1 /*************************************************
2 * Exim - an Internet mail transport agent *
3 *************************************************/
5 /* Copyright (c) University of Cambridge 1995 - 2018 */
6 /* See the file NOTICE for conditions of use and distribution. */
8 /* Functions for handling an incoming SMTP call. */
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. */
19 #ifdef USE_TCP_WRAPPERS
22 #define EXIM_HAVE_IPV6
28 #define HAVE_IPV6 TRUE
31 int allow_severity = LOG_INFO;
32 int deny_severity = LOG_NOTICE;
33 uschar *tcp_wrappers_name;
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.
47 #define SMTP_CMD_BUFFER_SIZE 16384
49 /* Size of buffer for reading SMTP incoming packets */
51 #define IN_BUFFER_SIZE 8192
53 /* Structure for SMTP command list */
60 short int is_mail_cmd;
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
68 /* These commands are required to be synchronized, i.e. to be the last in a
69 block of commands when pipelining. */
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 */
77 /* This is a dummy to identify the non-sync commands when pipelining */
79 NON_SYNC_CMD_PIPELINING,
81 /* These commands need not be synchronized when pipelining */
83 MAIL_CMD, RCPT_CMD, RSET_CMD,
85 /* This is a dummy to identify the non-sync commands when not pipelining */
87 NON_SYNC_CMD_NON_PIPELINING,
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. */
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. */
108 /* I'm not sure about these, but I don't think they matter. */
113 PROXY_FAIL_IGNORE_CMD,
116 /* These are specials that don't correspond to actual commands */
118 EOF_CMD, OTHER_CMD, BADARG_CMD, BADCHAR_CMD, BADSYN_CMD,
119 TOO_MANY_NONMAIL_CMD };
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. */
126 smtp_connection_had[smtp_ch_index++] = n; \
127 if (smtp_ch_index >= SMTP_HBUFF_SIZE) smtp_ch_index = 0
130 /*************************************************
131 * Local static variables *
132 *************************************************/
135 BOOL auth_advertised :1;
137 BOOL tls_advertised :1;
138 # ifdef EXPERIMENTAL_REQUIRETLS
139 BOOL requiretls_advertised :1;
142 BOOL dsn_advertised :1;
144 BOOL helo_required :1;
147 BOOL helo_accept_junk :1;
148 BOOL rcpt_smtp_response_same :1;
149 BOOL rcpt_in_progress :1;
150 BOOL smtp_exit_function_called :1;
152 BOOL smtputf8_advertised :1;
155 .helo_required = FALSE,
156 .helo_verify = FALSE,
157 .smtp_exit_function_called = FALSE,
160 static auth_instance *authenticated_by;
161 static int count_nonmail;
162 static int nonmail_command_count;
163 static int synprot_error_count;
164 static int unknown_command_count;
165 static int sync_cmd_limit;
166 static int smtp_write_error = 0;
168 static uschar *rcpt_smtp_response;
169 static uschar *smtp_data_buffer;
170 static uschar *smtp_cmd_data;
172 /* We need to know the position of RSET, HELO, EHLO, AUTH, and STARTTLS. Their
173 final fields of all except AUTH are forced TRUE at the start of a new message
174 setup, to allow one of each between messages that is not counted as a nonmail
175 command. (In fact, only one of HELO/EHLO is not counted.) Also, we have to
176 allow a new EHLO after starting up TLS.
178 AUTH is "falsely" labelled as a mail command initially, so that it doesn't get
179 counted. However, the flag is changed when AUTH is received, so that multiple
180 failing AUTHs will eventually hit the limit. After a successful AUTH, another
181 AUTH is already forbidden. After a TLS session is started, AUTH's flag is again
182 forced TRUE, to allow for the re-authentication that can happen at that point.
184 QUIT is also "falsely" labelled as a mail command so that it doesn't up the
185 count of non-mail commands and possibly provoke an error.
187 tls_auth is a pseudo-command, never expected in input. It is activated
188 on TLS startup and looks for a tls authenticator. */
190 static smtp_cmd_list cmd_list[] = {
191 /* name len cmd has_arg is_mail_cmd */
193 { "rset", sizeof("rset")-1, RSET_CMD, FALSE, FALSE }, /* First */
194 { "helo", sizeof("helo")-1, HELO_CMD, TRUE, FALSE },
195 { "ehlo", sizeof("ehlo")-1, EHLO_CMD, TRUE, FALSE },
196 { "auth", sizeof("auth")-1, AUTH_CMD, TRUE, TRUE },
198 { "starttls", sizeof("starttls")-1, STARTTLS_CMD, FALSE, FALSE },
199 { "tls_auth", 0, TLS_AUTH_CMD, FALSE, FALSE },
202 /* If you change anything above here, also fix the definitions below. */
204 { "mail from:", sizeof("mail from:")-1, MAIL_CMD, TRUE, TRUE },
205 { "rcpt to:", sizeof("rcpt to:")-1, RCPT_CMD, TRUE, TRUE },
206 { "data", sizeof("data")-1, DATA_CMD, FALSE, TRUE },
207 { "bdat", sizeof("bdat")-1, BDAT_CMD, TRUE, TRUE },
208 { "quit", sizeof("quit")-1, QUIT_CMD, FALSE, TRUE },
209 { "noop", sizeof("noop")-1, NOOP_CMD, TRUE, FALSE },
210 { "etrn", sizeof("etrn")-1, ETRN_CMD, TRUE, FALSE },
211 { "vrfy", sizeof("vrfy")-1, VRFY_CMD, TRUE, FALSE },
212 { "expn", sizeof("expn")-1, EXPN_CMD, TRUE, FALSE },
213 { "help", sizeof("help")-1, HELP_CMD, TRUE, FALSE }
216 static smtp_cmd_list *cmd_list_end =
217 cmd_list + sizeof(cmd_list)/sizeof(smtp_cmd_list);
219 #define CMD_LIST_RSET 0
220 #define CMD_LIST_HELO 1
221 #define CMD_LIST_EHLO 2
222 #define CMD_LIST_AUTH 3
223 #define CMD_LIST_STARTTLS 4
224 #define CMD_LIST_TLS_AUTH 5
226 /* This list of names is used for performing the smtp_no_mail logging action.
227 It must be kept in step with the SCH_xxx enumerations. */
229 static uschar *smtp_names[] =
231 US"NONE", US"AUTH", US"DATA", US"BDAT", US"EHLO", US"ETRN", US"EXPN",
232 US"HELO", US"HELP", US"MAIL", US"NOOP", US"QUIT", US"RCPT", US"RSET",
233 US"STARTTLS", US"VRFY" };
235 static uschar *protocols_local[] = {
236 US"local-smtp", /* HELO */
237 US"local-smtps", /* The rare case EHLO->STARTTLS->HELO */
238 US"local-esmtp", /* EHLO */
239 US"local-esmtps", /* EHLO->STARTTLS->EHLO */
240 US"local-esmtpa", /* EHLO->AUTH */
241 US"local-esmtpsa" /* EHLO->STARTTLS->EHLO->AUTH */
243 static uschar *protocols[] = {
245 US"smtps", /* The rare case EHLO->STARTTLS->HELO */
246 US"esmtp", /* EHLO */
247 US"esmtps", /* EHLO->STARTTLS->EHLO */
248 US"esmtpa", /* EHLO->AUTH */
249 US"esmtpsa" /* EHLO->STARTTLS->EHLO->AUTH */
254 #define pcrpted 1 /* added to pextend or pnormal */
255 #define pauthed 2 /* added to pextend */
257 /* Sanity check and validate optional args to MAIL FROM: envelope */
260 ENV_MAIL_OPT_SIZE, ENV_MAIL_OPT_BODY, ENV_MAIL_OPT_AUTH,
264 ENV_MAIL_OPT_RET, ENV_MAIL_OPT_ENVID,
268 #ifdef EXPERIMENTAL_REQUIRETLS
273 uschar * name; /* option requested during MAIL cmd */
274 int value; /* enum type */
275 BOOL need_value; /* TRUE requires value (name=value pair format)
276 FALSE is a singleton */
278 static env_mail_type_t env_mail_type_list[] = {
279 { US"SIZE", ENV_MAIL_OPT_SIZE, TRUE },
280 { US"BODY", ENV_MAIL_OPT_BODY, TRUE },
281 { US"AUTH", ENV_MAIL_OPT_AUTH, TRUE },
283 { US"PRDR", ENV_MAIL_OPT_PRDR, FALSE },
285 { US"RET", ENV_MAIL_OPT_RET, TRUE },
286 { US"ENVID", ENV_MAIL_OPT_ENVID, TRUE },
288 { US"SMTPUTF8",ENV_MAIL_OPT_UTF8, FALSE }, /* rfc6531 */
290 #ifdef EXPERIMENTAL_REQUIRETLS
291 /* https://tools.ietf.org/html/draft-ietf-uta-smtp-require-tls-03 */
292 { US"REQUIRETLS",ENV_MAIL_OPT_REQTLS, FALSE },
294 /* keep this the last entry */
295 { US"NULL", ENV_MAIL_OPT_NULL, FALSE },
298 /* When reading SMTP from a remote host, we have to use our own versions of the
299 C input-reading functions, in order to be able to flush the SMTP output only
300 when about to read more data from the socket. This is the only way to get
301 optimal performance when the client is using pipelining. Flushing for every
302 command causes a separate packet and reply packet each time; saving all the
303 responses up (when pipelining) combines them into one packet and one response.
305 For simplicity, these functions are used for *all* SMTP input, not only when
306 receiving over a socket. However, after setting up a secure socket (SSL), input
307 is read via the OpenSSL library, and another set of functions is used instead
310 These functions are set in the receive_getc etc. variables and called with the
311 same interface as the C functions. However, since there can only ever be
312 one incoming SMTP call, we just use a single buffer and flags. There is no need
313 to implement a complicated private FILE-like structure.*/
315 static uschar *smtp_inbuffer;
316 static uschar *smtp_inptr;
317 static uschar *smtp_inend;
318 static int smtp_had_eof;
319 static int smtp_had_error;
322 /* forward declarations */
323 static int smtp_read_command(BOOL check_sync, unsigned buffer_lim);
324 static int synprot_error(int type, int code, uschar *data, uschar *errmess);
325 static void smtp_quit_handler(uschar **, uschar **);
326 static void smtp_rset_handler(void);
328 /*************************************************
329 * Recheck synchronization *
330 *************************************************/
332 /* Synchronization checks can never be perfect because a packet may be on its
333 way but not arrived when the check is done. Normally, the checks happen when
334 commands are read: Exim ensures that there is no more input in the input buffer.
335 In normal cases, the response to the command will be fast, and there is no
338 However, for some commands an ACL is run, and that can include delays. In those
339 cases, it is useful to do another check on the input just before sending the
340 response. This also applies at the start of a connection. This function does
341 that check by means of the select() function, as long as the facility is not
342 disabled or inappropriate. A failure of select() is ignored.
344 When there is unwanted input, we read it so that it appears in the log of the
348 Returns: TRUE if all is well; FALSE if there is input pending
352 wouldblock_reading(void)
356 struct timeval tzero;
359 if (tls_in.active.sock >= 0)
360 return !tls_could_read();
363 if (smtp_inptr < smtp_inend)
366 fd = fileno(smtp_in);
371 rc = select(fd + 1, (SELECT_ARG2_TYPE *)&fds, NULL, NULL, &tzero);
373 if (rc <= 0) return TRUE; /* Not ready to read */
374 rc = smtp_getc(GETC_BUFFER_UNLIMITED);
375 if (rc < 0) return TRUE; /* End of file or error */
384 if (!smtp_enforce_sync || !sender_host_address || f.sender_host_notsocket)
387 return wouldblock_reading();
391 /* If there's input waiting (and we're doing pipelineing) then we can pipeline
392 a reponse with the one following. */
395 pipeline_response(void)
397 if ( !smtp_enforce_sync || !sender_host_address
398 || f.sender_host_notsocket || !f.smtp_in_pipelining_advertised)
401 if (wouldblock_reading()) return FALSE;
402 f.smtp_in_pipelining_used = TRUE;
408 /*************************************************
409 * Log incomplete transactions *
410 *************************************************/
412 /* This function is called after a transaction has been aborted by RSET, QUIT,
413 connection drops or other errors. It logs the envelope information received
414 so far in order to preserve address verification attempts.
416 Argument: string to indicate what aborted the transaction
421 incomplete_transaction_log(uschar *what)
423 if (sender_address == NULL || /* No transaction in progress */
424 !LOGGING(smtp_incomplete_transaction))
427 /* Build list of recipients for logging */
429 if (recipients_count > 0)
432 raw_recipients = store_get(recipients_count * sizeof(uschar *));
433 for (i = 0; i < recipients_count; i++)
434 raw_recipients[i] = recipients_list[i].address;
435 raw_recipients_count = recipients_count;
438 log_write(L_smtp_incomplete_transaction, LOG_MAIN|LOG_SENDER|LOG_RECIPIENTS,
439 "%s incomplete transaction (%s)", host_and_ident(TRUE), what);
446 smtp_command_timeout_exit(void)
448 log_write(L_lost_incoming_connection,
449 LOG_MAIN, "SMTP command timeout on%s connection from %s",
450 tls_in.active.sock >= 0 ? " TLS" : "", host_and_ident(FALSE));
451 if (smtp_batched_input)
452 moan_smtp_batch(NULL, "421 SMTP command timeout"); /* Does not return */
453 smtp_notquit_exit(US"command-timeout", US"421",
454 US"%s: SMTP command timeout - closing connection",
455 smtp_active_hostname);
456 exim_exit(EXIT_FAILURE, US"receiving");
460 smtp_command_sigterm_exit(void)
462 log_write(0, LOG_MAIN, "%s closed after SIGTERM", smtp_get_connection_info());
463 if (smtp_batched_input)
464 moan_smtp_batch(NULL, "421 SIGTERM received"); /* Does not return */
465 smtp_notquit_exit(US"signal-exit", US"421",
466 US"%s: Service not available - closing connection", smtp_active_hostname);
467 exim_exit(EXIT_FAILURE, US"receiving");
471 smtp_data_timeout_exit(void)
473 log_write(L_lost_incoming_connection,
474 LOG_MAIN, "SMTP data timeout (message abandoned) on connection from %s F=<%s>",
475 sender_fullhost ? sender_fullhost : US"local process", sender_address);
476 receive_bomb_out(US"data-timeout", US"SMTP incoming data timeout");
477 /* Does not return */
481 smtp_data_sigint_exit(void)
483 log_write(0, LOG_MAIN, "%s closed after %s",
484 smtp_get_connection_info(), had_data_sigint == SIGTERM ? "SIGTERM":"SIGINT");
485 receive_bomb_out(US"signal-exit",
486 US"Service not available - SIGTERM or SIGINT received");
487 /* Does not return */
492 /* Refill the buffer, and notify DKIM verification code.
493 Return false for error or EOF.
497 smtp_refill(unsigned lim)
500 if (!smtp_out) return FALSE;
502 if (smtp_receive_timeout > 0) alarm(smtp_receive_timeout);
504 /* Limit amount read, so non-message data is not fed to DKIM.
505 Take care to not touch the safety NUL at the end of the buffer. */
507 rc = read(fileno(smtp_in), smtp_inbuffer, MIN(IN_BUFFER_SIZE-1, lim));
509 if (smtp_receive_timeout > 0) alarm(0);
512 /* Must put the error text in fixed store, because this might be during
513 header reading, where it releases unused store above the header. */
516 if (had_command_timeout) /* set by signal handler */
517 smtp_command_timeout_exit(); /* does not return */
518 if (had_command_sigterm)
519 smtp_command_sigterm_exit();
520 if (had_data_timeout)
521 smtp_data_timeout_exit();
523 smtp_data_sigint_exit();
525 smtp_had_error = save_errno;
526 smtp_read_error = string_copy_malloc(
527 string_sprintf(" (error: %s)", strerror(save_errno)));
534 dkim_exim_verify_feed(smtp_inbuffer, rc);
536 smtp_inend = smtp_inbuffer + rc;
537 smtp_inptr = smtp_inbuffer;
541 /*************************************************
542 * SMTP version of getc() *
543 *************************************************/
545 /* This gets the next byte from the SMTP input buffer. If the buffer is empty,
546 it flushes the output, and refills the buffer, with a timeout. The signal
547 handler is set appropriately by the calling function. This function is not used
548 after a connection has negotiated itself into an TLS/SSL state.
550 Arguments: lim Maximum amount to read/buffer
551 Returns: the next character or EOF
555 smtp_getc(unsigned lim)
557 if (smtp_inptr >= smtp_inend)
558 if (!smtp_refill(lim))
560 return *smtp_inptr++;
564 smtp_getbuf(unsigned * len)
569 if (smtp_inptr >= smtp_inend)
570 if (!smtp_refill(*len))
571 { *len = 0; return NULL; }
573 if ((size = smtp_inend - smtp_inptr) > *len) size = *len;
584 int n = smtp_inend - smtp_inptr;
586 dkim_exim_verify_feed(smtp_inptr, n);
591 /* Get a byte from the smtp input, in CHUNKING mode. Handle ack of the
592 previous BDAT chunk and getting new ones when we run out. Uses the
593 underlying smtp_getc or tls_getc both for that and for getting the
594 (buffered) data byte. EOD signals (an expected) no further data.
595 ERR signals a protocol error, and EOF a closed input stream.
597 Called from read_bdat_smtp() in receive.c for the message body, but also
598 by the headers read loop in receive_msg(); manipulates chunking_state
599 to handle the BDAT command/response.
600 Placed here due to the correlation with the above smtp_getc(), which it wraps,
601 and also by the need to do smtp command/response handling.
603 Arguments: lim (ignored)
604 Returns: the next character or ERR, EOD or EOF
608 bdat_getc(unsigned lim)
610 uschar * user_msg = NULL;
619 if (chunking_data_left > 0)
620 return lwr_receive_getc(chunking_data_left--);
622 receive_getc = lwr_receive_getc;
623 receive_getbuf = lwr_receive_getbuf;
624 receive_ungetc = lwr_receive_ungetc;
626 dkim_save = dkim_collect_input;
627 dkim_collect_input = 0;
630 /* Unless PIPELINING was offered, there should be no next command
631 until after we ack that chunk */
633 if (!f.smtp_in_pipelining_advertised && !check_sync())
635 unsigned n = smtp_inend - smtp_inptr;
638 incomplete_transaction_log(US"sync failure");
639 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP protocol synchronization error "
640 "(next input sent too soon: pipelining was not advertised): "
641 "rejected \"%s\" %s next input=\"%s\"%s",
642 smtp_cmd_buffer, host_and_ident(TRUE),
643 string_printing(string_copyn(smtp_inptr, n)),
644 smtp_inend - smtp_inptr > n ? "..." : "");
645 (void) synprot_error(L_smtp_protocol_error, 554, NULL,
646 US"SMTP synchronization error");
647 goto repeat_until_rset;
650 /* If not the last, ack the received chunk. The last response is delayed
651 until after the data ACL decides on it */
653 if (chunking_state == CHUNKING_LAST)
656 dkim_exim_verify_feed(NULL, 0); /* notify EOD */
661 smtp_printf("250 %u byte chunk received\r\n", FALSE, chunking_datasize);
662 chunking_state = CHUNKING_OFFERED;
663 DEBUG(D_receive) debug_printf("chunking state %d\n", (int)chunking_state);
665 /* Expect another BDAT cmd from input. RFC 3030 says nothing about
666 QUIT, RSET or NOOP but handling them seems obvious */
669 switch(smtp_read_command(TRUE, 1))
672 (void) synprot_error(L_smtp_protocol_error, 503, NULL,
673 US"only BDAT permissible after non-LAST BDAT");
676 switch(smtp_read_command(TRUE, 1))
678 case QUIT_CMD: smtp_quit_handler(&user_msg, &log_msg); /*FALLTHROUGH */
679 case EOF_CMD: return EOF;
680 case RSET_CMD: smtp_rset_handler(); return ERR;
681 default: if (synprot_error(L_smtp_protocol_error, 503, NULL,
682 US"only RSET accepted now") > 0)
684 goto repeat_until_rset;
688 smtp_quit_handler(&user_msg, &log_msg);
699 smtp_printf("250 OK\r\n", FALSE);
706 if (sscanf(CS smtp_cmd_data, "%u %n", &chunking_datasize, &n) < 1)
708 (void) synprot_error(L_smtp_protocol_error, 501, NULL,
709 US"missing size for BDAT command");
712 chunking_state = strcmpic(smtp_cmd_data+n, US"LAST") == 0
713 ? CHUNKING_LAST : CHUNKING_ACTIVE;
714 chunking_data_left = chunking_datasize;
715 DEBUG(D_receive) debug_printf("chunking state %d, %d bytes\n",
716 (int)chunking_state, chunking_data_left);
718 if (chunking_datasize == 0)
719 if (chunking_state == CHUNKING_LAST)
723 (void) synprot_error(L_smtp_protocol_error, 504, NULL,
724 US"zero size for BDAT command");
725 goto repeat_until_rset;
728 receive_getc = bdat_getc;
729 receive_getbuf = bdat_getbuf; /* r~getbuf is never actually used */
730 receive_ungetc = bdat_ungetc;
732 dkim_collect_input = dkim_save;
734 break; /* to top of main loop */
741 bdat_getbuf(unsigned * len)
745 if (chunking_data_left <= 0)
746 { *len = 0; return NULL; }
748 if (*len > chunking_data_left) *len = chunking_data_left;
749 buf = lwr_receive_getbuf(len); /* Either smtp_getbuf or tls_getbuf */
750 chunking_data_left -= *len;
755 bdat_flush_data(void)
757 while (chunking_data_left)
759 unsigned n = chunking_data_left;
760 if (!bdat_getbuf(&n)) break;
763 receive_getc = lwr_receive_getc;
764 receive_getbuf = lwr_receive_getbuf;
765 receive_ungetc = lwr_receive_ungetc;
767 if (chunking_state != CHUNKING_LAST)
769 chunking_state = CHUNKING_OFFERED;
770 DEBUG(D_receive) debug_printf("chunking state %d\n", (int)chunking_state);
777 /*************************************************
778 * SMTP version of ungetc() *
779 *************************************************/
781 /* Puts a character back in the input buffer. Only ever
787 Returns: the character
801 chunking_data_left++;
802 return lwr_receive_ungetc(ch);
807 /*************************************************
808 * SMTP version of feof() *
809 *************************************************/
811 /* Tests for a previous EOF
814 Returns: non-zero if the eof flag is set
826 /*************************************************
827 * SMTP version of ferror() *
828 *************************************************/
830 /* Tests for a previous read error, and returns with errno
831 restored to what it was when the error was detected.
834 Returns: non-zero if the error flag is set
840 errno = smtp_had_error;
841 return smtp_had_error;
846 /*************************************************
847 * Test for characters in the SMTP buffer *
848 *************************************************/
850 /* Used at the end of a message
859 return smtp_inptr < smtp_inend;
864 /*************************************************
865 * Write formatted string to SMTP channel *
866 *************************************************/
868 /* This is a separate function so that we don't have to repeat everything for
869 TLS support or debugging. It is global so that the daemon and the
870 authentication functions can use it. It does not return any error indication,
871 because major problems such as dropped connections won't show up till an output
872 flush for non-TLS connections. The smtp_fflush() function is available for
873 checking that: for convenience, TLS output errors are remembered here so that
874 they are also picked up later by smtp_fflush().
878 more further data expected
879 ... optional arguments
885 smtp_printf(const char *format, BOOL more, ...)
890 smtp_vprintf(format, more, ap);
894 /* This is split off so that verify.c:respond_printf() can, in effect, call
895 smtp_printf(), bearing in mind that in C a vararg function can't directly
896 call another vararg function, only a function which accepts a va_list. */
899 smtp_vprintf(const char *format, BOOL more, va_list ap)
903 yield = string_vformat(big_buffer, big_buffer_size, format, ap);
907 void *reset_point = store_get(0);
908 uschar *msg_copy, *cr, *end;
909 msg_copy = string_copy(big_buffer);
910 end = msg_copy + Ustrlen(msg_copy);
911 while ((cr = Ustrchr(msg_copy, '\r')) != NULL) /* lose CRs */
912 memmove(cr, cr + 1, (end--) - cr);
913 debug_printf("SMTP>> %s", msg_copy);
914 store_reset(reset_point);
919 log_write(0, LOG_MAIN|LOG_PANIC, "string too large in smtp_printf()");
920 smtp_closedown(US"Unexpected error");
921 exim_exit(EXIT_FAILURE, NULL);
924 /* If this is the first output for a (non-batch) RCPT command, see if all RCPTs
925 have had the same. Note: this code is also present in smtp_respond(). It would
926 be tidier to have it only in one place, but when it was added, it was easier to
927 do it that way, so as not to have to mess with the code for the RCPT command,
928 which sometimes uses smtp_printf() and sometimes smtp_respond(). */
930 if (fl.rcpt_in_progress)
932 if (rcpt_smtp_response == NULL)
933 rcpt_smtp_response = string_copy(big_buffer);
934 else if (fl.rcpt_smtp_response_same &&
935 Ustrcmp(rcpt_smtp_response, big_buffer) != 0)
936 fl.rcpt_smtp_response_same = FALSE;
937 fl.rcpt_in_progress = FALSE;
940 /* Now write the string */
943 if (tls_in.active.sock >= 0)
945 if (tls_write(NULL, big_buffer, Ustrlen(big_buffer), more) < 0)
946 smtp_write_error = -1;
951 if (fprintf(smtp_out, "%s", big_buffer) < 0) smtp_write_error = -1;
956 /*************************************************
957 * Flush SMTP out and check for error *
958 *************************************************/
960 /* This function isn't currently used within Exim (it detects errors when it
961 tries to read the next SMTP input), but is available for use in local_scan().
962 For non-TLS connections, it flushes the output and checks for errors. For
963 TLS-connections, it checks for a previously-detected TLS write error.
966 Returns: 0 for no error; -1 after an error
972 if (tls_in.active.sock < 0 && fflush(smtp_out) != 0) smtp_write_error = -1;
973 return smtp_write_error;
978 /*************************************************
979 * SMTP command read timeout *
980 *************************************************/
982 /* Signal handler for timing out incoming SMTP commands. This attempts to
985 Argument: signal number (SIGALRM)
990 command_timeout_handler(int sig)
992 had_command_timeout = sig;
997 /*************************************************
999 *************************************************/
1001 /* Signal handler for handling SIGTERM. Again, try to finish tidily.
1003 Argument: signal number (SIGTERM)
1008 command_sigterm_handler(int sig)
1010 had_command_sigterm = sig;
1016 #ifdef SUPPORT_PROXY
1017 /*************************************************
1018 * Restore socket timeout to previous value *
1019 *************************************************/
1020 /* If the previous value was successfully retrieved, restore
1021 it before returning control to the non-proxy routines
1023 Arguments: fd - File descriptor for input
1024 get_ok - Successfully retrieved previous values
1025 tvtmp - Time struct with previous values
1026 vslen - Length of time struct
1030 restore_socket_timeout(int fd, int get_ok, struct timeval * tvtmp, socklen_t vslen)
1033 (void) setsockopt(fd, SOL_SOCKET, SO_RCVTIMEO, CS tvtmp, vslen);
1036 /*************************************************
1037 * Check if host is required proxy host *
1038 *************************************************/
1039 /* The function determines if inbound host will be a regular smtp host
1040 or if it is configured that it must use Proxy Protocol. A local
1048 check_proxy_protocol_host()
1052 if ( sender_host_address
1053 && (rc = verify_check_this_host(CUSS &hosts_proxy, NULL, NULL,
1054 sender_host_address, NULL)) == OK)
1057 debug_printf("Detected proxy protocol configured host\n");
1058 proxy_session = TRUE;
1060 return proxy_session;
1064 /*************************************************
1065 * Read data until newline or end of buffer *
1066 *************************************************/
1067 /* While SMTP is server-speaks-first, TLS is client-speaks-first, so we can't
1068 read an entire buffer and assume there will be nothing past a proxy protocol
1069 header. Our approach normally is to use stdio, but again that relies upon
1070 "STARTTLS\r\n" and a server response before the client starts TLS handshake, or
1071 reading _nothing_ before client TLS handshake. So we don't want to use the
1072 usual buffering reads which may read enough to block TLS starting.
1074 So unfortunately we're down to "read one byte at a time, with a syscall each,
1075 and expect a little overhead", for all proxy-opened connections which are v1,
1076 just to handle the TLS-on-connect case. Since SSL functions wrap the
1077 underlying fd, we can't assume that we can feed them any already-read content.
1079 We need to know where to read to, the max capacity, and we'll read until we
1080 get a CR and one more character. Let the caller scream if it's CR+!LF.
1082 Return the amount read.
1086 swallow_until_crlf(int fd, uschar *base, int already, int capacity)
1088 uschar *to = base + already;
1094 /* For "PROXY UNKNOWN\r\n" we, at time of writing, expect to have read
1095 up through the \r; for the _normal_ case, we haven't yet seen the \r. */
1097 cr = memchr(base, '\r', already);
1100 if ((cr - base) < already - 1)
1102 /* \r and presumed \n already within what we have; probably not
1103 actually proxy protocol, but abort cleanly. */
1106 /* \r is last character read, just need one more. */
1110 while (capacity > 0)
1112 do { ret = recv(fd, to, 1, 0); } while (ret == -1 && errno == EINTR);
1124 /* reached end without having room for a final newline, abort */
1129 /*************************************************
1130 * Setup host for proxy protocol *
1131 *************************************************/
1132 /* The function configures the connection based on a header from the
1133 inbound host to use Proxy Protocol. The specification is very exact
1134 so exit with an error if do not find the exact required pieces. This
1135 includes an incorrect number of spaces separating args.
1138 Returns: Boolean success
1142 setup_proxy_protocol_host()
1154 struct { /* TCP/UDP over IPv4, len = 12 */
1160 struct { /* TCP/UDP over IPv6, len = 36 */
1161 uint8_t src_addr[16];
1162 uint8_t dst_addr[16];
1166 struct { /* AF_UNIX sockets, len = 216 */
1167 uschar src_addr[108];
1168 uschar dst_addr[108];
1174 /* Temp variables used in PPv2 address:port parsing */
1176 char tmpip[INET_ADDRSTRLEN];
1177 struct sockaddr_in tmpaddr;
1178 char tmpip6[INET6_ADDRSTRLEN];
1179 struct sockaddr_in6 tmpaddr6;
1181 /* We can't read "all data until end" because while SMTP is
1182 server-speaks-first, the TLS handshake is client-speaks-first, so for
1183 TLS-on-connect ports the proxy protocol header will usually be immediately
1184 followed by a TLS handshake, and with N TLS libraries, we can't reliably
1185 reinject data for reading by those. So instead we first read "enough to be
1186 safely read within the header, and figure out how much more to read".
1187 For v1 we will later read to the end-of-line, for v2 we will read based upon
1190 The v2 sig is 12 octets, and another 4 gets us the length, so we know how much
1191 data is needed total. For v1, where the line looks like:
1192 PROXY TCPn L3src L3dest SrcPort DestPort \r\n
1194 However, for v1 there's also `PROXY UNKNOWN\r\n` which is only 15 octets.
1195 We seem to support that. So, if we read 14 octets then we can tell if we're
1196 v2 or v1. If we're v1, we can continue reading as normal.
1198 If we're v2, we can't slurp up the entire header. We need the length in the
1199 15th & 16th octets, then to read everything after that.
1201 So to safely handle v1 and v2, with client-sent-first supported correctly,
1202 we have to do a minimum of 3 read calls, not 1. Eww.
1205 #define PROXY_INITIAL_READ 14
1206 #define PROXY_V2_HEADER_SIZE 16
1207 #if PROXY_INITIAL_READ > PROXY_V2_HEADER_SIZE
1208 # error Code bug in sizes of data to read for proxy usage
1213 int fd = fileno(smtp_in);
1214 const char v2sig[12] = "\x0D\x0A\x0D\x0A\x00\x0D\x0A\x51\x55\x49\x54\x0A";
1215 uschar * iptype; /* To display debug info */
1217 struct timeval tvtmp;
1218 socklen_t vslen = sizeof(struct timeval);
1221 /* Save current socket timeout values */
1222 get_ok = getsockopt(fd, SOL_SOCKET, SO_RCVTIMEO, CS &tvtmp, &vslen);
1224 /* Proxy Protocol host must send header within a short time
1225 (default 3 seconds) or it's considered invalid */
1226 tv.tv_sec = PROXY_NEGOTIATION_TIMEOUT_SEC;
1227 tv.tv_usec = PROXY_NEGOTIATION_TIMEOUT_USEC;
1228 if (setsockopt(fd, SOL_SOCKET, SO_RCVTIMEO, CS &tv, sizeof(tv)) < 0)
1233 /* The inbound host was declared to be a Proxy Protocol host, so
1234 don't do a PEEK into the data, actually slurp up enough to be
1235 "safe". Can't take it all because TLS-on-connect clients follow
1236 immediately with TLS handshake. */
1237 ret = recv(fd, &hdr, PROXY_INITIAL_READ, 0);
1239 while (ret == -1 && errno == EINTR);
1244 /* For v2, handle reading the length, and then the rest. */
1245 if ((ret == PROXY_INITIAL_READ) && (memcmp(&hdr.v2, v2sig, sizeof(v2sig)) == 0))
1250 /* First get the length fields. */
1253 retmore = recv(fd, (uschar*)&hdr + ret, PROXY_V2_HEADER_SIZE - PROXY_INITIAL_READ, 0);
1254 } while (retmore == -1 && errno == EINTR);
1259 ver = (hdr.v2.ver_cmd & 0xf0) >> 4;
1261 /* May 2014: haproxy combined the version and command into one byte to
1262 allow two full bytes for the length field in order to proxy SSL
1263 connections. SSL Proxy is not supported in this version of Exim, but
1264 must still separate values here. */
1268 DEBUG(D_receive) debug_printf("Invalid Proxy Protocol version: %d\n", ver);
1272 /* The v2 header will always be 16 bytes per the spec. */
1273 size = 16 + ntohs(hdr.v2.len);
1274 DEBUG(D_receive) debug_printf("Detected PROXYv2 header, size %d (limit %d)\n",
1275 size, (int)sizeof(hdr));
1277 /* We should now have 16 octets (PROXY_V2_HEADER_SIZE), and we know the total
1278 amount that we need. Double-check that the size is not unreasonable, then
1280 if (size > sizeof(hdr))
1282 DEBUG(D_receive) debug_printf("PROXYv2 header size unreasonably large; security attack?\n");
1290 retmore = recv(fd, (uschar*)&hdr + ret, size-ret, 0);
1291 } while (retmore == -1 && errno == EINTR);
1295 DEBUG(D_receive) debug_printf("PROXYv2: have %d/%d required octets\n", ret, size);
1296 } while (ret < size);
1298 } /* end scope for getting rest of data for v2 */
1300 /* At this point: if PROXYv2, we've read the exact size required for all data;
1301 if PROXYv1 then we've read "less than required for any valid line" and should
1304 if (ret >= 16 && memcmp(&hdr.v2, v2sig, 12) == 0)
1306 uint8_t cmd = (hdr.v2.ver_cmd & 0x0f);
1310 case 0x01: /* PROXY command */
1313 case 0x11: /* TCPv4 address type */
1315 tmpaddr.sin_addr.s_addr = hdr.v2.addr.ip4.src_addr;
1316 inet_ntop(AF_INET, &tmpaddr.sin_addr, CS &tmpip, sizeof(tmpip));
1317 if (!string_is_ip_address(US tmpip, NULL))
1319 DEBUG(D_receive) debug_printf("Invalid %s source IP\n", iptype);
1322 proxy_local_address = sender_host_address;
1323 sender_host_address = string_copy(US tmpip);
1324 tmpport = ntohs(hdr.v2.addr.ip4.src_port);
1325 proxy_local_port = sender_host_port;
1326 sender_host_port = tmpport;
1327 /* Save dest ip/port */
1328 tmpaddr.sin_addr.s_addr = hdr.v2.addr.ip4.dst_addr;
1329 inet_ntop(AF_INET, &tmpaddr.sin_addr, CS &tmpip, sizeof(tmpip));
1330 if (!string_is_ip_address(US tmpip, NULL))
1332 DEBUG(D_receive) debug_printf("Invalid %s dest port\n", iptype);
1335 proxy_external_address = string_copy(US tmpip);
1336 tmpport = ntohs(hdr.v2.addr.ip4.dst_port);
1337 proxy_external_port = tmpport;
1339 case 0x21: /* TCPv6 address type */
1341 memmove(tmpaddr6.sin6_addr.s6_addr, hdr.v2.addr.ip6.src_addr, 16);
1342 inet_ntop(AF_INET6, &tmpaddr6.sin6_addr, CS &tmpip6, sizeof(tmpip6));
1343 if (!string_is_ip_address(US tmpip6, NULL))
1345 DEBUG(D_receive) debug_printf("Invalid %s source IP\n", iptype);
1348 proxy_local_address = sender_host_address;
1349 sender_host_address = string_copy(US tmpip6);
1350 tmpport = ntohs(hdr.v2.addr.ip6.src_port);
1351 proxy_local_port = sender_host_port;
1352 sender_host_port = tmpport;
1353 /* Save dest ip/port */
1354 memmove(tmpaddr6.sin6_addr.s6_addr, hdr.v2.addr.ip6.dst_addr, 16);
1355 inet_ntop(AF_INET6, &tmpaddr6.sin6_addr, CS &tmpip6, sizeof(tmpip6));
1356 if (!string_is_ip_address(US tmpip6, NULL))
1358 DEBUG(D_receive) debug_printf("Invalid %s dest port\n", iptype);
1361 proxy_external_address = string_copy(US tmpip6);
1362 tmpport = ntohs(hdr.v2.addr.ip6.dst_port);
1363 proxy_external_port = tmpport;
1367 debug_printf("Unsupported PROXYv2 connection type: 0x%02x\n",
1371 /* Unsupported protocol, keep local connection address */
1373 case 0x00: /* LOCAL command */
1374 /* Keep local connection address for LOCAL */
1379 debug_printf("Unsupported PROXYv2 command: 0x%x\n", cmd);
1383 else if (ret >= 8 && memcmp(hdr.v1.line, "PROXY", 5) == 0)
1387 uschar *sp; /* Utility variables follow */
1392 /* get the rest of the line */
1393 r2 = swallow_until_crlf(fd, (uschar*)&hdr, ret, sizeof(hdr)-ret);
1398 p = string_copy(hdr.v1.line);
1399 end = memchr(p, '\r', ret - 1);
1401 if (!end || (end == (uschar*)&hdr + ret) || end[1] != '\n')
1403 DEBUG(D_receive) debug_printf("Partial or invalid PROXY header\n");
1406 *end = '\0'; /* Terminate the string */
1407 size = end + 2 - p; /* Skip header + CRLF */
1408 DEBUG(D_receive) debug_printf("Detected PROXYv1 header\n");
1409 DEBUG(D_receive) debug_printf("Bytes read not within PROXY header: %d\n", ret - size);
1410 /* Step through the string looking for the required fields. Ensure
1411 strict adherence to required formatting, exit for any error. */
1413 if (!isspace(*(p++)))
1415 DEBUG(D_receive) debug_printf("Missing space after PROXY command\n");
1418 if (!Ustrncmp(p, CCS"TCP4", 4))
1420 else if (!Ustrncmp(p,CCS"TCP6", 4))
1422 else if (!Ustrncmp(p,CCS"UNKNOWN", 7))
1424 iptype = US"Unknown";
1429 DEBUG(D_receive) debug_printf("Invalid TCP type\n");
1433 p += Ustrlen(iptype);
1434 if (!isspace(*(p++)))
1436 DEBUG(D_receive) debug_printf("Missing space after TCP4/6 command\n");
1439 /* Find the end of the arg */
1440 if ((sp = Ustrchr(p, ' ')) == NULL)
1443 debug_printf("Did not find proxied src %s\n", iptype);
1447 if(!string_is_ip_address(p, NULL))
1450 debug_printf("Proxied src arg is not an %s address\n", iptype);
1453 proxy_local_address = sender_host_address;
1454 sender_host_address = p;
1456 if ((sp = Ustrchr(p, ' ')) == NULL)
1459 debug_printf("Did not find proxy dest %s\n", iptype);
1463 if(!string_is_ip_address(p, NULL))
1466 debug_printf("Proxy dest arg is not an %s address\n", iptype);
1469 proxy_external_address = p;
1471 if ((sp = Ustrchr(p, ' ')) == NULL)
1473 DEBUG(D_receive) debug_printf("Did not find proxied src port\n");
1477 tmp_port = strtol(CCS p, &endc, 10);
1478 if (*endc || tmp_port == 0)
1481 debug_printf("Proxied src port '%s' not an integer\n", p);
1484 proxy_local_port = sender_host_port;
1485 sender_host_port = tmp_port;
1487 if ((sp = Ustrchr(p, '\0')) == NULL)
1489 DEBUG(D_receive) debug_printf("Did not find proxy dest port\n");
1492 tmp_port = strtol(CCS p, &endc, 10);
1493 if (*endc || tmp_port == 0)
1496 debug_printf("Proxy dest port '%s' not an integer\n", p);
1499 proxy_external_port = tmp_port;
1500 /* Already checked for /r /n above. Good V1 header received. */
1504 /* Wrong protocol */
1505 DEBUG(D_receive) debug_printf("Invalid proxy protocol version negotiation\n");
1506 (void) swallow_until_crlf(fd, (uschar*)&hdr, ret, sizeof(hdr)-ret);
1512 debug_printf("Valid %s sender from Proxy Protocol header\n", iptype);
1513 yield = proxy_session;
1515 /* Don't flush any potential buffer contents. Any input on proxyfail
1516 should cause a synchronization failure */
1519 restore_socket_timeout(fd, get_ok, &tvtmp, vslen);
1524 sender_host_name = NULL;
1525 (void) host_name_lookup();
1526 host_build_sender_fullhost();
1530 f.proxy_session_failed = TRUE;
1532 debug_printf("Failure to extract proxied host, only QUIT allowed\n");
1539 /*************************************************
1540 * Read one command line *
1541 *************************************************/
1543 /* Strictly, SMTP commands coming over the net are supposed to end with CRLF.
1544 There are sites that don't do this, and in any case internal SMTP probably
1545 should check only for LF. Consequently, we check here for LF only. The line
1546 ends up with [CR]LF removed from its end. If we get an overlong line, treat as
1547 an unknown command. The command is read into the global smtp_cmd_buffer so that
1548 it is available via $smtp_command.
1550 The character reading routine sets up a timeout for each block actually read
1551 from the input (which may contain more than one command). We set up a special
1552 signal handler that closes down the session on a timeout. Control does not
1553 return when it runs.
1556 check_sync if TRUE, check synchronization rules if global option is TRUE
1557 buffer_lim maximum to buffer in lower layer
1559 Returns: a code identifying the command (enumerated above)
1563 smtp_read_command(BOOL check_sync, unsigned buffer_lim)
1568 BOOL hadnull = FALSE;
1570 had_command_timeout = 0;
1571 os_non_restarting_signal(SIGALRM, command_timeout_handler);
1573 while ((c = (receive_getc)(buffer_lim)) != '\n' && c != EOF)
1575 if (ptr >= SMTP_CMD_BUFFER_SIZE)
1577 os_non_restarting_signal(SIGALRM, sigalrm_handler);
1585 smtp_cmd_buffer[ptr++] = c;
1588 receive_linecount++; /* For BSMTP errors */
1589 os_non_restarting_signal(SIGALRM, sigalrm_handler);
1591 /* If hit end of file, return pseudo EOF command. Whether we have a
1592 part-line already read doesn't matter, since this is an error state. */
1594 if (c == EOF) return EOF_CMD;
1596 /* Remove any CR and white space at the end of the line, and terminate the
1599 while (ptr > 0 && isspace(smtp_cmd_buffer[ptr-1])) ptr--;
1600 smtp_cmd_buffer[ptr] = 0;
1602 DEBUG(D_receive) debug_printf("SMTP<< %s\n", smtp_cmd_buffer);
1604 /* NULLs are not allowed in SMTP commands */
1606 if (hadnull) return BADCHAR_CMD;
1608 /* Scan command list and return identity, having set the data pointer
1609 to the start of the actual data characters. Check for SMTP synchronization
1612 for (p = cmd_list; p < cmd_list_end; p++)
1614 #ifdef SUPPORT_PROXY
1615 /* Only allow QUIT command if Proxy Protocol parsing failed */
1616 if (proxy_session && f.proxy_session_failed && p->cmd != QUIT_CMD)
1620 && strncmpic(smtp_cmd_buffer, US p->name, p->len) == 0
1621 && ( smtp_cmd_buffer[p->len-1] == ':' /* "mail from:" or "rcpt to:" */
1622 || smtp_cmd_buffer[p->len] == 0
1623 || smtp_cmd_buffer[p->len] == ' '
1626 if (smtp_inptr < smtp_inend && /* Outstanding input */
1627 p->cmd < sync_cmd_limit && /* Command should sync */
1628 check_sync && /* Local flag set */
1629 smtp_enforce_sync && /* Global flag set */
1630 sender_host_address != NULL && /* Not local input */
1631 !f.sender_host_notsocket) /* Really is a socket */
1634 /* The variables $smtp_command and $smtp_command_argument point into the
1635 unmodified input buffer. A copy of the latter is taken for actual
1636 processing, so that it can be chopped up into separate parts if necessary,
1637 for example, when processing a MAIL command options such as SIZE that can
1638 follow the sender address. */
1640 smtp_cmd_argument = smtp_cmd_buffer + p->len;
1641 while (isspace(*smtp_cmd_argument)) smtp_cmd_argument++;
1642 Ustrcpy(smtp_data_buffer, smtp_cmd_argument);
1643 smtp_cmd_data = smtp_data_buffer;
1645 /* Count non-mail commands from those hosts that are controlled in this
1646 way. The default is all hosts. We don't waste effort checking the list
1647 until we get a non-mail command, but then cache the result to save checking
1648 again. If there's a DEFER while checking the host, assume it's in the list.
1650 Note that one instance of RSET, EHLO/HELO, and STARTTLS is allowed at the
1651 start of each incoming message by fiddling with the value in the table. */
1653 if (!p->is_mail_cmd)
1655 if (count_nonmail == TRUE_UNSET) count_nonmail =
1656 verify_check_host(&smtp_accept_max_nonmail_hosts) != FAIL;
1657 if (count_nonmail && ++nonmail_command_count > smtp_accept_max_nonmail)
1658 return TOO_MANY_NONMAIL_CMD;
1661 /* If there is data for a command that does not expect it, generate the
1664 return (p->has_arg || *smtp_cmd_data == 0)? p->cmd : BADARG_CMD;
1668 #ifdef SUPPORT_PROXY
1669 /* Only allow QUIT command if Proxy Protocol parsing failed */
1670 if (proxy_session && f.proxy_session_failed)
1671 return PROXY_FAIL_IGNORE_CMD;
1674 /* Enforce synchronization for unknown commands */
1676 if ( smtp_inptr < smtp_inend /* Outstanding input */
1677 && check_sync /* Local flag set */
1678 && smtp_enforce_sync /* Global flag set */
1679 && sender_host_address /* Not local input */
1680 && !f.sender_host_notsocket) /* Really is a socket */
1688 /*************************************************
1689 * Forced closedown of call *
1690 *************************************************/
1692 /* This function is called from log.c when Exim is dying because of a serious
1693 disaster, and also from some other places. If an incoming non-batched SMTP
1694 channel is open, it swallows the rest of the incoming message if in the DATA
1695 phase, sends the reply string, and gives an error to all subsequent commands
1696 except QUIT. The existence of an SMTP call is detected by the non-NULLness of
1700 message SMTP reply string to send, excluding the code
1706 smtp_closedown(uschar *message)
1708 if (!smtp_in || smtp_batched_input) return;
1709 receive_swallow_smtp();
1710 smtp_printf("421 %s\r\n", FALSE, message);
1712 for (;;) switch(smtp_read_command(FALSE, GETC_BUFFER_UNLIMITED))
1718 smtp_printf("221 %s closing connection\r\n", FALSE, smtp_active_hostname);
1723 smtp_printf("250 Reset OK\r\n", FALSE);
1727 smtp_printf("421 %s\r\n", FALSE, message);
1735 /*************************************************
1736 * Set up connection info for logging *
1737 *************************************************/
1739 /* This function is called when logging information about an SMTP connection.
1740 It sets up appropriate source information, depending on the type of connection.
1741 If sender_fullhost is NULL, we are at a very early stage of the connection;
1742 just use the IP address.
1745 Returns: a string describing the connection
1749 smtp_get_connection_info(void)
1751 const uschar * hostname = sender_fullhost
1752 ? sender_fullhost : sender_host_address;
1755 return string_sprintf("SMTP connection from %s", hostname);
1757 if (f.sender_host_unknown || f.sender_host_notsocket)
1758 return string_sprintf("SMTP connection from %s", sender_ident);
1761 return string_sprintf("SMTP connection from %s (via inetd)", hostname);
1763 if (LOGGING(incoming_interface) && interface_address != NULL)
1764 return string_sprintf("SMTP connection from %s I=[%s]:%d", hostname,
1765 interface_address, interface_port);
1767 return string_sprintf("SMTP connection from %s", hostname);
1773 /* Append TLS-related information to a log line
1776 g String under construction: allocated string to extend, or NULL
1778 Returns: Allocated string or NULL
1781 s_tlslog(gstring * g)
1783 if (LOGGING(tls_cipher) && tls_in.cipher)
1784 g = string_append(g, 2, US" X=", tls_in.cipher);
1785 if (LOGGING(tls_certificate_verified) && tls_in.cipher)
1786 g = string_append(g, 2, US" CV=", tls_in.certificate_verified? "yes":"no");
1787 if (LOGGING(tls_peerdn) && tls_in.peerdn)
1788 g = string_append(g, 3, US" DN=\"", string_printing(tls_in.peerdn), US"\"");
1789 if (LOGGING(tls_sni) && tls_in.sni)
1790 g = string_append(g, 3, US" SNI=\"", string_printing(tls_in.sni), US"\"");
1795 /*************************************************
1796 * Log lack of MAIL if so configured *
1797 *************************************************/
1799 /* This function is called when an SMTP session ends. If the log selector
1800 smtp_no_mail is set, write a log line giving some details of what has happened
1801 in the SMTP session.
1808 smtp_log_no_mail(void)
1814 if (smtp_mailcmd_count > 0 || !LOGGING(smtp_no_mail))
1817 if (sender_host_authenticated)
1819 g = string_append(g, 2, US" A=", sender_host_authenticated);
1820 if (authenticated_id) g = string_append(g, 2, US":", authenticated_id);
1827 sep = smtp_connection_had[SMTP_HBUFF_SIZE-1] != SCH_NONE ? US" C=..." : US" C=";
1829 for (i = smtp_ch_index; i < SMTP_HBUFF_SIZE; i++)
1830 if (smtp_connection_had[i] != SCH_NONE)
1832 g = string_append(g, 2, sep, smtp_names[smtp_connection_had[i]]);
1836 for (i = 0; i < smtp_ch_index; i++)
1838 g = string_append(g, 2, sep, smtp_names[smtp_connection_had[i]]);
1842 if (!(s = string_from_gstring(g))) s = US"";
1844 log_write(0, LOG_MAIN, "no MAIL in %sSMTP connection from %s D=%s%s",
1845 f.tcp_in_fastopen ? US"TFO " : US"",
1846 host_and_ident(FALSE), string_timesince(&smtp_connection_start), s);
1850 /* Return list of recent smtp commands */
1856 gstring * list = NULL;
1859 for (i = smtp_ch_index; i < SMTP_HBUFF_SIZE; i++)
1860 if (smtp_connection_had[i] != SCH_NONE)
1861 list = string_append_listele(list, ',', smtp_names[smtp_connection_had[i]]);
1863 for (i = 0; i < smtp_ch_index; i++)
1864 list = string_append_listele(list, ',', smtp_names[smtp_connection_had[i]]);
1866 s = string_from_gstring(list);
1867 return s ? s : US"";
1873 /*************************************************
1874 * Check HELO line and set sender_helo_name *
1875 *************************************************/
1877 /* Check the format of a HELO line. The data for HELO/EHLO is supposed to be
1878 the domain name of the sending host, or an ip literal in square brackets. The
1879 argument is placed in sender_helo_name, which is in malloc store, because it
1880 must persist over multiple incoming messages. If helo_accept_junk is set, this
1881 host is permitted to send any old junk (needed for some broken hosts).
1882 Otherwise, helo_allow_chars can be used for rogue characters in general
1883 (typically people want to let in underscores).
1886 s the data portion of the line (already past any white space)
1888 Returns: TRUE or FALSE
1892 check_helo(uschar *s)
1895 uschar *end = s + Ustrlen(s);
1896 BOOL yield = fl.helo_accept_junk;
1898 /* Discard any previous helo name */
1900 if (sender_helo_name)
1902 store_free(sender_helo_name);
1903 sender_helo_name = NULL;
1906 /* Skip tests if junk is permitted. */
1910 /* Allow the new standard form for IPv6 address literals, namely,
1911 [IPv6:....], and because someone is bound to use it, allow an equivalent
1912 IPv4 form. Allow plain addresses as well. */
1919 if (strncmpic(s, US"[IPv6:", 6) == 0)
1920 yield = (string_is_ip_address(s+6, NULL) == 6);
1921 else if (strncmpic(s, US"[IPv4:", 6) == 0)
1922 yield = (string_is_ip_address(s+6, NULL) == 4);
1924 yield = (string_is_ip_address(s+1, NULL) != 0);
1929 /* Non-literals must be alpha, dot, hyphen, plus any non-valid chars
1930 that have been configured (usually underscore - sigh). */
1933 for (yield = TRUE; *s; s++)
1934 if (!isalnum(*s) && *s != '.' && *s != '-' &&
1935 Ustrchr(helo_allow_chars, *s) == NULL)
1941 /* Save argument if OK */
1943 if (yield) sender_helo_name = string_copy_malloc(start);
1951 /*************************************************
1952 * Extract SMTP command option *
1953 *************************************************/
1955 /* This function picks the next option setting off the end of smtp_cmd_data. It
1956 is called for MAIL FROM and RCPT TO commands, to pick off the optional ESMTP
1957 things that can appear there.
1960 name point this at the name
1961 value point this at the data string
1963 Returns: TRUE if found an option
1967 extract_option(uschar **name, uschar **value)
1970 uschar *v = smtp_cmd_data + Ustrlen(smtp_cmd_data) - 1;
1971 while (isspace(*v)) v--;
1973 while (v > smtp_cmd_data && *v != '=' && !isspace(*v))
1975 /* Take care to not stop at a space embedded in a quoted local-part */
1977 if (*v == '"') do v--; while (*v != '"' && v > smtp_cmd_data+1);
1984 while(isalpha(n[-1])) n--;
1985 /* RFC says SP, but TAB seen in wild and other major MTAs accept it */
1986 if (!isspace(n[-1])) return FALSE;
1992 if (v == smtp_cmd_data) return FALSE;
2004 /*************************************************
2005 * Reset for new message *
2006 *************************************************/
2008 /* This function is called whenever the SMTP session is reset from
2009 within either of the setup functions; also from the daemon loop.
2011 Argument: the stacking pool storage reset point
2016 smtp_reset(void *reset_point)
2018 recipients_list = NULL;
2019 rcpt_count = rcpt_defer_count = rcpt_fail_count =
2020 raw_recipients_count = recipients_count = recipients_list_max = 0;
2021 message_linecount = 0;
2023 acl_added_headers = NULL;
2024 acl_removed_headers = NULL;
2025 f.queue_only_policy = FALSE;
2026 rcpt_smtp_response = NULL;
2027 fl.rcpt_smtp_response_same = TRUE;
2028 fl.rcpt_in_progress = FALSE;
2029 f.deliver_freeze = FALSE; /* Can be set by ACL */
2030 freeze_tell = freeze_tell_config; /* Can be set by ACL */
2031 fake_response = OK; /* Can be set by ACL */
2032 #ifdef WITH_CONTENT_SCAN
2033 f.no_mbox_unspool = FALSE; /* Can be set by ACL */
2035 f.submission_mode = FALSE; /* Can be set by ACL */
2036 f.suppress_local_fixups = f.suppress_local_fixups_default; /* Can be set by ACL */
2037 f.active_local_from_check = local_from_check; /* Can be set by ACL */
2038 f.active_local_sender_retain = local_sender_retain; /* Can be set by ACL */
2039 sending_ip_address = NULL;
2040 return_path = sender_address = NULL;
2041 sender_data = NULL; /* Can be set by ACL */
2042 deliver_localpart_parent = deliver_localpart_orig = NULL;
2043 deliver_domain_parent = deliver_domain_orig = NULL;
2044 callout_address = NULL;
2045 submission_name = NULL; /* Can be set by ACL */
2046 raw_sender = NULL; /* After SMTP rewrite, before qualifying */
2047 sender_address_unrewritten = NULL; /* Set only after verify rewrite */
2048 sender_verified_list = NULL; /* No senders verified */
2049 memset(sender_address_cache, 0, sizeof(sender_address_cache));
2050 memset(sender_domain_cache, 0, sizeof(sender_domain_cache));
2052 authenticated_sender = NULL;
2053 #ifdef EXPERIMENTAL_BRIGHTMAIL
2055 bmi_verdicts = NULL;
2057 dnslist_domain = dnslist_matched = NULL;
2059 spf_header_comment = spf_received = spf_result = spf_smtp_comment = NULL;
2060 spf_result_guessed = FALSE;
2062 #ifndef DISABLE_DKIM
2063 dkim_cur_signer = dkim_signers =
2064 dkim_signing_domain = dkim_signing_selector = dkim_signatures = NULL;
2065 dkim_cur_signer = dkim_signers = dkim_signing_domain = dkim_signing_selector = NULL;
2066 f.dkim_disable_verify = FALSE;
2067 dkim_collect_input = 0;
2068 dkim_verify_overall = dkim_verify_status = dkim_verify_reason = NULL;
2069 dkim_key_length = 0;
2070 dkim_verify_signers = US"$dkim_signers";
2072 #ifdef EXPERIMENTAL_DMARC
2073 f.dmarc_has_been_checked = f.dmarc_disable_verify = f.dmarc_enable_forensic = FALSE;
2074 dmarc_domain_policy = dmarc_status = dmarc_status_text =
2075 dmarc_used_domain = NULL;
2077 #ifdef EXPERIMENTAL_ARC
2078 arc_state = arc_state_reason = NULL;
2082 deliver_host = deliver_host_address = NULL; /* Can be set by ACL */
2083 #ifndef DISABLE_PRDR
2084 prdr_requested = FALSE;
2087 message_smtputf8 = FALSE;
2089 body_linecount = body_zerocount = 0;
2091 sender_rate = sender_rate_limit = sender_rate_period = NULL;
2092 ratelimiters_mail = NULL; /* Updated by ratelimit ACL condition */
2093 /* Note that ratelimiters_conn persists across resets. */
2095 /* Reset message ACL variables */
2099 /* The message body variables use malloc store. They may be set if this is
2100 not the first message in an SMTP session and the previous message caused them
2101 to be referenced in an ACL. */
2105 store_free(message_body);
2106 message_body = NULL;
2109 if (message_body_end)
2111 store_free(message_body_end);
2112 message_body_end = NULL;
2115 /* Warning log messages are also saved in malloc store. They are saved to avoid
2116 repetition in the same message, but it seems right to repeat them for different
2119 while (acl_warn_logged)
2121 string_item *this = acl_warn_logged;
2122 acl_warn_logged = acl_warn_logged->next;
2125 store_reset(reset_point);
2132 /*************************************************
2133 * Initialize for incoming batched SMTP message *
2134 *************************************************/
2136 /* This function is called from smtp_setup_msg() in the case when
2137 smtp_batched_input is true. This happens when -bS is used to pass a whole batch
2138 of messages in one file with SMTP commands between them. All errors must be
2139 reported by sending a message, and only MAIL FROM, RCPT TO, and DATA are
2140 relevant. After an error on a sender, or an invalid recipient, the remainder
2141 of the message is skipped. The value of received_protocol is already set.
2144 Returns: > 0 message successfully started (reached DATA)
2145 = 0 QUIT read or end of file reached
2146 < 0 should not occur
2150 smtp_setup_batch_msg(void)
2153 void *reset_point = store_get(0);
2155 /* Save the line count at the start of each transaction - single commands
2156 like HELO and RSET count as whole transactions. */
2158 bsmtp_transaction_linecount = receive_linecount;
2160 if ((receive_feof)()) return 0; /* Treat EOF as QUIT */
2162 cancel_cutthrough_connection(TRUE, US"smtp_setup_batch_msg");
2163 smtp_reset(reset_point); /* Reset for start of message */
2165 /* Deal with SMTP commands. This loop is exited by setting done to a POSITIVE
2166 value. The values are 2 larger than the required yield of the function. */
2171 uschar *recipient = NULL;
2172 int start, end, sender_domain, recipient_domain;
2174 switch(smtp_read_command(FALSE, GETC_BUFFER_UNLIMITED))
2176 /* The HELO/EHLO commands set sender_address_helo if they have
2177 valid data; otherwise they are ignored, except that they do
2178 a reset of the state. */
2183 check_helo(smtp_cmd_data);
2187 cancel_cutthrough_connection(TRUE, US"RSET received");
2188 smtp_reset(reset_point);
2189 bsmtp_transaction_linecount = receive_linecount;
2193 /* The MAIL FROM command requires an address as an operand. All we
2194 do here is to parse it for syntactic correctness. The form "<>" is
2195 a special case which converts into an empty string. The start/end
2196 pointers in the original are not used further for this address, as
2197 it is the canonical extracted address which is all that is kept. */
2200 smtp_mailcmd_count++; /* Count for no-mail log */
2201 if (sender_address != NULL)
2202 /* The function moan_smtp_batch() does not return. */
2203 moan_smtp_batch(smtp_cmd_buffer, "503 Sender already given");
2205 if (smtp_cmd_data[0] == 0)
2206 /* The function moan_smtp_batch() does not return. */
2207 moan_smtp_batch(smtp_cmd_buffer, "501 MAIL FROM must have an address operand");
2209 /* Reset to start of message */
2211 cancel_cutthrough_connection(TRUE, US"MAIL received");
2212 smtp_reset(reset_point);
2214 /* Apply SMTP rewrite */
2216 raw_sender = ((rewrite_existflags & rewrite_smtp) != 0)?
2217 rewrite_one(smtp_cmd_data, rewrite_smtp|rewrite_smtp_sender, NULL, FALSE,
2218 US"", global_rewrite_rules) : smtp_cmd_data;
2220 /* Extract the address; the TRUE flag allows <> as valid */
2223 parse_extract_address(raw_sender, &errmess, &start, &end, &sender_domain,
2227 /* The function moan_smtp_batch() does not return. */
2228 moan_smtp_batch(smtp_cmd_buffer, "501 %s", errmess);
2230 sender_address = string_copy(raw_sender);
2232 /* Qualify unqualified sender addresses if permitted to do so. */
2235 && sender_address[0] != 0 && sender_address[0] != '@')
2236 if (f.allow_unqualified_sender)
2238 sender_address = rewrite_address_qualify(sender_address, FALSE);
2239 DEBUG(D_receive) debug_printf("unqualified address %s accepted "
2240 "and rewritten\n", raw_sender);
2242 /* The function moan_smtp_batch() does not return. */
2244 moan_smtp_batch(smtp_cmd_buffer, "501 sender address must contain "
2249 /* The RCPT TO command requires an address as an operand. All we do
2250 here is to parse it for syntactic correctness. There may be any number
2251 of RCPT TO commands, specifying multiple senders. We build them all into
2252 a data structure that is in argc/argv format. The start/end values
2253 given by parse_extract_address are not used, as we keep only the
2254 extracted address. */
2257 if (!sender_address)
2258 /* The function moan_smtp_batch() does not return. */
2259 moan_smtp_batch(smtp_cmd_buffer, "503 No sender yet given");
2261 if (smtp_cmd_data[0] == 0)
2262 /* The function moan_smtp_batch() does not return. */
2263 moan_smtp_batch(smtp_cmd_buffer,
2264 "501 RCPT TO must have an address operand");
2266 /* Check maximum number allowed */
2268 if (recipients_max > 0 && recipients_count + 1 > recipients_max)
2269 /* The function moan_smtp_batch() does not return. */
2270 moan_smtp_batch(smtp_cmd_buffer, "%s too many recipients",
2271 recipients_max_reject? "552": "452");
2273 /* Apply SMTP rewrite, then extract address. Don't allow "<>" as a
2274 recipient address */
2276 recipient = rewrite_existflags & rewrite_smtp
2277 ? rewrite_one(smtp_cmd_data, rewrite_smtp, NULL, FALSE, US"",
2278 global_rewrite_rules)
2281 recipient = parse_extract_address(recipient, &errmess, &start, &end,
2282 &recipient_domain, FALSE);
2285 /* The function moan_smtp_batch() does not return. */
2286 moan_smtp_batch(smtp_cmd_buffer, "501 %s", errmess);
2288 /* If the recipient address is unqualified, qualify it if permitted. Then
2289 add it to the list of recipients. */
2291 if (!recipient_domain)
2292 if (f.allow_unqualified_recipient)
2294 DEBUG(D_receive) debug_printf("unqualified address %s accepted\n",
2296 recipient = rewrite_address_qualify(recipient, TRUE);
2298 /* The function moan_smtp_batch() does not return. */
2300 moan_smtp_batch(smtp_cmd_buffer,
2301 "501 recipient address must contain a domain");
2303 receive_add_recipient(recipient, -1);
2307 /* The DATA command is legal only if it follows successful MAIL FROM
2308 and RCPT TO commands. This function is complete when a valid DATA
2309 command is encountered. */
2312 if (!sender_address || recipients_count <= 0)
2313 /* The function moan_smtp_batch() does not return. */
2314 if (!sender_address)
2315 moan_smtp_batch(smtp_cmd_buffer,
2316 "503 MAIL FROM:<sender> command must precede DATA");
2318 moan_smtp_batch(smtp_cmd_buffer,
2319 "503 RCPT TO:<recipient> must precede DATA");
2322 done = 3; /* DATA successfully achieved */
2323 message_ended = END_NOTENDED; /* Indicate in middle of message */
2328 /* The VRFY, EXPN, HELP, ETRN, and NOOP commands are ignored. */
2335 bsmtp_transaction_linecount = receive_linecount;
2346 /* The function moan_smtp_batch() does not return. */
2347 moan_smtp_batch(smtp_cmd_buffer, "501 Unexpected argument data");
2352 /* The function moan_smtp_batch() does not return. */
2353 moan_smtp_batch(smtp_cmd_buffer, "501 Unexpected NULL in SMTP command");
2358 /* The function moan_smtp_batch() does not return. */
2359 moan_smtp_batch(smtp_cmd_buffer, "500 Command unrecognized");
2364 return done - 2; /* Convert yield values */
2371 smtp_log_tls_fail(uschar * errstr)
2373 uschar * conn_info = smtp_get_connection_info();
2375 if (Ustrncmp(conn_info, US"SMTP ", 5) == 0) conn_info += 5;
2376 /* I'd like to get separated H= here, but too hard for now */
2378 log_write(0, LOG_MAIN, "TLS error on %s %s", conn_info, errstr);
2390 struct tcp_info tinfo;
2391 socklen_t len = sizeof(tinfo);
2393 if ( getsockopt(fileno(smtp_out), IPPROTO_TCP, TCP_INFO, &tinfo, &len) == 0
2394 && tinfo.tcpi_state == TCP_SYN_RECV
2397 DEBUG(D_receive) debug_printf("TCP_FASTOPEN mode connection (state TCP_SYN_RECV)\n");
2398 f.tcp_in_fastopen = TRUE;
2405 /*************************************************
2406 * Start an SMTP session *
2407 *************************************************/
2409 /* This function is called at the start of an SMTP session. Thereafter,
2410 smtp_setup_msg() is called to initiate each separate message. This
2411 function does host-specific testing, and outputs the banner line.
2414 Returns: FALSE if the session can not continue; something has
2415 gone wrong, or the connection to the host is blocked
2419 smtp_start_session(void)
2422 uschar *user_msg, *log_msg;
2427 gettimeofday(&smtp_connection_start, NULL);
2428 for (smtp_ch_index = 0; smtp_ch_index < SMTP_HBUFF_SIZE; smtp_ch_index++)
2429 smtp_connection_had[smtp_ch_index] = SCH_NONE;
2432 /* Default values for certain variables */
2434 fl.helo_seen = fl.esmtp = fl.helo_accept_junk = FALSE;
2435 smtp_mailcmd_count = 0;
2436 count_nonmail = TRUE_UNSET;
2437 synprot_error_count = unknown_command_count = nonmail_command_count = 0;
2438 smtp_delay_mail = smtp_rlm_base;
2439 fl.auth_advertised = FALSE;
2440 f.smtp_in_pipelining_advertised = f.smtp_in_pipelining_used = FALSE;
2441 f.pipelining_enable = TRUE;
2442 sync_cmd_limit = NON_SYNC_CMD_NON_PIPELINING;
2443 fl.smtp_exit_function_called = FALSE; /* For avoiding loop in not-quit exit */
2445 /* If receiving by -bs from a trusted user, or testing with -bh, we allow
2446 authentication settings from -oMaa to remain in force. */
2448 if (!host_checking && !f.sender_host_notsocket)
2449 sender_host_auth_pubname = sender_host_authenticated = NULL;
2450 authenticated_by = NULL;
2453 tls_in.cipher = tls_in.peerdn = NULL;
2454 tls_in.ourcert = tls_in.peercert = NULL;
2456 tls_in.ocsp = OCSP_NOT_REQ;
2457 fl.tls_advertised = FALSE;
2458 # ifdef EXPERIMENTAL_REQUIRETLS
2459 fl.requiretls_advertised = FALSE;
2462 fl.dsn_advertised = FALSE;
2464 fl.smtputf8_advertised = FALSE;
2467 /* Reset ACL connection variables */
2471 /* Allow for trailing 0 in the command and data buffers. */
2473 if (!(smtp_cmd_buffer = US malloc(2*SMTP_CMD_BUFFER_SIZE + 2)))
2474 log_write(0, LOG_MAIN|LOG_PANIC_DIE,
2475 "malloc() failed for SMTP command buffer");
2477 smtp_cmd_buffer[0] = 0;
2478 smtp_data_buffer = smtp_cmd_buffer + SMTP_CMD_BUFFER_SIZE + 1;
2480 /* For batched input, the protocol setting can be overridden from the
2481 command line by a trusted caller. */
2483 if (smtp_batched_input)
2485 if (!received_protocol) received_protocol = US"local-bsmtp";
2488 /* For non-batched SMTP input, the protocol setting is forced here. It will be
2489 reset later if any of EHLO/AUTH/STARTTLS are received. */
2493 (sender_host_address ? protocols : protocols_local) [pnormal];
2495 /* Set up the buffer for inputting using direct read() calls, and arrange to
2496 call the local functions instead of the standard C ones. Place a NUL at the
2497 end of the buffer to safety-stop C-string reads from it. */
2499 if (!(smtp_inbuffer = US malloc(IN_BUFFER_SIZE)))
2500 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "malloc() failed for SMTP input buffer");
2501 smtp_inbuffer[IN_BUFFER_SIZE-1] = '\0';
2503 receive_getc = smtp_getc;
2504 receive_getbuf = smtp_getbuf;
2505 receive_get_cache = smtp_get_cache;
2506 receive_ungetc = smtp_ungetc;
2507 receive_feof = smtp_feof;
2508 receive_ferror = smtp_ferror;
2509 receive_smtp_buffered = smtp_buffered;
2510 smtp_inptr = smtp_inend = smtp_inbuffer;
2511 smtp_had_eof = smtp_had_error = 0;
2513 /* Set up the message size limit; this may be host-specific */
2515 thismessage_size_limit = expand_string_integer(message_size_limit, TRUE);
2516 if (expand_string_message)
2518 if (thismessage_size_limit == -1)
2519 log_write(0, LOG_MAIN|LOG_PANIC, "unable to expand message_size_limit: "
2520 "%s", expand_string_message);
2522 log_write(0, LOG_MAIN|LOG_PANIC, "invalid message_size_limit: "
2523 "%s", expand_string_message);
2524 smtp_closedown(US"Temporary local problem - please try later");
2528 /* When a message is input locally via the -bs or -bS options, sender_host_
2529 unknown is set unless -oMa was used to force an IP address, in which case it
2530 is checked like a real remote connection. When -bs is used from inetd, this
2531 flag is not set, causing the sending host to be checked. The code that deals
2532 with IP source routing (if configured) is never required for -bs or -bS and
2533 the flag sender_host_notsocket is used to suppress it.
2535 If smtp_accept_max and smtp_accept_reserve are set, keep some connections in
2536 reserve for certain hosts and/or networks. */
2538 if (!f.sender_host_unknown)
2541 BOOL reserved_host = FALSE;
2543 /* Look up IP options (source routing info) on the socket if this is not an
2544 -oMa "host", and if any are found, log them and drop the connection.
2546 Linux (and others now, see below) is different to everyone else, so there
2547 has to be some conditional compilation here. Versions of Linux before 2.1.15
2548 used a structure whose name was "options". Somebody finally realized that
2549 this name was silly, and it got changed to "ip_options". I use the
2550 newer name here, but there is a fudge in the script that sets up os.h
2551 to define a macro in older Linux systems.
2553 Sigh. Linux is a fast-moving target. Another generation of Linux uses
2554 glibc 2, which has chosen ip_opts for the structure name. This is now
2555 really a glibc thing rather than a Linux thing, so the condition name
2556 has been changed to reflect this. It is relevant also to GNU/Hurd.
2558 Mac OS 10.x (Darwin) is like the later glibc versions, but without the
2559 setting of the __GLIBC__ macro, so we can't detect it automatically. There's
2560 a special macro defined in the os.h file.
2562 Some DGUX versions on older hardware appear not to support IP options at
2563 all, so there is now a general macro which can be set to cut out this
2566 How to do this properly in IPv6 is not yet known. */
2568 #if !HAVE_IPV6 && !defined(NO_IP_OPTIONS)
2570 #ifdef GLIBC_IP_OPTIONS
2571 #if (!defined __GLIBC__) || (__GLIBC__ < 2)
2576 #elif defined DARWIN_IP_OPTIONS
2582 if (!host_checking && !f.sender_host_notsocket)
2585 EXIM_SOCKLEN_T optlen = sizeof(struct ip_options) + MAX_IPOPTLEN;
2586 struct ip_options *ipopt = store_get(optlen);
2588 struct ip_opts ipoptblock;
2589 struct ip_opts *ipopt = &ipoptblock;
2590 EXIM_SOCKLEN_T optlen = sizeof(ipoptblock);
2592 struct ipoption ipoptblock;
2593 struct ipoption *ipopt = &ipoptblock;
2594 EXIM_SOCKLEN_T optlen = sizeof(ipoptblock);
2597 /* Occasional genuine failures of getsockopt() have been seen - for
2598 example, "reset by peer". Therefore, just log and give up on this
2599 call, unless the error is ENOPROTOOPT. This error is given by systems
2600 that have the interfaces but not the mechanism - e.g. GNU/Hurd at the time
2601 of writing. So for that error, carry on - we just can't do an IP options
2604 DEBUG(D_receive) debug_printf("checking for IP options\n");
2606 if (getsockopt(fileno(smtp_out), IPPROTO_IP, IP_OPTIONS, US (ipopt),
2609 if (errno != ENOPROTOOPT)
2611 log_write(0, LOG_MAIN, "getsockopt() failed from %s: %s",
2612 host_and_ident(FALSE), strerror(errno));
2613 smtp_printf("451 SMTP service not available\r\n", FALSE);
2618 /* Deal with any IP options that are set. On the systems I have looked at,
2619 the value of MAX_IPOPTLEN has been 40, meaning that there should never be
2620 more logging data than will fit in big_buffer. Nevertheless, after somebody
2621 questioned this code, I've added in some paranoid checking. */
2623 else if (optlen > 0)
2625 uschar *p = big_buffer;
2626 uschar *pend = big_buffer + big_buffer_size;
2627 uschar *opt, *adptr;
2629 struct in_addr addr;
2632 uschar *optstart = US (ipopt->__data);
2634 uschar *optstart = US (ipopt->ip_opts);
2636 uschar *optstart = US (ipopt->ipopt_list);
2639 DEBUG(D_receive) debug_printf("IP options exist\n");
2641 Ustrcpy(p, "IP options on incoming call:");
2644 for (opt = optstart; opt != NULL &&
2645 opt < US (ipopt) + optlen;)
2659 if (!string_format(p, pend-p, " %s [@%s",
2660 (*opt == IPOPT_SSRR)? "SSRR" : "LSRR",
2662 inet_ntoa(*((struct in_addr *)(&(ipopt->faddr))))))
2664 inet_ntoa(ipopt->ip_dst)))
2666 inet_ntoa(ipopt->ipopt_dst)))
2674 optcount = (opt[1] - 3) / sizeof(struct in_addr);
2676 while (optcount-- > 0)
2678 memcpy(&addr, adptr, sizeof(addr));
2679 if (!string_format(p, pend - p - 1, "%s%s",
2680 (optcount == 0)? ":" : "@", inet_ntoa(addr)))
2686 adptr += sizeof(struct in_addr);
2695 if (pend - p < 4 + 3*opt[1]) { opt = NULL; break; }
2698 for (i = 0; i < opt[1]; i++)
2699 p += sprintf(CS p, "%2.2x ", opt[i]);
2708 log_write(0, LOG_MAIN, "%s", big_buffer);
2710 /* Refuse any call with IP options. This is what tcpwrappers 7.5 does. */
2712 log_write(0, LOG_MAIN|LOG_REJECT,
2713 "connection from %s refused (IP options)", host_and_ident(FALSE));
2715 smtp_printf("554 SMTP service not available\r\n", FALSE);
2719 /* Length of options = 0 => there are no options */
2721 else DEBUG(D_receive) debug_printf("no IP options found\n");
2723 #endif /* HAVE_IPV6 && !defined(NO_IP_OPTIONS) */
2725 /* Set keep-alive in socket options. The option is on by default. This
2726 setting is an attempt to get rid of some hanging connections that stick in
2727 read() when the remote end (usually a dialup) goes away. */
2729 if (smtp_accept_keepalive && !f.sender_host_notsocket)
2730 ip_keepalive(fileno(smtp_out), sender_host_address, FALSE);
2732 /* If the current host matches host_lookup, set the name by doing a
2733 reverse lookup. On failure, sender_host_name will be NULL and
2734 host_lookup_failed will be TRUE. This may or may not be serious - optional
2737 if (verify_check_host(&host_lookup) == OK)
2739 (void)host_name_lookup();
2740 host_build_sender_fullhost();
2743 /* Delay this until we have the full name, if it is looked up. */
2745 set_process_info("handling incoming connection from %s",
2746 host_and_ident(FALSE));
2748 /* Expand smtp_receive_timeout, if needed */
2750 if (smtp_receive_timeout_s)
2753 if ( !(exp = expand_string(smtp_receive_timeout_s))
2755 || (smtp_receive_timeout = readconf_readtime(exp, 0, FALSE)) < 0
2757 log_write(0, LOG_MAIN|LOG_PANIC,
2758 "bad value for smtp_receive_timeout: '%s'", exp ? exp : US"");
2761 /* Test for explicit connection rejection */
2763 if (verify_check_host(&host_reject_connection) == OK)
2765 log_write(L_connection_reject, LOG_MAIN|LOG_REJECT, "refused connection "
2766 "from %s (host_reject_connection)", host_and_ident(FALSE));
2767 smtp_printf("554 SMTP service not available\r\n", FALSE);
2771 /* Test with TCP Wrappers if so configured. There is a problem in that
2772 hosts_ctl() returns 0 (deny) under a number of system failure circumstances,
2773 such as disks dying. In these cases, it is desirable to reject with a 4xx
2774 error instead of a 5xx error. There isn't a "right" way to detect such
2775 problems. The following kludge is used: errno is zeroed before calling
2776 hosts_ctl(). If the result is "reject", a 5xx error is given only if the
2777 value of errno is 0 or ENOENT (which happens if /etc/hosts.{allow,deny} does
2780 #ifdef USE_TCP_WRAPPERS
2782 if (!(tcp_wrappers_name = expand_string(tcp_wrappers_daemon_name)))
2783 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "Expansion of \"%s\" "
2784 "(tcp_wrappers_name) failed: %s", string_printing(tcp_wrappers_name),
2785 expand_string_message);
2787 if (!hosts_ctl(tcp_wrappers_name,
2788 sender_host_name ? CS sender_host_name : STRING_UNKNOWN,
2789 sender_host_address ? CS sender_host_address : STRING_UNKNOWN,
2790 sender_ident ? CS sender_ident : STRING_UNKNOWN))
2792 if (errno == 0 || errno == ENOENT)
2794 HDEBUG(D_receive) debug_printf("tcp wrappers rejection\n");
2795 log_write(L_connection_reject,
2796 LOG_MAIN|LOG_REJECT, "refused connection from %s "
2797 "(tcp wrappers)", host_and_ident(FALSE));
2798 smtp_printf("554 SMTP service not available\r\n", FALSE);
2802 int save_errno = errno;
2803 HDEBUG(D_receive) debug_printf("tcp wrappers rejected with unexpected "
2804 "errno value %d\n", save_errno);
2805 log_write(L_connection_reject,
2806 LOG_MAIN|LOG_REJECT, "temporarily refused connection from %s "
2807 "(tcp wrappers errno=%d)", host_and_ident(FALSE), save_errno);
2808 smtp_printf("451 Temporary local problem - please try later\r\n", FALSE);
2814 /* Check for reserved slots. The value of smtp_accept_count has already been
2815 incremented to include this process. */
2817 if (smtp_accept_max > 0 &&
2818 smtp_accept_count > smtp_accept_max - smtp_accept_reserve)
2820 if ((rc = verify_check_host(&smtp_reserve_hosts)) != OK)
2822 log_write(L_connection_reject,
2823 LOG_MAIN, "temporarily refused connection from %s: not in "
2824 "reserve list: connected=%d max=%d reserve=%d%s",
2825 host_and_ident(FALSE), smtp_accept_count - 1, smtp_accept_max,
2826 smtp_accept_reserve, (rc == DEFER)? " (lookup deferred)" : "");
2827 smtp_printf("421 %s: Too many concurrent SMTP connections; "
2828 "please try again later\r\n", FALSE, smtp_active_hostname);
2831 reserved_host = TRUE;
2834 /* If a load level above which only messages from reserved hosts are
2835 accepted is set, check the load. For incoming calls via the daemon, the
2836 check is done in the superior process if there are no reserved hosts, to
2837 save a fork. In all cases, the load average will already be available
2838 in a global variable at this point. */
2840 if (smtp_load_reserve >= 0 &&
2841 load_average > smtp_load_reserve &&
2843 verify_check_host(&smtp_reserve_hosts) != OK)
2845 log_write(L_connection_reject,
2846 LOG_MAIN, "temporarily refused connection from %s: not in "
2847 "reserve list and load average = %.2f", host_and_ident(FALSE),
2848 (double)load_average/1000.0);
2849 smtp_printf("421 %s: Too much load; please try again later\r\n", FALSE,
2850 smtp_active_hostname);
2854 /* Determine whether unqualified senders or recipients are permitted
2855 for this host. Unfortunately, we have to do this every time, in order to
2856 set the flags so that they can be inspected when considering qualifying
2857 addresses in the headers. For a site that permits no qualification, this
2858 won't take long, however. */
2860 f.allow_unqualified_sender =
2861 verify_check_host(&sender_unqualified_hosts) == OK;
2863 f.allow_unqualified_recipient =
2864 verify_check_host(&recipient_unqualified_hosts) == OK;
2866 /* Determine whether HELO/EHLO is required for this host. The requirement
2867 can be hard or soft. */
2869 fl.helo_required = verify_check_host(&helo_verify_hosts) == OK;
2870 if (!fl.helo_required)
2871 fl.helo_verify = verify_check_host(&helo_try_verify_hosts) == OK;
2873 /* Determine whether this hosts is permitted to send syntactic junk
2874 after a HELO or EHLO command. */
2876 fl.helo_accept_junk = verify_check_host(&helo_accept_junk_hosts) == OK;
2879 /* For batch SMTP input we are now done. */
2881 if (smtp_batched_input) return TRUE;
2883 /* If valid Proxy Protocol source is connecting, set up session.
2884 * Failure will not allow any SMTP function other than QUIT. */
2886 #ifdef SUPPORT_PROXY
2887 proxy_session = FALSE;
2888 f.proxy_session_failed = FALSE;
2889 if (check_proxy_protocol_host())
2890 setup_proxy_protocol_host();
2893 /* Start up TLS if tls_on_connect is set. This is for supporting the legacy
2894 smtps port for use with older style SSL MTAs. */
2897 if (tls_in.on_connect)
2899 if (tls_server_start(tls_require_ciphers, &user_msg) != OK)
2900 return smtp_log_tls_fail(user_msg);
2901 cmd_list[CMD_LIST_TLS_AUTH].is_mail_cmd = TRUE;
2905 /* Run the connect ACL if it exists */
2908 if (acl_smtp_connect)
2911 if ((rc = acl_check(ACL_WHERE_CONNECT, NULL, acl_smtp_connect, &user_msg,
2914 (void) smtp_handle_acl_fail(ACL_WHERE_CONNECT, rc, user_msg, log_msg);
2919 /* Output the initial message for a two-way SMTP connection. It may contain
2920 newlines, which then cause a multi-line response to be given. */
2922 code = US"220"; /* Default status code */
2923 esc = US""; /* Default extended status code */
2924 esclen = 0; /* Length of esc */
2928 if (!(s = expand_string(smtp_banner)))
2929 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "Expansion of \"%s\" (smtp_banner) "
2930 "failed: %s", smtp_banner, expand_string_message);
2936 smtp_message_code(&code, &codelen, &s, NULL, TRUE);
2940 esclen = codelen - 4;
2944 /* Remove any terminating newlines; might as well remove trailing space too */
2947 while (p > s && isspace(p[-1])) p--;
2950 /* It seems that CC:Mail is braindead, and assumes that the greeting message
2951 is all contained in a single IP packet. The original code wrote out the
2952 greeting using several calls to fprint/fputc, and on busy servers this could
2953 cause it to be split over more than one packet - which caused CC:Mail to fall
2954 over when it got the second part of the greeting after sending its first
2955 command. Sigh. To try to avoid this, build the complete greeting message
2956 first, and output it in one fell swoop. This gives a better chance of it
2957 ending up as a single packet. */
2959 ss = string_get(256);
2962 do /* At least once, in case we have an empty string */
2965 uschar *linebreak = Ustrchr(p, '\n');
2966 ss = string_catn(ss, code, 3);
2970 ss = string_catn(ss, US" ", 1);
2974 len = linebreak - p;
2975 ss = string_catn(ss, US"-", 1);
2977 ss = string_catn(ss, esc, esclen);
2978 ss = string_catn(ss, p, len);
2979 ss = string_catn(ss, US"\r\n", 2);
2985 /* Before we write the banner, check that there is no input pending, unless
2986 this synchronisation check is disabled. */
2990 unsigned n = smtp_inend - smtp_inptr;
2993 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP protocol "
2994 "synchronization error (input sent without waiting for greeting): "
2995 "rejected connection from %s input=\"%s\"", host_and_ident(TRUE),
2996 string_printing(string_copyn(smtp_inptr, n)));
2997 smtp_printf("554 SMTP synchronization error\r\n", FALSE);
3001 /* Now output the banner */
3003 smtp_printf("%s", FALSE, string_from_gstring(ss));
3005 /* Attempt to see if we sent the banner before the last ACK of the 3-way
3006 handshake arrived. If so we must have managed a TFO. */
3019 /*************************************************
3020 * Handle SMTP syntax and protocol errors *
3021 *************************************************/
3023 /* Write to the log for SMTP syntax errors in incoming commands, if configured
3024 to do so. Then transmit the error response. The return value depends on the
3025 number of syntax and protocol errors in this SMTP session.
3028 type error type, given as a log flag bit
3029 code response code; <= 0 means don't send a response
3030 data data to reflect in the response (can be NULL)
3031 errmess the error message
3033 Returns: -1 limit of syntax/protocol errors NOT exceeded
3034 +1 limit of syntax/protocol errors IS exceeded
3036 These values fit in with the values of the "done" variable in the main
3037 processing loop in smtp_setup_msg(). */
3040 synprot_error(int type, int code, uschar *data, uschar *errmess)
3044 log_write(type, LOG_MAIN, "SMTP %s error in \"%s\" %s %s",
3045 (type == L_smtp_syntax_error)? "syntax" : "protocol",
3046 string_printing(smtp_cmd_buffer), host_and_ident(TRUE), errmess);
3048 if (++synprot_error_count > smtp_max_synprot_errors)
3051 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
3052 "syntax or protocol errors (last command was \"%s\")",
3053 host_and_ident(FALSE), string_printing(smtp_cmd_buffer));
3058 smtp_printf("%d%c%s%s%s\r\n", FALSE, code, yield == 1 ? '-' : ' ',
3059 data ? data : US"", data ? US": " : US"", errmess);
3061 smtp_printf("%d Too many syntax or protocol errors\r\n", FALSE, code);
3070 /*************************************************
3071 * Send SMTP response, possibly multiline *
3072 *************************************************/
3074 /* There are, it seems, broken clients out there that cannot handle multiline
3075 responses. If no_multiline_responses is TRUE (it can be set from an ACL), we
3076 output nothing for non-final calls, and only the first line for anything else.
3079 code SMTP code, may involve extended status codes
3080 codelen length of smtp code; if > 4 there's an ESC
3081 final FALSE if the last line isn't the final line
3082 msg message text, possibly containing newlines
3088 smtp_respond(uschar* code, int codelen, BOOL final, uschar *msg)
3093 if (!final && f.no_multiline_responses) return;
3098 esclen = codelen - 4;
3101 /* If this is the first output for a (non-batch) RCPT command, see if all RCPTs
3102 have had the same. Note: this code is also present in smtp_printf(). It would
3103 be tidier to have it only in one place, but when it was added, it was easier to
3104 do it that way, so as not to have to mess with the code for the RCPT command,
3105 which sometimes uses smtp_printf() and sometimes smtp_respond(). */
3107 if (fl.rcpt_in_progress)
3109 if (rcpt_smtp_response == NULL)
3110 rcpt_smtp_response = string_copy(msg);
3111 else if (fl.rcpt_smtp_response_same &&
3112 Ustrcmp(rcpt_smtp_response, msg) != 0)
3113 fl.rcpt_smtp_response_same = FALSE;
3114 fl.rcpt_in_progress = FALSE;
3117 /* Now output the message, splitting it up into multiple lines if necessary.
3118 We only handle pipelining these responses as far as nonfinal/final groups,
3119 not the whole MAIL/RCPT/DATA response set. */
3123 uschar *nl = Ustrchr(msg, '\n');
3126 smtp_printf("%.3s%c%.*s%s\r\n", !final, code, final ? ' ':'-', esclen, esc, msg);
3129 else if (nl[1] == 0 || f.no_multiline_responses)
3131 smtp_printf("%.3s%c%.*s%.*s\r\n", !final, code, final ? ' ':'-', esclen, esc,
3132 (int)(nl - msg), msg);
3137 smtp_printf("%.3s-%.*s%.*s\r\n", TRUE, code, esclen, esc, (int)(nl - msg), msg);
3139 while (isspace(*msg)) msg++;
3147 /*************************************************
3148 * Parse user SMTP message *
3149 *************************************************/
3151 /* This function allows for user messages overriding the response code details
3152 by providing a suitable response code string at the start of the message
3153 user_msg. Check the message for starting with a response code and optionally an
3154 extended status code. If found, check that the first digit is valid, and if so,
3155 change the code pointer and length to use the replacement. An invalid code
3156 causes a panic log; in this case, if the log messages is the same as the user
3157 message, we must also adjust the value of the log message to show the code that
3158 is actually going to be used (the original one).
3160 This function is global because it is called from receive.c as well as within
3163 Note that the code length returned includes the terminating whitespace
3164 character, which is always included in the regex match.
3167 code SMTP code, may involve extended status codes
3168 codelen length of smtp code; if > 4 there's an ESC
3170 log_msg optional log message, to be adjusted with the new SMTP code
3171 check_valid if true, verify the response code
3177 smtp_message_code(uschar **code, int *codelen, uschar **msg, uschar **log_msg,
3183 if (!msg || !*msg) return;
3185 if ((n = pcre_exec(regex_smtp_code, NULL, CS *msg, Ustrlen(*msg), 0,
3186 PCRE_EOPT, ovector, sizeof(ovector)/sizeof(int))) < 0) return;
3188 if (check_valid && (*msg)[0] != (*code)[0])
3190 log_write(0, LOG_MAIN|LOG_PANIC, "configured error code starts with "
3191 "incorrect digit (expected %c) in \"%s\"", (*code)[0], *msg);
3192 if (log_msg != NULL && *log_msg == *msg)
3193 *log_msg = string_sprintf("%s %s", *code, *log_msg + ovector[1]);
3198 *codelen = ovector[1]; /* Includes final space */
3200 *msg += ovector[1]; /* Chop the code off the message */
3207 /*************************************************
3208 * Handle an ACL failure *
3209 *************************************************/
3211 /* This function is called when acl_check() fails. As well as calls from within
3212 this module, it is called from receive.c for an ACL after DATA. It sorts out
3213 logging the incident, and sends the error response. A message containing
3214 newlines is turned into a multiline SMTP response, but for logging, only the
3217 There's a table of default permanent failure response codes to use in
3218 globals.c, along with the table of names. VFRY is special. Despite RFC1123 it
3219 defaults disabled in Exim. However, discussion in connection with RFC 821bis
3220 (aka RFC 2821) has concluded that the response should be 252 in the disabled
3221 state, because there are broken clients that try VRFY before RCPT. A 5xx
3222 response should be given only when the address is positively known to be
3223 undeliverable. Sigh. We return 252 if there is no VRFY ACL or it provides
3224 no explicit code, but if there is one we let it know best.
3225 Also, for ETRN, 458 is given on refusal, and for AUTH, 503.
3227 From Exim 4.63, it is possible to override the response code details by
3228 providing a suitable response code string at the start of the message provided
3229 in user_msg. The code's first digit is checked for validity.
3232 where where the ACL was called from
3234 user_msg a message that can be included in an SMTP response
3235 log_msg a message for logging
3237 Returns: 0 in most cases
3238 2 if the failure code was FAIL_DROP, in which case the
3239 SMTP connection should be dropped (this value fits with the
3240 "done" variable in smtp_setup_msg() below)
3244 smtp_handle_acl_fail(int where, int rc, uschar *user_msg, uschar *log_msg)
3246 BOOL drop = rc == FAIL_DROP;
3250 uschar *sender_info = US"";
3252 #ifdef WITH_CONTENT_SCAN
3253 where == ACL_WHERE_MIME ? US"during MIME ACL checks" :
3255 where == ACL_WHERE_PREDATA ? US"DATA" :
3256 where == ACL_WHERE_DATA ? US"after DATA" :
3257 #ifndef DISABLE_PRDR
3258 where == ACL_WHERE_PRDR ? US"after DATA PRDR" :
3261 string_sprintf("%s %s", acl_wherenames[where], smtp_cmd_data) :
3262 string_sprintf("%s in \"connect\" ACL", acl_wherenames[where]);
3264 if (drop) rc = FAIL;
3266 /* Set the default SMTP code, and allow a user message to change it. */
3268 smtp_code = rc == FAIL ? acl_wherecodes[where] : US"451";
3269 smtp_message_code(&smtp_code, &codelen, &user_msg, &log_msg,
3270 where != ACL_WHERE_VRFY);
3272 /* We used to have sender_address here; however, there was a bug that was not
3273 updating sender_address after a rewrite during a verify. When this bug was
3274 fixed, sender_address at this point became the rewritten address. I'm not sure
3275 this is what should be logged, so I've changed to logging the unrewritten
3276 address to retain backward compatibility. */
3278 #ifndef WITH_CONTENT_SCAN
3279 if (where == ACL_WHERE_RCPT || where == ACL_WHERE_DATA)
3281 if (where == ACL_WHERE_RCPT || where == ACL_WHERE_DATA || where == ACL_WHERE_MIME)
3284 sender_info = string_sprintf("F=<%s>%s%s%s%s ",
3285 sender_address_unrewritten ? sender_address_unrewritten : sender_address,
3286 sender_host_authenticated ? US" A=" : US"",
3287 sender_host_authenticated ? sender_host_authenticated : US"",
3288 sender_host_authenticated && authenticated_id ? US":" : US"",
3289 sender_host_authenticated && authenticated_id ? authenticated_id : US""
3293 /* If there's been a sender verification failure with a specific message, and
3294 we have not sent a response about it yet, do so now, as a preliminary line for
3295 failures, but not defers. However, always log it for defer, and log it for fail
3296 unless the sender_verify_fail log selector has been turned off. */
3298 if (sender_verified_failed &&
3299 !testflag(sender_verified_failed, af_sverify_told))
3301 BOOL save_rcpt_in_progress = fl.rcpt_in_progress;
3302 fl.rcpt_in_progress = FALSE; /* So as not to treat these as the error */
3304 setflag(sender_verified_failed, af_sverify_told);
3306 if (rc != FAIL || LOGGING(sender_verify_fail))
3307 log_write(0, LOG_MAIN|LOG_REJECT, "%s sender verify %s for <%s>%s",
3308 host_and_ident(TRUE),
3309 ((sender_verified_failed->special_action & 255) == DEFER)? "defer":"fail",
3310 sender_verified_failed->address,
3311 (sender_verified_failed->message == NULL)? US"" :
3312 string_sprintf(": %s", sender_verified_failed->message));
3314 if (rc == FAIL && sender_verified_failed->user_message)
3315 smtp_respond(smtp_code, codelen, FALSE, string_sprintf(
3316 testflag(sender_verified_failed, af_verify_pmfail)?
3317 "Postmaster verification failed while checking <%s>\n%s\n"
3318 "Several RFCs state that you are required to have a postmaster\n"
3319 "mailbox for each mail domain. This host does not accept mail\n"
3320 "from domains whose servers reject the postmaster address."
3322 testflag(sender_verified_failed, af_verify_nsfail)?
3323 "Callback setup failed while verifying <%s>\n%s\n"
3324 "The initial connection, or a HELO or MAIL FROM:<> command was\n"
3325 "rejected. Refusing MAIL FROM:<> does not help fight spam, disregards\n"
3326 "RFC requirements, and stops you from receiving standard bounce\n"
3327 "messages. This host does not accept mail from domains whose servers\n"
3330 "Verification failed for <%s>\n%s",
3331 sender_verified_failed->address,
3332 sender_verified_failed->user_message));
3334 fl.rcpt_in_progress = save_rcpt_in_progress;
3337 /* Sort out text for logging */
3339 log_msg = log_msg ? string_sprintf(": %s", log_msg) : US"";
3340 if ((lognl = Ustrchr(log_msg, '\n'))) *lognl = 0;
3342 /* Send permanent failure response to the command, but the code used isn't
3343 always a 5xx one - see comments at the start of this function. If the original
3344 rc was FAIL_DROP we drop the connection and yield 2. */
3347 smtp_respond(smtp_code, codelen, TRUE,
3348 user_msg ? user_msg : US"Administrative prohibition");
3350 /* Send temporary failure response to the command. Don't give any details,
3351 unless acl_temp_details is set. This is TRUE for a callout defer, a "defer"
3352 verb, and for a header verify when smtp_return_error_details is set.
3354 This conditional logic is all somewhat of a mess because of the odd
3355 interactions between temp_details and return_error_details. One day it should
3356 be re-implemented in a tidier fashion. */
3359 if (f.acl_temp_details && user_msg)
3361 if ( smtp_return_error_details
3362 && sender_verified_failed
3363 && sender_verified_failed->message
3365 smtp_respond(smtp_code, codelen, FALSE, sender_verified_failed->message);
3367 smtp_respond(smtp_code, codelen, TRUE, user_msg);
3370 smtp_respond(smtp_code, codelen, TRUE,
3371 US"Temporary local problem - please try later");
3373 /* Log the incident to the logs that are specified by log_reject_target
3374 (default main, reject). This can be empty to suppress logging of rejections. If
3375 the connection is not forcibly to be dropped, return 0. Otherwise, log why it
3376 is closing if required and return 2. */
3378 if (log_reject_target != 0)
3381 gstring * g = s_tlslog(NULL);
3382 uschar * tls = string_from_gstring(g);
3383 if (!tls) tls = US"";
3385 uschar * tls = US"";
3387 log_write(where == ACL_WHERE_CONNECT ? L_connection_reject : 0,
3388 log_reject_target, "%s%s%s %s%srejected %s%s",
3389 LOGGING(dnssec) && sender_host_dnssec ? US" DS" : US"",
3390 host_and_ident(TRUE),
3393 rc == FAIL ? US"" : US"temporarily ",
3397 if (!drop) return 0;
3399 log_write(L_smtp_connection, LOG_MAIN, "%s closed by DROP in ACL",
3400 smtp_get_connection_info());
3402 /* Run the not-quit ACL, but without any custom messages. This should not be a
3403 problem, because we get here only if some other ACL has issued "drop", and
3404 in that case, *its* custom messages will have been used above. */
3406 smtp_notquit_exit(US"acl-drop", NULL, NULL);
3413 /*************************************************
3414 * Handle SMTP exit when QUIT is not given *
3415 *************************************************/
3417 /* This function provides a logging/statistics hook for when an SMTP connection
3418 is dropped on the floor or the other end goes away. It's a global function
3419 because it's called from receive.c as well as this module. As well as running
3420 the NOTQUIT ACL, if there is one, this function also outputs a final SMTP
3421 response, either with a custom message from the ACL, or using a default. There
3422 is one case, however, when no message is output - after "drop". In that case,
3423 the ACL that obeyed "drop" has already supplied the custom message, and NULL is
3424 passed to this function.
3426 In case things go wrong while processing this function, causing an error that
3427 may re-enter this function, there is a recursion check.
3430 reason What $smtp_notquit_reason will be set to in the ACL;
3431 if NULL, the ACL is not run
3432 code The error code to return as part of the response
3433 defaultrespond The default message if there's no user_msg
3439 smtp_notquit_exit(uschar *reason, uschar *code, uschar *defaultrespond, ...)
3442 uschar *user_msg = NULL;
3443 uschar *log_msg = NULL;
3445 /* Check for recursive acll */
3447 if (fl.smtp_exit_function_called)
3449 log_write(0, LOG_PANIC, "smtp_notquit_exit() called more than once (%s)",
3453 fl.smtp_exit_function_called = TRUE;
3455 /* Call the not-QUIT ACL, if there is one, unless no reason is given. */
3457 if (acl_smtp_notquit && reason)
3459 smtp_notquit_reason = reason;
3460 if ((rc = acl_check(ACL_WHERE_NOTQUIT, NULL, acl_smtp_notquit, &user_msg,
3461 &log_msg)) == ERROR)
3462 log_write(0, LOG_MAIN|LOG_PANIC, "ACL for not-QUIT returned ERROR: %s",
3466 /* Write an SMTP response if we are expected to give one. As the default
3467 responses are all internal, they should always fit in the buffer, but code a
3468 warning, just in case. Note that string_vformat() still leaves a complete
3469 string, even if it is incomplete. */
3471 if (code && defaultrespond)
3474 smtp_respond(code, 3, TRUE, user_msg);
3479 va_start(ap, defaultrespond);
3480 if (!string_vformat(buffer, sizeof(buffer), CS defaultrespond, ap))
3481 log_write(0, LOG_MAIN|LOG_PANIC, "string too large in smtp_notquit_exit()");
3482 smtp_printf("%s %s\r\n", FALSE, code, buffer);
3492 /*************************************************
3493 * Verify HELO argument *
3494 *************************************************/
3496 /* This function is called if helo_verify_hosts or helo_try_verify_hosts is
3497 matched. It is also called from ACL processing if verify = helo is used and
3498 verification was not previously tried (i.e. helo_try_verify_hosts was not
3499 matched). The result of its processing is to set helo_verified and
3500 helo_verify_failed. These variables should both be FALSE for this function to
3503 Note that EHLO/HELO is legitimately allowed to quote an address literal. Allow
3504 for IPv6 ::ffff: literals.
3507 Returns: TRUE if testing was completed;
3508 FALSE on a temporary failure
3512 smtp_verify_helo(void)
3516 HDEBUG(D_receive) debug_printf("verifying EHLO/HELO argument \"%s\"\n",
3519 if (sender_helo_name == NULL)
3521 HDEBUG(D_receive) debug_printf("no EHLO/HELO command was issued\n");
3524 /* Deal with the case of -bs without an IP address */
3526 else if (sender_host_address == NULL)
3528 HDEBUG(D_receive) debug_printf("no client IP address: assume success\n");
3529 f.helo_verified = TRUE;
3532 /* Deal with the more common case when there is a sending IP address */
3534 else if (sender_helo_name[0] == '[')
3536 f.helo_verified = Ustrncmp(sender_helo_name+1, sender_host_address,
3537 Ustrlen(sender_host_address)) == 0;
3540 if (!f.helo_verified)
3542 if (strncmpic(sender_host_address, US"::ffff:", 7) == 0)
3543 f.helo_verified = Ustrncmp(sender_helo_name + 1,
3544 sender_host_address + 7, Ustrlen(sender_host_address) - 7) == 0;
3549 { if (f.helo_verified) debug_printf("matched host address\n"); }
3552 /* Do a reverse lookup if one hasn't already given a positive or negative
3553 response. If that fails, or the name doesn't match, try checking with a forward
3558 if (sender_host_name == NULL && !host_lookup_failed)
3559 yield = host_name_lookup() != DEFER;
3561 /* If a host name is known, check it and all its aliases. */
3563 if (sender_host_name)
3564 if ((f.helo_verified = strcmpic(sender_host_name, sender_helo_name) == 0))
3566 sender_helo_dnssec = sender_host_dnssec;
3567 HDEBUG(D_receive) debug_printf("matched host name\n");
3571 uschar **aliases = sender_host_aliases;
3573 if ((f.helo_verified = strcmpic(*aliases++, sender_helo_name) == 0))
3575 sender_helo_dnssec = sender_host_dnssec;
3579 HDEBUG(D_receive) if (f.helo_verified)
3580 debug_printf("matched alias %s\n", *(--aliases));
3583 /* Final attempt: try a forward lookup of the helo name */
3585 if (!f.helo_verified)
3592 h.name = sender_helo_name;
3599 HDEBUG(D_receive) debug_printf("getting IP address for %s\n",
3601 rc = host_find_bydns(&h, NULL, HOST_FIND_BY_A | HOST_FIND_BY_AAAA,
3602 NULL, NULL, NULL, &d, NULL, NULL);
3603 if (rc == HOST_FOUND || rc == HOST_FOUND_LOCAL)
3604 for (hh = &h; hh; hh = hh->next)
3605 if (Ustrcmp(hh->address, sender_host_address) == 0)
3607 f.helo_verified = TRUE;
3608 if (h.dnssec == DS_YES) sender_helo_dnssec = TRUE;
3611 debug_printf("IP address for %s matches calling address\n"
3612 "Forward DNS security status: %sverified\n",
3613 sender_helo_name, sender_helo_dnssec ? "" : "un");
3620 if (!f.helo_verified) f.helo_verify_failed = TRUE; /* We've tried ... */
3627 /*************************************************
3628 * Send user response message *
3629 *************************************************/
3631 /* This function is passed a default response code and a user message. It calls
3632 smtp_message_code() to check and possibly modify the response code, and then
3633 calls smtp_respond() to transmit the response. I put this into a function
3634 just to avoid a lot of repetition.
3637 code the response code
3638 user_msg the user message
3644 smtp_user_msg(uschar *code, uschar *user_msg)
3647 smtp_message_code(&code, &len, &user_msg, NULL, TRUE);
3648 smtp_respond(code, len, TRUE, user_msg);
3654 smtp_in_auth(auth_instance *au, uschar ** s, uschar ** ss)
3656 const uschar *set_id = NULL;
3659 /* Run the checking code, passing the remainder of the command line as
3660 data. Initials the $auth<n> variables as empty. Initialize $0 empty and set
3661 it as the only set numerical variable. The authenticator may set $auth<n>
3662 and also set other numeric variables. The $auth<n> variables are preferred
3663 nowadays; the numerical variables remain for backwards compatibility.
3665 Afterwards, have a go at expanding the set_id string, even if
3666 authentication failed - for bad passwords it can be useful to log the
3667 userid. On success, require set_id to expand and exist, and put it in
3668 authenticated_id. Save this in permanent store, as the working store gets
3669 reset at HELO, RSET, etc. */
3671 for (i = 0; i < AUTH_VARS; i++) auth_vars[i] = NULL;
3673 expand_nlength[0] = 0; /* $0 contains nothing */
3675 rc = (au->info->servercode)(au, smtp_cmd_data);
3676 if (au->set_id) set_id = expand_string(au->set_id);
3677 expand_nmax = -1; /* Reset numeric variables */
3678 for (i = 0; i < AUTH_VARS; i++) auth_vars[i] = NULL; /* Reset $auth<n> */
3680 /* The value of authenticated_id is stored in the spool file and printed in
3681 log lines. It must not contain binary zeros or newline characters. In
3682 normal use, it never will, but when playing around or testing, this error
3683 can (did) happen. To guard against this, ensure that the id contains only
3684 printing characters. */
3686 if (set_id) set_id = string_printing(set_id);
3688 /* For the non-OK cases, set up additional logging data if set_id
3692 set_id = set_id && *set_id
3693 ? string_sprintf(" (set_id=%s)", set_id) : US"";
3695 /* Switch on the result */
3700 if (!au->set_id || set_id) /* Complete success */
3702 if (set_id) authenticated_id = string_copy_malloc(set_id);
3703 sender_host_authenticated = au->name;
3704 sender_host_auth_pubname = au->public_name;
3705 authentication_failed = FALSE;
3706 authenticated_fail_id = NULL; /* Impossible to already be set? */
3709 (sender_host_address ? protocols : protocols_local)
3710 [pextend + pauthed + (tls_in.active.sock >= 0 ? pcrpted:0)];
3711 *s = *ss = US"235 Authentication succeeded";
3712 authenticated_by = au;
3716 /* Authentication succeeded, but we failed to expand the set_id string.
3717 Treat this as a temporary error. */
3719 auth_defer_msg = expand_string_message;
3723 if (set_id) authenticated_fail_id = string_copy_malloc(set_id);
3724 *s = string_sprintf("435 Unable to authenticate at present%s",
3725 auth_defer_user_msg);
3726 *ss = string_sprintf("435 Unable to authenticate at present%s: %s",
3727 set_id, auth_defer_msg);
3731 *s = *ss = US"501 Invalid base64 data";
3735 *s = *ss = US"501 Authentication cancelled";
3739 *s = *ss = US"553 Initial data not expected";
3743 if (set_id) authenticated_fail_id = string_copy_malloc(set_id);
3744 *s = US"535 Incorrect authentication data";
3745 *ss = string_sprintf("535 Incorrect authentication data%s", set_id);
3749 if (set_id) authenticated_fail_id = string_copy_malloc(set_id);
3750 *s = US"435 Internal error";
3751 *ss = string_sprintf("435 Internal error%s: return %d from authentication "
3752 "check", set_id, rc);
3764 qualify_recipient(uschar ** recipient, uschar * smtp_cmd_data, uschar * tag)
3767 if (f.allow_unqualified_recipient || strcmpic(*recipient, US"postmaster") == 0)
3769 DEBUG(D_receive) debug_printf("unqualified address %s accepted\n",
3771 rd = Ustrlen(recipient) + 1;
3772 *recipient = rewrite_address_qualify(*recipient, TRUE);
3775 smtp_printf("501 %s: recipient address must contain a domain\r\n", FALSE,
3777 log_write(L_smtp_syntax_error,
3778 LOG_MAIN|LOG_REJECT, "unqualified %s rejected: <%s> %s%s",
3779 tag, *recipient, host_and_ident(TRUE), host_lookup_msg);
3787 smtp_quit_handler(uschar ** user_msgp, uschar ** log_msgp)
3790 incomplete_transaction_log(US"QUIT");
3793 int rc = acl_check(ACL_WHERE_QUIT, NULL, acl_smtp_quit, user_msgp, log_msgp);
3795 log_write(0, LOG_MAIN|LOG_PANIC, "ACL for QUIT returned ERROR: %s",
3799 smtp_respond(US"221", 3, TRUE, *user_msgp);
3801 smtp_printf("221 %s closing connection\r\n", FALSE, smtp_active_hostname);
3804 tls_close(NULL, TLS_SHUTDOWN_NOWAIT);
3807 log_write(L_smtp_connection, LOG_MAIN, "%s closed by QUIT",
3808 smtp_get_connection_info());
3813 smtp_rset_handler(void)
3816 incomplete_transaction_log(US"RSET");
3817 smtp_printf("250 Reset OK\r\n", FALSE);
3818 cmd_list[CMD_LIST_RSET].is_mail_cmd = FALSE;
3823 /*************************************************
3824 * Initialize for SMTP incoming message *
3825 *************************************************/
3827 /* This function conducts the initial dialogue at the start of an incoming SMTP
3828 message, and builds a list of recipients. However, if the incoming message
3829 is part of a batch (-bS option) a separate function is called since it would
3830 be messy having tests splattered about all over this function. This function
3831 therefore handles the case where interaction is occurring. The input and output
3832 files are set up in smtp_in and smtp_out.
3834 The global recipients_list is set to point to a vector of recipient_item
3835 blocks, whose number is given by recipients_count. This is extended by the
3836 receive_add_recipient() function. The global variable sender_address is set to
3837 the sender's address. The yield is +1 if a message has been successfully
3838 started, 0 if a QUIT command was encountered or the connection was refused from
3839 the particular host, or -1 if the connection was lost.
3843 Returns: > 0 message successfully started (reached DATA)
3844 = 0 QUIT read or end of file reached or call refused
3849 smtp_setup_msg(void)
3852 BOOL toomany = FALSE;
3853 BOOL discarded = FALSE;
3854 BOOL last_was_rej_mail = FALSE;
3855 BOOL last_was_rcpt = FALSE;
3856 void *reset_point = store_get(0);
3858 DEBUG(D_receive) debug_printf("smtp_setup_msg entered\n");
3860 /* Reset for start of new message. We allow one RSET not to be counted as a
3861 nonmail command, for those MTAs that insist on sending it between every
3862 message. Ditto for EHLO/HELO and for STARTTLS, to allow for going in and out of
3863 TLS between messages (an Exim client may do this if it has messages queued up
3864 for the host). Note: we do NOT reset AUTH at this point. */
3866 smtp_reset(reset_point);
3867 message_ended = END_NOTSTARTED;
3869 chunking_state = f.chunking_offered ? CHUNKING_OFFERED : CHUNKING_NOT_OFFERED;
3871 cmd_list[CMD_LIST_RSET].is_mail_cmd = TRUE;
3872 cmd_list[CMD_LIST_HELO].is_mail_cmd = TRUE;
3873 cmd_list[CMD_LIST_EHLO].is_mail_cmd = TRUE;
3875 cmd_list[CMD_LIST_STARTTLS].is_mail_cmd = TRUE;
3878 /* Set the local signal handler for SIGTERM - it tries to end off tidily */
3880 had_command_sigterm = 0;
3881 os_non_restarting_signal(SIGTERM, command_sigterm_handler);
3883 /* Batched SMTP is handled in a different function. */
3885 if (smtp_batched_input) return smtp_setup_batch_msg();
3887 /* Deal with SMTP commands. This loop is exited by setting done to a POSITIVE
3888 value. The values are 2 larger than the required yield of the function. */
3892 const uschar **argv;
3893 uschar *etrn_command;
3894 uschar *etrn_serialize_key;
3896 uschar *log_msg, *smtp_code;
3897 uschar *user_msg = NULL;
3898 uschar *recipient = NULL;
3899 uschar *hello = NULL;
3901 BOOL was_rej_mail = FALSE;
3902 BOOL was_rcpt = FALSE;
3903 void (*oldsignal)(int);
3905 int start, end, sender_domain, recipient_domain;
3909 uschar *orcpt = NULL;
3914 /* Check once per STARTTLS or SSL-on-connect for a TLS AUTH */
3915 if ( tls_in.active.sock >= 0
3917 && tls_in.certificate_verified
3918 && cmd_list[CMD_LIST_TLS_AUTH].is_mail_cmd
3921 cmd_list[CMD_LIST_TLS_AUTH].is_mail_cmd = FALSE;
3923 for (au = auths; au; au = au->next)
3924 if (strcmpic(US"tls", au->driver_name) == 0)
3927 && (rc = acl_check(ACL_WHERE_AUTH, NULL, acl_smtp_auth,
3928 &user_msg, &log_msg)) != OK
3930 done = smtp_handle_acl_fail(ACL_WHERE_AUTH, rc, user_msg, log_msg);
3933 smtp_cmd_data = NULL;
3935 if (smtp_in_auth(au, &s, &ss) == OK)
3936 { DEBUG(D_auth) debug_printf("tls auth succeeded\n"); }
3938 { DEBUG(D_auth) debug_printf("tls auth not succeeded\n"); }
3946 if (smtp_in) /* Avoid pure-ACKs while in cmd pingpong phase */
3947 (void) setsockopt(fileno(smtp_in), IPPROTO_TCP, TCP_QUICKACK,
3948 US &off, sizeof(off));
3951 switch(smtp_read_command(TRUE, GETC_BUFFER_UNLIMITED))
3953 /* The AUTH command is not permitted to occur inside a transaction, and may
3954 occur successfully only once per connection. Actually, that isn't quite
3955 true. When TLS is started, all previous information about a connection must
3956 be discarded, so a new AUTH is permitted at that time.
3958 AUTH may only be used when it has been advertised. However, it seems that
3959 there are clients that send AUTH when it hasn't been advertised, some of
3960 them even doing this after HELO. And there are MTAs that accept this. Sigh.
3961 So there's a get-out that allows this to happen.
3963 AUTH is initially labelled as a "nonmail command" so that one occurrence
3964 doesn't get counted. We change the label here so that multiple failing
3965 AUTHS will eventually hit the nonmail threshold. */
3969 authentication_failed = TRUE;
3970 cmd_list[CMD_LIST_AUTH].is_mail_cmd = FALSE;
3972 if (!fl.auth_advertised && !f.allow_auth_unadvertised)
3974 done = synprot_error(L_smtp_protocol_error, 503, NULL,
3975 US"AUTH command used when not advertised");
3978 if (sender_host_authenticated)
3980 done = synprot_error(L_smtp_protocol_error, 503, NULL,
3981 US"already authenticated");
3986 done = synprot_error(L_smtp_protocol_error, 503, NULL,
3987 US"not permitted in mail transaction");
3994 && (rc = acl_check(ACL_WHERE_AUTH, NULL, acl_smtp_auth,
3995 &user_msg, &log_msg)) != OK
3998 done = smtp_handle_acl_fail(ACL_WHERE_AUTH, rc, user_msg, log_msg);
4002 /* Find the name of the requested authentication mechanism. */
4005 while ((c = *smtp_cmd_data) != 0 && !isspace(c))
4007 if (!isalnum(c) && c != '-' && c != '_')
4009 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4010 US"invalid character in authentication mechanism name");
4016 /* If not at the end of the line, we must be at white space. Terminate the
4017 name and move the pointer on to any data that may be present. */
4019 if (*smtp_cmd_data != 0)
4021 *smtp_cmd_data++ = 0;
4022 while (isspace(*smtp_cmd_data)) smtp_cmd_data++;
4025 /* Search for an authentication mechanism which is configured for use
4026 as a server and which has been advertised (unless, sigh, allow_auth_
4027 unadvertised is set). */
4029 for (au = auths; au; au = au->next)
4030 if (strcmpic(s, au->public_name) == 0 && au->server &&
4031 (au->advertised || f.allow_auth_unadvertised))
4036 c = smtp_in_auth(au, &s, &ss);
4038 smtp_printf("%s\r\n", FALSE, s);
4040 log_write(0, LOG_MAIN|LOG_REJECT, "%s authenticator failed for %s: %s",
4041 au->name, host_and_ident(FALSE), ss);
4044 done = synprot_error(L_smtp_protocol_error, 504, NULL,
4045 string_sprintf("%s authentication mechanism not supported", s));
4047 break; /* AUTH_CMD */
4049 /* The HELO/EHLO commands are permitted to appear in the middle of a
4050 session as well as at the beginning. They have the effect of a reset in
4051 addition to their other functions. Their absence at the start cannot be
4052 taken to be an error.
4056 If the EHLO command is not acceptable to the SMTP server, 501, 500,
4057 or 502 failure replies MUST be returned as appropriate. The SMTP
4058 server MUST stay in the same state after transmitting these replies
4059 that it was in before the EHLO was received.
4061 Therefore, we do not do the reset until after checking the command for
4062 acceptability. This change was made for Exim release 4.11. Previously
4063 it did the reset first. */
4076 HELO_EHLO: /* Common code for HELO and EHLO */
4077 cmd_list[CMD_LIST_HELO].is_mail_cmd = FALSE;
4078 cmd_list[CMD_LIST_EHLO].is_mail_cmd = FALSE;
4080 /* Reject the HELO if its argument was invalid or non-existent. A
4081 successful check causes the argument to be saved in malloc store. */
4083 if (!check_helo(smtp_cmd_data))
4085 smtp_printf("501 Syntactically invalid %s argument(s)\r\n", FALSE, hello);
4087 log_write(0, LOG_MAIN|LOG_REJECT, "rejected %s from %s: syntactically "
4088 "invalid argument(s): %s", hello, host_and_ident(FALSE),
4089 *smtp_cmd_argument == 0 ? US"(no argument given)" :
4090 string_printing(smtp_cmd_argument));
4092 if (++synprot_error_count > smtp_max_synprot_errors)
4094 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
4095 "syntax or protocol errors (last command was \"%s\")",
4096 host_and_ident(FALSE), string_printing(smtp_cmd_buffer));
4103 /* If sender_host_unknown is true, we have got here via the -bs interface,
4104 not called from inetd. Otherwise, we are running an IP connection and the
4105 host address will be set. If the helo name is the primary name of this
4106 host and we haven't done a reverse lookup, force one now. If helo_required
4107 is set, ensure that the HELO name matches the actual host. If helo_verify
4108 is set, do the same check, but softly. */
4110 if (!f.sender_host_unknown)
4112 BOOL old_helo_verified = f.helo_verified;
4113 uschar *p = smtp_cmd_data;
4115 while (*p != 0 && !isspace(*p)) { *p = tolower(*p); p++; }
4118 /* Force a reverse lookup if HELO quoted something in helo_lookup_domains
4119 because otherwise the log can be confusing. */
4121 if ( !sender_host_name
4122 && (deliver_domain = sender_helo_name, /* set $domain */
4123 match_isinlist(sender_helo_name, CUSS &helo_lookup_domains, 0,
4124 &domainlist_anchor, NULL, MCL_DOMAIN, TRUE, NULL)) == OK)
4125 (void)host_name_lookup();
4127 /* Rebuild the fullhost info to include the HELO name (and the real name
4128 if it was looked up.) */
4130 host_build_sender_fullhost(); /* Rebuild */
4131 set_process_info("handling%s incoming connection from %s",
4132 tls_in.active.sock >= 0 ? " TLS" : "", host_and_ident(FALSE));
4134 /* Verify if configured. This doesn't give much security, but it does
4135 make some people happy to be able to do it. If helo_required is set,
4136 (host matches helo_verify_hosts) failure forces rejection. If helo_verify
4137 is set (host matches helo_try_verify_hosts), it does not. This is perhaps
4138 now obsolescent, since the verification can now be requested selectively
4141 f.helo_verified = f.helo_verify_failed = sender_helo_dnssec = FALSE;
4142 if (fl.helo_required || fl.helo_verify)
4144 BOOL tempfail = !smtp_verify_helo();
4145 if (!f.helo_verified)
4147 if (fl.helo_required)
4149 smtp_printf("%d %s argument does not match calling host\r\n", FALSE,
4150 tempfail? 451 : 550, hello);
4151 log_write(0, LOG_MAIN|LOG_REJECT, "%srejected \"%s %s\" from %s",
4152 tempfail? "temporarily " : "",
4153 hello, sender_helo_name, host_and_ident(FALSE));
4154 f.helo_verified = old_helo_verified;
4155 break; /* End of HELO/EHLO processing */
4157 HDEBUG(D_all) debug_printf("%s verification failed but host is in "
4158 "helo_try_verify_hosts\n", hello);
4164 /* set up SPF context */
4165 spf_init(sender_helo_name, sender_host_address);
4168 /* Apply an ACL check if one is defined; afterwards, recheck
4169 synchronization in case the client started sending in a delay. */
4172 if ((rc = acl_check(ACL_WHERE_HELO, NULL, acl_smtp_helo,
4173 &user_msg, &log_msg)) != OK)
4175 done = smtp_handle_acl_fail(ACL_WHERE_HELO, rc, user_msg, log_msg);
4176 if (sender_helo_name)
4178 store_free(sender_helo_name);
4179 sender_helo_name = NULL;
4181 host_build_sender_fullhost(); /* Rebuild */
4184 else if (!check_sync()) goto SYNC_FAILURE;
4186 /* Generate an OK reply. The default string includes the ident if present,
4187 and also the IP address if present. Reflecting back the ident is intended
4188 as a deterrent to mail forgers. For maximum efficiency, and also because
4189 some broken systems expect each response to be in a single packet, arrange
4190 that the entire reply is sent in one write(). */
4192 fl.auth_advertised = FALSE;
4193 f.smtp_in_pipelining_advertised = FALSE;
4195 fl.tls_advertised = FALSE;
4196 # ifdef EXPERIMENTAL_REQUIRETLS
4197 fl.requiretls_advertised = FALSE;
4200 fl.dsn_advertised = FALSE;
4202 fl.smtputf8_advertised = FALSE;
4205 smtp_code = US"250 "; /* Default response code plus space*/
4208 s = string_sprintf("%.3s %s Hello %s%s%s",
4210 smtp_active_hostname,
4211 sender_ident ? sender_ident : US"",
4212 sender_ident ? US" at " : US"",
4213 sender_host_name ? sender_host_name : sender_helo_name);
4214 g = string_cat(NULL, s);
4216 if (sender_host_address)
4218 g = string_catn(g, US" [", 2);
4219 g = string_cat (g, sender_host_address);
4220 g = string_catn(g, US"]", 1);
4224 /* A user-supplied EHLO greeting may not contain more than one line. Note
4225 that the code returned by smtp_message_code() includes the terminating
4226 whitespace character. */
4232 smtp_message_code(&smtp_code, &codelen, &user_msg, NULL, TRUE);
4233 s = string_sprintf("%.*s%s", codelen, smtp_code, user_msg);
4234 if ((ss = strpbrk(CS s, "\r\n")) != NULL)
4236 log_write(0, LOG_MAIN|LOG_PANIC, "EHLO/HELO response must not contain "
4237 "newlines: message truncated: %s", string_printing(s));
4240 g = string_cat(NULL, s);
4243 g = string_catn(g, US"\r\n", 2);
4245 /* If we received EHLO, we must create a multiline response which includes
4246 the functions supported. */
4252 /* I'm not entirely happy with this, as an MTA is supposed to check
4253 that it has enough room to accept a message of maximum size before
4254 it sends this. However, there seems little point in not sending it.
4255 The actual size check happens later at MAIL FROM time. By postponing it
4256 till then, VRFY and EXPN can be used after EHLO when space is short. */
4258 if (thismessage_size_limit > 0)
4260 sprintf(CS big_buffer, "%.3s-SIZE %d\r\n", smtp_code,
4261 thismessage_size_limit);
4262 g = string_cat(g, big_buffer);
4266 g = string_catn(g, smtp_code, 3);
4267 g = string_catn(g, US"-SIZE\r\n", 7);
4270 /* Exim does not do protocol conversion or data conversion. It is 8-bit
4271 clean; if it has an 8-bit character in its hand, it just sends it. It
4272 cannot therefore specify 8BITMIME and remain consistent with the RFCs.
4273 However, some users want this option simply in order to stop MUAs
4274 mangling messages that contain top-bit-set characters. It is therefore
4275 provided as an option. */
4277 if (accept_8bitmime)
4279 g = string_catn(g, smtp_code, 3);
4280 g = string_catn(g, US"-8BITMIME\r\n", 11);
4283 /* Advertise DSN support if configured to do so. */
4284 if (verify_check_host(&dsn_advertise_hosts) != FAIL)
4286 g = string_catn(g, smtp_code, 3);
4287 g = string_catn(g, US"-DSN\r\n", 6);
4288 fl.dsn_advertised = TRUE;
4291 /* Advertise ETRN/VRFY/EXPN if there's are ACL checking whether a host is
4292 permitted to issue them; a check is made when any host actually tries. */
4296 g = string_catn(g, smtp_code, 3);
4297 g = string_catn(g, US"-ETRN\r\n", 7);
4301 g = string_catn(g, smtp_code, 3);
4302 g = string_catn(g, US"-VRFY\r\n", 7);
4306 g = string_catn(g, smtp_code, 3);
4307 g = string_catn(g, US"-EXPN\r\n", 7);
4310 /* Exim is quite happy with pipelining, so let the other end know that
4311 it is safe to use it, unless advertising is disabled. */
4313 if (f.pipelining_enable &&
4314 verify_check_host(&pipelining_advertise_hosts) == OK)
4316 g = string_catn(g, smtp_code, 3);
4317 g = string_catn(g, US"-PIPELINING\r\n", 13);
4318 sync_cmd_limit = NON_SYNC_CMD_PIPELINING;
4319 f.smtp_in_pipelining_advertised = TRUE;
4323 /* If any server authentication mechanisms are configured, advertise
4324 them if the current host is in auth_advertise_hosts. The problem with
4325 advertising always is that some clients then require users to
4326 authenticate (and aren't configurable otherwise) even though it may not
4327 be necessary (e.g. if the host is in host_accept_relay).
4329 RFC 2222 states that SASL mechanism names contain only upper case
4330 letters, so output the names in upper case, though we actually recognize
4331 them in either case in the AUTH command. */
4335 && !sender_host_authenticated
4337 && verify_check_host(&auth_advertise_hosts) == OK
4342 for (au = auths; au; au = au->next)
4344 au->advertised = FALSE;
4347 DEBUG(D_auth+D_expand) debug_printf_indent(
4348 "Evaluating advertise_condition for %s athenticator\n",
4350 if ( !au->advertise_condition
4351 || expand_check_condition(au->advertise_condition, au->name,
4358 g = string_catn(g, smtp_code, 3);
4359 g = string_catn(g, US"-AUTH", 5);
4361 fl.auth_advertised = TRUE;
4364 g = string_catn(g, US" ", 1);
4365 g = string_cat (g, au->public_name);
4366 while (++saveptr < g->ptr) g->s[saveptr] = toupper(g->s[saveptr]);
4367 au->advertised = TRUE;
4372 if (!first) g = string_catn(g, US"\r\n", 2);
4375 /* RFC 3030 CHUNKING */
4377 if (verify_check_host(&chunking_advertise_hosts) != FAIL)
4379 g = string_catn(g, smtp_code, 3);
4380 g = string_catn(g, US"-CHUNKING\r\n", 11);
4381 f.chunking_offered = TRUE;
4382 chunking_state = CHUNKING_OFFERED;
4385 /* Advertise TLS (Transport Level Security) aka SSL (Secure Socket Layer)
4386 if it has been included in the binary, and the host matches
4387 tls_advertise_hosts. We must *not* advertise if we are already in a
4388 secure connection. */
4391 if (tls_in.active.sock < 0 &&
4392 verify_check_host(&tls_advertise_hosts) != FAIL)
4394 g = string_catn(g, smtp_code, 3);
4395 g = string_catn(g, US"-STARTTLS\r\n", 11);
4396 fl.tls_advertised = TRUE;
4399 # ifdef EXPERIMENTAL_REQUIRETLS
4400 /* Advertise REQUIRETLS only once we are in a secure connection */
4401 if ( tls_in.active.sock >= 0
4402 && verify_check_host(&tls_advertise_requiretls) != FAIL)
4404 g = string_catn(g, smtp_code, 3);
4405 g = string_catn(g, US"-REQUIRETLS\r\n", 13);
4406 fl.requiretls_advertised = TRUE;
4411 #ifndef DISABLE_PRDR
4412 /* Per Recipient Data Response, draft by Eric A. Hall extending RFC */
4415 g = string_catn(g, smtp_code, 3);
4416 g = string_catn(g, US"-PRDR\r\n", 7);
4421 if ( accept_8bitmime
4422 && verify_check_host(&smtputf8_advertise_hosts) != FAIL)
4424 g = string_catn(g, smtp_code, 3);
4425 g = string_catn(g, US"-SMTPUTF8\r\n", 11);
4426 fl.smtputf8_advertised = TRUE;
4430 /* Finish off the multiline reply with one that is always available. */
4432 g = string_catn(g, smtp_code, 3);
4433 g = string_catn(g, US" HELP\r\n", 7);
4436 /* Terminate the string (for debug), write it, and note that HELO/EHLO
4440 if (tls_in.active.sock >= 0) (void)tls_write(NULL, g->s, g->ptr, FALSE); else
4444 int i = fwrite(g->s, 1, g->ptr, smtp_out); i = i; /* compiler quietening */
4450 (void) string_from_gstring(g);
4451 while ((cr = Ustrchr(g->s, '\r')) != NULL) /* lose CRs */
4452 memmove(cr, cr + 1, (g->ptr--) - (cr - g->s));
4453 debug_printf("SMTP>> %s", g->s);
4455 fl.helo_seen = TRUE;
4457 /* Reset the protocol and the state, abandoning any previous message. */
4459 (sender_host_address ? protocols : protocols_local)
4461 ? pextend + (sender_host_authenticated ? pauthed : 0)
4463 + (tls_in.active.sock >= 0 ? pcrpted : 0)
4465 cancel_cutthrough_connection(TRUE, US"sent EHLO response");
4466 smtp_reset(reset_point);
4468 break; /* HELO/EHLO */
4471 /* The MAIL command requires an address as an operand. All we do
4472 here is to parse it for syntactic correctness. The form "<>" is
4473 a special case which converts into an empty string. The start/end
4474 pointers in the original are not used further for this address, as
4475 it is the canonical extracted address which is all that is kept. */
4479 smtp_mailcmd_count++; /* Count for limit and ratelimit */
4480 was_rej_mail = TRUE; /* Reset if accepted */
4481 env_mail_type_t * mail_args; /* Sanity check & validate args */
4483 if (fl.helo_required && !fl.helo_seen)
4485 smtp_printf("503 HELO or EHLO required\r\n", FALSE);
4486 log_write(0, LOG_MAIN|LOG_REJECT, "rejected MAIL from %s: no "
4487 "HELO/EHLO given", host_and_ident(FALSE));
4493 done = synprot_error(L_smtp_protocol_error, 503, NULL,
4494 US"sender already given");
4498 if (!*smtp_cmd_data)
4500 done = synprot_error(L_smtp_protocol_error, 501, NULL,
4501 US"MAIL must have an address operand");
4505 /* Check to see if the limit for messages per connection would be
4506 exceeded by accepting further messages. */
4508 if (smtp_accept_max_per_connection > 0 &&
4509 smtp_mailcmd_count > smtp_accept_max_per_connection)
4511 smtp_printf("421 too many messages in this connection\r\n", FALSE);
4512 log_write(0, LOG_MAIN|LOG_REJECT, "rejected MAIL command %s: too many "
4513 "messages in one connection", host_and_ident(TRUE));
4517 /* Reset for start of message - even if this is going to fail, we
4518 obviously need to throw away any previous data. */
4520 cancel_cutthrough_connection(TRUE, US"MAIL received");
4521 smtp_reset(reset_point);
4523 sender_data = recipient_data = NULL;
4525 /* Loop, checking for ESMTP additions to the MAIL FROM command. */
4527 if (fl.esmtp) for(;;)
4529 uschar *name, *value, *end;
4530 unsigned long int size;
4531 BOOL arg_error = FALSE;
4533 if (!extract_option(&name, &value)) break;
4535 for (mail_args = env_mail_type_list;
4536 mail_args->value != ENV_MAIL_OPT_NULL;
4539 if (strcmpic(name, mail_args->name) == 0)
4541 if (mail_args->need_value && strcmpic(value, US"") == 0)
4544 switch(mail_args->value)
4546 /* Handle SIZE= by reading the value. We don't do the check till later,
4547 in order to be able to log the sender address on failure. */
4548 case ENV_MAIL_OPT_SIZE:
4549 if (((size = Ustrtoul(value, &end, 10)), *end == 0))
4551 if ((size == ULONG_MAX && errno == ERANGE) || size > INT_MAX)
4553 message_size = (int)size;
4559 /* If this session was initiated with EHLO and accept_8bitmime is set,
4560 Exim will have indicated that it supports the BODY=8BITMIME option. In
4561 fact, it does not support this according to the RFCs, in that it does not
4562 take any special action for forwarding messages containing 8-bit
4563 characters. That is why accept_8bitmime is not the default setting, but
4564 some sites want the action that is provided. We recognize both "8BITMIME"
4565 and "7BIT" as body types, but take no action. */
4566 case ENV_MAIL_OPT_BODY:
4567 if (accept_8bitmime) {
4568 if (strcmpic(value, US"8BITMIME") == 0)
4570 else if (strcmpic(value, US"7BIT") == 0)
4575 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4576 US"invalid data for BODY");
4579 DEBUG(D_receive) debug_printf("8BITMIME: %d\n", body_8bitmime);
4585 /* Handle the two DSN options, but only if configured to do so (which
4586 will have caused "DSN" to be given in the EHLO response). The code itself
4587 is included only if configured in at build time. */
4589 case ENV_MAIL_OPT_RET:
4590 if (fl.dsn_advertised)
4592 /* Check if RET has already been set */
4595 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4596 US"RET can be specified once only");
4599 dsn_ret = strcmpic(value, US"HDRS") == 0
4601 : strcmpic(value, US"FULL") == 0
4604 DEBUG(D_receive) debug_printf("DSN_RET: %d\n", dsn_ret);
4605 /* Check for invalid invalid value, and exit with error */
4608 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4609 US"Value for RET is invalid");
4614 case ENV_MAIL_OPT_ENVID:
4615 if (fl.dsn_advertised)
4617 /* Check if the dsn envid has been already set */
4620 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4621 US"ENVID can be specified once only");
4624 dsn_envid = string_copy(value);
4625 DEBUG(D_receive) debug_printf("DSN_ENVID: %s\n", dsn_envid);
4629 /* Handle the AUTH extension. If the value given is not "<>" and either
4630 the ACL says "yes" or there is no ACL but the sending host is
4631 authenticated, we set it up as the authenticated sender. However, if the
4632 authenticator set a condition to be tested, we ignore AUTH on MAIL unless
4633 the condition is met. The value of AUTH is an xtext, which means that +,
4634 = and cntrl chars are coded in hex; however "<>" is unaffected by this
4636 case ENV_MAIL_OPT_AUTH:
4637 if (Ustrcmp(value, "<>") != 0)
4642 if (auth_xtextdecode(value, &authenticated_sender) < 0)
4644 /* Put back terminator overrides for error message */
4647 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4648 US"invalid data for AUTH");
4651 if (!acl_smtp_mailauth)
4653 ignore_msg = US"client not authenticated";
4654 rc = sender_host_authenticated ? OK : FAIL;
4658 ignore_msg = US"rejected by ACL";
4659 rc = acl_check(ACL_WHERE_MAILAUTH, NULL, acl_smtp_mailauth,
4660 &user_msg, &log_msg);
4666 if (authenticated_by == NULL ||
4667 authenticated_by->mail_auth_condition == NULL ||
4668 expand_check_condition(authenticated_by->mail_auth_condition,
4669 authenticated_by->name, US"authenticator"))
4670 break; /* Accept the AUTH */
4672 ignore_msg = US"server_mail_auth_condition failed";
4673 if (authenticated_id != NULL)
4674 ignore_msg = string_sprintf("%s: authenticated ID=\"%s\"",
4675 ignore_msg, authenticated_id);
4680 authenticated_sender = NULL;
4681 log_write(0, LOG_MAIN, "ignoring AUTH=%s from %s (%s)",
4682 value, host_and_ident(TRUE), ignore_msg);
4685 /* Should only get DEFER or ERROR here. Put back terminator
4686 overrides for error message */
4691 (void)smtp_handle_acl_fail(ACL_WHERE_MAILAUTH, rc, user_msg,
4698 #ifndef DISABLE_PRDR
4699 case ENV_MAIL_OPT_PRDR:
4701 prdr_requested = TRUE;
4706 case ENV_MAIL_OPT_UTF8:
4707 if (!fl.smtputf8_advertised)
4709 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4710 US"SMTPUTF8 used when not advertised");
4714 DEBUG(D_receive) debug_printf("smtputf8 requested\n");
4715 message_smtputf8 = allow_utf8_domains = TRUE;
4716 if (Ustrncmp(received_protocol, US"utf8", 4) != 0)
4718 int old_pool = store_pool;
4719 store_pool = POOL_PERM;
4720 received_protocol = string_sprintf("utf8%s", received_protocol);
4721 store_pool = old_pool;
4726 #if defined(SUPPORT_TLS) && defined(EXPERIMENTAL_REQUIRETLS)
4727 case ENV_MAIL_OPT_REQTLS:
4731 if (!fl.requiretls_advertised)
4733 done = synprot_error(L_smtp_syntax_error, 555, NULL,
4734 US"unadvertised MAIL option: REQUIRETLS");
4738 DEBUG(D_receive) debug_printf("requiretls requested\n");
4739 tls_requiretls = REQUIRETLS_MSG;
4741 r = string_copy_malloc(received_protocol);
4742 if ((t = Ustrrchr(r, 's'))) *t = 'S';
4743 received_protocol = r;
4748 /* No valid option. Stick back the terminator characters and break
4749 the loop. Do the name-terminator second as extract_option sets
4750 value==name when it found no equal-sign.
4751 An error for a malformed address will occur. */
4752 case ENV_MAIL_OPT_NULL:
4760 /* Break out of for loop if switch() had bad argument or
4761 when start of the email address is reached */
4762 if (arg_error) break;
4765 #if defined(SUPPORT_TLS) && defined(EXPERIMENTAL_REQUIRETLS)
4766 if (tls_requiretls & REQUIRETLS_MSG)
4768 /* Ensure headers-only bounces whether a RET option was given or not. */
4770 DEBUG(D_receive) if (dsn_ret == dsn_ret_full)
4771 debug_printf("requiretls override: dsn_ret_full -> dsn_ret_hdrs\n");
4772 dsn_ret = dsn_ret_hdrs;
4776 /* If we have passed the threshold for rate limiting, apply the current
4777 delay, and update it for next time, provided this is a limited host. */
4779 if (smtp_mailcmd_count > smtp_rlm_threshold &&
4780 verify_check_host(&smtp_ratelimit_hosts) == OK)
4782 DEBUG(D_receive) debug_printf("rate limit MAIL: delay %.3g sec\n",
4783 smtp_delay_mail/1000.0);
4784 millisleep((int)smtp_delay_mail);
4785 smtp_delay_mail *= smtp_rlm_factor;
4786 if (smtp_delay_mail > (double)smtp_rlm_limit)
4787 smtp_delay_mail = (double)smtp_rlm_limit;
4790 /* Now extract the address, first applying any SMTP-time rewriting. The
4791 TRUE flag allows "<>" as a sender address. */
4793 raw_sender = rewrite_existflags & rewrite_smtp
4794 ? rewrite_one(smtp_cmd_data, rewrite_smtp, NULL, FALSE, US"",
4795 global_rewrite_rules)
4799 parse_extract_address(raw_sender, &errmess, &start, &end, &sender_domain,
4804 done = synprot_error(L_smtp_syntax_error, 501, smtp_cmd_data, errmess);
4808 sender_address = raw_sender;
4810 /* If there is a configured size limit for mail, check that this message
4811 doesn't exceed it. The check is postponed to this point so that the sender
4814 if (thismessage_size_limit > 0 && message_size > thismessage_size_limit)
4816 smtp_printf("552 Message size exceeds maximum permitted\r\n", FALSE);
4817 log_write(L_size_reject,
4818 LOG_MAIN|LOG_REJECT, "rejected MAIL FROM:<%s> %s: "
4819 "message too big: size%s=%d max=%d",
4821 host_and_ident(TRUE),
4822 (message_size == INT_MAX)? ">" : "",
4824 thismessage_size_limit);
4825 sender_address = NULL;
4829 /* Check there is enough space on the disk unless configured not to.
4830 When smtp_check_spool_space is set, the check is for thismessage_size_limit
4831 plus the current message - i.e. we accept the message only if it won't
4832 reduce the space below the threshold. Add 5000 to the size to allow for
4833 overheads such as the Received: line and storing of recipients, etc.
4834 By putting the check here, even when SIZE is not given, it allow VRFY
4835 and EXPN etc. to be used when space is short. */
4837 if (!receive_check_fs(
4838 (smtp_check_spool_space && message_size >= 0)?
4839 message_size + 5000 : 0))
4841 smtp_printf("452 Space shortage, please try later\r\n", FALSE);
4842 sender_address = NULL;
4846 /* If sender_address is unqualified, reject it, unless this is a locally
4847 generated message, or the sending host or net is permitted to send
4848 unqualified addresses - typically local machines behaving as MUAs -
4849 in which case just qualify the address. The flag is set above at the start
4850 of the SMTP connection. */
4852 if (!sender_domain && *sender_address)
4853 if (f.allow_unqualified_sender)
4855 sender_domain = Ustrlen(sender_address) + 1;
4856 sender_address = rewrite_address_qualify(sender_address, FALSE);
4857 DEBUG(D_receive) debug_printf("unqualified address %s accepted\n",
4862 smtp_printf("501 %s: sender address must contain a domain\r\n", FALSE,
4864 log_write(L_smtp_syntax_error,
4865 LOG_MAIN|LOG_REJECT,
4866 "unqualified sender rejected: <%s> %s%s",
4868 host_and_ident(TRUE),
4870 sender_address = NULL;
4874 /* Apply an ACL check if one is defined, before responding. Afterwards,
4875 when pipelining is not advertised, do another sync check in case the ACL
4876 delayed and the client started sending in the meantime. */
4880 rc = acl_check(ACL_WHERE_MAIL, NULL, acl_smtp_mail, &user_msg, &log_msg);
4881 if (rc == OK && !f.smtp_in_pipelining_advertised && !check_sync())
4887 if (rc == OK || rc == DISCARD)
4889 BOOL more = pipeline_response();
4892 smtp_printf("%s%s%s", more, US"250 OK",
4893 #ifndef DISABLE_PRDR
4894 prdr_requested ? US", PRDR Requested" : US"",
4901 #ifndef DISABLE_PRDR
4903 user_msg = string_sprintf("%s%s", user_msg, US", PRDR Requested");
4905 smtp_user_msg(US"250", user_msg);
4907 smtp_delay_rcpt = smtp_rlr_base;
4908 f.recipients_discarded = (rc == DISCARD);
4909 was_rej_mail = FALSE;
4913 done = smtp_handle_acl_fail(ACL_WHERE_MAIL, rc, user_msg, log_msg);
4914 sender_address = NULL;
4919 /* The RCPT command requires an address as an operand. There may be any
4920 number of RCPT commands, specifying multiple recipients. We build them all
4921 into a data structure. The start/end values given by parse_extract_address
4922 are not used, as we keep only the extracted address. */
4927 was_rcpt = fl.rcpt_in_progress = TRUE;
4929 /* There must be a sender address; if the sender was rejected and
4930 pipelining was advertised, we assume the client was pipelining, and do not
4931 count this as a protocol error. Reset was_rej_mail so that further RCPTs
4932 get the same treatment. */
4934 if (sender_address == NULL)
4936 if (f.smtp_in_pipelining_advertised && last_was_rej_mail)
4938 smtp_printf("503 sender not yet given\r\n", FALSE);
4939 was_rej_mail = TRUE;
4943 done = synprot_error(L_smtp_protocol_error, 503, NULL,
4944 US"sender not yet given");
4945 was_rcpt = FALSE; /* Not a valid RCPT */
4951 /* Check for an operand */
4953 if (smtp_cmd_data[0] == 0)
4955 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4956 US"RCPT must have an address operand");
4961 /* Set the DSN flags orcpt and dsn_flags from the session*/
4965 if (fl.esmtp) for(;;)
4967 uschar *name, *value;
4969 if (!extract_option(&name, &value))
4972 if (fl.dsn_advertised && strcmpic(name, US"ORCPT") == 0)
4974 /* Check whether orcpt has been already set */
4977 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4978 US"ORCPT can be specified once only");
4981 orcpt = string_copy(value);
4982 DEBUG(D_receive) debug_printf("DSN orcpt: %s\n", orcpt);
4985 else if (fl.dsn_advertised && strcmpic(name, US"NOTIFY") == 0)
4987 /* Check if the notify flags have been already set */
4990 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4991 US"NOTIFY can be specified once only");
4994 if (strcmpic(value, US"NEVER") == 0)
4995 flags |= rf_notify_never;
5002 while (*pp != 0 && *pp != ',') pp++;
5003 if (*pp == ',') *pp++ = 0;
5004 if (strcmpic(p, US"SUCCESS") == 0)
5006 DEBUG(D_receive) debug_printf("DSN: Setting notify success\n");
5007 flags |= rf_notify_success;
5009 else if (strcmpic(p, US"FAILURE") == 0)
5011 DEBUG(D_receive) debug_printf("DSN: Setting notify failure\n");
5012 flags |= rf_notify_failure;
5014 else if (strcmpic(p, US"DELAY") == 0)
5016 DEBUG(D_receive) debug_printf("DSN: Setting notify delay\n");
5017 flags |= rf_notify_delay;
5021 /* Catch any strange values */
5022 done = synprot_error(L_smtp_syntax_error, 501, NULL,
5023 US"Invalid value for NOTIFY parameter");
5028 DEBUG(D_receive) debug_printf("DSN Flags: %x\n", flags);
5032 /* Unknown option. Stick back the terminator characters and break
5033 the loop. An error for a malformed address will occur. */
5037 DEBUG(D_receive) debug_printf("Invalid RCPT option: %s : %s\n", name, value);
5044 /* Apply SMTP rewriting then extract the working address. Don't allow "<>"
5045 as a recipient address */
5047 recipient = rewrite_existflags & rewrite_smtp
5048 ? rewrite_one(smtp_cmd_data, rewrite_smtp, NULL, FALSE, US"",
5049 global_rewrite_rules)
5052 if (!(recipient = parse_extract_address(recipient, &errmess, &start, &end,
5053 &recipient_domain, FALSE)))
5055 done = synprot_error(L_smtp_syntax_error, 501, smtp_cmd_data, errmess);
5060 /* If the recipient address is unqualified, reject it, unless this is a
5061 locally generated message. However, unqualified addresses are permitted
5062 from a configured list of hosts and nets - typically when behaving as
5063 MUAs rather than MTAs. Sad that SMTP is used for both types of traffic,
5064 really. The flag is set at the start of the SMTP connection.
5066 RFC 1123 talks about supporting "the reserved mailbox postmaster"; I always
5067 assumed this meant "reserved local part", but the revision of RFC 821 and
5068 friends now makes it absolutely clear that it means *mailbox*. Consequently
5069 we must always qualify this address, regardless. */
5071 if (!recipient_domain)
5072 if (!(recipient_domain = qualify_recipient(&recipient, smtp_cmd_data,
5079 /* Check maximum allowed */
5081 if (rcpt_count > recipients_max && recipients_max > 0)
5083 if (recipients_max_reject)
5086 smtp_printf("552 too many recipients\r\n", FALSE);
5088 log_write(0, LOG_MAIN|LOG_REJECT, "too many recipients: message "
5089 "rejected: sender=<%s> %s", sender_address, host_and_ident(TRUE));
5094 smtp_printf("452 too many recipients\r\n", FALSE);
5096 log_write(0, LOG_MAIN|LOG_REJECT, "too many recipients: excess "
5097 "temporarily rejected: sender=<%s> %s", sender_address,
5098 host_and_ident(TRUE));
5105 /* If we have passed the threshold for rate limiting, apply the current
5106 delay, and update it for next time, provided this is a limited host. */
5108 if (rcpt_count > smtp_rlr_threshold &&
5109 verify_check_host(&smtp_ratelimit_hosts) == OK)
5111 DEBUG(D_receive) debug_printf("rate limit RCPT: delay %.3g sec\n",
5112 smtp_delay_rcpt/1000.0);
5113 millisleep((int)smtp_delay_rcpt);
5114 smtp_delay_rcpt *= smtp_rlr_factor;
5115 if (smtp_delay_rcpt > (double)smtp_rlr_limit)
5116 smtp_delay_rcpt = (double)smtp_rlr_limit;
5119 /* If the MAIL ACL discarded all the recipients, we bypass ACL checking
5120 for them. Otherwise, check the access control list for this recipient. As
5121 there may be a delay in this, re-check for a synchronization error
5122 afterwards, unless pipelining was advertised. */
5124 if (f.recipients_discarded)
5127 if ( (rc = acl_check(ACL_WHERE_RCPT, recipient, acl_smtp_rcpt, &user_msg,
5129 && !f.smtp_in_pipelining_advertised && !check_sync())
5132 /* The ACL was happy */
5136 BOOL more = pipeline_response();
5139 smtp_user_msg(US"250", user_msg);
5141 smtp_printf("250 Accepted\r\n", more);
5142 receive_add_recipient(recipient, -1);
5144 /* Set the dsn flags in the recipients_list */
5145 recipients_list[recipients_count-1].orcpt = orcpt;
5146 recipients_list[recipients_count-1].dsn_flags = flags;
5148 DEBUG(D_receive) debug_printf("DSN: orcpt: %s flags: %d\n",
5149 recipients_list[recipients_count-1].orcpt,
5150 recipients_list[recipients_count-1].dsn_flags);
5153 /* The recipient was discarded */
5155 else if (rc == DISCARD)
5158 smtp_user_msg(US"250", user_msg);
5160 smtp_printf("250 Accepted\r\n", FALSE);
5163 log_write(0, LOG_MAIN|LOG_REJECT, "%s F=<%s> RCPT %s: "
5164 "discarded by %s ACL%s%s", host_and_ident(TRUE),
5165 sender_address_unrewritten? sender_address_unrewritten : sender_address,
5166 smtp_cmd_argument, f.recipients_discarded? "MAIL" : "RCPT",
5167 log_msg ? US": " : US"", log_msg ? log_msg : US"");
5170 /* Either the ACL failed the address, or it was deferred. */
5174 if (rc == FAIL) rcpt_fail_count++; else rcpt_defer_count++;
5175 done = smtp_handle_acl_fail(ACL_WHERE_RCPT, rc, user_msg, log_msg);
5180 /* The DATA command is legal only if it follows successful MAIL FROM
5181 and RCPT TO commands. However, if pipelining is advertised, a bad DATA is
5182 not counted as a protocol error if it follows RCPT (which must have been
5183 rejected if there are no recipients.) This function is complete when a
5184 valid DATA command is encountered.
5186 Note concerning the code used: RFC 2821 says this:
5188 - If there was no MAIL, or no RCPT, command, or all such commands
5189 were rejected, the server MAY return a "command out of sequence"
5190 (503) or "no valid recipients" (554) reply in response to the
5193 The example in the pipelining RFC 2920 uses 554, but I use 503 here
5194 because it is the same whether pipelining is in use or not.
5196 If all the RCPT commands that precede DATA provoked the same error message
5197 (often indicating some kind of system error), it is helpful to include it
5198 with the DATA rejection (an idea suggested by Tony Finch). */
5205 if (chunking_state != CHUNKING_OFFERED)
5207 done = synprot_error(L_smtp_protocol_error, 503, NULL,
5208 US"BDAT command used when CHUNKING not advertised");
5212 /* grab size, endmarker */
5214 if (sscanf(CS smtp_cmd_data, "%u %n", &chunking_datasize, &n) < 1)
5216 done = synprot_error(L_smtp_protocol_error, 501, NULL,
5217 US"missing size for BDAT command");
5220 chunking_state = strcmpic(smtp_cmd_data+n, US"LAST") == 0
5221 ? CHUNKING_LAST : CHUNKING_ACTIVE;
5222 chunking_data_left = chunking_datasize;
5223 DEBUG(D_receive) debug_printf("chunking state %d, %d bytes\n",
5224 (int)chunking_state, chunking_data_left);
5226 /* push the current receive_* function on the "stack", and
5227 replace them by bdat_getc(), which in turn will use the lwr_receive_*
5228 functions to do the dirty work. */
5229 lwr_receive_getc = receive_getc;
5230 lwr_receive_getbuf = receive_getbuf;
5231 lwr_receive_ungetc = receive_ungetc;
5233 receive_getc = bdat_getc;
5234 receive_ungetc = bdat_ungetc;
5245 DATA_BDAT: /* Common code for DATA and BDAT */
5246 if (!discarded && recipients_count <= 0)
5248 if (fl.rcpt_smtp_response_same && rcpt_smtp_response != NULL)
5250 uschar *code = US"503";
5251 int len = Ustrlen(rcpt_smtp_response);
5252 smtp_respond(code, 3, FALSE, US"All RCPT commands were rejected with "
5254 /* Responses from smtp_printf() will have \r\n on the end */
5255 if (len > 2 && rcpt_smtp_response[len-2] == '\r')
5256 rcpt_smtp_response[len-2] = 0;
5257 smtp_respond(code, 3, FALSE, rcpt_smtp_response);
5259 if (f.smtp_in_pipelining_advertised && last_was_rcpt)
5260 smtp_printf("503 Valid RCPT command must precede %s\r\n", FALSE,
5261 smtp_names[smtp_connection_had[smtp_ch_index-1]]);
5263 done = synprot_error(L_smtp_protocol_error, 503, NULL,
5264 smtp_connection_had[smtp_ch_index-1] == SCH_DATA
5265 ? US"valid RCPT command must precede DATA"
5266 : US"valid RCPT command must precede BDAT");
5268 if (chunking_state > CHUNKING_OFFERED)
5273 if (toomany && recipients_max_reject)
5275 sender_address = NULL; /* This will allow a new MAIL without RSET */
5276 sender_address_unrewritten = NULL;
5277 smtp_printf("554 Too many recipients\r\n", FALSE);
5281 if (chunking_state > CHUNKING_OFFERED)
5282 rc = OK; /* No predata ACL or go-ahead output for BDAT */
5285 /* If there is an ACL, re-check the synchronization afterwards, since the
5286 ACL may have delayed. To handle cutthrough delivery enforce a dummy call
5287 to get the DATA command sent. */
5289 if (acl_smtp_predata == NULL && cutthrough.cctx.sock < 0)
5293 uschar * acl = acl_smtp_predata ? acl_smtp_predata : US"accept";
5294 f.enable_dollar_recipients = TRUE;
5295 rc = acl_check(ACL_WHERE_PREDATA, NULL, acl, &user_msg,
5297 f.enable_dollar_recipients = FALSE;
5298 if (rc == OK && !check_sync())
5302 { /* Either the ACL failed the address, or it was deferred. */
5303 done = smtp_handle_acl_fail(ACL_WHERE_PREDATA, rc, user_msg, log_msg);
5309 smtp_user_msg(US"354", user_msg);
5312 "354 Enter message, ending with \".\" on a line by itself\r\n", FALSE);
5316 if (smtp_in) /* all ACKs needed to ramp window up for bulk data */
5317 (void) setsockopt(fileno(smtp_in), IPPROTO_TCP, TCP_QUICKACK,
5318 US &on, sizeof(on));
5321 message_ended = END_NOTENDED; /* Indicate in middle of data */
5332 if (!(address = parse_extract_address(smtp_cmd_data, &errmess,
5333 &start, &end, &recipient_domain, FALSE)))
5335 smtp_printf("501 %s\r\n", FALSE, errmess);
5339 if (!recipient_domain)
5340 if (!(recipient_domain = qualify_recipient(&address, smtp_cmd_data,
5344 if ((rc = acl_check(ACL_WHERE_VRFY, address, acl_smtp_vrfy,
5345 &user_msg, &log_msg)) != OK)
5346 done = smtp_handle_acl_fail(ACL_WHERE_VRFY, rc, user_msg, log_msg);
5350 address_item * addr = deliver_make_addr(address, FALSE);
5352 switch(verify_address(addr, NULL, vopt_is_recipient | vopt_qualify, -1,
5353 -1, -1, NULL, NULL, NULL))
5356 s = string_sprintf("250 <%s> is deliverable", address);
5360 s = (addr->user_message != NULL)?
5361 string_sprintf("451 <%s> %s", address, addr->user_message) :
5362 string_sprintf("451 Cannot resolve <%s> at this time", address);
5366 s = (addr->user_message != NULL)?
5367 string_sprintf("550 <%s> %s", address, addr->user_message) :
5368 string_sprintf("550 <%s> is not deliverable", address);
5369 log_write(0, LOG_MAIN, "VRFY failed for %s %s",
5370 smtp_cmd_argument, host_and_ident(TRUE));
5374 smtp_printf("%s\r\n", FALSE, s);
5382 rc = acl_check(ACL_WHERE_EXPN, NULL, acl_smtp_expn, &user_msg, &log_msg);
5384 done = smtp_handle_acl_fail(ACL_WHERE_EXPN, rc, user_msg, log_msg);
5387 BOOL save_log_testing_mode = f.log_testing_mode;
5388 f.address_test_mode = f.log_testing_mode = TRUE;
5389 (void) verify_address(deliver_make_addr(smtp_cmd_data, FALSE),
5390 smtp_out, vopt_is_recipient | vopt_qualify | vopt_expn, -1, -1, -1,
5392 f.address_test_mode = FALSE;
5393 f.log_testing_mode = save_log_testing_mode; /* true for -bh */
5402 if (!fl.tls_advertised)
5404 done = synprot_error(L_smtp_protocol_error, 503, NULL,
5405 US"STARTTLS command used when not advertised");
5409 /* Apply an ACL check if one is defined */
5411 if ( acl_smtp_starttls
5412 && (rc = acl_check(ACL_WHERE_STARTTLS, NULL, acl_smtp_starttls,
5413 &user_msg, &log_msg)) != OK
5416 done = smtp_handle_acl_fail(ACL_WHERE_STARTTLS, rc, user_msg, log_msg);
5420 /* RFC 2487 is not clear on when this command may be sent, though it
5421 does state that all information previously obtained from the client
5422 must be discarded if a TLS session is started. It seems reasonable to
5423 do an implied RSET when STARTTLS is received. */
5425 incomplete_transaction_log(US"STARTTLS");
5426 cancel_cutthrough_connection(TRUE, US"STARTTLS received");
5427 smtp_reset(reset_point);
5429 cmd_list[CMD_LIST_STARTTLS].is_mail_cmd = FALSE;
5431 /* There's an attack where more data is read in past the STARTTLS command
5432 before TLS is negotiated, then assumed to be part of the secure session
5433 when used afterwards; we use segregated input buffers, so are not
5434 vulnerable, but we want to note when it happens and, for sheer paranoia,
5435 ensure that the buffer is "wiped".
5436 Pipelining sync checks will normally have protected us too, unless disabled
5437 by configuration. */
5439 if (receive_smtp_buffered())
5442 debug_printf("Non-empty input buffer after STARTTLS; naive attack?\n");
5443 if (tls_in.active.sock < 0)
5444 smtp_inend = smtp_inptr = smtp_inbuffer;
5445 /* and if TLS is already active, tls_server_start() should fail */
5448 /* There is nothing we value in the input buffer and if TLS is successfully
5449 negotiated, we won't use this buffer again; if TLS fails, we'll just read
5450 fresh content into it. The buffer contains arbitrary content from an
5451 untrusted remote source; eg: NOOP <shellcode>\r\nSTARTTLS\r\n
5452 It seems safest to just wipe away the content rather than leave it as a
5453 target to jump to. */
5455 memset(smtp_inbuffer, 0, IN_BUFFER_SIZE);
5457 /* Attempt to start up a TLS session, and if successful, discard all
5458 knowledge that was obtained previously. At least, that's what the RFC says,
5459 and that's what happens by default. However, in order to work round YAEB,
5460 there is an option to remember the esmtp state. Sigh.
5462 We must allow for an extra EHLO command and an extra AUTH command after
5463 STARTTLS that don't add to the nonmail command count. */
5466 if ((rc = tls_server_start(tls_require_ciphers, &s)) == OK)
5468 if (!tls_remember_esmtp)
5469 fl.helo_seen = fl.esmtp = fl.auth_advertised = f.smtp_in_pipelining_advertised = FALSE;
5470 cmd_list[CMD_LIST_EHLO].is_mail_cmd = TRUE;
5471 cmd_list[CMD_LIST_AUTH].is_mail_cmd = TRUE;
5472 cmd_list[CMD_LIST_TLS_AUTH].is_mail_cmd = TRUE;
5473 if (sender_helo_name)
5475 store_free(sender_helo_name);
5476 sender_helo_name = NULL;
5477 host_build_sender_fullhost(); /* Rebuild */
5478 set_process_info("handling incoming TLS connection from %s",
5479 host_and_ident(FALSE));
5482 (sender_host_address ? protocols : protocols_local)
5484 ? pextend + (sender_host_authenticated ? pauthed : 0)
5486 + (tls_in.active.sock >= 0 ? pcrpted : 0)
5489 sender_host_auth_pubname = sender_host_authenticated = NULL;
5490 authenticated_id = NULL;
5491 sync_cmd_limit = NON_SYNC_CMD_NON_PIPELINING;
5492 DEBUG(D_tls) debug_printf("TLS active\n");
5493 break; /* Successful STARTTLS */
5496 (void) smtp_log_tls_fail(s);
5498 /* Some local configuration problem was discovered before actually trying
5499 to do a TLS handshake; give a temporary error. */
5503 smtp_printf("454 TLS currently unavailable\r\n", FALSE);
5507 /* Hard failure. Reject everything except QUIT or closed connection. One
5508 cause for failure is a nested STARTTLS, in which case tls_in.active remains
5509 set, but we must still reject all incoming commands. */
5511 DEBUG(D_tls) debug_printf("TLS failed to start\n");
5512 while (done <= 0) switch(smtp_read_command(FALSE, GETC_BUFFER_UNLIMITED))
5515 log_write(L_smtp_connection, LOG_MAIN, "%s closed by EOF",
5516 smtp_get_connection_info());
5517 smtp_notquit_exit(US"tls-failed", NULL, NULL);
5521 /* It is perhaps arguable as to which exit ACL should be called here,
5522 but as it is probably a situation that almost never arises, it
5523 probably doesn't matter. We choose to call the real QUIT ACL, which in
5524 some sense is perhaps "right". */
5529 && ((rc = acl_check(ACL_WHERE_QUIT, NULL, acl_smtp_quit, &user_msg,
5530 &log_msg)) == ERROR))
5531 log_write(0, LOG_MAIN|LOG_PANIC, "ACL for QUIT returned ERROR: %s",
5534 smtp_respond(US"221", 3, TRUE, user_msg);
5536 smtp_printf("221 %s closing connection\r\n", FALSE, smtp_active_hostname);
5537 log_write(L_smtp_connection, LOG_MAIN, "%s closed by QUIT",
5538 smtp_get_connection_info());
5543 smtp_printf("554 Security failure\r\n", FALSE);
5546 tls_close(NULL, TLS_SHUTDOWN_NOWAIT);
5551 /* The ACL for QUIT is provided for gathering statistical information or
5552 similar; it does not affect the response code, but it can supply a custom
5556 smtp_quit_handler(&user_msg, &log_msg);
5562 smtp_rset_handler();
5563 cancel_cutthrough_connection(TRUE, US"RSET received");
5564 smtp_reset(reset_point);
5571 smtp_printf("250 OK\r\n", FALSE);
5575 /* Show ETRN/EXPN/VRFY if there's an ACL for checking hosts; if actually
5576 used, a check will be done for permitted hosts. Show STARTTLS only if not
5577 already in a TLS session and if it would be advertised in the EHLO
5582 smtp_printf("214-Commands supported:\r\n", TRUE);
5586 Ustrcat(buffer, " AUTH");
5588 if (tls_in.active.sock < 0 &&
5589 verify_check_host(&tls_advertise_hosts) != FAIL)
5590 Ustrcat(buffer, " STARTTLS");
5592 Ustrcat(buffer, " HELO EHLO MAIL RCPT DATA BDAT");
5593 Ustrcat(buffer, " NOOP QUIT RSET HELP");
5594 if (acl_smtp_etrn != NULL) Ustrcat(buffer, " ETRN");
5595 if (acl_smtp_expn != NULL) Ustrcat(buffer, " EXPN");
5596 if (acl_smtp_vrfy != NULL) Ustrcat(buffer, " VRFY");
5597 smtp_printf("214%s\r\n", FALSE, buffer);
5603 incomplete_transaction_log(US"connection lost");
5604 smtp_notquit_exit(US"connection-lost", US"421",
5605 US"%s lost input connection", smtp_active_hostname);
5607 /* Don't log by default unless in the middle of a message, as some mailers
5608 just drop the call rather than sending QUIT, and it clutters up the logs.
5611 if (sender_address || recipients_count > 0)
5612 log_write(L_lost_incoming_connection, LOG_MAIN,
5613 "unexpected %s while reading SMTP command from %s%s%s D=%s",
5614 f.sender_host_unknown ? "EOF" : "disconnection",
5615 f.tcp_in_fastopen && !f.tcp_in_fastopen_logged ? US"TFO " : US"",
5616 host_and_ident(FALSE), smtp_read_error,
5617 string_timesince(&smtp_connection_start)
5621 log_write(L_smtp_connection, LOG_MAIN, "%s %slost%s D=%s",
5622 smtp_get_connection_info(),
5623 f.tcp_in_fastopen && !f.tcp_in_fastopen_logged ? US"TFO " : US"",
5625 string_timesince(&smtp_connection_start)
5636 done = synprot_error(L_smtp_protocol_error, 503, NULL,
5637 US"ETRN is not permitted inside a transaction");
5641 log_write(L_etrn, LOG_MAIN, "ETRN %s received from %s", smtp_cmd_argument,
5642 host_and_ident(FALSE));
5644 if ((rc = acl_check(ACL_WHERE_ETRN, NULL, acl_smtp_etrn,
5645 &user_msg, &log_msg)) != OK)
5647 done = smtp_handle_acl_fail(ACL_WHERE_ETRN, rc, user_msg, log_msg);
5651 /* Compute the serialization key for this command. */
5653 etrn_serialize_key = string_sprintf("etrn-%s\n", smtp_cmd_data);
5655 /* If a command has been specified for running as a result of ETRN, we
5656 permit any argument to ETRN. If not, only the # standard form is permitted,
5657 since that is strictly the only kind of ETRN that can be implemented
5658 according to the RFC. */
5660 if (smtp_etrn_command)
5664 etrn_command = smtp_etrn_command;
5665 deliver_domain = smtp_cmd_data;
5666 rc = transport_set_up_command(&argv, smtp_etrn_command, TRUE, 0, NULL,
5667 US"ETRN processing", &error);
5668 deliver_domain = NULL;
5671 log_write(0, LOG_MAIN|LOG_PANIC, "failed to set up ETRN command: %s",
5673 smtp_printf("458 Internal failure\r\n", FALSE);
5678 /* Else set up to call Exim with the -R option. */
5682 if (*smtp_cmd_data++ != '#')
5684 done = synprot_error(L_smtp_syntax_error, 501, NULL,
5685 US"argument must begin with #");
5688 etrn_command = US"exim -R";
5689 argv = CUSS child_exec_exim(CEE_RETURN_ARGV, TRUE, NULL, TRUE,
5690 *queue_name ? 4 : 2,
5691 US"-R", smtp_cmd_data,
5692 US"-MCG", queue_name);
5695 /* If we are host-testing, don't actually do anything. */
5701 debug_printf("ETRN command is: %s\n", etrn_command);
5702 debug_printf("ETRN command execution skipped\n");
5704 if (user_msg == NULL) smtp_printf("250 OK\r\n", FALSE);
5705 else smtp_user_msg(US"250", user_msg);
5710 /* If ETRN queue runs are to be serialized, check the database to
5711 ensure one isn't already running. */
5713 if (smtp_etrn_serialize && !enq_start(etrn_serialize_key, 1))
5715 smtp_printf("458 Already processing %s\r\n", FALSE, smtp_cmd_data);
5719 /* Fork a child process and run the command. We don't want to have to
5720 wait for the process at any point, so set SIGCHLD to SIG_IGN before
5721 forking. It should be set that way anyway for external incoming SMTP,
5722 but we save and restore to be tidy. If serialization is required, we
5723 actually run the command in yet another process, so we can wait for it
5724 to complete and then remove the serialization lock. */
5726 oldsignal = signal(SIGCHLD, SIG_IGN);
5728 if ((pid = fork()) == 0)
5730 smtp_input = FALSE; /* This process is not associated with the */
5731 (void)fclose(smtp_in); /* SMTP call any more. */
5732 (void)fclose(smtp_out);
5734 signal(SIGCHLD, SIG_DFL); /* Want to catch child */
5736 /* If not serializing, do the exec right away. Otherwise, fork down
5737 into another process. */
5739 if (!smtp_etrn_serialize || (pid = fork()) == 0)
5741 DEBUG(D_exec) debug_print_argv(argv);
5742 exim_nullstd(); /* Ensure std{in,out,err} exist */
5743 execv(CS argv[0], (char *const *)argv);
5744 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "exec of \"%s\" (ETRN) failed: %s",
5745 etrn_command, strerror(errno));
5746 _exit(EXIT_FAILURE); /* paranoia */
5749 /* Obey this if smtp_serialize and the 2nd fork yielded non-zero. That
5750 is, we are in the first subprocess, after forking again. All we can do
5751 for a failing fork is to log it. Otherwise, wait for the 2nd process to
5752 complete, before removing the serialization. */
5755 log_write(0, LOG_MAIN|LOG_PANIC, "2nd fork for serialized ETRN "
5756 "failed: %s", strerror(errno));
5760 DEBUG(D_any) debug_printf("waiting for serialized ETRN process %d\n",
5762 (void)wait(&status);
5763 DEBUG(D_any) debug_printf("serialized ETRN process %d ended\n",
5767 enq_end(etrn_serialize_key);
5768 _exit(EXIT_SUCCESS);
5771 /* Back in the top level SMTP process. Check that we started a subprocess
5772 and restore the signal state. */
5776 log_write(0, LOG_MAIN|LOG_PANIC, "fork of process for ETRN failed: %s",
5778 smtp_printf("458 Unable to fork process\r\n", FALSE);
5779 if (smtp_etrn_serialize) enq_end(etrn_serialize_key);
5783 if (user_msg == NULL) smtp_printf("250 OK\r\n", FALSE);
5784 else smtp_user_msg(US"250", user_msg);
5787 signal(SIGCHLD, oldsignal);
5792 done = synprot_error(L_smtp_syntax_error, 501, NULL,
5793 US"unexpected argument data");
5797 /* This currently happens only for NULLs, but could be extended. */
5800 done = synprot_error(L_smtp_syntax_error, 0, NULL, /* Just logs */
5801 US"NUL character(s) present (shown as '?')");
5802 smtp_printf("501 NUL characters are not allowed in SMTP commands\r\n",
5809 if (smtp_inend >= smtp_inbuffer + IN_BUFFER_SIZE)
5810 smtp_inend = smtp_inbuffer + IN_BUFFER_SIZE - 1;
5811 c = smtp_inend - smtp_inptr;
5812 if (c > 150) c = 150; /* limit logged amount */
5814 incomplete_transaction_log(US"sync failure");
5815 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP protocol synchronization error "
5816 "(next input sent too soon: pipelining was%s advertised): "
5817 "rejected \"%s\" %s next input=\"%s\"",
5818 f.smtp_in_pipelining_advertised ? "" : " not",
5819 smtp_cmd_buffer, host_and_ident(TRUE),
5820 string_printing(smtp_inptr));
5821 smtp_notquit_exit(US"synchronization-error", US"554",
5822 US"SMTP synchronization error");
5823 done = 1; /* Pretend eof - drops connection */
5827 case TOO_MANY_NONMAIL_CMD:
5828 s = smtp_cmd_buffer;
5829 while (*s != 0 && !isspace(*s)) s++;
5830 incomplete_transaction_log(US"too many non-mail commands");
5831 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
5832 "nonmail commands (last was \"%.*s\")", host_and_ident(FALSE),
5833 (int)(s - smtp_cmd_buffer), smtp_cmd_buffer);
5834 smtp_notquit_exit(US"bad-commands", US"554", US"Too many nonmail commands");
5835 done = 1; /* Pretend eof - drops connection */
5838 #ifdef SUPPORT_PROXY
5839 case PROXY_FAIL_IGNORE_CMD:
5840 smtp_printf("503 Command refused, required Proxy negotiation failed\r\n", FALSE);
5845 if (unknown_command_count++ >= smtp_max_unknown_commands)
5847 log_write(L_smtp_syntax_error, LOG_MAIN,
5848 "SMTP syntax error in \"%s\" %s %s",
5849 string_printing(smtp_cmd_buffer), host_and_ident(TRUE),
5850 US"unrecognized command");
5851 incomplete_transaction_log(US"unrecognized command");
5852 smtp_notquit_exit(US"bad-commands", US"500",
5853 US"Too many unrecognized commands");
5855 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
5856 "unrecognized commands (last was \"%s\")", host_and_ident(FALSE),
5857 string_printing(smtp_cmd_buffer));
5860 done = synprot_error(L_smtp_syntax_error, 500, NULL,
5861 US"unrecognized command");
5865 /* This label is used by goto's inside loops that want to break out to
5866 the end of the command-processing loop. */
5869 last_was_rej_mail = was_rej_mail; /* Remember some last commands for */
5870 last_was_rcpt = was_rcpt; /* protocol error handling */
5874 return done - 2; /* Convert yield values */
5880 authres_smtpauth(gstring * g)
5882 if (!sender_host_authenticated)
5885 g = string_append(g, 2, US";\n\tauth=pass (", sender_host_auth_pubname);
5887 if (Ustrcmp(sender_host_auth_pubname, "tls") != 0)
5888 g = string_append(g, 2, US") smtp.auth=", authenticated_id);
5889 else if (authenticated_id)
5890 g = string_append(g, 2, US") x509.auth=", authenticated_id);
5892 g = string_catn(g, US") reason=x509.auth", 17);
5894 if (authenticated_sender)
5895 g = string_append(g, 2, US" smtp.mailfrom=", authenticated_sender);
5903 /* End of smtp_in.c */