40fd3083b550cc137e519df140078eb322bace00
[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 struct {
135 BOOL auth_advertised :1;
136 #ifdef SUPPORT_TLS
137 BOOL tls_advertised :1;
138 #endif
139 BOOL dsn_advertised :1;
140 BOOL esmtp :1;
141 BOOL helo_required :1;
142 BOOL helo_verify :1;
143 BOOL helo_seen :1;
144 BOOL helo_accept_junk :1;
145 #ifdef EXPERIMENTAL_PIPE_CONNECT
146 BOOL pipe_connect_acceptable :1;
147 #endif
148 BOOL rcpt_smtp_response_same :1;
149 BOOL rcpt_in_progress :1;
150 BOOL smtp_exit_function_called :1;
151 #ifdef SUPPORT_I18N
152 BOOL smtputf8_advertised :1;
153 #endif
154 } fl = {
155 .helo_required = FALSE,
156 .helo_verify = FALSE,
157 .smtp_exit_function_called = FALSE,
158 };
159
160 static auth_instance *authenticated_by;
161 static int count_nonmail;
162 static int nonmail_command_count;
163 static int synprot_error_count;
164 static int unknown_command_count;
165 static int sync_cmd_limit;
166 static int smtp_write_error = 0;
167
168 static uschar *rcpt_smtp_response;
169 static uschar *smtp_data_buffer;
170 static uschar *smtp_cmd_data;
171
172 /* We need to know the position of RSET, HELO, EHLO, AUTH, and STARTTLS. Their
173 final fields of all except AUTH are forced TRUE at the start of a new message
174 setup, to allow one of each between messages that is not counted as a nonmail
175 command. (In fact, only one of HELO/EHLO is not counted.) Also, we have to
176 allow a new EHLO after starting up TLS.
177
178 AUTH is "falsely" labelled as a mail command initially, so that it doesn't get
179 counted. However, the flag is changed when AUTH is received, so that multiple
180 failing AUTHs will eventually hit the limit. After a successful AUTH, another
181 AUTH is already forbidden. After a TLS session is started, AUTH's flag is again
182 forced TRUE, to allow for the re-authentication that can happen at that point.
183
184 QUIT is also "falsely" labelled as a mail command so that it doesn't up the
185 count of non-mail commands and possibly provoke an error.
186
187 tls_auth is a pseudo-command, never expected in input. It is activated
188 on TLS startup and looks for a tls authenticator. */
189
190 static smtp_cmd_list cmd_list[] = {
191 /* name len cmd has_arg is_mail_cmd */
192
193 { "rset", sizeof("rset")-1, RSET_CMD, FALSE, FALSE }, /* First */
194 { "helo", sizeof("helo")-1, HELO_CMD, TRUE, FALSE },
195 { "ehlo", sizeof("ehlo")-1, EHLO_CMD, TRUE, FALSE },
196 { "auth", sizeof("auth")-1, AUTH_CMD, TRUE, TRUE },
197 #ifdef SUPPORT_TLS
198 { "starttls", sizeof("starttls")-1, STARTTLS_CMD, FALSE, FALSE },
199 { "tls_auth", 0, TLS_AUTH_CMD, FALSE, FALSE },
200 #endif
201
202 /* If you change anything above here, also fix the definitions below. */
203
204 { "mail from:", sizeof("mail from:")-1, MAIL_CMD, TRUE, TRUE },
205 { "rcpt to:", sizeof("rcpt to:")-1, RCPT_CMD, TRUE, TRUE },
206 { "data", sizeof("data")-1, DATA_CMD, FALSE, TRUE },
207 { "bdat", sizeof("bdat")-1, BDAT_CMD, TRUE, TRUE },
208 { "quit", sizeof("quit")-1, QUIT_CMD, FALSE, TRUE },
209 { "noop", sizeof("noop")-1, NOOP_CMD, TRUE, FALSE },
210 { "etrn", sizeof("etrn")-1, ETRN_CMD, TRUE, FALSE },
211 { "vrfy", sizeof("vrfy")-1, VRFY_CMD, TRUE, FALSE },
212 { "expn", sizeof("expn")-1, EXPN_CMD, TRUE, FALSE },
213 { "help", sizeof("help")-1, HELP_CMD, TRUE, FALSE }
214 };
215
216 static smtp_cmd_list *cmd_list_end =
217 cmd_list + sizeof(cmd_list)/sizeof(smtp_cmd_list);
218
219 #define CMD_LIST_RSET 0
220 #define CMD_LIST_HELO 1
221 #define CMD_LIST_EHLO 2
222 #define CMD_LIST_AUTH 3
223 #define CMD_LIST_STARTTLS 4
224 #define CMD_LIST_TLS_AUTH 5
225
226 /* This list of names is used for performing the smtp_no_mail logging action.
227 It must be kept in step with the SCH_xxx enumerations. */
228
229 static uschar *smtp_names[] =
230 {
231 US"NONE", US"AUTH", US"DATA", US"BDAT", US"EHLO", US"ETRN", US"EXPN",
232 US"HELO", US"HELP", US"MAIL", US"NOOP", US"QUIT", US"RCPT", US"RSET",
233 US"STARTTLS", US"VRFY" };
234
235 static uschar *protocols_local[] = {
236 US"local-smtp", /* HELO */
237 US"local-smtps", /* The rare case EHLO->STARTTLS->HELO */
238 US"local-esmtp", /* EHLO */
239 US"local-esmtps", /* EHLO->STARTTLS->EHLO */
240 US"local-esmtpa", /* EHLO->AUTH */
241 US"local-esmtpsa" /* EHLO->STARTTLS->EHLO->AUTH */
242 };
243 static uschar *protocols[] = {
244 US"smtp", /* HELO */
245 US"smtps", /* The rare case EHLO->STARTTLS->HELO */
246 US"esmtp", /* EHLO */
247 US"esmtps", /* EHLO->STARTTLS->EHLO */
248 US"esmtpa", /* EHLO->AUTH */
249 US"esmtpsa" /* EHLO->STARTTLS->EHLO->AUTH */
250 };
251
252 #define pnormal 0
253 #define pextend 2
254 #define pcrpted 1 /* added to pextend or pnormal */
255 #define pauthed 2 /* added to pextend */
256
257 /* Sanity check and validate optional args to MAIL FROM: envelope */
258 enum {
259 ENV_MAIL_OPT_NULL,
260 ENV_MAIL_OPT_SIZE, ENV_MAIL_OPT_BODY, ENV_MAIL_OPT_AUTH,
261 #ifndef DISABLE_PRDR
262 ENV_MAIL_OPT_PRDR,
263 #endif
264 ENV_MAIL_OPT_RET, ENV_MAIL_OPT_ENVID,
265 #ifdef SUPPORT_I18N
266 ENV_MAIL_OPT_UTF8,
267 #endif
268 };
269 typedef struct {
270 uschar * name; /* option requested during MAIL cmd */
271 int value; /* enum type */
272 BOOL need_value; /* TRUE requires value (name=value pair format)
273 FALSE is a singleton */
274 } env_mail_type_t;
275 static env_mail_type_t env_mail_type_list[] = {
276 { US"SIZE", ENV_MAIL_OPT_SIZE, TRUE },
277 { US"BODY", ENV_MAIL_OPT_BODY, TRUE },
278 { US"AUTH", ENV_MAIL_OPT_AUTH, TRUE },
279 #ifndef DISABLE_PRDR
280 { US"PRDR", ENV_MAIL_OPT_PRDR, FALSE },
281 #endif
282 { US"RET", ENV_MAIL_OPT_RET, TRUE },
283 { US"ENVID", ENV_MAIL_OPT_ENVID, TRUE },
284 #ifdef SUPPORT_I18N
285 { US"SMTPUTF8",ENV_MAIL_OPT_UTF8, FALSE }, /* rfc6531 */
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 #ifdef EXPERIMENTAL_PIPE_CONNECT
401 static BOOL
402 pipeline_connect_sends(void)
403 {
404 if (!sender_host_address || f.sender_host_notsocket || !fl.pipe_connect_acceptable)
405 return FALSE;
406
407 if (wouldblock_reading()) return FALSE;
408 f.smtp_in_early_pipe_used = TRUE;
409 return TRUE;
410 }
411 #endif
412
413 /*************************************************
414 * Log incomplete transactions *
415 *************************************************/
416
417 /* This function is called after a transaction has been aborted by RSET, QUIT,
418 connection drops or other errors. It logs the envelope information received
419 so far in order to preserve address verification attempts.
420
421 Argument: string to indicate what aborted the transaction
422 Returns: nothing
423 */
424
425 static void
426 incomplete_transaction_log(uschar *what)
427 {
428 if (!sender_address /* No transaction in progress */
429 || !LOGGING(smtp_incomplete_transaction))
430 return;
431
432 /* Build list of recipients for logging */
433
434 if (recipients_count > 0)
435 {
436 raw_recipients = store_get(recipients_count * sizeof(uschar *));
437 for (int i = 0; i < recipients_count; i++)
438 raw_recipients[i] = recipients_list[i].address;
439 raw_recipients_count = recipients_count;
440 }
441
442 log_write(L_smtp_incomplete_transaction, LOG_MAIN|LOG_SENDER|LOG_RECIPIENTS,
443 "%s incomplete transaction (%s)", host_and_ident(TRUE), what);
444 }
445
446
447
448
449 void
450 smtp_command_timeout_exit(void)
451 {
452 log_write(L_lost_incoming_connection,
453 LOG_MAIN, "SMTP command timeout on%s connection from %s",
454 tls_in.active.sock >= 0 ? " TLS" : "", host_and_ident(FALSE));
455 if (smtp_batched_input)
456 moan_smtp_batch(NULL, "421 SMTP command timeout"); /* Does not return */
457 smtp_notquit_exit(US"command-timeout", US"421",
458 US"%s: SMTP command timeout - closing connection",
459 smtp_active_hostname);
460 exim_exit(EXIT_FAILURE, US"receiving");
461 }
462
463 void
464 smtp_command_sigterm_exit(void)
465 {
466 log_write(0, LOG_MAIN, "%s closed after SIGTERM", smtp_get_connection_info());
467 if (smtp_batched_input)
468 moan_smtp_batch(NULL, "421 SIGTERM received"); /* Does not return */
469 smtp_notquit_exit(US"signal-exit", US"421",
470 US"%s: Service not available - closing connection", smtp_active_hostname);
471 exim_exit(EXIT_FAILURE, US"receiving");
472 }
473
474 void
475 smtp_data_timeout_exit(void)
476 {
477 log_write(L_lost_incoming_connection,
478 LOG_MAIN, "SMTP data timeout (message abandoned) on connection from %s F=<%s>",
479 sender_fullhost ? sender_fullhost : US"local process", sender_address);
480 receive_bomb_out(US"data-timeout", US"SMTP incoming data timeout");
481 /* Does not return */
482 }
483
484 void
485 smtp_data_sigint_exit(void)
486 {
487 log_write(0, LOG_MAIN, "%s closed after %s",
488 smtp_get_connection_info(), had_data_sigint == SIGTERM ? "SIGTERM":"SIGINT");
489 receive_bomb_out(US"signal-exit",
490 US"Service not available - SIGTERM or SIGINT received");
491 /* Does not return */
492 }
493
494
495
496 /* Refill the buffer, and notify DKIM verification code.
497 Return false for error or EOF.
498 */
499
500 static BOOL
501 smtp_refill(unsigned lim)
502 {
503 int rc, save_errno;
504 if (!smtp_out) return FALSE;
505 fflush(smtp_out);
506 if (smtp_receive_timeout > 0) ALARM(smtp_receive_timeout);
507
508 /* Limit amount read, so non-message data is not fed to DKIM.
509 Take care to not touch the safety NUL at the end of the buffer. */
510
511 rc = read(fileno(smtp_in), smtp_inbuffer, MIN(IN_BUFFER_SIZE-1, lim));
512 save_errno = errno;
513 if (smtp_receive_timeout > 0) ALARM_CLR(0);
514 if (rc <= 0)
515 {
516 /* Must put the error text in fixed store, because this might be during
517 header reading, where it releases unused store above the header. */
518 if (rc < 0)
519 {
520 if (had_command_timeout) /* set by signal handler */
521 smtp_command_timeout_exit(); /* does not return */
522 if (had_command_sigterm)
523 smtp_command_sigterm_exit();
524 if (had_data_timeout)
525 smtp_data_timeout_exit();
526 if (had_data_sigint)
527 smtp_data_sigint_exit();
528
529 smtp_had_error = save_errno;
530 smtp_read_error = string_copy_malloc(
531 string_sprintf(" (error: %s)", strerror(save_errno)));
532 }
533 else
534 smtp_had_eof = 1;
535 return FALSE;
536 }
537 #ifndef DISABLE_DKIM
538 dkim_exim_verify_feed(smtp_inbuffer, rc);
539 #endif
540 smtp_inend = smtp_inbuffer + rc;
541 smtp_inptr = smtp_inbuffer;
542 return TRUE;
543 }
544
545 /*************************************************
546 * SMTP version of getc() *
547 *************************************************/
548
549 /* This gets the next byte from the SMTP input buffer. If the buffer is empty,
550 it flushes the output, and refills the buffer, with a timeout. The signal
551 handler is set appropriately by the calling function. This function is not used
552 after a connection has negotiated itself into an TLS/SSL state.
553
554 Arguments: lim Maximum amount to read/buffer
555 Returns: the next character or EOF
556 */
557
558 int
559 smtp_getc(unsigned lim)
560 {
561 if (smtp_inptr >= smtp_inend)
562 if (!smtp_refill(lim))
563 return EOF;
564 return *smtp_inptr++;
565 }
566
567 uschar *
568 smtp_getbuf(unsigned * len)
569 {
570 unsigned size;
571 uschar * buf;
572
573 if (smtp_inptr >= smtp_inend)
574 if (!smtp_refill(*len))
575 { *len = 0; return NULL; }
576
577 if ((size = smtp_inend - smtp_inptr) > *len) size = *len;
578 buf = smtp_inptr;
579 smtp_inptr += size;
580 *len = size;
581 return buf;
582 }
583
584 void
585 smtp_get_cache(void)
586 {
587 #ifndef DISABLE_DKIM
588 int n = smtp_inend - smtp_inptr;
589 if (n > 0)
590 dkim_exim_verify_feed(smtp_inptr, n);
591 #endif
592 }
593
594
595 /* Get a byte from the smtp input, in CHUNKING mode. Handle ack of the
596 previous BDAT chunk and getting new ones when we run out. Uses the
597 underlying smtp_getc or tls_getc both for that and for getting the
598 (buffered) data byte. EOD signals (an expected) no further data.
599 ERR signals a protocol error, and EOF a closed input stream.
600
601 Called from read_bdat_smtp() in receive.c for the message body, but also
602 by the headers read loop in receive_msg(); manipulates chunking_state
603 to handle the BDAT command/response.
604 Placed here due to the correlation with the above smtp_getc(), which it wraps,
605 and also by the need to do smtp command/response handling.
606
607 Arguments: lim (ignored)
608 Returns: the next character or ERR, EOD or EOF
609 */
610
611 int
612 bdat_getc(unsigned lim)
613 {
614 uschar * user_msg = NULL;
615 uschar * log_msg;
616
617 for(;;)
618 {
619 #ifndef DISABLE_DKIM
620 unsigned dkim_save;
621 #endif
622
623 if (chunking_data_left > 0)
624 return lwr_receive_getc(chunking_data_left--);
625
626 receive_getc = lwr_receive_getc;
627 receive_getbuf = lwr_receive_getbuf;
628 receive_ungetc = lwr_receive_ungetc;
629 #ifndef DISABLE_DKIM
630 dkim_save = dkim_collect_input;
631 dkim_collect_input = 0;
632 #endif
633
634 /* Unless PIPELINING was offered, there should be no next command
635 until after we ack that chunk */
636
637 if (!f.smtp_in_pipelining_advertised && !check_sync())
638 {
639 unsigned n = smtp_inend - smtp_inptr;
640 if (n > 32) n = 32;
641
642 incomplete_transaction_log(US"sync failure");
643 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP protocol synchronization error "
644 "(next input sent too soon: pipelining was not advertised): "
645 "rejected \"%s\" %s next input=\"%s\"%s",
646 smtp_cmd_buffer, host_and_ident(TRUE),
647 string_printing(string_copyn(smtp_inptr, n)),
648 smtp_inend - smtp_inptr > n ? "..." : "");
649 (void) synprot_error(L_smtp_protocol_error, 554, NULL,
650 US"SMTP synchronization error");
651 goto repeat_until_rset;
652 }
653
654 /* If not the last, ack the received chunk. The last response is delayed
655 until after the data ACL decides on it */
656
657 if (chunking_state == CHUNKING_LAST)
658 {
659 #ifndef DISABLE_DKIM
660 dkim_exim_verify_feed(NULL, 0); /* notify EOD */
661 #endif
662 return EOD;
663 }
664
665 smtp_printf("250 %u byte chunk received\r\n", FALSE, chunking_datasize);
666 chunking_state = CHUNKING_OFFERED;
667 DEBUG(D_receive) debug_printf("chunking state %d\n", (int)chunking_state);
668
669 /* Expect another BDAT cmd from input. RFC 3030 says nothing about
670 QUIT, RSET or NOOP but handling them seems obvious */
671
672 next_cmd:
673 switch(smtp_read_command(TRUE, 1))
674 {
675 default:
676 (void) synprot_error(L_smtp_protocol_error, 503, NULL,
677 US"only BDAT permissible after non-LAST BDAT");
678
679 repeat_until_rset:
680 switch(smtp_read_command(TRUE, 1))
681 {
682 case QUIT_CMD: smtp_quit_handler(&user_msg, &log_msg); /*FALLTHROUGH */
683 case EOF_CMD: return EOF;
684 case RSET_CMD: smtp_rset_handler(); return ERR;
685 default: if (synprot_error(L_smtp_protocol_error, 503, NULL,
686 US"only RSET accepted now") > 0)
687 return EOF;
688 goto repeat_until_rset;
689 }
690
691 case QUIT_CMD:
692 smtp_quit_handler(&user_msg, &log_msg);
693 /*FALLTHROUGH*/
694 case EOF_CMD:
695 return EOF;
696
697 case RSET_CMD:
698 smtp_rset_handler();
699 return ERR;
700
701 case NOOP_CMD:
702 HAD(SCH_NOOP);
703 smtp_printf("250 OK\r\n", FALSE);
704 goto next_cmd;
705
706 case BDAT_CMD:
707 {
708 int n;
709
710 if (sscanf(CS smtp_cmd_data, "%u %n", &chunking_datasize, &n) < 1)
711 {
712 (void) synprot_error(L_smtp_protocol_error, 501, NULL,
713 US"missing size for BDAT command");
714 return ERR;
715 }
716 chunking_state = strcmpic(smtp_cmd_data+n, US"LAST") == 0
717 ? CHUNKING_LAST : CHUNKING_ACTIVE;
718 chunking_data_left = chunking_datasize;
719 DEBUG(D_receive) debug_printf("chunking state %d, %d bytes\n",
720 (int)chunking_state, chunking_data_left);
721
722 if (chunking_datasize == 0)
723 if (chunking_state == CHUNKING_LAST)
724 return EOD;
725 else
726 {
727 (void) synprot_error(L_smtp_protocol_error, 504, NULL,
728 US"zero size for BDAT command");
729 goto repeat_until_rset;
730 }
731
732 receive_getc = bdat_getc;
733 receive_getbuf = bdat_getbuf; /* r~getbuf is never actually used */
734 receive_ungetc = bdat_ungetc;
735 #ifndef DISABLE_DKIM
736 dkim_collect_input = dkim_save;
737 #endif
738 break; /* to top of main loop */
739 }
740 }
741 }
742 }
743
744 uschar *
745 bdat_getbuf(unsigned * len)
746 {
747 uschar * buf;
748
749 if (chunking_data_left <= 0)
750 { *len = 0; return NULL; }
751
752 if (*len > chunking_data_left) *len = chunking_data_left;
753 buf = lwr_receive_getbuf(len); /* Either smtp_getbuf or tls_getbuf */
754 chunking_data_left -= *len;
755 return buf;
756 }
757
758 void
759 bdat_flush_data(void)
760 {
761 while (chunking_data_left)
762 {
763 unsigned n = chunking_data_left;
764 if (!bdat_getbuf(&n)) break;
765 }
766
767 receive_getc = lwr_receive_getc;
768 receive_getbuf = lwr_receive_getbuf;
769 receive_ungetc = lwr_receive_ungetc;
770
771 if (chunking_state != CHUNKING_LAST)
772 {
773 chunking_state = CHUNKING_OFFERED;
774 DEBUG(D_receive) debug_printf("chunking state %d\n", (int)chunking_state);
775 }
776 }
777
778
779
780
781 /*************************************************
782 * SMTP version of ungetc() *
783 *************************************************/
784
785 /* Puts a character back in the input buffer. Only ever
786 called once.
787
788 Arguments:
789 ch the character
790
791 Returns: the character
792 */
793
794 int
795 smtp_ungetc(int ch)
796 {
797 *--smtp_inptr = ch;
798 return ch;
799 }
800
801
802 int
803 bdat_ungetc(int ch)
804 {
805 chunking_data_left++;
806 return lwr_receive_ungetc(ch);
807 }
808
809
810
811 /*************************************************
812 * SMTP version of feof() *
813 *************************************************/
814
815 /* Tests for a previous EOF
816
817 Arguments: none
818 Returns: non-zero if the eof flag is set
819 */
820
821 int
822 smtp_feof(void)
823 {
824 return smtp_had_eof;
825 }
826
827
828
829
830 /*************************************************
831 * SMTP version of ferror() *
832 *************************************************/
833
834 /* Tests for a previous read error, and returns with errno
835 restored to what it was when the error was detected.
836
837 Arguments: none
838 Returns: non-zero if the error flag is set
839 */
840
841 int
842 smtp_ferror(void)
843 {
844 errno = smtp_had_error;
845 return smtp_had_error;
846 }
847
848
849
850 /*************************************************
851 * Test for characters in the SMTP buffer *
852 *************************************************/
853
854 /* Used at the end of a message
855
856 Arguments: none
857 Returns: TRUE/FALSE
858 */
859
860 BOOL
861 smtp_buffered(void)
862 {
863 return smtp_inptr < smtp_inend;
864 }
865
866
867
868 /*************************************************
869 * Write formatted string to SMTP channel *
870 *************************************************/
871
872 /* This is a separate function so that we don't have to repeat everything for
873 TLS support or debugging. It is global so that the daemon and the
874 authentication functions can use it. It does not return any error indication,
875 because major problems such as dropped connections won't show up till an output
876 flush for non-TLS connections. The smtp_fflush() function is available for
877 checking that: for convenience, TLS output errors are remembered here so that
878 they are also picked up later by smtp_fflush().
879
880 Arguments:
881 format format string
882 more further data expected
883 ... optional arguments
884
885 Returns: nothing
886 */
887
888 void
889 smtp_printf(const char *format, BOOL more, ...)
890 {
891 va_list ap;
892
893 va_start(ap, more);
894 smtp_vprintf(format, more, ap);
895 va_end(ap);
896 }
897
898 /* This is split off so that verify.c:respond_printf() can, in effect, call
899 smtp_printf(), bearing in mind that in C a vararg function can't directly
900 call another vararg function, only a function which accepts a va_list. */
901
902 void
903 smtp_vprintf(const char *format, BOOL more, va_list ap)
904 {
905 gstring gs = { .size = big_buffer_size, .ptr = 0, .s = big_buffer };
906 BOOL yield;
907
908 yield = !! string_vformat(&gs, FALSE, format, ap);
909 string_from_gstring(&gs);
910
911 DEBUG(D_receive)
912 {
913 void *reset_point = store_get(0);
914 uschar *msg_copy, *cr, *end;
915 msg_copy = string_copy(gs.s);
916 end = msg_copy + gs.ptr;
917 while ((cr = Ustrchr(msg_copy, '\r')) != NULL) /* lose CRs */
918 memmove(cr, cr + 1, (end--) - cr);
919 debug_printf("SMTP>> %s", msg_copy);
920 store_reset(reset_point);
921 }
922
923 if (!yield)
924 {
925 log_write(0, LOG_MAIN|LOG_PANIC, "string too large in smtp_printf()");
926 smtp_closedown(US"Unexpected error");
927 exim_exit(EXIT_FAILURE, NULL);
928 }
929
930 /* If this is the first output for a (non-batch) RCPT command, see if all RCPTs
931 have had the same. Note: this code is also present in smtp_respond(). It would
932 be tidier to have it only in one place, but when it was added, it was easier to
933 do it that way, so as not to have to mess with the code for the RCPT command,
934 which sometimes uses smtp_printf() and sometimes smtp_respond(). */
935
936 if (fl.rcpt_in_progress)
937 {
938 if (rcpt_smtp_response == NULL)
939 rcpt_smtp_response = string_copy(big_buffer);
940 else if (fl.rcpt_smtp_response_same &&
941 Ustrcmp(rcpt_smtp_response, big_buffer) != 0)
942 fl.rcpt_smtp_response_same = FALSE;
943 fl.rcpt_in_progress = FALSE;
944 }
945
946 /* Now write the string */
947
948 #ifdef SUPPORT_TLS
949 if (tls_in.active.sock >= 0)
950 {
951 if (tls_write(NULL, gs.s, gs.ptr, more) < 0)
952 smtp_write_error = -1;
953 }
954 else
955 #endif
956
957 if (fprintf(smtp_out, "%s", gs.s) < 0) smtp_write_error = -1;
958 }
959
960
961
962 /*************************************************
963 * Flush SMTP out and check for error *
964 *************************************************/
965
966 /* This function isn't currently used within Exim (it detects errors when it
967 tries to read the next SMTP input), but is available for use in local_scan().
968 For non-TLS connections, it flushes the output and checks for errors. For
969 TLS-connections, it checks for a previously-detected TLS write error.
970
971 Arguments: none
972 Returns: 0 for no error; -1 after an error
973 */
974
975 int
976 smtp_fflush(void)
977 {
978 if (tls_in.active.sock < 0 && fflush(smtp_out) != 0) smtp_write_error = -1;
979 return smtp_write_error;
980 }
981
982
983
984 /*************************************************
985 * SMTP command read timeout *
986 *************************************************/
987
988 /* Signal handler for timing out incoming SMTP commands. This attempts to
989 finish off tidily.
990
991 Argument: signal number (SIGALRM)
992 Returns: nothing
993 */
994
995 static void
996 command_timeout_handler(int sig)
997 {
998 had_command_timeout = sig;
999 }
1000
1001
1002
1003 /*************************************************
1004 * SIGTERM received *
1005 *************************************************/
1006
1007 /* Signal handler for handling SIGTERM. Again, try to finish tidily.
1008
1009 Argument: signal number (SIGTERM)
1010 Returns: nothing
1011 */
1012
1013 static void
1014 command_sigterm_handler(int sig)
1015 {
1016 had_command_sigterm = sig;
1017 }
1018
1019
1020
1021
1022 #ifdef SUPPORT_PROXY
1023 /*************************************************
1024 * Restore socket timeout to previous value *
1025 *************************************************/
1026 /* If the previous value was successfully retrieved, restore
1027 it before returning control to the non-proxy routines
1028
1029 Arguments: fd - File descriptor for input
1030 get_ok - Successfully retrieved previous values
1031 tvtmp - Time struct with previous values
1032 vslen - Length of time struct
1033 Returns: none
1034 */
1035 static void
1036 restore_socket_timeout(int fd, int get_ok, struct timeval * tvtmp, socklen_t vslen)
1037 {
1038 if (get_ok == 0)
1039 (void) setsockopt(fd, SOL_SOCKET, SO_RCVTIMEO, CS tvtmp, vslen);
1040 }
1041
1042 /*************************************************
1043 * Check if host is required proxy host *
1044 *************************************************/
1045 /* The function determines if inbound host will be a regular smtp host
1046 or if it is configured that it must use Proxy Protocol. A local
1047 connection cannot.
1048
1049 Arguments: none
1050 Returns: bool
1051 */
1052
1053 static BOOL
1054 check_proxy_protocol_host()
1055 {
1056 int rc;
1057
1058 if ( sender_host_address
1059 && (rc = verify_check_this_host(CUSS &hosts_proxy, NULL, NULL,
1060 sender_host_address, NULL)) == OK)
1061 {
1062 DEBUG(D_receive)
1063 debug_printf("Detected proxy protocol configured host\n");
1064 proxy_session = TRUE;
1065 }
1066 return proxy_session;
1067 }
1068
1069
1070 /*************************************************
1071 * Read data until newline or end of buffer *
1072 *************************************************/
1073 /* While SMTP is server-speaks-first, TLS is client-speaks-first, so we can't
1074 read an entire buffer and assume there will be nothing past a proxy protocol
1075 header. Our approach normally is to use stdio, but again that relies upon
1076 "STARTTLS\r\n" and a server response before the client starts TLS handshake, or
1077 reading _nothing_ before client TLS handshake. So we don't want to use the
1078 usual buffering reads which may read enough to block TLS starting.
1079
1080 So unfortunately we're down to "read one byte at a time, with a syscall each,
1081 and expect a little overhead", for all proxy-opened connections which are v1,
1082 just to handle the TLS-on-connect case. Since SSL functions wrap the
1083 underlying fd, we can't assume that we can feed them any already-read content.
1084
1085 We need to know where to read to, the max capacity, and we'll read until we
1086 get a CR and one more character. Let the caller scream if it's CR+!LF.
1087
1088 Return the amount read.
1089 */
1090
1091 static int
1092 swallow_until_crlf(int fd, uschar *base, int already, int capacity)
1093 {
1094 uschar *to = base + already;
1095 uschar *cr;
1096 int have = 0;
1097 int ret;
1098 int last = 0;
1099
1100 /* For "PROXY UNKNOWN\r\n" we, at time of writing, expect to have read
1101 up through the \r; for the _normal_ case, we haven't yet seen the \r. */
1102
1103 cr = memchr(base, '\r', already);
1104 if (cr != NULL)
1105 {
1106 if ((cr - base) < already - 1)
1107 {
1108 /* \r and presumed \n already within what we have; probably not
1109 actually proxy protocol, but abort cleanly. */
1110 return 0;
1111 }
1112 /* \r is last character read, just need one more. */
1113 last = 1;
1114 }
1115
1116 while (capacity > 0)
1117 {
1118 do { ret = recv(fd, to, 1, 0); } while (ret == -1 && errno == EINTR);
1119 if (ret == -1)
1120 return -1;
1121 have++;
1122 if (last)
1123 return have;
1124 if (*to == '\r')
1125 last = 1;
1126 capacity--;
1127 to++;
1128 }
1129
1130 /* reached end without having room for a final newline, abort */
1131 errno = EOVERFLOW;
1132 return -1;
1133 }
1134
1135 /*************************************************
1136 * Setup host for proxy protocol *
1137 *************************************************/
1138 /* The function configures the connection based on a header from the
1139 inbound host to use Proxy Protocol. The specification is very exact
1140 so exit with an error if do not find the exact required pieces. This
1141 includes an incorrect number of spaces separating args.
1142
1143 Arguments: none
1144 Returns: Boolean success
1145 */
1146
1147 static void
1148 setup_proxy_protocol_host()
1149 {
1150 union {
1151 struct {
1152 uschar line[108];
1153 } v1;
1154 struct {
1155 uschar sig[12];
1156 uint8_t ver_cmd;
1157 uint8_t fam;
1158 uint16_t len;
1159 union {
1160 struct { /* TCP/UDP over IPv4, len = 12 */
1161 uint32_t src_addr;
1162 uint32_t dst_addr;
1163 uint16_t src_port;
1164 uint16_t dst_port;
1165 } ip4;
1166 struct { /* TCP/UDP over IPv6, len = 36 */
1167 uint8_t src_addr[16];
1168 uint8_t dst_addr[16];
1169 uint16_t src_port;
1170 uint16_t dst_port;
1171 } ip6;
1172 struct { /* AF_UNIX sockets, len = 216 */
1173 uschar src_addr[108];
1174 uschar dst_addr[108];
1175 } unx;
1176 } addr;
1177 } v2;
1178 } hdr;
1179
1180 /* Temp variables used in PPv2 address:port parsing */
1181 uint16_t tmpport;
1182 char tmpip[INET_ADDRSTRLEN];
1183 struct sockaddr_in tmpaddr;
1184 char tmpip6[INET6_ADDRSTRLEN];
1185 struct sockaddr_in6 tmpaddr6;
1186
1187 /* We can't read "all data until end" because while SMTP is
1188 server-speaks-first, the TLS handshake is client-speaks-first, so for
1189 TLS-on-connect ports the proxy protocol header will usually be immediately
1190 followed by a TLS handshake, and with N TLS libraries, we can't reliably
1191 reinject data for reading by those. So instead we first read "enough to be
1192 safely read within the header, and figure out how much more to read".
1193 For v1 we will later read to the end-of-line, for v2 we will read based upon
1194 the stated length.
1195
1196 The v2 sig is 12 octets, and another 4 gets us the length, so we know how much
1197 data is needed total. For v1, where the line looks like:
1198 PROXY TCPn L3src L3dest SrcPort DestPort \r\n
1199
1200 However, for v1 there's also `PROXY UNKNOWN\r\n` which is only 15 octets.
1201 We seem to support that. So, if we read 14 octets then we can tell if we're
1202 v2 or v1. If we're v1, we can continue reading as normal.
1203
1204 If we're v2, we can't slurp up the entire header. We need the length in the
1205 15th & 16th octets, then to read everything after that.
1206
1207 So to safely handle v1 and v2, with client-sent-first supported correctly,
1208 we have to do a minimum of 3 read calls, not 1. Eww.
1209 */
1210
1211 #define PROXY_INITIAL_READ 14
1212 #define PROXY_V2_HEADER_SIZE 16
1213 #if PROXY_INITIAL_READ > PROXY_V2_HEADER_SIZE
1214 # error Code bug in sizes of data to read for proxy usage
1215 #endif
1216
1217 int get_ok = 0;
1218 int size, ret;
1219 int fd = fileno(smtp_in);
1220 const char v2sig[12] = "\x0D\x0A\x0D\x0A\x00\x0D\x0A\x51\x55\x49\x54\x0A";
1221 uschar * iptype; /* To display debug info */
1222 struct timeval tv;
1223 struct timeval tvtmp;
1224 socklen_t vslen = sizeof(struct timeval);
1225 BOOL yield = FALSE;
1226
1227 /* Save current socket timeout values */
1228 get_ok = getsockopt(fd, SOL_SOCKET, SO_RCVTIMEO, CS &tvtmp, &vslen);
1229
1230 /* Proxy Protocol host must send header within a short time
1231 (default 3 seconds) or it's considered invalid */
1232 tv.tv_sec = PROXY_NEGOTIATION_TIMEOUT_SEC;
1233 tv.tv_usec = PROXY_NEGOTIATION_TIMEOUT_USEC;
1234 if (setsockopt(fd, SOL_SOCKET, SO_RCVTIMEO, CS &tv, sizeof(tv)) < 0)
1235 goto bad;
1236
1237 do
1238 {
1239 /* The inbound host was declared to be a Proxy Protocol host, so
1240 don't do a PEEK into the data, actually slurp up enough to be
1241 "safe". Can't take it all because TLS-on-connect clients follow
1242 immediately with TLS handshake. */
1243 ret = recv(fd, &hdr, PROXY_INITIAL_READ, 0);
1244 }
1245 while (ret == -1 && errno == EINTR);
1246
1247 if (ret == -1)
1248 goto proxyfail;
1249
1250 /* For v2, handle reading the length, and then the rest. */
1251 if ((ret == PROXY_INITIAL_READ) && (memcmp(&hdr.v2, v2sig, sizeof(v2sig)) == 0))
1252 {
1253 int retmore;
1254 uint8_t ver;
1255
1256 /* First get the length fields. */
1257 do
1258 {
1259 retmore = recv(fd, (uschar*)&hdr + ret, PROXY_V2_HEADER_SIZE - PROXY_INITIAL_READ, 0);
1260 } while (retmore == -1 && errno == EINTR);
1261 if (retmore == -1)
1262 goto proxyfail;
1263 ret += retmore;
1264
1265 ver = (hdr.v2.ver_cmd & 0xf0) >> 4;
1266
1267 /* May 2014: haproxy combined the version and command into one byte to
1268 allow two full bytes for the length field in order to proxy SSL
1269 connections. SSL Proxy is not supported in this version of Exim, but
1270 must still separate values here. */
1271
1272 if (ver != 0x02)
1273 {
1274 DEBUG(D_receive) debug_printf("Invalid Proxy Protocol version: %d\n", ver);
1275 goto proxyfail;
1276 }
1277
1278 /* The v2 header will always be 16 bytes per the spec. */
1279 size = 16 + ntohs(hdr.v2.len);
1280 DEBUG(D_receive) debug_printf("Detected PROXYv2 header, size %d (limit %d)\n",
1281 size, (int)sizeof(hdr));
1282
1283 /* We should now have 16 octets (PROXY_V2_HEADER_SIZE), and we know the total
1284 amount that we need. Double-check that the size is not unreasonable, then
1285 get the rest. */
1286 if (size > sizeof(hdr))
1287 {
1288 DEBUG(D_receive) debug_printf("PROXYv2 header size unreasonably large; security attack?\n");
1289 goto proxyfail;
1290 }
1291
1292 do
1293 {
1294 do
1295 {
1296 retmore = recv(fd, (uschar*)&hdr + ret, size-ret, 0);
1297 } while (retmore == -1 && errno == EINTR);
1298 if (retmore == -1)
1299 goto proxyfail;
1300 ret += retmore;
1301 DEBUG(D_receive) debug_printf("PROXYv2: have %d/%d required octets\n", ret, size);
1302 } while (ret < size);
1303
1304 } /* end scope for getting rest of data for v2 */
1305
1306 /* At this point: if PROXYv2, we've read the exact size required for all data;
1307 if PROXYv1 then we've read "less than required for any valid line" and should
1308 read the rest". */
1309
1310 if (ret >= 16 && memcmp(&hdr.v2, v2sig, 12) == 0)
1311 {
1312 uint8_t cmd = (hdr.v2.ver_cmd & 0x0f);
1313
1314 switch (cmd)
1315 {
1316 case 0x01: /* PROXY command */
1317 switch (hdr.v2.fam)
1318 {
1319 case 0x11: /* TCPv4 address type */
1320 iptype = US"IPv4";
1321 tmpaddr.sin_addr.s_addr = hdr.v2.addr.ip4.src_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 source IP\n", iptype);
1326 goto proxyfail;
1327 }
1328 proxy_local_address = sender_host_address;
1329 sender_host_address = string_copy(US tmpip);
1330 tmpport = ntohs(hdr.v2.addr.ip4.src_port);
1331 proxy_local_port = sender_host_port;
1332 sender_host_port = tmpport;
1333 /* Save dest ip/port */
1334 tmpaddr.sin_addr.s_addr = hdr.v2.addr.ip4.dst_addr;
1335 inet_ntop(AF_INET, &tmpaddr.sin_addr, CS &tmpip, sizeof(tmpip));
1336 if (!string_is_ip_address(US tmpip, NULL))
1337 {
1338 DEBUG(D_receive) debug_printf("Invalid %s dest port\n", iptype);
1339 goto proxyfail;
1340 }
1341 proxy_external_address = string_copy(US tmpip);
1342 tmpport = ntohs(hdr.v2.addr.ip4.dst_port);
1343 proxy_external_port = tmpport;
1344 goto done;
1345 case 0x21: /* TCPv6 address type */
1346 iptype = US"IPv6";
1347 memmove(tmpaddr6.sin6_addr.s6_addr, hdr.v2.addr.ip6.src_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 source IP\n", iptype);
1352 goto proxyfail;
1353 }
1354 proxy_local_address = sender_host_address;
1355 sender_host_address = string_copy(US tmpip6);
1356 tmpport = ntohs(hdr.v2.addr.ip6.src_port);
1357 proxy_local_port = sender_host_port;
1358 sender_host_port = tmpport;
1359 /* Save dest ip/port */
1360 memmove(tmpaddr6.sin6_addr.s6_addr, hdr.v2.addr.ip6.dst_addr, 16);
1361 inet_ntop(AF_INET6, &tmpaddr6.sin6_addr, CS &tmpip6, sizeof(tmpip6));
1362 if (!string_is_ip_address(US tmpip6, NULL))
1363 {
1364 DEBUG(D_receive) debug_printf("Invalid %s dest port\n", iptype);
1365 goto proxyfail;
1366 }
1367 proxy_external_address = string_copy(US tmpip6);
1368 tmpport = ntohs(hdr.v2.addr.ip6.dst_port);
1369 proxy_external_port = tmpport;
1370 goto done;
1371 default:
1372 DEBUG(D_receive)
1373 debug_printf("Unsupported PROXYv2 connection type: 0x%02x\n",
1374 hdr.v2.fam);
1375 goto proxyfail;
1376 }
1377 /* Unsupported protocol, keep local connection address */
1378 break;
1379 case 0x00: /* LOCAL command */
1380 /* Keep local connection address for LOCAL */
1381 iptype = US"local";
1382 break;
1383 default:
1384 DEBUG(D_receive)
1385 debug_printf("Unsupported PROXYv2 command: 0x%x\n", cmd);
1386 goto proxyfail;
1387 }
1388 }
1389 else if (ret >= 8 && memcmp(hdr.v1.line, "PROXY", 5) == 0)
1390 {
1391 uschar *p;
1392 uschar *end;
1393 uschar *sp; /* Utility variables follow */
1394 int tmp_port;
1395 int r2;
1396 char *endc;
1397
1398 /* get the rest of the line */
1399 r2 = swallow_until_crlf(fd, (uschar*)&hdr, ret, sizeof(hdr)-ret);
1400 if (r2 == -1)
1401 goto proxyfail;
1402 ret += r2;
1403
1404 p = string_copy(hdr.v1.line);
1405 end = memchr(p, '\r', ret - 1);
1406
1407 if (!end || (end == (uschar*)&hdr + ret) || end[1] != '\n')
1408 {
1409 DEBUG(D_receive) debug_printf("Partial or invalid PROXY header\n");
1410 goto proxyfail;
1411 }
1412 *end = '\0'; /* Terminate the string */
1413 size = end + 2 - p; /* Skip header + CRLF */
1414 DEBUG(D_receive) debug_printf("Detected PROXYv1 header\n");
1415 DEBUG(D_receive) debug_printf("Bytes read not within PROXY header: %d\n", ret - size);
1416 /* Step through the string looking for the required fields. Ensure
1417 strict adherence to required formatting, exit for any error. */
1418 p += 5;
1419 if (!isspace(*(p++)))
1420 {
1421 DEBUG(D_receive) debug_printf("Missing space after PROXY command\n");
1422 goto proxyfail;
1423 }
1424 if (!Ustrncmp(p, CCS"TCP4", 4))
1425 iptype = US"IPv4";
1426 else if (!Ustrncmp(p,CCS"TCP6", 4))
1427 iptype = US"IPv6";
1428 else if (!Ustrncmp(p,CCS"UNKNOWN", 7))
1429 {
1430 iptype = US"Unknown";
1431 goto done;
1432 }
1433 else
1434 {
1435 DEBUG(D_receive) debug_printf("Invalid TCP type\n");
1436 goto proxyfail;
1437 }
1438
1439 p += Ustrlen(iptype);
1440 if (!isspace(*(p++)))
1441 {
1442 DEBUG(D_receive) debug_printf("Missing space after TCP4/6 command\n");
1443 goto proxyfail;
1444 }
1445 /* Find the end of the arg */
1446 if ((sp = Ustrchr(p, ' ')) == NULL)
1447 {
1448 DEBUG(D_receive)
1449 debug_printf("Did not find proxied src %s\n", iptype);
1450 goto proxyfail;
1451 }
1452 *sp = '\0';
1453 if(!string_is_ip_address(p, NULL))
1454 {
1455 DEBUG(D_receive)
1456 debug_printf("Proxied src arg is not an %s address\n", iptype);
1457 goto proxyfail;
1458 }
1459 proxy_local_address = sender_host_address;
1460 sender_host_address = p;
1461 p = sp + 1;
1462 if ((sp = Ustrchr(p, ' ')) == NULL)
1463 {
1464 DEBUG(D_receive)
1465 debug_printf("Did not find proxy dest %s\n", iptype);
1466 goto proxyfail;
1467 }
1468 *sp = '\0';
1469 if(!string_is_ip_address(p, NULL))
1470 {
1471 DEBUG(D_receive)
1472 debug_printf("Proxy dest arg is not an %s address\n", iptype);
1473 goto proxyfail;
1474 }
1475 proxy_external_address = p;
1476 p = sp + 1;
1477 if ((sp = Ustrchr(p, ' ')) == NULL)
1478 {
1479 DEBUG(D_receive) debug_printf("Did not find proxied src port\n");
1480 goto proxyfail;
1481 }
1482 *sp = '\0';
1483 tmp_port = strtol(CCS p, &endc, 10);
1484 if (*endc || tmp_port == 0)
1485 {
1486 DEBUG(D_receive)
1487 debug_printf("Proxied src port '%s' not an integer\n", p);
1488 goto proxyfail;
1489 }
1490 proxy_local_port = sender_host_port;
1491 sender_host_port = tmp_port;
1492 p = sp + 1;
1493 if ((sp = Ustrchr(p, '\0')) == NULL)
1494 {
1495 DEBUG(D_receive) debug_printf("Did not find proxy dest port\n");
1496 goto proxyfail;
1497 }
1498 tmp_port = strtol(CCS p, &endc, 10);
1499 if (*endc || tmp_port == 0)
1500 {
1501 DEBUG(D_receive)
1502 debug_printf("Proxy dest port '%s' not an integer\n", p);
1503 goto proxyfail;
1504 }
1505 proxy_external_port = tmp_port;
1506 /* Already checked for /r /n above. Good V1 header received. */
1507 }
1508 else
1509 {
1510 /* Wrong protocol */
1511 DEBUG(D_receive) debug_printf("Invalid proxy protocol version negotiation\n");
1512 (void) swallow_until_crlf(fd, (uschar*)&hdr, ret, sizeof(hdr)-ret);
1513 goto proxyfail;
1514 }
1515
1516 done:
1517 DEBUG(D_receive)
1518 debug_printf("Valid %s sender from Proxy Protocol header\n", iptype);
1519 yield = proxy_session;
1520
1521 /* Don't flush any potential buffer contents. Any input on proxyfail
1522 should cause a synchronization failure */
1523
1524 proxyfail:
1525 restore_socket_timeout(fd, get_ok, &tvtmp, vslen);
1526
1527 bad:
1528 if (yield)
1529 {
1530 sender_host_name = NULL;
1531 (void) host_name_lookup();
1532 host_build_sender_fullhost();
1533 }
1534 else
1535 {
1536 f.proxy_session_failed = TRUE;
1537 DEBUG(D_receive)
1538 debug_printf("Failure to extract proxied host, only QUIT allowed\n");
1539 }
1540
1541 return;
1542 }
1543 #endif
1544
1545 /*************************************************
1546 * Read one command line *
1547 *************************************************/
1548
1549 /* Strictly, SMTP commands coming over the net are supposed to end with CRLF.
1550 There are sites that don't do this, and in any case internal SMTP probably
1551 should check only for LF. Consequently, we check here for LF only. The line
1552 ends up with [CR]LF removed from its end. If we get an overlong line, treat as
1553 an unknown command. The command is read into the global smtp_cmd_buffer so that
1554 it is available via $smtp_command.
1555
1556 The character reading routine sets up a timeout for each block actually read
1557 from the input (which may contain more than one command). We set up a special
1558 signal handler that closes down the session on a timeout. Control does not
1559 return when it runs.
1560
1561 Arguments:
1562 check_sync if TRUE, check synchronization rules if global option is TRUE
1563 buffer_lim maximum to buffer in lower layer
1564
1565 Returns: a code identifying the command (enumerated above)
1566 */
1567
1568 static int
1569 smtp_read_command(BOOL check_sync, unsigned buffer_lim)
1570 {
1571 int c;
1572 int ptr = 0;
1573 BOOL hadnull = FALSE;
1574
1575 had_command_timeout = 0;
1576 os_non_restarting_signal(SIGALRM, command_timeout_handler);
1577
1578 while ((c = (receive_getc)(buffer_lim)) != '\n' && c != EOF)
1579 {
1580 if (ptr >= SMTP_CMD_BUFFER_SIZE)
1581 {
1582 os_non_restarting_signal(SIGALRM, sigalrm_handler);
1583 return OTHER_CMD;
1584 }
1585 if (c == 0)
1586 {
1587 hadnull = TRUE;
1588 c = '?';
1589 }
1590 smtp_cmd_buffer[ptr++] = c;
1591 }
1592
1593 receive_linecount++; /* For BSMTP errors */
1594 os_non_restarting_signal(SIGALRM, sigalrm_handler);
1595
1596 /* If hit end of file, return pseudo EOF command. Whether we have a
1597 part-line already read doesn't matter, since this is an error state. */
1598
1599 if (c == EOF) return EOF_CMD;
1600
1601 /* Remove any CR and white space at the end of the line, and terminate the
1602 string. */
1603
1604 while (ptr > 0 && isspace(smtp_cmd_buffer[ptr-1])) ptr--;
1605 smtp_cmd_buffer[ptr] = 0;
1606
1607 DEBUG(D_receive) debug_printf("SMTP<< %s\n", smtp_cmd_buffer);
1608
1609 /* NULLs are not allowed in SMTP commands */
1610
1611 if (hadnull) return BADCHAR_CMD;
1612
1613 /* Scan command list and return identity, having set the data pointer
1614 to the start of the actual data characters. Check for SMTP synchronization
1615 if required. */
1616
1617 for (smtp_cmd_list * p = cmd_list; p < cmd_list_end; p++)
1618 {
1619 #ifdef SUPPORT_PROXY
1620 /* Only allow QUIT command if Proxy Protocol parsing failed */
1621 if (proxy_session && f.proxy_session_failed && p->cmd != QUIT_CMD)
1622 continue;
1623 #endif
1624 if ( p->len
1625 && strncmpic(smtp_cmd_buffer, US p->name, p->len) == 0
1626 && ( smtp_cmd_buffer[p->len-1] == ':' /* "mail from:" or "rcpt to:" */
1627 || smtp_cmd_buffer[p->len] == 0
1628 || smtp_cmd_buffer[p->len] == ' '
1629 ) )
1630 {
1631 if (smtp_inptr < smtp_inend && /* Outstanding input */
1632 p->cmd < sync_cmd_limit && /* Command should sync */
1633 check_sync && /* Local flag set */
1634 smtp_enforce_sync && /* Global flag set */
1635 sender_host_address != NULL && /* Not local input */
1636 !f.sender_host_notsocket) /* Really is a socket */
1637 return BADSYN_CMD;
1638
1639 /* The variables $smtp_command and $smtp_command_argument point into the
1640 unmodified input buffer. A copy of the latter is taken for actual
1641 processing, so that it can be chopped up into separate parts if necessary,
1642 for example, when processing a MAIL command options such as SIZE that can
1643 follow the sender address. */
1644
1645 smtp_cmd_argument = smtp_cmd_buffer + p->len;
1646 while (isspace(*smtp_cmd_argument)) smtp_cmd_argument++;
1647 Ustrcpy(smtp_data_buffer, smtp_cmd_argument);
1648 smtp_cmd_data = smtp_data_buffer;
1649
1650 /* Count non-mail commands from those hosts that are controlled in this
1651 way. The default is all hosts. We don't waste effort checking the list
1652 until we get a non-mail command, but then cache the result to save checking
1653 again. If there's a DEFER while checking the host, assume it's in the list.
1654
1655 Note that one instance of RSET, EHLO/HELO, and STARTTLS is allowed at the
1656 start of each incoming message by fiddling with the value in the table. */
1657
1658 if (!p->is_mail_cmd)
1659 {
1660 if (count_nonmail == TRUE_UNSET) count_nonmail =
1661 verify_check_host(&smtp_accept_max_nonmail_hosts) != FAIL;
1662 if (count_nonmail && ++nonmail_command_count > smtp_accept_max_nonmail)
1663 return TOO_MANY_NONMAIL_CMD;
1664 }
1665
1666 /* If there is data for a command that does not expect it, generate the
1667 error here. */
1668
1669 return (p->has_arg || *smtp_cmd_data == 0)? p->cmd : BADARG_CMD;
1670 }
1671 }
1672
1673 #ifdef SUPPORT_PROXY
1674 /* Only allow QUIT command if Proxy Protocol parsing failed */
1675 if (proxy_session && f.proxy_session_failed)
1676 return PROXY_FAIL_IGNORE_CMD;
1677 #endif
1678
1679 /* Enforce synchronization for unknown commands */
1680
1681 if ( smtp_inptr < smtp_inend /* Outstanding input */
1682 && check_sync /* Local flag set */
1683 && smtp_enforce_sync /* Global flag set */
1684 && sender_host_address /* Not local input */
1685 && !f.sender_host_notsocket) /* Really is a socket */
1686 return BADSYN_CMD;
1687
1688 return OTHER_CMD;
1689 }
1690
1691
1692
1693 /*************************************************
1694 * Forced closedown of call *
1695 *************************************************/
1696
1697 /* This function is called from log.c when Exim is dying because of a serious
1698 disaster, and also from some other places. If an incoming non-batched SMTP
1699 channel is open, it swallows the rest of the incoming message if in the DATA
1700 phase, sends the reply string, and gives an error to all subsequent commands
1701 except QUIT. The existence of an SMTP call is detected by the non-NULLness of
1702 smtp_in.
1703
1704 Arguments:
1705 message SMTP reply string to send, excluding the code
1706
1707 Returns: nothing
1708 */
1709
1710 void
1711 smtp_closedown(uschar *message)
1712 {
1713 if (!smtp_in || smtp_batched_input) return;
1714 receive_swallow_smtp();
1715 smtp_printf("421 %s\r\n", FALSE, message);
1716
1717 for (;;) switch(smtp_read_command(FALSE, GETC_BUFFER_UNLIMITED))
1718 {
1719 case EOF_CMD:
1720 return;
1721
1722 case QUIT_CMD:
1723 smtp_printf("221 %s closing connection\r\n", FALSE, smtp_active_hostname);
1724 mac_smtp_fflush();
1725 return;
1726
1727 case RSET_CMD:
1728 smtp_printf("250 Reset OK\r\n", FALSE);
1729 break;
1730
1731 default:
1732 smtp_printf("421 %s\r\n", FALSE, message);
1733 break;
1734 }
1735 }
1736
1737
1738
1739
1740 /*************************************************
1741 * Set up connection info for logging *
1742 *************************************************/
1743
1744 /* This function is called when logging information about an SMTP connection.
1745 It sets up appropriate source information, depending on the type of connection.
1746 If sender_fullhost is NULL, we are at a very early stage of the connection;
1747 just use the IP address.
1748
1749 Argument: none
1750 Returns: a string describing the connection
1751 */
1752
1753 uschar *
1754 smtp_get_connection_info(void)
1755 {
1756 const uschar * hostname = sender_fullhost
1757 ? sender_fullhost : sender_host_address;
1758
1759 if (host_checking)
1760 return string_sprintf("SMTP connection from %s", hostname);
1761
1762 if (f.sender_host_unknown || f.sender_host_notsocket)
1763 return string_sprintf("SMTP connection from %s", sender_ident);
1764
1765 if (f.is_inetd)
1766 return string_sprintf("SMTP connection from %s (via inetd)", hostname);
1767
1768 if (LOGGING(incoming_interface) && interface_address)
1769 return string_sprintf("SMTP connection from %s I=[%s]:%d", hostname,
1770 interface_address, interface_port);
1771
1772 return string_sprintf("SMTP connection from %s", hostname);
1773 }
1774
1775
1776
1777 #ifdef SUPPORT_TLS
1778 /* Append TLS-related information to a log line
1779
1780 Arguments:
1781 g String under construction: allocated string to extend, or NULL
1782
1783 Returns: Allocated string or NULL
1784 */
1785 static gstring *
1786 s_tlslog(gstring * g)
1787 {
1788 if (LOGGING(tls_cipher) && tls_in.cipher)
1789 {
1790 g = string_append(g, 2, US" X=", tls_in.cipher);
1791 #ifdef EXPERIMENTAL_TLS_RESUME
1792 if (LOGGING(tls_resumption) && tls_in.resumption & RESUME_USED)
1793 g = string_catn(g, US"*", 1);
1794 #endif
1795 }
1796 if (LOGGING(tls_certificate_verified) && tls_in.cipher)
1797 g = string_append(g, 2, US" CV=", tls_in.certificate_verified? "yes":"no");
1798 if (LOGGING(tls_peerdn) && tls_in.peerdn)
1799 g = string_append(g, 3, US" DN=\"", string_printing(tls_in.peerdn), US"\"");
1800 if (LOGGING(tls_sni) && tls_in.sni)
1801 g = string_append(g, 3, US" SNI=\"", string_printing(tls_in.sni), US"\"");
1802 return g;
1803 }
1804 #endif
1805
1806 /*************************************************
1807 * Log lack of MAIL if so configured *
1808 *************************************************/
1809
1810 /* This function is called when an SMTP session ends. If the log selector
1811 smtp_no_mail is set, write a log line giving some details of what has happened
1812 in the SMTP session.
1813
1814 Arguments: none
1815 Returns: nothing
1816 */
1817
1818 void
1819 smtp_log_no_mail(void)
1820 {
1821 uschar * sep, * s;
1822 gstring * g = NULL;
1823
1824 if (smtp_mailcmd_count > 0 || !LOGGING(smtp_no_mail))
1825 return;
1826
1827 if (sender_host_authenticated)
1828 {
1829 g = string_append(g, 2, US" A=", sender_host_authenticated);
1830 if (authenticated_id) g = string_append(g, 2, US":", authenticated_id);
1831 }
1832
1833 #ifdef SUPPORT_TLS
1834 g = s_tlslog(g);
1835 #endif
1836
1837 sep = smtp_connection_had[SMTP_HBUFF_SIZE-1] != SCH_NONE ? US" C=..." : US" C=";
1838
1839 for (int i = smtp_ch_index; i < SMTP_HBUFF_SIZE; i++)
1840 if (smtp_connection_had[i] != SCH_NONE)
1841 {
1842 g = string_append(g, 2, sep, smtp_names[smtp_connection_had[i]]);
1843 sep = US",";
1844 }
1845
1846 for (int i = 0; i < smtp_ch_index; i++)
1847 {
1848 g = string_append(g, 2, sep, smtp_names[smtp_connection_had[i]]);
1849 sep = US",";
1850 }
1851
1852 if (!(s = string_from_gstring(g))) s = US"";
1853
1854 log_write(0, LOG_MAIN, "no MAIL in %sSMTP connection from %s D=%s%s",
1855 f.tcp_in_fastopen ? f.tcp_in_fastopen_data ? US"TFO* " : US"TFO " : US"",
1856 host_and_ident(FALSE), string_timesince(&smtp_connection_start), s);
1857 }
1858
1859
1860 /* Return list of recent smtp commands */
1861
1862 uschar *
1863 smtp_cmd_hist(void)
1864 {
1865 gstring * list = NULL;
1866 uschar * s;
1867
1868 for (int i = smtp_ch_index; i < SMTP_HBUFF_SIZE; i++)
1869 if (smtp_connection_had[i] != SCH_NONE)
1870 list = string_append_listele(list, ',', smtp_names[smtp_connection_had[i]]);
1871
1872 for (int i = 0; i < smtp_ch_index; i++)
1873 list = string_append_listele(list, ',', smtp_names[smtp_connection_had[i]]);
1874
1875 s = string_from_gstring(list);
1876 return s ? s : US"";
1877 }
1878
1879
1880
1881
1882 /*************************************************
1883 * Check HELO line and set sender_helo_name *
1884 *************************************************/
1885
1886 /* Check the format of a HELO line. The data for HELO/EHLO is supposed to be
1887 the domain name of the sending host, or an ip literal in square brackets. The
1888 argument is placed in sender_helo_name, which is in malloc store, because it
1889 must persist over multiple incoming messages. If helo_accept_junk is set, this
1890 host is permitted to send any old junk (needed for some broken hosts).
1891 Otherwise, helo_allow_chars can be used for rogue characters in general
1892 (typically people want to let in underscores).
1893
1894 Argument:
1895 s the data portion of the line (already past any white space)
1896
1897 Returns: TRUE or FALSE
1898 */
1899
1900 static BOOL
1901 check_helo(uschar *s)
1902 {
1903 uschar *start = s;
1904 uschar *end = s + Ustrlen(s);
1905 BOOL yield = fl.helo_accept_junk;
1906
1907 /* Discard any previous helo name */
1908
1909 if (sender_helo_name)
1910 {
1911 store_free(sender_helo_name);
1912 sender_helo_name = NULL;
1913 }
1914
1915 /* Skip tests if junk is permitted. */
1916
1917 if (!yield)
1918
1919 /* Allow the new standard form for IPv6 address literals, namely,
1920 [IPv6:....], and because someone is bound to use it, allow an equivalent
1921 IPv4 form. Allow plain addresses as well. */
1922
1923 if (*s == '[')
1924 {
1925 if (end[-1] == ']')
1926 {
1927 end[-1] = 0;
1928 if (strncmpic(s, US"[IPv6:", 6) == 0)
1929 yield = (string_is_ip_address(s+6, NULL) == 6);
1930 else if (strncmpic(s, US"[IPv4:", 6) == 0)
1931 yield = (string_is_ip_address(s+6, NULL) == 4);
1932 else
1933 yield = (string_is_ip_address(s+1, NULL) != 0);
1934 end[-1] = ']';
1935 }
1936 }
1937
1938 /* Non-literals must be alpha, dot, hyphen, plus any non-valid chars
1939 that have been configured (usually underscore - sigh). */
1940
1941 else if (*s)
1942 for (yield = TRUE; *s; s++)
1943 if (!isalnum(*s) && *s != '.' && *s != '-' &&
1944 Ustrchr(helo_allow_chars, *s) == NULL)
1945 {
1946 yield = FALSE;
1947 break;
1948 }
1949
1950 /* Save argument if OK */
1951
1952 if (yield) sender_helo_name = string_copy_malloc(start);
1953 return yield;
1954 }
1955
1956
1957
1958
1959
1960 /*************************************************
1961 * Extract SMTP command option *
1962 *************************************************/
1963
1964 /* This function picks the next option setting off the end of smtp_cmd_data. It
1965 is called for MAIL FROM and RCPT TO commands, to pick off the optional ESMTP
1966 things that can appear there.
1967
1968 Arguments:
1969 name point this at the name
1970 value point this at the data string
1971
1972 Returns: TRUE if found an option
1973 */
1974
1975 static BOOL
1976 extract_option(uschar **name, uschar **value)
1977 {
1978 uschar *n;
1979 uschar *v = smtp_cmd_data + Ustrlen(smtp_cmd_data) - 1;
1980 while (isspace(*v)) v--;
1981 v[1] = 0;
1982 while (v > smtp_cmd_data && *v != '=' && !isspace(*v))
1983 {
1984 /* Take care to not stop at a space embedded in a quoted local-part */
1985
1986 if (*v == '"') do v--; while (*v != '"' && v > smtp_cmd_data+1);
1987 v--;
1988 }
1989
1990 n = v;
1991 if (*v == '=')
1992 {
1993 while(isalpha(n[-1])) n--;
1994 /* RFC says SP, but TAB seen in wild and other major MTAs accept it */
1995 if (!isspace(n[-1])) return FALSE;
1996 n[-1] = 0;
1997 }
1998 else
1999 {
2000 n++;
2001 if (v == smtp_cmd_data) return FALSE;
2002 }
2003 *v++ = 0;
2004 *name = n;
2005 *value = v;
2006 return TRUE;
2007 }
2008
2009
2010
2011
2012
2013 /*************************************************
2014 * Reset for new message *
2015 *************************************************/
2016
2017 /* This function is called whenever the SMTP session is reset from
2018 within either of the setup functions; also from the daemon loop.
2019
2020 Argument: the stacking pool storage reset point
2021 Returns: nothing
2022 */
2023
2024 void
2025 smtp_reset(void *reset_point)
2026 {
2027 recipients_list = NULL;
2028 rcpt_count = rcpt_defer_count = rcpt_fail_count =
2029 raw_recipients_count = recipients_count = recipients_list_max = 0;
2030 message_linecount = 0;
2031 message_size = -1;
2032 acl_added_headers = NULL;
2033 acl_removed_headers = NULL;
2034 f.queue_only_policy = FALSE;
2035 rcpt_smtp_response = NULL;
2036 fl.rcpt_smtp_response_same = TRUE;
2037 fl.rcpt_in_progress = FALSE;
2038 f.deliver_freeze = FALSE; /* Can be set by ACL */
2039 freeze_tell = freeze_tell_config; /* Can be set by ACL */
2040 fake_response = OK; /* Can be set by ACL */
2041 #ifdef WITH_CONTENT_SCAN
2042 f.no_mbox_unspool = FALSE; /* Can be set by ACL */
2043 #endif
2044 f.submission_mode = FALSE; /* Can be set by ACL */
2045 f.suppress_local_fixups = f.suppress_local_fixups_default; /* Can be set by ACL */
2046 f.active_local_from_check = local_from_check; /* Can be set by ACL */
2047 f.active_local_sender_retain = local_sender_retain; /* Can be set by ACL */
2048 sending_ip_address = NULL;
2049 return_path = sender_address = NULL;
2050 sender_data = NULL; /* Can be set by ACL */
2051 deliver_localpart_parent = deliver_localpart_orig = NULL;
2052 deliver_domain_parent = deliver_domain_orig = NULL;
2053 callout_address = NULL;
2054 submission_name = NULL; /* Can be set by ACL */
2055 raw_sender = NULL; /* After SMTP rewrite, before qualifying */
2056 sender_address_unrewritten = NULL; /* Set only after verify rewrite */
2057 sender_verified_list = NULL; /* No senders verified */
2058 memset(sender_address_cache, 0, sizeof(sender_address_cache));
2059 memset(sender_domain_cache, 0, sizeof(sender_domain_cache));
2060
2061 authenticated_sender = NULL;
2062 #ifdef EXPERIMENTAL_BRIGHTMAIL
2063 bmi_run = 0;
2064 bmi_verdicts = NULL;
2065 #endif
2066 dnslist_domain = dnslist_matched = NULL;
2067 #ifdef SUPPORT_SPF
2068 spf_header_comment = spf_received = spf_result = spf_smtp_comment = NULL;
2069 spf_result_guessed = FALSE;
2070 #endif
2071 #ifndef DISABLE_DKIM
2072 dkim_cur_signer = dkim_signers =
2073 dkim_signing_domain = dkim_signing_selector = dkim_signatures = NULL;
2074 dkim_cur_signer = dkim_signers = dkim_signing_domain = dkim_signing_selector = NULL;
2075 f.dkim_disable_verify = FALSE;
2076 dkim_collect_input = 0;
2077 dkim_verify_overall = dkim_verify_status = dkim_verify_reason = NULL;
2078 dkim_key_length = 0;
2079 #endif
2080 #ifdef EXPERIMENTAL_DMARC
2081 f.dmarc_has_been_checked = f.dmarc_disable_verify = f.dmarc_enable_forensic = FALSE;
2082 dmarc_domain_policy = dmarc_status = dmarc_status_text =
2083 dmarc_used_domain = NULL;
2084 #endif
2085 #ifdef EXPERIMENTAL_ARC
2086 arc_state = arc_state_reason = NULL;
2087 #endif
2088 dsn_ret = 0;
2089 dsn_envid = NULL;
2090 deliver_host = deliver_host_address = NULL; /* Can be set by ACL */
2091 #ifndef DISABLE_PRDR
2092 prdr_requested = FALSE;
2093 #endif
2094 #ifdef SUPPORT_I18N
2095 message_smtputf8 = FALSE;
2096 #endif
2097 body_linecount = body_zerocount = 0;
2098
2099 sender_rate = sender_rate_limit = sender_rate_period = NULL;
2100 ratelimiters_mail = NULL; /* Updated by ratelimit ACL condition */
2101 /* Note that ratelimiters_conn persists across resets. */
2102
2103 /* Reset message ACL variables */
2104
2105 acl_var_m = NULL;
2106
2107 /* The message body variables use malloc store. They may be set if this is
2108 not the first message in an SMTP session and the previous message caused them
2109 to be referenced in an ACL. */
2110
2111 if (message_body)
2112 {
2113 store_free(message_body);
2114 message_body = NULL;
2115 }
2116
2117 if (message_body_end)
2118 {
2119 store_free(message_body_end);
2120 message_body_end = NULL;
2121 }
2122
2123 /* Warning log messages are also saved in malloc store. They are saved to avoid
2124 repetition in the same message, but it seems right to repeat them for different
2125 messages. */
2126
2127 while (acl_warn_logged)
2128 {
2129 string_item *this = acl_warn_logged;
2130 acl_warn_logged = acl_warn_logged->next;
2131 store_free(this);
2132 }
2133 store_reset(reset_point);
2134 }
2135
2136
2137
2138
2139
2140 /*************************************************
2141 * Initialize for incoming batched SMTP message *
2142 *************************************************/
2143
2144 /* This function is called from smtp_setup_msg() in the case when
2145 smtp_batched_input is true. This happens when -bS is used to pass a whole batch
2146 of messages in one file with SMTP commands between them. All errors must be
2147 reported by sending a message, and only MAIL FROM, RCPT TO, and DATA are
2148 relevant. After an error on a sender, or an invalid recipient, the remainder
2149 of the message is skipped. The value of received_protocol is already set.
2150
2151 Argument: none
2152 Returns: > 0 message successfully started (reached DATA)
2153 = 0 QUIT read or end of file reached
2154 < 0 should not occur
2155 */
2156
2157 static int
2158 smtp_setup_batch_msg(void)
2159 {
2160 int done = 0;
2161 void *reset_point = store_get(0);
2162
2163 /* Save the line count at the start of each transaction - single commands
2164 like HELO and RSET count as whole transactions. */
2165
2166 bsmtp_transaction_linecount = receive_linecount;
2167
2168 if ((receive_feof)()) return 0; /* Treat EOF as QUIT */
2169
2170 cancel_cutthrough_connection(TRUE, US"smtp_setup_batch_msg");
2171 smtp_reset(reset_point); /* Reset for start of message */
2172
2173 /* Deal with SMTP commands. This loop is exited by setting done to a POSITIVE
2174 value. The values are 2 larger than the required yield of the function. */
2175
2176 while (done <= 0)
2177 {
2178 uschar *errmess;
2179 uschar *recipient = NULL;
2180 int start, end, sender_domain, recipient_domain;
2181
2182 switch(smtp_read_command(FALSE, GETC_BUFFER_UNLIMITED))
2183 {
2184 /* The HELO/EHLO commands set sender_address_helo if they have
2185 valid data; otherwise they are ignored, except that they do
2186 a reset of the state. */
2187
2188 case HELO_CMD:
2189 case EHLO_CMD:
2190
2191 check_helo(smtp_cmd_data);
2192 /* Fall through */
2193
2194 case RSET_CMD:
2195 cancel_cutthrough_connection(TRUE, US"RSET received");
2196 smtp_reset(reset_point);
2197 bsmtp_transaction_linecount = receive_linecount;
2198 break;
2199
2200
2201 /* The MAIL FROM command requires an address as an operand. All we
2202 do here is to parse it for syntactic correctness. The form "<>" is
2203 a special case which converts into an empty string. The start/end
2204 pointers in the original are not used further for this address, as
2205 it is the canonical extracted address which is all that is kept. */
2206
2207 case MAIL_CMD:
2208 smtp_mailcmd_count++; /* Count for no-mail log */
2209 if (sender_address != NULL)
2210 /* The function moan_smtp_batch() does not return. */
2211 moan_smtp_batch(smtp_cmd_buffer, "503 Sender already given");
2212
2213 if (smtp_cmd_data[0] == 0)
2214 /* The function moan_smtp_batch() does not return. */
2215 moan_smtp_batch(smtp_cmd_buffer, "501 MAIL FROM must have an address operand");
2216
2217 /* Reset to start of message */
2218
2219 cancel_cutthrough_connection(TRUE, US"MAIL received");
2220 smtp_reset(reset_point);
2221
2222 /* Apply SMTP rewrite */
2223
2224 raw_sender = ((rewrite_existflags & rewrite_smtp) != 0)?
2225 rewrite_one(smtp_cmd_data, rewrite_smtp|rewrite_smtp_sender, NULL, FALSE,
2226 US"", global_rewrite_rules) : smtp_cmd_data;
2227
2228 /* Extract the address; the TRUE flag allows <> as valid */
2229
2230 raw_sender =
2231 parse_extract_address(raw_sender, &errmess, &start, &end, &sender_domain,
2232 TRUE);
2233
2234 if (!raw_sender)
2235 /* The function moan_smtp_batch() does not return. */
2236 moan_smtp_batch(smtp_cmd_buffer, "501 %s", errmess);
2237
2238 sender_address = string_copy(raw_sender);
2239
2240 /* Qualify unqualified sender addresses if permitted to do so. */
2241
2242 if ( !sender_domain
2243 && sender_address[0] != 0 && sender_address[0] != '@')
2244 if (f.allow_unqualified_sender)
2245 {
2246 sender_address = rewrite_address_qualify(sender_address, FALSE);
2247 DEBUG(D_receive) debug_printf("unqualified address %s accepted "
2248 "and rewritten\n", raw_sender);
2249 }
2250 /* The function moan_smtp_batch() does not return. */
2251 else
2252 moan_smtp_batch(smtp_cmd_buffer, "501 sender address must contain "
2253 "a domain");
2254 break;
2255
2256
2257 /* The RCPT TO command requires an address as an operand. All we do
2258 here is to parse it for syntactic correctness. There may be any number
2259 of RCPT TO commands, specifying multiple senders. We build them all into
2260 a data structure that is in argc/argv format. The start/end values
2261 given by parse_extract_address are not used, as we keep only the
2262 extracted address. */
2263
2264 case RCPT_CMD:
2265 if (!sender_address)
2266 /* The function moan_smtp_batch() does not return. */
2267 moan_smtp_batch(smtp_cmd_buffer, "503 No sender yet given");
2268
2269 if (smtp_cmd_data[0] == 0)
2270 /* The function moan_smtp_batch() does not return. */
2271 moan_smtp_batch(smtp_cmd_buffer,
2272 "501 RCPT TO must have an address operand");
2273
2274 /* Check maximum number allowed */
2275
2276 if (recipients_max > 0 && recipients_count + 1 > recipients_max)
2277 /* The function moan_smtp_batch() does not return. */
2278 moan_smtp_batch(smtp_cmd_buffer, "%s too many recipients",
2279 recipients_max_reject? "552": "452");
2280
2281 /* Apply SMTP rewrite, then extract address. Don't allow "<>" as a
2282 recipient address */
2283
2284 recipient = rewrite_existflags & rewrite_smtp
2285 ? rewrite_one(smtp_cmd_data, rewrite_smtp, NULL, FALSE, US"",
2286 global_rewrite_rules)
2287 : smtp_cmd_data;
2288
2289 recipient = parse_extract_address(recipient, &errmess, &start, &end,
2290 &recipient_domain, FALSE);
2291
2292 if (!recipient)
2293 /* The function moan_smtp_batch() does not return. */
2294 moan_smtp_batch(smtp_cmd_buffer, "501 %s", errmess);
2295
2296 /* If the recipient address is unqualified, qualify it if permitted. Then
2297 add it to the list of recipients. */
2298
2299 if (!recipient_domain)
2300 if (f.allow_unqualified_recipient)
2301 {
2302 DEBUG(D_receive) debug_printf("unqualified address %s accepted\n",
2303 recipient);
2304 recipient = rewrite_address_qualify(recipient, TRUE);
2305 }
2306 /* The function moan_smtp_batch() does not return. */
2307 else
2308 moan_smtp_batch(smtp_cmd_buffer,
2309 "501 recipient address must contain a domain");
2310
2311 receive_add_recipient(recipient, -1);
2312 break;
2313
2314
2315 /* The DATA command is legal only if it follows successful MAIL FROM
2316 and RCPT TO commands. This function is complete when a valid DATA
2317 command is encountered. */
2318
2319 case DATA_CMD:
2320 if (!sender_address || recipients_count <= 0)
2321 /* The function moan_smtp_batch() does not return. */
2322 if (!sender_address)
2323 moan_smtp_batch(smtp_cmd_buffer,
2324 "503 MAIL FROM:<sender> command must precede DATA");
2325 else
2326 moan_smtp_batch(smtp_cmd_buffer,
2327 "503 RCPT TO:<recipient> must precede DATA");
2328 else
2329 {
2330 done = 3; /* DATA successfully achieved */
2331 message_ended = END_NOTENDED; /* Indicate in middle of message */
2332 }
2333 break;
2334
2335
2336 /* The VRFY, EXPN, HELP, ETRN, and NOOP commands are ignored. */
2337
2338 case VRFY_CMD:
2339 case EXPN_CMD:
2340 case HELP_CMD:
2341 case NOOP_CMD:
2342 case ETRN_CMD:
2343 bsmtp_transaction_linecount = receive_linecount;
2344 break;
2345
2346
2347 case EOF_CMD:
2348 case QUIT_CMD:
2349 done = 2;
2350 break;
2351
2352
2353 case BADARG_CMD:
2354 /* The function moan_smtp_batch() does not return. */
2355 moan_smtp_batch(smtp_cmd_buffer, "501 Unexpected argument data");
2356 break;
2357
2358
2359 case BADCHAR_CMD:
2360 /* The function moan_smtp_batch() does not return. */
2361 moan_smtp_batch(smtp_cmd_buffer, "501 Unexpected NULL in SMTP command");
2362 break;
2363
2364
2365 default:
2366 /* The function moan_smtp_batch() does not return. */
2367 moan_smtp_batch(smtp_cmd_buffer, "500 Command unrecognized");
2368 break;
2369 }
2370 }
2371
2372 return done - 2; /* Convert yield values */
2373 }
2374
2375
2376
2377
2378 #ifdef SUPPORT_TLS
2379 static BOOL
2380 smtp_log_tls_fail(uschar * errstr)
2381 {
2382 uschar * conn_info = smtp_get_connection_info();
2383
2384 if (Ustrncmp(conn_info, US"SMTP ", 5) == 0) conn_info += 5;
2385 /* I'd like to get separated H= here, but too hard for now */
2386
2387 log_write(0, LOG_MAIN, "TLS error on %s %s", conn_info, errstr);
2388 return FALSE;
2389 }
2390 #endif
2391
2392
2393
2394
2395 #ifdef TCP_FASTOPEN
2396 static void
2397 tfo_in_check(void)
2398 {
2399 # ifdef TCP_INFO
2400 struct tcp_info tinfo;
2401 socklen_t len = sizeof(tinfo);
2402
2403 if (getsockopt(fileno(smtp_out), IPPROTO_TCP, TCP_INFO, &tinfo, &len) == 0)
2404 #ifdef TCPI_OPT_SYN_DATA /* FreeBSD 11 does not seem to have this yet */
2405 if (tinfo.tcpi_options & TCPI_OPT_SYN_DATA)
2406 {
2407 DEBUG(D_receive) debug_printf("TCP_FASTOPEN mode connection (ACKd data-on-SYN)\n");
2408 f.tcp_in_fastopen_data = f.tcp_in_fastopen = TRUE;
2409 }
2410 else
2411 #endif
2412 if (tinfo.tcpi_state == TCP_SYN_RECV)
2413 {
2414 DEBUG(D_receive) debug_printf("TCP_FASTOPEN mode connection (state TCP_SYN_RECV)\n");
2415 f.tcp_in_fastopen = TRUE;
2416 }
2417 # endif
2418 }
2419 #endif
2420
2421
2422 /*************************************************
2423 * Start an SMTP session *
2424 *************************************************/
2425
2426 /* This function is called at the start of an SMTP session. Thereafter,
2427 smtp_setup_msg() is called to initiate each separate message. This
2428 function does host-specific testing, and outputs the banner line.
2429
2430 Arguments: none
2431 Returns: FALSE if the session can not continue; something has
2432 gone wrong, or the connection to the host is blocked
2433 */
2434
2435 BOOL
2436 smtp_start_session(void)
2437 {
2438 int esclen;
2439 uschar *user_msg, *log_msg;
2440 uschar *code, *esc;
2441 uschar *p, *s;
2442 gstring * ss;
2443
2444 gettimeofday(&smtp_connection_start, NULL);
2445 for (smtp_ch_index = 0; smtp_ch_index < SMTP_HBUFF_SIZE; smtp_ch_index++)
2446 smtp_connection_had[smtp_ch_index] = SCH_NONE;
2447 smtp_ch_index = 0;
2448
2449 /* Default values for certain variables */
2450
2451 fl.helo_seen = fl.esmtp = fl.helo_accept_junk = FALSE;
2452 smtp_mailcmd_count = 0;
2453 count_nonmail = TRUE_UNSET;
2454 synprot_error_count = unknown_command_count = nonmail_command_count = 0;
2455 smtp_delay_mail = smtp_rlm_base;
2456 fl.auth_advertised = FALSE;
2457 f.smtp_in_pipelining_advertised = f.smtp_in_pipelining_used = FALSE;
2458 f.pipelining_enable = TRUE;
2459 sync_cmd_limit = NON_SYNC_CMD_NON_PIPELINING;
2460 fl.smtp_exit_function_called = FALSE; /* For avoiding loop in not-quit exit */
2461
2462 /* If receiving by -bs from a trusted user, or testing with -bh, we allow
2463 authentication settings from -oMaa to remain in force. */
2464
2465 if (!host_checking && !f.sender_host_notsocket)
2466 sender_host_auth_pubname = sender_host_authenticated = NULL;
2467 authenticated_by = NULL;
2468
2469 #ifdef SUPPORT_TLS
2470 tls_in.cipher = tls_in.peerdn = NULL;
2471 tls_in.ourcert = tls_in.peercert = NULL;
2472 tls_in.sni = NULL;
2473 tls_in.ocsp = OCSP_NOT_REQ;
2474 fl.tls_advertised = FALSE;
2475 #endif
2476 fl.dsn_advertised = FALSE;
2477 #ifdef SUPPORT_I18N
2478 fl.smtputf8_advertised = FALSE;
2479 #endif
2480
2481 /* Reset ACL connection variables */
2482
2483 acl_var_c = NULL;
2484
2485 /* Allow for trailing 0 in the command and data buffers. */
2486
2487 if (!(smtp_cmd_buffer = US malloc(2*SMTP_CMD_BUFFER_SIZE + 2)))
2488 log_write(0, LOG_MAIN|LOG_PANIC_DIE,
2489 "malloc() failed for SMTP command buffer");
2490
2491 smtp_cmd_buffer[0] = 0;
2492 smtp_data_buffer = smtp_cmd_buffer + SMTP_CMD_BUFFER_SIZE + 1;
2493
2494 /* For batched input, the protocol setting can be overridden from the
2495 command line by a trusted caller. */
2496
2497 if (smtp_batched_input)
2498 {
2499 if (!received_protocol) received_protocol = US"local-bsmtp";
2500 }
2501
2502 /* For non-batched SMTP input, the protocol setting is forced here. It will be
2503 reset later if any of EHLO/AUTH/STARTTLS are received. */
2504
2505 else
2506 received_protocol =
2507 (sender_host_address ? protocols : protocols_local) [pnormal];
2508
2509 /* Set up the buffer for inputting using direct read() calls, and arrange to
2510 call the local functions instead of the standard C ones. Place a NUL at the
2511 end of the buffer to safety-stop C-string reads from it. */
2512
2513 if (!(smtp_inbuffer = US malloc(IN_BUFFER_SIZE)))
2514 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "malloc() failed for SMTP input buffer");
2515 smtp_inbuffer[IN_BUFFER_SIZE-1] = '\0';
2516
2517 receive_getc = smtp_getc;
2518 receive_getbuf = smtp_getbuf;
2519 receive_get_cache = smtp_get_cache;
2520 receive_ungetc = smtp_ungetc;
2521 receive_feof = smtp_feof;
2522 receive_ferror = smtp_ferror;
2523 receive_smtp_buffered = smtp_buffered;
2524 smtp_inptr = smtp_inend = smtp_inbuffer;
2525 smtp_had_eof = smtp_had_error = 0;
2526
2527 /* Set up the message size limit; this may be host-specific */
2528
2529 thismessage_size_limit = expand_string_integer(message_size_limit, TRUE);
2530 if (expand_string_message)
2531 {
2532 if (thismessage_size_limit == -1)
2533 log_write(0, LOG_MAIN|LOG_PANIC, "unable to expand message_size_limit: "
2534 "%s", expand_string_message);
2535 else
2536 log_write(0, LOG_MAIN|LOG_PANIC, "invalid message_size_limit: "
2537 "%s", expand_string_message);
2538 smtp_closedown(US"Temporary local problem - please try later");
2539 return FALSE;
2540 }
2541
2542 /* When a message is input locally via the -bs or -bS options, sender_host_
2543 unknown is set unless -oMa was used to force an IP address, in which case it
2544 is checked like a real remote connection. When -bs is used from inetd, this
2545 flag is not set, causing the sending host to be checked. The code that deals
2546 with IP source routing (if configured) is never required for -bs or -bS and
2547 the flag sender_host_notsocket is used to suppress it.
2548
2549 If smtp_accept_max and smtp_accept_reserve are set, keep some connections in
2550 reserve for certain hosts and/or networks. */
2551
2552 if (!f.sender_host_unknown)
2553 {
2554 int rc;
2555 BOOL reserved_host = FALSE;
2556
2557 /* Look up IP options (source routing info) on the socket if this is not an
2558 -oMa "host", and if any are found, log them and drop the connection.
2559
2560 Linux (and others now, see below) is different to everyone else, so there
2561 has to be some conditional compilation here. Versions of Linux before 2.1.15
2562 used a structure whose name was "options". Somebody finally realized that
2563 this name was silly, and it got changed to "ip_options". I use the
2564 newer name here, but there is a fudge in the script that sets up os.h
2565 to define a macro in older Linux systems.
2566
2567 Sigh. Linux is a fast-moving target. Another generation of Linux uses
2568 glibc 2, which has chosen ip_opts for the structure name. This is now
2569 really a glibc thing rather than a Linux thing, so the condition name
2570 has been changed to reflect this. It is relevant also to GNU/Hurd.
2571
2572 Mac OS 10.x (Darwin) is like the later glibc versions, but without the
2573 setting of the __GLIBC__ macro, so we can't detect it automatically. There's
2574 a special macro defined in the os.h file.
2575
2576 Some DGUX versions on older hardware appear not to support IP options at
2577 all, so there is now a general macro which can be set to cut out this
2578 support altogether.
2579
2580 How to do this properly in IPv6 is not yet known. */
2581
2582 #if !HAVE_IPV6 && !defined(NO_IP_OPTIONS)
2583
2584 #ifdef GLIBC_IP_OPTIONS
2585 #if (!defined __GLIBC__) || (__GLIBC__ < 2)
2586 #define OPTSTYLE 1
2587 #else
2588 #define OPTSTYLE 2
2589 #endif
2590 #elif defined DARWIN_IP_OPTIONS
2591 #define OPTSTYLE 2
2592 #else
2593 #define OPTSTYLE 3
2594 #endif
2595
2596 if (!host_checking && !f.sender_host_notsocket)
2597 {
2598 #if OPTSTYLE == 1
2599 EXIM_SOCKLEN_T optlen = sizeof(struct ip_options) + MAX_IPOPTLEN;
2600 struct ip_options *ipopt = store_get(optlen);
2601 #elif OPTSTYLE == 2
2602 struct ip_opts ipoptblock;
2603 struct ip_opts *ipopt = &ipoptblock;
2604 EXIM_SOCKLEN_T optlen = sizeof(ipoptblock);
2605 #else
2606 struct ipoption ipoptblock;
2607 struct ipoption *ipopt = &ipoptblock;
2608 EXIM_SOCKLEN_T optlen = sizeof(ipoptblock);
2609 #endif
2610
2611 /* Occasional genuine failures of getsockopt() have been seen - for
2612 example, "reset by peer". Therefore, just log and give up on this
2613 call, unless the error is ENOPROTOOPT. This error is given by systems
2614 that have the interfaces but not the mechanism - e.g. GNU/Hurd at the time
2615 of writing. So for that error, carry on - we just can't do an IP options
2616 check. */
2617
2618 DEBUG(D_receive) debug_printf("checking for IP options\n");
2619
2620 if (getsockopt(fileno(smtp_out), IPPROTO_IP, IP_OPTIONS, US (ipopt),
2621 &optlen) < 0)
2622 {
2623 if (errno != ENOPROTOOPT)
2624 {
2625 log_write(0, LOG_MAIN, "getsockopt() failed from %s: %s",
2626 host_and_ident(FALSE), strerror(errno));
2627 smtp_printf("451 SMTP service not available\r\n", FALSE);
2628 return FALSE;
2629 }
2630 }
2631
2632 /* Deal with any IP options that are set. On the systems I have looked at,
2633 the value of MAX_IPOPTLEN has been 40, meaning that there should never be
2634 more logging data than will fit in big_buffer. Nevertheless, after somebody
2635 questioned this code, I've added in some paranoid checking. */
2636
2637 else if (optlen > 0)
2638 {
2639 uschar *p = big_buffer;
2640 uschar *pend = big_buffer + big_buffer_size;
2641 uschar *adptr;
2642 int optcount;
2643 struct in_addr addr;
2644
2645 #if OPTSTYLE == 1
2646 uschar *optstart = US (ipopt->__data);
2647 #elif OPTSTYLE == 2
2648 uschar *optstart = US (ipopt->ip_opts);
2649 #else
2650 uschar *optstart = US (ipopt->ipopt_list);
2651 #endif
2652
2653 DEBUG(D_receive) debug_printf("IP options exist\n");
2654
2655 Ustrcpy(p, "IP options on incoming call:");
2656 p += Ustrlen(p);
2657
2658 for (uschar * opt = optstart; opt && opt < US (ipopt) + optlen; )
2659 switch (*opt)
2660 {
2661 case IPOPT_EOL:
2662 opt = NULL;
2663 break;
2664
2665 case IPOPT_NOP:
2666 opt++;
2667 break;
2668
2669 case IPOPT_SSRR:
2670 case IPOPT_LSRR:
2671 if (!string_format(p, pend-p, " %s [@%s",
2672 (*opt == IPOPT_SSRR)? "SSRR" : "LSRR",
2673 #if OPTSTYLE == 1
2674 inet_ntoa(*((struct in_addr *)(&(ipopt->faddr))))))
2675 #elif OPTSTYLE == 2
2676 inet_ntoa(ipopt->ip_dst)))
2677 #else
2678 inet_ntoa(ipopt->ipopt_dst)))
2679 #endif
2680 {
2681 opt = NULL;
2682 break;
2683 }
2684
2685 p += Ustrlen(p);
2686 optcount = (opt[1] - 3) / sizeof(struct in_addr);
2687 adptr = opt + 3;
2688 while (optcount-- > 0)
2689 {
2690 memcpy(&addr, adptr, sizeof(addr));
2691 if (!string_format(p, pend - p - 1, "%s%s",
2692 (optcount == 0)? ":" : "@", inet_ntoa(addr)))
2693 {
2694 opt = NULL;
2695 break;
2696 }
2697 p += Ustrlen(p);
2698 adptr += sizeof(struct in_addr);
2699 }
2700 *p++ = ']';
2701 opt += opt[1];
2702 break;
2703
2704 default:
2705 {
2706 if (pend - p < 4 + 3*opt[1]) { opt = NULL; break; }
2707 Ustrcat(p, "[ ");
2708 p += 2;
2709 for (int i = 0; i < opt[1]; i++)
2710 p += sprintf(CS p, "%2.2x ", opt[i]);
2711 *p++ = ']';
2712 }
2713 opt += opt[1];
2714 break;
2715 }
2716
2717 *p = 0;
2718 log_write(0, LOG_MAIN, "%s", big_buffer);
2719
2720 /* Refuse any call with IP options. This is what tcpwrappers 7.5 does. */
2721
2722 log_write(0, LOG_MAIN|LOG_REJECT,
2723 "connection from %s refused (IP options)", host_and_ident(FALSE));
2724
2725 smtp_printf("554 SMTP service not available\r\n", FALSE);
2726 return FALSE;
2727 }
2728
2729 /* Length of options = 0 => there are no options */
2730
2731 else DEBUG(D_receive) debug_printf("no IP options found\n");
2732 }
2733 #endif /* HAVE_IPV6 && !defined(NO_IP_OPTIONS) */
2734
2735 /* Set keep-alive in socket options. The option is on by default. This
2736 setting is an attempt to get rid of some hanging connections that stick in
2737 read() when the remote end (usually a dialup) goes away. */
2738
2739 if (smtp_accept_keepalive && !f.sender_host_notsocket)
2740 ip_keepalive(fileno(smtp_out), sender_host_address, FALSE);
2741
2742 /* If the current host matches host_lookup, set the name by doing a
2743 reverse lookup. On failure, sender_host_name will be NULL and
2744 host_lookup_failed will be TRUE. This may or may not be serious - optional
2745 checks later. */
2746
2747 if (verify_check_host(&host_lookup) == OK)
2748 {
2749 (void)host_name_lookup();
2750 host_build_sender_fullhost();
2751 }
2752
2753 /* Delay this until we have the full name, if it is looked up. */
2754
2755 set_process_info("handling incoming connection from %s",
2756 host_and_ident(FALSE));
2757
2758 /* Expand smtp_receive_timeout, if needed */
2759
2760 if (smtp_receive_timeout_s)
2761 {
2762 uschar * exp;
2763 if ( !(exp = expand_string(smtp_receive_timeout_s))
2764 || !(*exp)
2765 || (smtp_receive_timeout = readconf_readtime(exp, 0, FALSE)) < 0
2766 )
2767 log_write(0, LOG_MAIN|LOG_PANIC,
2768 "bad value for smtp_receive_timeout: '%s'", exp ? exp : US"");
2769 }
2770
2771 /* Test for explicit connection rejection */
2772
2773 if (verify_check_host(&host_reject_connection) == OK)
2774 {
2775 log_write(L_connection_reject, LOG_MAIN|LOG_REJECT, "refused connection "
2776 "from %s (host_reject_connection)", host_and_ident(FALSE));
2777 smtp_printf("554 SMTP service not available\r\n", FALSE);
2778 return FALSE;
2779 }
2780
2781 /* Test with TCP Wrappers if so configured. There is a problem in that
2782 hosts_ctl() returns 0 (deny) under a number of system failure circumstances,
2783 such as disks dying. In these cases, it is desirable to reject with a 4xx
2784 error instead of a 5xx error. There isn't a "right" way to detect such
2785 problems. The following kludge is used: errno is zeroed before calling
2786 hosts_ctl(). If the result is "reject", a 5xx error is given only if the
2787 value of errno is 0 or ENOENT (which happens if /etc/hosts.{allow,deny} does
2788 not exist). */
2789
2790 #ifdef USE_TCP_WRAPPERS
2791 errno = 0;
2792 if (!(tcp_wrappers_name = expand_string(tcp_wrappers_daemon_name)))
2793 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "Expansion of \"%s\" "
2794 "(tcp_wrappers_name) failed: %s", string_printing(tcp_wrappers_name),
2795 expand_string_message);
2796
2797 if (!hosts_ctl(tcp_wrappers_name,
2798 sender_host_name ? CS sender_host_name : STRING_UNKNOWN,
2799 sender_host_address ? CS sender_host_address : STRING_UNKNOWN,
2800 sender_ident ? CS sender_ident : STRING_UNKNOWN))
2801 {
2802 if (errno == 0 || errno == ENOENT)
2803 {
2804 HDEBUG(D_receive) debug_printf("tcp wrappers rejection\n");
2805 log_write(L_connection_reject,
2806 LOG_MAIN|LOG_REJECT, "refused connection from %s "
2807 "(tcp wrappers)", host_and_ident(FALSE));
2808 smtp_printf("554 SMTP service not available\r\n", FALSE);
2809 }
2810 else
2811 {
2812 int save_errno = errno;
2813 HDEBUG(D_receive) debug_printf("tcp wrappers rejected with unexpected "
2814 "errno value %d\n", save_errno);
2815 log_write(L_connection_reject,
2816 LOG_MAIN|LOG_REJECT, "temporarily refused connection from %s "
2817 "(tcp wrappers errno=%d)", host_and_ident(FALSE), save_errno);
2818 smtp_printf("451 Temporary local problem - please try later\r\n", FALSE);
2819 }
2820 return FALSE;
2821 }
2822 #endif
2823
2824 /* Check for reserved slots. The value of smtp_accept_count has already been
2825 incremented to include this process. */
2826
2827 if (smtp_accept_max > 0 &&
2828 smtp_accept_count > smtp_accept_max - smtp_accept_reserve)
2829 {
2830 if ((rc = verify_check_host(&smtp_reserve_hosts)) != OK)
2831 {
2832 log_write(L_connection_reject,
2833 LOG_MAIN, "temporarily refused connection from %s: not in "
2834 "reserve list: connected=%d max=%d reserve=%d%s",
2835 host_and_ident(FALSE), smtp_accept_count - 1, smtp_accept_max,
2836 smtp_accept_reserve, (rc == DEFER)? " (lookup deferred)" : "");
2837 smtp_printf("421 %s: Too many concurrent SMTP connections; "
2838 "please try again later\r\n", FALSE, smtp_active_hostname);
2839 return FALSE;
2840 }
2841 reserved_host = TRUE;
2842 }
2843
2844 /* If a load level above which only messages from reserved hosts are
2845 accepted is set, check the load. For incoming calls via the daemon, the
2846 check is done in the superior process if there are no reserved hosts, to
2847 save a fork. In all cases, the load average will already be available
2848 in a global variable at this point. */
2849
2850 if (smtp_load_reserve >= 0 &&
2851 load_average > smtp_load_reserve &&
2852 !reserved_host &&
2853 verify_check_host(&smtp_reserve_hosts) != OK)
2854 {
2855 log_write(L_connection_reject,
2856 LOG_MAIN, "temporarily refused connection from %s: not in "
2857 "reserve list and load average = %.2f", host_and_ident(FALSE),
2858 (double)load_average/1000.0);
2859 smtp_printf("421 %s: Too much load; please try again later\r\n", FALSE,
2860 smtp_active_hostname);
2861 return FALSE;
2862 }
2863
2864 /* Determine whether unqualified senders or recipients are permitted
2865 for this host. Unfortunately, we have to do this every time, in order to
2866 set the flags so that they can be inspected when considering qualifying
2867 addresses in the headers. For a site that permits no qualification, this
2868 won't take long, however. */
2869
2870 f.allow_unqualified_sender =
2871 verify_check_host(&sender_unqualified_hosts) == OK;
2872
2873 f.allow_unqualified_recipient =
2874 verify_check_host(&recipient_unqualified_hosts) == OK;
2875
2876 /* Determine whether HELO/EHLO is required for this host. The requirement
2877 can be hard or soft. */
2878
2879 fl.helo_required = verify_check_host(&helo_verify_hosts) == OK;
2880 if (!fl.helo_required)
2881 fl.helo_verify = verify_check_host(&helo_try_verify_hosts) == OK;
2882
2883 /* Determine whether this hosts is permitted to send syntactic junk
2884 after a HELO or EHLO command. */
2885
2886 fl.helo_accept_junk = verify_check_host(&helo_accept_junk_hosts) == OK;
2887 }
2888
2889 /* For batch SMTP input we are now done. */
2890
2891 if (smtp_batched_input) return TRUE;
2892
2893 /* If valid Proxy Protocol source is connecting, set up session.
2894 * Failure will not allow any SMTP function other than QUIT. */
2895
2896 #ifdef SUPPORT_PROXY
2897 proxy_session = FALSE;
2898 f.proxy_session_failed = FALSE;
2899 if (check_proxy_protocol_host())
2900 setup_proxy_protocol_host();
2901 #endif
2902
2903 /* Start up TLS if tls_on_connect is set. This is for supporting the legacy
2904 smtps port for use with older style SSL MTAs. */
2905
2906 #ifdef SUPPORT_TLS
2907 if (tls_in.on_connect)
2908 {
2909 if (tls_server_start(tls_require_ciphers, &user_msg) != OK)
2910 return smtp_log_tls_fail(user_msg);
2911 cmd_list[CMD_LIST_TLS_AUTH].is_mail_cmd = TRUE;
2912 }
2913 #endif
2914
2915 /* Run the connect ACL if it exists */
2916
2917 user_msg = NULL;
2918 if (acl_smtp_connect)
2919 {
2920 int rc;
2921 if ((rc = acl_check(ACL_WHERE_CONNECT, NULL, acl_smtp_connect, &user_msg,
2922 &log_msg)) != OK)
2923 {
2924 (void) smtp_handle_acl_fail(ACL_WHERE_CONNECT, rc, user_msg, log_msg);
2925 return FALSE;
2926 }
2927 }
2928
2929 /* Output the initial message for a two-way SMTP connection. It may contain
2930 newlines, which then cause a multi-line response to be given. */
2931
2932 code = US"220"; /* Default status code */
2933 esc = US""; /* Default extended status code */
2934 esclen = 0; /* Length of esc */
2935
2936 if (!user_msg)
2937 {
2938 if (!(s = expand_string(smtp_banner)))
2939 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "Expansion of \"%s\" (smtp_banner) "
2940 "failed: %s", smtp_banner, expand_string_message);
2941 }
2942 else
2943 {
2944 int codelen = 3;
2945 s = user_msg;
2946 smtp_message_code(&code, &codelen, &s, NULL, TRUE);
2947 if (codelen > 4)
2948 {
2949 esc = code + 4;
2950 esclen = codelen - 4;
2951 }
2952 }
2953
2954 /* Remove any terminating newlines; might as well remove trailing space too */
2955
2956 p = s + Ustrlen(s);
2957 while (p > s && isspace(p[-1])) p--;
2958 *p = 0;
2959
2960 /* It seems that CC:Mail is braindead, and assumes that the greeting message
2961 is all contained in a single IP packet. The original code wrote out the
2962 greeting using several calls to fprint/fputc, and on busy servers this could
2963 cause it to be split over more than one packet - which caused CC:Mail to fall
2964 over when it got the second part of the greeting after sending its first
2965 command. Sigh. To try to avoid this, build the complete greeting message
2966 first, and output it in one fell swoop. This gives a better chance of it
2967 ending up as a single packet. */
2968
2969 ss = string_get(256);
2970
2971 p = s;
2972 do /* At least once, in case we have an empty string */
2973 {
2974 int len;
2975 uschar *linebreak = Ustrchr(p, '\n');
2976 ss = string_catn(ss, code, 3);
2977 if (!linebreak)
2978 {
2979 len = Ustrlen(p);
2980 ss = string_catn(ss, US" ", 1);
2981 }
2982 else
2983 {
2984 len = linebreak - p;
2985 ss = string_catn(ss, US"-", 1);
2986 }
2987 ss = string_catn(ss, esc, esclen);
2988 ss = string_catn(ss, p, len);
2989 ss = string_catn(ss, US"\r\n", 2);
2990 p += len;
2991 if (linebreak) p++;
2992 }
2993 while (*p);
2994
2995 /* Before we write the banner, check that there is no input pending, unless
2996 this synchronisation check is disabled. */
2997
2998 #ifdef EXPERIMENTAL_PIPE_CONNECT
2999 fl.pipe_connect_acceptable =
3000 sender_host_address && verify_check_host(&pipe_connect_advertise_hosts) == OK;
3001
3002 if (!check_sync())
3003 if (fl.pipe_connect_acceptable)
3004 f.smtp_in_early_pipe_used = TRUE;
3005 else
3006 #else
3007 if (!check_sync())
3008 #endif
3009 {
3010 unsigned n = smtp_inend - smtp_inptr;
3011 if (n > 32) n = 32;
3012
3013 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP protocol "
3014 "synchronization error (input sent without waiting for greeting): "
3015 "rejected connection from %s input=\"%s\"", host_and_ident(TRUE),
3016 string_printing(string_copyn(smtp_inptr, n)));
3017 smtp_printf("554 SMTP synchronization error\r\n", FALSE);
3018 return FALSE;
3019 }
3020
3021 /* Now output the banner */
3022 /*XXX the ehlo-resp code does its own tls/nontls bit. Maybe subroutine that? */
3023
3024 smtp_printf("%s",
3025 #ifdef EXPERIMENTAL_PIPE_CONNECT
3026 fl.pipe_connect_acceptable && pipeline_connect_sends(),
3027 #else
3028 FALSE,
3029 #endif
3030 string_from_gstring(ss));
3031
3032 /* Attempt to see if we sent the banner before the last ACK of the 3-way
3033 handshake arrived. If so we must have managed a TFO. */
3034
3035 #ifdef TCP_FASTOPEN
3036 tfo_in_check();
3037 #endif
3038
3039 return TRUE;
3040 }
3041
3042
3043
3044
3045
3046 /*************************************************
3047 * Handle SMTP syntax and protocol errors *
3048 *************************************************/
3049
3050 /* Write to the log for SMTP syntax errors in incoming commands, if configured
3051 to do so. Then transmit the error response. The return value depends on the
3052 number of syntax and protocol errors in this SMTP session.
3053
3054 Arguments:
3055 type error type, given as a log flag bit
3056 code response code; <= 0 means don't send a response
3057 data data to reflect in the response (can be NULL)
3058 errmess the error message
3059
3060 Returns: -1 limit of syntax/protocol errors NOT exceeded
3061 +1 limit of syntax/protocol errors IS exceeded
3062
3063 These values fit in with the values of the "done" variable in the main
3064 processing loop in smtp_setup_msg(). */
3065
3066 static int
3067 synprot_error(int type, int code, uschar *data, uschar *errmess)
3068 {
3069 int yield = -1;
3070
3071 log_write(type, LOG_MAIN, "SMTP %s error in \"%s\" %s %s",
3072 (type == L_smtp_syntax_error)? "syntax" : "protocol",
3073 string_printing(smtp_cmd_buffer), host_and_ident(TRUE), errmess);
3074
3075 if (++synprot_error_count > smtp_max_synprot_errors)
3076 {
3077 yield = 1;
3078 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
3079 "syntax or protocol errors (last command was \"%s\")",
3080 host_and_ident(FALSE), string_printing(smtp_cmd_buffer));
3081 }
3082
3083 if (code > 0)
3084 {
3085 smtp_printf("%d%c%s%s%s\r\n", FALSE, code, yield == 1 ? '-' : ' ',
3086 data ? data : US"", data ? US": " : US"", errmess);
3087 if (yield == 1)
3088 smtp_printf("%d Too many syntax or protocol errors\r\n", FALSE, code);
3089 }
3090
3091 return yield;
3092 }
3093
3094
3095
3096
3097 /*************************************************
3098 * Send SMTP response, possibly multiline *
3099 *************************************************/
3100
3101 /* There are, it seems, broken clients out there that cannot handle multiline
3102 responses. If no_multiline_responses is TRUE (it can be set from an ACL), we
3103 output nothing for non-final calls, and only the first line for anything else.
3104
3105 Arguments:
3106 code SMTP code, may involve extended status codes
3107 codelen length of smtp code; if > 4 there's an ESC
3108 final FALSE if the last line isn't the final line
3109 msg message text, possibly containing newlines
3110
3111 Returns: nothing
3112 */
3113
3114 void
3115 smtp_respond(uschar* code, int codelen, BOOL final, uschar *msg)
3116 {
3117 int esclen = 0;
3118 uschar *esc = US"";
3119
3120 if (!final && f.no_multiline_responses) return;
3121
3122 if (codelen > 4)
3123 {
3124 esc = code + 4;
3125 esclen = codelen - 4;
3126 }
3127
3128 /* If this is the first output for a (non-batch) RCPT command, see if all RCPTs
3129 have had the same. Note: this code is also present in smtp_printf(). It would
3130 be tidier to have it only in one place, but when it was added, it was easier to
3131 do it that way, so as not to have to mess with the code for the RCPT command,
3132 which sometimes uses smtp_printf() and sometimes smtp_respond(). */
3133
3134 if (fl.rcpt_in_progress)
3135 {
3136 if (rcpt_smtp_response == NULL)
3137 rcpt_smtp_response = string_copy(msg);
3138 else if (fl.rcpt_smtp_response_same &&
3139 Ustrcmp(rcpt_smtp_response, msg) != 0)
3140 fl.rcpt_smtp_response_same = FALSE;
3141 fl.rcpt_in_progress = FALSE;
3142 }
3143
3144 /* Now output the message, splitting it up into multiple lines if necessary.
3145 We only handle pipelining these responses as far as nonfinal/final groups,
3146 not the whole MAIL/RCPT/DATA response set. */
3147
3148 for (;;)
3149 {
3150 uschar *nl = Ustrchr(msg, '\n');
3151 if (nl == NULL)
3152 {
3153 smtp_printf("%.3s%c%.*s%s\r\n", !final, code, final ? ' ':'-', esclen, esc, msg);
3154 return;
3155 }
3156 else if (nl[1] == 0 || f.no_multiline_responses)
3157 {
3158 smtp_printf("%.3s%c%.*s%.*s\r\n", !final, code, final ? ' ':'-', esclen, esc,
3159 (int)(nl - msg), msg);
3160 return;
3161 }
3162 else
3163 {
3164 smtp_printf("%.3s-%.*s%.*s\r\n", TRUE, code, esclen, esc, (int)(nl - msg), msg);
3165 msg = nl + 1;
3166 while (isspace(*msg)) msg++;
3167 }
3168 }
3169 }
3170
3171
3172
3173
3174 /*************************************************
3175 * Parse user SMTP message *
3176 *************************************************/
3177
3178 /* This function allows for user messages overriding the response code details
3179 by providing a suitable response code string at the start of the message
3180 user_msg. Check the message for starting with a response code and optionally an
3181 extended status code. If found, check that the first digit is valid, and if so,
3182 change the code pointer and length to use the replacement. An invalid code
3183 causes a panic log; in this case, if the log messages is the same as the user
3184 message, we must also adjust the value of the log message to show the code that
3185 is actually going to be used (the original one).
3186
3187 This function is global because it is called from receive.c as well as within
3188 this module.
3189
3190 Note that the code length returned includes the terminating whitespace
3191 character, which is always included in the regex match.
3192
3193 Arguments:
3194 code SMTP code, may involve extended status codes
3195 codelen length of smtp code; if > 4 there's an ESC
3196 msg message text
3197 log_msg optional log message, to be adjusted with the new SMTP code
3198 check_valid if true, verify the response code
3199
3200 Returns: nothing
3201 */
3202
3203 void
3204 smtp_message_code(uschar **code, int *codelen, uschar **msg, uschar **log_msg,
3205 BOOL check_valid)
3206 {
3207 int n;
3208 int ovector[3];
3209
3210 if (!msg || !*msg) return;
3211
3212 if ((n = pcre_exec(regex_smtp_code, NULL, CS *msg, Ustrlen(*msg), 0,
3213 PCRE_EOPT, ovector, sizeof(ovector)/sizeof(int))) < 0) return;
3214
3215 if (check_valid && (*msg)[0] != (*code)[0])
3216 {
3217 log_write(0, LOG_MAIN|LOG_PANIC, "configured error code starts with "
3218 "incorrect digit (expected %c) in \"%s\"", (*code)[0], *msg);
3219 if (log_msg != NULL && *log_msg == *msg)
3220 *log_msg = string_sprintf("%s %s", *code, *log_msg + ovector[1]);
3221 }
3222 else
3223 {
3224 *code = *msg;
3225 *codelen = ovector[1]; /* Includes final space */
3226 }
3227 *msg += ovector[1]; /* Chop the code off the message */
3228 return;
3229 }
3230
3231
3232
3233
3234 /*************************************************
3235 * Handle an ACL failure *
3236 *************************************************/
3237
3238 /* This function is called when acl_check() fails. As well as calls from within
3239 this module, it is called from receive.c for an ACL after DATA. It sorts out
3240 logging the incident, and sends the error response. A message containing
3241 newlines is turned into a multiline SMTP response, but for logging, only the
3242 first line is used.
3243
3244 There's a table of default permanent failure response codes to use in
3245 globals.c, along with the table of names. VFRY is special. Despite RFC1123 it
3246 defaults disabled in Exim. However, discussion in connection with RFC 821bis
3247 (aka RFC 2821) has concluded that the response should be 252 in the disabled
3248 state, because there are broken clients that try VRFY before RCPT. A 5xx
3249 response should be given only when the address is positively known to be
3250 undeliverable. Sigh. We return 252 if there is no VRFY ACL or it provides
3251 no explicit code, but if there is one we let it know best.
3252 Also, for ETRN, 458 is given on refusal, and for AUTH, 503.
3253
3254 From Exim 4.63, it is possible to override the response code details by
3255 providing a suitable response code string at the start of the message provided
3256 in user_msg. The code's first digit is checked for validity.
3257
3258 Arguments:
3259 where where the ACL was called from
3260 rc the failure code
3261 user_msg a message that can be included in an SMTP response
3262 log_msg a message for logging
3263
3264 Returns: 0 in most cases
3265 2 if the failure code was FAIL_DROP, in which case the
3266 SMTP connection should be dropped (this value fits with the
3267 "done" variable in smtp_setup_msg() below)
3268 */
3269
3270 int
3271 smtp_handle_acl_fail(int where, int rc, uschar *user_msg, uschar *log_msg)
3272 {
3273 BOOL drop = rc == FAIL_DROP;
3274 int codelen = 3;
3275 uschar *smtp_code;
3276 uschar *lognl;
3277 uschar *sender_info = US"";
3278 uschar *what =
3279 #ifdef WITH_CONTENT_SCAN
3280 where == ACL_WHERE_MIME ? US"during MIME ACL checks" :
3281 #endif
3282 where == ACL_WHERE_PREDATA ? US"DATA" :
3283 where == ACL_WHERE_DATA ? US"after DATA" :
3284 #ifndef DISABLE_PRDR
3285 where == ACL_WHERE_PRDR ? US"after DATA PRDR" :
3286 #endif
3287 smtp_cmd_data ?
3288 string_sprintf("%s %s", acl_wherenames[where], smtp_cmd_data) :
3289 string_sprintf("%s in \"connect\" ACL", acl_wherenames[where]);
3290
3291 if (drop) rc = FAIL;
3292
3293 /* Set the default SMTP code, and allow a user message to change it. */
3294
3295 smtp_code = rc == FAIL ? acl_wherecodes[where] : US"451";
3296 smtp_message_code(&smtp_code, &codelen, &user_msg, &log_msg,
3297 where != ACL_WHERE_VRFY);
3298
3299 /* We used to have sender_address here; however, there was a bug that was not
3300 updating sender_address after a rewrite during a verify. When this bug was
3301 fixed, sender_address at this point became the rewritten address. I'm not sure
3302 this is what should be logged, so I've changed to logging the unrewritten
3303 address to retain backward compatibility. */
3304
3305 #ifndef WITH_CONTENT_SCAN
3306 if (where == ACL_WHERE_RCPT || where == ACL_WHERE_DATA)
3307 #else
3308 if (where == ACL_WHERE_RCPT || where == ACL_WHERE_DATA || where == ACL_WHERE_MIME)
3309 #endif
3310 {
3311 sender_info = string_sprintf("F=<%s>%s%s%s%s ",
3312 sender_address_unrewritten ? sender_address_unrewritten : sender_address,
3313 sender_host_authenticated ? US" A=" : US"",
3314 sender_host_authenticated ? sender_host_authenticated : US"",
3315 sender_host_authenticated && authenticated_id ? US":" : US"",
3316 sender_host_authenticated && authenticated_id ? authenticated_id : US""
3317 );
3318 }
3319
3320 /* If there's been a sender verification failure with a specific message, and
3321 we have not sent a response about it yet, do so now, as a preliminary line for
3322 failures, but not defers. However, always log it for defer, and log it for fail
3323 unless the sender_verify_fail log selector has been turned off. */
3324
3325 if (sender_verified_failed &&
3326 !testflag(sender_verified_failed, af_sverify_told))
3327 {
3328 BOOL save_rcpt_in_progress = fl.rcpt_in_progress;
3329 fl.rcpt_in_progress = FALSE; /* So as not to treat these as the error */
3330
3331 setflag(sender_verified_failed, af_sverify_told);
3332
3333 if (rc != FAIL || LOGGING(sender_verify_fail))
3334 log_write(0, LOG_MAIN|LOG_REJECT, "%s sender verify %s for <%s>%s",
3335 host_and_ident(TRUE),
3336 ((sender_verified_failed->special_action & 255) == DEFER)? "defer":"fail",
3337 sender_verified_failed->address,
3338 (sender_verified_failed->message == NULL)? US"" :
3339 string_sprintf(": %s", sender_verified_failed->message));
3340
3341 if (rc == FAIL && sender_verified_failed->user_message)
3342 smtp_respond(smtp_code, codelen, FALSE, string_sprintf(
3343 testflag(sender_verified_failed, af_verify_pmfail)?
3344 "Postmaster verification failed while checking <%s>\n%s\n"
3345 "Several RFCs state that you are required to have a postmaster\n"
3346 "mailbox for each mail domain. This host does not accept mail\n"
3347 "from domains whose servers reject the postmaster address."
3348 :
3349 testflag(sender_verified_failed, af_verify_nsfail)?
3350 "Callback setup failed while verifying <%s>\n%s\n"
3351 "The initial connection, or a HELO or MAIL FROM:<> command was\n"
3352 "rejected. Refusing MAIL FROM:<> does not help fight spam, disregards\n"
3353 "RFC requirements, and stops you from receiving standard bounce\n"
3354 "messages. This host does not accept mail from domains whose servers\n"
3355 "refuse bounces."
3356 :
3357 "Verification failed for <%s>\n%s",
3358 sender_verified_failed->address,
3359 sender_verified_failed->user_message));
3360
3361 fl.rcpt_in_progress = save_rcpt_in_progress;
3362 }
3363
3364 /* Sort out text for logging */
3365
3366 log_msg = log_msg ? string_sprintf(": %s", log_msg) : US"";
3367 if ((lognl = Ustrchr(log_msg, '\n'))) *lognl = 0;
3368
3369 /* Send permanent failure response to the command, but the code used isn't
3370 always a 5xx one - see comments at the start of this function. If the original
3371 rc was FAIL_DROP we drop the connection and yield 2. */
3372
3373 if (rc == FAIL)
3374 smtp_respond(smtp_code, codelen, TRUE,
3375 user_msg ? user_msg : US"Administrative prohibition");
3376
3377 /* Send temporary failure response to the command. Don't give any details,
3378 unless acl_temp_details is set. This is TRUE for a callout defer, a "defer"
3379 verb, and for a header verify when smtp_return_error_details is set.
3380
3381 This conditional logic is all somewhat of a mess because of the odd
3382 interactions between temp_details and return_error_details. One day it should
3383 be re-implemented in a tidier fashion. */
3384
3385 else
3386 if (f.acl_temp_details && user_msg)
3387 {
3388 if ( smtp_return_error_details
3389 && sender_verified_failed
3390 && sender_verified_failed->message
3391 )
3392 smtp_respond(smtp_code, codelen, FALSE, sender_verified_failed->message);
3393
3394 smtp_respond(smtp_code, codelen, TRUE, user_msg);
3395 }
3396 else
3397 smtp_respond(smtp_code, codelen, TRUE,
3398 US"Temporary local problem - please try later");
3399
3400 /* Log the incident to the logs that are specified by log_reject_target
3401 (default main, reject). This can be empty to suppress logging of rejections. If
3402 the connection is not forcibly to be dropped, return 0. Otherwise, log why it
3403 is closing if required and return 2. */
3404
3405 if (log_reject_target != 0)
3406 {
3407 #ifdef SUPPORT_TLS
3408 gstring * g = s_tlslog(NULL);
3409 uschar * tls = string_from_gstring(g);
3410 if (!tls) tls = US"";
3411 #else
3412 uschar * tls = US"";
3413 #endif
3414 log_write(where == ACL_WHERE_CONNECT ? L_connection_reject : 0,
3415 log_reject_target, "%s%s%s %s%srejected %s%s",
3416 LOGGING(dnssec) && sender_host_dnssec ? US" DS" : US"",
3417 host_and_ident(TRUE),
3418 tls,
3419 sender_info,
3420 rc == FAIL ? US"" : US"temporarily ",
3421 what, log_msg);
3422 }
3423
3424 if (!drop) return 0;
3425
3426 log_write(L_smtp_connection, LOG_MAIN, "%s closed by DROP in ACL",
3427 smtp_get_connection_info());
3428
3429 /* Run the not-quit ACL, but without any custom messages. This should not be a
3430 problem, because we get here only if some other ACL has issued "drop", and
3431 in that case, *its* custom messages will have been used above. */
3432
3433 smtp_notquit_exit(US"acl-drop", NULL, NULL);
3434 return 2;
3435 }
3436
3437
3438
3439
3440 /*************************************************
3441 * Handle SMTP exit when QUIT is not given *
3442 *************************************************/
3443
3444 /* This function provides a logging/statistics hook for when an SMTP connection
3445 is dropped on the floor or the other end goes away. It's a global function
3446 because it's called from receive.c as well as this module. As well as running
3447 the NOTQUIT ACL, if there is one, this function also outputs a final SMTP
3448 response, either with a custom message from the ACL, or using a default. There
3449 is one case, however, when no message is output - after "drop". In that case,
3450 the ACL that obeyed "drop" has already supplied the custom message, and NULL is
3451 passed to this function.
3452
3453 In case things go wrong while processing this function, causing an error that
3454 may re-enter this function, there is a recursion check.
3455
3456 Arguments:
3457 reason What $smtp_notquit_reason will be set to in the ACL;
3458 if NULL, the ACL is not run
3459 code The error code to return as part of the response
3460 defaultrespond The default message if there's no user_msg
3461
3462 Returns: Nothing
3463 */
3464
3465 void
3466 smtp_notquit_exit(uschar *reason, uschar *code, uschar *defaultrespond, ...)
3467 {
3468 int rc;
3469 uschar *user_msg = NULL;
3470 uschar *log_msg = NULL;
3471
3472 /* Check for recursive call */
3473
3474 if (fl.smtp_exit_function_called)
3475 {
3476 log_write(0, LOG_PANIC, "smtp_notquit_exit() called more than once (%s)",
3477 reason);
3478 return;
3479 }
3480 fl.smtp_exit_function_called = TRUE;
3481
3482 /* Call the not-QUIT ACL, if there is one, unless no reason is given. */
3483
3484 if (acl_smtp_notquit && reason)
3485 {
3486 smtp_notquit_reason = reason;
3487 if ((rc = acl_check(ACL_WHERE_NOTQUIT, NULL, acl_smtp_notquit, &user_msg,
3488 &log_msg)) == ERROR)
3489 log_write(0, LOG_MAIN|LOG_PANIC, "ACL for not-QUIT returned ERROR: %s",
3490 log_msg);
3491 }
3492
3493 /* If the connection was dropped, we certainly are no longer talking TLS */
3494 tls_in.active.sock = -1;
3495
3496 /* Write an SMTP response if we are expected to give one. As the default
3497 responses are all internal, they should be reasonable size. */
3498
3499 if (code && defaultrespond)
3500 {
3501 if (user_msg)
3502 smtp_respond(code, 3, TRUE, user_msg);
3503 else
3504 {
3505 gstring * g;
3506 va_list ap;
3507
3508 va_start(ap, defaultrespond);
3509 g = string_vformat(NULL, TRUE, CS defaultrespond, ap);
3510 va_end(ap);
3511 smtp_printf("%s %s\r\n", FALSE, code, string_from_gstring(g));
3512 }
3513 mac_smtp_fflush();
3514 }
3515 }
3516
3517
3518
3519
3520 /*************************************************
3521 * Verify HELO argument *
3522 *************************************************/
3523
3524 /* This function is called if helo_verify_hosts or helo_try_verify_hosts is
3525 matched. It is also called from ACL processing if verify = helo is used and
3526 verification was not previously tried (i.e. helo_try_verify_hosts was not
3527 matched). The result of its processing is to set helo_verified and
3528 helo_verify_failed. These variables should both be FALSE for this function to
3529 be called.
3530
3531 Note that EHLO/HELO is legitimately allowed to quote an address literal. Allow
3532 for IPv6 ::ffff: literals.
3533
3534 Argument: none
3535 Returns: TRUE if testing was completed;
3536 FALSE on a temporary failure
3537 */
3538
3539 BOOL
3540 smtp_verify_helo(void)
3541 {
3542 BOOL yield = TRUE;
3543
3544 HDEBUG(D_receive) debug_printf("verifying EHLO/HELO argument \"%s\"\n",
3545 sender_helo_name);
3546
3547 if (sender_helo_name == NULL)
3548 {
3549 HDEBUG(D_receive) debug_printf("no EHLO/HELO command was issued\n");
3550 }
3551
3552 /* Deal with the case of -bs without an IP address */
3553
3554 else if (sender_host_address == NULL)
3555 {
3556 HDEBUG(D_receive) debug_printf("no client IP address: assume success\n");
3557 f.helo_verified = TRUE;
3558 }
3559
3560 /* Deal with the more common case when there is a sending IP address */
3561
3562 else if (sender_helo_name[0] == '[')
3563 {
3564 f.helo_verified = Ustrncmp(sender_helo_name+1, sender_host_address,
3565 Ustrlen(sender_host_address)) == 0;
3566
3567 #if HAVE_IPV6
3568 if (!f.helo_verified)
3569 {
3570 if (strncmpic(sender_host_address, US"::ffff:", 7) == 0)
3571 f.helo_verified = Ustrncmp(sender_helo_name + 1,
3572 sender_host_address + 7, Ustrlen(sender_host_address) - 7) == 0;
3573 }
3574 #endif
3575
3576 HDEBUG(D_receive)
3577 { if (f.helo_verified) debug_printf("matched host address\n"); }
3578 }
3579
3580 /* Do a reverse lookup if one hasn't already given a positive or negative
3581 response. If that fails, or the name doesn't match, try checking with a forward
3582 lookup. */
3583
3584 else
3585 {
3586 if (sender_host_name == NULL && !host_lookup_failed)
3587 yield = host_name_lookup() != DEFER;
3588
3589 /* If a host name is known, check it and all its aliases. */
3590
3591 if (sender_host_name)
3592 if ((f.helo_verified = strcmpic(sender_host_name, sender_helo_name) == 0))
3593 {
3594 sender_helo_dnssec = sender_host_dnssec;
3595 HDEBUG(D_receive) debug_printf("matched host name\n");
3596 }
3597 else
3598 {
3599 uschar **aliases = sender_host_aliases;
3600 while (*aliases)
3601 if ((f.helo_verified = strcmpic(*aliases++, sender_helo_name) == 0))
3602 {
3603 sender_helo_dnssec = sender_host_dnssec;
3604 break;
3605 }
3606
3607 HDEBUG(D_receive) if (f.helo_verified)
3608 debug_printf("matched alias %s\n", *(--aliases));
3609 }
3610
3611 /* Final attempt: try a forward lookup of the helo name */
3612
3613 if (!f.helo_verified)
3614 {
3615 int rc;
3616 host_item h =
3617 {.name = sender_helo_name, .address = NULL, .mx = MX_NONE, .next = NULL};
3618 dnssec_domains d =
3619 {.request = US"*", .require = US""};
3620
3621 HDEBUG(D_receive) debug_printf("getting IP address for %s\n",
3622 sender_helo_name);
3623 rc = host_find_bydns(&h, NULL, HOST_FIND_BY_A | HOST_FIND_BY_AAAA,
3624 NULL, NULL, NULL, &d, NULL, NULL);
3625 if (rc == HOST_FOUND || rc == HOST_FOUND_LOCAL)
3626 for (host_item * hh = &h; hh; hh = hh->next)
3627 if (Ustrcmp(hh->address, sender_host_address) == 0)
3628 {
3629 f.helo_verified = TRUE;
3630 if (h.dnssec == DS_YES) sender_helo_dnssec = TRUE;
3631 HDEBUG(D_receive)
3632 debug_printf("IP address for %s matches calling address\n"
3633 "Forward DNS security status: %sverified\n",
3634 sender_helo_name, sender_helo_dnssec ? "" : "un");
3635 break;
3636 }
3637 }
3638 }
3639
3640 if (!f.helo_verified) f.helo_verify_failed = TRUE; /* We've tried ... */
3641 return yield;
3642 }
3643
3644
3645
3646
3647 /*************************************************
3648 * Send user response message *
3649 *************************************************/
3650
3651 /* This function is passed a default response code and a user message. It calls
3652 smtp_message_code() to check and possibly modify the response code, and then
3653 calls smtp_respond() to transmit the response. I put this into a function
3654 just to avoid a lot of repetition.
3655
3656 Arguments:
3657 code the response code
3658 user_msg the user message
3659
3660 Returns: nothing
3661 */
3662
3663 static void
3664 smtp_user_msg(uschar *code, uschar *user_msg)
3665 {
3666 int len = 3;
3667 smtp_message_code(&code, &len, &user_msg, NULL, TRUE);
3668 smtp_respond(code, len, TRUE, user_msg);
3669 }
3670
3671
3672
3673 static int
3674 smtp_in_auth(auth_instance *au, uschar ** s, uschar ** ss)
3675 {
3676 const uschar *set_id = NULL;
3677 int rc;
3678
3679 /* Run the checking code, passing the remainder of the command line as
3680 data. Initials the $auth<n> variables as empty. Initialize $0 empty and set
3681 it as the only set numerical variable. The authenticator may set $auth<n>
3682 and also set other numeric variables. The $auth<n> variables are preferred
3683 nowadays; the numerical variables remain for backwards compatibility.
3684
3685 Afterwards, have a go at expanding the set_id string, even if
3686 authentication failed - for bad passwords it can be useful to log the
3687 userid. On success, require set_id to expand and exist, and put it in
3688 authenticated_id. Save this in permanent store, as the working store gets
3689 reset at HELO, RSET, etc. */
3690
3691 for (int i = 0; i < AUTH_VARS; i++) auth_vars[i] = NULL;
3692 expand_nmax = 0;
3693 expand_nlength[0] = 0; /* $0 contains nothing */
3694
3695 rc = (au->info->servercode)(au, smtp_cmd_data);
3696 if (au->set_id) set_id = expand_string(au->set_id);
3697 expand_nmax = -1; /* Reset numeric variables */
3698 for (int i = 0; i < AUTH_VARS; i++) auth_vars[i] = NULL; /* Reset $auth<n> */
3699
3700 /* The value of authenticated_id is stored in the spool file and printed in
3701 log lines. It must not contain binary zeros or newline characters. In
3702 normal use, it never will, but when playing around or testing, this error
3703 can (did) happen. To guard against this, ensure that the id contains only
3704 printing characters. */
3705
3706 if (set_id) set_id = string_printing(set_id);
3707
3708 /* For the non-OK cases, set up additional logging data if set_id
3709 is not empty. */
3710
3711 if (rc != OK)
3712 set_id = set_id && *set_id
3713 ? string_sprintf(" (set_id=%s)", set_id) : US"";
3714
3715 /* Switch on the result */
3716
3717 switch(rc)
3718 {
3719 case OK:
3720 if (!au->set_id || set_id) /* Complete success */
3721 {
3722 if (set_id) authenticated_id = string_copy_malloc(set_id);
3723 sender_host_authenticated = au->name;
3724 sender_host_auth_pubname = au->public_name;
3725 authentication_failed = FALSE;
3726 authenticated_fail_id = NULL; /* Impossible to already be set? */
3727
3728 received_protocol =
3729 (sender_host_address ? protocols : protocols_local)
3730 [pextend + pauthed + (tls_in.active.sock >= 0 ? pcrpted:0)];
3731 *s = *ss = US"235 Authentication succeeded";
3732 authenticated_by = au;
3733 break;
3734 }
3735
3736 /* Authentication succeeded, but we failed to expand the set_id string.
3737 Treat this as a temporary error. */
3738
3739 auth_defer_msg = expand_string_message;
3740 /* Fall through */
3741
3742 case DEFER:
3743 if (set_id) authenticated_fail_id = string_copy_malloc(set_id);
3744 *s = string_sprintf("435 Unable to authenticate at present%s",
3745 auth_defer_user_msg);
3746 *ss = string_sprintf("435 Unable to authenticate at present%s: %s",
3747 set_id, auth_defer_msg);
3748 break;
3749
3750 case BAD64:
3751 *s = *ss = US"501 Invalid base64 data";
3752 break;
3753
3754 case CANCELLED:
3755 *s = *ss = US"501 Authentication cancelled";
3756 break;
3757
3758 case UNEXPECTED:
3759 *s = *ss = US"553 Initial data not expected";
3760 break;
3761
3762 case FAIL:
3763 if (set_id) authenticated_fail_id = string_copy_malloc(set_id);
3764 *s = US"535 Incorrect authentication data";
3765 *ss = string_sprintf("535 Incorrect authentication data%s", set_id);
3766 break;
3767
3768 default:
3769 if (set_id) authenticated_fail_id = string_copy_malloc(set_id);
3770 *s = US"435 Internal error";
3771 *ss = string_sprintf("435 Internal error%s: return %d from authentication "
3772 "check", set_id, rc);
3773 break;
3774 }
3775
3776 return rc;
3777 }
3778
3779
3780
3781
3782
3783 static int
3784 qualify_recipient(uschar ** recipient, uschar * smtp_cmd_data, uschar * tag)
3785 {
3786 int rd;
3787 if (f.allow_unqualified_recipient || strcmpic(*recipient, US"postmaster") == 0)
3788 {
3789 DEBUG(D_receive) debug_printf("unqualified address %s accepted\n",
3790 *recipient);
3791 rd = Ustrlen(recipient) + 1;
3792 *recipient = rewrite_address_qualify(*recipient, TRUE);
3793 return rd;
3794 }
3795 smtp_printf("501 %s: recipient address must contain a domain\r\n", FALSE,
3796 smtp_cmd_data);
3797 log_write(L_smtp_syntax_error,
3798 LOG_MAIN|LOG_REJECT, "unqualified %s rejected: <%s> %s%s",
3799 tag, *recipient, host_and_ident(TRUE), host_lookup_msg);
3800 return 0;
3801 }
3802
3803
3804
3805
3806 static void
3807 smtp_quit_handler(uschar ** user_msgp, uschar ** log_msgp)
3808 {
3809 HAD(SCH_QUIT);
3810 incomplete_transaction_log(US"QUIT");
3811 if (acl_smtp_quit)
3812 {
3813 int rc = acl_check(ACL_WHERE_QUIT, NULL, acl_smtp_quit, user_msgp, log_msgp);
3814 if (rc == ERROR)
3815 log_write(0, LOG_MAIN|LOG_PANIC, "ACL for QUIT returned ERROR: %s",
3816 *log_msgp);
3817 }
3818
3819 #ifdef TCP_CORK
3820 (void) setsockopt(fileno(smtp_out), IPPROTO_TCP, TCP_CORK, US &on, sizeof(on));
3821 #endif
3822
3823 if (*user_msgp)
3824 smtp_respond(US"221", 3, TRUE, *user_msgp);
3825 else
3826 smtp_printf("221 %s closing connection\r\n", FALSE, smtp_active_hostname);
3827
3828 #ifdef SUPPORT_TLS
3829 tls_close(NULL, TLS_SHUTDOWN_NOWAIT);
3830 #endif
3831
3832 log_write(L_smtp_connection, LOG_MAIN, "%s closed by QUIT",
3833 smtp_get_connection_info());
3834 }
3835
3836
3837 static void
3838 smtp_rset_handler(void)
3839 {
3840 HAD(SCH_RSET);
3841 incomplete_transaction_log(US"RSET");
3842 smtp_printf("250 Reset OK\r\n", FALSE);
3843 cmd_list[CMD_LIST_RSET].is_mail_cmd = FALSE;
3844 }
3845
3846
3847
3848 /*************************************************
3849 * Initialize for SMTP incoming message *
3850 *************************************************/
3851
3852 /* This function conducts the initial dialogue at the start of an incoming SMTP
3853 message, and builds a list of recipients. However, if the incoming message
3854 is part of a batch (-bS option) a separate function is called since it would
3855 be messy having tests splattered about all over this function. This function
3856 therefore handles the case where interaction is occurring. The input and output
3857 files are set up in smtp_in and smtp_out.
3858
3859 The global recipients_list is set to point to a vector of recipient_item
3860 blocks, whose number is given by recipients_count. This is extended by the
3861 receive_add_recipient() function. The global variable sender_address is set to
3862 the sender's address. The yield is +1 if a message has been successfully
3863 started, 0 if a QUIT command was encountered or the connection was refused from
3864 the particular host, or -1 if the connection was lost.
3865
3866 Argument: none
3867
3868 Returns: > 0 message successfully started (reached DATA)
3869 = 0 QUIT read or end of file reached or call refused
3870 < 0 lost connection
3871 */
3872
3873 int
3874 smtp_setup_msg(void)
3875 {
3876 int done = 0;
3877 BOOL toomany = FALSE;
3878 BOOL discarded = FALSE;
3879 BOOL last_was_rej_mail = FALSE;
3880 BOOL last_was_rcpt = FALSE;
3881 void *reset_point = store_get(0);
3882
3883 DEBUG(D_receive) debug_printf("smtp_setup_msg entered\n");
3884
3885 /* Reset for start of new message. We allow one RSET not to be counted as a
3886 nonmail command, for those MTAs that insist on sending it between every
3887 message. Ditto for EHLO/HELO and for STARTTLS, to allow for going in and out of
3888 TLS between messages (an Exim client may do this if it has messages queued up
3889 for the host). Note: we do NOT reset AUTH at this point. */
3890
3891 smtp_reset(reset_point);
3892 message_ended = END_NOTSTARTED;
3893
3894 chunking_state = f.chunking_offered ? CHUNKING_OFFERED : CHUNKING_NOT_OFFERED;
3895
3896 cmd_list[CMD_LIST_RSET].is_mail_cmd = TRUE;
3897 cmd_list[CMD_LIST_HELO].is_mail_cmd = TRUE;
3898 cmd_list[CMD_LIST_EHLO].is_mail_cmd = TRUE;
3899 #ifdef SUPPORT_TLS
3900 cmd_list[CMD_LIST_STARTTLS].is_mail_cmd = TRUE;
3901 #endif
3902
3903 /* Set the local signal handler for SIGTERM - it tries to end off tidily */
3904
3905 had_command_sigterm = 0;
3906 os_non_restarting_signal(SIGTERM, command_sigterm_handler);
3907
3908 /* Batched SMTP is handled in a different function. */
3909
3910 if (smtp_batched_input) return smtp_setup_batch_msg();
3911
3912 /* Deal with SMTP commands. This loop is exited by setting done to a POSITIVE
3913 value. The values are 2 larger than the required yield of the function. */
3914
3915 while (done <= 0)
3916 {
3917 const uschar **argv;
3918 uschar *etrn_command;
3919 uschar *etrn_serialize_key;
3920 uschar *errmess;
3921 uschar *log_msg, *smtp_code;
3922 uschar *user_msg = NULL;
3923 uschar *recipient = NULL;
3924 uschar *hello = NULL;
3925 uschar *s, *ss;
3926 BOOL was_rej_mail = FALSE;
3927 BOOL was_rcpt = FALSE;
3928 void (*oldsignal)(int);
3929 pid_t pid;
3930 int start, end, sender_domain, recipient_domain;
3931 int rc;
3932 int c;
3933 uschar *orcpt = NULL;
3934 int dsn_flags;
3935 gstring * g;
3936
3937 #ifdef AUTH_TLS
3938 /* Check once per STARTTLS or SSL-on-connect for a TLS AUTH */
3939 if ( tls_in.active.sock >= 0
3940 && tls_in.peercert
3941 && tls_in.certificate_verified
3942 && cmd_list[CMD_LIST_TLS_AUTH].is_mail_cmd
3943 )
3944 {
3945 cmd_list[CMD_LIST_TLS_AUTH].is_mail_cmd = FALSE;
3946
3947 for (auth_instance * au = auths; au; au = au->next)
3948 if (strcmpic(US"tls", au->driver_name) == 0)
3949 {
3950 if ( acl_smtp_auth
3951 && (rc = acl_check(ACL_WHERE_AUTH, NULL, acl_smtp_auth,
3952 &user_msg, &log_msg)) != OK
3953 )
3954 done = smtp_handle_acl_fail(ACL_WHERE_AUTH, rc, user_msg, log_msg);
3955 else
3956 {
3957 smtp_cmd_data = NULL;
3958
3959 if (smtp_in_auth(au, &s, &ss) == OK)
3960 { DEBUG(D_auth) debug_printf("tls auth succeeded\n"); }
3961 else
3962 { DEBUG(D_auth) debug_printf("tls auth not succeeded\n"); }
3963 }
3964 break;
3965 }
3966 }
3967 #endif
3968
3969 #ifdef TCP_QUICKACK
3970 if (smtp_in) /* Avoid pure-ACKs while in cmd pingpong phase */
3971 (void) setsockopt(fileno(smtp_in), IPPROTO_TCP, TCP_QUICKACK,
3972 US &off, sizeof(off));
3973 #endif
3974
3975 switch(smtp_read_command(
3976 #ifdef EXPERIMENTAL_PIPE_CONNECT
3977 !fl.pipe_connect_acceptable,
3978 #else
3979 TRUE,
3980 #endif
3981 GETC_BUFFER_UNLIMITED))
3982 {
3983 /* The AUTH command is not permitted to occur inside a transaction, and may
3984 occur successfully only once per connection. Actually, that isn't quite
3985 true. When TLS is started, all previous information about a connection must
3986 be discarded, so a new AUTH is permitted at that time.
3987
3988 AUTH may only be used when it has been advertised. However, it seems that
3989 there are clients that send AUTH when it hasn't been advertised, some of
3990 them even doing this after HELO. And there are MTAs that accept this. Sigh.
3991 So there's a get-out that allows this to happen.
3992
3993 AUTH is initially labelled as a "nonmail command" so that one occurrence
3994 doesn't get counted. We change the label here so that multiple failing
3995 AUTHS will eventually hit the nonmail threshold. */
3996
3997 case AUTH_CMD:
3998 HAD(SCH_AUTH);
3999 authentication_failed = TRUE;
4000 cmd_list[CMD_LIST_AUTH].is_mail_cmd = FALSE;
4001
4002 if (!fl.auth_advertised && !f.allow_auth_unadvertised)
4003 {
4004 done = synprot_error(L_smtp_protocol_error, 503, NULL,
4005 US"AUTH command used when not advertised");
4006 break;
4007 }
4008 if (sender_host_authenticated)
4009 {
4010 done = synprot_error(L_smtp_protocol_error, 503, NULL,
4011 US"already authenticated");
4012 break;
4013 }
4014 if (sender_address)
4015 {
4016 done = synprot_error(L_smtp_protocol_error, 503, NULL,
4017 US"not permitted in mail transaction");
4018 break;
4019 }
4020
4021 /* Check the ACL */
4022
4023 if ( acl_smtp_auth
4024 && (rc = acl_check(ACL_WHERE_AUTH, NULL, acl_smtp_auth,
4025 &user_msg, &log_msg)) != OK
4026 )
4027 {
4028 done = smtp_handle_acl_fail(ACL_WHERE_AUTH, rc, user_msg, log_msg);
4029 break;
4030 }
4031
4032 /* Find the name of the requested authentication mechanism. */
4033
4034 s = smtp_cmd_data;
4035 while ((c = *smtp_cmd_data) != 0 && !isspace(c))
4036 {
4037 if (!isalnum(c) && c != '-' && c != '_')
4038 {
4039 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4040 US"invalid character in authentication mechanism name");
4041 goto COMMAND_LOOP;
4042 }
4043 smtp_cmd_data++;
4044 }
4045
4046 /* If not at the end of the line, we must be at white space. Terminate the
4047 name and move the pointer on to any data that may be present. */
4048
4049 if (*smtp_cmd_data != 0)
4050 {
4051 *smtp_cmd_data++ = 0;
4052 while (isspace(*smtp_cmd_data)) smtp_cmd_data++;
4053 }
4054
4055 /* Search for an authentication mechanism which is configured for use
4056 as a server and which has been advertised (unless, sigh, allow_auth_
4057 unadvertised is set). */
4058
4059 {
4060 auth_instance * au;
4061 for (au = auths; au; au = au->next)
4062 if (strcmpic(s, au->public_name) == 0 && au->server &&
4063 (au->advertised || f.allow_auth_unadvertised))
4064 break;
4065
4066 if (au)
4067 {
4068 c = smtp_in_auth(au, &s, &ss);
4069
4070 smtp_printf("%s\r\n", FALSE, s);
4071 if (c != OK)
4072 log_write(0, LOG_MAIN|LOG_REJECT, "%s authenticator failed for %s: %s",
4073 au->name, host_and_ident(FALSE), ss);
4074 }
4075 else
4076 done = synprot_error(L_smtp_protocol_error, 504, NULL,
4077 string_sprintf("%s authentication mechanism not supported", s));
4078 }
4079
4080 break; /* AUTH_CMD */
4081
4082 /* The HELO/EHLO commands are permitted to appear in the middle of a
4083 session as well as at the beginning. They have the effect of a reset in
4084 addition to their other functions. Their absence at the start cannot be
4085 taken to be an error.
4086
4087 RFC 2821 says:
4088
4089 If the EHLO command is not acceptable to the SMTP server, 501, 500,
4090 or 502 failure replies MUST be returned as appropriate. The SMTP
4091 server MUST stay in the same state after transmitting these replies
4092 that it was in before the EHLO was received.
4093
4094 Therefore, we do not do the reset until after checking the command for
4095 acceptability. This change was made for Exim release 4.11. Previously
4096 it did the reset first. */
4097
4098 case HELO_CMD:
4099 HAD(SCH_HELO);
4100 hello = US"HELO";
4101 fl.esmtp = FALSE;
4102 goto HELO_EHLO;
4103
4104 case EHLO_CMD:
4105 HAD(SCH_EHLO);
4106 hello = US"EHLO";
4107 fl.esmtp = TRUE;
4108
4109 HELO_EHLO: /* Common code for HELO and EHLO */
4110 cmd_list[CMD_LIST_HELO].is_mail_cmd = FALSE;
4111 cmd_list[CMD_LIST_EHLO].is_mail_cmd = FALSE;