2d213305ece036b724da3c186a00327e6ce7c961
[exim.git] / src / src / smtp_in.c
1 /*************************************************
2 * Exim - an Internet mail transport agent *
3 *************************************************/
4
5 /* Copyright (c) University of Cambridge 1995 - 2018 */
6 /* See the file NOTICE for conditions of use and distribution. */
7
8 /* Functions for handling an incoming SMTP call. */
9
10
11 #include "exim.h"
12 #include <assert.h>
13
14
15 /* Initialize for TCP wrappers if so configured. It appears that the macro
16 HAVE_IPV6 is used in some versions of the tcpd.h header, so we unset it before
17 including that header, and restore its value afterwards. */
18
19 #ifdef USE_TCP_WRAPPERS
20
21 #if HAVE_IPV6
22 #define EXIM_HAVE_IPV6
23 #endif
24 #undef HAVE_IPV6
25 #include <tcpd.h>
26 #undef HAVE_IPV6
27 #ifdef EXIM_HAVE_IPV6
28 #define HAVE_IPV6 TRUE
29 #endif
30
31 int allow_severity = LOG_INFO;
32 int deny_severity = LOG_NOTICE;
33 uschar *tcp_wrappers_name;
34 #endif
35
36
37 /* Size of buffer for reading SMTP commands. We used to use 512, as defined
38 by RFC 821. However, RFC 1869 specifies that this must be increased for SMTP
39 commands that accept arguments, and this in particular applies to AUTH, where
40 the data can be quite long. More recently this value was 2048 in Exim;
41 however, RFC 4954 (circa 2007) recommends 12288 bytes to handle AUTH. Clients
42 such as Thunderbird will send an AUTH with an initial-response for GSSAPI.
43 The maximum size of a Kerberos ticket under Windows 2003 is 12000 bytes, and
44 we need room to handle large base64-encoded AUTHs for GSSAPI.
45 */
46
47 #define SMTP_CMD_BUFFER_SIZE 16384
48
49 /* Size of buffer for reading SMTP incoming packets */
50
51 #define IN_BUFFER_SIZE 8192
52
53 /* Structure for SMTP command list */
54
55 typedef struct {
56 const char *name;
57 int len;
58 short int cmd;
59 short int has_arg;
60 short int is_mail_cmd;
61 } smtp_cmd_list;
62
63 /* Codes for identifying commands. We order them so that those that come first
64 are those for which synchronization is always required. Checking this can help
65 block some spam. */
66
67 enum {
68 /* These commands are required to be synchronized, i.e. to be the last in a
69 block of commands when pipelining. */
70
71 HELO_CMD, EHLO_CMD, DATA_CMD, /* These are listed in the pipelining */
72 VRFY_CMD, EXPN_CMD, NOOP_CMD, /* RFC as requiring synchronization */
73 ETRN_CMD, /* This by analogy with TURN from the RFC */
74 STARTTLS_CMD, /* Required by the STARTTLS RFC */
75 TLS_AUTH_CMD, /* auto-command at start of SSL */
76
77 /* This is a dummy to identify the non-sync commands when pipelining */
78
79 NON_SYNC_CMD_PIPELINING,
80
81 /* These commands need not be synchronized when pipelining */
82
83 MAIL_CMD, RCPT_CMD, RSET_CMD,
84
85 /* This is a dummy to identify the non-sync commands when not pipelining */
86
87 NON_SYNC_CMD_NON_PIPELINING,
88
89 /* RFC3030 section 2: "After all MAIL and RCPT responses are collected and
90 processed the message is sent using a series of BDAT commands"
91 implies that BDAT should be synchronized. However, we see Google, at least,
92 sending MAIL,RCPT,BDAT-LAST in a single packet, clearly not waiting for
93 processing of the RCPT response(s). We shall do the same, and not require
94 synch for BDAT. Worse, as the chunk may (very likely will) follow the
95 command-header in the same packet we cannot do the usual "is there any
96 follow-on data after the command line" even for non-pipeline mode.
97 So we'll need an explicit check after reading the expected chunk amount
98 when non-pipe, before sending the ACK. */
99
100 BDAT_CMD,
101
102 /* I have been unable to find a statement about the use of pipelining
103 with AUTH, so to be on the safe side it is here, though I kind of feel
104 it should be up there with the synchronized commands. */
105
106 AUTH_CMD,
107
108 /* I'm not sure about these, but I don't think they matter. */
109
110 QUIT_CMD, HELP_CMD,
111
112 #ifdef SUPPORT_PROXY
113 PROXY_FAIL_IGNORE_CMD,
114 #endif
115
116 /* These are specials that don't correspond to actual commands */
117
118 EOF_CMD, OTHER_CMD, BADARG_CMD, BADCHAR_CMD, BADSYN_CMD,
119 TOO_MANY_NONMAIL_CMD };
120
121
122 /* This is a convenience macro for adding the identity of an SMTP command
123 to the circular buffer that holds a list of the last n received. */
124
125 #define HAD(n) \
126 smtp_connection_had[smtp_ch_index++] = n; \
127 if (smtp_ch_index >= SMTP_HBUFF_SIZE) smtp_ch_index = 0
128
129
130 /*************************************************
131 * Local static variables *
132 *************************************************/
133
134 static auth_instance *authenticated_by;
135 static BOOL auth_advertised;
136 #ifdef SUPPORT_TLS
137 static BOOL tls_advertised;
138 #endif
139 static BOOL dsn_advertised;
140 static BOOL esmtp;
141 static BOOL helo_required = FALSE;
142 static BOOL helo_verify = FALSE;
143 static BOOL helo_seen;
144 static BOOL helo_accept_junk;
145 static BOOL count_nonmail;
146 static BOOL pipelining_advertised;
147 static BOOL rcpt_smtp_response_same;
148 static BOOL rcpt_in_progress;
149 static int nonmail_command_count;
150 static BOOL smtp_exit_function_called = 0;
151 #ifdef SUPPORT_I18N
152 static BOOL smtputf8_advertised;
153 #endif
154 static int synprot_error_count;
155 static int unknown_command_count;
156 static int sync_cmd_limit;
157 static int smtp_write_error = 0;
158
159 static uschar *rcpt_smtp_response;
160 static uschar *smtp_data_buffer;
161 static uschar *smtp_cmd_data;
162
163 /* We need to know the position of RSET, HELO, EHLO, AUTH, and STARTTLS. Their
164 final fields of all except AUTH are forced TRUE at the start of a new message
165 setup, to allow one of each between messages that is not counted as a nonmail
166 command. (In fact, only one of HELO/EHLO is not counted.) Also, we have to
167 allow a new EHLO after starting up TLS.
168
169 AUTH is "falsely" labelled as a mail command initially, so that it doesn't get
170 counted. However, the flag is changed when AUTH is received, so that multiple
171 failing AUTHs will eventually hit the limit. After a successful AUTH, another
172 AUTH is already forbidden. After a TLS session is started, AUTH's flag is again
173 forced TRUE, to allow for the re-authentication that can happen at that point.
174
175 QUIT is also "falsely" labelled as a mail command so that it doesn't up the
176 count of non-mail commands and possibly provoke an error.
177
178 tls_auth is a pseudo-command, never expected in input. It is activated
179 on TLS startup and looks for a tls authenticator. */
180
181 static smtp_cmd_list cmd_list[] = {
182 /* name len cmd has_arg is_mail_cmd */
183
184 { "rset", sizeof("rset")-1, RSET_CMD, FALSE, FALSE }, /* First */
185 { "helo", sizeof("helo")-1, HELO_CMD, TRUE, FALSE },
186 { "ehlo", sizeof("ehlo")-1, EHLO_CMD, TRUE, FALSE },
187 { "auth", sizeof("auth")-1, AUTH_CMD, TRUE, TRUE },
188 #ifdef SUPPORT_TLS
189 { "starttls", sizeof("starttls")-1, STARTTLS_CMD, FALSE, FALSE },
190 { "tls_auth", 0, TLS_AUTH_CMD, FALSE, FALSE },
191 #endif
192
193 /* If you change anything above here, also fix the definitions below. */
194
195 { "mail from:", sizeof("mail from:")-1, MAIL_CMD, TRUE, TRUE },
196 { "rcpt to:", sizeof("rcpt to:")-1, RCPT_CMD, TRUE, TRUE },
197 { "data", sizeof("data")-1, DATA_CMD, FALSE, TRUE },
198 { "bdat", sizeof("bdat")-1, BDAT_CMD, TRUE, TRUE },
199 { "quit", sizeof("quit")-1, QUIT_CMD, FALSE, TRUE },
200 { "noop", sizeof("noop")-1, NOOP_CMD, TRUE, FALSE },
201 { "etrn", sizeof("etrn")-1, ETRN_CMD, TRUE, FALSE },
202 { "vrfy", sizeof("vrfy")-1, VRFY_CMD, TRUE, FALSE },
203 { "expn", sizeof("expn")-1, EXPN_CMD, TRUE, FALSE },
204 { "help", sizeof("help")-1, HELP_CMD, TRUE, FALSE }
205 };
206
207 static smtp_cmd_list *cmd_list_end =
208 cmd_list + sizeof(cmd_list)/sizeof(smtp_cmd_list);
209
210 #define CMD_LIST_RSET 0
211 #define CMD_LIST_HELO 1
212 #define CMD_LIST_EHLO 2
213 #define CMD_LIST_AUTH 3
214 #define CMD_LIST_STARTTLS 4
215 #define CMD_LIST_TLS_AUTH 5
216
217 /* This list of names is used for performing the smtp_no_mail logging action.
218 It must be kept in step with the SCH_xxx enumerations. */
219
220 static uschar *smtp_names[] =
221 {
222 US"NONE", US"AUTH", US"DATA", US"BDAT", US"EHLO", US"ETRN", US"EXPN",
223 US"HELO", US"HELP", US"MAIL", US"NOOP", US"QUIT", US"RCPT", US"RSET",
224 US"STARTTLS", US"VRFY" };
225
226 static uschar *protocols_local[] = {
227 US"local-smtp", /* HELO */
228 US"local-smtps", /* The rare case EHLO->STARTTLS->HELO */
229 US"local-esmtp", /* EHLO */
230 US"local-esmtps", /* EHLO->STARTTLS->EHLO */
231 US"local-esmtpa", /* EHLO->AUTH */
232 US"local-esmtpsa" /* EHLO->STARTTLS->EHLO->AUTH */
233 };
234 static uschar *protocols[] = {
235 US"smtp", /* HELO */
236 US"smtps", /* The rare case EHLO->STARTTLS->HELO */
237 US"esmtp", /* EHLO */
238 US"esmtps", /* EHLO->STARTTLS->EHLO */
239 US"esmtpa", /* EHLO->AUTH */
240 US"esmtpsa" /* EHLO->STARTTLS->EHLO->AUTH */
241 };
242
243 #define pnormal 0
244 #define pextend 2
245 #define pcrpted 1 /* added to pextend or pnormal */
246 #define pauthed 2 /* added to pextend */
247
248 /* Sanity check and validate optional args to MAIL FROM: envelope */
249 enum {
250 ENV_MAIL_OPT_NULL,
251 ENV_MAIL_OPT_SIZE, ENV_MAIL_OPT_BODY, ENV_MAIL_OPT_AUTH,
252 #ifndef DISABLE_PRDR
253 ENV_MAIL_OPT_PRDR,
254 #endif
255 ENV_MAIL_OPT_RET, ENV_MAIL_OPT_ENVID,
256 #ifdef SUPPORT_I18N
257 ENV_MAIL_OPT_UTF8,
258 #endif
259 };
260 typedef struct {
261 uschar * name; /* option requested during MAIL cmd */
262 int value; /* enum type */
263 BOOL need_value; /* TRUE requires value (name=value pair format)
264 FALSE is a singleton */
265 } env_mail_type_t;
266 static env_mail_type_t env_mail_type_list[] = {
267 { US"SIZE", ENV_MAIL_OPT_SIZE, TRUE },
268 { US"BODY", ENV_MAIL_OPT_BODY, TRUE },
269 { US"AUTH", ENV_MAIL_OPT_AUTH, TRUE },
270 #ifndef DISABLE_PRDR
271 { US"PRDR", ENV_MAIL_OPT_PRDR, FALSE },
272 #endif
273 { US"RET", ENV_MAIL_OPT_RET, TRUE },
274 { US"ENVID", ENV_MAIL_OPT_ENVID, TRUE },
275 #ifdef SUPPORT_I18N
276 { US"SMTPUTF8",ENV_MAIL_OPT_UTF8, FALSE }, /* rfc6531 */
277 #endif
278 /* keep this the last entry */
279 { US"NULL", ENV_MAIL_OPT_NULL, FALSE },
280 };
281
282 /* When reading SMTP from a remote host, we have to use our own versions of the
283 C input-reading functions, in order to be able to flush the SMTP output only
284 when about to read more data from the socket. This is the only way to get
285 optimal performance when the client is using pipelining. Flushing for every
286 command causes a separate packet and reply packet each time; saving all the
287 responses up (when pipelining) combines them into one packet and one response.
288
289 For simplicity, these functions are used for *all* SMTP input, not only when
290 receiving over a socket. However, after setting up a secure socket (SSL), input
291 is read via the OpenSSL library, and another set of functions is used instead
292 (see tls.c).
293
294 These functions are set in the receive_getc etc. variables and called with the
295 same interface as the C functions. However, since there can only ever be
296 one incoming SMTP call, we just use a single buffer and flags. There is no need
297 to implement a complicated private FILE-like structure.*/
298
299 static uschar *smtp_inbuffer;
300 static uschar *smtp_inptr;
301 static uschar *smtp_inend;
302 static int smtp_had_eof;
303 static int smtp_had_error;
304
305
306 /* forward declarations */
307 static int smtp_read_command(BOOL check_sync, unsigned buffer_lim);
308 static int synprot_error(int type, int code, uschar *data, uschar *errmess);
309 static void smtp_quit_handler(uschar **, uschar **);
310 static void smtp_rset_handler(void);
311
312 /*************************************************
313 * Recheck synchronization *
314 *************************************************/
315
316 /* Synchronization checks can never be perfect because a packet may be on its
317 way but not arrived when the check is done. Normally, the checks happen when
318 commands are read: Exim ensures that there is no more input in the input buffer.
319 In normal cases, the response to the command will be fast, and there is no
320 further check.
321
322 However, for some commands an ACL is run, and that can include delays. In those
323 cases, it is useful to do another check on the input just before sending the
324 response. This also applies at the start of a connection. This function does
325 that check by means of the select() function, as long as the facility is not
326 disabled or inappropriate. A failure of select() is ignored.
327
328 When there is unwanted input, we read it so that it appears in the log of the
329 error.
330
331 Arguments: none
332 Returns: TRUE if all is well; FALSE if there is input pending
333 */
334
335 static BOOL
336 wouldblock_reading(void)
337 {
338 int fd, rc;
339 fd_set fds;
340 struct timeval tzero;
341
342 #ifdef SUPPORT_TLS
343 if (tls_in.active >= 0)
344 return !tls_could_read();
345 #endif
346
347 if (smtp_inptr < smtp_inend)
348 return FALSE;
349
350 fd = fileno(smtp_in);
351 FD_ZERO(&fds);
352 FD_SET(fd, &fds);
353 tzero.tv_sec = 0;
354 tzero.tv_usec = 0;
355 rc = select(fd + 1, (SELECT_ARG2_TYPE *)&fds, NULL, NULL, &tzero);
356
357 if (rc <= 0) return TRUE; /* Not ready to read */
358 rc = smtp_getc(GETC_BUFFER_UNLIMITED);
359 if (rc < 0) return TRUE; /* End of file or error */
360
361 smtp_ungetc(rc);
362 return FALSE;
363 }
364
365 static BOOL
366 check_sync(void)
367 {
368 if (!smtp_enforce_sync || !sender_host_address || sender_host_notsocket)
369 return TRUE;
370
371 return wouldblock_reading();
372 }
373
374
375 /* If there's input waiting (and we're doing pipelineing) then we can pipeline
376 a reponse with the one following. */
377
378 static BOOL
379 pipeline_response(void)
380 {
381 if ( !smtp_enforce_sync || !sender_host_address
382 || sender_host_notsocket || !pipelining_advertised)
383 return FALSE;
384
385 return !wouldblock_reading();
386 }
387
388
389
390 /*************************************************
391 * Log incomplete transactions *
392 *************************************************/
393
394 /* This function is called after a transaction has been aborted by RSET, QUIT,
395 connection drops or other errors. It logs the envelope information received
396 so far in order to preserve address verification attempts.
397
398 Argument: string to indicate what aborted the transaction
399 Returns: nothing
400 */
401
402 static void
403 incomplete_transaction_log(uschar *what)
404 {
405 if (sender_address == NULL || /* No transaction in progress */
406 !LOGGING(smtp_incomplete_transaction))
407 return;
408
409 /* Build list of recipients for logging */
410
411 if (recipients_count > 0)
412 {
413 int i;
414 raw_recipients = store_get(recipients_count * sizeof(uschar *));
415 for (i = 0; i < recipients_count; i++)
416 raw_recipients[i] = recipients_list[i].address;
417 raw_recipients_count = recipients_count;
418 }
419
420 log_write(L_smtp_incomplete_transaction, LOG_MAIN|LOG_SENDER|LOG_RECIPIENTS,
421 "%s incomplete transaction (%s)", host_and_ident(TRUE), what);
422 }
423
424
425
426
427 /* Refill the buffer, and notify DKIM verification code.
428 Return false for error or EOF.
429 */
430
431 static BOOL
432 smtp_refill(unsigned lim)
433 {
434 int rc, save_errno;
435 if (!smtp_out) return FALSE;
436 fflush(smtp_out);
437 if (smtp_receive_timeout > 0) alarm(smtp_receive_timeout);
438
439 /* Limit amount read, so non-message data is not fed to DKIM.
440 Take care to not touch the safety NUL at the end of the buffer. */
441
442 rc = read(fileno(smtp_in), smtp_inbuffer, MIN(IN_BUFFER_SIZE-1, lim));
443 save_errno = errno;
444 alarm(0);
445 if (rc <= 0)
446 {
447 /* Must put the error text in fixed store, because this might be during
448 header reading, where it releases unused store above the header. */
449 if (rc < 0)
450 {
451 smtp_had_error = save_errno;
452 smtp_read_error = string_copy_malloc(
453 string_sprintf(" (error: %s)", strerror(save_errno)));
454 }
455 else smtp_had_eof = 1;
456 return FALSE;
457 }
458 #ifndef DISABLE_DKIM
459 dkim_exim_verify_feed(smtp_inbuffer, rc);
460 #endif
461 smtp_inend = smtp_inbuffer + rc;
462 smtp_inptr = smtp_inbuffer;
463 return TRUE;
464 }
465
466 /*************************************************
467 * SMTP version of getc() *
468 *************************************************/
469
470 /* This gets the next byte from the SMTP input buffer. If the buffer is empty,
471 it flushes the output, and refills the buffer, with a timeout. The signal
472 handler is set appropriately by the calling function. This function is not used
473 after a connection has negotiated itself into an TLS/SSL state.
474
475 Arguments: lim Maximum amount to read/buffer
476 Returns: the next character or EOF
477 */
478
479 int
480 smtp_getc(unsigned lim)
481 {
482 if (smtp_inptr >= smtp_inend)
483 if (!smtp_refill(lim))
484 return EOF;
485 return *smtp_inptr++;
486 }
487
488 uschar *
489 smtp_getbuf(unsigned * len)
490 {
491 unsigned size;
492 uschar * buf;
493
494 if (smtp_inptr >= smtp_inend)
495 if (!smtp_refill(*len))
496 { *len = 0; return NULL; }
497
498 if ((size = smtp_inend - smtp_inptr) > *len) size = *len;
499 buf = smtp_inptr;
500 smtp_inptr += size;
501 *len = size;
502 return buf;
503 }
504
505 void
506 smtp_get_cache(void)
507 {
508 #ifndef DISABLE_DKIM
509 int n = smtp_inend - smtp_inptr;
510 if (n > 0)
511 dkim_exim_verify_feed(smtp_inptr, n);
512 #endif
513 }
514
515
516 /* Get a byte from the smtp input, in CHUNKING mode. Handle ack of the
517 previous BDAT chunk and getting new ones when we run out. Uses the
518 underlying smtp_getc or tls_getc both for that and for getting the
519 (buffered) data byte. EOD signals (an expected) no further data.
520 ERR signals a protocol error, and EOF a closed input stream.
521
522 Called from read_bdat_smtp() in receive.c for the message body, but also
523 by the headers read loop in receive_msg(); manipulates chunking_state
524 to handle the BDAT command/response.
525 Placed here due to the correlation with the above smtp_getc(), which it wraps,
526 and also by the need to do smtp command/response handling.
527
528 Arguments: lim (ignored)
529 Returns: the next character or ERR, EOD or EOF
530 */
531
532 int
533 bdat_getc(unsigned lim)
534 {
535 uschar * user_msg = NULL;
536 uschar * log_msg;
537
538 for(;;)
539 {
540 #ifndef DISABLE_DKIM
541 BOOL dkim_save;
542 #endif
543
544 if (chunking_data_left > 0)
545 return lwr_receive_getc(chunking_data_left--);
546
547 receive_getc = lwr_receive_getc;
548 receive_getbuf = lwr_receive_getbuf;
549 receive_ungetc = lwr_receive_ungetc;
550 #ifndef DISABLE_DKIM
551 dkim_save = dkim_collect_input;
552 dkim_collect_input = FALSE;
553 #endif
554
555 /* Unless PIPELINING was offered, there should be no next command
556 until after we ack that chunk */
557
558 if (!pipelining_advertised && !check_sync())
559 {
560 unsigned n = smtp_inend - smtp_inptr;
561 if (n > 32) n = 32;
562
563 incomplete_transaction_log(US"sync failure");
564 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP protocol synchronization error "
565 "(next input sent too soon: pipelining was not advertised): "
566 "rejected \"%s\" %s next input=\"%s\"%s",
567 smtp_cmd_buffer, host_and_ident(TRUE),
568 string_printing(string_copyn(smtp_inptr, n)),
569 smtp_inend - smtp_inptr > n ? "..." : "");
570 (void) synprot_error(L_smtp_protocol_error, 554, NULL,
571 US"SMTP synchronization error");
572 goto repeat_until_rset;
573 }
574
575 /* If not the last, ack the received chunk. The last response is delayed
576 until after the data ACL decides on it */
577
578 if (chunking_state == CHUNKING_LAST)
579 {
580 #ifndef DISABLE_DKIM
581 dkim_exim_verify_feed(NULL, 0); /* notify EOD */
582 #endif
583 return EOD;
584 }
585
586 smtp_printf("250 %u byte chunk received\r\n", FALSE, chunking_datasize);
587 chunking_state = CHUNKING_OFFERED;
588 DEBUG(D_receive) debug_printf("chunking state %d\n", (int)chunking_state);
589
590 /* Expect another BDAT cmd from input. RFC 3030 says nothing about
591 QUIT, RSET or NOOP but handling them seems obvious */
592
593 next_cmd:
594 switch(smtp_read_command(TRUE, 1))
595 {
596 default:
597 (void) synprot_error(L_smtp_protocol_error, 503, NULL,
598 US"only BDAT permissible after non-LAST BDAT");
599
600 repeat_until_rset:
601 switch(smtp_read_command(TRUE, 1))
602 {
603 case QUIT_CMD: smtp_quit_handler(&user_msg, &log_msg); /*FALLTHROUGH */
604 case EOF_CMD: return EOF;
605 case RSET_CMD: smtp_rset_handler(); return ERR;
606 default: if (synprot_error(L_smtp_protocol_error, 503, NULL,
607 US"only RSET accepted now") > 0)
608 return EOF;
609 goto repeat_until_rset;
610 }
611
612 case QUIT_CMD:
613 smtp_quit_handler(&user_msg, &log_msg);
614 /*FALLTHROUGH*/
615 case EOF_CMD:
616 return EOF;
617
618 case RSET_CMD:
619 smtp_rset_handler();
620 return ERR;
621
622 case NOOP_CMD:
623 HAD(SCH_NOOP);
624 smtp_printf("250 OK\r\n", FALSE);
625 goto next_cmd;
626
627 case BDAT_CMD:
628 {
629 int n;
630
631 if (sscanf(CS smtp_cmd_data, "%u %n", &chunking_datasize, &n) < 1)
632 {
633 (void) synprot_error(L_smtp_protocol_error, 501, NULL,
634 US"missing size for BDAT command");
635 return ERR;
636 }
637 chunking_state = strcmpic(smtp_cmd_data+n, US"LAST") == 0
638 ? CHUNKING_LAST : CHUNKING_ACTIVE;
639 chunking_data_left = chunking_datasize;
640 DEBUG(D_receive) debug_printf("chunking state %d, %d bytes\n",
641 (int)chunking_state, chunking_data_left);
642
643 if (chunking_datasize == 0)
644 if (chunking_state == CHUNKING_LAST)
645 return EOD;
646 else
647 {
648 (void) synprot_error(L_smtp_protocol_error, 504, NULL,
649 US"zero size for BDAT command");
650 goto repeat_until_rset;
651 }
652
653 receive_getc = bdat_getc;
654 receive_getbuf = bdat_getbuf; /* r~getbuf is never actually used */
655 receive_ungetc = bdat_ungetc;
656 #ifndef DISABLE_DKIM
657 dkim_collect_input = dkim_save;
658 #endif
659 break; /* to top of main loop */
660 }
661 }
662 }
663 }
664
665 uschar *
666 bdat_getbuf(unsigned * len)
667 {
668 uschar * buf;
669
670 if (chunking_data_left <= 0)
671 { *len = 0; return NULL; }
672
673 if (*len > chunking_data_left) *len = chunking_data_left;
674 buf = lwr_receive_getbuf(len); /* Either smtp_getbuf or tls_getbuf */
675 chunking_data_left -= *len;
676 return buf;
677 }
678
679 void
680 bdat_flush_data(void)
681 {
682 while (chunking_data_left)
683 {
684 unsigned n = chunking_data_left;
685 if (!bdat_getbuf(&n)) break;
686 }
687
688 receive_getc = lwr_receive_getc;
689 receive_getbuf = lwr_receive_getbuf;
690 receive_ungetc = lwr_receive_ungetc;
691
692 if (chunking_state != CHUNKING_LAST)
693 {
694 chunking_state = CHUNKING_OFFERED;
695 DEBUG(D_receive) debug_printf("chunking state %d\n", (int)chunking_state);
696 }
697 }
698
699
700
701
702 /*************************************************
703 * SMTP version of ungetc() *
704 *************************************************/
705
706 /* Puts a character back in the input buffer. Only ever
707 called once.
708
709 Arguments:
710 ch the character
711
712 Returns: the character
713 */
714
715 int
716 smtp_ungetc(int ch)
717 {
718 *--smtp_inptr = ch;
719 return ch;
720 }
721
722
723 int
724 bdat_ungetc(int ch)
725 {
726 chunking_data_left++;
727 return lwr_receive_ungetc(ch);
728 }
729
730
731
732 /*************************************************
733 * SMTP version of feof() *
734 *************************************************/
735
736 /* Tests for a previous EOF
737
738 Arguments: none
739 Returns: non-zero if the eof flag is set
740 */
741
742 int
743 smtp_feof(void)
744 {
745 return smtp_had_eof;
746 }
747
748
749
750
751 /*************************************************
752 * SMTP version of ferror() *
753 *************************************************/
754
755 /* Tests for a previous read error, and returns with errno
756 restored to what it was when the error was detected.
757
758 Arguments: none
759 Returns: non-zero if the error flag is set
760 */
761
762 int
763 smtp_ferror(void)
764 {
765 errno = smtp_had_error;
766 return smtp_had_error;
767 }
768
769
770
771 /*************************************************
772 * Test for characters in the SMTP buffer *
773 *************************************************/
774
775 /* Used at the end of a message
776
777 Arguments: none
778 Returns: TRUE/FALSE
779 */
780
781 BOOL
782 smtp_buffered(void)
783 {
784 return smtp_inptr < smtp_inend;
785 }
786
787
788
789 /*************************************************
790 * Write formatted string to SMTP channel *
791 *************************************************/
792
793 /* This is a separate function so that we don't have to repeat everything for
794 TLS support or debugging. It is global so that the daemon and the
795 authentication functions can use it. It does not return any error indication,
796 because major problems such as dropped connections won't show up till an output
797 flush for non-TLS connections. The smtp_fflush() function is available for
798 checking that: for convenience, TLS output errors are remembered here so that
799 they are also picked up later by smtp_fflush().
800
801 Arguments:
802 format format string
803 more further data expected
804 ... optional arguments
805
806 Returns: nothing
807 */
808
809 void
810 smtp_printf(const char *format, BOOL more, ...)
811 {
812 va_list ap;
813
814 va_start(ap, more);
815 smtp_vprintf(format, more, ap);
816 va_end(ap);
817 }
818
819 /* This is split off so that verify.c:respond_printf() can, in effect, call
820 smtp_printf(), bearing in mind that in C a vararg function can't directly
821 call another vararg function, only a function which accepts a va_list. */
822
823 void
824 smtp_vprintf(const char *format, BOOL more, va_list ap)
825 {
826 BOOL yield;
827
828 yield = string_vformat(big_buffer, big_buffer_size, format, ap);
829
830 DEBUG(D_receive)
831 {
832 void *reset_point = store_get(0);
833 uschar *msg_copy, *cr, *end;
834 msg_copy = string_copy(big_buffer);
835 end = msg_copy + Ustrlen(msg_copy);
836 while ((cr = Ustrchr(msg_copy, '\r')) != NULL) /* lose CRs */
837 memmove(cr, cr + 1, (end--) - cr);
838 debug_printf("SMTP>> %s", msg_copy);
839 store_reset(reset_point);
840 }
841
842 if (!yield)
843 {
844 log_write(0, LOG_MAIN|LOG_PANIC, "string too large in smtp_printf()");
845 smtp_closedown(US"Unexpected error");
846 exim_exit(EXIT_FAILURE, NULL);
847 }
848
849 /* If this is the first output for a (non-batch) RCPT command, see if all RCPTs
850 have had the same. Note: this code is also present in smtp_respond(). It would
851 be tidier to have it only in one place, but when it was added, it was easier to
852 do it that way, so as not to have to mess with the code for the RCPT command,
853 which sometimes uses smtp_printf() and sometimes smtp_respond(). */
854
855 if (rcpt_in_progress)
856 {
857 if (rcpt_smtp_response == NULL)
858 rcpt_smtp_response = string_copy(big_buffer);
859 else if (rcpt_smtp_response_same &&
860 Ustrcmp(rcpt_smtp_response, big_buffer) != 0)
861 rcpt_smtp_response_same = FALSE;
862 rcpt_in_progress = FALSE;
863 }
864
865 /* Now write the string */
866
867 #ifdef SUPPORT_TLS
868 if (tls_in.active >= 0)
869 {
870 if (tls_write(TRUE, big_buffer, Ustrlen(big_buffer), more) < 0)
871 smtp_write_error = -1;
872 }
873 else
874 #endif
875
876 if (fprintf(smtp_out, "%s", big_buffer) < 0) smtp_write_error = -1;
877 }
878
879
880
881 /*************************************************
882 * Flush SMTP out and check for error *
883 *************************************************/
884
885 /* This function isn't currently used within Exim (it detects errors when it
886 tries to read the next SMTP input), but is available for use in local_scan().
887 For non-TLS connections, it flushes the output and checks for errors. For
888 TLS-connections, it checks for a previously-detected TLS write error.
889
890 Arguments: none
891 Returns: 0 for no error; -1 after an error
892 */
893
894 int
895 smtp_fflush(void)
896 {
897 if (tls_in.active < 0 && fflush(smtp_out) != 0) smtp_write_error = -1;
898 return smtp_write_error;
899 }
900
901
902
903 /*************************************************
904 * SMTP command read timeout *
905 *************************************************/
906
907 /* Signal handler for timing out incoming SMTP commands. This attempts to
908 finish off tidily.
909
910 Argument: signal number (SIGALRM)
911 Returns: nothing
912 */
913
914 static void
915 command_timeout_handler(int sig)
916 {
917 sig = sig; /* Keep picky compilers happy */
918 log_write(L_lost_incoming_connection,
919 LOG_MAIN, "SMTP command timeout on%s connection from %s",
920 (tls_in.active >= 0)? " TLS" : "",
921 host_and_ident(FALSE));
922 if (smtp_batched_input)
923 moan_smtp_batch(NULL, "421 SMTP command timeout"); /* Does not return */
924 smtp_notquit_exit(US"command-timeout", US"421",
925 US"%s: SMTP command timeout - closing connection", smtp_active_hostname);
926 exim_exit(EXIT_FAILURE, US"receiving");
927 }
928
929
930
931 /*************************************************
932 * SIGTERM received *
933 *************************************************/
934
935 /* Signal handler for handling SIGTERM. Again, try to finish tidily.
936
937 Argument: signal number (SIGTERM)
938 Returns: nothing
939 */
940
941 static void
942 command_sigterm_handler(int sig)
943 {
944 sig = sig; /* Keep picky compilers happy */
945 log_write(0, LOG_MAIN, "%s closed after SIGTERM", smtp_get_connection_info());
946 if (smtp_batched_input)
947 moan_smtp_batch(NULL, "421 SIGTERM received"); /* Does not return */
948 smtp_notquit_exit(US"signal-exit", US"421",
949 US"%s: Service not available - closing connection", smtp_active_hostname);
950 exim_exit(EXIT_FAILURE, US"receiving");
951 }
952
953
954
955
956 #ifdef SUPPORT_PROXY
957 /*************************************************
958 * Restore socket timeout to previous value *
959 *************************************************/
960 /* If the previous value was successfully retrieved, restore
961 it before returning control to the non-proxy routines
962
963 Arguments: fd - File descriptor for input
964 get_ok - Successfully retrieved previous values
965 tvtmp - Time struct with previous values
966 vslen - Length of time struct
967 Returns: none
968 */
969 static void
970 restore_socket_timeout(int fd, int get_ok, struct timeval * tvtmp, socklen_t vslen)
971 {
972 if (get_ok == 0)
973 (void) setsockopt(fd, SOL_SOCKET, SO_RCVTIMEO, CS tvtmp, vslen);
974 }
975
976 /*************************************************
977 * Check if host is required proxy host *
978 *************************************************/
979 /* The function determines if inbound host will be a regular smtp host
980 or if it is configured that it must use Proxy Protocol. A local
981 connection cannot.
982
983 Arguments: none
984 Returns: bool
985 */
986
987 static BOOL
988 check_proxy_protocol_host()
989 {
990 int rc;
991
992 if ( sender_host_address
993 && (rc = verify_check_this_host(CUSS &hosts_proxy, NULL, NULL,
994 sender_host_address, NULL)) == OK)
995 {
996 DEBUG(D_receive)
997 debug_printf("Detected proxy protocol configured host\n");
998 proxy_session = TRUE;
999 }
1000 return proxy_session;
1001 }
1002
1003
1004 /*************************************************
1005 * Read data until newline or end of buffer *
1006 *************************************************/
1007 /* While SMTP is server-speaks-first, TLS is client-speaks-first, so we can't
1008 read an entire buffer and assume there will be nothing past a proxy protocol
1009 header. Our approach normally is to use stdio, but again that relies upon
1010 "STARTTLS\r\n" and a server response before the client starts TLS handshake, or
1011 reading _nothing_ before client TLS handshake. So we don't want to use the
1012 usual buffering reads which may read enough to block TLS starting.
1013
1014 So unfortunately we're down to "read one byte at a time, with a syscall each,
1015 and expect a little overhead", for all proxy-opened connections which are v1,
1016 just to handle the TLS-on-connect case. Since SSL functions wrap the
1017 underlying fd, we can't assume that we can feed them any already-read content.
1018
1019 We need to know where to read to, the max capacity, and we'll read until we
1020 get a CR and one more character. Let the caller scream if it's CR+!LF.
1021
1022 Return the amount read.
1023 */
1024
1025 static int
1026 swallow_until_crlf(int fd, uschar *base, int already, int capacity)
1027 {
1028 uschar *to = base + already;
1029 uschar *cr;
1030 int have = 0;
1031 int ret;
1032 int last = 0;
1033
1034 /* For "PROXY UNKNOWN\r\n" we, at time of writing, expect to have read
1035 up through the \r; for the _normal_ case, we haven't yet seen the \r. */
1036
1037 cr = memchr(base, '\r', already);
1038 if (cr != NULL)
1039 {
1040 if ((cr - base) < already - 1)
1041 {
1042 /* \r and presumed \n already within what we have; probably not
1043 actually proxy protocol, but abort cleanly. */
1044 return 0;
1045 }
1046 /* \r is last character read, just need one more. */
1047 last = 1;
1048 }
1049
1050 while (capacity > 0)
1051 {
1052 do { ret = recv(fd, to, 1, 0); } while (ret == -1 && errno == EINTR);
1053 if (ret == -1)
1054 return -1;
1055 have++;
1056 if (last)
1057 return have;
1058 if (*to == '\r')
1059 last = 1;
1060 capacity--;
1061 to++;
1062 }
1063
1064 /* reached end without having room for a final newline, abort */
1065 errno = EOVERFLOW;
1066 return -1;
1067 }
1068
1069 /*************************************************
1070 * Setup host for proxy protocol *
1071 *************************************************/
1072 /* The function configures the connection based on a header from the
1073 inbound host to use Proxy Protocol. The specification is very exact
1074 so exit with an error if do not find the exact required pieces. This
1075 includes an incorrect number of spaces separating args.
1076
1077 Arguments: none
1078 Returns: Boolean success
1079 */
1080
1081 static void
1082 setup_proxy_protocol_host()
1083 {
1084 union {
1085 struct {
1086 uschar line[108];
1087 } v1;
1088 struct {
1089 uschar sig[12];
1090 uint8_t ver_cmd;
1091 uint8_t fam;
1092 uint16_t len;
1093 union {
1094 struct { /* TCP/UDP over IPv4, len = 12 */
1095 uint32_t src_addr;
1096 uint32_t dst_addr;
1097 uint16_t src_port;
1098 uint16_t dst_port;
1099 } ip4;
1100 struct { /* TCP/UDP over IPv6, len = 36 */
1101 uint8_t src_addr[16];
1102 uint8_t dst_addr[16];
1103 uint16_t src_port;
1104 uint16_t dst_port;
1105 } ip6;
1106 struct { /* AF_UNIX sockets, len = 216 */
1107 uschar src_addr[108];
1108 uschar dst_addr[108];
1109 } unx;
1110 } addr;
1111 } v2;
1112 } hdr;
1113
1114 /* Temp variables used in PPv2 address:port parsing */
1115 uint16_t tmpport;
1116 char tmpip[INET_ADDRSTRLEN];
1117 struct sockaddr_in tmpaddr;
1118 char tmpip6[INET6_ADDRSTRLEN];
1119 struct sockaddr_in6 tmpaddr6;
1120
1121 /* We can't read "all data until end" because while SMTP is
1122 server-speaks-first, the TLS handshake is client-speaks-first, so for
1123 TLS-on-connect ports the proxy protocol header will usually be immediately
1124 followed by a TLS handshake, and with N TLS libraries, we can't reliably
1125 reinject data for reading by those. So instead we first read "enough to be
1126 safely read within the header, and figure out how much more to read".
1127 For v1 we will later read to the end-of-line, for v2 we will read based upon
1128 the stated length.
1129
1130 The v2 sig is 12 octets, and another 4 gets us the length, so we know how much
1131 data is needed total. For v1, where the line looks like:
1132 PROXY TCPn L3src L3dest SrcPort DestPort \r\n
1133
1134 However, for v1 there's also `PROXY UNKNOWN\r\n` which is only 15 octets.
1135 We seem to support that. So, if we read 14 octets then we can tell if we're
1136 v2 or v1. If we're v1, we can continue reading as normal.
1137
1138 If we're v2, we can't slurp up the entire header. We need the length in the
1139 15th & 16th octets, then to read everything after that.
1140
1141 So to safely handle v1 and v2, with client-sent-first supported correctly,
1142 we have to do a minimum of 3 read calls, not 1. Eww.
1143 */
1144
1145 #define PROXY_INITIAL_READ 14
1146 #define PROXY_V2_HEADER_SIZE 16
1147 #if PROXY_INITIAL_READ > PROXY_V2_HEADER_SIZE
1148 # error Code bug in sizes of data to read for proxy usage
1149 #endif
1150
1151 int get_ok = 0;
1152 int size, ret;
1153 int fd = fileno(smtp_in);
1154 const char v2sig[12] = "\x0D\x0A\x0D\x0A\x00\x0D\x0A\x51\x55\x49\x54\x0A";
1155 uschar * iptype; /* To display debug info */
1156 struct timeval tv;
1157 struct timeval tvtmp;
1158 socklen_t vslen = sizeof(struct timeval);
1159 BOOL yield = FALSE;
1160
1161 /* Save current socket timeout values */
1162 get_ok = getsockopt(fd, SOL_SOCKET, SO_RCVTIMEO, CS &tvtmp, &vslen);
1163
1164 /* Proxy Protocol host must send header within a short time
1165 (default 3 seconds) or it's considered invalid */
1166 tv.tv_sec = PROXY_NEGOTIATION_TIMEOUT_SEC;
1167 tv.tv_usec = PROXY_NEGOTIATION_TIMEOUT_USEC;
1168 if (setsockopt(fd, SOL_SOCKET, SO_RCVTIMEO, CS &tv, sizeof(tv)) < 0)
1169 goto bad;
1170
1171 do
1172 {
1173 /* The inbound host was declared to be a Proxy Protocol host, so
1174 don't do a PEEK into the data, actually slurp up enough to be
1175 "safe". Can't take it all because TLS-on-connect clients follow
1176 immediately with TLS handshake. */
1177 ret = recv(fd, &hdr, PROXY_INITIAL_READ, 0);
1178 }
1179 while (ret == -1 && errno == EINTR);
1180
1181 if (ret == -1)
1182 goto proxyfail;
1183
1184 /* For v2, handle reading the length, and then the rest. */
1185 if ((ret == PROXY_INITIAL_READ) && (memcmp(&hdr.v2, v2sig, sizeof(v2sig)) == 0))
1186 {
1187 int retmore;
1188 uint8_t ver;
1189
1190 /* First get the length fields. */
1191 do
1192 {
1193 retmore = recv(fd, (uschar*)&hdr + ret, PROXY_V2_HEADER_SIZE - PROXY_INITIAL_READ, 0);
1194 } while (retmore == -1 && errno == EINTR);
1195 if (retmore == -1)
1196 goto proxyfail;
1197 ret += retmore;
1198
1199 ver = (hdr.v2.ver_cmd & 0xf0) >> 4;
1200
1201 /* May 2014: haproxy combined the version and command into one byte to
1202 allow two full bytes for the length field in order to proxy SSL
1203 connections. SSL Proxy is not supported in this version of Exim, but
1204 must still separate values here. */
1205
1206 if (ver != 0x02)
1207 {
1208 DEBUG(D_receive) debug_printf("Invalid Proxy Protocol version: %d\n", ver);
1209 goto proxyfail;
1210 }
1211
1212 /* The v2 header will always be 16 bytes per the spec. */
1213 size = 16 + ntohs(hdr.v2.len);
1214 DEBUG(D_receive) debug_printf("Detected PROXYv2 header, size %d (limit %d)\n",
1215 size, (int)sizeof(hdr));
1216
1217 /* We should now have 16 octets (PROXY_V2_HEADER_SIZE), and we know the total
1218 amount that we need. Double-check that the size is not unreasonable, then
1219 get the rest. */
1220 if (size > sizeof(hdr))
1221 {
1222 DEBUG(D_receive) debug_printf("PROXYv2 header size unreasonably large; security attack?\n");
1223 goto proxyfail;
1224 }
1225
1226 do
1227 {
1228 do
1229 {
1230 retmore = recv(fd, (uschar*)&hdr + ret, size-ret, 0);
1231 } while (retmore == -1 && errno == EINTR);
1232 if (retmore == -1)
1233 goto proxyfail;
1234 ret += retmore;
1235 DEBUG(D_receive) debug_printf("PROXYv2: have %d/%d required octets\n", ret, size);
1236 } while (ret < size);
1237
1238 } /* end scope for getting rest of data for v2 */
1239
1240 /* At this point: if PROXYv2, we've read the exact size required for all data;
1241 if PROXYv1 then we've read "less than required for any valid line" and should
1242 read the rest". */
1243
1244 if (ret >= 16 && memcmp(&hdr.v2, v2sig, 12) == 0)
1245 {
1246 uint8_t cmd = (hdr.v2.ver_cmd & 0x0f);
1247
1248 switch (cmd)
1249 {
1250 case 0x01: /* PROXY command */
1251 switch (hdr.v2.fam)
1252 {
1253 case 0x11: /* TCPv4 address type */
1254 iptype = US"IPv4";
1255 tmpaddr.sin_addr.s_addr = hdr.v2.addr.ip4.src_addr;
1256 inet_ntop(AF_INET, &tmpaddr.sin_addr, CS &tmpip, sizeof(tmpip));
1257 if (!string_is_ip_address(US tmpip, NULL))
1258 {
1259 DEBUG(D_receive) debug_printf("Invalid %s source IP\n", iptype);
1260 goto proxyfail;
1261 }
1262 proxy_local_address = sender_host_address;
1263 sender_host_address = string_copy(US tmpip);
1264 tmpport = ntohs(hdr.v2.addr.ip4.src_port);
1265 proxy_local_port = sender_host_port;
1266 sender_host_port = tmpport;
1267 /* Save dest ip/port */
1268 tmpaddr.sin_addr.s_addr = hdr.v2.addr.ip4.dst_addr;
1269 inet_ntop(AF_INET, &tmpaddr.sin_addr, CS &tmpip, sizeof(tmpip));
1270 if (!string_is_ip_address(US tmpip, NULL))
1271 {
1272 DEBUG(D_receive) debug_printf("Invalid %s dest port\n", iptype);
1273 goto proxyfail;
1274 }
1275 proxy_external_address = string_copy(US tmpip);
1276 tmpport = ntohs(hdr.v2.addr.ip4.dst_port);
1277 proxy_external_port = tmpport;
1278 goto done;
1279 case 0x21: /* TCPv6 address type */
1280 iptype = US"IPv6";
1281 memmove(tmpaddr6.sin6_addr.s6_addr, hdr.v2.addr.ip6.src_addr, 16);
1282 inet_ntop(AF_INET6, &tmpaddr6.sin6_addr, CS &tmpip6, sizeof(tmpip6));
1283 if (!string_is_ip_address(US tmpip6, NULL))
1284 {
1285 DEBUG(D_receive) debug_printf("Invalid %s source IP\n", iptype);
1286 goto proxyfail;
1287 }
1288 proxy_local_address = sender_host_address;
1289 sender_host_address = string_copy(US tmpip6);
1290 tmpport = ntohs(hdr.v2.addr.ip6.src_port);
1291 proxy_local_port = sender_host_port;
1292 sender_host_port = tmpport;
1293 /* Save dest ip/port */
1294 memmove(tmpaddr6.sin6_addr.s6_addr, hdr.v2.addr.ip6.dst_addr, 16);
1295 inet_ntop(AF_INET6, &tmpaddr6.sin6_addr, CS &tmpip6, sizeof(tmpip6));
1296 if (!string_is_ip_address(US tmpip6, NULL))
1297 {
1298 DEBUG(D_receive) debug_printf("Invalid %s dest port\n", iptype);
1299 goto proxyfail;
1300 }
1301 proxy_external_address = string_copy(US tmpip6);
1302 tmpport = ntohs(hdr.v2.addr.ip6.dst_port);
1303 proxy_external_port = tmpport;
1304 goto done;
1305 default:
1306 DEBUG(D_receive)
1307 debug_printf("Unsupported PROXYv2 connection type: 0x%02x\n",
1308 hdr.v2.fam);
1309 goto proxyfail;
1310 }
1311 /* Unsupported protocol, keep local connection address */
1312 break;
1313 case 0x00: /* LOCAL command */
1314 /* Keep local connection address for LOCAL */
1315 iptype = US"local";
1316 break;
1317 default:
1318 DEBUG(D_receive)
1319 debug_printf("Unsupported PROXYv2 command: 0x%x\n", cmd);
1320 goto proxyfail;
1321 }
1322 }
1323 else if (ret >= 8 && memcmp(hdr.v1.line, "PROXY", 5) == 0)
1324 {
1325 uschar *p;
1326 uschar *end;
1327 uschar *sp; /* Utility variables follow */
1328 int tmp_port;
1329 int r2;
1330 char *endc;
1331
1332 /* get the rest of the line */
1333 r2 = swallow_until_crlf(fd, (uschar*)&hdr, ret, sizeof(hdr)-ret);
1334 if (r2 == -1)
1335 goto proxyfail;
1336 ret += r2;
1337
1338 p = string_copy(hdr.v1.line);
1339 end = memchr(p, '\r', ret - 1);
1340
1341 if (!end || (end == (uschar*)&hdr + ret) || end[1] != '\n')
1342 {
1343 DEBUG(D_receive) debug_printf("Partial or invalid PROXY header\n");
1344 goto proxyfail;
1345 }
1346 *end = '\0'; /* Terminate the string */
1347 size = end + 2 - p; /* Skip header + CRLF */
1348 DEBUG(D_receive) debug_printf("Detected PROXYv1 header\n");
1349 DEBUG(D_receive) debug_printf("Bytes read not within PROXY header: %d\n", ret - size);
1350 /* Step through the string looking for the required fields. Ensure
1351 strict adherence to required formatting, exit for any error. */
1352 p += 5;
1353 if (!isspace(*(p++)))
1354 {
1355 DEBUG(D_receive) debug_printf("Missing space after PROXY command\n");
1356 goto proxyfail;
1357 }
1358 if (!Ustrncmp(p, CCS"TCP4", 4))
1359 iptype = US"IPv4";
1360 else if (!Ustrncmp(p,CCS"TCP6", 4))
1361 iptype = US"IPv6";
1362 else if (!Ustrncmp(p,CCS"UNKNOWN", 7))
1363 {
1364 iptype = US"Unknown";
1365 goto done;
1366 }
1367 else
1368 {
1369 DEBUG(D_receive) debug_printf("Invalid TCP type\n");
1370 goto proxyfail;
1371 }
1372
1373 p += Ustrlen(iptype);
1374 if (!isspace(*(p++)))
1375 {
1376 DEBUG(D_receive) debug_printf("Missing space after TCP4/6 command\n");
1377 goto proxyfail;
1378 }
1379 /* Find the end of the arg */
1380 if ((sp = Ustrchr(p, ' ')) == NULL)
1381 {
1382 DEBUG(D_receive)
1383 debug_printf("Did not find proxied src %s\n", iptype);
1384 goto proxyfail;
1385 }
1386 *sp = '\0';
1387 if(!string_is_ip_address(p, NULL))
1388 {
1389 DEBUG(D_receive)
1390 debug_printf("Proxied src arg is not an %s address\n", iptype);
1391 goto proxyfail;
1392 }
1393 proxy_local_address = sender_host_address;
1394 sender_host_address = p;
1395 p = sp + 1;
1396 if ((sp = Ustrchr(p, ' ')) == NULL)
1397 {
1398 DEBUG(D_receive)
1399 debug_printf("Did not find proxy dest %s\n", iptype);
1400 goto proxyfail;
1401 }
1402 *sp = '\0';
1403 if(!string_is_ip_address(p, NULL))
1404 {
1405 DEBUG(D_receive)
1406 debug_printf("Proxy dest arg is not an %s address\n", iptype);
1407 goto proxyfail;
1408 }
1409 proxy_external_address = p;
1410 p = sp + 1;
1411 if ((sp = Ustrchr(p, ' ')) == NULL)
1412 {
1413 DEBUG(D_receive) debug_printf("Did not find proxied src port\n");
1414 goto proxyfail;
1415 }
1416 *sp = '\0';
1417 tmp_port = strtol(CCS p, &endc, 10);
1418 if (*endc || tmp_port == 0)
1419 {
1420 DEBUG(D_receive)
1421 debug_printf("Proxied src port '%s' not an integer\n", p);
1422 goto proxyfail;
1423 }
1424 proxy_local_port = sender_host_port;
1425 sender_host_port = tmp_port;
1426 p = sp + 1;
1427 if ((sp = Ustrchr(p, '\0')) == NULL)
1428 {
1429 DEBUG(D_receive) debug_printf("Did not find proxy dest port\n");
1430 goto proxyfail;
1431 }
1432 tmp_port = strtol(CCS p, &endc, 10);
1433 if (*endc || tmp_port == 0)
1434 {
1435 DEBUG(D_receive)
1436 debug_printf("Proxy dest port '%s' not an integer\n", p);
1437 goto proxyfail;
1438 }
1439 proxy_external_port = tmp_port;
1440 /* Already checked for /r /n above. Good V1 header received. */
1441 }
1442 else
1443 {
1444 /* Wrong protocol */
1445 DEBUG(D_receive) debug_printf("Invalid proxy protocol version negotiation\n");
1446 (void) swallow_until_crlf(fd, (uschar*)&hdr, ret, sizeof(hdr)-ret);
1447 goto proxyfail;
1448 }
1449
1450 done:
1451 DEBUG(D_receive)
1452 debug_printf("Valid %s sender from Proxy Protocol header\n", iptype);
1453 yield = proxy_session;
1454
1455 /* Don't flush any potential buffer contents. Any input on proxyfail
1456 should cause a synchronization failure */
1457
1458 proxyfail:
1459 restore_socket_timeout(fd, get_ok, &tvtmp, vslen);
1460
1461 bad:
1462 if (yield)
1463 {
1464 sender_host_name = NULL;
1465 (void) host_name_lookup();
1466 host_build_sender_fullhost();
1467 }
1468 else
1469 {
1470 proxy_session_failed = TRUE;
1471 DEBUG(D_receive)
1472 debug_printf("Failure to extract proxied host, only QUIT allowed\n");
1473 }
1474
1475 return;
1476 }
1477 #endif
1478
1479 /*************************************************
1480 * Read one command line *
1481 *************************************************/
1482
1483 /* Strictly, SMTP commands coming over the net are supposed to end with CRLF.
1484 There are sites that don't do this, and in any case internal SMTP probably
1485 should check only for LF. Consequently, we check here for LF only. The line
1486 ends up with [CR]LF removed from its end. If we get an overlong line, treat as
1487 an unknown command. The command is read into the global smtp_cmd_buffer so that
1488 it is available via $smtp_command.
1489
1490 The character reading routine sets up a timeout for each block actually read
1491 from the input (which may contain more than one command). We set up a special
1492 signal handler that closes down the session on a timeout. Control does not
1493 return when it runs.
1494
1495 Arguments:
1496 check_sync if TRUE, check synchronization rules if global option is TRUE
1497 buffer_lim maximum to buffer in lower layer
1498
1499 Returns: a code identifying the command (enumerated above)
1500 */
1501
1502 static int
1503 smtp_read_command(BOOL check_sync, unsigned buffer_lim)
1504 {
1505 int c;
1506 int ptr = 0;
1507 smtp_cmd_list *p;
1508 BOOL hadnull = FALSE;
1509
1510 os_non_restarting_signal(SIGALRM, command_timeout_handler);
1511
1512 while ((c = (receive_getc)(buffer_lim)) != '\n' && c != EOF)
1513 {
1514 if (ptr >= SMTP_CMD_BUFFER_SIZE)
1515 {
1516 os_non_restarting_signal(SIGALRM, sigalrm_handler);
1517 return OTHER_CMD;
1518 }
1519 if (c == 0)
1520 {
1521 hadnull = TRUE;
1522 c = '?';
1523 }
1524 smtp_cmd_buffer[ptr++] = c;
1525 }
1526
1527 receive_linecount++; /* For BSMTP errors */
1528 os_non_restarting_signal(SIGALRM, sigalrm_handler);
1529
1530 /* If hit end of file, return pseudo EOF command. Whether we have a
1531 part-line already read doesn't matter, since this is an error state. */
1532
1533 if (c == EOF) return EOF_CMD;
1534
1535 /* Remove any CR and white space at the end of the line, and terminate the
1536 string. */
1537
1538 while (ptr > 0 && isspace(smtp_cmd_buffer[ptr-1])) ptr--;
1539 smtp_cmd_buffer[ptr] = 0;
1540
1541 DEBUG(D_receive) debug_printf("SMTP<< %s\n", smtp_cmd_buffer);
1542
1543 /* NULLs are not allowed in SMTP commands */
1544
1545 if (hadnull) return BADCHAR_CMD;
1546
1547 /* Scan command list and return identity, having set the data pointer
1548 to the start of the actual data characters. Check for SMTP synchronization
1549 if required. */
1550
1551 for (p = cmd_list; p < cmd_list_end; p++)
1552 {
1553 #ifdef SUPPORT_PROXY
1554 /* Only allow QUIT command if Proxy Protocol parsing failed */
1555 if (proxy_session && proxy_session_failed && p->cmd != QUIT_CMD)
1556 continue;
1557 #endif
1558 if ( p->len
1559 && strncmpic(smtp_cmd_buffer, US p->name, p->len) == 0
1560 && ( smtp_cmd_buffer[p->len-1] == ':' /* "mail from:" or "rcpt to:" */
1561 || smtp_cmd_buffer[p->len] == 0
1562 || smtp_cmd_buffer[p->len] == ' '
1563 ) )
1564 {
1565 if (smtp_inptr < smtp_inend && /* Outstanding input */
1566 p->cmd < sync_cmd_limit && /* Command should sync */
1567 check_sync && /* Local flag set */
1568 smtp_enforce_sync && /* Global flag set */
1569 sender_host_address != NULL && /* Not local input */
1570 !sender_host_notsocket) /* Really is a socket */
1571 return BADSYN_CMD;
1572
1573 /* The variables $smtp_command and $smtp_command_argument point into the
1574 unmodified input buffer. A copy of the latter is taken for actual
1575 processing, so that it can be chopped up into separate parts if necessary,
1576 for example, when processing a MAIL command options such as SIZE that can
1577 follow the sender address. */
1578
1579 smtp_cmd_argument = smtp_cmd_buffer + p->len;
1580 while (isspace(*smtp_cmd_argument)) smtp_cmd_argument++;
1581 Ustrcpy(smtp_data_buffer, smtp_cmd_argument);
1582 smtp_cmd_data = smtp_data_buffer;
1583
1584 /* Count non-mail commands from those hosts that are controlled in this
1585 way. The default is all hosts. We don't waste effort checking the list
1586 until we get a non-mail command, but then cache the result to save checking
1587 again. If there's a DEFER while checking the host, assume it's in the list.
1588
1589 Note that one instance of RSET, EHLO/HELO, and STARTTLS is allowed at the
1590 start of each incoming message by fiddling with the value in the table. */
1591
1592 if (!p->is_mail_cmd)
1593 {
1594 if (count_nonmail == TRUE_UNSET) count_nonmail =
1595 verify_check_host(&smtp_accept_max_nonmail_hosts) != FAIL;
1596 if (count_nonmail && ++nonmail_command_count > smtp_accept_max_nonmail)
1597 return TOO_MANY_NONMAIL_CMD;
1598 }
1599
1600 /* If there is data for a command that does not expect it, generate the
1601 error here. */
1602
1603 return (p->has_arg || *smtp_cmd_data == 0)? p->cmd : BADARG_CMD;
1604 }
1605 }
1606
1607 #ifdef SUPPORT_PROXY
1608 /* Only allow QUIT command if Proxy Protocol parsing failed */
1609 if (proxy_session && proxy_session_failed)
1610 return PROXY_FAIL_IGNORE_CMD;
1611 #endif
1612
1613 /* Enforce synchronization for unknown commands */
1614
1615 if ( smtp_inptr < smtp_inend /* Outstanding input */
1616 && check_sync /* Local flag set */
1617 && smtp_enforce_sync /* Global flag set */
1618 && sender_host_address /* Not local input */
1619 && !sender_host_notsocket) /* Really is a socket */
1620 return BADSYN_CMD;
1621
1622 return OTHER_CMD;
1623 }
1624
1625
1626
1627 /*************************************************
1628 * Forced closedown of call *
1629 *************************************************/
1630
1631 /* This function is called from log.c when Exim is dying because of a serious
1632 disaster, and also from some other places. If an incoming non-batched SMTP
1633 channel is open, it swallows the rest of the incoming message if in the DATA
1634 phase, sends the reply string, and gives an error to all subsequent commands
1635 except QUIT. The existence of an SMTP call is detected by the non-NULLness of
1636 smtp_in.
1637
1638 Arguments:
1639 message SMTP reply string to send, excluding the code
1640
1641 Returns: nothing
1642 */
1643
1644 void
1645 smtp_closedown(uschar *message)
1646 {
1647 if (!smtp_in || smtp_batched_input) return;
1648 receive_swallow_smtp();
1649 smtp_printf("421 %s\r\n", FALSE, message);
1650
1651 for (;;) switch(smtp_read_command(FALSE, GETC_BUFFER_UNLIMITED))
1652 {
1653 case EOF_CMD:
1654 return;
1655
1656 case QUIT_CMD:
1657 smtp_printf("221 %s closing connection\r\n", FALSE, smtp_active_hostname);
1658 mac_smtp_fflush();
1659 return;
1660
1661 case RSET_CMD:
1662 smtp_printf("250 Reset OK\r\n", FALSE);
1663 break;
1664
1665 default:
1666 smtp_printf("421 %s\r\n", FALSE, message);
1667 break;
1668 }
1669 }
1670
1671
1672
1673
1674 /*************************************************
1675 * Set up connection info for logging *
1676 *************************************************/
1677
1678 /* This function is called when logging information about an SMTP connection.
1679 It sets up appropriate source information, depending on the type of connection.
1680 If sender_fullhost is NULL, we are at a very early stage of the connection;
1681 just use the IP address.
1682
1683 Argument: none
1684 Returns: a string describing the connection
1685 */
1686
1687 uschar *
1688 smtp_get_connection_info(void)
1689 {
1690 const uschar * hostname = sender_fullhost
1691 ? sender_fullhost : sender_host_address;
1692
1693 if (host_checking)
1694 return string_sprintf("SMTP connection from %s", hostname);
1695
1696 if (sender_host_unknown || sender_host_notsocket)
1697 return string_sprintf("SMTP connection from %s", sender_ident);
1698
1699 if (is_inetd)
1700 return string_sprintf("SMTP connection from %s (via inetd)", hostname);
1701
1702 if (LOGGING(incoming_interface) && interface_address != NULL)
1703 return string_sprintf("SMTP connection from %s I=[%s]:%d", hostname,
1704 interface_address, interface_port);
1705
1706 return string_sprintf("SMTP connection from %s", hostname);
1707 }
1708
1709
1710
1711 #ifdef SUPPORT_TLS
1712 /* Append TLS-related information to a log line
1713
1714 Arguments:
1715 g String under construction: allocated string to extend, or NULL
1716
1717 Returns: Allocated string or NULL
1718 */
1719 static gstring *
1720 s_tlslog(gstring * g)
1721 {
1722 if (LOGGING(tls_cipher) && tls_in.cipher)
1723 g = string_append(g, 2, US" X=", tls_in.cipher);
1724 if (LOGGING(tls_certificate_verified) && tls_in.cipher)
1725 g = string_append(g, 2, US" CV=", tls_in.certificate_verified? "yes":"no");
1726 if (LOGGING(tls_peerdn) && tls_in.peerdn)
1727 g = string_append(g, 3, US" DN=\"", string_printing(tls_in.peerdn), US"\"");
1728 if (LOGGING(tls_sni) && tls_in.sni)
1729 g = string_append(g, 3, US" SNI=\"", string_printing(tls_in.sni), US"\"");
1730 return g;
1731 }
1732 #endif
1733
1734 /*************************************************
1735 * Log lack of MAIL if so configured *
1736 *************************************************/
1737
1738 /* This function is called when an SMTP session ends. If the log selector
1739 smtp_no_mail is set, write a log line giving some details of what has happened
1740 in the SMTP session.
1741
1742 Arguments: none
1743 Returns: nothing
1744 */
1745
1746 void
1747 smtp_log_no_mail(void)
1748 {
1749 int i;
1750 uschar * sep, * s;
1751 gstring * g = NULL;
1752
1753 if (smtp_mailcmd_count > 0 || !LOGGING(smtp_no_mail))
1754 return;
1755
1756 if (sender_host_authenticated)
1757 {
1758 g = string_append(g, 2, US" A=", sender_host_authenticated);
1759 if (authenticated_id) g = string_append(g, 2, US":", authenticated_id);
1760 }
1761
1762 #ifdef SUPPORT_TLS
1763 g = s_tlslog(g);
1764 #endif
1765
1766 sep = smtp_connection_had[SMTP_HBUFF_SIZE-1] != SCH_NONE ? US" C=..." : US" C=";
1767
1768 for (i = smtp_ch_index; i < SMTP_HBUFF_SIZE; i++)
1769 if (smtp_connection_had[i] != SCH_NONE)
1770 {
1771 g = string_append(g, 2, sep, smtp_names[smtp_connection_had[i]]);
1772 sep = US",";
1773 }
1774
1775 for (i = 0; i < smtp_ch_index; i++)
1776 {
1777 g = string_append(g, 2, sep, smtp_names[smtp_connection_had[i]]);
1778 sep = US",";
1779 }
1780
1781 if (!(s = string_from_gstring(g))) s = US"";
1782
1783 log_write(0, LOG_MAIN, "no MAIL in %sSMTP connection from %s D=%s%s",
1784 tcp_in_fastopen ? US"TFO " : US"",
1785 host_and_ident(FALSE), string_timesince(&smtp_connection_start), s);
1786 }
1787
1788
1789 /* Return list of recent smtp commands */
1790
1791 uschar *
1792 smtp_cmd_hist(void)
1793 {
1794 int i;
1795 gstring * list = NULL;
1796 uschar * s;
1797
1798 for (i = smtp_ch_index; i < SMTP_HBUFF_SIZE; i++)
1799 if (smtp_connection_had[i] != SCH_NONE)
1800 list = string_append_listele(list, ',', smtp_names[smtp_connection_had[i]]);
1801
1802 for (i = 0; i < smtp_ch_index; i++)
1803 list = string_append_listele(list, ',', smtp_names[smtp_connection_had[i]]);
1804
1805 s = string_from_gstring(list);
1806 return s ? s : US"";
1807 }
1808
1809
1810
1811
1812 /*************************************************
1813 * Check HELO line and set sender_helo_name *
1814 *************************************************/
1815
1816 /* Check the format of a HELO line. The data for HELO/EHLO is supposed to be
1817 the domain name of the sending host, or an ip literal in square brackets. The
1818 argument is placed in sender_helo_name, which is in malloc store, because it
1819 must persist over multiple incoming messages. If helo_accept_junk is set, this
1820 host is permitted to send any old junk (needed for some broken hosts).
1821 Otherwise, helo_allow_chars can be used for rogue characters in general
1822 (typically people want to let in underscores).
1823
1824 Argument:
1825 s the data portion of the line (already past any white space)
1826
1827 Returns: TRUE or FALSE
1828 */
1829
1830 static BOOL
1831 check_helo(uschar *s)
1832 {
1833 uschar *start = s;
1834 uschar *end = s + Ustrlen(s);
1835 BOOL yield = helo_accept_junk;
1836
1837 /* Discard any previous helo name */
1838
1839 if (sender_helo_name)
1840 {
1841 store_free(sender_helo_name);
1842 sender_helo_name = NULL;
1843 }
1844
1845 /* Skip tests if junk is permitted. */
1846
1847 if (!yield)
1848
1849 /* Allow the new standard form for IPv6 address literals, namely,
1850 [IPv6:....], and because someone is bound to use it, allow an equivalent
1851 IPv4 form. Allow plain addresses as well. */
1852
1853 if (*s == '[')
1854 {
1855 if (end[-1] == ']')
1856 {
1857 end[-1] = 0;
1858 if (strncmpic(s, US"[IPv6:", 6) == 0)
1859 yield = (string_is_ip_address(s+6, NULL) == 6);
1860 else if (strncmpic(s, US"[IPv4:", 6) == 0)
1861 yield = (string_is_ip_address(s+6, NULL) == 4);
1862 else
1863 yield = (string_is_ip_address(s+1, NULL) != 0);
1864 end[-1] = ']';
1865 }
1866 }
1867
1868 /* Non-literals must be alpha, dot, hyphen, plus any non-valid chars
1869 that have been configured (usually underscore - sigh). */
1870
1871 else if (*s)
1872 for (yield = TRUE; *s; s++)
1873 if (!isalnum(*s) && *s != '.' && *s != '-' &&
1874 Ustrchr(helo_allow_chars, *s) == NULL)
1875 {
1876 yield = FALSE;
1877 break;
1878 }
1879
1880 /* Save argument if OK */
1881
1882 if (yield) sender_helo_name = string_copy_malloc(start);
1883 return yield;
1884 }
1885
1886
1887
1888
1889
1890 /*************************************************
1891 * Extract SMTP command option *
1892 *************************************************/
1893
1894 /* This function picks the next option setting off the end of smtp_cmd_data. It
1895 is called for MAIL FROM and RCPT TO commands, to pick off the optional ESMTP
1896 things that can appear there.
1897
1898 Arguments:
1899 name point this at the name
1900 value point this at the data string
1901
1902 Returns: TRUE if found an option
1903 */
1904
1905 static BOOL
1906 extract_option(uschar **name, uschar **value)
1907 {
1908 uschar *n;
1909 uschar *v = smtp_cmd_data + Ustrlen(smtp_cmd_data) - 1;
1910 while (isspace(*v)) v--;
1911 v[1] = 0;
1912 while (v > smtp_cmd_data && *v != '=' && !isspace(*v))
1913 {
1914 /* Take care to not stop at a space embedded in a quoted local-part */
1915
1916 if (*v == '"') do v--; while (*v != '"' && v > smtp_cmd_data+1);
1917 v--;
1918 }
1919
1920 n = v;
1921 if (*v == '=')
1922 {
1923 while(isalpha(n[-1])) n--;
1924 /* RFC says SP, but TAB seen in wild and other major MTAs accept it */
1925 if (!isspace(n[-1])) return FALSE;
1926 n[-1] = 0;
1927 }
1928 else
1929 {
1930 n++;
1931 if (v == smtp_cmd_data) return FALSE;
1932 }
1933 *v++ = 0;
1934 *name = n;
1935 *value = v;
1936 return TRUE;
1937 }
1938
1939
1940
1941
1942
1943 /*************************************************
1944 * Reset for new message *
1945 *************************************************/
1946
1947 /* This function is called whenever the SMTP session is reset from
1948 within either of the setup functions; also from the daemon loop.
1949
1950 Argument: the stacking pool storage reset point
1951 Returns: nothing
1952 */
1953
1954 void
1955 smtp_reset(void *reset_point)
1956 {
1957 recipients_list = NULL;
1958 rcpt_count = rcpt_defer_count = rcpt_fail_count =
1959 raw_recipients_count = recipients_count = recipients_list_max = 0;
1960 message_linecount = 0;
1961 message_size = -1;
1962 acl_added_headers = NULL;
1963 acl_removed_headers = NULL;
1964 queue_only_policy = FALSE;
1965 rcpt_smtp_response = NULL;
1966 rcpt_smtp_response_same = TRUE;
1967 rcpt_in_progress = FALSE;
1968 deliver_freeze = FALSE; /* Can be set by ACL */
1969 freeze_tell = freeze_tell_config; /* Can be set by ACL */
1970 fake_response = OK; /* Can be set by ACL */
1971 #ifdef WITH_CONTENT_SCAN
1972 no_mbox_unspool = FALSE; /* Can be set by ACL */
1973 #endif
1974 submission_mode = FALSE; /* Can be set by ACL */
1975 suppress_local_fixups = suppress_local_fixups_default; /* Can be set by ACL */
1976 active_local_from_check = local_from_check; /* Can be set by ACL */
1977 active_local_sender_retain = local_sender_retain; /* Can be set by ACL */
1978 sending_ip_address = NULL;
1979 return_path = sender_address = NULL;
1980 sender_data = NULL; /* Can be set by ACL */
1981 deliver_localpart_parent = deliver_localpart_orig = NULL;
1982 deliver_domain_parent = deliver_domain_orig = NULL;
1983 callout_address = NULL;
1984 submission_name = NULL; /* Can be set by ACL */
1985 raw_sender = NULL; /* After SMTP rewrite, before qualifying */
1986 sender_address_unrewritten = NULL; /* Set only after verify rewrite */
1987 sender_verified_list = NULL; /* No senders verified */
1988 memset(sender_address_cache, 0, sizeof(sender_address_cache));
1989 memset(sender_domain_cache, 0, sizeof(sender_domain_cache));
1990
1991 authenticated_sender = NULL;
1992 #ifdef EXPERIMENTAL_BRIGHTMAIL
1993 bmi_run = 0;
1994 bmi_verdicts = NULL;
1995 #endif
1996 dnslist_domain = dnslist_matched = NULL;
1997 #ifndef DISABLE_DKIM
1998 dkim_cur_signer = dkim_signers = NULL;
1999 dkim_disable_verify = dkim_collect_input = FALSE;
2000 #endif
2001 dsn_ret = 0;
2002 dsn_envid = NULL;
2003 deliver_host = deliver_host_address = NULL; /* Can be set by ACL */
2004 #ifndef DISABLE_PRDR
2005 prdr_requested = FALSE;
2006 #endif
2007 #ifdef SUPPORT_SPF
2008 spf_header_comment = spf_received = spf_result = spf_smtp_comment = NULL;
2009 #endif
2010 #ifdef EXPERIMENTAL_ARC
2011 arc_state = arc_state_reason = NULL;
2012 #endif
2013 #ifdef SUPPORT_I18N
2014 message_smtputf8 = FALSE;
2015 #endif
2016 body_linecount = body_zerocount = 0;
2017
2018 sender_rate = sender_rate_limit = sender_rate_period = NULL;
2019 ratelimiters_mail = NULL; /* Updated by ratelimit ACL condition */
2020 /* Note that ratelimiters_conn persists across resets. */
2021
2022 /* Reset message ACL variables */
2023
2024 acl_var_m = NULL;
2025
2026 /* The message body variables use malloc store. They may be set if this is
2027 not the first message in an SMTP session and the previous message caused them
2028 to be referenced in an ACL. */
2029
2030 if (message_body)
2031 {
2032 store_free(message_body);
2033 message_body = NULL;
2034 }
2035
2036 if (message_body_end)
2037 {
2038 store_free(message_body_end);
2039 message_body_end = NULL;
2040 }
2041
2042 /* Warning log messages are also saved in malloc store. They are saved to avoid
2043 repetition in the same message, but it seems right to repeat them for different
2044 messages. */
2045
2046 while (acl_warn_logged)
2047 {
2048 string_item *this = acl_warn_logged;
2049 acl_warn_logged = acl_warn_logged->next;
2050 store_free(this);
2051 }
2052 store_reset(reset_point);
2053 }
2054
2055
2056
2057
2058
2059 /*************************************************
2060 * Initialize for incoming batched SMTP message *
2061 *************************************************/
2062
2063 /* This function is called from smtp_setup_msg() in the case when
2064 smtp_batched_input is true. This happens when -bS is used to pass a whole batch
2065 of messages in one file with SMTP commands between them. All errors must be
2066 reported by sending a message, and only MAIL FROM, RCPT TO, and DATA are
2067 relevant. After an error on a sender, or an invalid recipient, the remainder
2068 of the message is skipped. The value of received_protocol is already set.
2069
2070 Argument: none
2071 Returns: > 0 message successfully started (reached DATA)
2072 = 0 QUIT read or end of file reached
2073 < 0 should not occur
2074 */
2075
2076 static int
2077 smtp_setup_batch_msg(void)
2078 {
2079 int done = 0;
2080 void *reset_point = store_get(0);
2081
2082 /* Save the line count at the start of each transaction - single commands
2083 like HELO and RSET count as whole transactions. */
2084
2085 bsmtp_transaction_linecount = receive_linecount;
2086
2087 if ((receive_feof)()) return 0; /* Treat EOF as QUIT */
2088
2089 cancel_cutthrough_connection(TRUE, US"smtp_setup_batch_msg");
2090 smtp_reset(reset_point); /* Reset for start of message */
2091
2092 /* Deal with SMTP commands. This loop is exited by setting done to a POSITIVE
2093 value. The values are 2 larger than the required yield of the function. */
2094
2095 while (done <= 0)
2096 {
2097 uschar *errmess;
2098 uschar *recipient = NULL;
2099 int start, end, sender_domain, recipient_domain;
2100
2101 switch(smtp_read_command(FALSE, GETC_BUFFER_UNLIMITED))
2102 {
2103 /* The HELO/EHLO commands set sender_address_helo if they have
2104 valid data; otherwise they are ignored, except that they do
2105 a reset of the state. */
2106
2107 case HELO_CMD:
2108 case EHLO_CMD:
2109
2110 check_helo(smtp_cmd_data);
2111 /* Fall through */
2112
2113 case RSET_CMD:
2114 cancel_cutthrough_connection(TRUE, US"RSET received");
2115 smtp_reset(reset_point);
2116 bsmtp_transaction_linecount = receive_linecount;
2117 break;
2118
2119
2120 /* The MAIL FROM command requires an address as an operand. All we
2121 do here is to parse it for syntactic correctness. The form "<>" is
2122 a special case which converts into an empty string. The start/end
2123 pointers in the original are not used further for this address, as
2124 it is the canonical extracted address which is all that is kept. */
2125
2126 case MAIL_CMD:
2127 smtp_mailcmd_count++; /* Count for no-mail log */
2128 if (sender_address != NULL)
2129 /* The function moan_smtp_batch() does not return. */
2130 moan_smtp_batch(smtp_cmd_buffer, "503 Sender already given");
2131
2132 if (smtp_cmd_data[0] == 0)
2133 /* The function moan_smtp_batch() does not return. */
2134 moan_smtp_batch(smtp_cmd_buffer, "501 MAIL FROM must have an address operand");
2135
2136 /* Reset to start of message */
2137
2138 cancel_cutthrough_connection(TRUE, US"MAIL received");
2139 smtp_reset(reset_point);
2140
2141 /* Apply SMTP rewrite */
2142
2143 raw_sender = ((rewrite_existflags & rewrite_smtp) != 0)?
2144 rewrite_one(smtp_cmd_data, rewrite_smtp|rewrite_smtp_sender, NULL, FALSE,
2145 US"", global_rewrite_rules) : smtp_cmd_data;
2146
2147 /* Extract the address; the TRUE flag allows <> as valid */
2148
2149 raw_sender =
2150 parse_extract_address(raw_sender, &errmess, &start, &end, &sender_domain,
2151 TRUE);
2152
2153 if (!raw_sender)
2154 /* The function moan_smtp_batch() does not return. */
2155 moan_smtp_batch(smtp_cmd_buffer, "501 %s", errmess);
2156
2157 sender_address = string_copy(raw_sender);
2158
2159 /* Qualify unqualified sender addresses if permitted to do so. */
2160
2161 if ( !sender_domain
2162 && sender_address[0] != 0 && sender_address[0] != '@')
2163 if (allow_unqualified_sender)
2164 {
2165 sender_address = rewrite_address_qualify(sender_address, FALSE);
2166 DEBUG(D_receive) debug_printf("unqualified address %s accepted "
2167 "and rewritten\n", raw_sender);
2168 }
2169 /* The function moan_smtp_batch() does not return. */
2170 else
2171 moan_smtp_batch(smtp_cmd_buffer, "501 sender address must contain "
2172 "a domain");
2173 break;
2174
2175
2176 /* The RCPT TO command requires an address as an operand. All we do
2177 here is to parse it for syntactic correctness. There may be any number
2178 of RCPT TO commands, specifying multiple senders. We build them all into
2179 a data structure that is in argc/argv format. The start/end values
2180 given by parse_extract_address are not used, as we keep only the
2181 extracted address. */
2182
2183 case RCPT_CMD:
2184 if (!sender_address)
2185 /* The function moan_smtp_batch() does not return. */
2186 moan_smtp_batch(smtp_cmd_buffer, "503 No sender yet given");
2187
2188 if (smtp_cmd_data[0] == 0)
2189 /* The function moan_smtp_batch() does not return. */
2190 moan_smtp_batch(smtp_cmd_buffer,
2191 "501 RCPT TO must have an address operand");
2192
2193 /* Check maximum number allowed */
2194
2195 if (recipients_max > 0 && recipients_count + 1 > recipients_max)
2196 /* The function moan_smtp_batch() does not return. */
2197 moan_smtp_batch(smtp_cmd_buffer, "%s too many recipients",
2198 recipients_max_reject? "552": "452");
2199
2200 /* Apply SMTP rewrite, then extract address. Don't allow "<>" as a
2201 recipient address */
2202
2203 recipient = rewrite_existflags & rewrite_smtp
2204 ? rewrite_one(smtp_cmd_data, rewrite_smtp, NULL, FALSE, US"",
2205 global_rewrite_rules)
2206 : smtp_cmd_data;
2207
2208 recipient = parse_extract_address(recipient, &errmess, &start, &end,
2209 &recipient_domain, FALSE);
2210
2211 if (!recipient)
2212 /* The function moan_smtp_batch() does not return. */
2213 moan_smtp_batch(smtp_cmd_buffer, "501 %s", errmess);
2214
2215 /* If the recipient address is unqualified, qualify it if permitted. Then
2216 add it to the list of recipients. */
2217
2218 if (!recipient_domain)
2219 if (allow_unqualified_recipient)
2220 {
2221 DEBUG(D_receive) debug_printf("unqualified address %s accepted\n",
2222 recipient);
2223 recipient = rewrite_address_qualify(recipient, TRUE);
2224 }
2225 /* The function moan_smtp_batch() does not return. */
2226 else
2227 moan_smtp_batch(smtp_cmd_buffer,
2228 "501 recipient address must contain a domain");
2229
2230 receive_add_recipient(recipient, -1);
2231 break;
2232
2233
2234 /* The DATA command is legal only if it follows successful MAIL FROM
2235 and RCPT TO commands. This function is complete when a valid DATA
2236 command is encountered. */
2237
2238 case DATA_CMD:
2239 if (!sender_address || recipients_count <= 0)
2240 /* The function moan_smtp_batch() does not return. */
2241 if (!sender_address)
2242 moan_smtp_batch(smtp_cmd_buffer,
2243 "503 MAIL FROM:<sender> command must precede DATA");
2244 else
2245 moan_smtp_batch(smtp_cmd_buffer,
2246 "503 RCPT TO:<recipient> must precede DATA");
2247 else
2248 {
2249 done = 3; /* DATA successfully achieved */
2250 message_ended = END_NOTENDED; /* Indicate in middle of message */
2251 }
2252 break;
2253
2254
2255 /* The VRFY, EXPN, HELP, ETRN, and NOOP commands are ignored. */
2256
2257 case VRFY_CMD:
2258 case EXPN_CMD:
2259 case HELP_CMD:
2260 case NOOP_CMD:
2261 case ETRN_CMD:
2262 bsmtp_transaction_linecount = receive_linecount;
2263 break;
2264
2265
2266 case EOF_CMD:
2267 case QUIT_CMD:
2268 done = 2;
2269 break;
2270
2271
2272 case BADARG_CMD:
2273 /* The function moan_smtp_batch() does not return. */
2274 moan_smtp_batch(smtp_cmd_buffer, "501 Unexpected argument data");
2275 break;
2276
2277
2278 case BADCHAR_CMD:
2279 /* The function moan_smtp_batch() does not return. */
2280 moan_smtp_batch(smtp_cmd_buffer, "501 Unexpected NULL in SMTP command");
2281 break;
2282
2283
2284 default:
2285 /* The function moan_smtp_batch() does not return. */
2286 moan_smtp_batch(smtp_cmd_buffer, "500 Command unrecognized");
2287 break;
2288 }
2289 }
2290
2291 return done - 2; /* Convert yield values */
2292 }
2293
2294
2295
2296
2297 static BOOL
2298 smtp_log_tls_fail(uschar * errstr)
2299 {
2300 uschar * conn_info = smtp_get_connection_info();
2301
2302 if (Ustrncmp(conn_info, US"SMTP ", 5) == 0) conn_info += 5;
2303 /* I'd like to get separated H= here, but too hard for now */
2304
2305 log_write(0, LOG_MAIN, "TLS error on %s %s", conn_info, errstr);
2306 return FALSE;
2307 }
2308
2309
2310
2311
2312 #ifdef TCP_FASTOPEN
2313 static void
2314 tfo_in_check(void)
2315 {
2316 # ifdef TCP_INFO
2317 struct tcp_info tinfo;
2318 socklen_t len = sizeof(tinfo);
2319
2320 if ( getsockopt(fileno(smtp_out), IPPROTO_TCP, TCP_INFO, &tinfo, &len) == 0
2321 && tinfo.tcpi_state == TCP_SYN_RECV
2322 )
2323 {
2324 DEBUG(D_receive) debug_printf("TCP_FASTOPEN mode connection (state TCP_SYN_RECV)\n");
2325 tcp_in_fastopen = TRUE;
2326 }
2327 # endif
2328 }
2329 #endif
2330
2331
2332 /*************************************************
2333 * Start an SMTP session *
2334 *************************************************/
2335
2336 /* This function is called at the start of an SMTP session. Thereafter,
2337 smtp_setup_msg() is called to initiate each separate message. This
2338 function does host-specific testing, and outputs the banner line.
2339
2340 Arguments: none
2341 Returns: FALSE if the session can not continue; something has
2342 gone wrong, or the connection to the host is blocked
2343 */
2344
2345 BOOL
2346 smtp_start_session(void)
2347 {
2348 int esclen;
2349 uschar *user_msg, *log_msg;
2350 uschar *code, *esc;
2351 uschar *p, *s;
2352 gstring * ss;
2353
2354 gettimeofday(&smtp_connection_start, NULL);
2355 for (smtp_ch_index = 0; smtp_ch_index < SMTP_HBUFF_SIZE; smtp_ch_index++)
2356 smtp_connection_had[smtp_ch_index] = SCH_NONE;
2357 smtp_ch_index = 0;
2358
2359 /* Default values for certain variables */
2360
2361 helo_seen = esmtp = helo_accept_junk = FALSE;
2362 smtp_mailcmd_count = 0;
2363 count_nonmail = TRUE_UNSET;
2364 synprot_error_count = unknown_command_count = nonmail_command_count = 0;
2365 smtp_delay_mail = smtp_rlm_base;
2366 auth_advertised = FALSE;
2367 pipelining_advertised = FALSE;
2368 pipelining_enable = TRUE;
2369 sync_cmd_limit = NON_SYNC_CMD_NON_PIPELINING;
2370 smtp_exit_function_called = FALSE; /* For avoiding loop in not-quit exit */
2371
2372 /* If receiving by -bs from a trusted user, or testing with -bh, we allow
2373 authentication settings from -oMaa to remain in force. */
2374
2375 if (!host_checking && !sender_host_notsocket)
2376 sender_host_auth_pubname = sender_host_authenticated = NULL;
2377 authenticated_by = NULL;
2378
2379 #ifdef SUPPORT_TLS
2380 tls_in.cipher = tls_in.peerdn = NULL;
2381 tls_in.ourcert = tls_in.peercert = NULL;
2382 tls_in.sni = NULL;
2383 tls_in.ocsp = OCSP_NOT_REQ;
2384 tls_advertised = FALSE;
2385 #endif
2386 dsn_advertised = FALSE;
2387 #ifdef SUPPORT_I18N
2388 smtputf8_advertised = FALSE;
2389 #endif
2390
2391 /* Reset ACL connection variables */
2392
2393 acl_var_c = NULL;
2394
2395 /* Allow for trailing 0 in the command and data buffers. */
2396
2397 if (!(smtp_cmd_buffer = US malloc(2*SMTP_CMD_BUFFER_SIZE + 2)))
2398 log_write(0, LOG_MAIN|LOG_PANIC_DIE,
2399 "malloc() failed for SMTP command buffer");
2400
2401 smtp_cmd_buffer[0] = 0;
2402 smtp_data_buffer = smtp_cmd_buffer + SMTP_CMD_BUFFER_SIZE + 1;
2403
2404 /* For batched input, the protocol setting can be overridden from the
2405 command line by a trusted caller. */
2406
2407 if (smtp_batched_input)
2408 {
2409 if (!received_protocol) received_protocol = US"local-bsmtp";
2410 }
2411
2412 /* For non-batched SMTP input, the protocol setting is forced here. It will be
2413 reset later if any of EHLO/AUTH/STARTTLS are received. */
2414
2415 else
2416 received_protocol =
2417 (sender_host_address ? protocols : protocols_local) [pnormal];
2418
2419 /* Set up the buffer for inputting using direct read() calls, and arrange to
2420 call the local functions instead of the standard C ones. Place a NUL at the
2421 end of the buffer to safety-stop C-string reads from it. */
2422
2423 if (!(smtp_inbuffer = US malloc(IN_BUFFER_SIZE)))
2424 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "malloc() failed for SMTP input buffer");
2425 smtp_inbuffer[IN_BUFFER_SIZE-1] = '\0';
2426
2427 receive_getc = smtp_getc;
2428 receive_getbuf = smtp_getbuf;
2429 receive_get_cache = smtp_get_cache;
2430 receive_ungetc = smtp_ungetc;
2431 receive_feof = smtp_feof;
2432 receive_ferror = smtp_ferror;
2433 receive_smtp_buffered = smtp_buffered;
2434 smtp_inptr = smtp_inend = smtp_inbuffer;
2435 smtp_had_eof = smtp_had_error = 0;
2436
2437 /* Set up the message size limit; this may be host-specific */
2438
2439 thismessage_size_limit = expand_string_integer(message_size_limit, TRUE);
2440 if (expand_string_message)
2441 {
2442 if (thismessage_size_limit == -1)
2443 log_write(0, LOG_MAIN|LOG_PANIC, "unable to expand message_size_limit: "
2444 "%s", expand_string_message);
2445 else
2446 log_write(0, LOG_MAIN|LOG_PANIC, "invalid message_size_limit: "
2447 "%s", expand_string_message);
2448 smtp_closedown(US"Temporary local problem - please try later");
2449 return FALSE;
2450 }
2451
2452 /* When a message is input locally via the -bs or -bS options, sender_host_
2453 unknown is set unless -oMa was used to force an IP address, in which case it
2454 is checked like a real remote connection. When -bs is used from inetd, this
2455 flag is not set, causing the sending host to be checked. The code that deals
2456 with IP source routing (if configured) is never required for -bs or -bS and
2457 the flag sender_host_notsocket is used to suppress it.
2458
2459 If smtp_accept_max and smtp_accept_reserve are set, keep some connections in
2460 reserve for certain hosts and/or networks. */
2461
2462 if (!sender_host_unknown)
2463 {
2464 int rc;
2465 BOOL reserved_host = FALSE;
2466
2467 /* Look up IP options (source routing info) on the socket if this is not an
2468 -oMa "host", and if any are found, log them and drop the connection.
2469
2470 Linux (and others now, see below) is different to everyone else, so there
2471 has to be some conditional compilation here. Versions of Linux before 2.1.15
2472 used a structure whose name was "options". Somebody finally realized that
2473 this name was silly, and it got changed to "ip_options". I use the
2474 newer name here, but there is a fudge in the script that sets up os.h
2475 to define a macro in older Linux systems.
2476
2477 Sigh. Linux is a fast-moving target. Another generation of Linux uses
2478 glibc 2, which has chosen ip_opts for the structure name. This is now
2479 really a glibc thing rather than a Linux thing, so the condition name
2480 has been changed to reflect this. It is relevant also to GNU/Hurd.
2481
2482 Mac OS 10.x (Darwin) is like the later glibc versions, but without the
2483 setting of the __GLIBC__ macro, so we can't detect it automatically. There's
2484 a special macro defined in the os.h file.
2485
2486 Some DGUX versions on older hardware appear not to support IP options at
2487 all, so there is now a general macro which can be set to cut out this
2488 support altogether.
2489
2490 How to do this properly in IPv6 is not yet known. */
2491
2492 #if !HAVE_IPV6 && !defined(NO_IP_OPTIONS)
2493
2494 #ifdef GLIBC_IP_OPTIONS
2495 #if (!defined __GLIBC__) || (__GLIBC__ < 2)
2496 #define OPTSTYLE 1
2497 #else
2498 #define OPTSTYLE 2
2499 #endif
2500 #elif defined DARWIN_IP_OPTIONS
2501 #define OPTSTYLE 2
2502 #else
2503 #define OPTSTYLE 3
2504 #endif
2505
2506 if (!host_checking && !sender_host_notsocket)
2507 {
2508 #if OPTSTYLE == 1
2509 EXIM_SOCKLEN_T optlen = sizeof(struct ip_options) + MAX_IPOPTLEN;
2510 struct ip_options *ipopt = store_get(optlen);
2511 #elif OPTSTYLE == 2
2512 struct ip_opts ipoptblock;
2513 struct ip_opts *ipopt = &ipoptblock;
2514 EXIM_SOCKLEN_T optlen = sizeof(ipoptblock);
2515 #else
2516 struct ipoption ipoptblock;
2517 struct ipoption *ipopt = &ipoptblock;
2518 EXIM_SOCKLEN_T optlen = sizeof(ipoptblock);
2519 #endif
2520
2521 /* Occasional genuine failures of getsockopt() have been seen - for
2522 example, "reset by peer". Therefore, just log and give up on this
2523 call, unless the error is ENOPROTOOPT. This error is given by systems
2524 that have the interfaces but not the mechanism - e.g. GNU/Hurd at the time
2525 of writing. So for that error, carry on - we just can't do an IP options
2526 check. */
2527
2528 DEBUG(D_receive) debug_printf("checking for IP options\n");
2529
2530 if (getsockopt(fileno(smtp_out), IPPROTO_IP, IP_OPTIONS, US (ipopt),
2531 &optlen) < 0)
2532 {
2533 if (errno != ENOPROTOOPT)
2534 {
2535 log_write(0, LOG_MAIN, "getsockopt() failed from %s: %s",
2536 host_and_ident(FALSE), strerror(errno));
2537 smtp_printf("451 SMTP service not available\r\n", FALSE);
2538 return FALSE;
2539 }
2540 }
2541
2542 /* Deal with any IP options that are set. On the systems I have looked at,
2543 the value of MAX_IPOPTLEN has been 40, meaning that there should never be
2544 more logging data than will fit in big_buffer. Nevertheless, after somebody
2545 questioned this code, I've added in some paranoid checking. */
2546
2547 else if (optlen > 0)
2548 {
2549 uschar *p = big_buffer;
2550 uschar *pend = big_buffer + big_buffer_size;
2551 uschar *opt, *adptr;
2552 int optcount;
2553 struct in_addr addr;
2554
2555 #if OPTSTYLE == 1
2556 uschar *optstart = US (ipopt->__data);
2557 #elif OPTSTYLE == 2
2558 uschar *optstart = US (ipopt->ip_opts);
2559 #else
2560 uschar *optstart = US (ipopt->ipopt_list);
2561 #endif
2562
2563 DEBUG(D_receive) debug_printf("IP options exist\n");
2564
2565 Ustrcpy(p, "IP options on incoming call:");
2566 p += Ustrlen(p);
2567
2568 for (opt = optstart; opt != NULL &&
2569 opt < US (ipopt) + optlen;)
2570 {
2571 switch (*opt)
2572 {
2573 case IPOPT_EOL:
2574 opt = NULL;
2575 break;
2576
2577 case IPOPT_NOP:
2578 opt++;
2579 break;
2580
2581 case IPOPT_SSRR:
2582 case IPOPT_LSRR:
2583 if (!string_format(p, pend-p, " %s [@%s",
2584 (*opt == IPOPT_SSRR)? "SSRR" : "LSRR",
2585 #if OPTSTYLE == 1
2586 inet_ntoa(*((struct in_addr *)(&(ipopt->faddr))))))
2587 #elif OPTSTYLE == 2
2588 inet_ntoa(ipopt->ip_dst)))
2589 #else
2590 inet_ntoa(ipopt->ipopt_dst)))
2591 #endif
2592 {
2593 opt = NULL;
2594 break;
2595 }
2596
2597 p += Ustrlen(p);
2598 optcount = (opt[1] - 3) / sizeof(struct in_addr);
2599 adptr = opt + 3;
2600 while (optcount-- > 0)
2601 {
2602 memcpy(&addr, adptr, sizeof(addr));
2603 if (!string_format(p, pend - p - 1, "%s%s",
2604 (optcount == 0)? ":" : "@", inet_ntoa(addr)))
2605 {
2606 opt = NULL;
2607 break;
2608 }
2609 p += Ustrlen(p);
2610 adptr += sizeof(struct in_addr);
2611 }
2612 *p++ = ']';
2613 opt += opt[1];
2614 break;
2615
2616 default:
2617 {
2618 int i;
2619 if (pend - p < 4 + 3*opt[1]) { opt = NULL; break; }
2620 Ustrcat(p, "[ ");
2621 p += 2;
2622 for (i = 0; i < opt[1]; i++)
2623 p += sprintf(CS p, "%2.2x ", opt[i]);
2624 *p++ = ']';
2625 }
2626 opt += opt[1];
2627 break;
2628 }
2629 }
2630
2631 *p = 0;
2632 log_write(0, LOG_MAIN, "%s", big_buffer);
2633
2634 /* Refuse any call with IP options. This is what tcpwrappers 7.5 does. */
2635
2636 log_write(0, LOG_MAIN|LOG_REJECT,
2637 "connection from %s refused (IP options)", host_and_ident(FALSE));
2638
2639 smtp_printf("554 SMTP service not available\r\n", FALSE);
2640 return FALSE;
2641 }
2642
2643 /* Length of options = 0 => there are no options */
2644
2645 else DEBUG(D_receive) debug_printf("no IP options found\n");
2646 }
2647 #endif /* HAVE_IPV6 && !defined(NO_IP_OPTIONS) */
2648
2649 /* Set keep-alive in socket options. The option is on by default. This
2650 setting is an attempt to get rid of some hanging connections that stick in
2651 read() when the remote end (usually a dialup) goes away. */
2652
2653 if (smtp_accept_keepalive && !sender_host_notsocket)
2654 ip_keepalive(fileno(smtp_out), sender_host_address, FALSE);
2655
2656 /* If the current host matches host_lookup, set the name by doing a
2657 reverse lookup. On failure, sender_host_name will be NULL and
2658 host_lookup_failed will be TRUE. This may or may not be serious - optional
2659 checks later. */
2660
2661 if (verify_check_host(&host_lookup) == OK)
2662 {
2663 (void)host_name_lookup();
2664 host_build_sender_fullhost();
2665 }
2666
2667 /* Delay this until we have the full name, if it is looked up. */
2668
2669 set_process_info("handling incoming connection from %s",
2670 host_and_ident(FALSE));
2671
2672 /* Expand smtp_receive_timeout, if needed */
2673
2674 if (smtp_receive_timeout_s)
2675 {
2676 uschar * exp;
2677 if ( !(exp = expand_string(smtp_receive_timeout_s))
2678 || !(*exp)
2679 || (smtp_receive_timeout = readconf_readtime(exp, 0, FALSE)) < 0
2680 )
2681 log_write(0, LOG_MAIN|LOG_PANIC,
2682 "bad value for smtp_receive_timeout: '%s'", exp ? exp : US"");
2683 }
2684
2685 /* Test for explicit connection rejection */
2686
2687 if (verify_check_host(&host_reject_connection) == OK)
2688 {
2689 log_write(L_connection_reject, LOG_MAIN|LOG_REJECT, "refused connection "
2690 "from %s (host_reject_connection)", host_and_ident(FALSE));
2691 smtp_printf("554 SMTP service not available\r\n", FALSE);
2692 return FALSE;
2693 }
2694
2695 /* Test with TCP Wrappers if so configured. There is a problem in that
2696 hosts_ctl() returns 0 (deny) under a number of system failure circumstances,
2697 such as disks dying. In these cases, it is desirable to reject with a 4xx
2698 error instead of a 5xx error. There isn't a "right" way to detect such
2699 problems. The following kludge is used: errno is zeroed before calling
2700 hosts_ctl(). If the result is "reject", a 5xx error is given only if the
2701 value of errno is 0 or ENOENT (which happens if /etc/hosts.{allow,deny} does
2702 not exist). */
2703
2704 #ifdef USE_TCP_WRAPPERS
2705 errno = 0;
2706 if (!(tcp_wrappers_name = expand_string(tcp_wrappers_daemon_name)))
2707 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "Expansion of \"%s\" "
2708 "(tcp_wrappers_name) failed: %s", string_printing(tcp_wrappers_name),
2709 expand_string_message);
2710
2711 if (!hosts_ctl(tcp_wrappers_name,
2712 sender_host_name ? CS sender_host_name : STRING_UNKNOWN,
2713 sender_host_address ? CS sender_host_address : STRING_UNKNOWN,
2714 sender_ident ? CS sender_ident : STRING_UNKNOWN))
2715 {
2716 if (errno == 0 || errno == ENOENT)
2717 {
2718 HDEBUG(D_receive) debug_printf("tcp wrappers rejection\n");
2719 log_write(L_connection_reject,
2720 LOG_MAIN|LOG_REJECT, "refused connection from %s "
2721 "(tcp wrappers)", host_and_ident(FALSE));
2722 smtp_printf("554 SMTP service not available\r\n", FALSE);
2723 }
2724 else
2725 {
2726 int save_errno = errno;
2727 HDEBUG(D_receive) debug_printf("tcp wrappers rejected with unexpected "
2728 "errno value %d\n", save_errno);
2729 log_write(L_connection_reject,
2730 LOG_MAIN|LOG_REJECT, "temporarily refused connection from %s "
2731 "(tcp wrappers errno=%d)", host_and_ident(FALSE), save_errno);
2732 smtp_printf("451 Temporary local problem - please try later\r\n", FALSE);
2733 }
2734 return FALSE;
2735 }
2736 #endif
2737
2738 /* Check for reserved slots. The value of smtp_accept_count has already been
2739 incremented to include this process. */
2740
2741 if (smtp_accept_max > 0 &&
2742 smtp_accept_count > smtp_accept_max - smtp_accept_reserve)
2743 {
2744 if ((rc = verify_check_host(&smtp_reserve_hosts)) != OK)
2745 {
2746 log_write(L_connection_reject,
2747 LOG_MAIN, "temporarily refused connection from %s: not in "
2748 "reserve list: connected=%d max=%d reserve=%d%s",
2749 host_and_ident(FALSE), smtp_accept_count - 1, smtp_accept_max,
2750 smtp_accept_reserve, (rc == DEFER)? " (lookup deferred)" : "");
2751 smtp_printf("421 %s: Too many concurrent SMTP connections; "
2752 "please try again later\r\n", FALSE, smtp_active_hostname);
2753 return FALSE;
2754 }
2755 reserved_host = TRUE;
2756 }
2757
2758 /* If a load level above which only messages from reserved hosts are
2759 accepted is set, check the load. For incoming calls via the daemon, the
2760 check is done in the superior process if there are no reserved hosts, to
2761 save a fork. In all cases, the load average will already be available
2762 in a global variable at this point. */
2763
2764 if (smtp_load_reserve >= 0 &&
2765 load_average > smtp_load_reserve &&
2766 !reserved_host &&
2767 verify_check_host(&smtp_reserve_hosts) != OK)
2768 {
2769 log_write(L_connection_reject,
2770 LOG_MAIN, "temporarily refused connection from %s: not in "
2771 "reserve list and load average = %.2f", host_and_ident(FALSE),
2772 (double)load_average/1000.0);
2773 smtp_printf("421 %s: Too much load; please try again later\r\n", FALSE,
2774 smtp_active_hostname);
2775 return FALSE;
2776 }
2777
2778 /* Determine whether unqualified senders or recipients are permitted
2779 for this host. Unfortunately, we have to do this every time, in order to
2780 set the flags so that they can be inspected when considering qualifying
2781 addresses in the headers. For a site that permits no qualification, this
2782 won't take long, however. */
2783
2784 allow_unqualified_sender =
2785 verify_check_host(&sender_unqualified_hosts) == OK;
2786
2787 allow_unqualified_recipient =
2788 verify_check_host(&recipient_unqualified_hosts) == OK;
2789
2790 /* Determine whether HELO/EHLO is required for this host. The requirement
2791 can be hard or soft. */
2792
2793 helo_required = verify_check_host(&helo_verify_hosts) == OK;
2794 if (!helo_required)
2795 helo_verify = verify_check_host(&helo_try_verify_hosts) == OK;
2796
2797 /* Determine whether this hosts is permitted to send syntactic junk
2798 after a HELO or EHLO command. */
2799
2800 helo_accept_junk = verify_check_host(&helo_accept_junk_hosts) == OK;
2801 }
2802
2803 /* For batch SMTP input we are now done. */
2804
2805 if (smtp_batched_input) return TRUE;
2806
2807 /* If valid Proxy Protocol source is connecting, set up session.
2808 * Failure will not allow any SMTP function other than QUIT. */
2809
2810 #ifdef SUPPORT_PROXY
2811 proxy_session = FALSE;
2812 proxy_session_failed = FALSE;
2813 if (check_proxy_protocol_host())
2814 setup_proxy_protocol_host();
2815 #endif
2816
2817 /* Start up TLS if tls_on_connect is set. This is for supporting the legacy
2818 smtps port for use with older style SSL MTAs. */
2819
2820 #ifdef SUPPORT_TLS
2821 if (tls_in.on_connect)
2822 {
2823 if (tls_server_start(tls_require_ciphers, &user_msg) != OK)
2824 return smtp_log_tls_fail(user_msg);
2825 cmd_list[CMD_LIST_TLS_AUTH].is_mail_cmd = TRUE;
2826 }
2827 #endif
2828
2829 /* Run the connect ACL if it exists */
2830
2831 user_msg = NULL;
2832 if (acl_smtp_connect)
2833 {
2834 int rc;
2835 if ((rc = acl_check(ACL_WHERE_CONNECT, NULL, acl_smtp_connect, &user_msg,
2836 &log_msg)) != OK)
2837 {
2838 (void) smtp_handle_acl_fail(ACL_WHERE_CONNECT, rc, user_msg, log_msg);
2839 return FALSE;
2840 }
2841 }
2842
2843 /* Output the initial message for a two-way SMTP connection. It may contain
2844 newlines, which then cause a multi-line response to be given. */
2845
2846 code = US"220"; /* Default status code */
2847 esc = US""; /* Default extended status code */
2848 esclen = 0; /* Length of esc */
2849
2850 if (!user_msg)
2851 {
2852 if (!(s = expand_string(smtp_banner)))
2853 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "Expansion of \"%s\" (smtp_banner) "
2854 "failed: %s", smtp_banner, expand_string_message);
2855 }
2856 else
2857 {
2858 int codelen = 3;
2859 s = user_msg;
2860 smtp_message_code(&code, &codelen, &s, NULL, TRUE);
2861 if (codelen > 4)
2862 {
2863 esc = code + 4;
2864 esclen = codelen - 4;
2865 }
2866 }
2867
2868 /* Remove any terminating newlines; might as well remove trailing space too */
2869
2870 p = s + Ustrlen(s);
2871 while (p > s && isspace(p[-1])) p--;
2872 *p = 0;
2873
2874 /* It seems that CC:Mail is braindead, and assumes that the greeting message
2875 is all contained in a single IP packet. The original code wrote out the
2876 greeting using several calls to fprint/fputc, and on busy servers this could
2877 cause it to be split over more than one packet - which caused CC:Mail to fall
2878 over when it got the second part of the greeting after sending its first
2879 command. Sigh. To try to avoid this, build the complete greeting message
2880 first, and output it in one fell swoop. This gives a better chance of it
2881 ending up as a single packet. */
2882
2883 ss = string_get(256);
2884
2885 p = s;
2886 do /* At least once, in case we have an empty string */
2887 {
2888 int len;
2889 uschar *linebreak = Ustrchr(p, '\n');
2890 ss = string_catn(ss, code, 3);
2891 if (!linebreak)
2892 {
2893 len = Ustrlen(p);
2894 ss = string_catn(ss, US" ", 1);
2895 }
2896 else
2897 {
2898 len = linebreak - p;
2899 ss = string_catn(ss, US"-", 1);
2900 }
2901 ss = string_catn(ss, esc, esclen);
2902 ss = string_catn(ss, p, len);
2903 ss = string_catn(ss, US"\r\n", 2);
2904 p += len;
2905 if (linebreak) p++;
2906 }
2907 while (*p);
2908
2909 /* Before we write the banner, check that there is no input pending, unless
2910 this synchronisation check is disabled. */
2911
2912 if (!check_sync())
2913 {
2914 unsigned n = smtp_inend - smtp_inptr;
2915 if (n > 32) n = 32;
2916
2917 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP protocol "
2918 "synchronization error (input sent without waiting for greeting): "
2919 "rejected connection from %s input=\"%s\"", host_and_ident(TRUE),
2920 string_printing(string_copyn(smtp_inptr, n)));
2921 smtp_printf("554 SMTP synchronization error\r\n", FALSE);
2922 return FALSE;
2923 }
2924
2925 /* Now output the banner */
2926
2927 smtp_printf("%s", FALSE, string_from_gstring(ss));
2928
2929 /* Attempt to see if we sent the banner before the last ACK of the 3-way
2930 handshake arrived. If so we must have managed a TFO. */
2931
2932 #ifdef TCP_FASTOPEN
2933 tfo_in_check();
2934 #endif
2935
2936 return TRUE;
2937 }
2938
2939
2940
2941
2942
2943 /*************************************************
2944 * Handle SMTP syntax and protocol errors *
2945 *************************************************/
2946
2947 /* Write to the log for SMTP syntax errors in incoming commands, if configured
2948 to do so. Then transmit the error response. The return value depends on the
2949 number of syntax and protocol errors in this SMTP session.
2950
2951 Arguments:
2952 type error type, given as a log flag bit
2953 code response code; <= 0 means don't send a response
2954 data data to reflect in the response (can be NULL)
2955 errmess the error message
2956
2957 Returns: -1 limit of syntax/protocol errors NOT exceeded
2958 +1 limit of syntax/protocol errors IS exceeded
2959
2960 These values fit in with the values of the "done" variable in the main
2961 processing loop in smtp_setup_msg(). */
2962
2963 static int
2964 synprot_error(int type, int code, uschar *data, uschar *errmess)
2965 {
2966 int yield = -1;
2967
2968 log_write(type, LOG_MAIN, "SMTP %s error in \"%s\" %s %s",
2969 (type == L_smtp_syntax_error)? "syntax" : "protocol",
2970 string_printing(smtp_cmd_buffer), host_and_ident(TRUE), errmess);
2971
2972 if (++synprot_error_count > smtp_max_synprot_errors)
2973 {
2974 yield = 1;
2975 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
2976 "syntax or protocol errors (last command was \"%s\")",
2977 host_and_ident(FALSE), string_printing(smtp_cmd_buffer));
2978 }
2979
2980 if (code > 0)
2981 {
2982 smtp_printf("%d%c%s%s%s\r\n", FALSE, code, yield == 1 ? '-' : ' ',
2983 data ? data : US"", data ? US": " : US"", errmess);
2984 if (yield == 1)
2985 smtp_printf("%d Too many syntax or protocol errors\r\n", FALSE, code);
2986 }
2987
2988 return yield;
2989 }
2990
2991
2992
2993
2994 /*************************************************
2995 * Send SMTP response, possibly multiline *
2996 *************************************************/
2997
2998 /* There are, it seems, broken clients out there that cannot handle multiline
2999 responses. If no_multiline_responses is TRUE (it can be set from an ACL), we
3000 output nothing for non-final calls, and only the first line for anything else.
3001
3002 Arguments:
3003 code SMTP code, may involve extended status codes
3004 codelen length of smtp code; if > 4 there's an ESC
3005 final FALSE if the last line isn't the final line
3006 msg message text, possibly containing newlines
3007
3008 Returns: nothing
3009 */
3010
3011 void
3012 smtp_respond(uschar* code, int codelen, BOOL final, uschar *msg)
3013 {
3014 int esclen = 0;
3015 uschar *esc = US"";
3016
3017 if (!final && no_multiline_responses) return;
3018
3019 if (codelen > 4)
3020 {
3021 esc = code + 4;
3022 esclen = codelen - 4;
3023 }
3024
3025 /* If this is the first output for a (non-batch) RCPT command, see if all RCPTs
3026 have had the same. Note: this code is also present in smtp_printf(). It would
3027 be tidier to have it only in one place, but when it was added, it was easier to
3028 do it that way, so as not to have to mess with the code for the RCPT command,
3029 which sometimes uses smtp_printf() and sometimes smtp_respond(). */
3030
3031 if (rcpt_in_progress)
3032 {
3033 if (rcpt_smtp_response == NULL)
3034 rcpt_smtp_response = string_copy(msg);
3035 else if (rcpt_smtp_response_same &&
3036 Ustrcmp(rcpt_smtp_response, msg) != 0)
3037 rcpt_smtp_response_same = FALSE;
3038 rcpt_in_progress = FALSE;
3039 }
3040
3041 /* Now output the message, splitting it up into multiple lines if necessary.
3042 We only handle pipelining these responses as far as nonfinal/final groups,
3043 not the whole MAIL/RCPT/DATA response set. */
3044
3045 for (;;)
3046 {
3047 uschar *nl = Ustrchr(msg, '\n');
3048 if (nl == NULL)
3049 {
3050 smtp_printf("%.3s%c%.*s%s\r\n", !final, code, final ? ' ':'-', esclen, esc, msg);
3051 return;
3052 }
3053 else if (nl[1] == 0 || no_multiline_responses)
3054 {
3055 smtp_printf("%.3s%c%.*s%.*s\r\n", !final, code, final ? ' ':'-', esclen, esc,
3056 (int)(nl - msg), msg);
3057 return;
3058 }
3059 else
3060 {
3061 smtp_printf("%.3s-%.*s%.*s\r\n", TRUE, code, esclen, esc, (int)(nl - msg), msg);
3062 msg = nl + 1;
3063 while (isspace(*msg)) msg++;
3064 }
3065 }
3066 }
3067
3068
3069
3070
3071 /*************************************************
3072 * Parse user SMTP message *
3073 *************************************************/
3074
3075 /* This function allows for user messages overriding the response code details
3076 by providing a suitable response code string at the start of the message
3077 user_msg. Check the message for starting with a response code and optionally an
3078 extended status code. If found, check that the first digit is valid, and if so,
3079 change the code pointer and length to use the replacement. An invalid code
3080 causes a panic log; in this case, if the log messages is the same as the user
3081 message, we must also adjust the value of the log message to show the code that
3082 is actually going to be used (the original one).
3083
3084 This function is global because it is called from receive.c as well as within
3085 this module.
3086
3087 Note that the code length returned includes the terminating whitespace
3088 character, which is always included in the regex match.
3089
3090 Arguments:
3091 code SMTP code, may involve extended status codes
3092 codelen length of smtp code; if > 4 there's an ESC
3093 msg message text
3094 log_msg optional log message, to be adjusted with the new SMTP code
3095 check_valid if true, verify the response code
3096
3097 Returns: nothing
3098 */
3099
3100 void
3101 smtp_message_code(uschar **code, int *codelen, uschar **msg, uschar **log_msg,
3102 BOOL check_valid)
3103 {
3104 int n;
3105 int ovector[3];
3106
3107 if (!msg || !*msg) return;
3108
3109 if ((n = pcre_exec(regex_smtp_code, NULL, CS *msg, Ustrlen(*msg), 0,
3110 PCRE_EOPT, ovector, sizeof(ovector)/sizeof(int))) < 0) return;
3111
3112 if (check_valid && (*msg)[0] != (*code)[0])
3113 {
3114 log_write(0, LOG_MAIN|LOG_PANIC, "configured error code starts with "
3115 "incorrect digit (expected %c) in \"%s\"", (*code)[0], *msg);
3116 if (log_msg != NULL && *log_msg == *msg)
3117 *log_msg = string_sprintf("%s %s", *code, *log_msg + ovector[1]);
3118 }
3119 else
3120 {
3121 *code = *msg;
3122 *codelen = ovector[1]; /* Includes final space */
3123 }
3124 *msg += ovector[1]; /* Chop the code off the message */
3125 return;
3126 }
3127
3128
3129
3130
3131 /*************************************************
3132 * Handle an ACL failure *
3133 *************************************************/
3134
3135 /* This function is called when acl_check() fails. As well as calls from within
3136 this module, it is called from receive.c for an ACL after DATA. It sorts out
3137 logging the incident, and sends the error response. A message containing
3138 newlines is turned into a multiline SMTP response, but for logging, only the
3139 first line is used.
3140
3141 There's a table of default permanent failure response codes to use in
3142 globals.c, along with the table of names. VFRY is special. Despite RFC1123 it
3143 defaults disabled in Exim. However, discussion in connection with RFC 821bis
3144 (aka RFC 2821) has concluded that the response should be 252 in the disabled
3145 state, because there are broken clients that try VRFY before RCPT. A 5xx
3146 response should be given only when the address is positively known to be
3147 undeliverable. Sigh. We return 252 if there is no VRFY ACL or it provides
3148 no explicit code, but if there is one we let it know best.
3149 Also, for ETRN, 458 is given on refusal, and for AUTH, 503.
3150
3151 From Exim 4.63, it is possible to override the response code details by
3152 providing a suitable response code string at the start of the message provided
3153 in user_msg. The code's first digit is checked for validity.
3154
3155 Arguments:
3156 where where the ACL was called from
3157 rc the failure code
3158 user_msg a message that can be included in an SMTP response
3159 log_msg a message for logging
3160
3161 Returns: 0 in most cases
3162 2 if the failure code was FAIL_DROP, in which case the
3163 SMTP connection should be dropped (this value fits with the
3164 "done" variable in smtp_setup_msg() below)
3165 */
3166
3167 int
3168 smtp_handle_acl_fail(int where, int rc, uschar *user_msg, uschar *log_msg)
3169 {
3170 BOOL drop = rc == FAIL_DROP;
3171 int codelen = 3;
3172 uschar *smtp_code;
3173 uschar *lognl;
3174 uschar *sender_info = US"";
3175 uschar *what =
3176 #ifdef WITH_CONTENT_SCAN
3177 where == ACL_WHERE_MIME ? US"during MIME ACL checks" :
3178 #endif
3179 where == ACL_WHERE_PREDATA ? US"DATA" :
3180 where == ACL_WHERE_DATA ? US"after DATA" :
3181 #ifndef DISABLE_PRDR
3182 where == ACL_WHERE_PRDR ? US"after DATA PRDR" :
3183 #endif
3184 smtp_cmd_data ?
3185 string_sprintf("%s %s", acl_wherenames[where], smtp_cmd_data) :
3186 string_sprintf("%s in \"connect\" ACL", acl_wherenames[where]);
3187
3188 if (drop) rc = FAIL;
3189
3190 /* Set the default SMTP code, and allow a user message to change it. */
3191
3192 smtp_code = rc == FAIL ? acl_wherecodes[where] : US"451";
3193 smtp_message_code(&smtp_code, &codelen, &user_msg, &log_msg,
3194 where != ACL_WHERE_VRFY);
3195
3196 /* We used to have sender_address here; however, there was a bug that was not
3197 updating sender_address after a rewrite during a verify. When this bug was
3198 fixed, sender_address at this point became the rewritten address. I'm not sure
3199 this is what should be logged, so I've changed to logging the unrewritten
3200 address to retain backward compatibility. */
3201
3202 #ifndef WITH_CONTENT_SCAN
3203 if (where == ACL_WHERE_RCPT || where == ACL_WHERE_DATA)
3204 #else
3205 if (where == ACL_WHERE_RCPT || where == ACL_WHERE_DATA || where == ACL_WHERE_MIME)
3206 #endif
3207 {
3208 sender_info = string_sprintf("F=<%s>%s%s%s%s ",
3209 sender_address_unrewritten ? sender_address_unrewritten : sender_address,
3210 sender_host_authenticated ? US" A=" : US"",
3211 sender_host_authenticated ? sender_host_authenticated : US"",
3212 sender_host_authenticated && authenticated_id ? US":" : US"",
3213 sender_host_authenticated && authenticated_id ? authenticated_id : US""
3214 );
3215 }
3216
3217 /* If there's been a sender verification failure with a specific message, and
3218 we have not sent a response about it yet, do so now, as a preliminary line for
3219 failures, but not defers. However, always log it for defer, and log it for fail
3220 unless the sender_verify_fail log selector has been turned off. */
3221
3222 if (sender_verified_failed &&
3223 !testflag(sender_verified_failed, af_sverify_told))
3224 {
3225 BOOL save_rcpt_in_progress = rcpt_in_progress;
3226 rcpt_in_progress = FALSE; /* So as not to treat these as the error */
3227
3228 setflag(sender_verified_failed, af_sverify_told);
3229
3230 if (rc != FAIL || LOGGING(sender_verify_fail))
3231 log_write(0, LOG_MAIN|LOG_REJECT, "%s sender verify %s for <%s>%s",
3232 host_and_ident(TRUE),
3233 ((sender_verified_failed->special_action & 255) == DEFER)? "defer":"fail",
3234 sender_verified_failed->address,
3235 (sender_verified_failed->message == NULL)? US"" :
3236 string_sprintf(": %s", sender_verified_failed->message));
3237
3238 if (rc == FAIL && sender_verified_failed->user_message)
3239 smtp_respond(smtp_code, codelen, FALSE, string_sprintf(
3240 testflag(sender_verified_failed, af_verify_pmfail)?
3241 "Postmaster verification failed while checking <%s>\n%s\n"
3242 "Several RFCs state that you are required to have a postmaster\n"
3243 "mailbox for each mail domain. This host does not accept mail\n"
3244 "from domains whose servers reject the postmaster address."
3245 :
3246 testflag(sender_verified_failed, af_verify_nsfail)?
3247 "Callback setup failed while verifying <%s>\n%s\n"
3248 "The initial connection, or a HELO or MAIL FROM:<> command was\n"
3249 "rejected. Refusing MAIL FROM:<> does not help fight spam, disregards\n"
3250 "RFC requirements, and stops you from receiving standard bounce\n"
3251 "messages. This host does not accept mail from domains whose servers\n"
3252 "refuse bounces."
3253 :
3254 "Verification failed for <%s>\n%s",
3255 sender_verified_failed->address,
3256 sender_verified_failed->user_message));
3257
3258 rcpt_in_progress = save_rcpt_in_progress;
3259 }
3260
3261 /* Sort out text for logging */
3262
3263 log_msg = log_msg ? string_sprintf(": %s", log_msg) : US"";
3264 if ((lognl = Ustrchr(log_msg, '\n'))) *lognl = 0;
3265
3266 /* Send permanent failure response to the command, but the code used isn't
3267 always a 5xx one - see comments at the start of this function. If the original
3268 rc was FAIL_DROP we drop the connection and yield 2. */
3269
3270 if (rc == FAIL)
3271 smtp_respond(smtp_code, codelen, TRUE,
3272 user_msg ? user_msg : US"Administrative prohibition");
3273
3274 /* Send temporary failure response to the command. Don't give any details,
3275 unless acl_temp_details is set. This is TRUE for a callout defer, a "defer"
3276 verb, and for a header verify when smtp_return_error_details is set.
3277
3278 This conditional logic is all somewhat of a mess because of the odd
3279 interactions between temp_details and return_error_details. One day it should
3280 be re-implemented in a tidier fashion. */
3281
3282 else
3283 if (acl_temp_details && user_msg)
3284 {
3285 if ( smtp_return_error_details
3286 && sender_verified_failed
3287 && sender_verified_failed->message
3288 )
3289 smtp_respond(smtp_code, codelen, FALSE, sender_verified_failed->message);
3290
3291 smtp_respond(smtp_code, codelen, TRUE, user_msg);
3292 }
3293 else
3294 smtp_respond(smtp_code, codelen, TRUE,
3295 US"Temporary local problem - please try later");
3296
3297 /* Log the incident to the logs that are specified by log_reject_target
3298 (default main, reject). This can be empty to suppress logging of rejections. If
3299 the connection is not forcibly to be dropped, return 0. Otherwise, log why it
3300 is closing if required and return 2. */
3301
3302 if (log_reject_target != 0)
3303 {
3304 #ifdef SUPPORT_TLS
3305 gstring * g = s_tlslog(NULL);
3306 uschar * tls = string_from_gstring(g);
3307 if (!tls) tls = US"";
3308 #else
3309 uschar * tls = US"";
3310 #endif
3311 log_write(where == ACL_WHERE_CONNECT ? L_connection_reject : 0,
3312 log_reject_target, "%s%s%s %s%srejected %s%s",
3313 LOGGING(dnssec) && sender_host_dnssec ? US" DS" : US"",
3314 host_and_ident(TRUE),
3315 tls,
3316 sender_info,
3317 rc == FAIL ? US"" : US"temporarily ",
3318 what, log_msg);
3319 }
3320
3321 if (!drop) return 0;
3322
3323 log_write(L_smtp_connection, LOG_MAIN, "%s closed by DROP in ACL",
3324 smtp_get_connection_info());
3325
3326 /* Run the not-quit ACL, but without any custom messages. This should not be a
3327 problem, because we get here only if some other ACL has issued "drop", and
3328 in that case, *its* custom messages will have been used above. */
3329
3330 smtp_notquit_exit(US"acl-drop", NULL, NULL);
3331 return 2;
3332 }
3333
3334
3335
3336
3337 /*************************************************
3338 * Handle SMTP exit when QUIT is not given *
3339 *************************************************/
3340
3341 /* This function provides a logging/statistics hook for when an SMTP connection
3342 is dropped on the floor or the other end goes away. It's a global function
3343 because it's called from receive.c as well as this module. As well as running
3344 the NOTQUIT ACL, if there is one, this function also outputs a final SMTP
3345 response, either with a custom message from the ACL, or using a default. There
3346 is one case, however, when no message is output - after "drop". In that case,
3347 the ACL that obeyed "drop" has already supplied the custom message, and NULL is
3348 passed to this function.
3349
3350 In case things go wrong while processing this function, causing an error that
3351 may re-enter this function, there is a recursion check.
3352
3353 Arguments:
3354 reason What $smtp_notquit_reason will be set to in the ACL;
3355 if NULL, the ACL is not run
3356 code The error code to return as part of the response
3357 defaultrespond The default message if there's no user_msg
3358
3359 Returns: Nothing
3360 */
3361
3362 void
3363 smtp_notquit_exit(uschar *reason, uschar *code, uschar *defaultrespond, ...)
3364 {
3365 int rc;
3366 uschar *user_msg = NULL;
3367 uschar *log_msg = NULL;
3368
3369 /* Check for recursive acll */
3370
3371 if (smtp_exit_function_called)
3372 {
3373 log_write(0, LOG_PANIC, "smtp_notquit_exit() called more than once (%s)",
3374 reason);
3375 return;
3376 }
3377 smtp_exit_function_called = TRUE;
3378
3379 /* Call the not-QUIT ACL, if there is one, unless no reason is given. */
3380
3381 if (acl_smtp_notquit && reason)
3382 {
3383 smtp_notquit_reason = reason;
3384 if ((rc = acl_check(ACL_WHERE_NOTQUIT, NULL, acl_smtp_notquit, &user_msg,
3385 &log_msg)) == ERROR)
3386 log_write(0, LOG_MAIN|LOG_PANIC, "ACL for not-QUIT returned ERROR: %s",
3387 log_msg);
3388 }
3389
3390 /* Write an SMTP response if we are expected to give one. As the default
3391 responses are all internal, they should always fit in the buffer, but code a
3392 warning, just in case. Note that string_vformat() still leaves a complete
3393 string, even if it is incomplete. */
3394
3395 if (code && defaultrespond)
3396 {
3397 if (user_msg)
3398 smtp_respond(code, 3, TRUE, user_msg);
3399 else
3400 {
3401 uschar buffer[128];
3402 va_list ap;
3403 va_start(ap, defaultrespond);
3404 if (!string_vformat(buffer, sizeof(buffer), CS defaultrespond, ap))
3405 log_write(0, LOG_MAIN|LOG_PANIC, "string too large in smtp_notquit_exit()");
3406 smtp_printf("%s %s\r\n", FALSE, code, buffer);
3407 va_end(ap);
3408 }
3409 mac_smtp_fflush();
3410 }
3411 }
3412
3413
3414
3415
3416 /*************************************************
3417 * Verify HELO argument *
3418 *************************************************/
3419
3420 /* This function is called if helo_verify_hosts or helo_try_verify_hosts is
3421 matched. It is also called from ACL processing if verify = helo is used and
3422 verification was not previously tried (i.e. helo_try_verify_hosts was not
3423 matched). The result of its processing is to set helo_verified and
3424 helo_verify_failed. These variables should both be FALSE for this function to
3425 be called.
3426
3427 Note that EHLO/HELO is legitimately allowed to quote an address literal. Allow
3428 for IPv6 ::ffff: literals.
3429
3430 Argument: none
3431 Returns: TRUE if testing was completed;
3432 FALSE on a temporary failure
3433 */
3434
3435 BOOL
3436 smtp_verify_helo(void)
3437 {
3438 BOOL yield = TRUE;
3439
3440 HDEBUG(D_receive) debug_printf("verifying EHLO/HELO argument \"%s\"\n",
3441 sender_helo_name);
3442
3443 if (sender_helo_name == NULL)
3444 {
3445 HDEBUG(D_receive) debug_printf("no EHLO/HELO command was issued\n");
3446 }
3447
3448 /* Deal with the case of -bs without an IP address */
3449
3450 else if (sender_host_address == NULL)
3451 {
3452 HDEBUG(D_receive) debug_printf("no client IP address: assume success\n");
3453 helo_verified = TRUE;
3454 }
3455
3456 /* Deal with the more common case when there is a sending IP address */
3457
3458 else if (sender_helo_name[0] == '[')
3459 {
3460 helo_verified = Ustrncmp(sender_helo_name+1, sender_host_address,
3461 Ustrlen(sender_host_address)) == 0;
3462
3463 #if HAVE_IPV6
3464 if (!helo_verified)
3465 {
3466 if (strncmpic(sender_host_address, US"::ffff:", 7) == 0)
3467 helo_verified = Ustrncmp(sender_helo_name + 1,
3468 sender_host_address + 7, Ustrlen(sender_host_address) - 7) == 0;
3469 }
3470 #endif
3471
3472 HDEBUG(D_receive)
3473 { if (helo_verified) debug_printf("matched host address\n"); }
3474 }
3475
3476 /* Do a reverse lookup if one hasn't already given a positive or negative
3477 response. If that fails, or the name doesn't match, try checking with a forward
3478 lookup. */
3479
3480 else
3481 {
3482 if (sender_host_name == NULL && !host_lookup_failed)
3483 yield = host_name_lookup() != DEFER;
3484
3485 /* If a host name is known, check it and all its aliases. */
3486
3487 if (sender_host_name)
3488 if ((helo_verified = strcmpic(sender_host_name, sender_helo_name) == 0))
3489 {
3490 sender_helo_dnssec = sender_host_dnssec;
3491 HDEBUG(D_receive) debug_printf("matched host name\n");
3492 }
3493 else
3494 {
3495 uschar **aliases = sender_host_aliases;
3496 while (*aliases)
3497 if ((helo_verified = strcmpic(*aliases++, sender_helo_name) == 0))
3498 {
3499 sender_helo_dnssec = sender_host_dnssec;
3500 break;
3501 }
3502
3503 HDEBUG(D_receive) if (helo_verified)
3504 debug_printf("matched alias %s\n", *(--aliases));
3505 }
3506
3507 /* Final attempt: try a forward lookup of the helo name */
3508
3509 if (!helo_verified)
3510 {
3511 int rc;
3512 host_item h;
3513 dnssec_domains d;
3514 host_item *hh;
3515
3516 h.name = sender_helo_name;
3517 h.address = NULL;
3518 h.mx = MX_NONE;
3519 h.next = NULL;
3520 d.request = US"*";
3521 d.require = US"";
3522
3523 HDEBUG(D_receive) debug_printf("getting IP address for %s\n",
3524 sender_helo_name);
3525 rc = host_find_bydns(&h, NULL, HOST_FIND_BY_A | HOST_FIND_BY_AAAA,
3526 NULL, NULL, NULL, &d, NULL, NULL);
3527 if (rc == HOST_FOUND || rc == HOST_FOUND_LOCAL)
3528 for (hh = &h; hh; hh = hh->next)
3529 if (Ustrcmp(hh->address, sender_host_address) == 0)
3530 {
3531 helo_verified = TRUE;
3532 if (h.dnssec == DS_YES) sender_helo_dnssec = TRUE;
3533 HDEBUG(D_receive)
3534 {
3535 debug_printf("IP address for %s matches calling address\n"
3536 "Forward DNS security status: %sverified\n",
3537 sender_helo_name, sender_helo_dnssec ? "" : "un");
3538 }
3539 break;
3540 }
3541 }
3542 }
3543
3544 if (!helo_verified) helo_verify_failed = TRUE; /* We've tried ... */
3545 return yield;
3546 }
3547
3548
3549
3550
3551 /*************************************************
3552 * Send user response message *
3553 *************************************************/
3554
3555 /* This function is passed a default response code and a user message. It calls
3556 smtp_message_code() to check and possibly modify the response code, and then
3557 calls smtp_respond() to transmit the response. I put this into a function
3558 just to avoid a lot of repetition.
3559
3560 Arguments:
3561 code the response code
3562 user_msg the user message
3563
3564 Returns: nothing
3565 */
3566
3567 static void
3568 smtp_user_msg(uschar *code, uschar *user_msg)
3569 {
3570 int len = 3;
3571 smtp_message_code(&code, &len, &user_msg, NULL, TRUE);
3572 smtp_respond(code, len, TRUE, user_msg);
3573 }
3574
3575
3576
3577 static int
3578 smtp_in_auth(auth_instance *au, uschar ** s, uschar ** ss)
3579 {
3580 const uschar *set_id = NULL;
3581 int rc, i;
3582
3583 /* Run the checking code, passing the remainder of the command line as
3584 data. Initials the $auth<n> variables as empty. Initialize $0 empty and set
3585 it as the only set numerical variable. The authenticator may set $auth<n>
3586 and also set other numeric variables. The $auth<n> variables are preferred
3587 nowadays; the numerical variables remain for backwards compatibility.
3588
3589 Afterwards, have a go at expanding the set_id string, even if
3590 authentication failed - for bad passwords it can be useful to log the
3591 userid. On success, require set_id to expand and exist, and put it in
3592 authenticated_id. Save this in permanent store, as the working store gets
3593 reset at HELO, RSET, etc. */
3594
3595 for (i = 0; i < AUTH_VARS; i++) auth_vars[i] = NULL;
3596 expand_nmax = 0;
3597 expand_nlength[0] = 0; /* $0 contains nothing */
3598
3599 rc = (au->info->servercode)(au, smtp_cmd_data);
3600 if (au->set_id) set_id = expand_string(au->set_id);
3601 expand_nmax = -1; /* Reset numeric variables */
3602 for (i = 0; i < AUTH_VARS; i++) auth_vars[i] = NULL; /* Reset $auth<n> */
3603
3604 /* The value of authenticated_id is stored in the spool file and printed in
3605 log lines. It must not contain binary zeros or newline characters. In
3606 normal use, it never will, but when playing around or testing, this error
3607 can (did) happen. To guard against this, ensure that the id contains only
3608 printing characters. */
3609
3610 if (set_id) set_id = string_printing(set_id);
3611
3612 /* For the non-OK cases, set up additional logging data if set_id
3613 is not empty. */
3614
3615 if (rc != OK)
3616 set_id = set_id && *set_id
3617 ? string_sprintf(" (set_id=%s)", set_id) : US"";
3618
3619 /* Switch on the result */
3620
3621 switch(rc)
3622 {
3623 case OK:
3624 if (!au->set_id || set_id) /* Complete success */
3625 {
3626 if (set_id) authenticated_id = string_copy_malloc(set_id);
3627 sender_host_authenticated = au->name;
3628 sender_host_auth_pubname = au->public_name;
3629 authentication_failed = FALSE;
3630 authenticated_fail_id = NULL; /* Impossible to already be set? */
3631
3632 received_protocol =
3633 (sender_host_address ? protocols : protocols_local)
3634 [pextend + pauthed + (tls_in.active >= 0 ? pcrpted:0)];
3635 *s = *ss = US"235 Authentication succeeded";
3636 authenticated_by = au;
3637 break;
3638 }
3639
3640 /* Authentication succeeded, but we failed to expand the set_id string.
3641 Treat this as a temporary error. */
3642
3643 auth_defer_msg = expand_string_message;
3644 /* Fall through */
3645
3646 case DEFER:
3647 if (set_id) authenticated_fail_id = string_copy_malloc(set_id);
3648 *s = string_sprintf("435 Unable to authenticate at present%s",
3649 auth_defer_user_msg);
3650 *ss = string_sprintf("435 Unable to authenticate at present%s: %s",
3651 set_id, auth_defer_msg);
3652 break;
3653
3654 case BAD64:
3655 *s = *ss = US"501 Invalid base64 data";
3656 break;
3657
3658 case CANCELLED:
3659 *s = *ss = US"501 Authentication cancelled";
3660 break;
3661
3662 case UNEXPECTED:
3663 *s = *ss = US"553 Initial data not expected";
3664 break;
3665
3666 case FAIL:
3667 if (set_id) authenticated_fail_id = string_copy_malloc(set_id);
3668 *s = US"535 Incorrect authentication data";
3669 *ss = string_sprintf("535 Incorrect authentication data%s", set_id);
3670 break;
3671
3672 default:
3673 if (set_id) authenticated_fail_id = string_copy_malloc(set_id);
3674 *s = US"435 Internal error";
3675 *ss = string_sprintf("435 Internal error%s: return %d from authentication "
3676 "check", set_id, rc);
3677 break;
3678 }
3679
3680 return rc;
3681 }
3682
3683
3684
3685
3686
3687 static int
3688 qualify_recipient(uschar ** recipient, uschar * smtp_cmd_data, uschar * tag)
3689 {
3690 int rd;
3691 if (allow_unqualified_recipient || strcmpic(*recipient, US"postmaster") == 0)
3692 {
3693 DEBUG(D_receive) debug_printf("unqualified address %s accepted\n",
3694 *recipient);
3695 rd = Ustrlen(recipient) + 1;
3696 *recipient = rewrite_address_qualify(*recipient, TRUE);
3697 return rd;
3698 }
3699 smtp_printf("501 %s: recipient address must contain a domain\r\n", FALSE,
3700 smtp_cmd_data);
3701 log_write(L_smtp_syntax_error,
3702 LOG_MAIN|LOG_REJECT, "unqualified %s rejected: <%s> %s%s",
3703 tag, *recipient, host_and_ident(TRUE), host_lookup_msg);
3704 return 0;
3705 }
3706
3707
3708
3709
3710 static void
3711 smtp_quit_handler(uschar ** user_msgp, uschar ** log_msgp)
3712 {
3713 HAD(SCH_QUIT);
3714 incomplete_transaction_log(US"QUIT");
3715 if (acl_smtp_quit)
3716 {
3717 int rc = acl_check(ACL_WHERE_QUIT, NULL, acl_smtp_quit, user_msgp, log_msgp);
3718 if (rc == ERROR)
3719 log_write(0, LOG_MAIN|LOG_PANIC, "ACL for QUIT returned ERROR: %s",
3720 *log_msgp);
3721 }
3722 if (*user_msgp)
3723 smtp_respond(US"221", 3, TRUE, *user_msgp);
3724 else
3725 smtp_printf("221 %s closing connection\r\n", FALSE, smtp_active_hostname);
3726
3727 #ifdef SUPPORT_TLS
3728 tls_close(TRUE, TLS_SHUTDOWN_NOWAIT);
3729 #endif
3730
3731 log_write(L_smtp_connection, LOG_MAIN, "%s closed by QUIT",
3732 smtp_get_connection_info());
3733 }
3734
3735
3736 static void
3737 smtp_rset_handler(void)
3738 {
3739 HAD(SCH_RSET);
3740 incomplete_transaction_log(US"RSET");
3741 smtp_printf("250 Reset OK\r\n", FALSE);
3742 cmd_list[CMD_LIST_RSET].is_mail_cmd = FALSE;
3743 }
3744
3745
3746
3747 /*************************************************
3748 * Initialize for SMTP incoming message *
3749 *************************************************/
3750
3751 /* This function conducts the initial dialogue at the start of an incoming SMTP
3752 message, and builds a list of recipients. However, if the incoming message
3753 is part of a batch (-bS option) a separate function is called since it would
3754 be messy having tests splattered about all over this function. This function
3755 therefore handles the case where interaction is occurring. The input and output
3756 files are set up in smtp_in and smtp_out.
3757
3758 The global recipients_list is set to point to a vector of recipient_item
3759 blocks, whose number is given by recipients_count. This is extended by the
3760 receive_add_recipient() function. The global variable sender_address is set to
3761 the sender's address. The yield is +1 if a message has been successfully
3762 started, 0 if a QUIT command was encountered or the connection was refused from
3763 the particular host, or -1 if the connection was lost.
3764
3765 Argument: none
3766
3767 Returns: > 0 message successfully started (reached DATA)
3768 = 0 QUIT read or end of file reached or call refused
3769 < 0 lost connection
3770 */
3771
3772 int
3773 smtp_setup_msg(void)
3774 {
3775 int done = 0;
3776 BOOL toomany = FALSE;
3777 BOOL discarded = FALSE;
3778 BOOL last_was_rej_mail = FALSE;
3779 BOOL last_was_rcpt = FALSE;
3780 void *reset_point = store_get(0);
3781
3782 DEBUG(D_receive) debug_printf("smtp_setup_msg entered\n");
3783
3784 /* Reset for start of new message. We allow one RSET not to be counted as a
3785 nonmail command, for those MTAs that insist on sending it between every
3786 message. Ditto for EHLO/HELO and for STARTTLS, to allow for going in and out of
3787 TLS between messages (an Exim client may do this if it has messages queued up
3788 for the host). Note: we do NOT reset AUTH at this point. */
3789
3790 smtp_reset(reset_point);
3791 message_ended = END_NOTSTARTED;
3792
3793 chunking_state = chunking_offered ? CHUNKING_OFFERED : CHUNKING_NOT_OFFERED;
3794
3795 cmd_list[CMD_LIST_RSET].is_mail_cmd = TRUE;
3796 cmd_list[CMD_LIST_HELO].is_mail_cmd = TRUE;
3797 cmd_list[CMD_LIST_EHLO].is_mail_cmd = TRUE;
3798 #ifdef SUPPORT_TLS
3799 cmd_list[CMD_LIST_STARTTLS].is_mail_cmd = TRUE;
3800 #endif
3801
3802 /* Set the local signal handler for SIGTERM - it tries to end off tidily */
3803
3804 os_non_restarting_signal(SIGTERM, command_sigterm_handler);
3805
3806 /* Batched SMTP is handled in a different function. */
3807
3808 if (smtp_batched_input) return smtp_setup_batch_msg();
3809
3810 /* Deal with SMTP commands. This loop is exited by setting done to a POSITIVE
3811 value. The values are 2 larger than the required yield of the function. */
3812
3813 while (done <= 0)
3814 {
3815 const uschar **argv;
3816 uschar *etrn_command;
3817 uschar *etrn_serialize_key;
3818 uschar *errmess;
3819 uschar *log_msg, *smtp_code;
3820 uschar *user_msg = NULL;
3821 uschar *recipient = NULL;
3822 uschar *hello = NULL;
3823 uschar *s, *ss;
3824 BOOL was_rej_mail = FALSE;
3825 BOOL was_rcpt = FALSE;
3826 void (*oldsignal)(int);
3827 pid_t pid;
3828 int start, end, sender_domain, recipient_domain;
3829 int rc;
3830 int c;
3831 auth_instance *au;
3832 uschar *orcpt = NULL;
3833 int flags;
3834 gstring * g;
3835
3836 #ifdef AUTH_TLS
3837 /* Check once per STARTTLS or SSL-on-connect for a TLS AUTH */
3838 if ( tls_in.active >= 0
3839 && tls_in.peercert
3840 && tls_in.certificate_verified
3841 && cmd_list[CMD_LIST_TLS_AUTH].is_mail_cmd
3842 )
3843 {
3844 cmd_list[CMD_LIST_TLS_AUTH].is_mail_cmd = FALSE;
3845
3846 for (au = auths; au; au = au->next)
3847 if (strcmpic(US"tls", au->driver_name) == 0)
3848 {
3849 if ( acl_smtp_auth
3850 && (rc = acl_check(ACL_WHERE_AUTH, NULL, acl_smtp_auth,
3851 &user_msg, &log_msg)) != OK
3852 )
3853 done = smtp_handle_acl_fail(ACL_WHERE_AUTH, rc, user_msg, log_msg);
3854 else
3855 {
3856 smtp_cmd_data = NULL;
3857
3858 if (smtp_in_auth(au, &s, &ss) == OK)
3859 { DEBUG(D_auth) debug_printf("tls auth succeeded\n"); }
3860 else
3861 { DEBUG(D_auth) debug_printf("tls auth not succeeded\n"); }
3862 }
3863 break;
3864 }
3865 }
3866 #endif
3867
3868 #ifdef TCP_QUICKACK
3869 if (smtp_in) /* Avoid pure-ACKs while in cmd pingpong phase */
3870 (void) setsockopt(fileno(smtp_in), IPPROTO_TCP, TCP_QUICKACK,
3871 US &off, sizeof(off));
3872 #endif
3873
3874 switch(smtp_read_command(TRUE, GETC_BUFFER_UNLIMITED))
3875 {
3876 /* The AUTH command is not permitted to occur inside a transaction, and may
3877 occur successfully only once per connection. Actually, that isn't quite
3878 true. When TLS is started, all previous information about a connection must
3879 be discarded, so a new AUTH is permitted at that time.
3880
3881 AUTH may only be used when it has been advertised. However, it seems that
3882 there are clients that send AUTH when it hasn't been advertised, some of
3883 them even doing this after HELO. And there are MTAs that accept this. Sigh.
3884 So there's a get-out that allows this to happen.
3885
3886 AUTH is initially labelled as a "nonmail command" so that one occurrence
3887 doesn't get counted. We change the label here so that multiple failing
3888 AUTHS will eventually hit the nonmail threshold. */
3889
3890 case AUTH_CMD:
3891 HAD(SCH_AUTH);
3892 authentication_failed = TRUE;
3893 cmd_list[CMD_LIST_AUTH].is_mail_cmd = FALSE;
3894
3895 if (!auth_advertised && !allow_auth_unadvertised)
3896 {
3897 done = synprot_error(L_smtp_protocol_error, 503, NULL,
3898 US"AUTH command used when not advertised");
3899 break;
3900 }
3901 if (sender_host_authenticated)
3902 {
3903 done = synprot_error(L_smtp_protocol_error, 503, NULL,
3904 US"already authenticated");
3905 break;
3906 }
3907 if (sender_address)
3908 {
3909 done = synprot_error(L_smtp_protocol_error, 503, NULL,
3910 US"not permitted in mail transaction");
3911 break;
3912 }
3913
3914 /* Check the ACL */
3915
3916 if ( acl_smtp_auth
3917 && (rc = acl_check(ACL_WHERE_AUTH, NULL, acl_smtp_auth,
3918 &user_msg, &log_msg)) != OK
3919 )
3920 {
3921 done = smtp_handle_acl_fail(ACL_WHERE_AUTH, rc, user_msg, log_msg);
3922 break;
3923 }
3924
3925 /* Find the name of the requested authentication mechanism. */
3926
3927 s = smtp_cmd_data;
3928 while ((c = *smtp_cmd_data) != 0 && !isspace(c))
3929 {
3930 if (!isalnum(c) && c != '-' && c != '_')
3931 {
3932 done = synprot_error(L_smtp_syntax_error, 501, NULL,
3933 US"invalid character in authentication mechanism name");
3934 goto COMMAND_LOOP;
3935 }
3936 smtp_cmd_data++;
3937 }
3938
3939 /* If not at the end of the line, we must be at white space. Terminate the
3940 name and move the pointer on to any data that may be present. */
3941
3942 if (*smtp_cmd_data != 0)
3943 {
3944 *smtp_cmd_data++ = 0;
3945 while (isspace(*smtp_cmd_data)) smtp_cmd_data++;
3946 }
3947
3948 /* Search for an authentication mechanism which is configured for use
3949 as a server and which has been advertised (unless, sigh, allow_auth_
3950 unadvertised is set). */
3951
3952 for (au = auths; au; au = au->next)
3953 if (strcmpic(s, au->public_name) == 0 && au->server &&
3954 (au->advertised || allow_auth_unadvertised))
3955 break;
3956
3957 if (au)
3958 {
3959 c = smtp_in_auth(au, &s, &ss);
3960
3961 smtp_printf("%s\r\n", FALSE, s);
3962 if (c != OK)
3963 log_write(0, LOG_MAIN|LOG_REJECT, "%s authenticator failed for %s: %s",
3964 au->name, host_and_ident(FALSE), ss);
3965 }
3966 else
3967 done = synprot_error(L_smtp_protocol_error, 504, NULL,
3968 string_sprintf("%s authentication mechanism not supported", s));
3969
3970 break; /* AUTH_CMD */
3971
3972 /* The HELO/EHLO commands are permitted to appear in the middle of a
3973 session as well as at the beginning. They have the effect of a reset in
3974 addition to their other functions. Their absence at the start cannot be
3975 taken to be an error.
3976
3977 RFC 2821 says:
3978
3979 If the EHLO command is not acceptable to the SMTP server, 501, 500,
3980 or 502 failure replies MUST be returned as appropriate. The SMTP
3981 server MUST stay in the same state after transmitting these replies
3982 that it was in before the EHLO was received.
3983
3984 Therefore, we do not do the reset until after checking the command for
3985 acceptability. This change was made for Exim release 4.11. Previously
3986 it did the reset first. */
3987
3988 case HELO_CMD:
3989 HAD(SCH_HELO);
3990 hello = US"HELO";
3991 esmtp = FALSE;
3992 goto HELO_EHLO;
3993
3994 case EHLO_CMD:
3995 HAD(SCH_EHLO);
3996 hello = US"EHLO";
3997 esmtp = TRUE;
3998
3999 HELO_EHLO: /* Common code for HELO and EHLO */
4000 cmd_list[CMD_LIST_HELO].is_mail_cmd = FALSE;
4001 cmd_list[CMD_LIST_EHLO].is_mail_cmd = FALSE;
4002
4003 /* Reject the HELO if its argument was invalid or non-existent. A
4004 successful check causes the argument to be saved in malloc store. */
4005
4006 if (!check_helo(smtp_cmd_data))
4007 {
4008 smtp_printf("501 Syntactically invalid %s argument(s)\r\n", FALSE, hello);
4009
4010 log_write(0, LOG_MAIN|LOG_REJECT, "rejected %s from %s: syntactically "
4011 "invalid argument(s): %s", hello, host_and_ident(FALSE),
4012 (*smtp_cmd_argument == 0)? US"(no argument given)" :
4013 string_printing(smtp_cmd_argument));
4014
4015 if (++synprot_error_count > smtp_max_synprot_errors)
4016 {
4017 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
4018 "syntax or protocol errors (last command was \"%s\")",
4019 host_and_ident(FALSE), string_printing(smtp_cmd_buffer));
4020 done = 1;
4021 }
4022
4023 break;
4024 }
4025
4026 /* If sender_host_unknown is true, we have got here via the -bs interface,
4027 not called from inetd. Otherwise, we are running an IP connection and the
4028 host address will be set. If the helo name is the primary name of this
4029 host and we haven't done a reverse lookup, force one now. If helo_required
4030 is set, ensure that the HELO name matches the actual host. If helo_verify
4031 is set, do the same check, but softly. */
4032
4033 if (!sender_host_unknown)
4034 {
4035 BOOL old_helo_verified = helo_verified;
4036 uschar *p = smtp_cmd_data;
4037
4038 while (*p != 0 && !isspace(*p)) { *p = tolower(*p); p++; }
4039 *p = 0;
4040
4041 /* Force a reverse lookup if HELO quoted something in helo_lookup_domains
4042 because otherwise the log can be confusing. */
4043
4044 if ( !sender_host_name
4045 && (deliver_domain = sender_helo_name, /* set $domain */
4046 match_isinlist(sender_helo_name, CUSS &helo_lookup_domains, 0,
4047 &domainlist_anchor, NULL, MCL_DOMAIN, TRUE, NULL)) == OK)
4048 (void)host_name_lookup();
4049
4050 /* Rebuild the fullhost info to include the HELO name (and the real name
4051 if it was looked up.) */
4052
4053 host_build_sender_fullhost(); /* Rebuild */
4054 set_process_info("handling%s incoming connection from %s",
4055 (tls_in.active >= 0)? " TLS" : "", host_and_ident(FALSE));
4056
4057 /* Verify if configured. This doesn't give much security, but it does
4058 make some people happy to be able to do it. If helo_required is set,
4059 (host matches helo_verify_hosts) failure forces rejection. If helo_verify
4060 is set (host matches helo_try_verify_hosts), it does not. This is perhaps
4061 now obsolescent, since the verification can now be requested selectively
4062 at ACL time. */
4063
4064 helo_verified = helo_verify_failed = sender_helo_dnssec = FALSE;
4065 if (helo_required || helo_verify)
4066 {
4067 BOOL tempfail = !smtp_verify_helo();
4068 if (!helo_verified)
4069 {
4070 if (helo_required)
4071 {
4072 smtp_printf("%d %s argument does not match calling host\r\n", FALSE,
4073 tempfail? 451 : 550, hello);
4074 log_write(0, LOG_MAIN|LOG_REJECT, "%srejected \"%s %s\" from %s",
4075 tempfail? "temporarily " : "",
4076 hello, sender_helo_name, host_and_ident(FALSE));
4077 helo_verified = old_helo_verified;
4078 break; /* End of HELO/EHLO processing */
4079 }
4080 HDEBUG(D_all) debug_printf("%s verification failed but host is in "
4081 "helo_try_verify_hosts\n", hello);
4082 }
4083 }
4084 }
4085
4086 #ifdef SUPPORT_SPF
4087 /* set up SPF context */
4088 spf_init(sender_helo_name, sender_host_address);
4089 #endif
4090
4091 /* Apply an ACL check if one is defined; afterwards, recheck
4092 synchronization in case the client started sending in a delay. */
4093
4094 if (acl_smtp_helo)
4095 if ((rc = acl_check(ACL_WHERE_HELO, NULL, acl_smtp_helo,
4096 &user_msg, &log_msg)) != OK)
4097 {
4098 done = smtp_handle_acl_fail(ACL_WHERE_HELO, rc, user_msg, log_msg);
4099 if (sender_helo_name)
4100 {
4101 store_free(sender_helo_name);
4102 sender_helo_name = NULL;
4103 }
4104 host_build_sender_fullhost(); /* Rebuild */
4105 break;
4106 }
4107 else if (!check_sync()) goto SYNC_FAILURE;
4108
4109 /* Generate an OK reply. The default string includes the ident if present,
4110 and also the IP address if present. Reflecting back the ident is intended
4111 as a deterrent to mail forgers. For maximum efficiency, and also because
4112 some broken systems expect each response to be in a single packet, arrange
4113 that the entire reply is sent in one write(). */
4114
4115 auth_advertised = FALSE;
4116 pipelining_advertised = FALSE;
4117 #ifdef SUPPORT_TLS
4118 tls_advertised = FALSE;
4119 #endif
4120 dsn_advertised = FALSE;