4267bc5f75132f8adc51b79fbc6a0e063b70acdd
[exim.git] / src / src / smtp_in.c
1 /*************************************************
2 * Exim - an Internet mail transport agent *
3 *************************************************/
4
5 /* Copyright (c) University of Cambridge 1995 - 2018 */
6 /* See the file NOTICE for conditions of use and distribution. */
7
8 /* Functions for handling an incoming SMTP call. */
9
10
11 #include "exim.h"
12 #include <assert.h>
13
14
15 /* Initialize for TCP wrappers if so configured. It appears that the macro
16 HAVE_IPV6 is used in some versions of the tcpd.h header, so we unset it before
17 including that header, and restore its value afterwards. */
18
19 #ifdef USE_TCP_WRAPPERS
20
21 #if HAVE_IPV6
22 #define EXIM_HAVE_IPV6
23 #endif
24 #undef HAVE_IPV6
25 #include <tcpd.h>
26 #undef HAVE_IPV6
27 #ifdef EXIM_HAVE_IPV6
28 #define HAVE_IPV6 TRUE
29 #endif
30
31 int allow_severity = LOG_INFO;
32 int deny_severity = LOG_NOTICE;
33 uschar *tcp_wrappers_name;
34 #endif
35
36
37 /* Size of buffer for reading SMTP commands. We used to use 512, as defined
38 by RFC 821. However, RFC 1869 specifies that this must be increased for SMTP
39 commands that accept arguments, and this in particular applies to AUTH, where
40 the data can be quite long. More recently this value was 2048 in Exim;
41 however, RFC 4954 (circa 2007) recommends 12288 bytes to handle AUTH. Clients
42 such as Thunderbird will send an AUTH with an initial-response for GSSAPI.
43 The maximum size of a Kerberos ticket under Windows 2003 is 12000 bytes, and
44 we need room to handle large base64-encoded AUTHs for GSSAPI.
45 */
46
47 #define SMTP_CMD_BUFFER_SIZE 16384
48
49 /* Size of buffer for reading SMTP incoming packets */
50
51 #define IN_BUFFER_SIZE 8192
52
53 /* Structure for SMTP command list */
54
55 typedef struct {
56 const char *name;
57 int len;
58 short int cmd;
59 short int has_arg;
60 short int is_mail_cmd;
61 } smtp_cmd_list;
62
63 /* Codes for identifying commands. We order them so that those that come first
64 are those for which synchronization is always required. Checking this can help
65 block some spam. */
66
67 enum {
68 /* These commands are required to be synchronized, i.e. to be the last in a
69 block of commands when pipelining. */
70
71 HELO_CMD, EHLO_CMD, DATA_CMD, /* These are listed in the pipelining */
72 VRFY_CMD, EXPN_CMD, NOOP_CMD, /* RFC as requiring synchronization */
73 ETRN_CMD, /* This by analogy with TURN from the RFC */
74 STARTTLS_CMD, /* Required by the STARTTLS RFC */
75 TLS_AUTH_CMD, /* auto-command at start of SSL */
76
77 /* This is a dummy to identify the non-sync commands when pipelining */
78
79 NON_SYNC_CMD_PIPELINING,
80
81 /* These commands need not be synchronized when pipelining */
82
83 MAIL_CMD, RCPT_CMD, RSET_CMD,
84
85 /* This is a dummy to identify the non-sync commands when not pipelining */
86
87 NON_SYNC_CMD_NON_PIPELINING,
88
89 /* RFC3030 section 2: "After all MAIL and RCPT responses are collected and
90 processed the message is sent using a series of BDAT commands"
91 implies that BDAT should be synchronized. However, we see Google, at least,
92 sending MAIL,RCPT,BDAT-LAST in a single packet, clearly not waiting for
93 processing of the RCPT response(s). We shall do the same, and not require
94 synch for BDAT. Worse, as the chunk may (very likely will) follow the
95 command-header in the same packet we cannot do the usual "is there any
96 follow-on data after the command line" even for non-pipeline mode.
97 So we'll need an explicit check after reading the expected chunk amount
98 when non-pipe, before sending the ACK. */
99
100 BDAT_CMD,
101
102 /* I have been unable to find a statement about the use of pipelining
103 with AUTH, so to be on the safe side it is here, though I kind of feel
104 it should be up there with the synchronized commands. */
105
106 AUTH_CMD,
107
108 /* I'm not sure about these, but I don't think they matter. */
109
110 QUIT_CMD, HELP_CMD,
111
112 #ifdef SUPPORT_PROXY
113 PROXY_FAIL_IGNORE_CMD,
114 #endif
115
116 /* These are specials that don't correspond to actual commands */
117
118 EOF_CMD, OTHER_CMD, BADARG_CMD, BADCHAR_CMD, BADSYN_CMD,
119 TOO_MANY_NONMAIL_CMD };
120
121
122 /* This is a convenience macro for adding the identity of an SMTP command
123 to the circular buffer that holds a list of the last n received. */
124
125 #define HAD(n) \
126 smtp_connection_had[smtp_ch_index++] = n; \
127 if (smtp_ch_index >= SMTP_HBUFF_SIZE) smtp_ch_index = 0
128
129
130 /*************************************************
131 * Local static variables *
132 *************************************************/
133
134 static auth_instance *authenticated_by;
135 static BOOL auth_advertised;
136 #ifdef SUPPORT_TLS
137 static BOOL tls_advertised;
138 # ifdef EXPERIMENTAL_REQUIRETLS
139 static BOOL requiretls_advertised;
140 # endif
141 #endif
142 static BOOL dsn_advertised;
143 static BOOL esmtp;
144 static BOOL helo_required = FALSE;
145 static BOOL helo_verify = FALSE;
146 static BOOL helo_seen;
147 static BOOL helo_accept_junk;
148 static BOOL count_nonmail;
149 static BOOL rcpt_smtp_response_same;
150 static BOOL rcpt_in_progress;
151 static int nonmail_command_count;
152 static BOOL smtp_exit_function_called = 0;
153 #ifdef SUPPORT_I18N
154 static BOOL smtputf8_advertised;
155 #endif
156 static int synprot_error_count;
157 static int unknown_command_count;
158 static int sync_cmd_limit;
159 static int smtp_write_error = 0;
160
161 static uschar *rcpt_smtp_response;
162 static uschar *smtp_data_buffer;
163 static uschar *smtp_cmd_data;
164
165 /* We need to know the position of RSET, HELO, EHLO, AUTH, and STARTTLS. Their
166 final fields of all except AUTH are forced TRUE at the start of a new message
167 setup, to allow one of each between messages that is not counted as a nonmail
168 command. (In fact, only one of HELO/EHLO is not counted.) Also, we have to
169 allow a new EHLO after starting up TLS.
170
171 AUTH is "falsely" labelled as a mail command initially, so that it doesn't get
172 counted. However, the flag is changed when AUTH is received, so that multiple
173 failing AUTHs will eventually hit the limit. After a successful AUTH, another
174 AUTH is already forbidden. After a TLS session is started, AUTH's flag is again
175 forced TRUE, to allow for the re-authentication that can happen at that point.
176
177 QUIT is also "falsely" labelled as a mail command so that it doesn't up the
178 count of non-mail commands and possibly provoke an error.
179
180 tls_auth is a pseudo-command, never expected in input. It is activated
181 on TLS startup and looks for a tls authenticator. */
182
183 static smtp_cmd_list cmd_list[] = {
184 /* name len cmd has_arg is_mail_cmd */
185
186 { "rset", sizeof("rset")-1, RSET_CMD, FALSE, FALSE }, /* First */
187 { "helo", sizeof("helo")-1, HELO_CMD, TRUE, FALSE },
188 { "ehlo", sizeof("ehlo")-1, EHLO_CMD, TRUE, FALSE },
189 { "auth", sizeof("auth")-1, AUTH_CMD, TRUE, TRUE },
190 #ifdef SUPPORT_TLS
191 { "starttls", sizeof("starttls")-1, STARTTLS_CMD, FALSE, FALSE },
192 { "tls_auth", 0, TLS_AUTH_CMD, FALSE, FALSE },
193 #endif
194
195 /* If you change anything above here, also fix the definitions below. */
196
197 { "mail from:", sizeof("mail from:")-1, MAIL_CMD, TRUE, TRUE },
198 { "rcpt to:", sizeof("rcpt to:")-1, RCPT_CMD, TRUE, TRUE },
199 { "data", sizeof("data")-1, DATA_CMD, FALSE, TRUE },
200 { "bdat", sizeof("bdat")-1, BDAT_CMD, TRUE, TRUE },
201 { "quit", sizeof("quit")-1, QUIT_CMD, FALSE, TRUE },
202 { "noop", sizeof("noop")-1, NOOP_CMD, TRUE, FALSE },
203 { "etrn", sizeof("etrn")-1, ETRN_CMD, TRUE, FALSE },
204 { "vrfy", sizeof("vrfy")-1, VRFY_CMD, TRUE, FALSE },
205 { "expn", sizeof("expn")-1, EXPN_CMD, TRUE, FALSE },
206 { "help", sizeof("help")-1, HELP_CMD, TRUE, FALSE }
207 };
208
209 static smtp_cmd_list *cmd_list_end =
210 cmd_list + sizeof(cmd_list)/sizeof(smtp_cmd_list);
211
212 #define CMD_LIST_RSET 0
213 #define CMD_LIST_HELO 1
214 #define CMD_LIST_EHLO 2
215 #define CMD_LIST_AUTH 3
216 #define CMD_LIST_STARTTLS 4
217 #define CMD_LIST_TLS_AUTH 5
218
219 /* This list of names is used for performing the smtp_no_mail logging action.
220 It must be kept in step with the SCH_xxx enumerations. */
221
222 static uschar *smtp_names[] =
223 {
224 US"NONE", US"AUTH", US"DATA", US"BDAT", US"EHLO", US"ETRN", US"EXPN",
225 US"HELO", US"HELP", US"MAIL", US"NOOP", US"QUIT", US"RCPT", US"RSET",
226 US"STARTTLS", US"VRFY" };
227
228 static uschar *protocols_local[] = {
229 US"local-smtp", /* HELO */
230 US"local-smtps", /* The rare case EHLO->STARTTLS->HELO */
231 US"local-esmtp", /* EHLO */
232 US"local-esmtps", /* EHLO->STARTTLS->EHLO */
233 US"local-esmtpa", /* EHLO->AUTH */
234 US"local-esmtpsa" /* EHLO->STARTTLS->EHLO->AUTH */
235 };
236 static uschar *protocols[] = {
237 US"smtp", /* HELO */
238 US"smtps", /* The rare case EHLO->STARTTLS->HELO */
239 US"esmtp", /* EHLO */
240 US"esmtps", /* EHLO->STARTTLS->EHLO */
241 US"esmtpa", /* EHLO->AUTH */
242 US"esmtpsa" /* EHLO->STARTTLS->EHLO->AUTH */
243 };
244
245 #define pnormal 0
246 #define pextend 2
247 #define pcrpted 1 /* added to pextend or pnormal */
248 #define pauthed 2 /* added to pextend */
249
250 /* Sanity check and validate optional args to MAIL FROM: envelope */
251 enum {
252 ENV_MAIL_OPT_NULL,
253 ENV_MAIL_OPT_SIZE, ENV_MAIL_OPT_BODY, ENV_MAIL_OPT_AUTH,
254 #ifndef DISABLE_PRDR
255 ENV_MAIL_OPT_PRDR,
256 #endif
257 ENV_MAIL_OPT_RET, ENV_MAIL_OPT_ENVID,
258 #ifdef SUPPORT_I18N
259 ENV_MAIL_OPT_UTF8,
260 #endif
261 #ifdef EXPERIMENTAL_REQUIRETLS
262 ENV_MAIL_OPT_REQTLS,
263 #endif
264 };
265 typedef struct {
266 uschar * name; /* option requested during MAIL cmd */
267 int value; /* enum type */
268 BOOL need_value; /* TRUE requires value (name=value pair format)
269 FALSE is a singleton */
270 } env_mail_type_t;
271 static env_mail_type_t env_mail_type_list[] = {
272 { US"SIZE", ENV_MAIL_OPT_SIZE, TRUE },
273 { US"BODY", ENV_MAIL_OPT_BODY, TRUE },
274 { US"AUTH", ENV_MAIL_OPT_AUTH, TRUE },
275 #ifndef DISABLE_PRDR
276 { US"PRDR", ENV_MAIL_OPT_PRDR, FALSE },
277 #endif
278 { US"RET", ENV_MAIL_OPT_RET, TRUE },
279 { US"ENVID", ENV_MAIL_OPT_ENVID, TRUE },
280 #ifdef SUPPORT_I18N
281 { US"SMTPUTF8",ENV_MAIL_OPT_UTF8, FALSE }, /* rfc6531 */
282 #endif
283 #ifdef EXPERIMENTAL_REQUIRETLS
284 /* https://tools.ietf.org/html/draft-ietf-uta-smtp-require-tls-03 */
285 { US"REQUIRETLS",ENV_MAIL_OPT_REQTLS, FALSE },
286 #endif
287 /* keep this the last entry */
288 { US"NULL", ENV_MAIL_OPT_NULL, FALSE },
289 };
290
291 /* When reading SMTP from a remote host, we have to use our own versions of the
292 C input-reading functions, in order to be able to flush the SMTP output only
293 when about to read more data from the socket. This is the only way to get
294 optimal performance when the client is using pipelining. Flushing for every
295 command causes a separate packet and reply packet each time; saving all the
296 responses up (when pipelining) combines them into one packet and one response.
297
298 For simplicity, these functions are used for *all* SMTP input, not only when
299 receiving over a socket. However, after setting up a secure socket (SSL), input
300 is read via the OpenSSL library, and another set of functions is used instead
301 (see tls.c).
302
303 These functions are set in the receive_getc etc. variables and called with the
304 same interface as the C functions. However, since there can only ever be
305 one incoming SMTP call, we just use a single buffer and flags. There is no need
306 to implement a complicated private FILE-like structure.*/
307
308 static uschar *smtp_inbuffer;
309 static uschar *smtp_inptr;
310 static uschar *smtp_inend;
311 static int smtp_had_eof;
312 static int smtp_had_error;
313
314
315 /* forward declarations */
316 static int smtp_read_command(BOOL check_sync, unsigned buffer_lim);
317 static int synprot_error(int type, int code, uschar *data, uschar *errmess);
318 static void smtp_quit_handler(uschar **, uschar **);
319 static void smtp_rset_handler(void);
320
321 /*************************************************
322 * Recheck synchronization *
323 *************************************************/
324
325 /* Synchronization checks can never be perfect because a packet may be on its
326 way but not arrived when the check is done. Normally, the checks happen when
327 commands are read: Exim ensures that there is no more input in the input buffer.
328 In normal cases, the response to the command will be fast, and there is no
329 further check.
330
331 However, for some commands an ACL is run, and that can include delays. In those
332 cases, it is useful to do another check on the input just before sending the
333 response. This also applies at the start of a connection. This function does
334 that check by means of the select() function, as long as the facility is not
335 disabled or inappropriate. A failure of select() is ignored.
336
337 When there is unwanted input, we read it so that it appears in the log of the
338 error.
339
340 Arguments: none
341 Returns: TRUE if all is well; FALSE if there is input pending
342 */
343
344 static BOOL
345 wouldblock_reading(void)
346 {
347 int fd, rc;
348 fd_set fds;
349 struct timeval tzero;
350
351 #ifdef SUPPORT_TLS
352 if (tls_in.active.sock >= 0)
353 return !tls_could_read();
354 #endif
355
356 if (smtp_inptr < smtp_inend)
357 return FALSE;
358
359 fd = fileno(smtp_in);
360 FD_ZERO(&fds);
361 FD_SET(fd, &fds);
362 tzero.tv_sec = 0;
363 tzero.tv_usec = 0;
364 rc = select(fd + 1, (SELECT_ARG2_TYPE *)&fds, NULL, NULL, &tzero);
365
366 if (rc <= 0) return TRUE; /* Not ready to read */
367 rc = smtp_getc(GETC_BUFFER_UNLIMITED);
368 if (rc < 0) return TRUE; /* End of file or error */
369
370 smtp_ungetc(rc);
371 return FALSE;
372 }
373
374 static BOOL
375 check_sync(void)
376 {
377 if (!smtp_enforce_sync || !sender_host_address || f.sender_host_notsocket)
378 return TRUE;
379
380 return wouldblock_reading();
381 }
382
383
384 /* If there's input waiting (and we're doing pipelineing) then we can pipeline
385 a reponse with the one following. */
386
387 static BOOL
388 pipeline_response(void)
389 {
390 if ( !smtp_enforce_sync || !sender_host_address
391 || f.sender_host_notsocket || !f.smtp_in_pipelining_advertised)
392 return FALSE;
393
394 if (wouldblock_reading()) return FALSE;
395 f.smtp_in_pipelining_used = TRUE;
396 return TRUE;
397 }
398
399
400
401 /*************************************************
402 * Log incomplete transactions *
403 *************************************************/
404
405 /* This function is called after a transaction has been aborted by RSET, QUIT,
406 connection drops or other errors. It logs the envelope information received
407 so far in order to preserve address verification attempts.
408
409 Argument: string to indicate what aborted the transaction
410 Returns: nothing
411 */
412
413 static void
414 incomplete_transaction_log(uschar *what)
415 {
416 if (sender_address == NULL || /* No transaction in progress */
417 !LOGGING(smtp_incomplete_transaction))
418 return;
419
420 /* Build list of recipients for logging */
421
422 if (recipients_count > 0)
423 {
424 int i;
425 raw_recipients = store_get(recipients_count * sizeof(uschar *));
426 for (i = 0; i < recipients_count; i++)
427 raw_recipients[i] = recipients_list[i].address;
428 raw_recipients_count = recipients_count;
429 }
430
431 log_write(L_smtp_incomplete_transaction, LOG_MAIN|LOG_SENDER|LOG_RECIPIENTS,
432 "%s incomplete transaction (%s)", host_and_ident(TRUE), what);
433 }
434
435
436
437
438 void
439 smtp_command_timeout_exit(void)
440 {
441 log_write(L_lost_incoming_connection,
442 LOG_MAIN, "SMTP command timeout on%s connection from %s",
443 tls_in.active.sock >= 0 ? " TLS" : "", host_and_ident(FALSE));
444 if (smtp_batched_input)
445 moan_smtp_batch(NULL, "421 SMTP command timeout"); /* Does not return */
446 smtp_notquit_exit(US"command-timeout", US"421",
447 US"%s: SMTP command timeout - closing connection",
448 smtp_active_hostname);
449 exim_exit(EXIT_FAILURE, US"receiving");
450 }
451
452 void
453 smtp_command_sigterm_exit(void)
454 {
455 log_write(0, LOG_MAIN, "%s closed after SIGTERM", smtp_get_connection_info());
456 if (smtp_batched_input)
457 moan_smtp_batch(NULL, "421 SIGTERM received"); /* Does not return */
458 smtp_notquit_exit(US"signal-exit", US"421",
459 US"%s: Service not available - closing connection", smtp_active_hostname);
460 exim_exit(EXIT_FAILURE, US"receiving");
461 }
462
463 void
464 smtp_data_timeout_exit(void)
465 {
466 log_write(L_lost_incoming_connection,
467 LOG_MAIN, "SMTP data timeout (message abandoned) on connection from %s F=<%s>",
468 sender_fullhost ? sender_fullhost : US"local process", sender_address);
469 receive_bomb_out(US"data-timeout", US"SMTP incoming data timeout");
470 /* Does not return */
471 }
472
473 void
474 smtp_data_sigint_exit(void)
475 {
476 log_write(0, LOG_MAIN, "%s closed after %s",
477 smtp_get_connection_info(), had_data_sigint == SIGTERM ? "SIGTERM":"SIGINT");
478 receive_bomb_out(US"signal-exit",
479 US"Service not available - SIGTERM or SIGINT received");
480 /* Does not return */
481 }
482
483
484
485 /* Refill the buffer, and notify DKIM verification code.
486 Return false for error or EOF.
487 */
488
489 static BOOL
490 smtp_refill(unsigned lim)
491 {
492 int rc, save_errno;
493 if (!smtp_out) return FALSE;
494 fflush(smtp_out);
495 if (smtp_receive_timeout > 0) alarm(smtp_receive_timeout);
496
497 /* Limit amount read, so non-message data is not fed to DKIM.
498 Take care to not touch the safety NUL at the end of the buffer. */
499
500 rc = read(fileno(smtp_in), smtp_inbuffer, MIN(IN_BUFFER_SIZE-1, lim));
501 save_errno = errno;
502 if (smtp_receive_timeout > 0) alarm(0);
503 if (rc <= 0)
504 {
505 /* Must put the error text in fixed store, because this might be during
506 header reading, where it releases unused store above the header. */
507 if (rc < 0)
508 {
509 if (had_command_timeout) /* set by signal handler */
510 smtp_command_timeout_exit(); /* does not return */
511 if (had_command_sigterm)
512 smtp_command_sigterm_exit();
513 if (had_data_timeout)
514 smtp_data_timeout_exit();
515 if (had_data_sigint)
516 smtp_data_sigint_exit();
517
518 smtp_had_error = save_errno;
519 smtp_read_error = string_copy_malloc(
520 string_sprintf(" (error: %s)", strerror(save_errno)));
521 }
522 else
523 smtp_had_eof = 1;
524 return FALSE;
525 }
526 #ifndef DISABLE_DKIM
527 dkim_exim_verify_feed(smtp_inbuffer, rc);
528 #endif
529 smtp_inend = smtp_inbuffer + rc;
530 smtp_inptr = smtp_inbuffer;
531 return TRUE;
532 }
533
534 /*************************************************
535 * SMTP version of getc() *
536 *************************************************/
537
538 /* This gets the next byte from the SMTP input buffer. If the buffer is empty,
539 it flushes the output, and refills the buffer, with a timeout. The signal
540 handler is set appropriately by the calling function. This function is not used
541 after a connection has negotiated itself into an TLS/SSL state.
542
543 Arguments: lim Maximum amount to read/buffer
544 Returns: the next character or EOF
545 */
546
547 int
548 smtp_getc(unsigned lim)
549 {
550 if (smtp_inptr >= smtp_inend)
551 if (!smtp_refill(lim))
552 return EOF;
553 return *smtp_inptr++;
554 }
555
556 uschar *
557 smtp_getbuf(unsigned * len)
558 {
559 unsigned size;
560 uschar * buf;
561
562 if (smtp_inptr >= smtp_inend)
563 if (!smtp_refill(*len))
564 { *len = 0; return NULL; }
565
566 if ((size = smtp_inend - smtp_inptr) > *len) size = *len;
567 buf = smtp_inptr;
568 smtp_inptr += size;
569 *len = size;
570 return buf;
571 }
572
573 void
574 smtp_get_cache(void)
575 {
576 #ifndef DISABLE_DKIM
577 int n = smtp_inend - smtp_inptr;
578 if (n > 0)
579 dkim_exim_verify_feed(smtp_inptr, n);
580 #endif
581 }
582
583
584 /* Get a byte from the smtp input, in CHUNKING mode. Handle ack of the
585 previous BDAT chunk and getting new ones when we run out. Uses the
586 underlying smtp_getc or tls_getc both for that and for getting the
587 (buffered) data byte. EOD signals (an expected) no further data.
588 ERR signals a protocol error, and EOF a closed input stream.
589
590 Called from read_bdat_smtp() in receive.c for the message body, but also
591 by the headers read loop in receive_msg(); manipulates chunking_state
592 to handle the BDAT command/response.
593 Placed here due to the correlation with the above smtp_getc(), which it wraps,
594 and also by the need to do smtp command/response handling.
595
596 Arguments: lim (ignored)
597 Returns: the next character or ERR, EOD or EOF
598 */
599
600 int
601 bdat_getc(unsigned lim)
602 {
603 uschar * user_msg = NULL;
604 uschar * log_msg;
605
606 for(;;)
607 {
608 #ifndef DISABLE_DKIM
609 unsigned dkim_save;
610 #endif
611
612 if (chunking_data_left > 0)
613 return lwr_receive_getc(chunking_data_left--);
614
615 receive_getc = lwr_receive_getc;
616 receive_getbuf = lwr_receive_getbuf;
617 receive_ungetc = lwr_receive_ungetc;
618 #ifndef DISABLE_DKIM
619 dkim_save = dkim_collect_input;
620 dkim_collect_input = 0;
621 #endif
622
623 /* Unless PIPELINING was offered, there should be no next command
624 until after we ack that chunk */
625
626 if (!f.smtp_in_pipelining_advertised && !check_sync())
627 {
628 unsigned n = smtp_inend - smtp_inptr;
629 if (n > 32) n = 32;
630
631 incomplete_transaction_log(US"sync failure");
632 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP protocol synchronization error "
633 "(next input sent too soon: pipelining was not advertised): "
634 "rejected \"%s\" %s next input=\"%s\"%s",
635 smtp_cmd_buffer, host_and_ident(TRUE),
636 string_printing(string_copyn(smtp_inptr, n)),
637 smtp_inend - smtp_inptr > n ? "..." : "");
638 (void) synprot_error(L_smtp_protocol_error, 554, NULL,
639 US"SMTP synchronization error");
640 goto repeat_until_rset;
641 }
642
643 /* If not the last, ack the received chunk. The last response is delayed
644 until after the data ACL decides on it */
645
646 if (chunking_state == CHUNKING_LAST)
647 {
648 #ifndef DISABLE_DKIM
649 dkim_exim_verify_feed(NULL, 0); /* notify EOD */
650 #endif
651 return EOD;
652 }
653
654 smtp_printf("250 %u byte chunk received\r\n", FALSE, chunking_datasize);
655 chunking_state = CHUNKING_OFFERED;
656 DEBUG(D_receive) debug_printf("chunking state %d\n", (int)chunking_state);
657
658 /* Expect another BDAT cmd from input. RFC 3030 says nothing about
659 QUIT, RSET or NOOP but handling them seems obvious */
660
661 next_cmd:
662 switch(smtp_read_command(TRUE, 1))
663 {
664 default:
665 (void) synprot_error(L_smtp_protocol_error, 503, NULL,
666 US"only BDAT permissible after non-LAST BDAT");
667
668 repeat_until_rset:
669 switch(smtp_read_command(TRUE, 1))
670 {
671 case QUIT_CMD: smtp_quit_handler(&user_msg, &log_msg); /*FALLTHROUGH */
672 case EOF_CMD: return EOF;
673 case RSET_CMD: smtp_rset_handler(); return ERR;
674 default: if (synprot_error(L_smtp_protocol_error, 503, NULL,
675 US"only RSET accepted now") > 0)
676 return EOF;
677 goto repeat_until_rset;
678 }
679
680 case QUIT_CMD:
681 smtp_quit_handler(&user_msg, &log_msg);
682 /*FALLTHROUGH*/
683 case EOF_CMD:
684 return EOF;
685
686 case RSET_CMD:
687 smtp_rset_handler();
688 return ERR;
689
690 case NOOP_CMD:
691 HAD(SCH_NOOP);
692 smtp_printf("250 OK\r\n", FALSE);
693 goto next_cmd;
694
695 case BDAT_CMD:
696 {
697 int n;
698
699 if (sscanf(CS smtp_cmd_data, "%u %n", &chunking_datasize, &n) < 1)
700 {
701 (void) synprot_error(L_smtp_protocol_error, 501, NULL,
702 US"missing size for BDAT command");
703 return ERR;
704 }
705 chunking_state = strcmpic(smtp_cmd_data+n, US"LAST") == 0
706 ? CHUNKING_LAST : CHUNKING_ACTIVE;
707 chunking_data_left = chunking_datasize;
708 DEBUG(D_receive) debug_printf("chunking state %d, %d bytes\n",
709 (int)chunking_state, chunking_data_left);
710
711 if (chunking_datasize == 0)
712 if (chunking_state == CHUNKING_LAST)
713 return EOD;
714 else
715 {
716 (void) synprot_error(L_smtp_protocol_error, 504, NULL,
717 US"zero size for BDAT command");
718 goto repeat_until_rset;
719 }
720
721 receive_getc = bdat_getc;
722 receive_getbuf = bdat_getbuf; /* r~getbuf is never actually used */
723 receive_ungetc = bdat_ungetc;
724 #ifndef DISABLE_DKIM
725 dkim_collect_input = dkim_save;
726 #endif
727 break; /* to top of main loop */
728 }
729 }
730 }
731 }
732
733 uschar *
734 bdat_getbuf(unsigned * len)
735 {
736 uschar * buf;
737
738 if (chunking_data_left <= 0)
739 { *len = 0; return NULL; }
740
741 if (*len > chunking_data_left) *len = chunking_data_left;
742 buf = lwr_receive_getbuf(len); /* Either smtp_getbuf or tls_getbuf */
743 chunking_data_left -= *len;
744 return buf;
745 }
746
747 void
748 bdat_flush_data(void)
749 {
750 while (chunking_data_left)
751 {
752 unsigned n = chunking_data_left;
753 if (!bdat_getbuf(&n)) break;
754 }
755
756 receive_getc = lwr_receive_getc;
757 receive_getbuf = lwr_receive_getbuf;
758 receive_ungetc = lwr_receive_ungetc;
759
760 if (chunking_state != CHUNKING_LAST)
761 {
762 chunking_state = CHUNKING_OFFERED;
763 DEBUG(D_receive) debug_printf("chunking state %d\n", (int)chunking_state);
764 }
765 }
766
767
768
769
770 /*************************************************
771 * SMTP version of ungetc() *
772 *************************************************/
773
774 /* Puts a character back in the input buffer. Only ever
775 called once.
776
777 Arguments:
778 ch the character
779
780 Returns: the character
781 */
782
783 int
784 smtp_ungetc(int ch)
785 {
786 *--smtp_inptr = ch;
787 return ch;
788 }
789
790
791 int
792 bdat_ungetc(int ch)
793 {
794 chunking_data_left++;
795 return lwr_receive_ungetc(ch);
796 }
797
798
799
800 /*************************************************
801 * SMTP version of feof() *
802 *************************************************/
803
804 /* Tests for a previous EOF
805
806 Arguments: none
807 Returns: non-zero if the eof flag is set
808 */
809
810 int
811 smtp_feof(void)
812 {
813 return smtp_had_eof;
814 }
815
816
817
818
819 /*************************************************
820 * SMTP version of ferror() *
821 *************************************************/
822
823 /* Tests for a previous read error, and returns with errno
824 restored to what it was when the error was detected.
825
826 Arguments: none
827 Returns: non-zero if the error flag is set
828 */
829
830 int
831 smtp_ferror(void)
832 {
833 errno = smtp_had_error;
834 return smtp_had_error;
835 }
836
837
838
839 /*************************************************
840 * Test for characters in the SMTP buffer *
841 *************************************************/
842
843 /* Used at the end of a message
844
845 Arguments: none
846 Returns: TRUE/FALSE
847 */
848
849 BOOL
850 smtp_buffered(void)
851 {
852 return smtp_inptr < smtp_inend;
853 }
854
855
856
857 /*************************************************
858 * Write formatted string to SMTP channel *
859 *************************************************/
860
861 /* This is a separate function so that we don't have to repeat everything for
862 TLS support or debugging. It is global so that the daemon and the
863 authentication functions can use it. It does not return any error indication,
864 because major problems such as dropped connections won't show up till an output
865 flush for non-TLS connections. The smtp_fflush() function is available for
866 checking that: for convenience, TLS output errors are remembered here so that
867 they are also picked up later by smtp_fflush().
868
869 Arguments:
870 format format string
871 more further data expected
872 ... optional arguments
873
874 Returns: nothing
875 */
876
877 void
878 smtp_printf(const char *format, BOOL more, ...)
879 {
880 va_list ap;
881
882 va_start(ap, more);
883 smtp_vprintf(format, more, ap);
884 va_end(ap);
885 }
886
887 /* This is split off so that verify.c:respond_printf() can, in effect, call
888 smtp_printf(), bearing in mind that in C a vararg function can't directly
889 call another vararg function, only a function which accepts a va_list. */
890
891 void
892 smtp_vprintf(const char *format, BOOL more, va_list ap)
893 {
894 BOOL yield;
895
896 yield = string_vformat(big_buffer, big_buffer_size, format, ap);
897
898 DEBUG(D_receive)
899 {
900 void *reset_point = store_get(0);
901 uschar *msg_copy, *cr, *end;
902 msg_copy = string_copy(big_buffer);
903 end = msg_copy + Ustrlen(msg_copy);
904 while ((cr = Ustrchr(msg_copy, '\r')) != NULL) /* lose CRs */
905 memmove(cr, cr + 1, (end--) - cr);
906 debug_printf("SMTP>> %s", msg_copy);
907 store_reset(reset_point);
908 }
909
910 if (!yield)
911 {
912 log_write(0, LOG_MAIN|LOG_PANIC, "string too large in smtp_printf()");
913 smtp_closedown(US"Unexpected error");
914 exim_exit(EXIT_FAILURE, NULL);
915 }
916
917 /* If this is the first output for a (non-batch) RCPT command, see if all RCPTs
918 have had the same. Note: this code is also present in smtp_respond(). It would
919 be tidier to have it only in one place, but when it was added, it was easier to
920 do it that way, so as not to have to mess with the code for the RCPT command,
921 which sometimes uses smtp_printf() and sometimes smtp_respond(). */
922
923 if (rcpt_in_progress)
924 {
925 if (rcpt_smtp_response == NULL)
926 rcpt_smtp_response = string_copy(big_buffer);
927 else if (rcpt_smtp_response_same &&
928 Ustrcmp(rcpt_smtp_response, big_buffer) != 0)
929 rcpt_smtp_response_same = FALSE;
930 rcpt_in_progress = FALSE;
931 }
932
933 /* Now write the string */
934
935 #ifdef SUPPORT_TLS
936 if (tls_in.active.sock >= 0)
937 {
938 if (tls_write(NULL, big_buffer, Ustrlen(big_buffer), more) < 0)
939 smtp_write_error = -1;
940 }
941 else
942 #endif
943
944 if (fprintf(smtp_out, "%s", big_buffer) < 0) smtp_write_error = -1;
945 }
946
947
948
949 /*************************************************
950 * Flush SMTP out and check for error *
951 *************************************************/
952
953 /* This function isn't currently used within Exim (it detects errors when it
954 tries to read the next SMTP input), but is available for use in local_scan().
955 For non-TLS connections, it flushes the output and checks for errors. For
956 TLS-connections, it checks for a previously-detected TLS write error.
957
958 Arguments: none
959 Returns: 0 for no error; -1 after an error
960 */
961
962 int
963 smtp_fflush(void)
964 {
965 if (tls_in.active.sock < 0 && fflush(smtp_out) != 0) smtp_write_error = -1;
966 return smtp_write_error;
967 }
968
969
970
971 /*************************************************
972 * SMTP command read timeout *
973 *************************************************/
974
975 /* Signal handler for timing out incoming SMTP commands. This attempts to
976 finish off tidily.
977
978 Argument: signal number (SIGALRM)
979 Returns: nothing
980 */
981
982 static void
983 command_timeout_handler(int sig)
984 {
985 had_command_timeout = sig;
986 }
987
988
989
990 /*************************************************
991 * SIGTERM received *
992 *************************************************/
993
994 /* Signal handler for handling SIGTERM. Again, try to finish tidily.
995
996 Argument: signal number (SIGTERM)
997 Returns: nothing
998 */
999
1000 static void
1001 command_sigterm_handler(int sig)
1002 {
1003 had_command_sigterm = sig;
1004 }
1005
1006
1007
1008
1009 #ifdef SUPPORT_PROXY
1010 /*************************************************
1011 * Restore socket timeout to previous value *
1012 *************************************************/
1013 /* If the previous value was successfully retrieved, restore
1014 it before returning control to the non-proxy routines
1015
1016 Arguments: fd - File descriptor for input
1017 get_ok - Successfully retrieved previous values
1018 tvtmp - Time struct with previous values
1019 vslen - Length of time struct
1020 Returns: none
1021 */
1022 static void
1023 restore_socket_timeout(int fd, int get_ok, struct timeval * tvtmp, socklen_t vslen)
1024 {
1025 if (get_ok == 0)
1026 (void) setsockopt(fd, SOL_SOCKET, SO_RCVTIMEO, CS tvtmp, vslen);
1027 }
1028
1029 /*************************************************
1030 * Check if host is required proxy host *
1031 *************************************************/
1032 /* The function determines if inbound host will be a regular smtp host
1033 or if it is configured that it must use Proxy Protocol. A local
1034 connection cannot.
1035
1036 Arguments: none
1037 Returns: bool
1038 */
1039
1040 static BOOL
1041 check_proxy_protocol_host()
1042 {
1043 int rc;
1044
1045 if ( sender_host_address
1046 && (rc = verify_check_this_host(CUSS &hosts_proxy, NULL, NULL,
1047 sender_host_address, NULL)) == OK)
1048 {
1049 DEBUG(D_receive)
1050 debug_printf("Detected proxy protocol configured host\n");
1051 proxy_session = TRUE;
1052 }
1053 return proxy_session;
1054 }
1055
1056
1057 /*************************************************
1058 * Read data until newline or end of buffer *
1059 *************************************************/
1060 /* While SMTP is server-speaks-first, TLS is client-speaks-first, so we can't
1061 read an entire buffer and assume there will be nothing past a proxy protocol
1062 header. Our approach normally is to use stdio, but again that relies upon
1063 "STARTTLS\r\n" and a server response before the client starts TLS handshake, or
1064 reading _nothing_ before client TLS handshake. So we don't want to use the
1065 usual buffering reads which may read enough to block TLS starting.
1066
1067 So unfortunately we're down to "read one byte at a time, with a syscall each,
1068 and expect a little overhead", for all proxy-opened connections which are v1,
1069 just to handle the TLS-on-connect case. Since SSL functions wrap the
1070 underlying fd, we can't assume that we can feed them any already-read content.
1071
1072 We need to know where to read to, the max capacity, and we'll read until we
1073 get a CR and one more character. Let the caller scream if it's CR+!LF.
1074
1075 Return the amount read.
1076 */
1077
1078 static int
1079 swallow_until_crlf(int fd, uschar *base, int already, int capacity)
1080 {
1081 uschar *to = base + already;
1082 uschar *cr;
1083 int have = 0;
1084 int ret;
1085 int last = 0;
1086
1087 /* For "PROXY UNKNOWN\r\n" we, at time of writing, expect to have read
1088 up through the \r; for the _normal_ case, we haven't yet seen the \r. */
1089
1090 cr = memchr(base, '\r', already);
1091 if (cr != NULL)
1092 {
1093 if ((cr - base) < already - 1)
1094 {
1095 /* \r and presumed \n already within what we have; probably not
1096 actually proxy protocol, but abort cleanly. */
1097 return 0;
1098 }
1099 /* \r is last character read, just need one more. */
1100 last = 1;
1101 }
1102
1103 while (capacity > 0)
1104 {
1105 do { ret = recv(fd, to, 1, 0); } while (ret == -1 && errno == EINTR);
1106 if (ret == -1)
1107 return -1;
1108 have++;
1109 if (last)
1110 return have;
1111 if (*to == '\r')
1112 last = 1;
1113 capacity--;
1114 to++;
1115 }
1116
1117 /* reached end without having room for a final newline, abort */
1118 errno = EOVERFLOW;
1119 return -1;
1120 }
1121
1122 /*************************************************
1123 * Setup host for proxy protocol *
1124 *************************************************/
1125 /* The function configures the connection based on a header from the
1126 inbound host to use Proxy Protocol. The specification is very exact
1127 so exit with an error if do not find the exact required pieces. This
1128 includes an incorrect number of spaces separating args.
1129
1130 Arguments: none
1131 Returns: Boolean success
1132 */
1133
1134 static void
1135 setup_proxy_protocol_host()
1136 {
1137 union {
1138 struct {
1139 uschar line[108];
1140 } v1;
1141 struct {
1142 uschar sig[12];
1143 uint8_t ver_cmd;
1144 uint8_t fam;
1145 uint16_t len;
1146 union {
1147 struct { /* TCP/UDP over IPv4, len = 12 */
1148 uint32_t src_addr;
1149 uint32_t dst_addr;
1150 uint16_t src_port;
1151 uint16_t dst_port;
1152 } ip4;
1153 struct { /* TCP/UDP over IPv6, len = 36 */
1154 uint8_t src_addr[16];
1155 uint8_t dst_addr[16];
1156 uint16_t src_port;
1157 uint16_t dst_port;
1158 } ip6;
1159 struct { /* AF_UNIX sockets, len = 216 */
1160 uschar src_addr[108];
1161 uschar dst_addr[108];
1162 } unx;
1163 } addr;
1164 } v2;
1165 } hdr;
1166
1167 /* Temp variables used in PPv2 address:port parsing */
1168 uint16_t tmpport;
1169 char tmpip[INET_ADDRSTRLEN];
1170 struct sockaddr_in tmpaddr;
1171 char tmpip6[INET6_ADDRSTRLEN];
1172 struct sockaddr_in6 tmpaddr6;
1173
1174 /* We can't read "all data until end" because while SMTP is
1175 server-speaks-first, the TLS handshake is client-speaks-first, so for
1176 TLS-on-connect ports the proxy protocol header will usually be immediately
1177 followed by a TLS handshake, and with N TLS libraries, we can't reliably
1178 reinject data for reading by those. So instead we first read "enough to be
1179 safely read within the header, and figure out how much more to read".
1180 For v1 we will later read to the end-of-line, for v2 we will read based upon
1181 the stated length.
1182
1183 The v2 sig is 12 octets, and another 4 gets us the length, so we know how much
1184 data is needed total. For v1, where the line looks like:
1185 PROXY TCPn L3src L3dest SrcPort DestPort \r\n
1186
1187 However, for v1 there's also `PROXY UNKNOWN\r\n` which is only 15 octets.
1188 We seem to support that. So, if we read 14 octets then we can tell if we're
1189 v2 or v1. If we're v1, we can continue reading as normal.
1190
1191 If we're v2, we can't slurp up the entire header. We need the length in the
1192 15th & 16th octets, then to read everything after that.
1193
1194 So to safely handle v1 and v2, with client-sent-first supported correctly,
1195 we have to do a minimum of 3 read calls, not 1. Eww.
1196 */
1197
1198 #define PROXY_INITIAL_READ 14
1199 #define PROXY_V2_HEADER_SIZE 16
1200 #if PROXY_INITIAL_READ > PROXY_V2_HEADER_SIZE
1201 # error Code bug in sizes of data to read for proxy usage
1202 #endif
1203
1204 int get_ok = 0;
1205 int size, ret;
1206 int fd = fileno(smtp_in);
1207 const char v2sig[12] = "\x0D\x0A\x0D\x0A\x00\x0D\x0A\x51\x55\x49\x54\x0A";
1208 uschar * iptype; /* To display debug info */
1209 struct timeval tv;
1210 struct timeval tvtmp;
1211 socklen_t vslen = sizeof(struct timeval);
1212 BOOL yield = FALSE;
1213
1214 /* Save current socket timeout values */
1215 get_ok = getsockopt(fd, SOL_SOCKET, SO_RCVTIMEO, CS &tvtmp, &vslen);
1216
1217 /* Proxy Protocol host must send header within a short time
1218 (default 3 seconds) or it's considered invalid */
1219 tv.tv_sec = PROXY_NEGOTIATION_TIMEOUT_SEC;
1220 tv.tv_usec = PROXY_NEGOTIATION_TIMEOUT_USEC;
1221 if (setsockopt(fd, SOL_SOCKET, SO_RCVTIMEO, CS &tv, sizeof(tv)) < 0)
1222 goto bad;
1223
1224 do
1225 {
1226 /* The inbound host was declared to be a Proxy Protocol host, so
1227 don't do a PEEK into the data, actually slurp up enough to be
1228 "safe". Can't take it all because TLS-on-connect clients follow
1229 immediately with TLS handshake. */
1230 ret = recv(fd, &hdr, PROXY_INITIAL_READ, 0);
1231 }
1232 while (ret == -1 && errno == EINTR);
1233
1234 if (ret == -1)
1235 goto proxyfail;
1236
1237 /* For v2, handle reading the length, and then the rest. */
1238 if ((ret == PROXY_INITIAL_READ) && (memcmp(&hdr.v2, v2sig, sizeof(v2sig)) == 0))
1239 {
1240 int retmore;
1241 uint8_t ver;
1242
1243 /* First get the length fields. */
1244 do
1245 {
1246 retmore = recv(fd, (uschar*)&hdr + ret, PROXY_V2_HEADER_SIZE - PROXY_INITIAL_READ, 0);
1247 } while (retmore == -1 && errno == EINTR);
1248 if (retmore == -1)
1249 goto proxyfail;
1250 ret += retmore;
1251
1252 ver = (hdr.v2.ver_cmd & 0xf0) >> 4;
1253
1254 /* May 2014: haproxy combined the version and command into one byte to
1255 allow two full bytes for the length field in order to proxy SSL
1256 connections. SSL Proxy is not supported in this version of Exim, but
1257 must still separate values here. */
1258
1259 if (ver != 0x02)
1260 {
1261 DEBUG(D_receive) debug_printf("Invalid Proxy Protocol version: %d\n", ver);
1262 goto proxyfail;
1263 }
1264
1265 /* The v2 header will always be 16 bytes per the spec. */
1266 size = 16 + ntohs(hdr.v2.len);
1267 DEBUG(D_receive) debug_printf("Detected PROXYv2 header, size %d (limit %d)\n",
1268 size, (int)sizeof(hdr));
1269
1270 /* We should now have 16 octets (PROXY_V2_HEADER_SIZE), and we know the total
1271 amount that we need. Double-check that the size is not unreasonable, then
1272 get the rest. */
1273 if (size > sizeof(hdr))
1274 {
1275 DEBUG(D_receive) debug_printf("PROXYv2 header size unreasonably large; security attack?\n");
1276 goto proxyfail;
1277 }
1278
1279 do
1280 {
1281 do
1282 {
1283 retmore = recv(fd, (uschar*)&hdr + ret, size-ret, 0);
1284 } while (retmore == -1 && errno == EINTR);
1285 if (retmore == -1)
1286 goto proxyfail;
1287 ret += retmore;
1288 DEBUG(D_receive) debug_printf("PROXYv2: have %d/%d required octets\n", ret, size);
1289 } while (ret < size);
1290
1291 } /* end scope for getting rest of data for v2 */
1292
1293 /* At this point: if PROXYv2, we've read the exact size required for all data;
1294 if PROXYv1 then we've read "less than required for any valid line" and should
1295 read the rest". */
1296
1297 if (ret >= 16 && memcmp(&hdr.v2, v2sig, 12) == 0)
1298 {
1299 uint8_t cmd = (hdr.v2.ver_cmd & 0x0f);
1300
1301 switch (cmd)
1302 {
1303 case 0x01: /* PROXY command */
1304 switch (hdr.v2.fam)
1305 {
1306 case 0x11: /* TCPv4 address type */
1307 iptype = US"IPv4";
1308 tmpaddr.sin_addr.s_addr = hdr.v2.addr.ip4.src_addr;
1309 inet_ntop(AF_INET, &tmpaddr.sin_addr, CS &tmpip, sizeof(tmpip));
1310 if (!string_is_ip_address(US tmpip, NULL))
1311 {
1312 DEBUG(D_receive) debug_printf("Invalid %s source IP\n", iptype);
1313 goto proxyfail;
1314 }
1315 proxy_local_address = sender_host_address;
1316 sender_host_address = string_copy(US tmpip);
1317 tmpport = ntohs(hdr.v2.addr.ip4.src_port);
1318 proxy_local_port = sender_host_port;
1319 sender_host_port = tmpport;
1320 /* Save dest ip/port */
1321 tmpaddr.sin_addr.s_addr = hdr.v2.addr.ip4.dst_addr;
1322 inet_ntop(AF_INET, &tmpaddr.sin_addr, CS &tmpip, sizeof(tmpip));
1323 if (!string_is_ip_address(US tmpip, NULL))
1324 {
1325 DEBUG(D_receive) debug_printf("Invalid %s dest port\n", iptype);
1326 goto proxyfail;
1327 }
1328 proxy_external_address = string_copy(US tmpip);
1329 tmpport = ntohs(hdr.v2.addr.ip4.dst_port);
1330 proxy_external_port = tmpport;
1331 goto done;
1332 case 0x21: /* TCPv6 address type */
1333 iptype = US"IPv6";
1334 memmove(tmpaddr6.sin6_addr.s6_addr, hdr.v2.addr.ip6.src_addr, 16);
1335 inet_ntop(AF_INET6, &tmpaddr6.sin6_addr, CS &tmpip6, sizeof(tmpip6));
1336 if (!string_is_ip_address(US tmpip6, NULL))
1337 {
1338 DEBUG(D_receive) debug_printf("Invalid %s source IP\n", iptype);
1339 goto proxyfail;
1340 }
1341 proxy_local_address = sender_host_address;
1342 sender_host_address = string_copy(US tmpip6);
1343 tmpport = ntohs(hdr.v2.addr.ip6.src_port);
1344 proxy_local_port = sender_host_port;
1345 sender_host_port = tmpport;
1346 /* Save dest ip/port */
1347 memmove(tmpaddr6.sin6_addr.s6_addr, hdr.v2.addr.ip6.dst_addr, 16);
1348 inet_ntop(AF_INET6, &tmpaddr6.sin6_addr, CS &tmpip6, sizeof(tmpip6));
1349 if (!string_is_ip_address(US tmpip6, NULL))
1350 {
1351 DEBUG(D_receive) debug_printf("Invalid %s dest port\n", iptype);
1352 goto proxyfail;
1353 }
1354 proxy_external_address = string_copy(US tmpip6);
1355 tmpport = ntohs(hdr.v2.addr.ip6.dst_port);
1356 proxy_external_port = tmpport;
1357 goto done;
1358 default:
1359 DEBUG(D_receive)
1360 debug_printf("Unsupported PROXYv2 connection type: 0x%02x\n",
1361 hdr.v2.fam);
1362 goto proxyfail;
1363 }
1364 /* Unsupported protocol, keep local connection address */
1365 break;
1366 case 0x00: /* LOCAL command */
1367 /* Keep local connection address for LOCAL */
1368 iptype = US"local";
1369 break;
1370 default:
1371 DEBUG(D_receive)
1372 debug_printf("Unsupported PROXYv2 command: 0x%x\n", cmd);
1373 goto proxyfail;
1374 }
1375 }
1376 else if (ret >= 8 && memcmp(hdr.v1.line, "PROXY", 5) == 0)
1377 {
1378 uschar *p;
1379 uschar *end;
1380 uschar *sp; /* Utility variables follow */
1381 int tmp_port;
1382 int r2;
1383 char *endc;
1384
1385 /* get the rest of the line */
1386 r2 = swallow_until_crlf(fd, (uschar*)&hdr, ret, sizeof(hdr)-ret);
1387 if (r2 == -1)
1388 goto proxyfail;
1389 ret += r2;
1390
1391 p = string_copy(hdr.v1.line);
1392 end = memchr(p, '\r', ret - 1);
1393
1394 if (!end || (end == (uschar*)&hdr + ret) || end[1] != '\n')
1395 {
1396 DEBUG(D_receive) debug_printf("Partial or invalid PROXY header\n");
1397 goto proxyfail;
1398 }
1399 *end = '\0'; /* Terminate the string */
1400 size = end + 2 - p; /* Skip header + CRLF */
1401 DEBUG(D_receive) debug_printf("Detected PROXYv1 header\n");
1402 DEBUG(D_receive) debug_printf("Bytes read not within PROXY header: %d\n", ret - size);
1403 /* Step through the string looking for the required fields. Ensure
1404 strict adherence to required formatting, exit for any error. */
1405 p += 5;
1406 if (!isspace(*(p++)))
1407 {
1408 DEBUG(D_receive) debug_printf("Missing space after PROXY command\n");
1409 goto proxyfail;
1410 }
1411 if (!Ustrncmp(p, CCS"TCP4", 4))
1412 iptype = US"IPv4";
1413 else if (!Ustrncmp(p,CCS"TCP6", 4))
1414 iptype = US"IPv6";
1415 else if (!Ustrncmp(p,CCS"UNKNOWN", 7))
1416 {
1417 iptype = US"Unknown";
1418 goto done;
1419 }
1420 else
1421 {
1422 DEBUG(D_receive) debug_printf("Invalid TCP type\n");
1423 goto proxyfail;
1424 }
1425
1426 p += Ustrlen(iptype);
1427 if (!isspace(*(p++)))
1428 {
1429 DEBUG(D_receive) debug_printf("Missing space after TCP4/6 command\n");
1430 goto proxyfail;
1431 }
1432 /* Find the end of the arg */
1433 if ((sp = Ustrchr(p, ' ')) == NULL)
1434 {
1435 DEBUG(D_receive)
1436 debug_printf("Did not find proxied src %s\n", iptype);
1437 goto proxyfail;
1438 }
1439 *sp = '\0';
1440 if(!string_is_ip_address(p, NULL))
1441 {
1442 DEBUG(D_receive)
1443 debug_printf("Proxied src arg is not an %s address\n", iptype);
1444 goto proxyfail;
1445 }
1446 proxy_local_address = sender_host_address;
1447 sender_host_address = p;
1448 p = sp + 1;
1449 if ((sp = Ustrchr(p, ' ')) == NULL)
1450 {
1451 DEBUG(D_receive)
1452 debug_printf("Did not find proxy dest %s\n", iptype);
1453 goto proxyfail;
1454 }
1455 *sp = '\0';
1456 if(!string_is_ip_address(p, NULL))
1457 {
1458 DEBUG(D_receive)
1459 debug_printf("Proxy dest arg is not an %s address\n", iptype);
1460 goto proxyfail;
1461 }
1462 proxy_external_address = p;
1463 p = sp + 1;
1464 if ((sp = Ustrchr(p, ' ')) == NULL)
1465 {
1466 DEBUG(D_receive) debug_printf("Did not find proxied src port\n");
1467 goto proxyfail;
1468 }
1469 *sp = '\0';
1470 tmp_port = strtol(CCS p, &endc, 10);
1471 if (*endc || tmp_port == 0)
1472 {
1473 DEBUG(D_receive)
1474 debug_printf("Proxied src port '%s' not an integer\n", p);
1475 goto proxyfail;
1476 }
1477 proxy_local_port = sender_host_port;
1478 sender_host_port = tmp_port;
1479 p = sp + 1;
1480 if ((sp = Ustrchr(p, '\0')) == NULL)
1481 {
1482 DEBUG(D_receive) debug_printf("Did not find proxy dest port\n");
1483 goto proxyfail;
1484 }
1485 tmp_port = strtol(CCS p, &endc, 10);
1486 if (*endc || tmp_port == 0)
1487 {
1488 DEBUG(D_receive)
1489 debug_printf("Proxy dest port '%s' not an integer\n", p);
1490 goto proxyfail;
1491 }
1492 proxy_external_port = tmp_port;
1493 /* Already checked for /r /n above. Good V1 header received. */
1494 }
1495 else
1496 {
1497 /* Wrong protocol */
1498 DEBUG(D_receive) debug_printf("Invalid proxy protocol version negotiation\n");
1499 (void) swallow_until_crlf(fd, (uschar*)&hdr, ret, sizeof(hdr)-ret);
1500 goto proxyfail;
1501 }
1502
1503 done:
1504 DEBUG(D_receive)
1505 debug_printf("Valid %s sender from Proxy Protocol header\n", iptype);
1506 yield = proxy_session;
1507
1508 /* Don't flush any potential buffer contents. Any input on proxyfail
1509 should cause a synchronization failure */
1510
1511 proxyfail:
1512 restore_socket_timeout(fd, get_ok, &tvtmp, vslen);
1513
1514 bad:
1515 if (yield)
1516 {
1517 sender_host_name = NULL;
1518 (void) host_name_lookup();
1519 host_build_sender_fullhost();
1520 }
1521 else
1522 {
1523 f.proxy_session_failed = TRUE;
1524 DEBUG(D_receive)
1525 debug_printf("Failure to extract proxied host, only QUIT allowed\n");
1526 }
1527
1528 return;
1529 }
1530 #endif
1531
1532 /*************************************************
1533 * Read one command line *
1534 *************************************************/
1535
1536 /* Strictly, SMTP commands coming over the net are supposed to end with CRLF.
1537 There are sites that don't do this, and in any case internal SMTP probably
1538 should check only for LF. Consequently, we check here for LF only. The line
1539 ends up with [CR]LF removed from its end. If we get an overlong line, treat as
1540 an unknown command. The command is read into the global smtp_cmd_buffer so that
1541 it is available via $smtp_command.
1542
1543 The character reading routine sets up a timeout for each block actually read
1544 from the input (which may contain more than one command). We set up a special
1545 signal handler that closes down the session on a timeout. Control does not
1546 return when it runs.
1547
1548 Arguments:
1549 check_sync if TRUE, check synchronization rules if global option is TRUE
1550 buffer_lim maximum to buffer in lower layer
1551
1552 Returns: a code identifying the command (enumerated above)
1553 */
1554
1555 static int
1556 smtp_read_command(BOOL check_sync, unsigned buffer_lim)
1557 {
1558 int c;
1559 int ptr = 0;
1560 smtp_cmd_list *p;
1561 BOOL hadnull = FALSE;
1562
1563 had_command_timeout = 0;
1564 os_non_restarting_signal(SIGALRM, command_timeout_handler);
1565
1566 while ((c = (receive_getc)(buffer_lim)) != '\n' && c != EOF)
1567 {
1568 if (ptr >= SMTP_CMD_BUFFER_SIZE)
1569 {
1570 os_non_restarting_signal(SIGALRM, sigalrm_handler);
1571 return OTHER_CMD;
1572 }
1573 if (c == 0)
1574 {
1575 hadnull = TRUE;
1576 c = '?';
1577 }
1578 smtp_cmd_buffer[ptr++] = c;
1579 }
1580
1581 receive_linecount++; /* For BSMTP errors */
1582 os_non_restarting_signal(SIGALRM, sigalrm_handler);
1583
1584 /* If hit end of file, return pseudo EOF command. Whether we have a
1585 part-line already read doesn't matter, since this is an error state. */
1586
1587 if (c == EOF) return EOF_CMD;
1588
1589 /* Remove any CR and white space at the end of the line, and terminate the
1590 string. */
1591
1592 while (ptr > 0 && isspace(smtp_cmd_buffer[ptr-1])) ptr--;
1593 smtp_cmd_buffer[ptr] = 0;
1594
1595 DEBUG(D_receive) debug_printf("SMTP<< %s\n", smtp_cmd_buffer);
1596
1597 /* NULLs are not allowed in SMTP commands */
1598
1599 if (hadnull) return BADCHAR_CMD;
1600
1601 /* Scan command list and return identity, having set the data pointer
1602 to the start of the actual data characters. Check for SMTP synchronization
1603 if required. */
1604
1605 for (p = cmd_list; p < cmd_list_end; p++)
1606 {
1607 #ifdef SUPPORT_PROXY
1608 /* Only allow QUIT command if Proxy Protocol parsing failed */
1609 if (proxy_session && f.proxy_session_failed && p->cmd != QUIT_CMD)
1610 continue;
1611 #endif
1612 if ( p->len
1613 && strncmpic(smtp_cmd_buffer, US p->name, p->len) == 0
1614 && ( smtp_cmd_buffer[p->len-1] == ':' /* "mail from:" or "rcpt to:" */
1615 || smtp_cmd_buffer[p->len] == 0
1616 || smtp_cmd_buffer[p->len] == ' '
1617 ) )
1618 {
1619 if (smtp_inptr < smtp_inend && /* Outstanding input */
1620 p->cmd < sync_cmd_limit && /* Command should sync */
1621 check_sync && /* Local flag set */
1622 smtp_enforce_sync && /* Global flag set */
1623 sender_host_address != NULL && /* Not local input */
1624 !f.sender_host_notsocket) /* Really is a socket */
1625 return BADSYN_CMD;
1626
1627 /* The variables $smtp_command and $smtp_command_argument point into the
1628 unmodified input buffer. A copy of the latter is taken for actual
1629 processing, so that it can be chopped up into separate parts if necessary,
1630 for example, when processing a MAIL command options such as SIZE that can
1631 follow the sender address. */
1632
1633 smtp_cmd_argument = smtp_cmd_buffer + p->len;
1634 while (isspace(*smtp_cmd_argument)) smtp_cmd_argument++;
1635 Ustrcpy(smtp_data_buffer, smtp_cmd_argument);
1636 smtp_cmd_data = smtp_data_buffer;
1637
1638 /* Count non-mail commands from those hosts that are controlled in this
1639 way. The default is all hosts. We don't waste effort checking the list
1640 until we get a non-mail command, but then cache the result to save checking
1641 again. If there's a DEFER while checking the host, assume it's in the list.
1642
1643 Note that one instance of RSET, EHLO/HELO, and STARTTLS is allowed at the
1644 start of each incoming message by fiddling with the value in the table. */
1645
1646 if (!p->is_mail_cmd)
1647 {
1648 if (count_nonmail == TRUE_UNSET) count_nonmail =
1649 verify_check_host(&smtp_accept_max_nonmail_hosts) != FAIL;
1650 if (count_nonmail && ++nonmail_command_count > smtp_accept_max_nonmail)
1651 return TOO_MANY_NONMAIL_CMD;
1652 }
1653
1654 /* If there is data for a command that does not expect it, generate the
1655 error here. */
1656
1657 return (p->has_arg || *smtp_cmd_data == 0)? p->cmd : BADARG_CMD;
1658 }
1659 }
1660
1661 #ifdef SUPPORT_PROXY
1662 /* Only allow QUIT command if Proxy Protocol parsing failed */
1663 if (proxy_session && f.proxy_session_failed)
1664 return PROXY_FAIL_IGNORE_CMD;
1665 #endif
1666
1667 /* Enforce synchronization for unknown commands */
1668
1669 if ( smtp_inptr < smtp_inend /* Outstanding input */
1670 && check_sync /* Local flag set */
1671 && smtp_enforce_sync /* Global flag set */
1672 && sender_host_address /* Not local input */
1673 && !f.sender_host_notsocket) /* Really is a socket */
1674 return BADSYN_CMD;
1675
1676 return OTHER_CMD;
1677 }
1678
1679
1680
1681 /*************************************************
1682 * Forced closedown of call *
1683 *************************************************/
1684
1685 /* This function is called from log.c when Exim is dying because of a serious
1686 disaster, and also from some other places. If an incoming non-batched SMTP
1687 channel is open, it swallows the rest of the incoming message if in the DATA
1688 phase, sends the reply string, and gives an error to all subsequent commands
1689 except QUIT. The existence of an SMTP call is detected by the non-NULLness of
1690 smtp_in.
1691
1692 Arguments:
1693 message SMTP reply string to send, excluding the code
1694
1695 Returns: nothing
1696 */
1697
1698 void
1699 smtp_closedown(uschar *message)
1700 {
1701 if (!smtp_in || smtp_batched_input) return;
1702 receive_swallow_smtp();
1703 smtp_printf("421 %s\r\n", FALSE, message);
1704
1705 for (;;) switch(smtp_read_command(FALSE, GETC_BUFFER_UNLIMITED))
1706 {
1707 case EOF_CMD:
1708 return;
1709
1710 case QUIT_CMD:
1711 smtp_printf("221 %s closing connection\r\n", FALSE, smtp_active_hostname);
1712 mac_smtp_fflush();
1713 return;
1714
1715 case RSET_CMD:
1716 smtp_printf("250 Reset OK\r\n", FALSE);
1717 break;
1718
1719 default:
1720 smtp_printf("421 %s\r\n", FALSE, message);
1721 break;
1722 }
1723 }
1724
1725
1726
1727
1728 /*************************************************
1729 * Set up connection info for logging *
1730 *************************************************/
1731
1732 /* This function is called when logging information about an SMTP connection.
1733 It sets up appropriate source information, depending on the type of connection.
1734 If sender_fullhost is NULL, we are at a very early stage of the connection;
1735 just use the IP address.
1736
1737 Argument: none
1738 Returns: a string describing the connection
1739 */
1740
1741 uschar *
1742 smtp_get_connection_info(void)
1743 {
1744 const uschar * hostname = sender_fullhost
1745 ? sender_fullhost : sender_host_address;
1746
1747 if (host_checking)
1748 return string_sprintf("SMTP connection from %s", hostname);
1749
1750 if (f.sender_host_unknown || f.sender_host_notsocket)
1751 return string_sprintf("SMTP connection from %s", sender_ident);
1752
1753 if (f.is_inetd)
1754 return string_sprintf("SMTP connection from %s (via inetd)", hostname);
1755
1756 if (LOGGING(incoming_interface) && interface_address != NULL)
1757 return string_sprintf("SMTP connection from %s I=[%s]:%d", hostname,
1758 interface_address, interface_port);
1759
1760 return string_sprintf("SMTP connection from %s", hostname);
1761 }
1762
1763
1764
1765 #ifdef SUPPORT_TLS
1766 /* Append TLS-related information to a log line
1767
1768 Arguments:
1769 g String under construction: allocated string to extend, or NULL
1770
1771 Returns: Allocated string or NULL
1772 */
1773 static gstring *
1774 s_tlslog(gstring * g)
1775 {
1776 if (LOGGING(tls_cipher) && tls_in.cipher)
1777 g = string_append(g, 2, US" X=", tls_in.cipher);
1778 if (LOGGING(tls_certificate_verified) && tls_in.cipher)
1779 g = string_append(g, 2, US" CV=", tls_in.certificate_verified? "yes":"no");
1780 if (LOGGING(tls_peerdn) && tls_in.peerdn)
1781 g = string_append(g, 3, US" DN=\"", string_printing(tls_in.peerdn), US"\"");
1782 if (LOGGING(tls_sni) && tls_in.sni)
1783 g = string_append(g, 3, US" SNI=\"", string_printing(tls_in.sni), US"\"");
1784 return g;
1785 }
1786 #endif
1787
1788 /*************************************************
1789 * Log lack of MAIL if so configured *
1790 *************************************************/
1791
1792 /* This function is called when an SMTP session ends. If the log selector
1793 smtp_no_mail is set, write a log line giving some details of what has happened
1794 in the SMTP session.
1795
1796 Arguments: none
1797 Returns: nothing
1798 */
1799
1800 void
1801 smtp_log_no_mail(void)
1802 {
1803 int i;
1804 uschar * sep, * s;
1805 gstring * g = NULL;
1806
1807 if (smtp_mailcmd_count > 0 || !LOGGING(smtp_no_mail))
1808 return;
1809
1810 if (sender_host_authenticated)
1811 {
1812 g = string_append(g, 2, US" A=", sender_host_authenticated);
1813 if (authenticated_id) g = string_append(g, 2, US":", authenticated_id);
1814 }
1815
1816 #ifdef SUPPORT_TLS
1817 g = s_tlslog(g);
1818 #endif
1819
1820 sep = smtp_connection_had[SMTP_HBUFF_SIZE-1] != SCH_NONE ? US" C=..." : US" C=";
1821
1822 for (i = smtp_ch_index; i < SMTP_HBUFF_SIZE; i++)
1823 if (smtp_connection_had[i] != SCH_NONE)
1824 {
1825 g = string_append(g, 2, sep, smtp_names[smtp_connection_had[i]]);
1826 sep = US",";
1827 }
1828
1829 for (i = 0; i < smtp_ch_index; i++)
1830 {
1831 g = string_append(g, 2, sep, smtp_names[smtp_connection_had[i]]);
1832 sep = US",";
1833 }
1834
1835 if (!(s = string_from_gstring(g))) s = US"";
1836
1837 log_write(0, LOG_MAIN, "no MAIL in %sSMTP connection from %s D=%s%s",
1838 f.tcp_in_fastopen ? US"TFO " : US"",
1839 host_and_ident(FALSE), string_timesince(&smtp_connection_start), s);
1840 }
1841
1842
1843 /* Return list of recent smtp commands */
1844
1845 uschar *
1846 smtp_cmd_hist(void)
1847 {
1848 int i;
1849 gstring * list = NULL;
1850 uschar * s;
1851
1852 for (i = smtp_ch_index; i < SMTP_HBUFF_SIZE; i++)
1853 if (smtp_connection_had[i] != SCH_NONE)
1854 list = string_append_listele(list, ',', smtp_names[smtp_connection_had[i]]);
1855
1856 for (i = 0; i < smtp_ch_index; i++)
1857 list = string_append_listele(list, ',', smtp_names[smtp_connection_had[i]]);
1858
1859 s = string_from_gstring(list);
1860 return s ? s : US"";
1861 }
1862
1863
1864
1865
1866 /*************************************************
1867 * Check HELO line and set sender_helo_name *
1868 *************************************************/
1869
1870 /* Check the format of a HELO line. The data for HELO/EHLO is supposed to be
1871 the domain name of the sending host, or an ip literal in square brackets. The
1872 argument is placed in sender_helo_name, which is in malloc store, because it
1873 must persist over multiple incoming messages. If helo_accept_junk is set, this
1874 host is permitted to send any old junk (needed for some broken hosts).
1875 Otherwise, helo_allow_chars can be used for rogue characters in general
1876 (typically people want to let in underscores).
1877
1878 Argument:
1879 s the data portion of the line (already past any white space)
1880
1881 Returns: TRUE or FALSE
1882 */
1883
1884 static BOOL
1885 check_helo(uschar *s)
1886 {
1887 uschar *start = s;
1888 uschar *end = s + Ustrlen(s);
1889 BOOL yield = helo_accept_junk;
1890
1891 /* Discard any previous helo name */
1892
1893 if (sender_helo_name)
1894 {
1895 store_free(sender_helo_name);
1896 sender_helo_name = NULL;
1897 }
1898
1899 /* Skip tests if junk is permitted. */
1900
1901 if (!yield)
1902
1903 /* Allow the new standard form for IPv6 address literals, namely,
1904 [IPv6:....], and because someone is bound to use it, allow an equivalent
1905 IPv4 form. Allow plain addresses as well. */
1906
1907 if (*s == '[')
1908 {
1909 if (end[-1] == ']')
1910 {
1911 end[-1] = 0;
1912 if (strncmpic(s, US"[IPv6:", 6) == 0)
1913 yield = (string_is_ip_address(s+6, NULL) == 6);
1914 else if (strncmpic(s, US"[IPv4:", 6) == 0)
1915 yield = (string_is_ip_address(s+6, NULL) == 4);
1916 else
1917 yield = (string_is_ip_address(s+1, NULL) != 0);
1918 end[-1] = ']';
1919 }
1920 }
1921
1922 /* Non-literals must be alpha, dot, hyphen, plus any non-valid chars
1923 that have been configured (usually underscore - sigh). */
1924
1925 else if (*s)
1926 for (yield = TRUE; *s; s++)
1927 if (!isalnum(*s) && *s != '.' && *s != '-' &&
1928 Ustrchr(helo_allow_chars, *s) == NULL)
1929 {
1930 yield = FALSE;
1931 break;
1932 }
1933
1934 /* Save argument if OK */
1935
1936 if (yield) sender_helo_name = string_copy_malloc(start);
1937 return yield;
1938 }
1939
1940
1941
1942
1943
1944 /*************************************************
1945 * Extract SMTP command option *
1946 *************************************************/
1947
1948 /* This function picks the next option setting off the end of smtp_cmd_data. It
1949 is called for MAIL FROM and RCPT TO commands, to pick off the optional ESMTP
1950 things that can appear there.
1951
1952 Arguments:
1953 name point this at the name
1954 value point this at the data string
1955
1956 Returns: TRUE if found an option
1957 */
1958
1959 static BOOL
1960 extract_option(uschar **name, uschar **value)
1961 {
1962 uschar *n;
1963 uschar *v = smtp_cmd_data + Ustrlen(smtp_cmd_data) - 1;
1964 while (isspace(*v)) v--;
1965 v[1] = 0;
1966 while (v > smtp_cmd_data && *v != '=' && !isspace(*v))
1967 {
1968 /* Take care to not stop at a space embedded in a quoted local-part */
1969
1970 if (*v == '"') do v--; while (*v != '"' && v > smtp_cmd_data+1);
1971 v--;
1972 }
1973
1974 n = v;
1975 if (*v == '=')
1976 {
1977 while(isalpha(n[-1])) n--;
1978 /* RFC says SP, but TAB seen in wild and other major MTAs accept it */
1979 if (!isspace(n[-1])) return FALSE;
1980 n[-1] = 0;
1981 }
1982 else
1983 {
1984 n++;
1985 if (v == smtp_cmd_data) return FALSE;
1986 }
1987 *v++ = 0;
1988 *name = n;
1989 *value = v;
1990 return TRUE;
1991 }
1992
1993
1994
1995
1996
1997 /*************************************************
1998 * Reset for new message *
1999 *************************************************/
2000
2001 /* This function is called whenever the SMTP session is reset from
2002 within either of the setup functions; also from the daemon loop.
2003
2004 Argument: the stacking pool storage reset point
2005 Returns: nothing
2006 */
2007
2008 void
2009 smtp_reset(void *reset_point)
2010 {
2011 recipients_list = NULL;
2012 rcpt_count = rcpt_defer_count = rcpt_fail_count =
2013 raw_recipients_count = recipients_count = recipients_list_max = 0;
2014 message_linecount = 0;
2015 message_size = -1;
2016 acl_added_headers = NULL;
2017 acl_removed_headers = NULL;
2018 f.queue_only_policy = FALSE;
2019 rcpt_smtp_response = NULL;
2020 rcpt_smtp_response_same = TRUE;
2021 rcpt_in_progress = FALSE;
2022 f.deliver_freeze = FALSE; /* Can be set by ACL */
2023 freeze_tell = freeze_tell_config; /* Can be set by ACL */
2024 fake_response = OK; /* Can be set by ACL */
2025 #ifdef WITH_CONTENT_SCAN
2026 f.no_mbox_unspool = FALSE; /* Can be set by ACL */
2027 #endif
2028 f.submission_mode = FALSE; /* Can be set by ACL */
2029 f.suppress_local_fixups = f.suppress_local_fixups_default; /* Can be set by ACL */
2030 f.active_local_from_check = local_from_check; /* Can be set by ACL */
2031 f.active_local_sender_retain = local_sender_retain; /* Can be set by ACL */
2032 sending_ip_address = NULL;
2033 return_path = sender_address = NULL;
2034 sender_data = NULL; /* Can be set by ACL */
2035 deliver_localpart_parent = deliver_localpart_orig = NULL;
2036 deliver_domain_parent = deliver_domain_orig = NULL;
2037 callout_address = NULL;
2038 submission_name = NULL; /* Can be set by ACL */
2039 raw_sender = NULL; /* After SMTP rewrite, before qualifying */
2040 sender_address_unrewritten = NULL; /* Set only after verify rewrite */
2041 sender_verified_list = NULL; /* No senders verified */
2042 memset(sender_address_cache, 0, sizeof(sender_address_cache));
2043 memset(sender_domain_cache, 0, sizeof(sender_domain_cache));
2044
2045 authenticated_sender = NULL;
2046 #ifdef EXPERIMENTAL_BRIGHTMAIL
2047 bmi_run = 0;
2048 bmi_verdicts = NULL;
2049 #endif
2050 dnslist_domain = dnslist_matched = NULL;
2051 #ifdef SUPPORT_SPF
2052 spf_header_comment = spf_received = spf_result = spf_smtp_comment = NULL;
2053 spf_result_guessed = FALSE;
2054 #endif
2055 #ifndef DISABLE_DKIM
2056 dkim_cur_signer = dkim_signers =
2057 dkim_signing_domain = dkim_signing_selector = dkim_signatures = NULL;
2058 dkim_cur_signer = dkim_signers = dkim_signing_domain = dkim_signing_selector = NULL;
2059 f.dkim_disable_verify = FALSE;
2060 dkim_collect_input = 0;
2061 dkim_verify_overall = dkim_verify_status = dkim_verify_reason = NULL;
2062 dkim_key_length = 0;
2063 dkim_verify_signers = US"$dkim_signers";
2064 #endif
2065 #ifdef EXPERIMENTAL_DMARC
2066 f.dmarc_has_been_checked = f.dmarc_disable_verify = f.dmarc_enable_forensic = FALSE;
2067 dmarc_domain_policy = dmarc_status = dmarc_status_text =
2068 dmarc_used_domain = NULL;
2069 #endif
2070 #ifdef EXPERIMENTAL_ARC
2071 arc_state = arc_state_reason = NULL;
2072 #endif
2073 dsn_ret = 0;
2074 dsn_envid = NULL;
2075 deliver_host = deliver_host_address = NULL; /* Can be set by ACL */
2076 #ifndef DISABLE_PRDR
2077 prdr_requested = FALSE;
2078 #endif
2079 #ifdef SUPPORT_I18N
2080 message_smtputf8 = FALSE;
2081 #endif
2082 body_linecount = body_zerocount = 0;
2083
2084 sender_rate = sender_rate_limit = sender_rate_period = NULL;
2085 ratelimiters_mail = NULL; /* Updated by ratelimit ACL condition */
2086 /* Note that ratelimiters_conn persists across resets. */
2087
2088 /* Reset message ACL variables */
2089
2090 acl_var_m = NULL;
2091
2092 /* The message body variables use malloc store. They may be set if this is
2093 not the first message in an SMTP session and the previous message caused them
2094 to be referenced in an ACL. */
2095
2096 if (message_body)
2097 {
2098 store_free(message_body);
2099 message_body = NULL;
2100 }
2101
2102 if (message_body_end)
2103 {
2104 store_free(message_body_end);
2105 message_body_end = NULL;
2106 }
2107
2108 /* Warning log messages are also saved in malloc store. They are saved to avoid
2109 repetition in the same message, but it seems right to repeat them for different
2110 messages. */
2111
2112 while (acl_warn_logged)
2113 {
2114 string_item *this = acl_warn_logged;
2115 acl_warn_logged = acl_warn_logged->next;
2116 store_free(this);
2117 }
2118 store_reset(reset_point);
2119 }
2120
2121
2122
2123
2124
2125 /*************************************************
2126 * Initialize for incoming batched SMTP message *
2127 *************************************************/
2128
2129 /* This function is called from smtp_setup_msg() in the case when
2130 smtp_batched_input is true. This happens when -bS is used to pass a whole batch
2131 of messages in one file with SMTP commands between them. All errors must be
2132 reported by sending a message, and only MAIL FROM, RCPT TO, and DATA are
2133 relevant. After an error on a sender, or an invalid recipient, the remainder
2134 of the message is skipped. The value of received_protocol is already set.
2135
2136 Argument: none
2137 Returns: > 0 message successfully started (reached DATA)
2138 = 0 QUIT read or end of file reached
2139 < 0 should not occur
2140 */
2141
2142 static int
2143 smtp_setup_batch_msg(void)
2144 {
2145 int done = 0;
2146 void *reset_point = store_get(0);
2147
2148 /* Save the line count at the start of each transaction - single commands
2149 like HELO and RSET count as whole transactions. */
2150
2151 bsmtp_transaction_linecount = receive_linecount;
2152
2153 if ((receive_feof)()) return 0; /* Treat EOF as QUIT */
2154
2155 cancel_cutthrough_connection(TRUE, US"smtp_setup_batch_msg");
2156 smtp_reset(reset_point); /* Reset for start of message */
2157
2158 /* Deal with SMTP commands. This loop is exited by setting done to a POSITIVE
2159 value. The values are 2 larger than the required yield of the function. */
2160
2161 while (done <= 0)
2162 {
2163 uschar *errmess;
2164 uschar *recipient = NULL;
2165 int start, end, sender_domain, recipient_domain;
2166
2167 switch(smtp_read_command(FALSE, GETC_BUFFER_UNLIMITED))
2168 {
2169 /* The HELO/EHLO commands set sender_address_helo if they have
2170 valid data; otherwise they are ignored, except that they do
2171 a reset of the state. */
2172
2173 case HELO_CMD:
2174 case EHLO_CMD:
2175
2176 check_helo(smtp_cmd_data);
2177 /* Fall through */
2178
2179 case RSET_CMD:
2180 cancel_cutthrough_connection(TRUE, US"RSET received");
2181 smtp_reset(reset_point);
2182 bsmtp_transaction_linecount = receive_linecount;
2183 break;
2184
2185
2186 /* The MAIL FROM command requires an address as an operand. All we
2187 do here is to parse it for syntactic correctness. The form "<>" is
2188 a special case which converts into an empty string. The start/end
2189 pointers in the original are not used further for this address, as
2190 it is the canonical extracted address which is all that is kept. */
2191
2192 case MAIL_CMD:
2193 smtp_mailcmd_count++; /* Count for no-mail log */
2194 if (sender_address != NULL)
2195 /* The function moan_smtp_batch() does not return. */
2196 moan_smtp_batch(smtp_cmd_buffer, "503 Sender already given");
2197
2198 if (smtp_cmd_data[0] == 0)
2199 /* The function moan_smtp_batch() does not return. */
2200 moan_smtp_batch(smtp_cmd_buffer, "501 MAIL FROM must have an address operand");
2201
2202 /* Reset to start of message */
2203
2204 cancel_cutthrough_connection(TRUE, US"MAIL received");
2205 smtp_reset(reset_point);
2206
2207 /* Apply SMTP rewrite */
2208
2209 raw_sender = ((rewrite_existflags & rewrite_smtp) != 0)?
2210 rewrite_one(smtp_cmd_data, rewrite_smtp|rewrite_smtp_sender, NULL, FALSE,
2211 US"", global_rewrite_rules) : smtp_cmd_data;
2212
2213 /* Extract the address; the TRUE flag allows <> as valid */
2214
2215 raw_sender =
2216 parse_extract_address(raw_sender, &errmess, &start, &end, &sender_domain,
2217 TRUE);
2218
2219 if (!raw_sender)
2220 /* The function moan_smtp_batch() does not return. */
2221 moan_smtp_batch(smtp_cmd_buffer, "501 %s", errmess);
2222
2223 sender_address = string_copy(raw_sender);
2224
2225 /* Qualify unqualified sender addresses if permitted to do so. */
2226
2227 if ( !sender_domain
2228 && sender_address[0] != 0 && sender_address[0] != '@')
2229 if (f.allow_unqualified_sender)
2230 {
2231 sender_address = rewrite_address_qualify(sender_address, FALSE);
2232 DEBUG(D_receive) debug_printf("unqualified address %s accepted "
2233 "and rewritten\n", raw_sender);
2234 }
2235 /* The function moan_smtp_batch() does not return. */
2236 else
2237 moan_smtp_batch(smtp_cmd_buffer, "501 sender address must contain "
2238 "a domain");
2239 break;
2240
2241
2242 /* The RCPT TO command requires an address as an operand. All we do
2243 here is to parse it for syntactic correctness. There may be any number
2244 of RCPT TO commands, specifying multiple senders. We build them all into
2245 a data structure that is in argc/argv format. The start/end values
2246 given by parse_extract_address are not used, as we keep only the
2247 extracted address. */
2248
2249 case RCPT_CMD:
2250 if (!sender_address)
2251 /* The function moan_smtp_batch() does not return. */
2252 moan_smtp_batch(smtp_cmd_buffer, "503 No sender yet given");
2253
2254 if (smtp_cmd_data[0] == 0)
2255 /* The function moan_smtp_batch() does not return. */
2256 moan_smtp_batch(smtp_cmd_buffer,
2257 "501 RCPT TO must have an address operand");
2258
2259 /* Check maximum number allowed */
2260
2261 if (recipients_max > 0 && recipients_count + 1 > recipients_max)
2262 /* The function moan_smtp_batch() does not return. */
2263 moan_smtp_batch(smtp_cmd_buffer, "%s too many recipients",
2264 recipients_max_reject? "552": "452");
2265
2266 /* Apply SMTP rewrite, then extract address. Don't allow "<>" as a
2267 recipient address */
2268
2269 recipient = rewrite_existflags & rewrite_smtp
2270 ? rewrite_one(smtp_cmd_data, rewrite_smtp, NULL, FALSE, US"",
2271 global_rewrite_rules)
2272 : smtp_cmd_data;
2273
2274 recipient = parse_extract_address(recipient, &errmess, &start, &end,
2275 &recipient_domain, FALSE);
2276
2277 if (!recipient)
2278 /* The function moan_smtp_batch() does not return. */
2279 moan_smtp_batch(smtp_cmd_buffer, "501 %s", errmess);
2280
2281 /* If the recipient address is unqualified, qualify it if permitted. Then
2282 add it to the list of recipients. */
2283
2284 if (!recipient_domain)
2285 if (f.allow_unqualified_recipient)
2286 {
2287 DEBUG(D_receive) debug_printf("unqualified address %s accepted\n",
2288 recipient);
2289 recipient = rewrite_address_qualify(recipient, TRUE);
2290 }
2291 /* The function moan_smtp_batch() does not return. */
2292 else
2293 moan_smtp_batch(smtp_cmd_buffer,
2294 "501 recipient address must contain a domain");
2295
2296 receive_add_recipient(recipient, -1);
2297 break;
2298
2299
2300 /* The DATA command is legal only if it follows successful MAIL FROM
2301 and RCPT TO commands. This function is complete when a valid DATA
2302 command is encountered. */
2303
2304 case DATA_CMD:
2305 if (!sender_address || recipients_count <= 0)
2306 /* The function moan_smtp_batch() does not return. */
2307 if (!sender_address)
2308 moan_smtp_batch(smtp_cmd_buffer,
2309 "503 MAIL FROM:<sender> command must precede DATA");
2310 else
2311 moan_smtp_batch(smtp_cmd_buffer,
2312 "503 RCPT TO:<recipient> must precede DATA");
2313 else
2314 {
2315 done = 3; /* DATA successfully achieved */
2316 message_ended = END_NOTENDED; /* Indicate in middle of message */
2317 }
2318 break;
2319
2320
2321 /* The VRFY, EXPN, HELP, ETRN, and NOOP commands are ignored. */
2322
2323 case VRFY_CMD:
2324 case EXPN_CMD:
2325 case HELP_CMD:
2326 case NOOP_CMD:
2327 case ETRN_CMD:
2328 bsmtp_transaction_linecount = receive_linecount;
2329 break;
2330
2331
2332 case EOF_CMD:
2333 case QUIT_CMD:
2334 done = 2;
2335 break;
2336
2337
2338 case BADARG_CMD:
2339 /* The function moan_smtp_batch() does not return. */
2340 moan_smtp_batch(smtp_cmd_buffer, "501 Unexpected argument data");
2341 break;
2342
2343
2344 case BADCHAR_CMD:
2345 /* The function moan_smtp_batch() does not return. */
2346 moan_smtp_batch(smtp_cmd_buffer, "501 Unexpected NULL in SMTP command");
2347 break;
2348
2349
2350 default:
2351 /* The function moan_smtp_batch() does not return. */
2352 moan_smtp_batch(smtp_cmd_buffer, "500 Command unrecognized");
2353 break;
2354 }
2355 }
2356
2357 return done - 2; /* Convert yield values */
2358 }
2359
2360
2361
2362
2363 static BOOL
2364 smtp_log_tls_fail(uschar * errstr)
2365 {
2366 uschar * conn_info = smtp_get_connection_info();
2367
2368 if (Ustrncmp(conn_info, US"SMTP ", 5) == 0) conn_info += 5;
2369 /* I'd like to get separated H= here, but too hard for now */
2370
2371 log_write(0, LOG_MAIN, "TLS error on %s %s", conn_info, errstr);
2372 return FALSE;
2373 }
2374
2375
2376
2377
2378 #ifdef TCP_FASTOPEN
2379 static void
2380 tfo_in_check(void)
2381 {
2382 # ifdef TCP_INFO
2383 struct tcp_info tinfo;
2384 socklen_t len = sizeof(tinfo);
2385
2386 if ( getsockopt(fileno(smtp_out), IPPROTO_TCP, TCP_INFO, &tinfo, &len) == 0
2387 && tinfo.tcpi_state == TCP_SYN_RECV
2388 )
2389 {
2390 DEBUG(D_receive) debug_printf("TCP_FASTOPEN mode connection (state TCP_SYN_RECV)\n");
2391 f.tcp_in_fastopen = TRUE;
2392 }
2393 # endif
2394 }
2395 #endif
2396
2397
2398 /*************************************************
2399 * Start an SMTP session *
2400 *************************************************/
2401
2402 /* This function is called at the start of an SMTP session. Thereafter,
2403 smtp_setup_msg() is called to initiate each separate message. This
2404 function does host-specific testing, and outputs the banner line.
2405
2406 Arguments: none
2407 Returns: FALSE if the session can not continue; something has
2408 gone wrong, or the connection to the host is blocked
2409 */
2410
2411 BOOL
2412 smtp_start_session(void)
2413 {
2414 int esclen;
2415 uschar *user_msg, *log_msg;
2416 uschar *code, *esc;
2417 uschar *p, *s;
2418 gstring * ss;
2419
2420 gettimeofday(&smtp_connection_start, NULL);
2421 for (smtp_ch_index = 0; smtp_ch_index < SMTP_HBUFF_SIZE; smtp_ch_index++)
2422 smtp_connection_had[smtp_ch_index] = SCH_NONE;
2423 smtp_ch_index = 0;
2424
2425 /* Default values for certain variables */
2426
2427 helo_seen = esmtp = helo_accept_junk = FALSE;
2428 smtp_mailcmd_count = 0;
2429 count_nonmail = TRUE_UNSET;
2430 synprot_error_count = unknown_command_count = nonmail_command_count = 0;
2431 smtp_delay_mail = smtp_rlm_base;
2432 auth_advertised = FALSE;
2433 f.smtp_in_pipelining_advertised = f.smtp_in_pipelining_used = FALSE;
2434 f.pipelining_enable = TRUE;
2435 sync_cmd_limit = NON_SYNC_CMD_NON_PIPELINING;
2436 smtp_exit_function_called = FALSE; /* For avoiding loop in not-quit exit */
2437
2438 /* If receiving by -bs from a trusted user, or testing with -bh, we allow
2439 authentication settings from -oMaa to remain in force. */
2440
2441 if (!host_checking && !f.sender_host_notsocket)
2442 sender_host_auth_pubname = sender_host_authenticated = NULL;
2443 authenticated_by = NULL;
2444
2445 #ifdef SUPPORT_TLS
2446 tls_in.cipher = tls_in.peerdn = NULL;
2447 tls_in.ourcert = tls_in.peercert = NULL;
2448 tls_in.sni = NULL;
2449 tls_in.ocsp = OCSP_NOT_REQ;
2450 tls_advertised = FALSE;
2451 # ifdef EXPERIMENTAL_REQUIRETLS
2452 requiretls_advertised = FALSE;
2453 # endif
2454 #endif
2455 dsn_advertised = FALSE;
2456 #ifdef SUPPORT_I18N
2457 smtputf8_advertised = FALSE;
2458 #endif
2459
2460 /* Reset ACL connection variables */
2461
2462 acl_var_c = NULL;
2463
2464 /* Allow for trailing 0 in the command and data buffers. */
2465
2466 if (!(smtp_cmd_buffer = US malloc(2*SMTP_CMD_BUFFER_SIZE + 2)))
2467 log_write(0, LOG_MAIN|LOG_PANIC_DIE,
2468 "malloc() failed for SMTP command buffer");
2469
2470 smtp_cmd_buffer[0] = 0;
2471 smtp_data_buffer = smtp_cmd_buffer + SMTP_CMD_BUFFER_SIZE + 1;
2472
2473 /* For batched input, the protocol setting can be overridden from the
2474 command line by a trusted caller. */
2475
2476 if (smtp_batched_input)
2477 {
2478 if (!received_protocol) received_protocol = US"local-bsmtp";
2479 }
2480
2481 /* For non-batched SMTP input, the protocol setting is forced here. It will be
2482 reset later if any of EHLO/AUTH/STARTTLS are received. */
2483
2484 else
2485 received_protocol =
2486 (sender_host_address ? protocols : protocols_local) [pnormal];
2487
2488 /* Set up the buffer for inputting using direct read() calls, and arrange to
2489 call the local functions instead of the standard C ones. Place a NUL at the
2490 end of the buffer to safety-stop C-string reads from it. */
2491
2492 if (!(smtp_inbuffer = US malloc(IN_BUFFER_SIZE)))
2493 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "malloc() failed for SMTP input buffer");
2494 smtp_inbuffer[IN_BUFFER_SIZE-1] = '\0';
2495
2496 receive_getc = smtp_getc;
2497 receive_getbuf = smtp_getbuf;
2498 receive_get_cache = smtp_get_cache;
2499 receive_ungetc = smtp_ungetc;
2500 receive_feof = smtp_feof;
2501 receive_ferror = smtp_ferror;
2502 receive_smtp_buffered = smtp_buffered;
2503 smtp_inptr = smtp_inend = smtp_inbuffer;
2504 smtp_had_eof = smtp_had_error = 0;
2505
2506 /* Set up the message size limit; this may be host-specific */
2507
2508 thismessage_size_limit = expand_string_integer(message_size_limit, TRUE);
2509 if (expand_string_message)
2510 {
2511 if (thismessage_size_limit == -1)
2512 log_write(0, LOG_MAIN|LOG_PANIC, "unable to expand message_size_limit: "
2513 "%s", expand_string_message);
2514 else
2515 log_write(0, LOG_MAIN|LOG_PANIC, "invalid message_size_limit: "
2516 "%s", expand_string_message);
2517 smtp_closedown(US"Temporary local problem - please try later");
2518 return FALSE;
2519 }
2520
2521 /* When a message is input locally via the -bs or -bS options, sender_host_
2522 unknown is set unless -oMa was used to force an IP address, in which case it
2523 is checked like a real remote connection. When -bs is used from inetd, this
2524 flag is not set, causing the sending host to be checked. The code that deals
2525 with IP source routing (if configured) is never required for -bs or -bS and
2526 the flag sender_host_notsocket is used to suppress it.
2527
2528 If smtp_accept_max and smtp_accept_reserve are set, keep some connections in
2529 reserve for certain hosts and/or networks. */
2530
2531 if (!f.sender_host_unknown)
2532 {
2533 int rc;
2534 BOOL reserved_host = FALSE;
2535
2536 /* Look up IP options (source routing info) on the socket if this is not an
2537 -oMa "host", and if any are found, log them and drop the connection.
2538
2539 Linux (and others now, see below) is different to everyone else, so there
2540 has to be some conditional compilation here. Versions of Linux before 2.1.15
2541 used a structure whose name was "options". Somebody finally realized that
2542 this name was silly, and it got changed to "ip_options". I use the
2543 newer name here, but there is a fudge in the script that sets up os.h
2544 to define a macro in older Linux systems.
2545
2546 Sigh. Linux is a fast-moving target. Another generation of Linux uses
2547 glibc 2, which has chosen ip_opts for the structure name. This is now
2548 really a glibc thing rather than a Linux thing, so the condition name
2549 has been changed to reflect this. It is relevant also to GNU/Hurd.
2550
2551 Mac OS 10.x (Darwin) is like the later glibc versions, but without the
2552 setting of the __GLIBC__ macro, so we can't detect it automatically. There's
2553 a special macro defined in the os.h file.
2554
2555 Some DGUX versions on older hardware appear not to support IP options at
2556 all, so there is now a general macro which can be set to cut out this
2557 support altogether.
2558
2559 How to do this properly in IPv6 is not yet known. */
2560
2561 #if !HAVE_IPV6 && !defined(NO_IP_OPTIONS)
2562
2563 #ifdef GLIBC_IP_OPTIONS
2564 #if (!defined __GLIBC__) || (__GLIBC__ < 2)
2565 #define OPTSTYLE 1
2566 #else
2567 #define OPTSTYLE 2
2568 #endif
2569 #elif defined DARWIN_IP_OPTIONS
2570 #define OPTSTYLE 2
2571 #else
2572 #define OPTSTYLE 3
2573 #endif
2574
2575 if (!host_checking && !f.sender_host_notsocket)
2576 {
2577 #if OPTSTYLE == 1
2578 EXIM_SOCKLEN_T optlen = sizeof(struct ip_options) + MAX_IPOPTLEN;
2579 struct ip_options *ipopt = store_get(optlen);
2580 #elif OPTSTYLE == 2
2581 struct ip_opts ipoptblock;
2582 struct ip_opts *ipopt = &ipoptblock;
2583 EXIM_SOCKLEN_T optlen = sizeof(ipoptblock);
2584 #else
2585 struct ipoption ipoptblock;
2586 struct ipoption *ipopt = &ipoptblock;
2587 EXIM_SOCKLEN_T optlen = sizeof(ipoptblock);
2588 #endif
2589
2590 /* Occasional genuine failures of getsockopt() have been seen - for
2591 example, "reset by peer". Therefore, just log and give up on this
2592 call, unless the error is ENOPROTOOPT. This error is given by systems
2593 that have the interfaces but not the mechanism - e.g. GNU/Hurd at the time
2594 of writing. So for that error, carry on - we just can't do an IP options
2595 check. */
2596
2597 DEBUG(D_receive) debug_printf("checking for IP options\n");
2598
2599 if (getsockopt(fileno(smtp_out), IPPROTO_IP, IP_OPTIONS, US (ipopt),
2600 &optlen) < 0)
2601 {
2602 if (errno != ENOPROTOOPT)
2603 {
2604 log_write(0, LOG_MAIN, "getsockopt() failed from %s: %s",
2605 host_and_ident(FALSE), strerror(errno));
2606 smtp_printf("451 SMTP service not available\r\n", FALSE);
2607 return FALSE;
2608 }
2609 }
2610
2611 /* Deal with any IP options that are set. On the systems I have looked at,
2612 the value of MAX_IPOPTLEN has been 40, meaning that there should never be
2613 more logging data than will fit in big_buffer. Nevertheless, after somebody
2614 questioned this code, I've added in some paranoid checking. */
2615
2616 else if (optlen > 0)
2617 {
2618 uschar *p = big_buffer;
2619 uschar *pend = big_buffer + big_buffer_size;
2620 uschar *opt, *adptr;
2621 int optcount;
2622 struct in_addr addr;
2623
2624 #if OPTSTYLE == 1
2625 uschar *optstart = US (ipopt->__data);
2626 #elif OPTSTYLE == 2
2627 uschar *optstart = US (ipopt->ip_opts);
2628 #else
2629 uschar *optstart = US (ipopt->ipopt_list);
2630 #endif
2631
2632 DEBUG(D_receive) debug_printf("IP options exist\n");
2633
2634 Ustrcpy(p, "IP options on incoming call:");
2635 p += Ustrlen(p);
2636
2637 for (opt = optstart; opt != NULL &&
2638 opt < US (ipopt) + optlen;)
2639 {
2640 switch (*opt)
2641 {
2642 case IPOPT_EOL:
2643 opt = NULL;
2644 break;
2645
2646 case IPOPT_NOP:
2647 opt++;
2648 break;
2649
2650 case IPOPT_SSRR:
2651 case IPOPT_LSRR:
2652 if (!string_format(p, pend-p, " %s [@%s",
2653 (*opt == IPOPT_SSRR)? "SSRR" : "LSRR",
2654 #if OPTSTYLE == 1
2655 inet_ntoa(*((struct in_addr *)(&(ipopt->faddr))))))
2656 #elif OPTSTYLE == 2
2657 inet_ntoa(ipopt->ip_dst)))
2658 #else
2659 inet_ntoa(ipopt->ipopt_dst)))
2660 #endif
2661 {
2662 opt = NULL;
2663 break;
2664 }
2665
2666 p += Ustrlen(p);
2667 optcount = (opt[1] - 3) / sizeof(struct in_addr);
2668 adptr = opt + 3;
2669 while (optcount-- > 0)
2670 {
2671 memcpy(&addr, adptr, sizeof(addr));
2672 if (!string_format(p, pend - p - 1, "%s%s",
2673 (optcount == 0)? ":" : "@", inet_ntoa(addr)))
2674 {
2675 opt = NULL;
2676 break;
2677 }
2678 p += Ustrlen(p);
2679 adptr += sizeof(struct in_addr);
2680 }
2681 *p++ = ']';
2682 opt += opt[1];
2683 break;
2684
2685 default:
2686 {
2687 int i;
2688 if (pend - p < 4 + 3*opt[1]) { opt = NULL; break; }
2689 Ustrcat(p, "[ ");
2690 p += 2;
2691 for (i = 0; i < opt[1]; i++)
2692 p += sprintf(CS p, "%2.2x ", opt[i]);
2693 *p++ = ']';
2694 }
2695 opt += opt[1];
2696 break;
2697 }
2698 }
2699
2700 *p = 0;
2701 log_write(0, LOG_MAIN, "%s", big_buffer);
2702
2703 /* Refuse any call with IP options. This is what tcpwrappers 7.5 does. */
2704
2705 log_write(0, LOG_MAIN|LOG_REJECT,
2706 "connection from %s refused (IP options)", host_and_ident(FALSE));
2707
2708 smtp_printf("554 SMTP service not available\r\n", FALSE);
2709 return FALSE;
2710 }
2711
2712 /* Length of options = 0 => there are no options */
2713
2714 else DEBUG(D_receive) debug_printf("no IP options found\n");
2715 }
2716 #endif /* HAVE_IPV6 && !defined(NO_IP_OPTIONS) */
2717
2718 /* Set keep-alive in socket options. The option is on by default. This
2719 setting is an attempt to get rid of some hanging connections that stick in
2720 read() when the remote end (usually a dialup) goes away. */
2721
2722 if (smtp_accept_keepalive && !f.sender_host_notsocket)
2723 ip_keepalive(fileno(smtp_out), sender_host_address, FALSE);
2724
2725 /* If the current host matches host_lookup, set the name by doing a
2726 reverse lookup. On failure, sender_host_name will be NULL and
2727 host_lookup_failed will be TRUE. This may or may not be serious - optional
2728 checks later. */
2729
2730 if (verify_check_host(&host_lookup) == OK)
2731 {
2732 (void)host_name_lookup();
2733 host_build_sender_fullhost();
2734 }
2735
2736 /* Delay this until we have the full name, if it is looked up. */
2737
2738 set_process_info("handling incoming connection from %s",
2739 host_and_ident(FALSE));
2740
2741 /* Expand smtp_receive_timeout, if needed */
2742
2743 if (smtp_receive_timeout_s)
2744 {
2745 uschar * exp;
2746 if ( !(exp = expand_string(smtp_receive_timeout_s))
2747 || !(*exp)
2748 || (smtp_receive_timeout = readconf_readtime(exp, 0, FALSE)) < 0
2749 )
2750 log_write(0, LOG_MAIN|LOG_PANIC,
2751 "bad value for smtp_receive_timeout: '%s'", exp ? exp : US"");
2752 }
2753
2754 /* Test for explicit connection rejection */
2755
2756 if (verify_check_host(&host_reject_connection) == OK)
2757 {
2758 log_write(L_connection_reject, LOG_MAIN|LOG_REJECT, "refused connection "
2759 "from %s (host_reject_connection)", host_and_ident(FALSE));
2760 smtp_printf("554 SMTP service not available\r\n", FALSE);
2761 return FALSE;
2762 }
2763
2764 /* Test with TCP Wrappers if so configured. There is a problem in that
2765 hosts_ctl() returns 0 (deny) under a number of system failure circumstances,
2766 such as disks dying. In these cases, it is desirable to reject with a 4xx
2767 error instead of a 5xx error. There isn't a "right" way to detect such
2768 problems. The following kludge is used: errno is zeroed before calling
2769 hosts_ctl(). If the result is "reject", a 5xx error is given only if the
2770 value of errno is 0 or ENOENT (which happens if /etc/hosts.{allow,deny} does
2771 not exist). */
2772
2773 #ifdef USE_TCP_WRAPPERS
2774 errno = 0;
2775 if (!(tcp_wrappers_name = expand_string(tcp_wrappers_daemon_name)))
2776 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "Expansion of \"%s\" "
2777 "(tcp_wrappers_name) failed: %s", string_printing(tcp_wrappers_name),
2778 expand_string_message);
2779
2780 if (!hosts_ctl(tcp_wrappers_name,
2781 sender_host_name ? CS sender_host_name : STRING_UNKNOWN,
2782 sender_host_address ? CS sender_host_address : STRING_UNKNOWN,
2783 sender_ident ? CS sender_ident : STRING_UNKNOWN))
2784 {
2785 if (errno == 0 || errno == ENOENT)
2786 {
2787 HDEBUG(D_receive) debug_printf("tcp wrappers rejection\n");
2788 log_write(L_connection_reject,
2789 LOG_MAIN|LOG_REJECT, "refused connection from %s "
2790 "(tcp wrappers)", host_and_ident(FALSE));
2791 smtp_printf("554 SMTP service not available\r\n", FALSE);
2792 }
2793 else
2794 {
2795 int save_errno = errno;
2796 HDEBUG(D_receive) debug_printf("tcp wrappers rejected with unexpected "
2797 "errno value %d\n", save_errno);
2798 log_write(L_connection_reject,
2799 LOG_MAIN|LOG_REJECT, "temporarily refused connection from %s "
2800 "(tcp wrappers errno=%d)", host_and_ident(FALSE), save_errno);
2801 smtp_printf("451 Temporary local problem - please try later\r\n", FALSE);
2802 }
2803 return FALSE;
2804 }
2805 #endif
2806
2807 /* Check for reserved slots. The value of smtp_accept_count has already been
2808 incremented to include this process. */
2809
2810 if (smtp_accept_max > 0 &&
2811 smtp_accept_count > smtp_accept_max - smtp_accept_reserve)
2812 {
2813 if ((rc = verify_check_host(&smtp_reserve_hosts)) != OK)
2814 {
2815 log_write(L_connection_reject,
2816 LOG_MAIN, "temporarily refused connection from %s: not in "
2817 "reserve list: connected=%d max=%d reserve=%d%s",
2818 host_and_ident(FALSE), smtp_accept_count - 1, smtp_accept_max,
2819 smtp_accept_reserve, (rc == DEFER)? " (lookup deferred)" : "");
2820 smtp_printf("421 %s: Too many concurrent SMTP connections; "
2821 "please try again later\r\n", FALSE, smtp_active_hostname);
2822 return FALSE;
2823 }
2824 reserved_host = TRUE;
2825 }
2826
2827 /* If a load level above which only messages from reserved hosts are
2828 accepted is set, check the load. For incoming calls via the daemon, the
2829 check is done in the superior process if there are no reserved hosts, to
2830 save a fork. In all cases, the load average will already be available
2831 in a global variable at this point. */
2832
2833 if (smtp_load_reserve >= 0 &&
2834 load_average > smtp_load_reserve &&
2835 !reserved_host &&
2836 verify_check_host(&smtp_reserve_hosts) != OK)
2837 {
2838 log_write(L_connection_reject,
2839 LOG_MAIN, "temporarily refused connection from %s: not in "
2840 "reserve list and load average = %.2f", host_and_ident(FALSE),
2841 (double)load_average/1000.0);
2842 smtp_printf("421 %s: Too much load; please try again later\r\n", FALSE,
2843 smtp_active_hostname);
2844 return FALSE;
2845 }
2846
2847 /* Determine whether unqualified senders or recipients are permitted
2848 for this host. Unfortunately, we have to do this every time, in order to
2849 set the flags so that they can be inspected when considering qualifying
2850 addresses in the headers. For a site that permits no qualification, this
2851 won't take long, however. */
2852
2853 f.allow_unqualified_sender =
2854 verify_check_host(&sender_unqualified_hosts) == OK;
2855
2856 f.allow_unqualified_recipient =
2857 verify_check_host(&recipient_unqualified_hosts) == OK;
2858
2859 /* Determine whether HELO/EHLO is required for this host. The requirement
2860 can be hard or soft. */
2861
2862 helo_required = verify_check_host(&helo_verify_hosts) == OK;
2863 if (!helo_required)
2864 helo_verify = verify_check_host(&helo_try_verify_hosts) == OK;
2865
2866 /* Determine whether this hosts is permitted to send syntactic junk
2867 after a HELO or EHLO command. */
2868
2869 helo_accept_junk = verify_check_host(&helo_accept_junk_hosts) == OK;
2870 }
2871
2872 /* For batch SMTP input we are now done. */
2873
2874 if (smtp_batched_input) return TRUE;
2875
2876 /* If valid Proxy Protocol source is connecting, set up session.
2877 * Failure will not allow any SMTP function other than QUIT. */
2878
2879 #ifdef SUPPORT_PROXY
2880 proxy_session = FALSE;
2881 f.proxy_session_failed = FALSE;
2882 if (check_proxy_protocol_host())
2883 setup_proxy_protocol_host();
2884 #endif
2885
2886 /* Start up TLS if tls_on_connect is set. This is for supporting the legacy
2887 smtps port for use with older style SSL MTAs. */
2888
2889 #ifdef SUPPORT_TLS
2890 if (tls_in.on_connect)
2891 {
2892 if (tls_server_start(tls_require_ciphers, &user_msg) != OK)
2893 return smtp_log_tls_fail(user_msg);
2894 cmd_list[CMD_LIST_TLS_AUTH].is_mail_cmd = TRUE;
2895 }
2896 #endif
2897
2898 /* Run the connect ACL if it exists */
2899
2900 user_msg = NULL;
2901 if (acl_smtp_connect)
2902 {
2903 int rc;
2904 if ((rc = acl_check(ACL_WHERE_CONNECT, NULL, acl_smtp_connect, &user_msg,
2905 &log_msg)) != OK)
2906 {
2907 (void) smtp_handle_acl_fail(ACL_WHERE_CONNECT, rc, user_msg, log_msg);
2908 return FALSE;
2909 }
2910 }
2911
2912 /* Output the initial message for a two-way SMTP connection. It may contain
2913 newlines, which then cause a multi-line response to be given. */
2914
2915 code = US"220"; /* Default status code */
2916 esc = US""; /* Default extended status code */
2917 esclen = 0; /* Length of esc */
2918
2919 if (!user_msg)
2920 {
2921 if (!(s = expand_string(smtp_banner)))
2922 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "Expansion of \"%s\" (smtp_banner) "
2923 "failed: %s", smtp_banner, expand_string_message);
2924 }
2925 else
2926 {
2927 int codelen = 3;
2928 s = user_msg;
2929 smtp_message_code(&code, &codelen, &s, NULL, TRUE);
2930 if (codelen > 4)
2931 {
2932 esc = code + 4;
2933 esclen = codelen - 4;
2934 }
2935 }
2936
2937 /* Remove any terminating newlines; might as well remove trailing space too */
2938
2939 p = s + Ustrlen(s);
2940 while (p > s && isspace(p[-1])) p--;
2941 *p = 0;
2942
2943 /* It seems that CC:Mail is braindead, and assumes that the greeting message
2944 is all contained in a single IP packet. The original code wrote out the
2945 greeting using several calls to fprint/fputc, and on busy servers this could
2946 cause it to be split over more than one packet - which caused CC:Mail to fall
2947 over when it got the second part of the greeting after sending its first
2948 command. Sigh. To try to avoid this, build the complete greeting message
2949 first, and output it in one fell swoop. This gives a better chance of it
2950 ending up as a single packet. */
2951
2952 ss = string_get(256);
2953
2954 p = s;
2955 do /* At least once, in case we have an empty string */
2956 {
2957 int len;
2958 uschar *linebreak = Ustrchr(p, '\n');
2959 ss = string_catn(ss, code, 3);
2960 if (!linebreak)
2961 {
2962 len = Ustrlen(p);
2963 ss = string_catn(ss, US" ", 1);
2964 }
2965 else
2966 {
2967 len = linebreak - p;
2968 ss = string_catn(ss, US"-", 1);
2969 }
2970 ss = string_catn(ss, esc, esclen);
2971 ss = string_catn(ss, p, len);
2972 ss = string_catn(ss, US"\r\n", 2);
2973 p += len;
2974 if (linebreak) p++;
2975 }
2976 while (*p);
2977
2978 /* Before we write the banner, check that there is no input pending, unless
2979 this synchronisation check is disabled. */
2980
2981 if (!check_sync())
2982 {
2983 unsigned n = smtp_inend - smtp_inptr;
2984 if (n > 32) n = 32;
2985
2986 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP protocol "
2987 "synchronization error (input sent without waiting for greeting): "
2988 "rejected connection from %s input=\"%s\"", host_and_ident(TRUE),
2989 string_printing(string_copyn(smtp_inptr, n)));
2990 smtp_printf("554 SMTP synchronization error\r\n", FALSE);
2991 return FALSE;
2992 }
2993
2994 /* Now output the banner */
2995
2996 smtp_printf("%s", FALSE, string_from_gstring(ss));
2997
2998 /* Attempt to see if we sent the banner before the last ACK of the 3-way
2999 handshake arrived. If so we must have managed a TFO. */
3000
3001 #ifdef TCP_FASTOPEN
3002 tfo_in_check();
3003 #endif
3004
3005 return TRUE;
3006 }
3007
3008
3009
3010
3011
3012 /*************************************************
3013 * Handle SMTP syntax and protocol errors *
3014 *************************************************/
3015
3016 /* Write to the log for SMTP syntax errors in incoming commands, if configured
3017 to do so. Then transmit the error response. The return value depends on the
3018 number of syntax and protocol errors in this SMTP session.
3019
3020 Arguments:
3021 type error type, given as a log flag bit
3022 code response code; <= 0 means don't send a response
3023 data data to reflect in the response (can be NULL)
3024 errmess the error message
3025
3026 Returns: -1 limit of syntax/protocol errors NOT exceeded
3027 +1 limit of syntax/protocol errors IS exceeded
3028
3029 These values fit in with the values of the "done" variable in the main
3030 processing loop in smtp_setup_msg(). */
3031
3032 static int
3033 synprot_error(int type, int code, uschar *data, uschar *errmess)
3034 {
3035 int yield = -1;
3036
3037 log_write(type, LOG_MAIN, "SMTP %s error in \"%s\" %s %s",
3038 (type == L_smtp_syntax_error)? "syntax" : "protocol",
3039 string_printing(smtp_cmd_buffer), host_and_ident(TRUE), errmess);
3040
3041 if (++synprot_error_count > smtp_max_synprot_errors)
3042 {
3043 yield = 1;
3044 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
3045 "syntax or protocol errors (last command was \"%s\")",
3046 host_and_ident(FALSE), string_printing(smtp_cmd_buffer));
3047 }
3048
3049 if (code > 0)
3050 {
3051 smtp_printf("%d%c%s%s%s\r\n", FALSE, code, yield == 1 ? '-' : ' ',
3052 data ? data : US"", data ? US": " : US"", errmess);
3053 if (yield == 1)
3054 smtp_printf("%d Too many syntax or protocol errors\r\n", FALSE, code);
3055 }
3056
3057 return yield;
3058 }
3059
3060
3061
3062
3063 /*************************************************
3064 * Send SMTP response, possibly multiline *
3065 *************************************************/
3066
3067 /* There are, it seems, broken clients out there that cannot handle multiline
3068 responses. If no_multiline_responses is TRUE (it can be set from an ACL), we
3069 output nothing for non-final calls, and only the first line for anything else.
3070
3071 Arguments:
3072 code SMTP code, may involve extended status codes
3073 codelen length of smtp code; if > 4 there's an ESC
3074 final FALSE if the last line isn't the final line
3075 msg message text, possibly containing newlines
3076
3077 Returns: nothing
3078 */
3079
3080 void
3081 smtp_respond(uschar* code, int codelen, BOOL final, uschar *msg)
3082 {
3083 int esclen = 0;
3084 uschar *esc = US"";
3085
3086 if (!final && f.no_multiline_responses) return;
3087
3088 if (codelen > 4)
3089 {
3090 esc = code + 4;
3091 esclen = codelen - 4;
3092 }
3093
3094 /* If this is the first output for a (non-batch) RCPT command, see if all RCPTs
3095 have had the same. Note: this code is also present in smtp_printf(). It would
3096 be tidier to have it only in one place, but when it was added, it was easier to
3097 do it that way, so as not to have to mess with the code for the RCPT command,
3098 which sometimes uses smtp_printf() and sometimes smtp_respond(). */
3099
3100 if (rcpt_in_progress)
3101 {
3102 if (rcpt_smtp_response == NULL)
3103 rcpt_smtp_response = string_copy(msg);
3104 else if (rcpt_smtp_response_same &&
3105 Ustrcmp(rcpt_smtp_response, msg) != 0)
3106 rcpt_smtp_response_same = FALSE;
3107 rcpt_in_progress = FALSE;
3108 }
3109
3110 /* Now output the message, splitting it up into multiple lines if necessary.
3111 We only handle pipelining these responses as far as nonfinal/final groups,
3112 not the whole MAIL/RCPT/DATA response set. */
3113
3114 for (;;)
3115 {
3116 uschar *nl = Ustrchr(msg, '\n');
3117 if (nl == NULL)
3118 {
3119 smtp_printf("%.3s%c%.*s%s\r\n", !final, code, final ? ' ':'-', esclen, esc, msg);
3120 return;
3121 }
3122 else if (nl[1] == 0 || f.no_multiline_responses)
3123 {
3124 smtp_printf("%.3s%c%.*s%.*s\r\n", !final, code, final ? ' ':'-', esclen, esc,
3125 (int)(nl - msg), msg);
3126 return;
3127 }
3128 else
3129 {
3130 smtp_printf("%.3s-%.*s%.*s\r\n", TRUE, code, esclen, esc, (int)(nl - msg), msg);
3131 msg = nl + 1;
3132 while (isspace(*msg)) msg++;
3133 }
3134 }
3135 }
3136
3137
3138
3139
3140 /*************************************************
3141 * Parse user SMTP message *
3142 *************************************************/
3143
3144 /* This function allows for user messages overriding the response code details
3145 by providing a suitable response code string at the start of the message
3146 user_msg. Check the message for starting with a response code and optionally an
3147 extended status code. If found, check that the first digit is valid, and if so,
3148 change the code pointer and length to use the replacement. An invalid code
3149 causes a panic log; in this case, if the log messages is the same as the user
3150 message, we must also adjust the value of the log message to show the code that
3151 is actually going to be used (the original one).
3152
3153 This function is global because it is called from receive.c as well as within
3154 this module.
3155
3156 Note that the code length returned includes the terminating whitespace
3157 character, which is always included in the regex match.
3158
3159 Arguments:
3160 code SMTP code, may involve extended status codes
3161 codelen length of smtp code; if > 4 there's an ESC
3162 msg message text
3163 log_msg optional log message, to be adjusted with the new SMTP code
3164 check_valid if true, verify the response code
3165
3166 Returns: nothing
3167 */
3168
3169 void
3170 smtp_message_code(uschar **code, int *codelen, uschar **msg, uschar **log_msg,
3171 BOOL check_valid)
3172 {
3173 int n;
3174 int ovector[3];
3175
3176 if (!msg || !*msg) return;
3177
3178 if ((n = pcre_exec(regex_smtp_code, NULL, CS *msg, Ustrlen(*msg), 0,
3179 PCRE_EOPT, ovector, sizeof(ovector)/sizeof(int))) < 0) return;
3180
3181 if (check_valid && (*msg)[0] != (*code)[0])
3182 {
3183 log_write(0, LOG_MAIN|LOG_PANIC, "configured error code starts with "
3184 "incorrect digit (expected %c) in \"%s\"", (*code)[0], *msg);
3185 if (log_msg != NULL && *log_msg == *msg)
3186 *log_msg = string_sprintf("%s %s", *code, *log_msg + ovector[1]);
3187 }
3188 else
3189 {
3190 *code = *msg;
3191 *codelen = ovector[1]; /* Includes final space */
3192 }
3193 *msg += ovector[1]; /* Chop the code off the message */
3194 return;
3195 }
3196
3197
3198
3199
3200 /*************************************************
3201 * Handle an ACL failure *
3202 *************************************************/
3203
3204 /* This function is called when acl_check() fails. As well as calls from within
3205 this module, it is called from receive.c for an ACL after DATA. It sorts out
3206 logging the incident, and sends the error response. A message containing
3207 newlines is turned into a multiline SMTP response, but for logging, only the
3208 first line is used.
3209
3210 There's a table of default permanent failure response codes to use in
3211 globals.c, along with the table of names. VFRY is special. Despite RFC1123 it
3212 defaults disabled in Exim. However, discussion in connection with RFC 821bis
3213 (aka RFC 2821) has concluded that the response should be 252 in the disabled
3214 state, because there are broken clients that try VRFY before RCPT. A 5xx
3215 response should be given only when the address is positively known to be
3216 undeliverable. Sigh. We return 252 if there is no VRFY ACL or it provides
3217 no explicit code, but if there is one we let it know best.
3218 Also, for ETRN, 458 is given on refusal, and for AUTH, 503.
3219
3220 From Exim 4.63, it is possible to override the response code details by
3221 providing a suitable response code string at the start of the message provided
3222 in user_msg. The code's first digit is checked for validity.
3223
3224 Arguments:
3225 where where the ACL was called from
3226 rc the failure code
3227 user_msg a message that can be included in an SMTP response
3228 log_msg a message for logging
3229
3230 Returns: 0 in most cases
3231 2 if the failure code was FAIL_DROP, in which case the
3232 SMTP connection should be dropped (this value fits with the
3233 "done" variable in smtp_setup_msg() below)
3234 */
3235
3236 int
3237 smtp_handle_acl_fail(int where, int rc, uschar *user_msg, uschar *log_msg)
3238 {
3239 BOOL drop = rc == FAIL_DROP;
3240 int codelen = 3;
3241 uschar *smtp_code;
3242 uschar *lognl;
3243 uschar *sender_info = US"";
3244 uschar *what =
3245 #ifdef WITH_CONTENT_SCAN
3246 where == ACL_WHERE_MIME ? US"during MIME ACL checks" :
3247 #endif
3248 where == ACL_WHERE_PREDATA ? US"DATA" :
3249 where == ACL_WHERE_DATA ? US"after DATA" :
3250 #ifndef DISABLE_PRDR
3251 where == ACL_WHERE_PRDR ? US"after DATA PRDR" :
3252 #endif
3253 smtp_cmd_data ?
3254 string_sprintf("%s %s", acl_wherenames[where], smtp_cmd_data) :
3255 string_sprintf("%s in \"connect\" ACL", acl_wherenames[where]);
3256
3257 if (drop) rc = FAIL;
3258
3259 /* Set the default SMTP code, and allow a user message to change it. */
3260
3261 smtp_code = rc == FAIL ? acl_wherecodes[where] : US"451";
3262 smtp_message_code(&smtp_code, &codelen, &user_msg, &log_msg,
3263 where != ACL_WHERE_VRFY);
3264
3265 /* We used to have sender_address here; however, there was a bug that was not
3266 updating sender_address after a rewrite during a verify. When this bug was
3267 fixed, sender_address at this point became the rewritten address. I'm not sure
3268 this is what should be logged, so I've changed to logging the unrewritten
3269 address to retain backward compatibility. */
3270
3271 #ifndef WITH_CONTENT_SCAN
3272 if (where == ACL_WHERE_RCPT || where == ACL_WHERE_DATA)
3273 #else
3274 if (where == ACL_WHERE_RCPT || where == ACL_WHERE_DATA || where == ACL_WHERE_MIME)
3275 #endif
3276 {
3277 sender_info = string_sprintf("F=<%s>%s%s%s%s ",
3278 sender_address_unrewritten ? sender_address_unrewritten : sender_address,
3279 sender_host_authenticated ? US" A=" : US"",
3280 sender_host_authenticated ? sender_host_authenticated : US"",
3281 sender_host_authenticated && authenticated_id ? US":" : US"",
3282 sender_host_authenticated && authenticated_id ? authenticated_id : US""
3283 );
3284 }
3285
3286 /* If there's been a sender verification failure with a specific message, and
3287 we have not sent a response about it yet, do so now, as a preliminary line for
3288 failures, but not defers. However, always log it for defer, and log it for fail
3289 unless the sender_verify_fail log selector has been turned off. */
3290
3291 if (sender_verified_failed &&
3292 !testflag(sender_verified_failed, af_sverify_told))
3293 {
3294 BOOL save_rcpt_in_progress = rcpt_in_progress;
3295 rcpt_in_progress = FALSE; /* So as not to treat these as the error */
3296
3297 setflag(sender_verified_failed, af_sverify_told);
3298
3299 if (rc != FAIL || LOGGING(sender_verify_fail))
3300 log_write(0, LOG_MAIN|LOG_REJECT, "%s sender verify %s for <%s>%s",
3301 host_and_ident(TRUE),
3302 ((sender_verified_failed->special_action & 255) == DEFER)? "defer":"fail",
3303 sender_verified_failed->address,
3304 (sender_verified_failed->message == NULL)? US"" :
3305 string_sprintf(": %s", sender_verified_failed->message));
3306
3307 if (rc == FAIL && sender_verified_failed->user_message)
3308 smtp_respond(smtp_code, codelen, FALSE, string_sprintf(
3309 testflag(sender_verified_failed, af_verify_pmfail)?
3310 "Postmaster verification failed while checking <%s>\n%s\n"
3311 "Several RFCs state that you are required to have a postmaster\n"
3312 "mailbox for each mail domain. This host does not accept mail\n"
3313 "from domains whose servers reject the postmaster address."
3314 :
3315 testflag(sender_verified_failed, af_verify_nsfail)?
3316 "Callback setup failed while verifying <%s>\n%s\n"
3317 "The initial connection, or a HELO or MAIL FROM:<> command was\n"
3318 "rejected. Refusing MAIL FROM:<> does not help fight spam, disregards\n"
3319 "RFC requirements, and stops you from receiving standard bounce\n"
3320 "messages. This host does not accept mail from domains whose servers\n"
3321 "refuse bounces."
3322 :
3323 "Verification failed for <%s>\n%s",
3324 sender_verified_failed->address,
3325 sender_verified_failed->user_message));
3326
3327 rcpt_in_progress = save_rcpt_in_progress;
3328 }
3329
3330 /* Sort out text for logging */
3331
3332 log_msg = log_msg ? string_sprintf(": %s", log_msg) : US"";
3333 if ((lognl = Ustrchr(log_msg, '\n'))) *lognl = 0;
3334
3335 /* Send permanent failure response to the command, but the code used isn't
3336 always a 5xx one - see comments at the start of this function. If the original
3337 rc was FAIL_DROP we drop the connection and yield 2. */
3338
3339 if (rc == FAIL)
3340 smtp_respond(smtp_code, codelen, TRUE,
3341 user_msg ? user_msg : US"Administrative prohibition");
3342
3343 /* Send temporary failure response to the command. Don't give any details,
3344 unless acl_temp_details is set. This is TRUE for a callout defer, a "defer"
3345 verb, and for a header verify when smtp_return_error_details is set.
3346
3347 This conditional logic is all somewhat of a mess because of the odd
3348 interactions between temp_details and return_error_details. One day it should
3349 be re-implemented in a tidier fashion. */
3350
3351 else
3352 if (f.acl_temp_details && user_msg)
3353 {
3354 if ( smtp_return_error_details
3355 && sender_verified_failed
3356 && sender_verified_failed->message
3357 )
3358 smtp_respond(smtp_code, codelen, FALSE, sender_verified_failed->message);
3359
3360 smtp_respond(smtp_code, codelen, TRUE, user_msg);
3361 }
3362 else
3363 smtp_respond(smtp_code, codelen, TRUE,
3364 US"Temporary local problem - please try later");
3365
3366 /* Log the incident to the logs that are specified by log_reject_target
3367 (default main, reject). This can be empty to suppress logging of rejections. If
3368 the connection is not forcibly to be dropped, return 0. Otherwise, log why it
3369 is closing if required and return 2. */
3370
3371 if (log_reject_target != 0)
3372 {
3373 #ifdef SUPPORT_TLS
3374 gstring * g = s_tlslog(NULL);
3375 uschar * tls = string_from_gstring(g);
3376 if (!tls) tls = US"";
3377 #else
3378 uschar * tls = US"";
3379 #endif
3380 log_write(where == ACL_WHERE_CONNECT ? L_connection_reject : 0,
3381 log_reject_target, "%s%s%s %s%srejected %s%s",
3382 LOGGING(dnssec) && sender_host_dnssec ? US" DS" : US"",
3383 host_and_ident(TRUE),
3384 tls,
3385 sender_info,
3386 rc == FAIL ? US"" : US"temporarily ",
3387 what, log_msg);
3388 }
3389
3390 if (!drop) return 0;
3391
3392 log_write(L_smtp_connection, LOG_MAIN, "%s closed by DROP in ACL",
3393 smtp_get_connection_info());
3394
3395 /* Run the not-quit ACL, but without any custom messages. This should not be a
3396 problem, because we get here only if some other ACL has issued "drop", and
3397 in that case, *its* custom messages will have been used above. */
3398
3399 smtp_notquit_exit(US"acl-drop", NULL, NULL);
3400 return 2;
3401 }
3402
3403
3404
3405
3406 /*************************************************
3407 * Handle SMTP exit when QUIT is not given *
3408 *************************************************/
3409
3410 /* This function provides a logging/statistics hook for when an SMTP connection
3411 is dropped on the floor or the other end goes away. It's a global function
3412 because it's called from receive.c as well as this module. As well as running
3413 the NOTQUIT ACL, if there is one, this function also outputs a final SMTP
3414 response, either with a custom message from the ACL, or using a default. There
3415 is one case, however, when no message is output - after "drop". In that case,
3416 the ACL that obeyed "drop" has already supplied the custom message, and NULL is
3417 passed to this function.
3418
3419 In case things go wrong while processing this function, causing an error that
3420 may re-enter this function, there is a recursion check.
3421
3422 Arguments:
3423 reason What $smtp_notquit_reason will be set to in the ACL;
3424 if NULL, the ACL is not run
3425 code The error code to return as part of the response
3426 defaultrespond The default message if there's no user_msg
3427
3428 Returns: Nothing
3429 */
3430
3431 void
3432 smtp_notquit_exit(uschar *reason, uschar *code, uschar *defaultrespond, ...)
3433 {
3434 int rc;
3435 uschar *user_msg = NULL;
3436 uschar *log_msg = NULL;
3437
3438 /* Check for recursive acll */
3439
3440 if (smtp_exit_function_called)
3441 {
3442 log_write(0, LOG_PANIC, "smtp_notquit_exit() called more than once (%s)",
3443 reason);
3444 return;
3445 }
3446 smtp_exit_function_called = TRUE;
3447
3448 /* Call the not-QUIT ACL, if there is one, unless no reason is given. */
3449
3450 if (acl_smtp_notquit && reason)
3451 {
3452 smtp_notquit_reason = reason;
3453 if ((rc = acl_check(ACL_WHERE_NOTQUIT, NULL, acl_smtp_notquit, &user_msg,
3454 &log_msg)) == ERROR)
3455 log_write(0, LOG_MAIN|LOG_PANIC, "ACL for not-QUIT returned ERROR: %s",
3456 log_msg);
3457 }
3458
3459 /* Write an SMTP response if we are expected to give one. As the default
3460 responses are all internal, they should always fit in the buffer, but code a
3461 warning, just in case. Note that string_vformat() still leaves a complete
3462 string, even if it is incomplete. */
3463
3464 if (code && defaultrespond)
3465 {
3466 if (user_msg)
3467 smtp_respond(code, 3, TRUE, user_msg);
3468 else
3469 {
3470 uschar buffer[128];
3471 va_list ap;
3472 va_start(ap, defaultrespond);
3473 if (!string_vformat(buffer, sizeof(buffer), CS defaultrespond, ap))
3474 log_write(0, LOG_MAIN|LOG_PANIC, "string too large in smtp_notquit_exit()");
3475 smtp_printf("%s %s\r\n", FALSE, code, buffer);
3476 va_end(ap);
3477 }
3478 mac_smtp_fflush();
3479 }
3480 }
3481
3482
3483
3484
3485 /*************************************************
3486 * Verify HELO argument *
3487 *************************************************/
3488
3489 /* This function is called if helo_verify_hosts or helo_try_verify_hosts is
3490 matched. It is also called from ACL processing if verify = helo is used and
3491 verification was not previously tried (i.e. helo_try_verify_hosts was not
3492 matched). The result of its processing is to set helo_verified and
3493 helo_verify_failed. These variables should both be FALSE for this function to
3494 be called.
3495
3496 Note that EHLO/HELO is legitimately allowed to quote an address literal. Allow
3497 for IPv6 ::ffff: literals.
3498
3499 Argument: none
3500 Returns: TRUE if testing was completed;
3501 FALSE on a temporary failure
3502 */
3503
3504 BOOL
3505 smtp_verify_helo(void)
3506 {
3507 BOOL yield = TRUE;
3508
3509 HDEBUG(D_receive) debug_printf("verifying EHLO/HELO argument \"%s\"\n",
3510 sender_helo_name);
3511
3512 if (sender_helo_name == NULL)
3513 {
3514 HDEBUG(D_receive) debug_printf("no EHLO/HELO command was issued\n");
3515 }
3516
3517 /* Deal with the case of -bs without an IP address */
3518
3519 else if (sender_host_address == NULL)
3520 {
3521 HDEBUG(D_receive) debug_printf("no client IP address: assume success\n");
3522 f.helo_verified = TRUE;
3523 }
3524
3525 /* Deal with the more common case when there is a sending IP address */
3526
3527 else if (sender_helo_name[0] == '[')
3528 {
3529 f.helo_verified = Ustrncmp(sender_helo_name+1, sender_host_address,
3530 Ustrlen(sender_host_address)) == 0;
3531
3532 #if HAVE_IPV6
3533 if (!f.helo_verified)
3534 {
3535 if (strncmpic(sender_host_address, US"::ffff:", 7) == 0)
3536 f.helo_verified = Ustrncmp(sender_helo_name + 1,
3537 sender_host_address + 7, Ustrlen(sender_host_address) - 7) == 0;
3538 }
3539 #endif
3540
3541 HDEBUG(D_receive)
3542 { if (f.helo_verified) debug_printf("matched host address\n"); }
3543 }
3544
3545 /* Do a reverse lookup if one hasn't already given a positive or negative
3546 response. If that fails, or the name doesn't match, try checking with a forward
3547 lookup. */
3548
3549 else
3550 {
3551 if (sender_host_name == NULL && !host_lookup_failed)
3552 yield = host_name_lookup() != DEFER;
3553
3554 /* If a host name is known, check it and all its aliases. */
3555
3556 if (sender_host_name)
3557 if ((f.helo_verified = strcmpic(sender_host_name, sender_helo_name) == 0))
3558 {
3559 sender_helo_dnssec = sender_host_dnssec;
3560 HDEBUG(D_receive) debug_printf("matched host name\n");
3561 }
3562 else
3563 {
3564 uschar **aliases = sender_host_aliases;
3565 while (*aliases)
3566 if ((f.helo_verified = strcmpic(*aliases++, sender_helo_name) == 0))
3567 {
3568 sender_helo_dnssec = sender_host_dnssec;
3569 break;
3570 }
3571
3572 HDEBUG(D_receive) if (f.helo_verified)
3573 debug_printf("matched alias %s\n", *(--aliases));
3574 }
3575
3576 /* Final attempt: try a forward lookup of the helo name */
3577
3578 if (!f.helo_verified)
3579 {
3580 int rc;
3581 host_item h;
3582 dnssec_domains d;
3583 host_item *hh;
3584
3585 h.name = sender_helo_name;
3586 h.address = NULL;
3587 h.mx = MX_NONE;
3588 h.next = NULL;
3589 d.request = US"*";
3590 d.require = US"";
3591
3592 HDEBUG(D_receive) debug_printf("getting IP address for %s\n",
3593 sender_helo_name);
3594 rc = host_find_bydns(&h, NULL, HOST_FIND_BY_A | HOST_FIND_BY_AAAA,
3595 NULL, NULL, NULL, &d, NULL, NULL);
3596 if (rc == HOST_FOUND || rc == HOST_FOUND_LOCAL)
3597 for (hh = &h; hh; hh = hh->next)
3598 if (Ustrcmp(hh->address, sender_host_address) == 0)
3599 {
3600 f.helo_verified = TRUE;
3601 if (h.dnssec == DS_YES) sender_helo_dnssec = TRUE;
3602 HDEBUG(D_receive)
3603 {
3604 debug_printf("IP address for %s matches calling address\n"
3605 "Forward DNS security status: %sverified\n",
3606 sender_helo_name, sender_helo_dnssec ? "" : "un");
3607 }
3608 break;
3609 }
3610 }
3611 }
3612
3613 if (!f.helo_verified) f.helo_verify_failed = TRUE; /* We've tried ... */
3614 return yield;
3615 }
3616
3617
3618
3619
3620 /*************************************************
3621 * Send user response message *
3622 *************************************************/
3623
3624 /* This function is passed a default response code and a user message. It calls
3625 smtp_message_code() to check and possibly modify the response code, and then
3626 calls smtp_respond() to transmit the response. I put this into a function
3627 just to avoid a lot of repetition.
3628
3629 Arguments:
3630 code the response code
3631 user_msg the user message
3632
3633 Returns: nothing
3634 */
3635
3636 static void
3637 smtp_user_msg(uschar *code, uschar *user_msg)
3638 {
3639 int len = 3;
3640 smtp_message_code(&code, &len, &user_msg, NULL, TRUE);
3641 smtp_respond(code, len, TRUE, user_msg);
3642 }
3643
3644
3645
3646 static int
3647 smtp_in_auth(auth_instance *au, uschar ** s, uschar ** ss)
3648 {
3649 const uschar *set_id = NULL;
3650 int rc, i;
3651
3652 /* Run the checking code, passing the remainder of the command line as
3653 data. Initials the $auth<n> variables as empty. Initialize $0 empty and set
3654 it as the only set numerical variable. The authenticator may set $auth<n>
3655 and also set other numeric variables. The $auth<n> variables are preferred
3656 nowadays; the numerical variables remain for backwards compatibility.
3657
3658 Afterwards, have a go at expanding the set_id string, even if
3659 authentication failed - for bad passwords it can be useful to log the
3660 userid. On success, require set_id to expand and exist, and put it in
3661 authenticated_id. Save this in permanent store, as the working store gets
3662 reset at HELO, RSET, etc. */
3663
3664 for (i = 0; i < AUTH_VARS; i++) auth_vars[i] = NULL;
3665 expand_nmax = 0;
3666 expand_nlength[0] = 0; /* $0 contains nothing */
3667
3668 rc = (au->info->servercode)(au, smtp_cmd_data);
3669 if (au->set_id) set_id = expand_string(au->set_id);
3670 expand_nmax = -1; /* Reset numeric variables */
3671 for (i = 0; i < AUTH_VARS; i++) auth_vars[i] = NULL; /* Reset $auth<n> */
3672
3673 /* The value of authenticated_id is stored in the spool file and printed in
3674 log lines. It must not contain binary zeros or newline characters. In
3675 normal use, it never will, but when playing around or testing, this error
3676 can (did) happen. To guard against this, ensure that the id contains only
3677 printing characters. */
3678
3679 if (set_id) set_id = string_printing(set_id);
3680
3681 /* For the non-OK cases, set up additional logging data if set_id
3682 is not empty. */
3683
3684 if (rc != OK)
3685 set_id = set_id && *set_id
3686 ? string_sprintf(" (set_id=%s)", set_id) : US"";
3687
3688 /* Switch on the result */
3689
3690 switch(rc)
3691 {
3692 case OK:
3693 if (!au->set_id || set_id) /* Complete success */
3694 {
3695 if (set_id) authenticated_id = string_copy_malloc(set_id);
3696 sender_host_authenticated = au->name;
3697 sender_host_auth_pubname = au->public_name;
3698 authentication_failed = FALSE;
3699 authenticated_fail_id = NULL; /* Impossible to already be set? */
3700
3701 received_protocol =
3702 (sender_host_address ? protocols : protocols_local)
3703 [pextend + pauthed + (tls_in.active.sock >= 0 ? pcrpted:0)];
3704 *s = *ss = US"235 Authentication succeeded";
3705 authenticated_by = au;
3706 break;
3707 }
3708
3709 /* Authentication succeeded, but we failed to expand the set_id string.
3710 Treat this as a temporary error. */
3711
3712 auth_defer_msg = expand_string_message;
3713 /* Fall through */
3714
3715 case DEFER:
3716 if (set_id) authenticated_fail_id = string_copy_malloc(set_id);
3717 *s = string_sprintf("435 Unable to authenticate at present%s",
3718 auth_defer_user_msg);
3719 *ss = string_sprintf("435 Unable to authenticate at present%s: %s",
3720 set_id, auth_defer_msg);
3721 break;
3722
3723 case BAD64:
3724 *s = *ss = US"501 Invalid base64 data";
3725 break;
3726
3727 case CANCELLED:
3728 *s = *ss = US"501 Authentication cancelled";
3729 break;
3730
3731 case UNEXPECTED:
3732 *s = *ss = US"553 Initial data not expected";
3733 break;
3734
3735 case FAIL:
3736 if (set_id) authenticated_fail_id = string_copy_malloc(set_id);
3737 *s = US"535 Incorrect authentication data";
3738 *ss = string_sprintf("535 Incorrect authentication data%s", set_id);
3739 break;
3740
3741 default:
3742 if (set_id) authenticated_fail_id = string_copy_malloc(set_id);
3743 *s = US"435 Internal error";
3744 *ss = string_sprintf("435 Internal error%s: return %d from authentication "
3745 "check", set_id, rc);
3746 break;
3747 }
3748
3749 return rc;
3750 }
3751
3752
3753
3754
3755
3756 static int
3757 qualify_recipient(uschar ** recipient, uschar * smtp_cmd_data, uschar * tag)
3758 {
3759 int rd;
3760 if (f.allow_unqualified_recipient || strcmpic(*recipient, US"postmaster") == 0)
3761 {
3762 DEBUG(D_receive) debug_printf("unqualified address %s accepted\n",
3763 *recipient);
3764 rd = Ustrlen(recipient) + 1;
3765 *recipient = rewrite_address_qualify(*recipient, TRUE);
3766 return rd;
3767 }
3768 smtp_printf("501 %s: recipient address must contain a domain\r\n", FALSE,
3769 smtp_cmd_data);
3770 log_write(L_smtp_syntax_error,
3771 LOG_MAIN|LOG_REJECT, "unqualified %s rejected: <%s> %s%s",
3772 tag, *recipient, host_and_ident(TRUE), host_lookup_msg);
3773 return 0;
3774 }
3775
3776
3777
3778
3779 static void
3780 smtp_quit_handler(uschar ** user_msgp, uschar ** log_msgp)
3781 {
3782 HAD(SCH_QUIT);
3783 incomplete_transaction_log(US"QUIT");
3784 if (acl_smtp_quit)
3785 {
3786 int rc = acl_check(ACL_WHERE_QUIT, NULL, acl_smtp_quit, user_msgp, log_msgp);
3787 if (rc == ERROR)
3788 log_write(0, LOG_MAIN|LOG_PANIC, "ACL for QUIT returned ERROR: %s",
3789 *log_msgp);
3790 }
3791 if (*user_msgp)
3792 smtp_respond(US"221", 3, TRUE, *user_msgp);
3793 else
3794 smtp_printf("221 %s closing connection\r\n", FALSE, smtp_active_hostname);
3795
3796 #ifdef SUPPORT_TLS
3797 tls_close(NULL, TLS_SHUTDOWN_NOWAIT);
3798 #endif
3799
3800 log_write(L_smtp_connection, LOG_MAIN, "%s closed by QUIT",
3801 smtp_get_connection_info());
3802 }
3803
3804
3805 static void
3806 smtp_rset_handler(void)
3807 {
3808 HAD(SCH_RSET);
3809 incomplete_transaction_log(US"RSET");
3810 smtp_printf("250 Reset OK\r\n", FALSE);
3811 cmd_list[CMD_LIST_RSET].is_mail_cmd = FALSE;
3812 }
3813
3814
3815
3816 /*************************************************
3817 * Initialize for SMTP incoming message *
3818 *************************************************/
3819
3820 /* This function conducts the initial dialogue at the start of an incoming SMTP
3821 message, and builds a list of recipients. However, if the incoming message
3822 is part of a batch (-bS option) a separate function is called since it would
3823 be messy having tests splattered about all over this function. This function
3824 therefore handles the case where interaction is occurring. The input and output
3825 files are set up in smtp_in and smtp_out.
3826
3827 The global recipients_list is set to point to a vector of recipient_item
3828 blocks, whose number is given by recipients_count. This is extended by the
3829 receive_add_recipient() function. The global variable sender_address is set to
3830 the sender's address. The yield is +1 if a message has been successfully
3831 started, 0 if a QUIT command was encountered or the connection was refused from
3832 the particular host, or -1 if the connection was lost.
3833
3834 Argument: none
3835
3836 Returns: > 0 message successfully started (reached DATA)
3837 = 0 QUIT read or end of file reached or call refused
3838 < 0 lost connection
3839 */
3840
3841 int
3842 smtp_setup_msg(void)
3843 {
3844 int done = 0;
3845 BOOL toomany = FALSE;
3846 BOOL discarded = FALSE;
3847 BOOL last_was_rej_mail = FALSE;
3848 BOOL last_was_rcpt = FALSE;
3849 void *reset_point = store_get(0);
3850
3851 DEBUG(D_receive) debug_printf("smtp_setup_msg entered\n");
3852
3853 /* Reset for start of new message. We allow one RSET not to be counted as a
3854 nonmail command, for those MTAs that insist on sending it between every
3855 message. Ditto for EHLO/HELO and for STARTTLS, to allow for going in and out of
3856 TLS between messages (an Exim client may do this if it has messages queued up
3857 for the host). Note: we do NOT reset AUTH at this point. */
3858
3859 smtp_reset(reset_point);
3860 message_ended = END_NOTSTARTED;
3861
3862 chunking_state = f.chunking_offered ? CHUNKING_OFFERED : CHUNKING_NOT_OFFERED;
3863
3864 cmd_list[CMD_LIST_RSET].is_mail_cmd = TRUE;
3865 cmd_list[CMD_LIST_HELO].is_mail_cmd = TRUE;
3866 cmd_list[CMD_LIST_EHLO].is_mail_cmd = TRUE;
3867 #ifdef SUPPORT_TLS
3868 cmd_list[CMD_LIST_STARTTLS].is_mail_cmd = TRUE;
3869 #endif
3870
3871 /* Set the local signal handler for SIGTERM - it tries to end off tidily */
3872
3873 had_command_sigterm = 0;
3874 os_non_restarting_signal(SIGTERM, command_sigterm_handler);
3875
3876 /* Batched SMTP is handled in a different function. */
3877
3878 if (smtp_batched_input) return smtp_setup_batch_msg();
3879
3880 /* Deal with SMTP commands. This loop is exited by setting done to a POSITIVE
3881 value. The values are 2 larger than the required yield of the function. */
3882
3883 while (done <= 0)
3884 {
3885 const uschar **argv;
3886 uschar *etrn_command;
3887 uschar *etrn_serialize_key;
3888 uschar *errmess;
3889 uschar *log_msg, *smtp_code;
3890 uschar *user_msg = NULL;
3891 uschar *recipient = NULL;
3892 uschar *hello = NULL;
3893 uschar *s, *ss;
3894 BOOL was_rej_mail = FALSE;
3895 BOOL was_rcpt = FALSE;
3896 void (*oldsignal)(int);
3897 pid_t pid;
3898 int start, end, sender_domain, recipient_domain;
3899 int rc;
3900 int c;
3901 auth_instance *au;
3902 uschar *orcpt = NULL;
3903 int flags;
3904 gstring * g;
3905
3906 #ifdef AUTH_TLS
3907 /* Check once per STARTTLS or SSL-on-connect for a TLS AUTH */
3908 if ( tls_in.active.sock >= 0
3909 && tls_in.peercert
3910 && tls_in.certificate_verified
3911 && cmd_list[CMD_LIST_TLS_AUTH].is_mail_cmd
3912 )
3913 {
3914 cmd_list[CMD_LIST_TLS_AUTH].is_mail_cmd = FALSE;
3915
3916 for (au = auths; au; au = au->next)
3917 if (strcmpic(US"tls", au->driver_name) == 0)
3918 {
3919 if ( acl_smtp_auth
3920 && (rc = acl_check(ACL_WHERE_AUTH, NULL, acl_smtp_auth,
3921 &user_msg, &log_msg)) != OK
3922 )
3923 done = smtp_handle_acl_fail(ACL_WHERE_AUTH, rc, user_msg, log_msg);
3924 else
3925 {
3926 smtp_cmd_data = NULL;
3927
3928 if (smtp_in_auth(au, &s, &ss) == OK)
3929 { DEBUG(D_auth) debug_printf("tls auth succeeded\n"); }
3930 else
3931 { DEBUG(D_auth) debug_printf("tls auth not succeeded\n"); }
3932 }
3933 break;
3934 }
3935 }
3936 #endif
3937
3938 #ifdef TCP_QUICKACK
3939 if (smtp_in) /* Avoid pure-ACKs while in cmd pingpong phase */
3940 (void) setsockopt(fileno(smtp_in), IPPROTO_TCP, TCP_QUICKACK,
3941 US &off, sizeof(off));
3942 #endif
3943
3944 switch(smtp_read_command(TRUE, GETC_BUFFER_UNLIMITED))
3945 {
3946 /* The AUTH command is not permitted to occur inside a transaction, and may
3947 occur successfully only once per connection. Actually, that isn't quite
3948 true. When TLS is started, all previous information about a connection must
3949 be discarded, so a new AUTH is permitted at that time.
3950
3951 AUTH may only be used when it has been advertised. However, it seems that
3952 there are clients that send AUTH when it hasn't been advertised, some of
3953 them even doing this after HELO. And there are MTAs that accept this. Sigh.
3954 So there's a get-out that allows this to happen.
3955
3956 AUTH is initially labelled as a "nonmail command" so that one occurrence
3957 doesn't get counted. We change the label here so that multiple failing
3958 AUTHS will eventually hit the nonmail threshold. */
3959
3960 case AUTH_CMD:
3961 HAD(SCH_AUTH);
3962 authentication_failed = TRUE;
3963 cmd_list[CMD_LIST_AUTH].is_mail_cmd = FALSE;
3964
3965 if (!auth_advertised && !f.allow_auth_unadvertised)
3966 {
3967 done = synprot_error(L_smtp_protocol_error, 503, NULL,
3968 US"AUTH command used when not advertised");
3969 break;
3970 }
3971 if (sender_host_authenticated)
3972 {
3973 done = synprot_error(L_smtp_protocol_error, 503, NULL,
3974 US"already authenticated");
3975 break;
3976 }
3977 if (sender_address)
3978 {
3979 done = synprot_error(L_smtp_protocol_error, 503, NULL,
3980 US"not permitted in mail transaction");
3981 break;
3982 }
3983
3984 /* Check the ACL */
3985
3986 if ( acl_smtp_auth
3987 && (rc = acl_check(ACL_WHERE_AUTH, NULL, acl_smtp_auth,
3988 &user_msg, &log_msg)) != OK
3989 )
3990 {
3991 done = smtp_handle_acl_fail(ACL_WHERE_AUTH, rc, user_msg, log_msg);
3992 break;
3993 }
3994
3995 /* Find the name of the requested authentication mechanism. */
3996
3997 s = smtp_cmd_data;
3998 while ((c = *smtp_cmd_data) != 0 && !isspace(c))
3999 {
4000 if (!isalnum(c) && c != '-' && c != '_')
4001 {
4002 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4003 US"invalid character in authentication mechanism name");
4004 goto COMMAND_LOOP;
4005 }
4006 smtp_cmd_data++;
4007 }
4008
4009 /* If not at the end of the line, we must be at white space. Terminate the
4010 name and move the pointer on to any data that may be present. */
4011
4012 if (*smtp_cmd_data != 0)
4013 {
4014 *smtp_cmd_data++ = 0;
4015 while (isspace(*smtp_cmd_data)) smtp_cmd_data++;
4016 }
4017
4018 /* Search for an authentication mechanism which is configured for use
4019 as a server and which has been advertised (unless, sigh, allow_auth_
4020 unadvertised is set). */
4021
4022 for (au = auths; au; au = au->next)
4023 if (strcmpic(s, au->public_name) == 0 && au->server &&
4024 (au->advertised || f.allow_auth_unadvertised))
4025 break;
4026
4027 if (au)
4028 {
4029 c = smtp_in_auth(au, &s, &ss);
4030
4031 smtp_printf("%s\r\n", FALSE, s);
4032 if (c != OK)
4033 log_write(0, LOG_MAIN|LOG_REJECT, "%s authenticator failed for %s: %s",
4034 au->name, host_and_ident(FALSE), ss);
4035 }
4036 else
4037 done = synprot_error(L_smtp_protocol_error, 504, NULL,
4038 string_sprintf("%s authentication mechanism not supported", s));
4039
4040 break; /* AUTH_CMD */
4041
4042 /* The HELO/EHLO commands are permitted to appear in the middle of a
4043 session as well as at the beginning. They have the effect of a reset in
4044 addition to their other functions. Their absence at the start cannot be
4045 taken to be an error.
4046
4047 RFC 2821 says:
4048
4049 If the EHLO command is not acceptable to the SMTP server, 501, 500,
4050 or 502 failure replies MUST be returned as appropriate. The SMTP
4051 server MUST stay in the same state after transmitting these replies
4052 that it was in before the EHLO was received.
4053
4054 Therefore, we do not do the reset until after checking the command for
4055 acceptability. This change was made for Exim release 4.11. Previously
4056 it did the reset first. */
4057
4058 case HELO_CMD:
4059 HAD(SCH_HELO);
4060 hello = US"HELO";
4061 esmtp = FALSE;
4062 goto HELO_EHLO;
4063
4064 case EHLO_CMD:
4065 HAD(SCH_EHLO);
4066 hello = US"EHLO";
4067 esmtp = TRUE;
4068
4069 HELO_EHLO: /* Common code for HELO and EHLO */
4070 cmd_list[CMD_LIST_HELO].is_mail_cmd = FALSE;
4071 cmd_list[CMD_LIST_EHLO].is_mail_cmd = FALSE;
4072
4073 /* Reject the HELO if its argument was invalid or non-existent. A
4074 successful check causes the argument to be saved in malloc store. */
4075
4076 if (!check_helo(smtp_cmd_data))
4077 {
4078 smtp_printf("501 Syntactically invalid %s argument(s)\r\n", FALSE, hello);
4079
4080 log_write(0, LOG_MAIN|LOG_REJECT, "rejected %s from %s: syntactically "
4081 "invalid argument(s): %s", hello, host_and_ident(FALSE),
4082 *smtp_cmd_argument == 0 ? US"(no argument given)" :
4083 string_printing(smtp_cmd_argument));
4084
4085 if (++synprot_error_count > smtp_max_synprot_errors)
4086 {
4087 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
4088 "syntax or protocol errors (last command was \"%s\")",
4089 host_and_ident(FALSE), string_printing(smtp_cmd_buffer));
4090 done = 1;
4091 }
4092
4093 break;
4094 }
4095
4096 /* If sender_host_unknown is true, we have got here via the -bs interface,
4097 not called from inetd. Otherwise, we are running an IP connection and the
4098 host address will be set. If the helo name is the primary name of this
4099 host and we haven't done a reverse lookup, force one now. If helo_required
4100 is set, ensure that the HELO name matches the actual host. If helo_verify
4101 is set, do the same check, but softly. */
4102
4103 if (!f.sender_host_unknown)
4104 {
4105 BOOL old_helo_verified = f.helo_verified;
4106 uschar *p = smtp_cmd_data;
4107
4108 while (*p != 0 && !isspace(*p)) { *p = tolower(*p); p++; }
4109 *p = 0;
4110
4111 /* Force a reverse lookup if HELO quoted something in helo_lookup_domains
4112 because otherwise the log can be confusing. */
4113
4114 if ( !sender_host_name
4115 && (deliver_domain = sender_helo_name, /* set $domain */
4116 match_isinlist(sender_helo_name, CUSS &helo_lookup_domains, 0,