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