1 /*************************************************
2 * Exim - an Internet mail transport agent *
3 *************************************************/
5 /* Copyright (c) University of Cambridge 1995 - 2018 */
6 /* Copyright (c) The Exim Maintainers 2020 - 2021 */
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_verify_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_verify_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)
351 if (tls_in.active.sock >= 0)
352 return !tls_could_read();
355 if (smtp_inptr < smtp_inend)
358 fd = fileno(smtp_in);
359 rc = poll_one_fd(fd, POLLIN, 0);
361 if (rc <= 0) return TRUE; /* Not ready to read */
362 rc = smtp_getc(GETC_BUFFER_UNLIMITED);
363 if (rc < 0) return TRUE; /* End of file or error */
372 if (!smtp_enforce_sync || !sender_host_address || f.sender_host_notsocket)
375 return wouldblock_reading();
379 /* If there's input waiting (and we're doing pipelineing) then we can pipeline
380 a reponse with the one following. */
383 pipeline_response(void)
385 if ( !smtp_enforce_sync || !sender_host_address
386 || f.sender_host_notsocket || !f.smtp_in_pipelining_advertised)
389 if (wouldblock_reading()) return FALSE;
390 f.smtp_in_pipelining_used = TRUE;
395 #ifndef DISABLE_PIPE_CONNECT
397 pipeline_connect_sends(void)
399 if (!sender_host_address || f.sender_host_notsocket || !fl.pipe_connect_acceptable)
402 if (wouldblock_reading()) return FALSE;
403 f.smtp_in_early_pipe_used = TRUE;
408 /*************************************************
409 * Log incomplete transactions *
410 *************************************************/
412 /* This function is called after a transaction has been aborted by RSET, QUIT,
413 connection drops or other errors. It logs the envelope information received
414 so far in order to preserve address verification attempts.
416 Argument: string to indicate what aborted the transaction
421 incomplete_transaction_log(uschar *what)
423 if (!sender_address /* No transaction in progress */
424 || !LOGGING(smtp_incomplete_transaction))
427 /* Build list of recipients for logging */
429 if (recipients_count > 0)
431 raw_recipients = store_get(recipients_count * sizeof(uschar *), FALSE);
432 for (int i = 0; i < recipients_count; i++)
433 raw_recipients[i] = recipients_list[i].address;
434 raw_recipients_count = recipients_count;
437 log_write(L_smtp_incomplete_transaction, LOG_MAIN|LOG_SENDER|LOG_RECIPIENTS,
438 "%s incomplete transaction (%s)", host_and_ident(TRUE), what);
445 smtp_command_timeout_exit(void)
447 log_write(L_lost_incoming_connection,
448 LOG_MAIN, "SMTP command timeout on%s connection from %s",
449 tls_in.active.sock >= 0 ? " TLS" : "", host_and_ident(FALSE));
450 if (smtp_batched_input)
451 moan_smtp_batch(NULL, "421 SMTP command timeout"); /* Does not return */
452 smtp_notquit_exit(US"command-timeout", US"421",
453 US"%s: SMTP command timeout - closing connection",
454 smtp_active_hostname);
455 exim_exit(EXIT_FAILURE);
459 smtp_command_sigterm_exit(void)
461 log_write(0, LOG_MAIN, "%s closed after SIGTERM", smtp_get_connection_info());
462 if (smtp_batched_input)
463 moan_smtp_batch(NULL, "421 SIGTERM received"); /* Does not return */
464 smtp_notquit_exit(US"signal-exit", US"421",
465 US"%s: Service not available - closing connection", smtp_active_hostname);
466 exim_exit(EXIT_FAILURE);
470 smtp_data_timeout_exit(void)
472 log_write(L_lost_incoming_connection,
473 LOG_MAIN, "SMTP data timeout (message abandoned) on connection from %s F=<%s>",
474 sender_fullhost ? sender_fullhost : US"local process", sender_address);
475 receive_bomb_out(US"data-timeout", US"SMTP incoming data timeout");
476 /* Does not return */
480 smtp_data_sigint_exit(void)
482 log_write(0, LOG_MAIN, "%s closed after %s",
483 smtp_get_connection_info(), had_data_sigint == SIGTERM ? "SIGTERM":"SIGINT");
484 receive_bomb_out(US"signal-exit",
485 US"Service not available - SIGTERM or SIGINT received");
486 /* Does not return */
491 /* Refill the buffer, and notify DKIM verification code.
492 Return false for error or EOF.
496 smtp_refill(unsigned lim)
499 if (!smtp_out) return FALSE;
501 if (smtp_receive_timeout > 0) ALARM(smtp_receive_timeout);
503 /* Limit amount read, so non-message data is not fed to DKIM.
504 Take care to not touch the safety NUL at the end of the buffer. */
506 rc = read(fileno(smtp_in), smtp_inbuffer, MIN(IN_BUFFER_SIZE-1, lim));
508 if (smtp_receive_timeout > 0) ALARM_CLR(0);
511 /* Must put the error text in fixed store, because this might be during
512 header reading, where it releases unused store above the header. */
515 if (had_command_timeout) /* set by signal handler */
516 smtp_command_timeout_exit(); /* does not return */
517 if (had_command_sigterm)
518 smtp_command_sigterm_exit();
519 if (had_data_timeout)
520 smtp_data_timeout_exit();
522 smtp_data_sigint_exit();
524 smtp_had_error = save_errno;
525 smtp_read_error = string_copy_perm(
526 string_sprintf(" (error: %s)", strerror(save_errno)), FALSE);
533 dkim_exim_verify_feed(smtp_inbuffer, rc);
535 smtp_inend = smtp_inbuffer + rc;
536 smtp_inptr = smtp_inbuffer;
540 /*************************************************
541 * SMTP version of getc() *
542 *************************************************/
544 /* This gets the next byte from the SMTP input buffer. If the buffer is empty,
545 it flushes the output, and refills the buffer, with a timeout. The signal
546 handler is set appropriately by the calling function. This function is not used
547 after a connection has negotiated itself into an TLS/SSL state.
549 Arguments: lim Maximum amount to read/buffer
550 Returns: the next character or EOF
554 smtp_getc(unsigned lim)
556 if (smtp_inptr >= smtp_inend)
557 if (!smtp_refill(lim))
559 return *smtp_inptr++;
565 return smtp_inptr < smtp_inend;
569 smtp_getbuf(unsigned * len)
574 if (smtp_inptr >= smtp_inend)
575 if (!smtp_refill(*len))
576 { *len = 0; return NULL; }
578 if ((size = smtp_inend - smtp_inptr) > *len) size = *len;
586 smtp_get_cache(unsigned lim)
589 int n = smtp_inend - smtp_inptr;
593 dkim_exim_verify_feed(smtp_inptr, n);
598 /* Forward declarations */
599 static inline void bdat_push_receive_functions(void);
600 static inline void bdat_pop_receive_functions(void);
603 /* Get a byte from the smtp input, in CHUNKING mode. Handle ack of the
604 previous BDAT chunk and getting new ones when we run out. Uses the
605 underlying smtp_getc or tls_getc both for that and for getting the
606 (buffered) data byte. EOD signals (an expected) no further data.
607 ERR signals a protocol error, and EOF a closed input stream.
609 Called from read_bdat_smtp() in receive.c for the message body, but also
610 by the headers read loop in receive_msg(); manipulates chunking_state
611 to handle the BDAT command/response.
612 Placed here due to the correlation with the above smtp_getc(), which it wraps,
613 and also by the need to do smtp command/response handling.
615 Arguments: lim (ignored)
616 Returns: the next character or ERR, EOD or EOF
620 bdat_getc(unsigned lim)
622 uschar * user_msg = NULL;
631 if (chunking_data_left > 0)
632 return lwr_receive_getc(chunking_data_left--);
634 bdat_pop_receive_functions();
636 dkim_save = dkim_collect_input;
637 dkim_collect_input = 0;
640 /* Unless PIPELINING was offered, there should be no next command
641 until after we ack that chunk */
643 if (!f.smtp_in_pipelining_advertised && !check_sync())
645 unsigned n = smtp_inend - smtp_inptr;
648 incomplete_transaction_log(US"sync failure");
649 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP protocol synchronization error "
650 "(next input sent too soon: pipelining was not advertised): "
651 "rejected \"%s\" %s next input=\"%s\"%s",
652 smtp_cmd_buffer, host_and_ident(TRUE),
653 string_printing(string_copyn(smtp_inptr, n)),
654 smtp_inend - smtp_inptr > n ? "..." : "");
655 (void) synprot_error(L_smtp_protocol_error, 554, NULL,
656 US"SMTP synchronization error");
657 goto repeat_until_rset;
660 /* If not the last, ack the received chunk. The last response is delayed
661 until after the data ACL decides on it */
663 if (chunking_state == CHUNKING_LAST)
666 dkim_collect_input = dkim_save;
667 dkim_exim_verify_feed(NULL, 0); /* notify EOD */
668 dkim_collect_input = 0;
673 smtp_printf("250 %u byte chunk received\r\n", FALSE, chunking_datasize);
674 chunking_state = CHUNKING_OFFERED;
675 DEBUG(D_receive) debug_printf("chunking state %d\n", (int)chunking_state);
677 /* Expect another BDAT cmd from input. RFC 3030 says nothing about
678 QUIT, RSET or NOOP but handling them seems obvious */
681 switch(smtp_read_command(TRUE, 1))
684 (void) synprot_error(L_smtp_protocol_error, 503, NULL,
685 US"only BDAT permissible after non-LAST BDAT");
688 switch(smtp_read_command(TRUE, 1))
690 case QUIT_CMD: smtp_quit_handler(&user_msg, &log_msg); /*FALLTHROUGH */
691 case EOF_CMD: return EOF;
692 case RSET_CMD: smtp_rset_handler(); return ERR;
693 default: if (synprot_error(L_smtp_protocol_error, 503, NULL,
694 US"only RSET accepted now") > 0)
696 goto repeat_until_rset;
700 smtp_quit_handler(&user_msg, &log_msg);
711 smtp_printf("250 OK\r\n", FALSE);
718 if (sscanf(CS smtp_cmd_data, "%u %n", &chunking_datasize, &n) < 1)
720 (void) synprot_error(L_smtp_protocol_error, 501, NULL,
721 US"missing size for BDAT command");
724 chunking_state = strcmpic(smtp_cmd_data+n, US"LAST") == 0
725 ? CHUNKING_LAST : CHUNKING_ACTIVE;
726 chunking_data_left = chunking_datasize;
727 DEBUG(D_receive) debug_printf("chunking state %d, %d bytes\n",
728 (int)chunking_state, chunking_data_left);
730 if (chunking_datasize == 0)
731 if (chunking_state == CHUNKING_LAST)
735 (void) synprot_error(L_smtp_protocol_error, 504, NULL,
736 US"zero size for BDAT command");
737 goto repeat_until_rset;
740 bdat_push_receive_functions();
742 dkim_collect_input = dkim_save;
744 break; /* to top of main loop */
753 if (chunking_data_left > 0)
754 return lwr_receive_hasc();
759 bdat_getbuf(unsigned * len)
763 if (chunking_data_left <= 0)
764 { *len = 0; return NULL; }
766 if (*len > chunking_data_left) *len = chunking_data_left;
767 buf = lwr_receive_getbuf(len); /* Either smtp_getbuf or tls_getbuf */
768 chunking_data_left -= *len;
773 bdat_flush_data(void)
775 while (chunking_data_left)
777 unsigned n = chunking_data_left;
778 if (!bdat_getbuf(&n)) break;
781 bdat_pop_receive_functions();
783 if (chunking_state != CHUNKING_LAST)
785 chunking_state = CHUNKING_OFFERED;
786 DEBUG(D_receive) debug_printf("chunking state %d\n", (int)chunking_state);
792 bdat_push_receive_functions(void)
794 /* push the current receive_* function on the "stack", and
795 replace them by bdat_getc(), which in turn will use the lwr_receive_*
796 functions to do the dirty work. */
797 if (!lwr_receive_getc)
799 lwr_receive_getc = receive_getc;
800 lwr_receive_getbuf = receive_getbuf;
801 lwr_receive_hasc = receive_hasc;
802 lwr_receive_ungetc = receive_ungetc;
806 DEBUG(D_receive) debug_printf("chunking double-push receive functions\n");
809 receive_getc = bdat_getc;
810 receive_getbuf = bdat_getbuf;
811 receive_hasc = bdat_hasc;
812 receive_ungetc = bdat_ungetc;
816 bdat_pop_receive_functions(void)
818 if (!lwr_receive_getc)
820 DEBUG(D_receive) debug_printf("chunking double-pop receive functions\n");
823 receive_getc = lwr_receive_getc;
824 receive_getbuf = lwr_receive_getbuf;
825 receive_hasc = lwr_receive_hasc;
826 receive_ungetc = lwr_receive_ungetc;
828 lwr_receive_getc = NULL;
829 lwr_receive_getbuf = NULL;
830 lwr_receive_hasc = NULL;
831 lwr_receive_ungetc = NULL;
834 /*************************************************
835 * SMTP version of ungetc() *
836 *************************************************/
838 /* Puts a character back in the input buffer. Only ever
844 Returns: the character
850 if (smtp_inptr <= smtp_inbuffer)
851 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "buffer underflow in smtp_ungetc");
861 chunking_data_left++;
862 bdat_push_receive_functions(); /* we're not done yet, calling push is safe, because it checks the state before pushing anything */
863 return lwr_receive_ungetc(ch);
868 /*************************************************
869 * SMTP version of feof() *
870 *************************************************/
872 /* Tests for a previous EOF
875 Returns: non-zero if the eof flag is set
887 /*************************************************
888 * SMTP version of ferror() *
889 *************************************************/
891 /* Tests for a previous read error, and returns with errno
892 restored to what it was when the error was detected.
895 Returns: non-zero if the error flag is set
901 errno = smtp_had_error;
902 return smtp_had_error;
907 /*************************************************
908 * Test for characters in the SMTP buffer *
909 *************************************************/
911 /* Used at the end of a message
920 return smtp_inptr < smtp_inend;
925 /*************************************************
926 * Write formatted string to SMTP channel *
927 *************************************************/
929 /* This is a separate function so that we don't have to repeat everything for
930 TLS support or debugging. It is global so that the daemon and the
931 authentication functions can use it. It does not return any error indication,
932 because major problems such as dropped connections won't show up till an output
933 flush for non-TLS connections. The smtp_fflush() function is available for
934 checking that: for convenience, TLS output errors are remembered here so that
935 they are also picked up later by smtp_fflush().
937 This function is exposed to the local_scan API; do not change the signature.
941 more further data expected
942 ... optional arguments
948 smtp_printf(const char *format, BOOL more, ...)
953 smtp_vprintf(format, more, ap);
957 /* This is split off so that verify.c:respond_printf() can, in effect, call
958 smtp_printf(), bearing in mind that in C a vararg function can't directly
959 call another vararg function, only a function which accepts a va_list.
961 This function is exposed to the local_scan API; do not change the signature.
963 /*XXX consider passing caller-info in, for string_vformat-onward */
966 smtp_vprintf(const char *format, BOOL more, va_list ap)
968 gstring gs = { .size = big_buffer_size, .ptr = 0, .s = big_buffer };
971 /* Use taint-unchecked routines for writing into big_buffer, trusting
972 that we'll never expand it. */
974 yield = !! string_vformat(&gs, SVFMT_TAINT_NOCHK, format, ap);
975 string_from_gstring(&gs);
979 uschar *msg_copy, *cr, *end;
980 msg_copy = string_copy(gs.s);
981 end = msg_copy + gs.ptr;
982 while ((cr = Ustrchr(msg_copy, '\r')) != NULL) /* lose CRs */
983 memmove(cr, cr + 1, (end--) - cr);
984 debug_printf("SMTP>> %s", msg_copy);
989 log_write(0, LOG_MAIN|LOG_PANIC, "string too large in smtp_printf()");
990 smtp_closedown(US"Unexpected error");
991 exim_exit(EXIT_FAILURE);
994 /* If this is the first output for a (non-batch) RCPT command, see if all RCPTs
995 have had the same. Note: this code is also present in smtp_respond(). It would
996 be tidier to have it only in one place, but when it was added, it was easier to
997 do it that way, so as not to have to mess with the code for the RCPT command,
998 which sometimes uses smtp_printf() and sometimes smtp_respond(). */
1000 if (fl.rcpt_in_progress)
1002 if (rcpt_smtp_response == NULL)
1003 rcpt_smtp_response = string_copy(big_buffer);
1004 else if (fl.rcpt_smtp_response_same &&
1005 Ustrcmp(rcpt_smtp_response, big_buffer) != 0)
1006 fl.rcpt_smtp_response_same = FALSE;
1007 fl.rcpt_in_progress = FALSE;
1010 /* Now write the string */
1014 tls_in.active.sock >= 0 ? (tls_write(NULL, gs.s, gs.ptr, more) < 0) :
1016 (fwrite(gs.s, gs.ptr, 1, smtp_out) == 0)
1018 smtp_write_error = -1;
1023 /*************************************************
1024 * Flush SMTP out and check for error *
1025 *************************************************/
1027 /* This function isn't currently used within Exim (it detects errors when it
1028 tries to read the next SMTP input), but is available for use in local_scan().
1029 It flushes the output and checks for errors.
1032 Returns: 0 for no error; -1 after an error
1038 if (tls_in.active.sock < 0 && fflush(smtp_out) != 0) smtp_write_error = -1;
1042 tls_in.active.sock >= 0 ? (tls_write(NULL, NULL, 0, FALSE) < 0) :
1044 (fflush(smtp_out) != 0)
1046 smtp_write_error = -1;
1048 return smtp_write_error;
1053 /*************************************************
1054 * SMTP command read timeout *
1055 *************************************************/
1057 /* Signal handler for timing out incoming SMTP commands. This attempts to
1060 Argument: signal number (SIGALRM)
1065 command_timeout_handler(int sig)
1067 had_command_timeout = sig;
1072 /*************************************************
1073 * SIGTERM received *
1074 *************************************************/
1076 /* Signal handler for handling SIGTERM. Again, try to finish tidily.
1078 Argument: signal number (SIGTERM)
1083 command_sigterm_handler(int sig)
1085 had_command_sigterm = sig;
1091 #ifdef SUPPORT_PROXY
1092 /*************************************************
1093 * Check if host is required proxy host *
1094 *************************************************/
1095 /* The function determines if inbound host will be a regular smtp host
1096 or if it is configured that it must use Proxy Protocol. A local
1104 check_proxy_protocol_host()
1108 if ( sender_host_address
1109 && (rc = verify_check_this_host(CUSS &hosts_proxy, NULL, NULL,
1110 sender_host_address, NULL)) == OK)
1113 debug_printf("Detected proxy protocol configured host\n");
1114 proxy_session = TRUE;
1116 return proxy_session;
1120 /*************************************************
1121 * Read data until newline or end of buffer *
1122 *************************************************/
1123 /* While SMTP is server-speaks-first, TLS is client-speaks-first, so we can't
1124 read an entire buffer and assume there will be nothing past a proxy protocol
1125 header. Our approach normally is to use stdio, but again that relies upon
1126 "STARTTLS\r\n" and a server response before the client starts TLS handshake, or
1127 reading _nothing_ before client TLS handshake. So we don't want to use the
1128 usual buffering reads which may read enough to block TLS starting.
1130 So unfortunately we're down to "read one byte at a time, with a syscall each,
1131 and expect a little overhead", for all proxy-opened connections which are v1,
1132 just to handle the TLS-on-connect case. Since SSL functions wrap the
1133 underlying fd, we can't assume that we can feed them any already-read content.
1135 We need to know where to read to, the max capacity, and we'll read until we
1136 get a CR and one more character. Let the caller scream if it's CR+!LF.
1138 Return the amount read.
1142 swallow_until_crlf(int fd, uschar *base, int already, int capacity)
1144 uschar *to = base + already;
1150 /* For "PROXY UNKNOWN\r\n" we, at time of writing, expect to have read
1151 up through the \r; for the _normal_ case, we haven't yet seen the \r. */
1153 cr = memchr(base, '\r', already);
1156 if ((cr - base) < already - 1)
1158 /* \r and presumed \n already within what we have; probably not
1159 actually proxy protocol, but abort cleanly. */
1162 /* \r is last character read, just need one more. */
1166 while (capacity > 0)
1168 do { ret = read(fd, to, 1); } while (ret == -1 && errno == EINTR && !had_command_timeout);
1180 /* reached end without having room for a final newline, abort */
1185 /*************************************************
1186 * Setup host for proxy protocol *
1187 *************************************************/
1188 /* The function configures the connection based on a header from the
1189 inbound host to use Proxy Protocol. The specification is very exact
1190 so exit with an error if do not find the exact required pieces. This
1191 includes an incorrect number of spaces separating args.
1194 Returns: Boolean success
1198 setup_proxy_protocol_host()
1210 struct { /* TCP/UDP over IPv4, len = 12 */
1216 struct { /* TCP/UDP over IPv6, len = 36 */
1217 uint8_t src_addr[16];
1218 uint8_t dst_addr[16];
1222 struct { /* AF_UNIX sockets, len = 216 */
1223 uschar src_addr[108];
1224 uschar dst_addr[108];
1230 /* Temp variables used in PPv2 address:port parsing */
1232 char tmpip[INET_ADDRSTRLEN];
1233 struct sockaddr_in tmpaddr;
1234 char tmpip6[INET6_ADDRSTRLEN];
1235 struct sockaddr_in6 tmpaddr6;
1237 /* We can't read "all data until end" because while SMTP is
1238 server-speaks-first, the TLS handshake is client-speaks-first, so for
1239 TLS-on-connect ports the proxy protocol header will usually be immediately
1240 followed by a TLS handshake, and with N TLS libraries, we can't reliably
1241 reinject data for reading by those. So instead we first read "enough to be
1242 safely read within the header, and figure out how much more to read".
1243 For v1 we will later read to the end-of-line, for v2 we will read based upon
1246 The v2 sig is 12 octets, and another 4 gets us the length, so we know how much
1247 data is needed total. For v1, where the line looks like:
1248 PROXY TCPn L3src L3dest SrcPort DestPort \r\n
1250 However, for v1 there's also `PROXY UNKNOWN\r\n` which is only 15 octets.
1251 We seem to support that. So, if we read 14 octets then we can tell if we're
1252 v2 or v1. If we're v1, we can continue reading as normal.
1254 If we're v2, we can't slurp up the entire header. We need the length in the
1255 15th & 16th octets, then to read everything after that.
1257 So to safely handle v1 and v2, with client-sent-first supported correctly,
1258 we have to do a minimum of 3 read calls, not 1. Eww.
1261 #define PROXY_INITIAL_READ 14
1262 #define PROXY_V2_HEADER_SIZE 16
1263 #if PROXY_INITIAL_READ > PROXY_V2_HEADER_SIZE
1264 # error Code bug in sizes of data to read for proxy usage
1269 int fd = fileno(smtp_in);
1270 const char v2sig[12] = "\x0D\x0A\x0D\x0A\x00\x0D\x0A\x51\x55\x49\x54\x0A";
1271 uschar * iptype; /* To display debug info */
1272 socklen_t vslen = sizeof(struct timeval);
1275 os_non_restarting_signal(SIGALRM, command_timeout_handler);
1276 ALARM(proxy_protocol_timeout);
1280 /* The inbound host was declared to be a Proxy Protocol host, so
1281 don't do a PEEK into the data, actually slurp up enough to be
1282 "safe". Can't take it all because TLS-on-connect clients follow
1283 immediately with TLS handshake. */
1284 ret = read(fd, &hdr, PROXY_INITIAL_READ);
1286 while (ret == -1 && errno == EINTR && !had_command_timeout);
1291 /* For v2, handle reading the length, and then the rest. */
1292 if ((ret == PROXY_INITIAL_READ) && (memcmp(&hdr.v2, v2sig, sizeof(v2sig)) == 0))
1297 /* First get the length fields. */
1300 retmore = read(fd, (uschar*)&hdr + ret, PROXY_V2_HEADER_SIZE - PROXY_INITIAL_READ);
1301 } while (retmore == -1 && errno == EINTR && !had_command_timeout);
1306 ver = (hdr.v2.ver_cmd & 0xf0) >> 4;
1308 /* May 2014: haproxy combined the version and command into one byte to
1309 allow two full bytes for the length field in order to proxy SSL
1310 connections. SSL Proxy is not supported in this version of Exim, but
1311 must still separate values here. */
1315 DEBUG(D_receive) debug_printf("Invalid Proxy Protocol version: %d\n", ver);
1319 /* The v2 header will always be 16 bytes per the spec. */
1320 size = 16 + ntohs(hdr.v2.len);
1321 DEBUG(D_receive) debug_printf("Detected PROXYv2 header, size %d (limit %d)\n",
1322 size, (int)sizeof(hdr));
1324 /* We should now have 16 octets (PROXY_V2_HEADER_SIZE), and we know the total
1325 amount that we need. Double-check that the size is not unreasonable, then
1327 if (size > sizeof(hdr))
1329 DEBUG(D_receive) debug_printf("PROXYv2 header size unreasonably large; security attack?\n");
1337 retmore = read(fd, (uschar*)&hdr + ret, size-ret);
1338 } while (retmore == -1 && errno == EINTR && !had_command_timeout);
1342 DEBUG(D_receive) debug_printf("PROXYv2: have %d/%d required octets\n", ret, size);
1343 } while (ret < size);
1345 } /* end scope for getting rest of data for v2 */
1347 /* At this point: if PROXYv2, we've read the exact size required for all data;
1348 if PROXYv1 then we've read "less than required for any valid line" and should
1351 if (ret >= 16 && memcmp(&hdr.v2, v2sig, 12) == 0)
1353 uint8_t cmd = (hdr.v2.ver_cmd & 0x0f);
1357 case 0x01: /* PROXY command */
1360 case 0x11: /* TCPv4 address type */
1362 tmpaddr.sin_addr.s_addr = hdr.v2.addr.ip4.src_addr;
1363 inet_ntop(AF_INET, &tmpaddr.sin_addr, CS &tmpip, sizeof(tmpip));
1364 if (!string_is_ip_address(US tmpip, NULL))
1366 DEBUG(D_receive) debug_printf("Invalid %s source IP\n", iptype);
1369 proxy_local_address = sender_host_address;
1370 sender_host_address = string_copy(US tmpip);
1371 tmpport = ntohs(hdr.v2.addr.ip4.src_port);
1372 proxy_local_port = sender_host_port;
1373 sender_host_port = tmpport;
1374 /* Save dest ip/port */
1375 tmpaddr.sin_addr.s_addr = hdr.v2.addr.ip4.dst_addr;
1376 inet_ntop(AF_INET, &tmpaddr.sin_addr, CS &tmpip, sizeof(tmpip));
1377 if (!string_is_ip_address(US tmpip, NULL))
1379 DEBUG(D_receive) debug_printf("Invalid %s dest port\n", iptype);
1382 proxy_external_address = string_copy(US tmpip);
1383 tmpport = ntohs(hdr.v2.addr.ip4.dst_port);
1384 proxy_external_port = tmpport;
1386 case 0x21: /* TCPv6 address type */
1388 memmove(tmpaddr6.sin6_addr.s6_addr, hdr.v2.addr.ip6.src_addr, 16);
1389 inet_ntop(AF_INET6, &tmpaddr6.sin6_addr, CS &tmpip6, sizeof(tmpip6));
1390 if (!string_is_ip_address(US tmpip6, NULL))
1392 DEBUG(D_receive) debug_printf("Invalid %s source IP\n", iptype);
1395 proxy_local_address = sender_host_address;
1396 sender_host_address = string_copy(US tmpip6);
1397 tmpport = ntohs(hdr.v2.addr.ip6.src_port);
1398 proxy_local_port = sender_host_port;
1399 sender_host_port = tmpport;
1400 /* Save dest ip/port */
1401 memmove(tmpaddr6.sin6_addr.s6_addr, hdr.v2.addr.ip6.dst_addr, 16);
1402 inet_ntop(AF_INET6, &tmpaddr6.sin6_addr, CS &tmpip6, sizeof(tmpip6));
1403 if (!string_is_ip_address(US tmpip6, NULL))
1405 DEBUG(D_receive) debug_printf("Invalid %s dest port\n", iptype);
1408 proxy_external_address = string_copy(US tmpip6);
1409 tmpport = ntohs(hdr.v2.addr.ip6.dst_port);
1410 proxy_external_port = tmpport;
1414 debug_printf("Unsupported PROXYv2 connection type: 0x%02x\n",
1418 /* Unsupported protocol, keep local connection address */
1420 case 0x00: /* LOCAL command */
1421 /* Keep local connection address for LOCAL */
1426 debug_printf("Unsupported PROXYv2 command: 0x%x\n", cmd);
1430 else if (ret >= 8 && memcmp(hdr.v1.line, "PROXY", 5) == 0)
1434 uschar *sp; /* Utility variables follow */
1439 /* get the rest of the line */
1440 r2 = swallow_until_crlf(fd, (uschar*)&hdr, ret, sizeof(hdr)-ret);
1445 p = string_copy(hdr.v1.line);
1446 end = memchr(p, '\r', ret - 1);
1448 if (!end || (end == (uschar*)&hdr + ret) || end[1] != '\n')
1450 DEBUG(D_receive) debug_printf("Partial or invalid PROXY header\n");
1453 *end = '\0'; /* Terminate the string */
1454 size = end + 2 - p; /* Skip header + CRLF */
1455 DEBUG(D_receive) debug_printf("Detected PROXYv1 header\n");
1456 DEBUG(D_receive) debug_printf("Bytes read not within PROXY header: %d\n", ret - size);
1457 /* Step through the string looking for the required fields. Ensure
1458 strict adherence to required formatting, exit for any error. */
1460 if (!isspace(*(p++)))
1462 DEBUG(D_receive) debug_printf("Missing space after PROXY command\n");
1465 if (!Ustrncmp(p, CCS"TCP4", 4))
1467 else if (!Ustrncmp(p,CCS"TCP6", 4))
1469 else if (!Ustrncmp(p,CCS"UNKNOWN", 7))
1471 iptype = US"Unknown";
1476 DEBUG(D_receive) debug_printf("Invalid TCP type\n");
1480 p += Ustrlen(iptype);
1481 if (!isspace(*(p++)))
1483 DEBUG(D_receive) debug_printf("Missing space after TCP4/6 command\n");
1486 /* Find the end of the arg */
1487 if ((sp = Ustrchr(p, ' ')) == NULL)
1490 debug_printf("Did not find proxied src %s\n", iptype);
1494 if(!string_is_ip_address(p, NULL))
1497 debug_printf("Proxied src arg is not an %s address\n", iptype);
1500 proxy_local_address = sender_host_address;
1501 sender_host_address = p;
1503 if ((sp = Ustrchr(p, ' ')) == NULL)
1506 debug_printf("Did not find proxy dest %s\n", iptype);
1510 if(!string_is_ip_address(p, NULL))
1513 debug_printf("Proxy dest arg is not an %s address\n", iptype);
1516 proxy_external_address = p;
1518 if ((sp = Ustrchr(p, ' ')) == NULL)
1520 DEBUG(D_receive) debug_printf("Did not find proxied src port\n");
1524 tmp_port = strtol(CCS p, &endc, 10);
1525 if (*endc || tmp_port == 0)
1528 debug_printf("Proxied src port '%s' not an integer\n", p);
1531 proxy_local_port = sender_host_port;
1532 sender_host_port = tmp_port;
1534 if ((sp = Ustrchr(p, '\0')) == NULL)
1536 DEBUG(D_receive) debug_printf("Did not find proxy dest port\n");
1539 tmp_port = strtol(CCS p, &endc, 10);
1540 if (*endc || tmp_port == 0)
1543 debug_printf("Proxy dest port '%s' not an integer\n", p);
1546 proxy_external_port = tmp_port;
1547 /* Already checked for /r /n above. Good V1 header received. */
1551 /* Wrong protocol */
1552 DEBUG(D_receive) debug_printf("Invalid proxy protocol version negotiation\n");
1553 (void) swallow_until_crlf(fd, (uschar*)&hdr, ret, sizeof(hdr)-ret);
1559 debug_printf("Valid %s sender from Proxy Protocol header\n", iptype);
1560 yield = proxy_session;
1562 /* Don't flush any potential buffer contents. Any input on proxyfail
1563 should cause a synchronization failure */
1566 DEBUG(D_receive) if (had_command_timeout)
1567 debug_printf("Timeout while reading proxy header\n");
1572 sender_host_name = NULL;
1573 (void) host_name_lookup();
1574 host_build_sender_fullhost();
1578 f.proxy_session_failed = TRUE;
1580 debug_printf("Failure to extract proxied host, only QUIT allowed\n");
1588 /*************************************************
1589 * Read one command line *
1590 *************************************************/
1592 /* Strictly, SMTP commands coming over the net are supposed to end with CRLF.
1593 There are sites that don't do this, and in any case internal SMTP probably
1594 should check only for LF. Consequently, we check here for LF only. The line
1595 ends up with [CR]LF removed from its end. If we get an overlong line, treat as
1596 an unknown command. The command is read into the global smtp_cmd_buffer so that
1597 it is available via $smtp_command.
1599 The character reading routine sets up a timeout for each block actually read
1600 from the input (which may contain more than one command). We set up a special
1601 signal handler that closes down the session on a timeout. Control does not
1602 return when it runs.
1605 check_sync if TRUE, check synchronization rules if global option is TRUE
1606 buffer_lim maximum to buffer in lower layer
1608 Returns: a code identifying the command (enumerated above)
1612 smtp_read_command(BOOL check_sync, unsigned buffer_lim)
1616 BOOL hadnull = FALSE;
1618 had_command_timeout = 0;
1619 os_non_restarting_signal(SIGALRM, command_timeout_handler);
1621 while ((c = (receive_getc)(buffer_lim)) != '\n' && c != EOF)
1623 if (ptr >= SMTP_CMD_BUFFER_SIZE)
1625 os_non_restarting_signal(SIGALRM, sigalrm_handler);
1633 smtp_cmd_buffer[ptr++] = c;
1636 receive_linecount++; /* For BSMTP errors */
1637 os_non_restarting_signal(SIGALRM, sigalrm_handler);
1639 /* If hit end of file, return pseudo EOF command. Whether we have a
1640 part-line already read doesn't matter, since this is an error state. */
1642 if (c == EOF) return EOF_CMD;
1644 /* Remove any CR and white space at the end of the line, and terminate the
1647 while (ptr > 0 && isspace(smtp_cmd_buffer[ptr-1])) ptr--;
1648 smtp_cmd_buffer[ptr] = 0;
1650 DEBUG(D_receive) debug_printf("SMTP<< %s\n", smtp_cmd_buffer);
1652 /* NULLs are not allowed in SMTP commands */
1654 if (hadnull) return BADCHAR_CMD;
1656 /* Scan command list and return identity, having set the data pointer
1657 to the start of the actual data characters. Check for SMTP synchronization
1660 for (smtp_cmd_list * p = cmd_list; p < cmd_list_end; p++)
1662 #ifdef SUPPORT_PROXY
1663 /* Only allow QUIT command if Proxy Protocol parsing failed */
1664 if (proxy_session && f.proxy_session_failed && p->cmd != QUIT_CMD)
1668 && strncmpic(smtp_cmd_buffer, US p->name, p->len) == 0
1669 && ( smtp_cmd_buffer[p->len-1] == ':' /* "mail from:" or "rcpt to:" */
1670 || smtp_cmd_buffer[p->len] == 0
1671 || smtp_cmd_buffer[p->len] == ' '
1674 if (smtp_inptr < smtp_inend && /* Outstanding input */
1675 p->cmd < sync_cmd_limit && /* Command should sync */
1676 check_sync && /* Local flag set */
1677 smtp_enforce_sync && /* Global flag set */
1678 sender_host_address != NULL && /* Not local input */
1679 !f.sender_host_notsocket) /* Really is a socket */
1682 /* The variables $smtp_command and $smtp_command_argument point into the
1683 unmodified input buffer. A copy of the latter is taken for actual
1684 processing, so that it can be chopped up into separate parts if necessary,
1685 for example, when processing a MAIL command options such as SIZE that can
1686 follow the sender address. */
1688 smtp_cmd_argument = smtp_cmd_buffer + p->len;
1689 while (isspace(*smtp_cmd_argument)) smtp_cmd_argument++;
1690 Ustrcpy(smtp_data_buffer, smtp_cmd_argument);
1691 smtp_cmd_data = smtp_data_buffer;
1693 /* Count non-mail commands from those hosts that are controlled in this
1694 way. The default is all hosts. We don't waste effort checking the list
1695 until we get a non-mail command, but then cache the result to save checking
1696 again. If there's a DEFER while checking the host, assume it's in the list.
1698 Note that one instance of RSET, EHLO/HELO, and STARTTLS is allowed at the
1699 start of each incoming message by fiddling with the value in the table. */
1701 if (!p->is_mail_cmd)
1703 if (count_nonmail == TRUE_UNSET) count_nonmail =
1704 verify_check_host(&smtp_accept_max_nonmail_hosts) != FAIL;
1705 if (count_nonmail && ++nonmail_command_count > smtp_accept_max_nonmail)
1706 return TOO_MANY_NONMAIL_CMD;
1709 /* If there is data for a command that does not expect it, generate the
1712 return (p->has_arg || *smtp_cmd_data == 0)? p->cmd : BADARG_CMD;
1716 #ifdef SUPPORT_PROXY
1717 /* Only allow QUIT command if Proxy Protocol parsing failed */
1718 if (proxy_session && f.proxy_session_failed)
1719 return PROXY_FAIL_IGNORE_CMD;
1722 /* Enforce synchronization for unknown commands */
1724 if ( smtp_inptr < smtp_inend /* Outstanding input */
1725 && check_sync /* Local flag set */
1726 && smtp_enforce_sync /* Global flag set */
1727 && sender_host_address /* Not local input */
1728 && !f.sender_host_notsocket) /* Really is a socket */
1736 /*************************************************
1737 * Forced closedown of call *
1738 *************************************************/
1740 /* This function is called from log.c when Exim is dying because of a serious
1741 disaster, and also from some other places. If an incoming non-batched SMTP
1742 channel is open, it swallows the rest of the incoming message if in the DATA
1743 phase, sends the reply string, and gives an error to all subsequent commands
1744 except QUIT. The existence of an SMTP call is detected by the non-NULLness of
1748 message SMTP reply string to send, excluding the code
1754 smtp_closedown(uschar *message)
1756 if (!smtp_in || smtp_batched_input) return;
1757 receive_swallow_smtp();
1758 smtp_printf("421 %s\r\n", FALSE, message);
1760 for (;;) switch(smtp_read_command(FALSE, GETC_BUFFER_UNLIMITED))
1766 f.smtp_in_quit = TRUE;
1767 smtp_printf("221 %s closing connection\r\n", FALSE, smtp_active_hostname);
1772 smtp_printf("250 Reset OK\r\n", FALSE);
1776 smtp_printf("421 %s\r\n", FALSE, message);
1784 /*************************************************
1785 * Set up connection info for logging *
1786 *************************************************/
1788 /* This function is called when logging information about an SMTP connection.
1789 It sets up appropriate source information, depending on the type of connection.
1790 If sender_fullhost is NULL, we are at a very early stage of the connection;
1791 just use the IP address.
1794 Returns: a string describing the connection
1798 smtp_get_connection_info(void)
1800 const uschar * hostname = sender_fullhost
1801 ? sender_fullhost : sender_host_address;
1804 return string_sprintf("SMTP connection from %s", hostname);
1806 if (f.sender_host_unknown || f.sender_host_notsocket)
1807 return string_sprintf("SMTP connection from %s", sender_ident);
1810 return string_sprintf("SMTP connection from %s (via inetd)", hostname);
1812 if (LOGGING(incoming_interface) && interface_address)
1813 return string_sprintf("SMTP connection from %s I=[%s]:%d", hostname,
1814 interface_address, interface_port);
1816 return string_sprintf("SMTP connection from %s", hostname);
1822 /* Append TLS-related information to a log line
1825 g String under construction: allocated string to extend, or NULL
1827 Returns: Allocated string or NULL
1830 s_tlslog(gstring * g)
1832 if (LOGGING(tls_cipher) && tls_in.cipher)
1834 g = string_append(g, 2, US" X=", tls_in.cipher);
1835 #ifndef DISABLE_TLS_RESUME
1836 if (LOGGING(tls_resumption) && tls_in.resumption & RESUME_USED)
1837 g = string_catn(g, US"*", 1);
1840 if (LOGGING(tls_certificate_verified) && tls_in.cipher)
1841 g = string_append(g, 2, US" CV=", tls_in.certificate_verified? "yes":"no");
1842 if (LOGGING(tls_peerdn) && tls_in.peerdn)
1843 g = string_append(g, 3, US" DN=\"", string_printing(tls_in.peerdn), US"\"");
1844 if (LOGGING(tls_sni) && tls_in.sni)
1845 g = string_append(g, 2, US" SNI=", string_printing2(tls_in.sni, SP_TAB|SP_SPACE));
1853 s_connhad_log(gstring * g)
1855 const uschar * sep = smtp_connection_had[SMTP_HBUFF_SIZE-1] != SCH_NONE
1856 ? US" C=..." : US" C=";
1858 for (int i = smtp_ch_index; i < SMTP_HBUFF_SIZE; i++)
1859 if (smtp_connection_had[i] != SCH_NONE)
1861 g = string_append(g, 2, sep, smtp_names[smtp_connection_had[i]]);
1864 for (int i = 0; i < smtp_ch_index; i++, sep = US",")
1865 g = string_append(g, 2, sep, smtp_names[smtp_connection_had[i]]);
1870 /*************************************************
1871 * Log lack of MAIL if so configured *
1872 *************************************************/
1874 /* This function is called when an SMTP session ends. If the log selector
1875 smtp_no_mail is set, write a log line giving some details of what has happened
1876 in the SMTP session.
1883 smtp_log_no_mail(void)
1888 if (smtp_mailcmd_count > 0 || !LOGGING(smtp_no_mail))
1891 if (sender_host_authenticated)
1893 g = string_append(g, 2, US" A=", sender_host_authenticated);
1894 if (authenticated_id) g = string_append(g, 2, US":", authenticated_id);
1901 g = s_connhad_log(g);
1903 if (!(s = string_from_gstring(g))) s = US"";
1905 log_write(0, LOG_MAIN, "no MAIL in %sSMTP connection from %s D=%s%s",
1906 f.tcp_in_fastopen ? f.tcp_in_fastopen_data ? US"TFO* " : US"TFO " : US"",
1907 host_and_ident(FALSE), string_timesince(&smtp_connection_start), s);
1911 /* Return list of recent smtp commands */
1916 gstring * list = NULL;
1919 for (int i = smtp_ch_index; i < SMTP_HBUFF_SIZE; i++)
1920 if (smtp_connection_had[i] != SCH_NONE)
1921 list = string_append_listele(list, ',', smtp_names[smtp_connection_had[i]]);
1923 for (int i = 0; i < smtp_ch_index; i++)
1924 list = string_append_listele(list, ',', smtp_names[smtp_connection_had[i]]);
1926 s = string_from_gstring(list);
1927 return s ? s : US"";
1933 /*************************************************
1934 * Check HELO line and set sender_helo_name *
1935 *************************************************/
1937 /* Check the format of a HELO line. The data for HELO/EHLO is supposed to be
1938 the domain name of the sending host, or an ip literal in square brackets. The
1939 argument is placed in sender_helo_name, which is in malloc store, because it
1940 must persist over multiple incoming messages. If helo_accept_junk is set, this
1941 host is permitted to send any old junk (needed for some broken hosts).
1942 Otherwise, helo_allow_chars can be used for rogue characters in general
1943 (typically people want to let in underscores).
1946 s the data portion of the line (already past any white space)
1948 Returns: TRUE or FALSE
1952 check_helo(uschar *s)
1955 uschar *end = s + Ustrlen(s);
1956 BOOL yield = fl.helo_accept_junk;
1958 /* Discard any previous helo name */
1960 sender_helo_name = NULL;
1962 /* Skip tests if junk is permitted. */
1966 /* Allow the new standard form for IPv6 address literals, namely,
1967 [IPv6:....], and because someone is bound to use it, allow an equivalent
1968 IPv4 form. Allow plain addresses as well. */
1975 if (strncmpic(s, US"[IPv6:", 6) == 0)
1976 yield = (string_is_ip_address(s+6, NULL) == 6);
1977 else if (strncmpic(s, US"[IPv4:", 6) == 0)
1978 yield = (string_is_ip_address(s+6, NULL) == 4);
1980 yield = (string_is_ip_address(s+1, NULL) != 0);
1985 /* Non-literals must be alpha, dot, hyphen, plus any non-valid chars
1986 that have been configured (usually underscore - sigh). */
1989 for (yield = TRUE; *s; s++)
1990 if (!isalnum(*s) && *s != '.' && *s != '-' &&
1991 Ustrchr(helo_allow_chars, *s) == NULL)
1997 /* Save argument if OK */
1999 if (yield) sender_helo_name = string_copy_perm(start, TRUE);
2007 /*************************************************
2008 * Extract SMTP command option *
2009 *************************************************/
2011 /* This function picks the next option setting off the end of smtp_cmd_data. It
2012 is called for MAIL FROM and RCPT TO commands, to pick off the optional ESMTP
2013 things that can appear there.
2016 name point this at the name
2017 value point this at the data string
2019 Returns: TRUE if found an option
2023 extract_option(uschar **name, uschar **value)
2027 if (Ustrlen(smtp_cmd_data) <= 0) return FALSE;
2028 v = smtp_cmd_data + Ustrlen(smtp_cmd_data) - 1;
2029 while (v > smtp_cmd_data && isspace(*v)) v--;
2032 while (v > smtp_cmd_data && *v != '=' && !isspace(*v))
2034 /* Take care to not stop at a space embedded in a quoted local-part */
2037 do v--; while (v > smtp_cmd_data && *v != '"');
2038 if (v <= smtp_cmd_data) return FALSE;
2042 if (v <= smtp_cmd_data) return FALSE;
2047 while (n > smtp_cmd_data && isalpha(n[-1])) n--;
2048 /* RFC says SP, but TAB seen in wild and other major MTAs accept it */
2049 if (n <= smtp_cmd_data || !isspace(n[-1])) return FALSE;
2066 /*************************************************
2067 * Reset for new message *
2068 *************************************************/
2070 /* This function is called whenever the SMTP session is reset from
2071 within either of the setup functions; also from the daemon loop.
2073 Argument: the stacking pool storage reset point
2078 smtp_reset(void *reset_point)
2080 recipients_list = NULL;
2081 rcpt_count = rcpt_defer_count = rcpt_fail_count =
2082 raw_recipients_count = recipients_count = recipients_list_max = 0;
2083 message_linecount = 0;
2085 message_body = message_body_end = NULL;
2086 acl_added_headers = NULL;
2087 acl_removed_headers = NULL;
2088 f.queue_only_policy = FALSE;
2089 rcpt_smtp_response = NULL;
2090 fl.rcpt_smtp_response_same = TRUE;
2091 fl.rcpt_in_progress = FALSE;
2092 f.deliver_freeze = FALSE; /* Can be set by ACL */
2093 freeze_tell = freeze_tell_config; /* Can be set by ACL */
2094 fake_response = OK; /* Can be set by ACL */
2095 #ifdef WITH_CONTENT_SCAN
2096 f.no_mbox_unspool = FALSE; /* Can be set by ACL */
2098 f.submission_mode = FALSE; /* Can be set by ACL */
2099 f.suppress_local_fixups = f.suppress_local_fixups_default; /* Can be set by ACL */
2100 f.active_local_from_check = local_from_check; /* Can be set by ACL */
2101 f.active_local_sender_retain = local_sender_retain; /* Can be set by ACL */
2102 sending_ip_address = NULL;
2103 return_path = sender_address = NULL;
2104 deliver_localpart_data = deliver_domain_data =
2105 recipient_data = sender_data = NULL; /* Can be set by ACL */
2106 recipient_verify_failure = NULL;
2107 deliver_localpart_parent = deliver_localpart_orig = NULL;
2108 deliver_domain_parent = deliver_domain_orig = NULL;
2109 callout_address = NULL;
2110 submission_name = NULL; /* Can be set by ACL */
2111 raw_sender = NULL; /* After SMTP rewrite, before qualifying */
2112 sender_address_unrewritten = NULL; /* Set only after verify rewrite */
2113 sender_verified_list = NULL; /* No senders verified */
2114 memset(sender_address_cache, 0, sizeof(sender_address_cache));
2115 memset(sender_domain_cache, 0, sizeof(sender_domain_cache));
2117 authenticated_sender = NULL;
2118 #ifdef EXPERIMENTAL_BRIGHTMAIL
2120 bmi_verdicts = NULL;
2122 dnslist_domain = dnslist_matched = NULL;
2124 spf_header_comment = spf_received = spf_result = spf_smtp_comment = NULL;
2125 spf_result_guessed = FALSE;
2127 #ifndef DISABLE_DKIM
2128 dkim_cur_signer = dkim_signers =
2129 dkim_signing_domain = dkim_signing_selector = dkim_signatures = NULL;
2130 dkim_cur_signer = dkim_signers = dkim_signing_domain = dkim_signing_selector = NULL;
2131 f.dkim_disable_verify = FALSE;
2132 dkim_collect_input = 0;
2133 dkim_verify_overall = dkim_verify_status = dkim_verify_reason = NULL;
2134 dkim_key_length = 0;
2136 #ifdef SUPPORT_DMARC
2137 f.dmarc_has_been_checked = f.dmarc_disable_verify = f.dmarc_enable_forensic = FALSE;
2138 dmarc_domain_policy = dmarc_status = dmarc_status_text =
2139 dmarc_used_domain = NULL;
2141 #ifdef EXPERIMENTAL_ARC
2142 arc_state = arc_state_reason = NULL;
2143 arc_received_instance = 0;
2147 deliver_host = deliver_host_address = NULL; /* Can be set by ACL */
2148 #ifndef DISABLE_PRDR
2149 prdr_requested = FALSE;
2152 message_smtputf8 = FALSE;
2154 body_linecount = body_zerocount = 0;
2156 sender_rate = sender_rate_limit = sender_rate_period = NULL;
2157 ratelimiters_mail = NULL; /* Updated by ratelimit ACL condition */
2158 /* Note that ratelimiters_conn persists across resets. */
2160 /* Reset message ACL variables */
2164 /* Warning log messages are saved in malloc store. They are saved to avoid
2165 repetition in the same message, but it seems right to repeat them for different
2168 while (acl_warn_logged)
2170 string_item *this = acl_warn_logged;
2171 acl_warn_logged = acl_warn_logged->next;
2176 store_reset(reset_point);
2179 return store_mark();
2186 /*************************************************
2187 * Initialize for incoming batched SMTP message *
2188 *************************************************/
2190 /* This function is called from smtp_setup_msg() in the case when
2191 smtp_batched_input is true. This happens when -bS is used to pass a whole batch
2192 of messages in one file with SMTP commands between them. All errors must be
2193 reported by sending a message, and only MAIL FROM, RCPT TO, and DATA are
2194 relevant. After an error on a sender, or an invalid recipient, the remainder
2195 of the message is skipped. The value of received_protocol is already set.
2198 Returns: > 0 message successfully started (reached DATA)
2199 = 0 QUIT read or end of file reached
2200 < 0 should not occur
2204 smtp_setup_batch_msg(void)
2207 rmark reset_point = store_mark();
2209 /* Save the line count at the start of each transaction - single commands
2210 like HELO and RSET count as whole transactions. */
2212 bsmtp_transaction_linecount = receive_linecount;
2214 if ((receive_feof)()) return 0; /* Treat EOF as QUIT */
2216 cancel_cutthrough_connection(TRUE, US"smtp_setup_batch_msg");
2217 reset_point = smtp_reset(reset_point); /* Reset for start of message */
2219 /* Deal with SMTP commands. This loop is exited by setting done to a POSITIVE
2220 value. The values are 2 larger than the required yield of the function. */
2225 uschar *recipient = NULL;
2226 int start, end, sender_domain, recipient_domain;
2228 switch(smtp_read_command(FALSE, GETC_BUFFER_UNLIMITED))
2230 /* The HELO/EHLO commands set sender_address_helo if they have
2231 valid data; otherwise they are ignored, except that they do
2232 a reset of the state. */
2237 check_helo(smtp_cmd_data);
2241 cancel_cutthrough_connection(TRUE, US"RSET received");
2242 reset_point = smtp_reset(reset_point);
2243 bsmtp_transaction_linecount = receive_linecount;
2247 /* The MAIL FROM command requires an address as an operand. All we
2248 do here is to parse it for syntactic correctness. The form "<>" is
2249 a special case which converts into an empty string. The start/end
2250 pointers in the original are not used further for this address, as
2251 it is the canonical extracted address which is all that is kept. */
2254 smtp_mailcmd_count++; /* Count for no-mail log */
2256 /* The function moan_smtp_batch() does not return. */
2257 moan_smtp_batch(smtp_cmd_buffer, "503 Sender already given");
2259 if (smtp_cmd_data[0] == 0)
2260 /* The function moan_smtp_batch() does not return. */
2261 moan_smtp_batch(smtp_cmd_buffer, "501 MAIL FROM must have an address operand");
2263 /* Reset to start of message */
2265 cancel_cutthrough_connection(TRUE, US"MAIL received");
2266 reset_point = smtp_reset(reset_point);
2268 /* Apply SMTP rewrite */
2270 raw_sender = rewrite_existflags & rewrite_smtp
2271 /* deconst ok as smtp_cmd_data was not const */
2272 ? US rewrite_one(smtp_cmd_data, rewrite_smtp|rewrite_smtp_sender, NULL,
2273 FALSE, US"", global_rewrite_rules)
2276 /* Extract the address; the TRUE flag allows <> as valid */
2279 parse_extract_address(raw_sender, &errmess, &start, &end, &sender_domain,
2283 /* The function moan_smtp_batch() does not return. */
2284 moan_smtp_batch(smtp_cmd_buffer, "501 %s", errmess);
2286 sender_address = string_copy(raw_sender);
2288 /* Qualify unqualified sender addresses if permitted to do so. */
2291 && sender_address[0] != 0 && sender_address[0] != '@')
2292 if (f.allow_unqualified_sender)
2294 /* deconst ok as sender_address was not const */
2295 sender_address = US rewrite_address_qualify(sender_address, FALSE);
2296 DEBUG(D_receive) debug_printf("unqualified address %s accepted "
2297 "and rewritten\n", raw_sender);
2299 /* The function moan_smtp_batch() does not return. */
2301 moan_smtp_batch(smtp_cmd_buffer, "501 sender address must contain "
2306 /* The RCPT TO command requires an address as an operand. All we do
2307 here is to parse it for syntactic correctness. There may be any number
2308 of RCPT TO commands, specifying multiple senders. We build them all into
2309 a data structure that is in argc/argv format. The start/end values
2310 given by parse_extract_address are not used, as we keep only the
2311 extracted address. */
2314 if (!sender_address)
2315 /* The function moan_smtp_batch() does not return. */
2316 moan_smtp_batch(smtp_cmd_buffer, "503 No sender yet given");
2318 if (smtp_cmd_data[0] == 0)
2319 /* The function moan_smtp_batch() does not return. */
2320 moan_smtp_batch(smtp_cmd_buffer,
2321 "501 RCPT TO must have an address operand");
2323 /* Check maximum number allowed */
2325 if (recipients_max > 0 && recipients_count + 1 > recipients_max)
2326 /* The function moan_smtp_batch() does not return. */
2327 moan_smtp_batch(smtp_cmd_buffer, "%s too many recipients",
2328 recipients_max_reject? "552": "452");
2330 /* Apply SMTP rewrite, then extract address. Don't allow "<>" as a
2331 recipient address */
2333 recipient = rewrite_existflags & rewrite_smtp
2334 /* deconst ok as smtp_cmd_data was not const */
2335 ? US rewrite_one(smtp_cmd_data, rewrite_smtp, NULL, FALSE, US"",
2336 global_rewrite_rules)
2339 recipient = parse_extract_address(recipient, &errmess, &start, &end,
2340 &recipient_domain, FALSE);
2343 /* The function moan_smtp_batch() does not return. */
2344 moan_smtp_batch(smtp_cmd_buffer, "501 %s", errmess);
2346 /* If the recipient address is unqualified, qualify it if permitted. Then
2347 add it to the list of recipients. */
2349 if (!recipient_domain)
2350 if (f.allow_unqualified_recipient)
2352 DEBUG(D_receive) debug_printf("unqualified address %s accepted\n",
2354 /* deconst ok as recipient was not const */
2355 recipient = US rewrite_address_qualify(recipient, TRUE);
2357 /* The function moan_smtp_batch() does not return. */
2359 moan_smtp_batch(smtp_cmd_buffer,
2360 "501 recipient address must contain a domain");
2362 receive_add_recipient(recipient, -1);
2366 /* The DATA command is legal only if it follows successful MAIL FROM
2367 and RCPT TO commands. This function is complete when a valid DATA
2368 command is encountered. */
2371 if (!sender_address || recipients_count <= 0)
2372 /* The function moan_smtp_batch() does not return. */
2373 if (!sender_address)
2374 moan_smtp_batch(smtp_cmd_buffer,
2375 "503 MAIL FROM:<sender> command must precede DATA");
2377 moan_smtp_batch(smtp_cmd_buffer,
2378 "503 RCPT TO:<recipient> must precede DATA");
2381 done = 3; /* DATA successfully achieved */
2382 message_ended = END_NOTENDED; /* Indicate in middle of message */
2387 /* The VRFY, EXPN, HELP, ETRN, and NOOP commands are ignored. */
2394 bsmtp_transaction_linecount = receive_linecount;
2399 f.smtp_in_quit = TRUE;
2406 /* The function moan_smtp_batch() does not return. */
2407 moan_smtp_batch(smtp_cmd_buffer, "501 Unexpected argument data");
2412 /* The function moan_smtp_batch() does not return. */
2413 moan_smtp_batch(smtp_cmd_buffer, "501 Unexpected NULL in SMTP command");
2418 /* The function moan_smtp_batch() does not return. */
2419 moan_smtp_batch(smtp_cmd_buffer, "500 Command unrecognized");
2424 return done - 2; /* Convert yield values */
2432 smtp_log_tls_fail(uschar * errstr)
2434 uschar * conn_info = smtp_get_connection_info();
2436 if (Ustrncmp(conn_info, US"SMTP ", 5) == 0) conn_info += 5;
2437 /* I'd like to get separated H= here, but too hard for now */
2439 log_write(0, LOG_MAIN, "TLS error on %s %s", conn_info, errstr);
2453 socklen_t len = sizeof(is_fastopen);
2455 /* The tinfo TCPOPT_FAST_OPEN bit seems unreliable, and we don't see state
2456 TCP_SYN_RCV (as of 12.1) so no idea about data-use. */
2458 if (getsockopt(fileno(smtp_out), IPPROTO_TCP, TCP_FASTOPEN, &is_fastopen, &len) == 0)
2463 debug_printf("TFO mode connection (TCP_FASTOPEN getsockopt)\n");
2464 f.tcp_in_fastopen = TRUE;
2467 else DEBUG(D_receive)
2468 debug_printf("TCP_INFO getsockopt: %s\n", strerror(errno));
2470 # elif defined(TCP_INFO)
2471 struct tcp_info tinfo;
2472 socklen_t len = sizeof(tinfo);
2474 if (getsockopt(fileno(smtp_out), IPPROTO_TCP, TCP_INFO, &tinfo, &len) == 0)
2475 # ifdef TCPI_OPT_SYN_DATA /* FreeBSD 11,12 do not seem to have this yet */
2476 if (tinfo.tcpi_options & TCPI_OPT_SYN_DATA)
2479 debug_printf("TFO mode connection (ACKd data-on-SYN)\n");
2480 f.tcp_in_fastopen_data = f.tcp_in_fastopen = TRUE;
2484 if (tinfo.tcpi_state == TCP_SYN_RECV) /* Not seen on FreeBSD 12.1 */
2487 debug_printf("TFO mode connection (state TCP_SYN_RECV)\n");
2488 f.tcp_in_fastopen = TRUE;
2490 else DEBUG(D_receive)
2491 debug_printf("TCP_INFO getsockopt: %s\n", strerror(errno));
2497 /*************************************************
2498 * Start an SMTP session *
2499 *************************************************/
2501 /* This function is called at the start of an SMTP session. Thereafter,
2502 smtp_setup_msg() is called to initiate each separate message. This
2503 function does host-specific testing, and outputs the banner line.
2506 Returns: FALSE if the session can not continue; something has
2507 gone wrong, or the connection to the host is blocked
2511 smtp_start_session(void)
2514 uschar *user_msg, *log_msg;
2519 gettimeofday(&smtp_connection_start, NULL);
2520 for (smtp_ch_index = 0; smtp_ch_index < SMTP_HBUFF_SIZE; smtp_ch_index++)
2521 smtp_connection_had[smtp_ch_index] = SCH_NONE;
2524 /* Default values for certain variables */
2526 fl.helo_seen = fl.esmtp = fl.helo_accept_junk = FALSE;
2527 smtp_mailcmd_count = 0;
2528 count_nonmail = TRUE_UNSET;
2529 synprot_error_count = unknown_command_count = nonmail_command_count = 0;
2530 smtp_delay_mail = smtp_rlm_base;
2531 fl.auth_advertised = FALSE;
2532 f.smtp_in_pipelining_advertised = f.smtp_in_pipelining_used = FALSE;
2533 f.pipelining_enable = TRUE;
2534 sync_cmd_limit = NON_SYNC_CMD_NON_PIPELINING;
2535 fl.smtp_exit_function_called = FALSE; /* For avoiding loop in not-quit exit */
2537 /* If receiving by -bs from a trusted user, or testing with -bh, we allow
2538 authentication settings from -oMaa to remain in force. */
2540 if (!host_checking && !f.sender_host_notsocket)
2541 sender_host_auth_pubname = sender_host_authenticated = NULL;
2542 authenticated_by = NULL;
2545 tls_in.ver = tls_in.cipher = tls_in.peerdn = NULL;
2546 tls_in.ourcert = tls_in.peercert = NULL;
2548 tls_in.ocsp = OCSP_NOT_REQ;
2549 fl.tls_advertised = FALSE;
2551 fl.dsn_advertised = FALSE;
2553 fl.smtputf8_advertised = FALSE;
2556 /* Reset ACL connection variables */
2560 /* Allow for trailing 0 in the command and data buffers. Tainted. */
2562 smtp_cmd_buffer = store_get_perm(2*SMTP_CMD_BUFFER_SIZE + 2, TRUE);
2564 smtp_cmd_buffer[0] = 0;
2565 smtp_data_buffer = smtp_cmd_buffer + SMTP_CMD_BUFFER_SIZE + 1;
2567 /* For batched input, the protocol setting can be overridden from the
2568 command line by a trusted caller. */
2570 if (smtp_batched_input)
2572 if (!received_protocol) received_protocol = US"local-bsmtp";
2575 /* For non-batched SMTP input, the protocol setting is forced here. It will be
2576 reset later if any of EHLO/AUTH/STARTTLS are received. */
2580 (sender_host_address ? protocols : protocols_local) [pnormal];
2582 /* Set up the buffer for inputting using direct read() calls, and arrange to
2583 call the local functions instead of the standard C ones. Place a NUL at the
2584 end of the buffer to safety-stop C-string reads from it. */
2586 if (!(smtp_inbuffer = US malloc(IN_BUFFER_SIZE)))
2587 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "malloc() failed for SMTP input buffer");
2588 smtp_inbuffer[IN_BUFFER_SIZE-1] = '\0';
2590 receive_getc = smtp_getc;
2591 receive_getbuf = smtp_getbuf;
2592 receive_get_cache = smtp_get_cache;
2593 receive_hasc = smtp_hasc;
2594 receive_ungetc = smtp_ungetc;
2595 receive_feof = smtp_feof;
2596 receive_ferror = smtp_ferror;
2597 receive_smtp_buffered = smtp_buffered;
2598 lwr_receive_getc = NULL;
2599 lwr_receive_getbuf = NULL;
2600 lwr_receive_hasc = NULL;
2601 lwr_receive_ungetc = NULL;
2602 smtp_inptr = smtp_inend = smtp_inbuffer;
2603 smtp_had_eof = smtp_had_error = 0;
2605 /* Set up the message size limit; this may be host-specific */
2607 thismessage_size_limit = expand_string_integer(message_size_limit, TRUE);
2608 if (expand_string_message)
2610 if (thismessage_size_limit == -1)
2611 log_write(0, LOG_MAIN|LOG_PANIC, "unable to expand message_size_limit: "
2612 "%s", expand_string_message);
2614 log_write(0, LOG_MAIN|LOG_PANIC, "invalid message_size_limit: "
2615 "%s", expand_string_message);
2616 smtp_closedown(US"Temporary local problem - please try later");
2620 /* When a message is input locally via the -bs or -bS options, sender_host_
2621 unknown is set unless -oMa was used to force an IP address, in which case it
2622 is checked like a real remote connection. When -bs is used from inetd, this
2623 flag is not set, causing the sending host to be checked. The code that deals
2624 with IP source routing (if configured) is never required for -bs or -bS and
2625 the flag sender_host_notsocket is used to suppress it.
2627 If smtp_accept_max and smtp_accept_reserve are set, keep some connections in
2628 reserve for certain hosts and/or networks. */
2630 if (!f.sender_host_unknown)
2633 BOOL reserved_host = FALSE;
2635 /* Look up IP options (source routing info) on the socket if this is not an
2636 -oMa "host", and if any are found, log them and drop the connection.
2638 Linux (and others now, see below) is different to everyone else, so there
2639 has to be some conditional compilation here. Versions of Linux before 2.1.15
2640 used a structure whose name was "options". Somebody finally realized that
2641 this name was silly, and it got changed to "ip_options". I use the
2642 newer name here, but there is a fudge in the script that sets up os.h
2643 to define a macro in older Linux systems.
2645 Sigh. Linux is a fast-moving target. Another generation of Linux uses
2646 glibc 2, which has chosen ip_opts for the structure name. This is now
2647 really a glibc thing rather than a Linux thing, so the condition name
2648 has been changed to reflect this. It is relevant also to GNU/Hurd.
2650 Mac OS 10.x (Darwin) is like the later glibc versions, but without the
2651 setting of the __GLIBC__ macro, so we can't detect it automatically. There's
2652 a special macro defined in the os.h file.
2654 Some DGUX versions on older hardware appear not to support IP options at
2655 all, so there is now a general macro which can be set to cut out this
2658 How to do this properly in IPv6 is not yet known. */
2660 #if !HAVE_IPV6 && !defined(NO_IP_OPTIONS)
2662 #ifdef GLIBC_IP_OPTIONS
2663 #if (!defined __GLIBC__) || (__GLIBC__ < 2)
2668 #elif defined DARWIN_IP_OPTIONS
2674 if (!host_checking && !f.sender_host_notsocket)
2677 EXIM_SOCKLEN_T optlen = sizeof(struct ip_options) + MAX_IPOPTLEN;
2678 struct ip_options *ipopt = store_get(optlen, FALSE);
2680 struct ip_opts ipoptblock;
2681 struct ip_opts *ipopt = &ipoptblock;
2682 EXIM_SOCKLEN_T optlen = sizeof(ipoptblock);
2684 struct ipoption ipoptblock;
2685 struct ipoption *ipopt = &ipoptblock;
2686 EXIM_SOCKLEN_T optlen = sizeof(ipoptblock);
2689 /* Occasional genuine failures of getsockopt() have been seen - for
2690 example, "reset by peer". Therefore, just log and give up on this
2691 call, unless the error is ENOPROTOOPT. This error is given by systems
2692 that have the interfaces but not the mechanism - e.g. GNU/Hurd at the time
2693 of writing. So for that error, carry on - we just can't do an IP options
2696 DEBUG(D_receive) debug_printf("checking for IP options\n");
2698 if (getsockopt(fileno(smtp_out), IPPROTO_IP, IP_OPTIONS, US (ipopt),
2701 if (errno != ENOPROTOOPT)
2703 log_write(0, LOG_MAIN, "getsockopt() failed from %s: %s",
2704 host_and_ident(FALSE), strerror(errno));
2705 smtp_printf("451 SMTP service not available\r\n", FALSE);
2710 /* Deal with any IP options that are set. On the systems I have looked at,
2711 the value of MAX_IPOPTLEN has been 40, meaning that there should never be
2712 more logging data than will fit in big_buffer. Nevertheless, after somebody
2713 questioned this code, I've added in some paranoid checking. */
2715 else if (optlen > 0)
2717 uschar *p = big_buffer;
2718 uschar *pend = big_buffer + big_buffer_size;
2721 struct in_addr addr;
2724 uschar *optstart = US (ipopt->__data);
2726 uschar *optstart = US (ipopt->ip_opts);
2728 uschar *optstart = US (ipopt->ipopt_list);
2731 DEBUG(D_receive) debug_printf("IP options exist\n");
2733 Ustrcpy(p, "IP options on incoming call:");
2736 for (uschar * opt = optstart; opt && opt < US (ipopt) + optlen; )
2749 if (!string_format(p, pend-p, " %s [@%s",
2750 (*opt == IPOPT_SSRR)? "SSRR" : "LSRR",
2752 inet_ntoa(*((struct in_addr *)(&(ipopt->faddr))))))
2754 inet_ntoa(ipopt->ip_dst)))
2756 inet_ntoa(ipopt->ipopt_dst)))
2764 optcount = (opt[1] - 3) / sizeof(struct in_addr);
2766 while (optcount-- > 0)
2768 memcpy(&addr, adptr, sizeof(addr));
2769 if (!string_format(p, pend - p - 1, "%s%s",
2770 (optcount == 0)? ":" : "@", inet_ntoa(addr)))
2776 adptr += sizeof(struct in_addr);
2784 if (pend - p < 4 + 3*opt[1]) { opt = NULL; break; }
2787 for (int i = 0; i < opt[1]; i++)
2788 p += sprintf(CS p, "%2.2x ", opt[i]);
2796 log_write(0, LOG_MAIN, "%s", big_buffer);
2798 /* Refuse any call with IP options. This is what tcpwrappers 7.5 does. */
2800 log_write(0, LOG_MAIN|LOG_REJECT,
2801 "connection from %s refused (IP options)", host_and_ident(FALSE));
2803 smtp_printf("554 SMTP service not available\r\n", FALSE);
2807 /* Length of options = 0 => there are no options */
2809 else DEBUG(D_receive) debug_printf("no IP options found\n");
2811 #endif /* HAVE_IPV6 && !defined(NO_IP_OPTIONS) */
2813 /* Set keep-alive in socket options. The option is on by default. This
2814 setting is an attempt to get rid of some hanging connections that stick in
2815 read() when the remote end (usually a dialup) goes away. */
2817 if (smtp_accept_keepalive && !f.sender_host_notsocket)
2818 ip_keepalive(fileno(smtp_out), sender_host_address, FALSE);
2820 /* If the current host matches host_lookup, set the name by doing a
2821 reverse lookup. On failure, sender_host_name will be NULL and
2822 host_lookup_failed will be TRUE. This may or may not be serious - optional
2825 if (verify_check_host(&host_lookup) == OK)
2827 (void)host_name_lookup();
2828 host_build_sender_fullhost();
2831 /* Delay this until we have the full name, if it is looked up. */
2833 set_process_info("handling incoming connection from %s",
2834 host_and_ident(FALSE));
2836 /* Expand smtp_receive_timeout, if needed */
2838 if (smtp_receive_timeout_s)
2841 if ( !(exp = expand_string(smtp_receive_timeout_s))
2843 || (smtp_receive_timeout = readconf_readtime(exp, 0, FALSE)) < 0
2845 log_write(0, LOG_MAIN|LOG_PANIC,
2846 "bad value for smtp_receive_timeout: '%s'", exp ? exp : US"");
2849 /* Test for explicit connection rejection */
2851 if (verify_check_host(&host_reject_connection) == OK)
2853 log_write(L_connection_reject, LOG_MAIN|LOG_REJECT, "refused connection "
2854 "from %s (host_reject_connection)", host_and_ident(FALSE));
2855 smtp_printf("554 SMTP service not available\r\n", FALSE);
2859 /* Test with TCP Wrappers if so configured. There is a problem in that
2860 hosts_ctl() returns 0 (deny) under a number of system failure circumstances,
2861 such as disks dying. In these cases, it is desirable to reject with a 4xx
2862 error instead of a 5xx error. There isn't a "right" way to detect such
2863 problems. The following kludge is used: errno is zeroed before calling
2864 hosts_ctl(). If the result is "reject", a 5xx error is given only if the
2865 value of errno is 0 or ENOENT (which happens if /etc/hosts.{allow,deny} does
2868 #ifdef USE_TCP_WRAPPERS
2870 if (!(tcp_wrappers_name = expand_string(tcp_wrappers_daemon_name)))
2871 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "Expansion of \"%s\" "
2872 "(tcp_wrappers_name) failed: %s", string_printing(tcp_wrappers_name),
2873 expand_string_message);
2875 if (!hosts_ctl(tcp_wrappers_name,
2876 sender_host_name ? CS sender_host_name : STRING_UNKNOWN,
2877 sender_host_address ? CS sender_host_address : STRING_UNKNOWN,
2878 sender_ident ? CS sender_ident : STRING_UNKNOWN))
2880 if (errno == 0 || errno == ENOENT)
2882 HDEBUG(D_receive) debug_printf("tcp wrappers rejection\n");
2883 log_write(L_connection_reject,
2884 LOG_MAIN|LOG_REJECT, "refused connection from %s "
2885 "(tcp wrappers)", host_and_ident(FALSE));
2886 smtp_printf("554 SMTP service not available\r\n", FALSE);
2890 int save_errno = errno;
2891 HDEBUG(D_receive) debug_printf("tcp wrappers rejected with unexpected "
2892 "errno value %d\n", save_errno);
2893 log_write(L_connection_reject,
2894 LOG_MAIN|LOG_REJECT, "temporarily refused connection from %s "
2895 "(tcp wrappers errno=%d)", host_and_ident(FALSE), save_errno);
2896 smtp_printf("451 Temporary local problem - please try later\r\n", FALSE);
2902 /* Check for reserved slots. The value of smtp_accept_count has already been
2903 incremented to include this process. */
2905 if (smtp_accept_max > 0 &&
2906 smtp_accept_count > smtp_accept_max - smtp_accept_reserve)
2908 if ((rc = verify_check_host(&smtp_reserve_hosts)) != OK)
2910 log_write(L_connection_reject,
2911 LOG_MAIN, "temporarily refused connection from %s: not in "
2912 "reserve list: connected=%d max=%d reserve=%d%s",
2913 host_and_ident(FALSE), smtp_accept_count - 1, smtp_accept_max,
2914 smtp_accept_reserve, (rc == DEFER)? " (lookup deferred)" : "");
2915 smtp_printf("421 %s: Too many concurrent SMTP connections; "
2916 "please try again later\r\n", FALSE, smtp_active_hostname);
2919 reserved_host = TRUE;
2922 /* If a load level above which only messages from reserved hosts are
2923 accepted is set, check the load. For incoming calls via the daemon, the
2924 check is done in the superior process if there are no reserved hosts, to
2925 save a fork. In all cases, the load average will already be available
2926 in a global variable at this point. */
2928 if (smtp_load_reserve >= 0 &&
2929 load_average > smtp_load_reserve &&
2931 verify_check_host(&smtp_reserve_hosts) != OK)
2933 log_write(L_connection_reject,
2934 LOG_MAIN, "temporarily refused connection from %s: not in "
2935 "reserve list and load average = %.2f", host_and_ident(FALSE),
2936 (double)load_average/1000.0);
2937 smtp_printf("421 %s: Too much load; please try again later\r\n", FALSE,
2938 smtp_active_hostname);
2942 /* Determine whether unqualified senders or recipients are permitted
2943 for this host. Unfortunately, we have to do this every time, in order to
2944 set the flags so that they can be inspected when considering qualifying
2945 addresses in the headers. For a site that permits no qualification, this
2946 won't take long, however. */
2948 f.allow_unqualified_sender =
2949 verify_check_host(&sender_unqualified_hosts) == OK;
2951 f.allow_unqualified_recipient =
2952 verify_check_host(&recipient_unqualified_hosts) == OK;
2954 /* Determine whether HELO/EHLO is required for this host. The requirement
2955 can be hard or soft. */
2957 fl.helo_verify_required = verify_check_host(&helo_verify_hosts) == OK;
2958 if (!fl.helo_verify_required)
2959 fl.helo_verify = verify_check_host(&helo_try_verify_hosts) == OK;
2961 /* Determine whether this hosts is permitted to send syntactic junk
2962 after a HELO or EHLO command. */
2964 fl.helo_accept_junk = verify_check_host(&helo_accept_junk_hosts) == OK;
2967 /* For batch SMTP input we are now done. */
2969 if (smtp_batched_input) return TRUE;
2971 /* If valid Proxy Protocol source is connecting, set up session.
2972 Failure will not allow any SMTP function other than QUIT. */
2974 #ifdef SUPPORT_PROXY
2975 proxy_session = FALSE;
2976 f.proxy_session_failed = FALSE;
2977 if (check_proxy_protocol_host())
2978 setup_proxy_protocol_host();
2981 /* Start up TLS if tls_on_connect is set. This is for supporting the legacy
2982 smtps port for use with older style SSL MTAs. */
2985 if (tls_in.on_connect)
2987 if (tls_server_start(&user_msg) != OK)
2988 return smtp_log_tls_fail(user_msg);
2989 cmd_list[CMD_LIST_TLS_AUTH].is_mail_cmd = TRUE;
2993 /* Run the connect ACL if it exists */
2996 if (acl_smtp_connect)
2999 if ((rc = acl_check(ACL_WHERE_CONNECT, NULL, acl_smtp_connect, &user_msg,
3002 (void) smtp_handle_acl_fail(ACL_WHERE_CONNECT, rc, user_msg, log_msg);
3007 /* Output the initial message for a two-way SMTP connection. It may contain
3008 newlines, which then cause a multi-line response to be given. */
3010 code = US"220"; /* Default status code */
3011 esc = US""; /* Default extended status code */
3012 esclen = 0; /* Length of esc */
3016 if (!(s = expand_string(smtp_banner)))
3017 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "Expansion of \"%s\" (smtp_banner) "
3018 "failed: %s", smtp_banner, expand_string_message);
3024 smtp_message_code(&code, &codelen, &s, NULL, TRUE);
3028 esclen = codelen - 4;
3032 /* Remove any terminating newlines; might as well remove trailing space too */
3035 while (p > s && isspace(p[-1])) p--;
3036 s = string_copyn(s, p-s);
3038 /* It seems that CC:Mail is braindead, and assumes that the greeting message
3039 is all contained in a single IP packet. The original code wrote out the
3040 greeting using several calls to fprint/fputc, and on busy servers this could
3041 cause it to be split over more than one packet - which caused CC:Mail to fall
3042 over when it got the second part of the greeting after sending its first
3043 command. Sigh. To try to avoid this, build the complete greeting message
3044 first, and output it in one fell swoop. This gives a better chance of it
3045 ending up as a single packet. */
3047 ss = string_get(256);
3050 do /* At least once, in case we have an empty string */
3053 uschar *linebreak = Ustrchr(p, '\n');
3054 ss = string_catn(ss, code, 3);
3058 ss = string_catn(ss, US" ", 1);
3062 len = linebreak - p;
3063 ss = string_catn(ss, US"-", 1);
3065 ss = string_catn(ss, esc, esclen);
3066 ss = string_catn(ss, p, len);
3067 ss = string_catn(ss, US"\r\n", 2);
3073 /* Before we write the banner, check that there is no input pending, unless
3074 this synchronisation check is disabled. */
3076 #ifndef DISABLE_PIPE_CONNECT
3077 fl.pipe_connect_acceptable =
3078 sender_host_address && verify_check_host(&pipe_connect_advertise_hosts) == OK;
3081 if (fl.pipe_connect_acceptable)
3082 f.smtp_in_early_pipe_used = TRUE;
3088 unsigned n = smtp_inend - smtp_inptr;
3089 if (n > 128) n = 128;
3091 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP protocol "
3092 "synchronization error (input sent without waiting for greeting): "
3093 "rejected connection from %s input=\"%s\"", host_and_ident(TRUE),
3094 string_printing(string_copyn(smtp_inptr, n)));
3095 smtp_printf("554 SMTP synchronization error\r\n", FALSE);
3099 /* Now output the banner */
3100 /*XXX the ehlo-resp code does its own tls/nontls bit. Maybe subroutine that? */
3103 #ifndef DISABLE_PIPE_CONNECT
3104 fl.pipe_connect_acceptable && pipeline_connect_sends(),
3108 string_from_gstring(ss));
3110 /* Attempt to see if we sent the banner before the last ACK of the 3-way
3111 handshake arrived. If so we must have managed a TFO. */
3114 if (sender_host_address && !f.sender_host_notsocket) tfo_in_check();
3124 /*************************************************
3125 * Handle SMTP syntax and protocol errors *
3126 *************************************************/
3128 /* Write to the log for SMTP syntax errors in incoming commands, if configured
3129 to do so. Then transmit the error response. The return value depends on the
3130 number of syntax and protocol errors in this SMTP session.
3133 type error type, given as a log flag bit
3134 code response code; <= 0 means don't send a response
3135 data data to reflect in the response (can be NULL)
3136 errmess the error message
3138 Returns: -1 limit of syntax/protocol errors NOT exceeded
3139 +1 limit of syntax/protocol errors IS exceeded
3141 These values fit in with the values of the "done" variable in the main
3142 processing loop in smtp_setup_msg(). */
3145 synprot_error(int type, int code, uschar *data, uschar *errmess)
3149 log_write(type, LOG_MAIN, "SMTP %s error in \"%s\" %s %s",
3150 type == L_smtp_syntax_error ? "syntax" : "protocol",
3151 string_printing(smtp_cmd_buffer), host_and_ident(TRUE), errmess);
3153 if (++synprot_error_count > smtp_max_synprot_errors)
3156 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
3157 "syntax or protocol errors (last command was \"%s\", %s)",
3158 host_and_ident(FALSE), string_printing(smtp_cmd_buffer),
3159 string_from_gstring(s_connhad_log(NULL))
3165 smtp_printf("%d%c%s%s%s\r\n", FALSE, code, yield == 1 ? '-' : ' ',
3166 data ? data : US"", data ? US": " : US"", errmess);
3168 smtp_printf("%d Too many syntax or protocol errors\r\n", FALSE, code);
3177 /*************************************************
3178 * Send SMTP response, possibly multiline *
3179 *************************************************/
3181 /* There are, it seems, broken clients out there that cannot handle multiline
3182 responses. If no_multiline_responses is TRUE (it can be set from an ACL), we
3183 output nothing for non-final calls, and only the first line for anything else.
3186 code SMTP code, may involve extended status codes
3187 codelen length of smtp code; if > 4 there's an ESC
3188 final FALSE if the last line isn't the final line
3189 msg message text, possibly containing newlines
3195 smtp_respond(uschar* code, int codelen, BOOL final, uschar *msg)
3200 if (!final && f.no_multiline_responses) return;
3205 esclen = codelen - 4;
3208 /* If this is the first output for a (non-batch) RCPT command, see if all RCPTs
3209 have had the same. Note: this code is also present in smtp_printf(). It would
3210 be tidier to have it only in one place, but when it was added, it was easier to
3211 do it that way, so as not to have to mess with the code for the RCPT command,
3212 which sometimes uses smtp_printf() and sometimes smtp_respond(). */
3214 if (fl.rcpt_in_progress)
3216 if (!rcpt_smtp_response)
3217 rcpt_smtp_response = string_copy(msg);
3218 else if (fl.rcpt_smtp_response_same &&
3219 Ustrcmp(rcpt_smtp_response, msg) != 0)
3220 fl.rcpt_smtp_response_same = FALSE;
3221 fl.rcpt_in_progress = FALSE;
3224 /* Now output the message, splitting it up into multiple lines if necessary.
3225 We only handle pipelining these responses as far as nonfinal/final groups,
3226 not the whole MAIL/RCPT/DATA response set. */
3230 uschar *nl = Ustrchr(msg, '\n');
3233 smtp_printf("%.3s%c%.*s%s\r\n", !final, code, final ? ' ':'-', esclen, esc, msg);
3236 else if (nl[1] == 0 || f.no_multiline_responses)
3238 smtp_printf("%.3s%c%.*s%.*s\r\n", !final, code, final ? ' ':'-', esclen, esc,
3239 (int)(nl - msg), msg);
3244 smtp_printf("%.3s-%.*s%.*s\r\n", TRUE, code, esclen, esc, (int)(nl - msg), msg);
3246 Uskip_whitespace(&msg);
3254 /*************************************************
3255 * Parse user SMTP message *
3256 *************************************************/
3258 /* This function allows for user messages overriding the response code details
3259 by providing a suitable response code string at the start of the message
3260 user_msg. Check the message for starting with a response code and optionally an
3261 extended status code. If found, check that the first digit is valid, and if so,
3262 change the code pointer and length to use the replacement. An invalid code
3263 causes a panic log; in this case, if the log messages is the same as the user
3264 message, we must also adjust the value of the log message to show the code that
3265 is actually going to be used (the original one).
3267 This function is global because it is called from receive.c as well as within
3270 Note that the code length returned includes the terminating whitespace
3271 character, which is always included in the regex match.
3274 code SMTP code, may involve extended status codes
3275 codelen length of smtp code; if > 4 there's an ESC
3277 log_msg optional log message, to be adjusted with the new SMTP code
3278 check_valid if true, verify the response code
3284 smtp_message_code(uschar **code, int *codelen, uschar **msg, uschar **log_msg,
3290 if (!msg || !*msg || !regex_match(regex_smtp_code, *msg, -1, &match))
3293 len = Ustrlen(match);
3294 if (check_valid && (*msg)[0] != (*code)[0])
3296 log_write(0, LOG_MAIN|LOG_PANIC, "configured error code starts with "
3297 "incorrect digit (expected %c) in \"%s\"", (*code)[0], *msg);
3298 if (log_msg && *log_msg == *msg)
3299 *log_msg = string_sprintf("%s %s", *code, *log_msg + len);
3304 *codelen = len; /* Includes final space */
3306 *msg += len; /* Chop the code off the message */
3313 /*************************************************
3314 * Handle an ACL failure *
3315 *************************************************/
3317 /* This function is called when acl_check() fails. As well as calls from within
3318 this module, it is called from receive.c for an ACL after DATA. It sorts out
3319 logging the incident, and sends the error response. A message containing
3320 newlines is turned into a multiline SMTP response, but for logging, only the
3323 There's a table of default permanent failure response codes to use in
3324 globals.c, along with the table of names. VFRY is special. Despite RFC1123 it
3325 defaults disabled in Exim. However, discussion in connection with RFC 821bis
3326 (aka RFC 2821) has concluded that the response should be 252 in the disabled
3327 state, because there are broken clients that try VRFY before RCPT. A 5xx
3328 response should be given only when the address is positively known to be
3329 undeliverable. Sigh. We return 252 if there is no VRFY ACL or it provides
3330 no explicit code, but if there is one we let it know best.
3331 Also, for ETRN, 458 is given on refusal, and for AUTH, 503.
3333 From Exim 4.63, it is possible to override the response code details by
3334 providing a suitable response code string at the start of the message provided
3335 in user_msg. The code's first digit is checked for validity.
3338 where where the ACL was called from
3340 user_msg a message that can be included in an SMTP response
3341 log_msg a message for logging
3343 Returns: 0 in most cases
3344 2 if the failure code was FAIL_DROP, in which case the
3345 SMTP connection should be dropped (this value fits with the
3346 "done" variable in smtp_setup_msg() below)
3350 smtp_handle_acl_fail(int where, int rc, uschar *user_msg, uschar *log_msg)
3352 BOOL drop = rc == FAIL_DROP;
3356 uschar *sender_info = US"";
3359 if (drop) rc = FAIL;
3361 /* Set the default SMTP code, and allow a user message to change it. */
3363 smtp_code = rc == FAIL ? acl_wherecodes[where] : US"451";
3364 smtp_message_code(&smtp_code, &codelen, &user_msg, &log_msg,
3365 where != ACL_WHERE_VRFY);
3367 /* We used to have sender_address here; however, there was a bug that was not
3368 updating sender_address after a rewrite during a verify. When this bug was
3369 fixed, sender_address at this point became the rewritten address. I'm not sure
3370 this is what should be logged, so I've changed to logging the unrewritten
3371 address to retain backward compatibility. */
3375 #ifdef WITH_CONTENT_SCAN
3376 case ACL_WHERE_MIME: what = US"during MIME ACL checks"; break;
3378 case ACL_WHERE_PREDATA: what = US"DATA"; break;
3379 case ACL_WHERE_DATA: what = US"after DATA"; break;
3380 #ifndef DISABLE_PRDR
3381 case ACL_WHERE_PRDR: what = US"after DATA PRDR"; break;
3385 uschar * place = smtp_cmd_data ? smtp_cmd_data : US"in \"connect\" ACL";
3388 if (where == ACL_WHERE_AUTH) /* avoid logging auth creds */
3391 for (s = smtp_cmd_data; *s && !isspace(*s); ) s++;
3392 lim = s - smtp_cmd_data; /* atop after method */
3394 what = string_sprintf("%s %.*s", acl_wherenames[where], lim, place);
3399 case ACL_WHERE_RCPT:
3400 case ACL_WHERE_DATA:
3401 #ifdef WITH_CONTENT_SCAN
3402 case ACL_WHERE_MIME:
3404 sender_info = string_sprintf("F=<%s>%s%s%s%s ",
3405 sender_address_unrewritten ? sender_address_unrewritten : sender_address,
3406 sender_host_authenticated ? US" A=" : US"",
3407 sender_host_authenticated ? sender_host_authenticated : US"",
3408 sender_host_authenticated && authenticated_id ? US":" : US"",
3409 sender_host_authenticated && authenticated_id ? authenticated_id : US""
3414 /* If there's been a sender verification failure with a specific message, and
3415 we have not sent a response about it yet, do so now, as a preliminary line for
3416 failures, but not defers. However, always log it for defer, and log it for fail
3417 unless the sender_verify_fail log selector has been turned off. */
3419 if (sender_verified_failed &&
3420 !testflag(sender_verified_failed, af_sverify_told))
3422 BOOL save_rcpt_in_progress = fl.rcpt_in_progress;
3423 fl.rcpt_in_progress = FALSE; /* So as not to treat these as the error */
3425 setflag(sender_verified_failed, af_sverify_told);
3427 if (rc != FAIL || LOGGING(sender_verify_fail))
3428 log_write(0, LOG_MAIN|LOG_REJECT, "%s sender verify %s for <%s>%s",
3429 host_and_ident(TRUE),
3430 ((sender_verified_failed->special_action & 255) == DEFER)? "defer":"fail",
3431 sender_verified_failed->address,
3432 (sender_verified_failed->message == NULL)? US"" :
3433 string_sprintf(": %s", sender_verified_failed->message));
3435 if (rc == FAIL && sender_verified_failed->user_message)
3436 smtp_respond(smtp_code, codelen, FALSE, string_sprintf(
3437 testflag(sender_verified_failed, af_verify_pmfail)?
3438 "Postmaster verification failed while checking <%s>\n%s\n"
3439 "Several RFCs state that you are required to have a postmaster\n"
3440 "mailbox for each mail domain. This host does not accept mail\n"
3441 "from domains whose servers reject the postmaster address."
3443 testflag(sender_verified_failed, af_verify_nsfail)?
3444 "Callback setup failed while verifying <%s>\n%s\n"
3445 "The initial connection, or a HELO or MAIL FROM:<> command was\n"
3446 "rejected. Refusing MAIL FROM:<> does not help fight spam, disregards\n"
3447 "RFC requirements, and stops you from receiving standard bounce\n"
3448 "messages. This host does not accept mail from domains whose servers\n"
3451 "Verification failed for <%s>\n%s",
3452 sender_verified_failed->address,
3453 sender_verified_failed->user_message));
3455 fl.rcpt_in_progress = save_rcpt_in_progress;
3458 /* Sort out text for logging */
3460 log_msg = log_msg ? string_sprintf(": %s", log_msg) : US"";
3461 if ((lognl = Ustrchr(log_msg, '\n'))) *lognl = 0;
3463 /* Send permanent failure response to the command, but the code used isn't
3464 always a 5xx one - see comments at the start of this function. If the original
3465 rc was FAIL_DROP we drop the connection and yield 2. */
3468 smtp_respond(smtp_code, codelen, TRUE,
3469 user_msg ? user_msg : US"Administrative prohibition");
3471 /* Send temporary failure response to the command. Don't give any details,
3472 unless acl_temp_details is set. This is TRUE for a callout defer, a "defer"
3473 verb, and for a header verify when smtp_return_error_details is set.
3475 This conditional logic is all somewhat of a mess because of the odd
3476 interactions between temp_details and return_error_details. One day it should
3477 be re-implemented in a tidier fashion. */
3480 if (f.acl_temp_details && user_msg)
3482 if ( smtp_return_error_details
3483 && sender_verified_failed
3484 && sender_verified_failed->message
3486 smtp_respond(smtp_code, codelen, FALSE, sender_verified_failed->message);
3488 smtp_respond(smtp_code, codelen, TRUE, user_msg);
3491 smtp_respond(smtp_code, codelen, TRUE,
3492 US"Temporary local problem - please try later");
3494 /* Log the incident to the logs that are specified by log_reject_target
3495 (default main, reject). This can be empty to suppress logging of rejections. If
3496 the connection is not forcibly to be dropped, return 0. Otherwise, log why it
3497 is closing if required and return 2. */
3499 if (log_reject_target != 0)
3502 gstring * g = s_tlslog(NULL);
3503 uschar * tls = string_from_gstring(g);
3504 if (!tls) tls = US"";
3506 uschar * tls = US"";
3508 log_write(where == ACL_WHERE_CONNECT ? L_connection_reject : 0,
3509 log_reject_target, "%s%s%s %s%srejected %s%s",
3510 LOGGING(dnssec) && sender_host_dnssec ? US" DS" : US"",
3511 host_and_ident(TRUE),
3514 rc == FAIL ? US"" : US"temporarily ",
3518 if (!drop) return 0;
3520 log_write(L_smtp_connection, LOG_MAIN, "%s closed by DROP in ACL",
3521 smtp_get_connection_info());
3523 /* Run the not-quit ACL, but without any custom messages. This should not be a
3524 problem, because we get here only if some other ACL has issued "drop", and
3525 in that case, *its* custom messages will have been used above. */
3527 smtp_notquit_exit(US"acl-drop", NULL, NULL);
3534 /*************************************************
3535 * Handle SMTP exit when QUIT is not given *
3536 *************************************************/
3538 /* This function provides a logging/statistics hook for when an SMTP connection
3539 is dropped on the floor or the other end goes away. It's a global function
3540 because it's called from receive.c as well as this module. As well as running
3541 the NOTQUIT ACL, if there is one, this function also outputs a final SMTP
3542 response, either with a custom message from the ACL, or using a default. There
3543 is one case, however, when no message is output - after "drop". In that case,
3544 the ACL that obeyed "drop" has already supplied the custom message, and NULL is
3545 passed to this function.
3547 In case things go wrong while processing this function, causing an error that
3548 may re-enter this function, there is a recursion check.
3551 reason What $smtp_notquit_reason will be set to in the ACL;
3552 if NULL, the ACL is not run
3553 code The error code to return as part of the response
3554 defaultrespond The default message if there's no user_msg
3560 smtp_notquit_exit(uschar *reason, uschar *code, uschar *defaultrespond, ...)
3563 uschar *user_msg = NULL;
3564 uschar *log_msg = NULL;
3566 /* Check for recursive call */
3568 if (fl.smtp_exit_function_called)
3570 log_write(0, LOG_PANIC, "smtp_notquit_exit() called more than once (%s)",
3574 fl.smtp_exit_function_called = TRUE;
3576 /* Call the not-QUIT ACL, if there is one, unless no reason is given. */
3578 if (acl_smtp_notquit && reason)
3580 smtp_notquit_reason = reason;
3581 if ((rc = acl_check(ACL_WHERE_NOTQUIT, NULL, acl_smtp_notquit, &user_msg,
3582 &log_msg)) == ERROR)
3583 log_write(0, LOG_MAIN|LOG_PANIC, "ACL for not-QUIT returned ERROR: %s",
3587 /* If the connection was dropped, we certainly are no longer talking TLS */
3588 tls_in.active.sock = -1;
3590 /* Write an SMTP response if we are expected to give one. As the default
3591 responses are all internal, they should be reasonable size. */
3593 if (code && defaultrespond)
3596 smtp_respond(code, 3, TRUE, user_msg);
3602 va_start(ap, defaultrespond);
3603 g = string_vformat(NULL, SVFMT_EXTEND|SVFMT_REBUFFER, CS defaultrespond, ap);
3605 smtp_printf("%s %s\r\n", FALSE, code, string_from_gstring(g));
3614 /*************************************************
3615 * Verify HELO argument *
3616 *************************************************/
3618 /* This function is called if helo_verify_hosts or helo_try_verify_hosts is
3619 matched. It is also called from ACL processing if verify = helo is used and
3620 verification was not previously tried (i.e. helo_try_verify_hosts was not
3621 matched). The result of its processing is to set helo_verified and
3622 helo_verify_failed. These variables should both be FALSE for this function to
3625 Note that EHLO/HELO is legitimately allowed to quote an address literal. Allow
3626 for IPv6 ::ffff: literals.
3629 Returns: TRUE if testing was completed;
3630 FALSE on a temporary failure
3634 smtp_verify_helo(void)
3638 HDEBUG(D_receive) debug_printf("verifying EHLO/HELO argument \"%s\"\n",
3641 if (sender_helo_name == NULL)
3643 HDEBUG(D_receive) debug_printf("no EHLO/HELO command was issued\n");
3646 /* Deal with the case of -bs without an IP address */
3648 else if (sender_host_address == NULL)
3650 HDEBUG(D_receive) debug_printf("no client IP address: assume success\n");
3651 f.helo_verified = TRUE;
3654 /* Deal with the more common case when there is a sending IP address */
3656 else if (sender_helo_name[0] == '[')
3658 f.helo_verified = Ustrncmp(sender_helo_name+1, sender_host_address,
3659 Ustrlen(sender_host_address)) == 0;
3662 if (!f.helo_verified)
3664 if (strncmpic(sender_host_address, US"::ffff:", 7) == 0)
3665 f.helo_verified = Ustrncmp(sender_helo_name + 1,
3666 sender_host_address + 7, Ustrlen(sender_host_address) - 7) == 0;
3671 { if (f.helo_verified) debug_printf("matched host address\n"); }
3674 /* Do a reverse lookup if one hasn't already given a positive or negative
3675 response. If that fails, or the name doesn't match, try checking with a forward
3680 if (sender_host_name == NULL && !host_lookup_failed)
3681 yield = host_name_lookup() != DEFER;
3683 /* If a host name is known, check it and all its aliases. */
3685 if (sender_host_name)
3686 if ((f.helo_verified = strcmpic(sender_host_name, sender_helo_name) == 0))
3688 sender_helo_dnssec = sender_host_dnssec;
3689 HDEBUG(D_receive) debug_printf("matched host name\n");
3693 uschar **aliases = sender_host_aliases;
3695 if ((f.helo_verified = strcmpic(*aliases++, sender_helo_name) == 0))
3697 sender_helo_dnssec = sender_host_dnssec;
3701 HDEBUG(D_receive) if (f.helo_verified)
3702 debug_printf("matched alias %s\n", *(--aliases));
3705 /* Final attempt: try a forward lookup of the helo name */
3707 if (!f.helo_verified)
3711 {.name = sender_helo_name, .address = NULL, .mx = MX_NONE, .next = NULL};
3713 {.request = US"*", .require = US""};
3715 HDEBUG(D_receive) debug_printf("getting IP address for %s\n",
3717 rc = host_find_bydns(&h, NULL, HOST_FIND_BY_A | HOST_FIND_BY_AAAA,
3718 NULL, NULL, NULL, &d, NULL, NULL);
3719 if (rc == HOST_FOUND || rc == HOST_FOUND_LOCAL)
3720 for (host_item * hh = &h; hh; hh = hh->next)
3721 if (Ustrcmp(hh->address, sender_host_address) == 0)
3723 f.helo_verified = TRUE;
3724 if (h.dnssec == DS_YES) sender_helo_dnssec = TRUE;
3726 debug_printf("IP address for %s matches calling address\n"
3727 "Forward DNS security status: %sverified\n",
3728 sender_helo_name, sender_helo_dnssec ? "" : "un");
3734 if (!f.helo_verified) f.helo_verify_failed = TRUE; /* We've tried ... */
3741 /*************************************************
3742 * Send user response message *
3743 *************************************************/
3745 /* This function is passed a default response code and a user message. It calls
3746 smtp_message_code() to check and possibly modify the response code, and then
3747 calls smtp_respond() to transmit the response. I put this into a function
3748 just to avoid a lot of repetition.
3751 code the response code
3752 user_msg the user message
3758 smtp_user_msg(uschar *code, uschar *user_msg)
3761 smtp_message_code(&code, &len, &user_msg, NULL, TRUE);
3762 smtp_respond(code, len, TRUE, user_msg);
3768 smtp_in_auth(auth_instance *au, uschar ** s, uschar ** ss)
3770 const uschar *set_id = NULL;
3773 /* Run the checking code, passing the remainder of the command line as
3774 data. Initials the $auth<n> variables as empty. Initialize $0 empty and set
3775 it as the only set numerical variable. The authenticator may set $auth<n>
3776 and also set other numeric variables. The $auth<n> variables are preferred
3777 nowadays; the numerical variables remain for backwards compatibility.
3779 Afterwards, have a go at expanding the set_id string, even if
3780 authentication failed - for bad passwords it can be useful to log the
3781 userid. On success, require set_id to expand and exist, and put it in
3782 authenticated_id. Save this in permanent store, as the working store gets
3783 reset at HELO, RSET, etc. */
3785 for (int i = 0; i < AUTH_VARS; i++) auth_vars[i] = NULL;
3787 expand_nlength[0] = 0; /* $0 contains nothing */
3789 rc = (au->info->servercode)(au, smtp_cmd_data);
3790 if (au->set_id) set_id = expand_string(au->set_id);
3791 expand_nmax = -1; /* Reset numeric variables */
3792 for (int i = 0; i < AUTH_VARS; i++) auth_vars[i] = NULL; /* Reset $auth<n> */
3794 /* The value of authenticated_id is stored in the spool file and printed in
3795 log lines. It must not contain binary zeros or newline characters. In
3796 normal use, it never will, but when playing around or testing, this error
3797 can (did) happen. To guard against this, ensure that the id contains only
3798 printing characters. */
3800 if (set_id) set_id = string_printing(set_id);
3802 /* For the non-OK cases, set up additional logging data if set_id
3806 set_id = set_id && *set_id
3807 ? string_sprintf(" (set_id=%s)", set_id) : US"";
3809 /* Switch on the result */
3814 if (!au->set_id || set_id) /* Complete success */
3816 if (set_id) authenticated_id = string_copy_perm(set_id, TRUE);
3817 sender_host_authenticated = au->name;
3818 sender_host_auth_pubname = au->public_name;
3819 authentication_failed = FALSE;
3820 authenticated_fail_id = NULL; /* Impossible to already be set? */
3823 (sender_host_address ? protocols : protocols_local)
3824 [pextend + pauthed + (tls_in.active.sock >= 0 ? pcrpted:0)];
3825 *s = *ss = US"235 Authentication succeeded";
3826 authenticated_by = au;
3830 /* Authentication succeeded, but we failed to expand the set_id string.
3831 Treat this as a temporary error. */
3833 auth_defer_msg = expand_string_message;
3837 if (set_id) authenticated_fail_id = string_copy_perm(set_id, TRUE);
3838 *s = string_sprintf("435 Unable to authenticate at present%s",
3839 auth_defer_user_msg);
3840 *ss = string_sprintf("435 Unable to authenticate at present%s: %s",
3841 set_id, auth_defer_msg);
3845 *s = *ss = US"501 Invalid base64 data";
3849 *s = *ss = US"501 Authentication cancelled";
3853 *s = *ss = US"553 Initial data not expected";
3857 if (set_id) authenticated_fail_id = string_copy_perm(set_id, TRUE);
3858 *s = US"535 Incorrect authentication data";
3859 *ss = string_sprintf("535 Incorrect authentication data%s", set_id);
3863 if (set_id) authenticated_fail_id = string_copy_perm(set_id, TRUE);
3864 *s = US"435 Internal error";
3865 *ss = string_sprintf("435 Internal error%s: return %d from authentication "
3866 "check", set_id, rc);
3878 qualify_recipient(uschar ** recipient, uschar * smtp_cmd_data, uschar * tag)
3881 if (f.allow_unqualified_recipient || strcmpic(*recipient, US"postmaster") == 0)
3883 DEBUG(D_receive) debug_printf("unqualified address %s accepted\n",
3885 rd = Ustrlen(recipient) + 1;
3886 /* deconst ok as *recipient was not const */
3887 *recipient = US rewrite_address_qualify(*recipient, TRUE);
3890 smtp_printf("501 %s: recipient address must contain a domain\r\n", FALSE,
3892 log_write(L_smtp_syntax_error,
3893 LOG_MAIN|LOG_REJECT, "unqualified %s rejected: <%s> %s%s",
3894 tag, *recipient, host_and_ident(TRUE), host_lookup_msg);
3902 smtp_quit_handler(uschar ** user_msgp, uschar ** log_msgp)
3905 f.smtp_in_quit = TRUE;
3906 incomplete_transaction_log(US"QUIT");
3908 && acl_check(ACL_WHERE_QUIT, NULL, acl_smtp_quit, user_msgp, log_msgp)
3910 log_write(0, LOG_MAIN|LOG_PANIC, "ACL for QUIT returned ERROR: %s",
3913 #ifdef EXIM_TCP_CORK
3914 (void) setsockopt(fileno(smtp_out), IPPROTO_TCP, EXIM_TCP_CORK, US &on, sizeof(on));
3918 smtp_respond(US"221", 3, TRUE, *user_msgp);
3920 smtp_printf("221 %s closing connection\r\n", FALSE, smtp_active_hostname);
3922 #ifdef SERVERSIDE_CLOSE_NOWAIT
3923 # ifndef DISABLE_TLS
3924 tls_close(NULL, TLS_SHUTDOWN_NOWAIT);
3927 log_write(L_smtp_connection, LOG_MAIN, "%s closed by QUIT",
3928 smtp_get_connection_info());
3931 # ifndef DISABLE_TLS
3932 tls_close(NULL, TLS_SHUTDOWN_WAIT);
3935 log_write(L_smtp_connection, LOG_MAIN, "%s closed by QUIT",
3936 smtp_get_connection_info());
3938 /* Pause, hoping client will FIN first so that they get the TIME_WAIT.
3939 The socket should become readble (though with no data) */
3941 (void) poll_one_fd(fileno(smtp_in), POLLIN, 200);
3942 #endif /*!SERVERSIDE_CLOSE_NOWAIT*/
3947 smtp_rset_handler(void)
3950 incomplete_transaction_log(US"RSET");
3951 smtp_printf("250 Reset OK\r\n", FALSE);
3952 cmd_list[CMD_LIST_RSET].is_mail_cmd = FALSE;
3957 expand_mailmax(const uschar * s)
3959 if (!(s = expand_cstring(s)))
3960 log_write(0, LOG_MAIN|LOG_PANIC, "failed to expand smtp_accept_max_per_connection");
3961 return *s ? Uatoi(s) : 0;
3964 /*************************************************
3965 * Initialize for SMTP incoming message *
3966 *************************************************/
3968 /* This function conducts the initial dialogue at the start of an incoming SMTP
3969 message, and builds a list of recipients. However, if the incoming message
3970 is part of a batch (-bS option) a separate function is called since it would
3971 be messy having tests splattered about all over this function. This function
3972 therefore handles the case where interaction is occurring. The input and output
3973 files are set up in smtp_in and smtp_out.
3975 The global recipients_list is set to point to a vector of recipient_item
3976 blocks, whose number is given by recipients_count. This is extended by the
3977 receive_add_recipient() function. The global variable sender_address is set to
3978 the sender's address. The yield is +1 if a message has been successfully
3979 started, 0 if a QUIT command was encountered or the connection was refused from
3980 the particular host, or -1 if the connection was lost.
3984 Returns: > 0 message successfully started (reached DATA)
3985 = 0 QUIT read or end of file reached or call refused
3990 smtp_setup_msg(void)
3993 BOOL toomany = FALSE;
3994 BOOL discarded = FALSE;
3995 BOOL last_was_rej_mail = FALSE;
3996 BOOL last_was_rcpt = FALSE;
3997 rmark reset_point = store_mark();
3999 DEBUG(D_receive) debug_printf("smtp_setup_msg entered\n");
4001 /* Reset for start of new message. We allow one RSET not to be counted as a
4002 nonmail command, for those MTAs that insist on sending it between every
4003 message. Ditto for EHLO/HELO and for STARTTLS, to allow for going in and out of
4004 TLS between messages (an Exim client may do this if it has messages queued up
4005 for the host). Note: we do NOT reset AUTH at this point. */
4007 reset_point = smtp_reset(reset_point);
4008 message_ended = END_NOTSTARTED;
4010 chunking_state = f.chunking_offered ? CHUNKING_OFFERED : CHUNKING_NOT_OFFERED;
4012 cmd_list[CMD_LIST_RSET].is_mail_cmd = TRUE;
4013 cmd_list[CMD_LIST_HELO].is_mail_cmd = TRUE;
4014 cmd_list[CMD_LIST_EHLO].is_mail_cmd = TRUE;
4016 cmd_list[CMD_LIST_STARTTLS].is_mail_cmd = TRUE;
4019 if (lwr_receive_getc != NULL)
4021 /* This should have already happened, but if we've gotten confused,
4022 force a reset here. */
4023 DEBUG(D_receive) debug_printf("WARNING: smtp_setup_msg had to restore receive functions to lowers\n");
4024 bdat_pop_receive_functions();
4027 /* Set the local signal handler for SIGTERM - it tries to end off tidily */
4029 had_command_sigterm = 0;
4030 os_non_restarting_signal(SIGTERM, command_sigterm_handler);
4032 /* Batched SMTP is handled in a different function. */
4034 if (smtp_batched_input) return smtp_setup_batch_msg();
4037 if (smtp_in) /* Avoid pure-ACKs while in cmd pingpong phase */
4038 (void) setsockopt(fileno(smtp_in), IPPROTO_TCP, TCP_QUICKACK,
4039 US &off, sizeof(off));
4042 /* Deal with SMTP commands. This loop is exited by setting done to a POSITIVE
4043 value. The values are 2 larger than the required yield of the function. */
4047 const uschar **argv;
4048 uschar *etrn_command;
4049 uschar *etrn_serialize_key;
4051 uschar *log_msg, *smtp_code;
4052 uschar *user_msg = NULL;
4053 uschar *recipient = NULL;
4054 uschar *hello = NULL;
4056 BOOL was_rej_mail = FALSE;
4057 BOOL was_rcpt = FALSE;
4058 void (*oldsignal)(int);
4060 int start, end, sender_domain, recipient_domain;
4063 uschar *orcpt = NULL;
4068 /* Check once per STARTTLS or SSL-on-connect for a TLS AUTH */
4069 if ( tls_in.active.sock >= 0
4071 && tls_in.certificate_verified
4072 && cmd_list[CMD_LIST_TLS_AUTH].is_mail_cmd
4075 cmd_list[CMD_LIST_TLS_AUTH].is_mail_cmd = FALSE;
4077 for (auth_instance * au = auths; au; au = au->next)
4078 if (strcmpic(US"tls", au->driver_name) == 0)
4081 && (rc = acl_check(ACL_WHERE_AUTH, NULL, acl_smtp_auth,
4082 &user_msg, &log_msg)) != OK
4084 done = smtp_handle_acl_fail(ACL_WHERE_AUTH, rc, user_msg, log_msg);
4087 smtp_cmd_data = NULL;
4089 if (smtp_in_auth(au, &s, &ss) == OK)
4090 { DEBUG(D_auth) debug_printf("tls auth succeeded\n"); }
4092 { DEBUG(D_auth) debug_printf("tls auth not succeeded\n"); }
4099 switch(smtp_read_command(
4100 #ifndef DISABLE_PIPE_CONNECT
4101 !fl.pipe_connect_acceptable,
4105 GETC_BUFFER_UNLIMITED))
4107 /* The AUTH command is not permitted to occur inside a transaction, and may
4108 occur successfully only once per connection. Actually, that isn't quite
4109 true. When TLS is started, all previous information about a connection must
4110 be discarded, so a new AUTH is permitted at that time.
4112 AUTH may only be used when it has been advertised. However, it seems that
4113 there are clients that send AUTH when it hasn't been advertised, some of
4114 them even doing this after HELO. And there are MTAs that accept this. Sigh.
4115 So there's a get-out that allows this to happen.
4117 AUTH is initially labelled as a "nonmail command" so that one occurrence
4118 doesn't get counted. We change the label here so that multiple failing
4119 AUTHS will eventually hit the nonmail threshold. */
4123 authentication_failed = TRUE;
4124 cmd_list[CMD_LIST_AUTH].is_mail_cmd = FALSE;
4126 if (!fl.auth_advertised && !f.allow_auth_unadvertised)
4128 done = synprot_error(L_smtp_protocol_error, 503, NULL,
4129 US"AUTH command used when not advertised");
4132 if (sender_host_authenticated)
4134 done = synprot_error(L_smtp_protocol_error, 503, NULL,
4135 US"already authenticated");
4140 done = synprot_error(L_smtp_protocol_error, 503, NULL,
4141 US"not permitted in mail transaction");
4148 && (rc = acl_check(ACL_WHERE_AUTH, NULL, acl_smtp_auth,
4149 &user_msg, &log_msg)) != OK
4152 done = smtp_handle_acl_fail(ACL_WHERE_AUTH, rc, user_msg, log_msg);
4156 /* Find the name of the requested authentication mechanism. */
4159 for (; (c = *smtp_cmd_data) && !isspace(c); smtp_cmd_data++)
4160 if (!isalnum(c) && c != '-' && c != '_')
4162 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4163 US"invalid character in authentication mechanism name");
4167 /* If not at the end of the line, we must be at white space. Terminate the
4168 name and move the pointer on to any data that may be present. */
4172 *smtp_cmd_data++ = 0;
4173 while (isspace(*smtp_cmd_data)) smtp_cmd_data++;
4176 /* Search for an authentication mechanism which is configured for use
4177 as a server and which has been advertised (unless, sigh, allow_auth_
4178 unadvertised is set). */
4182 for (au = auths; au; au = au->next)
4183 if (strcmpic(s, au->public_name) == 0 && au->server &&
4184 (au->advertised || f.allow_auth_unadvertised))
4189 c = smtp_in_auth(au, &s, &ss);
4191 smtp_printf("%s\r\n", FALSE, s);
4193 log_write(0, LOG_MAIN|LOG_REJECT, "%s authenticator failed for %s: %s",
4194 au->name, host_and_ident(FALSE), ss);
4197 done = synprot_error(L_smtp_protocol_error, 504, NULL,
4198 string_sprintf("%s authentication mechanism not supported", s));
4201 break; /* AUTH_CMD */
4203 /* The HELO/EHLO commands are permitted to appear in the middle of a
4204 session as well as at the beginning. They have the effect of a reset in
4205 addition to their other functions. Their absence at the start cannot be
4206 taken to be an error.
4210 If the EHLO command is not acceptable to the SMTP server, 501, 500,
4211 or 502 failure replies MUST be returned as appropriate. The SMTP
4212 server MUST stay in the same state after transmitting these replies
4213 that it was in before the EHLO was received.
4215 Therefore, we do not do the reset until after checking the command for
4216 acceptability. This change was made for Exim release 4.11. Previously
4217 it did the reset first. */
4230 HELO_EHLO: /* Common code for HELO and EHLO */
4231 cmd_list[CMD_LIST_HELO].is_mail_cmd = FALSE;
4232 cmd_list[CMD_LIST_EHLO].is_mail_cmd = FALSE;
4234 /* Reject the HELO if its argument was invalid or non-existent. A
4235 successful check causes the argument to be saved in malloc store. */
4237 if (!check_helo(smtp_cmd_data))
4239 smtp_printf("501 Syntactically invalid %s argument(s)\r\n", FALSE, hello);
4241 log_write(0, LOG_MAIN|LOG_REJECT, "rejected %s from %s: syntactically "
4242 "invalid argument(s): %s", hello, host_and_ident(FALSE),
4243 *smtp_cmd_argument == 0 ? US"(no argument given)" :
4244 string_printing(smtp_cmd_argument));
4246 if (++synprot_error_count > smtp_max_synprot_errors)
4248 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
4249 "syntax or protocol errors (last command was \"%s\", %s)",
4250 host_and_ident(FALSE), string_printing(smtp_cmd_buffer),
4251 string_from_gstring(s_connhad_log(NULL))
4259 /* If sender_host_unknown is true, we have got here via the -bs interface,
4260 not called from inetd. Otherwise, we are running an IP connection and the
4261 host address will be set. If the helo name is the primary name of this
4262 host and we haven't done a reverse lookup, force one now. If helo_verify_required
4263 is set, ensure that the HELO name matches the actual host. If helo_verify
4264 is set, do the same check, but softly. */
4266 if (!f.sender_host_unknown)
4268 BOOL old_helo_verified = f.helo_verified;
4269 uschar *p = smtp_cmd_data;
4271 while (*p != 0 && !isspace(*p)) { *p = tolower(*p); p++; }
4274 /* Force a reverse lookup if HELO quoted something in helo_lookup_domains
4275 because otherwise the log can be confusing. */
4277 if ( !sender_host_name
4278 && match_isinlist(sender_helo_name, CUSS &helo_lookup_domains, 0,
4279 &domainlist_anchor, NULL, MCL_DOMAIN, TRUE, NULL) == OK)
4280 (void)host_name_lookup();
4282 /* Rebuild the fullhost info to include the HELO name (and the real name
4283 if it was looked up.) */
4285 host_build_sender_fullhost(); /* Rebuild */
4286 set_process_info("handling%s incoming connection from %s",
4287 tls_in.active.sock >= 0 ? " TLS" : "", host_and_ident(FALSE));
4289 /* Verify if configured. This doesn't give much security, but it does
4290 make some people happy to be able to do it. If helo_verify_required is set,
4291 (host matches helo_verify_hosts) failure forces rejection. If helo_verify
4292 is set (host matches helo_try_verify_hosts), it does not. This is perhaps
4293 now obsolescent, since the verification can now be requested selectively
4296 f.helo_verified = f.helo_verify_failed = sender_helo_dnssec = FALSE;
4297 if (fl.helo_verify_required || fl.helo_verify)
4299 BOOL tempfail = !smtp_verify_helo();
4300 if (!f.helo_verified)
4302 if (fl.helo_verify_required)
4304 smtp_printf("%d %s argument does not match calling host\r\n", FALSE,
4305 tempfail? 451 : 550, hello);
4306 log_write(0, LOG_MAIN|LOG_REJECT, "%srejected \"%s %s\" from %s",
4307 tempfail? "temporarily " : "",
4308 hello, sender_helo_name, host_and_ident(FALSE));
4309 f.helo_verified = old_helo_verified;
4310 break; /* End of HELO/EHLO processing */
4312 HDEBUG(D_all) debug_printf("%s verification failed but host is in "
4313 "helo_try_verify_hosts\n", hello);
4319 /* set up SPF context */
4320 spf_conn_init(sender_helo_name, sender_host_address);
4323 /* Apply an ACL check if one is defined; afterwards, recheck
4324 synchronization in case the client started sending in a delay. */
4327 if ((rc = acl_check(ACL_WHERE_HELO, NULL, acl_smtp_helo,
4328 &user_msg, &log_msg)) != OK)
4330 done = smtp_handle_acl_fail(ACL_WHERE_HELO, rc, user_msg, log_msg);
4331 sender_helo_name = NULL;
4332 host_build_sender_fullhost(); /* Rebuild */
4335 #ifndef DISABLE_PIPE_CONNECT
4336 else if (!fl.pipe_connect_acceptable && !check_sync())
4338 else if (!check_sync())
4342 /* Generate an OK reply. The default string includes the ident if present,
4343 and also the IP address if present. Reflecting back the ident is intended
4344 as a deterrent to mail forgers. For maximum efficiency, and also because
4345 some broken systems expect each response to be in a single packet, arrange
4346 that the entire reply is sent in one write(). */
4348 fl.auth_advertised = FALSE;
4349 f.smtp_in_pipelining_advertised = FALSE;
4351 fl.tls_advertised = FALSE;
4353 fl.dsn_advertised = FALSE;
4355 fl.smtputf8_advertised = FALSE;
4358 /* Expand the per-connection message count limit option */
4359 smtp_mailcmd_max = expand_mailmax(smtp_accept_max_per_connection);
4361 smtp_code = US"250 "; /* Default response code plus space*/
4364 /* sender_host_name below will be tainted, so save on copy when we hit it */
4365 g = string_get_tainted(24, TRUE);
4366 g = string_fmt_append(g, "%.3s %s Hello %s%s%s",
4368 smtp_active_hostname,
4369 sender_ident ? sender_ident : US"",
4370 sender_ident ? US" at " : US"",
4371 sender_host_name ? sender_host_name : sender_helo_name);
4373 if (sender_host_address)
4374 g = string_fmt_append(g, " [%s]", sender_host_address);
4377 /* A user-supplied EHLO greeting may not contain more than one line. Note
4378 that the code returned by smtp_message_code() includes the terminating
4379 whitespace character. */
4385 smtp_message_code(&smtp_code, &codelen, &user_msg, NULL, TRUE);
4386 s = string_sprintf("%.*s%s", codelen, smtp_code, user_msg);
4387 if ((ss = strpbrk(CS s, "\r\n")) != NULL)
4389 log_write(0, LOG_MAIN|LOG_PANIC, "EHLO/HELO response must not contain "
4390 "newlines: message truncated: %s", string_printing(s));
4393 g = string_cat(NULL, s);
4396 g = string_catn(g, US"\r\n", 2);
4398 /* If we received EHLO, we must create a multiline response which includes
4399 the functions supported. */
4405 /* I'm not entirely happy with this, as an MTA is supposed to check
4406 that it has enough room to accept a message of maximum size before
4407 it sends this. However, there seems little point in not sending it.
4408 The actual size check happens later at MAIL FROM time. By postponing it
4409 till then, VRFY and EXPN can be used after EHLO when space is short. */
4411 if (thismessage_size_limit > 0)
4412 g = string_fmt_append(g, "%.3s-SIZE %d\r\n", smtp_code,
4413 thismessage_size_limit);
4416 g = string_catn(g, smtp_code, 3);
4417 g = string_catn(g, US"-SIZE\r\n", 7);
4420 #ifdef EXPERIMENTAL_ESMTP_LIMITS
4421 if ( (smtp_mailcmd_max > 0 || recipients_max)
4422 && verify_check_host(&limits_advertise_hosts) == OK)
4424 g = string_fmt_append(g, "%.3s-LIMITS", smtp_code);
4425 if (smtp_mailcmd_max > 0)
4426 g = string_fmt_append(g, " MAILMAX=%d", smtp_mailcmd_max);
4428 g = string_fmt_append(g, " RCPTMAX=%d", recipients_max);
4429 g = string_catn(g, US"\r\n", 2);
4433 /* Exim does not do protocol conversion or data conversion. It is 8-bit
4434 clean; if it has an 8-bit character in its hand, it just sends it. It
4435 cannot therefore specify 8BITMIME and remain consistent with the RFCs.
4436 However, some users want this option simply in order to stop MUAs
4437 mangling messages that contain top-bit-set characters. It is therefore
4438 provided as an option. */
4440 if (accept_8bitmime)
4442 g = string_catn(g, smtp_code, 3);
4443 g = string_catn(g, US"-8BITMIME\r\n", 11);
4446 /* Advertise DSN support if configured to do so. */
4447 if (verify_check_host(&dsn_advertise_hosts) != FAIL)
4449 g = string_catn(g, smtp_code, 3);
4450 g = string_catn(g, US"-DSN\r\n", 6);
4451 fl.dsn_advertised = TRUE;
4454 /* Advertise ETRN/VRFY/EXPN if there's are ACL checking whether a host is
4455 permitted to issue them; a check is made when any host actually tries. */
4459 g = string_catn(g, smtp_code, 3);
4460 g = string_catn(g, US"-ETRN\r\n", 7);
4464 g = string_catn(g, smtp_code, 3);
4465 g = string_catn(g, US"-VRFY\r\n", 7);
4469 g = string_catn(g, smtp_code, 3);
4470 g = string_catn(g, US"-EXPN\r\n", 7);
4473 /* Exim is quite happy with pipelining, so let the other end know that
4474 it is safe to use it, unless advertising is disabled. */
4476 if ( f.pipelining_enable
4477 && verify_check_host(&pipelining_advertise_hosts) == OK)
4479 g = string_catn(g, smtp_code, 3);
4480 g = string_catn(g, US"-PIPELINING\r\n", 13);
4481 sync_cmd_limit = NON_SYNC_CMD_PIPELINING;
4482 f.smtp_in_pipelining_advertised = TRUE;
4484 #ifndef DISABLE_PIPE_CONNECT
4485 if (fl.pipe_connect_acceptable)
4487 f.smtp_in_early_pipe_advertised = TRUE;
4488 g = string_catn(g, smtp_code, 3);
4489 g = string_catn(g, US"-" EARLY_PIPE_FEATURE_NAME "\r\n", EARLY_PIPE_FEATURE_LEN+3);
4495 /* If any server authentication mechanisms are configured, advertise
4496 them if the current host is in auth_advertise_hosts. The problem with
4497 advertising always is that some clients then require users to
4498 authenticate (and aren't configurable otherwise) even though it may not
4499 be necessary (e.g. if the host is in host_accept_relay).
4501 RFC 2222 states that SASL mechanism names contain only upper case
4502 letters, so output the names in upper case, though we actually recognize
4503 them in either case in the AUTH command. */
4507 && !sender_host_authenticated
4509 && verify_check_host(&auth_advertise_hosts) == OK
4513 for (auth_instance * au = auths; au; au = au->next)
4515 au->advertised = FALSE;
4518 DEBUG(D_auth+D_expand) debug_printf_indent(
4519 "Evaluating advertise_condition for %s %s athenticator\n",
4520 au->name, au->public_name);
4521 if ( !au->advertise_condition
4522 || expand_check_condition(au->advertise_condition, au->name,
4529 g = string_catn(g, smtp_code, 3);
4530 g = string_catn(g, US"-AUTH", 5);
4532 fl.auth_advertised = TRUE;
4535 g = string_catn(g, US" ", 1);
4536 g = string_cat (g, au->public_name);
4537 while (++saveptr < g->ptr) g->s[saveptr] = toupper(g->s[saveptr]);
4538 au->advertised = TRUE;
4543 if (!first) g = string_catn(g, US"\r\n", 2);
4546 /* RFC 3030 CHUNKING */
4548 if (verify_check_host(&chunking_advertise_hosts) != FAIL)
4550 g = string_catn(g, smtp_code, 3);
4551 g = string_catn(g, US"-CHUNKING\r\n", 11);
4552 f.chunking_offered = TRUE;
4553 chunking_state = CHUNKING_OFFERED;
4556 /* Advertise TLS (Transport Level Security) aka SSL (Secure Socket Layer)
4557 if it has been included in the binary, and the host matches
4558 tls_advertise_hosts. We must *not* advertise if we are already in a
4559 secure connection. */
4562 if (tls_in.active.sock < 0 &&
4563 verify_check_host(&tls_advertise_hosts) != FAIL)
4565 g = string_catn(g, smtp_code, 3);
4566 g = string_catn(g, US"-STARTTLS\r\n", 11);
4567 fl.tls_advertised = TRUE;
4571 #ifndef DISABLE_PRDR
4572 /* Per Recipient Data Response, draft by Eric A. Hall extending RFC */
4575 g = string_catn(g, smtp_code, 3);
4576 g = string_catn(g, US"-PRDR\r\n", 7);
4581 if ( accept_8bitmime
4582 && verify_check_host(&smtputf8_advertise_hosts) != FAIL)
4584 g = string_catn(g, smtp_code, 3);
4585 g = string_catn(g, US"-SMTPUTF8\r\n", 11);
4586 fl.smtputf8_advertised = TRUE;
4590 /* Finish off the multiline reply with one that is always available. */
4592 g = string_catn(g, smtp_code, 3);
4593 g = string_catn(g, US" HELP\r\n", 7);
4596 /* Terminate the string (for debug), write it, and note that HELO/EHLO
4600 if (tls_in.active.sock >= 0)
4601 (void)tls_write(NULL, g->s, g->ptr,
4602 # ifndef DISABLE_PIPE_CONNECT
4603 fl.pipe_connect_acceptable && pipeline_connect_sends());
4609 (void) fwrite(g->s, 1, g->ptr, smtp_out);
4615 (void) string_from_gstring(g);
4616 while ((cr = Ustrchr(g->s, '\r')) != NULL) /* lose CRs */
4617 memmove(cr, cr + 1, (g->ptr--) - (cr - g->s));
4618 debug_printf("SMTP>> %s", g->s);
4620 fl.helo_seen = TRUE;
4622 /* Reset the protocol and the state, abandoning any previous message. */
4624 (sender_host_address ? protocols : protocols_local)
4626 ? pextend + (sender_host_authenticated ? pauthed : 0)
4628 + (tls_in.active.sock >= 0 ? pcrpted : 0)
4630 cancel_cutthrough_connection(TRUE, US"sent EHLO response");
4631 reset_point = smtp_reset(reset_point);
4633 break; /* HELO/EHLO */
4636 /* The MAIL command requires an address as an operand. All we do
4637 here is to parse it for syntactic correctness. The form "<>" is
4638 a special case which converts into an empty string. The start/end
4639 pointers in the original are not used further for this address, as
4640 it is the canonical extracted address which is all that is kept. */
4644 smtp_mailcmd_count++; /* Count for limit and ratelimit */
4646 was_rej_mail = TRUE; /* Reset if accepted */
4647 env_mail_type_t * mail_args; /* Sanity check & validate args */
4650 if ( fl.helo_verify_required
4651 || verify_check_host(&hosts_require_helo) == OK)
4653 smtp_printf("503 HELO or EHLO required\r\n", FALSE);
4654 log_write(0, LOG_MAIN|LOG_REJECT, "rejected MAIL from %s: no "
4655 "HELO/EHLO given", host_and_ident(FALSE));
4658 else if (smtp_mailcmd_max < 0)
4659 smtp_mailcmd_max = expand_mailmax(smtp_accept_max_per_connection);
4663 done = synprot_error(L_smtp_protocol_error, 503, NULL,
4664 US"sender already given");
4668 if (!*smtp_cmd_data)
4670 done = synprot_error(L_smtp_protocol_error, 501, NULL,
4671 US"MAIL must have an address operand");
4675 /* Check to see if the limit for messages per connection would be
4676 exceeded by accepting further messages. */
4678 if (smtp_mailcmd_max > 0 && smtp_mailcmd_count > smtp_mailcmd_max)
4680 smtp_printf("421 too many messages in this connection\r\n", FALSE);
4681 log_write(0, LOG_MAIN|LOG_REJECT, "rejected MAIL command %s: too many "
4682 "messages in one connection", host_and_ident(TRUE));
4686 /* Reset for start of message - even if this is going to fail, we
4687 obviously need to throw away any previous data. */
4689 cancel_cutthrough_connection(TRUE, US"MAIL received");
4690 reset_point = smtp_reset(reset_point);
4692 sender_data = recipient_data = NULL;
4694 /* Loop, checking for ESMTP additions to the MAIL FROM command. */
4696 if (fl.esmtp) for(;;)
4698 uschar *name, *value, *end;
4699 unsigned long int size;
4700 BOOL arg_error = FALSE;
4702 if (!extract_option(&name, &value)) break;
4704 for (mail_args = env_mail_type_list;
4705 mail_args->value != ENV_MAIL_OPT_NULL;
4708 if (strcmpic(name, mail_args->name) == 0)
4710 if (mail_args->need_value && strcmpic(value, US"") == 0)
4713 switch(mail_args->value)
4715 /* Handle SIZE= by reading the value. We don't do the check till later,
4716 in order to be able to log the sender address on failure. */
4717 case ENV_MAIL_OPT_SIZE:
4718 if (((size = Ustrtoul(value, &end, 10)), *end == 0))
4720 if ((size == ULONG_MAX && errno == ERANGE) || size > INT_MAX)
4722 message_size = (int)size;
4728 /* If this session was initiated with EHLO and accept_8bitmime is set,
4729 Exim will have indicated that it supports the BODY=8BITMIME option. In
4730 fact, it does not support this according to the RFCs, in that it does not
4731 take any special action for forwarding messages containing 8-bit
4732 characters. That is why accept_8bitmime is not the default setting, but
4733 some sites want the action that is provided. We recognize both "8BITMIME"
4734 and "7BIT" as body types, but take no action. */
4735 case ENV_MAIL_OPT_BODY:
4736 if (accept_8bitmime) {
4737 if (strcmpic(value, US"8BITMIME") == 0)
4739 else if (strcmpic(value, US"7BIT") == 0)
4744 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4745 US"invalid data for BODY");
4748 DEBUG(D_receive) debug_printf("8BITMIME: %d\n", body_8bitmime);
4754 /* Handle the two DSN options, but only if configured to do so (which
4755 will have caused "DSN" to be given in the EHLO response). The code itself
4756 is included only if configured in at build time. */
4758 case ENV_MAIL_OPT_RET:
4759 if (fl.dsn_advertised)
4761 /* Check if RET has already been set */
4764 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4765 US"RET can be specified once only");
4768 dsn_ret = strcmpic(value, US"HDRS") == 0
4770 : strcmpic(value, US"FULL") == 0
4773 DEBUG(D_receive) debug_printf("DSN_RET: %d\n", dsn_ret);
4774 /* Check for invalid invalid value, and exit with error */
4777 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4778 US"Value for RET is invalid");
4783 case ENV_MAIL_OPT_ENVID:
4784 if (fl.dsn_advertised)
4786 /* Check if the dsn envid has been already set */
4789 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4790 US"ENVID can be specified once only");
4793 dsn_envid = string_copy(value);
4794 DEBUG(D_receive) debug_printf("DSN_ENVID: %s\n", dsn_envid);
4798 /* Handle the AUTH extension. If the value given is not "<>" and either
4799 the ACL says "yes" or there is no ACL but the sending host is
4800 authenticated, we set it up as the authenticated sender. However, if the
4801 authenticator set a condition to be tested, we ignore AUTH on MAIL unless
4802 the condition is met. The value of AUTH is an xtext, which means that +,
4803 = and cntrl chars are coded in hex; however "<>" is unaffected by this
4805 case ENV_MAIL_OPT_AUTH:
4806 if (Ustrcmp(value, "<>") != 0)
4811 if (auth_xtextdecode(value, &authenticated_sender) < 0)
4813 /* Put back terminator overrides for error message */
4816 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4817 US"invalid data for AUTH");
4820 if (!acl_smtp_mailauth)
4822 ignore_msg = US"client not authenticated";
4823 rc = sender_host_authenticated ? OK : FAIL;
4827 ignore_msg = US"rejected by ACL";
4828 rc = acl_check(ACL_WHERE_MAILAUTH, NULL, acl_smtp_mailauth,
4829 &user_msg, &log_msg);
4835 if (authenticated_by == NULL ||
4836 authenticated_by->mail_auth_condition == NULL ||
4837 expand_check_condition(authenticated_by->mail_auth_condition,
4838 authenticated_by->name, US"authenticator"))
4839 break; /* Accept the AUTH */
4841 ignore_msg = US"server_mail_auth_condition failed";
4842 if (authenticated_id != NULL)
4843 ignore_msg = string_sprintf("%s: authenticated ID=\"%s\"",
4844 ignore_msg, authenticated_id);
4849 authenticated_sender = NULL;
4850 log_write(0, LOG_MAIN, "ignoring AUTH=%s from %s (%s)",
4851 value, host_and_ident(TRUE), ignore_msg);
4854 /* Should only get DEFER or ERROR here. Put back terminator
4855 overrides for error message */
4860 (void)smtp_handle_acl_fail(ACL_WHERE_MAILAUTH, rc, user_msg,
4867 #ifndef DISABLE_PRDR
4868 case ENV_MAIL_OPT_PRDR:
4870 prdr_requested = TRUE;
4875 case ENV_MAIL_OPT_UTF8:
4876 if (!fl.smtputf8_advertised)
4878 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4879 US"SMTPUTF8 used when not advertised");
4883 DEBUG(D_receive) debug_printf("smtputf8 requested\n");
4884 message_smtputf8 = allow_utf8_domains = TRUE;
4885 if (Ustrncmp(received_protocol, US"utf8", 4) != 0)
4887 int old_pool = store_pool;
4888 store_pool = POOL_PERM;
4889 received_protocol = string_sprintf("utf8%s", received_protocol);
4890 store_pool = old_pool;
4895 /* No valid option. Stick back the terminator characters and break
4896 the loop. Do the name-terminator second as extract_option sets
4897 value==name when it found no equal-sign.
4898 An error for a malformed address will occur. */
4899 case ENV_MAIL_OPT_NULL:
4907 /* Break out of for loop if switch() had bad argument or
4908 when start of the email address is reached */
4909 if (arg_error) break;
4912 /* If we have passed the threshold for rate limiting, apply the current
4913 delay, and update it for next time, provided this is a limited host. */
4915 if (smtp_mailcmd_count > smtp_rlm_threshold &&
4916 verify_check_host(&smtp_ratelimit_hosts) == OK)
4918 DEBUG(D_receive) debug_printf("rate limit MAIL: delay %.3g sec\n",
4919 smtp_delay_mail/1000.0);
4920 millisleep((int)smtp_delay_mail);
4921 smtp_delay_mail *= smtp_rlm_factor;
4922 if (smtp_delay_mail > (double)smtp_rlm_limit)
4923 smtp_delay_mail = (double)smtp_rlm_limit;
4926 /* Now extract the address, first applying any SMTP-time rewriting. The
4927 TRUE flag allows "<>" as a sender address. */
4929 raw_sender = rewrite_existflags & rewrite_smtp
4930 /* deconst ok as smtp_cmd_data was not const */
4931 ? US rewrite_one(smtp_cmd_data, rewrite_smtp, NULL, FALSE, US"",
4932 global_rewrite_rules)
4936 parse_extract_address(raw_sender, &errmess, &start, &end, &sender_domain,
4941 done = synprot_error(L_smtp_syntax_error, 501, smtp_cmd_data, errmess);
4945 sender_address = raw_sender;
4947 /* If there is a configured size limit for mail, check that this message
4948 doesn't exceed it. The check is postponed to this point so that the sender
4951 if (thismessage_size_limit > 0 && message_size > thismessage_size_limit)
4953 smtp_printf("552 Message size exceeds maximum permitted\r\n", FALSE);
4954 log_write(L_size_reject,
4955 LOG_MAIN|LOG_REJECT, "rejected MAIL FROM:<%s> %s: "
4956 "message too big: size%s=%d max=%d",
4958 host_and_ident(TRUE),
4959 (message_size == INT_MAX)? ">" : "",
4961 thismessage_size_limit);
4962 sender_address = NULL;
4966 /* Check there is enough space on the disk unless configured not to.
4967 When smtp_check_spool_space is set, the check is for thismessage_size_limit
4968 plus the current message - i.e. we accept the message only if it won't
4969 reduce the space below the threshold. Add 5000 to the size to allow for
4970 overheads such as the Received: line and storing of recipients, etc.
4971 By putting the check here, even when SIZE is not given, it allow VRFY
4972 and EXPN etc. to be used when space is short. */
4974 if (!receive_check_fs(
4975 smtp_check_spool_space && message_size >= 0
4976 ? message_size + 5000 : 0))
4978 smtp_printf("452 Space shortage, please try later\r\n", FALSE);
4979 sender_address = NULL;
4983 /* If sender_address is unqualified, reject it, unless this is a locally
4984 generated message, or the sending host or net is permitted to send
4985 unqualified addresses - typically local machines behaving as MUAs -
4986 in which case just qualify the address. The flag is set above at the start
4987 of the SMTP connection. */
4989 if (!sender_domain && *sender_address)
4990 if (f.allow_unqualified_sender)
4992 sender_domain = Ustrlen(sender_address) + 1;
4993 /* deconst ok as sender_address was not const */
4994 sender_address = US rewrite_address_qualify(sender_address, FALSE);
4995 DEBUG(D_receive) debug_printf("unqualified address %s accepted\n",
5000 smtp_printf("501 %s: sender address must contain a domain\r\n", FALSE,
5002 log_write(L_smtp_syntax_error,
5003 LOG_MAIN|LOG_REJECT,
5004 "unqualified sender rejected: <%s> %s%s",
5006 host_and_ident(TRUE),
5008 sender_address = NULL;
5012 /* Apply an ACL check if one is defined, before responding. Afterwards,
5013 when pipelining is not advertised, do another sync check in case the ACL
5014 delayed and the client started sending in the meantime. */
5018 rc = acl_check(ACL_WHERE_MAIL, NULL, acl_smtp_mail, &user_msg, &log_msg);
5019 if (rc == OK && !f.smtp_in_pipelining_advertised && !check_sync())
5025 if (rc == OK || rc == DISCARD)
5027 BOOL more = pipeline_response();
5030 smtp_printf("%s%s%s", more, US"250 OK",
5031 #ifndef DISABLE_PRDR
5032 prdr_requested ? US", PRDR Requested" : US"",
5039 #ifndef DISABLE_PRDR
5041 user_msg = string_sprintf("%s%s", user_msg, US", PRDR Requested");
5043 smtp_user_msg(US"250", user_msg);
5045 smtp_delay_rcpt = smtp_rlr_base;
5046 f.recipients_discarded = (rc == DISCARD);
5047 was_rej_mail = FALSE;
5051 done = smtp_handle_acl_fail(ACL_WHERE_MAIL, rc, user_msg, log_msg);
5052 sender_address = NULL;
5057 /* The RCPT command requires an address as an operand. There may be any
5058 number of RCPT commands, specifying multiple recipients. We build them all
5059 into a data structure. The start/end values given by parse_extract_address
5060 are not used, as we keep only the extracted address. */
5064 /* We got really to many recipients. A check against configured
5065 limits is done later */
5066 if (rcpt_count < 0 || rcpt_count >= INT_MAX/2)
5067 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "Too many recipients: %d", rcpt_count);
5069 was_rcpt = fl.rcpt_in_progress = TRUE;
5071 /* There must be a sender address; if the sender was rejected and
5072 pipelining was advertised, we assume the client was pipelining, and do not
5073 count this as a protocol error. Reset was_rej_mail so that further RCPTs
5074 get the same treatment. */
5076 if (sender_address == NULL)
5078 if (f.smtp_in_pipelining_advertised && last_was_rej_mail)
5080 smtp_printf("503 sender not yet given\r\n", FALSE);
5081 was_rej_mail = TRUE;
5085 done = synprot_error(L_smtp_protocol_error, 503, NULL,
5086 US"sender not yet given");
5087 was_rcpt = FALSE; /* Not a valid RCPT */
5093 /* Check for an operand */
5095 if (smtp_cmd_data[0] == 0)
5097 done = synprot_error(L_smtp_syntax_error, 501, NULL,
5098 US"RCPT must have an address operand");
5103 /* Set the DSN flags orcpt and dsn_flags from the session*/
5107 if (fl.esmtp) for(;;)
5109 uschar *name, *value;
5111 if (!extract_option(&name, &value))
5114 if (fl.dsn_advertised && strcmpic(name, US"ORCPT") == 0)
5116 /* Check whether orcpt has been already set */
5119 done = synprot_error(L_smtp_syntax_error, 501, NULL,
5120 US"ORCPT can be specified once only");
5123 orcpt = string_copy(value);
5124 DEBUG(D_receive) debug_printf("DSN orcpt: %s\n", orcpt);
5127 else if (fl.dsn_advertised && strcmpic(name, US"NOTIFY") == 0)
5129 /* Check if the notify flags have been already set */
5132 done = synprot_error(L_smtp_syntax_error, 501, NULL,
5133 US"NOTIFY can be specified once only");
5136 if (strcmpic(value, US"NEVER") == 0)
5137 dsn_flags |= rf_notify_never;
5144 while (*pp != 0 && *pp != ',') pp++;
5145 if (*pp == ',') *pp++ = 0;
5146 if (strcmpic(p, US"SUCCESS") == 0)
5148 DEBUG(D_receive) debug_printf("DSN: Setting notify success\n");
5149 dsn_flags |= rf_notify_success;
5151 else if (strcmpic(p, US"FAILURE") == 0)
5153 DEBUG(D_receive) debug_printf("DSN: Setting notify failure\n");
5154 dsn_flags |= rf_notify_failure;
5156 else if (strcmpic(p, US"DELAY") == 0)
5158 DEBUG(D_receive) debug_printf("DSN: Setting notify delay\n");
5159 dsn_flags |= rf_notify_delay;
5163 /* Catch any strange values */
5164 done = synprot_error(L_smtp_syntax_error, 501, NULL,
5165 US"Invalid value for NOTIFY parameter");
5170 DEBUG(D_receive) debug_printf("DSN Flags: %x\n", dsn_flags);
5174 /* Unknown option. Stick back the terminator characters and break
5175 the loop. An error for a malformed address will occur. */
5179 DEBUG(D_receive) debug_printf("Invalid RCPT option: %s : %s\n", name, value);
5186 /* Apply SMTP rewriting then extract the working address. Don't allow "<>"
5187 as a recipient address */
5189 recipient = rewrite_existflags & rewrite_smtp
5190 /* deconst ok as smtp_cmd_data was not const */
5191 ? US rewrite_one(smtp_cmd_data, rewrite_smtp, NULL, FALSE, US"",
5192 global_rewrite_rules)
5195 if (!(recipient = parse_extract_address(recipient, &errmess, &start, &end,
5196 &recipient_domain, FALSE)))
5198 done = synprot_error(L_smtp_syntax_error, 501, smtp_cmd_data, errmess);
5203 /* If the recipient address is unqualified, reject it, unless this is a
5204 locally generated message. However, unqualified addresses are permitted
5205 from a configured list of hosts and nets - typically when behaving as
5206 MUAs rather than MTAs. Sad that SMTP is used for both types of traffic,
5207 really. The flag is set at the start of the SMTP connection.
5209 RFC 1123 talks about supporting "the reserved mailbox postmaster"; I always
5210 assumed this meant "reserved local part", but the revision of RFC 821 and
5211 friends now makes it absolutely clear that it means *mailbox*. Consequently
5212 we must always qualify this address, regardless. */
5214 if (!recipient_domain)
5215 if (!(recipient_domain = qualify_recipient(&recipient, smtp_cmd_data,
5222 /* Check maximum allowed */
5224 if (rcpt_count+1 < 0 || rcpt_count > recipients_max && recipients_max > 0)
5226 if (recipients_max_reject)
5229 smtp_printf("552 too many recipients\r\n", FALSE);
5231 log_write(0, LOG_MAIN|LOG_REJECT, "too many recipients: message "
5232 "rejected: sender=<%s> %s", sender_address, host_and_ident(TRUE));
5237 smtp_printf("452 too many recipients\r\n", FALSE);
5239 log_write(0, LOG_MAIN|LOG_REJECT, "too many recipients: excess "
5240 "temporarily rejected: sender=<%s> %s", sender_address,
5241 host_and_ident(TRUE));
5248 /* If we have passed the threshold for rate limiting, apply the current
5249 delay, and update it for next time, provided this is a limited host. */
5251 if (rcpt_count > smtp_rlr_threshold &&
5252 verify_check_host(&smtp_ratelimit_hosts) == OK)
5254 DEBUG(D_receive) debug_printf("rate limit RCPT: delay %.3g sec\n",
5255 smtp_delay_rcpt/1000.0);
5256 millisleep((int)smtp_delay_rcpt);
5257 smtp_delay_rcpt *= smtp_rlr_factor;
5258 if (smtp_delay_rcpt > (double)smtp_rlr_limit)
5259 smtp_delay_rcpt = (double)smtp_rlr_limit;
5262 /* If the MAIL ACL discarded all the recipients, we bypass ACL checking
5263 for them. Otherwise, check the access control list for this recipient. As
5264 there may be a delay in this, re-check for a synchronization error
5265 afterwards, unless pipelining was advertised. */
5267 if (f.recipients_discarded)
5270 if ( (rc = acl_check(ACL_WHERE_RCPT, recipient, acl_smtp_rcpt, &user_msg,
5272 && !f.smtp_in_pipelining_advertised && !check_sync())
5275 /* The ACL was happy */
5279 BOOL more = pipeline_response();
5282 smtp_user_msg(US"250", user_msg);
5284 smtp_printf("250 Accepted\r\n", more);
5285 receive_add_recipient(recipient, -1);
5287 /* Set the dsn flags in the recipients_list */
5288 recipients_list[recipients_count-1].orcpt = orcpt;
5289 recipients_list[recipients_count-1].dsn_flags = dsn_flags;
5291 /* DEBUG(D_receive) debug_printf("DSN: orcpt: %s flags: %d\n",
5292 recipients_list[recipients_count-1].orcpt,
5293 recipients_list[recipients_count-1].dsn_flags); */
5296 /* The recipient was discarded */
5298 else if (rc == DISCARD)
5301 smtp_user_msg(US"250", user_msg);
5303 smtp_printf("250 Accepted\r\n", FALSE);
5306 log_write(0, LOG_MAIN|LOG_REJECT, "%s F=<%s> RCPT %s: "
5307 "discarded by %s ACL%s%s", host_and_ident(TRUE),
5308 sender_address_unrewritten ? sender_address_unrewritten : sender_address,
5309 smtp_cmd_argument, f.recipients_discarded ? "MAIL" : "RCPT",
5310 log_msg ? US": " : US"", log_msg ? log_msg : US"");
5313 /* Either the ACL failed the address, or it was deferred. */
5317 if (rc == FAIL) rcpt_fail_count++; else rcpt_defer_count++;
5318 done = smtp_handle_acl_fail(ACL_WHERE_RCPT, rc, user_msg, log_msg);
5323 /* The DATA command is legal only if it follows successful MAIL FROM
5324 and RCPT TO commands. However, if pipelining is advertised, a bad DATA is
5325 not counted as a protocol error if it follows RCPT (which must have been
5326 rejected if there are no recipients.) This function is complete when a
5327 valid DATA command is encountered.
5329 Note concerning the code used: RFC 2821 says this:
5331 - If there was no MAIL, or no RCPT, command, or all such commands
5332 were rejected, the server MAY return a "command out of sequence"
5333 (503) or "no valid recipients" (554) reply in response to the
5336 The example in the pipelining RFC 2920 uses 554, but I use 503 here
5337 because it is the same whether pipelining is in use or not.
5339 If all the RCPT commands that precede DATA provoked the same error message
5340 (often indicating some kind of system error), it is helpful to include it
5341 with the DATA rejection (an idea suggested by Tony Finch). */
5348 if (chunking_state != CHUNKING_OFFERED)
5350 done = synprot_error(L_smtp_protocol_error, 503, NULL,
5351 US"BDAT command used when CHUNKING not advertised");
5355 /* grab size, endmarker */
5357 if (sscanf(CS smtp_cmd_data, "%u %n", &chunking_datasize, &n) < 1)
5359 done = synprot_error(L_smtp_protocol_error, 501, NULL,
5360 US"missing size for BDAT command");
5363 chunking_state = strcmpic(smtp_cmd_data+n, US"LAST") == 0
5364 ? CHUNKING_LAST : CHUNKING_ACTIVE;
5365 chunking_data_left = chunking_datasize;
5366 DEBUG(D_receive) debug_printf("chunking state %d, %d bytes\n",
5367 (int)chunking_state, chunking_data_left);
5369 f.bdat_readers_wanted = TRUE; /* FIXME: redundant vs chunking_state? */
5378 f.bdat_readers_wanted = FALSE;
5380 DATA_BDAT: /* Common code for DATA and BDAT */
5381 #ifndef DISABLE_PIPE_CONNECT
5382 fl.pipe_connect_acceptable = FALSE;
5384 if (!discarded && recipients_count <= 0)
5386 if (fl.rcpt_smtp_response_same && rcpt_smtp_response != NULL)
5388 uschar *code = US"503";
5389 int len = Ustrlen(rcpt_smtp_response);
5390 smtp_respond(code, 3, FALSE, US"All RCPT commands were rejected with "
5392 /* Responses from smtp_printf() will have \r\n on the end */
5393 if (len > 2 && rcpt_smtp_response[len-2] == '\r')
5394 rcpt_smtp_response[len-2] = 0;
5395 smtp_respond(code, 3, FALSE, rcpt_smtp_response);
5397 if (f.smtp_in_pipelining_advertised && last_was_rcpt)
5398 smtp_printf("503 Valid RCPT command must precede %s\r\n", FALSE,
5399 smtp_names[smtp_connection_had[SMTP_HBUFF_PREV(smtp_ch_index)]]);
5401 done = synprot_error(L_smtp_protocol_error, 503, NULL,
5402 smtp_connection_had[SMTP_HBUFF_PREV(smtp_ch_index)] == SCH_DATA
5403 ? US"valid RCPT command must precede DATA"
5404 : US"valid RCPT command must precede BDAT");
5406 if (chunking_state > CHUNKING_OFFERED)
5408 bdat_push_receive_functions();
5414 if (toomany && recipients_max_reject)
5416 sender_address = NULL; /* This will allow a new MAIL without RSET */
5417 sender_address_unrewritten = NULL;
5418 smtp_printf("554 Too many recipients\r\n", FALSE);
5420 if (chunking_state > CHUNKING_OFFERED)
5422 bdat_push_receive_functions();
5428 if (chunking_state > CHUNKING_OFFERED)
5429 rc = OK; /* No predata ACL or go-ahead output for BDAT */
5432 /* If there is an ACL, re-check the synchronization afterwards, since the
5433 ACL may have delayed. To handle cutthrough delivery enforce a dummy call
5434 to get the DATA command sent. */
5436 if (acl_smtp_predata == NULL && cutthrough.cctx.sock < 0)
5440 uschar * acl = acl_smtp_predata ? acl_smtp_predata : US"accept";
5441 f.enable_dollar_recipients = TRUE;
5442 rc = acl_check(ACL_WHERE_PREDATA, NULL, acl, &user_msg,
5444 f.enable_dollar_recipients = FALSE;
5445 if (rc == OK && !check_sync())
5449 { /* Either the ACL failed the address, or it was deferred. */
5450 done = smtp_handle_acl_fail(ACL_WHERE_PREDATA, rc, user_msg, log_msg);
5456 smtp_user_msg(US"354", user_msg);
5459 "354 Enter message, ending with \".\" on a line by itself\r\n", FALSE);
5462 if (f.bdat_readers_wanted)
5463 bdat_push_receive_functions();
5466 if (smtp_in) /* all ACKs needed to ramp window up for bulk data */
5467 (void) setsockopt(fileno(smtp_in), IPPROTO_TCP, TCP_QUICKACK,
5468 US &on, sizeof(on));
5471 message_ended = END_NOTENDED; /* Indicate in middle of data */
5482 if (!(address = parse_extract_address(smtp_cmd_data, &errmess,
5483 &start, &end, &recipient_domain, FALSE)))
5485 smtp_printf("501 %s\r\n", FALSE, errmess);
5489 if (!recipient_domain)
5490 if (!(recipient_domain = qualify_recipient(&address, smtp_cmd_data,
5494 if ((rc = acl_check(ACL_WHERE_VRFY, address, acl_smtp_vrfy,
5495 &user_msg, &log_msg)) != OK)
5496 done = smtp_handle_acl_fail(ACL_WHERE_VRFY, rc, user_msg, log_msg);
5500 address_item * addr = deliver_make_addr(address, FALSE);
5502 switch(verify_address(addr, NULL, vopt_is_recipient | vopt_qualify, -1,
5503 -1, -1, NULL, NULL, NULL))
5506 s = string_sprintf("250 <%s> is deliverable", address);
5510 s = (addr->user_message != NULL)?
5511 string_sprintf("451 <%s> %s", address, addr->user_message) :
5512 string_sprintf("451 Cannot resolve <%s> at this time", address);
5516 s = (addr->user_message != NULL)?
5517 string_sprintf("550 <%s> %s", address, addr->user_message) :
5518 string_sprintf("550 <%s> is not deliverable", address);
5519 log_write(0, LOG_MAIN, "VRFY failed for %s %s",
5520 smtp_cmd_argument, host_and_ident(TRUE));
5524 smtp_printf("%s\r\n", FALSE, s);
5532 rc = acl_check(ACL_WHERE_EXPN, NULL, acl_smtp_expn, &user_msg, &log_msg);
5534 done = smtp_handle_acl_fail(ACL_WHERE_EXPN, rc, user_msg, log_msg);
5537 BOOL save_log_testing_mode = f.log_testing_mode;
5538 f.address_test_mode = f.log_testing_mode = TRUE;
5539 (void) verify_address(deliver_make_addr(smtp_cmd_data, FALSE),
5540 smtp_out, vopt_is_recipient | vopt_qualify | vopt_expn, -1, -1, -1,
5542 f.address_test_mode = FALSE;
5543 f.log_testing_mode = save_log_testing_mode; /* true for -bh */
5552 if (!fl.tls_advertised)
5554 done = synprot_error(L_smtp_protocol_error, 503, NULL,
5555 US"STARTTLS command used when not advertised");
5559 /* Apply an ACL check if one is defined */
5561 if ( acl_smtp_starttls
5562 && (rc = acl_check(ACL_WHERE_STARTTLS, NULL, acl_smtp_starttls,
5563 &user_msg, &log_msg)) != OK
5566 done = smtp_handle_acl_fail(ACL_WHERE_STARTTLS, rc, user_msg, log_msg);
5570 /* RFC 2487 is not clear on when this command may be sent, though it
5571 does state that all information previously obtained from the client
5572 must be discarded if a TLS session is started. It seems reasonable to
5573 do an implied RSET when STARTTLS is received. */
5575 incomplete_transaction_log(US"STARTTLS");
5576 cancel_cutthrough_connection(TRUE, US"STARTTLS received");
5577 reset_point = smtp_reset(reset_point);
5579 cmd_list[CMD_LIST_STARTTLS].is_mail_cmd = FALSE;
5581 /* There's an attack where more data is read in past the STARTTLS command
5582 before TLS is negotiated, then assumed to be part of the secure session
5583 when used afterwards; we use segregated input buffers, so are not
5584 vulnerable, but we want to note when it happens and, for sheer paranoia,
5585 ensure that the buffer is "wiped".
5586 Pipelining sync checks will normally have protected us too, unless disabled
5587 by configuration. */
5589 if (receive_smtp_buffered())
5592 debug_printf("Non-empty input buffer after STARTTLS; naive attack?\n");
5593 if (tls_in.active.sock < 0)
5594 smtp_inend = smtp_inptr = smtp_inbuffer;
5595 /* and if TLS is already active, tls_server_start() should fail */
5598 /* There is nothing we value in the input buffer and if TLS is successfully
5599 negotiated, we won't use this buffer again; if TLS fails, we'll just read
5600 fresh content into it. The buffer contains arbitrary content from an
5601 untrusted remote source; eg: NOOP <shellcode>\r\nSTARTTLS\r\n
5602 It seems safest to just wipe away the content rather than leave it as a
5603 target to jump to. */
5605 memset(smtp_inbuffer, 0, IN_BUFFER_SIZE);
5607 /* Attempt to start up a TLS session, and if successful, discard all
5608 knowledge that was obtained previously. At least, that's what the RFC says,
5609 and that's what happens by default. However, in order to work round YAEB,
5610 there is an option to remember the esmtp state. Sigh.
5612 We must allow for an extra EHLO command and an extra AUTH command after
5613 STARTTLS that don't add to the nonmail command count. */
5616 if ((rc = tls_server_start(&s)) == OK)
5618 if (!tls_remember_esmtp)
5619 fl.helo_seen = fl.esmtp = fl.auth_advertised = f.smtp_in_pipelining_advertised = FALSE;
5620 cmd_list[CMD_LIST_EHLO].is_mail_cmd = TRUE;
5621 cmd_list[CMD_LIST_AUTH].is_mail_cmd = TRUE;
5622 cmd_list[CMD_LIST_TLS_AUTH].is_mail_cmd = TRUE;
5623 if (sender_helo_name)
5625 sender_helo_name = NULL;
5626 host_build_sender_fullhost(); /* Rebuild */
5627 set_process_info("handling incoming TLS connection from %s",
5628 host_and_ident(FALSE));
5631 (sender_host_address ? protocols : protocols_local)
5633 ? pextend + (sender_host_authenticated ? pauthed : 0)
5635 + (tls_in.active.sock >= 0 ? pcrpted : 0)
5638 sender_host_auth_pubname = sender_host_authenticated = NULL;
5639 authenticated_id = NULL;
5640 sync_cmd_limit = NON_SYNC_CMD_NON_PIPELINING;
5641 DEBUG(D_tls) debug_printf("TLS active\n");
5642 break; /* Successful STARTTLS */
5645 (void) smtp_log_tls_fail(s);
5647 /* Some local configuration problem was discovered before actually trying
5648 to do a TLS handshake; give a temporary error. */
5652 smtp_printf("454 TLS currently unavailable\r\n", FALSE);
5656 /* Hard failure. Reject everything except QUIT or closed connection. One
5657 cause for failure is a nested STARTTLS, in which case tls_in.active remains
5658 set, but we must still reject all incoming commands. Another is a handshake
5659 failure - and there may some encrypted data still in the pipe to us, which we
5660 see as garbage commands. */
5662 DEBUG(D_tls) debug_printf("TLS failed to start\n");
5663 while (done <= 0) switch(smtp_read_command(FALSE, GETC_BUFFER_UNLIMITED))
5666 log_write(L_smtp_connection, LOG_MAIN, "%s closed by EOF",
5667 smtp_get_connection_info());
5668 smtp_notquit_exit(US"tls-failed", NULL, NULL);
5672 /* It is perhaps arguable as to which exit ACL should be called here,
5673 but as it is probably a situation that almost never arises, it
5674 probably doesn't matter. We choose to call the real QUIT ACL, which in
5675 some sense is perhaps "right". */
5678 f.smtp_in_quit = TRUE;
5681 && ((rc = acl_check(ACL_WHERE_QUIT, NULL, acl_smtp_quit, &user_msg,
5682 &log_msg)) == ERROR))
5683 log_write(0, LOG_MAIN|LOG_PANIC, "ACL for QUIT returned ERROR: %s",
5686 smtp_respond(US"221", 3, TRUE, user_msg);
5688 smtp_printf("221 %s closing connection\r\n", FALSE, smtp_active_hostname);
5689 log_write(L_smtp_connection, LOG_MAIN, "%s closed by QUIT",
5690 smtp_get_connection_info());
5695 smtp_printf("554 Security failure\r\n", FALSE);
5698 tls_close(NULL, TLS_SHUTDOWN_NOWAIT);
5703 /* The ACL for QUIT is provided for gathering statistical information or
5704 similar; it does not affect the response code, but it can supply a custom
5708 smtp_quit_handler(&user_msg, &log_msg);
5714 smtp_rset_handler();
5715 cancel_cutthrough_connection(TRUE, US"RSET received");
5716 reset_point = smtp_reset(reset_point);
5723 smtp_printf("250 OK\r\n", FALSE);
5727 /* Show ETRN/EXPN/VRFY if there's an ACL for checking hosts; if actually
5728 used, a check will be done for permitted hosts. Show STARTTLS only if not
5729 already in a TLS session and if it would be advertised in the EHLO
5734 smtp_printf("214-Commands supported:\r\n", TRUE);
5738 Ustrcat(buffer, US" AUTH");
5740 if (tls_in.active.sock < 0 &&
5741 verify_check_host(&tls_advertise_hosts) != FAIL)
5742 Ustrcat(buffer, US" STARTTLS");
5744 Ustrcat(buffer, US" HELO EHLO MAIL RCPT DATA BDAT");
5745 Ustrcat(buffer, US" NOOP QUIT RSET HELP");
5746 if (acl_smtp_etrn) Ustrcat(buffer, US" ETRN");
5747 if (acl_smtp_expn) Ustrcat(buffer, US" EXPN");
5748 if (acl_smtp_vrfy) Ustrcat(buffer, US" VRFY");
5749 smtp_printf("214%s\r\n", FALSE, buffer);
5755 incomplete_transaction_log(US"connection lost");
5756 smtp_notquit_exit(US"connection-lost", US"421",
5757 US"%s lost input connection", smtp_active_hostname);
5759 /* Don't log by default unless in the middle of a message, as some mailers
5760 just drop the call rather than sending QUIT, and it clutters up the logs.
5763 if (sender_address || recipients_count > 0)
5764 log_write(L_lost_incoming_connection, LOG_MAIN,
5765 "unexpected %s while reading SMTP command from %s%s%s D=%s",
5766 f.sender_host_unknown ? "EOF" : "disconnection",
5767 f.tcp_in_fastopen_logged
5770 ? f.tcp_in_fastopen_data ? US"TFO* " : US"TFO "
5772 host_and_ident(FALSE), smtp_read_error,
5773 string_timesince(&smtp_connection_start)
5777 log_write(L_smtp_connection, LOG_MAIN, "%s %slost%s D=%s",
5778 smtp_get_connection_info(),
5779 f.tcp_in_fastopen && !f.tcp_in_fastopen_logged ? US"TFO " : US"",
5781 string_timesince(&smtp_connection_start)
5792 done = synprot_error(L_smtp_protocol_error, 503, NULL,
5793 US"ETRN is not permitted inside a transaction");
5797 log_write(L_etrn, LOG_MAIN, "ETRN %s received from %s", smtp_cmd_argument,
5798 host_and_ident(FALSE));
5800 if ((rc = acl_check(ACL_WHERE_ETRN, NULL, acl_smtp_etrn,
5801 &user_msg, &log_msg)) != OK)
5803 done = smtp_handle_acl_fail(ACL_WHERE_ETRN, rc, user_msg, log_msg);
5807 /* Compute the serialization key for this command. */
5809 etrn_serialize_key = string_sprintf("etrn-%s\n", smtp_cmd_data);
5811 /* If a command has been specified for running as a result of ETRN, we
5812 permit any argument to ETRN. If not, only the # standard form is permitted,
5813 since that is strictly the only kind of ETRN that can be implemented
5814 according to the RFC. */
5816 if (smtp_etrn_command)
5820 etrn_command = smtp_etrn_command;
5821 deliver_domain = smtp_cmd_data;
5822 rc = transport_set_up_command(&argv, smtp_etrn_command, TRUE, 0, NULL,
5823 US"ETRN processing", &error);
5824 deliver_domain = NULL;
5827 log_write(0, LOG_MAIN|LOG_PANIC, "failed to set up ETRN command: %s",
5829 smtp_printf("458 Internal failure\r\n", FALSE);
5834 /* Else set up to call Exim with the -R option. */
5838 if (*smtp_cmd_data++ != '#')
5840 done = synprot_error(L_smtp_syntax_error, 501, NULL,
5841 US"argument must begin with #");
5844 etrn_command = US"exim -R";
5845 argv = CUSS child_exec_exim(CEE_RETURN_ARGV, TRUE, NULL, TRUE,
5846 *queue_name ? 4 : 2,
5847 US"-R", smtp_cmd_data,
5848 US"-MCG", queue_name);
5851 /* If we are host-testing, don't actually do anything. */
5857 debug_printf("ETRN command is: %s\n", etrn_command);
5858 debug_printf("ETRN command execution skipped\n");
5860 if (user_msg == NULL) smtp_printf("250 OK\r\n", FALSE);
5861 else smtp_user_msg(US"250", user_msg);
5866 /* If ETRN queue runs are to be serialized, check the database to
5867 ensure one isn't already running. */
5869 if (smtp_etrn_serialize && !enq_start(etrn_serialize_key, 1))
5871 smtp_printf("458 Already processing %s\r\n", FALSE, smtp_cmd_data);
5875 /* Fork a child process and run the command. We don't want to have to
5876 wait for the process at any point, so set SIGCHLD to SIG_IGN before
5877 forking. It should be set that way anyway for external incoming SMTP,
5878 but we save and restore to be tidy. If serialization is required, we
5879 actually run the command in yet another process, so we can wait for it
5880 to complete and then remove the serialization lock. */
5882 oldsignal = signal(SIGCHLD, SIG_IGN);
5884 if ((pid = exim_fork(US"etrn-command")) == 0)
5886 smtp_input = FALSE; /* This process is not associated with the */
5887 (void)fclose(smtp_in); /* SMTP call any more. */
5888 (void)fclose(smtp_out);
5890 signal(SIGCHLD, SIG_DFL); /* Want to catch child */
5892 /* If not serializing, do the exec right away. Otherwise, fork down
5893 into another process. */
5895 if ( !smtp_etrn_serialize
5896 || (pid = exim_fork(US"etrn-serialised-command")) == 0)
5898 DEBUG(D_exec) debug_print_argv(argv);
5899 exim_nullstd(); /* Ensure std{in,out,err} exist */
5900 execv(CS argv[0], (char *const *)argv);
5901 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "exec of \"%s\" (ETRN) failed: %s",
5902 etrn_command, strerror(errno));
5903 _exit(EXIT_FAILURE); /* paranoia */
5906 /* Obey this if smtp_serialize and the 2nd fork yielded non-zero. That
5907 is, we are in the first subprocess, after forking again. All we can do
5908 for a failing fork is to log it. Otherwise, wait for the 2nd process to
5909 complete, before removing the serialization. */
5912 log_write(0, LOG_MAIN|LOG_PANIC, "2nd fork for serialized ETRN "
5913 "failed: %s", strerror(errno));
5917 DEBUG(D_any) debug_printf("waiting for serialized ETRN process %d\n",
5919 (void)wait(&status);
5920 DEBUG(D_any) debug_printf("serialized ETRN process %d ended\n",
5924 enq_end(etrn_serialize_key);
5925 exim_underbar_exit(EXIT_SUCCESS);
5928 /* Back in the top level SMTP process. Check that we started a subprocess
5929 and restore the signal state. */
5933 log_write(0, LOG_MAIN|LOG_PANIC, "fork of process for ETRN failed: %s",
5935 smtp_printf("458 Unable to fork process\r\n", FALSE);
5936 if (smtp_etrn_serialize) enq_end(etrn_serialize_key);
5940 smtp_printf("250 OK\r\n", FALSE);
5942 smtp_user_msg(US"250", user_msg);
5944 signal(SIGCHLD, oldsignal);
5949 done = synprot_error(L_smtp_syntax_error, 501, NULL,
5950 US"unexpected argument data");
5954 /* This currently happens only for NULLs, but could be extended. */
5957 done = synprot_error(L_smtp_syntax_error, 0, NULL, /* Just logs */
5958 US"NUL character(s) present (shown as '?')");
5959 smtp_printf("501 NUL characters are not allowed in SMTP commands\r\n",
5966 if (smtp_inend >= smtp_inbuffer + IN_BUFFER_SIZE)
5967 smtp_inend = smtp_inbuffer + IN_BUFFER_SIZE - 1;
5968 c = smtp_inend - smtp_inptr;
5969 if (c > 150) c = 150; /* limit logged amount */
5971 incomplete_transaction_log(US"sync failure");
5972 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP protocol synchronization error "
5973 "(next input sent too soon: pipelining was%s advertised): "
5974 "rejected \"%s\" %s next input=\"%s\"",
5975 f.smtp_in_pipelining_advertised ? "" : " not",
5976 smtp_cmd_buffer, host_and_ident(TRUE),
5977 string_printing(smtp_inptr));
5978 smtp_notquit_exit(US"synchronization-error", US"554",
5979 US"SMTP synchronization error");
5980 done = 1; /* Pretend eof - drops connection */
5984 case TOO_MANY_NONMAIL_CMD:
5985 s = smtp_cmd_buffer;
5986 while (*s != 0 && !isspace(*s)) s++;
5987 incomplete_transaction_log(US"too many non-mail commands");
5988 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
5989 "nonmail commands (last was \"%.*s\")", host_and_ident(FALSE),
5990 (int)(s - smtp_cmd_buffer), smtp_cmd_buffer);
5991 smtp_notquit_exit(US"bad-commands", US"554", US"Too many nonmail commands");
5992 done = 1; /* Pretend eof - drops connection */
5995 #ifdef SUPPORT_PROXY
5996 case PROXY_FAIL_IGNORE_CMD:
5997 smtp_printf("503 Command refused, required Proxy negotiation failed\r\n", FALSE);
6002 if (unknown_command_count++ >= smtp_max_unknown_commands)
6004 log_write(L_smtp_syntax_error, LOG_MAIN,
6005 "SMTP syntax error in \"%s\" %s %s",
6006 string_printing(smtp_cmd_buffer), host_and_ident(TRUE),
6007 US"unrecognized command");
6008 incomplete_transaction_log(US"unrecognized command");
6009 smtp_notquit_exit(US"bad-commands", US"500",
6010 US"Too many unrecognized commands");
6012 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
6013 "unrecognized commands (last was \"%s\")", host_and_ident(FALSE),
6014 string_printing(smtp_cmd_buffer));
6017 done = synprot_error(L_smtp_syntax_error, 500, NULL,
6018 US"unrecognized command");
6022 /* This label is used by goto's inside loops that want to break out to
6023 the end of the command-processing loop. */
6026 last_was_rej_mail = was_rej_mail; /* Remember some last commands for */
6027 last_was_rcpt = was_rcpt; /* protocol error handling */
6031 return done - 2; /* Convert yield values */
6037 authres_smtpauth(gstring * g)
6039 if (!sender_host_authenticated)
6042 g = string_append(g, 2, US";\n\tauth=pass (", sender_host_auth_pubname);
6044 if (Ustrcmp(sender_host_auth_pubname, "tls") == 0)
6045 g = authenticated_id
6046 ? string_append(g, 2, US") x509.auth=", authenticated_id)
6047 : string_cat(g, US") reason=x509.auth");
6049 g = authenticated_id
6050 ? string_append(g, 2, US") smtp.auth=", authenticated_id)
6051 : string_cat(g, US", no id saved)");
6053 if (authenticated_sender)
6054 g = string_append(g, 2, US" smtp.mailfrom=", authenticated_sender);
6062 /* End of smtp_in.c */