1 /*************************************************
2 * Exim - an Internet mail transport agent *
3 *************************************************/
5 /* Copyright (c) The Exim Maintainers 2020 - 2022 */
6 /* Copyright (c) University of Cambridge 1995 - 2018 */
7 /* See the file NOTICE for conditions of use and distribution. */
8 /* SPDX-License-Identifier: GPL-2.0-or-later */
10 /* Functions for handling an incoming SMTP call. */
17 /* Initialize for TCP wrappers if so configured. It appears that the macro
18 HAVE_IPV6 is used in some versions of the tcpd.h header, so we unset it before
19 including that header, and restore its value afterwards. */
21 #ifdef USE_TCP_WRAPPERS
24 #define EXIM_HAVE_IPV6
30 #define HAVE_IPV6 TRUE
33 int allow_severity = LOG_INFO;
34 int deny_severity = LOG_NOTICE;
35 uschar *tcp_wrappers_name;
39 /* Size of buffer for reading SMTP commands. We used to use 512, as defined
40 by RFC 821. However, RFC 1869 specifies that this must be increased for SMTP
41 commands that accept arguments, and this in particular applies to AUTH, where
42 the data can be quite long. More recently this value was 2048 in Exim;
43 however, RFC 4954 (circa 2007) recommends 12288 bytes to handle AUTH. Clients
44 such as Thunderbird will send an AUTH with an initial-response for GSSAPI.
45 The maximum size of a Kerberos ticket under Windows 2003 is 12000 bytes, and
46 we need room to handle large base64-encoded AUTHs for GSSAPI.
49 #define SMTP_CMD_BUFFER_SIZE 16384
51 /* Size of buffer for reading SMTP incoming packets */
53 #define IN_BUFFER_SIZE 8192
55 /* Structure for SMTP command list */
62 short int is_mail_cmd;
65 /* Codes for identifying commands. We order them so that those that come first
66 are those for which synchronization is always required. Checking this can help
70 /* These commands are required to be synchronized, i.e. to be the last in a
71 block of commands when pipelining. */
73 HELO_CMD, EHLO_CMD, DATA_CMD, /* These are listed in the pipelining */
74 VRFY_CMD, EXPN_CMD, NOOP_CMD, /* RFC as requiring synchronization */
75 ETRN_CMD, /* This by analogy with TURN from the RFC */
76 STARTTLS_CMD, /* Required by the STARTTLS RFC */
77 TLS_AUTH_CMD, /* auto-command at start of SSL */
79 /* This is a dummy to identify the non-sync commands when pipelining */
81 NON_SYNC_CMD_PIPELINING,
83 /* These commands need not be synchronized when pipelining */
85 MAIL_CMD, RCPT_CMD, RSET_CMD,
87 /* This is a dummy to identify the non-sync commands when not pipelining */
89 NON_SYNC_CMD_NON_PIPELINING,
91 /* RFC3030 section 2: "After all MAIL and RCPT responses are collected and
92 processed the message is sent using a series of BDAT commands"
93 implies that BDAT should be synchronized. However, we see Google, at least,
94 sending MAIL,RCPT,BDAT-LAST in a single packet, clearly not waiting for
95 processing of the RCPT response(s). We shall do the same, and not require
96 synch for BDAT. Worse, as the chunk may (very likely will) follow the
97 command-header in the same packet we cannot do the usual "is there any
98 follow-on data after the command line" even for non-pipeline mode.
99 So we'll need an explicit check after reading the expected chunk amount
100 when non-pipe, before sending the ACK. */
104 /* I have been unable to find a statement about the use of pipelining
105 with AUTH, so to be on the safe side it is here, though I kind of feel
106 it should be up there with the synchronized commands. */
110 /* I'm not sure about these, but I don't think they matter. */
115 PROXY_FAIL_IGNORE_CMD,
118 /* These are specials that don't correspond to actual commands */
120 EOF_CMD, OTHER_CMD, BADARG_CMD, BADCHAR_CMD, BADSYN_CMD,
121 TOO_MANY_NONMAIL_CMD };
124 /* This is a convenience macro for adding the identity of an SMTP command
125 to the circular buffer that holds a list of the last n received. */
128 smtp_connection_had[smtp_ch_index++] = n; \
129 if (smtp_ch_index >= SMTP_HBUFF_SIZE) smtp_ch_index = 0
132 /*************************************************
133 * Local static variables *
134 *************************************************/
137 BOOL auth_advertised :1;
139 BOOL tls_advertised :1;
141 BOOL dsn_advertised :1;
143 BOOL helo_verify_required :1;
146 BOOL helo_accept_junk :1;
147 #ifndef DISABLE_PIPE_CONNECT
148 BOOL pipe_connect_acceptable :1;
150 BOOL rcpt_smtp_response_same :1;
151 BOOL rcpt_in_progress :1;
152 BOOL smtp_exit_function_called :1;
154 BOOL smtputf8_advertised :1;
157 .helo_verify_required = FALSE,
158 .helo_verify = FALSE,
159 .smtp_exit_function_called = FALSE,
162 static auth_instance *authenticated_by;
163 static int count_nonmail;
164 static int nonmail_command_count;
165 static int synprot_error_count;
166 static int unknown_command_count;
167 static int sync_cmd_limit;
168 static int smtp_write_error = 0;
170 static uschar *rcpt_smtp_response;
171 static uschar *smtp_data_buffer;
172 static uschar *smtp_cmd_data;
174 /* We need to know the position of RSET, HELO, EHLO, AUTH, and STARTTLS. Their
175 final fields of all except AUTH are forced TRUE at the start of a new message
176 setup, to allow one of each between messages that is not counted as a nonmail
177 command. (In fact, only one of HELO/EHLO is not counted.) Also, we have to
178 allow a new EHLO after starting up TLS.
180 AUTH is "falsely" labelled as a mail command initially, so that it doesn't get
181 counted. However, the flag is changed when AUTH is received, so that multiple
182 failing AUTHs will eventually hit the limit. After a successful AUTH, another
183 AUTH is already forbidden. After a TLS session is started, AUTH's flag is again
184 forced TRUE, to allow for the re-authentication that can happen at that point.
186 QUIT is also "falsely" labelled as a mail command so that it doesn't up the
187 count of non-mail commands and possibly provoke an error.
189 tls_auth is a pseudo-command, never expected in input. It is activated
190 on TLS startup and looks for a tls authenticator. */
192 enum { CL_RSET, CL_HELO, CL_EHLO, CL_AUTH,
198 static smtp_cmd_list cmd_list[] = {
199 /* name len cmd has_arg is_mail_cmd */
201 [CL_RSET] = { "rset", sizeof("rset")-1, RSET_CMD, FALSE, FALSE }, /* First */
202 [CL_HELO] = { "helo", sizeof("helo")-1, HELO_CMD, TRUE, FALSE },
203 [CL_EHLO] = { "ehlo", sizeof("ehlo")-1, EHLO_CMD, TRUE, FALSE },
204 [CL_AUTH] = { "auth", sizeof("auth")-1, AUTH_CMD, TRUE, TRUE },
206 [CL_STLS] = { "starttls", sizeof("starttls")-1, STARTTLS_CMD, FALSE, FALSE },
207 [CL_TLAU] = { "tls_auth", 0, TLS_AUTH_CMD, FALSE, FALSE },
210 /* If you change anything above here, also fix the definitions below. */
212 { "mail from:", sizeof("mail from:")-1, MAIL_CMD, TRUE, TRUE },
213 { "rcpt to:", sizeof("rcpt to:")-1, RCPT_CMD, TRUE, TRUE },
214 { "data", sizeof("data")-1, DATA_CMD, FALSE, TRUE },
215 { "bdat", sizeof("bdat")-1, BDAT_CMD, TRUE, TRUE },
216 { "quit", sizeof("quit")-1, QUIT_CMD, FALSE, TRUE },
217 { "noop", sizeof("noop")-1, NOOP_CMD, TRUE, FALSE },
218 { "etrn", sizeof("etrn")-1, ETRN_CMD, TRUE, FALSE },
219 { "vrfy", sizeof("vrfy")-1, VRFY_CMD, TRUE, FALSE },
220 { "expn", sizeof("expn")-1, EXPN_CMD, TRUE, FALSE },
221 { "help", sizeof("help")-1, HELP_CMD, TRUE, FALSE }
224 /* This list of names is used for performing the smtp_no_mail logging action. */
226 uschar * smtp_names[] =
228 [SCH_NONE] = US"NONE",
229 [SCH_AUTH] = US"AUTH",
230 [SCH_DATA] = US"DATA",
231 [SCH_BDAT] = US"BDAT",
232 [SCH_EHLO] = US"EHLO",
233 [SCH_ETRN] = US"ETRN",
234 [SCH_EXPN] = US"EXPN",
235 [SCH_HELO] = US"HELO",
236 [SCH_HELP] = US"HELP",
237 [SCH_MAIL] = US"MAIL",
238 [SCH_NOOP] = US"NOOP",
239 [SCH_QUIT] = US"QUIT",
240 [SCH_RCPT] = US"RCPT",
241 [SCH_RSET] = US"RSET",
242 [SCH_STARTTLS] = US"STARTTLS",
243 [SCH_VRFY] = US"VRFY",
246 static uschar *protocols_local[] = {
247 US"local-smtp", /* HELO */
248 US"local-smtps", /* The rare case EHLO->STARTTLS->HELO */
249 US"local-esmtp", /* EHLO */
250 US"local-esmtps", /* EHLO->STARTTLS->EHLO */
251 US"local-esmtpa", /* EHLO->AUTH */
252 US"local-esmtpsa" /* EHLO->STARTTLS->EHLO->AUTH */
254 static uschar *protocols[] = {
256 US"smtps", /* The rare case EHLO->STARTTLS->HELO */
257 US"esmtp", /* EHLO */
258 US"esmtps", /* EHLO->STARTTLS->EHLO */
259 US"esmtpa", /* EHLO->AUTH */
260 US"esmtpsa" /* EHLO->STARTTLS->EHLO->AUTH */
265 #define pcrpted 1 /* added to pextend or pnormal */
266 #define pauthed 2 /* added to pextend */
268 /* Sanity check and validate optional args to MAIL FROM: envelope */
271 ENV_MAIL_OPT_SIZE, ENV_MAIL_OPT_BODY, ENV_MAIL_OPT_AUTH,
275 ENV_MAIL_OPT_RET, ENV_MAIL_OPT_ENVID,
281 uschar * name; /* option requested during MAIL cmd */
282 int value; /* enum type */
283 BOOL need_value; /* TRUE requires value (name=value pair format)
284 FALSE is a singleton */
286 static env_mail_type_t env_mail_type_list[] = {
287 { US"SIZE", ENV_MAIL_OPT_SIZE, TRUE },
288 { US"BODY", ENV_MAIL_OPT_BODY, TRUE },
289 { US"AUTH", ENV_MAIL_OPT_AUTH, TRUE },
291 { US"PRDR", ENV_MAIL_OPT_PRDR, FALSE },
293 { US"RET", ENV_MAIL_OPT_RET, TRUE },
294 { US"ENVID", ENV_MAIL_OPT_ENVID, TRUE },
296 { US"SMTPUTF8",ENV_MAIL_OPT_UTF8, FALSE }, /* rfc6531 */
298 /* keep this the last entry */
299 { US"NULL", ENV_MAIL_OPT_NULL, FALSE },
302 /* When reading SMTP from a remote host, we have to use our own versions of the
303 C input-reading functions, in order to be able to flush the SMTP output only
304 when about to read more data from the socket. This is the only way to get
305 optimal performance when the client is using pipelining. Flushing for every
306 command causes a separate packet and reply packet each time; saving all the
307 responses up (when pipelining) combines them into one packet and one response.
309 For simplicity, these functions are used for *all* SMTP input, not only when
310 receiving over a socket. However, after setting up a secure socket (SSL), input
311 is read via the OpenSSL library, and another set of functions is used instead
314 These functions are set in the receive_getc etc. variables and called with the
315 same interface as the C functions. However, since there can only ever be
316 one incoming SMTP call, we just use a single buffer and flags. There is no need
317 to implement a complicated private FILE-like structure.*/
319 static uschar *smtp_inbuffer;
320 static uschar *smtp_inptr;
321 static uschar *smtp_inend;
322 static int smtp_had_eof;
323 static int smtp_had_error;
326 /* forward declarations */
327 static int smtp_read_command(BOOL check_sync, unsigned buffer_lim);
328 static int synprot_error(int type, int code, uschar *data, uschar *errmess);
329 static void smtp_quit_handler(uschar **, uschar **);
330 static void smtp_rset_handler(void);
332 /*************************************************
333 * Log incomplete transactions *
334 *************************************************/
336 /* This function is called after a transaction has been aborted by RSET, QUIT,
337 connection drops or other errors. It logs the envelope information received
338 so far in order to preserve address verification attempts.
340 Argument: string to indicate what aborted the transaction
345 incomplete_transaction_log(uschar * what)
347 if (!sender_address /* No transaction in progress */
348 || !LOGGING(smtp_incomplete_transaction))
351 /* Build list of recipients for logging */
353 if (recipients_count > 0)
355 raw_recipients = store_get(recipients_count * sizeof(uschar *), GET_UNTAINTED);
356 for (int i = 0; i < recipients_count; i++)
357 raw_recipients[i] = recipients_list[i].address;
358 raw_recipients_count = recipients_count;
361 log_write(L_smtp_incomplete_transaction, LOG_MAIN|LOG_SENDER|LOG_RECIPIENTS,
362 "%s incomplete transaction (%s)", host_and_ident(TRUE), what);
368 log_close_event(const uschar * reason)
370 log_write(L_smtp_connection, LOG_MAIN, "%s D=%s closed %s",
371 smtp_get_connection_info(), string_timesince(&smtp_connection_start), reason);
376 smtp_command_timeout_exit(void)
378 log_write(L_lost_incoming_connection,
379 LOG_MAIN, "SMTP command timeout on%s connection from %s D=%s",
380 tls_in.active.sock >= 0 ? " TLS" : "", host_and_ident(FALSE),
381 string_timesince(&smtp_connection_start));
382 if (smtp_batched_input)
383 moan_smtp_batch(NULL, "421 SMTP command timeout"); /* Does not return */
384 smtp_notquit_exit(US"command-timeout", US"421",
385 US"%s: SMTP command timeout - closing connection",
386 smtp_active_hostname);
387 exim_exit(EXIT_FAILURE);
391 smtp_command_sigterm_exit(void)
393 log_close_event(US"after SIGTERM");
394 if (smtp_batched_input)
395 moan_smtp_batch(NULL, "421 SIGTERM received"); /* Does not return */
396 smtp_notquit_exit(US"signal-exit", US"421",
397 US"%s: Service not available - closing connection", smtp_active_hostname);
398 exim_exit(EXIT_FAILURE);
402 smtp_data_timeout_exit(void)
404 log_write(L_lost_incoming_connection, LOG_MAIN,
405 "SMTP data timeout (message abandoned) on connection from %s F=<%s> D=%s",
406 sender_fullhost ? sender_fullhost : US"local process", sender_address,
407 string_timesince(&smtp_connection_start));
408 receive_bomb_out(US"data-timeout", US"SMTP incoming data timeout");
409 /* Does not return */
413 smtp_data_sigint_exit(void)
415 log_close_event(had_data_sigint == SIGTERM ? US"SIGTERM":US"SIGINT");
416 receive_bomb_out(US"signal-exit",
417 US"Service not available - SIGTERM or SIGINT received");
418 /* Does not return */
422 /******************************************************************************/
423 /* SMTP input buffer handling. Most of these are similar to stdio routines. */
428 /* Set up the buffer for inputting using direct read() calls, and arrange to
429 call the local functions instead of the standard C ones. Place a NUL at the
430 end of the buffer to safety-stop C-string reads from it. */
432 if (!(smtp_inbuffer = US malloc(IN_BUFFER_SIZE)))
433 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "malloc() failed for SMTP input buffer");
434 smtp_inbuffer[IN_BUFFER_SIZE-1] = '\0';
436 smtp_inptr = smtp_inend = smtp_inbuffer;
437 smtp_had_eof = smtp_had_error = 0;
442 /* Refill the buffer, and notify DKIM verification code.
443 Return false for error or EOF.
447 smtp_refill(unsigned lim)
451 if (!smtp_out) return FALSE;
453 if (smtp_receive_timeout > 0) ALARM(smtp_receive_timeout);
455 /* Limit amount read, so non-message data is not fed to DKIM.
456 Take care to not touch the safety NUL at the end of the buffer. */
458 rc = read(fileno(smtp_in), smtp_inbuffer, MIN(IN_BUFFER_SIZE-1, lim));
460 if (smtp_receive_timeout > 0) ALARM_CLR(0);
463 /* Must put the error text in fixed store, because this might be during
464 header reading, where it releases unused store above the header. */
467 if (had_command_timeout) /* set by signal handler */
468 smtp_command_timeout_exit(); /* does not return */
469 if (had_command_sigterm)
470 smtp_command_sigterm_exit();
471 if (had_data_timeout)
472 smtp_data_timeout_exit();
474 smtp_data_sigint_exit();
476 smtp_had_error = save_errno;
477 smtp_read_error = string_copy_perm(
478 string_sprintf(" (error: %s)", strerror(save_errno)), FALSE);
485 dkim_exim_verify_feed(smtp_inbuffer, rc);
487 smtp_inend = smtp_inbuffer + rc;
488 smtp_inptr = smtp_inbuffer;
493 /* Check if there is buffered data */
498 return smtp_inptr < smtp_inend;
501 /* SMTP version of getc()
503 This gets the next byte from the SMTP input buffer. If the buffer is empty,
504 it flushes the output, and refills the buffer, with a timeout. The signal
505 handler is set appropriately by the calling function. This function is not used
506 after a connection has negotiated itself into an TLS/SSL state.
508 Arguments: lim Maximum amount to read/buffer
509 Returns: the next character or EOF
513 smtp_getc(unsigned lim)
515 if (!smtp_hasc() && !smtp_refill(lim)) return EOF;
516 return *smtp_inptr++;
519 /* Get many bytes, refilling buffer if needed */
522 smtp_getbuf(unsigned * len)
527 if (!smtp_hasc() && !smtp_refill(*len))
528 { *len = 0; return NULL; }
530 if ((size = smtp_inend - smtp_inptr) > *len) size = *len;
537 /* Copy buffered data to the dkim feed.
538 Called, unless TLS, just before starting to read message headers. */
541 smtp_get_cache(unsigned lim)
544 int n = smtp_inend - smtp_inptr;
548 dkim_exim_verify_feed(smtp_inptr, n);
553 /* SMTP version of ungetc()
554 Puts a character back in the input buffer. Only ever called once.
559 Returns: the character
565 if (smtp_inptr <= smtp_inbuffer) /* NB: NOT smtp_hasc() ! */
566 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "buffer underflow in smtp_ungetc");
573 /* SMTP version of feof()
574 Tests for a previous EOF
577 Returns: non-zero if the eof flag is set
587 /* SMTP version of ferror()
588 Tests for a previous read error, and returns with errno
589 restored to what it was when the error was detected.
592 Returns: non-zero if the error flag is set
598 errno = smtp_had_error;
599 return smtp_had_error;
603 /* Check if a getc will block or not */
606 smtp_could_getc(void)
610 struct timeval tzero = {.tv_sec = 0, .tv_usec = 0};
612 if (smtp_inptr < smtp_inend)
615 fd = fileno(smtp_in);
618 rc = select(fd + 1, (SELECT_ARG2_TYPE *)&fds, NULL, NULL, &tzero);
620 if (rc <= 0) return FALSE; /* Not ready to read */
621 rc = smtp_getc(GETC_BUFFER_UNLIMITED);
622 if (rc < 0) return FALSE; /* End of file or error */
629 /******************************************************************************/
630 /*************************************************
631 * Recheck synchronization *
632 *************************************************/
634 /* Synchronization checks can never be perfect because a packet may be on its
635 way but not arrived when the check is done. Normally, the checks happen when
636 commands are read: Exim ensures that there is no more input in the input buffer.
637 In normal cases, the response to the command will be fast, and there is no
640 However, for some commands an ACL is run, and that can include delays. In those
641 cases, it is useful to do another check on the input just before sending the
642 response. This also applies at the start of a connection. This function does
643 that check by means of the select() function, as long as the facility is not
644 disabled or inappropriate. A failure of select() is ignored.
646 When there is unwanted input, we read it so that it appears in the log of the
650 Returns: TRUE if all is well; FALSE if there is input pending
654 wouldblock_reading(void)
657 if (tls_in.active.sock >= 0)
658 return !tls_could_getc();
661 return !smtp_could_getc();
667 if (!smtp_enforce_sync || !sender_host_address || f.sender_host_notsocket)
670 return wouldblock_reading();
674 /******************************************************************************/
675 /* Variants of the smtp_* input handling functions for use in CHUNKING mode */
677 /* Forward declarations */
678 static inline void bdat_push_receive_functions(void);
679 static inline void bdat_pop_receive_functions(void);
682 /* Get a byte from the smtp input, in CHUNKING mode. Handle ack of the
683 previous BDAT chunk and getting new ones when we run out. Uses the
684 underlying smtp_getc or tls_getc both for that and for getting the
685 (buffered) data byte. EOD signals (an expected) no further data.
686 ERR signals a protocol error, and EOF a closed input stream.
688 Called from read_bdat_smtp() in receive.c for the message body, but also
689 by the headers read loop in receive_msg(); manipulates chunking_state
690 to handle the BDAT command/response.
691 Placed here due to the correlation with the above smtp_getc(), which it wraps,
692 and also by the need to do smtp command/response handling.
694 Arguments: lim (ignored)
695 Returns: the next character or ERR, EOD or EOF
699 bdat_getc(unsigned lim)
701 uschar * user_msg = NULL;
710 if (chunking_data_left > 0)
711 return lwr_receive_getc(chunking_data_left--);
713 bdat_pop_receive_functions();
715 dkim_save = dkim_collect_input;
716 dkim_collect_input = 0;
719 /* Unless PIPELINING was offered, there should be no next command
720 until after we ack that chunk */
722 if (!f.smtp_in_pipelining_advertised && !check_sync())
724 unsigned n = smtp_inend - smtp_inptr;
727 incomplete_transaction_log(US"sync failure");
728 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP protocol synchronization error "
729 "(next input sent too soon: pipelining was not advertised): "
730 "rejected \"%s\" %s next input=\"%s\"%s",
731 smtp_cmd_buffer, host_and_ident(TRUE),
732 string_printing(string_copyn(smtp_inptr, n)),
733 smtp_inend - smtp_inptr > n ? "..." : "");
734 (void) synprot_error(L_smtp_protocol_error, 554, NULL,
735 US"SMTP synchronization error");
736 goto repeat_until_rset;
739 /* If not the last, ack the received chunk. The last response is delayed
740 until after the data ACL decides on it */
742 if (chunking_state == CHUNKING_LAST)
745 dkim_collect_input = dkim_save;
746 dkim_exim_verify_feed(NULL, 0); /* notify EOD */
747 dkim_collect_input = 0;
752 smtp_printf("250 %u byte chunk received\r\n", FALSE, chunking_datasize);
753 chunking_state = CHUNKING_OFFERED;
754 DEBUG(D_receive) debug_printf("chunking state %d\n", (int)chunking_state);
756 /* Expect another BDAT cmd from input. RFC 3030 says nothing about
757 QUIT, RSET or NOOP but handling them seems obvious */
760 switch(smtp_read_command(TRUE, 1))
763 (void) synprot_error(L_smtp_protocol_error, 503, NULL,
764 US"only BDAT permissible after non-LAST BDAT");
767 switch(smtp_read_command(TRUE, 1))
769 case QUIT_CMD: smtp_quit_handler(&user_msg, &log_msg); /*FALLTHROUGH */
770 case EOF_CMD: return EOF;
771 case RSET_CMD: smtp_rset_handler(); return ERR;
772 default: if (synprot_error(L_smtp_protocol_error, 503, NULL,
773 US"only RSET accepted now") > 0)
775 goto repeat_until_rset;
779 smtp_quit_handler(&user_msg, &log_msg);
790 smtp_printf("250 OK\r\n", FALSE);
797 if (sscanf(CS smtp_cmd_data, "%u %n", &chunking_datasize, &n) < 1)
799 (void) synprot_error(L_smtp_protocol_error, 501, NULL,
800 US"missing size for BDAT command");
803 chunking_state = strcmpic(smtp_cmd_data+n, US"LAST") == 0
804 ? CHUNKING_LAST : CHUNKING_ACTIVE;
805 chunking_data_left = chunking_datasize;
806 DEBUG(D_receive) debug_printf("chunking state %d, %d bytes\n",
807 (int)chunking_state, chunking_data_left);
809 if (chunking_datasize == 0)
810 if (chunking_state == CHUNKING_LAST)
814 (void) synprot_error(L_smtp_protocol_error, 504, NULL,
815 US"zero size for BDAT command");
816 goto repeat_until_rset;
819 bdat_push_receive_functions();
821 dkim_collect_input = dkim_save;
823 break; /* to top of main loop */
832 if (chunking_data_left > 0)
833 return lwr_receive_hasc();
838 bdat_getbuf(unsigned * len)
842 if (chunking_data_left <= 0)
843 { *len = 0; return NULL; }
845 if (*len > chunking_data_left) *len = chunking_data_left;
846 buf = lwr_receive_getbuf(len); /* Either smtp_getbuf or tls_getbuf */
847 chunking_data_left -= *len;
852 bdat_flush_data(void)
854 while (chunking_data_left)
856 unsigned n = chunking_data_left;
857 if (!bdat_getbuf(&n)) break;
860 bdat_pop_receive_functions();
861 chunking_state = CHUNKING_OFFERED;
862 DEBUG(D_receive) debug_printf("chunking state %d\n", (int)chunking_state);
867 bdat_push_receive_functions(void)
869 /* push the current receive_* function on the "stack", and
870 replace them by bdat_getc(), which in turn will use the lwr_receive_*
871 functions to do the dirty work. */
872 if (!lwr_receive_getc)
874 lwr_receive_getc = receive_getc;
875 lwr_receive_getbuf = receive_getbuf;
876 lwr_receive_hasc = receive_hasc;
877 lwr_receive_ungetc = receive_ungetc;
881 DEBUG(D_receive) debug_printf("chunking double-push receive functions\n");
884 receive_getc = bdat_getc;
885 receive_getbuf = bdat_getbuf;
886 receive_hasc = bdat_hasc;
887 receive_ungetc = bdat_ungetc;
891 bdat_pop_receive_functions(void)
893 if (!lwr_receive_getc)
895 DEBUG(D_receive) debug_printf("chunking double-pop receive functions\n");
898 receive_getc = lwr_receive_getc;
899 receive_getbuf = lwr_receive_getbuf;
900 receive_hasc = lwr_receive_hasc;
901 receive_ungetc = lwr_receive_ungetc;
903 lwr_receive_getc = NULL;
904 lwr_receive_getbuf = NULL;
905 lwr_receive_hasc = NULL;
906 lwr_receive_ungetc = NULL;
912 chunking_data_left++;
913 bdat_push_receive_functions(); /* we're not done yet, calling push is safe, because it checks the state before pushing anything */
914 return lwr_receive_ungetc(ch);
919 /******************************************************************************/
921 /*************************************************
922 * Write formatted string to SMTP channel *
923 *************************************************/
925 /* This is a separate function so that we don't have to repeat everything for
926 TLS support or debugging. It is global so that the daemon and the
927 authentication functions can use it. It does not return any error indication,
928 because major problems such as dropped connections won't show up till an output
929 flush for non-TLS connections. The smtp_fflush() function is available for
930 checking that: for convenience, TLS output errors are remembered here so that
931 they are also picked up later by smtp_fflush().
933 This function is exposed to the local_scan API; do not change the signature.
937 more further data expected
938 ... optional arguments
944 smtp_printf(const char *format, BOOL more, ...)
949 smtp_vprintf(format, more, ap);
953 /* This is split off so that verify.c:respond_printf() can, in effect, call
954 smtp_printf(), bearing in mind that in C a vararg function can't directly
955 call another vararg function, only a function which accepts a va_list.
957 This function is exposed to the local_scan API; do not change the signature.
959 /*XXX consider passing caller-info in, for string_vformat-onward */
962 smtp_vprintf(const char *format, BOOL more, va_list ap)
964 gstring gs = { .size = big_buffer_size, .ptr = 0, .s = big_buffer };
967 /* Use taint-unchecked routines for writing into big_buffer, trusting
968 that we'll never expand it. */
970 yield = !! string_vformat(&gs, SVFMT_TAINT_NOCHK, format, ap);
971 string_from_gstring(&gs);
973 DEBUG(D_receive) for (const uschar * t, * s = gs.s;
974 s && (t = Ustrchr(s, '\r'));
975 s = t + 2) /* \r\n */
976 debug_printf("%s %.*s\n",
977 s == gs.s ? "SMTP>>" : " ",
982 log_write(0, LOG_MAIN|LOG_PANIC, "string too large in smtp_printf()");
983 smtp_closedown(US"Unexpected error");
984 exim_exit(EXIT_FAILURE);
987 /* If this is the first output for a (non-batch) RCPT command, see if all RCPTs
988 have had the same. Note: this code is also present in smtp_respond(). It would
989 be tidier to have it only in one place, but when it was added, it was easier to
990 do it that way, so as not to have to mess with the code for the RCPT command,
991 which sometimes uses smtp_printf() and sometimes smtp_respond(). */
993 if (fl.rcpt_in_progress)
995 if (!rcpt_smtp_response)
996 rcpt_smtp_response = string_copy(big_buffer);
997 else if (fl.rcpt_smtp_response_same &&
998 Ustrcmp(rcpt_smtp_response, big_buffer) != 0)
999 fl.rcpt_smtp_response_same = FALSE;
1000 fl.rcpt_in_progress = FALSE;
1003 /* Now write the string */
1007 tls_in.active.sock >= 0 ? (tls_write(NULL, gs.s, gs.ptr, more) < 0) :
1009 (fwrite(gs.s, gs.ptr, 1, smtp_out) == 0)
1011 smtp_write_error = -1;
1016 /*************************************************
1017 * Flush SMTP out and check for error *
1018 *************************************************/
1020 /* This function isn't currently used within Exim (it detects errors when it
1021 tries to read the next SMTP input), but is available for use in local_scan().
1022 It flushes the output and checks for errors.
1025 Returns: 0 for no error; -1 after an error
1031 if (tls_in.active.sock < 0 && fflush(smtp_out) != 0) smtp_write_error = -1;
1035 tls_in.active.sock >= 0 ? (tls_write(NULL, NULL, 0, FALSE) < 0) :
1037 (fflush(smtp_out) != 0)
1039 smtp_write_error = -1;
1041 return smtp_write_error;
1046 /* If there's input waiting (and we're doing pipelineing) then we can pipeline
1047 a reponse with the one following. */
1050 pipeline_response(void)
1052 if ( !smtp_enforce_sync || !sender_host_address
1053 || f.sender_host_notsocket || !f.smtp_in_pipelining_advertised)
1056 if (wouldblock_reading()) return FALSE;
1057 f.smtp_in_pipelining_used = TRUE;
1062 #ifndef DISABLE_PIPE_CONNECT
1064 pipeline_connect_sends(void)
1066 if (!sender_host_address || f.sender_host_notsocket || !fl.pipe_connect_acceptable)
1069 if (wouldblock_reading()) return FALSE;
1070 f.smtp_in_early_pipe_used = TRUE;
1075 /*************************************************
1076 * SMTP command read timeout *
1077 *************************************************/
1079 /* Signal handler for timing out incoming SMTP commands. This attempts to
1082 Argument: signal number (SIGALRM)
1087 command_timeout_handler(int sig)
1089 had_command_timeout = sig;
1094 /*************************************************
1095 * SIGTERM received *
1096 *************************************************/
1098 /* Signal handler for handling SIGTERM. Again, try to finish tidily.
1100 Argument: signal number (SIGTERM)
1105 command_sigterm_handler(int sig)
1107 had_command_sigterm = sig;
1113 /*************************************************
1114 * Read one command line *
1115 *************************************************/
1117 /* Strictly, SMTP commands coming over the net are supposed to end with CRLF.
1118 There are sites that don't do this, and in any case internal SMTP probably
1119 should check only for LF. Consequently, we check here for LF only. The line
1120 ends up with [CR]LF removed from its end. If we get an overlong line, treat as
1121 an unknown command. The command is read into the global smtp_cmd_buffer so that
1122 it is available via $smtp_command.
1124 The character reading routine sets up a timeout for each block actually read
1125 from the input (which may contain more than one command). We set up a special
1126 signal handler that closes down the session on a timeout. Control does not
1127 return when it runs.
1130 check_sync if TRUE, check synchronization rules if global option is TRUE
1131 buffer_lim maximum to buffer in lower layer
1133 Returns: a code identifying the command (enumerated above)
1137 smtp_read_command(BOOL check_sync, unsigned buffer_lim)
1141 BOOL hadnull = FALSE;
1143 had_command_timeout = 0;
1144 os_non_restarting_signal(SIGALRM, command_timeout_handler);
1146 while ((c = (receive_getc)(buffer_lim)) != '\n' && c != EOF)
1148 if (ptr >= SMTP_CMD_BUFFER_SIZE)
1150 os_non_restarting_signal(SIGALRM, sigalrm_handler);
1158 smtp_cmd_buffer[ptr++] = c;
1161 receive_linecount++; /* For BSMTP errors */
1162 os_non_restarting_signal(SIGALRM, sigalrm_handler);
1164 /* If hit end of file, return pseudo EOF command. Whether we have a
1165 part-line already read doesn't matter, since this is an error state. */
1167 if (c == EOF) return EOF_CMD;
1169 /* Remove any CR and white space at the end of the line, and terminate the
1172 while (ptr > 0 && isspace(smtp_cmd_buffer[ptr-1])) ptr--;
1173 smtp_cmd_buffer[ptr] = 0;
1175 DEBUG(D_receive) debug_printf("SMTP<< %s\n", smtp_cmd_buffer);
1177 /* NULLs are not allowed in SMTP commands */
1179 if (hadnull) return BADCHAR_CMD;
1181 /* Scan command list and return identity, having set the data pointer
1182 to the start of the actual data characters. Check for SMTP synchronization
1185 for (smtp_cmd_list * p = cmd_list; p < cmd_list + nelem(cmd_list); p++)
1187 #ifdef SUPPORT_PROXY
1188 /* Only allow QUIT command if Proxy Protocol parsing failed */
1189 if (proxy_session && f.proxy_session_failed && p->cmd != QUIT_CMD)
1193 && strncmpic(smtp_cmd_buffer, US p->name, p->len) == 0
1194 && ( smtp_cmd_buffer[p->len-1] == ':' /* "mail from:" or "rcpt to:" */
1195 || smtp_cmd_buffer[p->len] == 0
1196 || smtp_cmd_buffer[p->len] == ' '
1199 if ( smtp_inptr < smtp_inend /* Outstanding input */
1200 && p->cmd < sync_cmd_limit /* Command should sync */
1201 && check_sync /* Local flag set */
1202 && smtp_enforce_sync /* Global flag set */
1203 && sender_host_address != NULL /* Not local input */
1204 && !f.sender_host_notsocket /* Really is a socket */
1208 /* The variables $smtp_command and $smtp_command_argument point into the
1209 unmodified input buffer. A copy of the latter is taken for actual
1210 processing, so that it can be chopped up into separate parts if necessary,
1211 for example, when processing a MAIL command options such as SIZE that can
1212 follow the sender address. */
1214 smtp_cmd_argument = smtp_cmd_buffer + p->len;
1215 while (isspace(*smtp_cmd_argument)) smtp_cmd_argument++;
1216 Ustrcpy(smtp_data_buffer, smtp_cmd_argument);
1217 smtp_cmd_data = smtp_data_buffer;
1219 /* Count non-mail commands from those hosts that are controlled in this
1220 way. The default is all hosts. We don't waste effort checking the list
1221 until we get a non-mail command, but then cache the result to save checking
1222 again. If there's a DEFER while checking the host, assume it's in the list.
1224 Note that one instance of RSET, EHLO/HELO, and STARTTLS is allowed at the
1225 start of each incoming message by fiddling with the value in the table. */
1227 if (!p->is_mail_cmd)
1229 if (count_nonmail == TRUE_UNSET) count_nonmail =
1230 verify_check_host(&smtp_accept_max_nonmail_hosts) != FAIL;
1231 if (count_nonmail && ++nonmail_command_count > smtp_accept_max_nonmail)
1232 return TOO_MANY_NONMAIL_CMD;
1235 /* If there is data for a command that does not expect it, generate the
1238 return (p->has_arg || *smtp_cmd_data == 0)? p->cmd : BADARG_CMD;
1242 #ifdef SUPPORT_PROXY
1243 /* Only allow QUIT command if Proxy Protocol parsing failed */
1244 if (proxy_session && f.proxy_session_failed)
1245 return PROXY_FAIL_IGNORE_CMD;
1248 /* Enforce synchronization for unknown commands */
1250 if ( smtp_inptr < smtp_inend /* Outstanding input */
1251 && check_sync /* Local flag set */
1252 && smtp_enforce_sync /* Global flag set */
1253 && sender_host_address /* Not local input */
1254 && !f.sender_host_notsocket /* Really is a socket */
1263 /*************************************************
1264 * Forced closedown of call *
1265 *************************************************/
1267 /* This function is called from log.c when Exim is dying because of a serious
1268 disaster, and also from some other places. If an incoming non-batched SMTP
1269 channel is open, it swallows the rest of the incoming message if in the DATA
1270 phase, sends the reply string, and gives an error to all subsequent commands
1271 except QUIT. The existence of an SMTP call is detected by the non-NULLness of
1275 message SMTP reply string to send, excluding the code
1281 smtp_closedown(uschar * message)
1283 if (!smtp_in || smtp_batched_input) return;
1284 receive_swallow_smtp();
1285 smtp_printf("421 %s\r\n", FALSE, message);
1287 for (;;) switch(smtp_read_command(FALSE, GETC_BUFFER_UNLIMITED))
1293 f.smtp_in_quit = TRUE;
1294 smtp_printf("221 %s closing connection\r\n", FALSE, smtp_active_hostname);
1299 smtp_printf("250 Reset OK\r\n", FALSE);
1303 smtp_printf("421 %s\r\n", FALSE, message);
1311 /*************************************************
1312 * Set up connection info for logging *
1313 *************************************************/
1315 /* This function is called when logging information about an SMTP connection.
1316 It sets up appropriate source information, depending on the type of connection.
1317 If sender_fullhost is NULL, we are at a very early stage of the connection;
1318 just use the IP address.
1321 Returns: a string describing the connection
1325 smtp_get_connection_info(void)
1327 const uschar * hostname = sender_fullhost
1328 ? sender_fullhost : sender_host_address;
1331 return string_sprintf("SMTP connection from %s", hostname);
1333 if (f.sender_host_unknown || f.sender_host_notsocket)
1334 return string_sprintf("SMTP connection from %s", sender_ident);
1337 return string_sprintf("SMTP connection from %s (via inetd)", hostname);
1339 if (LOGGING(incoming_interface) && interface_address)
1340 return string_sprintf("SMTP connection from %s I=[%s]:%d", hostname,
1341 interface_address, interface_port);
1343 return string_sprintf("SMTP connection from %s", hostname);
1349 /* Append TLS-related information to a log line
1352 g String under construction: allocated string to extend, or NULL
1354 Returns: Allocated string or NULL
1357 s_tlslog(gstring * g)
1359 if (LOGGING(tls_cipher) && tls_in.cipher)
1361 g = string_append(g, 2, US" X=", tls_in.cipher);
1362 #ifndef DISABLE_TLS_RESUME
1363 if (LOGGING(tls_resumption) && tls_in.resumption & RESUME_USED)
1364 g = string_catn(g, US"*", 1);
1367 if (LOGGING(tls_certificate_verified) && tls_in.cipher)
1368 g = string_append(g, 2, US" CV=", tls_in.certificate_verified? "yes":"no");
1369 if (LOGGING(tls_peerdn) && tls_in.peerdn)
1370 g = string_append(g, 3, US" DN=\"", string_printing(tls_in.peerdn), US"\"");
1371 if (LOGGING(tls_sni) && tls_in.sni)
1372 g = string_append(g, 2, US" SNI=", string_printing2(tls_in.sni, SP_TAB|SP_SPACE));
1380 s_connhad_log(gstring * g)
1382 const uschar * sep = smtp_connection_had[SMTP_HBUFF_SIZE-1] != SCH_NONE
1383 ? US" C=..." : US" C=";
1385 for (int i = smtp_ch_index; i < SMTP_HBUFF_SIZE; i++)
1386 if (smtp_connection_had[i] != SCH_NONE)
1388 g = string_append(g, 2, sep, smtp_names[smtp_connection_had[i]]);
1391 for (int i = 0; i < smtp_ch_index; i++, sep = US",")
1392 g = string_append(g, 2, sep, smtp_names[smtp_connection_had[i]]);
1397 /*************************************************
1398 * Log lack of MAIL if so configured *
1399 *************************************************/
1401 /* This function is called when an SMTP session ends. If the log selector
1402 smtp_no_mail is set, write a log line giving some details of what has happened
1403 in the SMTP session.
1410 smtp_log_no_mail(void)
1415 if (smtp_mailcmd_count > 0 || !LOGGING(smtp_no_mail))
1418 if (sender_host_authenticated)
1420 g = string_append(g, 2, US" A=", sender_host_authenticated);
1421 if (authenticated_id) g = string_append(g, 2, US":", authenticated_id);
1428 g = s_connhad_log(g);
1430 if (!(s = string_from_gstring(g))) s = US"";
1432 log_write(0, LOG_MAIN, "no MAIL in %sSMTP connection from %s D=%s%s",
1433 f.tcp_in_fastopen ? f.tcp_in_fastopen_data ? US"TFO* " : US"TFO " : US"",
1434 host_and_ident(FALSE), string_timesince(&smtp_connection_start), s);
1438 /* Return list of recent smtp commands */
1443 gstring * list = NULL;
1446 for (int i = smtp_ch_index; i < SMTP_HBUFF_SIZE; i++)
1447 if (smtp_connection_had[i] != SCH_NONE)
1448 list = string_append_listele(list, ',', smtp_names[smtp_connection_had[i]]);
1450 for (int i = 0; i < smtp_ch_index; i++)
1451 list = string_append_listele(list, ',', smtp_names[smtp_connection_had[i]]);
1453 s = string_from_gstring(list);
1454 return s ? s : US"";
1460 /*************************************************
1461 * Check HELO line and set sender_helo_name *
1462 *************************************************/
1464 /* Check the format of a HELO line. The data for HELO/EHLO is supposed to be
1465 the domain name of the sending host, or an ip literal in square brackets. The
1466 argument is placed in sender_helo_name, which is in malloc store, because it
1467 must persist over multiple incoming messages. If helo_accept_junk is set, this
1468 host is permitted to send any old junk (needed for some broken hosts).
1469 Otherwise, helo_allow_chars can be used for rogue characters in general
1470 (typically people want to let in underscores).
1473 s the data portion of the line (already past any white space)
1475 Returns: TRUE or FALSE
1479 check_helo(uschar *s)
1482 uschar *end = s + Ustrlen(s);
1483 BOOL yield = fl.helo_accept_junk;
1485 /* Discard any previous helo name */
1487 sender_helo_name = NULL;
1489 /* Skip tests if junk is permitted. */
1493 /* Allow the new standard form for IPv6 address literals, namely,
1494 [IPv6:....], and because someone is bound to use it, allow an equivalent
1495 IPv4 form. Allow plain addresses as well. */
1502 if (strncmpic(s, US"[IPv6:", 6) == 0)
1503 yield = (string_is_ip_address(s+6, NULL) == 6);
1504 else if (strncmpic(s, US"[IPv4:", 6) == 0)
1505 yield = (string_is_ip_address(s+6, NULL) == 4);
1507 yield = (string_is_ip_address(s+1, NULL) != 0);
1512 /* Non-literals must be alpha, dot, hyphen, plus any non-valid chars
1513 that have been configured (usually underscore - sigh). */
1516 for (yield = TRUE; *s; s++)
1517 if (!isalnum(*s) && *s != '.' && *s != '-' &&
1518 Ustrchr(helo_allow_chars, *s) == NULL)
1524 /* Save argument if OK */
1526 if (yield) sender_helo_name = string_copy_perm(start, TRUE);
1534 /*************************************************
1535 * Extract SMTP command option *
1536 *************************************************/
1538 /* This function picks the next option setting off the end of smtp_cmd_data. It
1539 is called for MAIL FROM and RCPT TO commands, to pick off the optional ESMTP
1540 things that can appear there.
1543 name point this at the name
1544 value point this at the data string
1546 Returns: TRUE if found an option
1550 extract_option(uschar **name, uschar **value)
1554 if (Ustrlen(smtp_cmd_data) <= 0) return FALSE;
1555 v = smtp_cmd_data + Ustrlen(smtp_cmd_data) - 1;
1556 while (v > smtp_cmd_data && isspace(*v)) v--;
1559 while (v > smtp_cmd_data && *v != '=' && !isspace(*v))
1561 /* Take care to not stop at a space embedded in a quoted local-part */
1564 do v--; while (v > smtp_cmd_data && *v != '"');
1565 if (v <= smtp_cmd_data) return FALSE;
1569 if (v <= smtp_cmd_data) return FALSE;
1574 while (n > smtp_cmd_data && isalpha(n[-1])) n--;
1575 /* RFC says SP, but TAB seen in wild and other major MTAs accept it */
1576 if (n <= smtp_cmd_data || !isspace(n[-1])) return FALSE;
1593 /*************************************************
1594 * Reset for new message *
1595 *************************************************/
1597 /* This function is called whenever the SMTP session is reset from
1598 within either of the setup functions; also from the daemon loop.
1600 Argument: the stacking pool storage reset point
1605 smtp_reset(void *reset_point)
1607 recipients_list = NULL;
1608 rcpt_count = rcpt_defer_count = rcpt_fail_count =
1609 raw_recipients_count = recipients_count = recipients_list_max = 0;
1610 message_linecount = 0;
1612 message_body = message_body_end = NULL;
1613 acl_added_headers = NULL;
1614 acl_removed_headers = NULL;
1615 f.queue_only_policy = FALSE;
1616 rcpt_smtp_response = NULL;
1617 fl.rcpt_smtp_response_same = TRUE;
1618 fl.rcpt_in_progress = FALSE;
1619 f.deliver_freeze = FALSE; /* Can be set by ACL */
1620 freeze_tell = freeze_tell_config; /* Can be set by ACL */
1621 fake_response = OK; /* Can be set by ACL */
1622 #ifdef WITH_CONTENT_SCAN
1623 f.no_mbox_unspool = FALSE; /* Can be set by ACL */
1625 f.submission_mode = FALSE; /* Can be set by ACL */
1626 f.suppress_local_fixups = f.suppress_local_fixups_default; /* Can be set by ACL */
1627 f.active_local_from_check = local_from_check; /* Can be set by ACL */
1628 f.active_local_sender_retain = local_sender_retain; /* Can be set by ACL */
1629 sending_ip_address = NULL;
1630 return_path = sender_address = NULL;
1631 deliver_localpart_data = deliver_domain_data =
1632 recipient_data = sender_data = NULL; /* Can be set by ACL */
1633 recipient_verify_failure = NULL;
1634 deliver_localpart_parent = deliver_localpart_orig = NULL;
1635 deliver_domain_parent = deliver_domain_orig = NULL;
1636 callout_address = NULL;
1637 submission_name = NULL; /* Can be set by ACL */
1638 raw_sender = NULL; /* After SMTP rewrite, before qualifying */
1639 sender_address_unrewritten = NULL; /* Set only after verify rewrite */
1640 sender_verified_list = NULL; /* No senders verified */
1641 memset(sender_address_cache, 0, sizeof(sender_address_cache));
1642 memset(sender_domain_cache, 0, sizeof(sender_domain_cache));
1644 authenticated_sender = NULL;
1645 #ifdef EXPERIMENTAL_BRIGHTMAIL
1647 bmi_verdicts = NULL;
1649 dnslist_domain = dnslist_matched = NULL;
1651 spf_header_comment = spf_received = spf_result = spf_smtp_comment = NULL;
1652 spf_result_guessed = FALSE;
1654 #ifndef DISABLE_DKIM
1655 dkim_cur_signer = dkim_signers =
1656 dkim_signing_domain = dkim_signing_selector = dkim_signatures = NULL;
1657 dkim_cur_signer = dkim_signers = dkim_signing_domain = dkim_signing_selector = NULL;
1658 f.dkim_disable_verify = FALSE;
1659 dkim_collect_input = 0;
1660 dkim_verify_overall = dkim_verify_status = dkim_verify_reason = NULL;
1661 dkim_key_length = 0;
1663 #ifdef SUPPORT_DMARC
1664 f.dmarc_has_been_checked = f.dmarc_disable_verify = f.dmarc_enable_forensic = FALSE;
1665 dmarc_domain_policy = dmarc_status = dmarc_status_text =
1666 dmarc_used_domain = NULL;
1668 #ifdef EXPERIMENTAL_ARC
1669 arc_state = arc_state_reason = NULL;
1670 arc_received_instance = 0;
1674 deliver_host = deliver_host_address = NULL; /* Can be set by ACL */
1675 #ifndef DISABLE_PRDR
1676 prdr_requested = FALSE;
1679 message_smtputf8 = FALSE;
1681 #ifdef WITH_CONTENT_SCAN
1684 body_linecount = body_zerocount = 0;
1686 lookup_value = NULL; /* Can be set by ACL */
1687 sender_rate = sender_rate_limit = sender_rate_period = NULL;
1688 ratelimiters_mail = NULL; /* Updated by ratelimit ACL condition */
1689 /* Note that ratelimiters_conn persists across resets. */
1691 /* Reset message ACL variables */
1695 /* Warning log messages are saved in malloc store. They are saved to avoid
1696 repetition in the same message, but it seems right to repeat them for different
1699 while (acl_warn_logged)
1701 string_item *this = acl_warn_logged;
1702 acl_warn_logged = acl_warn_logged->next;
1707 store_reset(reset_point);
1710 return store_mark();
1717 /*************************************************
1718 * Initialize for incoming batched SMTP message *
1719 *************************************************/
1721 /* This function is called from smtp_setup_msg() in the case when
1722 smtp_batched_input is true. This happens when -bS is used to pass a whole batch
1723 of messages in one file with SMTP commands between them. All errors must be
1724 reported by sending a message, and only MAIL FROM, RCPT TO, and DATA are
1725 relevant. After an error on a sender, or an invalid recipient, the remainder
1726 of the message is skipped. The value of received_protocol is already set.
1729 Returns: > 0 message successfully started (reached DATA)
1730 = 0 QUIT read or end of file reached
1731 < 0 should not occur
1735 smtp_setup_batch_msg(void)
1738 rmark reset_point = store_mark();
1740 /* Save the line count at the start of each transaction - single commands
1741 like HELO and RSET count as whole transactions. */
1743 bsmtp_transaction_linecount = receive_linecount;
1745 if ((receive_feof)()) return 0; /* Treat EOF as QUIT */
1747 cancel_cutthrough_connection(TRUE, US"smtp_setup_batch_msg");
1748 reset_point = smtp_reset(reset_point); /* Reset for start of message */
1750 /* Deal with SMTP commands. This loop is exited by setting done to a POSITIVE
1751 value. The values are 2 larger than the required yield of the function. */
1756 uschar *recipient = NULL;
1757 int start, end, sender_domain, recipient_domain;
1759 switch(smtp_read_command(FALSE, GETC_BUFFER_UNLIMITED))
1761 /* The HELO/EHLO commands set sender_address_helo if they have
1762 valid data; otherwise they are ignored, except that they do
1763 a reset of the state. */
1768 check_helo(smtp_cmd_data);
1772 cancel_cutthrough_connection(TRUE, US"RSET received");
1773 reset_point = smtp_reset(reset_point);
1774 bsmtp_transaction_linecount = receive_linecount;
1778 /* The MAIL FROM command requires an address as an operand. All we
1779 do here is to parse it for syntactic correctness. The form "<>" is
1780 a special case which converts into an empty string. The start/end
1781 pointers in the original are not used further for this address, as
1782 it is the canonical extracted address which is all that is kept. */
1785 smtp_mailcmd_count++; /* Count for no-mail log */
1787 /* The function moan_smtp_batch() does not return. */
1788 moan_smtp_batch(smtp_cmd_buffer, "503 Sender already given");
1790 if (smtp_cmd_data[0] == 0)
1791 /* The function moan_smtp_batch() does not return. */
1792 moan_smtp_batch(smtp_cmd_buffer, "501 MAIL FROM must have an address operand");
1794 /* Reset to start of message */
1796 cancel_cutthrough_connection(TRUE, US"MAIL received");
1797 reset_point = smtp_reset(reset_point);
1799 /* Apply SMTP rewrite */
1801 raw_sender = rewrite_existflags & rewrite_smtp
1802 /* deconst ok as smtp_cmd_data was not const */
1803 ? US rewrite_one(smtp_cmd_data, rewrite_smtp|rewrite_smtp_sender, NULL,
1804 FALSE, US"", global_rewrite_rules)
1807 /* Extract the address; the TRUE flag allows <> as valid */
1810 parse_extract_address(raw_sender, &errmess, &start, &end, &sender_domain,
1814 /* The function moan_smtp_batch() does not return. */
1815 moan_smtp_batch(smtp_cmd_buffer, "501 %s", errmess);
1817 sender_address = string_copy(raw_sender);
1819 /* Qualify unqualified sender addresses if permitted to do so. */
1822 && sender_address[0] != 0 && sender_address[0] != '@')
1823 if (f.allow_unqualified_sender)
1825 /* deconst ok as sender_address was not const */
1826 sender_address = US rewrite_address_qualify(sender_address, FALSE);
1827 DEBUG(D_receive) debug_printf("unqualified address %s accepted "
1828 "and rewritten\n", raw_sender);
1830 /* The function moan_smtp_batch() does not return. */
1832 moan_smtp_batch(smtp_cmd_buffer, "501 sender address must contain "
1837 /* The RCPT TO command requires an address as an operand. All we do
1838 here is to parse it for syntactic correctness. There may be any number
1839 of RCPT TO commands, specifying multiple senders. We build them all into
1840 a data structure that is in argc/argv format. The start/end values
1841 given by parse_extract_address are not used, as we keep only the
1842 extracted address. */
1845 if (!sender_address)
1846 /* The function moan_smtp_batch() does not return. */
1847 moan_smtp_batch(smtp_cmd_buffer, "503 No sender yet given");
1849 if (smtp_cmd_data[0] == 0)
1850 /* The function moan_smtp_batch() does not return. */
1851 moan_smtp_batch(smtp_cmd_buffer,
1852 "501 RCPT TO must have an address operand");
1854 /* Check maximum number allowed */
1856 if (recipients_max > 0 && recipients_count + 1 > recipients_max)
1857 /* The function moan_smtp_batch() does not return. */
1858 moan_smtp_batch(smtp_cmd_buffer, "%s too many recipients",
1859 recipients_max_reject? "552": "452");
1861 /* Apply SMTP rewrite, then extract address. Don't allow "<>" as a
1862 recipient address */
1864 recipient = rewrite_existflags & rewrite_smtp
1865 /* deconst ok as smtp_cmd_data was not const */
1866 ? US rewrite_one(smtp_cmd_data, rewrite_smtp, NULL, FALSE, US"",
1867 global_rewrite_rules)
1870 recipient = parse_extract_address(recipient, &errmess, &start, &end,
1871 &recipient_domain, FALSE);
1874 /* The function moan_smtp_batch() does not return. */
1875 moan_smtp_batch(smtp_cmd_buffer, "501 %s", errmess);
1877 /* If the recipient address is unqualified, qualify it if permitted. Then
1878 add it to the list of recipients. */
1880 if (!recipient_domain)
1881 if (f.allow_unqualified_recipient)
1883 DEBUG(D_receive) debug_printf("unqualified address %s accepted\n",
1885 /* deconst ok as recipient was not const */
1886 recipient = US rewrite_address_qualify(recipient, TRUE);
1888 /* The function moan_smtp_batch() does not return. */
1890 moan_smtp_batch(smtp_cmd_buffer,
1891 "501 recipient address must contain a domain");
1893 receive_add_recipient(recipient, -1);
1897 /* The DATA command is legal only if it follows successful MAIL FROM
1898 and RCPT TO commands. This function is complete when a valid DATA
1899 command is encountered. */
1902 if (!sender_address || recipients_count <= 0)
1903 /* The function moan_smtp_batch() does not return. */
1904 if (!sender_address)
1905 moan_smtp_batch(smtp_cmd_buffer,
1906 "503 MAIL FROM:<sender> command must precede DATA");
1908 moan_smtp_batch(smtp_cmd_buffer,
1909 "503 RCPT TO:<recipient> must precede DATA");
1912 done = 3; /* DATA successfully achieved */
1913 message_ended = END_NOTENDED; /* Indicate in middle of message */
1918 /* The VRFY, EXPN, HELP, ETRN, and NOOP commands are ignored. */
1925 bsmtp_transaction_linecount = receive_linecount;
1930 f.smtp_in_quit = TRUE;
1937 /* The function moan_smtp_batch() does not return. */
1938 moan_smtp_batch(smtp_cmd_buffer, "501 Unexpected argument data");
1943 /* The function moan_smtp_batch() does not return. */
1944 moan_smtp_batch(smtp_cmd_buffer, "501 Unexpected NULL in SMTP command");
1949 /* The function moan_smtp_batch() does not return. */
1950 moan_smtp_batch(smtp_cmd_buffer, "500 Command unrecognized");
1955 return done - 2; /* Convert yield values */
1963 smtp_log_tls_fail(const uschar * errstr)
1965 const uschar * conn_info = smtp_get_connection_info();
1967 if (Ustrncmp(conn_info, US"SMTP ", 5) == 0) conn_info += 5;
1968 /* I'd like to get separated H= here, but too hard for now */
1970 log_write(0, LOG_MAIN, "TLS error on %s %s", conn_info, errstr);
1984 socklen_t len = sizeof(is_fastopen);
1986 /* The tinfo TCPOPT_FAST_OPEN bit seems unreliable, and we don't see state
1987 TCP_SYN_RCV (as of 12.1) so no idea about data-use. */
1989 if (getsockopt(fileno(smtp_out), IPPROTO_TCP, TCP_FASTOPEN, &is_fastopen, &len) == 0)
1994 debug_printf("TFO mode connection (TCP_FASTOPEN getsockopt)\n");
1995 f.tcp_in_fastopen = TRUE;
1998 else DEBUG(D_receive)
1999 debug_printf("TCP_INFO getsockopt: %s\n", strerror(errno));
2001 # elif defined(TCP_INFO)
2002 struct tcp_info tinfo;
2003 socklen_t len = sizeof(tinfo);
2005 if (getsockopt(fileno(smtp_out), IPPROTO_TCP, TCP_INFO, &tinfo, &len) == 0)
2006 # ifdef TCPI_OPT_SYN_DATA /* FreeBSD 11,12 do not seem to have this yet */
2007 if (tinfo.tcpi_options & TCPI_OPT_SYN_DATA)
2010 debug_printf("TFO mode connection (ACKd data-on-SYN)\n");
2011 f.tcp_in_fastopen_data = f.tcp_in_fastopen = TRUE;
2015 if (tinfo.tcpi_state == TCP_SYN_RECV) /* Not seen on FreeBSD 12.1 */
2018 debug_printf("TFO mode connection (state TCP_SYN_RECV)\n");
2019 f.tcp_in_fastopen = TRUE;
2021 else DEBUG(D_receive)
2022 debug_printf("TCP_INFO getsockopt: %s\n", strerror(errno));
2029 log_connect_tls_drop(const uschar * what, const uschar * log_msg)
2031 gstring * g = s_tlslog(NULL);
2032 uschar * tls = string_from_gstring(g);
2034 log_write(L_connection_reject,
2035 log_reject_target, "%s%s%s dropped by %s%s%s",
2036 LOGGING(dnssec) && sender_host_dnssec ? US" DS" : US"",
2037 host_and_ident(TRUE),
2040 log_msg ? US": " : US"", log_msg);
2044 /*************************************************
2045 * Start an SMTP session *
2046 *************************************************/
2048 /* This function is called at the start of an SMTP session. Thereafter,
2049 smtp_setup_msg() is called to initiate each separate message. This
2050 function does host-specific testing, and outputs the banner line.
2053 Returns: FALSE if the session can not continue; something has
2054 gone wrong, or the connection to the host is blocked
2058 smtp_start_session(void)
2061 uschar *user_msg, *log_msg;
2066 gettimeofday(&smtp_connection_start, NULL);
2067 for (smtp_ch_index = 0; smtp_ch_index < SMTP_HBUFF_SIZE; smtp_ch_index++)
2068 smtp_connection_had[smtp_ch_index] = SCH_NONE;
2071 /* Default values for certain variables */
2073 fl.helo_seen = fl.esmtp = fl.helo_accept_junk = FALSE;
2074 smtp_mailcmd_count = 0;
2075 count_nonmail = TRUE_UNSET;
2076 synprot_error_count = unknown_command_count = nonmail_command_count = 0;
2077 smtp_delay_mail = smtp_rlm_base;
2078 fl.auth_advertised = FALSE;
2079 f.smtp_in_pipelining_advertised = f.smtp_in_pipelining_used = FALSE;
2080 f.pipelining_enable = TRUE;
2081 sync_cmd_limit = NON_SYNC_CMD_NON_PIPELINING;
2082 fl.smtp_exit_function_called = FALSE; /* For avoiding loop in not-quit exit */
2084 /* If receiving by -bs from a trusted user, or testing with -bh, we allow
2085 authentication settings from -oMaa to remain in force. */
2087 if (!host_checking && !f.sender_host_notsocket)
2088 sender_host_auth_pubname = sender_host_authenticated = NULL;
2089 authenticated_by = NULL;
2092 tls_in.ver = tls_in.cipher = tls_in.peerdn = NULL;
2093 tls_in.ourcert = tls_in.peercert = NULL;
2095 tls_in.ocsp = OCSP_NOT_REQ;
2096 fl.tls_advertised = FALSE;
2098 fl.dsn_advertised = FALSE;
2100 fl.smtputf8_advertised = FALSE;
2103 /* Reset ACL connection variables */
2107 /* Allow for trailing 0 in the command and data buffers. Tainted. */
2109 smtp_cmd_buffer = store_get_perm(2*SMTP_CMD_BUFFER_SIZE + 2, GET_TAINTED);
2111 smtp_cmd_buffer[0] = 0;
2112 smtp_data_buffer = smtp_cmd_buffer + SMTP_CMD_BUFFER_SIZE + 1;
2114 /* For batched input, the protocol setting can be overridden from the
2115 command line by a trusted caller. */
2117 if (smtp_batched_input)
2119 if (!received_protocol) received_protocol = US"local-bsmtp";
2122 /* For non-batched SMTP input, the protocol setting is forced here. It will be
2123 reset later if any of EHLO/AUTH/STARTTLS are received. */
2127 (sender_host_address ? protocols : protocols_local) [pnormal];
2129 /* Set up the buffer for inputting using direct read() calls, and arrange to
2130 call the local functions instead of the standard C ones. */
2134 receive_getc = smtp_getc;
2135 receive_getbuf = smtp_getbuf;
2136 receive_get_cache = smtp_get_cache;
2137 receive_hasc = smtp_hasc;
2138 receive_ungetc = smtp_ungetc;
2139 receive_feof = smtp_feof;
2140 receive_ferror = smtp_ferror;
2141 lwr_receive_getc = NULL;
2142 lwr_receive_getbuf = NULL;
2143 lwr_receive_hasc = NULL;
2144 lwr_receive_ungetc = NULL;
2146 /* Set up the message size limit; this may be host-specific */
2148 thismessage_size_limit = expand_string_integer(message_size_limit, TRUE);
2149 if (expand_string_message)
2151 if (thismessage_size_limit == -1)
2152 log_write(0, LOG_MAIN|LOG_PANIC, "unable to expand message_size_limit: "
2153 "%s", expand_string_message);
2155 log_write(0, LOG_MAIN|LOG_PANIC, "invalid message_size_limit: "
2156 "%s", expand_string_message);
2157 smtp_closedown(US"Temporary local problem - please try later");
2161 /* When a message is input locally via the -bs or -bS options, sender_host_
2162 unknown is set unless -oMa was used to force an IP address, in which case it
2163 is checked like a real remote connection. When -bs is used from inetd, this
2164 flag is not set, causing the sending host to be checked. The code that deals
2165 with IP source routing (if configured) is never required for -bs or -bS and
2166 the flag sender_host_notsocket is used to suppress it.
2168 If smtp_accept_max and smtp_accept_reserve are set, keep some connections in
2169 reserve for certain hosts and/or networks. */
2171 if (!f.sender_host_unknown)
2174 BOOL reserved_host = FALSE;
2176 /* Look up IP options (source routing info) on the socket if this is not an
2177 -oMa "host", and if any are found, log them and drop the connection.
2179 Linux (and others now, see below) is different to everyone else, so there
2180 has to be some conditional compilation here. Versions of Linux before 2.1.15
2181 used a structure whose name was "options". Somebody finally realized that
2182 this name was silly, and it got changed to "ip_options". I use the
2183 newer name here, but there is a fudge in the script that sets up os.h
2184 to define a macro in older Linux systems.
2186 Sigh. Linux is a fast-moving target. Another generation of Linux uses
2187 glibc 2, which has chosen ip_opts for the structure name. This is now
2188 really a glibc thing rather than a Linux thing, so the condition name
2189 has been changed to reflect this. It is relevant also to GNU/Hurd.
2191 Mac OS 10.x (Darwin) is like the later glibc versions, but without the
2192 setting of the __GLIBC__ macro, so we can't detect it automatically. There's
2193 a special macro defined in the os.h file.
2195 Some DGUX versions on older hardware appear not to support IP options at
2196 all, so there is now a general macro which can be set to cut out this
2199 How to do this properly in IPv6 is not yet known. */
2201 #if !HAVE_IPV6 && !defined(NO_IP_OPTIONS)
2203 # ifdef GLIBC_IP_OPTIONS
2204 # if (!defined __GLIBC__) || (__GLIBC__ < 2)
2209 # elif defined DARWIN_IP_OPTIONS
2215 if (!host_checking && !f.sender_host_notsocket)
2218 EXIM_SOCKLEN_T optlen = sizeof(struct ip_options) + MAX_IPOPTLEN;
2219 struct ip_options *ipopt = store_get(optlen, GET_UNTAINTED);
2220 # elif OPTSTYLE == 2
2221 struct ip_opts ipoptblock;
2222 struct ip_opts *ipopt = &ipoptblock;
2223 EXIM_SOCKLEN_T optlen = sizeof(ipoptblock);
2225 struct ipoption ipoptblock;
2226 struct ipoption *ipopt = &ipoptblock;
2227 EXIM_SOCKLEN_T optlen = sizeof(ipoptblock);
2230 /* Occasional genuine failures of getsockopt() have been seen - for
2231 example, "reset by peer". Therefore, just log and give up on this
2232 call, unless the error is ENOPROTOOPT. This error is given by systems
2233 that have the interfaces but not the mechanism - e.g. GNU/Hurd at the time
2234 of writing. So for that error, carry on - we just can't do an IP options
2237 DEBUG(D_receive) debug_printf("checking for IP options\n");
2239 if (getsockopt(fileno(smtp_out), IPPROTO_IP, IP_OPTIONS, US (ipopt),
2242 if (errno != ENOPROTOOPT)
2244 log_write(0, LOG_MAIN, "getsockopt() failed from %s: %s",
2245 host_and_ident(FALSE), strerror(errno));
2246 smtp_printf("451 SMTP service not available\r\n", FALSE);
2251 /* Deal with any IP options that are set. On the systems I have looked at,
2252 the value of MAX_IPOPTLEN has been 40, meaning that there should never be
2253 more logging data than will fit in big_buffer. Nevertheless, after somebody
2254 questioned this code, I've added in some paranoid checking. */
2256 else if (optlen > 0)
2258 uschar * p = big_buffer;
2259 uschar * pend = big_buffer + big_buffer_size;
2262 struct in_addr addr;
2265 uschar * optstart = US (ipopt->__data);
2266 # elif OPTSTYLE == 2
2267 uschar * optstart = US (ipopt->ip_opts);
2269 uschar * optstart = US (ipopt->ipopt_list);
2272 DEBUG(D_receive) debug_printf("IP options exist\n");
2274 Ustrcpy(p, "IP options on incoming call:");
2277 for (uschar * opt = optstart; opt && opt < US (ipopt) + optlen; )
2292 string_format(p, pend-p, " %s [@%s",
2293 (*opt == IPOPT_SSRR)? "SSRR" : "LSRR",
2294 inet_ntoa(*((struct in_addr *)(&(ipopt->faddr)))))
2295 # elif OPTSTYLE == 2
2296 string_format(p, pend-p, " %s [@%s",
2297 (*opt == IPOPT_SSRR)? "SSRR" : "LSRR",
2298 inet_ntoa(ipopt->ip_dst))
2300 string_format(p, pend-p, " %s [@%s",
2301 (*opt == IPOPT_SSRR)? "SSRR" : "LSRR",
2302 inet_ntoa(ipopt->ipopt_dst))
2311 optcount = (opt[1] - 3) / sizeof(struct in_addr);
2313 while (optcount-- > 0)
2315 memcpy(&addr, adptr, sizeof(addr));
2316 if (!string_format(p, pend - p - 1, "%s%s",
2317 (optcount == 0)? ":" : "@", inet_ntoa(addr)))
2323 adptr += sizeof(struct in_addr);
2331 if (pend - p < 4 + 3*opt[1]) { opt = NULL; break; }
2334 for (int i = 0; i < opt[1]; i++)
2335 p += sprintf(CS p, "%2.2x ", opt[i]);
2343 log_write(0, LOG_MAIN, "%s", big_buffer);
2345 /* Refuse any call with IP options. This is what tcpwrappers 7.5 does. */
2347 log_write(0, LOG_MAIN|LOG_REJECT,
2348 "connection from %s refused (IP options)", host_and_ident(FALSE));
2350 smtp_printf("554 SMTP service not available\r\n", FALSE);
2354 /* Length of options = 0 => there are no options */
2356 else DEBUG(D_receive) debug_printf("no IP options found\n");
2358 #endif /* HAVE_IPV6 && !defined(NO_IP_OPTIONS) */
2360 /* Set keep-alive in socket options. The option is on by default. This
2361 setting is an attempt to get rid of some hanging connections that stick in
2362 read() when the remote end (usually a dialup) goes away. */
2364 if (smtp_accept_keepalive && !f.sender_host_notsocket)
2365 ip_keepalive(fileno(smtp_out), sender_host_address, FALSE);
2367 /* If the current host matches host_lookup, set the name by doing a
2368 reverse lookup. On failure, sender_host_name will be NULL and
2369 host_lookup_failed will be TRUE. This may or may not be serious - optional
2372 if (verify_check_host(&host_lookup) == OK)
2374 (void)host_name_lookup();
2375 host_build_sender_fullhost();
2378 /* Delay this until we have the full name, if it is looked up. */
2380 set_process_info("handling incoming connection from %s",
2381 host_and_ident(FALSE));
2383 /* Expand smtp_receive_timeout, if needed */
2385 if (smtp_receive_timeout_s)
2388 if ( !(exp = expand_string(smtp_receive_timeout_s))
2390 || (smtp_receive_timeout = readconf_readtime(exp, 0, FALSE)) < 0
2392 log_write(0, LOG_MAIN|LOG_PANIC,
2393 "bad value for smtp_receive_timeout: '%s'", exp ? exp : US"");
2396 /* Test for explicit connection rejection */
2398 if (verify_check_host(&host_reject_connection) == OK)
2400 log_write(L_connection_reject, LOG_MAIN|LOG_REJECT, "refused connection "
2401 "from %s (host_reject_connection)", host_and_ident(FALSE));
2403 if (!tls_in.on_connect)
2405 smtp_printf("554 SMTP service not available\r\n", FALSE);
2409 /* Test with TCP Wrappers if so configured. There is a problem in that
2410 hosts_ctl() returns 0 (deny) under a number of system failure circumstances,
2411 such as disks dying. In these cases, it is desirable to reject with a 4xx
2412 error instead of a 5xx error. There isn't a "right" way to detect such
2413 problems. The following kludge is used: errno is zeroed before calling
2414 hosts_ctl(). If the result is "reject", a 5xx error is given only if the
2415 value of errno is 0 or ENOENT (which happens if /etc/hosts.{allow,deny} does
2418 #ifdef USE_TCP_WRAPPERS
2420 if (!(tcp_wrappers_name = expand_string(tcp_wrappers_daemon_name)))
2421 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "Expansion of \"%s\" "
2422 "(tcp_wrappers_name) failed: %s", string_printing(tcp_wrappers_name),
2423 expand_string_message);
2425 if (!hosts_ctl(tcp_wrappers_name,
2426 sender_host_name ? CS sender_host_name : STRING_UNKNOWN,
2427 sender_host_address ? CS sender_host_address : STRING_UNKNOWN,
2428 sender_ident ? CS sender_ident : STRING_UNKNOWN))
2430 if (errno == 0 || errno == ENOENT)
2432 HDEBUG(D_receive) debug_printf("tcp wrappers rejection\n");
2433 log_write(L_connection_reject,
2434 LOG_MAIN|LOG_REJECT, "refused connection from %s "
2435 "(tcp wrappers)", host_and_ident(FALSE));
2436 smtp_printf("554 SMTP service not available\r\n", FALSE);
2440 int save_errno = errno;
2441 HDEBUG(D_receive) debug_printf("tcp wrappers rejected with unexpected "
2442 "errno value %d\n", save_errno);
2443 log_write(L_connection_reject,
2444 LOG_MAIN|LOG_REJECT, "temporarily refused connection from %s "
2445 "(tcp wrappers errno=%d)", host_and_ident(FALSE), save_errno);
2446 smtp_printf("451 Temporary local problem - please try later\r\n", FALSE);
2452 /* Check for reserved slots. The value of smtp_accept_count has already been
2453 incremented to include this process. */
2455 if (smtp_accept_max > 0 &&
2456 smtp_accept_count > smtp_accept_max - smtp_accept_reserve)
2458 if ((rc = verify_check_host(&smtp_reserve_hosts)) != OK)
2460 log_write(L_connection_reject,
2461 LOG_MAIN, "temporarily refused connection from %s: not in "
2462 "reserve list: connected=%d max=%d reserve=%d%s",
2463 host_and_ident(FALSE), smtp_accept_count - 1, smtp_accept_max,
2464 smtp_accept_reserve, (rc == DEFER)? " (lookup deferred)" : "");
2465 smtp_printf("421 %s: Too many concurrent SMTP connections; "
2466 "please try again later\r\n", FALSE, smtp_active_hostname);
2469 reserved_host = TRUE;
2472 /* If a load level above which only messages from reserved hosts are
2473 accepted is set, check the load. For incoming calls via the daemon, the
2474 check is done in the superior process if there are no reserved hosts, to
2475 save a fork. In all cases, the load average will already be available
2476 in a global variable at this point. */
2478 if (smtp_load_reserve >= 0 &&
2479 load_average > smtp_load_reserve &&
2481 verify_check_host(&smtp_reserve_hosts) != OK)
2483 log_write(L_connection_reject,
2484 LOG_MAIN, "temporarily refused connection from %s: not in "
2485 "reserve list and load average = %.2f", host_and_ident(FALSE),
2486 (double)load_average/1000.0);
2487 smtp_printf("421 %s: Too much load; please try again later\r\n", FALSE,
2488 smtp_active_hostname);
2492 /* Determine whether unqualified senders or recipients are permitted
2493 for this host. Unfortunately, we have to do this every time, in order to
2494 set the flags so that they can be inspected when considering qualifying
2495 addresses in the headers. For a site that permits no qualification, this
2496 won't take long, however. */
2498 f.allow_unqualified_sender =
2499 verify_check_host(&sender_unqualified_hosts) == OK;
2501 f.allow_unqualified_recipient =
2502 verify_check_host(&recipient_unqualified_hosts) == OK;
2504 /* Determine whether HELO/EHLO is required for this host. The requirement
2505 can be hard or soft. */
2507 fl.helo_verify_required = verify_check_host(&helo_verify_hosts) == OK;
2508 if (!fl.helo_verify_required)
2509 fl.helo_verify = verify_check_host(&helo_try_verify_hosts) == OK;
2511 /* Determine whether this hosts is permitted to send syntactic junk
2512 after a HELO or EHLO command. */
2514 fl.helo_accept_junk = verify_check_host(&helo_accept_junk_hosts) == OK;
2517 /* For batch SMTP input we are now done. */
2519 if (smtp_batched_input) return TRUE;
2521 #if defined(SUPPORT_PROXY) || defined(SUPPORT_SOCKS) || defined(EXPERIMETAL_XCLIENT)
2522 proxy_session = FALSE;
2525 #ifdef SUPPORT_PROXY
2526 /* If valid Proxy Protocol source is connecting, set up session.
2527 Failure will not allow any SMTP function other than QUIT. */
2529 f.proxy_session_failed = FALSE;
2530 if (proxy_protocol_host())
2532 os_non_restarting_signal(SIGALRM, command_timeout_handler);
2533 proxy_protocol_setup();
2537 /* Run the connect ACL if it exists */
2540 if (acl_smtp_connect)
2543 if ((rc = acl_check(ACL_WHERE_CONNECT, NULL, acl_smtp_connect, &user_msg,
2547 if (tls_in.on_connect)
2548 log_connect_tls_drop(US"'connect' ACL", log_msg);
2551 (void) smtp_handle_acl_fail(ACL_WHERE_CONNECT, rc, user_msg, log_msg);
2556 /* Start up TLS if tls_on_connect is set. This is for supporting the legacy
2557 smtps port for use with older style SSL MTAs. */
2560 if (tls_in.on_connect)
2562 if (tls_server_start(&user_msg) != OK)
2563 return smtp_log_tls_fail(user_msg);
2564 cmd_list[CL_TLAU].is_mail_cmd = TRUE;
2568 /* Output the initial message for a two-way SMTP connection. It may contain
2569 newlines, which then cause a multi-line response to be given. */
2571 code = US"220"; /* Default status code */
2572 esc = US""; /* Default extended status code */
2573 esclen = 0; /* Length of esc */
2579 smtp_message_code(&code, &codelen, &s, NULL, TRUE);
2583 esclen = codelen - 4;
2586 else if (!(s = expand_string(smtp_banner)))
2588 log_write(0, f.expand_string_forcedfail ? LOG_MAIN : LOG_MAIN|LOG_PANIC_DIE,
2589 "Expansion of \"%s\" (smtp_banner) failed: %s",
2590 smtp_banner, expand_string_message);
2591 /* for force-fail */
2593 if (tls_in.on_connect) tls_close(NULL, TLS_SHUTDOWN_WAIT);
2598 /* Remove any terminating newlines; might as well remove trailing space too */
2601 while (p > s && isspace(p[-1])) p--;
2602 s = string_copyn(s, p-s);
2604 /* It seems that CC:Mail is braindead, and assumes that the greeting message
2605 is all contained in a single IP packet. The original code wrote out the
2606 greeting using several calls to fprint/fputc, and on busy servers this could
2607 cause it to be split over more than one packet - which caused CC:Mail to fall
2608 over when it got the second part of the greeting after sending its first
2609 command. Sigh. To try to avoid this, build the complete greeting message
2610 first, and output it in one fell swoop. This gives a better chance of it
2611 ending up as a single packet. */
2613 ss = string_get(256);
2616 do /* At least once, in case we have an empty string */
2619 uschar *linebreak = Ustrchr(p, '\n');
2620 ss = string_catn(ss, code, 3);
2624 ss = string_catn(ss, US" ", 1);
2628 len = linebreak - p;
2629 ss = string_catn(ss, US"-", 1);
2631 ss = string_catn(ss, esc, esclen);
2632 ss = string_catn(ss, p, len);
2633 ss = string_catn(ss, US"\r\n", 2);
2639 /* Before we write the banner, check that there is no input pending, unless
2640 this synchronisation check is disabled. */
2642 #ifndef DISABLE_PIPE_CONNECT
2643 fl.pipe_connect_acceptable =
2644 sender_host_address && verify_check_host(&pipe_connect_advertise_hosts) == OK;
2647 if (fl.pipe_connect_acceptable)
2648 f.smtp_in_early_pipe_used = TRUE;
2654 unsigned n = smtp_inend - smtp_inptr;
2655 if (n > 128) n = 128;
2657 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP protocol "
2658 "synchronization error (input sent without waiting for greeting): "
2659 "rejected connection from %s input=\"%s\"", host_and_ident(TRUE),
2660 string_printing(string_copyn(smtp_inptr, n)));
2661 smtp_printf("554 SMTP synchronization error\r\n", FALSE);
2665 /* Now output the banner */
2666 /*XXX the ehlo-resp code does its own tls/nontls bit. Maybe subroutine that? */
2669 #ifndef DISABLE_PIPE_CONNECT
2670 fl.pipe_connect_acceptable && pipeline_connect_sends(),
2674 string_from_gstring(ss));
2676 /* Attempt to see if we sent the banner before the last ACK of the 3-way
2677 handshake arrived. If so we must have managed a TFO. */
2680 if (sender_host_address && !f.sender_host_notsocket) tfo_in_check();
2690 /*************************************************
2691 * Handle SMTP syntax and protocol errors *
2692 *************************************************/
2694 /* Write to the log for SMTP syntax errors in incoming commands, if configured
2695 to do so. Then transmit the error response. The return value depends on the
2696 number of syntax and protocol errors in this SMTP session.
2699 type error type, given as a log flag bit
2700 code response code; <= 0 means don't send a response
2701 data data to reflect in the response (can be NULL)
2702 errmess the error message
2704 Returns: -1 limit of syntax/protocol errors NOT exceeded
2705 +1 limit of syntax/protocol errors IS exceeded
2707 These values fit in with the values of the "done" variable in the main
2708 processing loop in smtp_setup_msg(). */
2711 synprot_error(int type, int code, uschar *data, uschar *errmess)
2715 log_write(type, LOG_MAIN, "SMTP %s error in \"%s\" %s %s",
2716 type == L_smtp_syntax_error ? "syntax" : "protocol",
2717 string_printing(smtp_cmd_buffer), host_and_ident(TRUE), errmess);
2719 if (++synprot_error_count > smtp_max_synprot_errors)
2722 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
2723 "syntax or protocol errors (last command was \"%s\", %s)",
2724 host_and_ident(FALSE), string_printing(smtp_cmd_buffer),
2725 string_from_gstring(s_connhad_log(NULL))
2731 smtp_printf("%d%c%s%s%s\r\n", FALSE, code, yield == 1 ? '-' : ' ',
2732 data ? data : US"", data ? US": " : US"", errmess);
2734 smtp_printf("%d Too many syntax or protocol errors\r\n", FALSE, code);
2743 /*************************************************
2744 * Send SMTP response, possibly multiline *
2745 *************************************************/
2747 /* There are, it seems, broken clients out there that cannot handle multiline
2748 responses. If no_multiline_responses is TRUE (it can be set from an ACL), we
2749 output nothing for non-final calls, and only the first line for anything else.
2752 code SMTP code, may involve extended status codes
2753 codelen length of smtp code; if > 4 there's an ESC
2754 final FALSE if the last line isn't the final line
2755 msg message text, possibly containing newlines
2761 smtp_respond(uschar* code, int codelen, BOOL final, uschar *msg)
2766 if (!final && f.no_multiline_responses) return;
2771 esclen = codelen - 4;
2774 /* If this is the first output for a (non-batch) RCPT command, see if all RCPTs
2775 have had the same. Note: this code is also present in smtp_printf(). It would
2776 be tidier to have it only in one place, but when it was added, it was easier to
2777 do it that way, so as not to have to mess with the code for the RCPT command,
2778 which sometimes uses smtp_printf() and sometimes smtp_respond(). */
2780 if (fl.rcpt_in_progress)
2782 if (!rcpt_smtp_response)
2783 rcpt_smtp_response = string_copy(msg);
2784 else if (fl.rcpt_smtp_response_same &&
2785 Ustrcmp(rcpt_smtp_response, msg) != 0)
2786 fl.rcpt_smtp_response_same = FALSE;
2787 fl.rcpt_in_progress = FALSE;
2790 /* Now output the message, splitting it up into multiple lines if necessary.
2791 We only handle pipelining these responses as far as nonfinal/final groups,
2792 not the whole MAIL/RCPT/DATA response set. */
2796 uschar *nl = Ustrchr(msg, '\n');
2799 smtp_printf("%.3s%c%.*s%s\r\n", !final, code, final ? ' ':'-', esclen, esc, msg);
2802 else if (nl[1] == 0 || f.no_multiline_responses)
2804 smtp_printf("%.3s%c%.*s%.*s\r\n", !final, code, final ? ' ':'-', esclen, esc,
2805 (int)(nl - msg), msg);
2810 smtp_printf("%.3s-%.*s%.*s\r\n", TRUE, code, esclen, esc, (int)(nl - msg), msg);
2812 Uskip_whitespace(&msg);
2820 /*************************************************
2821 * Parse user SMTP message *
2822 *************************************************/
2824 /* This function allows for user messages overriding the response code details
2825 by providing a suitable response code string at the start of the message
2826 user_msg. Check the message for starting with a response code and optionally an
2827 extended status code. If found, check that the first digit is valid, and if so,
2828 change the code pointer and length to use the replacement. An invalid code
2829 causes a panic log; in this case, if the log messages is the same as the user
2830 message, we must also adjust the value of the log message to show the code that
2831 is actually going to be used (the original one).
2833 This function is global because it is called from receive.c as well as within
2836 Note that the code length returned includes the terminating whitespace
2837 character, which is always included in the regex match.
2840 code SMTP code, may involve extended status codes
2841 codelen length of smtp code; if > 4 there's an ESC
2843 log_msg optional log message, to be adjusted with the new SMTP code
2844 check_valid if true, verify the response code
2850 smtp_message_code(uschar **code, int *codelen, uschar **msg, uschar **log_msg,
2856 if (!msg || !*msg || !regex_match(regex_smtp_code, *msg, -1, &match))
2859 len = Ustrlen(match);
2860 if (check_valid && (*msg)[0] != (*code)[0])
2862 log_write(0, LOG_MAIN|LOG_PANIC, "configured error code starts with "
2863 "incorrect digit (expected %c) in \"%s\"", (*code)[0], *msg);
2864 if (log_msg && *log_msg == *msg)
2865 *log_msg = string_sprintf("%s %s", *code, *log_msg + len);
2870 *codelen = len; /* Includes final space */
2872 *msg += len; /* Chop the code off the message */
2879 /*************************************************
2880 * Handle an ACL failure *
2881 *************************************************/
2883 /* This function is called when acl_check() fails. As well as calls from within
2884 this module, it is called from receive.c for an ACL after DATA. It sorts out
2885 logging the incident, and sends the error response. A message containing
2886 newlines is turned into a multiline SMTP response, but for logging, only the
2889 There's a table of default permanent failure response codes to use in
2890 globals.c, along with the table of names. VFRY is special. Despite RFC1123 it
2891 defaults disabled in Exim. However, discussion in connection with RFC 821bis
2892 (aka RFC 2821) has concluded that the response should be 252 in the disabled
2893 state, because there are broken clients that try VRFY before RCPT. A 5xx
2894 response should be given only when the address is positively known to be
2895 undeliverable. Sigh. We return 252 if there is no VRFY ACL or it provides
2896 no explicit code, but if there is one we let it know best.
2897 Also, for ETRN, 458 is given on refusal, and for AUTH, 503.
2899 From Exim 4.63, it is possible to override the response code details by
2900 providing a suitable response code string at the start of the message provided
2901 in user_msg. The code's first digit is checked for validity.
2904 where where the ACL was called from
2906 user_msg a message that can be included in an SMTP response
2907 log_msg a message for logging
2909 Returns: 0 in most cases
2910 2 if the failure code was FAIL_DROP, in which case the
2911 SMTP connection should be dropped (this value fits with the
2912 "done" variable in smtp_setup_msg() below)
2916 smtp_handle_acl_fail(int where, int rc, uschar *user_msg, uschar *log_msg)
2918 BOOL drop = rc == FAIL_DROP;
2922 uschar *sender_info = US"";
2925 if (drop) rc = FAIL;
2927 /* Set the default SMTP code, and allow a user message to change it. */
2929 smtp_code = rc == FAIL ? acl_wherecodes[where] : US"451";
2930 smtp_message_code(&smtp_code, &codelen, &user_msg, &log_msg,
2931 where != ACL_WHERE_VRFY);
2933 /* We used to have sender_address here; however, there was a bug that was not
2934 updating sender_address after a rewrite during a verify. When this bug was
2935 fixed, sender_address at this point became the rewritten address. I'm not sure
2936 this is what should be logged, so I've changed to logging the unrewritten
2937 address to retain backward compatibility. */
2941 #ifdef WITH_CONTENT_SCAN
2942 case ACL_WHERE_MIME: what = US"during MIME ACL checks"; break;
2944 case ACL_WHERE_PREDATA: what = US"DATA"; break;
2945 case ACL_WHERE_DATA: what = US"after DATA"; break;
2946 #ifndef DISABLE_PRDR
2947 case ACL_WHERE_PRDR: what = US"after DATA PRDR"; break;
2951 uschar * place = smtp_cmd_data ? smtp_cmd_data : US"in \"connect\" ACL";
2954 if (where == ACL_WHERE_AUTH) /* avoid logging auth creds */
2957 for (s = smtp_cmd_data; *s && !isspace(*s); ) s++;
2958 lim = s - smtp_cmd_data; /* atop after method */
2960 what = string_sprintf("%s %.*s", acl_wherenames[where], lim, place);
2965 case ACL_WHERE_RCPT:
2966 case ACL_WHERE_DATA:
2967 #ifdef WITH_CONTENT_SCAN
2968 case ACL_WHERE_MIME:
2970 sender_info = string_sprintf("F=<%s>%s%s%s%s ",
2971 sender_address_unrewritten ? sender_address_unrewritten : sender_address,
2972 sender_host_authenticated ? US" A=" : US"",
2973 sender_host_authenticated ? sender_host_authenticated : US"",
2974 sender_host_authenticated && authenticated_id ? US":" : US"",
2975 sender_host_authenticated && authenticated_id ? authenticated_id : US""
2980 /* If there's been a sender verification failure with a specific message, and
2981 we have not sent a response about it yet, do so now, as a preliminary line for
2982 failures, but not defers. However, always log it for defer, and log it for fail
2983 unless the sender_verify_fail log selector has been turned off. */
2985 if (sender_verified_failed &&
2986 !testflag(sender_verified_failed, af_sverify_told))
2988 BOOL save_rcpt_in_progress = fl.rcpt_in_progress;
2989 fl.rcpt_in_progress = FALSE; /* So as not to treat these as the error */
2991 setflag(sender_verified_failed, af_sverify_told);
2993 if (rc != FAIL || LOGGING(sender_verify_fail))
2994 log_write(0, LOG_MAIN|LOG_REJECT, "%s sender verify %s for <%s>%s",
2995 host_and_ident(TRUE),
2996 ((sender_verified_failed->special_action & 255) == DEFER)? "defer":"fail",
2997 sender_verified_failed->address,
2998 (sender_verified_failed->message == NULL)? US"" :
2999 string_sprintf(": %s", sender_verified_failed->message));
3001 if (rc == FAIL && sender_verified_failed->user_message)
3002 smtp_respond(smtp_code, codelen, FALSE, string_sprintf(
3003 testflag(sender_verified_failed, af_verify_pmfail)?
3004 "Postmaster verification failed while checking <%s>\n%s\n"
3005 "Several RFCs state that you are required to have a postmaster\n"
3006 "mailbox for each mail domain. This host does not accept mail\n"
3007 "from domains whose servers reject the postmaster address."
3009 testflag(sender_verified_failed, af_verify_nsfail)?
3010 "Callback setup failed while verifying <%s>\n%s\n"
3011 "The initial connection, or a HELO or MAIL FROM:<> command was\n"
3012 "rejected. Refusing MAIL FROM:<> does not help fight spam, disregards\n"
3013 "RFC requirements, and stops you from receiving standard bounce\n"
3014 "messages. This host does not accept mail from domains whose servers\n"
3017 "Verification failed for <%s>\n%s",
3018 sender_verified_failed->address,
3019 sender_verified_failed->user_message));
3021 fl.rcpt_in_progress = save_rcpt_in_progress;
3024 /* Sort out text for logging */
3026 log_msg = log_msg ? string_sprintf(": %s", log_msg) : US"";
3027 if ((lognl = Ustrchr(log_msg, '\n'))) *lognl = 0;
3029 /* Send permanent failure response to the command, but the code used isn't
3030 always a 5xx one - see comments at the start of this function. If the original
3031 rc was FAIL_DROP we drop the connection and yield 2. */
3034 smtp_respond(smtp_code, codelen, TRUE,
3035 user_msg ? user_msg : US"Administrative prohibition");
3037 /* Send temporary failure response to the command. Don't give any details,
3038 unless acl_temp_details is set. This is TRUE for a callout defer, a "defer"
3039 verb, and for a header verify when smtp_return_error_details is set.
3041 This conditional logic is all somewhat of a mess because of the odd
3042 interactions between temp_details and return_error_details. One day it should
3043 be re-implemented in a tidier fashion. */
3046 if (f.acl_temp_details && user_msg)
3048 if ( smtp_return_error_details
3049 && sender_verified_failed
3050 && sender_verified_failed->message
3052 smtp_respond(smtp_code, codelen, FALSE, sender_verified_failed->message);
3054 smtp_respond(smtp_code, codelen, TRUE, user_msg);
3057 smtp_respond(smtp_code, codelen, TRUE,
3058 US"Temporary local problem - please try later");
3060 /* Log the incident to the logs that are specified by log_reject_target
3061 (default main, reject). This can be empty to suppress logging of rejections. If
3062 the connection is not forcibly to be dropped, return 0. Otherwise, log why it
3063 is closing if required and return 2. */
3065 if (log_reject_target != 0)
3068 gstring * g = s_tlslog(NULL);
3069 uschar * tls = string_from_gstring(g);
3070 if (!tls) tls = US"";
3072 uschar * tls = US"";
3074 log_write(where == ACL_WHERE_CONNECT ? L_connection_reject : 0,
3075 log_reject_target, "%s%s%s %s%srejected %s%s",
3076 LOGGING(dnssec) && sender_host_dnssec ? US" DS" : US"",
3077 host_and_ident(TRUE),
3080 rc == FAIL ? US"" : US"temporarily ",
3084 if (!drop) return 0;
3086 log_close_event(US"by DROP in ACL");
3088 /* Run the not-quit ACL, but without any custom messages. This should not be a
3089 problem, because we get here only if some other ACL has issued "drop", and
3090 in that case, *its* custom messages will have been used above. */
3092 smtp_notquit_exit(US"acl-drop", NULL, NULL);
3094 /* An overenthusiastic fail2ban/iptables implimentation has been seen to result
3095 in the TCP conn staying open, and retrying, despite this process exiting. A
3096 malicious client could possibly do the same, tying up server netowrking
3097 resources. Close the socket explicitly to try to avoid that (there's a note in
3098 the Linux socket(7) manpage, SO_LINGER para, to the effect that exim() without
3099 close() results in the socket always lingering). */
3101 (void) poll_one_fd(fileno(smtp_in), POLLIN, 200);
3102 DEBUG(D_any) debug_printf_indent("SMTP(close)>>\n");
3103 (void) fclose(smtp_in);
3104 (void) fclose(smtp_out);
3112 /*************************************************
3113 * Handle SMTP exit when QUIT is not given *
3114 *************************************************/
3116 /* This function provides a logging/statistics hook for when an SMTP connection
3117 is dropped on the floor or the other end goes away. It's a global function
3118 because it's called from receive.c as well as this module. As well as running
3119 the NOTQUIT ACL, if there is one, this function also outputs a final SMTP
3120 response, either with a custom message from the ACL, or using a default. There
3121 is one case, however, when no message is output - after "drop". In that case,
3122 the ACL that obeyed "drop" has already supplied the custom message, and NULL is
3123 passed to this function.
3125 In case things go wrong while processing this function, causing an error that
3126 may re-enter this function, there is a recursion check.
3129 reason What $smtp_notquit_reason will be set to in the ACL;
3130 if NULL, the ACL is not run
3131 code The error code to return as part of the response
3132 defaultrespond The default message if there's no user_msg
3138 smtp_notquit_exit(uschar *reason, uschar *code, uschar *defaultrespond, ...)
3141 uschar *user_msg = NULL;
3142 uschar *log_msg = NULL;
3144 /* Check for recursive call */
3146 if (fl.smtp_exit_function_called)
3148 log_write(0, LOG_PANIC, "smtp_notquit_exit() called more than once (%s)",
3152 fl.smtp_exit_function_called = TRUE;
3154 /* Call the not-QUIT ACL, if there is one, unless no reason is given. */
3156 if (acl_smtp_notquit && reason)
3158 smtp_notquit_reason = reason;
3159 if ((rc = acl_check(ACL_WHERE_NOTQUIT, NULL, acl_smtp_notquit, &user_msg,
3160 &log_msg)) == ERROR)
3161 log_write(0, LOG_MAIN|LOG_PANIC, "ACL for not-QUIT returned ERROR: %s",
3165 /* If the connection was dropped, we certainly are no longer talking TLS */
3166 tls_in.active.sock = -1;
3168 /* Write an SMTP response if we are expected to give one. As the default
3169 responses are all internal, they should be reasonable size. */
3171 if (code && defaultrespond)
3174 smtp_respond(code, 3, TRUE, user_msg);
3180 va_start(ap, defaultrespond);
3181 g = string_vformat(NULL, SVFMT_EXTEND|SVFMT_REBUFFER, CS defaultrespond, ap);
3183 smtp_printf("%s %s\r\n", FALSE, code, string_from_gstring(g));
3192 /*************************************************
3193 * Verify HELO argument *
3194 *************************************************/
3196 /* This function is called if helo_verify_hosts or helo_try_verify_hosts is
3197 matched. It is also called from ACL processing if verify = helo is used and
3198 verification was not previously tried (i.e. helo_try_verify_hosts was not
3199 matched). The result of its processing is to set helo_verified and
3200 helo_verify_failed. These variables should both be FALSE for this function to
3203 Note that EHLO/HELO is legitimately allowed to quote an address literal. Allow
3204 for IPv6 ::ffff: literals.
3207 Returns: TRUE if testing was completed;
3208 FALSE on a temporary failure
3212 smtp_verify_helo(void)
3216 HDEBUG(D_receive) debug_printf("verifying EHLO/HELO argument \"%s\"\n",
3219 if (sender_helo_name == NULL)
3221 HDEBUG(D_receive) debug_printf("no EHLO/HELO command was issued\n");
3224 /* Deal with the case of -bs without an IP address */
3226 else if (sender_host_address == NULL)
3228 HDEBUG(D_receive) debug_printf("no client IP address: assume success\n");
3229 f.helo_verified = TRUE;
3232 /* Deal with the more common case when there is a sending IP address */
3234 else if (sender_helo_name[0] == '[')
3236 f.helo_verified = Ustrncmp(sender_helo_name+1, sender_host_address,
3237 Ustrlen(sender_host_address)) == 0;
3240 if (!f.helo_verified)
3242 if (strncmpic(sender_host_address, US"::ffff:", 7) == 0)
3243 f.helo_verified = Ustrncmp(sender_helo_name + 1,
3244 sender_host_address + 7, Ustrlen(sender_host_address) - 7) == 0;
3249 { if (f.helo_verified) debug_printf("matched host address\n"); }
3252 /* Do a reverse lookup if one hasn't already given a positive or negative
3253 response. If that fails, or the name doesn't match, try checking with a forward
3258 if (sender_host_name == NULL && !host_lookup_failed)
3259 yield = host_name_lookup() != DEFER;
3261 /* If a host name is known, check it and all its aliases. */
3263 if (sender_host_name)
3264 if ((f.helo_verified = strcmpic(sender_host_name, sender_helo_name) == 0))
3266 sender_helo_dnssec = sender_host_dnssec;
3267 HDEBUG(D_receive) debug_printf("matched host name\n");
3271 uschar **aliases = sender_host_aliases;
3273 if ((f.helo_verified = strcmpic(*aliases++, sender_helo_name) == 0))
3275 sender_helo_dnssec = sender_host_dnssec;
3279 HDEBUG(D_receive) if (f.helo_verified)
3280 debug_printf("matched alias %s\n", *(--aliases));
3283 /* Final attempt: try a forward lookup of the helo name */
3285 if (!f.helo_verified)
3289 {.name = sender_helo_name, .address = NULL, .mx = MX_NONE, .next = NULL};
3291 {.request = US"*", .require = US""};
3293 HDEBUG(D_receive) debug_printf("getting IP address for %s\n",
3295 rc = host_find_bydns(&h, NULL, HOST_FIND_BY_A | HOST_FIND_BY_AAAA,
3296 NULL, NULL, NULL, &d, NULL, NULL);
3297 if (rc == HOST_FOUND || rc == HOST_FOUND_LOCAL)
3298 for (host_item * hh = &h; hh; hh = hh->next)
3299 if (Ustrcmp(hh->address, sender_host_address) == 0)
3301 f.helo_verified = TRUE;
3302 if (h.dnssec == DS_YES) sender_helo_dnssec = TRUE;
3304 debug_printf("IP address for %s matches calling address\n"
3305 "Forward DNS security status: %sverified\n",
3306 sender_helo_name, sender_helo_dnssec ? "" : "un");
3312 if (!f.helo_verified) f.helo_verify_failed = TRUE; /* We've tried ... */
3319 /*************************************************
3320 * Send user response message *
3321 *************************************************/
3323 /* This function is passed a default response code and a user message. It calls
3324 smtp_message_code() to check and possibly modify the response code, and then
3325 calls smtp_respond() to transmit the response. I put this into a function
3326 just to avoid a lot of repetition.
3329 code the response code
3330 user_msg the user message
3336 smtp_user_msg(uschar *code, uschar *user_msg)
3339 smtp_message_code(&code, &len, &user_msg, NULL, TRUE);
3340 smtp_respond(code, len, TRUE, user_msg);
3346 smtp_in_auth(auth_instance *au, uschar ** smtp_resp, uschar ** errmsg)
3348 const uschar *set_id = NULL;
3351 /* Set up globals for error messages */
3353 authenticator_name = au->name;
3354 driver_srcfile = au->srcfile;
3355 driver_srcline = au->srcline;
3357 /* Run the checking code, passing the remainder of the command line as
3358 data. Initials the $auth<n> variables as empty. Initialize $0 empty and set
3359 it as the only set numerical variable. The authenticator may set $auth<n>
3360 and also set other numeric variables. The $auth<n> variables are preferred
3361 nowadays; the numerical variables remain for backwards compatibility.
3363 Afterwards, have a go at expanding the set_id string, even if
3364 authentication failed - for bad passwords it can be useful to log the
3365 userid. On success, require set_id to expand and exist, and put it in
3366 authenticated_id. Save this in permanent store, as the working store gets
3367 reset at HELO, RSET, etc. */
3369 for (int i = 0; i < AUTH_VARS; i++) auth_vars[i] = NULL;
3371 expand_nlength[0] = 0; /* $0 contains nothing */
3373 rc = (au->info->servercode)(au, smtp_cmd_data);
3374 if (au->set_id) set_id = expand_string(au->set_id);
3375 expand_nmax = -1; /* Reset numeric variables */
3376 for (int i = 0; i < AUTH_VARS; i++) auth_vars[i] = NULL; /* Reset $auth<n> */
3377 driver_srcfile = authenticator_name = NULL; driver_srcline = 0;
3379 /* The value of authenticated_id is stored in the spool file and printed in
3380 log lines. It must not contain binary zeros or newline characters. In
3381 normal use, it never will, but when playing around or testing, this error
3382 can (did) happen. To guard against this, ensure that the id contains only
3383 printing characters. */
3385 if (set_id) set_id = string_printing(set_id);
3387 /* For the non-OK cases, set up additional logging data if set_id
3391 set_id = set_id && *set_id
3392 ? string_sprintf(" (set_id=%s)", set_id) : US"";
3394 /* Switch on the result */
3399 if (!au->set_id || set_id) /* Complete success */
3401 if (set_id) authenticated_id = string_copy_perm(set_id, TRUE);
3402 sender_host_authenticated = au->name;
3403 sender_host_auth_pubname = au->public_name;
3404 authentication_failed = FALSE;
3405 authenticated_fail_id = NULL; /* Impossible to already be set? */
3408 (sender_host_address ? protocols : protocols_local)
3409 [pextend + pauthed + (tls_in.active.sock >= 0 ? pcrpted:0)];
3410 *smtp_resp = *errmsg = US"235 Authentication succeeded";
3411 authenticated_by = au;
3415 /* Authentication succeeded, but we failed to expand the set_id string.
3416 Treat this as a temporary error. */
3418 auth_defer_msg = expand_string_message;
3422 if (set_id) authenticated_fail_id = string_copy_perm(set_id, TRUE);
3423 *smtp_resp = string_sprintf("435 Unable to authenticate at present%s",
3424 auth_defer_user_msg);
3425 *errmsg = string_sprintf("435 Unable to authenticate at present%s: %s",
3426 set_id, auth_defer_msg);
3430 *smtp_resp = *errmsg = US"501 Invalid base64 data";
3434 *smtp_resp = *errmsg = US"501 Authentication cancelled";
3438 *smtp_resp = *errmsg = US"553 Initial data not expected";
3442 if (set_id) authenticated_fail_id = string_copy_perm(set_id, TRUE);
3443 *smtp_resp = US"535 Incorrect authentication data";
3444 *errmsg = string_sprintf("535 Incorrect authentication data%s", set_id);
3448 if (set_id) authenticated_fail_id = string_copy_perm(set_id, TRUE);
3449 *smtp_resp = US"435 Internal error";
3450 *errmsg = string_sprintf("435 Internal error%s: return %d from authentication "
3451 "check", set_id, rc);
3463 qualify_recipient(uschar ** recipient, uschar * smtp_cmd_data, uschar * tag)
3466 if (f.allow_unqualified_recipient || strcmpic(*recipient, US"postmaster") == 0)
3468 DEBUG(D_receive) debug_printf("unqualified address %s accepted\n",
3470 rd = Ustrlen(recipient) + 1;
3471 /* deconst ok as *recipient was not const */
3472 *recipient = US rewrite_address_qualify(*recipient, TRUE);
3475 smtp_printf("501 %s: recipient address must contain a domain\r\n", FALSE,
3477 log_write(L_smtp_syntax_error,
3478 LOG_MAIN|LOG_REJECT, "unqualified %s rejected: <%s> %s%s",
3479 tag, *recipient, host_and_ident(TRUE), host_lookup_msg);
3487 smtp_quit_handler(uschar ** user_msgp, uschar ** log_msgp)
3490 f.smtp_in_quit = TRUE;
3491 incomplete_transaction_log(US"QUIT");
3493 && acl_check(ACL_WHERE_QUIT, NULL, acl_smtp_quit, user_msgp, log_msgp)
3495 log_write(0, LOG_MAIN|LOG_PANIC, "ACL for QUIT returned ERROR: %s",
3498 #ifdef EXIM_TCP_CORK
3499 (void) setsockopt(fileno(smtp_out), IPPROTO_TCP, EXIM_TCP_CORK, US &on, sizeof(on));
3503 smtp_respond(US"221", 3, TRUE, *user_msgp);
3505 smtp_printf("221 %s closing connection\r\n", FALSE, smtp_active_hostname);
3507 #ifdef SERVERSIDE_CLOSE_NOWAIT
3508 # ifndef DISABLE_TLS
3509 tls_close(NULL, TLS_SHUTDOWN_NOWAIT);
3512 log_close_event(US"by QUIT");
3515 # ifndef DISABLE_TLS
3516 tls_close(NULL, TLS_SHUTDOWN_WAIT);
3519 log_close_event(US"by QUIT");
3521 /* Pause, hoping client will FIN first so that they get the TIME_WAIT.
3522 The socket should become readble (though with no data) */
3524 (void) poll_one_fd(fileno(smtp_in), POLLIN, 200);
3525 #endif /*!SERVERSIDE_CLOSE_NOWAIT*/
3530 smtp_rset_handler(void)
3533 incomplete_transaction_log(US"RSET");
3534 smtp_printf("250 Reset OK\r\n", FALSE);
3535 cmd_list[CL_RSET].is_mail_cmd = FALSE;
3536 if (chunking_state > CHUNKING_OFFERED)
3537 chunking_state = CHUNKING_OFFERED;
3542 expand_mailmax(const uschar * s)
3544 if (!(s = expand_cstring(s)))
3545 log_write(0, LOG_MAIN|LOG_PANIC, "failed to expand smtp_accept_max_per_connection");
3546 return *s ? Uatoi(s) : 0;
3549 /*************************************************
3550 * Initialize for SMTP incoming message *
3551 *************************************************/
3553 /* This function conducts the initial dialogue at the start of an incoming SMTP
3554 message, and builds a list of recipients. However, if the incoming message
3555 is part of a batch (-bS option) a separate function is called since it would
3556 be messy having tests splattered about all over this function. This function
3557 therefore handles the case where interaction is occurring. The input and output
3558 files are set up in smtp_in and smtp_out.
3560 The global recipients_list is set to point to a vector of recipient_item
3561 blocks, whose number is given by recipients_count. This is extended by the
3562 receive_add_recipient() function. The global variable sender_address is set to
3563 the sender's address. The yield is +1 if a message has been successfully
3564 started, 0 if a QUIT command was encountered or the connection was refused from
3565 the particular host, or -1 if the connection was lost.
3569 Returns: > 0 message successfully started (reached DATA)
3570 = 0 QUIT read or end of file reached or call refused
3575 smtp_setup_msg(void)
3578 BOOL toomany = FALSE;
3579 BOOL discarded = FALSE;
3580 BOOL last_was_rej_mail = FALSE;
3581 BOOL last_was_rcpt = FALSE;
3582 rmark reset_point = store_mark();
3584 DEBUG(D_receive) debug_printf("smtp_setup_msg entered\n");
3586 /* Reset for start of new message. We allow one RSET not to be counted as a
3587 nonmail command, for those MTAs that insist on sending it between every
3588 message. Ditto for EHLO/HELO and for STARTTLS, to allow for going in and out of
3589 TLS between messages (an Exim client may do this if it has messages queued up
3590 for the host). Note: we do NOT reset AUTH at this point. */
3592 reset_point = smtp_reset(reset_point);
3593 message_ended = END_NOTSTARTED;
3595 chunking_state = f.chunking_offered ? CHUNKING_OFFERED : CHUNKING_NOT_OFFERED;
3597 cmd_list[CL_RSET].is_mail_cmd = TRUE;
3598 cmd_list[CL_HELO].is_mail_cmd = TRUE;
3599 cmd_list[CL_EHLO].is_mail_cmd = TRUE;
3601 cmd_list[CL_STLS].is_mail_cmd = TRUE;
3604 if (lwr_receive_getc != NULL)
3606 /* This should have already happened, but if we've gotten confused,
3607 force a reset here. */
3608 DEBUG(D_receive) debug_printf("WARNING: smtp_setup_msg had to restore receive functions to lowers\n");
3609 bdat_pop_receive_functions();
3612 /* Set the local signal handler for SIGTERM - it tries to end off tidily */
3614 had_command_sigterm = 0;
3615 os_non_restarting_signal(SIGTERM, command_sigterm_handler);
3617 /* Batched SMTP is handled in a different function. */
3619 if (smtp_batched_input) return smtp_setup_batch_msg();
3622 if (smtp_in) /* Avoid pure-ACKs while in cmd pingpong phase */
3623 (void) setsockopt(fileno(smtp_in), IPPROTO_TCP, TCP_QUICKACK,
3624 US &off, sizeof(off));
3627 /* Deal with SMTP commands. This loop is exited by setting done to a POSITIVE
3628 value. The values are 2 larger than the required yield of the function. */
3632 const uschar **argv;
3633 uschar *etrn_command;
3634 uschar *etrn_serialize_key;
3636 uschar *log_msg, *smtp_code;
3637 uschar *user_msg = NULL;
3638 uschar *recipient = NULL;
3639 uschar *hello = NULL;
3641 BOOL was_rej_mail = FALSE;
3642 BOOL was_rcpt = FALSE;
3643 void (*oldsignal)(int);
3645 int start, end, sender_domain, recipient_domain;
3648 uschar *orcpt = NULL;
3653 /* Check once per STARTTLS or SSL-on-connect for a TLS AUTH */
3654 if ( tls_in.active.sock >= 0
3656 && tls_in.certificate_verified
3657 && cmd_list[CL_TLAU].is_mail_cmd
3660 cmd_list[CL_TLAU].is_mail_cmd = FALSE;
3662 for (auth_instance * au = auths; au; au = au->next)
3663 if (strcmpic(US"tls", au->driver_name) == 0)
3666 && (rc = acl_check(ACL_WHERE_AUTH, NULL, acl_smtp_auth,
3667 &user_msg, &log_msg)) != OK
3669 done = smtp_handle_acl_fail(ACL_WHERE_AUTH, rc, user_msg, log_msg);
3672 smtp_cmd_data = NULL;
3674 if (smtp_in_auth(au, &s, &ss) == OK)
3675 { DEBUG(D_auth) debug_printf("tls auth succeeded\n"); }
3678 DEBUG(D_auth) debug_printf("tls auth not succeeded\n");
3679 #ifndef DISABLE_EVENT
3681 uschar * save_name = sender_host_authenticated, * logmsg;
3682 sender_host_authenticated = au->name;
3683 if ((logmsg = event_raise(event_action, US"auth:fail", s, NULL)))
3684 log_write(0, LOG_MAIN, "%s", logmsg);
3685 sender_host_authenticated = save_name;
3695 switch(smtp_read_command(
3696 #ifndef DISABLE_PIPE_CONNECT
3697 !fl.pipe_connect_acceptable,
3701 GETC_BUFFER_UNLIMITED))
3703 /* The AUTH command is not permitted to occur inside a transaction, and may
3704 occur successfully only once per connection. Actually, that isn't quite
3705 true. When TLS is started, all previous information about a connection must
3706 be discarded, so a new AUTH is permitted at that time.
3708 AUTH may only be used when it has been advertised. However, it seems that
3709 there are clients that send AUTH when it hasn't been advertised, some of
3710 them even doing this after HELO. And there are MTAs that accept this. Sigh.
3711 So there's a get-out that allows this to happen.
3713 AUTH is initially labelled as a "nonmail command" so that one occurrence
3714 doesn't get counted. We change the label here so that multiple failing
3715 AUTHS will eventually hit the nonmail threshold. */
3719 authentication_failed = TRUE;
3720 cmd_list[CL_AUTH].is_mail_cmd = FALSE;
3722 if (!fl.auth_advertised && !f.allow_auth_unadvertised)
3724 done = synprot_error(L_smtp_protocol_error, 503, NULL,
3725 US"AUTH command used when not advertised");
3728 if (sender_host_authenticated)
3730 done = synprot_error(L_smtp_protocol_error, 503, NULL,
3731 US"already authenticated");
3736 done = synprot_error(L_smtp_protocol_error, 503, NULL,
3737 US"not permitted in mail transaction");
3744 && (rc = acl_check(ACL_WHERE_AUTH, NULL, acl_smtp_auth,
3745 &user_msg, &log_msg)) != OK
3748 done = smtp_handle_acl_fail(ACL_WHERE_AUTH, rc, user_msg, log_msg);
3752 /* Find the name of the requested authentication mechanism. */
3755 for (; (c = *smtp_cmd_data) && !isspace(c); smtp_cmd_data++)
3756 if (!isalnum(c) && c != '-' && c != '_')
3758 done = synprot_error(L_smtp_syntax_error, 501, NULL,
3759 US"invalid character in authentication mechanism name");
3763 /* If not at the end of the line, we must be at white space. Terminate the
3764 name and move the pointer on to any data that may be present. */
3768 *smtp_cmd_data++ = 0;
3769 while (isspace(*smtp_cmd_data)) smtp_cmd_data++;
3772 /* Search for an authentication mechanism which is configured for use
3773 as a server and which has been advertised (unless, sigh, allow_auth_
3774 unadvertised is set). */
3778 uschar * smtp_resp, * errmsg;
3780 for (au = auths; au; au = au->next)
3781 if (strcmpic(s, au->public_name) == 0 && au->server &&
3782 (au->advertised || f.allow_auth_unadvertised))
3787 int rc = smtp_in_auth(au, &smtp_resp, &errmsg);
3789 smtp_printf("%s\r\n", FALSE, smtp_resp);
3792 uschar * logmsg = NULL;
3793 #ifndef DISABLE_EVENT
3794 {uschar * save_name = sender_host_authenticated;
3795 sender_host_authenticated = au->name;
3796 logmsg = event_raise(event_action, US"auth:fail", smtp_resp, NULL);
3797 sender_host_authenticated = save_name;
3801 log_write(0, LOG_MAIN|LOG_REJECT, "%s", logmsg);
3803 log_write(0, LOG_MAIN|LOG_REJECT, "%s authenticator failed for %s: %s",
3804 au->name, host_and_ident(FALSE), errmsg);
3808 done = synprot_error(L_smtp_protocol_error, 504, NULL,
3809 string_sprintf("%s authentication mechanism not supported", s));
3812 break; /* AUTH_CMD */
3814 /* The HELO/EHLO commands are permitted to appear in the middle of a
3815 session as well as at the beginning. They have the effect of a reset in
3816 addition to their other functions. Their absence at the start cannot be
3817 taken to be an error.
3821 If the EHLO command is not acceptable to the SMTP server, 501, 500,
3822 or 502 failure replies MUST be returned as appropriate. The SMTP
3823 server MUST stay in the same state after transmitting these replies
3824 that it was in before the EHLO was received.
3826 Therefore, we do not do the reset until after checking the command for
3827 acceptability. This change was made for Exim release 4.11. Previously
3828 it did the reset first. */
3841 HELO_EHLO: /* Common code for HELO and EHLO */
3842 cmd_list[CL_HELO].is_mail_cmd = FALSE;
3843 cmd_list[CL_EHLO].is_mail_cmd = FALSE;
3845 /* Reject the HELO if its argument was invalid or non-existent. A
3846 successful check causes the argument to be saved in malloc store. */
3848 if (!check_helo(smtp_cmd_data))
3850 smtp_printf("501 Syntactically invalid %s argument(s)\r\n", FALSE, hello);
3852 log_write(0, LOG_MAIN|LOG_REJECT, "rejected %s from %s: syntactically "
3853 "invalid argument(s): %s", hello, host_and_ident(FALSE),
3854 *smtp_cmd_argument == 0 ? US"(no argument given)" :
3855 string_printing(smtp_cmd_argument));
3857 if (++synprot_error_count > smtp_max_synprot_errors)
3859 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
3860 "syntax or protocol errors (last command was \"%s\", %s)",
3861 host_and_ident(FALSE), string_printing(smtp_cmd_buffer),
3862 string_from_gstring(s_connhad_log(NULL))
3870 /* If sender_host_unknown is true, we have got here via the -bs interface,
3871 not called from inetd. Otherwise, we are running an IP connection and the
3872 host address will be set. If the helo name is the primary name of this
3873 host and we haven't done a reverse lookup, force one now. If helo_verify_required
3874 is set, ensure that the HELO name matches the actual host. If helo_verify
3875 is set, do the same check, but softly. */
3877 if (!f.sender_host_unknown)
3879 BOOL old_helo_verified = f.helo_verified;
3880 uschar *p = smtp_cmd_data;
3882 while (*p != 0 && !isspace(*p)) { *p = tolower(*p); p++; }
3885 /* Force a reverse lookup if HELO quoted something in helo_lookup_domains
3886 because otherwise the log can be confusing. */
3888 if ( !sender_host_name
3889 && match_isinlist(sender_helo_name, CUSS &helo_lookup_domains, 0,
3890 &domainlist_anchor, NULL, MCL_DOMAIN, TRUE, NULL) == OK)
3891 (void)host_name_lookup();
3893 /* Rebuild the fullhost info to include the HELO name (and the real name
3894 if it was looked up.) */
3896 host_build_sender_fullhost(); /* Rebuild */
3897 set_process_info("handling%s incoming connection from %s",
3898 tls_in.active.sock >= 0 ? " TLS" : "", host_and_ident(FALSE));
3900 /* Verify if configured. This doesn't give much security, but it does
3901 make some people happy to be able to do it. If helo_verify_required is set,
3902 (host matches helo_verify_hosts) failure forces rejection. If helo_verify
3903 is set (host matches helo_try_verify_hosts), it does not. This is perhaps
3904 now obsolescent, since the verification can now be requested selectively
3907 f.helo_verified = f.helo_verify_failed = sender_helo_dnssec = FALSE;
3908 if (fl.helo_verify_required || fl.helo_verify)
3910 BOOL tempfail = !smtp_verify_helo();
3911 if (!f.helo_verified)
3913 if (fl.helo_verify_required)
3915 smtp_printf("%d %s argument does not match calling host\r\n", FALSE,
3916 tempfail? 451 : 550, hello);
3917 log_write(0, LOG_MAIN|LOG_REJECT, "%srejected \"%s %s\" from %s",
3918 tempfail? "temporarily " : "",
3919 hello, sender_helo_name, host_and_ident(FALSE));
3920 f.helo_verified = old_helo_verified;
3921 break; /* End of HELO/EHLO processing */
3923 HDEBUG(D_all) debug_printf("%s verification failed but host is in "
3924 "helo_try_verify_hosts\n", hello);
3930 /* set up SPF context */
3931 spf_conn_init(sender_helo_name, sender_host_address);
3934 /* Apply an ACL check if one is defined; afterwards, recheck
3935 synchronization in case the client started sending in a delay. */
3938 if ((rc = acl_check(ACL_WHERE_HELO, NULL, acl_smtp_helo,
3939 &user_msg, &log_msg)) != OK)
3941 done = smtp_handle_acl_fail(ACL_WHERE_HELO, rc, user_msg, log_msg);
3942 sender_helo_name = NULL;
3943 host_build_sender_fullhost(); /* Rebuild */
3946 #ifndef DISABLE_PIPE_CONNECT
3947 else if (!fl.pipe_connect_acceptable && !check_sync())
3949 else if (!check_sync())
3953 /* Generate an OK reply. The default string includes the ident if present,
3954 and also the IP address if present. Reflecting back the ident is intended
3955 as a deterrent to mail forgers. For maximum efficiency, and also because
3956 some broken systems expect each response to be in a single packet, arrange
3957 that the entire reply is sent in one write(). */
3959 fl.auth_advertised = FALSE;
3960 f.smtp_in_pipelining_advertised = FALSE;
3962 fl.tls_advertised = FALSE;
3964 fl.dsn_advertised = FALSE;
3966 fl.smtputf8_advertised = FALSE;
3969 /* Expand the per-connection message count limit option */
3970 smtp_mailcmd_max = expand_mailmax(smtp_accept_max_per_connection);
3972 smtp_code = US"250 "; /* Default response code plus space*/
3975 /* sender_host_name below will be tainted, so save on copy when we hit it */
3976 g = string_get_tainted(24, GET_TAINTED);
3977 g = string_fmt_append(g, "%.3s %s Hello %s%s%s",
3979 smtp_active_hostname,
3980 sender_ident ? sender_ident : US"",
3981 sender_ident ? US" at " : US"",
3982 sender_host_name ? sender_host_name : sender_helo_name);
3984 if (sender_host_address)
3985 g = string_fmt_append(g, " [%s]", sender_host_address);
3988 /* A user-supplied EHLO greeting may not contain more than one line. Note
3989 that the code returned by smtp_message_code() includes the terminating
3990 whitespace character. */
3996 smtp_message_code(&smtp_code, &codelen, &user_msg, NULL, TRUE);
3997 s = string_sprintf("%.*s%s", codelen, smtp_code, user_msg);
3998 if ((ss = strpbrk(CS s, "\r\n")) != NULL)
4000 log_write(0, LOG_MAIN|LOG_PANIC, "EHLO/HELO response must not contain "
4001 "newlines: message truncated: %s", string_printing(s));
4004 g = string_cat(NULL, s);
4007 g = string_catn(g, US"\r\n", 2);
4009 /* If we received EHLO, we must create a multiline response which includes
4010 the functions supported. */
4014 g->s[3] = '-'; /* overwrite the space after the SMTP response code */
4016 /* I'm not entirely happy with this, as an MTA is supposed to check
4017 that it has enough room to accept a message of maximum size before
4018 it sends this. However, there seems little point in not sending it.
4019 The actual size check happens later at MAIL FROM time. By postponing it
4020 till then, VRFY and EXPN can be used after EHLO when space is short. */
4022 if (thismessage_size_limit > 0)
4023 g = string_fmt_append(g, "%.3s-SIZE %d\r\n", smtp_code,
4024 thismessage_size_limit);
4027 g = string_catn(g, smtp_code, 3);
4028 g = string_catn(g, US"-SIZE\r\n", 7);
4031 #ifdef EXPERIMENTAL_ESMTP_LIMITS
4032 if ( (smtp_mailcmd_max > 0 || recipients_max)
4033 && verify_check_host(&limits_advertise_hosts) == OK)
4035 g = string_fmt_append(g, "%.3s-LIMITS", smtp_code);
4036 if (smtp_mailcmd_max > 0)
4037 g = string_fmt_append(g, " MAILMAX=%d", smtp_mailcmd_max);
4039 g = string_fmt_append(g, " RCPTMAX=%d", recipients_max);
4040 g = string_catn(g, US"\r\n", 2);
4044 /* Exim does not do protocol conversion or data conversion. It is 8-bit
4045 clean; if it has an 8-bit character in its hand, it just sends it. It
4046 cannot therefore specify 8BITMIME and remain consistent with the RFCs.
4047 However, some users want this option simply in order to stop MUAs
4048 mangling messages that contain top-bit-set characters. It is therefore
4049 provided as an option. */
4051 if (accept_8bitmime)
4053 g = string_catn(g, smtp_code, 3);
4054 g = string_catn(g, US"-8BITMIME\r\n", 11);
4057 /* Advertise DSN support if configured to do so. */
4058 if (verify_check_host(&dsn_advertise_hosts) != FAIL)
4060 g = string_catn(g, smtp_code, 3);
4061 g = string_catn(g, US"-DSN\r\n", 6);
4062 fl.dsn_advertised = TRUE;
4065 /* Advertise ETRN/VRFY/EXPN if there's are ACL checking whether a host is
4066 permitted to issue them; a check is made when any host actually tries. */
4070 g = string_catn(g, smtp_code, 3);
4071 g = string_catn(g, US"-ETRN\r\n", 7);
4075 g = string_catn(g, smtp_code, 3);
4076 g = string_catn(g, US"-VRFY\r\n", 7);
4080 g = string_catn(g, smtp_code, 3);
4081 g = string_catn(g, US"-EXPN\r\n", 7);
4084 /* Exim is quite happy with pipelining, so let the other end know that
4085 it is safe to use it, unless advertising is disabled. */
4087 if ( f.pipelining_enable
4088 && verify_check_host(&pipelining_advertise_hosts) == OK)
4090 g = string_catn(g, smtp_code, 3);
4091 g = string_catn(g, US"-PIPELINING\r\n", 13);
4092 sync_cmd_limit = NON_SYNC_CMD_PIPELINING;
4093 f.smtp_in_pipelining_advertised = TRUE;
4095 #ifndef DISABLE_PIPE_CONNECT
4096 if (fl.pipe_connect_acceptable)
4098 f.smtp_in_early_pipe_advertised = TRUE;
4099 g = string_catn(g, smtp_code, 3);
4100 g = string_catn(g, US"-" EARLY_PIPE_FEATURE_NAME "\r\n", EARLY_PIPE_FEATURE_LEN+3);
4106 /* If any server authentication mechanisms are configured, advertise
4107 them if the current host is in auth_advertise_hosts. The problem with
4108 advertising always is that some clients then require users to
4109 authenticate (and aren't configurable otherwise) even though it may not
4110 be necessary (e.g. if the host is in host_accept_relay).
4112 RFC 2222 states that SASL mechanism names contain only upper case
4113 letters, so output the names in upper case, though we actually recognize
4114 them in either case in the AUTH command. */
4118 && !sender_host_authenticated
4120 && verify_check_host(&auth_advertise_hosts) == OK
4124 for (auth_instance * au = auths; au; au = au->next)
4126 au->advertised = FALSE;
4129 DEBUG(D_auth+D_expand) debug_printf_indent(
4130 "Evaluating advertise_condition for %s %s athenticator\n",
4131 au->name, au->public_name);
4132 if ( !au->advertise_condition
4133 || expand_check_condition(au->advertise_condition, au->name,
4140 g = string_catn(g, smtp_code, 3);
4141 g = string_catn(g, US"-AUTH", 5);
4143 fl.auth_advertised = TRUE;
4145 saveptr = gstring_length(g);
4146 g = string_catn(g, US" ", 1);
4147 g = string_cat(g, au->public_name);
4148 while (++saveptr < g->ptr) g->s[saveptr] = toupper(g->s[saveptr]);
4149 au->advertised = TRUE;
4154 if (!first) g = string_catn(g, US"\r\n", 2);
4157 /* RFC 3030 CHUNKING */
4159 if (verify_check_host(&chunking_advertise_hosts) != FAIL)
4161 g = string_catn(g, smtp_code, 3);
4162 g = string_catn(g, US"-CHUNKING\r\n", 11);
4163 f.chunking_offered = TRUE;
4164 chunking_state = CHUNKING_OFFERED;
4167 /* Advertise TLS (Transport Level Security) aka SSL (Secure Socket Layer)
4168 if it has been included in the binary, and the host matches
4169 tls_advertise_hosts. We must *not* advertise if we are already in a
4170 secure connection. */
4173 if (tls_in.active.sock < 0 &&
4174 verify_check_host(&tls_advertise_hosts) != FAIL)
4176 g = string_catn(g, smtp_code, 3);
4177 g = string_catn(g, US"-STARTTLS\r\n", 11);
4178 fl.tls_advertised = TRUE;
4182 #ifndef DISABLE_PRDR
4183 /* Per Recipient Data Response, draft by Eric A. Hall extending RFC */
4186 g = string_catn(g, smtp_code, 3);
4187 g = string_catn(g, US"-PRDR\r\n", 7);
4192 if ( accept_8bitmime
4193 && verify_check_host(&smtputf8_advertise_hosts) != FAIL)
4195 g = string_catn(g, smtp_code, 3);
4196 g = string_catn(g, US"-SMTPUTF8\r\n", 11);
4197 fl.smtputf8_advertised = TRUE;
4201 /* Finish off the multiline reply with one that is always available. */
4203 g = string_catn(g, smtp_code, 3);
4204 g = string_catn(g, US" HELP\r\n", 7);
4207 /* Terminate the string (for debug), write it, and note that HELO/EHLO
4212 int len = len_string_from_gstring(g, &ehlo_resp);
4214 if (tls_in.active.sock >= 0)
4215 (void) tls_write(NULL, ehlo_resp, len,
4216 # ifndef DISABLE_PIPE_CONNECT
4217 fl.pipe_connect_acceptable && pipeline_connect_sends());
4223 (void) fwrite(ehlo_resp, 1, len, smtp_out);
4225 DEBUG(D_receive) for (const uschar * t, * s = ehlo_resp;
4226 s && (t = Ustrchr(s, '\r'));
4227 s = t + 2) /* \r\n */
4228 debug_printf("%s %.*s\n",
4229 s == g->s ? "SMTP>>" : " ",
4231 fl.helo_seen = TRUE;
4234 /* Reset the protocol and the state, abandoning any previous message. */
4236 (sender_host_address ? protocols : protocols_local)
4238 ? pextend + (sender_host_authenticated ? pauthed : 0)
4240 + (tls_in.active.sock >= 0 ? pcrpted : 0)
4242 cancel_cutthrough_connection(TRUE, US"sent EHLO response");
4243 reset_point = smtp_reset(reset_point);
4245 break; /* HELO/EHLO */
4248 /* The MAIL command requires an address as an operand. All we do
4249 here is to parse it for syntactic correctness. The form "<>" is
4250 a special case which converts into an empty string. The start/end
4251 pointers in the original are not used further for this address, as
4252 it is the canonical extracted address which is all that is kept. */
4256 smtp_mailcmd_count++; /* Count for limit and ratelimit */
4258 was_rej_mail = TRUE; /* Reset if accepted */
4259 env_mail_type_t * mail_args; /* Sanity check & validate args */
4262 if ( fl.helo_verify_required
4263 || verify_check_host(&hosts_require_helo) == OK)
4265 smtp_printf("503 HELO or EHLO required\r\n", FALSE);
4266 log_write(0, LOG_MAIN|LOG_REJECT, "rejected MAIL from %s: no "
4267 "HELO/EHLO given", host_and_ident(FALSE));
4270 else if (smtp_mailcmd_max < 0)
4271 smtp_mailcmd_max = expand_mailmax(smtp_accept_max_per_connection);
4275 done = synprot_error(L_smtp_protocol_error, 503, NULL,
4276 US"sender already given");
4280 if (!*smtp_cmd_data)
4282 done = synprot_error(L_smtp_protocol_error, 501, NULL,
4283 US"MAIL must have an address operand");
4287 /* Check to see if the limit for messages per connection would be
4288 exceeded by accepting further messages. */
4290 if (smtp_mailcmd_max > 0 && smtp_mailcmd_count > smtp_mailcmd_max)
4292 smtp_printf("421 too many messages in this connection\r\n", FALSE);
4293 log_write(0, LOG_MAIN|LOG_REJECT, "rejected MAIL command %s: too many "
4294 "messages in one connection", host_and_ident(TRUE));
4298 /* Reset for start of message - even if this is going to fail, we
4299 obviously need to throw away any previous data. */
4301 cancel_cutthrough_connection(TRUE, US"MAIL received");
4302 reset_point = smtp_reset(reset_point);
4304 sender_data = recipient_data = NULL;
4306 /* Loop, checking for ESMTP additions to the MAIL FROM command. */
4308 if (fl.esmtp) for(;;)
4310 uschar *name, *value, *end;
4311 unsigned long int size;
4312 BOOL arg_error = FALSE;
4314 if (!extract_option(&name, &value)) break;
4316 for (mail_args = env_mail_type_list;
4317 mail_args->value != ENV_MAIL_OPT_NULL;
4320 if (strcmpic(name, mail_args->name) == 0)
4322 if (mail_args->need_value && strcmpic(value, US"") == 0)
4325 switch(mail_args->value)
4327 /* Handle SIZE= by reading the value. We don't do the check till later,
4328 in order to be able to log the sender address on failure. */
4329 case ENV_MAIL_OPT_SIZE:
4330 if (((size = Ustrtoul(value, &end, 10)), *end == 0))
4332 if ((size == ULONG_MAX && errno == ERANGE) || size > INT_MAX)
4334 message_size = (int)size;
4340 /* If this session was initiated with EHLO and accept_8bitmime is set,
4341 Exim will have indicated that it supports the BODY=8BITMIME option. In
4342 fact, it does not support this according to the RFCs, in that it does not
4343 take any special action for forwarding messages containing 8-bit
4344 characters. That is why accept_8bitmime is not the default setting, but
4345 some sites want the action that is provided. We recognize both "8BITMIME"
4346 and "7BIT" as body types, but take no action. */
4347 case ENV_MAIL_OPT_BODY:
4348 if (accept_8bitmime) {
4349 if (strcmpic(value, US"8BITMIME") == 0)
4351 else if (strcmpic(value, US"7BIT") == 0)
4356 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4357 US"invalid data for BODY");
4360 DEBUG(D_receive) debug_printf("8BITMIME: %d\n", body_8bitmime);
4366 /* Handle the two DSN options, but only if configured to do so (which
4367 will have caused "DSN" to be given in the EHLO response). The code itself
4368 is included only if configured in at build time. */
4370 case ENV_MAIL_OPT_RET:
4371 if (fl.dsn_advertised)
4373 /* Check if RET has already been set */
4376 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4377 US"RET can be specified once only");
4380 dsn_ret = strcmpic(value, US"HDRS") == 0
4382 : strcmpic(value, US"FULL") == 0
4385 DEBUG(D_receive) debug_printf("DSN_RET: %d\n", dsn_ret);
4386 /* Check for invalid invalid value, and exit with error */
4389 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4390 US"Value for RET is invalid");
4395 case ENV_MAIL_OPT_ENVID:
4396 if (fl.dsn_advertised)
4398 /* Check if the dsn envid has been already set */
4401 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4402 US"ENVID can be specified once only");
4405 dsn_envid = string_copy(value);
4406 DEBUG(D_receive) debug_printf("DSN_ENVID: %s\n", dsn_envid);
4410 /* Handle the AUTH extension. If the value given is not "<>" and either
4411 the ACL says "yes" or there is no ACL but the sending host is
4412 authenticated, we set it up as the authenticated sender. However, if the
4413 authenticator set a condition to be tested, we ignore AUTH on MAIL unless
4414 the condition is met. The value of AUTH is an xtext, which means that +,
4415 = and cntrl chars are coded in hex; however "<>" is unaffected by this
4417 case ENV_MAIL_OPT_AUTH:
4418 if (Ustrcmp(value, "<>") != 0)
4423 if (auth_xtextdecode(value, &authenticated_sender) < 0)
4425 /* Put back terminator overrides for error message */
4428 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4429 US"invalid data for AUTH");
4432 if (!acl_smtp_mailauth)
4434 ignore_msg = US"client not authenticated";
4435 rc = sender_host_authenticated ? OK : FAIL;
4439 ignore_msg = US"rejected by ACL";
4440 rc = acl_check(ACL_WHERE_MAILAUTH, NULL, acl_smtp_mailauth,
4441 &user_msg, &log_msg);
4447 if (authenticated_by == NULL ||
4448 authenticated_by->mail_auth_condition == NULL ||
4449 expand_check_condition(authenticated_by->mail_auth_condition,
4450 authenticated_by->name, US"authenticator"))
4451 break; /* Accept the AUTH */
4453 ignore_msg = US"server_mail_auth_condition failed";
4454 if (authenticated_id != NULL)
4455 ignore_msg = string_sprintf("%s: authenticated ID=\"%s\"",
4456 ignore_msg, authenticated_id);
4461 authenticated_sender = NULL;
4462 log_write(0, LOG_MAIN, "ignoring AUTH=%s from %s (%s)",
4463 value, host_and_ident(TRUE), ignore_msg);
4466 /* Should only get DEFER or ERROR here. Put back terminator
4467 overrides for error message */
4472 (void)smtp_handle_acl_fail(ACL_WHERE_MAILAUTH, rc, user_msg,
4479 #ifndef DISABLE_PRDR
4480 case ENV_MAIL_OPT_PRDR:
4482 prdr_requested = TRUE;
4487 case ENV_MAIL_OPT_UTF8:
4488 if (!fl.smtputf8_advertised)
4490 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4491 US"SMTPUTF8 used when not advertised");
4495 DEBUG(D_receive) debug_printf("smtputf8 requested\n");
4496 message_smtputf8 = allow_utf8_domains = TRUE;
4497 if (Ustrncmp(received_protocol, US"utf8", 4) != 0)
4499 int old_pool = store_pool;
4500 store_pool = POOL_PERM;
4501 received_protocol = string_sprintf("utf8%s", received_protocol);
4502 store_pool = old_pool;
4507 /* No valid option. Stick back the terminator characters and break
4508 the loop. Do the name-terminator second as extract_option sets
4509 value==name when it found no equal-sign.
4510 An error for a malformed address will occur. */
4511 case ENV_MAIL_OPT_NULL:
4519 /* Break out of for loop if switch() had bad argument or
4520 when start of the email address is reached */
4521 if (arg_error) break;
4524 /* If we have passed the threshold for rate limiting, apply the current
4525 delay, and update it for next time, provided this is a limited host. */
4527 if (smtp_mailcmd_count > smtp_rlm_threshold &&
4528 verify_check_host(&smtp_ratelimit_hosts) == OK)
4530 DEBUG(D_receive) debug_printf("rate limit MAIL: delay %.3g sec\n",
4531 smtp_delay_mail/1000.0);
4532 millisleep((int)smtp_delay_mail);
4533 smtp_delay_mail *= smtp_rlm_factor;
4534 if (smtp_delay_mail > (double)smtp_rlm_limit)
4535 smtp_delay_mail = (double)smtp_rlm_limit;
4538 /* Now extract the address, first applying any SMTP-time rewriting. The
4539 TRUE flag allows "<>" as a sender address. */
4541 raw_sender = rewrite_existflags & rewrite_smtp
4542 /* deconst ok as smtp_cmd_data was not const */
4543 ? US rewrite_one(smtp_cmd_data, rewrite_smtp, NULL, FALSE, US"",
4544 global_rewrite_rules)
4548 parse_extract_address(raw_sender, &errmess, &start, &end, &sender_domain,
4553 done = synprot_error(L_smtp_syntax_error, 501, smtp_cmd_data, errmess);
4557 sender_address = raw_sender;
4559 /* If there is a configured size limit for mail, check that this message
4560 doesn't exceed it. The check is postponed to this point so that the sender
4563 if (thismessage_size_limit > 0 && message_size > thismessage_size_limit)
4565 smtp_printf("552 Message size exceeds maximum permitted\r\n", FALSE);
4566 log_write(L_size_reject,
4567 LOG_MAIN|LOG_REJECT, "rejected MAIL FROM:<%s> %s: "
4568 "message too big: size%s=%d max=%d",
4570 host_and_ident(TRUE),
4571 (message_size == INT_MAX)? ">" : "",
4573 thismessage_size_limit);
4574 sender_address = NULL;
4578 /* Check there is enough space on the disk unless configured not to.
4579 When smtp_check_spool_space is set, the check is for thismessage_size_limit
4580 plus the current message - i.e. we accept the message only if it won't
4581 reduce the space below the threshold. Add 5000 to the size to allow for
4582 overheads such as the Received: line and storing of recipients, etc.
4583 By putting the check here, even when SIZE is not given, it allow VRFY
4584 and EXPN etc. to be used when space is short. */
4586 if (!receive_check_fs(
4587 smtp_check_spool_space && message_size >= 0
4588 ? message_size + 5000 : 0))
4590 smtp_printf("452 Space shortage, please try later\r\n", FALSE);
4591 sender_address = NULL;
4595 /* If sender_address is unqualified, reject it, unless this is a locally
4596 generated message, or the sending host or net is permitted to send
4597 unqualified addresses - typically local machines behaving as MUAs -
4598 in which case just qualify the address. The flag is set above at the start
4599 of the SMTP connection. */
4601 if (!sender_domain && *sender_address)
4602 if (f.allow_unqualified_sender)
4604 sender_domain = Ustrlen(sender_address) + 1;
4605 /* deconst ok as sender_address was not const */
4606 sender_address = US rewrite_address_qualify(sender_address, FALSE);
4607 DEBUG(D_receive) debug_printf("unqualified address %s accepted\n",
4612 smtp_printf("501 %s: sender address must contain a domain\r\n", FALSE,
4614 log_write(L_smtp_syntax_error,
4615 LOG_MAIN|LOG_REJECT,
4616 "unqualified sender rejected: <%s> %s%s",
4618 host_and_ident(TRUE),
4620 sender_address = NULL;
4624 /* Apply an ACL check if one is defined, before responding. Afterwards,
4625 when pipelining is not advertised, do another sync check in case the ACL
4626 delayed and the client started sending in the meantime. */
4630 rc = acl_check(ACL_WHERE_MAIL, NULL, acl_smtp_mail, &user_msg, &log_msg);
4631 if (rc == OK && !f.smtp_in_pipelining_advertised && !check_sync())
4637 if (rc == OK || rc == DISCARD)
4639 BOOL more = pipeline_response();
4642 smtp_printf("%s%s%s", more, US"250 OK",
4643 #ifndef DISABLE_PRDR
4644 prdr_requested ? US", PRDR Requested" : US"",
4651 #ifndef DISABLE_PRDR
4653 user_msg = string_sprintf("%s%s", user_msg, US", PRDR Requested");
4655 smtp_user_msg(US"250", user_msg);
4657 smtp_delay_rcpt = smtp_rlr_base;
4658 f.recipients_discarded = (rc == DISCARD);
4659 was_rej_mail = FALSE;
4663 done = smtp_handle_acl_fail(ACL_WHERE_MAIL, rc, user_msg, log_msg);
4664 sender_address = NULL;
4669 /* The RCPT command requires an address as an operand. There may be any
4670 number of RCPT commands, specifying multiple recipients. We build them all
4671 into a data structure. The start/end values given by parse_extract_address
4672 are not used, as we keep only the extracted address. */
4676 /* We got really to many recipients. A check against configured
4677 limits is done later */
4678 if (rcpt_count < 0 || rcpt_count >= INT_MAX/2)
4679 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "Too many recipients: %d", rcpt_count);
4681 was_rcpt = fl.rcpt_in_progress = TRUE;
4683 /* There must be a sender address; if the sender was rejected and
4684 pipelining was advertised, we assume the client was pipelining, and do not
4685 count this as a protocol error. Reset was_rej_mail so that further RCPTs
4686 get the same treatment. */
4688 if (!sender_address)
4690 if (f.smtp_in_pipelining_advertised && last_was_rej_mail)
4692 smtp_printf("503 sender not yet given\r\n", FALSE);
4693 was_rej_mail = TRUE;
4697 done = synprot_error(L_smtp_protocol_error, 503, NULL,
4698 US"sender not yet given");
4699 was_rcpt = FALSE; /* Not a valid RCPT */
4705 /* Check for an operand */
4707 if (!smtp_cmd_data[0])
4709 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4710 US"RCPT must have an address operand");
4715 /* Set the DSN flags orcpt and dsn_flags from the session*/
4719 if (fl.esmtp) for(;;)
4721 uschar *name, *value;
4723 if (!extract_option(&name, &value))
4726 if (fl.dsn_advertised && strcmpic(name, US"ORCPT") == 0)
4728 /* Check whether orcpt has been already set */
4731 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4732 US"ORCPT can be specified once only");
4735 orcpt = string_copy(value);
4736 DEBUG(D_receive) debug_printf("DSN orcpt: %s\n", orcpt);
4739 else if (fl.dsn_advertised && strcmpic(name, US"NOTIFY") == 0)
4741 /* Check if the notify flags have been already set */
4744 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4745 US"NOTIFY can be specified once only");
4748 if (strcmpic(value, US"NEVER") == 0)
4749 dsn_flags |= rf_notify_never;
4756 while (*pp != 0 && *pp != ',') pp++;
4757 if (*pp == ',') *pp++ = 0;
4758 if (strcmpic(p, US"SUCCESS") == 0)
4760 DEBUG(D_receive) debug_printf("DSN: Setting notify success\n");
4761 dsn_flags |= rf_notify_success;
4763 else if (strcmpic(p, US"FAILURE") == 0)
4765 DEBUG(D_receive) debug_printf("DSN: Setting notify failure\n");
4766 dsn_flags |= rf_notify_failure;
4768 else if (strcmpic(p, US"DELAY") == 0)
4770 DEBUG(D_receive) debug_printf("DSN: Setting notify delay\n");
4771 dsn_flags |= rf_notify_delay;
4775 /* Catch any strange values */
4776 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4777 US"Invalid value for NOTIFY parameter");
4782 DEBUG(D_receive) debug_printf("DSN Flags: %x\n", dsn_flags);
4786 /* Unknown option. Stick back the terminator characters and break
4787 the loop. An error for a malformed address will occur. */
4791 DEBUG(D_receive) debug_printf("Invalid RCPT option: %s : %s\n", name, value);
4798 /* Apply SMTP rewriting then extract the working address. Don't allow "<>"
4799 as a recipient address */
4801 recipient = rewrite_existflags & rewrite_smtp
4802 /* deconst ok as smtp_cmd_data was not const */
4803 ? US rewrite_one(smtp_cmd_data, rewrite_smtp, NULL, FALSE, US"",
4804 global_rewrite_rules)
4807 if (!(recipient = parse_extract_address(recipient, &errmess, &start, &end,
4808 &recipient_domain, FALSE)))
4810 done = synprot_error(L_smtp_syntax_error, 501, smtp_cmd_data, errmess);
4815 /* If the recipient address is unqualified, reject it, unless this is a
4816 locally generated message. However, unqualified addresses are permitted
4817 from a configured list of hosts and nets - typically when behaving as
4818 MUAs rather than MTAs. Sad that SMTP is used for both types of traffic,
4819 really. The flag is set at the start of the SMTP connection.
4821 RFC 1123 talks about supporting "the reserved mailbox postmaster"; I always
4822 assumed this meant "reserved local part", but the revision of RFC 821 and
4823 friends now makes it absolutely clear that it means *mailbox*. Consequently
4824 we must always qualify this address, regardless. */
4826 if (!recipient_domain)
4827 if (!(recipient_domain = qualify_recipient(&recipient, smtp_cmd_data,
4834 /* Check maximum allowed */
4836 if (rcpt_count+1 < 0 || rcpt_count > recipients_max && recipients_max > 0)
4838 if (recipients_max_reject)
4841 smtp_printf("552 too many recipients\r\n", FALSE);
4843 log_write(0, LOG_MAIN|LOG_REJECT, "too many recipients: message "
4844 "rejected: sender=<%s> %s", sender_address, host_and_ident(TRUE));
4849 smtp_printf("452 too many recipients\r\n", FALSE);
4851 log_write(0, LOG_MAIN|LOG_REJECT, "too many recipients: excess "
4852 "temporarily rejected: sender=<%s> %s", sender_address,
4853 host_and_ident(TRUE));
4860 /* If we have passed the threshold for rate limiting, apply the current
4861 delay, and update it for next time, provided this is a limited host. */
4863 if (rcpt_count > smtp_rlr_threshold &&
4864 verify_check_host(&smtp_ratelimit_hosts) == OK)
4866 DEBUG(D_receive) debug_printf("rate limit RCPT: delay %.3g sec\n",
4867 smtp_delay_rcpt/1000.0);
4868 millisleep((int)smtp_delay_rcpt);
4869 smtp_delay_rcpt *= smtp_rlr_factor;
4870 if (smtp_delay_rcpt > (double)smtp_rlr_limit)
4871 smtp_delay_rcpt = (double)smtp_rlr_limit;
4874 /* If the MAIL ACL discarded all the recipients, we bypass ACL checking
4875 for them. Otherwise, check the access control list for this recipient. As
4876 there may be a delay in this, re-check for a synchronization error
4877 afterwards, unless pipelining was advertised. */
4879 if (f.recipients_discarded)
4882 if ( (rc = acl_check(ACL_WHERE_RCPT, recipient, acl_smtp_rcpt, &user_msg,
4884 && !f.smtp_in_pipelining_advertised && !check_sync())
4887 /* The ACL was happy */
4891 BOOL more = pipeline_response();
4894 smtp_user_msg(US"250", user_msg);
4896 smtp_printf("250 Accepted\r\n", more);
4897 receive_add_recipient(recipient, -1);
4899 /* Set the dsn flags in the recipients_list */
4900 recipients_list[recipients_count-1].orcpt = orcpt;
4901 recipients_list[recipients_count-1].dsn_flags = dsn_flags;
4903 /* DEBUG(D_receive) debug_printf("DSN: orcpt: %s flags: %d\n",
4904 recipients_list[recipients_count-1].orcpt,
4905 recipients_list[recipients_count-1].dsn_flags); */
4908 /* The recipient was discarded */
4910 else if (rc == DISCARD)
4913 smtp_user_msg(US"250", user_msg);
4915 smtp_printf("250 Accepted\r\n", FALSE);
4918 log_write(0, LOG_MAIN|LOG_REJECT, "%s F=<%s> RCPT %s: "
4919 "discarded by %s ACL%s%s", host_and_ident(TRUE),
4920 sender_address_unrewritten ? sender_address_unrewritten : sender_address,
4921 smtp_cmd_argument, f.recipients_discarded ? "MAIL" : "RCPT",
4922 log_msg ? US": " : US"", log_msg ? log_msg : US"");
4925 /* Either the ACL failed the address, or it was deferred. */
4929 if (rc == FAIL) rcpt_fail_count++; else rcpt_defer_count++;
4930 done = smtp_handle_acl_fail(ACL_WHERE_RCPT, rc, user_msg, log_msg);
4935 /* The DATA command is legal only if it follows successful MAIL FROM
4936 and RCPT TO commands. However, if pipelining is advertised, a bad DATA is
4937 not counted as a protocol error if it follows RCPT (which must have been
4938 rejected if there are no recipients.) This function is complete when a
4939 valid DATA command is encountered.
4941 Note concerning the code used: RFC 2821 says this:
4943 - If there was no MAIL, or no RCPT, command, or all such commands
4944 were rejected, the server MAY return a "command out of sequence"
4945 (503) or "no valid recipients" (554) reply in response to the
4948 The example in the pipelining RFC 2920 uses 554, but I use 503 here
4949 because it is the same whether pipelining is in use or not.
4951 If all the RCPT commands that precede DATA provoked the same error message
4952 (often indicating some kind of system error), it is helpful to include it
4953 with the DATA rejection (an idea suggested by Tony Finch). */
4960 if (chunking_state != CHUNKING_OFFERED)
4962 done = synprot_error(L_smtp_protocol_error, 503, NULL,
4963 US"BDAT command used when CHUNKING not advertised");
4967 /* grab size, endmarker */
4969 if (sscanf(CS smtp_cmd_data, "%u %n", &chunking_datasize, &n) < 1)
4971 done = synprot_error(L_smtp_protocol_error, 501, NULL,
4972 US"missing size for BDAT command");
4975 chunking_state = strcmpic(smtp_cmd_data+n, US"LAST") == 0
4976 ? CHUNKING_LAST : CHUNKING_ACTIVE;
4977 chunking_data_left = chunking_datasize;
4978 DEBUG(D_receive) debug_printf("chunking state %d, %d bytes\n",
4979 (int)chunking_state, chunking_data_left);
4981 f.bdat_readers_wanted = TRUE; /* FIXME: redundant vs chunking_state? */
4990 f.bdat_readers_wanted = FALSE;
4992 DATA_BDAT: /* Common code for DATA and BDAT */
4993 #ifndef DISABLE_PIPE_CONNECT
4994 fl.pipe_connect_acceptable = FALSE;
4996 if (!discarded && recipients_count <= 0)
4998 if (fl.rcpt_smtp_response_same && rcpt_smtp_response)
5000 uschar *code = US"503";
5001 int len = Ustrlen(rcpt_smtp_response);
5002 smtp_respond(code, 3, FALSE, US"All RCPT commands were rejected with "
5004 /* Responses from smtp_printf() will have \r\n on the end */
5005 if (len > 2 && rcpt_smtp_response[len-2] == '\r')
5006 rcpt_smtp_response[len-2] = 0;
5007 smtp_respond(code, 3, FALSE, rcpt_smtp_response);
5009 if (f.smtp_in_pipelining_advertised && last_was_rcpt)
5010 smtp_printf("503 Valid RCPT command must precede %s\r\n", FALSE,
5011 smtp_names[smtp_connection_had[SMTP_HBUFF_PREV(smtp_ch_index)]]);
5013 done = synprot_error(L_smtp_protocol_error, 503, NULL,
5014 smtp_connection_had[SMTP_HBUFF_PREV(smtp_ch_index)] == SCH_DATA
5015 ? US"valid RCPT command must precede DATA"
5016 : US"valid RCPT command must precede BDAT");
5018 if (chunking_state > CHUNKING_OFFERED)
5020 bdat_push_receive_functions();
5026 if (toomany && recipients_max_reject)
5028 sender_address = NULL; /* This will allow a new MAIL without RSET */
5029 sender_address_unrewritten = NULL;
5030 smtp_printf("554 Too many recipients\r\n", FALSE);
5032 if (chunking_state > CHUNKING_OFFERED)
5034 bdat_push_receive_functions();
5040 if (chunking_state > CHUNKING_OFFERED)
5041 rc = OK; /* No predata ACL or go-ahead output for BDAT */
5044 /* If there is an ACL, re-check the synchronization afterwards, since the
5045 ACL may have delayed. To handle cutthrough delivery enforce a dummy call
5046 to get the DATA command sent. */
5048 if (!acl_smtp_predata && cutthrough.cctx.sock < 0)
5052 uschar * acl = acl_smtp_predata ? acl_smtp_predata : US"accept";
5053 f.enable_dollar_recipients = TRUE;
5054 rc = acl_check(ACL_WHERE_PREDATA, NULL, acl, &user_msg,
5056 f.enable_dollar_recipients = FALSE;
5057 if (rc == OK && !check_sync())
5061 { /* Either the ACL failed the address, or it was deferred. */
5062 done = smtp_handle_acl_fail(ACL_WHERE_PREDATA, rc, user_msg, log_msg);
5068 smtp_user_msg(US"354", user_msg);
5071 "354 Enter message, ending with \".\" on a line by itself\r\n", FALSE);
5074 if (f.bdat_readers_wanted)
5075 bdat_push_receive_functions();
5078 if (smtp_in) /* all ACKs needed to ramp window up for bulk data */
5079 (void) setsockopt(fileno(smtp_in), IPPROTO_TCP, TCP_QUICKACK,
5080 US &on, sizeof(on));
5083 message_ended = END_NOTENDED; /* Indicate in middle of data */
5094 if (!(address = parse_extract_address(smtp_cmd_data, &errmess,
5095 &start, &end, &recipient_domain, FALSE)))
5097 smtp_printf("501 %s\r\n", FALSE, errmess);
5101 if (!recipient_domain)
5102 if (!(recipient_domain = qualify_recipient(&address, smtp_cmd_data,
5106 if ((rc = acl_check(ACL_WHERE_VRFY, address, acl_smtp_vrfy,
5107 &user_msg, &log_msg)) != OK)
5108 done = smtp_handle_acl_fail(ACL_WHERE_VRFY, rc, user_msg, log_msg);
5112 address_item * addr = deliver_make_addr(address, FALSE);
5114 switch(verify_address(addr, NULL, vopt_is_recipient | vopt_qualify, -1,
5115 -1, -1, NULL, NULL, NULL))
5118 s = string_sprintf("250 <%s> is deliverable", address);
5122 s = (addr->user_message != NULL)?
5123 string_sprintf("451 <%s> %s", address, addr->user_message) :
5124 string_sprintf("451 Cannot resolve <%s> at this time", address);
5128 s = (addr->user_message != NULL)?
5129 string_sprintf("550 <%s> %s", address, addr->user_message) :
5130 string_sprintf("550 <%s> is not deliverable", address);
5131 log_write(0, LOG_MAIN, "VRFY failed for %s %s",
5132 smtp_cmd_argument, host_and_ident(TRUE));
5136 smtp_printf("%s\r\n", FALSE, s);
5144 rc = acl_check(ACL_WHERE_EXPN, NULL, acl_smtp_expn, &user_msg, &log_msg);
5146 done = smtp_handle_acl_fail(ACL_WHERE_EXPN, rc, user_msg, log_msg);
5149 BOOL save_log_testing_mode = f.log_testing_mode;
5150 f.address_test_mode = f.log_testing_mode = TRUE;
5151 (void) verify_address(deliver_make_addr(smtp_cmd_data, FALSE),
5152 smtp_out, vopt_is_recipient | vopt_qualify | vopt_expn, -1, -1, -1,
5154 f.address_test_mode = FALSE;
5155 f.log_testing_mode = save_log_testing_mode; /* true for -bh */
5164 if (!fl.tls_advertised)
5166 done = synprot_error(L_smtp_protocol_error, 503, NULL,
5167 US"STARTTLS command used when not advertised");
5171 /* Apply an ACL check if one is defined */
5173 if ( acl_smtp_starttls
5174 && (rc = acl_check(ACL_WHERE_STARTTLS, NULL, acl_smtp_starttls,
5175 &user_msg, &log_msg)) != OK
5178 done = smtp_handle_acl_fail(ACL_WHERE_STARTTLS, rc, user_msg, log_msg);
5182 /* RFC 2487 is not clear on when this command may be sent, though it
5183 does state that all information previously obtained from the client
5184 must be discarded if a TLS session is started. It seems reasonable to
5185 do an implied RSET when STARTTLS is received. */
5187 incomplete_transaction_log(US"STARTTLS");
5188 cancel_cutthrough_connection(TRUE, US"STARTTLS received");
5189 reset_point = smtp_reset(reset_point);
5191 cmd_list[CL_STLS].is_mail_cmd = FALSE;
5193 /* There's an attack where more data is read in past the STARTTLS command
5194 before TLS is negotiated, then assumed to be part of the secure session
5195 when used afterwards; we use segregated input buffers, so are not
5196 vulnerable, but we want to note when it happens and, for sheer paranoia,
5197 ensure that the buffer is "wiped".
5198 Pipelining sync checks will normally have protected us too, unless disabled
5199 by configuration. */
5204 debug_printf("Non-empty input buffer after STARTTLS; naive attack?\n");
5205 if (tls_in.active.sock < 0)
5206 smtp_inend = smtp_inptr = smtp_inbuffer;
5207 /* and if TLS is already active, tls_server_start() should fail */
5210 /* There is nothing we value in the input buffer and if TLS is successfully
5211 negotiated, we won't use this buffer again; if TLS fails, we'll just read
5212 fresh content into it. The buffer contains arbitrary content from an
5213 untrusted remote source; eg: NOOP <shellcode>\r\nSTARTTLS\r\n
5214 It seems safest to just wipe away the content rather than leave it as a
5215 target to jump to. */
5217 memset(smtp_inbuffer, 0, IN_BUFFER_SIZE);
5219 /* Attempt to start up a TLS session, and if successful, discard all
5220 knowledge that was obtained previously. At least, that's what the RFC says,
5221 and that's what happens by default. However, in order to work round YAEB,
5222 there is an option to remember the esmtp state. Sigh.
5224 We must allow for an extra EHLO command and an extra AUTH command after
5225 STARTTLS that don't add to the nonmail command count. */
5228 if ((rc = tls_server_start(&s)) == OK)
5230 if (!tls_remember_esmtp)
5231 fl.helo_seen = fl.esmtp = fl.auth_advertised = f.smtp_in_pipelining_advertised = FALSE;
5232 cmd_list[CL_EHLO].is_mail_cmd = TRUE;
5233 cmd_list[CL_AUTH].is_mail_cmd = TRUE;
5234 cmd_list[CL_TLAU].is_mail_cmd = TRUE;
5235 if (sender_helo_name)
5237 sender_helo_name = NULL;
5238 host_build_sender_fullhost(); /* Rebuild */
5239 set_process_info("handling incoming TLS connection from %s",
5240 host_and_ident(FALSE));
5243 (sender_host_address ? protocols : protocols_local)
5245 ? pextend + (sender_host_authenticated ? pauthed : 0)
5247 + (tls_in.active.sock >= 0 ? pcrpted : 0)
5250 sender_host_auth_pubname = sender_host_authenticated = NULL;
5251 authenticated_id = NULL;
5252 sync_cmd_limit = NON_SYNC_CMD_NON_PIPELINING;
5253 DEBUG(D_tls) debug_printf("TLS active\n");
5254 break; /* Successful STARTTLS */
5257 (void) smtp_log_tls_fail(s);
5259 /* Some local configuration problem was discovered before actually trying
5260 to do a TLS handshake; give a temporary error. */
5264 smtp_printf("454 TLS currently unavailable\r\n", FALSE);
5268 /* Hard failure. Reject everything except QUIT or closed connection. One
5269 cause for failure is a nested STARTTLS, in which case tls_in.active remains
5270 set, but we must still reject all incoming commands. Another is a handshake
5271 failure - and there may some encrypted data still in the pipe to us, which we
5272 see as garbage commands. */
5274 DEBUG(D_tls) debug_printf("TLS failed to start\n");
5275 while (done <= 0) switch(smtp_read_command(FALSE, GETC_BUFFER_UNLIMITED))
5278 log_close_event(US"by EOF");
5279 smtp_notquit_exit(US"tls-failed", NULL, NULL);
5283 /* It is perhaps arguable as to which exit ACL should be called here,
5284 but as it is probably a situation that almost never arises, it
5285 probably doesn't matter. We choose to call the real QUIT ACL, which in
5286 some sense is perhaps "right". */
5289 f.smtp_in_quit = TRUE;
5292 && ((rc = acl_check(ACL_WHERE_QUIT, NULL, acl_smtp_quit, &user_msg,
5293 &log_msg)) == ERROR))
5294 log_write(0, LOG_MAIN|LOG_PANIC, "ACL for QUIT returned ERROR: %s",
5297 smtp_respond(US"221", 3, TRUE, user_msg);
5299 smtp_printf("221 %s closing connection\r\n", FALSE, smtp_active_hostname);
5300 log_close_event(US"by QUIT");
5305 smtp_printf("554 Security failure\r\n", FALSE);
5308 tls_close(NULL, TLS_SHUTDOWN_NOWAIT);
5313 /* The ACL for QUIT is provided for gathering statistical information or
5314 similar; it does not affect the response code, but it can supply a custom
5318 smtp_quit_handler(&user_msg, &log_msg);
5324 smtp_rset_handler();
5325 cancel_cutthrough_connection(TRUE, US"RSET received");
5326 reset_point = smtp_reset(reset_point);
5333 smtp_printf("250 OK\r\n", FALSE);
5337 /* Show ETRN/EXPN/VRFY if there's an ACL for checking hosts; if actually
5338 used, a check will be done for permitted hosts. Show STARTTLS only if not
5339 already in a TLS session and if it would be advertised in the EHLO
5344 smtp_printf("214-Commands supported:\r\n214", TRUE);
5345 smtp_printf(" AUTH", TRUE);
5347 if (tls_in.active.sock < 0 &&
5348 verify_check_host(&tls_advertise_hosts) != FAIL)
5349 smtp_printf(" STARTTLS", TRUE);
5351 smtp_printf(" HELO EHLO MAIL RCPT DATA BDAT", TRUE);
5352 smtp_printf(" NOOP QUIT RSET HELP", TRUE);
5353 if (acl_smtp_etrn) smtp_printf(" ETRN", TRUE);
5354 if (acl_smtp_expn) smtp_printf(" EXPN", TRUE);
5355 if (acl_smtp_vrfy) smtp_printf(" VRFY", TRUE);
5356 smtp_printf("\r\n", FALSE);
5361 incomplete_transaction_log(US"connection lost");
5362 smtp_notquit_exit(US"connection-lost", US"421",
5363 US"%s lost input connection", smtp_active_hostname);
5365 /* Don't log by default unless in the middle of a message, as some mailers
5366 just drop the call rather than sending QUIT, and it clutters up the logs.
5369 if (sender_address || recipients_count > 0)
5370 log_write(L_lost_incoming_connection, LOG_MAIN,
5371 "unexpected %s while reading SMTP command from %s%s%s D=%s",
5372 f.sender_host_unknown ? "EOF" : "disconnection",
5373 f.tcp_in_fastopen_logged
5376 ? f.tcp_in_fastopen_data ? US"TFO* " : US"TFO "
5378 host_and_ident(FALSE), smtp_read_error,
5379 string_timesince(&smtp_connection_start)
5383 log_write(L_smtp_connection, LOG_MAIN, "%s %slost%s D=%s",
5384 smtp_get_connection_info(),
5385 f.tcp_in_fastopen && !f.tcp_in_fastopen_logged ? US"TFO " : US"",
5387 string_timesince(&smtp_connection_start)
5398 done = synprot_error(L_smtp_protocol_error, 503, NULL,
5399 US"ETRN is not permitted inside a transaction");
5403 log_write(L_etrn, LOG_MAIN, "ETRN %s received from %s", smtp_cmd_argument,
5404 host_and_ident(FALSE));
5406 if ((rc = acl_check(ACL_WHERE_ETRN, NULL, acl_smtp_etrn,
5407 &user_msg, &log_msg)) != OK)
5409 done = smtp_handle_acl_fail(ACL_WHERE_ETRN, rc, user_msg, log_msg);
5413 /* Compute the serialization key for this command. */
5415 etrn_serialize_key = string_sprintf("etrn-%s\n", smtp_cmd_data);
5417 /* If a command has been specified for running as a result of ETRN, we
5418 permit any argument to ETRN. If not, only the # standard form is permitted,
5419 since that is strictly the only kind of ETRN that can be implemented
5420 according to the RFC. */
5422 if (smtp_etrn_command)
5426 etrn_command = smtp_etrn_command;
5427 deliver_domain = smtp_cmd_data;
5428 rc = transport_set_up_command(&argv, smtp_etrn_command, TRUE, 0, NULL,
5429 FALSE, US"ETRN processing", &error);
5430 deliver_domain = NULL;
5433 log_write(0, LOG_MAIN|LOG_PANIC, "failed to set up ETRN command: %s",
5435 smtp_printf("458 Internal failure\r\n", FALSE);
5440 /* Else set up to call Exim with the -R option. */
5444 if (*smtp_cmd_data++ != '#')
5446 done = synprot_error(L_smtp_syntax_error, 501, NULL,
5447 US"argument must begin with #");
5450 etrn_command = US"exim -R";
5451 argv = CUSS child_exec_exim(CEE_RETURN_ARGV, TRUE, NULL, TRUE,
5452 *queue_name ? 4 : 2,
5453 US"-R", smtp_cmd_data,
5454 US"-MCG", queue_name);
5457 /* If we are host-testing, don't actually do anything. */
5463 debug_printf("ETRN command is: %s\n", etrn_command);
5464 debug_printf("ETRN command execution skipped\n");
5466 if (user_msg == NULL) smtp_printf("250 OK\r\n", FALSE);
5467 else smtp_user_msg(US"250", user_msg);
5472 /* If ETRN queue runs are to be serialized, check the database to
5473 ensure one isn't already running. */
5475 if (smtp_etrn_serialize && !enq_start(etrn_serialize_key, 1))
5477 smtp_printf("458 Already processing %s\r\n", FALSE, smtp_cmd_data);
5481 /* Fork a child process and run the command. We don't want to have to
5482 wait for the process at any point, so set SIGCHLD to SIG_IGN before
5483 forking. It should be set that way anyway for external incoming SMTP,
5484 but we save and restore to be tidy. If serialization is required, we
5485 actually run the command in yet another process, so we can wait for it
5486 to complete and then remove the serialization lock. */
5488 oldsignal = signal(SIGCHLD, SIG_IGN);
5490 if ((pid = exim_fork(US"etrn-command")) == 0)
5492 smtp_input = FALSE; /* This process is not associated with the */
5493 (void)fclose(smtp_in); /* SMTP call any more. */
5494 (void)fclose(smtp_out);
5496 signal(SIGCHLD, SIG_DFL); /* Want to catch child */
5498 /* If not serializing, do the exec right away. Otherwise, fork down
5499 into another process. */
5501 if ( !smtp_etrn_serialize
5502 || (pid = exim_fork(US"etrn-serialised-command")) == 0)
5504 DEBUG(D_exec) debug_print_argv(argv);
5505 exim_nullstd(); /* Ensure std{in,out,err} exist */
5506 /* argv[0] should be untainted, from child_exec_exim() */
5507 execv(CS argv[0], (char *const *)argv);
5508 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "exec of \"%s\" (ETRN) failed: %s",
5509 etrn_command, strerror(errno));
5510 _exit(EXIT_FAILURE); /* paranoia */
5513 /* Obey this if smtp_serialize and the 2nd fork yielded non-zero. That
5514 is, we are in the first subprocess, after forking again. All we can do
5515 for a failing fork is to log it. Otherwise, wait for the 2nd process to
5516 complete, before removing the serialization. */
5519 log_write(0, LOG_MAIN|LOG_PANIC, "2nd fork for serialized ETRN "
5520 "failed: %s", strerror(errno));
5524 DEBUG(D_any) debug_printf("waiting for serialized ETRN process %d\n",
5526 (void)wait(&status);
5527 DEBUG(D_any) debug_printf("serialized ETRN process %d ended\n",
5531 enq_end(etrn_serialize_key);
5532 exim_underbar_exit(EXIT_SUCCESS);
5535 /* Back in the top level SMTP process. Check that we started a subprocess
5536 and restore the signal state. */
5540 log_write(0, LOG_MAIN|LOG_PANIC, "fork of process for ETRN failed: %s",
5542 smtp_printf("458 Unable to fork process\r\n", FALSE);
5543 if (smtp_etrn_serialize) enq_end(etrn_serialize_key);
5547 smtp_printf("250 OK\r\n", FALSE);
5549 smtp_user_msg(US"250", user_msg);
5551 signal(SIGCHLD, oldsignal);
5556 done = synprot_error(L_smtp_syntax_error, 501, NULL,
5557 US"unexpected argument data");
5561 /* This currently happens only for NULLs, but could be extended. */
5564 done = synprot_error(L_smtp_syntax_error, 0, NULL, /* Just logs */
5565 US"NUL character(s) present (shown as '?')");
5566 smtp_printf("501 NUL characters are not allowed in SMTP commands\r\n",
5573 if (smtp_inend >= smtp_inbuffer + IN_BUFFER_SIZE)
5574 smtp_inend = smtp_inbuffer + IN_BUFFER_SIZE - 1;
5575 c = smtp_inend - smtp_inptr;
5576 if (c > 150) c = 150; /* limit logged amount */
5578 incomplete_transaction_log(US"sync failure");
5579 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP protocol synchronization error "
5580 "(next input sent too soon: pipelining was%s advertised): "
5581 "rejected \"%s\" %s next input=\"%s\"",
5582 f.smtp_in_pipelining_advertised ? "" : " not",
5583 smtp_cmd_buffer, host_and_ident(TRUE),
5584 string_printing(smtp_inptr));
5585 smtp_notquit_exit(US"synchronization-error", US"554",
5586 US"SMTP synchronization error");
5587 done = 1; /* Pretend eof - drops connection */
5591 case TOO_MANY_NONMAIL_CMD:
5592 s = smtp_cmd_buffer;
5593 while (*s != 0 && !isspace(*s)) s++;
5594 incomplete_transaction_log(US"too many non-mail commands");
5595 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
5596 "nonmail commands (last was \"%.*s\")", host_and_ident(FALSE),
5597 (int)(s - smtp_cmd_buffer), smtp_cmd_buffer);
5598 smtp_notquit_exit(US"bad-commands", US"554", US"Too many nonmail commands");
5599 done = 1; /* Pretend eof - drops connection */
5602 #ifdef SUPPORT_PROXY
5603 case PROXY_FAIL_IGNORE_CMD:
5604 smtp_printf("503 Command refused, required Proxy negotiation failed\r\n", FALSE);
5609 if (unknown_command_count++ >= smtp_max_unknown_commands)
5611 log_write(L_smtp_syntax_error, LOG_MAIN,
5612 "SMTP syntax error in \"%s\" %s %s",
5613 string_printing(smtp_cmd_buffer), host_and_ident(TRUE),
5614 US"unrecognized command");
5615 incomplete_transaction_log(US"unrecognized command");
5616 smtp_notquit_exit(US"bad-commands", US"500",
5617 US"Too many unrecognized commands");
5619 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
5620 "unrecognized commands (last was \"%s\")", host_and_ident(FALSE),
5621 string_printing(smtp_cmd_buffer));
5624 done = synprot_error(L_smtp_syntax_error, 500, NULL,
5625 US"unrecognized command");
5629 /* This label is used by goto's inside loops that want to break out to
5630 the end of the command-processing loop. */
5633 last_was_rej_mail = was_rej_mail; /* Remember some last commands for */
5634 last_was_rcpt = was_rcpt; /* protocol error handling */
5637 return done - 2; /* Convert yield values */
5643 authres_smtpauth(gstring * g)
5645 if (!sender_host_authenticated)
5648 g = string_append(g, 2, US";\n\tauth=pass (", sender_host_auth_pubname);
5650 if (Ustrcmp(sender_host_auth_pubname, "tls") == 0)
5651 g = authenticated_id
5652 ? string_append(g, 2, US") x509.auth=", authenticated_id)
5653 : string_cat(g, US") reason=x509.auth");
5655 g = authenticated_id
5656 ? string_append(g, 2, US") smtp.auth=", authenticated_id)
5657 : string_cat(g, US", no id saved)");
5659 if (authenticated_sender)
5660 g = string_append(g, 2, US" smtp.mailfrom=", authenticated_sender);
5668 /* End of smtp_in.c */