1 /*************************************************
2 * Exim - an Internet mail transport agent *
3 *************************************************/
5 /* Copyright (c) University of Cambridge 1995 - 2017 */
6 /* See the file NOTICE for conditions of use and distribution. */
8 /* Functions for handling an incoming SMTP call. */
15 /* Initialize for TCP wrappers if so configured. It appears that the macro
16 HAVE_IPV6 is used in some versions of the tcpd.h header, so we unset it before
17 including that header, and restore its value afterwards. */
19 #ifdef USE_TCP_WRAPPERS
22 #define EXIM_HAVE_IPV6
28 #define HAVE_IPV6 TRUE
31 int allow_severity = LOG_INFO;
32 int deny_severity = LOG_NOTICE;
33 uschar *tcp_wrappers_name;
37 /* Size of buffer for reading SMTP commands. We used to use 512, as defined
38 by RFC 821. However, RFC 1869 specifies that this must be increased for SMTP
39 commands that accept arguments, and this in particular applies to AUTH, where
40 the data can be quite long. More recently this value was 2048 in Exim;
41 however, RFC 4954 (circa 2007) recommends 12288 bytes to handle AUTH. Clients
42 such as Thunderbird will send an AUTH with an initial-response for GSSAPI.
43 The maximum size of a Kerberos ticket under Windows 2003 is 12000 bytes, and
44 we need room to handle large base64-encoded AUTHs for GSSAPI.
47 #define SMTP_CMD_BUFFER_SIZE 16384
49 /* Size of buffer for reading SMTP incoming packets */
51 #define IN_BUFFER_SIZE 8192
53 /* Structure for SMTP command list */
60 short int is_mail_cmd;
63 /* Codes for identifying commands. We order them so that those that come first
64 are those for which synchronization is always required. Checking this can help
68 /* These commands are required to be synchronized, i.e. to be the last in a
69 block of commands when pipelining. */
71 HELO_CMD, EHLO_CMD, DATA_CMD, /* These are listed in the pipelining */
72 VRFY_CMD, EXPN_CMD, NOOP_CMD, /* RFC as requiring synchronization */
73 ETRN_CMD, /* This by analogy with TURN from the RFC */
74 STARTTLS_CMD, /* Required by the STARTTLS RFC */
75 TLS_AUTH_CMD, /* auto-command at start of SSL */
77 /* This is a dummy to identify the non-sync commands when pipelining */
79 NON_SYNC_CMD_PIPELINING,
81 /* These commands need not be synchronized when pipelining */
83 MAIL_CMD, RCPT_CMD, RSET_CMD,
85 /* This is a dummy to identify the non-sync commands when not pipelining */
87 NON_SYNC_CMD_NON_PIPELINING,
89 /* RFC3030 section 2: "After all MAIL and RCPT responses are collected and
90 processed the message is sent using a series of BDAT commands"
91 implies that BDAT should be synchronized. However, we see Google, at least,
92 sending MAIL,RCPT,BDAT-LAST in a single packet, clearly not waiting for
93 processing of the RCPT response(s). We shall do the same, and not require
94 synch for BDAT. Worse, as the chunk may (very likely will) follow the
95 command-header in the same packet we cannot do the usual "is there any
96 follow-on data after the command line" even for non-pipeline mode.
97 So we'll need an explicit check after reading the expected chunk amount
98 when non-pipe, before sending the ACK. */
102 /* I have been unable to find a statement about the use of pipelining
103 with AUTH, so to be on the safe side it is here, though I kind of feel
104 it should be up there with the synchronized commands. */
108 /* I'm not sure about these, but I don't think they matter. */
113 PROXY_FAIL_IGNORE_CMD,
116 /* These are specials that don't correspond to actual commands */
118 EOF_CMD, OTHER_CMD, BADARG_CMD, BADCHAR_CMD, BADSYN_CMD,
119 TOO_MANY_NONMAIL_CMD };
122 /* This is a convenience macro for adding the identity of an SMTP command
123 to the circular buffer that holds a list of the last n received. */
126 smtp_connection_had[smtp_ch_index++] = n; \
127 if (smtp_ch_index >= SMTP_HBUFF_SIZE) smtp_ch_index = 0
130 /*************************************************
131 * Local static variables *
132 *************************************************/
134 static auth_instance *authenticated_by;
135 static BOOL auth_advertised;
137 static BOOL tls_advertised;
139 static BOOL dsn_advertised;
141 static BOOL helo_required = FALSE;
142 static BOOL helo_verify = FALSE;
143 static BOOL helo_seen;
144 static BOOL helo_accept_junk;
145 static BOOL count_nonmail;
146 static BOOL pipelining_advertised;
147 static BOOL rcpt_smtp_response_same;
148 static BOOL rcpt_in_progress;
149 static int nonmail_command_count;
150 static BOOL smtp_exit_function_called = 0;
152 static BOOL smtputf8_advertised;
154 static int synprot_error_count;
155 static int unknown_command_count;
156 static int sync_cmd_limit;
157 static int smtp_write_error = 0;
159 static uschar *rcpt_smtp_response;
160 static uschar *smtp_data_buffer;
161 static uschar *smtp_cmd_data;
163 /* We need to know the position of RSET, HELO, EHLO, AUTH, and STARTTLS. Their
164 final fields of all except AUTH are forced TRUE at the start of a new message
165 setup, to allow one of each between messages that is not counted as a nonmail
166 command. (In fact, only one of HELO/EHLO is not counted.) Also, we have to
167 allow a new EHLO after starting up TLS.
169 AUTH is "falsely" labelled as a mail command initially, so that it doesn't get
170 counted. However, the flag is changed when AUTH is received, so that multiple
171 failing AUTHs will eventually hit the limit. After a successful AUTH, another
172 AUTH is already forbidden. After a TLS session is started, AUTH's flag is again
173 forced TRUE, to allow for the re-authentication that can happen at that point.
175 QUIT is also "falsely" labelled as a mail command so that it doesn't up the
176 count of non-mail commands and possibly provoke an error.
178 tls_auth is a pseudo-command, never expected in input. It is activated
179 on TLS startup and looks for a tls authenticator. */
181 static smtp_cmd_list cmd_list[] = {
182 /* name len cmd has_arg is_mail_cmd */
184 { "rset", sizeof("rset")-1, RSET_CMD, FALSE, FALSE }, /* First */
185 { "helo", sizeof("helo")-1, HELO_CMD, TRUE, FALSE },
186 { "ehlo", sizeof("ehlo")-1, EHLO_CMD, TRUE, FALSE },
187 { "auth", sizeof("auth")-1, AUTH_CMD, TRUE, TRUE },
189 { "starttls", sizeof("starttls")-1, STARTTLS_CMD, FALSE, FALSE },
190 { "tls_auth", 0, TLS_AUTH_CMD, FALSE, TRUE },
193 /* If you change anything above here, also fix the definitions below. */
195 { "mail from:", sizeof("mail from:")-1, MAIL_CMD, TRUE, TRUE },
196 { "rcpt to:", sizeof("rcpt to:")-1, RCPT_CMD, TRUE, TRUE },
197 { "data", sizeof("data")-1, DATA_CMD, FALSE, TRUE },
198 { "bdat", sizeof("bdat")-1, BDAT_CMD, TRUE, TRUE },
199 { "quit", sizeof("quit")-1, QUIT_CMD, FALSE, TRUE },
200 { "noop", sizeof("noop")-1, NOOP_CMD, TRUE, FALSE },
201 { "etrn", sizeof("etrn")-1, ETRN_CMD, TRUE, FALSE },
202 { "vrfy", sizeof("vrfy")-1, VRFY_CMD, TRUE, FALSE },
203 { "expn", sizeof("expn")-1, EXPN_CMD, TRUE, FALSE },
204 { "help", sizeof("help")-1, HELP_CMD, TRUE, FALSE }
207 static smtp_cmd_list *cmd_list_end =
208 cmd_list + sizeof(cmd_list)/sizeof(smtp_cmd_list);
210 #define CMD_LIST_RSET 0
211 #define CMD_LIST_HELO 1
212 #define CMD_LIST_EHLO 2
213 #define CMD_LIST_AUTH 3
214 #define CMD_LIST_STARTTLS 4
215 #define CMD_LIST_TLS_AUTH 5
217 /* This list of names is used for performing the smtp_no_mail logging action.
218 It must be kept in step with the SCH_xxx enumerations. */
220 static uschar *smtp_names[] =
222 US"NONE", US"AUTH", US"DATA", US"BDAT", US"EHLO", US"ETRN", US"EXPN",
223 US"HELO", US"HELP", US"MAIL", US"NOOP", US"QUIT", US"RCPT", US"RSET",
224 US"STARTTLS", US"VRFY" };
226 static uschar *protocols_local[] = {
227 US"local-smtp", /* HELO */
228 US"local-smtps", /* The rare case EHLO->STARTTLS->HELO */
229 US"local-esmtp", /* EHLO */
230 US"local-esmtps", /* EHLO->STARTTLS->EHLO */
231 US"local-esmtpa", /* EHLO->AUTH */
232 US"local-esmtpsa" /* EHLO->STARTTLS->EHLO->AUTH */
234 static uschar *protocols[] = {
236 US"smtps", /* The rare case EHLO->STARTTLS->HELO */
237 US"esmtp", /* EHLO */
238 US"esmtps", /* EHLO->STARTTLS->EHLO */
239 US"esmtpa", /* EHLO->AUTH */
240 US"esmtpsa" /* EHLO->STARTTLS->EHLO->AUTH */
245 #define pcrpted 1 /* added to pextend or pnormal */
246 #define pauthed 2 /* added to pextend */
248 /* Sanity check and validate optional args to MAIL FROM: envelope */
251 ENV_MAIL_OPT_SIZE, ENV_MAIL_OPT_BODY, ENV_MAIL_OPT_AUTH,
255 ENV_MAIL_OPT_RET, ENV_MAIL_OPT_ENVID,
261 uschar * name; /* option requested during MAIL cmd */
262 int value; /* enum type */
263 BOOL need_value; /* TRUE requires value (name=value pair format)
264 FALSE is a singleton */
266 static env_mail_type_t env_mail_type_list[] = {
267 { US"SIZE", ENV_MAIL_OPT_SIZE, TRUE },
268 { US"BODY", ENV_MAIL_OPT_BODY, TRUE },
269 { US"AUTH", ENV_MAIL_OPT_AUTH, TRUE },
271 { US"PRDR", ENV_MAIL_OPT_PRDR, FALSE },
273 { US"RET", ENV_MAIL_OPT_RET, TRUE },
274 { US"ENVID", ENV_MAIL_OPT_ENVID, TRUE },
276 { US"SMTPUTF8",ENV_MAIL_OPT_UTF8, FALSE }, /* rfc6531 */
278 /* keep this the last entry */
279 { US"NULL", ENV_MAIL_OPT_NULL, FALSE },
282 /* When reading SMTP from a remote host, we have to use our own versions of the
283 C input-reading functions, in order to be able to flush the SMTP output only
284 when about to read more data from the socket. This is the only way to get
285 optimal performance when the client is using pipelining. Flushing for every
286 command causes a separate packet and reply packet each time; saving all the
287 responses up (when pipelining) combines them into one packet and one response.
289 For simplicity, these functions are used for *all* SMTP input, not only when
290 receiving over a socket. However, after setting up a secure socket (SSL), input
291 is read via the OpenSSL library, and another set of functions is used instead
294 These functions are set in the receive_getc etc. variables and called with the
295 same interface as the C functions. However, since there can only ever be
296 one incoming SMTP call, we just use a single buffer and flags. There is no need
297 to implement a complicated private FILE-like structure.*/
299 static uschar *smtp_inbuffer;
300 static uschar *smtp_inptr;
301 static uschar *smtp_inend;
302 static int smtp_had_eof;
303 static int smtp_had_error;
306 /* forward declarations */
307 static int smtp_read_command(BOOL check_sync, unsigned buffer_lim);
308 static int synprot_error(int type, int code, uschar *data, uschar *errmess);
309 static void smtp_quit_handler(uschar **, uschar **);
310 static void smtp_rset_handler(void);
312 /*************************************************
313 * Recheck synchronization *
314 *************************************************/
316 /* Synchronization checks can never be perfect because a packet may be on its
317 way but not arrived when the check is done. Such checks can in any case only be
318 done when TLS is not in use. Normally, the checks happen when commands are
319 read: Exim ensures that there is no more input in the input buffer. In normal
320 cases, the response to the command will be fast, and there is no further check.
322 However, for some commands an ACL is run, and that can include delays. In those
323 cases, it is useful to do another check on the input just before sending the
324 response. This also applies at the start of a connection. This function does
325 that check by means of the select() function, as long as the facility is not
326 disabled or inappropriate. A failure of select() is ignored.
328 When there is unwanted input, we read it so that it appears in the log of the
332 Returns: TRUE if all is well; FALSE if there is input pending
340 struct timeval tzero;
342 if (!smtp_enforce_sync || sender_host_address == NULL ||
343 sender_host_notsocket || tls_in.active >= 0)
346 fd = fileno(smtp_in);
351 rc = select(fd + 1, (SELECT_ARG2_TYPE *)&fds, NULL, NULL, &tzero);
353 if (rc <= 0) return TRUE; /* Not ready to read */
354 rc = smtp_getc(GETC_BUFFER_UNLIMITED);
355 if (rc < 0) return TRUE; /* End of file or error */
358 rc = smtp_inend - smtp_inptr;
359 if (rc > 150) rc = 150;
366 /*************************************************
367 * Log incomplete transactions *
368 *************************************************/
370 /* This function is called after a transaction has been aborted by RSET, QUIT,
371 connection drops or other errors. It logs the envelope information received
372 so far in order to preserve address verification attempts.
374 Argument: string to indicate what aborted the transaction
379 incomplete_transaction_log(uschar *what)
381 if (sender_address == NULL || /* No transaction in progress */
382 !LOGGING(smtp_incomplete_transaction))
385 /* Build list of recipients for logging */
387 if (recipients_count > 0)
390 raw_recipients = store_get(recipients_count * sizeof(uschar *));
391 for (i = 0; i < recipients_count; i++)
392 raw_recipients[i] = recipients_list[i].address;
393 raw_recipients_count = recipients_count;
396 log_write(L_smtp_incomplete_transaction, LOG_MAIN|LOG_SENDER|LOG_RECIPIENTS,
397 "%s incomplete transaction (%s)", host_and_ident(TRUE), what);
403 /* Refill the buffer, and notify DKIM verification code.
404 Return false for error or EOF.
408 smtp_refill(unsigned lim)
411 if (!smtp_out) return FALSE;
413 if (smtp_receive_timeout > 0) alarm(smtp_receive_timeout);
415 /* Limit amount read, so non-message data is not fed to DKIM */
417 rc = read(fileno(smtp_in), smtp_inbuffer, MIN(IN_BUFFER_SIZE, lim));
422 /* Must put the error text in fixed store, because this might be during
423 header reading, where it releases unused store above the header. */
426 smtp_had_error = save_errno;
427 smtp_read_error = string_copy_malloc(
428 string_sprintf(" (error: %s)", strerror(save_errno)));
430 else smtp_had_eof = 1;
434 dkim_exim_verify_feed(smtp_inbuffer, rc);
436 smtp_inend = smtp_inbuffer + rc;
437 smtp_inptr = smtp_inbuffer;
441 /*************************************************
442 * SMTP version of getc() *
443 *************************************************/
445 /* This gets the next byte from the SMTP input buffer. If the buffer is empty,
446 it flushes the output, and refills the buffer, with a timeout. The signal
447 handler is set appropriately by the calling function. This function is not used
448 after a connection has negotiated itself into an TLS/SSL state.
450 Arguments: lim Maximum amount to read/buffer
451 Returns: the next character or EOF
455 smtp_getc(unsigned lim)
457 if (smtp_inptr >= smtp_inend)
458 if (!smtp_refill(lim))
460 return *smtp_inptr++;
464 smtp_getbuf(unsigned * len)
469 if (smtp_inptr >= smtp_inend)
470 if (!smtp_refill(*len))
471 { *len = 0; return NULL; }
473 if ((size = smtp_inend - smtp_inptr) > *len) size = *len;
484 int n = smtp_inend - smtp_inptr;
486 dkim_exim_verify_feed(smtp_inptr, n);
491 /* Get a byte from the smtp input, in CHUNKING mode. Handle ack of the
492 previous BDAT chunk and getting new ones when we run out. Uses the
493 underlying smtp_getc or tls_getc both for that and for getting the
494 (buffered) data byte. EOD signals (an expected) no further data.
495 ERR signals a protocol error, and EOF a closed input stream.
497 Called from read_bdat_smtp() in receive.c for the message body, but also
498 by the headers read loop in receive_msg(); manipulates chunking_state
499 to handle the BDAT command/response.
500 Placed here due to the correlation with the above smtp_getc(), which it wraps,
501 and also by the need to do smtp command/response handling.
503 Arguments: lim (ignored)
504 Returns: the next character or ERR, EOD or EOF
508 bdat_getc(unsigned lim)
510 uschar * user_msg = NULL;
519 if (chunking_data_left > 0)
520 return lwr_receive_getc(chunking_data_left--);
522 receive_getc = lwr_receive_getc;
523 receive_getbuf = lwr_receive_getbuf;
524 receive_ungetc = lwr_receive_ungetc;
526 dkim_save = dkim_collect_input;
527 dkim_collect_input = FALSE;
530 /* Unless PIPELINING was offered, there should be no next command
531 until after we ack that chunk */
533 if (!pipelining_advertised && !check_sync())
535 incomplete_transaction_log(US"sync failure");
536 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP protocol synchronization error "
537 "(next input sent too soon: pipelining was not advertised): "
538 "rejected \"%s\" %s next input=\"%s\"",
539 smtp_cmd_buffer, host_and_ident(TRUE),
540 string_printing(smtp_inptr));
541 (void) synprot_error(L_smtp_protocol_error, 554, NULL,
542 US"SMTP synchronization error");
543 goto repeat_until_rset;
546 /* If not the last, ack the received chunk. The last response is delayed
547 until after the data ACL decides on it */
549 if (chunking_state == CHUNKING_LAST)
552 dkim_exim_verify_feed(NULL, 0); /* notify EOD */
557 smtp_printf("250 %u byte chunk received\r\n", chunking_datasize);
558 chunking_state = CHUNKING_OFFERED;
559 DEBUG(D_receive) debug_printf("chunking state %d\n", (int)chunking_state);
561 /* Expect another BDAT cmd from input. RFC 3030 says nothing about
562 QUIT, RSET or NOOP but handling them seems obvious */
565 switch(smtp_read_command(TRUE, 1))
568 (void) synprot_error(L_smtp_protocol_error, 503, NULL,
569 US"only BDAT permissible after non-LAST BDAT");
572 switch(smtp_read_command(TRUE, 1))
574 case QUIT_CMD: smtp_quit_handler(&user_msg, &log_msg); /*FALLTHROUGH */
575 case EOF_CMD: return EOF;
576 case RSET_CMD: smtp_rset_handler(); return ERR;
577 default: if (synprot_error(L_smtp_protocol_error, 503, NULL,
578 US"only RSET accepted now") > 0)
580 goto repeat_until_rset;
584 smtp_quit_handler(&user_msg, &log_msg);
595 smtp_printf("250 OK\r\n");
602 if (sscanf(CS smtp_cmd_data, "%u %n", &chunking_datasize, &n) < 1)
604 (void) synprot_error(L_smtp_protocol_error, 501, NULL,
605 US"missing size for BDAT command");
608 chunking_state = strcmpic(smtp_cmd_data+n, US"LAST") == 0
609 ? CHUNKING_LAST : CHUNKING_ACTIVE;
610 chunking_data_left = chunking_datasize;
611 DEBUG(D_receive) debug_printf("chunking state %d, %d bytes\n",
612 (int)chunking_state, chunking_data_left);
614 if (chunking_datasize == 0)
615 if (chunking_state == CHUNKING_LAST)
619 (void) synprot_error(L_smtp_protocol_error, 504, NULL,
620 US"zero size for BDAT command");
621 goto repeat_until_rset;
624 receive_getc = bdat_getc;
625 receive_getbuf = bdat_getbuf;
626 receive_ungetc = bdat_ungetc;
628 dkim_collect_input = dkim_save;
630 break; /* to top of main loop */
637 bdat_getbuf(unsigned * len)
641 if (chunking_data_left <= 0)
642 { *len = 0; return NULL; }
644 if (*len > chunking_data_left) *len = chunking_data_left;
645 buf = lwr_receive_getbuf(len); /* Either smtp_getbuf or tls_getbuf */
646 chunking_data_left -= *len;
651 bdat_flush_data(void)
653 unsigned n = chunking_data_left;
654 (void) bdat_getbuf(&n);
656 receive_getc = lwr_receive_getc;
657 receive_getbuf = lwr_receive_getbuf;
658 receive_ungetc = lwr_receive_ungetc;
660 if (chunking_state != CHUNKING_LAST)
662 chunking_state = CHUNKING_OFFERED;
663 DEBUG(D_receive) debug_printf("chunking state %d\n", (int)chunking_state);
670 /*************************************************
671 * SMTP version of ungetc() *
672 *************************************************/
674 /* Puts a character back in the input buffer. Only ever
680 Returns: the character
694 chunking_data_left++;
695 return lwr_receive_ungetc(ch);
700 /*************************************************
701 * SMTP version of feof() *
702 *************************************************/
704 /* Tests for a previous EOF
707 Returns: non-zero if the eof flag is set
719 /*************************************************
720 * SMTP version of ferror() *
721 *************************************************/
723 /* Tests for a previous read error, and returns with errno
724 restored to what it was when the error was detected.
727 Returns: non-zero if the error flag is set
733 errno = smtp_had_error;
734 return smtp_had_error;
739 /*************************************************
740 * Test for characters in the SMTP buffer *
741 *************************************************/
743 /* Used at the end of a message
752 return smtp_inptr < smtp_inend;
757 /*************************************************
758 * Write formatted string to SMTP channel *
759 *************************************************/
761 /* This is a separate function so that we don't have to repeat everything for
762 TLS support or debugging. It is global so that the daemon and the
763 authentication functions can use it. It does not return any error indication,
764 because major problems such as dropped connections won't show up till an output
765 flush for non-TLS connections. The smtp_fflush() function is available for
766 checking that: for convenience, TLS output errors are remembered here so that
767 they are also picked up later by smtp_fflush().
771 ... optional arguments
777 smtp_printf(const char *format, ...)
781 va_start(ap, format);
782 smtp_vprintf(format, ap);
786 /* This is split off so that verify.c:respond_printf() can, in effect, call
787 smtp_printf(), bearing in mind that in C a vararg function can't directly
788 call another vararg function, only a function which accepts a va_list. */
791 smtp_vprintf(const char *format, va_list ap)
795 yield = string_vformat(big_buffer, big_buffer_size, format, ap);
799 void *reset_point = store_get(0);
800 uschar *msg_copy, *cr, *end;
801 msg_copy = string_copy(big_buffer);
802 end = msg_copy + Ustrlen(msg_copy);
803 while ((cr = Ustrchr(msg_copy, '\r')) != NULL) /* lose CRs */
804 memmove(cr, cr + 1, (end--) - cr);
805 debug_printf("SMTP>> %s", msg_copy);
806 store_reset(reset_point);
811 log_write(0, LOG_MAIN|LOG_PANIC, "string too large in smtp_printf()");
812 smtp_closedown(US"Unexpected error");
813 exim_exit(EXIT_FAILURE);
816 /* If this is the first output for a (non-batch) RCPT command, see if all RCPTs
817 have had the same. Note: this code is also present in smtp_respond(). It would
818 be tidier to have it only in one place, but when it was added, it was easier to
819 do it that way, so as not to have to mess with the code for the RCPT command,
820 which sometimes uses smtp_printf() and sometimes smtp_respond(). */
822 if (rcpt_in_progress)
824 if (rcpt_smtp_response == NULL)
825 rcpt_smtp_response = string_copy(big_buffer);
826 else if (rcpt_smtp_response_same &&
827 Ustrcmp(rcpt_smtp_response, big_buffer) != 0)
828 rcpt_smtp_response_same = FALSE;
829 rcpt_in_progress = FALSE;
832 /* Now write the string */
835 if (tls_in.active >= 0)
837 if (tls_write(TRUE, big_buffer, Ustrlen(big_buffer)) < 0)
838 smtp_write_error = -1;
843 if (fprintf(smtp_out, "%s", big_buffer) < 0) smtp_write_error = -1;
848 /*************************************************
849 * Flush SMTP out and check for error *
850 *************************************************/
852 /* This function isn't currently used within Exim (it detects errors when it
853 tries to read the next SMTP input), but is available for use in local_scan().
854 For non-TLS connections, it flushes the output and checks for errors. For
855 TLS-connections, it checks for a previously-detected TLS write error.
858 Returns: 0 for no error; -1 after an error
864 if (tls_in.active < 0 && fflush(smtp_out) != 0) smtp_write_error = -1;
865 return smtp_write_error;
870 /*************************************************
871 * SMTP command read timeout *
872 *************************************************/
874 /* Signal handler for timing out incoming SMTP commands. This attempts to
877 Argument: signal number (SIGALRM)
882 command_timeout_handler(int sig)
884 sig = sig; /* Keep picky compilers happy */
885 log_write(L_lost_incoming_connection,
886 LOG_MAIN, "SMTP command timeout on%s connection from %s",
887 (tls_in.active >= 0)? " TLS" : "",
888 host_and_ident(FALSE));
889 if (smtp_batched_input)
890 moan_smtp_batch(NULL, "421 SMTP command timeout"); /* Does not return */
891 smtp_notquit_exit(US"command-timeout", US"421",
892 US"%s: SMTP command timeout - closing connection", smtp_active_hostname);
893 exim_exit(EXIT_FAILURE);
898 /*************************************************
900 *************************************************/
902 /* Signal handler for handling SIGTERM. Again, try to finish tidily.
904 Argument: signal number (SIGTERM)
909 command_sigterm_handler(int sig)
911 sig = sig; /* Keep picky compilers happy */
912 log_write(0, LOG_MAIN, "%s closed after SIGTERM", smtp_get_connection_info());
913 if (smtp_batched_input)
914 moan_smtp_batch(NULL, "421 SIGTERM received"); /* Does not return */
915 smtp_notquit_exit(US"signal-exit", US"421",
916 US"%s: Service not available - closing connection", smtp_active_hostname);
917 exim_exit(EXIT_FAILURE);
924 /*************************************************
925 * Restore socket timeout to previous value *
926 *************************************************/
927 /* If the previous value was successfully retrieved, restore
928 it before returning control to the non-proxy routines
930 Arguments: fd - File descriptor for input
931 get_ok - Successfully retrieved previous values
932 tvtmp - Time struct with previous values
933 vslen - Length of time struct
937 restore_socket_timeout(int fd, int get_ok, struct timeval * tvtmp, socklen_t vslen)
940 (void) setsockopt(fd, SOL_SOCKET, SO_RCVTIMEO, CS tvtmp, vslen);
943 /*************************************************
944 * Check if host is required proxy host *
945 *************************************************/
946 /* The function determines if inbound host will be a regular smtp host
947 or if it is configured that it must use Proxy Protocol. A local
955 check_proxy_protocol_host()
959 if ( sender_host_address
960 && (rc = verify_check_this_host(CUSS &hosts_proxy, NULL, NULL,
961 sender_host_address, NULL)) == OK)
964 debug_printf("Detected proxy protocol configured host\n");
965 proxy_session = TRUE;
967 return proxy_session;
971 /*************************************************
972 * Read data until newline or end of buffer *
973 *************************************************/
974 /* While SMTP is server-speaks-first, TLS is client-speaks-first, so we can't
975 read an entire buffer and assume there will be nothing past a proxy protocol
976 header. Our approach normally is to use stdio, but again that relies upon
977 "STARTTLS\r\n" and a server response before the client starts TLS handshake, or
978 reading _nothing_ before client TLS handshake. So we don't want to use the
979 usual buffering reads which may read enough to block TLS starting.
981 So unfortunately we're down to "read one byte at a time, with a syscall each,
982 and expect a little overhead", for all proxy-opened connections which are v1,
983 just to handle the TLS-on-connect case. Since SSL functions wrap the
984 underlying fd, we can't assume that we can feed them any already-read content.
986 We need to know where to read to, the max capacity, and we'll read until we
987 get a CR and one more character. Let the caller scream if it's CR+!LF.
989 Return the amount read.
993 swallow_until_crlf(int fd, uschar *base, int already, int capacity)
995 uschar *to = base + already;
1001 /* For "PROXY UNKNOWN\r\n" we, at time of writing, expect to have read
1002 up through the \r; for the _normal_ case, we haven't yet seen the \r. */
1004 cr = memchr(base, '\r', already);
1007 if ((cr - base) < already - 1)
1009 /* \r and presumed \n already within what we have; probably not
1010 actually proxy protocol, but abort cleanly. */
1013 /* \r is last character read, just need one more. */
1017 while (capacity > 0)
1019 do { ret = recv(fd, to, 1, 0); } while (ret == -1 && errno == EINTR);
1031 /* reached end without having room for a final newline, abort */
1036 /*************************************************
1037 * Setup host for proxy protocol *
1038 *************************************************/
1039 /* The function configures the connection based on a header from the
1040 inbound host to use Proxy Protocol. The specification is very exact
1041 so exit with an error if do not find the exact required pieces. This
1042 includes an incorrect number of spaces separating args.
1045 Returns: Boolean success
1049 setup_proxy_protocol_host()
1061 struct { /* TCP/UDP over IPv4, len = 12 */
1067 struct { /* TCP/UDP over IPv6, len = 36 */
1068 uint8_t src_addr[16];
1069 uint8_t dst_addr[16];
1073 struct { /* AF_UNIX sockets, len = 216 */
1074 uschar src_addr[108];
1075 uschar dst_addr[108];
1081 /* Temp variables used in PPv2 address:port parsing */
1083 char tmpip[INET_ADDRSTRLEN];
1084 struct sockaddr_in tmpaddr;
1085 char tmpip6[INET6_ADDRSTRLEN];
1086 struct sockaddr_in6 tmpaddr6;
1088 /* We can't read "all data until end" because while SMTP is
1089 server-speaks-first, the TLS handshake is client-speaks-first, so for
1090 TLS-on-connect ports the proxy protocol header will usually be immediately
1091 followed by a TLS handshake, and with N TLS libraries, we can't reliably
1092 reinject data for reading by those. So instead we first read "enough to be
1093 safely read within the header, and figure out how much more to read".
1094 For v1 we will later read to the end-of-line, for v2 we will read based upon
1097 The v2 sig is 12 octets, and another 4 gets us the length, so we know how much
1098 data is needed total. For v1, where the line looks like:
1099 PROXY TCPn L3src L3dest SrcPort DestPort \r\n
1101 However, for v1 there's also `PROXY UNKNOWN\r\n` which is only 15 octets.
1102 We seem to support that. So, if we read 14 octets then we can tell if we're
1103 v2 or v1. If we're v1, we can continue reading as normal.
1105 If we're v2, we can't slurp up the entire header. We need the length in the
1106 15th & 16th octets, then to read everything after that.
1108 So to safely handle v1 and v2, with client-sent-first supported correctly,
1109 we have to do a minimum of 3 read calls, not 1. Eww.
1112 #define PROXY_INITIAL_READ 14
1113 #define PROXY_V2_HEADER_SIZE 16
1114 #if PROXY_INITIAL_READ > PROXY_V2_HEADER_SIZE
1115 # error Code bug in sizes of data to read for proxy usage
1120 int fd = fileno(smtp_in);
1121 const char v2sig[12] = "\x0D\x0A\x0D\x0A\x00\x0D\x0A\x51\x55\x49\x54\x0A";
1122 uschar * iptype; /* To display debug info */
1124 struct timeval tvtmp;
1125 socklen_t vslen = sizeof(struct timeval);
1128 /* Save current socket timeout values */
1129 get_ok = getsockopt(fd, SOL_SOCKET, SO_RCVTIMEO, CS &tvtmp, &vslen);
1131 /* Proxy Protocol host must send header within a short time
1132 (default 3 seconds) or it's considered invalid */
1133 tv.tv_sec = PROXY_NEGOTIATION_TIMEOUT_SEC;
1134 tv.tv_usec = PROXY_NEGOTIATION_TIMEOUT_USEC;
1135 if (setsockopt(fd, SOL_SOCKET, SO_RCVTIMEO, CS &tv, sizeof(tv)) < 0)
1140 /* The inbound host was declared to be a Proxy Protocol host, so
1141 don't do a PEEK into the data, actually slurp up enough to be
1142 "safe". Can't take it all because TLS-on-connect clients follow
1143 immediately with TLS handshake. */
1144 ret = recv(fd, &hdr, PROXY_INITIAL_READ, 0);
1146 while (ret == -1 && errno == EINTR);
1151 /* For v2, handle reading the length, and then the rest. */
1152 if ((ret == PROXY_INITIAL_READ) && (memcmp(&hdr.v2, v2sig, sizeof(v2sig)) == 0))
1157 /* First get the length fields. */
1160 retmore = recv(fd, (uschar*)&hdr + ret, PROXY_V2_HEADER_SIZE - PROXY_INITIAL_READ, 0);
1161 } while (retmore == -1 && errno == EINTR);
1166 ver = (hdr.v2.ver_cmd & 0xf0) >> 4;
1168 /* May 2014: haproxy combined the version and command into one byte to
1169 allow two full bytes for the length field in order to proxy SSL
1170 connections. SSL Proxy is not supported in this version of Exim, but
1171 must still separate values here. */
1175 DEBUG(D_receive) debug_printf("Invalid Proxy Protocol version: %d\n", ver);
1179 /* The v2 header will always be 16 bytes per the spec. */
1180 size = 16 + ntohs(hdr.v2.len);
1181 DEBUG(D_receive) debug_printf("Detected PROXYv2 header, size %d (limit %d)\n",
1182 size, (int)sizeof(hdr));
1184 /* We should now have 16 octets (PROXY_V2_HEADER_SIZE), and we know the total
1185 amount that we need. Double-check that the size is not unreasonable, then
1187 if (size > sizeof(hdr))
1189 DEBUG(D_receive) debug_printf("PROXYv2 header size unreasonably large; security attack?\n");
1197 retmore = recv(fd, (uschar*)&hdr + ret, size-ret, 0);
1198 } while (retmore == -1 && errno == EINTR);
1202 DEBUG(D_receive) debug_printf("PROXYv2: have %d/%d required octets\n", ret, size);
1203 } while (ret < size);
1205 } /* end scope for getting rest of data for v2 */
1207 /* At this point: if PROXYv2, we've read the exact size required for all data;
1208 if PROXYv1 then we've read "less than required for any valid line" and should
1211 if (ret >= 16 && memcmp(&hdr.v2, v2sig, 12) == 0)
1213 uint8_t cmd = (hdr.v2.ver_cmd & 0x0f);
1217 case 0x01: /* PROXY command */
1220 case 0x11: /* TCPv4 address type */
1222 tmpaddr.sin_addr.s_addr = hdr.v2.addr.ip4.src_addr;
1223 inet_ntop(AF_INET, &tmpaddr.sin_addr, CS &tmpip, sizeof(tmpip));
1224 if (!string_is_ip_address(US tmpip, NULL))
1226 DEBUG(D_receive) debug_printf("Invalid %s source IP\n", iptype);
1229 proxy_local_address = sender_host_address;
1230 sender_host_address = string_copy(US tmpip);
1231 tmpport = ntohs(hdr.v2.addr.ip4.src_port);
1232 proxy_local_port = sender_host_port;
1233 sender_host_port = tmpport;
1234 /* Save dest ip/port */
1235 tmpaddr.sin_addr.s_addr = hdr.v2.addr.ip4.dst_addr;
1236 inet_ntop(AF_INET, &tmpaddr.sin_addr, CS &tmpip, sizeof(tmpip));
1237 if (!string_is_ip_address(US tmpip, NULL))
1239 DEBUG(D_receive) debug_printf("Invalid %s dest port\n", iptype);
1242 proxy_external_address = string_copy(US tmpip);
1243 tmpport = ntohs(hdr.v2.addr.ip4.dst_port);
1244 proxy_external_port = tmpport;
1246 case 0x21: /* TCPv6 address type */
1248 memmove(tmpaddr6.sin6_addr.s6_addr, hdr.v2.addr.ip6.src_addr, 16);
1249 inet_ntop(AF_INET6, &tmpaddr6.sin6_addr, CS &tmpip6, sizeof(tmpip6));
1250 if (!string_is_ip_address(US tmpip6, NULL))
1252 DEBUG(D_receive) debug_printf("Invalid %s source IP\n", iptype);
1255 proxy_local_address = sender_host_address;
1256 sender_host_address = string_copy(US tmpip6);
1257 tmpport = ntohs(hdr.v2.addr.ip6.src_port);
1258 proxy_local_port = sender_host_port;
1259 sender_host_port = tmpport;
1260 /* Save dest ip/port */
1261 memmove(tmpaddr6.sin6_addr.s6_addr, hdr.v2.addr.ip6.dst_addr, 16);
1262 inet_ntop(AF_INET6, &tmpaddr6.sin6_addr, CS &tmpip6, sizeof(tmpip6));
1263 if (!string_is_ip_address(US tmpip6, NULL))
1265 DEBUG(D_receive) debug_printf("Invalid %s dest port\n", iptype);
1268 proxy_external_address = string_copy(US tmpip6);
1269 tmpport = ntohs(hdr.v2.addr.ip6.dst_port);
1270 proxy_external_port = tmpport;
1274 debug_printf("Unsupported PROXYv2 connection type: 0x%02x\n",
1278 /* Unsupported protocol, keep local connection address */
1280 case 0x00: /* LOCAL command */
1281 /* Keep local connection address for LOCAL */
1286 debug_printf("Unsupported PROXYv2 command: 0x%x\n", cmd);
1290 else if (ret >= 8 && memcmp(hdr.v1.line, "PROXY", 5) == 0)
1294 uschar *sp; /* Utility variables follow */
1299 /* get the rest of the line */
1300 r2 = swallow_until_crlf(fd, (uschar*)&hdr, ret, sizeof(hdr)-ret);
1305 p = string_copy(hdr.v1.line);
1306 end = memchr(p, '\r', ret - 1);
1308 if (!end || (end == (uschar*)&hdr + ret) || end[1] != '\n')
1310 DEBUG(D_receive) debug_printf("Partial or invalid PROXY header\n");
1313 *end = '\0'; /* Terminate the string */
1314 size = end + 2 - p; /* Skip header + CRLF */
1315 DEBUG(D_receive) debug_printf("Detected PROXYv1 header\n");
1316 DEBUG(D_receive) debug_printf("Bytes read not within PROXY header: %d\n", ret - size);
1317 /* Step through the string looking for the required fields. Ensure
1318 strict adherence to required formatting, exit for any error. */
1320 if (!isspace(*(p++)))
1322 DEBUG(D_receive) debug_printf("Missing space after PROXY command\n");
1325 if (!Ustrncmp(p, CCS"TCP4", 4))
1327 else if (!Ustrncmp(p,CCS"TCP6", 4))
1329 else if (!Ustrncmp(p,CCS"UNKNOWN", 7))
1331 iptype = US"Unknown";
1336 DEBUG(D_receive) debug_printf("Invalid TCP type\n");
1340 p += Ustrlen(iptype);
1341 if (!isspace(*(p++)))
1343 DEBUG(D_receive) debug_printf("Missing space after TCP4/6 command\n");
1346 /* Find the end of the arg */
1347 if ((sp = Ustrchr(p, ' ')) == NULL)
1350 debug_printf("Did not find proxied src %s\n", iptype);
1354 if(!string_is_ip_address(p, NULL))
1357 debug_printf("Proxied src arg is not an %s address\n", iptype);
1360 proxy_local_address = sender_host_address;
1361 sender_host_address = p;
1363 if ((sp = Ustrchr(p, ' ')) == NULL)
1366 debug_printf("Did not find proxy dest %s\n", iptype);
1370 if(!string_is_ip_address(p, NULL))
1373 debug_printf("Proxy dest arg is not an %s address\n", iptype);
1376 proxy_external_address = p;
1378 if ((sp = Ustrchr(p, ' ')) == NULL)
1380 DEBUG(D_receive) debug_printf("Did not find proxied src port\n");
1384 tmp_port = strtol(CCS p, &endc, 10);
1385 if (*endc || tmp_port == 0)
1388 debug_printf("Proxied src port '%s' not an integer\n", p);
1391 proxy_local_port = sender_host_port;
1392 sender_host_port = tmp_port;
1394 if ((sp = Ustrchr(p, '\0')) == NULL)
1396 DEBUG(D_receive) debug_printf("Did not find proxy dest port\n");
1399 tmp_port = strtol(CCS p, &endc, 10);
1400 if (*endc || tmp_port == 0)
1403 debug_printf("Proxy dest port '%s' not an integer\n", p);
1406 proxy_external_port = tmp_port;
1407 /* Already checked for /r /n above. Good V1 header received. */
1411 /* Wrong protocol */
1412 DEBUG(D_receive) debug_printf("Invalid proxy protocol version negotiation\n");
1413 (void) swallow_until_crlf(fd, (uschar*)&hdr, ret, sizeof(hdr)-ret);
1419 debug_printf("Valid %s sender from Proxy Protocol header\n", iptype);
1420 yield = proxy_session;
1422 /* Don't flush any potential buffer contents. Any input on proxyfail
1423 should cause a synchronization failure */
1426 restore_socket_timeout(fd, get_ok, &tvtmp, vslen);
1431 sender_host_name = NULL;
1432 (void) host_name_lookup();
1433 host_build_sender_fullhost();
1437 proxy_session_failed = TRUE;
1439 debug_printf("Failure to extract proxied host, only QUIT allowed\n");
1446 /*************************************************
1447 * Read one command line *
1448 *************************************************/
1450 /* Strictly, SMTP commands coming over the net are supposed to end with CRLF.
1451 There are sites that don't do this, and in any case internal SMTP probably
1452 should check only for LF. Consequently, we check here for LF only. The line
1453 ends up with [CR]LF removed from its end. If we get an overlong line, treat as
1454 an unknown command. The command is read into the global smtp_cmd_buffer so that
1455 it is available via $smtp_command.
1457 The character reading routine sets up a timeout for each block actually read
1458 from the input (which may contain more than one command). We set up a special
1459 signal handler that closes down the session on a timeout. Control does not
1460 return when it runs.
1463 check_sync if TRUE, check synchronization rules if global option is TRUE
1464 buffer_lim maximum to buffer in lower layer
1466 Returns: a code identifying the command (enumerated above)
1470 smtp_read_command(BOOL check_sync, unsigned buffer_lim)
1475 BOOL hadnull = FALSE;
1477 os_non_restarting_signal(SIGALRM, command_timeout_handler);
1479 while ((c = (receive_getc)(buffer_lim)) != '\n' && c != EOF)
1481 if (ptr >= SMTP_CMD_BUFFER_SIZE)
1483 os_non_restarting_signal(SIGALRM, sigalrm_handler);
1491 smtp_cmd_buffer[ptr++] = c;
1494 receive_linecount++; /* For BSMTP errors */
1495 os_non_restarting_signal(SIGALRM, sigalrm_handler);
1497 /* If hit end of file, return pseudo EOF command. Whether we have a
1498 part-line already read doesn't matter, since this is an error state. */
1500 if (c == EOF) return EOF_CMD;
1502 /* Remove any CR and white space at the end of the line, and terminate the
1505 while (ptr > 0 && isspace(smtp_cmd_buffer[ptr-1])) ptr--;
1506 smtp_cmd_buffer[ptr] = 0;
1508 DEBUG(D_receive) debug_printf("SMTP<< %s\n", smtp_cmd_buffer);
1510 /* NULLs are not allowed in SMTP commands */
1512 if (hadnull) return BADCHAR_CMD;
1514 /* Scan command list and return identity, having set the data pointer
1515 to the start of the actual data characters. Check for SMTP synchronization
1518 for (p = cmd_list; p < cmd_list_end; p++)
1520 #ifdef SUPPORT_PROXY
1521 /* Only allow QUIT command if Proxy Protocol parsing failed */
1522 if (proxy_session && proxy_session_failed && p->cmd != QUIT_CMD)
1526 && strncmpic(smtp_cmd_buffer, US p->name, p->len) == 0
1527 && ( smtp_cmd_buffer[p->len-1] == ':' /* "mail from:" or "rcpt to:" */
1528 || smtp_cmd_buffer[p->len] == 0
1529 || smtp_cmd_buffer[p->len] == ' '
1532 if (smtp_inptr < smtp_inend && /* Outstanding input */
1533 p->cmd < sync_cmd_limit && /* Command should sync */
1534 check_sync && /* Local flag set */
1535 smtp_enforce_sync && /* Global flag set */
1536 sender_host_address != NULL && /* Not local input */
1537 !sender_host_notsocket) /* Really is a socket */
1540 /* The variables $smtp_command and $smtp_command_argument point into the
1541 unmodified input buffer. A copy of the latter is taken for actual
1542 processing, so that it can be chopped up into separate parts if necessary,
1543 for example, when processing a MAIL command options such as SIZE that can
1544 follow the sender address. */
1546 smtp_cmd_argument = smtp_cmd_buffer + p->len;
1547 while (isspace(*smtp_cmd_argument)) smtp_cmd_argument++;
1548 Ustrcpy(smtp_data_buffer, smtp_cmd_argument);
1549 smtp_cmd_data = smtp_data_buffer;
1551 /* Count non-mail commands from those hosts that are controlled in this
1552 way. The default is all hosts. We don't waste effort checking the list
1553 until we get a non-mail command, but then cache the result to save checking
1554 again. If there's a DEFER while checking the host, assume it's in the list.
1556 Note that one instance of RSET, EHLO/HELO, and STARTTLS is allowed at the
1557 start of each incoming message by fiddling with the value in the table. */
1559 if (!p->is_mail_cmd)
1561 if (count_nonmail == TRUE_UNSET) count_nonmail =
1562 verify_check_host(&smtp_accept_max_nonmail_hosts) != FAIL;
1563 if (count_nonmail && ++nonmail_command_count > smtp_accept_max_nonmail)
1564 return TOO_MANY_NONMAIL_CMD;
1567 /* If there is data for a command that does not expect it, generate the
1570 return (p->has_arg || *smtp_cmd_data == 0)? p->cmd : BADARG_CMD;
1574 #ifdef SUPPORT_PROXY
1575 /* Only allow QUIT command if Proxy Protocol parsing failed */
1576 if (proxy_session && proxy_session_failed)
1577 return PROXY_FAIL_IGNORE_CMD;
1580 /* Enforce synchronization for unknown commands */
1582 if (smtp_inptr < smtp_inend && /* Outstanding input */
1583 check_sync && /* Local flag set */
1584 smtp_enforce_sync && /* Global flag set */
1585 sender_host_address != NULL && /* Not local input */
1586 !sender_host_notsocket) /* Really is a socket */
1594 /*************************************************
1595 * Forced closedown of call *
1596 *************************************************/
1598 /* This function is called from log.c when Exim is dying because of a serious
1599 disaster, and also from some other places. If an incoming non-batched SMTP
1600 channel is open, it swallows the rest of the incoming message if in the DATA
1601 phase, sends the reply string, and gives an error to all subsequent commands
1602 except QUIT. The existence of an SMTP call is detected by the non-NULLness of
1606 message SMTP reply string to send, excluding the code
1612 smtp_closedown(uschar *message)
1614 if (smtp_in == NULL || smtp_batched_input) return;
1615 receive_swallow_smtp();
1616 smtp_printf("421 %s\r\n", message);
1618 for (;;) switch(smtp_read_command(FALSE, GETC_BUFFER_UNLIMITED))
1624 smtp_printf("221 %s closing connection\r\n", smtp_active_hostname);
1629 smtp_printf("250 Reset OK\r\n");
1633 smtp_printf("421 %s\r\n", message);
1641 /*************************************************
1642 * Set up connection info for logging *
1643 *************************************************/
1645 /* This function is called when logging information about an SMTP connection.
1646 It sets up appropriate source information, depending on the type of connection.
1647 If sender_fullhost is NULL, we are at a very early stage of the connection;
1648 just use the IP address.
1651 Returns: a string describing the connection
1655 smtp_get_connection_info(void)
1657 const uschar * hostname = sender_fullhost
1658 ? sender_fullhost : sender_host_address;
1661 return string_sprintf("SMTP connection from %s", hostname);
1663 if (sender_host_unknown || sender_host_notsocket)
1664 return string_sprintf("SMTP connection from %s", sender_ident);
1667 return string_sprintf("SMTP connection from %s (via inetd)", hostname);
1669 if (LOGGING(incoming_interface) && interface_address != NULL)
1670 return string_sprintf("SMTP connection from %s I=[%s]:%d", hostname,
1671 interface_address, interface_port);
1673 return string_sprintf("SMTP connection from %s", hostname);
1679 /* Append TLS-related information to a log line
1682 s String under construction: allocated string to extend, or NULL
1683 sizep Pointer to current allocation size (update on return), or NULL
1684 ptrp Pointer to index for new entries in string (update on return), or NULL
1686 Returns: Allocated string or NULL
1689 s_tlslog(uschar * s, int * sizep, int * ptrp)
1691 int size = sizep ? *sizep : 0;
1692 int ptr = ptrp ? *ptrp : 0;
1694 if (LOGGING(tls_cipher) && tls_in.cipher != NULL)
1695 s = string_append(s, &size, &ptr, 2, US" X=", tls_in.cipher);
1696 if (LOGGING(tls_certificate_verified) && tls_in.cipher != NULL)
1697 s = string_append(s, &size, &ptr, 2, US" CV=",
1698 tls_in.certificate_verified? "yes":"no");
1699 if (LOGGING(tls_peerdn) && tls_in.peerdn != NULL)
1700 s = string_append(s, &size, &ptr, 3, US" DN=\"",
1701 string_printing(tls_in.peerdn), US"\"");
1702 if (LOGGING(tls_sni) && tls_in.sni != NULL)
1703 s = string_append(s, &size, &ptr, 3, US" SNI=\"",
1704 string_printing(tls_in.sni), US"\"");
1709 if (sizep) *sizep = size;
1710 if (ptrp) *ptrp = ptr;
1716 /*************************************************
1717 * Log lack of MAIL if so configured *
1718 *************************************************/
1720 /* This function is called when an SMTP session ends. If the log selector
1721 smtp_no_mail is set, write a log line giving some details of what has happened
1722 in the SMTP session.
1729 smtp_log_no_mail(void)
1734 if (smtp_mailcmd_count > 0 || !LOGGING(smtp_no_mail))
1740 if (sender_host_authenticated != NULL)
1742 s = string_append(s, &size, &ptr, 2, US" A=", sender_host_authenticated);
1743 if (authenticated_id != NULL)
1744 s = string_append(s, &size, &ptr, 2, US":", authenticated_id);
1748 s = s_tlslog(s, &size, &ptr);
1751 sep = (smtp_connection_had[SMTP_HBUFF_SIZE-1] != SCH_NONE)?
1752 US" C=..." : US" C=";
1753 for (i = smtp_ch_index; i < SMTP_HBUFF_SIZE; i++)
1755 if (smtp_connection_had[i] != SCH_NONE)
1757 s = string_append(s, &size, &ptr, 2, sep,
1758 smtp_names[smtp_connection_had[i]]);
1763 for (i = 0; i < smtp_ch_index; i++)
1765 s = string_append(s, &size, &ptr, 2, sep, smtp_names[smtp_connection_had[i]]);
1769 if (s != NULL) s[ptr] = 0; else s = US"";
1770 log_write(0, LOG_MAIN, "no MAIL in SMTP connection from %s D=%s%s",
1771 host_and_ident(FALSE),
1772 readconf_printtime( (int) ((long)time(NULL) - (long)smtp_connection_start)),
1778 /*************************************************
1779 * Check HELO line and set sender_helo_name *
1780 *************************************************/
1782 /* Check the format of a HELO line. The data for HELO/EHLO is supposed to be
1783 the domain name of the sending host, or an ip literal in square brackets. The
1784 argument is placed in sender_helo_name, which is in malloc store, because it
1785 must persist over multiple incoming messages. If helo_accept_junk is set, this
1786 host is permitted to send any old junk (needed for some broken hosts).
1787 Otherwise, helo_allow_chars can be used for rogue characters in general
1788 (typically people want to let in underscores).
1791 s the data portion of the line (already past any white space)
1793 Returns: TRUE or FALSE
1797 check_helo(uschar *s)
1800 uschar *end = s + Ustrlen(s);
1801 BOOL yield = helo_accept_junk;
1803 /* Discard any previous helo name */
1805 if (sender_helo_name != NULL)
1807 store_free(sender_helo_name);
1808 sender_helo_name = NULL;
1811 /* Skip tests if junk is permitted. */
1815 /* Allow the new standard form for IPv6 address literals, namely,
1816 [IPv6:....], and because someone is bound to use it, allow an equivalent
1817 IPv4 form. Allow plain addresses as well. */
1824 if (strncmpic(s, US"[IPv6:", 6) == 0)
1825 yield = (string_is_ip_address(s+6, NULL) == 6);
1826 else if (strncmpic(s, US"[IPv4:", 6) == 0)
1827 yield = (string_is_ip_address(s+6, NULL) == 4);
1829 yield = (string_is_ip_address(s+1, NULL) != 0);
1834 /* Non-literals must be alpha, dot, hyphen, plus any non-valid chars
1835 that have been configured (usually underscore - sigh). */
1842 if (!isalnum(*s) && *s != '.' && *s != '-' &&
1843 Ustrchr(helo_allow_chars, *s) == NULL)
1853 /* Save argument if OK */
1855 if (yield) sender_helo_name = string_copy_malloc(start);
1863 /*************************************************
1864 * Extract SMTP command option *
1865 *************************************************/
1867 /* This function picks the next option setting off the end of smtp_cmd_data. It
1868 is called for MAIL FROM and RCPT TO commands, to pick off the optional ESMTP
1869 things that can appear there.
1872 name point this at the name
1873 value point this at the data string
1875 Returns: TRUE if found an option
1879 extract_option(uschar **name, uschar **value)
1882 uschar *v = smtp_cmd_data + Ustrlen(smtp_cmd_data) - 1;
1883 while (isspace(*v)) v--;
1885 while (v > smtp_cmd_data && *v != '=' && !isspace(*v))
1887 /* Take care to not stop at a space embedded in a quoted local-part */
1889 if (*v == '"') do v--; while (*v != '"' && v > smtp_cmd_data+1);
1896 while(isalpha(n[-1])) n--;
1897 /* RFC says SP, but TAB seen in wild and other major MTAs accept it */
1898 if (!isspace(n[-1])) return FALSE;
1904 if (v == smtp_cmd_data) return FALSE;
1916 /*************************************************
1917 * Reset for new message *
1918 *************************************************/
1920 /* This function is called whenever the SMTP session is reset from
1921 within either of the setup functions.
1923 Argument: the stacking pool storage reset point
1928 smtp_reset(void *reset_point)
1930 recipients_list = NULL;
1931 rcpt_count = rcpt_defer_count = rcpt_fail_count =
1932 raw_recipients_count = recipients_count = recipients_list_max = 0;
1933 message_linecount = 0;
1935 acl_added_headers = NULL;
1936 acl_removed_headers = NULL;
1937 queue_only_policy = FALSE;
1938 rcpt_smtp_response = NULL;
1939 rcpt_smtp_response_same = TRUE;
1940 rcpt_in_progress = FALSE;
1941 deliver_freeze = FALSE; /* Can be set by ACL */
1942 freeze_tell = freeze_tell_config; /* Can be set by ACL */
1943 fake_response = OK; /* Can be set by ACL */
1944 #ifdef WITH_CONTENT_SCAN
1945 no_mbox_unspool = FALSE; /* Can be set by ACL */
1947 submission_mode = FALSE; /* Can be set by ACL */
1948 suppress_local_fixups = suppress_local_fixups_default; /* Can be set by ACL */
1949 active_local_from_check = local_from_check; /* Can be set by ACL */
1950 active_local_sender_retain = local_sender_retain; /* Can be set by ACL */
1951 sending_ip_address = NULL;
1952 return_path = sender_address = NULL;
1953 sender_data = NULL; /* Can be set by ACL */
1954 deliver_localpart_orig = NULL;
1955 deliver_domain_orig = NULL;
1956 callout_address = NULL;
1957 submission_name = NULL; /* Can be set by ACL */
1958 raw_sender = NULL; /* After SMTP rewrite, before qualifying */
1959 sender_address_unrewritten = NULL; /* Set only after verify rewrite */
1960 sender_verified_list = NULL; /* No senders verified */
1961 memset(sender_address_cache, 0, sizeof(sender_address_cache));
1962 memset(sender_domain_cache, 0, sizeof(sender_domain_cache));
1964 authenticated_sender = NULL;
1965 #ifdef EXPERIMENTAL_BRIGHTMAIL
1967 bmi_verdicts = NULL;
1969 dnslist_domain = dnslist_matched = NULL;
1970 #ifndef DISABLE_DKIM
1971 dkim_signers = NULL;
1972 dkim_disable_verify = FALSE;
1973 dkim_collect_input = FALSE;
1977 deliver_host = deliver_host_address = NULL; /* Can be set by ACL */
1978 #ifndef DISABLE_PRDR
1979 prdr_requested = FALSE;
1981 #ifdef EXPERIMENTAL_SPF
1982 spf_header_comment = NULL;
1983 spf_received = NULL;
1985 spf_smtp_comment = NULL;
1988 message_smtputf8 = FALSE;
1990 body_linecount = body_zerocount = 0;
1992 sender_rate = sender_rate_limit = sender_rate_period = NULL;
1993 ratelimiters_mail = NULL; /* Updated by ratelimit ACL condition */
1994 /* Note that ratelimiters_conn persists across resets. */
1996 /* Reset message ACL variables */
2000 /* The message body variables use malloc store. They may be set if this is
2001 not the first message in an SMTP session and the previous message caused them
2002 to be referenced in an ACL. */
2006 store_free(message_body);
2007 message_body = NULL;
2010 if (message_body_end)
2012 store_free(message_body_end);
2013 message_body_end = NULL;
2016 /* Warning log messages are also saved in malloc store. They are saved to avoid
2017 repetition in the same message, but it seems right to repeat them for different
2020 while (acl_warn_logged)
2022 string_item *this = acl_warn_logged;
2023 acl_warn_logged = acl_warn_logged->next;
2026 store_reset(reset_point);
2033 /*************************************************
2034 * Initialize for incoming batched SMTP message *
2035 *************************************************/
2037 /* This function is called from smtp_setup_msg() in the case when
2038 smtp_batched_input is true. This happens when -bS is used to pass a whole batch
2039 of messages in one file with SMTP commands between them. All errors must be
2040 reported by sending a message, and only MAIL FROM, RCPT TO, and DATA are
2041 relevant. After an error on a sender, or an invalid recipient, the remainder
2042 of the message is skipped. The value of received_protocol is already set.
2045 Returns: > 0 message successfully started (reached DATA)
2046 = 0 QUIT read or end of file reached
2047 < 0 should not occur
2051 smtp_setup_batch_msg(void)
2054 void *reset_point = store_get(0);
2056 /* Save the line count at the start of each transaction - single commands
2057 like HELO and RSET count as whole transactions. */
2059 bsmtp_transaction_linecount = receive_linecount;
2061 if ((receive_feof)()) return 0; /* Treat EOF as QUIT */
2063 cancel_cutthrough_connection(TRUE, US"smtp_setup_batch_msg");
2064 smtp_reset(reset_point); /* Reset for start of message */
2066 /* Deal with SMTP commands. This loop is exited by setting done to a POSITIVE
2067 value. The values are 2 larger than the required yield of the function. */
2072 uschar *recipient = NULL;
2073 int start, end, sender_domain, recipient_domain;
2075 switch(smtp_read_command(FALSE, GETC_BUFFER_UNLIMITED))
2077 /* The HELO/EHLO commands set sender_address_helo if they have
2078 valid data; otherwise they are ignored, except that they do
2079 a reset of the state. */
2084 check_helo(smtp_cmd_data);
2088 cancel_cutthrough_connection(TRUE, US"RSET received");
2089 smtp_reset(reset_point);
2090 bsmtp_transaction_linecount = receive_linecount;
2094 /* The MAIL FROM command requires an address as an operand. All we
2095 do here is to parse it for syntactic correctness. The form "<>" is
2096 a special case which converts into an empty string. The start/end
2097 pointers in the original are not used further for this address, as
2098 it is the canonical extracted address which is all that is kept. */
2101 smtp_mailcmd_count++; /* Count for no-mail log */
2102 if (sender_address != NULL)
2103 /* The function moan_smtp_batch() does not return. */
2104 moan_smtp_batch(smtp_cmd_buffer, "503 Sender already given");
2106 if (smtp_cmd_data[0] == 0)
2107 /* The function moan_smtp_batch() does not return. */
2108 moan_smtp_batch(smtp_cmd_buffer, "501 MAIL FROM must have an address operand");
2110 /* Reset to start of message */
2112 cancel_cutthrough_connection(TRUE, US"MAIL received");
2113 smtp_reset(reset_point);
2115 /* Apply SMTP rewrite */
2117 raw_sender = ((rewrite_existflags & rewrite_smtp) != 0)?
2118 rewrite_one(smtp_cmd_data, rewrite_smtp|rewrite_smtp_sender, NULL, FALSE,
2119 US"", global_rewrite_rules) : smtp_cmd_data;
2121 /* Extract the address; the TRUE flag allows <> as valid */
2124 parse_extract_address(raw_sender, &errmess, &start, &end, &sender_domain,
2127 if (raw_sender == NULL)
2128 /* The function moan_smtp_batch() does not return. */
2129 moan_smtp_batch(smtp_cmd_buffer, "501 %s", errmess);
2131 sender_address = string_copy(raw_sender);
2133 /* Qualify unqualified sender addresses if permitted to do so. */
2135 if (sender_domain == 0 && sender_address[0] != 0 && sender_address[0] != '@')
2137 if (allow_unqualified_sender)
2139 sender_address = rewrite_address_qualify(sender_address, FALSE);
2140 DEBUG(D_receive) debug_printf("unqualified address %s accepted "
2141 "and rewritten\n", raw_sender);
2143 /* The function moan_smtp_batch() does not return. */
2144 else moan_smtp_batch(smtp_cmd_buffer, "501 sender address must contain "
2150 /* The RCPT TO command requires an address as an operand. All we do
2151 here is to parse it for syntactic correctness. There may be any number
2152 of RCPT TO commands, specifying multiple senders. We build them all into
2153 a data structure that is in argc/argv format. The start/end values
2154 given by parse_extract_address are not used, as we keep only the
2155 extracted address. */
2158 if (sender_address == NULL)
2159 /* The function moan_smtp_batch() does not return. */
2160 moan_smtp_batch(smtp_cmd_buffer, "503 No sender yet given");
2162 if (smtp_cmd_data[0] == 0)
2163 /* The function moan_smtp_batch() does not return. */
2164 moan_smtp_batch(smtp_cmd_buffer, "501 RCPT TO must have an address operand");
2166 /* Check maximum number allowed */
2168 if (recipients_max > 0 && recipients_count + 1 > recipients_max)
2169 /* The function moan_smtp_batch() does not return. */
2170 moan_smtp_batch(smtp_cmd_buffer, "%s too many recipients",
2171 recipients_max_reject? "552": "452");
2173 /* Apply SMTP rewrite, then extract address. Don't allow "<>" as a
2174 recipient address */
2176 recipient = rewrite_existflags & rewrite_smtp
2177 ? rewrite_one(smtp_cmd_data, rewrite_smtp, NULL, FALSE, US"",
2178 global_rewrite_rules)
2181 recipient = parse_extract_address(recipient, &errmess, &start, &end,
2182 &recipient_domain, FALSE);
2185 /* The function moan_smtp_batch() does not return. */
2186 moan_smtp_batch(smtp_cmd_buffer, "501 %s", errmess);
2188 /* If the recipient address is unqualified, qualify it if permitted. Then
2189 add it to the list of recipients. */
2191 if (recipient_domain == 0)
2193 if (allow_unqualified_recipient)
2195 DEBUG(D_receive) debug_printf("unqualified address %s accepted\n",
2197 recipient = rewrite_address_qualify(recipient, TRUE);
2199 /* The function moan_smtp_batch() does not return. */
2200 else moan_smtp_batch(smtp_cmd_buffer, "501 recipient address must contain "
2203 receive_add_recipient(recipient, -1);
2207 /* The DATA command is legal only if it follows successful MAIL FROM
2208 and RCPT TO commands. This function is complete when a valid DATA
2209 command is encountered. */
2212 if (sender_address == NULL || recipients_count <= 0)
2214 /* The function moan_smtp_batch() does not return. */
2215 if (sender_address == NULL)
2216 moan_smtp_batch(smtp_cmd_buffer,
2217 "503 MAIL FROM:<sender> command must precede DATA");
2219 moan_smtp_batch(smtp_cmd_buffer,
2220 "503 RCPT TO:<recipient> must precede DATA");
2224 done = 3; /* DATA successfully achieved */
2225 message_ended = END_NOTENDED; /* Indicate in middle of message */
2230 /* The VRFY, EXPN, HELP, ETRN, and NOOP commands are ignored. */
2237 bsmtp_transaction_linecount = receive_linecount;
2248 /* The function moan_smtp_batch() does not return. */
2249 moan_smtp_batch(smtp_cmd_buffer, "501 Unexpected argument data");
2254 /* The function moan_smtp_batch() does not return. */
2255 moan_smtp_batch(smtp_cmd_buffer, "501 Unexpected NULL in SMTP command");
2260 /* The function moan_smtp_batch() does not return. */
2261 moan_smtp_batch(smtp_cmd_buffer, "500 Command unrecognized");
2266 return done - 2; /* Convert yield values */
2273 smtp_log_tls_fail(uschar * errstr)
2275 uschar * conn_info = smtp_get_connection_info();
2277 if (Ustrncmp(conn_info, US"SMTP ", 5) == 0) conn_info += 5;
2278 /* I'd like to get separated H= here, but too hard for now */
2280 log_write(0, LOG_MAIN, "TLS error on %s %s", conn_info, errstr);
2285 /*************************************************
2286 * Start an SMTP session *
2287 *************************************************/
2289 /* This function is called at the start of an SMTP session. Thereafter,
2290 smtp_setup_msg() is called to initiate each separate message. This
2291 function does host-specific testing, and outputs the banner line.
2294 Returns: FALSE if the session can not continue; something has
2295 gone wrong, or the connection to the host is blocked
2299 smtp_start_session(void)
2303 uschar *user_msg, *log_msg;
2307 smtp_connection_start = time(NULL);
2308 for (smtp_ch_index = 0; smtp_ch_index < SMTP_HBUFF_SIZE; smtp_ch_index++)
2309 smtp_connection_had[smtp_ch_index] = SCH_NONE;
2312 /* Default values for certain variables */
2314 helo_seen = esmtp = helo_accept_junk = FALSE;
2315 smtp_mailcmd_count = 0;
2316 count_nonmail = TRUE_UNSET;
2317 synprot_error_count = unknown_command_count = nonmail_command_count = 0;
2318 smtp_delay_mail = smtp_rlm_base;
2319 auth_advertised = FALSE;
2320 pipelining_advertised = FALSE;
2321 pipelining_enable = TRUE;
2322 sync_cmd_limit = NON_SYNC_CMD_NON_PIPELINING;
2323 smtp_exit_function_called = FALSE; /* For avoiding loop in not-quit exit */
2325 /* If receiving by -bs from a trusted user, or testing with -bh, we allow
2326 authentication settings from -oMaa to remain in force. */
2328 if (!host_checking && !sender_host_notsocket) sender_host_authenticated = NULL;
2329 authenticated_by = NULL;
2332 tls_in.cipher = tls_in.peerdn = NULL;
2333 tls_in.ourcert = tls_in.peercert = NULL;
2335 tls_in.ocsp = OCSP_NOT_REQ;
2336 tls_advertised = FALSE;
2338 dsn_advertised = FALSE;
2340 smtputf8_advertised = FALSE;
2343 /* Reset ACL connection variables */
2347 /* Allow for trailing 0 in the command and data buffers. */
2349 if (!(smtp_cmd_buffer = US malloc(2*SMTP_CMD_BUFFER_SIZE + 2)))
2350 log_write(0, LOG_MAIN|LOG_PANIC_DIE,
2351 "malloc() failed for SMTP command buffer");
2353 smtp_cmd_buffer[0] = 0;
2354 smtp_data_buffer = smtp_cmd_buffer + SMTP_CMD_BUFFER_SIZE + 1;
2356 /* For batched input, the protocol setting can be overridden from the
2357 command line by a trusted caller. */
2359 if (smtp_batched_input)
2361 if (!received_protocol) received_protocol = US"local-bsmtp";
2364 /* For non-batched SMTP input, the protocol setting is forced here. It will be
2365 reset later if any of EHLO/AUTH/STARTTLS are received. */
2369 (sender_host_address ? protocols : protocols_local) [pnormal];
2371 /* Set up the buffer for inputting using direct read() calls, and arrange to
2372 call the local functions instead of the standard C ones. */
2374 if (!(smtp_inbuffer = (uschar *)malloc(IN_BUFFER_SIZE)))
2375 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "malloc() failed for SMTP input buffer");
2377 receive_getc = smtp_getc;
2378 receive_getbuf = smtp_getbuf;
2379 receive_get_cache = smtp_get_cache;
2380 receive_ungetc = smtp_ungetc;
2381 receive_feof = smtp_feof;
2382 receive_ferror = smtp_ferror;
2383 receive_smtp_buffered = smtp_buffered;
2384 smtp_inptr = smtp_inend = smtp_inbuffer;
2385 smtp_had_eof = smtp_had_error = 0;
2387 /* Set up the message size limit; this may be host-specific */
2389 thismessage_size_limit = expand_string_integer(message_size_limit, TRUE);
2390 if (expand_string_message != NULL)
2392 if (thismessage_size_limit == -1)
2393 log_write(0, LOG_MAIN|LOG_PANIC, "unable to expand message_size_limit: "
2394 "%s", expand_string_message);
2396 log_write(0, LOG_MAIN|LOG_PANIC, "invalid message_size_limit: "
2397 "%s", expand_string_message);
2398 smtp_closedown(US"Temporary local problem - please try later");
2402 /* When a message is input locally via the -bs or -bS options, sender_host_
2403 unknown is set unless -oMa was used to force an IP address, in which case it
2404 is checked like a real remote connection. When -bs is used from inetd, this
2405 flag is not set, causing the sending host to be checked. The code that deals
2406 with IP source routing (if configured) is never required for -bs or -bS and
2407 the flag sender_host_notsocket is used to suppress it.
2409 If smtp_accept_max and smtp_accept_reserve are set, keep some connections in
2410 reserve for certain hosts and/or networks. */
2412 if (!sender_host_unknown)
2415 BOOL reserved_host = FALSE;
2417 /* Look up IP options (source routing info) on the socket if this is not an
2418 -oMa "host", and if any are found, log them and drop the connection.
2420 Linux (and others now, see below) is different to everyone else, so there
2421 has to be some conditional compilation here. Versions of Linux before 2.1.15
2422 used a structure whose name was "options". Somebody finally realized that
2423 this name was silly, and it got changed to "ip_options". I use the
2424 newer name here, but there is a fudge in the script that sets up os.h
2425 to define a macro in older Linux systems.
2427 Sigh. Linux is a fast-moving target. Another generation of Linux uses
2428 glibc 2, which has chosen ip_opts for the structure name. This is now
2429 really a glibc thing rather than a Linux thing, so the condition name
2430 has been changed to reflect this. It is relevant also to GNU/Hurd.
2432 Mac OS 10.x (Darwin) is like the later glibc versions, but without the
2433 setting of the __GLIBC__ macro, so we can't detect it automatically. There's
2434 a special macro defined in the os.h file.
2436 Some DGUX versions on older hardware appear not to support IP options at
2437 all, so there is now a general macro which can be set to cut out this
2440 How to do this properly in IPv6 is not yet known. */
2442 #if !HAVE_IPV6 && !defined(NO_IP_OPTIONS)
2444 #ifdef GLIBC_IP_OPTIONS
2445 #if (!defined __GLIBC__) || (__GLIBC__ < 2)
2450 #elif defined DARWIN_IP_OPTIONS
2456 if (!host_checking && !sender_host_notsocket)
2459 EXIM_SOCKLEN_T optlen = sizeof(struct ip_options) + MAX_IPOPTLEN;
2460 struct ip_options *ipopt = store_get(optlen);
2462 struct ip_opts ipoptblock;
2463 struct ip_opts *ipopt = &ipoptblock;
2464 EXIM_SOCKLEN_T optlen = sizeof(ipoptblock);
2466 struct ipoption ipoptblock;
2467 struct ipoption *ipopt = &ipoptblock;
2468 EXIM_SOCKLEN_T optlen = sizeof(ipoptblock);
2471 /* Occasional genuine failures of getsockopt() have been seen - for
2472 example, "reset by peer". Therefore, just log and give up on this
2473 call, unless the error is ENOPROTOOPT. This error is given by systems
2474 that have the interfaces but not the mechanism - e.g. GNU/Hurd at the time
2475 of writing. So for that error, carry on - we just can't do an IP options
2478 DEBUG(D_receive) debug_printf("checking for IP options\n");
2480 if (getsockopt(fileno(smtp_out), IPPROTO_IP, IP_OPTIONS, (uschar *)(ipopt),
2483 if (errno != ENOPROTOOPT)
2485 log_write(0, LOG_MAIN, "getsockopt() failed from %s: %s",
2486 host_and_ident(FALSE), strerror(errno));
2487 smtp_printf("451 SMTP service not available\r\n");
2492 /* Deal with any IP options that are set. On the systems I have looked at,
2493 the value of MAX_IPOPTLEN has been 40, meaning that there should never be
2494 more logging data than will fit in big_buffer. Nevertheless, after somebody
2495 questioned this code, I've added in some paranoid checking. */
2497 else if (optlen > 0)
2499 uschar *p = big_buffer;
2500 uschar *pend = big_buffer + big_buffer_size;
2501 uschar *opt, *adptr;
2503 struct in_addr addr;
2506 uschar *optstart = (uschar *)(ipopt->__data);
2508 uschar *optstart = (uschar *)(ipopt->ip_opts);
2510 uschar *optstart = (uschar *)(ipopt->ipopt_list);
2513 DEBUG(D_receive) debug_printf("IP options exist\n");
2515 Ustrcpy(p, "IP options on incoming call:");
2518 for (opt = optstart; opt != NULL &&
2519 opt < (uschar *)(ipopt) + optlen;)
2533 if (!string_format(p, pend-p, " %s [@%s",
2534 (*opt == IPOPT_SSRR)? "SSRR" : "LSRR",
2536 inet_ntoa(*((struct in_addr *)(&(ipopt->faddr))))))
2538 inet_ntoa(ipopt->ip_dst)))
2540 inet_ntoa(ipopt->ipopt_dst)))
2548 optcount = (opt[1] - 3) / sizeof(struct in_addr);
2550 while (optcount-- > 0)
2552 memcpy(&addr, adptr, sizeof(addr));
2553 if (!string_format(p, pend - p - 1, "%s%s",
2554 (optcount == 0)? ":" : "@", inet_ntoa(addr)))
2560 adptr += sizeof(struct in_addr);
2569 if (pend - p < 4 + 3*opt[1]) { opt = NULL; break; }
2572 for (i = 0; i < opt[1]; i++)
2574 sprintf(CS p, "%2.2x ", opt[i]);
2585 log_write(0, LOG_MAIN, "%s", big_buffer);
2587 /* Refuse any call with IP options. This is what tcpwrappers 7.5 does. */
2589 log_write(0, LOG_MAIN|LOG_REJECT,
2590 "connection from %s refused (IP options)", host_and_ident(FALSE));
2592 smtp_printf("554 SMTP service not available\r\n");
2596 /* Length of options = 0 => there are no options */
2598 else DEBUG(D_receive) debug_printf("no IP options found\n");
2600 #endif /* HAVE_IPV6 && !defined(NO_IP_OPTIONS) */
2602 /* Set keep-alive in socket options. The option is on by default. This
2603 setting is an attempt to get rid of some hanging connections that stick in
2604 read() when the remote end (usually a dialup) goes away. */
2606 if (smtp_accept_keepalive && !sender_host_notsocket)
2607 ip_keepalive(fileno(smtp_out), sender_host_address, FALSE);
2609 /* If the current host matches host_lookup, set the name by doing a
2610 reverse lookup. On failure, sender_host_name will be NULL and
2611 host_lookup_failed will be TRUE. This may or may not be serious - optional
2614 if (verify_check_host(&host_lookup) == OK)
2616 (void)host_name_lookup();
2617 host_build_sender_fullhost();
2620 /* Delay this until we have the full name, if it is looked up. */
2622 set_process_info("handling incoming connection from %s",
2623 host_and_ident(FALSE));
2625 /* Expand smtp_receive_timeout, if needed */
2627 if (smtp_receive_timeout_s)
2630 if ( !(exp = expand_string(smtp_receive_timeout_s))
2632 || (smtp_receive_timeout = readconf_readtime(exp, 0, FALSE)) < 0
2634 log_write(0, LOG_MAIN|LOG_PANIC,
2635 "bad value for smtp_receive_timeout: '%s'", exp ? exp : US"");
2638 /* Test for explicit connection rejection */
2640 if (verify_check_host(&host_reject_connection) == OK)
2642 log_write(L_connection_reject, LOG_MAIN|LOG_REJECT, "refused connection "
2643 "from %s (host_reject_connection)", host_and_ident(FALSE));
2644 smtp_printf("554 SMTP service not available\r\n");
2648 /* Test with TCP Wrappers if so configured. There is a problem in that
2649 hosts_ctl() returns 0 (deny) under a number of system failure circumstances,
2650 such as disks dying. In these cases, it is desirable to reject with a 4xx
2651 error instead of a 5xx error. There isn't a "right" way to detect such
2652 problems. The following kludge is used: errno is zeroed before calling
2653 hosts_ctl(). If the result is "reject", a 5xx error is given only if the
2654 value of errno is 0 or ENOENT (which happens if /etc/hosts.{allow,deny} does
2657 #ifdef USE_TCP_WRAPPERS
2659 if (!(tcp_wrappers_name = expand_string(tcp_wrappers_daemon_name)))
2660 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "Expansion of \"%s\" "
2661 "(tcp_wrappers_name) failed: %s", string_printing(tcp_wrappers_name),
2662 expand_string_message);
2664 if (!hosts_ctl(tcp_wrappers_name,
2665 sender_host_name ? CS sender_host_name : STRING_UNKNOWN,
2666 sender_host_address ? CS sender_host_address : STRING_UNKNOWN,
2667 sender_ident ? CS sender_ident : STRING_UNKNOWN))
2669 if (errno == 0 || errno == ENOENT)
2671 HDEBUG(D_receive) debug_printf("tcp wrappers rejection\n");
2672 log_write(L_connection_reject,
2673 LOG_MAIN|LOG_REJECT, "refused connection from %s "
2674 "(tcp wrappers)", host_and_ident(FALSE));
2675 smtp_printf("554 SMTP service not available\r\n");
2679 int save_errno = errno;
2680 HDEBUG(D_receive) debug_printf("tcp wrappers rejected with unexpected "
2681 "errno value %d\n", save_errno);
2682 log_write(L_connection_reject,
2683 LOG_MAIN|LOG_REJECT, "temporarily refused connection from %s "
2684 "(tcp wrappers errno=%d)", host_and_ident(FALSE), save_errno);
2685 smtp_printf("451 Temporary local problem - please try later\r\n");
2691 /* Check for reserved slots. The value of smtp_accept_count has already been
2692 incremented to include this process. */
2694 if (smtp_accept_max > 0 &&
2695 smtp_accept_count > smtp_accept_max - smtp_accept_reserve)
2697 if ((rc = verify_check_host(&smtp_reserve_hosts)) != OK)
2699 log_write(L_connection_reject,
2700 LOG_MAIN, "temporarily refused connection from %s: not in "
2701 "reserve list: connected=%d max=%d reserve=%d%s",
2702 host_and_ident(FALSE), smtp_accept_count - 1, smtp_accept_max,
2703 smtp_accept_reserve, (rc == DEFER)? " (lookup deferred)" : "");
2704 smtp_printf("421 %s: Too many concurrent SMTP connections; "
2705 "please try again later\r\n", smtp_active_hostname);
2708 reserved_host = TRUE;
2711 /* If a load level above which only messages from reserved hosts are
2712 accepted is set, check the load. For incoming calls via the daemon, the
2713 check is done in the superior process if there are no reserved hosts, to
2714 save a fork. In all cases, the load average will already be available
2715 in a global variable at this point. */
2717 if (smtp_load_reserve >= 0 &&
2718 load_average > smtp_load_reserve &&
2720 verify_check_host(&smtp_reserve_hosts) != OK)
2722 log_write(L_connection_reject,
2723 LOG_MAIN, "temporarily refused connection from %s: not in "
2724 "reserve list and load average = %.2f", host_and_ident(FALSE),
2725 (double)load_average/1000.0);
2726 smtp_printf("421 %s: Too much load; please try again later\r\n",
2727 smtp_active_hostname);
2731 /* Determine whether unqualified senders or recipients are permitted
2732 for this host. Unfortunately, we have to do this every time, in order to
2733 set the flags so that they can be inspected when considering qualifying
2734 addresses in the headers. For a site that permits no qualification, this
2735 won't take long, however. */
2737 allow_unqualified_sender =
2738 verify_check_host(&sender_unqualified_hosts) == OK;
2740 allow_unqualified_recipient =
2741 verify_check_host(&recipient_unqualified_hosts) == OK;
2743 /* Determine whether HELO/EHLO is required for this host. The requirement
2744 can be hard or soft. */
2746 helo_required = verify_check_host(&helo_verify_hosts) == OK;
2748 helo_verify = verify_check_host(&helo_try_verify_hosts) == OK;
2750 /* Determine whether this hosts is permitted to send syntactic junk
2751 after a HELO or EHLO command. */
2753 helo_accept_junk = verify_check_host(&helo_accept_junk_hosts) == OK;
2756 /* For batch SMTP input we are now done. */
2758 if (smtp_batched_input) return TRUE;
2760 /* If valid Proxy Protocol source is connecting, set up session.
2761 * Failure will not allow any SMTP function other than QUIT. */
2763 #ifdef SUPPORT_PROXY
2764 proxy_session = FALSE;
2765 proxy_session_failed = FALSE;
2766 if (check_proxy_protocol_host())
2767 setup_proxy_protocol_host();
2770 /* Start up TLS if tls_on_connect is set. This is for supporting the legacy
2771 smtps port for use with older style SSL MTAs. */
2774 if (tls_in.on_connect && tls_server_start(tls_require_ciphers, &user_msg) != OK)
2775 return smtp_log_tls_fail(user_msg);
2778 /* Run the connect ACL if it exists */
2781 if (acl_smtp_connect)
2784 if ((rc = acl_check(ACL_WHERE_CONNECT, NULL, acl_smtp_connect, &user_msg,
2787 (void) smtp_handle_acl_fail(ACL_WHERE_CONNECT, rc, user_msg, log_msg);
2792 /* Output the initial message for a two-way SMTP connection. It may contain
2793 newlines, which then cause a multi-line response to be given. */
2795 code = US"220"; /* Default status code */
2796 esc = US""; /* Default extended status code */
2797 esclen = 0; /* Length of esc */
2801 if (!(s = expand_string(smtp_banner)))
2802 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "Expansion of \"%s\" (smtp_banner) "
2803 "failed: %s", smtp_banner, expand_string_message);
2809 smtp_message_code(&code, &codelen, &s, NULL, TRUE);
2813 esclen = codelen - 4;
2817 /* Remove any terminating newlines; might as well remove trailing space too */
2820 while (p > s && isspace(p[-1])) p--;
2823 /* It seems that CC:Mail is braindead, and assumes that the greeting message
2824 is all contained in a single IP packet. The original code wrote out the
2825 greeting using several calls to fprint/fputc, and on busy servers this could
2826 cause it to be split over more than one packet - which caused CC:Mail to fall
2827 over when it got the second part of the greeting after sending its first
2828 command. Sigh. To try to avoid this, build the complete greeting message
2829 first, and output it in one fell swoop. This gives a better chance of it
2830 ending up as a single packet. */
2832 ss = store_get(size);
2836 do /* At least once, in case we have an empty string */
2839 uschar *linebreak = Ustrchr(p, '\n');
2840 ss = string_catn(ss, &size, &ptr, code, 3);
2841 if (linebreak == NULL)
2844 ss = string_catn(ss, &size, &ptr, US" ", 1);
2848 len = linebreak - p;
2849 ss = string_catn(ss, &size, &ptr, US"-", 1);
2851 ss = string_catn(ss, &size, &ptr, esc, esclen);
2852 ss = string_catn(ss, &size, &ptr, p, len);
2853 ss = string_catn(ss, &size, &ptr, US"\r\n", 2);
2855 if (linebreak != NULL) p++;
2859 ss[ptr] = 0; /* string_cat leaves room for this */
2861 /* Before we write the banner, check that there is no input pending, unless
2862 this synchronisation check is disabled. */
2866 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP protocol "
2867 "synchronization error (input sent without waiting for greeting): "
2868 "rejected connection from %s input=\"%s\"", host_and_ident(TRUE),
2869 string_printing(smtp_inptr));
2870 smtp_printf("554 SMTP synchronization error\r\n");
2874 /* Now output the banner */
2876 smtp_printf("%s", ss);
2884 /*************************************************
2885 * Handle SMTP syntax and protocol errors *
2886 *************************************************/
2888 /* Write to the log for SMTP syntax errors in incoming commands, if configured
2889 to do so. Then transmit the error response. The return value depends on the
2890 number of syntax and protocol errors in this SMTP session.
2893 type error type, given as a log flag bit
2894 code response code; <= 0 means don't send a response
2895 data data to reflect in the response (can be NULL)
2896 errmess the error message
2898 Returns: -1 limit of syntax/protocol errors NOT exceeded
2899 +1 limit of syntax/protocol errors IS exceeded
2901 These values fit in with the values of the "done" variable in the main
2902 processing loop in smtp_setup_msg(). */
2905 synprot_error(int type, int code, uschar *data, uschar *errmess)
2909 log_write(type, LOG_MAIN, "SMTP %s error in \"%s\" %s %s",
2910 (type == L_smtp_syntax_error)? "syntax" : "protocol",
2911 string_printing(smtp_cmd_buffer), host_and_ident(TRUE), errmess);
2913 if (++synprot_error_count > smtp_max_synprot_errors)
2916 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
2917 "syntax or protocol errors (last command was \"%s\")",
2918 host_and_ident(FALSE), string_printing(smtp_cmd_buffer));
2923 smtp_printf("%d%c%s%s%s\r\n", code, (yield == 1)? '-' : ' ',
2924 (data == NULL)? US"" : data, (data == NULL)? US"" : US": ", errmess);
2926 smtp_printf("%d Too many syntax or protocol errors\r\n", code);
2935 /*************************************************
2936 * Send SMTP response, possibly multiline *
2937 *************************************************/
2939 /* There are, it seems, broken clients out there that cannot handle multiline
2940 responses. If no_multiline_responses is TRUE (it can be set from an ACL), we
2941 output nothing for non-final calls, and only the first line for anything else.
2944 code SMTP code, may involve extended status codes
2945 codelen length of smtp code; if > 4 there's an ESC
2946 final FALSE if the last line isn't the final line
2947 msg message text, possibly containing newlines
2953 smtp_respond(uschar* code, int codelen, BOOL final, uschar *msg)
2958 if (!final && no_multiline_responses) return;
2963 esclen = codelen - 4;
2966 /* If this is the first output for a (non-batch) RCPT command, see if all RCPTs
2967 have had the same. Note: this code is also present in smtp_printf(). It would
2968 be tidier to have it only in one place, but when it was added, it was easier to
2969 do it that way, so as not to have to mess with the code for the RCPT command,
2970 which sometimes uses smtp_printf() and sometimes smtp_respond(). */
2972 if (rcpt_in_progress)
2974 if (rcpt_smtp_response == NULL)
2975 rcpt_smtp_response = string_copy(msg);
2976 else if (rcpt_smtp_response_same &&
2977 Ustrcmp(rcpt_smtp_response, msg) != 0)
2978 rcpt_smtp_response_same = FALSE;
2979 rcpt_in_progress = FALSE;
2982 /* Not output the message, splitting it up into multiple lines if necessary. */
2986 uschar *nl = Ustrchr(msg, '\n');
2989 smtp_printf("%.3s%c%.*s%s\r\n", code, final? ' ':'-', esclen, esc, msg);
2992 else if (nl[1] == 0 || no_multiline_responses)
2994 smtp_printf("%.3s%c%.*s%.*s\r\n", code, final? ' ':'-', esclen, esc,
2995 (int)(nl - msg), msg);
3000 smtp_printf("%.3s-%.*s%.*s\r\n", code, esclen, esc, (int)(nl - msg), msg);
3002 while (isspace(*msg)) msg++;
3010 /*************************************************
3011 * Parse user SMTP message *
3012 *************************************************/
3014 /* This function allows for user messages overriding the response code details
3015 by providing a suitable response code string at the start of the message
3016 user_msg. Check the message for starting with a response code and optionally an
3017 extended status code. If found, check that the first digit is valid, and if so,
3018 change the code pointer and length to use the replacement. An invalid code
3019 causes a panic log; in this case, if the log messages is the same as the user
3020 message, we must also adjust the value of the log message to show the code that
3021 is actually going to be used (the original one).
3023 This function is global because it is called from receive.c as well as within
3026 Note that the code length returned includes the terminating whitespace
3027 character, which is always included in the regex match.
3030 code SMTP code, may involve extended status codes
3031 codelen length of smtp code; if > 4 there's an ESC
3033 log_msg optional log message, to be adjusted with the new SMTP code
3034 check_valid if true, verify the response code
3040 smtp_message_code(uschar **code, int *codelen, uschar **msg, uschar **log_msg,
3046 if (!msg || !*msg) return;
3048 if ((n = pcre_exec(regex_smtp_code, NULL, CS *msg, Ustrlen(*msg), 0,
3049 PCRE_EOPT, ovector, sizeof(ovector)/sizeof(int))) < 0) return;
3051 if (check_valid && (*msg)[0] != (*code)[0])
3053 log_write(0, LOG_MAIN|LOG_PANIC, "configured error code starts with "
3054 "incorrect digit (expected %c) in \"%s\"", (*code)[0], *msg);
3055 if (log_msg != NULL && *log_msg == *msg)
3056 *log_msg = string_sprintf("%s %s", *code, *log_msg + ovector[1]);
3061 *codelen = ovector[1]; /* Includes final space */
3063 *msg += ovector[1]; /* Chop the code off the message */
3070 /*************************************************
3071 * Handle an ACL failure *
3072 *************************************************/
3074 /* This function is called when acl_check() fails. As well as calls from within
3075 this module, it is called from receive.c for an ACL after DATA. It sorts out
3076 logging the incident, and sets up the error response. A message containing
3077 newlines is turned into a multiline SMTP response, but for logging, only the
3080 There's a table of default permanent failure response codes to use in
3081 globals.c, along with the table of names. VFRY is special. Despite RFC1123 it
3082 defaults disabled in Exim. However, discussion in connection with RFC 821bis
3083 (aka RFC 2821) has concluded that the response should be 252 in the disabled
3084 state, because there are broken clients that try VRFY before RCPT. A 5xx
3085 response should be given only when the address is positively known to be
3086 undeliverable. Sigh. We return 252 if there is no VRFY ACL or it provides
3087 no explicit code, but if there is one we let it know best.
3088 Also, for ETRN, 458 is given on refusal, and for AUTH, 503.
3090 From Exim 4.63, it is possible to override the response code details by
3091 providing a suitable response code string at the start of the message provided
3092 in user_msg. The code's first digit is checked for validity.
3095 where where the ACL was called from
3097 user_msg a message that can be included in an SMTP response
3098 log_msg a message for logging
3100 Returns: 0 in most cases
3101 2 if the failure code was FAIL_DROP, in which case the
3102 SMTP connection should be dropped (this value fits with the
3103 "done" variable in smtp_setup_msg() below)
3107 smtp_handle_acl_fail(int where, int rc, uschar *user_msg, uschar *log_msg)
3109 BOOL drop = rc == FAIL_DROP;
3113 uschar *sender_info = US"";
3115 #ifdef WITH_CONTENT_SCAN
3116 where == ACL_WHERE_MIME ? US"during MIME ACL checks" :
3118 where == ACL_WHERE_PREDATA ? US"DATA" :
3119 where == ACL_WHERE_DATA ? US"after DATA" :
3120 #ifndef DISABLE_PRDR
3121 where == ACL_WHERE_PRDR ? US"after DATA PRDR" :
3124 string_sprintf("%s %s", acl_wherenames[where], smtp_cmd_data) :
3125 string_sprintf("%s in \"connect\" ACL", acl_wherenames[where]);
3127 if (drop) rc = FAIL;
3129 /* Set the default SMTP code, and allow a user message to change it. */
3131 smtp_code = rc == FAIL ? acl_wherecodes[where] : US"451";
3132 smtp_message_code(&smtp_code, &codelen, &user_msg, &log_msg,
3133 where != ACL_WHERE_VRFY);
3135 /* We used to have sender_address here; however, there was a bug that was not
3136 updating sender_address after a rewrite during a verify. When this bug was
3137 fixed, sender_address at this point became the rewritten address. I'm not sure
3138 this is what should be logged, so I've changed to logging the unrewritten
3139 address to retain backward compatibility. */
3141 #ifndef WITH_CONTENT_SCAN
3142 if (where == ACL_WHERE_RCPT || where == ACL_WHERE_DATA)
3144 if (where == ACL_WHERE_RCPT || where == ACL_WHERE_DATA || where == ACL_WHERE_MIME)
3147 sender_info = string_sprintf("F=<%s>%s%s%s%s ",
3148 sender_address_unrewritten ? sender_address_unrewritten : sender_address,
3149 sender_host_authenticated ? US" A=" : US"",
3150 sender_host_authenticated ? sender_host_authenticated : US"",
3151 sender_host_authenticated && authenticated_id ? US":" : US"",
3152 sender_host_authenticated && authenticated_id ? authenticated_id : US""
3156 /* If there's been a sender verification failure with a specific message, and
3157 we have not sent a response about it yet, do so now, as a preliminary line for
3158 failures, but not defers. However, always log it for defer, and log it for fail
3159 unless the sender_verify_fail log selector has been turned off. */
3161 if (sender_verified_failed &&
3162 !testflag(sender_verified_failed, af_sverify_told))
3164 BOOL save_rcpt_in_progress = rcpt_in_progress;
3165 rcpt_in_progress = FALSE; /* So as not to treat these as the error */
3167 setflag(sender_verified_failed, af_sverify_told);
3169 if (rc != FAIL || LOGGING(sender_verify_fail))
3170 log_write(0, LOG_MAIN|LOG_REJECT, "%s sender verify %s for <%s>%s",
3171 host_and_ident(TRUE),
3172 ((sender_verified_failed->special_action & 255) == DEFER)? "defer":"fail",
3173 sender_verified_failed->address,
3174 (sender_verified_failed->message == NULL)? US"" :
3175 string_sprintf(": %s", sender_verified_failed->message));
3177 if (rc == FAIL && sender_verified_failed->user_message)
3178 smtp_respond(smtp_code, codelen, FALSE, string_sprintf(
3179 testflag(sender_verified_failed, af_verify_pmfail)?
3180 "Postmaster verification failed while checking <%s>\n%s\n"
3181 "Several RFCs state that you are required to have a postmaster\n"
3182 "mailbox for each mail domain. This host does not accept mail\n"
3183 "from domains whose servers reject the postmaster address."
3185 testflag(sender_verified_failed, af_verify_nsfail)?
3186 "Callback setup failed while verifying <%s>\n%s\n"
3187 "The initial connection, or a HELO or MAIL FROM:<> command was\n"
3188 "rejected. Refusing MAIL FROM:<> does not help fight spam, disregards\n"
3189 "RFC requirements, and stops you from receiving standard bounce\n"
3190 "messages. This host does not accept mail from domains whose servers\n"
3193 "Verification failed for <%s>\n%s",
3194 sender_verified_failed->address,
3195 sender_verified_failed->user_message));
3197 rcpt_in_progress = save_rcpt_in_progress;
3200 /* Sort out text for logging */
3202 log_msg = log_msg ? string_sprintf(": %s", log_msg) : US"";
3203 if ((lognl = Ustrchr(log_msg, '\n'))) *lognl = 0;
3205 /* Send permanent failure response to the command, but the code used isn't
3206 always a 5xx one - see comments at the start of this function. If the original
3207 rc was FAIL_DROP we drop the connection and yield 2. */
3210 smtp_respond(smtp_code, codelen, TRUE,
3211 user_msg ? user_msg : US"Administrative prohibition");
3213 /* Send temporary failure response to the command. Don't give any details,
3214 unless acl_temp_details is set. This is TRUE for a callout defer, a "defer"
3215 verb, and for a header verify when smtp_return_error_details is set.
3217 This conditional logic is all somewhat of a mess because of the odd
3218 interactions between temp_details and return_error_details. One day it should
3219 be re-implemented in a tidier fashion. */
3222 if (acl_temp_details && user_msg)
3224 if ( smtp_return_error_details
3225 && sender_verified_failed
3226 && sender_verified_failed->message
3228 smtp_respond(smtp_code, codelen, FALSE, sender_verified_failed->message);
3230 smtp_respond(smtp_code, codelen, TRUE, user_msg);
3233 smtp_respond(smtp_code, codelen, TRUE,
3234 US"Temporary local problem - please try later");
3236 /* Log the incident to the logs that are specified by log_reject_target
3237 (default main, reject). This can be empty to suppress logging of rejections. If
3238 the connection is not forcibly to be dropped, return 0. Otherwise, log why it
3239 is closing if required and return 2. */
3241 if (log_reject_target != 0)
3244 uschar * tls = s_tlslog(NULL, NULL, NULL);
3245 if (!tls) tls = US"";
3247 uschar * tls = US"";
3249 log_write(where == ACL_WHERE_CONNECT ? L_connection_reject : 0,
3250 log_reject_target, "%s%s%s %s%srejected %s%s",
3251 LOGGING(dnssec) && sender_host_dnssec ? US" DS" : US"",
3252 host_and_ident(TRUE),
3255 rc == FAIL ? US"" : US"temporarily ",
3259 if (!drop) return 0;
3261 log_write(L_smtp_connection, LOG_MAIN, "%s closed by DROP in ACL",
3262 smtp_get_connection_info());
3264 /* Run the not-quit ACL, but without any custom messages. This should not be a
3265 problem, because we get here only if some other ACL has issued "drop", and
3266 in that case, *its* custom messages will have been used above. */
3268 smtp_notquit_exit(US"acl-drop", NULL, NULL);
3275 /*************************************************
3276 * Handle SMTP exit when QUIT is not given *
3277 *************************************************/
3279 /* This function provides a logging/statistics hook for when an SMTP connection
3280 is dropped on the floor or the other end goes away. It's a global function
3281 because it's called from receive.c as well as this module. As well as running
3282 the NOTQUIT ACL, if there is one, this function also outputs a final SMTP
3283 response, either with a custom message from the ACL, or using a default. There
3284 is one case, however, when no message is output - after "drop". In that case,
3285 the ACL that obeyed "drop" has already supplied the custom message, and NULL is
3286 passed to this function.
3288 In case things go wrong while processing this function, causing an error that
3289 may re-enter this function, there is a recursion check.
3292 reason What $smtp_notquit_reason will be set to in the ACL;
3293 if NULL, the ACL is not run
3294 code The error code to return as part of the response
3295 defaultrespond The default message if there's no user_msg
3301 smtp_notquit_exit(uschar *reason, uschar *code, uschar *defaultrespond, ...)
3304 uschar *user_msg = NULL;
3305 uschar *log_msg = NULL;
3307 /* Check for recursive acll */
3309 if (smtp_exit_function_called)
3311 log_write(0, LOG_PANIC, "smtp_notquit_exit() called more than once (%s)",
3315 smtp_exit_function_called = TRUE;
3317 /* Call the not-QUIT ACL, if there is one, unless no reason is given. */
3319 if (acl_smtp_notquit && reason)
3321 smtp_notquit_reason = reason;
3322 if ((rc = acl_check(ACL_WHERE_NOTQUIT, NULL, acl_smtp_notquit, &user_msg,
3323 &log_msg)) == ERROR)
3324 log_write(0, LOG_MAIN|LOG_PANIC, "ACL for not-QUIT returned ERROR: %s",
3328 /* Write an SMTP response if we are expected to give one. As the default
3329 responses are all internal, they should always fit in the buffer, but code a
3330 warning, just in case. Note that string_vformat() still leaves a complete
3331 string, even if it is incomplete. */
3333 if (code && defaultrespond)
3336 smtp_respond(code, 3, TRUE, user_msg);
3341 va_start(ap, defaultrespond);
3342 if (!string_vformat(buffer, sizeof(buffer), CS defaultrespond, ap))
3343 log_write(0, LOG_MAIN|LOG_PANIC, "string too large in smtp_notquit_exit()");
3344 smtp_printf("%s %s\r\n", code, buffer);
3354 /*************************************************
3355 * Verify HELO argument *
3356 *************************************************/
3358 /* This function is called if helo_verify_hosts or helo_try_verify_hosts is
3359 matched. It is also called from ACL processing if verify = helo is used and
3360 verification was not previously tried (i.e. helo_try_verify_hosts was not
3361 matched). The result of its processing is to set helo_verified and
3362 helo_verify_failed. These variables should both be FALSE for this function to
3365 Note that EHLO/HELO is legitimately allowed to quote an address literal. Allow
3366 for IPv6 ::ffff: literals.
3369 Returns: TRUE if testing was completed;
3370 FALSE on a temporary failure
3374 smtp_verify_helo(void)
3378 HDEBUG(D_receive) debug_printf("verifying EHLO/HELO argument \"%s\"\n",
3381 if (sender_helo_name == NULL)
3383 HDEBUG(D_receive) debug_printf("no EHLO/HELO command was issued\n");
3386 /* Deal with the case of -bs without an IP address */
3388 else if (sender_host_address == NULL)
3390 HDEBUG(D_receive) debug_printf("no client IP address: assume success\n");
3391 helo_verified = TRUE;
3394 /* Deal with the more common case when there is a sending IP address */
3396 else if (sender_helo_name[0] == '[')
3398 helo_verified = Ustrncmp(sender_helo_name+1, sender_host_address,
3399 Ustrlen(sender_host_address)) == 0;
3404 if (strncmpic(sender_host_address, US"::ffff:", 7) == 0)
3405 helo_verified = Ustrncmp(sender_helo_name + 1,
3406 sender_host_address + 7, Ustrlen(sender_host_address) - 7) == 0;
3411 { if (helo_verified) debug_printf("matched host address\n"); }
3414 /* Do a reverse lookup if one hasn't already given a positive or negative
3415 response. If that fails, or the name doesn't match, try checking with a forward
3420 if (sender_host_name == NULL && !host_lookup_failed)
3421 yield = host_name_lookup() != DEFER;
3423 /* If a host name is known, check it and all its aliases. */
3425 if (sender_host_name)
3426 if ((helo_verified = strcmpic(sender_host_name, sender_helo_name) == 0))
3428 sender_helo_dnssec = sender_host_dnssec;
3429 HDEBUG(D_receive) debug_printf("matched host name\n");
3433 uschar **aliases = sender_host_aliases;
3435 if ((helo_verified = strcmpic(*aliases++, sender_helo_name) == 0))
3437 sender_helo_dnssec = sender_host_dnssec;
3441 HDEBUG(D_receive) if (helo_verified)
3442 debug_printf("matched alias %s\n", *(--aliases));
3445 /* Final attempt: try a forward lookup of the helo name */
3454 h.name = sender_helo_name;
3461 HDEBUG(D_receive) debug_printf("getting IP address for %s\n",
3463 rc = host_find_bydns(&h, NULL, HOST_FIND_BY_A,
3464 NULL, NULL, NULL, &d, NULL, NULL);
3465 if (rc == HOST_FOUND || rc == HOST_FOUND_LOCAL)
3466 for (hh = &h; hh; hh = hh->next)
3467 if (Ustrcmp(hh->address, sender_host_address) == 0)
3469 helo_verified = TRUE;
3470 if (h.dnssec == DS_YES) sender_helo_dnssec = TRUE;
3473 debug_printf("IP address for %s matches calling address\n"
3474 "Forward DNS security status: %sverified\n",
3475 sender_helo_name, sender_helo_dnssec ? "" : "un");
3482 if (!helo_verified) helo_verify_failed = TRUE; /* We've tried ... */
3489 /*************************************************
3490 * Send user response message *
3491 *************************************************/
3493 /* This function is passed a default response code and a user message. It calls
3494 smtp_message_code() to check and possibly modify the response code, and then
3495 calls smtp_respond() to transmit the response. I put this into a function
3496 just to avoid a lot of repetition.
3499 code the response code
3500 user_msg the user message
3506 smtp_user_msg(uschar *code, uschar *user_msg)
3509 smtp_message_code(&code, &len, &user_msg, NULL, TRUE);
3510 smtp_respond(code, len, TRUE, user_msg);
3516 smtp_in_auth(auth_instance *au, uschar ** s, uschar ** ss)
3518 const uschar *set_id = NULL;
3521 /* Run the checking code, passing the remainder of the command line as
3522 data. Initials the $auth<n> variables as empty. Initialize $0 empty and set
3523 it as the only set numerical variable. The authenticator may set $auth<n>
3524 and also set other numeric variables. The $auth<n> variables are preferred
3525 nowadays; the numerical variables remain for backwards compatibility.
3527 Afterwards, have a go at expanding the set_id string, even if
3528 authentication failed - for bad passwords it can be useful to log the
3529 userid. On success, require set_id to expand and exist, and put it in
3530 authenticated_id. Save this in permanent store, as the working store gets
3531 reset at HELO, RSET, etc. */
3533 for (i = 0; i < AUTH_VARS; i++) auth_vars[i] = NULL;
3535 expand_nlength[0] = 0; /* $0 contains nothing */
3537 rc = (au->info->servercode)(au, smtp_cmd_data);
3538 if (au->set_id) set_id = expand_string(au->set_id);
3539 expand_nmax = -1; /* Reset numeric variables */
3540 for (i = 0; i < AUTH_VARS; i++) auth_vars[i] = NULL; /* Reset $auth<n> */
3542 /* The value of authenticated_id is stored in the spool file and printed in
3543 log lines. It must not contain binary zeros or newline characters. In
3544 normal use, it never will, but when playing around or testing, this error
3545 can (did) happen. To guard against this, ensure that the id contains only
3546 printing characters. */
3548 if (set_id) set_id = string_printing(set_id);
3550 /* For the non-OK cases, set up additional logging data if set_id
3554 set_id = set_id && *set_id
3555 ? string_sprintf(" (set_id=%s)", set_id) : US"";
3557 /* Switch on the result */
3562 if (!au->set_id || set_id) /* Complete success */
3564 if (set_id) authenticated_id = string_copy_malloc(set_id);
3565 sender_host_authenticated = au->name;
3566 authentication_failed = FALSE;
3567 authenticated_fail_id = NULL; /* Impossible to already be set? */
3570 (sender_host_address ? protocols : protocols_local)
3571 [pextend + pauthed + (tls_in.active >= 0 ? pcrpted:0)];
3572 *s = *ss = US"235 Authentication succeeded";
3573 authenticated_by = au;
3577 /* Authentication succeeded, but we failed to expand the set_id string.
3578 Treat this as a temporary error. */
3580 auth_defer_msg = expand_string_message;
3584 if (set_id) authenticated_fail_id = string_copy_malloc(set_id);
3585 *s = string_sprintf("435 Unable to authenticate at present%s",
3586 auth_defer_user_msg);
3587 *ss = string_sprintf("435 Unable to authenticate at present%s: %s",
3588 set_id, auth_defer_msg);
3592 *s = *ss = US"501 Invalid base64 data";
3596 *s = *ss = US"501 Authentication cancelled";
3600 *s = *ss = US"553 Initial data not expected";
3604 if (set_id) authenticated_fail_id = string_copy_malloc(set_id);
3605 *s = US"535 Incorrect authentication data";
3606 *ss = string_sprintf("535 Incorrect authentication data%s", set_id);
3610 if (set_id) authenticated_fail_id = string_copy_malloc(set_id);
3611 *s = US"435 Internal error";
3612 *ss = string_sprintf("435 Internal error%s: return %d from authentication "
3613 "check", set_id, rc);
3625 qualify_recipient(uschar ** recipient, uschar * smtp_cmd_data, uschar * tag)
3628 if (allow_unqualified_recipient || strcmpic(*recipient, US"postmaster") == 0)
3630 DEBUG(D_receive) debug_printf("unqualified address %s accepted\n",
3632 rd = Ustrlen(recipient) + 1;
3633 *recipient = rewrite_address_qualify(*recipient, TRUE);
3636 smtp_printf("501 %s: recipient address must contain a domain\r\n",
3638 log_write(L_smtp_syntax_error,
3639 LOG_MAIN|LOG_REJECT, "unqualified %s rejected: <%s> %s%s",
3640 tag, *recipient, host_and_ident(TRUE), host_lookup_msg);
3648 smtp_quit_handler(uschar ** user_msgp, uschar ** log_msgp)
3651 incomplete_transaction_log(US"QUIT");
3654 int rc = acl_check(ACL_WHERE_QUIT, NULL, acl_smtp_quit, user_msgp, log_msgp);
3656 log_write(0, LOG_MAIN|LOG_PANIC, "ACL for QUIT returned ERROR: %s",
3660 smtp_respond(US"221", 3, TRUE, *user_msgp);
3662 smtp_printf("221 %s closing connection\r\n", smtp_active_hostname);
3665 tls_close(TRUE, TRUE);
3668 log_write(L_smtp_connection, LOG_MAIN, "%s closed by QUIT",
3669 smtp_get_connection_info());
3674 smtp_rset_handler(void)
3677 incomplete_transaction_log(US"RSET");
3678 smtp_printf("250 Reset OK\r\n");
3679 cmd_list[CMD_LIST_RSET].is_mail_cmd = FALSE;
3684 /*************************************************
3685 * Initialize for SMTP incoming message *
3686 *************************************************/
3688 /* This function conducts the initial dialogue at the start of an incoming SMTP
3689 message, and builds a list of recipients. However, if the incoming message
3690 is part of a batch (-bS option) a separate function is called since it would
3691 be messy having tests splattered about all over this function. This function
3692 therefore handles the case where interaction is occurring. The input and output
3693 files are set up in smtp_in and smtp_out.
3695 The global recipients_list is set to point to a vector of recipient_item
3696 blocks, whose number is given by recipients_count. This is extended by the
3697 receive_add_recipient() function. The global variable sender_address is set to
3698 the sender's address. The yield is +1 if a message has been successfully
3699 started, 0 if a QUIT command was encountered or the connection was refused from
3700 the particular host, or -1 if the connection was lost.
3704 Returns: > 0 message successfully started (reached DATA)
3705 = 0 QUIT read or end of file reached or call refused
3710 smtp_setup_msg(void)
3713 BOOL toomany = FALSE;
3714 BOOL discarded = FALSE;
3715 BOOL last_was_rej_mail = FALSE;
3716 BOOL last_was_rcpt = FALSE;
3717 void *reset_point = store_get(0);
3719 DEBUG(D_receive) debug_printf("smtp_setup_msg entered\n");
3721 /* Reset for start of new message. We allow one RSET not to be counted as a
3722 nonmail command, for those MTAs that insist on sending it between every
3723 message. Ditto for EHLO/HELO and for STARTTLS, to allow for going in and out of
3724 TLS between messages (an Exim client may do this if it has messages queued up
3725 for the host). Note: we do NOT reset AUTH at this point. */
3727 smtp_reset(reset_point);
3728 message_ended = END_NOTSTARTED;
3730 chunking_state = chunking_offered ? CHUNKING_OFFERED : CHUNKING_NOT_OFFERED;
3732 cmd_list[CMD_LIST_RSET].is_mail_cmd = TRUE;
3733 cmd_list[CMD_LIST_HELO].is_mail_cmd = TRUE;
3734 cmd_list[CMD_LIST_EHLO].is_mail_cmd = TRUE;
3736 cmd_list[CMD_LIST_STARTTLS].is_mail_cmd = TRUE;
3737 cmd_list[CMD_LIST_TLS_AUTH].is_mail_cmd = TRUE;
3740 /* Set the local signal handler for SIGTERM - it tries to end off tidily */
3742 os_non_restarting_signal(SIGTERM, command_sigterm_handler);
3744 /* Batched SMTP is handled in a different function. */
3746 if (smtp_batched_input) return smtp_setup_batch_msg();
3748 /* Deal with SMTP commands. This loop is exited by setting done to a POSITIVE
3749 value. The values are 2 larger than the required yield of the function. */
3753 const uschar **argv;
3754 uschar *etrn_command;
3755 uschar *etrn_serialize_key;
3757 uschar *log_msg, *smtp_code;
3758 uschar *user_msg = NULL;
3759 uschar *recipient = NULL;
3760 uschar *hello = NULL;
3762 BOOL was_rej_mail = FALSE;
3763 BOOL was_rcpt = FALSE;
3764 void (*oldsignal)(int);
3766 int start, end, sender_domain, recipient_domain;
3770 uschar *orcpt = NULL;
3774 /* Check once per STARTTLS or SSL-on-connect for a TLS AUTH */
3775 if ( tls_in.active >= 0
3777 && tls_in.certificate_verified
3778 && cmd_list[CMD_LIST_TLS_AUTH].is_mail_cmd
3781 cmd_list[CMD_LIST_TLS_AUTH].is_mail_cmd = FALSE;
3783 && (rc = acl_check(ACL_WHERE_AUTH, NULL, acl_smtp_auth,
3784 &user_msg, &log_msg)) != OK
3787 done = smtp_handle_acl_fail(ACL_WHERE_AUTH, rc, user_msg, log_msg);
3791 for (au = auths; au; au = au->next)
3792 if (strcmpic(US"tls", au->driver_name) == 0)
3794 smtp_cmd_data = NULL;
3796 if (smtp_in_auth(au, &s, &ss) == OK)
3797 { DEBUG(D_auth) debug_printf("tls auth succeeded\n"); }
3799 { DEBUG(D_auth) debug_printf("tls auth not succeeded\n"); }
3806 if (smtp_in) /* Avoid pure-ACKs while in cmd pingpong phase */
3807 (void) setsockopt(fileno(smtp_in), IPPROTO_TCP, TCP_QUICKACK,
3808 US &off, sizeof(off));
3811 switch(smtp_read_command(TRUE, GETC_BUFFER_UNLIMITED))
3813 /* The AUTH command is not permitted to occur inside a transaction, and may
3814 occur successfully only once per connection. Actually, that isn't quite
3815 true. When TLS is started, all previous information about a connection must
3816 be discarded, so a new AUTH is permitted at that time.
3818 AUTH may only be used when it has been advertised. However, it seems that
3819 there are clients that send AUTH when it hasn't been advertised, some of
3820 them even doing this after HELO. And there are MTAs that accept this. Sigh.
3821 So there's a get-out that allows this to happen.
3823 AUTH is initially labelled as a "nonmail command" so that one occurrence
3824 doesn't get counted. We change the label here so that multiple failing
3825 AUTHS will eventually hit the nonmail threshold. */
3829 authentication_failed = TRUE;
3830 cmd_list[CMD_LIST_AUTH].is_mail_cmd = FALSE;
3832 if (!auth_advertised && !allow_auth_unadvertised)
3834 done = synprot_error(L_smtp_protocol_error, 503, NULL,
3835 US"AUTH command used when not advertised");
3838 if (sender_host_authenticated)
3840 done = synprot_error(L_smtp_protocol_error, 503, NULL,
3841 US"already authenticated");
3846 done = synprot_error(L_smtp_protocol_error, 503, NULL,
3847 US"not permitted in mail transaction");
3854 && (rc = acl_check(ACL_WHERE_AUTH, NULL, acl_smtp_auth,
3855 &user_msg, &log_msg)) != OK
3858 done = smtp_handle_acl_fail(ACL_WHERE_AUTH, rc, user_msg, log_msg);
3862 /* Find the name of the requested authentication mechanism. */
3865 while ((c = *smtp_cmd_data) != 0 && !isspace(c))
3867 if (!isalnum(c) && c != '-' && c != '_')
3869 done = synprot_error(L_smtp_syntax_error, 501, NULL,
3870 US"invalid character in authentication mechanism name");
3876 /* If not at the end of the line, we must be at white space. Terminate the
3877 name and move the pointer on to any data that may be present. */
3879 if (*smtp_cmd_data != 0)
3881 *smtp_cmd_data++ = 0;
3882 while (isspace(*smtp_cmd_data)) smtp_cmd_data++;
3885 /* Search for an authentication mechanism which is configured for use
3886 as a server and which has been advertised (unless, sigh, allow_auth_
3887 unadvertised is set). */
3889 for (au = auths; au; au = au->next)
3890 if (strcmpic(s, au->public_name) == 0 && au->server &&
3891 (au->advertised || allow_auth_unadvertised))
3896 c = smtp_in_auth(au, &s, &ss);
3898 smtp_printf("%s\r\n", s);
3900 log_write(0, LOG_MAIN|LOG_REJECT, "%s authenticator failed for %s: %s",
3901 au->name, host_and_ident(FALSE), ss);
3904 done = synprot_error(L_smtp_protocol_error, 504, NULL,
3905 string_sprintf("%s authentication mechanism not supported", s));
3907 break; /* AUTH_CMD */
3909 /* The HELO/EHLO commands are permitted to appear in the middle of a
3910 session as well as at the beginning. They have the effect of a reset in
3911 addition to their other functions. Their absence at the start cannot be
3912 taken to be an error.
3916 If the EHLO command is not acceptable to the SMTP server, 501, 500,
3917 or 502 failure replies MUST be returned as appropriate. The SMTP
3918 server MUST stay in the same state after transmitting these replies
3919 that it was in before the EHLO was received.
3921 Therefore, we do not do the reset until after checking the command for
3922 acceptability. This change was made for Exim release 4.11. Previously
3923 it did the reset first. */
3936 HELO_EHLO: /* Common code for HELO and EHLO */
3937 cmd_list[CMD_LIST_HELO].is_mail_cmd = FALSE;
3938 cmd_list[CMD_LIST_EHLO].is_mail_cmd = FALSE;
3940 /* Reject the HELO if its argument was invalid or non-existent. A
3941 successful check causes the argument to be saved in malloc store. */
3943 if (!check_helo(smtp_cmd_data))
3945 smtp_printf("501 Syntactically invalid %s argument(s)\r\n", hello);
3947 log_write(0, LOG_MAIN|LOG_REJECT, "rejected %s from %s: syntactically "
3948 "invalid argument(s): %s", hello, host_and_ident(FALSE),
3949 (*smtp_cmd_argument == 0)? US"(no argument given)" :
3950 string_printing(smtp_cmd_argument));
3952 if (++synprot_error_count > smtp_max_synprot_errors)
3954 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
3955 "syntax or protocol errors (last command was \"%s\")",
3956 host_and_ident(FALSE), string_printing(smtp_cmd_buffer));
3963 /* If sender_host_unknown is true, we have got here via the -bs interface,
3964 not called from inetd. Otherwise, we are running an IP connection and the
3965 host address will be set. If the helo name is the primary name of this
3966 host and we haven't done a reverse lookup, force one now. If helo_required
3967 is set, ensure that the HELO name matches the actual host. If helo_verify
3968 is set, do the same check, but softly. */
3970 if (!sender_host_unknown)
3972 BOOL old_helo_verified = helo_verified;
3973 uschar *p = smtp_cmd_data;
3975 while (*p != 0 && !isspace(*p)) { *p = tolower(*p); p++; }
3978 /* Force a reverse lookup if HELO quoted something in helo_lookup_domains
3979 because otherwise the log can be confusing. */
3981 if (sender_host_name == NULL &&
3982 (deliver_domain = sender_helo_name, /* set $domain */
3983 match_isinlist(sender_helo_name, CUSS &helo_lookup_domains, 0,
3984 &domainlist_anchor, NULL, MCL_DOMAIN, TRUE, NULL)) == OK)
3985 (void)host_name_lookup();
3987 /* Rebuild the fullhost info to include the HELO name (and the real name
3988 if it was looked up.) */
3990 host_build_sender_fullhost(); /* Rebuild */
3991 set_process_info("handling%s incoming connection from %s",
3992 (tls_in.active >= 0)? " TLS" : "", host_and_ident(FALSE));
3994 /* Verify if configured. This doesn't give much security, but it does
3995 make some people happy to be able to do it. If helo_required is set,
3996 (host matches helo_verify_hosts) failure forces rejection. If helo_verify
3997 is set (host matches helo_try_verify_hosts), it does not. This is perhaps
3998 now obsolescent, since the verification can now be requested selectively
4001 helo_verified = helo_verify_failed = sender_helo_dnssec = FALSE;
4002 if (helo_required || helo_verify)
4004 BOOL tempfail = !smtp_verify_helo();
4009 smtp_printf("%d %s argument does not match calling host\r\n",
4010 tempfail? 451 : 550, hello);
4011 log_write(0, LOG_MAIN|LOG_REJECT, "%srejected \"%s %s\" from %s",
4012 tempfail? "temporarily " : "",
4013 hello, sender_helo_name, host_and_ident(FALSE));
4014 helo_verified = old_helo_verified;
4015 break; /* End of HELO/EHLO processing */
4017 HDEBUG(D_all) debug_printf("%s verification failed but host is in "
4018 "helo_try_verify_hosts\n", hello);
4023 #ifdef EXPERIMENTAL_SPF
4024 /* set up SPF context */
4025 spf_init(sender_helo_name, sender_host_address);
4028 /* Apply an ACL check if one is defined; afterwards, recheck
4029 synchronization in case the client started sending in a delay. */
4032 if ((rc = acl_check(ACL_WHERE_HELO, NULL, acl_smtp_helo,
4033 &user_msg, &log_msg)) != OK)
4035 done = smtp_handle_acl_fail(ACL_WHERE_HELO, rc, user_msg, log_msg);
4036 sender_helo_name = NULL;
4037 host_build_sender_fullhost(); /* Rebuild */
4040 else if (!check_sync()) goto SYNC_FAILURE;
4042 /* Generate an OK reply. The default string includes the ident if present,
4043 and also the IP address if present. Reflecting back the ident is intended
4044 as a deterrent to mail forgers. For maximum efficiency, and also because
4045 some broken systems expect each response to be in a single packet, arrange
4046 that the entire reply is sent in one write(). */
4048 auth_advertised = FALSE;
4049 pipelining_advertised = FALSE;
4051 tls_advertised = FALSE;
4053 dsn_advertised = FALSE;
4055 smtputf8_advertised = FALSE;
4058 smtp_code = US"250 "; /* Default response code plus space*/
4059 if (user_msg == NULL)
4061 s = string_sprintf("%.3s %s Hello %s%s%s",
4063 smtp_active_hostname,
4064 (sender_ident == NULL)? US"" : sender_ident,
4065 (sender_ident == NULL)? US"" : US" at ",
4066 (sender_host_name == NULL)? sender_helo_name : sender_host_name);
4071 if (sender_host_address != NULL)
4073 s = string_catn(s, &size, &ptr, US" [", 2);
4074 s = string_cat (s, &size, &ptr, sender_host_address);
4075 s = string_catn(s, &size, &ptr, US"]", 1);
4079 /* A user-supplied EHLO greeting may not contain more than one line. Note
4080 that the code returned by smtp_message_code() includes the terminating
4081 whitespace character. */
4087 smtp_message_code(&smtp_code, &codelen, &user_msg, NULL, TRUE);
4088 s = string_sprintf("%.*s%s", codelen, smtp_code, user_msg);
4089 if ((ss = strpbrk(CS s, "\r\n")) != NULL)
4091 log_write(0, LOG_MAIN|LOG_PANIC, "EHLO/HELO response must not contain "
4092 "newlines: message truncated: %s", string_printing(s));
4099 s = string_catn(s, &size, &ptr, US"\r\n", 2);
4101 /* If we received EHLO, we must create a multiline response which includes
4102 the functions supported. */
4108 /* I'm not entirely happy with this, as an MTA is supposed to check
4109 that it has enough room to accept a message of maximum size before
4110 it sends this. However, there seems little point in not sending it.
4111 The actual size check happens later at MAIL FROM time. By postponing it
4112 till then, VRFY and EXPN can be used after EHLO when space is short. */
4114 if (thismessage_size_limit > 0)
4116 sprintf(CS big_buffer, "%.3s-SIZE %d\r\n", smtp_code,
4117 thismessage_size_limit);
4118 s = string_cat(s, &size, &ptr, big_buffer);
4122 s = string_catn(s, &size, &ptr, smtp_code, 3);
4123 s = string_catn(s, &size, &ptr, US"-SIZE\r\n", 7);
4126 /* Exim does not do protocol conversion or data conversion. It is 8-bit
4127 clean; if it has an 8-bit character in its hand, it just sends it. It
4128 cannot therefore specify 8BITMIME and remain consistent with the RFCs.
4129 However, some users want this option simply in order to stop MUAs
4130 mangling messages that contain top-bit-set characters. It is therefore
4131 provided as an option. */
4133 if (accept_8bitmime)
4135 s = string_catn(s, &size, &ptr, smtp_code, 3);
4136 s = string_catn(s, &size, &ptr, US"-8BITMIME\r\n", 11);
4139 /* Advertise DSN support if configured to do so. */
4140 if (verify_check_host(&dsn_advertise_hosts) != FAIL)
4142 s = string_catn(s, &size, &ptr, smtp_code, 3);
4143 s = string_catn(s, &size, &ptr, US"-DSN\r\n", 6);
4144 dsn_advertised = TRUE;
4147 /* Advertise ETRN/VRFY/EXPN if there's are ACL checking whether a host is
4148 permitted to issue them; a check is made when any host actually tries. */
4152 s = string_catn(s, &size, &ptr, smtp_code, 3);
4153 s = string_catn(s, &size, &ptr, US"-ETRN\r\n", 7);
4157 s = string_catn(s, &size, &ptr, smtp_code, 3);
4158 s = string_catn(s, &size, &ptr, US"-VRFY\r\n", 7);
4162 s = string_catn(s, &size, &ptr, smtp_code, 3);
4163 s = string_catn(s, &size, &ptr, US"-EXPN\r\n", 7);
4166 /* Exim is quite happy with pipelining, so let the other end know that
4167 it is safe to use it, unless advertising is disabled. */
4169 if (pipelining_enable &&
4170 verify_check_host(&pipelining_advertise_hosts) == OK)
4172 s = string_catn(s, &size, &ptr, smtp_code, 3);
4173 s = string_catn(s, &size, &ptr, US"-PIPELINING\r\n", 13);
4174 sync_cmd_limit = NON_SYNC_CMD_PIPELINING;
4175 pipelining_advertised = TRUE;
4179 /* If any server authentication mechanisms are configured, advertise
4180 them if the current host is in auth_advertise_hosts. The problem with
4181 advertising always is that some clients then require users to
4182 authenticate (and aren't configurable otherwise) even though it may not
4183 be necessary (e.g. if the host is in host_accept_relay).
4185 RFC 2222 states that SASL mechanism names contain only upper case
4186 letters, so output the names in upper case, though we actually recognize
4187 them in either case in the AUTH command. */
4191 && !sender_host_authenticated
4193 && verify_check_host(&auth_advertise_hosts) == OK
4198 for (au = auths; au; au = au->next)
4199 if (au->server && (au->advertise_condition == NULL ||
4200 expand_check_condition(au->advertise_condition, au->name,
4201 US"authenticator")))
4206 s = string_catn(s, &size, &ptr, smtp_code, 3);
4207 s = string_catn(s, &size, &ptr, US"-AUTH", 5);
4209 auth_advertised = TRUE;
4212 s = string_catn(s, &size, &ptr, US" ", 1);
4213 s = string_cat (s, &size, &ptr, au->public_name);
4214 while (++saveptr < ptr) s[saveptr] = toupper(s[saveptr]);
4215 au->advertised = TRUE;
4218 au->advertised = FALSE;
4220 if (!first) s = string_catn(s, &size, &ptr, US"\r\n", 2);
4223 /* RFC 3030 CHUNKING */
4225 if (verify_check_host(&chunking_advertise_hosts) != FAIL)
4227 s = string_catn(s, &size, &ptr, smtp_code, 3);
4228 s = string_catn(s, &size, &ptr, US"-CHUNKING\r\n", 11);
4229 chunking_offered = TRUE;
4230 chunking_state = CHUNKING_OFFERED;
4233 /* Advertise TLS (Transport Level Security) aka SSL (Secure Socket Layer)
4234 if it has been included in the binary, and the host matches
4235 tls_advertise_hosts. We must *not* advertise if we are already in a
4236 secure connection. */
4239 if (tls_in.active < 0 &&
4240 verify_check_host(&tls_advertise_hosts) != FAIL)
4242 s = string_catn(s, &size, &ptr, smtp_code, 3);
4243 s = string_catn(s, &size, &ptr, US"-STARTTLS\r\n", 11);
4244 tls_advertised = TRUE;
4248 #ifndef DISABLE_PRDR
4249 /* Per Recipient Data Response, draft by Eric A. Hall extending RFC */
4252 s = string_catn(s, &size, &ptr, smtp_code, 3);
4253 s = string_catn(s, &size, &ptr, US"-PRDR\r\n", 7);
4258 if ( accept_8bitmime
4259 && verify_check_host(&smtputf8_advertise_hosts) != FAIL)
4261 s = string_catn(s, &size, &ptr, smtp_code, 3);
4262 s = string_catn(s, &size, &ptr, US"-SMTPUTF8\r\n", 11);
4263 smtputf8_advertised = TRUE;
4267 /* Finish off the multiline reply with one that is always available. */
4269 s = string_catn(s, &size, &ptr, smtp_code, 3);
4270 s = string_catn(s, &size, &ptr, US" HELP\r\n", 7);
4273 /* Terminate the string (for debug), write it, and note that HELO/EHLO
4279 if (tls_in.active >= 0) (void)tls_write(TRUE, s, ptr); else
4283 int i = fwrite(s, 1, ptr, smtp_out); i = i; /* compiler quietening */
4288 while ((cr = Ustrchr(s, '\r')) != NULL) /* lose CRs */
4289 memmove(cr, cr + 1, (ptr--) - (cr - s));
4290 debug_printf("SMTP>> %s", s);
4294 /* Reset the protocol and the state, abandoning any previous message. */
4296 (sender_host_address ? protocols : protocols_local)
4298 ? pextend + (sender_host_authenticated ? pauthed : 0)
4300 + (tls_in.active >= 0 ? pcrpted : 0)
4302 cancel_cutthrough_connection(TRUE, US"sent EHLO response");
4303 smtp_reset(reset_point);
4305 break; /* HELO/EHLO */
4308 /* The MAIL command requires an address as an operand. All we do
4309 here is to parse it for syntactic correctness. The form "<>" is
4310 a special case which converts into an empty string. The start/end
4311 pointers in the original are not used further for this address, as
4312 it is the canonical extracted address which is all that is kept. */
4316 smtp_mailcmd_count++; /* Count for limit and ratelimit */
4317 was_rej_mail = TRUE; /* Reset if accepted */
4318 env_mail_type_t * mail_args; /* Sanity check & validate args */
4320 if (helo_required && !helo_seen)
4322 smtp_printf("503 HELO or EHLO required\r\n");
4323 log_write(0, LOG_MAIN|LOG_REJECT, "rejected MAIL from %s: no "
4324 "HELO/EHLO given", host_and_ident(FALSE));
4328 if (sender_address != NULL)
4330 done = synprot_error(L_smtp_protocol_error, 503, NULL,
4331 US"sender already given");
4335 if (smtp_cmd_data[0] == 0)
4337 done = synprot_error(L_smtp_protocol_error, 501, NULL,
4338 US"MAIL must have an address operand");
4342 /* Check to see if the limit for messages per connection would be
4343 exceeded by accepting further messages. */
4345 if (smtp_accept_max_per_connection > 0 &&
4346 smtp_mailcmd_count > smtp_accept_max_per_connection)
4348 smtp_printf("421 too many messages in this connection\r\n");
4349 log_write(0, LOG_MAIN|LOG_REJECT, "rejected MAIL command %s: too many "
4350 "messages in one connection", host_and_ident(TRUE));
4354 /* Reset for start of message - even if this is going to fail, we
4355 obviously need to throw away any previous data. */
4357 cancel_cutthrough_connection(TRUE, US"MAIL received");
4358 smtp_reset(reset_point);
4360 sender_data = recipient_data = NULL;
4362 /* Loop, checking for ESMTP additions to the MAIL FROM command. */
4366 uschar *name, *value, *end;
4367 unsigned long int size;
4368 BOOL arg_error = FALSE;
4370 if (!extract_option(&name, &value)) break;
4372 for (mail_args = env_mail_type_list;
4373 mail_args->value != ENV_MAIL_OPT_NULL;
4376 if (strcmpic(name, mail_args->name) == 0)
4378 if (mail_args->need_value && strcmpic(value, US"") == 0)
4381 switch(mail_args->value)
4383 /* Handle SIZE= by reading the value. We don't do the check till later,
4384 in order to be able to log the sender address on failure. */
4385 case ENV_MAIL_OPT_SIZE:
4386 if (((size = Ustrtoul(value, &end, 10)), *end == 0))
4388 if ((size == ULONG_MAX && errno == ERANGE) || size > INT_MAX)
4390 message_size = (int)size;
4396 /* If this session was initiated with EHLO and accept_8bitmime is set,
4397 Exim will have indicated that it supports the BODY=8BITMIME option. In
4398 fact, it does not support this according to the RFCs, in that it does not
4399 take any special action for forwarding messages containing 8-bit
4400 characters. That is why accept_8bitmime is not the default setting, but
4401 some sites want the action that is provided. We recognize both "8BITMIME"
4402 and "7BIT" as body types, but take no action. */
4403 case ENV_MAIL_OPT_BODY:
4404 if (accept_8bitmime) {
4405 if (strcmpic(value, US"8BITMIME") == 0)
4407 else if (strcmpic(value, US"7BIT") == 0)
4412 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4413 US"invalid data for BODY");
4416 DEBUG(D_receive) debug_printf("8BITMIME: %d\n", body_8bitmime);
4422 /* Handle the two DSN options, but only if configured to do so (which
4423 will have caused "DSN" to be given in the EHLO response). The code itself
4424 is included only if configured in at build time. */
4426 case ENV_MAIL_OPT_RET:
4429 /* Check if RET has already been set */
4432 synprot_error(L_smtp_syntax_error, 501, NULL,
4433 US"RET can be specified once only");
4436 dsn_ret = strcmpic(value, US"HDRS") == 0
4438 : strcmpic(value, US"FULL") == 0
4441 DEBUG(D_receive) debug_printf("DSN_RET: %d\n", dsn_ret);
4442 /* Check for invalid invalid value, and exit with error */
4445 synprot_error(L_smtp_syntax_error, 501, NULL,
4446 US"Value for RET is invalid");
4451 case ENV_MAIL_OPT_ENVID:
4454 /* Check if the dsn envid has been already set */
4455 if (dsn_envid != NULL)
4457 synprot_error(L_smtp_syntax_error, 501, NULL,
4458 US"ENVID can be specified once only");
4461 dsn_envid = string_copy(value);
4462 DEBUG(D_receive) debug_printf("DSN_ENVID: %s\n", dsn_envid);
4466 /* Handle the AUTH extension. If the value given is not "<>" and either
4467 the ACL says "yes" or there is no ACL but the sending host is
4468 authenticated, we set it up as the authenticated sender. However, if the
4469 authenticator set a condition to be tested, we ignore AUTH on MAIL unless
4470 the condition is met. The value of AUTH is an xtext, which means that +,
4471 = and cntrl chars are coded in hex; however "<>" is unaffected by this
4473 case ENV_MAIL_OPT_AUTH:
4474 if (Ustrcmp(value, "<>") != 0)
4479 if (auth_xtextdecode(value, &authenticated_sender) < 0)
4481 /* Put back terminator overrides for error message */
4484 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4485 US"invalid data for AUTH");
4488 if (acl_smtp_mailauth == NULL)
4490 ignore_msg = US"client not authenticated";
4491 rc = (sender_host_authenticated != NULL)? OK : FAIL;
4495 ignore_msg = US"rejected by ACL";
4496 rc = acl_check(ACL_WHERE_MAILAUTH, NULL, acl_smtp_mailauth,
4497 &user_msg, &log_msg);
4503 if (authenticated_by == NULL ||
4504 authenticated_by->mail_auth_condition == NULL ||
4505 expand_check_condition(authenticated_by->mail_auth_condition,
4506 authenticated_by->name, US"authenticator"))
4507 break; /* Accept the AUTH */
4509 ignore_msg = US"server_mail_auth_condition failed";
4510 if (authenticated_id != NULL)
4511 ignore_msg = string_sprintf("%s: authenticated ID=\"%s\"",
4512 ignore_msg, authenticated_id);
4517 authenticated_sender = NULL;
4518 log_write(0, LOG_MAIN, "ignoring AUTH=%s from %s (%s)",
4519 value, host_and_ident(TRUE), ignore_msg);
4522 /* Should only get DEFER or ERROR here. Put back terminator
4523 overrides for error message */
4528 (void)smtp_handle_acl_fail(ACL_WHERE_MAILAUTH, rc, user_msg,
4535 #ifndef DISABLE_PRDR
4536 case ENV_MAIL_OPT_PRDR:
4538 prdr_requested = TRUE;
4543 case ENV_MAIL_OPT_UTF8:
4544 if (smtputf8_advertised)
4546 int old_pool = store_pool;
4548 DEBUG(D_receive) debug_printf("smtputf8 requested\n");
4549 message_smtputf8 = allow_utf8_domains = TRUE;
4550 store_pool = POOL_PERM;
4551 received_protocol = string_sprintf("utf8%s", received_protocol);
4552 store_pool = old_pool;
4556 /* No valid option. Stick back the terminator characters and break
4557 the loop. Do the name-terminator second as extract_option sets
4558 value==name when it found no equal-sign.
4559 An error for a malformed address will occur. */
4560 case ENV_MAIL_OPT_NULL:
4568 /* Break out of for loop if switch() had bad argument or
4569 when start of the email address is reached */
4570 if (arg_error) break;
4573 /* If we have passed the threshold for rate limiting, apply the current
4574 delay, and update it for next time, provided this is a limited host. */
4576 if (smtp_mailcmd_count > smtp_rlm_threshold &&
4577 verify_check_host(&smtp_ratelimit_hosts) == OK)
4579 DEBUG(D_receive) debug_printf("rate limit MAIL: delay %.3g sec\n",
4580 smtp_delay_mail/1000.0);
4581 millisleep((int)smtp_delay_mail);
4582 smtp_delay_mail *= smtp_rlm_factor;
4583 if (smtp_delay_mail > (double)smtp_rlm_limit)
4584 smtp_delay_mail = (double)smtp_rlm_limit;
4587 /* Now extract the address, first applying any SMTP-time rewriting. The
4588 TRUE flag allows "<>" as a sender address. */
4590 raw_sender = rewrite_existflags & rewrite_smtp
4591 ? rewrite_one(smtp_cmd_data, rewrite_smtp, NULL, FALSE, US"",
4592 global_rewrite_rules)
4596 parse_extract_address(raw_sender, &errmess, &start, &end, &sender_domain,
4601 done = synprot_error(L_smtp_syntax_error, 501, smtp_cmd_data, errmess);
4605 sender_address = raw_sender;
4607 /* If there is a configured size limit for mail, check that this message
4608 doesn't exceed it. The check is postponed to this point so that the sender
4611 if (thismessage_size_limit > 0 && message_size > thismessage_size_limit)
4613 smtp_printf("552 Message size exceeds maximum permitted\r\n");
4614 log_write(L_size_reject,
4615 LOG_MAIN|LOG_REJECT, "rejected MAIL FROM:<%s> %s: "
4616 "message too big: size%s=%d max=%d",
4618 host_and_ident(TRUE),
4619 (message_size == INT_MAX)? ">" : "",
4621 thismessage_size_limit);
4622 sender_address = NULL;
4626 /* Check there is enough space on the disk unless configured not to.
4627 When smtp_check_spool_space is set, the check is for thismessage_size_limit
4628 plus the current message - i.e. we accept the message only if it won't
4629 reduce the space below the threshold. Add 5000 to the size to allow for
4630 overheads such as the Received: line and storing of recipients, etc.
4631 By putting the check here, even when SIZE is not given, it allow VRFY
4632 and EXPN etc. to be used when space is short. */
4634 if (!receive_check_fs(
4635 (smtp_check_spool_space && message_size >= 0)?
4636 message_size + 5000 : 0))
4638 smtp_printf("452 Space shortage, please try later\r\n");
4639 sender_address = NULL;
4643 /* If sender_address is unqualified, reject it, unless this is a locally
4644 generated message, or the sending host or net is permitted to send
4645 unqualified addresses - typically local machines behaving as MUAs -
4646 in which case just qualify the address. The flag is set above at the start
4647 of the SMTP connection. */
4649 if (sender_domain == 0 && sender_address[0] != 0)
4651 if (allow_unqualified_sender)
4653 sender_domain = Ustrlen(sender_address) + 1;
4654 sender_address = rewrite_address_qualify(sender_address, FALSE);
4655 DEBUG(D_receive) debug_printf("unqualified address %s accepted\n",
4660 smtp_printf("501 %s: sender address must contain a domain\r\n",
4662 log_write(L_smtp_syntax_error,
4663 LOG_MAIN|LOG_REJECT,
4664 "unqualified sender rejected: <%s> %s%s",
4666 host_and_ident(TRUE),
4668 sender_address = NULL;
4673 /* Apply an ACL check if one is defined, before responding. Afterwards,
4674 when pipelining is not advertised, do another sync check in case the ACL
4675 delayed and the client started sending in the meantime. */
4679 rc = acl_check(ACL_WHERE_MAIL, NULL, acl_smtp_mail, &user_msg, &log_msg);
4680 if (rc == OK && !pipelining_advertised && !check_sync())
4686 if (rc == OK || rc == DISCARD)
4689 smtp_printf("%s%s%s", US"250 OK",
4690 #ifndef DISABLE_PRDR
4691 prdr_requested ? US", PRDR Requested" : US"",
4698 #ifndef DISABLE_PRDR
4700 user_msg = string_sprintf("%s%s", user_msg, US", PRDR Requested");
4702 smtp_user_msg(US"250", user_msg);
4704 smtp_delay_rcpt = smtp_rlr_base;
4705 recipients_discarded = (rc == DISCARD);
4706 was_rej_mail = FALSE;
4710 done = smtp_handle_acl_fail(ACL_WHERE_MAIL, rc, user_msg, log_msg);
4711 sender_address = NULL;
4716 /* The RCPT command requires an address as an operand. There may be any
4717 number of RCPT commands, specifying multiple recipients. We build them all
4718 into a data structure. The start/end values given by parse_extract_address
4719 are not used, as we keep only the extracted address. */
4724 was_rcpt = rcpt_in_progress = TRUE;
4726 /* There must be a sender address; if the sender was rejected and
4727 pipelining was advertised, we assume the client was pipelining, and do not
4728 count this as a protocol error. Reset was_rej_mail so that further RCPTs
4729 get the same treatment. */
4731 if (sender_address == NULL)
4733 if (pipelining_advertised && last_was_rej_mail)
4735 smtp_printf("503 sender not yet given\r\n");
4736 was_rej_mail = TRUE;
4740 done = synprot_error(L_smtp_protocol_error, 503, NULL,
4741 US"sender not yet given");
4742 was_rcpt = FALSE; /* Not a valid RCPT */
4748 /* Check for an operand */
4750 if (smtp_cmd_data[0] == 0)
4752 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4753 US"RCPT must have an address operand");
4758 /* Set the DSN flags orcpt and dsn_flags from the session*/
4764 uschar *name, *value;
4766 if (!extract_option(&name, &value))
4769 if (dsn_advertised && strcmpic(name, US"ORCPT") == 0)
4771 /* Check whether orcpt has been already set */
4774 synprot_error(L_smtp_syntax_error, 501, NULL,
4775 US"ORCPT can be specified once only");
4778 orcpt = string_copy(value);
4779 DEBUG(D_receive) debug_printf("DSN orcpt: %s\n", orcpt);
4782 else if (dsn_advertised && strcmpic(name, US"NOTIFY") == 0)
4784 /* Check if the notify flags have been already set */
4787 synprot_error(L_smtp_syntax_error, 501, NULL,
4788 US"NOTIFY can be specified once only");
4791 if (strcmpic(value, US"NEVER") == 0)
4792 flags |= rf_notify_never;
4799 while (*pp != 0 && *pp != ',') pp++;
4800 if (*pp == ',') *pp++ = 0;
4801 if (strcmpic(p, US"SUCCESS") == 0)
4803 DEBUG(D_receive) debug_printf("DSN: Setting notify success\n");
4804 flags |= rf_notify_success;
4806 else if (strcmpic(p, US"FAILURE") == 0)
4808 DEBUG(D_receive) debug_printf("DSN: Setting notify failure\n");
4809 flags |= rf_notify_failure;
4811 else if (strcmpic(p, US"DELAY") == 0)
4813 DEBUG(D_receive) debug_printf("DSN: Setting notify delay\n");
4814 flags |= rf_notify_delay;
4818 /* Catch any strange values */
4819 synprot_error(L_smtp_syntax_error, 501, NULL,
4820 US"Invalid value for NOTIFY parameter");
4825 DEBUG(D_receive) debug_printf("DSN Flags: %x\n", flags);
4829 /* Unknown option. Stick back the terminator characters and break
4830 the loop. An error for a malformed address will occur. */
4834 DEBUG(D_receive) debug_printf("Invalid RCPT option: %s : %s\n", name, value);
4841 /* Apply SMTP rewriting then extract the working address. Don't allow "<>"
4842 as a recipient address */
4844 recipient = rewrite_existflags & rewrite_smtp
4845 ? rewrite_one(smtp_cmd_data, rewrite_smtp, NULL, FALSE, US"",
4846 global_rewrite_rules)
4849 if (!(recipient = parse_extract_address(recipient, &errmess, &start, &end,
4850 &recipient_domain, FALSE)))
4852 done = synprot_error(L_smtp_syntax_error, 501, smtp_cmd_data, errmess);
4857 /* If the recipient address is unqualified, reject it, unless this is a
4858 locally generated message. However, unqualified addresses are permitted
4859 from a configured list of hosts and nets - typically when behaving as
4860 MUAs rather than MTAs. Sad that SMTP is used for both types of traffic,
4861 really. The flag is set at the start of the SMTP connection.
4863 RFC 1123 talks about supporting "the reserved mailbox postmaster"; I always
4864 assumed this meant "reserved local part", but the revision of RFC 821 and
4865 friends now makes it absolutely clear that it means *mailbox*. Consequently
4866 we must always qualify this address, regardless. */
4868 if (!recipient_domain)
4869 if (!(recipient_domain = qualify_recipient(&recipient, smtp_cmd_data,
4876 /* Check maximum allowed */
4878 if (rcpt_count > recipients_max && recipients_max > 0)
4880 if (recipients_max_reject)
4883 smtp_printf("552 too many recipients\r\n");
4885 log_write(0, LOG_MAIN|LOG_REJECT, "too many recipients: message "
4886 "rejected: sender=<%s> %s", sender_address, host_and_ident(TRUE));
4891 smtp_printf("452 too many recipients\r\n");
4893 log_write(0, LOG_MAIN|LOG_REJECT, "too many recipients: excess "
4894 "temporarily rejected: sender=<%s> %s", sender_address,
4895 host_and_ident(TRUE));
4902 /* If we have passed the threshold for rate limiting, apply the current
4903 delay, and update it for next time, provided this is a limited host. */
4905 if (rcpt_count > smtp_rlr_threshold &&
4906 verify_check_host(&smtp_ratelimit_hosts) == OK)
4908 DEBUG(D_receive) debug_printf("rate limit RCPT: delay %.3g sec\n",
4909 smtp_delay_rcpt/1000.0);
4910 millisleep((int)smtp_delay_rcpt);
4911 smtp_delay_rcpt *= smtp_rlr_factor;
4912 if (smtp_delay_rcpt > (double)smtp_rlr_limit)
4913 smtp_delay_rcpt = (double)smtp_rlr_limit;
4916 /* If the MAIL ACL discarded all the recipients, we bypass ACL checking
4917 for them. Otherwise, check the access control list for this recipient. As
4918 there may be a delay in this, re-check for a synchronization error
4919 afterwards, unless pipelining was advertised. */
4921 if (recipients_discarded)
4924 if ( (rc = acl_check(ACL_WHERE_RCPT, recipient, acl_smtp_rcpt, &user_msg,
4926 && !pipelining_advertised && !check_sync())
4929 /* The ACL was happy */
4934 smtp_user_msg(US"250", user_msg);
4936 smtp_printf("250 Accepted\r\n");
4937 receive_add_recipient(recipient, -1);
4939 /* Set the dsn flags in the recipients_list */
4940 recipients_list[recipients_count-1].orcpt = orcpt;
4941 recipients_list[recipients_count-1].dsn_flags = flags;
4943 DEBUG(D_receive) debug_printf("DSN: orcpt: %s flags: %d\n",
4944 recipients_list[recipients_count-1].orcpt,
4945 recipients_list[recipients_count-1].dsn_flags);
4948 /* The recipient was discarded */
4950 else if (rc == DISCARD)
4953 smtp_user_msg(US"250", user_msg);
4955 smtp_printf("250 Accepted\r\n");
4958 log_write(0, LOG_MAIN|LOG_REJECT, "%s F=<%s> RCPT %s: "
4959 "discarded by %s ACL%s%s", host_and_ident(TRUE),
4960 sender_address_unrewritten? sender_address_unrewritten : sender_address,
4961 smtp_cmd_argument, recipients_discarded? "MAIL" : "RCPT",
4962 log_msg ? US": " : US"", log_msg ? log_msg : US"");
4965 /* Either the ACL failed the address, or it was deferred. */
4969 if (rc == FAIL) rcpt_fail_count++; else rcpt_defer_count++;
4970 done = smtp_handle_acl_fail(ACL_WHERE_RCPT, rc, user_msg, log_msg);
4975 /* The DATA command is legal only if it follows successful MAIL FROM
4976 and RCPT TO commands. However, if pipelining is advertised, a bad DATA is
4977 not counted as a protocol error if it follows RCPT (which must have been
4978 rejected if there are no recipients.) This function is complete when a
4979 valid DATA command is encountered.
4981 Note concerning the code used: RFC 2821 says this:
4983 - If there was no MAIL, or no RCPT, command, or all such commands
4984 were rejected, the server MAY return a "command out of sequence"
4985 (503) or "no valid recipients" (554) reply in response to the
4988 The example in the pipelining RFC 2920 uses 554, but I use 503 here
4989 because it is the same whether pipelining is in use or not.
4991 If all the RCPT commands that precede DATA provoked the same error message
4992 (often indicating some kind of system error), it is helpful to include it
4993 with the DATA rejection (an idea suggested by Tony Finch). */
5000 if (chunking_state != CHUNKING_OFFERED)
5002 done = synprot_error(L_smtp_protocol_error, 503, NULL,
5003 US"BDAT command used when CHUNKING not advertised");
5007 /* grab size, endmarker */
5009 if (sscanf(CS smtp_cmd_data, "%u %n", &chunking_datasize, &n) < 1)
5011 done = synprot_error(L_smtp_protocol_error, 501, NULL,
5012 US"missing size for BDAT command");
5015 chunking_state = strcmpic(smtp_cmd_data+n, US"LAST") == 0
5016 ? CHUNKING_LAST : CHUNKING_ACTIVE;
5017 chunking_data_left = chunking_datasize;
5018 DEBUG(D_receive) debug_printf("chunking state %d, %d bytes\n",
5019 (int)chunking_state, chunking_data_left);
5021 lwr_receive_getc = receive_getc;
5022 lwr_receive_getbuf = receive_getbuf;
5023 lwr_receive_ungetc = receive_ungetc;
5024 receive_getc = bdat_getc;
5025 receive_ungetc = bdat_ungetc;
5033 DATA_BDAT: /* Common code for DATA and BDAT */
5034 if (!discarded && recipients_count <= 0)
5036 if (rcpt_smtp_response_same && rcpt_smtp_response != NULL)
5038 uschar *code = US"503";
5039 int len = Ustrlen(rcpt_smtp_response);
5040 smtp_respond(code, 3, FALSE, US"All RCPT commands were rejected with "
5042 /* Responses from smtp_printf() will have \r\n on the end */
5043 if (len > 2 && rcpt_smtp_response[len-2] == '\r')
5044 rcpt_smtp_response[len-2] = 0;
5045 smtp_respond(code, 3, FALSE, rcpt_smtp_response);
5047 if (pipelining_advertised && last_was_rcpt)
5048 smtp_printf("503 Valid RCPT command must precede %s\r\n",
5049 smtp_names[smtp_connection_had[smtp_ch_index-1]]);
5051 done = synprot_error(L_smtp_protocol_error, 503, NULL,
5052 smtp_connection_had[smtp_ch_index-1] == SCH_DATA
5053 ? US"valid RCPT command must precede DATA"
5054 : US"valid RCPT command must precede BDAT");
5056 if (chunking_state > CHUNKING_OFFERED)
5061 if (toomany && recipients_max_reject)
5063 sender_address = NULL; /* This will allow a new MAIL without RSET */
5064 sender_address_unrewritten = NULL;
5065 smtp_printf("554 Too many recipients\r\n");
5069 if (chunking_state > CHUNKING_OFFERED)
5070 rc = OK; /* No predata ACL or go-ahead output for BDAT */
5073 /* If there is an ACL, re-check the synchronization afterwards, since the
5074 ACL may have delayed. To handle cutthrough delivery enforce a dummy call
5075 to get the DATA command sent. */
5077 if (acl_smtp_predata == NULL && cutthrough.fd < 0)
5081 uschar * acl = acl_smtp_predata ? acl_smtp_predata : US"accept";
5082 enable_dollar_recipients = TRUE;
5083 rc = acl_check(ACL_WHERE_PREDATA, NULL, acl, &user_msg,
5085 enable_dollar_recipients = FALSE;
5086 if (rc == OK && !check_sync())
5090 { /* Either the ACL failed the address, or it was deferred. */
5091 done = smtp_handle_acl_fail(ACL_WHERE_PREDATA, rc, user_msg, log_msg);
5097 smtp_user_msg(US"354", user_msg);
5100 "354 Enter message, ending with \".\" on a line by itself\r\n");
5104 if (smtp_in) /* all ACKs needed to ramp window up for bulk data */
5105 (void) setsockopt(fileno(smtp_in), IPPROTO_TCP, TCP_QUICKACK,
5106 US &on, sizeof(on));
5109 message_ended = END_NOTENDED; /* Indicate in middle of data */
5120 if (!(address = parse_extract_address(smtp_cmd_data, &errmess,
5121 &start, &end, &recipient_domain, FALSE)))
5123 smtp_printf("501 %s\r\n", errmess);
5127 if (!recipient_domain)
5128 if (!(recipient_domain = qualify_recipient(&address, smtp_cmd_data,
5132 if ((rc = acl_check(ACL_WHERE_VRFY, address, acl_smtp_vrfy,
5133 &user_msg, &log_msg)) != OK)
5134 done = smtp_handle_acl_fail(ACL_WHERE_VRFY, rc, user_msg, log_msg);
5138 address_item * addr = deliver_make_addr(address, FALSE);
5140 switch(verify_address(addr, NULL, vopt_is_recipient | vopt_qualify, -1,
5141 -1, -1, NULL, NULL, NULL))
5144 s = string_sprintf("250 <%s> is deliverable", address);
5148 s = (addr->user_message != NULL)?
5149 string_sprintf("451 <%s> %s", address, addr->user_message) :
5150 string_sprintf("451 Cannot resolve <%s> at this time", address);
5154 s = (addr->user_message != NULL)?
5155 string_sprintf("550 <%s> %s", address, addr->user_message) :
5156 string_sprintf("550 <%s> is not deliverable", address);
5157 log_write(0, LOG_MAIN, "VRFY failed for %s %s",
5158 smtp_cmd_argument, host_and_ident(TRUE));
5162 smtp_printf("%s\r\n", s);
5170 rc = acl_check(ACL_WHERE_EXPN, NULL, acl_smtp_expn, &user_msg, &log_msg);
5172 done = smtp_handle_acl_fail(ACL_WHERE_EXPN, rc, user_msg, log_msg);
5175 BOOL save_log_testing_mode = log_testing_mode;
5176 address_test_mode = log_testing_mode = TRUE;
5177 (void) verify_address(deliver_make_addr(smtp_cmd_data, FALSE),
5178 smtp_out, vopt_is_recipient | vopt_qualify | vopt_expn, -1, -1, -1,
5180 address_test_mode = FALSE;
5181 log_testing_mode = save_log_testing_mode; /* true for -bh */
5190 if (!tls_advertised)
5192 done = synprot_error(L_smtp_protocol_error, 503, NULL,
5193 US"STARTTLS command used when not advertised");
5197 /* Apply an ACL check if one is defined */
5199 if ( acl_smtp_starttls
5200 && (rc = acl_check(ACL_WHERE_STARTTLS, NULL, acl_smtp_starttls,
5201 &user_msg, &log_msg)) != OK
5204 done = smtp_handle_acl_fail(ACL_WHERE_STARTTLS, rc, user_msg, log_msg);
5208 /* RFC 2487 is not clear on when this command may be sent, though it
5209 does state that all information previously obtained from the client
5210 must be discarded if a TLS session is started. It seems reasonable to
5211 do an implied RSET when STARTTLS is received. */
5213 incomplete_transaction_log(US"STARTTLS");
5214 cancel_cutthrough_connection(TRUE, US"STARTTLS received");
5215 smtp_reset(reset_point);
5217 cmd_list[CMD_LIST_STARTTLS].is_mail_cmd = FALSE;
5219 /* There's an attack where more data is read in past the STARTTLS command
5220 before TLS is negotiated, then assumed to be part of the secure session
5221 when used afterwards; we use segregated input buffers, so are not
5222 vulnerable, but we want to note when it happens and, for sheer paranoia,
5223 ensure that the buffer is "wiped".
5224 Pipelining sync checks will normally have protected us too, unless disabled
5225 by configuration. */
5227 if (receive_smtp_buffered())
5230 debug_printf("Non-empty input buffer after STARTTLS; naive attack?\n");
5231 if (tls_in.active < 0)
5232 smtp_inend = smtp_inptr = smtp_inbuffer;
5233 /* and if TLS is already active, tls_server_start() should fail */
5236 /* There is nothing we value in the input buffer and if TLS is successfully
5237 negotiated, we won't use this buffer again; if TLS fails, we'll just read
5238 fresh content into it. The buffer contains arbitrary content from an
5239 untrusted remote source; eg: NOOP <shellcode>\r\nSTARTTLS\r\n
5240 It seems safest to just wipe away the content rather than leave it as a
5241 target to jump to. */
5243 memset(smtp_inbuffer, 0, IN_BUFFER_SIZE);
5245 /* Attempt to start up a TLS session, and if successful, discard all
5246 knowledge that was obtained previously. At least, that's what the RFC says,
5247 and that's what happens by default. However, in order to work round YAEB,
5248 there is an option to remember the esmtp state. Sigh.
5250 We must allow for an extra EHLO command and an extra AUTH command after
5251 STARTTLS that don't add to the nonmail command count. */
5254 if ((rc = tls_server_start(tls_require_ciphers, &s)) == OK)
5256 if (!tls_remember_esmtp)
5257 helo_seen = esmtp = auth_advertised = pipelining_advertised = FALSE;
5258 cmd_list[CMD_LIST_EHLO].is_mail_cmd = TRUE;
5259 cmd_list[CMD_LIST_AUTH].is_mail_cmd = TRUE;
5260 cmd_list[CMD_LIST_TLS_AUTH].is_mail_cmd = TRUE;
5261 if (sender_helo_name != NULL)
5263 store_free(sender_helo_name);
5264 sender_helo_name = NULL;
5265 host_build_sender_fullhost(); /* Rebuild */
5266 set_process_info("handling incoming TLS connection from %s",
5267 host_and_ident(FALSE));
5270 (sender_host_address ? protocols : protocols_local)
5272 ? pextend + (sender_host_authenticated ? pauthed : 0)
5274 + (tls_in.active >= 0 ? pcrpted : 0)
5277 sender_host_authenticated = NULL;
5278 authenticated_id = NULL;
5279 sync_cmd_limit = NON_SYNC_CMD_NON_PIPELINING;
5280 DEBUG(D_tls) debug_printf("TLS active\n");
5281 break; /* Successful STARTTLS */
5284 (void) smtp_log_tls_fail(s);
5286 /* Some local configuration problem was discovered before actually trying
5287 to do a TLS handshake; give a temporary error. */
5291 smtp_printf("454 TLS currently unavailable\r\n");
5295 /* Hard failure. Reject everything except QUIT or closed connection. One
5296 cause for failure is a nested STARTTLS, in which case tls_in.active remains
5297 set, but we must still reject all incoming commands. */
5299 DEBUG(D_tls) debug_printf("TLS failed to start\n");
5300 while (done <= 0) switch(smtp_read_command(FALSE, GETC_BUFFER_UNLIMITED))
5303 log_write(L_smtp_connection, LOG_MAIN, "%s closed by EOF",
5304 smtp_get_connection_info());
5305 smtp_notquit_exit(US"tls-failed", NULL, NULL);
5309 /* It is perhaps arguable as to which exit ACL should be called here,
5310 but as it is probably a situation that almost never arises, it
5311 probably doesn't matter. We choose to call the real QUIT ACL, which in
5312 some sense is perhaps "right". */
5317 && ((rc = acl_check(ACL_WHERE_QUIT, NULL, acl_smtp_quit, &user_msg,
5318 &log_msg)) == ERROR))
5319 log_write(0, LOG_MAIN|LOG_PANIC, "ACL for QUIT returned ERROR: %s",
5322 smtp_respond(US"221", 3, TRUE, user_msg);
5324 smtp_printf("221 %s closing connection\r\n", smtp_active_hostname);
5325 log_write(L_smtp_connection, LOG_MAIN, "%s closed by QUIT",
5326 smtp_get_connection_info());
5331 smtp_printf("554 Security failure\r\n");
5334 tls_close(TRUE, TRUE);
5339 /* The ACL for QUIT is provided for gathering statistical information or
5340 similar; it does not affect the response code, but it can supply a custom
5344 smtp_quit_handler(&user_msg, &log_msg);
5350 smtp_rset_handler();
5351 cancel_cutthrough_connection(TRUE, US"RSET received");
5352 smtp_reset(reset_point);
5359 smtp_printf("250 OK\r\n");
5363 /* Show ETRN/EXPN/VRFY if there's an ACL for checking hosts; if actually
5364 used, a check will be done for permitted hosts. Show STARTTLS only if not
5365 already in a TLS session and if it would be advertised in the EHLO
5370 smtp_printf("214-Commands supported:\r\n");
5374 Ustrcat(buffer, " AUTH");
5376 if (tls_in.active < 0 &&
5377 verify_check_host(&tls_advertise_hosts) != FAIL)
5378 Ustrcat(buffer, " STARTTLS");
5380 Ustrcat(buffer, " HELO EHLO MAIL RCPT DATA BDAT");
5381 Ustrcat(buffer, " NOOP QUIT RSET HELP");
5382 if (acl_smtp_etrn != NULL) Ustrcat(buffer, " ETRN");
5383 if (acl_smtp_expn != NULL) Ustrcat(buffer, " EXPN");
5384 if (acl_smtp_vrfy != NULL) Ustrcat(buffer, " VRFY");
5385 smtp_printf("214%s\r\n", buffer);
5391 incomplete_transaction_log(US"connection lost");
5392 smtp_notquit_exit(US"connection-lost", US"421",
5393 US"%s lost input connection", smtp_active_hostname);
5395 /* Don't log by default unless in the middle of a message, as some mailers
5396 just drop the call rather than sending QUIT, and it clutters up the logs.
5399 if (sender_address != NULL || recipients_count > 0)
5400 log_write(L_lost_incoming_connection,
5402 "unexpected %s while reading SMTP command from %s%s",
5403 sender_host_unknown? "EOF" : "disconnection",
5404 host_and_ident(FALSE), smtp_read_error);
5406 else log_write(L_smtp_connection, LOG_MAIN, "%s lost%s",
5407 smtp_get_connection_info(), smtp_read_error);
5415 if (sender_address != NULL)
5417 done = synprot_error(L_smtp_protocol_error, 503, NULL,
5418 US"ETRN is not permitted inside a transaction");
5422 log_write(L_etrn, LOG_MAIN, "ETRN %s received from %s", smtp_cmd_argument,
5423 host_and_ident(FALSE));
5425 if ((rc = acl_check(ACL_WHERE_ETRN, NULL, acl_smtp_etrn,
5426 &user_msg, &log_msg)) != OK)
5428 done = smtp_handle_acl_fail(ACL_WHERE_ETRN, rc, user_msg, log_msg);
5432 /* Compute the serialization key for this command. */
5434 etrn_serialize_key = string_sprintf("etrn-%s\n", smtp_cmd_data);
5436 /* If a command has been specified for running as a result of ETRN, we
5437 permit any argument to ETRN. If not, only the # standard form is permitted,
5438 since that is strictly the only kind of ETRN that can be implemented
5439 according to the RFC. */
5441 if (smtp_etrn_command != NULL)
5445 etrn_command = smtp_etrn_command;
5446 deliver_domain = smtp_cmd_data;
5447 rc = transport_set_up_command(&argv, smtp_etrn_command, TRUE, 0, NULL,
5448 US"ETRN processing", &error);
5449 deliver_domain = NULL;
5452 log_write(0, LOG_MAIN|LOG_PANIC, "failed to set up ETRN command: %s",
5454 smtp_printf("458 Internal failure\r\n");
5459 /* Else set up to call Exim with the -R option. */
5463 if (*smtp_cmd_data++ != '#')
5465 done = synprot_error(L_smtp_syntax_error, 501, NULL,
5466 US"argument must begin with #");
5469 etrn_command = US"exim -R";
5470 argv = CUSS child_exec_exim(CEE_RETURN_ARGV, TRUE, NULL, TRUE,
5471 *queue_name ? 4 : 2,
5472 US"-R", smtp_cmd_data,
5473 US"-MCG", queue_name);
5476 /* If we are host-testing, don't actually do anything. */
5482 debug_printf("ETRN command is: %s\n", etrn_command);
5483 debug_printf("ETRN command execution skipped\n");
5485 if (user_msg == NULL) smtp_printf("250 OK\r\n");
5486 else smtp_user_msg(US"250", user_msg);
5491 /* If ETRN queue runs are to be serialized, check the database to
5492 ensure one isn't already running. */
5494 if (smtp_etrn_serialize && !enq_start(etrn_serialize_key, 1))
5496 smtp_printf("458 Already processing %s\r\n", smtp_cmd_data);
5500 /* Fork a child process and run the command. We don't want to have to
5501 wait for the process at any point, so set SIGCHLD to SIG_IGN before
5502 forking. It should be set that way anyway for external incoming SMTP,
5503 but we save and restore to be tidy. If serialization is required, we
5504 actually run the command in yet another process, so we can wait for it
5505 to complete and then remove the serialization lock. */
5507 oldsignal = signal(SIGCHLD, SIG_IGN);
5509 if ((pid = fork()) == 0)
5511 smtp_input = FALSE; /* This process is not associated with the */
5512 (void)fclose(smtp_in); /* SMTP call any more. */
5513 (void)fclose(smtp_out);
5515 signal(SIGCHLD, SIG_DFL); /* Want to catch child */
5517 /* If not serializing, do the exec right away. Otherwise, fork down
5518 into another process. */
5520 if (!smtp_etrn_serialize || (pid = fork()) == 0)
5522 DEBUG(D_exec) debug_print_argv(argv);
5523 exim_nullstd(); /* Ensure std{in,out,err} exist */
5524 execv(CS argv[0], (char *const *)argv);
5525 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "exec of \"%s\" (ETRN) failed: %s",
5526 etrn_command, strerror(errno));
5527 _exit(EXIT_FAILURE); /* paranoia */
5530 /* Obey this if smtp_serialize and the 2nd fork yielded non-zero. That
5531 is, we are in the first subprocess, after forking again. All we can do
5532 for a failing fork is to log it. Otherwise, wait for the 2nd process to
5533 complete, before removing the serialization. */
5536 log_write(0, LOG_MAIN|LOG_PANIC, "2nd fork for serialized ETRN "
5537 "failed: %s", strerror(errno));
5541 DEBUG(D_any) debug_printf("waiting for serialized ETRN process %d\n",
5543 (void)wait(&status);
5544 DEBUG(D_any) debug_printf("serialized ETRN process %d ended\n",
5548 enq_end(etrn_serialize_key);
5549 _exit(EXIT_SUCCESS);
5552 /* Back in the top level SMTP process. Check that we started a subprocess
5553 and restore the signal state. */
5557 log_write(0, LOG_MAIN|LOG_PANIC, "fork of process for ETRN failed: %s",
5559 smtp_printf("458 Unable to fork process\r\n");
5560 if (smtp_etrn_serialize) enq_end(etrn_serialize_key);
5564 if (user_msg == NULL) smtp_printf("250 OK\r\n");
5565 else smtp_user_msg(US"250", user_msg);
5568 signal(SIGCHLD, oldsignal);
5573 done = synprot_error(L_smtp_syntax_error, 501, NULL,
5574 US"unexpected argument data");
5578 /* This currently happens only for NULLs, but could be extended. */
5581 done = synprot_error(L_smtp_syntax_error, 0, NULL, /* Just logs */
5582 US"NULL character(s) present (shown as '?')");
5583 smtp_printf("501 NULL characters are not allowed in SMTP commands\r\n");
5589 if (smtp_inend >= smtp_inbuffer + IN_BUFFER_SIZE)
5590 smtp_inend = smtp_inbuffer + IN_BUFFER_SIZE - 1;
5591 c = smtp_inend - smtp_inptr;
5592 if (c > 150) c = 150;
5594 incomplete_transaction_log(US"sync failure");
5595 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP protocol synchronization error "
5596 "(next input sent too soon: pipelining was%s advertised): "
5597 "rejected \"%s\" %s next input=\"%s\"",
5598 pipelining_advertised? "" : " not",
5599 smtp_cmd_buffer, host_and_ident(TRUE),
5600 string_printing(smtp_inptr));
5601 smtp_notquit_exit(US"synchronization-error", US"554",
5602 US"SMTP synchronization error");
5603 done = 1; /* Pretend eof - drops connection */
5607 case TOO_MANY_NONMAIL_CMD:
5608 s = smtp_cmd_buffer;
5609 while (*s != 0 && !isspace(*s)) s++;
5610 incomplete_transaction_log(US"too many non-mail commands");
5611 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
5612 "nonmail commands (last was \"%.*s\")", host_and_ident(FALSE),
5613 (int)(s - smtp_cmd_buffer), smtp_cmd_buffer);
5614 smtp_notquit_exit(US"bad-commands", US"554", US"Too many nonmail commands");
5615 done = 1; /* Pretend eof - drops connection */
5618 #ifdef SUPPORT_PROXY
5619 case PROXY_FAIL_IGNORE_CMD:
5620 smtp_printf("503 Command refused, required Proxy negotiation failed\r\n");
5625 if (unknown_command_count++ >= smtp_max_unknown_commands)
5627 log_write(L_smtp_syntax_error, LOG_MAIN,
5628 "SMTP syntax error in \"%s\" %s %s",
5629 string_printing(smtp_cmd_buffer), host_and_ident(TRUE),
5630 US"unrecognized command");
5631 incomplete_transaction_log(US"unrecognized command");
5632 smtp_notquit_exit(US"bad-commands", US"500",
5633 US"Too many unrecognized commands");
5635 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
5636 "unrecognized commands (last was \"%s\")", host_and_ident(FALSE),
5637 string_printing(smtp_cmd_buffer));
5640 done = synprot_error(L_smtp_syntax_error, 500, NULL,
5641 US"unrecognized command");
5645 /* This label is used by goto's inside loops that want to break out to
5646 the end of the command-processing loop. */
5649 last_was_rej_mail = was_rej_mail; /* Remember some last commands for */
5650 last_was_rcpt = was_rcpt; /* protocol error handling */
5654 return done - 2; /* Convert yield values */
5659 /* End of smtp_in.c */