1 /*************************************************
2 * Exim - an Internet mail transport agent *
3 *************************************************/
5 /* Copyright (c) University of Cambridge 1995 - 2018 */
6 /* See the file NOTICE for conditions of use and distribution. */
8 /* Functions for handling an incoming SMTP call. */
15 /* Initialize for TCP wrappers if so configured. It appears that the macro
16 HAVE_IPV6 is used in some versions of the tcpd.h header, so we unset it before
17 including that header, and restore its value afterwards. */
19 #ifdef USE_TCP_WRAPPERS
22 #define EXIM_HAVE_IPV6
28 #define HAVE_IPV6 TRUE
31 int allow_severity = LOG_INFO;
32 int deny_severity = LOG_NOTICE;
33 uschar *tcp_wrappers_name;
37 /* Size of buffer for reading SMTP commands. We used to use 512, as defined
38 by RFC 821. However, RFC 1869 specifies that this must be increased for SMTP
39 commands that accept arguments, and this in particular applies to AUTH, where
40 the data can be quite long. More recently this value was 2048 in Exim;
41 however, RFC 4954 (circa 2007) recommends 12288 bytes to handle AUTH. Clients
42 such as Thunderbird will send an AUTH with an initial-response for GSSAPI.
43 The maximum size of a Kerberos ticket under Windows 2003 is 12000 bytes, and
44 we need room to handle large base64-encoded AUTHs for GSSAPI.
47 #define SMTP_CMD_BUFFER_SIZE 16384
49 /* Size of buffer for reading SMTP incoming packets */
51 #define IN_BUFFER_SIZE 8192
53 /* Structure for SMTP command list */
60 short int is_mail_cmd;
63 /* Codes for identifying commands. We order them so that those that come first
64 are those for which synchronization is always required. Checking this can help
68 /* These commands are required to be synchronized, i.e. to be the last in a
69 block of commands when pipelining. */
71 HELO_CMD, EHLO_CMD, DATA_CMD, /* These are listed in the pipelining */
72 VRFY_CMD, EXPN_CMD, NOOP_CMD, /* RFC as requiring synchronization */
73 ETRN_CMD, /* This by analogy with TURN from the RFC */
74 STARTTLS_CMD, /* Required by the STARTTLS RFC */
75 TLS_AUTH_CMD, /* auto-command at start of SSL */
77 /* This is a dummy to identify the non-sync commands when pipelining */
79 NON_SYNC_CMD_PIPELINING,
81 /* These commands need not be synchronized when pipelining */
83 MAIL_CMD, RCPT_CMD, RSET_CMD,
85 /* This is a dummy to identify the non-sync commands when not pipelining */
87 NON_SYNC_CMD_NON_PIPELINING,
89 /* RFC3030 section 2: "After all MAIL and RCPT responses are collected and
90 processed the message is sent using a series of BDAT commands"
91 implies that BDAT should be synchronized. However, we see Google, at least,
92 sending MAIL,RCPT,BDAT-LAST in a single packet, clearly not waiting for
93 processing of the RCPT response(s). We shall do the same, and not require
94 synch for BDAT. Worse, as the chunk may (very likely will) follow the
95 command-header in the same packet we cannot do the usual "is there any
96 follow-on data after the command line" even for non-pipeline mode.
97 So we'll need an explicit check after reading the expected chunk amount
98 when non-pipe, before sending the ACK. */
102 /* I have been unable to find a statement about the use of pipelining
103 with AUTH, so to be on the safe side it is here, though I kind of feel
104 it should be up there with the synchronized commands. */
108 /* I'm not sure about these, but I don't think they matter. */
113 PROXY_FAIL_IGNORE_CMD,
116 /* These are specials that don't correspond to actual commands */
118 EOF_CMD, OTHER_CMD, BADARG_CMD, BADCHAR_CMD, BADSYN_CMD,
119 TOO_MANY_NONMAIL_CMD };
122 /* This is a convenience macro for adding the identity of an SMTP command
123 to the circular buffer that holds a list of the last n received. */
126 smtp_connection_had[smtp_ch_index++] = n; \
127 if (smtp_ch_index >= SMTP_HBUFF_SIZE) smtp_ch_index = 0
130 /*************************************************
131 * Local static variables *
132 *************************************************/
134 static auth_instance *authenticated_by;
135 static BOOL auth_advertised;
137 static BOOL tls_advertised;
139 static BOOL dsn_advertised;
141 static BOOL helo_required = FALSE;
142 static BOOL helo_verify = FALSE;
143 static BOOL helo_seen;
144 static BOOL helo_accept_junk;
145 static BOOL count_nonmail;
146 static BOOL pipelining_advertised;
147 static BOOL rcpt_smtp_response_same;
148 static BOOL rcpt_in_progress;
149 static int nonmail_command_count;
150 static BOOL smtp_exit_function_called = 0;
152 static BOOL smtputf8_advertised;
154 static int synprot_error_count;
155 static int unknown_command_count;
156 static int sync_cmd_limit;
157 static int smtp_write_error = 0;
159 static uschar *rcpt_smtp_response;
160 static uschar *smtp_data_buffer;
161 static uschar *smtp_cmd_data;
163 /* We need to know the position of RSET, HELO, EHLO, AUTH, and STARTTLS. Their
164 final fields of all except AUTH are forced TRUE at the start of a new message
165 setup, to allow one of each between messages that is not counted as a nonmail
166 command. (In fact, only one of HELO/EHLO is not counted.) Also, we have to
167 allow a new EHLO after starting up TLS.
169 AUTH is "falsely" labelled as a mail command initially, so that it doesn't get
170 counted. However, the flag is changed when AUTH is received, so that multiple
171 failing AUTHs will eventually hit the limit. After a successful AUTH, another
172 AUTH is already forbidden. After a TLS session is started, AUTH's flag is again
173 forced TRUE, to allow for the re-authentication that can happen at that point.
175 QUIT is also "falsely" labelled as a mail command so that it doesn't up the
176 count of non-mail commands and possibly provoke an error.
178 tls_auth is a pseudo-command, never expected in input. It is activated
179 on TLS startup and looks for a tls authenticator. */
181 static smtp_cmd_list cmd_list[] = {
182 /* name len cmd has_arg is_mail_cmd */
184 { "rset", sizeof("rset")-1, RSET_CMD, FALSE, FALSE }, /* First */
185 { "helo", sizeof("helo")-1, HELO_CMD, TRUE, FALSE },
186 { "ehlo", sizeof("ehlo")-1, EHLO_CMD, TRUE, FALSE },
187 { "auth", sizeof("auth")-1, AUTH_CMD, TRUE, TRUE },
189 { "starttls", sizeof("starttls")-1, STARTTLS_CMD, FALSE, FALSE },
190 { "tls_auth", 0, TLS_AUTH_CMD, FALSE, FALSE },
193 /* If you change anything above here, also fix the definitions below. */
195 { "mail from:", sizeof("mail from:")-1, MAIL_CMD, TRUE, TRUE },
196 { "rcpt to:", sizeof("rcpt to:")-1, RCPT_CMD, TRUE, TRUE },
197 { "data", sizeof("data")-1, DATA_CMD, FALSE, TRUE },
198 { "bdat", sizeof("bdat")-1, BDAT_CMD, TRUE, TRUE },
199 { "quit", sizeof("quit")-1, QUIT_CMD, FALSE, TRUE },
200 { "noop", sizeof("noop")-1, NOOP_CMD, TRUE, FALSE },
201 { "etrn", sizeof("etrn")-1, ETRN_CMD, TRUE, FALSE },
202 { "vrfy", sizeof("vrfy")-1, VRFY_CMD, TRUE, FALSE },
203 { "expn", sizeof("expn")-1, EXPN_CMD, TRUE, FALSE },
204 { "help", sizeof("help")-1, HELP_CMD, TRUE, FALSE }
207 static smtp_cmd_list *cmd_list_end =
208 cmd_list + sizeof(cmd_list)/sizeof(smtp_cmd_list);
210 #define CMD_LIST_RSET 0
211 #define CMD_LIST_HELO 1
212 #define CMD_LIST_EHLO 2
213 #define CMD_LIST_AUTH 3
214 #define CMD_LIST_STARTTLS 4
215 #define CMD_LIST_TLS_AUTH 5
217 /* This list of names is used for performing the smtp_no_mail logging action.
218 It must be kept in step with the SCH_xxx enumerations. */
220 static uschar *smtp_names[] =
222 US"NONE", US"AUTH", US"DATA", US"BDAT", US"EHLO", US"ETRN", US"EXPN",
223 US"HELO", US"HELP", US"MAIL", US"NOOP", US"QUIT", US"RCPT", US"RSET",
224 US"STARTTLS", US"VRFY" };
226 static uschar *protocols_local[] = {
227 US"local-smtp", /* HELO */
228 US"local-smtps", /* The rare case EHLO->STARTTLS->HELO */
229 US"local-esmtp", /* EHLO */
230 US"local-esmtps", /* EHLO->STARTTLS->EHLO */
231 US"local-esmtpa", /* EHLO->AUTH */
232 US"local-esmtpsa" /* EHLO->STARTTLS->EHLO->AUTH */
234 static uschar *protocols[] = {
236 US"smtps", /* The rare case EHLO->STARTTLS->HELO */
237 US"esmtp", /* EHLO */
238 US"esmtps", /* EHLO->STARTTLS->EHLO */
239 US"esmtpa", /* EHLO->AUTH */
240 US"esmtpsa" /* EHLO->STARTTLS->EHLO->AUTH */
245 #define pcrpted 1 /* added to pextend or pnormal */
246 #define pauthed 2 /* added to pextend */
248 /* Sanity check and validate optional args to MAIL FROM: envelope */
251 ENV_MAIL_OPT_SIZE, ENV_MAIL_OPT_BODY, ENV_MAIL_OPT_AUTH,
255 ENV_MAIL_OPT_RET, ENV_MAIL_OPT_ENVID,
261 uschar * name; /* option requested during MAIL cmd */
262 int value; /* enum type */
263 BOOL need_value; /* TRUE requires value (name=value pair format)
264 FALSE is a singleton */
266 static env_mail_type_t env_mail_type_list[] = {
267 { US"SIZE", ENV_MAIL_OPT_SIZE, TRUE },
268 { US"BODY", ENV_MAIL_OPT_BODY, TRUE },
269 { US"AUTH", ENV_MAIL_OPT_AUTH, TRUE },
271 { US"PRDR", ENV_MAIL_OPT_PRDR, FALSE },
273 { US"RET", ENV_MAIL_OPT_RET, TRUE },
274 { US"ENVID", ENV_MAIL_OPT_ENVID, TRUE },
276 { US"SMTPUTF8",ENV_MAIL_OPT_UTF8, FALSE }, /* rfc6531 */
278 /* keep this the last entry */
279 { US"NULL", ENV_MAIL_OPT_NULL, FALSE },
282 /* When reading SMTP from a remote host, we have to use our own versions of the
283 C input-reading functions, in order to be able to flush the SMTP output only
284 when about to read more data from the socket. This is the only way to get
285 optimal performance when the client is using pipelining. Flushing for every
286 command causes a separate packet and reply packet each time; saving all the
287 responses up (when pipelining) combines them into one packet and one response.
289 For simplicity, these functions are used for *all* SMTP input, not only when
290 receiving over a socket. However, after setting up a secure socket (SSL), input
291 is read via the OpenSSL library, and another set of functions is used instead
294 These functions are set in the receive_getc etc. variables and called with the
295 same interface as the C functions. However, since there can only ever be
296 one incoming SMTP call, we just use a single buffer and flags. There is no need
297 to implement a complicated private FILE-like structure.*/
299 static uschar *smtp_inbuffer;
300 static uschar *smtp_inptr;
301 static uschar *smtp_inend;
302 static int smtp_had_eof;
303 static int smtp_had_error;
306 /* forward declarations */
307 static int smtp_read_command(BOOL check_sync, unsigned buffer_lim);
308 static int synprot_error(int type, int code, uschar *data, uschar *errmess);
309 static void smtp_quit_handler(uschar **, uschar **);
310 static void smtp_rset_handler(void);
312 /*************************************************
313 * Recheck synchronization *
314 *************************************************/
316 /* Synchronization checks can never be perfect because a packet may be on its
317 way but not arrived when the check is done. Normally, the checks happen when
318 commands are read: Exim ensures that there is no more input in the input buffer.
319 In normal cases, the response to the command will be fast, and there is no
322 However, for some commands an ACL is run, and that can include delays. In those
323 cases, it is useful to do another check on the input just before sending the
324 response. This also applies at the start of a connection. This function does
325 that check by means of the select() function, as long as the facility is not
326 disabled or inappropriate. A failure of select() is ignored.
328 When there is unwanted input, we read it so that it appears in the log of the
332 Returns: TRUE if all is well; FALSE if there is input pending
336 wouldblock_reading(void)
340 struct timeval tzero;
343 if (tls_in.active >= 0)
344 return !tls_could_read();
347 if (smtp_inptr < smtp_inend)
350 fd = fileno(smtp_in);
355 rc = select(fd + 1, (SELECT_ARG2_TYPE *)&fds, NULL, NULL, &tzero);
357 if (rc <= 0) return TRUE; /* Not ready to read */
358 rc = smtp_getc(GETC_BUFFER_UNLIMITED);
359 if (rc < 0) return TRUE; /* End of file or error */
368 if (!smtp_enforce_sync || !sender_host_address || sender_host_notsocket)
371 return wouldblock_reading();
375 /* If there's input waiting (and we're doing pipelineing) then we can pipeline
376 a reponse with the one following. */
379 pipeline_response(void)
381 if ( !smtp_enforce_sync || !sender_host_address
382 || sender_host_notsocket || !pipelining_advertised)
385 return !wouldblock_reading();
390 /*************************************************
391 * Log incomplete transactions *
392 *************************************************/
394 /* This function is called after a transaction has been aborted by RSET, QUIT,
395 connection drops or other errors. It logs the envelope information received
396 so far in order to preserve address verification attempts.
398 Argument: string to indicate what aborted the transaction
403 incomplete_transaction_log(uschar *what)
405 if (sender_address == NULL || /* No transaction in progress */
406 !LOGGING(smtp_incomplete_transaction))
409 /* Build list of recipients for logging */
411 if (recipients_count > 0)
414 raw_recipients = store_get(recipients_count * sizeof(uschar *));
415 for (i = 0; i < recipients_count; i++)
416 raw_recipients[i] = recipients_list[i].address;
417 raw_recipients_count = recipients_count;
420 log_write(L_smtp_incomplete_transaction, LOG_MAIN|LOG_SENDER|LOG_RECIPIENTS,
421 "%s incomplete transaction (%s)", host_and_ident(TRUE), what);
427 /* Refill the buffer, and notify DKIM verification code.
428 Return false for error or EOF.
432 smtp_refill(unsigned lim)
435 if (!smtp_out) return FALSE;
437 if (smtp_receive_timeout > 0) alarm(smtp_receive_timeout);
439 /* Limit amount read, so non-message data is not fed to DKIM.
440 Take care to not touch the safety NUL at the end of the buffer. */
442 rc = read(fileno(smtp_in), smtp_inbuffer, MIN(IN_BUFFER_SIZE-1, lim));
447 /* Must put the error text in fixed store, because this might be during
448 header reading, where it releases unused store above the header. */
451 smtp_had_error = save_errno;
452 smtp_read_error = string_copy_malloc(
453 string_sprintf(" (error: %s)", strerror(save_errno)));
455 else smtp_had_eof = 1;
459 dkim_exim_verify_feed(smtp_inbuffer, rc);
461 smtp_inend = smtp_inbuffer + rc;
462 smtp_inptr = smtp_inbuffer;
466 /*************************************************
467 * SMTP version of getc() *
468 *************************************************/
470 /* This gets the next byte from the SMTP input buffer. If the buffer is empty,
471 it flushes the output, and refills the buffer, with a timeout. The signal
472 handler is set appropriately by the calling function. This function is not used
473 after a connection has negotiated itself into an TLS/SSL state.
475 Arguments: lim Maximum amount to read/buffer
476 Returns: the next character or EOF
480 smtp_getc(unsigned lim)
482 if (smtp_inptr >= smtp_inend)
483 if (!smtp_refill(lim))
485 return *smtp_inptr++;
489 smtp_getbuf(unsigned * len)
494 if (smtp_inptr >= smtp_inend)
495 if (!smtp_refill(*len))
496 { *len = 0; return NULL; }
498 if ((size = smtp_inend - smtp_inptr) > *len) size = *len;
509 int n = smtp_inend - smtp_inptr;
511 dkim_exim_verify_feed(smtp_inptr, n);
516 /* Get a byte from the smtp input, in CHUNKING mode. Handle ack of the
517 previous BDAT chunk and getting new ones when we run out. Uses the
518 underlying smtp_getc or tls_getc both for that and for getting the
519 (buffered) data byte. EOD signals (an expected) no further data.
520 ERR signals a protocol error, and EOF a closed input stream.
522 Called from read_bdat_smtp() in receive.c for the message body, but also
523 by the headers read loop in receive_msg(); manipulates chunking_state
524 to handle the BDAT command/response.
525 Placed here due to the correlation with the above smtp_getc(), which it wraps,
526 and also by the need to do smtp command/response handling.
528 Arguments: lim (ignored)
529 Returns: the next character or ERR, EOD or EOF
533 bdat_getc(unsigned lim)
535 uschar * user_msg = NULL;
544 if (chunking_data_left > 0)
545 return lwr_receive_getc(chunking_data_left--);
547 receive_getc = lwr_receive_getc;
548 receive_getbuf = lwr_receive_getbuf;
549 receive_ungetc = lwr_receive_ungetc;
551 dkim_save = dkim_collect_input;
552 dkim_collect_input = FALSE;
555 /* Unless PIPELINING was offered, there should be no next command
556 until after we ack that chunk */
558 if (!pipelining_advertised && !check_sync())
560 unsigned n = smtp_inend - smtp_inptr;
563 incomplete_transaction_log(US"sync failure");
564 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP protocol synchronization error "
565 "(next input sent too soon: pipelining was not advertised): "
566 "rejected \"%s\" %s next input=\"%s\"%s",
567 smtp_cmd_buffer, host_and_ident(TRUE),
568 string_printing(string_copyn(smtp_inptr, n)),
569 smtp_inend - smtp_inptr > n ? "..." : "");
570 (void) synprot_error(L_smtp_protocol_error, 554, NULL,
571 US"SMTP synchronization error");
572 goto repeat_until_rset;
575 /* If not the last, ack the received chunk. The last response is delayed
576 until after the data ACL decides on it */
578 if (chunking_state == CHUNKING_LAST)
581 dkim_exim_verify_feed(NULL, 0); /* notify EOD */
586 smtp_printf("250 %u byte chunk received\r\n", FALSE, chunking_datasize);
587 chunking_state = CHUNKING_OFFERED;
588 DEBUG(D_receive) debug_printf("chunking state %d\n", (int)chunking_state);
590 /* Expect another BDAT cmd from input. RFC 3030 says nothing about
591 QUIT, RSET or NOOP but handling them seems obvious */
594 switch(smtp_read_command(TRUE, 1))
597 (void) synprot_error(L_smtp_protocol_error, 503, NULL,
598 US"only BDAT permissible after non-LAST BDAT");
601 switch(smtp_read_command(TRUE, 1))
603 case QUIT_CMD: smtp_quit_handler(&user_msg, &log_msg); /*FALLTHROUGH */
604 case EOF_CMD: return EOF;
605 case RSET_CMD: smtp_rset_handler(); return ERR;
606 default: if (synprot_error(L_smtp_protocol_error, 503, NULL,
607 US"only RSET accepted now") > 0)
609 goto repeat_until_rset;
613 smtp_quit_handler(&user_msg, &log_msg);
624 smtp_printf("250 OK\r\n", FALSE);
631 if (sscanf(CS smtp_cmd_data, "%u %n", &chunking_datasize, &n) < 1)
633 (void) synprot_error(L_smtp_protocol_error, 501, NULL,
634 US"missing size for BDAT command");
637 chunking_state = strcmpic(smtp_cmd_data+n, US"LAST") == 0
638 ? CHUNKING_LAST : CHUNKING_ACTIVE;
639 chunking_data_left = chunking_datasize;
640 DEBUG(D_receive) debug_printf("chunking state %d, %d bytes\n",
641 (int)chunking_state, chunking_data_left);
643 if (chunking_datasize == 0)
644 if (chunking_state == CHUNKING_LAST)
648 (void) synprot_error(L_smtp_protocol_error, 504, NULL,
649 US"zero size for BDAT command");
650 goto repeat_until_rset;
653 receive_getc = bdat_getc;
654 receive_getbuf = bdat_getbuf; /* r~getbuf is never actually used */
655 receive_ungetc = bdat_ungetc;
657 dkim_collect_input = dkim_save;
659 break; /* to top of main loop */
666 bdat_getbuf(unsigned * len)
670 if (chunking_data_left <= 0)
671 { *len = 0; return NULL; }
673 if (*len > chunking_data_left) *len = chunking_data_left;
674 buf = lwr_receive_getbuf(len); /* Either smtp_getbuf or tls_getbuf */
675 chunking_data_left -= *len;
680 bdat_flush_data(void)
682 while (chunking_data_left)
684 unsigned n = chunking_data_left;
685 if (!bdat_getbuf(&n)) break;
688 receive_getc = lwr_receive_getc;
689 receive_getbuf = lwr_receive_getbuf;
690 receive_ungetc = lwr_receive_ungetc;
692 if (chunking_state != CHUNKING_LAST)
694 chunking_state = CHUNKING_OFFERED;
695 DEBUG(D_receive) debug_printf("chunking state %d\n", (int)chunking_state);
702 /*************************************************
703 * SMTP version of ungetc() *
704 *************************************************/
706 /* Puts a character back in the input buffer. Only ever
712 Returns: the character
726 chunking_data_left++;
727 return lwr_receive_ungetc(ch);
732 /*************************************************
733 * SMTP version of feof() *
734 *************************************************/
736 /* Tests for a previous EOF
739 Returns: non-zero if the eof flag is set
751 /*************************************************
752 * SMTP version of ferror() *
753 *************************************************/
755 /* Tests for a previous read error, and returns with errno
756 restored to what it was when the error was detected.
759 Returns: non-zero if the error flag is set
765 errno = smtp_had_error;
766 return smtp_had_error;
771 /*************************************************
772 * Test for characters in the SMTP buffer *
773 *************************************************/
775 /* Used at the end of a message
784 return smtp_inptr < smtp_inend;
789 /*************************************************
790 * Write formatted string to SMTP channel *
791 *************************************************/
793 /* This is a separate function so that we don't have to repeat everything for
794 TLS support or debugging. It is global so that the daemon and the
795 authentication functions can use it. It does not return any error indication,
796 because major problems such as dropped connections won't show up till an output
797 flush for non-TLS connections. The smtp_fflush() function is available for
798 checking that: for convenience, TLS output errors are remembered here so that
799 they are also picked up later by smtp_fflush().
803 more further data expected
804 ... optional arguments
810 smtp_printf(const char *format, BOOL more, ...)
815 smtp_vprintf(format, more, ap);
819 /* This is split off so that verify.c:respond_printf() can, in effect, call
820 smtp_printf(), bearing in mind that in C a vararg function can't directly
821 call another vararg function, only a function which accepts a va_list. */
824 smtp_vprintf(const char *format, BOOL more, va_list ap)
828 yield = string_vformat(big_buffer, big_buffer_size, format, ap);
832 void *reset_point = store_get(0);
833 uschar *msg_copy, *cr, *end;
834 msg_copy = string_copy(big_buffer);
835 end = msg_copy + Ustrlen(msg_copy);
836 while ((cr = Ustrchr(msg_copy, '\r')) != NULL) /* lose CRs */
837 memmove(cr, cr + 1, (end--) - cr);
838 debug_printf("SMTP>> %s", msg_copy);
839 store_reset(reset_point);
844 log_write(0, LOG_MAIN|LOG_PANIC, "string too large in smtp_printf()");
845 smtp_closedown(US"Unexpected error");
846 exim_exit(EXIT_FAILURE, NULL);
849 /* If this is the first output for a (non-batch) RCPT command, see if all RCPTs
850 have had the same. Note: this code is also present in smtp_respond(). It would
851 be tidier to have it only in one place, but when it was added, it was easier to
852 do it that way, so as not to have to mess with the code for the RCPT command,
853 which sometimes uses smtp_printf() and sometimes smtp_respond(). */
855 if (rcpt_in_progress)
857 if (rcpt_smtp_response == NULL)
858 rcpt_smtp_response = string_copy(big_buffer);
859 else if (rcpt_smtp_response_same &&
860 Ustrcmp(rcpt_smtp_response, big_buffer) != 0)
861 rcpt_smtp_response_same = FALSE;
862 rcpt_in_progress = FALSE;
865 /* Now write the string */
868 if (tls_in.active >= 0)
870 if (tls_write(TRUE, big_buffer, Ustrlen(big_buffer), more) < 0)
871 smtp_write_error = -1;
876 if (fprintf(smtp_out, "%s", big_buffer) < 0) smtp_write_error = -1;
881 /*************************************************
882 * Flush SMTP out and check for error *
883 *************************************************/
885 /* This function isn't currently used within Exim (it detects errors when it
886 tries to read the next SMTP input), but is available for use in local_scan().
887 For non-TLS connections, it flushes the output and checks for errors. For
888 TLS-connections, it checks for a previously-detected TLS write error.
891 Returns: 0 for no error; -1 after an error
897 if (tls_in.active < 0 && fflush(smtp_out) != 0) smtp_write_error = -1;
898 return smtp_write_error;
903 /*************************************************
904 * SMTP command read timeout *
905 *************************************************/
907 /* Signal handler for timing out incoming SMTP commands. This attempts to
910 Argument: signal number (SIGALRM)
915 command_timeout_handler(int sig)
917 sig = sig; /* Keep picky compilers happy */
918 log_write(L_lost_incoming_connection,
919 LOG_MAIN, "SMTP command timeout on%s connection from %s",
920 (tls_in.active >= 0)? " TLS" : "",
921 host_and_ident(FALSE));
922 if (smtp_batched_input)
923 moan_smtp_batch(NULL, "421 SMTP command timeout"); /* Does not return */
924 smtp_notquit_exit(US"command-timeout", US"421",
925 US"%s: SMTP command timeout - closing connection", smtp_active_hostname);
926 exim_exit(EXIT_FAILURE, US"receiving");
931 /*************************************************
933 *************************************************/
935 /* Signal handler for handling SIGTERM. Again, try to finish tidily.
937 Argument: signal number (SIGTERM)
942 command_sigterm_handler(int sig)
944 sig = sig; /* Keep picky compilers happy */
945 log_write(0, LOG_MAIN, "%s closed after SIGTERM", smtp_get_connection_info());
946 if (smtp_batched_input)
947 moan_smtp_batch(NULL, "421 SIGTERM received"); /* Does not return */
948 smtp_notquit_exit(US"signal-exit", US"421",
949 US"%s: Service not available - closing connection", smtp_active_hostname);
950 exim_exit(EXIT_FAILURE, US"receiving");
957 /*************************************************
958 * Restore socket timeout to previous value *
959 *************************************************/
960 /* If the previous value was successfully retrieved, restore
961 it before returning control to the non-proxy routines
963 Arguments: fd - File descriptor for input
964 get_ok - Successfully retrieved previous values
965 tvtmp - Time struct with previous values
966 vslen - Length of time struct
970 restore_socket_timeout(int fd, int get_ok, struct timeval * tvtmp, socklen_t vslen)
973 (void) setsockopt(fd, SOL_SOCKET, SO_RCVTIMEO, CS tvtmp, vslen);
976 /*************************************************
977 * Check if host is required proxy host *
978 *************************************************/
979 /* The function determines if inbound host will be a regular smtp host
980 or if it is configured that it must use Proxy Protocol. A local
988 check_proxy_protocol_host()
992 if ( sender_host_address
993 && (rc = verify_check_this_host(CUSS &hosts_proxy, NULL, NULL,
994 sender_host_address, NULL)) == OK)
997 debug_printf("Detected proxy protocol configured host\n");
998 proxy_session = TRUE;
1000 return proxy_session;
1004 /*************************************************
1005 * Read data until newline or end of buffer *
1006 *************************************************/
1007 /* While SMTP is server-speaks-first, TLS is client-speaks-first, so we can't
1008 read an entire buffer and assume there will be nothing past a proxy protocol
1009 header. Our approach normally is to use stdio, but again that relies upon
1010 "STARTTLS\r\n" and a server response before the client starts TLS handshake, or
1011 reading _nothing_ before client TLS handshake. So we don't want to use the
1012 usual buffering reads which may read enough to block TLS starting.
1014 So unfortunately we're down to "read one byte at a time, with a syscall each,
1015 and expect a little overhead", for all proxy-opened connections which are v1,
1016 just to handle the TLS-on-connect case. Since SSL functions wrap the
1017 underlying fd, we can't assume that we can feed them any already-read content.
1019 We need to know where to read to, the max capacity, and we'll read until we
1020 get a CR and one more character. Let the caller scream if it's CR+!LF.
1022 Return the amount read.
1026 swallow_until_crlf(int fd, uschar *base, int already, int capacity)
1028 uschar *to = base + already;
1034 /* For "PROXY UNKNOWN\r\n" we, at time of writing, expect to have read
1035 up through the \r; for the _normal_ case, we haven't yet seen the \r. */
1037 cr = memchr(base, '\r', already);
1040 if ((cr - base) < already - 1)
1042 /* \r and presumed \n already within what we have; probably not
1043 actually proxy protocol, but abort cleanly. */
1046 /* \r is last character read, just need one more. */
1050 while (capacity > 0)
1052 do { ret = recv(fd, to, 1, 0); } while (ret == -1 && errno == EINTR);
1064 /* reached end without having room for a final newline, abort */
1069 /*************************************************
1070 * Setup host for proxy protocol *
1071 *************************************************/
1072 /* The function configures the connection based on a header from the
1073 inbound host to use Proxy Protocol. The specification is very exact
1074 so exit with an error if do not find the exact required pieces. This
1075 includes an incorrect number of spaces separating args.
1078 Returns: Boolean success
1082 setup_proxy_protocol_host()
1094 struct { /* TCP/UDP over IPv4, len = 12 */
1100 struct { /* TCP/UDP over IPv6, len = 36 */
1101 uint8_t src_addr[16];
1102 uint8_t dst_addr[16];
1106 struct { /* AF_UNIX sockets, len = 216 */
1107 uschar src_addr[108];
1108 uschar dst_addr[108];
1114 /* Temp variables used in PPv2 address:port parsing */
1116 char tmpip[INET_ADDRSTRLEN];
1117 struct sockaddr_in tmpaddr;
1118 char tmpip6[INET6_ADDRSTRLEN];
1119 struct sockaddr_in6 tmpaddr6;
1121 /* We can't read "all data until end" because while SMTP is
1122 server-speaks-first, the TLS handshake is client-speaks-first, so for
1123 TLS-on-connect ports the proxy protocol header will usually be immediately
1124 followed by a TLS handshake, and with N TLS libraries, we can't reliably
1125 reinject data for reading by those. So instead we first read "enough to be
1126 safely read within the header, and figure out how much more to read".
1127 For v1 we will later read to the end-of-line, for v2 we will read based upon
1130 The v2 sig is 12 octets, and another 4 gets us the length, so we know how much
1131 data is needed total. For v1, where the line looks like:
1132 PROXY TCPn L3src L3dest SrcPort DestPort \r\n
1134 However, for v1 there's also `PROXY UNKNOWN\r\n` which is only 15 octets.
1135 We seem to support that. So, if we read 14 octets then we can tell if we're
1136 v2 or v1. If we're v1, we can continue reading as normal.
1138 If we're v2, we can't slurp up the entire header. We need the length in the
1139 15th & 16th octets, then to read everything after that.
1141 So to safely handle v1 and v2, with client-sent-first supported correctly,
1142 we have to do a minimum of 3 read calls, not 1. Eww.
1145 #define PROXY_INITIAL_READ 14
1146 #define PROXY_V2_HEADER_SIZE 16
1147 #if PROXY_INITIAL_READ > PROXY_V2_HEADER_SIZE
1148 # error Code bug in sizes of data to read for proxy usage
1153 int fd = fileno(smtp_in);
1154 const char v2sig[12] = "\x0D\x0A\x0D\x0A\x00\x0D\x0A\x51\x55\x49\x54\x0A";
1155 uschar * iptype; /* To display debug info */
1157 struct timeval tvtmp;
1158 socklen_t vslen = sizeof(struct timeval);
1161 /* Save current socket timeout values */
1162 get_ok = getsockopt(fd, SOL_SOCKET, SO_RCVTIMEO, CS &tvtmp, &vslen);
1164 /* Proxy Protocol host must send header within a short time
1165 (default 3 seconds) or it's considered invalid */
1166 tv.tv_sec = PROXY_NEGOTIATION_TIMEOUT_SEC;
1167 tv.tv_usec = PROXY_NEGOTIATION_TIMEOUT_USEC;
1168 if (setsockopt(fd, SOL_SOCKET, SO_RCVTIMEO, CS &tv, sizeof(tv)) < 0)
1173 /* The inbound host was declared to be a Proxy Protocol host, so
1174 don't do a PEEK into the data, actually slurp up enough to be
1175 "safe". Can't take it all because TLS-on-connect clients follow
1176 immediately with TLS handshake. */
1177 ret = recv(fd, &hdr, PROXY_INITIAL_READ, 0);
1179 while (ret == -1 && errno == EINTR);
1184 /* For v2, handle reading the length, and then the rest. */
1185 if ((ret == PROXY_INITIAL_READ) && (memcmp(&hdr.v2, v2sig, sizeof(v2sig)) == 0))
1190 /* First get the length fields. */
1193 retmore = recv(fd, (uschar*)&hdr + ret, PROXY_V2_HEADER_SIZE - PROXY_INITIAL_READ, 0);
1194 } while (retmore == -1 && errno == EINTR);
1199 ver = (hdr.v2.ver_cmd & 0xf0) >> 4;
1201 /* May 2014: haproxy combined the version and command into one byte to
1202 allow two full bytes for the length field in order to proxy SSL
1203 connections. SSL Proxy is not supported in this version of Exim, but
1204 must still separate values here. */
1208 DEBUG(D_receive) debug_printf("Invalid Proxy Protocol version: %d\n", ver);
1212 /* The v2 header will always be 16 bytes per the spec. */
1213 size = 16 + ntohs(hdr.v2.len);
1214 DEBUG(D_receive) debug_printf("Detected PROXYv2 header, size %d (limit %d)\n",
1215 size, (int)sizeof(hdr));
1217 /* We should now have 16 octets (PROXY_V2_HEADER_SIZE), and we know the total
1218 amount that we need. Double-check that the size is not unreasonable, then
1220 if (size > sizeof(hdr))
1222 DEBUG(D_receive) debug_printf("PROXYv2 header size unreasonably large; security attack?\n");
1230 retmore = recv(fd, (uschar*)&hdr + ret, size-ret, 0);
1231 } while (retmore == -1 && errno == EINTR);
1235 DEBUG(D_receive) debug_printf("PROXYv2: have %d/%d required octets\n", ret, size);
1236 } while (ret < size);
1238 } /* end scope for getting rest of data for v2 */
1240 /* At this point: if PROXYv2, we've read the exact size required for all data;
1241 if PROXYv1 then we've read "less than required for any valid line" and should
1244 if (ret >= 16 && memcmp(&hdr.v2, v2sig, 12) == 0)
1246 uint8_t cmd = (hdr.v2.ver_cmd & 0x0f);
1250 case 0x01: /* PROXY command */
1253 case 0x11: /* TCPv4 address type */
1255 tmpaddr.sin_addr.s_addr = hdr.v2.addr.ip4.src_addr;
1256 inet_ntop(AF_INET, &tmpaddr.sin_addr, CS &tmpip, sizeof(tmpip));
1257 if (!string_is_ip_address(US tmpip, NULL))
1259 DEBUG(D_receive) debug_printf("Invalid %s source IP\n", iptype);
1262 proxy_local_address = sender_host_address;
1263 sender_host_address = string_copy(US tmpip);
1264 tmpport = ntohs(hdr.v2.addr.ip4.src_port);
1265 proxy_local_port = sender_host_port;
1266 sender_host_port = tmpport;
1267 /* Save dest ip/port */
1268 tmpaddr.sin_addr.s_addr = hdr.v2.addr.ip4.dst_addr;
1269 inet_ntop(AF_INET, &tmpaddr.sin_addr, CS &tmpip, sizeof(tmpip));
1270 if (!string_is_ip_address(US tmpip, NULL))
1272 DEBUG(D_receive) debug_printf("Invalid %s dest port\n", iptype);
1275 proxy_external_address = string_copy(US tmpip);
1276 tmpport = ntohs(hdr.v2.addr.ip4.dst_port);
1277 proxy_external_port = tmpport;
1279 case 0x21: /* TCPv6 address type */
1281 memmove(tmpaddr6.sin6_addr.s6_addr, hdr.v2.addr.ip6.src_addr, 16);
1282 inet_ntop(AF_INET6, &tmpaddr6.sin6_addr, CS &tmpip6, sizeof(tmpip6));
1283 if (!string_is_ip_address(US tmpip6, NULL))
1285 DEBUG(D_receive) debug_printf("Invalid %s source IP\n", iptype);
1288 proxy_local_address = sender_host_address;
1289 sender_host_address = string_copy(US tmpip6);
1290 tmpport = ntohs(hdr.v2.addr.ip6.src_port);
1291 proxy_local_port = sender_host_port;
1292 sender_host_port = tmpport;
1293 /* Save dest ip/port */
1294 memmove(tmpaddr6.sin6_addr.s6_addr, hdr.v2.addr.ip6.dst_addr, 16);
1295 inet_ntop(AF_INET6, &tmpaddr6.sin6_addr, CS &tmpip6, sizeof(tmpip6));
1296 if (!string_is_ip_address(US tmpip6, NULL))
1298 DEBUG(D_receive) debug_printf("Invalid %s dest port\n", iptype);
1301 proxy_external_address = string_copy(US tmpip6);
1302 tmpport = ntohs(hdr.v2.addr.ip6.dst_port);
1303 proxy_external_port = tmpport;
1307 debug_printf("Unsupported PROXYv2 connection type: 0x%02x\n",
1311 /* Unsupported protocol, keep local connection address */
1313 case 0x00: /* LOCAL command */
1314 /* Keep local connection address for LOCAL */
1319 debug_printf("Unsupported PROXYv2 command: 0x%x\n", cmd);
1323 else if (ret >= 8 && memcmp(hdr.v1.line, "PROXY", 5) == 0)
1327 uschar *sp; /* Utility variables follow */
1332 /* get the rest of the line */
1333 r2 = swallow_until_crlf(fd, (uschar*)&hdr, ret, sizeof(hdr)-ret);
1338 p = string_copy(hdr.v1.line);
1339 end = memchr(p, '\r', ret - 1);
1341 if (!end || (end == (uschar*)&hdr + ret) || end[1] != '\n')
1343 DEBUG(D_receive) debug_printf("Partial or invalid PROXY header\n");
1346 *end = '\0'; /* Terminate the string */
1347 size = end + 2 - p; /* Skip header + CRLF */
1348 DEBUG(D_receive) debug_printf("Detected PROXYv1 header\n");
1349 DEBUG(D_receive) debug_printf("Bytes read not within PROXY header: %d\n", ret - size);
1350 /* Step through the string looking for the required fields. Ensure
1351 strict adherence to required formatting, exit for any error. */
1353 if (!isspace(*(p++)))
1355 DEBUG(D_receive) debug_printf("Missing space after PROXY command\n");
1358 if (!Ustrncmp(p, CCS"TCP4", 4))
1360 else if (!Ustrncmp(p,CCS"TCP6", 4))
1362 else if (!Ustrncmp(p,CCS"UNKNOWN", 7))
1364 iptype = US"Unknown";
1369 DEBUG(D_receive) debug_printf("Invalid TCP type\n");
1373 p += Ustrlen(iptype);
1374 if (!isspace(*(p++)))
1376 DEBUG(D_receive) debug_printf("Missing space after TCP4/6 command\n");
1379 /* Find the end of the arg */
1380 if ((sp = Ustrchr(p, ' ')) == NULL)
1383 debug_printf("Did not find proxied src %s\n", iptype);
1387 if(!string_is_ip_address(p, NULL))
1390 debug_printf("Proxied src arg is not an %s address\n", iptype);
1393 proxy_local_address = sender_host_address;
1394 sender_host_address = p;
1396 if ((sp = Ustrchr(p, ' ')) == NULL)
1399 debug_printf("Did not find proxy dest %s\n", iptype);
1403 if(!string_is_ip_address(p, NULL))
1406 debug_printf("Proxy dest arg is not an %s address\n", iptype);
1409 proxy_external_address = p;
1411 if ((sp = Ustrchr(p, ' ')) == NULL)
1413 DEBUG(D_receive) debug_printf("Did not find proxied src port\n");
1417 tmp_port = strtol(CCS p, &endc, 10);
1418 if (*endc || tmp_port == 0)
1421 debug_printf("Proxied src port '%s' not an integer\n", p);
1424 proxy_local_port = sender_host_port;
1425 sender_host_port = tmp_port;
1427 if ((sp = Ustrchr(p, '\0')) == NULL)
1429 DEBUG(D_receive) debug_printf("Did not find proxy dest port\n");
1432 tmp_port = strtol(CCS p, &endc, 10);
1433 if (*endc || tmp_port == 0)
1436 debug_printf("Proxy dest port '%s' not an integer\n", p);
1439 proxy_external_port = tmp_port;
1440 /* Already checked for /r /n above. Good V1 header received. */
1444 /* Wrong protocol */
1445 DEBUG(D_receive) debug_printf("Invalid proxy protocol version negotiation\n");
1446 (void) swallow_until_crlf(fd, (uschar*)&hdr, ret, sizeof(hdr)-ret);
1452 debug_printf("Valid %s sender from Proxy Protocol header\n", iptype);
1453 yield = proxy_session;
1455 /* Don't flush any potential buffer contents. Any input on proxyfail
1456 should cause a synchronization failure */
1459 restore_socket_timeout(fd, get_ok, &tvtmp, vslen);
1464 sender_host_name = NULL;
1465 (void) host_name_lookup();
1466 host_build_sender_fullhost();
1470 proxy_session_failed = TRUE;
1472 debug_printf("Failure to extract proxied host, only QUIT allowed\n");
1479 /*************************************************
1480 * Read one command line *
1481 *************************************************/
1483 /* Strictly, SMTP commands coming over the net are supposed to end with CRLF.
1484 There are sites that don't do this, and in any case internal SMTP probably
1485 should check only for LF. Consequently, we check here for LF only. The line
1486 ends up with [CR]LF removed from its end. If we get an overlong line, treat as
1487 an unknown command. The command is read into the global smtp_cmd_buffer so that
1488 it is available via $smtp_command.
1490 The character reading routine sets up a timeout for each block actually read
1491 from the input (which may contain more than one command). We set up a special
1492 signal handler that closes down the session on a timeout. Control does not
1493 return when it runs.
1496 check_sync if TRUE, check synchronization rules if global option is TRUE
1497 buffer_lim maximum to buffer in lower layer
1499 Returns: a code identifying the command (enumerated above)
1503 smtp_read_command(BOOL check_sync, unsigned buffer_lim)
1508 BOOL hadnull = FALSE;
1510 os_non_restarting_signal(SIGALRM, command_timeout_handler);
1512 while ((c = (receive_getc)(buffer_lim)) != '\n' && c != EOF)
1514 if (ptr >= SMTP_CMD_BUFFER_SIZE)
1516 os_non_restarting_signal(SIGALRM, sigalrm_handler);
1524 smtp_cmd_buffer[ptr++] = c;
1527 receive_linecount++; /* For BSMTP errors */
1528 os_non_restarting_signal(SIGALRM, sigalrm_handler);
1530 /* If hit end of file, return pseudo EOF command. Whether we have a
1531 part-line already read doesn't matter, since this is an error state. */
1533 if (c == EOF) return EOF_CMD;
1535 /* Remove any CR and white space at the end of the line, and terminate the
1538 while (ptr > 0 && isspace(smtp_cmd_buffer[ptr-1])) ptr--;
1539 smtp_cmd_buffer[ptr] = 0;
1541 DEBUG(D_receive) debug_printf("SMTP<< %s\n", smtp_cmd_buffer);
1543 /* NULLs are not allowed in SMTP commands */
1545 if (hadnull) return BADCHAR_CMD;
1547 /* Scan command list and return identity, having set the data pointer
1548 to the start of the actual data characters. Check for SMTP synchronization
1551 for (p = cmd_list; p < cmd_list_end; p++)
1553 #ifdef SUPPORT_PROXY
1554 /* Only allow QUIT command if Proxy Protocol parsing failed */
1555 if (proxy_session && proxy_session_failed && p->cmd != QUIT_CMD)
1559 && strncmpic(smtp_cmd_buffer, US p->name, p->len) == 0
1560 && ( smtp_cmd_buffer[p->len-1] == ':' /* "mail from:" or "rcpt to:" */
1561 || smtp_cmd_buffer[p->len] == 0
1562 || smtp_cmd_buffer[p->len] == ' '
1565 if (smtp_inptr < smtp_inend && /* Outstanding input */
1566 p->cmd < sync_cmd_limit && /* Command should sync */
1567 check_sync && /* Local flag set */
1568 smtp_enforce_sync && /* Global flag set */
1569 sender_host_address != NULL && /* Not local input */
1570 !sender_host_notsocket) /* Really is a socket */
1573 /* The variables $smtp_command and $smtp_command_argument point into the
1574 unmodified input buffer. A copy of the latter is taken for actual
1575 processing, so that it can be chopped up into separate parts if necessary,
1576 for example, when processing a MAIL command options such as SIZE that can
1577 follow the sender address. */
1579 smtp_cmd_argument = smtp_cmd_buffer + p->len;
1580 while (isspace(*smtp_cmd_argument)) smtp_cmd_argument++;
1581 Ustrcpy(smtp_data_buffer, smtp_cmd_argument);
1582 smtp_cmd_data = smtp_data_buffer;
1584 /* Count non-mail commands from those hosts that are controlled in this
1585 way. The default is all hosts. We don't waste effort checking the list
1586 until we get a non-mail command, but then cache the result to save checking
1587 again. If there's a DEFER while checking the host, assume it's in the list.
1589 Note that one instance of RSET, EHLO/HELO, and STARTTLS is allowed at the
1590 start of each incoming message by fiddling with the value in the table. */
1592 if (!p->is_mail_cmd)
1594 if (count_nonmail == TRUE_UNSET) count_nonmail =
1595 verify_check_host(&smtp_accept_max_nonmail_hosts) != FAIL;
1596 if (count_nonmail && ++nonmail_command_count > smtp_accept_max_nonmail)
1597 return TOO_MANY_NONMAIL_CMD;
1600 /* If there is data for a command that does not expect it, generate the
1603 return (p->has_arg || *smtp_cmd_data == 0)? p->cmd : BADARG_CMD;
1607 #ifdef SUPPORT_PROXY
1608 /* Only allow QUIT command if Proxy Protocol parsing failed */
1609 if (proxy_session && proxy_session_failed)
1610 return PROXY_FAIL_IGNORE_CMD;
1613 /* Enforce synchronization for unknown commands */
1615 if ( smtp_inptr < smtp_inend /* Outstanding input */
1616 && check_sync /* Local flag set */
1617 && smtp_enforce_sync /* Global flag set */
1618 && sender_host_address /* Not local input */
1619 && !sender_host_notsocket) /* Really is a socket */
1627 /*************************************************
1628 * Forced closedown of call *
1629 *************************************************/
1631 /* This function is called from log.c when Exim is dying because of a serious
1632 disaster, and also from some other places. If an incoming non-batched SMTP
1633 channel is open, it swallows the rest of the incoming message if in the DATA
1634 phase, sends the reply string, and gives an error to all subsequent commands
1635 except QUIT. The existence of an SMTP call is detected by the non-NULLness of
1639 message SMTP reply string to send, excluding the code
1645 smtp_closedown(uschar *message)
1647 if (!smtp_in || smtp_batched_input) return;
1648 receive_swallow_smtp();
1649 smtp_printf("421 %s\r\n", FALSE, message);
1651 for (;;) switch(smtp_read_command(FALSE, GETC_BUFFER_UNLIMITED))
1657 smtp_printf("221 %s closing connection\r\n", FALSE, smtp_active_hostname);
1662 smtp_printf("250 Reset OK\r\n", FALSE);
1666 smtp_printf("421 %s\r\n", FALSE, message);
1674 /*************************************************
1675 * Set up connection info for logging *
1676 *************************************************/
1678 /* This function is called when logging information about an SMTP connection.
1679 It sets up appropriate source information, depending on the type of connection.
1680 If sender_fullhost is NULL, we are at a very early stage of the connection;
1681 just use the IP address.
1684 Returns: a string describing the connection
1688 smtp_get_connection_info(void)
1690 const uschar * hostname = sender_fullhost
1691 ? sender_fullhost : sender_host_address;
1694 return string_sprintf("SMTP connection from %s", hostname);
1696 if (sender_host_unknown || sender_host_notsocket)
1697 return string_sprintf("SMTP connection from %s", sender_ident);
1700 return string_sprintf("SMTP connection from %s (via inetd)", hostname);
1702 if (LOGGING(incoming_interface) && interface_address != NULL)
1703 return string_sprintf("SMTP connection from %s I=[%s]:%d", hostname,
1704 interface_address, interface_port);
1706 return string_sprintf("SMTP connection from %s", hostname);
1712 /* Append TLS-related information to a log line
1715 g String under construction: allocated string to extend, or NULL
1717 Returns: Allocated string or NULL
1720 s_tlslog(gstring * g)
1722 if (LOGGING(tls_cipher) && tls_in.cipher)
1723 g = string_append(g, 2, US" X=", tls_in.cipher);
1724 if (LOGGING(tls_certificate_verified) && tls_in.cipher)
1725 g = string_append(g, 2, US" CV=", tls_in.certificate_verified? "yes":"no");
1726 if (LOGGING(tls_peerdn) && tls_in.peerdn)
1727 g = string_append(g, 3, US" DN=\"", string_printing(tls_in.peerdn), US"\"");
1728 if (LOGGING(tls_sni) && tls_in.sni)
1729 g = string_append(g, 3, US" SNI=\"", string_printing(tls_in.sni), US"\"");
1734 /*************************************************
1735 * Log lack of MAIL if so configured *
1736 *************************************************/
1738 /* This function is called when an SMTP session ends. If the log selector
1739 smtp_no_mail is set, write a log line giving some details of what has happened
1740 in the SMTP session.
1747 smtp_log_no_mail(void)
1753 if (smtp_mailcmd_count > 0 || !LOGGING(smtp_no_mail))
1756 if (sender_host_authenticated)
1758 g = string_append(g, 2, US" A=", sender_host_authenticated);
1759 if (authenticated_id) g = string_append(g, 2, US":", authenticated_id);
1766 sep = smtp_connection_had[SMTP_HBUFF_SIZE-1] != SCH_NONE ? US" C=..." : US" C=";
1768 for (i = smtp_ch_index; i < SMTP_HBUFF_SIZE; i++)
1769 if (smtp_connection_had[i] != SCH_NONE)
1771 g = string_append(g, 2, sep, smtp_names[smtp_connection_had[i]]);
1775 for (i = 0; i < smtp_ch_index; i++)
1777 g = string_append(g, 2, sep, smtp_names[smtp_connection_had[i]]);
1781 if (!(s = string_from_gstring(g))) s = US"";
1783 log_write(0, LOG_MAIN, "no MAIL in %sSMTP connection from %s D=%s%s",
1784 tcp_in_fastopen ? US"TFO " : US"",
1785 host_and_ident(FALSE), string_timesince(&smtp_connection_start), s);
1789 /* Return list of recent smtp commands */
1795 gstring * list = NULL;
1798 for (i = smtp_ch_index; i < SMTP_HBUFF_SIZE; i++)
1799 if (smtp_connection_had[i] != SCH_NONE)
1800 list = string_append_listele(list, ',', smtp_names[smtp_connection_had[i]]);
1802 for (i = 0; i < smtp_ch_index; i++)
1803 list = string_append_listele(list, ',', smtp_names[smtp_connection_had[i]]);
1805 s = string_from_gstring(list);
1806 return s ? s : US"";
1812 /*************************************************
1813 * Check HELO line and set sender_helo_name *
1814 *************************************************/
1816 /* Check the format of a HELO line. The data for HELO/EHLO is supposed to be
1817 the domain name of the sending host, or an ip literal in square brackets. The
1818 argument is placed in sender_helo_name, which is in malloc store, because it
1819 must persist over multiple incoming messages. If helo_accept_junk is set, this
1820 host is permitted to send any old junk (needed for some broken hosts).
1821 Otherwise, helo_allow_chars can be used for rogue characters in general
1822 (typically people want to let in underscores).
1825 s the data portion of the line (already past any white space)
1827 Returns: TRUE or FALSE
1831 check_helo(uschar *s)
1834 uschar *end = s + Ustrlen(s);
1835 BOOL yield = helo_accept_junk;
1837 /* Discard any previous helo name */
1839 if (sender_helo_name)
1841 store_free(sender_helo_name);
1842 sender_helo_name = NULL;
1845 /* Skip tests if junk is permitted. */
1849 /* Allow the new standard form for IPv6 address literals, namely,
1850 [IPv6:....], and because someone is bound to use it, allow an equivalent
1851 IPv4 form. Allow plain addresses as well. */
1858 if (strncmpic(s, US"[IPv6:", 6) == 0)
1859 yield = (string_is_ip_address(s+6, NULL) == 6);
1860 else if (strncmpic(s, US"[IPv4:", 6) == 0)
1861 yield = (string_is_ip_address(s+6, NULL) == 4);
1863 yield = (string_is_ip_address(s+1, NULL) != 0);
1868 /* Non-literals must be alpha, dot, hyphen, plus any non-valid chars
1869 that have been configured (usually underscore - sigh). */
1872 for (yield = TRUE; *s; s++)
1873 if (!isalnum(*s) && *s != '.' && *s != '-' &&
1874 Ustrchr(helo_allow_chars, *s) == NULL)
1880 /* Save argument if OK */
1882 if (yield) sender_helo_name = string_copy_malloc(start);
1890 /*************************************************
1891 * Extract SMTP command option *
1892 *************************************************/
1894 /* This function picks the next option setting off the end of smtp_cmd_data. It
1895 is called for MAIL FROM and RCPT TO commands, to pick off the optional ESMTP
1896 things that can appear there.
1899 name point this at the name
1900 value point this at the data string
1902 Returns: TRUE if found an option
1906 extract_option(uschar **name, uschar **value)
1909 uschar *v = smtp_cmd_data + Ustrlen(smtp_cmd_data) - 1;
1910 while (isspace(*v)) v--;
1912 while (v > smtp_cmd_data && *v != '=' && !isspace(*v))
1914 /* Take care to not stop at a space embedded in a quoted local-part */
1916 if (*v == '"') do v--; while (*v != '"' && v > smtp_cmd_data+1);
1923 while(isalpha(n[-1])) n--;
1924 /* RFC says SP, but TAB seen in wild and other major MTAs accept it */
1925 if (!isspace(n[-1])) return FALSE;
1931 if (v == smtp_cmd_data) return FALSE;
1943 /*************************************************
1944 * Reset for new message *
1945 *************************************************/
1947 /* This function is called whenever the SMTP session is reset from
1948 within either of the setup functions; also from the daemon loop.
1950 Argument: the stacking pool storage reset point
1955 smtp_reset(void *reset_point)
1957 recipients_list = NULL;
1958 rcpt_count = rcpt_defer_count = rcpt_fail_count =
1959 raw_recipients_count = recipients_count = recipients_list_max = 0;
1960 message_linecount = 0;
1962 acl_added_headers = NULL;
1963 acl_removed_headers = NULL;
1964 queue_only_policy = FALSE;
1965 rcpt_smtp_response = NULL;
1966 rcpt_smtp_response_same = TRUE;
1967 rcpt_in_progress = FALSE;
1968 deliver_freeze = FALSE; /* Can be set by ACL */
1969 freeze_tell = freeze_tell_config; /* Can be set by ACL */
1970 fake_response = OK; /* Can be set by ACL */
1971 #ifdef WITH_CONTENT_SCAN
1972 no_mbox_unspool = FALSE; /* Can be set by ACL */
1974 submission_mode = FALSE; /* Can be set by ACL */
1975 suppress_local_fixups = suppress_local_fixups_default; /* Can be set by ACL */
1976 active_local_from_check = local_from_check; /* Can be set by ACL */
1977 active_local_sender_retain = local_sender_retain; /* Can be set by ACL */
1978 sending_ip_address = NULL;
1979 return_path = sender_address = NULL;
1980 sender_data = NULL; /* Can be set by ACL */
1981 deliver_localpart_parent = deliver_localpart_orig = NULL;
1982 deliver_domain_parent = deliver_domain_orig = NULL;
1983 callout_address = NULL;
1984 submission_name = NULL; /* Can be set by ACL */
1985 raw_sender = NULL; /* After SMTP rewrite, before qualifying */
1986 sender_address_unrewritten = NULL; /* Set only after verify rewrite */
1987 sender_verified_list = NULL; /* No senders verified */
1988 memset(sender_address_cache, 0, sizeof(sender_address_cache));
1989 memset(sender_domain_cache, 0, sizeof(sender_domain_cache));
1991 authenticated_sender = NULL;
1992 #ifdef EXPERIMENTAL_BRIGHTMAIL
1994 bmi_verdicts = NULL;
1996 dnslist_domain = dnslist_matched = NULL;
1997 #ifndef DISABLE_DKIM
1998 dkim_cur_signer = dkim_signers = NULL;
1999 dkim_disable_verify = dkim_collect_input = FALSE;
2003 deliver_host = deliver_host_address = NULL; /* Can be set by ACL */
2004 #ifndef DISABLE_PRDR
2005 prdr_requested = FALSE;
2008 spf_header_comment = spf_received = spf_result = spf_smtp_comment = NULL;
2010 #ifdef EXPERIMENTAL_DMARC
2011 dmarc_has_been_checked = dmarc_disable_verify = dmarc_enable_forensic = FALSE;
2012 dmarc_domain_policy = dmarc_forensic_sender =
2013 dmarc_history_file = dmarc_status = dmarc_status_text =
2014 dmarc_tld_file = dmarc_used_domain = NULL;
2016 #ifdef EXPERIMENTAL_ARC
2017 arc_state = arc_state_reason = NULL;
2020 message_smtputf8 = FALSE;
2022 body_linecount = body_zerocount = 0;
2024 sender_rate = sender_rate_limit = sender_rate_period = NULL;
2025 ratelimiters_mail = NULL; /* Updated by ratelimit ACL condition */
2026 /* Note that ratelimiters_conn persists across resets. */
2028 /* Reset message ACL variables */
2032 /* The message body variables use malloc store. They may be set if this is
2033 not the first message in an SMTP session and the previous message caused them
2034 to be referenced in an ACL. */
2038 store_free(message_body);
2039 message_body = NULL;
2042 if (message_body_end)
2044 store_free(message_body_end);
2045 message_body_end = NULL;
2048 /* Warning log messages are also saved in malloc store. They are saved to avoid
2049 repetition in the same message, but it seems right to repeat them for different
2052 while (acl_warn_logged)
2054 string_item *this = acl_warn_logged;
2055 acl_warn_logged = acl_warn_logged->next;
2058 store_reset(reset_point);
2065 /*************************************************
2066 * Initialize for incoming batched SMTP message *
2067 *************************************************/
2069 /* This function is called from smtp_setup_msg() in the case when
2070 smtp_batched_input is true. This happens when -bS is used to pass a whole batch
2071 of messages in one file with SMTP commands between them. All errors must be
2072 reported by sending a message, and only MAIL FROM, RCPT TO, and DATA are
2073 relevant. After an error on a sender, or an invalid recipient, the remainder
2074 of the message is skipped. The value of received_protocol is already set.
2077 Returns: > 0 message successfully started (reached DATA)
2078 = 0 QUIT read or end of file reached
2079 < 0 should not occur
2083 smtp_setup_batch_msg(void)
2086 void *reset_point = store_get(0);
2088 /* Save the line count at the start of each transaction - single commands
2089 like HELO and RSET count as whole transactions. */
2091 bsmtp_transaction_linecount = receive_linecount;
2093 if ((receive_feof)()) return 0; /* Treat EOF as QUIT */
2095 cancel_cutthrough_connection(TRUE, US"smtp_setup_batch_msg");
2096 smtp_reset(reset_point); /* Reset for start of message */
2098 /* Deal with SMTP commands. This loop is exited by setting done to a POSITIVE
2099 value. The values are 2 larger than the required yield of the function. */
2104 uschar *recipient = NULL;
2105 int start, end, sender_domain, recipient_domain;
2107 switch(smtp_read_command(FALSE, GETC_BUFFER_UNLIMITED))
2109 /* The HELO/EHLO commands set sender_address_helo if they have
2110 valid data; otherwise they are ignored, except that they do
2111 a reset of the state. */
2116 check_helo(smtp_cmd_data);
2120 cancel_cutthrough_connection(TRUE, US"RSET received");
2121 smtp_reset(reset_point);
2122 bsmtp_transaction_linecount = receive_linecount;
2126 /* The MAIL FROM command requires an address as an operand. All we
2127 do here is to parse it for syntactic correctness. The form "<>" is
2128 a special case which converts into an empty string. The start/end
2129 pointers in the original are not used further for this address, as
2130 it is the canonical extracted address which is all that is kept. */
2133 smtp_mailcmd_count++; /* Count for no-mail log */
2134 if (sender_address != NULL)
2135 /* The function moan_smtp_batch() does not return. */
2136 moan_smtp_batch(smtp_cmd_buffer, "503 Sender already given");
2138 if (smtp_cmd_data[0] == 0)
2139 /* The function moan_smtp_batch() does not return. */
2140 moan_smtp_batch(smtp_cmd_buffer, "501 MAIL FROM must have an address operand");
2142 /* Reset to start of message */
2144 cancel_cutthrough_connection(TRUE, US"MAIL received");
2145 smtp_reset(reset_point);
2147 /* Apply SMTP rewrite */
2149 raw_sender = ((rewrite_existflags & rewrite_smtp) != 0)?
2150 rewrite_one(smtp_cmd_data, rewrite_smtp|rewrite_smtp_sender, NULL, FALSE,
2151 US"", global_rewrite_rules) : smtp_cmd_data;
2153 /* Extract the address; the TRUE flag allows <> as valid */
2156 parse_extract_address(raw_sender, &errmess, &start, &end, &sender_domain,
2160 /* The function moan_smtp_batch() does not return. */
2161 moan_smtp_batch(smtp_cmd_buffer, "501 %s", errmess);
2163 sender_address = string_copy(raw_sender);
2165 /* Qualify unqualified sender addresses if permitted to do so. */
2168 && sender_address[0] != 0 && sender_address[0] != '@')
2169 if (allow_unqualified_sender)
2171 sender_address = rewrite_address_qualify(sender_address, FALSE);
2172 DEBUG(D_receive) debug_printf("unqualified address %s accepted "
2173 "and rewritten\n", raw_sender);
2175 /* The function moan_smtp_batch() does not return. */
2177 moan_smtp_batch(smtp_cmd_buffer, "501 sender address must contain "
2182 /* The RCPT TO command requires an address as an operand. All we do
2183 here is to parse it for syntactic correctness. There may be any number
2184 of RCPT TO commands, specifying multiple senders. We build them all into
2185 a data structure that is in argc/argv format. The start/end values
2186 given by parse_extract_address are not used, as we keep only the
2187 extracted address. */
2190 if (!sender_address)
2191 /* The function moan_smtp_batch() does not return. */
2192 moan_smtp_batch(smtp_cmd_buffer, "503 No sender yet given");
2194 if (smtp_cmd_data[0] == 0)
2195 /* The function moan_smtp_batch() does not return. */
2196 moan_smtp_batch(smtp_cmd_buffer,
2197 "501 RCPT TO must have an address operand");
2199 /* Check maximum number allowed */
2201 if (recipients_max > 0 && recipients_count + 1 > recipients_max)
2202 /* The function moan_smtp_batch() does not return. */
2203 moan_smtp_batch(smtp_cmd_buffer, "%s too many recipients",
2204 recipients_max_reject? "552": "452");
2206 /* Apply SMTP rewrite, then extract address. Don't allow "<>" as a
2207 recipient address */
2209 recipient = rewrite_existflags & rewrite_smtp
2210 ? rewrite_one(smtp_cmd_data, rewrite_smtp, NULL, FALSE, US"",
2211 global_rewrite_rules)
2214 recipient = parse_extract_address(recipient, &errmess, &start, &end,
2215 &recipient_domain, FALSE);
2218 /* The function moan_smtp_batch() does not return. */
2219 moan_smtp_batch(smtp_cmd_buffer, "501 %s", errmess);
2221 /* If the recipient address is unqualified, qualify it if permitted. Then
2222 add it to the list of recipients. */
2224 if (!recipient_domain)
2225 if (allow_unqualified_recipient)
2227 DEBUG(D_receive) debug_printf("unqualified address %s accepted\n",
2229 recipient = rewrite_address_qualify(recipient, TRUE);
2231 /* The function moan_smtp_batch() does not return. */
2233 moan_smtp_batch(smtp_cmd_buffer,
2234 "501 recipient address must contain a domain");
2236 receive_add_recipient(recipient, -1);
2240 /* The DATA command is legal only if it follows successful MAIL FROM
2241 and RCPT TO commands. This function is complete when a valid DATA
2242 command is encountered. */
2245 if (!sender_address || recipients_count <= 0)
2246 /* The function moan_smtp_batch() does not return. */
2247 if (!sender_address)
2248 moan_smtp_batch(smtp_cmd_buffer,
2249 "503 MAIL FROM:<sender> command must precede DATA");
2251 moan_smtp_batch(smtp_cmd_buffer,
2252 "503 RCPT TO:<recipient> must precede DATA");
2255 done = 3; /* DATA successfully achieved */
2256 message_ended = END_NOTENDED; /* Indicate in middle of message */
2261 /* The VRFY, EXPN, HELP, ETRN, and NOOP commands are ignored. */
2268 bsmtp_transaction_linecount = receive_linecount;
2279 /* The function moan_smtp_batch() does not return. */
2280 moan_smtp_batch(smtp_cmd_buffer, "501 Unexpected argument data");
2285 /* The function moan_smtp_batch() does not return. */
2286 moan_smtp_batch(smtp_cmd_buffer, "501 Unexpected NULL in SMTP command");
2291 /* The function moan_smtp_batch() does not return. */
2292 moan_smtp_batch(smtp_cmd_buffer, "500 Command unrecognized");
2297 return done - 2; /* Convert yield values */
2304 smtp_log_tls_fail(uschar * errstr)
2306 uschar * conn_info = smtp_get_connection_info();
2308 if (Ustrncmp(conn_info, US"SMTP ", 5) == 0) conn_info += 5;
2309 /* I'd like to get separated H= here, but too hard for now */
2311 log_write(0, LOG_MAIN, "TLS error on %s %s", conn_info, errstr);
2323 struct tcp_info tinfo;
2324 socklen_t len = sizeof(tinfo);
2326 if ( getsockopt(fileno(smtp_out), IPPROTO_TCP, TCP_INFO, &tinfo, &len) == 0
2327 && tinfo.tcpi_state == TCP_SYN_RECV
2330 DEBUG(D_receive) debug_printf("TCP_FASTOPEN mode connection (state TCP_SYN_RECV)\n");
2331 tcp_in_fastopen = TRUE;
2338 /*************************************************
2339 * Start an SMTP session *
2340 *************************************************/
2342 /* This function is called at the start of an SMTP session. Thereafter,
2343 smtp_setup_msg() is called to initiate each separate message. This
2344 function does host-specific testing, and outputs the banner line.
2347 Returns: FALSE if the session can not continue; something has
2348 gone wrong, or the connection to the host is blocked
2352 smtp_start_session(void)
2355 uschar *user_msg, *log_msg;
2360 gettimeofday(&smtp_connection_start, NULL);
2361 for (smtp_ch_index = 0; smtp_ch_index < SMTP_HBUFF_SIZE; smtp_ch_index++)
2362 smtp_connection_had[smtp_ch_index] = SCH_NONE;
2365 /* Default values for certain variables */
2367 helo_seen = esmtp = helo_accept_junk = FALSE;
2368 smtp_mailcmd_count = 0;
2369 count_nonmail = TRUE_UNSET;
2370 synprot_error_count = unknown_command_count = nonmail_command_count = 0;
2371 smtp_delay_mail = smtp_rlm_base;
2372 auth_advertised = FALSE;
2373 pipelining_advertised = FALSE;
2374 pipelining_enable = TRUE;
2375 sync_cmd_limit = NON_SYNC_CMD_NON_PIPELINING;
2376 smtp_exit_function_called = FALSE; /* For avoiding loop in not-quit exit */
2378 /* If receiving by -bs from a trusted user, or testing with -bh, we allow
2379 authentication settings from -oMaa to remain in force. */
2381 if (!host_checking && !sender_host_notsocket)
2382 sender_host_auth_pubname = sender_host_authenticated = NULL;
2383 authenticated_by = NULL;
2386 tls_in.cipher = tls_in.peerdn = NULL;
2387 tls_in.ourcert = tls_in.peercert = NULL;
2389 tls_in.ocsp = OCSP_NOT_REQ;
2390 tls_advertised = FALSE;
2392 dsn_advertised = FALSE;
2394 smtputf8_advertised = FALSE;
2397 /* Reset ACL connection variables */
2401 /* Allow for trailing 0 in the command and data buffers. */
2403 if (!(smtp_cmd_buffer = US malloc(2*SMTP_CMD_BUFFER_SIZE + 2)))
2404 log_write(0, LOG_MAIN|LOG_PANIC_DIE,
2405 "malloc() failed for SMTP command buffer");
2407 smtp_cmd_buffer[0] = 0;
2408 smtp_data_buffer = smtp_cmd_buffer + SMTP_CMD_BUFFER_SIZE + 1;
2410 /* For batched input, the protocol setting can be overridden from the
2411 command line by a trusted caller. */
2413 if (smtp_batched_input)
2415 if (!received_protocol) received_protocol = US"local-bsmtp";
2418 /* For non-batched SMTP input, the protocol setting is forced here. It will be
2419 reset later if any of EHLO/AUTH/STARTTLS are received. */
2423 (sender_host_address ? protocols : protocols_local) [pnormal];
2425 /* Set up the buffer for inputting using direct read() calls, and arrange to
2426 call the local functions instead of the standard C ones. Place a NUL at the
2427 end of the buffer to safety-stop C-string reads from it. */
2429 if (!(smtp_inbuffer = US malloc(IN_BUFFER_SIZE)))
2430 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "malloc() failed for SMTP input buffer");
2431 smtp_inbuffer[IN_BUFFER_SIZE-1] = '\0';
2433 receive_getc = smtp_getc;
2434 receive_getbuf = smtp_getbuf;
2435 receive_get_cache = smtp_get_cache;
2436 receive_ungetc = smtp_ungetc;
2437 receive_feof = smtp_feof;
2438 receive_ferror = smtp_ferror;
2439 receive_smtp_buffered = smtp_buffered;
2440 smtp_inptr = smtp_inend = smtp_inbuffer;
2441 smtp_had_eof = smtp_had_error = 0;
2443 /* Set up the message size limit; this may be host-specific */
2445 thismessage_size_limit = expand_string_integer(message_size_limit, TRUE);
2446 if (expand_string_message)
2448 if (thismessage_size_limit == -1)
2449 log_write(0, LOG_MAIN|LOG_PANIC, "unable to expand message_size_limit: "
2450 "%s", expand_string_message);
2452 log_write(0, LOG_MAIN|LOG_PANIC, "invalid message_size_limit: "
2453 "%s", expand_string_message);
2454 smtp_closedown(US"Temporary local problem - please try later");
2458 /* When a message is input locally via the -bs or -bS options, sender_host_
2459 unknown is set unless -oMa was used to force an IP address, in which case it
2460 is checked like a real remote connection. When -bs is used from inetd, this
2461 flag is not set, causing the sending host to be checked. The code that deals
2462 with IP source routing (if configured) is never required for -bs or -bS and
2463 the flag sender_host_notsocket is used to suppress it.
2465 If smtp_accept_max and smtp_accept_reserve are set, keep some connections in
2466 reserve for certain hosts and/or networks. */
2468 if (!sender_host_unknown)
2471 BOOL reserved_host = FALSE;
2473 /* Look up IP options (source routing info) on the socket if this is not an
2474 -oMa "host", and if any are found, log them and drop the connection.
2476 Linux (and others now, see below) is different to everyone else, so there
2477 has to be some conditional compilation here. Versions of Linux before 2.1.15
2478 used a structure whose name was "options". Somebody finally realized that
2479 this name was silly, and it got changed to "ip_options". I use the
2480 newer name here, but there is a fudge in the script that sets up os.h
2481 to define a macro in older Linux systems.
2483 Sigh. Linux is a fast-moving target. Another generation of Linux uses
2484 glibc 2, which has chosen ip_opts for the structure name. This is now
2485 really a glibc thing rather than a Linux thing, so the condition name
2486 has been changed to reflect this. It is relevant also to GNU/Hurd.
2488 Mac OS 10.x (Darwin) is like the later glibc versions, but without the
2489 setting of the __GLIBC__ macro, so we can't detect it automatically. There's
2490 a special macro defined in the os.h file.
2492 Some DGUX versions on older hardware appear not to support IP options at
2493 all, so there is now a general macro which can be set to cut out this
2496 How to do this properly in IPv6 is not yet known. */
2498 #if !HAVE_IPV6 && !defined(NO_IP_OPTIONS)
2500 #ifdef GLIBC_IP_OPTIONS
2501 #if (!defined __GLIBC__) || (__GLIBC__ < 2)
2506 #elif defined DARWIN_IP_OPTIONS
2512 if (!host_checking && !sender_host_notsocket)
2515 EXIM_SOCKLEN_T optlen = sizeof(struct ip_options) + MAX_IPOPTLEN;
2516 struct ip_options *ipopt = store_get(optlen);
2518 struct ip_opts ipoptblock;
2519 struct ip_opts *ipopt = &ipoptblock;
2520 EXIM_SOCKLEN_T optlen = sizeof(ipoptblock);
2522 struct ipoption ipoptblock;
2523 struct ipoption *ipopt = &ipoptblock;
2524 EXIM_SOCKLEN_T optlen = sizeof(ipoptblock);
2527 /* Occasional genuine failures of getsockopt() have been seen - for
2528 example, "reset by peer". Therefore, just log and give up on this
2529 call, unless the error is ENOPROTOOPT. This error is given by systems
2530 that have the interfaces but not the mechanism - e.g. GNU/Hurd at the time
2531 of writing. So for that error, carry on - we just can't do an IP options
2534 DEBUG(D_receive) debug_printf("checking for IP options\n");
2536 if (getsockopt(fileno(smtp_out), IPPROTO_IP, IP_OPTIONS, US (ipopt),
2539 if (errno != ENOPROTOOPT)
2541 log_write(0, LOG_MAIN, "getsockopt() failed from %s: %s",
2542 host_and_ident(FALSE), strerror(errno));
2543 smtp_printf("451 SMTP service not available\r\n", FALSE);
2548 /* Deal with any IP options that are set. On the systems I have looked at,
2549 the value of MAX_IPOPTLEN has been 40, meaning that there should never be
2550 more logging data than will fit in big_buffer. Nevertheless, after somebody
2551 questioned this code, I've added in some paranoid checking. */
2553 else if (optlen > 0)
2555 uschar *p = big_buffer;
2556 uschar *pend = big_buffer + big_buffer_size;
2557 uschar *opt, *adptr;
2559 struct in_addr addr;
2562 uschar *optstart = US (ipopt->__data);
2564 uschar *optstart = US (ipopt->ip_opts);
2566 uschar *optstart = US (ipopt->ipopt_list);
2569 DEBUG(D_receive) debug_printf("IP options exist\n");
2571 Ustrcpy(p, "IP options on incoming call:");
2574 for (opt = optstart; opt != NULL &&
2575 opt < US (ipopt) + optlen;)
2589 if (!string_format(p, pend-p, " %s [@%s",
2590 (*opt == IPOPT_SSRR)? "SSRR" : "LSRR",
2592 inet_ntoa(*((struct in_addr *)(&(ipopt->faddr))))))
2594 inet_ntoa(ipopt->ip_dst)))
2596 inet_ntoa(ipopt->ipopt_dst)))
2604 optcount = (opt[1] - 3) / sizeof(struct in_addr);
2606 while (optcount-- > 0)
2608 memcpy(&addr, adptr, sizeof(addr));
2609 if (!string_format(p, pend - p - 1, "%s%s",
2610 (optcount == 0)? ":" : "@", inet_ntoa(addr)))
2616 adptr += sizeof(struct in_addr);
2625 if (pend - p < 4 + 3*opt[1]) { opt = NULL; break; }
2628 for (i = 0; i < opt[1]; i++)
2629 p += sprintf(CS p, "%2.2x ", opt[i]);
2638 log_write(0, LOG_MAIN, "%s", big_buffer);
2640 /* Refuse any call with IP options. This is what tcpwrappers 7.5 does. */
2642 log_write(0, LOG_MAIN|LOG_REJECT,
2643 "connection from %s refused (IP options)", host_and_ident(FALSE));
2645 smtp_printf("554 SMTP service not available\r\n", FALSE);
2649 /* Length of options = 0 => there are no options */
2651 else DEBUG(D_receive) debug_printf("no IP options found\n");
2653 #endif /* HAVE_IPV6 && !defined(NO_IP_OPTIONS) */
2655 /* Set keep-alive in socket options. The option is on by default. This
2656 setting is an attempt to get rid of some hanging connections that stick in
2657 read() when the remote end (usually a dialup) goes away. */
2659 if (smtp_accept_keepalive && !sender_host_notsocket)
2660 ip_keepalive(fileno(smtp_out), sender_host_address, FALSE);
2662 /* If the current host matches host_lookup, set the name by doing a
2663 reverse lookup. On failure, sender_host_name will be NULL and
2664 host_lookup_failed will be TRUE. This may or may not be serious - optional
2667 if (verify_check_host(&host_lookup) == OK)
2669 (void)host_name_lookup();
2670 host_build_sender_fullhost();
2673 /* Delay this until we have the full name, if it is looked up. */
2675 set_process_info("handling incoming connection from %s",
2676 host_and_ident(FALSE));
2678 /* Expand smtp_receive_timeout, if needed */
2680 if (smtp_receive_timeout_s)
2683 if ( !(exp = expand_string(smtp_receive_timeout_s))
2685 || (smtp_receive_timeout = readconf_readtime(exp, 0, FALSE)) < 0
2687 log_write(0, LOG_MAIN|LOG_PANIC,
2688 "bad value for smtp_receive_timeout: '%s'", exp ? exp : US"");
2691 /* Test for explicit connection rejection */
2693 if (verify_check_host(&host_reject_connection) == OK)
2695 log_write(L_connection_reject, LOG_MAIN|LOG_REJECT, "refused connection "
2696 "from %s (host_reject_connection)", host_and_ident(FALSE));
2697 smtp_printf("554 SMTP service not available\r\n", FALSE);
2701 /* Test with TCP Wrappers if so configured. There is a problem in that
2702 hosts_ctl() returns 0 (deny) under a number of system failure circumstances,
2703 such as disks dying. In these cases, it is desirable to reject with a 4xx
2704 error instead of a 5xx error. There isn't a "right" way to detect such
2705 problems. The following kludge is used: errno is zeroed before calling
2706 hosts_ctl(). If the result is "reject", a 5xx error is given only if the
2707 value of errno is 0 or ENOENT (which happens if /etc/hosts.{allow,deny} does
2710 #ifdef USE_TCP_WRAPPERS
2712 if (!(tcp_wrappers_name = expand_string(tcp_wrappers_daemon_name)))
2713 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "Expansion of \"%s\" "
2714 "(tcp_wrappers_name) failed: %s", string_printing(tcp_wrappers_name),
2715 expand_string_message);
2717 if (!hosts_ctl(tcp_wrappers_name,
2718 sender_host_name ? CS sender_host_name : STRING_UNKNOWN,
2719 sender_host_address ? CS sender_host_address : STRING_UNKNOWN,
2720 sender_ident ? CS sender_ident : STRING_UNKNOWN))
2722 if (errno == 0 || errno == ENOENT)
2724 HDEBUG(D_receive) debug_printf("tcp wrappers rejection\n");
2725 log_write(L_connection_reject,
2726 LOG_MAIN|LOG_REJECT, "refused connection from %s "
2727 "(tcp wrappers)", host_and_ident(FALSE));
2728 smtp_printf("554 SMTP service not available\r\n", FALSE);
2732 int save_errno = errno;
2733 HDEBUG(D_receive) debug_printf("tcp wrappers rejected with unexpected "
2734 "errno value %d\n", save_errno);
2735 log_write(L_connection_reject,
2736 LOG_MAIN|LOG_REJECT, "temporarily refused connection from %s "
2737 "(tcp wrappers errno=%d)", host_and_ident(FALSE), save_errno);
2738 smtp_printf("451 Temporary local problem - please try later\r\n", FALSE);
2744 /* Check for reserved slots. The value of smtp_accept_count has already been
2745 incremented to include this process. */
2747 if (smtp_accept_max > 0 &&
2748 smtp_accept_count > smtp_accept_max - smtp_accept_reserve)
2750 if ((rc = verify_check_host(&smtp_reserve_hosts)) != OK)
2752 log_write(L_connection_reject,
2753 LOG_MAIN, "temporarily refused connection from %s: not in "
2754 "reserve list: connected=%d max=%d reserve=%d%s",
2755 host_and_ident(FALSE), smtp_accept_count - 1, smtp_accept_max,
2756 smtp_accept_reserve, (rc == DEFER)? " (lookup deferred)" : "");
2757 smtp_printf("421 %s: Too many concurrent SMTP connections; "
2758 "please try again later\r\n", FALSE, smtp_active_hostname);
2761 reserved_host = TRUE;
2764 /* If a load level above which only messages from reserved hosts are
2765 accepted is set, check the load. For incoming calls via the daemon, the
2766 check is done in the superior process if there are no reserved hosts, to
2767 save a fork. In all cases, the load average will already be available
2768 in a global variable at this point. */
2770 if (smtp_load_reserve >= 0 &&
2771 load_average > smtp_load_reserve &&
2773 verify_check_host(&smtp_reserve_hosts) != OK)
2775 log_write(L_connection_reject,
2776 LOG_MAIN, "temporarily refused connection from %s: not in "
2777 "reserve list and load average = %.2f", host_and_ident(FALSE),
2778 (double)load_average/1000.0);
2779 smtp_printf("421 %s: Too much load; please try again later\r\n", FALSE,
2780 smtp_active_hostname);
2784 /* Determine whether unqualified senders or recipients are permitted
2785 for this host. Unfortunately, we have to do this every time, in order to
2786 set the flags so that they can be inspected when considering qualifying
2787 addresses in the headers. For a site that permits no qualification, this
2788 won't take long, however. */
2790 allow_unqualified_sender =
2791 verify_check_host(&sender_unqualified_hosts) == OK;
2793 allow_unqualified_recipient =
2794 verify_check_host(&recipient_unqualified_hosts) == OK;
2796 /* Determine whether HELO/EHLO is required for this host. The requirement
2797 can be hard or soft. */
2799 helo_required = verify_check_host(&helo_verify_hosts) == OK;
2801 helo_verify = verify_check_host(&helo_try_verify_hosts) == OK;
2803 /* Determine whether this hosts is permitted to send syntactic junk
2804 after a HELO or EHLO command. */
2806 helo_accept_junk = verify_check_host(&helo_accept_junk_hosts) == OK;
2809 /* For batch SMTP input we are now done. */
2811 if (smtp_batched_input) return TRUE;
2813 /* If valid Proxy Protocol source is connecting, set up session.
2814 * Failure will not allow any SMTP function other than QUIT. */
2816 #ifdef SUPPORT_PROXY
2817 proxy_session = FALSE;
2818 proxy_session_failed = FALSE;
2819 if (check_proxy_protocol_host())
2820 setup_proxy_protocol_host();
2823 /* Start up TLS if tls_on_connect is set. This is for supporting the legacy
2824 smtps port for use with older style SSL MTAs. */
2827 if (tls_in.on_connect)
2829 if (tls_server_start(tls_require_ciphers, &user_msg) != OK)
2830 return smtp_log_tls_fail(user_msg);
2831 cmd_list[CMD_LIST_TLS_AUTH].is_mail_cmd = TRUE;
2835 /* Run the connect ACL if it exists */
2838 if (acl_smtp_connect)
2841 if ((rc = acl_check(ACL_WHERE_CONNECT, NULL, acl_smtp_connect, &user_msg,
2844 (void) smtp_handle_acl_fail(ACL_WHERE_CONNECT, rc, user_msg, log_msg);
2849 /* Output the initial message for a two-way SMTP connection. It may contain
2850 newlines, which then cause a multi-line response to be given. */
2852 code = US"220"; /* Default status code */
2853 esc = US""; /* Default extended status code */
2854 esclen = 0; /* Length of esc */
2858 if (!(s = expand_string(smtp_banner)))
2859 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "Expansion of \"%s\" (smtp_banner) "
2860 "failed: %s", smtp_banner, expand_string_message);
2866 smtp_message_code(&code, &codelen, &s, NULL, TRUE);
2870 esclen = codelen - 4;
2874 /* Remove any terminating newlines; might as well remove trailing space too */
2877 while (p > s && isspace(p[-1])) p--;
2880 /* It seems that CC:Mail is braindead, and assumes that the greeting message
2881 is all contained in a single IP packet. The original code wrote out the
2882 greeting using several calls to fprint/fputc, and on busy servers this could
2883 cause it to be split over more than one packet - which caused CC:Mail to fall
2884 over when it got the second part of the greeting after sending its first
2885 command. Sigh. To try to avoid this, build the complete greeting message
2886 first, and output it in one fell swoop. This gives a better chance of it
2887 ending up as a single packet. */
2889 ss = string_get(256);
2892 do /* At least once, in case we have an empty string */
2895 uschar *linebreak = Ustrchr(p, '\n');
2896 ss = string_catn(ss, code, 3);
2900 ss = string_catn(ss, US" ", 1);
2904 len = linebreak - p;
2905 ss = string_catn(ss, US"-", 1);
2907 ss = string_catn(ss, esc, esclen);
2908 ss = string_catn(ss, p, len);
2909 ss = string_catn(ss, US"\r\n", 2);
2915 /* Before we write the banner, check that there is no input pending, unless
2916 this synchronisation check is disabled. */
2920 unsigned n = smtp_inend - smtp_inptr;
2923 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP protocol "
2924 "synchronization error (input sent without waiting for greeting): "
2925 "rejected connection from %s input=\"%s\"", host_and_ident(TRUE),
2926 string_printing(string_copyn(smtp_inptr, n)));
2927 smtp_printf("554 SMTP synchronization error\r\n", FALSE);
2931 /* Now output the banner */
2933 smtp_printf("%s", FALSE, string_from_gstring(ss));
2935 /* Attempt to see if we sent the banner before the last ACK of the 3-way
2936 handshake arrived. If so we must have managed a TFO. */
2949 /*************************************************
2950 * Handle SMTP syntax and protocol errors *
2951 *************************************************/
2953 /* Write to the log for SMTP syntax errors in incoming commands, if configured
2954 to do so. Then transmit the error response. The return value depends on the
2955 number of syntax and protocol errors in this SMTP session.
2958 type error type, given as a log flag bit
2959 code response code; <= 0 means don't send a response
2960 data data to reflect in the response (can be NULL)
2961 errmess the error message
2963 Returns: -1 limit of syntax/protocol errors NOT exceeded
2964 +1 limit of syntax/protocol errors IS exceeded
2966 These values fit in with the values of the "done" variable in the main
2967 processing loop in smtp_setup_msg(). */
2970 synprot_error(int type, int code, uschar *data, uschar *errmess)
2974 log_write(type, LOG_MAIN, "SMTP %s error in \"%s\" %s %s",
2975 (type == L_smtp_syntax_error)? "syntax" : "protocol",
2976 string_printing(smtp_cmd_buffer), host_and_ident(TRUE), errmess);
2978 if (++synprot_error_count > smtp_max_synprot_errors)
2981 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
2982 "syntax or protocol errors (last command was \"%s\")",
2983 host_and_ident(FALSE), string_printing(smtp_cmd_buffer));
2988 smtp_printf("%d%c%s%s%s\r\n", FALSE, code, yield == 1 ? '-' : ' ',
2989 data ? data : US"", data ? US": " : US"", errmess);
2991 smtp_printf("%d Too many syntax or protocol errors\r\n", FALSE, code);
3000 /*************************************************
3001 * Send SMTP response, possibly multiline *
3002 *************************************************/
3004 /* There are, it seems, broken clients out there that cannot handle multiline
3005 responses. If no_multiline_responses is TRUE (it can be set from an ACL), we
3006 output nothing for non-final calls, and only the first line for anything else.
3009 code SMTP code, may involve extended status codes
3010 codelen length of smtp code; if > 4 there's an ESC
3011 final FALSE if the last line isn't the final line
3012 msg message text, possibly containing newlines
3018 smtp_respond(uschar* code, int codelen, BOOL final, uschar *msg)
3023 if (!final && no_multiline_responses) return;
3028 esclen = codelen - 4;
3031 /* If this is the first output for a (non-batch) RCPT command, see if all RCPTs
3032 have had the same. Note: this code is also present in smtp_printf(). It would
3033 be tidier to have it only in one place, but when it was added, it was easier to
3034 do it that way, so as not to have to mess with the code for the RCPT command,
3035 which sometimes uses smtp_printf() and sometimes smtp_respond(). */
3037 if (rcpt_in_progress)
3039 if (rcpt_smtp_response == NULL)
3040 rcpt_smtp_response = string_copy(msg);
3041 else if (rcpt_smtp_response_same &&
3042 Ustrcmp(rcpt_smtp_response, msg) != 0)
3043 rcpt_smtp_response_same = FALSE;
3044 rcpt_in_progress = FALSE;
3047 /* Now output the message, splitting it up into multiple lines if necessary.
3048 We only handle pipelining these responses as far as nonfinal/final groups,
3049 not the whole MAIL/RCPT/DATA response set. */
3053 uschar *nl = Ustrchr(msg, '\n');
3056 smtp_printf("%.3s%c%.*s%s\r\n", !final, code, final ? ' ':'-', esclen, esc, msg);
3059 else if (nl[1] == 0 || no_multiline_responses)
3061 smtp_printf("%.3s%c%.*s%.*s\r\n", !final, code, final ? ' ':'-', esclen, esc,
3062 (int)(nl - msg), msg);
3067 smtp_printf("%.3s-%.*s%.*s\r\n", TRUE, code, esclen, esc, (int)(nl - msg), msg);
3069 while (isspace(*msg)) msg++;
3077 /*************************************************
3078 * Parse user SMTP message *
3079 *************************************************/
3081 /* This function allows for user messages overriding the response code details
3082 by providing a suitable response code string at the start of the message
3083 user_msg. Check the message for starting with a response code and optionally an
3084 extended status code. If found, check that the first digit is valid, and if so,
3085 change the code pointer and length to use the replacement. An invalid code
3086 causes a panic log; in this case, if the log messages is the same as the user
3087 message, we must also adjust the value of the log message to show the code that
3088 is actually going to be used (the original one).
3090 This function is global because it is called from receive.c as well as within
3093 Note that the code length returned includes the terminating whitespace
3094 character, which is always included in the regex match.
3097 code SMTP code, may involve extended status codes
3098 codelen length of smtp code; if > 4 there's an ESC
3100 log_msg optional log message, to be adjusted with the new SMTP code
3101 check_valid if true, verify the response code
3107 smtp_message_code(uschar **code, int *codelen, uschar **msg, uschar **log_msg,
3113 if (!msg || !*msg) return;
3115 if ((n = pcre_exec(regex_smtp_code, NULL, CS *msg, Ustrlen(*msg), 0,
3116 PCRE_EOPT, ovector, sizeof(ovector)/sizeof(int))) < 0) return;
3118 if (check_valid && (*msg)[0] != (*code)[0])
3120 log_write(0, LOG_MAIN|LOG_PANIC, "configured error code starts with "
3121 "incorrect digit (expected %c) in \"%s\"", (*code)[0], *msg);
3122 if (log_msg != NULL && *log_msg == *msg)
3123 *log_msg = string_sprintf("%s %s", *code, *log_msg + ovector[1]);
3128 *codelen = ovector[1]; /* Includes final space */
3130 *msg += ovector[1]; /* Chop the code off the message */
3137 /*************************************************
3138 * Handle an ACL failure *
3139 *************************************************/
3141 /* This function is called when acl_check() fails. As well as calls from within
3142 this module, it is called from receive.c for an ACL after DATA. It sorts out
3143 logging the incident, and sends the error response. A message containing
3144 newlines is turned into a multiline SMTP response, but for logging, only the
3147 There's a table of default permanent failure response codes to use in
3148 globals.c, along with the table of names. VFRY is special. Despite RFC1123 it
3149 defaults disabled in Exim. However, discussion in connection with RFC 821bis
3150 (aka RFC 2821) has concluded that the response should be 252 in the disabled
3151 state, because there are broken clients that try VRFY before RCPT. A 5xx
3152 response should be given only when the address is positively known to be
3153 undeliverable. Sigh. We return 252 if there is no VRFY ACL or it provides
3154 no explicit code, but if there is one we let it know best.
3155 Also, for ETRN, 458 is given on refusal, and for AUTH, 503.
3157 From Exim 4.63, it is possible to override the response code details by
3158 providing a suitable response code string at the start of the message provided
3159 in user_msg. The code's first digit is checked for validity.
3162 where where the ACL was called from
3164 user_msg a message that can be included in an SMTP response
3165 log_msg a message for logging
3167 Returns: 0 in most cases
3168 2 if the failure code was FAIL_DROP, in which case the
3169 SMTP connection should be dropped (this value fits with the
3170 "done" variable in smtp_setup_msg() below)
3174 smtp_handle_acl_fail(int where, int rc, uschar *user_msg, uschar *log_msg)
3176 BOOL drop = rc == FAIL_DROP;
3180 uschar *sender_info = US"";
3182 #ifdef WITH_CONTENT_SCAN
3183 where == ACL_WHERE_MIME ? US"during MIME ACL checks" :
3185 where == ACL_WHERE_PREDATA ? US"DATA" :
3186 where == ACL_WHERE_DATA ? US"after DATA" :
3187 #ifndef DISABLE_PRDR
3188 where == ACL_WHERE_PRDR ? US"after DATA PRDR" :
3191 string_sprintf("%s %s", acl_wherenames[where], smtp_cmd_data) :
3192 string_sprintf("%s in \"connect\" ACL", acl_wherenames[where]);
3194 if (drop) rc = FAIL;
3196 /* Set the default SMTP code, and allow a user message to change it. */
3198 smtp_code = rc == FAIL ? acl_wherecodes[where] : US"451";
3199 smtp_message_code(&smtp_code, &codelen, &user_msg, &log_msg,
3200 where != ACL_WHERE_VRFY);
3202 /* We used to have sender_address here; however, there was a bug that was not
3203 updating sender_address after a rewrite during a verify. When this bug was
3204 fixed, sender_address at this point became the rewritten address. I'm not sure
3205 this is what should be logged, so I've changed to logging the unrewritten
3206 address to retain backward compatibility. */
3208 #ifndef WITH_CONTENT_SCAN
3209 if (where == ACL_WHERE_RCPT || where == ACL_WHERE_DATA)
3211 if (where == ACL_WHERE_RCPT || where == ACL_WHERE_DATA || where == ACL_WHERE_MIME)
3214 sender_info = string_sprintf("F=<%s>%s%s%s%s ",
3215 sender_address_unrewritten ? sender_address_unrewritten : sender_address,
3216 sender_host_authenticated ? US" A=" : US"",
3217 sender_host_authenticated ? sender_host_authenticated : US"",
3218 sender_host_authenticated && authenticated_id ? US":" : US"",
3219 sender_host_authenticated && authenticated_id ? authenticated_id : US""
3223 /* If there's been a sender verification failure with a specific message, and
3224 we have not sent a response about it yet, do so now, as a preliminary line for
3225 failures, but not defers. However, always log it for defer, and log it for fail
3226 unless the sender_verify_fail log selector has been turned off. */
3228 if (sender_verified_failed &&
3229 !testflag(sender_verified_failed, af_sverify_told))
3231 BOOL save_rcpt_in_progress = rcpt_in_progress;
3232 rcpt_in_progress = FALSE; /* So as not to treat these as the error */
3234 setflag(sender_verified_failed, af_sverify_told);
3236 if (rc != FAIL || LOGGING(sender_verify_fail))
3237 log_write(0, LOG_MAIN|LOG_REJECT, "%s sender verify %s for <%s>%s",
3238 host_and_ident(TRUE),
3239 ((sender_verified_failed->special_action & 255) == DEFER)? "defer":"fail",
3240 sender_verified_failed->address,
3241 (sender_verified_failed->message == NULL)? US"" :
3242 string_sprintf(": %s", sender_verified_failed->message));
3244 if (rc == FAIL && sender_verified_failed->user_message)
3245 smtp_respond(smtp_code, codelen, FALSE, string_sprintf(
3246 testflag(sender_verified_failed, af_verify_pmfail)?
3247 "Postmaster verification failed while checking <%s>\n%s\n"
3248 "Several RFCs state that you are required to have a postmaster\n"
3249 "mailbox for each mail domain. This host does not accept mail\n"
3250 "from domains whose servers reject the postmaster address."
3252 testflag(sender_verified_failed, af_verify_nsfail)?
3253 "Callback setup failed while verifying <%s>\n%s\n"
3254 "The initial connection, or a HELO or MAIL FROM:<> command was\n"
3255 "rejected. Refusing MAIL FROM:<> does not help fight spam, disregards\n"
3256 "RFC requirements, and stops you from receiving standard bounce\n"
3257 "messages. This host does not accept mail from domains whose servers\n"
3260 "Verification failed for <%s>\n%s",
3261 sender_verified_failed->address,
3262 sender_verified_failed->user_message));
3264 rcpt_in_progress = save_rcpt_in_progress;
3267 /* Sort out text for logging */
3269 log_msg = log_msg ? string_sprintf(": %s", log_msg) : US"";
3270 if ((lognl = Ustrchr(log_msg, '\n'))) *lognl = 0;
3272 /* Send permanent failure response to the command, but the code used isn't
3273 always a 5xx one - see comments at the start of this function. If the original
3274 rc was FAIL_DROP we drop the connection and yield 2. */
3277 smtp_respond(smtp_code, codelen, TRUE,
3278 user_msg ? user_msg : US"Administrative prohibition");
3280 /* Send temporary failure response to the command. Don't give any details,
3281 unless acl_temp_details is set. This is TRUE for a callout defer, a "defer"
3282 verb, and for a header verify when smtp_return_error_details is set.
3284 This conditional logic is all somewhat of a mess because of the odd
3285 interactions between temp_details and return_error_details. One day it should
3286 be re-implemented in a tidier fashion. */
3289 if (acl_temp_details && user_msg)
3291 if ( smtp_return_error_details
3292 && sender_verified_failed
3293 && sender_verified_failed->message
3295 smtp_respond(smtp_code, codelen, FALSE, sender_verified_failed->message);
3297 smtp_respond(smtp_code, codelen, TRUE, user_msg);
3300 smtp_respond(smtp_code, codelen, TRUE,
3301 US"Temporary local problem - please try later");
3303 /* Log the incident to the logs that are specified by log_reject_target
3304 (default main, reject). This can be empty to suppress logging of rejections. If
3305 the connection is not forcibly to be dropped, return 0. Otherwise, log why it
3306 is closing if required and return 2. */
3308 if (log_reject_target != 0)
3311 gstring * g = s_tlslog(NULL);
3312 uschar * tls = string_from_gstring(g);
3313 if (!tls) tls = US"";
3315 uschar * tls = US"";
3317 log_write(where == ACL_WHERE_CONNECT ? L_connection_reject : 0,
3318 log_reject_target, "%s%s%s %s%srejected %s%s",
3319 LOGGING(dnssec) && sender_host_dnssec ? US" DS" : US"",
3320 host_and_ident(TRUE),
3323 rc == FAIL ? US"" : US"temporarily ",
3327 if (!drop) return 0;
3329 log_write(L_smtp_connection, LOG_MAIN, "%s closed by DROP in ACL",
3330 smtp_get_connection_info());
3332 /* Run the not-quit ACL, but without any custom messages. This should not be a
3333 problem, because we get here only if some other ACL has issued "drop", and
3334 in that case, *its* custom messages will have been used above. */
3336 smtp_notquit_exit(US"acl-drop", NULL, NULL);
3343 /*************************************************
3344 * Handle SMTP exit when QUIT is not given *
3345 *************************************************/
3347 /* This function provides a logging/statistics hook for when an SMTP connection
3348 is dropped on the floor or the other end goes away. It's a global function
3349 because it's called from receive.c as well as this module. As well as running
3350 the NOTQUIT ACL, if there is one, this function also outputs a final SMTP
3351 response, either with a custom message from the ACL, or using a default. There
3352 is one case, however, when no message is output - after "drop". In that case,
3353 the ACL that obeyed "drop" has already supplied the custom message, and NULL is
3354 passed to this function.
3356 In case things go wrong while processing this function, causing an error that
3357 may re-enter this function, there is a recursion check.
3360 reason What $smtp_notquit_reason will be set to in the ACL;
3361 if NULL, the ACL is not run
3362 code The error code to return as part of the response
3363 defaultrespond The default message if there's no user_msg
3369 smtp_notquit_exit(uschar *reason, uschar *code, uschar *defaultrespond, ...)
3372 uschar *user_msg = NULL;
3373 uschar *log_msg = NULL;
3375 /* Check for recursive acll */
3377 if (smtp_exit_function_called)
3379 log_write(0, LOG_PANIC, "smtp_notquit_exit() called more than once (%s)",
3383 smtp_exit_function_called = TRUE;
3385 /* Call the not-QUIT ACL, if there is one, unless no reason is given. */
3387 if (acl_smtp_notquit && reason)
3389 smtp_notquit_reason = reason;
3390 if ((rc = acl_check(ACL_WHERE_NOTQUIT, NULL, acl_smtp_notquit, &user_msg,
3391 &log_msg)) == ERROR)
3392 log_write(0, LOG_MAIN|LOG_PANIC, "ACL for not-QUIT returned ERROR: %s",
3396 /* Write an SMTP response if we are expected to give one. As the default
3397 responses are all internal, they should always fit in the buffer, but code a
3398 warning, just in case. Note that string_vformat() still leaves a complete
3399 string, even if it is incomplete. */
3401 if (code && defaultrespond)
3404 smtp_respond(code, 3, TRUE, user_msg);
3409 va_start(ap, defaultrespond);
3410 if (!string_vformat(buffer, sizeof(buffer), CS defaultrespond, ap))
3411 log_write(0, LOG_MAIN|LOG_PANIC, "string too large in smtp_notquit_exit()");
3412 smtp_printf("%s %s\r\n", FALSE, code, buffer);
3422 /*************************************************
3423 * Verify HELO argument *
3424 *************************************************/
3426 /* This function is called if helo_verify_hosts or helo_try_verify_hosts is
3427 matched. It is also called from ACL processing if verify = helo is used and
3428 verification was not previously tried (i.e. helo_try_verify_hosts was not
3429 matched). The result of its processing is to set helo_verified and
3430 helo_verify_failed. These variables should both be FALSE for this function to
3433 Note that EHLO/HELO is legitimately allowed to quote an address literal. Allow
3434 for IPv6 ::ffff: literals.
3437 Returns: TRUE if testing was completed;
3438 FALSE on a temporary failure
3442 smtp_verify_helo(void)
3446 HDEBUG(D_receive) debug_printf("verifying EHLO/HELO argument \"%s\"\n",
3449 if (sender_helo_name == NULL)
3451 HDEBUG(D_receive) debug_printf("no EHLO/HELO command was issued\n");
3454 /* Deal with the case of -bs without an IP address */
3456 else if (sender_host_address == NULL)
3458 HDEBUG(D_receive) debug_printf("no client IP address: assume success\n");
3459 helo_verified = TRUE;
3462 /* Deal with the more common case when there is a sending IP address */
3464 else if (sender_helo_name[0] == '[')
3466 helo_verified = Ustrncmp(sender_helo_name+1, sender_host_address,
3467 Ustrlen(sender_host_address)) == 0;
3472 if (strncmpic(sender_host_address, US"::ffff:", 7) == 0)
3473 helo_verified = Ustrncmp(sender_helo_name + 1,
3474 sender_host_address + 7, Ustrlen(sender_host_address) - 7) == 0;
3479 { if (helo_verified) debug_printf("matched host address\n"); }
3482 /* Do a reverse lookup if one hasn't already given a positive or negative
3483 response. If that fails, or the name doesn't match, try checking with a forward
3488 if (sender_host_name == NULL && !host_lookup_failed)
3489 yield = host_name_lookup() != DEFER;
3491 /* If a host name is known, check it and all its aliases. */
3493 if (sender_host_name)
3494 if ((helo_verified = strcmpic(sender_host_name, sender_helo_name) == 0))
3496 sender_helo_dnssec = sender_host_dnssec;
3497 HDEBUG(D_receive) debug_printf("matched host name\n");
3501 uschar **aliases = sender_host_aliases;
3503 if ((helo_verified = strcmpic(*aliases++, sender_helo_name) == 0))
3505 sender_helo_dnssec = sender_host_dnssec;
3509 HDEBUG(D_receive) if (helo_verified)
3510 debug_printf("matched alias %s\n", *(--aliases));
3513 /* Final attempt: try a forward lookup of the helo name */
3522 h.name = sender_helo_name;
3529 HDEBUG(D_receive) debug_printf("getting IP address for %s\n",
3531 rc = host_find_bydns(&h, NULL, HOST_FIND_BY_A | HOST_FIND_BY_AAAA,
3532 NULL, NULL, NULL, &d, NULL, NULL);
3533 if (rc == HOST_FOUND || rc == HOST_FOUND_LOCAL)
3534 for (hh = &h; hh; hh = hh->next)
3535 if (Ustrcmp(hh->address, sender_host_address) == 0)
3537 helo_verified = TRUE;
3538 if (h.dnssec == DS_YES) sender_helo_dnssec = TRUE;
3541 debug_printf("IP address for %s matches calling address\n"
3542 "Forward DNS security status: %sverified\n",
3543 sender_helo_name, sender_helo_dnssec ? "" : "un");
3550 if (!helo_verified) helo_verify_failed = TRUE; /* We've tried ... */
3557 /*************************************************
3558 * Send user response message *
3559 *************************************************/
3561 /* This function is passed a default response code and a user message. It calls
3562 smtp_message_code() to check and possibly modify the response code, and then
3563 calls smtp_respond() to transmit the response. I put this into a function
3564 just to avoid a lot of repetition.
3567 code the response code
3568 user_msg the user message
3574 smtp_user_msg(uschar *code, uschar *user_msg)
3577 smtp_message_code(&code, &len, &user_msg, NULL, TRUE);
3578 smtp_respond(code, len, TRUE, user_msg);
3584 smtp_in_auth(auth_instance *au, uschar ** s, uschar ** ss)
3586 const uschar *set_id = NULL;
3589 /* Run the checking code, passing the remainder of the command line as
3590 data. Initials the $auth<n> variables as empty. Initialize $0 empty and set
3591 it as the only set numerical variable. The authenticator may set $auth<n>
3592 and also set other numeric variables. The $auth<n> variables are preferred
3593 nowadays; the numerical variables remain for backwards compatibility.
3595 Afterwards, have a go at expanding the set_id string, even if
3596 authentication failed - for bad passwords it can be useful to log the
3597 userid. On success, require set_id to expand and exist, and put it in
3598 authenticated_id. Save this in permanent store, as the working store gets
3599 reset at HELO, RSET, etc. */
3601 for (i = 0; i < AUTH_VARS; i++) auth_vars[i] = NULL;
3603 expand_nlength[0] = 0; /* $0 contains nothing */
3605 rc = (au->info->servercode)(au, smtp_cmd_data);
3606 if (au->set_id) set_id = expand_string(au->set_id);
3607 expand_nmax = -1; /* Reset numeric variables */
3608 for (i = 0; i < AUTH_VARS; i++) auth_vars[i] = NULL; /* Reset $auth<n> */
3610 /* The value of authenticated_id is stored in the spool file and printed in
3611 log lines. It must not contain binary zeros or newline characters. In
3612 normal use, it never will, but when playing around or testing, this error
3613 can (did) happen. To guard against this, ensure that the id contains only
3614 printing characters. */
3616 if (set_id) set_id = string_printing(set_id);
3618 /* For the non-OK cases, set up additional logging data if set_id
3622 set_id = set_id && *set_id
3623 ? string_sprintf(" (set_id=%s)", set_id) : US"";
3625 /* Switch on the result */
3630 if (!au->set_id || set_id) /* Complete success */
3632 if (set_id) authenticated_id = string_copy_malloc(set_id);
3633 sender_host_authenticated = au->name;
3634 sender_host_auth_pubname = au->public_name;
3635 authentication_failed = FALSE;
3636 authenticated_fail_id = NULL; /* Impossible to already be set? */
3639 (sender_host_address ? protocols : protocols_local)
3640 [pextend + pauthed + (tls_in.active >= 0 ? pcrpted:0)];
3641 *s = *ss = US"235 Authentication succeeded";
3642 authenticated_by = au;
3646 /* Authentication succeeded, but we failed to expand the set_id string.
3647 Treat this as a temporary error. */
3649 auth_defer_msg = expand_string_message;
3653 if (set_id) authenticated_fail_id = string_copy_malloc(set_id);
3654 *s = string_sprintf("435 Unable to authenticate at present%s",
3655 auth_defer_user_msg);
3656 *ss = string_sprintf("435 Unable to authenticate at present%s: %s",
3657 set_id, auth_defer_msg);
3661 *s = *ss = US"501 Invalid base64 data";
3665 *s = *ss = US"501 Authentication cancelled";
3669 *s = *ss = US"553 Initial data not expected";
3673 if (set_id) authenticated_fail_id = string_copy_malloc(set_id);
3674 *s = US"535 Incorrect authentication data";
3675 *ss = string_sprintf("535 Incorrect authentication data%s", set_id);
3679 if (set_id) authenticated_fail_id = string_copy_malloc(set_id);
3680 *s = US"435 Internal error";
3681 *ss = string_sprintf("435 Internal error%s: return %d from authentication "
3682 "check", set_id, rc);
3694 qualify_recipient(uschar ** recipient, uschar * smtp_cmd_data, uschar * tag)
3697 if (allow_unqualified_recipient || strcmpic(*recipient, US"postmaster") == 0)
3699 DEBUG(D_receive) debug_printf("unqualified address %s accepted\n",
3701 rd = Ustrlen(recipient) + 1;
3702 *recipient = rewrite_address_qualify(*recipient, TRUE);
3705 smtp_printf("501 %s: recipient address must contain a domain\r\n", FALSE,
3707 log_write(L_smtp_syntax_error,
3708 LOG_MAIN|LOG_REJECT, "unqualified %s rejected: <%s> %s%s",
3709 tag, *recipient, host_and_ident(TRUE), host_lookup_msg);
3717 smtp_quit_handler(uschar ** user_msgp, uschar ** log_msgp)
3720 incomplete_transaction_log(US"QUIT");
3723 int rc = acl_check(ACL_WHERE_QUIT, NULL, acl_smtp_quit, user_msgp, log_msgp);
3725 log_write(0, LOG_MAIN|LOG_PANIC, "ACL for QUIT returned ERROR: %s",
3729 smtp_respond(US"221", 3, TRUE, *user_msgp);
3731 smtp_printf("221 %s closing connection\r\n", FALSE, smtp_active_hostname);
3734 tls_close(TRUE, TLS_SHUTDOWN_NOWAIT);
3737 log_write(L_smtp_connection, LOG_MAIN, "%s closed by QUIT",
3738 smtp_get_connection_info());
3743 smtp_rset_handler(void)
3746 incomplete_transaction_log(US"RSET");
3747 smtp_printf("250 Reset OK\r\n", FALSE);
3748 cmd_list[CMD_LIST_RSET].is_mail_cmd = FALSE;
3753 /*************************************************
3754 * Initialize for SMTP incoming message *
3755 *************************************************/
3757 /* This function conducts the initial dialogue at the start of an incoming SMTP
3758 message, and builds a list of recipients. However, if the incoming message
3759 is part of a batch (-bS option) a separate function is called since it would
3760 be messy having tests splattered about all over this function. This function
3761 therefore handles the case where interaction is occurring. The input and output
3762 files are set up in smtp_in and smtp_out.
3764 The global recipients_list is set to point to a vector of recipient_item
3765 blocks, whose number is given by recipients_count. This is extended by the
3766 receive_add_recipient() function. The global variable sender_address is set to
3767 the sender's address. The yield is +1 if a message has been successfully
3768 started, 0 if a QUIT command was encountered or the connection was refused from
3769 the particular host, or -1 if the connection was lost.
3773 Returns: > 0 message successfully started (reached DATA)
3774 = 0 QUIT read or end of file reached or call refused
3779 smtp_setup_msg(void)
3782 BOOL toomany = FALSE;
3783 BOOL discarded = FALSE;
3784 BOOL last_was_rej_mail = FALSE;
3785 BOOL last_was_rcpt = FALSE;
3786 void *reset_point = store_get(0);
3788 DEBUG(D_receive) debug_printf("smtp_setup_msg entered\n");
3790 /* Reset for start of new message. We allow one RSET not to be counted as a
3791 nonmail command, for those MTAs that insist on sending it between every
3792 message. Ditto for EHLO/HELO and for STARTTLS, to allow for going in and out of
3793 TLS between messages (an Exim client may do this if it has messages queued up
3794 for the host). Note: we do NOT reset AUTH at this point. */
3796 smtp_reset(reset_point);
3797 message_ended = END_NOTSTARTED;
3799 chunking_state = chunking_offered ? CHUNKING_OFFERED : CHUNKING_NOT_OFFERED;
3801 cmd_list[CMD_LIST_RSET].is_mail_cmd = TRUE;
3802 cmd_list[CMD_LIST_HELO].is_mail_cmd = TRUE;
3803 cmd_list[CMD_LIST_EHLO].is_mail_cmd = TRUE;
3805 cmd_list[CMD_LIST_STARTTLS].is_mail_cmd = TRUE;
3808 /* Set the local signal handler for SIGTERM - it tries to end off tidily */
3810 os_non_restarting_signal(SIGTERM, command_sigterm_handler);
3812 /* Batched SMTP is handled in a different function. */
3814 if (smtp_batched_input) return smtp_setup_batch_msg();
3816 /* Deal with SMTP commands. This loop is exited by setting done to a POSITIVE
3817 value. The values are 2 larger than the required yield of the function. */
3821 const uschar **argv;
3822 uschar *etrn_command;
3823 uschar *etrn_serialize_key;
3825 uschar *log_msg, *smtp_code;
3826 uschar *user_msg = NULL;
3827 uschar *recipient = NULL;
3828 uschar *hello = NULL;
3830 BOOL was_rej_mail = FALSE;
3831 BOOL was_rcpt = FALSE;
3832 void (*oldsignal)(int);
3834 int start, end, sender_domain, recipient_domain;
3838 uschar *orcpt = NULL;
3843 /* Check once per STARTTLS or SSL-on-connect for a TLS AUTH */
3844 if ( tls_in.active >= 0
3846 && tls_in.certificate_verified
3847 && cmd_list[CMD_LIST_TLS_AUTH].is_mail_cmd
3850 cmd_list[CMD_LIST_TLS_AUTH].is_mail_cmd = FALSE;
3852 for (au = auths; au; au = au->next)
3853 if (strcmpic(US"tls", au->driver_name) == 0)
3856 && (rc = acl_check(ACL_WHERE_AUTH, NULL, acl_smtp_auth,
3857 &user_msg, &log_msg)) != OK
3859 done = smtp_handle_acl_fail(ACL_WHERE_AUTH, rc, user_msg, log_msg);
3862 smtp_cmd_data = NULL;
3864 if (smtp_in_auth(au, &s, &ss) == OK)
3865 { DEBUG(D_auth) debug_printf("tls auth succeeded\n"); }
3867 { DEBUG(D_auth) debug_printf("tls auth not succeeded\n"); }
3875 if (smtp_in) /* Avoid pure-ACKs while in cmd pingpong phase */
3876 (void) setsockopt(fileno(smtp_in), IPPROTO_TCP, TCP_QUICKACK,
3877 US &off, sizeof(off));
3880 switch(smtp_read_command(TRUE, GETC_BUFFER_UNLIMITED))
3882 /* The AUTH command is not permitted to occur inside a transaction, and may
3883 occur successfully only once per connection. Actually, that isn't quite
3884 true. When TLS is started, all previous information about a connection must
3885 be discarded, so a new AUTH is permitted at that time.
3887 AUTH may only be used when it has been advertised. However, it seems that
3888 there are clients that send AUTH when it hasn't been advertised, some of
3889 them even doing this after HELO. And there are MTAs that accept this. Sigh.
3890 So there's a get-out that allows this to happen.
3892 AUTH is initially labelled as a "nonmail command" so that one occurrence
3893 doesn't get counted. We change the label here so that multiple failing
3894 AUTHS will eventually hit the nonmail threshold. */
3898 authentication_failed = TRUE;
3899 cmd_list[CMD_LIST_AUTH].is_mail_cmd = FALSE;
3901 if (!auth_advertised && !allow_auth_unadvertised)
3903 done = synprot_error(L_smtp_protocol_error, 503, NULL,
3904 US"AUTH command used when not advertised");
3907 if (sender_host_authenticated)
3909 done = synprot_error(L_smtp_protocol_error, 503, NULL,
3910 US"already authenticated");
3915 done = synprot_error(L_smtp_protocol_error, 503, NULL,
3916 US"not permitted in mail transaction");
3923 && (rc = acl_check(ACL_WHERE_AUTH, NULL, acl_smtp_auth,
3924 &user_msg, &log_msg)) != OK
3927 done = smtp_handle_acl_fail(ACL_WHERE_AUTH, rc, user_msg, log_msg);
3931 /* Find the name of the requested authentication mechanism. */
3934 while ((c = *smtp_cmd_data) != 0 && !isspace(c))
3936 if (!isalnum(c) && c != '-' && c != '_')
3938 done = synprot_error(L_smtp_syntax_error, 501, NULL,
3939 US"invalid character in authentication mechanism name");
3945 /* If not at the end of the line, we must be at white space. Terminate the
3946 name and move the pointer on to any data that may be present. */
3948 if (*smtp_cmd_data != 0)
3950 *smtp_cmd_data++ = 0;
3951 while (isspace(*smtp_cmd_data)) smtp_cmd_data++;
3954 /* Search for an authentication mechanism which is configured for use
3955 as a server and which has been advertised (unless, sigh, allow_auth_
3956 unadvertised is set). */
3958 for (au = auths; au; au = au->next)
3959 if (strcmpic(s, au->public_name) == 0 && au->server &&
3960 (au->advertised || allow_auth_unadvertised))
3965 c = smtp_in_auth(au, &s, &ss);
3967 smtp_printf("%s\r\n", FALSE, s);
3969 log_write(0, LOG_MAIN|LOG_REJECT, "%s authenticator failed for %s: %s",
3970 au->name, host_and_ident(FALSE), ss);
3973 done = synprot_error(L_smtp_protocol_error, 504, NULL,
3974 string_sprintf("%s authentication mechanism not supported", s));
3976 break; /* AUTH_CMD */
3978 /* The HELO/EHLO commands are permitted to appear in the middle of a
3979 session as well as at the beginning. They have the effect of a reset in
3980 addition to their other functions. Their absence at the start cannot be
3981 taken to be an error.
3985 If the EHLO command is not acceptable to the SMTP server, 501, 500,
3986 or 502 failure replies MUST be returned as appropriate. The SMTP
3987 server MUST stay in the same state after transmitting these replies
3988 that it was in before the EHLO was received.
3990 Therefore, we do not do the reset until after checking the command for
3991 acceptability. This change was made for Exim release 4.11. Previously
3992 it did the reset first. */
4005 HELO_EHLO: /* Common code for HELO and EHLO */
4006 cmd_list[CMD_LIST_HELO].is_mail_cmd = FALSE;
4007 cmd_list[CMD_LIST_EHLO].is_mail_cmd = FALSE;
4009 /* Reject the HELO if its argument was invalid or non-existent. A
4010 successful check causes the argument to be saved in malloc store. */
4012 if (!check_helo(smtp_cmd_data))
4014 smtp_printf("501 Syntactically invalid %s argument(s)\r\n", FALSE, hello);
4016 log_write(0, LOG_MAIN|LOG_REJECT, "rejected %s from %s: syntactically "
4017 "invalid argument(s): %s", hello, host_and_ident(FALSE),
4018 (*smtp_cmd_argument == 0)? US"(no argument given)" :
4019 string_printing(smtp_cmd_argument));
4021 if (++synprot_error_count > smtp_max_synprot_errors)
4023 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
4024 "syntax or protocol errors (last command was \"%s\")",
4025 host_and_ident(FALSE), string_printing(smtp_cmd_buffer));
4032 /* If sender_host_unknown is true, we have got here via the -bs interface,
4033 not called from inetd. Otherwise, we are running an IP connection and the
4034 host address will be set. If the helo name is the primary name of this
4035 host and we haven't done a reverse lookup, force one now. If helo_required
4036 is set, ensure that the HELO name matches the actual host. If helo_verify
4037 is set, do the same check, but softly. */
4039 if (!sender_host_unknown)
4041 BOOL old_helo_verified = helo_verified;
4042 uschar *p = smtp_cmd_data;
4044 while (*p != 0 && !isspace(*p)) { *p = tolower(*p); p++; }
4047 /* Force a reverse lookup if HELO quoted something in helo_lookup_domains
4048 because otherwise the log can be confusing. */
4050 if ( !sender_host_name
4051 && (deliver_domain = sender_helo_name, /* set $domain */
4052 match_isinlist(sender_helo_name, CUSS &helo_lookup_domains, 0,
4053 &domainlist_anchor, NULL, MCL_DOMAIN, TRUE, NULL)) == OK)
4054 (void)host_name_lookup();
4056 /* Rebuild the fullhost info to include the HELO name (and the real name
4057 if it was looked up.) */
4059 host_build_sender_fullhost(); /* Rebuild */
4060 set_process_info("handling%s incoming connection from %s",
4061 (tls_in.active >= 0)? " TLS" : "", host_and_ident(FALSE));
4063 /* Verify if configured. This doesn't give much security, but it does
4064 make some people happy to be able to do it. If helo_required is set,
4065 (host matches helo_verify_hosts) failure forces rejection. If helo_verify
4066 is set (host matches helo_try_verify_hosts), it does not. This is perhaps
4067 now obsolescent, since the verification can now be requested selectively
4070 helo_verified = helo_verify_failed = sender_helo_dnssec = FALSE;
4071 if (helo_required || helo_verify)
4073 BOOL tempfail = !smtp_verify_helo();
4078 smtp_printf("%d %s argument does not match calling host\r\n", FALSE,
4079 tempfail? 451 : 550, hello);
4080 log_write(0, LOG_MAIN|LOG_REJECT, "%srejected \"%s %s\" from %s",
4081 tempfail? "temporarily " : "",
4082 hello, sender_helo_name, host_and_ident(FALSE));
4083 helo_verified = old_helo_verified;
4084 break; /* End of HELO/EHLO processing */
4086 HDEBUG(D_all) debug_printf("%s verification failed but host is in "
4087 "helo_try_verify_hosts\n", hello);
4093 /* set up SPF context */
4094 spf_init(sender_helo_name, sender_host_address);
4097 /* Apply an ACL check if one is defined; afterwards, recheck
4098 synchronization in case the client started sending in a delay. */
4101 if ((rc = acl_check(ACL_WHERE_HELO, NULL, acl_smtp_helo,
4102 &user_msg, &log_msg)) != OK)
4104 done = smtp_handle_acl_fail(ACL_WHERE_HELO, rc, user_msg, log_msg);
4105 if (sender_helo_name)
4107 store_free(sender_helo_name);
4108 sender_helo_name = NULL;
4110 host_build_sender_fullhost(); /* Rebuild */
4113 else if (!check_sync()) goto SYNC_FAILURE;
4115 /* Generate an OK reply. The default string includes the ident if present,
4116 and also the IP address if present. Reflecting back the ident is intended
4117 as a deterrent to mail forgers. For maximum efficiency, and also because
4118 some broken systems expect each response to be in a single packet, arrange
4119 that the entire reply is sent in one write(). */
4121 auth_advertised = FALSE;
4122 pipelining_advertised = FALSE;
4124 tls_advertised = FALSE;
4126 dsn_advertised = FALSE;
4128 smtputf8_advertised = FALSE;
4131 smtp_code = US"250 "; /* Default response code plus space*/
4134 s = string_sprintf("%.3s %s Hello %s%s%s",
4136 smtp_active_hostname,
4137 sender_ident ? sender_ident : US"",
4138 sender_ident ? US" at " : US"",
4139 sender_host_name ? sender_host_name : sender_helo_name);
4140 g = string_cat(NULL, s);
4142 if (sender_host_address)
4144 g = string_catn(g, US" [", 2);
4145 g = string_cat (g, sender_host_address);
4146 g = string_catn(g, US"]", 1);
4150 /* A user-supplied EHLO greeting may not contain more than one line. Note
4151 that the code returned by smtp_message_code() includes the terminating
4152 whitespace character. */
4158 smtp_message_code(&smtp_code, &codelen, &user_msg, NULL, TRUE);
4159 s = string_sprintf("%.*s%s", codelen, smtp_code, user_msg);
4160 if ((ss = strpbrk(CS s, "\r\n")) != NULL)
4162 log_write(0, LOG_MAIN|LOG_PANIC, "EHLO/HELO response must not contain "
4163 "newlines: message truncated: %s", string_printing(s));
4166 g = string_cat(NULL, s);
4169 g = string_catn(g, US"\r\n", 2);
4171 /* If we received EHLO, we must create a multiline response which includes
4172 the functions supported. */
4178 /* I'm not entirely happy with this, as an MTA is supposed to check
4179 that it has enough room to accept a message of maximum size before
4180 it sends this. However, there seems little point in not sending it.
4181 The actual size check happens later at MAIL FROM time. By postponing it
4182 till then, VRFY and EXPN can be used after EHLO when space is short. */
4184 if (thismessage_size_limit > 0)
4186 sprintf(CS big_buffer, "%.3s-SIZE %d\r\n", smtp_code,
4187 thismessage_size_limit);
4188 g = string_cat(g, big_buffer);
4192 g = string_catn(g, smtp_code, 3);
4193 g = string_catn(g, US"-SIZE\r\n", 7);
4196 /* Exim does not do protocol conversion or data conversion. It is 8-bit
4197 clean; if it has an 8-bit character in its hand, it just sends it. It
4198 cannot therefore specify 8BITMIME and remain consistent with the RFCs.
4199 However, some users want this option simply in order to stop MUAs
4200 mangling messages that contain top-bit-set characters. It is therefore
4201 provided as an option. */
4203 if (accept_8bitmime)
4205 g = string_catn(g, smtp_code, 3);
4206 g = string_catn(g, US"-8BITMIME\r\n", 11);
4209 /* Advertise DSN support if configured to do so. */
4210 if (verify_check_host(&dsn_advertise_hosts) != FAIL)
4212 g = string_catn(g, smtp_code, 3);
4213 g = string_catn(g, US"-DSN\r\n", 6);
4214 dsn_advertised = TRUE;
4217 /* Advertise ETRN/VRFY/EXPN if there's are ACL checking whether a host is
4218 permitted to issue them; a check is made when any host actually tries. */
4222 g = string_catn(g, smtp_code, 3);
4223 g = string_catn(g, US"-ETRN\r\n", 7);
4227 g = string_catn(g, smtp_code, 3);
4228 g = string_catn(g, US"-VRFY\r\n", 7);
4232 g = string_catn(g, smtp_code, 3);
4233 g = string_catn(g, US"-EXPN\r\n", 7);
4236 /* Exim is quite happy with pipelining, so let the other end know that
4237 it is safe to use it, unless advertising is disabled. */
4239 if (pipelining_enable &&
4240 verify_check_host(&pipelining_advertise_hosts) == OK)
4242 g = string_catn(g, smtp_code, 3);
4243 g = string_catn(g, US"-PIPELINING\r\n", 13);
4244 sync_cmd_limit = NON_SYNC_CMD_PIPELINING;
4245 pipelining_advertised = TRUE;
4249 /* If any server authentication mechanisms are configured, advertise
4250 them if the current host is in auth_advertise_hosts. The problem with
4251 advertising always is that some clients then require users to
4252 authenticate (and aren't configurable otherwise) even though it may not
4253 be necessary (e.g. if the host is in host_accept_relay).
4255 RFC 2222 states that SASL mechanism names contain only upper case
4256 letters, so output the names in upper case, though we actually recognize
4257 them in either case in the AUTH command. */
4261 && !sender_host_authenticated
4263 && verify_check_host(&auth_advertise_hosts) == OK
4268 for (au = auths; au; au = au->next)
4270 au->advertised = FALSE;
4273 DEBUG(D_auth+D_expand) debug_printf_indent(
4274 "Evaluating advertise_condition for %s athenticator\n",
4276 if ( !au->advertise_condition
4277 || expand_check_condition(au->advertise_condition, au->name,
4284 g = string_catn(g, smtp_code, 3);
4285 g = string_catn(g, US"-AUTH", 5);
4287 auth_advertised = TRUE;
4290 g = string_catn(g, US" ", 1);
4291 g = string_cat (g, au->public_name);
4292 while (++saveptr < g->ptr) g->s[saveptr] = toupper(g->s[saveptr]);
4293 au->advertised = TRUE;
4298 if (!first) g = string_catn(g, US"\r\n", 2);
4301 /* RFC 3030 CHUNKING */
4303 if (verify_check_host(&chunking_advertise_hosts) != FAIL)
4305 g = string_catn(g, smtp_code, 3);
4306 g = string_catn(g, US"-CHUNKING\r\n", 11);
4307 chunking_offered = TRUE;
4308 chunking_state = CHUNKING_OFFERED;
4311 /* Advertise TLS (Transport Level Security) aka SSL (Secure Socket Layer)
4312 if it has been included in the binary, and the host matches
4313 tls_advertise_hosts. We must *not* advertise if we are already in a
4314 secure connection. */
4317 if (tls_in.active < 0 &&
4318 verify_check_host(&tls_advertise_hosts) != FAIL)
4320 g = string_catn(g, smtp_code, 3);
4321 g = string_catn(g, US"-STARTTLS\r\n", 11);
4322 tls_advertised = TRUE;
4326 #ifndef DISABLE_PRDR
4327 /* Per Recipient Data Response, draft by Eric A. Hall extending RFC */
4330 g = string_catn(g, smtp_code, 3);
4331 g = string_catn(g, US"-PRDR\r\n", 7);
4336 if ( accept_8bitmime
4337 && verify_check_host(&smtputf8_advertise_hosts) != FAIL)
4339 g = string_catn(g, smtp_code, 3);
4340 g = string_catn(g, US"-SMTPUTF8\r\n", 11);
4341 smtputf8_advertised = TRUE;
4345 /* Finish off the multiline reply with one that is always available. */
4347 g = string_catn(g, smtp_code, 3);
4348 g = string_catn(g, US" HELP\r\n", 7);
4351 /* Terminate the string (for debug), write it, and note that HELO/EHLO
4355 if (tls_in.active >= 0) (void)tls_write(TRUE, g->s, g->ptr, FALSE); else
4359 int i = fwrite(g->s, 1, g->ptr, smtp_out); i = i; /* compiler quietening */
4365 (void) string_from_gstring(g);
4366 while ((cr = Ustrchr(g->s, '\r')) != NULL) /* lose CRs */
4367 memmove(cr, cr + 1, (g->ptr--) - (cr - g->s));
4368 debug_printf("SMTP>> %s", g->s);
4372 /* Reset the protocol and the state, abandoning any previous message. */
4374 (sender_host_address ? protocols : protocols_local)
4376 ? pextend + (sender_host_authenticated ? pauthed : 0)
4378 + (tls_in.active >= 0 ? pcrpted : 0)
4380 cancel_cutthrough_connection(TRUE, US"sent EHLO response");
4381 smtp_reset(reset_point);
4383 break; /* HELO/EHLO */
4386 /* The MAIL command requires an address as an operand. All we do
4387 here is to parse it for syntactic correctness. The form "<>" is
4388 a special case which converts into an empty string. The start/end
4389 pointers in the original are not used further for this address, as
4390 it is the canonical extracted address which is all that is kept. */
4394 smtp_mailcmd_count++; /* Count for limit and ratelimit */
4395 was_rej_mail = TRUE; /* Reset if accepted */
4396 env_mail_type_t * mail_args; /* Sanity check & validate args */
4398 if (helo_required && !helo_seen)
4400 smtp_printf("503 HELO or EHLO required\r\n", FALSE);
4401 log_write(0, LOG_MAIN|LOG_REJECT, "rejected MAIL from %s: no "
4402 "HELO/EHLO given", host_and_ident(FALSE));
4406 if (sender_address != NULL)
4408 done = synprot_error(L_smtp_protocol_error, 503, NULL,
4409 US"sender already given");
4413 if (smtp_cmd_data[0] == 0)
4415 done = synprot_error(L_smtp_protocol_error, 501, NULL,
4416 US"MAIL must have an address operand");
4420 /* Check to see if the limit for messages per connection would be
4421 exceeded by accepting further messages. */
4423 if (smtp_accept_max_per_connection > 0 &&
4424 smtp_mailcmd_count > smtp_accept_max_per_connection)
4426 smtp_printf("421 too many messages in this connection\r\n", FALSE);
4427 log_write(0, LOG_MAIN|LOG_REJECT, "rejected MAIL command %s: too many "
4428 "messages in one connection", host_and_ident(TRUE));
4432 /* Reset for start of message - even if this is going to fail, we
4433 obviously need to throw away any previous data. */
4435 cancel_cutthrough_connection(TRUE, US"MAIL received");
4436 smtp_reset(reset_point);
4438 sender_data = recipient_data = NULL;
4440 /* Loop, checking for ESMTP additions to the MAIL FROM command. */
4444 uschar *name, *value, *end;
4445 unsigned long int size;
4446 BOOL arg_error = FALSE;
4448 if (!extract_option(&name, &value)) break;
4450 for (mail_args = env_mail_type_list;
4451 mail_args->value != ENV_MAIL_OPT_NULL;
4454 if (strcmpic(name, mail_args->name) == 0)
4456 if (mail_args->need_value && strcmpic(value, US"") == 0)
4459 switch(mail_args->value)
4461 /* Handle SIZE= by reading the value. We don't do the check till later,
4462 in order to be able to log the sender address on failure. */
4463 case ENV_MAIL_OPT_SIZE:
4464 if (((size = Ustrtoul(value, &end, 10)), *end == 0))
4466 if ((size == ULONG_MAX && errno == ERANGE) || size > INT_MAX)
4468 message_size = (int)size;
4474 /* If this session was initiated with EHLO and accept_8bitmime is set,
4475 Exim will have indicated that it supports the BODY=8BITMIME option. In
4476 fact, it does not support this according to the RFCs, in that it does not
4477 take any special action for forwarding messages containing 8-bit
4478 characters. That is why accept_8bitmime is not the default setting, but
4479 some sites want the action that is provided. We recognize both "8BITMIME"
4480 and "7BIT" as body types, but take no action. */
4481 case ENV_MAIL_OPT_BODY:
4482 if (accept_8bitmime) {
4483 if (strcmpic(value, US"8BITMIME") == 0)
4485 else if (strcmpic(value, US"7BIT") == 0)
4490 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4491 US"invalid data for BODY");
4494 DEBUG(D_receive) debug_printf("8BITMIME: %d\n", body_8bitmime);
4500 /* Handle the two DSN options, but only if configured to do so (which
4501 will have caused "DSN" to be given in the EHLO response). The code itself
4502 is included only if configured in at build time. */
4504 case ENV_MAIL_OPT_RET:
4507 /* Check if RET has already been set */
4510 synprot_error(L_smtp_syntax_error, 501, NULL,
4511 US"RET can be specified once only");
4514 dsn_ret = strcmpic(value, US"HDRS") == 0
4516 : strcmpic(value, US"FULL") == 0
4519 DEBUG(D_receive) debug_printf("DSN_RET: %d\n", dsn_ret);
4520 /* Check for invalid invalid value, and exit with error */
4523 synprot_error(L_smtp_syntax_error, 501, NULL,
4524 US"Value for RET is invalid");
4529 case ENV_MAIL_OPT_ENVID:
4532 /* Check if the dsn envid has been already set */
4533 if (dsn_envid != NULL)
4535 synprot_error(L_smtp_syntax_error, 501, NULL,
4536 US"ENVID can be specified once only");
4539 dsn_envid = string_copy(value);
4540 DEBUG(D_receive) debug_printf("DSN_ENVID: %s\n", dsn_envid);
4544 /* Handle the AUTH extension. If the value given is not "<>" and either
4545 the ACL says "yes" or there is no ACL but the sending host is
4546 authenticated, we set it up as the authenticated sender. However, if the
4547 authenticator set a condition to be tested, we ignore AUTH on MAIL unless
4548 the condition is met. The value of AUTH is an xtext, which means that +,
4549 = and cntrl chars are coded in hex; however "<>" is unaffected by this
4551 case ENV_MAIL_OPT_AUTH:
4552 if (Ustrcmp(value, "<>") != 0)
4557 if (auth_xtextdecode(value, &authenticated_sender) < 0)
4559 /* Put back terminator overrides for error message */
4562 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4563 US"invalid data for AUTH");
4566 if (!acl_smtp_mailauth)
4568 ignore_msg = US"client not authenticated";
4569 rc = sender_host_authenticated ? OK : FAIL;
4573 ignore_msg = US"rejected by ACL";
4574 rc = acl_check(ACL_WHERE_MAILAUTH, NULL, acl_smtp_mailauth,
4575 &user_msg, &log_msg);
4581 if (authenticated_by == NULL ||
4582 authenticated_by->mail_auth_condition == NULL ||
4583 expand_check_condition(authenticated_by->mail_auth_condition,
4584 authenticated_by->name, US"authenticator"))
4585 break; /* Accept the AUTH */
4587 ignore_msg = US"server_mail_auth_condition failed";
4588 if (authenticated_id != NULL)
4589 ignore_msg = string_sprintf("%s: authenticated ID=\"%s\"",
4590 ignore_msg, authenticated_id);
4595 authenticated_sender = NULL;
4596 log_write(0, LOG_MAIN, "ignoring AUTH=%s from %s (%s)",
4597 value, host_and_ident(TRUE), ignore_msg);
4600 /* Should only get DEFER or ERROR here. Put back terminator
4601 overrides for error message */
4606 (void)smtp_handle_acl_fail(ACL_WHERE_MAILAUTH, rc, user_msg,
4613 #ifndef DISABLE_PRDR
4614 case ENV_MAIL_OPT_PRDR:
4616 prdr_requested = TRUE;
4621 case ENV_MAIL_OPT_UTF8:
4622 if (smtputf8_advertised)
4624 int old_pool = store_pool;
4626 DEBUG(D_receive) debug_printf("smtputf8 requested\n");
4627 message_smtputf8 = allow_utf8_domains = TRUE;
4628 store_pool = POOL_PERM;
4629 received_protocol = string_sprintf("utf8%s", received_protocol);
4630 store_pool = old_pool;
4634 /* No valid option. Stick back the terminator characters and break
4635 the loop. Do the name-terminator second as extract_option sets
4636 value==name when it found no equal-sign.
4637 An error for a malformed address will occur. */
4638 case ENV_MAIL_OPT_NULL:
4646 /* Break out of for loop if switch() had bad argument or
4647 when start of the email address is reached */
4648 if (arg_error) break;
4651 /* If we have passed the threshold for rate limiting, apply the current
4652 delay, and update it for next time, provided this is a limited host. */
4654 if (smtp_mailcmd_count > smtp_rlm_threshold &&
4655 verify_check_host(&smtp_ratelimit_hosts) == OK)
4657 DEBUG(D_receive) debug_printf("rate limit MAIL: delay %.3g sec\n",
4658 smtp_delay_mail/1000.0);
4659 millisleep((int)smtp_delay_mail);
4660 smtp_delay_mail *= smtp_rlm_factor;
4661 if (smtp_delay_mail > (double)smtp_rlm_limit)
4662 smtp_delay_mail = (double)smtp_rlm_limit;
4665 /* Now extract the address, first applying any SMTP-time rewriting. The
4666 TRUE flag allows "<>" as a sender address. */
4668 raw_sender = rewrite_existflags & rewrite_smtp
4669 ? rewrite_one(smtp_cmd_data, rewrite_smtp, NULL, FALSE, US"",
4670 global_rewrite_rules)
4674 parse_extract_address(raw_sender, &errmess, &start, &end, &sender_domain,
4679 done = synprot_error(L_smtp_syntax_error, 501, smtp_cmd_data, errmess);
4683 sender_address = raw_sender;
4685 /* If there is a configured size limit for mail, check that this message
4686 doesn't exceed it. The check is postponed to this point so that the sender
4689 if (thismessage_size_limit > 0 && message_size > thismessage_size_limit)
4691 smtp_printf("552 Message size exceeds maximum permitted\r\n", FALSE);
4692 log_write(L_size_reject,
4693 LOG_MAIN|LOG_REJECT, "rejected MAIL FROM:<%s> %s: "
4694 "message too big: size%s=%d max=%d",
4696 host_and_ident(TRUE),
4697 (message_size == INT_MAX)? ">" : "",
4699 thismessage_size_limit);
4700 sender_address = NULL;
4704 /* Check there is enough space on the disk unless configured not to.
4705 When smtp_check_spool_space is set, the check is for thismessage_size_limit
4706 plus the current message - i.e. we accept the message only if it won't
4707 reduce the space below the threshold. Add 5000 to the size to allow for
4708 overheads such as the Received: line and storing of recipients, etc.
4709 By putting the check here, even when SIZE is not given, it allow VRFY
4710 and EXPN etc. to be used when space is short. */
4712 if (!receive_check_fs(
4713 (smtp_check_spool_space && message_size >= 0)?
4714 message_size + 5000 : 0))
4716 smtp_printf("452 Space shortage, please try later\r\n", FALSE);
4717 sender_address = NULL;
4721 /* If sender_address is unqualified, reject it, unless this is a locally
4722 generated message, or the sending host or net is permitted to send
4723 unqualified addresses - typically local machines behaving as MUAs -
4724 in which case just qualify the address. The flag is set above at the start
4725 of the SMTP connection. */
4727 if (sender_domain == 0 && sender_address[0] != 0)
4729 if (allow_unqualified_sender)
4731 sender_domain = Ustrlen(sender_address) + 1;
4732 sender_address = rewrite_address_qualify(sender_address, FALSE);
4733 DEBUG(D_receive) debug_printf("unqualified address %s accepted\n",
4738 smtp_printf("501 %s: sender address must contain a domain\r\n", FALSE,
4740 log_write(L_smtp_syntax_error,
4741 LOG_MAIN|LOG_REJECT,
4742 "unqualified sender rejected: <%s> %s%s",
4744 host_and_ident(TRUE),
4746 sender_address = NULL;
4751 /* Apply an ACL check if one is defined, before responding. Afterwards,
4752 when pipelining is not advertised, do another sync check in case the ACL
4753 delayed and the client started sending in the meantime. */
4757 rc = acl_check(ACL_WHERE_MAIL, NULL, acl_smtp_mail, &user_msg, &log_msg);
4758 if (rc == OK && !pipelining_advertised && !check_sync())
4764 if (rc == OK || rc == DISCARD)
4766 BOOL more = pipeline_response();
4769 smtp_printf("%s%s%s", more, US"250 OK",
4770 #ifndef DISABLE_PRDR
4771 prdr_requested ? US", PRDR Requested" : US"",
4778 #ifndef DISABLE_PRDR
4780 user_msg = string_sprintf("%s%s", user_msg, US", PRDR Requested");
4782 smtp_user_msg(US"250", user_msg);
4784 smtp_delay_rcpt = smtp_rlr_base;
4785 recipients_discarded = (rc == DISCARD);
4786 was_rej_mail = FALSE;
4790 done = smtp_handle_acl_fail(ACL_WHERE_MAIL, rc, user_msg, log_msg);
4791 sender_address = NULL;
4796 /* The RCPT command requires an address as an operand. There may be any
4797 number of RCPT commands, specifying multiple recipients. We build them all
4798 into a data structure. The start/end values given by parse_extract_address
4799 are not used, as we keep only the extracted address. */
4804 was_rcpt = rcpt_in_progress = TRUE;
4806 /* There must be a sender address; if the sender was rejected and
4807 pipelining was advertised, we assume the client was pipelining, and do not
4808 count this as a protocol error. Reset was_rej_mail so that further RCPTs
4809 get the same treatment. */
4811 if (sender_address == NULL)
4813 if (pipelining_advertised && last_was_rej_mail)
4815 smtp_printf("503 sender not yet given\r\n", FALSE);
4816 was_rej_mail = TRUE;
4820 done = synprot_error(L_smtp_protocol_error, 503, NULL,
4821 US"sender not yet given");
4822 was_rcpt = FALSE; /* Not a valid RCPT */
4828 /* Check for an operand */
4830 if (smtp_cmd_data[0] == 0)
4832 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4833 US"RCPT must have an address operand");
4838 /* Set the DSN flags orcpt and dsn_flags from the session*/
4844 uschar *name, *value;
4846 if (!extract_option(&name, &value))
4849 if (dsn_advertised && strcmpic(name, US"ORCPT") == 0)
4851 /* Check whether orcpt has been already set */
4854 synprot_error(L_smtp_syntax_error, 501, NULL,
4855 US"ORCPT can be specified once only");
4858 orcpt = string_copy(value);
4859 DEBUG(D_receive) debug_printf("DSN orcpt: %s\n", orcpt);
4862 else if (dsn_advertised && strcmpic(name, US"NOTIFY") == 0)
4864 /* Check if the notify flags have been already set */
4867 synprot_error(L_smtp_syntax_error, 501, NULL,
4868 US"NOTIFY can be specified once only");
4871 if (strcmpic(value, US"NEVER") == 0)
4872 flags |= rf_notify_never;
4879 while (*pp != 0 && *pp != ',') pp++;
4880 if (*pp == ',') *pp++ = 0;
4881 if (strcmpic(p, US"SUCCESS") == 0)
4883 DEBUG(D_receive) debug_printf("DSN: Setting notify success\n");
4884 flags |= rf_notify_success;
4886 else if (strcmpic(p, US"FAILURE") == 0)
4888 DEBUG(D_receive) debug_printf("DSN: Setting notify failure\n");
4889 flags |= rf_notify_failure;
4891 else if (strcmpic(p, US"DELAY") == 0)
4893 DEBUG(D_receive) debug_printf("DSN: Setting notify delay\n");
4894 flags |= rf_notify_delay;
4898 /* Catch any strange values */
4899 synprot_error(L_smtp_syntax_error, 501, NULL,
4900 US"Invalid value for NOTIFY parameter");
4905 DEBUG(D_receive) debug_printf("DSN Flags: %x\n", flags);
4909 /* Unknown option. Stick back the terminator characters and break
4910 the loop. An error for a malformed address will occur. */
4914 DEBUG(D_receive) debug_printf("Invalid RCPT option: %s : %s\n", name, value);
4921 /* Apply SMTP rewriting then extract the working address. Don't allow "<>"
4922 as a recipient address */
4924 recipient = rewrite_existflags & rewrite_smtp
4925 ? rewrite_one(smtp_cmd_data, rewrite_smtp, NULL, FALSE, US"",
4926 global_rewrite_rules)
4929 if (!(recipient = parse_extract_address(recipient, &errmess, &start, &end,
4930 &recipient_domain, FALSE)))
4932 done = synprot_error(L_smtp_syntax_error, 501, smtp_cmd_data, errmess);
4937 /* If the recipient address is unqualified, reject it, unless this is a
4938 locally generated message. However, unqualified addresses are permitted
4939 from a configured list of hosts and nets - typically when behaving as
4940 MUAs rather than MTAs. Sad that SMTP is used for both types of traffic,
4941 really. The flag is set at the start of the SMTP connection.
4943 RFC 1123 talks about supporting "the reserved mailbox postmaster"; I always
4944 assumed this meant "reserved local part", but the revision of RFC 821 and
4945 friends now makes it absolutely clear that it means *mailbox*. Consequently
4946 we must always qualify this address, regardless. */
4948 if (!recipient_domain)
4949 if (!(recipient_domain = qualify_recipient(&recipient, smtp_cmd_data,
4956 /* Check maximum allowed */
4958 if (rcpt_count > recipients_max && recipients_max > 0)
4960 if (recipients_max_reject)
4963 smtp_printf("552 too many recipients\r\n", FALSE);
4965 log_write(0, LOG_MAIN|LOG_REJECT, "too many recipients: message "
4966 "rejected: sender=<%s> %s", sender_address, host_and_ident(TRUE));
4971 smtp_printf("452 too many recipients\r\n", FALSE);
4973 log_write(0, LOG_MAIN|LOG_REJECT, "too many recipients: excess "
4974 "temporarily rejected: sender=<%s> %s", sender_address,
4975 host_and_ident(TRUE));
4982 /* If we have passed the threshold for rate limiting, apply the current
4983 delay, and update it for next time, provided this is a limited host. */
4985 if (rcpt_count > smtp_rlr_threshold &&
4986 verify_check_host(&smtp_ratelimit_hosts) == OK)
4988 DEBUG(D_receive) debug_printf("rate limit RCPT: delay %.3g sec\n",
4989 smtp_delay_rcpt/1000.0);
4990 millisleep((int)smtp_delay_rcpt);
4991 smtp_delay_rcpt *= smtp_rlr_factor;
4992 if (smtp_delay_rcpt > (double)smtp_rlr_limit)
4993 smtp_delay_rcpt = (double)smtp_rlr_limit;
4996 /* If the MAIL ACL discarded all the recipients, we bypass ACL checking
4997 for them. Otherwise, check the access control list for this recipient. As
4998 there may be a delay in this, re-check for a synchronization error
4999 afterwards, unless pipelining was advertised. */
5001 if (recipients_discarded)
5004 if ( (rc = acl_check(ACL_WHERE_RCPT, recipient, acl_smtp_rcpt, &user_msg,
5006 && !pipelining_advertised && !check_sync())
5009 /* The ACL was happy */
5013 BOOL more = pipeline_response();
5016 smtp_user_msg(US"250", user_msg);
5018 smtp_printf("250 Accepted\r\n", more);
5019 receive_add_recipient(recipient, -1);
5021 /* Set the dsn flags in the recipients_list */
5022 recipients_list[recipients_count-1].orcpt = orcpt;
5023 recipients_list[recipients_count-1].dsn_flags = flags;
5025 DEBUG(D_receive) debug_printf("DSN: orcpt: %s flags: %d\n",
5026 recipients_list[recipients_count-1].orcpt,
5027 recipients_list[recipients_count-1].dsn_flags);
5030 /* The recipient was discarded */
5032 else if (rc == DISCARD)
5035 smtp_user_msg(US"250", user_msg);
5037 smtp_printf("250 Accepted\r\n", FALSE);
5040 log_write(0, LOG_MAIN|LOG_REJECT, "%s F=<%s> RCPT %s: "
5041 "discarded by %s ACL%s%s", host_and_ident(TRUE),
5042 sender_address_unrewritten? sender_address_unrewritten : sender_address,
5043 smtp_cmd_argument, recipients_discarded? "MAIL" : "RCPT",
5044 log_msg ? US": " : US"", log_msg ? log_msg : US"");
5047 /* Either the ACL failed the address, or it was deferred. */
5051 if (rc == FAIL) rcpt_fail_count++; else rcpt_defer_count++;
5052 done = smtp_handle_acl_fail(ACL_WHERE_RCPT, rc, user_msg, log_msg);
5057 /* The DATA command is legal only if it follows successful MAIL FROM
5058 and RCPT TO commands. However, if pipelining is advertised, a bad DATA is
5059 not counted as a protocol error if it follows RCPT (which must have been
5060 rejected if there are no recipients.) This function is complete when a
5061 valid DATA command is encountered.
5063 Note concerning the code used: RFC 2821 says this:
5065 - If there was no MAIL, or no RCPT, command, or all such commands
5066 were rejected, the server MAY return a "command out of sequence"
5067 (503) or "no valid recipients" (554) reply in response to the
5070 The example in the pipelining RFC 2920 uses 554, but I use 503 here
5071 because it is the same whether pipelining is in use or not.
5073 If all the RCPT commands that precede DATA provoked the same error message
5074 (often indicating some kind of system error), it is helpful to include it
5075 with the DATA rejection (an idea suggested by Tony Finch). */
5082 if (chunking_state != CHUNKING_OFFERED)
5084 done = synprot_error(L_smtp_protocol_error, 503, NULL,
5085 US"BDAT command used when CHUNKING not advertised");
5089 /* grab size, endmarker */
5091 if (sscanf(CS smtp_cmd_data, "%u %n", &chunking_datasize, &n) < 1)
5093 done = synprot_error(L_smtp_protocol_error, 501, NULL,
5094 US"missing size for BDAT command");
5097 chunking_state = strcmpic(smtp_cmd_data+n, US"LAST") == 0
5098 ? CHUNKING_LAST : CHUNKING_ACTIVE;
5099 chunking_data_left = chunking_datasize;
5100 DEBUG(D_receive) debug_printf("chunking state %d, %d bytes\n",
5101 (int)chunking_state, chunking_data_left);
5103 /* push the current receive_* function on the "stack", and
5104 replace them by bdat_getc(), which in turn will use the lwr_receive_*
5105 functions to do the dirty work. */
5106 lwr_receive_getc = receive_getc;
5107 lwr_receive_getbuf = receive_getbuf;
5108 lwr_receive_ungetc = receive_ungetc;
5110 receive_getc = bdat_getc;
5111 receive_ungetc = bdat_ungetc;
5122 DATA_BDAT: /* Common code for DATA and BDAT */
5123 if (!discarded && recipients_count <= 0)
5125 if (rcpt_smtp_response_same && rcpt_smtp_response != NULL)
5127 uschar *code = US"503";
5128 int len = Ustrlen(rcpt_smtp_response);
5129 smtp_respond(code, 3, FALSE, US"All RCPT commands were rejected with "
5131 /* Responses from smtp_printf() will have \r\n on the end */
5132 if (len > 2 && rcpt_smtp_response[len-2] == '\r')
5133 rcpt_smtp_response[len-2] = 0;
5134 smtp_respond(code, 3, FALSE, rcpt_smtp_response);
5136 if (pipelining_advertised && last_was_rcpt)
5137 smtp_printf("503 Valid RCPT command must precede %s\r\n", FALSE,
5138 smtp_names[smtp_connection_had[smtp_ch_index-1]]);
5140 done = synprot_error(L_smtp_protocol_error, 503, NULL,
5141 smtp_connection_had[smtp_ch_index-1] == SCH_DATA
5142 ? US"valid RCPT command must precede DATA"
5143 : US"valid RCPT command must precede BDAT");
5145 if (chunking_state > CHUNKING_OFFERED)
5150 if (toomany && recipients_max_reject)
5152 sender_address = NULL; /* This will allow a new MAIL without RSET */
5153 sender_address_unrewritten = NULL;
5154 smtp_printf("554 Too many recipients\r\n", FALSE);
5158 if (chunking_state > CHUNKING_OFFERED)
5159 rc = OK; /* No predata ACL or go-ahead output for BDAT */
5162 /* If there is an ACL, re-check the synchronization afterwards, since the
5163 ACL may have delayed. To handle cutthrough delivery enforce a dummy call
5164 to get the DATA command sent. */
5166 if (acl_smtp_predata == NULL && cutthrough.fd < 0)
5170 uschar * acl = acl_smtp_predata ? acl_smtp_predata : US"accept";
5171 enable_dollar_recipients = TRUE;
5172 rc = acl_check(ACL_WHERE_PREDATA, NULL, acl, &user_msg,
5174 enable_dollar_recipients = FALSE;
5175 if (rc == OK && !check_sync())
5179 { /* Either the ACL failed the address, or it was deferred. */
5180 done = smtp_handle_acl_fail(ACL_WHERE_PREDATA, rc, user_msg, log_msg);
5186 smtp_user_msg(US"354", user_msg);
5189 "354 Enter message, ending with \".\" on a line by itself\r\n", FALSE);
5193 if (smtp_in) /* all ACKs needed to ramp window up for bulk data */
5194 (void) setsockopt(fileno(smtp_in), IPPROTO_TCP, TCP_QUICKACK,
5195 US &on, sizeof(on));
5198 message_ended = END_NOTENDED; /* Indicate in middle of data */
5209 if (!(address = parse_extract_address(smtp_cmd_data, &errmess,
5210 &start, &end, &recipient_domain, FALSE)))
5212 smtp_printf("501 %s\r\n", FALSE, errmess);
5216 if (!recipient_domain)
5217 if (!(recipient_domain = qualify_recipient(&address, smtp_cmd_data,
5221 if ((rc = acl_check(ACL_WHERE_VRFY, address, acl_smtp_vrfy,
5222 &user_msg, &log_msg)) != OK)
5223 done = smtp_handle_acl_fail(ACL_WHERE_VRFY, rc, user_msg, log_msg);
5227 address_item * addr = deliver_make_addr(address, FALSE);
5229 switch(verify_address(addr, NULL, vopt_is_recipient | vopt_qualify, -1,
5230 -1, -1, NULL, NULL, NULL))
5233 s = string_sprintf("250 <%s> is deliverable", address);
5237 s = (addr->user_message != NULL)?
5238 string_sprintf("451 <%s> %s", address, addr->user_message) :
5239 string_sprintf("451 Cannot resolve <%s> at this time", address);
5243 s = (addr->user_message != NULL)?
5244 string_sprintf("550 <%s> %s", address, addr->user_message) :
5245 string_sprintf("550 <%s> is not deliverable", address);
5246 log_write(0, LOG_MAIN, "VRFY failed for %s %s",
5247 smtp_cmd_argument, host_and_ident(TRUE));
5251 smtp_printf("%s\r\n", FALSE, s);
5259 rc = acl_check(ACL_WHERE_EXPN, NULL, acl_smtp_expn, &user_msg, &log_msg);
5261 done = smtp_handle_acl_fail(ACL_WHERE_EXPN, rc, user_msg, log_msg);
5264 BOOL save_log_testing_mode = log_testing_mode;
5265 address_test_mode = log_testing_mode = TRUE;
5266 (void) verify_address(deliver_make_addr(smtp_cmd_data, FALSE),
5267 smtp_out, vopt_is_recipient | vopt_qualify | vopt_expn, -1, -1, -1,
5269 address_test_mode = FALSE;
5270 log_testing_mode = save_log_testing_mode; /* true for -bh */
5279 if (!tls_advertised)
5281 done = synprot_error(L_smtp_protocol_error, 503, NULL,
5282 US"STARTTLS command used when not advertised");
5286 /* Apply an ACL check if one is defined */
5288 if ( acl_smtp_starttls
5289 && (rc = acl_check(ACL_WHERE_STARTTLS, NULL, acl_smtp_starttls,
5290 &user_msg, &log_msg)) != OK
5293 done = smtp_handle_acl_fail(ACL_WHERE_STARTTLS, rc, user_msg, log_msg);
5297 /* RFC 2487 is not clear on when this command may be sent, though it
5298 does state that all information previously obtained from the client
5299 must be discarded if a TLS session is started. It seems reasonable to
5300 do an implied RSET when STARTTLS is received. */
5302 incomplete_transaction_log(US"STARTTLS");
5303 cancel_cutthrough_connection(TRUE, US"STARTTLS received");
5304 smtp_reset(reset_point);
5306 cmd_list[CMD_LIST_STARTTLS].is_mail_cmd = FALSE;
5308 /* There's an attack where more data is read in past the STARTTLS command
5309 before TLS is negotiated, then assumed to be part of the secure session
5310 when used afterwards; we use segregated input buffers, so are not
5311 vulnerable, but we want to note when it happens and, for sheer paranoia,
5312 ensure that the buffer is "wiped".
5313 Pipelining sync checks will normally have protected us too, unless disabled
5314 by configuration. */
5316 if (receive_smtp_buffered())
5319 debug_printf("Non-empty input buffer after STARTTLS; naive attack?\n");
5320 if (tls_in.active < 0)
5321 smtp_inend = smtp_inptr = smtp_inbuffer;
5322 /* and if TLS is already active, tls_server_start() should fail */
5325 /* There is nothing we value in the input buffer and if TLS is successfully
5326 negotiated, we won't use this buffer again; if TLS fails, we'll just read
5327 fresh content into it. The buffer contains arbitrary content from an
5328 untrusted remote source; eg: NOOP <shellcode>\r\nSTARTTLS\r\n
5329 It seems safest to just wipe away the content rather than leave it as a
5330 target to jump to. */
5332 memset(smtp_inbuffer, 0, IN_BUFFER_SIZE);
5334 /* Attempt to start up a TLS session, and if successful, discard all
5335 knowledge that was obtained previously. At least, that's what the RFC says,
5336 and that's what happens by default. However, in order to work round YAEB,
5337 there is an option to remember the esmtp state. Sigh.
5339 We must allow for an extra EHLO command and an extra AUTH command after
5340 STARTTLS that don't add to the nonmail command count. */
5343 if ((rc = tls_server_start(tls_require_ciphers, &s)) == OK)
5345 if (!tls_remember_esmtp)
5346 helo_seen = esmtp = auth_advertised = pipelining_advertised = FALSE;
5347 cmd_list[CMD_LIST_EHLO].is_mail_cmd = TRUE;
5348 cmd_list[CMD_LIST_AUTH].is_mail_cmd = TRUE;
5349 cmd_list[CMD_LIST_TLS_AUTH].is_mail_cmd = TRUE;
5350 if (sender_helo_name)
5352 store_free(sender_helo_name);
5353 sender_helo_name = NULL;
5354 host_build_sender_fullhost(); /* Rebuild */
5355 set_process_info("handling incoming TLS connection from %s",
5356 host_and_ident(FALSE));
5359 (sender_host_address ? protocols : protocols_local)
5361 ? pextend + (sender_host_authenticated ? pauthed : 0)
5363 + (tls_in.active >= 0 ? pcrpted : 0)
5366 sender_host_auth_pubname = sender_host_authenticated = NULL;
5367 authenticated_id = NULL;
5368 sync_cmd_limit = NON_SYNC_CMD_NON_PIPELINING;
5369 DEBUG(D_tls) debug_printf("TLS active\n");
5370 break; /* Successful STARTTLS */
5373 (void) smtp_log_tls_fail(s);
5375 /* Some local configuration problem was discovered before actually trying
5376 to do a TLS handshake; give a temporary error. */
5380 smtp_printf("454 TLS currently unavailable\r\n", FALSE);
5384 /* Hard failure. Reject everything except QUIT or closed connection. One
5385 cause for failure is a nested STARTTLS, in which case tls_in.active remains
5386 set, but we must still reject all incoming commands. */
5388 DEBUG(D_tls) debug_printf("TLS failed to start\n");
5389 while (done <= 0) switch(smtp_read_command(FALSE, GETC_BUFFER_UNLIMITED))
5392 log_write(L_smtp_connection, LOG_MAIN, "%s closed by EOF",
5393 smtp_get_connection_info());
5394 smtp_notquit_exit(US"tls-failed", NULL, NULL);
5398 /* It is perhaps arguable as to which exit ACL should be called here,
5399 but as it is probably a situation that almost never arises, it
5400 probably doesn't matter. We choose to call the real QUIT ACL, which in
5401 some sense is perhaps "right". */
5406 && ((rc = acl_check(ACL_WHERE_QUIT, NULL, acl_smtp_quit, &user_msg,
5407 &log_msg)) == ERROR))
5408 log_write(0, LOG_MAIN|LOG_PANIC, "ACL for QUIT returned ERROR: %s",
5411 smtp_respond(US"221", 3, TRUE, user_msg);
5413 smtp_printf("221 %s closing connection\r\n", FALSE, smtp_active_hostname);
5414 log_write(L_smtp_connection, LOG_MAIN, "%s closed by QUIT",
5415 smtp_get_connection_info());
5420 smtp_printf("554 Security failure\r\n", FALSE);
5423 tls_close(TRUE, TLS_SHUTDOWN_NOWAIT);
5428 /* The ACL for QUIT is provided for gathering statistical information or
5429 similar; it does not affect the response code, but it can supply a custom
5433 smtp_quit_handler(&user_msg, &log_msg);
5439 smtp_rset_handler();
5440 cancel_cutthrough_connection(TRUE, US"RSET received");
5441 smtp_reset(reset_point);
5448 smtp_printf("250 OK\r\n", FALSE);
5452 /* Show ETRN/EXPN/VRFY if there's an ACL for checking hosts; if actually
5453 used, a check will be done for permitted hosts. Show STARTTLS only if not
5454 already in a TLS session and if it would be advertised in the EHLO
5459 smtp_printf("214-Commands supported:\r\n", TRUE);
5463 Ustrcat(buffer, " AUTH");
5465 if (tls_in.active < 0 &&
5466 verify_check_host(&tls_advertise_hosts) != FAIL)
5467 Ustrcat(buffer, " STARTTLS");
5469 Ustrcat(buffer, " HELO EHLO MAIL RCPT DATA BDAT");
5470 Ustrcat(buffer, " NOOP QUIT RSET HELP");
5471 if (acl_smtp_etrn != NULL) Ustrcat(buffer, " ETRN");
5472 if (acl_smtp_expn != NULL) Ustrcat(buffer, " EXPN");
5473 if (acl_smtp_vrfy != NULL) Ustrcat(buffer, " VRFY");
5474 smtp_printf("214%s\r\n", FALSE, buffer);
5480 incomplete_transaction_log(US"connection lost");
5481 smtp_notquit_exit(US"connection-lost", US"421",
5482 US"%s lost input connection", smtp_active_hostname);
5484 /* Don't log by default unless in the middle of a message, as some mailers
5485 just drop the call rather than sending QUIT, and it clutters up the logs.
5488 if (sender_address || recipients_count > 0)
5489 log_write(L_lost_incoming_connection, LOG_MAIN,
5490 "unexpected %s while reading SMTP command from %s%s%s D=%s",
5491 sender_host_unknown ? "EOF" : "disconnection",
5492 tcp_in_fastopen && !tcp_in_fastopen_logged ? US"TFO " : US"",
5493 host_and_ident(FALSE), smtp_read_error,
5494 string_timesince(&smtp_connection_start)
5498 log_write(L_smtp_connection, LOG_MAIN, "%s %slost%s D=%s",
5499 smtp_get_connection_info(),
5500 tcp_in_fastopen && !tcp_in_fastopen_logged ? US"TFO " : US"",
5502 string_timesince(&smtp_connection_start)
5513 done = synprot_error(L_smtp_protocol_error, 503, NULL,
5514 US"ETRN is not permitted inside a transaction");
5518 log_write(L_etrn, LOG_MAIN, "ETRN %s received from %s", smtp_cmd_argument,
5519 host_and_ident(FALSE));
5521 if ((rc = acl_check(ACL_WHERE_ETRN, NULL, acl_smtp_etrn,
5522 &user_msg, &log_msg)) != OK)
5524 done = smtp_handle_acl_fail(ACL_WHERE_ETRN, rc, user_msg, log_msg);
5528 /* Compute the serialization key for this command. */
5530 etrn_serialize_key = string_sprintf("etrn-%s\n", smtp_cmd_data);
5532 /* If a command has been specified for running as a result of ETRN, we
5533 permit any argument to ETRN. If not, only the # standard form is permitted,
5534 since that is strictly the only kind of ETRN that can be implemented
5535 according to the RFC. */
5537 if (smtp_etrn_command)
5541 etrn_command = smtp_etrn_command;
5542 deliver_domain = smtp_cmd_data;
5543 rc = transport_set_up_command(&argv, smtp_etrn_command, TRUE, 0, NULL,
5544 US"ETRN processing", &error);
5545 deliver_domain = NULL;
5548 log_write(0, LOG_MAIN|LOG_PANIC, "failed to set up ETRN command: %s",
5550 smtp_printf("458 Internal failure\r\n", FALSE);
5555 /* Else set up to call Exim with the -R option. */
5559 if (*smtp_cmd_data++ != '#')
5561 done = synprot_error(L_smtp_syntax_error, 501, NULL,
5562 US"argument must begin with #");
5565 etrn_command = US"exim -R";
5566 argv = CUSS child_exec_exim(CEE_RETURN_ARGV, TRUE, NULL, TRUE,
5567 *queue_name ? 4 : 2,
5568 US"-R", smtp_cmd_data,
5569 US"-MCG", queue_name);
5572 /* If we are host-testing, don't actually do anything. */
5578 debug_printf("ETRN command is: %s\n", etrn_command);
5579 debug_printf("ETRN command execution skipped\n");
5581 if (user_msg == NULL) smtp_printf("250 OK\r\n", FALSE);
5582 else smtp_user_msg(US"250", user_msg);
5587 /* If ETRN queue runs are to be serialized, check the database to
5588 ensure one isn't already running. */
5590 if (smtp_etrn_serialize && !enq_start(etrn_serialize_key, 1))
5592 smtp_printf("458 Already processing %s\r\n", FALSE, smtp_cmd_data);
5596 /* Fork a child process and run the command. We don't want to have to
5597 wait for the process at any point, so set SIGCHLD to SIG_IGN before
5598 forking. It should be set that way anyway for external incoming SMTP,
5599 but we save and restore to be tidy. If serialization is required, we
5600 actually run the command in yet another process, so we can wait for it
5601 to complete and then remove the serialization lock. */
5603 oldsignal = signal(SIGCHLD, SIG_IGN);
5605 if ((pid = fork()) == 0)
5607 smtp_input = FALSE; /* This process is not associated with the */
5608 (void)fclose(smtp_in); /* SMTP call any more. */
5609 (void)fclose(smtp_out);
5611 signal(SIGCHLD, SIG_DFL); /* Want to catch child */
5613 /* If not serializing, do the exec right away. Otherwise, fork down
5614 into another process. */
5616 if (!smtp_etrn_serialize || (pid = fork()) == 0)
5618 DEBUG(D_exec) debug_print_argv(argv);
5619 exim_nullstd(); /* Ensure std{in,out,err} exist */
5620 execv(CS argv[0], (char *const *)argv);
5621 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "exec of \"%s\" (ETRN) failed: %s",
5622 etrn_command, strerror(errno));
5623 _exit(EXIT_FAILURE); /* paranoia */
5626 /* Obey this if smtp_serialize and the 2nd fork yielded non-zero. That
5627 is, we are in the first subprocess, after forking again. All we can do
5628 for a failing fork is to log it. Otherwise, wait for the 2nd process to
5629 complete, before removing the serialization. */
5632 log_write(0, LOG_MAIN|LOG_PANIC, "2nd fork for serialized ETRN "
5633 "failed: %s", strerror(errno));
5637 DEBUG(D_any) debug_printf("waiting for serialized ETRN process %d\n",
5639 (void)wait(&status);
5640 DEBUG(D_any) debug_printf("serialized ETRN process %d ended\n",
5644 enq_end(etrn_serialize_key);
5645 _exit(EXIT_SUCCESS);
5648 /* Back in the top level SMTP process. Check that we started a subprocess
5649 and restore the signal state. */
5653 log_write(0, LOG_MAIN|LOG_PANIC, "fork of process for ETRN failed: %s",
5655 smtp_printf("458 Unable to fork process\r\n", FALSE);
5656 if (smtp_etrn_serialize) enq_end(etrn_serialize_key);
5660 if (user_msg == NULL) smtp_printf("250 OK\r\n", FALSE);
5661 else smtp_user_msg(US"250", user_msg);
5664 signal(SIGCHLD, oldsignal);
5669 done = synprot_error(L_smtp_syntax_error, 501, NULL,
5670 US"unexpected argument data");
5674 /* This currently happens only for NULLs, but could be extended. */
5677 done = synprot_error(L_smtp_syntax_error, 0, NULL, /* Just logs */
5678 US"NUL character(s) present (shown as '?')");
5679 smtp_printf("501 NUL characters are not allowed in SMTP commands\r\n", FALSE);
5685 if (smtp_inend >= smtp_inbuffer + IN_BUFFER_SIZE)
5686 smtp_inend = smtp_inbuffer + IN_BUFFER_SIZE - 1;
5687 c = smtp_inend - smtp_inptr;
5688 if (c > 150) c = 150; /* limit logged amount */
5690 incomplete_transaction_log(US"sync failure");
5691 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP protocol synchronization error "
5692 "(next input sent too soon: pipelining was%s advertised): "
5693 "rejected \"%s\" %s next input=\"%s\"",
5694 pipelining_advertised? "" : " not",
5695 smtp_cmd_buffer, host_and_ident(TRUE),
5696 string_printing(smtp_inptr));
5697 smtp_notquit_exit(US"synchronization-error", US"554",
5698 US"SMTP synchronization error");
5699 done = 1; /* Pretend eof - drops connection */
5703 case TOO_MANY_NONMAIL_CMD:
5704 s = smtp_cmd_buffer;
5705 while (*s != 0 && !isspace(*s)) s++;
5706 incomplete_transaction_log(US"too many non-mail commands");
5707 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
5708 "nonmail commands (last was \"%.*s\")", host_and_ident(FALSE),
5709 (int)(s - smtp_cmd_buffer), smtp_cmd_buffer);
5710 smtp_notquit_exit(US"bad-commands", US"554", US"Too many nonmail commands");
5711 done = 1; /* Pretend eof - drops connection */
5714 #ifdef SUPPORT_PROXY
5715 case PROXY_FAIL_IGNORE_CMD:
5716 smtp_printf("503 Command refused, required Proxy negotiation failed\r\n", FALSE);
5721 if (unknown_command_count++ >= smtp_max_unknown_commands)
5723 log_write(L_smtp_syntax_error, LOG_MAIN,
5724 "SMTP syntax error in \"%s\" %s %s",
5725 string_printing(smtp_cmd_buffer), host_and_ident(TRUE),
5726 US"unrecognized command");
5727 incomplete_transaction_log(US"unrecognized command");
5728 smtp_notquit_exit(US"bad-commands", US"500",
5729 US"Too many unrecognized commands");
5731 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
5732 "unrecognized commands (last was \"%s\")", host_and_ident(FALSE),
5733 string_printing(smtp_cmd_buffer));
5736 done = synprot_error(L_smtp_syntax_error, 500, NULL,
5737 US"unrecognized command");
5741 /* This label is used by goto's inside loops that want to break out to
5742 the end of the command-processing loop. */
5745 last_was_rej_mail = was_rej_mail; /* Remember some last commands for */
5746 last_was_rcpt = was_rcpt; /* protocol error handling */
5750 return done - 2; /* Convert yield values */
5756 authres_smtpauth(gstring * g)
5758 if (!sender_host_authenticated)
5761 g = string_append(g, 2, US";\n\tauth=pass (", sender_host_auth_pubname);
5763 if (Ustrcmp(sender_host_auth_pubname, "tls") != 0)
5764 g = string_append(g, 2, US") smtp.auth=", authenticated_id);
5765 else if (authenticated_id)
5766 g = string_append(g, 2, US") x509.auth=", authenticated_id);
5768 g = string_catn(g, US") reason=x509.auth", 17);
5770 if (authenticated_sender)
5771 g = string_append(g, 2, US" smtp.mailfrom=", authenticated_sender);
5779 /* End of smtp_in.c */