915 | log_write(L_smtp_syntax_error, | |
2916 | LOG_MAIN|LOG_REJECT, "unqualified recipient rejected: " | |
2917 | "<%s> %s%s", recipient, host_and_ident(TRUE), | |
2918 | host_lookup_msg); | |
2919 | break; | |
2920 | } | |
2921 | } | |
2922 | ||
2923 | /* Check maximum allowed */ | |
2924 | ||
2925 | if (rcpt_count > recipients_max && recipients_max > 0) | |
2926 | { | |
2927 | if (recipients_max_reject) | |
2928 | { | |
2929 | rcpt_fail_count++; | |
2930 | smtp_printf("552 too many recipients\r\n"); | |
2931 | if (!toomany) | |
2932 | log_write(0, LOG_MAIN|LOG_REJECT, "too many recipients: message " | |
2933 | "rejected: sender=<%s> %s", sender_address, host_and_ident(TRUE)); | |
2934 | } | |
2935 | else | |
2936 | { | |
2937 | rcpt_defer_count++; | |
2938 | smtp_printf("452 too many recipients\r\n"); | |
2939 | if (!toomany) | |
2940 | log_write(0, LOG_MAIN|LOG_REJECT, "too many recipients: excess " | |
2941 | "temporarily rejected: sender=<%s> %s", sender_address, | |
2942 | host_and_ident(TRUE)); | |
2943 | } | |
2944 | ||
2945 | toomany = TRUE; | |
2946 | break; | |
2947 | } | |
2948 | ||
2949 | /* If we have passed the threshold for rate limiting, apply the current | |
2950 | delay, and update it for next time, provided this is a limited host. */ | |
2951 | ||
2952 | if (rcpt_count > smtp_rlr_threshold && | |
2953 | verify_check_host(&smtp_ratelimit_hosts) == OK) | |
2954 | { | |
2955 | DEBUG(D_receive) debug_printf("rate limit RCPT: delay %.3g sec\n", | |
2956 | smtp_delay_rcpt/1000.0); | |
2957 | millisleep((int)smtp_delay_rcpt); | |
2958 | smtp_delay_rcpt *= smtp_rlr_factor; | |
2959 | if (smtp_delay_rcpt > (double)smtp_rlr_limit) | |
2960 | smtp_delay_rcpt = (double)smtp_rlr_limit; | |
2961 | } | |
2962 | ||
2963 | /* If the MAIL ACL discarded all the recipients, we bypass ACL checking | |
2964 | for them. Otherwise, check the access control list for this recipient. */ | |
2965 | ||
2966 | rc = recipients_discarded? DISCARD : | |
2967 | acl_check(ACL_WHERE_RCPT, recipient, acl_smtp_rcpt, &user_msg, &log_msg); | |
2968 | ||
2969 | /* The ACL was happy */ | |
2970 | ||
2971 | if (rc == OK) | |
2972 | { | |
2973 | smtp_printf("250 Accepted\r\n"); | |
2974 | receive_add_recipient(recipient, -1); | |
2975 | } | |
2976 | ||
2977 | /* The recipient was discarded */ | |
2978 | ||
2979 | else if (rc == DISCARD) | |
2980 | { | |
2981 | smtp_printf("250 Accepted\r\n"); | |
2982 | rcpt_fail_count++; | |
2983 | discarded = TRUE; | |
2984 | log_write(0, LOG_MAIN|LOG_REJECT, "%s F=<%s> rejected RCPT %s: " | |
2985 | "discarded by %s ACL%s%s", host_and_ident(TRUE), | |
2986 | (sender_address_unrewritten != NULL)? | |
2987 | sender_address_unrewritten : sender_address, | |
2988 | smtp_data, recipients_discarded? "MAIL" : "RCPT", | |
2989 | (log_msg == NULL)? US"" : US": ", | |
2990 | (log_msg == NULL)? US"" : log_msg); | |
2991 | } | |
2992 | ||
2993 | /* Either the ACL failed the address, or it was deferred. */ | |
2994 | ||
2995 | else | |
2996 | { | |
2997 | if (rc == FAIL) rcpt_fail_count++; else rcpt_defer_count++; | |
2998 | done = smtp_handle_acl_fail(ACL_WHERE_RCPT, rc, user_msg, log_msg); | |
2999 | } | |
3000 | break; | |
3001 | ||
3002 | ||
3003 | /* The DATA command is legal only if it follows successful MAIL FROM | |
3004 | and RCPT TO commands. However, if pipelining is advertised, a bad DATA is | |
3005 | not counted as a protocol error if it follows RCPT (which must have been | |
3006 | rejected if there are no recipients.) This function is complete when a | |
3007 | valid DATA command is encountered. | |
3008 | ||
3009 | Note concerning the code used: RFC 2821 says this: | |
3010 | ||
3011 | - If there was no MAIL, or no RCPT, command, or all such commands | |
3012 | were rejected, the server MAY return a "command out of sequence" | |
3013 | (503) or "no valid recipients" (554) reply in response to the | |
3014 | DATA command. | |
3015 | ||
3016 | The example in the pipelining RFC 2920 uses 554, but I use 503 here | |
3017 | because it is the same whether pipelining is in use or not. */ | |
3018 | ||
3019 | case DATA_CMD: | |
3020 | if (!discarded && recipients_count <= 0) | |
3021 | { | |
3022 | if (pipelining_advertised && last_was_rcpt) | |
3023 | smtp_printf("503 valid RCPT command must precede DATA\r\n"); | |
3024 | else | |
3025 | done = synprot_error(L_smtp_protocol_error, 503, NULL, | |
3026 | US"valid RCPT command must precede DATA"); | |
3027 | break; | |
3028 | } | |
3029 | ||
3030 | if (toomany && recipients_max_reject) | |
3031 | { | |
3032 | sender_address = NULL; /* This will allow a new MAIL without RSET */ | |
3033 | sender_address_unrewritten = NULL; | |
3034 | smtp_printf("554 Too many recipients\r\n"); | |
3035 | break; | |
3036 | } | |
5be20824 PH |
3037 | |
3038 | if (acl_smtp_predata == NULL) rc = OK; else | |
3039 | { | |
3040 | enable_dollar_recipients = TRUE; | |
3041 | rc = acl_check(ACL_WHERE_PREDATA, NULL, acl_smtp_predata, &user_msg, | |
3042 | &log_msg); | |
3043 | enable_dollar_recipients = FALSE; | |
3044 | } | |
059ec3d9 PH |
3045 | |
3046 | if (rc == OK) | |
3047 | { | |
3048 | smtp_printf("354 Enter message, ending with \".\" on a line by itself\r\n"); | |
3049 | done = 3; | |
3050 | message_ended = END_NOTENDED; /* Indicate in middle of data */ | |
3051 | } | |
3052 | ||
3053 | /* Either the ACL failed the address, or it was deferred. */ | |
3054 | ||
3055 | else | |
3056 | done = smtp_handle_acl_fail(ACL_WHERE_PREDATA, rc, user_msg, log_msg); | |
3057 | ||
3058 | break; | |
3059 | ||
3060 | ||
3061 | case VRFY_CMD: | |
3062 | rc = acl_check(ACL_WHERE_VRFY, smtp_data, acl_smtp_vrfy, &user_msg, | |
3063 | &log_msg); | |
3064 | if (rc != OK) | |
3065 | done = smtp_handle_acl_fail(ACL_WHERE_VRFY, rc, user_msg, log_msg); | |
3066 | else | |
3067 | { | |
3068 | uschar *address; | |
3069 | uschar *s = NULL; | |
3070 | ||
3071 | /* rfc821_domains = TRUE; << no longer needed */ | |
3072 | address = parse_extract_address(smtp_data, &errmess, &start, &end, | |
3073 | &recipient_domain, FALSE); | |
3074 | /* rfc821_domains = FALSE; << no longer needed */ | |
3075 | ||
3076 | if (address == NULL) | |
3077 | s = string_sprintf("501 %s", errmess); | |
3078 | else | |
3079 | { | |
3080 | address_item *addr = deliver_make_addr(address, FALSE); | |
3081 | switch(verify_address(addr, NULL, vopt_is_recipient | vopt_qualify, -1, | |
4deaf07d | 3082 | -1, -1, NULL, NULL, NULL)) |
059ec3d9 PH |
3083 | { |
3084 | case OK: | |
3085 | s = string_sprintf("250 <%s> is deliverable", address); | |
3086 | break; | |
3087 | ||
3088 | case DEFER: | |
3089 | s = (addr->message != NULL)? | |
3090 | string_sprintf("451 <%s> %s", address, addr->message) : | |
3091 | string_sprintf("451 Cannot resolve <%s> at this time", address); | |
3092 | break; | |
3093 | ||
3094 | case FAIL: | |
3095 | s = (addr->message != NULL)? | |
3096 | string_sprintf("550 <%s> %s", address, addr->message) : | |
3097 | string_sprintf("550 <%s> is not deliverable", address); | |
3098 | log_write(0, LOG_MAIN, "VRFY failed for %s %s", | |
3099 | smtp_data, host_and_ident(TRUE)); | |
3100 | break; | |
3101 | } | |
3102 | } | |
3103 | ||
3104 | smtp_printf("%s\r\n", s); | |
3105 | } | |
3106 | break; | |
3107 | ||
3108 | ||
3109 | case EXPN_CMD: | |
3110 | rc = acl_check(ACL_WHERE_EXPN, smtp_data, acl_smtp_expn, &user_msg, | |
3111 | &log_msg); | |
3112 | if (rc != OK) | |
3113 | done = smtp_handle_acl_fail(ACL_WHERE_EXPN, rc, user_msg, log_msg); | |
3114 | else | |
3115 | { | |
3116 | BOOL save_log_testing_mode = log_testing_mode; | |
3117 | address_test_mode = log_testing_mode = TRUE; | |
3118 | (void) verify_address(deliver_make_addr(smtp_data, FALSE), smtp_out, | |
4deaf07d PH |
3119 | vopt_is_recipient | vopt_qualify | vopt_expn, -1, -1, -1, NULL, NULL, |
3120 | NULL); | |
059ec3d9 PH |
3121 | address_test_mode = FALSE; |
3122 | log_testing_mode = save_log_testing_mode; /* true for -bh */ | |
3123 | } | |
3124 | break; | |
3125 | ||
3126 | ||
3127 | #ifdef SUPPORT_TLS | |
3128 | ||
3129 | case STARTTLS_CMD: | |
3130 | if (!tls_advertised) | |
3131 | { | |
3132 | done = synprot_error(L_smtp_protocol_error, 503, NULL, | |
3133 | US"STARTTLS command used when not advertised"); | |
3134 | break; | |
3135 | } | |
3136 | ||
3137 | /* Apply an ACL check if one is defined */ | |
3138 | ||
3139 | if (acl_smtp_starttls != NULL) | |
3140 | { | |
3141 | rc = acl_check(ACL_WHERE_STARTTLS, NULL, acl_smtp_starttls, &user_msg, | |
3142 | &log_msg); | |
3143 | if (rc != OK) | |
3144 | { | |
3145 | done = smtp_handle_acl_fail(ACL_WHERE_STARTTLS, rc, user_msg, log_msg); | |
3146 | break; | |
3147 | } | |
3148 | } | |
3149 | ||
3150 | /* RFC 2487 is not clear on when this command may be sent, though it | |
3151 | does state that all information previously obtained from the client | |
3152 | must be discarded if a TLS session is started. It seems reasonble to | |
3153 | do an implied RSET when STARTTLS is received. */ | |
3154 | ||
3155 | incomplete_transaction_log(US"STARTTLS"); | |
3156 | smtp_reset(reset_point); | |
3157 | toomany = FALSE; | |
3158 | cmd_list[CMD_LIST_STARTTLS].is_mail_cmd = FALSE; | |
3159 | ||
3160 | /* Attempt to start up a TLS session, and if successful, discard all | |
3161 | knowledge that was obtained previously. At least, that's what the RFC says, | |
3162 | and that's what happens by default. However, in order to work round YAEB, | |
3163 | there is an option to remember the esmtp state. Sigh. | |
3164 | ||
3165 | We must allow for an extra EHLO command and an extra AUTH command after | |
3166 | STARTTLS that don't add to the nonmail command count. */ | |
3167 | ||
3168 | if ((rc = tls_server_start(tls_require_ciphers)) == OK) | |
3169 | { | |
3170 | if (!tls_remember_esmtp) | |
3171 | helo_seen = esmtp = auth_advertised = pipelining_advertised = FALSE; | |
3172 | cmd_list[CMD_LIST_EHLO].is_mail_cmd = TRUE; | |
3173 | cmd_list[CMD_LIST_AUTH].is_mail_cmd = TRUE; | |
3174 | if (sender_helo_name != NULL) | |
3175 | { | |
3176 | store_free(sender_helo_name); | |
3177 | sender_helo_name = NULL; | |
3178 | host_build_sender_fullhost(); /* Rebuild */ | |
3179 | set_process_info("handling incoming TLS connection from %s", | |
3180 | host_and_ident(FALSE)); | |
3181 | } | |
3182 | received_protocol = (esmtp? | |
3183 | protocols[pextend + pcrpted + | |
3184 | ((sender_host_authenticated != NULL)? pauthed : 0)] | |
3185 | : | |
981756db | 3186 | protocols[pnormal + pcrpted]) |
059ec3d9 PH |
3187 | + |
3188 | ((sender_host_address != NULL)? pnlocal : 0); | |
3189 | ||
3190 | sender_host_authenticated = NULL; | |
3191 | authenticated_id = NULL; | |
3192 | sync_cmd_limit = NON_SYNC_CMD_NON_PIPELINING; | |
3193 | DEBUG(D_tls) debug_printf("TLS active\n"); | |
3194 | break; /* Successful STARTTLS */ | |
3195 | } | |
3196 | ||
3197 | /* Some local configuration problem was discovered before actually trying | |
3198 | to do a TLS handshake; give a temporary error. */ | |
3199 | ||
3200 | else if (rc == DEFER) | |
3201 | { | |
3202 | smtp_printf("454 TLS currently unavailable\r\n"); | |
3203 | break; | |
3204 | } | |
3205 | ||
3206 | /* Hard failure. Reject everything except QUIT or closed connection. One | |
3207 | cause for failure is a nested STARTTLS, in which case tls_active remains | |
3208 | set, but we must still reject all incoming commands. */ | |
3209 | ||
3210 | DEBUG(D_tls) debug_printf("TLS failed to start\n"); | |
3211 | while (done <= 0) | |
3212 | { | |
3213 | switch(smtp_read_command(FALSE)) | |
3214 | { | |
3215 | case EOF_CMD: | |
3216 | log_write(L_smtp_connection, LOG_MAIN, "%s closed by EOF", | |
3217 | smtp_get_connection_info()); | |
3218 | done = 2; | |
3219 | break; | |
3220 | ||
3221 | case QUIT_CMD: | |
3222 | smtp_printf("221 %s closing connection\r\n", smtp_active_hostname); | |
3223 | log_write(L_smtp_connection, LOG_MAIN, "%s closed by QUIT", | |
3224 | smtp_get_connection_info()); | |
3225 | done = 2; | |
3226 | break; | |
3227 | ||
3228 | default: | |
3229 | smtp_printf("554 Security failure\r\n"); | |
3230 | break; | |
3231 | } | |
3232 | } | |
3233 | tls_close(TRUE); | |
3234 | break; | |
3235 | #endif | |
3236 | ||
3237 | ||
3238 | /* The ACL for QUIT is provided for gathering statistical information or | |
3239 | similar; it does not affect the response code, but it can supply a custom | |
3240 | message. */ | |
3241 | ||
3242 | case QUIT_CMD: | |
3243 | incomplete_transaction_log(US"QUIT"); | |
3244 | ||
3245 | if (acl_smtp_quit != NULL) | |
3246 | { | |
3247 | rc = acl_check(ACL_WHERE_QUIT, US"", acl_smtp_quit,&user_msg,&log_msg); | |
3248 | if (rc == ERROR) | |
3249 | log_write(0, LOG_MAIN|LOG_PANIC, "ACL for QUIT returned ERROR: %s", | |
3250 | log_msg); | |
3251 | } | |
3252 | else user_msg = NULL; | |
3253 | ||
3254 | if (user_msg == NULL) | |
3255 | smtp_printf("221 %s closing connection\r\n", smtp_active_hostname); | |
3256 | else | |
3257 | smtp_printf("221 %s\r\n", user_msg); | |
3258 | ||
3259 | #ifdef SUPPORT_TLS | |
3260 | tls_close(TRUE); | |
3261 | #endif | |
3262 | ||
3263 | done = 2; | |
3264 | log_write(L_smtp_connection, LOG_MAIN, "%s closed by QUIT", | |
3265 | smtp_get_connection_info()); | |
3266 | break; | |
3267 | ||
3268 | ||
3269 | case RSET_CMD: | |
3270 | incomplete_transaction_log(US"RSET"); | |
3271 | smtp_reset(reset_point); | |
3272 | toomany = FALSE; | |
3273 | smtp_printf("250 Reset OK\r\n"); | |
3274 | cmd_list[CMD_LIST_RSET].is_mail_cmd = FALSE; | |
3275 | break; | |
3276 | ||
3277 | ||
3278 | case NOOP_CMD: | |
3279 | smtp_printf("250 OK\r\n"); | |
3280 | break; | |
3281 | ||
3282 | ||
3283 | /* Show ETRN/EXPN/VRFY if there's | |
3284 | an ACL for checking hosts; if actually used, a check will be done for | |
3285 | permitted hosts. */ | |
3286 | ||
3287 | case HELP_CMD: | |
3288 | smtp_printf("214-Commands supported:\r\n"); | |
3289 | { | |
3290 | uschar buffer[256]; | |
3291 | buffer[0] = 0; | |
3292 | Ustrcat(buffer, " AUTH"); | |
3293 | #ifdef SUPPORT_TLS | |
3294 | Ustrcat(buffer, " STARTTLS"); | |
3295 | #endif | |
3296 | Ustrcat(buffer, " HELO EHLO MAIL RCPT DATA"); | |
3297 | Ustrcat(buffer, " NOOP QUIT RSET HELP"); | |
3298 | if (acl_smtp_etrn != NULL) Ustrcat(buffer, " ETRN"); | |
3299 | if (acl_smtp_expn != NULL) Ustrcat(buffer, " EXPN"); | |
3300 | if (acl_smtp_vrfy != NULL) Ustrcat(buffer, " VRFY"); | |
3301 | smtp_printf("214%s\r\n", buffer); | |
3302 | } | |
3303 | break; | |
3304 | ||
3305 | ||
3306 | case EOF_CMD: | |
3307 | incomplete_transaction_log(US"connection lost"); | |
3308 | smtp_printf("421 %s lost input connection\r\n", smtp_active_hostname); | |
3309 | ||
3310 | /* Don't log by default unless in the middle of a message, as some mailers | |
3311 | just drop the call rather than sending QUIT, and it clutters up the logs. | |
3312 | */ | |
3313 | ||
3314 | if (sender_address != NULL || recipients_count > 0) | |
3315 | log_write(L_lost_incoming_connection, | |
3316 | LOG_MAIN, | |
3317 | "unexpected %s while reading SMTP command from %s%s", | |
3318 | sender_host_unknown? "EOF" : "disconnection", | |
3319 | host_and_ident(FALSE), smtp_read_error); | |
3320 | ||
3321 | else log_write(L_smtp_connection, LOG_MAIN, "%s lost%s", | |
3322 | smtp_get_connection_info(), smtp_read_error); | |
3323 | ||
3324 | done = 1; | |
3325 | break; | |
3326 | ||
3327 | ||
3328 | case ETRN_CMD: | |
3329 | if (sender_address != NULL) | |
3330 | { | |
3331 | done = synprot_error(L_smtp_protocol_error, 503, NULL, | |
3332 | US"ETRN is not permitted inside a transaction"); | |
3333 | break; | |
3334 | } | |
3335 | ||
3336 | log_write(L_etrn, LOG_MAIN, "ETRN %s received from %s", smtp_data, | |
3337 | host_and_ident(FALSE)); | |
3338 | ||
3339 | rc = acl_check(ACL_WHERE_ETRN, smtp_data, acl_smtp_etrn, &user_msg, | |
3340 | &log_msg); | |
3341 | if (rc != OK) | |
3342 | { | |
3343 | done = smtp_handle_acl_fail(ACL_WHERE_ETRN, rc, user_msg, log_msg); | |
3344 | break; | |
3345 | } | |
3346 | ||
3347 | /* Compute the serialization key for this command. */ | |
3348 | ||
3349 | etrn_serialize_key = string_sprintf("etrn-%s\n", smtp_data); | |
3350 | ||
3351 | /* If a command has been specified for running as a result of ETRN, we | |
3352 | permit any argument to ETRN. If not, only the # standard form is permitted, | |
3353 | since that is strictly the only kind of ETRN that can be implemented | |
3354 | according to the RFC. */ | |
3355 | ||
3356 | if (smtp_etrn_command != NULL) | |
3357 | { | |
3358 | uschar *error; | |
3359 | BOOL rc; | |
3360 | etrn_command = smtp_etrn_command; | |
3361 | deliver_domain = smtp_data; | |
3362 | rc = transport_set_up_command(&argv, smtp_etrn_command, TRUE, 0, NULL, | |
3363 | US"ETRN processing", &error); | |
3364 | deliver_domain = NULL; | |
3365 | if (!rc) | |
3366 | { | |
3367 | log_write(0, LOG_MAIN|LOG_PANIC, "failed to set up ETRN command: %s", | |
3368 | error); | |
3369 | smtp_printf("458 Internal failure\r\n"); | |
3370 | break; | |
3371 | } | |
3372 | } | |
3373 | ||
3374 | /* Else set up to call Exim with the -R option. */ | |
3375 | ||
3376 | else | |
3377 | { | |
3378 | if (*smtp_data++ != '#') | |
3379 | { | |
3380 | done = synprot_error(L_smtp_syntax_error, 501, NULL, | |
3381 | US"argument must begin with #"); | |
3382 | break; | |
3383 | } | |
3384 | etrn_command = US"exim -R"; | |
3385 | argv = child_exec_exim(CEE_RETURN_ARGV, TRUE, NULL, TRUE, 2, US"-R", | |
3386 | smtp_data); | |
3387 | } | |
3388 | ||
3389 | /* If we are host-testing, don't actually do anything. */ | |
3390 | ||
3391 | if (host_checking) | |
3392 | { | |
3393 | HDEBUG(D_any) | |
3394 | { | |
3395 | debug_printf("ETRN command is: %s\n", etrn_command); | |
3396 | debug_printf("ETRN command execution skipped\n"); | |
3397 | } | |
3398 | smtp_printf("250 OK\r\n"); | |
3399 | break; | |
3400 | } | |
3401 | ||
3402 | ||
3403 | /* If ETRN queue runs are to be serialized, check the database to | |
3404 | ensure one isn't already running. */ | |
3405 | ||
3406 | if (smtp_etrn_serialize && !enq_start(etrn_serialize_key)) | |
3407 | { | |
3408 | smtp_printf("458 Already processing %s\r\n", smtp_data); | |
3409 | break; | |
3410 | } | |
3411 | ||
3412 | /* Fork a child process and run the command. We don't want to have to | |
3413 | wait for the process at any point, so set SIGCHLD to SIG_IGN before | |
3414 | forking. It should be set that way anyway for external incoming SMTP, | |
3415 | but we save and restore to be tidy. If serialization is required, we | |
3416 | actually run the command in yet another process, so we can wait for it | |
3417 | to complete and then remove the serialization lock. */ | |
3418 | ||
3419 | oldsignal = signal(SIGCHLD, SIG_IGN); | |
3420 | ||
3421 | if ((pid = fork()) == 0) | |
3422 | { | |
3423 | smtp_input = FALSE; /* This process is not associated with the */ | |
3424 | fclose(smtp_in); /* SMTP call any more. */ | |
3425 | fclose(smtp_out); | |
3426 | ||
3427 | signal(SIGCHLD, SIG_DFL); /* Want to catch child */ | |
3428 | ||
3429 | /* If not serializing, do the exec right away. Otherwise, fork down | |
3430 | into another process. */ | |
3431 | ||
3432 | if (!smtp_etrn_serialize || (pid = fork()) == 0) | |
3433 | { | |
3434 | DEBUG(D_exec) debug_print_argv(argv); | |
3435 | exim_nullstd(); /* Ensure std{in,out,err} exist */ | |
3436 | execv(CS argv[0], (char *const *)argv); | |
3437 | log_write(0, LOG_MAIN|LOG_PANIC_DIE, "exec of \"%s\" (ETRN) failed: %s", | |
3438 | etrn_command, strerror(errno)); | |
3439 | _exit(EXIT_FAILURE); /* paranoia */ | |
3440 | } | |
3441 | ||
3442 | /* Obey this if smtp_serialize and the 2nd fork yielded non-zero. That | |
3443 | is, we are in the first subprocess, after forking again. All we can do | |
3444 | for a failing fork is to log it. Otherwise, wait for the 2nd process to | |
3445 | complete, before removing the serialization. */ | |
3446 | ||
3447 | if (pid < 0) | |
3448 | log_write(0, LOG_MAIN|LOG_PANIC, "2nd fork for serialized ETRN " | |
3449 | "failed: %s", strerror(errno)); | |
3450 | else | |
3451 | { | |
3452 | int status; | |
3453 | DEBUG(D_any) debug_printf("waiting for serialized ETRN process %d\n", | |
3454 | (int)pid); | |
3455 | (void)wait(&status); | |
3456 | DEBUG(D_any) debug_printf("serialized ETRN process %d ended\n", | |
3457 | (int)pid); | |
3458 | } | |
3459 | ||
3460 | enq_end(etrn_serialize_key); | |
3461 | _exit(EXIT_SUCCESS); | |
3462 | } | |
3463 | ||
3464 | /* Back in the top level SMTP process. Check that we started a subprocess | |
3465 | and restore the signal state. */ | |
3466 | ||
3467 | if (pid < 0) | |
3468 | { | |
3469 | log_write(0, LOG_MAIN|LOG_PANIC, "fork of process for ETRN failed: %s", | |
3470 | strerror(errno)); | |
3471 | smtp_printf("458 Unable to fork process\r\n"); | |
3472 | if (smtp_etrn_serialize) enq_end(etrn_serialize_key); | |
3473 | } | |
3474 | else smtp_printf("250 OK\r\n"); | |
3475 | ||
3476 | signal(SIGCHLD, oldsignal); | |
3477 | break; | |
3478 | ||
3479 | ||
3480 | case BADARG_CMD: | |
3481 | done = synprot_error(L_smtp_syntax_error, 501, NULL, | |
3482 | US"unexpected argument data"); | |
3483 | break; | |
3484 | ||
3485 | ||
3486 | /* This currently happens only for NULLs, but could be extended. */ | |
3487 | ||
3488 | case BADCHAR_CMD: | |
3489 | done = synprot_error(L_smtp_syntax_error, 0, NULL, /* Just logs */ | |
3490 | US"NULL character(s) present (shown as '?')"); | |
3491 | smtp_printf("501 NULL characters are not allowed in SMTP commands\r\n"); | |
3492 | break; | |
3493 | ||
3494 | ||
3495 | case BADSYN_CMD: | |
3496 | if (smtp_inend >= smtp_inbuffer + in_buffer_size) | |
3497 | smtp_inend = smtp_inbuffer + in_buffer_size - 1; | |
3498 | c = smtp_inend - smtp_inptr; | |
3499 | if (c > 150) c = 150; | |
3500 | smtp_inptr[c] = 0; | |
3501 | incomplete_transaction_log(US"sync failure"); | |
3502 | log_write(0, LOG_MAIN|LOG_REJECT, "SMTP protocol violation: " | |
3503 | "synchronization error " | |
3504 | "(next input sent too soon: pipelining was%s advertised): " | |
3505 | "rejected \"%s\" %s next input=\"%s\"", | |
3506 | pipelining_advertised? "" : " not", | |
3507 | cmd_buffer, host_and_ident(TRUE), | |
3508 | string_printing(smtp_inptr)); | |
3509 | smtp_printf("554 SMTP synchronization error\r\n"); | |
3510 | done = 1; /* Pretend eof - drops connection */ | |
3511 | break; | |
3512 | ||
3513 | ||
3514 | case TOO_MANY_NONMAIL_CMD: | |
3515 | incomplete_transaction_log(US"too many non-mail commands"); | |
3516 | log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many " | |
3517 | "nonmail commands (last was \"%.*s\")", host_and_ident(FALSE), | |
3518 | smtp_data - cmd_buffer, cmd_buffer); | |
3519 | smtp_printf("554 Too many nonmail commands\r\n"); | |
3520 | done = 1; /* Pretend eof - drops connection */ | |
3521 | break; | |
3522 | ||
3523 | ||
3524 | default: | |
3525 | if (unknown_command_count++ >= smtp_max_unknown_commands) | |
3526 | { | |
3527 | log_write(L_smtp_syntax_error, LOG_MAIN, | |
3528 | "SMTP syntax error in \"%s\" %s %s", | |
3529 | string_printing(cmd_buffer), host_and_ident(TRUE), | |
3530 | US"unrecognized command"); | |
3531 | incomplete_transaction_log(US"unrecognized command"); | |
3532 | smtp_printf("500 Too many unrecognized commands\r\n"); | |
3533 | done = 2; | |
3534 | log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many " | |
3535 | "unrecognized commands (last was \"%s\")", host_and_ident(FALSE), | |
3536 | cmd_buffer); | |
3537 | } | |
3538 | else | |
3539 | done = synprot_error(L_smtp_syntax_error, 500, NULL, | |
3540 | US"unrecognized command"); | |
3541 | break; | |
3542 | } | |
3543 | ||
3544 | /* This label is used by goto's inside loops that want to break out to | |
3545 | the end of the command-processing loop. */ | |
3546 | ||
3547 | COMMAND_LOOP: | |
3548 | last_was_rej_mail = was_rej_mail; /* Remember some last commands for */ | |
3549 | last_was_rcpt = was_rcpt; /* protocol error handling */ | |
3550 | continue; | |
3551 | } | |
3552 | ||
3553 | return done - 2; /* Convert yield values */ | |
3554 | } | |
3555 | ||
3556 | /* End of smtp_in.c */ |