1 /*************************************************
2 * Exim - an Internet mail transport agent *
3 *************************************************/
5 /* Copyright (c) University of Cambridge 1995 - 2018 */
6 /* See the file NOTICE for conditions of use and distribution. */
8 /* Functions for handling an incoming SMTP call. */
15 /* Initialize for TCP wrappers if so configured. It appears that the macro
16 HAVE_IPV6 is used in some versions of the tcpd.h header, so we unset it before
17 including that header, and restore its value afterwards. */
19 #ifdef USE_TCP_WRAPPERS
22 #define EXIM_HAVE_IPV6
28 #define HAVE_IPV6 TRUE
31 int allow_severity = LOG_INFO;
32 int deny_severity = LOG_NOTICE;
33 uschar *tcp_wrappers_name;
37 /* Size of buffer for reading SMTP commands. We used to use 512, as defined
38 by RFC 821. However, RFC 1869 specifies that this must be increased for SMTP
39 commands that accept arguments, and this in particular applies to AUTH, where
40 the data can be quite long. More recently this value was 2048 in Exim;
41 however, RFC 4954 (circa 2007) recommends 12288 bytes to handle AUTH. Clients
42 such as Thunderbird will send an AUTH with an initial-response for GSSAPI.
43 The maximum size of a Kerberos ticket under Windows 2003 is 12000 bytes, and
44 we need room to handle large base64-encoded AUTHs for GSSAPI.
47 #define SMTP_CMD_BUFFER_SIZE 16384
49 /* Size of buffer for reading SMTP incoming packets */
51 #define IN_BUFFER_SIZE 8192
53 /* Structure for SMTP command list */
60 short int is_mail_cmd;
63 /* Codes for identifying commands. We order them so that those that come first
64 are those for which synchronization is always required. Checking this can help
68 /* These commands are required to be synchronized, i.e. to be the last in a
69 block of commands when pipelining. */
71 HELO_CMD, EHLO_CMD, DATA_CMD, /* These are listed in the pipelining */
72 VRFY_CMD, EXPN_CMD, NOOP_CMD, /* RFC as requiring synchronization */
73 ETRN_CMD, /* This by analogy with TURN from the RFC */
74 STARTTLS_CMD, /* Required by the STARTTLS RFC */
75 TLS_AUTH_CMD, /* auto-command at start of SSL */
77 /* This is a dummy to identify the non-sync commands when pipelining */
79 NON_SYNC_CMD_PIPELINING,
81 /* These commands need not be synchronized when pipelining */
83 MAIL_CMD, RCPT_CMD, RSET_CMD,
85 /* This is a dummy to identify the non-sync commands when not pipelining */
87 NON_SYNC_CMD_NON_PIPELINING,
89 /* RFC3030 section 2: "After all MAIL and RCPT responses are collected and
90 processed the message is sent using a series of BDAT commands"
91 implies that BDAT should be synchronized. However, we see Google, at least,
92 sending MAIL,RCPT,BDAT-LAST in a single packet, clearly not waiting for
93 processing of the RCPT response(s). We shall do the same, and not require
94 synch for BDAT. Worse, as the chunk may (very likely will) follow the
95 command-header in the same packet we cannot do the usual "is there any
96 follow-on data after the command line" even for non-pipeline mode.
97 So we'll need an explicit check after reading the expected chunk amount
98 when non-pipe, before sending the ACK. */
102 /* I have been unable to find a statement about the use of pipelining
103 with AUTH, so to be on the safe side it is here, though I kind of feel
104 it should be up there with the synchronized commands. */
108 /* I'm not sure about these, but I don't think they matter. */
113 PROXY_FAIL_IGNORE_CMD,
116 /* These are specials that don't correspond to actual commands */
118 EOF_CMD, OTHER_CMD, BADARG_CMD, BADCHAR_CMD, BADSYN_CMD,
119 TOO_MANY_NONMAIL_CMD };
122 /* This is a convenience macro for adding the identity of an SMTP command
123 to the circular buffer that holds a list of the last n received. */
126 smtp_connection_had[smtp_ch_index++] = n; \
127 if (smtp_ch_index >= SMTP_HBUFF_SIZE) smtp_ch_index = 0
130 /*************************************************
131 * Local static variables *
132 *************************************************/
135 BOOL auth_advertised :1;
137 BOOL tls_advertised :1;
138 # ifdef EXPERIMENTAL_REQUIRETLS
139 BOOL requiretls_advertised :1;
142 BOOL dsn_advertised :1;
144 BOOL helo_required :1;
147 BOOL helo_accept_junk :1;
148 #ifdef EXPERIMENTAL_PIPE_CONNECT
149 BOOL pipe_connect_acceptable :1;
151 BOOL rcpt_smtp_response_same :1;
152 BOOL rcpt_in_progress :1;
153 BOOL smtp_exit_function_called :1;
155 BOOL smtputf8_advertised :1;
158 .helo_required = FALSE,
159 .helo_verify = FALSE,
160 .smtp_exit_function_called = FALSE,
163 static auth_instance *authenticated_by;
164 static int count_nonmail;
165 static int nonmail_command_count;
166 static int synprot_error_count;
167 static int unknown_command_count;
168 static int sync_cmd_limit;
169 static int smtp_write_error = 0;
171 static uschar *rcpt_smtp_response;
172 static uschar *smtp_data_buffer;
173 static uschar *smtp_cmd_data;
175 /* We need to know the position of RSET, HELO, EHLO, AUTH, and STARTTLS. Their
176 final fields of all except AUTH are forced TRUE at the start of a new message
177 setup, to allow one of each between messages that is not counted as a nonmail
178 command. (In fact, only one of HELO/EHLO is not counted.) Also, we have to
179 allow a new EHLO after starting up TLS.
181 AUTH is "falsely" labelled as a mail command initially, so that it doesn't get
182 counted. However, the flag is changed when AUTH is received, so that multiple
183 failing AUTHs will eventually hit the limit. After a successful AUTH, another
184 AUTH is already forbidden. After a TLS session is started, AUTH's flag is again
185 forced TRUE, to allow for the re-authentication that can happen at that point.
187 QUIT is also "falsely" labelled as a mail command so that it doesn't up the
188 count of non-mail commands and possibly provoke an error.
190 tls_auth is a pseudo-command, never expected in input. It is activated
191 on TLS startup and looks for a tls authenticator. */
193 static smtp_cmd_list cmd_list[] = {
194 /* name len cmd has_arg is_mail_cmd */
196 { "rset", sizeof("rset")-1, RSET_CMD, FALSE, FALSE }, /* First */
197 { "helo", sizeof("helo")-1, HELO_CMD, TRUE, FALSE },
198 { "ehlo", sizeof("ehlo")-1, EHLO_CMD, TRUE, FALSE },
199 { "auth", sizeof("auth")-1, AUTH_CMD, TRUE, TRUE },
201 { "starttls", sizeof("starttls")-1, STARTTLS_CMD, FALSE, FALSE },
202 { "tls_auth", 0, TLS_AUTH_CMD, FALSE, FALSE },
205 /* If you change anything above here, also fix the definitions below. */
207 { "mail from:", sizeof("mail from:")-1, MAIL_CMD, TRUE, TRUE },
208 { "rcpt to:", sizeof("rcpt to:")-1, RCPT_CMD, TRUE, TRUE },
209 { "data", sizeof("data")-1, DATA_CMD, FALSE, TRUE },
210 { "bdat", sizeof("bdat")-1, BDAT_CMD, TRUE, TRUE },
211 { "quit", sizeof("quit")-1, QUIT_CMD, FALSE, TRUE },
212 { "noop", sizeof("noop")-1, NOOP_CMD, TRUE, FALSE },
213 { "etrn", sizeof("etrn")-1, ETRN_CMD, TRUE, FALSE },
214 { "vrfy", sizeof("vrfy")-1, VRFY_CMD, TRUE, FALSE },
215 { "expn", sizeof("expn")-1, EXPN_CMD, TRUE, FALSE },
216 { "help", sizeof("help")-1, HELP_CMD, TRUE, FALSE }
219 static smtp_cmd_list *cmd_list_end =
220 cmd_list + sizeof(cmd_list)/sizeof(smtp_cmd_list);
222 #define CMD_LIST_RSET 0
223 #define CMD_LIST_HELO 1
224 #define CMD_LIST_EHLO 2
225 #define CMD_LIST_AUTH 3
226 #define CMD_LIST_STARTTLS 4
227 #define CMD_LIST_TLS_AUTH 5
229 /* This list of names is used for performing the smtp_no_mail logging action.
230 It must be kept in step with the SCH_xxx enumerations. */
232 static uschar *smtp_names[] =
234 US"NONE", US"AUTH", US"DATA", US"BDAT", US"EHLO", US"ETRN", US"EXPN",
235 US"HELO", US"HELP", US"MAIL", US"NOOP", US"QUIT", US"RCPT", US"RSET",
236 US"STARTTLS", US"VRFY" };
238 static uschar *protocols_local[] = {
239 US"local-smtp", /* HELO */
240 US"local-smtps", /* The rare case EHLO->STARTTLS->HELO */
241 US"local-esmtp", /* EHLO */
242 US"local-esmtps", /* EHLO->STARTTLS->EHLO */
243 US"local-esmtpa", /* EHLO->AUTH */
244 US"local-esmtpsa" /* EHLO->STARTTLS->EHLO->AUTH */
246 static uschar *protocols[] = {
248 US"smtps", /* The rare case EHLO->STARTTLS->HELO */
249 US"esmtp", /* EHLO */
250 US"esmtps", /* EHLO->STARTTLS->EHLO */
251 US"esmtpa", /* EHLO->AUTH */
252 US"esmtpsa" /* EHLO->STARTTLS->EHLO->AUTH */
257 #define pcrpted 1 /* added to pextend or pnormal */
258 #define pauthed 2 /* added to pextend */
260 /* Sanity check and validate optional args to MAIL FROM: envelope */
263 ENV_MAIL_OPT_SIZE, ENV_MAIL_OPT_BODY, ENV_MAIL_OPT_AUTH,
267 ENV_MAIL_OPT_RET, ENV_MAIL_OPT_ENVID,
271 #ifdef EXPERIMENTAL_REQUIRETLS
276 uschar * name; /* option requested during MAIL cmd */
277 int value; /* enum type */
278 BOOL need_value; /* TRUE requires value (name=value pair format)
279 FALSE is a singleton */
281 static env_mail_type_t env_mail_type_list[] = {
282 { US"SIZE", ENV_MAIL_OPT_SIZE, TRUE },
283 { US"BODY", ENV_MAIL_OPT_BODY, TRUE },
284 { US"AUTH", ENV_MAIL_OPT_AUTH, TRUE },
286 { US"PRDR", ENV_MAIL_OPT_PRDR, FALSE },
288 { US"RET", ENV_MAIL_OPT_RET, TRUE },
289 { US"ENVID", ENV_MAIL_OPT_ENVID, TRUE },
291 { US"SMTPUTF8",ENV_MAIL_OPT_UTF8, FALSE }, /* rfc6531 */
293 #ifdef EXPERIMENTAL_REQUIRETLS
294 /* https://tools.ietf.org/html/draft-ietf-uta-smtp-require-tls-03 */
295 { US"REQUIRETLS",ENV_MAIL_OPT_REQTLS, FALSE },
297 /* keep this the last entry */
298 { US"NULL", ENV_MAIL_OPT_NULL, FALSE },
301 /* When reading SMTP from a remote host, we have to use our own versions of the
302 C input-reading functions, in order to be able to flush the SMTP output only
303 when about to read more data from the socket. This is the only way to get
304 optimal performance when the client is using pipelining. Flushing for every
305 command causes a separate packet and reply packet each time; saving all the
306 responses up (when pipelining) combines them into one packet and one response.
308 For simplicity, these functions are used for *all* SMTP input, not only when
309 receiving over a socket. However, after setting up a secure socket (SSL), input
310 is read via the OpenSSL library, and another set of functions is used instead
313 These functions are set in the receive_getc etc. variables and called with the
314 same interface as the C functions. However, since there can only ever be
315 one incoming SMTP call, we just use a single buffer and flags. There is no need
316 to implement a complicated private FILE-like structure.*/
318 static uschar *smtp_inbuffer;
319 static uschar *smtp_inptr;
320 static uschar *smtp_inend;
321 static int smtp_had_eof;
322 static int smtp_had_error;
325 /* forward declarations */
326 static int smtp_read_command(BOOL check_sync, unsigned buffer_lim);
327 static int synprot_error(int type, int code, uschar *data, uschar *errmess);
328 static void smtp_quit_handler(uschar **, uschar **);
329 static void smtp_rset_handler(void);
331 /*************************************************
332 * Recheck synchronization *
333 *************************************************/
335 /* Synchronization checks can never be perfect because a packet may be on its
336 way but not arrived when the check is done. Normally, the checks happen when
337 commands are read: Exim ensures that there is no more input in the input buffer.
338 In normal cases, the response to the command will be fast, and there is no
341 However, for some commands an ACL is run, and that can include delays. In those
342 cases, it is useful to do another check on the input just before sending the
343 response. This also applies at the start of a connection. This function does
344 that check by means of the select() function, as long as the facility is not
345 disabled or inappropriate. A failure of select() is ignored.
347 When there is unwanted input, we read it so that it appears in the log of the
351 Returns: TRUE if all is well; FALSE if there is input pending
355 wouldblock_reading(void)
359 struct timeval tzero;
362 if (tls_in.active.sock >= 0)
363 return !tls_could_read();
366 if (smtp_inptr < smtp_inend)
369 fd = fileno(smtp_in);
374 rc = select(fd + 1, (SELECT_ARG2_TYPE *)&fds, NULL, NULL, &tzero);
376 if (rc <= 0) return TRUE; /* Not ready to read */
377 rc = smtp_getc(GETC_BUFFER_UNLIMITED);
378 if (rc < 0) return TRUE; /* End of file or error */
387 if (!smtp_enforce_sync || !sender_host_address || f.sender_host_notsocket)
390 return wouldblock_reading();
394 /* If there's input waiting (and we're doing pipelineing) then we can pipeline
395 a reponse with the one following. */
398 pipeline_response(void)
400 if ( !smtp_enforce_sync || !sender_host_address
401 || f.sender_host_notsocket || !f.smtp_in_pipelining_advertised)
404 if (wouldblock_reading()) return FALSE;
405 f.smtp_in_pipelining_used = TRUE;
410 #ifdef EXPERIMENTAL_PIPE_CONNECT
412 pipeline_connect_sends(void)
414 if (!sender_host_address || f.sender_host_notsocket || !fl.pipe_connect_acceptable)
417 if (wouldblock_reading()) return FALSE;
418 f.smtp_in_early_pipe_used = TRUE;
423 /*************************************************
424 * Log incomplete transactions *
425 *************************************************/
427 /* This function is called after a transaction has been aborted by RSET, QUIT,
428 connection drops or other errors. It logs the envelope information received
429 so far in order to preserve address verification attempts.
431 Argument: string to indicate what aborted the transaction
436 incomplete_transaction_log(uschar *what)
438 if (sender_address == NULL || /* No transaction in progress */
439 !LOGGING(smtp_incomplete_transaction))
442 /* Build list of recipients for logging */
444 if (recipients_count > 0)
447 raw_recipients = store_get(recipients_count * sizeof(uschar *));
448 for (i = 0; i < recipients_count; i++)
449 raw_recipients[i] = recipients_list[i].address;
450 raw_recipients_count = recipients_count;
453 log_write(L_smtp_incomplete_transaction, LOG_MAIN|LOG_SENDER|LOG_RECIPIENTS,
454 "%s incomplete transaction (%s)", host_and_ident(TRUE), what);
461 smtp_command_timeout_exit(void)
463 log_write(L_lost_incoming_connection,
464 LOG_MAIN, "SMTP command timeout on%s connection from %s",
465 tls_in.active.sock >= 0 ? " TLS" : "", host_and_ident(FALSE));
466 if (smtp_batched_input)
467 moan_smtp_batch(NULL, "421 SMTP command timeout"); /* Does not return */
468 smtp_notquit_exit(US"command-timeout", US"421",
469 US"%s: SMTP command timeout - closing connection",
470 smtp_active_hostname);
471 exim_exit(EXIT_FAILURE, US"receiving");
475 smtp_command_sigterm_exit(void)
477 log_write(0, LOG_MAIN, "%s closed after SIGTERM", smtp_get_connection_info());
478 if (smtp_batched_input)
479 moan_smtp_batch(NULL, "421 SIGTERM received"); /* Does not return */
480 smtp_notquit_exit(US"signal-exit", US"421",
481 US"%s: Service not available - closing connection", smtp_active_hostname);
482 exim_exit(EXIT_FAILURE, US"receiving");
486 smtp_data_timeout_exit(void)
488 log_write(L_lost_incoming_connection,
489 LOG_MAIN, "SMTP data timeout (message abandoned) on connection from %s F=<%s>",
490 sender_fullhost ? sender_fullhost : US"local process", sender_address);
491 receive_bomb_out(US"data-timeout", US"SMTP incoming data timeout");
492 /* Does not return */
496 smtp_data_sigint_exit(void)
498 log_write(0, LOG_MAIN, "%s closed after %s",
499 smtp_get_connection_info(), had_data_sigint == SIGTERM ? "SIGTERM":"SIGINT");
500 receive_bomb_out(US"signal-exit",
501 US"Service not available - SIGTERM or SIGINT received");
502 /* Does not return */
507 /* Refill the buffer, and notify DKIM verification code.
508 Return false for error or EOF.
512 smtp_refill(unsigned lim)
515 if (!smtp_out) return FALSE;
517 if (smtp_receive_timeout > 0) ALARM(smtp_receive_timeout);
519 /* Limit amount read, so non-message data is not fed to DKIM.
520 Take care to not touch the safety NUL at the end of the buffer. */
522 rc = read(fileno(smtp_in), smtp_inbuffer, MIN(IN_BUFFER_SIZE-1, lim));
524 if (smtp_receive_timeout > 0) ALARM_CLR(0);
527 /* Must put the error text in fixed store, because this might be during
528 header reading, where it releases unused store above the header. */
531 if (had_command_timeout) /* set by signal handler */
532 smtp_command_timeout_exit(); /* does not return */
533 if (had_command_sigterm)
534 smtp_command_sigterm_exit();
535 if (had_data_timeout)
536 smtp_data_timeout_exit();
538 smtp_data_sigint_exit();
540 smtp_had_error = save_errno;
541 smtp_read_error = string_copy_malloc(
542 string_sprintf(" (error: %s)", strerror(save_errno)));
549 dkim_exim_verify_feed(smtp_inbuffer, rc);
551 smtp_inend = smtp_inbuffer + rc;
552 smtp_inptr = smtp_inbuffer;
556 /*************************************************
557 * SMTP version of getc() *
558 *************************************************/
560 /* This gets the next byte from the SMTP input buffer. If the buffer is empty,
561 it flushes the output, and refills the buffer, with a timeout. The signal
562 handler is set appropriately by the calling function. This function is not used
563 after a connection has negotiated itself into an TLS/SSL state.
565 Arguments: lim Maximum amount to read/buffer
566 Returns: the next character or EOF
570 smtp_getc(unsigned lim)
572 if (smtp_inptr >= smtp_inend)
573 if (!smtp_refill(lim))
575 return *smtp_inptr++;
579 smtp_getbuf(unsigned * len)
584 if (smtp_inptr >= smtp_inend)
585 if (!smtp_refill(*len))
586 { *len = 0; return NULL; }
588 if ((size = smtp_inend - smtp_inptr) > *len) size = *len;
599 int n = smtp_inend - smtp_inptr;
601 dkim_exim_verify_feed(smtp_inptr, n);
606 /* Get a byte from the smtp input, in CHUNKING mode. Handle ack of the
607 previous BDAT chunk and getting new ones when we run out. Uses the
608 underlying smtp_getc or tls_getc both for that and for getting the
609 (buffered) data byte. EOD signals (an expected) no further data.
610 ERR signals a protocol error, and EOF a closed input stream.
612 Called from read_bdat_smtp() in receive.c for the message body, but also
613 by the headers read loop in receive_msg(); manipulates chunking_state
614 to handle the BDAT command/response.
615 Placed here due to the correlation with the above smtp_getc(), which it wraps,
616 and also by the need to do smtp command/response handling.
618 Arguments: lim (ignored)
619 Returns: the next character or ERR, EOD or EOF
623 bdat_getc(unsigned lim)
625 uschar * user_msg = NULL;
634 if (chunking_data_left > 0)
635 return lwr_receive_getc(chunking_data_left--);
637 receive_getc = lwr_receive_getc;
638 receive_getbuf = lwr_receive_getbuf;
639 receive_ungetc = lwr_receive_ungetc;
641 dkim_save = dkim_collect_input;
642 dkim_collect_input = 0;
645 /* Unless PIPELINING was offered, there should be no next command
646 until after we ack that chunk */
648 if (!f.smtp_in_pipelining_advertised && !check_sync())
650 unsigned n = smtp_inend - smtp_inptr;
653 incomplete_transaction_log(US"sync failure");
654 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP protocol synchronization error "
655 "(next input sent too soon: pipelining was not advertised): "
656 "rejected \"%s\" %s next input=\"%s\"%s",
657 smtp_cmd_buffer, host_and_ident(TRUE),
658 string_printing(string_copyn(smtp_inptr, n)),
659 smtp_inend - smtp_inptr > n ? "..." : "");
660 (void) synprot_error(L_smtp_protocol_error, 554, NULL,
661 US"SMTP synchronization error");
662 goto repeat_until_rset;
665 /* If not the last, ack the received chunk. The last response is delayed
666 until after the data ACL decides on it */
668 if (chunking_state == CHUNKING_LAST)
671 dkim_exim_verify_feed(NULL, 0); /* notify EOD */
676 smtp_printf("250 %u byte chunk received\r\n", FALSE, chunking_datasize);
677 chunking_state = CHUNKING_OFFERED;
678 DEBUG(D_receive) debug_printf("chunking state %d\n", (int)chunking_state);
680 /* Expect another BDAT cmd from input. RFC 3030 says nothing about
681 QUIT, RSET or NOOP but handling them seems obvious */
684 switch(smtp_read_command(TRUE, 1))
687 (void) synprot_error(L_smtp_protocol_error, 503, NULL,
688 US"only BDAT permissible after non-LAST BDAT");
691 switch(smtp_read_command(TRUE, 1))
693 case QUIT_CMD: smtp_quit_handler(&user_msg, &log_msg); /*FALLTHROUGH */
694 case EOF_CMD: return EOF;
695 case RSET_CMD: smtp_rset_handler(); return ERR;
696 default: if (synprot_error(L_smtp_protocol_error, 503, NULL,
697 US"only RSET accepted now") > 0)
699 goto repeat_until_rset;
703 smtp_quit_handler(&user_msg, &log_msg);
714 smtp_printf("250 OK\r\n", FALSE);
721 if (sscanf(CS smtp_cmd_data, "%u %n", &chunking_datasize, &n) < 1)
723 (void) synprot_error(L_smtp_protocol_error, 501, NULL,
724 US"missing size for BDAT command");
727 chunking_state = strcmpic(smtp_cmd_data+n, US"LAST") == 0
728 ? CHUNKING_LAST : CHUNKING_ACTIVE;
729 chunking_data_left = chunking_datasize;
730 DEBUG(D_receive) debug_printf("chunking state %d, %d bytes\n",
731 (int)chunking_state, chunking_data_left);
733 if (chunking_datasize == 0)
734 if (chunking_state == CHUNKING_LAST)
738 (void) synprot_error(L_smtp_protocol_error, 504, NULL,
739 US"zero size for BDAT command");
740 goto repeat_until_rset;
743 receive_getc = bdat_getc;
744 receive_getbuf = bdat_getbuf; /* r~getbuf is never actually used */
745 receive_ungetc = bdat_ungetc;
747 dkim_collect_input = dkim_save;
749 break; /* to top of main loop */
756 bdat_getbuf(unsigned * len)
760 if (chunking_data_left <= 0)
761 { *len = 0; return NULL; }
763 if (*len > chunking_data_left) *len = chunking_data_left;
764 buf = lwr_receive_getbuf(len); /* Either smtp_getbuf or tls_getbuf */
765 chunking_data_left -= *len;
770 bdat_flush_data(void)
772 while (chunking_data_left)
774 unsigned n = chunking_data_left;
775 if (!bdat_getbuf(&n)) break;
778 receive_getc = lwr_receive_getc;
779 receive_getbuf = lwr_receive_getbuf;
780 receive_ungetc = lwr_receive_ungetc;
782 if (chunking_state != CHUNKING_LAST)
784 chunking_state = CHUNKING_OFFERED;
785 DEBUG(D_receive) debug_printf("chunking state %d\n", (int)chunking_state);
792 /*************************************************
793 * SMTP version of ungetc() *
794 *************************************************/
796 /* Puts a character back in the input buffer. Only ever
802 Returns: the character
816 chunking_data_left++;
817 return lwr_receive_ungetc(ch);
822 /*************************************************
823 * SMTP version of feof() *
824 *************************************************/
826 /* Tests for a previous EOF
829 Returns: non-zero if the eof flag is set
841 /*************************************************
842 * SMTP version of ferror() *
843 *************************************************/
845 /* Tests for a previous read error, and returns with errno
846 restored to what it was when the error was detected.
849 Returns: non-zero if the error flag is set
855 errno = smtp_had_error;
856 return smtp_had_error;
861 /*************************************************
862 * Test for characters in the SMTP buffer *
863 *************************************************/
865 /* Used at the end of a message
874 return smtp_inptr < smtp_inend;
879 /*************************************************
880 * Write formatted string to SMTP channel *
881 *************************************************/
883 /* This is a separate function so that we don't have to repeat everything for
884 TLS support or debugging. It is global so that the daemon and the
885 authentication functions can use it. It does not return any error indication,
886 because major problems such as dropped connections won't show up till an output
887 flush for non-TLS connections. The smtp_fflush() function is available for
888 checking that: for convenience, TLS output errors are remembered here so that
889 they are also picked up later by smtp_fflush().
893 more further data expected
894 ... optional arguments
900 smtp_printf(const char *format, BOOL more, ...)
905 smtp_vprintf(format, more, ap);
909 /* This is split off so that verify.c:respond_printf() can, in effect, call
910 smtp_printf(), bearing in mind that in C a vararg function can't directly
911 call another vararg function, only a function which accepts a va_list. */
914 smtp_vprintf(const char *format, BOOL more, va_list ap)
916 gstring gs = { .size = big_buffer_size, .ptr = 0, .s = big_buffer };
919 yield = !! string_vformat(&gs, FALSE, format, ap);
920 string_from_gstring(&gs);
924 void *reset_point = store_get(0);
925 uschar *msg_copy, *cr, *end;
926 msg_copy = string_copy(gs.s);
927 end = msg_copy + gs.ptr;
928 while ((cr = Ustrchr(msg_copy, '\r')) != NULL) /* lose CRs */
929 memmove(cr, cr + 1, (end--) - cr);
930 debug_printf("SMTP>> %s", msg_copy);
931 store_reset(reset_point);
936 log_write(0, LOG_MAIN|LOG_PANIC, "string too large in smtp_printf()");
937 smtp_closedown(US"Unexpected error");
938 exim_exit(EXIT_FAILURE, NULL);
941 /* If this is the first output for a (non-batch) RCPT command, see if all RCPTs
942 have had the same. Note: this code is also present in smtp_respond(). It would
943 be tidier to have it only in one place, but when it was added, it was easier to
944 do it that way, so as not to have to mess with the code for the RCPT command,
945 which sometimes uses smtp_printf() and sometimes smtp_respond(). */
947 if (fl.rcpt_in_progress)
949 if (rcpt_smtp_response == NULL)
950 rcpt_smtp_response = string_copy(big_buffer);
951 else if (fl.rcpt_smtp_response_same &&
952 Ustrcmp(rcpt_smtp_response, big_buffer) != 0)
953 fl.rcpt_smtp_response_same = FALSE;
954 fl.rcpt_in_progress = FALSE;
957 /* Now write the string */
960 if (tls_in.active.sock >= 0)
962 if (tls_write(NULL, gs.s, gs.ptr, more) < 0)
963 smtp_write_error = -1;
968 if (fprintf(smtp_out, "%s", gs.s) < 0) smtp_write_error = -1;
973 /*************************************************
974 * Flush SMTP out and check for error *
975 *************************************************/
977 /* This function isn't currently used within Exim (it detects errors when it
978 tries to read the next SMTP input), but is available for use in local_scan().
979 For non-TLS connections, it flushes the output and checks for errors. For
980 TLS-connections, it checks for a previously-detected TLS write error.
983 Returns: 0 for no error; -1 after an error
989 if (tls_in.active.sock < 0 && fflush(smtp_out) != 0) smtp_write_error = -1;
990 return smtp_write_error;
995 /*************************************************
996 * SMTP command read timeout *
997 *************************************************/
999 /* Signal handler for timing out incoming SMTP commands. This attempts to
1002 Argument: signal number (SIGALRM)
1007 command_timeout_handler(int sig)
1009 had_command_timeout = sig;
1014 /*************************************************
1015 * SIGTERM received *
1016 *************************************************/
1018 /* Signal handler for handling SIGTERM. Again, try to finish tidily.
1020 Argument: signal number (SIGTERM)
1025 command_sigterm_handler(int sig)
1027 had_command_sigterm = sig;
1033 #ifdef SUPPORT_PROXY
1034 /*************************************************
1035 * Restore socket timeout to previous value *
1036 *************************************************/
1037 /* If the previous value was successfully retrieved, restore
1038 it before returning control to the non-proxy routines
1040 Arguments: fd - File descriptor for input
1041 get_ok - Successfully retrieved previous values
1042 tvtmp - Time struct with previous values
1043 vslen - Length of time struct
1047 restore_socket_timeout(int fd, int get_ok, struct timeval * tvtmp, socklen_t vslen)
1050 (void) setsockopt(fd, SOL_SOCKET, SO_RCVTIMEO, CS tvtmp, vslen);
1053 /*************************************************
1054 * Check if host is required proxy host *
1055 *************************************************/
1056 /* The function determines if inbound host will be a regular smtp host
1057 or if it is configured that it must use Proxy Protocol. A local
1065 check_proxy_protocol_host()
1069 if ( sender_host_address
1070 && (rc = verify_check_this_host(CUSS &hosts_proxy, NULL, NULL,
1071 sender_host_address, NULL)) == OK)
1074 debug_printf("Detected proxy protocol configured host\n");
1075 proxy_session = TRUE;
1077 return proxy_session;
1081 /*************************************************
1082 * Read data until newline or end of buffer *
1083 *************************************************/
1084 /* While SMTP is server-speaks-first, TLS is client-speaks-first, so we can't
1085 read an entire buffer and assume there will be nothing past a proxy protocol
1086 header. Our approach normally is to use stdio, but again that relies upon
1087 "STARTTLS\r\n" and a server response before the client starts TLS handshake, or
1088 reading _nothing_ before client TLS handshake. So we don't want to use the
1089 usual buffering reads which may read enough to block TLS starting.
1091 So unfortunately we're down to "read one byte at a time, with a syscall each,
1092 and expect a little overhead", for all proxy-opened connections which are v1,
1093 just to handle the TLS-on-connect case. Since SSL functions wrap the
1094 underlying fd, we can't assume that we can feed them any already-read content.
1096 We need to know where to read to, the max capacity, and we'll read until we
1097 get a CR and one more character. Let the caller scream if it's CR+!LF.
1099 Return the amount read.
1103 swallow_until_crlf(int fd, uschar *base, int already, int capacity)
1105 uschar *to = base + already;
1111 /* For "PROXY UNKNOWN\r\n" we, at time of writing, expect to have read
1112 up through the \r; for the _normal_ case, we haven't yet seen the \r. */
1114 cr = memchr(base, '\r', already);
1117 if ((cr - base) < already - 1)
1119 /* \r and presumed \n already within what we have; probably not
1120 actually proxy protocol, but abort cleanly. */
1123 /* \r is last character read, just need one more. */
1127 while (capacity > 0)
1129 do { ret = recv(fd, to, 1, 0); } while (ret == -1 && errno == EINTR);
1141 /* reached end without having room for a final newline, abort */
1146 /*************************************************
1147 * Setup host for proxy protocol *
1148 *************************************************/
1149 /* The function configures the connection based on a header from the
1150 inbound host to use Proxy Protocol. The specification is very exact
1151 so exit with an error if do not find the exact required pieces. This
1152 includes an incorrect number of spaces separating args.
1155 Returns: Boolean success
1159 setup_proxy_protocol_host()
1171 struct { /* TCP/UDP over IPv4, len = 12 */
1177 struct { /* TCP/UDP over IPv6, len = 36 */
1178 uint8_t src_addr[16];
1179 uint8_t dst_addr[16];
1183 struct { /* AF_UNIX sockets, len = 216 */
1184 uschar src_addr[108];
1185 uschar dst_addr[108];
1191 /* Temp variables used in PPv2 address:port parsing */
1193 char tmpip[INET_ADDRSTRLEN];
1194 struct sockaddr_in tmpaddr;
1195 char tmpip6[INET6_ADDRSTRLEN];
1196 struct sockaddr_in6 tmpaddr6;
1198 /* We can't read "all data until end" because while SMTP is
1199 server-speaks-first, the TLS handshake is client-speaks-first, so for
1200 TLS-on-connect ports the proxy protocol header will usually be immediately
1201 followed by a TLS handshake, and with N TLS libraries, we can't reliably
1202 reinject data for reading by those. So instead we first read "enough to be
1203 safely read within the header, and figure out how much more to read".
1204 For v1 we will later read to the end-of-line, for v2 we will read based upon
1207 The v2 sig is 12 octets, and another 4 gets us the length, so we know how much
1208 data is needed total. For v1, where the line looks like:
1209 PROXY TCPn L3src L3dest SrcPort DestPort \r\n
1211 However, for v1 there's also `PROXY UNKNOWN\r\n` which is only 15 octets.
1212 We seem to support that. So, if we read 14 octets then we can tell if we're
1213 v2 or v1. If we're v1, we can continue reading as normal.
1215 If we're v2, we can't slurp up the entire header. We need the length in the
1216 15th & 16th octets, then to read everything after that.
1218 So to safely handle v1 and v2, with client-sent-first supported correctly,
1219 we have to do a minimum of 3 read calls, not 1. Eww.
1222 #define PROXY_INITIAL_READ 14
1223 #define PROXY_V2_HEADER_SIZE 16
1224 #if PROXY_INITIAL_READ > PROXY_V2_HEADER_SIZE
1225 # error Code bug in sizes of data to read for proxy usage
1230 int fd = fileno(smtp_in);
1231 const char v2sig[12] = "\x0D\x0A\x0D\x0A\x00\x0D\x0A\x51\x55\x49\x54\x0A";
1232 uschar * iptype; /* To display debug info */
1234 struct timeval tvtmp;
1235 socklen_t vslen = sizeof(struct timeval);
1238 /* Save current socket timeout values */
1239 get_ok = getsockopt(fd, SOL_SOCKET, SO_RCVTIMEO, CS &tvtmp, &vslen);
1241 /* Proxy Protocol host must send header within a short time
1242 (default 3 seconds) or it's considered invalid */
1243 tv.tv_sec = PROXY_NEGOTIATION_TIMEOUT_SEC;
1244 tv.tv_usec = PROXY_NEGOTIATION_TIMEOUT_USEC;
1245 if (setsockopt(fd, SOL_SOCKET, SO_RCVTIMEO, CS &tv, sizeof(tv)) < 0)
1250 /* The inbound host was declared to be a Proxy Protocol host, so
1251 don't do a PEEK into the data, actually slurp up enough to be
1252 "safe". Can't take it all because TLS-on-connect clients follow
1253 immediately with TLS handshake. */
1254 ret = recv(fd, &hdr, PROXY_INITIAL_READ, 0);
1256 while (ret == -1 && errno == EINTR);
1261 /* For v2, handle reading the length, and then the rest. */
1262 if ((ret == PROXY_INITIAL_READ) && (memcmp(&hdr.v2, v2sig, sizeof(v2sig)) == 0))
1267 /* First get the length fields. */
1270 retmore = recv(fd, (uschar*)&hdr + ret, PROXY_V2_HEADER_SIZE - PROXY_INITIAL_READ, 0);
1271 } while (retmore == -1 && errno == EINTR);
1276 ver = (hdr.v2.ver_cmd & 0xf0) >> 4;
1278 /* May 2014: haproxy combined the version and command into one byte to
1279 allow two full bytes for the length field in order to proxy SSL
1280 connections. SSL Proxy is not supported in this version of Exim, but
1281 must still separate values here. */
1285 DEBUG(D_receive) debug_printf("Invalid Proxy Protocol version: %d\n", ver);
1289 /* The v2 header will always be 16 bytes per the spec. */
1290 size = 16 + ntohs(hdr.v2.len);
1291 DEBUG(D_receive) debug_printf("Detected PROXYv2 header, size %d (limit %d)\n",
1292 size, (int)sizeof(hdr));
1294 /* We should now have 16 octets (PROXY_V2_HEADER_SIZE), and we know the total
1295 amount that we need. Double-check that the size is not unreasonable, then
1297 if (size > sizeof(hdr))
1299 DEBUG(D_receive) debug_printf("PROXYv2 header size unreasonably large; security attack?\n");
1307 retmore = recv(fd, (uschar*)&hdr + ret, size-ret, 0);
1308 } while (retmore == -1 && errno == EINTR);
1312 DEBUG(D_receive) debug_printf("PROXYv2: have %d/%d required octets\n", ret, size);
1313 } while (ret < size);
1315 } /* end scope for getting rest of data for v2 */
1317 /* At this point: if PROXYv2, we've read the exact size required for all data;
1318 if PROXYv1 then we've read "less than required for any valid line" and should
1321 if (ret >= 16 && memcmp(&hdr.v2, v2sig, 12) == 0)
1323 uint8_t cmd = (hdr.v2.ver_cmd & 0x0f);
1327 case 0x01: /* PROXY command */
1330 case 0x11: /* TCPv4 address type */
1332 tmpaddr.sin_addr.s_addr = hdr.v2.addr.ip4.src_addr;
1333 inet_ntop(AF_INET, &tmpaddr.sin_addr, CS &tmpip, sizeof(tmpip));
1334 if (!string_is_ip_address(US tmpip, NULL))
1336 DEBUG(D_receive) debug_printf("Invalid %s source IP\n", iptype);
1339 proxy_local_address = sender_host_address;
1340 sender_host_address = string_copy(US tmpip);
1341 tmpport = ntohs(hdr.v2.addr.ip4.src_port);
1342 proxy_local_port = sender_host_port;
1343 sender_host_port = tmpport;
1344 /* Save dest ip/port */
1345 tmpaddr.sin_addr.s_addr = hdr.v2.addr.ip4.dst_addr;
1346 inet_ntop(AF_INET, &tmpaddr.sin_addr, CS &tmpip, sizeof(tmpip));
1347 if (!string_is_ip_address(US tmpip, NULL))
1349 DEBUG(D_receive) debug_printf("Invalid %s dest port\n", iptype);
1352 proxy_external_address = string_copy(US tmpip);
1353 tmpport = ntohs(hdr.v2.addr.ip4.dst_port);
1354 proxy_external_port = tmpport;
1356 case 0x21: /* TCPv6 address type */
1358 memmove(tmpaddr6.sin6_addr.s6_addr, hdr.v2.addr.ip6.src_addr, 16);
1359 inet_ntop(AF_INET6, &tmpaddr6.sin6_addr, CS &tmpip6, sizeof(tmpip6));
1360 if (!string_is_ip_address(US tmpip6, NULL))
1362 DEBUG(D_receive) debug_printf("Invalid %s source IP\n", iptype);
1365 proxy_local_address = sender_host_address;
1366 sender_host_address = string_copy(US tmpip6);
1367 tmpport = ntohs(hdr.v2.addr.ip6.src_port);
1368 proxy_local_port = sender_host_port;
1369 sender_host_port = tmpport;
1370 /* Save dest ip/port */
1371 memmove(tmpaddr6.sin6_addr.s6_addr, hdr.v2.addr.ip6.dst_addr, 16);
1372 inet_ntop(AF_INET6, &tmpaddr6.sin6_addr, CS &tmpip6, sizeof(tmpip6));
1373 if (!string_is_ip_address(US tmpip6, NULL))
1375 DEBUG(D_receive) debug_printf("Invalid %s dest port\n", iptype);
1378 proxy_external_address = string_copy(US tmpip6);
1379 tmpport = ntohs(hdr.v2.addr.ip6.dst_port);
1380 proxy_external_port = tmpport;
1384 debug_printf("Unsupported PROXYv2 connection type: 0x%02x\n",
1388 /* Unsupported protocol, keep local connection address */
1390 case 0x00: /* LOCAL command */
1391 /* Keep local connection address for LOCAL */
1396 debug_printf("Unsupported PROXYv2 command: 0x%x\n", cmd);
1400 else if (ret >= 8 && memcmp(hdr.v1.line, "PROXY", 5) == 0)
1404 uschar *sp; /* Utility variables follow */
1409 /* get the rest of the line */
1410 r2 = swallow_until_crlf(fd, (uschar*)&hdr, ret, sizeof(hdr)-ret);
1415 p = string_copy(hdr.v1.line);
1416 end = memchr(p, '\r', ret - 1);
1418 if (!end || (end == (uschar*)&hdr + ret) || end[1] != '\n')
1420 DEBUG(D_receive) debug_printf("Partial or invalid PROXY header\n");
1423 *end = '\0'; /* Terminate the string */
1424 size = end + 2 - p; /* Skip header + CRLF */
1425 DEBUG(D_receive) debug_printf("Detected PROXYv1 header\n");
1426 DEBUG(D_receive) debug_printf("Bytes read not within PROXY header: %d\n", ret - size);
1427 /* Step through the string looking for the required fields. Ensure
1428 strict adherence to required formatting, exit for any error. */
1430 if (!isspace(*(p++)))
1432 DEBUG(D_receive) debug_printf("Missing space after PROXY command\n");
1435 if (!Ustrncmp(p, CCS"TCP4", 4))
1437 else if (!Ustrncmp(p,CCS"TCP6", 4))
1439 else if (!Ustrncmp(p,CCS"UNKNOWN", 7))
1441 iptype = US"Unknown";
1446 DEBUG(D_receive) debug_printf("Invalid TCP type\n");
1450 p += Ustrlen(iptype);
1451 if (!isspace(*(p++)))
1453 DEBUG(D_receive) debug_printf("Missing space after TCP4/6 command\n");
1456 /* Find the end of the arg */
1457 if ((sp = Ustrchr(p, ' ')) == NULL)
1460 debug_printf("Did not find proxied src %s\n", iptype);
1464 if(!string_is_ip_address(p, NULL))
1467 debug_printf("Proxied src arg is not an %s address\n", iptype);
1470 proxy_local_address = sender_host_address;
1471 sender_host_address = p;
1473 if ((sp = Ustrchr(p, ' ')) == NULL)
1476 debug_printf("Did not find proxy dest %s\n", iptype);
1480 if(!string_is_ip_address(p, NULL))
1483 debug_printf("Proxy dest arg is not an %s address\n", iptype);
1486 proxy_external_address = p;
1488 if ((sp = Ustrchr(p, ' ')) == NULL)
1490 DEBUG(D_receive) debug_printf("Did not find proxied src port\n");
1494 tmp_port = strtol(CCS p, &endc, 10);
1495 if (*endc || tmp_port == 0)
1498 debug_printf("Proxied src port '%s' not an integer\n", p);
1501 proxy_local_port = sender_host_port;
1502 sender_host_port = tmp_port;
1504 if ((sp = Ustrchr(p, '\0')) == NULL)
1506 DEBUG(D_receive) debug_printf("Did not find proxy dest port\n");
1509 tmp_port = strtol(CCS p, &endc, 10);
1510 if (*endc || tmp_port == 0)
1513 debug_printf("Proxy dest port '%s' not an integer\n", p);
1516 proxy_external_port = tmp_port;
1517 /* Already checked for /r /n above. Good V1 header received. */
1521 /* Wrong protocol */
1522 DEBUG(D_receive) debug_printf("Invalid proxy protocol version negotiation\n");
1523 (void) swallow_until_crlf(fd, (uschar*)&hdr, ret, sizeof(hdr)-ret);
1529 debug_printf("Valid %s sender from Proxy Protocol header\n", iptype);
1530 yield = proxy_session;
1532 /* Don't flush any potential buffer contents. Any input on proxyfail
1533 should cause a synchronization failure */
1536 restore_socket_timeout(fd, get_ok, &tvtmp, vslen);
1541 sender_host_name = NULL;
1542 (void) host_name_lookup();
1543 host_build_sender_fullhost();
1547 f.proxy_session_failed = TRUE;
1549 debug_printf("Failure to extract proxied host, only QUIT allowed\n");
1556 /*************************************************
1557 * Read one command line *
1558 *************************************************/
1560 /* Strictly, SMTP commands coming over the net are supposed to end with CRLF.
1561 There are sites that don't do this, and in any case internal SMTP probably
1562 should check only for LF. Consequently, we check here for LF only. The line
1563 ends up with [CR]LF removed from its end. If we get an overlong line, treat as
1564 an unknown command. The command is read into the global smtp_cmd_buffer so that
1565 it is available via $smtp_command.
1567 The character reading routine sets up a timeout for each block actually read
1568 from the input (which may contain more than one command). We set up a special
1569 signal handler that closes down the session on a timeout. Control does not
1570 return when it runs.
1573 check_sync if TRUE, check synchronization rules if global option is TRUE
1574 buffer_lim maximum to buffer in lower layer
1576 Returns: a code identifying the command (enumerated above)
1580 smtp_read_command(BOOL check_sync, unsigned buffer_lim)
1585 BOOL hadnull = FALSE;
1587 had_command_timeout = 0;
1588 os_non_restarting_signal(SIGALRM, command_timeout_handler);
1590 while ((c = (receive_getc)(buffer_lim)) != '\n' && c != EOF)
1592 if (ptr >= SMTP_CMD_BUFFER_SIZE)
1594 os_non_restarting_signal(SIGALRM, sigalrm_handler);
1602 smtp_cmd_buffer[ptr++] = c;
1605 receive_linecount++; /* For BSMTP errors */
1606 os_non_restarting_signal(SIGALRM, sigalrm_handler);
1608 /* If hit end of file, return pseudo EOF command. Whether we have a
1609 part-line already read doesn't matter, since this is an error state. */
1611 if (c == EOF) return EOF_CMD;
1613 /* Remove any CR and white space at the end of the line, and terminate the
1616 while (ptr > 0 && isspace(smtp_cmd_buffer[ptr-1])) ptr--;
1617 smtp_cmd_buffer[ptr] = 0;
1619 DEBUG(D_receive) debug_printf("SMTP<< %s\n", smtp_cmd_buffer);
1621 /* NULLs are not allowed in SMTP commands */
1623 if (hadnull) return BADCHAR_CMD;
1625 /* Scan command list and return identity, having set the data pointer
1626 to the start of the actual data characters. Check for SMTP synchronization
1629 for (p = cmd_list; p < cmd_list_end; p++)
1631 #ifdef SUPPORT_PROXY
1632 /* Only allow QUIT command if Proxy Protocol parsing failed */
1633 if (proxy_session && f.proxy_session_failed && p->cmd != QUIT_CMD)
1637 && strncmpic(smtp_cmd_buffer, US p->name, p->len) == 0
1638 && ( smtp_cmd_buffer[p->len-1] == ':' /* "mail from:" or "rcpt to:" */
1639 || smtp_cmd_buffer[p->len] == 0
1640 || smtp_cmd_buffer[p->len] == ' '
1643 if (smtp_inptr < smtp_inend && /* Outstanding input */
1644 p->cmd < sync_cmd_limit && /* Command should sync */
1645 check_sync && /* Local flag set */
1646 smtp_enforce_sync && /* Global flag set */
1647 sender_host_address != NULL && /* Not local input */
1648 !f.sender_host_notsocket) /* Really is a socket */
1651 /* The variables $smtp_command and $smtp_command_argument point into the
1652 unmodified input buffer. A copy of the latter is taken for actual
1653 processing, so that it can be chopped up into separate parts if necessary,
1654 for example, when processing a MAIL command options such as SIZE that can
1655 follow the sender address. */
1657 smtp_cmd_argument = smtp_cmd_buffer + p->len;
1658 while (isspace(*smtp_cmd_argument)) smtp_cmd_argument++;
1659 Ustrcpy(smtp_data_buffer, smtp_cmd_argument);
1660 smtp_cmd_data = smtp_data_buffer;
1662 /* Count non-mail commands from those hosts that are controlled in this
1663 way. The default is all hosts. We don't waste effort checking the list
1664 until we get a non-mail command, but then cache the result to save checking
1665 again. If there's a DEFER while checking the host, assume it's in the list.
1667 Note that one instance of RSET, EHLO/HELO, and STARTTLS is allowed at the
1668 start of each incoming message by fiddling with the value in the table. */
1670 if (!p->is_mail_cmd)
1672 if (count_nonmail == TRUE_UNSET) count_nonmail =
1673 verify_check_host(&smtp_accept_max_nonmail_hosts) != FAIL;
1674 if (count_nonmail && ++nonmail_command_count > smtp_accept_max_nonmail)
1675 return TOO_MANY_NONMAIL_CMD;
1678 /* If there is data for a command that does not expect it, generate the
1681 return (p->has_arg || *smtp_cmd_data == 0)? p->cmd : BADARG_CMD;
1685 #ifdef SUPPORT_PROXY
1686 /* Only allow QUIT command if Proxy Protocol parsing failed */
1687 if (proxy_session && f.proxy_session_failed)
1688 return PROXY_FAIL_IGNORE_CMD;
1691 /* Enforce synchronization for unknown commands */
1693 if ( smtp_inptr < smtp_inend /* Outstanding input */
1694 && check_sync /* Local flag set */
1695 && smtp_enforce_sync /* Global flag set */
1696 && sender_host_address /* Not local input */
1697 && !f.sender_host_notsocket) /* Really is a socket */
1705 /*************************************************
1706 * Forced closedown of call *
1707 *************************************************/
1709 /* This function is called from log.c when Exim is dying because of a serious
1710 disaster, and also from some other places. If an incoming non-batched SMTP
1711 channel is open, it swallows the rest of the incoming message if in the DATA
1712 phase, sends the reply string, and gives an error to all subsequent commands
1713 except QUIT. The existence of an SMTP call is detected by the non-NULLness of
1717 message SMTP reply string to send, excluding the code
1723 smtp_closedown(uschar *message)
1725 if (!smtp_in || smtp_batched_input) return;
1726 receive_swallow_smtp();
1727 smtp_printf("421 %s\r\n", FALSE, message);
1729 for (;;) switch(smtp_read_command(FALSE, GETC_BUFFER_UNLIMITED))
1735 smtp_printf("221 %s closing connection\r\n", FALSE, smtp_active_hostname);
1740 smtp_printf("250 Reset OK\r\n", FALSE);
1744 smtp_printf("421 %s\r\n", FALSE, message);
1752 /*************************************************
1753 * Set up connection info for logging *
1754 *************************************************/
1756 /* This function is called when logging information about an SMTP connection.
1757 It sets up appropriate source information, depending on the type of connection.
1758 If sender_fullhost is NULL, we are at a very early stage of the connection;
1759 just use the IP address.
1762 Returns: a string describing the connection
1766 smtp_get_connection_info(void)
1768 const uschar * hostname = sender_fullhost
1769 ? sender_fullhost : sender_host_address;
1772 return string_sprintf("SMTP connection from %s", hostname);
1774 if (f.sender_host_unknown || f.sender_host_notsocket)
1775 return string_sprintf("SMTP connection from %s", sender_ident);
1778 return string_sprintf("SMTP connection from %s (via inetd)", hostname);
1780 if (LOGGING(incoming_interface) && interface_address)
1781 return string_sprintf("SMTP connection from %s I=[%s]:%d", hostname,
1782 interface_address, interface_port);
1784 return string_sprintf("SMTP connection from %s", hostname);
1790 /* Append TLS-related information to a log line
1793 g String under construction: allocated string to extend, or NULL
1795 Returns: Allocated string or NULL
1798 s_tlslog(gstring * g)
1800 if (LOGGING(tls_cipher) && tls_in.cipher)
1801 g = string_append(g, 2, US" X=", tls_in.cipher);
1802 if (LOGGING(tls_certificate_verified) && tls_in.cipher)
1803 g = string_append(g, 2, US" CV=", tls_in.certificate_verified? "yes":"no");
1804 if (LOGGING(tls_peerdn) && tls_in.peerdn)
1805 g = string_append(g, 3, US" DN=\"", string_printing(tls_in.peerdn), US"\"");
1806 if (LOGGING(tls_sni) && tls_in.sni)
1807 g = string_append(g, 3, US" SNI=\"", string_printing(tls_in.sni), US"\"");
1812 /*************************************************
1813 * Log lack of MAIL if so configured *
1814 *************************************************/
1816 /* This function is called when an SMTP session ends. If the log selector
1817 smtp_no_mail is set, write a log line giving some details of what has happened
1818 in the SMTP session.
1825 smtp_log_no_mail(void)
1831 if (smtp_mailcmd_count > 0 || !LOGGING(smtp_no_mail))
1834 if (sender_host_authenticated)
1836 g = string_append(g, 2, US" A=", sender_host_authenticated);
1837 if (authenticated_id) g = string_append(g, 2, US":", authenticated_id);
1844 sep = smtp_connection_had[SMTP_HBUFF_SIZE-1] != SCH_NONE ? US" C=..." : US" C=";
1846 for (i = smtp_ch_index; i < SMTP_HBUFF_SIZE; i++)
1847 if (smtp_connection_had[i] != SCH_NONE)
1849 g = string_append(g, 2, sep, smtp_names[smtp_connection_had[i]]);
1853 for (i = 0; i < smtp_ch_index; i++)
1855 g = string_append(g, 2, sep, smtp_names[smtp_connection_had[i]]);
1859 if (!(s = string_from_gstring(g))) s = US"";
1861 log_write(0, LOG_MAIN, "no MAIL in %sSMTP connection from %s D=%s%s",
1862 f.tcp_in_fastopen ? f.tcp_in_fastopen_data ? US"TFO* " : US"TFO " : US"",
1863 host_and_ident(FALSE), string_timesince(&smtp_connection_start), s);
1867 /* Return list of recent smtp commands */
1873 gstring * list = NULL;
1876 for (i = smtp_ch_index; i < SMTP_HBUFF_SIZE; i++)
1877 if (smtp_connection_had[i] != SCH_NONE)
1878 list = string_append_listele(list, ',', smtp_names[smtp_connection_had[i]]);
1880 for (i = 0; i < smtp_ch_index; i++)
1881 list = string_append_listele(list, ',', smtp_names[smtp_connection_had[i]]);
1883 s = string_from_gstring(list);
1884 return s ? s : US"";
1890 /*************************************************
1891 * Check HELO line and set sender_helo_name *
1892 *************************************************/
1894 /* Check the format of a HELO line. The data for HELO/EHLO is supposed to be
1895 the domain name of the sending host, or an ip literal in square brackets. The
1896 argument is placed in sender_helo_name, which is in malloc store, because it
1897 must persist over multiple incoming messages. If helo_accept_junk is set, this
1898 host is permitted to send any old junk (needed for some broken hosts).
1899 Otherwise, helo_allow_chars can be used for rogue characters in general
1900 (typically people want to let in underscores).
1903 s the data portion of the line (already past any white space)
1905 Returns: TRUE or FALSE
1909 check_helo(uschar *s)
1912 uschar *end = s + Ustrlen(s);
1913 BOOL yield = fl.helo_accept_junk;
1915 /* Discard any previous helo name */
1917 if (sender_helo_name)
1919 store_free(sender_helo_name);
1920 sender_helo_name = NULL;
1923 /* Skip tests if junk is permitted. */
1927 /* Allow the new standard form for IPv6 address literals, namely,
1928 [IPv6:....], and because someone is bound to use it, allow an equivalent
1929 IPv4 form. Allow plain addresses as well. */
1936 if (strncmpic(s, US"[IPv6:", 6) == 0)
1937 yield = (string_is_ip_address(s+6, NULL) == 6);
1938 else if (strncmpic(s, US"[IPv4:", 6) == 0)
1939 yield = (string_is_ip_address(s+6, NULL) == 4);
1941 yield = (string_is_ip_address(s+1, NULL) != 0);
1946 /* Non-literals must be alpha, dot, hyphen, plus any non-valid chars
1947 that have been configured (usually underscore - sigh). */
1950 for (yield = TRUE; *s; s++)
1951 if (!isalnum(*s) && *s != '.' && *s != '-' &&
1952 Ustrchr(helo_allow_chars, *s) == NULL)
1958 /* Save argument if OK */
1960 if (yield) sender_helo_name = string_copy_malloc(start);
1968 /*************************************************
1969 * Extract SMTP command option *
1970 *************************************************/
1972 /* This function picks the next option setting off the end of smtp_cmd_data. It
1973 is called for MAIL FROM and RCPT TO commands, to pick off the optional ESMTP
1974 things that can appear there.
1977 name point this at the name
1978 value point this at the data string
1980 Returns: TRUE if found an option
1984 extract_option(uschar **name, uschar **value)
1987 uschar *v = smtp_cmd_data + Ustrlen(smtp_cmd_data) - 1;
1988 while (isspace(*v)) v--;
1990 while (v > smtp_cmd_data && *v != '=' && !isspace(*v))
1992 /* Take care to not stop at a space embedded in a quoted local-part */
1994 if (*v == '"') do v--; while (*v != '"' && v > smtp_cmd_data+1);
2001 while(isalpha(n[-1])) n--;
2002 /* RFC says SP, but TAB seen in wild and other major MTAs accept it */
2003 if (!isspace(n[-1])) return FALSE;
2009 if (v == smtp_cmd_data) return FALSE;
2021 /*************************************************
2022 * Reset for new message *
2023 *************************************************/
2025 /* This function is called whenever the SMTP session is reset from
2026 within either of the setup functions; also from the daemon loop.
2028 Argument: the stacking pool storage reset point
2033 smtp_reset(void *reset_point)
2035 recipients_list = NULL;
2036 rcpt_count = rcpt_defer_count = rcpt_fail_count =
2037 raw_recipients_count = recipients_count = recipients_list_max = 0;
2038 message_linecount = 0;
2040 acl_added_headers = NULL;
2041 acl_removed_headers = NULL;
2042 f.queue_only_policy = FALSE;
2043 rcpt_smtp_response = NULL;
2044 fl.rcpt_smtp_response_same = TRUE;
2045 fl.rcpt_in_progress = FALSE;
2046 f.deliver_freeze = FALSE; /* Can be set by ACL */
2047 freeze_tell = freeze_tell_config; /* Can be set by ACL */
2048 fake_response = OK; /* Can be set by ACL */
2049 #ifdef WITH_CONTENT_SCAN
2050 f.no_mbox_unspool = FALSE; /* Can be set by ACL */
2052 f.submission_mode = FALSE; /* Can be set by ACL */
2053 f.suppress_local_fixups = f.suppress_local_fixups_default; /* Can be set by ACL */
2054 f.active_local_from_check = local_from_check; /* Can be set by ACL */
2055 f.active_local_sender_retain = local_sender_retain; /* Can be set by ACL */
2056 sending_ip_address = NULL;
2057 return_path = sender_address = NULL;
2058 sender_data = NULL; /* Can be set by ACL */
2059 deliver_localpart_parent = deliver_localpart_orig = NULL;
2060 deliver_domain_parent = deliver_domain_orig = NULL;
2061 callout_address = NULL;
2062 submission_name = NULL; /* Can be set by ACL */
2063 raw_sender = NULL; /* After SMTP rewrite, before qualifying */
2064 sender_address_unrewritten = NULL; /* Set only after verify rewrite */
2065 sender_verified_list = NULL; /* No senders verified */
2066 memset(sender_address_cache, 0, sizeof(sender_address_cache));
2067 memset(sender_domain_cache, 0, sizeof(sender_domain_cache));
2069 authenticated_sender = NULL;
2070 #ifdef EXPERIMENTAL_BRIGHTMAIL
2072 bmi_verdicts = NULL;
2074 dnslist_domain = dnslist_matched = NULL;
2076 spf_header_comment = spf_received = spf_result = spf_smtp_comment = NULL;
2077 spf_result_guessed = FALSE;
2079 #ifndef DISABLE_DKIM
2080 dkim_cur_signer = dkim_signers =
2081 dkim_signing_domain = dkim_signing_selector = dkim_signatures = NULL;
2082 dkim_cur_signer = dkim_signers = dkim_signing_domain = dkim_signing_selector = NULL;
2083 f.dkim_disable_verify = FALSE;
2084 dkim_collect_input = 0;
2085 dkim_verify_overall = dkim_verify_status = dkim_verify_reason = NULL;
2086 dkim_key_length = 0;
2088 #ifdef EXPERIMENTAL_DMARC
2089 f.dmarc_has_been_checked = f.dmarc_disable_verify = f.dmarc_enable_forensic = FALSE;
2090 dmarc_domain_policy = dmarc_status = dmarc_status_text =
2091 dmarc_used_domain = NULL;
2093 #ifdef EXPERIMENTAL_ARC
2094 arc_state = arc_state_reason = NULL;
2098 deliver_host = deliver_host_address = NULL; /* Can be set by ACL */
2099 #ifndef DISABLE_PRDR
2100 prdr_requested = FALSE;
2103 message_smtputf8 = FALSE;
2105 body_linecount = body_zerocount = 0;
2107 sender_rate = sender_rate_limit = sender_rate_period = NULL;
2108 ratelimiters_mail = NULL; /* Updated by ratelimit ACL condition */
2109 /* Note that ratelimiters_conn persists across resets. */
2111 /* Reset message ACL variables */
2115 /* The message body variables use malloc store. They may be set if this is
2116 not the first message in an SMTP session and the previous message caused them
2117 to be referenced in an ACL. */
2121 store_free(message_body);
2122 message_body = NULL;
2125 if (message_body_end)
2127 store_free(message_body_end);
2128 message_body_end = NULL;
2131 /* Warning log messages are also saved in malloc store. They are saved to avoid
2132 repetition in the same message, but it seems right to repeat them for different
2135 while (acl_warn_logged)
2137 string_item *this = acl_warn_logged;
2138 acl_warn_logged = acl_warn_logged->next;
2141 store_reset(reset_point);
2148 /*************************************************
2149 * Initialize for incoming batched SMTP message *
2150 *************************************************/
2152 /* This function is called from smtp_setup_msg() in the case when
2153 smtp_batched_input is true. This happens when -bS is used to pass a whole batch
2154 of messages in one file with SMTP commands between them. All errors must be
2155 reported by sending a message, and only MAIL FROM, RCPT TO, and DATA are
2156 relevant. After an error on a sender, or an invalid recipient, the remainder
2157 of the message is skipped. The value of received_protocol is already set.
2160 Returns: > 0 message successfully started (reached DATA)
2161 = 0 QUIT read or end of file reached
2162 < 0 should not occur
2166 smtp_setup_batch_msg(void)
2169 void *reset_point = store_get(0);
2171 /* Save the line count at the start of each transaction - single commands
2172 like HELO and RSET count as whole transactions. */
2174 bsmtp_transaction_linecount = receive_linecount;
2176 if ((receive_feof)()) return 0; /* Treat EOF as QUIT */
2178 cancel_cutthrough_connection(TRUE, US"smtp_setup_batch_msg");
2179 smtp_reset(reset_point); /* Reset for start of message */
2181 /* Deal with SMTP commands. This loop is exited by setting done to a POSITIVE
2182 value. The values are 2 larger than the required yield of the function. */
2187 uschar *recipient = NULL;
2188 int start, end, sender_domain, recipient_domain;
2190 switch(smtp_read_command(FALSE, GETC_BUFFER_UNLIMITED))
2192 /* The HELO/EHLO commands set sender_address_helo if they have
2193 valid data; otherwise they are ignored, except that they do
2194 a reset of the state. */
2199 check_helo(smtp_cmd_data);
2203 cancel_cutthrough_connection(TRUE, US"RSET received");
2204 smtp_reset(reset_point);
2205 bsmtp_transaction_linecount = receive_linecount;
2209 /* The MAIL FROM command requires an address as an operand. All we
2210 do here is to parse it for syntactic correctness. The form "<>" is
2211 a special case which converts into an empty string. The start/end
2212 pointers in the original are not used further for this address, as
2213 it is the canonical extracted address which is all that is kept. */
2216 smtp_mailcmd_count++; /* Count for no-mail log */
2217 if (sender_address != NULL)
2218 /* The function moan_smtp_batch() does not return. */
2219 moan_smtp_batch(smtp_cmd_buffer, "503 Sender already given");
2221 if (smtp_cmd_data[0] == 0)
2222 /* The function moan_smtp_batch() does not return. */
2223 moan_smtp_batch(smtp_cmd_buffer, "501 MAIL FROM must have an address operand");
2225 /* Reset to start of message */
2227 cancel_cutthrough_connection(TRUE, US"MAIL received");
2228 smtp_reset(reset_point);
2230 /* Apply SMTP rewrite */
2232 raw_sender = ((rewrite_existflags & rewrite_smtp) != 0)?
2233 rewrite_one(smtp_cmd_data, rewrite_smtp|rewrite_smtp_sender, NULL, FALSE,
2234 US"", global_rewrite_rules) : smtp_cmd_data;
2236 /* Extract the address; the TRUE flag allows <> as valid */
2239 parse_extract_address(raw_sender, &errmess, &start, &end, &sender_domain,
2243 /* The function moan_smtp_batch() does not return. */
2244 moan_smtp_batch(smtp_cmd_buffer, "501 %s", errmess);
2246 sender_address = string_copy(raw_sender);
2248 /* Qualify unqualified sender addresses if permitted to do so. */
2251 && sender_address[0] != 0 && sender_address[0] != '@')
2252 if (f.allow_unqualified_sender)
2254 sender_address = rewrite_address_qualify(sender_address, FALSE);
2255 DEBUG(D_receive) debug_printf("unqualified address %s accepted "
2256 "and rewritten\n", raw_sender);
2258 /* The function moan_smtp_batch() does not return. */
2260 moan_smtp_batch(smtp_cmd_buffer, "501 sender address must contain "
2265 /* The RCPT TO command requires an address as an operand. All we do
2266 here is to parse it for syntactic correctness. There may be any number
2267 of RCPT TO commands, specifying multiple senders. We build them all into
2268 a data structure that is in argc/argv format. The start/end values
2269 given by parse_extract_address are not used, as we keep only the
2270 extracted address. */
2273 if (!sender_address)
2274 /* The function moan_smtp_batch() does not return. */
2275 moan_smtp_batch(smtp_cmd_buffer, "503 No sender yet given");
2277 if (smtp_cmd_data[0] == 0)
2278 /* The function moan_smtp_batch() does not return. */
2279 moan_smtp_batch(smtp_cmd_buffer,
2280 "501 RCPT TO must have an address operand");
2282 /* Check maximum number allowed */
2284 if (recipients_max > 0 && recipients_count + 1 > recipients_max)
2285 /* The function moan_smtp_batch() does not return. */
2286 moan_smtp_batch(smtp_cmd_buffer, "%s too many recipients",
2287 recipients_max_reject? "552": "452");
2289 /* Apply SMTP rewrite, then extract address. Don't allow "<>" as a
2290 recipient address */
2292 recipient = rewrite_existflags & rewrite_smtp
2293 ? rewrite_one(smtp_cmd_data, rewrite_smtp, NULL, FALSE, US"",
2294 global_rewrite_rules)
2297 recipient = parse_extract_address(recipient, &errmess, &start, &end,
2298 &recipient_domain, FALSE);
2301 /* The function moan_smtp_batch() does not return. */
2302 moan_smtp_batch(smtp_cmd_buffer, "501 %s", errmess);
2304 /* If the recipient address is unqualified, qualify it if permitted. Then
2305 add it to the list of recipients. */
2307 if (!recipient_domain)
2308 if (f.allow_unqualified_recipient)
2310 DEBUG(D_receive) debug_printf("unqualified address %s accepted\n",
2312 recipient = rewrite_address_qualify(recipient, TRUE);
2314 /* The function moan_smtp_batch() does not return. */
2316 moan_smtp_batch(smtp_cmd_buffer,
2317 "501 recipient address must contain a domain");
2319 receive_add_recipient(recipient, -1);
2323 /* The DATA command is legal only if it follows successful MAIL FROM
2324 and RCPT TO commands. This function is complete when a valid DATA
2325 command is encountered. */
2328 if (!sender_address || recipients_count <= 0)
2329 /* The function moan_smtp_batch() does not return. */
2330 if (!sender_address)
2331 moan_smtp_batch(smtp_cmd_buffer,
2332 "503 MAIL FROM:<sender> command must precede DATA");
2334 moan_smtp_batch(smtp_cmd_buffer,
2335 "503 RCPT TO:<recipient> must precede DATA");
2338 done = 3; /* DATA successfully achieved */
2339 message_ended = END_NOTENDED; /* Indicate in middle of message */
2344 /* The VRFY, EXPN, HELP, ETRN, and NOOP commands are ignored. */
2351 bsmtp_transaction_linecount = receive_linecount;
2362 /* The function moan_smtp_batch() does not return. */
2363 moan_smtp_batch(smtp_cmd_buffer, "501 Unexpected argument data");
2368 /* The function moan_smtp_batch() does not return. */
2369 moan_smtp_batch(smtp_cmd_buffer, "501 Unexpected NULL in SMTP command");
2374 /* The function moan_smtp_batch() does not return. */
2375 moan_smtp_batch(smtp_cmd_buffer, "500 Command unrecognized");
2380 return done - 2; /* Convert yield values */
2388 smtp_log_tls_fail(uschar * errstr)
2390 uschar * conn_info = smtp_get_connection_info();
2392 if (Ustrncmp(conn_info, US"SMTP ", 5) == 0) conn_info += 5;
2393 /* I'd like to get separated H= here, but too hard for now */
2395 log_write(0, LOG_MAIN, "TLS error on %s %s", conn_info, errstr);
2408 struct tcp_info tinfo;
2409 socklen_t len = sizeof(tinfo);
2411 if (getsockopt(fileno(smtp_out), IPPROTO_TCP, TCP_INFO, &tinfo, &len) == 0)
2412 #ifdef TCPI_OPT_SYN_DATA /* FreeBSD 11 does not seem to have this yet */
2413 if (tinfo.tcpi_options & TCPI_OPT_SYN_DATA)
2415 DEBUG(D_receive) debug_printf("TCP_FASTOPEN mode connection (ACKd data-on-SYN)\n");
2416 f.tcp_in_fastopen_data = f.tcp_in_fastopen = TRUE;
2420 if (tinfo.tcpi_state == TCP_SYN_RECV)
2422 DEBUG(D_receive) debug_printf("TCP_FASTOPEN mode connection (state TCP_SYN_RECV)\n");
2423 f.tcp_in_fastopen = TRUE;
2430 /*************************************************
2431 * Start an SMTP session *
2432 *************************************************/
2434 /* This function is called at the start of an SMTP session. Thereafter,
2435 smtp_setup_msg() is called to initiate each separate message. This
2436 function does host-specific testing, and outputs the banner line.
2439 Returns: FALSE if the session can not continue; something has
2440 gone wrong, or the connection to the host is blocked
2444 smtp_start_session(void)
2447 uschar *user_msg, *log_msg;
2452 gettimeofday(&smtp_connection_start, NULL);
2453 for (smtp_ch_index = 0; smtp_ch_index < SMTP_HBUFF_SIZE; smtp_ch_index++)
2454 smtp_connection_had[smtp_ch_index] = SCH_NONE;
2457 /* Default values for certain variables */
2459 fl.helo_seen = fl.esmtp = fl.helo_accept_junk = FALSE;
2460 smtp_mailcmd_count = 0;
2461 count_nonmail = TRUE_UNSET;
2462 synprot_error_count = unknown_command_count = nonmail_command_count = 0;
2463 smtp_delay_mail = smtp_rlm_base;
2464 fl.auth_advertised = FALSE;
2465 f.smtp_in_pipelining_advertised = f.smtp_in_pipelining_used = FALSE;
2466 f.pipelining_enable = TRUE;
2467 sync_cmd_limit = NON_SYNC_CMD_NON_PIPELINING;
2468 fl.smtp_exit_function_called = FALSE; /* For avoiding loop in not-quit exit */
2470 /* If receiving by -bs from a trusted user, or testing with -bh, we allow
2471 authentication settings from -oMaa to remain in force. */
2473 if (!host_checking && !f.sender_host_notsocket)
2474 sender_host_auth_pubname = sender_host_authenticated = NULL;
2475 authenticated_by = NULL;
2478 tls_in.cipher = tls_in.peerdn = NULL;
2479 tls_in.ourcert = tls_in.peercert = NULL;
2481 tls_in.ocsp = OCSP_NOT_REQ;
2482 fl.tls_advertised = FALSE;
2483 # ifdef EXPERIMENTAL_REQUIRETLS
2484 fl.requiretls_advertised = FALSE;
2487 fl.dsn_advertised = FALSE;
2489 fl.smtputf8_advertised = FALSE;
2492 /* Reset ACL connection variables */
2496 /* Allow for trailing 0 in the command and data buffers. */
2498 if (!(smtp_cmd_buffer = US malloc(2*SMTP_CMD_BUFFER_SIZE + 2)))
2499 log_write(0, LOG_MAIN|LOG_PANIC_DIE,
2500 "malloc() failed for SMTP command buffer");
2502 smtp_cmd_buffer[0] = 0;
2503 smtp_data_buffer = smtp_cmd_buffer + SMTP_CMD_BUFFER_SIZE + 1;
2505 /* For batched input, the protocol setting can be overridden from the
2506 command line by a trusted caller. */
2508 if (smtp_batched_input)
2510 if (!received_protocol) received_protocol = US"local-bsmtp";
2513 /* For non-batched SMTP input, the protocol setting is forced here. It will be
2514 reset later if any of EHLO/AUTH/STARTTLS are received. */
2518 (sender_host_address ? protocols : protocols_local) [pnormal];
2520 /* Set up the buffer for inputting using direct read() calls, and arrange to
2521 call the local functions instead of the standard C ones. Place a NUL at the
2522 end of the buffer to safety-stop C-string reads from it. */
2524 if (!(smtp_inbuffer = US malloc(IN_BUFFER_SIZE)))
2525 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "malloc() failed for SMTP input buffer");
2526 smtp_inbuffer[IN_BUFFER_SIZE-1] = '\0';
2528 receive_getc = smtp_getc;
2529 receive_getbuf = smtp_getbuf;
2530 receive_get_cache = smtp_get_cache;
2531 receive_ungetc = smtp_ungetc;
2532 receive_feof = smtp_feof;
2533 receive_ferror = smtp_ferror;
2534 receive_smtp_buffered = smtp_buffered;
2535 smtp_inptr = smtp_inend = smtp_inbuffer;
2536 smtp_had_eof = smtp_had_error = 0;
2538 /* Set up the message size limit; this may be host-specific */
2540 thismessage_size_limit = expand_string_integer(message_size_limit, TRUE);
2541 if (expand_string_message)
2543 if (thismessage_size_limit == -1)
2544 log_write(0, LOG_MAIN|LOG_PANIC, "unable to expand message_size_limit: "
2545 "%s", expand_string_message);
2547 log_write(0, LOG_MAIN|LOG_PANIC, "invalid message_size_limit: "
2548 "%s", expand_string_message);
2549 smtp_closedown(US"Temporary local problem - please try later");
2553 /* When a message is input locally via the -bs or -bS options, sender_host_
2554 unknown is set unless -oMa was used to force an IP address, in which case it
2555 is checked like a real remote connection. When -bs is used from inetd, this
2556 flag is not set, causing the sending host to be checked. The code that deals
2557 with IP source routing (if configured) is never required for -bs or -bS and
2558 the flag sender_host_notsocket is used to suppress it.
2560 If smtp_accept_max and smtp_accept_reserve are set, keep some connections in
2561 reserve for certain hosts and/or networks. */
2563 if (!f.sender_host_unknown)
2566 BOOL reserved_host = FALSE;
2568 /* Look up IP options (source routing info) on the socket if this is not an
2569 -oMa "host", and if any are found, log them and drop the connection.
2571 Linux (and others now, see below) is different to everyone else, so there
2572 has to be some conditional compilation here. Versions of Linux before 2.1.15
2573 used a structure whose name was "options". Somebody finally realized that
2574 this name was silly, and it got changed to "ip_options". I use the
2575 newer name here, but there is a fudge in the script that sets up os.h
2576 to define a macro in older Linux systems.
2578 Sigh. Linux is a fast-moving target. Another generation of Linux uses
2579 glibc 2, which has chosen ip_opts for the structure name. This is now
2580 really a glibc thing rather than a Linux thing, so the condition name
2581 has been changed to reflect this. It is relevant also to GNU/Hurd.
2583 Mac OS 10.x (Darwin) is like the later glibc versions, but without the
2584 setting of the __GLIBC__ macro, so we can't detect it automatically. There's
2585 a special macro defined in the os.h file.
2587 Some DGUX versions on older hardware appear not to support IP options at
2588 all, so there is now a general macro which can be set to cut out this
2591 How to do this properly in IPv6 is not yet known. */
2593 #if !HAVE_IPV6 && !defined(NO_IP_OPTIONS)
2595 #ifdef GLIBC_IP_OPTIONS
2596 #if (!defined __GLIBC__) || (__GLIBC__ < 2)
2601 #elif defined DARWIN_IP_OPTIONS
2607 if (!host_checking && !f.sender_host_notsocket)
2610 EXIM_SOCKLEN_T optlen = sizeof(struct ip_options) + MAX_IPOPTLEN;
2611 struct ip_options *ipopt = store_get(optlen);
2613 struct ip_opts ipoptblock;
2614 struct ip_opts *ipopt = &ipoptblock;
2615 EXIM_SOCKLEN_T optlen = sizeof(ipoptblock);
2617 struct ipoption ipoptblock;
2618 struct ipoption *ipopt = &ipoptblock;
2619 EXIM_SOCKLEN_T optlen = sizeof(ipoptblock);
2622 /* Occasional genuine failures of getsockopt() have been seen - for
2623 example, "reset by peer". Therefore, just log and give up on this
2624 call, unless the error is ENOPROTOOPT. This error is given by systems
2625 that have the interfaces but not the mechanism - e.g. GNU/Hurd at the time
2626 of writing. So for that error, carry on - we just can't do an IP options
2629 DEBUG(D_receive) debug_printf("checking for IP options\n");
2631 if (getsockopt(fileno(smtp_out), IPPROTO_IP, IP_OPTIONS, US (ipopt),
2634 if (errno != ENOPROTOOPT)
2636 log_write(0, LOG_MAIN, "getsockopt() failed from %s: %s",
2637 host_and_ident(FALSE), strerror(errno));
2638 smtp_printf("451 SMTP service not available\r\n", FALSE);
2643 /* Deal with any IP options that are set. On the systems I have looked at,
2644 the value of MAX_IPOPTLEN has been 40, meaning that there should never be
2645 more logging data than will fit in big_buffer. Nevertheless, after somebody
2646 questioned this code, I've added in some paranoid checking. */
2648 else if (optlen > 0)
2650 uschar *p = big_buffer;
2651 uschar *pend = big_buffer + big_buffer_size;
2652 uschar *opt, *adptr;
2654 struct in_addr addr;
2657 uschar *optstart = US (ipopt->__data);
2659 uschar *optstart = US (ipopt->ip_opts);
2661 uschar *optstart = US (ipopt->ipopt_list);
2664 DEBUG(D_receive) debug_printf("IP options exist\n");
2666 Ustrcpy(p, "IP options on incoming call:");
2669 for (opt = optstart; opt != NULL &&
2670 opt < US (ipopt) + optlen;)
2684 if (!string_format(p, pend-p, " %s [@%s",
2685 (*opt == IPOPT_SSRR)? "SSRR" : "LSRR",
2687 inet_ntoa(*((struct in_addr *)(&(ipopt->faddr))))))
2689 inet_ntoa(ipopt->ip_dst)))
2691 inet_ntoa(ipopt->ipopt_dst)))
2699 optcount = (opt[1] - 3) / sizeof(struct in_addr);
2701 while (optcount-- > 0)
2703 memcpy(&addr, adptr, sizeof(addr));
2704 if (!string_format(p, pend - p - 1, "%s%s",
2705 (optcount == 0)? ":" : "@", inet_ntoa(addr)))
2711 adptr += sizeof(struct in_addr);
2720 if (pend - p < 4 + 3*opt[1]) { opt = NULL; break; }
2723 for (i = 0; i < opt[1]; i++)
2724 p += sprintf(CS p, "%2.2x ", opt[i]);
2733 log_write(0, LOG_MAIN, "%s", big_buffer);
2735 /* Refuse any call with IP options. This is what tcpwrappers 7.5 does. */
2737 log_write(0, LOG_MAIN|LOG_REJECT,
2738 "connection from %s refused (IP options)", host_and_ident(FALSE));
2740 smtp_printf("554 SMTP service not available\r\n", FALSE);
2744 /* Length of options = 0 => there are no options */
2746 else DEBUG(D_receive) debug_printf("no IP options found\n");
2748 #endif /* HAVE_IPV6 && !defined(NO_IP_OPTIONS) */
2750 /* Set keep-alive in socket options. The option is on by default. This
2751 setting is an attempt to get rid of some hanging connections that stick in
2752 read() when the remote end (usually a dialup) goes away. */
2754 if (smtp_accept_keepalive && !f.sender_host_notsocket)
2755 ip_keepalive(fileno(smtp_out), sender_host_address, FALSE);
2757 /* If the current host matches host_lookup, set the name by doing a
2758 reverse lookup. On failure, sender_host_name will be NULL and
2759 host_lookup_failed will be TRUE. This may or may not be serious - optional
2762 if (verify_check_host(&host_lookup) == OK)
2764 (void)host_name_lookup();
2765 host_build_sender_fullhost();
2768 /* Delay this until we have the full name, if it is looked up. */
2770 set_process_info("handling incoming connection from %s",
2771 host_and_ident(FALSE));
2773 /* Expand smtp_receive_timeout, if needed */
2775 if (smtp_receive_timeout_s)
2778 if ( !(exp = expand_string(smtp_receive_timeout_s))
2780 || (smtp_receive_timeout = readconf_readtime(exp, 0, FALSE)) < 0
2782 log_write(0, LOG_MAIN|LOG_PANIC,
2783 "bad value for smtp_receive_timeout: '%s'", exp ? exp : US"");
2786 /* Test for explicit connection rejection */
2788 if (verify_check_host(&host_reject_connection) == OK)
2790 log_write(L_connection_reject, LOG_MAIN|LOG_REJECT, "refused connection "
2791 "from %s (host_reject_connection)", host_and_ident(FALSE));
2792 smtp_printf("554 SMTP service not available\r\n", FALSE);
2796 /* Test with TCP Wrappers if so configured. There is a problem in that
2797 hosts_ctl() returns 0 (deny) under a number of system failure circumstances,
2798 such as disks dying. In these cases, it is desirable to reject with a 4xx
2799 error instead of a 5xx error. There isn't a "right" way to detect such
2800 problems. The following kludge is used: errno is zeroed before calling
2801 hosts_ctl(). If the result is "reject", a 5xx error is given only if the
2802 value of errno is 0 or ENOENT (which happens if /etc/hosts.{allow,deny} does
2805 #ifdef USE_TCP_WRAPPERS
2807 if (!(tcp_wrappers_name = expand_string(tcp_wrappers_daemon_name)))
2808 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "Expansion of \"%s\" "
2809 "(tcp_wrappers_name) failed: %s", string_printing(tcp_wrappers_name),
2810 expand_string_message);
2812 if (!hosts_ctl(tcp_wrappers_name,
2813 sender_host_name ? CS sender_host_name : STRING_UNKNOWN,
2814 sender_host_address ? CS sender_host_address : STRING_UNKNOWN,
2815 sender_ident ? CS sender_ident : STRING_UNKNOWN))
2817 if (errno == 0 || errno == ENOENT)
2819 HDEBUG(D_receive) debug_printf("tcp wrappers rejection\n");
2820 log_write(L_connection_reject,
2821 LOG_MAIN|LOG_REJECT, "refused connection from %s "
2822 "(tcp wrappers)", host_and_ident(FALSE));
2823 smtp_printf("554 SMTP service not available\r\n", FALSE);
2827 int save_errno = errno;
2828 HDEBUG(D_receive) debug_printf("tcp wrappers rejected with unexpected "
2829 "errno value %d\n", save_errno);
2830 log_write(L_connection_reject,
2831 LOG_MAIN|LOG_REJECT, "temporarily refused connection from %s "
2832 "(tcp wrappers errno=%d)", host_and_ident(FALSE), save_errno);
2833 smtp_printf("451 Temporary local problem - please try later\r\n", FALSE);
2839 /* Check for reserved slots. The value of smtp_accept_count has already been
2840 incremented to include this process. */
2842 if (smtp_accept_max > 0 &&
2843 smtp_accept_count > smtp_accept_max - smtp_accept_reserve)
2845 if ((rc = verify_check_host(&smtp_reserve_hosts)) != OK)
2847 log_write(L_connection_reject,
2848 LOG_MAIN, "temporarily refused connection from %s: not in "
2849 "reserve list: connected=%d max=%d reserve=%d%s",
2850 host_and_ident(FALSE), smtp_accept_count - 1, smtp_accept_max,
2851 smtp_accept_reserve, (rc == DEFER)? " (lookup deferred)" : "");
2852 smtp_printf("421 %s: Too many concurrent SMTP connections; "
2853 "please try again later\r\n", FALSE, smtp_active_hostname);
2856 reserved_host = TRUE;
2859 /* If a load level above which only messages from reserved hosts are
2860 accepted is set, check the load. For incoming calls via the daemon, the
2861 check is done in the superior process if there are no reserved hosts, to
2862 save a fork. In all cases, the load average will already be available
2863 in a global variable at this point. */
2865 if (smtp_load_reserve >= 0 &&
2866 load_average > smtp_load_reserve &&
2868 verify_check_host(&smtp_reserve_hosts) != OK)
2870 log_write(L_connection_reject,
2871 LOG_MAIN, "temporarily refused connection from %s: not in "
2872 "reserve list and load average = %.2f", host_and_ident(FALSE),
2873 (double)load_average/1000.0);
2874 smtp_printf("421 %s: Too much load; please try again later\r\n", FALSE,
2875 smtp_active_hostname);
2879 /* Determine whether unqualified senders or recipients are permitted
2880 for this host. Unfortunately, we have to do this every time, in order to
2881 set the flags so that they can be inspected when considering qualifying
2882 addresses in the headers. For a site that permits no qualification, this
2883 won't take long, however. */
2885 f.allow_unqualified_sender =
2886 verify_check_host(&sender_unqualified_hosts) == OK;
2888 f.allow_unqualified_recipient =
2889 verify_check_host(&recipient_unqualified_hosts) == OK;
2891 /* Determine whether HELO/EHLO is required for this host. The requirement
2892 can be hard or soft. */
2894 fl.helo_required = verify_check_host(&helo_verify_hosts) == OK;
2895 if (!fl.helo_required)
2896 fl.helo_verify = verify_check_host(&helo_try_verify_hosts) == OK;
2898 /* Determine whether this hosts is permitted to send syntactic junk
2899 after a HELO or EHLO command. */
2901 fl.helo_accept_junk = verify_check_host(&helo_accept_junk_hosts) == OK;
2904 /* For batch SMTP input we are now done. */
2906 if (smtp_batched_input) return TRUE;
2908 /* If valid Proxy Protocol source is connecting, set up session.
2909 * Failure will not allow any SMTP function other than QUIT. */
2911 #ifdef SUPPORT_PROXY
2912 proxy_session = FALSE;
2913 f.proxy_session_failed = FALSE;
2914 if (check_proxy_protocol_host())
2915 setup_proxy_protocol_host();
2918 /* Start up TLS if tls_on_connect is set. This is for supporting the legacy
2919 smtps port for use with older style SSL MTAs. */
2922 if (tls_in.on_connect)
2924 if (tls_server_start(tls_require_ciphers, &user_msg) != OK)
2925 return smtp_log_tls_fail(user_msg);
2926 cmd_list[CMD_LIST_TLS_AUTH].is_mail_cmd = TRUE;
2930 /* Run the connect ACL if it exists */
2933 if (acl_smtp_connect)
2936 if ((rc = acl_check(ACL_WHERE_CONNECT, NULL, acl_smtp_connect, &user_msg,
2939 (void) smtp_handle_acl_fail(ACL_WHERE_CONNECT, rc, user_msg, log_msg);
2944 /* Output the initial message for a two-way SMTP connection. It may contain
2945 newlines, which then cause a multi-line response to be given. */
2947 code = US"220"; /* Default status code */
2948 esc = US""; /* Default extended status code */
2949 esclen = 0; /* Length of esc */
2953 if (!(s = expand_string(smtp_banner)))
2954 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "Expansion of \"%s\" (smtp_banner) "
2955 "failed: %s", smtp_banner, expand_string_message);
2961 smtp_message_code(&code, &codelen, &s, NULL, TRUE);
2965 esclen = codelen - 4;
2969 /* Remove any terminating newlines; might as well remove trailing space too */
2972 while (p > s && isspace(p[-1])) p--;
2975 /* It seems that CC:Mail is braindead, and assumes that the greeting message
2976 is all contained in a single IP packet. The original code wrote out the
2977 greeting using several calls to fprint/fputc, and on busy servers this could
2978 cause it to be split over more than one packet - which caused CC:Mail to fall
2979 over when it got the second part of the greeting after sending its first
2980 command. Sigh. To try to avoid this, build the complete greeting message
2981 first, and output it in one fell swoop. This gives a better chance of it
2982 ending up as a single packet. */
2984 ss = string_get(256);
2987 do /* At least once, in case we have an empty string */
2990 uschar *linebreak = Ustrchr(p, '\n');
2991 ss = string_catn(ss, code, 3);
2995 ss = string_catn(ss, US" ", 1);
2999 len = linebreak - p;
3000 ss = string_catn(ss, US"-", 1);
3002 ss = string_catn(ss, esc, esclen);
3003 ss = string_catn(ss, p, len);
3004 ss = string_catn(ss, US"\r\n", 2);
3010 /* Before we write the banner, check that there is no input pending, unless
3011 this synchronisation check is disabled. */
3013 #ifdef EXPERIMENTAL_PIPE_CONNECT
3014 fl.pipe_connect_acceptable =
3015 sender_host_address && verify_check_host(&pipe_connect_advertise_hosts) == OK;
3018 if (fl.pipe_connect_acceptable)
3019 f.smtp_in_early_pipe_used = TRUE;
3025 unsigned n = smtp_inend - smtp_inptr;
3028 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP protocol "
3029 "synchronization error (input sent without waiting for greeting): "
3030 "rejected connection from %s input=\"%s\"", host_and_ident(TRUE),
3031 string_printing(string_copyn(smtp_inptr, n)));
3032 smtp_printf("554 SMTP synchronization error\r\n", FALSE);
3036 /* Now output the banner */
3037 /*XXX the ehlo-resp code does its own tls/nontls bit. Maybe subroutine that? */
3040 #ifdef EXPERIMENTAL_PIPE_CONNECT
3041 fl.pipe_connect_acceptable && pipeline_connect_sends(),
3045 string_from_gstring(ss));
3047 /* Attempt to see if we sent the banner before the last ACK of the 3-way
3048 handshake arrived. If so we must have managed a TFO. */
3061 /*************************************************
3062 * Handle SMTP syntax and protocol errors *
3063 *************************************************/
3065 /* Write to the log for SMTP syntax errors in incoming commands, if configured
3066 to do so. Then transmit the error response. The return value depends on the
3067 number of syntax and protocol errors in this SMTP session.
3070 type error type, given as a log flag bit
3071 code response code; <= 0 means don't send a response
3072 data data to reflect in the response (can be NULL)
3073 errmess the error message
3075 Returns: -1 limit of syntax/protocol errors NOT exceeded
3076 +1 limit of syntax/protocol errors IS exceeded
3078 These values fit in with the values of the "done" variable in the main
3079 processing loop in smtp_setup_msg(). */
3082 synprot_error(int type, int code, uschar *data, uschar *errmess)
3086 log_write(type, LOG_MAIN, "SMTP %s error in \"%s\" %s %s",
3087 (type == L_smtp_syntax_error)? "syntax" : "protocol",
3088 string_printing(smtp_cmd_buffer), host_and_ident(TRUE), errmess);
3090 if (++synprot_error_count > smtp_max_synprot_errors)
3093 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
3094 "syntax or protocol errors (last command was \"%s\")",
3095 host_and_ident(FALSE), string_printing(smtp_cmd_buffer));
3100 smtp_printf("%d%c%s%s%s\r\n", FALSE, code, yield == 1 ? '-' : ' ',
3101 data ? data : US"", data ? US": " : US"", errmess);
3103 smtp_printf("%d Too many syntax or protocol errors\r\n", FALSE, code);
3112 /*************************************************
3113 * Send SMTP response, possibly multiline *
3114 *************************************************/
3116 /* There are, it seems, broken clients out there that cannot handle multiline
3117 responses. If no_multiline_responses is TRUE (it can be set from an ACL), we
3118 output nothing for non-final calls, and only the first line for anything else.
3121 code SMTP code, may involve extended status codes
3122 codelen length of smtp code; if > 4 there's an ESC
3123 final FALSE if the last line isn't the final line
3124 msg message text, possibly containing newlines
3130 smtp_respond(uschar* code, int codelen, BOOL final, uschar *msg)
3135 if (!final && f.no_multiline_responses) return;
3140 esclen = codelen - 4;
3143 /* If this is the first output for a (non-batch) RCPT command, see if all RCPTs
3144 have had the same. Note: this code is also present in smtp_printf(). It would
3145 be tidier to have it only in one place, but when it was added, it was easier to
3146 do it that way, so as not to have to mess with the code for the RCPT command,
3147 which sometimes uses smtp_printf() and sometimes smtp_respond(). */
3149 if (fl.rcpt_in_progress)
3151 if (rcpt_smtp_response == NULL)
3152 rcpt_smtp_response = string_copy(msg);
3153 else if (fl.rcpt_smtp_response_same &&
3154 Ustrcmp(rcpt_smtp_response, msg) != 0)
3155 fl.rcpt_smtp_response_same = FALSE;
3156 fl.rcpt_in_progress = FALSE;
3159 /* Now output the message, splitting it up into multiple lines if necessary.
3160 We only handle pipelining these responses as far as nonfinal/final groups,
3161 not the whole MAIL/RCPT/DATA response set. */
3165 uschar *nl = Ustrchr(msg, '\n');
3168 smtp_printf("%.3s%c%.*s%s\r\n", !final, code, final ? ' ':'-', esclen, esc, msg);
3171 else if (nl[1] == 0 || f.no_multiline_responses)
3173 smtp_printf("%.3s%c%.*s%.*s\r\n", !final, code, final ? ' ':'-', esclen, esc,
3174 (int)(nl - msg), msg);
3179 smtp_printf("%.3s-%.*s%.*s\r\n", TRUE, code, esclen, esc, (int)(nl - msg), msg);
3181 while (isspace(*msg)) msg++;
3189 /*************************************************
3190 * Parse user SMTP message *
3191 *************************************************/
3193 /* This function allows for user messages overriding the response code details
3194 by providing a suitable response code string at the start of the message
3195 user_msg. Check the message for starting with a response code and optionally an
3196 extended status code. If found, check that the first digit is valid, and if so,
3197 change the code pointer and length to use the replacement. An invalid code
3198 causes a panic log; in this case, if the log messages is the same as the user
3199 message, we must also adjust the value of the log message to show the code that
3200 is actually going to be used (the original one).
3202 This function is global because it is called from receive.c as well as within
3205 Note that the code length returned includes the terminating whitespace
3206 character, which is always included in the regex match.
3209 code SMTP code, may involve extended status codes
3210 codelen length of smtp code; if > 4 there's an ESC
3212 log_msg optional log message, to be adjusted with the new SMTP code
3213 check_valid if true, verify the response code
3219 smtp_message_code(uschar **code, int *codelen, uschar **msg, uschar **log_msg,
3225 if (!msg || !*msg) return;
3227 if ((n = pcre_exec(regex_smtp_code, NULL, CS *msg, Ustrlen(*msg), 0,
3228 PCRE_EOPT, ovector, sizeof(ovector)/sizeof(int))) < 0) return;
3230 if (check_valid && (*msg)[0] != (*code)[0])
3232 log_write(0, LOG_MAIN|LOG_PANIC, "configured error code starts with "
3233 "incorrect digit (expected %c) in \"%s\"", (*code)[0], *msg);
3234 if (log_msg != NULL && *log_msg == *msg)
3235 *log_msg = string_sprintf("%s %s", *code, *log_msg + ovector[1]);
3240 *codelen = ovector[1]; /* Includes final space */
3242 *msg += ovector[1]; /* Chop the code off the message */
3249 /*************************************************
3250 * Handle an ACL failure *
3251 *************************************************/
3253 /* This function is called when acl_check() fails. As well as calls from within
3254 this module, it is called from receive.c for an ACL after DATA. It sorts out
3255 logging the incident, and sends the error response. A message containing
3256 newlines is turned into a multiline SMTP response, but for logging, only the
3259 There's a table of default permanent failure response codes to use in
3260 globals.c, along with the table of names. VFRY is special. Despite RFC1123 it
3261 defaults disabled in Exim. However, discussion in connection with RFC 821bis
3262 (aka RFC 2821) has concluded that the response should be 252 in the disabled
3263 state, because there are broken clients that try VRFY before RCPT. A 5xx
3264 response should be given only when the address is positively known to be
3265 undeliverable. Sigh. We return 252 if there is no VRFY ACL or it provides
3266 no explicit code, but if there is one we let it know best.
3267 Also, for ETRN, 458 is given on refusal, and for AUTH, 503.
3269 From Exim 4.63, it is possible to override the response code details by
3270 providing a suitable response code string at the start of the message provided
3271 in user_msg. The code's first digit is checked for validity.
3274 where where the ACL was called from
3276 user_msg a message that can be included in an SMTP response
3277 log_msg a message for logging
3279 Returns: 0 in most cases
3280 2 if the failure code was FAIL_DROP, in which case the
3281 SMTP connection should be dropped (this value fits with the
3282 "done" variable in smtp_setup_msg() below)
3286 smtp_handle_acl_fail(int where, int rc, uschar *user_msg, uschar *log_msg)
3288 BOOL drop = rc == FAIL_DROP;
3292 uschar *sender_info = US"";
3294 #ifdef WITH_CONTENT_SCAN
3295 where == ACL_WHERE_MIME ? US"during MIME ACL checks" :
3297 where == ACL_WHERE_PREDATA ? US"DATA" :
3298 where == ACL_WHERE_DATA ? US"after DATA" :
3299 #ifndef DISABLE_PRDR
3300 where == ACL_WHERE_PRDR ? US"after DATA PRDR" :
3303 string_sprintf("%s %s", acl_wherenames[where], smtp_cmd_data) :
3304 string_sprintf("%s in \"connect\" ACL", acl_wherenames[where]);
3306 if (drop) rc = FAIL;
3308 /* Set the default SMTP code, and allow a user message to change it. */
3310 smtp_code = rc == FAIL ? acl_wherecodes[where] : US"451";
3311 smtp_message_code(&smtp_code, &codelen, &user_msg, &log_msg,
3312 where != ACL_WHERE_VRFY);
3314 /* We used to have sender_address here; however, there was a bug that was not
3315 updating sender_address after a rewrite during a verify. When this bug was
3316 fixed, sender_address at this point became the rewritten address. I'm not sure
3317 this is what should be logged, so I've changed to logging the unrewritten
3318 address to retain backward compatibility. */
3320 #ifndef WITH_CONTENT_SCAN
3321 if (where == ACL_WHERE_RCPT || where == ACL_WHERE_DATA)
3323 if (where == ACL_WHERE_RCPT || where == ACL_WHERE_DATA || where == ACL_WHERE_MIME)
3326 sender_info = string_sprintf("F=<%s>%s%s%s%s ",
3327 sender_address_unrewritten ? sender_address_unrewritten : sender_address,
3328 sender_host_authenticated ? US" A=" : US"",
3329 sender_host_authenticated ? sender_host_authenticated : US"",
3330 sender_host_authenticated && authenticated_id ? US":" : US"",
3331 sender_host_authenticated && authenticated_id ? authenticated_id : US""
3335 /* If there's been a sender verification failure with a specific message, and
3336 we have not sent a response about it yet, do so now, as a preliminary line for
3337 failures, but not defers. However, always log it for defer, and log it for fail
3338 unless the sender_verify_fail log selector has been turned off. */
3340 if (sender_verified_failed &&
3341 !testflag(sender_verified_failed, af_sverify_told))
3343 BOOL save_rcpt_in_progress = fl.rcpt_in_progress;
3344 fl.rcpt_in_progress = FALSE; /* So as not to treat these as the error */
3346 setflag(sender_verified_failed, af_sverify_told);
3348 if (rc != FAIL || LOGGING(sender_verify_fail))
3349 log_write(0, LOG_MAIN|LOG_REJECT, "%s sender verify %s for <%s>%s",
3350 host_and_ident(TRUE),
3351 ((sender_verified_failed->special_action & 255) == DEFER)? "defer":"fail",
3352 sender_verified_failed->address,
3353 (sender_verified_failed->message == NULL)? US"" :
3354 string_sprintf(": %s", sender_verified_failed->message));
3356 if (rc == FAIL && sender_verified_failed->user_message)
3357 smtp_respond(smtp_code, codelen, FALSE, string_sprintf(
3358 testflag(sender_verified_failed, af_verify_pmfail)?
3359 "Postmaster verification failed while checking <%s>\n%s\n"
3360 "Several RFCs state that you are required to have a postmaster\n"
3361 "mailbox for each mail domain. This host does not accept mail\n"
3362 "from domains whose servers reject the postmaster address."
3364 testflag(sender_verified_failed, af_verify_nsfail)?
3365 "Callback setup failed while verifying <%s>\n%s\n"
3366 "The initial connection, or a HELO or MAIL FROM:<> command was\n"
3367 "rejected. Refusing MAIL FROM:<> does not help fight spam, disregards\n"
3368 "RFC requirements, and stops you from receiving standard bounce\n"
3369 "messages. This host does not accept mail from domains whose servers\n"
3372 "Verification failed for <%s>\n%s",
3373 sender_verified_failed->address,
3374 sender_verified_failed->user_message));
3376 fl.rcpt_in_progress = save_rcpt_in_progress;
3379 /* Sort out text for logging */
3381 log_msg = log_msg ? string_sprintf(": %s", log_msg) : US"";
3382 if ((lognl = Ustrchr(log_msg, '\n'))) *lognl = 0;
3384 /* Send permanent failure response to the command, but the code used isn't
3385 always a 5xx one - see comments at the start of this function. If the original
3386 rc was FAIL_DROP we drop the connection and yield 2. */
3389 smtp_respond(smtp_code, codelen, TRUE,
3390 user_msg ? user_msg : US"Administrative prohibition");
3392 /* Send temporary failure response to the command. Don't give any details,
3393 unless acl_temp_details is set. This is TRUE for a callout defer, a "defer"
3394 verb, and for a header verify when smtp_return_error_details is set.
3396 This conditional logic is all somewhat of a mess because of the odd
3397 interactions between temp_details and return_error_details. One day it should
3398 be re-implemented in a tidier fashion. */
3401 if (f.acl_temp_details && user_msg)
3403 if ( smtp_return_error_details
3404 && sender_verified_failed
3405 && sender_verified_failed->message
3407 smtp_respond(smtp_code, codelen, FALSE, sender_verified_failed->message);
3409 smtp_respond(smtp_code, codelen, TRUE, user_msg);
3412 smtp_respond(smtp_code, codelen, TRUE,
3413 US"Temporary local problem - please try later");
3415 /* Log the incident to the logs that are specified by log_reject_target
3416 (default main, reject). This can be empty to suppress logging of rejections. If
3417 the connection is not forcibly to be dropped, return 0. Otherwise, log why it
3418 is closing if required and return 2. */
3420 if (log_reject_target != 0)
3423 gstring * g = s_tlslog(NULL);
3424 uschar * tls = string_from_gstring(g);
3425 if (!tls) tls = US"";
3427 uschar * tls = US"";
3429 log_write(where == ACL_WHERE_CONNECT ? L_connection_reject : 0,
3430 log_reject_target, "%s%s%s %s%srejected %s%s",
3431 LOGGING(dnssec) && sender_host_dnssec ? US" DS" : US"",
3432 host_and_ident(TRUE),
3435 rc == FAIL ? US"" : US"temporarily ",
3439 if (!drop) return 0;
3441 log_write(L_smtp_connection, LOG_MAIN, "%s closed by DROP in ACL",
3442 smtp_get_connection_info());
3444 /* Run the not-quit ACL, but without any custom messages. This should not be a
3445 problem, because we get here only if some other ACL has issued "drop", and
3446 in that case, *its* custom messages will have been used above. */
3448 smtp_notquit_exit(US"acl-drop", NULL, NULL);
3455 /*************************************************
3456 * Handle SMTP exit when QUIT is not given *
3457 *************************************************/
3459 /* This function provides a logging/statistics hook for when an SMTP connection
3460 is dropped on the floor or the other end goes away. It's a global function
3461 because it's called from receive.c as well as this module. As well as running
3462 the NOTQUIT ACL, if there is one, this function also outputs a final SMTP
3463 response, either with a custom message from the ACL, or using a default. There
3464 is one case, however, when no message is output - after "drop". In that case,
3465 the ACL that obeyed "drop" has already supplied the custom message, and NULL is
3466 passed to this function.
3468 In case things go wrong while processing this function, causing an error that
3469 may re-enter this function, there is a recursion check.
3472 reason What $smtp_notquit_reason will be set to in the ACL;
3473 if NULL, the ACL is not run
3474 code The error code to return as part of the response
3475 defaultrespond The default message if there's no user_msg
3481 smtp_notquit_exit(uschar *reason, uschar *code, uschar *defaultrespond, ...)
3484 uschar *user_msg = NULL;
3485 uschar *log_msg = NULL;
3487 /* Check for recursive call */
3489 if (fl.smtp_exit_function_called)
3491 log_write(0, LOG_PANIC, "smtp_notquit_exit() called more than once (%s)",
3495 fl.smtp_exit_function_called = TRUE;
3497 /* Call the not-QUIT ACL, if there is one, unless no reason is given. */
3499 if (acl_smtp_notquit && reason)
3501 smtp_notquit_reason = reason;
3502 if ((rc = acl_check(ACL_WHERE_NOTQUIT, NULL, acl_smtp_notquit, &user_msg,
3503 &log_msg)) == ERROR)
3504 log_write(0, LOG_MAIN|LOG_PANIC, "ACL for not-QUIT returned ERROR: %s",
3508 /* If the connection was dropped, we certainly are no longer talking TLS */
3509 tls_in.active.sock = -1;
3511 /* Write an SMTP response if we are expected to give one. As the default
3512 responses are all internal, they should be reasonable size. */
3514 if (code && defaultrespond)
3517 smtp_respond(code, 3, TRUE, user_msg);
3523 va_start(ap, defaultrespond);
3524 g = string_vformat(NULL, TRUE, CS defaultrespond, ap);
3526 smtp_printf("%s %s\r\n", FALSE, code, string_from_gstring(g));
3535 /*************************************************
3536 * Verify HELO argument *
3537 *************************************************/
3539 /* This function is called if helo_verify_hosts or helo_try_verify_hosts is
3540 matched. It is also called from ACL processing if verify = helo is used and
3541 verification was not previously tried (i.e. helo_try_verify_hosts was not
3542 matched). The result of its processing is to set helo_verified and
3543 helo_verify_failed. These variables should both be FALSE for this function to
3546 Note that EHLO/HELO is legitimately allowed to quote an address literal. Allow
3547 for IPv6 ::ffff: literals.
3550 Returns: TRUE if testing was completed;
3551 FALSE on a temporary failure
3555 smtp_verify_helo(void)
3559 HDEBUG(D_receive) debug_printf("verifying EHLO/HELO argument \"%s\"\n",
3562 if (sender_helo_name == NULL)
3564 HDEBUG(D_receive) debug_printf("no EHLO/HELO command was issued\n");
3567 /* Deal with the case of -bs without an IP address */
3569 else if (sender_host_address == NULL)
3571 HDEBUG(D_receive) debug_printf("no client IP address: assume success\n");
3572 f.helo_verified = TRUE;
3575 /* Deal with the more common case when there is a sending IP address */
3577 else if (sender_helo_name[0] == '[')
3579 f.helo_verified = Ustrncmp(sender_helo_name+1, sender_host_address,
3580 Ustrlen(sender_host_address)) == 0;
3583 if (!f.helo_verified)
3585 if (strncmpic(sender_host_address, US"::ffff:", 7) == 0)
3586 f.helo_verified = Ustrncmp(sender_helo_name + 1,
3587 sender_host_address + 7, Ustrlen(sender_host_address) - 7) == 0;
3592 { if (f.helo_verified) debug_printf("matched host address\n"); }
3595 /* Do a reverse lookup if one hasn't already given a positive or negative
3596 response. If that fails, or the name doesn't match, try checking with a forward
3601 if (sender_host_name == NULL && !host_lookup_failed)
3602 yield = host_name_lookup() != DEFER;
3604 /* If a host name is known, check it and all its aliases. */
3606 if (sender_host_name)
3607 if ((f.helo_verified = strcmpic(sender_host_name, sender_helo_name) == 0))
3609 sender_helo_dnssec = sender_host_dnssec;
3610 HDEBUG(D_receive) debug_printf("matched host name\n");
3614 uschar **aliases = sender_host_aliases;
3616 if ((f.helo_verified = strcmpic(*aliases++, sender_helo_name) == 0))
3618 sender_helo_dnssec = sender_host_dnssec;
3622 HDEBUG(D_receive) if (f.helo_verified)
3623 debug_printf("matched alias %s\n", *(--aliases));
3626 /* Final attempt: try a forward lookup of the helo name */
3628 if (!f.helo_verified)
3635 h.name = sender_helo_name;
3642 HDEBUG(D_receive) debug_printf("getting IP address for %s\n",
3644 rc = host_find_bydns(&h, NULL, HOST_FIND_BY_A | HOST_FIND_BY_AAAA,
3645 NULL, NULL, NULL, &d, NULL, NULL);
3646 if (rc == HOST_FOUND || rc == HOST_FOUND_LOCAL)
3647 for (hh = &h; hh; hh = hh->next)
3648 if (Ustrcmp(hh->address, sender_host_address) == 0)
3650 f.helo_verified = TRUE;
3651 if (h.dnssec == DS_YES) sender_helo_dnssec = TRUE;
3654 debug_printf("IP address for %s matches calling address\n"
3655 "Forward DNS security status: %sverified\n",
3656 sender_helo_name, sender_helo_dnssec ? "" : "un");
3663 if (!f.helo_verified) f.helo_verify_failed = TRUE; /* We've tried ... */
3670 /*************************************************
3671 * Send user response message *
3672 *************************************************/
3674 /* This function is passed a default response code and a user message. It calls
3675 smtp_message_code() to check and possibly modify the response code, and then
3676 calls smtp_respond() to transmit the response. I put this into a function
3677 just to avoid a lot of repetition.
3680 code the response code
3681 user_msg the user message
3687 smtp_user_msg(uschar *code, uschar *user_msg)
3690 smtp_message_code(&code, &len, &user_msg, NULL, TRUE);
3691 smtp_respond(code, len, TRUE, user_msg);
3697 smtp_in_auth(auth_instance *au, uschar ** s, uschar ** ss)
3699 const uschar *set_id = NULL;
3702 /* Run the checking code, passing the remainder of the command line as
3703 data. Initials the $auth<n> variables as empty. Initialize $0 empty and set
3704 it as the only set numerical variable. The authenticator may set $auth<n>
3705 and also set other numeric variables. The $auth<n> variables are preferred
3706 nowadays; the numerical variables remain for backwards compatibility.
3708 Afterwards, have a go at expanding the set_id string, even if
3709 authentication failed - for bad passwords it can be useful to log the
3710 userid. On success, require set_id to expand and exist, and put it in
3711 authenticated_id. Save this in permanent store, as the working store gets
3712 reset at HELO, RSET, etc. */
3714 for (i = 0; i < AUTH_VARS; i++) auth_vars[i] = NULL;
3716 expand_nlength[0] = 0; /* $0 contains nothing */
3718 rc = (au->info->servercode)(au, smtp_cmd_data);
3719 if (au->set_id) set_id = expand_string(au->set_id);
3720 expand_nmax = -1; /* Reset numeric variables */
3721 for (i = 0; i < AUTH_VARS; i++) auth_vars[i] = NULL; /* Reset $auth<n> */
3723 /* The value of authenticated_id is stored in the spool file and printed in
3724 log lines. It must not contain binary zeros or newline characters. In
3725 normal use, it never will, but when playing around or testing, this error
3726 can (did) happen. To guard against this, ensure that the id contains only
3727 printing characters. */
3729 if (set_id) set_id = string_printing(set_id);
3731 /* For the non-OK cases, set up additional logging data if set_id
3735 set_id = set_id && *set_id
3736 ? string_sprintf(" (set_id=%s)", set_id) : US"";
3738 /* Switch on the result */
3743 if (!au->set_id || set_id) /* Complete success */
3745 if (set_id) authenticated_id = string_copy_malloc(set_id);
3746 sender_host_authenticated = au->name;
3747 sender_host_auth_pubname = au->public_name;
3748 authentication_failed = FALSE;
3749 authenticated_fail_id = NULL; /* Impossible to already be set? */
3752 (sender_host_address ? protocols : protocols_local)
3753 [pextend + pauthed + (tls_in.active.sock >= 0 ? pcrpted:0)];
3754 *s = *ss = US"235 Authentication succeeded";
3755 authenticated_by = au;
3759 /* Authentication succeeded, but we failed to expand the set_id string.
3760 Treat this as a temporary error. */
3762 auth_defer_msg = expand_string_message;
3766 if (set_id) authenticated_fail_id = string_copy_malloc(set_id);
3767 *s = string_sprintf("435 Unable to authenticate at present%s",
3768 auth_defer_user_msg);
3769 *ss = string_sprintf("435 Unable to authenticate at present%s: %s",
3770 set_id, auth_defer_msg);
3774 *s = *ss = US"501 Invalid base64 data";
3778 *s = *ss = US"501 Authentication cancelled";
3782 *s = *ss = US"553 Initial data not expected";
3786 if (set_id) authenticated_fail_id = string_copy_malloc(set_id);
3787 *s = US"535 Incorrect authentication data";
3788 *ss = string_sprintf("535 Incorrect authentication data%s", set_id);
3792 if (set_id) authenticated_fail_id = string_copy_malloc(set_id);
3793 *s = US"435 Internal error";
3794 *ss = string_sprintf("435 Internal error%s: return %d from authentication "
3795 "check", set_id, rc);
3807 qualify_recipient(uschar ** recipient, uschar * smtp_cmd_data, uschar * tag)
3810 if (f.allow_unqualified_recipient || strcmpic(*recipient, US"postmaster") == 0)
3812 DEBUG(D_receive) debug_printf("unqualified address %s accepted\n",
3814 rd = Ustrlen(recipient) + 1;
3815 *recipient = rewrite_address_qualify(*recipient, TRUE);
3818 smtp_printf("501 %s: recipient address must contain a domain\r\n", FALSE,
3820 log_write(L_smtp_syntax_error,
3821 LOG_MAIN|LOG_REJECT, "unqualified %s rejected: <%s> %s%s",
3822 tag, *recipient, host_and_ident(TRUE), host_lookup_msg);
3830 smtp_quit_handler(uschar ** user_msgp, uschar ** log_msgp)
3833 incomplete_transaction_log(US"QUIT");
3836 int rc = acl_check(ACL_WHERE_QUIT, NULL, acl_smtp_quit, user_msgp, log_msgp);
3838 log_write(0, LOG_MAIN|LOG_PANIC, "ACL for QUIT returned ERROR: %s",
3842 smtp_respond(US"221", 3, TRUE, *user_msgp);
3844 smtp_printf("221 %s closing connection\r\n", FALSE, smtp_active_hostname);
3847 tls_close(NULL, TLS_SHUTDOWN_NOWAIT);
3850 log_write(L_smtp_connection, LOG_MAIN, "%s closed by QUIT",
3851 smtp_get_connection_info());
3856 smtp_rset_handler(void)
3859 incomplete_transaction_log(US"RSET");
3860 smtp_printf("250 Reset OK\r\n", FALSE);
3861 cmd_list[CMD_LIST_RSET].is_mail_cmd = FALSE;
3866 /*************************************************
3867 * Initialize for SMTP incoming message *
3868 *************************************************/
3870 /* This function conducts the initial dialogue at the start of an incoming SMTP
3871 message, and builds a list of recipients. However, if the incoming message
3872 is part of a batch (-bS option) a separate function is called since it would
3873 be messy having tests splattered about all over this function. This function
3874 therefore handles the case where interaction is occurring. The input and output
3875 files are set up in smtp_in and smtp_out.
3877 The global recipients_list is set to point to a vector of recipient_item
3878 blocks, whose number is given by recipients_count. This is extended by the
3879 receive_add_recipient() function. The global variable sender_address is set to
3880 the sender's address. The yield is +1 if a message has been successfully
3881 started, 0 if a QUIT command was encountered or the connection was refused from
3882 the particular host, or -1 if the connection was lost.
3886 Returns: > 0 message successfully started (reached DATA)
3887 = 0 QUIT read or end of file reached or call refused
3892 smtp_setup_msg(void)
3895 BOOL toomany = FALSE;
3896 BOOL discarded = FALSE;
3897 BOOL last_was_rej_mail = FALSE;
3898 BOOL last_was_rcpt = FALSE;
3899 void *reset_point = store_get(0);
3901 DEBUG(D_receive) debug_printf("smtp_setup_msg entered\n");
3903 /* Reset for start of new message. We allow one RSET not to be counted as a
3904 nonmail command, for those MTAs that insist on sending it between every
3905 message. Ditto for EHLO/HELO and for STARTTLS, to allow for going in and out of
3906 TLS between messages (an Exim client may do this if it has messages queued up
3907 for the host). Note: we do NOT reset AUTH at this point. */
3909 smtp_reset(reset_point);
3910 message_ended = END_NOTSTARTED;
3912 chunking_state = f.chunking_offered ? CHUNKING_OFFERED : CHUNKING_NOT_OFFERED;
3914 cmd_list[CMD_LIST_RSET].is_mail_cmd = TRUE;
3915 cmd_list[CMD_LIST_HELO].is_mail_cmd = TRUE;
3916 cmd_list[CMD_LIST_EHLO].is_mail_cmd = TRUE;
3918 cmd_list[CMD_LIST_STARTTLS].is_mail_cmd = TRUE;
3921 /* Set the local signal handler for SIGTERM - it tries to end off tidily */
3923 had_command_sigterm = 0;
3924 os_non_restarting_signal(SIGTERM, command_sigterm_handler);
3926 /* Batched SMTP is handled in a different function. */
3928 if (smtp_batched_input) return smtp_setup_batch_msg();
3930 /* Deal with SMTP commands. This loop is exited by setting done to a POSITIVE
3931 value. The values are 2 larger than the required yield of the function. */
3935 const uschar **argv;
3936 uschar *etrn_command;
3937 uschar *etrn_serialize_key;
3939 uschar *log_msg, *smtp_code;
3940 uschar *user_msg = NULL;
3941 uschar *recipient = NULL;
3942 uschar *hello = NULL;
3944 BOOL was_rej_mail = FALSE;
3945 BOOL was_rcpt = FALSE;
3946 void (*oldsignal)(int);
3948 int start, end, sender_domain, recipient_domain;
3952 uschar *orcpt = NULL;
3957 /* Check once per STARTTLS or SSL-on-connect for a TLS AUTH */
3958 if ( tls_in.active.sock >= 0
3960 && tls_in.certificate_verified
3961 && cmd_list[CMD_LIST_TLS_AUTH].is_mail_cmd
3964 cmd_list[CMD_LIST_TLS_AUTH].is_mail_cmd = FALSE;
3966 for (au = auths; au; au = au->next)
3967 if (strcmpic(US"tls", au->driver_name) == 0)
3970 && (rc = acl_check(ACL_WHERE_AUTH, NULL, acl_smtp_auth,
3971 &user_msg, &log_msg)) != OK
3973 done = smtp_handle_acl_fail(ACL_WHERE_AUTH, rc, user_msg, log_msg);
3976 smtp_cmd_data = NULL;
3978 if (smtp_in_auth(au, &s, &ss) == OK)
3979 { DEBUG(D_auth) debug_printf("tls auth succeeded\n"); }
3981 { DEBUG(D_auth) debug_printf("tls auth not succeeded\n"); }
3989 if (smtp_in) /* Avoid pure-ACKs while in cmd pingpong phase */
3990 (void) setsockopt(fileno(smtp_in), IPPROTO_TCP, TCP_QUICKACK,
3991 US &off, sizeof(off));
3994 switch(smtp_read_command(
3995 #ifdef EXPERIMENTAL_PIPE_CONNECT
3996 !fl.pipe_connect_acceptable,
4000 GETC_BUFFER_UNLIMITED))
4002 /* The AUTH command is not permitted to occur inside a transaction, and may
4003 occur successfully only once per connection. Actually, that isn't quite
4004 true. When TLS is started, all previous information about a connection must
4005 be discarded, so a new AUTH is permitted at that time.
4007 AUTH may only be used when it has been advertised. However, it seems that
4008 there are clients that send AUTH when it hasn't been advertised, some of
4009 them even doing this after HELO. And there are MTAs that accept this. Sigh.
4010 So there's a get-out that allows this to happen.
4012 AUTH is initially labelled as a "nonmail command" so that one occurrence
4013 doesn't get counted. We change the label here so that multiple failing
4014 AUTHS will eventually hit the nonmail threshold. */
4018 authentication_failed = TRUE;
4019 cmd_list[CMD_LIST_AUTH].is_mail_cmd = FALSE;
4021 if (!fl.auth_advertised && !f.allow_auth_unadvertised)
4023 done = synprot_error(L_smtp_protocol_error, 503, NULL,
4024 US"AUTH command used when not advertised");
4027 if (sender_host_authenticated)
4029 done = synprot_error(L_smtp_protocol_error, 503, NULL,
4030 US"already authenticated");
4035 done = synprot_error(L_smtp_protocol_error, 503, NULL,
4036 US"not permitted in mail transaction");
4043 && (rc = acl_check(ACL_WHERE_AUTH, NULL, acl_smtp_auth,
4044 &user_msg, &log_msg)) != OK
4047 done = smtp_handle_acl_fail(ACL_WHERE_AUTH, rc, user_msg, log_msg);
4051 /* Find the name of the requested authentication mechanism. */
4054 while ((c = *smtp_cmd_data) != 0 && !isspace(c))
4056 if (!isalnum(c) && c != '-' && c != '_')
4058 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4059 US"invalid character in authentication mechanism name");
4065 /* If not at the end of the line, we must be at white space. Terminate the
4066 name and move the pointer on to any data that may be present. */
4068 if (*smtp_cmd_data != 0)
4070 *smtp_cmd_data++ = 0;
4071 while (isspace(*smtp_cmd_data)) smtp_cmd_data++;
4074 /* Search for an authentication mechanism which is configured for use
4075 as a server and which has been advertised (unless, sigh, allow_auth_
4076 unadvertised is set). */
4078 for (au = auths; au; au = au->next)
4079 if (strcmpic(s, au->public_name) == 0 && au->server &&
4080 (au->advertised || f.allow_auth_unadvertised))
4085 c = smtp_in_auth(au, &s, &ss);
4087 smtp_printf("%s\r\n", FALSE, s);
4089 log_write(0, LOG_MAIN|LOG_REJECT, "%s authenticator failed for %s: %s",
4090 au->name, host_and_ident(FALSE), ss);
4093 done = synprot_error(L_smtp_protocol_error, 504, NULL,
4094 string_sprintf("%s authentication mechanism not supported", s));
4096 break; /* AUTH_CMD */
4098 /* The HELO/EHLO commands are permitted to appear in the middle of a
4099 session as well as at the beginning. They have the effect of a reset in
4100 addition to their other functions. Their absence at the start cannot be
4101 taken to be an error.
4105 If the EHLO command is not acceptable to the SMTP server, 501, 500,
4106 or 502 failure replies MUST be returned as appropriate. The SMTP
4107 server MUST stay in the same state after transmitting these replies
4108 that it was in before the EHLO was received.
4110 Therefore, we do not do the reset until after checking the command for
4111 acceptability. This change was made for Exim release 4.11. Previously
4112 it did the reset first. */
4125 HELO_EHLO: /* Common code for HELO and EHLO */
4126 cmd_list[CMD_LIST_HELO].is_mail_cmd = FALSE;
4127 cmd_list[CMD_LIST_EHLO].is_mail_cmd = FALSE;
4129 /* Reject the HELO if its argument was invalid or non-existent. A
4130 successful check causes the argument to be saved in malloc store. */
4132 if (!check_helo(smtp_cmd_data))
4134 smtp_printf("501 Syntactically invalid %s argument(s)\r\n", FALSE, hello);
4136 log_write(0, LOG_MAIN|LOG_REJECT, "rejected %s from %s: syntactically "
4137 "invalid argument(s): %s", hello, host_and_ident(FALSE),
4138 *smtp_cmd_argument == 0 ? US"(no argument given)" :
4139 string_printing(smtp_cmd_argument));
4141 if (++synprot_error_count > smtp_max_synprot_errors)
4143 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
4144 "syntax or protocol errors (last command was \"%s\")",
4145 host_and_ident(FALSE), string_printing(smtp_cmd_buffer));
4152 /* If sender_host_unknown is true, we have got here via the -bs interface,
4153 not called from inetd. Otherwise, we are running an IP connection and the
4154 host address will be set. If the helo name is the primary name of this
4155 host and we haven't done a reverse lookup, force one now. If helo_required
4156 is set, ensure that the HELO name matches the actual host. If helo_verify
4157 is set, do the same check, but softly. */
4159 if (!f.sender_host_unknown)
4161 BOOL old_helo_verified = f.helo_verified;
4162 uschar *p = smtp_cmd_data;
4164 while (*p != 0 && !isspace(*p)) { *p = tolower(*p); p++; }
4167 /* Force a reverse lookup if HELO quoted something in helo_lookup_domains
4168 because otherwise the log can be confusing. */
4170 if ( !sender_host_name
4171 && match_isinlist(sender_helo_name, CUSS &helo_lookup_domains, 0,
4172 &domainlist_anchor, NULL, MCL_DOMAIN, TRUE, NULL) == OK)
4173 (void)host_name_lookup();
4175 /* Rebuild the fullhost info to include the HELO name (and the real name
4176 if it was looked up.) */
4178 host_build_sender_fullhost(); /* Rebuild */
4179 set_process_info("handling%s incoming connection from %s",
4180 tls_in.active.sock >= 0 ? " TLS" : "", host_and_ident(FALSE));
4182 /* Verify if configured. This doesn't give much security, but it does
4183 make some people happy to be able to do it. If helo_required is set,
4184 (host matches helo_verify_hosts) failure forces rejection. If helo_verify
4185 is set (host matches helo_try_verify_hosts), it does not. This is perhaps
4186 now obsolescent, since the verification can now be requested selectively
4189 f.helo_verified = f.helo_verify_failed = sender_helo_dnssec = FALSE;
4190 if (fl.helo_required || fl.helo_verify)
4192 BOOL tempfail = !smtp_verify_helo();
4193 if (!f.helo_verified)
4195 if (fl.helo_required)
4197 smtp_printf("%d %s argument does not match calling host\r\n", FALSE,
4198 tempfail? 451 : 550, hello);
4199 log_write(0, LOG_MAIN|LOG_REJECT, "%srejected \"%s %s\" from %s",
4200 tempfail? "temporarily " : "",
4201 hello, sender_helo_name, host_and_ident(FALSE));
4202 f.helo_verified = old_helo_verified;
4203 break; /* End of HELO/EHLO processing */
4205 HDEBUG(D_all) debug_printf("%s verification failed but host is in "
4206 "helo_try_verify_hosts\n", hello);
4212 /* set up SPF context */
4213 spf_init(sender_helo_name, sender_host_address);
4216 /* Apply an ACL check if one is defined; afterwards, recheck
4217 synchronization in case the client started sending in a delay. */
4220 if ((rc = acl_check(ACL_WHERE_HELO, NULL, acl_smtp_helo,
4221 &user_msg, &log_msg)) != OK)
4223 done = smtp_handle_acl_fail(ACL_WHERE_HELO, rc, user_msg, log_msg);
4224 if (sender_helo_name)
4226 store_free(sender_helo_name);
4227 sender_helo_name = NULL;
4229 host_build_sender_fullhost(); /* Rebuild */
4232 #ifdef EXPERIMENTAL_PIPE_CONNECT
4233 else if (!fl.pipe_connect_acceptable && !check_sync())
4235 else if (!check_sync())
4239 /* Generate an OK reply. The default string includes the ident if present,
4240 and also the IP address if present. Reflecting back the ident is intended
4241 as a deterrent to mail forgers. For maximum efficiency, and also because
4242 some broken systems expect each response to be in a single packet, arrange
4243 that the entire reply is sent in one write(). */
4245 fl.auth_advertised = FALSE;
4246 f.smtp_in_pipelining_advertised = FALSE;
4248 fl.tls_advertised = FALSE;
4249 # ifdef EXPERIMENTAL_REQUIRETLS
4250 fl.requiretls_advertised = FALSE;
4253 fl.dsn_advertised = FALSE;
4255 fl.smtputf8_advertised = FALSE;
4258 smtp_code = US"250 "; /* Default response code plus space*/
4261 g = string_fmt_append(NULL, "%.3s %s Hello %s%s%s",
4263 smtp_active_hostname,
4264 sender_ident ? sender_ident : US"",
4265 sender_ident ? US" at " : US"",
4266 sender_host_name ? sender_host_name : sender_helo_name);
4268 if (sender_host_address)
4269 g = string_fmt_append(g, " [%s]", sender_host_address);
4272 /* A user-supplied EHLO greeting may not contain more than one line. Note
4273 that the code returned by smtp_message_code() includes the terminating
4274 whitespace character. */
4280 smtp_message_code(&smtp_code, &codelen, &user_msg, NULL, TRUE);
4281 s = string_sprintf("%.*s%s", codelen, smtp_code, user_msg);
4282 if ((ss = strpbrk(CS s, "\r\n")) != NULL)
4284 log_write(0, LOG_MAIN|LOG_PANIC, "EHLO/HELO response must not contain "
4285 "newlines: message truncated: %s", string_printing(s));
4288 g = string_cat(NULL, s);
4291 g = string_catn(g, US"\r\n", 2);
4293 /* If we received EHLO, we must create a multiline response which includes
4294 the functions supported. */
4300 /* I'm not entirely happy with this, as an MTA is supposed to check
4301 that it has enough room to accept a message of maximum size before
4302 it sends this. However, there seems little point in not sending it.
4303 The actual size check happens later at MAIL FROM time. By postponing it
4304 till then, VRFY and EXPN can be used after EHLO when space is short. */
4306 if (thismessage_size_limit > 0)
4307 g = string_fmt_append(g, "%.3s-SIZE %d\r\n", smtp_code,
4308 thismessage_size_limit);
4311 g = string_catn(g, smtp_code, 3);
4312 g = string_catn(g, US"-SIZE\r\n", 7);
4315 /* Exim does not do protocol conversion or data conversion. It is 8-bit
4316 clean; if it has an 8-bit character in its hand, it just sends it. It
4317 cannot therefore specify 8BITMIME and remain consistent with the RFCs.
4318 However, some users want this option simply in order to stop MUAs
4319 mangling messages that contain top-bit-set characters. It is therefore
4320 provided as an option. */
4322 if (accept_8bitmime)
4324 g = string_catn(g, smtp_code, 3);
4325 g = string_catn(g, US"-8BITMIME\r\n", 11);
4328 /* Advertise DSN support if configured to do so. */
4329 if (verify_check_host(&dsn_advertise_hosts) != FAIL)
4331 g = string_catn(g, smtp_code, 3);
4332 g = string_catn(g, US"-DSN\r\n", 6);
4333 fl.dsn_advertised = TRUE;
4336 /* Advertise ETRN/VRFY/EXPN if there's are ACL checking whether a host is
4337 permitted to issue them; a check is made when any host actually tries. */
4341 g = string_catn(g, smtp_code, 3);
4342 g = string_catn(g, US"-ETRN\r\n", 7);
4346 g = string_catn(g, smtp_code, 3);
4347 g = string_catn(g, US"-VRFY\r\n", 7);
4351 g = string_catn(g, smtp_code, 3);
4352 g = string_catn(g, US"-EXPN\r\n", 7);
4355 /* Exim is quite happy with pipelining, so let the other end know that
4356 it is safe to use it, unless advertising is disabled. */
4358 if ( f.pipelining_enable
4359 && verify_check_host(&pipelining_advertise_hosts) == OK)
4361 g = string_catn(g, smtp_code, 3);
4362 g = string_catn(g, US"-PIPELINING\r\n", 13);
4363 sync_cmd_limit = NON_SYNC_CMD_PIPELINING;
4364 f.smtp_in_pipelining_advertised = TRUE;
4366 #ifdef EXPERIMENTAL_PIPE_CONNECT
4367 if (fl.pipe_connect_acceptable)
4369 f.smtp_in_early_pipe_advertised = TRUE;
4370 g = string_catn(g, smtp_code, 3);
4371 g = string_catn(g, US"-" EARLY_PIPE_FEATURE_NAME "\r\n", EARLY_PIPE_FEATURE_LEN+3);
4377 /* If any server authentication mechanisms are configured, advertise
4378 them if the current host is in auth_advertise_hosts. The problem with
4379 advertising always is that some clients then require users to
4380 authenticate (and aren't configurable otherwise) even though it may not
4381 be necessary (e.g. if the host is in host_accept_relay).
4383 RFC 2222 states that SASL mechanism names contain only upper case
4384 letters, so output the names in upper case, though we actually recognize
4385 them in either case in the AUTH command. */
4389 && !sender_host_authenticated
4391 && verify_check_host(&auth_advertise_hosts) == OK
4396 for (au = auths; au; au = au->next)
4398 au->advertised = FALSE;
4401 DEBUG(D_auth+D_expand) debug_printf_indent(
4402 "Evaluating advertise_condition for %s athenticator\n",
4404 if ( !au->advertise_condition
4405 || expand_check_condition(au->advertise_condition, au->name,
4412 g = string_catn(g, smtp_code, 3);
4413 g = string_catn(g, US"-AUTH", 5);
4415 fl.auth_advertised = TRUE;
4418 g = string_catn(g, US" ", 1);
4419 g = string_cat (g, au->public_name);
4420 while (++saveptr < g->ptr) g->s[saveptr] = toupper(g->s[saveptr]);
4421 au->advertised = TRUE;
4426 if (!first) g = string_catn(g, US"\r\n", 2);
4429 /* RFC 3030 CHUNKING */
4431 if (verify_check_host(&chunking_advertise_hosts) != FAIL)
4433 g = string_catn(g, smtp_code, 3);
4434 g = string_catn(g, US"-CHUNKING\r\n", 11);
4435 f.chunking_offered = TRUE;
4436 chunking_state = CHUNKING_OFFERED;
4439 /* Advertise TLS (Transport Level Security) aka SSL (Secure Socket Layer)
4440 if it has been included in the binary, and the host matches
4441 tls_advertise_hosts. We must *not* advertise if we are already in a
4442 secure connection. */
4445 if (tls_in.active.sock < 0 &&
4446 verify_check_host(&tls_advertise_hosts) != FAIL)
4448 g = string_catn(g, smtp_code, 3);
4449 g = string_catn(g, US"-STARTTLS\r\n", 11);
4450 fl.tls_advertised = TRUE;
4453 # ifdef EXPERIMENTAL_REQUIRETLS
4454 /* Advertise REQUIRETLS only once we are in a secure connection */
4455 if ( tls_in.active.sock >= 0
4456 && verify_check_host(&tls_advertise_requiretls) != FAIL)
4458 g = string_catn(g, smtp_code, 3);
4459 g = string_catn(g, US"-REQUIRETLS\r\n", 13);
4460 fl.requiretls_advertised = TRUE;
4465 #ifndef DISABLE_PRDR
4466 /* Per Recipient Data Response, draft by Eric A. Hall extending RFC */
4469 g = string_catn(g, smtp_code, 3);
4470 g = string_catn(g, US"-PRDR\r\n", 7);
4475 if ( accept_8bitmime
4476 && verify_check_host(&smtputf8_advertise_hosts) != FAIL)
4478 g = string_catn(g, smtp_code, 3);
4479 g = string_catn(g, US"-SMTPUTF8\r\n", 11);
4480 fl.smtputf8_advertised = TRUE;
4484 /* Finish off the multiline reply with one that is always available. */
4486 g = string_catn(g, smtp_code, 3);
4487 g = string_catn(g, US" HELP\r\n", 7);
4490 /* Terminate the string (for debug), write it, and note that HELO/EHLO
4494 if (tls_in.active.sock >= 0)
4495 (void)tls_write(NULL, g->s, g->ptr,
4496 # ifdef EXPERIMENTAL_PIPE_CONNECT
4497 fl.pipe_connect_acceptable && pipeline_connect_sends());
4505 int i = fwrite(g->s, 1, g->ptr, smtp_out); i = i; /* compiler quietening */
4511 (void) string_from_gstring(g);
4512 while ((cr = Ustrchr(g->s, '\r')) != NULL) /* lose CRs */
4513 memmove(cr, cr + 1, (g->ptr--) - (cr - g->s));
4514 debug_printf("SMTP>> %s", g->s);
4516 fl.helo_seen = TRUE;
4518 /* Reset the protocol and the state, abandoning any previous message. */
4520 (sender_host_address ? protocols : protocols_local)
4522 ? pextend + (sender_host_authenticated ? pauthed : 0)
4524 + (tls_in.active.sock >= 0 ? pcrpted : 0)
4526 cancel_cutthrough_connection(TRUE, US"sent EHLO response");
4527 smtp_reset(reset_point);
4529 break; /* HELO/EHLO */
4532 /* The MAIL command requires an address as an operand. All we do
4533 here is to parse it for syntactic correctness. The form "<>" is
4534 a special case which converts into an empty string. The start/end
4535 pointers in the original are not used further for this address, as
4536 it is the canonical extracted address which is all that is kept. */
4540 smtp_mailcmd_count++; /* Count for limit and ratelimit */
4541 was_rej_mail = TRUE; /* Reset if accepted */
4542 env_mail_type_t * mail_args; /* Sanity check & validate args */
4544 if (fl.helo_required && !fl.helo_seen)
4546 smtp_printf("503 HELO or EHLO required\r\n", FALSE);
4547 log_write(0, LOG_MAIN|LOG_REJECT, "rejected MAIL from %s: no "
4548 "HELO/EHLO given", host_and_ident(FALSE));
4554 done = synprot_error(L_smtp_protocol_error, 503, NULL,
4555 US"sender already given");
4559 if (!*smtp_cmd_data)
4561 done = synprot_error(L_smtp_protocol_error, 501, NULL,
4562 US"MAIL must have an address operand");
4566 /* Check to see if the limit for messages per connection would be
4567 exceeded by accepting further messages. */
4569 if (smtp_accept_max_per_connection > 0 &&
4570 smtp_mailcmd_count > smtp_accept_max_per_connection)
4572 smtp_printf("421 too many messages in this connection\r\n", FALSE);
4573 log_write(0, LOG_MAIN|LOG_REJECT, "rejected MAIL command %s: too many "
4574 "messages in one connection", host_and_ident(TRUE));
4578 /* Reset for start of message - even if this is going to fail, we
4579 obviously need to throw away any previous data. */
4581 cancel_cutthrough_connection(TRUE, US"MAIL received");
4582 smtp_reset(reset_point);
4584 sender_data = recipient_data = NULL;
4586 /* Loop, checking for ESMTP additions to the MAIL FROM command. */
4588 if (fl.esmtp) for(;;)
4590 uschar *name, *value, *end;
4591 unsigned long int size;
4592 BOOL arg_error = FALSE;
4594 if (!extract_option(&name, &value)) break;
4596 for (mail_args = env_mail_type_list;
4597 mail_args->value != ENV_MAIL_OPT_NULL;
4600 if (strcmpic(name, mail_args->name) == 0)
4602 if (mail_args->need_value && strcmpic(value, US"") == 0)
4605 switch(mail_args->value)
4607 /* Handle SIZE= by reading the value. We don't do the check till later,
4608 in order to be able to log the sender address on failure. */
4609 case ENV_MAIL_OPT_SIZE:
4610 if (((size = Ustrtoul(value, &end, 10)), *end == 0))
4612 if ((size == ULONG_MAX && errno == ERANGE) || size > INT_MAX)
4614 message_size = (int)size;
4620 /* If this session was initiated with EHLO and accept_8bitmime is set,
4621 Exim will have indicated that it supports the BODY=8BITMIME option. In
4622 fact, it does not support this according to the RFCs, in that it does not
4623 take any special action for forwarding messages containing 8-bit
4624 characters. That is why accept_8bitmime is not the default setting, but
4625 some sites want the action that is provided. We recognize both "8BITMIME"
4626 and "7BIT" as body types, but take no action. */
4627 case ENV_MAIL_OPT_BODY:
4628 if (accept_8bitmime) {
4629 if (strcmpic(value, US"8BITMIME") == 0)
4631 else if (strcmpic(value, US"7BIT") == 0)
4636 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4637 US"invalid data for BODY");
4640 DEBUG(D_receive) debug_printf("8BITMIME: %d\n", body_8bitmime);
4646 /* Handle the two DSN options, but only if configured to do so (which
4647 will have caused "DSN" to be given in the EHLO response). The code itself
4648 is included only if configured in at build time. */
4650 case ENV_MAIL_OPT_RET:
4651 if (fl.dsn_advertised)
4653 /* Check if RET has already been set */
4656 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4657 US"RET can be specified once only");
4660 dsn_ret = strcmpic(value, US"HDRS") == 0
4662 : strcmpic(value, US"FULL") == 0
4665 DEBUG(D_receive) debug_printf("DSN_RET: %d\n", dsn_ret);
4666 /* Check for invalid invalid value, and exit with error */
4669 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4670 US"Value for RET is invalid");
4675 case ENV_MAIL_OPT_ENVID:
4676 if (fl.dsn_advertised)
4678 /* Check if the dsn envid has been already set */
4681 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4682 US"ENVID can be specified once only");
4685 dsn_envid = string_copy(value);
4686 DEBUG(D_receive) debug_printf("DSN_ENVID: %s\n", dsn_envid);
4690 /* Handle the AUTH extension. If the value given is not "<>" and either
4691 the ACL says "yes" or there is no ACL but the sending host is
4692 authenticated, we set it up as the authenticated sender. However, if the
4693 authenticator set a condition to be tested, we ignore AUTH on MAIL unless
4694 the condition is met. The value of AUTH is an xtext, which means that +,
4695 = and cntrl chars are coded in hex; however "<>" is unaffected by this
4697 case ENV_MAIL_OPT_AUTH:
4698 if (Ustrcmp(value, "<>") != 0)
4703 if (auth_xtextdecode(value, &authenticated_sender) < 0)
4705 /* Put back terminator overrides for error message */
4708 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4709 US"invalid data for AUTH");
4712 if (!acl_smtp_mailauth)
4714 ignore_msg = US"client not authenticated";
4715 rc = sender_host_authenticated ? OK : FAIL;
4719 ignore_msg = US"rejected by ACL";
4720 rc = acl_check(ACL_WHERE_MAILAUTH, NULL, acl_smtp_mailauth,
4721 &user_msg, &log_msg);
4727 if (authenticated_by == NULL ||
4728 authenticated_by->mail_auth_condition == NULL ||
4729 expand_check_condition(authenticated_by->mail_auth_condition,
4730 authenticated_by->name, US"authenticator"))
4731 break; /* Accept the AUTH */
4733 ignore_msg = US"server_mail_auth_condition failed";
4734 if (authenticated_id != NULL)
4735 ignore_msg = string_sprintf("%s: authenticated ID=\"%s\"",
4736 ignore_msg, authenticated_id);
4741 authenticated_sender = NULL;
4742 log_write(0, LOG_MAIN, "ignoring AUTH=%s from %s (%s)",
4743 value, host_and_ident(TRUE), ignore_msg);
4746 /* Should only get DEFER or ERROR here. Put back terminator
4747 overrides for error message */
4752 (void)smtp_handle_acl_fail(ACL_WHERE_MAILAUTH, rc, user_msg,
4759 #ifndef DISABLE_PRDR
4760 case ENV_MAIL_OPT_PRDR:
4762 prdr_requested = TRUE;
4767 case ENV_MAIL_OPT_UTF8:
4768 if (!fl.smtputf8_advertised)
4770 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4771 US"SMTPUTF8 used when not advertised");
4775 DEBUG(D_receive) debug_printf("smtputf8 requested\n");
4776 message_smtputf8 = allow_utf8_domains = TRUE;
4777 if (Ustrncmp(received_protocol, US"utf8", 4) != 0)
4779 int old_pool = store_pool;
4780 store_pool = POOL_PERM;
4781 received_protocol = string_sprintf("utf8%s", received_protocol);
4782 store_pool = old_pool;
4787 #if defined(SUPPORT_TLS) && defined(EXPERIMENTAL_REQUIRETLS)
4788 case ENV_MAIL_OPT_REQTLS:
4792 if (!fl.requiretls_advertised)
4794 done = synprot_error(L_smtp_syntax_error, 555, NULL,
4795 US"unadvertised MAIL option: REQUIRETLS");
4799 DEBUG(D_receive) debug_printf("requiretls requested\n");
4800 tls_requiretls = REQUIRETLS_MSG;
4802 r = string_copy_malloc(received_protocol);
4803 if ((t = Ustrrchr(r, 's'))) *t = 'S';
4804 received_protocol = r;
4809 /* No valid option. Stick back the terminator characters and break
4810 the loop. Do the name-terminator second as extract_option sets
4811 value==name when it found no equal-sign.
4812 An error for a malformed address will occur. */
4813 case ENV_MAIL_OPT_NULL:
4821 /* Break out of for loop if switch() had bad argument or
4822 when start of the email address is reached */
4823 if (arg_error) break;
4826 #if defined(SUPPORT_TLS) && defined(EXPERIMENTAL_REQUIRETLS)
4827 if (tls_requiretls & REQUIRETLS_MSG)
4829 /* Ensure headers-only bounces whether a RET option was given or not. */
4831 DEBUG(D_receive) if (dsn_ret == dsn_ret_full)
4832 debug_printf("requiretls override: dsn_ret_full -> dsn_ret_hdrs\n");
4833 dsn_ret = dsn_ret_hdrs;
4837 /* If we have passed the threshold for rate limiting, apply the current
4838 delay, and update it for next time, provided this is a limited host. */
4840 if (smtp_mailcmd_count > smtp_rlm_threshold &&
4841 verify_check_host(&smtp_ratelimit_hosts) == OK)
4843 DEBUG(D_receive) debug_printf("rate limit MAIL: delay %.3g sec\n",
4844 smtp_delay_mail/1000.0);
4845 millisleep((int)smtp_delay_mail);
4846 smtp_delay_mail *= smtp_rlm_factor;
4847 if (smtp_delay_mail > (double)smtp_rlm_limit)
4848 smtp_delay_mail = (double)smtp_rlm_limit;
4851 /* Now extract the address, first applying any SMTP-time rewriting. The
4852 TRUE flag allows "<>" as a sender address. */
4854 raw_sender = rewrite_existflags & rewrite_smtp
4855 ? rewrite_one(smtp_cmd_data, rewrite_smtp, NULL, FALSE, US"",
4856 global_rewrite_rules)
4860 parse_extract_address(raw_sender, &errmess, &start, &end, &sender_domain,
4865 done = synprot_error(L_smtp_syntax_error, 501, smtp_cmd_data, errmess);
4869 sender_address = raw_sender;
4871 /* If there is a configured size limit for mail, check that this message
4872 doesn't exceed it. The check is postponed to this point so that the sender
4875 if (thismessage_size_limit > 0 && message_size > thismessage_size_limit)
4877 smtp_printf("552 Message size exceeds maximum permitted\r\n", FALSE);
4878 log_write(L_size_reject,
4879 LOG_MAIN|LOG_REJECT, "rejected MAIL FROM:<%s> %s: "
4880 "message too big: size%s=%d max=%d",
4882 host_and_ident(TRUE),
4883 (message_size == INT_MAX)? ">" : "",
4885 thismessage_size_limit);
4886 sender_address = NULL;
4890 /* Check there is enough space on the disk unless configured not to.
4891 When smtp_check_spool_space is set, the check is for thismessage_size_limit
4892 plus the current message - i.e. we accept the message only if it won't
4893 reduce the space below the threshold. Add 5000 to the size to allow for
4894 overheads such as the Received: line and storing of recipients, etc.
4895 By putting the check here, even when SIZE is not given, it allow VRFY
4896 and EXPN etc. to be used when space is short. */
4898 if (!receive_check_fs(
4899 (smtp_check_spool_space && message_size >= 0)?
4900 message_size + 5000 : 0))
4902 smtp_printf("452 Space shortage, please try later\r\n", FALSE);
4903 sender_address = NULL;
4907 /* If sender_address is unqualified, reject it, unless this is a locally
4908 generated message, or the sending host or net is permitted to send
4909 unqualified addresses - typically local machines behaving as MUAs -
4910 in which case just qualify the address. The flag is set above at the start
4911 of the SMTP connection. */
4913 if (!sender_domain && *sender_address)
4914 if (f.allow_unqualified_sender)
4916 sender_domain = Ustrlen(sender_address) + 1;
4917 sender_address = rewrite_address_qualify(sender_address, FALSE);
4918 DEBUG(D_receive) debug_printf("unqualified address %s accepted\n",
4923 smtp_printf("501 %s: sender address must contain a domain\r\n", FALSE,
4925 log_write(L_smtp_syntax_error,
4926 LOG_MAIN|LOG_REJECT,
4927 "unqualified sender rejected: <%s> %s%s",
4929 host_and_ident(TRUE),
4931 sender_address = NULL;
4935 /* Apply an ACL check if one is defined, before responding. Afterwards,
4936 when pipelining is not advertised, do another sync check in case the ACL
4937 delayed and the client started sending in the meantime. */
4941 rc = acl_check(ACL_WHERE_MAIL, NULL, acl_smtp_mail, &user_msg, &log_msg);
4942 if (rc == OK && !f.smtp_in_pipelining_advertised && !check_sync())
4948 if (rc == OK || rc == DISCARD)
4950 BOOL more = pipeline_response();
4953 smtp_printf("%s%s%s", more, US"250 OK",
4954 #ifndef DISABLE_PRDR
4955 prdr_requested ? US", PRDR Requested" : US"",
4962 #ifndef DISABLE_PRDR
4964 user_msg = string_sprintf("%s%s", user_msg, US", PRDR Requested");
4966 smtp_user_msg(US"250", user_msg);
4968 smtp_delay_rcpt = smtp_rlr_base;
4969 f.recipients_discarded = (rc == DISCARD);
4970 was_rej_mail = FALSE;
4974 done = smtp_handle_acl_fail(ACL_WHERE_MAIL, rc, user_msg, log_msg);
4975 sender_address = NULL;
4980 /* The RCPT command requires an address as an operand. There may be any
4981 number of RCPT commands, specifying multiple recipients. We build them all
4982 into a data structure. The start/end values given by parse_extract_address
4983 are not used, as we keep only the extracted address. */
4988 was_rcpt = fl.rcpt_in_progress = TRUE;
4990 /* There must be a sender address; if the sender was rejected and
4991 pipelining was advertised, we assume the client was pipelining, and do not
4992 count this as a protocol error. Reset was_rej_mail so that further RCPTs
4993 get the same treatment. */
4995 if (sender_address == NULL)
4997 if (f.smtp_in_pipelining_advertised && last_was_rej_mail)
4999 smtp_printf("503 sender not yet given\r\n", FALSE);
5000 was_rej_mail = TRUE;
5004 done = synprot_error(L_smtp_protocol_error, 503, NULL,
5005 US"sender not yet given");
5006 was_rcpt = FALSE; /* Not a valid RCPT */
5012 /* Check for an operand */
5014 if (smtp_cmd_data[0] == 0)
5016 done = synprot_error(L_smtp_syntax_error, 501, NULL,
5017 US"RCPT must have an address operand");
5022 /* Set the DSN flags orcpt and dsn_flags from the session*/
5026 if (fl.esmtp) for(;;)
5028 uschar *name, *value;
5030 if (!extract_option(&name, &value))
5033 if (fl.dsn_advertised && strcmpic(name, US"ORCPT") == 0)
5035 /* Check whether orcpt has been already set */
5038 done = synprot_error(L_smtp_syntax_error, 501, NULL,
5039 US"ORCPT can be specified once only");
5042 orcpt = string_copy(value);
5043 DEBUG(D_receive) debug_printf("DSN orcpt: %s\n", orcpt);
5046 else if (fl.dsn_advertised && strcmpic(name, US"NOTIFY") == 0)
5048 /* Check if the notify flags have been already set */
5051 done = synprot_error(L_smtp_syntax_error, 501, NULL,
5052 US"NOTIFY can be specified once only");
5055 if (strcmpic(value, US"NEVER") == 0)
5056 dsn_flags |= rf_notify_never;
5063 while (*pp != 0 && *pp != ',') pp++;
5064 if (*pp == ',') *pp++ = 0;
5065 if (strcmpic(p, US"SUCCESS") == 0)
5067 DEBUG(D_receive) debug_printf("DSN: Setting notify success\n");
5068 dsn_flags |= rf_notify_success;
5070 else if (strcmpic(p, US"FAILURE") == 0)
5072 DEBUG(D_receive) debug_printf("DSN: Setting notify failure\n");
5073 dsn_flags |= rf_notify_failure;
5075 else if (strcmpic(p, US"DELAY") == 0)
5077 DEBUG(D_receive) debug_printf("DSN: Setting notify delay\n");
5078 dsn_flags |= rf_notify_delay;
5082 /* Catch any strange values */
5083 done = synprot_error(L_smtp_syntax_error, 501, NULL,
5084 US"Invalid value for NOTIFY parameter");
5089 DEBUG(D_receive) debug_printf("DSN Flags: %x\n", dsn_flags);
5093 /* Unknown option. Stick back the terminator characters and break
5094 the loop. An error for a malformed address will occur. */
5098 DEBUG(D_receive) debug_printf("Invalid RCPT option: %s : %s\n", name, value);
5105 /* Apply SMTP rewriting then extract the working address. Don't allow "<>"
5106 as a recipient address */
5108 recipient = rewrite_existflags & rewrite_smtp
5109 ? rewrite_one(smtp_cmd_data, rewrite_smtp, NULL, FALSE, US"",
5110 global_rewrite_rules)
5113 if (!(recipient = parse_extract_address(recipient, &errmess, &start, &end,
5114 &recipient_domain, FALSE)))
5116 done = synprot_error(L_smtp_syntax_error, 501, smtp_cmd_data, errmess);
5121 /* If the recipient address is unqualified, reject it, unless this is a
5122 locally generated message. However, unqualified addresses are permitted
5123 from a configured list of hosts and nets - typically when behaving as
5124 MUAs rather than MTAs. Sad that SMTP is used for both types of traffic,
5125 really. The flag is set at the start of the SMTP connection.
5127 RFC 1123 talks about supporting "the reserved mailbox postmaster"; I always
5128 assumed this meant "reserved local part", but the revision of RFC 821 and
5129 friends now makes it absolutely clear that it means *mailbox*. Consequently
5130 we must always qualify this address, regardless. */
5132 if (!recipient_domain)
5133 if (!(recipient_domain = qualify_recipient(&recipient, smtp_cmd_data,
5140 /* Check maximum allowed */
5142 if (rcpt_count > recipients_max && recipients_max > 0)
5144 if (recipients_max_reject)
5147 smtp_printf("552 too many recipients\r\n", FALSE);
5149 log_write(0, LOG_MAIN|LOG_REJECT, "too many recipients: message "
5150 "rejected: sender=<%s> %s", sender_address, host_and_ident(TRUE));
5155 smtp_printf("452 too many recipients\r\n", FALSE);
5157 log_write(0, LOG_MAIN|LOG_REJECT, "too many recipients: excess "
5158 "temporarily rejected: sender=<%s> %s", sender_address,
5159 host_and_ident(TRUE));
5166 /* If we have passed the threshold for rate limiting, apply the current
5167 delay, and update it for next time, provided this is a limited host. */
5169 if (rcpt_count > smtp_rlr_threshold &&
5170 verify_check_host(&smtp_ratelimit_hosts) == OK)
5172 DEBUG(D_receive) debug_printf("rate limit RCPT: delay %.3g sec\n",
5173 smtp_delay_rcpt/1000.0);
5174 millisleep((int)smtp_delay_rcpt);
5175 smtp_delay_rcpt *= smtp_rlr_factor;
5176 if (smtp_delay_rcpt > (double)smtp_rlr_limit)
5177 smtp_delay_rcpt = (double)smtp_rlr_limit;
5180 /* If the MAIL ACL discarded all the recipients, we bypass ACL checking
5181 for them. Otherwise, check the access control list for this recipient. As
5182 there may be a delay in this, re-check for a synchronization error
5183 afterwards, unless pipelining was advertised. */
5185 if (f.recipients_discarded)
5188 if ( (rc = acl_check(ACL_WHERE_RCPT, recipient, acl_smtp_rcpt, &user_msg,
5190 && !f.smtp_in_pipelining_advertised && !check_sync())
5193 /* The ACL was happy */
5197 BOOL more = pipeline_response();
5200 smtp_user_msg(US"250", user_msg);
5202 smtp_printf("250 Accepted\r\n", more);
5203 receive_add_recipient(recipient, -1);
5205 /* Set the dsn flags in the recipients_list */
5206 recipients_list[recipients_count-1].orcpt = orcpt;
5207 recipients_list[recipients_count-1].dsn_flags = dsn_flags;
5209 DEBUG(D_receive) debug_printf("DSN: orcpt: %s flags: %d\n",
5210 recipients_list[recipients_count-1].orcpt,
5211 recipients_list[recipients_count-1].dsn_flags);
5214 /* The recipient was discarded */
5216 else if (rc == DISCARD)
5219 smtp_user_msg(US"250", user_msg);
5221 smtp_printf("250 Accepted\r\n", FALSE);
5224 log_write(0, LOG_MAIN|LOG_REJECT, "%s F=<%s> RCPT %s: "
5225 "discarded by %s ACL%s%s", host_and_ident(TRUE),
5226 sender_address_unrewritten? sender_address_unrewritten : sender_address,
5227 smtp_cmd_argument, f.recipients_discarded? "MAIL" : "RCPT",
5228 log_msg ? US": " : US"", log_msg ? log_msg : US"");
5231 /* Either the ACL failed the address, or it was deferred. */
5235 if (rc == FAIL) rcpt_fail_count++; else rcpt_defer_count++;
5236 done = smtp_handle_acl_fail(ACL_WHERE_RCPT, rc, user_msg, log_msg);
5241 /* The DATA command is legal only if it follows successful MAIL FROM
5242 and RCPT TO commands. However, if pipelining is advertised, a bad DATA is
5243 not counted as a protocol error if it follows RCPT (which must have been
5244 rejected if there are no recipients.) This function is complete when a
5245 valid DATA command is encountered.
5247 Note concerning the code used: RFC 2821 says this:
5249 - If there was no MAIL, or no RCPT, command, or all such commands
5250 were rejected, the server MAY return a "command out of sequence"
5251 (503) or "no valid recipients" (554) reply in response to the
5254 The example in the pipelining RFC 2920 uses 554, but I use 503 here
5255 because it is the same whether pipelining is in use or not.
5257 If all the RCPT commands that precede DATA provoked the same error message
5258 (often indicating some kind of system error), it is helpful to include it
5259 with the DATA rejection (an idea suggested by Tony Finch). */
5266 if (chunking_state != CHUNKING_OFFERED)
5268 done = synprot_error(L_smtp_protocol_error, 503, NULL,
5269 US"BDAT command used when CHUNKING not advertised");
5273 /* grab size, endmarker */
5275 if (sscanf(CS smtp_cmd_data, "%u %n", &chunking_datasize, &n) < 1)
5277 done = synprot_error(L_smtp_protocol_error, 501, NULL,
5278 US"missing size for BDAT command");
5281 chunking_state = strcmpic(smtp_cmd_data+n, US"LAST") == 0
5282 ? CHUNKING_LAST : CHUNKING_ACTIVE;
5283 chunking_data_left = chunking_datasize;
5284 DEBUG(D_receive) debug_printf("chunking state %d, %d bytes\n",
5285 (int)chunking_state, chunking_data_left);
5287 /* push the current receive_* function on the "stack", and
5288 replace them by bdat_getc(), which in turn will use the lwr_receive_*
5289 functions to do the dirty work. */
5290 lwr_receive_getc = receive_getc;
5291 lwr_receive_getbuf = receive_getbuf;
5292 lwr_receive_ungetc = receive_ungetc;
5294 receive_getc = bdat_getc;
5295 receive_ungetc = bdat_ungetc;
5306 DATA_BDAT: /* Common code for DATA and BDAT */
5307 #ifdef EXPERIMENTAL_PIPE_CONNECT
5308 fl.pipe_connect_acceptable = FALSE;
5310 if (!discarded && recipients_count <= 0)
5312 if (fl.rcpt_smtp_response_same && rcpt_smtp_response != NULL)
5314 uschar *code = US"503";
5315 int len = Ustrlen(rcpt_smtp_response);
5316 smtp_respond(code, 3, FALSE, US"All RCPT commands were rejected with "
5318 /* Responses from smtp_printf() will have \r\n on the end */
5319 if (len > 2 && rcpt_smtp_response[len-2] == '\r')
5320 rcpt_smtp_response[len-2] = 0;
5321 smtp_respond(code, 3, FALSE, rcpt_smtp_response);
5323 if (f.smtp_in_pipelining_advertised && last_was_rcpt)
5324 smtp_printf("503 Valid RCPT command must precede %s\r\n", FALSE,
5325 smtp_names[smtp_connection_had[smtp_ch_index-1]]);
5327 done = synprot_error(L_smtp_protocol_error, 503, NULL,
5328 smtp_connection_had[smtp_ch_index-1] == SCH_DATA
5329 ? US"valid RCPT command must precede DATA"
5330 : US"valid RCPT command must precede BDAT");
5332 if (chunking_state > CHUNKING_OFFERED)
5337 if (toomany && recipients_max_reject)
5339 sender_address = NULL; /* This will allow a new MAIL without RSET */
5340 sender_address_unrewritten = NULL;
5341 smtp_printf("554 Too many recipients\r\n", FALSE);
5345 if (chunking_state > CHUNKING_OFFERED)
5346 rc = OK; /* No predata ACL or go-ahead output for BDAT */
5349 /* If there is an ACL, re-check the synchronization afterwards, since the
5350 ACL may have delayed. To handle cutthrough delivery enforce a dummy call
5351 to get the DATA command sent. */
5353 if (acl_smtp_predata == NULL && cutthrough.cctx.sock < 0)
5357 uschar * acl = acl_smtp_predata ? acl_smtp_predata : US"accept";
5358 f.enable_dollar_recipients = TRUE;
5359 rc = acl_check(ACL_WHERE_PREDATA, NULL, acl, &user_msg,
5361 f.enable_dollar_recipients = FALSE;
5362 if (rc == OK && !check_sync())
5366 { /* Either the ACL failed the address, or it was deferred. */
5367 done = smtp_handle_acl_fail(ACL_WHERE_PREDATA, rc, user_msg, log_msg);
5373 smtp_user_msg(US"354", user_msg);
5376 "354 Enter message, ending with \".\" on a line by itself\r\n", FALSE);
5380 if (smtp_in) /* all ACKs needed to ramp window up for bulk data */
5381 (void) setsockopt(fileno(smtp_in), IPPROTO_TCP, TCP_QUICKACK,
5382 US &on, sizeof(on));
5385 message_ended = END_NOTENDED; /* Indicate in middle of data */
5396 if (!(address = parse_extract_address(smtp_cmd_data, &errmess,
5397 &start, &end, &recipient_domain, FALSE)))
5399 smtp_printf("501 %s\r\n", FALSE, errmess);
5403 if (!recipient_domain)
5404 if (!(recipient_domain = qualify_recipient(&address, smtp_cmd_data,
5408 if ((rc = acl_check(ACL_WHERE_VRFY, address, acl_smtp_vrfy,
5409 &user_msg, &log_msg)) != OK)
5410 done = smtp_handle_acl_fail(ACL_WHERE_VRFY, rc, user_msg, log_msg);
5414 address_item * addr = deliver_make_addr(address, FALSE);
5416 switch(verify_address(addr, NULL, vopt_is_recipient | vopt_qualify, -1,
5417 -1, -1, NULL, NULL, NULL))
5420 s = string_sprintf("250 <%s> is deliverable", address);
5424 s = (addr->user_message != NULL)?
5425 string_sprintf("451 <%s> %s", address, addr->user_message) :
5426 string_sprintf("451 Cannot resolve <%s> at this time", address);
5430 s = (addr->user_message != NULL)?
5431 string_sprintf("550 <%s> %s", address, addr->user_message) :
5432 string_sprintf("550 <%s> is not deliverable", address);
5433 log_write(0, LOG_MAIN, "VRFY failed for %s %s",
5434 smtp_cmd_argument, host_and_ident(TRUE));
5438 smtp_printf("%s\r\n", FALSE, s);
5446 rc = acl_check(ACL_WHERE_EXPN, NULL, acl_smtp_expn, &user_msg, &log_msg);
5448 done = smtp_handle_acl_fail(ACL_WHERE_EXPN, rc, user_msg, log_msg);
5451 BOOL save_log_testing_mode = f.log_testing_mode;
5452 f.address_test_mode = f.log_testing_mode = TRUE;
5453 (void) verify_address(deliver_make_addr(smtp_cmd_data, FALSE),
5454 smtp_out, vopt_is_recipient | vopt_qualify | vopt_expn, -1, -1, -1,
5456 f.address_test_mode = FALSE;
5457 f.log_testing_mode = save_log_testing_mode; /* true for -bh */
5466 if (!fl.tls_advertised)
5468 done = synprot_error(L_smtp_protocol_error, 503, NULL,
5469 US"STARTTLS command used when not advertised");
5473 /* Apply an ACL check if one is defined */
5475 if ( acl_smtp_starttls
5476 && (rc = acl_check(ACL_WHERE_STARTTLS, NULL, acl_smtp_starttls,
5477 &user_msg, &log_msg)) != OK
5480 done = smtp_handle_acl_fail(ACL_WHERE_STARTTLS, rc, user_msg, log_msg);
5484 /* RFC 2487 is not clear on when this command may be sent, though it
5485 does state that all information previously obtained from the client
5486 must be discarded if a TLS session is started. It seems reasonable to
5487 do an implied RSET when STARTTLS is received. */
5489 incomplete_transaction_log(US"STARTTLS");
5490 cancel_cutthrough_connection(TRUE, US"STARTTLS received");
5491 smtp_reset(reset_point);
5493 cmd_list[CMD_LIST_STARTTLS].is_mail_cmd = FALSE;
5495 /* There's an attack where more data is read in past the STARTTLS command
5496 before TLS is negotiated, then assumed to be part of the secure session
5497 when used afterwards; we use segregated input buffers, so are not
5498 vulnerable, but we want to note when it happens and, for sheer paranoia,
5499 ensure that the buffer is "wiped".
5500 Pipelining sync checks will normally have protected us too, unless disabled
5501 by configuration. */
5503 if (receive_smtp_buffered())
5506 debug_printf("Non-empty input buffer after STARTTLS; naive attack?\n");
5507 if (tls_in.active.sock < 0)
5508 smtp_inend = smtp_inptr = smtp_inbuffer;
5509 /* and if TLS is already active, tls_server_start() should fail */
5512 /* There is nothing we value in the input buffer and if TLS is successfully
5513 negotiated, we won't use this buffer again; if TLS fails, we'll just read
5514 fresh content into it. The buffer contains arbitrary content from an
5515 untrusted remote source; eg: NOOP <shellcode>\r\nSTARTTLS\r\n
5516 It seems safest to just wipe away the content rather than leave it as a
5517 target to jump to. */
5519 memset(smtp_inbuffer, 0, IN_BUFFER_SIZE);
5521 /* Attempt to start up a TLS session, and if successful, discard all
5522 knowledge that was obtained previously. At least, that's what the RFC says,
5523 and that's what happens by default. However, in order to work round YAEB,
5524 there is an option to remember the esmtp state. Sigh.
5526 We must allow for an extra EHLO command and an extra AUTH command after
5527 STARTTLS that don't add to the nonmail command count. */
5530 if ((rc = tls_server_start(tls_require_ciphers, &s)) == OK)
5532 if (!tls_remember_esmtp)
5533 fl.helo_seen = fl.esmtp = fl.auth_advertised = f.smtp_in_pipelining_advertised = FALSE;
5534 cmd_list[CMD_LIST_EHLO].is_mail_cmd = TRUE;
5535 cmd_list[CMD_LIST_AUTH].is_mail_cmd = TRUE;
5536 cmd_list[CMD_LIST_TLS_AUTH].is_mail_cmd = TRUE;
5537 if (sender_helo_name)
5539 store_free(sender_helo_name);
5540 sender_helo_name = NULL;
5541 host_build_sender_fullhost(); /* Rebuild */
5542 set_process_info("handling incoming TLS connection from %s",
5543 host_and_ident(FALSE));
5546 (sender_host_address ? protocols : protocols_local)
5548 ? pextend + (sender_host_authenticated ? pauthed : 0)
5550 + (tls_in.active.sock >= 0 ? pcrpted : 0)
5553 sender_host_auth_pubname = sender_host_authenticated = NULL;
5554 authenticated_id = NULL;
5555 sync_cmd_limit = NON_SYNC_CMD_NON_PIPELINING;
5556 DEBUG(D_tls) debug_printf("TLS active\n");
5557 break; /* Successful STARTTLS */
5560 (void) smtp_log_tls_fail(s);
5562 /* Some local configuration problem was discovered before actually trying
5563 to do a TLS handshake; give a temporary error. */
5567 smtp_printf("454 TLS currently unavailable\r\n", FALSE);
5571 /* Hard failure. Reject everything except QUIT or closed connection. One
5572 cause for failure is a nested STARTTLS, in which case tls_in.active remains
5573 set, but we must still reject all incoming commands. Another is a handshake
5574 failure - and there may some encrypted data still in the pipe to us, which we
5575 see as garbage commands. */
5577 DEBUG(D_tls) debug_printf("TLS failed to start\n");
5578 while (done <= 0) switch(smtp_read_command(FALSE, GETC_BUFFER_UNLIMITED))
5581 log_write(L_smtp_connection, LOG_MAIN, "%s closed by EOF",
5582 smtp_get_connection_info());
5583 smtp_notquit_exit(US"tls-failed", NULL, NULL);
5587 /* It is perhaps arguable as to which exit ACL should be called here,
5588 but as it is probably a situation that almost never arises, it
5589 probably doesn't matter. We choose to call the real QUIT ACL, which in
5590 some sense is perhaps "right". */
5595 && ((rc = acl_check(ACL_WHERE_QUIT, NULL, acl_smtp_quit, &user_msg,
5596 &log_msg)) == ERROR))
5597 log_write(0, LOG_MAIN|LOG_PANIC, "ACL for QUIT returned ERROR: %s",
5600 smtp_respond(US"221", 3, TRUE, user_msg);
5602 smtp_printf("221 %s closing connection\r\n", FALSE, smtp_active_hostname);
5603 log_write(L_smtp_connection, LOG_MAIN, "%s closed by QUIT",
5604 smtp_get_connection_info());
5609 smtp_printf("554 Security failure\r\n", FALSE);
5612 tls_close(NULL, TLS_SHUTDOWN_NOWAIT);
5617 /* The ACL for QUIT is provided for gathering statistical information or
5618 similar; it does not affect the response code, but it can supply a custom
5622 smtp_quit_handler(&user_msg, &log_msg);
5628 smtp_rset_handler();
5629 cancel_cutthrough_connection(TRUE, US"RSET received");
5630 smtp_reset(reset_point);
5637 smtp_printf("250 OK\r\n", FALSE);
5641 /* Show ETRN/EXPN/VRFY if there's an ACL for checking hosts; if actually
5642 used, a check will be done for permitted hosts. Show STARTTLS only if not
5643 already in a TLS session and if it would be advertised in the EHLO
5648 smtp_printf("214-Commands supported:\r\n", TRUE);
5652 Ustrcat(buffer, " AUTH");
5654 if (tls_in.active.sock < 0 &&
5655 verify_check_host(&tls_advertise_hosts) != FAIL)
5656 Ustrcat(buffer, " STARTTLS");
5658 Ustrcat(buffer, " HELO EHLO MAIL RCPT DATA BDAT");
5659 Ustrcat(buffer, " NOOP QUIT RSET HELP");
5660 if (acl_smtp_etrn != NULL) Ustrcat(buffer, " ETRN");
5661 if (acl_smtp_expn != NULL) Ustrcat(buffer, " EXPN");
5662 if (acl_smtp_vrfy != NULL) Ustrcat(buffer, " VRFY");
5663 smtp_printf("214%s\r\n", FALSE, buffer);
5669 incomplete_transaction_log(US"connection lost");
5670 smtp_notquit_exit(US"connection-lost", US"421",
5671 US"%s lost input connection", smtp_active_hostname);
5673 /* Don't log by default unless in the middle of a message, as some mailers
5674 just drop the call rather than sending QUIT, and it clutters up the logs.
5677 if (sender_address || recipients_count > 0)
5678 log_write(L_lost_incoming_connection, LOG_MAIN,
5679 "unexpected %s while reading SMTP command from %s%s%s D=%s",
5680 f.sender_host_unknown ? "EOF" : "disconnection",
5681 f.tcp_in_fastopen_logged
5684 ? f.tcp_in_fastopen_data ? US"TFO* " : US"TFO "
5686 host_and_ident(FALSE), smtp_read_error,
5687 string_timesince(&smtp_connection_start)
5691 log_write(L_smtp_connection, LOG_MAIN, "%s %slost%s D=%s",
5692 smtp_get_connection_info(),
5693 f.tcp_in_fastopen && !f.tcp_in_fastopen_logged ? US"TFO " : US"",
5695 string_timesince(&smtp_connection_start)
5706 done = synprot_error(L_smtp_protocol_error, 503, NULL,
5707 US"ETRN is not permitted inside a transaction");
5711 log_write(L_etrn, LOG_MAIN, "ETRN %s received from %s", smtp_cmd_argument,
5712 host_and_ident(FALSE));
5714 if ((rc = acl_check(ACL_WHERE_ETRN, NULL, acl_smtp_etrn,
5715 &user_msg, &log_msg)) != OK)
5717 done = smtp_handle_acl_fail(ACL_WHERE_ETRN, rc, user_msg, log_msg);
5721 /* Compute the serialization key for this command. */
5723 etrn_serialize_key = string_sprintf("etrn-%s\n", smtp_cmd_data);
5725 /* If a command has been specified for running as a result of ETRN, we
5726 permit any argument to ETRN. If not, only the # standard form is permitted,
5727 since that is strictly the only kind of ETRN that can be implemented
5728 according to the RFC. */
5730 if (smtp_etrn_command)
5734 etrn_command = smtp_etrn_command;
5735 deliver_domain = smtp_cmd_data;
5736 rc = transport_set_up_command(&argv, smtp_etrn_command, TRUE, 0, NULL,
5737 US"ETRN processing", &error);
5738 deliver_domain = NULL;
5741 log_write(0, LOG_MAIN|LOG_PANIC, "failed to set up ETRN command: %s",
5743 smtp_printf("458 Internal failure\r\n", FALSE);
5748 /* Else set up to call Exim with the -R option. */
5752 if (*smtp_cmd_data++ != '#')
5754 done = synprot_error(L_smtp_syntax_error, 501, NULL,
5755 US"argument must begin with #");
5758 etrn_command = US"exim -R";
5759 argv = CUSS child_exec_exim(CEE_RETURN_ARGV, TRUE, NULL, TRUE,
5760 *queue_name ? 4 : 2,
5761 US"-R", smtp_cmd_data,
5762 US"-MCG", queue_name);
5765 /* If we are host-testing, don't actually do anything. */
5771 debug_printf("ETRN command is: %s\n", etrn_command);
5772 debug_printf("ETRN command execution skipped\n");
5774 if (user_msg == NULL) smtp_printf("250 OK\r\n", FALSE);
5775 else smtp_user_msg(US"250", user_msg);
5780 /* If ETRN queue runs are to be serialized, check the database to
5781 ensure one isn't already running. */
5783 if (smtp_etrn_serialize && !enq_start(etrn_serialize_key, 1))
5785 smtp_printf("458 Already processing %s\r\n", FALSE, smtp_cmd_data);
5789 /* Fork a child process and run the command. We don't want to have to
5790 wait for the process at any point, so set SIGCHLD to SIG_IGN before
5791 forking. It should be set that way anyway for external incoming SMTP,
5792 but we save and restore to be tidy. If serialization is required, we
5793 actually run the command in yet another process, so we can wait for it
5794 to complete and then remove the serialization lock. */
5796 oldsignal = signal(SIGCHLD, SIG_IGN);
5798 if ((pid = fork()) == 0)
5800 smtp_input = FALSE; /* This process is not associated with the */
5801 (void)fclose(smtp_in); /* SMTP call any more. */
5802 (void)fclose(smtp_out);
5804 signal(SIGCHLD, SIG_DFL); /* Want to catch child */
5806 /* If not serializing, do the exec right away. Otherwise, fork down
5807 into another process. */
5809 if (!smtp_etrn_serialize || (pid = fork()) == 0)
5811 DEBUG(D_exec) debug_print_argv(argv);
5812 exim_nullstd(); /* Ensure std{in,out,err} exist */
5813 execv(CS argv[0], (char *const *)argv);
5814 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "exec of \"%s\" (ETRN) failed: %s",
5815 etrn_command, strerror(errno));
5816 _exit(EXIT_FAILURE); /* paranoia */
5819 /* Obey this if smtp_serialize and the 2nd fork yielded non-zero. That
5820 is, we are in the first subprocess, after forking again. All we can do
5821 for a failing fork is to log it. Otherwise, wait for the 2nd process to
5822 complete, before removing the serialization. */
5825 log_write(0, LOG_MAIN|LOG_PANIC, "2nd fork for serialized ETRN "
5826 "failed: %s", strerror(errno));
5830 DEBUG(D_any) debug_printf("waiting for serialized ETRN process %d\n",
5832 (void)wait(&status);
5833 DEBUG(D_any) debug_printf("serialized ETRN process %d ended\n",
5837 enq_end(etrn_serialize_key);
5838 _exit(EXIT_SUCCESS);
5841 /* Back in the top level SMTP process. Check that we started a subprocess
5842 and restore the signal state. */
5846 log_write(0, LOG_MAIN|LOG_PANIC, "fork of process for ETRN failed: %s",
5848 smtp_printf("458 Unable to fork process\r\n", FALSE);
5849 if (smtp_etrn_serialize) enq_end(etrn_serialize_key);
5853 if (user_msg == NULL) smtp_printf("250 OK\r\n", FALSE);
5854 else smtp_user_msg(US"250", user_msg);
5857 signal(SIGCHLD, oldsignal);
5862 done = synprot_error(L_smtp_syntax_error, 501, NULL,
5863 US"unexpected argument data");
5867 /* This currently happens only for NULLs, but could be extended. */
5870 done = synprot_error(L_smtp_syntax_error, 0, NULL, /* Just logs */
5871 US"NUL character(s) present (shown as '?')");
5872 smtp_printf("501 NUL characters are not allowed in SMTP commands\r\n",
5879 if (smtp_inend >= smtp_inbuffer + IN_BUFFER_SIZE)
5880 smtp_inend = smtp_inbuffer + IN_BUFFER_SIZE - 1;
5881 c = smtp_inend - smtp_inptr;
5882 if (c > 150) c = 150; /* limit logged amount */
5884 incomplete_transaction_log(US"sync failure");
5885 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP protocol synchronization error "
5886 "(next input sent too soon: pipelining was%s advertised): "
5887 "rejected \"%s\" %s next input=\"%s\"",
5888 f.smtp_in_pipelining_advertised ? "" : " not",
5889 smtp_cmd_buffer, host_and_ident(TRUE),
5890 string_printing(smtp_inptr));
5891 smtp_notquit_exit(US"synchronization-error", US"554",
5892 US"SMTP synchronization error");
5893 done = 1; /* Pretend eof - drops connection */
5897 case TOO_MANY_NONMAIL_CMD:
5898 s = smtp_cmd_buffer;
5899 while (*s != 0 && !isspace(*s)) s++;
5900 incomplete_transaction_log(US"too many non-mail commands");
5901 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
5902 "nonmail commands (last was \"%.*s\")", host_and_ident(FALSE),
5903 (int)(s - smtp_cmd_buffer), smtp_cmd_buffer);
5904 smtp_notquit_exit(US"bad-commands", US"554", US"Too many nonmail commands");
5905 done = 1; /* Pretend eof - drops connection */
5908 #ifdef SUPPORT_PROXY
5909 case PROXY_FAIL_IGNORE_CMD:
5910 smtp_printf("503 Command refused, required Proxy negotiation failed\r\n", FALSE);
5915 if (unknown_command_count++ >= smtp_max_unknown_commands)
5917 log_write(L_smtp_syntax_error, LOG_MAIN,
5918 "SMTP syntax error in \"%s\" %s %s",
5919 string_printing(smtp_cmd_buffer), host_and_ident(TRUE),
5920 US"unrecognized command");
5921 incomplete_transaction_log(US"unrecognized command");
5922 smtp_notquit_exit(US"bad-commands", US"500",
5923 US"Too many unrecognized commands");
5925 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
5926 "unrecognized commands (last was \"%s\")", host_and_ident(FALSE),
5927 string_printing(smtp_cmd_buffer));
5930 done = synprot_error(L_smtp_syntax_error, 500, NULL,
5931 US"unrecognized command");
5935 /* This label is used by goto's inside loops that want to break out to
5936 the end of the command-processing loop. */
5939 last_was_rej_mail = was_rej_mail; /* Remember some last commands for */
5940 last_was_rcpt = was_rcpt; /* protocol error handling */
5944 return done - 2; /* Convert yield values */
5950 authres_smtpauth(gstring * g)
5952 if (!sender_host_authenticated)
5955 g = string_append(g, 2, US";\n\tauth=pass (", sender_host_auth_pubname);
5957 if (Ustrcmp(sender_host_auth_pubname, "tls") != 0)
5958 g = string_append(g, 2, US") smtp.auth=", authenticated_id);
5959 else if (authenticated_id)
5960 g = string_append(g, 2, US") x509.auth=", authenticated_id);
5962 g = string_catn(g, US") reason=x509.auth", 17);
5964 if (authenticated_sender)
5965 g = string_append(g, 2, US" smtp.mailfrom=", authenticated_sender);
5973 /* End of smtp_in.c */