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 #ifdef SUPPORT_PROXY
1114 /*************************************************
1115 * Check if host is required proxy host *
1116 *************************************************/
1117 /* The function determines if inbound host will be a regular smtp host
1118 or if it is configured that it must use Proxy Protocol. A local
1126 check_proxy_protocol_host()
1130 if ( sender_host_address
1131 && (rc = verify_check_this_host(CUSS &hosts_proxy, NULL, NULL,
1132 sender_host_address, NULL)) == OK)
1135 debug_printf("Detected proxy protocol configured host\n");
1136 proxy_session = TRUE;
1138 return proxy_session;
1142 /*************************************************
1143 * Read data until newline or end of buffer *
1144 *************************************************/
1145 /* While SMTP is server-speaks-first, TLS is client-speaks-first, so we can't
1146 read an entire buffer and assume there will be nothing past a proxy protocol
1147 header. Our approach normally is to use stdio, but again that relies upon
1148 "STARTTLS\r\n" and a server response before the client starts TLS handshake, or
1149 reading _nothing_ before client TLS handshake. So we don't want to use the
1150 usual buffering reads which may read enough to block TLS starting.
1152 So unfortunately we're down to "read one byte at a time, with a syscall each,
1153 and expect a little overhead", for all proxy-opened connections which are v1,
1154 just to handle the TLS-on-connect case. Since SSL functions wrap the
1155 underlying fd, we can't assume that we can feed them any already-read content.
1157 We need to know where to read to, the max capacity, and we'll read until we
1158 get a CR and one more character. Let the caller scream if it's CR+!LF.
1160 Return the amount read.
1164 swallow_until_crlf(int fd, uschar *base, int already, int capacity)
1166 uschar *to = base + already;
1172 /* For "PROXY UNKNOWN\r\n" we, at time of writing, expect to have read
1173 up through the \r; for the _normal_ case, we haven't yet seen the \r. */
1175 cr = memchr(base, '\r', already);
1178 if ((cr - base) < already - 1)
1180 /* \r and presumed \n already within what we have; probably not
1181 actually proxy protocol, but abort cleanly. */
1184 /* \r is last character read, just need one more. */
1188 while (capacity > 0)
1190 do { ret = read(fd, to, 1); } while (ret == -1 && errno == EINTR && !had_command_timeout);
1202 /* reached end without having room for a final newline, abort */
1209 proxy_debug(uschar * buf, unsigned start, unsigned end)
1211 debug_printf("PROXY<<");
1212 while (start < end) debug_printf(" %02x", buf[start++]);
1217 /*************************************************
1218 * Setup host for proxy protocol *
1219 *************************************************/
1220 /* The function configures the connection based on a header from the
1221 inbound host to use Proxy Protocol. The specification is very exact
1222 so exit with an error if do not find the exact required pieces. This
1223 includes an incorrect number of spaces separating args.
1226 Returns: Boolean success
1230 setup_proxy_protocol_host()
1242 struct { /* TCP/UDP over IPv4, len = 12 */
1248 struct { /* TCP/UDP over IPv6, len = 36 */
1249 uint8_t src_addr[16];
1250 uint8_t dst_addr[16];
1254 struct { /* AF_UNIX sockets, len = 216 */
1255 uschar src_addr[108];
1256 uschar dst_addr[108];
1262 /* Temp variables used in PPv2 address:port parsing */
1264 char tmpip[INET_ADDRSTRLEN];
1265 struct sockaddr_in tmpaddr;
1266 char tmpip6[INET6_ADDRSTRLEN];
1267 struct sockaddr_in6 tmpaddr6;
1269 /* We can't read "all data until end" because while SMTP is
1270 server-speaks-first, the TLS handshake is client-speaks-first, so for
1271 TLS-on-connect ports the proxy protocol header will usually be immediately
1272 followed by a TLS handshake, and with N TLS libraries, we can't reliably
1273 reinject data for reading by those. So instead we first read "enough to be
1274 safely read within the header, and figure out how much more to read".
1275 For v1 we will later read to the end-of-line, for v2 we will read based upon
1278 The v2 sig is 12 octets, and another 4 gets us the length, so we know how much
1279 data is needed total. For v1, where the line looks like:
1280 PROXY TCPn L3src L3dest SrcPort DestPort \r\n
1282 However, for v1 there's also `PROXY UNKNOWN\r\n` which is only 15 octets.
1283 We seem to support that. So, if we read 14 octets then we can tell if we're
1284 v2 or v1. If we're v1, we can continue reading as normal.
1286 If we're v2, we can't slurp up the entire header. We need the length in the
1287 15th & 16th octets, then to read everything after that.
1289 So to safely handle v1 and v2, with client-sent-first supported correctly,
1290 we have to do a minimum of 3 read calls, not 1. Eww.
1293 # define PROXY_INITIAL_READ 14
1294 # define PROXY_V2_HEADER_SIZE 16
1295 # if PROXY_INITIAL_READ > PROXY_V2_HEADER_SIZE
1296 # error Code bug in sizes of data to read for proxy usage
1301 int fd = fileno(smtp_in);
1302 const char v2sig[12] = "\x0D\x0A\x0D\x0A\x00\x0D\x0A\x51\x55\x49\x54\x0A";
1303 uschar * iptype; /* To display debug info */
1304 socklen_t vslen = sizeof(struct timeval);
1307 os_non_restarting_signal(SIGALRM, command_timeout_handler);
1308 ALARM(proxy_protocol_timeout);
1312 /* The inbound host was declared to be a Proxy Protocol host, so
1313 don't do a PEEK into the data, actually slurp up enough to be
1314 "safe". Can't take it all because TLS-on-connect clients follow
1315 immediately with TLS handshake. */
1316 ret = read(fd, &hdr, PROXY_INITIAL_READ);
1317 } while (ret == -1 && errno == EINTR && !had_command_timeout);
1321 DEBUG(D_receive) proxy_debug(US &hdr, 0, ret);
1323 /* For v2, handle reading the length, and then the rest. */
1324 if ((ret == PROXY_INITIAL_READ) && (memcmp(&hdr.v2, v2sig, sizeof(v2sig)) == 0))
1329 DEBUG(D_receive) debug_printf("v2\n");
1331 /* First get the length fields. */
1334 retmore = read(fd, (uschar*)&hdr + ret, PROXY_V2_HEADER_SIZE - PROXY_INITIAL_READ);
1335 } while (retmore == -1 && errno == EINTR && !had_command_timeout);
1338 DEBUG(D_receive) proxy_debug(US &hdr, ret, ret + retmore);
1342 ver = (hdr.v2.ver_cmd & 0xf0) >> 4;
1344 /* May 2014: haproxy combined the version and command into one byte to
1345 allow two full bytes for the length field in order to proxy SSL
1346 connections. SSL Proxy is not supported in this version of Exim, but
1347 must still separate values here. */
1351 DEBUG(D_receive) debug_printf("Invalid Proxy Protocol version: %d\n", ver);
1355 /* The v2 header will always be 16 bytes per the spec. */
1356 size = 16 + ntohs(hdr.v2.len);
1357 DEBUG(D_receive) debug_printf("Detected PROXYv2 header, size %d (limit %d)\n",
1358 size, (int)sizeof(hdr));
1360 /* We should now have 16 octets (PROXY_V2_HEADER_SIZE), and we know the total
1361 amount that we need. Double-check that the size is not unreasonable, then
1363 if (size > sizeof(hdr))
1365 DEBUG(D_receive) debug_printf("PROXYv2 header size unreasonably large; security attack?\n");
1373 retmore = read(fd, (uschar*)&hdr + ret, size-ret);
1374 } while (retmore == -1 && errno == EINTR && !had_command_timeout);
1377 DEBUG(D_receive) proxy_debug(US &hdr, ret, ret + retmore);
1379 DEBUG(D_receive) debug_printf("PROXYv2: have %d/%d required octets\n", ret, size);
1380 } while (ret < size);
1382 } /* end scope for getting rest of data for v2 */
1384 /* At this point: if PROXYv2, we've read the exact size required for all data;
1385 if PROXYv1 then we've read "less than required for any valid line" and should
1388 if (ret >= 16 && memcmp(&hdr.v2, v2sig, 12) == 0)
1390 uint8_t cmd = (hdr.v2.ver_cmd & 0x0f);
1394 case 0x01: /* PROXY command */
1397 case 0x11: /* TCPv4 address type */
1399 tmpaddr.sin_addr.s_addr = hdr.v2.addr.ip4.src_addr;
1400 inet_ntop(AF_INET, &tmpaddr.sin_addr, CS &tmpip, sizeof(tmpip));
1401 if (!string_is_ip_address(US tmpip, NULL))
1403 DEBUG(D_receive) debug_printf("Invalid %s source IP\n", iptype);
1406 proxy_local_address = sender_host_address;
1407 sender_host_address = string_copy(US tmpip);
1408 tmpport = ntohs(hdr.v2.addr.ip4.src_port);
1409 proxy_local_port = sender_host_port;
1410 sender_host_port = tmpport;
1411 /* Save dest ip/port */
1412 tmpaddr.sin_addr.s_addr = hdr.v2.addr.ip4.dst_addr;
1413 inet_ntop(AF_INET, &tmpaddr.sin_addr, CS &tmpip, sizeof(tmpip));
1414 if (!string_is_ip_address(US tmpip, NULL))
1416 DEBUG(D_receive) debug_printf("Invalid %s dest port\n", iptype);
1419 proxy_external_address = string_copy(US tmpip);
1420 tmpport = ntohs(hdr.v2.addr.ip4.dst_port);
1421 proxy_external_port = tmpport;
1423 case 0x21: /* TCPv6 address type */
1425 memmove(tmpaddr6.sin6_addr.s6_addr, hdr.v2.addr.ip6.src_addr, 16);
1426 inet_ntop(AF_INET6, &tmpaddr6.sin6_addr, CS &tmpip6, sizeof(tmpip6));
1427 if (!string_is_ip_address(US tmpip6, NULL))
1429 DEBUG(D_receive) debug_printf("Invalid %s source IP\n", iptype);
1432 proxy_local_address = sender_host_address;
1433 sender_host_address = string_copy(US tmpip6);
1434 tmpport = ntohs(hdr.v2.addr.ip6.src_port);
1435 proxy_local_port = sender_host_port;
1436 sender_host_port = tmpport;
1437 /* Save dest ip/port */
1438 memmove(tmpaddr6.sin6_addr.s6_addr, hdr.v2.addr.ip6.dst_addr, 16);
1439 inet_ntop(AF_INET6, &tmpaddr6.sin6_addr, CS &tmpip6, sizeof(tmpip6));
1440 if (!string_is_ip_address(US tmpip6, NULL))
1442 DEBUG(D_receive) debug_printf("Invalid %s dest port\n", iptype);
1445 proxy_external_address = string_copy(US tmpip6);
1446 tmpport = ntohs(hdr.v2.addr.ip6.dst_port);
1447 proxy_external_port = tmpport;
1451 debug_printf("Unsupported PROXYv2 connection type: 0x%02x\n",
1455 /* Unsupported protocol, keep local connection address */
1457 case 0x00: /* LOCAL command */
1458 /* Keep local connection address for LOCAL */
1463 debug_printf("Unsupported PROXYv2 command: 0x%x\n", cmd);
1467 else if (ret >= 8 && memcmp(hdr.v1.line, "PROXY", 5) == 0)
1471 uschar *sp; /* Utility variables follow */
1476 /* get the rest of the line */
1477 r2 = swallow_until_crlf(fd, (uschar*)&hdr, ret, sizeof(hdr)-ret);
1482 p = string_copy(hdr.v1.line);
1483 end = memchr(p, '\r', ret - 1);
1485 if (!end || (end == (uschar*)&hdr + ret) || end[1] != '\n')
1487 DEBUG(D_receive) debug_printf("Partial or invalid PROXY header\n");
1490 *end = '\0'; /* Terminate the string */
1491 size = end + 2 - p; /* Skip header + CRLF */
1492 DEBUG(D_receive) debug_printf("Detected PROXYv1 header\n");
1493 DEBUG(D_receive) debug_printf("Bytes read not within PROXY header: %d\n", ret - size);
1494 /* Step through the string looking for the required fields. Ensure
1495 strict adherence to required formatting, exit for any error. */
1497 if (!isspace(*(p++)))
1499 DEBUG(D_receive) debug_printf("Missing space after PROXY command\n");
1502 if (!Ustrncmp(p, CCS"TCP4", 4))
1504 else if (!Ustrncmp(p,CCS"TCP6", 4))
1506 else if (!Ustrncmp(p,CCS"UNKNOWN", 7))
1508 iptype = US"Unknown";
1513 DEBUG(D_receive) debug_printf("Invalid TCP type\n");
1517 p += Ustrlen(iptype);
1518 if (!isspace(*(p++)))
1520 DEBUG(D_receive) debug_printf("Missing space after TCP4/6 command\n");
1523 /* Find the end of the arg */
1524 if ((sp = Ustrchr(p, ' ')) == NULL)
1527 debug_printf("Did not find proxied src %s\n", iptype);
1531 if(!string_is_ip_address(p, NULL))
1534 debug_printf("Proxied src arg is not an %s address\n", iptype);
1537 proxy_local_address = sender_host_address;
1538 sender_host_address = p;
1540 if ((sp = Ustrchr(p, ' ')) == NULL)
1543 debug_printf("Did not find proxy dest %s\n", iptype);
1547 if(!string_is_ip_address(p, NULL))
1550 debug_printf("Proxy dest arg is not an %s address\n", iptype);
1553 proxy_external_address = p;
1555 if ((sp = Ustrchr(p, ' ')) == NULL)
1557 DEBUG(D_receive) debug_printf("Did not find proxied src port\n");
1561 tmp_port = strtol(CCS p, &endc, 10);
1562 if (*endc || tmp_port == 0)
1565 debug_printf("Proxied src port '%s' not an integer\n", p);
1568 proxy_local_port = sender_host_port;
1569 sender_host_port = tmp_port;
1571 if ((sp = Ustrchr(p, '\0')) == NULL)
1573 DEBUG(D_receive) debug_printf("Did not find proxy dest port\n");
1576 tmp_port = strtol(CCS p, &endc, 10);
1577 if (*endc || tmp_port == 0)
1580 debug_printf("Proxy dest port '%s' not an integer\n", p);
1583 proxy_external_port = tmp_port;
1584 /* Already checked for /r /n above. Good V1 header received. */
1588 /* Wrong protocol */
1589 DEBUG(D_receive) debug_printf("Invalid proxy protocol version negotiation\n");
1590 (void) swallow_until_crlf(fd, (uschar*)&hdr, ret, sizeof(hdr)-ret);
1596 debug_printf("Valid %s sender from Proxy Protocol header\n", iptype);
1597 yield = proxy_session;
1599 /* Don't flush any potential buffer contents. Any input on proxyfail
1600 should cause a synchronization failure */
1603 DEBUG(D_receive) if (had_command_timeout)
1604 debug_printf("Timeout while reading proxy header\n");
1609 sender_host_name = NULL;
1610 (void) host_name_lookup();
1611 host_build_sender_fullhost();
1615 f.proxy_session_failed = TRUE;
1617 debug_printf("Failure to extract proxied host, only QUIT allowed\n");
1623 #endif /*SUPPORT_PROXY*/
1625 /*************************************************
1626 * Read one command line *
1627 *************************************************/
1629 /* Strictly, SMTP commands coming over the net are supposed to end with CRLF.
1630 There are sites that don't do this, and in any case internal SMTP probably
1631 should check only for LF. Consequently, we check here for LF only. The line
1632 ends up with [CR]LF removed from its end. If we get an overlong line, treat as
1633 an unknown command. The command is read into the global smtp_cmd_buffer so that
1634 it is available via $smtp_command.
1636 The character reading routine sets up a timeout for each block actually read
1637 from the input (which may contain more than one command). We set up a special
1638 signal handler that closes down the session on a timeout. Control does not
1639 return when it runs.
1642 check_sync if TRUE, check synchronization rules if global option is TRUE
1643 buffer_lim maximum to buffer in lower layer
1645 Returns: a code identifying the command (enumerated above)
1649 smtp_read_command(BOOL check_sync, unsigned buffer_lim)
1653 BOOL hadnull = FALSE;
1655 had_command_timeout = 0;
1656 os_non_restarting_signal(SIGALRM, command_timeout_handler);
1658 while ((c = (receive_getc)(buffer_lim)) != '\n' && c != EOF)
1660 if (ptr >= SMTP_CMD_BUFFER_SIZE)
1662 os_non_restarting_signal(SIGALRM, sigalrm_handler);
1670 smtp_cmd_buffer[ptr++] = c;
1673 receive_linecount++; /* For BSMTP errors */
1674 os_non_restarting_signal(SIGALRM, sigalrm_handler);
1676 /* If hit end of file, return pseudo EOF command. Whether we have a
1677 part-line already read doesn't matter, since this is an error state. */
1679 if (c == EOF) return EOF_CMD;
1681 /* Remove any CR and white space at the end of the line, and terminate the
1684 while (ptr > 0 && isspace(smtp_cmd_buffer[ptr-1])) ptr--;
1685 smtp_cmd_buffer[ptr] = 0;
1687 DEBUG(D_receive) debug_printf("SMTP<< %s\n", smtp_cmd_buffer);
1689 /* NULLs are not allowed in SMTP commands */
1691 if (hadnull) return BADCHAR_CMD;
1693 /* Scan command list and return identity, having set the data pointer
1694 to the start of the actual data characters. Check for SMTP synchronization
1697 for (smtp_cmd_list * p = cmd_list; p < cmd_list + nelem(cmd_list); p++)
1699 #ifdef SUPPORT_PROXY
1700 /* Only allow QUIT command if Proxy Protocol parsing failed */
1701 if (proxy_session && f.proxy_session_failed && p->cmd != QUIT_CMD)
1705 && strncmpic(smtp_cmd_buffer, US p->name, p->len) == 0
1706 && ( smtp_cmd_buffer[p->len-1] == ':' /* "mail from:" or "rcpt to:" */
1707 || smtp_cmd_buffer[p->len] == 0
1708 || smtp_cmd_buffer[p->len] == ' '
1711 if ( smtp_inptr < smtp_inend /* Outstanding input */
1712 && p->cmd < sync_cmd_limit /* Command should sync */
1713 && check_sync /* Local flag set */
1714 && smtp_enforce_sync /* Global flag set */
1715 && sender_host_address != NULL /* Not local input */
1716 && !f.sender_host_notsocket /* Really is a socket */
1720 /* The variables $smtp_command and $smtp_command_argument point into the
1721 unmodified input buffer. A copy of the latter is taken for actual
1722 processing, so that it can be chopped up into separate parts if necessary,
1723 for example, when processing a MAIL command options such as SIZE that can
1724 follow the sender address. */
1726 smtp_cmd_argument = smtp_cmd_buffer + p->len;
1727 while (isspace(*smtp_cmd_argument)) smtp_cmd_argument++;
1728 Ustrcpy(smtp_data_buffer, smtp_cmd_argument);
1729 smtp_cmd_data = smtp_data_buffer;
1731 /* Count non-mail commands from those hosts that are controlled in this
1732 way. The default is all hosts. We don't waste effort checking the list
1733 until we get a non-mail command, but then cache the result to save checking
1734 again. If there's a DEFER while checking the host, assume it's in the list.
1736 Note that one instance of RSET, EHLO/HELO, and STARTTLS is allowed at the
1737 start of each incoming message by fiddling with the value in the table. */
1739 if (!p->is_mail_cmd)
1741 if (count_nonmail == TRUE_UNSET) count_nonmail =
1742 verify_check_host(&smtp_accept_max_nonmail_hosts) != FAIL;
1743 if (count_nonmail && ++nonmail_command_count > smtp_accept_max_nonmail)
1744 return TOO_MANY_NONMAIL_CMD;
1747 /* If there is data for a command that does not expect it, generate the
1750 return (p->has_arg || *smtp_cmd_data == 0)? p->cmd : BADARG_CMD;
1754 #ifdef SUPPORT_PROXY
1755 /* Only allow QUIT command if Proxy Protocol parsing failed */
1756 if (proxy_session && f.proxy_session_failed)
1757 return PROXY_FAIL_IGNORE_CMD;
1760 /* Enforce synchronization for unknown commands */
1762 if ( smtp_inptr < smtp_inend /* Outstanding input */
1763 && check_sync /* Local flag set */
1764 && smtp_enforce_sync /* Global flag set */
1765 && sender_host_address /* Not local input */
1766 && !f.sender_host_notsocket /* Really is a socket */
1775 /*************************************************
1776 * Forced closedown of call *
1777 *************************************************/
1779 /* This function is called from log.c when Exim is dying because of a serious
1780 disaster, and also from some other places. If an incoming non-batched SMTP
1781 channel is open, it swallows the rest of the incoming message if in the DATA
1782 phase, sends the reply string, and gives an error to all subsequent commands
1783 except QUIT. The existence of an SMTP call is detected by the non-NULLness of
1787 message SMTP reply string to send, excluding the code
1793 smtp_closedown(uschar * message)
1795 if (!smtp_in || smtp_batched_input) return;
1796 receive_swallow_smtp();
1797 smtp_printf("421 %s\r\n", FALSE, message);
1799 for (;;) switch(smtp_read_command(FALSE, GETC_BUFFER_UNLIMITED))
1805 f.smtp_in_quit = TRUE;
1806 smtp_printf("221 %s closing connection\r\n", FALSE, smtp_active_hostname);
1811 smtp_printf("250 Reset OK\r\n", FALSE);
1815 smtp_printf("421 %s\r\n", FALSE, message);
1823 /*************************************************
1824 * Set up connection info for logging *
1825 *************************************************/
1827 /* This function is called when logging information about an SMTP connection.
1828 It sets up appropriate source information, depending on the type of connection.
1829 If sender_fullhost is NULL, we are at a very early stage of the connection;
1830 just use the IP address.
1833 Returns: a string describing the connection
1837 smtp_get_connection_info(void)
1839 const uschar * hostname = sender_fullhost
1840 ? sender_fullhost : sender_host_address;
1843 return string_sprintf("SMTP connection from %s", hostname);
1845 if (f.sender_host_unknown || f.sender_host_notsocket)
1846 return string_sprintf("SMTP connection from %s", sender_ident);
1849 return string_sprintf("SMTP connection from %s (via inetd)", hostname);
1851 if (LOGGING(incoming_interface) && interface_address)
1852 return string_sprintf("SMTP connection from %s I=[%s]:%d", hostname,
1853 interface_address, interface_port);
1855 return string_sprintf("SMTP connection from %s", hostname);
1861 /* Append TLS-related information to a log line
1864 g String under construction: allocated string to extend, or NULL
1866 Returns: Allocated string or NULL
1869 s_tlslog(gstring * g)
1871 if (LOGGING(tls_cipher) && tls_in.cipher)
1873 g = string_append(g, 2, US" X=", tls_in.cipher);
1874 #ifndef DISABLE_TLS_RESUME
1875 if (LOGGING(tls_resumption) && tls_in.resumption & RESUME_USED)
1876 g = string_catn(g, US"*", 1);
1879 if (LOGGING(tls_certificate_verified) && tls_in.cipher)
1880 g = string_append(g, 2, US" CV=", tls_in.certificate_verified? "yes":"no");
1881 if (LOGGING(tls_peerdn) && tls_in.peerdn)
1882 g = string_append(g, 3, US" DN=\"", string_printing(tls_in.peerdn), US"\"");
1883 if (LOGGING(tls_sni) && tls_in.sni)
1884 g = string_append(g, 2, US" SNI=", string_printing2(tls_in.sni, SP_TAB|SP_SPACE));
1892 s_connhad_log(gstring * g)
1894 const uschar * sep = smtp_connection_had[SMTP_HBUFF_SIZE-1] != SCH_NONE
1895 ? US" C=..." : US" C=";
1897 for (int i = smtp_ch_index; i < SMTP_HBUFF_SIZE; i++)
1898 if (smtp_connection_had[i] != SCH_NONE)
1900 g = string_append(g, 2, sep, smtp_names[smtp_connection_had[i]]);
1903 for (int i = 0; i < smtp_ch_index; i++, sep = US",")
1904 g = string_append(g, 2, sep, smtp_names[smtp_connection_had[i]]);
1909 /*************************************************
1910 * Log lack of MAIL if so configured *
1911 *************************************************/
1913 /* This function is called when an SMTP session ends. If the log selector
1914 smtp_no_mail is set, write a log line giving some details of what has happened
1915 in the SMTP session.
1922 smtp_log_no_mail(void)
1927 if (smtp_mailcmd_count > 0 || !LOGGING(smtp_no_mail))
1930 if (sender_host_authenticated)
1932 g = string_append(g, 2, US" A=", sender_host_authenticated);
1933 if (authenticated_id) g = string_append(g, 2, US":", authenticated_id);
1940 g = s_connhad_log(g);
1942 if (!(s = string_from_gstring(g))) s = US"";
1944 log_write(0, LOG_MAIN, "no MAIL in %sSMTP connection from %s D=%s%s",
1945 f.tcp_in_fastopen ? f.tcp_in_fastopen_data ? US"TFO* " : US"TFO " : US"",
1946 host_and_ident(FALSE), string_timesince(&smtp_connection_start), s);
1950 /* Return list of recent smtp commands */
1955 gstring * list = NULL;
1958 for (int i = smtp_ch_index; i < SMTP_HBUFF_SIZE; i++)
1959 if (smtp_connection_had[i] != SCH_NONE)
1960 list = string_append_listele(list, ',', smtp_names[smtp_connection_had[i]]);
1962 for (int i = 0; i < smtp_ch_index; i++)
1963 list = string_append_listele(list, ',', smtp_names[smtp_connection_had[i]]);
1965 s = string_from_gstring(list);
1966 return s ? s : US"";
1972 /*************************************************
1973 * Check HELO line and set sender_helo_name *
1974 *************************************************/
1976 /* Check the format of a HELO line. The data for HELO/EHLO is supposed to be
1977 the domain name of the sending host, or an ip literal in square brackets. The
1978 argument is placed in sender_helo_name, which is in malloc store, because it
1979 must persist over multiple incoming messages. If helo_accept_junk is set, this
1980 host is permitted to send any old junk (needed for some broken hosts).
1981 Otherwise, helo_allow_chars can be used for rogue characters in general
1982 (typically people want to let in underscores).
1985 s the data portion of the line (already past any white space)
1987 Returns: TRUE or FALSE
1991 check_helo(uschar *s)
1994 uschar *end = s + Ustrlen(s);
1995 BOOL yield = fl.helo_accept_junk;
1997 /* Discard any previous helo name */
1999 sender_helo_name = NULL;
2001 /* Skip tests if junk is permitted. */
2005 /* Allow the new standard form for IPv6 address literals, namely,
2006 [IPv6:....], and because someone is bound to use it, allow an equivalent
2007 IPv4 form. Allow plain addresses as well. */
2014 if (strncmpic(s, US"[IPv6:", 6) == 0)
2015 yield = (string_is_ip_address(s+6, NULL) == 6);
2016 else if (strncmpic(s, US"[IPv4:", 6) == 0)
2017 yield = (string_is_ip_address(s+6, NULL) == 4);
2019 yield = (string_is_ip_address(s+1, NULL) != 0);
2024 /* Non-literals must be alpha, dot, hyphen, plus any non-valid chars
2025 that have been configured (usually underscore - sigh). */
2028 for (yield = TRUE; *s; s++)
2029 if (!isalnum(*s) && *s != '.' && *s != '-' &&
2030 Ustrchr(helo_allow_chars, *s) == NULL)
2036 /* Save argument if OK */
2038 if (yield) sender_helo_name = string_copy_perm(start, TRUE);
2046 /*************************************************
2047 * Extract SMTP command option *
2048 *************************************************/
2050 /* This function picks the next option setting off the end of smtp_cmd_data. It
2051 is called for MAIL FROM and RCPT TO commands, to pick off the optional ESMTP
2052 things that can appear there.
2055 name point this at the name
2056 value point this at the data string
2058 Returns: TRUE if found an option
2062 extract_option(uschar **name, uschar **value)
2066 if (Ustrlen(smtp_cmd_data) <= 0) return FALSE;
2067 v = smtp_cmd_data + Ustrlen(smtp_cmd_data) - 1;
2068 while (v > smtp_cmd_data && isspace(*v)) v--;
2071 while (v > smtp_cmd_data && *v != '=' && !isspace(*v))
2073 /* Take care to not stop at a space embedded in a quoted local-part */
2076 do v--; while (v > smtp_cmd_data && *v != '"');
2077 if (v <= smtp_cmd_data) return FALSE;
2081 if (v <= smtp_cmd_data) return FALSE;
2086 while (n > smtp_cmd_data && isalpha(n[-1])) n--;
2087 /* RFC says SP, but TAB seen in wild and other major MTAs accept it */
2088 if (n <= smtp_cmd_data || !isspace(n[-1])) return FALSE;
2105 /*************************************************
2106 * Reset for new message *
2107 *************************************************/
2109 /* This function is called whenever the SMTP session is reset from
2110 within either of the setup functions; also from the daemon loop.
2112 Argument: the stacking pool storage reset point
2117 smtp_reset(void *reset_point)
2119 recipients_list = NULL;
2120 rcpt_count = rcpt_defer_count = rcpt_fail_count =
2121 raw_recipients_count = recipients_count = recipients_list_max = 0;
2122 message_linecount = 0;
2124 message_body = message_body_end = NULL;
2125 acl_added_headers = NULL;
2126 acl_removed_headers = NULL;
2127 f.queue_only_policy = FALSE;
2128 rcpt_smtp_response = NULL;
2129 fl.rcpt_smtp_response_same = TRUE;
2130 fl.rcpt_in_progress = FALSE;
2131 f.deliver_freeze = FALSE; /* Can be set by ACL */
2132 freeze_tell = freeze_tell_config; /* Can be set by ACL */
2133 fake_response = OK; /* Can be set by ACL */
2134 #ifdef WITH_CONTENT_SCAN
2135 f.no_mbox_unspool = FALSE; /* Can be set by ACL */
2137 f.submission_mode = FALSE; /* Can be set by ACL */
2138 f.suppress_local_fixups = f.suppress_local_fixups_default; /* Can be set by ACL */
2139 f.active_local_from_check = local_from_check; /* Can be set by ACL */
2140 f.active_local_sender_retain = local_sender_retain; /* Can be set by ACL */
2141 sending_ip_address = NULL;
2142 return_path = sender_address = NULL;
2143 deliver_localpart_data = deliver_domain_data =
2144 recipient_data = sender_data = NULL; /* Can be set by ACL */
2145 recipient_verify_failure = NULL;
2146 deliver_localpart_parent = deliver_localpart_orig = NULL;
2147 deliver_domain_parent = deliver_domain_orig = NULL;
2148 callout_address = NULL;
2149 submission_name = NULL; /* Can be set by ACL */
2150 raw_sender = NULL; /* After SMTP rewrite, before qualifying */
2151 sender_address_unrewritten = NULL; /* Set only after verify rewrite */
2152 sender_verified_list = NULL; /* No senders verified */
2153 memset(sender_address_cache, 0, sizeof(sender_address_cache));
2154 memset(sender_domain_cache, 0, sizeof(sender_domain_cache));
2156 authenticated_sender = NULL;
2157 #ifdef EXPERIMENTAL_BRIGHTMAIL
2159 bmi_verdicts = NULL;
2161 dnslist_domain = dnslist_matched = NULL;
2163 spf_header_comment = spf_received = spf_result = spf_smtp_comment = NULL;
2164 spf_result_guessed = FALSE;
2166 #ifndef DISABLE_DKIM
2167 dkim_cur_signer = dkim_signers =
2168 dkim_signing_domain = dkim_signing_selector = dkim_signatures = NULL;
2169 dkim_cur_signer = dkim_signers = dkim_signing_domain = dkim_signing_selector = NULL;
2170 f.dkim_disable_verify = FALSE;
2171 dkim_collect_input = 0;
2172 dkim_verify_overall = dkim_verify_status = dkim_verify_reason = NULL;
2173 dkim_key_length = 0;
2175 #ifdef SUPPORT_DMARC
2176 f.dmarc_has_been_checked = f.dmarc_disable_verify = f.dmarc_enable_forensic = FALSE;
2177 dmarc_domain_policy = dmarc_status = dmarc_status_text =
2178 dmarc_used_domain = NULL;
2180 #ifdef EXPERIMENTAL_ARC
2181 arc_state = arc_state_reason = NULL;
2182 arc_received_instance = 0;
2186 deliver_host = deliver_host_address = NULL; /* Can be set by ACL */
2187 #ifndef DISABLE_PRDR
2188 prdr_requested = FALSE;
2191 message_smtputf8 = FALSE;
2193 #ifdef WITH_CONTENT_SCAN
2196 body_linecount = body_zerocount = 0;
2198 lookup_value = NULL; /* Can be set by ACL */
2199 sender_rate = sender_rate_limit = sender_rate_period = NULL;
2200 ratelimiters_mail = NULL; /* Updated by ratelimit ACL condition */
2201 /* Note that ratelimiters_conn persists across resets. */
2203 /* Reset message ACL variables */
2207 /* Warning log messages are saved in malloc store. They are saved to avoid
2208 repetition in the same message, but it seems right to repeat them for different
2211 while (acl_warn_logged)
2213 string_item *this = acl_warn_logged;
2214 acl_warn_logged = acl_warn_logged->next;
2219 store_reset(reset_point);
2222 return store_mark();
2229 /*************************************************
2230 * Initialize for incoming batched SMTP message *
2231 *************************************************/
2233 /* This function is called from smtp_setup_msg() in the case when
2234 smtp_batched_input is true. This happens when -bS is used to pass a whole batch
2235 of messages in one file with SMTP commands between them. All errors must be
2236 reported by sending a message, and only MAIL FROM, RCPT TO, and DATA are
2237 relevant. After an error on a sender, or an invalid recipient, the remainder
2238 of the message is skipped. The value of received_protocol is already set.
2241 Returns: > 0 message successfully started (reached DATA)
2242 = 0 QUIT read or end of file reached
2243 < 0 should not occur
2247 smtp_setup_batch_msg(void)
2250 rmark reset_point = store_mark();
2252 /* Save the line count at the start of each transaction - single commands
2253 like HELO and RSET count as whole transactions. */
2255 bsmtp_transaction_linecount = receive_linecount;
2257 if ((receive_feof)()) return 0; /* Treat EOF as QUIT */
2259 cancel_cutthrough_connection(TRUE, US"smtp_setup_batch_msg");
2260 reset_point = smtp_reset(reset_point); /* Reset for start of message */
2262 /* Deal with SMTP commands. This loop is exited by setting done to a POSITIVE
2263 value. The values are 2 larger than the required yield of the function. */
2268 uschar *recipient = NULL;
2269 int start, end, sender_domain, recipient_domain;
2271 switch(smtp_read_command(FALSE, GETC_BUFFER_UNLIMITED))
2273 /* The HELO/EHLO commands set sender_address_helo if they have
2274 valid data; otherwise they are ignored, except that they do
2275 a reset of the state. */
2280 check_helo(smtp_cmd_data);
2284 cancel_cutthrough_connection(TRUE, US"RSET received");
2285 reset_point = smtp_reset(reset_point);
2286 bsmtp_transaction_linecount = receive_linecount;
2290 /* The MAIL FROM command requires an address as an operand. All we
2291 do here is to parse it for syntactic correctness. The form "<>" is
2292 a special case which converts into an empty string. The start/end
2293 pointers in the original are not used further for this address, as
2294 it is the canonical extracted address which is all that is kept. */
2297 smtp_mailcmd_count++; /* Count for no-mail log */
2299 /* The function moan_smtp_batch() does not return. */
2300 moan_smtp_batch(smtp_cmd_buffer, "503 Sender already given");
2302 if (smtp_cmd_data[0] == 0)
2303 /* The function moan_smtp_batch() does not return. */
2304 moan_smtp_batch(smtp_cmd_buffer, "501 MAIL FROM must have an address operand");
2306 /* Reset to start of message */
2308 cancel_cutthrough_connection(TRUE, US"MAIL received");
2309 reset_point = smtp_reset(reset_point);
2311 /* Apply SMTP rewrite */
2313 raw_sender = rewrite_existflags & rewrite_smtp
2314 /* deconst ok as smtp_cmd_data was not const */
2315 ? US rewrite_one(smtp_cmd_data, rewrite_smtp|rewrite_smtp_sender, NULL,
2316 FALSE, US"", global_rewrite_rules)
2319 /* Extract the address; the TRUE flag allows <> as valid */
2322 parse_extract_address(raw_sender, &errmess, &start, &end, &sender_domain,
2326 /* The function moan_smtp_batch() does not return. */
2327 moan_smtp_batch(smtp_cmd_buffer, "501 %s", errmess);
2329 sender_address = string_copy(raw_sender);
2331 /* Qualify unqualified sender addresses if permitted to do so. */
2334 && sender_address[0] != 0 && sender_address[0] != '@')
2335 if (f.allow_unqualified_sender)
2337 /* deconst ok as sender_address was not const */
2338 sender_address = US rewrite_address_qualify(sender_address, FALSE);
2339 DEBUG(D_receive) debug_printf("unqualified address %s accepted "
2340 "and rewritten\n", raw_sender);
2342 /* The function moan_smtp_batch() does not return. */
2344 moan_smtp_batch(smtp_cmd_buffer, "501 sender address must contain "
2349 /* The RCPT TO command requires an address as an operand. All we do
2350 here is to parse it for syntactic correctness. There may be any number
2351 of RCPT TO commands, specifying multiple senders. We build them all into
2352 a data structure that is in argc/argv format. The start/end values
2353 given by parse_extract_address are not used, as we keep only the
2354 extracted address. */
2357 if (!sender_address)
2358 /* The function moan_smtp_batch() does not return. */
2359 moan_smtp_batch(smtp_cmd_buffer, "503 No sender yet given");
2361 if (smtp_cmd_data[0] == 0)
2362 /* The function moan_smtp_batch() does not return. */
2363 moan_smtp_batch(smtp_cmd_buffer,
2364 "501 RCPT TO must have an address operand");
2366 /* Check maximum number allowed */
2368 if (recipients_max > 0 && recipients_count + 1 > recipients_max)
2369 /* The function moan_smtp_batch() does not return. */
2370 moan_smtp_batch(smtp_cmd_buffer, "%s too many recipients",
2371 recipients_max_reject? "552": "452");
2373 /* Apply SMTP rewrite, then extract address. Don't allow "<>" as a
2374 recipient address */
2376 recipient = rewrite_existflags & rewrite_smtp
2377 /* deconst ok as smtp_cmd_data was not const */
2378 ? US rewrite_one(smtp_cmd_data, rewrite_smtp, NULL, FALSE, US"",
2379 global_rewrite_rules)
2382 recipient = parse_extract_address(recipient, &errmess, &start, &end,
2383 &recipient_domain, FALSE);
2386 /* The function moan_smtp_batch() does not return. */
2387 moan_smtp_batch(smtp_cmd_buffer, "501 %s", errmess);
2389 /* If the recipient address is unqualified, qualify it if permitted. Then
2390 add it to the list of recipients. */
2392 if (!recipient_domain)
2393 if (f.allow_unqualified_recipient)
2395 DEBUG(D_receive) debug_printf("unqualified address %s accepted\n",
2397 /* deconst ok as recipient was not const */
2398 recipient = US rewrite_address_qualify(recipient, TRUE);
2400 /* The function moan_smtp_batch() does not return. */
2402 moan_smtp_batch(smtp_cmd_buffer,
2403 "501 recipient address must contain a domain");
2405 receive_add_recipient(recipient, -1);
2409 /* The DATA command is legal only if it follows successful MAIL FROM
2410 and RCPT TO commands. This function is complete when a valid DATA
2411 command is encountered. */
2414 if (!sender_address || recipients_count <= 0)
2415 /* The function moan_smtp_batch() does not return. */
2416 if (!sender_address)
2417 moan_smtp_batch(smtp_cmd_buffer,
2418 "503 MAIL FROM:<sender> command must precede DATA");
2420 moan_smtp_batch(smtp_cmd_buffer,
2421 "503 RCPT TO:<recipient> must precede DATA");
2424 done = 3; /* DATA successfully achieved */
2425 message_ended = END_NOTENDED; /* Indicate in middle of message */
2430 /* The VRFY, EXPN, HELP, ETRN, and NOOP commands are ignored. */
2437 bsmtp_transaction_linecount = receive_linecount;
2442 f.smtp_in_quit = TRUE;
2449 /* The function moan_smtp_batch() does not return. */
2450 moan_smtp_batch(smtp_cmd_buffer, "501 Unexpected argument data");
2455 /* The function moan_smtp_batch() does not return. */
2456 moan_smtp_batch(smtp_cmd_buffer, "501 Unexpected NULL in SMTP command");
2461 /* The function moan_smtp_batch() does not return. */
2462 moan_smtp_batch(smtp_cmd_buffer, "500 Command unrecognized");
2467 return done - 2; /* Convert yield values */
2475 smtp_log_tls_fail(const uschar * errstr)
2477 const uschar * conn_info = smtp_get_connection_info();
2479 if (Ustrncmp(conn_info, US"SMTP ", 5) == 0) conn_info += 5;
2480 /* I'd like to get separated H= here, but too hard for now */
2482 log_write(0, LOG_MAIN, "TLS error on %s %s", conn_info, errstr);
2496 socklen_t len = sizeof(is_fastopen);
2498 /* The tinfo TCPOPT_FAST_OPEN bit seems unreliable, and we don't see state
2499 TCP_SYN_RCV (as of 12.1) so no idea about data-use. */
2501 if (getsockopt(fileno(smtp_out), IPPROTO_TCP, TCP_FASTOPEN, &is_fastopen, &len) == 0)
2506 debug_printf("TFO mode connection (TCP_FASTOPEN getsockopt)\n");
2507 f.tcp_in_fastopen = TRUE;
2510 else DEBUG(D_receive)
2511 debug_printf("TCP_INFO getsockopt: %s\n", strerror(errno));
2513 # elif defined(TCP_INFO)
2514 struct tcp_info tinfo;
2515 socklen_t len = sizeof(tinfo);
2517 if (getsockopt(fileno(smtp_out), IPPROTO_TCP, TCP_INFO, &tinfo, &len) == 0)
2518 # ifdef TCPI_OPT_SYN_DATA /* FreeBSD 11,12 do not seem to have this yet */
2519 if (tinfo.tcpi_options & TCPI_OPT_SYN_DATA)
2522 debug_printf("TFO mode connection (ACKd data-on-SYN)\n");
2523 f.tcp_in_fastopen_data = f.tcp_in_fastopen = TRUE;
2527 if (tinfo.tcpi_state == TCP_SYN_RECV) /* Not seen on FreeBSD 12.1 */
2530 debug_printf("TFO mode connection (state TCP_SYN_RECV)\n");
2531 f.tcp_in_fastopen = TRUE;
2533 else DEBUG(D_receive)
2534 debug_printf("TCP_INFO getsockopt: %s\n", strerror(errno));
2541 log_connect_tls_drop(const uschar * what, const uschar * log_msg)
2543 gstring * g = s_tlslog(NULL);
2544 uschar * tls = string_from_gstring(g);
2546 log_write(L_connection_reject,
2547 log_reject_target, "%s%s%s dropped by %s%s%s",
2548 LOGGING(dnssec) && sender_host_dnssec ? US" DS" : US"",
2549 host_and_ident(TRUE),
2552 log_msg ? US": " : US"", log_msg);
2556 /*************************************************
2557 * Start an SMTP session *
2558 *************************************************/
2560 /* This function is called at the start of an SMTP session. Thereafter,
2561 smtp_setup_msg() is called to initiate each separate message. This
2562 function does host-specific testing, and outputs the banner line.
2565 Returns: FALSE if the session can not continue; something has
2566 gone wrong, or the connection to the host is blocked
2570 smtp_start_session(void)
2573 uschar *user_msg, *log_msg;
2578 gettimeofday(&smtp_connection_start, NULL);
2579 for (smtp_ch_index = 0; smtp_ch_index < SMTP_HBUFF_SIZE; smtp_ch_index++)
2580 smtp_connection_had[smtp_ch_index] = SCH_NONE;
2583 /* Default values for certain variables */
2585 fl.helo_seen = fl.esmtp = fl.helo_accept_junk = FALSE;
2586 smtp_mailcmd_count = 0;
2587 count_nonmail = TRUE_UNSET;
2588 synprot_error_count = unknown_command_count = nonmail_command_count = 0;
2589 smtp_delay_mail = smtp_rlm_base;
2590 fl.auth_advertised = FALSE;
2591 f.smtp_in_pipelining_advertised = f.smtp_in_pipelining_used = FALSE;
2592 f.pipelining_enable = TRUE;
2593 sync_cmd_limit = NON_SYNC_CMD_NON_PIPELINING;
2594 fl.smtp_exit_function_called = FALSE; /* For avoiding loop in not-quit exit */
2596 /* If receiving by -bs from a trusted user, or testing with -bh, we allow
2597 authentication settings from -oMaa to remain in force. */
2599 if (!host_checking && !f.sender_host_notsocket)
2600 sender_host_auth_pubname = sender_host_authenticated = NULL;
2601 authenticated_by = NULL;
2604 tls_in.ver = tls_in.cipher = tls_in.peerdn = NULL;
2605 tls_in.ourcert = tls_in.peercert = NULL;
2607 tls_in.ocsp = OCSP_NOT_REQ;
2608 fl.tls_advertised = FALSE;
2610 fl.dsn_advertised = FALSE;
2612 fl.smtputf8_advertised = FALSE;
2615 /* Reset ACL connection variables */
2619 /* Allow for trailing 0 in the command and data buffers. Tainted. */
2621 smtp_cmd_buffer = store_get_perm(2*SMTP_CMD_BUFFER_SIZE + 2, GET_TAINTED);
2623 smtp_cmd_buffer[0] = 0;
2624 smtp_data_buffer = smtp_cmd_buffer + SMTP_CMD_BUFFER_SIZE + 1;
2626 /* For batched input, the protocol setting can be overridden from the
2627 command line by a trusted caller. */
2629 if (smtp_batched_input)
2631 if (!received_protocol) received_protocol = US"local-bsmtp";
2634 /* For non-batched SMTP input, the protocol setting is forced here. It will be
2635 reset later if any of EHLO/AUTH/STARTTLS are received. */
2639 (sender_host_address ? protocols : protocols_local) [pnormal];
2641 /* Set up the buffer for inputting using direct read() calls, and arrange to
2642 call the local functions instead of the standard C ones. */
2646 receive_getc = smtp_getc;
2647 receive_getbuf = smtp_getbuf;
2648 receive_get_cache = smtp_get_cache;
2649 receive_hasc = smtp_hasc;
2650 receive_ungetc = smtp_ungetc;
2651 receive_feof = smtp_feof;
2652 receive_ferror = smtp_ferror;
2653 lwr_receive_getc = NULL;
2654 lwr_receive_getbuf = NULL;
2655 lwr_receive_hasc = NULL;
2656 lwr_receive_ungetc = NULL;
2658 /* Set up the message size limit; this may be host-specific */
2660 thismessage_size_limit = expand_string_integer(message_size_limit, TRUE);
2661 if (expand_string_message)
2663 if (thismessage_size_limit == -1)
2664 log_write(0, LOG_MAIN|LOG_PANIC, "unable to expand message_size_limit: "
2665 "%s", expand_string_message);
2667 log_write(0, LOG_MAIN|LOG_PANIC, "invalid message_size_limit: "
2668 "%s", expand_string_message);
2669 smtp_closedown(US"Temporary local problem - please try later");
2673 /* When a message is input locally via the -bs or -bS options, sender_host_
2674 unknown is set unless -oMa was used to force an IP address, in which case it
2675 is checked like a real remote connection. When -bs is used from inetd, this
2676 flag is not set, causing the sending host to be checked. The code that deals
2677 with IP source routing (if configured) is never required for -bs or -bS and
2678 the flag sender_host_notsocket is used to suppress it.
2680 If smtp_accept_max and smtp_accept_reserve are set, keep some connections in
2681 reserve for certain hosts and/or networks. */
2683 if (!f.sender_host_unknown)
2686 BOOL reserved_host = FALSE;
2688 /* Look up IP options (source routing info) on the socket if this is not an
2689 -oMa "host", and if any are found, log them and drop the connection.
2691 Linux (and others now, see below) is different to everyone else, so there
2692 has to be some conditional compilation here. Versions of Linux before 2.1.15
2693 used a structure whose name was "options". Somebody finally realized that
2694 this name was silly, and it got changed to "ip_options". I use the
2695 newer name here, but there is a fudge in the script that sets up os.h
2696 to define a macro in older Linux systems.
2698 Sigh. Linux is a fast-moving target. Another generation of Linux uses
2699 glibc 2, which has chosen ip_opts for the structure name. This is now
2700 really a glibc thing rather than a Linux thing, so the condition name
2701 has been changed to reflect this. It is relevant also to GNU/Hurd.
2703 Mac OS 10.x (Darwin) is like the later glibc versions, but without the
2704 setting of the __GLIBC__ macro, so we can't detect it automatically. There's
2705 a special macro defined in the os.h file.
2707 Some DGUX versions on older hardware appear not to support IP options at
2708 all, so there is now a general macro which can be set to cut out this
2711 How to do this properly in IPv6 is not yet known. */
2713 #if !HAVE_IPV6 && !defined(NO_IP_OPTIONS)
2715 # ifdef GLIBC_IP_OPTIONS
2716 # if (!defined __GLIBC__) || (__GLIBC__ < 2)
2721 # elif defined DARWIN_IP_OPTIONS
2727 if (!host_checking && !f.sender_host_notsocket)
2730 EXIM_SOCKLEN_T optlen = sizeof(struct ip_options) + MAX_IPOPTLEN;
2731 struct ip_options *ipopt = store_get(optlen, GET_UNTAINTED);
2732 # elif OPTSTYLE == 2
2733 struct ip_opts ipoptblock;
2734 struct ip_opts *ipopt = &ipoptblock;
2735 EXIM_SOCKLEN_T optlen = sizeof(ipoptblock);
2737 struct ipoption ipoptblock;
2738 struct ipoption *ipopt = &ipoptblock;
2739 EXIM_SOCKLEN_T optlen = sizeof(ipoptblock);
2742 /* Occasional genuine failures of getsockopt() have been seen - for
2743 example, "reset by peer". Therefore, just log and give up on this
2744 call, unless the error is ENOPROTOOPT. This error is given by systems
2745 that have the interfaces but not the mechanism - e.g. GNU/Hurd at the time
2746 of writing. So for that error, carry on - we just can't do an IP options
2749 DEBUG(D_receive) debug_printf("checking for IP options\n");
2751 if (getsockopt(fileno(smtp_out), IPPROTO_IP, IP_OPTIONS, US (ipopt),
2754 if (errno != ENOPROTOOPT)
2756 log_write(0, LOG_MAIN, "getsockopt() failed from %s: %s",
2757 host_and_ident(FALSE), strerror(errno));
2758 smtp_printf("451 SMTP service not available\r\n", FALSE);
2763 /* Deal with any IP options that are set. On the systems I have looked at,
2764 the value of MAX_IPOPTLEN has been 40, meaning that there should never be
2765 more logging data than will fit in big_buffer. Nevertheless, after somebody
2766 questioned this code, I've added in some paranoid checking. */
2768 else if (optlen > 0)
2770 uschar * p = big_buffer;
2771 uschar * pend = big_buffer + big_buffer_size;
2774 struct in_addr addr;
2777 uschar * optstart = US (ipopt->__data);
2778 # elif OPTSTYLE == 2
2779 uschar * optstart = US (ipopt->ip_opts);
2781 uschar * optstart = US (ipopt->ipopt_list);
2784 DEBUG(D_receive) debug_printf("IP options exist\n");
2786 Ustrcpy(p, "IP options on incoming call:");
2789 for (uschar * opt = optstart; opt && opt < US (ipopt) + optlen; )
2804 string_format(p, pend-p, " %s [@%s",
2805 (*opt == IPOPT_SSRR)? "SSRR" : "LSRR",
2806 inet_ntoa(*((struct in_addr *)(&(ipopt->faddr)))))
2807 # elif OPTSTYLE == 2
2808 string_format(p, pend-p, " %s [@%s",
2809 (*opt == IPOPT_SSRR)? "SSRR" : "LSRR",
2810 inet_ntoa(ipopt->ip_dst))
2812 string_format(p, pend-p, " %s [@%s",
2813 (*opt == IPOPT_SSRR)? "SSRR" : "LSRR",
2814 inet_ntoa(ipopt->ipopt_dst))
2823 optcount = (opt[1] - 3) / sizeof(struct in_addr);
2825 while (optcount-- > 0)
2827 memcpy(&addr, adptr, sizeof(addr));
2828 if (!string_format(p, pend - p - 1, "%s%s",
2829 (optcount == 0)? ":" : "@", inet_ntoa(addr)))
2835 adptr += sizeof(struct in_addr);
2843 if (pend - p < 4 + 3*opt[1]) { opt = NULL; break; }
2846 for (int i = 0; i < opt[1]; i++)
2847 p += sprintf(CS p, "%2.2x ", opt[i]);
2855 log_write(0, LOG_MAIN, "%s", big_buffer);
2857 /* Refuse any call with IP options. This is what tcpwrappers 7.5 does. */
2859 log_write(0, LOG_MAIN|LOG_REJECT,
2860 "connection from %s refused (IP options)", host_and_ident(FALSE));
2862 smtp_printf("554 SMTP service not available\r\n", FALSE);
2866 /* Length of options = 0 => there are no options */
2868 else DEBUG(D_receive) debug_printf("no IP options found\n");
2870 #endif /* HAVE_IPV6 && !defined(NO_IP_OPTIONS) */
2872 /* Set keep-alive in socket options. The option is on by default. This
2873 setting is an attempt to get rid of some hanging connections that stick in
2874 read() when the remote end (usually a dialup) goes away. */
2876 if (smtp_accept_keepalive && !f.sender_host_notsocket)
2877 ip_keepalive(fileno(smtp_out), sender_host_address, FALSE);
2879 /* If the current host matches host_lookup, set the name by doing a
2880 reverse lookup. On failure, sender_host_name will be NULL and
2881 host_lookup_failed will be TRUE. This may or may not be serious - optional
2884 if (verify_check_host(&host_lookup) == OK)
2886 (void)host_name_lookup();
2887 host_build_sender_fullhost();
2890 /* Delay this until we have the full name, if it is looked up. */
2892 set_process_info("handling incoming connection from %s",
2893 host_and_ident(FALSE));
2895 /* Expand smtp_receive_timeout, if needed */
2897 if (smtp_receive_timeout_s)
2900 if ( !(exp = expand_string(smtp_receive_timeout_s))
2902 || (smtp_receive_timeout = readconf_readtime(exp, 0, FALSE)) < 0
2904 log_write(0, LOG_MAIN|LOG_PANIC,
2905 "bad value for smtp_receive_timeout: '%s'", exp ? exp : US"");
2908 /* Test for explicit connection rejection */
2910 if (verify_check_host(&host_reject_connection) == OK)
2912 log_write(L_connection_reject, LOG_MAIN|LOG_REJECT, "refused connection "
2913 "from %s (host_reject_connection)", host_and_ident(FALSE));
2915 if (!tls_in.on_connect)
2917 smtp_printf("554 SMTP service not available\r\n", FALSE);
2921 /* Test with TCP Wrappers if so configured. There is a problem in that
2922 hosts_ctl() returns 0 (deny) under a number of system failure circumstances,
2923 such as disks dying. In these cases, it is desirable to reject with a 4xx
2924 error instead of a 5xx error. There isn't a "right" way to detect such
2925 problems. The following kludge is used: errno is zeroed before calling
2926 hosts_ctl(). If the result is "reject", a 5xx error is given only if the
2927 value of errno is 0 or ENOENT (which happens if /etc/hosts.{allow,deny} does
2930 #ifdef USE_TCP_WRAPPERS
2932 if (!(tcp_wrappers_name = expand_string(tcp_wrappers_daemon_name)))
2933 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "Expansion of \"%s\" "
2934 "(tcp_wrappers_name) failed: %s", string_printing(tcp_wrappers_name),
2935 expand_string_message);
2937 if (!hosts_ctl(tcp_wrappers_name,
2938 sender_host_name ? CS sender_host_name : STRING_UNKNOWN,
2939 sender_host_address ? CS sender_host_address : STRING_UNKNOWN,
2940 sender_ident ? CS sender_ident : STRING_UNKNOWN))
2942 if (errno == 0 || errno == ENOENT)
2944 HDEBUG(D_receive) debug_printf("tcp wrappers rejection\n");
2945 log_write(L_connection_reject,
2946 LOG_MAIN|LOG_REJECT, "refused connection from %s "
2947 "(tcp wrappers)", host_and_ident(FALSE));
2948 smtp_printf("554 SMTP service not available\r\n", FALSE);
2952 int save_errno = errno;
2953 HDEBUG(D_receive) debug_printf("tcp wrappers rejected with unexpected "
2954 "errno value %d\n", save_errno);
2955 log_write(L_connection_reject,
2956 LOG_MAIN|LOG_REJECT, "temporarily refused connection from %s "
2957 "(tcp wrappers errno=%d)", host_and_ident(FALSE), save_errno);
2958 smtp_printf("451 Temporary local problem - please try later\r\n", FALSE);
2964 /* Check for reserved slots. The value of smtp_accept_count has already been
2965 incremented to include this process. */
2967 if (smtp_accept_max > 0 &&
2968 smtp_accept_count > smtp_accept_max - smtp_accept_reserve)
2970 if ((rc = verify_check_host(&smtp_reserve_hosts)) != OK)
2972 log_write(L_connection_reject,
2973 LOG_MAIN, "temporarily refused connection from %s: not in "
2974 "reserve list: connected=%d max=%d reserve=%d%s",
2975 host_and_ident(FALSE), smtp_accept_count - 1, smtp_accept_max,
2976 smtp_accept_reserve, (rc == DEFER)? " (lookup deferred)" : "");
2977 smtp_printf("421 %s: Too many concurrent SMTP connections; "
2978 "please try again later\r\n", FALSE, smtp_active_hostname);
2981 reserved_host = TRUE;
2984 /* If a load level above which only messages from reserved hosts are
2985 accepted is set, check the load. For incoming calls via the daemon, the
2986 check is done in the superior process if there are no reserved hosts, to
2987 save a fork. In all cases, the load average will already be available
2988 in a global variable at this point. */
2990 if (smtp_load_reserve >= 0 &&
2991 load_average > smtp_load_reserve &&
2993 verify_check_host(&smtp_reserve_hosts) != OK)
2995 log_write(L_connection_reject,
2996 LOG_MAIN, "temporarily refused connection from %s: not in "
2997 "reserve list and load average = %.2f", host_and_ident(FALSE),
2998 (double)load_average/1000.0);
2999 smtp_printf("421 %s: Too much load; please try again later\r\n", FALSE,
3000 smtp_active_hostname);
3004 /* Determine whether unqualified senders or recipients are permitted
3005 for this host. Unfortunately, we have to do this every time, in order to
3006 set the flags so that they can be inspected when considering qualifying
3007 addresses in the headers. For a site that permits no qualification, this
3008 won't take long, however. */
3010 f.allow_unqualified_sender =
3011 verify_check_host(&sender_unqualified_hosts) == OK;
3013 f.allow_unqualified_recipient =
3014 verify_check_host(&recipient_unqualified_hosts) == OK;
3016 /* Determine whether HELO/EHLO is required for this host. The requirement
3017 can be hard or soft. */
3019 fl.helo_verify_required = verify_check_host(&helo_verify_hosts) == OK;
3020 if (!fl.helo_verify_required)
3021 fl.helo_verify = verify_check_host(&helo_try_verify_hosts) == OK;
3023 /* Determine whether this hosts is permitted to send syntactic junk
3024 after a HELO or EHLO command. */
3026 fl.helo_accept_junk = verify_check_host(&helo_accept_junk_hosts) == OK;
3029 /* For batch SMTP input we are now done. */
3031 if (smtp_batched_input) return TRUE;
3033 /* If valid Proxy Protocol source is connecting, set up session.
3034 Failure will not allow any SMTP function other than QUIT. */
3036 #ifdef SUPPORT_PROXY
3037 proxy_session = FALSE;
3038 f.proxy_session_failed = FALSE;
3039 if (check_proxy_protocol_host())
3040 setup_proxy_protocol_host();
3043 /* Run the connect ACL if it exists */
3046 if (acl_smtp_connect)
3049 if ((rc = acl_check(ACL_WHERE_CONNECT, NULL, acl_smtp_connect, &user_msg,
3053 if (tls_in.on_connect)
3054 log_connect_tls_drop(US"'connect' ACL", log_msg);
3057 (void) smtp_handle_acl_fail(ACL_WHERE_CONNECT, rc, user_msg, log_msg);
3062 /* Start up TLS if tls_on_connect is set. This is for supporting the legacy
3063 smtps port for use with older style SSL MTAs. */
3066 if (tls_in.on_connect)
3068 if (tls_server_start(&user_msg) != OK)
3069 return smtp_log_tls_fail(user_msg);
3070 cmd_list[CL_TLAU].is_mail_cmd = TRUE;
3074 /* Output the initial message for a two-way SMTP connection. It may contain
3075 newlines, which then cause a multi-line response to be given. */
3077 code = US"220"; /* Default status code */
3078 esc = US""; /* Default extended status code */
3079 esclen = 0; /* Length of esc */
3085 smtp_message_code(&code, &codelen, &s, NULL, TRUE);
3089 esclen = codelen - 4;
3092 else if (!(s = expand_string(smtp_banner)))
3094 log_write(0, f.expand_string_forcedfail ? LOG_MAIN : LOG_MAIN|LOG_PANIC_DIE,
3095 "Expansion of \"%s\" (smtp_banner) failed: %s",
3096 smtp_banner, expand_string_message);
3097 /* for force-fail */
3099 if (tls_in.on_connect) tls_close(NULL, TLS_SHUTDOWN_WAIT);
3104 /* Remove any terminating newlines; might as well remove trailing space too */
3107 while (p > s && isspace(p[-1])) p--;
3108 s = string_copyn(s, p-s);
3110 /* It seems that CC:Mail is braindead, and assumes that the greeting message
3111 is all contained in a single IP packet. The original code wrote out the
3112 greeting using several calls to fprint/fputc, and on busy servers this could
3113 cause it to be split over more than one packet - which caused CC:Mail to fall
3114 over when it got the second part of the greeting after sending its first
3115 command. Sigh. To try to avoid this, build the complete greeting message
3116 first, and output it in one fell swoop. This gives a better chance of it
3117 ending up as a single packet. */
3119 ss = string_get(256);
3122 do /* At least once, in case we have an empty string */
3125 uschar *linebreak = Ustrchr(p, '\n');
3126 ss = string_catn(ss, code, 3);
3130 ss = string_catn(ss, US" ", 1);
3134 len = linebreak - p;
3135 ss = string_catn(ss, US"-", 1);
3137 ss = string_catn(ss, esc, esclen);
3138 ss = string_catn(ss, p, len);
3139 ss = string_catn(ss, US"\r\n", 2);
3145 /* Before we write the banner, check that there is no input pending, unless
3146 this synchronisation check is disabled. */
3148 #ifndef DISABLE_PIPE_CONNECT
3149 fl.pipe_connect_acceptable =
3150 sender_host_address && verify_check_host(&pipe_connect_advertise_hosts) == OK;
3153 if (fl.pipe_connect_acceptable)
3154 f.smtp_in_early_pipe_used = TRUE;
3160 unsigned n = smtp_inend - smtp_inptr;
3161 if (n > 128) n = 128;
3163 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP protocol "
3164 "synchronization error (input sent without waiting for greeting): "
3165 "rejected connection from %s input=\"%s\"", host_and_ident(TRUE),
3166 string_printing(string_copyn(smtp_inptr, n)));
3167 smtp_printf("554 SMTP synchronization error\r\n", FALSE);
3171 /* Now output the banner */
3172 /*XXX the ehlo-resp code does its own tls/nontls bit. Maybe subroutine that? */
3175 #ifndef DISABLE_PIPE_CONNECT
3176 fl.pipe_connect_acceptable && pipeline_connect_sends(),
3180 string_from_gstring(ss));
3182 /* Attempt to see if we sent the banner before the last ACK of the 3-way
3183 handshake arrived. If so we must have managed a TFO. */
3186 if (sender_host_address && !f.sender_host_notsocket) tfo_in_check();
3196 /*************************************************
3197 * Handle SMTP syntax and protocol errors *
3198 *************************************************/
3200 /* Write to the log for SMTP syntax errors in incoming commands, if configured
3201 to do so. Then transmit the error response. The return value depends on the
3202 number of syntax and protocol errors in this SMTP session.
3205 type error type, given as a log flag bit
3206 code response code; <= 0 means don't send a response
3207 data data to reflect in the response (can be NULL)
3208 errmess the error message
3210 Returns: -1 limit of syntax/protocol errors NOT exceeded
3211 +1 limit of syntax/protocol errors IS exceeded
3213 These values fit in with the values of the "done" variable in the main
3214 processing loop in smtp_setup_msg(). */
3217 synprot_error(int type, int code, uschar *data, uschar *errmess)
3221 log_write(type, LOG_MAIN, "SMTP %s error in \"%s\" %s %s",
3222 type == L_smtp_syntax_error ? "syntax" : "protocol",
3223 string_printing(smtp_cmd_buffer), host_and_ident(TRUE), errmess);
3225 if (++synprot_error_count > smtp_max_synprot_errors)
3228 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
3229 "syntax or protocol errors (last command was \"%s\", %s)",
3230 host_and_ident(FALSE), string_printing(smtp_cmd_buffer),
3231 string_from_gstring(s_connhad_log(NULL))
3237 smtp_printf("%d%c%s%s%s\r\n", FALSE, code, yield == 1 ? '-' : ' ',
3238 data ? data : US"", data ? US": " : US"", errmess);
3240 smtp_printf("%d Too many syntax or protocol errors\r\n", FALSE, code);
3249 /*************************************************
3250 * Send SMTP response, possibly multiline *
3251 *************************************************/
3253 /* There are, it seems, broken clients out there that cannot handle multiline
3254 responses. If no_multiline_responses is TRUE (it can be set from an ACL), we
3255 output nothing for non-final calls, and only the first line for anything else.
3258 code SMTP code, may involve extended status codes
3259 codelen length of smtp code; if > 4 there's an ESC
3260 final FALSE if the last line isn't the final line
3261 msg message text, possibly containing newlines
3267 smtp_respond(uschar* code, int codelen, BOOL final, uschar *msg)
3272 if (!final && f.no_multiline_responses) return;
3277 esclen = codelen - 4;
3280 /* If this is the first output for a (non-batch) RCPT command, see if all RCPTs
3281 have had the same. Note: this code is also present in smtp_printf(). It would
3282 be tidier to have it only in one place, but when it was added, it was easier to
3283 do it that way, so as not to have to mess with the code for the RCPT command,
3284 which sometimes uses smtp_printf() and sometimes smtp_respond(). */
3286 if (fl.rcpt_in_progress)
3288 if (!rcpt_smtp_response)
3289 rcpt_smtp_response = string_copy(msg);
3290 else if (fl.rcpt_smtp_response_same &&
3291 Ustrcmp(rcpt_smtp_response, msg) != 0)
3292 fl.rcpt_smtp_response_same = FALSE;
3293 fl.rcpt_in_progress = FALSE;
3296 /* Now output the message, splitting it up into multiple lines if necessary.
3297 We only handle pipelining these responses as far as nonfinal/final groups,
3298 not the whole MAIL/RCPT/DATA response set. */
3302 uschar *nl = Ustrchr(msg, '\n');
3305 smtp_printf("%.3s%c%.*s%s\r\n", !final, code, final ? ' ':'-', esclen, esc, msg);
3308 else if (nl[1] == 0 || f.no_multiline_responses)
3310 smtp_printf("%.3s%c%.*s%.*s\r\n", !final, code, final ? ' ':'-', esclen, esc,
3311 (int)(nl - msg), msg);
3316 smtp_printf("%.3s-%.*s%.*s\r\n", TRUE, code, esclen, esc, (int)(nl - msg), msg);
3318 Uskip_whitespace(&msg);
3326 /*************************************************
3327 * Parse user SMTP message *
3328 *************************************************/
3330 /* This function allows for user messages overriding the response code details
3331 by providing a suitable response code string at the start of the message
3332 user_msg. Check the message for starting with a response code and optionally an
3333 extended status code. If found, check that the first digit is valid, and if so,
3334 change the code pointer and length to use the replacement. An invalid code
3335 causes a panic log; in this case, if the log messages is the same as the user
3336 message, we must also adjust the value of the log message to show the code that
3337 is actually going to be used (the original one).
3339 This function is global because it is called from receive.c as well as within
3342 Note that the code length returned includes the terminating whitespace
3343 character, which is always included in the regex match.
3346 code SMTP code, may involve extended status codes
3347 codelen length of smtp code; if > 4 there's an ESC
3349 log_msg optional log message, to be adjusted with the new SMTP code
3350 check_valid if true, verify the response code
3356 smtp_message_code(uschar **code, int *codelen, uschar **msg, uschar **log_msg,
3362 if (!msg || !*msg || !regex_match(regex_smtp_code, *msg, -1, &match))
3365 len = Ustrlen(match);
3366 if (check_valid && (*msg)[0] != (*code)[0])
3368 log_write(0, LOG_MAIN|LOG_PANIC, "configured error code starts with "
3369 "incorrect digit (expected %c) in \"%s\"", (*code)[0], *msg);
3370 if (log_msg && *log_msg == *msg)
3371 *log_msg = string_sprintf("%s %s", *code, *log_msg + len);
3376 *codelen = len; /* Includes final space */
3378 *msg += len; /* Chop the code off the message */
3385 /*************************************************
3386 * Handle an ACL failure *
3387 *************************************************/
3389 /* This function is called when acl_check() fails. As well as calls from within
3390 this module, it is called from receive.c for an ACL after DATA. It sorts out
3391 logging the incident, and sends the error response. A message containing
3392 newlines is turned into a multiline SMTP response, but for logging, only the
3395 There's a table of default permanent failure response codes to use in
3396 globals.c, along with the table of names. VFRY is special. Despite RFC1123 it
3397 defaults disabled in Exim. However, discussion in connection with RFC 821bis
3398 (aka RFC 2821) has concluded that the response should be 252 in the disabled
3399 state, because there are broken clients that try VRFY before RCPT. A 5xx
3400 response should be given only when the address is positively known to be
3401 undeliverable. Sigh. We return 252 if there is no VRFY ACL or it provides
3402 no explicit code, but if there is one we let it know best.
3403 Also, for ETRN, 458 is given on refusal, and for AUTH, 503.
3405 From Exim 4.63, it is possible to override the response code details by
3406 providing a suitable response code string at the start of the message provided
3407 in user_msg. The code's first digit is checked for validity.
3410 where where the ACL was called from
3412 user_msg a message that can be included in an SMTP response
3413 log_msg a message for logging
3415 Returns: 0 in most cases
3416 2 if the failure code was FAIL_DROP, in which case the
3417 SMTP connection should be dropped (this value fits with the
3418 "done" variable in smtp_setup_msg() below)
3422 smtp_handle_acl_fail(int where, int rc, uschar *user_msg, uschar *log_msg)
3424 BOOL drop = rc == FAIL_DROP;
3428 uschar *sender_info = US"";
3431 if (drop) rc = FAIL;
3433 /* Set the default SMTP code, and allow a user message to change it. */
3435 smtp_code = rc == FAIL ? acl_wherecodes[where] : US"451";
3436 smtp_message_code(&smtp_code, &codelen, &user_msg, &log_msg,
3437 where != ACL_WHERE_VRFY);
3439 /* We used to have sender_address here; however, there was a bug that was not
3440 updating sender_address after a rewrite during a verify. When this bug was
3441 fixed, sender_address at this point became the rewritten address. I'm not sure
3442 this is what should be logged, so I've changed to logging the unrewritten
3443 address to retain backward compatibility. */
3447 #ifdef WITH_CONTENT_SCAN
3448 case ACL_WHERE_MIME: what = US"during MIME ACL checks"; break;
3450 case ACL_WHERE_PREDATA: what = US"DATA"; break;
3451 case ACL_WHERE_DATA: what = US"after DATA"; break;
3452 #ifndef DISABLE_PRDR
3453 case ACL_WHERE_PRDR: what = US"after DATA PRDR"; break;
3457 uschar * place = smtp_cmd_data ? smtp_cmd_data : US"in \"connect\" ACL";
3460 if (where == ACL_WHERE_AUTH) /* avoid logging auth creds */
3463 for (s = smtp_cmd_data; *s && !isspace(*s); ) s++;
3464 lim = s - smtp_cmd_data; /* atop after method */
3466 what = string_sprintf("%s %.*s", acl_wherenames[where], lim, place);
3471 case ACL_WHERE_RCPT:
3472 case ACL_WHERE_DATA:
3473 #ifdef WITH_CONTENT_SCAN
3474 case ACL_WHERE_MIME:
3476 sender_info = string_sprintf("F=<%s>%s%s%s%s ",
3477 sender_address_unrewritten ? sender_address_unrewritten : sender_address,
3478 sender_host_authenticated ? US" A=" : US"",
3479 sender_host_authenticated ? sender_host_authenticated : US"",
3480 sender_host_authenticated && authenticated_id ? US":" : US"",
3481 sender_host_authenticated && authenticated_id ? authenticated_id : US""
3486 /* If there's been a sender verification failure with a specific message, and
3487 we have not sent a response about it yet, do so now, as a preliminary line for
3488 failures, but not defers. However, always log it for defer, and log it for fail
3489 unless the sender_verify_fail log selector has been turned off. */
3491 if (sender_verified_failed &&
3492 !testflag(sender_verified_failed, af_sverify_told))
3494 BOOL save_rcpt_in_progress = fl.rcpt_in_progress;
3495 fl.rcpt_in_progress = FALSE; /* So as not to treat these as the error */
3497 setflag(sender_verified_failed, af_sverify_told);
3499 if (rc != FAIL || LOGGING(sender_verify_fail))
3500 log_write(0, LOG_MAIN|LOG_REJECT, "%s sender verify %s for <%s>%s",
3501 host_and_ident(TRUE),
3502 ((sender_verified_failed->special_action & 255) == DEFER)? "defer":"fail",
3503 sender_verified_failed->address,
3504 (sender_verified_failed->message == NULL)? US"" :
3505 string_sprintf(": %s", sender_verified_failed->message));
3507 if (rc == FAIL && sender_verified_failed->user_message)
3508 smtp_respond(smtp_code, codelen, FALSE, string_sprintf(
3509 testflag(sender_verified_failed, af_verify_pmfail)?
3510 "Postmaster verification failed while checking <%s>\n%s\n"
3511 "Several RFCs state that you are required to have a postmaster\n"
3512 "mailbox for each mail domain. This host does not accept mail\n"
3513 "from domains whose servers reject the postmaster address."
3515 testflag(sender_verified_failed, af_verify_nsfail)?
3516 "Callback setup failed while verifying <%s>\n%s\n"
3517 "The initial connection, or a HELO or MAIL FROM:<> command was\n"
3518 "rejected. Refusing MAIL FROM:<> does not help fight spam, disregards\n"
3519 "RFC requirements, and stops you from receiving standard bounce\n"
3520 "messages. This host does not accept mail from domains whose servers\n"
3523 "Verification failed for <%s>\n%s",
3524 sender_verified_failed->address,
3525 sender_verified_failed->user_message));
3527 fl.rcpt_in_progress = save_rcpt_in_progress;
3530 /* Sort out text for logging */
3532 log_msg = log_msg ? string_sprintf(": %s", log_msg) : US"";
3533 if ((lognl = Ustrchr(log_msg, '\n'))) *lognl = 0;
3535 /* Send permanent failure response to the command, but the code used isn't
3536 always a 5xx one - see comments at the start of this function. If the original
3537 rc was FAIL_DROP we drop the connection and yield 2. */
3540 smtp_respond(smtp_code, codelen, TRUE,
3541 user_msg ? user_msg : US"Administrative prohibition");
3543 /* Send temporary failure response to the command. Don't give any details,
3544 unless acl_temp_details is set. This is TRUE for a callout defer, a "defer"
3545 verb, and for a header verify when smtp_return_error_details is set.
3547 This conditional logic is all somewhat of a mess because of the odd
3548 interactions between temp_details and return_error_details. One day it should
3549 be re-implemented in a tidier fashion. */
3552 if (f.acl_temp_details && user_msg)
3554 if ( smtp_return_error_details
3555 && sender_verified_failed
3556 && sender_verified_failed->message
3558 smtp_respond(smtp_code, codelen, FALSE, sender_verified_failed->message);
3560 smtp_respond(smtp_code, codelen, TRUE, user_msg);
3563 smtp_respond(smtp_code, codelen, TRUE,
3564 US"Temporary local problem - please try later");
3566 /* Log the incident to the logs that are specified by log_reject_target
3567 (default main, reject). This can be empty to suppress logging of rejections. If
3568 the connection is not forcibly to be dropped, return 0. Otherwise, log why it
3569 is closing if required and return 2. */
3571 if (log_reject_target != 0)
3574 gstring * g = s_tlslog(NULL);
3575 uschar * tls = string_from_gstring(g);
3576 if (!tls) tls = US"";
3578 uschar * tls = US"";
3580 log_write(where == ACL_WHERE_CONNECT ? L_connection_reject : 0,
3581 log_reject_target, "%s%s%s %s%srejected %s%s",
3582 LOGGING(dnssec) && sender_host_dnssec ? US" DS" : US"",
3583 host_and_ident(TRUE),
3586 rc == FAIL ? US"" : US"temporarily ",
3590 if (!drop) return 0;
3592 log_close_event(US"by DROP in ACL");
3594 /* Run the not-quit ACL, but without any custom messages. This should not be a
3595 problem, because we get here only if some other ACL has issued "drop", and
3596 in that case, *its* custom messages will have been used above. */
3598 smtp_notquit_exit(US"acl-drop", NULL, NULL);
3600 /* An overenthusiastic fail2ban/iptables implimentation has been seen to result
3601 in the TCP conn staying open, and retrying, despite this process exiting. A
3602 malicious client could possibly do the same, tying up server netowrking
3603 resources. Close the socket explicitly to try to avoid that (there's a note in
3604 the Linux socket(7) manpage, SO_LINGER para, to the effect that exim() without
3605 close() results in the socket always lingering). */
3607 (void) poll_one_fd(fileno(smtp_in), POLLIN, 200);
3608 DEBUG(D_any) debug_printf_indent("SMTP(close)>>\n");
3609 (void) fclose(smtp_in);
3610 (void) fclose(smtp_out);
3618 /*************************************************
3619 * Handle SMTP exit when QUIT is not given *
3620 *************************************************/
3622 /* This function provides a logging/statistics hook for when an SMTP connection
3623 is dropped on the floor or the other end goes away. It's a global function
3624 because it's called from receive.c as well as this module. As well as running
3625 the NOTQUIT ACL, if there is one, this function also outputs a final SMTP
3626 response, either with a custom message from the ACL, or using a default. There
3627 is one case, however, when no message is output - after "drop". In that case,
3628 the ACL that obeyed "drop" has already supplied the custom message, and NULL is
3629 passed to this function.
3631 In case things go wrong while processing this function, causing an error that
3632 may re-enter this function, there is a recursion check.
3635 reason What $smtp_notquit_reason will be set to in the ACL;
3636 if NULL, the ACL is not run
3637 code The error code to return as part of the response
3638 defaultrespond The default message if there's no user_msg
3644 smtp_notquit_exit(uschar *reason, uschar *code, uschar *defaultrespond, ...)
3647 uschar *user_msg = NULL;
3648 uschar *log_msg = NULL;
3650 /* Check for recursive call */
3652 if (fl.smtp_exit_function_called)
3654 log_write(0, LOG_PANIC, "smtp_notquit_exit() called more than once (%s)",
3658 fl.smtp_exit_function_called = TRUE;
3660 /* Call the not-QUIT ACL, if there is one, unless no reason is given. */
3662 if (acl_smtp_notquit && reason)
3664 smtp_notquit_reason = reason;
3665 if ((rc = acl_check(ACL_WHERE_NOTQUIT, NULL, acl_smtp_notquit, &user_msg,
3666 &log_msg)) == ERROR)
3667 log_write(0, LOG_MAIN|LOG_PANIC, "ACL for not-QUIT returned ERROR: %s",
3671 /* If the connection was dropped, we certainly are no longer talking TLS */
3672 tls_in.active.sock = -1;
3674 /* Write an SMTP response if we are expected to give one. As the default
3675 responses are all internal, they should be reasonable size. */
3677 if (code && defaultrespond)
3680 smtp_respond(code, 3, TRUE, user_msg);
3686 va_start(ap, defaultrespond);
3687 g = string_vformat(NULL, SVFMT_EXTEND|SVFMT_REBUFFER, CS defaultrespond, ap);
3689 smtp_printf("%s %s\r\n", FALSE, code, string_from_gstring(g));
3698 /*************************************************
3699 * Verify HELO argument *
3700 *************************************************/
3702 /* This function is called if helo_verify_hosts or helo_try_verify_hosts is
3703 matched. It is also called from ACL processing if verify = helo is used and
3704 verification was not previously tried (i.e. helo_try_verify_hosts was not
3705 matched). The result of its processing is to set helo_verified and
3706 helo_verify_failed. These variables should both be FALSE for this function to
3709 Note that EHLO/HELO is legitimately allowed to quote an address literal. Allow
3710 for IPv6 ::ffff: literals.
3713 Returns: TRUE if testing was completed;
3714 FALSE on a temporary failure
3718 smtp_verify_helo(void)
3722 HDEBUG(D_receive) debug_printf("verifying EHLO/HELO argument \"%s\"\n",
3725 if (sender_helo_name == NULL)
3727 HDEBUG(D_receive) debug_printf("no EHLO/HELO command was issued\n");
3730 /* Deal with the case of -bs without an IP address */
3732 else if (sender_host_address == NULL)
3734 HDEBUG(D_receive) debug_printf("no client IP address: assume success\n");
3735 f.helo_verified = TRUE;
3738 /* Deal with the more common case when there is a sending IP address */
3740 else if (sender_helo_name[0] == '[')
3742 f.helo_verified = Ustrncmp(sender_helo_name+1, sender_host_address,
3743 Ustrlen(sender_host_address)) == 0;
3746 if (!f.helo_verified)
3748 if (strncmpic(sender_host_address, US"::ffff:", 7) == 0)
3749 f.helo_verified = Ustrncmp(sender_helo_name + 1,
3750 sender_host_address + 7, Ustrlen(sender_host_address) - 7) == 0;
3755 { if (f.helo_verified) debug_printf("matched host address\n"); }
3758 /* Do a reverse lookup if one hasn't already given a positive or negative
3759 response. If that fails, or the name doesn't match, try checking with a forward
3764 if (sender_host_name == NULL && !host_lookup_failed)
3765 yield = host_name_lookup() != DEFER;
3767 /* If a host name is known, check it and all its aliases. */
3769 if (sender_host_name)
3770 if ((f.helo_verified = strcmpic(sender_host_name, sender_helo_name) == 0))
3772 sender_helo_dnssec = sender_host_dnssec;
3773 HDEBUG(D_receive) debug_printf("matched host name\n");
3777 uschar **aliases = sender_host_aliases;
3779 if ((f.helo_verified = strcmpic(*aliases++, sender_helo_name) == 0))
3781 sender_helo_dnssec = sender_host_dnssec;
3785 HDEBUG(D_receive) if (f.helo_verified)
3786 debug_printf("matched alias %s\n", *(--aliases));
3789 /* Final attempt: try a forward lookup of the helo name */
3791 if (!f.helo_verified)
3795 {.name = sender_helo_name, .address = NULL, .mx = MX_NONE, .next = NULL};
3797 {.request = US"*", .require = US""};
3799 HDEBUG(D_receive) debug_printf("getting IP address for %s\n",
3801 rc = host_find_bydns(&h, NULL, HOST_FIND_BY_A | HOST_FIND_BY_AAAA,
3802 NULL, NULL, NULL, &d, NULL, NULL);
3803 if (rc == HOST_FOUND || rc == HOST_FOUND_LOCAL)
3804 for (host_item * hh = &h; hh; hh = hh->next)
3805 if (Ustrcmp(hh->address, sender_host_address) == 0)
3807 f.helo_verified = TRUE;
3808 if (h.dnssec == DS_YES) sender_helo_dnssec = TRUE;
3810 debug_printf("IP address for %s matches calling address\n"
3811 "Forward DNS security status: %sverified\n",
3812 sender_helo_name, sender_helo_dnssec ? "" : "un");
3818 if (!f.helo_verified) f.helo_verify_failed = TRUE; /* We've tried ... */
3825 /*************************************************
3826 * Send user response message *
3827 *************************************************/
3829 /* This function is passed a default response code and a user message. It calls
3830 smtp_message_code() to check and possibly modify the response code, and then
3831 calls smtp_respond() to transmit the response. I put this into a function
3832 just to avoid a lot of repetition.
3835 code the response code
3836 user_msg the user message
3842 smtp_user_msg(uschar *code, uschar *user_msg)
3845 smtp_message_code(&code, &len, &user_msg, NULL, TRUE);
3846 smtp_respond(code, len, TRUE, user_msg);
3852 smtp_in_auth(auth_instance *au, uschar ** smtp_resp, uschar ** errmsg)
3854 const uschar *set_id = NULL;
3857 /* Set up globals for error messages */
3859 authenticator_name = au->name;
3860 driver_srcfile = au->srcfile;
3861 driver_srcline = au->srcline;
3863 /* Run the checking code, passing the remainder of the command line as
3864 data. Initials the $auth<n> variables as empty. Initialize $0 empty and set
3865 it as the only set numerical variable. The authenticator may set $auth<n>
3866 and also set other numeric variables. The $auth<n> variables are preferred
3867 nowadays; the numerical variables remain for backwards compatibility.
3869 Afterwards, have a go at expanding the set_id string, even if
3870 authentication failed - for bad passwords it can be useful to log the
3871 userid. On success, require set_id to expand and exist, and put it in
3872 authenticated_id. Save this in permanent store, as the working store gets
3873 reset at HELO, RSET, etc. */
3875 for (int i = 0; i < AUTH_VARS; i++) auth_vars[i] = NULL;
3877 expand_nlength[0] = 0; /* $0 contains nothing */
3879 rc = (au->info->servercode)(au, smtp_cmd_data);
3880 if (au->set_id) set_id = expand_string(au->set_id);
3881 expand_nmax = -1; /* Reset numeric variables */
3882 for (int i = 0; i < AUTH_VARS; i++) auth_vars[i] = NULL; /* Reset $auth<n> */
3883 driver_srcfile = authenticator_name = NULL; driver_srcline = 0;
3885 /* The value of authenticated_id is stored in the spool file and printed in
3886 log lines. It must not contain binary zeros or newline characters. In
3887 normal use, it never will, but when playing around or testing, this error
3888 can (did) happen. To guard against this, ensure that the id contains only
3889 printing characters. */
3891 if (set_id) set_id = string_printing(set_id);
3893 /* For the non-OK cases, set up additional logging data if set_id
3897 set_id = set_id && *set_id
3898 ? string_sprintf(" (set_id=%s)", set_id) : US"";
3900 /* Switch on the result */
3905 if (!au->set_id || set_id) /* Complete success */
3907 if (set_id) authenticated_id = string_copy_perm(set_id, TRUE);
3908 sender_host_authenticated = au->name;
3909 sender_host_auth_pubname = au->public_name;
3910 authentication_failed = FALSE;
3911 authenticated_fail_id = NULL; /* Impossible to already be set? */
3914 (sender_host_address ? protocols : protocols_local)
3915 [pextend + pauthed + (tls_in.active.sock >= 0 ? pcrpted:0)];
3916 *smtp_resp = *errmsg = US"235 Authentication succeeded";
3917 authenticated_by = au;
3921 /* Authentication succeeded, but we failed to expand the set_id string.
3922 Treat this as a temporary error. */
3924 auth_defer_msg = expand_string_message;
3928 if (set_id) authenticated_fail_id = string_copy_perm(set_id, TRUE);
3929 *smtp_resp = string_sprintf("435 Unable to authenticate at present%s",
3930 auth_defer_user_msg);
3931 *errmsg = string_sprintf("435 Unable to authenticate at present%s: %s",
3932 set_id, auth_defer_msg);
3936 *smtp_resp = *errmsg = US"501 Invalid base64 data";
3940 *smtp_resp = *errmsg = US"501 Authentication cancelled";
3944 *smtp_resp = *errmsg = US"553 Initial data not expected";
3948 if (set_id) authenticated_fail_id = string_copy_perm(set_id, TRUE);
3949 *smtp_resp = US"535 Incorrect authentication data";
3950 *errmsg = string_sprintf("535 Incorrect authentication data%s", set_id);
3954 if (set_id) authenticated_fail_id = string_copy_perm(set_id, TRUE);
3955 *smtp_resp = US"435 Internal error";
3956 *errmsg = string_sprintf("435 Internal error%s: return %d from authentication "
3957 "check", set_id, rc);
3969 qualify_recipient(uschar ** recipient, uschar * smtp_cmd_data, uschar * tag)
3972 if (f.allow_unqualified_recipient || strcmpic(*recipient, US"postmaster") == 0)
3974 DEBUG(D_receive) debug_printf("unqualified address %s accepted\n",
3976 rd = Ustrlen(recipient) + 1;
3977 /* deconst ok as *recipient was not const */
3978 *recipient = US rewrite_address_qualify(*recipient, TRUE);
3981 smtp_printf("501 %s: recipient address must contain a domain\r\n", FALSE,
3983 log_write(L_smtp_syntax_error,
3984 LOG_MAIN|LOG_REJECT, "unqualified %s rejected: <%s> %s%s",
3985 tag, *recipient, host_and_ident(TRUE), host_lookup_msg);
3993 smtp_quit_handler(uschar ** user_msgp, uschar ** log_msgp)
3996 f.smtp_in_quit = TRUE;
3997 incomplete_transaction_log(US"QUIT");
3999 && acl_check(ACL_WHERE_QUIT, NULL, acl_smtp_quit, user_msgp, log_msgp)
4001 log_write(0, LOG_MAIN|LOG_PANIC, "ACL for QUIT returned ERROR: %s",
4004 #ifdef EXIM_TCP_CORK
4005 (void) setsockopt(fileno(smtp_out), IPPROTO_TCP, EXIM_TCP_CORK, US &on, sizeof(on));
4009 smtp_respond(US"221", 3, TRUE, *user_msgp);
4011 smtp_printf("221 %s closing connection\r\n", FALSE, smtp_active_hostname);
4013 #ifdef SERVERSIDE_CLOSE_NOWAIT
4014 # ifndef DISABLE_TLS
4015 tls_close(NULL, TLS_SHUTDOWN_NOWAIT);
4018 log_close_event(US"by QUIT");
4021 # ifndef DISABLE_TLS
4022 tls_close(NULL, TLS_SHUTDOWN_WAIT);
4025 log_close_event(US"by QUIT");
4027 /* Pause, hoping client will FIN first so that they get the TIME_WAIT.
4028 The socket should become readble (though with no data) */
4030 (void) poll_one_fd(fileno(smtp_in), POLLIN, 200);
4031 #endif /*!SERVERSIDE_CLOSE_NOWAIT*/
4036 smtp_rset_handler(void)
4039 incomplete_transaction_log(US"RSET");
4040 smtp_printf("250 Reset OK\r\n", FALSE);
4041 cmd_list[CL_RSET].is_mail_cmd = FALSE;
4042 if (chunking_state > CHUNKING_OFFERED)
4043 chunking_state = CHUNKING_OFFERED;
4048 expand_mailmax(const uschar * s)
4050 if (!(s = expand_cstring(s)))
4051 log_write(0, LOG_MAIN|LOG_PANIC, "failed to expand smtp_accept_max_per_connection");
4052 return *s ? Uatoi(s) : 0;
4055 /*************************************************
4056 * Initialize for SMTP incoming message *
4057 *************************************************/
4059 /* This function conducts the initial dialogue at the start of an incoming SMTP
4060 message, and builds a list of recipients. However, if the incoming message
4061 is part of a batch (-bS option) a separate function is called since it would
4062 be messy having tests splattered about all over this function. This function
4063 therefore handles the case where interaction is occurring. The input and output
4064 files are set up in smtp_in and smtp_out.
4066 The global recipients_list is set to point to a vector of recipient_item
4067 blocks, whose number is given by recipients_count. This is extended by the
4068 receive_add_recipient() function. The global variable sender_address is set to
4069 the sender's address. The yield is +1 if a message has been successfully
4070 started, 0 if a QUIT command was encountered or the connection was refused from
4071 the particular host, or -1 if the connection was lost.
4075 Returns: > 0 message successfully started (reached DATA)
4076 = 0 QUIT read or end of file reached or call refused
4081 smtp_setup_msg(void)
4084 BOOL toomany = FALSE;
4085 BOOL discarded = FALSE;
4086 BOOL last_was_rej_mail = FALSE;
4087 BOOL last_was_rcpt = FALSE;
4088 rmark reset_point = store_mark();
4090 DEBUG(D_receive) debug_printf("smtp_setup_msg entered\n");
4092 /* Reset for start of new message. We allow one RSET not to be counted as a
4093 nonmail command, for those MTAs that insist on sending it between every
4094 message. Ditto for EHLO/HELO and for STARTTLS, to allow for going in and out of
4095 TLS between messages (an Exim client may do this if it has messages queued up
4096 for the host). Note: we do NOT reset AUTH at this point. */
4098 reset_point = smtp_reset(reset_point);
4099 message_ended = END_NOTSTARTED;
4101 chunking_state = f.chunking_offered ? CHUNKING_OFFERED : CHUNKING_NOT_OFFERED;
4103 cmd_list[CL_RSET].is_mail_cmd = TRUE;
4104 cmd_list[CL_HELO].is_mail_cmd = TRUE;
4105 cmd_list[CL_EHLO].is_mail_cmd = TRUE;
4107 cmd_list[CL_STLS].is_mail_cmd = TRUE;
4110 if (lwr_receive_getc != NULL)
4112 /* This should have already happened, but if we've gotten confused,
4113 force a reset here. */
4114 DEBUG(D_receive) debug_printf("WARNING: smtp_setup_msg had to restore receive functions to lowers\n");
4115 bdat_pop_receive_functions();
4118 /* Set the local signal handler for SIGTERM - it tries to end off tidily */
4120 had_command_sigterm = 0;
4121 os_non_restarting_signal(SIGTERM, command_sigterm_handler);
4123 /* Batched SMTP is handled in a different function. */
4125 if (smtp_batched_input) return smtp_setup_batch_msg();
4128 if (smtp_in) /* Avoid pure-ACKs while in cmd pingpong phase */
4129 (void) setsockopt(fileno(smtp_in), IPPROTO_TCP, TCP_QUICKACK,
4130 US &off, sizeof(off));
4133 /* Deal with SMTP commands. This loop is exited by setting done to a POSITIVE
4134 value. The values are 2 larger than the required yield of the function. */
4138 const uschar **argv;
4139 uschar *etrn_command;
4140 uschar *etrn_serialize_key;
4142 uschar *log_msg, *smtp_code;
4143 uschar *user_msg = NULL;
4144 uschar *recipient = NULL;
4145 uschar *hello = NULL;
4147 BOOL was_rej_mail = FALSE;
4148 BOOL was_rcpt = FALSE;
4149 void (*oldsignal)(int);
4151 int start, end, sender_domain, recipient_domain;
4154 uschar *orcpt = NULL;
4159 /* Check once per STARTTLS or SSL-on-connect for a TLS AUTH */
4160 if ( tls_in.active.sock >= 0
4162 && tls_in.certificate_verified
4163 && cmd_list[CL_TLAU].is_mail_cmd
4166 cmd_list[CL_TLAU].is_mail_cmd = FALSE;
4168 for (auth_instance * au = auths; au; au = au->next)
4169 if (strcmpic(US"tls", au->driver_name) == 0)
4172 && (rc = acl_check(ACL_WHERE_AUTH, NULL, acl_smtp_auth,
4173 &user_msg, &log_msg)) != OK
4175 done = smtp_handle_acl_fail(ACL_WHERE_AUTH, rc, user_msg, log_msg);
4178 smtp_cmd_data = NULL;
4180 if (smtp_in_auth(au, &s, &ss) == OK)
4181 { DEBUG(D_auth) debug_printf("tls auth succeeded\n"); }
4184 DEBUG(D_auth) debug_printf("tls auth not succeeded\n");
4185 #ifndef DISABLE_EVENT
4187 uschar * save_name = sender_host_authenticated, * logmsg;
4188 sender_host_authenticated = au->name;
4189 if ((logmsg = event_raise(event_action, US"auth:fail", s, NULL)))
4190 log_write(0, LOG_MAIN, "%s", logmsg);
4191 sender_host_authenticated = save_name;
4201 switch(smtp_read_command(
4202 #ifndef DISABLE_PIPE_CONNECT
4203 !fl.pipe_connect_acceptable,
4207 GETC_BUFFER_UNLIMITED))
4209 /* The AUTH command is not permitted to occur inside a transaction, and may
4210 occur successfully only once per connection. Actually, that isn't quite
4211 true. When TLS is started, all previous information about a connection must
4212 be discarded, so a new AUTH is permitted at that time.
4214 AUTH may only be used when it has been advertised. However, it seems that
4215 there are clients that send AUTH when it hasn't been advertised, some of
4216 them even doing this after HELO. And there are MTAs that accept this. Sigh.
4217 So there's a get-out that allows this to happen.
4219 AUTH is initially labelled as a "nonmail command" so that one occurrence
4220 doesn't get counted. We change the label here so that multiple failing
4221 AUTHS will eventually hit the nonmail threshold. */
4225 authentication_failed = TRUE;
4226 cmd_list[CL_AUTH].is_mail_cmd = FALSE;
4228 if (!fl.auth_advertised && !f.allow_auth_unadvertised)
4230 done = synprot_error(L_smtp_protocol_error, 503, NULL,
4231 US"AUTH command used when not advertised");
4234 if (sender_host_authenticated)
4236 done = synprot_error(L_smtp_protocol_error, 503, NULL,
4237 US"already authenticated");
4242 done = synprot_error(L_smtp_protocol_error, 503, NULL,
4243 US"not permitted in mail transaction");
4250 && (rc = acl_check(ACL_WHERE_AUTH, NULL, acl_smtp_auth,
4251 &user_msg, &log_msg)) != OK
4254 done = smtp_handle_acl_fail(ACL_WHERE_AUTH, rc, user_msg, log_msg);
4258 /* Find the name of the requested authentication mechanism. */
4261 for (; (c = *smtp_cmd_data) && !isspace(c); smtp_cmd_data++)
4262 if (!isalnum(c) && c != '-' && c != '_')
4264 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4265 US"invalid character in authentication mechanism name");
4269 /* If not at the end of the line, we must be at white space. Terminate the
4270 name and move the pointer on to any data that may be present. */
4274 *smtp_cmd_data++ = 0;
4275 while (isspace(*smtp_cmd_data)) smtp_cmd_data++;
4278 /* Search for an authentication mechanism which is configured for use
4279 as a server and which has been advertised (unless, sigh, allow_auth_
4280 unadvertised is set). */
4284 uschar * smtp_resp, * errmsg;
4286 for (au = auths; au; au = au->next)
4287 if (strcmpic(s, au->public_name) == 0 && au->server &&
4288 (au->advertised || f.allow_auth_unadvertised))
4293 int rc = smtp_in_auth(au, &smtp_resp, &errmsg);
4295 smtp_printf("%s\r\n", FALSE, smtp_resp);
4298 uschar * logmsg = NULL;
4299 #ifndef DISABLE_EVENT
4300 {uschar * save_name = sender_host_authenticated;
4301 sender_host_authenticated = au->name;
4302 logmsg = event_raise(event_action, US"auth:fail", smtp_resp, NULL);
4303 sender_host_authenticated = save_name;
4307 log_write(0, LOG_MAIN|LOG_REJECT, "%s", logmsg);
4309 log_write(0, LOG_MAIN|LOG_REJECT, "%s authenticator failed for %s: %s",
4310 au->name, host_and_ident(FALSE), errmsg);
4314 done = synprot_error(L_smtp_protocol_error, 504, NULL,
4315 string_sprintf("%s authentication mechanism not supported", s));
4318 break; /* AUTH_CMD */
4320 /* The HELO/EHLO commands are permitted to appear in the middle of a
4321 session as well as at the beginning. They have the effect of a reset in
4322 addition to their other functions. Their absence at the start cannot be
4323 taken to be an error.
4327 If the EHLO command is not acceptable to the SMTP server, 501, 500,
4328 or 502 failure replies MUST be returned as appropriate. The SMTP
4329 server MUST stay in the same state after transmitting these replies
4330 that it was in before the EHLO was received.
4332 Therefore, we do not do the reset until after checking the command for
4333 acceptability. This change was made for Exim release 4.11. Previously
4334 it did the reset first. */
4347 HELO_EHLO: /* Common code for HELO and EHLO */
4348 cmd_list[CL_HELO].is_mail_cmd = FALSE;
4349 cmd_list[CL_EHLO].is_mail_cmd = FALSE;
4351 /* Reject the HELO if its argument was invalid or non-existent. A
4352 successful check causes the argument to be saved in malloc store. */
4354 if (!check_helo(smtp_cmd_data))
4356 smtp_printf("501 Syntactically invalid %s argument(s)\r\n", FALSE, hello);
4358 log_write(0, LOG_MAIN|LOG_REJECT, "rejected %s from %s: syntactically "
4359 "invalid argument(s): %s", hello, host_and_ident(FALSE),
4360 *smtp_cmd_argument == 0 ? US"(no argument given)" :
4361 string_printing(smtp_cmd_argument));
4363 if (++synprot_error_count > smtp_max_synprot_errors)
4365 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
4366 "syntax or protocol errors (last command was \"%s\", %s)",
4367 host_and_ident(FALSE), string_printing(smtp_cmd_buffer),
4368 string_from_gstring(s_connhad_log(NULL))
4376 /* If sender_host_unknown is true, we have got here via the -bs interface,
4377 not called from inetd. Otherwise, we are running an IP connection and the
4378 host address will be set. If the helo name is the primary name of this
4379 host and we haven't done a reverse lookup, force one now. If helo_verify_required
4380 is set, ensure that the HELO name matches the actual host. If helo_verify
4381 is set, do the same check, but softly. */
4383 if (!f.sender_host_unknown)
4385 BOOL old_helo_verified = f.helo_verified;
4386 uschar *p = smtp_cmd_data;
4388 while (*p != 0 && !isspace(*p)) { *p = tolower(*p); p++; }
4391 /* Force a reverse lookup if HELO quoted something in helo_lookup_domains
4392 because otherwise the log can be confusing. */
4394 if ( !sender_host_name
4395 && match_isinlist(sender_helo_name, CUSS &helo_lookup_domains, 0,
4396 &domainlist_anchor, NULL, MCL_DOMAIN, TRUE, NULL) == OK)
4397 (void)host_name_lookup();
4399 /* Rebuild the fullhost info to include the HELO name (and the real name
4400 if it was looked up.) */
4402 host_build_sender_fullhost(); /* Rebuild */
4403 set_process_info("handling%s incoming connection from %s",
4404 tls_in.active.sock >= 0 ? " TLS" : "", host_and_ident(FALSE));
4406 /* Verify if configured. This doesn't give much security, but it does
4407 make some people happy to be able to do it. If helo_verify_required is set,
4408 (host matches helo_verify_hosts) failure forces rejection. If helo_verify
4409 is set (host matches helo_try_verify_hosts), it does not. This is perhaps
4410 now obsolescent, since the verification can now be requested selectively
4413 f.helo_verified = f.helo_verify_failed = sender_helo_dnssec = FALSE;
4414 if (fl.helo_verify_required || fl.helo_verify)
4416 BOOL tempfail = !smtp_verify_helo();
4417 if (!f.helo_verified)
4419 if (fl.helo_verify_required)
4421 smtp_printf("%d %s argument does not match calling host\r\n", FALSE,
4422 tempfail? 451 : 550, hello);
4423 log_write(0, LOG_MAIN|LOG_REJECT, "%srejected \"%s %s\" from %s",
4424 tempfail? "temporarily " : "",
4425 hello, sender_helo_name, host_and_ident(FALSE));
4426 f.helo_verified = old_helo_verified;
4427 break; /* End of HELO/EHLO processing */
4429 HDEBUG(D_all) debug_printf("%s verification failed but host is in "
4430 "helo_try_verify_hosts\n", hello);
4436 /* set up SPF context */
4437 spf_conn_init(sender_helo_name, sender_host_address);
4440 /* Apply an ACL check if one is defined; afterwards, recheck
4441 synchronization in case the client started sending in a delay. */
4444 if ((rc = acl_check(ACL_WHERE_HELO, NULL, acl_smtp_helo,
4445 &user_msg, &log_msg)) != OK)
4447 done = smtp_handle_acl_fail(ACL_WHERE_HELO, rc, user_msg, log_msg);
4448 sender_helo_name = NULL;
4449 host_build_sender_fullhost(); /* Rebuild */
4452 #ifndef DISABLE_PIPE_CONNECT
4453 else if (!fl.pipe_connect_acceptable && !check_sync())
4455 else if (!check_sync())
4459 /* Generate an OK reply. The default string includes the ident if present,
4460 and also the IP address if present. Reflecting back the ident is intended
4461 as a deterrent to mail forgers. For maximum efficiency, and also because
4462 some broken systems expect each response to be in a single packet, arrange
4463 that the entire reply is sent in one write(). */
4465 fl.auth_advertised = FALSE;
4466 f.smtp_in_pipelining_advertised = FALSE;
4468 fl.tls_advertised = FALSE;
4470 fl.dsn_advertised = FALSE;
4472 fl.smtputf8_advertised = FALSE;
4475 /* Expand the per-connection message count limit option */
4476 smtp_mailcmd_max = expand_mailmax(smtp_accept_max_per_connection);
4478 smtp_code = US"250 "; /* Default response code plus space*/
4481 /* sender_host_name below will be tainted, so save on copy when we hit it */
4482 g = string_get_tainted(24, GET_TAINTED);
4483 g = string_fmt_append(g, "%.3s %s Hello %s%s%s",
4485 smtp_active_hostname,
4486 sender_ident ? sender_ident : US"",
4487 sender_ident ? US" at " : US"",
4488 sender_host_name ? sender_host_name : sender_helo_name);
4490 if (sender_host_address)
4491 g = string_fmt_append(g, " [%s]", sender_host_address);
4494 /* A user-supplied EHLO greeting may not contain more than one line. Note
4495 that the code returned by smtp_message_code() includes the terminating
4496 whitespace character. */
4502 smtp_message_code(&smtp_code, &codelen, &user_msg, NULL, TRUE);
4503 s = string_sprintf("%.*s%s", codelen, smtp_code, user_msg);
4504 if ((ss = strpbrk(CS s, "\r\n")) != NULL)
4506 log_write(0, LOG_MAIN|LOG_PANIC, "EHLO/HELO response must not contain "
4507 "newlines: message truncated: %s", string_printing(s));
4510 g = string_cat(NULL, s);
4513 g = string_catn(g, US"\r\n", 2);
4515 /* If we received EHLO, we must create a multiline response which includes
4516 the functions supported. */
4520 g->s[3] = '-'; /* overwrite the space after the SMTP response code */
4522 /* I'm not entirely happy with this, as an MTA is supposed to check
4523 that it has enough room to accept a message of maximum size before
4524 it sends this. However, there seems little point in not sending it.
4525 The actual size check happens later at MAIL FROM time. By postponing it
4526 till then, VRFY and EXPN can be used after EHLO when space is short. */
4528 if (thismessage_size_limit > 0)
4529 g = string_fmt_append(g, "%.3s-SIZE %d\r\n", smtp_code,
4530 thismessage_size_limit);
4533 g = string_catn(g, smtp_code, 3);
4534 g = string_catn(g, US"-SIZE\r\n", 7);
4537 #ifdef EXPERIMENTAL_ESMTP_LIMITS
4538 if ( (smtp_mailcmd_max > 0 || recipients_max)
4539 && verify_check_host(&limits_advertise_hosts) == OK)
4541 g = string_fmt_append(g, "%.3s-LIMITS", smtp_code);
4542 if (smtp_mailcmd_max > 0)
4543 g = string_fmt_append(g, " MAILMAX=%d", smtp_mailcmd_max);
4545 g = string_fmt_append(g, " RCPTMAX=%d", recipients_max);
4546 g = string_catn(g, US"\r\n", 2);
4550 /* Exim does not do protocol conversion or data conversion. It is 8-bit
4551 clean; if it has an 8-bit character in its hand, it just sends it. It
4552 cannot therefore specify 8BITMIME and remain consistent with the RFCs.
4553 However, some users want this option simply in order to stop MUAs
4554 mangling messages that contain top-bit-set characters. It is therefore
4555 provided as an option. */
4557 if (accept_8bitmime)
4559 g = string_catn(g, smtp_code, 3);
4560 g = string_catn(g, US"-8BITMIME\r\n", 11);
4563 /* Advertise DSN support if configured to do so. */
4564 if (verify_check_host(&dsn_advertise_hosts) != FAIL)
4566 g = string_catn(g, smtp_code, 3);
4567 g = string_catn(g, US"-DSN\r\n", 6);
4568 fl.dsn_advertised = TRUE;
4571 /* Advertise ETRN/VRFY/EXPN if there's are ACL checking whether a host is
4572 permitted to issue them; a check is made when any host actually tries. */
4576 g = string_catn(g, smtp_code, 3);
4577 g = string_catn(g, US"-ETRN\r\n", 7);
4581 g = string_catn(g, smtp_code, 3);
4582 g = string_catn(g, US"-VRFY\r\n", 7);
4586 g = string_catn(g, smtp_code, 3);
4587 g = string_catn(g, US"-EXPN\r\n", 7);
4590 /* Exim is quite happy with pipelining, so let the other end know that
4591 it is safe to use it, unless advertising is disabled. */
4593 if ( f.pipelining_enable
4594 && verify_check_host(&pipelining_advertise_hosts) == OK)
4596 g = string_catn(g, smtp_code, 3);
4597 g = string_catn(g, US"-PIPELINING\r\n", 13);
4598 sync_cmd_limit = NON_SYNC_CMD_PIPELINING;
4599 f.smtp_in_pipelining_advertised = TRUE;
4601 #ifndef DISABLE_PIPE_CONNECT
4602 if (fl.pipe_connect_acceptable)
4604 f.smtp_in_early_pipe_advertised = TRUE;
4605 g = string_catn(g, smtp_code, 3);
4606 g = string_catn(g, US"-" EARLY_PIPE_FEATURE_NAME "\r\n", EARLY_PIPE_FEATURE_LEN+3);
4612 /* If any server authentication mechanisms are configured, advertise
4613 them if the current host is in auth_advertise_hosts. The problem with
4614 advertising always is that some clients then require users to
4615 authenticate (and aren't configurable otherwise) even though it may not
4616 be necessary (e.g. if the host is in host_accept_relay).
4618 RFC 2222 states that SASL mechanism names contain only upper case
4619 letters, so output the names in upper case, though we actually recognize
4620 them in either case in the AUTH command. */
4624 && !sender_host_authenticated
4626 && verify_check_host(&auth_advertise_hosts) == OK
4630 for (auth_instance * au = auths; au; au = au->next)
4632 au->advertised = FALSE;
4635 DEBUG(D_auth+D_expand) debug_printf_indent(
4636 "Evaluating advertise_condition for %s %s athenticator\n",
4637 au->name, au->public_name);
4638 if ( !au->advertise_condition
4639 || expand_check_condition(au->advertise_condition, au->name,
4646 g = string_catn(g, smtp_code, 3);
4647 g = string_catn(g, US"-AUTH", 5);
4649 fl.auth_advertised = TRUE;
4651 saveptr = gstring_length(g);
4652 g = string_catn(g, US" ", 1);
4653 g = string_cat(g, au->public_name);
4654 while (++saveptr < g->ptr) g->s[saveptr] = toupper(g->s[saveptr]);
4655 au->advertised = TRUE;
4660 if (!first) g = string_catn(g, US"\r\n", 2);
4663 /* RFC 3030 CHUNKING */
4665 if (verify_check_host(&chunking_advertise_hosts) != FAIL)
4667 g = string_catn(g, smtp_code, 3);
4668 g = string_catn(g, US"-CHUNKING\r\n", 11);
4669 f.chunking_offered = TRUE;
4670 chunking_state = CHUNKING_OFFERED;
4673 /* Advertise TLS (Transport Level Security) aka SSL (Secure Socket Layer)
4674 if it has been included in the binary, and the host matches
4675 tls_advertise_hosts. We must *not* advertise if we are already in a
4676 secure connection. */
4679 if (tls_in.active.sock < 0 &&
4680 verify_check_host(&tls_advertise_hosts) != FAIL)
4682 g = string_catn(g, smtp_code, 3);
4683 g = string_catn(g, US"-STARTTLS\r\n", 11);
4684 fl.tls_advertised = TRUE;
4688 #ifndef DISABLE_PRDR
4689 /* Per Recipient Data Response, draft by Eric A. Hall extending RFC */
4692 g = string_catn(g, smtp_code, 3);
4693 g = string_catn(g, US"-PRDR\r\n", 7);
4698 if ( accept_8bitmime
4699 && verify_check_host(&smtputf8_advertise_hosts) != FAIL)
4701 g = string_catn(g, smtp_code, 3);
4702 g = string_catn(g, US"-SMTPUTF8\r\n", 11);
4703 fl.smtputf8_advertised = TRUE;
4707 /* Finish off the multiline reply with one that is always available. */
4709 g = string_catn(g, smtp_code, 3);
4710 g = string_catn(g, US" HELP\r\n", 7);
4713 /* Terminate the string (for debug), write it, and note that HELO/EHLO
4718 int len = len_string_from_gstring(g, &ehlo_resp);
4720 if (tls_in.active.sock >= 0)
4721 (void) tls_write(NULL, ehlo_resp, len,
4722 # ifndef DISABLE_PIPE_CONNECT
4723 fl.pipe_connect_acceptable && pipeline_connect_sends());
4729 (void) fwrite(ehlo_resp, 1, len, smtp_out);
4731 DEBUG(D_receive) for (const uschar * t, * s = ehlo_resp;
4732 s && (t = Ustrchr(s, '\r'));
4733 s = t + 2) /* \r\n */
4734 debug_printf("%s %.*s\n",
4735 s == g->s ? "SMTP>>" : " ",
4737 fl.helo_seen = TRUE;
4740 /* Reset the protocol and the state, abandoning any previous message. */
4742 (sender_host_address ? protocols : protocols_local)
4744 ? pextend + (sender_host_authenticated ? pauthed : 0)
4746 + (tls_in.active.sock >= 0 ? pcrpted : 0)
4748 cancel_cutthrough_connection(TRUE, US"sent EHLO response");
4749 reset_point = smtp_reset(reset_point);
4751 break; /* HELO/EHLO */
4754 /* The MAIL command requires an address as an operand. All we do
4755 here is to parse it for syntactic correctness. The form "<>" is
4756 a special case which converts into an empty string. The start/end
4757 pointers in the original are not used further for this address, as
4758 it is the canonical extracted address which is all that is kept. */
4762 smtp_mailcmd_count++; /* Count for limit and ratelimit */
4764 was_rej_mail = TRUE; /* Reset if accepted */
4765 env_mail_type_t * mail_args; /* Sanity check & validate args */
4768 if ( fl.helo_verify_required
4769 || verify_check_host(&hosts_require_helo) == OK)
4771 smtp_printf("503 HELO or EHLO required\r\n", FALSE);
4772 log_write(0, LOG_MAIN|LOG_REJECT, "rejected MAIL from %s: no "
4773 "HELO/EHLO given", host_and_ident(FALSE));
4776 else if (smtp_mailcmd_max < 0)
4777 smtp_mailcmd_max = expand_mailmax(smtp_accept_max_per_connection);
4781 done = synprot_error(L_smtp_protocol_error, 503, NULL,
4782 US"sender already given");
4786 if (!*smtp_cmd_data)
4788 done = synprot_error(L_smtp_protocol_error, 501, NULL,
4789 US"MAIL must have an address operand");
4793 /* Check to see if the limit for messages per connection would be
4794 exceeded by accepting further messages. */
4796 if (smtp_mailcmd_max > 0 && smtp_mailcmd_count > smtp_mailcmd_max)
4798 smtp_printf("421 too many messages in this connection\r\n", FALSE);
4799 log_write(0, LOG_MAIN|LOG_REJECT, "rejected MAIL command %s: too many "
4800 "messages in one connection", host_and_ident(TRUE));
4804 /* Reset for start of message - even if this is going to fail, we
4805 obviously need to throw away any previous data. */
4807 cancel_cutthrough_connection(TRUE, US"MAIL received");
4808 reset_point = smtp_reset(reset_point);
4810 sender_data = recipient_data = NULL;
4812 /* Loop, checking for ESMTP additions to the MAIL FROM command. */
4814 if (fl.esmtp) for(;;)
4816 uschar *name, *value, *end;
4817 unsigned long int size;
4818 BOOL arg_error = FALSE;
4820 if (!extract_option(&name, &value)) break;
4822 for (mail_args = env_mail_type_list;
4823 mail_args->value != ENV_MAIL_OPT_NULL;
4826 if (strcmpic(name, mail_args->name) == 0)
4828 if (mail_args->need_value && strcmpic(value, US"") == 0)
4831 switch(mail_args->value)
4833 /* Handle SIZE= by reading the value. We don't do the check till later,
4834 in order to be able to log the sender address on failure. */
4835 case ENV_MAIL_OPT_SIZE:
4836 if (((size = Ustrtoul(value, &end, 10)), *end == 0))
4838 if ((size == ULONG_MAX && errno == ERANGE) || size > INT_MAX)
4840 message_size = (int)size;
4846 /* If this session was initiated with EHLO and accept_8bitmime is set,
4847 Exim will have indicated that it supports the BODY=8BITMIME option. In
4848 fact, it does not support this according to the RFCs, in that it does not
4849 take any special action for forwarding messages containing 8-bit
4850 characters. That is why accept_8bitmime is not the default setting, but
4851 some sites want the action that is provided. We recognize both "8BITMIME"
4852 and "7BIT" as body types, but take no action. */
4853 case ENV_MAIL_OPT_BODY:
4854 if (accept_8bitmime) {
4855 if (strcmpic(value, US"8BITMIME") == 0)
4857 else if (strcmpic(value, US"7BIT") == 0)
4862 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4863 US"invalid data for BODY");
4866 DEBUG(D_receive) debug_printf("8BITMIME: %d\n", body_8bitmime);
4872 /* Handle the two DSN options, but only if configured to do so (which
4873 will have caused "DSN" to be given in the EHLO response). The code itself
4874 is included only if configured in at build time. */
4876 case ENV_MAIL_OPT_RET:
4877 if (fl.dsn_advertised)
4879 /* Check if RET has already been set */
4882 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4883 US"RET can be specified once only");
4886 dsn_ret = strcmpic(value, US"HDRS") == 0
4888 : strcmpic(value, US"FULL") == 0
4891 DEBUG(D_receive) debug_printf("DSN_RET: %d\n", dsn_ret);
4892 /* Check for invalid invalid value, and exit with error */
4895 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4896 US"Value for RET is invalid");
4901 case ENV_MAIL_OPT_ENVID:
4902 if (fl.dsn_advertised)
4904 /* Check if the dsn envid has been already set */
4907 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4908 US"ENVID can be specified once only");
4911 dsn_envid = string_copy(value);
4912 DEBUG(D_receive) debug_printf("DSN_ENVID: %s\n", dsn_envid);
4916 /* Handle the AUTH extension. If the value given is not "<>" and either
4917 the ACL says "yes" or there is no ACL but the sending host is
4918 authenticated, we set it up as the authenticated sender. However, if the
4919 authenticator set a condition to be tested, we ignore AUTH on MAIL unless
4920 the condition is met. The value of AUTH is an xtext, which means that +,
4921 = and cntrl chars are coded in hex; however "<>" is unaffected by this
4923 case ENV_MAIL_OPT_AUTH:
4924 if (Ustrcmp(value, "<>") != 0)
4929 if (auth_xtextdecode(value, &authenticated_sender) < 0)
4931 /* Put back terminator overrides for error message */
4934 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4935 US"invalid data for AUTH");
4938 if (!acl_smtp_mailauth)
4940 ignore_msg = US"client not authenticated";
4941 rc = sender_host_authenticated ? OK : FAIL;
4945 ignore_msg = US"rejected by ACL";
4946 rc = acl_check(ACL_WHERE_MAILAUTH, NULL, acl_smtp_mailauth,
4947 &user_msg, &log_msg);
4953 if (authenticated_by == NULL ||
4954 authenticated_by->mail_auth_condition == NULL ||
4955 expand_check_condition(authenticated_by->mail_auth_condition,
4956 authenticated_by->name, US"authenticator"))
4957 break; /* Accept the AUTH */
4959 ignore_msg = US"server_mail_auth_condition failed";
4960 if (authenticated_id != NULL)
4961 ignore_msg = string_sprintf("%s: authenticated ID=\"%s\"",
4962 ignore_msg, authenticated_id);
4967 authenticated_sender = NULL;
4968 log_write(0, LOG_MAIN, "ignoring AUTH=%s from %s (%s)",
4969 value, host_and_ident(TRUE), ignore_msg);
4972 /* Should only get DEFER or ERROR here. Put back terminator
4973 overrides for error message */
4978 (void)smtp_handle_acl_fail(ACL_WHERE_MAILAUTH, rc, user_msg,
4985 #ifndef DISABLE_PRDR
4986 case ENV_MAIL_OPT_PRDR:
4988 prdr_requested = TRUE;
4993 case ENV_MAIL_OPT_UTF8:
4994 if (!fl.smtputf8_advertised)
4996 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4997 US"SMTPUTF8 used when not advertised");
5001 DEBUG(D_receive) debug_printf("smtputf8 requested\n");
5002 message_smtputf8 = allow_utf8_domains = TRUE;
5003 if (Ustrncmp(received_protocol, US"utf8", 4) != 0)
5005 int old_pool = store_pool;
5006 store_pool = POOL_PERM;
5007 received_protocol = string_sprintf("utf8%s", received_protocol);
5008 store_pool = old_pool;
5013 /* No valid option. Stick back the terminator characters and break
5014 the loop. Do the name-terminator second as extract_option sets
5015 value==name when it found no equal-sign.
5016 An error for a malformed address will occur. */
5017 case ENV_MAIL_OPT_NULL:
5025 /* Break out of for loop if switch() had bad argument or
5026 when start of the email address is reached */
5027 if (arg_error) break;
5030 /* If we have passed the threshold for rate limiting, apply the current
5031 delay, and update it for next time, provided this is a limited host. */
5033 if (smtp_mailcmd_count > smtp_rlm_threshold &&
5034 verify_check_host(&smtp_ratelimit_hosts) == OK)
5036 DEBUG(D_receive) debug_printf("rate limit MAIL: delay %.3g sec\n",
5037 smtp_delay_mail/1000.0);
5038 millisleep((int)smtp_delay_mail);
5039 smtp_delay_mail *= smtp_rlm_factor;
5040 if (smtp_delay_mail > (double)smtp_rlm_limit)
5041 smtp_delay_mail = (double)smtp_rlm_limit;
5044 /* Now extract the address, first applying any SMTP-time rewriting. The
5045 TRUE flag allows "<>" as a sender address. */
5047 raw_sender = rewrite_existflags & rewrite_smtp
5048 /* deconst ok as smtp_cmd_data was not const */
5049 ? US rewrite_one(smtp_cmd_data, rewrite_smtp, NULL, FALSE, US"",
5050 global_rewrite_rules)
5054 parse_extract_address(raw_sender, &errmess, &start, &end, &sender_domain,
5059 done = synprot_error(L_smtp_syntax_error, 501, smtp_cmd_data, errmess);
5063 sender_address = raw_sender;
5065 /* If there is a configured size limit for mail, check that this message
5066 doesn't exceed it. The check is postponed to this point so that the sender
5069 if (thismessage_size_limit > 0 && message_size > thismessage_size_limit)
5071 smtp_printf("552 Message size exceeds maximum permitted\r\n", FALSE);
5072 log_write(L_size_reject,
5073 LOG_MAIN|LOG_REJECT, "rejected MAIL FROM:<%s> %s: "
5074 "message too big: size%s=%d max=%d",
5076 host_and_ident(TRUE),
5077 (message_size == INT_MAX)? ">" : "",
5079 thismessage_size_limit);
5080 sender_address = NULL;
5084 /* Check there is enough space on the disk unless configured not to.
5085 When smtp_check_spool_space is set, the check is for thismessage_size_limit
5086 plus the current message - i.e. we accept the message only if it won't
5087 reduce the space below the threshold. Add 5000 to the size to allow for
5088 overheads such as the Received: line and storing of recipients, etc.
5089 By putting the check here, even when SIZE is not given, it allow VRFY
5090 and EXPN etc. to be used when space is short. */
5092 if (!receive_check_fs(
5093 smtp_check_spool_space && message_size >= 0
5094 ? message_size + 5000 : 0))
5096 smtp_printf("452 Space shortage, please try later\r\n", FALSE);
5097 sender_address = NULL;
5101 /* If sender_address is unqualified, reject it, unless this is a locally
5102 generated message, or the sending host or net is permitted to send
5103 unqualified addresses - typically local machines behaving as MUAs -
5104 in which case just qualify the address. The flag is set above at the start
5105 of the SMTP connection. */
5107 if (!sender_domain && *sender_address)
5108 if (f.allow_unqualified_sender)
5110 sender_domain = Ustrlen(sender_address) + 1;
5111 /* deconst ok as sender_address was not const */
5112 sender_address = US rewrite_address_qualify(sender_address, FALSE);
5113 DEBUG(D_receive) debug_printf("unqualified address %s accepted\n",
5118 smtp_printf("501 %s: sender address must contain a domain\r\n", FALSE,
5120 log_write(L_smtp_syntax_error,
5121 LOG_MAIN|LOG_REJECT,
5122 "unqualified sender rejected: <%s> %s%s",
5124 host_and_ident(TRUE),
5126 sender_address = NULL;
5130 /* Apply an ACL check if one is defined, before responding. Afterwards,
5131 when pipelining is not advertised, do another sync check in case the ACL
5132 delayed and the client started sending in the meantime. */
5136 rc = acl_check(ACL_WHERE_MAIL, NULL, acl_smtp_mail, &user_msg, &log_msg);
5137 if (rc == OK && !f.smtp_in_pipelining_advertised && !check_sync())
5143 if (rc == OK || rc == DISCARD)
5145 BOOL more = pipeline_response();
5148 smtp_printf("%s%s%s", more, US"250 OK",
5149 #ifndef DISABLE_PRDR
5150 prdr_requested ? US", PRDR Requested" : US"",
5157 #ifndef DISABLE_PRDR
5159 user_msg = string_sprintf("%s%s", user_msg, US", PRDR Requested");
5161 smtp_user_msg(US"250", user_msg);
5163 smtp_delay_rcpt = smtp_rlr_base;
5164 f.recipients_discarded = (rc == DISCARD);
5165 was_rej_mail = FALSE;
5169 done = smtp_handle_acl_fail(ACL_WHERE_MAIL, rc, user_msg, log_msg);
5170 sender_address = NULL;
5175 /* The RCPT command requires an address as an operand. There may be any
5176 number of RCPT commands, specifying multiple recipients. We build them all
5177 into a data structure. The start/end values given by parse_extract_address
5178 are not used, as we keep only the extracted address. */
5182 /* We got really to many recipients. A check against configured
5183 limits is done later */
5184 if (rcpt_count < 0 || rcpt_count >= INT_MAX/2)
5185 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "Too many recipients: %d", rcpt_count);
5187 was_rcpt = fl.rcpt_in_progress = TRUE;
5189 /* There must be a sender address; if the sender was rejected and
5190 pipelining was advertised, we assume the client was pipelining, and do not
5191 count this as a protocol error. Reset was_rej_mail so that further RCPTs
5192 get the same treatment. */
5194 if (!sender_address)
5196 if (f.smtp_in_pipelining_advertised && last_was_rej_mail)
5198 smtp_printf("503 sender not yet given\r\n", FALSE);
5199 was_rej_mail = TRUE;
5203 done = synprot_error(L_smtp_protocol_error, 503, NULL,
5204 US"sender not yet given");
5205 was_rcpt = FALSE; /* Not a valid RCPT */
5211 /* Check for an operand */
5213 if (!smtp_cmd_data[0])
5215 done = synprot_error(L_smtp_syntax_error, 501, NULL,
5216 US"RCPT must have an address operand");
5221 /* Set the DSN flags orcpt and dsn_flags from the session*/
5225 if (fl.esmtp) for(;;)
5227 uschar *name, *value;
5229 if (!extract_option(&name, &value))
5232 if (fl.dsn_advertised && strcmpic(name, US"ORCPT") == 0)
5234 /* Check whether orcpt has been already set */
5237 done = synprot_error(L_smtp_syntax_error, 501, NULL,
5238 US"ORCPT can be specified once only");
5241 orcpt = string_copy(value);
5242 DEBUG(D_receive) debug_printf("DSN orcpt: %s\n", orcpt);
5245 else if (fl.dsn_advertised && strcmpic(name, US"NOTIFY") == 0)
5247 /* Check if the notify flags have been already set */
5250 done = synprot_error(L_smtp_syntax_error, 501, NULL,
5251 US"NOTIFY can be specified once only");
5254 if (strcmpic(value, US"NEVER") == 0)
5255 dsn_flags |= rf_notify_never;
5262 while (*pp != 0 && *pp != ',') pp++;
5263 if (*pp == ',') *pp++ = 0;
5264 if (strcmpic(p, US"SUCCESS") == 0)
5266 DEBUG(D_receive) debug_printf("DSN: Setting notify success\n");
5267 dsn_flags |= rf_notify_success;
5269 else if (strcmpic(p, US"FAILURE") == 0)
5271 DEBUG(D_receive) debug_printf("DSN: Setting notify failure\n");
5272 dsn_flags |= rf_notify_failure;
5274 else if (strcmpic(p, US"DELAY") == 0)
5276 DEBUG(D_receive) debug_printf("DSN: Setting notify delay\n");
5277 dsn_flags |= rf_notify_delay;
5281 /* Catch any strange values */
5282 done = synprot_error(L_smtp_syntax_error, 501, NULL,
5283 US"Invalid value for NOTIFY parameter");
5288 DEBUG(D_receive) debug_printf("DSN Flags: %x\n", dsn_flags);
5292 /* Unknown option. Stick back the terminator characters and break
5293 the loop. An error for a malformed address will occur. */
5297 DEBUG(D_receive) debug_printf("Invalid RCPT option: %s : %s\n", name, value);
5304 /* Apply SMTP rewriting then extract the working address. Don't allow "<>"
5305 as a recipient address */
5307 recipient = rewrite_existflags & rewrite_smtp
5308 /* deconst ok as smtp_cmd_data was not const */
5309 ? US rewrite_one(smtp_cmd_data, rewrite_smtp, NULL, FALSE, US"",
5310 global_rewrite_rules)
5313 if (!(recipient = parse_extract_address(recipient, &errmess, &start, &end,
5314 &recipient_domain, FALSE)))
5316 done = synprot_error(L_smtp_syntax_error, 501, smtp_cmd_data, errmess);
5321 /* If the recipient address is unqualified, reject it, unless this is a
5322 locally generated message. However, unqualified addresses are permitted
5323 from a configured list of hosts and nets - typically when behaving as
5324 MUAs rather than MTAs. Sad that SMTP is used for both types of traffic,
5325 really. The flag is set at the start of the SMTP connection.
5327 RFC 1123 talks about supporting "the reserved mailbox postmaster"; I always
5328 assumed this meant "reserved local part", but the revision of RFC 821 and
5329 friends now makes it absolutely clear that it means *mailbox*. Consequently
5330 we must always qualify this address, regardless. */
5332 if (!recipient_domain)
5333 if (!(recipient_domain = qualify_recipient(&recipient, smtp_cmd_data,
5340 /* Check maximum allowed */
5342 if (rcpt_count+1 < 0 || rcpt_count > recipients_max && recipients_max > 0)
5344 if (recipients_max_reject)
5347 smtp_printf("552 too many recipients\r\n", FALSE);
5349 log_write(0, LOG_MAIN|LOG_REJECT, "too many recipients: message "
5350 "rejected: sender=<%s> %s", sender_address, host_and_ident(TRUE));
5355 smtp_printf("452 too many recipients\r\n", FALSE);
5357 log_write(0, LOG_MAIN|LOG_REJECT, "too many recipients: excess "
5358 "temporarily rejected: sender=<%s> %s", sender_address,
5359 host_and_ident(TRUE));
5366 /* If we have passed the threshold for rate limiting, apply the current
5367 delay, and update it for next time, provided this is a limited host. */
5369 if (rcpt_count > smtp_rlr_threshold &&
5370 verify_check_host(&smtp_ratelimit_hosts) == OK)
5372 DEBUG(D_receive) debug_printf("rate limit RCPT: delay %.3g sec\n",
5373 smtp_delay_rcpt/1000.0);
5374 millisleep((int)smtp_delay_rcpt);
5375 smtp_delay_rcpt *= smtp_rlr_factor;
5376 if (smtp_delay_rcpt > (double)smtp_rlr_limit)
5377 smtp_delay_rcpt = (double)smtp_rlr_limit;
5380 /* If the MAIL ACL discarded all the recipients, we bypass ACL checking
5381 for them. Otherwise, check the access control list for this recipient. As
5382 there may be a delay in this, re-check for a synchronization error
5383 afterwards, unless pipelining was advertised. */
5385 if (f.recipients_discarded)
5388 if ( (rc = acl_check(ACL_WHERE_RCPT, recipient, acl_smtp_rcpt, &user_msg,
5390 && !f.smtp_in_pipelining_advertised && !check_sync())
5393 /* The ACL was happy */
5397 BOOL more = pipeline_response();
5400 smtp_user_msg(US"250", user_msg);
5402 smtp_printf("250 Accepted\r\n", more);
5403 receive_add_recipient(recipient, -1);
5405 /* Set the dsn flags in the recipients_list */
5406 recipients_list[recipients_count-1].orcpt = orcpt;
5407 recipients_list[recipients_count-1].dsn_flags = dsn_flags;
5409 /* DEBUG(D_receive) debug_printf("DSN: orcpt: %s flags: %d\n",
5410 recipients_list[recipients_count-1].orcpt,
5411 recipients_list[recipients_count-1].dsn_flags); */
5414 /* The recipient was discarded */
5416 else if (rc == DISCARD)
5419 smtp_user_msg(US"250", user_msg);
5421 smtp_printf("250 Accepted\r\n", FALSE);
5424 log_write(0, LOG_MAIN|LOG_REJECT, "%s F=<%s> RCPT %s: "
5425 "discarded by %s ACL%s%s", host_and_ident(TRUE),
5426 sender_address_unrewritten ? sender_address_unrewritten : sender_address,
5427 smtp_cmd_argument, f.recipients_discarded ? "MAIL" : "RCPT",
5428 log_msg ? US": " : US"", log_msg ? log_msg : US"");
5431 /* Either the ACL failed the address, or it was deferred. */
5435 if (rc == FAIL) rcpt_fail_count++; else rcpt_defer_count++;
5436 done = smtp_handle_acl_fail(ACL_WHERE_RCPT, rc, user_msg, log_msg);
5441 /* The DATA command is legal only if it follows successful MAIL FROM
5442 and RCPT TO commands. However, if pipelining is advertised, a bad DATA is
5443 not counted as a protocol error if it follows RCPT (which must have been
5444 rejected if there are no recipients.) This function is complete when a
5445 valid DATA command is encountered.
5447 Note concerning the code used: RFC 2821 says this:
5449 - If there was no MAIL, or no RCPT, command, or all such commands
5450 were rejected, the server MAY return a "command out of sequence"
5451 (503) or "no valid recipients" (554) reply in response to the
5454 The example in the pipelining RFC 2920 uses 554, but I use 503 here
5455 because it is the same whether pipelining is in use or not.
5457 If all the RCPT commands that precede DATA provoked the same error message
5458 (often indicating some kind of system error), it is helpful to include it
5459 with the DATA rejection (an idea suggested by Tony Finch). */
5466 if (chunking_state != CHUNKING_OFFERED)
5468 done = synprot_error(L_smtp_protocol_error, 503, NULL,
5469 US"BDAT command used when CHUNKING not advertised");
5473 /* grab size, endmarker */
5475 if (sscanf(CS smtp_cmd_data, "%u %n", &chunking_datasize, &n) < 1)
5477 done = synprot_error(L_smtp_protocol_error, 501, NULL,
5478 US"missing size for BDAT command");
5481 chunking_state = strcmpic(smtp_cmd_data+n, US"LAST") == 0
5482 ? CHUNKING_LAST : CHUNKING_ACTIVE;
5483 chunking_data_left = chunking_datasize;
5484 DEBUG(D_receive) debug_printf("chunking state %d, %d bytes\n",
5485 (int)chunking_state, chunking_data_left);
5487 f.bdat_readers_wanted = TRUE; /* FIXME: redundant vs chunking_state? */
5496 f.bdat_readers_wanted = FALSE;
5498 DATA_BDAT: /* Common code for DATA and BDAT */
5499 #ifndef DISABLE_PIPE_CONNECT
5500 fl.pipe_connect_acceptable = FALSE;
5502 if (!discarded && recipients_count <= 0)
5504 if (fl.rcpt_smtp_response_same && rcpt_smtp_response)
5506 uschar *code = US"503";
5507 int len = Ustrlen(rcpt_smtp_response);
5508 smtp_respond(code, 3, FALSE, US"All RCPT commands were rejected with "
5510 /* Responses from smtp_printf() will have \r\n on the end */
5511 if (len > 2 && rcpt_smtp_response[len-2] == '\r')
5512 rcpt_smtp_response[len-2] = 0;
5513 smtp_respond(code, 3, FALSE, rcpt_smtp_response);
5515 if (f.smtp_in_pipelining_advertised && last_was_rcpt)
5516 smtp_printf("503 Valid RCPT command must precede %s\r\n", FALSE,
5517 smtp_names[smtp_connection_had[SMTP_HBUFF_PREV(smtp_ch_index)]]);
5519 done = synprot_error(L_smtp_protocol_error, 503, NULL,
5520 smtp_connection_had[SMTP_HBUFF_PREV(smtp_ch_index)] == SCH_DATA
5521 ? US"valid RCPT command must precede DATA"
5522 : US"valid RCPT command must precede BDAT");
5524 if (chunking_state > CHUNKING_OFFERED)
5526 bdat_push_receive_functions();
5532 if (toomany && recipients_max_reject)
5534 sender_address = NULL; /* This will allow a new MAIL without RSET */
5535 sender_address_unrewritten = NULL;
5536 smtp_printf("554 Too many recipients\r\n", FALSE);
5538 if (chunking_state > CHUNKING_OFFERED)
5540 bdat_push_receive_functions();
5546 if (chunking_state > CHUNKING_OFFERED)
5547 rc = OK; /* No predata ACL or go-ahead output for BDAT */
5550 /* If there is an ACL, re-check the synchronization afterwards, since the
5551 ACL may have delayed. To handle cutthrough delivery enforce a dummy call
5552 to get the DATA command sent. */
5554 if (!acl_smtp_predata && cutthrough.cctx.sock < 0)
5558 uschar * acl = acl_smtp_predata ? acl_smtp_predata : US"accept";
5559 f.enable_dollar_recipients = TRUE;
5560 rc = acl_check(ACL_WHERE_PREDATA, NULL, acl, &user_msg,
5562 f.enable_dollar_recipients = FALSE;
5563 if (rc == OK && !check_sync())
5567 { /* Either the ACL failed the address, or it was deferred. */
5568 done = smtp_handle_acl_fail(ACL_WHERE_PREDATA, rc, user_msg, log_msg);
5574 smtp_user_msg(US"354", user_msg);
5577 "354 Enter message, ending with \".\" on a line by itself\r\n", FALSE);
5580 if (f.bdat_readers_wanted)
5581 bdat_push_receive_functions();
5584 if (smtp_in) /* all ACKs needed to ramp window up for bulk data */
5585 (void) setsockopt(fileno(smtp_in), IPPROTO_TCP, TCP_QUICKACK,
5586 US &on, sizeof(on));
5589 message_ended = END_NOTENDED; /* Indicate in middle of data */
5600 if (!(address = parse_extract_address(smtp_cmd_data, &errmess,
5601 &start, &end, &recipient_domain, FALSE)))
5603 smtp_printf("501 %s\r\n", FALSE, errmess);
5607 if (!recipient_domain)
5608 if (!(recipient_domain = qualify_recipient(&address, smtp_cmd_data,
5612 if ((rc = acl_check(ACL_WHERE_VRFY, address, acl_smtp_vrfy,
5613 &user_msg, &log_msg)) != OK)
5614 done = smtp_handle_acl_fail(ACL_WHERE_VRFY, rc, user_msg, log_msg);
5618 address_item * addr = deliver_make_addr(address, FALSE);
5620 switch(verify_address(addr, NULL, vopt_is_recipient | vopt_qualify, -1,
5621 -1, -1, NULL, NULL, NULL))
5624 s = string_sprintf("250 <%s> is deliverable", address);
5628 s = (addr->user_message != NULL)?
5629 string_sprintf("451 <%s> %s", address, addr->user_message) :
5630 string_sprintf("451 Cannot resolve <%s> at this time", address);
5634 s = (addr->user_message != NULL)?
5635 string_sprintf("550 <%s> %s", address, addr->user_message) :
5636 string_sprintf("550 <%s> is not deliverable", address);
5637 log_write(0, LOG_MAIN, "VRFY failed for %s %s",
5638 smtp_cmd_argument, host_and_ident(TRUE));
5642 smtp_printf("%s\r\n", FALSE, s);
5650 rc = acl_check(ACL_WHERE_EXPN, NULL, acl_smtp_expn, &user_msg, &log_msg);
5652 done = smtp_handle_acl_fail(ACL_WHERE_EXPN, rc, user_msg, log_msg);
5655 BOOL save_log_testing_mode = f.log_testing_mode;
5656 f.address_test_mode = f.log_testing_mode = TRUE;
5657 (void) verify_address(deliver_make_addr(smtp_cmd_data, FALSE),
5658 smtp_out, vopt_is_recipient | vopt_qualify | vopt_expn, -1, -1, -1,
5660 f.address_test_mode = FALSE;
5661 f.log_testing_mode = save_log_testing_mode; /* true for -bh */
5670 if (!fl.tls_advertised)
5672 done = synprot_error(L_smtp_protocol_error, 503, NULL,
5673 US"STARTTLS command used when not advertised");
5677 /* Apply an ACL check if one is defined */
5679 if ( acl_smtp_starttls
5680 && (rc = acl_check(ACL_WHERE_STARTTLS, NULL, acl_smtp_starttls,
5681 &user_msg, &log_msg)) != OK
5684 done = smtp_handle_acl_fail(ACL_WHERE_STARTTLS, rc, user_msg, log_msg);
5688 /* RFC 2487 is not clear on when this command may be sent, though it
5689 does state that all information previously obtained from the client
5690 must be discarded if a TLS session is started. It seems reasonable to
5691 do an implied RSET when STARTTLS is received. */
5693 incomplete_transaction_log(US"STARTTLS");
5694 cancel_cutthrough_connection(TRUE, US"STARTTLS received");
5695 reset_point = smtp_reset(reset_point);
5697 cmd_list[CL_STLS].is_mail_cmd = FALSE;
5699 /* There's an attack where more data is read in past the STARTTLS command
5700 before TLS is negotiated, then assumed to be part of the secure session
5701 when used afterwards; we use segregated input buffers, so are not
5702 vulnerable, but we want to note when it happens and, for sheer paranoia,
5703 ensure that the buffer is "wiped".
5704 Pipelining sync checks will normally have protected us too, unless disabled
5705 by configuration. */
5710 debug_printf("Non-empty input buffer after STARTTLS; naive attack?\n");
5711 if (tls_in.active.sock < 0)
5712 smtp_inend = smtp_inptr = smtp_inbuffer;
5713 /* and if TLS is already active, tls_server_start() should fail */
5716 /* There is nothing we value in the input buffer and if TLS is successfully
5717 negotiated, we won't use this buffer again; if TLS fails, we'll just read
5718 fresh content into it. The buffer contains arbitrary content from an
5719 untrusted remote source; eg: NOOP <shellcode>\r\nSTARTTLS\r\n
5720 It seems safest to just wipe away the content rather than leave it as a
5721 target to jump to. */
5723 memset(smtp_inbuffer, 0, IN_BUFFER_SIZE);
5725 /* Attempt to start up a TLS session, and if successful, discard all
5726 knowledge that was obtained previously. At least, that's what the RFC says,
5727 and that's what happens by default. However, in order to work round YAEB,
5728 there is an option to remember the esmtp state. Sigh.
5730 We must allow for an extra EHLO command and an extra AUTH command after
5731 STARTTLS that don't add to the nonmail command count. */
5734 if ((rc = tls_server_start(&s)) == OK)
5736 if (!tls_remember_esmtp)
5737 fl.helo_seen = fl.esmtp = fl.auth_advertised = f.smtp_in_pipelining_advertised = FALSE;
5738 cmd_list[CL_EHLO].is_mail_cmd = TRUE;
5739 cmd_list[CL_AUTH].is_mail_cmd = TRUE;
5740 cmd_list[CL_TLAU].is_mail_cmd = TRUE;
5741 if (sender_helo_name)
5743 sender_helo_name = NULL;
5744 host_build_sender_fullhost(); /* Rebuild */
5745 set_process_info("handling incoming TLS connection from %s",
5746 host_and_ident(FALSE));
5749 (sender_host_address ? protocols : protocols_local)
5751 ? pextend + (sender_host_authenticated ? pauthed : 0)
5753 + (tls_in.active.sock >= 0 ? pcrpted : 0)
5756 sender_host_auth_pubname = sender_host_authenticated = NULL;
5757 authenticated_id = NULL;
5758 sync_cmd_limit = NON_SYNC_CMD_NON_PIPELINING;
5759 DEBUG(D_tls) debug_printf("TLS active\n");
5760 break; /* Successful STARTTLS */
5763 (void) smtp_log_tls_fail(s);
5765 /* Some local configuration problem was discovered before actually trying
5766 to do a TLS handshake; give a temporary error. */
5770 smtp_printf("454 TLS currently unavailable\r\n", FALSE);
5774 /* Hard failure. Reject everything except QUIT or closed connection. One
5775 cause for failure is a nested STARTTLS, in which case tls_in.active remains
5776 set, but we must still reject all incoming commands. Another is a handshake
5777 failure - and there may some encrypted data still in the pipe to us, which we
5778 see as garbage commands. */
5780 DEBUG(D_tls) debug_printf("TLS failed to start\n");
5781 while (done <= 0) switch(smtp_read_command(FALSE, GETC_BUFFER_UNLIMITED))
5784 log_close_event(US"by EOF");
5785 smtp_notquit_exit(US"tls-failed", NULL, NULL);
5789 /* It is perhaps arguable as to which exit ACL should be called here,
5790 but as it is probably a situation that almost never arises, it
5791 probably doesn't matter. We choose to call the real QUIT ACL, which in
5792 some sense is perhaps "right". */
5795 f.smtp_in_quit = TRUE;
5798 && ((rc = acl_check(ACL_WHERE_QUIT, NULL, acl_smtp_quit, &user_msg,
5799 &log_msg)) == ERROR))
5800 log_write(0, LOG_MAIN|LOG_PANIC, "ACL for QUIT returned ERROR: %s",
5803 smtp_respond(US"221", 3, TRUE, user_msg);
5805 smtp_printf("221 %s closing connection\r\n", FALSE, smtp_active_hostname);
5806 log_close_event(US"by QUIT");
5811 smtp_printf("554 Security failure\r\n", FALSE);
5814 tls_close(NULL, TLS_SHUTDOWN_NOWAIT);
5819 /* The ACL for QUIT is provided for gathering statistical information or
5820 similar; it does not affect the response code, but it can supply a custom
5824 smtp_quit_handler(&user_msg, &log_msg);
5830 smtp_rset_handler();
5831 cancel_cutthrough_connection(TRUE, US"RSET received");
5832 reset_point = smtp_reset(reset_point);
5839 smtp_printf("250 OK\r\n", FALSE);
5843 /* Show ETRN/EXPN/VRFY if there's an ACL for checking hosts; if actually
5844 used, a check will be done for permitted hosts. Show STARTTLS only if not
5845 already in a TLS session and if it would be advertised in the EHLO
5850 smtp_printf("214-Commands supported:\r\n214", TRUE);
5851 smtp_printf(" AUTH", TRUE);
5853 if (tls_in.active.sock < 0 &&
5854 verify_check_host(&tls_advertise_hosts) != FAIL)
5855 smtp_printf(" STARTTLS", TRUE);
5857 smtp_printf(" HELO EHLO MAIL RCPT DATA BDAT", TRUE);
5858 smtp_printf(" NOOP QUIT RSET HELP", TRUE);
5859 if (acl_smtp_etrn) smtp_printf(" ETRN", TRUE);
5860 if (acl_smtp_expn) smtp_printf(" EXPN", TRUE);
5861 if (acl_smtp_vrfy) smtp_printf(" VRFY", TRUE);
5862 smtp_printf("\r\n", FALSE);
5867 incomplete_transaction_log(US"connection lost");
5868 smtp_notquit_exit(US"connection-lost", US"421",
5869 US"%s lost input connection", smtp_active_hostname);
5871 /* Don't log by default unless in the middle of a message, as some mailers
5872 just drop the call rather than sending QUIT, and it clutters up the logs.
5875 if (sender_address || recipients_count > 0)
5876 log_write(L_lost_incoming_connection, LOG_MAIN,
5877 "unexpected %s while reading SMTP command from %s%s%s D=%s",
5878 f.sender_host_unknown ? "EOF" : "disconnection",
5879 f.tcp_in_fastopen_logged
5882 ? f.tcp_in_fastopen_data ? US"TFO* " : US"TFO "
5884 host_and_ident(FALSE), smtp_read_error,
5885 string_timesince(&smtp_connection_start)
5889 log_write(L_smtp_connection, LOG_MAIN, "%s %slost%s D=%s",
5890 smtp_get_connection_info(),
5891 f.tcp_in_fastopen && !f.tcp_in_fastopen_logged ? US"TFO " : US"",
5893 string_timesince(&smtp_connection_start)
5904 done = synprot_error(L_smtp_protocol_error, 503, NULL,
5905 US"ETRN is not permitted inside a transaction");
5909 log_write(L_etrn, LOG_MAIN, "ETRN %s received from %s", smtp_cmd_argument,
5910 host_and_ident(FALSE));
5912 if ((rc = acl_check(ACL_WHERE_ETRN, NULL, acl_smtp_etrn,
5913 &user_msg, &log_msg)) != OK)
5915 done = smtp_handle_acl_fail(ACL_WHERE_ETRN, rc, user_msg, log_msg);
5919 /* Compute the serialization key for this command. */
5921 etrn_serialize_key = string_sprintf("etrn-%s\n", smtp_cmd_data);
5923 /* If a command has been specified for running as a result of ETRN, we
5924 permit any argument to ETRN. If not, only the # standard form is permitted,
5925 since that is strictly the only kind of ETRN that can be implemented
5926 according to the RFC. */
5928 if (smtp_etrn_command)
5932 etrn_command = smtp_etrn_command;
5933 deliver_domain = smtp_cmd_data;
5934 rc = transport_set_up_command(&argv, smtp_etrn_command, TRUE, 0, NULL,
5935 FALSE, US"ETRN processing", &error);
5936 deliver_domain = NULL;
5939 log_write(0, LOG_MAIN|LOG_PANIC, "failed to set up ETRN command: %s",
5941 smtp_printf("458 Internal failure\r\n", FALSE);
5946 /* Else set up to call Exim with the -R option. */
5950 if (*smtp_cmd_data++ != '#')
5952 done = synprot_error(L_smtp_syntax_error, 501, NULL,
5953 US"argument must begin with #");
5956 etrn_command = US"exim -R";
5957 argv = CUSS child_exec_exim(CEE_RETURN_ARGV, TRUE, NULL, TRUE,
5958 *queue_name ? 4 : 2,
5959 US"-R", smtp_cmd_data,
5960 US"-MCG", queue_name);
5963 /* If we are host-testing, don't actually do anything. */
5969 debug_printf("ETRN command is: %s\n", etrn_command);
5970 debug_printf("ETRN command execution skipped\n");
5972 if (user_msg == NULL) smtp_printf("250 OK\r\n", FALSE);
5973 else smtp_user_msg(US"250", user_msg);
5978 /* If ETRN queue runs are to be serialized, check the database to
5979 ensure one isn't already running. */
5981 if (smtp_etrn_serialize && !enq_start(etrn_serialize_key, 1))
5983 smtp_printf("458 Already processing %s\r\n", FALSE, smtp_cmd_data);
5987 /* Fork a child process and run the command. We don't want to have to
5988 wait for the process at any point, so set SIGCHLD to SIG_IGN before
5989 forking. It should be set that way anyway for external incoming SMTP,
5990 but we save and restore to be tidy. If serialization is required, we
5991 actually run the command in yet another process, so we can wait for it
5992 to complete and then remove the serialization lock. */
5994 oldsignal = signal(SIGCHLD, SIG_IGN);
5996 if ((pid = exim_fork(US"etrn-command")) == 0)
5998 smtp_input = FALSE; /* This process is not associated with the */
5999 (void)fclose(smtp_in); /* SMTP call any more. */
6000 (void)fclose(smtp_out);
6002 signal(SIGCHLD, SIG_DFL); /* Want to catch child */
6004 /* If not serializing, do the exec right away. Otherwise, fork down
6005 into another process. */
6007 if ( !smtp_etrn_serialize
6008 || (pid = exim_fork(US"etrn-serialised-command")) == 0)
6010 DEBUG(D_exec) debug_print_argv(argv);
6011 exim_nullstd(); /* Ensure std{in,out,err} exist */
6012 /* argv[0] should be untainted, from child_exec_exim() */
6013 execv(CS argv[0], (char *const *)argv);
6014 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "exec of \"%s\" (ETRN) failed: %s",
6015 etrn_command, strerror(errno));
6016 _exit(EXIT_FAILURE); /* paranoia */
6019 /* Obey this if smtp_serialize and the 2nd fork yielded non-zero. That
6020 is, we are in the first subprocess, after forking again. All we can do
6021 for a failing fork is to log it. Otherwise, wait for the 2nd process to
6022 complete, before removing the serialization. */
6025 log_write(0, LOG_MAIN|LOG_PANIC, "2nd fork for serialized ETRN "
6026 "failed: %s", strerror(errno));
6030 DEBUG(D_any) debug_printf("waiting for serialized ETRN process %d\n",
6032 (void)wait(&status);
6033 DEBUG(D_any) debug_printf("serialized ETRN process %d ended\n",
6037 enq_end(etrn_serialize_key);
6038 exim_underbar_exit(EXIT_SUCCESS);
6041 /* Back in the top level SMTP process. Check that we started a subprocess
6042 and restore the signal state. */
6046 log_write(0, LOG_MAIN|LOG_PANIC, "fork of process for ETRN failed: %s",
6048 smtp_printf("458 Unable to fork process\r\n", FALSE);
6049 if (smtp_etrn_serialize) enq_end(etrn_serialize_key);
6053 smtp_printf("250 OK\r\n", FALSE);
6055 smtp_user_msg(US"250", user_msg);
6057 signal(SIGCHLD, oldsignal);
6062 done = synprot_error(L_smtp_syntax_error, 501, NULL,
6063 US"unexpected argument data");
6067 /* This currently happens only for NULLs, but could be extended. */
6070 done = synprot_error(L_smtp_syntax_error, 0, NULL, /* Just logs */
6071 US"NUL character(s) present (shown as '?')");
6072 smtp_printf("501 NUL characters are not allowed in SMTP commands\r\n",
6079 if (smtp_inend >= smtp_inbuffer + IN_BUFFER_SIZE)
6080 smtp_inend = smtp_inbuffer + IN_BUFFER_SIZE - 1;
6081 c = smtp_inend - smtp_inptr;
6082 if (c > 150) c = 150; /* limit logged amount */
6084 incomplete_transaction_log(US"sync failure");
6085 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP protocol synchronization error "
6086 "(next input sent too soon: pipelining was%s advertised): "
6087 "rejected \"%s\" %s next input=\"%s\"",
6088 f.smtp_in_pipelining_advertised ? "" : " not",
6089 smtp_cmd_buffer, host_and_ident(TRUE),
6090 string_printing(smtp_inptr));
6091 smtp_notquit_exit(US"synchronization-error", US"554",
6092 US"SMTP synchronization error");
6093 done = 1; /* Pretend eof - drops connection */
6097 case TOO_MANY_NONMAIL_CMD:
6098 s = smtp_cmd_buffer;
6099 while (*s != 0 && !isspace(*s)) s++;
6100 incomplete_transaction_log(US"too many non-mail commands");
6101 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
6102 "nonmail commands (last was \"%.*s\")", host_and_ident(FALSE),
6103 (int)(s - smtp_cmd_buffer), smtp_cmd_buffer);
6104 smtp_notquit_exit(US"bad-commands", US"554", US"Too many nonmail commands");
6105 done = 1; /* Pretend eof - drops connection */
6108 #ifdef SUPPORT_PROXY
6109 case PROXY_FAIL_IGNORE_CMD:
6110 smtp_printf("503 Command refused, required Proxy negotiation failed\r\n", FALSE);
6115 if (unknown_command_count++ >= smtp_max_unknown_commands)
6117 log_write(L_smtp_syntax_error, LOG_MAIN,
6118 "SMTP syntax error in \"%s\" %s %s",
6119 string_printing(smtp_cmd_buffer), host_and_ident(TRUE),
6120 US"unrecognized command");
6121 incomplete_transaction_log(US"unrecognized command");
6122 smtp_notquit_exit(US"bad-commands", US"500",
6123 US"Too many unrecognized commands");
6125 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
6126 "unrecognized commands (last was \"%s\")", host_and_ident(FALSE),
6127 string_printing(smtp_cmd_buffer));
6130 done = synprot_error(L_smtp_syntax_error, 500, NULL,
6131 US"unrecognized command");
6135 /* This label is used by goto's inside loops that want to break out to
6136 the end of the command-processing loop. */
6139 last_was_rej_mail = was_rej_mail; /* Remember some last commands for */
6140 last_was_rcpt = was_rcpt; /* protocol error handling */
6143 return done - 2; /* Convert yield values */
6149 authres_smtpauth(gstring * g)
6151 if (!sender_host_authenticated)
6154 g = string_append(g, 2, US";\n\tauth=pass (", sender_host_auth_pubname);
6156 if (Ustrcmp(sender_host_auth_pubname, "tls") == 0)
6157 g = authenticated_id
6158 ? string_append(g, 2, US") x509.auth=", authenticated_id)
6159 : string_cat(g, US") reason=x509.auth");
6161 g = authenticated_id
6162 ? string_append(g, 2, US") smtp.auth=", authenticated_id)
6163 : string_cat(g, US", no id saved)");
6165 if (authenticated_sender)
6166 g = string_append(g, 2, US" smtp.mailfrom=", authenticated_sender);
6174 /* End of smtp_in.c */