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. Normally, the checks happen when
318 commands are read: Exim ensures that there is no more input in the input buffer.
319 In normal cases, the response to the command will be fast, and there is no
322 However, for some commands an ACL is run, and that can include delays. In those
323 cases, it is useful to do another check on the input just before sending the
324 response. This also applies at the start of a connection. This function does
325 that check by means of the select() function, as long as the facility is not
326 disabled or inappropriate. A failure of select() is ignored.
328 When there is unwanted input, we read it so that it appears in the log of the
332 Returns: TRUE if all is well; FALSE if there is input pending
336 wouldblock_reading(void)
340 struct timeval tzero;
343 if (tls_in.active >= 0)
344 return !tls_could_read();
347 if (smtp_inptr < smtp_inend)
350 fd = fileno(smtp_in);
355 rc = select(fd + 1, (SELECT_ARG2_TYPE *)&fds, NULL, NULL, &tzero);
357 if (rc <= 0) return TRUE; /* Not ready to read */
358 rc = smtp_getc(GETC_BUFFER_UNLIMITED);
359 if (rc < 0) return TRUE; /* End of file or error */
362 rc = smtp_inend - smtp_inptr;
363 if (rc > 150) rc = 150;
371 if (!smtp_enforce_sync || sender_host_address == NULL || sender_host_notsocket)
374 return wouldblock_reading();
378 /* If there's input waiting (and we're doing pipelineing) then we can pipeline
379 a reponse with the one following. */
382 pipeline_response(void)
384 if ( !smtp_enforce_sync || !sender_host_address
385 || sender_host_notsocket || !pipelining_advertised)
388 return !wouldblock_reading();
393 /*************************************************
394 * Log incomplete transactions *
395 *************************************************/
397 /* This function is called after a transaction has been aborted by RSET, QUIT,
398 connection drops or other errors. It logs the envelope information received
399 so far in order to preserve address verification attempts.
401 Argument: string to indicate what aborted the transaction
406 incomplete_transaction_log(uschar *what)
408 if (sender_address == NULL || /* No transaction in progress */
409 !LOGGING(smtp_incomplete_transaction))
412 /* Build list of recipients for logging */
414 if (recipients_count > 0)
417 raw_recipients = store_get(recipients_count * sizeof(uschar *));
418 for (i = 0; i < recipients_count; i++)
419 raw_recipients[i] = recipients_list[i].address;
420 raw_recipients_count = recipients_count;
423 log_write(L_smtp_incomplete_transaction, LOG_MAIN|LOG_SENDER|LOG_RECIPIENTS,
424 "%s incomplete transaction (%s)", host_and_ident(TRUE), what);
430 /* Refill the buffer, and notify DKIM verification code.
431 Return false for error or EOF.
435 smtp_refill(unsigned lim)
438 if (!smtp_out) return FALSE;
440 if (smtp_receive_timeout > 0) alarm(smtp_receive_timeout);
442 /* Limit amount read, so non-message data is not fed to DKIM */
444 rc = read(fileno(smtp_in), smtp_inbuffer, MIN(IN_BUFFER_SIZE, lim));
449 /* Must put the error text in fixed store, because this might be during
450 header reading, where it releases unused store above the header. */
453 smtp_had_error = save_errno;
454 smtp_read_error = string_copy_malloc(
455 string_sprintf(" (error: %s)", strerror(save_errno)));
457 else smtp_had_eof = 1;
461 dkim_exim_verify_feed(smtp_inbuffer, rc);
463 smtp_inend = smtp_inbuffer + rc;
464 smtp_inptr = smtp_inbuffer;
468 /*************************************************
469 * SMTP version of getc() *
470 *************************************************/
472 /* This gets the next byte from the SMTP input buffer. If the buffer is empty,
473 it flushes the output, and refills the buffer, with a timeout. The signal
474 handler is set appropriately by the calling function. This function is not used
475 after a connection has negotiated itself into an TLS/SSL state.
477 Arguments: lim Maximum amount to read/buffer
478 Returns: the next character or EOF
482 smtp_getc(unsigned lim)
484 if (smtp_inptr >= smtp_inend)
485 if (!smtp_refill(lim))
487 return *smtp_inptr++;
491 smtp_getbuf(unsigned * len)
496 if (smtp_inptr >= smtp_inend)
497 if (!smtp_refill(*len))
498 { *len = 0; return NULL; }
500 if ((size = smtp_inend - smtp_inptr) > *len) size = *len;
511 int n = smtp_inend - smtp_inptr;
513 dkim_exim_verify_feed(smtp_inptr, n);
518 /* Get a byte from the smtp input, in CHUNKING mode. Handle ack of the
519 previous BDAT chunk and getting new ones when we run out. Uses the
520 underlying smtp_getc or tls_getc both for that and for getting the
521 (buffered) data byte. EOD signals (an expected) no further data.
522 ERR signals a protocol error, and EOF a closed input stream.
524 Called from read_bdat_smtp() in receive.c for the message body, but also
525 by the headers read loop in receive_msg(); manipulates chunking_state
526 to handle the BDAT command/response.
527 Placed here due to the correlation with the above smtp_getc(), which it wraps,
528 and also by the need to do smtp command/response handling.
530 Arguments: lim (ignored)
531 Returns: the next character or ERR, EOD or EOF
535 bdat_getc(unsigned lim)
537 uschar * user_msg = NULL;
546 if (chunking_data_left > 0)
547 return lwr_receive_getc(chunking_data_left--);
549 receive_getc = lwr_receive_getc;
550 receive_getbuf = lwr_receive_getbuf;
551 receive_ungetc = lwr_receive_ungetc;
553 dkim_save = dkim_collect_input;
554 dkim_collect_input = FALSE;
557 /* Unless PIPELINING was offered, there should be no next command
558 until after we ack that chunk */
560 if (!pipelining_advertised && !check_sync())
562 unsigned n = smtp_inend - smtp_inptr;
565 incomplete_transaction_log(US"sync failure");
566 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP protocol synchronization error "
567 "(next input sent too soon: pipelining was not advertised): "
568 "rejected \"%s\" %s next input=\"%s\"",
569 smtp_cmd_buffer, host_and_ident(TRUE),
570 string_printing(string_copyn(smtp_inptr, n)));
571 (void) synprot_error(L_smtp_protocol_error, 554, NULL,
572 US"SMTP synchronization error");
573 goto repeat_until_rset;
576 /* If not the last, ack the received chunk. The last response is delayed
577 until after the data ACL decides on it */
579 if (chunking_state == CHUNKING_LAST)
582 dkim_exim_verify_feed(NULL, 0); /* notify EOD */
587 smtp_printf("250 %u byte chunk received\r\n", FALSE, chunking_datasize);
588 chunking_state = CHUNKING_OFFERED;
589 DEBUG(D_receive) debug_printf("chunking state %d\n", (int)chunking_state);
591 /* Expect another BDAT cmd from input. RFC 3030 says nothing about
592 QUIT, RSET or NOOP but handling them seems obvious */
595 switch(smtp_read_command(TRUE, 1))
598 (void) synprot_error(L_smtp_protocol_error, 503, NULL,
599 US"only BDAT permissible after non-LAST BDAT");
602 switch(smtp_read_command(TRUE, 1))
604 case QUIT_CMD: smtp_quit_handler(&user_msg, &log_msg); /*FALLTHROUGH */
605 case EOF_CMD: return EOF;
606 case RSET_CMD: smtp_rset_handler(); return ERR;
607 default: if (synprot_error(L_smtp_protocol_error, 503, NULL,
608 US"only RSET accepted now") > 0)
610 goto repeat_until_rset;
614 smtp_quit_handler(&user_msg, &log_msg);
625 smtp_printf("250 OK\r\n", FALSE);
632 if (sscanf(CS smtp_cmd_data, "%u %n", &chunking_datasize, &n) < 1)
634 (void) synprot_error(L_smtp_protocol_error, 501, NULL,
635 US"missing size for BDAT command");
638 chunking_state = strcmpic(smtp_cmd_data+n, US"LAST") == 0
639 ? CHUNKING_LAST : CHUNKING_ACTIVE;
640 chunking_data_left = chunking_datasize;
641 DEBUG(D_receive) debug_printf("chunking state %d, %d bytes\n",
642 (int)chunking_state, chunking_data_left);
644 if (chunking_datasize == 0)
645 if (chunking_state == CHUNKING_LAST)
649 (void) synprot_error(L_smtp_protocol_error, 504, NULL,
650 US"zero size for BDAT command");
651 goto repeat_until_rset;
654 receive_getc = bdat_getc;
655 receive_getbuf = bdat_getbuf;
656 receive_ungetc = bdat_ungetc;
658 dkim_collect_input = dkim_save;
660 break; /* to top of main loop */
667 bdat_getbuf(unsigned * len)
671 if (chunking_data_left <= 0)
672 { *len = 0; return NULL; }
674 if (*len > chunking_data_left) *len = chunking_data_left;
675 buf = lwr_receive_getbuf(len); /* Either smtp_getbuf or tls_getbuf */
676 chunking_data_left -= *len;
681 bdat_flush_data(void)
683 unsigned n = chunking_data_left;
684 (void) bdat_getbuf(&n);
686 receive_getc = lwr_receive_getc;
687 receive_getbuf = lwr_receive_getbuf;
688 receive_ungetc = lwr_receive_ungetc;
690 if (chunking_state != CHUNKING_LAST)
692 chunking_state = CHUNKING_OFFERED;
693 DEBUG(D_receive) debug_printf("chunking state %d\n", (int)chunking_state);
700 /*************************************************
701 * SMTP version of ungetc() *
702 *************************************************/
704 /* Puts a character back in the input buffer. Only ever
710 Returns: the character
724 chunking_data_left++;
725 return lwr_receive_ungetc(ch);
730 /*************************************************
731 * SMTP version of feof() *
732 *************************************************/
734 /* Tests for a previous EOF
737 Returns: non-zero if the eof flag is set
749 /*************************************************
750 * SMTP version of ferror() *
751 *************************************************/
753 /* Tests for a previous read error, and returns with errno
754 restored to what it was when the error was detected.
757 Returns: non-zero if the error flag is set
763 errno = smtp_had_error;
764 return smtp_had_error;
769 /*************************************************
770 * Test for characters in the SMTP buffer *
771 *************************************************/
773 /* Used at the end of a message
782 return smtp_inptr < smtp_inend;
787 /*************************************************
788 * Write formatted string to SMTP channel *
789 *************************************************/
791 /* This is a separate function so that we don't have to repeat everything for
792 TLS support or debugging. It is global so that the daemon and the
793 authentication functions can use it. It does not return any error indication,
794 because major problems such as dropped connections won't show up till an output
795 flush for non-TLS connections. The smtp_fflush() function is available for
796 checking that: for convenience, TLS output errors are remembered here so that
797 they are also picked up later by smtp_fflush().
801 more further data expected
802 ... optional arguments
808 smtp_printf(const char *format, BOOL more, ...)
813 smtp_vprintf(format, more, ap);
817 /* This is split off so that verify.c:respond_printf() can, in effect, call
818 smtp_printf(), bearing in mind that in C a vararg function can't directly
819 call another vararg function, only a function which accepts a va_list. */
822 smtp_vprintf(const char *format, BOOL more, va_list ap)
826 yield = string_vformat(big_buffer, big_buffer_size, format, ap);
830 void *reset_point = store_get(0);
831 uschar *msg_copy, *cr, *end;
832 msg_copy = string_copy(big_buffer);
833 end = msg_copy + Ustrlen(msg_copy);
834 while ((cr = Ustrchr(msg_copy, '\r')) != NULL) /* lose CRs */
835 memmove(cr, cr + 1, (end--) - cr);
836 debug_printf("SMTP>> %s", msg_copy);
837 store_reset(reset_point);
842 log_write(0, LOG_MAIN|LOG_PANIC, "string too large in smtp_printf()");
843 smtp_closedown(US"Unexpected error");
844 exim_exit(EXIT_FAILURE);
847 /* If this is the first output for a (non-batch) RCPT command, see if all RCPTs
848 have had the same. Note: this code is also present in smtp_respond(). It would
849 be tidier to have it only in one place, but when it was added, it was easier to
850 do it that way, so as not to have to mess with the code for the RCPT command,
851 which sometimes uses smtp_printf() and sometimes smtp_respond(). */
853 if (rcpt_in_progress)
855 if (rcpt_smtp_response == NULL)
856 rcpt_smtp_response = string_copy(big_buffer);
857 else if (rcpt_smtp_response_same &&
858 Ustrcmp(rcpt_smtp_response, big_buffer) != 0)
859 rcpt_smtp_response_same = FALSE;
860 rcpt_in_progress = FALSE;
863 /* Now write the string */
866 if (tls_in.active >= 0)
868 if (tls_write(TRUE, big_buffer, Ustrlen(big_buffer), more) < 0)
869 smtp_write_error = -1;
874 if (fprintf(smtp_out, "%s", big_buffer) < 0) smtp_write_error = -1;
879 /*************************************************
880 * Flush SMTP out and check for error *
881 *************************************************/
883 /* This function isn't currently used within Exim (it detects errors when it
884 tries to read the next SMTP input), but is available for use in local_scan().
885 For non-TLS connections, it flushes the output and checks for errors. For
886 TLS-connections, it checks for a previously-detected TLS write error.
889 Returns: 0 for no error; -1 after an error
895 if (tls_in.active < 0 && fflush(smtp_out) != 0) smtp_write_error = -1;
896 return smtp_write_error;
901 /*************************************************
902 * SMTP command read timeout *
903 *************************************************/
905 /* Signal handler for timing out incoming SMTP commands. This attempts to
908 Argument: signal number (SIGALRM)
913 command_timeout_handler(int sig)
915 sig = sig; /* Keep picky compilers happy */
916 log_write(L_lost_incoming_connection,
917 LOG_MAIN, "SMTP command timeout on%s connection from %s",
918 (tls_in.active >= 0)? " TLS" : "",
919 host_and_ident(FALSE));
920 if (smtp_batched_input)
921 moan_smtp_batch(NULL, "421 SMTP command timeout"); /* Does not return */
922 smtp_notquit_exit(US"command-timeout", US"421",
923 US"%s: SMTP command timeout - closing connection", smtp_active_hostname);
924 exim_exit(EXIT_FAILURE);
929 /*************************************************
931 *************************************************/
933 /* Signal handler for handling SIGTERM. Again, try to finish tidily.
935 Argument: signal number (SIGTERM)
940 command_sigterm_handler(int sig)
942 sig = sig; /* Keep picky compilers happy */
943 log_write(0, LOG_MAIN, "%s closed after SIGTERM", smtp_get_connection_info());
944 if (smtp_batched_input)
945 moan_smtp_batch(NULL, "421 SIGTERM received"); /* Does not return */
946 smtp_notquit_exit(US"signal-exit", US"421",
947 US"%s: Service not available - closing connection", smtp_active_hostname);
948 exim_exit(EXIT_FAILURE);
955 /*************************************************
956 * Restore socket timeout to previous value *
957 *************************************************/
958 /* If the previous value was successfully retrieved, restore
959 it before returning control to the non-proxy routines
961 Arguments: fd - File descriptor for input
962 get_ok - Successfully retrieved previous values
963 tvtmp - Time struct with previous values
964 vslen - Length of time struct
968 restore_socket_timeout(int fd, int get_ok, struct timeval * tvtmp, socklen_t vslen)
971 (void) setsockopt(fd, SOL_SOCKET, SO_RCVTIMEO, CS tvtmp, vslen);
974 /*************************************************
975 * Check if host is required proxy host *
976 *************************************************/
977 /* The function determines if inbound host will be a regular smtp host
978 or if it is configured that it must use Proxy Protocol. A local
986 check_proxy_protocol_host()
990 if ( sender_host_address
991 && (rc = verify_check_this_host(CUSS &hosts_proxy, NULL, NULL,
992 sender_host_address, NULL)) == OK)
995 debug_printf("Detected proxy protocol configured host\n");
996 proxy_session = TRUE;
998 return proxy_session;
1002 /*************************************************
1003 * Read data until newline or end of buffer *
1004 *************************************************/
1005 /* While SMTP is server-speaks-first, TLS is client-speaks-first, so we can't
1006 read an entire buffer and assume there will be nothing past a proxy protocol
1007 header. Our approach normally is to use stdio, but again that relies upon
1008 "STARTTLS\r\n" and a server response before the client starts TLS handshake, or
1009 reading _nothing_ before client TLS handshake. So we don't want to use the
1010 usual buffering reads which may read enough to block TLS starting.
1012 So unfortunately we're down to "read one byte at a time, with a syscall each,
1013 and expect a little overhead", for all proxy-opened connections which are v1,
1014 just to handle the TLS-on-connect case. Since SSL functions wrap the
1015 underlying fd, we can't assume that we can feed them any already-read content.
1017 We need to know where to read to, the max capacity, and we'll read until we
1018 get a CR and one more character. Let the caller scream if it's CR+!LF.
1020 Return the amount read.
1024 swallow_until_crlf(int fd, uschar *base, int already, int capacity)
1026 uschar *to = base + already;
1032 /* For "PROXY UNKNOWN\r\n" we, at time of writing, expect to have read
1033 up through the \r; for the _normal_ case, we haven't yet seen the \r. */
1035 cr = memchr(base, '\r', already);
1038 if ((cr - base) < already - 1)
1040 /* \r and presumed \n already within what we have; probably not
1041 actually proxy protocol, but abort cleanly. */
1044 /* \r is last character read, just need one more. */
1048 while (capacity > 0)
1050 do { ret = recv(fd, to, 1, 0); } while (ret == -1 && errno == EINTR);
1062 /* reached end without having room for a final newline, abort */
1067 /*************************************************
1068 * Setup host for proxy protocol *
1069 *************************************************/
1070 /* The function configures the connection based on a header from the
1071 inbound host to use Proxy Protocol. The specification is very exact
1072 so exit with an error if do not find the exact required pieces. This
1073 includes an incorrect number of spaces separating args.
1076 Returns: Boolean success
1080 setup_proxy_protocol_host()
1092 struct { /* TCP/UDP over IPv4, len = 12 */
1098 struct { /* TCP/UDP over IPv6, len = 36 */
1099 uint8_t src_addr[16];
1100 uint8_t dst_addr[16];
1104 struct { /* AF_UNIX sockets, len = 216 */
1105 uschar src_addr[108];
1106 uschar dst_addr[108];
1112 /* Temp variables used in PPv2 address:port parsing */
1114 char tmpip[INET_ADDRSTRLEN];
1115 struct sockaddr_in tmpaddr;
1116 char tmpip6[INET6_ADDRSTRLEN];
1117 struct sockaddr_in6 tmpaddr6;
1119 /* We can't read "all data until end" because while SMTP is
1120 server-speaks-first, the TLS handshake is client-speaks-first, so for
1121 TLS-on-connect ports the proxy protocol header will usually be immediately
1122 followed by a TLS handshake, and with N TLS libraries, we can't reliably
1123 reinject data for reading by those. So instead we first read "enough to be
1124 safely read within the header, and figure out how much more to read".
1125 For v1 we will later read to the end-of-line, for v2 we will read based upon
1128 The v2 sig is 12 octets, and another 4 gets us the length, so we know how much
1129 data is needed total. For v1, where the line looks like:
1130 PROXY TCPn L3src L3dest SrcPort DestPort \r\n
1132 However, for v1 there's also `PROXY UNKNOWN\r\n` which is only 15 octets.
1133 We seem to support that. So, if we read 14 octets then we can tell if we're
1134 v2 or v1. If we're v1, we can continue reading as normal.
1136 If we're v2, we can't slurp up the entire header. We need the length in the
1137 15th & 16th octets, then to read everything after that.
1139 So to safely handle v1 and v2, with client-sent-first supported correctly,
1140 we have to do a minimum of 3 read calls, not 1. Eww.
1143 #define PROXY_INITIAL_READ 14
1144 #define PROXY_V2_HEADER_SIZE 16
1145 #if PROXY_INITIAL_READ > PROXY_V2_HEADER_SIZE
1146 # error Code bug in sizes of data to read for proxy usage
1151 int fd = fileno(smtp_in);
1152 const char v2sig[12] = "\x0D\x0A\x0D\x0A\x00\x0D\x0A\x51\x55\x49\x54\x0A";
1153 uschar * iptype; /* To display debug info */
1155 struct timeval tvtmp;
1156 socklen_t vslen = sizeof(struct timeval);
1159 /* Save current socket timeout values */
1160 get_ok = getsockopt(fd, SOL_SOCKET, SO_RCVTIMEO, CS &tvtmp, &vslen);
1162 /* Proxy Protocol host must send header within a short time
1163 (default 3 seconds) or it's considered invalid */
1164 tv.tv_sec = PROXY_NEGOTIATION_TIMEOUT_SEC;
1165 tv.tv_usec = PROXY_NEGOTIATION_TIMEOUT_USEC;
1166 if (setsockopt(fd, SOL_SOCKET, SO_RCVTIMEO, CS &tv, sizeof(tv)) < 0)
1171 /* The inbound host was declared to be a Proxy Protocol host, so
1172 don't do a PEEK into the data, actually slurp up enough to be
1173 "safe". Can't take it all because TLS-on-connect clients follow
1174 immediately with TLS handshake. */
1175 ret = recv(fd, &hdr, PROXY_INITIAL_READ, 0);
1177 while (ret == -1 && errno == EINTR);
1182 /* For v2, handle reading the length, and then the rest. */
1183 if ((ret == PROXY_INITIAL_READ) && (memcmp(&hdr.v2, v2sig, sizeof(v2sig)) == 0))
1188 /* First get the length fields. */
1191 retmore = recv(fd, (uschar*)&hdr + ret, PROXY_V2_HEADER_SIZE - PROXY_INITIAL_READ, 0);
1192 } while (retmore == -1 && errno == EINTR);
1197 ver = (hdr.v2.ver_cmd & 0xf0) >> 4;
1199 /* May 2014: haproxy combined the version and command into one byte to
1200 allow two full bytes for the length field in order to proxy SSL
1201 connections. SSL Proxy is not supported in this version of Exim, but
1202 must still separate values here. */
1206 DEBUG(D_receive) debug_printf("Invalid Proxy Protocol version: %d\n", ver);
1210 /* The v2 header will always be 16 bytes per the spec. */
1211 size = 16 + ntohs(hdr.v2.len);
1212 DEBUG(D_receive) debug_printf("Detected PROXYv2 header, size %d (limit %d)\n",
1213 size, (int)sizeof(hdr));
1215 /* We should now have 16 octets (PROXY_V2_HEADER_SIZE), and we know the total
1216 amount that we need. Double-check that the size is not unreasonable, then
1218 if (size > sizeof(hdr))
1220 DEBUG(D_receive) debug_printf("PROXYv2 header size unreasonably large; security attack?\n");
1228 retmore = recv(fd, (uschar*)&hdr + ret, size-ret, 0);
1229 } while (retmore == -1 && errno == EINTR);
1233 DEBUG(D_receive) debug_printf("PROXYv2: have %d/%d required octets\n", ret, size);
1234 } while (ret < size);
1236 } /* end scope for getting rest of data for v2 */
1238 /* At this point: if PROXYv2, we've read the exact size required for all data;
1239 if PROXYv1 then we've read "less than required for any valid line" and should
1242 if (ret >= 16 && memcmp(&hdr.v2, v2sig, 12) == 0)
1244 uint8_t cmd = (hdr.v2.ver_cmd & 0x0f);
1248 case 0x01: /* PROXY command */
1251 case 0x11: /* TCPv4 address type */
1253 tmpaddr.sin_addr.s_addr = hdr.v2.addr.ip4.src_addr;
1254 inet_ntop(AF_INET, &tmpaddr.sin_addr, CS &tmpip, sizeof(tmpip));
1255 if (!string_is_ip_address(US tmpip, NULL))
1257 DEBUG(D_receive) debug_printf("Invalid %s source IP\n", iptype);
1260 proxy_local_address = sender_host_address;
1261 sender_host_address = string_copy(US tmpip);
1262 tmpport = ntohs(hdr.v2.addr.ip4.src_port);
1263 proxy_local_port = sender_host_port;
1264 sender_host_port = tmpport;
1265 /* Save dest ip/port */
1266 tmpaddr.sin_addr.s_addr = hdr.v2.addr.ip4.dst_addr;
1267 inet_ntop(AF_INET, &tmpaddr.sin_addr, CS &tmpip, sizeof(tmpip));
1268 if (!string_is_ip_address(US tmpip, NULL))
1270 DEBUG(D_receive) debug_printf("Invalid %s dest port\n", iptype);
1273 proxy_external_address = string_copy(US tmpip);
1274 tmpport = ntohs(hdr.v2.addr.ip4.dst_port);
1275 proxy_external_port = tmpport;
1277 case 0x21: /* TCPv6 address type */
1279 memmove(tmpaddr6.sin6_addr.s6_addr, hdr.v2.addr.ip6.src_addr, 16);
1280 inet_ntop(AF_INET6, &tmpaddr6.sin6_addr, CS &tmpip6, sizeof(tmpip6));
1281 if (!string_is_ip_address(US tmpip6, NULL))
1283 DEBUG(D_receive) debug_printf("Invalid %s source IP\n", iptype);
1286 proxy_local_address = sender_host_address;
1287 sender_host_address = string_copy(US tmpip6);
1288 tmpport = ntohs(hdr.v2.addr.ip6.src_port);
1289 proxy_local_port = sender_host_port;
1290 sender_host_port = tmpport;
1291 /* Save dest ip/port */
1292 memmove(tmpaddr6.sin6_addr.s6_addr, hdr.v2.addr.ip6.dst_addr, 16);
1293 inet_ntop(AF_INET6, &tmpaddr6.sin6_addr, CS &tmpip6, sizeof(tmpip6));
1294 if (!string_is_ip_address(US tmpip6, NULL))
1296 DEBUG(D_receive) debug_printf("Invalid %s dest port\n", iptype);
1299 proxy_external_address = string_copy(US tmpip6);
1300 tmpport = ntohs(hdr.v2.addr.ip6.dst_port);
1301 proxy_external_port = tmpport;
1305 debug_printf("Unsupported PROXYv2 connection type: 0x%02x\n",
1309 /* Unsupported protocol, keep local connection address */
1311 case 0x00: /* LOCAL command */
1312 /* Keep local connection address for LOCAL */
1317 debug_printf("Unsupported PROXYv2 command: 0x%x\n", cmd);
1321 else if (ret >= 8 && memcmp(hdr.v1.line, "PROXY", 5) == 0)
1325 uschar *sp; /* Utility variables follow */
1330 /* get the rest of the line */
1331 r2 = swallow_until_crlf(fd, (uschar*)&hdr, ret, sizeof(hdr)-ret);
1336 p = string_copy(hdr.v1.line);
1337 end = memchr(p, '\r', ret - 1);
1339 if (!end || (end == (uschar*)&hdr + ret) || end[1] != '\n')
1341 DEBUG(D_receive) debug_printf("Partial or invalid PROXY header\n");
1344 *end = '\0'; /* Terminate the string */
1345 size = end + 2 - p; /* Skip header + CRLF */
1346 DEBUG(D_receive) debug_printf("Detected PROXYv1 header\n");
1347 DEBUG(D_receive) debug_printf("Bytes read not within PROXY header: %d\n", ret - size);
1348 /* Step through the string looking for the required fields. Ensure
1349 strict adherence to required formatting, exit for any error. */
1351 if (!isspace(*(p++)))
1353 DEBUG(D_receive) debug_printf("Missing space after PROXY command\n");
1356 if (!Ustrncmp(p, CCS"TCP4", 4))
1358 else if (!Ustrncmp(p,CCS"TCP6", 4))
1360 else if (!Ustrncmp(p,CCS"UNKNOWN", 7))
1362 iptype = US"Unknown";
1367 DEBUG(D_receive) debug_printf("Invalid TCP type\n");
1371 p += Ustrlen(iptype);
1372 if (!isspace(*(p++)))
1374 DEBUG(D_receive) debug_printf("Missing space after TCP4/6 command\n");
1377 /* Find the end of the arg */
1378 if ((sp = Ustrchr(p, ' ')) == NULL)
1381 debug_printf("Did not find proxied src %s\n", iptype);
1385 if(!string_is_ip_address(p, NULL))
1388 debug_printf("Proxied src arg is not an %s address\n", iptype);
1391 proxy_local_address = sender_host_address;
1392 sender_host_address = p;
1394 if ((sp = Ustrchr(p, ' ')) == NULL)
1397 debug_printf("Did not find proxy dest %s\n", iptype);
1401 if(!string_is_ip_address(p, NULL))
1404 debug_printf("Proxy dest arg is not an %s address\n", iptype);
1407 proxy_external_address = p;
1409 if ((sp = Ustrchr(p, ' ')) == NULL)
1411 DEBUG(D_receive) debug_printf("Did not find proxied src port\n");
1415 tmp_port = strtol(CCS p, &endc, 10);
1416 if (*endc || tmp_port == 0)
1419 debug_printf("Proxied src port '%s' not an integer\n", p);
1422 proxy_local_port = sender_host_port;
1423 sender_host_port = tmp_port;
1425 if ((sp = Ustrchr(p, '\0')) == NULL)
1427 DEBUG(D_receive) debug_printf("Did not find proxy dest port\n");
1430 tmp_port = strtol(CCS p, &endc, 10);
1431 if (*endc || tmp_port == 0)
1434 debug_printf("Proxy dest port '%s' not an integer\n", p);
1437 proxy_external_port = tmp_port;
1438 /* Already checked for /r /n above. Good V1 header received. */
1442 /* Wrong protocol */
1443 DEBUG(D_receive) debug_printf("Invalid proxy protocol version negotiation\n");
1444 (void) swallow_until_crlf(fd, (uschar*)&hdr, ret, sizeof(hdr)-ret);
1450 debug_printf("Valid %s sender from Proxy Protocol header\n", iptype);
1451 yield = proxy_session;
1453 /* Don't flush any potential buffer contents. Any input on proxyfail
1454 should cause a synchronization failure */
1457 restore_socket_timeout(fd, get_ok, &tvtmp, vslen);
1462 sender_host_name = NULL;
1463 (void) host_name_lookup();
1464 host_build_sender_fullhost();
1468 proxy_session_failed = TRUE;
1470 debug_printf("Failure to extract proxied host, only QUIT allowed\n");
1477 /*************************************************
1478 * Read one command line *
1479 *************************************************/
1481 /* Strictly, SMTP commands coming over the net are supposed to end with CRLF.
1482 There are sites that don't do this, and in any case internal SMTP probably
1483 should check only for LF. Consequently, we check here for LF only. The line
1484 ends up with [CR]LF removed from its end. If we get an overlong line, treat as
1485 an unknown command. The command is read into the global smtp_cmd_buffer so that
1486 it is available via $smtp_command.
1488 The character reading routine sets up a timeout for each block actually read
1489 from the input (which may contain more than one command). We set up a special
1490 signal handler that closes down the session on a timeout. Control does not
1491 return when it runs.
1494 check_sync if TRUE, check synchronization rules if global option is TRUE
1495 buffer_lim maximum to buffer in lower layer
1497 Returns: a code identifying the command (enumerated above)
1501 smtp_read_command(BOOL check_sync, unsigned buffer_lim)
1506 BOOL hadnull = FALSE;
1508 os_non_restarting_signal(SIGALRM, command_timeout_handler);
1510 while ((c = (receive_getc)(buffer_lim)) != '\n' && c != EOF)
1512 if (ptr >= SMTP_CMD_BUFFER_SIZE)
1514 os_non_restarting_signal(SIGALRM, sigalrm_handler);
1522 smtp_cmd_buffer[ptr++] = c;
1525 receive_linecount++; /* For BSMTP errors */
1526 os_non_restarting_signal(SIGALRM, sigalrm_handler);
1528 /* If hit end of file, return pseudo EOF command. Whether we have a
1529 part-line already read doesn't matter, since this is an error state. */
1531 if (c == EOF) return EOF_CMD;
1533 /* Remove any CR and white space at the end of the line, and terminate the
1536 while (ptr > 0 && isspace(smtp_cmd_buffer[ptr-1])) ptr--;
1537 smtp_cmd_buffer[ptr] = 0;
1539 DEBUG(D_receive) debug_printf("SMTP<< %s\n", smtp_cmd_buffer);
1541 /* NULLs are not allowed in SMTP commands */
1543 if (hadnull) return BADCHAR_CMD;
1545 /* Scan command list and return identity, having set the data pointer
1546 to the start of the actual data characters. Check for SMTP synchronization
1549 for (p = cmd_list; p < cmd_list_end; p++)
1551 #ifdef SUPPORT_PROXY
1552 /* Only allow QUIT command if Proxy Protocol parsing failed */
1553 if (proxy_session && proxy_session_failed && p->cmd != QUIT_CMD)
1557 && strncmpic(smtp_cmd_buffer, US p->name, p->len) == 0
1558 && ( smtp_cmd_buffer[p->len-1] == ':' /* "mail from:" or "rcpt to:" */
1559 || smtp_cmd_buffer[p->len] == 0
1560 || smtp_cmd_buffer[p->len] == ' '
1563 if (smtp_inptr < smtp_inend && /* Outstanding input */
1564 p->cmd < sync_cmd_limit && /* Command should sync */
1565 check_sync && /* Local flag set */
1566 smtp_enforce_sync && /* Global flag set */
1567 sender_host_address != NULL && /* Not local input */
1568 !sender_host_notsocket) /* Really is a socket */
1571 /* The variables $smtp_command and $smtp_command_argument point into the
1572 unmodified input buffer. A copy of the latter is taken for actual
1573 processing, so that it can be chopped up into separate parts if necessary,
1574 for example, when processing a MAIL command options such as SIZE that can
1575 follow the sender address. */
1577 smtp_cmd_argument = smtp_cmd_buffer + p->len;
1578 while (isspace(*smtp_cmd_argument)) smtp_cmd_argument++;
1579 Ustrcpy(smtp_data_buffer, smtp_cmd_argument);
1580 smtp_cmd_data = smtp_data_buffer;
1582 /* Count non-mail commands from those hosts that are controlled in this
1583 way. The default is all hosts. We don't waste effort checking the list
1584 until we get a non-mail command, but then cache the result to save checking
1585 again. If there's a DEFER while checking the host, assume it's in the list.
1587 Note that one instance of RSET, EHLO/HELO, and STARTTLS is allowed at the
1588 start of each incoming message by fiddling with the value in the table. */
1590 if (!p->is_mail_cmd)
1592 if (count_nonmail == TRUE_UNSET) count_nonmail =
1593 verify_check_host(&smtp_accept_max_nonmail_hosts) != FAIL;
1594 if (count_nonmail && ++nonmail_command_count > smtp_accept_max_nonmail)
1595 return TOO_MANY_NONMAIL_CMD;
1598 /* If there is data for a command that does not expect it, generate the
1601 return (p->has_arg || *smtp_cmd_data == 0)? p->cmd : BADARG_CMD;
1605 #ifdef SUPPORT_PROXY
1606 /* Only allow QUIT command if Proxy Protocol parsing failed */
1607 if (proxy_session && proxy_session_failed)
1608 return PROXY_FAIL_IGNORE_CMD;
1611 /* Enforce synchronization for unknown commands */
1613 if (smtp_inptr < smtp_inend && /* Outstanding input */
1614 check_sync && /* Local flag set */
1615 smtp_enforce_sync && /* Global flag set */
1616 sender_host_address != NULL && /* Not local input */
1617 !sender_host_notsocket) /* Really is a socket */
1625 /*************************************************
1626 * Forced closedown of call *
1627 *************************************************/
1629 /* This function is called from log.c when Exim is dying because of a serious
1630 disaster, and also from some other places. If an incoming non-batched SMTP
1631 channel is open, it swallows the rest of the incoming message if in the DATA
1632 phase, sends the reply string, and gives an error to all subsequent commands
1633 except QUIT. The existence of an SMTP call is detected by the non-NULLness of
1637 message SMTP reply string to send, excluding the code
1643 smtp_closedown(uschar *message)
1645 if (smtp_in == NULL || smtp_batched_input) return;
1646 receive_swallow_smtp();
1647 smtp_printf("421 %s\r\n", FALSE, message);
1649 for (;;) switch(smtp_read_command(FALSE, GETC_BUFFER_UNLIMITED))
1655 smtp_printf("221 %s closing connection\r\n", FALSE, smtp_active_hostname);
1660 smtp_printf("250 Reset OK\r\n", FALSE);
1664 smtp_printf("421 %s\r\n", FALSE, message);
1672 /*************************************************
1673 * Set up connection info for logging *
1674 *************************************************/
1676 /* This function is called when logging information about an SMTP connection.
1677 It sets up appropriate source information, depending on the type of connection.
1678 If sender_fullhost is NULL, we are at a very early stage of the connection;
1679 just use the IP address.
1682 Returns: a string describing the connection
1686 smtp_get_connection_info(void)
1688 const uschar * hostname = sender_fullhost
1689 ? sender_fullhost : sender_host_address;
1692 return string_sprintf("SMTP connection from %s", hostname);
1694 if (sender_host_unknown || sender_host_notsocket)
1695 return string_sprintf("SMTP connection from %s", sender_ident);
1698 return string_sprintf("SMTP connection from %s (via inetd)", hostname);
1700 if (LOGGING(incoming_interface) && interface_address != NULL)
1701 return string_sprintf("SMTP connection from %s I=[%s]:%d", hostname,
1702 interface_address, interface_port);
1704 return string_sprintf("SMTP connection from %s", hostname);
1710 /* Append TLS-related information to a log line
1713 g String under construction: allocated string to extend, or NULL
1715 Returns: Allocated string or NULL
1718 s_tlslog(gstring * g)
1720 if (LOGGING(tls_cipher) && tls_in.cipher)
1721 g = string_append(g, 2, US" X=", tls_in.cipher);
1722 if (LOGGING(tls_certificate_verified) && tls_in.cipher)
1723 g = string_append(g, 2, US" CV=", tls_in.certificate_verified? "yes":"no");
1724 if (LOGGING(tls_peerdn) && tls_in.peerdn)
1725 g = string_append(g, 3, US" DN=\"", string_printing(tls_in.peerdn), US"\"");
1726 if (LOGGING(tls_sni) && tls_in.sni)
1727 g = string_append(g, 3, US" SNI=\"", string_printing(tls_in.sni), US"\"");
1732 /*************************************************
1733 * Log lack of MAIL if so configured *
1734 *************************************************/
1736 /* This function is called when an SMTP session ends. If the log selector
1737 smtp_no_mail is set, write a log line giving some details of what has happened
1738 in the SMTP session.
1745 smtp_log_no_mail(void)
1751 if (smtp_mailcmd_count > 0 || !LOGGING(smtp_no_mail))
1754 if (sender_host_authenticated != NULL)
1756 g = string_append(g, 2, US" A=", sender_host_authenticated);
1757 if (authenticated_id) g = string_append(g, 2, US":", authenticated_id);
1764 sep = smtp_connection_had[SMTP_HBUFF_SIZE-1] != SCH_NONE ? US" C=..." : US" C=";
1766 for (i = smtp_ch_index; i < SMTP_HBUFF_SIZE; i++)
1767 if (smtp_connection_had[i] != SCH_NONE)
1769 g = string_append(g, 2, sep, smtp_names[smtp_connection_had[i]]);
1773 for (i = 0; i < smtp_ch_index; i++)
1775 g = string_append(g, 2, sep, smtp_names[smtp_connection_had[i]]);
1779 if (!(s = string_from_gstring(g))) s = US"";
1781 log_write(0, LOG_MAIN, "no MAIL in %sSMTP connection from %s D=%s%s",
1782 tcp_in_fastopen ? US"TFO " : US"",
1783 host_and_ident(FALSE), string_timesince(&smtp_connection_start), s);
1787 /* Return list of recent smtp commands */
1793 gstring * list = NULL;
1796 for (i = smtp_ch_index; i < SMTP_HBUFF_SIZE; i++)
1797 if (smtp_connection_had[i] != SCH_NONE)
1798 list = string_append_listele(list, ',', smtp_names[smtp_connection_had[i]]);
1800 for (i = 0; i < smtp_ch_index; i++)
1801 list = string_append_listele(list, ',', smtp_names[smtp_connection_had[i]]);
1803 s = string_from_gstring(list);
1804 return s ? s : US"";
1810 /*************************************************
1811 * Check HELO line and set sender_helo_name *
1812 *************************************************/
1814 /* Check the format of a HELO line. The data for HELO/EHLO is supposed to be
1815 the domain name of the sending host, or an ip literal in square brackets. The
1816 argument is placed in sender_helo_name, which is in malloc store, because it
1817 must persist over multiple incoming messages. If helo_accept_junk is set, this
1818 host is permitted to send any old junk (needed for some broken hosts).
1819 Otherwise, helo_allow_chars can be used for rogue characters in general
1820 (typically people want to let in underscores).
1823 s the data portion of the line (already past any white space)
1825 Returns: TRUE or FALSE
1829 check_helo(uschar *s)
1832 uschar *end = s + Ustrlen(s);
1833 BOOL yield = helo_accept_junk;
1835 /* Discard any previous helo name */
1837 if (sender_helo_name != NULL)
1839 store_free(sender_helo_name);
1840 sender_helo_name = NULL;
1843 /* Skip tests if junk is permitted. */
1847 /* Allow the new standard form for IPv6 address literals, namely,
1848 [IPv6:....], and because someone is bound to use it, allow an equivalent
1849 IPv4 form. Allow plain addresses as well. */
1856 if (strncmpic(s, US"[IPv6:", 6) == 0)
1857 yield = (string_is_ip_address(s+6, NULL) == 6);
1858 else if (strncmpic(s, US"[IPv4:", 6) == 0)
1859 yield = (string_is_ip_address(s+6, NULL) == 4);
1861 yield = (string_is_ip_address(s+1, NULL) != 0);
1866 /* Non-literals must be alpha, dot, hyphen, plus any non-valid chars
1867 that have been configured (usually underscore - sigh). */
1874 if (!isalnum(*s) && *s != '.' && *s != '-' &&
1875 Ustrchr(helo_allow_chars, *s) == NULL)
1885 /* Save argument if OK */
1887 if (yield) sender_helo_name = string_copy_malloc(start);
1895 /*************************************************
1896 * Extract SMTP command option *
1897 *************************************************/
1899 /* This function picks the next option setting off the end of smtp_cmd_data. It
1900 is called for MAIL FROM and RCPT TO commands, to pick off the optional ESMTP
1901 things that can appear there.
1904 name point this at the name
1905 value point this at the data string
1907 Returns: TRUE if found an option
1911 extract_option(uschar **name, uschar **value)
1914 uschar *v = smtp_cmd_data + Ustrlen(smtp_cmd_data) - 1;
1915 while (isspace(*v)) v--;
1917 while (v > smtp_cmd_data && *v != '=' && !isspace(*v))
1919 /* Take care to not stop at a space embedded in a quoted local-part */
1921 if (*v == '"') do v--; while (*v != '"' && v > smtp_cmd_data+1);
1928 while(isalpha(n[-1])) n--;
1929 /* RFC says SP, but TAB seen in wild and other major MTAs accept it */
1930 if (!isspace(n[-1])) return FALSE;
1936 if (v == smtp_cmd_data) return FALSE;
1948 /*************************************************
1949 * Reset for new message *
1950 *************************************************/
1952 /* This function is called whenever the SMTP session is reset from
1953 within either of the setup functions.
1955 Argument: the stacking pool storage reset point
1960 smtp_reset(void *reset_point)
1962 recipients_list = NULL;
1963 rcpt_count = rcpt_defer_count = rcpt_fail_count =
1964 raw_recipients_count = recipients_count = recipients_list_max = 0;
1965 message_linecount = 0;
1967 acl_added_headers = NULL;
1968 acl_removed_headers = NULL;
1969 queue_only_policy = FALSE;
1970 rcpt_smtp_response = NULL;
1971 rcpt_smtp_response_same = TRUE;
1972 rcpt_in_progress = FALSE;
1973 deliver_freeze = FALSE; /* Can be set by ACL */
1974 freeze_tell = freeze_tell_config; /* Can be set by ACL */
1975 fake_response = OK; /* Can be set by ACL */
1976 #ifdef WITH_CONTENT_SCAN
1977 no_mbox_unspool = FALSE; /* Can be set by ACL */
1979 submission_mode = FALSE; /* Can be set by ACL */
1980 suppress_local_fixups = suppress_local_fixups_default; /* Can be set by ACL */
1981 active_local_from_check = local_from_check; /* Can be set by ACL */
1982 active_local_sender_retain = local_sender_retain; /* Can be set by ACL */
1983 sending_ip_address = NULL;
1984 return_path = sender_address = NULL;
1985 sender_data = NULL; /* Can be set by ACL */
1986 deliver_localpart_orig = NULL;
1987 deliver_domain_orig = NULL;
1988 callout_address = NULL;
1989 submission_name = NULL; /* Can be set by ACL */
1990 raw_sender = NULL; /* After SMTP rewrite, before qualifying */
1991 sender_address_unrewritten = NULL; /* Set only after verify rewrite */
1992 sender_verified_list = NULL; /* No senders verified */
1993 memset(sender_address_cache, 0, sizeof(sender_address_cache));
1994 memset(sender_domain_cache, 0, sizeof(sender_domain_cache));
1996 authenticated_sender = NULL;
1997 #ifdef EXPERIMENTAL_BRIGHTMAIL
1999 bmi_verdicts = NULL;
2001 dnslist_domain = dnslist_matched = NULL;
2002 #ifndef DISABLE_DKIM
2003 dkim_signers = NULL;
2004 dkim_disable_verify = FALSE;
2005 dkim_collect_input = FALSE;
2009 deliver_host = deliver_host_address = NULL; /* Can be set by ACL */
2010 #ifndef DISABLE_PRDR
2011 prdr_requested = FALSE;
2013 #ifdef EXPERIMENTAL_SPF
2014 spf_header_comment = NULL;
2015 spf_received = NULL;
2017 spf_smtp_comment = NULL;
2020 message_smtputf8 = FALSE;
2022 body_linecount = body_zerocount = 0;
2024 sender_rate = sender_rate_limit = sender_rate_period = NULL;
2025 ratelimiters_mail = NULL; /* Updated by ratelimit ACL condition */
2026 /* Note that ratelimiters_conn persists across resets. */
2028 /* Reset message ACL variables */
2032 /* The message body variables use malloc store. They may be set if this is
2033 not the first message in an SMTP session and the previous message caused them
2034 to be referenced in an ACL. */
2038 store_free(message_body);
2039 message_body = NULL;
2042 if (message_body_end)
2044 store_free(message_body_end);
2045 message_body_end = NULL;
2048 /* Warning log messages are also saved in malloc store. They are saved to avoid
2049 repetition in the same message, but it seems right to repeat them for different
2052 while (acl_warn_logged)
2054 string_item *this = acl_warn_logged;
2055 acl_warn_logged = acl_warn_logged->next;
2058 store_reset(reset_point);
2065 /*************************************************
2066 * Initialize for incoming batched SMTP message *
2067 *************************************************/
2069 /* This function is called from smtp_setup_msg() in the case when
2070 smtp_batched_input is true. This happens when -bS is used to pass a whole batch
2071 of messages in one file with SMTP commands between them. All errors must be
2072 reported by sending a message, and only MAIL FROM, RCPT TO, and DATA are
2073 relevant. After an error on a sender, or an invalid recipient, the remainder
2074 of the message is skipped. The value of received_protocol is already set.
2077 Returns: > 0 message successfully started (reached DATA)
2078 = 0 QUIT read or end of file reached
2079 < 0 should not occur
2083 smtp_setup_batch_msg(void)
2086 void *reset_point = store_get(0);
2088 /* Save the line count at the start of each transaction - single commands
2089 like HELO and RSET count as whole transactions. */
2091 bsmtp_transaction_linecount = receive_linecount;
2093 if ((receive_feof)()) return 0; /* Treat EOF as QUIT */
2095 cancel_cutthrough_connection(TRUE, US"smtp_setup_batch_msg");
2096 smtp_reset(reset_point); /* Reset for start of message */
2098 /* Deal with SMTP commands. This loop is exited by setting done to a POSITIVE
2099 value. The values are 2 larger than the required yield of the function. */
2104 uschar *recipient = NULL;
2105 int start, end, sender_domain, recipient_domain;
2107 switch(smtp_read_command(FALSE, GETC_BUFFER_UNLIMITED))
2109 /* The HELO/EHLO commands set sender_address_helo if they have
2110 valid data; otherwise they are ignored, except that they do
2111 a reset of the state. */
2116 check_helo(smtp_cmd_data);
2120 cancel_cutthrough_connection(TRUE, US"RSET received");
2121 smtp_reset(reset_point);
2122 bsmtp_transaction_linecount = receive_linecount;
2126 /* The MAIL FROM command requires an address as an operand. All we
2127 do here is to parse it for syntactic correctness. The form "<>" is
2128 a special case which converts into an empty string. The start/end
2129 pointers in the original are not used further for this address, as
2130 it is the canonical extracted address which is all that is kept. */
2133 smtp_mailcmd_count++; /* Count for no-mail log */
2134 if (sender_address != NULL)
2135 /* The function moan_smtp_batch() does not return. */
2136 moan_smtp_batch(smtp_cmd_buffer, "503 Sender already given");
2138 if (smtp_cmd_data[0] == 0)
2139 /* The function moan_smtp_batch() does not return. */
2140 moan_smtp_batch(smtp_cmd_buffer, "501 MAIL FROM must have an address operand");
2142 /* Reset to start of message */
2144 cancel_cutthrough_connection(TRUE, US"MAIL received");
2145 smtp_reset(reset_point);
2147 /* Apply SMTP rewrite */
2149 raw_sender = ((rewrite_existflags & rewrite_smtp) != 0)?
2150 rewrite_one(smtp_cmd_data, rewrite_smtp|rewrite_smtp_sender, NULL, FALSE,
2151 US"", global_rewrite_rules) : smtp_cmd_data;
2153 /* Extract the address; the TRUE flag allows <> as valid */
2156 parse_extract_address(raw_sender, &errmess, &start, &end, &sender_domain,
2159 if (raw_sender == NULL)
2160 /* The function moan_smtp_batch() does not return. */
2161 moan_smtp_batch(smtp_cmd_buffer, "501 %s", errmess);
2163 sender_address = string_copy(raw_sender);
2165 /* Qualify unqualified sender addresses if permitted to do so. */
2167 if (sender_domain == 0 && sender_address[0] != 0 && sender_address[0] != '@')
2169 if (allow_unqualified_sender)
2171 sender_address = rewrite_address_qualify(sender_address, FALSE);
2172 DEBUG(D_receive) debug_printf("unqualified address %s accepted "
2173 "and rewritten\n", raw_sender);
2175 /* The function moan_smtp_batch() does not return. */
2176 else moan_smtp_batch(smtp_cmd_buffer, "501 sender address must contain "
2182 /* The RCPT TO command requires an address as an operand. All we do
2183 here is to parse it for syntactic correctness. There may be any number
2184 of RCPT TO commands, specifying multiple senders. We build them all into
2185 a data structure that is in argc/argv format. The start/end values
2186 given by parse_extract_address are not used, as we keep only the
2187 extracted address. */
2190 if (sender_address == NULL)
2191 /* The function moan_smtp_batch() does not return. */
2192 moan_smtp_batch(smtp_cmd_buffer, "503 No sender yet given");
2194 if (smtp_cmd_data[0] == 0)
2195 /* The function moan_smtp_batch() does not return. */
2196 moan_smtp_batch(smtp_cmd_buffer, "501 RCPT TO must have an address operand");
2198 /* Check maximum number allowed */
2200 if (recipients_max > 0 && recipients_count + 1 > recipients_max)
2201 /* The function moan_smtp_batch() does not return. */
2202 moan_smtp_batch(smtp_cmd_buffer, "%s too many recipients",
2203 recipients_max_reject? "552": "452");
2205 /* Apply SMTP rewrite, then extract address. Don't allow "<>" as a
2206 recipient address */
2208 recipient = rewrite_existflags & rewrite_smtp
2209 ? rewrite_one(smtp_cmd_data, rewrite_smtp, NULL, FALSE, US"",
2210 global_rewrite_rules)
2213 recipient = parse_extract_address(recipient, &errmess, &start, &end,
2214 &recipient_domain, FALSE);
2217 /* The function moan_smtp_batch() does not return. */
2218 moan_smtp_batch(smtp_cmd_buffer, "501 %s", errmess);
2220 /* If the recipient address is unqualified, qualify it if permitted. Then
2221 add it to the list of recipients. */
2223 if (recipient_domain == 0)
2225 if (allow_unqualified_recipient)
2227 DEBUG(D_receive) debug_printf("unqualified address %s accepted\n",
2229 recipient = rewrite_address_qualify(recipient, TRUE);
2231 /* The function moan_smtp_batch() does not return. */
2232 else moan_smtp_batch(smtp_cmd_buffer, "501 recipient address must contain "
2235 receive_add_recipient(recipient, -1);
2239 /* The DATA command is legal only if it follows successful MAIL FROM
2240 and RCPT TO commands. This function is complete when a valid DATA
2241 command is encountered. */
2244 if (sender_address == NULL || recipients_count <= 0)
2246 /* The function moan_smtp_batch() does not return. */
2247 if (sender_address == NULL)
2248 moan_smtp_batch(smtp_cmd_buffer,
2249 "503 MAIL FROM:<sender> command must precede DATA");
2251 moan_smtp_batch(smtp_cmd_buffer,
2252 "503 RCPT TO:<recipient> must precede DATA");
2256 done = 3; /* DATA successfully achieved */
2257 message_ended = END_NOTENDED; /* Indicate in middle of message */
2262 /* The VRFY, EXPN, HELP, ETRN, and NOOP commands are ignored. */
2269 bsmtp_transaction_linecount = receive_linecount;
2280 /* The function moan_smtp_batch() does not return. */
2281 moan_smtp_batch(smtp_cmd_buffer, "501 Unexpected argument data");
2286 /* The function moan_smtp_batch() does not return. */
2287 moan_smtp_batch(smtp_cmd_buffer, "501 Unexpected NULL in SMTP command");
2292 /* The function moan_smtp_batch() does not return. */
2293 moan_smtp_batch(smtp_cmd_buffer, "500 Command unrecognized");
2298 return done - 2; /* Convert yield values */
2305 smtp_log_tls_fail(uschar * errstr)
2307 uschar * conn_info = smtp_get_connection_info();
2309 if (Ustrncmp(conn_info, US"SMTP ", 5) == 0) conn_info += 5;
2310 /* I'd like to get separated H= here, but too hard for now */
2312 log_write(0, LOG_MAIN, "TLS error on %s %s", conn_info, errstr);
2324 struct tcp_info tinfo;
2325 socklen_t len = sizeof(tinfo);
2327 if ( getsockopt(fileno(smtp_out), IPPROTO_TCP, TCP_INFO, &tinfo, &len) == 0
2328 && tinfo.tcpi_state == TCP_SYN_RECV
2331 DEBUG(D_receive) debug_printf("TCP_FASTOPEN mode connection (state TCP_SYN_RECV)\n");
2332 tcp_in_fastopen = TRUE;
2339 /*************************************************
2340 * Start an SMTP session *
2341 *************************************************/
2343 /* This function is called at the start of an SMTP session. Thereafter,
2344 smtp_setup_msg() is called to initiate each separate message. This
2345 function does host-specific testing, and outputs the banner line.
2348 Returns: FALSE if the session can not continue; something has
2349 gone wrong, or the connection to the host is blocked
2353 smtp_start_session(void)
2356 uschar *user_msg, *log_msg;
2361 gettimeofday(&smtp_connection_start, NULL);
2362 for (smtp_ch_index = 0; smtp_ch_index < SMTP_HBUFF_SIZE; smtp_ch_index++)
2363 smtp_connection_had[smtp_ch_index] = SCH_NONE;
2366 /* Default values for certain variables */
2368 helo_seen = esmtp = helo_accept_junk = FALSE;
2369 smtp_mailcmd_count = 0;
2370 count_nonmail = TRUE_UNSET;
2371 synprot_error_count = unknown_command_count = nonmail_command_count = 0;
2372 smtp_delay_mail = smtp_rlm_base;
2373 auth_advertised = FALSE;
2374 pipelining_advertised = FALSE;
2375 pipelining_enable = TRUE;
2376 sync_cmd_limit = NON_SYNC_CMD_NON_PIPELINING;
2377 smtp_exit_function_called = FALSE; /* For avoiding loop in not-quit exit */
2379 /* If receiving by -bs from a trusted user, or testing with -bh, we allow
2380 authentication settings from -oMaa to remain in force. */
2382 if (!host_checking && !sender_host_notsocket) sender_host_authenticated = NULL;
2383 authenticated_by = NULL;
2386 tls_in.cipher = tls_in.peerdn = NULL;
2387 tls_in.ourcert = tls_in.peercert = NULL;
2389 tls_in.ocsp = OCSP_NOT_REQ;
2390 tls_advertised = FALSE;
2392 dsn_advertised = FALSE;
2394 smtputf8_advertised = FALSE;
2397 /* Reset ACL connection variables */
2401 /* Allow for trailing 0 in the command and data buffers. */
2403 if (!(smtp_cmd_buffer = US malloc(2*SMTP_CMD_BUFFER_SIZE + 2)))
2404 log_write(0, LOG_MAIN|LOG_PANIC_DIE,
2405 "malloc() failed for SMTP command buffer");
2407 smtp_cmd_buffer[0] = 0;
2408 smtp_data_buffer = smtp_cmd_buffer + SMTP_CMD_BUFFER_SIZE + 1;
2410 /* For batched input, the protocol setting can be overridden from the
2411 command line by a trusted caller. */
2413 if (smtp_batched_input)
2415 if (!received_protocol) received_protocol = US"local-bsmtp";
2418 /* For non-batched SMTP input, the protocol setting is forced here. It will be
2419 reset later if any of EHLO/AUTH/STARTTLS are received. */
2423 (sender_host_address ? protocols : protocols_local) [pnormal];
2425 /* Set up the buffer for inputting using direct read() calls, and arrange to
2426 call the local functions instead of the standard C ones. */
2428 if (!(smtp_inbuffer = US malloc(IN_BUFFER_SIZE)))
2429 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "malloc() failed for SMTP input buffer");
2431 receive_getc = smtp_getc;
2432 receive_getbuf = smtp_getbuf;
2433 receive_get_cache = smtp_get_cache;
2434 receive_ungetc = smtp_ungetc;
2435 receive_feof = smtp_feof;
2436 receive_ferror = smtp_ferror;
2437 receive_smtp_buffered = smtp_buffered;
2438 smtp_inptr = smtp_inend = smtp_inbuffer;
2439 smtp_had_eof = smtp_had_error = 0;
2441 /* Set up the message size limit; this may be host-specific */
2443 thismessage_size_limit = expand_string_integer(message_size_limit, TRUE);
2444 if (expand_string_message != NULL)
2446 if (thismessage_size_limit == -1)
2447 log_write(0, LOG_MAIN|LOG_PANIC, "unable to expand message_size_limit: "
2448 "%s", expand_string_message);
2450 log_write(0, LOG_MAIN|LOG_PANIC, "invalid message_size_limit: "
2451 "%s", expand_string_message);
2452 smtp_closedown(US"Temporary local problem - please try later");
2456 /* When a message is input locally via the -bs or -bS options, sender_host_
2457 unknown is set unless -oMa was used to force an IP address, in which case it
2458 is checked like a real remote connection. When -bs is used from inetd, this
2459 flag is not set, causing the sending host to be checked. The code that deals
2460 with IP source routing (if configured) is never required for -bs or -bS and
2461 the flag sender_host_notsocket is used to suppress it.
2463 If smtp_accept_max and smtp_accept_reserve are set, keep some connections in
2464 reserve for certain hosts and/or networks. */
2466 if (!sender_host_unknown)
2469 BOOL reserved_host = FALSE;
2471 /* Look up IP options (source routing info) on the socket if this is not an
2472 -oMa "host", and if any are found, log them and drop the connection.
2474 Linux (and others now, see below) is different to everyone else, so there
2475 has to be some conditional compilation here. Versions of Linux before 2.1.15
2476 used a structure whose name was "options". Somebody finally realized that
2477 this name was silly, and it got changed to "ip_options". I use the
2478 newer name here, but there is a fudge in the script that sets up os.h
2479 to define a macro in older Linux systems.
2481 Sigh. Linux is a fast-moving target. Another generation of Linux uses
2482 glibc 2, which has chosen ip_opts for the structure name. This is now
2483 really a glibc thing rather than a Linux thing, so the condition name
2484 has been changed to reflect this. It is relevant also to GNU/Hurd.
2486 Mac OS 10.x (Darwin) is like the later glibc versions, but without the
2487 setting of the __GLIBC__ macro, so we can't detect it automatically. There's
2488 a special macro defined in the os.h file.
2490 Some DGUX versions on older hardware appear not to support IP options at
2491 all, so there is now a general macro which can be set to cut out this
2494 How to do this properly in IPv6 is not yet known. */
2496 #if !HAVE_IPV6 && !defined(NO_IP_OPTIONS)
2498 #ifdef GLIBC_IP_OPTIONS
2499 #if (!defined __GLIBC__) || (__GLIBC__ < 2)
2504 #elif defined DARWIN_IP_OPTIONS
2510 if (!host_checking && !sender_host_notsocket)
2513 EXIM_SOCKLEN_T optlen = sizeof(struct ip_options) + MAX_IPOPTLEN;
2514 struct ip_options *ipopt = store_get(optlen);
2516 struct ip_opts ipoptblock;
2517 struct ip_opts *ipopt = &ipoptblock;
2518 EXIM_SOCKLEN_T optlen = sizeof(ipoptblock);
2520 struct ipoption ipoptblock;
2521 struct ipoption *ipopt = &ipoptblock;
2522 EXIM_SOCKLEN_T optlen = sizeof(ipoptblock);
2525 /* Occasional genuine failures of getsockopt() have been seen - for
2526 example, "reset by peer". Therefore, just log and give up on this
2527 call, unless the error is ENOPROTOOPT. This error is given by systems
2528 that have the interfaces but not the mechanism - e.g. GNU/Hurd at the time
2529 of writing. So for that error, carry on - we just can't do an IP options
2532 DEBUG(D_receive) debug_printf("checking for IP options\n");
2534 if (getsockopt(fileno(smtp_out), IPPROTO_IP, IP_OPTIONS, US (ipopt),
2537 if (errno != ENOPROTOOPT)
2539 log_write(0, LOG_MAIN, "getsockopt() failed from %s: %s",
2540 host_and_ident(FALSE), strerror(errno));
2541 smtp_printf("451 SMTP service not available\r\n", FALSE);
2546 /* Deal with any IP options that are set. On the systems I have looked at,
2547 the value of MAX_IPOPTLEN has been 40, meaning that there should never be
2548 more logging data than will fit in big_buffer. Nevertheless, after somebody
2549 questioned this code, I've added in some paranoid checking. */
2551 else if (optlen > 0)
2553 uschar *p = big_buffer;
2554 uschar *pend = big_buffer + big_buffer_size;
2555 uschar *opt, *adptr;
2557 struct in_addr addr;
2560 uschar *optstart = US (ipopt->__data);
2562 uschar *optstart = US (ipopt->ip_opts);
2564 uschar *optstart = US (ipopt->ipopt_list);
2567 DEBUG(D_receive) debug_printf("IP options exist\n");
2569 Ustrcpy(p, "IP options on incoming call:");
2572 for (opt = optstart; opt != NULL &&
2573 opt < US (ipopt) + optlen;)
2587 if (!string_format(p, pend-p, " %s [@%s",
2588 (*opt == IPOPT_SSRR)? "SSRR" : "LSRR",
2590 inet_ntoa(*((struct in_addr *)(&(ipopt->faddr))))))
2592 inet_ntoa(ipopt->ip_dst)))
2594 inet_ntoa(ipopt->ipopt_dst)))
2602 optcount = (opt[1] - 3) / sizeof(struct in_addr);
2604 while (optcount-- > 0)
2606 memcpy(&addr, adptr, sizeof(addr));
2607 if (!string_format(p, pend - p - 1, "%s%s",
2608 (optcount == 0)? ":" : "@", inet_ntoa(addr)))
2614 adptr += sizeof(struct in_addr);
2623 if (pend - p < 4 + 3*opt[1]) { opt = NULL; break; }
2626 for (i = 0; i < opt[1]; i++)
2627 p += sprintf(CS p, "%2.2x ", opt[i]);
2636 log_write(0, LOG_MAIN, "%s", big_buffer);
2638 /* Refuse any call with IP options. This is what tcpwrappers 7.5 does. */
2640 log_write(0, LOG_MAIN|LOG_REJECT,
2641 "connection from %s refused (IP options)", host_and_ident(FALSE));
2643 smtp_printf("554 SMTP service not available\r\n", FALSE);
2647 /* Length of options = 0 => there are no options */
2649 else DEBUG(D_receive) debug_printf("no IP options found\n");
2651 #endif /* HAVE_IPV6 && !defined(NO_IP_OPTIONS) */
2653 /* Set keep-alive in socket options. The option is on by default. This
2654 setting is an attempt to get rid of some hanging connections that stick in
2655 read() when the remote end (usually a dialup) goes away. */
2657 if (smtp_accept_keepalive && !sender_host_notsocket)
2658 ip_keepalive(fileno(smtp_out), sender_host_address, FALSE);
2660 /* If the current host matches host_lookup, set the name by doing a
2661 reverse lookup. On failure, sender_host_name will be NULL and
2662 host_lookup_failed will be TRUE. This may or may not be serious - optional
2665 if (verify_check_host(&host_lookup) == OK)
2667 (void)host_name_lookup();
2668 host_build_sender_fullhost();
2671 /* Delay this until we have the full name, if it is looked up. */
2673 set_process_info("handling incoming connection from %s",
2674 host_and_ident(FALSE));
2676 /* Expand smtp_receive_timeout, if needed */
2678 if (smtp_receive_timeout_s)
2681 if ( !(exp = expand_string(smtp_receive_timeout_s))
2683 || (smtp_receive_timeout = readconf_readtime(exp, 0, FALSE)) < 0
2685 log_write(0, LOG_MAIN|LOG_PANIC,
2686 "bad value for smtp_receive_timeout: '%s'", exp ? exp : US"");
2689 /* Test for explicit connection rejection */
2691 if (verify_check_host(&host_reject_connection) == OK)
2693 log_write(L_connection_reject, LOG_MAIN|LOG_REJECT, "refused connection "
2694 "from %s (host_reject_connection)", host_and_ident(FALSE));
2695 smtp_printf("554 SMTP service not available\r\n", FALSE);
2699 /* Test with TCP Wrappers if so configured. There is a problem in that
2700 hosts_ctl() returns 0 (deny) under a number of system failure circumstances,
2701 such as disks dying. In these cases, it is desirable to reject with a 4xx
2702 error instead of a 5xx error. There isn't a "right" way to detect such
2703 problems. The following kludge is used: errno is zeroed before calling
2704 hosts_ctl(). If the result is "reject", a 5xx error is given only if the
2705 value of errno is 0 or ENOENT (which happens if /etc/hosts.{allow,deny} does
2708 #ifdef USE_TCP_WRAPPERS
2710 if (!(tcp_wrappers_name = expand_string(tcp_wrappers_daemon_name)))
2711 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "Expansion of \"%s\" "
2712 "(tcp_wrappers_name) failed: %s", string_printing(tcp_wrappers_name),
2713 expand_string_message);
2715 if (!hosts_ctl(tcp_wrappers_name,
2716 sender_host_name ? CS sender_host_name : STRING_UNKNOWN,
2717 sender_host_address ? CS sender_host_address : STRING_UNKNOWN,
2718 sender_ident ? CS sender_ident : STRING_UNKNOWN))
2720 if (errno == 0 || errno == ENOENT)
2722 HDEBUG(D_receive) debug_printf("tcp wrappers rejection\n");
2723 log_write(L_connection_reject,
2724 LOG_MAIN|LOG_REJECT, "refused connection from %s "
2725 "(tcp wrappers)", host_and_ident(FALSE));
2726 smtp_printf("554 SMTP service not available\r\n", FALSE);
2730 int save_errno = errno;
2731 HDEBUG(D_receive) debug_printf("tcp wrappers rejected with unexpected "
2732 "errno value %d\n", save_errno);
2733 log_write(L_connection_reject,
2734 LOG_MAIN|LOG_REJECT, "temporarily refused connection from %s "
2735 "(tcp wrappers errno=%d)", host_and_ident(FALSE), save_errno);
2736 smtp_printf("451 Temporary local problem - please try later\r\n", FALSE);
2742 /* Check for reserved slots. The value of smtp_accept_count has already been
2743 incremented to include this process. */
2745 if (smtp_accept_max > 0 &&
2746 smtp_accept_count > smtp_accept_max - smtp_accept_reserve)
2748 if ((rc = verify_check_host(&smtp_reserve_hosts)) != OK)
2750 log_write(L_connection_reject,
2751 LOG_MAIN, "temporarily refused connection from %s: not in "
2752 "reserve list: connected=%d max=%d reserve=%d%s",
2753 host_and_ident(FALSE), smtp_accept_count - 1, smtp_accept_max,
2754 smtp_accept_reserve, (rc == DEFER)? " (lookup deferred)" : "");
2755 smtp_printf("421 %s: Too many concurrent SMTP connections; "
2756 "please try again later\r\n", FALSE, smtp_active_hostname);
2759 reserved_host = TRUE;
2762 /* If a load level above which only messages from reserved hosts are
2763 accepted is set, check the load. For incoming calls via the daemon, the
2764 check is done in the superior process if there are no reserved hosts, to
2765 save a fork. In all cases, the load average will already be available
2766 in a global variable at this point. */
2768 if (smtp_load_reserve >= 0 &&
2769 load_average > smtp_load_reserve &&
2771 verify_check_host(&smtp_reserve_hosts) != OK)
2773 log_write(L_connection_reject,
2774 LOG_MAIN, "temporarily refused connection from %s: not in "
2775 "reserve list and load average = %.2f", host_and_ident(FALSE),
2776 (double)load_average/1000.0);
2777 smtp_printf("421 %s: Too much load; please try again later\r\n", FALSE,
2778 smtp_active_hostname);
2782 /* Determine whether unqualified senders or recipients are permitted
2783 for this host. Unfortunately, we have to do this every time, in order to
2784 set the flags so that they can be inspected when considering qualifying
2785 addresses in the headers. For a site that permits no qualification, this
2786 won't take long, however. */
2788 allow_unqualified_sender =
2789 verify_check_host(&sender_unqualified_hosts) == OK;
2791 allow_unqualified_recipient =
2792 verify_check_host(&recipient_unqualified_hosts) == OK;
2794 /* Determine whether HELO/EHLO is required for this host. The requirement
2795 can be hard or soft. */
2797 helo_required = verify_check_host(&helo_verify_hosts) == OK;
2799 helo_verify = verify_check_host(&helo_try_verify_hosts) == OK;
2801 /* Determine whether this hosts is permitted to send syntactic junk
2802 after a HELO or EHLO command. */
2804 helo_accept_junk = verify_check_host(&helo_accept_junk_hosts) == OK;
2807 /* For batch SMTP input we are now done. */
2809 if (smtp_batched_input) return TRUE;
2811 /* If valid Proxy Protocol source is connecting, set up session.
2812 * Failure will not allow any SMTP function other than QUIT. */
2814 #ifdef SUPPORT_PROXY
2815 proxy_session = FALSE;
2816 proxy_session_failed = FALSE;
2817 if (check_proxy_protocol_host())
2818 setup_proxy_protocol_host();
2821 /* Start up TLS if tls_on_connect is set. This is for supporting the legacy
2822 smtps port for use with older style SSL MTAs. */
2825 if (tls_in.on_connect && tls_server_start(tls_require_ciphers, &user_msg) != OK)
2826 return smtp_log_tls_fail(user_msg);
2829 /* Run the connect ACL if it exists */
2832 if (acl_smtp_connect)
2835 if ((rc = acl_check(ACL_WHERE_CONNECT, NULL, acl_smtp_connect, &user_msg,
2838 (void) smtp_handle_acl_fail(ACL_WHERE_CONNECT, rc, user_msg, log_msg);
2843 /* Output the initial message for a two-way SMTP connection. It may contain
2844 newlines, which then cause a multi-line response to be given. */
2846 code = US"220"; /* Default status code */
2847 esc = US""; /* Default extended status code */
2848 esclen = 0; /* Length of esc */
2852 if (!(s = expand_string(smtp_banner)))
2853 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "Expansion of \"%s\" (smtp_banner) "
2854 "failed: %s", smtp_banner, expand_string_message);
2860 smtp_message_code(&code, &codelen, &s, NULL, TRUE);
2864 esclen = codelen - 4;
2868 /* Remove any terminating newlines; might as well remove trailing space too */
2871 while (p > s && isspace(p[-1])) p--;
2874 /* It seems that CC:Mail is braindead, and assumes that the greeting message
2875 is all contained in a single IP packet. The original code wrote out the
2876 greeting using several calls to fprint/fputc, and on busy servers this could
2877 cause it to be split over more than one packet - which caused CC:Mail to fall
2878 over when it got the second part of the greeting after sending its first
2879 command. Sigh. To try to avoid this, build the complete greeting message
2880 first, and output it in one fell swoop. This gives a better chance of it
2881 ending up as a single packet. */
2883 ss = string_get(256);
2886 do /* At least once, in case we have an empty string */
2889 uschar *linebreak = Ustrchr(p, '\n');
2890 ss = string_catn(ss, code, 3);
2891 if (linebreak == NULL)
2894 ss = string_catn(ss, US" ", 1);
2898 len = linebreak - p;
2899 ss = string_catn(ss, US"-", 1);
2901 ss = string_catn(ss, esc, esclen);
2902 ss = string_catn(ss, p, len);
2903 ss = string_catn(ss, US"\r\n", 2);
2905 if (linebreak != NULL) p++;
2909 /* Before we write the banner, check that there is no input pending, unless
2910 this synchronisation check is disabled. */
2914 unsigned n = smtp_inend - smtp_inptr;
2917 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP protocol "
2918 "synchronization error (input sent without waiting for greeting): "
2919 "rejected connection from %s input=\"%s\"", host_and_ident(TRUE),
2920 string_printing(string_copyn(smtp_inptr, n)));
2921 smtp_printf("554 SMTP synchronization error\r\n", FALSE);
2925 /* Now output the banner */
2927 smtp_printf("%s", FALSE, string_from_gstring(ss));
2929 /* Attempt to see if we sent the banner before the last ACK of the 3-way
2930 handshake arrived. If so we must have managed a TFO. */
2943 /*************************************************
2944 * Handle SMTP syntax and protocol errors *
2945 *************************************************/
2947 /* Write to the log for SMTP syntax errors in incoming commands, if configured
2948 to do so. Then transmit the error response. The return value depends on the
2949 number of syntax and protocol errors in this SMTP session.
2952 type error type, given as a log flag bit
2953 code response code; <= 0 means don't send a response
2954 data data to reflect in the response (can be NULL)
2955 errmess the error message
2957 Returns: -1 limit of syntax/protocol errors NOT exceeded
2958 +1 limit of syntax/protocol errors IS exceeded
2960 These values fit in with the values of the "done" variable in the main
2961 processing loop in smtp_setup_msg(). */
2964 synprot_error(int type, int code, uschar *data, uschar *errmess)
2968 log_write(type, LOG_MAIN, "SMTP %s error in \"%s\" %s %s",
2969 (type == L_smtp_syntax_error)? "syntax" : "protocol",
2970 string_printing(smtp_cmd_buffer), host_and_ident(TRUE), errmess);
2972 if (++synprot_error_count > smtp_max_synprot_errors)
2975 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
2976 "syntax or protocol errors (last command was \"%s\")",
2977 host_and_ident(FALSE), string_printing(smtp_cmd_buffer));
2982 smtp_printf("%d%c%s%s%s\r\n", FALSE, code, yield == 1 ? '-' : ' ',
2983 data ? data : US"", data ? US": " : US"", errmess);
2985 smtp_printf("%d Too many syntax or protocol errors\r\n", FALSE, code);
2994 /*************************************************
2995 * Send SMTP response, possibly multiline *
2996 *************************************************/
2998 /* There are, it seems, broken clients out there that cannot handle multiline
2999 responses. If no_multiline_responses is TRUE (it can be set from an ACL), we
3000 output nothing for non-final calls, and only the first line for anything else.
3003 code SMTP code, may involve extended status codes
3004 codelen length of smtp code; if > 4 there's an ESC
3005 final FALSE if the last line isn't the final line
3006 msg message text, possibly containing newlines
3012 smtp_respond(uschar* code, int codelen, BOOL final, uschar *msg)
3017 if (!final && no_multiline_responses) return;
3022 esclen = codelen - 4;
3025 /* If this is the first output for a (non-batch) RCPT command, see if all RCPTs
3026 have had the same. Note: this code is also present in smtp_printf(). It would
3027 be tidier to have it only in one place, but when it was added, it was easier to
3028 do it that way, so as not to have to mess with the code for the RCPT command,
3029 which sometimes uses smtp_printf() and sometimes smtp_respond(). */
3031 if (rcpt_in_progress)
3033 if (rcpt_smtp_response == NULL)
3034 rcpt_smtp_response = string_copy(msg);
3035 else if (rcpt_smtp_response_same &&
3036 Ustrcmp(rcpt_smtp_response, msg) != 0)
3037 rcpt_smtp_response_same = FALSE;
3038 rcpt_in_progress = FALSE;
3041 /* Now output the message, splitting it up into multiple lines if necessary.
3042 We only handle pipelining these responses as far as nonfinal/final groups,
3043 not the whole MAIL/RCPT/DATA response set. */
3047 uschar *nl = Ustrchr(msg, '\n');
3050 smtp_printf("%.3s%c%.*s%s\r\n", !final, code, final ? ' ':'-', esclen, esc, msg);
3053 else if (nl[1] == 0 || no_multiline_responses)
3055 smtp_printf("%.3s%c%.*s%.*s\r\n", !final, code, final ? ' ':'-', esclen, esc,
3056 (int)(nl - msg), msg);
3061 smtp_printf("%.3s-%.*s%.*s\r\n", TRUE, code, esclen, esc, (int)(nl - msg), msg);
3063 while (isspace(*msg)) msg++;
3071 /*************************************************
3072 * Parse user SMTP message *
3073 *************************************************/
3075 /* This function allows for user messages overriding the response code details
3076 by providing a suitable response code string at the start of the message
3077 user_msg. Check the message for starting with a response code and optionally an
3078 extended status code. If found, check that the first digit is valid, and if so,
3079 change the code pointer and length to use the replacement. An invalid code
3080 causes a panic log; in this case, if the log messages is the same as the user
3081 message, we must also adjust the value of the log message to show the code that
3082 is actually going to be used (the original one).
3084 This function is global because it is called from receive.c as well as within
3087 Note that the code length returned includes the terminating whitespace
3088 character, which is always included in the regex match.
3091 code SMTP code, may involve extended status codes
3092 codelen length of smtp code; if > 4 there's an ESC
3094 log_msg optional log message, to be adjusted with the new SMTP code
3095 check_valid if true, verify the response code
3101 smtp_message_code(uschar **code, int *codelen, uschar **msg, uschar **log_msg,
3107 if (!msg || !*msg) return;
3109 if ((n = pcre_exec(regex_smtp_code, NULL, CS *msg, Ustrlen(*msg), 0,
3110 PCRE_EOPT, ovector, sizeof(ovector)/sizeof(int))) < 0) return;
3112 if (check_valid && (*msg)[0] != (*code)[0])
3114 log_write(0, LOG_MAIN|LOG_PANIC, "configured error code starts with "
3115 "incorrect digit (expected %c) in \"%s\"", (*code)[0], *msg);
3116 if (log_msg != NULL && *log_msg == *msg)
3117 *log_msg = string_sprintf("%s %s", *code, *log_msg + ovector[1]);
3122 *codelen = ovector[1]; /* Includes final space */
3124 *msg += ovector[1]; /* Chop the code off the message */
3131 /*************************************************
3132 * Handle an ACL failure *
3133 *************************************************/
3135 /* This function is called when acl_check() fails. As well as calls from within
3136 this module, it is called from receive.c for an ACL after DATA. It sorts out
3137 logging the incident, and sets up the error response. A message containing
3138 newlines is turned into a multiline SMTP response, but for logging, only the
3141 There's a table of default permanent failure response codes to use in
3142 globals.c, along with the table of names. VFRY is special. Despite RFC1123 it
3143 defaults disabled in Exim. However, discussion in connection with RFC 821bis
3144 (aka RFC 2821) has concluded that the response should be 252 in the disabled
3145 state, because there are broken clients that try VRFY before RCPT. A 5xx
3146 response should be given only when the address is positively known to be
3147 undeliverable. Sigh. We return 252 if there is no VRFY ACL or it provides
3148 no explicit code, but if there is one we let it know best.
3149 Also, for ETRN, 458 is given on refusal, and for AUTH, 503.
3151 From Exim 4.63, it is possible to override the response code details by
3152 providing a suitable response code string at the start of the message provided
3153 in user_msg. The code's first digit is checked for validity.
3156 where where the ACL was called from
3158 user_msg a message that can be included in an SMTP response
3159 log_msg a message for logging
3161 Returns: 0 in most cases
3162 2 if the failure code was FAIL_DROP, in which case the
3163 SMTP connection should be dropped (this value fits with the
3164 "done" variable in smtp_setup_msg() below)
3168 smtp_handle_acl_fail(int where, int rc, uschar *user_msg, uschar *log_msg)
3170 BOOL drop = rc == FAIL_DROP;
3174 uschar *sender_info = US"";
3176 #ifdef WITH_CONTENT_SCAN
3177 where == ACL_WHERE_MIME ? US"during MIME ACL checks" :
3179 where == ACL_WHERE_PREDATA ? US"DATA" :
3180 where == ACL_WHERE_DATA ? US"after DATA" :
3181 #ifndef DISABLE_PRDR
3182 where == ACL_WHERE_PRDR ? US"after DATA PRDR" :
3185 string_sprintf("%s %s", acl_wherenames[where], smtp_cmd_data) :
3186 string_sprintf("%s in \"connect\" ACL", acl_wherenames[where]);
3188 if (drop) rc = FAIL;
3190 /* Set the default SMTP code, and allow a user message to change it. */
3192 smtp_code = rc == FAIL ? acl_wherecodes[where] : US"451";
3193 smtp_message_code(&smtp_code, &codelen, &user_msg, &log_msg,
3194 where != ACL_WHERE_VRFY);
3196 /* We used to have sender_address here; however, there was a bug that was not
3197 updating sender_address after a rewrite during a verify. When this bug was
3198 fixed, sender_address at this point became the rewritten address. I'm not sure
3199 this is what should be logged, so I've changed to logging the unrewritten
3200 address to retain backward compatibility. */
3202 #ifndef WITH_CONTENT_SCAN
3203 if (where == ACL_WHERE_RCPT || where == ACL_WHERE_DATA)
3205 if (where == ACL_WHERE_RCPT || where == ACL_WHERE_DATA || where == ACL_WHERE_MIME)
3208 sender_info = string_sprintf("F=<%s>%s%s%s%s ",
3209 sender_address_unrewritten ? sender_address_unrewritten : sender_address,
3210 sender_host_authenticated ? US" A=" : US"",
3211 sender_host_authenticated ? sender_host_authenticated : US"",
3212 sender_host_authenticated && authenticated_id ? US":" : US"",
3213 sender_host_authenticated && authenticated_id ? authenticated_id : US""
3217 /* If there's been a sender verification failure with a specific message, and
3218 we have not sent a response about it yet, do so now, as a preliminary line for
3219 failures, but not defers. However, always log it for defer, and log it for fail
3220 unless the sender_verify_fail log selector has been turned off. */
3222 if (sender_verified_failed &&
3223 !testflag(sender_verified_failed, af_sverify_told))
3225 BOOL save_rcpt_in_progress = rcpt_in_progress;
3226 rcpt_in_progress = FALSE; /* So as not to treat these as the error */
3228 setflag(sender_verified_failed, af_sverify_told);
3230 if (rc != FAIL || LOGGING(sender_verify_fail))
3231 log_write(0, LOG_MAIN|LOG_REJECT, "%s sender verify %s for <%s>%s",
3232 host_and_ident(TRUE),
3233 ((sender_verified_failed->special_action & 255) == DEFER)? "defer":"fail",
3234 sender_verified_failed->address,
3235 (sender_verified_failed->message == NULL)? US"" :
3236 string_sprintf(": %s", sender_verified_failed->message));
3238 if (rc == FAIL && sender_verified_failed->user_message)
3239 smtp_respond(smtp_code, codelen, FALSE, string_sprintf(
3240 testflag(sender_verified_failed, af_verify_pmfail)?
3241 "Postmaster verification failed while checking <%s>\n%s\n"
3242 "Several RFCs state that you are required to have a postmaster\n"
3243 "mailbox for each mail domain. This host does not accept mail\n"
3244 "from domains whose servers reject the postmaster address."
3246 testflag(sender_verified_failed, af_verify_nsfail)?
3247 "Callback setup failed while verifying <%s>\n%s\n"
3248 "The initial connection, or a HELO or MAIL FROM:<> command was\n"
3249 "rejected. Refusing MAIL FROM:<> does not help fight spam, disregards\n"
3250 "RFC requirements, and stops you from receiving standard bounce\n"
3251 "messages. This host does not accept mail from domains whose servers\n"
3254 "Verification failed for <%s>\n%s",
3255 sender_verified_failed->address,
3256 sender_verified_failed->user_message));
3258 rcpt_in_progress = save_rcpt_in_progress;
3261 /* Sort out text for logging */
3263 log_msg = log_msg ? string_sprintf(": %s", log_msg) : US"";
3264 if ((lognl = Ustrchr(log_msg, '\n'))) *lognl = 0;
3266 /* Send permanent failure response to the command, but the code used isn't
3267 always a 5xx one - see comments at the start of this function. If the original
3268 rc was FAIL_DROP we drop the connection and yield 2. */
3271 smtp_respond(smtp_code, codelen, TRUE,
3272 user_msg ? user_msg : US"Administrative prohibition");
3274 /* Send temporary failure response to the command. Don't give any details,
3275 unless acl_temp_details is set. This is TRUE for a callout defer, a "defer"
3276 verb, and for a header verify when smtp_return_error_details is set.
3278 This conditional logic is all somewhat of a mess because of the odd
3279 interactions between temp_details and return_error_details. One day it should
3280 be re-implemented in a tidier fashion. */
3283 if (acl_temp_details && user_msg)
3285 if ( smtp_return_error_details
3286 && sender_verified_failed
3287 && sender_verified_failed->message
3289 smtp_respond(smtp_code, codelen, FALSE, sender_verified_failed->message);
3291 smtp_respond(smtp_code, codelen, TRUE, user_msg);
3294 smtp_respond(smtp_code, codelen, TRUE,
3295 US"Temporary local problem - please try later");
3297 /* Log the incident to the logs that are specified by log_reject_target
3298 (default main, reject). This can be empty to suppress logging of rejections. If
3299 the connection is not forcibly to be dropped, return 0. Otherwise, log why it
3300 is closing if required and return 2. */
3302 if (log_reject_target != 0)
3305 gstring * g = s_tlslog(NULL);
3306 uschar * tls = string_from_gstring(g);
3307 if (!tls) tls = US"";
3309 uschar * tls = US"";
3311 log_write(where == ACL_WHERE_CONNECT ? L_connection_reject : 0,
3312 log_reject_target, "%s%s%s %s%srejected %s%s",
3313 LOGGING(dnssec) && sender_host_dnssec ? US" DS" : US"",
3314 host_and_ident(TRUE),
3317 rc == FAIL ? US"" : US"temporarily ",
3321 if (!drop) return 0;
3323 log_write(L_smtp_connection, LOG_MAIN, "%s closed by DROP in ACL",
3324 smtp_get_connection_info());
3326 /* Run the not-quit ACL, but without any custom messages. This should not be a
3327 problem, because we get here only if some other ACL has issued "drop", and
3328 in that case, *its* custom messages will have been used above. */
3330 smtp_notquit_exit(US"acl-drop", NULL, NULL);
3337 /*************************************************
3338 * Handle SMTP exit when QUIT is not given *
3339 *************************************************/
3341 /* This function provides a logging/statistics hook for when an SMTP connection
3342 is dropped on the floor or the other end goes away. It's a global function
3343 because it's called from receive.c as well as this module. As well as running
3344 the NOTQUIT ACL, if there is one, this function also outputs a final SMTP
3345 response, either with a custom message from the ACL, or using a default. There
3346 is one case, however, when no message is output - after "drop". In that case,
3347 the ACL that obeyed "drop" has already supplied the custom message, and NULL is
3348 passed to this function.
3350 In case things go wrong while processing this function, causing an error that
3351 may re-enter this function, there is a recursion check.
3354 reason What $smtp_notquit_reason will be set to in the ACL;
3355 if NULL, the ACL is not run
3356 code The error code to return as part of the response
3357 defaultrespond The default message if there's no user_msg
3363 smtp_notquit_exit(uschar *reason, uschar *code, uschar *defaultrespond, ...)
3366 uschar *user_msg = NULL;
3367 uschar *log_msg = NULL;
3369 /* Check for recursive acll */
3371 if (smtp_exit_function_called)
3373 log_write(0, LOG_PANIC, "smtp_notquit_exit() called more than once (%s)",
3377 smtp_exit_function_called = TRUE;
3379 /* Call the not-QUIT ACL, if there is one, unless no reason is given. */
3381 if (acl_smtp_notquit && reason)
3383 smtp_notquit_reason = reason;
3384 if ((rc = acl_check(ACL_WHERE_NOTQUIT, NULL, acl_smtp_notquit, &user_msg,
3385 &log_msg)) == ERROR)
3386 log_write(0, LOG_MAIN|LOG_PANIC, "ACL for not-QUIT returned ERROR: %s",
3390 /* Write an SMTP response if we are expected to give one. As the default
3391 responses are all internal, they should always fit in the buffer, but code a
3392 warning, just in case. Note that string_vformat() still leaves a complete
3393 string, even if it is incomplete. */
3395 if (code && defaultrespond)
3398 smtp_respond(code, 3, TRUE, user_msg);
3403 va_start(ap, defaultrespond);
3404 if (!string_vformat(buffer, sizeof(buffer), CS defaultrespond, ap))
3405 log_write(0, LOG_MAIN|LOG_PANIC, "string too large in smtp_notquit_exit()");
3406 smtp_printf("%s %s\r\n", FALSE, code, buffer);
3416 /*************************************************
3417 * Verify HELO argument *
3418 *************************************************/
3420 /* This function is called if helo_verify_hosts or helo_try_verify_hosts is
3421 matched. It is also called from ACL processing if verify = helo is used and
3422 verification was not previously tried (i.e. helo_try_verify_hosts was not
3423 matched). The result of its processing is to set helo_verified and
3424 helo_verify_failed. These variables should both be FALSE for this function to
3427 Note that EHLO/HELO is legitimately allowed to quote an address literal. Allow
3428 for IPv6 ::ffff: literals.
3431 Returns: TRUE if testing was completed;
3432 FALSE on a temporary failure
3436 smtp_verify_helo(void)
3440 HDEBUG(D_receive) debug_printf("verifying EHLO/HELO argument \"%s\"\n",
3443 if (sender_helo_name == NULL)
3445 HDEBUG(D_receive) debug_printf("no EHLO/HELO command was issued\n");
3448 /* Deal with the case of -bs without an IP address */
3450 else if (sender_host_address == NULL)
3452 HDEBUG(D_receive) debug_printf("no client IP address: assume success\n");
3453 helo_verified = TRUE;
3456 /* Deal with the more common case when there is a sending IP address */
3458 else if (sender_helo_name[0] == '[')
3460 helo_verified = Ustrncmp(sender_helo_name+1, sender_host_address,
3461 Ustrlen(sender_host_address)) == 0;
3466 if (strncmpic(sender_host_address, US"::ffff:", 7) == 0)
3467 helo_verified = Ustrncmp(sender_helo_name + 1,
3468 sender_host_address + 7, Ustrlen(sender_host_address) - 7) == 0;
3473 { if (helo_verified) debug_printf("matched host address\n"); }
3476 /* Do a reverse lookup if one hasn't already given a positive or negative
3477 response. If that fails, or the name doesn't match, try checking with a forward
3482 if (sender_host_name == NULL && !host_lookup_failed)
3483 yield = host_name_lookup() != DEFER;
3485 /* If a host name is known, check it and all its aliases. */
3487 if (sender_host_name)
3488 if ((helo_verified = strcmpic(sender_host_name, sender_helo_name) == 0))
3490 sender_helo_dnssec = sender_host_dnssec;
3491 HDEBUG(D_receive) debug_printf("matched host name\n");
3495 uschar **aliases = sender_host_aliases;
3497 if ((helo_verified = strcmpic(*aliases++, sender_helo_name) == 0))
3499 sender_helo_dnssec = sender_host_dnssec;
3503 HDEBUG(D_receive) if (helo_verified)
3504 debug_printf("matched alias %s\n", *(--aliases));
3507 /* Final attempt: try a forward lookup of the helo name */
3516 h.name = sender_helo_name;
3523 HDEBUG(D_receive) debug_printf("getting IP address for %s\n",
3525 rc = host_find_bydns(&h, NULL, HOST_FIND_BY_A,
3526 NULL, NULL, NULL, &d, NULL, NULL);
3527 if (rc == HOST_FOUND || rc == HOST_FOUND_LOCAL)
3528 for (hh = &h; hh; hh = hh->next)
3529 if (Ustrcmp(hh->address, sender_host_address) == 0)
3531 helo_verified = TRUE;
3532 if (h.dnssec == DS_YES) sender_helo_dnssec = TRUE;
3535 debug_printf("IP address for %s matches calling address\n"
3536 "Forward DNS security status: %sverified\n",
3537 sender_helo_name, sender_helo_dnssec ? "" : "un");
3544 if (!helo_verified) helo_verify_failed = TRUE; /* We've tried ... */
3551 /*************************************************
3552 * Send user response message *
3553 *************************************************/
3555 /* This function is passed a default response code and a user message. It calls
3556 smtp_message_code() to check and possibly modify the response code, and then
3557 calls smtp_respond() to transmit the response. I put this into a function
3558 just to avoid a lot of repetition.
3561 code the response code
3562 user_msg the user message
3568 smtp_user_msg(uschar *code, uschar *user_msg)
3571 smtp_message_code(&code, &len, &user_msg, NULL, TRUE);
3572 smtp_respond(code, len, TRUE, user_msg);
3578 smtp_in_auth(auth_instance *au, uschar ** s, uschar ** ss)
3580 const uschar *set_id = NULL;
3583 /* Run the checking code, passing the remainder of the command line as
3584 data. Initials the $auth<n> variables as empty. Initialize $0 empty and set
3585 it as the only set numerical variable. The authenticator may set $auth<n>
3586 and also set other numeric variables. The $auth<n> variables are preferred
3587 nowadays; the numerical variables remain for backwards compatibility.
3589 Afterwards, have a go at expanding the set_id string, even if
3590 authentication failed - for bad passwords it can be useful to log the
3591 userid. On success, require set_id to expand and exist, and put it in
3592 authenticated_id. Save this in permanent store, as the working store gets
3593 reset at HELO, RSET, etc. */
3595 for (i = 0; i < AUTH_VARS; i++) auth_vars[i] = NULL;
3597 expand_nlength[0] = 0; /* $0 contains nothing */
3599 rc = (au->info->servercode)(au, smtp_cmd_data);
3600 if (au->set_id) set_id = expand_string(au->set_id);
3601 expand_nmax = -1; /* Reset numeric variables */
3602 for (i = 0; i < AUTH_VARS; i++) auth_vars[i] = NULL; /* Reset $auth<n> */
3604 /* The value of authenticated_id is stored in the spool file and printed in
3605 log lines. It must not contain binary zeros or newline characters. In
3606 normal use, it never will, but when playing around or testing, this error
3607 can (did) happen. To guard against this, ensure that the id contains only
3608 printing characters. */
3610 if (set_id) set_id = string_printing(set_id);
3612 /* For the non-OK cases, set up additional logging data if set_id
3616 set_id = set_id && *set_id
3617 ? string_sprintf(" (set_id=%s)", set_id) : US"";
3619 /* Switch on the result */
3624 if (!au->set_id || set_id) /* Complete success */
3626 if (set_id) authenticated_id = string_copy_malloc(set_id);
3627 sender_host_authenticated = au->name;
3628 authentication_failed = FALSE;
3629 authenticated_fail_id = NULL; /* Impossible to already be set? */
3632 (sender_host_address ? protocols : protocols_local)
3633 [pextend + pauthed + (tls_in.active >= 0 ? pcrpted:0)];
3634 *s = *ss = US"235 Authentication succeeded";
3635 authenticated_by = au;
3639 /* Authentication succeeded, but we failed to expand the set_id string.
3640 Treat this as a temporary error. */
3642 auth_defer_msg = expand_string_message;
3646 if (set_id) authenticated_fail_id = string_copy_malloc(set_id);
3647 *s = string_sprintf("435 Unable to authenticate at present%s",
3648 auth_defer_user_msg);
3649 *ss = string_sprintf("435 Unable to authenticate at present%s: %s",
3650 set_id, auth_defer_msg);
3654 *s = *ss = US"501 Invalid base64 data";
3658 *s = *ss = US"501 Authentication cancelled";
3662 *s = *ss = US"553 Initial data not expected";
3666 if (set_id) authenticated_fail_id = string_copy_malloc(set_id);
3667 *s = US"535 Incorrect authentication data";
3668 *ss = string_sprintf("535 Incorrect authentication data%s", set_id);
3672 if (set_id) authenticated_fail_id = string_copy_malloc(set_id);
3673 *s = US"435 Internal error";
3674 *ss = string_sprintf("435 Internal error%s: return %d from authentication "
3675 "check", set_id, rc);
3687 qualify_recipient(uschar ** recipient, uschar * smtp_cmd_data, uschar * tag)
3690 if (allow_unqualified_recipient || strcmpic(*recipient, US"postmaster") == 0)
3692 DEBUG(D_receive) debug_printf("unqualified address %s accepted\n",
3694 rd = Ustrlen(recipient) + 1;
3695 *recipient = rewrite_address_qualify(*recipient, TRUE);
3698 smtp_printf("501 %s: recipient address must contain a domain\r\n", FALSE,
3700 log_write(L_smtp_syntax_error,
3701 LOG_MAIN|LOG_REJECT, "unqualified %s rejected: <%s> %s%s",
3702 tag, *recipient, host_and_ident(TRUE), host_lookup_msg);
3710 smtp_quit_handler(uschar ** user_msgp, uschar ** log_msgp)
3713 incomplete_transaction_log(US"QUIT");
3716 int rc = acl_check(ACL_WHERE_QUIT, NULL, acl_smtp_quit, user_msgp, log_msgp);
3718 log_write(0, LOG_MAIN|LOG_PANIC, "ACL for QUIT returned ERROR: %s",
3722 smtp_respond(US"221", 3, TRUE, *user_msgp);
3724 smtp_printf("221 %s closing connection\r\n", FALSE, smtp_active_hostname);
3727 tls_close(TRUE, TRUE);
3730 log_write(L_smtp_connection, LOG_MAIN, "%s closed by QUIT",
3731 smtp_get_connection_info());
3736 smtp_rset_handler(void)
3739 incomplete_transaction_log(US"RSET");
3740 smtp_printf("250 Reset OK\r\n", FALSE);
3741 cmd_list[CMD_LIST_RSET].is_mail_cmd = FALSE;
3746 /*************************************************
3747 * Initialize for SMTP incoming message *
3748 *************************************************/
3750 /* This function conducts the initial dialogue at the start of an incoming SMTP
3751 message, and builds a list of recipients. However, if the incoming message
3752 is part of a batch (-bS option) a separate function is called since it would
3753 be messy having tests splattered about all over this function. This function
3754 therefore handles the case where interaction is occurring. The input and output
3755 files are set up in smtp_in and smtp_out.
3757 The global recipients_list is set to point to a vector of recipient_item
3758 blocks, whose number is given by recipients_count. This is extended by the
3759 receive_add_recipient() function. The global variable sender_address is set to
3760 the sender's address. The yield is +1 if a message has been successfully
3761 started, 0 if a QUIT command was encountered or the connection was refused from
3762 the particular host, or -1 if the connection was lost.
3766 Returns: > 0 message successfully started (reached DATA)
3767 = 0 QUIT read or end of file reached or call refused
3772 smtp_setup_msg(void)
3775 BOOL toomany = FALSE;
3776 BOOL discarded = FALSE;
3777 BOOL last_was_rej_mail = FALSE;
3778 BOOL last_was_rcpt = FALSE;
3779 void *reset_point = store_get(0);
3781 DEBUG(D_receive) debug_printf("smtp_setup_msg entered\n");
3783 /* Reset for start of new message. We allow one RSET not to be counted as a
3784 nonmail command, for those MTAs that insist on sending it between every
3785 message. Ditto for EHLO/HELO and for STARTTLS, to allow for going in and out of
3786 TLS between messages (an Exim client may do this if it has messages queued up
3787 for the host). Note: we do NOT reset AUTH at this point. */
3789 smtp_reset(reset_point);
3790 message_ended = END_NOTSTARTED;
3792 chunking_state = chunking_offered ? CHUNKING_OFFERED : CHUNKING_NOT_OFFERED;
3794 cmd_list[CMD_LIST_RSET].is_mail_cmd = TRUE;
3795 cmd_list[CMD_LIST_HELO].is_mail_cmd = TRUE;
3796 cmd_list[CMD_LIST_EHLO].is_mail_cmd = TRUE;
3798 cmd_list[CMD_LIST_STARTTLS].is_mail_cmd = TRUE;
3799 cmd_list[CMD_LIST_TLS_AUTH].is_mail_cmd = TRUE;
3802 /* Set the local signal handler for SIGTERM - it tries to end off tidily */
3804 os_non_restarting_signal(SIGTERM, command_sigterm_handler);
3806 /* Batched SMTP is handled in a different function. */
3808 if (smtp_batched_input) return smtp_setup_batch_msg();
3810 /* Deal with SMTP commands. This loop is exited by setting done to a POSITIVE
3811 value. The values are 2 larger than the required yield of the function. */
3815 const uschar **argv;
3816 uschar *etrn_command;
3817 uschar *etrn_serialize_key;
3819 uschar *log_msg, *smtp_code;
3820 uschar *user_msg = NULL;
3821 uschar *recipient = NULL;
3822 uschar *hello = NULL;
3824 BOOL was_rej_mail = FALSE;
3825 BOOL was_rcpt = FALSE;
3826 void (*oldsignal)(int);
3828 int start, end, sender_domain, recipient_domain;
3832 uschar *orcpt = NULL;
3837 /* Check once per STARTTLS or SSL-on-connect for a TLS AUTH */
3838 if ( tls_in.active >= 0
3840 && tls_in.certificate_verified
3841 && cmd_list[CMD_LIST_TLS_AUTH].is_mail_cmd
3844 cmd_list[CMD_LIST_TLS_AUTH].is_mail_cmd = FALSE;
3846 && (rc = acl_check(ACL_WHERE_AUTH, NULL, acl_smtp_auth,
3847 &user_msg, &log_msg)) != OK
3850 done = smtp_handle_acl_fail(ACL_WHERE_AUTH, rc, user_msg, log_msg);
3854 for (au = auths; au; au = au->next)
3855 if (strcmpic(US"tls", au->driver_name) == 0)
3857 smtp_cmd_data = NULL;
3859 if (smtp_in_auth(au, &s, &ss) == OK)
3860 { DEBUG(D_auth) debug_printf("tls auth succeeded\n"); }
3862 { DEBUG(D_auth) debug_printf("tls auth not succeeded\n"); }
3869 if (smtp_in) /* Avoid pure-ACKs while in cmd pingpong phase */
3870 (void) setsockopt(fileno(smtp_in), IPPROTO_TCP, TCP_QUICKACK,
3871 US &off, sizeof(off));
3874 switch(smtp_read_command(TRUE, GETC_BUFFER_UNLIMITED))
3876 /* The AUTH command is not permitted to occur inside a transaction, and may
3877 occur successfully only once per connection. Actually, that isn't quite
3878 true. When TLS is started, all previous information about a connection must
3879 be discarded, so a new AUTH is permitted at that time.
3881 AUTH may only be used when it has been advertised. However, it seems that
3882 there are clients that send AUTH when it hasn't been advertised, some of
3883 them even doing this after HELO. And there are MTAs that accept this. Sigh.
3884 So there's a get-out that allows this to happen.
3886 AUTH is initially labelled as a "nonmail command" so that one occurrence
3887 doesn't get counted. We change the label here so that multiple failing
3888 AUTHS will eventually hit the nonmail threshold. */
3892 authentication_failed = TRUE;
3893 cmd_list[CMD_LIST_AUTH].is_mail_cmd = FALSE;
3895 if (!auth_advertised && !allow_auth_unadvertised)
3897 done = synprot_error(L_smtp_protocol_error, 503, NULL,
3898 US"AUTH command used when not advertised");
3901 if (sender_host_authenticated)
3903 done = synprot_error(L_smtp_protocol_error, 503, NULL,
3904 US"already authenticated");
3909 done = synprot_error(L_smtp_protocol_error, 503, NULL,
3910 US"not permitted in mail transaction");
3917 && (rc = acl_check(ACL_WHERE_AUTH, NULL, acl_smtp_auth,
3918 &user_msg, &log_msg)) != OK
3921 done = smtp_handle_acl_fail(ACL_WHERE_AUTH, rc, user_msg, log_msg);
3925 /* Find the name of the requested authentication mechanism. */
3928 while ((c = *smtp_cmd_data) != 0 && !isspace(c))
3930 if (!isalnum(c) && c != '-' && c != '_')
3932 done = synprot_error(L_smtp_syntax_error, 501, NULL,
3933 US"invalid character in authentication mechanism name");
3939 /* If not at the end of the line, we must be at white space. Terminate the
3940 name and move the pointer on to any data that may be present. */
3942 if (*smtp_cmd_data != 0)
3944 *smtp_cmd_data++ = 0;
3945 while (isspace(*smtp_cmd_data)) smtp_cmd_data++;
3948 /* Search for an authentication mechanism which is configured for use
3949 as a server and which has been advertised (unless, sigh, allow_auth_
3950 unadvertised is set). */
3952 for (au = auths; au; au = au->next)
3953 if (strcmpic(s, au->public_name) == 0 && au->server &&
3954 (au->advertised || allow_auth_unadvertised))
3959 c = smtp_in_auth(au, &s, &ss);
3961 smtp_printf("%s\r\n", FALSE, s);
3963 log_write(0, LOG_MAIN|LOG_REJECT, "%s authenticator failed for %s: %s",
3964 au->name, host_and_ident(FALSE), ss);
3967 done = synprot_error(L_smtp_protocol_error, 504, NULL,
3968 string_sprintf("%s authentication mechanism not supported", s));
3970 break; /* AUTH_CMD */
3972 /* The HELO/EHLO commands are permitted to appear in the middle of a
3973 session as well as at the beginning. They have the effect of a reset in
3974 addition to their other functions. Their absence at the start cannot be
3975 taken to be an error.
3979 If the EHLO command is not acceptable to the SMTP server, 501, 500,
3980 or 502 failure replies MUST be returned as appropriate. The SMTP
3981 server MUST stay in the same state after transmitting these replies
3982 that it was in before the EHLO was received.
3984 Therefore, we do not do the reset until after checking the command for
3985 acceptability. This change was made for Exim release 4.11. Previously
3986 it did the reset first. */
3999 HELO_EHLO: /* Common code for HELO and EHLO */
4000 cmd_list[CMD_LIST_HELO].is_mail_cmd = FALSE;
4001 cmd_list[CMD_LIST_EHLO].is_mail_cmd = FALSE;
4003 /* Reject the HELO if its argument was invalid or non-existent. A
4004 successful check causes the argument to be saved in malloc store. */
4006 if (!check_helo(smtp_cmd_data))
4008 smtp_printf("501 Syntactically invalid %s argument(s)\r\n", FALSE, hello);
4010 log_write(0, LOG_MAIN|LOG_REJECT, "rejected %s from %s: syntactically "
4011 "invalid argument(s): %s", hello, host_and_ident(FALSE),
4012 (*smtp_cmd_argument == 0)? US"(no argument given)" :
4013 string_printing(smtp_cmd_argument));
4015 if (++synprot_error_count > smtp_max_synprot_errors)
4017 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
4018 "syntax or protocol errors (last command was \"%s\")",
4019 host_and_ident(FALSE), string_printing(smtp_cmd_buffer));
4026 /* If sender_host_unknown is true, we have got here via the -bs interface,
4027 not called from inetd. Otherwise, we are running an IP connection and the
4028 host address will be set. If the helo name is the primary name of this
4029 host and we haven't done a reverse lookup, force one now. If helo_required
4030 is set, ensure that the HELO name matches the actual host. If helo_verify
4031 is set, do the same check, but softly. */
4033 if (!sender_host_unknown)
4035 BOOL old_helo_verified = helo_verified;
4036 uschar *p = smtp_cmd_data;
4038 while (*p != 0 && !isspace(*p)) { *p = tolower(*p); p++; }
4041 /* Force a reverse lookup if HELO quoted something in helo_lookup_domains
4042 because otherwise the log can be confusing. */
4044 if (sender_host_name == NULL &&
4045 (deliver_domain = sender_helo_name, /* set $domain */
4046 match_isinlist(sender_helo_name, CUSS &helo_lookup_domains, 0,
4047 &domainlist_anchor, NULL, MCL_DOMAIN, TRUE, NULL)) == OK)
4048 (void)host_name_lookup();
4050 /* Rebuild the fullhost info to include the HELO name (and the real name
4051 if it was looked up.) */
4053 host_build_sender_fullhost(); /* Rebuild */
4054 set_process_info("handling%s incoming connection from %s",
4055 (tls_in.active >= 0)? " TLS" : "", host_and_ident(FALSE));
4057 /* Verify if configured. This doesn't give much security, but it does
4058 make some people happy to be able to do it. If helo_required is set,
4059 (host matches helo_verify_hosts) failure forces rejection. If helo_verify
4060 is set (host matches helo_try_verify_hosts), it does not. This is perhaps
4061 now obsolescent, since the verification can now be requested selectively
4064 helo_verified = helo_verify_failed = sender_helo_dnssec = FALSE;
4065 if (helo_required || helo_verify)
4067 BOOL tempfail = !smtp_verify_helo();
4072 smtp_printf("%d %s argument does not match calling host\r\n", FALSE,
4073 tempfail? 451 : 550, hello);
4074 log_write(0, LOG_MAIN|LOG_REJECT, "%srejected \"%s %s\" from %s",
4075 tempfail? "temporarily " : "",
4076 hello, sender_helo_name, host_and_ident(FALSE));
4077 helo_verified = old_helo_verified;
4078 break; /* End of HELO/EHLO processing */
4080 HDEBUG(D_all) debug_printf("%s verification failed but host is in "
4081 "helo_try_verify_hosts\n", hello);
4086 #ifdef EXPERIMENTAL_SPF
4087 /* set up SPF context */
4088 spf_init(sender_helo_name, sender_host_address);
4091 /* Apply an ACL check if one is defined; afterwards, recheck
4092 synchronization in case the client started sending in a delay. */
4095 if ((rc = acl_check(ACL_WHERE_HELO, NULL, acl_smtp_helo,
4096 &user_msg, &log_msg)) != OK)
4098 done = smtp_handle_acl_fail(ACL_WHERE_HELO, rc, user_msg, log_msg);
4099 sender_helo_name = NULL;
4100 host_build_sender_fullhost(); /* Rebuild */
4103 else if (!check_sync()) goto SYNC_FAILURE;
4105 /* Generate an OK reply. The default string includes the ident if present,
4106 and also the IP address if present. Reflecting back the ident is intended
4107 as a deterrent to mail forgers. For maximum efficiency, and also because
4108 some broken systems expect each response to be in a single packet, arrange
4109 that the entire reply is sent in one write(). */
4111 auth_advertised = FALSE;
4112 pipelining_advertised = FALSE;
4114 tls_advertised = FALSE;
4116 dsn_advertised = FALSE;
4118 smtputf8_advertised = FALSE;
4121 smtp_code = US"250 "; /* Default response code plus space*/
4124 s = string_sprintf("%.3s %s Hello %s%s%s",
4126 smtp_active_hostname,
4127 sender_ident ? sender_ident : US"",
4128 sender_ident ? US" at " : US"",
4129 sender_host_name ? sender_host_name : sender_helo_name);
4130 g = string_cat(NULL, s);
4132 if (sender_host_address)
4134 g = string_catn(g, US" [", 2);
4135 g = string_cat (g, sender_host_address);
4136 g = string_catn(g, US"]", 1);
4140 /* A user-supplied EHLO greeting may not contain more than one line. Note
4141 that the code returned by smtp_message_code() includes the terminating
4142 whitespace character. */
4148 smtp_message_code(&smtp_code, &codelen, &user_msg, NULL, TRUE);
4149 s = string_sprintf("%.*s%s", codelen, smtp_code, user_msg);
4150 if ((ss = strpbrk(CS s, "\r\n")) != NULL)
4152 log_write(0, LOG_MAIN|LOG_PANIC, "EHLO/HELO response must not contain "
4153 "newlines: message truncated: %s", string_printing(s));
4156 g = string_cat(NULL, s);
4159 g = string_catn(g, US"\r\n", 2);
4161 /* If we received EHLO, we must create a multiline response which includes
4162 the functions supported. */
4168 /* I'm not entirely happy with this, as an MTA is supposed to check
4169 that it has enough room to accept a message of maximum size before
4170 it sends this. However, there seems little point in not sending it.
4171 The actual size check happens later at MAIL FROM time. By postponing it
4172 till then, VRFY and EXPN can be used after EHLO when space is short. */
4174 if (thismessage_size_limit > 0)
4176 sprintf(CS big_buffer, "%.3s-SIZE %d\r\n", smtp_code,
4177 thismessage_size_limit);
4178 g = string_cat(g, big_buffer);
4182 g = string_catn(g, smtp_code, 3);
4183 g = string_catn(g, US"-SIZE\r\n", 7);
4186 /* Exim does not do protocol conversion or data conversion. It is 8-bit
4187 clean; if it has an 8-bit character in its hand, it just sends it. It
4188 cannot therefore specify 8BITMIME and remain consistent with the RFCs.
4189 However, some users want this option simply in order to stop MUAs
4190 mangling messages that contain top-bit-set characters. It is therefore
4191 provided as an option. */
4193 if (accept_8bitmime)
4195 g = string_catn(g, smtp_code, 3);
4196 g = string_catn(g, US"-8BITMIME\r\n", 11);
4199 /* Advertise DSN support if configured to do so. */
4200 if (verify_check_host(&dsn_advertise_hosts) != FAIL)
4202 g = string_catn(g, smtp_code, 3);
4203 g = string_catn(g, US"-DSN\r\n", 6);
4204 dsn_advertised = TRUE;
4207 /* Advertise ETRN/VRFY/EXPN if there's are ACL checking whether a host is
4208 permitted to issue them; a check is made when any host actually tries. */
4212 g = string_catn(g, smtp_code, 3);
4213 g = string_catn(g, US"-ETRN\r\n", 7);
4217 g = string_catn(g, smtp_code, 3);
4218 g = string_catn(g, US"-VRFY\r\n", 7);
4222 g = string_catn(g, smtp_code, 3);
4223 g = string_catn(g, US"-EXPN\r\n", 7);
4226 /* Exim is quite happy with pipelining, so let the other end know that
4227 it is safe to use it, unless advertising is disabled. */
4229 if (pipelining_enable &&
4230 verify_check_host(&pipelining_advertise_hosts) == OK)
4232 g = string_catn(g, smtp_code, 3);
4233 g = string_catn(g, US"-PIPELINING\r\n", 13);
4234 sync_cmd_limit = NON_SYNC_CMD_PIPELINING;
4235 pipelining_advertised = TRUE;
4239 /* If any server authentication mechanisms are configured, advertise
4240 them if the current host is in auth_advertise_hosts. The problem with
4241 advertising always is that some clients then require users to
4242 authenticate (and aren't configurable otherwise) even though it may not
4243 be necessary (e.g. if the host is in host_accept_relay).
4245 RFC 2222 states that SASL mechanism names contain only upper case
4246 letters, so output the names in upper case, though we actually recognize
4247 them in either case in the AUTH command. */
4251 && !sender_host_authenticated
4253 && verify_check_host(&auth_advertise_hosts) == OK
4258 for (au = auths; au; au = au->next)
4260 au->advertised = FALSE;
4263 DEBUG(D_auth+D_expand) debug_printf_indent(
4264 "Evaluating advertise_condition for %s athenticator\n",
4266 if ( !au->advertise_condition
4267 || expand_check_condition(au->advertise_condition, au->name,
4274 g = string_catn(g, smtp_code, 3);
4275 g = string_catn(g, US"-AUTH", 5);
4277 auth_advertised = TRUE;
4280 g = string_catn(g, US" ", 1);
4281 g = string_cat (g, au->public_name);
4282 while (++saveptr < g->ptr) g->s[saveptr] = toupper(g->s[saveptr]);
4283 au->advertised = TRUE;
4288 if (!first) g = string_catn(g, US"\r\n", 2);
4291 /* RFC 3030 CHUNKING */
4293 if (verify_check_host(&chunking_advertise_hosts) != FAIL)
4295 g = string_catn(g, smtp_code, 3);
4296 g = string_catn(g, US"-CHUNKING\r\n", 11);
4297 chunking_offered = TRUE;
4298 chunking_state = CHUNKING_OFFERED;
4301 /* Advertise TLS (Transport Level Security) aka SSL (Secure Socket Layer)
4302 if it has been included in the binary, and the host matches
4303 tls_advertise_hosts. We must *not* advertise if we are already in a
4304 secure connection. */
4307 if (tls_in.active < 0 &&
4308 verify_check_host(&tls_advertise_hosts) != FAIL)
4310 g = string_catn(g, smtp_code, 3);
4311 g = string_catn(g, US"-STARTTLS\r\n", 11);
4312 tls_advertised = TRUE;
4316 #ifndef DISABLE_PRDR
4317 /* Per Recipient Data Response, draft by Eric A. Hall extending RFC */
4320 g = string_catn(g, smtp_code, 3);
4321 g = string_catn(g, US"-PRDR\r\n", 7);
4326 if ( accept_8bitmime
4327 && verify_check_host(&smtputf8_advertise_hosts) != FAIL)
4329 g = string_catn(g, smtp_code, 3);
4330 g = string_catn(g, US"-SMTPUTF8\r\n", 11);
4331 smtputf8_advertised = TRUE;
4335 /* Finish off the multiline reply with one that is always available. */
4337 g = string_catn(g, smtp_code, 3);
4338 g = string_catn(g, US" HELP\r\n", 7);
4341 /* Terminate the string (for debug), write it, and note that HELO/EHLO
4345 if (tls_in.active >= 0) (void)tls_write(TRUE, g->s, g->ptr, FALSE); else
4349 int i = fwrite(g->s, 1, g->ptr, smtp_out); i = i; /* compiler quietening */
4355 (void) string_from_gstring(g);
4356 while ((cr = Ustrchr(g->s, '\r')) != NULL) /* lose CRs */
4357 memmove(cr, cr + 1, (g->ptr--) - (cr - g->s));
4358 debug_printf("SMTP>> %s", g->s);
4362 /* Reset the protocol and the state, abandoning any previous message. */
4364 (sender_host_address ? protocols : protocols_local)
4366 ? pextend + (sender_host_authenticated ? pauthed : 0)
4368 + (tls_in.active >= 0 ? pcrpted : 0)
4370 cancel_cutthrough_connection(TRUE, US"sent EHLO response");
4371 smtp_reset(reset_point);
4373 break; /* HELO/EHLO */
4376 /* The MAIL command requires an address as an operand. All we do
4377 here is to parse it for syntactic correctness. The form "<>" is
4378 a special case which converts into an empty string. The start/end
4379 pointers in the original are not used further for this address, as
4380 it is the canonical extracted address which is all that is kept. */
4384 smtp_mailcmd_count++; /* Count for limit and ratelimit */
4385 was_rej_mail = TRUE; /* Reset if accepted */
4386 env_mail_type_t * mail_args; /* Sanity check & validate args */
4388 if (helo_required && !helo_seen)
4390 smtp_printf("503 HELO or EHLO required\r\n", FALSE);
4391 log_write(0, LOG_MAIN|LOG_REJECT, "rejected MAIL from %s: no "
4392 "HELO/EHLO given", host_and_ident(FALSE));
4396 if (sender_address != NULL)
4398 done = synprot_error(L_smtp_protocol_error, 503, NULL,
4399 US"sender already given");
4403 if (smtp_cmd_data[0] == 0)
4405 done = synprot_error(L_smtp_protocol_error, 501, NULL,
4406 US"MAIL must have an address operand");
4410 /* Check to see if the limit for messages per connection would be
4411 exceeded by accepting further messages. */
4413 if (smtp_accept_max_per_connection > 0 &&
4414 smtp_mailcmd_count > smtp_accept_max_per_connection)
4416 smtp_printf("421 too many messages in this connection\r\n", FALSE);
4417 log_write(0, LOG_MAIN|LOG_REJECT, "rejected MAIL command %s: too many "
4418 "messages in one connection", host_and_ident(TRUE));
4422 /* Reset for start of message - even if this is going to fail, we
4423 obviously need to throw away any previous data. */
4425 cancel_cutthrough_connection(TRUE, US"MAIL received");
4426 smtp_reset(reset_point);
4428 sender_data = recipient_data = NULL;
4430 /* Loop, checking for ESMTP additions to the MAIL FROM command. */
4434 uschar *name, *value, *end;
4435 unsigned long int size;
4436 BOOL arg_error = FALSE;
4438 if (!extract_option(&name, &value)) break;
4440 for (mail_args = env_mail_type_list;
4441 mail_args->value != ENV_MAIL_OPT_NULL;
4444 if (strcmpic(name, mail_args->name) == 0)
4446 if (mail_args->need_value && strcmpic(value, US"") == 0)
4449 switch(mail_args->value)
4451 /* Handle SIZE= by reading the value. We don't do the check till later,
4452 in order to be able to log the sender address on failure. */
4453 case ENV_MAIL_OPT_SIZE:
4454 if (((size = Ustrtoul(value, &end, 10)), *end == 0))
4456 if ((size == ULONG_MAX && errno == ERANGE) || size > INT_MAX)
4458 message_size = (int)size;
4464 /* If this session was initiated with EHLO and accept_8bitmime is set,
4465 Exim will have indicated that it supports the BODY=8BITMIME option. In
4466 fact, it does not support this according to the RFCs, in that it does not
4467 take any special action for forwarding messages containing 8-bit
4468 characters. That is why accept_8bitmime is not the default setting, but
4469 some sites want the action that is provided. We recognize both "8BITMIME"
4470 and "7BIT" as body types, but take no action. */
4471 case ENV_MAIL_OPT_BODY:
4472 if (accept_8bitmime) {
4473 if (strcmpic(value, US"8BITMIME") == 0)
4475 else if (strcmpic(value, US"7BIT") == 0)
4480 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4481 US"invalid data for BODY");
4484 DEBUG(D_receive) debug_printf("8BITMIME: %d\n", body_8bitmime);
4490 /* Handle the two DSN options, but only if configured to do so (which
4491 will have caused "DSN" to be given in the EHLO response). The code itself
4492 is included only if configured in at build time. */
4494 case ENV_MAIL_OPT_RET:
4497 /* Check if RET has already been set */
4500 synprot_error(L_smtp_syntax_error, 501, NULL,
4501 US"RET can be specified once only");
4504 dsn_ret = strcmpic(value, US"HDRS") == 0
4506 : strcmpic(value, US"FULL") == 0
4509 DEBUG(D_receive) debug_printf("DSN_RET: %d\n", dsn_ret);
4510 /* Check for invalid invalid value, and exit with error */
4513 synprot_error(L_smtp_syntax_error, 501, NULL,
4514 US"Value for RET is invalid");
4519 case ENV_MAIL_OPT_ENVID:
4522 /* Check if the dsn envid has been already set */
4523 if (dsn_envid != NULL)
4525 synprot_error(L_smtp_syntax_error, 501, NULL,
4526 US"ENVID can be specified once only");
4529 dsn_envid = string_copy(value);
4530 DEBUG(D_receive) debug_printf("DSN_ENVID: %s\n", dsn_envid);
4534 /* Handle the AUTH extension. If the value given is not "<>" and either
4535 the ACL says "yes" or there is no ACL but the sending host is
4536 authenticated, we set it up as the authenticated sender. However, if the
4537 authenticator set a condition to be tested, we ignore AUTH on MAIL unless
4538 the condition is met. The value of AUTH is an xtext, which means that +,
4539 = and cntrl chars are coded in hex; however "<>" is unaffected by this
4541 case ENV_MAIL_OPT_AUTH:
4542 if (Ustrcmp(value, "<>") != 0)
4547 if (auth_xtextdecode(value, &authenticated_sender) < 0)
4549 /* Put back terminator overrides for error message */
4552 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4553 US"invalid data for AUTH");
4556 if (acl_smtp_mailauth == NULL)
4558 ignore_msg = US"client not authenticated";
4559 rc = (sender_host_authenticated != NULL)? OK : FAIL;
4563 ignore_msg = US"rejected by ACL";
4564 rc = acl_check(ACL_WHERE_MAILAUTH, NULL, acl_smtp_mailauth,
4565 &user_msg, &log_msg);
4571 if (authenticated_by == NULL ||
4572 authenticated_by->mail_auth_condition == NULL ||
4573 expand_check_condition(authenticated_by->mail_auth_condition,
4574 authenticated_by->name, US"authenticator"))
4575 break; /* Accept the AUTH */
4577 ignore_msg = US"server_mail_auth_condition failed";
4578 if (authenticated_id != NULL)
4579 ignore_msg = string_sprintf("%s: authenticated ID=\"%s\"",
4580 ignore_msg, authenticated_id);
4585 authenticated_sender = NULL;
4586 log_write(0, LOG_MAIN, "ignoring AUTH=%s from %s (%s)",
4587 value, host_and_ident(TRUE), ignore_msg);
4590 /* Should only get DEFER or ERROR here. Put back terminator
4591 overrides for error message */
4596 (void)smtp_handle_acl_fail(ACL_WHERE_MAILAUTH, rc, user_msg,
4603 #ifndef DISABLE_PRDR
4604 case ENV_MAIL_OPT_PRDR:
4606 prdr_requested = TRUE;
4611 case ENV_MAIL_OPT_UTF8:
4612 if (smtputf8_advertised)
4614 int old_pool = store_pool;
4616 DEBUG(D_receive) debug_printf("smtputf8 requested\n");
4617 message_smtputf8 = allow_utf8_domains = TRUE;
4618 store_pool = POOL_PERM;
4619 received_protocol = string_sprintf("utf8%s", received_protocol);
4620 store_pool = old_pool;
4624 /* No valid option. Stick back the terminator characters and break
4625 the loop. Do the name-terminator second as extract_option sets
4626 value==name when it found no equal-sign.
4627 An error for a malformed address will occur. */
4628 case ENV_MAIL_OPT_NULL:
4636 /* Break out of for loop if switch() had bad argument or
4637 when start of the email address is reached */
4638 if (arg_error) break;
4641 /* If we have passed the threshold for rate limiting, apply the current
4642 delay, and update it for next time, provided this is a limited host. */
4644 if (smtp_mailcmd_count > smtp_rlm_threshold &&
4645 verify_check_host(&smtp_ratelimit_hosts) == OK)
4647 DEBUG(D_receive) debug_printf("rate limit MAIL: delay %.3g sec\n",
4648 smtp_delay_mail/1000.0);
4649 millisleep((int)smtp_delay_mail);
4650 smtp_delay_mail *= smtp_rlm_factor;
4651 if (smtp_delay_mail > (double)smtp_rlm_limit)
4652 smtp_delay_mail = (double)smtp_rlm_limit;
4655 /* Now extract the address, first applying any SMTP-time rewriting. The
4656 TRUE flag allows "<>" as a sender address. */
4658 raw_sender = rewrite_existflags & rewrite_smtp
4659 ? rewrite_one(smtp_cmd_data, rewrite_smtp, NULL, FALSE, US"",
4660 global_rewrite_rules)
4664 parse_extract_address(raw_sender, &errmess, &start, &end, &sender_domain,
4669 done = synprot_error(L_smtp_syntax_error, 501, smtp_cmd_data, errmess);
4673 sender_address = raw_sender;
4675 /* If there is a configured size limit for mail, check that this message
4676 doesn't exceed it. The check is postponed to this point so that the sender
4679 if (thismessage_size_limit > 0 && message_size > thismessage_size_limit)
4681 smtp_printf("552 Message size exceeds maximum permitted\r\n", FALSE);
4682 log_write(L_size_reject,
4683 LOG_MAIN|LOG_REJECT, "rejected MAIL FROM:<%s> %s: "
4684 "message too big: size%s=%d max=%d",
4686 host_and_ident(TRUE),
4687 (message_size == INT_MAX)? ">" : "",
4689 thismessage_size_limit);
4690 sender_address = NULL;
4694 /* Check there is enough space on the disk unless configured not to.
4695 When smtp_check_spool_space is set, the check is for thismessage_size_limit
4696 plus the current message - i.e. we accept the message only if it won't
4697 reduce the space below the threshold. Add 5000 to the size to allow for
4698 overheads such as the Received: line and storing of recipients, etc.
4699 By putting the check here, even when SIZE is not given, it allow VRFY
4700 and EXPN etc. to be used when space is short. */
4702 if (!receive_check_fs(
4703 (smtp_check_spool_space && message_size >= 0)?
4704 message_size + 5000 : 0))
4706 smtp_printf("452 Space shortage, please try later\r\n", FALSE);
4707 sender_address = NULL;
4711 /* If sender_address is unqualified, reject it, unless this is a locally
4712 generated message, or the sending host or net is permitted to send
4713 unqualified addresses - typically local machines behaving as MUAs -
4714 in which case just qualify the address. The flag is set above at the start
4715 of the SMTP connection. */
4717 if (sender_domain == 0 && sender_address[0] != 0)
4719 if (allow_unqualified_sender)
4721 sender_domain = Ustrlen(sender_address) + 1;
4722 sender_address = rewrite_address_qualify(sender_address, FALSE);
4723 DEBUG(D_receive) debug_printf("unqualified address %s accepted\n",
4728 smtp_printf("501 %s: sender address must contain a domain\r\n", FALSE,
4730 log_write(L_smtp_syntax_error,
4731 LOG_MAIN|LOG_REJECT,
4732 "unqualified sender rejected: <%s> %s%s",
4734 host_and_ident(TRUE),
4736 sender_address = NULL;
4741 /* Apply an ACL check if one is defined, before responding. Afterwards,
4742 when pipelining is not advertised, do another sync check in case the ACL
4743 delayed and the client started sending in the meantime. */
4747 rc = acl_check(ACL_WHERE_MAIL, NULL, acl_smtp_mail, &user_msg, &log_msg);
4748 if (rc == OK && !pipelining_advertised && !check_sync())
4754 if (rc == OK || rc == DISCARD)
4756 BOOL more = pipeline_response();
4759 smtp_printf("%s%s%s", more, US"250 OK",
4760 #ifndef DISABLE_PRDR
4761 prdr_requested ? US", PRDR Requested" : US"",
4768 #ifndef DISABLE_PRDR
4770 user_msg = string_sprintf("%s%s", user_msg, US", PRDR Requested");
4772 smtp_user_msg(US"250", user_msg);
4774 smtp_delay_rcpt = smtp_rlr_base;
4775 recipients_discarded = (rc == DISCARD);
4776 was_rej_mail = FALSE;
4780 done = smtp_handle_acl_fail(ACL_WHERE_MAIL, rc, user_msg, log_msg);
4781 sender_address = NULL;
4786 /* The RCPT command requires an address as an operand. There may be any
4787 number of RCPT commands, specifying multiple recipients. We build them all
4788 into a data structure. The start/end values given by parse_extract_address
4789 are not used, as we keep only the extracted address. */
4794 was_rcpt = rcpt_in_progress = TRUE;
4796 /* There must be a sender address; if the sender was rejected and
4797 pipelining was advertised, we assume the client was pipelining, and do not
4798 count this as a protocol error. Reset was_rej_mail so that further RCPTs
4799 get the same treatment. */
4801 if (sender_address == NULL)
4803 if (pipelining_advertised && last_was_rej_mail)
4805 smtp_printf("503 sender not yet given\r\n", FALSE);
4806 was_rej_mail = TRUE;
4810 done = synprot_error(L_smtp_protocol_error, 503, NULL,
4811 US"sender not yet given");
4812 was_rcpt = FALSE; /* Not a valid RCPT */
4818 /* Check for an operand */
4820 if (smtp_cmd_data[0] == 0)
4822 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4823 US"RCPT must have an address operand");
4828 /* Set the DSN flags orcpt and dsn_flags from the session*/
4834 uschar *name, *value;
4836 if (!extract_option(&name, &value))
4839 if (dsn_advertised && strcmpic(name, US"ORCPT") == 0)
4841 /* Check whether orcpt has been already set */
4844 synprot_error(L_smtp_syntax_error, 501, NULL,
4845 US"ORCPT can be specified once only");
4848 orcpt = string_copy(value);
4849 DEBUG(D_receive) debug_printf("DSN orcpt: %s\n", orcpt);
4852 else if (dsn_advertised && strcmpic(name, US"NOTIFY") == 0)
4854 /* Check if the notify flags have been already set */
4857 synprot_error(L_smtp_syntax_error, 501, NULL,
4858 US"NOTIFY can be specified once only");
4861 if (strcmpic(value, US"NEVER") == 0)
4862 flags |= rf_notify_never;
4869 while (*pp != 0 && *pp != ',') pp++;
4870 if (*pp == ',') *pp++ = 0;
4871 if (strcmpic(p, US"SUCCESS") == 0)
4873 DEBUG(D_receive) debug_printf("DSN: Setting notify success\n");
4874 flags |= rf_notify_success;
4876 else if (strcmpic(p, US"FAILURE") == 0)
4878 DEBUG(D_receive) debug_printf("DSN: Setting notify failure\n");
4879 flags |= rf_notify_failure;
4881 else if (strcmpic(p, US"DELAY") == 0)
4883 DEBUG(D_receive) debug_printf("DSN: Setting notify delay\n");
4884 flags |= rf_notify_delay;
4888 /* Catch any strange values */
4889 synprot_error(L_smtp_syntax_error, 501, NULL,
4890 US"Invalid value for NOTIFY parameter");
4895 DEBUG(D_receive) debug_printf("DSN Flags: %x\n", flags);
4899 /* Unknown option. Stick back the terminator characters and break
4900 the loop. An error for a malformed address will occur. */
4904 DEBUG(D_receive) debug_printf("Invalid RCPT option: %s : %s\n", name, value);
4911 /* Apply SMTP rewriting then extract the working address. Don't allow "<>"
4912 as a recipient address */
4914 recipient = rewrite_existflags & rewrite_smtp
4915 ? rewrite_one(smtp_cmd_data, rewrite_smtp, NULL, FALSE, US"",
4916 global_rewrite_rules)
4919 if (!(recipient = parse_extract_address(recipient, &errmess, &start, &end,
4920 &recipient_domain, FALSE)))
4922 done = synprot_error(L_smtp_syntax_error, 501, smtp_cmd_data, errmess);
4927 /* If the recipient address is unqualified, reject it, unless this is a
4928 locally generated message. However, unqualified addresses are permitted
4929 from a configured list of hosts and nets - typically when behaving as
4930 MUAs rather than MTAs. Sad that SMTP is used for both types of traffic,
4931 really. The flag is set at the start of the SMTP connection.
4933 RFC 1123 talks about supporting "the reserved mailbox postmaster"; I always
4934 assumed this meant "reserved local part", but the revision of RFC 821 and
4935 friends now makes it absolutely clear that it means *mailbox*. Consequently
4936 we must always qualify this address, regardless. */
4938 if (!recipient_domain)
4939 if (!(recipient_domain = qualify_recipient(&recipient, smtp_cmd_data,
4946 /* Check maximum allowed */
4948 if (rcpt_count > recipients_max && recipients_max > 0)
4950 if (recipients_max_reject)
4953 smtp_printf("552 too many recipients\r\n", FALSE);
4955 log_write(0, LOG_MAIN|LOG_REJECT, "too many recipients: message "
4956 "rejected: sender=<%s> %s", sender_address, host_and_ident(TRUE));
4961 smtp_printf("452 too many recipients\r\n", FALSE);
4963 log_write(0, LOG_MAIN|LOG_REJECT, "too many recipients: excess "
4964 "temporarily rejected: sender=<%s> %s", sender_address,
4965 host_and_ident(TRUE));
4972 /* If we have passed the threshold for rate limiting, apply the current
4973 delay, and update it for next time, provided this is a limited host. */
4975 if (rcpt_count > smtp_rlr_threshold &&
4976 verify_check_host(&smtp_ratelimit_hosts) == OK)
4978 DEBUG(D_receive) debug_printf("rate limit RCPT: delay %.3g sec\n",
4979 smtp_delay_rcpt/1000.0);
4980 millisleep((int)smtp_delay_rcpt);
4981 smtp_delay_rcpt *= smtp_rlr_factor;
4982 if (smtp_delay_rcpt > (double)smtp_rlr_limit)
4983 smtp_delay_rcpt = (double)smtp_rlr_limit;
4986 /* If the MAIL ACL discarded all the recipients, we bypass ACL checking
4987 for them. Otherwise, check the access control list for this recipient. As
4988 there may be a delay in this, re-check for a synchronization error
4989 afterwards, unless pipelining was advertised. */
4991 if (recipients_discarded)
4994 if ( (rc = acl_check(ACL_WHERE_RCPT, recipient, acl_smtp_rcpt, &user_msg,
4996 && !pipelining_advertised && !check_sync())
4999 /* The ACL was happy */
5003 BOOL more = pipeline_response();
5006 smtp_user_msg(US"250", user_msg);
5008 smtp_printf("250 Accepted\r\n", more);
5009 receive_add_recipient(recipient, -1);
5011 /* Set the dsn flags in the recipients_list */
5012 recipients_list[recipients_count-1].orcpt = orcpt;
5013 recipients_list[recipients_count-1].dsn_flags = flags;
5015 DEBUG(D_receive) debug_printf("DSN: orcpt: %s flags: %d\n",
5016 recipients_list[recipients_count-1].orcpt,
5017 recipients_list[recipients_count-1].dsn_flags);
5020 /* The recipient was discarded */
5022 else if (rc == DISCARD)
5025 smtp_user_msg(US"250", user_msg);
5027 smtp_printf("250 Accepted\r\n", FALSE);
5030 log_write(0, LOG_MAIN|LOG_REJECT, "%s F=<%s> RCPT %s: "
5031 "discarded by %s ACL%s%s", host_and_ident(TRUE),
5032 sender_address_unrewritten? sender_address_unrewritten : sender_address,
5033 smtp_cmd_argument, recipients_discarded? "MAIL" : "RCPT",
5034 log_msg ? US": " : US"", log_msg ? log_msg : US"");
5037 /* Either the ACL failed the address, or it was deferred. */
5041 if (rc == FAIL) rcpt_fail_count++; else rcpt_defer_count++;
5042 done = smtp_handle_acl_fail(ACL_WHERE_RCPT, rc, user_msg, log_msg);
5047 /* The DATA command is legal only if it follows successful MAIL FROM
5048 and RCPT TO commands. However, if pipelining is advertised, a bad DATA is
5049 not counted as a protocol error if it follows RCPT (which must have been
5050 rejected if there are no recipients.) This function is complete when a
5051 valid DATA command is encountered.
5053 Note concerning the code used: RFC 2821 says this:
5055 - If there was no MAIL, or no RCPT, command, or all such commands
5056 were rejected, the server MAY return a "command out of sequence"
5057 (503) or "no valid recipients" (554) reply in response to the
5060 The example in the pipelining RFC 2920 uses 554, but I use 503 here
5061 because it is the same whether pipelining is in use or not.
5063 If all the RCPT commands that precede DATA provoked the same error message
5064 (often indicating some kind of system error), it is helpful to include it
5065 with the DATA rejection (an idea suggested by Tony Finch). */
5072 if (chunking_state != CHUNKING_OFFERED)
5074 done = synprot_error(L_smtp_protocol_error, 503, NULL,
5075 US"BDAT command used when CHUNKING not advertised");
5079 /* grab size, endmarker */
5081 if (sscanf(CS smtp_cmd_data, "%u %n", &chunking_datasize, &n) < 1)
5083 done = synprot_error(L_smtp_protocol_error, 501, NULL,
5084 US"missing size for BDAT command");
5087 chunking_state = strcmpic(smtp_cmd_data+n, US"LAST") == 0
5088 ? CHUNKING_LAST : CHUNKING_ACTIVE;
5089 chunking_data_left = chunking_datasize;
5090 DEBUG(D_receive) debug_printf("chunking state %d, %d bytes\n",
5091 (int)chunking_state, chunking_data_left);
5093 lwr_receive_getc = receive_getc;
5094 lwr_receive_getbuf = receive_getbuf;
5095 lwr_receive_ungetc = receive_ungetc;
5096 receive_getc = bdat_getc;
5097 receive_ungetc = bdat_ungetc;
5105 DATA_BDAT: /* Common code for DATA and BDAT */
5106 if (!discarded && recipients_count <= 0)
5108 if (rcpt_smtp_response_same && rcpt_smtp_response != NULL)
5110 uschar *code = US"503";
5111 int len = Ustrlen(rcpt_smtp_response);
5112 smtp_respond(code, 3, FALSE, US"All RCPT commands were rejected with "
5114 /* Responses from smtp_printf() will have \r\n on the end */
5115 if (len > 2 && rcpt_smtp_response[len-2] == '\r')
5116 rcpt_smtp_response[len-2] = 0;
5117 smtp_respond(code, 3, FALSE, rcpt_smtp_response);
5119 if (pipelining_advertised && last_was_rcpt)
5120 smtp_printf("503 Valid RCPT command must precede %s\r\n", FALSE,
5121 smtp_names[smtp_connection_had[smtp_ch_index-1]]);
5123 done = synprot_error(L_smtp_protocol_error, 503, NULL,
5124 smtp_connection_had[smtp_ch_index-1] == SCH_DATA
5125 ? US"valid RCPT command must precede DATA"
5126 : US"valid RCPT command must precede BDAT");
5128 if (chunking_state > CHUNKING_OFFERED)
5133 if (toomany && recipients_max_reject)
5135 sender_address = NULL; /* This will allow a new MAIL without RSET */
5136 sender_address_unrewritten = NULL;
5137 smtp_printf("554 Too many recipients\r\n", FALSE);
5141 if (chunking_state > CHUNKING_OFFERED)
5142 rc = OK; /* No predata ACL or go-ahead output for BDAT */
5145 /* If there is an ACL, re-check the synchronization afterwards, since the
5146 ACL may have delayed. To handle cutthrough delivery enforce a dummy call
5147 to get the DATA command sent. */
5149 if (acl_smtp_predata == NULL && cutthrough.fd < 0)
5153 uschar * acl = acl_smtp_predata ? acl_smtp_predata : US"accept";
5154 enable_dollar_recipients = TRUE;
5155 rc = acl_check(ACL_WHERE_PREDATA, NULL, acl, &user_msg,
5157 enable_dollar_recipients = FALSE;
5158 if (rc == OK && !check_sync())
5162 { /* Either the ACL failed the address, or it was deferred. */
5163 done = smtp_handle_acl_fail(ACL_WHERE_PREDATA, rc, user_msg, log_msg);
5169 smtp_user_msg(US"354", user_msg);
5172 "354 Enter message, ending with \".\" on a line by itself\r\n", FALSE);
5176 if (smtp_in) /* all ACKs needed to ramp window up for bulk data */
5177 (void) setsockopt(fileno(smtp_in), IPPROTO_TCP, TCP_QUICKACK,
5178 US &on, sizeof(on));
5181 message_ended = END_NOTENDED; /* Indicate in middle of data */
5192 if (!(address = parse_extract_address(smtp_cmd_data, &errmess,
5193 &start, &end, &recipient_domain, FALSE)))
5195 smtp_printf("501 %s\r\n", FALSE, errmess);
5199 if (!recipient_domain)
5200 if (!(recipient_domain = qualify_recipient(&address, smtp_cmd_data,
5204 if ((rc = acl_check(ACL_WHERE_VRFY, address, acl_smtp_vrfy,
5205 &user_msg, &log_msg)) != OK)
5206 done = smtp_handle_acl_fail(ACL_WHERE_VRFY, rc, user_msg, log_msg);
5210 address_item * addr = deliver_make_addr(address, FALSE);
5212 switch(verify_address(addr, NULL, vopt_is_recipient | vopt_qualify, -1,
5213 -1, -1, NULL, NULL, NULL))
5216 s = string_sprintf("250 <%s> is deliverable", address);
5220 s = (addr->user_message != NULL)?
5221 string_sprintf("451 <%s> %s", address, addr->user_message) :
5222 string_sprintf("451 Cannot resolve <%s> at this time", address);
5226 s = (addr->user_message != NULL)?
5227 string_sprintf("550 <%s> %s", address, addr->user_message) :
5228 string_sprintf("550 <%s> is not deliverable", address);
5229 log_write(0, LOG_MAIN, "VRFY failed for %s %s",
5230 smtp_cmd_argument, host_and_ident(TRUE));
5234 smtp_printf("%s\r\n", FALSE, s);
5242 rc = acl_check(ACL_WHERE_EXPN, NULL, acl_smtp_expn, &user_msg, &log_msg);
5244 done = smtp_handle_acl_fail(ACL_WHERE_EXPN, rc, user_msg, log_msg);
5247 BOOL save_log_testing_mode = log_testing_mode;
5248 address_test_mode = log_testing_mode = TRUE;
5249 (void) verify_address(deliver_make_addr(smtp_cmd_data, FALSE),
5250 smtp_out, vopt_is_recipient | vopt_qualify | vopt_expn, -1, -1, -1,
5252 address_test_mode = FALSE;
5253 log_testing_mode = save_log_testing_mode; /* true for -bh */
5262 if (!tls_advertised)
5264 done = synprot_error(L_smtp_protocol_error, 503, NULL,
5265 US"STARTTLS command used when not advertised");
5269 /* Apply an ACL check if one is defined */
5271 if ( acl_smtp_starttls
5272 && (rc = acl_check(ACL_WHERE_STARTTLS, NULL, acl_smtp_starttls,
5273 &user_msg, &log_msg)) != OK
5276 done = smtp_handle_acl_fail(ACL_WHERE_STARTTLS, rc, user_msg, log_msg);
5280 /* RFC 2487 is not clear on when this command may be sent, though it
5281 does state that all information previously obtained from the client
5282 must be discarded if a TLS session is started. It seems reasonable to
5283 do an implied RSET when STARTTLS is received. */
5285 incomplete_transaction_log(US"STARTTLS");
5286 cancel_cutthrough_connection(TRUE, US"STARTTLS received");
5287 smtp_reset(reset_point);
5289 cmd_list[CMD_LIST_STARTTLS].is_mail_cmd = FALSE;
5291 /* There's an attack where more data is read in past the STARTTLS command
5292 before TLS is negotiated, then assumed to be part of the secure session
5293 when used afterwards; we use segregated input buffers, so are not
5294 vulnerable, but we want to note when it happens and, for sheer paranoia,
5295 ensure that the buffer is "wiped".
5296 Pipelining sync checks will normally have protected us too, unless disabled
5297 by configuration. */
5299 if (receive_smtp_buffered())
5302 debug_printf("Non-empty input buffer after STARTTLS; naive attack?\n");
5303 if (tls_in.active < 0)
5304 smtp_inend = smtp_inptr = smtp_inbuffer;
5305 /* and if TLS is already active, tls_server_start() should fail */
5308 /* There is nothing we value in the input buffer and if TLS is successfully
5309 negotiated, we won't use this buffer again; if TLS fails, we'll just read
5310 fresh content into it. The buffer contains arbitrary content from an
5311 untrusted remote source; eg: NOOP <shellcode>\r\nSTARTTLS\r\n
5312 It seems safest to just wipe away the content rather than leave it as a
5313 target to jump to. */
5315 memset(smtp_inbuffer, 0, IN_BUFFER_SIZE);
5317 /* Attempt to start up a TLS session, and if successful, discard all
5318 knowledge that was obtained previously. At least, that's what the RFC says,
5319 and that's what happens by default. However, in order to work round YAEB,
5320 there is an option to remember the esmtp state. Sigh.
5322 We must allow for an extra EHLO command and an extra AUTH command after
5323 STARTTLS that don't add to the nonmail command count. */
5326 if ((rc = tls_server_start(tls_require_ciphers, &s)) == OK)
5328 if (!tls_remember_esmtp)
5329 helo_seen = esmtp = auth_advertised = pipelining_advertised = FALSE;
5330 cmd_list[CMD_LIST_EHLO].is_mail_cmd = TRUE;
5331 cmd_list[CMD_LIST_AUTH].is_mail_cmd = TRUE;
5332 cmd_list[CMD_LIST_TLS_AUTH].is_mail_cmd = TRUE;
5333 if (sender_helo_name != NULL)
5335 store_free(sender_helo_name);
5336 sender_helo_name = NULL;
5337 host_build_sender_fullhost(); /* Rebuild */
5338 set_process_info("handling incoming TLS connection from %s",
5339 host_and_ident(FALSE));
5342 (sender_host_address ? protocols : protocols_local)
5344 ? pextend + (sender_host_authenticated ? pauthed : 0)
5346 + (tls_in.active >= 0 ? pcrpted : 0)
5349 sender_host_authenticated = NULL;
5350 authenticated_id = NULL;
5351 sync_cmd_limit = NON_SYNC_CMD_NON_PIPELINING;
5352 DEBUG(D_tls) debug_printf("TLS active\n");
5353 break; /* Successful STARTTLS */
5356 (void) smtp_log_tls_fail(s);
5358 /* Some local configuration problem was discovered before actually trying
5359 to do a TLS handshake; give a temporary error. */
5363 smtp_printf("454 TLS currently unavailable\r\n", FALSE);
5367 /* Hard failure. Reject everything except QUIT or closed connection. One
5368 cause for failure is a nested STARTTLS, in which case tls_in.active remains
5369 set, but we must still reject all incoming commands. */
5371 DEBUG(D_tls) debug_printf("TLS failed to start\n");
5372 while (done <= 0) switch(smtp_read_command(FALSE, GETC_BUFFER_UNLIMITED))
5375 log_write(L_smtp_connection, LOG_MAIN, "%s closed by EOF",
5376 smtp_get_connection_info());
5377 smtp_notquit_exit(US"tls-failed", NULL, NULL);
5381 /* It is perhaps arguable as to which exit ACL should be called here,
5382 but as it is probably a situation that almost never arises, it
5383 probably doesn't matter. We choose to call the real QUIT ACL, which in
5384 some sense is perhaps "right". */
5389 && ((rc = acl_check(ACL_WHERE_QUIT, NULL, acl_smtp_quit, &user_msg,
5390 &log_msg)) == ERROR))
5391 log_write(0, LOG_MAIN|LOG_PANIC, "ACL for QUIT returned ERROR: %s",
5394 smtp_respond(US"221", 3, TRUE, user_msg);
5396 smtp_printf("221 %s closing connection\r\n", FALSE, smtp_active_hostname);
5397 log_write(L_smtp_connection, LOG_MAIN, "%s closed by QUIT",
5398 smtp_get_connection_info());
5403 smtp_printf("554 Security failure\r\n", FALSE);
5406 tls_close(TRUE, TRUE);
5411 /* The ACL for QUIT is provided for gathering statistical information or
5412 similar; it does not affect the response code, but it can supply a custom
5416 smtp_quit_handler(&user_msg, &log_msg);
5422 smtp_rset_handler();
5423 cancel_cutthrough_connection(TRUE, US"RSET received");
5424 smtp_reset(reset_point);
5431 smtp_printf("250 OK\r\n", FALSE);
5435 /* Show ETRN/EXPN/VRFY if there's an ACL for checking hosts; if actually
5436 used, a check will be done for permitted hosts. Show STARTTLS only if not
5437 already in a TLS session and if it would be advertised in the EHLO
5442 smtp_printf("214-Commands supported:\r\n", TRUE);
5446 Ustrcat(buffer, " AUTH");
5448 if (tls_in.active < 0 &&
5449 verify_check_host(&tls_advertise_hosts) != FAIL)
5450 Ustrcat(buffer, " STARTTLS");
5452 Ustrcat(buffer, " HELO EHLO MAIL RCPT DATA BDAT");
5453 Ustrcat(buffer, " NOOP QUIT RSET HELP");
5454 if (acl_smtp_etrn != NULL) Ustrcat(buffer, " ETRN");
5455 if (acl_smtp_expn != NULL) Ustrcat(buffer, " EXPN");
5456 if (acl_smtp_vrfy != NULL) Ustrcat(buffer, " VRFY");
5457 smtp_printf("214%s\r\n", FALSE, buffer);
5463 incomplete_transaction_log(US"connection lost");
5464 smtp_notquit_exit(US"connection-lost", US"421",
5465 US"%s lost input connection", smtp_active_hostname);
5467 /* Don't log by default unless in the middle of a message, as some mailers
5468 just drop the call rather than sending QUIT, and it clutters up the logs.
5471 if (sender_address || recipients_count > 0)
5472 log_write(L_lost_incoming_connection, LOG_MAIN,
5473 "unexpected %s while reading SMTP command from %s%s%s D=%s",
5474 sender_host_unknown ? "EOF" : "disconnection",
5475 tcp_in_fastopen && !tcp_in_fastopen_logged ? US"TFO " : US"",
5476 host_and_ident(FALSE), smtp_read_error,
5477 string_timesince(&smtp_connection_start)
5481 log_write(L_smtp_connection, LOG_MAIN, "%s %slost%s D=%s",
5482 smtp_get_connection_info(),
5483 tcp_in_fastopen && !tcp_in_fastopen_logged ? US"TFO " : US"",
5485 string_timesince(&smtp_connection_start)
5494 if (sender_address != NULL)
5496 done = synprot_error(L_smtp_protocol_error, 503, NULL,
5497 US"ETRN is not permitted inside a transaction");
5501 log_write(L_etrn, LOG_MAIN, "ETRN %s received from %s", smtp_cmd_argument,
5502 host_and_ident(FALSE));
5504 if ((rc = acl_check(ACL_WHERE_ETRN, NULL, acl_smtp_etrn,
5505 &user_msg, &log_msg)) != OK)
5507 done = smtp_handle_acl_fail(ACL_WHERE_ETRN, rc, user_msg, log_msg);
5511 /* Compute the serialization key for this command. */
5513 etrn_serialize_key = string_sprintf("etrn-%s\n", smtp_cmd_data);
5515 /* If a command has been specified for running as a result of ETRN, we
5516 permit any argument to ETRN. If not, only the # standard form is permitted,
5517 since that is strictly the only kind of ETRN that can be implemented
5518 according to the RFC. */
5520 if (smtp_etrn_command != NULL)
5524 etrn_command = smtp_etrn_command;
5525 deliver_domain = smtp_cmd_data;
5526 rc = transport_set_up_command(&argv, smtp_etrn_command, TRUE, 0, NULL,
5527 US"ETRN processing", &error);
5528 deliver_domain = NULL;
5531 log_write(0, LOG_MAIN|LOG_PANIC, "failed to set up ETRN command: %s",
5533 smtp_printf("458 Internal failure\r\n", FALSE);
5538 /* Else set up to call Exim with the -R option. */
5542 if (*smtp_cmd_data++ != '#')
5544 done = synprot_error(L_smtp_syntax_error, 501, NULL,
5545 US"argument must begin with #");
5548 etrn_command = US"exim -R";
5549 argv = CUSS child_exec_exim(CEE_RETURN_ARGV, TRUE, NULL, TRUE,
5550 *queue_name ? 4 : 2,
5551 US"-R", smtp_cmd_data,
5552 US"-MCG", queue_name);
5555 /* If we are host-testing, don't actually do anything. */
5561 debug_printf("ETRN command is: %s\n", etrn_command);
5562 debug_printf("ETRN command execution skipped\n");
5564 if (user_msg == NULL) smtp_printf("250 OK\r\n", FALSE);
5565 else smtp_user_msg(US"250", user_msg);
5570 /* If ETRN queue runs are to be serialized, check the database to
5571 ensure one isn't already running. */
5573 if (smtp_etrn_serialize && !enq_start(etrn_serialize_key, 1))
5575 smtp_printf("458 Already processing %s\r\n", FALSE, smtp_cmd_data);
5579 /* Fork a child process and run the command. We don't want to have to
5580 wait for the process at any point, so set SIGCHLD to SIG_IGN before
5581 forking. It should be set that way anyway for external incoming SMTP,
5582 but we save and restore to be tidy. If serialization is required, we
5583 actually run the command in yet another process, so we can wait for it
5584 to complete and then remove the serialization lock. */
5586 oldsignal = signal(SIGCHLD, SIG_IGN);
5588 if ((pid = fork()) == 0)
5590 smtp_input = FALSE; /* This process is not associated with the */
5591 (void)fclose(smtp_in); /* SMTP call any more. */
5592 (void)fclose(smtp_out);
5594 signal(SIGCHLD, SIG_DFL); /* Want to catch child */
5596 /* If not serializing, do the exec right away. Otherwise, fork down
5597 into another process. */
5599 if (!smtp_etrn_serialize || (pid = fork()) == 0)
5601 DEBUG(D_exec) debug_print_argv(argv);
5602 exim_nullstd(); /* Ensure std{in,out,err} exist */
5603 execv(CS argv[0], (char *const *)argv);
5604 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "exec of \"%s\" (ETRN) failed: %s",
5605 etrn_command, strerror(errno));
5606 _exit(EXIT_FAILURE); /* paranoia */
5609 /* Obey this if smtp_serialize and the 2nd fork yielded non-zero. That
5610 is, we are in the first subprocess, after forking again. All we can do
5611 for a failing fork is to log it. Otherwise, wait for the 2nd process to
5612 complete, before removing the serialization. */
5615 log_write(0, LOG_MAIN|LOG_PANIC, "2nd fork for serialized ETRN "
5616 "failed: %s", strerror(errno));
5620 DEBUG(D_any) debug_printf("waiting for serialized ETRN process %d\n",
5622 (void)wait(&status);
5623 DEBUG(D_any) debug_printf("serialized ETRN process %d ended\n",
5627 enq_end(etrn_serialize_key);
5628 _exit(EXIT_SUCCESS);
5631 /* Back in the top level SMTP process. Check that we started a subprocess
5632 and restore the signal state. */
5636 log_write(0, LOG_MAIN|LOG_PANIC, "fork of process for ETRN failed: %s",
5638 smtp_printf("458 Unable to fork process\r\n", FALSE);
5639 if (smtp_etrn_serialize) enq_end(etrn_serialize_key);
5643 if (user_msg == NULL) smtp_printf("250 OK\r\n", FALSE);
5644 else smtp_user_msg(US"250", user_msg);
5647 signal(SIGCHLD, oldsignal);
5652 done = synprot_error(L_smtp_syntax_error, 501, NULL,
5653 US"unexpected argument data");
5657 /* This currently happens only for NULLs, but could be extended. */
5660 done = synprot_error(L_smtp_syntax_error, 0, NULL, /* Just logs */
5661 US"NULL character(s) present (shown as '?')");
5662 smtp_printf("501 NULL characters are not allowed in SMTP commands\r\n", FALSE);
5668 if (smtp_inend >= smtp_inbuffer + IN_BUFFER_SIZE)
5669 smtp_inend = smtp_inbuffer + IN_BUFFER_SIZE - 1;
5670 c = smtp_inend - smtp_inptr;
5671 if (c > 150) c = 150;
5673 incomplete_transaction_log(US"sync failure");
5674 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP protocol synchronization error "
5675 "(next input sent too soon: pipelining was%s advertised): "
5676 "rejected \"%s\" %s next input=\"%s\"",
5677 pipelining_advertised? "" : " not",
5678 smtp_cmd_buffer, host_and_ident(TRUE),
5679 string_printing(smtp_inptr));
5680 smtp_notquit_exit(US"synchronization-error", US"554",
5681 US"SMTP synchronization error");
5682 done = 1; /* Pretend eof - drops connection */
5686 case TOO_MANY_NONMAIL_CMD:
5687 s = smtp_cmd_buffer;
5688 while (*s != 0 && !isspace(*s)) s++;
5689 incomplete_transaction_log(US"too many non-mail commands");
5690 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
5691 "nonmail commands (last was \"%.*s\")", host_and_ident(FALSE),
5692 (int)(s - smtp_cmd_buffer), smtp_cmd_buffer);
5693 smtp_notquit_exit(US"bad-commands", US"554", US"Too many nonmail commands");
5694 done = 1; /* Pretend eof - drops connection */
5697 #ifdef SUPPORT_PROXY
5698 case PROXY_FAIL_IGNORE_CMD:
5699 smtp_printf("503 Command refused, required Proxy negotiation failed\r\n", FALSE);
5704 if (unknown_command_count++ >= smtp_max_unknown_commands)
5706 log_write(L_smtp_syntax_error, LOG_MAIN,
5707 "SMTP syntax error in \"%s\" %s %s",
5708 string_printing(smtp_cmd_buffer), host_and_ident(TRUE),
5709 US"unrecognized command");
5710 incomplete_transaction_log(US"unrecognized command");
5711 smtp_notquit_exit(US"bad-commands", US"500",
5712 US"Too many unrecognized commands");
5714 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
5715 "unrecognized commands (last was \"%s\")", host_and_ident(FALSE),
5716 string_printing(smtp_cmd_buffer));
5719 done = synprot_error(L_smtp_syntax_error, 500, NULL,
5720 US"unrecognized command");
5724 /* This label is used by goto's inside loops that want to break out to
5725 the end of the command-processing loop. */
5728 last_was_rej_mail = was_rej_mail; /* Remember some last commands for */
5729 last_was_rcpt = was_rcpt; /* protocol error handling */
5733 return done - 2; /* Convert yield values */
5738 /* End of smtp_in.c */