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 =
1999 dkim_signing_domain = dkim_signing_selector = NULL;
2000 dkim_cur_signer = dkim_signers = dkim_signing_domain = dkim_signing_selector = NULL;
2001 dkim_disable_verify = dkim_collect_input = FALSE;
2002 dkim_verify_overall = dkim_verify_status = dkim_verify_reason = NULL;
2003 dkim_key_length = 0;
2004 dkim_verify_signers = US"$dkim_signers";
2008 deliver_host = deliver_host_address = NULL; /* Can be set by ACL */
2009 #ifndef DISABLE_PRDR
2010 prdr_requested = FALSE;
2013 spf_header_comment = spf_received = spf_result = spf_smtp_comment = NULL;
2014 spf_result_guessed = FALSE;
2016 #ifdef EXPERIMENTAL_DMARC
2017 dmarc_has_been_checked = dmarc_disable_verify = dmarc_enable_forensic = FALSE;
2018 dmarc_domain_policy = dmarc_status = dmarc_status_text = dmarc_used_domain = NULL;
2020 #ifdef EXPERIMENTAL_ARC
2021 arc_state = arc_state_reason = NULL;
2024 message_smtputf8 = FALSE;
2026 body_linecount = body_zerocount = 0;
2028 sender_rate = sender_rate_limit = sender_rate_period = NULL;
2029 ratelimiters_mail = NULL; /* Updated by ratelimit ACL condition */
2030 /* Note that ratelimiters_conn persists across resets. */
2032 /* Reset message ACL variables */
2036 /* The message body variables use malloc store. They may be set if this is
2037 not the first message in an SMTP session and the previous message caused them
2038 to be referenced in an ACL. */
2042 store_free(message_body);
2043 message_body = NULL;
2046 if (message_body_end)
2048 store_free(message_body_end);
2049 message_body_end = NULL;
2052 /* Warning log messages are also saved in malloc store. They are saved to avoid
2053 repetition in the same message, but it seems right to repeat them for different
2056 while (acl_warn_logged)
2058 string_item *this = acl_warn_logged;
2059 acl_warn_logged = acl_warn_logged->next;
2062 store_reset(reset_point);
2069 /*************************************************
2070 * Initialize for incoming batched SMTP message *
2071 *************************************************/
2073 /* This function is called from smtp_setup_msg() in the case when
2074 smtp_batched_input is true. This happens when -bS is used to pass a whole batch
2075 of messages in one file with SMTP commands between them. All errors must be
2076 reported by sending a message, and only MAIL FROM, RCPT TO, and DATA are
2077 relevant. After an error on a sender, or an invalid recipient, the remainder
2078 of the message is skipped. The value of received_protocol is already set.
2081 Returns: > 0 message successfully started (reached DATA)
2082 = 0 QUIT read or end of file reached
2083 < 0 should not occur
2087 smtp_setup_batch_msg(void)
2090 void *reset_point = store_get(0);
2092 /* Save the line count at the start of each transaction - single commands
2093 like HELO and RSET count as whole transactions. */
2095 bsmtp_transaction_linecount = receive_linecount;
2097 if ((receive_feof)()) return 0; /* Treat EOF as QUIT */
2099 cancel_cutthrough_connection(TRUE, US"smtp_setup_batch_msg");
2100 smtp_reset(reset_point); /* Reset for start of message */
2102 /* Deal with SMTP commands. This loop is exited by setting done to a POSITIVE
2103 value. The values are 2 larger than the required yield of the function. */
2108 uschar *recipient = NULL;
2109 int start, end, sender_domain, recipient_domain;
2111 switch(smtp_read_command(FALSE, GETC_BUFFER_UNLIMITED))
2113 /* The HELO/EHLO commands set sender_address_helo if they have
2114 valid data; otherwise they are ignored, except that they do
2115 a reset of the state. */
2120 check_helo(smtp_cmd_data);
2124 cancel_cutthrough_connection(TRUE, US"RSET received");
2125 smtp_reset(reset_point);
2126 bsmtp_transaction_linecount = receive_linecount;
2130 /* The MAIL FROM command requires an address as an operand. All we
2131 do here is to parse it for syntactic correctness. The form "<>" is
2132 a special case which converts into an empty string. The start/end
2133 pointers in the original are not used further for this address, as
2134 it is the canonical extracted address which is all that is kept. */
2137 smtp_mailcmd_count++; /* Count for no-mail log */
2138 if (sender_address != NULL)
2139 /* The function moan_smtp_batch() does not return. */
2140 moan_smtp_batch(smtp_cmd_buffer, "503 Sender already given");
2142 if (smtp_cmd_data[0] == 0)
2143 /* The function moan_smtp_batch() does not return. */
2144 moan_smtp_batch(smtp_cmd_buffer, "501 MAIL FROM must have an address operand");
2146 /* Reset to start of message */
2148 cancel_cutthrough_connection(TRUE, US"MAIL received");
2149 smtp_reset(reset_point);
2151 /* Apply SMTP rewrite */
2153 raw_sender = ((rewrite_existflags & rewrite_smtp) != 0)?
2154 rewrite_one(smtp_cmd_data, rewrite_smtp|rewrite_smtp_sender, NULL, FALSE,
2155 US"", global_rewrite_rules) : smtp_cmd_data;
2157 /* Extract the address; the TRUE flag allows <> as valid */
2160 parse_extract_address(raw_sender, &errmess, &start, &end, &sender_domain,
2164 /* The function moan_smtp_batch() does not return. */
2165 moan_smtp_batch(smtp_cmd_buffer, "501 %s", errmess);
2167 sender_address = string_copy(raw_sender);
2169 /* Qualify unqualified sender addresses if permitted to do so. */
2172 && sender_address[0] != 0 && sender_address[0] != '@')
2173 if (allow_unqualified_sender)
2175 sender_address = rewrite_address_qualify(sender_address, FALSE);
2176 DEBUG(D_receive) debug_printf("unqualified address %s accepted "
2177 "and rewritten\n", raw_sender);
2179 /* The function moan_smtp_batch() does not return. */
2181 moan_smtp_batch(smtp_cmd_buffer, "501 sender address must contain "
2186 /* The RCPT TO command requires an address as an operand. All we do
2187 here is to parse it for syntactic correctness. There may be any number
2188 of RCPT TO commands, specifying multiple senders. We build them all into
2189 a data structure that is in argc/argv format. The start/end values
2190 given by parse_extract_address are not used, as we keep only the
2191 extracted address. */
2194 if (!sender_address)
2195 /* The function moan_smtp_batch() does not return. */
2196 moan_smtp_batch(smtp_cmd_buffer, "503 No sender yet given");
2198 if (smtp_cmd_data[0] == 0)
2199 /* The function moan_smtp_batch() does not return. */
2200 moan_smtp_batch(smtp_cmd_buffer,
2201 "501 RCPT TO must have an address operand");
2203 /* Check maximum number allowed */
2205 if (recipients_max > 0 && recipients_count + 1 > recipients_max)
2206 /* The function moan_smtp_batch() does not return. */
2207 moan_smtp_batch(smtp_cmd_buffer, "%s too many recipients",
2208 recipients_max_reject? "552": "452");
2210 /* Apply SMTP rewrite, then extract address. Don't allow "<>" as a
2211 recipient address */
2213 recipient = rewrite_existflags & rewrite_smtp
2214 ? rewrite_one(smtp_cmd_data, rewrite_smtp, NULL, FALSE, US"",
2215 global_rewrite_rules)
2218 recipient = parse_extract_address(recipient, &errmess, &start, &end,
2219 &recipient_domain, FALSE);
2222 /* The function moan_smtp_batch() does not return. */
2223 moan_smtp_batch(smtp_cmd_buffer, "501 %s", errmess);
2225 /* If the recipient address is unqualified, qualify it if permitted. Then
2226 add it to the list of recipients. */
2228 if (!recipient_domain)
2229 if (allow_unqualified_recipient)
2231 DEBUG(D_receive) debug_printf("unqualified address %s accepted\n",
2233 recipient = rewrite_address_qualify(recipient, TRUE);
2235 /* The function moan_smtp_batch() does not return. */
2237 moan_smtp_batch(smtp_cmd_buffer,
2238 "501 recipient address must contain a domain");
2240 receive_add_recipient(recipient, -1);
2244 /* The DATA command is legal only if it follows successful MAIL FROM
2245 and RCPT TO commands. This function is complete when a valid DATA
2246 command is encountered. */
2249 if (!sender_address || recipients_count <= 0)
2250 /* The function moan_smtp_batch() does not return. */
2251 if (!sender_address)
2252 moan_smtp_batch(smtp_cmd_buffer,
2253 "503 MAIL FROM:<sender> command must precede DATA");
2255 moan_smtp_batch(smtp_cmd_buffer,
2256 "503 RCPT TO:<recipient> must precede DATA");
2259 done = 3; /* DATA successfully achieved */
2260 message_ended = END_NOTENDED; /* Indicate in middle of message */
2265 /* The VRFY, EXPN, HELP, ETRN, and NOOP commands are ignored. */
2272 bsmtp_transaction_linecount = receive_linecount;
2283 /* The function moan_smtp_batch() does not return. */
2284 moan_smtp_batch(smtp_cmd_buffer, "501 Unexpected argument data");
2289 /* The function moan_smtp_batch() does not return. */
2290 moan_smtp_batch(smtp_cmd_buffer, "501 Unexpected NULL in SMTP command");
2295 /* The function moan_smtp_batch() does not return. */
2296 moan_smtp_batch(smtp_cmd_buffer, "500 Command unrecognized");
2301 return done - 2; /* Convert yield values */
2308 smtp_log_tls_fail(uschar * errstr)
2310 uschar * conn_info = smtp_get_connection_info();
2312 if (Ustrncmp(conn_info, US"SMTP ", 5) == 0) conn_info += 5;
2313 /* I'd like to get separated H= here, but too hard for now */
2315 log_write(0, LOG_MAIN, "TLS error on %s %s", conn_info, errstr);
2327 struct tcp_info tinfo;
2328 socklen_t len = sizeof(tinfo);
2330 if ( getsockopt(fileno(smtp_out), IPPROTO_TCP, TCP_INFO, &tinfo, &len) == 0
2331 && tinfo.tcpi_state == TCP_SYN_RECV
2334 DEBUG(D_receive) debug_printf("TCP_FASTOPEN mode connection (state TCP_SYN_RECV)\n");
2335 tcp_in_fastopen = TRUE;
2342 /*************************************************
2343 * Start an SMTP session *
2344 *************************************************/
2346 /* This function is called at the start of an SMTP session. Thereafter,
2347 smtp_setup_msg() is called to initiate each separate message. This
2348 function does host-specific testing, and outputs the banner line.
2351 Returns: FALSE if the session can not continue; something has
2352 gone wrong, or the connection to the host is blocked
2356 smtp_start_session(void)
2359 uschar *user_msg, *log_msg;
2364 gettimeofday(&smtp_connection_start, NULL);
2365 for (smtp_ch_index = 0; smtp_ch_index < SMTP_HBUFF_SIZE; smtp_ch_index++)
2366 smtp_connection_had[smtp_ch_index] = SCH_NONE;
2369 /* Default values for certain variables */
2371 helo_seen = esmtp = helo_accept_junk = FALSE;
2372 smtp_mailcmd_count = 0;
2373 count_nonmail = TRUE_UNSET;
2374 synprot_error_count = unknown_command_count = nonmail_command_count = 0;
2375 smtp_delay_mail = smtp_rlm_base;
2376 auth_advertised = FALSE;
2377 pipelining_advertised = FALSE;
2378 pipelining_enable = TRUE;
2379 sync_cmd_limit = NON_SYNC_CMD_NON_PIPELINING;
2380 smtp_exit_function_called = FALSE; /* For avoiding loop in not-quit exit */
2382 /* If receiving by -bs from a trusted user, or testing with -bh, we allow
2383 authentication settings from -oMaa to remain in force. */
2385 if (!host_checking && !sender_host_notsocket)
2386 sender_host_auth_pubname = sender_host_authenticated = NULL;
2387 authenticated_by = NULL;
2390 tls_in.cipher = tls_in.peerdn = NULL;
2391 tls_in.ourcert = tls_in.peercert = NULL;
2393 tls_in.ocsp = OCSP_NOT_REQ;
2394 tls_advertised = FALSE;
2396 dsn_advertised = FALSE;
2398 smtputf8_advertised = FALSE;
2401 /* Reset ACL connection variables */
2405 /* Allow for trailing 0 in the command and data buffers. */
2407 if (!(smtp_cmd_buffer = US malloc(2*SMTP_CMD_BUFFER_SIZE + 2)))
2408 log_write(0, LOG_MAIN|LOG_PANIC_DIE,
2409 "malloc() failed for SMTP command buffer");
2411 smtp_cmd_buffer[0] = 0;
2412 smtp_data_buffer = smtp_cmd_buffer + SMTP_CMD_BUFFER_SIZE + 1;
2414 /* For batched input, the protocol setting can be overridden from the
2415 command line by a trusted caller. */
2417 if (smtp_batched_input)
2419 if (!received_protocol) received_protocol = US"local-bsmtp";
2422 /* For non-batched SMTP input, the protocol setting is forced here. It will be
2423 reset later if any of EHLO/AUTH/STARTTLS are received. */
2427 (sender_host_address ? protocols : protocols_local) [pnormal];
2429 /* Set up the buffer for inputting using direct read() calls, and arrange to
2430 call the local functions instead of the standard C ones. Place a NUL at the
2431 end of the buffer to safety-stop C-string reads from it. */
2433 if (!(smtp_inbuffer = US malloc(IN_BUFFER_SIZE)))
2434 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "malloc() failed for SMTP input buffer");
2435 smtp_inbuffer[IN_BUFFER_SIZE-1] = '\0';
2437 receive_getc = smtp_getc;
2438 receive_getbuf = smtp_getbuf;
2439 receive_get_cache = smtp_get_cache;
2440 receive_ungetc = smtp_ungetc;
2441 receive_feof = smtp_feof;
2442 receive_ferror = smtp_ferror;
2443 receive_smtp_buffered = smtp_buffered;
2444 smtp_inptr = smtp_inend = smtp_inbuffer;
2445 smtp_had_eof = smtp_had_error = 0;
2447 /* Set up the message size limit; this may be host-specific */
2449 thismessage_size_limit = expand_string_integer(message_size_limit, TRUE);
2450 if (expand_string_message)
2452 if (thismessage_size_limit == -1)
2453 log_write(0, LOG_MAIN|LOG_PANIC, "unable to expand message_size_limit: "
2454 "%s", expand_string_message);
2456 log_write(0, LOG_MAIN|LOG_PANIC, "invalid message_size_limit: "
2457 "%s", expand_string_message);
2458 smtp_closedown(US"Temporary local problem - please try later");
2462 /* When a message is input locally via the -bs or -bS options, sender_host_
2463 unknown is set unless -oMa was used to force an IP address, in which case it
2464 is checked like a real remote connection. When -bs is used from inetd, this
2465 flag is not set, causing the sending host to be checked. The code that deals
2466 with IP source routing (if configured) is never required for -bs or -bS and
2467 the flag sender_host_notsocket is used to suppress it.
2469 If smtp_accept_max and smtp_accept_reserve are set, keep some connections in
2470 reserve for certain hosts and/or networks. */
2472 if (!sender_host_unknown)
2475 BOOL reserved_host = FALSE;
2477 /* Look up IP options (source routing info) on the socket if this is not an
2478 -oMa "host", and if any are found, log them and drop the connection.
2480 Linux (and others now, see below) is different to everyone else, so there
2481 has to be some conditional compilation here. Versions of Linux before 2.1.15
2482 used a structure whose name was "options". Somebody finally realized that
2483 this name was silly, and it got changed to "ip_options". I use the
2484 newer name here, but there is a fudge in the script that sets up os.h
2485 to define a macro in older Linux systems.
2487 Sigh. Linux is a fast-moving target. Another generation of Linux uses
2488 glibc 2, which has chosen ip_opts for the structure name. This is now
2489 really a glibc thing rather than a Linux thing, so the condition name
2490 has been changed to reflect this. It is relevant also to GNU/Hurd.
2492 Mac OS 10.x (Darwin) is like the later glibc versions, but without the
2493 setting of the __GLIBC__ macro, so we can't detect it automatically. There's
2494 a special macro defined in the os.h file.
2496 Some DGUX versions on older hardware appear not to support IP options at
2497 all, so there is now a general macro which can be set to cut out this
2500 How to do this properly in IPv6 is not yet known. */
2502 #if !HAVE_IPV6 && !defined(NO_IP_OPTIONS)
2504 #ifdef GLIBC_IP_OPTIONS
2505 #if (!defined __GLIBC__) || (__GLIBC__ < 2)
2510 #elif defined DARWIN_IP_OPTIONS
2516 if (!host_checking && !sender_host_notsocket)
2519 EXIM_SOCKLEN_T optlen = sizeof(struct ip_options) + MAX_IPOPTLEN;
2520 struct ip_options *ipopt = store_get(optlen);
2522 struct ip_opts ipoptblock;
2523 struct ip_opts *ipopt = &ipoptblock;
2524 EXIM_SOCKLEN_T optlen = sizeof(ipoptblock);
2526 struct ipoption ipoptblock;
2527 struct ipoption *ipopt = &ipoptblock;
2528 EXIM_SOCKLEN_T optlen = sizeof(ipoptblock);
2531 /* Occasional genuine failures of getsockopt() have been seen - for
2532 example, "reset by peer". Therefore, just log and give up on this
2533 call, unless the error is ENOPROTOOPT. This error is given by systems
2534 that have the interfaces but not the mechanism - e.g. GNU/Hurd at the time
2535 of writing. So for that error, carry on - we just can't do an IP options
2538 DEBUG(D_receive) debug_printf("checking for IP options\n");
2540 if (getsockopt(fileno(smtp_out), IPPROTO_IP, IP_OPTIONS, US (ipopt),
2543 if (errno != ENOPROTOOPT)
2545 log_write(0, LOG_MAIN, "getsockopt() failed from %s: %s",
2546 host_and_ident(FALSE), strerror(errno));
2547 smtp_printf("451 SMTP service not available\r\n", FALSE);
2552 /* Deal with any IP options that are set. On the systems I have looked at,
2553 the value of MAX_IPOPTLEN has been 40, meaning that there should never be
2554 more logging data than will fit in big_buffer. Nevertheless, after somebody
2555 questioned this code, I've added in some paranoid checking. */
2557 else if (optlen > 0)
2559 uschar *p = big_buffer;
2560 uschar *pend = big_buffer + big_buffer_size;
2561 uschar *opt, *adptr;
2563 struct in_addr addr;
2566 uschar *optstart = US (ipopt->__data);
2568 uschar *optstart = US (ipopt->ip_opts);
2570 uschar *optstart = US (ipopt->ipopt_list);
2573 DEBUG(D_receive) debug_printf("IP options exist\n");
2575 Ustrcpy(p, "IP options on incoming call:");
2578 for (opt = optstart; opt != NULL &&
2579 opt < US (ipopt) + optlen;)
2593 if (!string_format(p, pend-p, " %s [@%s",
2594 (*opt == IPOPT_SSRR)? "SSRR" : "LSRR",
2596 inet_ntoa(*((struct in_addr *)(&(ipopt->faddr))))))
2598 inet_ntoa(ipopt->ip_dst)))
2600 inet_ntoa(ipopt->ipopt_dst)))
2608 optcount = (opt[1] - 3) / sizeof(struct in_addr);
2610 while (optcount-- > 0)
2612 memcpy(&addr, adptr, sizeof(addr));
2613 if (!string_format(p, pend - p - 1, "%s%s",
2614 (optcount == 0)? ":" : "@", inet_ntoa(addr)))
2620 adptr += sizeof(struct in_addr);
2629 if (pend - p < 4 + 3*opt[1]) { opt = NULL; break; }
2632 for (i = 0; i < opt[1]; i++)
2633 p += sprintf(CS p, "%2.2x ", opt[i]);
2642 log_write(0, LOG_MAIN, "%s", big_buffer);
2644 /* Refuse any call with IP options. This is what tcpwrappers 7.5 does. */
2646 log_write(0, LOG_MAIN|LOG_REJECT,
2647 "connection from %s refused (IP options)", host_and_ident(FALSE));
2649 smtp_printf("554 SMTP service not available\r\n", FALSE);
2653 /* Length of options = 0 => there are no options */
2655 else DEBUG(D_receive) debug_printf("no IP options found\n");
2657 #endif /* HAVE_IPV6 && !defined(NO_IP_OPTIONS) */
2659 /* Set keep-alive in socket options. The option is on by default. This
2660 setting is an attempt to get rid of some hanging connections that stick in
2661 read() when the remote end (usually a dialup) goes away. */
2663 if (smtp_accept_keepalive && !sender_host_notsocket)
2664 ip_keepalive(fileno(smtp_out), sender_host_address, FALSE);
2666 /* If the current host matches host_lookup, set the name by doing a
2667 reverse lookup. On failure, sender_host_name will be NULL and
2668 host_lookup_failed will be TRUE. This may or may not be serious - optional
2671 if (verify_check_host(&host_lookup) == OK)
2673 (void)host_name_lookup();
2674 host_build_sender_fullhost();
2677 /* Delay this until we have the full name, if it is looked up. */
2679 set_process_info("handling incoming connection from %s",
2680 host_and_ident(FALSE));
2682 /* Expand smtp_receive_timeout, if needed */
2684 if (smtp_receive_timeout_s)
2687 if ( !(exp = expand_string(smtp_receive_timeout_s))
2689 || (smtp_receive_timeout = readconf_readtime(exp, 0, FALSE)) < 0
2691 log_write(0, LOG_MAIN|LOG_PANIC,
2692 "bad value for smtp_receive_timeout: '%s'", exp ? exp : US"");
2695 /* Test for explicit connection rejection */
2697 if (verify_check_host(&host_reject_connection) == OK)
2699 log_write(L_connection_reject, LOG_MAIN|LOG_REJECT, "refused connection "
2700 "from %s (host_reject_connection)", host_and_ident(FALSE));
2701 smtp_printf("554 SMTP service not available\r\n", FALSE);
2705 /* Test with TCP Wrappers if so configured. There is a problem in that
2706 hosts_ctl() returns 0 (deny) under a number of system failure circumstances,
2707 such as disks dying. In these cases, it is desirable to reject with a 4xx
2708 error instead of a 5xx error. There isn't a "right" way to detect such
2709 problems. The following kludge is used: errno is zeroed before calling
2710 hosts_ctl(). If the result is "reject", a 5xx error is given only if the
2711 value of errno is 0 or ENOENT (which happens if /etc/hosts.{allow,deny} does
2714 #ifdef USE_TCP_WRAPPERS
2716 if (!(tcp_wrappers_name = expand_string(tcp_wrappers_daemon_name)))
2717 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "Expansion of \"%s\" "
2718 "(tcp_wrappers_name) failed: %s", string_printing(tcp_wrappers_name),
2719 expand_string_message);
2721 if (!hosts_ctl(tcp_wrappers_name,
2722 sender_host_name ? CS sender_host_name : STRING_UNKNOWN,
2723 sender_host_address ? CS sender_host_address : STRING_UNKNOWN,
2724 sender_ident ? CS sender_ident : STRING_UNKNOWN))
2726 if (errno == 0 || errno == ENOENT)
2728 HDEBUG(D_receive) debug_printf("tcp wrappers rejection\n");
2729 log_write(L_connection_reject,
2730 LOG_MAIN|LOG_REJECT, "refused connection from %s "
2731 "(tcp wrappers)", host_and_ident(FALSE));
2732 smtp_printf("554 SMTP service not available\r\n", FALSE);
2736 int save_errno = errno;
2737 HDEBUG(D_receive) debug_printf("tcp wrappers rejected with unexpected "
2738 "errno value %d\n", save_errno);
2739 log_write(L_connection_reject,
2740 LOG_MAIN|LOG_REJECT, "temporarily refused connection from %s "
2741 "(tcp wrappers errno=%d)", host_and_ident(FALSE), save_errno);
2742 smtp_printf("451 Temporary local problem - please try later\r\n", FALSE);
2748 /* Check for reserved slots. The value of smtp_accept_count has already been
2749 incremented to include this process. */
2751 if (smtp_accept_max > 0 &&
2752 smtp_accept_count > smtp_accept_max - smtp_accept_reserve)
2754 if ((rc = verify_check_host(&smtp_reserve_hosts)) != OK)
2756 log_write(L_connection_reject,
2757 LOG_MAIN, "temporarily refused connection from %s: not in "
2758 "reserve list: connected=%d max=%d reserve=%d%s",
2759 host_and_ident(FALSE), smtp_accept_count - 1, smtp_accept_max,
2760 smtp_accept_reserve, (rc == DEFER)? " (lookup deferred)" : "");
2761 smtp_printf("421 %s: Too many concurrent SMTP connections; "
2762 "please try again later\r\n", FALSE, smtp_active_hostname);
2765 reserved_host = TRUE;
2768 /* If a load level above which only messages from reserved hosts are
2769 accepted is set, check the load. For incoming calls via the daemon, the
2770 check is done in the superior process if there are no reserved hosts, to
2771 save a fork. In all cases, the load average will already be available
2772 in a global variable at this point. */
2774 if (smtp_load_reserve >= 0 &&
2775 load_average > smtp_load_reserve &&
2777 verify_check_host(&smtp_reserve_hosts) != OK)
2779 log_write(L_connection_reject,
2780 LOG_MAIN, "temporarily refused connection from %s: not in "
2781 "reserve list and load average = %.2f", host_and_ident(FALSE),
2782 (double)load_average/1000.0);
2783 smtp_printf("421 %s: Too much load; please try again later\r\n", FALSE,
2784 smtp_active_hostname);
2788 /* Determine whether unqualified senders or recipients are permitted
2789 for this host. Unfortunately, we have to do this every time, in order to
2790 set the flags so that they can be inspected when considering qualifying
2791 addresses in the headers. For a site that permits no qualification, this
2792 won't take long, however. */
2794 allow_unqualified_sender =
2795 verify_check_host(&sender_unqualified_hosts) == OK;
2797 allow_unqualified_recipient =
2798 verify_check_host(&recipient_unqualified_hosts) == OK;
2800 /* Determine whether HELO/EHLO is required for this host. The requirement
2801 can be hard or soft. */
2803 helo_required = verify_check_host(&helo_verify_hosts) == OK;
2805 helo_verify = verify_check_host(&helo_try_verify_hosts) == OK;
2807 /* Determine whether this hosts is permitted to send syntactic junk
2808 after a HELO or EHLO command. */
2810 helo_accept_junk = verify_check_host(&helo_accept_junk_hosts) == OK;
2813 /* For batch SMTP input we are now done. */
2815 if (smtp_batched_input) return TRUE;
2817 /* If valid Proxy Protocol source is connecting, set up session.
2818 * Failure will not allow any SMTP function other than QUIT. */
2820 #ifdef SUPPORT_PROXY
2821 proxy_session = FALSE;
2822 proxy_session_failed = FALSE;
2823 if (check_proxy_protocol_host())
2824 setup_proxy_protocol_host();
2827 /* Start up TLS if tls_on_connect is set. This is for supporting the legacy
2828 smtps port for use with older style SSL MTAs. */
2831 if (tls_in.on_connect)
2833 if (tls_server_start(tls_require_ciphers, &user_msg) != OK)
2834 return smtp_log_tls_fail(user_msg);
2835 cmd_list[CMD_LIST_TLS_AUTH].is_mail_cmd = TRUE;
2839 /* Run the connect ACL if it exists */
2842 if (acl_smtp_connect)
2845 if ((rc = acl_check(ACL_WHERE_CONNECT, NULL, acl_smtp_connect, &user_msg,
2848 (void) smtp_handle_acl_fail(ACL_WHERE_CONNECT, rc, user_msg, log_msg);
2853 /* Output the initial message for a two-way SMTP connection. It may contain
2854 newlines, which then cause a multi-line response to be given. */
2856 code = US"220"; /* Default status code */
2857 esc = US""; /* Default extended status code */
2858 esclen = 0; /* Length of esc */
2862 if (!(s = expand_string(smtp_banner)))
2863 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "Expansion of \"%s\" (smtp_banner) "
2864 "failed: %s", smtp_banner, expand_string_message);
2870 smtp_message_code(&code, &codelen, &s, NULL, TRUE);
2874 esclen = codelen - 4;
2878 /* Remove any terminating newlines; might as well remove trailing space too */
2881 while (p > s && isspace(p[-1])) p--;
2884 /* It seems that CC:Mail is braindead, and assumes that the greeting message
2885 is all contained in a single IP packet. The original code wrote out the
2886 greeting using several calls to fprint/fputc, and on busy servers this could
2887 cause it to be split over more than one packet - which caused CC:Mail to fall
2888 over when it got the second part of the greeting after sending its first
2889 command. Sigh. To try to avoid this, build the complete greeting message
2890 first, and output it in one fell swoop. This gives a better chance of it
2891 ending up as a single packet. */
2893 ss = string_get(256);
2896 do /* At least once, in case we have an empty string */
2899 uschar *linebreak = Ustrchr(p, '\n');
2900 ss = string_catn(ss, code, 3);
2904 ss = string_catn(ss, US" ", 1);
2908 len = linebreak - p;
2909 ss = string_catn(ss, US"-", 1);
2911 ss = string_catn(ss, esc, esclen);
2912 ss = string_catn(ss, p, len);
2913 ss = string_catn(ss, US"\r\n", 2);
2919 /* Before we write the banner, check that there is no input pending, unless
2920 this synchronisation check is disabled. */
2924 unsigned n = smtp_inend - smtp_inptr;
2927 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP protocol "
2928 "synchronization error (input sent without waiting for greeting): "
2929 "rejected connection from %s input=\"%s\"", host_and_ident(TRUE),
2930 string_printing(string_copyn(smtp_inptr, n)));
2931 smtp_printf("554 SMTP synchronization error\r\n", FALSE);
2935 /* Now output the banner */
2937 smtp_printf("%s", FALSE, string_from_gstring(ss));
2939 /* Attempt to see if we sent the banner before the last ACK of the 3-way
2940 handshake arrived. If so we must have managed a TFO. */
2953 /*************************************************
2954 * Handle SMTP syntax and protocol errors *
2955 *************************************************/
2957 /* Write to the log for SMTP syntax errors in incoming commands, if configured
2958 to do so. Then transmit the error response. The return value depends on the
2959 number of syntax and protocol errors in this SMTP session.
2962 type error type, given as a log flag bit
2963 code response code; <= 0 means don't send a response
2964 data data to reflect in the response (can be NULL)
2965 errmess the error message
2967 Returns: -1 limit of syntax/protocol errors NOT exceeded
2968 +1 limit of syntax/protocol errors IS exceeded
2970 These values fit in with the values of the "done" variable in the main
2971 processing loop in smtp_setup_msg(). */
2974 synprot_error(int type, int code, uschar *data, uschar *errmess)
2978 log_write(type, LOG_MAIN, "SMTP %s error in \"%s\" %s %s",
2979 (type == L_smtp_syntax_error)? "syntax" : "protocol",
2980 string_printing(smtp_cmd_buffer), host_and_ident(TRUE), errmess);
2982 if (++synprot_error_count > smtp_max_synprot_errors)
2985 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
2986 "syntax or protocol errors (last command was \"%s\")",
2987 host_and_ident(FALSE), string_printing(smtp_cmd_buffer));
2992 smtp_printf("%d%c%s%s%s\r\n", FALSE, code, yield == 1 ? '-' : ' ',
2993 data ? data : US"", data ? US": " : US"", errmess);
2995 smtp_printf("%d Too many syntax or protocol errors\r\n", FALSE, code);
3004 /*************************************************
3005 * Send SMTP response, possibly multiline *
3006 *************************************************/
3008 /* There are, it seems, broken clients out there that cannot handle multiline
3009 responses. If no_multiline_responses is TRUE (it can be set from an ACL), we
3010 output nothing for non-final calls, and only the first line for anything else.
3013 code SMTP code, may involve extended status codes
3014 codelen length of smtp code; if > 4 there's an ESC
3015 final FALSE if the last line isn't the final line
3016 msg message text, possibly containing newlines
3022 smtp_respond(uschar* code, int codelen, BOOL final, uschar *msg)
3027 if (!final && no_multiline_responses) return;
3032 esclen = codelen - 4;
3035 /* If this is the first output for a (non-batch) RCPT command, see if all RCPTs
3036 have had the same. Note: this code is also present in smtp_printf(). It would
3037 be tidier to have it only in one place, but when it was added, it was easier to
3038 do it that way, so as not to have to mess with the code for the RCPT command,
3039 which sometimes uses smtp_printf() and sometimes smtp_respond(). */
3041 if (rcpt_in_progress)
3043 if (rcpt_smtp_response == NULL)
3044 rcpt_smtp_response = string_copy(msg);
3045 else if (rcpt_smtp_response_same &&
3046 Ustrcmp(rcpt_smtp_response, msg) != 0)
3047 rcpt_smtp_response_same = FALSE;
3048 rcpt_in_progress = FALSE;
3051 /* Now output the message, splitting it up into multiple lines if necessary.
3052 We only handle pipelining these responses as far as nonfinal/final groups,
3053 not the whole MAIL/RCPT/DATA response set. */
3057 uschar *nl = Ustrchr(msg, '\n');
3060 smtp_printf("%.3s%c%.*s%s\r\n", !final, code, final ? ' ':'-', esclen, esc, msg);
3063 else if (nl[1] == 0 || no_multiline_responses)
3065 smtp_printf("%.3s%c%.*s%.*s\r\n", !final, code, final ? ' ':'-', esclen, esc,
3066 (int)(nl - msg), msg);
3071 smtp_printf("%.3s-%.*s%.*s\r\n", TRUE, code, esclen, esc, (int)(nl - msg), msg);
3073 while (isspace(*msg)) msg++;
3081 /*************************************************
3082 * Parse user SMTP message *
3083 *************************************************/
3085 /* This function allows for user messages overriding the response code details
3086 by providing a suitable response code string at the start of the message
3087 user_msg. Check the message for starting with a response code and optionally an
3088 extended status code. If found, check that the first digit is valid, and if so,
3089 change the code pointer and length to use the replacement. An invalid code
3090 causes a panic log; in this case, if the log messages is the same as the user
3091 message, we must also adjust the value of the log message to show the code that
3092 is actually going to be used (the original one).
3094 This function is global because it is called from receive.c as well as within
3097 Note that the code length returned includes the terminating whitespace
3098 character, which is always included in the regex match.
3101 code SMTP code, may involve extended status codes
3102 codelen length of smtp code; if > 4 there's an ESC
3104 log_msg optional log message, to be adjusted with the new SMTP code
3105 check_valid if true, verify the response code
3111 smtp_message_code(uschar **code, int *codelen, uschar **msg, uschar **log_msg,
3117 if (!msg || !*msg) return;
3119 if ((n = pcre_exec(regex_smtp_code, NULL, CS *msg, Ustrlen(*msg), 0,
3120 PCRE_EOPT, ovector, sizeof(ovector)/sizeof(int))) < 0) return;
3122 if (check_valid && (*msg)[0] != (*code)[0])
3124 log_write(0, LOG_MAIN|LOG_PANIC, "configured error code starts with "
3125 "incorrect digit (expected %c) in \"%s\"", (*code)[0], *msg);
3126 if (log_msg != NULL && *log_msg == *msg)
3127 *log_msg = string_sprintf("%s %s", *code, *log_msg + ovector[1]);
3132 *codelen = ovector[1]; /* Includes final space */
3134 *msg += ovector[1]; /* Chop the code off the message */
3141 /*************************************************
3142 * Handle an ACL failure *
3143 *************************************************/
3145 /* This function is called when acl_check() fails. As well as calls from within
3146 this module, it is called from receive.c for an ACL after DATA. It sorts out
3147 logging the incident, and sends the error response. A message containing
3148 newlines is turned into a multiline SMTP response, but for logging, only the
3151 There's a table of default permanent failure response codes to use in
3152 globals.c, along with the table of names. VFRY is special. Despite RFC1123 it
3153 defaults disabled in Exim. However, discussion in connection with RFC 821bis
3154 (aka RFC 2821) has concluded that the response should be 252 in the disabled
3155 state, because there are broken clients that try VRFY before RCPT. A 5xx
3156 response should be given only when the address is positively known to be
3157 undeliverable. Sigh. We return 252 if there is no VRFY ACL or it provides
3158 no explicit code, but if there is one we let it know best.
3159 Also, for ETRN, 458 is given on refusal, and for AUTH, 503.
3161 From Exim 4.63, it is possible to override the response code details by
3162 providing a suitable response code string at the start of the message provided
3163 in user_msg. The code's first digit is checked for validity.
3166 where where the ACL was called from
3168 user_msg a message that can be included in an SMTP response
3169 log_msg a message for logging
3171 Returns: 0 in most cases
3172 2 if the failure code was FAIL_DROP, in which case the
3173 SMTP connection should be dropped (this value fits with the
3174 "done" variable in smtp_setup_msg() below)
3178 smtp_handle_acl_fail(int where, int rc, uschar *user_msg, uschar *log_msg)
3180 BOOL drop = rc == FAIL_DROP;
3184 uschar *sender_info = US"";
3186 #ifdef WITH_CONTENT_SCAN
3187 where == ACL_WHERE_MIME ? US"during MIME ACL checks" :
3189 where == ACL_WHERE_PREDATA ? US"DATA" :
3190 where == ACL_WHERE_DATA ? US"after DATA" :
3191 #ifndef DISABLE_PRDR
3192 where == ACL_WHERE_PRDR ? US"after DATA PRDR" :
3195 string_sprintf("%s %s", acl_wherenames[where], smtp_cmd_data) :
3196 string_sprintf("%s in \"connect\" ACL", acl_wherenames[where]);
3198 if (drop) rc = FAIL;
3200 /* Set the default SMTP code, and allow a user message to change it. */
3202 smtp_code = rc == FAIL ? acl_wherecodes[where] : US"451";
3203 smtp_message_code(&smtp_code, &codelen, &user_msg, &log_msg,
3204 where != ACL_WHERE_VRFY);
3206 /* We used to have sender_address here; however, there was a bug that was not
3207 updating sender_address after a rewrite during a verify. When this bug was
3208 fixed, sender_address at this point became the rewritten address. I'm not sure
3209 this is what should be logged, so I've changed to logging the unrewritten
3210 address to retain backward compatibility. */
3212 #ifndef WITH_CONTENT_SCAN
3213 if (where == ACL_WHERE_RCPT || where == ACL_WHERE_DATA)
3215 if (where == ACL_WHERE_RCPT || where == ACL_WHERE_DATA || where == ACL_WHERE_MIME)
3218 sender_info = string_sprintf("F=<%s>%s%s%s%s ",
3219 sender_address_unrewritten ? sender_address_unrewritten : sender_address,
3220 sender_host_authenticated ? US" A=" : US"",
3221 sender_host_authenticated ? sender_host_authenticated : US"",
3222 sender_host_authenticated && authenticated_id ? US":" : US"",
3223 sender_host_authenticated && authenticated_id ? authenticated_id : US""
3227 /* If there's been a sender verification failure with a specific message, and
3228 we have not sent a response about it yet, do so now, as a preliminary line for
3229 failures, but not defers. However, always log it for defer, and log it for fail
3230 unless the sender_verify_fail log selector has been turned off. */
3232 if (sender_verified_failed &&
3233 !testflag(sender_verified_failed, af_sverify_told))
3235 BOOL save_rcpt_in_progress = rcpt_in_progress;
3236 rcpt_in_progress = FALSE; /* So as not to treat these as the error */
3238 setflag(sender_verified_failed, af_sverify_told);
3240 if (rc != FAIL || LOGGING(sender_verify_fail))
3241 log_write(0, LOG_MAIN|LOG_REJECT, "%s sender verify %s for <%s>%s",
3242 host_and_ident(TRUE),
3243 ((sender_verified_failed->special_action & 255) == DEFER)? "defer":"fail",
3244 sender_verified_failed->address,
3245 (sender_verified_failed->message == NULL)? US"" :
3246 string_sprintf(": %s", sender_verified_failed->message));
3248 if (rc == FAIL && sender_verified_failed->user_message)
3249 smtp_respond(smtp_code, codelen, FALSE, string_sprintf(
3250 testflag(sender_verified_failed, af_verify_pmfail)?
3251 "Postmaster verification failed while checking <%s>\n%s\n"
3252 "Several RFCs state that you are required to have a postmaster\n"
3253 "mailbox for each mail domain. This host does not accept mail\n"
3254 "from domains whose servers reject the postmaster address."
3256 testflag(sender_verified_failed, af_verify_nsfail)?
3257 "Callback setup failed while verifying <%s>\n%s\n"
3258 "The initial connection, or a HELO or MAIL FROM:<> command was\n"
3259 "rejected. Refusing MAIL FROM:<> does not help fight spam, disregards\n"
3260 "RFC requirements, and stops you from receiving standard bounce\n"
3261 "messages. This host does not accept mail from domains whose servers\n"
3264 "Verification failed for <%s>\n%s",
3265 sender_verified_failed->address,
3266 sender_verified_failed->user_message));
3268 rcpt_in_progress = save_rcpt_in_progress;
3271 /* Sort out text for logging */
3273 log_msg = log_msg ? string_sprintf(": %s", log_msg) : US"";
3274 if ((lognl = Ustrchr(log_msg, '\n'))) *lognl = 0;
3276 /* Send permanent failure response to the command, but the code used isn't
3277 always a 5xx one - see comments at the start of this function. If the original
3278 rc was FAIL_DROP we drop the connection and yield 2. */
3281 smtp_respond(smtp_code, codelen, TRUE,
3282 user_msg ? user_msg : US"Administrative prohibition");
3284 /* Send temporary failure response to the command. Don't give any details,
3285 unless acl_temp_details is set. This is TRUE for a callout defer, a "defer"
3286 verb, and for a header verify when smtp_return_error_details is set.
3288 This conditional logic is all somewhat of a mess because of the odd
3289 interactions between temp_details and return_error_details. One day it should
3290 be re-implemented in a tidier fashion. */
3293 if (acl_temp_details && user_msg)
3295 if ( smtp_return_error_details
3296 && sender_verified_failed
3297 && sender_verified_failed->message
3299 smtp_respond(smtp_code, codelen, FALSE, sender_verified_failed->message);
3301 smtp_respond(smtp_code, codelen, TRUE, user_msg);
3304 smtp_respond(smtp_code, codelen, TRUE,
3305 US"Temporary local problem - please try later");
3307 /* Log the incident to the logs that are specified by log_reject_target
3308 (default main, reject). This can be empty to suppress logging of rejections. If
3309 the connection is not forcibly to be dropped, return 0. Otherwise, log why it
3310 is closing if required and return 2. */
3312 if (log_reject_target != 0)
3315 gstring * g = s_tlslog(NULL);
3316 uschar * tls = string_from_gstring(g);
3317 if (!tls) tls = US"";
3319 uschar * tls = US"";
3321 log_write(where == ACL_WHERE_CONNECT ? L_connection_reject : 0,
3322 log_reject_target, "%s%s%s %s%srejected %s%s",
3323 LOGGING(dnssec) && sender_host_dnssec ? US" DS" : US"",
3324 host_and_ident(TRUE),
3327 rc == FAIL ? US"" : US"temporarily ",
3331 if (!drop) return 0;
3333 log_write(L_smtp_connection, LOG_MAIN, "%s closed by DROP in ACL",
3334 smtp_get_connection_info());
3336 /* Run the not-quit ACL, but without any custom messages. This should not be a
3337 problem, because we get here only if some other ACL has issued "drop", and
3338 in that case, *its* custom messages will have been used above. */
3340 smtp_notquit_exit(US"acl-drop", NULL, NULL);
3347 /*************************************************
3348 * Handle SMTP exit when QUIT is not given *
3349 *************************************************/
3351 /* This function provides a logging/statistics hook for when an SMTP connection
3352 is dropped on the floor or the other end goes away. It's a global function
3353 because it's called from receive.c as well as this module. As well as running
3354 the NOTQUIT ACL, if there is one, this function also outputs a final SMTP
3355 response, either with a custom message from the ACL, or using a default. There
3356 is one case, however, when no message is output - after "drop". In that case,
3357 the ACL that obeyed "drop" has already supplied the custom message, and NULL is
3358 passed to this function.
3360 In case things go wrong while processing this function, causing an error that
3361 may re-enter this function, there is a recursion check.
3364 reason What $smtp_notquit_reason will be set to in the ACL;
3365 if NULL, the ACL is not run
3366 code The error code to return as part of the response
3367 defaultrespond The default message if there's no user_msg
3373 smtp_notquit_exit(uschar *reason, uschar *code, uschar *defaultrespond, ...)
3376 uschar *user_msg = NULL;
3377 uschar *log_msg = NULL;
3379 /* Check for recursive acll */
3381 if (smtp_exit_function_called)
3383 log_write(0, LOG_PANIC, "smtp_notquit_exit() called more than once (%s)",
3387 smtp_exit_function_called = TRUE;
3389 /* Call the not-QUIT ACL, if there is one, unless no reason is given. */
3391 if (acl_smtp_notquit && reason)
3393 smtp_notquit_reason = reason;
3394 if ((rc = acl_check(ACL_WHERE_NOTQUIT, NULL, acl_smtp_notquit, &user_msg,
3395 &log_msg)) == ERROR)
3396 log_write(0, LOG_MAIN|LOG_PANIC, "ACL for not-QUIT returned ERROR: %s",
3400 /* Write an SMTP response if we are expected to give one. As the default
3401 responses are all internal, they should always fit in the buffer, but code a
3402 warning, just in case. Note that string_vformat() still leaves a complete
3403 string, even if it is incomplete. */
3405 if (code && defaultrespond)
3408 smtp_respond(code, 3, TRUE, user_msg);
3413 va_start(ap, defaultrespond);
3414 if (!string_vformat(buffer, sizeof(buffer), CS defaultrespond, ap))
3415 log_write(0, LOG_MAIN|LOG_PANIC, "string too large in smtp_notquit_exit()");
3416 smtp_printf("%s %s\r\n", FALSE, code, buffer);
3426 /*************************************************
3427 * Verify HELO argument *
3428 *************************************************/
3430 /* This function is called if helo_verify_hosts or helo_try_verify_hosts is
3431 matched. It is also called from ACL processing if verify = helo is used and
3432 verification was not previously tried (i.e. helo_try_verify_hosts was not
3433 matched). The result of its processing is to set helo_verified and
3434 helo_verify_failed. These variables should both be FALSE for this function to
3437 Note that EHLO/HELO is legitimately allowed to quote an address literal. Allow
3438 for IPv6 ::ffff: literals.
3441 Returns: TRUE if testing was completed;
3442 FALSE on a temporary failure
3446 smtp_verify_helo(void)
3450 HDEBUG(D_receive) debug_printf("verifying EHLO/HELO argument \"%s\"\n",
3453 if (sender_helo_name == NULL)
3455 HDEBUG(D_receive) debug_printf("no EHLO/HELO command was issued\n");
3458 /* Deal with the case of -bs without an IP address */
3460 else if (sender_host_address == NULL)
3462 HDEBUG(D_receive) debug_printf("no client IP address: assume success\n");
3463 helo_verified = TRUE;
3466 /* Deal with the more common case when there is a sending IP address */
3468 else if (sender_helo_name[0] == '[')
3470 helo_verified = Ustrncmp(sender_helo_name+1, sender_host_address,
3471 Ustrlen(sender_host_address)) == 0;
3476 if (strncmpic(sender_host_address, US"::ffff:", 7) == 0)
3477 helo_verified = Ustrncmp(sender_helo_name + 1,
3478 sender_host_address + 7, Ustrlen(sender_host_address) - 7) == 0;
3483 { if (helo_verified) debug_printf("matched host address\n"); }
3486 /* Do a reverse lookup if one hasn't already given a positive or negative
3487 response. If that fails, or the name doesn't match, try checking with a forward
3492 if (sender_host_name == NULL && !host_lookup_failed)
3493 yield = host_name_lookup() != DEFER;
3495 /* If a host name is known, check it and all its aliases. */
3497 if (sender_host_name)
3498 if ((helo_verified = strcmpic(sender_host_name, sender_helo_name) == 0))
3500 sender_helo_dnssec = sender_host_dnssec;
3501 HDEBUG(D_receive) debug_printf("matched host name\n");
3505 uschar **aliases = sender_host_aliases;
3507 if ((helo_verified = strcmpic(*aliases++, sender_helo_name) == 0))
3509 sender_helo_dnssec = sender_host_dnssec;
3513 HDEBUG(D_receive) if (helo_verified)
3514 debug_printf("matched alias %s\n", *(--aliases));
3517 /* Final attempt: try a forward lookup of the helo name */
3526 h.name = sender_helo_name;
3533 HDEBUG(D_receive) debug_printf("getting IP address for %s\n",
3535 rc = host_find_bydns(&h, NULL, HOST_FIND_BY_A | HOST_FIND_BY_AAAA,
3536 NULL, NULL, NULL, &d, NULL, NULL);
3537 if (rc == HOST_FOUND || rc == HOST_FOUND_LOCAL)
3538 for (hh = &h; hh; hh = hh->next)
3539 if (Ustrcmp(hh->address, sender_host_address) == 0)
3541 helo_verified = TRUE;
3542 if (h.dnssec == DS_YES) sender_helo_dnssec = TRUE;
3545 debug_printf("IP address for %s matches calling address\n"
3546 "Forward DNS security status: %sverified\n",
3547 sender_helo_name, sender_helo_dnssec ? "" : "un");
3554 if (!helo_verified) helo_verify_failed = TRUE; /* We've tried ... */
3561 /*************************************************
3562 * Send user response message *
3563 *************************************************/
3565 /* This function is passed a default response code and a user message. It calls
3566 smtp_message_code() to check and possibly modify the response code, and then
3567 calls smtp_respond() to transmit the response. I put this into a function
3568 just to avoid a lot of repetition.
3571 code the response code
3572 user_msg the user message
3578 smtp_user_msg(uschar *code, uschar *user_msg)
3581 smtp_message_code(&code, &len, &user_msg, NULL, TRUE);
3582 smtp_respond(code, len, TRUE, user_msg);
3588 smtp_in_auth(auth_instance *au, uschar ** s, uschar ** ss)
3590 const uschar *set_id = NULL;
3593 /* Run the checking code, passing the remainder of the command line as
3594 data. Initials the $auth<n> variables as empty. Initialize $0 empty and set
3595 it as the only set numerical variable. The authenticator may set $auth<n>
3596 and also set other numeric variables. The $auth<n> variables are preferred
3597 nowadays; the numerical variables remain for backwards compatibility.
3599 Afterwards, have a go at expanding the set_id string, even if
3600 authentication failed - for bad passwords it can be useful to log the
3601 userid. On success, require set_id to expand and exist, and put it in
3602 authenticated_id. Save this in permanent store, as the working store gets
3603 reset at HELO, RSET, etc. */
3605 for (i = 0; i < AUTH_VARS; i++) auth_vars[i] = NULL;
3607 expand_nlength[0] = 0; /* $0 contains nothing */
3609 rc = (au->info->servercode)(au, smtp_cmd_data);
3610 if (au->set_id) set_id = expand_string(au->set_id);
3611 expand_nmax = -1; /* Reset numeric variables */
3612 for (i = 0; i < AUTH_VARS; i++) auth_vars[i] = NULL; /* Reset $auth<n> */
3614 /* The value of authenticated_id is stored in the spool file and printed in
3615 log lines. It must not contain binary zeros or newline characters. In
3616 normal use, it never will, but when playing around or testing, this error
3617 can (did) happen. To guard against this, ensure that the id contains only
3618 printing characters. */
3620 if (set_id) set_id = string_printing(set_id);
3622 /* For the non-OK cases, set up additional logging data if set_id
3626 set_id = set_id && *set_id
3627 ? string_sprintf(" (set_id=%s)", set_id) : US"";
3629 /* Switch on the result */
3634 if (!au->set_id || set_id) /* Complete success */
3636 if (set_id) authenticated_id = string_copy_malloc(set_id);
3637 sender_host_authenticated = au->name;
3638 sender_host_auth_pubname = au->public_name;
3639 authentication_failed = FALSE;
3640 authenticated_fail_id = NULL; /* Impossible to already be set? */
3643 (sender_host_address ? protocols : protocols_local)
3644 [pextend + pauthed + (tls_in.active >= 0 ? pcrpted:0)];
3645 *s = *ss = US"235 Authentication succeeded";
3646 authenticated_by = au;
3650 /* Authentication succeeded, but we failed to expand the set_id string.
3651 Treat this as a temporary error. */
3653 auth_defer_msg = expand_string_message;
3657 if (set_id) authenticated_fail_id = string_copy_malloc(set_id);
3658 *s = string_sprintf("435 Unable to authenticate at present%s",
3659 auth_defer_user_msg);
3660 *ss = string_sprintf("435 Unable to authenticate at present%s: %s",
3661 set_id, auth_defer_msg);
3665 *s = *ss = US"501 Invalid base64 data";
3669 *s = *ss = US"501 Authentication cancelled";
3673 *s = *ss = US"553 Initial data not expected";
3677 if (set_id) authenticated_fail_id = string_copy_malloc(set_id);
3678 *s = US"535 Incorrect authentication data";
3679 *ss = string_sprintf("535 Incorrect authentication data%s", set_id);
3683 if (set_id) authenticated_fail_id = string_copy_malloc(set_id);
3684 *s = US"435 Internal error";
3685 *ss = string_sprintf("435 Internal error%s: return %d from authentication "
3686 "check", set_id, rc);
3698 qualify_recipient(uschar ** recipient, uschar * smtp_cmd_data, uschar * tag)
3701 if (allow_unqualified_recipient || strcmpic(*recipient, US"postmaster") == 0)
3703 DEBUG(D_receive) debug_printf("unqualified address %s accepted\n",
3705 rd = Ustrlen(recipient) + 1;
3706 *recipient = rewrite_address_qualify(*recipient, TRUE);
3709 smtp_printf("501 %s: recipient address must contain a domain\r\n", FALSE,
3711 log_write(L_smtp_syntax_error,
3712 LOG_MAIN|LOG_REJECT, "unqualified %s rejected: <%s> %s%s",
3713 tag, *recipient, host_and_ident(TRUE), host_lookup_msg);
3721 smtp_quit_handler(uschar ** user_msgp, uschar ** log_msgp)
3724 incomplete_transaction_log(US"QUIT");
3727 int rc = acl_check(ACL_WHERE_QUIT, NULL, acl_smtp_quit, user_msgp, log_msgp);
3729 log_write(0, LOG_MAIN|LOG_PANIC, "ACL for QUIT returned ERROR: %s",
3733 smtp_respond(US"221", 3, TRUE, *user_msgp);
3735 smtp_printf("221 %s closing connection\r\n", FALSE, smtp_active_hostname);
3738 tls_close(TRUE, TLS_SHUTDOWN_NOWAIT);
3741 log_write(L_smtp_connection, LOG_MAIN, "%s closed by QUIT",
3742 smtp_get_connection_info());
3747 smtp_rset_handler(void)
3750 incomplete_transaction_log(US"RSET");
3751 smtp_printf("250 Reset OK\r\n", FALSE);
3752 cmd_list[CMD_LIST_RSET].is_mail_cmd = FALSE;
3757 /*************************************************
3758 * Initialize for SMTP incoming message *
3759 *************************************************/
3761 /* This function conducts the initial dialogue at the start of an incoming SMTP
3762 message, and builds a list of recipients. However, if the incoming message
3763 is part of a batch (-bS option) a separate function is called since it would
3764 be messy having tests splattered about all over this function. This function
3765 therefore handles the case where interaction is occurring. The input and output
3766 files are set up in smtp_in and smtp_out.
3768 The global recipients_list is set to point to a vector of recipient_item
3769 blocks, whose number is given by recipients_count. This is extended by the
3770 receive_add_recipient() function. The global variable sender_address is set to
3771 the sender's address. The yield is +1 if a message has been successfully
3772 started, 0 if a QUIT command was encountered or the connection was refused from
3773 the particular host, or -1 if the connection was lost.
3777 Returns: > 0 message successfully started (reached DATA)
3778 = 0 QUIT read or end of file reached or call refused
3783 smtp_setup_msg(void)
3786 BOOL toomany = FALSE;
3787 BOOL discarded = FALSE;
3788 BOOL last_was_rej_mail = FALSE;
3789 BOOL last_was_rcpt = FALSE;
3790 void *reset_point = store_get(0);
3792 DEBUG(D_receive) debug_printf("smtp_setup_msg entered\n");
3794 /* Reset for start of new message. We allow one RSET not to be counted as a
3795 nonmail command, for those MTAs that insist on sending it between every
3796 message. Ditto for EHLO/HELO and for STARTTLS, to allow for going in and out of
3797 TLS between messages (an Exim client may do this if it has messages queued up
3798 for the host). Note: we do NOT reset AUTH at this point. */
3800 smtp_reset(reset_point);
3801 message_ended = END_NOTSTARTED;
3803 chunking_state = chunking_offered ? CHUNKING_OFFERED : CHUNKING_NOT_OFFERED;
3805 cmd_list[CMD_LIST_RSET].is_mail_cmd = TRUE;
3806 cmd_list[CMD_LIST_HELO].is_mail_cmd = TRUE;
3807 cmd_list[CMD_LIST_EHLO].is_mail_cmd = TRUE;
3809 cmd_list[CMD_LIST_STARTTLS].is_mail_cmd = TRUE;
3812 /* Set the local signal handler for SIGTERM - it tries to end off tidily */
3814 os_non_restarting_signal(SIGTERM, command_sigterm_handler);
3816 /* Batched SMTP is handled in a different function. */
3818 if (smtp_batched_input) return smtp_setup_batch_msg();
3820 /* Deal with SMTP commands. This loop is exited by setting done to a POSITIVE
3821 value. The values are 2 larger than the required yield of the function. */
3825 const uschar **argv;
3826 uschar *etrn_command;
3827 uschar *etrn_serialize_key;
3829 uschar *log_msg, *smtp_code;
3830 uschar *user_msg = NULL;
3831 uschar *recipient = NULL;
3832 uschar *hello = NULL;
3834 BOOL was_rej_mail = FALSE;
3835 BOOL was_rcpt = FALSE;
3836 void (*oldsignal)(int);
3838 int start, end, sender_domain, recipient_domain;
3842 uschar *orcpt = NULL;
3847 /* Check once per STARTTLS or SSL-on-connect for a TLS AUTH */
3848 if ( tls_in.active >= 0
3850 && tls_in.certificate_verified
3851 && cmd_list[CMD_LIST_TLS_AUTH].is_mail_cmd
3854 cmd_list[CMD_LIST_TLS_AUTH].is_mail_cmd = FALSE;
3856 for (au = auths; au; au = au->next)
3857 if (strcmpic(US"tls", au->driver_name) == 0)
3860 && (rc = acl_check(ACL_WHERE_AUTH, NULL, acl_smtp_auth,
3861 &user_msg, &log_msg)) != OK
3863 done = smtp_handle_acl_fail(ACL_WHERE_AUTH, rc, user_msg, log_msg);
3866 smtp_cmd_data = NULL;
3868 if (smtp_in_auth(au, &s, &ss) == OK)
3869 { DEBUG(D_auth) debug_printf("tls auth succeeded\n"); }
3871 { DEBUG(D_auth) debug_printf("tls auth not succeeded\n"); }
3879 if (smtp_in) /* Avoid pure-ACKs while in cmd pingpong phase */
3880 (void) setsockopt(fileno(smtp_in), IPPROTO_TCP, TCP_QUICKACK,
3881 US &off, sizeof(off));
3884 switch(smtp_read_command(TRUE, GETC_BUFFER_UNLIMITED))
3886 /* The AUTH command is not permitted to occur inside a transaction, and may
3887 occur successfully only once per connection. Actually, that isn't quite
3888 true. When TLS is started, all previous information about a connection must
3889 be discarded, so a new AUTH is permitted at that time.
3891 AUTH may only be used when it has been advertised. However, it seems that
3892 there are clients that send AUTH when it hasn't been advertised, some of
3893 them even doing this after HELO. And there are MTAs that accept this. Sigh.
3894 So there's a get-out that allows this to happen.
3896 AUTH is initially labelled as a "nonmail command" so that one occurrence
3897 doesn't get counted. We change the label here so that multiple failing
3898 AUTHS will eventually hit the nonmail threshold. */
3902 authentication_failed = TRUE;
3903 cmd_list[CMD_LIST_AUTH].is_mail_cmd = FALSE;
3905 if (!auth_advertised && !allow_auth_unadvertised)
3907 done = synprot_error(L_smtp_protocol_error, 503, NULL,
3908 US"AUTH command used when not advertised");
3911 if (sender_host_authenticated)
3913 done = synprot_error(L_smtp_protocol_error, 503, NULL,
3914 US"already authenticated");
3919 done = synprot_error(L_smtp_protocol_error, 503, NULL,
3920 US"not permitted in mail transaction");
3927 && (rc = acl_check(ACL_WHERE_AUTH, NULL, acl_smtp_auth,
3928 &user_msg, &log_msg)) != OK
3931 done = smtp_handle_acl_fail(ACL_WHERE_AUTH, rc, user_msg, log_msg);
3935 /* Find the name of the requested authentication mechanism. */
3938 while ((c = *smtp_cmd_data) != 0 && !isspace(c))
3940 if (!isalnum(c) && c != '-' && c != '_')
3942 done = synprot_error(L_smtp_syntax_error, 501, NULL,
3943 US"invalid character in authentication mechanism name");
3949 /* If not at the end of the line, we must be at white space. Terminate the
3950 name and move the pointer on to any data that may be present. */
3952 if (*smtp_cmd_data != 0)
3954 *smtp_cmd_data++ = 0;
3955 while (isspace(*smtp_cmd_data)) smtp_cmd_data++;
3958 /* Search for an authentication mechanism which is configured for use
3959 as a server and which has been advertised (unless, sigh, allow_auth_
3960 unadvertised is set). */
3962 for (au = auths; au; au = au->next)
3963 if (strcmpic(s, au->public_name) == 0 && au->server &&
3964 (au->advertised || allow_auth_unadvertised))
3969 c = smtp_in_auth(au, &s, &ss);
3971 smtp_printf("%s\r\n", FALSE, s);
3973 log_write(0, LOG_MAIN|LOG_REJECT, "%s authenticator failed for %s: %s",
3974 au->name, host_and_ident(FALSE), ss);
3977 done = synprot_error(L_smtp_protocol_error, 504, NULL,
3978 string_sprintf("%s authentication mechanism not supported", s));
3980 break; /* AUTH_CMD */
3982 /* The HELO/EHLO commands are permitted to appear in the middle of a
3983 session as well as at the beginning. They have the effect of a reset in
3984 addition to their other functions. Their absence at the start cannot be
3985 taken to be an error.
3989 If the EHLO command is not acceptable to the SMTP server, 501, 500,
3990 or 502 failure replies MUST be returned as appropriate. The SMTP
3991 server MUST stay in the same state after transmitting these replies
3992 that it was in before the EHLO was received.
3994 Therefore, we do not do the reset until after checking the command for
3995 acceptability. This change was made for Exim release 4.11. Previously
3996 it did the reset first. */
4009 HELO_EHLO: /* Common code for HELO and EHLO */
4010 cmd_list[CMD_LIST_HELO].is_mail_cmd = FALSE;
4011 cmd_list[CMD_LIST_EHLO].is_mail_cmd = FALSE;
4013 /* Reject the HELO if its argument was invalid or non-existent. A
4014 successful check causes the argument to be saved in malloc store. */
4016 if (!check_helo(smtp_cmd_data))
4018 smtp_printf("501 Syntactically invalid %s argument(s)\r\n", FALSE, hello);
4020 log_write(0, LOG_MAIN|LOG_REJECT, "rejected %s from %s: syntactically "
4021 "invalid argument(s): %s", hello, host_and_ident(FALSE),
4022 (*smtp_cmd_argument == 0)? US"(no argument given)" :
4023 string_printing(smtp_cmd_argument));
4025 if (++synprot_error_count > smtp_max_synprot_errors)
4027 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
4028 "syntax or protocol errors (last command was \"%s\")",
4029 host_and_ident(FALSE), string_printing(smtp_cmd_buffer));
4036 /* If sender_host_unknown is true, we have got here via the -bs interface,
4037 not called from inetd. Otherwise, we are running an IP connection and the
4038 host address will be set. If the helo name is the primary name of this
4039 host and we haven't done a reverse lookup, force one now. If helo_required
4040 is set, ensure that the HELO name matches the actual host. If helo_verify
4041 is set, do the same check, but softly. */
4043 if (!sender_host_unknown)
4045 BOOL old_helo_verified = helo_verified;
4046 uschar *p = smtp_cmd_data;
4048 while (*p != 0 && !isspace(*p)) { *p = tolower(*p); p++; }
4051 /* Force a reverse lookup if HELO quoted something in helo_lookup_domains
4052 because otherwise the log can be confusing. */
4054 if ( !sender_host_name
4055 && (deliver_domain = sender_helo_name, /* set $domain */
4056 match_isinlist(sender_helo_name, CUSS &helo_lookup_domains, 0,
4057 &domainlist_anchor, NULL, MCL_DOMAIN, TRUE, NULL)) == OK)
4058 (void)host_name_lookup();
4060 /* Rebuild the fullhost info to include the HELO name (and the real name
4061 if it was looked up.) */
4063 host_build_sender_fullhost(); /* Rebuild */
4064 set_process_info("handling%s incoming connection from %s",
4065 (tls_in.active >= 0)? " TLS" : "", host_and_ident(FALSE));
4067 /* Verify if configured. This doesn't give much security, but it does
4068 make some people happy to be able to do it. If helo_required is set,
4069 (host matches helo_verify_hosts) failure forces rejection. If helo_verify
4070 is set (host matches helo_try_verify_hosts), it does not. This is perhaps
4071 now obsolescent, since the verification can now be requested selectively
4074 helo_verified = helo_verify_failed = sender_helo_dnssec = FALSE;
4075 if (helo_required || helo_verify)
4077 BOOL tempfail = !smtp_verify_helo();
4082 smtp_printf("%d %s argument does not match calling host\r\n", FALSE,
4083 tempfail? 451 : 550, hello);
4084 log_write(0, LOG_MAIN|LOG_REJECT, "%srejected \"%s %s\" from %s",
4085 tempfail? "temporarily " : "",
4086 hello, sender_helo_name, host_and_ident(FALSE));
4087 helo_verified = old_helo_verified;
4088 break; /* End of HELO/EHLO processing */
4090 HDEBUG(D_all) debug_printf("%s verification failed but host is in "
4091 "helo_try_verify_hosts\n", hello);
4097 /* set up SPF context */
4098 spf_init(sender_helo_name, sender_host_address);
4101 /* Apply an ACL check if one is defined; afterwards, recheck
4102 synchronization in case the client started sending in a delay. */
4105 if ((rc = acl_check(ACL_WHERE_HELO, NULL, acl_smtp_helo,
4106 &user_msg, &log_msg)) != OK)
4108 done = smtp_handle_acl_fail(ACL_WHERE_HELO, rc, user_msg, log_msg);
4109 if (sender_helo_name)
4111 store_free(sender_helo_name);
4112 sender_helo_name = NULL;
4114 host_build_sender_fullhost(); /* Rebuild */
4117 else if (!check_sync()) goto SYNC_FAILURE;
4119 /* Generate an OK reply. The default string includes the ident if present,
4120 and also the IP address if present. Reflecting back the ident is intended
4121 as a deterrent to mail forgers. For maximum efficiency, and also because
4122 some broken systems expect each response to be in a single packet, arrange
4123 that the entire reply is sent in one write(). */
4125 auth_advertised = FALSE;
4126 pipelining_advertised = FALSE;
4128 tls_advertised = FALSE;
4130 dsn_advertised = FALSE;
4132 smtputf8_advertised = FALSE;
4135 smtp_code = US"250 "; /* Default response code plus space*/
4138 s = string_sprintf("%.3s %s Hello %s%s%s",
4140 smtp_active_hostname,
4141 sender_ident ? sender_ident : US"",
4142 sender_ident ? US" at " : US"",
4143 sender_host_name ? sender_host_name : sender_helo_name);
4144 g = string_cat(NULL, s);
4146 if (sender_host_address)
4148 g = string_catn(g, US" [", 2);
4149 g = string_cat (g, sender_host_address);
4150 g = string_catn(g, US"]", 1);
4154 /* A user-supplied EHLO greeting may not contain more than one line. Note
4155 that the code returned by smtp_message_code() includes the terminating
4156 whitespace character. */
4162 smtp_message_code(&smtp_code, &codelen, &user_msg, NULL, TRUE);
4163 s = string_sprintf("%.*s%s", codelen, smtp_code, user_msg);
4164 if ((ss = strpbrk(CS s, "\r\n")) != NULL)
4166 log_write(0, LOG_MAIN|LOG_PANIC, "EHLO/HELO response must not contain "
4167 "newlines: message truncated: %s", string_printing(s));
4170 g = string_cat(NULL, s);
4173 g = string_catn(g, US"\r\n", 2);
4175 /* If we received EHLO, we must create a multiline response which includes
4176 the functions supported. */
4182 /* I'm not entirely happy with this, as an MTA is supposed to check
4183 that it has enough room to accept a message of maximum size before
4184 it sends this. However, there seems little point in not sending it.
4185 The actual size check happens later at MAIL FROM time. By postponing it
4186 till then, VRFY and EXPN can be used after EHLO when space is short. */
4188 if (thismessage_size_limit > 0)
4190 sprintf(CS big_buffer, "%.3s-SIZE %d\r\n", smtp_code,
4191 thismessage_size_limit);
4192 g = string_cat(g, big_buffer);
4196 g = string_catn(g, smtp_code, 3);
4197 g = string_catn(g, US"-SIZE\r\n", 7);
4200 /* Exim does not do protocol conversion or data conversion. It is 8-bit
4201 clean; if it has an 8-bit character in its hand, it just sends it. It
4202 cannot therefore specify 8BITMIME and remain consistent with the RFCs.
4203 However, some users want this option simply in order to stop MUAs
4204 mangling messages that contain top-bit-set characters. It is therefore
4205 provided as an option. */
4207 if (accept_8bitmime)
4209 g = string_catn(g, smtp_code, 3);
4210 g = string_catn(g, US"-8BITMIME\r\n", 11);
4213 /* Advertise DSN support if configured to do so. */
4214 if (verify_check_host(&dsn_advertise_hosts) != FAIL)
4216 g = string_catn(g, smtp_code, 3);
4217 g = string_catn(g, US"-DSN\r\n", 6);
4218 dsn_advertised = TRUE;
4221 /* Advertise ETRN/VRFY/EXPN if there's are ACL checking whether a host is
4222 permitted to issue them; a check is made when any host actually tries. */
4226 g = string_catn(g, smtp_code, 3);
4227 g = string_catn(g, US"-ETRN\r\n", 7);
4231 g = string_catn(g, smtp_code, 3);
4232 g = string_catn(g, US"-VRFY\r\n", 7);
4236 g = string_catn(g, smtp_code, 3);
4237 g = string_catn(g, US"-EXPN\r\n", 7);
4240 /* Exim is quite happy with pipelining, so let the other end know that
4241 it is safe to use it, unless advertising is disabled. */
4243 if (pipelining_enable &&
4244 verify_check_host(&pipelining_advertise_hosts) == OK)
4246 g = string_catn(g, smtp_code, 3);
4247 g = string_catn(g, US"-PIPELINING\r\n", 13);
4248 sync_cmd_limit = NON_SYNC_CMD_PIPELINING;
4249 pipelining_advertised = TRUE;
4253 /* If any server authentication mechanisms are configured, advertise
4254 them if the current host is in auth_advertise_hosts. The problem with
4255 advertising always is that some clients then require users to
4256 authenticate (and aren't configurable otherwise) even though it may not
4257 be necessary (e.g. if the host is in host_accept_relay).
4259 RFC 2222 states that SASL mechanism names contain only upper case
4260 letters, so output the names in upper case, though we actually recognize
4261 them in either case in the AUTH command. */
4265 && !sender_host_authenticated
4267 && verify_check_host(&auth_advertise_hosts) == OK
4272 for (au = auths; au; au = au->next)
4274 au->advertised = FALSE;
4277 DEBUG(D_auth+D_expand) debug_printf_indent(
4278 "Evaluating advertise_condition for %s athenticator\n",
4280 if ( !au->advertise_condition
4281 || expand_check_condition(au->advertise_condition, au->name,
4288 g = string_catn(g, smtp_code, 3);
4289 g = string_catn(g, US"-AUTH", 5);
4291 auth_advertised = TRUE;
4294 g = string_catn(g, US" ", 1);
4295 g = string_cat (g, au->public_name);
4296 while (++saveptr < g->ptr) g->s[saveptr] = toupper(g->s[saveptr]);
4297 au->advertised = TRUE;
4302 if (!first) g = string_catn(g, US"\r\n", 2);
4305 /* RFC 3030 CHUNKING */
4307 if (verify_check_host(&chunking_advertise_hosts) != FAIL)
4309 g = string_catn(g, smtp_code, 3);
4310 g = string_catn(g, US"-CHUNKING\r\n", 11);
4311 chunking_offered = TRUE;
4312 chunking_state = CHUNKING_OFFERED;
4315 /* Advertise TLS (Transport Level Security) aka SSL (Secure Socket Layer)
4316 if it has been included in the binary, and the host matches
4317 tls_advertise_hosts. We must *not* advertise if we are already in a
4318 secure connection. */
4321 if (tls_in.active < 0 &&
4322 verify_check_host(&tls_advertise_hosts) != FAIL)
4324 g = string_catn(g, smtp_code, 3);
4325 g = string_catn(g, US"-STARTTLS\r\n", 11);
4326 tls_advertised = TRUE;
4330 #ifndef DISABLE_PRDR
4331 /* Per Recipient Data Response, draft by Eric A. Hall extending RFC */
4334 g = string_catn(g, smtp_code, 3);
4335 g = string_catn(g, US"-PRDR\r\n", 7);
4340 if ( accept_8bitmime
4341 && verify_check_host(&smtputf8_advertise_hosts) != FAIL)
4343 g = string_catn(g, smtp_code, 3);
4344 g = string_catn(g, US"-SMTPUTF8\r\n", 11);
4345 smtputf8_advertised = TRUE;
4349 /* Finish off the multiline reply with one that is always available. */
4351 g = string_catn(g, smtp_code, 3);
4352 g = string_catn(g, US" HELP\r\n", 7);
4355 /* Terminate the string (for debug), write it, and note that HELO/EHLO
4359 if (tls_in.active >= 0) (void)tls_write(TRUE, g->s, g->ptr, FALSE); else
4363 int i = fwrite(g->s, 1, g->ptr, smtp_out); i = i; /* compiler quietening */
4369 (void) string_from_gstring(g);
4370 while ((cr = Ustrchr(g->s, '\r')) != NULL) /* lose CRs */
4371 memmove(cr, cr + 1, (g->ptr--) - (cr - g->s));
4372 debug_printf("SMTP>> %s", g->s);
4376 /* Reset the protocol and the state, abandoning any previous message. */
4378 (sender_host_address ? protocols : protocols_local)
4380 ? pextend + (sender_host_authenticated ? pauthed : 0)
4382 + (tls_in.active >= 0 ? pcrpted : 0)
4384 cancel_cutthrough_connection(TRUE, US"sent EHLO response");
4385 smtp_reset(reset_point);
4387 break; /* HELO/EHLO */
4390 /* The MAIL command requires an address as an operand. All we do
4391 here is to parse it for syntactic correctness. The form "<>" is
4392 a special case which converts into an empty string. The start/end
4393 pointers in the original are not used further for this address, as
4394 it is the canonical extracted address which is all that is kept. */
4398 smtp_mailcmd_count++; /* Count for limit and ratelimit */
4399 was_rej_mail = TRUE; /* Reset if accepted */
4400 env_mail_type_t * mail_args; /* Sanity check & validate args */
4402 if (helo_required && !helo_seen)
4404 smtp_printf("503 HELO or EHLO required\r\n", FALSE);
4405 log_write(0, LOG_MAIN|LOG_REJECT, "rejected MAIL from %s: no "
4406 "HELO/EHLO given", host_and_ident(FALSE));
4410 if (sender_address != NULL)
4412 done = synprot_error(L_smtp_protocol_error, 503, NULL,
4413 US"sender already given");
4417 if (smtp_cmd_data[0] == 0)
4419 done = synprot_error(L_smtp_protocol_error, 501, NULL,
4420 US"MAIL must have an address operand");
4424 /* Check to see if the limit for messages per connection would be
4425 exceeded by accepting further messages. */
4427 if (smtp_accept_max_per_connection > 0 &&
4428 smtp_mailcmd_count > smtp_accept_max_per_connection)
4430 smtp_printf("421 too many messages in this connection\r\n", FALSE);
4431 log_write(0, LOG_MAIN|LOG_REJECT, "rejected MAIL command %s: too many "
4432 "messages in one connection", host_and_ident(TRUE));
4436 /* Reset for start of message - even if this is going to fail, we
4437 obviously need to throw away any previous data. */
4439 cancel_cutthrough_connection(TRUE, US"MAIL received");
4440 smtp_reset(reset_point);
4442 sender_data = recipient_data = NULL;
4444 /* Loop, checking for ESMTP additions to the MAIL FROM command. */
4448 uschar *name, *value, *end;
4449 unsigned long int size;
4450 BOOL arg_error = FALSE;
4452 if (!extract_option(&name, &value)) break;
4454 for (mail_args = env_mail_type_list;
4455 mail_args->value != ENV_MAIL_OPT_NULL;
4458 if (strcmpic(name, mail_args->name) == 0)
4460 if (mail_args->need_value && strcmpic(value, US"") == 0)
4463 switch(mail_args->value)
4465 /* Handle SIZE= by reading the value. We don't do the check till later,
4466 in order to be able to log the sender address on failure. */
4467 case ENV_MAIL_OPT_SIZE:
4468 if (((size = Ustrtoul(value, &end, 10)), *end == 0))
4470 if ((size == ULONG_MAX && errno == ERANGE) || size > INT_MAX)
4472 message_size = (int)size;
4478 /* If this session was initiated with EHLO and accept_8bitmime is set,
4479 Exim will have indicated that it supports the BODY=8BITMIME option. In
4480 fact, it does not support this according to the RFCs, in that it does not
4481 take any special action for forwarding messages containing 8-bit
4482 characters. That is why accept_8bitmime is not the default setting, but
4483 some sites want the action that is provided. We recognize both "8BITMIME"
4484 and "7BIT" as body types, but take no action. */
4485 case ENV_MAIL_OPT_BODY:
4486 if (accept_8bitmime) {
4487 if (strcmpic(value, US"8BITMIME") == 0)
4489 else if (strcmpic(value, US"7BIT") == 0)
4494 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4495 US"invalid data for BODY");
4498 DEBUG(D_receive) debug_printf("8BITMIME: %d\n", body_8bitmime);
4504 /* Handle the two DSN options, but only if configured to do so (which
4505 will have caused "DSN" to be given in the EHLO response). The code itself
4506 is included only if configured in at build time. */
4508 case ENV_MAIL_OPT_RET:
4511 /* Check if RET has already been set */
4514 synprot_error(L_smtp_syntax_error, 501, NULL,
4515 US"RET can be specified once only");
4518 dsn_ret = strcmpic(value, US"HDRS") == 0
4520 : strcmpic(value, US"FULL") == 0
4523 DEBUG(D_receive) debug_printf("DSN_RET: %d\n", dsn_ret);
4524 /* Check for invalid invalid value, and exit with error */
4527 synprot_error(L_smtp_syntax_error, 501, NULL,
4528 US"Value for RET is invalid");
4533 case ENV_MAIL_OPT_ENVID:
4536 /* Check if the dsn envid has been already set */
4537 if (dsn_envid != NULL)
4539 synprot_error(L_smtp_syntax_error, 501, NULL,
4540 US"ENVID can be specified once only");
4543 dsn_envid = string_copy(value);
4544 DEBUG(D_receive) debug_printf("DSN_ENVID: %s\n", dsn_envid);
4548 /* Handle the AUTH extension. If the value given is not "<>" and either
4549 the ACL says "yes" or there is no ACL but the sending host is
4550 authenticated, we set it up as the authenticated sender. However, if the
4551 authenticator set a condition to be tested, we ignore AUTH on MAIL unless
4552 the condition is met. The value of AUTH is an xtext, which means that +,
4553 = and cntrl chars are coded in hex; however "<>" is unaffected by this
4555 case ENV_MAIL_OPT_AUTH:
4556 if (Ustrcmp(value, "<>") != 0)
4561 if (auth_xtextdecode(value, &authenticated_sender) < 0)
4563 /* Put back terminator overrides for error message */
4566 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4567 US"invalid data for AUTH");
4570 if (!acl_smtp_mailauth)
4572 ignore_msg = US"client not authenticated";
4573 rc = sender_host_authenticated ? OK : FAIL;
4577 ignore_msg = US"rejected by ACL";
4578 rc = acl_check(ACL_WHERE_MAILAUTH, NULL, acl_smtp_mailauth,
4579 &user_msg, &log_msg);
4585 if (authenticated_by == NULL ||
4586 authenticated_by->mail_auth_condition == NULL ||
4587 expand_check_condition(authenticated_by->mail_auth_condition,
4588 authenticated_by->name, US"authenticator"))
4589 break; /* Accept the AUTH */
4591 ignore_msg = US"server_mail_auth_condition failed";
4592 if (authenticated_id != NULL)
4593 ignore_msg = string_sprintf("%s: authenticated ID=\"%s\"",
4594 ignore_msg, authenticated_id);
4599 authenticated_sender = NULL;
4600 log_write(0, LOG_MAIN, "ignoring AUTH=%s from %s (%s)",
4601 value, host_and_ident(TRUE), ignore_msg);
4604 /* Should only get DEFER or ERROR here. Put back terminator
4605 overrides for error message */
4610 (void)smtp_handle_acl_fail(ACL_WHERE_MAILAUTH, rc, user_msg,
4617 #ifndef DISABLE_PRDR
4618 case ENV_MAIL_OPT_PRDR:
4620 prdr_requested = TRUE;
4625 case ENV_MAIL_OPT_UTF8:
4626 if (smtputf8_advertised)
4628 int old_pool = store_pool;
4630 DEBUG(D_receive) debug_printf("smtputf8 requested\n");
4631 message_smtputf8 = allow_utf8_domains = TRUE;
4632 store_pool = POOL_PERM;
4633 received_protocol = string_sprintf("utf8%s", received_protocol);
4634 store_pool = old_pool;
4638 /* No valid option. Stick back the terminator characters and break
4639 the loop. Do the name-terminator second as extract_option sets
4640 value==name when it found no equal-sign.
4641 An error for a malformed address will occur. */
4642 case ENV_MAIL_OPT_NULL:
4650 /* Break out of for loop if switch() had bad argument or
4651 when start of the email address is reached */
4652 if (arg_error) break;
4655 /* If we have passed the threshold for rate limiting, apply the current
4656 delay, and update it for next time, provided this is a limited host. */
4658 if (smtp_mailcmd_count > smtp_rlm_threshold &&
4659 verify_check_host(&smtp_ratelimit_hosts) == OK)
4661 DEBUG(D_receive) debug_printf("rate limit MAIL: delay %.3g sec\n",
4662 smtp_delay_mail/1000.0);
4663 millisleep((int)smtp_delay_mail);
4664 smtp_delay_mail *= smtp_rlm_factor;
4665 if (smtp_delay_mail > (double)smtp_rlm_limit)
4666 smtp_delay_mail = (double)smtp_rlm_limit;
4669 /* Now extract the address, first applying any SMTP-time rewriting. The
4670 TRUE flag allows "<>" as a sender address. */
4672 raw_sender = rewrite_existflags & rewrite_smtp
4673 ? rewrite_one(smtp_cmd_data, rewrite_smtp, NULL, FALSE, US"",
4674 global_rewrite_rules)
4678 parse_extract_address(raw_sender, &errmess, &start, &end, &sender_domain,
4683 done = synprot_error(L_smtp_syntax_error, 501, smtp_cmd_data, errmess);
4687 sender_address = raw_sender;
4689 /* If there is a configured size limit for mail, check that this message
4690 doesn't exceed it. The check is postponed to this point so that the sender
4693 if (thismessage_size_limit > 0 && message_size > thismessage_size_limit)
4695 smtp_printf("552 Message size exceeds maximum permitted\r\n", FALSE);
4696 log_write(L_size_reject,
4697 LOG_MAIN|LOG_REJECT, "rejected MAIL FROM:<%s> %s: "
4698 "message too big: size%s=%d max=%d",
4700 host_and_ident(TRUE),
4701 (message_size == INT_MAX)? ">" : "",
4703 thismessage_size_limit);
4704 sender_address = NULL;
4708 /* Check there is enough space on the disk unless configured not to.
4709 When smtp_check_spool_space is set, the check is for thismessage_size_limit
4710 plus the current message - i.e. we accept the message only if it won't
4711 reduce the space below the threshold. Add 5000 to the size to allow for
4712 overheads such as the Received: line and storing of recipients, etc.
4713 By putting the check here, even when SIZE is not given, it allow VRFY
4714 and EXPN etc. to be used when space is short. */
4716 if (!receive_check_fs(
4717 (smtp_check_spool_space && message_size >= 0)?
4718 message_size + 5000 : 0))
4720 smtp_printf("452 Space shortage, please try later\r\n", FALSE);
4721 sender_address = NULL;
4725 /* If sender_address is unqualified, reject it, unless this is a locally
4726 generated message, or the sending host or net is permitted to send
4727 unqualified addresses - typically local machines behaving as MUAs -
4728 in which case just qualify the address. The flag is set above at the start
4729 of the SMTP connection. */
4731 if (sender_domain == 0 && sender_address[0] != 0)
4733 if (allow_unqualified_sender)
4735 sender_domain = Ustrlen(sender_address) + 1;
4736 sender_address = rewrite_address_qualify(sender_address, FALSE);
4737 DEBUG(D_receive) debug_printf("unqualified address %s accepted\n",
4742 smtp_printf("501 %s: sender address must contain a domain\r\n", FALSE,
4744 log_write(L_smtp_syntax_error,
4745 LOG_MAIN|LOG_REJECT,
4746 "unqualified sender rejected: <%s> %s%s",
4748 host_and_ident(TRUE),
4750 sender_address = NULL;
4755 /* Apply an ACL check if one is defined, before responding. Afterwards,
4756 when pipelining is not advertised, do another sync check in case the ACL
4757 delayed and the client started sending in the meantime. */
4761 rc = acl_check(ACL_WHERE_MAIL, NULL, acl_smtp_mail, &user_msg, &log_msg);
4762 if (rc == OK && !pipelining_advertised && !check_sync())
4768 if (rc == OK || rc == DISCARD)
4770 BOOL more = pipeline_response();
4773 smtp_printf("%s%s%s", more, US"250 OK",
4774 #ifndef DISABLE_PRDR
4775 prdr_requested ? US", PRDR Requested" : US"",
4782 #ifndef DISABLE_PRDR
4784 user_msg = string_sprintf("%s%s", user_msg, US", PRDR Requested");
4786 smtp_user_msg(US"250", user_msg);
4788 smtp_delay_rcpt = smtp_rlr_base;
4789 recipients_discarded = (rc == DISCARD);
4790 was_rej_mail = FALSE;
4794 done = smtp_handle_acl_fail(ACL_WHERE_MAIL, rc, user_msg, log_msg);
4795 sender_address = NULL;
4800 /* The RCPT command requires an address as an operand. There may be any
4801 number of RCPT commands, specifying multiple recipients. We build them all
4802 into a data structure. The start/end values given by parse_extract_address
4803 are not used, as we keep only the extracted address. */
4808 was_rcpt = rcpt_in_progress = TRUE;
4810 /* There must be a sender address; if the sender was rejected and
4811 pipelining was advertised, we assume the client was pipelining, and do not
4812 count this as a protocol error. Reset was_rej_mail so that further RCPTs
4813 get the same treatment. */
4815 if (sender_address == NULL)
4817 if (pipelining_advertised && last_was_rej_mail)
4819 smtp_printf("503 sender not yet given\r\n", FALSE);
4820 was_rej_mail = TRUE;
4824 done = synprot_error(L_smtp_protocol_error, 503, NULL,
4825 US"sender not yet given");
4826 was_rcpt = FALSE; /* Not a valid RCPT */
4832 /* Check for an operand */
4834 if (smtp_cmd_data[0] == 0)
4836 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4837 US"RCPT must have an address operand");
4842 /* Set the DSN flags orcpt and dsn_flags from the session*/
4848 uschar *name, *value;
4850 if (!extract_option(&name, &value))
4853 if (dsn_advertised && strcmpic(name, US"ORCPT") == 0)
4855 /* Check whether orcpt has been already set */
4858 synprot_error(L_smtp_syntax_error, 501, NULL,
4859 US"ORCPT can be specified once only");
4862 orcpt = string_copy(value);
4863 DEBUG(D_receive) debug_printf("DSN orcpt: %s\n", orcpt);
4866 else if (dsn_advertised && strcmpic(name, US"NOTIFY") == 0)
4868 /* Check if the notify flags have been already set */
4871 synprot_error(L_smtp_syntax_error, 501, NULL,
4872 US"NOTIFY can be specified once only");
4875 if (strcmpic(value, US"NEVER") == 0)
4876 flags |= rf_notify_never;
4883 while (*pp != 0 && *pp != ',') pp++;
4884 if (*pp == ',') *pp++ = 0;
4885 if (strcmpic(p, US"SUCCESS") == 0)
4887 DEBUG(D_receive) debug_printf("DSN: Setting notify success\n");
4888 flags |= rf_notify_success;
4890 else if (strcmpic(p, US"FAILURE") == 0)
4892 DEBUG(D_receive) debug_printf("DSN: Setting notify failure\n");
4893 flags |= rf_notify_failure;
4895 else if (strcmpic(p, US"DELAY") == 0)
4897 DEBUG(D_receive) debug_printf("DSN: Setting notify delay\n");
4898 flags |= rf_notify_delay;
4902 /* Catch any strange values */
4903 synprot_error(L_smtp_syntax_error, 501, NULL,
4904 US"Invalid value for NOTIFY parameter");
4909 DEBUG(D_receive) debug_printf("DSN Flags: %x\n", flags);
4913 /* Unknown option. Stick back the terminator characters and break
4914 the loop. An error for a malformed address will occur. */
4918 DEBUG(D_receive) debug_printf("Invalid RCPT option: %s : %s\n", name, value);
4925 /* Apply SMTP rewriting then extract the working address. Don't allow "<>"
4926 as a recipient address */
4928 recipient = rewrite_existflags & rewrite_smtp
4929 ? rewrite_one(smtp_cmd_data, rewrite_smtp, NULL, FALSE, US"",
4930 global_rewrite_rules)
4933 if (!(recipient = parse_extract_address(recipient, &errmess, &start, &end,
4934 &recipient_domain, FALSE)))
4936 done = synprot_error(L_smtp_syntax_error, 501, smtp_cmd_data, errmess);
4941 /* If the recipient address is unqualified, reject it, unless this is a
4942 locally generated message. However, unqualified addresses are permitted
4943 from a configured list of hosts and nets - typically when behaving as
4944 MUAs rather than MTAs. Sad that SMTP is used for both types of traffic,
4945 really. The flag is set at the start of the SMTP connection.
4947 RFC 1123 talks about supporting "the reserved mailbox postmaster"; I always
4948 assumed this meant "reserved local part", but the revision of RFC 821 and
4949 friends now makes it absolutely clear that it means *mailbox*. Consequently
4950 we must always qualify this address, regardless. */
4952 if (!recipient_domain)
4953 if (!(recipient_domain = qualify_recipient(&recipient, smtp_cmd_data,
4960 /* Check maximum allowed */
4962 if (rcpt_count > recipients_max && recipients_max > 0)
4964 if (recipients_max_reject)
4967 smtp_printf("552 too many recipients\r\n", FALSE);
4969 log_write(0, LOG_MAIN|LOG_REJECT, "too many recipients: message "
4970 "rejected: sender=<%s> %s", sender_address, host_and_ident(TRUE));
4975 smtp_printf("452 too many recipients\r\n", FALSE);
4977 log_write(0, LOG_MAIN|LOG_REJECT, "too many recipients: excess "
4978 "temporarily rejected: sender=<%s> %s", sender_address,
4979 host_and_ident(TRUE));
4986 /* If we have passed the threshold for rate limiting, apply the current
4987 delay, and update it for next time, provided this is a limited host. */
4989 if (rcpt_count > smtp_rlr_threshold &&
4990 verify_check_host(&smtp_ratelimit_hosts) == OK)
4992 DEBUG(D_receive) debug_printf("rate limit RCPT: delay %.3g sec\n",
4993 smtp_delay_rcpt/1000.0);
4994 millisleep((int)smtp_delay_rcpt);
4995 smtp_delay_rcpt *= smtp_rlr_factor;
4996 if (smtp_delay_rcpt > (double)smtp_rlr_limit)
4997 smtp_delay_rcpt = (double)smtp_rlr_limit;
5000 /* If the MAIL ACL discarded all the recipients, we bypass ACL checking
5001 for them. Otherwise, check the access control list for this recipient. As
5002 there may be a delay in this, re-check for a synchronization error
5003 afterwards, unless pipelining was advertised. */
5005 if (recipients_discarded)
5008 if ( (rc = acl_check(ACL_WHERE_RCPT, recipient, acl_smtp_rcpt, &user_msg,
5010 && !pipelining_advertised && !check_sync())
5013 /* The ACL was happy */
5017 BOOL more = pipeline_response();
5020 smtp_user_msg(US"250", user_msg);
5022 smtp_printf("250 Accepted\r\n", more);
5023 receive_add_recipient(recipient, -1);
5025 /* Set the dsn flags in the recipients_list */
5026 recipients_list[recipients_count-1].orcpt = orcpt;
5027 recipients_list[recipients_count-1].dsn_flags = flags;
5029 DEBUG(D_receive) debug_printf("DSN: orcpt: %s flags: %d\n",
5030 recipients_list[recipients_count-1].orcpt,
5031 recipients_list[recipients_count-1].dsn_flags);
5034 /* The recipient was discarded */
5036 else if (rc == DISCARD)
5039 smtp_user_msg(US"250", user_msg);
5041 smtp_printf("250 Accepted\r\n", FALSE);
5044 log_write(0, LOG_MAIN|LOG_REJECT, "%s F=<%s> RCPT %s: "
5045 "discarded by %s ACL%s%s", host_and_ident(TRUE),
5046 sender_address_unrewritten? sender_address_unrewritten : sender_address,
5047 smtp_cmd_argument, recipients_discarded? "MAIL" : "RCPT",
5048 log_msg ? US": " : US"", log_msg ? log_msg : US"");
5051 /* Either the ACL failed the address, or it was deferred. */
5055 if (rc == FAIL) rcpt_fail_count++; else rcpt_defer_count++;
5056 done = smtp_handle_acl_fail(ACL_WHERE_RCPT, rc, user_msg, log_msg);
5061 /* The DATA command is legal only if it follows successful MAIL FROM
5062 and RCPT TO commands. However, if pipelining is advertised, a bad DATA is
5063 not counted as a protocol error if it follows RCPT (which must have been
5064 rejected if there are no recipients.) This function is complete when a
5065 valid DATA command is encountered.
5067 Note concerning the code used: RFC 2821 says this:
5069 - If there was no MAIL, or no RCPT, command, or all such commands
5070 were rejected, the server MAY return a "command out of sequence"
5071 (503) or "no valid recipients" (554) reply in response to the
5074 The example in the pipelining RFC 2920 uses 554, but I use 503 here
5075 because it is the same whether pipelining is in use or not.
5077 If all the RCPT commands that precede DATA provoked the same error message
5078 (often indicating some kind of system error), it is helpful to include it
5079 with the DATA rejection (an idea suggested by Tony Finch). */
5086 if (chunking_state != CHUNKING_OFFERED)
5088 done = synprot_error(L_smtp_protocol_error, 503, NULL,
5089 US"BDAT command used when CHUNKING not advertised");
5093 /* grab size, endmarker */
5095 if (sscanf(CS smtp_cmd_data, "%u %n", &chunking_datasize, &n) < 1)
5097 done = synprot_error(L_smtp_protocol_error, 501, NULL,
5098 US"missing size for BDAT command");
5101 chunking_state = strcmpic(smtp_cmd_data+n, US"LAST") == 0
5102 ? CHUNKING_LAST : CHUNKING_ACTIVE;
5103 chunking_data_left = chunking_datasize;
5104 DEBUG(D_receive) debug_printf("chunking state %d, %d bytes\n",
5105 (int)chunking_state, chunking_data_left);
5107 /* push the current receive_* function on the "stack", and
5108 replace them by bdat_getc(), which in turn will use the lwr_receive_*
5109 functions to do the dirty work. */
5110 lwr_receive_getc = receive_getc;
5111 lwr_receive_getbuf = receive_getbuf;
5112 lwr_receive_ungetc = receive_ungetc;
5114 receive_getc = bdat_getc;
5115 receive_ungetc = bdat_ungetc;
5126 DATA_BDAT: /* Common code for DATA and BDAT */
5127 if (!discarded && recipients_count <= 0)
5129 if (rcpt_smtp_response_same && rcpt_smtp_response != NULL)
5131 uschar *code = US"503";
5132 int len = Ustrlen(rcpt_smtp_response);
5133 smtp_respond(code, 3, FALSE, US"All RCPT commands were rejected with "
5135 /* Responses from smtp_printf() will have \r\n on the end */
5136 if (len > 2 && rcpt_smtp_response[len-2] == '\r')
5137 rcpt_smtp_response[len-2] = 0;
5138 smtp_respond(code, 3, FALSE, rcpt_smtp_response);
5140 if (pipelining_advertised && last_was_rcpt)
5141 smtp_printf("503 Valid RCPT command must precede %s\r\n", FALSE,
5142 smtp_names[smtp_connection_had[smtp_ch_index-1]]);
5144 done = synprot_error(L_smtp_protocol_error, 503, NULL,
5145 smtp_connection_had[smtp_ch_index-1] == SCH_DATA
5146 ? US"valid RCPT command must precede DATA"
5147 : US"valid RCPT command must precede BDAT");
5149 if (chunking_state > CHUNKING_OFFERED)
5154 if (toomany && recipients_max_reject)
5156 sender_address = NULL; /* This will allow a new MAIL without RSET */
5157 sender_address_unrewritten = NULL;
5158 smtp_printf("554 Too many recipients\r\n", FALSE);
5162 if (chunking_state > CHUNKING_OFFERED)
5163 rc = OK; /* No predata ACL or go-ahead output for BDAT */
5166 /* If there is an ACL, re-check the synchronization afterwards, since the
5167 ACL may have delayed. To handle cutthrough delivery enforce a dummy call
5168 to get the DATA command sent. */
5170 if (acl_smtp_predata == NULL && cutthrough.fd < 0)
5174 uschar * acl = acl_smtp_predata ? acl_smtp_predata : US"accept";
5175 enable_dollar_recipients = TRUE;
5176 rc = acl_check(ACL_WHERE_PREDATA, NULL, acl, &user_msg,
5178 enable_dollar_recipients = FALSE;
5179 if (rc == OK && !check_sync())
5183 { /* Either the ACL failed the address, or it was deferred. */
5184 done = smtp_handle_acl_fail(ACL_WHERE_PREDATA, rc, user_msg, log_msg);
5190 smtp_user_msg(US"354", user_msg);
5193 "354 Enter message, ending with \".\" on a line by itself\r\n", FALSE);
5197 if (smtp_in) /* all ACKs needed to ramp window up for bulk data */
5198 (void) setsockopt(fileno(smtp_in), IPPROTO_TCP, TCP_QUICKACK,
5199 US &on, sizeof(on));
5202 message_ended = END_NOTENDED; /* Indicate in middle of data */
5213 if (!(address = parse_extract_address(smtp_cmd_data, &errmess,
5214 &start, &end, &recipient_domain, FALSE)))
5216 smtp_printf("501 %s\r\n", FALSE, errmess);
5220 if (!recipient_domain)
5221 if (!(recipient_domain = qualify_recipient(&address, smtp_cmd_data,
5225 if ((rc = acl_check(ACL_WHERE_VRFY, address, acl_smtp_vrfy,
5226 &user_msg, &log_msg)) != OK)
5227 done = smtp_handle_acl_fail(ACL_WHERE_VRFY, rc, user_msg, log_msg);
5231 address_item * addr = deliver_make_addr(address, FALSE);
5233 switch(verify_address(addr, NULL, vopt_is_recipient | vopt_qualify, -1,
5234 -1, -1, NULL, NULL, NULL))
5237 s = string_sprintf("250 <%s> is deliverable", address);
5241 s = (addr->user_message != NULL)?
5242 string_sprintf("451 <%s> %s", address, addr->user_message) :
5243 string_sprintf("451 Cannot resolve <%s> at this time", address);
5247 s = (addr->user_message != NULL)?
5248 string_sprintf("550 <%s> %s", address, addr->user_message) :
5249 string_sprintf("550 <%s> is not deliverable", address);
5250 log_write(0, LOG_MAIN, "VRFY failed for %s %s",
5251 smtp_cmd_argument, host_and_ident(TRUE));
5255 smtp_printf("%s\r\n", FALSE, s);
5263 rc = acl_check(ACL_WHERE_EXPN, NULL, acl_smtp_expn, &user_msg, &log_msg);
5265 done = smtp_handle_acl_fail(ACL_WHERE_EXPN, rc, user_msg, log_msg);
5268 BOOL save_log_testing_mode = log_testing_mode;
5269 address_test_mode = log_testing_mode = TRUE;
5270 (void) verify_address(deliver_make_addr(smtp_cmd_data, FALSE),
5271 smtp_out, vopt_is_recipient | vopt_qualify | vopt_expn, -1, -1, -1,
5273 address_test_mode = FALSE;
5274 log_testing_mode = save_log_testing_mode; /* true for -bh */
5283 if (!tls_advertised)
5285 done = synprot_error(L_smtp_protocol_error, 503, NULL,
5286 US"STARTTLS command used when not advertised");
5290 /* Apply an ACL check if one is defined */
5292 if ( acl_smtp_starttls
5293 && (rc = acl_check(ACL_WHERE_STARTTLS, NULL, acl_smtp_starttls,
5294 &user_msg, &log_msg)) != OK
5297 done = smtp_handle_acl_fail(ACL_WHERE_STARTTLS, rc, user_msg, log_msg);
5301 /* RFC 2487 is not clear on when this command may be sent, though it
5302 does state that all information previously obtained from the client
5303 must be discarded if a TLS session is started. It seems reasonable to
5304 do an implied RSET when STARTTLS is received. */
5306 incomplete_transaction_log(US"STARTTLS");
5307 cancel_cutthrough_connection(TRUE, US"STARTTLS received");
5308 smtp_reset(reset_point);
5310 cmd_list[CMD_LIST_STARTTLS].is_mail_cmd = FALSE;
5312 /* There's an attack where more data is read in past the STARTTLS command
5313 before TLS is negotiated, then assumed to be part of the secure session
5314 when used afterwards; we use segregated input buffers, so are not
5315 vulnerable, but we want to note when it happens and, for sheer paranoia,
5316 ensure that the buffer is "wiped".
5317 Pipelining sync checks will normally have protected us too, unless disabled
5318 by configuration. */
5320 if (receive_smtp_buffered())
5323 debug_printf("Non-empty input buffer after STARTTLS; naive attack?\n");
5324 if (tls_in.active < 0)
5325 smtp_inend = smtp_inptr = smtp_inbuffer;
5326 /* and if TLS is already active, tls_server_start() should fail */
5329 /* There is nothing we value in the input buffer and if TLS is successfully
5330 negotiated, we won't use this buffer again; if TLS fails, we'll just read
5331 fresh content into it. The buffer contains arbitrary content from an
5332 untrusted remote source; eg: NOOP <shellcode>\r\nSTARTTLS\r\n
5333 It seems safest to just wipe away the content rather than leave it as a
5334 target to jump to. */
5336 memset(smtp_inbuffer, 0, IN_BUFFER_SIZE);
5338 /* Attempt to start up a TLS session, and if successful, discard all
5339 knowledge that was obtained previously. At least, that's what the RFC says,
5340 and that's what happens by default. However, in order to work round YAEB,
5341 there is an option to remember the esmtp state. Sigh.
5343 We must allow for an extra EHLO command and an extra AUTH command after
5344 STARTTLS that don't add to the nonmail command count. */
5347 if ((rc = tls_server_start(tls_require_ciphers, &s)) == OK)
5349 if (!tls_remember_esmtp)
5350 helo_seen = esmtp = auth_advertised = pipelining_advertised = FALSE;
5351 cmd_list[CMD_LIST_EHLO].is_mail_cmd = TRUE;
5352 cmd_list[CMD_LIST_AUTH].is_mail_cmd = TRUE;
5353 cmd_list[CMD_LIST_TLS_AUTH].is_mail_cmd = TRUE;
5354 if (sender_helo_name)
5356 store_free(sender_helo_name);
5357 sender_helo_name = NULL;
5358 host_build_sender_fullhost(); /* Rebuild */
5359 set_process_info("handling incoming TLS connection from %s",
5360 host_and_ident(FALSE));
5363 (sender_host_address ? protocols : protocols_local)
5365 ? pextend + (sender_host_authenticated ? pauthed : 0)
5367 + (tls_in.active >= 0 ? pcrpted : 0)
5370 sender_host_auth_pubname = sender_host_authenticated = NULL;
5371 authenticated_id = NULL;
5372 sync_cmd_limit = NON_SYNC_CMD_NON_PIPELINING;
5373 DEBUG(D_tls) debug_printf("TLS active\n");
5374 break; /* Successful STARTTLS */
5377 (void) smtp_log_tls_fail(s);
5379 /* Some local configuration problem was discovered before actually trying
5380 to do a TLS handshake; give a temporary error. */
5384 smtp_printf("454 TLS currently unavailable\r\n", FALSE);
5388 /* Hard failure. Reject everything except QUIT or closed connection. One
5389 cause for failure is a nested STARTTLS, in which case tls_in.active remains
5390 set, but we must still reject all incoming commands. */
5392 DEBUG(D_tls) debug_printf("TLS failed to start\n");
5393 while (done <= 0) switch(smtp_read_command(FALSE, GETC_BUFFER_UNLIMITED))
5396 log_write(L_smtp_connection, LOG_MAIN, "%s closed by EOF",
5397 smtp_get_connection_info());
5398 smtp_notquit_exit(US"tls-failed", NULL, NULL);
5402 /* It is perhaps arguable as to which exit ACL should be called here,
5403 but as it is probably a situation that almost never arises, it
5404 probably doesn't matter. We choose to call the real QUIT ACL, which in
5405 some sense is perhaps "right". */
5410 && ((rc = acl_check(ACL_WHERE_QUIT, NULL, acl_smtp_quit, &user_msg,
5411 &log_msg)) == ERROR))
5412 log_write(0, LOG_MAIN|LOG_PANIC, "ACL for QUIT returned ERROR: %s",
5415 smtp_respond(US"221", 3, TRUE, user_msg);
5417 smtp_printf("221 %s closing connection\r\n", FALSE, smtp_active_hostname);
5418 log_write(L_smtp_connection, LOG_MAIN, "%s closed by QUIT",
5419 smtp_get_connection_info());
5424 smtp_printf("554 Security failure\r\n", FALSE);
5427 tls_close(TRUE, TLS_SHUTDOWN_NOWAIT);
5432 /* The ACL for QUIT is provided for gathering statistical information or
5433 similar; it does not affect the response code, but it can supply a custom
5437 smtp_quit_handler(&user_msg, &log_msg);
5443 smtp_rset_handler();
5444 cancel_cutthrough_connection(TRUE, US"RSET received");
5445 smtp_reset(reset_point);
5452 smtp_printf("250 OK\r\n", FALSE);
5456 /* Show ETRN/EXPN/VRFY if there's an ACL for checking hosts; if actually
5457 used, a check will be done for permitted hosts. Show STARTTLS only if not
5458 already in a TLS session and if it would be advertised in the EHLO
5463 smtp_printf("214-Commands supported:\r\n", TRUE);
5467 Ustrcat(buffer, " AUTH");
5469 if (tls_in.active < 0 &&
5470 verify_check_host(&tls_advertise_hosts) != FAIL)
5471 Ustrcat(buffer, " STARTTLS");
5473 Ustrcat(buffer, " HELO EHLO MAIL RCPT DATA BDAT");
5474 Ustrcat(buffer, " NOOP QUIT RSET HELP");
5475 if (acl_smtp_etrn != NULL) Ustrcat(buffer, " ETRN");
5476 if (acl_smtp_expn != NULL) Ustrcat(buffer, " EXPN");
5477 if (acl_smtp_vrfy != NULL) Ustrcat(buffer, " VRFY");
5478 smtp_printf("214%s\r\n", FALSE, buffer);
5484 incomplete_transaction_log(US"connection lost");
5485 smtp_notquit_exit(US"connection-lost", US"421",
5486 US"%s lost input connection", smtp_active_hostname);
5488 /* Don't log by default unless in the middle of a message, as some mailers
5489 just drop the call rather than sending QUIT, and it clutters up the logs.
5492 if (sender_address || recipients_count > 0)
5493 log_write(L_lost_incoming_connection, LOG_MAIN,
5494 "unexpected %s while reading SMTP command from %s%s%s D=%s",
5495 sender_host_unknown ? "EOF" : "disconnection",
5496 tcp_in_fastopen && !tcp_in_fastopen_logged ? US"TFO " : US"",
5497 host_and_ident(FALSE), smtp_read_error,
5498 string_timesince(&smtp_connection_start)
5502 log_write(L_smtp_connection, LOG_MAIN, "%s %slost%s D=%s",
5503 smtp_get_connection_info(),
5504 tcp_in_fastopen && !tcp_in_fastopen_logged ? US"TFO " : US"",
5506 string_timesince(&smtp_connection_start)
5517 done = synprot_error(L_smtp_protocol_error, 503, NULL,
5518 US"ETRN is not permitted inside a transaction");
5522 log_write(L_etrn, LOG_MAIN, "ETRN %s received from %s", smtp_cmd_argument,
5523 host_and_ident(FALSE));
5525 if ((rc = acl_check(ACL_WHERE_ETRN, NULL, acl_smtp_etrn,
5526 &user_msg, &log_msg)) != OK)
5528 done = smtp_handle_acl_fail(ACL_WHERE_ETRN, rc, user_msg, log_msg);
5532 /* Compute the serialization key for this command. */
5534 etrn_serialize_key = string_sprintf("etrn-%s\n", smtp_cmd_data);
5536 /* If a command has been specified for running as a result of ETRN, we
5537 permit any argument to ETRN. If not, only the # standard form is permitted,
5538 since that is strictly the only kind of ETRN that can be implemented
5539 according to the RFC. */
5541 if (smtp_etrn_command)
5545 etrn_command = smtp_etrn_command;
5546 deliver_domain = smtp_cmd_data;
5547 rc = transport_set_up_command(&argv, smtp_etrn_command, TRUE, 0, NULL,
5548 US"ETRN processing", &error);
5549 deliver_domain = NULL;
5552 log_write(0, LOG_MAIN|LOG_PANIC, "failed to set up ETRN command: %s",
5554 smtp_printf("458 Internal failure\r\n", FALSE);
5559 /* Else set up to call Exim with the -R option. */
5563 if (*smtp_cmd_data++ != '#')
5565 done = synprot_error(L_smtp_syntax_error, 501, NULL,
5566 US"argument must begin with #");
5569 etrn_command = US"exim -R";
5570 argv = CUSS child_exec_exim(CEE_RETURN_ARGV, TRUE, NULL, TRUE,
5571 *queue_name ? 4 : 2,
5572 US"-R", smtp_cmd_data,
5573 US"-MCG", queue_name);
5576 /* If we are host-testing, don't actually do anything. */
5582 debug_printf("ETRN command is: %s\n", etrn_command);
5583 debug_printf("ETRN command execution skipped\n");
5585 if (user_msg == NULL) smtp_printf("250 OK\r\n", FALSE);
5586 else smtp_user_msg(US"250", user_msg);
5591 /* If ETRN queue runs are to be serialized, check the database to
5592 ensure one isn't already running. */
5594 if (smtp_etrn_serialize && !enq_start(etrn_serialize_key, 1))
5596 smtp_printf("458 Already processing %s\r\n", FALSE, smtp_cmd_data);
5600 /* Fork a child process and run the command. We don't want to have to
5601 wait for the process at any point, so set SIGCHLD to SIG_IGN before
5602 forking. It should be set that way anyway for external incoming SMTP,
5603 but we save and restore to be tidy. If serialization is required, we
5604 actually run the command in yet another process, so we can wait for it
5605 to complete and then remove the serialization lock. */
5607 oldsignal = signal(SIGCHLD, SIG_IGN);
5609 if ((pid = fork()) == 0)
5611 smtp_input = FALSE; /* This process is not associated with the */
5612 (void)fclose(smtp_in); /* SMTP call any more. */
5613 (void)fclose(smtp_out);
5615 signal(SIGCHLD, SIG_DFL); /* Want to catch child */
5617 /* If not serializing, do the exec right away. Otherwise, fork down
5618 into another process. */
5620 if (!smtp_etrn_serialize || (pid = fork()) == 0)
5622 DEBUG(D_exec) debug_print_argv(argv);
5623 exim_nullstd(); /* Ensure std{in,out,err} exist */
5624 execv(CS argv[0], (char *const *)argv);
5625 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "exec of \"%s\" (ETRN) failed: %s",
5626 etrn_command, strerror(errno));
5627 _exit(EXIT_FAILURE); /* paranoia */
5630 /* Obey this if smtp_serialize and the 2nd fork yielded non-zero. That
5631 is, we are in the first subprocess, after forking again. All we can do
5632 for a failing fork is to log it. Otherwise, wait for the 2nd process to
5633 complete, before removing the serialization. */
5636 log_write(0, LOG_MAIN|LOG_PANIC, "2nd fork for serialized ETRN "
5637 "failed: %s", strerror(errno));
5641 DEBUG(D_any) debug_printf("waiting for serialized ETRN process %d\n",
5643 (void)wait(&status);
5644 DEBUG(D_any) debug_printf("serialized ETRN process %d ended\n",
5648 enq_end(etrn_serialize_key);
5649 _exit(EXIT_SUCCESS);
5652 /* Back in the top level SMTP process. Check that we started a subprocess
5653 and restore the signal state. */
5657 log_write(0, LOG_MAIN|LOG_PANIC, "fork of process for ETRN failed: %s",
5659 smtp_printf("458 Unable to fork process\r\n", FALSE);
5660 if (smtp_etrn_serialize) enq_end(etrn_serialize_key);
5664 if (user_msg == NULL) smtp_printf("250 OK\r\n", FALSE);
5665 else smtp_user_msg(US"250", user_msg);
5668 signal(SIGCHLD, oldsignal);
5673 done = synprot_error(L_smtp_syntax_error, 501, NULL,
5674 US"unexpected argument data");
5678 /* This currently happens only for NULLs, but could be extended. */
5681 done = synprot_error(L_smtp_syntax_error, 0, NULL, /* Just logs */
5682 US"NUL character(s) present (shown as '?')");
5683 smtp_printf("501 NUL characters are not allowed in SMTP commands\r\n", FALSE);
5689 if (smtp_inend >= smtp_inbuffer + IN_BUFFER_SIZE)
5690 smtp_inend = smtp_inbuffer + IN_BUFFER_SIZE - 1;
5691 c = smtp_inend - smtp_inptr;
5692 if (c > 150) c = 150; /* limit logged amount */
5694 incomplete_transaction_log(US"sync failure");
5695 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP protocol synchronization error "
5696 "(next input sent too soon: pipelining was%s advertised): "
5697 "rejected \"%s\" %s next input=\"%s\"",
5698 pipelining_advertised? "" : " not",
5699 smtp_cmd_buffer, host_and_ident(TRUE),
5700 string_printing(smtp_inptr));
5701 smtp_notquit_exit(US"synchronization-error", US"554",
5702 US"SMTP synchronization error");
5703 done = 1; /* Pretend eof - drops connection */
5707 case TOO_MANY_NONMAIL_CMD:
5708 s = smtp_cmd_buffer;
5709 while (*s != 0 && !isspace(*s)) s++;
5710 incomplete_transaction_log(US"too many non-mail commands");
5711 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
5712 "nonmail commands (last was \"%.*s\")", host_and_ident(FALSE),
5713 (int)(s - smtp_cmd_buffer), smtp_cmd_buffer);
5714 smtp_notquit_exit(US"bad-commands", US"554", US"Too many nonmail commands");
5715 done = 1; /* Pretend eof - drops connection */
5718 #ifdef SUPPORT_PROXY
5719 case PROXY_FAIL_IGNORE_CMD:
5720 smtp_printf("503 Command refused, required Proxy negotiation failed\r\n", FALSE);
5725 if (unknown_command_count++ >= smtp_max_unknown_commands)
5727 log_write(L_smtp_syntax_error, LOG_MAIN,
5728 "SMTP syntax error in \"%s\" %s %s",
5729 string_printing(smtp_cmd_buffer), host_and_ident(TRUE),
5730 US"unrecognized command");
5731 incomplete_transaction_log(US"unrecognized command");
5732 smtp_notquit_exit(US"bad-commands", US"500",
5733 US"Too many unrecognized commands");
5735 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
5736 "unrecognized commands (last was \"%s\")", host_and_ident(FALSE),
5737 string_printing(smtp_cmd_buffer));
5740 done = synprot_error(L_smtp_syntax_error, 500, NULL,
5741 US"unrecognized command");
5745 /* This label is used by goto's inside loops that want to break out to
5746 the end of the command-processing loop. */
5749 last_was_rej_mail = was_rej_mail; /* Remember some last commands for */
5750 last_was_rcpt = was_rcpt; /* protocol error handling */
5754 return done - 2; /* Convert yield values */
5760 authres_smtpauth(gstring * g)
5762 if (!sender_host_authenticated)
5765 g = string_append(g, 2, US";\n\tauth=pass (", sender_host_auth_pubname);
5767 if (Ustrcmp(sender_host_auth_pubname, "tls") != 0)
5768 g = string_append(g, 2, US") smtp.auth=", authenticated_id);
5769 else if (authenticated_id)
5770 g = string_append(g, 2, US") x509.auth=", authenticated_id);
5772 g = string_catn(g, US") reason=x509.auth", 17);
5774 if (authenticated_sender)
5775 g = string_append(g, 2, US" smtp.mailfrom=", authenticated_sender);
5783 /* End of smtp_in.c */