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 if (smtp_inptr < smtp_inend)
349 fd = fileno(smtp_in);
354 rc = select(fd + 1, (SELECT_ARG2_TYPE *)&fds, NULL, NULL, &tzero);
356 if (rc <= 0) return TRUE; /* Not ready to read */
357 rc = smtp_getc(GETC_BUFFER_UNLIMITED);
358 if (rc < 0) return TRUE; /* End of file or error */
361 rc = smtp_inend - smtp_inptr;
362 if (rc > 150) rc = 150;
369 /*************************************************
370 * Log incomplete transactions *
371 *************************************************/
373 /* This function is called after a transaction has been aborted by RSET, QUIT,
374 connection drops or other errors. It logs the envelope information received
375 so far in order to preserve address verification attempts.
377 Argument: string to indicate what aborted the transaction
382 incomplete_transaction_log(uschar *what)
384 if (sender_address == NULL || /* No transaction in progress */
385 !LOGGING(smtp_incomplete_transaction))
388 /* Build list of recipients for logging */
390 if (recipients_count > 0)
393 raw_recipients = store_get(recipients_count * sizeof(uschar *));
394 for (i = 0; i < recipients_count; i++)
395 raw_recipients[i] = recipients_list[i].address;
396 raw_recipients_count = recipients_count;
399 log_write(L_smtp_incomplete_transaction, LOG_MAIN|LOG_SENDER|LOG_RECIPIENTS,
400 "%s incomplete transaction (%s)", host_and_ident(TRUE), what);
406 /* Refill the buffer, and notify DKIM verification code.
407 Return false for error or EOF.
411 smtp_refill(unsigned lim)
414 if (!smtp_out) return FALSE;
416 if (smtp_receive_timeout > 0) alarm(smtp_receive_timeout);
418 /* Limit amount read, so non-message data is not fed to DKIM */
420 rc = read(fileno(smtp_in), smtp_inbuffer, MIN(IN_BUFFER_SIZE, lim));
425 /* Must put the error text in fixed store, because this might be during
426 header reading, where it releases unused store above the header. */
429 smtp_had_error = save_errno;
430 smtp_read_error = string_copy_malloc(
431 string_sprintf(" (error: %s)", strerror(save_errno)));
433 else smtp_had_eof = 1;
437 dkim_exim_verify_feed(smtp_inbuffer, rc);
439 smtp_inend = smtp_inbuffer + rc;
440 smtp_inptr = smtp_inbuffer;
444 /*************************************************
445 * SMTP version of getc() *
446 *************************************************/
448 /* This gets the next byte from the SMTP input buffer. If the buffer is empty,
449 it flushes the output, and refills the buffer, with a timeout. The signal
450 handler is set appropriately by the calling function. This function is not used
451 after a connection has negotiated itself into an TLS/SSL state.
453 Arguments: lim Maximum amount to read/buffer
454 Returns: the next character or EOF
458 smtp_getc(unsigned lim)
460 if (smtp_inptr >= smtp_inend)
461 if (!smtp_refill(lim))
463 return *smtp_inptr++;
467 smtp_getbuf(unsigned * len)
472 if (smtp_inptr >= smtp_inend)
473 if (!smtp_refill(*len))
474 { *len = 0; return NULL; }
476 if ((size = smtp_inend - smtp_inptr) > *len) size = *len;
487 int n = smtp_inend - smtp_inptr;
489 dkim_exim_verify_feed(smtp_inptr, n);
494 /* Get a byte from the smtp input, in CHUNKING mode. Handle ack of the
495 previous BDAT chunk and getting new ones when we run out. Uses the
496 underlying smtp_getc or tls_getc both for that and for getting the
497 (buffered) data byte. EOD signals (an expected) no further data.
498 ERR signals a protocol error, and EOF a closed input stream.
500 Called from read_bdat_smtp() in receive.c for the message body, but also
501 by the headers read loop in receive_msg(); manipulates chunking_state
502 to handle the BDAT command/response.
503 Placed here due to the correlation with the above smtp_getc(), which it wraps,
504 and also by the need to do smtp command/response handling.
506 Arguments: lim (ignored)
507 Returns: the next character or ERR, EOD or EOF
511 bdat_getc(unsigned lim)
513 uschar * user_msg = NULL;
522 if (chunking_data_left > 0)
523 return lwr_receive_getc(chunking_data_left--);
525 receive_getc = lwr_receive_getc;
526 receive_getbuf = lwr_receive_getbuf;
527 receive_ungetc = lwr_receive_ungetc;
529 dkim_save = dkim_collect_input;
530 dkim_collect_input = FALSE;
533 /* Unless PIPELINING was offered, there should be no next command
534 until after we ack that chunk */
536 if (!pipelining_advertised && !check_sync())
538 unsigned n = smtp_inend - smtp_inptr;
541 incomplete_transaction_log(US"sync failure");
542 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP protocol synchronization error "
543 "(next input sent too soon: pipelining was not advertised): "
544 "rejected \"%s\" %s next input=\"%s\"",
545 smtp_cmd_buffer, host_and_ident(TRUE),
546 string_printing(string_copyn(smtp_inptr, n)));
547 (void) synprot_error(L_smtp_protocol_error, 554, NULL,
548 US"SMTP synchronization error");
549 goto repeat_until_rset;
552 /* If not the last, ack the received chunk. The last response is delayed
553 until after the data ACL decides on it */
555 if (chunking_state == CHUNKING_LAST)
558 dkim_exim_verify_feed(NULL, 0); /* notify EOD */
563 smtp_printf("250 %u byte chunk received\r\n", chunking_datasize);
564 chunking_state = CHUNKING_OFFERED;
565 DEBUG(D_receive) debug_printf("chunking state %d\n", (int)chunking_state);
567 /* Expect another BDAT cmd from input. RFC 3030 says nothing about
568 QUIT, RSET or NOOP but handling them seems obvious */
571 switch(smtp_read_command(TRUE, 1))
574 (void) synprot_error(L_smtp_protocol_error, 503, NULL,
575 US"only BDAT permissible after non-LAST BDAT");
578 switch(smtp_read_command(TRUE, 1))
580 case QUIT_CMD: smtp_quit_handler(&user_msg, &log_msg); /*FALLTHROUGH */
581 case EOF_CMD: return EOF;
582 case RSET_CMD: smtp_rset_handler(); return ERR;
583 default: if (synprot_error(L_smtp_protocol_error, 503, NULL,
584 US"only RSET accepted now") > 0)
586 goto repeat_until_rset;
590 smtp_quit_handler(&user_msg, &log_msg);
601 smtp_printf("250 OK\r\n");
608 if (sscanf(CS smtp_cmd_data, "%u %n", &chunking_datasize, &n) < 1)
610 (void) synprot_error(L_smtp_protocol_error, 501, NULL,
611 US"missing size for BDAT command");
614 chunking_state = strcmpic(smtp_cmd_data+n, US"LAST") == 0
615 ? CHUNKING_LAST : CHUNKING_ACTIVE;
616 chunking_data_left = chunking_datasize;
617 DEBUG(D_receive) debug_printf("chunking state %d, %d bytes\n",
618 (int)chunking_state, chunking_data_left);
620 if (chunking_datasize == 0)
621 if (chunking_state == CHUNKING_LAST)
625 (void) synprot_error(L_smtp_protocol_error, 504, NULL,
626 US"zero size for BDAT command");
627 goto repeat_until_rset;
630 receive_getc = bdat_getc;
631 receive_getbuf = bdat_getbuf;
632 receive_ungetc = bdat_ungetc;
634 dkim_collect_input = dkim_save;
636 break; /* to top of main loop */
643 bdat_getbuf(unsigned * len)
647 if (chunking_data_left <= 0)
648 { *len = 0; return NULL; }
650 if (*len > chunking_data_left) *len = chunking_data_left;
651 buf = lwr_receive_getbuf(len); /* Either smtp_getbuf or tls_getbuf */
652 chunking_data_left -= *len;
657 bdat_flush_data(void)
659 unsigned n = chunking_data_left;
660 (void) bdat_getbuf(&n);
662 receive_getc = lwr_receive_getc;
663 receive_getbuf = lwr_receive_getbuf;
664 receive_ungetc = lwr_receive_ungetc;
666 if (chunking_state != CHUNKING_LAST)
668 chunking_state = CHUNKING_OFFERED;
669 DEBUG(D_receive) debug_printf("chunking state %d\n", (int)chunking_state);
676 /*************************************************
677 * SMTP version of ungetc() *
678 *************************************************/
680 /* Puts a character back in the input buffer. Only ever
686 Returns: the character
700 chunking_data_left++;
701 return lwr_receive_ungetc(ch);
706 /*************************************************
707 * SMTP version of feof() *
708 *************************************************/
710 /* Tests for a previous EOF
713 Returns: non-zero if the eof flag is set
725 /*************************************************
726 * SMTP version of ferror() *
727 *************************************************/
729 /* Tests for a previous read error, and returns with errno
730 restored to what it was when the error was detected.
733 Returns: non-zero if the error flag is set
739 errno = smtp_had_error;
740 return smtp_had_error;
745 /*************************************************
746 * Test for characters in the SMTP buffer *
747 *************************************************/
749 /* Used at the end of a message
758 return smtp_inptr < smtp_inend;
763 /*************************************************
764 * Write formatted string to SMTP channel *
765 *************************************************/
767 /* This is a separate function so that we don't have to repeat everything for
768 TLS support or debugging. It is global so that the daemon and the
769 authentication functions can use it. It does not return any error indication,
770 because major problems such as dropped connections won't show up till an output
771 flush for non-TLS connections. The smtp_fflush() function is available for
772 checking that: for convenience, TLS output errors are remembered here so that
773 they are also picked up later by smtp_fflush().
777 ... optional arguments
783 smtp_printf(const char *format, ...)
787 va_start(ap, format);
788 smtp_vprintf(format, ap);
792 /* This is split off so that verify.c:respond_printf() can, in effect, call
793 smtp_printf(), bearing in mind that in C a vararg function can't directly
794 call another vararg function, only a function which accepts a va_list. */
797 smtp_vprintf(const char *format, va_list ap)
801 yield = string_vformat(big_buffer, big_buffer_size, format, ap);
805 void *reset_point = store_get(0);
806 uschar *msg_copy, *cr, *end;
807 msg_copy = string_copy(big_buffer);
808 end = msg_copy + Ustrlen(msg_copy);
809 while ((cr = Ustrchr(msg_copy, '\r')) != NULL) /* lose CRs */
810 memmove(cr, cr + 1, (end--) - cr);
811 debug_printf("SMTP>> %s", msg_copy);
812 store_reset(reset_point);
817 log_write(0, LOG_MAIN|LOG_PANIC, "string too large in smtp_printf()");
818 smtp_closedown(US"Unexpected error");
819 exim_exit(EXIT_FAILURE);
822 /* If this is the first output for a (non-batch) RCPT command, see if all RCPTs
823 have had the same. Note: this code is also present in smtp_respond(). It would
824 be tidier to have it only in one place, but when it was added, it was easier to
825 do it that way, so as not to have to mess with the code for the RCPT command,
826 which sometimes uses smtp_printf() and sometimes smtp_respond(). */
828 if (rcpt_in_progress)
830 if (rcpt_smtp_response == NULL)
831 rcpt_smtp_response = string_copy(big_buffer);
832 else if (rcpt_smtp_response_same &&
833 Ustrcmp(rcpt_smtp_response, big_buffer) != 0)
834 rcpt_smtp_response_same = FALSE;
835 rcpt_in_progress = FALSE;
838 /* Now write the string */
841 if (tls_in.active >= 0)
843 if (tls_write(TRUE, big_buffer, Ustrlen(big_buffer)) < 0)
844 smtp_write_error = -1;
849 if (fprintf(smtp_out, "%s", big_buffer) < 0) smtp_write_error = -1;
854 /*************************************************
855 * Flush SMTP out and check for error *
856 *************************************************/
858 /* This function isn't currently used within Exim (it detects errors when it
859 tries to read the next SMTP input), but is available for use in local_scan().
860 For non-TLS connections, it flushes the output and checks for errors. For
861 TLS-connections, it checks for a previously-detected TLS write error.
864 Returns: 0 for no error; -1 after an error
870 if (tls_in.active < 0 && fflush(smtp_out) != 0) smtp_write_error = -1;
871 return smtp_write_error;
876 /*************************************************
877 * SMTP command read timeout *
878 *************************************************/
880 /* Signal handler for timing out incoming SMTP commands. This attempts to
883 Argument: signal number (SIGALRM)
888 command_timeout_handler(int sig)
890 sig = sig; /* Keep picky compilers happy */
891 log_write(L_lost_incoming_connection,
892 LOG_MAIN, "SMTP command timeout on%s connection from %s",
893 (tls_in.active >= 0)? " TLS" : "",
894 host_and_ident(FALSE));
895 if (smtp_batched_input)
896 moan_smtp_batch(NULL, "421 SMTP command timeout"); /* Does not return */
897 smtp_notquit_exit(US"command-timeout", US"421",
898 US"%s: SMTP command timeout - closing connection", smtp_active_hostname);
899 exim_exit(EXIT_FAILURE);
904 /*************************************************
906 *************************************************/
908 /* Signal handler for handling SIGTERM. Again, try to finish tidily.
910 Argument: signal number (SIGTERM)
915 command_sigterm_handler(int sig)
917 sig = sig; /* Keep picky compilers happy */
918 log_write(0, LOG_MAIN, "%s closed after SIGTERM", smtp_get_connection_info());
919 if (smtp_batched_input)
920 moan_smtp_batch(NULL, "421 SIGTERM received"); /* Does not return */
921 smtp_notquit_exit(US"signal-exit", US"421",
922 US"%s: Service not available - closing connection", smtp_active_hostname);
923 exim_exit(EXIT_FAILURE);
930 /*************************************************
931 * Restore socket timeout to previous value *
932 *************************************************/
933 /* If the previous value was successfully retrieved, restore
934 it before returning control to the non-proxy routines
936 Arguments: fd - File descriptor for input
937 get_ok - Successfully retrieved previous values
938 tvtmp - Time struct with previous values
939 vslen - Length of time struct
943 restore_socket_timeout(int fd, int get_ok, struct timeval * tvtmp, socklen_t vslen)
946 (void) setsockopt(fd, SOL_SOCKET, SO_RCVTIMEO, CS tvtmp, vslen);
949 /*************************************************
950 * Check if host is required proxy host *
951 *************************************************/
952 /* The function determines if inbound host will be a regular smtp host
953 or if it is configured that it must use Proxy Protocol. A local
961 check_proxy_protocol_host()
965 if ( sender_host_address
966 && (rc = verify_check_this_host(CUSS &hosts_proxy, NULL, NULL,
967 sender_host_address, NULL)) == OK)
970 debug_printf("Detected proxy protocol configured host\n");
971 proxy_session = TRUE;
973 return proxy_session;
977 /*************************************************
978 * Read data until newline or end of buffer *
979 *************************************************/
980 /* While SMTP is server-speaks-first, TLS is client-speaks-first, so we can't
981 read an entire buffer and assume there will be nothing past a proxy protocol
982 header. Our approach normally is to use stdio, but again that relies upon
983 "STARTTLS\r\n" and a server response before the client starts TLS handshake, or
984 reading _nothing_ before client TLS handshake. So we don't want to use the
985 usual buffering reads which may read enough to block TLS starting.
987 So unfortunately we're down to "read one byte at a time, with a syscall each,
988 and expect a little overhead", for all proxy-opened connections which are v1,
989 just to handle the TLS-on-connect case. Since SSL functions wrap the
990 underlying fd, we can't assume that we can feed them any already-read content.
992 We need to know where to read to, the max capacity, and we'll read until we
993 get a CR and one more character. Let the caller scream if it's CR+!LF.
995 Return the amount read.
999 swallow_until_crlf(int fd, uschar *base, int already, int capacity)
1001 uschar *to = base + already;
1007 /* For "PROXY UNKNOWN\r\n" we, at time of writing, expect to have read
1008 up through the \r; for the _normal_ case, we haven't yet seen the \r. */
1010 cr = memchr(base, '\r', already);
1013 if ((cr - base) < already - 1)
1015 /* \r and presumed \n already within what we have; probably not
1016 actually proxy protocol, but abort cleanly. */
1019 /* \r is last character read, just need one more. */
1023 while (capacity > 0)
1025 do { ret = recv(fd, to, 1, 0); } while (ret == -1 && errno == EINTR);
1037 /* reached end without having room for a final newline, abort */
1042 /*************************************************
1043 * Setup host for proxy protocol *
1044 *************************************************/
1045 /* The function configures the connection based on a header from the
1046 inbound host to use Proxy Protocol. The specification is very exact
1047 so exit with an error if do not find the exact required pieces. This
1048 includes an incorrect number of spaces separating args.
1051 Returns: Boolean success
1055 setup_proxy_protocol_host()
1067 struct { /* TCP/UDP over IPv4, len = 12 */
1073 struct { /* TCP/UDP over IPv6, len = 36 */
1074 uint8_t src_addr[16];
1075 uint8_t dst_addr[16];
1079 struct { /* AF_UNIX sockets, len = 216 */
1080 uschar src_addr[108];
1081 uschar dst_addr[108];
1087 /* Temp variables used in PPv2 address:port parsing */
1089 char tmpip[INET_ADDRSTRLEN];
1090 struct sockaddr_in tmpaddr;
1091 char tmpip6[INET6_ADDRSTRLEN];
1092 struct sockaddr_in6 tmpaddr6;
1094 /* We can't read "all data until end" because while SMTP is
1095 server-speaks-first, the TLS handshake is client-speaks-first, so for
1096 TLS-on-connect ports the proxy protocol header will usually be immediately
1097 followed by a TLS handshake, and with N TLS libraries, we can't reliably
1098 reinject data for reading by those. So instead we first read "enough to be
1099 safely read within the header, and figure out how much more to read".
1100 For v1 we will later read to the end-of-line, for v2 we will read based upon
1103 The v2 sig is 12 octets, and another 4 gets us the length, so we know how much
1104 data is needed total. For v1, where the line looks like:
1105 PROXY TCPn L3src L3dest SrcPort DestPort \r\n
1107 However, for v1 there's also `PROXY UNKNOWN\r\n` which is only 15 octets.
1108 We seem to support that. So, if we read 14 octets then we can tell if we're
1109 v2 or v1. If we're v1, we can continue reading as normal.
1111 If we're v2, we can't slurp up the entire header. We need the length in the
1112 15th & 16th octets, then to read everything after that.
1114 So to safely handle v1 and v2, with client-sent-first supported correctly,
1115 we have to do a minimum of 3 read calls, not 1. Eww.
1118 #define PROXY_INITIAL_READ 14
1119 #define PROXY_V2_HEADER_SIZE 16
1120 #if PROXY_INITIAL_READ > PROXY_V2_HEADER_SIZE
1121 # error Code bug in sizes of data to read for proxy usage
1126 int fd = fileno(smtp_in);
1127 const char v2sig[12] = "\x0D\x0A\x0D\x0A\x00\x0D\x0A\x51\x55\x49\x54\x0A";
1128 uschar * iptype; /* To display debug info */
1130 struct timeval tvtmp;
1131 socklen_t vslen = sizeof(struct timeval);
1134 /* Save current socket timeout values */
1135 get_ok = getsockopt(fd, SOL_SOCKET, SO_RCVTIMEO, CS &tvtmp, &vslen);
1137 /* Proxy Protocol host must send header within a short time
1138 (default 3 seconds) or it's considered invalid */
1139 tv.tv_sec = PROXY_NEGOTIATION_TIMEOUT_SEC;
1140 tv.tv_usec = PROXY_NEGOTIATION_TIMEOUT_USEC;
1141 if (setsockopt(fd, SOL_SOCKET, SO_RCVTIMEO, CS &tv, sizeof(tv)) < 0)
1146 /* The inbound host was declared to be a Proxy Protocol host, so
1147 don't do a PEEK into the data, actually slurp up enough to be
1148 "safe". Can't take it all because TLS-on-connect clients follow
1149 immediately with TLS handshake. */
1150 ret = recv(fd, &hdr, PROXY_INITIAL_READ, 0);
1152 while (ret == -1 && errno == EINTR);
1157 /* For v2, handle reading the length, and then the rest. */
1158 if ((ret == PROXY_INITIAL_READ) && (memcmp(&hdr.v2, v2sig, sizeof(v2sig)) == 0))
1163 /* First get the length fields. */
1166 retmore = recv(fd, (uschar*)&hdr + ret, PROXY_V2_HEADER_SIZE - PROXY_INITIAL_READ, 0);
1167 } while (retmore == -1 && errno == EINTR);
1172 ver = (hdr.v2.ver_cmd & 0xf0) >> 4;
1174 /* May 2014: haproxy combined the version and command into one byte to
1175 allow two full bytes for the length field in order to proxy SSL
1176 connections. SSL Proxy is not supported in this version of Exim, but
1177 must still separate values here. */
1181 DEBUG(D_receive) debug_printf("Invalid Proxy Protocol version: %d\n", ver);
1185 /* The v2 header will always be 16 bytes per the spec. */
1186 size = 16 + ntohs(hdr.v2.len);
1187 DEBUG(D_receive) debug_printf("Detected PROXYv2 header, size %d (limit %d)\n",
1188 size, (int)sizeof(hdr));
1190 /* We should now have 16 octets (PROXY_V2_HEADER_SIZE), and we know the total
1191 amount that we need. Double-check that the size is not unreasonable, then
1193 if (size > sizeof(hdr))
1195 DEBUG(D_receive) debug_printf("PROXYv2 header size unreasonably large; security attack?\n");
1203 retmore = recv(fd, (uschar*)&hdr + ret, size-ret, 0);
1204 } while (retmore == -1 && errno == EINTR);
1208 DEBUG(D_receive) debug_printf("PROXYv2: have %d/%d required octets\n", ret, size);
1209 } while (ret < size);
1211 } /* end scope for getting rest of data for v2 */
1213 /* At this point: if PROXYv2, we've read the exact size required for all data;
1214 if PROXYv1 then we've read "less than required for any valid line" and should
1217 if (ret >= 16 && memcmp(&hdr.v2, v2sig, 12) == 0)
1219 uint8_t cmd = (hdr.v2.ver_cmd & 0x0f);
1223 case 0x01: /* PROXY command */
1226 case 0x11: /* TCPv4 address type */
1228 tmpaddr.sin_addr.s_addr = hdr.v2.addr.ip4.src_addr;
1229 inet_ntop(AF_INET, &tmpaddr.sin_addr, CS &tmpip, sizeof(tmpip));
1230 if (!string_is_ip_address(US tmpip, NULL))
1232 DEBUG(D_receive) debug_printf("Invalid %s source IP\n", iptype);
1235 proxy_local_address = sender_host_address;
1236 sender_host_address = string_copy(US tmpip);
1237 tmpport = ntohs(hdr.v2.addr.ip4.src_port);
1238 proxy_local_port = sender_host_port;
1239 sender_host_port = tmpport;
1240 /* Save dest ip/port */
1241 tmpaddr.sin_addr.s_addr = hdr.v2.addr.ip4.dst_addr;
1242 inet_ntop(AF_INET, &tmpaddr.sin_addr, CS &tmpip, sizeof(tmpip));
1243 if (!string_is_ip_address(US tmpip, NULL))
1245 DEBUG(D_receive) debug_printf("Invalid %s dest port\n", iptype);
1248 proxy_external_address = string_copy(US tmpip);
1249 tmpport = ntohs(hdr.v2.addr.ip4.dst_port);
1250 proxy_external_port = tmpport;
1252 case 0x21: /* TCPv6 address type */
1254 memmove(tmpaddr6.sin6_addr.s6_addr, hdr.v2.addr.ip6.src_addr, 16);
1255 inet_ntop(AF_INET6, &tmpaddr6.sin6_addr, CS &tmpip6, sizeof(tmpip6));
1256 if (!string_is_ip_address(US tmpip6, NULL))
1258 DEBUG(D_receive) debug_printf("Invalid %s source IP\n", iptype);
1261 proxy_local_address = sender_host_address;
1262 sender_host_address = string_copy(US tmpip6);
1263 tmpport = ntohs(hdr.v2.addr.ip6.src_port);
1264 proxy_local_port = sender_host_port;
1265 sender_host_port = tmpport;
1266 /* Save dest ip/port */
1267 memmove(tmpaddr6.sin6_addr.s6_addr, hdr.v2.addr.ip6.dst_addr, 16);
1268 inet_ntop(AF_INET6, &tmpaddr6.sin6_addr, CS &tmpip6, sizeof(tmpip6));
1269 if (!string_is_ip_address(US tmpip6, NULL))
1271 DEBUG(D_receive) debug_printf("Invalid %s dest port\n", iptype);
1274 proxy_external_address = string_copy(US tmpip6);
1275 tmpport = ntohs(hdr.v2.addr.ip6.dst_port);
1276 proxy_external_port = tmpport;
1280 debug_printf("Unsupported PROXYv2 connection type: 0x%02x\n",
1284 /* Unsupported protocol, keep local connection address */
1286 case 0x00: /* LOCAL command */
1287 /* Keep local connection address for LOCAL */
1292 debug_printf("Unsupported PROXYv2 command: 0x%x\n", cmd);
1296 else if (ret >= 8 && memcmp(hdr.v1.line, "PROXY", 5) == 0)
1300 uschar *sp; /* Utility variables follow */
1305 /* get the rest of the line */
1306 r2 = swallow_until_crlf(fd, (uschar*)&hdr, ret, sizeof(hdr)-ret);
1311 p = string_copy(hdr.v1.line);
1312 end = memchr(p, '\r', ret - 1);
1314 if (!end || (end == (uschar*)&hdr + ret) || end[1] != '\n')
1316 DEBUG(D_receive) debug_printf("Partial or invalid PROXY header\n");
1319 *end = '\0'; /* Terminate the string */
1320 size = end + 2 - p; /* Skip header + CRLF */
1321 DEBUG(D_receive) debug_printf("Detected PROXYv1 header\n");
1322 DEBUG(D_receive) debug_printf("Bytes read not within PROXY header: %d\n", ret - size);
1323 /* Step through the string looking for the required fields. Ensure
1324 strict adherence to required formatting, exit for any error. */
1326 if (!isspace(*(p++)))
1328 DEBUG(D_receive) debug_printf("Missing space after PROXY command\n");
1331 if (!Ustrncmp(p, CCS"TCP4", 4))
1333 else if (!Ustrncmp(p,CCS"TCP6", 4))
1335 else if (!Ustrncmp(p,CCS"UNKNOWN", 7))
1337 iptype = US"Unknown";
1342 DEBUG(D_receive) debug_printf("Invalid TCP type\n");
1346 p += Ustrlen(iptype);
1347 if (!isspace(*(p++)))
1349 DEBUG(D_receive) debug_printf("Missing space after TCP4/6 command\n");
1352 /* Find the end of the arg */
1353 if ((sp = Ustrchr(p, ' ')) == NULL)
1356 debug_printf("Did not find proxied src %s\n", iptype);
1360 if(!string_is_ip_address(p, NULL))
1363 debug_printf("Proxied src arg is not an %s address\n", iptype);
1366 proxy_local_address = sender_host_address;
1367 sender_host_address = p;
1369 if ((sp = Ustrchr(p, ' ')) == NULL)
1372 debug_printf("Did not find proxy dest %s\n", iptype);
1376 if(!string_is_ip_address(p, NULL))
1379 debug_printf("Proxy dest arg is not an %s address\n", iptype);
1382 proxy_external_address = p;
1384 if ((sp = Ustrchr(p, ' ')) == NULL)
1386 DEBUG(D_receive) debug_printf("Did not find proxied src port\n");
1390 tmp_port = strtol(CCS p, &endc, 10);
1391 if (*endc || tmp_port == 0)
1394 debug_printf("Proxied src port '%s' not an integer\n", p);
1397 proxy_local_port = sender_host_port;
1398 sender_host_port = tmp_port;
1400 if ((sp = Ustrchr(p, '\0')) == NULL)
1402 DEBUG(D_receive) debug_printf("Did not find proxy dest port\n");
1405 tmp_port = strtol(CCS p, &endc, 10);
1406 if (*endc || tmp_port == 0)
1409 debug_printf("Proxy dest port '%s' not an integer\n", p);
1412 proxy_external_port = tmp_port;
1413 /* Already checked for /r /n above. Good V1 header received. */
1417 /* Wrong protocol */
1418 DEBUG(D_receive) debug_printf("Invalid proxy protocol version negotiation\n");
1419 (void) swallow_until_crlf(fd, (uschar*)&hdr, ret, sizeof(hdr)-ret);
1425 debug_printf("Valid %s sender from Proxy Protocol header\n", iptype);
1426 yield = proxy_session;
1428 /* Don't flush any potential buffer contents. Any input on proxyfail
1429 should cause a synchronization failure */
1432 restore_socket_timeout(fd, get_ok, &tvtmp, vslen);
1437 sender_host_name = NULL;
1438 (void) host_name_lookup();
1439 host_build_sender_fullhost();
1443 proxy_session_failed = TRUE;
1445 debug_printf("Failure to extract proxied host, only QUIT allowed\n");
1452 /*************************************************
1453 * Read one command line *
1454 *************************************************/
1456 /* Strictly, SMTP commands coming over the net are supposed to end with CRLF.
1457 There are sites that don't do this, and in any case internal SMTP probably
1458 should check only for LF. Consequently, we check here for LF only. The line
1459 ends up with [CR]LF removed from its end. If we get an overlong line, treat as
1460 an unknown command. The command is read into the global smtp_cmd_buffer so that
1461 it is available via $smtp_command.
1463 The character reading routine sets up a timeout for each block actually read
1464 from the input (which may contain more than one command). We set up a special
1465 signal handler that closes down the session on a timeout. Control does not
1466 return when it runs.
1469 check_sync if TRUE, check synchronization rules if global option is TRUE
1470 buffer_lim maximum to buffer in lower layer
1472 Returns: a code identifying the command (enumerated above)
1476 smtp_read_command(BOOL check_sync, unsigned buffer_lim)
1481 BOOL hadnull = FALSE;
1483 os_non_restarting_signal(SIGALRM, command_timeout_handler);
1485 while ((c = (receive_getc)(buffer_lim)) != '\n' && c != EOF)
1487 if (ptr >= SMTP_CMD_BUFFER_SIZE)
1489 os_non_restarting_signal(SIGALRM, sigalrm_handler);
1497 smtp_cmd_buffer[ptr++] = c;
1500 receive_linecount++; /* For BSMTP errors */
1501 os_non_restarting_signal(SIGALRM, sigalrm_handler);
1503 /* If hit end of file, return pseudo EOF command. Whether we have a
1504 part-line already read doesn't matter, since this is an error state. */
1506 if (c == EOF) return EOF_CMD;
1508 /* Remove any CR and white space at the end of the line, and terminate the
1511 while (ptr > 0 && isspace(smtp_cmd_buffer[ptr-1])) ptr--;
1512 smtp_cmd_buffer[ptr] = 0;
1514 DEBUG(D_receive) debug_printf("SMTP<< %s\n", smtp_cmd_buffer);
1516 /* NULLs are not allowed in SMTP commands */
1518 if (hadnull) return BADCHAR_CMD;
1520 /* Scan command list and return identity, having set the data pointer
1521 to the start of the actual data characters. Check for SMTP synchronization
1524 for (p = cmd_list; p < cmd_list_end; p++)
1526 #ifdef SUPPORT_PROXY
1527 /* Only allow QUIT command if Proxy Protocol parsing failed */
1528 if (proxy_session && proxy_session_failed && p->cmd != QUIT_CMD)
1532 && strncmpic(smtp_cmd_buffer, US p->name, p->len) == 0
1533 && ( smtp_cmd_buffer[p->len-1] == ':' /* "mail from:" or "rcpt to:" */
1534 || smtp_cmd_buffer[p->len] == 0
1535 || smtp_cmd_buffer[p->len] == ' '
1538 if (smtp_inptr < smtp_inend && /* Outstanding input */
1539 p->cmd < sync_cmd_limit && /* Command should sync */
1540 check_sync && /* Local flag set */
1541 smtp_enforce_sync && /* Global flag set */
1542 sender_host_address != NULL && /* Not local input */
1543 !sender_host_notsocket) /* Really is a socket */
1546 /* The variables $smtp_command and $smtp_command_argument point into the
1547 unmodified input buffer. A copy of the latter is taken for actual
1548 processing, so that it can be chopped up into separate parts if necessary,
1549 for example, when processing a MAIL command options such as SIZE that can
1550 follow the sender address. */
1552 smtp_cmd_argument = smtp_cmd_buffer + p->len;
1553 while (isspace(*smtp_cmd_argument)) smtp_cmd_argument++;
1554 Ustrcpy(smtp_data_buffer, smtp_cmd_argument);
1555 smtp_cmd_data = smtp_data_buffer;
1557 /* Count non-mail commands from those hosts that are controlled in this
1558 way. The default is all hosts. We don't waste effort checking the list
1559 until we get a non-mail command, but then cache the result to save checking
1560 again. If there's a DEFER while checking the host, assume it's in the list.
1562 Note that one instance of RSET, EHLO/HELO, and STARTTLS is allowed at the
1563 start of each incoming message by fiddling with the value in the table. */
1565 if (!p->is_mail_cmd)
1567 if (count_nonmail == TRUE_UNSET) count_nonmail =
1568 verify_check_host(&smtp_accept_max_nonmail_hosts) != FAIL;
1569 if (count_nonmail && ++nonmail_command_count > smtp_accept_max_nonmail)
1570 return TOO_MANY_NONMAIL_CMD;
1573 /* If there is data for a command that does not expect it, generate the
1576 return (p->has_arg || *smtp_cmd_data == 0)? p->cmd : BADARG_CMD;
1580 #ifdef SUPPORT_PROXY
1581 /* Only allow QUIT command if Proxy Protocol parsing failed */
1582 if (proxy_session && proxy_session_failed)
1583 return PROXY_FAIL_IGNORE_CMD;
1586 /* Enforce synchronization for unknown commands */
1588 if (smtp_inptr < smtp_inend && /* Outstanding input */
1589 check_sync && /* Local flag set */
1590 smtp_enforce_sync && /* Global flag set */
1591 sender_host_address != NULL && /* Not local input */
1592 !sender_host_notsocket) /* Really is a socket */
1600 /*************************************************
1601 * Forced closedown of call *
1602 *************************************************/
1604 /* This function is called from log.c when Exim is dying because of a serious
1605 disaster, and also from some other places. If an incoming non-batched SMTP
1606 channel is open, it swallows the rest of the incoming message if in the DATA
1607 phase, sends the reply string, and gives an error to all subsequent commands
1608 except QUIT. The existence of an SMTP call is detected by the non-NULLness of
1612 message SMTP reply string to send, excluding the code
1618 smtp_closedown(uschar *message)
1620 if (smtp_in == NULL || smtp_batched_input) return;
1621 receive_swallow_smtp();
1622 smtp_printf("421 %s\r\n", message);
1624 for (;;) switch(smtp_read_command(FALSE, GETC_BUFFER_UNLIMITED))
1630 smtp_printf("221 %s closing connection\r\n", smtp_active_hostname);
1635 smtp_printf("250 Reset OK\r\n");
1639 smtp_printf("421 %s\r\n", message);
1647 /*************************************************
1648 * Set up connection info for logging *
1649 *************************************************/
1651 /* This function is called when logging information about an SMTP connection.
1652 It sets up appropriate source information, depending on the type of connection.
1653 If sender_fullhost is NULL, we are at a very early stage of the connection;
1654 just use the IP address.
1657 Returns: a string describing the connection
1661 smtp_get_connection_info(void)
1663 const uschar * hostname = sender_fullhost
1664 ? sender_fullhost : sender_host_address;
1667 return string_sprintf("SMTP connection from %s", hostname);
1669 if (sender_host_unknown || sender_host_notsocket)
1670 return string_sprintf("SMTP connection from %s", sender_ident);
1673 return string_sprintf("SMTP connection from %s (via inetd)", hostname);
1675 if (LOGGING(incoming_interface) && interface_address != NULL)
1676 return string_sprintf("SMTP connection from %s I=[%s]:%d", hostname,
1677 interface_address, interface_port);
1679 return string_sprintf("SMTP connection from %s", hostname);
1685 /* Append TLS-related information to a log line
1688 s String under construction: allocated string to extend, or NULL
1689 sizep Pointer to current allocation size (update on return), or NULL
1690 ptrp Pointer to index for new entries in string (update on return), or NULL
1692 Returns: Allocated string or NULL
1695 s_tlslog(uschar * s, int * sizep, int * ptrp)
1697 int size = sizep ? *sizep : 0;
1698 int ptr = ptrp ? *ptrp : 0;
1700 if (LOGGING(tls_cipher) && tls_in.cipher != NULL)
1701 s = string_append(s, &size, &ptr, 2, US" X=", tls_in.cipher);
1702 if (LOGGING(tls_certificate_verified) && tls_in.cipher != NULL)
1703 s = string_append(s, &size, &ptr, 2, US" CV=",
1704 tls_in.certificate_verified? "yes":"no");
1705 if (LOGGING(tls_peerdn) && tls_in.peerdn != NULL)
1706 s = string_append(s, &size, &ptr, 3, US" DN=\"",
1707 string_printing(tls_in.peerdn), US"\"");
1708 if (LOGGING(tls_sni) && tls_in.sni != NULL)
1709 s = string_append(s, &size, &ptr, 3, US" SNI=\"",
1710 string_printing(tls_in.sni), US"\"");
1715 if (sizep) *sizep = size;
1716 if (ptrp) *ptrp = ptr;
1722 /*************************************************
1723 * Log lack of MAIL if so configured *
1724 *************************************************/
1726 /* This function is called when an SMTP session ends. If the log selector
1727 smtp_no_mail is set, write a log line giving some details of what has happened
1728 in the SMTP session.
1735 smtp_log_no_mail(void)
1740 if (smtp_mailcmd_count > 0 || !LOGGING(smtp_no_mail))
1746 if (sender_host_authenticated != NULL)
1748 s = string_append(s, &size, &ptr, 2, US" A=", sender_host_authenticated);
1749 if (authenticated_id != NULL)
1750 s = string_append(s, &size, &ptr, 2, US":", authenticated_id);
1754 s = s_tlslog(s, &size, &ptr);
1757 sep = (smtp_connection_had[SMTP_HBUFF_SIZE-1] != SCH_NONE)?
1758 US" C=..." : US" C=";
1759 for (i = smtp_ch_index; i < SMTP_HBUFF_SIZE; i++)
1761 if (smtp_connection_had[i] != SCH_NONE)
1763 s = string_append(s, &size, &ptr, 2, sep,
1764 smtp_names[smtp_connection_had[i]]);
1769 for (i = 0; i < smtp_ch_index; i++)
1771 s = string_append(s, &size, &ptr, 2, sep, smtp_names[smtp_connection_had[i]]);
1775 if (s != NULL) s[ptr] = 0; else s = US"";
1776 log_write(0, LOG_MAIN, "no MAIL in SMTP connection from %s D=%s%s",
1777 host_and_ident(FALSE),
1778 readconf_printtime( (int) ((long)time(NULL) - (long)smtp_connection_start)),
1784 /*************************************************
1785 * Check HELO line and set sender_helo_name *
1786 *************************************************/
1788 /* Check the format of a HELO line. The data for HELO/EHLO is supposed to be
1789 the domain name of the sending host, or an ip literal in square brackets. The
1790 argument is placed in sender_helo_name, which is in malloc store, because it
1791 must persist over multiple incoming messages. If helo_accept_junk is set, this
1792 host is permitted to send any old junk (needed for some broken hosts).
1793 Otherwise, helo_allow_chars can be used for rogue characters in general
1794 (typically people want to let in underscores).
1797 s the data portion of the line (already past any white space)
1799 Returns: TRUE or FALSE
1803 check_helo(uschar *s)
1806 uschar *end = s + Ustrlen(s);
1807 BOOL yield = helo_accept_junk;
1809 /* Discard any previous helo name */
1811 if (sender_helo_name != NULL)
1813 store_free(sender_helo_name);
1814 sender_helo_name = NULL;
1817 /* Skip tests if junk is permitted. */
1821 /* Allow the new standard form for IPv6 address literals, namely,
1822 [IPv6:....], and because someone is bound to use it, allow an equivalent
1823 IPv4 form. Allow plain addresses as well. */
1830 if (strncmpic(s, US"[IPv6:", 6) == 0)
1831 yield = (string_is_ip_address(s+6, NULL) == 6);
1832 else if (strncmpic(s, US"[IPv4:", 6) == 0)
1833 yield = (string_is_ip_address(s+6, NULL) == 4);
1835 yield = (string_is_ip_address(s+1, NULL) != 0);
1840 /* Non-literals must be alpha, dot, hyphen, plus any non-valid chars
1841 that have been configured (usually underscore - sigh). */
1848 if (!isalnum(*s) && *s != '.' && *s != '-' &&
1849 Ustrchr(helo_allow_chars, *s) == NULL)
1859 /* Save argument if OK */
1861 if (yield) sender_helo_name = string_copy_malloc(start);
1869 /*************************************************
1870 * Extract SMTP command option *
1871 *************************************************/
1873 /* This function picks the next option setting off the end of smtp_cmd_data. It
1874 is called for MAIL FROM and RCPT TO commands, to pick off the optional ESMTP
1875 things that can appear there.
1878 name point this at the name
1879 value point this at the data string
1881 Returns: TRUE if found an option
1885 extract_option(uschar **name, uschar **value)
1888 uschar *v = smtp_cmd_data + Ustrlen(smtp_cmd_data) - 1;
1889 while (isspace(*v)) v--;
1891 while (v > smtp_cmd_data && *v != '=' && !isspace(*v))
1893 /* Take care to not stop at a space embedded in a quoted local-part */
1895 if (*v == '"') do v--; while (*v != '"' && v > smtp_cmd_data+1);
1902 while(isalpha(n[-1])) n--;
1903 /* RFC says SP, but TAB seen in wild and other major MTAs accept it */
1904 if (!isspace(n[-1])) return FALSE;
1910 if (v == smtp_cmd_data) return FALSE;
1922 /*************************************************
1923 * Reset for new message *
1924 *************************************************/
1926 /* This function is called whenever the SMTP session is reset from
1927 within either of the setup functions.
1929 Argument: the stacking pool storage reset point
1934 smtp_reset(void *reset_point)
1936 recipients_list = NULL;
1937 rcpt_count = rcpt_defer_count = rcpt_fail_count =
1938 raw_recipients_count = recipients_count = recipients_list_max = 0;
1939 message_linecount = 0;
1941 acl_added_headers = NULL;
1942 acl_removed_headers = NULL;
1943 queue_only_policy = FALSE;
1944 rcpt_smtp_response = NULL;
1945 rcpt_smtp_response_same = TRUE;
1946 rcpt_in_progress = FALSE;
1947 deliver_freeze = FALSE; /* Can be set by ACL */
1948 freeze_tell = freeze_tell_config; /* Can be set by ACL */
1949 fake_response = OK; /* Can be set by ACL */
1950 #ifdef WITH_CONTENT_SCAN
1951 no_mbox_unspool = FALSE; /* Can be set by ACL */
1953 submission_mode = FALSE; /* Can be set by ACL */
1954 suppress_local_fixups = suppress_local_fixups_default; /* Can be set by ACL */
1955 active_local_from_check = local_from_check; /* Can be set by ACL */
1956 active_local_sender_retain = local_sender_retain; /* Can be set by ACL */
1957 sending_ip_address = NULL;
1958 return_path = sender_address = NULL;
1959 sender_data = NULL; /* Can be set by ACL */
1960 deliver_localpart_orig = NULL;
1961 deliver_domain_orig = NULL;
1962 callout_address = NULL;
1963 submission_name = NULL; /* Can be set by ACL */
1964 raw_sender = NULL; /* After SMTP rewrite, before qualifying */
1965 sender_address_unrewritten = NULL; /* Set only after verify rewrite */
1966 sender_verified_list = NULL; /* No senders verified */
1967 memset(sender_address_cache, 0, sizeof(sender_address_cache));
1968 memset(sender_domain_cache, 0, sizeof(sender_domain_cache));
1970 authenticated_sender = NULL;
1971 #ifdef EXPERIMENTAL_BRIGHTMAIL
1973 bmi_verdicts = NULL;
1975 dnslist_domain = dnslist_matched = NULL;
1976 #ifndef DISABLE_DKIM
1977 dkim_signers = NULL;
1978 dkim_disable_verify = FALSE;
1979 dkim_collect_input = FALSE;
1983 deliver_host = deliver_host_address = NULL; /* Can be set by ACL */
1984 #ifndef DISABLE_PRDR
1985 prdr_requested = FALSE;
1987 #ifdef EXPERIMENTAL_SPF
1988 spf_header_comment = NULL;
1989 spf_received = NULL;
1991 spf_smtp_comment = NULL;
1994 message_smtputf8 = FALSE;
1996 body_linecount = body_zerocount = 0;
1998 sender_rate = sender_rate_limit = sender_rate_period = NULL;
1999 ratelimiters_mail = NULL; /* Updated by ratelimit ACL condition */
2000 /* Note that ratelimiters_conn persists across resets. */
2002 /* Reset message ACL variables */
2006 /* The message body variables use malloc store. They may be set if this is
2007 not the first message in an SMTP session and the previous message caused them
2008 to be referenced in an ACL. */
2012 store_free(message_body);
2013 message_body = NULL;
2016 if (message_body_end)
2018 store_free(message_body_end);
2019 message_body_end = NULL;
2022 /* Warning log messages are also saved in malloc store. They are saved to avoid
2023 repetition in the same message, but it seems right to repeat them for different
2026 while (acl_warn_logged)
2028 string_item *this = acl_warn_logged;
2029 acl_warn_logged = acl_warn_logged->next;
2032 store_reset(reset_point);
2039 /*************************************************
2040 * Initialize for incoming batched SMTP message *
2041 *************************************************/
2043 /* This function is called from smtp_setup_msg() in the case when
2044 smtp_batched_input is true. This happens when -bS is used to pass a whole batch
2045 of messages in one file with SMTP commands between them. All errors must be
2046 reported by sending a message, and only MAIL FROM, RCPT TO, and DATA are
2047 relevant. After an error on a sender, or an invalid recipient, the remainder
2048 of the message is skipped. The value of received_protocol is already set.
2051 Returns: > 0 message successfully started (reached DATA)
2052 = 0 QUIT read or end of file reached
2053 < 0 should not occur
2057 smtp_setup_batch_msg(void)
2060 void *reset_point = store_get(0);
2062 /* Save the line count at the start of each transaction - single commands
2063 like HELO and RSET count as whole transactions. */
2065 bsmtp_transaction_linecount = receive_linecount;
2067 if ((receive_feof)()) return 0; /* Treat EOF as QUIT */
2069 cancel_cutthrough_connection(TRUE, US"smtp_setup_batch_msg");
2070 smtp_reset(reset_point); /* Reset for start of message */
2072 /* Deal with SMTP commands. This loop is exited by setting done to a POSITIVE
2073 value. The values are 2 larger than the required yield of the function. */
2078 uschar *recipient = NULL;
2079 int start, end, sender_domain, recipient_domain;
2081 switch(smtp_read_command(FALSE, GETC_BUFFER_UNLIMITED))
2083 /* The HELO/EHLO commands set sender_address_helo if they have
2084 valid data; otherwise they are ignored, except that they do
2085 a reset of the state. */
2090 check_helo(smtp_cmd_data);
2094 cancel_cutthrough_connection(TRUE, US"RSET received");
2095 smtp_reset(reset_point);
2096 bsmtp_transaction_linecount = receive_linecount;
2100 /* The MAIL FROM command requires an address as an operand. All we
2101 do here is to parse it for syntactic correctness. The form "<>" is
2102 a special case which converts into an empty string. The start/end
2103 pointers in the original are not used further for this address, as
2104 it is the canonical extracted address which is all that is kept. */
2107 smtp_mailcmd_count++; /* Count for no-mail log */
2108 if (sender_address != NULL)
2109 /* The function moan_smtp_batch() does not return. */
2110 moan_smtp_batch(smtp_cmd_buffer, "503 Sender already given");
2112 if (smtp_cmd_data[0] == 0)
2113 /* The function moan_smtp_batch() does not return. */
2114 moan_smtp_batch(smtp_cmd_buffer, "501 MAIL FROM must have an address operand");
2116 /* Reset to start of message */
2118 cancel_cutthrough_connection(TRUE, US"MAIL received");
2119 smtp_reset(reset_point);
2121 /* Apply SMTP rewrite */
2123 raw_sender = ((rewrite_existflags & rewrite_smtp) != 0)?
2124 rewrite_one(smtp_cmd_data, rewrite_smtp|rewrite_smtp_sender, NULL, FALSE,
2125 US"", global_rewrite_rules) : smtp_cmd_data;
2127 /* Extract the address; the TRUE flag allows <> as valid */
2130 parse_extract_address(raw_sender, &errmess, &start, &end, &sender_domain,
2133 if (raw_sender == NULL)
2134 /* The function moan_smtp_batch() does not return. */
2135 moan_smtp_batch(smtp_cmd_buffer, "501 %s", errmess);
2137 sender_address = string_copy(raw_sender);
2139 /* Qualify unqualified sender addresses if permitted to do so. */
2141 if (sender_domain == 0 && sender_address[0] != 0 && sender_address[0] != '@')
2143 if (allow_unqualified_sender)
2145 sender_address = rewrite_address_qualify(sender_address, FALSE);
2146 DEBUG(D_receive) debug_printf("unqualified address %s accepted "
2147 "and rewritten\n", raw_sender);
2149 /* The function moan_smtp_batch() does not return. */
2150 else moan_smtp_batch(smtp_cmd_buffer, "501 sender address must contain "
2156 /* The RCPT TO command requires an address as an operand. All we do
2157 here is to parse it for syntactic correctness. There may be any number
2158 of RCPT TO commands, specifying multiple senders. We build them all into
2159 a data structure that is in argc/argv format. The start/end values
2160 given by parse_extract_address are not used, as we keep only the
2161 extracted address. */
2164 if (sender_address == NULL)
2165 /* The function moan_smtp_batch() does not return. */
2166 moan_smtp_batch(smtp_cmd_buffer, "503 No sender yet given");
2168 if (smtp_cmd_data[0] == 0)
2169 /* The function moan_smtp_batch() does not return. */
2170 moan_smtp_batch(smtp_cmd_buffer, "501 RCPT TO must have an address operand");
2172 /* Check maximum number allowed */
2174 if (recipients_max > 0 && recipients_count + 1 > recipients_max)
2175 /* The function moan_smtp_batch() does not return. */
2176 moan_smtp_batch(smtp_cmd_buffer, "%s too many recipients",
2177 recipients_max_reject? "552": "452");
2179 /* Apply SMTP rewrite, then extract address. Don't allow "<>" as a
2180 recipient address */
2182 recipient = rewrite_existflags & rewrite_smtp
2183 ? rewrite_one(smtp_cmd_data, rewrite_smtp, NULL, FALSE, US"",
2184 global_rewrite_rules)
2187 recipient = parse_extract_address(recipient, &errmess, &start, &end,
2188 &recipient_domain, FALSE);
2191 /* The function moan_smtp_batch() does not return. */
2192 moan_smtp_batch(smtp_cmd_buffer, "501 %s", errmess);
2194 /* If the recipient address is unqualified, qualify it if permitted. Then
2195 add it to the list of recipients. */
2197 if (recipient_domain == 0)
2199 if (allow_unqualified_recipient)
2201 DEBUG(D_receive) debug_printf("unqualified address %s accepted\n",
2203 recipient = rewrite_address_qualify(recipient, TRUE);
2205 /* The function moan_smtp_batch() does not return. */
2206 else moan_smtp_batch(smtp_cmd_buffer, "501 recipient address must contain "
2209 receive_add_recipient(recipient, -1);
2213 /* The DATA command is legal only if it follows successful MAIL FROM
2214 and RCPT TO commands. This function is complete when a valid DATA
2215 command is encountered. */
2218 if (sender_address == NULL || recipients_count <= 0)
2220 /* The function moan_smtp_batch() does not return. */
2221 if (sender_address == NULL)
2222 moan_smtp_batch(smtp_cmd_buffer,
2223 "503 MAIL FROM:<sender> command must precede DATA");
2225 moan_smtp_batch(smtp_cmd_buffer,
2226 "503 RCPT TO:<recipient> must precede DATA");
2230 done = 3; /* DATA successfully achieved */
2231 message_ended = END_NOTENDED; /* Indicate in middle of message */
2236 /* The VRFY, EXPN, HELP, ETRN, and NOOP commands are ignored. */
2243 bsmtp_transaction_linecount = receive_linecount;
2254 /* The function moan_smtp_batch() does not return. */
2255 moan_smtp_batch(smtp_cmd_buffer, "501 Unexpected argument data");
2260 /* The function moan_smtp_batch() does not return. */
2261 moan_smtp_batch(smtp_cmd_buffer, "501 Unexpected NULL in SMTP command");
2266 /* The function moan_smtp_batch() does not return. */
2267 moan_smtp_batch(smtp_cmd_buffer, "500 Command unrecognized");
2272 return done - 2; /* Convert yield values */
2279 smtp_log_tls_fail(uschar * errstr)
2281 uschar * conn_info = smtp_get_connection_info();
2283 if (Ustrncmp(conn_info, US"SMTP ", 5) == 0) conn_info += 5;
2284 /* I'd like to get separated H= here, but too hard for now */
2286 log_write(0, LOG_MAIN, "TLS error on %s %s", conn_info, errstr);
2291 /*************************************************
2292 * Start an SMTP session *
2293 *************************************************/
2295 /* This function is called at the start of an SMTP session. Thereafter,
2296 smtp_setup_msg() is called to initiate each separate message. This
2297 function does host-specific testing, and outputs the banner line.
2300 Returns: FALSE if the session can not continue; something has
2301 gone wrong, or the connection to the host is blocked
2305 smtp_start_session(void)
2309 uschar *user_msg, *log_msg;
2313 smtp_connection_start = time(NULL);
2314 for (smtp_ch_index = 0; smtp_ch_index < SMTP_HBUFF_SIZE; smtp_ch_index++)
2315 smtp_connection_had[smtp_ch_index] = SCH_NONE;
2318 /* Default values for certain variables */
2320 helo_seen = esmtp = helo_accept_junk = FALSE;
2321 smtp_mailcmd_count = 0;
2322 count_nonmail = TRUE_UNSET;
2323 synprot_error_count = unknown_command_count = nonmail_command_count = 0;
2324 smtp_delay_mail = smtp_rlm_base;
2325 auth_advertised = FALSE;
2326 pipelining_advertised = FALSE;
2327 pipelining_enable = TRUE;
2328 sync_cmd_limit = NON_SYNC_CMD_NON_PIPELINING;
2329 smtp_exit_function_called = FALSE; /* For avoiding loop in not-quit exit */
2331 /* If receiving by -bs from a trusted user, or testing with -bh, we allow
2332 authentication settings from -oMaa to remain in force. */
2334 if (!host_checking && !sender_host_notsocket) sender_host_authenticated = NULL;
2335 authenticated_by = NULL;
2338 tls_in.cipher = tls_in.peerdn = NULL;
2339 tls_in.ourcert = tls_in.peercert = NULL;
2341 tls_in.ocsp = OCSP_NOT_REQ;
2342 tls_advertised = FALSE;
2344 dsn_advertised = FALSE;
2346 smtputf8_advertised = FALSE;
2349 /* Reset ACL connection variables */
2353 /* Allow for trailing 0 in the command and data buffers. */
2355 if (!(smtp_cmd_buffer = US malloc(2*SMTP_CMD_BUFFER_SIZE + 2)))
2356 log_write(0, LOG_MAIN|LOG_PANIC_DIE,
2357 "malloc() failed for SMTP command buffer");
2359 smtp_cmd_buffer[0] = 0;
2360 smtp_data_buffer = smtp_cmd_buffer + SMTP_CMD_BUFFER_SIZE + 1;
2362 /* For batched input, the protocol setting can be overridden from the
2363 command line by a trusted caller. */
2365 if (smtp_batched_input)
2367 if (!received_protocol) received_protocol = US"local-bsmtp";
2370 /* For non-batched SMTP input, the protocol setting is forced here. It will be
2371 reset later if any of EHLO/AUTH/STARTTLS are received. */
2375 (sender_host_address ? protocols : protocols_local) [pnormal];
2377 /* Set up the buffer for inputting using direct read() calls, and arrange to
2378 call the local functions instead of the standard C ones. */
2380 if (!(smtp_inbuffer = (uschar *)malloc(IN_BUFFER_SIZE)))
2381 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "malloc() failed for SMTP input buffer");
2383 receive_getc = smtp_getc;
2384 receive_getbuf = smtp_getbuf;
2385 receive_get_cache = smtp_get_cache;
2386 receive_ungetc = smtp_ungetc;
2387 receive_feof = smtp_feof;
2388 receive_ferror = smtp_ferror;
2389 receive_smtp_buffered = smtp_buffered;
2390 smtp_inptr = smtp_inend = smtp_inbuffer;
2391 smtp_had_eof = smtp_had_error = 0;
2393 /* Set up the message size limit; this may be host-specific */
2395 thismessage_size_limit = expand_string_integer(message_size_limit, TRUE);
2396 if (expand_string_message != NULL)
2398 if (thismessage_size_limit == -1)
2399 log_write(0, LOG_MAIN|LOG_PANIC, "unable to expand message_size_limit: "
2400 "%s", expand_string_message);
2402 log_write(0, LOG_MAIN|LOG_PANIC, "invalid message_size_limit: "
2403 "%s", expand_string_message);
2404 smtp_closedown(US"Temporary local problem - please try later");
2408 /* When a message is input locally via the -bs or -bS options, sender_host_
2409 unknown is set unless -oMa was used to force an IP address, in which case it
2410 is checked like a real remote connection. When -bs is used from inetd, this
2411 flag is not set, causing the sending host to be checked. The code that deals
2412 with IP source routing (if configured) is never required for -bs or -bS and
2413 the flag sender_host_notsocket is used to suppress it.
2415 If smtp_accept_max and smtp_accept_reserve are set, keep some connections in
2416 reserve for certain hosts and/or networks. */
2418 if (!sender_host_unknown)
2421 BOOL reserved_host = FALSE;
2423 /* Look up IP options (source routing info) on the socket if this is not an
2424 -oMa "host", and if any are found, log them and drop the connection.
2426 Linux (and others now, see below) is different to everyone else, so there
2427 has to be some conditional compilation here. Versions of Linux before 2.1.15
2428 used a structure whose name was "options". Somebody finally realized that
2429 this name was silly, and it got changed to "ip_options". I use the
2430 newer name here, but there is a fudge in the script that sets up os.h
2431 to define a macro in older Linux systems.
2433 Sigh. Linux is a fast-moving target. Another generation of Linux uses
2434 glibc 2, which has chosen ip_opts for the structure name. This is now
2435 really a glibc thing rather than a Linux thing, so the condition name
2436 has been changed to reflect this. It is relevant also to GNU/Hurd.
2438 Mac OS 10.x (Darwin) is like the later glibc versions, but without the
2439 setting of the __GLIBC__ macro, so we can't detect it automatically. There's
2440 a special macro defined in the os.h file.
2442 Some DGUX versions on older hardware appear not to support IP options at
2443 all, so there is now a general macro which can be set to cut out this
2446 How to do this properly in IPv6 is not yet known. */
2448 #if !HAVE_IPV6 && !defined(NO_IP_OPTIONS)
2450 #ifdef GLIBC_IP_OPTIONS
2451 #if (!defined __GLIBC__) || (__GLIBC__ < 2)
2456 #elif defined DARWIN_IP_OPTIONS
2462 if (!host_checking && !sender_host_notsocket)
2465 EXIM_SOCKLEN_T optlen = sizeof(struct ip_options) + MAX_IPOPTLEN;
2466 struct ip_options *ipopt = store_get(optlen);
2468 struct ip_opts ipoptblock;
2469 struct ip_opts *ipopt = &ipoptblock;
2470 EXIM_SOCKLEN_T optlen = sizeof(ipoptblock);
2472 struct ipoption ipoptblock;
2473 struct ipoption *ipopt = &ipoptblock;
2474 EXIM_SOCKLEN_T optlen = sizeof(ipoptblock);
2477 /* Occasional genuine failures of getsockopt() have been seen - for
2478 example, "reset by peer". Therefore, just log and give up on this
2479 call, unless the error is ENOPROTOOPT. This error is given by systems
2480 that have the interfaces but not the mechanism - e.g. GNU/Hurd at the time
2481 of writing. So for that error, carry on - we just can't do an IP options
2484 DEBUG(D_receive) debug_printf("checking for IP options\n");
2486 if (getsockopt(fileno(smtp_out), IPPROTO_IP, IP_OPTIONS, (uschar *)(ipopt),
2489 if (errno != ENOPROTOOPT)
2491 log_write(0, LOG_MAIN, "getsockopt() failed from %s: %s",
2492 host_and_ident(FALSE), strerror(errno));
2493 smtp_printf("451 SMTP service not available\r\n");
2498 /* Deal with any IP options that are set. On the systems I have looked at,
2499 the value of MAX_IPOPTLEN has been 40, meaning that there should never be
2500 more logging data than will fit in big_buffer. Nevertheless, after somebody
2501 questioned this code, I've added in some paranoid checking. */
2503 else if (optlen > 0)
2505 uschar *p = big_buffer;
2506 uschar *pend = big_buffer + big_buffer_size;
2507 uschar *opt, *adptr;
2509 struct in_addr addr;
2512 uschar *optstart = (uschar *)(ipopt->__data);
2514 uschar *optstart = (uschar *)(ipopt->ip_opts);
2516 uschar *optstart = (uschar *)(ipopt->ipopt_list);
2519 DEBUG(D_receive) debug_printf("IP options exist\n");
2521 Ustrcpy(p, "IP options on incoming call:");
2524 for (opt = optstart; opt != NULL &&
2525 opt < (uschar *)(ipopt) + optlen;)
2539 if (!string_format(p, pend-p, " %s [@%s",
2540 (*opt == IPOPT_SSRR)? "SSRR" : "LSRR",
2542 inet_ntoa(*((struct in_addr *)(&(ipopt->faddr))))))
2544 inet_ntoa(ipopt->ip_dst)))
2546 inet_ntoa(ipopt->ipopt_dst)))
2554 optcount = (opt[1] - 3) / sizeof(struct in_addr);
2556 while (optcount-- > 0)
2558 memcpy(&addr, adptr, sizeof(addr));
2559 if (!string_format(p, pend - p - 1, "%s%s",
2560 (optcount == 0)? ":" : "@", inet_ntoa(addr)))
2566 adptr += sizeof(struct in_addr);
2575 if (pend - p < 4 + 3*opt[1]) { opt = NULL; break; }
2578 for (i = 0; i < opt[1]; i++)
2580 sprintf(CS p, "%2.2x ", opt[i]);
2591 log_write(0, LOG_MAIN, "%s", big_buffer);
2593 /* Refuse any call with IP options. This is what tcpwrappers 7.5 does. */
2595 log_write(0, LOG_MAIN|LOG_REJECT,
2596 "connection from %s refused (IP options)", host_and_ident(FALSE));
2598 smtp_printf("554 SMTP service not available\r\n");
2602 /* Length of options = 0 => there are no options */
2604 else DEBUG(D_receive) debug_printf("no IP options found\n");
2606 #endif /* HAVE_IPV6 && !defined(NO_IP_OPTIONS) */
2608 /* Set keep-alive in socket options. The option is on by default. This
2609 setting is an attempt to get rid of some hanging connections that stick in
2610 read() when the remote end (usually a dialup) goes away. */
2612 if (smtp_accept_keepalive && !sender_host_notsocket)
2613 ip_keepalive(fileno(smtp_out), sender_host_address, FALSE);
2615 /* If the current host matches host_lookup, set the name by doing a
2616 reverse lookup. On failure, sender_host_name will be NULL and
2617 host_lookup_failed will be TRUE. This may or may not be serious - optional
2620 if (verify_check_host(&host_lookup) == OK)
2622 (void)host_name_lookup();
2623 host_build_sender_fullhost();
2626 /* Delay this until we have the full name, if it is looked up. */
2628 set_process_info("handling incoming connection from %s",
2629 host_and_ident(FALSE));
2631 /* Expand smtp_receive_timeout, if needed */
2633 if (smtp_receive_timeout_s)
2636 if ( !(exp = expand_string(smtp_receive_timeout_s))
2638 || (smtp_receive_timeout = readconf_readtime(exp, 0, FALSE)) < 0
2640 log_write(0, LOG_MAIN|LOG_PANIC,
2641 "bad value for smtp_receive_timeout: '%s'", exp ? exp : US"");
2644 /* Test for explicit connection rejection */
2646 if (verify_check_host(&host_reject_connection) == OK)
2648 log_write(L_connection_reject, LOG_MAIN|LOG_REJECT, "refused connection "
2649 "from %s (host_reject_connection)", host_and_ident(FALSE));
2650 smtp_printf("554 SMTP service not available\r\n");
2654 /* Test with TCP Wrappers if so configured. There is a problem in that
2655 hosts_ctl() returns 0 (deny) under a number of system failure circumstances,
2656 such as disks dying. In these cases, it is desirable to reject with a 4xx
2657 error instead of a 5xx error. There isn't a "right" way to detect such
2658 problems. The following kludge is used: errno is zeroed before calling
2659 hosts_ctl(). If the result is "reject", a 5xx error is given only if the
2660 value of errno is 0 or ENOENT (which happens if /etc/hosts.{allow,deny} does
2663 #ifdef USE_TCP_WRAPPERS
2665 if (!(tcp_wrappers_name = expand_string(tcp_wrappers_daemon_name)))
2666 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "Expansion of \"%s\" "
2667 "(tcp_wrappers_name) failed: %s", string_printing(tcp_wrappers_name),
2668 expand_string_message);
2670 if (!hosts_ctl(tcp_wrappers_name,
2671 sender_host_name ? CS sender_host_name : STRING_UNKNOWN,
2672 sender_host_address ? CS sender_host_address : STRING_UNKNOWN,
2673 sender_ident ? CS sender_ident : STRING_UNKNOWN))
2675 if (errno == 0 || errno == ENOENT)
2677 HDEBUG(D_receive) debug_printf("tcp wrappers rejection\n");
2678 log_write(L_connection_reject,
2679 LOG_MAIN|LOG_REJECT, "refused connection from %s "
2680 "(tcp wrappers)", host_and_ident(FALSE));
2681 smtp_printf("554 SMTP service not available\r\n");
2685 int save_errno = errno;
2686 HDEBUG(D_receive) debug_printf("tcp wrappers rejected with unexpected "
2687 "errno value %d\n", save_errno);
2688 log_write(L_connection_reject,
2689 LOG_MAIN|LOG_REJECT, "temporarily refused connection from %s "
2690 "(tcp wrappers errno=%d)", host_and_ident(FALSE), save_errno);
2691 smtp_printf("451 Temporary local problem - please try later\r\n");
2697 /* Check for reserved slots. The value of smtp_accept_count has already been
2698 incremented to include this process. */
2700 if (smtp_accept_max > 0 &&
2701 smtp_accept_count > smtp_accept_max - smtp_accept_reserve)
2703 if ((rc = verify_check_host(&smtp_reserve_hosts)) != OK)
2705 log_write(L_connection_reject,
2706 LOG_MAIN, "temporarily refused connection from %s: not in "
2707 "reserve list: connected=%d max=%d reserve=%d%s",
2708 host_and_ident(FALSE), smtp_accept_count - 1, smtp_accept_max,
2709 smtp_accept_reserve, (rc == DEFER)? " (lookup deferred)" : "");
2710 smtp_printf("421 %s: Too many concurrent SMTP connections; "
2711 "please try again later\r\n", smtp_active_hostname);
2714 reserved_host = TRUE;
2717 /* If a load level above which only messages from reserved hosts are
2718 accepted is set, check the load. For incoming calls via the daemon, the
2719 check is done in the superior process if there are no reserved hosts, to
2720 save a fork. In all cases, the load average will already be available
2721 in a global variable at this point. */
2723 if (smtp_load_reserve >= 0 &&
2724 load_average > smtp_load_reserve &&
2726 verify_check_host(&smtp_reserve_hosts) != OK)
2728 log_write(L_connection_reject,
2729 LOG_MAIN, "temporarily refused connection from %s: not in "
2730 "reserve list and load average = %.2f", host_and_ident(FALSE),
2731 (double)load_average/1000.0);
2732 smtp_printf("421 %s: Too much load; please try again later\r\n",
2733 smtp_active_hostname);
2737 /* Determine whether unqualified senders or recipients are permitted
2738 for this host. Unfortunately, we have to do this every time, in order to
2739 set the flags so that they can be inspected when considering qualifying
2740 addresses in the headers. For a site that permits no qualification, this
2741 won't take long, however. */
2743 allow_unqualified_sender =
2744 verify_check_host(&sender_unqualified_hosts) == OK;
2746 allow_unqualified_recipient =
2747 verify_check_host(&recipient_unqualified_hosts) == OK;
2749 /* Determine whether HELO/EHLO is required for this host. The requirement
2750 can be hard or soft. */
2752 helo_required = verify_check_host(&helo_verify_hosts) == OK;
2754 helo_verify = verify_check_host(&helo_try_verify_hosts) == OK;
2756 /* Determine whether this hosts is permitted to send syntactic junk
2757 after a HELO or EHLO command. */
2759 helo_accept_junk = verify_check_host(&helo_accept_junk_hosts) == OK;
2762 /* For batch SMTP input we are now done. */
2764 if (smtp_batched_input) return TRUE;
2766 /* If valid Proxy Protocol source is connecting, set up session.
2767 * Failure will not allow any SMTP function other than QUIT. */
2769 #ifdef SUPPORT_PROXY
2770 proxy_session = FALSE;
2771 proxy_session_failed = FALSE;
2772 if (check_proxy_protocol_host())
2773 setup_proxy_protocol_host();
2776 /* Start up TLS if tls_on_connect is set. This is for supporting the legacy
2777 smtps port for use with older style SSL MTAs. */
2780 if (tls_in.on_connect && tls_server_start(tls_require_ciphers, &user_msg) != OK)
2781 return smtp_log_tls_fail(user_msg);
2784 /* Run the connect ACL if it exists */
2787 if (acl_smtp_connect)
2790 if ((rc = acl_check(ACL_WHERE_CONNECT, NULL, acl_smtp_connect, &user_msg,
2793 (void) smtp_handle_acl_fail(ACL_WHERE_CONNECT, rc, user_msg, log_msg);
2798 /* Output the initial message for a two-way SMTP connection. It may contain
2799 newlines, which then cause a multi-line response to be given. */
2801 code = US"220"; /* Default status code */
2802 esc = US""; /* Default extended status code */
2803 esclen = 0; /* Length of esc */
2807 if (!(s = expand_string(smtp_banner)))
2808 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "Expansion of \"%s\" (smtp_banner) "
2809 "failed: %s", smtp_banner, expand_string_message);
2815 smtp_message_code(&code, &codelen, &s, NULL, TRUE);
2819 esclen = codelen - 4;
2823 /* Remove any terminating newlines; might as well remove trailing space too */
2826 while (p > s && isspace(p[-1])) p--;
2829 /* It seems that CC:Mail is braindead, and assumes that the greeting message
2830 is all contained in a single IP packet. The original code wrote out the
2831 greeting using several calls to fprint/fputc, and on busy servers this could
2832 cause it to be split over more than one packet - which caused CC:Mail to fall
2833 over when it got the second part of the greeting after sending its first
2834 command. Sigh. To try to avoid this, build the complete greeting message
2835 first, and output it in one fell swoop. This gives a better chance of it
2836 ending up as a single packet. */
2838 ss = store_get(size);
2842 do /* At least once, in case we have an empty string */
2845 uschar *linebreak = Ustrchr(p, '\n');
2846 ss = string_catn(ss, &size, &ptr, code, 3);
2847 if (linebreak == NULL)
2850 ss = string_catn(ss, &size, &ptr, US" ", 1);
2854 len = linebreak - p;
2855 ss = string_catn(ss, &size, &ptr, US"-", 1);
2857 ss = string_catn(ss, &size, &ptr, esc, esclen);
2858 ss = string_catn(ss, &size, &ptr, p, len);
2859 ss = string_catn(ss, &size, &ptr, US"\r\n", 2);
2861 if (linebreak != NULL) p++;
2865 ss[ptr] = 0; /* string_cat leaves room for this */
2867 /* Before we write the banner, check that there is no input pending, unless
2868 this synchronisation check is disabled. */
2872 unsigned n = smtp_inend - smtp_inptr;
2875 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP protocol "
2876 "synchronization error (input sent without waiting for greeting): "
2877 "rejected connection from %s input=\"%s\"", host_and_ident(TRUE),
2878 string_printing(string_copyn(smtp_inptr, n)));
2879 smtp_printf("554 SMTP synchronization error\r\n");
2883 /* Now output the banner */
2885 smtp_printf("%s", ss);
2893 /*************************************************
2894 * Handle SMTP syntax and protocol errors *
2895 *************************************************/
2897 /* Write to the log for SMTP syntax errors in incoming commands, if configured
2898 to do so. Then transmit the error response. The return value depends on the
2899 number of syntax and protocol errors in this SMTP session.
2902 type error type, given as a log flag bit
2903 code response code; <= 0 means don't send a response
2904 data data to reflect in the response (can be NULL)
2905 errmess the error message
2907 Returns: -1 limit of syntax/protocol errors NOT exceeded
2908 +1 limit of syntax/protocol errors IS exceeded
2910 These values fit in with the values of the "done" variable in the main
2911 processing loop in smtp_setup_msg(). */
2914 synprot_error(int type, int code, uschar *data, uschar *errmess)
2918 log_write(type, LOG_MAIN, "SMTP %s error in \"%s\" %s %s",
2919 (type == L_smtp_syntax_error)? "syntax" : "protocol",
2920 string_printing(smtp_cmd_buffer), host_and_ident(TRUE), errmess);
2922 if (++synprot_error_count > smtp_max_synprot_errors)
2925 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
2926 "syntax or protocol errors (last command was \"%s\")",
2927 host_and_ident(FALSE), string_printing(smtp_cmd_buffer));
2932 smtp_printf("%d%c%s%s%s\r\n", code, (yield == 1)? '-' : ' ',
2933 (data == NULL)? US"" : data, (data == NULL)? US"" : US": ", errmess);
2935 smtp_printf("%d Too many syntax or protocol errors\r\n", code);
2944 /*************************************************
2945 * Send SMTP response, possibly multiline *
2946 *************************************************/
2948 /* There are, it seems, broken clients out there that cannot handle multiline
2949 responses. If no_multiline_responses is TRUE (it can be set from an ACL), we
2950 output nothing for non-final calls, and only the first line for anything else.
2953 code SMTP code, may involve extended status codes
2954 codelen length of smtp code; if > 4 there's an ESC
2955 final FALSE if the last line isn't the final line
2956 msg message text, possibly containing newlines
2962 smtp_respond(uschar* code, int codelen, BOOL final, uschar *msg)
2967 if (!final && no_multiline_responses) return;
2972 esclen = codelen - 4;
2975 /* If this is the first output for a (non-batch) RCPT command, see if all RCPTs
2976 have had the same. Note: this code is also present in smtp_printf(). It would
2977 be tidier to have it only in one place, but when it was added, it was easier to
2978 do it that way, so as not to have to mess with the code for the RCPT command,
2979 which sometimes uses smtp_printf() and sometimes smtp_respond(). */
2981 if (rcpt_in_progress)
2983 if (rcpt_smtp_response == NULL)
2984 rcpt_smtp_response = string_copy(msg);
2985 else if (rcpt_smtp_response_same &&
2986 Ustrcmp(rcpt_smtp_response, msg) != 0)
2987 rcpt_smtp_response_same = FALSE;
2988 rcpt_in_progress = FALSE;
2991 /* Not output the message, splitting it up into multiple lines if necessary. */
2995 uschar *nl = Ustrchr(msg, '\n');
2998 smtp_printf("%.3s%c%.*s%s\r\n", code, final? ' ':'-', esclen, esc, msg);
3001 else if (nl[1] == 0 || no_multiline_responses)
3003 smtp_printf("%.3s%c%.*s%.*s\r\n", code, final? ' ':'-', esclen, esc,
3004 (int)(nl - msg), msg);
3009 smtp_printf("%.3s-%.*s%.*s\r\n", code, esclen, esc, (int)(nl - msg), msg);
3011 while (isspace(*msg)) msg++;
3019 /*************************************************
3020 * Parse user SMTP message *
3021 *************************************************/
3023 /* This function allows for user messages overriding the response code details
3024 by providing a suitable response code string at the start of the message
3025 user_msg. Check the message for starting with a response code and optionally an
3026 extended status code. If found, check that the first digit is valid, and if so,
3027 change the code pointer and length to use the replacement. An invalid code
3028 causes a panic log; in this case, if the log messages is the same as the user
3029 message, we must also adjust the value of the log message to show the code that
3030 is actually going to be used (the original one).
3032 This function is global because it is called from receive.c as well as within
3035 Note that the code length returned includes the terminating whitespace
3036 character, which is always included in the regex match.
3039 code SMTP code, may involve extended status codes
3040 codelen length of smtp code; if > 4 there's an ESC
3042 log_msg optional log message, to be adjusted with the new SMTP code
3043 check_valid if true, verify the response code
3049 smtp_message_code(uschar **code, int *codelen, uschar **msg, uschar **log_msg,
3055 if (!msg || !*msg) return;
3057 if ((n = pcre_exec(regex_smtp_code, NULL, CS *msg, Ustrlen(*msg), 0,
3058 PCRE_EOPT, ovector, sizeof(ovector)/sizeof(int))) < 0) return;
3060 if (check_valid && (*msg)[0] != (*code)[0])
3062 log_write(0, LOG_MAIN|LOG_PANIC, "configured error code starts with "
3063 "incorrect digit (expected %c) in \"%s\"", (*code)[0], *msg);
3064 if (log_msg != NULL && *log_msg == *msg)
3065 *log_msg = string_sprintf("%s %s", *code, *log_msg + ovector[1]);
3070 *codelen = ovector[1]; /* Includes final space */
3072 *msg += ovector[1]; /* Chop the code off the message */
3079 /*************************************************
3080 * Handle an ACL failure *
3081 *************************************************/
3083 /* This function is called when acl_check() fails. As well as calls from within
3084 this module, it is called from receive.c for an ACL after DATA. It sorts out
3085 logging the incident, and sets up the error response. A message containing
3086 newlines is turned into a multiline SMTP response, but for logging, only the
3089 There's a table of default permanent failure response codes to use in
3090 globals.c, along with the table of names. VFRY is special. Despite RFC1123 it
3091 defaults disabled in Exim. However, discussion in connection with RFC 821bis
3092 (aka RFC 2821) has concluded that the response should be 252 in the disabled
3093 state, because there are broken clients that try VRFY before RCPT. A 5xx
3094 response should be given only when the address is positively known to be
3095 undeliverable. Sigh. We return 252 if there is no VRFY ACL or it provides
3096 no explicit code, but if there is one we let it know best.
3097 Also, for ETRN, 458 is given on refusal, and for AUTH, 503.
3099 From Exim 4.63, it is possible to override the response code details by
3100 providing a suitable response code string at the start of the message provided
3101 in user_msg. The code's first digit is checked for validity.
3104 where where the ACL was called from
3106 user_msg a message that can be included in an SMTP response
3107 log_msg a message for logging
3109 Returns: 0 in most cases
3110 2 if the failure code was FAIL_DROP, in which case the
3111 SMTP connection should be dropped (this value fits with the
3112 "done" variable in smtp_setup_msg() below)
3116 smtp_handle_acl_fail(int where, int rc, uschar *user_msg, uschar *log_msg)
3118 BOOL drop = rc == FAIL_DROP;
3122 uschar *sender_info = US"";
3124 #ifdef WITH_CONTENT_SCAN
3125 where == ACL_WHERE_MIME ? US"during MIME ACL checks" :
3127 where == ACL_WHERE_PREDATA ? US"DATA" :
3128 where == ACL_WHERE_DATA ? US"after DATA" :
3129 #ifndef DISABLE_PRDR
3130 where == ACL_WHERE_PRDR ? US"after DATA PRDR" :
3133 string_sprintf("%s %s", acl_wherenames[where], smtp_cmd_data) :
3134 string_sprintf("%s in \"connect\" ACL", acl_wherenames[where]);
3136 if (drop) rc = FAIL;
3138 /* Set the default SMTP code, and allow a user message to change it. */
3140 smtp_code = rc == FAIL ? acl_wherecodes[where] : US"451";
3141 smtp_message_code(&smtp_code, &codelen, &user_msg, &log_msg,
3142 where != ACL_WHERE_VRFY);
3144 /* We used to have sender_address here; however, there was a bug that was not
3145 updating sender_address after a rewrite during a verify. When this bug was
3146 fixed, sender_address at this point became the rewritten address. I'm not sure
3147 this is what should be logged, so I've changed to logging the unrewritten
3148 address to retain backward compatibility. */
3150 #ifndef WITH_CONTENT_SCAN
3151 if (where == ACL_WHERE_RCPT || where == ACL_WHERE_DATA)
3153 if (where == ACL_WHERE_RCPT || where == ACL_WHERE_DATA || where == ACL_WHERE_MIME)
3156 sender_info = string_sprintf("F=<%s>%s%s%s%s ",
3157 sender_address_unrewritten ? sender_address_unrewritten : sender_address,
3158 sender_host_authenticated ? US" A=" : US"",
3159 sender_host_authenticated ? sender_host_authenticated : US"",
3160 sender_host_authenticated && authenticated_id ? US":" : US"",
3161 sender_host_authenticated && authenticated_id ? authenticated_id : US""
3165 /* If there's been a sender verification failure with a specific message, and
3166 we have not sent a response about it yet, do so now, as a preliminary line for
3167 failures, but not defers. However, always log it for defer, and log it for fail
3168 unless the sender_verify_fail log selector has been turned off. */
3170 if (sender_verified_failed &&
3171 !testflag(sender_verified_failed, af_sverify_told))
3173 BOOL save_rcpt_in_progress = rcpt_in_progress;
3174 rcpt_in_progress = FALSE; /* So as not to treat these as the error */
3176 setflag(sender_verified_failed, af_sverify_told);
3178 if (rc != FAIL || LOGGING(sender_verify_fail))
3179 log_write(0, LOG_MAIN|LOG_REJECT, "%s sender verify %s for <%s>%s",
3180 host_and_ident(TRUE),
3181 ((sender_verified_failed->special_action & 255) == DEFER)? "defer":"fail",
3182 sender_verified_failed->address,
3183 (sender_verified_failed->message == NULL)? US"" :
3184 string_sprintf(": %s", sender_verified_failed->message));
3186 if (rc == FAIL && sender_verified_failed->user_message)
3187 smtp_respond(smtp_code, codelen, FALSE, string_sprintf(
3188 testflag(sender_verified_failed, af_verify_pmfail)?
3189 "Postmaster verification failed while checking <%s>\n%s\n"
3190 "Several RFCs state that you are required to have a postmaster\n"
3191 "mailbox for each mail domain. This host does not accept mail\n"
3192 "from domains whose servers reject the postmaster address."
3194 testflag(sender_verified_failed, af_verify_nsfail)?
3195 "Callback setup failed while verifying <%s>\n%s\n"
3196 "The initial connection, or a HELO or MAIL FROM:<> command was\n"
3197 "rejected. Refusing MAIL FROM:<> does not help fight spam, disregards\n"
3198 "RFC requirements, and stops you from receiving standard bounce\n"
3199 "messages. This host does not accept mail from domains whose servers\n"
3202 "Verification failed for <%s>\n%s",
3203 sender_verified_failed->address,
3204 sender_verified_failed->user_message));
3206 rcpt_in_progress = save_rcpt_in_progress;
3209 /* Sort out text for logging */
3211 log_msg = log_msg ? string_sprintf(": %s", log_msg) : US"";
3212 if ((lognl = Ustrchr(log_msg, '\n'))) *lognl = 0;
3214 /* Send permanent failure response to the command, but the code used isn't
3215 always a 5xx one - see comments at the start of this function. If the original
3216 rc was FAIL_DROP we drop the connection and yield 2. */
3219 smtp_respond(smtp_code, codelen, TRUE,
3220 user_msg ? user_msg : US"Administrative prohibition");
3222 /* Send temporary failure response to the command. Don't give any details,
3223 unless acl_temp_details is set. This is TRUE for a callout defer, a "defer"
3224 verb, and for a header verify when smtp_return_error_details is set.
3226 This conditional logic is all somewhat of a mess because of the odd
3227 interactions between temp_details and return_error_details. One day it should
3228 be re-implemented in a tidier fashion. */
3231 if (acl_temp_details && user_msg)
3233 if ( smtp_return_error_details
3234 && sender_verified_failed
3235 && sender_verified_failed->message
3237 smtp_respond(smtp_code, codelen, FALSE, sender_verified_failed->message);
3239 smtp_respond(smtp_code, codelen, TRUE, user_msg);
3242 smtp_respond(smtp_code, codelen, TRUE,
3243 US"Temporary local problem - please try later");
3245 /* Log the incident to the logs that are specified by log_reject_target
3246 (default main, reject). This can be empty to suppress logging of rejections. If
3247 the connection is not forcibly to be dropped, return 0. Otherwise, log why it
3248 is closing if required and return 2. */
3250 if (log_reject_target != 0)
3253 uschar * tls = s_tlslog(NULL, NULL, NULL);
3254 if (!tls) tls = US"";
3256 uschar * tls = US"";
3258 log_write(where == ACL_WHERE_CONNECT ? L_connection_reject : 0,
3259 log_reject_target, "%s%s%s %s%srejected %s%s",
3260 LOGGING(dnssec) && sender_host_dnssec ? US" DS" : US"",
3261 host_and_ident(TRUE),
3264 rc == FAIL ? US"" : US"temporarily ",
3268 if (!drop) return 0;
3270 log_write(L_smtp_connection, LOG_MAIN, "%s closed by DROP in ACL",
3271 smtp_get_connection_info());
3273 /* Run the not-quit ACL, but without any custom messages. This should not be a
3274 problem, because we get here only if some other ACL has issued "drop", and
3275 in that case, *its* custom messages will have been used above. */
3277 smtp_notquit_exit(US"acl-drop", NULL, NULL);
3284 /*************************************************
3285 * Handle SMTP exit when QUIT is not given *
3286 *************************************************/
3288 /* This function provides a logging/statistics hook for when an SMTP connection
3289 is dropped on the floor or the other end goes away. It's a global function
3290 because it's called from receive.c as well as this module. As well as running
3291 the NOTQUIT ACL, if there is one, this function also outputs a final SMTP
3292 response, either with a custom message from the ACL, or using a default. There
3293 is one case, however, when no message is output - after "drop". In that case,
3294 the ACL that obeyed "drop" has already supplied the custom message, and NULL is
3295 passed to this function.
3297 In case things go wrong while processing this function, causing an error that
3298 may re-enter this function, there is a recursion check.
3301 reason What $smtp_notquit_reason will be set to in the ACL;
3302 if NULL, the ACL is not run
3303 code The error code to return as part of the response
3304 defaultrespond The default message if there's no user_msg
3310 smtp_notquit_exit(uschar *reason, uschar *code, uschar *defaultrespond, ...)
3313 uschar *user_msg = NULL;
3314 uschar *log_msg = NULL;
3316 /* Check for recursive acll */
3318 if (smtp_exit_function_called)
3320 log_write(0, LOG_PANIC, "smtp_notquit_exit() called more than once (%s)",
3324 smtp_exit_function_called = TRUE;
3326 /* Call the not-QUIT ACL, if there is one, unless no reason is given. */
3328 if (acl_smtp_notquit && reason)
3330 smtp_notquit_reason = reason;
3331 if ((rc = acl_check(ACL_WHERE_NOTQUIT, NULL, acl_smtp_notquit, &user_msg,
3332 &log_msg)) == ERROR)
3333 log_write(0, LOG_MAIN|LOG_PANIC, "ACL for not-QUIT returned ERROR: %s",
3337 /* Write an SMTP response if we are expected to give one. As the default
3338 responses are all internal, they should always fit in the buffer, but code a
3339 warning, just in case. Note that string_vformat() still leaves a complete
3340 string, even if it is incomplete. */
3342 if (code && defaultrespond)
3345 smtp_respond(code, 3, TRUE, user_msg);
3350 va_start(ap, defaultrespond);
3351 if (!string_vformat(buffer, sizeof(buffer), CS defaultrespond, ap))
3352 log_write(0, LOG_MAIN|LOG_PANIC, "string too large in smtp_notquit_exit()");
3353 smtp_printf("%s %s\r\n", code, buffer);
3363 /*************************************************
3364 * Verify HELO argument *
3365 *************************************************/
3367 /* This function is called if helo_verify_hosts or helo_try_verify_hosts is
3368 matched. It is also called from ACL processing if verify = helo is used and
3369 verification was not previously tried (i.e. helo_try_verify_hosts was not
3370 matched). The result of its processing is to set helo_verified and
3371 helo_verify_failed. These variables should both be FALSE for this function to
3374 Note that EHLO/HELO is legitimately allowed to quote an address literal. Allow
3375 for IPv6 ::ffff: literals.
3378 Returns: TRUE if testing was completed;
3379 FALSE on a temporary failure
3383 smtp_verify_helo(void)
3387 HDEBUG(D_receive) debug_printf("verifying EHLO/HELO argument \"%s\"\n",
3390 if (sender_helo_name == NULL)
3392 HDEBUG(D_receive) debug_printf("no EHLO/HELO command was issued\n");
3395 /* Deal with the case of -bs without an IP address */
3397 else if (sender_host_address == NULL)
3399 HDEBUG(D_receive) debug_printf("no client IP address: assume success\n");
3400 helo_verified = TRUE;
3403 /* Deal with the more common case when there is a sending IP address */
3405 else if (sender_helo_name[0] == '[')
3407 helo_verified = Ustrncmp(sender_helo_name+1, sender_host_address,
3408 Ustrlen(sender_host_address)) == 0;
3413 if (strncmpic(sender_host_address, US"::ffff:", 7) == 0)
3414 helo_verified = Ustrncmp(sender_helo_name + 1,
3415 sender_host_address + 7, Ustrlen(sender_host_address) - 7) == 0;
3420 { if (helo_verified) debug_printf("matched host address\n"); }
3423 /* Do a reverse lookup if one hasn't already given a positive or negative
3424 response. If that fails, or the name doesn't match, try checking with a forward
3429 if (sender_host_name == NULL && !host_lookup_failed)
3430 yield = host_name_lookup() != DEFER;
3432 /* If a host name is known, check it and all its aliases. */
3434 if (sender_host_name)
3435 if ((helo_verified = strcmpic(sender_host_name, sender_helo_name) == 0))
3437 sender_helo_dnssec = sender_host_dnssec;
3438 HDEBUG(D_receive) debug_printf("matched host name\n");
3442 uschar **aliases = sender_host_aliases;
3444 if ((helo_verified = strcmpic(*aliases++, sender_helo_name) == 0))
3446 sender_helo_dnssec = sender_host_dnssec;
3450 HDEBUG(D_receive) if (helo_verified)
3451 debug_printf("matched alias %s\n", *(--aliases));
3454 /* Final attempt: try a forward lookup of the helo name */
3463 h.name = sender_helo_name;
3470 HDEBUG(D_receive) debug_printf("getting IP address for %s\n",
3472 rc = host_find_bydns(&h, NULL, HOST_FIND_BY_A,
3473 NULL, NULL, NULL, &d, NULL, NULL);
3474 if (rc == HOST_FOUND || rc == HOST_FOUND_LOCAL)
3475 for (hh = &h; hh; hh = hh->next)
3476 if (Ustrcmp(hh->address, sender_host_address) == 0)
3478 helo_verified = TRUE;
3479 if (h.dnssec == DS_YES) sender_helo_dnssec = TRUE;
3482 debug_printf("IP address for %s matches calling address\n"
3483 "Forward DNS security status: %sverified\n",
3484 sender_helo_name, sender_helo_dnssec ? "" : "un");
3491 if (!helo_verified) helo_verify_failed = TRUE; /* We've tried ... */
3498 /*************************************************
3499 * Send user response message *
3500 *************************************************/
3502 /* This function is passed a default response code and a user message. It calls
3503 smtp_message_code() to check and possibly modify the response code, and then
3504 calls smtp_respond() to transmit the response. I put this into a function
3505 just to avoid a lot of repetition.
3508 code the response code
3509 user_msg the user message
3515 smtp_user_msg(uschar *code, uschar *user_msg)
3518 smtp_message_code(&code, &len, &user_msg, NULL, TRUE);
3519 smtp_respond(code, len, TRUE, user_msg);
3525 smtp_in_auth(auth_instance *au, uschar ** s, uschar ** ss)
3527 const uschar *set_id = NULL;
3530 /* Run the checking code, passing the remainder of the command line as
3531 data. Initials the $auth<n> variables as empty. Initialize $0 empty and set
3532 it as the only set numerical variable. The authenticator may set $auth<n>
3533 and also set other numeric variables. The $auth<n> variables are preferred
3534 nowadays; the numerical variables remain for backwards compatibility.
3536 Afterwards, have a go at expanding the set_id string, even if
3537 authentication failed - for bad passwords it can be useful to log the
3538 userid. On success, require set_id to expand and exist, and put it in
3539 authenticated_id. Save this in permanent store, as the working store gets
3540 reset at HELO, RSET, etc. */
3542 for (i = 0; i < AUTH_VARS; i++) auth_vars[i] = NULL;
3544 expand_nlength[0] = 0; /* $0 contains nothing */
3546 rc = (au->info->servercode)(au, smtp_cmd_data);
3547 if (au->set_id) set_id = expand_string(au->set_id);
3548 expand_nmax = -1; /* Reset numeric variables */
3549 for (i = 0; i < AUTH_VARS; i++) auth_vars[i] = NULL; /* Reset $auth<n> */
3551 /* The value of authenticated_id is stored in the spool file and printed in
3552 log lines. It must not contain binary zeros or newline characters. In
3553 normal use, it never will, but when playing around or testing, this error
3554 can (did) happen. To guard against this, ensure that the id contains only
3555 printing characters. */
3557 if (set_id) set_id = string_printing(set_id);
3559 /* For the non-OK cases, set up additional logging data if set_id
3563 set_id = set_id && *set_id
3564 ? string_sprintf(" (set_id=%s)", set_id) : US"";
3566 /* Switch on the result */
3571 if (!au->set_id || set_id) /* Complete success */
3573 if (set_id) authenticated_id = string_copy_malloc(set_id);
3574 sender_host_authenticated = au->name;
3575 authentication_failed = FALSE;
3576 authenticated_fail_id = NULL; /* Impossible to already be set? */
3579 (sender_host_address ? protocols : protocols_local)
3580 [pextend + pauthed + (tls_in.active >= 0 ? pcrpted:0)];
3581 *s = *ss = US"235 Authentication succeeded";
3582 authenticated_by = au;
3586 /* Authentication succeeded, but we failed to expand the set_id string.
3587 Treat this as a temporary error. */
3589 auth_defer_msg = expand_string_message;
3593 if (set_id) authenticated_fail_id = string_copy_malloc(set_id);
3594 *s = string_sprintf("435 Unable to authenticate at present%s",
3595 auth_defer_user_msg);
3596 *ss = string_sprintf("435 Unable to authenticate at present%s: %s",
3597 set_id, auth_defer_msg);
3601 *s = *ss = US"501 Invalid base64 data";
3605 *s = *ss = US"501 Authentication cancelled";
3609 *s = *ss = US"553 Initial data not expected";
3613 if (set_id) authenticated_fail_id = string_copy_malloc(set_id);
3614 *s = US"535 Incorrect authentication data";
3615 *ss = string_sprintf("535 Incorrect authentication data%s", set_id);
3619 if (set_id) authenticated_fail_id = string_copy_malloc(set_id);
3620 *s = US"435 Internal error";
3621 *ss = string_sprintf("435 Internal error%s: return %d from authentication "
3622 "check", set_id, rc);
3634 qualify_recipient(uschar ** recipient, uschar * smtp_cmd_data, uschar * tag)
3637 if (allow_unqualified_recipient || strcmpic(*recipient, US"postmaster") == 0)
3639 DEBUG(D_receive) debug_printf("unqualified address %s accepted\n",
3641 rd = Ustrlen(recipient) + 1;
3642 *recipient = rewrite_address_qualify(*recipient, TRUE);
3645 smtp_printf("501 %s: recipient address must contain a domain\r\n",
3647 log_write(L_smtp_syntax_error,
3648 LOG_MAIN|LOG_REJECT, "unqualified %s rejected: <%s> %s%s",
3649 tag, *recipient, host_and_ident(TRUE), host_lookup_msg);
3657 smtp_quit_handler(uschar ** user_msgp, uschar ** log_msgp)
3660 incomplete_transaction_log(US"QUIT");
3663 int rc = acl_check(ACL_WHERE_QUIT, NULL, acl_smtp_quit, user_msgp, log_msgp);
3665 log_write(0, LOG_MAIN|LOG_PANIC, "ACL for QUIT returned ERROR: %s",
3669 smtp_respond(US"221", 3, TRUE, *user_msgp);
3671 smtp_printf("221 %s closing connection\r\n", smtp_active_hostname);
3674 tls_close(TRUE, TRUE);
3677 log_write(L_smtp_connection, LOG_MAIN, "%s closed by QUIT",
3678 smtp_get_connection_info());
3683 smtp_rset_handler(void)
3686 incomplete_transaction_log(US"RSET");
3687 smtp_printf("250 Reset OK\r\n");
3688 cmd_list[CMD_LIST_RSET].is_mail_cmd = FALSE;
3693 /*************************************************
3694 * Initialize for SMTP incoming message *
3695 *************************************************/
3697 /* This function conducts the initial dialogue at the start of an incoming SMTP
3698 message, and builds a list of recipients. However, if the incoming message
3699 is part of a batch (-bS option) a separate function is called since it would
3700 be messy having tests splattered about all over this function. This function
3701 therefore handles the case where interaction is occurring. The input and output
3702 files are set up in smtp_in and smtp_out.
3704 The global recipients_list is set to point to a vector of recipient_item
3705 blocks, whose number is given by recipients_count. This is extended by the
3706 receive_add_recipient() function. The global variable sender_address is set to
3707 the sender's address. The yield is +1 if a message has been successfully
3708 started, 0 if a QUIT command was encountered or the connection was refused from
3709 the particular host, or -1 if the connection was lost.
3713 Returns: > 0 message successfully started (reached DATA)
3714 = 0 QUIT read or end of file reached or call refused
3719 smtp_setup_msg(void)
3722 BOOL toomany = FALSE;
3723 BOOL discarded = FALSE;
3724 BOOL last_was_rej_mail = FALSE;
3725 BOOL last_was_rcpt = FALSE;
3726 void *reset_point = store_get(0);
3728 DEBUG(D_receive) debug_printf("smtp_setup_msg entered\n");
3730 /* Reset for start of new message. We allow one RSET not to be counted as a
3731 nonmail command, for those MTAs that insist on sending it between every
3732 message. Ditto for EHLO/HELO and for STARTTLS, to allow for going in and out of
3733 TLS between messages (an Exim client may do this if it has messages queued up
3734 for the host). Note: we do NOT reset AUTH at this point. */
3736 smtp_reset(reset_point);
3737 message_ended = END_NOTSTARTED;
3739 chunking_state = chunking_offered ? CHUNKING_OFFERED : CHUNKING_NOT_OFFERED;
3741 cmd_list[CMD_LIST_RSET].is_mail_cmd = TRUE;
3742 cmd_list[CMD_LIST_HELO].is_mail_cmd = TRUE;
3743 cmd_list[CMD_LIST_EHLO].is_mail_cmd = TRUE;
3745 cmd_list[CMD_LIST_STARTTLS].is_mail_cmd = TRUE;
3746 cmd_list[CMD_LIST_TLS_AUTH].is_mail_cmd = TRUE;
3749 /* Set the local signal handler for SIGTERM - it tries to end off tidily */
3751 os_non_restarting_signal(SIGTERM, command_sigterm_handler);
3753 /* Batched SMTP is handled in a different function. */
3755 if (smtp_batched_input) return smtp_setup_batch_msg();
3757 /* Deal with SMTP commands. This loop is exited by setting done to a POSITIVE
3758 value. The values are 2 larger than the required yield of the function. */
3762 const uschar **argv;
3763 uschar *etrn_command;
3764 uschar *etrn_serialize_key;
3766 uschar *log_msg, *smtp_code;
3767 uschar *user_msg = NULL;
3768 uschar *recipient = NULL;
3769 uschar *hello = NULL;
3771 BOOL was_rej_mail = FALSE;
3772 BOOL was_rcpt = FALSE;
3773 void (*oldsignal)(int);
3775 int start, end, sender_domain, recipient_domain;
3779 uschar *orcpt = NULL;
3783 /* Check once per STARTTLS or SSL-on-connect for a TLS AUTH */
3784 if ( tls_in.active >= 0
3786 && tls_in.certificate_verified
3787 && cmd_list[CMD_LIST_TLS_AUTH].is_mail_cmd
3790 cmd_list[CMD_LIST_TLS_AUTH].is_mail_cmd = FALSE;
3792 && (rc = acl_check(ACL_WHERE_AUTH, NULL, acl_smtp_auth,
3793 &user_msg, &log_msg)) != OK
3796 done = smtp_handle_acl_fail(ACL_WHERE_AUTH, rc, user_msg, log_msg);
3800 for (au = auths; au; au = au->next)
3801 if (strcmpic(US"tls", au->driver_name) == 0)
3803 smtp_cmd_data = NULL;
3805 if (smtp_in_auth(au, &s, &ss) == OK)
3806 { DEBUG(D_auth) debug_printf("tls auth succeeded\n"); }
3808 { DEBUG(D_auth) debug_printf("tls auth not succeeded\n"); }
3815 if (smtp_in) /* Avoid pure-ACKs while in cmd pingpong phase */
3816 (void) setsockopt(fileno(smtp_in), IPPROTO_TCP, TCP_QUICKACK,
3817 US &off, sizeof(off));
3820 switch(smtp_read_command(TRUE, GETC_BUFFER_UNLIMITED))
3822 /* The AUTH command is not permitted to occur inside a transaction, and may
3823 occur successfully only once per connection. Actually, that isn't quite
3824 true. When TLS is started, all previous information about a connection must
3825 be discarded, so a new AUTH is permitted at that time.
3827 AUTH may only be used when it has been advertised. However, it seems that
3828 there are clients that send AUTH when it hasn't been advertised, some of
3829 them even doing this after HELO. And there are MTAs that accept this. Sigh.
3830 So there's a get-out that allows this to happen.
3832 AUTH is initially labelled as a "nonmail command" so that one occurrence
3833 doesn't get counted. We change the label here so that multiple failing
3834 AUTHS will eventually hit the nonmail threshold. */
3838 authentication_failed = TRUE;
3839 cmd_list[CMD_LIST_AUTH].is_mail_cmd = FALSE;
3841 if (!auth_advertised && !allow_auth_unadvertised)
3843 done = synprot_error(L_smtp_protocol_error, 503, NULL,
3844 US"AUTH command used when not advertised");
3847 if (sender_host_authenticated)
3849 done = synprot_error(L_smtp_protocol_error, 503, NULL,
3850 US"already authenticated");
3855 done = synprot_error(L_smtp_protocol_error, 503, NULL,
3856 US"not permitted in mail transaction");
3863 && (rc = acl_check(ACL_WHERE_AUTH, NULL, acl_smtp_auth,
3864 &user_msg, &log_msg)) != OK
3867 done = smtp_handle_acl_fail(ACL_WHERE_AUTH, rc, user_msg, log_msg);
3871 /* Find the name of the requested authentication mechanism. */
3874 while ((c = *smtp_cmd_data) != 0 && !isspace(c))
3876 if (!isalnum(c) && c != '-' && c != '_')
3878 done = synprot_error(L_smtp_syntax_error, 501, NULL,
3879 US"invalid character in authentication mechanism name");
3885 /* If not at the end of the line, we must be at white space. Terminate the
3886 name and move the pointer on to any data that may be present. */
3888 if (*smtp_cmd_data != 0)
3890 *smtp_cmd_data++ = 0;
3891 while (isspace(*smtp_cmd_data)) smtp_cmd_data++;
3894 /* Search for an authentication mechanism which is configured for use
3895 as a server and which has been advertised (unless, sigh, allow_auth_
3896 unadvertised is set). */
3898 for (au = auths; au; au = au->next)
3899 if (strcmpic(s, au->public_name) == 0 && au->server &&
3900 (au->advertised || allow_auth_unadvertised))
3905 c = smtp_in_auth(au, &s, &ss);
3907 smtp_printf("%s\r\n", s);
3909 log_write(0, LOG_MAIN|LOG_REJECT, "%s authenticator failed for %s: %s",
3910 au->name, host_and_ident(FALSE), ss);
3913 done = synprot_error(L_smtp_protocol_error, 504, NULL,
3914 string_sprintf("%s authentication mechanism not supported", s));
3916 break; /* AUTH_CMD */
3918 /* The HELO/EHLO commands are permitted to appear in the middle of a
3919 session as well as at the beginning. They have the effect of a reset in
3920 addition to their other functions. Their absence at the start cannot be
3921 taken to be an error.
3925 If the EHLO command is not acceptable to the SMTP server, 501, 500,
3926 or 502 failure replies MUST be returned as appropriate. The SMTP
3927 server MUST stay in the same state after transmitting these replies
3928 that it was in before the EHLO was received.
3930 Therefore, we do not do the reset until after checking the command for
3931 acceptability. This change was made for Exim release 4.11. Previously
3932 it did the reset first. */
3945 HELO_EHLO: /* Common code for HELO and EHLO */
3946 cmd_list[CMD_LIST_HELO].is_mail_cmd = FALSE;
3947 cmd_list[CMD_LIST_EHLO].is_mail_cmd = FALSE;
3949 /* Reject the HELO if its argument was invalid or non-existent. A
3950 successful check causes the argument to be saved in malloc store. */
3952 if (!check_helo(smtp_cmd_data))
3954 smtp_printf("501 Syntactically invalid %s argument(s)\r\n", hello);
3956 log_write(0, LOG_MAIN|LOG_REJECT, "rejected %s from %s: syntactically "
3957 "invalid argument(s): %s", hello, host_and_ident(FALSE),
3958 (*smtp_cmd_argument == 0)? US"(no argument given)" :
3959 string_printing(smtp_cmd_argument));
3961 if (++synprot_error_count > smtp_max_synprot_errors)
3963 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
3964 "syntax or protocol errors (last command was \"%s\")",
3965 host_and_ident(FALSE), string_printing(smtp_cmd_buffer));
3972 /* If sender_host_unknown is true, we have got here via the -bs interface,
3973 not called from inetd. Otherwise, we are running an IP connection and the
3974 host address will be set. If the helo name is the primary name of this
3975 host and we haven't done a reverse lookup, force one now. If helo_required
3976 is set, ensure that the HELO name matches the actual host. If helo_verify
3977 is set, do the same check, but softly. */
3979 if (!sender_host_unknown)
3981 BOOL old_helo_verified = helo_verified;
3982 uschar *p = smtp_cmd_data;
3984 while (*p != 0 && !isspace(*p)) { *p = tolower(*p); p++; }
3987 /* Force a reverse lookup if HELO quoted something in helo_lookup_domains
3988 because otherwise the log can be confusing. */
3990 if (sender_host_name == NULL &&
3991 (deliver_domain = sender_helo_name, /* set $domain */
3992 match_isinlist(sender_helo_name, CUSS &helo_lookup_domains, 0,
3993 &domainlist_anchor, NULL, MCL_DOMAIN, TRUE, NULL)) == OK)
3994 (void)host_name_lookup();
3996 /* Rebuild the fullhost info to include the HELO name (and the real name
3997 if it was looked up.) */
3999 host_build_sender_fullhost(); /* Rebuild */
4000 set_process_info("handling%s incoming connection from %s",
4001 (tls_in.active >= 0)? " TLS" : "", host_and_ident(FALSE));
4003 /* Verify if configured. This doesn't give much security, but it does
4004 make some people happy to be able to do it. If helo_required is set,
4005 (host matches helo_verify_hosts) failure forces rejection. If helo_verify
4006 is set (host matches helo_try_verify_hosts), it does not. This is perhaps
4007 now obsolescent, since the verification can now be requested selectively
4010 helo_verified = helo_verify_failed = sender_helo_dnssec = FALSE;
4011 if (helo_required || helo_verify)
4013 BOOL tempfail = !smtp_verify_helo();
4018 smtp_printf("%d %s argument does not match calling host\r\n",
4019 tempfail? 451 : 550, hello);
4020 log_write(0, LOG_MAIN|LOG_REJECT, "%srejected \"%s %s\" from %s",
4021 tempfail? "temporarily " : "",
4022 hello, sender_helo_name, host_and_ident(FALSE));
4023 helo_verified = old_helo_verified;
4024 break; /* End of HELO/EHLO processing */
4026 HDEBUG(D_all) debug_printf("%s verification failed but host is in "
4027 "helo_try_verify_hosts\n", hello);
4032 #ifdef EXPERIMENTAL_SPF
4033 /* set up SPF context */
4034 spf_init(sender_helo_name, sender_host_address);
4037 /* Apply an ACL check if one is defined; afterwards, recheck
4038 synchronization in case the client started sending in a delay. */
4041 if ((rc = acl_check(ACL_WHERE_HELO, NULL, acl_smtp_helo,
4042 &user_msg, &log_msg)) != OK)
4044 done = smtp_handle_acl_fail(ACL_WHERE_HELO, rc, user_msg, log_msg);
4045 sender_helo_name = NULL;
4046 host_build_sender_fullhost(); /* Rebuild */
4049 else if (!check_sync()) goto SYNC_FAILURE;
4051 /* Generate an OK reply. The default string includes the ident if present,
4052 and also the IP address if present. Reflecting back the ident is intended
4053 as a deterrent to mail forgers. For maximum efficiency, and also because
4054 some broken systems expect each response to be in a single packet, arrange
4055 that the entire reply is sent in one write(). */
4057 auth_advertised = FALSE;
4058 pipelining_advertised = FALSE;
4060 tls_advertised = FALSE;
4062 dsn_advertised = FALSE;
4064 smtputf8_advertised = FALSE;
4067 smtp_code = US"250 "; /* Default response code plus space*/
4070 s = string_sprintf("%.3s %s Hello %s%s%s",
4072 smtp_active_hostname,
4073 sender_ident ? sender_ident : US"",
4074 sender_ident ? US" at " : US"",
4075 sender_host_name ? sender_host_name : sender_helo_name);
4080 if (sender_host_address)
4082 s = string_catn(s, &size, &ptr, US" [", 2);
4083 s = string_cat (s, &size, &ptr, sender_host_address);
4084 s = string_catn(s, &size, &ptr, US"]", 1);
4088 /* A user-supplied EHLO greeting may not contain more than one line. Note
4089 that the code returned by smtp_message_code() includes the terminating
4090 whitespace character. */
4096 smtp_message_code(&smtp_code, &codelen, &user_msg, NULL, TRUE);
4097 s = string_sprintf("%.*s%s", codelen, smtp_code, user_msg);
4098 if ((ss = strpbrk(CS s, "\r\n")) != NULL)
4100 log_write(0, LOG_MAIN|LOG_PANIC, "EHLO/HELO response must not contain "
4101 "newlines: message truncated: %s", string_printing(s));
4108 s = string_catn(s, &size, &ptr, US"\r\n", 2);
4110 /* If we received EHLO, we must create a multiline response which includes
4111 the functions supported. */
4117 /* I'm not entirely happy with this, as an MTA is supposed to check
4118 that it has enough room to accept a message of maximum size before
4119 it sends this. However, there seems little point in not sending it.
4120 The actual size check happens later at MAIL FROM time. By postponing it
4121 till then, VRFY and EXPN can be used after EHLO when space is short. */
4123 if (thismessage_size_limit > 0)
4125 sprintf(CS big_buffer, "%.3s-SIZE %d\r\n", smtp_code,
4126 thismessage_size_limit);
4127 s = string_cat(s, &size, &ptr, big_buffer);
4131 s = string_catn(s, &size, &ptr, smtp_code, 3);
4132 s = string_catn(s, &size, &ptr, US"-SIZE\r\n", 7);
4135 /* Exim does not do protocol conversion or data conversion. It is 8-bit
4136 clean; if it has an 8-bit character in its hand, it just sends it. It
4137 cannot therefore specify 8BITMIME and remain consistent with the RFCs.
4138 However, some users want this option simply in order to stop MUAs
4139 mangling messages that contain top-bit-set characters. It is therefore
4140 provided as an option. */
4142 if (accept_8bitmime)
4144 s = string_catn(s, &size, &ptr, smtp_code, 3);
4145 s = string_catn(s, &size, &ptr, US"-8BITMIME\r\n", 11);
4148 /* Advertise DSN support if configured to do so. */
4149 if (verify_check_host(&dsn_advertise_hosts) != FAIL)
4151 s = string_catn(s, &size, &ptr, smtp_code, 3);
4152 s = string_catn(s, &size, &ptr, US"-DSN\r\n", 6);
4153 dsn_advertised = TRUE;
4156 /* Advertise ETRN/VRFY/EXPN if there's are ACL checking whether a host is
4157 permitted to issue them; a check is made when any host actually tries. */
4161 s = string_catn(s, &size, &ptr, smtp_code, 3);
4162 s = string_catn(s, &size, &ptr, US"-ETRN\r\n", 7);
4166 s = string_catn(s, &size, &ptr, smtp_code, 3);
4167 s = string_catn(s, &size, &ptr, US"-VRFY\r\n", 7);
4171 s = string_catn(s, &size, &ptr, smtp_code, 3);
4172 s = string_catn(s, &size, &ptr, US"-EXPN\r\n", 7);
4175 /* Exim is quite happy with pipelining, so let the other end know that
4176 it is safe to use it, unless advertising is disabled. */
4178 if (pipelining_enable &&
4179 verify_check_host(&pipelining_advertise_hosts) == OK)
4181 s = string_catn(s, &size, &ptr, smtp_code, 3);
4182 s = string_catn(s, &size, &ptr, US"-PIPELINING\r\n", 13);
4183 sync_cmd_limit = NON_SYNC_CMD_PIPELINING;
4184 pipelining_advertised = TRUE;
4188 /* If any server authentication mechanisms are configured, advertise
4189 them if the current host is in auth_advertise_hosts. The problem with
4190 advertising always is that some clients then require users to
4191 authenticate (and aren't configurable otherwise) even though it may not
4192 be necessary (e.g. if the host is in host_accept_relay).
4194 RFC 2222 states that SASL mechanism names contain only upper case
4195 letters, so output the names in upper case, though we actually recognize
4196 them in either case in the AUTH command. */
4200 && !sender_host_authenticated
4202 && verify_check_host(&auth_advertise_hosts) == OK
4207 for (au = auths; au; au = au->next)
4208 if (au->server && (au->advertise_condition == NULL ||
4209 expand_check_condition(au->advertise_condition, au->name,
4210 US"authenticator")))
4215 s = string_catn(s, &size, &ptr, smtp_code, 3);
4216 s = string_catn(s, &size, &ptr, US"-AUTH", 5);
4218 auth_advertised = TRUE;
4221 s = string_catn(s, &size, &ptr, US" ", 1);
4222 s = string_cat (s, &size, &ptr, au->public_name);
4223 while (++saveptr < ptr) s[saveptr] = toupper(s[saveptr]);
4224 au->advertised = TRUE;
4227 au->advertised = FALSE;
4229 if (!first) s = string_catn(s, &size, &ptr, US"\r\n", 2);
4232 /* RFC 3030 CHUNKING */
4234 if (verify_check_host(&chunking_advertise_hosts) != FAIL)
4236 s = string_catn(s, &size, &ptr, smtp_code, 3);
4237 s = string_catn(s, &size, &ptr, US"-CHUNKING\r\n", 11);
4238 chunking_offered = TRUE;
4239 chunking_state = CHUNKING_OFFERED;
4242 /* Advertise TLS (Transport Level Security) aka SSL (Secure Socket Layer)
4243 if it has been included in the binary, and the host matches
4244 tls_advertise_hosts. We must *not* advertise if we are already in a
4245 secure connection. */
4248 if (tls_in.active < 0 &&
4249 verify_check_host(&tls_advertise_hosts) != FAIL)
4251 s = string_catn(s, &size, &ptr, smtp_code, 3);
4252 s = string_catn(s, &size, &ptr, US"-STARTTLS\r\n", 11);
4253 tls_advertised = TRUE;
4257 #ifndef DISABLE_PRDR
4258 /* Per Recipient Data Response, draft by Eric A. Hall extending RFC */
4261 s = string_catn(s, &size, &ptr, smtp_code, 3);
4262 s = string_catn(s, &size, &ptr, US"-PRDR\r\n", 7);
4267 if ( accept_8bitmime
4268 && verify_check_host(&smtputf8_advertise_hosts) != FAIL)
4270 s = string_catn(s, &size, &ptr, smtp_code, 3);
4271 s = string_catn(s, &size, &ptr, US"-SMTPUTF8\r\n", 11);
4272 smtputf8_advertised = TRUE;
4276 /* Finish off the multiline reply with one that is always available. */
4278 s = string_catn(s, &size, &ptr, smtp_code, 3);
4279 s = string_catn(s, &size, &ptr, US" HELP\r\n", 7);
4282 /* Terminate the string (for debug), write it, and note that HELO/EHLO
4288 if (tls_in.active >= 0) (void)tls_write(TRUE, s, ptr); else
4292 int i = fwrite(s, 1, ptr, smtp_out); i = i; /* compiler quietening */
4297 while ((cr = Ustrchr(s, '\r')) != NULL) /* lose CRs */
4298 memmove(cr, cr + 1, (ptr--) - (cr - s));
4299 debug_printf("SMTP>> %s", s);
4303 /* Reset the protocol and the state, abandoning any previous message. */
4305 (sender_host_address ? protocols : protocols_local)
4307 ? pextend + (sender_host_authenticated ? pauthed : 0)
4309 + (tls_in.active >= 0 ? pcrpted : 0)
4311 cancel_cutthrough_connection(TRUE, US"sent EHLO response");
4312 smtp_reset(reset_point);
4314 break; /* HELO/EHLO */
4317 /* The MAIL command requires an address as an operand. All we do
4318 here is to parse it for syntactic correctness. The form "<>" is
4319 a special case which converts into an empty string. The start/end
4320 pointers in the original are not used further for this address, as
4321 it is the canonical extracted address which is all that is kept. */
4325 smtp_mailcmd_count++; /* Count for limit and ratelimit */
4326 was_rej_mail = TRUE; /* Reset if accepted */
4327 env_mail_type_t * mail_args; /* Sanity check & validate args */
4329 if (helo_required && !helo_seen)
4331 smtp_printf("503 HELO or EHLO required\r\n");
4332 log_write(0, LOG_MAIN|LOG_REJECT, "rejected MAIL from %s: no "
4333 "HELO/EHLO given", host_and_ident(FALSE));
4337 if (sender_address != NULL)
4339 done = synprot_error(L_smtp_protocol_error, 503, NULL,
4340 US"sender already given");
4344 if (smtp_cmd_data[0] == 0)
4346 done = synprot_error(L_smtp_protocol_error, 501, NULL,
4347 US"MAIL must have an address operand");
4351 /* Check to see if the limit for messages per connection would be
4352 exceeded by accepting further messages. */
4354 if (smtp_accept_max_per_connection > 0 &&
4355 smtp_mailcmd_count > smtp_accept_max_per_connection)
4357 smtp_printf("421 too many messages in this connection\r\n");
4358 log_write(0, LOG_MAIN|LOG_REJECT, "rejected MAIL command %s: too many "
4359 "messages in one connection", host_and_ident(TRUE));
4363 /* Reset for start of message - even if this is going to fail, we
4364 obviously need to throw away any previous data. */
4366 cancel_cutthrough_connection(TRUE, US"MAIL received");
4367 smtp_reset(reset_point);
4369 sender_data = recipient_data = NULL;
4371 /* Loop, checking for ESMTP additions to the MAIL FROM command. */
4375 uschar *name, *value, *end;
4376 unsigned long int size;
4377 BOOL arg_error = FALSE;
4379 if (!extract_option(&name, &value)) break;
4381 for (mail_args = env_mail_type_list;
4382 mail_args->value != ENV_MAIL_OPT_NULL;
4385 if (strcmpic(name, mail_args->name) == 0)
4387 if (mail_args->need_value && strcmpic(value, US"") == 0)
4390 switch(mail_args->value)
4392 /* Handle SIZE= by reading the value. We don't do the check till later,
4393 in order to be able to log the sender address on failure. */
4394 case ENV_MAIL_OPT_SIZE:
4395 if (((size = Ustrtoul(value, &end, 10)), *end == 0))
4397 if ((size == ULONG_MAX && errno == ERANGE) || size > INT_MAX)
4399 message_size = (int)size;
4405 /* If this session was initiated with EHLO and accept_8bitmime is set,
4406 Exim will have indicated that it supports the BODY=8BITMIME option. In
4407 fact, it does not support this according to the RFCs, in that it does not
4408 take any special action for forwarding messages containing 8-bit
4409 characters. That is why accept_8bitmime is not the default setting, but
4410 some sites want the action that is provided. We recognize both "8BITMIME"
4411 and "7BIT" as body types, but take no action. */
4412 case ENV_MAIL_OPT_BODY:
4413 if (accept_8bitmime) {
4414 if (strcmpic(value, US"8BITMIME") == 0)
4416 else if (strcmpic(value, US"7BIT") == 0)
4421 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4422 US"invalid data for BODY");
4425 DEBUG(D_receive) debug_printf("8BITMIME: %d\n", body_8bitmime);
4431 /* Handle the two DSN options, but only if configured to do so (which
4432 will have caused "DSN" to be given in the EHLO response). The code itself
4433 is included only if configured in at build time. */
4435 case ENV_MAIL_OPT_RET:
4438 /* Check if RET has already been set */
4441 synprot_error(L_smtp_syntax_error, 501, NULL,
4442 US"RET can be specified once only");
4445 dsn_ret = strcmpic(value, US"HDRS") == 0
4447 : strcmpic(value, US"FULL") == 0
4450 DEBUG(D_receive) debug_printf("DSN_RET: %d\n", dsn_ret);
4451 /* Check for invalid invalid value, and exit with error */
4454 synprot_error(L_smtp_syntax_error, 501, NULL,
4455 US"Value for RET is invalid");
4460 case ENV_MAIL_OPT_ENVID:
4463 /* Check if the dsn envid has been already set */
4464 if (dsn_envid != NULL)
4466 synprot_error(L_smtp_syntax_error, 501, NULL,
4467 US"ENVID can be specified once only");
4470 dsn_envid = string_copy(value);
4471 DEBUG(D_receive) debug_printf("DSN_ENVID: %s\n", dsn_envid);
4475 /* Handle the AUTH extension. If the value given is not "<>" and either
4476 the ACL says "yes" or there is no ACL but the sending host is
4477 authenticated, we set it up as the authenticated sender. However, if the
4478 authenticator set a condition to be tested, we ignore AUTH on MAIL unless
4479 the condition is met. The value of AUTH is an xtext, which means that +,
4480 = and cntrl chars are coded in hex; however "<>" is unaffected by this
4482 case ENV_MAIL_OPT_AUTH:
4483 if (Ustrcmp(value, "<>") != 0)
4488 if (auth_xtextdecode(value, &authenticated_sender) < 0)
4490 /* Put back terminator overrides for error message */
4493 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4494 US"invalid data for AUTH");
4497 if (acl_smtp_mailauth == NULL)
4499 ignore_msg = US"client not authenticated";
4500 rc = (sender_host_authenticated != NULL)? OK : FAIL;
4504 ignore_msg = US"rejected by ACL";
4505 rc = acl_check(ACL_WHERE_MAILAUTH, NULL, acl_smtp_mailauth,
4506 &user_msg, &log_msg);
4512 if (authenticated_by == NULL ||
4513 authenticated_by->mail_auth_condition == NULL ||
4514 expand_check_condition(authenticated_by->mail_auth_condition,
4515 authenticated_by->name, US"authenticator"))
4516 break; /* Accept the AUTH */
4518 ignore_msg = US"server_mail_auth_condition failed";
4519 if (authenticated_id != NULL)
4520 ignore_msg = string_sprintf("%s: authenticated ID=\"%s\"",
4521 ignore_msg, authenticated_id);
4526 authenticated_sender = NULL;
4527 log_write(0, LOG_MAIN, "ignoring AUTH=%s from %s (%s)",
4528 value, host_and_ident(TRUE), ignore_msg);
4531 /* Should only get DEFER or ERROR here. Put back terminator
4532 overrides for error message */
4537 (void)smtp_handle_acl_fail(ACL_WHERE_MAILAUTH, rc, user_msg,
4544 #ifndef DISABLE_PRDR
4545 case ENV_MAIL_OPT_PRDR:
4547 prdr_requested = TRUE;
4552 case ENV_MAIL_OPT_UTF8:
4553 if (smtputf8_advertised)
4555 int old_pool = store_pool;
4557 DEBUG(D_receive) debug_printf("smtputf8 requested\n");
4558 message_smtputf8 = allow_utf8_domains = TRUE;
4559 store_pool = POOL_PERM;
4560 received_protocol = string_sprintf("utf8%s", received_protocol);
4561 store_pool = old_pool;
4565 /* No valid option. Stick back the terminator characters and break
4566 the loop. Do the name-terminator second as extract_option sets
4567 value==name when it found no equal-sign.
4568 An error for a malformed address will occur. */
4569 case ENV_MAIL_OPT_NULL:
4577 /* Break out of for loop if switch() had bad argument or
4578 when start of the email address is reached */
4579 if (arg_error) break;
4582 /* If we have passed the threshold for rate limiting, apply the current
4583 delay, and update it for next time, provided this is a limited host. */
4585 if (smtp_mailcmd_count > smtp_rlm_threshold &&
4586 verify_check_host(&smtp_ratelimit_hosts) == OK)
4588 DEBUG(D_receive) debug_printf("rate limit MAIL: delay %.3g sec\n",
4589 smtp_delay_mail/1000.0);
4590 millisleep((int)smtp_delay_mail);
4591 smtp_delay_mail *= smtp_rlm_factor;
4592 if (smtp_delay_mail > (double)smtp_rlm_limit)
4593 smtp_delay_mail = (double)smtp_rlm_limit;
4596 /* Now extract the address, first applying any SMTP-time rewriting. The
4597 TRUE flag allows "<>" as a sender address. */
4599 raw_sender = rewrite_existflags & rewrite_smtp
4600 ? rewrite_one(smtp_cmd_data, rewrite_smtp, NULL, FALSE, US"",
4601 global_rewrite_rules)
4605 parse_extract_address(raw_sender, &errmess, &start, &end, &sender_domain,
4610 done = synprot_error(L_smtp_syntax_error, 501, smtp_cmd_data, errmess);
4614 sender_address = raw_sender;
4616 /* If there is a configured size limit for mail, check that this message
4617 doesn't exceed it. The check is postponed to this point so that the sender
4620 if (thismessage_size_limit > 0 && message_size > thismessage_size_limit)
4622 smtp_printf("552 Message size exceeds maximum permitted\r\n");
4623 log_write(L_size_reject,
4624 LOG_MAIN|LOG_REJECT, "rejected MAIL FROM:<%s> %s: "
4625 "message too big: size%s=%d max=%d",
4627 host_and_ident(TRUE),
4628 (message_size == INT_MAX)? ">" : "",
4630 thismessage_size_limit);
4631 sender_address = NULL;
4635 /* Check there is enough space on the disk unless configured not to.
4636 When smtp_check_spool_space is set, the check is for thismessage_size_limit
4637 plus the current message - i.e. we accept the message only if it won't
4638 reduce the space below the threshold. Add 5000 to the size to allow for
4639 overheads such as the Received: line and storing of recipients, etc.
4640 By putting the check here, even when SIZE is not given, it allow VRFY
4641 and EXPN etc. to be used when space is short. */
4643 if (!receive_check_fs(
4644 (smtp_check_spool_space && message_size >= 0)?
4645 message_size + 5000 : 0))
4647 smtp_printf("452 Space shortage, please try later\r\n");
4648 sender_address = NULL;
4652 /* If sender_address is unqualified, reject it, unless this is a locally
4653 generated message, or the sending host or net is permitted to send
4654 unqualified addresses - typically local machines behaving as MUAs -
4655 in which case just qualify the address. The flag is set above at the start
4656 of the SMTP connection. */
4658 if (sender_domain == 0 && sender_address[0] != 0)
4660 if (allow_unqualified_sender)
4662 sender_domain = Ustrlen(sender_address) + 1;
4663 sender_address = rewrite_address_qualify(sender_address, FALSE);
4664 DEBUG(D_receive) debug_printf("unqualified address %s accepted\n",
4669 smtp_printf("501 %s: sender address must contain a domain\r\n",
4671 log_write(L_smtp_syntax_error,
4672 LOG_MAIN|LOG_REJECT,
4673 "unqualified sender rejected: <%s> %s%s",
4675 host_and_ident(TRUE),
4677 sender_address = NULL;
4682 /* Apply an ACL check if one is defined, before responding. Afterwards,
4683 when pipelining is not advertised, do another sync check in case the ACL
4684 delayed and the client started sending in the meantime. */
4688 rc = acl_check(ACL_WHERE_MAIL, NULL, acl_smtp_mail, &user_msg, &log_msg);
4689 if (rc == OK && !pipelining_advertised && !check_sync())
4695 if (rc == OK || rc == DISCARD)
4698 smtp_printf("%s%s%s", US"250 OK",
4699 #ifndef DISABLE_PRDR
4700 prdr_requested ? US", PRDR Requested" : US"",
4707 #ifndef DISABLE_PRDR
4709 user_msg = string_sprintf("%s%s", user_msg, US", PRDR Requested");
4711 smtp_user_msg(US"250", user_msg);
4713 smtp_delay_rcpt = smtp_rlr_base;
4714 recipients_discarded = (rc == DISCARD);
4715 was_rej_mail = FALSE;
4719 done = smtp_handle_acl_fail(ACL_WHERE_MAIL, rc, user_msg, log_msg);
4720 sender_address = NULL;
4725 /* The RCPT command requires an address as an operand. There may be any
4726 number of RCPT commands, specifying multiple recipients. We build them all
4727 into a data structure. The start/end values given by parse_extract_address
4728 are not used, as we keep only the extracted address. */
4733 was_rcpt = rcpt_in_progress = TRUE;
4735 /* There must be a sender address; if the sender was rejected and
4736 pipelining was advertised, we assume the client was pipelining, and do not
4737 count this as a protocol error. Reset was_rej_mail so that further RCPTs
4738 get the same treatment. */
4740 if (sender_address == NULL)
4742 if (pipelining_advertised && last_was_rej_mail)
4744 smtp_printf("503 sender not yet given\r\n");
4745 was_rej_mail = TRUE;
4749 done = synprot_error(L_smtp_protocol_error, 503, NULL,
4750 US"sender not yet given");
4751 was_rcpt = FALSE; /* Not a valid RCPT */
4757 /* Check for an operand */
4759 if (smtp_cmd_data[0] == 0)
4761 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4762 US"RCPT must have an address operand");
4767 /* Set the DSN flags orcpt and dsn_flags from the session*/
4773 uschar *name, *value;
4775 if (!extract_option(&name, &value))
4778 if (dsn_advertised && strcmpic(name, US"ORCPT") == 0)
4780 /* Check whether orcpt has been already set */
4783 synprot_error(L_smtp_syntax_error, 501, NULL,
4784 US"ORCPT can be specified once only");
4787 orcpt = string_copy(value);
4788 DEBUG(D_receive) debug_printf("DSN orcpt: %s\n", orcpt);
4791 else if (dsn_advertised && strcmpic(name, US"NOTIFY") == 0)
4793 /* Check if the notify flags have been already set */
4796 synprot_error(L_smtp_syntax_error, 501, NULL,
4797 US"NOTIFY can be specified once only");
4800 if (strcmpic(value, US"NEVER") == 0)
4801 flags |= rf_notify_never;
4808 while (*pp != 0 && *pp != ',') pp++;
4809 if (*pp == ',') *pp++ = 0;
4810 if (strcmpic(p, US"SUCCESS") == 0)
4812 DEBUG(D_receive) debug_printf("DSN: Setting notify success\n");
4813 flags |= rf_notify_success;
4815 else if (strcmpic(p, US"FAILURE") == 0)
4817 DEBUG(D_receive) debug_printf("DSN: Setting notify failure\n");
4818 flags |= rf_notify_failure;
4820 else if (strcmpic(p, US"DELAY") == 0)
4822 DEBUG(D_receive) debug_printf("DSN: Setting notify delay\n");
4823 flags |= rf_notify_delay;
4827 /* Catch any strange values */
4828 synprot_error(L_smtp_syntax_error, 501, NULL,
4829 US"Invalid value for NOTIFY parameter");
4834 DEBUG(D_receive) debug_printf("DSN Flags: %x\n", flags);
4838 /* Unknown option. Stick back the terminator characters and break
4839 the loop. An error for a malformed address will occur. */
4843 DEBUG(D_receive) debug_printf("Invalid RCPT option: %s : %s\n", name, value);
4850 /* Apply SMTP rewriting then extract the working address. Don't allow "<>"
4851 as a recipient address */
4853 recipient = rewrite_existflags & rewrite_smtp
4854 ? rewrite_one(smtp_cmd_data, rewrite_smtp, NULL, FALSE, US"",
4855 global_rewrite_rules)
4858 if (!(recipient = parse_extract_address(recipient, &errmess, &start, &end,
4859 &recipient_domain, FALSE)))
4861 done = synprot_error(L_smtp_syntax_error, 501, smtp_cmd_data, errmess);
4866 /* If the recipient address is unqualified, reject it, unless this is a
4867 locally generated message. However, unqualified addresses are permitted
4868 from a configured list of hosts and nets - typically when behaving as
4869 MUAs rather than MTAs. Sad that SMTP is used for both types of traffic,
4870 really. The flag is set at the start of the SMTP connection.
4872 RFC 1123 talks about supporting "the reserved mailbox postmaster"; I always
4873 assumed this meant "reserved local part", but the revision of RFC 821 and
4874 friends now makes it absolutely clear that it means *mailbox*. Consequently
4875 we must always qualify this address, regardless. */
4877 if (!recipient_domain)
4878 if (!(recipient_domain = qualify_recipient(&recipient, smtp_cmd_data,
4885 /* Check maximum allowed */
4887 if (rcpt_count > recipients_max && recipients_max > 0)
4889 if (recipients_max_reject)
4892 smtp_printf("552 too many recipients\r\n");
4894 log_write(0, LOG_MAIN|LOG_REJECT, "too many recipients: message "
4895 "rejected: sender=<%s> %s", sender_address, host_and_ident(TRUE));
4900 smtp_printf("452 too many recipients\r\n");
4902 log_write(0, LOG_MAIN|LOG_REJECT, "too many recipients: excess "
4903 "temporarily rejected: sender=<%s> %s", sender_address,
4904 host_and_ident(TRUE));
4911 /* If we have passed the threshold for rate limiting, apply the current
4912 delay, and update it for next time, provided this is a limited host. */
4914 if (rcpt_count > smtp_rlr_threshold &&
4915 verify_check_host(&smtp_ratelimit_hosts) == OK)
4917 DEBUG(D_receive) debug_printf("rate limit RCPT: delay %.3g sec\n",
4918 smtp_delay_rcpt/1000.0);
4919 millisleep((int)smtp_delay_rcpt);
4920 smtp_delay_rcpt *= smtp_rlr_factor;
4921 if (smtp_delay_rcpt > (double)smtp_rlr_limit)
4922 smtp_delay_rcpt = (double)smtp_rlr_limit;
4925 /* If the MAIL ACL discarded all the recipients, we bypass ACL checking
4926 for them. Otherwise, check the access control list for this recipient. As
4927 there may be a delay in this, re-check for a synchronization error
4928 afterwards, unless pipelining was advertised. */
4930 if (recipients_discarded)
4933 if ( (rc = acl_check(ACL_WHERE_RCPT, recipient, acl_smtp_rcpt, &user_msg,
4935 && !pipelining_advertised && !check_sync())
4938 /* The ACL was happy */
4943 smtp_user_msg(US"250", user_msg);
4945 smtp_printf("250 Accepted\r\n");
4946 receive_add_recipient(recipient, -1);
4948 /* Set the dsn flags in the recipients_list */
4949 recipients_list[recipients_count-1].orcpt = orcpt;
4950 recipients_list[recipients_count-1].dsn_flags = flags;
4952 DEBUG(D_receive) debug_printf("DSN: orcpt: %s flags: %d\n",
4953 recipients_list[recipients_count-1].orcpt,
4954 recipients_list[recipients_count-1].dsn_flags);
4957 /* The recipient was discarded */
4959 else if (rc == DISCARD)
4962 smtp_user_msg(US"250", user_msg);
4964 smtp_printf("250 Accepted\r\n");
4967 log_write(0, LOG_MAIN|LOG_REJECT, "%s F=<%s> RCPT %s: "
4968 "discarded by %s ACL%s%s", host_and_ident(TRUE),
4969 sender_address_unrewritten? sender_address_unrewritten : sender_address,
4970 smtp_cmd_argument, recipients_discarded? "MAIL" : "RCPT",
4971 log_msg ? US": " : US"", log_msg ? log_msg : US"");
4974 /* Either the ACL failed the address, or it was deferred. */
4978 if (rc == FAIL) rcpt_fail_count++; else rcpt_defer_count++;
4979 done = smtp_handle_acl_fail(ACL_WHERE_RCPT, rc, user_msg, log_msg);
4984 /* The DATA command is legal only if it follows successful MAIL FROM
4985 and RCPT TO commands. However, if pipelining is advertised, a bad DATA is
4986 not counted as a protocol error if it follows RCPT (which must have been
4987 rejected if there are no recipients.) This function is complete when a
4988 valid DATA command is encountered.
4990 Note concerning the code used: RFC 2821 says this:
4992 - If there was no MAIL, or no RCPT, command, or all such commands
4993 were rejected, the server MAY return a "command out of sequence"
4994 (503) or "no valid recipients" (554) reply in response to the
4997 The example in the pipelining RFC 2920 uses 554, but I use 503 here
4998 because it is the same whether pipelining is in use or not.
5000 If all the RCPT commands that precede DATA provoked the same error message
5001 (often indicating some kind of system error), it is helpful to include it
5002 with the DATA rejection (an idea suggested by Tony Finch). */
5009 if (chunking_state != CHUNKING_OFFERED)
5011 done = synprot_error(L_smtp_protocol_error, 503, NULL,
5012 US"BDAT command used when CHUNKING not advertised");
5016 /* grab size, endmarker */
5018 if (sscanf(CS smtp_cmd_data, "%u %n", &chunking_datasize, &n) < 1)
5020 done = synprot_error(L_smtp_protocol_error, 501, NULL,
5021 US"missing size for BDAT command");
5024 chunking_state = strcmpic(smtp_cmd_data+n, US"LAST") == 0
5025 ? CHUNKING_LAST : CHUNKING_ACTIVE;
5026 chunking_data_left = chunking_datasize;
5027 DEBUG(D_receive) debug_printf("chunking state %d, %d bytes\n",
5028 (int)chunking_state, chunking_data_left);
5030 lwr_receive_getc = receive_getc;
5031 lwr_receive_getbuf = receive_getbuf;
5032 lwr_receive_ungetc = receive_ungetc;
5033 receive_getc = bdat_getc;
5034 receive_ungetc = bdat_ungetc;
5042 DATA_BDAT: /* Common code for DATA and BDAT */
5043 if (!discarded && recipients_count <= 0)
5045 if (rcpt_smtp_response_same && rcpt_smtp_response != NULL)
5047 uschar *code = US"503";
5048 int len = Ustrlen(rcpt_smtp_response);
5049 smtp_respond(code, 3, FALSE, US"All RCPT commands were rejected with "
5051 /* Responses from smtp_printf() will have \r\n on the end */
5052 if (len > 2 && rcpt_smtp_response[len-2] == '\r')
5053 rcpt_smtp_response[len-2] = 0;
5054 smtp_respond(code, 3, FALSE, rcpt_smtp_response);
5056 if (pipelining_advertised && last_was_rcpt)
5057 smtp_printf("503 Valid RCPT command must precede %s\r\n",
5058 smtp_names[smtp_connection_had[smtp_ch_index-1]]);
5060 done = synprot_error(L_smtp_protocol_error, 503, NULL,
5061 smtp_connection_had[smtp_ch_index-1] == SCH_DATA
5062 ? US"valid RCPT command must precede DATA"
5063 : US"valid RCPT command must precede BDAT");
5065 if (chunking_state > CHUNKING_OFFERED)
5070 if (toomany && recipients_max_reject)
5072 sender_address = NULL; /* This will allow a new MAIL without RSET */
5073 sender_address_unrewritten = NULL;
5074 smtp_printf("554 Too many recipients\r\n");
5078 if (chunking_state > CHUNKING_OFFERED)
5079 rc = OK; /* No predata ACL or go-ahead output for BDAT */
5082 /* If there is an ACL, re-check the synchronization afterwards, since the
5083 ACL may have delayed. To handle cutthrough delivery enforce a dummy call
5084 to get the DATA command sent. */
5086 if (acl_smtp_predata == NULL && cutthrough.fd < 0)
5090 uschar * acl = acl_smtp_predata ? acl_smtp_predata : US"accept";
5091 enable_dollar_recipients = TRUE;
5092 rc = acl_check(ACL_WHERE_PREDATA, NULL, acl, &user_msg,
5094 enable_dollar_recipients = FALSE;
5095 if (rc == OK && !check_sync())
5099 { /* Either the ACL failed the address, or it was deferred. */
5100 done = smtp_handle_acl_fail(ACL_WHERE_PREDATA, rc, user_msg, log_msg);
5106 smtp_user_msg(US"354", user_msg);
5109 "354 Enter message, ending with \".\" on a line by itself\r\n");
5113 if (smtp_in) /* all ACKs needed to ramp window up for bulk data */
5114 (void) setsockopt(fileno(smtp_in), IPPROTO_TCP, TCP_QUICKACK,
5115 US &on, sizeof(on));
5118 message_ended = END_NOTENDED; /* Indicate in middle of data */
5129 if (!(address = parse_extract_address(smtp_cmd_data, &errmess,
5130 &start, &end, &recipient_domain, FALSE)))
5132 smtp_printf("501 %s\r\n", errmess);
5136 if (!recipient_domain)
5137 if (!(recipient_domain = qualify_recipient(&address, smtp_cmd_data,
5141 if ((rc = acl_check(ACL_WHERE_VRFY, address, acl_smtp_vrfy,
5142 &user_msg, &log_msg)) != OK)
5143 done = smtp_handle_acl_fail(ACL_WHERE_VRFY, rc, user_msg, log_msg);
5147 address_item * addr = deliver_make_addr(address, FALSE);
5149 switch(verify_address(addr, NULL, vopt_is_recipient | vopt_qualify, -1,
5150 -1, -1, NULL, NULL, NULL))
5153 s = string_sprintf("250 <%s> is deliverable", address);
5157 s = (addr->user_message != NULL)?
5158 string_sprintf("451 <%s> %s", address, addr->user_message) :
5159 string_sprintf("451 Cannot resolve <%s> at this time", address);
5163 s = (addr->user_message != NULL)?
5164 string_sprintf("550 <%s> %s", address, addr->user_message) :
5165 string_sprintf("550 <%s> is not deliverable", address);
5166 log_write(0, LOG_MAIN, "VRFY failed for %s %s",
5167 smtp_cmd_argument, host_and_ident(TRUE));
5171 smtp_printf("%s\r\n", s);
5179 rc = acl_check(ACL_WHERE_EXPN, NULL, acl_smtp_expn, &user_msg, &log_msg);
5181 done = smtp_handle_acl_fail(ACL_WHERE_EXPN, rc, user_msg, log_msg);
5184 BOOL save_log_testing_mode = log_testing_mode;
5185 address_test_mode = log_testing_mode = TRUE;
5186 (void) verify_address(deliver_make_addr(smtp_cmd_data, FALSE),
5187 smtp_out, vopt_is_recipient | vopt_qualify | vopt_expn, -1, -1, -1,
5189 address_test_mode = FALSE;
5190 log_testing_mode = save_log_testing_mode; /* true for -bh */
5199 if (!tls_advertised)
5201 done = synprot_error(L_smtp_protocol_error, 503, NULL,
5202 US"STARTTLS command used when not advertised");
5206 /* Apply an ACL check if one is defined */
5208 if ( acl_smtp_starttls
5209 && (rc = acl_check(ACL_WHERE_STARTTLS, NULL, acl_smtp_starttls,
5210 &user_msg, &log_msg)) != OK
5213 done = smtp_handle_acl_fail(ACL_WHERE_STARTTLS, rc, user_msg, log_msg);
5217 /* RFC 2487 is not clear on when this command may be sent, though it
5218 does state that all information previously obtained from the client
5219 must be discarded if a TLS session is started. It seems reasonable to
5220 do an implied RSET when STARTTLS is received. */
5222 incomplete_transaction_log(US"STARTTLS");
5223 cancel_cutthrough_connection(TRUE, US"STARTTLS received");
5224 smtp_reset(reset_point);
5226 cmd_list[CMD_LIST_STARTTLS].is_mail_cmd = FALSE;
5228 /* There's an attack where more data is read in past the STARTTLS command
5229 before TLS is negotiated, then assumed to be part of the secure session
5230 when used afterwards; we use segregated input buffers, so are not
5231 vulnerable, but we want to note when it happens and, for sheer paranoia,
5232 ensure that the buffer is "wiped".
5233 Pipelining sync checks will normally have protected us too, unless disabled
5234 by configuration. */
5236 if (receive_smtp_buffered())
5239 debug_printf("Non-empty input buffer after STARTTLS; naive attack?\n");
5240 if (tls_in.active < 0)
5241 smtp_inend = smtp_inptr = smtp_inbuffer;
5242 /* and if TLS is already active, tls_server_start() should fail */
5245 /* There is nothing we value in the input buffer and if TLS is successfully
5246 negotiated, we won't use this buffer again; if TLS fails, we'll just read
5247 fresh content into it. The buffer contains arbitrary content from an
5248 untrusted remote source; eg: NOOP <shellcode>\r\nSTARTTLS\r\n
5249 It seems safest to just wipe away the content rather than leave it as a
5250 target to jump to. */
5252 memset(smtp_inbuffer, 0, IN_BUFFER_SIZE);
5254 /* Attempt to start up a TLS session, and if successful, discard all
5255 knowledge that was obtained previously. At least, that's what the RFC says,
5256 and that's what happens by default. However, in order to work round YAEB,
5257 there is an option to remember the esmtp state. Sigh.
5259 We must allow for an extra EHLO command and an extra AUTH command after
5260 STARTTLS that don't add to the nonmail command count. */
5263 if ((rc = tls_server_start(tls_require_ciphers, &s)) == OK)
5265 if (!tls_remember_esmtp)
5266 helo_seen = esmtp = auth_advertised = pipelining_advertised = FALSE;
5267 cmd_list[CMD_LIST_EHLO].is_mail_cmd = TRUE;
5268 cmd_list[CMD_LIST_AUTH].is_mail_cmd = TRUE;
5269 cmd_list[CMD_LIST_TLS_AUTH].is_mail_cmd = TRUE;
5270 if (sender_helo_name != NULL)
5272 store_free(sender_helo_name);
5273 sender_helo_name = NULL;
5274 host_build_sender_fullhost(); /* Rebuild */
5275 set_process_info("handling incoming TLS connection from %s",
5276 host_and_ident(FALSE));
5279 (sender_host_address ? protocols : protocols_local)
5281 ? pextend + (sender_host_authenticated ? pauthed : 0)
5283 + (tls_in.active >= 0 ? pcrpted : 0)
5286 sender_host_authenticated = NULL;
5287 authenticated_id = NULL;
5288 sync_cmd_limit = NON_SYNC_CMD_NON_PIPELINING;
5289 DEBUG(D_tls) debug_printf("TLS active\n");
5290 break; /* Successful STARTTLS */
5293 (void) smtp_log_tls_fail(s);
5295 /* Some local configuration problem was discovered before actually trying
5296 to do a TLS handshake; give a temporary error. */
5300 smtp_printf("454 TLS currently unavailable\r\n");
5304 /* Hard failure. Reject everything except QUIT or closed connection. One
5305 cause for failure is a nested STARTTLS, in which case tls_in.active remains
5306 set, but we must still reject all incoming commands. */
5308 DEBUG(D_tls) debug_printf("TLS failed to start\n");
5309 while (done <= 0) switch(smtp_read_command(FALSE, GETC_BUFFER_UNLIMITED))
5312 log_write(L_smtp_connection, LOG_MAIN, "%s closed by EOF",
5313 smtp_get_connection_info());
5314 smtp_notquit_exit(US"tls-failed", NULL, NULL);
5318 /* It is perhaps arguable as to which exit ACL should be called here,
5319 but as it is probably a situation that almost never arises, it
5320 probably doesn't matter. We choose to call the real QUIT ACL, which in
5321 some sense is perhaps "right". */
5326 && ((rc = acl_check(ACL_WHERE_QUIT, NULL, acl_smtp_quit, &user_msg,
5327 &log_msg)) == ERROR))
5328 log_write(0, LOG_MAIN|LOG_PANIC, "ACL for QUIT returned ERROR: %s",
5331 smtp_respond(US"221", 3, TRUE, user_msg);
5333 smtp_printf("221 %s closing connection\r\n", smtp_active_hostname);
5334 log_write(L_smtp_connection, LOG_MAIN, "%s closed by QUIT",
5335 smtp_get_connection_info());
5340 smtp_printf("554 Security failure\r\n");
5343 tls_close(TRUE, TRUE);
5348 /* The ACL for QUIT is provided for gathering statistical information or
5349 similar; it does not affect the response code, but it can supply a custom
5353 smtp_quit_handler(&user_msg, &log_msg);
5359 smtp_rset_handler();
5360 cancel_cutthrough_connection(TRUE, US"RSET received");
5361 smtp_reset(reset_point);
5368 smtp_printf("250 OK\r\n");
5372 /* Show ETRN/EXPN/VRFY if there's an ACL for checking hosts; if actually
5373 used, a check will be done for permitted hosts. Show STARTTLS only if not
5374 already in a TLS session and if it would be advertised in the EHLO
5379 smtp_printf("214-Commands supported:\r\n");
5383 Ustrcat(buffer, " AUTH");
5385 if (tls_in.active < 0 &&
5386 verify_check_host(&tls_advertise_hosts) != FAIL)
5387 Ustrcat(buffer, " STARTTLS");
5389 Ustrcat(buffer, " HELO EHLO MAIL RCPT DATA BDAT");
5390 Ustrcat(buffer, " NOOP QUIT RSET HELP");
5391 if (acl_smtp_etrn != NULL) Ustrcat(buffer, " ETRN");
5392 if (acl_smtp_expn != NULL) Ustrcat(buffer, " EXPN");
5393 if (acl_smtp_vrfy != NULL) Ustrcat(buffer, " VRFY");
5394 smtp_printf("214%s\r\n", buffer);
5400 incomplete_transaction_log(US"connection lost");
5401 smtp_notquit_exit(US"connection-lost", US"421",
5402 US"%s lost input connection", smtp_active_hostname);
5404 /* Don't log by default unless in the middle of a message, as some mailers
5405 just drop the call rather than sending QUIT, and it clutters up the logs.
5408 if (sender_address != NULL || recipients_count > 0)
5409 log_write(L_lost_incoming_connection,
5411 "unexpected %s while reading SMTP command from %s%s",
5412 sender_host_unknown? "EOF" : "disconnection",
5413 host_and_ident(FALSE), smtp_read_error);
5415 else log_write(L_smtp_connection, LOG_MAIN, "%s lost%s",
5416 smtp_get_connection_info(), smtp_read_error);
5424 if (sender_address != NULL)
5426 done = synprot_error(L_smtp_protocol_error, 503, NULL,
5427 US"ETRN is not permitted inside a transaction");
5431 log_write(L_etrn, LOG_MAIN, "ETRN %s received from %s", smtp_cmd_argument,
5432 host_and_ident(FALSE));
5434 if ((rc = acl_check(ACL_WHERE_ETRN, NULL, acl_smtp_etrn,
5435 &user_msg, &log_msg)) != OK)
5437 done = smtp_handle_acl_fail(ACL_WHERE_ETRN, rc, user_msg, log_msg);
5441 /* Compute the serialization key for this command. */
5443 etrn_serialize_key = string_sprintf("etrn-%s\n", smtp_cmd_data);
5445 /* If a command has been specified for running as a result of ETRN, we
5446 permit any argument to ETRN. If not, only the # standard form is permitted,
5447 since that is strictly the only kind of ETRN that can be implemented
5448 according to the RFC. */
5450 if (smtp_etrn_command != NULL)
5454 etrn_command = smtp_etrn_command;
5455 deliver_domain = smtp_cmd_data;
5456 rc = transport_set_up_command(&argv, smtp_etrn_command, TRUE, 0, NULL,
5457 US"ETRN processing", &error);
5458 deliver_domain = NULL;
5461 log_write(0, LOG_MAIN|LOG_PANIC, "failed to set up ETRN command: %s",
5463 smtp_printf("458 Internal failure\r\n");
5468 /* Else set up to call Exim with the -R option. */
5472 if (*smtp_cmd_data++ != '#')
5474 done = synprot_error(L_smtp_syntax_error, 501, NULL,
5475 US"argument must begin with #");
5478 etrn_command = US"exim -R";
5479 argv = CUSS child_exec_exim(CEE_RETURN_ARGV, TRUE, NULL, TRUE,
5480 *queue_name ? 4 : 2,
5481 US"-R", smtp_cmd_data,
5482 US"-MCG", queue_name);
5485 /* If we are host-testing, don't actually do anything. */
5491 debug_printf("ETRN command is: %s\n", etrn_command);
5492 debug_printf("ETRN command execution skipped\n");
5494 if (user_msg == NULL) smtp_printf("250 OK\r\n");
5495 else smtp_user_msg(US"250", user_msg);
5500 /* If ETRN queue runs are to be serialized, check the database to
5501 ensure one isn't already running. */
5503 if (smtp_etrn_serialize && !enq_start(etrn_serialize_key, 1))
5505 smtp_printf("458 Already processing %s\r\n", smtp_cmd_data);
5509 /* Fork a child process and run the command. We don't want to have to
5510 wait for the process at any point, so set SIGCHLD to SIG_IGN before
5511 forking. It should be set that way anyway for external incoming SMTP,
5512 but we save and restore to be tidy. If serialization is required, we
5513 actually run the command in yet another process, so we can wait for it
5514 to complete and then remove the serialization lock. */
5516 oldsignal = signal(SIGCHLD, SIG_IGN);
5518 if ((pid = fork()) == 0)
5520 smtp_input = FALSE; /* This process is not associated with the */
5521 (void)fclose(smtp_in); /* SMTP call any more. */
5522 (void)fclose(smtp_out);
5524 signal(SIGCHLD, SIG_DFL); /* Want to catch child */
5526 /* If not serializing, do the exec right away. Otherwise, fork down
5527 into another process. */
5529 if (!smtp_etrn_serialize || (pid = fork()) == 0)
5531 DEBUG(D_exec) debug_print_argv(argv);
5532 exim_nullstd(); /* Ensure std{in,out,err} exist */
5533 execv(CS argv[0], (char *const *)argv);
5534 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "exec of \"%s\" (ETRN) failed: %s",
5535 etrn_command, strerror(errno));
5536 _exit(EXIT_FAILURE); /* paranoia */
5539 /* Obey this if smtp_serialize and the 2nd fork yielded non-zero. That
5540 is, we are in the first subprocess, after forking again. All we can do
5541 for a failing fork is to log it. Otherwise, wait for the 2nd process to
5542 complete, before removing the serialization. */
5545 log_write(0, LOG_MAIN|LOG_PANIC, "2nd fork for serialized ETRN "
5546 "failed: %s", strerror(errno));
5550 DEBUG(D_any) debug_printf("waiting for serialized ETRN process %d\n",
5552 (void)wait(&status);
5553 DEBUG(D_any) debug_printf("serialized ETRN process %d ended\n",
5557 enq_end(etrn_serialize_key);
5558 _exit(EXIT_SUCCESS);
5561 /* Back in the top level SMTP process. Check that we started a subprocess
5562 and restore the signal state. */
5566 log_write(0, LOG_MAIN|LOG_PANIC, "fork of process for ETRN failed: %s",
5568 smtp_printf("458 Unable to fork process\r\n");
5569 if (smtp_etrn_serialize) enq_end(etrn_serialize_key);
5573 if (user_msg == NULL) smtp_printf("250 OK\r\n");
5574 else smtp_user_msg(US"250", user_msg);
5577 signal(SIGCHLD, oldsignal);
5582 done = synprot_error(L_smtp_syntax_error, 501, NULL,
5583 US"unexpected argument data");
5587 /* This currently happens only for NULLs, but could be extended. */
5590 done = synprot_error(L_smtp_syntax_error, 0, NULL, /* Just logs */
5591 US"NULL character(s) present (shown as '?')");
5592 smtp_printf("501 NULL characters are not allowed in SMTP commands\r\n");
5598 if (smtp_inend >= smtp_inbuffer + IN_BUFFER_SIZE)
5599 smtp_inend = smtp_inbuffer + IN_BUFFER_SIZE - 1;
5600 c = smtp_inend - smtp_inptr;
5601 if (c > 150) c = 150;
5603 incomplete_transaction_log(US"sync failure");
5604 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP protocol synchronization error "
5605 "(next input sent too soon: pipelining was%s advertised): "
5606 "rejected \"%s\" %s next input=\"%s\"",
5607 pipelining_advertised? "" : " not",
5608 smtp_cmd_buffer, host_and_ident(TRUE),
5609 string_printing(smtp_inptr));
5610 smtp_notquit_exit(US"synchronization-error", US"554",
5611 US"SMTP synchronization error");
5612 done = 1; /* Pretend eof - drops connection */
5616 case TOO_MANY_NONMAIL_CMD:
5617 s = smtp_cmd_buffer;
5618 while (*s != 0 && !isspace(*s)) s++;
5619 incomplete_transaction_log(US"too many non-mail commands");
5620 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
5621 "nonmail commands (last was \"%.*s\")", host_and_ident(FALSE),
5622 (int)(s - smtp_cmd_buffer), smtp_cmd_buffer);
5623 smtp_notquit_exit(US"bad-commands", US"554", US"Too many nonmail commands");
5624 done = 1; /* Pretend eof - drops connection */
5627 #ifdef SUPPORT_PROXY
5628 case PROXY_FAIL_IGNORE_CMD:
5629 smtp_printf("503 Command refused, required Proxy negotiation failed\r\n");
5634 if (unknown_command_count++ >= smtp_max_unknown_commands)
5636 log_write(L_smtp_syntax_error, LOG_MAIN,
5637 "SMTP syntax error in \"%s\" %s %s",
5638 string_printing(smtp_cmd_buffer), host_and_ident(TRUE),
5639 US"unrecognized command");
5640 incomplete_transaction_log(US"unrecognized command");
5641 smtp_notquit_exit(US"bad-commands", US"500",
5642 US"Too many unrecognized commands");
5644 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
5645 "unrecognized commands (last was \"%s\")", host_and_ident(FALSE),
5646 string_printing(smtp_cmd_buffer));
5649 done = synprot_error(L_smtp_syntax_error, 500, NULL,
5650 US"unrecognized command");
5654 /* This label is used by goto's inside loops that want to break out to
5655 the end of the command-processing loop. */
5658 last_was_rej_mail = was_rej_mail; /* Remember some last commands for */
5659 last_was_rcpt = was_rcpt; /* protocol error handling */
5663 return done - 2; /* Convert yield values */
5668 /* End of smtp_in.c */