1 /*************************************************
2 * Exim - an Internet mail transport agent *
3 *************************************************/
5 /* Copyright (c) University of Cambridge 1995 - 2018 */
6 /* See the file NOTICE for conditions of use and distribution. */
8 /* Functions for handling an incoming SMTP call. */
15 /* Initialize for TCP wrappers if so configured. It appears that the macro
16 HAVE_IPV6 is used in some versions of the tcpd.h header, so we unset it before
17 including that header, and restore its value afterwards. */
19 #ifdef USE_TCP_WRAPPERS
22 #define EXIM_HAVE_IPV6
28 #define HAVE_IPV6 TRUE
31 int allow_severity = LOG_INFO;
32 int deny_severity = LOG_NOTICE;
33 uschar *tcp_wrappers_name;
37 /* Size of buffer for reading SMTP commands. We used to use 512, as defined
38 by RFC 821. However, RFC 1869 specifies that this must be increased for SMTP
39 commands that accept arguments, and this in particular applies to AUTH, where
40 the data can be quite long. More recently this value was 2048 in Exim;
41 however, RFC 4954 (circa 2007) recommends 12288 bytes to handle AUTH. Clients
42 such as Thunderbird will send an AUTH with an initial-response for GSSAPI.
43 The maximum size of a Kerberos ticket under Windows 2003 is 12000 bytes, and
44 we need room to handle large base64-encoded AUTHs for GSSAPI.
47 #define SMTP_CMD_BUFFER_SIZE 16384
49 /* Size of buffer for reading SMTP incoming packets */
51 #define IN_BUFFER_SIZE 8192
53 /* Structure for SMTP command list */
60 short int is_mail_cmd;
63 /* Codes for identifying commands. We order them so that those that come first
64 are those for which synchronization is always required. Checking this can help
68 /* These commands are required to be synchronized, i.e. to be the last in a
69 block of commands when pipelining. */
71 HELO_CMD, EHLO_CMD, DATA_CMD, /* These are listed in the pipelining */
72 VRFY_CMD, EXPN_CMD, NOOP_CMD, /* RFC as requiring synchronization */
73 ETRN_CMD, /* This by analogy with TURN from the RFC */
74 STARTTLS_CMD, /* Required by the STARTTLS RFC */
75 TLS_AUTH_CMD, /* auto-command at start of SSL */
77 /* This is a dummy to identify the non-sync commands when pipelining */
79 NON_SYNC_CMD_PIPELINING,
81 /* These commands need not be synchronized when pipelining */
83 MAIL_CMD, RCPT_CMD, RSET_CMD,
85 /* This is a dummy to identify the non-sync commands when not pipelining */
87 NON_SYNC_CMD_NON_PIPELINING,
89 /* RFC3030 section 2: "After all MAIL and RCPT responses are collected and
90 processed the message is sent using a series of BDAT commands"
91 implies that BDAT should be synchronized. However, we see Google, at least,
92 sending MAIL,RCPT,BDAT-LAST in a single packet, clearly not waiting for
93 processing of the RCPT response(s). We shall do the same, and not require
94 synch for BDAT. Worse, as the chunk may (very likely will) follow the
95 command-header in the same packet we cannot do the usual "is there any
96 follow-on data after the command line" even for non-pipeline mode.
97 So we'll need an explicit check after reading the expected chunk amount
98 when non-pipe, before sending the ACK. */
102 /* I have been unable to find a statement about the use of pipelining
103 with AUTH, so to be on the safe side it is here, though I kind of feel
104 it should be up there with the synchronized commands. */
108 /* I'm not sure about these, but I don't think they matter. */
113 PROXY_FAIL_IGNORE_CMD,
116 /* These are specials that don't correspond to actual commands */
118 EOF_CMD, OTHER_CMD, BADARG_CMD, BADCHAR_CMD, BADSYN_CMD,
119 TOO_MANY_NONMAIL_CMD };
122 /* This is a convenience macro for adding the identity of an SMTP command
123 to the circular buffer that holds a list of the last n received. */
126 smtp_connection_had[smtp_ch_index++] = n; \
127 if (smtp_ch_index >= SMTP_HBUFF_SIZE) smtp_ch_index = 0
130 /*************************************************
131 * Local static variables *
132 *************************************************/
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, FALSE },
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 */
368 if (!smtp_enforce_sync || !sender_host_address || sender_host_notsocket)
371 return wouldblock_reading();
375 /* If there's input waiting (and we're doing pipelineing) then we can pipeline
376 a reponse with the one following. */
379 pipeline_response(void)
381 if ( !smtp_enforce_sync || !sender_host_address
382 || sender_host_notsocket || !pipelining_advertised)
385 return !wouldblock_reading();
390 /*************************************************
391 * Log incomplete transactions *
392 *************************************************/
394 /* This function is called after a transaction has been aborted by RSET, QUIT,
395 connection drops or other errors. It logs the envelope information received
396 so far in order to preserve address verification attempts.
398 Argument: string to indicate what aborted the transaction
403 incomplete_transaction_log(uschar *what)
405 if (sender_address == NULL || /* No transaction in progress */
406 !LOGGING(smtp_incomplete_transaction))
409 /* Build list of recipients for logging */
411 if (recipients_count > 0)
414 raw_recipients = store_get(recipients_count * sizeof(uschar *));
415 for (i = 0; i < recipients_count; i++)
416 raw_recipients[i] = recipients_list[i].address;
417 raw_recipients_count = recipients_count;
420 log_write(L_smtp_incomplete_transaction, LOG_MAIN|LOG_SENDER|LOG_RECIPIENTS,
421 "%s incomplete transaction (%s)", host_and_ident(TRUE), what);
427 /* Refill the buffer, and notify DKIM verification code.
428 Return false for error or EOF.
432 smtp_refill(unsigned lim)
435 if (!smtp_out) return FALSE;
437 if (smtp_receive_timeout > 0) alarm(smtp_receive_timeout);
439 /* Limit amount read, so non-message data is not fed to DKIM.
440 Take care to not touch the safety NUL at the end of the buffer. */
442 rc = read(fileno(smtp_in), smtp_inbuffer, MIN(IN_BUFFER_SIZE-1, lim));
447 /* Must put the error text in fixed store, because this might be during
448 header reading, where it releases unused store above the header. */
451 smtp_had_error = save_errno;
452 smtp_read_error = string_copy_malloc(
453 string_sprintf(" (error: %s)", strerror(save_errno)));
455 else smtp_had_eof = 1;
459 dkim_exim_verify_feed(smtp_inbuffer, rc);
461 smtp_inend = smtp_inbuffer + rc;
462 smtp_inptr = smtp_inbuffer;
466 /*************************************************
467 * SMTP version of getc() *
468 *************************************************/
470 /* This gets the next byte from the SMTP input buffer. If the buffer is empty,
471 it flushes the output, and refills the buffer, with a timeout. The signal
472 handler is set appropriately by the calling function. This function is not used
473 after a connection has negotiated itself into an TLS/SSL state.
475 Arguments: lim Maximum amount to read/buffer
476 Returns: the next character or EOF
480 smtp_getc(unsigned lim)
482 if (smtp_inptr >= smtp_inend)
483 if (!smtp_refill(lim))
485 return *smtp_inptr++;
489 smtp_getbuf(unsigned * len)
494 if (smtp_inptr >= smtp_inend)
495 if (!smtp_refill(*len))
496 { *len = 0; return NULL; }
498 if ((size = smtp_inend - smtp_inptr) > *len) size = *len;
509 int n = smtp_inend - smtp_inptr;
511 dkim_exim_verify_feed(smtp_inptr, n);
516 /* Get a byte from the smtp input, in CHUNKING mode. Handle ack of the
517 previous BDAT chunk and getting new ones when we run out. Uses the
518 underlying smtp_getc or tls_getc both for that and for getting the
519 (buffered) data byte. EOD signals (an expected) no further data.
520 ERR signals a protocol error, and EOF a closed input stream.
522 Called from read_bdat_smtp() in receive.c for the message body, but also
523 by the headers read loop in receive_msg(); manipulates chunking_state
524 to handle the BDAT command/response.
525 Placed here due to the correlation with the above smtp_getc(), which it wraps,
526 and also by the need to do smtp command/response handling.
528 Arguments: lim (ignored)
529 Returns: the next character or ERR, EOD or EOF
533 bdat_getc(unsigned lim)
535 uschar * user_msg = NULL;
544 if (chunking_data_left > 0)
545 return lwr_receive_getc(chunking_data_left--);
547 receive_getc = lwr_receive_getc;
548 receive_getbuf = lwr_receive_getbuf;
549 receive_ungetc = lwr_receive_ungetc;
551 dkim_save = dkim_collect_input;
552 dkim_collect_input = FALSE;
555 /* Unless PIPELINING was offered, there should be no next command
556 until after we ack that chunk */
558 if (!pipelining_advertised && !check_sync())
560 unsigned n = smtp_inend - smtp_inptr;
563 incomplete_transaction_log(US"sync failure");
564 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP protocol synchronization error "
565 "(next input sent too soon: pipelining was not advertised): "
566 "rejected \"%s\" %s next input=\"%s\"%s",
567 smtp_cmd_buffer, host_and_ident(TRUE),
568 string_printing(string_copyn(smtp_inptr, n)),
569 smtp_inend - smtp_inptr > n ? "..." : "");
570 (void) synprot_error(L_smtp_protocol_error, 554, NULL,
571 US"SMTP synchronization error");
572 goto repeat_until_rset;
575 /* If not the last, ack the received chunk. The last response is delayed
576 until after the data ACL decides on it */
578 if (chunking_state == CHUNKING_LAST)
581 dkim_exim_verify_feed(NULL, 0); /* notify EOD */
586 smtp_printf("250 %u byte chunk received\r\n", FALSE, chunking_datasize);
587 chunking_state = CHUNKING_OFFERED;
588 DEBUG(D_receive) debug_printf("chunking state %d\n", (int)chunking_state);
590 /* Expect another BDAT cmd from input. RFC 3030 says nothing about
591 QUIT, RSET or NOOP but handling them seems obvious */
594 switch(smtp_read_command(TRUE, 1))
597 (void) synprot_error(L_smtp_protocol_error, 503, NULL,
598 US"only BDAT permissible after non-LAST BDAT");
601 switch(smtp_read_command(TRUE, 1))
603 case QUIT_CMD: smtp_quit_handler(&user_msg, &log_msg); /*FALLTHROUGH */
604 case EOF_CMD: return EOF;
605 case RSET_CMD: smtp_rset_handler(); return ERR;
606 default: if (synprot_error(L_smtp_protocol_error, 503, NULL,
607 US"only RSET accepted now") > 0)
609 goto repeat_until_rset;
613 smtp_quit_handler(&user_msg, &log_msg);
624 smtp_printf("250 OK\r\n", FALSE);
631 if (sscanf(CS smtp_cmd_data, "%u %n", &chunking_datasize, &n) < 1)
633 (void) synprot_error(L_smtp_protocol_error, 501, NULL,
634 US"missing size for BDAT command");
637 chunking_state = strcmpic(smtp_cmd_data+n, US"LAST") == 0
638 ? CHUNKING_LAST : CHUNKING_ACTIVE;
639 chunking_data_left = chunking_datasize;
640 DEBUG(D_receive) debug_printf("chunking state %d, %d bytes\n",
641 (int)chunking_state, chunking_data_left);
643 if (chunking_datasize == 0)
644 if (chunking_state == CHUNKING_LAST)
648 (void) synprot_error(L_smtp_protocol_error, 504, NULL,
649 US"zero size for BDAT command");
650 goto repeat_until_rset;
653 receive_getc = bdat_getc;
654 receive_getbuf = bdat_getbuf; /* r~getbuf is never actually used */
655 receive_ungetc = bdat_ungetc;
657 dkim_collect_input = dkim_save;
659 break; /* to top of main loop */
666 bdat_getbuf(unsigned * len)
670 if (chunking_data_left <= 0)
671 { *len = 0; return NULL; }
673 if (*len > chunking_data_left) *len = chunking_data_left;
674 buf = lwr_receive_getbuf(len); /* Either smtp_getbuf or tls_getbuf */
675 chunking_data_left -= *len;
680 bdat_flush_data(void)
682 while (chunking_data_left)
684 unsigned n = chunking_data_left;
685 if (!bdat_getbuf(&n)) break;
688 receive_getc = lwr_receive_getc;
689 receive_getbuf = lwr_receive_getbuf;
690 receive_ungetc = lwr_receive_ungetc;
692 if (chunking_state != CHUNKING_LAST)
694 chunking_state = CHUNKING_OFFERED;
695 DEBUG(D_receive) debug_printf("chunking state %d\n", (int)chunking_state);
702 /*************************************************
703 * SMTP version of ungetc() *
704 *************************************************/
706 /* Puts a character back in the input buffer. Only ever
712 Returns: the character
726 chunking_data_left++;
727 return lwr_receive_ungetc(ch);
732 /*************************************************
733 * SMTP version of feof() *
734 *************************************************/
736 /* Tests for a previous EOF
739 Returns: non-zero if the eof flag is set
751 /*************************************************
752 * SMTP version of ferror() *
753 *************************************************/
755 /* Tests for a previous read error, and returns with errno
756 restored to what it was when the error was detected.
759 Returns: non-zero if the error flag is set
765 errno = smtp_had_error;
766 return smtp_had_error;
771 /*************************************************
772 * Test for characters in the SMTP buffer *
773 *************************************************/
775 /* Used at the end of a message
784 return smtp_inptr < smtp_inend;
789 /*************************************************
790 * Write formatted string to SMTP channel *
791 *************************************************/
793 /* This is a separate function so that we don't have to repeat everything for
794 TLS support or debugging. It is global so that the daemon and the
795 authentication functions can use it. It does not return any error indication,
796 because major problems such as dropped connections won't show up till an output
797 flush for non-TLS connections. The smtp_fflush() function is available for
798 checking that: for convenience, TLS output errors are remembered here so that
799 they are also picked up later by smtp_fflush().
803 more further data expected
804 ... optional arguments
810 smtp_printf(const char *format, BOOL more, ...)
815 smtp_vprintf(format, more, ap);
819 /* This is split off so that verify.c:respond_printf() can, in effect, call
820 smtp_printf(), bearing in mind that in C a vararg function can't directly
821 call another vararg function, only a function which accepts a va_list. */
824 smtp_vprintf(const char *format, BOOL more, va_list ap)
828 yield = string_vformat(big_buffer, big_buffer_size, format, ap);
832 void *reset_point = store_get(0);
833 uschar *msg_copy, *cr, *end;
834 msg_copy = string_copy(big_buffer);
835 end = msg_copy + Ustrlen(msg_copy);
836 while ((cr = Ustrchr(msg_copy, '\r')) != NULL) /* lose CRs */
837 memmove(cr, cr + 1, (end--) - cr);
838 debug_printf("SMTP>> %s", msg_copy);
839 store_reset(reset_point);
844 log_write(0, LOG_MAIN|LOG_PANIC, "string too large in smtp_printf()");
845 smtp_closedown(US"Unexpected error");
846 exim_exit(EXIT_FAILURE, NULL);
849 /* If this is the first output for a (non-batch) RCPT command, see if all RCPTs
850 have had the same. Note: this code is also present in smtp_respond(). It would
851 be tidier to have it only in one place, but when it was added, it was easier to
852 do it that way, so as not to have to mess with the code for the RCPT command,
853 which sometimes uses smtp_printf() and sometimes smtp_respond(). */
855 if (rcpt_in_progress)
857 if (rcpt_smtp_response == NULL)
858 rcpt_smtp_response = string_copy(big_buffer);
859 else if (rcpt_smtp_response_same &&
860 Ustrcmp(rcpt_smtp_response, big_buffer) != 0)
861 rcpt_smtp_response_same = FALSE;
862 rcpt_in_progress = FALSE;
865 /* Now write the string */
868 if (tls_in.active >= 0)
870 if (tls_write(TRUE, big_buffer, Ustrlen(big_buffer), more) < 0)
871 smtp_write_error = -1;
876 if (fprintf(smtp_out, "%s", big_buffer) < 0) smtp_write_error = -1;
881 /*************************************************
882 * Flush SMTP out and check for error *
883 *************************************************/
885 /* This function isn't currently used within Exim (it detects errors when it
886 tries to read the next SMTP input), but is available for use in local_scan().
887 For non-TLS connections, it flushes the output and checks for errors. For
888 TLS-connections, it checks for a previously-detected TLS write error.
891 Returns: 0 for no error; -1 after an error
897 if (tls_in.active < 0 && fflush(smtp_out) != 0) smtp_write_error = -1;
898 return smtp_write_error;
903 /*************************************************
904 * SMTP command read timeout *
905 *************************************************/
907 /* Signal handler for timing out incoming SMTP commands. This attempts to
910 Argument: signal number (SIGALRM)
915 command_timeout_handler(int sig)
917 sig = sig; /* Keep picky compilers happy */
918 log_write(L_lost_incoming_connection,
919 LOG_MAIN, "SMTP command timeout on%s connection from %s",
920 (tls_in.active >= 0)? " TLS" : "",
921 host_and_ident(FALSE));
922 if (smtp_batched_input)
923 moan_smtp_batch(NULL, "421 SMTP command timeout"); /* Does not return */
924 smtp_notquit_exit(US"command-timeout", US"421",
925 US"%s: SMTP command timeout - closing connection", smtp_active_hostname);
926 exim_exit(EXIT_FAILURE, US"receiving");
931 /*************************************************
933 *************************************************/
935 /* Signal handler for handling SIGTERM. Again, try to finish tidily.
937 Argument: signal number (SIGTERM)
942 command_sigterm_handler(int sig)
944 sig = sig; /* Keep picky compilers happy */
945 log_write(0, LOG_MAIN, "%s closed after SIGTERM", smtp_get_connection_info());
946 if (smtp_batched_input)
947 moan_smtp_batch(NULL, "421 SIGTERM received"); /* Does not return */
948 smtp_notquit_exit(US"signal-exit", US"421",
949 US"%s: Service not available - closing connection", smtp_active_hostname);
950 exim_exit(EXIT_FAILURE, US"receiving");
957 /*************************************************
958 * Restore socket timeout to previous value *
959 *************************************************/
960 /* If the previous value was successfully retrieved, restore
961 it before returning control to the non-proxy routines
963 Arguments: fd - File descriptor for input
964 get_ok - Successfully retrieved previous values
965 tvtmp - Time struct with previous values
966 vslen - Length of time struct
970 restore_socket_timeout(int fd, int get_ok, struct timeval * tvtmp, socklen_t vslen)
973 (void) setsockopt(fd, SOL_SOCKET, SO_RCVTIMEO, CS tvtmp, vslen);
976 /*************************************************
977 * Check if host is required proxy host *
978 *************************************************/
979 /* The function determines if inbound host will be a regular smtp host
980 or if it is configured that it must use Proxy Protocol. A local
988 check_proxy_protocol_host()
992 if ( sender_host_address
993 && (rc = verify_check_this_host(CUSS &hosts_proxy, NULL, NULL,
994 sender_host_address, NULL)) == OK)
997 debug_printf("Detected proxy protocol configured host\n");
998 proxy_session = TRUE;
1000 return proxy_session;
1004 /*************************************************
1005 * Read data until newline or end of buffer *
1006 *************************************************/
1007 /* While SMTP is server-speaks-first, TLS is client-speaks-first, so we can't
1008 read an entire buffer and assume there will be nothing past a proxy protocol
1009 header. Our approach normally is to use stdio, but again that relies upon
1010 "STARTTLS\r\n" and a server response before the client starts TLS handshake, or
1011 reading _nothing_ before client TLS handshake. So we don't want to use the
1012 usual buffering reads which may read enough to block TLS starting.
1014 So unfortunately we're down to "read one byte at a time, with a syscall each,
1015 and expect a little overhead", for all proxy-opened connections which are v1,
1016 just to handle the TLS-on-connect case. Since SSL functions wrap the
1017 underlying fd, we can't assume that we can feed them any already-read content.
1019 We need to know where to read to, the max capacity, and we'll read until we
1020 get a CR and one more character. Let the caller scream if it's CR+!LF.
1022 Return the amount read.
1026 swallow_until_crlf(int fd, uschar *base, int already, int capacity)
1028 uschar *to = base + already;
1034 /* For "PROXY UNKNOWN\r\n" we, at time of writing, expect to have read
1035 up through the \r; for the _normal_ case, we haven't yet seen the \r. */
1037 cr = memchr(base, '\r', already);
1040 if ((cr - base) < already - 1)
1042 /* \r and presumed \n already within what we have; probably not
1043 actually proxy protocol, but abort cleanly. */
1046 /* \r is last character read, just need one more. */
1050 while (capacity > 0)
1052 do { ret = recv(fd, to, 1, 0); } while (ret == -1 && errno == EINTR);
1064 /* reached end without having room for a final newline, abort */
1069 /*************************************************
1070 * Setup host for proxy protocol *
1071 *************************************************/
1072 /* The function configures the connection based on a header from the
1073 inbound host to use Proxy Protocol. The specification is very exact
1074 so exit with an error if do not find the exact required pieces. This
1075 includes an incorrect number of spaces separating args.
1078 Returns: Boolean success
1082 setup_proxy_protocol_host()
1094 struct { /* TCP/UDP over IPv4, len = 12 */
1100 struct { /* TCP/UDP over IPv6, len = 36 */
1101 uint8_t src_addr[16];
1102 uint8_t dst_addr[16];
1106 struct { /* AF_UNIX sockets, len = 216 */
1107 uschar src_addr[108];
1108 uschar dst_addr[108];
1114 /* Temp variables used in PPv2 address:port parsing */
1116 char tmpip[INET_ADDRSTRLEN];
1117 struct sockaddr_in tmpaddr;
1118 char tmpip6[INET6_ADDRSTRLEN];
1119 struct sockaddr_in6 tmpaddr6;
1121 /* We can't read "all data until end" because while SMTP is
1122 server-speaks-first, the TLS handshake is client-speaks-first, so for
1123 TLS-on-connect ports the proxy protocol header will usually be immediately
1124 followed by a TLS handshake, and with N TLS libraries, we can't reliably
1125 reinject data for reading by those. So instead we first read "enough to be
1126 safely read within the header, and figure out how much more to read".
1127 For v1 we will later read to the end-of-line, for v2 we will read based upon
1130 The v2 sig is 12 octets, and another 4 gets us the length, so we know how much
1131 data is needed total. For v1, where the line looks like:
1132 PROXY TCPn L3src L3dest SrcPort DestPort \r\n
1134 However, for v1 there's also `PROXY UNKNOWN\r\n` which is only 15 octets.
1135 We seem to support that. So, if we read 14 octets then we can tell if we're
1136 v2 or v1. If we're v1, we can continue reading as normal.
1138 If we're v2, we can't slurp up the entire header. We need the length in the
1139 15th & 16th octets, then to read everything after that.
1141 So to safely handle v1 and v2, with client-sent-first supported correctly,
1142 we have to do a minimum of 3 read calls, not 1. Eww.
1145 #define PROXY_INITIAL_READ 14
1146 #define PROXY_V2_HEADER_SIZE 16
1147 #if PROXY_INITIAL_READ > PROXY_V2_HEADER_SIZE
1148 # error Code bug in sizes of data to read for proxy usage
1153 int fd = fileno(smtp_in);
1154 const char v2sig[12] = "\x0D\x0A\x0D\x0A\x00\x0D\x0A\x51\x55\x49\x54\x0A";
1155 uschar * iptype; /* To display debug info */
1157 struct timeval tvtmp;
1158 socklen_t vslen = sizeof(struct timeval);
1161 /* Save current socket timeout values */
1162 get_ok = getsockopt(fd, SOL_SOCKET, SO_RCVTIMEO, CS &tvtmp, &vslen);
1164 /* Proxy Protocol host must send header within a short time
1165 (default 3 seconds) or it's considered invalid */
1166 tv.tv_sec = PROXY_NEGOTIATION_TIMEOUT_SEC;
1167 tv.tv_usec = PROXY_NEGOTIATION_TIMEOUT_USEC;
1168 if (setsockopt(fd, SOL_SOCKET, SO_RCVTIMEO, CS &tv, sizeof(tv)) < 0)
1173 /* The inbound host was declared to be a Proxy Protocol host, so
1174 don't do a PEEK into the data, actually slurp up enough to be
1175 "safe". Can't take it all because TLS-on-connect clients follow
1176 immediately with TLS handshake. */
1177 ret = recv(fd, &hdr, PROXY_INITIAL_READ, 0);
1179 while (ret == -1 && errno == EINTR);
1184 /* For v2, handle reading the length, and then the rest. */
1185 if ((ret == PROXY_INITIAL_READ) && (memcmp(&hdr.v2, v2sig, sizeof(v2sig)) == 0))
1190 /* First get the length fields. */
1193 retmore = recv(fd, (uschar*)&hdr + ret, PROXY_V2_HEADER_SIZE - PROXY_INITIAL_READ, 0);
1194 } while (retmore == -1 && errno == EINTR);
1199 ver = (hdr.v2.ver_cmd & 0xf0) >> 4;
1201 /* May 2014: haproxy combined the version and command into one byte to
1202 allow two full bytes for the length field in order to proxy SSL
1203 connections. SSL Proxy is not supported in this version of Exim, but
1204 must still separate values here. */
1208 DEBUG(D_receive) debug_printf("Invalid Proxy Protocol version: %d\n", ver);
1212 /* The v2 header will always be 16 bytes per the spec. */
1213 size = 16 + ntohs(hdr.v2.len);
1214 DEBUG(D_receive) debug_printf("Detected PROXYv2 header, size %d (limit %d)\n",
1215 size, (int)sizeof(hdr));
1217 /* We should now have 16 octets (PROXY_V2_HEADER_SIZE), and we know the total
1218 amount that we need. Double-check that the size is not unreasonable, then
1220 if (size > sizeof(hdr))
1222 DEBUG(D_receive) debug_printf("PROXYv2 header size unreasonably large; security attack?\n");
1230 retmore = recv(fd, (uschar*)&hdr + ret, size-ret, 0);
1231 } while (retmore == -1 && errno == EINTR);
1235 DEBUG(D_receive) debug_printf("PROXYv2: have %d/%d required octets\n", ret, size);
1236 } while (ret < size);
1238 } /* end scope for getting rest of data for v2 */
1240 /* At this point: if PROXYv2, we've read the exact size required for all data;
1241 if PROXYv1 then we've read "less than required for any valid line" and should
1244 if (ret >= 16 && memcmp(&hdr.v2, v2sig, 12) == 0)
1246 uint8_t cmd = (hdr.v2.ver_cmd & 0x0f);
1250 case 0x01: /* PROXY command */
1253 case 0x11: /* TCPv4 address type */
1255 tmpaddr.sin_addr.s_addr = hdr.v2.addr.ip4.src_addr;
1256 inet_ntop(AF_INET, &tmpaddr.sin_addr, CS &tmpip, sizeof(tmpip));
1257 if (!string_is_ip_address(US tmpip, NULL))
1259 DEBUG(D_receive) debug_printf("Invalid %s source IP\n", iptype);
1262 proxy_local_address = sender_host_address;
1263 sender_host_address = string_copy(US tmpip);
1264 tmpport = ntohs(hdr.v2.addr.ip4.src_port);
1265 proxy_local_port = sender_host_port;
1266 sender_host_port = tmpport;
1267 /* Save dest ip/port */
1268 tmpaddr.sin_addr.s_addr = hdr.v2.addr.ip4.dst_addr;
1269 inet_ntop(AF_INET, &tmpaddr.sin_addr, CS &tmpip, sizeof(tmpip));
1270 if (!string_is_ip_address(US tmpip, NULL))
1272 DEBUG(D_receive) debug_printf("Invalid %s dest port\n", iptype);
1275 proxy_external_address = string_copy(US tmpip);
1276 tmpport = ntohs(hdr.v2.addr.ip4.dst_port);
1277 proxy_external_port = tmpport;
1279 case 0x21: /* TCPv6 address type */
1281 memmove(tmpaddr6.sin6_addr.s6_addr, hdr.v2.addr.ip6.src_addr, 16);
1282 inet_ntop(AF_INET6, &tmpaddr6.sin6_addr, CS &tmpip6, sizeof(tmpip6));
1283 if (!string_is_ip_address(US tmpip6, NULL))
1285 DEBUG(D_receive) debug_printf("Invalid %s source IP\n", iptype);
1288 proxy_local_address = sender_host_address;
1289 sender_host_address = string_copy(US tmpip6);
1290 tmpport = ntohs(hdr.v2.addr.ip6.src_port);
1291 proxy_local_port = sender_host_port;
1292 sender_host_port = tmpport;
1293 /* Save dest ip/port */
1294 memmove(tmpaddr6.sin6_addr.s6_addr, hdr.v2.addr.ip6.dst_addr, 16);
1295 inet_ntop(AF_INET6, &tmpaddr6.sin6_addr, CS &tmpip6, sizeof(tmpip6));
1296 if (!string_is_ip_address(US tmpip6, NULL))
1298 DEBUG(D_receive) debug_printf("Invalid %s dest port\n", iptype);
1301 proxy_external_address = string_copy(US tmpip6);
1302 tmpport = ntohs(hdr.v2.addr.ip6.dst_port);
1303 proxy_external_port = tmpport;
1307 debug_printf("Unsupported PROXYv2 connection type: 0x%02x\n",
1311 /* Unsupported protocol, keep local connection address */
1313 case 0x00: /* LOCAL command */
1314 /* Keep local connection address for LOCAL */
1319 debug_printf("Unsupported PROXYv2 command: 0x%x\n", cmd);
1323 else if (ret >= 8 && memcmp(hdr.v1.line, "PROXY", 5) == 0)
1327 uschar *sp; /* Utility variables follow */
1332 /* get the rest of the line */
1333 r2 = swallow_until_crlf(fd, (uschar*)&hdr, ret, sizeof(hdr)-ret);
1338 p = string_copy(hdr.v1.line);
1339 end = memchr(p, '\r', ret - 1);
1341 if (!end || (end == (uschar*)&hdr + ret) || end[1] != '\n')
1343 DEBUG(D_receive) debug_printf("Partial or invalid PROXY header\n");
1346 *end = '\0'; /* Terminate the string */
1347 size = end + 2 - p; /* Skip header + CRLF */
1348 DEBUG(D_receive) debug_printf("Detected PROXYv1 header\n");
1349 DEBUG(D_receive) debug_printf("Bytes read not within PROXY header: %d\n", ret - size);
1350 /* Step through the string looking for the required fields. Ensure
1351 strict adherence to required formatting, exit for any error. */
1353 if (!isspace(*(p++)))
1355 DEBUG(D_receive) debug_printf("Missing space after PROXY command\n");
1358 if (!Ustrncmp(p, CCS"TCP4", 4))
1360 else if (!Ustrncmp(p,CCS"TCP6", 4))
1362 else if (!Ustrncmp(p,CCS"UNKNOWN", 7))
1364 iptype = US"Unknown";
1369 DEBUG(D_receive) debug_printf("Invalid TCP type\n");
1373 p += Ustrlen(iptype);
1374 if (!isspace(*(p++)))
1376 DEBUG(D_receive) debug_printf("Missing space after TCP4/6 command\n");
1379 /* Find the end of the arg */
1380 if ((sp = Ustrchr(p, ' ')) == NULL)
1383 debug_printf("Did not find proxied src %s\n", iptype);
1387 if(!string_is_ip_address(p, NULL))
1390 debug_printf("Proxied src arg is not an %s address\n", iptype);
1393 proxy_local_address = sender_host_address;
1394 sender_host_address = p;
1396 if ((sp = Ustrchr(p, ' ')) == NULL)
1399 debug_printf("Did not find proxy dest %s\n", iptype);
1403 if(!string_is_ip_address(p, NULL))
1406 debug_printf("Proxy dest arg is not an %s address\n", iptype);
1409 proxy_external_address = p;
1411 if ((sp = Ustrchr(p, ' ')) == NULL)
1413 DEBUG(D_receive) debug_printf("Did not find proxied src port\n");
1417 tmp_port = strtol(CCS p, &endc, 10);
1418 if (*endc || tmp_port == 0)
1421 debug_printf("Proxied src port '%s' not an integer\n", p);
1424 proxy_local_port = sender_host_port;
1425 sender_host_port = tmp_port;
1427 if ((sp = Ustrchr(p, '\0')) == NULL)
1429 DEBUG(D_receive) debug_printf("Did not find proxy dest port\n");
1432 tmp_port = strtol(CCS p, &endc, 10);
1433 if (*endc || tmp_port == 0)
1436 debug_printf("Proxy dest port '%s' not an integer\n", p);
1439 proxy_external_port = tmp_port;
1440 /* Already checked for /r /n above. Good V1 header received. */
1444 /* Wrong protocol */
1445 DEBUG(D_receive) debug_printf("Invalid proxy protocol version negotiation\n");
1446 (void) swallow_until_crlf(fd, (uschar*)&hdr, ret, sizeof(hdr)-ret);
1452 debug_printf("Valid %s sender from Proxy Protocol header\n", iptype);
1453 yield = proxy_session;
1455 /* Don't flush any potential buffer contents. Any input on proxyfail
1456 should cause a synchronization failure */
1459 restore_socket_timeout(fd, get_ok, &tvtmp, vslen);
1464 sender_host_name = NULL;
1465 (void) host_name_lookup();
1466 host_build_sender_fullhost();
1470 proxy_session_failed = TRUE;
1472 debug_printf("Failure to extract proxied host, only QUIT allowed\n");
1479 /*************************************************
1480 * Read one command line *
1481 *************************************************/
1483 /* Strictly, SMTP commands coming over the net are supposed to end with CRLF.
1484 There are sites that don't do this, and in any case internal SMTP probably
1485 should check only for LF. Consequently, we check here for LF only. The line
1486 ends up with [CR]LF removed from its end. If we get an overlong line, treat as
1487 an unknown command. The command is read into the global smtp_cmd_buffer so that
1488 it is available via $smtp_command.
1490 The character reading routine sets up a timeout for each block actually read
1491 from the input (which may contain more than one command). We set up a special
1492 signal handler that closes down the session on a timeout. Control does not
1493 return when it runs.
1496 check_sync if TRUE, check synchronization rules if global option is TRUE
1497 buffer_lim maximum to buffer in lower layer
1499 Returns: a code identifying the command (enumerated above)
1503 smtp_read_command(BOOL check_sync, unsigned buffer_lim)
1508 BOOL hadnull = FALSE;
1510 os_non_restarting_signal(SIGALRM, command_timeout_handler);
1512 while ((c = (receive_getc)(buffer_lim)) != '\n' && c != EOF)
1514 if (ptr >= SMTP_CMD_BUFFER_SIZE)
1516 os_non_restarting_signal(SIGALRM, sigalrm_handler);
1524 smtp_cmd_buffer[ptr++] = c;
1527 receive_linecount++; /* For BSMTP errors */
1528 os_non_restarting_signal(SIGALRM, sigalrm_handler);
1530 /* If hit end of file, return pseudo EOF command. Whether we have a
1531 part-line already read doesn't matter, since this is an error state. */
1533 if (c == EOF) return EOF_CMD;
1535 /* Remove any CR and white space at the end of the line, and terminate the
1538 while (ptr > 0 && isspace(smtp_cmd_buffer[ptr-1])) ptr--;
1539 smtp_cmd_buffer[ptr] = 0;
1541 DEBUG(D_receive) debug_printf("SMTP<< %s\n", smtp_cmd_buffer);
1543 /* NULLs are not allowed in SMTP commands */
1545 if (hadnull) return BADCHAR_CMD;
1547 /* Scan command list and return identity, having set the data pointer
1548 to the start of the actual data characters. Check for SMTP synchronization
1551 for (p = cmd_list; p < cmd_list_end; p++)
1553 #ifdef SUPPORT_PROXY
1554 /* Only allow QUIT command if Proxy Protocol parsing failed */
1555 if (proxy_session && proxy_session_failed && p->cmd != QUIT_CMD)
1559 && strncmpic(smtp_cmd_buffer, US p->name, p->len) == 0
1560 && ( smtp_cmd_buffer[p->len-1] == ':' /* "mail from:" or "rcpt to:" */
1561 || smtp_cmd_buffer[p->len] == 0
1562 || smtp_cmd_buffer[p->len] == ' '
1565 if (smtp_inptr < smtp_inend && /* Outstanding input */
1566 p->cmd < sync_cmd_limit && /* Command should sync */
1567 check_sync && /* Local flag set */
1568 smtp_enforce_sync && /* Global flag set */
1569 sender_host_address != NULL && /* Not local input */
1570 !sender_host_notsocket) /* Really is a socket */
1573 /* The variables $smtp_command and $smtp_command_argument point into the
1574 unmodified input buffer. A copy of the latter is taken for actual
1575 processing, so that it can be chopped up into separate parts if necessary,
1576 for example, when processing a MAIL command options such as SIZE that can
1577 follow the sender address. */
1579 smtp_cmd_argument = smtp_cmd_buffer + p->len;
1580 while (isspace(*smtp_cmd_argument)) smtp_cmd_argument++;
1581 Ustrcpy(smtp_data_buffer, smtp_cmd_argument);
1582 smtp_cmd_data = smtp_data_buffer;
1584 /* Count non-mail commands from those hosts that are controlled in this
1585 way. The default is all hosts. We don't waste effort checking the list
1586 until we get a non-mail command, but then cache the result to save checking
1587 again. If there's a DEFER while checking the host, assume it's in the list.
1589 Note that one instance of RSET, EHLO/HELO, and STARTTLS is allowed at the
1590 start of each incoming message by fiddling with the value in the table. */
1592 if (!p->is_mail_cmd)
1594 if (count_nonmail == TRUE_UNSET) count_nonmail =
1595 verify_check_host(&smtp_accept_max_nonmail_hosts) != FAIL;
1596 if (count_nonmail && ++nonmail_command_count > smtp_accept_max_nonmail)
1597 return TOO_MANY_NONMAIL_CMD;
1600 /* If there is data for a command that does not expect it, generate the
1603 return (p->has_arg || *smtp_cmd_data == 0)? p->cmd : BADARG_CMD;
1607 #ifdef SUPPORT_PROXY
1608 /* Only allow QUIT command if Proxy Protocol parsing failed */
1609 if (proxy_session && proxy_session_failed)
1610 return PROXY_FAIL_IGNORE_CMD;
1613 /* Enforce synchronization for unknown commands */
1615 if ( smtp_inptr < smtp_inend /* Outstanding input */
1616 && check_sync /* Local flag set */
1617 && smtp_enforce_sync /* Global flag set */
1618 && sender_host_address /* Not local input */
1619 && !sender_host_notsocket) /* Really is a socket */
1627 /*************************************************
1628 * Forced closedown of call *
1629 *************************************************/
1631 /* This function is called from log.c when Exim is dying because of a serious
1632 disaster, and also from some other places. If an incoming non-batched SMTP
1633 channel is open, it swallows the rest of the incoming message if in the DATA
1634 phase, sends the reply string, and gives an error to all subsequent commands
1635 except QUIT. The existence of an SMTP call is detected by the non-NULLness of
1639 message SMTP reply string to send, excluding the code
1645 smtp_closedown(uschar *message)
1647 if (!smtp_in || smtp_batched_input) return;
1648 receive_swallow_smtp();
1649 smtp_printf("421 %s\r\n", FALSE, message);
1651 for (;;) switch(smtp_read_command(FALSE, GETC_BUFFER_UNLIMITED))
1657 smtp_printf("221 %s closing connection\r\n", FALSE, smtp_active_hostname);
1662 smtp_printf("250 Reset OK\r\n", FALSE);
1666 smtp_printf("421 %s\r\n", FALSE, message);
1674 /*************************************************
1675 * Set up connection info for logging *
1676 *************************************************/
1678 /* This function is called when logging information about an SMTP connection.
1679 It sets up appropriate source information, depending on the type of connection.
1680 If sender_fullhost is NULL, we are at a very early stage of the connection;
1681 just use the IP address.
1684 Returns: a string describing the connection
1688 smtp_get_connection_info(void)
1690 const uschar * hostname = sender_fullhost
1691 ? sender_fullhost : sender_host_address;
1694 return string_sprintf("SMTP connection from %s", hostname);
1696 if (sender_host_unknown || sender_host_notsocket)
1697 return string_sprintf("SMTP connection from %s", sender_ident);
1700 return string_sprintf("SMTP connection from %s (via inetd)", hostname);
1702 if (LOGGING(incoming_interface) && interface_address != NULL)
1703 return string_sprintf("SMTP connection from %s I=[%s]:%d", hostname,
1704 interface_address, interface_port);
1706 return string_sprintf("SMTP connection from %s", hostname);
1712 /* Append TLS-related information to a log line
1715 g String under construction: allocated string to extend, or NULL
1717 Returns: Allocated string or NULL
1720 s_tlslog(gstring * g)
1722 if (LOGGING(tls_cipher) && tls_in.cipher)
1723 g = string_append(g, 2, US" X=", tls_in.cipher);
1724 if (LOGGING(tls_certificate_verified) && tls_in.cipher)
1725 g = string_append(g, 2, US" CV=", tls_in.certificate_verified? "yes":"no");
1726 if (LOGGING(tls_peerdn) && tls_in.peerdn)
1727 g = string_append(g, 3, US" DN=\"", string_printing(tls_in.peerdn), US"\"");
1728 if (LOGGING(tls_sni) && tls_in.sni)
1729 g = string_append(g, 3, US" SNI=\"", string_printing(tls_in.sni), US"\"");
1734 /*************************************************
1735 * Log lack of MAIL if so configured *
1736 *************************************************/
1738 /* This function is called when an SMTP session ends. If the log selector
1739 smtp_no_mail is set, write a log line giving some details of what has happened
1740 in the SMTP session.
1747 smtp_log_no_mail(void)
1753 if (smtp_mailcmd_count > 0 || !LOGGING(smtp_no_mail))
1756 if (sender_host_authenticated)
1758 g = string_append(g, 2, US" A=", sender_host_authenticated);
1759 if (authenticated_id) g = string_append(g, 2, US":", authenticated_id);
1766 sep = smtp_connection_had[SMTP_HBUFF_SIZE-1] != SCH_NONE ? US" C=..." : US" C=";
1768 for (i = smtp_ch_index; i < SMTP_HBUFF_SIZE; i++)
1769 if (smtp_connection_had[i] != SCH_NONE)
1771 g = string_append(g, 2, sep, smtp_names[smtp_connection_had[i]]);
1775 for (i = 0; i < smtp_ch_index; i++)
1777 g = string_append(g, 2, sep, smtp_names[smtp_connection_had[i]]);
1781 if (!(s = string_from_gstring(g))) s = US"";
1783 log_write(0, LOG_MAIN, "no MAIL in %sSMTP connection from %s D=%s%s",
1784 tcp_in_fastopen ? US"TFO " : US"",
1785 host_and_ident(FALSE), string_timesince(&smtp_connection_start), s);
1789 /* Return list of recent smtp commands */
1795 gstring * list = NULL;
1798 for (i = smtp_ch_index; i < SMTP_HBUFF_SIZE; i++)
1799 if (smtp_connection_had[i] != SCH_NONE)
1800 list = string_append_listele(list, ',', smtp_names[smtp_connection_had[i]]);
1802 for (i = 0; i < smtp_ch_index; i++)
1803 list = string_append_listele(list, ',', smtp_names[smtp_connection_had[i]]);
1805 s = string_from_gstring(list);
1806 return s ? s : US"";
1812 /*************************************************
1813 * Check HELO line and set sender_helo_name *
1814 *************************************************/
1816 /* Check the format of a HELO line. The data for HELO/EHLO is supposed to be
1817 the domain name of the sending host, or an ip literal in square brackets. The
1818 argument is placed in sender_helo_name, which is in malloc store, because it
1819 must persist over multiple incoming messages. If helo_accept_junk is set, this
1820 host is permitted to send any old junk (needed for some broken hosts).
1821 Otherwise, helo_allow_chars can be used for rogue characters in general
1822 (typically people want to let in underscores).
1825 s the data portion of the line (already past any white space)
1827 Returns: TRUE or FALSE
1831 check_helo(uschar *s)
1834 uschar *end = s + Ustrlen(s);
1835 BOOL yield = helo_accept_junk;
1837 /* Discard any previous helo name */
1839 if (sender_helo_name)
1841 store_free(sender_helo_name);
1842 sender_helo_name = NULL;
1845 /* Skip tests if junk is permitted. */
1849 /* Allow the new standard form for IPv6 address literals, namely,
1850 [IPv6:....], and because someone is bound to use it, allow an equivalent
1851 IPv4 form. Allow plain addresses as well. */
1858 if (strncmpic(s, US"[IPv6:", 6) == 0)
1859 yield = (string_is_ip_address(s+6, NULL) == 6);
1860 else if (strncmpic(s, US"[IPv4:", 6) == 0)
1861 yield = (string_is_ip_address(s+6, NULL) == 4);
1863 yield = (string_is_ip_address(s+1, NULL) != 0);
1868 /* Non-literals must be alpha, dot, hyphen, plus any non-valid chars
1869 that have been configured (usually underscore - sigh). */
1872 for (yield = TRUE; *s; s++)
1873 if (!isalnum(*s) && *s != '.' && *s != '-' &&
1874 Ustrchr(helo_allow_chars, *s) == NULL)
1880 /* Save argument if OK */
1882 if (yield) sender_helo_name = string_copy_malloc(start);
1890 /*************************************************
1891 * Extract SMTP command option *
1892 *************************************************/
1894 /* This function picks the next option setting off the end of smtp_cmd_data. It
1895 is called for MAIL FROM and RCPT TO commands, to pick off the optional ESMTP
1896 things that can appear there.
1899 name point this at the name
1900 value point this at the data string
1902 Returns: TRUE if found an option
1906 extract_option(uschar **name, uschar **value)
1909 uschar *v = smtp_cmd_data + Ustrlen(smtp_cmd_data) - 1;
1910 while (isspace(*v)) v--;
1912 while (v > smtp_cmd_data && *v != '=' && !isspace(*v))
1914 /* Take care to not stop at a space embedded in a quoted local-part */
1916 if (*v == '"') do v--; while (*v != '"' && v > smtp_cmd_data+1);
1923 while(isalpha(n[-1])) n--;
1924 /* RFC says SP, but TAB seen in wild and other major MTAs accept it */
1925 if (!isspace(n[-1])) return FALSE;
1931 if (v == smtp_cmd_data) return FALSE;
1943 /*************************************************
1944 * Reset for new message *
1945 *************************************************/
1947 /* This function is called whenever the SMTP session is reset from
1948 within either of the setup functions; also from the daemon loop.
1950 Argument: the stacking pool storage reset point
1955 smtp_reset(void *reset_point)
1957 recipients_list = NULL;
1958 rcpt_count = rcpt_defer_count = rcpt_fail_count =
1959 raw_recipients_count = recipients_count = recipients_list_max = 0;
1960 message_linecount = 0;
1962 acl_added_headers = NULL;
1963 acl_removed_headers = NULL;
1964 queue_only_policy = FALSE;
1965 rcpt_smtp_response = NULL;
1966 rcpt_smtp_response_same = TRUE;
1967 rcpt_in_progress = FALSE;
1968 deliver_freeze = FALSE; /* Can be set by ACL */
1969 freeze_tell = freeze_tell_config; /* Can be set by ACL */
1970 fake_response = OK; /* Can be set by ACL */
1971 #ifdef WITH_CONTENT_SCAN
1972 no_mbox_unspool = FALSE; /* Can be set by ACL */
1974 submission_mode = FALSE; /* Can be set by ACL */
1975 suppress_local_fixups = suppress_local_fixups_default; /* Can be set by ACL */
1976 active_local_from_check = local_from_check; /* Can be set by ACL */
1977 active_local_sender_retain = local_sender_retain; /* Can be set by ACL */
1978 sending_ip_address = NULL;
1979 return_path = sender_address = NULL;
1980 sender_data = NULL; /* Can be set by ACL */
1981 deliver_localpart_parent = deliver_localpart_orig = NULL;
1982 deliver_domain_parent = deliver_domain_orig = NULL;
1983 callout_address = NULL;
1984 submission_name = NULL; /* Can be set by ACL */
1985 raw_sender = NULL; /* After SMTP rewrite, before qualifying */
1986 sender_address_unrewritten = NULL; /* Set only after verify rewrite */
1987 sender_verified_list = NULL; /* No senders verified */
1988 memset(sender_address_cache, 0, sizeof(sender_address_cache));
1989 memset(sender_domain_cache, 0, sizeof(sender_domain_cache));
1991 authenticated_sender = NULL;
1992 #ifdef EXPERIMENTAL_BRIGHTMAIL
1994 bmi_verdicts = NULL;
1996 dnslist_domain = dnslist_matched = NULL;
1997 #ifndef DISABLE_DKIM
1998 dkim_cur_signer = dkim_signers = NULL;
1999 dkim_disable_verify = dkim_collect_input = FALSE;
2003 deliver_host = deliver_host_address = NULL; /* Can be set by ACL */
2004 #ifndef DISABLE_PRDR
2005 prdr_requested = FALSE;
2008 spf_header_comment = spf_received = spf_result = spf_smtp_comment = NULL;
2009 spf_result_guessed = FALSE;
2011 #ifdef EXPERIMENTAL_DMARC
2012 dmarc_has_been_checked = dmarc_disable_verify = dmarc_enable_forensic = FALSE;
2013 dmarc_domain_policy = dmarc_forensic_sender =
2014 dmarc_history_file = dmarc_status = dmarc_status_text =
2015 dmarc_used_domain = NULL;
2017 #ifdef EXPERIMENTAL_ARC
2018 arc_state = arc_state_reason = NULL;
2021 message_smtputf8 = FALSE;
2023 body_linecount = body_zerocount = 0;
2025 sender_rate = sender_rate_limit = sender_rate_period = NULL;
2026 ratelimiters_mail = NULL; /* Updated by ratelimit ACL condition */
2027 /* Note that ratelimiters_conn persists across resets. */
2029 /* Reset message ACL variables */
2033 /* The message body variables use malloc store. They may be set if this is
2034 not the first message in an SMTP session and the previous message caused them
2035 to be referenced in an ACL. */
2039 store_free(message_body);
2040 message_body = NULL;
2043 if (message_body_end)
2045 store_free(message_body_end);
2046 message_body_end = NULL;
2049 /* Warning log messages are also saved in malloc store. They are saved to avoid
2050 repetition in the same message, but it seems right to repeat them for different
2053 while (acl_warn_logged)
2055 string_item *this = acl_warn_logged;
2056 acl_warn_logged = acl_warn_logged->next;
2059 store_reset(reset_point);
2066 /*************************************************
2067 * Initialize for incoming batched SMTP message *
2068 *************************************************/
2070 /* This function is called from smtp_setup_msg() in the case when
2071 smtp_batched_input is true. This happens when -bS is used to pass a whole batch
2072 of messages in one file with SMTP commands between them. All errors must be
2073 reported by sending a message, and only MAIL FROM, RCPT TO, and DATA are
2074 relevant. After an error on a sender, or an invalid recipient, the remainder
2075 of the message is skipped. The value of received_protocol is already set.
2078 Returns: > 0 message successfully started (reached DATA)
2079 = 0 QUIT read or end of file reached
2080 < 0 should not occur
2084 smtp_setup_batch_msg(void)
2087 void *reset_point = store_get(0);
2089 /* Save the line count at the start of each transaction - single commands
2090 like HELO and RSET count as whole transactions. */
2092 bsmtp_transaction_linecount = receive_linecount;
2094 if ((receive_feof)()) return 0; /* Treat EOF as QUIT */
2096 cancel_cutthrough_connection(TRUE, US"smtp_setup_batch_msg");
2097 smtp_reset(reset_point); /* Reset for start of message */
2099 /* Deal with SMTP commands. This loop is exited by setting done to a POSITIVE
2100 value. The values are 2 larger than the required yield of the function. */
2105 uschar *recipient = NULL;
2106 int start, end, sender_domain, recipient_domain;
2108 switch(smtp_read_command(FALSE, GETC_BUFFER_UNLIMITED))
2110 /* The HELO/EHLO commands set sender_address_helo if they have
2111 valid data; otherwise they are ignored, except that they do
2112 a reset of the state. */
2117 check_helo(smtp_cmd_data);
2121 cancel_cutthrough_connection(TRUE, US"RSET received");
2122 smtp_reset(reset_point);
2123 bsmtp_transaction_linecount = receive_linecount;
2127 /* The MAIL FROM command requires an address as an operand. All we
2128 do here is to parse it for syntactic correctness. The form "<>" is
2129 a special case which converts into an empty string. The start/end
2130 pointers in the original are not used further for this address, as
2131 it is the canonical extracted address which is all that is kept. */
2134 smtp_mailcmd_count++; /* Count for no-mail log */
2135 if (sender_address != NULL)
2136 /* The function moan_smtp_batch() does not return. */
2137 moan_smtp_batch(smtp_cmd_buffer, "503 Sender already given");
2139 if (smtp_cmd_data[0] == 0)
2140 /* The function moan_smtp_batch() does not return. */
2141 moan_smtp_batch(smtp_cmd_buffer, "501 MAIL FROM must have an address operand");
2143 /* Reset to start of message */
2145 cancel_cutthrough_connection(TRUE, US"MAIL received");
2146 smtp_reset(reset_point);
2148 /* Apply SMTP rewrite */
2150 raw_sender = ((rewrite_existflags & rewrite_smtp) != 0)?
2151 rewrite_one(smtp_cmd_data, rewrite_smtp|rewrite_smtp_sender, NULL, FALSE,
2152 US"", global_rewrite_rules) : smtp_cmd_data;
2154 /* Extract the address; the TRUE flag allows <> as valid */
2157 parse_extract_address(raw_sender, &errmess, &start, &end, &sender_domain,
2161 /* The function moan_smtp_batch() does not return. */
2162 moan_smtp_batch(smtp_cmd_buffer, "501 %s", errmess);
2164 sender_address = string_copy(raw_sender);
2166 /* Qualify unqualified sender addresses if permitted to do so. */
2169 && sender_address[0] != 0 && sender_address[0] != '@')
2170 if (allow_unqualified_sender)
2172 sender_address = rewrite_address_qualify(sender_address, FALSE);
2173 DEBUG(D_receive) debug_printf("unqualified address %s accepted "
2174 "and rewritten\n", raw_sender);
2176 /* The function moan_smtp_batch() does not return. */
2178 moan_smtp_batch(smtp_cmd_buffer, "501 sender address must contain "
2183 /* The RCPT TO command requires an address as an operand. All we do
2184 here is to parse it for syntactic correctness. There may be any number
2185 of RCPT TO commands, specifying multiple senders. We build them all into
2186 a data structure that is in argc/argv format. The start/end values
2187 given by parse_extract_address are not used, as we keep only the
2188 extracted address. */
2191 if (!sender_address)
2192 /* The function moan_smtp_batch() does not return. */
2193 moan_smtp_batch(smtp_cmd_buffer, "503 No sender yet given");
2195 if (smtp_cmd_data[0] == 0)
2196 /* The function moan_smtp_batch() does not return. */
2197 moan_smtp_batch(smtp_cmd_buffer,
2198 "501 RCPT TO must have an address operand");
2200 /* Check maximum number allowed */
2202 if (recipients_max > 0 && recipients_count + 1 > recipients_max)
2203 /* The function moan_smtp_batch() does not return. */
2204 moan_smtp_batch(smtp_cmd_buffer, "%s too many recipients",
2205 recipients_max_reject? "552": "452");
2207 /* Apply SMTP rewrite, then extract address. Don't allow "<>" as a
2208 recipient address */
2210 recipient = rewrite_existflags & rewrite_smtp
2211 ? rewrite_one(smtp_cmd_data, rewrite_smtp, NULL, FALSE, US"",
2212 global_rewrite_rules)
2215 recipient = parse_extract_address(recipient, &errmess, &start, &end,
2216 &recipient_domain, FALSE);
2219 /* The function moan_smtp_batch() does not return. */
2220 moan_smtp_batch(smtp_cmd_buffer, "501 %s", errmess);
2222 /* If the recipient address is unqualified, qualify it if permitted. Then
2223 add it to the list of recipients. */
2225 if (!recipient_domain)
2226 if (allow_unqualified_recipient)
2228 DEBUG(D_receive) debug_printf("unqualified address %s accepted\n",
2230 recipient = rewrite_address_qualify(recipient, TRUE);
2232 /* The function moan_smtp_batch() does not return. */
2234 moan_smtp_batch(smtp_cmd_buffer,
2235 "501 recipient address must contain a domain");
2237 receive_add_recipient(recipient, -1);
2241 /* The DATA command is legal only if it follows successful MAIL FROM
2242 and RCPT TO commands. This function is complete when a valid DATA
2243 command is encountered. */
2246 if (!sender_address || recipients_count <= 0)
2247 /* The function moan_smtp_batch() does not return. */
2248 if (!sender_address)
2249 moan_smtp_batch(smtp_cmd_buffer,
2250 "503 MAIL FROM:<sender> command must precede DATA");
2252 moan_smtp_batch(smtp_cmd_buffer,
2253 "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)
2383 sender_host_auth_pubname = sender_host_authenticated = NULL;
2384 authenticated_by = NULL;
2387 tls_in.cipher = tls_in.peerdn = NULL;
2388 tls_in.ourcert = tls_in.peercert = NULL;
2390 tls_in.ocsp = OCSP_NOT_REQ;
2391 tls_advertised = FALSE;
2393 dsn_advertised = FALSE;
2395 smtputf8_advertised = FALSE;
2398 /* Reset ACL connection variables */
2402 /* Allow for trailing 0 in the command and data buffers. */
2404 if (!(smtp_cmd_buffer = US malloc(2*SMTP_CMD_BUFFER_SIZE + 2)))
2405 log_write(0, LOG_MAIN|LOG_PANIC_DIE,
2406 "malloc() failed for SMTP command buffer");
2408 smtp_cmd_buffer[0] = 0;
2409 smtp_data_buffer = smtp_cmd_buffer + SMTP_CMD_BUFFER_SIZE + 1;
2411 /* For batched input, the protocol setting can be overridden from the
2412 command line by a trusted caller. */
2414 if (smtp_batched_input)
2416 if (!received_protocol) received_protocol = US"local-bsmtp";
2419 /* For non-batched SMTP input, the protocol setting is forced here. It will be
2420 reset later if any of EHLO/AUTH/STARTTLS are received. */
2424 (sender_host_address ? protocols : protocols_local) [pnormal];
2426 /* Set up the buffer for inputting using direct read() calls, and arrange to
2427 call the local functions instead of the standard C ones. Place a NUL at the
2428 end of the buffer to safety-stop C-string reads from it. */
2430 if (!(smtp_inbuffer = US malloc(IN_BUFFER_SIZE)))
2431 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "malloc() failed for SMTP input buffer");
2432 smtp_inbuffer[IN_BUFFER_SIZE-1] = '\0';
2434 receive_getc = smtp_getc;
2435 receive_getbuf = smtp_getbuf;
2436 receive_get_cache = smtp_get_cache;
2437 receive_ungetc = smtp_ungetc;
2438 receive_feof = smtp_feof;
2439 receive_ferror = smtp_ferror;
2440 receive_smtp_buffered = smtp_buffered;
2441 smtp_inptr = smtp_inend = smtp_inbuffer;
2442 smtp_had_eof = smtp_had_error = 0;
2444 /* Set up the message size limit; this may be host-specific */
2446 thismessage_size_limit = expand_string_integer(message_size_limit, TRUE);
2447 if (expand_string_message)
2449 if (thismessage_size_limit == -1)
2450 log_write(0, LOG_MAIN|LOG_PANIC, "unable to expand message_size_limit: "
2451 "%s", expand_string_message);
2453 log_write(0, LOG_MAIN|LOG_PANIC, "invalid message_size_limit: "
2454 "%s", expand_string_message);
2455 smtp_closedown(US"Temporary local problem - please try later");
2459 /* When a message is input locally via the -bs or -bS options, sender_host_
2460 unknown is set unless -oMa was used to force an IP address, in which case it
2461 is checked like a real remote connection. When -bs is used from inetd, this
2462 flag is not set, causing the sending host to be checked. The code that deals
2463 with IP source routing (if configured) is never required for -bs or -bS and
2464 the flag sender_host_notsocket is used to suppress it.
2466 If smtp_accept_max and smtp_accept_reserve are set, keep some connections in
2467 reserve for certain hosts and/or networks. */
2469 if (!sender_host_unknown)
2472 BOOL reserved_host = FALSE;
2474 /* Look up IP options (source routing info) on the socket if this is not an
2475 -oMa "host", and if any are found, log them and drop the connection.
2477 Linux (and others now, see below) is different to everyone else, so there
2478 has to be some conditional compilation here. Versions of Linux before 2.1.15
2479 used a structure whose name was "options". Somebody finally realized that
2480 this name was silly, and it got changed to "ip_options". I use the
2481 newer name here, but there is a fudge in the script that sets up os.h
2482 to define a macro in older Linux systems.
2484 Sigh. Linux is a fast-moving target. Another generation of Linux uses
2485 glibc 2, which has chosen ip_opts for the structure name. This is now
2486 really a glibc thing rather than a Linux thing, so the condition name
2487 has been changed to reflect this. It is relevant also to GNU/Hurd.
2489 Mac OS 10.x (Darwin) is like the later glibc versions, but without the
2490 setting of the __GLIBC__ macro, so we can't detect it automatically. There's
2491 a special macro defined in the os.h file.
2493 Some DGUX versions on older hardware appear not to support IP options at
2494 all, so there is now a general macro which can be set to cut out this
2497 How to do this properly in IPv6 is not yet known. */
2499 #if !HAVE_IPV6 && !defined(NO_IP_OPTIONS)
2501 #ifdef GLIBC_IP_OPTIONS
2502 #if (!defined __GLIBC__) || (__GLIBC__ < 2)
2507 #elif defined DARWIN_IP_OPTIONS
2513 if (!host_checking && !sender_host_notsocket)
2516 EXIM_SOCKLEN_T optlen = sizeof(struct ip_options) + MAX_IPOPTLEN;
2517 struct ip_options *ipopt = store_get(optlen);
2519 struct ip_opts ipoptblock;
2520 struct ip_opts *ipopt = &ipoptblock;
2521 EXIM_SOCKLEN_T optlen = sizeof(ipoptblock);
2523 struct ipoption ipoptblock;
2524 struct ipoption *ipopt = &ipoptblock;
2525 EXIM_SOCKLEN_T optlen = sizeof(ipoptblock);
2528 /* Occasional genuine failures of getsockopt() have been seen - for
2529 example, "reset by peer". Therefore, just log and give up on this
2530 call, unless the error is ENOPROTOOPT. This error is given by systems
2531 that have the interfaces but not the mechanism - e.g. GNU/Hurd at the time
2532 of writing. So for that error, carry on - we just can't do an IP options
2535 DEBUG(D_receive) debug_printf("checking for IP options\n");
2537 if (getsockopt(fileno(smtp_out), IPPROTO_IP, IP_OPTIONS, US (ipopt),
2540 if (errno != ENOPROTOOPT)
2542 log_write(0, LOG_MAIN, "getsockopt() failed from %s: %s",
2543 host_and_ident(FALSE), strerror(errno));
2544 smtp_printf("451 SMTP service not available\r\n", FALSE);
2549 /* Deal with any IP options that are set. On the systems I have looked at,
2550 the value of MAX_IPOPTLEN has been 40, meaning that there should never be
2551 more logging data than will fit in big_buffer. Nevertheless, after somebody
2552 questioned this code, I've added in some paranoid checking. */
2554 else if (optlen > 0)
2556 uschar *p = big_buffer;
2557 uschar *pend = big_buffer + big_buffer_size;
2558 uschar *opt, *adptr;
2560 struct in_addr addr;
2563 uschar *optstart = US (ipopt->__data);
2565 uschar *optstart = US (ipopt->ip_opts);
2567 uschar *optstart = US (ipopt->ipopt_list);
2570 DEBUG(D_receive) debug_printf("IP options exist\n");
2572 Ustrcpy(p, "IP options on incoming call:");
2575 for (opt = optstart; opt != NULL &&
2576 opt < US (ipopt) + optlen;)
2590 if (!string_format(p, pend-p, " %s [@%s",
2591 (*opt == IPOPT_SSRR)? "SSRR" : "LSRR",
2593 inet_ntoa(*((struct in_addr *)(&(ipopt->faddr))))))
2595 inet_ntoa(ipopt->ip_dst)))
2597 inet_ntoa(ipopt->ipopt_dst)))
2605 optcount = (opt[1] - 3) / sizeof(struct in_addr);
2607 while (optcount-- > 0)
2609 memcpy(&addr, adptr, sizeof(addr));
2610 if (!string_format(p, pend - p - 1, "%s%s",
2611 (optcount == 0)? ":" : "@", inet_ntoa(addr)))
2617 adptr += sizeof(struct in_addr);
2626 if (pend - p < 4 + 3*opt[1]) { opt = NULL; break; }
2629 for (i = 0; i < opt[1]; i++)
2630 p += sprintf(CS p, "%2.2x ", opt[i]);
2639 log_write(0, LOG_MAIN, "%s", big_buffer);
2641 /* Refuse any call with IP options. This is what tcpwrappers 7.5 does. */
2643 log_write(0, LOG_MAIN|LOG_REJECT,
2644 "connection from %s refused (IP options)", host_and_ident(FALSE));
2646 smtp_printf("554 SMTP service not available\r\n", FALSE);
2650 /* Length of options = 0 => there are no options */
2652 else DEBUG(D_receive) debug_printf("no IP options found\n");
2654 #endif /* HAVE_IPV6 && !defined(NO_IP_OPTIONS) */
2656 /* Set keep-alive in socket options. The option is on by default. This
2657 setting is an attempt to get rid of some hanging connections that stick in
2658 read() when the remote end (usually a dialup) goes away. */
2660 if (smtp_accept_keepalive && !sender_host_notsocket)
2661 ip_keepalive(fileno(smtp_out), sender_host_address, FALSE);
2663 /* If the current host matches host_lookup, set the name by doing a
2664 reverse lookup. On failure, sender_host_name will be NULL and
2665 host_lookup_failed will be TRUE. This may or may not be serious - optional
2668 if (verify_check_host(&host_lookup) == OK)
2670 (void)host_name_lookup();
2671 host_build_sender_fullhost();
2674 /* Delay this until we have the full name, if it is looked up. */
2676 set_process_info("handling incoming connection from %s",
2677 host_and_ident(FALSE));
2679 /* Expand smtp_receive_timeout, if needed */
2681 if (smtp_receive_timeout_s)
2684 if ( !(exp = expand_string(smtp_receive_timeout_s))
2686 || (smtp_receive_timeout = readconf_readtime(exp, 0, FALSE)) < 0
2688 log_write(0, LOG_MAIN|LOG_PANIC,
2689 "bad value for smtp_receive_timeout: '%s'", exp ? exp : US"");
2692 /* Test for explicit connection rejection */
2694 if (verify_check_host(&host_reject_connection) == OK)
2696 log_write(L_connection_reject, LOG_MAIN|LOG_REJECT, "refused connection "
2697 "from %s (host_reject_connection)", host_and_ident(FALSE));
2698 smtp_printf("554 SMTP service not available\r\n", FALSE);
2702 /* Test with TCP Wrappers if so configured. There is a problem in that
2703 hosts_ctl() returns 0 (deny) under a number of system failure circumstances,
2704 such as disks dying. In these cases, it is desirable to reject with a 4xx
2705 error instead of a 5xx error. There isn't a "right" way to detect such
2706 problems. The following kludge is used: errno is zeroed before calling
2707 hosts_ctl(). If the result is "reject", a 5xx error is given only if the
2708 value of errno is 0 or ENOENT (which happens if /etc/hosts.{allow,deny} does
2711 #ifdef USE_TCP_WRAPPERS
2713 if (!(tcp_wrappers_name = expand_string(tcp_wrappers_daemon_name)))
2714 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "Expansion of \"%s\" "
2715 "(tcp_wrappers_name) failed: %s", string_printing(tcp_wrappers_name),
2716 expand_string_message);
2718 if (!hosts_ctl(tcp_wrappers_name,
2719 sender_host_name ? CS sender_host_name : STRING_UNKNOWN,
2720 sender_host_address ? CS sender_host_address : STRING_UNKNOWN,
2721 sender_ident ? CS sender_ident : STRING_UNKNOWN))
2723 if (errno == 0 || errno == ENOENT)
2725 HDEBUG(D_receive) debug_printf("tcp wrappers rejection\n");
2726 log_write(L_connection_reject,
2727 LOG_MAIN|LOG_REJECT, "refused connection from %s "
2728 "(tcp wrappers)", host_and_ident(FALSE));
2729 smtp_printf("554 SMTP service not available\r\n", FALSE);
2733 int save_errno = errno;
2734 HDEBUG(D_receive) debug_printf("tcp wrappers rejected with unexpected "
2735 "errno value %d\n", save_errno);
2736 log_write(L_connection_reject,
2737 LOG_MAIN|LOG_REJECT, "temporarily refused connection from %s "
2738 "(tcp wrappers errno=%d)", host_and_ident(FALSE), save_errno);
2739 smtp_printf("451 Temporary local problem - please try later\r\n", FALSE);
2745 /* Check for reserved slots. The value of smtp_accept_count has already been
2746 incremented to include this process. */
2748 if (smtp_accept_max > 0 &&
2749 smtp_accept_count > smtp_accept_max - smtp_accept_reserve)
2751 if ((rc = verify_check_host(&smtp_reserve_hosts)) != OK)
2753 log_write(L_connection_reject,
2754 LOG_MAIN, "temporarily refused connection from %s: not in "
2755 "reserve list: connected=%d max=%d reserve=%d%s",
2756 host_and_ident(FALSE), smtp_accept_count - 1, smtp_accept_max,
2757 smtp_accept_reserve, (rc == DEFER)? " (lookup deferred)" : "");
2758 smtp_printf("421 %s: Too many concurrent SMTP connections; "
2759 "please try again later\r\n", FALSE, smtp_active_hostname);
2762 reserved_host = TRUE;
2765 /* If a load level above which only messages from reserved hosts are
2766 accepted is set, check the load. For incoming calls via the daemon, the
2767 check is done in the superior process if there are no reserved hosts, to
2768 save a fork. In all cases, the load average will already be available
2769 in a global variable at this point. */
2771 if (smtp_load_reserve >= 0 &&
2772 load_average > smtp_load_reserve &&
2774 verify_check_host(&smtp_reserve_hosts) != OK)
2776 log_write(L_connection_reject,
2777 LOG_MAIN, "temporarily refused connection from %s: not in "
2778 "reserve list and load average = %.2f", host_and_ident(FALSE),
2779 (double)load_average/1000.0);
2780 smtp_printf("421 %s: Too much load; please try again later\r\n", FALSE,
2781 smtp_active_hostname);
2785 /* Determine whether unqualified senders or recipients are permitted
2786 for this host. Unfortunately, we have to do this every time, in order to
2787 set the flags so that they can be inspected when considering qualifying
2788 addresses in the headers. For a site that permits no qualification, this
2789 won't take long, however. */
2791 allow_unqualified_sender =
2792 verify_check_host(&sender_unqualified_hosts) == OK;
2794 allow_unqualified_recipient =
2795 verify_check_host(&recipient_unqualified_hosts) == OK;
2797 /* Determine whether HELO/EHLO is required for this host. The requirement
2798 can be hard or soft. */
2800 helo_required = verify_check_host(&helo_verify_hosts) == OK;
2802 helo_verify = verify_check_host(&helo_try_verify_hosts) == OK;
2804 /* Determine whether this hosts is permitted to send syntactic junk
2805 after a HELO or EHLO command. */
2807 helo_accept_junk = verify_check_host(&helo_accept_junk_hosts) == OK;
2810 /* For batch SMTP input we are now done. */
2812 if (smtp_batched_input) return TRUE;
2814 /* If valid Proxy Protocol source is connecting, set up session.
2815 * Failure will not allow any SMTP function other than QUIT. */
2817 #ifdef SUPPORT_PROXY
2818 proxy_session = FALSE;
2819 proxy_session_failed = FALSE;
2820 if (check_proxy_protocol_host())
2821 setup_proxy_protocol_host();
2824 /* Start up TLS if tls_on_connect is set. This is for supporting the legacy
2825 smtps port for use with older style SSL MTAs. */
2828 if (tls_in.on_connect)
2830 if (tls_server_start(tls_require_ciphers, &user_msg) != OK)
2831 return smtp_log_tls_fail(user_msg);
2832 cmd_list[CMD_LIST_TLS_AUTH].is_mail_cmd = TRUE;
2836 /* Run the connect ACL if it exists */
2839 if (acl_smtp_connect)
2842 if ((rc = acl_check(ACL_WHERE_CONNECT, NULL, acl_smtp_connect, &user_msg,
2845 (void) smtp_handle_acl_fail(ACL_WHERE_CONNECT, rc, user_msg, log_msg);
2850 /* Output the initial message for a two-way SMTP connection. It may contain
2851 newlines, which then cause a multi-line response to be given. */
2853 code = US"220"; /* Default status code */
2854 esc = US""; /* Default extended status code */
2855 esclen = 0; /* Length of esc */
2859 if (!(s = expand_string(smtp_banner)))
2860 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "Expansion of \"%s\" (smtp_banner) "
2861 "failed: %s", smtp_banner, expand_string_message);
2867 smtp_message_code(&code, &codelen, &s, NULL, TRUE);
2871 esclen = codelen - 4;
2875 /* Remove any terminating newlines; might as well remove trailing space too */
2878 while (p > s && isspace(p[-1])) p--;
2881 /* It seems that CC:Mail is braindead, and assumes that the greeting message
2882 is all contained in a single IP packet. The original code wrote out the
2883 greeting using several calls to fprint/fputc, and on busy servers this could
2884 cause it to be split over more than one packet - which caused CC:Mail to fall
2885 over when it got the second part of the greeting after sending its first
2886 command. Sigh. To try to avoid this, build the complete greeting message
2887 first, and output it in one fell swoop. This gives a better chance of it
2888 ending up as a single packet. */
2890 ss = string_get(256);
2893 do /* At least once, in case we have an empty string */
2896 uschar *linebreak = Ustrchr(p, '\n');
2897 ss = string_catn(ss, code, 3);
2901 ss = string_catn(ss, US" ", 1);
2905 len = linebreak - p;
2906 ss = string_catn(ss, US"-", 1);
2908 ss = string_catn(ss, esc, esclen);
2909 ss = string_catn(ss, p, len);
2910 ss = string_catn(ss, US"\r\n", 2);
2916 /* Before we write the banner, check that there is no input pending, unless
2917 this synchronisation check is disabled. */
2921 unsigned n = smtp_inend - smtp_inptr;
2924 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP protocol "
2925 "synchronization error (input sent without waiting for greeting): "
2926 "rejected connection from %s input=\"%s\"", host_and_ident(TRUE),
2927 string_printing(string_copyn(smtp_inptr, n)));
2928 smtp_printf("554 SMTP synchronization error\r\n", FALSE);
2932 /* Now output the banner */
2934 smtp_printf("%s", FALSE, string_from_gstring(ss));
2936 /* Attempt to see if we sent the banner before the last ACK of the 3-way
2937 handshake arrived. If so we must have managed a TFO. */
2950 /*************************************************
2951 * Handle SMTP syntax and protocol errors *
2952 *************************************************/
2954 /* Write to the log for SMTP syntax errors in incoming commands, if configured
2955 to do so. Then transmit the error response. The return value depends on the
2956 number of syntax and protocol errors in this SMTP session.
2959 type error type, given as a log flag bit
2960 code response code; <= 0 means don't send a response
2961 data data to reflect in the response (can be NULL)
2962 errmess the error message
2964 Returns: -1 limit of syntax/protocol errors NOT exceeded
2965 +1 limit of syntax/protocol errors IS exceeded
2967 These values fit in with the values of the "done" variable in the main
2968 processing loop in smtp_setup_msg(). */
2971 synprot_error(int type, int code, uschar *data, uschar *errmess)
2975 log_write(type, LOG_MAIN, "SMTP %s error in \"%s\" %s %s",
2976 (type == L_smtp_syntax_error)? "syntax" : "protocol",
2977 string_printing(smtp_cmd_buffer), host_and_ident(TRUE), errmess);
2979 if (++synprot_error_count > smtp_max_synprot_errors)
2982 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
2983 "syntax or protocol errors (last command was \"%s\")",
2984 host_and_ident(FALSE), string_printing(smtp_cmd_buffer));
2989 smtp_printf("%d%c%s%s%s\r\n", FALSE, code, yield == 1 ? '-' : ' ',
2990 data ? data : US"", data ? US": " : US"", errmess);
2992 smtp_printf("%d Too many syntax or protocol errors\r\n", FALSE, code);
3001 /*************************************************
3002 * Send SMTP response, possibly multiline *
3003 *************************************************/
3005 /* There are, it seems, broken clients out there that cannot handle multiline
3006 responses. If no_multiline_responses is TRUE (it can be set from an ACL), we
3007 output nothing for non-final calls, and only the first line for anything else.
3010 code SMTP code, may involve extended status codes
3011 codelen length of smtp code; if > 4 there's an ESC
3012 final FALSE if the last line isn't the final line
3013 msg message text, possibly containing newlines
3019 smtp_respond(uschar* code, int codelen, BOOL final, uschar *msg)
3024 if (!final && no_multiline_responses) return;
3029 esclen = codelen - 4;
3032 /* If this is the first output for a (non-batch) RCPT command, see if all RCPTs
3033 have had the same. Note: this code is also present in smtp_printf(). It would
3034 be tidier to have it only in one place, but when it was added, it was easier to
3035 do it that way, so as not to have to mess with the code for the RCPT command,
3036 which sometimes uses smtp_printf() and sometimes smtp_respond(). */
3038 if (rcpt_in_progress)
3040 if (rcpt_smtp_response == NULL)
3041 rcpt_smtp_response = string_copy(msg);
3042 else if (rcpt_smtp_response_same &&
3043 Ustrcmp(rcpt_smtp_response, msg) != 0)
3044 rcpt_smtp_response_same = FALSE;
3045 rcpt_in_progress = FALSE;
3048 /* Now output the message, splitting it up into multiple lines if necessary.
3049 We only handle pipelining these responses as far as nonfinal/final groups,
3050 not the whole MAIL/RCPT/DATA response set. */
3054 uschar *nl = Ustrchr(msg, '\n');
3057 smtp_printf("%.3s%c%.*s%s\r\n", !final, code, final ? ' ':'-', esclen, esc, msg);
3060 else if (nl[1] == 0 || no_multiline_responses)
3062 smtp_printf("%.3s%c%.*s%.*s\r\n", !final, code, final ? ' ':'-', esclen, esc,
3063 (int)(nl - msg), msg);
3068 smtp_printf("%.3s-%.*s%.*s\r\n", TRUE, code, esclen, esc, (int)(nl - msg), msg);
3070 while (isspace(*msg)) msg++;
3078 /*************************************************
3079 * Parse user SMTP message *
3080 *************************************************/
3082 /* This function allows for user messages overriding the response code details
3083 by providing a suitable response code string at the start of the message
3084 user_msg. Check the message for starting with a response code and optionally an
3085 extended status code. If found, check that the first digit is valid, and if so,
3086 change the code pointer and length to use the replacement. An invalid code
3087 causes a panic log; in this case, if the log messages is the same as the user
3088 message, we must also adjust the value of the log message to show the code that
3089 is actually going to be used (the original one).
3091 This function is global because it is called from receive.c as well as within
3094 Note that the code length returned includes the terminating whitespace
3095 character, which is always included in the regex match.
3098 code SMTP code, may involve extended status codes
3099 codelen length of smtp code; if > 4 there's an ESC
3101 log_msg optional log message, to be adjusted with the new SMTP code
3102 check_valid if true, verify the response code
3108 smtp_message_code(uschar **code, int *codelen, uschar **msg, uschar **log_msg,
3114 if (!msg || !*msg) return;
3116 if ((n = pcre_exec(regex_smtp_code, NULL, CS *msg, Ustrlen(*msg), 0,
3117 PCRE_EOPT, ovector, sizeof(ovector)/sizeof(int))) < 0) return;
3119 if (check_valid && (*msg)[0] != (*code)[0])
3121 log_write(0, LOG_MAIN|LOG_PANIC, "configured error code starts with "
3122 "incorrect digit (expected %c) in \"%s\"", (*code)[0], *msg);
3123 if (log_msg != NULL && *log_msg == *msg)
3124 *log_msg = string_sprintf("%s %s", *code, *log_msg + ovector[1]);
3129 *codelen = ovector[1]; /* Includes final space */
3131 *msg += ovector[1]; /* Chop the code off the message */
3138 /*************************************************
3139 * Handle an ACL failure *
3140 *************************************************/
3142 /* This function is called when acl_check() fails. As well as calls from within
3143 this module, it is called from receive.c for an ACL after DATA. It sorts out
3144 logging the incident, and sends the error response. A message containing
3145 newlines is turned into a multiline SMTP response, but for logging, only the
3148 There's a table of default permanent failure response codes to use in
3149 globals.c, along with the table of names. VFRY is special. Despite RFC1123 it
3150 defaults disabled in Exim. However, discussion in connection with RFC 821bis
3151 (aka RFC 2821) has concluded that the response should be 252 in the disabled
3152 state, because there are broken clients that try VRFY before RCPT. A 5xx
3153 response should be given only when the address is positively known to be
3154 undeliverable. Sigh. We return 252 if there is no VRFY ACL or it provides
3155 no explicit code, but if there is one we let it know best.
3156 Also, for ETRN, 458 is given on refusal, and for AUTH, 503.
3158 From Exim 4.63, it is possible to override the response code details by
3159 providing a suitable response code string at the start of the message provided
3160 in user_msg. The code's first digit is checked for validity.
3163 where where the ACL was called from
3165 user_msg a message that can be included in an SMTP response
3166 log_msg a message for logging
3168 Returns: 0 in most cases
3169 2 if the failure code was FAIL_DROP, in which case the
3170 SMTP connection should be dropped (this value fits with the
3171 "done" variable in smtp_setup_msg() below)
3175 smtp_handle_acl_fail(int where, int rc, uschar *user_msg, uschar *log_msg)
3177 BOOL drop = rc == FAIL_DROP;
3181 uschar *sender_info = US"";
3183 #ifdef WITH_CONTENT_SCAN
3184 where == ACL_WHERE_MIME ? US"during MIME ACL checks" :
3186 where == ACL_WHERE_PREDATA ? US"DATA" :
3187 where == ACL_WHERE_DATA ? US"after DATA" :
3188 #ifndef DISABLE_PRDR
3189 where == ACL_WHERE_PRDR ? US"after DATA PRDR" :
3192 string_sprintf("%s %s", acl_wherenames[where], smtp_cmd_data) :
3193 string_sprintf("%s in \"connect\" ACL", acl_wherenames[where]);
3195 if (drop) rc = FAIL;
3197 /* Set the default SMTP code, and allow a user message to change it. */
3199 smtp_code = rc == FAIL ? acl_wherecodes[where] : US"451";
3200 smtp_message_code(&smtp_code, &codelen, &user_msg, &log_msg,
3201 where != ACL_WHERE_VRFY);
3203 /* We used to have sender_address here; however, there was a bug that was not
3204 updating sender_address after a rewrite during a verify. When this bug was
3205 fixed, sender_address at this point became the rewritten address. I'm not sure
3206 this is what should be logged, so I've changed to logging the unrewritten
3207 address to retain backward compatibility. */
3209 #ifndef WITH_CONTENT_SCAN
3210 if (where == ACL_WHERE_RCPT || where == ACL_WHERE_DATA)
3212 if (where == ACL_WHERE_RCPT || where == ACL_WHERE_DATA || where == ACL_WHERE_MIME)
3215 sender_info = string_sprintf("F=<%s>%s%s%s%s ",
3216 sender_address_unrewritten ? sender_address_unrewritten : sender_address,
3217 sender_host_authenticated ? US" A=" : US"",
3218 sender_host_authenticated ? sender_host_authenticated : US"",
3219 sender_host_authenticated && authenticated_id ? US":" : US"",
3220 sender_host_authenticated && authenticated_id ? authenticated_id : US""
3224 /* If there's been a sender verification failure with a specific message, and
3225 we have not sent a response about it yet, do so now, as a preliminary line for
3226 failures, but not defers. However, always log it for defer, and log it for fail
3227 unless the sender_verify_fail log selector has been turned off. */
3229 if (sender_verified_failed &&
3230 !testflag(sender_verified_failed, af_sverify_told))
3232 BOOL save_rcpt_in_progress = rcpt_in_progress;
3233 rcpt_in_progress = FALSE; /* So as not to treat these as the error */
3235 setflag(sender_verified_failed, af_sverify_told);
3237 if (rc != FAIL || LOGGING(sender_verify_fail))
3238 log_write(0, LOG_MAIN|LOG_REJECT, "%s sender verify %s for <%s>%s",
3239 host_and_ident(TRUE),
3240 ((sender_verified_failed->special_action & 255) == DEFER)? "defer":"fail",
3241 sender_verified_failed->address,
3242 (sender_verified_failed->message == NULL)? US"" :
3243 string_sprintf(": %s", sender_verified_failed->message));
3245 if (rc == FAIL && sender_verified_failed->user_message)
3246 smtp_respond(smtp_code, codelen, FALSE, string_sprintf(
3247 testflag(sender_verified_failed, af_verify_pmfail)?
3248 "Postmaster verification failed while checking <%s>\n%s\n"
3249 "Several RFCs state that you are required to have a postmaster\n"
3250 "mailbox for each mail domain. This host does not accept mail\n"
3251 "from domains whose servers reject the postmaster address."
3253 testflag(sender_verified_failed, af_verify_nsfail)?
3254 "Callback setup failed while verifying <%s>\n%s\n"
3255 "The initial connection, or a HELO or MAIL FROM:<> command was\n"
3256 "rejected. Refusing MAIL FROM:<> does not help fight spam, disregards\n"
3257 "RFC requirements, and stops you from receiving standard bounce\n"
3258 "messages. This host does not accept mail from domains whose servers\n"
3261 "Verification failed for <%s>\n%s",
3262 sender_verified_failed->address,
3263 sender_verified_failed->user_message));
3265 rcpt_in_progress = save_rcpt_in_progress;
3268 /* Sort out text for logging */
3270 log_msg = log_msg ? string_sprintf(": %s", log_msg) : US"";
3271 if ((lognl = Ustrchr(log_msg, '\n'))) *lognl = 0;
3273 /* Send permanent failure response to the command, but the code used isn't
3274 always a 5xx one - see comments at the start of this function. If the original
3275 rc was FAIL_DROP we drop the connection and yield 2. */
3278 smtp_respond(smtp_code, codelen, TRUE,
3279 user_msg ? user_msg : US"Administrative prohibition");
3281 /* Send temporary failure response to the command. Don't give any details,
3282 unless acl_temp_details is set. This is TRUE for a callout defer, a "defer"
3283 verb, and for a header verify when smtp_return_error_details is set.
3285 This conditional logic is all somewhat of a mess because of the odd
3286 interactions between temp_details and return_error_details. One day it should
3287 be re-implemented in a tidier fashion. */
3290 if (acl_temp_details && user_msg)
3292 if ( smtp_return_error_details
3293 && sender_verified_failed
3294 && sender_verified_failed->message
3296 smtp_respond(smtp_code, codelen, FALSE, sender_verified_failed->message);
3298 smtp_respond(smtp_code, codelen, TRUE, user_msg);
3301 smtp_respond(smtp_code, codelen, TRUE,
3302 US"Temporary local problem - please try later");
3304 /* Log the incident to the logs that are specified by log_reject_target
3305 (default main, reject). This can be empty to suppress logging of rejections. If
3306 the connection is not forcibly to be dropped, return 0. Otherwise, log why it
3307 is closing if required and return 2. */
3309 if (log_reject_target != 0)
3312 gstring * g = s_tlslog(NULL);
3313 uschar * tls = string_from_gstring(g);
3314 if (!tls) tls = US"";
3316 uschar * tls = US"";
3318 log_write(where == ACL_WHERE_CONNECT ? L_connection_reject : 0,
3319 log_reject_target, "%s%s%s %s%srejected %s%s",
3320 LOGGING(dnssec) && sender_host_dnssec ? US" DS" : US"",
3321 host_and_ident(TRUE),
3324 rc == FAIL ? US"" : US"temporarily ",
3328 if (!drop) return 0;
3330 log_write(L_smtp_connection, LOG_MAIN, "%s closed by DROP in ACL",
3331 smtp_get_connection_info());
3333 /* Run the not-quit ACL, but without any custom messages. This should not be a
3334 problem, because we get here only if some other ACL has issued "drop", and
3335 in that case, *its* custom messages will have been used above. */
3337 smtp_notquit_exit(US"acl-drop", NULL, NULL);
3344 /*************************************************
3345 * Handle SMTP exit when QUIT is not given *
3346 *************************************************/
3348 /* This function provides a logging/statistics hook for when an SMTP connection
3349 is dropped on the floor or the other end goes away. It's a global function
3350 because it's called from receive.c as well as this module. As well as running
3351 the NOTQUIT ACL, if there is one, this function also outputs a final SMTP
3352 response, either with a custom message from the ACL, or using a default. There
3353 is one case, however, when no message is output - after "drop". In that case,
3354 the ACL that obeyed "drop" has already supplied the custom message, and NULL is
3355 passed to this function.
3357 In case things go wrong while processing this function, causing an error that
3358 may re-enter this function, there is a recursion check.
3361 reason What $smtp_notquit_reason will be set to in the ACL;
3362 if NULL, the ACL is not run
3363 code The error code to return as part of the response
3364 defaultrespond The default message if there's no user_msg
3370 smtp_notquit_exit(uschar *reason, uschar *code, uschar *defaultrespond, ...)
3373 uschar *user_msg = NULL;
3374 uschar *log_msg = NULL;
3376 /* Check for recursive acll */
3378 if (smtp_exit_function_called)
3380 log_write(0, LOG_PANIC, "smtp_notquit_exit() called more than once (%s)",
3384 smtp_exit_function_called = TRUE;
3386 /* Call the not-QUIT ACL, if there is one, unless no reason is given. */
3388 if (acl_smtp_notquit && reason)
3390 smtp_notquit_reason = reason;
3391 if ((rc = acl_check(ACL_WHERE_NOTQUIT, NULL, acl_smtp_notquit, &user_msg,
3392 &log_msg)) == ERROR)
3393 log_write(0, LOG_MAIN|LOG_PANIC, "ACL for not-QUIT returned ERROR: %s",
3397 /* Write an SMTP response if we are expected to give one. As the default
3398 responses are all internal, they should always fit in the buffer, but code a
3399 warning, just in case. Note that string_vformat() still leaves a complete
3400 string, even if it is incomplete. */
3402 if (code && defaultrespond)
3405 smtp_respond(code, 3, TRUE, user_msg);
3410 va_start(ap, defaultrespond);
3411 if (!string_vformat(buffer, sizeof(buffer), CS defaultrespond, ap))
3412 log_write(0, LOG_MAIN|LOG_PANIC, "string too large in smtp_notquit_exit()");
3413 smtp_printf("%s %s\r\n", FALSE, code, buffer);
3423 /*************************************************
3424 * Verify HELO argument *
3425 *************************************************/
3427 /* This function is called if helo_verify_hosts or helo_try_verify_hosts is
3428 matched. It is also called from ACL processing if verify = helo is used and
3429 verification was not previously tried (i.e. helo_try_verify_hosts was not
3430 matched). The result of its processing is to set helo_verified and
3431 helo_verify_failed. These variables should both be FALSE for this function to
3434 Note that EHLO/HELO is legitimately allowed to quote an address literal. Allow
3435 for IPv6 ::ffff: literals.
3438 Returns: TRUE if testing was completed;
3439 FALSE on a temporary failure
3443 smtp_verify_helo(void)
3447 HDEBUG(D_receive) debug_printf("verifying EHLO/HELO argument \"%s\"\n",
3450 if (sender_helo_name == NULL)
3452 HDEBUG(D_receive) debug_printf("no EHLO/HELO command was issued\n");
3455 /* Deal with the case of -bs without an IP address */
3457 else if (sender_host_address == NULL)
3459 HDEBUG(D_receive) debug_printf("no client IP address: assume success\n");
3460 helo_verified = TRUE;
3463 /* Deal with the more common case when there is a sending IP address */
3465 else if (sender_helo_name[0] == '[')
3467 helo_verified = Ustrncmp(sender_helo_name+1, sender_host_address,
3468 Ustrlen(sender_host_address)) == 0;
3473 if (strncmpic(sender_host_address, US"::ffff:", 7) == 0)
3474 helo_verified = Ustrncmp(sender_helo_name + 1,
3475 sender_host_address + 7, Ustrlen(sender_host_address) - 7) == 0;
3480 { if (helo_verified) debug_printf("matched host address\n"); }
3483 /* Do a reverse lookup if one hasn't already given a positive or negative
3484 response. If that fails, or the name doesn't match, try checking with a forward
3489 if (sender_host_name == NULL && !host_lookup_failed)
3490 yield = host_name_lookup() != DEFER;
3492 /* If a host name is known, check it and all its aliases. */
3494 if (sender_host_name)
3495 if ((helo_verified = strcmpic(sender_host_name, sender_helo_name) == 0))
3497 sender_helo_dnssec = sender_host_dnssec;
3498 HDEBUG(D_receive) debug_printf("matched host name\n");
3502 uschar **aliases = sender_host_aliases;
3504 if ((helo_verified = strcmpic(*aliases++, sender_helo_name) == 0))
3506 sender_helo_dnssec = sender_host_dnssec;
3510 HDEBUG(D_receive) if (helo_verified)
3511 debug_printf("matched alias %s\n", *(--aliases));
3514 /* Final attempt: try a forward lookup of the helo name */
3523 h.name = sender_helo_name;
3530 HDEBUG(D_receive) debug_printf("getting IP address for %s\n",
3532 rc = host_find_bydns(&h, NULL, HOST_FIND_BY_A | HOST_FIND_BY_AAAA,
3533 NULL, NULL, NULL, &d, NULL, NULL);
3534 if (rc == HOST_FOUND || rc == HOST_FOUND_LOCAL)
3535 for (hh = &h; hh; hh = hh->next)
3536 if (Ustrcmp(hh->address, sender_host_address) == 0)
3538 helo_verified = TRUE;
3539 if (h.dnssec == DS_YES) sender_helo_dnssec = TRUE;
3542 debug_printf("IP address for %s matches calling address\n"
3543 "Forward DNS security status: %sverified\n",
3544 sender_helo_name, sender_helo_dnssec ? "" : "un");
3551 if (!helo_verified) helo_verify_failed = TRUE; /* We've tried ... */
3558 /*************************************************
3559 * Send user response message *
3560 *************************************************/
3562 /* This function is passed a default response code and a user message. It calls
3563 smtp_message_code() to check and possibly modify the response code, and then
3564 calls smtp_respond() to transmit the response. I put this into a function
3565 just to avoid a lot of repetition.
3568 code the response code
3569 user_msg the user message
3575 smtp_user_msg(uschar *code, uschar *user_msg)
3578 smtp_message_code(&code, &len, &user_msg, NULL, TRUE);
3579 smtp_respond(code, len, TRUE, user_msg);
3585 smtp_in_auth(auth_instance *au, uschar ** s, uschar ** ss)
3587 const uschar *set_id = NULL;
3590 /* Run the checking code, passing the remainder of the command line as
3591 data. Initials the $auth<n> variables as empty. Initialize $0 empty and set
3592 it as the only set numerical variable. The authenticator may set $auth<n>
3593 and also set other numeric variables. The $auth<n> variables are preferred
3594 nowadays; the numerical variables remain for backwards compatibility.
3596 Afterwards, have a go at expanding the set_id string, even if
3597 authentication failed - for bad passwords it can be useful to log the
3598 userid. On success, require set_id to expand and exist, and put it in
3599 authenticated_id. Save this in permanent store, as the working store gets
3600 reset at HELO, RSET, etc. */
3602 for (i = 0; i < AUTH_VARS; i++) auth_vars[i] = NULL;
3604 expand_nlength[0] = 0; /* $0 contains nothing */
3606 rc = (au->info->servercode)(au, smtp_cmd_data);
3607 if (au->set_id) set_id = expand_string(au->set_id);
3608 expand_nmax = -1; /* Reset numeric variables */
3609 for (i = 0; i < AUTH_VARS; i++) auth_vars[i] = NULL; /* Reset $auth<n> */
3611 /* The value of authenticated_id is stored in the spool file and printed in
3612 log lines. It must not contain binary zeros or newline characters. In
3613 normal use, it never will, but when playing around or testing, this error
3614 can (did) happen. To guard against this, ensure that the id contains only
3615 printing characters. */
3617 if (set_id) set_id = string_printing(set_id);
3619 /* For the non-OK cases, set up additional logging data if set_id
3623 set_id = set_id && *set_id
3624 ? string_sprintf(" (set_id=%s)", set_id) : US"";
3626 /* Switch on the result */
3631 if (!au->set_id || set_id) /* Complete success */
3633 if (set_id) authenticated_id = string_copy_malloc(set_id);
3634 sender_host_authenticated = au->name;
3635 sender_host_auth_pubname = au->public_name;
3636 authentication_failed = FALSE;
3637 authenticated_fail_id = NULL; /* Impossible to already be set? */
3640 (sender_host_address ? protocols : protocols_local)
3641 [pextend + pauthed + (tls_in.active >= 0 ? pcrpted:0)];
3642 *s = *ss = US"235 Authentication succeeded";
3643 authenticated_by = au;
3647 /* Authentication succeeded, but we failed to expand the set_id string.
3648 Treat this as a temporary error. */
3650 auth_defer_msg = expand_string_message;
3654 if (set_id) authenticated_fail_id = string_copy_malloc(set_id);
3655 *s = string_sprintf("435 Unable to authenticate at present%s",
3656 auth_defer_user_msg);
3657 *ss = string_sprintf("435 Unable to authenticate at present%s: %s",
3658 set_id, auth_defer_msg);
3662 *s = *ss = US"501 Invalid base64 data";
3666 *s = *ss = US"501 Authentication cancelled";
3670 *s = *ss = US"553 Initial data not expected";
3674 if (set_id) authenticated_fail_id = string_copy_malloc(set_id);
3675 *s = US"535 Incorrect authentication data";
3676 *ss = string_sprintf("535 Incorrect authentication data%s", set_id);
3680 if (set_id) authenticated_fail_id = string_copy_malloc(set_id);
3681 *s = US"435 Internal error";
3682 *ss = string_sprintf("435 Internal error%s: return %d from authentication "
3683 "check", set_id, rc);
3695 qualify_recipient(uschar ** recipient, uschar * smtp_cmd_data, uschar * tag)
3698 if (allow_unqualified_recipient || strcmpic(*recipient, US"postmaster") == 0)
3700 DEBUG(D_receive) debug_printf("unqualified address %s accepted\n",
3702 rd = Ustrlen(recipient) + 1;
3703 *recipient = rewrite_address_qualify(*recipient, TRUE);
3706 smtp_printf("501 %s: recipient address must contain a domain\r\n", FALSE,
3708 log_write(L_smtp_syntax_error,
3709 LOG_MAIN|LOG_REJECT, "unqualified %s rejected: <%s> %s%s",
3710 tag, *recipient, host_and_ident(TRUE), host_lookup_msg);
3718 smtp_quit_handler(uschar ** user_msgp, uschar ** log_msgp)
3721 incomplete_transaction_log(US"QUIT");
3724 int rc = acl_check(ACL_WHERE_QUIT, NULL, acl_smtp_quit, user_msgp, log_msgp);
3726 log_write(0, LOG_MAIN|LOG_PANIC, "ACL for QUIT returned ERROR: %s",
3730 smtp_respond(US"221", 3, TRUE, *user_msgp);
3732 smtp_printf("221 %s closing connection\r\n", FALSE, smtp_active_hostname);
3735 tls_close(TRUE, TLS_SHUTDOWN_NOWAIT);
3738 log_write(L_smtp_connection, LOG_MAIN, "%s closed by QUIT",
3739 smtp_get_connection_info());
3744 smtp_rset_handler(void)
3747 incomplete_transaction_log(US"RSET");
3748 smtp_printf("250 Reset OK\r\n", FALSE);
3749 cmd_list[CMD_LIST_RSET].is_mail_cmd = FALSE;
3754 /*************************************************
3755 * Initialize for SMTP incoming message *
3756 *************************************************/
3758 /* This function conducts the initial dialogue at the start of an incoming SMTP
3759 message, and builds a list of recipients. However, if the incoming message
3760 is part of a batch (-bS option) a separate function is called since it would
3761 be messy having tests splattered about all over this function. This function
3762 therefore handles the case where interaction is occurring. The input and output
3763 files are set up in smtp_in and smtp_out.
3765 The global recipients_list is set to point to a vector of recipient_item
3766 blocks, whose number is given by recipients_count. This is extended by the
3767 receive_add_recipient() function. The global variable sender_address is set to
3768 the sender's address. The yield is +1 if a message has been successfully
3769 started, 0 if a QUIT command was encountered or the connection was refused from
3770 the particular host, or -1 if the connection was lost.
3774 Returns: > 0 message successfully started (reached DATA)
3775 = 0 QUIT read or end of file reached or call refused
3780 smtp_setup_msg(void)
3783 BOOL toomany = FALSE;
3784 BOOL discarded = FALSE;
3785 BOOL last_was_rej_mail = FALSE;
3786 BOOL last_was_rcpt = FALSE;
3787 void *reset_point = store_get(0);
3789 DEBUG(D_receive) debug_printf("smtp_setup_msg entered\n");
3791 /* Reset for start of new message. We allow one RSET not to be counted as a
3792 nonmail command, for those MTAs that insist on sending it between every
3793 message. Ditto for EHLO/HELO and for STARTTLS, to allow for going in and out of
3794 TLS between messages (an Exim client may do this if it has messages queued up
3795 for the host). Note: we do NOT reset AUTH at this point. */
3797 smtp_reset(reset_point);
3798 message_ended = END_NOTSTARTED;
3800 chunking_state = chunking_offered ? CHUNKING_OFFERED : CHUNKING_NOT_OFFERED;
3802 cmd_list[CMD_LIST_RSET].is_mail_cmd = TRUE;
3803 cmd_list[CMD_LIST_HELO].is_mail_cmd = TRUE;
3804 cmd_list[CMD_LIST_EHLO].is_mail_cmd = TRUE;
3806 cmd_list[CMD_LIST_STARTTLS].is_mail_cmd = TRUE;
3809 /* Set the local signal handler for SIGTERM - it tries to end off tidily */
3811 os_non_restarting_signal(SIGTERM, command_sigterm_handler);
3813 /* Batched SMTP is handled in a different function. */
3815 if (smtp_batched_input) return smtp_setup_batch_msg();
3817 /* Deal with SMTP commands. This loop is exited by setting done to a POSITIVE
3818 value. The values are 2 larger than the required yield of the function. */
3822 const uschar **argv;
3823 uschar *etrn_command;
3824 uschar *etrn_serialize_key;
3826 uschar *log_msg, *smtp_code;
3827 uschar *user_msg = NULL;
3828 uschar *recipient = NULL;
3829 uschar *hello = NULL;
3831 BOOL was_rej_mail = FALSE;
3832 BOOL was_rcpt = FALSE;
3833 void (*oldsignal)(int);
3835 int start, end, sender_domain, recipient_domain;
3839 uschar *orcpt = NULL;
3844 /* Check once per STARTTLS or SSL-on-connect for a TLS AUTH */
3845 if ( tls_in.active >= 0
3847 && tls_in.certificate_verified
3848 && cmd_list[CMD_LIST_TLS_AUTH].is_mail_cmd
3851 cmd_list[CMD_LIST_TLS_AUTH].is_mail_cmd = FALSE;
3853 for (au = auths; au; au = au->next)
3854 if (strcmpic(US"tls", au->driver_name) == 0)
3857 && (rc = acl_check(ACL_WHERE_AUTH, NULL, acl_smtp_auth,
3858 &user_msg, &log_msg)) != OK
3860 done = smtp_handle_acl_fail(ACL_WHERE_AUTH, rc, user_msg, log_msg);
3863 smtp_cmd_data = NULL;
3865 if (smtp_in_auth(au, &s, &ss) == OK)
3866 { DEBUG(D_auth) debug_printf("tls auth succeeded\n"); }
3868 { DEBUG(D_auth) debug_printf("tls auth not succeeded\n"); }
3876 if (smtp_in) /* Avoid pure-ACKs while in cmd pingpong phase */
3877 (void) setsockopt(fileno(smtp_in), IPPROTO_TCP, TCP_QUICKACK,
3878 US &off, sizeof(off));
3881 switch(smtp_read_command(TRUE, GETC_BUFFER_UNLIMITED))
3883 /* The AUTH command is not permitted to occur inside a transaction, and may
3884 occur successfully only once per connection. Actually, that isn't quite
3885 true. When TLS is started, all previous information about a connection must
3886 be discarded, so a new AUTH is permitted at that time.
3888 AUTH may only be used when it has been advertised. However, it seems that
3889 there are clients that send AUTH when it hasn't been advertised, some of
3890 them even doing this after HELO. And there are MTAs that accept this. Sigh.
3891 So there's a get-out that allows this to happen.
3893 AUTH is initially labelled as a "nonmail command" so that one occurrence
3894 doesn't get counted. We change the label here so that multiple failing
3895 AUTHS will eventually hit the nonmail threshold. */
3899 authentication_failed = TRUE;
3900 cmd_list[CMD_LIST_AUTH].is_mail_cmd = FALSE;
3902 if (!auth_advertised && !allow_auth_unadvertised)
3904 done = synprot_error(L_smtp_protocol_error, 503, NULL,
3905 US"AUTH command used when not advertised");
3908 if (sender_host_authenticated)
3910 done = synprot_error(L_smtp_protocol_error, 503, NULL,
3911 US"already authenticated");
3916 done = synprot_error(L_smtp_protocol_error, 503, NULL,
3917 US"not permitted in mail transaction");
3924 && (rc = acl_check(ACL_WHERE_AUTH, NULL, acl_smtp_auth,
3925 &user_msg, &log_msg)) != OK
3928 done = smtp_handle_acl_fail(ACL_WHERE_AUTH, rc, user_msg, log_msg);
3932 /* Find the name of the requested authentication mechanism. */
3935 while ((c = *smtp_cmd_data) != 0 && !isspace(c))
3937 if (!isalnum(c) && c != '-' && c != '_')
3939 done = synprot_error(L_smtp_syntax_error, 501, NULL,
3940 US"invalid character in authentication mechanism name");
3946 /* If not at the end of the line, we must be at white space. Terminate the
3947 name and move the pointer on to any data that may be present. */
3949 if (*smtp_cmd_data != 0)
3951 *smtp_cmd_data++ = 0;
3952 while (isspace(*smtp_cmd_data)) smtp_cmd_data++;
3955 /* Search for an authentication mechanism which is configured for use
3956 as a server and which has been advertised (unless, sigh, allow_auth_
3957 unadvertised is set). */
3959 for (au = auths; au; au = au->next)
3960 if (strcmpic(s, au->public_name) == 0 && au->server &&
3961 (au->advertised || allow_auth_unadvertised))
3966 c = smtp_in_auth(au, &s, &ss);
3968 smtp_printf("%s\r\n", FALSE, s);
3970 log_write(0, LOG_MAIN|LOG_REJECT, "%s authenticator failed for %s: %s",
3971 au->name, host_and_ident(FALSE), ss);
3974 done = synprot_error(L_smtp_protocol_error, 504, NULL,
3975 string_sprintf("%s authentication mechanism not supported", s));
3977 break; /* AUTH_CMD */
3979 /* The HELO/EHLO commands are permitted to appear in the middle of a
3980 session as well as at the beginning. They have the effect of a reset in
3981 addition to their other functions. Their absence at the start cannot be
3982 taken to be an error.
3986 If the EHLO command is not acceptable to the SMTP server, 501, 500,
3987 or 502 failure replies MUST be returned as appropriate. The SMTP
3988 server MUST stay in the same state after transmitting these replies
3989 that it was in before the EHLO was received.
3991 Therefore, we do not do the reset until after checking the command for
3992 acceptability. This change was made for Exim release 4.11. Previously
3993 it did the reset first. */
4006 HELO_EHLO: /* Common code for HELO and EHLO */
4007 cmd_list[CMD_LIST_HELO].is_mail_cmd = FALSE;
4008 cmd_list[CMD_LIST_EHLO].is_mail_cmd = FALSE;
4010 /* Reject the HELO if its argument was invalid or non-existent. A
4011 successful check causes the argument to be saved in malloc store. */
4013 if (!check_helo(smtp_cmd_data))
4015 smtp_printf("501 Syntactically invalid %s argument(s)\r\n", FALSE, hello);
4017 log_write(0, LOG_MAIN|LOG_REJECT, "rejected %s from %s: syntactically "
4018 "invalid argument(s): %s", hello, host_and_ident(FALSE),
4019 (*smtp_cmd_argument == 0)? US"(no argument given)" :
4020 string_printing(smtp_cmd_argument));
4022 if (++synprot_error_count > smtp_max_synprot_errors)
4024 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
4025 "syntax or protocol errors (last command was \"%s\")",
4026 host_and_ident(FALSE), string_printing(smtp_cmd_buffer));
4033 /* If sender_host_unknown is true, we have got here via the -bs interface,
4034 not called from inetd. Otherwise, we are running an IP connection and the
4035 host address will be set. If the helo name is the primary name of this
4036 host and we haven't done a reverse lookup, force one now. If helo_required
4037 is set, ensure that the HELO name matches the actual host. If helo_verify
4038 is set, do the same check, but softly. */
4040 if (!sender_host_unknown)
4042 BOOL old_helo_verified = helo_verified;
4043 uschar *p = smtp_cmd_data;
4045 while (*p != 0 && !isspace(*p)) { *p = tolower(*p); p++; }
4048 /* Force a reverse lookup if HELO quoted something in helo_lookup_domains
4049 because otherwise the log can be confusing. */
4051 if ( !sender_host_name
4052 && (deliver_domain = sender_helo_name, /* set $domain */
4053 match_isinlist(sender_helo_name, CUSS &helo_lookup_domains, 0,
4054 &domainlist_anchor, NULL, MCL_DOMAIN, TRUE, NULL)) == OK)
4055 (void)host_name_lookup();
4057 /* Rebuild the fullhost info to include the HELO name (and the real name
4058 if it was looked up.) */
4060 host_build_sender_fullhost(); /* Rebuild */
4061 set_process_info("handling%s incoming connection from %s",
4062 (tls_in.active >= 0)? " TLS" : "", host_and_ident(FALSE));
4064 /* Verify if configured. This doesn't give much security, but it does
4065 make some people happy to be able to do it. If helo_required is set,
4066 (host matches helo_verify_hosts) failure forces rejection. If helo_verify
4067 is set (host matches helo_try_verify_hosts), it does not. This is perhaps
4068 now obsolescent, since the verification can now be requested selectively
4071 helo_verified = helo_verify_failed = sender_helo_dnssec = FALSE;
4072 if (helo_required || helo_verify)
4074 BOOL tempfail = !smtp_verify_helo();
4079 smtp_printf("%d %s argument does not match calling host\r\n", FALSE,
4080 tempfail? 451 : 550, hello);
4081 log_write(0, LOG_MAIN|LOG_REJECT, "%srejected \"%s %s\" from %s",
4082 tempfail? "temporarily " : "",
4083 hello, sender_helo_name, host_and_ident(FALSE));
4084 helo_verified = old_helo_verified;
4085 break; /* End of HELO/EHLO processing */
4087 HDEBUG(D_all) debug_printf("%s verification failed but host is in "
4088 "helo_try_verify_hosts\n", hello);
4094 /* set up SPF context */
4095 spf_init(sender_helo_name, sender_host_address);
4098 /* Apply an ACL check if one is defined; afterwards, recheck
4099 synchronization in case the client started sending in a delay. */
4102 if ((rc = acl_check(ACL_WHERE_HELO, NULL, acl_smtp_helo,
4103 &user_msg, &log_msg)) != OK)
4105 done = smtp_handle_acl_fail(ACL_WHERE_HELO, rc, user_msg, log_msg);
4106 if (sender_helo_name)
4108 store_free(sender_helo_name);
4109 sender_helo_name = NULL;
4111 host_build_sender_fullhost(); /* Rebuild */
4114 else if (!check_sync()) goto SYNC_FAILURE;
4116 /* Generate an OK reply. The default string includes the ident if present,
4117 and also the IP address if present. Reflecting back the ident is intended
4118 as a deterrent to mail forgers. For maximum efficiency, and also because
4119 some broken systems expect each response to be in a single packet, arrange
4120 that the entire reply is sent in one write(). */
4122 auth_advertised = FALSE;
4123 pipelining_advertised = FALSE;
4125 tls_advertised = FALSE;
4127 dsn_advertised = FALSE;
4129 smtputf8_advertised = FALSE;
4132 smtp_code = US"250 "; /* Default response code plus space*/
4135 s = string_sprintf("%.3s %s Hello %s%s%s",
4137 smtp_active_hostname,
4138 sender_ident ? sender_ident : US"",
4139 sender_ident ? US" at " : US"",
4140 sender_host_name ? sender_host_name : sender_helo_name);
4141 g = string_cat(NULL, s);
4143 if (sender_host_address)
4145 g = string_catn(g, US" [", 2);
4146 g = string_cat (g, sender_host_address);
4147 g = string_catn(g, US"]", 1);
4151 /* A user-supplied EHLO greeting may not contain more than one line. Note
4152 that the code returned by smtp_message_code() includes the terminating
4153 whitespace character. */
4159 smtp_message_code(&smtp_code, &codelen, &user_msg, NULL, TRUE);
4160 s = string_sprintf("%.*s%s", codelen, smtp_code, user_msg);
4161 if ((ss = strpbrk(CS s, "\r\n")) != NULL)
4163 log_write(0, LOG_MAIN|LOG_PANIC, "EHLO/HELO response must not contain "
4164 "newlines: message truncated: %s", string_printing(s));
4167 g = string_cat(NULL, s);
4170 g = string_catn(g, US"\r\n", 2);
4172 /* If we received EHLO, we must create a multiline response which includes
4173 the functions supported. */
4179 /* I'm not entirely happy with this, as an MTA is supposed to check
4180 that it has enough room to accept a message of maximum size before
4181 it sends this. However, there seems little point in not sending it.
4182 The actual size check happens later at MAIL FROM time. By postponing it
4183 till then, VRFY and EXPN can be used after EHLO when space is short. */
4185 if (thismessage_size_limit > 0)
4187 sprintf(CS big_buffer, "%.3s-SIZE %d\r\n", smtp_code,
4188 thismessage_size_limit);
4189 g = string_cat(g, big_buffer);
4193 g = string_catn(g, smtp_code, 3);
4194 g = string_catn(g, US"-SIZE\r\n", 7);
4197 /* Exim does not do protocol conversion or data conversion. It is 8-bit
4198 clean; if it has an 8-bit character in its hand, it just sends it. It
4199 cannot therefore specify 8BITMIME and remain consistent with the RFCs.
4200 However, some users want this option simply in order to stop MUAs
4201 mangling messages that contain top-bit-set characters. It is therefore
4202 provided as an option. */
4204 if (accept_8bitmime)
4206 g = string_catn(g, smtp_code, 3);
4207 g = string_catn(g, US"-8BITMIME\r\n", 11);
4210 /* Advertise DSN support if configured to do so. */
4211 if (verify_check_host(&dsn_advertise_hosts) != FAIL)
4213 g = string_catn(g, smtp_code, 3);
4214 g = string_catn(g, US"-DSN\r\n", 6);
4215 dsn_advertised = TRUE;
4218 /* Advertise ETRN/VRFY/EXPN if there's are ACL checking whether a host is
4219 permitted to issue them; a check is made when any host actually tries. */
4223 g = string_catn(g, smtp_code, 3);
4224 g = string_catn(g, US"-ETRN\r\n", 7);
4228 g = string_catn(g, smtp_code, 3);
4229 g = string_catn(g, US"-VRFY\r\n", 7);
4233 g = string_catn(g, smtp_code, 3);
4234 g = string_catn(g, US"-EXPN\r\n", 7);
4237 /* Exim is quite happy with pipelining, so let the other end know that
4238 it is safe to use it, unless advertising is disabled. */
4240 if (pipelining_enable &&
4241 verify_check_host(&pipelining_advertise_hosts) == OK)
4243 g = string_catn(g, smtp_code, 3);
4244 g = string_catn(g, US"-PIPELINING\r\n", 13);
4245 sync_cmd_limit = NON_SYNC_CMD_PIPELINING;
4246 pipelining_advertised = TRUE;
4250 /* If any server authentication mechanisms are configured, advertise
4251 them if the current host is in auth_advertise_hosts. The problem with
4252 advertising always is that some clients then require users to
4253 authenticate (and aren't configurable otherwise) even though it may not
4254 be necessary (e.g. if the host is in host_accept_relay).
4256 RFC 2222 states that SASL mechanism names contain only upper case
4257 letters, so output the names in upper case, though we actually recognize
4258 them in either case in the AUTH command. */
4262 && !sender_host_authenticated
4264 && verify_check_host(&auth_advertise_hosts) == OK
4269 for (au = auths; au; au = au->next)
4271 au->advertised = FALSE;
4274 DEBUG(D_auth+D_expand) debug_printf_indent(
4275 "Evaluating advertise_condition for %s athenticator\n",
4277 if ( !au->advertise_condition
4278 || expand_check_condition(au->advertise_condition, au->name,
4285 g = string_catn(g, smtp_code, 3);
4286 g = string_catn(g, US"-AUTH", 5);
4288 auth_advertised = TRUE;
4291 g = string_catn(g, US" ", 1);
4292 g = string_cat (g, au->public_name);
4293 while (++saveptr < g->ptr) g->s[saveptr] = toupper(g->s[saveptr]);
4294 au->advertised = TRUE;
4299 if (!first) g = string_catn(g, US"\r\n", 2);
4302 /* RFC 3030 CHUNKING */
4304 if (verify_check_host(&chunking_advertise_hosts) != FAIL)
4306 g = string_catn(g, smtp_code, 3);
4307 g = string_catn(g, US"-CHUNKING\r\n", 11);
4308 chunking_offered = TRUE;
4309 chunking_state = CHUNKING_OFFERED;
4312 /* Advertise TLS (Transport Level Security) aka SSL (Secure Socket Layer)
4313 if it has been included in the binary, and the host matches
4314 tls_advertise_hosts. We must *not* advertise if we are already in a
4315 secure connection. */
4318 if (tls_in.active < 0 &&
4319 verify_check_host(&tls_advertise_hosts) != FAIL)
4321 g = string_catn(g, smtp_code, 3);
4322 g = string_catn(g, US"-STARTTLS\r\n", 11);
4323 tls_advertised = TRUE;
4327 #ifndef DISABLE_PRDR
4328 /* Per Recipient Data Response, draft by Eric A. Hall extending RFC */
4331 g = string_catn(g, smtp_code, 3);
4332 g = string_catn(g, US"-PRDR\r\n", 7);
4337 if ( accept_8bitmime
4338 && verify_check_host(&smtputf8_advertise_hosts) != FAIL)
4340 g = string_catn(g, smtp_code, 3);
4341 g = string_catn(g, US"-SMTPUTF8\r\n", 11);
4342 smtputf8_advertised = TRUE;
4346 /* Finish off the multiline reply with one that is always available. */
4348 g = string_catn(g, smtp_code, 3);
4349 g = string_catn(g, US" HELP\r\n", 7);
4352 /* Terminate the string (for debug), write it, and note that HELO/EHLO
4356 if (tls_in.active >= 0) (void)tls_write(TRUE, g->s, g->ptr, FALSE); else
4360 int i = fwrite(g->s, 1, g->ptr, smtp_out); i = i; /* compiler quietening */
4366 (void) string_from_gstring(g);
4367 while ((cr = Ustrchr(g->s, '\r')) != NULL) /* lose CRs */
4368 memmove(cr, cr + 1, (g->ptr--) - (cr - g->s));
4369 debug_printf("SMTP>> %s", g->s);
4373 /* Reset the protocol and the state, abandoning any previous message. */
4375 (sender_host_address ? protocols : protocols_local)
4377 ? pextend + (sender_host_authenticated ? pauthed : 0)
4379 + (tls_in.active >= 0 ? pcrpted : 0)
4381 cancel_cutthrough_connection(TRUE, US"sent EHLO response");
4382 smtp_reset(reset_point);
4384 break; /* HELO/EHLO */
4387 /* The MAIL command requires an address as an operand. All we do
4388 here is to parse it for syntactic correctness. The form "<>" is
4389 a special case which converts into an empty string. The start/end
4390 pointers in the original are not used further for this address, as
4391 it is the canonical extracted address which is all that is kept. */
4395 smtp_mailcmd_count++; /* Count for limit and ratelimit */
4396 was_rej_mail = TRUE; /* Reset if accepted */
4397 env_mail_type_t * mail_args; /* Sanity check & validate args */
4399 if (helo_required && !helo_seen)
4401 smtp_printf("503 HELO or EHLO required\r\n", FALSE);
4402 log_write(0, LOG_MAIN|LOG_REJECT, "rejected MAIL from %s: no "
4403 "HELO/EHLO given", host_and_ident(FALSE));
4407 if (sender_address != NULL)
4409 done = synprot_error(L_smtp_protocol_error, 503, NULL,
4410 US"sender already given");
4414 if (smtp_cmd_data[0] == 0)
4416 done = synprot_error(L_smtp_protocol_error, 501, NULL,
4417 US"MAIL must have an address operand");
4421 /* Check to see if the limit for messages per connection would be
4422 exceeded by accepting further messages. */
4424 if (smtp_accept_max_per_connection > 0 &&
4425 smtp_mailcmd_count > smtp_accept_max_per_connection)
4427 smtp_printf("421 too many messages in this connection\r\n", FALSE);
4428 log_write(0, LOG_MAIN|LOG_REJECT, "rejected MAIL command %s: too many "
4429 "messages in one connection", host_and_ident(TRUE));
4433 /* Reset for start of message - even if this is going to fail, we
4434 obviously need to throw away any previous data. */
4436 cancel_cutthrough_connection(TRUE, US"MAIL received");
4437 smtp_reset(reset_point);
4439 sender_data = recipient_data = NULL;
4441 /* Loop, checking for ESMTP additions to the MAIL FROM command. */
4445 uschar *name, *value, *end;
4446 unsigned long int size;
4447 BOOL arg_error = FALSE;
4449 if (!extract_option(&name, &value)) break;
4451 for (mail_args = env_mail_type_list;
4452 mail_args->value != ENV_MAIL_OPT_NULL;
4455 if (strcmpic(name, mail_args->name) == 0)
4457 if (mail_args->need_value && strcmpic(value, US"") == 0)
4460 switch(mail_args->value)
4462 /* Handle SIZE= by reading the value. We don't do the check till later,
4463 in order to be able to log the sender address on failure. */
4464 case ENV_MAIL_OPT_SIZE:
4465 if (((size = Ustrtoul(value, &end, 10)), *end == 0))
4467 if ((size == ULONG_MAX && errno == ERANGE) || size > INT_MAX)
4469 message_size = (int)size;
4475 /* If this session was initiated with EHLO and accept_8bitmime is set,
4476 Exim will have indicated that it supports the BODY=8BITMIME option. In
4477 fact, it does not support this according to the RFCs, in that it does not
4478 take any special action for forwarding messages containing 8-bit
4479 characters. That is why accept_8bitmime is not the default setting, but
4480 some sites want the action that is provided. We recognize both "8BITMIME"
4481 and "7BIT" as body types, but take no action. */
4482 case ENV_MAIL_OPT_BODY:
4483 if (accept_8bitmime) {
4484 if (strcmpic(value, US"8BITMIME") == 0)
4486 else if (strcmpic(value, US"7BIT") == 0)
4491 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4492 US"invalid data for BODY");
4495 DEBUG(D_receive) debug_printf("8BITMIME: %d\n", body_8bitmime);
4501 /* Handle the two DSN options, but only if configured to do so (which
4502 will have caused "DSN" to be given in the EHLO response). The code itself
4503 is included only if configured in at build time. */
4505 case ENV_MAIL_OPT_RET:
4508 /* Check if RET has already been set */
4511 synprot_error(L_smtp_syntax_error, 501, NULL,
4512 US"RET can be specified once only");
4515 dsn_ret = strcmpic(value, US"HDRS") == 0
4517 : strcmpic(value, US"FULL") == 0
4520 DEBUG(D_receive) debug_printf("DSN_RET: %d\n", dsn_ret);
4521 /* Check for invalid invalid value, and exit with error */
4524 synprot_error(L_smtp_syntax_error, 501, NULL,
4525 US"Value for RET is invalid");
4530 case ENV_MAIL_OPT_ENVID:
4533 /* Check if the dsn envid has been already set */
4534 if (dsn_envid != NULL)
4536 synprot_error(L_smtp_syntax_error, 501, NULL,
4537 US"ENVID can be specified once only");
4540 dsn_envid = string_copy(value);
4541 DEBUG(D_receive) debug_printf("DSN_ENVID: %s\n", dsn_envid);
4545 /* Handle the AUTH extension. If the value given is not "<>" and either
4546 the ACL says "yes" or there is no ACL but the sending host is
4547 authenticated, we set it up as the authenticated sender. However, if the
4548 authenticator set a condition to be tested, we ignore AUTH on MAIL unless
4549 the condition is met. The value of AUTH is an xtext, which means that +,
4550 = and cntrl chars are coded in hex; however "<>" is unaffected by this
4552 case ENV_MAIL_OPT_AUTH:
4553 if (Ustrcmp(value, "<>") != 0)
4558 if (auth_xtextdecode(value, &authenticated_sender) < 0)
4560 /* Put back terminator overrides for error message */
4563 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4564 US"invalid data for AUTH");
4567 if (!acl_smtp_mailauth)
4569 ignore_msg = US"client not authenticated";
4570 rc = sender_host_authenticated ? OK : FAIL;
4574 ignore_msg = US"rejected by ACL";
4575 rc = acl_check(ACL_WHERE_MAILAUTH, NULL, acl_smtp_mailauth,
4576 &user_msg, &log_msg);
4582 if (authenticated_by == NULL ||
4583 authenticated_by->mail_auth_condition == NULL ||
4584 expand_check_condition(authenticated_by->mail_auth_condition,
4585 authenticated_by->name, US"authenticator"))
4586 break; /* Accept the AUTH */
4588 ignore_msg = US"server_mail_auth_condition failed";
4589 if (authenticated_id != NULL)
4590 ignore_msg = string_sprintf("%s: authenticated ID=\"%s\"",
4591 ignore_msg, authenticated_id);
4596 authenticated_sender = NULL;
4597 log_write(0, LOG_MAIN, "ignoring AUTH=%s from %s (%s)",
4598 value, host_and_ident(TRUE), ignore_msg);
4601 /* Should only get DEFER or ERROR here. Put back terminator
4602 overrides for error message */
4607 (void)smtp_handle_acl_fail(ACL_WHERE_MAILAUTH, rc, user_msg,
4614 #ifndef DISABLE_PRDR
4615 case ENV_MAIL_OPT_PRDR:
4617 prdr_requested = TRUE;
4622 case ENV_MAIL_OPT_UTF8:
4623 if (smtputf8_advertised)
4625 int old_pool = store_pool;
4627 DEBUG(D_receive) debug_printf("smtputf8 requested\n");
4628 message_smtputf8 = allow_utf8_domains = TRUE;
4629 store_pool = POOL_PERM;
4630 received_protocol = string_sprintf("utf8%s", received_protocol);
4631 store_pool = old_pool;
4635 /* No valid option. Stick back the terminator characters and break
4636 the loop. Do the name-terminator second as extract_option sets
4637 value==name when it found no equal-sign.
4638 An error for a malformed address will occur. */
4639 case ENV_MAIL_OPT_NULL:
4647 /* Break out of for loop if switch() had bad argument or
4648 when start of the email address is reached */
4649 if (arg_error) break;
4652 /* If we have passed the threshold for rate limiting, apply the current
4653 delay, and update it for next time, provided this is a limited host. */
4655 if (smtp_mailcmd_count > smtp_rlm_threshold &&
4656 verify_check_host(&smtp_ratelimit_hosts) == OK)
4658 DEBUG(D_receive) debug_printf("rate limit MAIL: delay %.3g sec\n",
4659 smtp_delay_mail/1000.0);
4660 millisleep((int)smtp_delay_mail);
4661 smtp_delay_mail *= smtp_rlm_factor;
4662 if (smtp_delay_mail > (double)smtp_rlm_limit)
4663 smtp_delay_mail = (double)smtp_rlm_limit;
4666 /* Now extract the address, first applying any SMTP-time rewriting. The
4667 TRUE flag allows "<>" as a sender address. */
4669 raw_sender = rewrite_existflags & rewrite_smtp
4670 ? rewrite_one(smtp_cmd_data, rewrite_smtp, NULL, FALSE, US"",
4671 global_rewrite_rules)
4675 parse_extract_address(raw_sender, &errmess, &start, &end, &sender_domain,
4680 done = synprot_error(L_smtp_syntax_error, 501, smtp_cmd_data, errmess);
4684 sender_address = raw_sender;
4686 /* If there is a configured size limit for mail, check that this message
4687 doesn't exceed it. The check is postponed to this point so that the sender
4690 if (thismessage_size_limit > 0 && message_size > thismessage_size_limit)
4692 smtp_printf("552 Message size exceeds maximum permitted\r\n", FALSE);
4693 log_write(L_size_reject,
4694 LOG_MAIN|LOG_REJECT, "rejected MAIL FROM:<%s> %s: "
4695 "message too big: size%s=%d max=%d",
4697 host_and_ident(TRUE),
4698 (message_size == INT_MAX)? ">" : "",
4700 thismessage_size_limit);
4701 sender_address = NULL;
4705 /* Check there is enough space on the disk unless configured not to.
4706 When smtp_check_spool_space is set, the check is for thismessage_size_limit
4707 plus the current message - i.e. we accept the message only if it won't
4708 reduce the space below the threshold. Add 5000 to the size to allow for
4709 overheads such as the Received: line and storing of recipients, etc.
4710 By putting the check here, even when SIZE is not given, it allow VRFY
4711 and EXPN etc. to be used when space is short. */
4713 if (!receive_check_fs(
4714 (smtp_check_spool_space && message_size >= 0)?
4715 message_size + 5000 : 0))
4717 smtp_printf("452 Space shortage, please try later\r\n", FALSE);
4718 sender_address = NULL;
4722 /* If sender_address is unqualified, reject it, unless this is a locally
4723 generated message, or the sending host or net is permitted to send
4724 unqualified addresses - typically local machines behaving as MUAs -
4725 in which case just qualify the address. The flag is set above at the start
4726 of the SMTP connection. */
4728 if (sender_domain == 0 && sender_address[0] != 0)
4730 if (allow_unqualified_sender)
4732 sender_domain = Ustrlen(sender_address) + 1;
4733 sender_address = rewrite_address_qualify(sender_address, FALSE);
4734 DEBUG(D_receive) debug_printf("unqualified address %s accepted\n",
4739 smtp_printf("501 %s: sender address must contain a domain\r\n", FALSE,
4741 log_write(L_smtp_syntax_error,
4742 LOG_MAIN|LOG_REJECT,
4743 "unqualified sender rejected: <%s> %s%s",
4745 host_and_ident(TRUE),
4747 sender_address = NULL;
4752 /* Apply an ACL check if one is defined, before responding. Afterwards,
4753 when pipelining is not advertised, do another sync check in case the ACL
4754 delayed and the client started sending in the meantime. */
4758 rc = acl_check(ACL_WHERE_MAIL, NULL, acl_smtp_mail, &user_msg, &log_msg);
4759 if (rc == OK && !pipelining_advertised && !check_sync())
4765 if (rc == OK || rc == DISCARD)
4767 BOOL more = pipeline_response();
4770 smtp_printf("%s%s%s", more, US"250 OK",
4771 #ifndef DISABLE_PRDR
4772 prdr_requested ? US", PRDR Requested" : US"",
4779 #ifndef DISABLE_PRDR
4781 user_msg = string_sprintf("%s%s", user_msg, US", PRDR Requested");
4783 smtp_user_msg(US"250", user_msg);
4785 smtp_delay_rcpt = smtp_rlr_base;
4786 recipients_discarded = (rc == DISCARD);
4787 was_rej_mail = FALSE;
4791 done = smtp_handle_acl_fail(ACL_WHERE_MAIL, rc, user_msg, log_msg);
4792 sender_address = NULL;
4797 /* The RCPT command requires an address as an operand. There may be any
4798 number of RCPT commands, specifying multiple recipients. We build them all
4799 into a data structure. The start/end values given by parse_extract_address
4800 are not used, as we keep only the extracted address. */
4805 was_rcpt = rcpt_in_progress = TRUE;
4807 /* There must be a sender address; if the sender was rejected and
4808 pipelining was advertised, we assume the client was pipelining, and do not
4809 count this as a protocol error. Reset was_rej_mail so that further RCPTs
4810 get the same treatment. */
4812 if (sender_address == NULL)
4814 if (pipelining_advertised && last_was_rej_mail)
4816 smtp_printf("503 sender not yet given\r\n", FALSE);
4817 was_rej_mail = TRUE;
4821 done = synprot_error(L_smtp_protocol_error, 503, NULL,
4822 US"sender not yet given");
4823 was_rcpt = FALSE; /* Not a valid RCPT */
4829 /* Check for an operand */
4831 if (smtp_cmd_data[0] == 0)
4833 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4834 US"RCPT must have an address operand");
4839 /* Set the DSN flags orcpt and dsn_flags from the session*/
4845 uschar *name, *value;
4847 if (!extract_option(&name, &value))
4850 if (dsn_advertised && strcmpic(name, US"ORCPT") == 0)
4852 /* Check whether orcpt has been already set */
4855 synprot_error(L_smtp_syntax_error, 501, NULL,
4856 US"ORCPT can be specified once only");
4859 orcpt = string_copy(value);
4860 DEBUG(D_receive) debug_printf("DSN orcpt: %s\n", orcpt);
4863 else if (dsn_advertised && strcmpic(name, US"NOTIFY") == 0)
4865 /* Check if the notify flags have been already set */
4868 synprot_error(L_smtp_syntax_error, 501, NULL,
4869 US"NOTIFY can be specified once only");
4872 if (strcmpic(value, US"NEVER") == 0)
4873 flags |= rf_notify_never;
4880 while (*pp != 0 && *pp != ',') pp++;
4881 if (*pp == ',') *pp++ = 0;
4882 if (strcmpic(p, US"SUCCESS") == 0)
4884 DEBUG(D_receive) debug_printf("DSN: Setting notify success\n");
4885 flags |= rf_notify_success;
4887 else if (strcmpic(p, US"FAILURE") == 0)
4889 DEBUG(D_receive) debug_printf("DSN: Setting notify failure\n");
4890 flags |= rf_notify_failure;
4892 else if (strcmpic(p, US"DELAY") == 0)
4894 DEBUG(D_receive) debug_printf("DSN: Setting notify delay\n");
4895 flags |= rf_notify_delay;
4899 /* Catch any strange values */
4900 synprot_error(L_smtp_syntax_error, 501, NULL,
4901 US"Invalid value for NOTIFY parameter");
4906 DEBUG(D_receive) debug_printf("DSN Flags: %x\n", flags);
4910 /* Unknown option. Stick back the terminator characters and break
4911 the loop. An error for a malformed address will occur. */
4915 DEBUG(D_receive) debug_printf("Invalid RCPT option: %s : %s\n", name, value);
4922 /* Apply SMTP rewriting then extract the working address. Don't allow "<>"
4923 as a recipient address */
4925 recipient = rewrite_existflags & rewrite_smtp
4926 ? rewrite_one(smtp_cmd_data, rewrite_smtp, NULL, FALSE, US"",
4927 global_rewrite_rules)
4930 if (!(recipient = parse_extract_address(recipient, &errmess, &start, &end,
4931 &recipient_domain, FALSE)))
4933 done = synprot_error(L_smtp_syntax_error, 501, smtp_cmd_data, errmess);
4938 /* If the recipient address is unqualified, reject it, unless this is a
4939 locally generated message. However, unqualified addresses are permitted
4940 from a configured list of hosts and nets - typically when behaving as
4941 MUAs rather than MTAs. Sad that SMTP is used for both types of traffic,
4942 really. The flag is set at the start of the SMTP connection.
4944 RFC 1123 talks about supporting "the reserved mailbox postmaster"; I always
4945 assumed this meant "reserved local part", but the revision of RFC 821 and
4946 friends now makes it absolutely clear that it means *mailbox*. Consequently
4947 we must always qualify this address, regardless. */
4949 if (!recipient_domain)
4950 if (!(recipient_domain = qualify_recipient(&recipient, smtp_cmd_data,
4957 /* Check maximum allowed */
4959 if (rcpt_count > recipients_max && recipients_max > 0)
4961 if (recipients_max_reject)
4964 smtp_printf("552 too many recipients\r\n", FALSE);
4966 log_write(0, LOG_MAIN|LOG_REJECT, "too many recipients: message "
4967 "rejected: sender=<%s> %s", sender_address, host_and_ident(TRUE));
4972 smtp_printf("452 too many recipients\r\n", FALSE);
4974 log_write(0, LOG_MAIN|LOG_REJECT, "too many recipients: excess "
4975 "temporarily rejected: sender=<%s> %s", sender_address,
4976 host_and_ident(TRUE));
4983 /* If we have passed the threshold for rate limiting, apply the current
4984 delay, and update it for next time, provided this is a limited host. */
4986 if (rcpt_count > smtp_rlr_threshold &&
4987 verify_check_host(&smtp_ratelimit_hosts) == OK)
4989 DEBUG(D_receive) debug_printf("rate limit RCPT: delay %.3g sec\n",
4990 smtp_delay_rcpt/1000.0);
4991 millisleep((int)smtp_delay_rcpt);
4992 smtp_delay_rcpt *= smtp_rlr_factor;
4993 if (smtp_delay_rcpt > (double)smtp_rlr_limit)
4994 smtp_delay_rcpt = (double)smtp_rlr_limit;
4997 /* If the MAIL ACL discarded all the recipients, we bypass ACL checking
4998 for them. Otherwise, check the access control list for this recipient. As
4999 there may be a delay in this, re-check for a synchronization error
5000 afterwards, unless pipelining was advertised. */
5002 if (recipients_discarded)
5005 if ( (rc = acl_check(ACL_WHERE_RCPT, recipient, acl_smtp_rcpt, &user_msg,
5007 && !pipelining_advertised && !check_sync())
5010 /* The ACL was happy */
5014 BOOL more = pipeline_response();
5017 smtp_user_msg(US"250", user_msg);
5019 smtp_printf("250 Accepted\r\n", more);
5020 receive_add_recipient(recipient, -1);
5022 /* Set the dsn flags in the recipients_list */
5023 recipients_list[recipients_count-1].orcpt = orcpt;
5024 recipients_list[recipients_count-1].dsn_flags = flags;
5026 DEBUG(D_receive) debug_printf("DSN: orcpt: %s flags: %d\n",
5027 recipients_list[recipients_count-1].orcpt,
5028 recipients_list[recipients_count-1].dsn_flags);
5031 /* The recipient was discarded */
5033 else if (rc == DISCARD)
5036 smtp_user_msg(US"250", user_msg);
5038 smtp_printf("250 Accepted\r\n", FALSE);
5041 log_write(0, LOG_MAIN|LOG_REJECT, "%s F=<%s> RCPT %s: "
5042 "discarded by %s ACL%s%s", host_and_ident(TRUE),
5043 sender_address_unrewritten? sender_address_unrewritten : sender_address,
5044 smtp_cmd_argument, recipients_discarded? "MAIL" : "RCPT",
5045 log_msg ? US": " : US"", log_msg ? log_msg : US"");
5048 /* Either the ACL failed the address, or it was deferred. */
5052 if (rc == FAIL) rcpt_fail_count++; else rcpt_defer_count++;
5053 done = smtp_handle_acl_fail(ACL_WHERE_RCPT, rc, user_msg, log_msg);
5058 /* The DATA command is legal only if it follows successful MAIL FROM
5059 and RCPT TO commands. However, if pipelining is advertised, a bad DATA is
5060 not counted as a protocol error if it follows RCPT (which must have been
5061 rejected if there are no recipients.) This function is complete when a
5062 valid DATA command is encountered.
5064 Note concerning the code used: RFC 2821 says this:
5066 - If there was no MAIL, or no RCPT, command, or all such commands
5067 were rejected, the server MAY return a "command out of sequence"
5068 (503) or "no valid recipients" (554) reply in response to the
5071 The example in the pipelining RFC 2920 uses 554, but I use 503 here
5072 because it is the same whether pipelining is in use or not.
5074 If all the RCPT commands that precede DATA provoked the same error message
5075 (often indicating some kind of system error), it is helpful to include it
5076 with the DATA rejection (an idea suggested by Tony Finch). */
5083 if (chunking_state != CHUNKING_OFFERED)
5085 done = synprot_error(L_smtp_protocol_error, 503, NULL,
5086 US"BDAT command used when CHUNKING not advertised");
5090 /* grab size, endmarker */
5092 if (sscanf(CS smtp_cmd_data, "%u %n", &chunking_datasize, &n) < 1)
5094 done = synprot_error(L_smtp_protocol_error, 501, NULL,
5095 US"missing size for BDAT command");
5098 chunking_state = strcmpic(smtp_cmd_data+n, US"LAST") == 0
5099 ? CHUNKING_LAST : CHUNKING_ACTIVE;
5100 chunking_data_left = chunking_datasize;
5101 DEBUG(D_receive) debug_printf("chunking state %d, %d bytes\n",
5102 (int)chunking_state, chunking_data_left);
5104 /* push the current receive_* function on the "stack", and
5105 replace them by bdat_getc(), which in turn will use the lwr_receive_*
5106 functions to do the dirty work. */
5107 lwr_receive_getc = receive_getc;
5108 lwr_receive_getbuf = receive_getbuf;
5109 lwr_receive_ungetc = receive_ungetc;
5111 receive_getc = bdat_getc;
5112 receive_ungetc = bdat_ungetc;
5123 DATA_BDAT: /* Common code for DATA and BDAT */
5124 if (!discarded && recipients_count <= 0)
5126 if (rcpt_smtp_response_same && rcpt_smtp_response != NULL)
5128 uschar *code = US"503";
5129 int len = Ustrlen(rcpt_smtp_response);
5130 smtp_respond(code, 3, FALSE, US"All RCPT commands were rejected with "
5132 /* Responses from smtp_printf() will have \r\n on the end */
5133 if (len > 2 && rcpt_smtp_response[len-2] == '\r')
5134 rcpt_smtp_response[len-2] = 0;
5135 smtp_respond(code, 3, FALSE, rcpt_smtp_response);
5137 if (pipelining_advertised && last_was_rcpt)
5138 smtp_printf("503 Valid RCPT command must precede %s\r\n", FALSE,
5139 smtp_names[smtp_connection_had[smtp_ch_index-1]]);
5141 done = synprot_error(L_smtp_protocol_error, 503, NULL,
5142 smtp_connection_had[smtp_ch_index-1] == SCH_DATA
5143 ? US"valid RCPT command must precede DATA"
5144 : US"valid RCPT command must precede BDAT");
5146 if (chunking_state > CHUNKING_OFFERED)
5151 if (toomany && recipients_max_reject)
5153 sender_address = NULL; /* This will allow a new MAIL without RSET */
5154 sender_address_unrewritten = NULL;
5155 smtp_printf("554 Too many recipients\r\n", FALSE);
5159 if (chunking_state > CHUNKING_OFFERED)
5160 rc = OK; /* No predata ACL or go-ahead output for BDAT */
5163 /* If there is an ACL, re-check the synchronization afterwards, since the
5164 ACL may have delayed. To handle cutthrough delivery enforce a dummy call
5165 to get the DATA command sent. */
5167 if (acl_smtp_predata == NULL && cutthrough.fd < 0)
5171 uschar * acl = acl_smtp_predata ? acl_smtp_predata : US"accept";
5172 enable_dollar_recipients = TRUE;
5173 rc = acl_check(ACL_WHERE_PREDATA, NULL, acl, &user_msg,
5175 enable_dollar_recipients = FALSE;
5176 if (rc == OK && !check_sync())
5180 { /* Either the ACL failed the address, or it was deferred. */
5181 done = smtp_handle_acl_fail(ACL_WHERE_PREDATA, rc, user_msg, log_msg);
5187 smtp_user_msg(US"354", user_msg);
5190 "354 Enter message, ending with \".\" on a line by itself\r\n", FALSE);
5194 if (smtp_in) /* all ACKs needed to ramp window up for bulk data */
5195 (void) setsockopt(fileno(smtp_in), IPPROTO_TCP, TCP_QUICKACK,
5196 US &on, sizeof(on));
5199 message_ended = END_NOTENDED; /* Indicate in middle of data */
5210 if (!(address = parse_extract_address(smtp_cmd_data, &errmess,
5211 &start, &end, &recipient_domain, FALSE)))
5213 smtp_printf("501 %s\r\n", FALSE, errmess);
5217 if (!recipient_domain)
5218 if (!(recipient_domain = qualify_recipient(&address, smtp_cmd_data,
5222 if ((rc = acl_check(ACL_WHERE_VRFY, address, acl_smtp_vrfy,
5223 &user_msg, &log_msg)) != OK)
5224 done = smtp_handle_acl_fail(ACL_WHERE_VRFY, rc, user_msg, log_msg);
5228 address_item * addr = deliver_make_addr(address, FALSE);
5230 switch(verify_address(addr, NULL, vopt_is_recipient | vopt_qualify, -1,
5231 -1, -1, NULL, NULL, NULL))
5234 s = string_sprintf("250 <%s> is deliverable", address);
5238 s = (addr->user_message != NULL)?
5239 string_sprintf("451 <%s> %s", address, addr->user_message) :
5240 string_sprintf("451 Cannot resolve <%s> at this time", address);
5244 s = (addr->user_message != NULL)?
5245 string_sprintf("550 <%s> %s", address, addr->user_message) :
5246 string_sprintf("550 <%s> is not deliverable", address);
5247 log_write(0, LOG_MAIN, "VRFY failed for %s %s",
5248 smtp_cmd_argument, host_and_ident(TRUE));
5252 smtp_printf("%s\r\n", FALSE, s);
5260 rc = acl_check(ACL_WHERE_EXPN, NULL, acl_smtp_expn, &user_msg, &log_msg);
5262 done = smtp_handle_acl_fail(ACL_WHERE_EXPN, rc, user_msg, log_msg);
5265 BOOL save_log_testing_mode = log_testing_mode;
5266 address_test_mode = log_testing_mode = TRUE;
5267 (void) verify_address(deliver_make_addr(smtp_cmd_data, FALSE),
5268 smtp_out, vopt_is_recipient | vopt_qualify | vopt_expn, -1, -1, -1,
5270 address_test_mode = FALSE;
5271 log_testing_mode = save_log_testing_mode; /* true for -bh */
5280 if (!tls_advertised)
5282 done = synprot_error(L_smtp_protocol_error, 503, NULL,
5283 US"STARTTLS command used when not advertised");
5287 /* Apply an ACL check if one is defined */
5289 if ( acl_smtp_starttls
5290 && (rc = acl_check(ACL_WHERE_STARTTLS, NULL, acl_smtp_starttls,
5291 &user_msg, &log_msg)) != OK
5294 done = smtp_handle_acl_fail(ACL_WHERE_STARTTLS, rc, user_msg, log_msg);
5298 /* RFC 2487 is not clear on when this command may be sent, though it
5299 does state that all information previously obtained from the client
5300 must be discarded if a TLS session is started. It seems reasonable to
5301 do an implied RSET when STARTTLS is received. */
5303 incomplete_transaction_log(US"STARTTLS");
5304 cancel_cutthrough_connection(TRUE, US"STARTTLS received");
5305 smtp_reset(reset_point);
5307 cmd_list[CMD_LIST_STARTTLS].is_mail_cmd = FALSE;
5309 /* There's an attack where more data is read in past the STARTTLS command
5310 before TLS is negotiated, then assumed to be part of the secure session
5311 when used afterwards; we use segregated input buffers, so are not
5312 vulnerable, but we want to note when it happens and, for sheer paranoia,
5313 ensure that the buffer is "wiped".
5314 Pipelining sync checks will normally have protected us too, unless disabled
5315 by configuration. */
5317 if (receive_smtp_buffered())
5320 debug_printf("Non-empty input buffer after STARTTLS; naive attack?\n");
5321 if (tls_in.active < 0)
5322 smtp_inend = smtp_inptr = smtp_inbuffer;
5323 /* and if TLS is already active, tls_server_start() should fail */
5326 /* There is nothing we value in the input buffer and if TLS is successfully
5327 negotiated, we won't use this buffer again; if TLS fails, we'll just read
5328 fresh content into it. The buffer contains arbitrary content from an
5329 untrusted remote source; eg: NOOP <shellcode>\r\nSTARTTLS\r\n
5330 It seems safest to just wipe away the content rather than leave it as a
5331 target to jump to. */
5333 memset(smtp_inbuffer, 0, IN_BUFFER_SIZE);
5335 /* Attempt to start up a TLS session, and if successful, discard all
5336 knowledge that was obtained previously. At least, that's what the RFC says,
5337 and that's what happens by default. However, in order to work round YAEB,
5338 there is an option to remember the esmtp state. Sigh.
5340 We must allow for an extra EHLO command and an extra AUTH command after
5341 STARTTLS that don't add to the nonmail command count. */
5344 if ((rc = tls_server_start(tls_require_ciphers, &s)) == OK)
5346 if (!tls_remember_esmtp)
5347 helo_seen = esmtp = auth_advertised = pipelining_advertised = FALSE;
5348 cmd_list[CMD_LIST_EHLO].is_mail_cmd = TRUE;
5349 cmd_list[CMD_LIST_AUTH].is_mail_cmd = TRUE;
5350 cmd_list[CMD_LIST_TLS_AUTH].is_mail_cmd = TRUE;
5351 if (sender_helo_name)
5353 store_free(sender_helo_name);
5354 sender_helo_name = NULL;
5355 host_build_sender_fullhost(); /* Rebuild */
5356 set_process_info("handling incoming TLS connection from %s",
5357 host_and_ident(FALSE));
5360 (sender_host_address ? protocols : protocols_local)
5362 ? pextend + (sender_host_authenticated ? pauthed : 0)
5364 + (tls_in.active >= 0 ? pcrpted : 0)
5367 sender_host_auth_pubname = sender_host_authenticated = NULL;
5368 authenticated_id = NULL;
5369 sync_cmd_limit = NON_SYNC_CMD_NON_PIPELINING;
5370 DEBUG(D_tls) debug_printf("TLS active\n");
5371 break; /* Successful STARTTLS */
5374 (void) smtp_log_tls_fail(s);
5376 /* Some local configuration problem was discovered before actually trying
5377 to do a TLS handshake; give a temporary error. */
5381 smtp_printf("454 TLS currently unavailable\r\n", FALSE);
5385 /* Hard failure. Reject everything except QUIT or closed connection. One
5386 cause for failure is a nested STARTTLS, in which case tls_in.active remains
5387 set, but we must still reject all incoming commands. */
5389 DEBUG(D_tls) debug_printf("TLS failed to start\n");
5390 while (done <= 0) switch(smtp_read_command(FALSE, GETC_BUFFER_UNLIMITED))
5393 log_write(L_smtp_connection, LOG_MAIN, "%s closed by EOF",
5394 smtp_get_connection_info());
5395 smtp_notquit_exit(US"tls-failed", NULL, NULL);
5399 /* It is perhaps arguable as to which exit ACL should be called here,
5400 but as it is probably a situation that almost never arises, it
5401 probably doesn't matter. We choose to call the real QUIT ACL, which in
5402 some sense is perhaps "right". */
5407 && ((rc = acl_check(ACL_WHERE_QUIT, NULL, acl_smtp_quit, &user_msg,
5408 &log_msg)) == ERROR))
5409 log_write(0, LOG_MAIN|LOG_PANIC, "ACL for QUIT returned ERROR: %s",
5412 smtp_respond(US"221", 3, TRUE, user_msg);
5414 smtp_printf("221 %s closing connection\r\n", FALSE, smtp_active_hostname);
5415 log_write(L_smtp_connection, LOG_MAIN, "%s closed by QUIT",
5416 smtp_get_connection_info());
5421 smtp_printf("554 Security failure\r\n", FALSE);
5424 tls_close(TRUE, TLS_SHUTDOWN_NOWAIT);
5429 /* The ACL for QUIT is provided for gathering statistical information or
5430 similar; it does not affect the response code, but it can supply a custom
5434 smtp_quit_handler(&user_msg, &log_msg);
5440 smtp_rset_handler();
5441 cancel_cutthrough_connection(TRUE, US"RSET received");
5442 smtp_reset(reset_point);
5449 smtp_printf("250 OK\r\n", FALSE);
5453 /* Show ETRN/EXPN/VRFY if there's an ACL for checking hosts; if actually
5454 used, a check will be done for permitted hosts. Show STARTTLS only if not
5455 already in a TLS session and if it would be advertised in the EHLO
5460 smtp_printf("214-Commands supported:\r\n", TRUE);
5464 Ustrcat(buffer, " AUTH");
5466 if (tls_in.active < 0 &&
5467 verify_check_host(&tls_advertise_hosts) != FAIL)
5468 Ustrcat(buffer, " STARTTLS");
5470 Ustrcat(buffer, " HELO EHLO MAIL RCPT DATA BDAT");
5471 Ustrcat(buffer, " NOOP QUIT RSET HELP");
5472 if (acl_smtp_etrn != NULL) Ustrcat(buffer, " ETRN");
5473 if (acl_smtp_expn != NULL) Ustrcat(buffer, " EXPN");
5474 if (acl_smtp_vrfy != NULL) Ustrcat(buffer, " VRFY");
5475 smtp_printf("214%s\r\n", FALSE, buffer);
5481 incomplete_transaction_log(US"connection lost");
5482 smtp_notquit_exit(US"connection-lost", US"421",
5483 US"%s lost input connection", smtp_active_hostname);
5485 /* Don't log by default unless in the middle of a message, as some mailers
5486 just drop the call rather than sending QUIT, and it clutters up the logs.
5489 if (sender_address || recipients_count > 0)
5490 log_write(L_lost_incoming_connection, LOG_MAIN,
5491 "unexpected %s while reading SMTP command from %s%s%s D=%s",
5492 sender_host_unknown ? "EOF" : "disconnection",
5493 tcp_in_fastopen && !tcp_in_fastopen_logged ? US"TFO " : US"",
5494 host_and_ident(FALSE), smtp_read_error,
5495 string_timesince(&smtp_connection_start)
5499 log_write(L_smtp_connection, LOG_MAIN, "%s %slost%s D=%s",
5500 smtp_get_connection_info(),
5501 tcp_in_fastopen && !tcp_in_fastopen_logged ? US"TFO " : US"",
5503 string_timesince(&smtp_connection_start)
5514 done = synprot_error(L_smtp_protocol_error, 503, NULL,
5515 US"ETRN is not permitted inside a transaction");
5519 log_write(L_etrn, LOG_MAIN, "ETRN %s received from %s", smtp_cmd_argument,
5520 host_and_ident(FALSE));
5522 if ((rc = acl_check(ACL_WHERE_ETRN, NULL, acl_smtp_etrn,
5523 &user_msg, &log_msg)) != OK)
5525 done = smtp_handle_acl_fail(ACL_WHERE_ETRN, rc, user_msg, log_msg);
5529 /* Compute the serialization key for this command. */
5531 etrn_serialize_key = string_sprintf("etrn-%s\n", smtp_cmd_data);
5533 /* If a command has been specified for running as a result of ETRN, we
5534 permit any argument to ETRN. If not, only the # standard form is permitted,
5535 since that is strictly the only kind of ETRN that can be implemented
5536 according to the RFC. */
5538 if (smtp_etrn_command)
5542 etrn_command = smtp_etrn_command;
5543 deliver_domain = smtp_cmd_data;
5544 rc = transport_set_up_command(&argv, smtp_etrn_command, TRUE, 0, NULL,
5545 US"ETRN processing", &error);
5546 deliver_domain = NULL;
5549 log_write(0, LOG_MAIN|LOG_PANIC, "failed to set up ETRN command: %s",
5551 smtp_printf("458 Internal failure\r\n", FALSE);
5556 /* Else set up to call Exim with the -R option. */
5560 if (*smtp_cmd_data++ != '#')
5562 done = synprot_error(L_smtp_syntax_error, 501, NULL,
5563 US"argument must begin with #");
5566 etrn_command = US"exim -R";
5567 argv = CUSS child_exec_exim(CEE_RETURN_ARGV, TRUE, NULL, TRUE,
5568 *queue_name ? 4 : 2,
5569 US"-R", smtp_cmd_data,
5570 US"-MCG", queue_name);
5573 /* If we are host-testing, don't actually do anything. */
5579 debug_printf("ETRN command is: %s\n", etrn_command);
5580 debug_printf("ETRN command execution skipped\n");
5582 if (user_msg == NULL) smtp_printf("250 OK\r\n", FALSE);
5583 else smtp_user_msg(US"250", user_msg);
5588 /* If ETRN queue runs are to be serialized, check the database to
5589 ensure one isn't already running. */
5591 if (smtp_etrn_serialize && !enq_start(etrn_serialize_key, 1))
5593 smtp_printf("458 Already processing %s\r\n", FALSE, smtp_cmd_data);
5597 /* Fork a child process and run the command. We don't want to have to
5598 wait for the process at any point, so set SIGCHLD to SIG_IGN before
5599 forking. It should be set that way anyway for external incoming SMTP,
5600 but we save and restore to be tidy. If serialization is required, we
5601 actually run the command in yet another process, so we can wait for it
5602 to complete and then remove the serialization lock. */
5604 oldsignal = signal(SIGCHLD, SIG_IGN);
5606 if ((pid = fork()) == 0)
5608 smtp_input = FALSE; /* This process is not associated with the */
5609 (void)fclose(smtp_in); /* SMTP call any more. */
5610 (void)fclose(smtp_out);
5612 signal(SIGCHLD, SIG_DFL); /* Want to catch child */
5614 /* If not serializing, do the exec right away. Otherwise, fork down
5615 into another process. */
5617 if (!smtp_etrn_serialize || (pid = fork()) == 0)
5619 DEBUG(D_exec) debug_print_argv(argv);
5620 exim_nullstd(); /* Ensure std{in,out,err} exist */
5621 execv(CS argv[0], (char *const *)argv);
5622 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "exec of \"%s\" (ETRN) failed: %s",
5623 etrn_command, strerror(errno));
5624 _exit(EXIT_FAILURE); /* paranoia */
5627 /* Obey this if smtp_serialize and the 2nd fork yielded non-zero. That
5628 is, we are in the first subprocess, after forking again. All we can do
5629 for a failing fork is to log it. Otherwise, wait for the 2nd process to
5630 complete, before removing the serialization. */
5633 log_write(0, LOG_MAIN|LOG_PANIC, "2nd fork for serialized ETRN "
5634 "failed: %s", strerror(errno));
5638 DEBUG(D_any) debug_printf("waiting for serialized ETRN process %d\n",
5640 (void)wait(&status);
5641 DEBUG(D_any) debug_printf("serialized ETRN process %d ended\n",
5645 enq_end(etrn_serialize_key);
5646 _exit(EXIT_SUCCESS);
5649 /* Back in the top level SMTP process. Check that we started a subprocess
5650 and restore the signal state. */
5654 log_write(0, LOG_MAIN|LOG_PANIC, "fork of process for ETRN failed: %s",
5656 smtp_printf("458 Unable to fork process\r\n", FALSE);
5657 if (smtp_etrn_serialize) enq_end(etrn_serialize_key);
5661 if (user_msg == NULL) smtp_printf("250 OK\r\n", FALSE);
5662 else smtp_user_msg(US"250", user_msg);
5665 signal(SIGCHLD, oldsignal);
5670 done = synprot_error(L_smtp_syntax_error, 501, NULL,
5671 US"unexpected argument data");
5675 /* This currently happens only for NULLs, but could be extended. */
5678 done = synprot_error(L_smtp_syntax_error, 0, NULL, /* Just logs */
5679 US"NUL character(s) present (shown as '?')");
5680 smtp_printf("501 NUL characters are not allowed in SMTP commands\r\n", FALSE);
5686 if (smtp_inend >= smtp_inbuffer + IN_BUFFER_SIZE)
5687 smtp_inend = smtp_inbuffer + IN_BUFFER_SIZE - 1;
5688 c = smtp_inend - smtp_inptr;
5689 if (c > 150) c = 150; /* limit logged amount */
5691 incomplete_transaction_log(US"sync failure");
5692 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP protocol synchronization error "
5693 "(next input sent too soon: pipelining was%s advertised): "
5694 "rejected \"%s\" %s next input=\"%s\"",
5695 pipelining_advertised? "" : " not",
5696 smtp_cmd_buffer, host_and_ident(TRUE),
5697 string_printing(smtp_inptr));
5698 smtp_notquit_exit(US"synchronization-error", US"554",
5699 US"SMTP synchronization error");
5700 done = 1; /* Pretend eof - drops connection */
5704 case TOO_MANY_NONMAIL_CMD:
5705 s = smtp_cmd_buffer;
5706 while (*s != 0 && !isspace(*s)) s++;
5707 incomplete_transaction_log(US"too many non-mail commands");
5708 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
5709 "nonmail commands (last was \"%.*s\")", host_and_ident(FALSE),
5710 (int)(s - smtp_cmd_buffer), smtp_cmd_buffer);
5711 smtp_notquit_exit(US"bad-commands", US"554", US"Too many nonmail commands");
5712 done = 1; /* Pretend eof - drops connection */
5715 #ifdef SUPPORT_PROXY
5716 case PROXY_FAIL_IGNORE_CMD:
5717 smtp_printf("503 Command refused, required Proxy negotiation failed\r\n", FALSE);
5722 if (unknown_command_count++ >= smtp_max_unknown_commands)
5724 log_write(L_smtp_syntax_error, LOG_MAIN,
5725 "SMTP syntax error in \"%s\" %s %s",
5726 string_printing(smtp_cmd_buffer), host_and_ident(TRUE),
5727 US"unrecognized command");
5728 incomplete_transaction_log(US"unrecognized command");
5729 smtp_notquit_exit(US"bad-commands", US"500",
5730 US"Too many unrecognized commands");
5732 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
5733 "unrecognized commands (last was \"%s\")", host_and_ident(FALSE),
5734 string_printing(smtp_cmd_buffer));
5737 done = synprot_error(L_smtp_syntax_error, 500, NULL,
5738 US"unrecognized command");
5742 /* This label is used by goto's inside loops that want to break out to
5743 the end of the command-processing loop. */
5746 last_was_rej_mail = was_rej_mail; /* Remember some last commands for */
5747 last_was_rcpt = was_rcpt; /* protocol error handling */
5751 return done - 2; /* Convert yield values */
5757 authres_smtpauth(gstring * g)
5759 if (!sender_host_authenticated)
5762 g = string_append(g, 2, US";\n\tauth=pass (", sender_host_auth_pubname);
5764 if (Ustrcmp(sender_host_auth_pubname, "tls") != 0)
5765 g = string_append(g, 2, US") smtp.auth=", authenticated_id);
5766 else if (authenticated_id)
5767 g = string_append(g, 2, US") x509.auth=", authenticated_id);
5769 g = string_catn(g, US") reason=x509.auth", 17);
5771 if (authenticated_sender)
5772 g = string_append(g, 2, US" smtp.mailfrom=", authenticated_sender);
5780 /* End of smtp_in.c */