1 /*************************************************
2 * Exim - an Internet mail transport agent *
3 *************************************************/
5 /* Copyright (c) University of Cambridge 1995 - 2018 */
6 /* See the file NOTICE for conditions of use and distribution. */
8 /* Functions for handling an incoming SMTP call. */
15 /* Initialize for TCP wrappers if so configured. It appears that the macro
16 HAVE_IPV6 is used in some versions of the tcpd.h header, so we unset it before
17 including that header, and restore its value afterwards. */
19 #ifdef USE_TCP_WRAPPERS
22 #define EXIM_HAVE_IPV6
28 #define HAVE_IPV6 TRUE
31 int allow_severity = LOG_INFO;
32 int deny_severity = LOG_NOTICE;
33 uschar *tcp_wrappers_name;
37 /* Size of buffer for reading SMTP commands. We used to use 512, as defined
38 by RFC 821. However, RFC 1869 specifies that this must be increased for SMTP
39 commands that accept arguments, and this in particular applies to AUTH, where
40 the data can be quite long. More recently this value was 2048 in Exim;
41 however, RFC 4954 (circa 2007) recommends 12288 bytes to handle AUTH. Clients
42 such as Thunderbird will send an AUTH with an initial-response for GSSAPI.
43 The maximum size of a Kerberos ticket under Windows 2003 is 12000 bytes, and
44 we need room to handle large base64-encoded AUTHs for GSSAPI.
47 #define SMTP_CMD_BUFFER_SIZE 16384
49 /* Size of buffer for reading SMTP incoming packets */
51 #define IN_BUFFER_SIZE 8192
53 /* Structure for SMTP command list */
60 short int is_mail_cmd;
63 /* Codes for identifying commands. We order them so that those that come first
64 are those for which synchronization is always required. Checking this can help
68 /* These commands are required to be synchronized, i.e. to be the last in a
69 block of commands when pipelining. */
71 HELO_CMD, EHLO_CMD, DATA_CMD, /* These are listed in the pipelining */
72 VRFY_CMD, EXPN_CMD, NOOP_CMD, /* RFC as requiring synchronization */
73 ETRN_CMD, /* This by analogy with TURN from the RFC */
74 STARTTLS_CMD, /* Required by the STARTTLS RFC */
75 TLS_AUTH_CMD, /* auto-command at start of SSL */
77 /* This is a dummy to identify the non-sync commands when pipelining */
79 NON_SYNC_CMD_PIPELINING,
81 /* These commands need not be synchronized when pipelining */
83 MAIL_CMD, RCPT_CMD, RSET_CMD,
85 /* This is a dummy to identify the non-sync commands when not pipelining */
87 NON_SYNC_CMD_NON_PIPELINING,
89 /* RFC3030 section 2: "After all MAIL and RCPT responses are collected and
90 processed the message is sent using a series of BDAT commands"
91 implies that BDAT should be synchronized. However, we see Google, at least,
92 sending MAIL,RCPT,BDAT-LAST in a single packet, clearly not waiting for
93 processing of the RCPT response(s). We shall do the same, and not require
94 synch for BDAT. Worse, as the chunk may (very likely will) follow the
95 command-header in the same packet we cannot do the usual "is there any
96 follow-on data after the command line" even for non-pipeline mode.
97 So we'll need an explicit check after reading the expected chunk amount
98 when non-pipe, before sending the ACK. */
102 /* I have been unable to find a statement about the use of pipelining
103 with AUTH, so to be on the safe side it is here, though I kind of feel
104 it should be up there with the synchronized commands. */
108 /* I'm not sure about these, but I don't think they matter. */
113 PROXY_FAIL_IGNORE_CMD,
116 /* These are specials that don't correspond to actual commands */
118 EOF_CMD, OTHER_CMD, BADARG_CMD, BADCHAR_CMD, BADSYN_CMD,
119 TOO_MANY_NONMAIL_CMD };
122 /* This is a convenience macro for adding the identity of an SMTP command
123 to the circular buffer that holds a list of the last n received. */
126 smtp_connection_had[smtp_ch_index++] = n; \
127 if (smtp_ch_index >= SMTP_HBUFF_SIZE) smtp_ch_index = 0
130 /*************************************************
131 * Local static variables *
132 *************************************************/
134 static auth_instance *authenticated_by;
135 static BOOL auth_advertised;
137 static BOOL tls_advertised;
139 static BOOL dsn_advertised;
141 static BOOL helo_required = FALSE;
142 static BOOL helo_verify = FALSE;
143 static BOOL helo_seen;
144 static BOOL helo_accept_junk;
145 static BOOL count_nonmail;
146 static BOOL pipelining_advertised;
147 static BOOL rcpt_smtp_response_same;
148 static BOOL rcpt_in_progress;
149 static int nonmail_command_count;
150 static BOOL smtp_exit_function_called = 0;
152 static BOOL smtputf8_advertised;
154 static int synprot_error_count;
155 static int unknown_command_count;
156 static int sync_cmd_limit;
157 static int smtp_write_error = 0;
159 static uschar *rcpt_smtp_response;
160 static uschar *smtp_data_buffer;
161 static uschar *smtp_cmd_data;
163 /* We need to know the position of RSET, HELO, EHLO, AUTH, and STARTTLS. Their
164 final fields of all except AUTH are forced TRUE at the start of a new message
165 setup, to allow one of each between messages that is not counted as a nonmail
166 command. (In fact, only one of HELO/EHLO is not counted.) Also, we have to
167 allow a new EHLO after starting up TLS.
169 AUTH is "falsely" labelled as a mail command initially, so that it doesn't get
170 counted. However, the flag is changed when AUTH is received, so that multiple
171 failing AUTHs will eventually hit the limit. After a successful AUTH, another
172 AUTH is already forbidden. After a TLS session is started, AUTH's flag is again
173 forced TRUE, to allow for the re-authentication that can happen at that point.
175 QUIT is also "falsely" labelled as a mail command so that it doesn't up the
176 count of non-mail commands and possibly provoke an error.
178 tls_auth is a pseudo-command, never expected in input. It is activated
179 on TLS startup and looks for a tls authenticator. */
181 static smtp_cmd_list cmd_list[] = {
182 /* name len cmd has_arg is_mail_cmd */
184 { "rset", sizeof("rset")-1, RSET_CMD, FALSE, FALSE }, /* First */
185 { "helo", sizeof("helo")-1, HELO_CMD, TRUE, FALSE },
186 { "ehlo", sizeof("ehlo")-1, EHLO_CMD, TRUE, FALSE },
187 { "auth", sizeof("auth")-1, AUTH_CMD, TRUE, TRUE },
189 { "starttls", sizeof("starttls")-1, STARTTLS_CMD, FALSE, FALSE },
190 { "tls_auth", 0, TLS_AUTH_CMD, FALSE, FALSE },
193 /* If you change anything above here, also fix the definitions below. */
195 { "mail from:", sizeof("mail from:")-1, MAIL_CMD, TRUE, TRUE },
196 { "rcpt to:", sizeof("rcpt to:")-1, RCPT_CMD, TRUE, TRUE },
197 { "data", sizeof("data")-1, DATA_CMD, FALSE, TRUE },
198 { "bdat", sizeof("bdat")-1, BDAT_CMD, TRUE, TRUE },
199 { "quit", sizeof("quit")-1, QUIT_CMD, FALSE, TRUE },
200 { "noop", sizeof("noop")-1, NOOP_CMD, TRUE, FALSE },
201 { "etrn", sizeof("etrn")-1, ETRN_CMD, TRUE, FALSE },
202 { "vrfy", sizeof("vrfy")-1, VRFY_CMD, TRUE, FALSE },
203 { "expn", sizeof("expn")-1, EXPN_CMD, TRUE, FALSE },
204 { "help", sizeof("help")-1, HELP_CMD, TRUE, FALSE }
207 static smtp_cmd_list *cmd_list_end =
208 cmd_list + sizeof(cmd_list)/sizeof(smtp_cmd_list);
210 #define CMD_LIST_RSET 0
211 #define CMD_LIST_HELO 1
212 #define CMD_LIST_EHLO 2
213 #define CMD_LIST_AUTH 3
214 #define CMD_LIST_STARTTLS 4
215 #define CMD_LIST_TLS_AUTH 5
217 /* This list of names is used for performing the smtp_no_mail logging action.
218 It must be kept in step with the SCH_xxx enumerations. */
220 static uschar *smtp_names[] =
222 US"NONE", US"AUTH", US"DATA", US"BDAT", US"EHLO", US"ETRN", US"EXPN",
223 US"HELO", US"HELP", US"MAIL", US"NOOP", US"QUIT", US"RCPT", US"RSET",
224 US"STARTTLS", US"VRFY" };
226 static uschar *protocols_local[] = {
227 US"local-smtp", /* HELO */
228 US"local-smtps", /* The rare case EHLO->STARTTLS->HELO */
229 US"local-esmtp", /* EHLO */
230 US"local-esmtps", /* EHLO->STARTTLS->EHLO */
231 US"local-esmtpa", /* EHLO->AUTH */
232 US"local-esmtpsa" /* EHLO->STARTTLS->EHLO->AUTH */
234 static uschar *protocols[] = {
236 US"smtps", /* The rare case EHLO->STARTTLS->HELO */
237 US"esmtp", /* EHLO */
238 US"esmtps", /* EHLO->STARTTLS->EHLO */
239 US"esmtpa", /* EHLO->AUTH */
240 US"esmtpsa" /* EHLO->STARTTLS->EHLO->AUTH */
245 #define pcrpted 1 /* added to pextend or pnormal */
246 #define pauthed 2 /* added to pextend */
248 /* Sanity check and validate optional args to MAIL FROM: envelope */
251 ENV_MAIL_OPT_SIZE, ENV_MAIL_OPT_BODY, ENV_MAIL_OPT_AUTH,
255 ENV_MAIL_OPT_RET, ENV_MAIL_OPT_ENVID,
261 uschar * name; /* option requested during MAIL cmd */
262 int value; /* enum type */
263 BOOL need_value; /* TRUE requires value (name=value pair format)
264 FALSE is a singleton */
266 static env_mail_type_t env_mail_type_list[] = {
267 { US"SIZE", ENV_MAIL_OPT_SIZE, TRUE },
268 { US"BODY", ENV_MAIL_OPT_BODY, TRUE },
269 { US"AUTH", ENV_MAIL_OPT_AUTH, TRUE },
271 { US"PRDR", ENV_MAIL_OPT_PRDR, FALSE },
273 { US"RET", ENV_MAIL_OPT_RET, TRUE },
274 { US"ENVID", ENV_MAIL_OPT_ENVID, TRUE },
276 { US"SMTPUTF8",ENV_MAIL_OPT_UTF8, FALSE }, /* rfc6531 */
278 /* keep this the last entry */
279 { US"NULL", ENV_MAIL_OPT_NULL, FALSE },
282 /* When reading SMTP from a remote host, we have to use our own versions of the
283 C input-reading functions, in order to be able to flush the SMTP output only
284 when about to read more data from the socket. This is the only way to get
285 optimal performance when the client is using pipelining. Flushing for every
286 command causes a separate packet and reply packet each time; saving all the
287 responses up (when pipelining) combines them into one packet and one response.
289 For simplicity, these functions are used for *all* SMTP input, not only when
290 receiving over a socket. However, after setting up a secure socket (SSL), input
291 is read via the OpenSSL library, and another set of functions is used instead
294 These functions are set in the receive_getc etc. variables and called with the
295 same interface as the C functions. However, since there can only ever be
296 one incoming SMTP call, we just use a single buffer and flags. There is no need
297 to implement a complicated private FILE-like structure.*/
299 static uschar *smtp_inbuffer;
300 static uschar *smtp_inptr;
301 static uschar *smtp_inend;
302 static int smtp_had_eof;
303 static int smtp_had_error;
306 /* forward declarations */
307 static int smtp_read_command(BOOL check_sync, unsigned buffer_lim);
308 static int synprot_error(int type, int code, uschar *data, uschar *errmess);
309 static void smtp_quit_handler(uschar **, uschar **);
310 static void smtp_rset_handler(void);
312 /*************************************************
313 * Recheck synchronization *
314 *************************************************/
316 /* Synchronization checks can never be perfect because a packet may be on its
317 way but not arrived when the check is done. Normally, the checks happen when
318 commands are read: Exim ensures that there is no more input in the input buffer.
319 In normal cases, the response to the command will be fast, and there is no
322 However, for some commands an ACL is run, and that can include delays. In those
323 cases, it is useful to do another check on the input just before sending the
324 response. This also applies at the start of a connection. This function does
325 that check by means of the select() function, as long as the facility is not
326 disabled or inappropriate. A failure of select() is ignored.
328 When there is unwanted input, we read it so that it appears in the log of the
332 Returns: TRUE if all is well; FALSE if there is input pending
336 wouldblock_reading(void)
340 struct timeval tzero;
343 if (tls_in.active >= 0)
344 return !tls_could_read();
347 if (smtp_inptr < smtp_inend)
350 fd = fileno(smtp_in);
355 rc = select(fd + 1, (SELECT_ARG2_TYPE *)&fds, NULL, NULL, &tzero);
357 if (rc <= 0) return TRUE; /* Not ready to read */
358 rc = smtp_getc(GETC_BUFFER_UNLIMITED);
359 if (rc < 0) return TRUE; /* End of file or error */
368 if (!smtp_enforce_sync || !sender_host_address || sender_host_notsocket)
371 return wouldblock_reading();
375 /* If there's input waiting (and we're doing pipelineing) then we can pipeline
376 a reponse with the one following. */
379 pipeline_response(void)
381 if ( !smtp_enforce_sync || !sender_host_address
382 || sender_host_notsocket || !pipelining_advertised)
385 return !wouldblock_reading();
390 /*************************************************
391 * Log incomplete transactions *
392 *************************************************/
394 /* This function is called after a transaction has been aborted by RSET, QUIT,
395 connection drops or other errors. It logs the envelope information received
396 so far in order to preserve address verification attempts.
398 Argument: string to indicate what aborted the transaction
403 incomplete_transaction_log(uschar *what)
405 if (sender_address == NULL || /* No transaction in progress */
406 !LOGGING(smtp_incomplete_transaction))
409 /* Build list of recipients for logging */
411 if (recipients_count > 0)
414 raw_recipients = store_get(recipients_count * sizeof(uschar *));
415 for (i = 0; i < recipients_count; i++)
416 raw_recipients[i] = recipients_list[i].address;
417 raw_recipients_count = recipients_count;
420 log_write(L_smtp_incomplete_transaction, LOG_MAIN|LOG_SENDER|LOG_RECIPIENTS,
421 "%s incomplete transaction (%s)", host_and_ident(TRUE), what);
428 smtp_command_timeout_exit(void)
430 log_write(L_lost_incoming_connection,
431 LOG_MAIN, "SMTP command timeout on%s connection from %s",
432 tls_in.active >= 0 ? " TLS" : "", host_and_ident(FALSE));
433 if (smtp_batched_input)
434 moan_smtp_batch(NULL, "421 SMTP command timeout"); /* Does not return */
435 smtp_notquit_exit(US"command-timeout", US"421",
436 US"%s: SMTP command timeout - closing connection",
437 smtp_active_hostname);
438 exim_exit(EXIT_FAILURE, US"receiving");
442 smtp_command_sigterm_exit(void)
444 log_write(0, LOG_MAIN, "%s closed after SIGTERM", smtp_get_connection_info());
445 if (smtp_batched_input)
446 moan_smtp_batch(NULL, "421 SIGTERM received"); /* Does not return */
447 smtp_notquit_exit(US"signal-exit", US"421",
448 US"%s: Service not available - closing connection", smtp_active_hostname);
449 exim_exit(EXIT_FAILURE, US"receiving");
453 smtp_data_timeout_exit(void)
455 log_write(L_lost_incoming_connection,
456 LOG_MAIN, "SMTP data timeout (message abandoned) on connection from %s F=<%s>",
457 sender_fullhost ? sender_fullhost : US"local process", sender_address);
458 receive_bomb_out(US"data-timeout", US"SMTP incoming data timeout");
459 /* Does not return */
463 smtp_data_sigint_exit(void)
465 log_write(0, LOG_MAIN, "%s closed after %s",
466 smtp_get_connection_info(), had_data_sigint == SIGTERM ? "SIGTERM":"SIGINT");
467 receive_bomb_out(US"signal-exit",
468 US"Service not available - SIGTERM or SIGINT received");
469 /* Does not return */
474 /* Refill the buffer, and notify DKIM verification code.
475 Return false for error or EOF.
479 smtp_refill(unsigned lim)
482 if (!smtp_out) return FALSE;
484 if (smtp_receive_timeout > 0) alarm(smtp_receive_timeout);
486 /* Limit amount read, so non-message data is not fed to DKIM.
487 Take care to not touch the safety NUL at the end of the buffer. */
489 rc = read(fileno(smtp_in), smtp_inbuffer, MIN(IN_BUFFER_SIZE-1, lim));
491 if (smtp_receive_timeout > 0) alarm(0);
494 /* Must put the error text in fixed store, because this might be during
495 header reading, where it releases unused store above the header. */
498 if (had_command_timeout) /* set by signal handler */
499 smtp_command_timeout_exit(); /* does not return */
500 if (had_command_sigterm)
501 smtp_command_sigterm_exit();
502 if (had_data_timeout)
503 smtp_data_timeout_exit();
505 smtp_data_sigint_exit();
507 smtp_had_error = save_errno;
508 smtp_read_error = string_copy_malloc(
509 string_sprintf(" (error: %s)", strerror(save_errno)));
516 dkim_exim_verify_feed(smtp_inbuffer, rc);
518 smtp_inend = smtp_inbuffer + rc;
519 smtp_inptr = smtp_inbuffer;
523 /*************************************************
524 * SMTP version of getc() *
525 *************************************************/
527 /* This gets the next byte from the SMTP input buffer. If the buffer is empty,
528 it flushes the output, and refills the buffer, with a timeout. The signal
529 handler is set appropriately by the calling function. This function is not used
530 after a connection has negotiated itself into an TLS/SSL state.
532 Arguments: lim Maximum amount to read/buffer
533 Returns: the next character or EOF
537 smtp_getc(unsigned lim)
539 if (smtp_inptr >= smtp_inend)
540 if (!smtp_refill(lim))
542 return *smtp_inptr++;
546 smtp_getbuf(unsigned * len)
551 if (smtp_inptr >= smtp_inend)
552 if (!smtp_refill(*len))
553 { *len = 0; return NULL; }
555 if ((size = smtp_inend - smtp_inptr) > *len) size = *len;
566 int n = smtp_inend - smtp_inptr;
568 dkim_exim_verify_feed(smtp_inptr, n);
573 /* Get a byte from the smtp input, in CHUNKING mode. Handle ack of the
574 previous BDAT chunk and getting new ones when we run out. Uses the
575 underlying smtp_getc or tls_getc both for that and for getting the
576 (buffered) data byte. EOD signals (an expected) no further data.
577 ERR signals a protocol error, and EOF a closed input stream.
579 Called from read_bdat_smtp() in receive.c for the message body, but also
580 by the headers read loop in receive_msg(); manipulates chunking_state
581 to handle the BDAT command/response.
582 Placed here due to the correlation with the above smtp_getc(), which it wraps,
583 and also by the need to do smtp command/response handling.
585 Arguments: lim (ignored)
586 Returns: the next character or ERR, EOD or EOF
590 bdat_getc(unsigned lim)
592 uschar * user_msg = NULL;
601 if (chunking_data_left > 0)
602 return lwr_receive_getc(chunking_data_left--);
604 receive_getc = lwr_receive_getc;
605 receive_getbuf = lwr_receive_getbuf;
606 receive_ungetc = lwr_receive_ungetc;
608 dkim_save = dkim_collect_input;
609 dkim_collect_input = FALSE;
612 /* Unless PIPELINING was offered, there should be no next command
613 until after we ack that chunk */
615 if (!pipelining_advertised && !check_sync())
617 unsigned n = smtp_inend - smtp_inptr;
620 incomplete_transaction_log(US"sync failure");
621 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP protocol synchronization error "
622 "(next input sent too soon: pipelining was not advertised): "
623 "rejected \"%s\" %s next input=\"%s\"%s",
624 smtp_cmd_buffer, host_and_ident(TRUE),
625 string_printing(string_copyn(smtp_inptr, n)),
626 smtp_inend - smtp_inptr > n ? "..." : "");
627 (void) synprot_error(L_smtp_protocol_error, 554, NULL,
628 US"SMTP synchronization error");
629 goto repeat_until_rset;
632 /* If not the last, ack the received chunk. The last response is delayed
633 until after the data ACL decides on it */
635 if (chunking_state == CHUNKING_LAST)
638 dkim_exim_verify_feed(NULL, 0); /* notify EOD */
643 smtp_printf("250 %u byte chunk received\r\n", FALSE, chunking_datasize);
644 chunking_state = CHUNKING_OFFERED;
645 DEBUG(D_receive) debug_printf("chunking state %d\n", (int)chunking_state);
647 /* Expect another BDAT cmd from input. RFC 3030 says nothing about
648 QUIT, RSET or NOOP but handling them seems obvious */
651 switch(smtp_read_command(TRUE, 1))
654 (void) synprot_error(L_smtp_protocol_error, 503, NULL,
655 US"only BDAT permissible after non-LAST BDAT");
658 switch(smtp_read_command(TRUE, 1))
660 case QUIT_CMD: smtp_quit_handler(&user_msg, &log_msg); /*FALLTHROUGH */
661 case EOF_CMD: return EOF;
662 case RSET_CMD: smtp_rset_handler(); return ERR;
663 default: if (synprot_error(L_smtp_protocol_error, 503, NULL,
664 US"only RSET accepted now") > 0)
666 goto repeat_until_rset;
670 smtp_quit_handler(&user_msg, &log_msg);
681 smtp_printf("250 OK\r\n", FALSE);
688 if (sscanf(CS smtp_cmd_data, "%u %n", &chunking_datasize, &n) < 1)
690 (void) synprot_error(L_smtp_protocol_error, 501, NULL,
691 US"missing size for BDAT command");
694 chunking_state = strcmpic(smtp_cmd_data+n, US"LAST") == 0
695 ? CHUNKING_LAST : CHUNKING_ACTIVE;
696 chunking_data_left = chunking_datasize;
697 DEBUG(D_receive) debug_printf("chunking state %d, %d bytes\n",
698 (int)chunking_state, chunking_data_left);
700 if (chunking_datasize == 0)
701 if (chunking_state == CHUNKING_LAST)
705 (void) synprot_error(L_smtp_protocol_error, 504, NULL,
706 US"zero size for BDAT command");
707 goto repeat_until_rset;
710 receive_getc = bdat_getc;
711 receive_getbuf = bdat_getbuf; /* r~getbuf is never actually used */
712 receive_ungetc = bdat_ungetc;
714 dkim_collect_input = dkim_save;
716 break; /* to top of main loop */
723 bdat_getbuf(unsigned * len)
727 if (chunking_data_left <= 0)
728 { *len = 0; return NULL; }
730 if (*len > chunking_data_left) *len = chunking_data_left;
731 buf = lwr_receive_getbuf(len); /* Either smtp_getbuf or tls_getbuf */
732 chunking_data_left -= *len;
737 bdat_flush_data(void)
739 while (chunking_data_left)
741 unsigned n = chunking_data_left;
742 if (!bdat_getbuf(&n)) break;
745 receive_getc = lwr_receive_getc;
746 receive_getbuf = lwr_receive_getbuf;
747 receive_ungetc = lwr_receive_ungetc;
749 if (chunking_state != CHUNKING_LAST)
751 chunking_state = CHUNKING_OFFERED;
752 DEBUG(D_receive) debug_printf("chunking state %d\n", (int)chunking_state);
759 /*************************************************
760 * SMTP version of ungetc() *
761 *************************************************/
763 /* Puts a character back in the input buffer. Only ever
769 Returns: the character
783 chunking_data_left++;
784 return lwr_receive_ungetc(ch);
789 /*************************************************
790 * SMTP version of feof() *
791 *************************************************/
793 /* Tests for a previous EOF
796 Returns: non-zero if the eof flag is set
808 /*************************************************
809 * SMTP version of ferror() *
810 *************************************************/
812 /* Tests for a previous read error, and returns with errno
813 restored to what it was when the error was detected.
816 Returns: non-zero if the error flag is set
822 errno = smtp_had_error;
823 return smtp_had_error;
828 /*************************************************
829 * Test for characters in the SMTP buffer *
830 *************************************************/
832 /* Used at the end of a message
841 return smtp_inptr < smtp_inend;
846 /*************************************************
847 * Write formatted string to SMTP channel *
848 *************************************************/
850 /* This is a separate function so that we don't have to repeat everything for
851 TLS support or debugging. It is global so that the daemon and the
852 authentication functions can use it. It does not return any error indication,
853 because major problems such as dropped connections won't show up till an output
854 flush for non-TLS connections. The smtp_fflush() function is available for
855 checking that: for convenience, TLS output errors are remembered here so that
856 they are also picked up later by smtp_fflush().
860 more further data expected
861 ... optional arguments
867 smtp_printf(const char *format, BOOL more, ...)
872 smtp_vprintf(format, more, ap);
876 /* This is split off so that verify.c:respond_printf() can, in effect, call
877 smtp_printf(), bearing in mind that in C a vararg function can't directly
878 call another vararg function, only a function which accepts a va_list. */
881 smtp_vprintf(const char *format, BOOL more, va_list ap)
885 yield = string_vformat(big_buffer, big_buffer_size, format, ap);
889 void *reset_point = store_get(0);
890 uschar *msg_copy, *cr, *end;
891 msg_copy = string_copy(big_buffer);
892 end = msg_copy + Ustrlen(msg_copy);
893 while ((cr = Ustrchr(msg_copy, '\r')) != NULL) /* lose CRs */
894 memmove(cr, cr + 1, (end--) - cr);
895 debug_printf("SMTP>> %s", msg_copy);
896 store_reset(reset_point);
901 log_write(0, LOG_MAIN|LOG_PANIC, "string too large in smtp_printf()");
902 smtp_closedown(US"Unexpected error");
903 exim_exit(EXIT_FAILURE, NULL);
906 /* If this is the first output for a (non-batch) RCPT command, see if all RCPTs
907 have had the same. Note: this code is also present in smtp_respond(). It would
908 be tidier to have it only in one place, but when it was added, it was easier to
909 do it that way, so as not to have to mess with the code for the RCPT command,
910 which sometimes uses smtp_printf() and sometimes smtp_respond(). */
912 if (rcpt_in_progress)
914 if (rcpt_smtp_response == NULL)
915 rcpt_smtp_response = string_copy(big_buffer);
916 else if (rcpt_smtp_response_same &&
917 Ustrcmp(rcpt_smtp_response, big_buffer) != 0)
918 rcpt_smtp_response_same = FALSE;
919 rcpt_in_progress = FALSE;
922 /* Now write the string */
925 if (tls_in.active >= 0)
927 if (tls_write(TRUE, big_buffer, Ustrlen(big_buffer), more) < 0)
928 smtp_write_error = -1;
933 if (fprintf(smtp_out, "%s", big_buffer) < 0) smtp_write_error = -1;
938 /*************************************************
939 * Flush SMTP out and check for error *
940 *************************************************/
942 /* This function isn't currently used within Exim (it detects errors when it
943 tries to read the next SMTP input), but is available for use in local_scan().
944 For non-TLS connections, it flushes the output and checks for errors. For
945 TLS-connections, it checks for a previously-detected TLS write error.
948 Returns: 0 for no error; -1 after an error
954 if (tls_in.active < 0 && fflush(smtp_out) != 0) smtp_write_error = -1;
955 return smtp_write_error;
960 /*************************************************
961 * SMTP command read timeout *
962 *************************************************/
964 /* Signal handler for timing out incoming SMTP commands. This attempts to
967 Argument: signal number (SIGALRM)
972 command_timeout_handler(int sig)
974 had_command_timeout = sig;
979 /*************************************************
981 *************************************************/
983 /* Signal handler for handling SIGTERM. Again, try to finish tidily.
985 Argument: signal number (SIGTERM)
990 command_sigterm_handler(int sig)
992 had_command_sigterm = sig;
999 /*************************************************
1000 * Restore socket timeout to previous value *
1001 *************************************************/
1002 /* If the previous value was successfully retrieved, restore
1003 it before returning control to the non-proxy routines
1005 Arguments: fd - File descriptor for input
1006 get_ok - Successfully retrieved previous values
1007 tvtmp - Time struct with previous values
1008 vslen - Length of time struct
1012 restore_socket_timeout(int fd, int get_ok, struct timeval * tvtmp, socklen_t vslen)
1015 (void) setsockopt(fd, SOL_SOCKET, SO_RCVTIMEO, CS tvtmp, vslen);
1018 /*************************************************
1019 * Check if host is required proxy host *
1020 *************************************************/
1021 /* The function determines if inbound host will be a regular smtp host
1022 or if it is configured that it must use Proxy Protocol. A local
1030 check_proxy_protocol_host()
1034 if ( sender_host_address
1035 && (rc = verify_check_this_host(CUSS &hosts_proxy, NULL, NULL,
1036 sender_host_address, NULL)) == OK)
1039 debug_printf("Detected proxy protocol configured host\n");
1040 proxy_session = TRUE;
1042 return proxy_session;
1046 /*************************************************
1047 * Read data until newline or end of buffer *
1048 *************************************************/
1049 /* While SMTP is server-speaks-first, TLS is client-speaks-first, so we can't
1050 read an entire buffer and assume there will be nothing past a proxy protocol
1051 header. Our approach normally is to use stdio, but again that relies upon
1052 "STARTTLS\r\n" and a server response before the client starts TLS handshake, or
1053 reading _nothing_ before client TLS handshake. So we don't want to use the
1054 usual buffering reads which may read enough to block TLS starting.
1056 So unfortunately we're down to "read one byte at a time, with a syscall each,
1057 and expect a little overhead", for all proxy-opened connections which are v1,
1058 just to handle the TLS-on-connect case. Since SSL functions wrap the
1059 underlying fd, we can't assume that we can feed them any already-read content.
1061 We need to know where to read to, the max capacity, and we'll read until we
1062 get a CR and one more character. Let the caller scream if it's CR+!LF.
1064 Return the amount read.
1068 swallow_until_crlf(int fd, uschar *base, int already, int capacity)
1070 uschar *to = base + already;
1076 /* For "PROXY UNKNOWN\r\n" we, at time of writing, expect to have read
1077 up through the \r; for the _normal_ case, we haven't yet seen the \r. */
1079 cr = memchr(base, '\r', already);
1082 if ((cr - base) < already - 1)
1084 /* \r and presumed \n already within what we have; probably not
1085 actually proxy protocol, but abort cleanly. */
1088 /* \r is last character read, just need one more. */
1092 while (capacity > 0)
1094 do { ret = recv(fd, to, 1, 0); } while (ret == -1 && errno == EINTR);
1106 /* reached end without having room for a final newline, abort */
1111 /*************************************************
1112 * Setup host for proxy protocol *
1113 *************************************************/
1114 /* The function configures the connection based on a header from the
1115 inbound host to use Proxy Protocol. The specification is very exact
1116 so exit with an error if do not find the exact required pieces. This
1117 includes an incorrect number of spaces separating args.
1120 Returns: Boolean success
1124 setup_proxy_protocol_host()
1136 struct { /* TCP/UDP over IPv4, len = 12 */
1142 struct { /* TCP/UDP over IPv6, len = 36 */
1143 uint8_t src_addr[16];
1144 uint8_t dst_addr[16];
1148 struct { /* AF_UNIX sockets, len = 216 */
1149 uschar src_addr[108];
1150 uschar dst_addr[108];
1156 /* Temp variables used in PPv2 address:port parsing */
1158 char tmpip[INET_ADDRSTRLEN];
1159 struct sockaddr_in tmpaddr;
1160 char tmpip6[INET6_ADDRSTRLEN];
1161 struct sockaddr_in6 tmpaddr6;
1163 /* We can't read "all data until end" because while SMTP is
1164 server-speaks-first, the TLS handshake is client-speaks-first, so for
1165 TLS-on-connect ports the proxy protocol header will usually be immediately
1166 followed by a TLS handshake, and with N TLS libraries, we can't reliably
1167 reinject data for reading by those. So instead we first read "enough to be
1168 safely read within the header, and figure out how much more to read".
1169 For v1 we will later read to the end-of-line, for v2 we will read based upon
1172 The v2 sig is 12 octets, and another 4 gets us the length, so we know how much
1173 data is needed total. For v1, where the line looks like:
1174 PROXY TCPn L3src L3dest SrcPort DestPort \r\n
1176 However, for v1 there's also `PROXY UNKNOWN\r\n` which is only 15 octets.
1177 We seem to support that. So, if we read 14 octets then we can tell if we're
1178 v2 or v1. If we're v1, we can continue reading as normal.
1180 If we're v2, we can't slurp up the entire header. We need the length in the
1181 15th & 16th octets, then to read everything after that.
1183 So to safely handle v1 and v2, with client-sent-first supported correctly,
1184 we have to do a minimum of 3 read calls, not 1. Eww.
1187 #define PROXY_INITIAL_READ 14
1188 #define PROXY_V2_HEADER_SIZE 16
1189 #if PROXY_INITIAL_READ > PROXY_V2_HEADER_SIZE
1190 # error Code bug in sizes of data to read for proxy usage
1195 int fd = fileno(smtp_in);
1196 const char v2sig[12] = "\x0D\x0A\x0D\x0A\x00\x0D\x0A\x51\x55\x49\x54\x0A";
1197 uschar * iptype; /* To display debug info */
1199 struct timeval tvtmp;
1200 socklen_t vslen = sizeof(struct timeval);
1203 /* Save current socket timeout values */
1204 get_ok = getsockopt(fd, SOL_SOCKET, SO_RCVTIMEO, CS &tvtmp, &vslen);
1206 /* Proxy Protocol host must send header within a short time
1207 (default 3 seconds) or it's considered invalid */
1208 tv.tv_sec = PROXY_NEGOTIATION_TIMEOUT_SEC;
1209 tv.tv_usec = PROXY_NEGOTIATION_TIMEOUT_USEC;
1210 if (setsockopt(fd, SOL_SOCKET, SO_RCVTIMEO, CS &tv, sizeof(tv)) < 0)
1215 /* The inbound host was declared to be a Proxy Protocol host, so
1216 don't do a PEEK into the data, actually slurp up enough to be
1217 "safe". Can't take it all because TLS-on-connect clients follow
1218 immediately with TLS handshake. */
1219 ret = recv(fd, &hdr, PROXY_INITIAL_READ, 0);
1221 while (ret == -1 && errno == EINTR);
1226 /* For v2, handle reading the length, and then the rest. */
1227 if ((ret == PROXY_INITIAL_READ) && (memcmp(&hdr.v2, v2sig, sizeof(v2sig)) == 0))
1232 /* First get the length fields. */
1235 retmore = recv(fd, (uschar*)&hdr + ret, PROXY_V2_HEADER_SIZE - PROXY_INITIAL_READ, 0);
1236 } while (retmore == -1 && errno == EINTR);
1241 ver = (hdr.v2.ver_cmd & 0xf0) >> 4;
1243 /* May 2014: haproxy combined the version and command into one byte to
1244 allow two full bytes for the length field in order to proxy SSL
1245 connections. SSL Proxy is not supported in this version of Exim, but
1246 must still separate values here. */
1250 DEBUG(D_receive) debug_printf("Invalid Proxy Protocol version: %d\n", ver);
1254 /* The v2 header will always be 16 bytes per the spec. */
1255 size = 16 + ntohs(hdr.v2.len);
1256 DEBUG(D_receive) debug_printf("Detected PROXYv2 header, size %d (limit %d)\n",
1257 size, (int)sizeof(hdr));
1259 /* We should now have 16 octets (PROXY_V2_HEADER_SIZE), and we know the total
1260 amount that we need. Double-check that the size is not unreasonable, then
1262 if (size > sizeof(hdr))
1264 DEBUG(D_receive) debug_printf("PROXYv2 header size unreasonably large; security attack?\n");
1272 retmore = recv(fd, (uschar*)&hdr + ret, size-ret, 0);
1273 } while (retmore == -1 && errno == EINTR);
1277 DEBUG(D_receive) debug_printf("PROXYv2: have %d/%d required octets\n", ret, size);
1278 } while (ret < size);
1280 } /* end scope for getting rest of data for v2 */
1282 /* At this point: if PROXYv2, we've read the exact size required for all data;
1283 if PROXYv1 then we've read "less than required for any valid line" and should
1286 if (ret >= 16 && memcmp(&hdr.v2, v2sig, 12) == 0)
1288 uint8_t cmd = (hdr.v2.ver_cmd & 0x0f);
1292 case 0x01: /* PROXY command */
1295 case 0x11: /* TCPv4 address type */
1297 tmpaddr.sin_addr.s_addr = hdr.v2.addr.ip4.src_addr;
1298 inet_ntop(AF_INET, &tmpaddr.sin_addr, CS &tmpip, sizeof(tmpip));
1299 if (!string_is_ip_address(US tmpip, NULL))
1301 DEBUG(D_receive) debug_printf("Invalid %s source IP\n", iptype);
1304 proxy_local_address = sender_host_address;
1305 sender_host_address = string_copy(US tmpip);
1306 tmpport = ntohs(hdr.v2.addr.ip4.src_port);
1307 proxy_local_port = sender_host_port;
1308 sender_host_port = tmpport;
1309 /* Save dest ip/port */
1310 tmpaddr.sin_addr.s_addr = hdr.v2.addr.ip4.dst_addr;
1311 inet_ntop(AF_INET, &tmpaddr.sin_addr, CS &tmpip, sizeof(tmpip));
1312 if (!string_is_ip_address(US tmpip, NULL))
1314 DEBUG(D_receive) debug_printf("Invalid %s dest port\n", iptype);
1317 proxy_external_address = string_copy(US tmpip);
1318 tmpport = ntohs(hdr.v2.addr.ip4.dst_port);
1319 proxy_external_port = tmpport;
1321 case 0x21: /* TCPv6 address type */
1323 memmove(tmpaddr6.sin6_addr.s6_addr, hdr.v2.addr.ip6.src_addr, 16);
1324 inet_ntop(AF_INET6, &tmpaddr6.sin6_addr, CS &tmpip6, sizeof(tmpip6));
1325 if (!string_is_ip_address(US tmpip6, NULL))
1327 DEBUG(D_receive) debug_printf("Invalid %s source IP\n", iptype);
1330 proxy_local_address = sender_host_address;
1331 sender_host_address = string_copy(US tmpip6);
1332 tmpport = ntohs(hdr.v2.addr.ip6.src_port);
1333 proxy_local_port = sender_host_port;
1334 sender_host_port = tmpport;
1335 /* Save dest ip/port */
1336 memmove(tmpaddr6.sin6_addr.s6_addr, hdr.v2.addr.ip6.dst_addr, 16);
1337 inet_ntop(AF_INET6, &tmpaddr6.sin6_addr, CS &tmpip6, sizeof(tmpip6));
1338 if (!string_is_ip_address(US tmpip6, NULL))
1340 DEBUG(D_receive) debug_printf("Invalid %s dest port\n", iptype);
1343 proxy_external_address = string_copy(US tmpip6);
1344 tmpport = ntohs(hdr.v2.addr.ip6.dst_port);
1345 proxy_external_port = tmpport;
1349 debug_printf("Unsupported PROXYv2 connection type: 0x%02x\n",
1353 /* Unsupported protocol, keep local connection address */
1355 case 0x00: /* LOCAL command */
1356 /* Keep local connection address for LOCAL */
1361 debug_printf("Unsupported PROXYv2 command: 0x%x\n", cmd);
1365 else if (ret >= 8 && memcmp(hdr.v1.line, "PROXY", 5) == 0)
1369 uschar *sp; /* Utility variables follow */
1374 /* get the rest of the line */
1375 r2 = swallow_until_crlf(fd, (uschar*)&hdr, ret, sizeof(hdr)-ret);
1380 p = string_copy(hdr.v1.line);
1381 end = memchr(p, '\r', ret - 1);
1383 if (!end || (end == (uschar*)&hdr + ret) || end[1] != '\n')
1385 DEBUG(D_receive) debug_printf("Partial or invalid PROXY header\n");
1388 *end = '\0'; /* Terminate the string */
1389 size = end + 2 - p; /* Skip header + CRLF */
1390 DEBUG(D_receive) debug_printf("Detected PROXYv1 header\n");
1391 DEBUG(D_receive) debug_printf("Bytes read not within PROXY header: %d\n", ret - size);
1392 /* Step through the string looking for the required fields. Ensure
1393 strict adherence to required formatting, exit for any error. */
1395 if (!isspace(*(p++)))
1397 DEBUG(D_receive) debug_printf("Missing space after PROXY command\n");
1400 if (!Ustrncmp(p, CCS"TCP4", 4))
1402 else if (!Ustrncmp(p,CCS"TCP6", 4))
1404 else if (!Ustrncmp(p,CCS"UNKNOWN", 7))
1406 iptype = US"Unknown";
1411 DEBUG(D_receive) debug_printf("Invalid TCP type\n");
1415 p += Ustrlen(iptype);
1416 if (!isspace(*(p++)))
1418 DEBUG(D_receive) debug_printf("Missing space after TCP4/6 command\n");
1421 /* Find the end of the arg */
1422 if ((sp = Ustrchr(p, ' ')) == NULL)
1425 debug_printf("Did not find proxied src %s\n", iptype);
1429 if(!string_is_ip_address(p, NULL))
1432 debug_printf("Proxied src arg is not an %s address\n", iptype);
1435 proxy_local_address = sender_host_address;
1436 sender_host_address = p;
1438 if ((sp = Ustrchr(p, ' ')) == NULL)
1441 debug_printf("Did not find proxy dest %s\n", iptype);
1445 if(!string_is_ip_address(p, NULL))
1448 debug_printf("Proxy dest arg is not an %s address\n", iptype);
1451 proxy_external_address = p;
1453 if ((sp = Ustrchr(p, ' ')) == NULL)
1455 DEBUG(D_receive) debug_printf("Did not find proxied src port\n");
1459 tmp_port = strtol(CCS p, &endc, 10);
1460 if (*endc || tmp_port == 0)
1463 debug_printf("Proxied src port '%s' not an integer\n", p);
1466 proxy_local_port = sender_host_port;
1467 sender_host_port = tmp_port;
1469 if ((sp = Ustrchr(p, '\0')) == NULL)
1471 DEBUG(D_receive) debug_printf("Did not find proxy dest port\n");
1474 tmp_port = strtol(CCS p, &endc, 10);
1475 if (*endc || tmp_port == 0)
1478 debug_printf("Proxy dest port '%s' not an integer\n", p);
1481 proxy_external_port = tmp_port;
1482 /* Already checked for /r /n above. Good V1 header received. */
1486 /* Wrong protocol */
1487 DEBUG(D_receive) debug_printf("Invalid proxy protocol version negotiation\n");
1488 (void) swallow_until_crlf(fd, (uschar*)&hdr, ret, sizeof(hdr)-ret);
1494 debug_printf("Valid %s sender from Proxy Protocol header\n", iptype);
1495 yield = proxy_session;
1497 /* Don't flush any potential buffer contents. Any input on proxyfail
1498 should cause a synchronization failure */
1501 restore_socket_timeout(fd, get_ok, &tvtmp, vslen);
1506 sender_host_name = NULL;
1507 (void) host_name_lookup();
1508 host_build_sender_fullhost();
1512 proxy_session_failed = TRUE;
1514 debug_printf("Failure to extract proxied host, only QUIT allowed\n");
1521 /*************************************************
1522 * Read one command line *
1523 *************************************************/
1525 /* Strictly, SMTP commands coming over the net are supposed to end with CRLF.
1526 There are sites that don't do this, and in any case internal SMTP probably
1527 should check only for LF. Consequently, we check here for LF only. The line
1528 ends up with [CR]LF removed from its end. If we get an overlong line, treat as
1529 an unknown command. The command is read into the global smtp_cmd_buffer so that
1530 it is available via $smtp_command.
1532 The character reading routine sets up a timeout for each block actually read
1533 from the input (which may contain more than one command). We set up a special
1534 signal handler that closes down the session on a timeout. Control does not
1535 return when it runs.
1538 check_sync if TRUE, check synchronization rules if global option is TRUE
1539 buffer_lim maximum to buffer in lower layer
1541 Returns: a code identifying the command (enumerated above)
1545 smtp_read_command(BOOL check_sync, unsigned buffer_lim)
1550 BOOL hadnull = FALSE;
1552 had_command_timeout = 0;
1553 os_non_restarting_signal(SIGALRM, command_timeout_handler);
1555 while ((c = (receive_getc)(buffer_lim)) != '\n' && c != EOF)
1557 if (ptr >= SMTP_CMD_BUFFER_SIZE)
1559 os_non_restarting_signal(SIGALRM, sigalrm_handler);
1567 smtp_cmd_buffer[ptr++] = c;
1570 receive_linecount++; /* For BSMTP errors */
1571 os_non_restarting_signal(SIGALRM, sigalrm_handler);
1573 /* If hit end of file, return pseudo EOF command. Whether we have a
1574 part-line already read doesn't matter, since this is an error state. */
1576 if (c == EOF) return EOF_CMD;
1578 /* Remove any CR and white space at the end of the line, and terminate the
1581 while (ptr > 0 && isspace(smtp_cmd_buffer[ptr-1])) ptr--;
1582 smtp_cmd_buffer[ptr] = 0;
1584 DEBUG(D_receive) debug_printf("SMTP<< %s\n", smtp_cmd_buffer);
1586 /* NULLs are not allowed in SMTP commands */
1588 if (hadnull) return BADCHAR_CMD;
1590 /* Scan command list and return identity, having set the data pointer
1591 to the start of the actual data characters. Check for SMTP synchronization
1594 for (p = cmd_list; p < cmd_list_end; p++)
1596 #ifdef SUPPORT_PROXY
1597 /* Only allow QUIT command if Proxy Protocol parsing failed */
1598 if (proxy_session && proxy_session_failed && p->cmd != QUIT_CMD)
1602 && strncmpic(smtp_cmd_buffer, US p->name, p->len) == 0
1603 && ( smtp_cmd_buffer[p->len-1] == ':' /* "mail from:" or "rcpt to:" */
1604 || smtp_cmd_buffer[p->len] == 0
1605 || smtp_cmd_buffer[p->len] == ' '
1608 if (smtp_inptr < smtp_inend && /* Outstanding input */
1609 p->cmd < sync_cmd_limit && /* Command should sync */
1610 check_sync && /* Local flag set */
1611 smtp_enforce_sync && /* Global flag set */
1612 sender_host_address != NULL && /* Not local input */
1613 !sender_host_notsocket) /* Really is a socket */
1616 /* The variables $smtp_command and $smtp_command_argument point into the
1617 unmodified input buffer. A copy of the latter is taken for actual
1618 processing, so that it can be chopped up into separate parts if necessary,
1619 for example, when processing a MAIL command options such as SIZE that can
1620 follow the sender address. */
1622 smtp_cmd_argument = smtp_cmd_buffer + p->len;
1623 while (isspace(*smtp_cmd_argument)) smtp_cmd_argument++;
1624 Ustrcpy(smtp_data_buffer, smtp_cmd_argument);
1625 smtp_cmd_data = smtp_data_buffer;
1627 /* Count non-mail commands from those hosts that are controlled in this
1628 way. The default is all hosts. We don't waste effort checking the list
1629 until we get a non-mail command, but then cache the result to save checking
1630 again. If there's a DEFER while checking the host, assume it's in the list.
1632 Note that one instance of RSET, EHLO/HELO, and STARTTLS is allowed at the
1633 start of each incoming message by fiddling with the value in the table. */
1635 if (!p->is_mail_cmd)
1637 if (count_nonmail == TRUE_UNSET) count_nonmail =
1638 verify_check_host(&smtp_accept_max_nonmail_hosts) != FAIL;
1639 if (count_nonmail && ++nonmail_command_count > smtp_accept_max_nonmail)
1640 return TOO_MANY_NONMAIL_CMD;
1643 /* If there is data for a command that does not expect it, generate the
1646 return (p->has_arg || *smtp_cmd_data == 0)? p->cmd : BADARG_CMD;
1650 #ifdef SUPPORT_PROXY
1651 /* Only allow QUIT command if Proxy Protocol parsing failed */
1652 if (proxy_session && proxy_session_failed)
1653 return PROXY_FAIL_IGNORE_CMD;
1656 /* Enforce synchronization for unknown commands */
1658 if ( smtp_inptr < smtp_inend /* Outstanding input */
1659 && check_sync /* Local flag set */
1660 && smtp_enforce_sync /* Global flag set */
1661 && sender_host_address /* Not local input */
1662 && !sender_host_notsocket) /* Really is a socket */
1670 /*************************************************
1671 * Forced closedown of call *
1672 *************************************************/
1674 /* This function is called from log.c when Exim is dying because of a serious
1675 disaster, and also from some other places. If an incoming non-batched SMTP
1676 channel is open, it swallows the rest of the incoming message if in the DATA
1677 phase, sends the reply string, and gives an error to all subsequent commands
1678 except QUIT. The existence of an SMTP call is detected by the non-NULLness of
1682 message SMTP reply string to send, excluding the code
1688 smtp_closedown(uschar *message)
1690 if (!smtp_in || smtp_batched_input) return;
1691 receive_swallow_smtp();
1692 smtp_printf("421 %s\r\n", FALSE, message);
1694 for (;;) switch(smtp_read_command(FALSE, GETC_BUFFER_UNLIMITED))
1700 smtp_printf("221 %s closing connection\r\n", FALSE, smtp_active_hostname);
1705 smtp_printf("250 Reset OK\r\n", FALSE);
1709 smtp_printf("421 %s\r\n", FALSE, message);
1717 /*************************************************
1718 * Set up connection info for logging *
1719 *************************************************/
1721 /* This function is called when logging information about an SMTP connection.
1722 It sets up appropriate source information, depending on the type of connection.
1723 If sender_fullhost is NULL, we are at a very early stage of the connection;
1724 just use the IP address.
1727 Returns: a string describing the connection
1731 smtp_get_connection_info(void)
1733 const uschar * hostname = sender_fullhost
1734 ? sender_fullhost : sender_host_address;
1737 return string_sprintf("SMTP connection from %s", hostname);
1739 if (sender_host_unknown || sender_host_notsocket)
1740 return string_sprintf("SMTP connection from %s", sender_ident);
1743 return string_sprintf("SMTP connection from %s (via inetd)", hostname);
1745 if (LOGGING(incoming_interface) && interface_address != NULL)
1746 return string_sprintf("SMTP connection from %s I=[%s]:%d", hostname,
1747 interface_address, interface_port);
1749 return string_sprintf("SMTP connection from %s", hostname);
1755 /* Append TLS-related information to a log line
1758 g String under construction: allocated string to extend, or NULL
1760 Returns: Allocated string or NULL
1763 s_tlslog(gstring * g)
1765 if (LOGGING(tls_cipher) && tls_in.cipher)
1766 g = string_append(g, 2, US" X=", tls_in.cipher);
1767 if (LOGGING(tls_certificate_verified) && tls_in.cipher)
1768 g = string_append(g, 2, US" CV=", tls_in.certificate_verified? "yes":"no");
1769 if (LOGGING(tls_peerdn) && tls_in.peerdn)
1770 g = string_append(g, 3, US" DN=\"", string_printing(tls_in.peerdn), US"\"");
1771 if (LOGGING(tls_sni) && tls_in.sni)
1772 g = string_append(g, 3, US" SNI=\"", string_printing(tls_in.sni), US"\"");
1777 /*************************************************
1778 * Log lack of MAIL if so configured *
1779 *************************************************/
1781 /* This function is called when an SMTP session ends. If the log selector
1782 smtp_no_mail is set, write a log line giving some details of what has happened
1783 in the SMTP session.
1790 smtp_log_no_mail(void)
1796 if (smtp_mailcmd_count > 0 || !LOGGING(smtp_no_mail))
1799 if (sender_host_authenticated)
1801 g = string_append(g, 2, US" A=", sender_host_authenticated);
1802 if (authenticated_id) g = string_append(g, 2, US":", authenticated_id);
1809 sep = smtp_connection_had[SMTP_HBUFF_SIZE-1] != SCH_NONE ? US" C=..." : US" C=";
1811 for (i = smtp_ch_index; i < SMTP_HBUFF_SIZE; i++)
1812 if (smtp_connection_had[i] != SCH_NONE)
1814 g = string_append(g, 2, sep, smtp_names[smtp_connection_had[i]]);
1818 for (i = 0; i < smtp_ch_index; i++)
1820 g = string_append(g, 2, sep, smtp_names[smtp_connection_had[i]]);
1824 if (!(s = string_from_gstring(g))) s = US"";
1826 log_write(0, LOG_MAIN, "no MAIL in %sSMTP connection from %s D=%s%s",
1827 tcp_in_fastopen ? US"TFO " : US"",
1828 host_and_ident(FALSE), string_timesince(&smtp_connection_start), s);
1832 /* Return list of recent smtp commands */
1838 gstring * list = NULL;
1841 for (i = smtp_ch_index; i < SMTP_HBUFF_SIZE; i++)
1842 if (smtp_connection_had[i] != SCH_NONE)
1843 list = string_append_listele(list, ',', smtp_names[smtp_connection_had[i]]);
1845 for (i = 0; i < smtp_ch_index; i++)
1846 list = string_append_listele(list, ',', smtp_names[smtp_connection_had[i]]);
1848 s = string_from_gstring(list);
1849 return s ? s : US"";
1855 /*************************************************
1856 * Check HELO line and set sender_helo_name *
1857 *************************************************/
1859 /* Check the format of a HELO line. The data for HELO/EHLO is supposed to be
1860 the domain name of the sending host, or an ip literal in square brackets. The
1861 argument is placed in sender_helo_name, which is in malloc store, because it
1862 must persist over multiple incoming messages. If helo_accept_junk is set, this
1863 host is permitted to send any old junk (needed for some broken hosts).
1864 Otherwise, helo_allow_chars can be used for rogue characters in general
1865 (typically people want to let in underscores).
1868 s the data portion of the line (already past any white space)
1870 Returns: TRUE or FALSE
1874 check_helo(uschar *s)
1877 uschar *end = s + Ustrlen(s);
1878 BOOL yield = helo_accept_junk;
1880 /* Discard any previous helo name */
1882 if (sender_helo_name)
1884 store_free(sender_helo_name);
1885 sender_helo_name = NULL;
1888 /* Skip tests if junk is permitted. */
1892 /* Allow the new standard form for IPv6 address literals, namely,
1893 [IPv6:....], and because someone is bound to use it, allow an equivalent
1894 IPv4 form. Allow plain addresses as well. */
1901 if (strncmpic(s, US"[IPv6:", 6) == 0)
1902 yield = (string_is_ip_address(s+6, NULL) == 6);
1903 else if (strncmpic(s, US"[IPv4:", 6) == 0)
1904 yield = (string_is_ip_address(s+6, NULL) == 4);
1906 yield = (string_is_ip_address(s+1, NULL) != 0);
1911 /* Non-literals must be alpha, dot, hyphen, plus any non-valid chars
1912 that have been configured (usually underscore - sigh). */
1915 for (yield = TRUE; *s; s++)
1916 if (!isalnum(*s) && *s != '.' && *s != '-' &&
1917 Ustrchr(helo_allow_chars, *s) == NULL)
1923 /* Save argument if OK */
1925 if (yield) sender_helo_name = string_copy_malloc(start);
1933 /*************************************************
1934 * Extract SMTP command option *
1935 *************************************************/
1937 /* This function picks the next option setting off the end of smtp_cmd_data. It
1938 is called for MAIL FROM and RCPT TO commands, to pick off the optional ESMTP
1939 things that can appear there.
1942 name point this at the name
1943 value point this at the data string
1945 Returns: TRUE if found an option
1949 extract_option(uschar **name, uschar **value)
1952 uschar *v = smtp_cmd_data + Ustrlen(smtp_cmd_data) - 1;
1953 while (isspace(*v)) v--;
1955 while (v > smtp_cmd_data && *v != '=' && !isspace(*v))
1957 /* Take care to not stop at a space embedded in a quoted local-part */
1959 if (*v == '"') do v--; while (*v != '"' && v > smtp_cmd_data+1);
1966 while(isalpha(n[-1])) n--;
1967 /* RFC says SP, but TAB seen in wild and other major MTAs accept it */
1968 if (!isspace(n[-1])) return FALSE;
1974 if (v == smtp_cmd_data) return FALSE;
1986 /*************************************************
1987 * Reset for new message *
1988 *************************************************/
1990 /* This function is called whenever the SMTP session is reset from
1991 within either of the setup functions; also from the daemon loop.
1993 Argument: the stacking pool storage reset point
1998 smtp_reset(void *reset_point)
2000 recipients_list = NULL;
2001 rcpt_count = rcpt_defer_count = rcpt_fail_count =
2002 raw_recipients_count = recipients_count = recipients_list_max = 0;
2003 message_linecount = 0;
2005 acl_added_headers = NULL;
2006 acl_removed_headers = NULL;
2007 queue_only_policy = FALSE;
2008 rcpt_smtp_response = NULL;
2009 rcpt_smtp_response_same = TRUE;
2010 rcpt_in_progress = FALSE;
2011 deliver_freeze = FALSE; /* Can be set by ACL */
2012 freeze_tell = freeze_tell_config; /* Can be set by ACL */
2013 fake_response = OK; /* Can be set by ACL */
2014 #ifdef WITH_CONTENT_SCAN
2015 no_mbox_unspool = FALSE; /* Can be set by ACL */
2017 submission_mode = FALSE; /* Can be set by ACL */
2018 suppress_local_fixups = suppress_local_fixups_default; /* Can be set by ACL */
2019 active_local_from_check = local_from_check; /* Can be set by ACL */
2020 active_local_sender_retain = local_sender_retain; /* Can be set by ACL */
2021 sending_ip_address = NULL;
2022 return_path = sender_address = NULL;
2023 sender_data = NULL; /* Can be set by ACL */
2024 deliver_localpart_parent = deliver_localpart_orig = NULL;
2025 deliver_domain_parent = deliver_domain_orig = NULL;
2026 callout_address = NULL;
2027 submission_name = NULL; /* Can be set by ACL */
2028 raw_sender = NULL; /* After SMTP rewrite, before qualifying */
2029 sender_address_unrewritten = NULL; /* Set only after verify rewrite */
2030 sender_verified_list = NULL; /* No senders verified */
2031 memset(sender_address_cache, 0, sizeof(sender_address_cache));
2032 memset(sender_domain_cache, 0, sizeof(sender_domain_cache));
2034 authenticated_sender = NULL;
2035 #ifdef EXPERIMENTAL_BRIGHTMAIL
2037 bmi_verdicts = NULL;
2039 dnslist_domain = dnslist_matched = NULL;
2040 #ifndef DISABLE_DKIM
2041 dkim_cur_signer = dkim_signers =
2042 dkim_signing_domain = dkim_signing_selector = dkim_signatures = NULL;
2043 dkim_cur_signer = dkim_signers = dkim_signing_domain = dkim_signing_selector = NULL;
2044 dkim_disable_verify = dkim_collect_input = FALSE;
2045 dkim_verify_overall = dkim_verify_status = dkim_verify_reason = NULL;
2046 dkim_key_length = 0;
2047 dkim_verify_signers = US"$dkim_signers";
2049 #ifdef EXPERIMENTAL_DMARC
2050 dmarc_has_been_checked = dmarc_disable_verify = dmarc_enable_forensic = FALSE;
2051 dmarc_ar_header = dmarc_domain_policy = dmarc_forensic_sender =
2052 dmarc_history_file = dmarc_status = dmarc_status_text = dmarc_tld_file =
2053 dmarc_used_domain = NULL;
2057 deliver_host = deliver_host_address = NULL; /* Can be set by ACL */
2058 #ifndef DISABLE_PRDR
2059 prdr_requested = FALSE;
2062 spf_header_comment = spf_received = spf_result = spf_smtp_comment = NULL;
2063 spf_result_guessed = FALSE;
2065 #ifdef EXPERIMENTAL_DMARC
2066 dmarc_has_been_checked = dmarc_disable_verify = dmarc_enable_forensic = FALSE;
2067 dmarc_domain_policy = dmarc_status = dmarc_status_text = dmarc_used_domain = NULL;
2069 #ifdef EXPERIMENTAL_ARC
2070 arc_state = arc_state_reason = NULL;
2073 message_smtputf8 = FALSE;
2075 body_linecount = body_zerocount = 0;
2077 sender_rate = sender_rate_limit = sender_rate_period = NULL;
2078 ratelimiters_mail = NULL; /* Updated by ratelimit ACL condition */
2079 /* Note that ratelimiters_conn persists across resets. */
2081 /* Reset message ACL variables */
2085 /* The message body variables use malloc store. They may be set if this is
2086 not the first message in an SMTP session and the previous message caused them
2087 to be referenced in an ACL. */
2091 store_free(message_body);
2092 message_body = NULL;
2095 if (message_body_end)
2097 store_free(message_body_end);
2098 message_body_end = NULL;
2101 /* Warning log messages are also saved in malloc store. They are saved to avoid
2102 repetition in the same message, but it seems right to repeat them for different
2105 while (acl_warn_logged)
2107 string_item *this = acl_warn_logged;
2108 acl_warn_logged = acl_warn_logged->next;
2111 store_reset(reset_point);
2118 /*************************************************
2119 * Initialize for incoming batched SMTP message *
2120 *************************************************/
2122 /* This function is called from smtp_setup_msg() in the case when
2123 smtp_batched_input is true. This happens when -bS is used to pass a whole batch
2124 of messages in one file with SMTP commands between them. All errors must be
2125 reported by sending a message, and only MAIL FROM, RCPT TO, and DATA are
2126 relevant. After an error on a sender, or an invalid recipient, the remainder
2127 of the message is skipped. The value of received_protocol is already set.
2130 Returns: > 0 message successfully started (reached DATA)
2131 = 0 QUIT read or end of file reached
2132 < 0 should not occur
2136 smtp_setup_batch_msg(void)
2139 void *reset_point = store_get(0);
2141 /* Save the line count at the start of each transaction - single commands
2142 like HELO and RSET count as whole transactions. */
2144 bsmtp_transaction_linecount = receive_linecount;
2146 if ((receive_feof)()) return 0; /* Treat EOF as QUIT */
2148 cancel_cutthrough_connection(TRUE, US"smtp_setup_batch_msg");
2149 smtp_reset(reset_point); /* Reset for start of message */
2151 /* Deal with SMTP commands. This loop is exited by setting done to a POSITIVE
2152 value. The values are 2 larger than the required yield of the function. */
2157 uschar *recipient = NULL;
2158 int start, end, sender_domain, recipient_domain;
2160 switch(smtp_read_command(FALSE, GETC_BUFFER_UNLIMITED))
2162 /* The HELO/EHLO commands set sender_address_helo if they have
2163 valid data; otherwise they are ignored, except that they do
2164 a reset of the state. */
2169 check_helo(smtp_cmd_data);
2173 cancel_cutthrough_connection(TRUE, US"RSET received");
2174 smtp_reset(reset_point);
2175 bsmtp_transaction_linecount = receive_linecount;
2179 /* The MAIL FROM command requires an address as an operand. All we
2180 do here is to parse it for syntactic correctness. The form "<>" is
2181 a special case which converts into an empty string. The start/end
2182 pointers in the original are not used further for this address, as
2183 it is the canonical extracted address which is all that is kept. */
2186 smtp_mailcmd_count++; /* Count for no-mail log */
2187 if (sender_address != NULL)
2188 /* The function moan_smtp_batch() does not return. */
2189 moan_smtp_batch(smtp_cmd_buffer, "503 Sender already given");
2191 if (smtp_cmd_data[0] == 0)
2192 /* The function moan_smtp_batch() does not return. */
2193 moan_smtp_batch(smtp_cmd_buffer, "501 MAIL FROM must have an address operand");
2195 /* Reset to start of message */
2197 cancel_cutthrough_connection(TRUE, US"MAIL received");
2198 smtp_reset(reset_point);
2200 /* Apply SMTP rewrite */
2202 raw_sender = ((rewrite_existflags & rewrite_smtp) != 0)?
2203 rewrite_one(smtp_cmd_data, rewrite_smtp|rewrite_smtp_sender, NULL, FALSE,
2204 US"", global_rewrite_rules) : smtp_cmd_data;
2206 /* Extract the address; the TRUE flag allows <> as valid */
2209 parse_extract_address(raw_sender, &errmess, &start, &end, &sender_domain,
2213 /* The function moan_smtp_batch() does not return. */
2214 moan_smtp_batch(smtp_cmd_buffer, "501 %s", errmess);
2216 sender_address = string_copy(raw_sender);
2218 /* Qualify unqualified sender addresses if permitted to do so. */
2221 && sender_address[0] != 0 && sender_address[0] != '@')
2222 if (allow_unqualified_sender)
2224 sender_address = rewrite_address_qualify(sender_address, FALSE);
2225 DEBUG(D_receive) debug_printf("unqualified address %s accepted "
2226 "and rewritten\n", raw_sender);
2228 /* The function moan_smtp_batch() does not return. */
2230 moan_smtp_batch(smtp_cmd_buffer, "501 sender address must contain "
2235 /* The RCPT TO command requires an address as an operand. All we do
2236 here is to parse it for syntactic correctness. There may be any number
2237 of RCPT TO commands, specifying multiple senders. We build them all into
2238 a data structure that is in argc/argv format. The start/end values
2239 given by parse_extract_address are not used, as we keep only the
2240 extracted address. */
2243 if (!sender_address)
2244 /* The function moan_smtp_batch() does not return. */
2245 moan_smtp_batch(smtp_cmd_buffer, "503 No sender yet given");
2247 if (smtp_cmd_data[0] == 0)
2248 /* The function moan_smtp_batch() does not return. */
2249 moan_smtp_batch(smtp_cmd_buffer,
2250 "501 RCPT TO must have an address operand");
2252 /* Check maximum number allowed */
2254 if (recipients_max > 0 && recipients_count + 1 > recipients_max)
2255 /* The function moan_smtp_batch() does not return. */
2256 moan_smtp_batch(smtp_cmd_buffer, "%s too many recipients",
2257 recipients_max_reject? "552": "452");
2259 /* Apply SMTP rewrite, then extract address. Don't allow "<>" as a
2260 recipient address */
2262 recipient = rewrite_existflags & rewrite_smtp
2263 ? rewrite_one(smtp_cmd_data, rewrite_smtp, NULL, FALSE, US"",
2264 global_rewrite_rules)
2267 recipient = parse_extract_address(recipient, &errmess, &start, &end,
2268 &recipient_domain, FALSE);
2271 /* The function moan_smtp_batch() does not return. */
2272 moan_smtp_batch(smtp_cmd_buffer, "501 %s", errmess);
2274 /* If the recipient address is unqualified, qualify it if permitted. Then
2275 add it to the list of recipients. */
2277 if (!recipient_domain)
2278 if (allow_unqualified_recipient)
2280 DEBUG(D_receive) debug_printf("unqualified address %s accepted\n",
2282 recipient = rewrite_address_qualify(recipient, TRUE);
2284 /* The function moan_smtp_batch() does not return. */
2286 moan_smtp_batch(smtp_cmd_buffer,
2287 "501 recipient address must contain a domain");
2289 receive_add_recipient(recipient, -1);
2293 /* The DATA command is legal only if it follows successful MAIL FROM
2294 and RCPT TO commands. This function is complete when a valid DATA
2295 command is encountered. */
2298 if (!sender_address || recipients_count <= 0)
2299 /* The function moan_smtp_batch() does not return. */
2300 if (!sender_address)
2301 moan_smtp_batch(smtp_cmd_buffer,
2302 "503 MAIL FROM:<sender> command must precede DATA");
2304 moan_smtp_batch(smtp_cmd_buffer,
2305 "503 RCPT TO:<recipient> must precede DATA");
2308 done = 3; /* DATA successfully achieved */
2309 message_ended = END_NOTENDED; /* Indicate in middle of message */
2314 /* The VRFY, EXPN, HELP, ETRN, and NOOP commands are ignored. */
2321 bsmtp_transaction_linecount = receive_linecount;
2332 /* The function moan_smtp_batch() does not return. */
2333 moan_smtp_batch(smtp_cmd_buffer, "501 Unexpected argument data");
2338 /* The function moan_smtp_batch() does not return. */
2339 moan_smtp_batch(smtp_cmd_buffer, "501 Unexpected NULL in SMTP command");
2344 /* The function moan_smtp_batch() does not return. */
2345 moan_smtp_batch(smtp_cmd_buffer, "500 Command unrecognized");
2350 return done - 2; /* Convert yield values */
2357 smtp_log_tls_fail(uschar * errstr)
2359 uschar * conn_info = smtp_get_connection_info();
2361 if (Ustrncmp(conn_info, US"SMTP ", 5) == 0) conn_info += 5;
2362 /* I'd like to get separated H= here, but too hard for now */
2364 log_write(0, LOG_MAIN, "TLS error on %s %s", conn_info, errstr);
2376 struct tcp_info tinfo;
2377 socklen_t len = sizeof(tinfo);
2379 if ( getsockopt(fileno(smtp_out), IPPROTO_TCP, TCP_INFO, &tinfo, &len) == 0
2380 && tinfo.tcpi_state == TCP_SYN_RECV
2383 DEBUG(D_receive) debug_printf("TCP_FASTOPEN mode connection (state TCP_SYN_RECV)\n");
2384 tcp_in_fastopen = TRUE;
2391 /*************************************************
2392 * Start an SMTP session *
2393 *************************************************/
2395 /* This function is called at the start of an SMTP session. Thereafter,
2396 smtp_setup_msg() is called to initiate each separate message. This
2397 function does host-specific testing, and outputs the banner line.
2400 Returns: FALSE if the session can not continue; something has
2401 gone wrong, or the connection to the host is blocked
2405 smtp_start_session(void)
2408 uschar *user_msg, *log_msg;
2413 gettimeofday(&smtp_connection_start, NULL);
2414 for (smtp_ch_index = 0; smtp_ch_index < SMTP_HBUFF_SIZE; smtp_ch_index++)
2415 smtp_connection_had[smtp_ch_index] = SCH_NONE;
2418 /* Default values for certain variables */
2420 helo_seen = esmtp = helo_accept_junk = FALSE;
2421 smtp_mailcmd_count = 0;
2422 count_nonmail = TRUE_UNSET;
2423 synprot_error_count = unknown_command_count = nonmail_command_count = 0;
2424 smtp_delay_mail = smtp_rlm_base;
2425 auth_advertised = FALSE;
2426 pipelining_advertised = FALSE;
2427 pipelining_enable = TRUE;
2428 sync_cmd_limit = NON_SYNC_CMD_NON_PIPELINING;
2429 smtp_exit_function_called = FALSE; /* For avoiding loop in not-quit exit */
2431 /* If receiving by -bs from a trusted user, or testing with -bh, we allow
2432 authentication settings from -oMaa to remain in force. */
2434 if (!host_checking && !sender_host_notsocket)
2435 sender_host_auth_pubname = sender_host_authenticated = NULL;
2436 authenticated_by = NULL;
2439 tls_in.cipher = tls_in.peerdn = NULL;
2440 tls_in.ourcert = tls_in.peercert = NULL;
2442 tls_in.ocsp = OCSP_NOT_REQ;
2443 tls_advertised = FALSE;
2445 dsn_advertised = FALSE;
2447 smtputf8_advertised = FALSE;
2450 /* Reset ACL connection variables */
2454 /* Allow for trailing 0 in the command and data buffers. */
2456 if (!(smtp_cmd_buffer = US malloc(2*SMTP_CMD_BUFFER_SIZE + 2)))
2457 log_write(0, LOG_MAIN|LOG_PANIC_DIE,
2458 "malloc() failed for SMTP command buffer");
2460 smtp_cmd_buffer[0] = 0;
2461 smtp_data_buffer = smtp_cmd_buffer + SMTP_CMD_BUFFER_SIZE + 1;
2463 /* For batched input, the protocol setting can be overridden from the
2464 command line by a trusted caller. */
2466 if (smtp_batched_input)
2468 if (!received_protocol) received_protocol = US"local-bsmtp";
2471 /* For non-batched SMTP input, the protocol setting is forced here. It will be
2472 reset later if any of EHLO/AUTH/STARTTLS are received. */
2476 (sender_host_address ? protocols : protocols_local) [pnormal];
2478 /* Set up the buffer for inputting using direct read() calls, and arrange to
2479 call the local functions instead of the standard C ones. Place a NUL at the
2480 end of the buffer to safety-stop C-string reads from it. */
2482 if (!(smtp_inbuffer = US malloc(IN_BUFFER_SIZE)))
2483 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "malloc() failed for SMTP input buffer");
2484 smtp_inbuffer[IN_BUFFER_SIZE-1] = '\0';
2486 receive_getc = smtp_getc;
2487 receive_getbuf = smtp_getbuf;
2488 receive_get_cache = smtp_get_cache;
2489 receive_ungetc = smtp_ungetc;
2490 receive_feof = smtp_feof;
2491 receive_ferror = smtp_ferror;
2492 receive_smtp_buffered = smtp_buffered;
2493 smtp_inptr = smtp_inend = smtp_inbuffer;
2494 smtp_had_eof = smtp_had_error = 0;
2496 /* Set up the message size limit; this may be host-specific */
2498 thismessage_size_limit = expand_string_integer(message_size_limit, TRUE);
2499 if (expand_string_message)
2501 if (thismessage_size_limit == -1)
2502 log_write(0, LOG_MAIN|LOG_PANIC, "unable to expand message_size_limit: "
2503 "%s", expand_string_message);
2505 log_write(0, LOG_MAIN|LOG_PANIC, "invalid message_size_limit: "
2506 "%s", expand_string_message);
2507 smtp_closedown(US"Temporary local problem - please try later");
2511 /* When a message is input locally via the -bs or -bS options, sender_host_
2512 unknown is set unless -oMa was used to force an IP address, in which case it
2513 is checked like a real remote connection. When -bs is used from inetd, this
2514 flag is not set, causing the sending host to be checked. The code that deals
2515 with IP source routing (if configured) is never required for -bs or -bS and
2516 the flag sender_host_notsocket is used to suppress it.
2518 If smtp_accept_max and smtp_accept_reserve are set, keep some connections in
2519 reserve for certain hosts and/or networks. */
2521 if (!sender_host_unknown)
2524 BOOL reserved_host = FALSE;
2526 /* Look up IP options (source routing info) on the socket if this is not an
2527 -oMa "host", and if any are found, log them and drop the connection.
2529 Linux (and others now, see below) is different to everyone else, so there
2530 has to be some conditional compilation here. Versions of Linux before 2.1.15
2531 used a structure whose name was "options". Somebody finally realized that
2532 this name was silly, and it got changed to "ip_options". I use the
2533 newer name here, but there is a fudge in the script that sets up os.h
2534 to define a macro in older Linux systems.
2536 Sigh. Linux is a fast-moving target. Another generation of Linux uses
2537 glibc 2, which has chosen ip_opts for the structure name. This is now
2538 really a glibc thing rather than a Linux thing, so the condition name
2539 has been changed to reflect this. It is relevant also to GNU/Hurd.
2541 Mac OS 10.x (Darwin) is like the later glibc versions, but without the
2542 setting of the __GLIBC__ macro, so we can't detect it automatically. There's
2543 a special macro defined in the os.h file.
2545 Some DGUX versions on older hardware appear not to support IP options at
2546 all, so there is now a general macro which can be set to cut out this
2549 How to do this properly in IPv6 is not yet known. */
2551 #if !HAVE_IPV6 && !defined(NO_IP_OPTIONS)
2553 #ifdef GLIBC_IP_OPTIONS
2554 #if (!defined __GLIBC__) || (__GLIBC__ < 2)
2559 #elif defined DARWIN_IP_OPTIONS
2565 if (!host_checking && !sender_host_notsocket)
2568 EXIM_SOCKLEN_T optlen = sizeof(struct ip_options) + MAX_IPOPTLEN;
2569 struct ip_options *ipopt = store_get(optlen);
2571 struct ip_opts ipoptblock;
2572 struct ip_opts *ipopt = &ipoptblock;
2573 EXIM_SOCKLEN_T optlen = sizeof(ipoptblock);
2575 struct ipoption ipoptblock;
2576 struct ipoption *ipopt = &ipoptblock;
2577 EXIM_SOCKLEN_T optlen = sizeof(ipoptblock);
2580 /* Occasional genuine failures of getsockopt() have been seen - for
2581 example, "reset by peer". Therefore, just log and give up on this
2582 call, unless the error is ENOPROTOOPT. This error is given by systems
2583 that have the interfaces but not the mechanism - e.g. GNU/Hurd at the time
2584 of writing. So for that error, carry on - we just can't do an IP options
2587 DEBUG(D_receive) debug_printf("checking for IP options\n");
2589 if (getsockopt(fileno(smtp_out), IPPROTO_IP, IP_OPTIONS, US (ipopt),
2592 if (errno != ENOPROTOOPT)
2594 log_write(0, LOG_MAIN, "getsockopt() failed from %s: %s",
2595 host_and_ident(FALSE), strerror(errno));
2596 smtp_printf("451 SMTP service not available\r\n", FALSE);
2601 /* Deal with any IP options that are set. On the systems I have looked at,
2602 the value of MAX_IPOPTLEN has been 40, meaning that there should never be
2603 more logging data than will fit in big_buffer. Nevertheless, after somebody
2604 questioned this code, I've added in some paranoid checking. */
2606 else if (optlen > 0)
2608 uschar *p = big_buffer;
2609 uschar *pend = big_buffer + big_buffer_size;
2610 uschar *opt, *adptr;
2612 struct in_addr addr;
2615 uschar *optstart = US (ipopt->__data);
2617 uschar *optstart = US (ipopt->ip_opts);
2619 uschar *optstart = US (ipopt->ipopt_list);
2622 DEBUG(D_receive) debug_printf("IP options exist\n");
2624 Ustrcpy(p, "IP options on incoming call:");
2627 for (opt = optstart; opt != NULL &&
2628 opt < US (ipopt) + optlen;)
2642 if (!string_format(p, pend-p, " %s [@%s",
2643 (*opt == IPOPT_SSRR)? "SSRR" : "LSRR",
2645 inet_ntoa(*((struct in_addr *)(&(ipopt->faddr))))))
2647 inet_ntoa(ipopt->ip_dst)))
2649 inet_ntoa(ipopt->ipopt_dst)))
2657 optcount = (opt[1] - 3) / sizeof(struct in_addr);
2659 while (optcount-- > 0)
2661 memcpy(&addr, adptr, sizeof(addr));
2662 if (!string_format(p, pend - p - 1, "%s%s",
2663 (optcount == 0)? ":" : "@", inet_ntoa(addr)))
2669 adptr += sizeof(struct in_addr);
2678 if (pend - p < 4 + 3*opt[1]) { opt = NULL; break; }
2681 for (i = 0; i < opt[1]; i++)
2682 p += sprintf(CS p, "%2.2x ", opt[i]);
2691 log_write(0, LOG_MAIN, "%s", big_buffer);
2693 /* Refuse any call with IP options. This is what tcpwrappers 7.5 does. */
2695 log_write(0, LOG_MAIN|LOG_REJECT,
2696 "connection from %s refused (IP options)", host_and_ident(FALSE));
2698 smtp_printf("554 SMTP service not available\r\n", FALSE);
2702 /* Length of options = 0 => there are no options */
2704 else DEBUG(D_receive) debug_printf("no IP options found\n");
2706 #endif /* HAVE_IPV6 && !defined(NO_IP_OPTIONS) */
2708 /* Set keep-alive in socket options. The option is on by default. This
2709 setting is an attempt to get rid of some hanging connections that stick in
2710 read() when the remote end (usually a dialup) goes away. */
2712 if (smtp_accept_keepalive && !sender_host_notsocket)
2713 ip_keepalive(fileno(smtp_out), sender_host_address, FALSE);
2715 /* If the current host matches host_lookup, set the name by doing a
2716 reverse lookup. On failure, sender_host_name will be NULL and
2717 host_lookup_failed will be TRUE. This may or may not be serious - optional
2720 if (verify_check_host(&host_lookup) == OK)
2722 (void)host_name_lookup();
2723 host_build_sender_fullhost();
2726 /* Delay this until we have the full name, if it is looked up. */
2728 set_process_info("handling incoming connection from %s",
2729 host_and_ident(FALSE));
2731 /* Expand smtp_receive_timeout, if needed */
2733 if (smtp_receive_timeout_s)
2736 if ( !(exp = expand_string(smtp_receive_timeout_s))
2738 || (smtp_receive_timeout = readconf_readtime(exp, 0, FALSE)) < 0
2740 log_write(0, LOG_MAIN|LOG_PANIC,
2741 "bad value for smtp_receive_timeout: '%s'", exp ? exp : US"");
2744 /* Test for explicit connection rejection */
2746 if (verify_check_host(&host_reject_connection) == OK)
2748 log_write(L_connection_reject, LOG_MAIN|LOG_REJECT, "refused connection "
2749 "from %s (host_reject_connection)", host_and_ident(FALSE));
2750 smtp_printf("554 SMTP service not available\r\n", FALSE);
2754 /* Test with TCP Wrappers if so configured. There is a problem in that
2755 hosts_ctl() returns 0 (deny) under a number of system failure circumstances,
2756 such as disks dying. In these cases, it is desirable to reject with a 4xx
2757 error instead of a 5xx error. There isn't a "right" way to detect such
2758 problems. The following kludge is used: errno is zeroed before calling
2759 hosts_ctl(). If the result is "reject", a 5xx error is given only if the
2760 value of errno is 0 or ENOENT (which happens if /etc/hosts.{allow,deny} does
2763 #ifdef USE_TCP_WRAPPERS
2765 if (!(tcp_wrappers_name = expand_string(tcp_wrappers_daemon_name)))
2766 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "Expansion of \"%s\" "
2767 "(tcp_wrappers_name) failed: %s", string_printing(tcp_wrappers_name),
2768 expand_string_message);
2770 if (!hosts_ctl(tcp_wrappers_name,
2771 sender_host_name ? CS sender_host_name : STRING_UNKNOWN,
2772 sender_host_address ? CS sender_host_address : STRING_UNKNOWN,
2773 sender_ident ? CS sender_ident : STRING_UNKNOWN))
2775 if (errno == 0 || errno == ENOENT)
2777 HDEBUG(D_receive) debug_printf("tcp wrappers rejection\n");
2778 log_write(L_connection_reject,
2779 LOG_MAIN|LOG_REJECT, "refused connection from %s "
2780 "(tcp wrappers)", host_and_ident(FALSE));
2781 smtp_printf("554 SMTP service not available\r\n", FALSE);
2785 int save_errno = errno;
2786 HDEBUG(D_receive) debug_printf("tcp wrappers rejected with unexpected "
2787 "errno value %d\n", save_errno);
2788 log_write(L_connection_reject,
2789 LOG_MAIN|LOG_REJECT, "temporarily refused connection from %s "
2790 "(tcp wrappers errno=%d)", host_and_ident(FALSE), save_errno);
2791 smtp_printf("451 Temporary local problem - please try later\r\n", FALSE);
2797 /* Check for reserved slots. The value of smtp_accept_count has already been
2798 incremented to include this process. */
2800 if (smtp_accept_max > 0 &&
2801 smtp_accept_count > smtp_accept_max - smtp_accept_reserve)
2803 if ((rc = verify_check_host(&smtp_reserve_hosts)) != OK)
2805 log_write(L_connection_reject,
2806 LOG_MAIN, "temporarily refused connection from %s: not in "
2807 "reserve list: connected=%d max=%d reserve=%d%s",
2808 host_and_ident(FALSE), smtp_accept_count - 1, smtp_accept_max,
2809 smtp_accept_reserve, (rc == DEFER)? " (lookup deferred)" : "");
2810 smtp_printf("421 %s: Too many concurrent SMTP connections; "
2811 "please try again later\r\n", FALSE, smtp_active_hostname);
2814 reserved_host = TRUE;
2817 /* If a load level above which only messages from reserved hosts are
2818 accepted is set, check the load. For incoming calls via the daemon, the
2819 check is done in the superior process if there are no reserved hosts, to
2820 save a fork. In all cases, the load average will already be available
2821 in a global variable at this point. */
2823 if (smtp_load_reserve >= 0 &&
2824 load_average > smtp_load_reserve &&
2826 verify_check_host(&smtp_reserve_hosts) != OK)
2828 log_write(L_connection_reject,
2829 LOG_MAIN, "temporarily refused connection from %s: not in "
2830 "reserve list and load average = %.2f", host_and_ident(FALSE),
2831 (double)load_average/1000.0);
2832 smtp_printf("421 %s: Too much load; please try again later\r\n", FALSE,
2833 smtp_active_hostname);
2837 /* Determine whether unqualified senders or recipients are permitted
2838 for this host. Unfortunately, we have to do this every time, in order to
2839 set the flags so that they can be inspected when considering qualifying
2840 addresses in the headers. For a site that permits no qualification, this
2841 won't take long, however. */
2843 allow_unqualified_sender =
2844 verify_check_host(&sender_unqualified_hosts) == OK;
2846 allow_unqualified_recipient =
2847 verify_check_host(&recipient_unqualified_hosts) == OK;
2849 /* Determine whether HELO/EHLO is required for this host. The requirement
2850 can be hard or soft. */
2852 helo_required = verify_check_host(&helo_verify_hosts) == OK;
2854 helo_verify = verify_check_host(&helo_try_verify_hosts) == OK;
2856 /* Determine whether this hosts is permitted to send syntactic junk
2857 after a HELO or EHLO command. */
2859 helo_accept_junk = verify_check_host(&helo_accept_junk_hosts) == OK;
2862 /* For batch SMTP input we are now done. */
2864 if (smtp_batched_input) return TRUE;
2866 /* If valid Proxy Protocol source is connecting, set up session.
2867 * Failure will not allow any SMTP function other than QUIT. */
2869 #ifdef SUPPORT_PROXY
2870 proxy_session = FALSE;
2871 proxy_session_failed = FALSE;
2872 if (check_proxy_protocol_host())
2873 setup_proxy_protocol_host();
2876 /* Start up TLS if tls_on_connect is set. This is for supporting the legacy
2877 smtps port for use with older style SSL MTAs. */
2880 if (tls_in.on_connect)
2882 if (tls_server_start(tls_require_ciphers, &user_msg) != OK)
2883 return smtp_log_tls_fail(user_msg);
2884 cmd_list[CMD_LIST_TLS_AUTH].is_mail_cmd = TRUE;
2888 /* Run the connect ACL if it exists */
2891 if (acl_smtp_connect)
2894 if ((rc = acl_check(ACL_WHERE_CONNECT, NULL, acl_smtp_connect, &user_msg,
2897 (void) smtp_handle_acl_fail(ACL_WHERE_CONNECT, rc, user_msg, log_msg);
2902 /* Output the initial message for a two-way SMTP connection. It may contain
2903 newlines, which then cause a multi-line response to be given. */
2905 code = US"220"; /* Default status code */
2906 esc = US""; /* Default extended status code */
2907 esclen = 0; /* Length of esc */
2911 if (!(s = expand_string(smtp_banner)))
2912 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "Expansion of \"%s\" (smtp_banner) "
2913 "failed: %s", smtp_banner, expand_string_message);
2919 smtp_message_code(&code, &codelen, &s, NULL, TRUE);
2923 esclen = codelen - 4;
2927 /* Remove any terminating newlines; might as well remove trailing space too */
2930 while (p > s && isspace(p[-1])) p--;
2933 /* It seems that CC:Mail is braindead, and assumes that the greeting message
2934 is all contained in a single IP packet. The original code wrote out the
2935 greeting using several calls to fprint/fputc, and on busy servers this could
2936 cause it to be split over more than one packet - which caused CC:Mail to fall
2937 over when it got the second part of the greeting after sending its first
2938 command. Sigh. To try to avoid this, build the complete greeting message
2939 first, and output it in one fell swoop. This gives a better chance of it
2940 ending up as a single packet. */
2942 ss = string_get(256);
2945 do /* At least once, in case we have an empty string */
2948 uschar *linebreak = Ustrchr(p, '\n');
2949 ss = string_catn(ss, code, 3);
2953 ss = string_catn(ss, US" ", 1);
2957 len = linebreak - p;
2958 ss = string_catn(ss, US"-", 1);
2960 ss = string_catn(ss, esc, esclen);
2961 ss = string_catn(ss, p, len);
2962 ss = string_catn(ss, US"\r\n", 2);
2968 /* Before we write the banner, check that there is no input pending, unless
2969 this synchronisation check is disabled. */
2973 unsigned n = smtp_inend - smtp_inptr;
2976 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP protocol "
2977 "synchronization error (input sent without waiting for greeting): "
2978 "rejected connection from %s input=\"%s\"", host_and_ident(TRUE),
2979 string_printing(string_copyn(smtp_inptr, n)));
2980 smtp_printf("554 SMTP synchronization error\r\n", FALSE);
2984 /* Now output the banner */
2986 smtp_printf("%s", FALSE, string_from_gstring(ss));
2988 /* Attempt to see if we sent the banner before the last ACK of the 3-way
2989 handshake arrived. If so we must have managed a TFO. */
3002 /*************************************************
3003 * Handle SMTP syntax and protocol errors *
3004 *************************************************/
3006 /* Write to the log for SMTP syntax errors in incoming commands, if configured
3007 to do so. Then transmit the error response. The return value depends on the
3008 number of syntax and protocol errors in this SMTP session.
3011 type error type, given as a log flag bit
3012 code response code; <= 0 means don't send a response
3013 data data to reflect in the response (can be NULL)
3014 errmess the error message
3016 Returns: -1 limit of syntax/protocol errors NOT exceeded
3017 +1 limit of syntax/protocol errors IS exceeded
3019 These values fit in with the values of the "done" variable in the main
3020 processing loop in smtp_setup_msg(). */
3023 synprot_error(int type, int code, uschar *data, uschar *errmess)
3027 log_write(type, LOG_MAIN, "SMTP %s error in \"%s\" %s %s",
3028 (type == L_smtp_syntax_error)? "syntax" : "protocol",
3029 string_printing(smtp_cmd_buffer), host_and_ident(TRUE), errmess);
3031 if (++synprot_error_count > smtp_max_synprot_errors)
3034 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
3035 "syntax or protocol errors (last command was \"%s\")",
3036 host_and_ident(FALSE), string_printing(smtp_cmd_buffer));
3041 smtp_printf("%d%c%s%s%s\r\n", FALSE, code, yield == 1 ? '-' : ' ',
3042 data ? data : US"", data ? US": " : US"", errmess);
3044 smtp_printf("%d Too many syntax or protocol errors\r\n", FALSE, code);
3053 /*************************************************
3054 * Send SMTP response, possibly multiline *
3055 *************************************************/
3057 /* There are, it seems, broken clients out there that cannot handle multiline
3058 responses. If no_multiline_responses is TRUE (it can be set from an ACL), we
3059 output nothing for non-final calls, and only the first line for anything else.
3062 code SMTP code, may involve extended status codes
3063 codelen length of smtp code; if > 4 there's an ESC
3064 final FALSE if the last line isn't the final line
3065 msg message text, possibly containing newlines
3071 smtp_respond(uschar* code, int codelen, BOOL final, uschar *msg)
3076 if (!final && no_multiline_responses) return;
3081 esclen = codelen - 4;
3084 /* If this is the first output for a (non-batch) RCPT command, see if all RCPTs
3085 have had the same. Note: this code is also present in smtp_printf(). It would
3086 be tidier to have it only in one place, but when it was added, it was easier to
3087 do it that way, so as not to have to mess with the code for the RCPT command,
3088 which sometimes uses smtp_printf() and sometimes smtp_respond(). */
3090 if (rcpt_in_progress)
3092 if (rcpt_smtp_response == NULL)
3093 rcpt_smtp_response = string_copy(msg);
3094 else if (rcpt_smtp_response_same &&
3095 Ustrcmp(rcpt_smtp_response, msg) != 0)
3096 rcpt_smtp_response_same = FALSE;
3097 rcpt_in_progress = FALSE;
3100 /* Now output the message, splitting it up into multiple lines if necessary.
3101 We only handle pipelining these responses as far as nonfinal/final groups,
3102 not the whole MAIL/RCPT/DATA response set. */
3106 uschar *nl = Ustrchr(msg, '\n');
3109 smtp_printf("%.3s%c%.*s%s\r\n", !final, code, final ? ' ':'-', esclen, esc, msg);
3112 else if (nl[1] == 0 || no_multiline_responses)
3114 smtp_printf("%.3s%c%.*s%.*s\r\n", !final, code, final ? ' ':'-', esclen, esc,
3115 (int)(nl - msg), msg);
3120 smtp_printf("%.3s-%.*s%.*s\r\n", TRUE, code, esclen, esc, (int)(nl - msg), msg);
3122 while (isspace(*msg)) msg++;
3130 /*************************************************
3131 * Parse user SMTP message *
3132 *************************************************/
3134 /* This function allows for user messages overriding the response code details
3135 by providing a suitable response code string at the start of the message
3136 user_msg. Check the message for starting with a response code and optionally an
3137 extended status code. If found, check that the first digit is valid, and if so,
3138 change the code pointer and length to use the replacement. An invalid code
3139 causes a panic log; in this case, if the log messages is the same as the user
3140 message, we must also adjust the value of the log message to show the code that
3141 is actually going to be used (the original one).
3143 This function is global because it is called from receive.c as well as within
3146 Note that the code length returned includes the terminating whitespace
3147 character, which is always included in the regex match.
3150 code SMTP code, may involve extended status codes
3151 codelen length of smtp code; if > 4 there's an ESC
3153 log_msg optional log message, to be adjusted with the new SMTP code
3154 check_valid if true, verify the response code
3160 smtp_message_code(uschar **code, int *codelen, uschar **msg, uschar **log_msg,
3166 if (!msg || !*msg) return;
3168 if ((n = pcre_exec(regex_smtp_code, NULL, CS *msg, Ustrlen(*msg), 0,
3169 PCRE_EOPT, ovector, sizeof(ovector)/sizeof(int))) < 0) return;
3171 if (check_valid && (*msg)[0] != (*code)[0])
3173 log_write(0, LOG_MAIN|LOG_PANIC, "configured error code starts with "
3174 "incorrect digit (expected %c) in \"%s\"", (*code)[0], *msg);
3175 if (log_msg != NULL && *log_msg == *msg)
3176 *log_msg = string_sprintf("%s %s", *code, *log_msg + ovector[1]);
3181 *codelen = ovector[1]; /* Includes final space */
3183 *msg += ovector[1]; /* Chop the code off the message */
3190 /*************************************************
3191 * Handle an ACL failure *
3192 *************************************************/
3194 /* This function is called when acl_check() fails. As well as calls from within
3195 this module, it is called from receive.c for an ACL after DATA. It sorts out
3196 logging the incident, and sends the error response. A message containing
3197 newlines is turned into a multiline SMTP response, but for logging, only the
3200 There's a table of default permanent failure response codes to use in
3201 globals.c, along with the table of names. VFRY is special. Despite RFC1123 it
3202 defaults disabled in Exim. However, discussion in connection with RFC 821bis
3203 (aka RFC 2821) has concluded that the response should be 252 in the disabled
3204 state, because there are broken clients that try VRFY before RCPT. A 5xx
3205 response should be given only when the address is positively known to be
3206 undeliverable. Sigh. We return 252 if there is no VRFY ACL or it provides
3207 no explicit code, but if there is one we let it know best.
3208 Also, for ETRN, 458 is given on refusal, and for AUTH, 503.
3210 From Exim 4.63, it is possible to override the response code details by
3211 providing a suitable response code string at the start of the message provided
3212 in user_msg. The code's first digit is checked for validity.
3215 where where the ACL was called from
3217 user_msg a message that can be included in an SMTP response
3218 log_msg a message for logging
3220 Returns: 0 in most cases
3221 2 if the failure code was FAIL_DROP, in which case the
3222 SMTP connection should be dropped (this value fits with the
3223 "done" variable in smtp_setup_msg() below)
3227 smtp_handle_acl_fail(int where, int rc, uschar *user_msg, uschar *log_msg)
3229 BOOL drop = rc == FAIL_DROP;
3233 uschar *sender_info = US"";
3235 #ifdef WITH_CONTENT_SCAN
3236 where == ACL_WHERE_MIME ? US"during MIME ACL checks" :
3238 where == ACL_WHERE_PREDATA ? US"DATA" :
3239 where == ACL_WHERE_DATA ? US"after DATA" :
3240 #ifndef DISABLE_PRDR
3241 where == ACL_WHERE_PRDR ? US"after DATA PRDR" :
3244 string_sprintf("%s %s", acl_wherenames[where], smtp_cmd_data) :
3245 string_sprintf("%s in \"connect\" ACL", acl_wherenames[where]);
3247 if (drop) rc = FAIL;
3249 /* Set the default SMTP code, and allow a user message to change it. */
3251 smtp_code = rc == FAIL ? acl_wherecodes[where] : US"451";
3252 smtp_message_code(&smtp_code, &codelen, &user_msg, &log_msg,
3253 where != ACL_WHERE_VRFY);
3255 /* We used to have sender_address here; however, there was a bug that was not
3256 updating sender_address after a rewrite during a verify. When this bug was
3257 fixed, sender_address at this point became the rewritten address. I'm not sure
3258 this is what should be logged, so I've changed to logging the unrewritten
3259 address to retain backward compatibility. */
3261 #ifndef WITH_CONTENT_SCAN
3262 if (where == ACL_WHERE_RCPT || where == ACL_WHERE_DATA)
3264 if (where == ACL_WHERE_RCPT || where == ACL_WHERE_DATA || where == ACL_WHERE_MIME)
3267 sender_info = string_sprintf("F=<%s>%s%s%s%s ",
3268 sender_address_unrewritten ? sender_address_unrewritten : sender_address,
3269 sender_host_authenticated ? US" A=" : US"",
3270 sender_host_authenticated ? sender_host_authenticated : US"",
3271 sender_host_authenticated && authenticated_id ? US":" : US"",
3272 sender_host_authenticated && authenticated_id ? authenticated_id : US""
3276 /* If there's been a sender verification failure with a specific message, and
3277 we have not sent a response about it yet, do so now, as a preliminary line for
3278 failures, but not defers. However, always log it for defer, and log it for fail
3279 unless the sender_verify_fail log selector has been turned off. */
3281 if (sender_verified_failed &&
3282 !testflag(sender_verified_failed, af_sverify_told))
3284 BOOL save_rcpt_in_progress = rcpt_in_progress;
3285 rcpt_in_progress = FALSE; /* So as not to treat these as the error */
3287 setflag(sender_verified_failed, af_sverify_told);
3289 if (rc != FAIL || LOGGING(sender_verify_fail))
3290 log_write(0, LOG_MAIN|LOG_REJECT, "%s sender verify %s for <%s>%s",
3291 host_and_ident(TRUE),
3292 ((sender_verified_failed->special_action & 255) == DEFER)? "defer":"fail",
3293 sender_verified_failed->address,
3294 (sender_verified_failed->message == NULL)? US"" :
3295 string_sprintf(": %s", sender_verified_failed->message));
3297 if (rc == FAIL && sender_verified_failed->user_message)
3298 smtp_respond(smtp_code, codelen, FALSE, string_sprintf(
3299 testflag(sender_verified_failed, af_verify_pmfail)?
3300 "Postmaster verification failed while checking <%s>\n%s\n"
3301 "Several RFCs state that you are required to have a postmaster\n"
3302 "mailbox for each mail domain. This host does not accept mail\n"
3303 "from domains whose servers reject the postmaster address."
3305 testflag(sender_verified_failed, af_verify_nsfail)?
3306 "Callback setup failed while verifying <%s>\n%s\n"
3307 "The initial connection, or a HELO or MAIL FROM:<> command was\n"
3308 "rejected. Refusing MAIL FROM:<> does not help fight spam, disregards\n"
3309 "RFC requirements, and stops you from receiving standard bounce\n"
3310 "messages. This host does not accept mail from domains whose servers\n"
3313 "Verification failed for <%s>\n%s",
3314 sender_verified_failed->address,
3315 sender_verified_failed->user_message));
3317 rcpt_in_progress = save_rcpt_in_progress;
3320 /* Sort out text for logging */
3322 log_msg = log_msg ? string_sprintf(": %s", log_msg) : US"";
3323 if ((lognl = Ustrchr(log_msg, '\n'))) *lognl = 0;
3325 /* Send permanent failure response to the command, but the code used isn't
3326 always a 5xx one - see comments at the start of this function. If the original
3327 rc was FAIL_DROP we drop the connection and yield 2. */
3330 smtp_respond(smtp_code, codelen, TRUE,
3331 user_msg ? user_msg : US"Administrative prohibition");
3333 /* Send temporary failure response to the command. Don't give any details,
3334 unless acl_temp_details is set. This is TRUE for a callout defer, a "defer"
3335 verb, and for a header verify when smtp_return_error_details is set.
3337 This conditional logic is all somewhat of a mess because of the odd
3338 interactions between temp_details and return_error_details. One day it should
3339 be re-implemented in a tidier fashion. */
3342 if (acl_temp_details && user_msg)
3344 if ( smtp_return_error_details
3345 && sender_verified_failed
3346 && sender_verified_failed->message
3348 smtp_respond(smtp_code, codelen, FALSE, sender_verified_failed->message);
3350 smtp_respond(smtp_code, codelen, TRUE, user_msg);
3353 smtp_respond(smtp_code, codelen, TRUE,
3354 US"Temporary local problem - please try later");
3356 /* Log the incident to the logs that are specified by log_reject_target
3357 (default main, reject). This can be empty to suppress logging of rejections. If
3358 the connection is not forcibly to be dropped, return 0. Otherwise, log why it
3359 is closing if required and return 2. */
3361 if (log_reject_target != 0)
3364 gstring * g = s_tlslog(NULL);
3365 uschar * tls = string_from_gstring(g);
3366 if (!tls) tls = US"";
3368 uschar * tls = US"";
3370 log_write(where == ACL_WHERE_CONNECT ? L_connection_reject : 0,
3371 log_reject_target, "%s%s%s %s%srejected %s%s",
3372 LOGGING(dnssec) && sender_host_dnssec ? US" DS" : US"",
3373 host_and_ident(TRUE),
3376 rc == FAIL ? US"" : US"temporarily ",
3380 if (!drop) return 0;
3382 log_write(L_smtp_connection, LOG_MAIN, "%s closed by DROP in ACL",
3383 smtp_get_connection_info());
3385 /* Run the not-quit ACL, but without any custom messages. This should not be a
3386 problem, because we get here only if some other ACL has issued "drop", and
3387 in that case, *its* custom messages will have been used above. */
3389 smtp_notquit_exit(US"acl-drop", NULL, NULL);
3396 /*************************************************
3397 * Handle SMTP exit when QUIT is not given *
3398 *************************************************/
3400 /* This function provides a logging/statistics hook for when an SMTP connection
3401 is dropped on the floor or the other end goes away. It's a global function
3402 because it's called from receive.c as well as this module. As well as running
3403 the NOTQUIT ACL, if there is one, this function also outputs a final SMTP
3404 response, either with a custom message from the ACL, or using a default. There
3405 is one case, however, when no message is output - after "drop". In that case,
3406 the ACL that obeyed "drop" has already supplied the custom message, and NULL is
3407 passed to this function.
3409 In case things go wrong while processing this function, causing an error that
3410 may re-enter this function, there is a recursion check.
3413 reason What $smtp_notquit_reason will be set to in the ACL;
3414 if NULL, the ACL is not run
3415 code The error code to return as part of the response
3416 defaultrespond The default message if there's no user_msg
3422 smtp_notquit_exit(uschar *reason, uschar *code, uschar *defaultrespond, ...)
3425 uschar *user_msg = NULL;
3426 uschar *log_msg = NULL;
3428 /* Check for recursive acll */
3430 if (smtp_exit_function_called)
3432 log_write(0, LOG_PANIC, "smtp_notquit_exit() called more than once (%s)",
3436 smtp_exit_function_called = TRUE;
3438 /* Call the not-QUIT ACL, if there is one, unless no reason is given. */
3440 if (acl_smtp_notquit && reason)
3442 smtp_notquit_reason = reason;
3443 if ((rc = acl_check(ACL_WHERE_NOTQUIT, NULL, acl_smtp_notquit, &user_msg,
3444 &log_msg)) == ERROR)
3445 log_write(0, LOG_MAIN|LOG_PANIC, "ACL for not-QUIT returned ERROR: %s",
3449 /* Write an SMTP response if we are expected to give one. As the default
3450 responses are all internal, they should always fit in the buffer, but code a
3451 warning, just in case. Note that string_vformat() still leaves a complete
3452 string, even if it is incomplete. */
3454 if (code && defaultrespond)
3457 smtp_respond(code, 3, TRUE, user_msg);
3462 va_start(ap, defaultrespond);
3463 if (!string_vformat(buffer, sizeof(buffer), CS defaultrespond, ap))
3464 log_write(0, LOG_MAIN|LOG_PANIC, "string too large in smtp_notquit_exit()");
3465 smtp_printf("%s %s\r\n", FALSE, code, buffer);
3475 /*************************************************
3476 * Verify HELO argument *
3477 *************************************************/
3479 /* This function is called if helo_verify_hosts or helo_try_verify_hosts is
3480 matched. It is also called from ACL processing if verify = helo is used and
3481 verification was not previously tried (i.e. helo_try_verify_hosts was not
3482 matched). The result of its processing is to set helo_verified and
3483 helo_verify_failed. These variables should both be FALSE for this function to
3486 Note that EHLO/HELO is legitimately allowed to quote an address literal. Allow
3487 for IPv6 ::ffff: literals.
3490 Returns: TRUE if testing was completed;
3491 FALSE on a temporary failure
3495 smtp_verify_helo(void)
3499 HDEBUG(D_receive) debug_printf("verifying EHLO/HELO argument \"%s\"\n",
3502 if (sender_helo_name == NULL)
3504 HDEBUG(D_receive) debug_printf("no EHLO/HELO command was issued\n");
3507 /* Deal with the case of -bs without an IP address */
3509 else if (sender_host_address == NULL)
3511 HDEBUG(D_receive) debug_printf("no client IP address: assume success\n");
3512 helo_verified = TRUE;
3515 /* Deal with the more common case when there is a sending IP address */
3517 else if (sender_helo_name[0] == '[')
3519 helo_verified = Ustrncmp(sender_helo_name+1, sender_host_address,
3520 Ustrlen(sender_host_address)) == 0;
3525 if (strncmpic(sender_host_address, US"::ffff:", 7) == 0)
3526 helo_verified = Ustrncmp(sender_helo_name + 1,
3527 sender_host_address + 7, Ustrlen(sender_host_address) - 7) == 0;
3532 { if (helo_verified) debug_printf("matched host address\n"); }
3535 /* Do a reverse lookup if one hasn't already given a positive or negative
3536 response. If that fails, or the name doesn't match, try checking with a forward
3541 if (sender_host_name == NULL && !host_lookup_failed)
3542 yield = host_name_lookup() != DEFER;
3544 /* If a host name is known, check it and all its aliases. */
3546 if (sender_host_name)
3547 if ((helo_verified = strcmpic(sender_host_name, sender_helo_name) == 0))
3549 sender_helo_dnssec = sender_host_dnssec;
3550 HDEBUG(D_receive) debug_printf("matched host name\n");
3554 uschar **aliases = sender_host_aliases;
3556 if ((helo_verified = strcmpic(*aliases++, sender_helo_name) == 0))
3558 sender_helo_dnssec = sender_host_dnssec;
3562 HDEBUG(D_receive) if (helo_verified)
3563 debug_printf("matched alias %s\n", *(--aliases));
3566 /* Final attempt: try a forward lookup of the helo name */
3575 h.name = sender_helo_name;
3582 HDEBUG(D_receive) debug_printf("getting IP address for %s\n",
3584 rc = host_find_bydns(&h, NULL, HOST_FIND_BY_A | HOST_FIND_BY_AAAA,
3585 NULL, NULL, NULL, &d, NULL, NULL);
3586 if (rc == HOST_FOUND || rc == HOST_FOUND_LOCAL)
3587 for (hh = &h; hh; hh = hh->next)
3588 if (Ustrcmp(hh->address, sender_host_address) == 0)
3590 helo_verified = TRUE;
3591 if (h.dnssec == DS_YES) sender_helo_dnssec = TRUE;
3594 debug_printf("IP address for %s matches calling address\n"
3595 "Forward DNS security status: %sverified\n",
3596 sender_helo_name, sender_helo_dnssec ? "" : "un");
3603 if (!helo_verified) helo_verify_failed = TRUE; /* We've tried ... */
3610 /*************************************************
3611 * Send user response message *
3612 *************************************************/
3614 /* This function is passed a default response code and a user message. It calls
3615 smtp_message_code() to check and possibly modify the response code, and then
3616 calls smtp_respond() to transmit the response. I put this into a function
3617 just to avoid a lot of repetition.
3620 code the response code
3621 user_msg the user message
3627 smtp_user_msg(uschar *code, uschar *user_msg)
3630 smtp_message_code(&code, &len, &user_msg, NULL, TRUE);
3631 smtp_respond(code, len, TRUE, user_msg);
3637 smtp_in_auth(auth_instance *au, uschar ** s, uschar ** ss)
3639 const uschar *set_id = NULL;
3642 /* Run the checking code, passing the remainder of the command line as
3643 data. Initials the $auth<n> variables as empty. Initialize $0 empty and set
3644 it as the only set numerical variable. The authenticator may set $auth<n>
3645 and also set other numeric variables. The $auth<n> variables are preferred
3646 nowadays; the numerical variables remain for backwards compatibility.
3648 Afterwards, have a go at expanding the set_id string, even if
3649 authentication failed - for bad passwords it can be useful to log the
3650 userid. On success, require set_id to expand and exist, and put it in
3651 authenticated_id. Save this in permanent store, as the working store gets
3652 reset at HELO, RSET, etc. */
3654 for (i = 0; i < AUTH_VARS; i++) auth_vars[i] = NULL;
3656 expand_nlength[0] = 0; /* $0 contains nothing */
3658 rc = (au->info->servercode)(au, smtp_cmd_data);
3659 if (au->set_id) set_id = expand_string(au->set_id);
3660 expand_nmax = -1; /* Reset numeric variables */
3661 for (i = 0; i < AUTH_VARS; i++) auth_vars[i] = NULL; /* Reset $auth<n> */
3663 /* The value of authenticated_id is stored in the spool file and printed in
3664 log lines. It must not contain binary zeros or newline characters. In
3665 normal use, it never will, but when playing around or testing, this error
3666 can (did) happen. To guard against this, ensure that the id contains only
3667 printing characters. */
3669 if (set_id) set_id = string_printing(set_id);
3671 /* For the non-OK cases, set up additional logging data if set_id
3675 set_id = set_id && *set_id
3676 ? string_sprintf(" (set_id=%s)", set_id) : US"";
3678 /* Switch on the result */
3683 if (!au->set_id || set_id) /* Complete success */
3685 if (set_id) authenticated_id = string_copy_malloc(set_id);
3686 sender_host_authenticated = au->name;
3687 sender_host_auth_pubname = au->public_name;
3688 authentication_failed = FALSE;
3689 authenticated_fail_id = NULL; /* Impossible to already be set? */
3692 (sender_host_address ? protocols : protocols_local)
3693 [pextend + pauthed + (tls_in.active >= 0 ? pcrpted:0)];
3694 *s = *ss = US"235 Authentication succeeded";
3695 authenticated_by = au;
3699 /* Authentication succeeded, but we failed to expand the set_id string.
3700 Treat this as a temporary error. */
3702 auth_defer_msg = expand_string_message;
3706 if (set_id) authenticated_fail_id = string_copy_malloc(set_id);
3707 *s = string_sprintf("435 Unable to authenticate at present%s",
3708 auth_defer_user_msg);
3709 *ss = string_sprintf("435 Unable to authenticate at present%s: %s",
3710 set_id, auth_defer_msg);
3714 *s = *ss = US"501 Invalid base64 data";
3718 *s = *ss = US"501 Authentication cancelled";
3722 *s = *ss = US"553 Initial data not expected";
3726 if (set_id) authenticated_fail_id = string_copy_malloc(set_id);
3727 *s = US"535 Incorrect authentication data";
3728 *ss = string_sprintf("535 Incorrect authentication data%s", set_id);
3732 if (set_id) authenticated_fail_id = string_copy_malloc(set_id);
3733 *s = US"435 Internal error";
3734 *ss = string_sprintf("435 Internal error%s: return %d from authentication "
3735 "check", set_id, rc);
3747 qualify_recipient(uschar ** recipient, uschar * smtp_cmd_data, uschar * tag)
3750 if (allow_unqualified_recipient || strcmpic(*recipient, US"postmaster") == 0)
3752 DEBUG(D_receive) debug_printf("unqualified address %s accepted\n",
3754 rd = Ustrlen(recipient) + 1;
3755 *recipient = rewrite_address_qualify(*recipient, TRUE);
3758 smtp_printf("501 %s: recipient address must contain a domain\r\n", FALSE,
3760 log_write(L_smtp_syntax_error,
3761 LOG_MAIN|LOG_REJECT, "unqualified %s rejected: <%s> %s%s",
3762 tag, *recipient, host_and_ident(TRUE), host_lookup_msg);
3770 smtp_quit_handler(uschar ** user_msgp, uschar ** log_msgp)
3773 incomplete_transaction_log(US"QUIT");
3776 int rc = acl_check(ACL_WHERE_QUIT, NULL, acl_smtp_quit, user_msgp, log_msgp);
3778 log_write(0, LOG_MAIN|LOG_PANIC, "ACL for QUIT returned ERROR: %s",
3782 smtp_respond(US"221", 3, TRUE, *user_msgp);
3784 smtp_printf("221 %s closing connection\r\n", FALSE, smtp_active_hostname);
3787 tls_close(TRUE, TLS_SHUTDOWN_NOWAIT);
3790 log_write(L_smtp_connection, LOG_MAIN, "%s closed by QUIT",
3791 smtp_get_connection_info());
3796 smtp_rset_handler(void)
3799 incomplete_transaction_log(US"RSET");
3800 smtp_printf("250 Reset OK\r\n", FALSE);
3801 cmd_list[CMD_LIST_RSET].is_mail_cmd = FALSE;
3806 /*************************************************
3807 * Initialize for SMTP incoming message *
3808 *************************************************/
3810 /* This function conducts the initial dialogue at the start of an incoming SMTP
3811 message, and builds a list of recipients. However, if the incoming message
3812 is part of a batch (-bS option) a separate function is called since it would
3813 be messy having tests splattered about all over this function. This function
3814 therefore handles the case where interaction is occurring. The input and output
3815 files are set up in smtp_in and smtp_out.
3817 The global recipients_list is set to point to a vector of recipient_item
3818 blocks, whose number is given by recipients_count. This is extended by the
3819 receive_add_recipient() function. The global variable sender_address is set to
3820 the sender's address. The yield is +1 if a message has been successfully
3821 started, 0 if a QUIT command was encountered or the connection was refused from
3822 the particular host, or -1 if the connection was lost.
3826 Returns: > 0 message successfully started (reached DATA)
3827 = 0 QUIT read or end of file reached or call refused
3832 smtp_setup_msg(void)
3835 BOOL toomany = FALSE;
3836 BOOL discarded = FALSE;
3837 BOOL last_was_rej_mail = FALSE;
3838 BOOL last_was_rcpt = FALSE;
3839 void *reset_point = store_get(0);
3841 DEBUG(D_receive) debug_printf("smtp_setup_msg entered\n");
3843 /* Reset for start of new message. We allow one RSET not to be counted as a
3844 nonmail command, for those MTAs that insist on sending it between every
3845 message. Ditto for EHLO/HELO and for STARTTLS, to allow for going in and out of
3846 TLS between messages (an Exim client may do this if it has messages queued up
3847 for the host). Note: we do NOT reset AUTH at this point. */
3849 smtp_reset(reset_point);
3850 message_ended = END_NOTSTARTED;
3852 chunking_state = chunking_offered ? CHUNKING_OFFERED : CHUNKING_NOT_OFFERED;
3854 cmd_list[CMD_LIST_RSET].is_mail_cmd = TRUE;
3855 cmd_list[CMD_LIST_HELO].is_mail_cmd = TRUE;
3856 cmd_list[CMD_LIST_EHLO].is_mail_cmd = TRUE;
3858 cmd_list[CMD_LIST_STARTTLS].is_mail_cmd = TRUE;
3861 /* Set the local signal handler for SIGTERM - it tries to end off tidily */
3863 had_command_sigterm = 0;
3864 os_non_restarting_signal(SIGTERM, command_sigterm_handler);
3866 /* Batched SMTP is handled in a different function. */
3868 if (smtp_batched_input) return smtp_setup_batch_msg();
3870 /* Deal with SMTP commands. This loop is exited by setting done to a POSITIVE
3871 value. The values are 2 larger than the required yield of the function. */
3875 const uschar **argv;
3876 uschar *etrn_command;
3877 uschar *etrn_serialize_key;
3879 uschar *log_msg, *smtp_code;
3880 uschar *user_msg = NULL;
3881 uschar *recipient = NULL;
3882 uschar *hello = NULL;
3884 BOOL was_rej_mail = FALSE;
3885 BOOL was_rcpt = FALSE;
3886 void (*oldsignal)(int);
3888 int start, end, sender_domain, recipient_domain;
3892 uschar *orcpt = NULL;
3897 /* Check once per STARTTLS or SSL-on-connect for a TLS AUTH */
3898 if ( tls_in.active >= 0
3900 && tls_in.certificate_verified
3901 && cmd_list[CMD_LIST_TLS_AUTH].is_mail_cmd
3904 cmd_list[CMD_LIST_TLS_AUTH].is_mail_cmd = FALSE;
3906 for (au = auths; au; au = au->next)
3907 if (strcmpic(US"tls", au->driver_name) == 0)
3910 && (rc = acl_check(ACL_WHERE_AUTH, NULL, acl_smtp_auth,
3911 &user_msg, &log_msg)) != OK
3913 done = smtp_handle_acl_fail(ACL_WHERE_AUTH, rc, user_msg, log_msg);
3916 smtp_cmd_data = NULL;
3918 if (smtp_in_auth(au, &s, &ss) == OK)
3919 { DEBUG(D_auth) debug_printf("tls auth succeeded\n"); }
3921 { DEBUG(D_auth) debug_printf("tls auth not succeeded\n"); }
3929 if (smtp_in) /* Avoid pure-ACKs while in cmd pingpong phase */
3930 (void) setsockopt(fileno(smtp_in), IPPROTO_TCP, TCP_QUICKACK,
3931 US &off, sizeof(off));
3934 switch(smtp_read_command(TRUE, GETC_BUFFER_UNLIMITED))
3936 /* The AUTH command is not permitted to occur inside a transaction, and may
3937 occur successfully only once per connection. Actually, that isn't quite
3938 true. When TLS is started, all previous information about a connection must
3939 be discarded, so a new AUTH is permitted at that time.
3941 AUTH may only be used when it has been advertised. However, it seems that
3942 there are clients that send AUTH when it hasn't been advertised, some of
3943 them even doing this after HELO. And there are MTAs that accept this. Sigh.
3944 So there's a get-out that allows this to happen.
3946 AUTH is initially labelled as a "nonmail command" so that one occurrence
3947 doesn't get counted. We change the label here so that multiple failing
3948 AUTHS will eventually hit the nonmail threshold. */
3952 authentication_failed = TRUE;
3953 cmd_list[CMD_LIST_AUTH].is_mail_cmd = FALSE;
3955 if (!auth_advertised && !allow_auth_unadvertised)
3957 done = synprot_error(L_smtp_protocol_error, 503, NULL,
3958 US"AUTH command used when not advertised");
3961 if (sender_host_authenticated)
3963 done = synprot_error(L_smtp_protocol_error, 503, NULL,
3964 US"already authenticated");
3969 done = synprot_error(L_smtp_protocol_error, 503, NULL,
3970 US"not permitted in mail transaction");
3977 && (rc = acl_check(ACL_WHERE_AUTH, NULL, acl_smtp_auth,
3978 &user_msg, &log_msg)) != OK
3981 done = smtp_handle_acl_fail(ACL_WHERE_AUTH, rc, user_msg, log_msg);
3985 /* Find the name of the requested authentication mechanism. */
3988 while ((c = *smtp_cmd_data) != 0 && !isspace(c))
3990 if (!isalnum(c) && c != '-' && c != '_')
3992 done = synprot_error(L_smtp_syntax_error, 501, NULL,
3993 US"invalid character in authentication mechanism name");
3999 /* If not at the end of the line, we must be at white space. Terminate the
4000 name and move the pointer on to any data that may be present. */
4002 if (*smtp_cmd_data != 0)
4004 *smtp_cmd_data++ = 0;
4005 while (isspace(*smtp_cmd_data)) smtp_cmd_data++;
4008 /* Search for an authentication mechanism which is configured for use
4009 as a server and which has been advertised (unless, sigh, allow_auth_
4010 unadvertised is set). */
4012 for (au = auths; au; au = au->next)
4013 if (strcmpic(s, au->public_name) == 0 && au->server &&
4014 (au->advertised || allow_auth_unadvertised))
4019 c = smtp_in_auth(au, &s, &ss);
4021 smtp_printf("%s\r\n", FALSE, s);
4023 log_write(0, LOG_MAIN|LOG_REJECT, "%s authenticator failed for %s: %s",
4024 au->name, host_and_ident(FALSE), ss);
4027 done = synprot_error(L_smtp_protocol_error, 504, NULL,
4028 string_sprintf("%s authentication mechanism not supported", s));
4030 break; /* AUTH_CMD */
4032 /* The HELO/EHLO commands are permitted to appear in the middle of a
4033 session as well as at the beginning. They have the effect of a reset in
4034 addition to their other functions. Their absence at the start cannot be
4035 taken to be an error.
4039 If the EHLO command is not acceptable to the SMTP server, 501, 500,
4040 or 502 failure replies MUST be returned as appropriate. The SMTP
4041 server MUST stay in the same state after transmitting these replies
4042 that it was in before the EHLO was received.
4044 Therefore, we do not do the reset until after checking the command for
4045 acceptability. This change was made for Exim release 4.11. Previously
4046 it did the reset first. */
4059 HELO_EHLO: /* Common code for HELO and EHLO */
4060 cmd_list[CMD_LIST_HELO].is_mail_cmd = FALSE;
4061 cmd_list[CMD_LIST_EHLO].is_mail_cmd = FALSE;
4063 /* Reject the HELO if its argument was invalid or non-existent. A
4064 successful check causes the argument to be saved in malloc store. */
4066 if (!check_helo(smtp_cmd_data))
4068 smtp_printf("501 Syntactically invalid %s argument(s)\r\n", FALSE, hello);
4070 log_write(0, LOG_MAIN|LOG_REJECT, "rejected %s from %s: syntactically "
4071 "invalid argument(s): %s", hello, host_and_ident(FALSE),
4072 (*smtp_cmd_argument == 0)? US"(no argument given)" :
4073 string_printing(smtp_cmd_argument));
4075 if (++synprot_error_count > smtp_max_synprot_errors)
4077 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
4078 "syntax or protocol errors (last command was \"%s\")",
4079 host_and_ident(FALSE), string_printing(smtp_cmd_buffer));
4086 /* If sender_host_unknown is true, we have got here via the -bs interface,
4087 not called from inetd. Otherwise, we are running an IP connection and the
4088 host address will be set. If the helo name is the primary name of this
4089 host and we haven't done a reverse lookup, force one now. If helo_required
4090 is set, ensure that the HELO name matches the actual host. If helo_verify
4091 is set, do the same check, but softly. */
4093 if (!sender_host_unknown)
4095 BOOL old_helo_verified = helo_verified;
4096 uschar *p = smtp_cmd_data;
4098 while (*p != 0 && !isspace(*p)) { *p = tolower(*p); p++; }
4101 /* Force a reverse lookup if HELO quoted something in helo_lookup_domains
4102 because otherwise the log can be confusing. */
4104 if ( !sender_host_name
4105 && (deliver_domain = sender_helo_name, /* set $domain */
4106 match_isinlist(sender_helo_name, CUSS &helo_lookup_domains, 0,
4107 &domainlist_anchor, NULL, MCL_DOMAIN, TRUE, NULL)) == OK)
4108 (void)host_name_lookup();
4110 /* Rebuild the fullhost info to include the HELO name (and the real name
4111 if it was looked up.) */
4113 host_build_sender_fullhost(); /* Rebuild */
4114 set_process_info("handling%s incoming connection from %s",
4115 (tls_in.active >= 0)? " TLS" : "", host_and_ident(FALSE));
4117 /* Verify if configured. This doesn't give much security, but it does
4118 make some people happy to be able to do it. If helo_required is set,
4119 (host matches helo_verify_hosts) failure forces rejection. If helo_verify
4120 is set (host matches helo_try_verify_hosts), it does not. This is perhaps
4121 now obsolescent, since the verification can now be requested selectively
4124 helo_verified = helo_verify_failed = sender_helo_dnssec = FALSE;
4125 if (helo_required || helo_verify)
4127 BOOL tempfail = !smtp_verify_helo();
4132 smtp_printf("%d %s argument does not match calling host\r\n", FALSE,
4133 tempfail? 451 : 550, hello);
4134 log_write(0, LOG_MAIN|LOG_REJECT, "%srejected \"%s %s\" from %s",
4135 tempfail? "temporarily " : "",
4136 hello, sender_helo_name, host_and_ident(FALSE));
4137 helo_verified = old_helo_verified;
4138 break; /* End of HELO/EHLO processing */
4140 HDEBUG(D_all) debug_printf("%s verification failed but host is in "
4141 "helo_try_verify_hosts\n", hello);
4147 /* set up SPF context */
4148 spf_init(sender_helo_name, sender_host_address);
4151 /* Apply an ACL check if one is defined; afterwards, recheck
4152 synchronization in case the client started sending in a delay. */
4155 if ((rc = acl_check(ACL_WHERE_HELO, NULL, acl_smtp_helo,
4156 &user_msg, &log_msg)) != OK)
4158 done = smtp_handle_acl_fail(ACL_WHERE_HELO, rc, user_msg, log_msg);
4159 if (sender_helo_name)
4161 store_free(sender_helo_name);
4162 sender_helo_name = NULL;
4164 host_build_sender_fullhost(); /* Rebuild */
4167 else if (!check_sync()) goto SYNC_FAILURE;
4169 /* Generate an OK reply. The default string includes the ident if present,
4170 and also the IP address if present. Reflecting back the ident is intended
4171 as a deterrent to mail forgers. For maximum efficiency, and also because
4172 some broken systems expect each response to be in a single packet, arrange
4173 that the entire reply is sent in one write(). */
4175 auth_advertised = FALSE;
4176 pipelining_advertised = FALSE;
4178 tls_advertised = FALSE;
4180 dsn_advertised = FALSE;
4182 smtputf8_advertised = FALSE;
4185 smtp_code = US"250 "; /* Default response code plus space*/
4188 s = string_sprintf("%.3s %s Hello %s%s%s",
4190 smtp_active_hostname,
4191 sender_ident ? sender_ident : US"",
4192 sender_ident ? US" at " : US"",
4193 sender_host_name ? sender_host_name : sender_helo_name);
4194 g = string_cat(NULL, s);
4196 if (sender_host_address)
4198 g = string_catn(g, US" [", 2);
4199 g = string_cat (g, sender_host_address);
4200 g = string_catn(g, US"]", 1);
4204 /* A user-supplied EHLO greeting may not contain more than one line. Note
4205 that the code returned by smtp_message_code() includes the terminating
4206 whitespace character. */
4212 smtp_message_code(&smtp_code, &codelen, &user_msg, NULL, TRUE);
4213 s = string_sprintf("%.*s%s", codelen, smtp_code, user_msg);
4214 if ((ss = strpbrk(CS s, "\r\n")) != NULL)
4216 log_write(0, LOG_MAIN|LOG_PANIC, "EHLO/HELO response must not contain "
4217 "newlines: message truncated: %s", string_printing(s));
4220 g = string_cat(NULL, s);
4223 g = string_catn(g, US"\r\n", 2);
4225 /* If we received EHLO, we must create a multiline response which includes
4226 the functions supported. */
4232 /* I'm not entirely happy with this, as an MTA is supposed to check
4233 that it has enough room to accept a message of maximum size before
4234 it sends this. However, there seems little point in not sending it.
4235 The actual size check happens later at MAIL FROM time. By postponing it
4236 till then, VRFY and EXPN can be used after EHLO when space is short. */
4238 if (thismessage_size_limit > 0)
4240 sprintf(CS big_buffer, "%.3s-SIZE %d\r\n", smtp_code,
4241 thismessage_size_limit);
4242 g = string_cat(g, big_buffer);
4246 g = string_catn(g, smtp_code, 3);
4247 g = string_catn(g, US"-SIZE\r\n", 7);
4250 /* Exim does not do protocol conversion or data conversion. It is 8-bit
4251 clean; if it has an 8-bit character in its hand, it just sends it. It
4252 cannot therefore specify 8BITMIME and remain consistent with the RFCs.
4253 However, some users want this option simply in order to stop MUAs
4254 mangling messages that contain top-bit-set characters. It is therefore
4255 provided as an option. */
4257 if (accept_8bitmime)
4259 g = string_catn(g, smtp_code, 3);
4260 g = string_catn(g, US"-8BITMIME\r\n", 11);
4263 /* Advertise DSN support if configured to do so. */
4264 if (verify_check_host(&dsn_advertise_hosts) != FAIL)
4266 g = string_catn(g, smtp_code, 3);
4267 g = string_catn(g, US"-DSN\r\n", 6);
4268 dsn_advertised = TRUE;
4271 /* Advertise ETRN/VRFY/EXPN if there's are ACL checking whether a host is
4272 permitted to issue them; a check is made when any host actually tries. */
4276 g = string_catn(g, smtp_code, 3);
4277 g = string_catn(g, US"-ETRN\r\n", 7);
4281 g = string_catn(g, smtp_code, 3);
4282 g = string_catn(g, US"-VRFY\r\n", 7);
4286 g = string_catn(g, smtp_code, 3);
4287 g = string_catn(g, US"-EXPN\r\n", 7);
4290 /* Exim is quite happy with pipelining, so let the other end know that
4291 it is safe to use it, unless advertising is disabled. */
4293 if (pipelining_enable &&
4294 verify_check_host(&pipelining_advertise_hosts) == OK)
4296 g = string_catn(g, smtp_code, 3);
4297 g = string_catn(g, US"-PIPELINING\r\n", 13);
4298 sync_cmd_limit = NON_SYNC_CMD_PIPELINING;
4299 pipelining_advertised = TRUE;
4303 /* If any server authentication mechanisms are configured, advertise
4304 them if the current host is in auth_advertise_hosts. The problem with
4305 advertising always is that some clients then require users to
4306 authenticate (and aren't configurable otherwise) even though it may not
4307 be necessary (e.g. if the host is in host_accept_relay).
4309 RFC 2222 states that SASL mechanism names contain only upper case
4310 letters, so output the names in upper case, though we actually recognize
4311 them in either case in the AUTH command. */
4315 && !sender_host_authenticated
4317 && verify_check_host(&auth_advertise_hosts) == OK
4322 for (au = auths; au; au = au->next)
4324 au->advertised = FALSE;
4327 DEBUG(D_auth+D_expand) debug_printf_indent(
4328 "Evaluating advertise_condition for %s athenticator\n",
4330 if ( !au->advertise_condition
4331 || expand_check_condition(au->advertise_condition, au->name,
4338 g = string_catn(g, smtp_code, 3);
4339 g = string_catn(g, US"-AUTH", 5);
4341 auth_advertised = TRUE;
4344 g = string_catn(g, US" ", 1);
4345 g = string_cat (g, au->public_name);
4346 while (++saveptr < g->ptr) g->s[saveptr] = toupper(g->s[saveptr]);
4347 au->advertised = TRUE;
4352 if (!first) g = string_catn(g, US"\r\n", 2);
4355 /* RFC 3030 CHUNKING */
4357 if (verify_check_host(&chunking_advertise_hosts) != FAIL)
4359 g = string_catn(g, smtp_code, 3);
4360 g = string_catn(g, US"-CHUNKING\r\n", 11);
4361 chunking_offered = TRUE;
4362 chunking_state = CHUNKING_OFFERED;
4365 /* Advertise TLS (Transport Level Security) aka SSL (Secure Socket Layer)
4366 if it has been included in the binary, and the host matches
4367 tls_advertise_hosts. We must *not* advertise if we are already in a
4368 secure connection. */
4371 if (tls_in.active < 0 &&
4372 verify_check_host(&tls_advertise_hosts) != FAIL)
4374 g = string_catn(g, smtp_code, 3);
4375 g = string_catn(g, US"-STARTTLS\r\n", 11);
4376 tls_advertised = TRUE;
4380 #ifndef DISABLE_PRDR
4381 /* Per Recipient Data Response, draft by Eric A. Hall extending RFC */
4384 g = string_catn(g, smtp_code, 3);
4385 g = string_catn(g, US"-PRDR\r\n", 7);
4390 if ( accept_8bitmime
4391 && verify_check_host(&smtputf8_advertise_hosts) != FAIL)
4393 g = string_catn(g, smtp_code, 3);
4394 g = string_catn(g, US"-SMTPUTF8\r\n", 11);
4395 smtputf8_advertised = TRUE;
4399 /* Finish off the multiline reply with one that is always available. */
4401 g = string_catn(g, smtp_code, 3);
4402 g = string_catn(g, US" HELP\r\n", 7);
4405 /* Terminate the string (for debug), write it, and note that HELO/EHLO
4409 if (tls_in.active >= 0) (void)tls_write(TRUE, g->s, g->ptr, FALSE); else
4413 int i = fwrite(g->s, 1, g->ptr, smtp_out); i = i; /* compiler quietening */
4419 (void) string_from_gstring(g);
4420 while ((cr = Ustrchr(g->s, '\r')) != NULL) /* lose CRs */
4421 memmove(cr, cr + 1, (g->ptr--) - (cr - g->s));
4422 debug_printf("SMTP>> %s", g->s);
4426 /* Reset the protocol and the state, abandoning any previous message. */
4428 (sender_host_address ? protocols : protocols_local)
4430 ? pextend + (sender_host_authenticated ? pauthed : 0)
4432 + (tls_in.active >= 0 ? pcrpted : 0)
4434 cancel_cutthrough_connection(TRUE, US"sent EHLO response");
4435 smtp_reset(reset_point);
4437 break; /* HELO/EHLO */
4440 /* The MAIL command requires an address as an operand. All we do
4441 here is to parse it for syntactic correctness. The form "<>" is
4442 a special case which converts into an empty string. The start/end
4443 pointers in the original are not used further for this address, as
4444 it is the canonical extracted address which is all that is kept. */
4448 smtp_mailcmd_count++; /* Count for limit and ratelimit */
4449 was_rej_mail = TRUE; /* Reset if accepted */
4450 env_mail_type_t * mail_args; /* Sanity check & validate args */
4452 if (helo_required && !helo_seen)
4454 smtp_printf("503 HELO or EHLO required\r\n", FALSE);
4455 log_write(0, LOG_MAIN|LOG_REJECT, "rejected MAIL from %s: no "
4456 "HELO/EHLO given", host_and_ident(FALSE));
4460 if (sender_address != NULL)
4462 done = synprot_error(L_smtp_protocol_error, 503, NULL,
4463 US"sender already given");
4467 if (smtp_cmd_data[0] == 0)
4469 done = synprot_error(L_smtp_protocol_error, 501, NULL,
4470 US"MAIL must have an address operand");
4474 /* Check to see if the limit for messages per connection would be
4475 exceeded by accepting further messages. */
4477 if (smtp_accept_max_per_connection > 0 &&
4478 smtp_mailcmd_count > smtp_accept_max_per_connection)
4480 smtp_printf("421 too many messages in this connection\r\n", FALSE);
4481 log_write(0, LOG_MAIN|LOG_REJECT, "rejected MAIL command %s: too many "
4482 "messages in one connection", host_and_ident(TRUE));
4486 /* Reset for start of message - even if this is going to fail, we
4487 obviously need to throw away any previous data. */
4489 cancel_cutthrough_connection(TRUE, US"MAIL received");
4490 smtp_reset(reset_point);
4492 sender_data = recipient_data = NULL;
4494 /* Loop, checking for ESMTP additions to the MAIL FROM command. */
4498 uschar *name, *value, *end;
4499 unsigned long int size;
4500 BOOL arg_error = FALSE;
4502 if (!extract_option(&name, &value)) break;
4504 for (mail_args = env_mail_type_list;
4505 mail_args->value != ENV_MAIL_OPT_NULL;
4508 if (strcmpic(name, mail_args->name) == 0)
4510 if (mail_args->need_value && strcmpic(value, US"") == 0)
4513 switch(mail_args->value)
4515 /* Handle SIZE= by reading the value. We don't do the check till later,
4516 in order to be able to log the sender address on failure. */
4517 case ENV_MAIL_OPT_SIZE:
4518 if (((size = Ustrtoul(value, &end, 10)), *end == 0))
4520 if ((size == ULONG_MAX && errno == ERANGE) || size > INT_MAX)
4522 message_size = (int)size;
4528 /* If this session was initiated with EHLO and accept_8bitmime is set,
4529 Exim will have indicated that it supports the BODY=8BITMIME option. In
4530 fact, it does not support this according to the RFCs, in that it does not
4531 take any special action for forwarding messages containing 8-bit
4532 characters. That is why accept_8bitmime is not the default setting, but
4533 some sites want the action that is provided. We recognize both "8BITMIME"
4534 and "7BIT" as body types, but take no action. */
4535 case ENV_MAIL_OPT_BODY:
4536 if (accept_8bitmime) {
4537 if (strcmpic(value, US"8BITMIME") == 0)
4539 else if (strcmpic(value, US"7BIT") == 0)
4544 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4545 US"invalid data for BODY");
4548 DEBUG(D_receive) debug_printf("8BITMIME: %d\n", body_8bitmime);
4554 /* Handle the two DSN options, but only if configured to do so (which
4555 will have caused "DSN" to be given in the EHLO response). The code itself
4556 is included only if configured in at build time. */
4558 case ENV_MAIL_OPT_RET:
4561 /* Check if RET has already been set */
4564 synprot_error(L_smtp_syntax_error, 501, NULL,
4565 US"RET can be specified once only");
4568 dsn_ret = strcmpic(value, US"HDRS") == 0
4570 : strcmpic(value, US"FULL") == 0
4573 DEBUG(D_receive) debug_printf("DSN_RET: %d\n", dsn_ret);
4574 /* Check for invalid invalid value, and exit with error */
4577 synprot_error(L_smtp_syntax_error, 501, NULL,
4578 US"Value for RET is invalid");
4583 case ENV_MAIL_OPT_ENVID:
4586 /* Check if the dsn envid has been already set */
4587 if (dsn_envid != NULL)
4589 synprot_error(L_smtp_syntax_error, 501, NULL,
4590 US"ENVID can be specified once only");
4593 dsn_envid = string_copy(value);
4594 DEBUG(D_receive) debug_printf("DSN_ENVID: %s\n", dsn_envid);
4598 /* Handle the AUTH extension. If the value given is not "<>" and either
4599 the ACL says "yes" or there is no ACL but the sending host is
4600 authenticated, we set it up as the authenticated sender. However, if the
4601 authenticator set a condition to be tested, we ignore AUTH on MAIL unless
4602 the condition is met. The value of AUTH is an xtext, which means that +,
4603 = and cntrl chars are coded in hex; however "<>" is unaffected by this
4605 case ENV_MAIL_OPT_AUTH:
4606 if (Ustrcmp(value, "<>") != 0)
4611 if (auth_xtextdecode(value, &authenticated_sender) < 0)
4613 /* Put back terminator overrides for error message */
4616 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4617 US"invalid data for AUTH");
4620 if (!acl_smtp_mailauth)
4622 ignore_msg = US"client not authenticated";
4623 rc = sender_host_authenticated ? OK : FAIL;
4627 ignore_msg = US"rejected by ACL";
4628 rc = acl_check(ACL_WHERE_MAILAUTH, NULL, acl_smtp_mailauth,
4629 &user_msg, &log_msg);
4635 if (authenticated_by == NULL ||
4636 authenticated_by->mail_auth_condition == NULL ||
4637 expand_check_condition(authenticated_by->mail_auth_condition,
4638 authenticated_by->name, US"authenticator"))
4639 break; /* Accept the AUTH */
4641 ignore_msg = US"server_mail_auth_condition failed";
4642 if (authenticated_id != NULL)
4643 ignore_msg = string_sprintf("%s: authenticated ID=\"%s\"",
4644 ignore_msg, authenticated_id);
4649 authenticated_sender = NULL;
4650 log_write(0, LOG_MAIN, "ignoring AUTH=%s from %s (%s)",
4651 value, host_and_ident(TRUE), ignore_msg);
4654 /* Should only get DEFER or ERROR here. Put back terminator
4655 overrides for error message */
4660 (void)smtp_handle_acl_fail(ACL_WHERE_MAILAUTH, rc, user_msg,
4667 #ifndef DISABLE_PRDR
4668 case ENV_MAIL_OPT_PRDR:
4670 prdr_requested = TRUE;
4675 case ENV_MAIL_OPT_UTF8:
4676 if (smtputf8_advertised)
4678 int old_pool = store_pool;
4680 DEBUG(D_receive) debug_printf("smtputf8 requested\n");
4681 message_smtputf8 = allow_utf8_domains = TRUE;
4682 store_pool = POOL_PERM;
4683 received_protocol = string_sprintf("utf8%s", received_protocol);
4684 store_pool = old_pool;
4688 /* No valid option. Stick back the terminator characters and break
4689 the loop. Do the name-terminator second as extract_option sets
4690 value==name when it found no equal-sign.
4691 An error for a malformed address will occur. */
4692 case ENV_MAIL_OPT_NULL:
4700 /* Break out of for loop if switch() had bad argument or
4701 when start of the email address is reached */
4702 if (arg_error) break;
4705 /* If we have passed the threshold for rate limiting, apply the current
4706 delay, and update it for next time, provided this is a limited host. */
4708 if (smtp_mailcmd_count > smtp_rlm_threshold &&
4709 verify_check_host(&smtp_ratelimit_hosts) == OK)
4711 DEBUG(D_receive) debug_printf("rate limit MAIL: delay %.3g sec\n",
4712 smtp_delay_mail/1000.0);
4713 millisleep((int)smtp_delay_mail);
4714 smtp_delay_mail *= smtp_rlm_factor;
4715 if (smtp_delay_mail > (double)smtp_rlm_limit)
4716 smtp_delay_mail = (double)smtp_rlm_limit;
4719 /* Now extract the address, first applying any SMTP-time rewriting. The
4720 TRUE flag allows "<>" as a sender address. */
4722 raw_sender = rewrite_existflags & rewrite_smtp
4723 ? rewrite_one(smtp_cmd_data, rewrite_smtp, NULL, FALSE, US"",
4724 global_rewrite_rules)
4728 parse_extract_address(raw_sender, &errmess, &start, &end, &sender_domain,
4733 done = synprot_error(L_smtp_syntax_error, 501, smtp_cmd_data, errmess);
4737 sender_address = raw_sender;
4739 /* If there is a configured size limit for mail, check that this message
4740 doesn't exceed it. The check is postponed to this point so that the sender
4743 if (thismessage_size_limit > 0 && message_size > thismessage_size_limit)
4745 smtp_printf("552 Message size exceeds maximum permitted\r\n", FALSE);
4746 log_write(L_size_reject,
4747 LOG_MAIN|LOG_REJECT, "rejected MAIL FROM:<%s> %s: "
4748 "message too big: size%s=%d max=%d",
4750 host_and_ident(TRUE),
4751 (message_size == INT_MAX)? ">" : "",
4753 thismessage_size_limit);
4754 sender_address = NULL;
4758 /* Check there is enough space on the disk unless configured not to.
4759 When smtp_check_spool_space is set, the check is for thismessage_size_limit
4760 plus the current message - i.e. we accept the message only if it won't
4761 reduce the space below the threshold. Add 5000 to the size to allow for
4762 overheads such as the Received: line and storing of recipients, etc.
4763 By putting the check here, even when SIZE is not given, it allow VRFY
4764 and EXPN etc. to be used when space is short. */
4766 if (!receive_check_fs(
4767 (smtp_check_spool_space && message_size >= 0)?
4768 message_size + 5000 : 0))
4770 smtp_printf("452 Space shortage, please try later\r\n", FALSE);
4771 sender_address = NULL;
4775 /* If sender_address is unqualified, reject it, unless this is a locally
4776 generated message, or the sending host or net is permitted to send
4777 unqualified addresses - typically local machines behaving as MUAs -
4778 in which case just qualify the address. The flag is set above at the start
4779 of the SMTP connection. */
4781 if (sender_domain == 0 && sender_address[0] != 0)
4783 if (allow_unqualified_sender)
4785 sender_domain = Ustrlen(sender_address) + 1;
4786 sender_address = rewrite_address_qualify(sender_address, FALSE);
4787 DEBUG(D_receive) debug_printf("unqualified address %s accepted\n",
4792 smtp_printf("501 %s: sender address must contain a domain\r\n", FALSE,
4794 log_write(L_smtp_syntax_error,
4795 LOG_MAIN|LOG_REJECT,
4796 "unqualified sender rejected: <%s> %s%s",
4798 host_and_ident(TRUE),
4800 sender_address = NULL;
4805 /* Apply an ACL check if one is defined, before responding. Afterwards,
4806 when pipelining is not advertised, do another sync check in case the ACL
4807 delayed and the client started sending in the meantime. */
4811 rc = acl_check(ACL_WHERE_MAIL, NULL, acl_smtp_mail, &user_msg, &log_msg);
4812 if (rc == OK && !pipelining_advertised && !check_sync())
4818 if (rc == OK || rc == DISCARD)
4820 BOOL more = pipeline_response();
4823 smtp_printf("%s%s%s", more, US"250 OK",
4824 #ifndef DISABLE_PRDR
4825 prdr_requested ? US", PRDR Requested" : US"",
4832 #ifndef DISABLE_PRDR
4834 user_msg = string_sprintf("%s%s", user_msg, US", PRDR Requested");
4836 smtp_user_msg(US"250", user_msg);
4838 smtp_delay_rcpt = smtp_rlr_base;
4839 recipients_discarded = (rc == DISCARD);
4840 was_rej_mail = FALSE;
4844 done = smtp_handle_acl_fail(ACL_WHERE_MAIL, rc, user_msg, log_msg);
4845 sender_address = NULL;
4850 /* The RCPT command requires an address as an operand. There may be any
4851 number of RCPT commands, specifying multiple recipients. We build them all
4852 into a data structure. The start/end values given by parse_extract_address
4853 are not used, as we keep only the extracted address. */
4858 was_rcpt = rcpt_in_progress = TRUE;
4860 /* There must be a sender address; if the sender was rejected and
4861 pipelining was advertised, we assume the client was pipelining, and do not
4862 count this as a protocol error. Reset was_rej_mail so that further RCPTs
4863 get the same treatment. */
4865 if (sender_address == NULL)
4867 if (pipelining_advertised && last_was_rej_mail)
4869 smtp_printf("503 sender not yet given\r\n", FALSE);
4870 was_rej_mail = TRUE;
4874 done = synprot_error(L_smtp_protocol_error, 503, NULL,
4875 US"sender not yet given");
4876 was_rcpt = FALSE; /* Not a valid RCPT */
4882 /* Check for an operand */
4884 if (smtp_cmd_data[0] == 0)
4886 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4887 US"RCPT must have an address operand");
4892 /* Set the DSN flags orcpt and dsn_flags from the session*/
4898 uschar *name, *value;
4900 if (!extract_option(&name, &value))
4903 if (dsn_advertised && strcmpic(name, US"ORCPT") == 0)
4905 /* Check whether orcpt has been already set */
4908 synprot_error(L_smtp_syntax_error, 501, NULL,
4909 US"ORCPT can be specified once only");
4912 orcpt = string_copy(value);
4913 DEBUG(D_receive) debug_printf("DSN orcpt: %s\n", orcpt);
4916 else if (dsn_advertised && strcmpic(name, US"NOTIFY") == 0)
4918 /* Check if the notify flags have been already set */
4921 synprot_error(L_smtp_syntax_error, 501, NULL,
4922 US"NOTIFY can be specified once only");
4925 if (strcmpic(value, US"NEVER") == 0)
4926 flags |= rf_notify_never;
4933 while (*pp != 0 && *pp != ',') pp++;
4934 if (*pp == ',') *pp++ = 0;
4935 if (strcmpic(p, US"SUCCESS") == 0)
4937 DEBUG(D_receive) debug_printf("DSN: Setting notify success\n");
4938 flags |= rf_notify_success;
4940 else if (strcmpic(p, US"FAILURE") == 0)
4942 DEBUG(D_receive) debug_printf("DSN: Setting notify failure\n");
4943 flags |= rf_notify_failure;
4945 else if (strcmpic(p, US"DELAY") == 0)
4947 DEBUG(D_receive) debug_printf("DSN: Setting notify delay\n");
4948 flags |= rf_notify_delay;
4952 /* Catch any strange values */
4953 synprot_error(L_smtp_syntax_error, 501, NULL,
4954 US"Invalid value for NOTIFY parameter");
4959 DEBUG(D_receive) debug_printf("DSN Flags: %x\n", flags);
4963 /* Unknown option. Stick back the terminator characters and break
4964 the loop. An error for a malformed address will occur. */
4968 DEBUG(D_receive) debug_printf("Invalid RCPT option: %s : %s\n", name, value);
4975 /* Apply SMTP rewriting then extract the working address. Don't allow "<>"
4976 as a recipient address */
4978 recipient = rewrite_existflags & rewrite_smtp
4979 ? rewrite_one(smtp_cmd_data, rewrite_smtp, NULL, FALSE, US"",
4980 global_rewrite_rules)
4983 if (!(recipient = parse_extract_address(recipient, &errmess, &start, &end,
4984 &recipient_domain, FALSE)))
4986 done = synprot_error(L_smtp_syntax_error, 501, smtp_cmd_data, errmess);
4991 /* If the recipient address is unqualified, reject it, unless this is a
4992 locally generated message. However, unqualified addresses are permitted
4993 from a configured list of hosts and nets - typically when behaving as
4994 MUAs rather than MTAs. Sad that SMTP is used for both types of traffic,
4995 really. The flag is set at the start of the SMTP connection.
4997 RFC 1123 talks about supporting "the reserved mailbox postmaster"; I always
4998 assumed this meant "reserved local part", but the revision of RFC 821 and
4999 friends now makes it absolutely clear that it means *mailbox*. Consequently
5000 we must always qualify this address, regardless. */
5002 if (!recipient_domain)
5003 if (!(recipient_domain = qualify_recipient(&recipient, smtp_cmd_data,
5010 /* Check maximum allowed */
5012 if (rcpt_count > recipients_max && recipients_max > 0)
5014 if (recipients_max_reject)
5017 smtp_printf("552 too many recipients\r\n", FALSE);
5019 log_write(0, LOG_MAIN|LOG_REJECT, "too many recipients: message "
5020 "rejected: sender=<%s> %s", sender_address, host_and_ident(TRUE));
5025 smtp_printf("452 too many recipients\r\n", FALSE);
5027 log_write(0, LOG_MAIN|LOG_REJECT, "too many recipients: excess "
5028 "temporarily rejected: sender=<%s> %s", sender_address,
5029 host_and_ident(TRUE));
5036 /* If we have passed the threshold for rate limiting, apply the current
5037 delay, and update it for next time, provided this is a limited host. */
5039 if (rcpt_count > smtp_rlr_threshold &&
5040 verify_check_host(&smtp_ratelimit_hosts) == OK)
5042 DEBUG(D_receive) debug_printf("rate limit RCPT: delay %.3g sec\n",
5043 smtp_delay_rcpt/1000.0);
5044 millisleep((int)smtp_delay_rcpt);
5045 smtp_delay_rcpt *= smtp_rlr_factor;
5046 if (smtp_delay_rcpt > (double)smtp_rlr_limit)
5047 smtp_delay_rcpt = (double)smtp_rlr_limit;
5050 /* If the MAIL ACL discarded all the recipients, we bypass ACL checking
5051 for them. Otherwise, check the access control list for this recipient. As
5052 there may be a delay in this, re-check for a synchronization error
5053 afterwards, unless pipelining was advertised. */
5055 if (recipients_discarded)
5058 if ( (rc = acl_check(ACL_WHERE_RCPT, recipient, acl_smtp_rcpt, &user_msg,
5060 && !pipelining_advertised && !check_sync())
5063 /* The ACL was happy */
5067 BOOL more = pipeline_response();
5070 smtp_user_msg(US"250", user_msg);
5072 smtp_printf("250 Accepted\r\n", more);
5073 receive_add_recipient(recipient, -1);
5075 /* Set the dsn flags in the recipients_list */
5076 recipients_list[recipients_count-1].orcpt = orcpt;
5077 recipients_list[recipients_count-1].dsn_flags = flags;
5079 DEBUG(D_receive) debug_printf("DSN: orcpt: %s flags: %d\n",
5080 recipients_list[recipients_count-1].orcpt,
5081 recipients_list[recipients_count-1].dsn_flags);
5084 /* The recipient was discarded */
5086 else if (rc == DISCARD)
5089 smtp_user_msg(US"250", user_msg);
5091 smtp_printf("250 Accepted\r\n", FALSE);
5094 log_write(0, LOG_MAIN|LOG_REJECT, "%s F=<%s> RCPT %s: "
5095 "discarded by %s ACL%s%s", host_and_ident(TRUE),
5096 sender_address_unrewritten? sender_address_unrewritten : sender_address,
5097 smtp_cmd_argument, recipients_discarded? "MAIL" : "RCPT",
5098 log_msg ? US": " : US"", log_msg ? log_msg : US"");
5101 /* Either the ACL failed the address, or it was deferred. */
5105 if (rc == FAIL) rcpt_fail_count++; else rcpt_defer_count++;
5106 done = smtp_handle_acl_fail(ACL_WHERE_RCPT, rc, user_msg, log_msg);
5111 /* The DATA command is legal only if it follows successful MAIL FROM
5112 and RCPT TO commands. However, if pipelining is advertised, a bad DATA is
5113 not counted as a protocol error if it follows RCPT (which must have been
5114 rejected if there are no recipients.) This function is complete when a
5115 valid DATA command is encountered.
5117 Note concerning the code used: RFC 2821 says this:
5119 - If there was no MAIL, or no RCPT, command, or all such commands
5120 were rejected, the server MAY return a "command out of sequence"
5121 (503) or "no valid recipients" (554) reply in response to the
5124 The example in the pipelining RFC 2920 uses 554, but I use 503 here
5125 because it is the same whether pipelining is in use or not.
5127 If all the RCPT commands that precede DATA provoked the same error message
5128 (often indicating some kind of system error), it is helpful to include it
5129 with the DATA rejection (an idea suggested by Tony Finch). */
5136 if (chunking_state != CHUNKING_OFFERED)
5138 done = synprot_error(L_smtp_protocol_error, 503, NULL,
5139 US"BDAT command used when CHUNKING not advertised");
5143 /* grab size, endmarker */
5145 if (sscanf(CS smtp_cmd_data, "%u %n", &chunking_datasize, &n) < 1)
5147 done = synprot_error(L_smtp_protocol_error, 501, NULL,
5148 US"missing size for BDAT command");
5151 chunking_state = strcmpic(smtp_cmd_data+n, US"LAST") == 0
5152 ? CHUNKING_LAST : CHUNKING_ACTIVE;
5153 chunking_data_left = chunking_datasize;
5154 DEBUG(D_receive) debug_printf("chunking state %d, %d bytes\n",
5155 (int)chunking_state, chunking_data_left);
5157 /* push the current receive_* function on the "stack", and
5158 replace them by bdat_getc(), which in turn will use the lwr_receive_*
5159 functions to do the dirty work. */
5160 lwr_receive_getc = receive_getc;
5161 lwr_receive_getbuf = receive_getbuf;
5162 lwr_receive_ungetc = receive_ungetc;
5164 receive_getc = bdat_getc;
5165 receive_ungetc = bdat_ungetc;
5176 DATA_BDAT: /* Common code for DATA and BDAT */
5177 if (!discarded && recipients_count <= 0)
5179 if (rcpt_smtp_response_same && rcpt_smtp_response != NULL)
5181 uschar *code = US"503";
5182 int len = Ustrlen(rcpt_smtp_response);
5183 smtp_respond(code, 3, FALSE, US"All RCPT commands were rejected with "
5185 /* Responses from smtp_printf() will have \r\n on the end */
5186 if (len > 2 && rcpt_smtp_response[len-2] == '\r')
5187 rcpt_smtp_response[len-2] = 0;
5188 smtp_respond(code, 3, FALSE, rcpt_smtp_response);
5190 if (pipelining_advertised && last_was_rcpt)
5191 smtp_printf("503 Valid RCPT command must precede %s\r\n", FALSE,
5192 smtp_names[smtp_connection_had[smtp_ch_index-1]]);
5194 done = synprot_error(L_smtp_protocol_error, 503, NULL,
5195 smtp_connection_had[smtp_ch_index-1] == SCH_DATA
5196 ? US"valid RCPT command must precede DATA"
5197 : US"valid RCPT command must precede BDAT");
5199 if (chunking_state > CHUNKING_OFFERED)
5204 if (toomany && recipients_max_reject)
5206 sender_address = NULL; /* This will allow a new MAIL without RSET */
5207 sender_address_unrewritten = NULL;
5208 smtp_printf("554 Too many recipients\r\n", FALSE);
5212 if (chunking_state > CHUNKING_OFFERED)
5213 rc = OK; /* No predata ACL or go-ahead output for BDAT */
5216 /* If there is an ACL, re-check the synchronization afterwards, since the
5217 ACL may have delayed. To handle cutthrough delivery enforce a dummy call
5218 to get the DATA command sent. */
5220 if (acl_smtp_predata == NULL && cutthrough.fd < 0)
5224 uschar * acl = acl_smtp_predata ? acl_smtp_predata : US"accept";
5225 enable_dollar_recipients = TRUE;
5226 rc = acl_check(ACL_WHERE_PREDATA, NULL, acl, &user_msg,
5228 enable_dollar_recipients = FALSE;
5229 if (rc == OK && !check_sync())
5233 { /* Either the ACL failed the address, or it was deferred. */
5234 done = smtp_handle_acl_fail(ACL_WHERE_PREDATA, rc, user_msg, log_msg);
5240 smtp_user_msg(US"354", user_msg);
5243 "354 Enter message, ending with \".\" on a line by itself\r\n", FALSE);
5247 if (smtp_in) /* all ACKs needed to ramp window up for bulk data */
5248 (void) setsockopt(fileno(smtp_in), IPPROTO_TCP, TCP_QUICKACK,
5249 US &on, sizeof(on));
5252 message_ended = END_NOTENDED; /* Indicate in middle of data */
5263 if (!(address = parse_extract_address(smtp_cmd_data, &errmess,
5264 &start, &end, &recipient_domain, FALSE)))
5266 smtp_printf("501 %s\r\n", FALSE, errmess);
5270 if (!recipient_domain)
5271 if (!(recipient_domain = qualify_recipient(&address, smtp_cmd_data,
5275 if ((rc = acl_check(ACL_WHERE_VRFY, address, acl_smtp_vrfy,
5276 &user_msg, &log_msg)) != OK)
5277 done = smtp_handle_acl_fail(ACL_WHERE_VRFY, rc, user_msg, log_msg);
5281 address_item * addr = deliver_make_addr(address, FALSE);
5283 switch(verify_address(addr, NULL, vopt_is_recipient | vopt_qualify, -1,
5284 -1, -1, NULL, NULL, NULL))
5287 s = string_sprintf("250 <%s> is deliverable", address);
5291 s = (addr->user_message != NULL)?
5292 string_sprintf("451 <%s> %s", address, addr->user_message) :
5293 string_sprintf("451 Cannot resolve <%s> at this time", address);
5297 s = (addr->user_message != NULL)?
5298 string_sprintf("550 <%s> %s", address, addr->user_message) :
5299 string_sprintf("550 <%s> is not deliverable", address);
5300 log_write(0, LOG_MAIN, "VRFY failed for %s %s",
5301 smtp_cmd_argument, host_and_ident(TRUE));
5305 smtp_printf("%s\r\n", FALSE, s);
5313 rc = acl_check(ACL_WHERE_EXPN, NULL, acl_smtp_expn, &user_msg, &log_msg);
5315 done = smtp_handle_acl_fail(ACL_WHERE_EXPN, rc, user_msg, log_msg);
5318 BOOL save_log_testing_mode = log_testing_mode;
5319 address_test_mode = log_testing_mode = TRUE;
5320 (void) verify_address(deliver_make_addr(smtp_cmd_data, FALSE),
5321 smtp_out, vopt_is_recipient | vopt_qualify | vopt_expn, -1, -1, -1,
5323 address_test_mode = FALSE;
5324 log_testing_mode = save_log_testing_mode; /* true for -bh */
5333 if (!tls_advertised)
5335 done = synprot_error(L_smtp_protocol_error, 503, NULL,
5336 US"STARTTLS command used when not advertised");
5340 /* Apply an ACL check if one is defined */
5342 if ( acl_smtp_starttls
5343 && (rc = acl_check(ACL_WHERE_STARTTLS, NULL, acl_smtp_starttls,
5344 &user_msg, &log_msg)) != OK
5347 done = smtp_handle_acl_fail(ACL_WHERE_STARTTLS, rc, user_msg, log_msg);
5351 /* RFC 2487 is not clear on when this command may be sent, though it
5352 does state that all information previously obtained from the client
5353 must be discarded if a TLS session is started. It seems reasonable to
5354 do an implied RSET when STARTTLS is received. */
5356 incomplete_transaction_log(US"STARTTLS");
5357 cancel_cutthrough_connection(TRUE, US"STARTTLS received");
5358 smtp_reset(reset_point);
5360 cmd_list[CMD_LIST_STARTTLS].is_mail_cmd = FALSE;
5362 /* There's an attack where more data is read in past the STARTTLS command
5363 before TLS is negotiated, then assumed to be part of the secure session
5364 when used afterwards; we use segregated input buffers, so are not
5365 vulnerable, but we want to note when it happens and, for sheer paranoia,
5366 ensure that the buffer is "wiped".
5367 Pipelining sync checks will normally have protected us too, unless disabled
5368 by configuration. */
5370 if (receive_smtp_buffered())
5373 debug_printf("Non-empty input buffer after STARTTLS; naive attack?\n");
5374 if (tls_in.active < 0)
5375 smtp_inend = smtp_inptr = smtp_inbuffer;
5376 /* and if TLS is already active, tls_server_start() should fail */
5379 /* There is nothing we value in the input buffer and if TLS is successfully
5380 negotiated, we won't use this buffer again; if TLS fails, we'll just read
5381 fresh content into it. The buffer contains arbitrary content from an
5382 untrusted remote source; eg: NOOP <shellcode>\r\nSTARTTLS\r\n
5383 It seems safest to just wipe away the content rather than leave it as a
5384 target to jump to. */
5386 memset(smtp_inbuffer, 0, IN_BUFFER_SIZE);
5388 /* Attempt to start up a TLS session, and if successful, discard all
5389 knowledge that was obtained previously. At least, that's what the RFC says,
5390 and that's what happens by default. However, in order to work round YAEB,
5391 there is an option to remember the esmtp state. Sigh.
5393 We must allow for an extra EHLO command and an extra AUTH command after
5394 STARTTLS that don't add to the nonmail command count. */
5397 if ((rc = tls_server_start(tls_require_ciphers, &s)) == OK)
5399 if (!tls_remember_esmtp)
5400 helo_seen = esmtp = auth_advertised = pipelining_advertised = FALSE;
5401 cmd_list[CMD_LIST_EHLO].is_mail_cmd = TRUE;
5402 cmd_list[CMD_LIST_AUTH].is_mail_cmd = TRUE;
5403 cmd_list[CMD_LIST_TLS_AUTH].is_mail_cmd = TRUE;
5404 if (sender_helo_name)
5406 store_free(sender_helo_name);
5407 sender_helo_name = NULL;
5408 host_build_sender_fullhost(); /* Rebuild */
5409 set_process_info("handling incoming TLS connection from %s",
5410 host_and_ident(FALSE));
5413 (sender_host_address ? protocols : protocols_local)
5415 ? pextend + (sender_host_authenticated ? pauthed : 0)
5417 + (tls_in.active >= 0 ? pcrpted : 0)
5420 sender_host_auth_pubname = sender_host_authenticated = NULL;
5421 authenticated_id = NULL;
5422 sync_cmd_limit = NON_SYNC_CMD_NON_PIPELINING;
5423 DEBUG(D_tls) debug_printf("TLS active\n");
5424 break; /* Successful STARTTLS */
5427 (void) smtp_log_tls_fail(s);
5429 /* Some local configuration problem was discovered before actually trying
5430 to do a TLS handshake; give a temporary error. */
5434 smtp_printf("454 TLS currently unavailable\r\n", FALSE);
5438 /* Hard failure. Reject everything except QUIT or closed connection. One
5439 cause for failure is a nested STARTTLS, in which case tls_in.active remains
5440 set, but we must still reject all incoming commands. */
5442 DEBUG(D_tls) debug_printf("TLS failed to start\n");
5443 while (done <= 0) switch(smtp_read_command(FALSE, GETC_BUFFER_UNLIMITED))
5446 log_write(L_smtp_connection, LOG_MAIN, "%s closed by EOF",
5447 smtp_get_connection_info());
5448 smtp_notquit_exit(US"tls-failed", NULL, NULL);
5452 /* It is perhaps arguable as to which exit ACL should be called here,
5453 but as it is probably a situation that almost never arises, it
5454 probably doesn't matter. We choose to call the real QUIT ACL, which in
5455 some sense is perhaps "right". */
5460 && ((rc = acl_check(ACL_WHERE_QUIT, NULL, acl_smtp_quit, &user_msg,
5461 &log_msg)) == ERROR))
5462 log_write(0, LOG_MAIN|LOG_PANIC, "ACL for QUIT returned ERROR: %s",
5465 smtp_respond(US"221", 3, TRUE, user_msg);
5467 smtp_printf("221 %s closing connection\r\n", FALSE, smtp_active_hostname);
5468 log_write(L_smtp_connection, LOG_MAIN, "%s closed by QUIT",
5469 smtp_get_connection_info());
5474 smtp_printf("554 Security failure\r\n", FALSE);
5477 tls_close(TRUE, TLS_SHUTDOWN_NOWAIT);
5482 /* The ACL for QUIT is provided for gathering statistical information or
5483 similar; it does not affect the response code, but it can supply a custom
5487 smtp_quit_handler(&user_msg, &log_msg);
5493 smtp_rset_handler();
5494 cancel_cutthrough_connection(TRUE, US"RSET received");
5495 smtp_reset(reset_point);
5502 smtp_printf("250 OK\r\n", FALSE);
5506 /* Show ETRN/EXPN/VRFY if there's an ACL for checking hosts; if actually
5507 used, a check will be done for permitted hosts. Show STARTTLS only if not
5508 already in a TLS session and if it would be advertised in the EHLO
5513 smtp_printf("214-Commands supported:\r\n", TRUE);
5517 Ustrcat(buffer, " AUTH");
5519 if (tls_in.active < 0 &&
5520 verify_check_host(&tls_advertise_hosts) != FAIL)
5521 Ustrcat(buffer, " STARTTLS");
5523 Ustrcat(buffer, " HELO EHLO MAIL RCPT DATA BDAT");
5524 Ustrcat(buffer, " NOOP QUIT RSET HELP");
5525 if (acl_smtp_etrn != NULL) Ustrcat(buffer, " ETRN");
5526 if (acl_smtp_expn != NULL) Ustrcat(buffer, " EXPN");
5527 if (acl_smtp_vrfy != NULL) Ustrcat(buffer, " VRFY");
5528 smtp_printf("214%s\r\n", FALSE, buffer);
5534 incomplete_transaction_log(US"connection lost");
5535 smtp_notquit_exit(US"connection-lost", US"421",
5536 US"%s lost input connection", smtp_active_hostname);
5538 /* Don't log by default unless in the middle of a message, as some mailers
5539 just drop the call rather than sending QUIT, and it clutters up the logs.
5542 if (sender_address || recipients_count > 0)
5543 log_write(L_lost_incoming_connection, LOG_MAIN,
5544 "unexpected %s while reading SMTP command from %s%s%s D=%s",
5545 sender_host_unknown ? "EOF" : "disconnection",
5546 tcp_in_fastopen && !tcp_in_fastopen_logged ? US"TFO " : US"",
5547 host_and_ident(FALSE), smtp_read_error,
5548 string_timesince(&smtp_connection_start)
5552 log_write(L_smtp_connection, LOG_MAIN, "%s %slost%s D=%s",
5553 smtp_get_connection_info(),
5554 tcp_in_fastopen && !tcp_in_fastopen_logged ? US"TFO " : US"",
5556 string_timesince(&smtp_connection_start)
5567 done = synprot_error(L_smtp_protocol_error, 503, NULL,
5568 US"ETRN is not permitted inside a transaction");
5572 log_write(L_etrn, LOG_MAIN, "ETRN %s received from %s", smtp_cmd_argument,
5573 host_and_ident(FALSE));
5575 if ((rc = acl_check(ACL_WHERE_ETRN, NULL, acl_smtp_etrn,
5576 &user_msg, &log_msg)) != OK)
5578 done = smtp_handle_acl_fail(ACL_WHERE_ETRN, rc, user_msg, log_msg);
5582 /* Compute the serialization key for this command. */
5584 etrn_serialize_key = string_sprintf("etrn-%s\n", smtp_cmd_data);
5586 /* If a command has been specified for running as a result of ETRN, we
5587 permit any argument to ETRN. If not, only the # standard form is permitted,
5588 since that is strictly the only kind of ETRN that can be implemented
5589 according to the RFC. */
5591 if (smtp_etrn_command)
5595 etrn_command = smtp_etrn_command;
5596 deliver_domain = smtp_cmd_data;
5597 rc = transport_set_up_command(&argv, smtp_etrn_command, TRUE, 0, NULL,
5598 US"ETRN processing", &error);
5599 deliver_domain = NULL;
5602 log_write(0, LOG_MAIN|LOG_PANIC, "failed to set up ETRN command: %s",
5604 smtp_printf("458 Internal failure\r\n", FALSE);
5609 /* Else set up to call Exim with the -R option. */
5613 if (*smtp_cmd_data++ != '#')
5615 done = synprot_error(L_smtp_syntax_error, 501, NULL,
5616 US"argument must begin with #");
5619 etrn_command = US"exim -R";
5620 argv = CUSS child_exec_exim(CEE_RETURN_ARGV, TRUE, NULL, TRUE,
5621 *queue_name ? 4 : 2,
5622 US"-R", smtp_cmd_data,
5623 US"-MCG", queue_name);
5626 /* If we are host-testing, don't actually do anything. */
5632 debug_printf("ETRN command is: %s\n", etrn_command);
5633 debug_printf("ETRN command execution skipped\n");
5635 if (user_msg == NULL) smtp_printf("250 OK\r\n", FALSE);
5636 else smtp_user_msg(US"250", user_msg);
5641 /* If ETRN queue runs are to be serialized, check the database to
5642 ensure one isn't already running. */
5644 if (smtp_etrn_serialize && !enq_start(etrn_serialize_key, 1))
5646 smtp_printf("458 Already processing %s\r\n", FALSE, smtp_cmd_data);
5650 /* Fork a child process and run the command. We don't want to have to
5651 wait for the process at any point, so set SIGCHLD to SIG_IGN before
5652 forking. It should be set that way anyway for external incoming SMTP,
5653 but we save and restore to be tidy. If serialization is required, we
5654 actually run the command in yet another process, so we can wait for it
5655 to complete and then remove the serialization lock. */
5657 oldsignal = signal(SIGCHLD, SIG_IGN);
5659 if ((pid = fork()) == 0)
5661 smtp_input = FALSE; /* This process is not associated with the */
5662 (void)fclose(smtp_in); /* SMTP call any more. */
5663 (void)fclose(smtp_out);
5665 signal(SIGCHLD, SIG_DFL); /* Want to catch child */
5667 /* If not serializing, do the exec right away. Otherwise, fork down
5668 into another process. */
5670 if (!smtp_etrn_serialize || (pid = fork()) == 0)
5672 DEBUG(D_exec) debug_print_argv(argv);
5673 exim_nullstd(); /* Ensure std{in,out,err} exist */
5674 execv(CS argv[0], (char *const *)argv);
5675 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "exec of \"%s\" (ETRN) failed: %s",
5676 etrn_command, strerror(errno));
5677 _exit(EXIT_FAILURE); /* paranoia */
5680 /* Obey this if smtp_serialize and the 2nd fork yielded non-zero. That
5681 is, we are in the first subprocess, after forking again. All we can do
5682 for a failing fork is to log it. Otherwise, wait for the 2nd process to
5683 complete, before removing the serialization. */
5686 log_write(0, LOG_MAIN|LOG_PANIC, "2nd fork for serialized ETRN "
5687 "failed: %s", strerror(errno));
5691 DEBUG(D_any) debug_printf("waiting for serialized ETRN process %d\n",
5693 (void)wait(&status);
5694 DEBUG(D_any) debug_printf("serialized ETRN process %d ended\n",
5698 enq_end(etrn_serialize_key);
5699 _exit(EXIT_SUCCESS);
5702 /* Back in the top level SMTP process. Check that we started a subprocess
5703 and restore the signal state. */
5707 log_write(0, LOG_MAIN|LOG_PANIC, "fork of process for ETRN failed: %s",
5709 smtp_printf("458 Unable to fork process\r\n", FALSE);
5710 if (smtp_etrn_serialize) enq_end(etrn_serialize_key);
5714 if (user_msg == NULL) smtp_printf("250 OK\r\n", FALSE);
5715 else smtp_user_msg(US"250", user_msg);
5718 signal(SIGCHLD, oldsignal);
5723 done = synprot_error(L_smtp_syntax_error, 501, NULL,
5724 US"unexpected argument data");
5728 /* This currently happens only for NULLs, but could be extended. */
5731 done = synprot_error(L_smtp_syntax_error, 0, NULL, /* Just logs */
5732 US"NUL character(s) present (shown as '?')");
5733 smtp_printf("501 NUL characters are not allowed in SMTP commands\r\n", FALSE);
5739 if (smtp_inend >= smtp_inbuffer + IN_BUFFER_SIZE)
5740 smtp_inend = smtp_inbuffer + IN_BUFFER_SIZE - 1;
5741 c = smtp_inend - smtp_inptr;
5742 if (c > 150) c = 150; /* limit logged amount */
5744 incomplete_transaction_log(US"sync failure");
5745 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP protocol synchronization error "
5746 "(next input sent too soon: pipelining was%s advertised): "
5747 "rejected \"%s\" %s next input=\"%s\"",
5748 pipelining_advertised? "" : " not",
5749 smtp_cmd_buffer, host_and_ident(TRUE),
5750 string_printing(smtp_inptr));
5751 smtp_notquit_exit(US"synchronization-error", US"554",
5752 US"SMTP synchronization error");
5753 done = 1; /* Pretend eof - drops connection */
5757 case TOO_MANY_NONMAIL_CMD:
5758 s = smtp_cmd_buffer;
5759 while (*s != 0 && !isspace(*s)) s++;
5760 incomplete_transaction_log(US"too many non-mail commands");
5761 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
5762 "nonmail commands (last was \"%.*s\")", host_and_ident(FALSE),
5763 (int)(s - smtp_cmd_buffer), smtp_cmd_buffer);
5764 smtp_notquit_exit(US"bad-commands", US"554", US"Too many nonmail commands");
5765 done = 1; /* Pretend eof - drops connection */
5768 #ifdef SUPPORT_PROXY
5769 case PROXY_FAIL_IGNORE_CMD:
5770 smtp_printf("503 Command refused, required Proxy negotiation failed\r\n", FALSE);
5775 if (unknown_command_count++ >= smtp_max_unknown_commands)
5777 log_write(L_smtp_syntax_error, LOG_MAIN,
5778 "SMTP syntax error in \"%s\" %s %s",
5779 string_printing(smtp_cmd_buffer), host_and_ident(TRUE),
5780 US"unrecognized command");
5781 incomplete_transaction_log(US"unrecognized command");
5782 smtp_notquit_exit(US"bad-commands", US"500",
5783 US"Too many unrecognized commands");
5785 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
5786 "unrecognized commands (last was \"%s\")", host_and_ident(FALSE),
5787 string_printing(smtp_cmd_buffer));
5790 done = synprot_error(L_smtp_syntax_error, 500, NULL,
5791 US"unrecognized command");
5795 /* This label is used by goto's inside loops that want to break out to
5796 the end of the command-processing loop. */
5799 last_was_rej_mail = was_rej_mail; /* Remember some last commands for */
5800 last_was_rcpt = was_rcpt; /* protocol error handling */
5804 return done - 2; /* Convert yield values */
5810 authres_smtpauth(gstring * g)
5812 if (!sender_host_authenticated)
5815 g = string_append(g, 2, US";\n\tauth=pass (", sender_host_auth_pubname);
5817 if (Ustrcmp(sender_host_auth_pubname, "tls") != 0)
5818 g = string_append(g, 2, US") smtp.auth=", authenticated_id);
5819 else if (authenticated_id)
5820 g = string_append(g, 2, US") x509.auth=", authenticated_id);
5822 g = string_catn(g, US") reason=x509.auth", 17);
5824 if (authenticated_sender)
5825 g = string_append(g, 2, US" smtp.mailfrom=", authenticated_sender);
5833 /* End of smtp_in.c */