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;
2055 #ifdef EXPERIMENTAL_DMARC
2056 dmarc_has_been_checked = dmarc_disable_verify = dmarc_enable_forensic = FALSE;
2057 dmarc_ar_header = dmarc_domain_policy = dmarc_forensic_sender =
2058 dmarc_history_file = dmarc_status = dmarc_status_text = dmarc_tld_file =
2059 dmarc_used_domain = NULL;
2063 deliver_host = deliver_host_address = NULL; /* Can be set by ACL */
2064 #ifndef DISABLE_PRDR
2065 prdr_requested = FALSE;
2068 spf_header_comment = spf_received = spf_result = spf_smtp_comment = NULL;
2069 spf_result_guessed = FALSE;
2071 #ifdef EXPERIMENTAL_DMARC
2072 dmarc_has_been_checked = dmarc_disable_verify = dmarc_enable_forensic = FALSE;
2073 dmarc_domain_policy = dmarc_status = dmarc_status_text = dmarc_used_domain = NULL;
2075 #ifdef EXPERIMENTAL_ARC
2076 arc_state = arc_state_reason = NULL;
2079 message_smtputf8 = FALSE;
2081 body_linecount = body_zerocount = 0;
2083 sender_rate = sender_rate_limit = sender_rate_period = NULL;
2084 ratelimiters_mail = NULL; /* Updated by ratelimit ACL condition */
2085 /* Note that ratelimiters_conn persists across resets. */
2087 /* Reset message ACL variables */
2091 /* The message body variables use malloc store. They may be set if this is
2092 not the first message in an SMTP session and the previous message caused them
2093 to be referenced in an ACL. */
2097 store_free(message_body);
2098 message_body = NULL;
2101 if (message_body_end)
2103 store_free(message_body_end);
2104 message_body_end = NULL;
2107 /* Warning log messages are also saved in malloc store. They are saved to avoid
2108 repetition in the same message, but it seems right to repeat them for different
2111 while (acl_warn_logged)
2113 string_item *this = acl_warn_logged;
2114 acl_warn_logged = acl_warn_logged->next;
2117 store_reset(reset_point);
2124 /*************************************************
2125 * Initialize for incoming batched SMTP message *
2126 *************************************************/
2128 /* This function is called from smtp_setup_msg() in the case when
2129 smtp_batched_input is true. This happens when -bS is used to pass a whole batch
2130 of messages in one file with SMTP commands between them. All errors must be
2131 reported by sending a message, and only MAIL FROM, RCPT TO, and DATA are
2132 relevant. After an error on a sender, or an invalid recipient, the remainder
2133 of the message is skipped. The value of received_protocol is already set.
2136 Returns: > 0 message successfully started (reached DATA)
2137 = 0 QUIT read or end of file reached
2138 < 0 should not occur
2142 smtp_setup_batch_msg(void)
2145 void *reset_point = store_get(0);
2147 /* Save the line count at the start of each transaction - single commands
2148 like HELO and RSET count as whole transactions. */
2150 bsmtp_transaction_linecount = receive_linecount;
2152 if ((receive_feof)()) return 0; /* Treat EOF as QUIT */
2154 cancel_cutthrough_connection(TRUE, US"smtp_setup_batch_msg");
2155 smtp_reset(reset_point); /* Reset for start of message */
2157 /* Deal with SMTP commands. This loop is exited by setting done to a POSITIVE
2158 value. The values are 2 larger than the required yield of the function. */
2163 uschar *recipient = NULL;
2164 int start, end, sender_domain, recipient_domain;
2166 switch(smtp_read_command(FALSE, GETC_BUFFER_UNLIMITED))
2168 /* The HELO/EHLO commands set sender_address_helo if they have
2169 valid data; otherwise they are ignored, except that they do
2170 a reset of the state. */
2175 check_helo(smtp_cmd_data);
2179 cancel_cutthrough_connection(TRUE, US"RSET received");
2180 smtp_reset(reset_point);
2181 bsmtp_transaction_linecount = receive_linecount;
2185 /* The MAIL FROM command requires an address as an operand. All we
2186 do here is to parse it for syntactic correctness. The form "<>" is
2187 a special case which converts into an empty string. The start/end
2188 pointers in the original are not used further for this address, as
2189 it is the canonical extracted address which is all that is kept. */
2192 smtp_mailcmd_count++; /* Count for no-mail log */
2193 if (sender_address != NULL)
2194 /* The function moan_smtp_batch() does not return. */
2195 moan_smtp_batch(smtp_cmd_buffer, "503 Sender already given");
2197 if (smtp_cmd_data[0] == 0)
2198 /* The function moan_smtp_batch() does not return. */
2199 moan_smtp_batch(smtp_cmd_buffer, "501 MAIL FROM must have an address operand");
2201 /* Reset to start of message */
2203 cancel_cutthrough_connection(TRUE, US"MAIL received");
2204 smtp_reset(reset_point);
2206 /* Apply SMTP rewrite */
2208 raw_sender = ((rewrite_existflags & rewrite_smtp) != 0)?
2209 rewrite_one(smtp_cmd_data, rewrite_smtp|rewrite_smtp_sender, NULL, FALSE,
2210 US"", global_rewrite_rules) : smtp_cmd_data;
2212 /* Extract the address; the TRUE flag allows <> as valid */
2215 parse_extract_address(raw_sender, &errmess, &start, &end, &sender_domain,
2219 /* The function moan_smtp_batch() does not return. */
2220 moan_smtp_batch(smtp_cmd_buffer, "501 %s", errmess);
2222 sender_address = string_copy(raw_sender);
2224 /* Qualify unqualified sender addresses if permitted to do so. */
2227 && sender_address[0] != 0 && sender_address[0] != '@')
2228 if (allow_unqualified_sender)
2230 sender_address = rewrite_address_qualify(sender_address, FALSE);
2231 DEBUG(D_receive) debug_printf("unqualified address %s accepted "
2232 "and rewritten\n", raw_sender);
2234 /* The function moan_smtp_batch() does not return. */
2236 moan_smtp_batch(smtp_cmd_buffer, "501 sender address must contain "
2241 /* The RCPT TO command requires an address as an operand. All we do
2242 here is to parse it for syntactic correctness. There may be any number
2243 of RCPT TO commands, specifying multiple senders. We build them all into
2244 a data structure that is in argc/argv format. The start/end values
2245 given by parse_extract_address are not used, as we keep only the
2246 extracted address. */
2249 if (!sender_address)
2250 /* The function moan_smtp_batch() does not return. */
2251 moan_smtp_batch(smtp_cmd_buffer, "503 No sender yet given");
2253 if (smtp_cmd_data[0] == 0)
2254 /* The function moan_smtp_batch() does not return. */
2255 moan_smtp_batch(smtp_cmd_buffer,
2256 "501 RCPT TO must have an address operand");
2258 /* Check maximum number allowed */
2260 if (recipients_max > 0 && recipients_count + 1 > recipients_max)
2261 /* The function moan_smtp_batch() does not return. */
2262 moan_smtp_batch(smtp_cmd_buffer, "%s too many recipients",
2263 recipients_max_reject? "552": "452");
2265 /* Apply SMTP rewrite, then extract address. Don't allow "<>" as a
2266 recipient address */
2268 recipient = rewrite_existflags & rewrite_smtp
2269 ? rewrite_one(smtp_cmd_data, rewrite_smtp, NULL, FALSE, US"",
2270 global_rewrite_rules)
2273 recipient = parse_extract_address(recipient, &errmess, &start, &end,
2274 &recipient_domain, FALSE);
2277 /* The function moan_smtp_batch() does not return. */
2278 moan_smtp_batch(smtp_cmd_buffer, "501 %s", errmess);
2280 /* If the recipient address is unqualified, qualify it if permitted. Then
2281 add it to the list of recipients. */
2283 if (!recipient_domain)
2284 if (allow_unqualified_recipient)
2286 DEBUG(D_receive) debug_printf("unqualified address %s accepted\n",
2288 recipient = rewrite_address_qualify(recipient, TRUE);
2290 /* The function moan_smtp_batch() does not return. */
2292 moan_smtp_batch(smtp_cmd_buffer,
2293 "501 recipient address must contain a domain");
2295 receive_add_recipient(recipient, -1);
2299 /* The DATA command is legal only if it follows successful MAIL FROM
2300 and RCPT TO commands. This function is complete when a valid DATA
2301 command is encountered. */
2304 if (!sender_address || recipients_count <= 0)
2305 /* The function moan_smtp_batch() does not return. */
2306 if (!sender_address)
2307 moan_smtp_batch(smtp_cmd_buffer,
2308 "503 MAIL FROM:<sender> command must precede DATA");
2310 moan_smtp_batch(smtp_cmd_buffer,
2311 "503 RCPT TO:<recipient> must precede DATA");
2314 done = 3; /* DATA successfully achieved */
2315 message_ended = END_NOTENDED; /* Indicate in middle of message */
2320 /* The VRFY, EXPN, HELP, ETRN, and NOOP commands are ignored. */
2327 bsmtp_transaction_linecount = receive_linecount;
2338 /* The function moan_smtp_batch() does not return. */
2339 moan_smtp_batch(smtp_cmd_buffer, "501 Unexpected argument data");
2344 /* The function moan_smtp_batch() does not return. */
2345 moan_smtp_batch(smtp_cmd_buffer, "501 Unexpected NULL in SMTP command");
2350 /* The function moan_smtp_batch() does not return. */
2351 moan_smtp_batch(smtp_cmd_buffer, "500 Command unrecognized");
2356 return done - 2; /* Convert yield values */
2363 smtp_log_tls_fail(uschar * errstr)
2365 uschar * conn_info = smtp_get_connection_info();
2367 if (Ustrncmp(conn_info, US"SMTP ", 5) == 0) conn_info += 5;
2368 /* I'd like to get separated H= here, but too hard for now */
2370 log_write(0, LOG_MAIN, "TLS error on %s %s", conn_info, errstr);
2382 struct tcp_info tinfo;
2383 socklen_t len = sizeof(tinfo);
2385 if ( getsockopt(fileno(smtp_out), IPPROTO_TCP, TCP_INFO, &tinfo, &len) == 0
2386 && tinfo.tcpi_state == TCP_SYN_RECV
2389 DEBUG(D_receive) debug_printf("TCP_FASTOPEN mode connection (state TCP_SYN_RECV)\n");
2390 tcp_in_fastopen = TRUE;
2397 /*************************************************
2398 * Start an SMTP session *
2399 *************************************************/
2401 /* This function is called at the start of an SMTP session. Thereafter,
2402 smtp_setup_msg() is called to initiate each separate message. This
2403 function does host-specific testing, and outputs the banner line.
2406 Returns: FALSE if the session can not continue; something has
2407 gone wrong, or the connection to the host is blocked
2411 smtp_start_session(void)
2414 uschar *user_msg, *log_msg;
2419 gettimeofday(&smtp_connection_start, NULL);
2420 for (smtp_ch_index = 0; smtp_ch_index < SMTP_HBUFF_SIZE; smtp_ch_index++)
2421 smtp_connection_had[smtp_ch_index] = SCH_NONE;
2424 /* Default values for certain variables */
2426 helo_seen = esmtp = helo_accept_junk = FALSE;
2427 smtp_mailcmd_count = 0;
2428 count_nonmail = TRUE_UNSET;
2429 synprot_error_count = unknown_command_count = nonmail_command_count = 0;
2430 smtp_delay_mail = smtp_rlm_base;
2431 auth_advertised = FALSE;
2432 pipelining_advertised = FALSE;
2433 pipelining_enable = TRUE;
2434 sync_cmd_limit = NON_SYNC_CMD_NON_PIPELINING;
2435 smtp_exit_function_called = FALSE; /* For avoiding loop in not-quit exit */
2437 /* If receiving by -bs from a trusted user, or testing with -bh, we allow
2438 authentication settings from -oMaa to remain in force. */
2440 if (!host_checking && !sender_host_notsocket)
2441 sender_host_auth_pubname = sender_host_authenticated = NULL;
2442 authenticated_by = NULL;
2445 tls_in.cipher = tls_in.peerdn = NULL;
2446 tls_in.ourcert = tls_in.peercert = NULL;
2448 tls_in.ocsp = OCSP_NOT_REQ;
2449 tls_advertised = FALSE;
2451 dsn_advertised = FALSE;
2453 smtputf8_advertised = FALSE;
2456 /* Reset ACL connection variables */
2460 /* Allow for trailing 0 in the command and data buffers. */
2462 if (!(smtp_cmd_buffer = US malloc(2*SMTP_CMD_BUFFER_SIZE + 2)))
2463 log_write(0, LOG_MAIN|LOG_PANIC_DIE,
2464 "malloc() failed for SMTP command buffer");
2466 smtp_cmd_buffer[0] = 0;
2467 smtp_data_buffer = smtp_cmd_buffer + SMTP_CMD_BUFFER_SIZE + 1;
2469 /* For batched input, the protocol setting can be overridden from the
2470 command line by a trusted caller. */
2472 if (smtp_batched_input)
2474 if (!received_protocol) received_protocol = US"local-bsmtp";
2477 /* For non-batched SMTP input, the protocol setting is forced here. It will be
2478 reset later if any of EHLO/AUTH/STARTTLS are received. */
2482 (sender_host_address ? protocols : protocols_local) [pnormal];
2484 /* Set up the buffer for inputting using direct read() calls, and arrange to
2485 call the local functions instead of the standard C ones. Place a NUL at the
2486 end of the buffer to safety-stop C-string reads from it. */
2488 if (!(smtp_inbuffer = US malloc(IN_BUFFER_SIZE)))
2489 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "malloc() failed for SMTP input buffer");
2490 smtp_inbuffer[IN_BUFFER_SIZE-1] = '\0';
2492 receive_getc = smtp_getc;
2493 receive_getbuf = smtp_getbuf;
2494 receive_get_cache = smtp_get_cache;
2495 receive_ungetc = smtp_ungetc;
2496 receive_feof = smtp_feof;
2497 receive_ferror = smtp_ferror;
2498 receive_smtp_buffered = smtp_buffered;
2499 smtp_inptr = smtp_inend = smtp_inbuffer;
2500 smtp_had_eof = smtp_had_error = 0;
2502 /* Set up the message size limit; this may be host-specific */
2504 thismessage_size_limit = expand_string_integer(message_size_limit, TRUE);
2505 if (expand_string_message)
2507 if (thismessage_size_limit == -1)
2508 log_write(0, LOG_MAIN|LOG_PANIC, "unable to expand message_size_limit: "
2509 "%s", expand_string_message);
2511 log_write(0, LOG_MAIN|LOG_PANIC, "invalid message_size_limit: "
2512 "%s", expand_string_message);
2513 smtp_closedown(US"Temporary local problem - please try later");
2517 /* When a message is input locally via the -bs or -bS options, sender_host_
2518 unknown is set unless -oMa was used to force an IP address, in which case it
2519 is checked like a real remote connection. When -bs is used from inetd, this
2520 flag is not set, causing the sending host to be checked. The code that deals
2521 with IP source routing (if configured) is never required for -bs or -bS and
2522 the flag sender_host_notsocket is used to suppress it.
2524 If smtp_accept_max and smtp_accept_reserve are set, keep some connections in
2525 reserve for certain hosts and/or networks. */
2527 if (!sender_host_unknown)
2530 BOOL reserved_host = FALSE;
2532 /* Look up IP options (source routing info) on the socket if this is not an
2533 -oMa "host", and if any are found, log them and drop the connection.
2535 Linux (and others now, see below) is different to everyone else, so there
2536 has to be some conditional compilation here. Versions of Linux before 2.1.15
2537 used a structure whose name was "options". Somebody finally realized that
2538 this name was silly, and it got changed to "ip_options". I use the
2539 newer name here, but there is a fudge in the script that sets up os.h
2540 to define a macro in older Linux systems.
2542 Sigh. Linux is a fast-moving target. Another generation of Linux uses
2543 glibc 2, which has chosen ip_opts for the structure name. This is now
2544 really a glibc thing rather than a Linux thing, so the condition name
2545 has been changed to reflect this. It is relevant also to GNU/Hurd.
2547 Mac OS 10.x (Darwin) is like the later glibc versions, but without the
2548 setting of the __GLIBC__ macro, so we can't detect it automatically. There's
2549 a special macro defined in the os.h file.
2551 Some DGUX versions on older hardware appear not to support IP options at
2552 all, so there is now a general macro which can be set to cut out this
2555 How to do this properly in IPv6 is not yet known. */
2557 #if !HAVE_IPV6 && !defined(NO_IP_OPTIONS)
2559 #ifdef GLIBC_IP_OPTIONS
2560 #if (!defined __GLIBC__) || (__GLIBC__ < 2)
2565 #elif defined DARWIN_IP_OPTIONS
2571 if (!host_checking && !sender_host_notsocket)
2574 EXIM_SOCKLEN_T optlen = sizeof(struct ip_options) + MAX_IPOPTLEN;
2575 struct ip_options *ipopt = store_get(optlen);
2577 struct ip_opts ipoptblock;
2578 struct ip_opts *ipopt = &ipoptblock;
2579 EXIM_SOCKLEN_T optlen = sizeof(ipoptblock);
2581 struct ipoption ipoptblock;
2582 struct ipoption *ipopt = &ipoptblock;
2583 EXIM_SOCKLEN_T optlen = sizeof(ipoptblock);
2586 /* Occasional genuine failures of getsockopt() have been seen - for
2587 example, "reset by peer". Therefore, just log and give up on this
2588 call, unless the error is ENOPROTOOPT. This error is given by systems
2589 that have the interfaces but not the mechanism - e.g. GNU/Hurd at the time
2590 of writing. So for that error, carry on - we just can't do an IP options
2593 DEBUG(D_receive) debug_printf("checking for IP options\n");
2595 if (getsockopt(fileno(smtp_out), IPPROTO_IP, IP_OPTIONS, US (ipopt),
2598 if (errno != ENOPROTOOPT)
2600 log_write(0, LOG_MAIN, "getsockopt() failed from %s: %s",
2601 host_and_ident(FALSE), strerror(errno));
2602 smtp_printf("451 SMTP service not available\r\n", FALSE);
2607 /* Deal with any IP options that are set. On the systems I have looked at,
2608 the value of MAX_IPOPTLEN has been 40, meaning that there should never be
2609 more logging data than will fit in big_buffer. Nevertheless, after somebody
2610 questioned this code, I've added in some paranoid checking. */
2612 else if (optlen > 0)
2614 uschar *p = big_buffer;
2615 uschar *pend = big_buffer + big_buffer_size;
2616 uschar *opt, *adptr;
2618 struct in_addr addr;
2621 uschar *optstart = US (ipopt->__data);
2623 uschar *optstart = US (ipopt->ip_opts);
2625 uschar *optstart = US (ipopt->ipopt_list);
2628 DEBUG(D_receive) debug_printf("IP options exist\n");
2630 Ustrcpy(p, "IP options on incoming call:");
2633 for (opt = optstart; opt != NULL &&
2634 opt < US (ipopt) + optlen;)
2648 if (!string_format(p, pend-p, " %s [@%s",
2649 (*opt == IPOPT_SSRR)? "SSRR" : "LSRR",
2651 inet_ntoa(*((struct in_addr *)(&(ipopt->faddr))))))
2653 inet_ntoa(ipopt->ip_dst)))
2655 inet_ntoa(ipopt->ipopt_dst)))
2663 optcount = (opt[1] - 3) / sizeof(struct in_addr);
2665 while (optcount-- > 0)
2667 memcpy(&addr, adptr, sizeof(addr));
2668 if (!string_format(p, pend - p - 1, "%s%s",
2669 (optcount == 0)? ":" : "@", inet_ntoa(addr)))
2675 adptr += sizeof(struct in_addr);
2684 if (pend - p < 4 + 3*opt[1]) { opt = NULL; break; }
2687 for (i = 0; i < opt[1]; i++)
2688 p += sprintf(CS p, "%2.2x ", opt[i]);
2697 log_write(0, LOG_MAIN, "%s", big_buffer);
2699 /* Refuse any call with IP options. This is what tcpwrappers 7.5 does. */
2701 log_write(0, LOG_MAIN|LOG_REJECT,
2702 "connection from %s refused (IP options)", host_and_ident(FALSE));
2704 smtp_printf("554 SMTP service not available\r\n", FALSE);
2708 /* Length of options = 0 => there are no options */
2710 else DEBUG(D_receive) debug_printf("no IP options found\n");
2712 #endif /* HAVE_IPV6 && !defined(NO_IP_OPTIONS) */
2714 /* Set keep-alive in socket options. The option is on by default. This
2715 setting is an attempt to get rid of some hanging connections that stick in
2716 read() when the remote end (usually a dialup) goes away. */
2718 if (smtp_accept_keepalive && !sender_host_notsocket)
2719 ip_keepalive(fileno(smtp_out), sender_host_address, FALSE);
2721 /* If the current host matches host_lookup, set the name by doing a
2722 reverse lookup. On failure, sender_host_name will be NULL and
2723 host_lookup_failed will be TRUE. This may or may not be serious - optional
2726 if (verify_check_host(&host_lookup) == OK)
2728 (void)host_name_lookup();
2729 host_build_sender_fullhost();
2732 /* Delay this until we have the full name, if it is looked up. */
2734 set_process_info("handling incoming connection from %s",
2735 host_and_ident(FALSE));
2737 /* Expand smtp_receive_timeout, if needed */
2739 if (smtp_receive_timeout_s)
2742 if ( !(exp = expand_string(smtp_receive_timeout_s))
2744 || (smtp_receive_timeout = readconf_readtime(exp, 0, FALSE)) < 0
2746 log_write(0, LOG_MAIN|LOG_PANIC,
2747 "bad value for smtp_receive_timeout: '%s'", exp ? exp : US"");
2750 /* Test for explicit connection rejection */
2752 if (verify_check_host(&host_reject_connection) == OK)
2754 log_write(L_connection_reject, LOG_MAIN|LOG_REJECT, "refused connection "
2755 "from %s (host_reject_connection)", host_and_ident(FALSE));
2756 smtp_printf("554 SMTP service not available\r\n", FALSE);
2760 /* Test with TCP Wrappers if so configured. There is a problem in that
2761 hosts_ctl() returns 0 (deny) under a number of system failure circumstances,
2762 such as disks dying. In these cases, it is desirable to reject with a 4xx
2763 error instead of a 5xx error. There isn't a "right" way to detect such
2764 problems. The following kludge is used: errno is zeroed before calling
2765 hosts_ctl(). If the result is "reject", a 5xx error is given only if the
2766 value of errno is 0 or ENOENT (which happens if /etc/hosts.{allow,deny} does
2769 #ifdef USE_TCP_WRAPPERS
2771 if (!(tcp_wrappers_name = expand_string(tcp_wrappers_daemon_name)))
2772 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "Expansion of \"%s\" "
2773 "(tcp_wrappers_name) failed: %s", string_printing(tcp_wrappers_name),
2774 expand_string_message);
2776 if (!hosts_ctl(tcp_wrappers_name,
2777 sender_host_name ? CS sender_host_name : STRING_UNKNOWN,
2778 sender_host_address ? CS sender_host_address : STRING_UNKNOWN,
2779 sender_ident ? CS sender_ident : STRING_UNKNOWN))
2781 if (errno == 0 || errno == ENOENT)
2783 HDEBUG(D_receive) debug_printf("tcp wrappers rejection\n");
2784 log_write(L_connection_reject,
2785 LOG_MAIN|LOG_REJECT, "refused connection from %s "
2786 "(tcp wrappers)", host_and_ident(FALSE));
2787 smtp_printf("554 SMTP service not available\r\n", FALSE);
2791 int save_errno = errno;
2792 HDEBUG(D_receive) debug_printf("tcp wrappers rejected with unexpected "
2793 "errno value %d\n", save_errno);
2794 log_write(L_connection_reject,
2795 LOG_MAIN|LOG_REJECT, "temporarily refused connection from %s "
2796 "(tcp wrappers errno=%d)", host_and_ident(FALSE), save_errno);
2797 smtp_printf("451 Temporary local problem - please try later\r\n", FALSE);
2803 /* Check for reserved slots. The value of smtp_accept_count has already been
2804 incremented to include this process. */
2806 if (smtp_accept_max > 0 &&
2807 smtp_accept_count > smtp_accept_max - smtp_accept_reserve)
2809 if ((rc = verify_check_host(&smtp_reserve_hosts)) != OK)
2811 log_write(L_connection_reject,
2812 LOG_MAIN, "temporarily refused connection from %s: not in "
2813 "reserve list: connected=%d max=%d reserve=%d%s",
2814 host_and_ident(FALSE), smtp_accept_count - 1, smtp_accept_max,
2815 smtp_accept_reserve, (rc == DEFER)? " (lookup deferred)" : "");
2816 smtp_printf("421 %s: Too many concurrent SMTP connections; "
2817 "please try again later\r\n", FALSE, smtp_active_hostname);
2820 reserved_host = TRUE;
2823 /* If a load level above which only messages from reserved hosts are
2824 accepted is set, check the load. For incoming calls via the daemon, the
2825 check is done in the superior process if there are no reserved hosts, to
2826 save a fork. In all cases, the load average will already be available
2827 in a global variable at this point. */
2829 if (smtp_load_reserve >= 0 &&
2830 load_average > smtp_load_reserve &&
2832 verify_check_host(&smtp_reserve_hosts) != OK)
2834 log_write(L_connection_reject,
2835 LOG_MAIN, "temporarily refused connection from %s: not in "
2836 "reserve list and load average = %.2f", host_and_ident(FALSE),
2837 (double)load_average/1000.0);
2838 smtp_printf("421 %s: Too much load; please try again later\r\n", FALSE,
2839 smtp_active_hostname);
2843 /* Determine whether unqualified senders or recipients are permitted
2844 for this host. Unfortunately, we have to do this every time, in order to
2845 set the flags so that they can be inspected when considering qualifying
2846 addresses in the headers. For a site that permits no qualification, this
2847 won't take long, however. */
2849 allow_unqualified_sender =
2850 verify_check_host(&sender_unqualified_hosts) == OK;
2852 allow_unqualified_recipient =
2853 verify_check_host(&recipient_unqualified_hosts) == OK;
2855 /* Determine whether HELO/EHLO is required for this host. The requirement
2856 can be hard or soft. */
2858 helo_required = verify_check_host(&helo_verify_hosts) == OK;
2860 helo_verify = verify_check_host(&helo_try_verify_hosts) == OK;
2862 /* Determine whether this hosts is permitted to send syntactic junk
2863 after a HELO or EHLO command. */
2865 helo_accept_junk = verify_check_host(&helo_accept_junk_hosts) == OK;
2868 /* For batch SMTP input we are now done. */
2870 if (smtp_batched_input) return TRUE;
2872 /* If valid Proxy Protocol source is connecting, set up session.
2873 * Failure will not allow any SMTP function other than QUIT. */
2875 #ifdef SUPPORT_PROXY
2876 proxy_session = FALSE;
2877 proxy_session_failed = FALSE;
2878 if (check_proxy_protocol_host())
2879 setup_proxy_protocol_host();
2882 /* Start up TLS if tls_on_connect is set. This is for supporting the legacy
2883 smtps port for use with older style SSL MTAs. */
2886 if (tls_in.on_connect)
2888 if (tls_server_start(tls_require_ciphers, &user_msg) != OK)
2889 return smtp_log_tls_fail(user_msg);
2890 cmd_list[CMD_LIST_TLS_AUTH].is_mail_cmd = TRUE;
2894 /* Run the connect ACL if it exists */
2897 if (acl_smtp_connect)
2900 if ((rc = acl_check(ACL_WHERE_CONNECT, NULL, acl_smtp_connect, &user_msg,
2903 (void) smtp_handle_acl_fail(ACL_WHERE_CONNECT, rc, user_msg, log_msg);
2908 /* Output the initial message for a two-way SMTP connection. It may contain
2909 newlines, which then cause a multi-line response to be given. */
2911 code = US"220"; /* Default status code */
2912 esc = US""; /* Default extended status code */
2913 esclen = 0; /* Length of esc */
2917 if (!(s = expand_string(smtp_banner)))
2918 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "Expansion of \"%s\" (smtp_banner) "
2919 "failed: %s", smtp_banner, expand_string_message);
2925 smtp_message_code(&code, &codelen, &s, NULL, TRUE);
2929 esclen = codelen - 4;
2933 /* Remove any terminating newlines; might as well remove trailing space too */
2936 while (p > s && isspace(p[-1])) p--;
2939 /* It seems that CC:Mail is braindead, and assumes that the greeting message
2940 is all contained in a single IP packet. The original code wrote out the
2941 greeting using several calls to fprint/fputc, and on busy servers this could
2942 cause it to be split over more than one packet - which caused CC:Mail to fall
2943 over when it got the second part of the greeting after sending its first
2944 command. Sigh. To try to avoid this, build the complete greeting message
2945 first, and output it in one fell swoop. This gives a better chance of it
2946 ending up as a single packet. */
2948 ss = string_get(256);
2951 do /* At least once, in case we have an empty string */
2954 uschar *linebreak = Ustrchr(p, '\n');
2955 ss = string_catn(ss, code, 3);
2959 ss = string_catn(ss, US" ", 1);
2963 len = linebreak - p;
2964 ss = string_catn(ss, US"-", 1);
2966 ss = string_catn(ss, esc, esclen);
2967 ss = string_catn(ss, p, len);
2968 ss = string_catn(ss, US"\r\n", 2);
2974 /* Before we write the banner, check that there is no input pending, unless
2975 this synchronisation check is disabled. */
2979 unsigned n = smtp_inend - smtp_inptr;
2982 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP protocol "
2983 "synchronization error (input sent without waiting for greeting): "
2984 "rejected connection from %s input=\"%s\"", host_and_ident(TRUE),
2985 string_printing(string_copyn(smtp_inptr, n)));
2986 smtp_printf("554 SMTP synchronization error\r\n", FALSE);
2990 /* Now output the banner */
2992 smtp_printf("%s", FALSE, string_from_gstring(ss));
2994 /* Attempt to see if we sent the banner before the last ACK of the 3-way
2995 handshake arrived. If so we must have managed a TFO. */
3008 /*************************************************
3009 * Handle SMTP syntax and protocol errors *
3010 *************************************************/
3012 /* Write to the log for SMTP syntax errors in incoming commands, if configured
3013 to do so. Then transmit the error response. The return value depends on the
3014 number of syntax and protocol errors in this SMTP session.
3017 type error type, given as a log flag bit
3018 code response code; <= 0 means don't send a response
3019 data data to reflect in the response (can be NULL)
3020 errmess the error message
3022 Returns: -1 limit of syntax/protocol errors NOT exceeded
3023 +1 limit of syntax/protocol errors IS exceeded
3025 These values fit in with the values of the "done" variable in the main
3026 processing loop in smtp_setup_msg(). */
3029 synprot_error(int type, int code, uschar *data, uschar *errmess)
3033 log_write(type, LOG_MAIN, "SMTP %s error in \"%s\" %s %s",
3034 (type == L_smtp_syntax_error)? "syntax" : "protocol",
3035 string_printing(smtp_cmd_buffer), host_and_ident(TRUE), errmess);
3037 if (++synprot_error_count > smtp_max_synprot_errors)
3040 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
3041 "syntax or protocol errors (last command was \"%s\")",
3042 host_and_ident(FALSE), string_printing(smtp_cmd_buffer));
3047 smtp_printf("%d%c%s%s%s\r\n", FALSE, code, yield == 1 ? '-' : ' ',
3048 data ? data : US"", data ? US": " : US"", errmess);
3050 smtp_printf("%d Too many syntax or protocol errors\r\n", FALSE, code);
3059 /*************************************************
3060 * Send SMTP response, possibly multiline *
3061 *************************************************/
3063 /* There are, it seems, broken clients out there that cannot handle multiline
3064 responses. If no_multiline_responses is TRUE (it can be set from an ACL), we
3065 output nothing for non-final calls, and only the first line for anything else.
3068 code SMTP code, may involve extended status codes
3069 codelen length of smtp code; if > 4 there's an ESC
3070 final FALSE if the last line isn't the final line
3071 msg message text, possibly containing newlines
3077 smtp_respond(uschar* code, int codelen, BOOL final, uschar *msg)
3082 if (!final && no_multiline_responses) return;
3087 esclen = codelen - 4;
3090 /* If this is the first output for a (non-batch) RCPT command, see if all RCPTs
3091 have had the same. Note: this code is also present in smtp_printf(). It would
3092 be tidier to have it only in one place, but when it was added, it was easier to
3093 do it that way, so as not to have to mess with the code for the RCPT command,
3094 which sometimes uses smtp_printf() and sometimes smtp_respond(). */
3096 if (rcpt_in_progress)
3098 if (rcpt_smtp_response == NULL)
3099 rcpt_smtp_response = string_copy(msg);
3100 else if (rcpt_smtp_response_same &&
3101 Ustrcmp(rcpt_smtp_response, msg) != 0)
3102 rcpt_smtp_response_same = FALSE;
3103 rcpt_in_progress = FALSE;
3106 /* Now output the message, splitting it up into multiple lines if necessary.
3107 We only handle pipelining these responses as far as nonfinal/final groups,
3108 not the whole MAIL/RCPT/DATA response set. */
3112 uschar *nl = Ustrchr(msg, '\n');
3115 smtp_printf("%.3s%c%.*s%s\r\n", !final, code, final ? ' ':'-', esclen, esc, msg);
3118 else if (nl[1] == 0 || no_multiline_responses)
3120 smtp_printf("%.3s%c%.*s%.*s\r\n", !final, code, final ? ' ':'-', esclen, esc,
3121 (int)(nl - msg), msg);
3126 smtp_printf("%.3s-%.*s%.*s\r\n", TRUE, code, esclen, esc, (int)(nl - msg), msg);
3128 while (isspace(*msg)) msg++;
3136 /*************************************************
3137 * Parse user SMTP message *
3138 *************************************************/
3140 /* This function allows for user messages overriding the response code details
3141 by providing a suitable response code string at the start of the message
3142 user_msg. Check the message for starting with a response code and optionally an
3143 extended status code. If found, check that the first digit is valid, and if so,
3144 change the code pointer and length to use the replacement. An invalid code
3145 causes a panic log; in this case, if the log messages is the same as the user
3146 message, we must also adjust the value of the log message to show the code that
3147 is actually going to be used (the original one).
3149 This function is global because it is called from receive.c as well as within
3152 Note that the code length returned includes the terminating whitespace
3153 character, which is always included in the regex match.
3156 code SMTP code, may involve extended status codes
3157 codelen length of smtp code; if > 4 there's an ESC
3159 log_msg optional log message, to be adjusted with the new SMTP code
3160 check_valid if true, verify the response code
3166 smtp_message_code(uschar **code, int *codelen, uschar **msg, uschar **log_msg,
3172 if (!msg || !*msg) return;
3174 if ((n = pcre_exec(regex_smtp_code, NULL, CS *msg, Ustrlen(*msg), 0,
3175 PCRE_EOPT, ovector, sizeof(ovector)/sizeof(int))) < 0) return;
3177 if (check_valid && (*msg)[0] != (*code)[0])
3179 log_write(0, LOG_MAIN|LOG_PANIC, "configured error code starts with "
3180 "incorrect digit (expected %c) in \"%s\"", (*code)[0], *msg);
3181 if (log_msg != NULL && *log_msg == *msg)
3182 *log_msg = string_sprintf("%s %s", *code, *log_msg + ovector[1]);
3187 *codelen = ovector[1]; /* Includes final space */
3189 *msg += ovector[1]; /* Chop the code off the message */
3196 /*************************************************
3197 * Handle an ACL failure *
3198 *************************************************/
3200 /* This function is called when acl_check() fails. As well as calls from within
3201 this module, it is called from receive.c for an ACL after DATA. It sorts out
3202 logging the incident, and sends the error response. A message containing
3203 newlines is turned into a multiline SMTP response, but for logging, only the
3206 There's a table of default permanent failure response codes to use in
3207 globals.c, along with the table of names. VFRY is special. Despite RFC1123 it
3208 defaults disabled in Exim. However, discussion in connection with RFC 821bis
3209 (aka RFC 2821) has concluded that the response should be 252 in the disabled
3210 state, because there are broken clients that try VRFY before RCPT. A 5xx
3211 response should be given only when the address is positively known to be
3212 undeliverable. Sigh. We return 252 if there is no VRFY ACL or it provides
3213 no explicit code, but if there is one we let it know best.
3214 Also, for ETRN, 458 is given on refusal, and for AUTH, 503.
3216 From Exim 4.63, it is possible to override the response code details by
3217 providing a suitable response code string at the start of the message provided
3218 in user_msg. The code's first digit is checked for validity.
3221 where where the ACL was called from
3223 user_msg a message that can be included in an SMTP response
3224 log_msg a message for logging
3226 Returns: 0 in most cases
3227 2 if the failure code was FAIL_DROP, in which case the
3228 SMTP connection should be dropped (this value fits with the
3229 "done" variable in smtp_setup_msg() below)
3233 smtp_handle_acl_fail(int where, int rc, uschar *user_msg, uschar *log_msg)
3235 BOOL drop = rc == FAIL_DROP;
3239 uschar *sender_info = US"";
3241 #ifdef WITH_CONTENT_SCAN
3242 where == ACL_WHERE_MIME ? US"during MIME ACL checks" :
3244 where == ACL_WHERE_PREDATA ? US"DATA" :
3245 where == ACL_WHERE_DATA ? US"after DATA" :
3246 #ifndef DISABLE_PRDR
3247 where == ACL_WHERE_PRDR ? US"after DATA PRDR" :
3250 string_sprintf("%s %s", acl_wherenames[where], smtp_cmd_data) :
3251 string_sprintf("%s in \"connect\" ACL", acl_wherenames[where]);
3253 if (drop) rc = FAIL;
3255 /* Set the default SMTP code, and allow a user message to change it. */
3257 smtp_code = rc == FAIL ? acl_wherecodes[where] : US"451";
3258 smtp_message_code(&smtp_code, &codelen, &user_msg, &log_msg,
3259 where != ACL_WHERE_VRFY);
3261 /* We used to have sender_address here; however, there was a bug that was not
3262 updating sender_address after a rewrite during a verify. When this bug was
3263 fixed, sender_address at this point became the rewritten address. I'm not sure
3264 this is what should be logged, so I've changed to logging the unrewritten
3265 address to retain backward compatibility. */
3267 #ifndef WITH_CONTENT_SCAN
3268 if (where == ACL_WHERE_RCPT || where == ACL_WHERE_DATA)
3270 if (where == ACL_WHERE_RCPT || where == ACL_WHERE_DATA || where == ACL_WHERE_MIME)
3273 sender_info = string_sprintf("F=<%s>%s%s%s%s ",
3274 sender_address_unrewritten ? sender_address_unrewritten : sender_address,
3275 sender_host_authenticated ? US" A=" : US"",
3276 sender_host_authenticated ? sender_host_authenticated : US"",
3277 sender_host_authenticated && authenticated_id ? US":" : US"",
3278 sender_host_authenticated && authenticated_id ? authenticated_id : US""
3282 /* If there's been a sender verification failure with a specific message, and
3283 we have not sent a response about it yet, do so now, as a preliminary line for
3284 failures, but not defers. However, always log it for defer, and log it for fail
3285 unless the sender_verify_fail log selector has been turned off. */
3287 if (sender_verified_failed &&
3288 !testflag(sender_verified_failed, af_sverify_told))
3290 BOOL save_rcpt_in_progress = rcpt_in_progress;
3291 rcpt_in_progress = FALSE; /* So as not to treat these as the error */
3293 setflag(sender_verified_failed, af_sverify_told);
3295 if (rc != FAIL || LOGGING(sender_verify_fail))
3296 log_write(0, LOG_MAIN|LOG_REJECT, "%s sender verify %s for <%s>%s",
3297 host_and_ident(TRUE),
3298 ((sender_verified_failed->special_action & 255) == DEFER)? "defer":"fail",
3299 sender_verified_failed->address,
3300 (sender_verified_failed->message == NULL)? US"" :
3301 string_sprintf(": %s", sender_verified_failed->message));
3303 if (rc == FAIL && sender_verified_failed->user_message)
3304 smtp_respond(smtp_code, codelen, FALSE, string_sprintf(
3305 testflag(sender_verified_failed, af_verify_pmfail)?
3306 "Postmaster verification failed while checking <%s>\n%s\n"
3307 "Several RFCs state that you are required to have a postmaster\n"
3308 "mailbox for each mail domain. This host does not accept mail\n"
3309 "from domains whose servers reject the postmaster address."
3311 testflag(sender_verified_failed, af_verify_nsfail)?
3312 "Callback setup failed while verifying <%s>\n%s\n"
3313 "The initial connection, or a HELO or MAIL FROM:<> command was\n"
3314 "rejected. Refusing MAIL FROM:<> does not help fight spam, disregards\n"
3315 "RFC requirements, and stops you from receiving standard bounce\n"
3316 "messages. This host does not accept mail from domains whose servers\n"
3319 "Verification failed for <%s>\n%s",
3320 sender_verified_failed->address,
3321 sender_verified_failed->user_message));
3323 rcpt_in_progress = save_rcpt_in_progress;
3326 /* Sort out text for logging */
3328 log_msg = log_msg ? string_sprintf(": %s", log_msg) : US"";
3329 if ((lognl = Ustrchr(log_msg, '\n'))) *lognl = 0;
3331 /* Send permanent failure response to the command, but the code used isn't
3332 always a 5xx one - see comments at the start of this function. If the original
3333 rc was FAIL_DROP we drop the connection and yield 2. */
3336 smtp_respond(smtp_code, codelen, TRUE,
3337 user_msg ? user_msg : US"Administrative prohibition");
3339 /* Send temporary failure response to the command. Don't give any details,
3340 unless acl_temp_details is set. This is TRUE for a callout defer, a "defer"
3341 verb, and for a header verify when smtp_return_error_details is set.
3343 This conditional logic is all somewhat of a mess because of the odd
3344 interactions between temp_details and return_error_details. One day it should
3345 be re-implemented in a tidier fashion. */
3348 if (acl_temp_details && user_msg)
3350 if ( smtp_return_error_details
3351 && sender_verified_failed
3352 && sender_verified_failed->message
3354 smtp_respond(smtp_code, codelen, FALSE, sender_verified_failed->message);
3356 smtp_respond(smtp_code, codelen, TRUE, user_msg);
3359 smtp_respond(smtp_code, codelen, TRUE,
3360 US"Temporary local problem - please try later");
3362 /* Log the incident to the logs that are specified by log_reject_target
3363 (default main, reject). This can be empty to suppress logging of rejections. If
3364 the connection is not forcibly to be dropped, return 0. Otherwise, log why it
3365 is closing if required and return 2. */
3367 if (log_reject_target != 0)
3370 gstring * g = s_tlslog(NULL);
3371 uschar * tls = string_from_gstring(g);
3372 if (!tls) tls = US"";
3374 uschar * tls = US"";
3376 log_write(where == ACL_WHERE_CONNECT ? L_connection_reject : 0,
3377 log_reject_target, "%s%s%s %s%srejected %s%s",
3378 LOGGING(dnssec) && sender_host_dnssec ? US" DS" : US"",
3379 host_and_ident(TRUE),
3382 rc == FAIL ? US"" : US"temporarily ",
3386 if (!drop) return 0;
3388 log_write(L_smtp_connection, LOG_MAIN, "%s closed by DROP in ACL",
3389 smtp_get_connection_info());
3391 /* Run the not-quit ACL, but without any custom messages. This should not be a
3392 problem, because we get here only if some other ACL has issued "drop", and
3393 in that case, *its* custom messages will have been used above. */
3395 smtp_notquit_exit(US"acl-drop", NULL, NULL);
3402 /*************************************************
3403 * Handle SMTP exit when QUIT is not given *
3404 *************************************************/
3406 /* This function provides a logging/statistics hook for when an SMTP connection
3407 is dropped on the floor or the other end goes away. It's a global function
3408 because it's called from receive.c as well as this module. As well as running
3409 the NOTQUIT ACL, if there is one, this function also outputs a final SMTP
3410 response, either with a custom message from the ACL, or using a default. There
3411 is one case, however, when no message is output - after "drop". In that case,
3412 the ACL that obeyed "drop" has already supplied the custom message, and NULL is
3413 passed to this function.
3415 In case things go wrong while processing this function, causing an error that
3416 may re-enter this function, there is a recursion check.
3419 reason What $smtp_notquit_reason will be set to in the ACL;
3420 if NULL, the ACL is not run
3421 code The error code to return as part of the response
3422 defaultrespond The default message if there's no user_msg
3428 smtp_notquit_exit(uschar *reason, uschar *code, uschar *defaultrespond, ...)
3431 uschar *user_msg = NULL;
3432 uschar *log_msg = NULL;
3434 /* Check for recursive acll */
3436 if (smtp_exit_function_called)
3438 log_write(0, LOG_PANIC, "smtp_notquit_exit() called more than once (%s)",
3442 smtp_exit_function_called = TRUE;
3444 /* Call the not-QUIT ACL, if there is one, unless no reason is given. */
3446 if (acl_smtp_notquit && reason)
3448 smtp_notquit_reason = reason;
3449 if ((rc = acl_check(ACL_WHERE_NOTQUIT, NULL, acl_smtp_notquit, &user_msg,
3450 &log_msg)) == ERROR)
3451 log_write(0, LOG_MAIN|LOG_PANIC, "ACL for not-QUIT returned ERROR: %s",
3455 /* Write an SMTP response if we are expected to give one. As the default
3456 responses are all internal, they should always fit in the buffer, but code a
3457 warning, just in case. Note that string_vformat() still leaves a complete
3458 string, even if it is incomplete. */
3460 if (code && defaultrespond)
3463 smtp_respond(code, 3, TRUE, user_msg);
3468 va_start(ap, defaultrespond);
3469 if (!string_vformat(buffer, sizeof(buffer), CS defaultrespond, ap))
3470 log_write(0, LOG_MAIN|LOG_PANIC, "string too large in smtp_notquit_exit()");
3471 smtp_printf("%s %s\r\n", FALSE, code, buffer);
3481 /*************************************************
3482 * Verify HELO argument *
3483 *************************************************/
3485 /* This function is called if helo_verify_hosts or helo_try_verify_hosts is
3486 matched. It is also called from ACL processing if verify = helo is used and
3487 verification was not previously tried (i.e. helo_try_verify_hosts was not
3488 matched). The result of its processing is to set helo_verified and
3489 helo_verify_failed. These variables should both be FALSE for this function to
3492 Note that EHLO/HELO is legitimately allowed to quote an address literal. Allow
3493 for IPv6 ::ffff: literals.
3496 Returns: TRUE if testing was completed;
3497 FALSE on a temporary failure
3501 smtp_verify_helo(void)
3505 HDEBUG(D_receive) debug_printf("verifying EHLO/HELO argument \"%s\"\n",
3508 if (sender_helo_name == NULL)
3510 HDEBUG(D_receive) debug_printf("no EHLO/HELO command was issued\n");
3513 /* Deal with the case of -bs without an IP address */
3515 else if (sender_host_address == NULL)
3517 HDEBUG(D_receive) debug_printf("no client IP address: assume success\n");
3518 helo_verified = TRUE;
3521 /* Deal with the more common case when there is a sending IP address */
3523 else if (sender_helo_name[0] == '[')
3525 helo_verified = Ustrncmp(sender_helo_name+1, sender_host_address,
3526 Ustrlen(sender_host_address)) == 0;
3531 if (strncmpic(sender_host_address, US"::ffff:", 7) == 0)
3532 helo_verified = Ustrncmp(sender_helo_name + 1,
3533 sender_host_address + 7, Ustrlen(sender_host_address) - 7) == 0;
3538 { if (helo_verified) debug_printf("matched host address\n"); }
3541 /* Do a reverse lookup if one hasn't already given a positive or negative
3542 response. If that fails, or the name doesn't match, try checking with a forward
3547 if (sender_host_name == NULL && !host_lookup_failed)
3548 yield = host_name_lookup() != DEFER;
3550 /* If a host name is known, check it and all its aliases. */
3552 if (sender_host_name)
3553 if ((helo_verified = strcmpic(sender_host_name, sender_helo_name) == 0))
3555 sender_helo_dnssec = sender_host_dnssec;
3556 HDEBUG(D_receive) debug_printf("matched host name\n");
3560 uschar **aliases = sender_host_aliases;
3562 if ((helo_verified = strcmpic(*aliases++, sender_helo_name) == 0))
3564 sender_helo_dnssec = sender_host_dnssec;
3568 HDEBUG(D_receive) if (helo_verified)
3569 debug_printf("matched alias %s\n", *(--aliases));
3572 /* Final attempt: try a forward lookup of the helo name */
3581 h.name = sender_helo_name;
3588 HDEBUG(D_receive) debug_printf("getting IP address for %s\n",
3590 rc = host_find_bydns(&h, NULL, HOST_FIND_BY_A | HOST_FIND_BY_AAAA,
3591 NULL, NULL, NULL, &d, NULL, NULL);
3592 if (rc == HOST_FOUND || rc == HOST_FOUND_LOCAL)
3593 for (hh = &h; hh; hh = hh->next)
3594 if (Ustrcmp(hh->address, sender_host_address) == 0)
3596 helo_verified = TRUE;
3597 if (h.dnssec == DS_YES) sender_helo_dnssec = TRUE;
3600 debug_printf("IP address for %s matches calling address\n"
3601 "Forward DNS security status: %sverified\n",
3602 sender_helo_name, sender_helo_dnssec ? "" : "un");
3609 if (!helo_verified) helo_verify_failed = TRUE; /* We've tried ... */
3616 /*************************************************
3617 * Send user response message *
3618 *************************************************/
3620 /* This function is passed a default response code and a user message. It calls
3621 smtp_message_code() to check and possibly modify the response code, and then
3622 calls smtp_respond() to transmit the response. I put this into a function
3623 just to avoid a lot of repetition.
3626 code the response code
3627 user_msg the user message
3633 smtp_user_msg(uschar *code, uschar *user_msg)
3636 smtp_message_code(&code, &len, &user_msg, NULL, TRUE);
3637 smtp_respond(code, len, TRUE, user_msg);
3643 smtp_in_auth(auth_instance *au, uschar ** s, uschar ** ss)
3645 const uschar *set_id = NULL;
3648 /* Run the checking code, passing the remainder of the command line as
3649 data. Initials the $auth<n> variables as empty. Initialize $0 empty and set
3650 it as the only set numerical variable. The authenticator may set $auth<n>
3651 and also set other numeric variables. The $auth<n> variables are preferred
3652 nowadays; the numerical variables remain for backwards compatibility.
3654 Afterwards, have a go at expanding the set_id string, even if
3655 authentication failed - for bad passwords it can be useful to log the
3656 userid. On success, require set_id to expand and exist, and put it in
3657 authenticated_id. Save this in permanent store, as the working store gets
3658 reset at HELO, RSET, etc. */
3660 for (i = 0; i < AUTH_VARS; i++) auth_vars[i] = NULL;
3662 expand_nlength[0] = 0; /* $0 contains nothing */
3664 rc = (au->info->servercode)(au, smtp_cmd_data);
3665 if (au->set_id) set_id = expand_string(au->set_id);
3666 expand_nmax = -1; /* Reset numeric variables */
3667 for (i = 0; i < AUTH_VARS; i++) auth_vars[i] = NULL; /* Reset $auth<n> */
3669 /* The value of authenticated_id is stored in the spool file and printed in
3670 log lines. It must not contain binary zeros or newline characters. In
3671 normal use, it never will, but when playing around or testing, this error
3672 can (did) happen. To guard against this, ensure that the id contains only
3673 printing characters. */
3675 if (set_id) set_id = string_printing(set_id);
3677 /* For the non-OK cases, set up additional logging data if set_id
3681 set_id = set_id && *set_id
3682 ? string_sprintf(" (set_id=%s)", set_id) : US"";
3684 /* Switch on the result */
3689 if (!au->set_id || set_id) /* Complete success */
3691 if (set_id) authenticated_id = string_copy_malloc(set_id);
3692 sender_host_authenticated = au->name;
3693 sender_host_auth_pubname = au->public_name;
3694 authentication_failed = FALSE;
3695 authenticated_fail_id = NULL; /* Impossible to already be set? */
3698 (sender_host_address ? protocols : protocols_local)
3699 [pextend + pauthed + (tls_in.active >= 0 ? pcrpted:0)];
3700 *s = *ss = US"235 Authentication succeeded";
3701 authenticated_by = au;
3705 /* Authentication succeeded, but we failed to expand the set_id string.
3706 Treat this as a temporary error. */
3708 auth_defer_msg = expand_string_message;
3712 if (set_id) authenticated_fail_id = string_copy_malloc(set_id);
3713 *s = string_sprintf("435 Unable to authenticate at present%s",
3714 auth_defer_user_msg);
3715 *ss = string_sprintf("435 Unable to authenticate at present%s: %s",
3716 set_id, auth_defer_msg);
3720 *s = *ss = US"501 Invalid base64 data";
3724 *s = *ss = US"501 Authentication cancelled";
3728 *s = *ss = US"553 Initial data not expected";
3732 if (set_id) authenticated_fail_id = string_copy_malloc(set_id);
3733 *s = US"535 Incorrect authentication data";
3734 *ss = string_sprintf("535 Incorrect authentication data%s", set_id);
3738 if (set_id) authenticated_fail_id = string_copy_malloc(set_id);
3739 *s = US"435 Internal error";
3740 *ss = string_sprintf("435 Internal error%s: return %d from authentication "
3741 "check", set_id, rc);
3753 qualify_recipient(uschar ** recipient, uschar * smtp_cmd_data, uschar * tag)
3756 if (allow_unqualified_recipient || strcmpic(*recipient, US"postmaster") == 0)
3758 DEBUG(D_receive) debug_printf("unqualified address %s accepted\n",
3760 rd = Ustrlen(recipient) + 1;
3761 *recipient = rewrite_address_qualify(*recipient, TRUE);
3764 smtp_printf("501 %s: recipient address must contain a domain\r\n", FALSE,
3766 log_write(L_smtp_syntax_error,
3767 LOG_MAIN|LOG_REJECT, "unqualified %s rejected: <%s> %s%s",
3768 tag, *recipient, host_and_ident(TRUE), host_lookup_msg);
3776 smtp_quit_handler(uschar ** user_msgp, uschar ** log_msgp)
3779 incomplete_transaction_log(US"QUIT");
3782 int rc = acl_check(ACL_WHERE_QUIT, NULL, acl_smtp_quit, user_msgp, log_msgp);
3784 log_write(0, LOG_MAIN|LOG_PANIC, "ACL for QUIT returned ERROR: %s",
3788 smtp_respond(US"221", 3, TRUE, *user_msgp);
3790 smtp_printf("221 %s closing connection\r\n", FALSE, smtp_active_hostname);
3793 tls_close(TRUE, TLS_SHUTDOWN_NOWAIT);
3796 log_write(L_smtp_connection, LOG_MAIN, "%s closed by QUIT",
3797 smtp_get_connection_info());
3802 smtp_rset_handler(void)
3805 incomplete_transaction_log(US"RSET");
3806 smtp_printf("250 Reset OK\r\n", FALSE);
3807 cmd_list[CMD_LIST_RSET].is_mail_cmd = FALSE;
3812 /*************************************************
3813 * Initialize for SMTP incoming message *
3814 *************************************************/
3816 /* This function conducts the initial dialogue at the start of an incoming SMTP
3817 message, and builds a list of recipients. However, if the incoming message
3818 is part of a batch (-bS option) a separate function is called since it would
3819 be messy having tests splattered about all over this function. This function
3820 therefore handles the case where interaction is occurring. The input and output
3821 files are set up in smtp_in and smtp_out.
3823 The global recipients_list is set to point to a vector of recipient_item
3824 blocks, whose number is given by recipients_count. This is extended by the
3825 receive_add_recipient() function. The global variable sender_address is set to
3826 the sender's address. The yield is +1 if a message has been successfully
3827 started, 0 if a QUIT command was encountered or the connection was refused from
3828 the particular host, or -1 if the connection was lost.
3832 Returns: > 0 message successfully started (reached DATA)
3833 = 0 QUIT read or end of file reached or call refused
3838 smtp_setup_msg(void)
3841 BOOL toomany = FALSE;
3842 BOOL discarded = FALSE;
3843 BOOL last_was_rej_mail = FALSE;
3844 BOOL last_was_rcpt = FALSE;
3845 void *reset_point = store_get(0);
3847 DEBUG(D_receive) debug_printf("smtp_setup_msg entered\n");
3849 /* Reset for start of new message. We allow one RSET not to be counted as a
3850 nonmail command, for those MTAs that insist on sending it between every
3851 message. Ditto for EHLO/HELO and for STARTTLS, to allow for going in and out of
3852 TLS between messages (an Exim client may do this if it has messages queued up
3853 for the host). Note: we do NOT reset AUTH at this point. */
3855 smtp_reset(reset_point);
3856 message_ended = END_NOTSTARTED;
3858 chunking_state = chunking_offered ? CHUNKING_OFFERED : CHUNKING_NOT_OFFERED;
3860 cmd_list[CMD_LIST_RSET].is_mail_cmd = TRUE;
3861 cmd_list[CMD_LIST_HELO].is_mail_cmd = TRUE;
3862 cmd_list[CMD_LIST_EHLO].is_mail_cmd = TRUE;
3864 cmd_list[CMD_LIST_STARTTLS].is_mail_cmd = TRUE;
3867 /* Set the local signal handler for SIGTERM - it tries to end off tidily */
3869 had_command_sigterm = 0;
3870 os_non_restarting_signal(SIGTERM, command_sigterm_handler);
3872 /* Batched SMTP is handled in a different function. */
3874 if (smtp_batched_input) return smtp_setup_batch_msg();
3876 /* Deal with SMTP commands. This loop is exited by setting done to a POSITIVE
3877 value. The values are 2 larger than the required yield of the function. */
3881 const uschar **argv;
3882 uschar *etrn_command;
3883 uschar *etrn_serialize_key;
3885 uschar *log_msg, *smtp_code;
3886 uschar *user_msg = NULL;
3887 uschar *recipient = NULL;
3888 uschar *hello = NULL;
3890 BOOL was_rej_mail = FALSE;
3891 BOOL was_rcpt = FALSE;
3892 void (*oldsignal)(int);
3894 int start, end, sender_domain, recipient_domain;
3898 uschar *orcpt = NULL;
3903 /* Check once per STARTTLS or SSL-on-connect for a TLS AUTH */
3904 if ( tls_in.active >= 0
3906 && tls_in.certificate_verified
3907 && cmd_list[CMD_LIST_TLS_AUTH].is_mail_cmd
3910 cmd_list[CMD_LIST_TLS_AUTH].is_mail_cmd = FALSE;
3912 for (au = auths; au; au = au->next)
3913 if (strcmpic(US"tls", au->driver_name) == 0)
3916 && (rc = acl_check(ACL_WHERE_AUTH, NULL, acl_smtp_auth,
3917 &user_msg, &log_msg)) != OK
3919 done = smtp_handle_acl_fail(ACL_WHERE_AUTH, rc, user_msg, log_msg);
3922 smtp_cmd_data = NULL;
3924 if (smtp_in_auth(au, &s, &ss) == OK)
3925 { DEBUG(D_auth) debug_printf("tls auth succeeded\n"); }
3927 { DEBUG(D_auth) debug_printf("tls auth not succeeded\n"); }
3935 if (smtp_in) /* Avoid pure-ACKs while in cmd pingpong phase */
3936 (void) setsockopt(fileno(smtp_in), IPPROTO_TCP, TCP_QUICKACK,
3937 US &off, sizeof(off));
3940 switch(smtp_read_command(TRUE, GETC_BUFFER_UNLIMITED))
3942 /* The AUTH command is not permitted to occur inside a transaction, and may
3943 occur successfully only once per connection. Actually, that isn't quite
3944 true. When TLS is started, all previous information about a connection must
3945 be discarded, so a new AUTH is permitted at that time.
3947 AUTH may only be used when it has been advertised. However, it seems that
3948 there are clients that send AUTH when it hasn't been advertised, some of
3949 them even doing this after HELO. And there are MTAs that accept this. Sigh.
3950 So there's a get-out that allows this to happen.
3952 AUTH is initially labelled as a "nonmail command" so that one occurrence
3953 doesn't get counted. We change the label here so that multiple failing
3954 AUTHS will eventually hit the nonmail threshold. */
3958 authentication_failed = TRUE;
3959 cmd_list[CMD_LIST_AUTH].is_mail_cmd = FALSE;
3961 if (!auth_advertised && !allow_auth_unadvertised)
3963 done = synprot_error(L_smtp_protocol_error, 503, NULL,
3964 US"AUTH command used when not advertised");
3967 if (sender_host_authenticated)
3969 done = synprot_error(L_smtp_protocol_error, 503, NULL,
3970 US"already authenticated");
3975 done = synprot_error(L_smtp_protocol_error, 503, NULL,
3976 US"not permitted in mail transaction");
3983 && (rc = acl_check(ACL_WHERE_AUTH, NULL, acl_smtp_auth,
3984 &user_msg, &log_msg)) != OK
3987 done = smtp_handle_acl_fail(ACL_WHERE_AUTH, rc, user_msg, log_msg);
3991 /* Find the name of the requested authentication mechanism. */
3994 while ((c = *smtp_cmd_data) != 0 && !isspace(c))
3996 if (!isalnum(c) && c != '-' && c != '_')
3998 done = synprot_error(L_smtp_syntax_error, 501, NULL,
3999 US"invalid character in authentication mechanism name");
4005 /* If not at the end of the line, we must be at white space. Terminate the
4006 name and move the pointer on to any data that may be present. */
4008 if (*smtp_cmd_data != 0)
4010 *smtp_cmd_data++ = 0;
4011 while (isspace(*smtp_cmd_data)) smtp_cmd_data++;
4014 /* Search for an authentication mechanism which is configured for use
4015 as a server and which has been advertised (unless, sigh, allow_auth_
4016 unadvertised is set). */
4018 for (au = auths; au; au = au->next)
4019 if (strcmpic(s, au->public_name) == 0 && au->server &&
4020 (au->advertised || allow_auth_unadvertised))
4025 c = smtp_in_auth(au, &s, &ss);
4027 smtp_printf("%s\r\n", FALSE, s);
4029 log_write(0, LOG_MAIN|LOG_REJECT, "%s authenticator failed for %s: %s",
4030 au->name, host_and_ident(FALSE), ss);
4033 done = synprot_error(L_smtp_protocol_error, 504, NULL,
4034 string_sprintf("%s authentication mechanism not supported", s));
4036 break; /* AUTH_CMD */
4038 /* The HELO/EHLO commands are permitted to appear in the middle of a
4039 session as well as at the beginning. They have the effect of a reset in
4040 addition to their other functions. Their absence at the start cannot be
4041 taken to be an error.
4045 If the EHLO command is not acceptable to the SMTP server, 501, 500,
4046 or 502 failure replies MUST be returned as appropriate. The SMTP
4047 server MUST stay in the same state after transmitting these replies
4048 that it was in before the EHLO was received.
4050 Therefore, we do not do the reset until after checking the command for
4051 acceptability. This change was made for Exim release 4.11. Previously
4052 it did the reset first. */
4065 HELO_EHLO: /* Common code for HELO and EHLO */
4066 cmd_list[CMD_LIST_HELO].is_mail_cmd = FALSE;
4067 cmd_list[CMD_LIST_EHLO].is_mail_cmd = FALSE;
4069 /* Reject the HELO if its argument was invalid or non-existent. A
4070 successful check causes the argument to be saved in malloc store. */
4072 if (!check_helo(smtp_cmd_data))
4074 smtp_printf("501 Syntactically invalid %s argument(s)\r\n", FALSE, hello);
4076 log_write(0, LOG_MAIN|LOG_REJECT, "rejected %s from %s: syntactically "
4077 "invalid argument(s): %s", hello, host_and_ident(FALSE),
4078 (*smtp_cmd_argument == 0)? US"(no argument given)" :
4079 string_printing(smtp_cmd_argument));
4081 if (++synprot_error_count > smtp_max_synprot_errors)
4083 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
4084 "syntax or protocol errors (last command was \"%s\")",
4085 host_and_ident(FALSE), string_printing(smtp_cmd_buffer));
4092 /* If sender_host_unknown is true, we have got here via the -bs interface,
4093 not called from inetd. Otherwise, we are running an IP connection and the
4094 host address will be set. If the helo name is the primary name of this
4095 host and we haven't done a reverse lookup, force one now. If helo_required
4096 is set, ensure that the HELO name matches the actual host. If helo_verify
4097 is set, do the same check, but softly. */
4099 if (!sender_host_unknown)
4101 BOOL old_helo_verified = helo_verified;
4102 uschar *p = smtp_cmd_data;
4104 while (*p != 0 && !isspace(*p)) { *p = tolower(*p); p++; }
4107 /* Force a reverse lookup if HELO quoted something in helo_lookup_domains
4108 because otherwise the log can be confusing. */
4110 if ( !sender_host_name
4111 && (deliver_domain = sender_helo_name, /* set $domain */
4112 match_isinlist(sender_helo_name, CUSS &helo_lookup_domains, 0,
4113 &domainlist_anchor, NULL, MCL_DOMAIN, TRUE, NULL)) == OK)
4114 (void)host_name_lookup();
4116 /* Rebuild the fullhost info to include the HELO name (and the real name
4117 if it was looked up.) */
4119 host_build_sender_fullhost(); /* Rebuild */
4120 set_process_info("handling%s incoming connection from %s",
4121 (tls_in.active >= 0)? " TLS" : "", host_and_ident(FALSE));
4123 /* Verify if configured. This doesn't give much security, but it does
4124 make some people happy to be able to do it. If helo_required is set,
4125 (host matches helo_verify_hosts) failure forces rejection. If helo_verify
4126 is set (host matches helo_try_verify_hosts), it does not. This is perhaps
4127 now obsolescent, since the verification can now be requested selectively
4130 helo_verified = helo_verify_failed = sender_helo_dnssec = FALSE;
4131 if (helo_required || helo_verify)
4133 BOOL tempfail = !smtp_verify_helo();
4138 smtp_printf("%d %s argument does not match calling host\r\n", FALSE,
4139 tempfail? 451 : 550, hello);
4140 log_write(0, LOG_MAIN|LOG_REJECT, "%srejected \"%s %s\" from %s",
4141 tempfail? "temporarily " : "",
4142 hello, sender_helo_name, host_and_ident(FALSE));
4143 helo_verified = old_helo_verified;
4144 break; /* End of HELO/EHLO processing */
4146 HDEBUG(D_all) debug_printf("%s verification failed but host is in "
4147 "helo_try_verify_hosts\n", hello);
4153 /* set up SPF context */
4154 spf_init(sender_helo_name, sender_host_address);
4157 /* Apply an ACL check if one is defined; afterwards, recheck
4158 synchronization in case the client started sending in a delay. */
4161 if ((rc = acl_check(ACL_WHERE_HELO, NULL, acl_smtp_helo,
4162 &user_msg, &log_msg)) != OK)
4164 done = smtp_handle_acl_fail(ACL_WHERE_HELO, rc, user_msg, log_msg);
4165 if (sender_helo_name)
4167 store_free(sender_helo_name);
4168 sender_helo_name = NULL;
4170 host_build_sender_fullhost(); /* Rebuild */
4173 else if (!check_sync()) goto SYNC_FAILURE;
4175 /* Generate an OK reply. The default string includes the ident if present,
4176 and also the IP address if present. Reflecting back the ident is intended
4177 as a deterrent to mail forgers. For maximum efficiency, and also because
4178 some broken systems expect each response to be in a single packet, arrange
4179 that the entire reply is sent in one write(). */
4181 auth_advertised = FALSE;
4182 pipelining_advertised = FALSE;
4184 tls_advertised = FALSE;
4186 dsn_advertised = FALSE;
4188 smtputf8_advertised = FALSE;
4191 smtp_code = US"250 "; /* Default response code plus space*/
4194 s = string_sprintf("%.3s %s Hello %s%s%s",
4196 smtp_active_hostname,
4197 sender_ident ? sender_ident : US"",
4198 sender_ident ? US" at " : US"",
4199 sender_host_name ? sender_host_name : sender_helo_name);
4200 g = string_cat(NULL, s);
4202 if (sender_host_address)
4204 g = string_catn(g, US" [", 2);
4205 g = string_cat (g, sender_host_address);
4206 g = string_catn(g, US"]", 1);
4210 /* A user-supplied EHLO greeting may not contain more than one line. Note
4211 that the code returned by smtp_message_code() includes the terminating
4212 whitespace character. */
4218 smtp_message_code(&smtp_code, &codelen, &user_msg, NULL, TRUE);
4219 s = string_sprintf("%.*s%s", codelen, smtp_code, user_msg);
4220 if ((ss = strpbrk(CS s, "\r\n")) != NULL)
4222 log_write(0, LOG_MAIN|LOG_PANIC, "EHLO/HELO response must not contain "
4223 "newlines: message truncated: %s", string_printing(s));
4226 g = string_cat(NULL, s);
4229 g = string_catn(g, US"\r\n", 2);
4231 /* If we received EHLO, we must create a multiline response which includes
4232 the functions supported. */
4238 /* I'm not entirely happy with this, as an MTA is supposed to check
4239 that it has enough room to accept a message of maximum size before
4240 it sends this. However, there seems little point in not sending it.
4241 The actual size check happens later at MAIL FROM time. By postponing it
4242 till then, VRFY and EXPN can be used after EHLO when space is short. */
4244 if (thismessage_size_limit > 0)
4246 sprintf(CS big_buffer, "%.3s-SIZE %d\r\n", smtp_code,
4247 thismessage_size_limit);
4248 g = string_cat(g, big_buffer);
4252 g = string_catn(g, smtp_code, 3);
4253 g = string_catn(g, US"-SIZE\r\n", 7);
4256 /* Exim does not do protocol conversion or data conversion. It is 8-bit
4257 clean; if it has an 8-bit character in its hand, it just sends it. It
4258 cannot therefore specify 8BITMIME and remain consistent with the RFCs.
4259 However, some users want this option simply in order to stop MUAs
4260 mangling messages that contain top-bit-set characters. It is therefore
4261 provided as an option. */
4263 if (accept_8bitmime)
4265 g = string_catn(g, smtp_code, 3);
4266 g = string_catn(g, US"-8BITMIME\r\n", 11);
4269 /* Advertise DSN support if configured to do so. */
4270 if (verify_check_host(&dsn_advertise_hosts) != FAIL)
4272 g = string_catn(g, smtp_code, 3);
4273 g = string_catn(g, US"-DSN\r\n", 6);
4274 dsn_advertised = TRUE;
4277 /* Advertise ETRN/VRFY/EXPN if there's are ACL checking whether a host is
4278 permitted to issue them; a check is made when any host actually tries. */
4282 g = string_catn(g, smtp_code, 3);
4283 g = string_catn(g, US"-ETRN\r\n", 7);
4287 g = string_catn(g, smtp_code, 3);
4288 g = string_catn(g, US"-VRFY\r\n", 7);
4292 g = string_catn(g, smtp_code, 3);
4293 g = string_catn(g, US"-EXPN\r\n", 7);
4296 /* Exim is quite happy with pipelining, so let the other end know that
4297 it is safe to use it, unless advertising is disabled. */
4299 if (pipelining_enable &&
4300 verify_check_host(&pipelining_advertise_hosts) == OK)
4302 g = string_catn(g, smtp_code, 3);
4303 g = string_catn(g, US"-PIPELINING\r\n", 13);
4304 sync_cmd_limit = NON_SYNC_CMD_PIPELINING;
4305 pipelining_advertised = TRUE;
4309 /* If any server authentication mechanisms are configured, advertise
4310 them if the current host is in auth_advertise_hosts. The problem with
4311 advertising always is that some clients then require users to
4312 authenticate (and aren't configurable otherwise) even though it may not
4313 be necessary (e.g. if the host is in host_accept_relay).
4315 RFC 2222 states that SASL mechanism names contain only upper case
4316 letters, so output the names in upper case, though we actually recognize
4317 them in either case in the AUTH command. */
4321 && !sender_host_authenticated
4323 && verify_check_host(&auth_advertise_hosts) == OK
4328 for (au = auths; au; au = au->next)
4330 au->advertised = FALSE;
4333 DEBUG(D_auth+D_expand) debug_printf_indent(
4334 "Evaluating advertise_condition for %s athenticator\n",
4336 if ( !au->advertise_condition
4337 || expand_check_condition(au->advertise_condition, au->name,
4344 g = string_catn(g, smtp_code, 3);
4345 g = string_catn(g, US"-AUTH", 5);
4347 auth_advertised = TRUE;
4350 g = string_catn(g, US" ", 1);
4351 g = string_cat (g, au->public_name);
4352 while (++saveptr < g->ptr) g->s[saveptr] = toupper(g->s[saveptr]);
4353 au->advertised = TRUE;
4358 if (!first) g = string_catn(g, US"\r\n", 2);
4361 /* RFC 3030 CHUNKING */
4363 if (verify_check_host(&chunking_advertise_hosts) != FAIL)
4365 g = string_catn(g, smtp_code, 3);
4366 g = string_catn(g, US"-CHUNKING\r\n", 11);
4367 chunking_offered = TRUE;
4368 chunking_state = CHUNKING_OFFERED;
4371 /* Advertise TLS (Transport Level Security) aka SSL (Secure Socket Layer)
4372 if it has been included in the binary, and the host matches
4373 tls_advertise_hosts. We must *not* advertise if we are already in a
4374 secure connection. */
4377 if (tls_in.active < 0 &&
4378 verify_check_host(&tls_advertise_hosts) != FAIL)
4380 g = string_catn(g, smtp_code, 3);
4381 g = string_catn(g, US"-STARTTLS\r\n", 11);
4382 tls_advertised = TRUE;
4386 #ifndef DISABLE_PRDR
4387 /* Per Recipient Data Response, draft by Eric A. Hall extending RFC */
4390 g = string_catn(g, smtp_code, 3);
4391 g = string_catn(g, US"-PRDR\r\n", 7);
4396 if ( accept_8bitmime
4397 && verify_check_host(&smtputf8_advertise_hosts) != FAIL)
4399 g = string_catn(g, smtp_code, 3);
4400 g = string_catn(g, US"-SMTPUTF8\r\n", 11);
4401 smtputf8_advertised = TRUE;
4405 /* Finish off the multiline reply with one that is always available. */
4407 g = string_catn(g, smtp_code, 3);
4408 g = string_catn(g, US" HELP\r\n", 7);
4411 /* Terminate the string (for debug), write it, and note that HELO/EHLO
4415 if (tls_in.active >= 0) (void)tls_write(TRUE, g->s, g->ptr, FALSE); else
4419 int i = fwrite(g->s, 1, g->ptr, smtp_out); i = i; /* compiler quietening */
4425 (void) string_from_gstring(g);
4426 while ((cr = Ustrchr(g->s, '\r')) != NULL) /* lose CRs */
4427 memmove(cr, cr + 1, (g->ptr--) - (cr - g->s));
4428 debug_printf("SMTP>> %s", g->s);
4432 /* Reset the protocol and the state, abandoning any previous message. */
4434 (sender_host_address ? protocols : protocols_local)
4436 ? pextend + (sender_host_authenticated ? pauthed : 0)
4438 + (tls_in.active >= 0 ? pcrpted : 0)
4440 cancel_cutthrough_connection(TRUE, US"sent EHLO response");
4441 smtp_reset(reset_point);
4443 break; /* HELO/EHLO */
4446 /* The MAIL command requires an address as an operand. All we do
4447 here is to parse it for syntactic correctness. The form "<>" is
4448 a special case which converts into an empty string. The start/end
4449 pointers in the original are not used further for this address, as
4450 it is the canonical extracted address which is all that is kept. */
4454 smtp_mailcmd_count++; /* Count for limit and ratelimit */
4455 was_rej_mail = TRUE; /* Reset if accepted */
4456 env_mail_type_t * mail_args; /* Sanity check & validate args */
4458 if (helo_required && !helo_seen)
4460 smtp_printf("503 HELO or EHLO required\r\n", FALSE);
4461 log_write(0, LOG_MAIN|LOG_REJECT, "rejected MAIL from %s: no "
4462 "HELO/EHLO given", host_and_ident(FALSE));
4466 if (sender_address != NULL)
4468 done = synprot_error(L_smtp_protocol_error, 503, NULL,
4469 US"sender already given");
4473 if (smtp_cmd_data[0] == 0)
4475 done = synprot_error(L_smtp_protocol_error, 501, NULL,
4476 US"MAIL must have an address operand");
4480 /* Check to see if the limit for messages per connection would be
4481 exceeded by accepting further messages. */
4483 if (smtp_accept_max_per_connection > 0 &&
4484 smtp_mailcmd_count > smtp_accept_max_per_connection)
4486 smtp_printf("421 too many messages in this connection\r\n", FALSE);
4487 log_write(0, LOG_MAIN|LOG_REJECT, "rejected MAIL command %s: too many "
4488 "messages in one connection", host_and_ident(TRUE));
4492 /* Reset for start of message - even if this is going to fail, we
4493 obviously need to throw away any previous data. */
4495 cancel_cutthrough_connection(TRUE, US"MAIL received");
4496 smtp_reset(reset_point);
4498 sender_data = recipient_data = NULL;
4500 /* Loop, checking for ESMTP additions to the MAIL FROM command. */
4504 uschar *name, *value, *end;
4505 unsigned long int size;
4506 BOOL arg_error = FALSE;
4508 if (!extract_option(&name, &value)) break;
4510 for (mail_args = env_mail_type_list;
4511 mail_args->value != ENV_MAIL_OPT_NULL;
4514 if (strcmpic(name, mail_args->name) == 0)
4516 if (mail_args->need_value && strcmpic(value, US"") == 0)
4519 switch(mail_args->value)
4521 /* Handle SIZE= by reading the value. We don't do the check till later,
4522 in order to be able to log the sender address on failure. */
4523 case ENV_MAIL_OPT_SIZE:
4524 if (((size = Ustrtoul(value, &end, 10)), *end == 0))
4526 if ((size == ULONG_MAX && errno == ERANGE) || size > INT_MAX)
4528 message_size = (int)size;
4534 /* If this session was initiated with EHLO and accept_8bitmime is set,
4535 Exim will have indicated that it supports the BODY=8BITMIME option. In
4536 fact, it does not support this according to the RFCs, in that it does not
4537 take any special action for forwarding messages containing 8-bit
4538 characters. That is why accept_8bitmime is not the default setting, but
4539 some sites want the action that is provided. We recognize both "8BITMIME"
4540 and "7BIT" as body types, but take no action. */
4541 case ENV_MAIL_OPT_BODY:
4542 if (accept_8bitmime) {
4543 if (strcmpic(value, US"8BITMIME") == 0)
4545 else if (strcmpic(value, US"7BIT") == 0)
4550 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4551 US"invalid data for BODY");
4554 DEBUG(D_receive) debug_printf("8BITMIME: %d\n", body_8bitmime);
4560 /* Handle the two DSN options, but only if configured to do so (which
4561 will have caused "DSN" to be given in the EHLO response). The code itself
4562 is included only if configured in at build time. */
4564 case ENV_MAIL_OPT_RET:
4567 /* Check if RET has already been set */
4570 synprot_error(L_smtp_syntax_error, 501, NULL,
4571 US"RET can be specified once only");
4574 dsn_ret = strcmpic(value, US"HDRS") == 0
4576 : strcmpic(value, US"FULL") == 0
4579 DEBUG(D_receive) debug_printf("DSN_RET: %d\n", dsn_ret);
4580 /* Check for invalid invalid value, and exit with error */
4583 synprot_error(L_smtp_syntax_error, 501, NULL,
4584 US"Value for RET is invalid");
4589 case ENV_MAIL_OPT_ENVID:
4592 /* Check if the dsn envid has been already set */
4593 if (dsn_envid != NULL)
4595 synprot_error(L_smtp_syntax_error, 501, NULL,
4596 US"ENVID can be specified once only");
4599 dsn_envid = string_copy(value);
4600 DEBUG(D_receive) debug_printf("DSN_ENVID: %s\n", dsn_envid);
4604 /* Handle the AUTH extension. If the value given is not "<>" and either
4605 the ACL says "yes" or there is no ACL but the sending host is
4606 authenticated, we set it up as the authenticated sender. However, if the
4607 authenticator set a condition to be tested, we ignore AUTH on MAIL unless
4608 the condition is met. The value of AUTH is an xtext, which means that +,
4609 = and cntrl chars are coded in hex; however "<>" is unaffected by this
4611 case ENV_MAIL_OPT_AUTH:
4612 if (Ustrcmp(value, "<>") != 0)
4617 if (auth_xtextdecode(value, &authenticated_sender) < 0)
4619 /* Put back terminator overrides for error message */
4622 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4623 US"invalid data for AUTH");
4626 if (!acl_smtp_mailauth)
4628 ignore_msg = US"client not authenticated";
4629 rc = sender_host_authenticated ? OK : FAIL;
4633 ignore_msg = US"rejected by ACL";
4634 rc = acl_check(ACL_WHERE_MAILAUTH, NULL, acl_smtp_mailauth,
4635 &user_msg, &log_msg);
4641 if (authenticated_by == NULL ||
4642 authenticated_by->mail_auth_condition == NULL ||
4643 expand_check_condition(authenticated_by->mail_auth_condition,
4644 authenticated_by->name, US"authenticator"))
4645 break; /* Accept the AUTH */
4647 ignore_msg = US"server_mail_auth_condition failed";
4648 if (authenticated_id != NULL)
4649 ignore_msg = string_sprintf("%s: authenticated ID=\"%s\"",
4650 ignore_msg, authenticated_id);
4655 authenticated_sender = NULL;
4656 log_write(0, LOG_MAIN, "ignoring AUTH=%s from %s (%s)",
4657 value, host_and_ident(TRUE), ignore_msg);
4660 /* Should only get DEFER or ERROR here. Put back terminator
4661 overrides for error message */
4666 (void)smtp_handle_acl_fail(ACL_WHERE_MAILAUTH, rc, user_msg,
4673 #ifndef DISABLE_PRDR
4674 case ENV_MAIL_OPT_PRDR:
4676 prdr_requested = TRUE;
4681 case ENV_MAIL_OPT_UTF8:
4682 if (smtputf8_advertised)
4684 int old_pool = store_pool;
4686 DEBUG(D_receive) debug_printf("smtputf8 requested\n");
4687 message_smtputf8 = allow_utf8_domains = TRUE;
4688 store_pool = POOL_PERM;
4689 received_protocol = string_sprintf("utf8%s", received_protocol);
4690 store_pool = old_pool;
4694 /* No valid option. Stick back the terminator characters and break
4695 the loop. Do the name-terminator second as extract_option sets
4696 value==name when it found no equal-sign.
4697 An error for a malformed address will occur. */
4698 case ENV_MAIL_OPT_NULL:
4706 /* Break out of for loop if switch() had bad argument or
4707 when start of the email address is reached */
4708 if (arg_error) break;
4711 /* If we have passed the threshold for rate limiting, apply the current
4712 delay, and update it for next time, provided this is a limited host. */
4714 if (smtp_mailcmd_count > smtp_rlm_threshold &&
4715 verify_check_host(&smtp_ratelimit_hosts) == OK)
4717 DEBUG(D_receive) debug_printf("rate limit MAIL: delay %.3g sec\n",
4718 smtp_delay_mail/1000.0);
4719 millisleep((int)smtp_delay_mail);
4720 smtp_delay_mail *= smtp_rlm_factor;
4721 if (smtp_delay_mail > (double)smtp_rlm_limit)
4722 smtp_delay_mail = (double)smtp_rlm_limit;
4725 /* Now extract the address, first applying any SMTP-time rewriting. The
4726 TRUE flag allows "<>" as a sender address. */
4728 raw_sender = rewrite_existflags & rewrite_smtp
4729 ? rewrite_one(smtp_cmd_data, rewrite_smtp, NULL, FALSE, US"",
4730 global_rewrite_rules)
4734 parse_extract_address(raw_sender, &errmess, &start, &end, &sender_domain,
4739 done = synprot_error(L_smtp_syntax_error, 501, smtp_cmd_data, errmess);
4743 sender_address = raw_sender;
4745 /* If there is a configured size limit for mail, check that this message
4746 doesn't exceed it. The check is postponed to this point so that the sender
4749 if (thismessage_size_limit > 0 && message_size > thismessage_size_limit)
4751 smtp_printf("552 Message size exceeds maximum permitted\r\n", FALSE);
4752 log_write(L_size_reject,
4753 LOG_MAIN|LOG_REJECT, "rejected MAIL FROM:<%s> %s: "
4754 "message too big: size%s=%d max=%d",
4756 host_and_ident(TRUE),
4757 (message_size == INT_MAX)? ">" : "",
4759 thismessage_size_limit);
4760 sender_address = NULL;
4764 /* Check there is enough space on the disk unless configured not to.
4765 When smtp_check_spool_space is set, the check is for thismessage_size_limit
4766 plus the current message - i.e. we accept the message only if it won't
4767 reduce the space below the threshold. Add 5000 to the size to allow for
4768 overheads such as the Received: line and storing of recipients, etc.
4769 By putting the check here, even when SIZE is not given, it allow VRFY
4770 and EXPN etc. to be used when space is short. */
4772 if (!receive_check_fs(
4773 (smtp_check_spool_space && message_size >= 0)?
4774 message_size + 5000 : 0))
4776 smtp_printf("452 Space shortage, please try later\r\n", FALSE);
4777 sender_address = NULL;
4781 /* If sender_address is unqualified, reject it, unless this is a locally
4782 generated message, or the sending host or net is permitted to send
4783 unqualified addresses - typically local machines behaving as MUAs -
4784 in which case just qualify the address. The flag is set above at the start
4785 of the SMTP connection. */
4787 if (sender_domain == 0 && sender_address[0] != 0)
4789 if (allow_unqualified_sender)
4791 sender_domain = Ustrlen(sender_address) + 1;
4792 sender_address = rewrite_address_qualify(sender_address, FALSE);
4793 DEBUG(D_receive) debug_printf("unqualified address %s accepted\n",
4798 smtp_printf("501 %s: sender address must contain a domain\r\n", FALSE,
4800 log_write(L_smtp_syntax_error,
4801 LOG_MAIN|LOG_REJECT,
4802 "unqualified sender rejected: <%s> %s%s",
4804 host_and_ident(TRUE),
4806 sender_address = NULL;
4811 /* Apply an ACL check if one is defined, before responding. Afterwards,
4812 when pipelining is not advertised, do another sync check in case the ACL
4813 delayed and the client started sending in the meantime. */
4817 rc = acl_check(ACL_WHERE_MAIL, NULL, acl_smtp_mail, &user_msg, &log_msg);
4818 if (rc == OK && !pipelining_advertised && !check_sync())
4824 if (rc == OK || rc == DISCARD)
4826 BOOL more = pipeline_response();
4829 smtp_printf("%s%s%s", more, US"250 OK",
4830 #ifndef DISABLE_PRDR
4831 prdr_requested ? US", PRDR Requested" : US"",
4838 #ifndef DISABLE_PRDR
4840 user_msg = string_sprintf("%s%s", user_msg, US", PRDR Requested");
4842 smtp_user_msg(US"250", user_msg);
4844 smtp_delay_rcpt = smtp_rlr_base;
4845 recipients_discarded = (rc == DISCARD);
4846 was_rej_mail = FALSE;
4850 done = smtp_handle_acl_fail(ACL_WHERE_MAIL, rc, user_msg, log_msg);
4851 sender_address = NULL;
4856 /* The RCPT command requires an address as an operand. There may be any
4857 number of RCPT commands, specifying multiple recipients. We build them all
4858 into a data structure. The start/end values given by parse_extract_address
4859 are not used, as we keep only the extracted address. */
4864 was_rcpt = rcpt_in_progress = TRUE;
4866 /* There must be a sender address; if the sender was rejected and
4867 pipelining was advertised, we assume the client was pipelining, and do not
4868 count this as a protocol error. Reset was_rej_mail so that further RCPTs
4869 get the same treatment. */
4871 if (sender_address == NULL)
4873 if (pipelining_advertised && last_was_rej_mail)
4875 smtp_printf("503 sender not yet given\r\n", FALSE);
4876 was_rej_mail = TRUE;
4880 done = synprot_error(L_smtp_protocol_error, 503, NULL,
4881 US"sender not yet given");
4882 was_rcpt = FALSE; /* Not a valid RCPT */
4888 /* Check for an operand */
4890 if (smtp_cmd_data[0] == 0)
4892 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4893 US"RCPT must have an address operand");
4898 /* Set the DSN flags orcpt and dsn_flags from the session*/
4904 uschar *name, *value;
4906 if (!extract_option(&name, &value))
4909 if (dsn_advertised && strcmpic(name, US"ORCPT") == 0)
4911 /* Check whether orcpt has been already set */
4914 synprot_error(L_smtp_syntax_error, 501, NULL,
4915 US"ORCPT can be specified once only");
4918 orcpt = string_copy(value);
4919 DEBUG(D_receive) debug_printf("DSN orcpt: %s\n", orcpt);
4922 else if (dsn_advertised && strcmpic(name, US"NOTIFY") == 0)
4924 /* Check if the notify flags have been already set */
4927 synprot_error(L_smtp_syntax_error, 501, NULL,
4928 US"NOTIFY can be specified once only");
4931 if (strcmpic(value, US"NEVER") == 0)
4932 flags |= rf_notify_never;
4939 while (*pp != 0 && *pp != ',') pp++;
4940 if (*pp == ',') *pp++ = 0;
4941 if (strcmpic(p, US"SUCCESS") == 0)
4943 DEBUG(D_receive) debug_printf("DSN: Setting notify success\n");
4944 flags |= rf_notify_success;
4946 else if (strcmpic(p, US"FAILURE") == 0)
4948 DEBUG(D_receive) debug_printf("DSN: Setting notify failure\n");
4949 flags |= rf_notify_failure;
4951 else if (strcmpic(p, US"DELAY") == 0)
4953 DEBUG(D_receive) debug_printf("DSN: Setting notify delay\n");
4954 flags |= rf_notify_delay;
4958 /* Catch any strange values */
4959 synprot_error(L_smtp_syntax_error, 501, NULL,
4960 US"Invalid value for NOTIFY parameter");
4965 DEBUG(D_receive) debug_printf("DSN Flags: %x\n", flags);
4969 /* Unknown option. Stick back the terminator characters and break
4970 the loop. An error for a malformed address will occur. */
4974 DEBUG(D_receive) debug_printf("Invalid RCPT option: %s : %s\n", name, value);
4981 /* Apply SMTP rewriting then extract the working address. Don't allow "<>"
4982 as a recipient address */
4984 recipient = rewrite_existflags & rewrite_smtp
4985 ? rewrite_one(smtp_cmd_data, rewrite_smtp, NULL, FALSE, US"",
4986 global_rewrite_rules)
4989 if (!(recipient = parse_extract_address(recipient, &errmess, &start, &end,
4990 &recipient_domain, FALSE)))
4992 done = synprot_error(L_smtp_syntax_error, 501, smtp_cmd_data, errmess);
4997 /* If the recipient address is unqualified, reject it, unless this is a
4998 locally generated message. However, unqualified addresses are permitted
4999 from a configured list of hosts and nets - typically when behaving as
5000 MUAs rather than MTAs. Sad that SMTP is used for both types of traffic,
5001 really. The flag is set at the start of the SMTP connection.
5003 RFC 1123 talks about supporting "the reserved mailbox postmaster"; I always
5004 assumed this meant "reserved local part", but the revision of RFC 821 and
5005 friends now makes it absolutely clear that it means *mailbox*. Consequently
5006 we must always qualify this address, regardless. */
5008 if (!recipient_domain)
5009 if (!(recipient_domain = qualify_recipient(&recipient, smtp_cmd_data,
5016 /* Check maximum allowed */
5018 if (rcpt_count > recipients_max && recipients_max > 0)
5020 if (recipients_max_reject)
5023 smtp_printf("552 too many recipients\r\n", FALSE);
5025 log_write(0, LOG_MAIN|LOG_REJECT, "too many recipients: message "
5026 "rejected: sender=<%s> %s", sender_address, host_and_ident(TRUE));
5031 smtp_printf("452 too many recipients\r\n", FALSE);
5033 log_write(0, LOG_MAIN|LOG_REJECT, "too many recipients: excess "
5034 "temporarily rejected: sender=<%s> %s", sender_address,
5035 host_and_ident(TRUE));
5042 /* If we have passed the threshold for rate limiting, apply the current
5043 delay, and update it for next time, provided this is a limited host. */
5045 if (rcpt_count > smtp_rlr_threshold &&
5046 verify_check_host(&smtp_ratelimit_hosts) == OK)
5048 DEBUG(D_receive) debug_printf("rate limit RCPT: delay %.3g sec\n",
5049 smtp_delay_rcpt/1000.0);
5050 millisleep((int)smtp_delay_rcpt);
5051 smtp_delay_rcpt *= smtp_rlr_factor;
5052 if (smtp_delay_rcpt > (double)smtp_rlr_limit)
5053 smtp_delay_rcpt = (double)smtp_rlr_limit;
5056 /* If the MAIL ACL discarded all the recipients, we bypass ACL checking
5057 for them. Otherwise, check the access control list for this recipient. As
5058 there may be a delay in this, re-check for a synchronization error
5059 afterwards, unless pipelining was advertised. */
5061 if (recipients_discarded)
5064 if ( (rc = acl_check(ACL_WHERE_RCPT, recipient, acl_smtp_rcpt, &user_msg,
5066 && !pipelining_advertised && !check_sync())
5069 /* The ACL was happy */
5073 BOOL more = pipeline_response();
5076 smtp_user_msg(US"250", user_msg);
5078 smtp_printf("250 Accepted\r\n", more);
5079 receive_add_recipient(recipient, -1);
5081 /* Set the dsn flags in the recipients_list */
5082 recipients_list[recipients_count-1].orcpt = orcpt;
5083 recipients_list[recipients_count-1].dsn_flags = flags;
5085 DEBUG(D_receive) debug_printf("DSN: orcpt: %s flags: %d\n",
5086 recipients_list[recipients_count-1].orcpt,
5087 recipients_list[recipients_count-1].dsn_flags);
5090 /* The recipient was discarded */
5092 else if (rc == DISCARD)
5095 smtp_user_msg(US"250", user_msg);
5097 smtp_printf("250 Accepted\r\n", FALSE);
5100 log_write(0, LOG_MAIN|LOG_REJECT, "%s F=<%s> RCPT %s: "
5101 "discarded by %s ACL%s%s", host_and_ident(TRUE),
5102 sender_address_unrewritten? sender_address_unrewritten : sender_address,
5103 smtp_cmd_argument, recipients_discarded? "MAIL" : "RCPT",
5104 log_msg ? US": " : US"", log_msg ? log_msg : US"");
5107 /* Either the ACL failed the address, or it was deferred. */
5111 if (rc == FAIL) rcpt_fail_count++; else rcpt_defer_count++;
5112 done = smtp_handle_acl_fail(ACL_WHERE_RCPT, rc, user_msg, log_msg);
5117 /* The DATA command is legal only if it follows successful MAIL FROM
5118 and RCPT TO commands. However, if pipelining is advertised, a bad DATA is
5119 not counted as a protocol error if it follows RCPT (which must have been
5120 rejected if there are no recipients.) This function is complete when a
5121 valid DATA command is encountered.
5123 Note concerning the code used: RFC 2821 says this:
5125 - If there was no MAIL, or no RCPT, command, or all such commands
5126 were rejected, the server MAY return a "command out of sequence"
5127 (503) or "no valid recipients" (554) reply in response to the
5130 The example in the pipelining RFC 2920 uses 554, but I use 503 here
5131 because it is the same whether pipelining is in use or not.
5133 If all the RCPT commands that precede DATA provoked the same error message
5134 (often indicating some kind of system error), it is helpful to include it
5135 with the DATA rejection (an idea suggested by Tony Finch). */
5142 if (chunking_state != CHUNKING_OFFERED)
5144 done = synprot_error(L_smtp_protocol_error, 503, NULL,
5145 US"BDAT command used when CHUNKING not advertised");
5149 /* grab size, endmarker */
5151 if (sscanf(CS smtp_cmd_data, "%u %n", &chunking_datasize, &n) < 1)
5153 done = synprot_error(L_smtp_protocol_error, 501, NULL,
5154 US"missing size for BDAT command");
5157 chunking_state = strcmpic(smtp_cmd_data+n, US"LAST") == 0
5158 ? CHUNKING_LAST : CHUNKING_ACTIVE;
5159 chunking_data_left = chunking_datasize;
5160 DEBUG(D_receive) debug_printf("chunking state %d, %d bytes\n",
5161 (int)chunking_state, chunking_data_left);
5163 /* push the current receive_* function on the "stack", and
5164 replace them by bdat_getc(), which in turn will use the lwr_receive_*
5165 functions to do the dirty work. */
5166 lwr_receive_getc = receive_getc;
5167 lwr_receive_getbuf = receive_getbuf;
5168 lwr_receive_ungetc = receive_ungetc;
5170 receive_getc = bdat_getc;
5171 receive_ungetc = bdat_ungetc;
5182 DATA_BDAT: /* Common code for DATA and BDAT */
5183 if (!discarded && recipients_count <= 0)
5185 if (rcpt_smtp_response_same && rcpt_smtp_response != NULL)
5187 uschar *code = US"503";
5188 int len = Ustrlen(rcpt_smtp_response);
5189 smtp_respond(code, 3, FALSE, US"All RCPT commands were rejected with "
5191 /* Responses from smtp_printf() will have \r\n on the end */
5192 if (len > 2 && rcpt_smtp_response[len-2] == '\r')
5193 rcpt_smtp_response[len-2] = 0;
5194 smtp_respond(code, 3, FALSE, rcpt_smtp_response);
5196 if (pipelining_advertised && last_was_rcpt)
5197 smtp_printf("503 Valid RCPT command must precede %s\r\n", FALSE,
5198 smtp_names[smtp_connection_had[smtp_ch_index-1]]);
5200 done = synprot_error(L_smtp_protocol_error, 503, NULL,
5201 smtp_connection_had[smtp_ch_index-1] == SCH_DATA
5202 ? US"valid RCPT command must precede DATA"
5203 : US"valid RCPT command must precede BDAT");
5205 if (chunking_state > CHUNKING_OFFERED)
5210 if (toomany && recipients_max_reject)
5212 sender_address = NULL; /* This will allow a new MAIL without RSET */
5213 sender_address_unrewritten = NULL;
5214 smtp_printf("554 Too many recipients\r\n", FALSE);
5218 if (chunking_state > CHUNKING_OFFERED)
5219 rc = OK; /* No predata ACL or go-ahead output for BDAT */
5222 /* If there is an ACL, re-check the synchronization afterwards, since the
5223 ACL may have delayed. To handle cutthrough delivery enforce a dummy call
5224 to get the DATA command sent. */
5226 if (acl_smtp_predata == NULL && cutthrough.fd < 0)
5230 uschar * acl = acl_smtp_predata ? acl_smtp_predata : US"accept";
5231 enable_dollar_recipients = TRUE;
5232 rc = acl_check(ACL_WHERE_PREDATA, NULL, acl, &user_msg,
5234 enable_dollar_recipients = FALSE;
5235 if (rc == OK && !check_sync())
5239 { /* Either the ACL failed the address, or it was deferred. */
5240 done = smtp_handle_acl_fail(ACL_WHERE_PREDATA, rc, user_msg, log_msg);
5246 smtp_user_msg(US"354", user_msg);
5249 "354 Enter message, ending with \".\" on a line by itself\r\n", FALSE);
5253 if (smtp_in) /* all ACKs needed to ramp window up for bulk data */
5254 (void) setsockopt(fileno(smtp_in), IPPROTO_TCP, TCP_QUICKACK,
5255 US &on, sizeof(on));
5258 message_ended = END_NOTENDED; /* Indicate in middle of data */
5269 if (!(address = parse_extract_address(smtp_cmd_data, &errmess,
5270 &start, &end, &recipient_domain, FALSE)))
5272 smtp_printf("501 %s\r\n", FALSE, errmess);
5276 if (!recipient_domain)
5277 if (!(recipient_domain = qualify_recipient(&address, smtp_cmd_data,
5281 if ((rc = acl_check(ACL_WHERE_VRFY, address, acl_smtp_vrfy,
5282 &user_msg, &log_msg)) != OK)
5283 done = smtp_handle_acl_fail(ACL_WHERE_VRFY, rc, user_msg, log_msg);
5287 address_item * addr = deliver_make_addr(address, FALSE);
5289 switch(verify_address(addr, NULL, vopt_is_recipient | vopt_qualify, -1,
5290 -1, -1, NULL, NULL, NULL))
5293 s = string_sprintf("250 <%s> is deliverable", address);
5297 s = (addr->user_message != NULL)?
5298 string_sprintf("451 <%s> %s", address, addr->user_message) :
5299 string_sprintf("451 Cannot resolve <%s> at this time", address);
5303 s = (addr->user_message != NULL)?
5304 string_sprintf("550 <%s> %s", address, addr->user_message) :
5305 string_sprintf("550 <%s> is not deliverable", address);
5306 log_write(0, LOG_MAIN, "VRFY failed for %s %s",
5307 smtp_cmd_argument, host_and_ident(TRUE));
5311 smtp_printf("%s\r\n", FALSE, s);
5319 rc = acl_check(ACL_WHERE_EXPN, NULL, acl_smtp_expn, &user_msg, &log_msg);
5321 done = smtp_handle_acl_fail(ACL_WHERE_EXPN, rc, user_msg, log_msg);
5324 BOOL save_log_testing_mode = log_testing_mode;
5325 address_test_mode = log_testing_mode = TRUE;
5326 (void) verify_address(deliver_make_addr(smtp_cmd_data, FALSE),
5327 smtp_out, vopt_is_recipient | vopt_qualify | vopt_expn, -1, -1, -1,
5329 address_test_mode = FALSE;
5330 log_testing_mode = save_log_testing_mode; /* true for -bh */
5339 if (!tls_advertised)
5341 done = synprot_error(L_smtp_protocol_error, 503, NULL,
5342 US"STARTTLS command used when not advertised");
5346 /* Apply an ACL check if one is defined */
5348 if ( acl_smtp_starttls
5349 && (rc = acl_check(ACL_WHERE_STARTTLS, NULL, acl_smtp_starttls,
5350 &user_msg, &log_msg)) != OK
5353 done = smtp_handle_acl_fail(ACL_WHERE_STARTTLS, rc, user_msg, log_msg);
5357 /* RFC 2487 is not clear on when this command may be sent, though it
5358 does state that all information previously obtained from the client
5359 must be discarded if a TLS session is started. It seems reasonable to
5360 do an implied RSET when STARTTLS is received. */
5362 incomplete_transaction_log(US"STARTTLS");
5363 cancel_cutthrough_connection(TRUE, US"STARTTLS received");
5364 smtp_reset(reset_point);
5366 cmd_list[CMD_LIST_STARTTLS].is_mail_cmd = FALSE;
5368 /* There's an attack where more data is read in past the STARTTLS command
5369 before TLS is negotiated, then assumed to be part of the secure session
5370 when used afterwards; we use segregated input buffers, so are not
5371 vulnerable, but we want to note when it happens and, for sheer paranoia,
5372 ensure that the buffer is "wiped".
5373 Pipelining sync checks will normally have protected us too, unless disabled
5374 by configuration. */
5376 if (receive_smtp_buffered())
5379 debug_printf("Non-empty input buffer after STARTTLS; naive attack?\n");
5380 if (tls_in.active < 0)
5381 smtp_inend = smtp_inptr = smtp_inbuffer;
5382 /* and if TLS is already active, tls_server_start() should fail */
5385 /* There is nothing we value in the input buffer and if TLS is successfully
5386 negotiated, we won't use this buffer again; if TLS fails, we'll just read
5387 fresh content into it. The buffer contains arbitrary content from an
5388 untrusted remote source; eg: NOOP <shellcode>\r\nSTARTTLS\r\n
5389 It seems safest to just wipe away the content rather than leave it as a
5390 target to jump to. */
5392 memset(smtp_inbuffer, 0, IN_BUFFER_SIZE);
5394 /* Attempt to start up a TLS session, and if successful, discard all
5395 knowledge that was obtained previously. At least, that's what the RFC says,
5396 and that's what happens by default. However, in order to work round YAEB,
5397 there is an option to remember the esmtp state. Sigh.
5399 We must allow for an extra EHLO command and an extra AUTH command after
5400 STARTTLS that don't add to the nonmail command count. */
5403 if ((rc = tls_server_start(tls_require_ciphers, &s)) == OK)
5405 if (!tls_remember_esmtp)
5406 helo_seen = esmtp = auth_advertised = pipelining_advertised = FALSE;
5407 cmd_list[CMD_LIST_EHLO].is_mail_cmd = TRUE;
5408 cmd_list[CMD_LIST_AUTH].is_mail_cmd = TRUE;
5409 cmd_list[CMD_LIST_TLS_AUTH].is_mail_cmd = TRUE;
5410 if (sender_helo_name)
5412 store_free(sender_helo_name);
5413 sender_helo_name = NULL;
5414 host_build_sender_fullhost(); /* Rebuild */
5415 set_process_info("handling incoming TLS connection from %s",
5416 host_and_ident(FALSE));
5419 (sender_host_address ? protocols : protocols_local)
5421 ? pextend + (sender_host_authenticated ? pauthed : 0)
5423 + (tls_in.active >= 0 ? pcrpted : 0)
5426 sender_host_auth_pubname = sender_host_authenticated = NULL;
5427 authenticated_id = NULL;
5428 sync_cmd_limit = NON_SYNC_CMD_NON_PIPELINING;
5429 DEBUG(D_tls) debug_printf("TLS active\n");
5430 break; /* Successful STARTTLS */
5433 (void) smtp_log_tls_fail(s);
5435 /* Some local configuration problem was discovered before actually trying
5436 to do a TLS handshake; give a temporary error. */
5440 smtp_printf("454 TLS currently unavailable\r\n", FALSE);
5444 /* Hard failure. Reject everything except QUIT or closed connection. One
5445 cause for failure is a nested STARTTLS, in which case tls_in.active remains
5446 set, but we must still reject all incoming commands. */
5448 DEBUG(D_tls) debug_printf("TLS failed to start\n");
5449 while (done <= 0) switch(smtp_read_command(FALSE, GETC_BUFFER_UNLIMITED))
5452 log_write(L_smtp_connection, LOG_MAIN, "%s closed by EOF",
5453 smtp_get_connection_info());
5454 smtp_notquit_exit(US"tls-failed", NULL, NULL);
5458 /* It is perhaps arguable as to which exit ACL should be called here,
5459 but as it is probably a situation that almost never arises, it
5460 probably doesn't matter. We choose to call the real QUIT ACL, which in
5461 some sense is perhaps "right". */
5466 && ((rc = acl_check(ACL_WHERE_QUIT, NULL, acl_smtp_quit, &user_msg,
5467 &log_msg)) == ERROR))
5468 log_write(0, LOG_MAIN|LOG_PANIC, "ACL for QUIT returned ERROR: %s",
5471 smtp_respond(US"221", 3, TRUE, user_msg);
5473 smtp_printf("221 %s closing connection\r\n", FALSE, smtp_active_hostname);
5474 log_write(L_smtp_connection, LOG_MAIN, "%s closed by QUIT",
5475 smtp_get_connection_info());
5480 smtp_printf("554 Security failure\r\n", FALSE);
5483 tls_close(TRUE, TLS_SHUTDOWN_NOWAIT);
5488 /* The ACL for QUIT is provided for gathering statistical information or
5489 similar; it does not affect the response code, but it can supply a custom
5493 smtp_quit_handler(&user_msg, &log_msg);
5499 smtp_rset_handler();
5500 cancel_cutthrough_connection(TRUE, US"RSET received");
5501 smtp_reset(reset_point);
5508 smtp_printf("250 OK\r\n", FALSE);
5512 /* Show ETRN/EXPN/VRFY if there's an ACL for checking hosts; if actually
5513 used, a check will be done for permitted hosts. Show STARTTLS only if not
5514 already in a TLS session and if it would be advertised in the EHLO
5519 smtp_printf("214-Commands supported:\r\n", TRUE);
5523 Ustrcat(buffer, " AUTH");
5525 if (tls_in.active < 0 &&
5526 verify_check_host(&tls_advertise_hosts) != FAIL)
5527 Ustrcat(buffer, " STARTTLS");
5529 Ustrcat(buffer, " HELO EHLO MAIL RCPT DATA BDAT");
5530 Ustrcat(buffer, " NOOP QUIT RSET HELP");
5531 if (acl_smtp_etrn != NULL) Ustrcat(buffer, " ETRN");
5532 if (acl_smtp_expn != NULL) Ustrcat(buffer, " EXPN");
5533 if (acl_smtp_vrfy != NULL) Ustrcat(buffer, " VRFY");
5534 smtp_printf("214%s\r\n", FALSE, buffer);
5540 incomplete_transaction_log(US"connection lost");
5541 smtp_notquit_exit(US"connection-lost", US"421",
5542 US"%s lost input connection", smtp_active_hostname);
5544 /* Don't log by default unless in the middle of a message, as some mailers
5545 just drop the call rather than sending QUIT, and it clutters up the logs.
5548 if (sender_address || recipients_count > 0)
5549 log_write(L_lost_incoming_connection, LOG_MAIN,
5550 "unexpected %s while reading SMTP command from %s%s%s D=%s",
5551 sender_host_unknown ? "EOF" : "disconnection",
5552 tcp_in_fastopen && !tcp_in_fastopen_logged ? US"TFO " : US"",
5553 host_and_ident(FALSE), smtp_read_error,
5554 string_timesince(&smtp_connection_start)
5558 log_write(L_smtp_connection, LOG_MAIN, "%s %slost%s D=%s",
5559 smtp_get_connection_info(),
5560 tcp_in_fastopen && !tcp_in_fastopen_logged ? US"TFO " : US"",
5562 string_timesince(&smtp_connection_start)
5573 done = synprot_error(L_smtp_protocol_error, 503, NULL,
5574 US"ETRN is not permitted inside a transaction");
5578 log_write(L_etrn, LOG_MAIN, "ETRN %s received from %s", smtp_cmd_argument,
5579 host_and_ident(FALSE));
5581 if ((rc = acl_check(ACL_WHERE_ETRN, NULL, acl_smtp_etrn,
5582 &user_msg, &log_msg)) != OK)
5584 done = smtp_handle_acl_fail(ACL_WHERE_ETRN, rc, user_msg, log_msg);
5588 /* Compute the serialization key for this command. */
5590 etrn_serialize_key = string_sprintf("etrn-%s\n", smtp_cmd_data);
5592 /* If a command has been specified for running as a result of ETRN, we
5593 permit any argument to ETRN. If not, only the # standard form is permitted,
5594 since that is strictly the only kind of ETRN that can be implemented
5595 according to the RFC. */
5597 if (smtp_etrn_command)
5601 etrn_command = smtp_etrn_command;
5602 deliver_domain = smtp_cmd_data;
5603 rc = transport_set_up_command(&argv, smtp_etrn_command, TRUE, 0, NULL,
5604 US"ETRN processing", &error);
5605 deliver_domain = NULL;
5608 log_write(0, LOG_MAIN|LOG_PANIC, "failed to set up ETRN command: %s",
5610 smtp_printf("458 Internal failure\r\n", FALSE);
5615 /* Else set up to call Exim with the -R option. */
5619 if (*smtp_cmd_data++ != '#')
5621 done = synprot_error(L_smtp_syntax_error, 501, NULL,
5622 US"argument must begin with #");
5625 etrn_command = US"exim -R";
5626 argv = CUSS child_exec_exim(CEE_RETURN_ARGV, TRUE, NULL, TRUE,
5627 *queue_name ? 4 : 2,
5628 US"-R", smtp_cmd_data,
5629 US"-MCG", queue_name);
5632 /* If we are host-testing, don't actually do anything. */
5638 debug_printf("ETRN command is: %s\n", etrn_command);
5639 debug_printf("ETRN command execution skipped\n");
5641 if (user_msg == NULL) smtp_printf("250 OK\r\n", FALSE);
5642 else smtp_user_msg(US"250", user_msg);
5647 /* If ETRN queue runs are to be serialized, check the database to
5648 ensure one isn't already running. */
5650 if (smtp_etrn_serialize && !enq_start(etrn_serialize_key, 1))
5652 smtp_printf("458 Already processing %s\r\n", FALSE, smtp_cmd_data);
5656 /* Fork a child process and run the command. We don't want to have to
5657 wait for the process at any point, so set SIGCHLD to SIG_IGN before
5658 forking. It should be set that way anyway for external incoming SMTP,
5659 but we save and restore to be tidy. If serialization is required, we
5660 actually run the command in yet another process, so we can wait for it
5661 to complete and then remove the serialization lock. */
5663 oldsignal = signal(SIGCHLD, SIG_IGN);
5665 if ((pid = fork()) == 0)
5667 smtp_input = FALSE; /* This process is not associated with the */
5668 (void)fclose(smtp_in); /* SMTP call any more. */
5669 (void)fclose(smtp_out);
5671 signal(SIGCHLD, SIG_DFL); /* Want to catch child */
5673 /* If not serializing, do the exec right away. Otherwise, fork down
5674 into another process. */
5676 if (!smtp_etrn_serialize || (pid = fork()) == 0)
5678 DEBUG(D_exec) debug_print_argv(argv);
5679 exim_nullstd(); /* Ensure std{in,out,err} exist */
5680 execv(CS argv[0], (char *const *)argv);
5681 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "exec of \"%s\" (ETRN) failed: %s",
5682 etrn_command, strerror(errno));
5683 _exit(EXIT_FAILURE); /* paranoia */
5686 /* Obey this if smtp_serialize and the 2nd fork yielded non-zero. That
5687 is, we are in the first subprocess, after forking again. All we can do
5688 for a failing fork is to log it. Otherwise, wait for the 2nd process to
5689 complete, before removing the serialization. */
5692 log_write(0, LOG_MAIN|LOG_PANIC, "2nd fork for serialized ETRN "
5693 "failed: %s", strerror(errno));
5697 DEBUG(D_any) debug_printf("waiting for serialized ETRN process %d\n",
5699 (void)wait(&status);
5700 DEBUG(D_any) debug_printf("serialized ETRN process %d ended\n",
5704 enq_end(etrn_serialize_key);
5705 _exit(EXIT_SUCCESS);
5708 /* Back in the top level SMTP process. Check that we started a subprocess
5709 and restore the signal state. */
5713 log_write(0, LOG_MAIN|LOG_PANIC, "fork of process for ETRN failed: %s",
5715 smtp_printf("458 Unable to fork process\r\n", FALSE);
5716 if (smtp_etrn_serialize) enq_end(etrn_serialize_key);
5720 if (user_msg == NULL) smtp_printf("250 OK\r\n", FALSE);
5721 else smtp_user_msg(US"250", user_msg);
5724 signal(SIGCHLD, oldsignal);
5729 done = synprot_error(L_smtp_syntax_error, 501, NULL,
5730 US"unexpected argument data");
5734 /* This currently happens only for NULLs, but could be extended. */
5737 done = synprot_error(L_smtp_syntax_error, 0, NULL, /* Just logs */
5738 US"NUL character(s) present (shown as '?')");
5739 smtp_printf("501 NUL characters are not allowed in SMTP commands\r\n", FALSE);
5745 if (smtp_inend >= smtp_inbuffer + IN_BUFFER_SIZE)
5746 smtp_inend = smtp_inbuffer + IN_BUFFER_SIZE - 1;
5747 c = smtp_inend - smtp_inptr;
5748 if (c > 150) c = 150; /* limit logged amount */
5750 incomplete_transaction_log(US"sync failure");
5751 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP protocol synchronization error "
5752 "(next input sent too soon: pipelining was%s advertised): "
5753 "rejected \"%s\" %s next input=\"%s\"",
5754 pipelining_advertised? "" : " not",
5755 smtp_cmd_buffer, host_and_ident(TRUE),
5756 string_printing(smtp_inptr));
5757 smtp_notquit_exit(US"synchronization-error", US"554",
5758 US"SMTP synchronization error");
5759 done = 1; /* Pretend eof - drops connection */
5763 case TOO_MANY_NONMAIL_CMD:
5764 s = smtp_cmd_buffer;
5765 while (*s != 0 && !isspace(*s)) s++;
5766 incomplete_transaction_log(US"too many non-mail commands");
5767 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
5768 "nonmail commands (last was \"%.*s\")", host_and_ident(FALSE),
5769 (int)(s - smtp_cmd_buffer), smtp_cmd_buffer);
5770 smtp_notquit_exit(US"bad-commands", US"554", US"Too many nonmail commands");
5771 done = 1; /* Pretend eof - drops connection */
5774 #ifdef SUPPORT_PROXY
5775 case PROXY_FAIL_IGNORE_CMD:
5776 smtp_printf("503 Command refused, required Proxy negotiation failed\r\n", FALSE);
5781 if (unknown_command_count++ >= smtp_max_unknown_commands)
5783 log_write(L_smtp_syntax_error, LOG_MAIN,
5784 "SMTP syntax error in \"%s\" %s %s",
5785 string_printing(smtp_cmd_buffer), host_and_ident(TRUE),
5786 US"unrecognized command");
5787 incomplete_transaction_log(US"unrecognized command");
5788 smtp_notquit_exit(US"bad-commands", US"500",
5789 US"Too many unrecognized commands");
5791 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
5792 "unrecognized commands (last was \"%s\")", host_and_ident(FALSE),
5793 string_printing(smtp_cmd_buffer));
5796 done = synprot_error(L_smtp_syntax_error, 500, NULL,
5797 US"unrecognized command");
5801 /* This label is used by goto's inside loops that want to break out to
5802 the end of the command-processing loop. */
5805 last_was_rej_mail = was_rej_mail; /* Remember some last commands for */
5806 last_was_rcpt = was_rcpt; /* protocol error handling */
5810 return done - 2; /* Convert yield values */
5816 authres_smtpauth(gstring * g)
5818 if (!sender_host_authenticated)
5821 g = string_append(g, 2, US";\n\tauth=pass (", sender_host_auth_pubname);
5823 if (Ustrcmp(sender_host_auth_pubname, "tls") != 0)
5824 g = string_append(g, 2, US") smtp.auth=", authenticated_id);
5825 else if (authenticated_id)
5826 g = string_append(g, 2, US") x509.auth=", authenticated_id);
5828 g = string_catn(g, US") reason=x509.auth", 17);
5830 if (authenticated_sender)
5831 g = string_append(g, 2, US" smtp.mailfrom=", authenticated_sender);
5839 /* End of smtp_in.c */