1 /*************************************************
2 * Exim - an Internet mail transport agent *
3 *************************************************/
5 /* Copyright (c) University of Cambridge 1995 - 2018 */
6 /* Copyright (c) The Exim Maintainers 2020 */
7 /* See the file NOTICE for conditions of use and distribution. */
9 /* Functions for handling an incoming SMTP call. */
16 /* Initialize for TCP wrappers if so configured. It appears that the macro
17 HAVE_IPV6 is used in some versions of the tcpd.h header, so we unset it before
18 including that header, and restore its value afterwards. */
20 #ifdef USE_TCP_WRAPPERS
23 #define EXIM_HAVE_IPV6
29 #define HAVE_IPV6 TRUE
32 int allow_severity = LOG_INFO;
33 int deny_severity = LOG_NOTICE;
34 uschar *tcp_wrappers_name;
38 /* Size of buffer for reading SMTP commands. We used to use 512, as defined
39 by RFC 821. However, RFC 1869 specifies that this must be increased for SMTP
40 commands that accept arguments, and this in particular applies to AUTH, where
41 the data can be quite long. More recently this value was 2048 in Exim;
42 however, RFC 4954 (circa 2007) recommends 12288 bytes to handle AUTH. Clients
43 such as Thunderbird will send an AUTH with an initial-response for GSSAPI.
44 The maximum size of a Kerberos ticket under Windows 2003 is 12000 bytes, and
45 we need room to handle large base64-encoded AUTHs for GSSAPI.
48 #define SMTP_CMD_BUFFER_SIZE 16384
50 /* Size of buffer for reading SMTP incoming packets */
52 #define IN_BUFFER_SIZE 8192
54 /* Structure for SMTP command list */
61 short int is_mail_cmd;
64 /* Codes for identifying commands. We order them so that those that come first
65 are those for which synchronization is always required. Checking this can help
69 /* These commands are required to be synchronized, i.e. to be the last in a
70 block of commands when pipelining. */
72 HELO_CMD, EHLO_CMD, DATA_CMD, /* These are listed in the pipelining */
73 VRFY_CMD, EXPN_CMD, NOOP_CMD, /* RFC as requiring synchronization */
74 ETRN_CMD, /* This by analogy with TURN from the RFC */
75 STARTTLS_CMD, /* Required by the STARTTLS RFC */
76 TLS_AUTH_CMD, /* auto-command at start of SSL */
78 /* This is a dummy to identify the non-sync commands when pipelining */
80 NON_SYNC_CMD_PIPELINING,
82 /* These commands need not be synchronized when pipelining */
84 MAIL_CMD, RCPT_CMD, RSET_CMD,
86 /* This is a dummy to identify the non-sync commands when not pipelining */
88 NON_SYNC_CMD_NON_PIPELINING,
90 /* RFC3030 section 2: "After all MAIL and RCPT responses are collected and
91 processed the message is sent using a series of BDAT commands"
92 implies that BDAT should be synchronized. However, we see Google, at least,
93 sending MAIL,RCPT,BDAT-LAST in a single packet, clearly not waiting for
94 processing of the RCPT response(s). We shall do the same, and not require
95 synch for BDAT. Worse, as the chunk may (very likely will) follow the
96 command-header in the same packet we cannot do the usual "is there any
97 follow-on data after the command line" even for non-pipeline mode.
98 So we'll need an explicit check after reading the expected chunk amount
99 when non-pipe, before sending the ACK. */
103 /* I have been unable to find a statement about the use of pipelining
104 with AUTH, so to be on the safe side it is here, though I kind of feel
105 it should be up there with the synchronized commands. */
109 /* I'm not sure about these, but I don't think they matter. */
114 PROXY_FAIL_IGNORE_CMD,
117 /* These are specials that don't correspond to actual commands */
119 EOF_CMD, OTHER_CMD, BADARG_CMD, BADCHAR_CMD, BADSYN_CMD,
120 TOO_MANY_NONMAIL_CMD };
123 /* This is a convenience macro for adding the identity of an SMTP command
124 to the circular buffer that holds a list of the last n received. */
127 smtp_connection_had[smtp_ch_index++] = n; \
128 if (smtp_ch_index >= SMTP_HBUFF_SIZE) smtp_ch_index = 0
131 /*************************************************
132 * Local static variables *
133 *************************************************/
136 BOOL auth_advertised :1;
138 BOOL tls_advertised :1;
140 BOOL dsn_advertised :1;
142 BOOL helo_required :1;
145 BOOL helo_accept_junk :1;
146 #ifndef DISABLE_PIPE_CONNECT
147 BOOL pipe_connect_acceptable :1;
149 BOOL rcpt_smtp_response_same :1;
150 BOOL rcpt_in_progress :1;
151 BOOL smtp_exit_function_called :1;
153 BOOL smtputf8_advertised :1;
156 .helo_required = FALSE,
157 .helo_verify = FALSE,
158 .smtp_exit_function_called = FALSE,
161 static auth_instance *authenticated_by;
162 static int count_nonmail;
163 static int nonmail_command_count;
164 static int synprot_error_count;
165 static int unknown_command_count;
166 static int sync_cmd_limit;
167 static int smtp_write_error = 0;
169 static uschar *rcpt_smtp_response;
170 static uschar *smtp_data_buffer;
171 static uschar *smtp_cmd_data;
173 /* We need to know the position of RSET, HELO, EHLO, AUTH, and STARTTLS. Their
174 final fields of all except AUTH are forced TRUE at the start of a new message
175 setup, to allow one of each between messages that is not counted as a nonmail
176 command. (In fact, only one of HELO/EHLO is not counted.) Also, we have to
177 allow a new EHLO after starting up TLS.
179 AUTH is "falsely" labelled as a mail command initially, so that it doesn't get
180 counted. However, the flag is changed when AUTH is received, so that multiple
181 failing AUTHs will eventually hit the limit. After a successful AUTH, another
182 AUTH is already forbidden. After a TLS session is started, AUTH's flag is again
183 forced TRUE, to allow for the re-authentication that can happen at that point.
185 QUIT is also "falsely" labelled as a mail command so that it doesn't up the
186 count of non-mail commands and possibly provoke an error.
188 tls_auth is a pseudo-command, never expected in input. It is activated
189 on TLS startup and looks for a tls authenticator. */
191 static smtp_cmd_list cmd_list[] = {
192 /* name len cmd has_arg is_mail_cmd */
194 { "rset", sizeof("rset")-1, RSET_CMD, FALSE, FALSE }, /* First */
195 { "helo", sizeof("helo")-1, HELO_CMD, TRUE, FALSE },
196 { "ehlo", sizeof("ehlo")-1, EHLO_CMD, TRUE, FALSE },
197 { "auth", sizeof("auth")-1, AUTH_CMD, TRUE, TRUE },
199 { "starttls", sizeof("starttls")-1, STARTTLS_CMD, FALSE, FALSE },
200 { "tls_auth", 0, TLS_AUTH_CMD, FALSE, FALSE },
203 /* If you change anything above here, also fix the definitions below. */
205 { "mail from:", sizeof("mail from:")-1, MAIL_CMD, TRUE, TRUE },
206 { "rcpt to:", sizeof("rcpt to:")-1, RCPT_CMD, TRUE, TRUE },
207 { "data", sizeof("data")-1, DATA_CMD, FALSE, TRUE },
208 { "bdat", sizeof("bdat")-1, BDAT_CMD, TRUE, TRUE },
209 { "quit", sizeof("quit")-1, QUIT_CMD, FALSE, TRUE },
210 { "noop", sizeof("noop")-1, NOOP_CMD, TRUE, FALSE },
211 { "etrn", sizeof("etrn")-1, ETRN_CMD, TRUE, FALSE },
212 { "vrfy", sizeof("vrfy")-1, VRFY_CMD, TRUE, FALSE },
213 { "expn", sizeof("expn")-1, EXPN_CMD, TRUE, FALSE },
214 { "help", sizeof("help")-1, HELP_CMD, TRUE, FALSE }
217 static smtp_cmd_list *cmd_list_end =
218 cmd_list + sizeof(cmd_list)/sizeof(smtp_cmd_list);
220 #define CMD_LIST_RSET 0
221 #define CMD_LIST_HELO 1
222 #define CMD_LIST_EHLO 2
223 #define CMD_LIST_AUTH 3
224 #define CMD_LIST_STARTTLS 4
225 #define CMD_LIST_TLS_AUTH 5
227 /* This list of names is used for performing the smtp_no_mail logging action.
228 It must be kept in step with the SCH_xxx enumerations. */
230 uschar * smtp_names[] =
232 US"NONE", US"AUTH", US"DATA", US"BDAT", US"EHLO", US"ETRN", US"EXPN",
233 US"HELO", US"HELP", US"MAIL", US"NOOP", US"QUIT", US"RCPT", US"RSET",
234 US"STARTTLS", US"VRFY" };
236 static uschar *protocols_local[] = {
237 US"local-smtp", /* HELO */
238 US"local-smtps", /* The rare case EHLO->STARTTLS->HELO */
239 US"local-esmtp", /* EHLO */
240 US"local-esmtps", /* EHLO->STARTTLS->EHLO */
241 US"local-esmtpa", /* EHLO->AUTH */
242 US"local-esmtpsa" /* EHLO->STARTTLS->EHLO->AUTH */
244 static uschar *protocols[] = {
246 US"smtps", /* The rare case EHLO->STARTTLS->HELO */
247 US"esmtp", /* EHLO */
248 US"esmtps", /* EHLO->STARTTLS->EHLO */
249 US"esmtpa", /* EHLO->AUTH */
250 US"esmtpsa" /* EHLO->STARTTLS->EHLO->AUTH */
255 #define pcrpted 1 /* added to pextend or pnormal */
256 #define pauthed 2 /* added to pextend */
258 /* Sanity check and validate optional args to MAIL FROM: envelope */
261 ENV_MAIL_OPT_SIZE, ENV_MAIL_OPT_BODY, ENV_MAIL_OPT_AUTH,
265 ENV_MAIL_OPT_RET, ENV_MAIL_OPT_ENVID,
271 uschar * name; /* option requested during MAIL cmd */
272 int value; /* enum type */
273 BOOL need_value; /* TRUE requires value (name=value pair format)
274 FALSE is a singleton */
276 static env_mail_type_t env_mail_type_list[] = {
277 { US"SIZE", ENV_MAIL_OPT_SIZE, TRUE },
278 { US"BODY", ENV_MAIL_OPT_BODY, TRUE },
279 { US"AUTH", ENV_MAIL_OPT_AUTH, TRUE },
281 { US"PRDR", ENV_MAIL_OPT_PRDR, FALSE },
283 { US"RET", ENV_MAIL_OPT_RET, TRUE },
284 { US"ENVID", ENV_MAIL_OPT_ENVID, TRUE },
286 { US"SMTPUTF8",ENV_MAIL_OPT_UTF8, FALSE }, /* rfc6531 */
288 /* keep this the last entry */
289 { US"NULL", ENV_MAIL_OPT_NULL, FALSE },
292 /* When reading SMTP from a remote host, we have to use our own versions of the
293 C input-reading functions, in order to be able to flush the SMTP output only
294 when about to read more data from the socket. This is the only way to get
295 optimal performance when the client is using pipelining. Flushing for every
296 command causes a separate packet and reply packet each time; saving all the
297 responses up (when pipelining) combines them into one packet and one response.
299 For simplicity, these functions are used for *all* SMTP input, not only when
300 receiving over a socket. However, after setting up a secure socket (SSL), input
301 is read via the OpenSSL library, and another set of functions is used instead
304 These functions are set in the receive_getc etc. variables and called with the
305 same interface as the C functions. However, since there can only ever be
306 one incoming SMTP call, we just use a single buffer and flags. There is no need
307 to implement a complicated private FILE-like structure.*/
309 static uschar *smtp_inbuffer;
310 static uschar *smtp_inptr;
311 static uschar *smtp_inend;
312 static int smtp_had_eof;
313 static int smtp_had_error;
316 /* forward declarations */
317 static int smtp_read_command(BOOL check_sync, unsigned buffer_lim);
318 static int synprot_error(int type, int code, uschar *data, uschar *errmess);
319 static void smtp_quit_handler(uschar **, uschar **);
320 static void smtp_rset_handler(void);
322 /*************************************************
323 * Recheck synchronization *
324 *************************************************/
326 /* Synchronization checks can never be perfect because a packet may be on its
327 way but not arrived when the check is done. Normally, the checks happen when
328 commands are read: Exim ensures that there is no more input in the input buffer.
329 In normal cases, the response to the command will be fast, and there is no
332 However, for some commands an ACL is run, and that can include delays. In those
333 cases, it is useful to do another check on the input just before sending the
334 response. This also applies at the start of a connection. This function does
335 that check by means of the select() function, as long as the facility is not
336 disabled or inappropriate. A failure of select() is ignored.
338 When there is unwanted input, we read it so that it appears in the log of the
342 Returns: TRUE if all is well; FALSE if there is input pending
346 wouldblock_reading(void)
350 struct timeval tzero = {.tv_sec = 0, .tv_usec = 0};
353 if (tls_in.active.sock >= 0)
354 return !tls_could_read();
357 if (smtp_inptr < smtp_inend)
360 fd = fileno(smtp_in);
363 rc = select(fd + 1, (SELECT_ARG2_TYPE *)&fds, NULL, NULL, &tzero);
365 if (rc <= 0) return TRUE; /* Not ready to read */
366 rc = smtp_getc(GETC_BUFFER_UNLIMITED);
367 if (rc < 0) return TRUE; /* End of file or error */
376 if (!smtp_enforce_sync || !sender_host_address || f.sender_host_notsocket)
379 return wouldblock_reading();
383 /* If there's input waiting (and we're doing pipelineing) then we can pipeline
384 a reponse with the one following. */
387 pipeline_response(void)
389 if ( !smtp_enforce_sync || !sender_host_address
390 || f.sender_host_notsocket || !f.smtp_in_pipelining_advertised)
393 if (wouldblock_reading()) return FALSE;
394 f.smtp_in_pipelining_used = TRUE;
399 #ifndef DISABLE_PIPE_CONNECT
401 pipeline_connect_sends(void)
403 if (!sender_host_address || f.sender_host_notsocket || !fl.pipe_connect_acceptable)
406 if (wouldblock_reading()) return FALSE;
407 f.smtp_in_early_pipe_used = TRUE;
412 /*************************************************
413 * Log incomplete transactions *
414 *************************************************/
416 /* This function is called after a transaction has been aborted by RSET, QUIT,
417 connection drops or other errors. It logs the envelope information received
418 so far in order to preserve address verification attempts.
420 Argument: string to indicate what aborted the transaction
425 incomplete_transaction_log(uschar *what)
427 if (!sender_address /* No transaction in progress */
428 || !LOGGING(smtp_incomplete_transaction))
431 /* Build list of recipients for logging */
433 if (recipients_count > 0)
435 raw_recipients = store_get(recipients_count * sizeof(uschar *), FALSE);
436 for (int i = 0; i < recipients_count; i++)
437 raw_recipients[i] = recipients_list[i].address;
438 raw_recipients_count = recipients_count;
441 log_write(L_smtp_incomplete_transaction, LOG_MAIN|LOG_SENDER|LOG_RECIPIENTS,
442 "%s incomplete transaction (%s)", host_and_ident(TRUE), what);
449 smtp_command_timeout_exit(void)
451 log_write(L_lost_incoming_connection,
452 LOG_MAIN, "SMTP command timeout on%s connection from %s",
453 tls_in.active.sock >= 0 ? " TLS" : "", host_and_ident(FALSE));
454 if (smtp_batched_input)
455 moan_smtp_batch(NULL, "421 SMTP command timeout"); /* Does not return */
456 smtp_notquit_exit(US"command-timeout", US"421",
457 US"%s: SMTP command timeout - closing connection",
458 smtp_active_hostname);
459 exim_exit(EXIT_FAILURE);
463 smtp_command_sigterm_exit(void)
465 log_write(0, LOG_MAIN, "%s closed after SIGTERM", smtp_get_connection_info());
466 if (smtp_batched_input)
467 moan_smtp_batch(NULL, "421 SIGTERM received"); /* Does not return */
468 smtp_notquit_exit(US"signal-exit", US"421",
469 US"%s: Service not available - closing connection", smtp_active_hostname);
470 exim_exit(EXIT_FAILURE);
474 smtp_data_timeout_exit(void)
476 log_write(L_lost_incoming_connection,
477 LOG_MAIN, "SMTP data timeout (message abandoned) on connection from %s F=<%s>",
478 sender_fullhost ? sender_fullhost : US"local process", sender_address);
479 receive_bomb_out(US"data-timeout", US"SMTP incoming data timeout");
480 /* Does not return */
484 smtp_data_sigint_exit(void)
486 log_write(0, LOG_MAIN, "%s closed after %s",
487 smtp_get_connection_info(), had_data_sigint == SIGTERM ? "SIGTERM":"SIGINT");
488 receive_bomb_out(US"signal-exit",
489 US"Service not available - SIGTERM or SIGINT received");
490 /* Does not return */
495 /* Refill the buffer, and notify DKIM verification code.
496 Return false for error or EOF.
500 smtp_refill(unsigned lim)
503 if (!smtp_out) return FALSE;
505 if (smtp_receive_timeout > 0) ALARM(smtp_receive_timeout);
507 /* Limit amount read, so non-message data is not fed to DKIM.
508 Take care to not touch the safety NUL at the end of the buffer. */
510 rc = read(fileno(smtp_in), smtp_inbuffer, MIN(IN_BUFFER_SIZE-1, lim));
512 if (smtp_receive_timeout > 0) ALARM_CLR(0);
515 /* Must put the error text in fixed store, because this might be during
516 header reading, where it releases unused store above the header. */
519 if (had_command_timeout) /* set by signal handler */
520 smtp_command_timeout_exit(); /* does not return */
521 if (had_command_sigterm)
522 smtp_command_sigterm_exit();
523 if (had_data_timeout)
524 smtp_data_timeout_exit();
526 smtp_data_sigint_exit();
528 smtp_had_error = save_errno;
529 smtp_read_error = string_copy_perm(
530 string_sprintf(" (error: %s)", strerror(save_errno)), FALSE);
537 dkim_exim_verify_feed(smtp_inbuffer, rc);
539 smtp_inend = smtp_inbuffer + rc;
540 smtp_inptr = smtp_inbuffer;
544 /*************************************************
545 * SMTP version of getc() *
546 *************************************************/
548 /* This gets the next byte from the SMTP input buffer. If the buffer is empty,
549 it flushes the output, and refills the buffer, with a timeout. The signal
550 handler is set appropriately by the calling function. This function is not used
551 after a connection has negotiated itself into an TLS/SSL state.
553 Arguments: lim Maximum amount to read/buffer
554 Returns: the next character or EOF
558 smtp_getc(unsigned lim)
560 if (smtp_inptr >= smtp_inend)
561 if (!smtp_refill(lim))
563 return *smtp_inptr++;
567 smtp_getbuf(unsigned * len)
572 if (smtp_inptr >= smtp_inend)
573 if (!smtp_refill(*len))
574 { *len = 0; return NULL; }
576 if ((size = smtp_inend - smtp_inptr) > *len) size = *len;
587 int n = smtp_inend - smtp_inptr;
588 if (chunking_state == CHUNKING_LAST && chunking_data_left < n)
589 n = chunking_data_left;
591 dkim_exim_verify_feed(smtp_inptr, n);
596 /* Get a byte from the smtp input, in CHUNKING mode. Handle ack of the
597 previous BDAT chunk and getting new ones when we run out. Uses the
598 underlying smtp_getc or tls_getc both for that and for getting the
599 (buffered) data byte. EOD signals (an expected) no further data.
600 ERR signals a protocol error, and EOF a closed input stream.
602 Called from read_bdat_smtp() in receive.c for the message body, but also
603 by the headers read loop in receive_msg(); manipulates chunking_state
604 to handle the BDAT command/response.
605 Placed here due to the correlation with the above smtp_getc(), which it wraps,
606 and also by the need to do smtp command/response handling.
608 Arguments: lim (ignored)
609 Returns: the next character or ERR, EOD or EOF
613 bdat_getc(unsigned lim)
615 uschar * user_msg = NULL;
624 if (chunking_data_left > 0)
625 return lwr_receive_getc(chunking_data_left--);
627 receive_getc = lwr_receive_getc;
628 receive_getbuf = lwr_receive_getbuf;
629 receive_ungetc = lwr_receive_ungetc;
631 dkim_save = dkim_collect_input;
632 dkim_collect_input = 0;
635 /* Unless PIPELINING was offered, there should be no next command
636 until after we ack that chunk */
638 if (!f.smtp_in_pipelining_advertised && !check_sync())
640 unsigned n = smtp_inend - smtp_inptr;
643 incomplete_transaction_log(US"sync failure");
644 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP protocol synchronization error "
645 "(next input sent too soon: pipelining was not advertised): "
646 "rejected \"%s\" %s next input=\"%s\"%s",
647 smtp_cmd_buffer, host_and_ident(TRUE),
648 string_printing(string_copyn(smtp_inptr, n)),
649 smtp_inend - smtp_inptr > n ? "..." : "");
650 (void) synprot_error(L_smtp_protocol_error, 554, NULL,
651 US"SMTP synchronization error");
652 goto repeat_until_rset;
655 /* If not the last, ack the received chunk. The last response is delayed
656 until after the data ACL decides on it */
658 if (chunking_state == CHUNKING_LAST)
661 dkim_exim_verify_feed(NULL, 0); /* notify EOD */
666 smtp_printf("250 %u byte chunk received\r\n", FALSE, chunking_datasize);
667 chunking_state = CHUNKING_OFFERED;
668 DEBUG(D_receive) debug_printf("chunking state %d\n", (int)chunking_state);
670 /* Expect another BDAT cmd from input. RFC 3030 says nothing about
671 QUIT, RSET or NOOP but handling them seems obvious */
674 switch(smtp_read_command(TRUE, 1))
677 (void) synprot_error(L_smtp_protocol_error, 503, NULL,
678 US"only BDAT permissible after non-LAST BDAT");
681 switch(smtp_read_command(TRUE, 1))
683 case QUIT_CMD: smtp_quit_handler(&user_msg, &log_msg); /*FALLTHROUGH */
684 case EOF_CMD: return EOF;
685 case RSET_CMD: smtp_rset_handler(); return ERR;
686 default: if (synprot_error(L_smtp_protocol_error, 503, NULL,
687 US"only RSET accepted now") > 0)
689 goto repeat_until_rset;
693 smtp_quit_handler(&user_msg, &log_msg);
704 smtp_printf("250 OK\r\n", FALSE);
711 if (sscanf(CS smtp_cmd_data, "%u %n", &chunking_datasize, &n) < 1)
713 (void) synprot_error(L_smtp_protocol_error, 501, NULL,
714 US"missing size for BDAT command");
717 chunking_state = strcmpic(smtp_cmd_data+n, US"LAST") == 0
718 ? CHUNKING_LAST : CHUNKING_ACTIVE;
719 chunking_data_left = chunking_datasize;
720 DEBUG(D_receive) debug_printf("chunking state %d, %d bytes\n",
721 (int)chunking_state, chunking_data_left);
723 if (chunking_datasize == 0)
724 if (chunking_state == CHUNKING_LAST)
728 (void) synprot_error(L_smtp_protocol_error, 504, NULL,
729 US"zero size for BDAT command");
730 goto repeat_until_rset;
733 receive_getc = bdat_getc;
734 receive_getbuf = bdat_getbuf; /* r~getbuf is never actually used */
735 receive_ungetc = bdat_ungetc;
737 dkim_collect_input = dkim_save;
739 break; /* to top of main loop */
746 bdat_getbuf(unsigned * len)
750 if (chunking_data_left <= 0)
751 { *len = 0; return NULL; }
753 if (*len > chunking_data_left) *len = chunking_data_left;
754 buf = lwr_receive_getbuf(len); /* Either smtp_getbuf or tls_getbuf */
755 chunking_data_left -= *len;
760 bdat_flush_data(void)
762 while (chunking_data_left)
764 unsigned n = chunking_data_left;
765 if (!bdat_getbuf(&n)) break;
768 receive_getc = lwr_receive_getc;
769 receive_getbuf = lwr_receive_getbuf;
770 receive_ungetc = lwr_receive_ungetc;
772 if (chunking_state != CHUNKING_LAST)
774 chunking_state = CHUNKING_OFFERED;
775 DEBUG(D_receive) debug_printf("chunking state %d\n", (int)chunking_state);
782 /*************************************************
783 * SMTP version of ungetc() *
784 *************************************************/
786 /* Puts a character back in the input buffer. Only ever
792 Returns: the character
806 chunking_data_left++;
807 return lwr_receive_ungetc(ch);
812 /*************************************************
813 * SMTP version of feof() *
814 *************************************************/
816 /* Tests for a previous EOF
819 Returns: non-zero if the eof flag is set
831 /*************************************************
832 * SMTP version of ferror() *
833 *************************************************/
835 /* Tests for a previous read error, and returns with errno
836 restored to what it was when the error was detected.
839 Returns: non-zero if the error flag is set
845 errno = smtp_had_error;
846 return smtp_had_error;
851 /*************************************************
852 * Test for characters in the SMTP buffer *
853 *************************************************/
855 /* Used at the end of a message
864 return smtp_inptr < smtp_inend;
869 /*************************************************
870 * Write formatted string to SMTP channel *
871 *************************************************/
873 /* This is a separate function so that we don't have to repeat everything for
874 TLS support or debugging. It is global so that the daemon and the
875 authentication functions can use it. It does not return any error indication,
876 because major problems such as dropped connections won't show up till an output
877 flush for non-TLS connections. The smtp_fflush() function is available for
878 checking that: for convenience, TLS output errors are remembered here so that
879 they are also picked up later by smtp_fflush().
881 This function is exposed to the local_scan API; do not change the signature.
885 more further data expected
886 ... optional arguments
892 smtp_printf(const char *format, BOOL more, ...)
897 smtp_vprintf(format, more, ap);
901 /* This is split off so that verify.c:respond_printf() can, in effect, call
902 smtp_printf(), bearing in mind that in C a vararg function can't directly
903 call another vararg function, only a function which accepts a va_list.
905 This function is exposed to the local_scan API; do not change the signature.
907 /*XXX consider passing caller-info in, for string_vformat-onward */
910 smtp_vprintf(const char *format, BOOL more, va_list ap)
912 gstring gs = { .size = big_buffer_size, .ptr = 0, .s = big_buffer };
915 /* Use taint-unchecked routines for writing into big_buffer, trusting
916 that we'll never expand it. */
918 yield = !! string_vformat(&gs, SVFMT_TAINT_NOCHK, format, ap);
919 string_from_gstring(&gs);
923 uschar *msg_copy, *cr, *end;
924 msg_copy = string_copy(gs.s);
925 end = msg_copy + gs.ptr;
926 while ((cr = Ustrchr(msg_copy, '\r')) != NULL) /* lose CRs */
927 memmove(cr, cr + 1, (end--) - cr);
928 debug_printf("SMTP>> %s", msg_copy);
933 log_write(0, LOG_MAIN|LOG_PANIC, "string too large in smtp_printf()");
934 smtp_closedown(US"Unexpected error");
935 exim_exit(EXIT_FAILURE);
938 /* If this is the first output for a (non-batch) RCPT command, see if all RCPTs
939 have had the same. Note: this code is also present in smtp_respond(). It would
940 be tidier to have it only in one place, but when it was added, it was easier to
941 do it that way, so as not to have to mess with the code for the RCPT command,
942 which sometimes uses smtp_printf() and sometimes smtp_respond(). */
944 if (fl.rcpt_in_progress)
946 if (rcpt_smtp_response == NULL)
947 rcpt_smtp_response = string_copy(big_buffer);
948 else if (fl.rcpt_smtp_response_same &&
949 Ustrcmp(rcpt_smtp_response, big_buffer) != 0)
950 fl.rcpt_smtp_response_same = FALSE;
951 fl.rcpt_in_progress = FALSE;
954 /* Now write the string */
958 tls_in.active.sock >= 0 ? (tls_write(NULL, gs.s, gs.ptr, more) < 0) :
960 (fwrite(gs.s, gs.ptr, 1, smtp_out) == 0)
962 smtp_write_error = -1;
967 /*************************************************
968 * Flush SMTP out and check for error *
969 *************************************************/
971 /* This function isn't currently used within Exim (it detects errors when it
972 tries to read the next SMTP input), but is available for use in local_scan().
973 It flushes the output and checks for errors.
976 Returns: 0 for no error; -1 after an error
982 if (tls_in.active.sock < 0 && fflush(smtp_out) != 0) smtp_write_error = -1;
986 tls_in.active.sock >= 0 ? (tls_write(NULL, NULL, 0, FALSE) < 0) :
988 (fflush(smtp_out) != 0)
990 smtp_write_error = -1;
992 return smtp_write_error;
997 /*************************************************
998 * SMTP command read timeout *
999 *************************************************/
1001 /* Signal handler for timing out incoming SMTP commands. This attempts to
1004 Argument: signal number (SIGALRM)
1009 command_timeout_handler(int sig)
1011 had_command_timeout = sig;
1016 /*************************************************
1017 * SIGTERM received *
1018 *************************************************/
1020 /* Signal handler for handling SIGTERM. Again, try to finish tidily.
1022 Argument: signal number (SIGTERM)
1027 command_sigterm_handler(int sig)
1029 had_command_sigterm = sig;
1035 #ifdef SUPPORT_PROXY
1036 /*************************************************
1037 * Check if host is required proxy host *
1038 *************************************************/
1039 /* The function determines if inbound host will be a regular smtp host
1040 or if it is configured that it must use Proxy Protocol. A local
1048 check_proxy_protocol_host()
1052 if ( sender_host_address
1053 && (rc = verify_check_this_host(CUSS &hosts_proxy, NULL, NULL,
1054 sender_host_address, NULL)) == OK)
1057 debug_printf("Detected proxy protocol configured host\n");
1058 proxy_session = TRUE;
1060 return proxy_session;
1064 /*************************************************
1065 * Read data until newline or end of buffer *
1066 *************************************************/
1067 /* While SMTP is server-speaks-first, TLS is client-speaks-first, so we can't
1068 read an entire buffer and assume there will be nothing past a proxy protocol
1069 header. Our approach normally is to use stdio, but again that relies upon
1070 "STARTTLS\r\n" and a server response before the client starts TLS handshake, or
1071 reading _nothing_ before client TLS handshake. So we don't want to use the
1072 usual buffering reads which may read enough to block TLS starting.
1074 So unfortunately we're down to "read one byte at a time, with a syscall each,
1075 and expect a little overhead", for all proxy-opened connections which are v1,
1076 just to handle the TLS-on-connect case. Since SSL functions wrap the
1077 underlying fd, we can't assume that we can feed them any already-read content.
1079 We need to know where to read to, the max capacity, and we'll read until we
1080 get a CR and one more character. Let the caller scream if it's CR+!LF.
1082 Return the amount read.
1086 swallow_until_crlf(int fd, uschar *base, int already, int capacity)
1088 uschar *to = base + already;
1094 /* For "PROXY UNKNOWN\r\n" we, at time of writing, expect to have read
1095 up through the \r; for the _normal_ case, we haven't yet seen the \r. */
1097 cr = memchr(base, '\r', already);
1100 if ((cr - base) < already - 1)
1102 /* \r and presumed \n already within what we have; probably not
1103 actually proxy protocol, but abort cleanly. */
1106 /* \r is last character read, just need one more. */
1110 while (capacity > 0)
1112 do { ret = read(fd, to, 1); } while (ret == -1 && errno == EINTR && !had_command_timeout);
1124 /* reached end without having room for a final newline, abort */
1129 /*************************************************
1130 * Setup host for proxy protocol *
1131 *************************************************/
1132 /* The function configures the connection based on a header from the
1133 inbound host to use Proxy Protocol. The specification is very exact
1134 so exit with an error if do not find the exact required pieces. This
1135 includes an incorrect number of spaces separating args.
1138 Returns: Boolean success
1142 setup_proxy_protocol_host()
1154 struct { /* TCP/UDP over IPv4, len = 12 */
1160 struct { /* TCP/UDP over IPv6, len = 36 */
1161 uint8_t src_addr[16];
1162 uint8_t dst_addr[16];
1166 struct { /* AF_UNIX sockets, len = 216 */
1167 uschar src_addr[108];
1168 uschar dst_addr[108];
1174 /* Temp variables used in PPv2 address:port parsing */
1176 char tmpip[INET_ADDRSTRLEN];
1177 struct sockaddr_in tmpaddr;
1178 char tmpip6[INET6_ADDRSTRLEN];
1179 struct sockaddr_in6 tmpaddr6;
1181 /* We can't read "all data until end" because while SMTP is
1182 server-speaks-first, the TLS handshake is client-speaks-first, so for
1183 TLS-on-connect ports the proxy protocol header will usually be immediately
1184 followed by a TLS handshake, and with N TLS libraries, we can't reliably
1185 reinject data for reading by those. So instead we first read "enough to be
1186 safely read within the header, and figure out how much more to read".
1187 For v1 we will later read to the end-of-line, for v2 we will read based upon
1190 The v2 sig is 12 octets, and another 4 gets us the length, so we know how much
1191 data is needed total. For v1, where the line looks like:
1192 PROXY TCPn L3src L3dest SrcPort DestPort \r\n
1194 However, for v1 there's also `PROXY UNKNOWN\r\n` which is only 15 octets.
1195 We seem to support that. So, if we read 14 octets then we can tell if we're
1196 v2 or v1. If we're v1, we can continue reading as normal.
1198 If we're v2, we can't slurp up the entire header. We need the length in the
1199 15th & 16th octets, then to read everything after that.
1201 So to safely handle v1 and v2, with client-sent-first supported correctly,
1202 we have to do a minimum of 3 read calls, not 1. Eww.
1205 #define PROXY_INITIAL_READ 14
1206 #define PROXY_V2_HEADER_SIZE 16
1207 #if PROXY_INITIAL_READ > PROXY_V2_HEADER_SIZE
1208 # error Code bug in sizes of data to read for proxy usage
1213 int fd = fileno(smtp_in);
1214 const char v2sig[12] = "\x0D\x0A\x0D\x0A\x00\x0D\x0A\x51\x55\x49\x54\x0A";
1215 uschar * iptype; /* To display debug info */
1216 socklen_t vslen = sizeof(struct timeval);
1219 os_non_restarting_signal(SIGALRM, command_timeout_handler);
1220 ALARM(proxy_protocol_timeout);
1224 /* The inbound host was declared to be a Proxy Protocol host, so
1225 don't do a PEEK into the data, actually slurp up enough to be
1226 "safe". Can't take it all because TLS-on-connect clients follow
1227 immediately with TLS handshake. */
1228 ret = read(fd, &hdr, PROXY_INITIAL_READ);
1230 while (ret == -1 && errno == EINTR && !had_command_timeout);
1235 /* For v2, handle reading the length, and then the rest. */
1236 if ((ret == PROXY_INITIAL_READ) && (memcmp(&hdr.v2, v2sig, sizeof(v2sig)) == 0))
1241 /* First get the length fields. */
1244 retmore = read(fd, (uschar*)&hdr + ret, PROXY_V2_HEADER_SIZE - PROXY_INITIAL_READ);
1245 } while (retmore == -1 && errno == EINTR && !had_command_timeout);
1250 ver = (hdr.v2.ver_cmd & 0xf0) >> 4;
1252 /* May 2014: haproxy combined the version and command into one byte to
1253 allow two full bytes for the length field in order to proxy SSL
1254 connections. SSL Proxy is not supported in this version of Exim, but
1255 must still separate values here. */
1259 DEBUG(D_receive) debug_printf("Invalid Proxy Protocol version: %d\n", ver);
1263 /* The v2 header will always be 16 bytes per the spec. */
1264 size = 16 + ntohs(hdr.v2.len);
1265 DEBUG(D_receive) debug_printf("Detected PROXYv2 header, size %d (limit %d)\n",
1266 size, (int)sizeof(hdr));
1268 /* We should now have 16 octets (PROXY_V2_HEADER_SIZE), and we know the total
1269 amount that we need. Double-check that the size is not unreasonable, then
1271 if (size > sizeof(hdr))
1273 DEBUG(D_receive) debug_printf("PROXYv2 header size unreasonably large; security attack?\n");
1281 retmore = read(fd, (uschar*)&hdr + ret, size-ret);
1282 } while (retmore == -1 && errno == EINTR && !had_command_timeout);
1286 DEBUG(D_receive) debug_printf("PROXYv2: have %d/%d required octets\n", ret, size);
1287 } while (ret < size);
1289 } /* end scope for getting rest of data for v2 */
1291 /* At this point: if PROXYv2, we've read the exact size required for all data;
1292 if PROXYv1 then we've read "less than required for any valid line" and should
1295 if (ret >= 16 && memcmp(&hdr.v2, v2sig, 12) == 0)
1297 uint8_t cmd = (hdr.v2.ver_cmd & 0x0f);
1301 case 0x01: /* PROXY command */
1304 case 0x11: /* TCPv4 address type */
1306 tmpaddr.sin_addr.s_addr = hdr.v2.addr.ip4.src_addr;
1307 inet_ntop(AF_INET, &tmpaddr.sin_addr, CS &tmpip, sizeof(tmpip));
1308 if (!string_is_ip_address(US tmpip, NULL))
1310 DEBUG(D_receive) debug_printf("Invalid %s source IP\n", iptype);
1313 proxy_local_address = sender_host_address;
1314 sender_host_address = string_copy(US tmpip);
1315 tmpport = ntohs(hdr.v2.addr.ip4.src_port);
1316 proxy_local_port = sender_host_port;
1317 sender_host_port = tmpport;
1318 /* Save dest ip/port */
1319 tmpaddr.sin_addr.s_addr = hdr.v2.addr.ip4.dst_addr;
1320 inet_ntop(AF_INET, &tmpaddr.sin_addr, CS &tmpip, sizeof(tmpip));
1321 if (!string_is_ip_address(US tmpip, NULL))
1323 DEBUG(D_receive) debug_printf("Invalid %s dest port\n", iptype);
1326 proxy_external_address = string_copy(US tmpip);
1327 tmpport = ntohs(hdr.v2.addr.ip4.dst_port);
1328 proxy_external_port = tmpport;
1330 case 0x21: /* TCPv6 address type */
1332 memmove(tmpaddr6.sin6_addr.s6_addr, hdr.v2.addr.ip6.src_addr, 16);
1333 inet_ntop(AF_INET6, &tmpaddr6.sin6_addr, CS &tmpip6, sizeof(tmpip6));
1334 if (!string_is_ip_address(US tmpip6, NULL))
1336 DEBUG(D_receive) debug_printf("Invalid %s source IP\n", iptype);
1339 proxy_local_address = sender_host_address;
1340 sender_host_address = string_copy(US tmpip6);
1341 tmpport = ntohs(hdr.v2.addr.ip6.src_port);
1342 proxy_local_port = sender_host_port;
1343 sender_host_port = tmpport;
1344 /* Save dest ip/port */
1345 memmove(tmpaddr6.sin6_addr.s6_addr, hdr.v2.addr.ip6.dst_addr, 16);
1346 inet_ntop(AF_INET6, &tmpaddr6.sin6_addr, CS &tmpip6, sizeof(tmpip6));
1347 if (!string_is_ip_address(US tmpip6, NULL))
1349 DEBUG(D_receive) debug_printf("Invalid %s dest port\n", iptype);
1352 proxy_external_address = string_copy(US tmpip6);
1353 tmpport = ntohs(hdr.v2.addr.ip6.dst_port);
1354 proxy_external_port = tmpport;
1358 debug_printf("Unsupported PROXYv2 connection type: 0x%02x\n",
1362 /* Unsupported protocol, keep local connection address */
1364 case 0x00: /* LOCAL command */
1365 /* Keep local connection address for LOCAL */
1370 debug_printf("Unsupported PROXYv2 command: 0x%x\n", cmd);
1374 else if (ret >= 8 && memcmp(hdr.v1.line, "PROXY", 5) == 0)
1378 uschar *sp; /* Utility variables follow */
1383 /* get the rest of the line */
1384 r2 = swallow_until_crlf(fd, (uschar*)&hdr, ret, sizeof(hdr)-ret);
1389 p = string_copy(hdr.v1.line);
1390 end = memchr(p, '\r', ret - 1);
1392 if (!end || (end == (uschar*)&hdr + ret) || end[1] != '\n')
1394 DEBUG(D_receive) debug_printf("Partial or invalid PROXY header\n");
1397 *end = '\0'; /* Terminate the string */
1398 size = end + 2 - p; /* Skip header + CRLF */
1399 DEBUG(D_receive) debug_printf("Detected PROXYv1 header\n");
1400 DEBUG(D_receive) debug_printf("Bytes read not within PROXY header: %d\n", ret - size);
1401 /* Step through the string looking for the required fields. Ensure
1402 strict adherence to required formatting, exit for any error. */
1404 if (!isspace(*(p++)))
1406 DEBUG(D_receive) debug_printf("Missing space after PROXY command\n");
1409 if (!Ustrncmp(p, CCS"TCP4", 4))
1411 else if (!Ustrncmp(p,CCS"TCP6", 4))
1413 else if (!Ustrncmp(p,CCS"UNKNOWN", 7))
1415 iptype = US"Unknown";
1420 DEBUG(D_receive) debug_printf("Invalid TCP type\n");
1424 p += Ustrlen(iptype);
1425 if (!isspace(*(p++)))
1427 DEBUG(D_receive) debug_printf("Missing space after TCP4/6 command\n");
1430 /* Find the end of the arg */
1431 if ((sp = Ustrchr(p, ' ')) == NULL)
1434 debug_printf("Did not find proxied src %s\n", iptype);
1438 if(!string_is_ip_address(p, NULL))
1441 debug_printf("Proxied src arg is not an %s address\n", iptype);
1444 proxy_local_address = sender_host_address;
1445 sender_host_address = p;
1447 if ((sp = Ustrchr(p, ' ')) == NULL)
1450 debug_printf("Did not find proxy dest %s\n", iptype);
1454 if(!string_is_ip_address(p, NULL))
1457 debug_printf("Proxy dest arg is not an %s address\n", iptype);
1460 proxy_external_address = p;
1462 if ((sp = Ustrchr(p, ' ')) == NULL)
1464 DEBUG(D_receive) debug_printf("Did not find proxied src port\n");
1468 tmp_port = strtol(CCS p, &endc, 10);
1469 if (*endc || tmp_port == 0)
1472 debug_printf("Proxied src port '%s' not an integer\n", p);
1475 proxy_local_port = sender_host_port;
1476 sender_host_port = tmp_port;
1478 if ((sp = Ustrchr(p, '\0')) == NULL)
1480 DEBUG(D_receive) debug_printf("Did not find proxy dest port\n");
1483 tmp_port = strtol(CCS p, &endc, 10);
1484 if (*endc || tmp_port == 0)
1487 debug_printf("Proxy dest port '%s' not an integer\n", p);
1490 proxy_external_port = tmp_port;
1491 /* Already checked for /r /n above. Good V1 header received. */
1495 /* Wrong protocol */
1496 DEBUG(D_receive) debug_printf("Invalid proxy protocol version negotiation\n");
1497 (void) swallow_until_crlf(fd, (uschar*)&hdr, ret, sizeof(hdr)-ret);
1503 debug_printf("Valid %s sender from Proxy Protocol header\n", iptype);
1504 yield = proxy_session;
1506 /* Don't flush any potential buffer contents. Any input on proxyfail
1507 should cause a synchronization failure */
1510 DEBUG(D_receive) if (had_command_timeout)
1511 debug_printf("Timeout while reading proxy header\n");
1516 sender_host_name = NULL;
1517 (void) host_name_lookup();
1518 host_build_sender_fullhost();
1522 f.proxy_session_failed = TRUE;
1524 debug_printf("Failure to extract proxied host, only QUIT allowed\n");
1532 /*************************************************
1533 * Read one command line *
1534 *************************************************/
1536 /* Strictly, SMTP commands coming over the net are supposed to end with CRLF.
1537 There are sites that don't do this, and in any case internal SMTP probably
1538 should check only for LF. Consequently, we check here for LF only. The line
1539 ends up with [CR]LF removed from its end. If we get an overlong line, treat as
1540 an unknown command. The command is read into the global smtp_cmd_buffer so that
1541 it is available via $smtp_command.
1543 The character reading routine sets up a timeout for each block actually read
1544 from the input (which may contain more than one command). We set up a special
1545 signal handler that closes down the session on a timeout. Control does not
1546 return when it runs.
1549 check_sync if TRUE, check synchronization rules if global option is TRUE
1550 buffer_lim maximum to buffer in lower layer
1552 Returns: a code identifying the command (enumerated above)
1556 smtp_read_command(BOOL check_sync, unsigned buffer_lim)
1560 BOOL hadnull = FALSE;
1562 had_command_timeout = 0;
1563 os_non_restarting_signal(SIGALRM, command_timeout_handler);
1565 while ((c = (receive_getc)(buffer_lim)) != '\n' && c != EOF)
1567 if (ptr >= SMTP_CMD_BUFFER_SIZE)
1569 os_non_restarting_signal(SIGALRM, sigalrm_handler);
1577 smtp_cmd_buffer[ptr++] = c;
1580 receive_linecount++; /* For BSMTP errors */
1581 os_non_restarting_signal(SIGALRM, sigalrm_handler);
1583 /* If hit end of file, return pseudo EOF command. Whether we have a
1584 part-line already read doesn't matter, since this is an error state. */
1586 if (c == EOF) return EOF_CMD;
1588 /* Remove any CR and white space at the end of the line, and terminate the
1591 while (ptr > 0 && isspace(smtp_cmd_buffer[ptr-1])) ptr--;
1592 smtp_cmd_buffer[ptr] = 0;
1594 DEBUG(D_receive) debug_printf("SMTP<< %s\n", smtp_cmd_buffer);
1596 /* NULLs are not allowed in SMTP commands */
1598 if (hadnull) return BADCHAR_CMD;
1600 /* Scan command list and return identity, having set the data pointer
1601 to the start of the actual data characters. Check for SMTP synchronization
1604 for (smtp_cmd_list * p = cmd_list; p < cmd_list_end; p++)
1606 #ifdef SUPPORT_PROXY
1607 /* Only allow QUIT command if Proxy Protocol parsing failed */
1608 if (proxy_session && f.proxy_session_failed && p->cmd != QUIT_CMD)
1612 && strncmpic(smtp_cmd_buffer, US p->name, p->len) == 0
1613 && ( smtp_cmd_buffer[p->len-1] == ':' /* "mail from:" or "rcpt to:" */
1614 || smtp_cmd_buffer[p->len] == 0
1615 || smtp_cmd_buffer[p->len] == ' '
1618 if (smtp_inptr < smtp_inend && /* Outstanding input */
1619 p->cmd < sync_cmd_limit && /* Command should sync */
1620 check_sync && /* Local flag set */
1621 smtp_enforce_sync && /* Global flag set */
1622 sender_host_address != NULL && /* Not local input */
1623 !f.sender_host_notsocket) /* Really is a socket */
1626 /* The variables $smtp_command and $smtp_command_argument point into the
1627 unmodified input buffer. A copy of the latter is taken for actual
1628 processing, so that it can be chopped up into separate parts if necessary,
1629 for example, when processing a MAIL command options such as SIZE that can
1630 follow the sender address. */
1632 smtp_cmd_argument = smtp_cmd_buffer + p->len;
1633 while (isspace(*smtp_cmd_argument)) smtp_cmd_argument++;
1634 Ustrcpy(smtp_data_buffer, smtp_cmd_argument);
1635 smtp_cmd_data = smtp_data_buffer;
1637 /* Count non-mail commands from those hosts that are controlled in this
1638 way. The default is all hosts. We don't waste effort checking the list
1639 until we get a non-mail command, but then cache the result to save checking
1640 again. If there's a DEFER while checking the host, assume it's in the list.
1642 Note that one instance of RSET, EHLO/HELO, and STARTTLS is allowed at the
1643 start of each incoming message by fiddling with the value in the table. */
1645 if (!p->is_mail_cmd)
1647 if (count_nonmail == TRUE_UNSET) count_nonmail =
1648 verify_check_host(&smtp_accept_max_nonmail_hosts) != FAIL;
1649 if (count_nonmail && ++nonmail_command_count > smtp_accept_max_nonmail)
1650 return TOO_MANY_NONMAIL_CMD;
1653 /* If there is data for a command that does not expect it, generate the
1656 return (p->has_arg || *smtp_cmd_data == 0)? p->cmd : BADARG_CMD;
1660 #ifdef SUPPORT_PROXY
1661 /* Only allow QUIT command if Proxy Protocol parsing failed */
1662 if (proxy_session && f.proxy_session_failed)
1663 return PROXY_FAIL_IGNORE_CMD;
1666 /* Enforce synchronization for unknown commands */
1668 if ( smtp_inptr < smtp_inend /* Outstanding input */
1669 && check_sync /* Local flag set */
1670 && smtp_enforce_sync /* Global flag set */
1671 && sender_host_address /* Not local input */
1672 && !f.sender_host_notsocket) /* Really is a socket */
1680 /*************************************************
1681 * Forced closedown of call *
1682 *************************************************/
1684 /* This function is called from log.c when Exim is dying because of a serious
1685 disaster, and also from some other places. If an incoming non-batched SMTP
1686 channel is open, it swallows the rest of the incoming message if in the DATA
1687 phase, sends the reply string, and gives an error to all subsequent commands
1688 except QUIT. The existence of an SMTP call is detected by the non-NULLness of
1692 message SMTP reply string to send, excluding the code
1698 smtp_closedown(uschar *message)
1700 if (!smtp_in || smtp_batched_input) return;
1701 receive_swallow_smtp();
1702 smtp_printf("421 %s\r\n", FALSE, message);
1704 for (;;) switch(smtp_read_command(FALSE, GETC_BUFFER_UNLIMITED))
1710 f.smtp_in_quit = TRUE;
1711 smtp_printf("221 %s closing connection\r\n", FALSE, smtp_active_hostname);
1716 smtp_printf("250 Reset OK\r\n", FALSE);
1720 smtp_printf("421 %s\r\n", FALSE, message);
1728 /*************************************************
1729 * Set up connection info for logging *
1730 *************************************************/
1732 /* This function is called when logging information about an SMTP connection.
1733 It sets up appropriate source information, depending on the type of connection.
1734 If sender_fullhost is NULL, we are at a very early stage of the connection;
1735 just use the IP address.
1738 Returns: a string describing the connection
1742 smtp_get_connection_info(void)
1744 const uschar * hostname = sender_fullhost
1745 ? sender_fullhost : sender_host_address;
1748 return string_sprintf("SMTP connection from %s", hostname);
1750 if (f.sender_host_unknown || f.sender_host_notsocket)
1751 return string_sprintf("SMTP connection from %s", sender_ident);
1754 return string_sprintf("SMTP connection from %s (via inetd)", hostname);
1756 if (LOGGING(incoming_interface) && interface_address)
1757 return string_sprintf("SMTP connection from %s I=[%s]:%d", hostname,
1758 interface_address, interface_port);
1760 return string_sprintf("SMTP connection from %s", hostname);
1766 /* Append TLS-related information to a log line
1769 g String under construction: allocated string to extend, or NULL
1771 Returns: Allocated string or NULL
1774 s_tlslog(gstring * g)
1776 if (LOGGING(tls_cipher) && tls_in.cipher)
1778 g = string_append(g, 2, US" X=", tls_in.cipher);
1779 #ifndef DISABLE_TLS_RESUME
1780 if (LOGGING(tls_resumption) && tls_in.resumption & RESUME_USED)
1781 g = string_catn(g, US"*", 1);
1784 if (LOGGING(tls_certificate_verified) && tls_in.cipher)
1785 g = string_append(g, 2, US" CV=", tls_in.certificate_verified? "yes":"no");
1786 if (LOGGING(tls_peerdn) && tls_in.peerdn)
1787 g = string_append(g, 3, US" DN=\"", string_printing(tls_in.peerdn), US"\"");
1788 if (LOGGING(tls_sni) && tls_in.sni)
1789 g = string_append(g, 2, US" SNI=", string_printing2(tls_in.sni, SP_TAB|SP_SPACE));
1797 s_connhad_log(gstring * g)
1799 const uschar * sep = smtp_connection_had[SMTP_HBUFF_SIZE-1] != SCH_NONE
1800 ? US" C=..." : US" C=";
1802 for (int i = smtp_ch_index; i < SMTP_HBUFF_SIZE; i++)
1803 if (smtp_connection_had[i] != SCH_NONE)
1805 g = string_append(g, 2, sep, smtp_names[smtp_connection_had[i]]);
1808 for (int i = 0; i < smtp_ch_index; i++, sep = US",")
1809 g = string_append(g, 2, sep, smtp_names[smtp_connection_had[i]]);
1814 /*************************************************
1815 * Log lack of MAIL if so configured *
1816 *************************************************/
1818 /* This function is called when an SMTP session ends. If the log selector
1819 smtp_no_mail is set, write a log line giving some details of what has happened
1820 in the SMTP session.
1827 smtp_log_no_mail(void)
1832 if (smtp_mailcmd_count > 0 || !LOGGING(smtp_no_mail))
1835 if (sender_host_authenticated)
1837 g = string_append(g, 2, US" A=", sender_host_authenticated);
1838 if (authenticated_id) g = string_append(g, 2, US":", authenticated_id);
1845 g = s_connhad_log(g);
1847 if (!(s = string_from_gstring(g))) s = US"";
1849 log_write(0, LOG_MAIN, "no MAIL in %sSMTP connection from %s D=%s%s",
1850 f.tcp_in_fastopen ? f.tcp_in_fastopen_data ? US"TFO* " : US"TFO " : US"",
1851 host_and_ident(FALSE), string_timesince(&smtp_connection_start), s);
1855 /* Return list of recent smtp commands */
1860 gstring * list = NULL;
1863 for (int i = smtp_ch_index; i < SMTP_HBUFF_SIZE; i++)
1864 if (smtp_connection_had[i] != SCH_NONE)
1865 list = string_append_listele(list, ',', smtp_names[smtp_connection_had[i]]);
1867 for (int i = 0; i < smtp_ch_index; i++)
1868 list = string_append_listele(list, ',', smtp_names[smtp_connection_had[i]]);
1870 s = string_from_gstring(list);
1871 return s ? s : US"";
1877 /*************************************************
1878 * Check HELO line and set sender_helo_name *
1879 *************************************************/
1881 /* Check the format of a HELO line. The data for HELO/EHLO is supposed to be
1882 the domain name of the sending host, or an ip literal in square brackets. The
1883 argument is placed in sender_helo_name, which is in malloc store, because it
1884 must persist over multiple incoming messages. If helo_accept_junk is set, this
1885 host is permitted to send any old junk (needed for some broken hosts).
1886 Otherwise, helo_allow_chars can be used for rogue characters in general
1887 (typically people want to let in underscores).
1890 s the data portion of the line (already past any white space)
1892 Returns: TRUE or FALSE
1896 check_helo(uschar *s)
1899 uschar *end = s + Ustrlen(s);
1900 BOOL yield = fl.helo_accept_junk;
1902 /* Discard any previous helo name */
1904 sender_helo_name = NULL;
1906 /* Skip tests if junk is permitted. */
1910 /* Allow the new standard form for IPv6 address literals, namely,
1911 [IPv6:....], and because someone is bound to use it, allow an equivalent
1912 IPv4 form. Allow plain addresses as well. */
1919 if (strncmpic(s, US"[IPv6:", 6) == 0)
1920 yield = (string_is_ip_address(s+6, NULL) == 6);
1921 else if (strncmpic(s, US"[IPv4:", 6) == 0)
1922 yield = (string_is_ip_address(s+6, NULL) == 4);
1924 yield = (string_is_ip_address(s+1, NULL) != 0);
1929 /* Non-literals must be alpha, dot, hyphen, plus any non-valid chars
1930 that have been configured (usually underscore - sigh). */
1933 for (yield = TRUE; *s; s++)
1934 if (!isalnum(*s) && *s != '.' && *s != '-' &&
1935 Ustrchr(helo_allow_chars, *s) == NULL)
1941 /* Save argument if OK */
1943 if (yield) sender_helo_name = string_copy_perm(start, TRUE);
1951 /*************************************************
1952 * Extract SMTP command option *
1953 *************************************************/
1955 /* This function picks the next option setting off the end of smtp_cmd_data. It
1956 is called for MAIL FROM and RCPT TO commands, to pick off the optional ESMTP
1957 things that can appear there.
1960 name point this at the name
1961 value point this at the data string
1963 Returns: TRUE if found an option
1967 extract_option(uschar **name, uschar **value)
1970 uschar *v = smtp_cmd_data + Ustrlen(smtp_cmd_data) - 1;
1971 while (isspace(*v)) v--;
1973 while (v > smtp_cmd_data && *v != '=' && !isspace(*v))
1975 /* Take care to not stop at a space embedded in a quoted local-part */
1977 if ((*v == '"') && (v > smtp_cmd_data + 1))
1978 do v--; while (*v != '"' && v > smtp_cmd_data+1);
1985 while(isalpha(n[-1])) n--;
1986 /* RFC says SP, but TAB seen in wild and other major MTAs accept it */
1987 if (!isspace(n[-1])) return FALSE;
1993 if (v == smtp_cmd_data) return FALSE;
2005 /*************************************************
2006 * Reset for new message *
2007 *************************************************/
2009 /* This function is called whenever the SMTP session is reset from
2010 within either of the setup functions; also from the daemon loop.
2012 Argument: the stacking pool storage reset point
2017 smtp_reset(void *reset_point)
2019 recipients_list = NULL;
2020 rcpt_count = rcpt_defer_count = rcpt_fail_count =
2021 raw_recipients_count = recipients_count = recipients_list_max = 0;
2022 message_linecount = 0;
2024 message_body = message_body_end = NULL;
2025 acl_added_headers = NULL;
2026 acl_removed_headers = NULL;
2027 f.queue_only_policy = FALSE;
2028 rcpt_smtp_response = NULL;
2029 fl.rcpt_smtp_response_same = TRUE;
2030 fl.rcpt_in_progress = FALSE;
2031 f.deliver_freeze = FALSE; /* Can be set by ACL */
2032 freeze_tell = freeze_tell_config; /* Can be set by ACL */
2033 fake_response = OK; /* Can be set by ACL */
2034 #ifdef WITH_CONTENT_SCAN
2035 f.no_mbox_unspool = FALSE; /* Can be set by ACL */
2037 f.submission_mode = FALSE; /* Can be set by ACL */
2038 f.suppress_local_fixups = f.suppress_local_fixups_default; /* Can be set by ACL */
2039 f.active_local_from_check = local_from_check; /* Can be set by ACL */
2040 f.active_local_sender_retain = local_sender_retain; /* Can be set by ACL */
2041 sending_ip_address = NULL;
2042 return_path = sender_address = NULL;
2043 deliver_localpart_data = deliver_domain_data =
2044 recipient_data = sender_data = NULL; /* Can be set by ACL */
2045 recipient_verify_failure = NULL;
2046 deliver_localpart_parent = deliver_localpart_orig = NULL;
2047 deliver_domain_parent = deliver_domain_orig = NULL;
2048 callout_address = NULL;
2049 submission_name = NULL; /* Can be set by ACL */
2050 raw_sender = NULL; /* After SMTP rewrite, before qualifying */
2051 sender_address_unrewritten = NULL; /* Set only after verify rewrite */
2052 sender_verified_list = NULL; /* No senders verified */
2053 memset(sender_address_cache, 0, sizeof(sender_address_cache));
2054 memset(sender_domain_cache, 0, sizeof(sender_domain_cache));
2056 authenticated_sender = NULL;
2057 #ifdef EXPERIMENTAL_BRIGHTMAIL
2059 bmi_verdicts = NULL;
2061 dnslist_domain = dnslist_matched = NULL;
2063 spf_header_comment = spf_received = spf_result = spf_smtp_comment = NULL;
2064 spf_result_guessed = FALSE;
2066 #ifndef DISABLE_DKIM
2067 dkim_cur_signer = dkim_signers =
2068 dkim_signing_domain = dkim_signing_selector = dkim_signatures = NULL;
2069 dkim_cur_signer = dkim_signers = dkim_signing_domain = dkim_signing_selector = NULL;
2070 f.dkim_disable_verify = FALSE;
2071 dkim_collect_input = 0;
2072 dkim_verify_overall = dkim_verify_status = dkim_verify_reason = NULL;
2073 dkim_key_length = 0;
2075 #ifdef SUPPORT_DMARC
2076 f.dmarc_has_been_checked = f.dmarc_disable_verify = f.dmarc_enable_forensic = FALSE;
2077 dmarc_domain_policy = dmarc_status = dmarc_status_text =
2078 dmarc_used_domain = NULL;
2080 #ifdef EXPERIMENTAL_ARC
2081 arc_state = arc_state_reason = NULL;
2082 arc_received_instance = 0;
2086 deliver_host = deliver_host_address = NULL; /* Can be set by ACL */
2087 #ifndef DISABLE_PRDR
2088 prdr_requested = FALSE;
2091 message_smtputf8 = FALSE;
2093 body_linecount = body_zerocount = 0;
2095 sender_rate = sender_rate_limit = sender_rate_period = NULL;
2096 ratelimiters_mail = NULL; /* Updated by ratelimit ACL condition */
2097 /* Note that ratelimiters_conn persists across resets. */
2099 /* Reset message ACL variables */
2103 /* Warning log messages are saved in malloc store. They are saved to avoid
2104 repetition in the same message, but it seems right to repeat them for different
2107 while (acl_warn_logged)
2109 string_item *this = acl_warn_logged;
2110 acl_warn_logged = acl_warn_logged->next;
2115 store_reset(reset_point);
2118 return store_mark();
2125 /*************************************************
2126 * Initialize for incoming batched SMTP message *
2127 *************************************************/
2129 /* This function is called from smtp_setup_msg() in the case when
2130 smtp_batched_input is true. This happens when -bS is used to pass a whole batch
2131 of messages in one file with SMTP commands between them. All errors must be
2132 reported by sending a message, and only MAIL FROM, RCPT TO, and DATA are
2133 relevant. After an error on a sender, or an invalid recipient, the remainder
2134 of the message is skipped. The value of received_protocol is already set.
2137 Returns: > 0 message successfully started (reached DATA)
2138 = 0 QUIT read or end of file reached
2139 < 0 should not occur
2143 smtp_setup_batch_msg(void)
2146 rmark reset_point = store_mark();
2148 /* Save the line count at the start of each transaction - single commands
2149 like HELO and RSET count as whole transactions. */
2151 bsmtp_transaction_linecount = receive_linecount;
2153 if ((receive_feof)()) return 0; /* Treat EOF as QUIT */
2155 cancel_cutthrough_connection(TRUE, US"smtp_setup_batch_msg");
2156 reset_point = smtp_reset(reset_point); /* Reset for start of message */
2158 /* Deal with SMTP commands. This loop is exited by setting done to a POSITIVE
2159 value. The values are 2 larger than the required yield of the function. */
2164 uschar *recipient = NULL;
2165 int start, end, sender_domain, recipient_domain;
2167 switch(smtp_read_command(FALSE, GETC_BUFFER_UNLIMITED))
2169 /* The HELO/EHLO commands set sender_address_helo if they have
2170 valid data; otherwise they are ignored, except that they do
2171 a reset of the state. */
2176 check_helo(smtp_cmd_data);
2180 cancel_cutthrough_connection(TRUE, US"RSET received");
2181 reset_point = smtp_reset(reset_point);
2182 bsmtp_transaction_linecount = receive_linecount;
2186 /* The MAIL FROM command requires an address as an operand. All we
2187 do here is to parse it for syntactic correctness. The form "<>" is
2188 a special case which converts into an empty string. The start/end
2189 pointers in the original are not used further for this address, as
2190 it is the canonical extracted address which is all that is kept. */
2193 smtp_mailcmd_count++; /* Count for no-mail log */
2195 /* The function moan_smtp_batch() does not return. */
2196 moan_smtp_batch(smtp_cmd_buffer, "503 Sender already given");
2198 if (smtp_cmd_data[0] == 0)
2199 /* The function moan_smtp_batch() does not return. */
2200 moan_smtp_batch(smtp_cmd_buffer, "501 MAIL FROM must have an address operand");
2202 /* Reset to start of message */
2204 cancel_cutthrough_connection(TRUE, US"MAIL received");
2205 reset_point = smtp_reset(reset_point);
2207 /* Apply SMTP rewrite */
2209 raw_sender = ((rewrite_existflags & rewrite_smtp) != 0)?
2210 rewrite_one(smtp_cmd_data, rewrite_smtp|rewrite_smtp_sender, NULL, FALSE,
2211 US"", global_rewrite_rules) : smtp_cmd_data;
2213 /* Extract the address; the TRUE flag allows <> as valid */
2216 parse_extract_address(raw_sender, &errmess, &start, &end, &sender_domain,
2220 /* The function moan_smtp_batch() does not return. */
2221 moan_smtp_batch(smtp_cmd_buffer, "501 %s", errmess);
2223 sender_address = string_copy(raw_sender);
2225 /* Qualify unqualified sender addresses if permitted to do so. */
2228 && sender_address[0] != 0 && sender_address[0] != '@')
2229 if (f.allow_unqualified_sender)
2231 sender_address = rewrite_address_qualify(sender_address, FALSE);
2232 DEBUG(D_receive) debug_printf("unqualified address %s accepted "
2233 "and rewritten\n", raw_sender);
2235 /* The function moan_smtp_batch() does not return. */
2237 moan_smtp_batch(smtp_cmd_buffer, "501 sender address must contain "
2242 /* The RCPT TO command requires an address as an operand. All we do
2243 here is to parse it for syntactic correctness. There may be any number
2244 of RCPT TO commands, specifying multiple senders. We build them all into
2245 a data structure that is in argc/argv format. The start/end values
2246 given by parse_extract_address are not used, as we keep only the
2247 extracted address. */
2250 if (!sender_address)
2251 /* The function moan_smtp_batch() does not return. */
2252 moan_smtp_batch(smtp_cmd_buffer, "503 No sender yet given");
2254 if (smtp_cmd_data[0] == 0)
2255 /* The function moan_smtp_batch() does not return. */
2256 moan_smtp_batch(smtp_cmd_buffer,
2257 "501 RCPT TO must have an address operand");
2259 /* Check maximum number allowed */
2261 if (recipients_max > 0 && recipients_count + 1 > recipients_max)
2262 /* The function moan_smtp_batch() does not return. */
2263 moan_smtp_batch(smtp_cmd_buffer, "%s too many recipients",
2264 recipients_max_reject? "552": "452");
2266 /* Apply SMTP rewrite, then extract address. Don't allow "<>" as a
2267 recipient address */
2269 recipient = rewrite_existflags & rewrite_smtp
2270 ? rewrite_one(smtp_cmd_data, rewrite_smtp, NULL, FALSE, US"",
2271 global_rewrite_rules)
2274 recipient = parse_extract_address(recipient, &errmess, &start, &end,
2275 &recipient_domain, FALSE);
2278 /* The function moan_smtp_batch() does not return. */
2279 moan_smtp_batch(smtp_cmd_buffer, "501 %s", errmess);
2281 /* If the recipient address is unqualified, qualify it if permitted. Then
2282 add it to the list of recipients. */
2284 if (!recipient_domain)
2285 if (f.allow_unqualified_recipient)
2287 DEBUG(D_receive) debug_printf("unqualified address %s accepted\n",
2289 recipient = rewrite_address_qualify(recipient, TRUE);
2291 /* The function moan_smtp_batch() does not return. */
2293 moan_smtp_batch(smtp_cmd_buffer,
2294 "501 recipient address must contain a domain");
2296 receive_add_recipient(recipient, -1);
2300 /* The DATA command is legal only if it follows successful MAIL FROM
2301 and RCPT TO commands. This function is complete when a valid DATA
2302 command is encountered. */
2305 if (!sender_address || recipients_count <= 0)
2306 /* The function moan_smtp_batch() does not return. */
2307 if (!sender_address)
2308 moan_smtp_batch(smtp_cmd_buffer,
2309 "503 MAIL FROM:<sender> command must precede DATA");
2311 moan_smtp_batch(smtp_cmd_buffer,
2312 "503 RCPT TO:<recipient> must precede DATA");
2315 done = 3; /* DATA successfully achieved */
2316 message_ended = END_NOTENDED; /* Indicate in middle of message */
2321 /* The VRFY, EXPN, HELP, ETRN, and NOOP commands are ignored. */
2328 bsmtp_transaction_linecount = receive_linecount;
2333 f.smtp_in_quit = TRUE;
2340 /* The function moan_smtp_batch() does not return. */
2341 moan_smtp_batch(smtp_cmd_buffer, "501 Unexpected argument data");
2346 /* The function moan_smtp_batch() does not return. */
2347 moan_smtp_batch(smtp_cmd_buffer, "501 Unexpected NULL in SMTP command");
2352 /* The function moan_smtp_batch() does not return. */
2353 moan_smtp_batch(smtp_cmd_buffer, "500 Command unrecognized");
2358 return done - 2; /* Convert yield values */
2366 smtp_log_tls_fail(uschar * errstr)
2368 uschar * conn_info = smtp_get_connection_info();
2370 if (Ustrncmp(conn_info, US"SMTP ", 5) == 0) conn_info += 5;
2371 /* I'd like to get separated H= here, but too hard for now */
2373 log_write(0, LOG_MAIN, "TLS error on %s %s", conn_info, errstr);
2387 socklen_t len = sizeof(is_fastopen);
2389 /* The tinfo TCPOPT_FAST_OPEN bit seems unreliable, and we don't see state
2390 TCP_SYN_RCV (as of 12.1) so no idea about data-use. */
2392 if (getsockopt(fileno(smtp_out), IPPROTO_TCP, TCP_FASTOPEN, &is_fastopen, &len) == 0)
2397 debug_printf("TFO mode connection (TCP_FASTOPEN getsockopt)\n");
2398 f.tcp_in_fastopen = TRUE;
2401 else DEBUG(D_receive)
2402 debug_printf("TCP_INFO getsockopt: %s\n", strerror(errno));
2404 # elif defined(TCP_INFO)
2405 struct tcp_info tinfo;
2406 socklen_t len = sizeof(tinfo);
2408 if (getsockopt(fileno(smtp_out), IPPROTO_TCP, TCP_INFO, &tinfo, &len) == 0)
2409 # ifdef TCPI_OPT_SYN_DATA /* FreeBSD 11,12 do not seem to have this yet */
2410 if (tinfo.tcpi_options & TCPI_OPT_SYN_DATA)
2413 debug_printf("TFO mode connection (ACKd data-on-SYN)\n");
2414 f.tcp_in_fastopen_data = f.tcp_in_fastopen = TRUE;
2418 if (tinfo.tcpi_state == TCP_SYN_RECV) /* Not seen on FreeBSD 12.1 */
2421 debug_printf("TFO mode connection (state TCP_SYN_RECV)\n");
2422 f.tcp_in_fastopen = TRUE;
2424 else DEBUG(D_receive)
2425 debug_printf("TCP_INFO getsockopt: %s\n", strerror(errno));
2431 /*************************************************
2432 * Start an SMTP session *
2433 *************************************************/
2435 /* This function is called at the start of an SMTP session. Thereafter,
2436 smtp_setup_msg() is called to initiate each separate message. This
2437 function does host-specific testing, and outputs the banner line.
2440 Returns: FALSE if the session can not continue; something has
2441 gone wrong, or the connection to the host is blocked
2445 smtp_start_session(void)
2448 uschar *user_msg, *log_msg;
2453 gettimeofday(&smtp_connection_start, NULL);
2454 for (smtp_ch_index = 0; smtp_ch_index < SMTP_HBUFF_SIZE; smtp_ch_index++)
2455 smtp_connection_had[smtp_ch_index] = SCH_NONE;
2458 /* Default values for certain variables */
2460 fl.helo_seen = fl.esmtp = fl.helo_accept_junk = FALSE;
2461 smtp_mailcmd_count = 0;
2462 count_nonmail = TRUE_UNSET;
2463 synprot_error_count = unknown_command_count = nonmail_command_count = 0;
2464 smtp_delay_mail = smtp_rlm_base;
2465 fl.auth_advertised = FALSE;
2466 f.smtp_in_pipelining_advertised = f.smtp_in_pipelining_used = FALSE;
2467 f.pipelining_enable = TRUE;
2468 sync_cmd_limit = NON_SYNC_CMD_NON_PIPELINING;
2469 fl.smtp_exit_function_called = FALSE; /* For avoiding loop in not-quit exit */
2471 /* If receiving by -bs from a trusted user, or testing with -bh, we allow
2472 authentication settings from -oMaa to remain in force. */
2474 if (!host_checking && !f.sender_host_notsocket)
2475 sender_host_auth_pubname = sender_host_authenticated = NULL;
2476 authenticated_by = NULL;
2479 tls_in.ver = tls_in.cipher = tls_in.peerdn = NULL;
2480 tls_in.ourcert = tls_in.peercert = NULL;
2482 tls_in.ocsp = OCSP_NOT_REQ;
2483 fl.tls_advertised = FALSE;
2485 fl.dsn_advertised = FALSE;
2487 fl.smtputf8_advertised = FALSE;
2490 /* Reset ACL connection variables */
2494 /* Allow for trailing 0 in the command and data buffers. Tainted. */
2496 smtp_cmd_buffer = store_get_perm(2*SMTP_CMD_BUFFER_SIZE + 2, TRUE);
2498 smtp_cmd_buffer[0] = 0;
2499 smtp_data_buffer = smtp_cmd_buffer + SMTP_CMD_BUFFER_SIZE + 1;
2501 /* For batched input, the protocol setting can be overridden from the
2502 command line by a trusted caller. */
2504 if (smtp_batched_input)
2506 if (!received_protocol) received_protocol = US"local-bsmtp";
2509 /* For non-batched SMTP input, the protocol setting is forced here. It will be
2510 reset later if any of EHLO/AUTH/STARTTLS are received. */
2514 (sender_host_address ? protocols : protocols_local) [pnormal];
2516 /* Set up the buffer for inputting using direct read() calls, and arrange to
2517 call the local functions instead of the standard C ones. Place a NUL at the
2518 end of the buffer to safety-stop C-string reads from it. */
2520 if (!(smtp_inbuffer = US malloc(IN_BUFFER_SIZE)))
2521 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "malloc() failed for SMTP input buffer");
2522 smtp_inbuffer[IN_BUFFER_SIZE-1] = '\0';
2524 receive_getc = smtp_getc;
2525 receive_getbuf = smtp_getbuf;
2526 receive_get_cache = smtp_get_cache;
2527 receive_ungetc = smtp_ungetc;
2528 receive_feof = smtp_feof;
2529 receive_ferror = smtp_ferror;
2530 receive_smtp_buffered = smtp_buffered;
2531 smtp_inptr = smtp_inend = smtp_inbuffer;
2532 smtp_had_eof = smtp_had_error = 0;
2534 /* Set up the message size limit; this may be host-specific */
2536 thismessage_size_limit = expand_string_integer(message_size_limit, TRUE);
2537 if (expand_string_message)
2539 if (thismessage_size_limit == -1)
2540 log_write(0, LOG_MAIN|LOG_PANIC, "unable to expand message_size_limit: "
2541 "%s", expand_string_message);
2543 log_write(0, LOG_MAIN|LOG_PANIC, "invalid message_size_limit: "
2544 "%s", expand_string_message);
2545 smtp_closedown(US"Temporary local problem - please try later");
2549 /* When a message is input locally via the -bs or -bS options, sender_host_
2550 unknown is set unless -oMa was used to force an IP address, in which case it
2551 is checked like a real remote connection. When -bs is used from inetd, this
2552 flag is not set, causing the sending host to be checked. The code that deals
2553 with IP source routing (if configured) is never required for -bs or -bS and
2554 the flag sender_host_notsocket is used to suppress it.
2556 If smtp_accept_max and smtp_accept_reserve are set, keep some connections in
2557 reserve for certain hosts and/or networks. */
2559 if (!f.sender_host_unknown)
2562 BOOL reserved_host = FALSE;
2564 /* Look up IP options (source routing info) on the socket if this is not an
2565 -oMa "host", and if any are found, log them and drop the connection.
2567 Linux (and others now, see below) is different to everyone else, so there
2568 has to be some conditional compilation here. Versions of Linux before 2.1.15
2569 used a structure whose name was "options". Somebody finally realized that
2570 this name was silly, and it got changed to "ip_options". I use the
2571 newer name here, but there is a fudge in the script that sets up os.h
2572 to define a macro in older Linux systems.
2574 Sigh. Linux is a fast-moving target. Another generation of Linux uses
2575 glibc 2, which has chosen ip_opts for the structure name. This is now
2576 really a glibc thing rather than a Linux thing, so the condition name
2577 has been changed to reflect this. It is relevant also to GNU/Hurd.
2579 Mac OS 10.x (Darwin) is like the later glibc versions, but without the
2580 setting of the __GLIBC__ macro, so we can't detect it automatically. There's
2581 a special macro defined in the os.h file.
2583 Some DGUX versions on older hardware appear not to support IP options at
2584 all, so there is now a general macro which can be set to cut out this
2587 How to do this properly in IPv6 is not yet known. */
2589 #if !HAVE_IPV6 && !defined(NO_IP_OPTIONS)
2591 #ifdef GLIBC_IP_OPTIONS
2592 #if (!defined __GLIBC__) || (__GLIBC__ < 2)
2597 #elif defined DARWIN_IP_OPTIONS
2603 if (!host_checking && !f.sender_host_notsocket)
2606 EXIM_SOCKLEN_T optlen = sizeof(struct ip_options) + MAX_IPOPTLEN;
2607 struct ip_options *ipopt = store_get(optlen, FALSE);
2609 struct ip_opts ipoptblock;
2610 struct ip_opts *ipopt = &ipoptblock;
2611 EXIM_SOCKLEN_T optlen = sizeof(ipoptblock);
2613 struct ipoption ipoptblock;
2614 struct ipoption *ipopt = &ipoptblock;
2615 EXIM_SOCKLEN_T optlen = sizeof(ipoptblock);
2618 /* Occasional genuine failures of getsockopt() have been seen - for
2619 example, "reset by peer". Therefore, just log and give up on this
2620 call, unless the error is ENOPROTOOPT. This error is given by systems
2621 that have the interfaces but not the mechanism - e.g. GNU/Hurd at the time
2622 of writing. So for that error, carry on - we just can't do an IP options
2625 DEBUG(D_receive) debug_printf("checking for IP options\n");
2627 if (getsockopt(fileno(smtp_out), IPPROTO_IP, IP_OPTIONS, US (ipopt),
2630 if (errno != ENOPROTOOPT)
2632 log_write(0, LOG_MAIN, "getsockopt() failed from %s: %s",
2633 host_and_ident(FALSE), strerror(errno));
2634 smtp_printf("451 SMTP service not available\r\n", FALSE);
2639 /* Deal with any IP options that are set. On the systems I have looked at,
2640 the value of MAX_IPOPTLEN has been 40, meaning that there should never be
2641 more logging data than will fit in big_buffer. Nevertheless, after somebody
2642 questioned this code, I've added in some paranoid checking. */
2644 else if (optlen > 0)
2646 uschar *p = big_buffer;
2647 uschar *pend = big_buffer + big_buffer_size;
2650 struct in_addr addr;
2653 uschar *optstart = US (ipopt->__data);
2655 uschar *optstart = US (ipopt->ip_opts);
2657 uschar *optstart = US (ipopt->ipopt_list);
2660 DEBUG(D_receive) debug_printf("IP options exist\n");
2662 Ustrcpy(p, "IP options on incoming call:");
2665 for (uschar * opt = optstart; opt && opt < US (ipopt) + optlen; )
2678 if (!string_format(p, pend-p, " %s [@%s",
2679 (*opt == IPOPT_SSRR)? "SSRR" : "LSRR",
2681 inet_ntoa(*((struct in_addr *)(&(ipopt->faddr))))))
2683 inet_ntoa(ipopt->ip_dst)))
2685 inet_ntoa(ipopt->ipopt_dst)))
2693 optcount = (opt[1] - 3) / sizeof(struct in_addr);
2695 while (optcount-- > 0)
2697 memcpy(&addr, adptr, sizeof(addr));
2698 if (!string_format(p, pend - p - 1, "%s%s",
2699 (optcount == 0)? ":" : "@", inet_ntoa(addr)))
2705 adptr += sizeof(struct in_addr);
2713 if (pend - p < 4 + 3*opt[1]) { opt = NULL; break; }
2716 for (int i = 0; i < opt[1]; i++)
2717 p += sprintf(CS p, "%2.2x ", opt[i]);
2725 log_write(0, LOG_MAIN, "%s", big_buffer);
2727 /* Refuse any call with IP options. This is what tcpwrappers 7.5 does. */
2729 log_write(0, LOG_MAIN|LOG_REJECT,
2730 "connection from %s refused (IP options)", host_and_ident(FALSE));
2732 smtp_printf("554 SMTP service not available\r\n", FALSE);
2736 /* Length of options = 0 => there are no options */
2738 else DEBUG(D_receive) debug_printf("no IP options found\n");
2740 #endif /* HAVE_IPV6 && !defined(NO_IP_OPTIONS) */
2742 /* Set keep-alive in socket options. The option is on by default. This
2743 setting is an attempt to get rid of some hanging connections that stick in
2744 read() when the remote end (usually a dialup) goes away. */
2746 if (smtp_accept_keepalive && !f.sender_host_notsocket)
2747 ip_keepalive(fileno(smtp_out), sender_host_address, FALSE);
2749 /* If the current host matches host_lookup, set the name by doing a
2750 reverse lookup. On failure, sender_host_name will be NULL and
2751 host_lookup_failed will be TRUE. This may or may not be serious - optional
2754 if (verify_check_host(&host_lookup) == OK)
2756 (void)host_name_lookup();
2757 host_build_sender_fullhost();
2760 /* Delay this until we have the full name, if it is looked up. */
2762 set_process_info("handling incoming connection from %s",
2763 host_and_ident(FALSE));
2765 /* Expand smtp_receive_timeout, if needed */
2767 if (smtp_receive_timeout_s)
2770 if ( !(exp = expand_string(smtp_receive_timeout_s))
2772 || (smtp_receive_timeout = readconf_readtime(exp, 0, FALSE)) < 0
2774 log_write(0, LOG_MAIN|LOG_PANIC,
2775 "bad value for smtp_receive_timeout: '%s'", exp ? exp : US"");
2778 /* Test for explicit connection rejection */
2780 if (verify_check_host(&host_reject_connection) == OK)
2782 log_write(L_connection_reject, LOG_MAIN|LOG_REJECT, "refused connection "
2783 "from %s (host_reject_connection)", host_and_ident(FALSE));
2784 smtp_printf("554 SMTP service not available\r\n", FALSE);
2788 /* Test with TCP Wrappers if so configured. There is a problem in that
2789 hosts_ctl() returns 0 (deny) under a number of system failure circumstances,
2790 such as disks dying. In these cases, it is desirable to reject with a 4xx
2791 error instead of a 5xx error. There isn't a "right" way to detect such
2792 problems. The following kludge is used: errno is zeroed before calling
2793 hosts_ctl(). If the result is "reject", a 5xx error is given only if the
2794 value of errno is 0 or ENOENT (which happens if /etc/hosts.{allow,deny} does
2797 #ifdef USE_TCP_WRAPPERS
2799 if (!(tcp_wrappers_name = expand_string(tcp_wrappers_daemon_name)))
2800 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "Expansion of \"%s\" "
2801 "(tcp_wrappers_name) failed: %s", string_printing(tcp_wrappers_name),
2802 expand_string_message);
2804 if (!hosts_ctl(tcp_wrappers_name,
2805 sender_host_name ? CS sender_host_name : STRING_UNKNOWN,
2806 sender_host_address ? CS sender_host_address : STRING_UNKNOWN,
2807 sender_ident ? CS sender_ident : STRING_UNKNOWN))
2809 if (errno == 0 || errno == ENOENT)
2811 HDEBUG(D_receive) debug_printf("tcp wrappers rejection\n");
2812 log_write(L_connection_reject,
2813 LOG_MAIN|LOG_REJECT, "refused connection from %s "
2814 "(tcp wrappers)", host_and_ident(FALSE));
2815 smtp_printf("554 SMTP service not available\r\n", FALSE);
2819 int save_errno = errno;
2820 HDEBUG(D_receive) debug_printf("tcp wrappers rejected with unexpected "
2821 "errno value %d\n", save_errno);
2822 log_write(L_connection_reject,
2823 LOG_MAIN|LOG_REJECT, "temporarily refused connection from %s "
2824 "(tcp wrappers errno=%d)", host_and_ident(FALSE), save_errno);
2825 smtp_printf("451 Temporary local problem - please try later\r\n", FALSE);
2831 /* Check for reserved slots. The value of smtp_accept_count has already been
2832 incremented to include this process. */
2834 if (smtp_accept_max > 0 &&
2835 smtp_accept_count > smtp_accept_max - smtp_accept_reserve)
2837 if ((rc = verify_check_host(&smtp_reserve_hosts)) != OK)
2839 log_write(L_connection_reject,
2840 LOG_MAIN, "temporarily refused connection from %s: not in "
2841 "reserve list: connected=%d max=%d reserve=%d%s",
2842 host_and_ident(FALSE), smtp_accept_count - 1, smtp_accept_max,
2843 smtp_accept_reserve, (rc == DEFER)? " (lookup deferred)" : "");
2844 smtp_printf("421 %s: Too many concurrent SMTP connections; "
2845 "please try again later\r\n", FALSE, smtp_active_hostname);
2848 reserved_host = TRUE;
2851 /* If a load level above which only messages from reserved hosts are
2852 accepted is set, check the load. For incoming calls via the daemon, the
2853 check is done in the superior process if there are no reserved hosts, to
2854 save a fork. In all cases, the load average will already be available
2855 in a global variable at this point. */
2857 if (smtp_load_reserve >= 0 &&
2858 load_average > smtp_load_reserve &&
2860 verify_check_host(&smtp_reserve_hosts) != OK)
2862 log_write(L_connection_reject,
2863 LOG_MAIN, "temporarily refused connection from %s: not in "
2864 "reserve list and load average = %.2f", host_and_ident(FALSE),
2865 (double)load_average/1000.0);
2866 smtp_printf("421 %s: Too much load; please try again later\r\n", FALSE,
2867 smtp_active_hostname);
2871 /* Determine whether unqualified senders or recipients are permitted
2872 for this host. Unfortunately, we have to do this every time, in order to
2873 set the flags so that they can be inspected when considering qualifying
2874 addresses in the headers. For a site that permits no qualification, this
2875 won't take long, however. */
2877 f.allow_unqualified_sender =
2878 verify_check_host(&sender_unqualified_hosts) == OK;
2880 f.allow_unqualified_recipient =
2881 verify_check_host(&recipient_unqualified_hosts) == OK;
2883 /* Determine whether HELO/EHLO is required for this host. The requirement
2884 can be hard or soft. */
2886 fl.helo_required = verify_check_host(&helo_verify_hosts) == OK;
2887 if (!fl.helo_required)
2888 fl.helo_verify = verify_check_host(&helo_try_verify_hosts) == OK;
2890 /* Determine whether this hosts is permitted to send syntactic junk
2891 after a HELO or EHLO command. */
2893 fl.helo_accept_junk = verify_check_host(&helo_accept_junk_hosts) == OK;
2896 /* For batch SMTP input we are now done. */
2898 if (smtp_batched_input) return TRUE;
2900 /* If valid Proxy Protocol source is connecting, set up session.
2901 Failure will not allow any SMTP function other than QUIT. */
2903 #ifdef SUPPORT_PROXY
2904 proxy_session = FALSE;
2905 f.proxy_session_failed = FALSE;
2906 if (check_proxy_protocol_host())
2907 setup_proxy_protocol_host();
2910 /* Start up TLS if tls_on_connect is set. This is for supporting the legacy
2911 smtps port for use with older style SSL MTAs. */
2914 if (tls_in.on_connect)
2916 if (tls_server_start(&user_msg) != OK)
2917 return smtp_log_tls_fail(user_msg);
2918 cmd_list[CMD_LIST_TLS_AUTH].is_mail_cmd = TRUE;
2922 /* Run the connect ACL if it exists */
2925 if (acl_smtp_connect)
2928 if ((rc = acl_check(ACL_WHERE_CONNECT, NULL, acl_smtp_connect, &user_msg,
2931 (void) smtp_handle_acl_fail(ACL_WHERE_CONNECT, rc, user_msg, log_msg);
2936 /* Output the initial message for a two-way SMTP connection. It may contain
2937 newlines, which then cause a multi-line response to be given. */
2939 code = US"220"; /* Default status code */
2940 esc = US""; /* Default extended status code */
2941 esclen = 0; /* Length of esc */
2945 if (!(s = expand_string(smtp_banner)))
2946 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "Expansion of \"%s\" (smtp_banner) "
2947 "failed: %s", smtp_banner, expand_string_message);
2953 smtp_message_code(&code, &codelen, &s, NULL, TRUE);
2957 esclen = codelen - 4;
2961 /* Remove any terminating newlines; might as well remove trailing space too */
2964 while (p > s && isspace(p[-1])) p--;
2967 /* It seems that CC:Mail is braindead, and assumes that the greeting message
2968 is all contained in a single IP packet. The original code wrote out the
2969 greeting using several calls to fprint/fputc, and on busy servers this could
2970 cause it to be split over more than one packet - which caused CC:Mail to fall
2971 over when it got the second part of the greeting after sending its first
2972 command. Sigh. To try to avoid this, build the complete greeting message
2973 first, and output it in one fell swoop. This gives a better chance of it
2974 ending up as a single packet. */
2976 ss = string_get(256);
2979 do /* At least once, in case we have an empty string */
2982 uschar *linebreak = Ustrchr(p, '\n');
2983 ss = string_catn(ss, code, 3);
2987 ss = string_catn(ss, US" ", 1);
2991 len = linebreak - p;
2992 ss = string_catn(ss, US"-", 1);
2994 ss = string_catn(ss, esc, esclen);
2995 ss = string_catn(ss, p, len);
2996 ss = string_catn(ss, US"\r\n", 2);
3002 /* Before we write the banner, check that there is no input pending, unless
3003 this synchronisation check is disabled. */
3005 #ifndef DISABLE_PIPE_CONNECT
3006 fl.pipe_connect_acceptable =
3007 sender_host_address && verify_check_host(&pipe_connect_advertise_hosts) == OK;
3010 if (fl.pipe_connect_acceptable)
3011 f.smtp_in_early_pipe_used = TRUE;
3017 unsigned n = smtp_inend - smtp_inptr;
3018 if (n > 128) n = 128;
3020 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP protocol "
3021 "synchronization error (input sent without waiting for greeting): "
3022 "rejected connection from %s input=\"%s\"", host_and_ident(TRUE),
3023 string_printing(string_copyn(smtp_inptr, n)));
3024 smtp_printf("554 SMTP synchronization error\r\n", FALSE);
3028 /* Now output the banner */
3029 /*XXX the ehlo-resp code does its own tls/nontls bit. Maybe subroutine that? */
3032 #ifndef DISABLE_PIPE_CONNECT
3033 fl.pipe_connect_acceptable && pipeline_connect_sends(),
3037 string_from_gstring(ss));
3039 /* Attempt to see if we sent the banner before the last ACK of the 3-way
3040 handshake arrived. If so we must have managed a TFO. */
3043 if (sender_host_address && !f.sender_host_notsocket) tfo_in_check();
3053 /*************************************************
3054 * Handle SMTP syntax and protocol errors *
3055 *************************************************/
3057 /* Write to the log for SMTP syntax errors in incoming commands, if configured
3058 to do so. Then transmit the error response. The return value depends on the
3059 number of syntax and protocol errors in this SMTP session.
3062 type error type, given as a log flag bit
3063 code response code; <= 0 means don't send a response
3064 data data to reflect in the response (can be NULL)
3065 errmess the error message
3067 Returns: -1 limit of syntax/protocol errors NOT exceeded
3068 +1 limit of syntax/protocol errors IS exceeded
3070 These values fit in with the values of the "done" variable in the main
3071 processing loop in smtp_setup_msg(). */
3074 synprot_error(int type, int code, uschar *data, uschar *errmess)
3078 log_write(type, LOG_MAIN, "SMTP %s error in \"%s\" %s %s",
3079 type == L_smtp_syntax_error ? "syntax" : "protocol",
3080 string_printing(smtp_cmd_buffer), host_and_ident(TRUE), errmess);
3082 if (++synprot_error_count > smtp_max_synprot_errors)
3085 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
3086 "syntax or protocol errors (last command was \"%s\", %s)",
3087 host_and_ident(FALSE), string_printing(smtp_cmd_buffer),
3088 string_from_gstring(s_connhad_log(NULL))
3094 smtp_printf("%d%c%s%s%s\r\n", FALSE, code, yield == 1 ? '-' : ' ',
3095 data ? data : US"", data ? US": " : US"", errmess);
3097 smtp_printf("%d Too many syntax or protocol errors\r\n", FALSE, code);
3106 /*************************************************
3107 * Send SMTP response, possibly multiline *
3108 *************************************************/
3110 /* There are, it seems, broken clients out there that cannot handle multiline
3111 responses. If no_multiline_responses is TRUE (it can be set from an ACL), we
3112 output nothing for non-final calls, and only the first line for anything else.
3115 code SMTP code, may involve extended status codes
3116 codelen length of smtp code; if > 4 there's an ESC
3117 final FALSE if the last line isn't the final line
3118 msg message text, possibly containing newlines
3124 smtp_respond(uschar* code, int codelen, BOOL final, uschar *msg)
3129 if (!final && f.no_multiline_responses) return;
3134 esclen = codelen - 4;
3137 /* If this is the first output for a (non-batch) RCPT command, see if all RCPTs
3138 have had the same. Note: this code is also present in smtp_printf(). It would
3139 be tidier to have it only in one place, but when it was added, it was easier to
3140 do it that way, so as not to have to mess with the code for the RCPT command,
3141 which sometimes uses smtp_printf() and sometimes smtp_respond(). */
3143 if (fl.rcpt_in_progress)
3145 if (rcpt_smtp_response == NULL)
3146 rcpt_smtp_response = string_copy(msg);
3147 else if (fl.rcpt_smtp_response_same &&
3148 Ustrcmp(rcpt_smtp_response, msg) != 0)
3149 fl.rcpt_smtp_response_same = FALSE;
3150 fl.rcpt_in_progress = FALSE;
3153 /* Now output the message, splitting it up into multiple lines if necessary.
3154 We only handle pipelining these responses as far as nonfinal/final groups,
3155 not the whole MAIL/RCPT/DATA response set. */
3159 uschar *nl = Ustrchr(msg, '\n');
3162 smtp_printf("%.3s%c%.*s%s\r\n", !final, code, final ? ' ':'-', esclen, esc, msg);
3165 else if (nl[1] == 0 || f.no_multiline_responses)
3167 smtp_printf("%.3s%c%.*s%.*s\r\n", !final, code, final ? ' ':'-', esclen, esc,
3168 (int)(nl - msg), msg);
3173 smtp_printf("%.3s-%.*s%.*s\r\n", TRUE, code, esclen, esc, (int)(nl - msg), msg);
3175 Uskip_whitespace(&msg);
3183 /*************************************************
3184 * Parse user SMTP message *
3185 *************************************************/
3187 /* This function allows for user messages overriding the response code details
3188 by providing a suitable response code string at the start of the message
3189 user_msg. Check the message for starting with a response code and optionally an
3190 extended status code. If found, check that the first digit is valid, and if so,
3191 change the code pointer and length to use the replacement. An invalid code
3192 causes a panic log; in this case, if the log messages is the same as the user
3193 message, we must also adjust the value of the log message to show the code that
3194 is actually going to be used (the original one).
3196 This function is global because it is called from receive.c as well as within
3199 Note that the code length returned includes the terminating whitespace
3200 character, which is always included in the regex match.
3203 code SMTP code, may involve extended status codes
3204 codelen length of smtp code; if > 4 there's an ESC
3206 log_msg optional log message, to be adjusted with the new SMTP code
3207 check_valid if true, verify the response code
3213 smtp_message_code(uschar **code, int *codelen, uschar **msg, uschar **log_msg,
3219 if (!msg || !*msg) return;
3221 if ((n = pcre_exec(regex_smtp_code, NULL, CS *msg, Ustrlen(*msg), 0,
3222 PCRE_EOPT, ovector, sizeof(ovector)/sizeof(int))) < 0) return;
3224 if (check_valid && (*msg)[0] != (*code)[0])
3226 log_write(0, LOG_MAIN|LOG_PANIC, "configured error code starts with "
3227 "incorrect digit (expected %c) in \"%s\"", (*code)[0], *msg);
3228 if (log_msg != NULL && *log_msg == *msg)
3229 *log_msg = string_sprintf("%s %s", *code, *log_msg + ovector[1]);
3234 *codelen = ovector[1]; /* Includes final space */
3236 *msg += ovector[1]; /* Chop the code off the message */
3243 /*************************************************
3244 * Handle an ACL failure *
3245 *************************************************/
3247 /* This function is called when acl_check() fails. As well as calls from within
3248 this module, it is called from receive.c for an ACL after DATA. It sorts out
3249 logging the incident, and sends the error response. A message containing
3250 newlines is turned into a multiline SMTP response, but for logging, only the
3253 There's a table of default permanent failure response codes to use in
3254 globals.c, along with the table of names. VFRY is special. Despite RFC1123 it
3255 defaults disabled in Exim. However, discussion in connection with RFC 821bis
3256 (aka RFC 2821) has concluded that the response should be 252 in the disabled
3257 state, because there are broken clients that try VRFY before RCPT. A 5xx
3258 response should be given only when the address is positively known to be
3259 undeliverable. Sigh. We return 252 if there is no VRFY ACL or it provides
3260 no explicit code, but if there is one we let it know best.
3261 Also, for ETRN, 458 is given on refusal, and for AUTH, 503.
3263 From Exim 4.63, it is possible to override the response code details by
3264 providing a suitable response code string at the start of the message provided
3265 in user_msg. The code's first digit is checked for validity.
3268 where where the ACL was called from
3270 user_msg a message that can be included in an SMTP response
3271 log_msg a message for logging
3273 Returns: 0 in most cases
3274 2 if the failure code was FAIL_DROP, in which case the
3275 SMTP connection should be dropped (this value fits with the
3276 "done" variable in smtp_setup_msg() below)
3280 smtp_handle_acl_fail(int where, int rc, uschar *user_msg, uschar *log_msg)
3282 BOOL drop = rc == FAIL_DROP;
3286 uschar *sender_info = US"";
3289 if (drop) rc = FAIL;
3291 /* Set the default SMTP code, and allow a user message to change it. */
3293 smtp_code = rc == FAIL ? acl_wherecodes[where] : US"451";
3294 smtp_message_code(&smtp_code, &codelen, &user_msg, &log_msg,
3295 where != ACL_WHERE_VRFY);
3297 /* We used to have sender_address here; however, there was a bug that was not
3298 updating sender_address after a rewrite during a verify. When this bug was
3299 fixed, sender_address at this point became the rewritten address. I'm not sure
3300 this is what should be logged, so I've changed to logging the unrewritten
3301 address to retain backward compatibility. */
3305 #ifdef WITH_CONTENT_SCAN
3306 case ACL_WHERE_MIME: what = US"during MIME ACL checks"; break;
3308 case ACL_WHERE_PREDATA: what = US"DATA"; break;
3309 case ACL_WHERE_DATA: what = US"after DATA"; break;
3310 #ifndef DISABLE_PRDR
3311 case ACL_WHERE_PRDR: what = US"after DATA PRDR"; break;
3315 uschar * place = smtp_cmd_data ? smtp_cmd_data : US"in \"connect\" ACL";
3318 if (where == ACL_WHERE_AUTH) /* avoid logging auth creds */
3321 for (s = smtp_cmd_data; *s && !isspace(*s); ) s++;
3322 lim = s - smtp_cmd_data; /* atop after method */
3324 what = string_sprintf("%s %.*s", acl_wherenames[where], lim, place);
3329 case ACL_WHERE_RCPT:
3330 case ACL_WHERE_DATA:
3331 #ifdef WITH_CONTENT_SCAN
3332 case ACL_WHERE_MIME:
3334 sender_info = string_sprintf("F=<%s>%s%s%s%s ",
3335 sender_address_unrewritten ? sender_address_unrewritten : sender_address,
3336 sender_host_authenticated ? US" A=" : US"",
3337 sender_host_authenticated ? sender_host_authenticated : US"",
3338 sender_host_authenticated && authenticated_id ? US":" : US"",
3339 sender_host_authenticated && authenticated_id ? authenticated_id : US""
3344 /* If there's been a sender verification failure with a specific message, and
3345 we have not sent a response about it yet, do so now, as a preliminary line for
3346 failures, but not defers. However, always log it for defer, and log it for fail
3347 unless the sender_verify_fail log selector has been turned off. */
3349 if (sender_verified_failed &&
3350 !testflag(sender_verified_failed, af_sverify_told))
3352 BOOL save_rcpt_in_progress = fl.rcpt_in_progress;
3353 fl.rcpt_in_progress = FALSE; /* So as not to treat these as the error */
3355 setflag(sender_verified_failed, af_sverify_told);
3357 if (rc != FAIL || LOGGING(sender_verify_fail))
3358 log_write(0, LOG_MAIN|LOG_REJECT, "%s sender verify %s for <%s>%s",
3359 host_and_ident(TRUE),
3360 ((sender_verified_failed->special_action & 255) == DEFER)? "defer":"fail",
3361 sender_verified_failed->address,
3362 (sender_verified_failed->message == NULL)? US"" :
3363 string_sprintf(": %s", sender_verified_failed->message));
3365 if (rc == FAIL && sender_verified_failed->user_message)
3366 smtp_respond(smtp_code, codelen, FALSE, string_sprintf(
3367 testflag(sender_verified_failed, af_verify_pmfail)?
3368 "Postmaster verification failed while checking <%s>\n%s\n"
3369 "Several RFCs state that you are required to have a postmaster\n"
3370 "mailbox for each mail domain. This host does not accept mail\n"
3371 "from domains whose servers reject the postmaster address."
3373 testflag(sender_verified_failed, af_verify_nsfail)?
3374 "Callback setup failed while verifying <%s>\n%s\n"
3375 "The initial connection, or a HELO or MAIL FROM:<> command was\n"
3376 "rejected. Refusing MAIL FROM:<> does not help fight spam, disregards\n"
3377 "RFC requirements, and stops you from receiving standard bounce\n"
3378 "messages. This host does not accept mail from domains whose servers\n"
3381 "Verification failed for <%s>\n%s",
3382 sender_verified_failed->address,
3383 sender_verified_failed->user_message));
3385 fl.rcpt_in_progress = save_rcpt_in_progress;
3388 /* Sort out text for logging */
3390 log_msg = log_msg ? string_sprintf(": %s", log_msg) : US"";
3391 if ((lognl = Ustrchr(log_msg, '\n'))) *lognl = 0;
3393 /* Send permanent failure response to the command, but the code used isn't
3394 always a 5xx one - see comments at the start of this function. If the original
3395 rc was FAIL_DROP we drop the connection and yield 2. */
3398 smtp_respond(smtp_code, codelen, TRUE,
3399 user_msg ? user_msg : US"Administrative prohibition");
3401 /* Send temporary failure response to the command. Don't give any details,
3402 unless acl_temp_details is set. This is TRUE for a callout defer, a "defer"
3403 verb, and for a header verify when smtp_return_error_details is set.
3405 This conditional logic is all somewhat of a mess because of the odd
3406 interactions between temp_details and return_error_details. One day it should
3407 be re-implemented in a tidier fashion. */
3410 if (f.acl_temp_details && user_msg)
3412 if ( smtp_return_error_details
3413 && sender_verified_failed
3414 && sender_verified_failed->message
3416 smtp_respond(smtp_code, codelen, FALSE, sender_verified_failed->message);
3418 smtp_respond(smtp_code, codelen, TRUE, user_msg);
3421 smtp_respond(smtp_code, codelen, TRUE,
3422 US"Temporary local problem - please try later");
3424 /* Log the incident to the logs that are specified by log_reject_target
3425 (default main, reject). This can be empty to suppress logging of rejections. If
3426 the connection is not forcibly to be dropped, return 0. Otherwise, log why it
3427 is closing if required and return 2. */
3429 if (log_reject_target != 0)
3432 gstring * g = s_tlslog(NULL);
3433 uschar * tls = string_from_gstring(g);
3434 if (!tls) tls = US"";
3436 uschar * tls = US"";
3438 log_write(where == ACL_WHERE_CONNECT ? L_connection_reject : 0,
3439 log_reject_target, "%s%s%s %s%srejected %s%s",
3440 LOGGING(dnssec) && sender_host_dnssec ? US" DS" : US"",
3441 host_and_ident(TRUE),
3444 rc == FAIL ? US"" : US"temporarily ",
3448 if (!drop) return 0;
3450 log_write(L_smtp_connection, LOG_MAIN, "%s closed by DROP in ACL",
3451 smtp_get_connection_info());
3453 /* Run the not-quit ACL, but without any custom messages. This should not be a
3454 problem, because we get here only if some other ACL has issued "drop", and
3455 in that case, *its* custom messages will have been used above. */
3457 smtp_notquit_exit(US"acl-drop", NULL, NULL);
3464 /*************************************************
3465 * Handle SMTP exit when QUIT is not given *
3466 *************************************************/
3468 /* This function provides a logging/statistics hook for when an SMTP connection
3469 is dropped on the floor or the other end goes away. It's a global function
3470 because it's called from receive.c as well as this module. As well as running
3471 the NOTQUIT ACL, if there is one, this function also outputs a final SMTP
3472 response, either with a custom message from the ACL, or using a default. There
3473 is one case, however, when no message is output - after "drop". In that case,
3474 the ACL that obeyed "drop" has already supplied the custom message, and NULL is
3475 passed to this function.
3477 In case things go wrong while processing this function, causing an error that
3478 may re-enter this function, there is a recursion check.
3481 reason What $smtp_notquit_reason will be set to in the ACL;
3482 if NULL, the ACL is not run
3483 code The error code to return as part of the response
3484 defaultrespond The default message if there's no user_msg
3490 smtp_notquit_exit(uschar *reason, uschar *code, uschar *defaultrespond, ...)
3493 uschar *user_msg = NULL;
3494 uschar *log_msg = NULL;
3496 /* Check for recursive call */
3498 if (fl.smtp_exit_function_called)
3500 log_write(0, LOG_PANIC, "smtp_notquit_exit() called more than once (%s)",
3504 fl.smtp_exit_function_called = TRUE;
3506 /* Call the not-QUIT ACL, if there is one, unless no reason is given. */
3508 if (acl_smtp_notquit && reason)
3510 smtp_notquit_reason = reason;
3511 if ((rc = acl_check(ACL_WHERE_NOTQUIT, NULL, acl_smtp_notquit, &user_msg,
3512 &log_msg)) == ERROR)
3513 log_write(0, LOG_MAIN|LOG_PANIC, "ACL for not-QUIT returned ERROR: %s",
3517 /* If the connection was dropped, we certainly are no longer talking TLS */
3518 tls_in.active.sock = -1;
3520 /* Write an SMTP response if we are expected to give one. As the default
3521 responses are all internal, they should be reasonable size. */
3523 if (code && defaultrespond)
3526 smtp_respond(code, 3, TRUE, user_msg);
3532 va_start(ap, defaultrespond);
3533 g = string_vformat(NULL, SVFMT_EXTEND|SVFMT_REBUFFER, CS defaultrespond, ap);
3535 smtp_printf("%s %s\r\n", FALSE, code, string_from_gstring(g));
3544 /*************************************************
3545 * Verify HELO argument *
3546 *************************************************/
3548 /* This function is called if helo_verify_hosts or helo_try_verify_hosts is
3549 matched. It is also called from ACL processing if verify = helo is used and
3550 verification was not previously tried (i.e. helo_try_verify_hosts was not
3551 matched). The result of its processing is to set helo_verified and
3552 helo_verify_failed. These variables should both be FALSE for this function to
3555 Note that EHLO/HELO is legitimately allowed to quote an address literal. Allow
3556 for IPv6 ::ffff: literals.
3559 Returns: TRUE if testing was completed;
3560 FALSE on a temporary failure
3564 smtp_verify_helo(void)
3568 HDEBUG(D_receive) debug_printf("verifying EHLO/HELO argument \"%s\"\n",
3571 if (sender_helo_name == NULL)
3573 HDEBUG(D_receive) debug_printf("no EHLO/HELO command was issued\n");
3576 /* Deal with the case of -bs without an IP address */
3578 else if (sender_host_address == NULL)
3580 HDEBUG(D_receive) debug_printf("no client IP address: assume success\n");
3581 f.helo_verified = TRUE;
3584 /* Deal with the more common case when there is a sending IP address */
3586 else if (sender_helo_name[0] == '[')
3588 f.helo_verified = Ustrncmp(sender_helo_name+1, sender_host_address,
3589 Ustrlen(sender_host_address)) == 0;
3592 if (!f.helo_verified)
3594 if (strncmpic(sender_host_address, US"::ffff:", 7) == 0)
3595 f.helo_verified = Ustrncmp(sender_helo_name + 1,
3596 sender_host_address + 7, Ustrlen(sender_host_address) - 7) == 0;
3601 { if (f.helo_verified) debug_printf("matched host address\n"); }
3604 /* Do a reverse lookup if one hasn't already given a positive or negative
3605 response. If that fails, or the name doesn't match, try checking with a forward
3610 if (sender_host_name == NULL && !host_lookup_failed)
3611 yield = host_name_lookup() != DEFER;
3613 /* If a host name is known, check it and all its aliases. */
3615 if (sender_host_name)
3616 if ((f.helo_verified = strcmpic(sender_host_name, sender_helo_name) == 0))
3618 sender_helo_dnssec = sender_host_dnssec;
3619 HDEBUG(D_receive) debug_printf("matched host name\n");
3623 uschar **aliases = sender_host_aliases;
3625 if ((f.helo_verified = strcmpic(*aliases++, sender_helo_name) == 0))
3627 sender_helo_dnssec = sender_host_dnssec;
3631 HDEBUG(D_receive) if (f.helo_verified)
3632 debug_printf("matched alias %s\n", *(--aliases));
3635 /* Final attempt: try a forward lookup of the helo name */
3637 if (!f.helo_verified)
3641 {.name = sender_helo_name, .address = NULL, .mx = MX_NONE, .next = NULL};
3643 {.request = US"*", .require = US""};
3645 HDEBUG(D_receive) debug_printf("getting IP address for %s\n",
3647 rc = host_find_bydns(&h, NULL, HOST_FIND_BY_A | HOST_FIND_BY_AAAA,
3648 NULL, NULL, NULL, &d, NULL, NULL);
3649 if (rc == HOST_FOUND || rc == HOST_FOUND_LOCAL)
3650 for (host_item * hh = &h; hh; hh = hh->next)
3651 if (Ustrcmp(hh->address, sender_host_address) == 0)
3653 f.helo_verified = TRUE;
3654 if (h.dnssec == DS_YES) sender_helo_dnssec = TRUE;
3656 debug_printf("IP address for %s matches calling address\n"
3657 "Forward DNS security status: %sverified\n",
3658 sender_helo_name, sender_helo_dnssec ? "" : "un");
3664 if (!f.helo_verified) f.helo_verify_failed = TRUE; /* We've tried ... */
3671 /*************************************************
3672 * Send user response message *
3673 *************************************************/
3675 /* This function is passed a default response code and a user message. It calls
3676 smtp_message_code() to check and possibly modify the response code, and then
3677 calls smtp_respond() to transmit the response. I put this into a function
3678 just to avoid a lot of repetition.
3681 code the response code
3682 user_msg the user message
3688 smtp_user_msg(uschar *code, uschar *user_msg)
3691 smtp_message_code(&code, &len, &user_msg, NULL, TRUE);
3692 smtp_respond(code, len, TRUE, user_msg);
3698 smtp_in_auth(auth_instance *au, uschar ** s, uschar ** ss)
3700 const uschar *set_id = NULL;
3703 /* Run the checking code, passing the remainder of the command line as
3704 data. Initials the $auth<n> variables as empty. Initialize $0 empty and set
3705 it as the only set numerical variable. The authenticator may set $auth<n>
3706 and also set other numeric variables. The $auth<n> variables are preferred
3707 nowadays; the numerical variables remain for backwards compatibility.
3709 Afterwards, have a go at expanding the set_id string, even if
3710 authentication failed - for bad passwords it can be useful to log the
3711 userid. On success, require set_id to expand and exist, and put it in
3712 authenticated_id. Save this in permanent store, as the working store gets
3713 reset at HELO, RSET, etc. */
3715 for (int i = 0; i < AUTH_VARS; i++) auth_vars[i] = NULL;
3717 expand_nlength[0] = 0; /* $0 contains nothing */
3719 rc = (au->info->servercode)(au, smtp_cmd_data);
3720 if (au->set_id) set_id = expand_string(au->set_id);
3721 expand_nmax = -1; /* Reset numeric variables */
3722 for (int i = 0; i < AUTH_VARS; i++) auth_vars[i] = NULL; /* Reset $auth<n> */
3724 /* The value of authenticated_id is stored in the spool file and printed in
3725 log lines. It must not contain binary zeros or newline characters. In
3726 normal use, it never will, but when playing around or testing, this error
3727 can (did) happen. To guard against this, ensure that the id contains only
3728 printing characters. */
3730 if (set_id) set_id = string_printing(set_id);
3732 /* For the non-OK cases, set up additional logging data if set_id
3736 set_id = set_id && *set_id
3737 ? string_sprintf(" (set_id=%s)", set_id) : US"";
3739 /* Switch on the result */
3744 if (!au->set_id || set_id) /* Complete success */
3746 if (set_id) authenticated_id = string_copy_perm(set_id, TRUE);
3747 sender_host_authenticated = au->name;
3748 sender_host_auth_pubname = au->public_name;
3749 authentication_failed = FALSE;
3750 authenticated_fail_id = NULL; /* Impossible to already be set? */
3753 (sender_host_address ? protocols : protocols_local)
3754 [pextend + pauthed + (tls_in.active.sock >= 0 ? pcrpted:0)];
3755 *s = *ss = US"235 Authentication succeeded";
3756 authenticated_by = au;
3760 /* Authentication succeeded, but we failed to expand the set_id string.
3761 Treat this as a temporary error. */
3763 auth_defer_msg = expand_string_message;
3767 if (set_id) authenticated_fail_id = string_copy_perm(set_id, TRUE);
3768 *s = string_sprintf("435 Unable to authenticate at present%s",
3769 auth_defer_user_msg);
3770 *ss = string_sprintf("435 Unable to authenticate at present%s: %s",
3771 set_id, auth_defer_msg);
3775 *s = *ss = US"501 Invalid base64 data";
3779 *s = *ss = US"501 Authentication cancelled";
3783 *s = *ss = US"553 Initial data not expected";
3787 if (set_id) authenticated_fail_id = string_copy_perm(set_id, TRUE);
3788 *s = US"535 Incorrect authentication data";
3789 *ss = string_sprintf("535 Incorrect authentication data%s", set_id);
3793 if (set_id) authenticated_fail_id = string_copy_perm(set_id, TRUE);
3794 *s = US"435 Internal error";
3795 *ss = string_sprintf("435 Internal error%s: return %d from authentication "
3796 "check", set_id, rc);
3808 qualify_recipient(uschar ** recipient, uschar * smtp_cmd_data, uschar * tag)
3811 if (f.allow_unqualified_recipient || strcmpic(*recipient, US"postmaster") == 0)
3813 DEBUG(D_receive) debug_printf("unqualified address %s accepted\n",
3815 rd = Ustrlen(recipient) + 1;
3816 *recipient = rewrite_address_qualify(*recipient, TRUE);
3819 smtp_printf("501 %s: recipient address must contain a domain\r\n", FALSE,
3821 log_write(L_smtp_syntax_error,
3822 LOG_MAIN|LOG_REJECT, "unqualified %s rejected: <%s> %s%s",
3823 tag, *recipient, host_and_ident(TRUE), host_lookup_msg);
3831 smtp_quit_handler(uschar ** user_msgp, uschar ** log_msgp)
3834 f.smtp_in_quit = TRUE;
3835 incomplete_transaction_log(US"QUIT");
3837 && acl_check(ACL_WHERE_QUIT, NULL, acl_smtp_quit, user_msgp, log_msgp)
3839 log_write(0, LOG_MAIN|LOG_PANIC, "ACL for QUIT returned ERROR: %s",
3842 #ifdef EXIM_TCP_CORK
3843 (void) setsockopt(fileno(smtp_out), IPPROTO_TCP, EXIM_TCP_CORK, US &on, sizeof(on));
3847 smtp_respond(US"221", 3, TRUE, *user_msgp);
3849 smtp_printf("221 %s closing connection\r\n", FALSE, smtp_active_hostname);
3851 #ifdef SERVERSIDE_CLOSE_NOWAIT
3852 # ifndef DISABLE_TLS
3853 tls_close(NULL, TLS_SHUTDOWN_NOWAIT);
3856 log_write(L_smtp_connection, LOG_MAIN, "%s closed by QUIT",
3857 smtp_get_connection_info());
3860 # ifndef DISABLE_TLS
3861 tls_close(NULL, TLS_SHUTDOWN_WAIT);
3864 log_write(L_smtp_connection, LOG_MAIN, "%s closed by QUIT",
3865 smtp_get_connection_info());
3867 /* Pause, hoping client will FIN first so that they get the TIME_WAIT.
3868 The socket should become readble (though with no data) */
3871 int fd = fileno(smtp_in);
3873 struct timeval t_limit = {.tv_sec = 0, .tv_usec = 200*1000};
3877 (void) select(fd + 1, (SELECT_ARG2_TYPE *)&fds, NULL, NULL, &t_limit);
3879 #endif /*!DAEMON_CLOSE_NOWAIT*/
3884 smtp_rset_handler(void)
3887 incomplete_transaction_log(US"RSET");
3888 smtp_printf("250 Reset OK\r\n", FALSE);
3889 cmd_list[CMD_LIST_RSET].is_mail_cmd = FALSE;
3894 expand_mailmax(const uschar * s)
3896 if (!(s = expand_cstring(s)))
3897 log_write(0, LOG_MAIN|LOG_PANIC, "failed to expand smtp_accept_max_per_connection");
3898 return *s ? Uatoi(s) : 0;
3901 /*************************************************
3902 * Initialize for SMTP incoming message *
3903 *************************************************/
3905 /* This function conducts the initial dialogue at the start of an incoming SMTP
3906 message, and builds a list of recipients. However, if the incoming message
3907 is part of a batch (-bS option) a separate function is called since it would
3908 be messy having tests splattered about all over this function. This function
3909 therefore handles the case where interaction is occurring. The input and output
3910 files are set up in smtp_in and smtp_out.
3912 The global recipients_list is set to point to a vector of recipient_item
3913 blocks, whose number is given by recipients_count. This is extended by the
3914 receive_add_recipient() function. The global variable sender_address is set to
3915 the sender's address. The yield is +1 if a message has been successfully
3916 started, 0 if a QUIT command was encountered or the connection was refused from
3917 the particular host, or -1 if the connection was lost.
3921 Returns: > 0 message successfully started (reached DATA)
3922 = 0 QUIT read or end of file reached or call refused
3927 smtp_setup_msg(void)
3931 BOOL toomany = FALSE;
3932 BOOL discarded = FALSE;
3933 BOOL last_was_rej_mail = FALSE;
3934 BOOL last_was_rcpt = FALSE;
3935 rmark reset_point = store_mark();
3937 DEBUG(D_receive) debug_printf("smtp_setup_msg entered\n");
3939 /* Reset for start of new message. We allow one RSET not to be counted as a
3940 nonmail command, for those MTAs that insist on sending it between every
3941 message. Ditto for EHLO/HELO and for STARTTLS, to allow for going in and out of
3942 TLS between messages (an Exim client may do this if it has messages queued up
3943 for the host). Note: we do NOT reset AUTH at this point. */
3945 reset_point = smtp_reset(reset_point);
3946 message_ended = END_NOTSTARTED;
3948 chunking_state = f.chunking_offered ? CHUNKING_OFFERED : CHUNKING_NOT_OFFERED;
3950 cmd_list[CMD_LIST_RSET].is_mail_cmd = TRUE;
3951 cmd_list[CMD_LIST_HELO].is_mail_cmd = TRUE;
3952 cmd_list[CMD_LIST_EHLO].is_mail_cmd = TRUE;
3954 cmd_list[CMD_LIST_STARTTLS].is_mail_cmd = TRUE;
3957 /* Set the local signal handler for SIGTERM - it tries to end off tidily */
3959 had_command_sigterm = 0;
3960 os_non_restarting_signal(SIGTERM, command_sigterm_handler);
3962 /* Batched SMTP is handled in a different function. */
3964 if (smtp_batched_input) return smtp_setup_batch_msg();
3967 if (smtp_in) /* Avoid pure-ACKs while in cmd pingpong phase */
3968 (void) setsockopt(fileno(smtp_in), IPPROTO_TCP, TCP_QUICKACK,
3969 US &off, sizeof(off));
3972 /* Deal with SMTP commands. This loop is exited by setting done to a POSITIVE
3973 value. The values are 2 larger than the required yield of the function. */
3977 const uschar **argv;
3978 uschar *etrn_command;
3979 uschar *etrn_serialize_key;
3981 uschar *log_msg, *smtp_code;
3982 uschar *user_msg = NULL;
3983 uschar *recipient = NULL;
3984 uschar *hello = NULL;
3986 BOOL was_rej_mail = FALSE;
3987 BOOL was_rcpt = FALSE;
3988 void (*oldsignal)(int);
3990 int start, end, sender_domain, recipient_domain;
3993 uschar *orcpt = NULL;
3998 /* Check once per STARTTLS or SSL-on-connect for a TLS AUTH */
3999 if ( tls_in.active.sock >= 0
4001 && tls_in.certificate_verified
4002 && cmd_list[CMD_LIST_TLS_AUTH].is_mail_cmd
4005 cmd_list[CMD_LIST_TLS_AUTH].is_mail_cmd = FALSE;
4007 for (auth_instance * au = auths; au; au = au->next)
4008 if (strcmpic(US"tls", au->driver_name) == 0)
4011 && (rc = acl_check(ACL_WHERE_AUTH, NULL, acl_smtp_auth,
4012 &user_msg, &log_msg)) != OK
4014 done = smtp_handle_acl_fail(ACL_WHERE_AUTH, rc, user_msg, log_msg);
4017 smtp_cmd_data = NULL;
4019 if (smtp_in_auth(au, &s, &ss) == OK)
4020 { DEBUG(D_auth) debug_printf("tls auth succeeded\n"); }
4022 { DEBUG(D_auth) debug_printf("tls auth not succeeded\n"); }
4029 switch(smtp_read_command(
4030 #ifndef DISABLE_PIPE_CONNECT
4031 !fl.pipe_connect_acceptable,
4035 GETC_BUFFER_UNLIMITED))
4037 /* The AUTH command is not permitted to occur inside a transaction, and may
4038 occur successfully only once per connection. Actually, that isn't quite
4039 true. When TLS is started, all previous information about a connection must
4040 be discarded, so a new AUTH is permitted at that time.
4042 AUTH may only be used when it has been advertised. However, it seems that
4043 there are clients that send AUTH when it hasn't been advertised, some of
4044 them even doing this after HELO. And there are MTAs that accept this. Sigh.
4045 So there's a get-out that allows this to happen.
4047 AUTH is initially labelled as a "nonmail command" so that one occurrence
4048 doesn't get counted. We change the label here so that multiple failing
4049 AUTHS will eventually hit the nonmail threshold. */
4053 authentication_failed = TRUE;
4054 cmd_list[CMD_LIST_AUTH].is_mail_cmd = FALSE;
4056 if (!fl.auth_advertised && !f.allow_auth_unadvertised)
4058 done = synprot_error(L_smtp_protocol_error, 503, NULL,
4059 US"AUTH command used when not advertised");
4062 if (sender_host_authenticated)
4064 done = synprot_error(L_smtp_protocol_error, 503, NULL,
4065 US"already authenticated");
4070 done = synprot_error(L_smtp_protocol_error, 503, NULL,
4071 US"not permitted in mail transaction");
4078 && (rc = acl_check(ACL_WHERE_AUTH, NULL, acl_smtp_auth,
4079 &user_msg, &log_msg)) != OK
4082 done = smtp_handle_acl_fail(ACL_WHERE_AUTH, rc, user_msg, log_msg);
4086 /* Find the name of the requested authentication mechanism. */
4089 for (; (c = *smtp_cmd_data) && !isspace(c); smtp_cmd_data++)
4090 if (!isalnum(c) && c != '-' && c != '_')
4092 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4093 US"invalid character in authentication mechanism name");
4097 /* If not at the end of the line, we must be at white space. Terminate the
4098 name and move the pointer on to any data that may be present. */
4102 *smtp_cmd_data++ = 0;
4103 while (isspace(*smtp_cmd_data)) smtp_cmd_data++;
4106 /* Search for an authentication mechanism which is configured for use
4107 as a server and which has been advertised (unless, sigh, allow_auth_
4108 unadvertised is set). */
4112 for (au = auths; au; au = au->next)
4113 if (strcmpic(s, au->public_name) == 0 && au->server &&
4114 (au->advertised || f.allow_auth_unadvertised))
4119 c = smtp_in_auth(au, &s, &ss);
4121 smtp_printf("%s\r\n", FALSE, s);
4123 log_write(0, LOG_MAIN|LOG_REJECT, "%s authenticator failed for %s: %s",
4124 au->name, host_and_ident(FALSE), ss);
4127 done = synprot_error(L_smtp_protocol_error, 504, NULL,
4128 string_sprintf("%s authentication mechanism not supported", s));
4131 break; /* AUTH_CMD */
4133 /* The HELO/EHLO commands are permitted to appear in the middle of a
4134 session as well as at the beginning. They have the effect of a reset in
4135 addition to their other functions. Their absence at the start cannot be
4136 taken to be an error.
4140 If the EHLO command is not acceptable to the SMTP server, 501, 500,
4141 or 502 failure replies MUST be returned as appropriate. The SMTP
4142 server MUST stay in the same state after transmitting these replies
4143 that it was in before the EHLO was received.
4145 Therefore, we do not do the reset until after checking the command for
4146 acceptability. This change was made for Exim release 4.11. Previously
4147 it did the reset first. */
4160 HELO_EHLO: /* Common code for HELO and EHLO */
4161 cmd_list[CMD_LIST_HELO].is_mail_cmd = FALSE;
4162 cmd_list[CMD_LIST_EHLO].is_mail_cmd = FALSE;
4164 /* Reject the HELO if its argument was invalid or non-existent. A
4165 successful check causes the argument to be saved in malloc store. */
4167 if (!check_helo(smtp_cmd_data))
4169 smtp_printf("501 Syntactically invalid %s argument(s)\r\n", FALSE, hello);
4171 log_write(0, LOG_MAIN|LOG_REJECT, "rejected %s from %s: syntactically "
4172 "invalid argument(s): %s", hello, host_and_ident(FALSE),
4173 *smtp_cmd_argument == 0 ? US"(no argument given)" :
4174 string_printing(smtp_cmd_argument));
4176 if (++synprot_error_count > smtp_max_synprot_errors)
4178 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
4179 "syntax or protocol errors (last command was \"%s\", %s)",
4180 host_and_ident(FALSE), string_printing(smtp_cmd_buffer),
4181 string_from_gstring(s_connhad_log(NULL))
4189 /* If sender_host_unknown is true, we have got here via the -bs interface,
4190 not called from inetd. Otherwise, we are running an IP connection and the
4191 host address will be set. If the helo name is the primary name of this
4192 host and we haven't done a reverse lookup, force one now. If helo_required
4193 is set, ensure that the HELO name matches the actual host. If helo_verify
4194 is set, do the same check, but softly. */
4196 if (!f.sender_host_unknown)
4198 BOOL old_helo_verified = f.helo_verified;
4199 uschar *p = smtp_cmd_data;
4201 while (*p != 0 && !isspace(*p)) { *p = tolower(*p); p++; }
4204 /* Force a reverse lookup if HELO quoted something in helo_lookup_domains
4205 because otherwise the log can be confusing. */
4207 if ( !sender_host_name
4208 && match_isinlist(sender_helo_name, CUSS &helo_lookup_domains, 0,
4209 &domainlist_anchor, NULL, MCL_DOMAIN, TRUE, NULL) == OK)
4210 (void)host_name_lookup();
4212 /* Rebuild the fullhost info to include the HELO name (and the real name
4213 if it was looked up.) */
4215 host_build_sender_fullhost(); /* Rebuild */
4216 set_process_info("handling%s incoming connection from %s",
4217 tls_in.active.sock >= 0 ? " TLS" : "", host_and_ident(FALSE));
4219 /* Verify if configured. This doesn't give much security, but it does
4220 make some people happy to be able to do it. If helo_required is set,
4221 (host matches helo_verify_hosts) failure forces rejection. If helo_verify
4222 is set (host matches helo_try_verify_hosts), it does not. This is perhaps
4223 now obsolescent, since the verification can now be requested selectively
4226 f.helo_verified = f.helo_verify_failed = sender_helo_dnssec = FALSE;
4227 if (fl.helo_required || fl.helo_verify)
4229 BOOL tempfail = !smtp_verify_helo();
4230 if (!f.helo_verified)
4232 if (fl.helo_required)
4234 smtp_printf("%d %s argument does not match calling host\r\n", FALSE,
4235 tempfail? 451 : 550, hello);
4236 log_write(0, LOG_MAIN|LOG_REJECT, "%srejected \"%s %s\" from %s",
4237 tempfail? "temporarily " : "",
4238 hello, sender_helo_name, host_and_ident(FALSE));
4239 f.helo_verified = old_helo_verified;
4240 break; /* End of HELO/EHLO processing */
4242 HDEBUG(D_all) debug_printf("%s verification failed but host is in "
4243 "helo_try_verify_hosts\n", hello);
4249 /* set up SPF context */
4250 spf_conn_init(sender_helo_name, sender_host_address);
4253 /* Apply an ACL check if one is defined; afterwards, recheck
4254 synchronization in case the client started sending in a delay. */
4257 if ((rc = acl_check(ACL_WHERE_HELO, NULL, acl_smtp_helo,
4258 &user_msg, &log_msg)) != OK)
4260 done = smtp_handle_acl_fail(ACL_WHERE_HELO, rc, user_msg, log_msg);
4261 sender_helo_name = NULL;
4262 host_build_sender_fullhost(); /* Rebuild */
4265 #ifndef DISABLE_PIPE_CONNECT
4266 else if (!fl.pipe_connect_acceptable && !check_sync())
4268 else if (!check_sync())
4272 /* Generate an OK reply. The default string includes the ident if present,
4273 and also the IP address if present. Reflecting back the ident is intended
4274 as a deterrent to mail forgers. For maximum efficiency, and also because
4275 some broken systems expect each response to be in a single packet, arrange
4276 that the entire reply is sent in one write(). */
4278 fl.auth_advertised = FALSE;
4279 f.smtp_in_pipelining_advertised = FALSE;
4281 fl.tls_advertised = FALSE;
4283 fl.dsn_advertised = FALSE;
4285 fl.smtputf8_advertised = FALSE;
4288 /* Expand the per-connection message count limit option */
4289 mailmax = expand_mailmax(smtp_accept_max_per_connection);
4291 smtp_code = US"250 "; /* Default response code plus space*/
4294 /* sender_host_name below will be tainted, so save on copy when we hit it */
4295 g = string_get_tainted(24, TRUE);
4296 g = string_fmt_append(g, "%.3s %s Hello %s%s%s",
4298 smtp_active_hostname,
4299 sender_ident ? sender_ident : US"",
4300 sender_ident ? US" at " : US"",
4301 sender_host_name ? sender_host_name : sender_helo_name);
4303 if (sender_host_address)
4304 g = string_fmt_append(g, " [%s]", sender_host_address);
4307 /* A user-supplied EHLO greeting may not contain more than one line. Note
4308 that the code returned by smtp_message_code() includes the terminating
4309 whitespace character. */
4315 smtp_message_code(&smtp_code, &codelen, &user_msg, NULL, TRUE);
4316 s = string_sprintf("%.*s%s", codelen, smtp_code, user_msg);
4317 if ((ss = strpbrk(CS s, "\r\n")) != NULL)
4319 log_write(0, LOG_MAIN|LOG_PANIC, "EHLO/HELO response must not contain "
4320 "newlines: message truncated: %s", string_printing(s));
4323 g = string_cat(NULL, s);
4326 g = string_catn(g, US"\r\n", 2);
4328 /* If we received EHLO, we must create a multiline response which includes
4329 the functions supported. */
4335 /* I'm not entirely happy with this, as an MTA is supposed to check
4336 that it has enough room to accept a message of maximum size before
4337 it sends this. However, there seems little point in not sending it.
4338 The actual size check happens later at MAIL FROM time. By postponing it
4339 till then, VRFY and EXPN can be used after EHLO when space is short. */
4341 if (thismessage_size_limit > 0)
4342 g = string_fmt_append(g, "%.3s-SIZE %d\r\n", smtp_code,
4343 thismessage_size_limit);
4346 g = string_catn(g, smtp_code, 3);
4347 g = string_catn(g, US"-SIZE\r\n", 7);
4350 #ifdef EXPERIMENTAL_ESMTP_LIMITS
4351 if ( (mailmax > 0 || recipients_max)
4352 && verify_check_host(&limits_advertise_hosts) == OK)
4354 g = string_fmt_append(g, "%.3s-LIMITS", smtp_code);
4356 g = string_fmt_append(g, " MAILMAX=%d", mailmax);
4358 g = string_fmt_append(g, " RCPTMAX=%d", recipients_max);
4359 g = string_catn(g, US"\r\n", 2);
4363 /* Exim does not do protocol conversion or data conversion. It is 8-bit
4364 clean; if it has an 8-bit character in its hand, it just sends it. It
4365 cannot therefore specify 8BITMIME and remain consistent with the RFCs.
4366 However, some users want this option simply in order to stop MUAs
4367 mangling messages that contain top-bit-set characters. It is therefore
4368 provided as an option. */
4370 if (accept_8bitmime)
4372 g = string_catn(g, smtp_code, 3);
4373 g = string_catn(g, US"-8BITMIME\r\n", 11);
4376 /* Advertise DSN support if configured to do so. */
4377 if (verify_check_host(&dsn_advertise_hosts) != FAIL)
4379 g = string_catn(g, smtp_code, 3);
4380 g = string_catn(g, US"-DSN\r\n", 6);
4381 fl.dsn_advertised = TRUE;
4384 /* Advertise ETRN/VRFY/EXPN if there's are ACL checking whether a host is
4385 permitted to issue them; a check is made when any host actually tries. */
4389 g = string_catn(g, smtp_code, 3);
4390 g = string_catn(g, US"-ETRN\r\n", 7);
4394 g = string_catn(g, smtp_code, 3);
4395 g = string_catn(g, US"-VRFY\r\n", 7);
4399 g = string_catn(g, smtp_code, 3);
4400 g = string_catn(g, US"-EXPN\r\n", 7);
4403 /* Exim is quite happy with pipelining, so let the other end know that
4404 it is safe to use it, unless advertising is disabled. */
4406 if ( f.pipelining_enable
4407 && verify_check_host(&pipelining_advertise_hosts) == OK)
4409 g = string_catn(g, smtp_code, 3);
4410 g = string_catn(g, US"-PIPELINING\r\n", 13);
4411 sync_cmd_limit = NON_SYNC_CMD_PIPELINING;
4412 f.smtp_in_pipelining_advertised = TRUE;
4414 #ifndef DISABLE_PIPE_CONNECT
4415 if (fl.pipe_connect_acceptable)
4417 f.smtp_in_early_pipe_advertised = TRUE;
4418 g = string_catn(g, smtp_code, 3);
4419 g = string_catn(g, US"-" EARLY_PIPE_FEATURE_NAME "\r\n", EARLY_PIPE_FEATURE_LEN+3);
4425 /* If any server authentication mechanisms are configured, advertise
4426 them if the current host is in auth_advertise_hosts. The problem with
4427 advertising always is that some clients then require users to
4428 authenticate (and aren't configurable otherwise) even though it may not
4429 be necessary (e.g. if the host is in host_accept_relay).
4431 RFC 2222 states that SASL mechanism names contain only upper case
4432 letters, so output the names in upper case, though we actually recognize
4433 them in either case in the AUTH command. */
4437 && !sender_host_authenticated
4439 && verify_check_host(&auth_advertise_hosts) == OK
4443 for (auth_instance * au = auths; au; au = au->next)
4445 au->advertised = FALSE;
4448 DEBUG(D_auth+D_expand) debug_printf_indent(
4449 "Evaluating advertise_condition for %s %s athenticator\n",
4450 au->name, au->public_name);
4451 if ( !au->advertise_condition
4452 || expand_check_condition(au->advertise_condition, au->name,
4459 g = string_catn(g, smtp_code, 3);
4460 g = string_catn(g, US"-AUTH", 5);
4462 fl.auth_advertised = TRUE;
4465 g = string_catn(g, US" ", 1);
4466 g = string_cat (g, au->public_name);
4467 while (++saveptr < g->ptr) g->s[saveptr] = toupper(g->s[saveptr]);
4468 au->advertised = TRUE;
4473 if (!first) g = string_catn(g, US"\r\n", 2);
4476 /* RFC 3030 CHUNKING */
4478 if (verify_check_host(&chunking_advertise_hosts) != FAIL)
4480 g = string_catn(g, smtp_code, 3);
4481 g = string_catn(g, US"-CHUNKING\r\n", 11);
4482 f.chunking_offered = TRUE;
4483 chunking_state = CHUNKING_OFFERED;
4486 /* Advertise TLS (Transport Level Security) aka SSL (Secure Socket Layer)
4487 if it has been included in the binary, and the host matches
4488 tls_advertise_hosts. We must *not* advertise if we are already in a
4489 secure connection. */
4492 if (tls_in.active.sock < 0 &&
4493 verify_check_host(&tls_advertise_hosts) != FAIL)
4495 g = string_catn(g, smtp_code, 3);
4496 g = string_catn(g, US"-STARTTLS\r\n", 11);
4497 fl.tls_advertised = TRUE;
4501 #ifndef DISABLE_PRDR
4502 /* Per Recipient Data Response, draft by Eric A. Hall extending RFC */
4505 g = string_catn(g, smtp_code, 3);
4506 g = string_catn(g, US"-PRDR\r\n", 7);
4511 if ( accept_8bitmime
4512 && verify_check_host(&smtputf8_advertise_hosts) != FAIL)
4514 g = string_catn(g, smtp_code, 3);
4515 g = string_catn(g, US"-SMTPUTF8\r\n", 11);
4516 fl.smtputf8_advertised = TRUE;
4520 /* Finish off the multiline reply with one that is always available. */
4522 g = string_catn(g, smtp_code, 3);
4523 g = string_catn(g, US" HELP\r\n", 7);
4526 /* Terminate the string (for debug), write it, and note that HELO/EHLO
4530 if (tls_in.active.sock >= 0)
4531 (void)tls_write(NULL, g->s, g->ptr,
4532 # ifndef DISABLE_PIPE_CONNECT
4533 fl.pipe_connect_acceptable && pipeline_connect_sends());
4539 (void) fwrite(g->s, 1, g->ptr, smtp_out);
4545 (void) string_from_gstring(g);
4546 while ((cr = Ustrchr(g->s, '\r')) != NULL) /* lose CRs */
4547 memmove(cr, cr + 1, (g->ptr--) - (cr - g->s));
4548 debug_printf("SMTP>> %s", g->s);
4550 fl.helo_seen = TRUE;
4552 /* Reset the protocol and the state, abandoning any previous message. */
4554 (sender_host_address ? protocols : protocols_local)
4556 ? pextend + (sender_host_authenticated ? pauthed : 0)
4558 + (tls_in.active.sock >= 0 ? pcrpted : 0)
4560 cancel_cutthrough_connection(TRUE, US"sent EHLO response");
4561 reset_point = smtp_reset(reset_point);
4563 break; /* HELO/EHLO */
4566 /* The MAIL command requires an address as an operand. All we do
4567 here is to parse it for syntactic correctness. The form "<>" is
4568 a special case which converts into an empty string. The start/end
4569 pointers in the original are not used further for this address, as
4570 it is the canonical extracted address which is all that is kept. */
4574 smtp_mailcmd_count++; /* Count for limit and ratelimit */
4576 was_rej_mail = TRUE; /* Reset if accepted */
4577 env_mail_type_t * mail_args; /* Sanity check & validate args */
4580 if (fl.helo_required)
4582 smtp_printf("503 HELO or EHLO required\r\n", FALSE);
4583 log_write(0, LOG_MAIN|LOG_REJECT, "rejected MAIL from %s: no "
4584 "HELO/EHLO given", host_and_ident(FALSE));
4587 else if (mailmax < 0)
4588 mailmax = expand_mailmax(smtp_accept_max_per_connection);
4592 done = synprot_error(L_smtp_protocol_error, 503, NULL,
4593 US"sender already given");
4597 if (!*smtp_cmd_data)
4599 done = synprot_error(L_smtp_protocol_error, 501, NULL,
4600 US"MAIL must have an address operand");
4604 /* Check to see if the limit for messages per connection would be
4605 exceeded by accepting further messages. */
4607 if (mailmax > 0 && smtp_mailcmd_count > mailmax)
4609 smtp_printf("421 too many messages in this connection\r\n", FALSE);
4610 log_write(0, LOG_MAIN|LOG_REJECT, "rejected MAIL command %s: too many "
4611 "messages in one connection", host_and_ident(TRUE));
4615 /* Reset for start of message - even if this is going to fail, we
4616 obviously need to throw away any previous data. */
4618 cancel_cutthrough_connection(TRUE, US"MAIL received");
4619 reset_point = smtp_reset(reset_point);
4621 sender_data = recipient_data = NULL;
4623 /* Loop, checking for ESMTP additions to the MAIL FROM command. */
4625 if (fl.esmtp) for(;;)
4627 uschar *name, *value, *end;
4628 unsigned long int size;
4629 BOOL arg_error = FALSE;
4631 if (!extract_option(&name, &value)) break;
4633 for (mail_args = env_mail_type_list;
4634 mail_args->value != ENV_MAIL_OPT_NULL;
4637 if (strcmpic(name, mail_args->name) == 0)
4639 if (mail_args->need_value && strcmpic(value, US"") == 0)
4642 switch(mail_args->value)
4644 /* Handle SIZE= by reading the value. We don't do the check till later,
4645 in order to be able to log the sender address on failure. */
4646 case ENV_MAIL_OPT_SIZE:
4647 if (((size = Ustrtoul(value, &end, 10)), *end == 0))
4649 if ((size == ULONG_MAX && errno == ERANGE) || size > INT_MAX)
4651 message_size = (int)size;
4657 /* If this session was initiated with EHLO and accept_8bitmime is set,
4658 Exim will have indicated that it supports the BODY=8BITMIME option. In
4659 fact, it does not support this according to the RFCs, in that it does not
4660 take any special action for forwarding messages containing 8-bit
4661 characters. That is why accept_8bitmime is not the default setting, but
4662 some sites want the action that is provided. We recognize both "8BITMIME"
4663 and "7BIT" as body types, but take no action. */
4664 case ENV_MAIL_OPT_BODY:
4665 if (accept_8bitmime) {
4666 if (strcmpic(value, US"8BITMIME") == 0)
4668 else if (strcmpic(value, US"7BIT") == 0)
4673 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4674 US"invalid data for BODY");
4677 DEBUG(D_receive) debug_printf("8BITMIME: %d\n", body_8bitmime);
4683 /* Handle the two DSN options, but only if configured to do so (which
4684 will have caused "DSN" to be given in the EHLO response). The code itself
4685 is included only if configured in at build time. */
4687 case ENV_MAIL_OPT_RET:
4688 if (fl.dsn_advertised)
4690 /* Check if RET has already been set */
4693 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4694 US"RET can be specified once only");
4697 dsn_ret = strcmpic(value, US"HDRS") == 0
4699 : strcmpic(value, US"FULL") == 0
4702 DEBUG(D_receive) debug_printf("DSN_RET: %d\n", dsn_ret);
4703 /* Check for invalid invalid value, and exit with error */
4706 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4707 US"Value for RET is invalid");
4712 case ENV_MAIL_OPT_ENVID:
4713 if (fl.dsn_advertised)
4715 /* Check if the dsn envid has been already set */
4718 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4719 US"ENVID can be specified once only");
4722 dsn_envid = string_copy(value);
4723 DEBUG(D_receive) debug_printf("DSN_ENVID: %s\n", dsn_envid);
4727 /* Handle the AUTH extension. If the value given is not "<>" and either
4728 the ACL says "yes" or there is no ACL but the sending host is
4729 authenticated, we set it up as the authenticated sender. However, if the
4730 authenticator set a condition to be tested, we ignore AUTH on MAIL unless
4731 the condition is met. The value of AUTH is an xtext, which means that +,
4732 = and cntrl chars are coded in hex; however "<>" is unaffected by this
4734 case ENV_MAIL_OPT_AUTH:
4735 if (Ustrcmp(value, "<>") != 0)
4740 if (auth_xtextdecode(value, &authenticated_sender) < 0)
4742 /* Put back terminator overrides for error message */
4745 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4746 US"invalid data for AUTH");
4749 if (!acl_smtp_mailauth)
4751 ignore_msg = US"client not authenticated";
4752 rc = sender_host_authenticated ? OK : FAIL;
4756 ignore_msg = US"rejected by ACL";
4757 rc = acl_check(ACL_WHERE_MAILAUTH, NULL, acl_smtp_mailauth,
4758 &user_msg, &log_msg);
4764 if (authenticated_by == NULL ||
4765 authenticated_by->mail_auth_condition == NULL ||
4766 expand_check_condition(authenticated_by->mail_auth_condition,
4767 authenticated_by->name, US"authenticator"))
4768 break; /* Accept the AUTH */
4770 ignore_msg = US"server_mail_auth_condition failed";
4771 if (authenticated_id != NULL)
4772 ignore_msg = string_sprintf("%s: authenticated ID=\"%s\"",
4773 ignore_msg, authenticated_id);
4778 authenticated_sender = NULL;
4779 log_write(0, LOG_MAIN, "ignoring AUTH=%s from %s (%s)",
4780 value, host_and_ident(TRUE), ignore_msg);
4783 /* Should only get DEFER or ERROR here. Put back terminator
4784 overrides for error message */
4789 (void)smtp_handle_acl_fail(ACL_WHERE_MAILAUTH, rc, user_msg,
4796 #ifndef DISABLE_PRDR
4797 case ENV_MAIL_OPT_PRDR:
4799 prdr_requested = TRUE;
4804 case ENV_MAIL_OPT_UTF8:
4805 if (!fl.smtputf8_advertised)
4807 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4808 US"SMTPUTF8 used when not advertised");
4812 DEBUG(D_receive) debug_printf("smtputf8 requested\n");
4813 message_smtputf8 = allow_utf8_domains = TRUE;
4814 if (Ustrncmp(received_protocol, US"utf8", 4) != 0)
4816 int old_pool = store_pool;
4817 store_pool = POOL_PERM;
4818 received_protocol = string_sprintf("utf8%s", received_protocol);
4819 store_pool = old_pool;
4824 /* No valid option. Stick back the terminator characters and break
4825 the loop. Do the name-terminator second as extract_option sets
4826 value==name when it found no equal-sign.
4827 An error for a malformed address will occur. */
4828 case ENV_MAIL_OPT_NULL:
4836 /* Break out of for loop if switch() had bad argument or
4837 when start of the email address is reached */
4838 if (arg_error) break;
4841 /* If we have passed the threshold for rate limiting, apply the current
4842 delay, and update it for next time, provided this is a limited host. */
4844 if (smtp_mailcmd_count > smtp_rlm_threshold &&
4845 verify_check_host(&smtp_ratelimit_hosts) == OK)
4847 DEBUG(D_receive) debug_printf("rate limit MAIL: delay %.3g sec\n",
4848 smtp_delay_mail/1000.0);
4849 millisleep((int)smtp_delay_mail);
4850 smtp_delay_mail *= smtp_rlm_factor;
4851 if (smtp_delay_mail > (double)smtp_rlm_limit)
4852 smtp_delay_mail = (double)smtp_rlm_limit;
4855 /* Now extract the address, first applying any SMTP-time rewriting. The
4856 TRUE flag allows "<>" as a sender address. */
4858 raw_sender = rewrite_existflags & rewrite_smtp
4859 ? rewrite_one(smtp_cmd_data, rewrite_smtp, NULL, FALSE, US"",
4860 global_rewrite_rules)
4864 parse_extract_address(raw_sender, &errmess, &start, &end, &sender_domain,
4869 done = synprot_error(L_smtp_syntax_error, 501, smtp_cmd_data, errmess);
4873 sender_address = raw_sender;
4875 /* If there is a configured size limit for mail, check that this message
4876 doesn't exceed it. The check is postponed to this point so that the sender
4879 if (thismessage_size_limit > 0 && message_size > thismessage_size_limit)
4881 smtp_printf("552 Message size exceeds maximum permitted\r\n", FALSE);
4882 log_write(L_size_reject,
4883 LOG_MAIN|LOG_REJECT, "rejected MAIL FROM:<%s> %s: "
4884 "message too big: size%s=%d max=%d",
4886 host_and_ident(TRUE),
4887 (message_size == INT_MAX)? ">" : "",
4889 thismessage_size_limit);
4890 sender_address = NULL;
4894 /* Check there is enough space on the disk unless configured not to.
4895 When smtp_check_spool_space is set, the check is for thismessage_size_limit
4896 plus the current message - i.e. we accept the message only if it won't
4897 reduce the space below the threshold. Add 5000 to the size to allow for
4898 overheads such as the Received: line and storing of recipients, etc.
4899 By putting the check here, even when SIZE is not given, it allow VRFY
4900 and EXPN etc. to be used when space is short. */
4902 if (!receive_check_fs(
4903 smtp_check_spool_space && message_size >= 0
4904 ? message_size + 5000 : 0))
4906 smtp_printf("452 Space shortage, please try later\r\n", FALSE);
4907 sender_address = NULL;
4911 /* If sender_address is unqualified, reject it, unless this is a locally
4912 generated message, or the sending host or net is permitted to send
4913 unqualified addresses - typically local machines behaving as MUAs -
4914 in which case just qualify the address. The flag is set above at the start
4915 of the SMTP connection. */
4917 if (!sender_domain && *sender_address)
4918 if (f.allow_unqualified_sender)
4920 sender_domain = Ustrlen(sender_address) + 1;
4921 sender_address = rewrite_address_qualify(sender_address, FALSE);
4922 DEBUG(D_receive) debug_printf("unqualified address %s accepted\n",
4927 smtp_printf("501 %s: sender address must contain a domain\r\n", FALSE,
4929 log_write(L_smtp_syntax_error,
4930 LOG_MAIN|LOG_REJECT,
4931 "unqualified sender rejected: <%s> %s%s",
4933 host_and_ident(TRUE),
4935 sender_address = NULL;
4939 /* Apply an ACL check if one is defined, before responding. Afterwards,
4940 when pipelining is not advertised, do another sync check in case the ACL
4941 delayed and the client started sending in the meantime. */
4945 rc = acl_check(ACL_WHERE_MAIL, NULL, acl_smtp_mail, &user_msg, &log_msg);
4946 if (rc == OK && !f.smtp_in_pipelining_advertised && !check_sync())
4952 if (rc == OK || rc == DISCARD)
4954 BOOL more = pipeline_response();
4957 smtp_printf("%s%s%s", more, US"250 OK",
4958 #ifndef DISABLE_PRDR
4959 prdr_requested ? US", PRDR Requested" : US"",
4966 #ifndef DISABLE_PRDR
4968 user_msg = string_sprintf("%s%s", user_msg, US", PRDR Requested");
4970 smtp_user_msg(US"250", user_msg);
4972 smtp_delay_rcpt = smtp_rlr_base;
4973 f.recipients_discarded = (rc == DISCARD);
4974 was_rej_mail = FALSE;
4978 done = smtp_handle_acl_fail(ACL_WHERE_MAIL, rc, user_msg, log_msg);
4979 sender_address = NULL;
4984 /* The RCPT command requires an address as an operand. There may be any
4985 number of RCPT commands, specifying multiple recipients. We build them all
4986 into a data structure. The start/end values given by parse_extract_address
4987 are not used, as we keep only the extracted address. */
4992 was_rcpt = fl.rcpt_in_progress = TRUE;
4994 /* There must be a sender address; if the sender was rejected and
4995 pipelining was advertised, we assume the client was pipelining, and do not
4996 count this as a protocol error. Reset was_rej_mail so that further RCPTs
4997 get the same treatment. */
4999 if (sender_address == NULL)
5001 if (f.smtp_in_pipelining_advertised && last_was_rej_mail)
5003 smtp_printf("503 sender not yet given\r\n", FALSE);
5004 was_rej_mail = TRUE;
5008 done = synprot_error(L_smtp_protocol_error, 503, NULL,
5009 US"sender not yet given");
5010 was_rcpt = FALSE; /* Not a valid RCPT */
5016 /* Check for an operand */
5018 if (smtp_cmd_data[0] == 0)
5020 done = synprot_error(L_smtp_syntax_error, 501, NULL,
5021 US"RCPT must have an address operand");
5026 /* Set the DSN flags orcpt and dsn_flags from the session*/
5030 if (fl.esmtp) for(;;)
5032 uschar *name, *value;
5034 if (!extract_option(&name, &value))
5037 if (fl.dsn_advertised && strcmpic(name, US"ORCPT") == 0)
5039 /* Check whether orcpt has been already set */
5042 done = synprot_error(L_smtp_syntax_error, 501, NULL,
5043 US"ORCPT can be specified once only");
5046 orcpt = string_copy(value);
5047 DEBUG(D_receive) debug_printf("DSN orcpt: %s\n", orcpt);
5050 else if (fl.dsn_advertised && strcmpic(name, US"NOTIFY") == 0)
5052 /* Check if the notify flags have been already set */
5055 done = synprot_error(L_smtp_syntax_error, 501, NULL,
5056 US"NOTIFY can be specified once only");
5059 if (strcmpic(value, US"NEVER") == 0)
5060 dsn_flags |= rf_notify_never;
5067 while (*pp != 0 && *pp != ',') pp++;
5068 if (*pp == ',') *pp++ = 0;
5069 if (strcmpic(p, US"SUCCESS") == 0)
5071 DEBUG(D_receive) debug_printf("DSN: Setting notify success\n");
5072 dsn_flags |= rf_notify_success;
5074 else if (strcmpic(p, US"FAILURE") == 0)
5076 DEBUG(D_receive) debug_printf("DSN: Setting notify failure\n");
5077 dsn_flags |= rf_notify_failure;
5079 else if (strcmpic(p, US"DELAY") == 0)
5081 DEBUG(D_receive) debug_printf("DSN: Setting notify delay\n");
5082 dsn_flags |= rf_notify_delay;
5086 /* Catch any strange values */
5087 done = synprot_error(L_smtp_syntax_error, 501, NULL,
5088 US"Invalid value for NOTIFY parameter");
5093 DEBUG(D_receive) debug_printf("DSN Flags: %x\n", dsn_flags);
5097 /* Unknown option. Stick back the terminator characters and break
5098 the loop. An error for a malformed address will occur. */
5102 DEBUG(D_receive) debug_printf("Invalid RCPT option: %s : %s\n", name, value);
5109 /* Apply SMTP rewriting then extract the working address. Don't allow "<>"
5110 as a recipient address */
5112 recipient = rewrite_existflags & rewrite_smtp
5113 ? rewrite_one(smtp_cmd_data, rewrite_smtp, NULL, FALSE, US"",
5114 global_rewrite_rules)
5117 if (!(recipient = parse_extract_address(recipient, &errmess, &start, &end,
5118 &recipient_domain, FALSE)))
5120 done = synprot_error(L_smtp_syntax_error, 501, smtp_cmd_data, errmess);
5125 /* If the recipient address is unqualified, reject it, unless this is a
5126 locally generated message. However, unqualified addresses are permitted
5127 from a configured list of hosts and nets - typically when behaving as
5128 MUAs rather than MTAs. Sad that SMTP is used for both types of traffic,
5129 really. The flag is set at the start of the SMTP connection.
5131 RFC 1123 talks about supporting "the reserved mailbox postmaster"; I always
5132 assumed this meant "reserved local part", but the revision of RFC 821 and
5133 friends now makes it absolutely clear that it means *mailbox*. Consequently
5134 we must always qualify this address, regardless. */
5136 if (!recipient_domain)
5137 if (!(recipient_domain = qualify_recipient(&recipient, smtp_cmd_data,
5144 /* Check maximum allowed */
5146 if (rcpt_count > recipients_max && recipients_max > 0)
5148 if (recipients_max_reject)
5151 smtp_printf("552 too many recipients\r\n", FALSE);
5153 log_write(0, LOG_MAIN|LOG_REJECT, "too many recipients: message "
5154 "rejected: sender=<%s> %s", sender_address, host_and_ident(TRUE));
5159 smtp_printf("452 too many recipients\r\n", FALSE);
5161 log_write(0, LOG_MAIN|LOG_REJECT, "too many recipients: excess "
5162 "temporarily rejected: sender=<%s> %s", sender_address,
5163 host_and_ident(TRUE));
5170 /* If we have passed the threshold for rate limiting, apply the current
5171 delay, and update it for next time, provided this is a limited host. */
5173 if (rcpt_count > smtp_rlr_threshold &&
5174 verify_check_host(&smtp_ratelimit_hosts) == OK)
5176 DEBUG(D_receive) debug_printf("rate limit RCPT: delay %.3g sec\n",
5177 smtp_delay_rcpt/1000.0);
5178 millisleep((int)smtp_delay_rcpt);
5179 smtp_delay_rcpt *= smtp_rlr_factor;
5180 if (smtp_delay_rcpt > (double)smtp_rlr_limit)
5181 smtp_delay_rcpt = (double)smtp_rlr_limit;
5184 /* If the MAIL ACL discarded all the recipients, we bypass ACL checking
5185 for them. Otherwise, check the access control list for this recipient. As
5186 there may be a delay in this, re-check for a synchronization error
5187 afterwards, unless pipelining was advertised. */
5189 if (f.recipients_discarded)
5192 if ( (rc = acl_check(ACL_WHERE_RCPT, recipient, acl_smtp_rcpt, &user_msg,
5194 && !f.smtp_in_pipelining_advertised && !check_sync())
5197 /* The ACL was happy */
5201 BOOL more = pipeline_response();
5204 smtp_user_msg(US"250", user_msg);
5206 smtp_printf("250 Accepted\r\n", more);
5207 receive_add_recipient(recipient, -1);
5209 /* Set the dsn flags in the recipients_list */
5210 recipients_list[recipients_count-1].orcpt = orcpt;
5211 recipients_list[recipients_count-1].dsn_flags = dsn_flags;
5213 /* DEBUG(D_receive) debug_printf("DSN: orcpt: %s flags: %d\n",
5214 recipients_list[recipients_count-1].orcpt,
5215 recipients_list[recipients_count-1].dsn_flags); */
5218 /* The recipient was discarded */
5220 else if (rc == DISCARD)
5223 smtp_user_msg(US"250", user_msg);
5225 smtp_printf("250 Accepted\r\n", FALSE);
5228 log_write(0, LOG_MAIN|LOG_REJECT, "%s F=<%s> RCPT %s: "
5229 "discarded by %s ACL%s%s", host_and_ident(TRUE),
5230 sender_address_unrewritten ? sender_address_unrewritten : sender_address,
5231 smtp_cmd_argument, f.recipients_discarded ? "MAIL" : "RCPT",
5232 log_msg ? US": " : US"", log_msg ? log_msg : US"");
5235 /* Either the ACL failed the address, or it was deferred. */
5239 if (rc == FAIL) rcpt_fail_count++; else rcpt_defer_count++;
5240 done = smtp_handle_acl_fail(ACL_WHERE_RCPT, rc, user_msg, log_msg);
5245 /* The DATA command is legal only if it follows successful MAIL FROM
5246 and RCPT TO commands. However, if pipelining is advertised, a bad DATA is
5247 not counted as a protocol error if it follows RCPT (which must have been
5248 rejected if there are no recipients.) This function is complete when a
5249 valid DATA command is encountered.
5251 Note concerning the code used: RFC 2821 says this:
5253 - If there was no MAIL, or no RCPT, command, or all such commands
5254 were rejected, the server MAY return a "command out of sequence"
5255 (503) or "no valid recipients" (554) reply in response to the
5258 The example in the pipelining RFC 2920 uses 554, but I use 503 here
5259 because it is the same whether pipelining is in use or not.
5261 If all the RCPT commands that precede DATA provoked the same error message
5262 (often indicating some kind of system error), it is helpful to include it
5263 with the DATA rejection (an idea suggested by Tony Finch). */
5270 if (chunking_state != CHUNKING_OFFERED)
5272 done = synprot_error(L_smtp_protocol_error, 503, NULL,
5273 US"BDAT command used when CHUNKING not advertised");
5277 /* grab size, endmarker */
5279 if (sscanf(CS smtp_cmd_data, "%u %n", &chunking_datasize, &n) < 1)
5281 done = synprot_error(L_smtp_protocol_error, 501, NULL,
5282 US"missing size for BDAT command");
5285 chunking_state = strcmpic(smtp_cmd_data+n, US"LAST") == 0
5286 ? CHUNKING_LAST : CHUNKING_ACTIVE;
5287 chunking_data_left = chunking_datasize;
5288 DEBUG(D_receive) debug_printf("chunking state %d, %d bytes\n",
5289 (int)chunking_state, chunking_data_left);
5291 /* push the current receive_* function on the "stack", and
5292 replace them by bdat_getc(), which in turn will use the lwr_receive_*
5293 functions to do the dirty work. */
5294 lwr_receive_getc = receive_getc;
5295 lwr_receive_getbuf = receive_getbuf;
5296 lwr_receive_ungetc = receive_ungetc;
5298 receive_getc = bdat_getc;
5299 receive_ungetc = bdat_ungetc;
5310 DATA_BDAT: /* Common code for DATA and BDAT */
5311 #ifndef DISABLE_PIPE_CONNECT
5312 fl.pipe_connect_acceptable = FALSE;
5314 if (!discarded && recipients_count <= 0)
5316 if (fl.rcpt_smtp_response_same && rcpt_smtp_response != NULL)
5318 uschar *code = US"503";
5319 int len = Ustrlen(rcpt_smtp_response);
5320 smtp_respond(code, 3, FALSE, US"All RCPT commands were rejected with "
5322 /* Responses from smtp_printf() will have \r\n on the end */
5323 if (len > 2 && rcpt_smtp_response[len-2] == '\r')
5324 rcpt_smtp_response[len-2] = 0;
5325 smtp_respond(code, 3, FALSE, rcpt_smtp_response);
5327 if (f.smtp_in_pipelining_advertised && last_was_rcpt)
5328 smtp_printf("503 Valid RCPT command must precede %s\r\n", FALSE,
5329 smtp_names[smtp_connection_had[SMTP_HBUFF_PREV(smtp_ch_index)]]);
5331 done = synprot_error(L_smtp_protocol_error, 503, NULL,
5332 smtp_connection_had[SMTP_HBUFF_PREV(smtp_ch_index)] == SCH_DATA
5333 ? US"valid RCPT command must precede DATA"
5334 : US"valid RCPT command must precede BDAT");
5336 if (chunking_state > CHUNKING_OFFERED)
5341 if (toomany && recipients_max_reject)
5343 sender_address = NULL; /* This will allow a new MAIL without RSET */
5344 sender_address_unrewritten = NULL;
5345 smtp_printf("554 Too many recipients\r\n", FALSE);
5349 if (chunking_state > CHUNKING_OFFERED)
5350 rc = OK; /* No predata ACL or go-ahead output for BDAT */
5353 /* If there is an ACL, re-check the synchronization afterwards, since the
5354 ACL may have delayed. To handle cutthrough delivery enforce a dummy call
5355 to get the DATA command sent. */
5357 if (acl_smtp_predata == NULL && cutthrough.cctx.sock < 0)
5361 uschar * acl = acl_smtp_predata ? acl_smtp_predata : US"accept";
5362 f.enable_dollar_recipients = TRUE;
5363 rc = acl_check(ACL_WHERE_PREDATA, NULL, acl, &user_msg,
5365 f.enable_dollar_recipients = FALSE;
5366 if (rc == OK && !check_sync())
5370 { /* Either the ACL failed the address, or it was deferred. */
5371 done = smtp_handle_acl_fail(ACL_WHERE_PREDATA, rc, user_msg, log_msg);
5377 smtp_user_msg(US"354", user_msg);
5380 "354 Enter message, ending with \".\" on a line by itself\r\n", FALSE);
5384 if (smtp_in) /* all ACKs needed to ramp window up for bulk data */
5385 (void) setsockopt(fileno(smtp_in), IPPROTO_TCP, TCP_QUICKACK,
5386 US &on, sizeof(on));
5389 message_ended = END_NOTENDED; /* Indicate in middle of data */
5400 if (!(address = parse_extract_address(smtp_cmd_data, &errmess,
5401 &start, &end, &recipient_domain, FALSE)))
5403 smtp_printf("501 %s\r\n", FALSE, errmess);
5407 if (!recipient_domain)
5408 if (!(recipient_domain = qualify_recipient(&address, smtp_cmd_data,
5412 if ((rc = acl_check(ACL_WHERE_VRFY, address, acl_smtp_vrfy,
5413 &user_msg, &log_msg)) != OK)
5414 done = smtp_handle_acl_fail(ACL_WHERE_VRFY, rc, user_msg, log_msg);
5418 address_item * addr = deliver_make_addr(address, FALSE);
5420 switch(verify_address(addr, NULL, vopt_is_recipient | vopt_qualify, -1,
5421 -1, -1, NULL, NULL, NULL))
5424 s = string_sprintf("250 <%s> is deliverable", address);
5428 s = (addr->user_message != NULL)?
5429 string_sprintf("451 <%s> %s", address, addr->user_message) :
5430 string_sprintf("451 Cannot resolve <%s> at this time", address);
5434 s = (addr->user_message != NULL)?
5435 string_sprintf("550 <%s> %s", address, addr->user_message) :
5436 string_sprintf("550 <%s> is not deliverable", address);
5437 log_write(0, LOG_MAIN, "VRFY failed for %s %s",
5438 smtp_cmd_argument, host_and_ident(TRUE));
5442 smtp_printf("%s\r\n", FALSE, s);
5450 rc = acl_check(ACL_WHERE_EXPN, NULL, acl_smtp_expn, &user_msg, &log_msg);
5452 done = smtp_handle_acl_fail(ACL_WHERE_EXPN, rc, user_msg, log_msg);
5455 BOOL save_log_testing_mode = f.log_testing_mode;
5456 f.address_test_mode = f.log_testing_mode = TRUE;
5457 (void) verify_address(deliver_make_addr(smtp_cmd_data, FALSE),
5458 smtp_out, vopt_is_recipient | vopt_qualify | vopt_expn, -1, -1, -1,
5460 f.address_test_mode = FALSE;
5461 f.log_testing_mode = save_log_testing_mode; /* true for -bh */
5470 if (!fl.tls_advertised)
5472 done = synprot_error(L_smtp_protocol_error, 503, NULL,
5473 US"STARTTLS command used when not advertised");
5477 /* Apply an ACL check if one is defined */
5479 if ( acl_smtp_starttls
5480 && (rc = acl_check(ACL_WHERE_STARTTLS, NULL, acl_smtp_starttls,
5481 &user_msg, &log_msg)) != OK
5484 done = smtp_handle_acl_fail(ACL_WHERE_STARTTLS, rc, user_msg, log_msg);
5488 /* RFC 2487 is not clear on when this command may be sent, though it
5489 does state that all information previously obtained from the client
5490 must be discarded if a TLS session is started. It seems reasonable to
5491 do an implied RSET when STARTTLS is received. */
5493 incomplete_transaction_log(US"STARTTLS");
5494 cancel_cutthrough_connection(TRUE, US"STARTTLS received");
5495 reset_point = smtp_reset(reset_point);
5497 cmd_list[CMD_LIST_STARTTLS].is_mail_cmd = FALSE;
5499 /* There's an attack where more data is read in past the STARTTLS command
5500 before TLS is negotiated, then assumed to be part of the secure session
5501 when used afterwards; we use segregated input buffers, so are not
5502 vulnerable, but we want to note when it happens and, for sheer paranoia,
5503 ensure that the buffer is "wiped".
5504 Pipelining sync checks will normally have protected us too, unless disabled
5505 by configuration. */
5507 if (receive_smtp_buffered())
5510 debug_printf("Non-empty input buffer after STARTTLS; naive attack?\n");
5511 if (tls_in.active.sock < 0)
5512 smtp_inend = smtp_inptr = smtp_inbuffer;
5513 /* and if TLS is already active, tls_server_start() should fail */
5516 /* There is nothing we value in the input buffer and if TLS is successfully
5517 negotiated, we won't use this buffer again; if TLS fails, we'll just read
5518 fresh content into it. The buffer contains arbitrary content from an
5519 untrusted remote source; eg: NOOP <shellcode>\r\nSTARTTLS\r\n
5520 It seems safest to just wipe away the content rather than leave it as a
5521 target to jump to. */
5523 memset(smtp_inbuffer, 0, IN_BUFFER_SIZE);
5525 /* Attempt to start up a TLS session, and if successful, discard all
5526 knowledge that was obtained previously. At least, that's what the RFC says,
5527 and that's what happens by default. However, in order to work round YAEB,
5528 there is an option to remember the esmtp state. Sigh.
5530 We must allow for an extra EHLO command and an extra AUTH command after
5531 STARTTLS that don't add to the nonmail command count. */
5534 if ((rc = tls_server_start(&s)) == OK)
5536 if (!tls_remember_esmtp)
5537 fl.helo_seen = fl.esmtp = fl.auth_advertised = f.smtp_in_pipelining_advertised = FALSE;
5538 cmd_list[CMD_LIST_EHLO].is_mail_cmd = TRUE;
5539 cmd_list[CMD_LIST_AUTH].is_mail_cmd = TRUE;
5540 cmd_list[CMD_LIST_TLS_AUTH].is_mail_cmd = TRUE;
5541 if (sender_helo_name)
5543 sender_helo_name = NULL;
5544 host_build_sender_fullhost(); /* Rebuild */
5545 set_process_info("handling incoming TLS connection from %s",
5546 host_and_ident(FALSE));
5549 (sender_host_address ? protocols : protocols_local)
5551 ? pextend + (sender_host_authenticated ? pauthed : 0)
5553 + (tls_in.active.sock >= 0 ? pcrpted : 0)
5556 sender_host_auth_pubname = sender_host_authenticated = NULL;
5557 authenticated_id = NULL;
5558 sync_cmd_limit = NON_SYNC_CMD_NON_PIPELINING;
5559 DEBUG(D_tls) debug_printf("TLS active\n");
5560 break; /* Successful STARTTLS */
5563 (void) smtp_log_tls_fail(s);
5565 /* Some local configuration problem was discovered before actually trying
5566 to do a TLS handshake; give a temporary error. */
5570 smtp_printf("454 TLS currently unavailable\r\n", FALSE);
5574 /* Hard failure. Reject everything except QUIT or closed connection. One
5575 cause for failure is a nested STARTTLS, in which case tls_in.active remains
5576 set, but we must still reject all incoming commands. Another is a handshake
5577 failure - and there may some encrypted data still in the pipe to us, which we
5578 see as garbage commands. */
5580 DEBUG(D_tls) debug_printf("TLS failed to start\n");
5581 while (done <= 0) switch(smtp_read_command(FALSE, GETC_BUFFER_UNLIMITED))
5584 log_write(L_smtp_connection, LOG_MAIN, "%s closed by EOF",
5585 smtp_get_connection_info());
5586 smtp_notquit_exit(US"tls-failed", NULL, NULL);
5590 /* It is perhaps arguable as to which exit ACL should be called here,
5591 but as it is probably a situation that almost never arises, it
5592 probably doesn't matter. We choose to call the real QUIT ACL, which in
5593 some sense is perhaps "right". */
5596 f.smtp_in_quit = TRUE;
5599 && ((rc = acl_check(ACL_WHERE_QUIT, NULL, acl_smtp_quit, &user_msg,
5600 &log_msg)) == ERROR))
5601 log_write(0, LOG_MAIN|LOG_PANIC, "ACL for QUIT returned ERROR: %s",
5604 smtp_respond(US"221", 3, TRUE, user_msg);
5606 smtp_printf("221 %s closing connection\r\n", FALSE, smtp_active_hostname);
5607 log_write(L_smtp_connection, LOG_MAIN, "%s closed by QUIT",
5608 smtp_get_connection_info());
5613 smtp_printf("554 Security failure\r\n", FALSE);
5616 tls_close(NULL, TLS_SHUTDOWN_NOWAIT);
5621 /* The ACL for QUIT is provided for gathering statistical information or
5622 similar; it does not affect the response code, but it can supply a custom
5626 smtp_quit_handler(&user_msg, &log_msg);
5632 smtp_rset_handler();
5633 cancel_cutthrough_connection(TRUE, US"RSET received");
5634 reset_point = smtp_reset(reset_point);
5641 smtp_printf("250 OK\r\n", FALSE);
5645 /* Show ETRN/EXPN/VRFY if there's an ACL for checking hosts; if actually
5646 used, a check will be done for permitted hosts. Show STARTTLS only if not
5647 already in a TLS session and if it would be advertised in the EHLO
5652 smtp_printf("214-Commands supported:\r\n", TRUE);
5656 Ustrcat(buffer, US" AUTH");
5658 if (tls_in.active.sock < 0 &&
5659 verify_check_host(&tls_advertise_hosts) != FAIL)
5660 Ustrcat(buffer, US" STARTTLS");
5662 Ustrcat(buffer, US" HELO EHLO MAIL RCPT DATA BDAT");
5663 Ustrcat(buffer, US" NOOP QUIT RSET HELP");
5664 if (acl_smtp_etrn) Ustrcat(buffer, US" ETRN");
5665 if (acl_smtp_expn) Ustrcat(buffer, US" EXPN");
5666 if (acl_smtp_vrfy) Ustrcat(buffer, US" VRFY");
5667 smtp_printf("214%s\r\n", FALSE, buffer);
5673 incomplete_transaction_log(US"connection lost");
5674 smtp_notquit_exit(US"connection-lost", US"421",
5675 US"%s lost input connection", smtp_active_hostname);
5677 /* Don't log by default unless in the middle of a message, as some mailers
5678 just drop the call rather than sending QUIT, and it clutters up the logs.
5681 if (sender_address || recipients_count > 0)
5682 log_write(L_lost_incoming_connection, LOG_MAIN,
5683 "unexpected %s while reading SMTP command from %s%s%s D=%s",
5684 f.sender_host_unknown ? "EOF" : "disconnection",
5685 f.tcp_in_fastopen_logged
5688 ? f.tcp_in_fastopen_data ? US"TFO* " : US"TFO "
5690 host_and_ident(FALSE), smtp_read_error,
5691 string_timesince(&smtp_connection_start)
5695 log_write(L_smtp_connection, LOG_MAIN, "%s %slost%s D=%s",
5696 smtp_get_connection_info(),
5697 f.tcp_in_fastopen && !f.tcp_in_fastopen_logged ? US"TFO " : US"",
5699 string_timesince(&smtp_connection_start)
5710 done = synprot_error(L_smtp_protocol_error, 503, NULL,
5711 US"ETRN is not permitted inside a transaction");
5715 log_write(L_etrn, LOG_MAIN, "ETRN %s received from %s", smtp_cmd_argument,
5716 host_and_ident(FALSE));
5718 if ((rc = acl_check(ACL_WHERE_ETRN, NULL, acl_smtp_etrn,
5719 &user_msg, &log_msg)) != OK)
5721 done = smtp_handle_acl_fail(ACL_WHERE_ETRN, rc, user_msg, log_msg);
5725 /* Compute the serialization key for this command. */
5727 etrn_serialize_key = string_sprintf("etrn-%s\n", smtp_cmd_data);
5729 /* If a command has been specified for running as a result of ETRN, we
5730 permit any argument to ETRN. If not, only the # standard form is permitted,
5731 since that is strictly the only kind of ETRN that can be implemented
5732 according to the RFC. */
5734 if (smtp_etrn_command)
5738 etrn_command = smtp_etrn_command;
5739 deliver_domain = smtp_cmd_data;
5740 rc = transport_set_up_command(&argv, smtp_etrn_command, TRUE, 0, NULL,
5741 US"ETRN processing", &error);
5742 deliver_domain = NULL;
5745 log_write(0, LOG_MAIN|LOG_PANIC, "failed to set up ETRN command: %s",
5747 smtp_printf("458 Internal failure\r\n", FALSE);
5752 /* Else set up to call Exim with the -R option. */
5756 if (*smtp_cmd_data++ != '#')
5758 done = synprot_error(L_smtp_syntax_error, 501, NULL,
5759 US"argument must begin with #");
5762 etrn_command = US"exim -R";
5763 argv = CUSS child_exec_exim(CEE_RETURN_ARGV, TRUE, NULL, TRUE,
5764 *queue_name ? 4 : 2,
5765 US"-R", smtp_cmd_data,
5766 US"-MCG", queue_name);
5769 /* If we are host-testing, don't actually do anything. */
5775 debug_printf("ETRN command is: %s\n", etrn_command);
5776 debug_printf("ETRN command execution skipped\n");
5778 if (user_msg == NULL) smtp_printf("250 OK\r\n", FALSE);
5779 else smtp_user_msg(US"250", user_msg);
5784 /* If ETRN queue runs are to be serialized, check the database to
5785 ensure one isn't already running. */
5787 if (smtp_etrn_serialize && !enq_start(etrn_serialize_key, 1))
5789 smtp_printf("458 Already processing %s\r\n", FALSE, smtp_cmd_data);
5793 /* Fork a child process and run the command. We don't want to have to
5794 wait for the process at any point, so set SIGCHLD to SIG_IGN before
5795 forking. It should be set that way anyway for external incoming SMTP,
5796 but we save and restore to be tidy. If serialization is required, we
5797 actually run the command in yet another process, so we can wait for it
5798 to complete and then remove the serialization lock. */
5800 oldsignal = signal(SIGCHLD, SIG_IGN);
5802 if ((pid = exim_fork(US"etrn-command")) == 0)
5804 smtp_input = FALSE; /* This process is not associated with the */
5805 (void)fclose(smtp_in); /* SMTP call any more. */
5806 (void)fclose(smtp_out);
5808 signal(SIGCHLD, SIG_DFL); /* Want to catch child */
5810 /* If not serializing, do the exec right away. Otherwise, fork down
5811 into another process. */
5813 if ( !smtp_etrn_serialize
5814 || (pid = exim_fork(US"etrn-serialised-command")) == 0)
5816 DEBUG(D_exec) debug_print_argv(argv);
5817 exim_nullstd(); /* Ensure std{in,out,err} exist */
5818 execv(CS argv[0], (char *const *)argv);
5819 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "exec of \"%s\" (ETRN) failed: %s",
5820 etrn_command, strerror(errno));
5821 _exit(EXIT_FAILURE); /* paranoia */
5824 /* Obey this if smtp_serialize and the 2nd fork yielded non-zero. That
5825 is, we are in the first subprocess, after forking again. All we can do
5826 for a failing fork is to log it. Otherwise, wait for the 2nd process to
5827 complete, before removing the serialization. */
5830 log_write(0, LOG_MAIN|LOG_PANIC, "2nd fork for serialized ETRN "
5831 "failed: %s", strerror(errno));
5835 DEBUG(D_any) debug_printf("waiting for serialized ETRN process %d\n",
5837 (void)wait(&status);
5838 DEBUG(D_any) debug_printf("serialized ETRN process %d ended\n",
5842 enq_end(etrn_serialize_key);
5843 exim_underbar_exit(EXIT_SUCCESS);
5846 /* Back in the top level SMTP process. Check that we started a subprocess
5847 and restore the signal state. */
5851 log_write(0, LOG_MAIN|LOG_PANIC, "fork of process for ETRN failed: %s",
5853 smtp_printf("458 Unable to fork process\r\n", FALSE);
5854 if (smtp_etrn_serialize) enq_end(etrn_serialize_key);
5858 smtp_printf("250 OK\r\n", FALSE);
5860 smtp_user_msg(US"250", user_msg);
5862 signal(SIGCHLD, oldsignal);
5867 done = synprot_error(L_smtp_syntax_error, 501, NULL,
5868 US"unexpected argument data");
5872 /* This currently happens only for NULLs, but could be extended. */
5875 done = synprot_error(L_smtp_syntax_error, 0, NULL, /* Just logs */
5876 US"NUL character(s) present (shown as '?')");
5877 smtp_printf("501 NUL characters are not allowed in SMTP commands\r\n",
5884 if (smtp_inend >= smtp_inbuffer + IN_BUFFER_SIZE)
5885 smtp_inend = smtp_inbuffer + IN_BUFFER_SIZE - 1;
5886 c = smtp_inend - smtp_inptr;
5887 if (c > 150) c = 150; /* limit logged amount */
5889 incomplete_transaction_log(US"sync failure");
5890 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP protocol synchronization error "
5891 "(next input sent too soon: pipelining was%s advertised): "
5892 "rejected \"%s\" %s next input=\"%s\"",
5893 f.smtp_in_pipelining_advertised ? "" : " not",
5894 smtp_cmd_buffer, host_and_ident(TRUE),
5895 string_printing(smtp_inptr));
5896 smtp_notquit_exit(US"synchronization-error", US"554",
5897 US"SMTP synchronization error");
5898 done = 1; /* Pretend eof - drops connection */
5902 case TOO_MANY_NONMAIL_CMD:
5903 s = smtp_cmd_buffer;
5904 while (*s != 0 && !isspace(*s)) s++;
5905 incomplete_transaction_log(US"too many non-mail commands");
5906 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
5907 "nonmail commands (last was \"%.*s\")", host_and_ident(FALSE),
5908 (int)(s - smtp_cmd_buffer), smtp_cmd_buffer);
5909 smtp_notquit_exit(US"bad-commands", US"554", US"Too many nonmail commands");
5910 done = 1; /* Pretend eof - drops connection */
5913 #ifdef SUPPORT_PROXY
5914 case PROXY_FAIL_IGNORE_CMD:
5915 smtp_printf("503 Command refused, required Proxy negotiation failed\r\n", FALSE);
5920 if (unknown_command_count++ >= smtp_max_unknown_commands)
5922 log_write(L_smtp_syntax_error, LOG_MAIN,
5923 "SMTP syntax error in \"%s\" %s %s",
5924 string_printing(smtp_cmd_buffer), host_and_ident(TRUE),
5925 US"unrecognized command");
5926 incomplete_transaction_log(US"unrecognized command");
5927 smtp_notquit_exit(US"bad-commands", US"500",
5928 US"Too many unrecognized commands");
5930 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
5931 "unrecognized commands (last was \"%s\")", host_and_ident(FALSE),
5932 string_printing(smtp_cmd_buffer));
5935 done = synprot_error(L_smtp_syntax_error, 500, NULL,
5936 US"unrecognized command");
5940 /* This label is used by goto's inside loops that want to break out to
5941 the end of the command-processing loop. */
5944 last_was_rej_mail = was_rej_mail; /* Remember some last commands for */
5945 last_was_rcpt = was_rcpt; /* protocol error handling */
5949 return done - 2; /* Convert yield values */
5955 authres_smtpauth(gstring * g)
5957 if (!sender_host_authenticated)
5960 g = string_append(g, 2, US";\n\tauth=pass (", sender_host_auth_pubname);
5962 if (Ustrcmp(sender_host_auth_pubname, "tls") == 0)
5963 g = authenticated_id
5964 ? string_append(g, 2, US") x509.auth=", authenticated_id)
5965 : string_cat(g, US") reason=x509.auth");
5967 g = authenticated_id
5968 ? string_append(g, 2, US") smtp.auth=", authenticated_id)
5969 : string_cat(g, US", no id saved)");
5971 if (authenticated_sender)
5972 g = string_append(g, 2, US" smtp.mailfrom=", authenticated_sender);
5980 /* End of smtp_in.c */