00c842760525b1e49632ab71bc5c78071132d1de
[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 BOOL rcpt_smtp_response_same :1;
149 BOOL rcpt_in_progress :1;
150 BOOL smtp_exit_function_called :1;
151 #ifdef SUPPORT_I18N
152 BOOL smtputf8_advertised :1;
153 #endif
154 } fl = {
155 .helo_required = FALSE,
156 .helo_verify = FALSE,
157 .smtp_exit_function_called = FALSE,
158 };
159
160 static auth_instance *authenticated_by;
161 static int count_nonmail;
162 static int nonmail_command_count;
163 static int synprot_error_count;
164 static int unknown_command_count;
165 static int sync_cmd_limit;
166 static int smtp_write_error = 0;
167
168 static uschar *rcpt_smtp_response;
169 static uschar *smtp_data_buffer;
170 static uschar *smtp_cmd_data;
171
172 /* We need to know the position of RSET, HELO, EHLO, AUTH, and STARTTLS. Their
173 final fields of all except AUTH are forced TRUE at the start of a new message
174 setup, to allow one of each between messages that is not counted as a nonmail
175 command. (In fact, only one of HELO/EHLO is not counted.) Also, we have to
176 allow a new EHLO after starting up TLS.
177
178 AUTH is "falsely" labelled as a mail command initially, so that it doesn't get
179 counted. However, the flag is changed when AUTH is received, so that multiple
180 failing AUTHs will eventually hit the limit. After a successful AUTH, another
181 AUTH is already forbidden. After a TLS session is started, AUTH's flag is again
182 forced TRUE, to allow for the re-authentication that can happen at that point.
183
184 QUIT is also "falsely" labelled as a mail command so that it doesn't up the
185 count of non-mail commands and possibly provoke an error.
186
187 tls_auth is a pseudo-command, never expected in input. It is activated
188 on TLS startup and looks for a tls authenticator. */
189
190 static smtp_cmd_list cmd_list[] = {
191 /* name len cmd has_arg is_mail_cmd */
192
193 { "rset", sizeof("rset")-1, RSET_CMD, FALSE, FALSE }, /* First */
194 { "helo", sizeof("helo")-1, HELO_CMD, TRUE, FALSE },
195 { "ehlo", sizeof("ehlo")-1, EHLO_CMD, TRUE, FALSE },
196 { "auth", sizeof("auth")-1, AUTH_CMD, TRUE, TRUE },
197 #ifdef SUPPORT_TLS
198 { "starttls", sizeof("starttls")-1, STARTTLS_CMD, FALSE, FALSE },
199 { "tls_auth", 0, TLS_AUTH_CMD, FALSE, FALSE },
200 #endif
201
202 /* If you change anything above here, also fix the definitions below. */
203
204 { "mail from:", sizeof("mail from:")-1, MAIL_CMD, TRUE, TRUE },
205 { "rcpt to:", sizeof("rcpt to:")-1, RCPT_CMD, TRUE, TRUE },
206 { "data", sizeof("data")-1, DATA_CMD, FALSE, TRUE },
207 { "bdat", sizeof("bdat")-1, BDAT_CMD, TRUE, TRUE },
208 { "quit", sizeof("quit")-1, QUIT_CMD, FALSE, TRUE },
209 { "noop", sizeof("noop")-1, NOOP_CMD, TRUE, FALSE },
210 { "etrn", sizeof("etrn")-1, ETRN_CMD, TRUE, FALSE },
211 { "vrfy", sizeof("vrfy")-1, VRFY_CMD, TRUE, FALSE },
212 { "expn", sizeof("expn")-1, EXPN_CMD, TRUE, FALSE },
213 { "help", sizeof("help")-1, HELP_CMD, TRUE, FALSE }
214 };
215
216 static smtp_cmd_list *cmd_list_end =
217 cmd_list + sizeof(cmd_list)/sizeof(smtp_cmd_list);
218
219 #define CMD_LIST_RSET 0
220 #define CMD_LIST_HELO 1
221 #define CMD_LIST_EHLO 2
222 #define CMD_LIST_AUTH 3
223 #define CMD_LIST_STARTTLS 4
224 #define CMD_LIST_TLS_AUTH 5
225
226 /* This list of names is used for performing the smtp_no_mail logging action.
227 It must be kept in step with the SCH_xxx enumerations. */
228
229 static uschar *smtp_names[] =
230 {
231 US"NONE", US"AUTH", US"DATA", US"BDAT", US"EHLO", US"ETRN", US"EXPN",
232 US"HELO", US"HELP", US"MAIL", US"NOOP", US"QUIT", US"RCPT", US"RSET",
233 US"STARTTLS", US"VRFY" };
234
235 static uschar *protocols_local[] = {
236 US"local-smtp", /* HELO */
237 US"local-smtps", /* The rare case EHLO->STARTTLS->HELO */
238 US"local-esmtp", /* EHLO */
239 US"local-esmtps", /* EHLO->STARTTLS->EHLO */
240 US"local-esmtpa", /* EHLO->AUTH */
241 US"local-esmtpsa" /* EHLO->STARTTLS->EHLO->AUTH */
242 };
243 static uschar *protocols[] = {
244 US"smtp", /* HELO */
245 US"smtps", /* The rare case EHLO->STARTTLS->HELO */
246 US"esmtp", /* EHLO */
247 US"esmtps", /* EHLO->STARTTLS->EHLO */
248 US"esmtpa", /* EHLO->AUTH */
249 US"esmtpsa" /* EHLO->STARTTLS->EHLO->AUTH */
250 };
251
252 #define pnormal 0
253 #define pextend 2
254 #define pcrpted 1 /* added to pextend or pnormal */
255 #define pauthed 2 /* added to pextend */
256
257 /* Sanity check and validate optional args to MAIL FROM: envelope */
258 enum {
259 ENV_MAIL_OPT_NULL,
260 ENV_MAIL_OPT_SIZE, ENV_MAIL_OPT_BODY, ENV_MAIL_OPT_AUTH,
261 #ifndef DISABLE_PRDR
262 ENV_MAIL_OPT_PRDR,
263 #endif
264 ENV_MAIL_OPT_RET, ENV_MAIL_OPT_ENVID,
265 #ifdef SUPPORT_I18N
266 ENV_MAIL_OPT_UTF8,
267 #endif
268 #ifdef EXPERIMENTAL_REQUIRETLS
269 ENV_MAIL_OPT_REQTLS,
270 #endif
271 };
272 typedef struct {
273 uschar * name; /* option requested during MAIL cmd */
274 int value; /* enum type */
275 BOOL need_value; /* TRUE requires value (name=value pair format)
276 FALSE is a singleton */
277 } env_mail_type_t;
278 static env_mail_type_t env_mail_type_list[] = {
279 { US"SIZE", ENV_MAIL_OPT_SIZE, TRUE },
280 { US"BODY", ENV_MAIL_OPT_BODY, TRUE },
281 { US"AUTH", ENV_MAIL_OPT_AUTH, TRUE },
282 #ifndef DISABLE_PRDR
283 { US"PRDR", ENV_MAIL_OPT_PRDR, FALSE },
284 #endif
285 { US"RET", ENV_MAIL_OPT_RET, TRUE },
286 { US"ENVID", ENV_MAIL_OPT_ENVID, TRUE },
287 #ifdef SUPPORT_I18N
288 { US"SMTPUTF8",ENV_MAIL_OPT_UTF8, FALSE }, /* rfc6531 */
289 #endif
290 #ifdef EXPERIMENTAL_REQUIRETLS
291 /* https://tools.ietf.org/html/draft-ietf-uta-smtp-require-tls-03 */
292 { US"REQUIRETLS",ENV_MAIL_OPT_REQTLS, FALSE },
293 #endif
294 /* keep this the last entry */
295 { US"NULL", ENV_MAIL_OPT_NULL, FALSE },
296 };
297
298 /* When reading SMTP from a remote host, we have to use our own versions of the
299 C input-reading functions, in order to be able to flush the SMTP output only
300 when about to read more data from the socket. This is the only way to get
301 optimal performance when the client is using pipelining. Flushing for every
302 command causes a separate packet and reply packet each time; saving all the
303 responses up (when pipelining) combines them into one packet and one response.
304
305 For simplicity, these functions are used for *all* SMTP input, not only when
306 receiving over a socket. However, after setting up a secure socket (SSL), input
307 is read via the OpenSSL library, and another set of functions is used instead
308 (see tls.c).
309
310 These functions are set in the receive_getc etc. variables and called with the
311 same interface as the C functions. However, since there can only ever be
312 one incoming SMTP call, we just use a single buffer and flags. There is no need
313 to implement a complicated private FILE-like structure.*/
314
315 static uschar *smtp_inbuffer;
316 static uschar *smtp_inptr;
317 static uschar *smtp_inend;
318 static int smtp_had_eof;
319 static int smtp_had_error;
320
321
322 /* forward declarations */
323 static int smtp_read_command(BOOL check_sync, unsigned buffer_lim);
324 static int synprot_error(int type, int code, uschar *data, uschar *errmess);
325 static void smtp_quit_handler(uschar **, uschar **);
326 static void smtp_rset_handler(void);
327
328 /*************************************************
329 * Recheck synchronization *
330 *************************************************/
331
332 /* Synchronization checks can never be perfect because a packet may be on its
333 way but not arrived when the check is done. Normally, the checks happen when
334 commands are read: Exim ensures that there is no more input in the input buffer.
335 In normal cases, the response to the command will be fast, and there is no
336 further check.
337
338 However, for some commands an ACL is run, and that can include delays. In those
339 cases, it is useful to do another check on the input just before sending the
340 response. This also applies at the start of a connection. This function does
341 that check by means of the select() function, as long as the facility is not
342 disabled or inappropriate. A failure of select() is ignored.
343
344 When there is unwanted input, we read it so that it appears in the log of the
345 error.
346
347 Arguments: none
348 Returns: TRUE if all is well; FALSE if there is input pending
349 */
350
351 static BOOL
352 wouldblock_reading(void)
353 {
354 int fd, rc;
355 fd_set fds;
356 struct timeval tzero;
357
358 #ifdef SUPPORT_TLS
359 if (tls_in.active.sock >= 0)
360 return !tls_could_read();
361 #endif
362
363 if (smtp_inptr < smtp_inend)
364 return FALSE;
365
366 fd = fileno(smtp_in);
367 FD_ZERO(&fds);
368 FD_SET(fd, &fds);
369 tzero.tv_sec = 0;
370 tzero.tv_usec = 0;
371 rc = select(fd + 1, (SELECT_ARG2_TYPE *)&fds, NULL, NULL, &tzero);
372
373 if (rc <= 0) return TRUE; /* Not ready to read */
374 rc = smtp_getc(GETC_BUFFER_UNLIMITED);
375 if (rc < 0) return TRUE; /* End of file or error */
376
377 smtp_ungetc(rc);
378 return FALSE;
379 }
380
381 static BOOL
382 check_sync(void)
383 {
384 if (!smtp_enforce_sync || !sender_host_address || f.sender_host_notsocket)
385 return TRUE;
386
387 return wouldblock_reading();
388 }
389
390
391 /* If there's input waiting (and we're doing pipelineing) then we can pipeline
392 a reponse with the one following. */
393
394 static BOOL
395 pipeline_response(void)
396 {
397 if ( !smtp_enforce_sync || !sender_host_address
398 || f.sender_host_notsocket || !f.smtp_in_pipelining_advertised)
399 return FALSE;
400
401 if (wouldblock_reading()) return FALSE;
402 f.smtp_in_pipelining_used = TRUE;
403 return TRUE;
404 }
405
406
407
408 /*************************************************
409 * Log incomplete transactions *
410 *************************************************/
411
412 /* This function is called after a transaction has been aborted by RSET, QUIT,
413 connection drops or other errors. It logs the envelope information received
414 so far in order to preserve address verification attempts.
415
416 Argument: string to indicate what aborted the transaction
417 Returns: nothing
418 */
419
420 static void
421 incomplete_transaction_log(uschar *what)
422 {
423 if (sender_address == NULL || /* No transaction in progress */
424 !LOGGING(smtp_incomplete_transaction))
425 return;
426
427 /* Build list of recipients for logging */
428
429 if (recipients_count > 0)
430 {
431 int i;
432 raw_recipients = store_get(recipients_count * sizeof(uschar *));
433 for (i = 0; i < recipients_count; i++)
434 raw_recipients[i] = recipients_list[i].address;
435 raw_recipients_count = recipients_count;
436 }
437
438 log_write(L_smtp_incomplete_transaction, LOG_MAIN|LOG_SENDER|LOG_RECIPIENTS,
439 "%s incomplete transaction (%s)", host_and_ident(TRUE), what);
440 }
441
442
443
444
445 void
446 smtp_command_timeout_exit(void)
447 {
448 log_write(L_lost_incoming_connection,
449 LOG_MAIN, "SMTP command timeout on%s connection from %s",
450 tls_in.active.sock >= 0 ? " TLS" : "", host_and_ident(FALSE));
451 if (smtp_batched_input)
452 moan_smtp_batch(NULL, "421 SMTP command timeout"); /* Does not return */
453 smtp_notquit_exit(US"command-timeout", US"421",
454 US"%s: SMTP command timeout - closing connection",
455 smtp_active_hostname);
456 exim_exit(EXIT_FAILURE, US"receiving");
457 }
458
459 void
460 smtp_command_sigterm_exit(void)
461 {
462 log_write(0, LOG_MAIN, "%s closed after SIGTERM", smtp_get_connection_info());
463 if (smtp_batched_input)
464 moan_smtp_batch(NULL, "421 SIGTERM received"); /* Does not return */
465 smtp_notquit_exit(US"signal-exit", US"421",
466 US"%s: Service not available - closing connection", smtp_active_hostname);
467 exim_exit(EXIT_FAILURE, US"receiving");
468 }
469
470 void
471 smtp_data_timeout_exit(void)
472 {
473 log_write(L_lost_incoming_connection,
474 LOG_MAIN, "SMTP data timeout (message abandoned) on connection from %s F=<%s>",
475 sender_fullhost ? sender_fullhost : US"local process", sender_address);
476 receive_bomb_out(US"data-timeout", US"SMTP incoming data timeout");
477 /* Does not return */
478 }
479
480 void
481 smtp_data_sigint_exit(void)
482 {
483 log_write(0, LOG_MAIN, "%s closed after %s",
484 smtp_get_connection_info(), had_data_sigint == SIGTERM ? "SIGTERM":"SIGINT");
485 receive_bomb_out(US"signal-exit",
486 US"Service not available - SIGTERM or SIGINT received");
487 /* Does not return */
488 }
489
490
491
492 /* Refill the buffer, and notify DKIM verification code.
493 Return false for error or EOF.
494 */
495
496 static BOOL
497 smtp_refill(unsigned lim)
498 {
499 int rc, save_errno;
500 if (!smtp_out) return FALSE;
501 fflush(smtp_out);
502 if (smtp_receive_timeout > 0) alarm(smtp_receive_timeout);
503
504 /* Limit amount read, so non-message data is not fed to DKIM.
505 Take care to not touch the safety NUL at the end of the buffer. */
506
507 rc = read(fileno(smtp_in), smtp_inbuffer, MIN(IN_BUFFER_SIZE-1, lim));
508 save_errno = errno;
509 if (smtp_receive_timeout > 0) alarm(0);
510 if (rc <= 0)
511 {
512 /* Must put the error text in fixed store, because this might be during
513 header reading, where it releases unused store above the header. */
514 if (rc < 0)
515 {
516 if (had_command_timeout) /* set by signal handler */
517 smtp_command_timeout_exit(); /* does not return */
518 if (had_command_sigterm)
519 smtp_command_sigterm_exit();
520 if (had_data_timeout)
521 smtp_data_timeout_exit();
522 if (had_data_sigint)
523 smtp_data_sigint_exit();
524
525 smtp_had_error = save_errno;
526 smtp_read_error = string_copy_malloc(
527 string_sprintf(" (error: %s)", strerror(save_errno)));
528 }
529 else
530 smtp_had_eof = 1;
531 return FALSE;
532 }
533 #ifndef DISABLE_DKIM
534 dkim_exim_verify_feed(smtp_inbuffer, rc);
535 #endif
536 smtp_inend = smtp_inbuffer + rc;
537 smtp_inptr = smtp_inbuffer;
538 return TRUE;
539 }
540
541 /*************************************************
542 * SMTP version of getc() *
543 *************************************************/
544
545 /* This gets the next byte from the SMTP input buffer. If the buffer is empty,
546 it flushes the output, and refills the buffer, with a timeout. The signal
547 handler is set appropriately by the calling function. This function is not used
548 after a connection has negotiated itself into an TLS/SSL state.
549
550 Arguments: lim Maximum amount to read/buffer
551 Returns: the next character or EOF
552 */
553
554 int
555 smtp_getc(unsigned lim)
556 {
557 if (smtp_inptr >= smtp_inend)
558 if (!smtp_refill(lim))
559 return EOF;
560 return *smtp_inptr++;
561 }
562
563 uschar *
564 smtp_getbuf(unsigned * len)
565 {
566 unsigned size;
567 uschar * buf;
568
569 if (smtp_inptr >= smtp_inend)
570 if (!smtp_refill(*len))
571 { *len = 0; return NULL; }
572
573 if ((size = smtp_inend - smtp_inptr) > *len) size = *len;
574 buf = smtp_inptr;
575 smtp_inptr += size;
576 *len = size;
577 return buf;
578 }
579
580 void
581 smtp_get_cache(void)
582 {
583 #ifndef DISABLE_DKIM
584 int n = smtp_inend - smtp_inptr;
585 if (n > 0)
586 dkim_exim_verify_feed(smtp_inptr, n);
587 #endif
588 }
589
590
591 /* Get a byte from the smtp input, in CHUNKING mode. Handle ack of the
592 previous BDAT chunk and getting new ones when we run out. Uses the
593 underlying smtp_getc or tls_getc both for that and for getting the
594 (buffered) data byte. EOD signals (an expected) no further data.
595 ERR signals a protocol error, and EOF a closed input stream.
596
597 Called from read_bdat_smtp() in receive.c for the message body, but also
598 by the headers read loop in receive_msg(); manipulates chunking_state
599 to handle the BDAT command/response.
600 Placed here due to the correlation with the above smtp_getc(), which it wraps,
601 and also by the need to do smtp command/response handling.
602
603 Arguments: lim (ignored)
604 Returns: the next character or ERR, EOD or EOF
605 */
606
607 int
608 bdat_getc(unsigned lim)
609 {
610 uschar * user_msg = NULL;
611 uschar * log_msg;
612
613 for(;;)
614 {
615 #ifndef DISABLE_DKIM
616 unsigned dkim_save;
617 #endif
618
619 if (chunking_data_left > 0)
620 return lwr_receive_getc(chunking_data_left--);
621
622 receive_getc = lwr_receive_getc;
623 receive_getbuf = lwr_receive_getbuf;
624 receive_ungetc = lwr_receive_ungetc;
625 #ifndef DISABLE_DKIM
626 dkim_save = dkim_collect_input;
627 dkim_collect_input = 0;
628 #endif
629
630 /* Unless PIPELINING was offered, there should be no next command
631 until after we ack that chunk */
632
633 if (!f.smtp_in_pipelining_advertised && !check_sync())
634 {
635 unsigned n = smtp_inend - smtp_inptr;
636 if (n > 32) n = 32;
637
638 incomplete_transaction_log(US"sync failure");
639 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP protocol synchronization error "
640 "(next input sent too soon: pipelining was not advertised): "
641 "rejected \"%s\" %s next input=\"%s\"%s",
642 smtp_cmd_buffer, host_and_ident(TRUE),
643 string_printing(string_copyn(smtp_inptr, n)),
644 smtp_inend - smtp_inptr > n ? "..." : "");
645 (void) synprot_error(L_smtp_protocol_error, 554, NULL,
646 US"SMTP synchronization error");
647 goto repeat_until_rset;
648 }
649
650 /* If not the last, ack the received chunk. The last response is delayed
651 until after the data ACL decides on it */
652
653 if (chunking_state == CHUNKING_LAST)
654 {
655 #ifndef DISABLE_DKIM
656 dkim_exim_verify_feed(NULL, 0); /* notify EOD */
657 #endif
658 return EOD;
659 }
660
661 smtp_printf("250 %u byte chunk received\r\n", FALSE, chunking_datasize);
662 chunking_state = CHUNKING_OFFERED;
663 DEBUG(D_receive) debug_printf("chunking state %d\n", (int)chunking_state);
664
665 /* Expect another BDAT cmd from input. RFC 3030 says nothing about
666 QUIT, RSET or NOOP but handling them seems obvious */
667
668 next_cmd:
669 switch(smtp_read_command(TRUE, 1))
670 {
671 default:
672 (void) synprot_error(L_smtp_protocol_error, 503, NULL,
673 US"only BDAT permissible after non-LAST BDAT");
674
675 repeat_until_rset:
676 switch(smtp_read_command(TRUE, 1))
677 {
678 case QUIT_CMD: smtp_quit_handler(&user_msg, &log_msg); /*FALLTHROUGH */
679 case EOF_CMD: return EOF;
680 case RSET_CMD: smtp_rset_handler(); return ERR;
681 default: if (synprot_error(L_smtp_protocol_error, 503, NULL,
682 US"only RSET accepted now") > 0)
683 return EOF;
684 goto repeat_until_rset;
685 }
686
687 case QUIT_CMD:
688 smtp_quit_handler(&user_msg, &log_msg);
689 /*FALLTHROUGH*/
690 case EOF_CMD:
691 return EOF;
692
693 case RSET_CMD:
694 smtp_rset_handler();
695 return ERR;
696
697 case NOOP_CMD:
698 HAD(SCH_NOOP);
699 smtp_printf("250 OK\r\n", FALSE);
700 goto next_cmd;
701
702 case BDAT_CMD:
703 {
704 int n;
705
706 if (sscanf(CS smtp_cmd_data, "%u %n", &chunking_datasize, &n) < 1)
707 {
708 (void) synprot_error(L_smtp_protocol_error, 501, NULL,
709 US"missing size for BDAT command");
710 return ERR;
711 }
712 chunking_state = strcmpic(smtp_cmd_data+n, US"LAST") == 0
713 ? CHUNKING_LAST : CHUNKING_ACTIVE;
714 chunking_data_left = chunking_datasize;
715 DEBUG(D_receive) debug_printf("chunking state %d, %d bytes\n",
716 (int)chunking_state, chunking_data_left);
717
718 if (chunking_datasize == 0)
719 if (chunking_state == CHUNKING_LAST)
720 return EOD;
721 else
722 {
723 (void) synprot_error(L_smtp_protocol_error, 504, NULL,
724 US"zero size for BDAT command");
725 goto repeat_until_rset;
726 }
727
728 receive_getc = bdat_getc;
729 receive_getbuf = bdat_getbuf; /* r~getbuf is never actually used */
730 receive_ungetc = bdat_ungetc;
731 #ifndef DISABLE_DKIM
732 dkim_collect_input = dkim_save;
733 #endif
734 break; /* to top of main loop */
735 }
736 }
737 }
738 }
739
740 uschar *
741 bdat_getbuf(unsigned * len)
742 {
743 uschar * buf;
744
745 if (chunking_data_left <= 0)
746 { *len = 0; return NULL; }
747
748 if (*len > chunking_data_left) *len = chunking_data_left;
749 buf = lwr_receive_getbuf(len); /* Either smtp_getbuf or tls_getbuf */
750 chunking_data_left -= *len;
751 return buf;
752 }
753
754 void
755 bdat_flush_data(void)
756 {
757 while (chunking_data_left)
758 {
759 unsigned n = chunking_data_left;
760 if (!bdat_getbuf(&n)) break;
761 }
762
763 receive_getc = lwr_receive_getc;
764 receive_getbuf = lwr_receive_getbuf;
765 receive_ungetc = lwr_receive_ungetc;
766
767 if (chunking_state != CHUNKING_LAST)
768 {
769 chunking_state = CHUNKING_OFFERED;
770 DEBUG(D_receive) debug_printf("chunking state %d\n", (int)chunking_state);
771 }
772 }
773
774
775
776
777 /*************************************************
778 * SMTP version of ungetc() *
779 *************************************************/
780
781 /* Puts a character back in the input buffer. Only ever
782 called once.
783
784 Arguments:
785 ch the character
786
787 Returns: the character
788 */
789
790 int
791 smtp_ungetc(int ch)
792 {
793 *--smtp_inptr = ch;
794 return ch;
795 }
796
797
798 int
799 bdat_ungetc(int ch)
800 {
801 chunking_data_left++;
802 return lwr_receive_ungetc(ch);
803 }
804
805
806
807 /*************************************************
808 * SMTP version of feof() *
809 *************************************************/
810
811 /* Tests for a previous EOF
812
813 Arguments: none
814 Returns: non-zero if the eof flag is set
815 */
816
817 int
818 smtp_feof(void)
819 {
820 return smtp_had_eof;
821 }
822
823
824
825
826 /*************************************************
827 * SMTP version of ferror() *
828 *************************************************/
829
830 /* Tests for a previous read error, and returns with errno
831 restored to what it was when the error was detected.
832
833 Arguments: none
834 Returns: non-zero if the error flag is set
835 */
836
837 int
838 smtp_ferror(void)
839 {
840 errno = smtp_had_error;
841 return smtp_had_error;
842 }
843
844
845
846 /*************************************************
847 * Test for characters in the SMTP buffer *
848 *************************************************/
849
850 /* Used at the end of a message
851
852 Arguments: none
853 Returns: TRUE/FALSE
854 */
855
856 BOOL
857 smtp_buffered(void)
858 {
859 return smtp_inptr < smtp_inend;
860 }
861
862
863
864 /*************************************************
865 * Write formatted string to SMTP channel *
866 *************************************************/
867
868 /* This is a separate function so that we don't have to repeat everything for
869 TLS support or debugging. It is global so that the daemon and the
870 authentication functions can use it. It does not return any error indication,
871 because major problems such as dropped connections won't show up till an output
872 flush for non-TLS connections. The smtp_fflush() function is available for
873 checking that: for convenience, TLS output errors are remembered here so that
874 they are also picked up later by smtp_fflush().
875
876 Arguments:
877 format format string
878 more further data expected
879 ... optional arguments
880
881 Returns: nothing
882 */
883
884 void
885 smtp_printf(const char *format, BOOL more, ...)
886 {
887 va_list ap;
888
889 va_start(ap, more);
890 smtp_vprintf(format, more, ap);
891 va_end(ap);
892 }
893
894 /* This is split off so that verify.c:respond_printf() can, in effect, call
895 smtp_printf(), bearing in mind that in C a vararg function can't directly
896 call another vararg function, only a function which accepts a va_list. */
897
898 void
899 smtp_vprintf(const char *format, BOOL more, va_list ap)
900 {
901 BOOL yield;
902
903 yield = string_vformat(big_buffer, big_buffer_size, format, ap);
904
905 DEBUG(D_receive)
906 {
907 void *reset_point = store_get(0);
908 uschar *msg_copy, *cr, *end;
909 msg_copy = string_copy(big_buffer);
910 end = msg_copy + Ustrlen(msg_copy);
911 while ((cr = Ustrchr(msg_copy, '\r')) != NULL) /* lose CRs */
912 memmove(cr, cr + 1, (end--) - cr);
913 debug_printf("SMTP>> %s", msg_copy);
914 store_reset(reset_point);
915 }
916
917 if (!yield)
918 {
919 log_write(0, LOG_MAIN|LOG_PANIC, "string too large in smtp_printf()");
920 smtp_closedown(US"Unexpected error");
921 exim_exit(EXIT_FAILURE, NULL);
922 }
923
924 /* If this is the first output for a (non-batch) RCPT command, see if all RCPTs
925 have had the same. Note: this code is also present in smtp_respond(). It would
926 be tidier to have it only in one place, but when it was added, it was easier to
927 do it that way, so as not to have to mess with the code for the RCPT command,
928 which sometimes uses smtp_printf() and sometimes smtp_respond(). */
929
930 if (fl.rcpt_in_progress)
931 {
932 if (rcpt_smtp_response == NULL)
933 rcpt_smtp_response = string_copy(big_buffer);
934 else if (fl.rcpt_smtp_response_same &&
935 Ustrcmp(rcpt_smtp_response, big_buffer) != 0)
936 fl.rcpt_smtp_response_same = FALSE;
937 fl.rcpt_in_progress = FALSE;
938 }
939
940 /* Now write the string */
941
942 #ifdef SUPPORT_TLS
943 if (tls_in.active.sock >= 0)
944 {
945 if (tls_write(NULL, big_buffer, Ustrlen(big_buffer), more) < 0)
946 smtp_write_error = -1;
947 }
948 else
949 #endif
950
951 if (fprintf(smtp_out, "%s", big_buffer) < 0) smtp_write_error = -1;
952 }
953
954
955
956 /*************************************************
957 * Flush SMTP out and check for error *
958 *************************************************/
959
960 /* This function isn't currently used within Exim (it detects errors when it
961 tries to read the next SMTP input), but is available for use in local_scan().
962 For non-TLS connections, it flushes the output and checks for errors. For
963 TLS-connections, it checks for a previously-detected TLS write error.
964
965 Arguments: none
966 Returns: 0 for no error; -1 after an error
967 */
968
969 int
970 smtp_fflush(void)
971 {
972 if (tls_in.active.sock < 0 && fflush(smtp_out) != 0) smtp_write_error = -1;
973 return smtp_write_error;
974 }
975
976
977
978 /*************************************************
979 * SMTP command read timeout *
980 *************************************************/
981
982 /* Signal handler for timing out incoming SMTP commands. This attempts to
983 finish off tidily.
984
985 Argument: signal number (SIGALRM)
986 Returns: nothing
987 */
988
989 static void
990 command_timeout_handler(int sig)
991 {
992 had_command_timeout = sig;
993 }
994
995
996
997 /*************************************************
998 * SIGTERM received *
999 *************************************************/
1000
1001 /* Signal handler for handling SIGTERM. Again, try to finish tidily.
1002
1003 Argument: signal number (SIGTERM)
1004 Returns: nothing
1005 */
1006
1007 static void
1008 command_sigterm_handler(int sig)
1009 {
1010 had_command_sigterm = sig;
1011 }
1012
1013
1014
1015
1016 #ifdef SUPPORT_PROXY
1017 /*************************************************
1018 * Restore socket timeout to previous value *
1019 *************************************************/
1020 /* If the previous value was successfully retrieved, restore
1021 it before returning control to the non-proxy routines
1022
1023 Arguments: fd - File descriptor for input
1024 get_ok - Successfully retrieved previous values
1025 tvtmp - Time struct with previous values
1026 vslen - Length of time struct
1027 Returns: none
1028 */
1029 static void
1030 restore_socket_timeout(int fd, int get_ok, struct timeval * tvtmp, socklen_t vslen)
1031 {
1032 if (get_ok == 0)
1033 (void) setsockopt(fd, SOL_SOCKET, SO_RCVTIMEO, CS tvtmp, vslen);
1034 }
1035
1036 /*************************************************
1037 * Check if host is required proxy host *
1038 *************************************************/
1039 /* The function determines if inbound host will be a regular smtp host
1040 or if it is configured that it must use Proxy Protocol. A local
1041 connection cannot.
1042
1043 Arguments: none
1044 Returns: bool
1045 */
1046
1047 static BOOL
1048 check_proxy_protocol_host()
1049 {
1050 int rc;
1051
1052 if ( sender_host_address
1053 && (rc = verify_check_this_host(CUSS &hosts_proxy, NULL, NULL,
1054 sender_host_address, NULL)) == OK)
1055 {
1056 DEBUG(D_receive)
1057 debug_printf("Detected proxy protocol configured host\n");
1058 proxy_session = TRUE;
1059 }
1060 return proxy_session;
1061 }
1062
1063
1064 /*************************************************
1065 * Read data until newline or end of buffer *
1066 *************************************************/
1067 /* While SMTP is server-speaks-first, TLS is client-speaks-first, so we can't
1068 read an entire buffer and assume there will be nothing past a proxy protocol
1069 header. Our approach normally is to use stdio, but again that relies upon
1070 "STARTTLS\r\n" and a server response before the client starts TLS handshake, or
1071 reading _nothing_ before client TLS handshake. So we don't want to use the
1072 usual buffering reads which may read enough to block TLS starting.
1073
1074 So unfortunately we're down to "read one byte at a time, with a syscall each,
1075 and expect a little overhead", for all proxy-opened connections which are v1,
1076 just to handle the TLS-on-connect case. Since SSL functions wrap the
1077 underlying fd, we can't assume that we can feed them any already-read content.
1078
1079 We need to know where to read to, the max capacity, and we'll read until we
1080 get a CR and one more character. Let the caller scream if it's CR+!LF.
1081
1082 Return the amount read.
1083 */
1084
1085 static int
1086 swallow_until_crlf(int fd, uschar *base, int already, int capacity)
1087 {
1088 uschar *to = base + already;
1089 uschar *cr;
1090 int have = 0;
1091 int ret;
1092 int last = 0;
1093
1094 /* For "PROXY UNKNOWN\r\n" we, at time of writing, expect to have read
1095 up through the \r; for the _normal_ case, we haven't yet seen the \r. */
1096
1097 cr = memchr(base, '\r', already);
1098 if (cr != NULL)
1099 {
1100 if ((cr - base) < already - 1)
1101 {
1102 /* \r and presumed \n already within what we have; probably not
1103 actually proxy protocol, but abort cleanly. */
1104 return 0;
1105 }
1106 /* \r is last character read, just need one more. */
1107 last = 1;
1108 }
1109
1110 while (capacity > 0)
1111 {
1112 do { ret = recv(fd, to, 1, 0); } while (ret == -1 && errno == EINTR);
1113 if (ret == -1)
1114 return -1;
1115 have++;
1116 if (last)
1117 return have;
1118 if (*to == '\r')
1119 last = 1;
1120 capacity--;
1121 to++;
1122 }
1123
1124 /* reached end without having room for a final newline, abort */
1125 errno = EOVERFLOW;
1126 return -1;
1127 }
1128
1129 /*************************************************
1130 * Setup host for proxy protocol *
1131 *************************************************/
1132 /* The function configures the connection based on a header from the
1133 inbound host to use Proxy Protocol. The specification is very exact
1134 so exit with an error if do not find the exact required pieces. This
1135 includes an incorrect number of spaces separating args.
1136
1137 Arguments: none
1138 Returns: Boolean success
1139 */
1140
1141 static void
1142 setup_proxy_protocol_host()
1143 {
1144 union {
1145 struct {
1146 uschar line[108];
1147 } v1;
1148 struct {
1149 uschar sig[12];
1150 uint8_t ver_cmd;
1151 uint8_t fam;
1152 uint16_t len;
1153 union {
1154 struct { /* TCP/UDP over IPv4, len = 12 */
1155 uint32_t src_addr;
1156 uint32_t dst_addr;
1157 uint16_t src_port;
1158 uint16_t dst_port;
1159 } ip4;
1160 struct { /* TCP/UDP over IPv6, len = 36 */
1161 uint8_t src_addr[16];
1162 uint8_t dst_addr[16];
1163 uint16_t src_port;
1164 uint16_t dst_port;
1165 } ip6;
1166 struct { /* AF_UNIX sockets, len = 216 */
1167 uschar src_addr[108];
1168 uschar dst_addr[108];
1169 } unx;
1170 } addr;
1171 } v2;
1172 } hdr;
1173
1174 /* Temp variables used in PPv2 address:port parsing */
1175 uint16_t tmpport;
1176 char tmpip[INET_ADDRSTRLEN];
1177 struct sockaddr_in tmpaddr;
1178 char tmpip6[INET6_ADDRSTRLEN];
1179 struct sockaddr_in6 tmpaddr6;
1180
1181 /* We can't read "all data until end" because while SMTP is
1182 server-speaks-first, the TLS handshake is client-speaks-first, so for
1183 TLS-on-connect ports the proxy protocol header will usually be immediately
1184 followed by a TLS handshake, and with N TLS libraries, we can't reliably
1185 reinject data for reading by those. So instead we first read "enough to be
1186 safely read within the header, and figure out how much more to read".
1187 For v1 we will later read to the end-of-line, for v2 we will read based upon
1188 the stated length.
1189
1190 The v2 sig is 12 octets, and another 4 gets us the length, so we know how much
1191 data is needed total. For v1, where the line looks like:
1192 PROXY TCPn L3src L3dest SrcPort DestPort \r\n
1193
1194 However, for v1 there's also `PROXY UNKNOWN\r\n` which is only 15 octets.
1195 We seem to support that. So, if we read 14 octets then we can tell if we're
1196 v2 or v1. If we're v1, we can continue reading as normal.
1197
1198 If we're v2, we can't slurp up the entire header. We need the length in the
1199 15th & 16th octets, then to read everything after that.
1200
1201 So to safely handle v1 and v2, with client-sent-first supported correctly,
1202 we have to do a minimum of 3 read calls, not 1. Eww.
1203 */
1204
1205 #define PROXY_INITIAL_READ 14
1206 #define PROXY_V2_HEADER_SIZE 16
1207 #if PROXY_INITIAL_READ > PROXY_V2_HEADER_SIZE
1208 # error Code bug in sizes of data to read for proxy usage
1209 #endif
1210
1211 int get_ok = 0;
1212 int size, ret;
1213 int fd = fileno(smtp_in);
1214 const char v2sig[12] = "\x0D\x0A\x0D\x0A\x00\x0D\x0A\x51\x55\x49\x54\x0A";
1215 uschar * iptype; /* To display debug info */
1216 struct timeval tv;
1217 struct timeval tvtmp;
1218 socklen_t vslen = sizeof(struct timeval);
1219 BOOL yield = FALSE;
1220
1221 /* Save current socket timeout values */
1222 get_ok = getsockopt(fd, SOL_SOCKET, SO_RCVTIMEO, CS &tvtmp, &vslen);
1223
1224 /* Proxy Protocol host must send header within a short time
1225 (default 3 seconds) or it's considered invalid */
1226 tv.tv_sec = PROXY_NEGOTIATION_TIMEOUT_SEC;
1227 tv.tv_usec = PROXY_NEGOTIATION_TIMEOUT_USEC;
1228 if (setsockopt(fd, SOL_SOCKET, SO_RCVTIMEO, CS &tv, sizeof(tv)) < 0)
1229 goto bad;
1230
1231 do
1232 {
1233 /* The inbound host was declared to be a Proxy Protocol host, so
1234 don't do a PEEK into the data, actually slurp up enough to be
1235 "safe". Can't take it all because TLS-on-connect clients follow
1236 immediately with TLS handshake. */
1237 ret = recv(fd, &hdr, PROXY_INITIAL_READ, 0);
1238 }
1239 while (ret == -1 && errno == EINTR);
1240
1241 if (ret == -1)
1242 goto proxyfail;
1243
1244 /* For v2, handle reading the length, and then the rest. */
1245 if ((ret == PROXY_INITIAL_READ) && (memcmp(&hdr.v2, v2sig, sizeof(v2sig)) == 0))
1246 {
1247 int retmore;
1248 uint8_t ver;
1249
1250 /* First get the length fields. */
1251 do
1252 {
1253 retmore = recv(fd, (uschar*)&hdr + ret, PROXY_V2_HEADER_SIZE - PROXY_INITIAL_READ, 0);
1254 } while (retmore == -1 && errno == EINTR);
1255 if (retmore == -1)
1256 goto proxyfail;
1257 ret += retmore;
1258
1259 ver = (hdr.v2.ver_cmd & 0xf0) >> 4;
1260
1261 /* May 2014: haproxy combined the version and command into one byte to
1262 allow two full bytes for the length field in order to proxy SSL
1263 connections. SSL Proxy is not supported in this version of Exim, but
1264 must still separate values here. */
1265
1266 if (ver != 0x02)
1267 {
1268 DEBUG(D_receive) debug_printf("Invalid Proxy Protocol version: %d\n", ver);
1269 goto proxyfail;
1270 }
1271
1272 /* The v2 header will always be 16 bytes per the spec. */
1273 size = 16 + ntohs(hdr.v2.len);
1274 DEBUG(D_receive) debug_printf("Detected PROXYv2 header, size %d (limit %d)\n",
1275 size, (int)sizeof(hdr));
1276
1277 /* We should now have 16 octets (PROXY_V2_HEADER_SIZE), and we know the total
1278 amount that we need. Double-check that the size is not unreasonable, then
1279 get the rest. */
1280 if (size > sizeof(hdr))
1281 {
1282 DEBUG(D_receive) debug_printf("PROXYv2 header size unreasonably large; security attack?\n");
1283 goto proxyfail;
1284 }
1285
1286 do
1287 {
1288 do
1289 {
1290 retmore = recv(fd, (uschar*)&hdr + ret, size-ret, 0);
1291 } while (retmore == -1 && errno == EINTR);
1292 if (retmore == -1)
1293 goto proxyfail;
1294 ret += retmore;
1295 DEBUG(D_receive) debug_printf("PROXYv2: have %d/%d required octets\n", ret, size);
1296 } while (ret < size);
1297
1298 } /* end scope for getting rest of data for v2 */
1299
1300 /* At this point: if PROXYv2, we've read the exact size required for all data;
1301 if PROXYv1 then we've read "less than required for any valid line" and should
1302 read the rest". */
1303
1304 if (ret >= 16 && memcmp(&hdr.v2, v2sig, 12) == 0)
1305 {
1306 uint8_t cmd = (hdr.v2.ver_cmd & 0x0f);
1307
1308 switch (cmd)
1309 {
1310 case 0x01: /* PROXY command */
1311 switch (hdr.v2.fam)
1312 {
1313 case 0x11: /* TCPv4 address type */
1314 iptype = US"IPv4";
1315 tmpaddr.sin_addr.s_addr = hdr.v2.addr.ip4.src_addr;
1316 inet_ntop(AF_INET, &tmpaddr.sin_addr, CS &tmpip, sizeof(tmpip));
1317 if (!string_is_ip_address(US tmpip, NULL))
1318 {
1319 DEBUG(D_receive) debug_printf("Invalid %s source IP\n", iptype);
1320 goto proxyfail;
1321 }
1322 proxy_local_address = sender_host_address;
1323 sender_host_address = string_copy(US tmpip);
1324 tmpport = ntohs(hdr.v2.addr.ip4.src_port);
1325 proxy_local_port = sender_host_port;
1326 sender_host_port = tmpport;
1327 /* Save dest ip/port */
1328 tmpaddr.sin_addr.s_addr = hdr.v2.addr.ip4.dst_addr;
1329 inet_ntop(AF_INET, &tmpaddr.sin_addr, CS &tmpip, sizeof(tmpip));
1330 if (!string_is_ip_address(US tmpip, NULL))
1331 {
1332 DEBUG(D_receive) debug_printf("Invalid %s dest port\n", iptype);
1333 goto proxyfail;
1334 }
1335 proxy_external_address = string_copy(US tmpip);
1336 tmpport = ntohs(hdr.v2.addr.ip4.dst_port);
1337 proxy_external_port = tmpport;
1338 goto done;
1339 case 0x21: /* TCPv6 address type */
1340 iptype = US"IPv6";
1341 memmove(tmpaddr6.sin6_addr.s6_addr, hdr.v2.addr.ip6.src_addr, 16);
1342 inet_ntop(AF_INET6, &tmpaddr6.sin6_addr, CS &tmpip6, sizeof(tmpip6));
1343 if (!string_is_ip_address(US tmpip6, NULL))
1344 {
1345 DEBUG(D_receive) debug_printf("Invalid %s source IP\n", iptype);
1346 goto proxyfail;
1347 }
1348 proxy_local_address = sender_host_address;
1349 sender_host_address = string_copy(US tmpip6);
1350 tmpport = ntohs(hdr.v2.addr.ip6.src_port);
1351 proxy_local_port = sender_host_port;
1352 sender_host_port = tmpport;
1353 /* Save dest ip/port */
1354 memmove(tmpaddr6.sin6_addr.s6_addr, hdr.v2.addr.ip6.dst_addr, 16);
1355 inet_ntop(AF_INET6, &tmpaddr6.sin6_addr, CS &tmpip6, sizeof(tmpip6));
1356 if (!string_is_ip_address(US tmpip6, NULL))
1357 {
1358 DEBUG(D_receive) debug_printf("Invalid %s dest port\n", iptype);
1359 goto proxyfail;
1360 }
1361 proxy_external_address = string_copy(US tmpip6);
1362 tmpport = ntohs(hdr.v2.addr.ip6.dst_port);
1363 proxy_external_port = tmpport;
1364 goto done;
1365 default:
1366 DEBUG(D_receive)
1367 debug_printf("Unsupported PROXYv2 connection type: 0x%02x\n",
1368 hdr.v2.fam);
1369 goto proxyfail;
1370 }
1371 /* Unsupported protocol, keep local connection address */
1372 break;
1373 case 0x00: /* LOCAL command */
1374 /* Keep local connection address for LOCAL */
1375 iptype = US"local";
1376 break;
1377 default:
1378 DEBUG(D_receive)
1379 debug_printf("Unsupported PROXYv2 command: 0x%x\n", cmd);
1380 goto proxyfail;
1381 }
1382 }
1383 else if (ret >= 8 && memcmp(hdr.v1.line, "PROXY", 5) == 0)
1384 {
1385 uschar *p;
1386 uschar *end;
1387 uschar *sp; /* Utility variables follow */
1388 int tmp_port;
1389 int r2;
1390 char *endc;
1391
1392 /* get the rest of the line */
1393 r2 = swallow_until_crlf(fd, (uschar*)&hdr, ret, sizeof(hdr)-ret);
1394 if (r2 == -1)
1395 goto proxyfail;
1396 ret += r2;
1397
1398 p = string_copy(hdr.v1.line);
1399 end = memchr(p, '\r', ret - 1);
1400
1401 if (!end || (end == (uschar*)&hdr + ret) || end[1] != '\n')
1402 {
1403 DEBUG(D_receive) debug_printf("Partial or invalid PROXY header\n");
1404 goto proxyfail;
1405 }
1406 *end = '\0'; /* Terminate the string */
1407 size = end + 2 - p; /* Skip header + CRLF */
1408 DEBUG(D_receive) debug_printf("Detected PROXYv1 header\n");
1409 DEBUG(D_receive) debug_printf("Bytes read not within PROXY header: %d\n", ret - size);
1410 /* Step through the string looking for the required fields. Ensure
1411 strict adherence to required formatting, exit for any error. */
1412 p += 5;
1413 if (!isspace(*(p++)))
1414 {
1415 DEBUG(D_receive) debug_printf("Missing space after PROXY command\n");
1416 goto proxyfail;
1417 }
1418 if (!Ustrncmp(p, CCS"TCP4", 4))
1419 iptype = US"IPv4";
1420 else if (!Ustrncmp(p,CCS"TCP6", 4))
1421 iptype = US"IPv6";
1422 else if (!Ustrncmp(p,CCS"UNKNOWN", 7))
1423 {
1424 iptype = US"Unknown";
1425 goto done;
1426 }
1427 else
1428 {
1429 DEBUG(D_receive) debug_printf("Invalid TCP type\n");
1430 goto proxyfail;
1431 }
1432
1433 p += Ustrlen(iptype);
1434 if (!isspace(*(p++)))
1435 {
1436 DEBUG(D_receive) debug_printf("Missing space after TCP4/6 command\n");
1437 goto proxyfail;
1438 }
1439 /* Find the end of the arg */
1440 if ((sp = Ustrchr(p, ' ')) == NULL)
1441 {
1442 DEBUG(D_receive)
1443 debug_printf("Did not find proxied src %s\n", iptype);
1444 goto proxyfail;
1445 }
1446 *sp = '\0';
1447 if(!string_is_ip_address(p, NULL))
1448 {
1449 DEBUG(D_receive)
1450 debug_printf("Proxied src arg is not an %s address\n", iptype);
1451 goto proxyfail;
1452 }
1453 proxy_local_address = sender_host_address;
1454 sender_host_address = p;
1455 p = sp + 1;
1456 if ((sp = Ustrchr(p, ' ')) == NULL)
1457 {
1458 DEBUG(D_receive)
1459 debug_printf("Did not find proxy dest %s\n", iptype);
1460 goto proxyfail;
1461 }
1462 *sp = '\0';
1463 if(!string_is_ip_address(p, NULL))
1464 {
1465 DEBUG(D_receive)
1466 debug_printf("Proxy dest arg is not an %s address\n", iptype);
1467 goto proxyfail;
1468 }
1469 proxy_external_address = p;
1470 p = sp + 1;
1471 if ((sp = Ustrchr(p, ' ')) == NULL)
1472 {
1473 DEBUG(D_receive) debug_printf("Did not find proxied src port\n");
1474 goto proxyfail;
1475 }
1476 *sp = '\0';
1477 tmp_port = strtol(CCS p, &endc, 10);
1478 if (*endc || tmp_port == 0)
1479 {
1480 DEBUG(D_receive)
1481 debug_printf("Proxied src port '%s' not an integer\n", p);
1482 goto proxyfail;
1483 }
1484 proxy_local_port = sender_host_port;
1485 sender_host_port = tmp_port;
1486 p = sp + 1;
1487 if ((sp = Ustrchr(p, '\0')) == NULL)
1488 {
1489 DEBUG(D_receive) debug_printf("Did not find proxy dest port\n");
1490 goto proxyfail;
1491 }
1492 tmp_port = strtol(CCS p, &endc, 10);
1493 if (*endc || tmp_port == 0)
1494 {
1495 DEBUG(D_receive)
1496 debug_printf("Proxy dest port '%s' not an integer\n", p);
1497 goto proxyfail;
1498 }
1499 proxy_external_port = tmp_port;
1500 /* Already checked for /r /n above. Good V1 header received. */
1501 }
1502 else
1503 {
1504 /* Wrong protocol */
1505 DEBUG(D_receive) debug_printf("Invalid proxy protocol version negotiation\n");
1506 (void) swallow_until_crlf(fd, (uschar*)&hdr, ret, sizeof(hdr)-ret);
1507 goto proxyfail;
1508 }
1509
1510 done:
1511 DEBUG(D_receive)
1512 debug_printf("Valid %s sender from Proxy Protocol header\n", iptype);
1513 yield = proxy_session;
1514
1515 /* Don't flush any potential buffer contents. Any input on proxyfail
1516 should cause a synchronization failure */
1517
1518 proxyfail:
1519 restore_socket_timeout(fd, get_ok, &tvtmp, vslen);
1520
1521 bad:
1522 if (yield)
1523 {
1524 sender_host_name = NULL;
1525 (void) host_name_lookup();
1526 host_build_sender_fullhost();
1527 }
1528 else
1529 {
1530 f.proxy_session_failed = TRUE;
1531 DEBUG(D_receive)
1532 debug_printf("Failure to extract proxied host, only QUIT allowed\n");
1533 }
1534
1535 return;
1536 }
1537 #endif
1538
1539 /*************************************************
1540 * Read one command line *
1541 *************************************************/
1542
1543 /* Strictly, SMTP commands coming over the net are supposed to end with CRLF.
1544 There are sites that don't do this, and in any case internal SMTP probably
1545 should check only for LF. Consequently, we check here for LF only. The line
1546 ends up with [CR]LF removed from its end. If we get an overlong line, treat as
1547 an unknown command. The command is read into the global smtp_cmd_buffer so that
1548 it is available via $smtp_command.
1549
1550 The character reading routine sets up a timeout for each block actually read
1551 from the input (which may contain more than one command). We set up a special
1552 signal handler that closes down the session on a timeout. Control does not
1553 return when it runs.
1554
1555 Arguments:
1556 check_sync if TRUE, check synchronization rules if global option is TRUE
1557 buffer_lim maximum to buffer in lower layer
1558
1559 Returns: a code identifying the command (enumerated above)
1560 */
1561
1562 static int
1563 smtp_read_command(BOOL check_sync, unsigned buffer_lim)
1564 {
1565 int c;
1566 int ptr = 0;
1567 smtp_cmd_list *p;
1568 BOOL hadnull = FALSE;
1569
1570 had_command_timeout = 0;
1571 os_non_restarting_signal(SIGALRM, command_timeout_handler);
1572
1573 while ((c = (receive_getc)(buffer_lim)) != '\n' && c != EOF)
1574 {
1575 if (ptr >= SMTP_CMD_BUFFER_SIZE)
1576 {
1577 os_non_restarting_signal(SIGALRM, sigalrm_handler);
1578 return OTHER_CMD;
1579 }
1580 if (c == 0)
1581 {
1582 hadnull = TRUE;
1583 c = '?';
1584 }
1585 smtp_cmd_buffer[ptr++] = c;
1586 }
1587
1588 receive_linecount++; /* For BSMTP errors */
1589 os_non_restarting_signal(SIGALRM, sigalrm_handler);
1590
1591 /* If hit end of file, return pseudo EOF command. Whether we have a
1592 part-line already read doesn't matter, since this is an error state. */
1593
1594 if (c == EOF) return EOF_CMD;
1595
1596 /* Remove any CR and white space at the end of the line, and terminate the
1597 string. */
1598
1599 while (ptr > 0 && isspace(smtp_cmd_buffer[ptr-1])) ptr--;
1600 smtp_cmd_buffer[ptr] = 0;
1601
1602 DEBUG(D_receive) debug_printf("SMTP<< %s\n", smtp_cmd_buffer);
1603
1604 /* NULLs are not allowed in SMTP commands */
1605
1606 if (hadnull) return BADCHAR_CMD;
1607
1608 /* Scan command list and return identity, having set the data pointer
1609 to the start of the actual data characters. Check for SMTP synchronization
1610 if required. */
1611
1612 for (p = cmd_list; p < cmd_list_end; p++)
1613 {
1614 #ifdef SUPPORT_PROXY
1615 /* Only allow QUIT command if Proxy Protocol parsing failed */
1616 if (proxy_session && f.proxy_session_failed && p->cmd != QUIT_CMD)
1617 continue;
1618 #endif
1619 if ( p->len
1620 && strncmpic(smtp_cmd_buffer, US p->name, p->len) == 0
1621 && ( smtp_cmd_buffer[p->len-1] == ':' /* "mail from:" or "rcpt to:" */
1622 || smtp_cmd_buffer[p->len] == 0
1623 || smtp_cmd_buffer[p->len] == ' '
1624 ) )
1625 {
1626 if (smtp_inptr < smtp_inend && /* Outstanding input */
1627 p->cmd < sync_cmd_limit && /* Command should sync */
1628 check_sync && /* Local flag set */
1629 smtp_enforce_sync && /* Global flag set */
1630 sender_host_address != NULL && /* Not local input */
1631 !f.sender_host_notsocket) /* Really is a socket */
1632 return BADSYN_CMD;
1633
1634 /* The variables $smtp_command and $smtp_command_argument point into the
1635 unmodified input buffer. A copy of the latter is taken for actual
1636 processing, so that it can be chopped up into separate parts if necessary,
1637 for example, when processing a MAIL command options such as SIZE that can
1638 follow the sender address. */
1639
1640 smtp_cmd_argument = smtp_cmd_buffer + p->len;
1641 while (isspace(*smtp_cmd_argument)) smtp_cmd_argument++;
1642 Ustrcpy(smtp_data_buffer, smtp_cmd_argument);
1643 smtp_cmd_data = smtp_data_buffer;
1644
1645 /* Count non-mail commands from those hosts that are controlled in this
1646 way. The default is all hosts. We don't waste effort checking the list
1647 until we get a non-mail command, but then cache the result to save checking
1648 again. If there's a DEFER while checking the host, assume it's in the list.
1649
1650 Note that one instance of RSET, EHLO/HELO, and STARTTLS is allowed at the
1651 start of each incoming message by fiddling with the value in the table. */
1652
1653 if (!p->is_mail_cmd)
1654 {
1655 if (count_nonmail == TRUE_UNSET) count_nonmail =
1656 verify_check_host(&smtp_accept_max_nonmail_hosts) != FAIL;
1657 if (count_nonmail && ++nonmail_command_count > smtp_accept_max_nonmail)
1658 return TOO_MANY_NONMAIL_CMD;
1659 }
1660
1661 /* If there is data for a command that does not expect it, generate the
1662 error here. */
1663
1664 return (p->has_arg || *smtp_cmd_data == 0)? p->cmd : BADARG_CMD;
1665 }
1666 }
1667
1668 #ifdef SUPPORT_PROXY
1669 /* Only allow QUIT command if Proxy Protocol parsing failed */
1670 if (proxy_session && f.proxy_session_failed)
1671 return PROXY_FAIL_IGNORE_CMD;
1672 #endif
1673
1674 /* Enforce synchronization for unknown commands */
1675
1676 if ( smtp_inptr < smtp_inend /* Outstanding input */
1677 && check_sync /* Local flag set */
1678 && smtp_enforce_sync /* Global flag set */
1679 && sender_host_address /* Not local input */
1680 && !f.sender_host_notsocket) /* Really is a socket */
1681 return BADSYN_CMD;
1682
1683 return OTHER_CMD;
1684 }
1685
1686
1687
1688 /*************************************************
1689 * Forced closedown of call *
1690 *************************************************/
1691
1692 /* This function is called from log.c when Exim is dying because of a serious
1693 disaster, and also from some other places. If an incoming non-batched SMTP
1694 channel is open, it swallows the rest of the incoming message if in the DATA
1695 phase, sends the reply string, and gives an error to all subsequent commands
1696 except QUIT. The existence of an SMTP call is detected by the non-NULLness of
1697 smtp_in.
1698
1699 Arguments:
1700 message SMTP reply string to send, excluding the code
1701
1702 Returns: nothing
1703 */
1704
1705 void
1706 smtp_closedown(uschar *message)
1707 {
1708 if (!smtp_in || smtp_batched_input) return;
1709 receive_swallow_smtp();
1710 smtp_printf("421 %s\r\n", FALSE, message);
1711
1712 for (;;) switch(smtp_read_command(FALSE, GETC_BUFFER_UNLIMITED))
1713 {
1714 case EOF_CMD:
1715 return;
1716
1717 case QUIT_CMD:
1718 smtp_printf("221 %s closing connection\r\n", FALSE, smtp_active_hostname);
1719 mac_smtp_fflush();
1720 return;
1721
1722 case RSET_CMD:
1723 smtp_printf("250 Reset OK\r\n", FALSE);
1724 break;
1725
1726 default:
1727 smtp_printf("421 %s\r\n", FALSE, message);
1728 break;
1729 }
1730 }
1731
1732
1733
1734
1735 /*************************************************
1736 * Set up connection info for logging *
1737 *************************************************/
1738
1739 /* This function is called when logging information about an SMTP connection.
1740 It sets up appropriate source information, depending on the type of connection.
1741 If sender_fullhost is NULL, we are at a very early stage of the connection;
1742 just use the IP address.
1743
1744 Argument: none
1745 Returns: a string describing the connection
1746 */
1747
1748 uschar *
1749 smtp_get_connection_info(void)
1750 {
1751 const uschar * hostname = sender_fullhost
1752 ? sender_fullhost : sender_host_address;
1753
1754 if (host_checking)
1755 return string_sprintf("SMTP connection from %s", hostname);
1756
1757 if (f.sender_host_unknown || f.sender_host_notsocket)
1758 return string_sprintf("SMTP connection from %s", sender_ident);
1759
1760 if (f.is_inetd)
1761 return string_sprintf("SMTP connection from %s (via inetd)", hostname);
1762
1763 if (LOGGING(incoming_interface) && interface_address != NULL)
1764 return string_sprintf("SMTP connection from %s I=[%s]:%d", hostname,
1765 interface_address, interface_port);
1766
1767 return string_sprintf("SMTP connection from %s", hostname);
1768 }
1769
1770
1771
1772 #ifdef SUPPORT_TLS
1773 /* Append TLS-related information to a log line
1774
1775 Arguments:
1776 g String under construction: allocated string to extend, or NULL
1777
1778 Returns: Allocated string or NULL
1779 */
1780 static gstring *
1781 s_tlslog(gstring * g)
1782 {
1783 if (LOGGING(tls_cipher) && tls_in.cipher)
1784 g = string_append(g, 2, US" X=", tls_in.cipher);
1785 if (LOGGING(tls_certificate_verified) && tls_in.cipher)
1786 g = string_append(g, 2, US" CV=", tls_in.certificate_verified? "yes":"no");
1787 if (LOGGING(tls_peerdn) && tls_in.peerdn)
1788 g = string_append(g, 3, US" DN=\"", string_printing(tls_in.peerdn), US"\"");
1789 if (LOGGING(tls_sni) && tls_in.sni)
1790 g = string_append(g, 3, US" SNI=\"", string_printing(tls_in.sni), US"\"");
1791 return g;
1792 }
1793 #endif
1794
1795 /*************************************************
1796 * Log lack of MAIL if so configured *
1797 *************************************************/
1798
1799 /* This function is called when an SMTP session ends. If the log selector
1800 smtp_no_mail is set, write a log line giving some details of what has happened
1801 in the SMTP session.
1802
1803 Arguments: none
1804 Returns: nothing
1805 */
1806
1807 void
1808 smtp_log_no_mail(void)
1809 {
1810 int i;
1811 uschar * sep, * s;
1812 gstring * g = NULL;
1813
1814 if (smtp_mailcmd_count > 0 || !LOGGING(smtp_no_mail))
1815 return;
1816
1817 if (sender_host_authenticated)
1818 {
1819 g = string_append(g, 2, US" A=", sender_host_authenticated);
1820 if (authenticated_id) g = string_append(g, 2, US":", authenticated_id);
1821 }
1822
1823 #ifdef SUPPORT_TLS
1824 g = s_tlslog(g);
1825 #endif
1826
1827 sep = smtp_connection_had[SMTP_HBUFF_SIZE-1] != SCH_NONE ? US" C=..." : US" C=";
1828
1829 for (i = smtp_ch_index; i < SMTP_HBUFF_SIZE; i++)
1830 if (smtp_connection_had[i] != SCH_NONE)
1831 {
1832 g = string_append(g, 2, sep, smtp_names[smtp_connection_had[i]]);
1833 sep = US",";
1834 }
1835
1836 for (i = 0; i < smtp_ch_index; i++)
1837 {
1838 g = string_append(g, 2, sep, smtp_names[smtp_connection_had[i]]);
1839 sep = US",";
1840 }
1841
1842 if (!(s = string_from_gstring(g))) s = US"";
1843
1844 log_write(0, LOG_MAIN, "no MAIL in %sSMTP connection from %s D=%s%s",
1845 f.tcp_in_fastopen ? US"TFO " : US"",
1846 host_and_ident(FALSE), string_timesince(&smtp_connection_start), s);
1847 }
1848
1849
1850 /* Return list of recent smtp commands */
1851
1852 uschar *
1853 smtp_cmd_hist(void)
1854 {
1855 int i;
1856 gstring * list = NULL;
1857 uschar * s;
1858
1859 for (i = smtp_ch_index; i < SMTP_HBUFF_SIZE; i++)
1860 if (smtp_connection_had[i] != SCH_NONE)
1861 list = string_append_listele(list, ',', smtp_names[smtp_connection_had[i]]);
1862
1863 for (i = 0; i < smtp_ch_index; i++)
1864 list = string_append_listele(list, ',', smtp_names[smtp_connection_had[i]]);
1865
1866 s = string_from_gstring(list);
1867 return s ? s : US"";
1868 }
1869
1870
1871
1872
1873 /*************************************************
1874 * Check HELO line and set sender_helo_name *
1875 *************************************************/
1876
1877 /* Check the format of a HELO line. The data for HELO/EHLO is supposed to be
1878 the domain name of the sending host, or an ip literal in square brackets. The
1879 argument is placed in sender_helo_name, which is in malloc store, because it
1880 must persist over multiple incoming messages. If helo_accept_junk is set, this
1881 host is permitted to send any old junk (needed for some broken hosts).
1882 Otherwise, helo_allow_chars can be used for rogue characters in general
1883 (typically people want to let in underscores).
1884
1885 Argument:
1886 s the data portion of the line (already past any white space)
1887
1888 Returns: TRUE or FALSE
1889 */
1890
1891 static BOOL
1892 check_helo(uschar *s)
1893 {
1894 uschar *start = s;
1895 uschar *end = s + Ustrlen(s);
1896 BOOL yield = fl.helo_accept_junk;
1897
1898 /* Discard any previous helo name */
1899
1900 if (sender_helo_name)
1901 {
1902 store_free(sender_helo_name);
1903 sender_helo_name = NULL;
1904 }
1905
1906 /* Skip tests if junk is permitted. */
1907
1908 if (!yield)
1909
1910 /* Allow the new standard form for IPv6 address literals, namely,
1911 [IPv6:....], and because someone is bound to use it, allow an equivalent
1912 IPv4 form. Allow plain addresses as well. */
1913
1914 if (*s == '[')
1915 {
1916 if (end[-1] == ']')
1917 {
1918 end[-1] = 0;
1919 if (strncmpic(s, US"[IPv6:", 6) == 0)
1920 yield = (string_is_ip_address(s+6, NULL) == 6);
1921 else if (strncmpic(s, US"[IPv4:", 6) == 0)
1922 yield = (string_is_ip_address(s+6, NULL) == 4);
1923 else
1924 yield = (string_is_ip_address(s+1, NULL) != 0);
1925 end[-1] = ']';
1926 }
1927 }
1928
1929 /* Non-literals must be alpha, dot, hyphen, plus any non-valid chars
1930 that have been configured (usually underscore - sigh). */
1931
1932 else if (*s)
1933 for (yield = TRUE; *s; s++)
1934 if (!isalnum(*s) && *s != '.' && *s != '-' &&
1935 Ustrchr(helo_allow_chars, *s) == NULL)
1936 {
1937 yield = FALSE;
1938 break;
1939 }
1940
1941 /* Save argument if OK */
1942
1943 if (yield) sender_helo_name = string_copy_malloc(start);
1944 return yield;
1945 }
1946
1947
1948
1949
1950
1951 /*************************************************
1952 * Extract SMTP command option *
1953 *************************************************/
1954
1955 /* This function picks the next option setting off the end of smtp_cmd_data. It
1956 is called for MAIL FROM and RCPT TO commands, to pick off the optional ESMTP
1957 things that can appear there.
1958
1959 Arguments:
1960 name point this at the name
1961 value point this at the data string
1962
1963 Returns: TRUE if found an option
1964 */
1965
1966 static BOOL
1967 extract_option(uschar **name, uschar **value)
1968 {
1969 uschar *n;
1970 uschar *v = smtp_cmd_data + Ustrlen(smtp_cmd_data) - 1;
1971 while (isspace(*v)) v--;
1972 v[1] = 0;
1973 while (v > smtp_cmd_data && *v != '=' && !isspace(*v))
1974 {
1975 /* Take care to not stop at a space embedded in a quoted local-part */
1976
1977 if (*v == '"') do v--; while (*v != '"' && v > smtp_cmd_data+1);
1978 v--;
1979 }
1980
1981 n = v;
1982 if (*v == '=')
1983 {
1984 while(isalpha(n[-1])) n--;
1985 /* RFC says SP, but TAB seen in wild and other major MTAs accept it */
1986 if (!isspace(n[-1])) return FALSE;
1987 n[-1] = 0;
1988 }
1989 else
1990 {
1991 n++;
1992 if (v == smtp_cmd_data) return FALSE;
1993 }
1994 *v++ = 0;
1995 *name = n;
1996 *value = v;
1997 return TRUE;
1998 }
1999
2000
2001
2002
2003
2004 /*************************************************
2005 * Reset for new message *
2006 *************************************************/
2007
2008 /* This function is called whenever the SMTP session is reset from
2009 within either of the setup functions; also from the daemon loop.
2010
2011 Argument: the stacking pool storage reset point
2012 Returns: nothing
2013 */
2014
2015 void
2016 smtp_reset(void *reset_point)
2017 {
2018 recipients_list = NULL;
2019 rcpt_count = rcpt_defer_count = rcpt_fail_count =
2020 raw_recipients_count = recipients_count = recipients_list_max = 0;
2021 message_linecount = 0;
2022 message_size = -1;
2023 acl_added_headers = NULL;
2024 acl_removed_headers = NULL;
2025 f.queue_only_policy = FALSE;
2026 rcpt_smtp_response = NULL;
2027 fl.rcpt_smtp_response_same = TRUE;
2028 fl.rcpt_in_progress = FALSE;
2029 f.deliver_freeze = FALSE; /* Can be set by ACL */
2030 freeze_tell = freeze_tell_config; /* Can be set by ACL */
2031 fake_response = OK; /* Can be set by ACL */
2032 #ifdef WITH_CONTENT_SCAN
2033 f.no_mbox_unspool = FALSE; /* Can be set by ACL */
2034 #endif
2035 f.submission_mode = FALSE; /* Can be set by ACL */
2036 f.suppress_local_fixups = f.suppress_local_fixups_default; /* Can be set by ACL */
2037 f.active_local_from_check = local_from_check; /* Can be set by ACL */
2038 f.active_local_sender_retain = local_sender_retain; /* Can be set by ACL */
2039 sending_ip_address = NULL;
2040 return_path = sender_address = NULL;
2041 sender_data = NULL; /* Can be set by ACL */
2042 deliver_localpart_parent = deliver_localpart_orig = NULL;
2043 deliver_domain_parent = deliver_domain_orig = NULL;
2044 callout_address = NULL;
2045 submission_name = NULL; /* Can be set by ACL */
2046 raw_sender = NULL; /* After SMTP rewrite, before qualifying */
2047 sender_address_unrewritten = NULL; /* Set only after verify rewrite */
2048 sender_verified_list = NULL; /* No senders verified */
2049 memset(sender_address_cache, 0, sizeof(sender_address_cache));
2050 memset(sender_domain_cache, 0, sizeof(sender_domain_cache));
2051
2052 authenticated_sender = NULL;
2053 #ifdef EXPERIMENTAL_BRIGHTMAIL
2054 bmi_run = 0;
2055 bmi_verdicts = NULL;
2056 #endif
2057 dnslist_domain = dnslist_matched = NULL;
2058 #ifdef SUPPORT_SPF
2059 spf_header_comment = spf_received = spf_result = spf_smtp_comment = NULL;
2060 spf_result_guessed = FALSE;
2061 #endif
2062 #ifndef DISABLE_DKIM
2063 dkim_cur_signer = dkim_signers =
2064 dkim_signing_domain = dkim_signing_selector = dkim_signatures = NULL;
2065 dkim_cur_signer = dkim_signers = dkim_signing_domain = dkim_signing_selector = NULL;
2066 f.dkim_disable_verify = FALSE;
2067 dkim_collect_input = 0;
2068 dkim_verify_overall = dkim_verify_status = dkim_verify_reason = NULL;
2069 dkim_key_length = 0;
2070 dkim_verify_signers = US"$dkim_signers";
2071 #endif
2072 #ifdef EXPERIMENTAL_DMARC
2073 f.dmarc_has_been_checked = f.dmarc_disable_verify = f.dmarc_enable_forensic = FALSE;
2074 dmarc_domain_policy = dmarc_status = dmarc_status_text =
2075 dmarc_used_domain = NULL;
2076 #endif
2077 #ifdef EXPERIMENTAL_ARC
2078 arc_state = arc_state_reason = NULL;
2079 #endif
2080 dsn_ret = 0;
2081 dsn_envid = NULL;
2082 deliver_host = deliver_host_address = NULL; /* Can be set by ACL */
2083 #ifndef DISABLE_PRDR
2084 prdr_requested = FALSE;
2085 #endif
2086 #ifdef SUPPORT_I18N
2087 message_smtputf8 = FALSE;
2088 #endif
2089 body_linecount = body_zerocount = 0;
2090
2091 sender_rate = sender_rate_limit = sender_rate_period = NULL;
2092 ratelimiters_mail = NULL; /* Updated by ratelimit ACL condition */
2093 /* Note that ratelimiters_conn persists across resets. */
2094
2095 /* Reset message ACL variables */
2096
2097 acl_var_m = NULL;
2098
2099 /* The message body variables use malloc store. They may be set if this is
2100 not the first message in an SMTP session and the previous message caused them
2101 to be referenced in an ACL. */
2102
2103 if (message_body)
2104 {
2105 store_free(message_body);
2106 message_body = NULL;
2107 }
2108
2109 if (message_body_end)
2110 {
2111 store_free(message_body_end);
2112 message_body_end = NULL;
2113 }
2114
2115 /* Warning log messages are also saved in malloc store. They are saved to avoid
2116 repetition in the same message, but it seems right to repeat them for different
2117 messages. */
2118
2119 while (acl_warn_logged)
2120 {
2121 string_item *this = acl_warn_logged;
2122 acl_warn_logged = acl_warn_logged->next;
2123 store_free(this);
2124 }
2125 store_reset(reset_point);
2126 }
2127
2128
2129
2130
2131
2132 /*************************************************
2133 * Initialize for incoming batched SMTP message *
2134 *************************************************/
2135
2136 /* This function is called from smtp_setup_msg() in the case when
2137 smtp_batched_input is true. This happens when -bS is used to pass a whole batch
2138 of messages in one file with SMTP commands between them. All errors must be
2139 reported by sending a message, and only MAIL FROM, RCPT TO, and DATA are
2140 relevant. After an error on a sender, or an invalid recipient, the remainder
2141 of the message is skipped. The value of received_protocol is already set.
2142
2143 Argument: none
2144 Returns: > 0 message successfully started (reached DATA)
2145 = 0 QUIT read or end of file reached
2146 < 0 should not occur
2147 */
2148
2149 static int
2150 smtp_setup_batch_msg(void)
2151 {
2152 int done = 0;
2153 void *reset_point = store_get(0);
2154
2155 /* Save the line count at the start of each transaction - single commands
2156 like HELO and RSET count as whole transactions. */
2157
2158 bsmtp_transaction_linecount = receive_linecount;
2159
2160 if ((receive_feof)()) return 0; /* Treat EOF as QUIT */
2161
2162 cancel_cutthrough_connection(TRUE, US"smtp_setup_batch_msg");
2163 smtp_reset(reset_point); /* Reset for start of message */
2164
2165 /* Deal with SMTP commands. This loop is exited by setting done to a POSITIVE
2166 value. The values are 2 larger than the required yield of the function. */
2167
2168 while (done <= 0)
2169 {
2170 uschar *errmess;
2171 uschar *recipient = NULL;
2172 int start, end, sender_domain, recipient_domain;
2173
2174 switch(smtp_read_command(FALSE, GETC_BUFFER_UNLIMITED))
2175 {
2176 /* The HELO/EHLO commands set sender_address_helo if they have
2177 valid data; otherwise they are ignored, except that they do
2178 a reset of the state. */
2179
2180 case HELO_CMD:
2181 case EHLO_CMD:
2182
2183 check_helo(smtp_cmd_data);
2184 /* Fall through */
2185
2186 case RSET_CMD:
2187 cancel_cutthrough_connection(TRUE, US"RSET received");
2188 smtp_reset(reset_point);
2189 bsmtp_transaction_linecount = receive_linecount;
2190 break;
2191
2192
2193 /* The MAIL FROM command requires an address as an operand. All we
2194 do here is to parse it for syntactic correctness. The form "<>" is
2195 a special case which converts into an empty string. The start/end
2196 pointers in the original are not used further for this address, as
2197 it is the canonical extracted address which is all that is kept. */
2198
2199 case MAIL_CMD:
2200 smtp_mailcmd_count++; /* Count for no-mail log */
2201 if (sender_address != NULL)
2202 /* The function moan_smtp_batch() does not return. */
2203 moan_smtp_batch(smtp_cmd_buffer, "503 Sender already given");
2204
2205 if (smtp_cmd_data[0] == 0)
2206 /* The function moan_smtp_batch() does not return. */
2207 moan_smtp_batch(smtp_cmd_buffer, "501 MAIL FROM must have an address operand");
2208
2209 /* Reset to start of message */
2210
2211 cancel_cutthrough_connection(TRUE, US"MAIL received");
2212 smtp_reset(reset_point);
2213
2214 /* Apply SMTP rewrite */
2215
2216 raw_sender = ((rewrite_existflags & rewrite_smtp) != 0)?
2217 rewrite_one(smtp_cmd_data, rewrite_smtp|rewrite_smtp_sender, NULL, FALSE,
2218 US"", global_rewrite_rules) : smtp_cmd_data;
2219
2220 /* Extract the address; the TRUE flag allows <> as valid */
2221
2222 raw_sender =
2223 parse_extract_address(raw_sender, &errmess, &start, &end, &sender_domain,
2224 TRUE);
2225
2226 if (!raw_sender)
2227 /* The function moan_smtp_batch() does not return. */
2228 moan_smtp_batch(smtp_cmd_buffer, "501 %s", errmess);
2229
2230 sender_address = string_copy(raw_sender);
2231
2232 /* Qualify unqualified sender addresses if permitted to do so. */
2233
2234 if ( !sender_domain
2235 && sender_address[0] != 0 && sender_address[0] != '@')
2236 if (f.allow_unqualified_sender)
2237 {
2238 sender_address = rewrite_address_qualify(sender_address, FALSE);
2239 DEBUG(D_receive) debug_printf("unqualified address %s accepted "
2240 "and rewritten\n", raw_sender);
2241 }
2242 /* The function moan_smtp_batch() does not return. */
2243 else
2244 moan_smtp_batch(smtp_cmd_buffer, "501 sender address must contain "
2245 "a domain");
2246 break;
2247
2248
2249 /* The RCPT TO command requires an address as an operand. All we do
2250 here is to parse it for syntactic correctness. There may be any number
2251 of RCPT TO commands, specifying multiple senders. We build them all into
2252 a data structure that is in argc/argv format. The start/end values
2253 given by parse_extract_address are not used, as we keep only the
2254 extracted address. */
2255
2256 case RCPT_CMD:
2257 if (!sender_address)
2258 /* The function moan_smtp_batch() does not return. */
2259 moan_smtp_batch(smtp_cmd_buffer, "503 No sender yet given");
2260
2261 if (smtp_cmd_data[0] == 0)
2262 /* The function moan_smtp_batch() does not return. */
2263 moan_smtp_batch(smtp_cmd_buffer,
2264 "501 RCPT TO must have an address operand");
2265
2266 /* Check maximum number allowed */
2267
2268 if (recipients_max > 0 && recipients_count + 1 > recipients_max)
2269 /* The function moan_smtp_batch() does not return. */
2270 moan_smtp_batch(smtp_cmd_buffer, "%s too many recipients",
2271 recipients_max_reject? "552": "452");
2272
2273 /* Apply SMTP rewrite, then extract address. Don't allow "<>" as a
2274 recipient address */
2275
2276 recipient = rewrite_existflags & rewrite_smtp
2277 ? rewrite_one(smtp_cmd_data, rewrite_smtp, NULL, FALSE, US"",
2278 global_rewrite_rules)
2279 : smtp_cmd_data;
2280
2281 recipient = parse_extract_address(recipient, &errmess, &start, &end,
2282 &recipient_domain, FALSE);
2283
2284 if (!recipient)
2285 /* The function moan_smtp_batch() does not return. */
2286 moan_smtp_batch(smtp_cmd_buffer, "501 %s", errmess);
2287
2288 /* If the recipient address is unqualified, qualify it if permitted. Then
2289 add it to the list of recipients. */
2290
2291 if (!recipient_domain)
2292 if (f.allow_unqualified_recipient)
2293 {
2294 DEBUG(D_receive) debug_printf("unqualified address %s accepted\n",
2295 recipient);
2296 recipient = rewrite_address_qualify(recipient, TRUE);
2297 }
2298 /* The function moan_smtp_batch() does not return. */
2299 else
2300 moan_smtp_batch(smtp_cmd_buffer,
2301 "501 recipient address must contain a domain");
2302
2303 receive_add_recipient(recipient, -1);
2304 break;
2305
2306
2307 /* The DATA command is legal only if it follows successful MAIL FROM
2308 and RCPT TO commands. This function is complete when a valid DATA
2309 command is encountered. */
2310
2311 case DATA_CMD:
2312 if (!sender_address || recipients_count <= 0)
2313 /* The function moan_smtp_batch() does not return. */
2314 if (!sender_address)
2315 moan_smtp_batch(smtp_cmd_buffer,
2316 "503 MAIL FROM:<sender> command must precede DATA");
2317 else
2318 moan_smtp_batch(smtp_cmd_buffer,
2319 "503 RCPT TO:<recipient> must precede DATA");
2320 else
2321 {
2322 done = 3; /* DATA successfully achieved */
2323 message_ended = END_NOTENDED; /* Indicate in middle of message */
2324 }
2325 break;
2326
2327
2328 /* The VRFY, EXPN, HELP, ETRN, and NOOP commands are ignored. */
2329
2330 case VRFY_CMD:
2331 case EXPN_CMD:
2332 case HELP_CMD:
2333 case NOOP_CMD:
2334 case ETRN_CMD:
2335 bsmtp_transaction_linecount = receive_linecount;
2336 break;
2337
2338
2339 case EOF_CMD:
2340 case QUIT_CMD:
2341 done = 2;
2342 break;
2343
2344
2345 case BADARG_CMD:
2346 /* The function moan_smtp_batch() does not return. */
2347 moan_smtp_batch(smtp_cmd_buffer, "501 Unexpected argument data");
2348 break;
2349
2350
2351 case BADCHAR_CMD:
2352 /* The function moan_smtp_batch() does not return. */
2353 moan_smtp_batch(smtp_cmd_buffer, "501 Unexpected NULL in SMTP command");
2354 break;
2355
2356
2357 default:
2358 /* The function moan_smtp_batch() does not return. */
2359 moan_smtp_batch(smtp_cmd_buffer, "500 Command unrecognized");
2360 break;
2361 }
2362 }
2363
2364 return done - 2; /* Convert yield values */
2365 }
2366
2367
2368
2369
2370 #ifdef SUPPORT_TLS
2371 static BOOL
2372 smtp_log_tls_fail(uschar * errstr)
2373 {
2374 uschar * conn_info = smtp_get_connection_info();
2375
2376 if (Ustrncmp(conn_info, US"SMTP ", 5) == 0) conn_info += 5;
2377 /* I'd like to get separated H= here, but too hard for now */
2378
2379 log_write(0, LOG_MAIN, "TLS error on %s %s", conn_info, errstr);
2380 return FALSE;
2381 }
2382 #endif
2383
2384
2385
2386
2387 #ifdef TCP_FASTOPEN
2388 static void
2389 tfo_in_check(void)
2390 {
2391 # ifdef TCP_INFO
2392 struct tcp_info tinfo;
2393 socklen_t len = sizeof(tinfo);
2394
2395 if ( getsockopt(fileno(smtp_out), IPPROTO_TCP, TCP_INFO, &tinfo, &len) == 0
2396 && tinfo.tcpi_state == TCP_SYN_RECV
2397 )
2398 {
2399 DEBUG(D_receive) debug_printf("TCP_FASTOPEN mode connection (state TCP_SYN_RECV)\n");
2400 f.tcp_in_fastopen = TRUE;
2401 }
2402 # endif
2403 }
2404 #endif
2405
2406
2407 /*************************************************
2408 * Start an SMTP session *
2409 *************************************************/
2410
2411 /* This function is called at the start of an SMTP session. Thereafter,
2412 smtp_setup_msg() is called to initiate each separate message. This
2413 function does host-specific testing, and outputs the banner line.
2414
2415 Arguments: none
2416 Returns: FALSE if the session can not continue; something has
2417 gone wrong, or the connection to the host is blocked
2418 */
2419
2420 BOOL
2421 smtp_start_session(void)
2422 {
2423 int esclen;
2424 uschar *user_msg, *log_msg;
2425 uschar *code, *esc;
2426 uschar *p, *s;
2427 gstring * ss;
2428
2429 gettimeofday(&smtp_connection_start, NULL);
2430 for (smtp_ch_index = 0; smtp_ch_index < SMTP_HBUFF_SIZE; smtp_ch_index++)
2431 smtp_connection_had[smtp_ch_index] = SCH_NONE;
2432 smtp_ch_index = 0;
2433
2434 /* Default values for certain variables */
2435
2436 fl.helo_seen = fl.esmtp = fl.helo_accept_junk = FALSE;
2437 smtp_mailcmd_count = 0;
2438 count_nonmail = TRUE_UNSET;
2439 synprot_error_count = unknown_command_count = nonmail_command_count = 0;
2440 smtp_delay_mail = smtp_rlm_base;
2441 fl.auth_advertised = FALSE;
2442 f.smtp_in_pipelining_advertised = f.smtp_in_pipelining_used = FALSE;
2443 f.pipelining_enable = TRUE;
2444 sync_cmd_limit = NON_SYNC_CMD_NON_PIPELINING;
2445 fl.smtp_exit_function_called = FALSE; /* For avoiding loop in not-quit exit */
2446
2447 /* If receiving by -bs from a trusted user, or testing with -bh, we allow
2448 authentication settings from -oMaa to remain in force. */
2449
2450 if (!host_checking && !f.sender_host_notsocket)
2451 sender_host_auth_pubname = sender_host_authenticated = NULL;
2452 authenticated_by = NULL;
2453
2454 #ifdef SUPPORT_TLS
2455 tls_in.cipher = tls_in.peerdn = NULL;
2456 tls_in.ourcert = tls_in.peercert = NULL;
2457 tls_in.sni = NULL;
2458 tls_in.ocsp = OCSP_NOT_REQ;
2459 fl.tls_advertised = FALSE;
2460 # ifdef EXPERIMENTAL_REQUIRETLS
2461 fl.requiretls_advertised = FALSE;
2462 # endif
2463 #endif
2464 fl.dsn_advertised = FALSE;
2465 #ifdef SUPPORT_I18N
2466 fl.smtputf8_advertised = FALSE;
2467 #endif
2468
2469 /* Reset ACL connection variables */
2470
2471 acl_var_c = NULL;
2472
2473 /* Allow for trailing 0 in the command and data buffers. */
2474
2475 if (!(smtp_cmd_buffer = US malloc(2*SMTP_CMD_BUFFER_SIZE + 2)))
2476 log_write(0, LOG_MAIN|LOG_PANIC_DIE,
2477 "malloc() failed for SMTP command buffer");
2478
2479 smtp_cmd_buffer[0] = 0;
2480 smtp_data_buffer = smtp_cmd_buffer + SMTP_CMD_BUFFER_SIZE + 1;
2481
2482 /* For batched input, the protocol setting can be overridden from the
2483 command line by a trusted caller. */
2484
2485 if (smtp_batched_input)
2486 {
2487 if (!received_protocol) received_protocol = US"local-bsmtp";
2488 }
2489
2490 /* For non-batched SMTP input, the protocol setting is forced here. It will be
2491 reset later if any of EHLO/AUTH/STARTTLS are received. */
2492
2493 else
2494 received_protocol =
2495 (sender_host_address ? protocols : protocols_local) [pnormal];
2496
2497 /* Set up the buffer for inputting using direct read() calls, and arrange to
2498 call the local functions instead of the standard C ones. Place a NUL at the
2499 end of the buffer to safety-stop C-string reads from it. */
2500
2501 if (!(smtp_inbuffer = US malloc(IN_BUFFER_SIZE)))
2502 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "malloc() failed for SMTP input buffer");
2503 smtp_inbuffer[IN_BUFFER_SIZE-1] = '\0';
2504
2505 receive_getc = smtp_getc;
2506 receive_getbuf = smtp_getbuf;
2507 receive_get_cache = smtp_get_cache;
2508 receive_ungetc = smtp_ungetc;
2509 receive_feof = smtp_feof;
2510 receive_ferror = smtp_ferror;
2511 receive_smtp_buffered = smtp_buffered;
2512 smtp_inptr = smtp_inend = smtp_inbuffer;
2513 smtp_had_eof = smtp_had_error = 0;
2514
2515 /* Set up the message size limit; this may be host-specific */
2516
2517 thismessage_size_limit = expand_string_integer(message_size_limit, TRUE);
2518 if (expand_string_message)
2519 {
2520 if (thismessage_size_limit == -1)
2521 log_write(0, LOG_MAIN|LOG_PANIC, "unable to expand message_size_limit: "
2522 "%s", expand_string_message);
2523 else
2524 log_write(0, LOG_MAIN|LOG_PANIC, "invalid message_size_limit: "
2525 "%s", expand_string_message);
2526 smtp_closedown(US"Temporary local problem - please try later");
2527 return FALSE;
2528 }
2529
2530 /* When a message is input locally via the -bs or -bS options, sender_host_
2531 unknown is set unless -oMa was used to force an IP address, in which case it
2532 is checked like a real remote connection. When -bs is used from inetd, this
2533 flag is not set, causing the sending host to be checked. The code that deals
2534 with IP source routing (if configured) is never required for -bs or -bS and
2535 the flag sender_host_notsocket is used to suppress it.
2536
2537 If smtp_accept_max and smtp_accept_reserve are set, keep some connections in
2538 reserve for certain hosts and/or networks. */
2539
2540 if (!f.sender_host_unknown)
2541 {
2542 int rc;
2543 BOOL reserved_host = FALSE;
2544
2545 /* Look up IP options (source routing info) on the socket if this is not an
2546 -oMa "host", and if any are found, log them and drop the connection.
2547
2548 Linux (and others now, see below) is different to everyone else, so there
2549 has to be some conditional compilation here. Versions of Linux before 2.1.15
2550 used a structure whose name was "options". Somebody finally realized that
2551 this name was silly, and it got changed to "ip_options". I use the
2552 newer name here, but there is a fudge in the script that sets up os.h
2553 to define a macro in older Linux systems.
2554
2555 Sigh. Linux is a fast-moving target. Another generation of Linux uses
2556 glibc 2, which has chosen ip_opts for the structure name. This is now
2557 really a glibc thing rather than a Linux thing, so the condition name
2558 has been changed to reflect this. It is relevant also to GNU/Hurd.
2559
2560 Mac OS 10.x (Darwin) is like the later glibc versions, but without the
2561 setting of the __GLIBC__ macro, so we can't detect it automatically. There's
2562 a special macro defined in the os.h file.
2563
2564 Some DGUX versions on older hardware appear not to support IP options at
2565 all, so there is now a general macro which can be set to cut out this
2566 support altogether.
2567
2568 How to do this properly in IPv6 is not yet known. */
2569
2570 #if !HAVE_IPV6 && !defined(NO_IP_OPTIONS)
2571
2572 #ifdef GLIBC_IP_OPTIONS
2573 #if (!defined __GLIBC__) || (__GLIBC__ < 2)
2574 #define OPTSTYLE 1
2575 #else
2576 #define OPTSTYLE 2
2577 #endif
2578 #elif defined DARWIN_IP_OPTIONS
2579 #define OPTSTYLE 2
2580 #else
2581 #define OPTSTYLE 3
2582 #endif
2583
2584 if (!host_checking && !f.sender_host_notsocket)
2585 {
2586 #if OPTSTYLE == 1
2587 EXIM_SOCKLEN_T optlen = sizeof(struct ip_options) + MAX_IPOPTLEN;
2588 struct ip_options *ipopt = store_get(optlen);
2589 #elif OPTSTYLE == 2
2590 struct ip_opts ipoptblock;
2591 struct ip_opts *ipopt = &ipoptblock;
2592 EXIM_SOCKLEN_T optlen = sizeof(ipoptblock);
2593 #else
2594 struct ipoption ipoptblock;
2595 struct ipoption *ipopt = &ipoptblock;
2596 EXIM_SOCKLEN_T optlen = sizeof(ipoptblock);
2597 #endif
2598
2599 /* Occasional genuine failures of getsockopt() have been seen - for
2600 example, "reset by peer". Therefore, just log and give up on this
2601 call, unless the error is ENOPROTOOPT. This error is given by systems
2602 that have the interfaces but not the mechanism - e.g. GNU/Hurd at the time
2603 of writing. So for that error, carry on - we just can't do an IP options
2604 check. */
2605
2606 DEBUG(D_receive) debug_printf("checking for IP options\n");
2607
2608 if (getsockopt(fileno(smtp_out), IPPROTO_IP, IP_OPTIONS, US (ipopt),
2609 &optlen) < 0)
2610 {
2611 if (errno != ENOPROTOOPT)
2612 {
2613 log_write(0, LOG_MAIN, "getsockopt() failed from %s: %s",
2614 host_and_ident(FALSE), strerror(errno));
2615 smtp_printf("451 SMTP service not available\r\n", FALSE);
2616 return FALSE;
2617 }
2618 }
2619
2620 /* Deal with any IP options that are set. On the systems I have looked at,
2621 the value of MAX_IPOPTLEN has been 40, meaning that there should never be
2622 more logging data than will fit in big_buffer. Nevertheless, after somebody
2623 questioned this code, I've added in some paranoid checking. */
2624
2625 else if (optlen > 0)
2626 {
2627 uschar *p = big_buffer;
2628 uschar *pend = big_buffer + big_buffer_size;
2629 uschar *opt, *adptr;
2630 int optcount;
2631 struct in_addr addr;
2632
2633 #if OPTSTYLE == 1
2634 uschar *optstart = US (ipopt->__data);
2635 #elif OPTSTYLE == 2
2636 uschar *optstart = US (ipopt->ip_opts);
2637 #else
2638 uschar *optstart = US (ipopt->ipopt_list);
2639 #endif
2640
2641 DEBUG(D_receive) debug_printf("IP options exist\n");
2642
2643 Ustrcpy(p, "IP options on incoming call:");
2644 p += Ustrlen(p);
2645
2646 for (opt = optstart; opt != NULL &&
2647 opt < US (ipopt) + optlen;)
2648 {
2649 switch (*opt)
2650 {
2651 case IPOPT_EOL:
2652 opt = NULL;
2653 break;
2654
2655 case IPOPT_NOP:
2656 opt++;
2657 break;
2658
2659 case IPOPT_SSRR:
2660 case IPOPT_LSRR:
2661 if (!string_format(p, pend-p, " %s [@%s",
2662 (*opt == IPOPT_SSRR)? "SSRR" : "LSRR",
2663 #if OPTSTYLE == 1
2664 inet_ntoa(*((struct in_addr *)(&(ipopt->faddr))))))
2665 #elif OPTSTYLE == 2
2666 inet_ntoa(ipopt->ip_dst)))
2667 #else
2668 inet_ntoa(ipopt->ipopt_dst)))
2669 #endif
2670 {
2671 opt = NULL;
2672 break;
2673 }
2674
2675 p += Ustrlen(p);
2676 optcount = (opt[1] - 3) / sizeof(struct in_addr);
2677 adptr = opt + 3;
2678 while (optcount-- > 0)
2679 {
2680 memcpy(&addr, adptr, sizeof(addr));
2681 if (!string_format(p, pend - p - 1, "%s%s",
2682 (optcount == 0)? ":" : "@", inet_ntoa(addr)))
2683 {
2684 opt = NULL;
2685 break;
2686 }
2687 p += Ustrlen(p);
2688 adptr += sizeof(struct in_addr);
2689 }
2690 *p++ = ']';
2691 opt += opt[1];
2692 break;
2693
2694 default:
2695 {
2696 int i;
2697 if (pend - p < 4 + 3*opt[1]) { opt = NULL; break; }
2698 Ustrcat(p, "[ ");
2699 p += 2;
2700 for (i = 0; i < opt[1]; i++)
2701 p += sprintf(CS p, "%2.2x ", opt[i]);
2702 *p++ = ']';
2703 }
2704 opt += opt[1];
2705 break;
2706 }
2707 }
2708
2709 *p = 0;
2710 log_write(0, LOG_MAIN, "%s", big_buffer);
2711
2712 /* Refuse any call with IP options. This is what tcpwrappers 7.5 does. */
2713
2714 log_write(0, LOG_MAIN|LOG_REJECT,
2715 "connection from %s refused (IP options)", host_and_ident(FALSE));
2716
2717 smtp_printf("554 SMTP service not available\r\n", FALSE);
2718 return FALSE;
2719 }
2720
2721 /* Length of options = 0 => there are no options */
2722
2723 else DEBUG(D_receive) debug_printf("no IP options found\n");
2724 }
2725 #endif /* HAVE_IPV6 && !defined(NO_IP_OPTIONS) */
2726
2727 /* Set keep-alive in socket options. The option is on by default. This
2728 setting is an attempt to get rid of some hanging connections that stick in
2729 read() when the remote end (usually a dialup) goes away. */
2730
2731 if (smtp_accept_keepalive && !f.sender_host_notsocket)
2732 ip_keepalive(fileno(smtp_out), sender_host_address, FALSE);
2733
2734 /* If the current host matches host_lookup, set the name by doing a
2735 reverse lookup. On failure, sender_host_name will be NULL and
2736 host_lookup_failed will be TRUE. This may or may not be serious - optional
2737 checks later. */
2738
2739 if (verify_check_host(&host_lookup) == OK)
2740 {
2741 (void)host_name_lookup();
2742 host_build_sender_fullhost();
2743 }
2744
2745 /* Delay this until we have the full name, if it is looked up. */
2746
2747 set_process_info("handling incoming connection from %s",
2748 host_and_ident(FALSE));
2749
2750 /* Expand smtp_receive_timeout, if needed */
2751
2752 if (smtp_receive_timeout_s)
2753 {
2754 uschar * exp;
2755 if ( !(exp = expand_string(smtp_receive_timeout_s))
2756 || !(*exp)
2757 || (smtp_receive_timeout = readconf_readtime(exp, 0, FALSE)) < 0
2758 )
2759 log_write(0, LOG_MAIN|LOG_PANIC,
2760 "bad value for smtp_receive_timeout: '%s'", exp ? exp : US"");
2761 }
2762
2763 /* Test for explicit connection rejection */
2764
2765 if (verify_check_host(&host_reject_connection) == OK)
2766 {
2767 log_write(L_connection_reject, LOG_MAIN|LOG_REJECT, "refused connection "
2768 "from %s (host_reject_connection)", host_and_ident(FALSE));
2769 smtp_printf("554 SMTP service not available\r\n", FALSE);
2770 return FALSE;
2771 }
2772
2773 /* Test with TCP Wrappers if so configured. There is a problem in that
2774 hosts_ctl() returns 0 (deny) under a number of system failure circumstances,
2775 such as disks dying. In these cases, it is desirable to reject with a 4xx
2776 error instead of a 5xx error. There isn't a "right" way to detect such
2777 problems. The following kludge is used: errno is zeroed before calling
2778 hosts_ctl(). If the result is "reject", a 5xx error is given only if the
2779 value of errno is 0 or ENOENT (which happens if /etc/hosts.{allow,deny} does
2780 not exist). */
2781
2782 #ifdef USE_TCP_WRAPPERS
2783 errno = 0;
2784 if (!(tcp_wrappers_name = expand_string(tcp_wrappers_daemon_name)))
2785 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "Expansion of \"%s\" "
2786 "(tcp_wrappers_name) failed: %s", string_printing(tcp_wrappers_name),
2787 expand_string_message);
2788
2789 if (!hosts_ctl(tcp_wrappers_name,
2790 sender_host_name ? CS sender_host_name : STRING_UNKNOWN,
2791 sender_host_address ? CS sender_host_address : STRING_UNKNOWN,
2792 sender_ident ? CS sender_ident : STRING_UNKNOWN))
2793 {
2794 if (errno == 0 || errno == ENOENT)
2795 {
2796 HDEBUG(D_receive) debug_printf("tcp wrappers rejection\n");
2797 log_write(L_connection_reject,
2798 LOG_MAIN|LOG_REJECT, "refused connection from %s "
2799 "(tcp wrappers)", host_and_ident(FALSE));
2800 smtp_printf("554 SMTP service not available\r\n", FALSE);
2801 }
2802 else
2803 {
2804 int save_errno = errno;
2805 HDEBUG(D_receive) debug_printf("tcp wrappers rejected with unexpected "
2806 "errno value %d\n", save_errno);
2807 log_write(L_connection_reject,
2808 LOG_MAIN|LOG_REJECT, "temporarily refused connection from %s "
2809 "(tcp wrappers errno=%d)", host_and_ident(FALSE), save_errno);
2810 smtp_printf("451 Temporary local problem - please try later\r\n", FALSE);
2811 }
2812 return FALSE;
2813 }
2814 #endif
2815
2816 /* Check for reserved slots. The value of smtp_accept_count has already been
2817 incremented to include this process. */
2818
2819 if (smtp_accept_max > 0 &&
2820 smtp_accept_count > smtp_accept_max - smtp_accept_reserve)
2821 {
2822 if ((rc = verify_check_host(&smtp_reserve_hosts)) != OK)
2823 {
2824 log_write(L_connection_reject,
2825 LOG_MAIN, "temporarily refused connection from %s: not in "
2826 "reserve list: connected=%d max=%d reserve=%d%s",
2827 host_and_ident(FALSE), smtp_accept_count - 1, smtp_accept_max,
2828 smtp_accept_reserve, (rc == DEFER)? " (lookup deferred)" : "");
2829 smtp_printf("421 %s: Too many concurrent SMTP connections; "
2830 "please try again later\r\n", FALSE, smtp_active_hostname);
2831 return FALSE;
2832 }
2833 reserved_host = TRUE;
2834 }
2835
2836 /* If a load level above which only messages from reserved hosts are
2837 accepted is set, check the load. For incoming calls via the daemon, the
2838 check is done in the superior process if there are no reserved hosts, to
2839 save a fork. In all cases, the load average will already be available
2840 in a global variable at this point. */
2841
2842 if (smtp_load_reserve >= 0 &&
2843 load_average > smtp_load_reserve &&
2844 !reserved_host &&
2845 verify_check_host(&smtp_reserve_hosts) != OK)
2846 {
2847 log_write(L_connection_reject,
2848 LOG_MAIN, "temporarily refused connection from %s: not in "
2849 "reserve list and load average = %.2f", host_and_ident(FALSE),
2850 (double)load_average/1000.0);
2851 smtp_printf("421 %s: Too much load; please try again later\r\n", FALSE,
2852 smtp_active_hostname);
2853 return FALSE;
2854 }
2855
2856 /* Determine whether unqualified senders or recipients are permitted
2857 for this host. Unfortunately, we have to do this every time, in order to
2858 set the flags so that they can be inspected when considering qualifying
2859 addresses in the headers. For a site that permits no qualification, this
2860 won't take long, however. */
2861
2862 f.allow_unqualified_sender =
2863 verify_check_host(&sender_unqualified_hosts) == OK;
2864
2865 f.allow_unqualified_recipient =
2866 verify_check_host(&recipient_unqualified_hosts) == OK;
2867
2868 /* Determine whether HELO/EHLO is required for this host. The requirement
2869 can be hard or soft. */
2870
2871 fl.helo_required = verify_check_host(&helo_verify_hosts) == OK;
2872 if (!fl.helo_required)
2873 fl.helo_verify = verify_check_host(&helo_try_verify_hosts) == OK;
2874
2875 /* Determine whether this hosts is permitted to send syntactic junk
2876 after a HELO or EHLO command. */
2877
2878 fl.helo_accept_junk = verify_check_host(&helo_accept_junk_hosts) == OK;
2879 }
2880
2881 /* For batch SMTP input we are now done. */
2882
2883 if (smtp_batched_input) return TRUE;
2884
2885 /* If valid Proxy Protocol source is connecting, set up session.
2886 * Failure will not allow any SMTP function other than QUIT. */
2887
2888 #ifdef SUPPORT_PROXY
2889 proxy_session = FALSE;
2890 f.proxy_session_failed = FALSE;
2891 if (check_proxy_protocol_host())
2892 setup_proxy_protocol_host();
2893 #endif
2894
2895 /* Start up TLS if tls_on_connect is set. This is for supporting the legacy
2896 smtps port for use with older style SSL MTAs. */
2897
2898 #ifdef SUPPORT_TLS
2899 if (tls_in.on_connect)
2900 {
2901 if (tls_server_start(tls_require_ciphers, &user_msg) != OK)
2902 return smtp_log_tls_fail(user_msg);
2903 cmd_list[CMD_LIST_TLS_AUTH].is_mail_cmd = TRUE;
2904 }
2905 #endif
2906
2907 /* Run the connect ACL if it exists */
2908
2909 user_msg = NULL;
2910 if (acl_smtp_connect)
2911 {
2912 int rc;
2913 if ((rc = acl_check(ACL_WHERE_CONNECT, NULL, acl_smtp_connect, &user_msg,
2914 &log_msg)) != OK)
2915 {
2916 (void) smtp_handle_acl_fail(ACL_WHERE_CONNECT, rc, user_msg, log_msg);
2917 return FALSE;
2918 }
2919 }
2920
2921 /* Output the initial message for a two-way SMTP connection. It may contain
2922 newlines, which then cause a multi-line response to be given. */
2923
2924 code = US"220"; /* Default status code */
2925 esc = US""; /* Default extended status code */
2926 esclen = 0; /* Length of esc */
2927
2928 if (!user_msg)
2929 {
2930 if (!(s = expand_string(smtp_banner)))
2931 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "Expansion of \"%s\" (smtp_banner) "
2932 "failed: %s", smtp_banner, expand_string_message);
2933 }
2934 else
2935 {
2936 int codelen = 3;
2937 s = user_msg;
2938 smtp_message_code(&code, &codelen, &s, NULL, TRUE);
2939 if (codelen > 4)
2940 {
2941 esc = code + 4;
2942 esclen = codelen - 4;
2943 }
2944 }
2945
2946 /* Remove any terminating newlines; might as well remove trailing space too */
2947
2948 p = s + Ustrlen(s);
2949 while (p > s && isspace(p[-1])) p--;
2950 *p = 0;
2951
2952 /* It seems that CC:Mail is braindead, and assumes that the greeting message
2953 is all contained in a single IP packet. The original code wrote out the
2954 greeting using several calls to fprint/fputc, and on busy servers this could
2955 cause it to be split over more than one packet - which caused CC:Mail to fall
2956 over when it got the second part of the greeting after sending its first
2957 command. Sigh. To try to avoid this, build the complete greeting message
2958 first, and output it in one fell swoop. This gives a better chance of it
2959 ending up as a single packet. */
2960
2961 ss = string_get(256);
2962
2963 p = s;
2964 do /* At least once, in case we have an empty string */
2965 {
2966 int len;
2967 uschar *linebreak = Ustrchr(p, '\n');
2968 ss = string_catn(ss, code, 3);
2969 if (!linebreak)
2970 {
2971 len = Ustrlen(p);
2972 ss = string_catn(ss, US" ", 1);
2973 }
2974 else
2975 {
2976 len = linebreak - p;
2977 ss = string_catn(ss, US"-", 1);
2978 }
2979 ss = string_catn(ss, esc, esclen);
2980 ss = string_catn(ss, p, len);
2981 ss = string_catn(ss, US"\r\n", 2);
2982 p += len;
2983 if (linebreak) p++;
2984 }
2985 while (*p);
2986
2987 /* Before we write the banner, check that there is no input pending, unless
2988 this synchronisation check is disabled. */
2989
2990 if (!check_sync())
2991 {
2992 unsigned n = smtp_inend - smtp_inptr;
2993 if (n > 32) n = 32;
2994
2995 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP protocol "
2996 "synchronization error (input sent without waiting for greeting): "
2997 "rejected connection from %s input=\"%s\"", host_and_ident(TRUE),
2998 string_printing(string_copyn(smtp_inptr, n)));
2999 smtp_printf("554 SMTP synchronization error\r\n", FALSE);
3000 return FALSE;
3001 }
3002
3003 /* Now output the banner */
3004
3005 smtp_printf("%s", FALSE, string_from_gstring(ss));
3006
3007 /* Attempt to see if we sent the banner before the last ACK of the 3-way
3008 handshake arrived. If so we must have managed a TFO. */
3009
3010 #ifdef TCP_FASTOPEN
3011 tfo_in_check();
3012 #endif
3013
3014 return TRUE;
3015 }
3016
3017
3018
3019
3020
3021 /*************************************************
3022 * Handle SMTP syntax and protocol errors *
3023 *************************************************/
3024
3025 /* Write to the log for SMTP syntax errors in incoming commands, if configured
3026 to do so. Then transmit the error response. The return value depends on the
3027 number of syntax and protocol errors in this SMTP session.
3028
3029 Arguments:
3030 type error type, given as a log flag bit
3031 code response code; <= 0 means don't send a response
3032 data data to reflect in the response (can be NULL)
3033 errmess the error message
3034
3035 Returns: -1 limit of syntax/protocol errors NOT exceeded
3036 +1 limit of syntax/protocol errors IS exceeded
3037
3038 These values fit in with the values of the "done" variable in the main
3039 processing loop in smtp_setup_msg(). */
3040
3041 static int
3042 synprot_error(int type, int code, uschar *data, uschar *errmess)
3043 {
3044 int yield = -1;
3045
3046 log_write(type, LOG_MAIN, "SMTP %s error in \"%s\" %s %s",
3047 (type == L_smtp_syntax_error)? "syntax" : "protocol",
3048 string_printing(smtp_cmd_buffer), host_and_ident(TRUE), errmess);
3049
3050 if (++synprot_error_count > smtp_max_synprot_errors)
3051 {
3052 yield = 1;
3053 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
3054 "syntax or protocol errors (last command was \"%s\")",
3055 host_and_ident(FALSE), string_printing(smtp_cmd_buffer));
3056 }
3057
3058 if (code > 0)
3059 {
3060 smtp_printf("%d%c%s%s%s\r\n", FALSE, code, yield == 1 ? '-' : ' ',
3061 data ? data : US"", data ? US": " : US"", errmess);
3062 if (yield == 1)
3063 smtp_printf("%d Too many syntax or protocol errors\r\n", FALSE, code);
3064 }
3065
3066 return yield;
3067 }
3068
3069
3070
3071
3072 /*************************************************
3073 * Send SMTP response, possibly multiline *
3074 *************************************************/
3075
3076 /* There are, it seems, broken clients out there that cannot handle multiline
3077 responses. If no_multiline_responses is TRUE (it can be set from an ACL), we
3078 output nothing for non-final calls, and only the first line for anything else.
3079
3080 Arguments:
3081 code SMTP code, may involve extended status codes
3082 codelen length of smtp code; if > 4 there's an ESC
3083 final FALSE if the last line isn't the final line
3084 msg message text, possibly containing newlines
3085
3086 Returns: nothing
3087 */
3088
3089 void
3090 smtp_respond(uschar* code, int codelen, BOOL final, uschar *msg)
3091 {
3092 int esclen = 0;
3093 uschar *esc = US"";
3094
3095 if (!final && f.no_multiline_responses) return;
3096
3097 if (codelen > 4)
3098 {
3099 esc = code + 4;
3100 esclen = codelen - 4;
3101 }
3102
3103 /* If this is the first output for a (non-batch) RCPT command, see if all RCPTs
3104 have had the same. Note: this code is also present in smtp_printf(). It would
3105 be tidier to have it only in one place, but when it was added, it was easier to
3106 do it that way, so as not to have to mess with the code for the RCPT command,
3107 which sometimes uses smtp_printf() and sometimes smtp_respond(). */
3108
3109 if (fl.rcpt_in_progress)
3110 {
3111 if (rcpt_smtp_response == NULL)
3112 rcpt_smtp_response = string_copy(msg);
3113 else if (fl.rcpt_smtp_response_same &&
3114 Ustrcmp(rcpt_smtp_response, msg) != 0)
3115 fl.rcpt_smtp_response_same = FALSE;
3116 fl.rcpt_in_progress = FALSE;
3117 }
3118
3119 /* Now output the message, splitting it up into multiple lines if necessary.
3120 We only handle pipelining these responses as far as nonfinal/final groups,
3121 not the whole MAIL/RCPT/DATA response set. */
3122
3123 for (;;)
3124 {
3125 uschar *nl = Ustrchr(msg, '\n');
3126 if (nl == NULL)
3127 {
3128 smtp_printf("%.3s%c%.*s%s\r\n", !final, code, final ? ' ':'-', esclen, esc, msg);
3129 return;
3130 }
3131 else if (nl[1] == 0 || f.no_multiline_responses)
3132 {
3133 smtp_printf("%.3s%c%.*s%.*s\r\n", !final, code, final ? ' ':'-', esclen, esc,
3134 (int)(nl - msg), msg);
3135 return;
3136 }
3137 else
3138 {
3139 smtp_printf("%.3s-%.*s%.*s\r\n", TRUE, code, esclen, esc, (int)(nl - msg), msg);
3140 msg = nl + 1;
3141 while (isspace(*msg)) msg++;
3142 }
3143 }
3144 }
3145
3146
3147
3148
3149 /*************************************************
3150 * Parse user SMTP message *
3151 *************************************************/
3152
3153 /* This function allows for user messages overriding the response code details
3154 by providing a suitable response code string at the start of the message
3155 user_msg. Check the message for starting with a response code and optionally an
3156 extended status code. If found, check that the first digit is valid, and if so,
3157 change the code pointer and length to use the replacement. An invalid code
3158 causes a panic log; in this case, if the log messages is the same as the user
3159 message, we must also adjust the value of the log message to show the code that
3160 is actually going to be used (the original one).
3161
3162 This function is global because it is called from receive.c as well as within
3163 this module.
3164
3165 Note that the code length returned includes the terminating whitespace
3166 character, which is always included in the regex match.
3167
3168 Arguments:
3169 code SMTP code, may involve extended status codes
3170 codelen length of smtp code; if > 4 there's an ESC
3171 msg message text
3172 log_msg optional log message, to be adjusted with the new SMTP code
3173 check_valid if true, verify the response code
3174
3175 Returns: nothing
3176 */
3177
3178 void
3179 smtp_message_code(uschar **code, int *codelen, uschar **msg, uschar **log_msg,
3180 BOOL check_valid)
3181 {
3182 int n;
3183 int ovector[3];
3184
3185 if (!msg || !*msg) return;
3186
3187 if ((n = pcre_exec(regex_smtp_code, NULL, CS *msg, Ustrlen(*msg), 0,
3188 PCRE_EOPT, ovector, sizeof(ovector)/sizeof(int))) < 0) return;
3189
3190 if (check_valid && (*msg)[0] != (*code)[0])
3191 {
3192 log_write(0, LOG_MAIN|LOG_PANIC, "configured error code starts with "
3193 "incorrect digit (expected %c) in \"%s\"", (*code)[0], *msg);
3194 if (log_msg != NULL && *log_msg == *msg)
3195 *log_msg = string_sprintf("%s %s", *code, *log_msg + ovector[1]);
3196 }
3197 else
3198 {
3199 *code = *msg;
3200 *codelen = ovector[1]; /* Includes final space */
3201 }
3202 *msg += ovector[1]; /* Chop the code off the message */
3203 return;
3204 }
3205
3206
3207
3208
3209 /*************************************************
3210 * Handle an ACL failure *
3211 *************************************************/
3212
3213 /* This function is called when acl_check() fails. As well as calls from within
3214 this module, it is called from receive.c for an ACL after DATA. It sorts out
3215 logging the incident, and sends the error response. A message containing
3216 newlines is turned into a multiline SMTP response, but for logging, only the
3217 first line is used.
3218
3219 There's a table of default permanent failure response codes to use in
3220 globals.c, along with the table of names. VFRY is special. Despite RFC1123 it
3221 defaults disabled in Exim. However, discussion in connection with RFC 821bis
3222 (aka RFC 2821) has concluded that the response should be 252 in the disabled
3223 state, because there are broken clients that try VRFY before RCPT. A 5xx
3224 response should be given only when the address is positively known to be
3225 undeliverable. Sigh. We return 252 if there is no VRFY ACL or it provides
3226 no explicit code, but if there is one we let it know best.
3227 Also, for ETRN, 458 is given on refusal, and for AUTH, 503.
3228
3229 From Exim 4.63, it is possible to override the response code details by
3230 providing a suitable response code string at the start of the message provided
3231 in user_msg. The code's first digit is checked for validity.
3232
3233 Arguments:
3234 where where the ACL was called from
3235 rc the failure code
3236 user_msg a message that can be included in an SMTP response
3237 log_msg a message for logging
3238
3239 Returns: 0 in most cases
3240 2 if the failure code was FAIL_DROP, in which case the
3241 SMTP connection should be dropped (this value fits with the
3242 "done" variable in smtp_setup_msg() below)
3243 */
3244
3245 int
3246 smtp_handle_acl_fail(int where, int rc, uschar *user_msg, uschar *log_msg)
3247 {
3248 BOOL drop = rc == FAIL_DROP;
3249 int codelen = 3;
3250 uschar *smtp_code;
3251 uschar *lognl;
3252 uschar *sender_info = US"";
3253 uschar *what =
3254 #ifdef WITH_CONTENT_SCAN
3255 where == ACL_WHERE_MIME ? US"during MIME ACL checks" :
3256 #endif
3257 where == ACL_WHERE_PREDATA ? US"DATA" :
3258 where == ACL_WHERE_DATA ? US"after DATA" :
3259 #ifndef DISABLE_PRDR
3260 where == ACL_WHERE_PRDR ? US"after DATA PRDR" :
3261 #endif
3262 smtp_cmd_data ?
3263 string_sprintf("%s %s", acl_wherenames[where], smtp_cmd_data) :
3264 string_sprintf("%s in \"connect\" ACL", acl_wherenames[where]);
3265
3266 if (drop) rc = FAIL;
3267
3268 /* Set the default SMTP code, and allow a user message to change it. */
3269
3270 smtp_code = rc == FAIL ? acl_wherecodes[where] : US"451";
3271 smtp_message_code(&smtp_code, &codelen, &user_msg, &log_msg,
3272 where != ACL_WHERE_VRFY);
3273
3274 /* We used to have sender_address here; however, there was a bug that was not
3275 updating sender_address after a rewrite during a verify. When this bug was
3276 fixed, sender_address at this point became the rewritten address. I'm not sure
3277 this is what should be logged, so I've changed to logging the unrewritten
3278 address to retain backward compatibility. */
3279
3280 #ifndef WITH_CONTENT_SCAN
3281 if (where == ACL_WHERE_RCPT || where == ACL_WHERE_DATA)
3282 #else
3283 if (where == ACL_WHERE_RCPT || where == ACL_WHERE_DATA || where == ACL_WHERE_MIME)
3284 #endif
3285 {
3286 sender_info = string_sprintf("F=<%s>%s%s%s%s ",
3287 sender_address_unrewritten ? sender_address_unrewritten : sender_address,
3288 sender_host_authenticated ? US" A=" : US"",
3289 sender_host_authenticated ? sender_host_authenticated : US"",
3290 sender_host_authenticated && authenticated_id ? US":" : US"",
3291 sender_host_authenticated && authenticated_id ? authenticated_id : US""
3292 );
3293 }
3294
3295 /* If there's been a sender verification failure with a specific message, and
3296 we have not sent a response about it yet, do so now, as a preliminary line for
3297 failures, but not defers. However, always log it for defer, and log it for fail
3298 unless the sender_verify_fail log selector has been turned off. */
3299
3300 if (sender_verified_failed &&
3301 !testflag(sender_verified_failed, af_sverify_told))
3302 {
3303 BOOL save_rcpt_in_progress = fl.rcpt_in_progress;
3304 fl.rcpt_in_progress = FALSE; /* So as not to treat these as the error */
3305
3306 setflag(sender_verified_failed, af_sverify_told);
3307
3308 if (rc != FAIL || LOGGING(sender_verify_fail))
3309 log_write(0, LOG_MAIN|LOG_REJECT, "%s sender verify %s for <%s>%s",
3310 host_and_ident(TRUE),
3311 ((sender_verified_failed->special_action & 255) == DEFER)? "defer":"fail",
3312 sender_verified_failed->address,
3313 (sender_verified_failed->message == NULL)? US"" :
3314 string_sprintf(": %s", sender_verified_failed->message));
3315
3316 if (rc == FAIL && sender_verified_failed->user_message)
3317 smtp_respond(smtp_code, codelen, FALSE, string_sprintf(
3318 testflag(sender_verified_failed, af_verify_pmfail)?
3319 "Postmaster verification failed while checking <%s>\n%s\n"
3320 "Several RFCs state that you are required to have a postmaster\n"
3321 "mailbox for each mail domain. This host does not accept mail\n"
3322 "from domains whose servers reject the postmaster address."
3323 :
3324 testflag(sender_verified_failed, af_verify_nsfail)?
3325 "Callback setup failed while verifying <%s>\n%s\n"
3326 "The initial connection, or a HELO or MAIL FROM:<> command was\n"
3327 "rejected. Refusing MAIL FROM:<> does not help fight spam, disregards\n"
3328 "RFC requirements, and stops you from receiving standard bounce\n"
3329 "messages. This host does not accept mail from domains whose servers\n"
3330 "refuse bounces."
3331 :
3332 "Verification failed for <%s>\n%s",
3333 sender_verified_failed->address,
3334 sender_verified_failed->user_message));
3335
3336 fl.rcpt_in_progress = save_rcpt_in_progress;
3337 }
3338
3339 /* Sort out text for logging */
3340
3341 log_msg = log_msg ? string_sprintf(": %s", log_msg) : US"";
3342 if ((lognl = Ustrchr(log_msg, '\n'))) *lognl = 0;
3343
3344 /* Send permanent failure response to the command, but the code used isn't
3345 always a 5xx one - see comments at the start of this function. If the original
3346 rc was FAIL_DROP we drop the connection and yield 2. */
3347
3348 if (rc == FAIL)
3349 smtp_respond(smtp_code, codelen, TRUE,
3350 user_msg ? user_msg : US"Administrative prohibition");
3351
3352 /* Send temporary failure response to the command. Don't give any details,
3353 unless acl_temp_details is set. This is TRUE for a callout defer, a "defer"
3354 verb, and for a header verify when smtp_return_error_details is set.
3355
3356 This conditional logic is all somewhat of a mess because of the odd
3357 interactions between temp_details and return_error_details. One day it should
3358 be re-implemented in a tidier fashion. */
3359
3360 else
3361 if (f.acl_temp_details && user_msg)
3362 {
3363 if ( smtp_return_error_details
3364 && sender_verified_failed
3365 && sender_verified_failed->message
3366 )
3367 smtp_respond(smtp_code, codelen, FALSE, sender_verified_failed->message);
3368
3369 smtp_respond(smtp_code, codelen, TRUE, user_msg);
3370 }
3371 else
3372 smtp_respond(smtp_code, codelen, TRUE,
3373 US"Temporary local problem - please try later");
3374
3375 /* Log the incident to the logs that are specified by log_reject_target
3376 (default main, reject). This can be empty to suppress logging of rejections. If
3377 the connection is not forcibly to be dropped, return 0. Otherwise, log why it
3378 is closing if required and return 2. */
3379
3380 if (log_reject_target != 0)
3381 {
3382 #ifdef SUPPORT_TLS
3383 gstring * g = s_tlslog(NULL);
3384 uschar * tls = string_from_gstring(g);
3385 if (!tls) tls = US"";
3386 #else
3387 uschar * tls = US"";
3388 #endif
3389 log_write(where == ACL_WHERE_CONNECT ? L_connection_reject : 0,
3390 log_reject_target, "%s%s%s %s%srejected %s%s",
3391 LOGGING(dnssec) && sender_host_dnssec ? US" DS" : US"",
3392 host_and_ident(TRUE),
3393 tls,
3394 sender_info,
3395 rc == FAIL ? US"" : US"temporarily ",
3396 what, log_msg);
3397 }
3398
3399 if (!drop) return 0;
3400
3401 log_write(L_smtp_connection, LOG_MAIN, "%s closed by DROP in ACL",
3402 smtp_get_connection_info());
3403
3404 /* Run the not-quit ACL, but without any custom messages. This should not be a
3405 problem, because we get here only if some other ACL has issued "drop", and
3406 in that case, *its* custom messages will have been used above. */
3407
3408 smtp_notquit_exit(US"acl-drop", NULL, NULL);
3409 return 2;
3410 }
3411
3412
3413
3414
3415 /*************************************************
3416 * Handle SMTP exit when QUIT is not given *
3417 *************************************************/
3418
3419 /* This function provides a logging/statistics hook for when an SMTP connection
3420 is dropped on the floor or the other end goes away. It's a global function
3421 because it's called from receive.c as well as this module. As well as running
3422 the NOTQUIT ACL, if there is one, this function also outputs a final SMTP
3423 response, either with a custom message from the ACL, or using a default. There
3424 is one case, however, when no message is output - after "drop". In that case,
3425 the ACL that obeyed "drop" has already supplied the custom message, and NULL is
3426 passed to this function.
3427
3428 In case things go wrong while processing this function, causing an error that
3429 may re-enter this function, there is a recursion check.
3430
3431 Arguments:
3432 reason What $smtp_notquit_reason will be set to in the ACL;
3433 if NULL, the ACL is not run
3434 code The error code to return as part of the response
3435 defaultrespond The default message if there's no user_msg
3436
3437 Returns: Nothing
3438 */
3439
3440 void
3441 smtp_notquit_exit(uschar *reason, uschar *code, uschar *defaultrespond, ...)
3442 {
3443 int rc;
3444 uschar *user_msg = NULL;
3445 uschar *log_msg = NULL;
3446
3447 /* Check for recursive acll */
3448
3449 if (fl.smtp_exit_function_called)
3450 {
3451 log_write(0, LOG_PANIC, "smtp_notquit_exit() called more than once (%s)",
3452 reason);
3453 return;
3454 }
3455 fl.smtp_exit_function_called = TRUE;
3456
3457 /* Call the not-QUIT ACL, if there is one, unless no reason is given. */
3458
3459 if (acl_smtp_notquit && reason)
3460 {
3461 smtp_notquit_reason = reason;
3462 if ((rc = acl_check(ACL_WHERE_NOTQUIT, NULL, acl_smtp_notquit, &user_msg,
3463 &log_msg)) == ERROR)
3464 log_write(0, LOG_MAIN|LOG_PANIC, "ACL for not-QUIT returned ERROR: %s",
3465 log_msg);
3466 }
3467
3468 /* Write an SMTP response if we are expected to give one. As the default
3469 responses are all internal, they should always fit in the buffer, but code a
3470 warning, just in case. Note that string_vformat() still leaves a complete
3471 string, even if it is incomplete. */
3472
3473 if (code && defaultrespond)
3474 {
3475 if (user_msg)
3476 smtp_respond(code, 3, TRUE, user_msg);
3477 else
3478 {
3479 uschar buffer[128];
3480 va_list ap;
3481 va_start(ap, defaultrespond);
3482 if (!string_vformat(buffer, sizeof(buffer), CS defaultrespond, ap))
3483 log_write(0, LOG_MAIN|LOG_PANIC, "string too large in smtp_notquit_exit()");
3484 smtp_printf("%s %s\r\n", FALSE, code, buffer);
3485 va_end(ap);
3486 }
3487 mac_smtp_fflush();
3488 }
3489 }
3490
3491
3492
3493
3494 /*************************************************
3495 * Verify HELO argument *
3496 *************************************************/
3497
3498 /* This function is called if helo_verify_hosts or helo_try_verify_hosts is
3499 matched. It is also called from ACL processing if verify = helo is used and
3500 verification was not previously tried (i.e. helo_try_verify_hosts was not
3501 matched). The result of its processing is to set helo_verified and
3502 helo_verify_failed. These variables should both be FALSE for this function to
3503 be called.
3504
3505 Note that EHLO/HELO is legitimately allowed to quote an address literal. Allow
3506 for IPv6 ::ffff: literals.
3507
3508 Argument: none
3509 Returns: TRUE if testing was completed;
3510 FALSE on a temporary failure
3511 */
3512
3513 BOOL
3514 smtp_verify_helo(void)
3515 {
3516 BOOL yield = TRUE;
3517
3518 HDEBUG(D_receive) debug_printf("verifying EHLO/HELO argument \"%s\"\n",
3519 sender_helo_name);
3520
3521 if (sender_helo_name == NULL)
3522 {
3523 HDEBUG(D_receive) debug_printf("no EHLO/HELO command was issued\n");
3524 }
3525
3526 /* Deal with the case of -bs without an IP address */
3527
3528 else if (sender_host_address == NULL)
3529 {
3530 HDEBUG(D_receive) debug_printf("no client IP address: assume success\n");
3531 f.helo_verified = TRUE;
3532 }
3533
3534 /* Deal with the more common case when there is a sending IP address */
3535
3536 else if (sender_helo_name[0] == '[')
3537 {
3538 f.helo_verified = Ustrncmp(sender_helo_name+1, sender_host_address,
3539 Ustrlen(sender_host_address)) == 0;
3540
3541 #if HAVE_IPV6
3542 if (!f.helo_verified)
3543 {
3544 if (strncmpic(sender_host_address, US"::ffff:", 7) == 0)
3545 f.helo_verified = Ustrncmp(sender_helo_name + 1,
3546 sender_host_address + 7, Ustrlen(sender_host_address) - 7) == 0;
3547 }
3548 #endif
3549
3550 HDEBUG(D_receive)
3551 { if (f.helo_verified) debug_printf("matched host address\n"); }
3552 }
3553
3554 /* Do a reverse lookup if one hasn't already given a positive or negative
3555 response. If that fails, or the name doesn't match, try checking with a forward
3556 lookup. */
3557
3558 else
3559 {
3560 if (sender_host_name == NULL && !host_lookup_failed)
3561 yield = host_name_lookup() != DEFER;
3562
3563 /* If a host name is known, check it and all its aliases. */
3564
3565 if (sender_host_name)
3566 if ((f.helo_verified = strcmpic(sender_host_name, sender_helo_name) == 0))
3567 {
3568 sender_helo_dnssec = sender_host_dnssec;
3569 HDEBUG(D_receive) debug_printf("matched host name\n");
3570 }
3571 else
3572 {
3573 uschar **aliases = sender_host_aliases;
3574 while (*aliases)
3575 if ((f.helo_verified = strcmpic(*aliases++, sender_helo_name) == 0))
3576 {
3577 sender_helo_dnssec = sender_host_dnssec;
3578 break;
3579 }
3580
3581 HDEBUG(D_receive) if (f.helo_verified)
3582 debug_printf("matched alias %s\n", *(--aliases));
3583 }
3584
3585 /* Final attempt: try a forward lookup of the helo name */
3586
3587 if (!f.helo_verified)
3588 {
3589 int rc;
3590 host_item h;
3591 dnssec_domains d;
3592 host_item *hh;
3593
3594 h.name = sender_helo_name;
3595 h.address = NULL;
3596 h.mx = MX_NONE;
3597 h.next = NULL;
3598 d.request = US"*";
3599 d.require = US"";
3600
3601 HDEBUG(D_receive) debug_printf("getting IP address for %s\n",
3602 sender_helo_name);
3603 rc = host_find_bydns(&h, NULL, HOST_FIND_BY_A | HOST_FIND_BY_AAAA,
3604 NULL, NULL, NULL, &d, NULL, NULL);
3605 if (rc == HOST_FOUND || rc == HOST_FOUND_LOCAL)
3606 for (hh = &h; hh; hh = hh->next)
3607 if (Ustrcmp(hh->address, sender_host_address) == 0)
3608 {
3609 f.helo_verified = TRUE;
3610 if (h.dnssec == DS_YES) sender_helo_dnssec = TRUE;
3611 HDEBUG(D_receive)
3612 {
3613 debug_printf("IP address for %s matches calling address\n"
3614 "Forward DNS security status: %sverified\n",
3615 sender_helo_name, sender_helo_dnssec ? "" : "un");
3616 }
3617 break;
3618 }
3619 }
3620 }
3621
3622 if (!f.helo_verified) f.helo_verify_failed = TRUE; /* We've tried ... */
3623 return yield;
3624 }
3625
3626
3627
3628
3629 /*************************************************
3630 * Send user response message *
3631 *************************************************/
3632
3633 /* This function is passed a default response code and a user message. It calls
3634 smtp_message_code() to check and possibly modify the response code, and then
3635 calls smtp_respond() to transmit the response. I put this into a function
3636 just to avoid a lot of repetition.
3637
3638 Arguments:
3639 code the response code
3640 user_msg the user message
3641
3642 Returns: nothing
3643 */
3644
3645 static void
3646 smtp_user_msg(uschar *code, uschar *user_msg)
3647 {
3648 int len = 3;
3649 smtp_message_code(&code, &len, &user_msg, NULL, TRUE);
3650 smtp_respond(code, len, TRUE, user_msg);
3651 }
3652
3653
3654
3655 static int
3656 smtp_in_auth(auth_instance *au, uschar ** s, uschar ** ss)
3657 {
3658 const uschar *set_id = NULL;
3659 int rc, i;
3660
3661 /* Run the checking code, passing the remainder of the command line as
3662 data. Initials the $auth<n> variables as empty. Initialize $0 empty and set
3663 it as the only set numerical variable. The authenticator may set $auth<n>
3664 and also set other numeric variables. The $auth<n> variables are preferred
3665 nowadays; the numerical variables remain for backwards compatibility.
3666
3667 Afterwards, have a go at expanding the set_id string, even if
3668 authentication failed - for bad passwords it can be useful to log the
3669 userid. On success, require set_id to expand and exist, and put it in
3670 authenticated_id. Save this in permanent store, as the working store gets
3671 reset at HELO, RSET, etc. */
3672
3673 for (i = 0; i < AUTH_VARS; i++) auth_vars[i] = NULL;
3674 expand_nmax = 0;
3675 expand_nlength[0] = 0; /* $0 contains nothing */
3676
3677 rc = (au->info->servercode)(au, smtp_cmd_data);
3678 if (au->set_id) set_id = expand_string(au->set_id);
3679 expand_nmax = -1; /* Reset numeric variables */
3680 for (i = 0; i < AUTH_VARS; i++) auth_vars[i] = NULL; /* Reset $auth<n> */
3681
3682 /* The value of authenticated_id is stored in the spool file and printed in
3683 log lines. It must not contain binary zeros or newline characters. In
3684 normal use, it never will, but when playing around or testing, this error
3685 can (did) happen. To guard against this, ensure that the id contains only
3686 printing characters. */
3687
3688 if (set_id) set_id = string_printing(set_id);
3689
3690 /* For the non-OK cases, set up additional logging data if set_id
3691 is not empty. */
3692
3693 if (rc != OK)
3694 set_id = set_id && *set_id
3695 ? string_sprintf(" (set_id=%s)", set_id) : US"";
3696
3697 /* Switch on the result */
3698
3699 switch(rc)
3700 {
3701 case OK:
3702 if (!au->set_id || set_id) /* Complete success */
3703 {
3704 if (set_id) authenticated_id = string_copy_malloc(set_id);
3705 sender_host_authenticated = au->name;
3706 sender_host_auth_pubname = au->public_name;
3707 authentication_failed = FALSE;
3708 authenticated_fail_id = NULL; /* Impossible to already be set? */
3709
3710 received_protocol =
3711 (sender_host_address ? protocols : protocols_local)
3712 [pextend + pauthed + (tls_in.active.sock >= 0 ? pcrpted:0)];
3713 *s = *ss = US"235 Authentication succeeded";
3714 authenticated_by = au;
3715 break;
3716 }
3717
3718 /* Authentication succeeded, but we failed to expand the set_id string.
3719 Treat this as a temporary error. */
3720
3721 auth_defer_msg = expand_string_message;
3722 /* Fall through */
3723
3724 case DEFER:
3725 if (set_id) authenticated_fail_id = string_copy_malloc(set_id);
3726 *s = string_sprintf("435 Unable to authenticate at present%s",
3727 auth_defer_user_msg);
3728 *ss = string_sprintf("435 Unable to authenticate at present%s: %s",
3729 set_id, auth_defer_msg);
3730 break;
3731
3732 case BAD64:
3733 *s = *ss = US"501 Invalid base64 data";
3734 break;
3735
3736 case CANCELLED:
3737 *s = *ss = US"501 Authentication cancelled";
3738 break;
3739
3740 case UNEXPECTED:
3741 *s = *ss = US"553 Initial data not expected";
3742 break;
3743
3744 case FAIL:
3745 if (set_id) authenticated_fail_id = string_copy_malloc(set_id);
3746 *s = US"535 Incorrect authentication data";
3747 *ss = string_sprintf("535 Incorrect authentication data%s", set_id);
3748 break;
3749
3750 default:
3751 if (set_id) authenticated_fail_id = string_copy_malloc(set_id);
3752 *s = US"435 Internal error";
3753 *ss = string_sprintf("435 Internal error%s: return %d from authentication "
3754 "check", set_id, rc);
3755 break;
3756 }
3757
3758 return rc;
3759 }
3760
3761
3762
3763
3764
3765 static int
3766 qualify_recipient(uschar ** recipient, uschar * smtp_cmd_data, uschar * tag)
3767 {
3768 int rd;
3769 if (f.allow_unqualified_recipient || strcmpic(*recipient, US"postmaster") == 0)
3770 {
3771 DEBUG(D_receive) debug_printf("unqualified address %s accepted\n",
3772 *recipient);
3773 rd = Ustrlen(recipient) + 1;
3774 *recipient = rewrite_address_qualify(*recipient, TRUE);
3775 return rd;
3776 }
3777 smtp_printf("501 %s: recipient address must contain a domain\r\n", FALSE,
3778 smtp_cmd_data);
3779 log_write(L_smtp_syntax_error,
3780 LOG_MAIN|LOG_REJECT, "unqualified %s rejected: <%s> %s%s",
3781 tag, *recipient, host_and_ident(TRUE), host_lookup_msg);
3782 return 0;
3783 }
3784
3785
3786
3787
3788 static void
3789 smtp_quit_handler(uschar ** user_msgp, uschar ** log_msgp)
3790 {
3791 HAD(SCH_QUIT);
3792 incomplete_transaction_log(US"QUIT");
3793 if (acl_smtp_quit)
3794 {
3795 int rc = acl_check(ACL_WHERE_QUIT, NULL, acl_smtp_quit, user_msgp, log_msgp);
3796 if (rc == ERROR)
3797 log_write(0, LOG_MAIN|LOG_PANIC, "ACL for QUIT returned ERROR: %s",
3798 *log_msgp);
3799 }
3800 if (*user_msgp)
3801 smtp_respond(US"221", 3, TRUE, *user_msgp);
3802 else
3803 smtp_printf("221 %s closing connection\r\n", FALSE, smtp_active_hostname);
3804
3805 #ifdef SUPPORT_TLS
3806 tls_close(NULL, TLS_SHUTDOWN_NOWAIT);
3807 #endif
3808
3809 log_write(L_smtp_connection, LOG_MAIN, "%s closed by QUIT",
3810 smtp_get_connection_info());
3811 }
3812
3813
3814 static void
3815 smtp_rset_handler(void)
3816 {
3817 HAD(SCH_RSET);
3818 incomplete_transaction_log(US"RSET");
3819 smtp_printf("250 Reset OK\r\n", FALSE);
3820 cmd_list[CMD_LIST_RSET].is_mail_cmd = FALSE;
3821 }
3822
3823
3824
3825 /*************************************************
3826 * Initialize for SMTP incoming message *
3827 *************************************************/
3828
3829 /* This function conducts the initial dialogue at the start of an incoming SMTP
3830 message, and builds a list of recipients. However, if the incoming message
3831 is part of a batch (-bS option) a separate function is called since it would
3832 be messy having tests splattered about all over this function. This function
3833 therefore handles the case where interaction is occurring. The input and output
3834 files are set up in smtp_in and smtp_out.
3835
3836 The global recipients_list is set to point to a vector of recipient_item
3837 blocks, whose number is given by recipients_count. This is extended by the
3838 receive_add_recipient() function. The global variable sender_address is set to
3839 the sender's address. The yield is +1 if a message has been successfully
3840 started, 0 if a QUIT command was encountered or the connection was refused from
3841 the particular host, or -1 if the connection was lost.
3842
3843 Argument: none
3844
3845 Returns: > 0 message successfully started (reached DATA)
3846 = 0 QUIT read or end of file reached or call refused
3847 < 0 lost connection
3848 */
3849
3850 int
3851 smtp_setup_msg(void)
3852 {
3853 int done = 0;
3854 BOOL toomany = FALSE;
3855 BOOL discarded = FALSE;
3856 BOOL last_was_rej_mail = FALSE;
3857 BOOL last_was_rcpt = FALSE;
3858 void *reset_point = store_get(0);
3859
3860 DEBUG(D_receive) debug_printf("smtp_setup_msg entered\n");
3861
3862 /* Reset for start of new message. We allow one RSET not to be counted as a
3863 nonmail command, for those MTAs that insist on sending it between every
3864 message. Ditto for EHLO/HELO and for STARTTLS, to allow for going in and out of
3865 TLS between messages (an Exim client may do this if it has messages queued up
3866 for the host). Note: we do NOT reset AUTH at this point. */
3867
3868 smtp_reset(reset_point);
3869 message_ended = END_NOTSTARTED;
3870
3871 chunking_state = f.chunking_offered ? CHUNKING_OFFERED : CHUNKING_NOT_OFFERED;
3872
3873 cmd_list[CMD_LIST_RSET].is_mail_cmd = TRUE;
3874 cmd_list[CMD_LIST_HELO].is_mail_cmd = TRUE;
3875 cmd_list[CMD_LIST_EHLO].is_mail_cmd = TRUE;
3876 #ifdef SUPPORT_TLS
3877 cmd_list[CMD_LIST_STARTTLS].is_mail_cmd = TRUE;
3878 #endif
3879
3880 /* Set the local signal handler for SIGTERM - it tries to end off tidily */
3881
3882 had_command_sigterm = 0;
3883 os_non_restarting_signal(SIGTERM, command_sigterm_handler);
3884
3885 /* Batched SMTP is handled in a different function. */
3886
3887 if (smtp_batched_input) return smtp_setup_batch_msg();
3888
3889 /* Deal with SMTP commands. This loop is exited by setting done to a POSITIVE
3890 value. The values are 2 larger than the required yield of the function. */
3891
3892 while (done <= 0)
3893 {
3894 const uschar **argv;
3895 uschar *etrn_command;
3896 uschar *etrn_serialize_key;
3897 uschar *errmess;
3898 uschar *log_msg, *smtp_code;
3899 uschar *user_msg = NULL;
3900 uschar *recipient = NULL;
3901 uschar *hello = NULL;
3902 uschar *s, *ss;
3903 BOOL was_rej_mail = FALSE;
3904 BOOL was_rcpt = FALSE;
3905 void (*oldsignal)(int);
3906 pid_t pid;
3907 int start, end, sender_domain, recipient_domain;
3908 int rc;
3909 int c;
3910 auth_instance *au;
3911 uschar *orcpt = NULL;
3912 int dsn_flags;
3913 gstring * g;
3914
3915 #ifdef AUTH_TLS
3916 /* Check once per STARTTLS or SSL-on-connect for a TLS AUTH */
3917 if ( tls_in.active.sock >= 0
3918 && tls_in.peercert
3919 && tls_in.certificate_verified
3920 && cmd_list[CMD_LIST_TLS_AUTH].is_mail_cmd
3921 )
3922 {
3923 cmd_list[CMD_LIST_TLS_AUTH].is_mail_cmd = FALSE;
3924
3925 for (au = auths; au; au = au->next)
3926 if (strcmpic(US"tls", au->driver_name) == 0)
3927 {
3928 if ( acl_smtp_auth
3929 && (rc = acl_check(ACL_WHERE_AUTH, NULL, acl_smtp_auth,
3930 &user_msg, &log_msg)) != OK
3931 )
3932 done = smtp_handle_acl_fail(ACL_WHERE_AUTH, rc, user_msg, log_msg);
3933 else
3934 {
3935 smtp_cmd_data = NULL;
3936
3937 if (smtp_in_auth(au, &s, &ss) == OK)
3938 { DEBUG(D_auth) debug_printf("tls auth succeeded\n"); }
3939 else
3940 { DEBUG(D_auth) debug_printf("tls auth not succeeded\n"); }
3941 }
3942 break;
3943 }
3944 }
3945 #endif
3946
3947 #ifdef TCP_QUICKACK
3948 if (smtp_in) /* Avoid pure-ACKs while in cmd pingpong phase */
3949 (void) setsockopt(fileno(smtp_in), IPPROTO_TCP, TCP_QUICKACK,
3950 US &off, sizeof(off));
3951 #endif
3952
3953 switch(smtp_read_command(TRUE, GETC_BUFFER_UNLIMITED))
3954 {
3955 /* The AUTH command is not permitted to occur inside a transaction, and may
3956 occur successfully only once per connection. Actually, that isn't quite
3957 true. When TLS is started, all previous information about a connection must
3958 be discarded, so a new AUTH is permitted at that time.
3959
3960 AUTH may only be used when it has been advertised. However, it seems that
3961 there are clients that send AUTH when it hasn't been advertised, some of
3962 them even doing this after HELO. And there are MTAs that accept this. Sigh.
3963 So there's a get-out that allows this to happen.
3964
3965 AUTH is initially labelled as a "nonmail command" so that one occurrence
3966 doesn't get counted. We change the label here so that multiple failing
3967 AUTHS will eventually hit the nonmail threshold. */
3968
3969 case AUTH_CMD:
3970 HAD(SCH_AUTH);
3971 authentication_failed = TRUE;
3972 cmd_list[CMD_LIST_AUTH].is_mail_cmd = FALSE;
3973
3974 if (!fl.auth_advertised && !f.allow_auth_unadvertised)
3975 {
3976 done = synprot_error(L_smtp_protocol_error, 503, NULL,
3977 US"AUTH command used when not advertised");
3978 break;
3979 }
3980 if (sender_host_authenticated)
3981 {
3982 done = synprot_error(L_smtp_protocol_error, 503, NULL,
3983 US"already authenticated");
3984 break;
3985 }
3986 if (sender_address)
3987 {
3988 done = synprot_error(L_smtp_protocol_error, 503, NULL,
3989 US"not permitted in mail transaction");
3990 break;
3991 }
3992
3993 /* Check the ACL */
3994
3995 if ( acl_smtp_auth
3996 && (rc = acl_check(ACL_WHERE_AUTH, NULL, acl_smtp_auth,
3997 &user_msg, &log_msg)) != OK
3998 )
3999 {
4000 done = smtp_handle_acl_fail(ACL_WHERE_AUTH, rc, user_msg, log_msg);
4001 break;
4002 }
4003
4004 /* Find the name of the requested authentication mechanism. */
4005
4006 s = smtp_cmd_data;
4007 while ((c = *smtp_cmd_data) != 0 && !isspace(c))
4008 {
4009 if (!isalnum(c) && c != '-' && c != '_')
4010 {
4011 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4012 US"invalid character in authentication mechanism name");
4013 goto COMMAND_LOOP;
4014 }
4015 smtp_cmd_data++;
4016 }
4017
4018 /* If not at the end of the line, we must be at white space. Terminate the
4019 name and move the pointer on to any data that may be present. */
4020
4021 if (*smtp_cmd_data != 0)
4022 {
4023 *smtp_cmd_data++ = 0;
4024 while (isspace(*smtp_cmd_data)) smtp_cmd_data++;
4025 }
4026
4027 /* Search for an authentication mechanism which is configured for use
4028 as a server and which has been advertised (unless, sigh, allow_auth_
4029 unadvertised is set). */
4030
4031 for (au = auths; au; au = au->next)
4032 if (strcmpic(s, au->public_name) == 0 && au->server &&
4033 (au->advertised || f.allow_auth_unadvertised))
4034 break;
4035
4036 if (au)
4037 {
4038 c = smtp_in_auth(au, &s, &ss);
4039
4040 smtp_printf("%s\r\n", FALSE, s);
4041 if (c != OK)
4042 log_write(0, LOG_MAIN|LOG_REJECT, "%s authenticator failed for %s: %s",
4043 au->name, host_and_ident(FALSE), ss);
4044 }
4045 else
4046 done = synprot_error(L_smtp_protocol_error, 504, NULL,
4047 string_sprintf("%s authentication mechanism not supported", s));
4048
4049 break; /* AUTH_CMD */
4050
4051 /* The HELO/EHLO commands are permitted to appear in the middle of a
4052 session as well as at the beginning. They have the effect of a reset in
4053 addition to their other functions. Their absence at the start cannot be
4054 taken to be an error.
4055
4056 RFC 2821 says:
4057
4058 If the EHLO command is not acceptable to the SMTP server, 501, 500,
4059 or 502 failure replies MUST be returned as appropriate. The SMTP
4060 server MUST stay in the same state after transmitting these replies
4061 that it was in before the EHLO was received.
4062
4063 Therefore, we do not do the reset until after checking the command for
4064 acceptability. This change was made for Exim release 4.11. Previously
4065 it did the reset first. */
4066
4067 case HELO_CMD:
4068 HAD(SCH_HELO);
4069 hello = US"HELO";
4070 fl.esmtp = FALSE;
4071 goto HELO_EHLO;
4072
4073 case EHLO_CMD:
4074 HAD(SCH_EHLO);
4075 hello = US"EHLO";
4076 fl.esmtp = TRUE;
4077
4078 HELO_EHLO: /* Common code for HELO and EHLO */
4079 cmd_list[CMD_LIST_HELO].is_mail_cmd = FALSE;
4080 cmd_list[CMD_LIST_EHLO].is_mail_cmd = FALSE;
4081
4082 /* Reject the HELO if its argument was invalid or non-existent. A
4083 successful check causes the argument to be saved in malloc store. */
4084
4085 if (!check_helo(smtp_cmd_data))
4086 {
4087 smtp_printf("501 Syntactically invalid %s argument(s)\r\n", FALSE, hello);
4088
4089 log_write(0, LOG_MAIN|LOG_REJECT, "rejected %s from %s: syntactically "
4090 "invalid argument(s): %s", hello, host_and_ident(FALSE),
4091 *smtp_cmd_argument == 0 ? US"(no argument given)" :
4092 string_printing(smtp_cmd_argument));
4093
4094 if (++synprot_error_count > smtp_max_synprot_errors)
4095 {
4096 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
4097 "syntax or protocol errors (last command was \"%s\")",
4098 host_and_ident(FALSE), string_printing(smtp_cmd_buffer));
4099 done = 1;
4100 }
4101
4102 break;
4103 }
4104
4105 /* If sender_host_unknown is true, we have got here via the -bs interface,
4106 not called from inetd. Otherwise, we are running an IP connection and the
4107 host address will be set. If the helo name is the primary name of this
4108 host and we haven't done a reverse lookup, force one now. If helo_required
4109 is set, ensure that the HELO name matches the actual host. If helo_verify
4110 is set, do the same check, but softly. */
4111
4112 if (!f.sender_host_unknown)
4113 {
4114 BOOL old_h