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 /* No transaction in progress */
439 || !LOGGING(smtp_incomplete_transaction))
442 /* Build list of recipients for logging */
444 if (recipients_count > 0)
446 raw_recipients = store_get(recipients_count * sizeof(uschar *));
447 for (int i = 0; i < recipients_count; i++)
448 raw_recipients[i] = recipients_list[i].address;
449 raw_recipients_count = recipients_count;
452 log_write(L_smtp_incomplete_transaction, LOG_MAIN|LOG_SENDER|LOG_RECIPIENTS,
453 "%s incomplete transaction (%s)", host_and_ident(TRUE), what);
460 smtp_command_timeout_exit(void)
462 log_write(L_lost_incoming_connection,
463 LOG_MAIN, "SMTP command timeout on%s connection from %s",
464 tls_in.active.sock >= 0 ? " TLS" : "", host_and_ident(FALSE));
465 if (smtp_batched_input)
466 moan_smtp_batch(NULL, "421 SMTP command timeout"); /* Does not return */
467 smtp_notquit_exit(US"command-timeout", US"421",
468 US"%s: SMTP command timeout - closing connection",
469 smtp_active_hostname);
470 exim_exit(EXIT_FAILURE, US"receiving");
474 smtp_command_sigterm_exit(void)
476 log_write(0, LOG_MAIN, "%s closed after SIGTERM", smtp_get_connection_info());
477 if (smtp_batched_input)
478 moan_smtp_batch(NULL, "421 SIGTERM received"); /* Does not return */
479 smtp_notquit_exit(US"signal-exit", US"421",
480 US"%s: Service not available - closing connection", smtp_active_hostname);
481 exim_exit(EXIT_FAILURE, US"receiving");
485 smtp_data_timeout_exit(void)
487 log_write(L_lost_incoming_connection,
488 LOG_MAIN, "SMTP data timeout (message abandoned) on connection from %s F=<%s>",
489 sender_fullhost ? sender_fullhost : US"local process", sender_address);
490 receive_bomb_out(US"data-timeout", US"SMTP incoming data timeout");
491 /* Does not return */
495 smtp_data_sigint_exit(void)
497 log_write(0, LOG_MAIN, "%s closed after %s",
498 smtp_get_connection_info(), had_data_sigint == SIGTERM ? "SIGTERM":"SIGINT");
499 receive_bomb_out(US"signal-exit",
500 US"Service not available - SIGTERM or SIGINT received");
501 /* Does not return */
506 /* Refill the buffer, and notify DKIM verification code.
507 Return false for error or EOF.
511 smtp_refill(unsigned lim)
514 if (!smtp_out) return FALSE;
516 if (smtp_receive_timeout > 0) ALARM(smtp_receive_timeout);
518 /* Limit amount read, so non-message data is not fed to DKIM.
519 Take care to not touch the safety NUL at the end of the buffer. */
521 rc = read(fileno(smtp_in), smtp_inbuffer, MIN(IN_BUFFER_SIZE-1, lim));
523 if (smtp_receive_timeout > 0) ALARM_CLR(0);
526 /* Must put the error text in fixed store, because this might be during
527 header reading, where it releases unused store above the header. */
530 if (had_command_timeout) /* set by signal handler */
531 smtp_command_timeout_exit(); /* does not return */
532 if (had_command_sigterm)
533 smtp_command_sigterm_exit();
534 if (had_data_timeout)
535 smtp_data_timeout_exit();
537 smtp_data_sigint_exit();
539 smtp_had_error = save_errno;
540 smtp_read_error = string_copy_malloc(
541 string_sprintf(" (error: %s)", strerror(save_errno)));
548 dkim_exim_verify_feed(smtp_inbuffer, rc);
550 smtp_inend = smtp_inbuffer + rc;
551 smtp_inptr = smtp_inbuffer;
555 /*************************************************
556 * SMTP version of getc() *
557 *************************************************/
559 /* This gets the next byte from the SMTP input buffer. If the buffer is empty,
560 it flushes the output, and refills the buffer, with a timeout. The signal
561 handler is set appropriately by the calling function. This function is not used
562 after a connection has negotiated itself into an TLS/SSL state.
564 Arguments: lim Maximum amount to read/buffer
565 Returns: the next character or EOF
569 smtp_getc(unsigned lim)
571 if (smtp_inptr >= smtp_inend)
572 if (!smtp_refill(lim))
574 return *smtp_inptr++;
578 smtp_getbuf(unsigned * len)
583 if (smtp_inptr >= smtp_inend)
584 if (!smtp_refill(*len))
585 { *len = 0; return NULL; }
587 if ((size = smtp_inend - smtp_inptr) > *len) size = *len;
598 int n = smtp_inend - smtp_inptr;
600 dkim_exim_verify_feed(smtp_inptr, n);
605 /* Get a byte from the smtp input, in CHUNKING mode. Handle ack of the
606 previous BDAT chunk and getting new ones when we run out. Uses the
607 underlying smtp_getc or tls_getc both for that and for getting the
608 (buffered) data byte. EOD signals (an expected) no further data.
609 ERR signals a protocol error, and EOF a closed input stream.
611 Called from read_bdat_smtp() in receive.c for the message body, but also
612 by the headers read loop in receive_msg(); manipulates chunking_state
613 to handle the BDAT command/response.
614 Placed here due to the correlation with the above smtp_getc(), which it wraps,
615 and also by the need to do smtp command/response handling.
617 Arguments: lim (ignored)
618 Returns: the next character or ERR, EOD or EOF
622 bdat_getc(unsigned lim)
624 uschar * user_msg = NULL;
633 if (chunking_data_left > 0)
634 return lwr_receive_getc(chunking_data_left--);
636 receive_getc = lwr_receive_getc;
637 receive_getbuf = lwr_receive_getbuf;
638 receive_ungetc = lwr_receive_ungetc;
640 dkim_save = dkim_collect_input;
641 dkim_collect_input = 0;
644 /* Unless PIPELINING was offered, there should be no next command
645 until after we ack that chunk */
647 if (!f.smtp_in_pipelining_advertised && !check_sync())
649 unsigned n = smtp_inend - smtp_inptr;
652 incomplete_transaction_log(US"sync failure");
653 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP protocol synchronization error "
654 "(next input sent too soon: pipelining was not advertised): "
655 "rejected \"%s\" %s next input=\"%s\"%s",
656 smtp_cmd_buffer, host_and_ident(TRUE),
657 string_printing(string_copyn(smtp_inptr, n)),
658 smtp_inend - smtp_inptr > n ? "..." : "");
659 (void) synprot_error(L_smtp_protocol_error, 554, NULL,
660 US"SMTP synchronization error");
661 goto repeat_until_rset;
664 /* If not the last, ack the received chunk. The last response is delayed
665 until after the data ACL decides on it */
667 if (chunking_state == CHUNKING_LAST)
670 dkim_exim_verify_feed(NULL, 0); /* notify EOD */
675 smtp_printf("250 %u byte chunk received\r\n", FALSE, chunking_datasize);
676 chunking_state = CHUNKING_OFFERED;
677 DEBUG(D_receive) debug_printf("chunking state %d\n", (int)chunking_state);
679 /* Expect another BDAT cmd from input. RFC 3030 says nothing about
680 QUIT, RSET or NOOP but handling them seems obvious */
683 switch(smtp_read_command(TRUE, 1))
686 (void) synprot_error(L_smtp_protocol_error, 503, NULL,
687 US"only BDAT permissible after non-LAST BDAT");
690 switch(smtp_read_command(TRUE, 1))
692 case QUIT_CMD: smtp_quit_handler(&user_msg, &log_msg); /*FALLTHROUGH */
693 case EOF_CMD: return EOF;
694 case RSET_CMD: smtp_rset_handler(); return ERR;
695 default: if (synprot_error(L_smtp_protocol_error, 503, NULL,
696 US"only RSET accepted now") > 0)
698 goto repeat_until_rset;
702 smtp_quit_handler(&user_msg, &log_msg);
713 smtp_printf("250 OK\r\n", FALSE);
720 if (sscanf(CS smtp_cmd_data, "%u %n", &chunking_datasize, &n) < 1)
722 (void) synprot_error(L_smtp_protocol_error, 501, NULL,
723 US"missing size for BDAT command");
726 chunking_state = strcmpic(smtp_cmd_data+n, US"LAST") == 0
727 ? CHUNKING_LAST : CHUNKING_ACTIVE;
728 chunking_data_left = chunking_datasize;
729 DEBUG(D_receive) debug_printf("chunking state %d, %d bytes\n",
730 (int)chunking_state, chunking_data_left);
732 if (chunking_datasize == 0)
733 if (chunking_state == CHUNKING_LAST)
737 (void) synprot_error(L_smtp_protocol_error, 504, NULL,
738 US"zero size for BDAT command");
739 goto repeat_until_rset;
742 receive_getc = bdat_getc;
743 receive_getbuf = bdat_getbuf; /* r~getbuf is never actually used */
744 receive_ungetc = bdat_ungetc;
746 dkim_collect_input = dkim_save;
748 break; /* to top of main loop */
755 bdat_getbuf(unsigned * len)
759 if (chunking_data_left <= 0)
760 { *len = 0; return NULL; }
762 if (*len > chunking_data_left) *len = chunking_data_left;
763 buf = lwr_receive_getbuf(len); /* Either smtp_getbuf or tls_getbuf */
764 chunking_data_left -= *len;
769 bdat_flush_data(void)
771 while (chunking_data_left)
773 unsigned n = chunking_data_left;
774 if (!bdat_getbuf(&n)) break;
777 receive_getc = lwr_receive_getc;
778 receive_getbuf = lwr_receive_getbuf;
779 receive_ungetc = lwr_receive_ungetc;
781 if (chunking_state != CHUNKING_LAST)
783 chunking_state = CHUNKING_OFFERED;
784 DEBUG(D_receive) debug_printf("chunking state %d\n", (int)chunking_state);
791 /*************************************************
792 * SMTP version of ungetc() *
793 *************************************************/
795 /* Puts a character back in the input buffer. Only ever
801 Returns: the character
815 chunking_data_left++;
816 return lwr_receive_ungetc(ch);
821 /*************************************************
822 * SMTP version of feof() *
823 *************************************************/
825 /* Tests for a previous EOF
828 Returns: non-zero if the eof flag is set
840 /*************************************************
841 * SMTP version of ferror() *
842 *************************************************/
844 /* Tests for a previous read error, and returns with errno
845 restored to what it was when the error was detected.
848 Returns: non-zero if the error flag is set
854 errno = smtp_had_error;
855 return smtp_had_error;
860 /*************************************************
861 * Test for characters in the SMTP buffer *
862 *************************************************/
864 /* Used at the end of a message
873 return smtp_inptr < smtp_inend;
878 /*************************************************
879 * Write formatted string to SMTP channel *
880 *************************************************/
882 /* This is a separate function so that we don't have to repeat everything for
883 TLS support or debugging. It is global so that the daemon and the
884 authentication functions can use it. It does not return any error indication,
885 because major problems such as dropped connections won't show up till an output
886 flush for non-TLS connections. The smtp_fflush() function is available for
887 checking that: for convenience, TLS output errors are remembered here so that
888 they are also picked up later by smtp_fflush().
892 more further data expected
893 ... optional arguments
899 smtp_printf(const char *format, BOOL more, ...)
904 smtp_vprintf(format, more, ap);
908 /* This is split off so that verify.c:respond_printf() can, in effect, call
909 smtp_printf(), bearing in mind that in C a vararg function can't directly
910 call another vararg function, only a function which accepts a va_list. */
913 smtp_vprintf(const char *format, BOOL more, va_list ap)
915 gstring gs = { .size = big_buffer_size, .ptr = 0, .s = big_buffer };
918 yield = !! string_vformat(&gs, FALSE, format, ap);
919 string_from_gstring(&gs);
923 void *reset_point = store_get(0);
924 uschar *msg_copy, *cr, *end;
925 msg_copy = string_copy(gs.s);
926 end = msg_copy + gs.ptr;
927 while ((cr = Ustrchr(msg_copy, '\r')) != NULL) /* lose CRs */
928 memmove(cr, cr + 1, (end--) - cr);
929 debug_printf("SMTP>> %s", msg_copy);
930 store_reset(reset_point);
935 log_write(0, LOG_MAIN|LOG_PANIC, "string too large in smtp_printf()");
936 smtp_closedown(US"Unexpected error");
937 exim_exit(EXIT_FAILURE, NULL);
940 /* If this is the first output for a (non-batch) RCPT command, see if all RCPTs
941 have had the same. Note: this code is also present in smtp_respond(). It would
942 be tidier to have it only in one place, but when it was added, it was easier to
943 do it that way, so as not to have to mess with the code for the RCPT command,
944 which sometimes uses smtp_printf() and sometimes smtp_respond(). */
946 if (fl.rcpt_in_progress)
948 if (rcpt_smtp_response == NULL)
949 rcpt_smtp_response = string_copy(big_buffer);
950 else if (fl.rcpt_smtp_response_same &&
951 Ustrcmp(rcpt_smtp_response, big_buffer) != 0)
952 fl.rcpt_smtp_response_same = FALSE;
953 fl.rcpt_in_progress = FALSE;
956 /* Now write the string */
959 if (tls_in.active.sock >= 0)
961 if (tls_write(NULL, gs.s, gs.ptr, more) < 0)
962 smtp_write_error = -1;
967 if (fprintf(smtp_out, "%s", gs.s) < 0) smtp_write_error = -1;
972 /*************************************************
973 * Flush SMTP out and check for error *
974 *************************************************/
976 /* This function isn't currently used within Exim (it detects errors when it
977 tries to read the next SMTP input), but is available for use in local_scan().
978 For non-TLS connections, it flushes the output and checks for errors. For
979 TLS-connections, it checks for a previously-detected TLS write error.
982 Returns: 0 for no error; -1 after an error
988 if (tls_in.active.sock < 0 && fflush(smtp_out) != 0) smtp_write_error = -1;
989 return smtp_write_error;
994 /*************************************************
995 * SMTP command read timeout *
996 *************************************************/
998 /* Signal handler for timing out incoming SMTP commands. This attempts to
1001 Argument: signal number (SIGALRM)
1006 command_timeout_handler(int sig)
1008 had_command_timeout = sig;
1013 /*************************************************
1014 * SIGTERM received *
1015 *************************************************/
1017 /* Signal handler for handling SIGTERM. Again, try to finish tidily.
1019 Argument: signal number (SIGTERM)
1024 command_sigterm_handler(int sig)
1026 had_command_sigterm = sig;
1032 #ifdef SUPPORT_PROXY
1033 /*************************************************
1034 * Restore socket timeout to previous value *
1035 *************************************************/
1036 /* If the previous value was successfully retrieved, restore
1037 it before returning control to the non-proxy routines
1039 Arguments: fd - File descriptor for input
1040 get_ok - Successfully retrieved previous values
1041 tvtmp - Time struct with previous values
1042 vslen - Length of time struct
1046 restore_socket_timeout(int fd, int get_ok, struct timeval * tvtmp, socklen_t vslen)
1049 (void) setsockopt(fd, SOL_SOCKET, SO_RCVTIMEO, CS tvtmp, vslen);
1052 /*************************************************
1053 * Check if host is required proxy host *
1054 *************************************************/
1055 /* The function determines if inbound host will be a regular smtp host
1056 or if it is configured that it must use Proxy Protocol. A local
1064 check_proxy_protocol_host()
1068 if ( sender_host_address
1069 && (rc = verify_check_this_host(CUSS &hosts_proxy, NULL, NULL,
1070 sender_host_address, NULL)) == OK)
1073 debug_printf("Detected proxy protocol configured host\n");
1074 proxy_session = TRUE;
1076 return proxy_session;
1080 /*************************************************
1081 * Read data until newline or end of buffer *
1082 *************************************************/
1083 /* While SMTP is server-speaks-first, TLS is client-speaks-first, so we can't
1084 read an entire buffer and assume there will be nothing past a proxy protocol
1085 header. Our approach normally is to use stdio, but again that relies upon
1086 "STARTTLS\r\n" and a server response before the client starts TLS handshake, or
1087 reading _nothing_ before client TLS handshake. So we don't want to use the
1088 usual buffering reads which may read enough to block TLS starting.
1090 So unfortunately we're down to "read one byte at a time, with a syscall each,
1091 and expect a little overhead", for all proxy-opened connections which are v1,
1092 just to handle the TLS-on-connect case. Since SSL functions wrap the
1093 underlying fd, we can't assume that we can feed them any already-read content.
1095 We need to know where to read to, the max capacity, and we'll read until we
1096 get a CR and one more character. Let the caller scream if it's CR+!LF.
1098 Return the amount read.
1102 swallow_until_crlf(int fd, uschar *base, int already, int capacity)
1104 uschar *to = base + already;
1110 /* For "PROXY UNKNOWN\r\n" we, at time of writing, expect to have read
1111 up through the \r; for the _normal_ case, we haven't yet seen the \r. */
1113 cr = memchr(base, '\r', already);
1116 if ((cr - base) < already - 1)
1118 /* \r and presumed \n already within what we have; probably not
1119 actually proxy protocol, but abort cleanly. */
1122 /* \r is last character read, just need one more. */
1126 while (capacity > 0)
1128 do { ret = recv(fd, to, 1, 0); } while (ret == -1 && errno == EINTR);
1140 /* reached end without having room for a final newline, abort */
1145 /*************************************************
1146 * Setup host for proxy protocol *
1147 *************************************************/
1148 /* The function configures the connection based on a header from the
1149 inbound host to use Proxy Protocol. The specification is very exact
1150 so exit with an error if do not find the exact required pieces. This
1151 includes an incorrect number of spaces separating args.
1154 Returns: Boolean success
1158 setup_proxy_protocol_host()
1170 struct { /* TCP/UDP over IPv4, len = 12 */
1176 struct { /* TCP/UDP over IPv6, len = 36 */
1177 uint8_t src_addr[16];
1178 uint8_t dst_addr[16];
1182 struct { /* AF_UNIX sockets, len = 216 */
1183 uschar src_addr[108];
1184 uschar dst_addr[108];
1190 /* Temp variables used in PPv2 address:port parsing */
1192 char tmpip[INET_ADDRSTRLEN];
1193 struct sockaddr_in tmpaddr;
1194 char tmpip6[INET6_ADDRSTRLEN];
1195 struct sockaddr_in6 tmpaddr6;
1197 /* We can't read "all data until end" because while SMTP is
1198 server-speaks-first, the TLS handshake is client-speaks-first, so for
1199 TLS-on-connect ports the proxy protocol header will usually be immediately
1200 followed by a TLS handshake, and with N TLS libraries, we can't reliably
1201 reinject data for reading by those. So instead we first read "enough to be
1202 safely read within the header, and figure out how much more to read".
1203 For v1 we will later read to the end-of-line, for v2 we will read based upon
1206 The v2 sig is 12 octets, and another 4 gets us the length, so we know how much
1207 data is needed total. For v1, where the line looks like:
1208 PROXY TCPn L3src L3dest SrcPort DestPort \r\n
1210 However, for v1 there's also `PROXY UNKNOWN\r\n` which is only 15 octets.
1211 We seem to support that. So, if we read 14 octets then we can tell if we're
1212 v2 or v1. If we're v1, we can continue reading as normal.
1214 If we're v2, we can't slurp up the entire header. We need the length in the
1215 15th & 16th octets, then to read everything after that.
1217 So to safely handle v1 and v2, with client-sent-first supported correctly,
1218 we have to do a minimum of 3 read calls, not 1. Eww.
1221 #define PROXY_INITIAL_READ 14
1222 #define PROXY_V2_HEADER_SIZE 16
1223 #if PROXY_INITIAL_READ > PROXY_V2_HEADER_SIZE
1224 # error Code bug in sizes of data to read for proxy usage
1229 int fd = fileno(smtp_in);
1230 const char v2sig[12] = "\x0D\x0A\x0D\x0A\x00\x0D\x0A\x51\x55\x49\x54\x0A";
1231 uschar * iptype; /* To display debug info */
1233 struct timeval tvtmp;
1234 socklen_t vslen = sizeof(struct timeval);
1237 /* Save current socket timeout values */
1238 get_ok = getsockopt(fd, SOL_SOCKET, SO_RCVTIMEO, CS &tvtmp, &vslen);
1240 /* Proxy Protocol host must send header within a short time
1241 (default 3 seconds) or it's considered invalid */
1242 tv.tv_sec = PROXY_NEGOTIATION_TIMEOUT_SEC;
1243 tv.tv_usec = PROXY_NEGOTIATION_TIMEOUT_USEC;
1244 if (setsockopt(fd, SOL_SOCKET, SO_RCVTIMEO, CS &tv, sizeof(tv)) < 0)
1249 /* The inbound host was declared to be a Proxy Protocol host, so
1250 don't do a PEEK into the data, actually slurp up enough to be
1251 "safe". Can't take it all because TLS-on-connect clients follow
1252 immediately with TLS handshake. */
1253 ret = recv(fd, &hdr, PROXY_INITIAL_READ, 0);
1255 while (ret == -1 && errno == EINTR);
1260 /* For v2, handle reading the length, and then the rest. */
1261 if ((ret == PROXY_INITIAL_READ) && (memcmp(&hdr.v2, v2sig, sizeof(v2sig)) == 0))
1266 /* First get the length fields. */
1269 retmore = recv(fd, (uschar*)&hdr + ret, PROXY_V2_HEADER_SIZE - PROXY_INITIAL_READ, 0);
1270 } while (retmore == -1 && errno == EINTR);
1275 ver = (hdr.v2.ver_cmd & 0xf0) >> 4;
1277 /* May 2014: haproxy combined the version and command into one byte to
1278 allow two full bytes for the length field in order to proxy SSL
1279 connections. SSL Proxy is not supported in this version of Exim, but
1280 must still separate values here. */
1284 DEBUG(D_receive) debug_printf("Invalid Proxy Protocol version: %d\n", ver);
1288 /* The v2 header will always be 16 bytes per the spec. */
1289 size = 16 + ntohs(hdr.v2.len);
1290 DEBUG(D_receive) debug_printf("Detected PROXYv2 header, size %d (limit %d)\n",
1291 size, (int)sizeof(hdr));
1293 /* We should now have 16 octets (PROXY_V2_HEADER_SIZE), and we know the total
1294 amount that we need. Double-check that the size is not unreasonable, then
1296 if (size > sizeof(hdr))
1298 DEBUG(D_receive) debug_printf("PROXYv2 header size unreasonably large; security attack?\n");
1306 retmore = recv(fd, (uschar*)&hdr + ret, size-ret, 0);
1307 } while (retmore == -1 && errno == EINTR);
1311 DEBUG(D_receive) debug_printf("PROXYv2: have %d/%d required octets\n", ret, size);
1312 } while (ret < size);
1314 } /* end scope for getting rest of data for v2 */
1316 /* At this point: if PROXYv2, we've read the exact size required for all data;
1317 if PROXYv1 then we've read "less than required for any valid line" and should
1320 if (ret >= 16 && memcmp(&hdr.v2, v2sig, 12) == 0)
1322 uint8_t cmd = (hdr.v2.ver_cmd & 0x0f);
1326 case 0x01: /* PROXY command */
1329 case 0x11: /* TCPv4 address type */
1331 tmpaddr.sin_addr.s_addr = hdr.v2.addr.ip4.src_addr;
1332 inet_ntop(AF_INET, &tmpaddr.sin_addr, CS &tmpip, sizeof(tmpip));
1333 if (!string_is_ip_address(US tmpip, NULL))
1335 DEBUG(D_receive) debug_printf("Invalid %s source IP\n", iptype);
1338 proxy_local_address = sender_host_address;
1339 sender_host_address = string_copy(US tmpip);
1340 tmpport = ntohs(hdr.v2.addr.ip4.src_port);
1341 proxy_local_port = sender_host_port;
1342 sender_host_port = tmpport;
1343 /* Save dest ip/port */
1344 tmpaddr.sin_addr.s_addr = hdr.v2.addr.ip4.dst_addr;
1345 inet_ntop(AF_INET, &tmpaddr.sin_addr, CS &tmpip, sizeof(tmpip));
1346 if (!string_is_ip_address(US tmpip, NULL))
1348 DEBUG(D_receive) debug_printf("Invalid %s dest port\n", iptype);
1351 proxy_external_address = string_copy(US tmpip);
1352 tmpport = ntohs(hdr.v2.addr.ip4.dst_port);
1353 proxy_external_port = tmpport;
1355 case 0x21: /* TCPv6 address type */
1357 memmove(tmpaddr6.sin6_addr.s6_addr, hdr.v2.addr.ip6.src_addr, 16);
1358 inet_ntop(AF_INET6, &tmpaddr6.sin6_addr, CS &tmpip6, sizeof(tmpip6));
1359 if (!string_is_ip_address(US tmpip6, NULL))
1361 DEBUG(D_receive) debug_printf("Invalid %s source IP\n", iptype);
1364 proxy_local_address = sender_host_address;
1365 sender_host_address = string_copy(US tmpip6);
1366 tmpport = ntohs(hdr.v2.addr.ip6.src_port);
1367 proxy_local_port = sender_host_port;
1368 sender_host_port = tmpport;
1369 /* Save dest ip/port */
1370 memmove(tmpaddr6.sin6_addr.s6_addr, hdr.v2.addr.ip6.dst_addr, 16);
1371 inet_ntop(AF_INET6, &tmpaddr6.sin6_addr, CS &tmpip6, sizeof(tmpip6));
1372 if (!string_is_ip_address(US tmpip6, NULL))
1374 DEBUG(D_receive) debug_printf("Invalid %s dest port\n", iptype);
1377 proxy_external_address = string_copy(US tmpip6);
1378 tmpport = ntohs(hdr.v2.addr.ip6.dst_port);
1379 proxy_external_port = tmpport;
1383 debug_printf("Unsupported PROXYv2 connection type: 0x%02x\n",
1387 /* Unsupported protocol, keep local connection address */
1389 case 0x00: /* LOCAL command */
1390 /* Keep local connection address for LOCAL */
1395 debug_printf("Unsupported PROXYv2 command: 0x%x\n", cmd);
1399 else if (ret >= 8 && memcmp(hdr.v1.line, "PROXY", 5) == 0)
1403 uschar *sp; /* Utility variables follow */
1408 /* get the rest of the line */
1409 r2 = swallow_until_crlf(fd, (uschar*)&hdr, ret, sizeof(hdr)-ret);
1414 p = string_copy(hdr.v1.line);
1415 end = memchr(p, '\r', ret - 1);
1417 if (!end || (end == (uschar*)&hdr + ret) || end[1] != '\n')
1419 DEBUG(D_receive) debug_printf("Partial or invalid PROXY header\n");
1422 *end = '\0'; /* Terminate the string */
1423 size = end + 2 - p; /* Skip header + CRLF */
1424 DEBUG(D_receive) debug_printf("Detected PROXYv1 header\n");
1425 DEBUG(D_receive) debug_printf("Bytes read not within PROXY header: %d\n", ret - size);
1426 /* Step through the string looking for the required fields. Ensure
1427 strict adherence to required formatting, exit for any error. */
1429 if (!isspace(*(p++)))
1431 DEBUG(D_receive) debug_printf("Missing space after PROXY command\n");
1434 if (!Ustrncmp(p, CCS"TCP4", 4))
1436 else if (!Ustrncmp(p,CCS"TCP6", 4))
1438 else if (!Ustrncmp(p,CCS"UNKNOWN", 7))
1440 iptype = US"Unknown";
1445 DEBUG(D_receive) debug_printf("Invalid TCP type\n");
1449 p += Ustrlen(iptype);
1450 if (!isspace(*(p++)))
1452 DEBUG(D_receive) debug_printf("Missing space after TCP4/6 command\n");
1455 /* Find the end of the arg */
1456 if ((sp = Ustrchr(p, ' ')) == NULL)
1459 debug_printf("Did not find proxied src %s\n", iptype);
1463 if(!string_is_ip_address(p, NULL))
1466 debug_printf("Proxied src arg is not an %s address\n", iptype);
1469 proxy_local_address = sender_host_address;
1470 sender_host_address = p;
1472 if ((sp = Ustrchr(p, ' ')) == NULL)
1475 debug_printf("Did not find proxy dest %s\n", iptype);
1479 if(!string_is_ip_address(p, NULL))
1482 debug_printf("Proxy dest arg is not an %s address\n", iptype);
1485 proxy_external_address = p;
1487 if ((sp = Ustrchr(p, ' ')) == NULL)
1489 DEBUG(D_receive) debug_printf("Did not find proxied src port\n");
1493 tmp_port = strtol(CCS p, &endc, 10);
1494 if (*endc || tmp_port == 0)
1497 debug_printf("Proxied src port '%s' not an integer\n", p);
1500 proxy_local_port = sender_host_port;
1501 sender_host_port = tmp_port;
1503 if ((sp = Ustrchr(p, '\0')) == NULL)
1505 DEBUG(D_receive) debug_printf("Did not find proxy dest port\n");
1508 tmp_port = strtol(CCS p, &endc, 10);
1509 if (*endc || tmp_port == 0)
1512 debug_printf("Proxy dest port '%s' not an integer\n", p);
1515 proxy_external_port = tmp_port;
1516 /* Already checked for /r /n above. Good V1 header received. */
1520 /* Wrong protocol */
1521 DEBUG(D_receive) debug_printf("Invalid proxy protocol version negotiation\n");
1522 (void) swallow_until_crlf(fd, (uschar*)&hdr, ret, sizeof(hdr)-ret);
1528 debug_printf("Valid %s sender from Proxy Protocol header\n", iptype);
1529 yield = proxy_session;
1531 /* Don't flush any potential buffer contents. Any input on proxyfail
1532 should cause a synchronization failure */
1535 restore_socket_timeout(fd, get_ok, &tvtmp, vslen);
1540 sender_host_name = NULL;
1541 (void) host_name_lookup();
1542 host_build_sender_fullhost();
1546 f.proxy_session_failed = TRUE;
1548 debug_printf("Failure to extract proxied host, only QUIT allowed\n");
1555 /*************************************************
1556 * Read one command line *
1557 *************************************************/
1559 /* Strictly, SMTP commands coming over the net are supposed to end with CRLF.
1560 There are sites that don't do this, and in any case internal SMTP probably
1561 should check only for LF. Consequently, we check here for LF only. The line
1562 ends up with [CR]LF removed from its end. If we get an overlong line, treat as
1563 an unknown command. The command is read into the global smtp_cmd_buffer so that
1564 it is available via $smtp_command.
1566 The character reading routine sets up a timeout for each block actually read
1567 from the input (which may contain more than one command). We set up a special
1568 signal handler that closes down the session on a timeout. Control does not
1569 return when it runs.
1572 check_sync if TRUE, check synchronization rules if global option is TRUE
1573 buffer_lim maximum to buffer in lower layer
1575 Returns: a code identifying the command (enumerated above)
1579 smtp_read_command(BOOL check_sync, unsigned buffer_lim)
1583 BOOL hadnull = FALSE;
1585 had_command_timeout = 0;
1586 os_non_restarting_signal(SIGALRM, command_timeout_handler);
1588 while ((c = (receive_getc)(buffer_lim)) != '\n' && c != EOF)
1590 if (ptr >= SMTP_CMD_BUFFER_SIZE)
1592 os_non_restarting_signal(SIGALRM, sigalrm_handler);
1600 smtp_cmd_buffer[ptr++] = c;
1603 receive_linecount++; /* For BSMTP errors */
1604 os_non_restarting_signal(SIGALRM, sigalrm_handler);
1606 /* If hit end of file, return pseudo EOF command. Whether we have a
1607 part-line already read doesn't matter, since this is an error state. */
1609 if (c == EOF) return EOF_CMD;
1611 /* Remove any CR and white space at the end of the line, and terminate the
1614 while (ptr > 0 && isspace(smtp_cmd_buffer[ptr-1])) ptr--;
1615 smtp_cmd_buffer[ptr] = 0;
1617 DEBUG(D_receive) debug_printf("SMTP<< %s\n", smtp_cmd_buffer);
1619 /* NULLs are not allowed in SMTP commands */
1621 if (hadnull) return BADCHAR_CMD;
1623 /* Scan command list and return identity, having set the data pointer
1624 to the start of the actual data characters. Check for SMTP synchronization
1627 for (smtp_cmd_list * p = cmd_list; p < cmd_list_end; p++)
1629 #ifdef SUPPORT_PROXY
1630 /* Only allow QUIT command if Proxy Protocol parsing failed */
1631 if (proxy_session && f.proxy_session_failed && p->cmd != QUIT_CMD)
1635 && strncmpic(smtp_cmd_buffer, US p->name, p->len) == 0
1636 && ( smtp_cmd_buffer[p->len-1] == ':' /* "mail from:" or "rcpt to:" */
1637 || smtp_cmd_buffer[p->len] == 0
1638 || smtp_cmd_buffer[p->len] == ' '
1641 if (smtp_inptr < smtp_inend && /* Outstanding input */
1642 p->cmd < sync_cmd_limit && /* Command should sync */
1643 check_sync && /* Local flag set */
1644 smtp_enforce_sync && /* Global flag set */
1645 sender_host_address != NULL && /* Not local input */
1646 !f.sender_host_notsocket) /* Really is a socket */
1649 /* The variables $smtp_command and $smtp_command_argument point into the
1650 unmodified input buffer. A copy of the latter is taken for actual
1651 processing, so that it can be chopped up into separate parts if necessary,
1652 for example, when processing a MAIL command options such as SIZE that can
1653 follow the sender address. */
1655 smtp_cmd_argument = smtp_cmd_buffer + p->len;
1656 while (isspace(*smtp_cmd_argument)) smtp_cmd_argument++;
1657 Ustrcpy(smtp_data_buffer, smtp_cmd_argument);
1658 smtp_cmd_data = smtp_data_buffer;
1660 /* Count non-mail commands from those hosts that are controlled in this
1661 way. The default is all hosts. We don't waste effort checking the list
1662 until we get a non-mail command, but then cache the result to save checking
1663 again. If there's a DEFER while checking the host, assume it's in the list.
1665 Note that one instance of RSET, EHLO/HELO, and STARTTLS is allowed at the
1666 start of each incoming message by fiddling with the value in the table. */
1668 if (!p->is_mail_cmd)
1670 if (count_nonmail == TRUE_UNSET) count_nonmail =
1671 verify_check_host(&smtp_accept_max_nonmail_hosts) != FAIL;
1672 if (count_nonmail && ++nonmail_command_count > smtp_accept_max_nonmail)
1673 return TOO_MANY_NONMAIL_CMD;
1676 /* If there is data for a command that does not expect it, generate the
1679 return (p->has_arg || *smtp_cmd_data == 0)? p->cmd : BADARG_CMD;
1683 #ifdef SUPPORT_PROXY
1684 /* Only allow QUIT command if Proxy Protocol parsing failed */
1685 if (proxy_session && f.proxy_session_failed)
1686 return PROXY_FAIL_IGNORE_CMD;
1689 /* Enforce synchronization for unknown commands */
1691 if ( smtp_inptr < smtp_inend /* Outstanding input */
1692 && check_sync /* Local flag set */
1693 && smtp_enforce_sync /* Global flag set */
1694 && sender_host_address /* Not local input */
1695 && !f.sender_host_notsocket) /* Really is a socket */
1703 /*************************************************
1704 * Forced closedown of call *
1705 *************************************************/
1707 /* This function is called from log.c when Exim is dying because of a serious
1708 disaster, and also from some other places. If an incoming non-batched SMTP
1709 channel is open, it swallows the rest of the incoming message if in the DATA
1710 phase, sends the reply string, and gives an error to all subsequent commands
1711 except QUIT. The existence of an SMTP call is detected by the non-NULLness of
1715 message SMTP reply string to send, excluding the code
1721 smtp_closedown(uschar *message)
1723 if (!smtp_in || smtp_batched_input) return;
1724 receive_swallow_smtp();
1725 smtp_printf("421 %s\r\n", FALSE, message);
1727 for (;;) switch(smtp_read_command(FALSE, GETC_BUFFER_UNLIMITED))
1733 smtp_printf("221 %s closing connection\r\n", FALSE, smtp_active_hostname);
1738 smtp_printf("250 Reset OK\r\n", FALSE);
1742 smtp_printf("421 %s\r\n", FALSE, message);
1750 /*************************************************
1751 * Set up connection info for logging *
1752 *************************************************/
1754 /* This function is called when logging information about an SMTP connection.
1755 It sets up appropriate source information, depending on the type of connection.
1756 If sender_fullhost is NULL, we are at a very early stage of the connection;
1757 just use the IP address.
1760 Returns: a string describing the connection
1764 smtp_get_connection_info(void)
1766 const uschar * hostname = sender_fullhost
1767 ? sender_fullhost : sender_host_address;
1770 return string_sprintf("SMTP connection from %s", hostname);
1772 if (f.sender_host_unknown || f.sender_host_notsocket)
1773 return string_sprintf("SMTP connection from %s", sender_ident);
1776 return string_sprintf("SMTP connection from %s (via inetd)", hostname);
1778 if (LOGGING(incoming_interface) && interface_address)
1779 return string_sprintf("SMTP connection from %s I=[%s]:%d", hostname,
1780 interface_address, interface_port);
1782 return string_sprintf("SMTP connection from %s", hostname);
1788 /* Append TLS-related information to a log line
1791 g String under construction: allocated string to extend, or NULL
1793 Returns: Allocated string or NULL
1796 s_tlslog(gstring * g)
1798 if (LOGGING(tls_cipher) && tls_in.cipher)
1799 g = string_append(g, 2, US" X=", tls_in.cipher);
1800 if (LOGGING(tls_certificate_verified) && tls_in.cipher)
1801 g = string_append(g, 2, US" CV=", tls_in.certificate_verified? "yes":"no");
1802 if (LOGGING(tls_peerdn) && tls_in.peerdn)
1803 g = string_append(g, 3, US" DN=\"", string_printing(tls_in.peerdn), US"\"");
1804 if (LOGGING(tls_sni) && tls_in.sni)
1805 g = string_append(g, 3, US" SNI=\"", string_printing(tls_in.sni), US"\"");
1810 /*************************************************
1811 * Log lack of MAIL if so configured *
1812 *************************************************/
1814 /* This function is called when an SMTP session ends. If the log selector
1815 smtp_no_mail is set, write a log line giving some details of what has happened
1816 in the SMTP session.
1823 smtp_log_no_mail(void)
1828 if (smtp_mailcmd_count > 0 || !LOGGING(smtp_no_mail))
1831 if (sender_host_authenticated)
1833 g = string_append(g, 2, US" A=", sender_host_authenticated);
1834 if (authenticated_id) g = string_append(g, 2, US":", authenticated_id);
1841 sep = smtp_connection_had[SMTP_HBUFF_SIZE-1] != SCH_NONE ? US" C=..." : US" C=";
1843 for (int i = smtp_ch_index; i < SMTP_HBUFF_SIZE; i++)
1844 if (smtp_connection_had[i] != SCH_NONE)
1846 g = string_append(g, 2, sep, smtp_names[smtp_connection_had[i]]);
1850 for (int i = 0; i < smtp_ch_index; i++)
1852 g = string_append(g, 2, sep, smtp_names[smtp_connection_had[i]]);
1856 if (!(s = string_from_gstring(g))) s = US"";
1858 log_write(0, LOG_MAIN, "no MAIL in %sSMTP connection from %s D=%s%s",
1859 f.tcp_in_fastopen ? f.tcp_in_fastopen_data ? US"TFO* " : US"TFO " : US"",
1860 host_and_ident(FALSE), string_timesince(&smtp_connection_start), s);
1864 /* Return list of recent smtp commands */
1869 gstring * list = NULL;
1872 for (int i = smtp_ch_index; i < SMTP_HBUFF_SIZE; i++)
1873 if (smtp_connection_had[i] != SCH_NONE)
1874 list = string_append_listele(list, ',', smtp_names[smtp_connection_had[i]]);
1876 for (int i = 0; i < smtp_ch_index; i++)
1877 list = string_append_listele(list, ',', smtp_names[smtp_connection_had[i]]);
1879 s = string_from_gstring(list);
1880 return s ? s : US"";
1886 /*************************************************
1887 * Check HELO line and set sender_helo_name *
1888 *************************************************/
1890 /* Check the format of a HELO line. The data for HELO/EHLO is supposed to be
1891 the domain name of the sending host, or an ip literal in square brackets. The
1892 argument is placed in sender_helo_name, which is in malloc store, because it
1893 must persist over multiple incoming messages. If helo_accept_junk is set, this
1894 host is permitted to send any old junk (needed for some broken hosts).
1895 Otherwise, helo_allow_chars can be used for rogue characters in general
1896 (typically people want to let in underscores).
1899 s the data portion of the line (already past any white space)
1901 Returns: TRUE or FALSE
1905 check_helo(uschar *s)
1908 uschar *end = s + Ustrlen(s);
1909 BOOL yield = fl.helo_accept_junk;
1911 /* Discard any previous helo name */
1913 if (sender_helo_name)
1915 store_free(sender_helo_name);
1916 sender_helo_name = NULL;
1919 /* Skip tests if junk is permitted. */
1923 /* Allow the new standard form for IPv6 address literals, namely,
1924 [IPv6:....], and because someone is bound to use it, allow an equivalent
1925 IPv4 form. Allow plain addresses as well. */
1932 if (strncmpic(s, US"[IPv6:", 6) == 0)
1933 yield = (string_is_ip_address(s+6, NULL) == 6);
1934 else if (strncmpic(s, US"[IPv4:", 6) == 0)
1935 yield = (string_is_ip_address(s+6, NULL) == 4);
1937 yield = (string_is_ip_address(s+1, NULL) != 0);
1942 /* Non-literals must be alpha, dot, hyphen, plus any non-valid chars
1943 that have been configured (usually underscore - sigh). */
1946 for (yield = TRUE; *s; s++)
1947 if (!isalnum(*s) && *s != '.' && *s != '-' &&
1948 Ustrchr(helo_allow_chars, *s) == NULL)
1954 /* Save argument if OK */
1956 if (yield) sender_helo_name = string_copy_malloc(start);
1964 /*************************************************
1965 * Extract SMTP command option *
1966 *************************************************/
1968 /* This function picks the next option setting off the end of smtp_cmd_data. It
1969 is called for MAIL FROM and RCPT TO commands, to pick off the optional ESMTP
1970 things that can appear there.
1973 name point this at the name
1974 value point this at the data string
1976 Returns: TRUE if found an option
1980 extract_option(uschar **name, uschar **value)
1983 uschar *v = smtp_cmd_data + Ustrlen(smtp_cmd_data) - 1;
1984 while (isspace(*v)) v--;
1986 while (v > smtp_cmd_data && *v != '=' && !isspace(*v))
1988 /* Take care to not stop at a space embedded in a quoted local-part */
1990 if (*v == '"') do v--; while (*v != '"' && v > smtp_cmd_data+1);
1997 while(isalpha(n[-1])) n--;
1998 /* RFC says SP, but TAB seen in wild and other major MTAs accept it */
1999 if (!isspace(n[-1])) return FALSE;
2005 if (v == smtp_cmd_data) return FALSE;
2017 /*************************************************
2018 * Reset for new message *
2019 *************************************************/
2021 /* This function is called whenever the SMTP session is reset from
2022 within either of the setup functions; also from the daemon loop.
2024 Argument: the stacking pool storage reset point
2029 smtp_reset(void *reset_point)
2031 recipients_list = NULL;
2032 rcpt_count = rcpt_defer_count = rcpt_fail_count =
2033 raw_recipients_count = recipients_count = recipients_list_max = 0;
2034 message_linecount = 0;
2036 acl_added_headers = NULL;
2037 acl_removed_headers = NULL;
2038 f.queue_only_policy = FALSE;
2039 rcpt_smtp_response = NULL;
2040 fl.rcpt_smtp_response_same = TRUE;
2041 fl.rcpt_in_progress = FALSE;
2042 f.deliver_freeze = FALSE; /* Can be set by ACL */
2043 freeze_tell = freeze_tell_config; /* Can be set by ACL */
2044 fake_response = OK; /* Can be set by ACL */
2045 #ifdef WITH_CONTENT_SCAN
2046 f.no_mbox_unspool = FALSE; /* Can be set by ACL */
2048 f.submission_mode = FALSE; /* Can be set by ACL */
2049 f.suppress_local_fixups = f.suppress_local_fixups_default; /* Can be set by ACL */
2050 f.active_local_from_check = local_from_check; /* Can be set by ACL */
2051 f.active_local_sender_retain = local_sender_retain; /* Can be set by ACL */
2052 sending_ip_address = NULL;
2053 return_path = sender_address = NULL;
2054 sender_data = NULL; /* Can be set by ACL */
2055 deliver_localpart_parent = deliver_localpart_orig = NULL;
2056 deliver_domain_parent = deliver_domain_orig = NULL;
2057 callout_address = NULL;
2058 submission_name = NULL; /* Can be set by ACL */
2059 raw_sender = NULL; /* After SMTP rewrite, before qualifying */
2060 sender_address_unrewritten = NULL; /* Set only after verify rewrite */
2061 sender_verified_list = NULL; /* No senders verified */
2062 memset(sender_address_cache, 0, sizeof(sender_address_cache));
2063 memset(sender_domain_cache, 0, sizeof(sender_domain_cache));
2065 authenticated_sender = NULL;
2066 #ifdef EXPERIMENTAL_BRIGHTMAIL
2068 bmi_verdicts = NULL;
2070 dnslist_domain = dnslist_matched = NULL;
2072 spf_header_comment = spf_received = spf_result = spf_smtp_comment = NULL;
2073 spf_result_guessed = FALSE;
2075 #ifndef DISABLE_DKIM
2076 dkim_cur_signer = dkim_signers =
2077 dkim_signing_domain = dkim_signing_selector = dkim_signatures = NULL;
2078 dkim_cur_signer = dkim_signers = dkim_signing_domain = dkim_signing_selector = NULL;
2079 f.dkim_disable_verify = FALSE;
2080 dkim_collect_input = 0;
2081 dkim_verify_overall = dkim_verify_status = dkim_verify_reason = NULL;
2082 dkim_key_length = 0;
2083 dkim_verify_signers = US"$dkim_signers";
2085 #ifdef EXPERIMENTAL_DMARC
2086 f.dmarc_has_been_checked = f.dmarc_disable_verify = f.dmarc_enable_forensic = FALSE;
2087 dmarc_domain_policy = dmarc_status = dmarc_status_text =
2088 dmarc_used_domain = NULL;
2090 #ifdef EXPERIMENTAL_ARC
2091 arc_state = arc_state_reason = NULL;
2095 deliver_host = deliver_host_address = NULL; /* Can be set by ACL */
2096 #ifndef DISABLE_PRDR
2097 prdr_requested = FALSE;
2100 message_smtputf8 = FALSE;
2102 body_linecount = body_zerocount = 0;
2104 sender_rate = sender_rate_limit = sender_rate_period = NULL;
2105 ratelimiters_mail = NULL; /* Updated by ratelimit ACL condition */
2106 /* Note that ratelimiters_conn persists across resets. */
2108 /* Reset message ACL variables */
2112 /* The message body variables use malloc store. They may be set if this is
2113 not the first message in an SMTP session and the previous message caused them
2114 to be referenced in an ACL. */
2118 store_free(message_body);
2119 message_body = NULL;
2122 if (message_body_end)
2124 store_free(message_body_end);
2125 message_body_end = NULL;
2128 /* Warning log messages are also saved in malloc store. They are saved to avoid
2129 repetition in the same message, but it seems right to repeat them for different
2132 while (acl_warn_logged)
2134 string_item *this = acl_warn_logged;
2135 acl_warn_logged = acl_warn_logged->next;
2138 store_reset(reset_point);
2145 /*************************************************
2146 * Initialize for incoming batched SMTP message *
2147 *************************************************/
2149 /* This function is called from smtp_setup_msg() in the case when
2150 smtp_batched_input is true. This happens when -bS is used to pass a whole batch
2151 of messages in one file with SMTP commands between them. All errors must be
2152 reported by sending a message, and only MAIL FROM, RCPT TO, and DATA are
2153 relevant. After an error on a sender, or an invalid recipient, the remainder
2154 of the message is skipped. The value of received_protocol is already set.
2157 Returns: > 0 message successfully started (reached DATA)
2158 = 0 QUIT read or end of file reached
2159 < 0 should not occur
2163 smtp_setup_batch_msg(void)
2166 void *reset_point = store_get(0);
2168 /* Save the line count at the start of each transaction - single commands
2169 like HELO and RSET count as whole transactions. */
2171 bsmtp_transaction_linecount = receive_linecount;
2173 if ((receive_feof)()) return 0; /* Treat EOF as QUIT */
2175 cancel_cutthrough_connection(TRUE, US"smtp_setup_batch_msg");
2176 smtp_reset(reset_point); /* Reset for start of message */
2178 /* Deal with SMTP commands. This loop is exited by setting done to a POSITIVE
2179 value. The values are 2 larger than the required yield of the function. */
2184 uschar *recipient = NULL;
2185 int start, end, sender_domain, recipient_domain;
2187 switch(smtp_read_command(FALSE, GETC_BUFFER_UNLIMITED))
2189 /* The HELO/EHLO commands set sender_address_helo if they have
2190 valid data; otherwise they are ignored, except that they do
2191 a reset of the state. */
2196 check_helo(smtp_cmd_data);
2200 cancel_cutthrough_connection(TRUE, US"RSET received");
2201 smtp_reset(reset_point);
2202 bsmtp_transaction_linecount = receive_linecount;
2206 /* The MAIL FROM command requires an address as an operand. All we
2207 do here is to parse it for syntactic correctness. The form "<>" is
2208 a special case which converts into an empty string. The start/end
2209 pointers in the original are not used further for this address, as
2210 it is the canonical extracted address which is all that is kept. */
2213 smtp_mailcmd_count++; /* Count for no-mail log */
2214 if (sender_address != NULL)
2215 /* The function moan_smtp_batch() does not return. */
2216 moan_smtp_batch(smtp_cmd_buffer, "503 Sender already given");
2218 if (smtp_cmd_data[0] == 0)
2219 /* The function moan_smtp_batch() does not return. */
2220 moan_smtp_batch(smtp_cmd_buffer, "501 MAIL FROM must have an address operand");
2222 /* Reset to start of message */
2224 cancel_cutthrough_connection(TRUE, US"MAIL received");
2225 smtp_reset(reset_point);
2227 /* Apply SMTP rewrite */
2229 raw_sender = ((rewrite_existflags & rewrite_smtp) != 0)?
2230 rewrite_one(smtp_cmd_data, rewrite_smtp|rewrite_smtp_sender, NULL, FALSE,
2231 US"", global_rewrite_rules) : smtp_cmd_data;
2233 /* Extract the address; the TRUE flag allows <> as valid */
2236 parse_extract_address(raw_sender, &errmess, &start, &end, &sender_domain,
2240 /* The function moan_smtp_batch() does not return. */
2241 moan_smtp_batch(smtp_cmd_buffer, "501 %s", errmess);
2243 sender_address = string_copy(raw_sender);
2245 /* Qualify unqualified sender addresses if permitted to do so. */
2248 && sender_address[0] != 0 && sender_address[0] != '@')
2249 if (f.allow_unqualified_sender)
2251 sender_address = rewrite_address_qualify(sender_address, FALSE);
2252 DEBUG(D_receive) debug_printf("unqualified address %s accepted "
2253 "and rewritten\n", raw_sender);
2255 /* The function moan_smtp_batch() does not return. */
2257 moan_smtp_batch(smtp_cmd_buffer, "501 sender address must contain "
2262 /* The RCPT TO command requires an address as an operand. All we do
2263 here is to parse it for syntactic correctness. There may be any number
2264 of RCPT TO commands, specifying multiple senders. We build them all into
2265 a data structure that is in argc/argv format. The start/end values
2266 given by parse_extract_address are not used, as we keep only the
2267 extracted address. */
2270 if (!sender_address)
2271 /* The function moan_smtp_batch() does not return. */
2272 moan_smtp_batch(smtp_cmd_buffer, "503 No sender yet given");
2274 if (smtp_cmd_data[0] == 0)
2275 /* The function moan_smtp_batch() does not return. */
2276 moan_smtp_batch(smtp_cmd_buffer,
2277 "501 RCPT TO must have an address operand");
2279 /* Check maximum number allowed */
2281 if (recipients_max > 0 && recipients_count + 1 > recipients_max)
2282 /* The function moan_smtp_batch() does not return. */
2283 moan_smtp_batch(smtp_cmd_buffer, "%s too many recipients",
2284 recipients_max_reject? "552": "452");
2286 /* Apply SMTP rewrite, then extract address. Don't allow "<>" as a
2287 recipient address */
2289 recipient = rewrite_existflags & rewrite_smtp
2290 ? rewrite_one(smtp_cmd_data, rewrite_smtp, NULL, FALSE, US"",
2291 global_rewrite_rules)
2294 recipient = parse_extract_address(recipient, &errmess, &start, &end,
2295 &recipient_domain, FALSE);
2298 /* The function moan_smtp_batch() does not return. */
2299 moan_smtp_batch(smtp_cmd_buffer, "501 %s", errmess);
2301 /* If the recipient address is unqualified, qualify it if permitted. Then
2302 add it to the list of recipients. */
2304 if (!recipient_domain)
2305 if (f.allow_unqualified_recipient)
2307 DEBUG(D_receive) debug_printf("unqualified address %s accepted\n",
2309 recipient = rewrite_address_qualify(recipient, TRUE);
2311 /* The function moan_smtp_batch() does not return. */
2313 moan_smtp_batch(smtp_cmd_buffer,
2314 "501 recipient address must contain a domain");
2316 receive_add_recipient(recipient, -1);
2320 /* The DATA command is legal only if it follows successful MAIL FROM
2321 and RCPT TO commands. This function is complete when a valid DATA
2322 command is encountered. */
2325 if (!sender_address || recipients_count <= 0)
2326 /* The function moan_smtp_batch() does not return. */
2327 if (!sender_address)
2328 moan_smtp_batch(smtp_cmd_buffer,
2329 "503 MAIL FROM:<sender> command must precede DATA");
2331 moan_smtp_batch(smtp_cmd_buffer,
2332 "503 RCPT TO:<recipient> must precede DATA");
2335 done = 3; /* DATA successfully achieved */
2336 message_ended = END_NOTENDED; /* Indicate in middle of message */
2341 /* The VRFY, EXPN, HELP, ETRN, and NOOP commands are ignored. */
2348 bsmtp_transaction_linecount = receive_linecount;
2359 /* The function moan_smtp_batch() does not return. */
2360 moan_smtp_batch(smtp_cmd_buffer, "501 Unexpected argument data");
2365 /* The function moan_smtp_batch() does not return. */
2366 moan_smtp_batch(smtp_cmd_buffer, "501 Unexpected NULL in SMTP command");
2371 /* The function moan_smtp_batch() does not return. */
2372 moan_smtp_batch(smtp_cmd_buffer, "500 Command unrecognized");
2377 return done - 2; /* Convert yield values */
2385 smtp_log_tls_fail(uschar * errstr)
2387 uschar * conn_info = smtp_get_connection_info();
2389 if (Ustrncmp(conn_info, US"SMTP ", 5) == 0) conn_info += 5;
2390 /* I'd like to get separated H= here, but too hard for now */
2392 log_write(0, LOG_MAIN, "TLS error on %s %s", conn_info, errstr);
2405 struct tcp_info tinfo;
2406 socklen_t len = sizeof(tinfo);
2408 if (getsockopt(fileno(smtp_out), IPPROTO_TCP, TCP_INFO, &tinfo, &len) == 0)
2409 #ifdef TCPI_OPT_SYN_DATA /* FreeBSD 11 does not seem to have this yet */
2410 if (tinfo.tcpi_options & TCPI_OPT_SYN_DATA)
2412 DEBUG(D_receive) debug_printf("TCP_FASTOPEN mode connection (ACKd data-on-SYN)\n");
2413 f.tcp_in_fastopen_data = f.tcp_in_fastopen = TRUE;
2417 if (tinfo.tcpi_state == TCP_SYN_RECV)
2419 DEBUG(D_receive) debug_printf("TCP_FASTOPEN mode connection (state TCP_SYN_RECV)\n");
2420 f.tcp_in_fastopen = TRUE;
2427 /*************************************************
2428 * Start an SMTP session *
2429 *************************************************/
2431 /* This function is called at the start of an SMTP session. Thereafter,
2432 smtp_setup_msg() is called to initiate each separate message. This
2433 function does host-specific testing, and outputs the banner line.
2436 Returns: FALSE if the session can not continue; something has
2437 gone wrong, or the connection to the host is blocked
2441 smtp_start_session(void)
2444 uschar *user_msg, *log_msg;
2449 gettimeofday(&smtp_connection_start, NULL);
2450 for (smtp_ch_index = 0; smtp_ch_index < SMTP_HBUFF_SIZE; smtp_ch_index++)
2451 smtp_connection_had[smtp_ch_index] = SCH_NONE;
2454 /* Default values for certain variables */
2456 fl.helo_seen = fl.esmtp = fl.helo_accept_junk = FALSE;
2457 smtp_mailcmd_count = 0;
2458 count_nonmail = TRUE_UNSET;
2459 synprot_error_count = unknown_command_count = nonmail_command_count = 0;
2460 smtp_delay_mail = smtp_rlm_base;
2461 fl.auth_advertised = FALSE;
2462 f.smtp_in_pipelining_advertised = f.smtp_in_pipelining_used = FALSE;
2463 f.pipelining_enable = TRUE;
2464 sync_cmd_limit = NON_SYNC_CMD_NON_PIPELINING;
2465 fl.smtp_exit_function_called = FALSE; /* For avoiding loop in not-quit exit */
2467 /* If receiving by -bs from a trusted user, or testing with -bh, we allow
2468 authentication settings from -oMaa to remain in force. */
2470 if (!host_checking && !f.sender_host_notsocket)
2471 sender_host_auth_pubname = sender_host_authenticated = NULL;
2472 authenticated_by = NULL;
2475 tls_in.cipher = tls_in.peerdn = NULL;
2476 tls_in.ourcert = tls_in.peercert = NULL;
2478 tls_in.ocsp = OCSP_NOT_REQ;
2479 fl.tls_advertised = FALSE;
2480 # ifdef EXPERIMENTAL_REQUIRETLS
2481 fl.requiretls_advertised = FALSE;
2484 fl.dsn_advertised = FALSE;
2486 fl.smtputf8_advertised = FALSE;
2489 /* Reset ACL connection variables */
2493 /* Allow for trailing 0 in the command and data buffers. */
2495 if (!(smtp_cmd_buffer = US malloc(2*SMTP_CMD_BUFFER_SIZE + 2)))
2496 log_write(0, LOG_MAIN|LOG_PANIC_DIE,
2497 "malloc() failed for SMTP command buffer");
2499 smtp_cmd_buffer[0] = 0;
2500 smtp_data_buffer = smtp_cmd_buffer + SMTP_CMD_BUFFER_SIZE + 1;
2502 /* For batched input, the protocol setting can be overridden from the
2503 command line by a trusted caller. */
2505 if (smtp_batched_input)
2507 if (!received_protocol) received_protocol = US"local-bsmtp";
2510 /* For non-batched SMTP input, the protocol setting is forced here. It will be
2511 reset later if any of EHLO/AUTH/STARTTLS are received. */
2515 (sender_host_address ? protocols : protocols_local) [pnormal];
2517 /* Set up the buffer for inputting using direct read() calls, and arrange to
2518 call the local functions instead of the standard C ones. Place a NUL at the
2519 end of the buffer to safety-stop C-string reads from it. */
2521 if (!(smtp_inbuffer = US malloc(IN_BUFFER_SIZE)))
2522 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "malloc() failed for SMTP input buffer");
2523 smtp_inbuffer[IN_BUFFER_SIZE-1] = '\0';
2525 receive_getc = smtp_getc;
2526 receive_getbuf = smtp_getbuf;
2527 receive_get_cache = smtp_get_cache;
2528 receive_ungetc = smtp_ungetc;
2529 receive_feof = smtp_feof;
2530 receive_ferror = smtp_ferror;
2531 receive_smtp_buffered = smtp_buffered;
2532 smtp_inptr = smtp_inend = smtp_inbuffer;
2533 smtp_had_eof = smtp_had_error = 0;
2535 /* Set up the message size limit; this may be host-specific */
2537 thismessage_size_limit = expand_string_integer(message_size_limit, TRUE);
2538 if (expand_string_message)
2540 if (thismessage_size_limit == -1)
2541 log_write(0, LOG_MAIN|LOG_PANIC, "unable to expand message_size_limit: "
2542 "%s", expand_string_message);
2544 log_write(0, LOG_MAIN|LOG_PANIC, "invalid message_size_limit: "
2545 "%s", expand_string_message);
2546 smtp_closedown(US"Temporary local problem - please try later");
2550 /* When a message is input locally via the -bs or -bS options, sender_host_
2551 unknown is set unless -oMa was used to force an IP address, in which case it
2552 is checked like a real remote connection. When -bs is used from inetd, this
2553 flag is not set, causing the sending host to be checked. The code that deals
2554 with IP source routing (if configured) is never required for -bs or -bS and
2555 the flag sender_host_notsocket is used to suppress it.
2557 If smtp_accept_max and smtp_accept_reserve are set, keep some connections in
2558 reserve for certain hosts and/or networks. */
2560 if (!f.sender_host_unknown)
2563 BOOL reserved_host = FALSE;
2565 /* Look up IP options (source routing info) on the socket if this is not an
2566 -oMa "host", and if any are found, log them and drop the connection.
2568 Linux (and others now, see below) is different to everyone else, so there
2569 has to be some conditional compilation here. Versions of Linux before 2.1.15
2570 used a structure whose name was "options". Somebody finally realized that
2571 this name was silly, and it got changed to "ip_options". I use the
2572 newer name here, but there is a fudge in the script that sets up os.h
2573 to define a macro in older Linux systems.
2575 Sigh. Linux is a fast-moving target. Another generation of Linux uses
2576 glibc 2, which has chosen ip_opts for the structure name. This is now
2577 really a glibc thing rather than a Linux thing, so the condition name
2578 has been changed to reflect this. It is relevant also to GNU/Hurd.
2580 Mac OS 10.x (Darwin) is like the later glibc versions, but without the
2581 setting of the __GLIBC__ macro, so we can't detect it automatically. There's
2582 a special macro defined in the os.h file.
2584 Some DGUX versions on older hardware appear not to support IP options at
2585 all, so there is now a general macro which can be set to cut out this
2588 How to do this properly in IPv6 is not yet known. */
2590 #if !HAVE_IPV6 && !defined(NO_IP_OPTIONS)
2592 #ifdef GLIBC_IP_OPTIONS
2593 #if (!defined __GLIBC__) || (__GLIBC__ < 2)
2598 #elif defined DARWIN_IP_OPTIONS
2604 if (!host_checking && !f.sender_host_notsocket)
2607 EXIM_SOCKLEN_T optlen = sizeof(struct ip_options) + MAX_IPOPTLEN;
2608 struct ip_options *ipopt = store_get(optlen);
2610 struct ip_opts ipoptblock;
2611 struct ip_opts *ipopt = &ipoptblock;
2612 EXIM_SOCKLEN_T optlen = sizeof(ipoptblock);
2614 struct ipoption ipoptblock;
2615 struct ipoption *ipopt = &ipoptblock;
2616 EXIM_SOCKLEN_T optlen = sizeof(ipoptblock);
2619 /* Occasional genuine failures of getsockopt() have been seen - for
2620 example, "reset by peer". Therefore, just log and give up on this
2621 call, unless the error is ENOPROTOOPT. This error is given by systems
2622 that have the interfaces but not the mechanism - e.g. GNU/Hurd at the time
2623 of writing. So for that error, carry on - we just can't do an IP options
2626 DEBUG(D_receive) debug_printf("checking for IP options\n");
2628 if (getsockopt(fileno(smtp_out), IPPROTO_IP, IP_OPTIONS, US (ipopt),
2631 if (errno != ENOPROTOOPT)
2633 log_write(0, LOG_MAIN, "getsockopt() failed from %s: %s",
2634 host_and_ident(FALSE), strerror(errno));
2635 smtp_printf("451 SMTP service not available\r\n", FALSE);
2640 /* Deal with any IP options that are set. On the systems I have looked at,
2641 the value of MAX_IPOPTLEN has been 40, meaning that there should never be
2642 more logging data than will fit in big_buffer. Nevertheless, after somebody
2643 questioned this code, I've added in some paranoid checking. */
2645 else if (optlen > 0)
2647 uschar *p = big_buffer;
2648 uschar *pend = big_buffer + big_buffer_size;
2651 struct in_addr addr;
2654 uschar *optstart = US (ipopt->__data);
2656 uschar *optstart = US (ipopt->ip_opts);
2658 uschar *optstart = US (ipopt->ipopt_list);
2661 DEBUG(D_receive) debug_printf("IP options exist\n");
2663 Ustrcpy(p, "IP options on incoming call:");
2666 for (uschar * opt = optstart; opt && opt < US (ipopt) + optlen; )
2679 if (!string_format(p, pend-p, " %s [@%s",
2680 (*opt == IPOPT_SSRR)? "SSRR" : "LSRR",
2682 inet_ntoa(*((struct in_addr *)(&(ipopt->faddr))))))
2684 inet_ntoa(ipopt->ip_dst)))
2686 inet_ntoa(ipopt->ipopt_dst)))
2694 optcount = (opt[1] - 3) / sizeof(struct in_addr);
2696 while (optcount-- > 0)
2698 memcpy(&addr, adptr, sizeof(addr));
2699 if (!string_format(p, pend - p - 1, "%s%s",
2700 (optcount == 0)? ":" : "@", inet_ntoa(addr)))
2706 adptr += sizeof(struct in_addr);
2714 if (pend - p < 4 + 3*opt[1]) { opt = NULL; break; }
2717 for (int i = 0; i < opt[1]; i++)
2718 p += sprintf(CS p, "%2.2x ", opt[i]);
2726 log_write(0, LOG_MAIN, "%s", big_buffer);
2728 /* Refuse any call with IP options. This is what tcpwrappers 7.5 does. */
2730 log_write(0, LOG_MAIN|LOG_REJECT,
2731 "connection from %s refused (IP options)", host_and_ident(FALSE));
2733 smtp_printf("554 SMTP service not available\r\n", FALSE);
2737 /* Length of options = 0 => there are no options */
2739 else DEBUG(D_receive) debug_printf("no IP options found\n");
2741 #endif /* HAVE_IPV6 && !defined(NO_IP_OPTIONS) */
2743 /* Set keep-alive in socket options. The option is on by default. This
2744 setting is an attempt to get rid of some hanging connections that stick in
2745 read() when the remote end (usually a dialup) goes away. */
2747 if (smtp_accept_keepalive && !f.sender_host_notsocket)
2748 ip_keepalive(fileno(smtp_out), sender_host_address, FALSE);
2750 /* If the current host matches host_lookup, set the name by doing a
2751 reverse lookup. On failure, sender_host_name will be NULL and
2752 host_lookup_failed will be TRUE. This may or may not be serious - optional
2755 if (verify_check_host(&host_lookup) == OK)
2757 (void)host_name_lookup();
2758 host_build_sender_fullhost();
2761 /* Delay this until we have the full name, if it is looked up. */
2763 set_process_info("handling incoming connection from %s",
2764 host_and_ident(FALSE));
2766 /* Expand smtp_receive_timeout, if needed */
2768 if (smtp_receive_timeout_s)
2771 if ( !(exp = expand_string(smtp_receive_timeout_s))
2773 || (smtp_receive_timeout = readconf_readtime(exp, 0, FALSE)) < 0
2775 log_write(0, LOG_MAIN|LOG_PANIC,
2776 "bad value for smtp_receive_timeout: '%s'", exp ? exp : US"");
2779 /* Test for explicit connection rejection */
2781 if (verify_check_host(&host_reject_connection) == OK)
2783 log_write(L_connection_reject, LOG_MAIN|LOG_REJECT, "refused connection "
2784 "from %s (host_reject_connection)", host_and_ident(FALSE));
2785 smtp_printf("554 SMTP service not available\r\n", FALSE);
2789 /* Test with TCP Wrappers if so configured. There is a problem in that
2790 hosts_ctl() returns 0 (deny) under a number of system failure circumstances,
2791 such as disks dying. In these cases, it is desirable to reject with a 4xx
2792 error instead of a 5xx error. There isn't a "right" way to detect such
2793 problems. The following kludge is used: errno is zeroed before calling
2794 hosts_ctl(). If the result is "reject", a 5xx error is given only if the
2795 value of errno is 0 or ENOENT (which happens if /etc/hosts.{allow,deny} does
2798 #ifdef USE_TCP_WRAPPERS
2800 if (!(tcp_wrappers_name = expand_string(tcp_wrappers_daemon_name)))
2801 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "Expansion of \"%s\" "
2802 "(tcp_wrappers_name) failed: %s", string_printing(tcp_wrappers_name),
2803 expand_string_message);
2805 if (!hosts_ctl(tcp_wrappers_name,
2806 sender_host_name ? CS sender_host_name : STRING_UNKNOWN,
2807 sender_host_address ? CS sender_host_address : STRING_UNKNOWN,
2808 sender_ident ? CS sender_ident : STRING_UNKNOWN))
2810 if (errno == 0 || errno == ENOENT)
2812 HDEBUG(D_receive) debug_printf("tcp wrappers rejection\n");
2813 log_write(L_connection_reject,
2814 LOG_MAIN|LOG_REJECT, "refused connection from %s "
2815 "(tcp wrappers)", host_and_ident(FALSE));
2816 smtp_printf("554 SMTP service not available\r\n", FALSE);
2820 int save_errno = errno;
2821 HDEBUG(D_receive) debug_printf("tcp wrappers rejected with unexpected "
2822 "errno value %d\n", save_errno);
2823 log_write(L_connection_reject,
2824 LOG_MAIN|LOG_REJECT, "temporarily refused connection from %s "
2825 "(tcp wrappers errno=%d)", host_and_ident(FALSE), save_errno);
2826 smtp_printf("451 Temporary local problem - please try later\r\n", FALSE);
2832 /* Check for reserved slots. The value of smtp_accept_count has already been
2833 incremented to include this process. */
2835 if (smtp_accept_max > 0 &&
2836 smtp_accept_count > smtp_accept_max - smtp_accept_reserve)
2838 if ((rc = verify_check_host(&smtp_reserve_hosts)) != OK)
2840 log_write(L_connection_reject,
2841 LOG_MAIN, "temporarily refused connection from %s: not in "
2842 "reserve list: connected=%d max=%d reserve=%d%s",
2843 host_and_ident(FALSE), smtp_accept_count - 1, smtp_accept_max,
2844 smtp_accept_reserve, (rc == DEFER)? " (lookup deferred)" : "");
2845 smtp_printf("421 %s: Too many concurrent SMTP connections; "
2846 "please try again later\r\n", FALSE, smtp_active_hostname);
2849 reserved_host = TRUE;
2852 /* If a load level above which only messages from reserved hosts are
2853 accepted is set, check the load. For incoming calls via the daemon, the
2854 check is done in the superior process if there are no reserved hosts, to
2855 save a fork. In all cases, the load average will already be available
2856 in a global variable at this point. */
2858 if (smtp_load_reserve >= 0 &&
2859 load_average > smtp_load_reserve &&
2861 verify_check_host(&smtp_reserve_hosts) != OK)
2863 log_write(L_connection_reject,
2864 LOG_MAIN, "temporarily refused connection from %s: not in "
2865 "reserve list and load average = %.2f", host_and_ident(FALSE),
2866 (double)load_average/1000.0);
2867 smtp_printf("421 %s: Too much load; please try again later\r\n", FALSE,
2868 smtp_active_hostname);
2872 /* Determine whether unqualified senders or recipients are permitted
2873 for this host. Unfortunately, we have to do this every time, in order to
2874 set the flags so that they can be inspected when considering qualifying
2875 addresses in the headers. For a site that permits no qualification, this
2876 won't take long, however. */
2878 f.allow_unqualified_sender =
2879 verify_check_host(&sender_unqualified_hosts) == OK;
2881 f.allow_unqualified_recipient =
2882 verify_check_host(&recipient_unqualified_hosts) == OK;
2884 /* Determine whether HELO/EHLO is required for this host. The requirement
2885 can be hard or soft. */
2887 fl.helo_required = verify_check_host(&helo_verify_hosts) == OK;
2888 if (!fl.helo_required)
2889 fl.helo_verify = verify_check_host(&helo_try_verify_hosts) == OK;
2891 /* Determine whether this hosts is permitted to send syntactic junk
2892 after a HELO or EHLO command. */
2894 fl.helo_accept_junk = verify_check_host(&helo_accept_junk_hosts) == OK;
2897 /* For batch SMTP input we are now done. */
2899 if (smtp_batched_input) return TRUE;
2901 /* If valid Proxy Protocol source is connecting, set up session.
2902 * Failure will not allow any SMTP function other than QUIT. */
2904 #ifdef SUPPORT_PROXY
2905 proxy_session = FALSE;
2906 f.proxy_session_failed = FALSE;
2907 if (check_proxy_protocol_host())
2908 setup_proxy_protocol_host();
2911 /* Start up TLS if tls_on_connect is set. This is for supporting the legacy
2912 smtps port for use with older style SSL MTAs. */
2915 if (tls_in.on_connect)
2917 if (tls_server_start(tls_require_ciphers, &user_msg) != OK)
2918 return smtp_log_tls_fail(user_msg);
2919 cmd_list[CMD_LIST_TLS_AUTH].is_mail_cmd = TRUE;
2923 /* Run the connect ACL if it exists */
2926 if (acl_smtp_connect)
2929 if ((rc = acl_check(ACL_WHERE_CONNECT, NULL, acl_smtp_connect, &user_msg,
2932 (void) smtp_handle_acl_fail(ACL_WHERE_CONNECT, rc, user_msg, log_msg);
2937 /* Output the initial message for a two-way SMTP connection. It may contain
2938 newlines, which then cause a multi-line response to be given. */
2940 code = US"220"; /* Default status code */
2941 esc = US""; /* Default extended status code */
2942 esclen = 0; /* Length of esc */
2946 if (!(s = expand_string(smtp_banner)))
2947 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "Expansion of \"%s\" (smtp_banner) "
2948 "failed: %s", smtp_banner, expand_string_message);
2954 smtp_message_code(&code, &codelen, &s, NULL, TRUE);
2958 esclen = codelen - 4;
2962 /* Remove any terminating newlines; might as well remove trailing space too */
2965 while (p > s && isspace(p[-1])) p--;
2968 /* It seems that CC:Mail is braindead, and assumes that the greeting message
2969 is all contained in a single IP packet. The original code wrote out the
2970 greeting using several calls to fprint/fputc, and on busy servers this could
2971 cause it to be split over more than one packet - which caused CC:Mail to fall
2972 over when it got the second part of the greeting after sending its first
2973 command. Sigh. To try to avoid this, build the complete greeting message
2974 first, and output it in one fell swoop. This gives a better chance of it
2975 ending up as a single packet. */
2977 ss = string_get(256);
2980 do /* At least once, in case we have an empty string */
2983 uschar *linebreak = Ustrchr(p, '\n');
2984 ss = string_catn(ss, code, 3);
2988 ss = string_catn(ss, US" ", 1);
2992 len = linebreak - p;
2993 ss = string_catn(ss, US"-", 1);
2995 ss = string_catn(ss, esc, esclen);
2996 ss = string_catn(ss, p, len);
2997 ss = string_catn(ss, US"\r\n", 2);
3003 /* Before we write the banner, check that there is no input pending, unless
3004 this synchronisation check is disabled. */
3006 #ifdef EXPERIMENTAL_PIPE_CONNECT
3007 fl.pipe_connect_acceptable =
3008 sender_host_address && verify_check_host(&pipe_connect_advertise_hosts) == OK;
3011 if (fl.pipe_connect_acceptable)
3012 f.smtp_in_early_pipe_used = TRUE;
3018 unsigned n = smtp_inend - smtp_inptr;
3021 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP protocol "
3022 "synchronization error (input sent without waiting for greeting): "
3023 "rejected connection from %s input=\"%s\"", host_and_ident(TRUE),
3024 string_printing(string_copyn(smtp_inptr, n)));
3025 smtp_printf("554 SMTP synchronization error\r\n", FALSE);
3029 /* Now output the banner */
3030 /*XXX the ehlo-resp code does its own tls/nontls bit. Maybe subroutine that? */
3033 #ifdef EXPERIMENTAL_PIPE_CONNECT
3034 fl.pipe_connect_acceptable && pipeline_connect_sends(),
3038 string_from_gstring(ss));
3040 /* Attempt to see if we sent the banner before the last ACK of the 3-way
3041 handshake arrived. If so we must have managed a TFO. */
3054 /*************************************************
3055 * Handle SMTP syntax and protocol errors *
3056 *************************************************/
3058 /* Write to the log for SMTP syntax errors in incoming commands, if configured
3059 to do so. Then transmit the error response. The return value depends on the
3060 number of syntax and protocol errors in this SMTP session.
3063 type error type, given as a log flag bit
3064 code response code; <= 0 means don't send a response
3065 data data to reflect in the response (can be NULL)
3066 errmess the error message
3068 Returns: -1 limit of syntax/protocol errors NOT exceeded
3069 +1 limit of syntax/protocol errors IS exceeded
3071 These values fit in with the values of the "done" variable in the main
3072 processing loop in smtp_setup_msg(). */
3075 synprot_error(int type, int code, uschar *data, uschar *errmess)
3079 log_write(type, LOG_MAIN, "SMTP %s error in \"%s\" %s %s",
3080 (type == L_smtp_syntax_error)? "syntax" : "protocol",
3081 string_printing(smtp_cmd_buffer), host_and_ident(TRUE), errmess);
3083 if (++synprot_error_count > smtp_max_synprot_errors)
3086 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
3087 "syntax or protocol errors (last command was \"%s\")",
3088 host_and_ident(FALSE), string_printing(smtp_cmd_buffer));
3093 smtp_printf("%d%c%s%s%s\r\n", FALSE, code, yield == 1 ? '-' : ' ',
3094 data ? data : US"", data ? US": " : US"", errmess);
3096 smtp_printf("%d Too many syntax or protocol errors\r\n", FALSE, code);
3105 /*************************************************
3106 * Send SMTP response, possibly multiline *
3107 *************************************************/
3109 /* There are, it seems, broken clients out there that cannot handle multiline
3110 responses. If no_multiline_responses is TRUE (it can be set from an ACL), we
3111 output nothing for non-final calls, and only the first line for anything else.
3114 code SMTP code, may involve extended status codes
3115 codelen length of smtp code; if > 4 there's an ESC
3116 final FALSE if the last line isn't the final line
3117 msg message text, possibly containing newlines
3123 smtp_respond(uschar* code, int codelen, BOOL final, uschar *msg)
3128 if (!final && f.no_multiline_responses) return;
3133 esclen = codelen - 4;
3136 /* If this is the first output for a (non-batch) RCPT command, see if all RCPTs
3137 have had the same. Note: this code is also present in smtp_printf(). It would
3138 be tidier to have it only in one place, but when it was added, it was easier to
3139 do it that way, so as not to have to mess with the code for the RCPT command,
3140 which sometimes uses smtp_printf() and sometimes smtp_respond(). */
3142 if (fl.rcpt_in_progress)
3144 if (rcpt_smtp_response == NULL)
3145 rcpt_smtp_response = string_copy(msg);
3146 else if (fl.rcpt_smtp_response_same &&
3147 Ustrcmp(rcpt_smtp_response, msg) != 0)
3148 fl.rcpt_smtp_response_same = FALSE;
3149 fl.rcpt_in_progress = FALSE;
3152 /* Now output the message, splitting it up into multiple lines if necessary.
3153 We only handle pipelining these responses as far as nonfinal/final groups,
3154 not the whole MAIL/RCPT/DATA response set. */
3158 uschar *nl = Ustrchr(msg, '\n');
3161 smtp_printf("%.3s%c%.*s%s\r\n", !final, code, final ? ' ':'-', esclen, esc, msg);
3164 else if (nl[1] == 0 || f.no_multiline_responses)
3166 smtp_printf("%.3s%c%.*s%.*s\r\n", !final, code, final ? ' ':'-', esclen, esc,
3167 (int)(nl - msg), msg);
3172 smtp_printf("%.3s-%.*s%.*s\r\n", TRUE, code, esclen, esc, (int)(nl - msg), msg);
3174 while (isspace(*msg)) msg++;
3182 /*************************************************
3183 * Parse user SMTP message *
3184 *************************************************/
3186 /* This function allows for user messages overriding the response code details
3187 by providing a suitable response code string at the start of the message
3188 user_msg. Check the message for starting with a response code and optionally an
3189 extended status code. If found, check that the first digit is valid, and if so,
3190 change the code pointer and length to use the replacement. An invalid code
3191 causes a panic log; in this case, if the log messages is the same as the user
3192 message, we must also adjust the value of the log message to show the code that
3193 is actually going to be used (the original one).
3195 This function is global because it is called from receive.c as well as within
3198 Note that the code length returned includes the terminating whitespace
3199 character, which is always included in the regex match.
3202 code SMTP code, may involve extended status codes
3203 codelen length of smtp code; if > 4 there's an ESC
3205 log_msg optional log message, to be adjusted with the new SMTP code
3206 check_valid if true, verify the response code
3212 smtp_message_code(uschar **code, int *codelen, uschar **msg, uschar **log_msg,
3218 if (!msg || !*msg) return;
3220 if ((n = pcre_exec(regex_smtp_code, NULL, CS *msg, Ustrlen(*msg), 0,
3221 PCRE_EOPT, ovector, sizeof(ovector)/sizeof(int))) < 0) return;
3223 if (check_valid && (*msg)[0] != (*code)[0])
3225 log_write(0, LOG_MAIN|LOG_PANIC, "configured error code starts with "
3226 "incorrect digit (expected %c) in \"%s\"", (*code)[0], *msg);
3227 if (log_msg != NULL && *log_msg == *msg)
3228 *log_msg = string_sprintf("%s %s", *code, *log_msg + ovector[1]);
3233 *codelen = ovector[1]; /* Includes final space */
3235 *msg += ovector[1]; /* Chop the code off the message */
3242 /*************************************************
3243 * Handle an ACL failure *
3244 *************************************************/
3246 /* This function is called when acl_check() fails. As well as calls from within
3247 this module, it is called from receive.c for an ACL after DATA. It sorts out
3248 logging the incident, and sends the error response. A message containing
3249 newlines is turned into a multiline SMTP response, but for logging, only the
3252 There's a table of default permanent failure response codes to use in
3253 globals.c, along with the table of names. VFRY is special. Despite RFC1123 it
3254 defaults disabled in Exim. However, discussion in connection with RFC 821bis
3255 (aka RFC 2821) has concluded that the response should be 252 in the disabled
3256 state, because there are broken clients that try VRFY before RCPT. A 5xx
3257 response should be given only when the address is positively known to be
3258 undeliverable. Sigh. We return 252 if there is no VRFY ACL or it provides
3259 no explicit code, but if there is one we let it know best.
3260 Also, for ETRN, 458 is given on refusal, and for AUTH, 503.
3262 From Exim 4.63, it is possible to override the response code details by
3263 providing a suitable response code string at the start of the message provided
3264 in user_msg. The code's first digit is checked for validity.
3267 where where the ACL was called from
3269 user_msg a message that can be included in an SMTP response
3270 log_msg a message for logging
3272 Returns: 0 in most cases
3273 2 if the failure code was FAIL_DROP, in which case the
3274 SMTP connection should be dropped (this value fits with the
3275 "done" variable in smtp_setup_msg() below)
3279 smtp_handle_acl_fail(int where, int rc, uschar *user_msg, uschar *log_msg)
3281 BOOL drop = rc == FAIL_DROP;
3285 uschar *sender_info = US"";
3287 #ifdef WITH_CONTENT_SCAN
3288 where == ACL_WHERE_MIME ? US"during MIME ACL checks" :
3290 where == ACL_WHERE_PREDATA ? US"DATA" :
3291 where == ACL_WHERE_DATA ? US"after DATA" :
3292 #ifndef DISABLE_PRDR
3293 where == ACL_WHERE_PRDR ? US"after DATA PRDR" :
3296 string_sprintf("%s %s", acl_wherenames[where], smtp_cmd_data) :
3297 string_sprintf("%s in \"connect\" ACL", acl_wherenames[where]);
3299 if (drop) rc = FAIL;
3301 /* Set the default SMTP code, and allow a user message to change it. */
3303 smtp_code = rc == FAIL ? acl_wherecodes[where] : US"451";
3304 smtp_message_code(&smtp_code, &codelen, &user_msg, &log_msg,
3305 where != ACL_WHERE_VRFY);
3307 /* We used to have sender_address here; however, there was a bug that was not
3308 updating sender_address after a rewrite during a verify. When this bug was
3309 fixed, sender_address at this point became the rewritten address. I'm not sure
3310 this is what should be logged, so I've changed to logging the unrewritten
3311 address to retain backward compatibility. */
3313 #ifndef WITH_CONTENT_SCAN
3314 if (where == ACL_WHERE_RCPT || where == ACL_WHERE_DATA)
3316 if (where == ACL_WHERE_RCPT || where == ACL_WHERE_DATA || where == ACL_WHERE_MIME)
3319 sender_info = string_sprintf("F=<%s>%s%s%s%s ",
3320 sender_address_unrewritten ? sender_address_unrewritten : sender_address,
3321 sender_host_authenticated ? US" A=" : US"",
3322 sender_host_authenticated ? sender_host_authenticated : US"",
3323 sender_host_authenticated && authenticated_id ? US":" : US"",
3324 sender_host_authenticated && authenticated_id ? authenticated_id : US""
3328 /* If there's been a sender verification failure with a specific message, and
3329 we have not sent a response about it yet, do so now, as a preliminary line for
3330 failures, but not defers. However, always log it for defer, and log it for fail
3331 unless the sender_verify_fail log selector has been turned off. */
3333 if (sender_verified_failed &&
3334 !testflag(sender_verified_failed, af_sverify_told))
3336 BOOL save_rcpt_in_progress = fl.rcpt_in_progress;
3337 fl.rcpt_in_progress = FALSE; /* So as not to treat these as the error */
3339 setflag(sender_verified_failed, af_sverify_told);
3341 if (rc != FAIL || LOGGING(sender_verify_fail))
3342 log_write(0, LOG_MAIN|LOG_REJECT, "%s sender verify %s for <%s>%s",
3343 host_and_ident(TRUE),
3344 ((sender_verified_failed->special_action & 255) == DEFER)? "defer":"fail",
3345 sender_verified_failed->address,
3346 (sender_verified_failed->message == NULL)? US"" :
3347 string_sprintf(": %s", sender_verified_failed->message));
3349 if (rc == FAIL && sender_verified_failed->user_message)
3350 smtp_respond(smtp_code, codelen, FALSE, string_sprintf(
3351 testflag(sender_verified_failed, af_verify_pmfail)?
3352 "Postmaster verification failed while checking <%s>\n%s\n"
3353 "Several RFCs state that you are required to have a postmaster\n"
3354 "mailbox for each mail domain. This host does not accept mail\n"
3355 "from domains whose servers reject the postmaster address."
3357 testflag(sender_verified_failed, af_verify_nsfail)?
3358 "Callback setup failed while verifying <%s>\n%s\n"
3359 "The initial connection, or a HELO or MAIL FROM:<> command was\n"
3360 "rejected. Refusing MAIL FROM:<> does not help fight spam, disregards\n"
3361 "RFC requirements, and stops you from receiving standard bounce\n"
3362 "messages. This host does not accept mail from domains whose servers\n"
3365 "Verification failed for <%s>\n%s",
3366 sender_verified_failed->address,
3367 sender_verified_failed->user_message));
3369 fl.rcpt_in_progress = save_rcpt_in_progress;
3372 /* Sort out text for logging */
3374 log_msg = log_msg ? string_sprintf(": %s", log_msg) : US"";
3375 if ((lognl = Ustrchr(log_msg, '\n'))) *lognl = 0;
3377 /* Send permanent failure response to the command, but the code used isn't
3378 always a 5xx one - see comments at the start of this function. If the original
3379 rc was FAIL_DROP we drop the connection and yield 2. */
3382 smtp_respond(smtp_code, codelen, TRUE,
3383 user_msg ? user_msg : US"Administrative prohibition");
3385 /* Send temporary failure response to the command. Don't give any details,
3386 unless acl_temp_details is set. This is TRUE for a callout defer, a "defer"
3387 verb, and for a header verify when smtp_return_error_details is set.
3389 This conditional logic is all somewhat of a mess because of the odd
3390 interactions between temp_details and return_error_details. One day it should
3391 be re-implemented in a tidier fashion. */
3394 if (f.acl_temp_details && user_msg)
3396 if ( smtp_return_error_details
3397 && sender_verified_failed
3398 && sender_verified_failed->message
3400 smtp_respond(smtp_code, codelen, FALSE, sender_verified_failed->message);
3402 smtp_respond(smtp_code, codelen, TRUE, user_msg);
3405 smtp_respond(smtp_code, codelen, TRUE,
3406 US"Temporary local problem - please try later");
3408 /* Log the incident to the logs that are specified by log_reject_target
3409 (default main, reject). This can be empty to suppress logging of rejections. If
3410 the connection is not forcibly to be dropped, return 0. Otherwise, log why it
3411 is closing if required and return 2. */
3413 if (log_reject_target != 0)
3416 gstring * g = s_tlslog(NULL);
3417 uschar * tls = string_from_gstring(g);
3418 if (!tls) tls = US"";
3420 uschar * tls = US"";
3422 log_write(where == ACL_WHERE_CONNECT ? L_connection_reject : 0,
3423 log_reject_target, "%s%s%s %s%srejected %s%s",
3424 LOGGING(dnssec) && sender_host_dnssec ? US" DS" : US"",
3425 host_and_ident(TRUE),
3428 rc == FAIL ? US"" : US"temporarily ",
3432 if (!drop) return 0;
3434 log_write(L_smtp_connection, LOG_MAIN, "%s closed by DROP in ACL",
3435 smtp_get_connection_info());
3437 /* Run the not-quit ACL, but without any custom messages. This should not be a
3438 problem, because we get here only if some other ACL has issued "drop", and
3439 in that case, *its* custom messages will have been used above. */
3441 smtp_notquit_exit(US"acl-drop", NULL, NULL);
3448 /*************************************************
3449 * Handle SMTP exit when QUIT is not given *
3450 *************************************************/
3452 /* This function provides a logging/statistics hook for when an SMTP connection
3453 is dropped on the floor or the other end goes away. It's a global function
3454 because it's called from receive.c as well as this module. As well as running
3455 the NOTQUIT ACL, if there is one, this function also outputs a final SMTP
3456 response, either with a custom message from the ACL, or using a default. There
3457 is one case, however, when no message is output - after "drop". In that case,
3458 the ACL that obeyed "drop" has already supplied the custom message, and NULL is
3459 passed to this function.
3461 In case things go wrong while processing this function, causing an error that
3462 may re-enter this function, there is a recursion check.
3465 reason What $smtp_notquit_reason will be set to in the ACL;
3466 if NULL, the ACL is not run
3467 code The error code to return as part of the response
3468 defaultrespond The default message if there's no user_msg
3474 smtp_notquit_exit(uschar *reason, uschar *code, uschar *defaultrespond, ...)
3477 uschar *user_msg = NULL;
3478 uschar *log_msg = NULL;
3480 /* Check for recursive call */
3482 if (fl.smtp_exit_function_called)
3484 log_write(0, LOG_PANIC, "smtp_notquit_exit() called more than once (%s)",
3488 fl.smtp_exit_function_called = TRUE;
3490 /* Call the not-QUIT ACL, if there is one, unless no reason is given. */
3492 if (acl_smtp_notquit && reason)
3494 smtp_notquit_reason = reason;
3495 if ((rc = acl_check(ACL_WHERE_NOTQUIT, NULL, acl_smtp_notquit, &user_msg,
3496 &log_msg)) == ERROR)
3497 log_write(0, LOG_MAIN|LOG_PANIC, "ACL for not-QUIT returned ERROR: %s",
3501 /* If the connection was dropped, we certainly are no longer talking TLS */
3502 tls_in.active.sock = -1;
3504 /* Write an SMTP response if we are expected to give one. As the default
3505 responses are all internal, they should be reasonable size. */
3507 if (code && defaultrespond)
3510 smtp_respond(code, 3, TRUE, user_msg);
3516 va_start(ap, defaultrespond);
3517 g = string_vformat(NULL, TRUE, CS defaultrespond, ap);
3519 smtp_printf("%s %s\r\n", FALSE, code, string_from_gstring(g));
3528 /*************************************************
3529 * Verify HELO argument *
3530 *************************************************/
3532 /* This function is called if helo_verify_hosts or helo_try_verify_hosts is
3533 matched. It is also called from ACL processing if verify = helo is used and
3534 verification was not previously tried (i.e. helo_try_verify_hosts was not
3535 matched). The result of its processing is to set helo_verified and
3536 helo_verify_failed. These variables should both be FALSE for this function to
3539 Note that EHLO/HELO is legitimately allowed to quote an address literal. Allow
3540 for IPv6 ::ffff: literals.
3543 Returns: TRUE if testing was completed;
3544 FALSE on a temporary failure
3548 smtp_verify_helo(void)
3552 HDEBUG(D_receive) debug_printf("verifying EHLO/HELO argument \"%s\"\n",
3555 if (sender_helo_name == NULL)
3557 HDEBUG(D_receive) debug_printf("no EHLO/HELO command was issued\n");
3560 /* Deal with the case of -bs without an IP address */
3562 else if (sender_host_address == NULL)
3564 HDEBUG(D_receive) debug_printf("no client IP address: assume success\n");
3565 f.helo_verified = TRUE;
3568 /* Deal with the more common case when there is a sending IP address */
3570 else if (sender_helo_name[0] == '[')
3572 f.helo_verified = Ustrncmp(sender_helo_name+1, sender_host_address,
3573 Ustrlen(sender_host_address)) == 0;
3576 if (!f.helo_verified)
3578 if (strncmpic(sender_host_address, US"::ffff:", 7) == 0)
3579 f.helo_verified = Ustrncmp(sender_helo_name + 1,
3580 sender_host_address + 7, Ustrlen(sender_host_address) - 7) == 0;
3585 { if (f.helo_verified) debug_printf("matched host address\n"); }
3588 /* Do a reverse lookup if one hasn't already given a positive or negative
3589 response. If that fails, or the name doesn't match, try checking with a forward
3594 if (sender_host_name == NULL && !host_lookup_failed)
3595 yield = host_name_lookup() != DEFER;
3597 /* If a host name is known, check it and all its aliases. */
3599 if (sender_host_name)
3600 if ((f.helo_verified = strcmpic(sender_host_name, sender_helo_name) == 0))
3602 sender_helo_dnssec = sender_host_dnssec;
3603 HDEBUG(D_receive) debug_printf("matched host name\n");
3607 uschar **aliases = sender_host_aliases;
3609 if ((f.helo_verified = strcmpic(*aliases++, sender_helo_name) == 0))
3611 sender_helo_dnssec = sender_host_dnssec;
3615 HDEBUG(D_receive) if (f.helo_verified)
3616 debug_printf("matched alias %s\n", *(--aliases));
3619 /* Final attempt: try a forward lookup of the helo name */
3621 if (!f.helo_verified)
3625 {.name = sender_helo_name, .address = NULL, .mx = MX_NONE, .next = NULL};
3627 {.request = US"*", .require = US""};
3629 HDEBUG(D_receive) debug_printf("getting IP address for %s\n",
3631 rc = host_find_bydns(&h, NULL, HOST_FIND_BY_A | HOST_FIND_BY_AAAA,
3632 NULL, NULL, NULL, &d, NULL, NULL);
3633 if (rc == HOST_FOUND || rc == HOST_FOUND_LOCAL)
3634 for (host_item * hh = &h; hh; hh = hh->next)
3635 if (Ustrcmp(hh->address, sender_host_address) == 0)
3637 f.helo_verified = TRUE;
3638 if (h.dnssec == DS_YES) sender_helo_dnssec = TRUE;
3640 debug_printf("IP address for %s matches calling address\n"
3641 "Forward DNS security status: %sverified\n",
3642 sender_helo_name, sender_helo_dnssec ? "" : "un");
3648 if (!f.helo_verified) f.helo_verify_failed = TRUE; /* We've tried ... */
3655 /*************************************************
3656 * Send user response message *
3657 *************************************************/
3659 /* This function is passed a default response code and a user message. It calls
3660 smtp_message_code() to check and possibly modify the response code, and then
3661 calls smtp_respond() to transmit the response. I put this into a function
3662 just to avoid a lot of repetition.
3665 code the response code
3666 user_msg the user message
3672 smtp_user_msg(uschar *code, uschar *user_msg)
3675 smtp_message_code(&code, &len, &user_msg, NULL, TRUE);
3676 smtp_respond(code, len, TRUE, user_msg);
3682 smtp_in_auth(auth_instance *au, uschar ** s, uschar ** ss)
3684 const uschar *set_id = NULL;
3687 /* Run the checking code, passing the remainder of the command line as
3688 data. Initials the $auth<n> variables as empty. Initialize $0 empty and set
3689 it as the only set numerical variable. The authenticator may set $auth<n>
3690 and also set other numeric variables. The $auth<n> variables are preferred
3691 nowadays; the numerical variables remain for backwards compatibility.
3693 Afterwards, have a go at expanding the set_id string, even if
3694 authentication failed - for bad passwords it can be useful to log the
3695 userid. On success, require set_id to expand and exist, and put it in
3696 authenticated_id. Save this in permanent store, as the working store gets
3697 reset at HELO, RSET, etc. */
3699 for (int i = 0; i < AUTH_VARS; i++) auth_vars[i] = NULL;
3701 expand_nlength[0] = 0; /* $0 contains nothing */
3703 rc = (au->info->servercode)(au, smtp_cmd_data);
3704 if (au->set_id) set_id = expand_string(au->set_id);
3705 expand_nmax = -1; /* Reset numeric variables */
3706 for (int i = 0; i < AUTH_VARS; i++) auth_vars[i] = NULL; /* Reset $auth<n> */
3708 /* The value of authenticated_id is stored in the spool file and printed in
3709 log lines. It must not contain binary zeros or newline characters. In
3710 normal use, it never will, but when playing around or testing, this error
3711 can (did) happen. To guard against this, ensure that the id contains only
3712 printing characters. */
3714 if (set_id) set_id = string_printing(set_id);
3716 /* For the non-OK cases, set up additional logging data if set_id
3720 set_id = set_id && *set_id
3721 ? string_sprintf(" (set_id=%s)", set_id) : US"";
3723 /* Switch on the result */
3728 if (!au->set_id || set_id) /* Complete success */
3730 if (set_id) authenticated_id = string_copy_malloc(set_id);
3731 sender_host_authenticated = au->name;
3732 sender_host_auth_pubname = au->public_name;
3733 authentication_failed = FALSE;
3734 authenticated_fail_id = NULL; /* Impossible to already be set? */
3737 (sender_host_address ? protocols : protocols_local)
3738 [pextend + pauthed + (tls_in.active.sock >= 0 ? pcrpted:0)];
3739 *s = *ss = US"235 Authentication succeeded";
3740 authenticated_by = au;
3744 /* Authentication succeeded, but we failed to expand the set_id string.
3745 Treat this as a temporary error. */
3747 auth_defer_msg = expand_string_message;
3751 if (set_id) authenticated_fail_id = string_copy_malloc(set_id);
3752 *s = string_sprintf("435 Unable to authenticate at present%s",
3753 auth_defer_user_msg);
3754 *ss = string_sprintf("435 Unable to authenticate at present%s: %s",
3755 set_id, auth_defer_msg);
3759 *s = *ss = US"501 Invalid base64 data";
3763 *s = *ss = US"501 Authentication cancelled";
3767 *s = *ss = US"553 Initial data not expected";
3771 if (set_id) authenticated_fail_id = string_copy_malloc(set_id);
3772 *s = US"535 Incorrect authentication data";
3773 *ss = string_sprintf("535 Incorrect authentication data%s", set_id);
3777 if (set_id) authenticated_fail_id = string_copy_malloc(set_id);
3778 *s = US"435 Internal error";
3779 *ss = string_sprintf("435 Internal error%s: return %d from authentication "
3780 "check", set_id, rc);
3792 qualify_recipient(uschar ** recipient, uschar * smtp_cmd_data, uschar * tag)
3795 if (f.allow_unqualified_recipient || strcmpic(*recipient, US"postmaster") == 0)
3797 DEBUG(D_receive) debug_printf("unqualified address %s accepted\n",
3799 rd = Ustrlen(recipient) + 1;
3800 *recipient = rewrite_address_qualify(*recipient, TRUE);
3803 smtp_printf("501 %s: recipient address must contain a domain\r\n", FALSE,
3805 log_write(L_smtp_syntax_error,
3806 LOG_MAIN|LOG_REJECT, "unqualified %s rejected: <%s> %s%s",
3807 tag, *recipient, host_and_ident(TRUE), host_lookup_msg);
3815 smtp_quit_handler(uschar ** user_msgp, uschar ** log_msgp)
3818 incomplete_transaction_log(US"QUIT");
3821 int rc = acl_check(ACL_WHERE_QUIT, NULL, acl_smtp_quit, user_msgp, log_msgp);
3823 log_write(0, LOG_MAIN|LOG_PANIC, "ACL for QUIT returned ERROR: %s",
3828 (void) setsockopt(fileno(smtp_out), IPPROTO_TCP, TCP_CORK, US &on, sizeof(on));
3832 smtp_respond(US"221", 3, TRUE, *user_msgp);
3834 smtp_printf("221 %s closing connection\r\n", FALSE, smtp_active_hostname);
3837 tls_close(NULL, TLS_SHUTDOWN_NOWAIT);
3840 log_write(L_smtp_connection, LOG_MAIN, "%s closed by QUIT",
3841 smtp_get_connection_info());
3846 smtp_rset_handler(void)
3849 incomplete_transaction_log(US"RSET");
3850 smtp_printf("250 Reset OK\r\n", FALSE);
3851 cmd_list[CMD_LIST_RSET].is_mail_cmd = FALSE;
3856 /*************************************************
3857 * Initialize for SMTP incoming message *
3858 *************************************************/
3860 /* This function conducts the initial dialogue at the start of an incoming SMTP
3861 message, and builds a list of recipients. However, if the incoming message
3862 is part of a batch (-bS option) a separate function is called since it would
3863 be messy having tests splattered about all over this function. This function
3864 therefore handles the case where interaction is occurring. The input and output
3865 files are set up in smtp_in and smtp_out.
3867 The global recipients_list is set to point to a vector of recipient_item
3868 blocks, whose number is given by recipients_count. This is extended by the
3869 receive_add_recipient() function. The global variable sender_address is set to
3870 the sender's address. The yield is +1 if a message has been successfully
3871 started, 0 if a QUIT command was encountered or the connection was refused from
3872 the particular host, or -1 if the connection was lost.
3876 Returns: > 0 message successfully started (reached DATA)
3877 = 0 QUIT read or end of file reached or call refused
3882 smtp_setup_msg(void)
3885 BOOL toomany = FALSE;
3886 BOOL discarded = FALSE;
3887 BOOL last_was_rej_mail = FALSE;
3888 BOOL last_was_rcpt = FALSE;
3889 void *reset_point = store_get(0);
3891 DEBUG(D_receive) debug_printf("smtp_setup_msg entered\n");
3893 /* Reset for start of new message. We allow one RSET not to be counted as a
3894 nonmail command, for those MTAs that insist on sending it between every
3895 message. Ditto for EHLO/HELO and for STARTTLS, to allow for going in and out of
3896 TLS between messages (an Exim client may do this if it has messages queued up
3897 for the host). Note: we do NOT reset AUTH at this point. */
3899 smtp_reset(reset_point);
3900 message_ended = END_NOTSTARTED;
3902 chunking_state = f.chunking_offered ? CHUNKING_OFFERED : CHUNKING_NOT_OFFERED;
3904 cmd_list[CMD_LIST_RSET].is_mail_cmd = TRUE;
3905 cmd_list[CMD_LIST_HELO].is_mail_cmd = TRUE;
3906 cmd_list[CMD_LIST_EHLO].is_mail_cmd = TRUE;
3908 cmd_list[CMD_LIST_STARTTLS].is_mail_cmd = TRUE;
3911 /* Set the local signal handler for SIGTERM - it tries to end off tidily */
3913 had_command_sigterm = 0;
3914 os_non_restarting_signal(SIGTERM, command_sigterm_handler);
3916 /* Batched SMTP is handled in a different function. */
3918 if (smtp_batched_input) return smtp_setup_batch_msg();
3920 /* Deal with SMTP commands. This loop is exited by setting done to a POSITIVE
3921 value. The values are 2 larger than the required yield of the function. */
3925 const uschar **argv;
3926 uschar *etrn_command;
3927 uschar *etrn_serialize_key;
3929 uschar *log_msg, *smtp_code;
3930 uschar *user_msg = NULL;
3931 uschar *recipient = NULL;
3932 uschar *hello = NULL;
3934 BOOL was_rej_mail = FALSE;
3935 BOOL was_rcpt = FALSE;
3936 void (*oldsignal)(int);
3938 int start, end, sender_domain, recipient_domain;
3941 uschar *orcpt = NULL;
3946 /* Check once per STARTTLS or SSL-on-connect for a TLS AUTH */
3947 if ( tls_in.active.sock >= 0
3949 && tls_in.certificate_verified
3950 && cmd_list[CMD_LIST_TLS_AUTH].is_mail_cmd
3953 cmd_list[CMD_LIST_TLS_AUTH].is_mail_cmd = FALSE;
3955 for (auth_instance * au = auths; au; au = au->next)
3956 if (strcmpic(US"tls", au->driver_name) == 0)
3959 && (rc = acl_check(ACL_WHERE_AUTH, NULL, acl_smtp_auth,
3960 &user_msg, &log_msg)) != OK
3962 done = smtp_handle_acl_fail(ACL_WHERE_AUTH, rc, user_msg, log_msg);
3965 smtp_cmd_data = NULL;
3967 if (smtp_in_auth(au, &s, &ss) == OK)
3968 { DEBUG(D_auth) debug_printf("tls auth succeeded\n"); }
3970 { DEBUG(D_auth) debug_printf("tls auth not succeeded\n"); }
3978 if (smtp_in) /* Avoid pure-ACKs while in cmd pingpong phase */
3979 (void) setsockopt(fileno(smtp_in), IPPROTO_TCP, TCP_QUICKACK,
3980 US &off, sizeof(off));
3983 switch(smtp_read_command(
3984 #ifdef EXPERIMENTAL_PIPE_CONNECT
3985 !fl.pipe_connect_acceptable,
3989 GETC_BUFFER_UNLIMITED))
3991 /* The AUTH command is not permitted to occur inside a transaction, and may
3992 occur successfully only once per connection. Actually, that isn't quite
3993 true. When TLS is started, all previous information about a connection must
3994 be discarded, so a new AUTH is permitted at that time.
3996 AUTH may only be used when it has been advertised. However, it seems that
3997 there are clients that send AUTH when it hasn't been advertised, some of
3998 them even doing this after HELO. And there are MTAs that accept this. Sigh.
3999 So there's a get-out that allows this to happen.
4001 AUTH is initially labelled as a "nonmail command" so that one occurrence
4002 doesn't get counted. We change the label here so that multiple failing
4003 AUTHS will eventually hit the nonmail threshold. */
4007 authentication_failed = TRUE;
4008 cmd_list[CMD_LIST_AUTH].is_mail_cmd = FALSE;
4010 if (!fl.auth_advertised && !f.allow_auth_unadvertised)
4012 done = synprot_error(L_smtp_protocol_error, 503, NULL,
4013 US"AUTH command used when not advertised");
4016 if (sender_host_authenticated)
4018 done = synprot_error(L_smtp_protocol_error, 503, NULL,
4019 US"already authenticated");
4024 done = synprot_error(L_smtp_protocol_error, 503, NULL,
4025 US"not permitted in mail transaction");
4032 && (rc = acl_check(ACL_WHERE_AUTH, NULL, acl_smtp_auth,
4033 &user_msg, &log_msg)) != OK
4036 done = smtp_handle_acl_fail(ACL_WHERE_AUTH, rc, user_msg, log_msg);
4040 /* Find the name of the requested authentication mechanism. */
4043 while ((c = *smtp_cmd_data) != 0 && !isspace(c))
4045 if (!isalnum(c) && c != '-' && c != '_')
4047 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4048 US"invalid character in authentication mechanism name");
4054 /* If not at the end of the line, we must be at white space. Terminate the
4055 name and move the pointer on to any data that may be present. */
4057 if (*smtp_cmd_data != 0)
4059 *smtp_cmd_data++ = 0;
4060 while (isspace(*smtp_cmd_data)) smtp_cmd_data++;
4063 /* Search for an authentication mechanism which is configured for use
4064 as a server and which has been advertised (unless, sigh, allow_auth_
4065 unadvertised is set). */
4069 for (au = auths; au; au = au->next)
4070 if (strcmpic(s, au->public_name) == 0 && au->server &&
4071 (au->advertised || f.allow_auth_unadvertised))
4076 c = smtp_in_auth(au, &s, &ss);
4078 smtp_printf("%s\r\n", FALSE, s);
4080 log_write(0, LOG_MAIN|LOG_REJECT, "%s authenticator failed for %s: %s",
4081 au->name, host_and_ident(FALSE), ss);
4084 done = synprot_error(L_smtp_protocol_error, 504, NULL,
4085 string_sprintf("%s authentication mechanism not supported", s));
4088 break; /* AUTH_CMD */
4090 /* The HELO/EHLO commands are permitted to appear in the middle of a
4091 session as well as at the beginning. They have the effect of a reset in
4092 addition to their other functions. Their absence at the start cannot be
4093 taken to be an error.
4097 If the EHLO command is not acceptable to the SMTP server, 501, 500,
4098 or 502 failure replies MUST be returned as appropriate. The SMTP
4099 server MUST stay in the same state after transmitting these replies
4100 that it was in before the EHLO was received.
4102 Therefore, we do not do the reset until after checking the command for
4103 acceptability. This change was made for Exim release 4.11. Previously
4104 it did the reset first. */
4117 HELO_EHLO: /* Common code for HELO and EHLO */
4118 cmd_list[CMD_LIST_HELO].is_mail_cmd = FALSE;
4119 cmd_list[CMD_LIST_EHLO].is_mail_cmd = FALSE;
4121 /* Reject the HELO if its argument was invalid or non-existent. A
4122 successful check causes the argument to be saved in malloc store. */
4124 if (!check_helo(smtp_cmd_data))
4126 smtp_printf("501 Syntactically invalid %s argument(s)\r\n", FALSE, hello);
4128 log_write(0, LOG_MAIN|LOG_REJECT, "rejected %s from %s: syntactically "
4129 "invalid argument(s): %s", hello, host_and_ident(FALSE),
4130 *smtp_cmd_argument == 0 ? US"(no argument given)" :
4131 string_printing(smtp_cmd_argument));
4133 if (++synprot_error_count > smtp_max_synprot_errors)
4135 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
4136 "syntax or protocol errors (last command was \"%s\")",
4137 host_and_ident(FALSE), string_printing(smtp_cmd_buffer));
4144 /* If sender_host_unknown is true, we have got here via the -bs interface,
4145 not called from inetd. Otherwise, we are running an IP connection and the
4146 host address will be set. If the helo name is the primary name of this
4147 host and we haven't done a reverse lookup, force one now. If helo_required
4148 is set, ensure that the HELO name matches the actual host. If helo_verify
4149 is set, do the same check, but softly. */
4151 if (!f.sender_host_unknown)
4153 BOOL old_helo_verified = f.helo_verified;
4154 uschar *p = smtp_cmd_data;
4156 while (*p != 0 && !isspace(*p)) { *p = tolower(*p); p++; }
4159 /* Force a reverse lookup if HELO quoted something in helo_lookup_domains
4160 because otherwise the log can be confusing. */
4162 if ( !sender_host_name
4163 && match_isinlist(sender_helo_name, CUSS &helo_lookup_domains, 0,
4164 &domainlist_anchor, NULL, MCL_DOMAIN, TRUE, NULL) == OK)
4165 (void)host_name_lookup();
4167 /* Rebuild the fullhost info to include the HELO name (and the real name
4168 if it was looked up.) */
4170 host_build_sender_fullhost(); /* Rebuild */
4171 set_process_info("handling%s incoming connection from %s",
4172 tls_in.active.sock >= 0 ? " TLS" : "", host_and_ident(FALSE));
4174 /* Verify if configured. This doesn't give much security, but it does
4175 make some people happy to be able to do it. If helo_required is set,
4176 (host matches helo_verify_hosts) failure forces rejection. If helo_verify
4177 is set (host matches helo_try_verify_hosts), it does not. This is perhaps
4178 now obsolescent, since the verification can now be requested selectively
4181 f.helo_verified = f.helo_verify_failed = sender_helo_dnssec = FALSE;
4182 if (fl.helo_required || fl.helo_verify)
4184 BOOL tempfail = !smtp_verify_helo();
4185 if (!f.helo_verified)
4187 if (fl.helo_required)
4189 smtp_printf("%d %s argument does not match calling host\r\n", FALSE,
4190 tempfail? 451 : 550, hello);
4191 log_write(0, LOG_MAIN|LOG_REJECT, "%srejected \"%s %s\" from %s",
4192 tempfail? "temporarily " : "",
4193 hello, sender_helo_name, host_and_ident(FALSE));
4194 f.helo_verified = old_helo_verified;
4195 break; /* End of HELO/EHLO processing */
4197 HDEBUG(D_all) debug_printf("%s verification failed but host is in "
4198 "helo_try_verify_hosts\n", hello);
4204 /* set up SPF context */
4205 spf_init(sender_helo_name, sender_host_address);
4208 /* Apply an ACL check if one is defined; afterwards, recheck
4209 synchronization in case the client started sending in a delay. */
4212 if ((rc = acl_check(ACL_WHERE_HELO, NULL, acl_smtp_helo,
4213 &user_msg, &log_msg)) != OK)
4215 done = smtp_handle_acl_fail(ACL_WHERE_HELO, rc, user_msg, log_msg);
4216 if (sender_helo_name)
4218 store_free(sender_helo_name);
4219 sender_helo_name = NULL;
4221 host_build_sender_fullhost(); /* Rebuild */
4224 #ifdef EXPERIMENTAL_PIPE_CONNECT
4225 else if (!fl.pipe_connect_acceptable && !check_sync())
4227 else if (!check_sync())
4231 /* Generate an OK reply. The default string includes the ident if present,
4232 and also the IP address if present. Reflecting back the ident is intended
4233 as a deterrent to mail forgers. For maximum efficiency, and also because
4234 some broken systems expect each response to be in a single packet, arrange
4235 that the entire reply is sent in one write(). */
4237 fl.auth_advertised = FALSE;
4238 f.smtp_in_pipelining_advertised = FALSE;
4240 fl.tls_advertised = FALSE;
4241 # ifdef EXPERIMENTAL_REQUIRETLS
4242 fl.requiretls_advertised = FALSE;
4245 fl.dsn_advertised = FALSE;
4247 fl.smtputf8_advertised = FALSE;
4250 smtp_code = US"250 "; /* Default response code plus space*/
4253 g = string_fmt_append(NULL, "%.3s %s Hello %s%s%s",
4255 smtp_active_hostname,
4256 sender_ident ? sender_ident : US"",
4257 sender_ident ? US" at " : US"",
4258 sender_host_name ? sender_host_name : sender_helo_name);
4260 if (sender_host_address)
4261 g = string_fmt_append(g, " [%s]", sender_host_address);
4264 /* A user-supplied EHLO greeting may not contain more than one line. Note
4265 that the code returned by smtp_message_code() includes the terminating
4266 whitespace character. */
4272 smtp_message_code(&smtp_code, &codelen, &user_msg, NULL, TRUE);
4273 s = string_sprintf("%.*s%s", codelen, smtp_code, user_msg);
4274 if ((ss = strpbrk(CS s, "\r\n")) != NULL)
4276 log_write(0, LOG_MAIN|LOG_PANIC, "EHLO/HELO response must not contain "
4277 "newlines: message truncated: %s", string_printing(s));
4280 g = string_cat(NULL, s);
4283 g = string_catn(g, US"\r\n", 2);
4285 /* If we received EHLO, we must create a multiline response which includes
4286 the functions supported. */
4292 /* I'm not entirely happy with this, as an MTA is supposed to check
4293 that it has enough room to accept a message of maximum size before
4294 it sends this. However, there seems little point in not sending it.
4295 The actual size check happens later at MAIL FROM time. By postponing it
4296 till then, VRFY and EXPN can be used after EHLO when space is short. */
4298 if (thismessage_size_limit > 0)
4299 g = string_fmt_append(g, "%.3s-SIZE %d\r\n", smtp_code,
4300 thismessage_size_limit);
4303 g = string_catn(g, smtp_code, 3);
4304 g = string_catn(g, US"-SIZE\r\n", 7);
4307 /* Exim does not do protocol conversion or data conversion. It is 8-bit
4308 clean; if it has an 8-bit character in its hand, it just sends it. It
4309 cannot therefore specify 8BITMIME and remain consistent with the RFCs.
4310 However, some users want this option simply in order to stop MUAs
4311 mangling messages that contain top-bit-set characters. It is therefore
4312 provided as an option. */
4314 if (accept_8bitmime)
4316 g = string_catn(g, smtp_code, 3);
4317 g = string_catn(g, US"-8BITMIME\r\n", 11);
4320 /* Advertise DSN support if configured to do so. */
4321 if (verify_check_host(&dsn_advertise_hosts) != FAIL)
4323 g = string_catn(g, smtp_code, 3);
4324 g = string_catn(g, US"-DSN\r\n", 6);
4325 fl.dsn_advertised = TRUE;
4328 /* Advertise ETRN/VRFY/EXPN if there's are ACL checking whether a host is
4329 permitted to issue them; a check is made when any host actually tries. */
4333 g = string_catn(g, smtp_code, 3);
4334 g = string_catn(g, US"-ETRN\r\n", 7);
4338 g = string_catn(g, smtp_code, 3);
4339 g = string_catn(g, US"-VRFY\r\n", 7);
4343 g = string_catn(g, smtp_code, 3);
4344 g = string_catn(g, US"-EXPN\r\n", 7);
4347 /* Exim is quite happy with pipelining, so let the other end know that
4348 it is safe to use it, unless advertising is disabled. */
4350 if ( f.pipelining_enable
4351 && verify_check_host(&pipelining_advertise_hosts) == OK)
4353 g = string_catn(g, smtp_code, 3);
4354 g = string_catn(g, US"-PIPELINING\r\n", 13);
4355 sync_cmd_limit = NON_SYNC_CMD_PIPELINING;
4356 f.smtp_in_pipelining_advertised = TRUE;
4358 #ifdef EXPERIMENTAL_PIPE_CONNECT
4359 if (fl.pipe_connect_acceptable)
4361 f.smtp_in_early_pipe_advertised = TRUE;
4362 g = string_catn(g, smtp_code, 3);
4363 g = string_catn(g, US"-" EARLY_PIPE_FEATURE_NAME "\r\n", EARLY_PIPE_FEATURE_LEN+3);
4369 /* If any server authentication mechanisms are configured, advertise
4370 them if the current host is in auth_advertise_hosts. The problem with
4371 advertising always is that some clients then require users to
4372 authenticate (and aren't configurable otherwise) even though it may not
4373 be necessary (e.g. if the host is in host_accept_relay).
4375 RFC 2222 states that SASL mechanism names contain only upper case
4376 letters, so output the names in upper case, though we actually recognize
4377 them in either case in the AUTH command. */
4381 && !sender_host_authenticated
4383 && verify_check_host(&auth_advertise_hosts) == OK
4387 for (auth_instance * au = auths; au; au = au->next)
4389 au->advertised = FALSE;
4392 DEBUG(D_auth+D_expand) debug_printf_indent(
4393 "Evaluating advertise_condition for %s athenticator\n",
4395 if ( !au->advertise_condition
4396 || expand_check_condition(au->advertise_condition, au->name,
4403 g = string_catn(g, smtp_code, 3);
4404 g = string_catn(g, US"-AUTH", 5);
4406 fl.auth_advertised = TRUE;
4409 g = string_catn(g, US" ", 1);
4410 g = string_cat (g, au->public_name);
4411 while (++saveptr < g->ptr) g->s[saveptr] = toupper(g->s[saveptr]);
4412 au->advertised = TRUE;
4417 if (!first) g = string_catn(g, US"\r\n", 2);
4420 /* RFC 3030 CHUNKING */
4422 if (verify_check_host(&chunking_advertise_hosts) != FAIL)
4424 g = string_catn(g, smtp_code, 3);
4425 g = string_catn(g, US"-CHUNKING\r\n", 11);
4426 f.chunking_offered = TRUE;
4427 chunking_state = CHUNKING_OFFERED;
4430 /* Advertise TLS (Transport Level Security) aka SSL (Secure Socket Layer)
4431 if it has been included in the binary, and the host matches
4432 tls_advertise_hosts. We must *not* advertise if we are already in a
4433 secure connection. */
4436 if (tls_in.active.sock < 0 &&
4437 verify_check_host(&tls_advertise_hosts) != FAIL)
4439 g = string_catn(g, smtp_code, 3);
4440 g = string_catn(g, US"-STARTTLS\r\n", 11);
4441 fl.tls_advertised = TRUE;
4444 # ifdef EXPERIMENTAL_REQUIRETLS
4445 /* Advertise REQUIRETLS only once we are in a secure connection */
4446 if ( tls_in.active.sock >= 0
4447 && verify_check_host(&tls_advertise_requiretls) != FAIL)
4449 g = string_catn(g, smtp_code, 3);
4450 g = string_catn(g, US"-REQUIRETLS\r\n", 13);
4451 fl.requiretls_advertised = TRUE;
4456 #ifndef DISABLE_PRDR
4457 /* Per Recipient Data Response, draft by Eric A. Hall extending RFC */
4460 g = string_catn(g, smtp_code, 3);
4461 g = string_catn(g, US"-PRDR\r\n", 7);
4466 if ( accept_8bitmime
4467 && verify_check_host(&smtputf8_advertise_hosts) != FAIL)
4469 g = string_catn(g, smtp_code, 3);
4470 g = string_catn(g, US"-SMTPUTF8\r\n", 11);
4471 fl.smtputf8_advertised = TRUE;
4475 /* Finish off the multiline reply with one that is always available. */
4477 g = string_catn(g, smtp_code, 3);
4478 g = string_catn(g, US" HELP\r\n", 7);
4481 /* Terminate the string (for debug), write it, and note that HELO/EHLO
4485 if (tls_in.active.sock >= 0)
4486 (void)tls_write(NULL, g->s, g->ptr,
4487 # ifdef EXPERIMENTAL_PIPE_CONNECT
4488 fl.pipe_connect_acceptable && pipeline_connect_sends());
4496 int i = fwrite(g->s, 1, g->ptr, smtp_out); i = i; /* compiler quietening */
4502 (void) string_from_gstring(g);
4503 while ((cr = Ustrchr(g->s, '\r')) != NULL) /* lose CRs */
4504 memmove(cr, cr + 1, (g->ptr--) - (cr - g->s));
4505 debug_printf("SMTP>> %s", g->s);
4507 fl.helo_seen = TRUE;
4509 /* Reset the protocol and the state, abandoning any previous message. */
4511 (sender_host_address ? protocols : protocols_local)
4513 ? pextend + (sender_host_authenticated ? pauthed : 0)
4515 + (tls_in.active.sock >= 0 ? pcrpted : 0)
4517 cancel_cutthrough_connection(TRUE, US"sent EHLO response");
4518 smtp_reset(reset_point);
4520 break; /* HELO/EHLO */
4523 /* The MAIL command requires an address as an operand. All we do
4524 here is to parse it for syntactic correctness. The form "<>" is
4525 a special case which converts into an empty string. The start/end
4526 pointers in the original are not used further for this address, as
4527 it is the canonical extracted address which is all that is kept. */
4531 smtp_mailcmd_count++; /* Count for limit and ratelimit */
4532 was_rej_mail = TRUE; /* Reset if accepted */
4533 env_mail_type_t * mail_args; /* Sanity check & validate args */
4535 if (fl.helo_required && !fl.helo_seen)
4537 smtp_printf("503 HELO or EHLO required\r\n", FALSE);
4538 log_write(0, LOG_MAIN|LOG_REJECT, "rejected MAIL from %s: no "
4539 "HELO/EHLO given", host_and_ident(FALSE));
4545 done = synprot_error(L_smtp_protocol_error, 503, NULL,
4546 US"sender already given");
4550 if (!*smtp_cmd_data)
4552 done = synprot_error(L_smtp_protocol_error, 501, NULL,
4553 US"MAIL must have an address operand");
4557 /* Check to see if the limit for messages per connection would be
4558 exceeded by accepting further messages. */
4560 if (smtp_accept_max_per_connection > 0 &&
4561 smtp_mailcmd_count > smtp_accept_max_per_connection)
4563 smtp_printf("421 too many messages in this connection\r\n", FALSE);
4564 log_write(0, LOG_MAIN|LOG_REJECT, "rejected MAIL command %s: too many "
4565 "messages in one connection", host_and_ident(TRUE));
4569 /* Reset for start of message - even if this is going to fail, we
4570 obviously need to throw away any previous data. */
4572 cancel_cutthrough_connection(TRUE, US"MAIL received");
4573 smtp_reset(reset_point);
4575 sender_data = recipient_data = NULL;
4577 /* Loop, checking for ESMTP additions to the MAIL FROM command. */
4579 if (fl.esmtp) for(;;)
4581 uschar *name, *value, *end;
4582 unsigned long int size;
4583 BOOL arg_error = FALSE;
4585 if (!extract_option(&name, &value)) break;
4587 for (mail_args = env_mail_type_list;
4588 mail_args->value != ENV_MAIL_OPT_NULL;
4591 if (strcmpic(name, mail_args->name) == 0)
4593 if (mail_args->need_value && strcmpic(value, US"") == 0)
4596 switch(mail_args->value)
4598 /* Handle SIZE= by reading the value. We don't do the check till later,
4599 in order to be able to log the sender address on failure. */
4600 case ENV_MAIL_OPT_SIZE:
4601 if (((size = Ustrtoul(value, &end, 10)), *end == 0))
4603 if ((size == ULONG_MAX && errno == ERANGE) || size > INT_MAX)
4605 message_size = (int)size;
4611 /* If this session was initiated with EHLO and accept_8bitmime is set,
4612 Exim will have indicated that it supports the BODY=8BITMIME option. In
4613 fact, it does not support this according to the RFCs, in that it does not
4614 take any special action for forwarding messages containing 8-bit
4615 characters. That is why accept_8bitmime is not the default setting, but
4616 some sites want the action that is provided. We recognize both "8BITMIME"
4617 and "7BIT" as body types, but take no action. */
4618 case ENV_MAIL_OPT_BODY:
4619 if (accept_8bitmime) {
4620 if (strcmpic(value, US"8BITMIME") == 0)
4622 else if (strcmpic(value, US"7BIT") == 0)
4627 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4628 US"invalid data for BODY");
4631 DEBUG(D_receive) debug_printf("8BITMIME: %d\n", body_8bitmime);
4637 /* Handle the two DSN options, but only if configured to do so (which
4638 will have caused "DSN" to be given in the EHLO response). The code itself
4639 is included only if configured in at build time. */
4641 case ENV_MAIL_OPT_RET:
4642 if (fl.dsn_advertised)
4644 /* Check if RET has already been set */
4647 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4648 US"RET can be specified once only");
4651 dsn_ret = strcmpic(value, US"HDRS") == 0
4653 : strcmpic(value, US"FULL") == 0
4656 DEBUG(D_receive) debug_printf("DSN_RET: %d\n", dsn_ret);
4657 /* Check for invalid invalid value, and exit with error */
4660 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4661 US"Value for RET is invalid");
4666 case ENV_MAIL_OPT_ENVID:
4667 if (fl.dsn_advertised)
4669 /* Check if the dsn envid has been already set */
4672 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4673 US"ENVID can be specified once only");
4676 dsn_envid = string_copy(value);
4677 DEBUG(D_receive) debug_printf("DSN_ENVID: %s\n", dsn_envid);
4681 /* Handle the AUTH extension. If the value given is not "<>" and either
4682 the ACL says "yes" or there is no ACL but the sending host is
4683 authenticated, we set it up as the authenticated sender. However, if the
4684 authenticator set a condition to be tested, we ignore AUTH on MAIL unless
4685 the condition is met. The value of AUTH is an xtext, which means that +,
4686 = and cntrl chars are coded in hex; however "<>" is unaffected by this
4688 case ENV_MAIL_OPT_AUTH:
4689 if (Ustrcmp(value, "<>") != 0)
4694 if (auth_xtextdecode(value, &authenticated_sender) < 0)
4696 /* Put back terminator overrides for error message */
4699 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4700 US"invalid data for AUTH");
4703 if (!acl_smtp_mailauth)
4705 ignore_msg = US"client not authenticated";
4706 rc = sender_host_authenticated ? OK : FAIL;
4710 ignore_msg = US"rejected by ACL";
4711 rc = acl_check(ACL_WHERE_MAILAUTH, NULL, acl_smtp_mailauth,
4712 &user_msg, &log_msg);
4718 if (authenticated_by == NULL ||
4719 authenticated_by->mail_auth_condition == NULL ||
4720 expand_check_condition(authenticated_by->mail_auth_condition,
4721 authenticated_by->name, US"authenticator"))
4722 break; /* Accept the AUTH */
4724 ignore_msg = US"server_mail_auth_condition failed";
4725 if (authenticated_id != NULL)
4726 ignore_msg = string_sprintf("%s: authenticated ID=\"%s\"",
4727 ignore_msg, authenticated_id);
4732 authenticated_sender = NULL;
4733 log_write(0, LOG_MAIN, "ignoring AUTH=%s from %s (%s)",
4734 value, host_and_ident(TRUE), ignore_msg);
4737 /* Should only get DEFER or ERROR here. Put back terminator
4738 overrides for error message */
4743 (void)smtp_handle_acl_fail(ACL_WHERE_MAILAUTH, rc, user_msg,
4750 #ifndef DISABLE_PRDR
4751 case ENV_MAIL_OPT_PRDR:
4753 prdr_requested = TRUE;
4758 case ENV_MAIL_OPT_UTF8:
4759 if (!fl.smtputf8_advertised)
4761 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4762 US"SMTPUTF8 used when not advertised");
4766 DEBUG(D_receive) debug_printf("smtputf8 requested\n");
4767 message_smtputf8 = allow_utf8_domains = TRUE;
4768 if (Ustrncmp(received_protocol, US"utf8", 4) != 0)
4770 int old_pool = store_pool;
4771 store_pool = POOL_PERM;
4772 received_protocol = string_sprintf("utf8%s", received_protocol);
4773 store_pool = old_pool;
4778 #if defined(SUPPORT_TLS) && defined(EXPERIMENTAL_REQUIRETLS)
4779 case ENV_MAIL_OPT_REQTLS:
4783 if (!fl.requiretls_advertised)
4785 done = synprot_error(L_smtp_syntax_error, 555, NULL,
4786 US"unadvertised MAIL option: REQUIRETLS");
4790 DEBUG(D_receive) debug_printf("requiretls requested\n");
4791 tls_requiretls = REQUIRETLS_MSG;
4793 r = string_copy_malloc(received_protocol);
4794 if ((t = Ustrrchr(r, 's'))) *t = 'S';
4795 received_protocol = r;
4800 /* No valid option. Stick back the terminator characters and break
4801 the loop. Do the name-terminator second as extract_option sets
4802 value==name when it found no equal-sign.
4803 An error for a malformed address will occur. */
4804 case ENV_MAIL_OPT_NULL:
4812 /* Break out of for loop if switch() had bad argument or
4813 when start of the email address is reached */
4814 if (arg_error) break;
4817 #if defined(SUPPORT_TLS) && defined(EXPERIMENTAL_REQUIRETLS)
4818 if (tls_requiretls & REQUIRETLS_MSG)
4820 /* Ensure headers-only bounces whether a RET option was given or not. */
4822 DEBUG(D_receive) if (dsn_ret == dsn_ret_full)
4823 debug_printf("requiretls override: dsn_ret_full -> dsn_ret_hdrs\n");
4824 dsn_ret = dsn_ret_hdrs;
4828 /* If we have passed the threshold for rate limiting, apply the current
4829 delay, and update it for next time, provided this is a limited host. */
4831 if (smtp_mailcmd_count > smtp_rlm_threshold &&
4832 verify_check_host(&smtp_ratelimit_hosts) == OK)
4834 DEBUG(D_receive) debug_printf("rate limit MAIL: delay %.3g sec\n",
4835 smtp_delay_mail/1000.0);
4836 millisleep((int)smtp_delay_mail);
4837 smtp_delay_mail *= smtp_rlm_factor;
4838 if (smtp_delay_mail > (double)smtp_rlm_limit)
4839 smtp_delay_mail = (double)smtp_rlm_limit;
4842 /* Now extract the address, first applying any SMTP-time rewriting. The
4843 TRUE flag allows "<>" as a sender address. */
4845 raw_sender = rewrite_existflags & rewrite_smtp
4846 ? rewrite_one(smtp_cmd_data, rewrite_smtp, NULL, FALSE, US"",
4847 global_rewrite_rules)
4851 parse_extract_address(raw_sender, &errmess, &start, &end, &sender_domain,
4856 done = synprot_error(L_smtp_syntax_error, 501, smtp_cmd_data, errmess);
4860 sender_address = raw_sender;
4862 /* If there is a configured size limit for mail, check that this message
4863 doesn't exceed it. The check is postponed to this point so that the sender
4866 if (thismessage_size_limit > 0 && message_size > thismessage_size_limit)
4868 smtp_printf("552 Message size exceeds maximum permitted\r\n", FALSE);
4869 log_write(L_size_reject,
4870 LOG_MAIN|LOG_REJECT, "rejected MAIL FROM:<%s> %s: "
4871 "message too big: size%s=%d max=%d",
4873 host_and_ident(TRUE),
4874 (message_size == INT_MAX)? ">" : "",
4876 thismessage_size_limit);
4877 sender_address = NULL;
4881 /* Check there is enough space on the disk unless configured not to.
4882 When smtp_check_spool_space is set, the check is for thismessage_size_limit
4883 plus the current message - i.e. we accept the message only if it won't
4884 reduce the space below the threshold. Add 5000 to the size to allow for
4885 overheads such as the Received: line and storing of recipients, etc.
4886 By putting the check here, even when SIZE is not given, it allow VRFY
4887 and EXPN etc. to be used when space is short. */
4889 if (!receive_check_fs(
4890 (smtp_check_spool_space && message_size >= 0)?
4891 message_size + 5000 : 0))
4893 smtp_printf("452 Space shortage, please try later\r\n", FALSE);
4894 sender_address = NULL;
4898 /* If sender_address is unqualified, reject it, unless this is a locally
4899 generated message, or the sending host or net is permitted to send
4900 unqualified addresses - typically local machines behaving as MUAs -
4901 in which case just qualify the address. The flag is set above at the start
4902 of the SMTP connection. */
4904 if (!sender_domain && *sender_address)
4905 if (f.allow_unqualified_sender)
4907 sender_domain = Ustrlen(sender_address) + 1;
4908 sender_address = rewrite_address_qualify(sender_address, FALSE);
4909 DEBUG(D_receive) debug_printf("unqualified address %s accepted\n",
4914 smtp_printf("501 %s: sender address must contain a domain\r\n", FALSE,
4916 log_write(L_smtp_syntax_error,
4917 LOG_MAIN|LOG_REJECT,
4918 "unqualified sender rejected: <%s> %s%s",
4920 host_and_ident(TRUE),
4922 sender_address = NULL;
4926 /* Apply an ACL check if one is defined, before responding. Afterwards,
4927 when pipelining is not advertised, do another sync check in case the ACL
4928 delayed and the client started sending in the meantime. */
4932 rc = acl_check(ACL_WHERE_MAIL, NULL, acl_smtp_mail, &user_msg, &log_msg);
4933 if (rc == OK && !f.smtp_in_pipelining_advertised && !check_sync())
4939 if (rc == OK || rc == DISCARD)
4941 BOOL more = pipeline_response();
4944 smtp_printf("%s%s%s", more, US"250 OK",
4945 #ifndef DISABLE_PRDR
4946 prdr_requested ? US", PRDR Requested" : US"",
4953 #ifndef DISABLE_PRDR
4955 user_msg = string_sprintf("%s%s", user_msg, US", PRDR Requested");
4957 smtp_user_msg(US"250", user_msg);
4959 smtp_delay_rcpt = smtp_rlr_base;
4960 f.recipients_discarded = (rc == DISCARD);
4961 was_rej_mail = FALSE;
4965 done = smtp_handle_acl_fail(ACL_WHERE_MAIL, rc, user_msg, log_msg);
4966 sender_address = NULL;
4971 /* The RCPT command requires an address as an operand. There may be any
4972 number of RCPT commands, specifying multiple recipients. We build them all
4973 into a data structure. The start/end values given by parse_extract_address
4974 are not used, as we keep only the extracted address. */
4979 was_rcpt = fl.rcpt_in_progress = TRUE;
4981 /* There must be a sender address; if the sender was rejected and
4982 pipelining was advertised, we assume the client was pipelining, and do not
4983 count this as a protocol error. Reset was_rej_mail so that further RCPTs
4984 get the same treatment. */
4986 if (sender_address == NULL)
4988 if (f.smtp_in_pipelining_advertised && last_was_rej_mail)
4990 smtp_printf("503 sender not yet given\r\n", FALSE);
4991 was_rej_mail = TRUE;
4995 done = synprot_error(L_smtp_protocol_error, 503, NULL,
4996 US"sender not yet given");
4997 was_rcpt = FALSE; /* Not a valid RCPT */
5003 /* Check for an operand */
5005 if (smtp_cmd_data[0] == 0)
5007 done = synprot_error(L_smtp_syntax_error, 501, NULL,
5008 US"RCPT must have an address operand");
5013 /* Set the DSN flags orcpt and dsn_flags from the session*/
5017 if (fl.esmtp) for(;;)
5019 uschar *name, *value;
5021 if (!extract_option(&name, &value))
5024 if (fl.dsn_advertised && strcmpic(name, US"ORCPT") == 0)
5026 /* Check whether orcpt has been already set */
5029 done = synprot_error(L_smtp_syntax_error, 501, NULL,
5030 US"ORCPT can be specified once only");
5033 orcpt = string_copy(value);
5034 DEBUG(D_receive) debug_printf("DSN orcpt: %s\n", orcpt);
5037 else if (fl.dsn_advertised && strcmpic(name, US"NOTIFY") == 0)
5039 /* Check if the notify flags have been already set */
5042 done = synprot_error(L_smtp_syntax_error, 501, NULL,
5043 US"NOTIFY can be specified once only");
5046 if (strcmpic(value, US"NEVER") == 0)
5047 dsn_flags |= rf_notify_never;
5054 while (*pp != 0 && *pp != ',') pp++;
5055 if (*pp == ',') *pp++ = 0;
5056 if (strcmpic(p, US"SUCCESS") == 0)
5058 DEBUG(D_receive) debug_printf("DSN: Setting notify success\n");
5059 dsn_flags |= rf_notify_success;
5061 else if (strcmpic(p, US"FAILURE") == 0)
5063 DEBUG(D_receive) debug_printf("DSN: Setting notify failure\n");
5064 dsn_flags |= rf_notify_failure;
5066 else if (strcmpic(p, US"DELAY") == 0)
5068 DEBUG(D_receive) debug_printf("DSN: Setting notify delay\n");
5069 dsn_flags |= rf_notify_delay;
5073 /* Catch any strange values */
5074 done = synprot_error(L_smtp_syntax_error, 501, NULL,
5075 US"Invalid value for NOTIFY parameter");
5080 DEBUG(D_receive) debug_printf("DSN Flags: %x\n", dsn_flags);
5084 /* Unknown option. Stick back the terminator characters and break
5085 the loop. An error for a malformed address will occur. */
5089 DEBUG(D_receive) debug_printf("Invalid RCPT option: %s : %s\n", name, value);
5096 /* Apply SMTP rewriting then extract the working address. Don't allow "<>"
5097 as a recipient address */
5099 recipient = rewrite_existflags & rewrite_smtp
5100 ? rewrite_one(smtp_cmd_data, rewrite_smtp, NULL, FALSE, US"",
5101 global_rewrite_rules)
5104 if (!(recipient = parse_extract_address(recipient, &errmess, &start, &end,
5105 &recipient_domain, FALSE)))
5107 done = synprot_error(L_smtp_syntax_error, 501, smtp_cmd_data, errmess);
5112 /* If the recipient address is unqualified, reject it, unless this is a
5113 locally generated message. However, unqualified addresses are permitted
5114 from a configured list of hosts and nets - typically when behaving as
5115 MUAs rather than MTAs. Sad that SMTP is used for both types of traffic,
5116 really. The flag is set at the start of the SMTP connection.
5118 RFC 1123 talks about supporting "the reserved mailbox postmaster"; I always
5119 assumed this meant "reserved local part", but the revision of RFC 821 and
5120 friends now makes it absolutely clear that it means *mailbox*. Consequently
5121 we must always qualify this address, regardless. */
5123 if (!recipient_domain)
5124 if (!(recipient_domain = qualify_recipient(&recipient, smtp_cmd_data,
5131 /* Check maximum allowed */
5133 if (rcpt_count > recipients_max && recipients_max > 0)
5135 if (recipients_max_reject)
5138 smtp_printf("552 too many recipients\r\n", FALSE);
5140 log_write(0, LOG_MAIN|LOG_REJECT, "too many recipients: message "
5141 "rejected: sender=<%s> %s", sender_address, host_and_ident(TRUE));
5146 smtp_printf("452 too many recipients\r\n", FALSE);
5148 log_write(0, LOG_MAIN|LOG_REJECT, "too many recipients: excess "
5149 "temporarily rejected: sender=<%s> %s", sender_address,
5150 host_and_ident(TRUE));
5157 /* If we have passed the threshold for rate limiting, apply the current
5158 delay, and update it for next time, provided this is a limited host. */
5160 if (rcpt_count > smtp_rlr_threshold &&
5161 verify_check_host(&smtp_ratelimit_hosts) == OK)
5163 DEBUG(D_receive) debug_printf("rate limit RCPT: delay %.3g sec\n",
5164 smtp_delay_rcpt/1000.0);
5165 millisleep((int)smtp_delay_rcpt);
5166 smtp_delay_rcpt *= smtp_rlr_factor;
5167 if (smtp_delay_rcpt > (double)smtp_rlr_limit)
5168 smtp_delay_rcpt = (double)smtp_rlr_limit;
5171 /* If the MAIL ACL discarded all the recipients, we bypass ACL checking
5172 for them. Otherwise, check the access control list for this recipient. As
5173 there may be a delay in this, re-check for a synchronization error
5174 afterwards, unless pipelining was advertised. */
5176 if (f.recipients_discarded)
5179 if ( (rc = acl_check(ACL_WHERE_RCPT, recipient, acl_smtp_rcpt, &user_msg,
5181 && !f.smtp_in_pipelining_advertised && !check_sync())
5184 /* The ACL was happy */
5188 BOOL more = pipeline_response();
5191 smtp_user_msg(US"250", user_msg);
5193 smtp_printf("250 Accepted\r\n", more);
5194 receive_add_recipient(recipient, -1);
5196 /* Set the dsn flags in the recipients_list */
5197 recipients_list[recipients_count-1].orcpt = orcpt;
5198 recipients_list[recipients_count-1].dsn_flags = dsn_flags;
5200 DEBUG(D_receive) debug_printf("DSN: orcpt: %s flags: %d\n",
5201 recipients_list[recipients_count-1].orcpt,
5202 recipients_list[recipients_count-1].dsn_flags);
5205 /* The recipient was discarded */
5207 else if (rc == DISCARD)
5210 smtp_user_msg(US"250", user_msg);
5212 smtp_printf("250 Accepted\r\n", FALSE);
5215 log_write(0, LOG_MAIN|LOG_REJECT, "%s F=<%s> RCPT %s: "
5216 "discarded by %s ACL%s%s", host_and_ident(TRUE),
5217 sender_address_unrewritten? sender_address_unrewritten : sender_address,
5218 smtp_cmd_argument, f.recipients_discarded? "MAIL" : "RCPT",
5219 log_msg ? US": " : US"", log_msg ? log_msg : US"");
5222 /* Either the ACL failed the address, or it was deferred. */
5226 if (rc == FAIL) rcpt_fail_count++; else rcpt_defer_count++;
5227 done = smtp_handle_acl_fail(ACL_WHERE_RCPT, rc, user_msg, log_msg);
5232 /* The DATA command is legal only if it follows successful MAIL FROM
5233 and RCPT TO commands. However, if pipelining is advertised, a bad DATA is
5234 not counted as a protocol error if it follows RCPT (which must have been
5235 rejected if there are no recipients.) This function is complete when a
5236 valid DATA command is encountered.
5238 Note concerning the code used: RFC 2821 says this:
5240 - If there was no MAIL, or no RCPT, command, or all such commands
5241 were rejected, the server MAY return a "command out of sequence"
5242 (503) or "no valid recipients" (554) reply in response to the
5245 The example in the pipelining RFC 2920 uses 554, but I use 503 here
5246 because it is the same whether pipelining is in use or not.
5248 If all the RCPT commands that precede DATA provoked the same error message
5249 (often indicating some kind of system error), it is helpful to include it
5250 with the DATA rejection (an idea suggested by Tony Finch). */
5257 if (chunking_state != CHUNKING_OFFERED)
5259 done = synprot_error(L_smtp_protocol_error, 503, NULL,
5260 US"BDAT command used when CHUNKING not advertised");
5264 /* grab size, endmarker */
5266 if (sscanf(CS smtp_cmd_data, "%u %n", &chunking_datasize, &n) < 1)
5268 done = synprot_error(L_smtp_protocol_error, 501, NULL,
5269 US"missing size for BDAT command");
5272 chunking_state = strcmpic(smtp_cmd_data+n, US"LAST") == 0
5273 ? CHUNKING_LAST : CHUNKING_ACTIVE;
5274 chunking_data_left = chunking_datasize;
5275 DEBUG(D_receive) debug_printf("chunking state %d, %d bytes\n",
5276 (int)chunking_state, chunking_data_left);
5278 /* push the current receive_* function on the "stack", and
5279 replace them by bdat_getc(), which in turn will use the lwr_receive_*
5280 functions to do the dirty work. */
5281 lwr_receive_getc = receive_getc;
5282 lwr_receive_getbuf = receive_getbuf;
5283 lwr_receive_ungetc = receive_ungetc;
5285 receive_getc = bdat_getc;
5286 receive_ungetc = bdat_ungetc;
5297 DATA_BDAT: /* Common code for DATA and BDAT */
5298 #ifdef EXPERIMENTAL_PIPE_CONNECT
5299 fl.pipe_connect_acceptable = FALSE;
5301 if (!discarded && recipients_count <= 0)
5303 if (fl.rcpt_smtp_response_same && rcpt_smtp_response != NULL)
5305 uschar *code = US"503";
5306 int len = Ustrlen(rcpt_smtp_response);
5307 smtp_respond(code, 3, FALSE, US"All RCPT commands were rejected with "
5309 /* Responses from smtp_printf() will have \r\n on the end */
5310 if (len > 2 && rcpt_smtp_response[len-2] == '\r')
5311 rcpt_smtp_response[len-2] = 0;
5312 smtp_respond(code, 3, FALSE, rcpt_smtp_response);
5314 if (f.smtp_in_pipelining_advertised && last_was_rcpt)
5315 smtp_printf("503 Valid RCPT command must precede %s\r\n", FALSE,
5316 smtp_names[smtp_connection_had[smtp_ch_index-1]]);
5318 done = synprot_error(L_smtp_protocol_error, 503, NULL,
5319 smtp_connection_had[smtp_ch_index-1] == SCH_DATA
5320 ? US"valid RCPT command must precede DATA"
5321 : US"valid RCPT command must precede BDAT");
5323 if (chunking_state > CHUNKING_OFFERED)
5328 if (toomany && recipients_max_reject)
5330 sender_address = NULL; /* This will allow a new MAIL without RSET */
5331 sender_address_unrewritten = NULL;
5332 smtp_printf("554 Too many recipients\r\n", FALSE);
5336 if (chunking_state > CHUNKING_OFFERED)
5337 rc = OK; /* No predata ACL or go-ahead output for BDAT */
5340 /* If there is an ACL, re-check the synchronization afterwards, since the
5341 ACL may have delayed. To handle cutthrough delivery enforce a dummy call
5342 to get the DATA command sent. */
5344 if (acl_smtp_predata == NULL && cutthrough.cctx.sock < 0)
5348 uschar * acl = acl_smtp_predata ? acl_smtp_predata : US"accept";
5349 f.enable_dollar_recipients = TRUE;
5350 rc = acl_check(ACL_WHERE_PREDATA, NULL, acl, &user_msg,
5352 f.enable_dollar_recipients = FALSE;
5353 if (rc == OK && !check_sync())
5357 { /* Either the ACL failed the address, or it was deferred. */
5358 done = smtp_handle_acl_fail(ACL_WHERE_PREDATA, rc, user_msg, log_msg);
5364 smtp_user_msg(US"354", user_msg);
5367 "354 Enter message, ending with \".\" on a line by itself\r\n", FALSE);
5371 if (smtp_in) /* all ACKs needed to ramp window up for bulk data */
5372 (void) setsockopt(fileno(smtp_in), IPPROTO_TCP, TCP_QUICKACK,
5373 US &on, sizeof(on));
5376 message_ended = END_NOTENDED; /* Indicate in middle of data */
5387 if (!(address = parse_extract_address(smtp_cmd_data, &errmess,
5388 &start, &end, &recipient_domain, FALSE)))
5390 smtp_printf("501 %s\r\n", FALSE, errmess);
5394 if (!recipient_domain)
5395 if (!(recipient_domain = qualify_recipient(&address, smtp_cmd_data,
5399 if ((rc = acl_check(ACL_WHERE_VRFY, address, acl_smtp_vrfy,
5400 &user_msg, &log_msg)) != OK)
5401 done = smtp_handle_acl_fail(ACL_WHERE_VRFY, rc, user_msg, log_msg);
5405 address_item * addr = deliver_make_addr(address, FALSE);
5407 switch(verify_address(addr, NULL, vopt_is_recipient | vopt_qualify, -1,
5408 -1, -1, NULL, NULL, NULL))
5411 s = string_sprintf("250 <%s> is deliverable", address);
5415 s = (addr->user_message != NULL)?
5416 string_sprintf("451 <%s> %s", address, addr->user_message) :
5417 string_sprintf("451 Cannot resolve <%s> at this time", address);
5421 s = (addr->user_message != NULL)?
5422 string_sprintf("550 <%s> %s", address, addr->user_message) :
5423 string_sprintf("550 <%s> is not deliverable", address);
5424 log_write(0, LOG_MAIN, "VRFY failed for %s %s",
5425 smtp_cmd_argument, host_and_ident(TRUE));
5429 smtp_printf("%s\r\n", FALSE, s);
5437 rc = acl_check(ACL_WHERE_EXPN, NULL, acl_smtp_expn, &user_msg, &log_msg);
5439 done = smtp_handle_acl_fail(ACL_WHERE_EXPN, rc, user_msg, log_msg);
5442 BOOL save_log_testing_mode = f.log_testing_mode;
5443 f.address_test_mode = f.log_testing_mode = TRUE;
5444 (void) verify_address(deliver_make_addr(smtp_cmd_data, FALSE),
5445 smtp_out, vopt_is_recipient | vopt_qualify | vopt_expn, -1, -1, -1,
5447 f.address_test_mode = FALSE;
5448 f.log_testing_mode = save_log_testing_mode; /* true for -bh */
5457 if (!fl.tls_advertised)
5459 done = synprot_error(L_smtp_protocol_error, 503, NULL,
5460 US"STARTTLS command used when not advertised");
5464 /* Apply an ACL check if one is defined */
5466 if ( acl_smtp_starttls
5467 && (rc = acl_check(ACL_WHERE_STARTTLS, NULL, acl_smtp_starttls,
5468 &user_msg, &log_msg)) != OK
5471 done = smtp_handle_acl_fail(ACL_WHERE_STARTTLS, rc, user_msg, log_msg);
5475 /* RFC 2487 is not clear on when this command may be sent, though it
5476 does state that all information previously obtained from the client
5477 must be discarded if a TLS session is started. It seems reasonable to
5478 do an implied RSET when STARTTLS is received. */
5480 incomplete_transaction_log(US"STARTTLS");
5481 cancel_cutthrough_connection(TRUE, US"STARTTLS received");
5482 smtp_reset(reset_point);
5484 cmd_list[CMD_LIST_STARTTLS].is_mail_cmd = FALSE;
5486 /* There's an attack where more data is read in past the STARTTLS command
5487 before TLS is negotiated, then assumed to be part of the secure session
5488 when used afterwards; we use segregated input buffers, so are not
5489 vulnerable, but we want to note when it happens and, for sheer paranoia,
5490 ensure that the buffer is "wiped".
5491 Pipelining sync checks will normally have protected us too, unless disabled
5492 by configuration. */
5494 if (receive_smtp_buffered())
5497 debug_printf("Non-empty input buffer after STARTTLS; naive attack?\n");
5498 if (tls_in.active.sock < 0)
5499 smtp_inend = smtp_inptr = smtp_inbuffer;
5500 /* and if TLS is already active, tls_server_start() should fail */
5503 /* There is nothing we value in the input buffer and if TLS is successfully
5504 negotiated, we won't use this buffer again; if TLS fails, we'll just read
5505 fresh content into it. The buffer contains arbitrary content from an
5506 untrusted remote source; eg: NOOP <shellcode>\r\nSTARTTLS\r\n
5507 It seems safest to just wipe away the content rather than leave it as a
5508 target to jump to. */
5510 memset(smtp_inbuffer, 0, IN_BUFFER_SIZE);
5512 /* Attempt to start up a TLS session, and if successful, discard all
5513 knowledge that was obtained previously. At least, that's what the RFC says,
5514 and that's what happens by default. However, in order to work round YAEB,
5515 there is an option to remember the esmtp state. Sigh.
5517 We must allow for an extra EHLO command and an extra AUTH command after
5518 STARTTLS that don't add to the nonmail command count. */
5521 if ((rc = tls_server_start(tls_require_ciphers, &s)) == OK)
5523 if (!tls_remember_esmtp)
5524 fl.helo_seen = fl.esmtp = fl.auth_advertised = f.smtp_in_pipelining_advertised = FALSE;
5525 cmd_list[CMD_LIST_EHLO].is_mail_cmd = TRUE;
5526 cmd_list[CMD_LIST_AUTH].is_mail_cmd = TRUE;
5527 cmd_list[CMD_LIST_TLS_AUTH].is_mail_cmd = TRUE;
5528 if (sender_helo_name)
5530 store_free(sender_helo_name);
5531 sender_helo_name = NULL;
5532 host_build_sender_fullhost(); /* Rebuild */
5533 set_process_info("handling incoming TLS connection from %s",
5534 host_and_ident(FALSE));
5537 (sender_host_address ? protocols : protocols_local)
5539 ? pextend + (sender_host_authenticated ? pauthed : 0)
5541 + (tls_in.active.sock >= 0 ? pcrpted : 0)
5544 sender_host_auth_pubname = sender_host_authenticated = NULL;
5545 authenticated_id = NULL;
5546 sync_cmd_limit = NON_SYNC_CMD_NON_PIPELINING;
5547 DEBUG(D_tls) debug_printf("TLS active\n");
5548 break; /* Successful STARTTLS */
5551 (void) smtp_log_tls_fail(s);
5553 /* Some local configuration problem was discovered before actually trying
5554 to do a TLS handshake; give a temporary error. */
5558 smtp_printf("454 TLS currently unavailable\r\n", FALSE);
5562 /* Hard failure. Reject everything except QUIT or closed connection. One
5563 cause for failure is a nested STARTTLS, in which case tls_in.active remains
5564 set, but we must still reject all incoming commands. Another is a handshake
5565 failure - and there may some encrypted data still in the pipe to us, which we
5566 see as garbage commands. */
5568 DEBUG(D_tls) debug_printf("TLS failed to start\n");
5569 while (done <= 0) switch(smtp_read_command(FALSE, GETC_BUFFER_UNLIMITED))
5572 log_write(L_smtp_connection, LOG_MAIN, "%s closed by EOF",
5573 smtp_get_connection_info());
5574 smtp_notquit_exit(US"tls-failed", NULL, NULL);
5578 /* It is perhaps arguable as to which exit ACL should be called here,
5579 but as it is probably a situation that almost never arises, it
5580 probably doesn't matter. We choose to call the real QUIT ACL, which in
5581 some sense is perhaps "right". */
5586 && ((rc = acl_check(ACL_WHERE_QUIT, NULL, acl_smtp_quit, &user_msg,
5587 &log_msg)) == ERROR))
5588 log_write(0, LOG_MAIN|LOG_PANIC, "ACL for QUIT returned ERROR: %s",
5591 smtp_respond(US"221", 3, TRUE, user_msg);
5593 smtp_printf("221 %s closing connection\r\n", FALSE, smtp_active_hostname);
5594 log_write(L_smtp_connection, LOG_MAIN, "%s closed by QUIT",
5595 smtp_get_connection_info());
5600 smtp_printf("554 Security failure\r\n", FALSE);
5603 tls_close(NULL, TLS_SHUTDOWN_NOWAIT);
5608 /* The ACL for QUIT is provided for gathering statistical information or
5609 similar; it does not affect the response code, but it can supply a custom
5613 smtp_quit_handler(&user_msg, &log_msg);
5619 smtp_rset_handler();
5620 cancel_cutthrough_connection(TRUE, US"RSET received");
5621 smtp_reset(reset_point);
5628 smtp_printf("250 OK\r\n", FALSE);
5632 /* Show ETRN/EXPN/VRFY if there's an ACL for checking hosts; if actually
5633 used, a check will be done for permitted hosts. Show STARTTLS only if not
5634 already in a TLS session and if it would be advertised in the EHLO
5639 smtp_printf("214-Commands supported:\r\n", TRUE);
5643 Ustrcat(buffer, " AUTH");
5645 if (tls_in.active.sock < 0 &&
5646 verify_check_host(&tls_advertise_hosts) != FAIL)
5647 Ustrcat(buffer, " STARTTLS");
5649 Ustrcat(buffer, " HELO EHLO MAIL RCPT DATA BDAT");
5650 Ustrcat(buffer, " NOOP QUIT RSET HELP");
5651 if (acl_smtp_etrn != NULL) Ustrcat(buffer, " ETRN");
5652 if (acl_smtp_expn != NULL) Ustrcat(buffer, " EXPN");
5653 if (acl_smtp_vrfy != NULL) Ustrcat(buffer, " VRFY");
5654 smtp_printf("214%s\r\n", FALSE, buffer);
5660 incomplete_transaction_log(US"connection lost");
5661 smtp_notquit_exit(US"connection-lost", US"421",
5662 US"%s lost input connection", smtp_active_hostname);
5664 /* Don't log by default unless in the middle of a message, as some mailers
5665 just drop the call rather than sending QUIT, and it clutters up the logs.
5668 if (sender_address || recipients_count > 0)
5669 log_write(L_lost_incoming_connection, LOG_MAIN,
5670 "unexpected %s while reading SMTP command from %s%s%s D=%s",
5671 f.sender_host_unknown ? "EOF" : "disconnection",
5672 f.tcp_in_fastopen_logged
5675 ? f.tcp_in_fastopen_data ? US"TFO* " : US"TFO "
5677 host_and_ident(FALSE), smtp_read_error,
5678 string_timesince(&smtp_connection_start)
5682 log_write(L_smtp_connection, LOG_MAIN, "%s %slost%s D=%s",
5683 smtp_get_connection_info(),
5684 f.tcp_in_fastopen && !f.tcp_in_fastopen_logged ? US"TFO " : US"",
5686 string_timesince(&smtp_connection_start)
5697 done = synprot_error(L_smtp_protocol_error, 503, NULL,
5698 US"ETRN is not permitted inside a transaction");
5702 log_write(L_etrn, LOG_MAIN, "ETRN %s received from %s", smtp_cmd_argument,
5703 host_and_ident(FALSE));
5705 if ((rc = acl_check(ACL_WHERE_ETRN, NULL, acl_smtp_etrn,
5706 &user_msg, &log_msg)) != OK)
5708 done = smtp_handle_acl_fail(ACL_WHERE_ETRN, rc, user_msg, log_msg);
5712 /* Compute the serialization key for this command. */
5714 etrn_serialize_key = string_sprintf("etrn-%s\n", smtp_cmd_data);
5716 /* If a command has been specified for running as a result of ETRN, we
5717 permit any argument to ETRN. If not, only the # standard form is permitted,
5718 since that is strictly the only kind of ETRN that can be implemented
5719 according to the RFC. */
5721 if (smtp_etrn_command)
5725 etrn_command = smtp_etrn_command;
5726 deliver_domain = smtp_cmd_data;
5727 rc = transport_set_up_command(&argv, smtp_etrn_command, TRUE, 0, NULL,
5728 US"ETRN processing", &error);
5729 deliver_domain = NULL;
5732 log_write(0, LOG_MAIN|LOG_PANIC, "failed to set up ETRN command: %s",
5734 smtp_printf("458 Internal failure\r\n", FALSE);
5739 /* Else set up to call Exim with the -R option. */
5743 if (*smtp_cmd_data++ != '#')
5745 done = synprot_error(L_smtp_syntax_error, 501, NULL,
5746 US"argument must begin with #");
5749 etrn_command = US"exim -R";
5750 argv = CUSS child_exec_exim(CEE_RETURN_ARGV, TRUE, NULL, TRUE,
5751 *queue_name ? 4 : 2,
5752 US"-R", smtp_cmd_data,
5753 US"-MCG", queue_name);
5756 /* If we are host-testing, don't actually do anything. */
5762 debug_printf("ETRN command is: %s\n", etrn_command);
5763 debug_printf("ETRN command execution skipped\n");
5765 if (user_msg == NULL) smtp_printf("250 OK\r\n", FALSE);
5766 else smtp_user_msg(US"250", user_msg);
5771 /* If ETRN queue runs are to be serialized, check the database to
5772 ensure one isn't already running. */
5774 if (smtp_etrn_serialize && !enq_start(etrn_serialize_key, 1))
5776 smtp_printf("458 Already processing %s\r\n", FALSE, smtp_cmd_data);
5780 /* Fork a child process and run the command. We don't want to have to
5781 wait for the process at any point, so set SIGCHLD to SIG_IGN before
5782 forking. It should be set that way anyway for external incoming SMTP,
5783 but we save and restore to be tidy. If serialization is required, we
5784 actually run the command in yet another process, so we can wait for it
5785 to complete and then remove the serialization lock. */
5787 oldsignal = signal(SIGCHLD, SIG_IGN);
5789 if ((pid = fork()) == 0)
5791 smtp_input = FALSE; /* This process is not associated with the */
5792 (void)fclose(smtp_in); /* SMTP call any more. */
5793 (void)fclose(smtp_out);
5795 signal(SIGCHLD, SIG_DFL); /* Want to catch child */
5797 /* If not serializing, do the exec right away. Otherwise, fork down
5798 into another process. */
5800 if (!smtp_etrn_serialize || (pid = fork()) == 0)
5802 DEBUG(D_exec) debug_print_argv(argv);
5803 exim_nullstd(); /* Ensure std{in,out,err} exist */
5804 execv(CS argv[0], (char *const *)argv);
5805 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "exec of \"%s\" (ETRN) failed: %s",
5806 etrn_command, strerror(errno));
5807 _exit(EXIT_FAILURE); /* paranoia */
5810 /* Obey this if smtp_serialize and the 2nd fork yielded non-zero. That
5811 is, we are in the first subprocess, after forking again. All we can do
5812 for a failing fork is to log it. Otherwise, wait for the 2nd process to
5813 complete, before removing the serialization. */
5816 log_write(0, LOG_MAIN|LOG_PANIC, "2nd fork for serialized ETRN "
5817 "failed: %s", strerror(errno));
5821 DEBUG(D_any) debug_printf("waiting for serialized ETRN process %d\n",
5823 (void)wait(&status);
5824 DEBUG(D_any) debug_printf("serialized ETRN process %d ended\n",
5828 enq_end(etrn_serialize_key);
5829 _exit(EXIT_SUCCESS);
5832 /* Back in the top level SMTP process. Check that we started a subprocess
5833 and restore the signal state. */
5837 log_write(0, LOG_MAIN|LOG_PANIC, "fork of process for ETRN failed: %s",
5839 smtp_printf("458 Unable to fork process\r\n", FALSE);
5840 if (smtp_etrn_serialize) enq_end(etrn_serialize_key);
5844 if (user_msg == NULL) smtp_printf("250 OK\r\n", FALSE);
5845 else smtp_user_msg(US"250", user_msg);
5848 signal(SIGCHLD, oldsignal);
5853 done = synprot_error(L_smtp_syntax_error, 501, NULL,
5854 US"unexpected argument data");
5858 /* This currently happens only for NULLs, but could be extended. */
5861 done = synprot_error(L_smtp_syntax_error, 0, NULL, /* Just logs */
5862 US"NUL character(s) present (shown as '?')");
5863 smtp_printf("501 NUL characters are not allowed in SMTP commands\r\n",
5870 if (smtp_inend >= smtp_inbuffer + IN_BUFFER_SIZE)
5871 smtp_inend = smtp_inbuffer + IN_BUFFER_SIZE - 1;
5872 c = smtp_inend - smtp_inptr;
5873 if (c > 150) c = 150; /* limit logged amount */
5875 incomplete_transaction_log(US"sync failure");
5876 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP protocol synchronization error "
5877 "(next input sent too soon: pipelining was%s advertised): "
5878 "rejected \"%s\" %s next input=\"%s\"",
5879 f.smtp_in_pipelining_advertised ? "" : " not",
5880 smtp_cmd_buffer, host_and_ident(TRUE),
5881 string_printing(smtp_inptr));
5882 smtp_notquit_exit(US"synchronization-error", US"554",
5883 US"SMTP synchronization error");
5884 done = 1; /* Pretend eof - drops connection */
5888 case TOO_MANY_NONMAIL_CMD:
5889 s = smtp_cmd_buffer;
5890 while (*s != 0 && !isspace(*s)) s++;
5891 incomplete_transaction_log(US"too many non-mail commands");
5892 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
5893 "nonmail commands (last was \"%.*s\")", host_and_ident(FALSE),
5894 (int)(s - smtp_cmd_buffer), smtp_cmd_buffer);
5895 smtp_notquit_exit(US"bad-commands", US"554", US"Too many nonmail commands");
5896 done = 1; /* Pretend eof - drops connection */
5899 #ifdef SUPPORT_PROXY
5900 case PROXY_FAIL_IGNORE_CMD:
5901 smtp_printf("503 Command refused, required Proxy negotiation failed\r\n", FALSE);
5906 if (unknown_command_count++ >= smtp_max_unknown_commands)
5908 log_write(L_smtp_syntax_error, LOG_MAIN,
5909 "SMTP syntax error in \"%s\" %s %s",
5910 string_printing(smtp_cmd_buffer), host_and_ident(TRUE),
5911 US"unrecognized command");
5912 incomplete_transaction_log(US"unrecognized command");
5913 smtp_notquit_exit(US"bad-commands", US"500",
5914 US"Too many unrecognized commands");
5916 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
5917 "unrecognized commands (last was \"%s\")", host_and_ident(FALSE),
5918 string_printing(smtp_cmd_buffer));
5921 done = synprot_error(L_smtp_syntax_error, 500, NULL,
5922 US"unrecognized command");
5926 /* This label is used by goto's inside loops that want to break out to
5927 the end of the command-processing loop. */
5930 last_was_rej_mail = was_rej_mail; /* Remember some last commands for */
5931 last_was_rcpt = was_rcpt; /* protocol error handling */
5935 return done - 2; /* Convert yield values */
5941 authres_smtpauth(gstring * g)
5943 if (!sender_host_authenticated)
5946 g = string_append(g, 2, US";\n\tauth=pass (", sender_host_auth_pubname);
5948 if (Ustrcmp(sender_host_auth_pubname, "tls") != 0)
5949 g = string_append(g, 2, US") smtp.auth=", authenticated_id);
5950 else if (authenticated_id)
5951 g = string_append(g, 2, US") x509.auth=", authenticated_id);
5953 g = string_catn(g, US") reason=x509.auth", 17);
5955 if (authenticated_sender)
5956 g = string_append(g, 2, US" smtp.mailfrom=", authenticated_sender);
5964 /* End of smtp_in.c */