1 /*************************************************
2 * Exim - an Internet mail transport agent *
3 *************************************************/
5 /* Copyright (c) University of Cambridge 1995 - 2018 */
6 /* See the file NOTICE for conditions of use and distribution. */
8 /* Functions for handling an incoming SMTP call. */
15 /* Initialize for TCP wrappers if so configured. It appears that the macro
16 HAVE_IPV6 is used in some versions of the tcpd.h header, so we unset it before
17 including that header, and restore its value afterwards. */
19 #ifdef USE_TCP_WRAPPERS
22 #define EXIM_HAVE_IPV6
28 #define HAVE_IPV6 TRUE
31 int allow_severity = LOG_INFO;
32 int deny_severity = LOG_NOTICE;
33 uschar *tcp_wrappers_name;
37 /* Size of buffer for reading SMTP commands. We used to use 512, as defined
38 by RFC 821. However, RFC 1869 specifies that this must be increased for SMTP
39 commands that accept arguments, and this in particular applies to AUTH, where
40 the data can be quite long. More recently this value was 2048 in Exim;
41 however, RFC 4954 (circa 2007) recommends 12288 bytes to handle AUTH. Clients
42 such as Thunderbird will send an AUTH with an initial-response for GSSAPI.
43 The maximum size of a Kerberos ticket under Windows 2003 is 12000 bytes, and
44 we need room to handle large base64-encoded AUTHs for GSSAPI.
47 #define SMTP_CMD_BUFFER_SIZE 16384
49 /* Size of buffer for reading SMTP incoming packets */
51 #define IN_BUFFER_SIZE 8192
53 /* Structure for SMTP command list */
60 short int is_mail_cmd;
63 /* Codes for identifying commands. We order them so that those that come first
64 are those for which synchronization is always required. Checking this can help
68 /* These commands are required to be synchronized, i.e. to be the last in a
69 block of commands when pipelining. */
71 HELO_CMD, EHLO_CMD, DATA_CMD, /* These are listed in the pipelining */
72 VRFY_CMD, EXPN_CMD, NOOP_CMD, /* RFC as requiring synchronization */
73 ETRN_CMD, /* This by analogy with TURN from the RFC */
74 STARTTLS_CMD, /* Required by the STARTTLS RFC */
75 TLS_AUTH_CMD, /* auto-command at start of SSL */
77 /* This is a dummy to identify the non-sync commands when pipelining */
79 NON_SYNC_CMD_PIPELINING,
81 /* These commands need not be synchronized when pipelining */
83 MAIL_CMD, RCPT_CMD, RSET_CMD,
85 /* This is a dummy to identify the non-sync commands when not pipelining */
87 NON_SYNC_CMD_NON_PIPELINING,
89 /* RFC3030 section 2: "After all MAIL and RCPT responses are collected and
90 processed the message is sent using a series of BDAT commands"
91 implies that BDAT should be synchronized. However, we see Google, at least,
92 sending MAIL,RCPT,BDAT-LAST in a single packet, clearly not waiting for
93 processing of the RCPT response(s). We shall do the same, and not require
94 synch for BDAT. Worse, as the chunk may (very likely will) follow the
95 command-header in the same packet we cannot do the usual "is there any
96 follow-on data after the command line" even for non-pipeline mode.
97 So we'll need an explicit check after reading the expected chunk amount
98 when non-pipe, before sending the ACK. */
102 /* I have been unable to find a statement about the use of pipelining
103 with AUTH, so to be on the safe side it is here, though I kind of feel
104 it should be up there with the synchronized commands. */
108 /* I'm not sure about these, but I don't think they matter. */
113 PROXY_FAIL_IGNORE_CMD,
116 /* These are specials that don't correspond to actual commands */
118 EOF_CMD, OTHER_CMD, BADARG_CMD, BADCHAR_CMD, BADSYN_CMD,
119 TOO_MANY_NONMAIL_CMD };
122 /* This is a convenience macro for adding the identity of an SMTP command
123 to the circular buffer that holds a list of the last n received. */
126 smtp_connection_had[smtp_ch_index++] = n; \
127 if (smtp_ch_index >= SMTP_HBUFF_SIZE) smtp_ch_index = 0
130 /*************************************************
131 * Local static variables *
132 *************************************************/
135 BOOL auth_advertised :1;
137 BOOL tls_advertised :1;
139 BOOL dsn_advertised :1;
141 BOOL helo_required :1;
144 BOOL helo_accept_junk :1;
145 #ifndef DISABLE_PIPE_CONNECT
146 BOOL pipe_connect_acceptable :1;
148 BOOL rcpt_smtp_response_same :1;
149 BOOL rcpt_in_progress :1;
150 BOOL smtp_exit_function_called :1;
152 BOOL smtputf8_advertised :1;
155 .helo_required = FALSE,
156 .helo_verify = FALSE,
157 .smtp_exit_function_called = FALSE,
160 static auth_instance *authenticated_by;
161 static int count_nonmail;
162 static int nonmail_command_count;
163 static int synprot_error_count;
164 static int unknown_command_count;
165 static int sync_cmd_limit;
166 static int smtp_write_error = 0;
168 static uschar *rcpt_smtp_response;
169 static uschar *smtp_data_buffer;
170 static uschar *smtp_cmd_data;
172 /* We need to know the position of RSET, HELO, EHLO, AUTH, and STARTTLS. Their
173 final fields of all except AUTH are forced TRUE at the start of a new message
174 setup, to allow one of each between messages that is not counted as a nonmail
175 command. (In fact, only one of HELO/EHLO is not counted.) Also, we have to
176 allow a new EHLO after starting up TLS.
178 AUTH is "falsely" labelled as a mail command initially, so that it doesn't get
179 counted. However, the flag is changed when AUTH is received, so that multiple
180 failing AUTHs will eventually hit the limit. After a successful AUTH, another
181 AUTH is already forbidden. After a TLS session is started, AUTH's flag is again
182 forced TRUE, to allow for the re-authentication that can happen at that point.
184 QUIT is also "falsely" labelled as a mail command so that it doesn't up the
185 count of non-mail commands and possibly provoke an error.
187 tls_auth is a pseudo-command, never expected in input. It is activated
188 on TLS startup and looks for a tls authenticator. */
190 static smtp_cmd_list cmd_list[] = {
191 /* name len cmd has_arg is_mail_cmd */
193 { "rset", sizeof("rset")-1, RSET_CMD, FALSE, FALSE }, /* First */
194 { "helo", sizeof("helo")-1, HELO_CMD, TRUE, FALSE },
195 { "ehlo", sizeof("ehlo")-1, EHLO_CMD, TRUE, FALSE },
196 { "auth", sizeof("auth")-1, AUTH_CMD, TRUE, TRUE },
198 { "starttls", sizeof("starttls")-1, STARTTLS_CMD, FALSE, FALSE },
199 { "tls_auth", 0, TLS_AUTH_CMD, FALSE, FALSE },
202 /* If you change anything above here, also fix the definitions below. */
204 { "mail from:", sizeof("mail from:")-1, MAIL_CMD, TRUE, TRUE },
205 { "rcpt to:", sizeof("rcpt to:")-1, RCPT_CMD, TRUE, TRUE },
206 { "data", sizeof("data")-1, DATA_CMD, FALSE, TRUE },
207 { "bdat", sizeof("bdat")-1, BDAT_CMD, TRUE, TRUE },
208 { "quit", sizeof("quit")-1, QUIT_CMD, FALSE, TRUE },
209 { "noop", sizeof("noop")-1, NOOP_CMD, TRUE, FALSE },
210 { "etrn", sizeof("etrn")-1, ETRN_CMD, TRUE, FALSE },
211 { "vrfy", sizeof("vrfy")-1, VRFY_CMD, TRUE, FALSE },
212 { "expn", sizeof("expn")-1, EXPN_CMD, TRUE, FALSE },
213 { "help", sizeof("help")-1, HELP_CMD, TRUE, FALSE }
216 static smtp_cmd_list *cmd_list_end =
217 cmd_list + sizeof(cmd_list)/sizeof(smtp_cmd_list);
219 #define CMD_LIST_RSET 0
220 #define CMD_LIST_HELO 1
221 #define CMD_LIST_EHLO 2
222 #define CMD_LIST_AUTH 3
223 #define CMD_LIST_STARTTLS 4
224 #define CMD_LIST_TLS_AUTH 5
226 /* This list of names is used for performing the smtp_no_mail logging action.
227 It must be kept in step with the SCH_xxx enumerations. */
229 static uschar *smtp_names[] =
231 US"NONE", US"AUTH", US"DATA", US"BDAT", US"EHLO", US"ETRN", US"EXPN",
232 US"HELO", US"HELP", US"MAIL", US"NOOP", US"QUIT", US"RCPT", US"RSET",
233 US"STARTTLS", US"VRFY" };
235 static uschar *protocols_local[] = {
236 US"local-smtp", /* HELO */
237 US"local-smtps", /* The rare case EHLO->STARTTLS->HELO */
238 US"local-esmtp", /* EHLO */
239 US"local-esmtps", /* EHLO->STARTTLS->EHLO */
240 US"local-esmtpa", /* EHLO->AUTH */
241 US"local-esmtpsa" /* EHLO->STARTTLS->EHLO->AUTH */
243 static uschar *protocols[] = {
245 US"smtps", /* The rare case EHLO->STARTTLS->HELO */
246 US"esmtp", /* EHLO */
247 US"esmtps", /* EHLO->STARTTLS->EHLO */
248 US"esmtpa", /* EHLO->AUTH */
249 US"esmtpsa" /* EHLO->STARTTLS->EHLO->AUTH */
254 #define pcrpted 1 /* added to pextend or pnormal */
255 #define pauthed 2 /* added to pextend */
257 /* Sanity check and validate optional args to MAIL FROM: envelope */
260 ENV_MAIL_OPT_SIZE, ENV_MAIL_OPT_BODY, ENV_MAIL_OPT_AUTH,
264 ENV_MAIL_OPT_RET, ENV_MAIL_OPT_ENVID,
270 uschar * name; /* option requested during MAIL cmd */
271 int value; /* enum type */
272 BOOL need_value; /* TRUE requires value (name=value pair format)
273 FALSE is a singleton */
275 static env_mail_type_t env_mail_type_list[] = {
276 { US"SIZE", ENV_MAIL_OPT_SIZE, TRUE },
277 { US"BODY", ENV_MAIL_OPT_BODY, TRUE },
278 { US"AUTH", ENV_MAIL_OPT_AUTH, TRUE },
280 { US"PRDR", ENV_MAIL_OPT_PRDR, FALSE },
282 { US"RET", ENV_MAIL_OPT_RET, TRUE },
283 { US"ENVID", ENV_MAIL_OPT_ENVID, TRUE },
285 { US"SMTPUTF8",ENV_MAIL_OPT_UTF8, FALSE }, /* rfc6531 */
287 /* keep this the last entry */
288 { US"NULL", ENV_MAIL_OPT_NULL, FALSE },
291 /* When reading SMTP from a remote host, we have to use our own versions of the
292 C input-reading functions, in order to be able to flush the SMTP output only
293 when about to read more data from the socket. This is the only way to get
294 optimal performance when the client is using pipelining. Flushing for every
295 command causes a separate packet and reply packet each time; saving all the
296 responses up (when pipelining) combines them into one packet and one response.
298 For simplicity, these functions are used for *all* SMTP input, not only when
299 receiving over a socket. However, after setting up a secure socket (SSL), input
300 is read via the OpenSSL library, and another set of functions is used instead
303 These functions are set in the receive_getc etc. variables and called with the
304 same interface as the C functions. However, since there can only ever be
305 one incoming SMTP call, we just use a single buffer and flags. There is no need
306 to implement a complicated private FILE-like structure.*/
308 static uschar *smtp_inbuffer;
309 static uschar *smtp_inptr;
310 static uschar *smtp_inend;
311 static int smtp_had_eof;
312 static int smtp_had_error;
315 /* forward declarations */
316 static int smtp_read_command(BOOL check_sync, unsigned buffer_lim);
317 static int synprot_error(int type, int code, uschar *data, uschar *errmess);
318 static void smtp_quit_handler(uschar **, uschar **);
319 static void smtp_rset_handler(void);
321 /*************************************************
322 * Recheck synchronization *
323 *************************************************/
325 /* Synchronization checks can never be perfect because a packet may be on its
326 way but not arrived when the check is done. Normally, the checks happen when
327 commands are read: Exim ensures that there is no more input in the input buffer.
328 In normal cases, the response to the command will be fast, and there is no
331 However, for some commands an ACL is run, and that can include delays. In those
332 cases, it is useful to do another check on the input just before sending the
333 response. This also applies at the start of a connection. This function does
334 that check by means of the select() function, as long as the facility is not
335 disabled or inappropriate. A failure of select() is ignored.
337 When there is unwanted input, we read it so that it appears in the log of the
341 Returns: TRUE if all is well; FALSE if there is input pending
345 wouldblock_reading(void)
349 struct timeval tzero;
352 if (tls_in.active.sock >= 0)
353 return !tls_could_read();
356 if (smtp_inptr < smtp_inend)
359 fd = fileno(smtp_in);
364 rc = select(fd + 1, (SELECT_ARG2_TYPE *)&fds, NULL, NULL, &tzero);
366 if (rc <= 0) return TRUE; /* Not ready to read */
367 rc = smtp_getc(GETC_BUFFER_UNLIMITED);
368 if (rc < 0) return TRUE; /* End of file or error */
377 if (!smtp_enforce_sync || !sender_host_address || f.sender_host_notsocket)
380 return wouldblock_reading();
384 /* If there's input waiting (and we're doing pipelineing) then we can pipeline
385 a reponse with the one following. */
388 pipeline_response(void)
390 if ( !smtp_enforce_sync || !sender_host_address
391 || f.sender_host_notsocket || !f.smtp_in_pipelining_advertised)
394 if (wouldblock_reading()) return FALSE;
395 f.smtp_in_pipelining_used = TRUE;
400 #ifndef DISABLE_PIPE_CONNECT
402 pipeline_connect_sends(void)
404 if (!sender_host_address || f.sender_host_notsocket || !fl.pipe_connect_acceptable)
407 if (wouldblock_reading()) return FALSE;
408 f.smtp_in_early_pipe_used = TRUE;
413 /*************************************************
414 * Log incomplete transactions *
415 *************************************************/
417 /* This function is called after a transaction has been aborted by RSET, QUIT,
418 connection drops or other errors. It logs the envelope information received
419 so far in order to preserve address verification attempts.
421 Argument: string to indicate what aborted the transaction
426 incomplete_transaction_log(uschar *what)
428 if (!sender_address /* No transaction in progress */
429 || !LOGGING(smtp_incomplete_transaction))
432 /* Build list of recipients for logging */
434 if (recipients_count > 0)
436 raw_recipients = store_get(recipients_count * sizeof(uschar *), FALSE);
437 for (int i = 0; i < recipients_count; i++)
438 raw_recipients[i] = recipients_list[i].address;
439 raw_recipients_count = recipients_count;
442 log_write(L_smtp_incomplete_transaction, LOG_MAIN|LOG_SENDER|LOG_RECIPIENTS,
443 "%s incomplete transaction (%s)", host_and_ident(TRUE), what);
450 smtp_command_timeout_exit(void)
452 log_write(L_lost_incoming_connection,
453 LOG_MAIN, "SMTP command timeout on%s connection from %s",
454 tls_in.active.sock >= 0 ? " TLS" : "", host_and_ident(FALSE));
455 if (smtp_batched_input)
456 moan_smtp_batch(NULL, "421 SMTP command timeout"); /* Does not return */
457 smtp_notquit_exit(US"command-timeout", US"421",
458 US"%s: SMTP command timeout - closing connection",
459 smtp_active_hostname);
460 exim_exit(EXIT_FAILURE, US"receiving");
464 smtp_command_sigterm_exit(void)
466 log_write(0, LOG_MAIN, "%s closed after SIGTERM", smtp_get_connection_info());
467 if (smtp_batched_input)
468 moan_smtp_batch(NULL, "421 SIGTERM received"); /* Does not return */
469 smtp_notquit_exit(US"signal-exit", US"421",
470 US"%s: Service not available - closing connection", smtp_active_hostname);
471 exim_exit(EXIT_FAILURE, US"receiving");
475 smtp_data_timeout_exit(void)
477 log_write(L_lost_incoming_connection,
478 LOG_MAIN, "SMTP data timeout (message abandoned) on connection from %s F=<%s>",
479 sender_fullhost ? sender_fullhost : US"local process", sender_address);
480 receive_bomb_out(US"data-timeout", US"SMTP incoming data timeout");
481 /* Does not return */
485 smtp_data_sigint_exit(void)
487 log_write(0, LOG_MAIN, "%s closed after %s",
488 smtp_get_connection_info(), had_data_sigint == SIGTERM ? "SIGTERM":"SIGINT");
489 receive_bomb_out(US"signal-exit",
490 US"Service not available - SIGTERM or SIGINT received");
491 /* Does not return */
496 /* Refill the buffer, and notify DKIM verification code.
497 Return false for error or EOF.
501 smtp_refill(unsigned lim)
504 if (!smtp_out) return FALSE;
506 if (smtp_receive_timeout > 0) ALARM(smtp_receive_timeout);
508 /* Limit amount read, so non-message data is not fed to DKIM.
509 Take care to not touch the safety NUL at the end of the buffer. */
511 rc = read(fileno(smtp_in), smtp_inbuffer, MIN(IN_BUFFER_SIZE-1, lim));
513 if (smtp_receive_timeout > 0) ALARM_CLR(0);
516 /* Must put the error text in fixed store, because this might be during
517 header reading, where it releases unused store above the header. */
520 if (had_command_timeout) /* set by signal handler */
521 smtp_command_timeout_exit(); /* does not return */
522 if (had_command_sigterm)
523 smtp_command_sigterm_exit();
524 if (had_data_timeout)
525 smtp_data_timeout_exit();
527 smtp_data_sigint_exit();
529 smtp_had_error = save_errno;
530 smtp_read_error = string_copy_perm(
531 string_sprintf(" (error: %s)", strerror(save_errno)), FALSE);
538 dkim_exim_verify_feed(smtp_inbuffer, rc);
540 smtp_inend = smtp_inbuffer + rc;
541 smtp_inptr = smtp_inbuffer;
545 /*************************************************
546 * SMTP version of getc() *
547 *************************************************/
549 /* This gets the next byte from the SMTP input buffer. If the buffer is empty,
550 it flushes the output, and refills the buffer, with a timeout. The signal
551 handler is set appropriately by the calling function. This function is not used
552 after a connection has negotiated itself into an TLS/SSL state.
554 Arguments: lim Maximum amount to read/buffer
555 Returns: the next character or EOF
559 smtp_getc(unsigned lim)
561 if (smtp_inptr >= smtp_inend)
562 if (!smtp_refill(lim))
564 return *smtp_inptr++;
568 smtp_getbuf(unsigned * len)
573 if (smtp_inptr >= smtp_inend)
574 if (!smtp_refill(*len))
575 { *len = 0; return NULL; }
577 if ((size = smtp_inend - smtp_inptr) > *len) size = *len;
588 int n = smtp_inend - smtp_inptr;
590 dkim_exim_verify_feed(smtp_inptr, n);
595 /* Get a byte from the smtp input, in CHUNKING mode. Handle ack of the
596 previous BDAT chunk and getting new ones when we run out. Uses the
597 underlying smtp_getc or tls_getc both for that and for getting the
598 (buffered) data byte. EOD signals (an expected) no further data.
599 ERR signals a protocol error, and EOF a closed input stream.
601 Called from read_bdat_smtp() in receive.c for the message body, but also
602 by the headers read loop in receive_msg(); manipulates chunking_state
603 to handle the BDAT command/response.
604 Placed here due to the correlation with the above smtp_getc(), which it wraps,
605 and also by the need to do smtp command/response handling.
607 Arguments: lim (ignored)
608 Returns: the next character or ERR, EOD or EOF
612 bdat_getc(unsigned lim)
614 uschar * user_msg = NULL;
623 if (chunking_data_left > 0)
624 return lwr_receive_getc(chunking_data_left--);
626 receive_getc = lwr_receive_getc;
627 receive_getbuf = lwr_receive_getbuf;
628 receive_ungetc = lwr_receive_ungetc;
630 dkim_save = dkim_collect_input;
631 dkim_collect_input = 0;
634 /* Unless PIPELINING was offered, there should be no next command
635 until after we ack that chunk */
637 if (!f.smtp_in_pipelining_advertised && !check_sync())
639 unsigned n = smtp_inend - smtp_inptr;
642 incomplete_transaction_log(US"sync failure");
643 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP protocol synchronization error "
644 "(next input sent too soon: pipelining was not advertised): "
645 "rejected \"%s\" %s next input=\"%s\"%s",
646 smtp_cmd_buffer, host_and_ident(TRUE),
647 string_printing(string_copyn(smtp_inptr, n)),
648 smtp_inend - smtp_inptr > n ? "..." : "");
649 (void) synprot_error(L_smtp_protocol_error, 554, NULL,
650 US"SMTP synchronization error");
651 goto repeat_until_rset;
654 /* If not the last, ack the received chunk. The last response is delayed
655 until after the data ACL decides on it */
657 if (chunking_state == CHUNKING_LAST)
660 dkim_exim_verify_feed(NULL, 0); /* notify EOD */
665 smtp_printf("250 %u byte chunk received\r\n", FALSE, chunking_datasize);
666 chunking_state = CHUNKING_OFFERED;
667 DEBUG(D_receive) debug_printf("chunking state %d\n", (int)chunking_state);
669 /* Expect another BDAT cmd from input. RFC 3030 says nothing about
670 QUIT, RSET or NOOP but handling them seems obvious */
673 switch(smtp_read_command(TRUE, 1))
676 (void) synprot_error(L_smtp_protocol_error, 503, NULL,
677 US"only BDAT permissible after non-LAST BDAT");
680 switch(smtp_read_command(TRUE, 1))
682 case QUIT_CMD: smtp_quit_handler(&user_msg, &log_msg); /*FALLTHROUGH */
683 case EOF_CMD: return EOF;
684 case RSET_CMD: smtp_rset_handler(); return ERR;
685 default: if (synprot_error(L_smtp_protocol_error, 503, NULL,
686 US"only RSET accepted now") > 0)
688 goto repeat_until_rset;
692 smtp_quit_handler(&user_msg, &log_msg);
703 smtp_printf("250 OK\r\n", FALSE);
710 if (sscanf(CS smtp_cmd_data, "%u %n", &chunking_datasize, &n) < 1)
712 (void) synprot_error(L_smtp_protocol_error, 501, NULL,
713 US"missing size for BDAT command");
716 chunking_state = strcmpic(smtp_cmd_data+n, US"LAST") == 0
717 ? CHUNKING_LAST : CHUNKING_ACTIVE;
718 chunking_data_left = chunking_datasize;
719 DEBUG(D_receive) debug_printf("chunking state %d, %d bytes\n",
720 (int)chunking_state, chunking_data_left);
722 if (chunking_datasize == 0)
723 if (chunking_state == CHUNKING_LAST)
727 (void) synprot_error(L_smtp_protocol_error, 504, NULL,
728 US"zero size for BDAT command");
729 goto repeat_until_rset;
732 receive_getc = bdat_getc;
733 receive_getbuf = bdat_getbuf; /* r~getbuf is never actually used */
734 receive_ungetc = bdat_ungetc;
736 dkim_collect_input = dkim_save;
738 break; /* to top of main loop */
745 bdat_getbuf(unsigned * len)
749 if (chunking_data_left <= 0)
750 { *len = 0; return NULL; }
752 if (*len > chunking_data_left) *len = chunking_data_left;
753 buf = lwr_receive_getbuf(len); /* Either smtp_getbuf or tls_getbuf */
754 chunking_data_left -= *len;
759 bdat_flush_data(void)
761 while (chunking_data_left)
763 unsigned n = chunking_data_left;
764 if (!bdat_getbuf(&n)) break;
767 receive_getc = lwr_receive_getc;
768 receive_getbuf = lwr_receive_getbuf;
769 receive_ungetc = lwr_receive_ungetc;
771 if (chunking_state != CHUNKING_LAST)
773 chunking_state = CHUNKING_OFFERED;
774 DEBUG(D_receive) debug_printf("chunking state %d\n", (int)chunking_state);
781 /*************************************************
782 * SMTP version of ungetc() *
783 *************************************************/
785 /* Puts a character back in the input buffer. Only ever
791 Returns: the character
805 chunking_data_left++;
806 return lwr_receive_ungetc(ch);
811 /*************************************************
812 * SMTP version of feof() *
813 *************************************************/
815 /* Tests for a previous EOF
818 Returns: non-zero if the eof flag is set
830 /*************************************************
831 * SMTP version of ferror() *
832 *************************************************/
834 /* Tests for a previous read error, and returns with errno
835 restored to what it was when the error was detected.
838 Returns: non-zero if the error flag is set
844 errno = smtp_had_error;
845 return smtp_had_error;
850 /*************************************************
851 * Test for characters in the SMTP buffer *
852 *************************************************/
854 /* Used at the end of a message
863 return smtp_inptr < smtp_inend;
868 /*************************************************
869 * Write formatted string to SMTP channel *
870 *************************************************/
872 /* This is a separate function so that we don't have to repeat everything for
873 TLS support or debugging. It is global so that the daemon and the
874 authentication functions can use it. It does not return any error indication,
875 because major problems such as dropped connections won't show up till an output
876 flush for non-TLS connections. The smtp_fflush() function is available for
877 checking that: for convenience, TLS output errors are remembered here so that
878 they are also picked up later by smtp_fflush().
880 This function is exposed to the local_scan API; do not change the signature.
884 more further data expected
885 ... optional arguments
891 smtp_printf(const char *format, BOOL more, ...)
896 smtp_vprintf(format, more, ap);
900 /* This is split off so that verify.c:respond_printf() can, in effect, call
901 smtp_printf(), bearing in mind that in C a vararg function can't directly
902 call another vararg function, only a function which accepts a va_list.
904 This function is exposed to the local_scan API; do not change the signature.
906 /*XXX consider passing caller-info in, for string_vformat-onward */
909 smtp_vprintf(const char *format, BOOL more, va_list ap)
911 gstring gs = { .size = big_buffer_size, .ptr = 0, .s = big_buffer };
914 /* Use taint-unchecked routines for writing into big_buffer, trusting
915 that we'll never expand it. */
917 yield = !! string_vformat(&gs, SVFMT_TAINT_NOCHK, format, ap);
918 string_from_gstring(&gs);
922 uschar *msg_copy, *cr, *end;
923 msg_copy = string_copy(gs.s);
924 end = msg_copy + gs.ptr;
925 while ((cr = Ustrchr(msg_copy, '\r')) != NULL) /* lose CRs */
926 memmove(cr, cr + 1, (end--) - cr);
927 debug_printf("SMTP>> %s", msg_copy);
932 log_write(0, LOG_MAIN|LOG_PANIC, "string too large in smtp_printf()");
933 smtp_closedown(US"Unexpected error");
934 exim_exit(EXIT_FAILURE, NULL);
937 /* If this is the first output for a (non-batch) RCPT command, see if all RCPTs
938 have had the same. Note: this code is also present in smtp_respond(). It would
939 be tidier to have it only in one place, but when it was added, it was easier to
940 do it that way, so as not to have to mess with the code for the RCPT command,
941 which sometimes uses smtp_printf() and sometimes smtp_respond(). */
943 if (fl.rcpt_in_progress)
945 if (rcpt_smtp_response == NULL)
946 rcpt_smtp_response = string_copy(big_buffer);
947 else if (fl.rcpt_smtp_response_same &&
948 Ustrcmp(rcpt_smtp_response, big_buffer) != 0)
949 fl.rcpt_smtp_response_same = FALSE;
950 fl.rcpt_in_progress = FALSE;
953 /* Now write the string */
957 tls_in.active.sock >= 0 ? (tls_write(NULL, gs.s, gs.ptr, more) < 0) :
959 (fwrite(gs.s, gs.ptr, 1, smtp_out) == 0)
961 smtp_write_error = -1;
966 /*************************************************
967 * Flush SMTP out and check for error *
968 *************************************************/
970 /* This function isn't currently used within Exim (it detects errors when it
971 tries to read the next SMTP input), but is available for use in local_scan().
972 It flushes the output and checks for errors.
975 Returns: 0 for no error; -1 after an error
981 if (tls_in.active.sock < 0 && fflush(smtp_out) != 0) smtp_write_error = -1;
985 tls_in.active.sock >= 0 ? (tls_write(NULL, NULL, 0, FALSE) < 0) :
987 (fflush(smtp_out) != 0)
989 smtp_write_error = -1;
991 return smtp_write_error;
996 /*************************************************
997 * SMTP command read timeout *
998 *************************************************/
1000 /* Signal handler for timing out incoming SMTP commands. This attempts to
1003 Argument: signal number (SIGALRM)
1008 command_timeout_handler(int sig)
1010 had_command_timeout = sig;
1015 /*************************************************
1016 * SIGTERM received *
1017 *************************************************/
1019 /* Signal handler for handling SIGTERM. Again, try to finish tidily.
1021 Argument: signal number (SIGTERM)
1026 command_sigterm_handler(int sig)
1028 had_command_sigterm = sig;
1034 #ifdef SUPPORT_PROXY
1035 /*************************************************
1036 * Restore socket timeout to previous value *
1037 *************************************************/
1038 /* If the previous value was successfully retrieved, restore
1039 it before returning control to the non-proxy routines
1041 Arguments: fd - File descriptor for input
1042 get_ok - Successfully retrieved previous values
1043 tvtmp - Time struct with previous values
1044 vslen - Length of time struct
1048 restore_socket_timeout(int fd, int get_ok, struct timeval * tvtmp, socklen_t vslen)
1051 (void) setsockopt(fd, SOL_SOCKET, SO_RCVTIMEO, CS tvtmp, vslen);
1054 /*************************************************
1055 * Check if host is required proxy host *
1056 *************************************************/
1057 /* The function determines if inbound host will be a regular smtp host
1058 or if it is configured that it must use Proxy Protocol. A local
1066 check_proxy_protocol_host()
1070 if ( sender_host_address
1071 && (rc = verify_check_this_host(CUSS &hosts_proxy, NULL, NULL,
1072 sender_host_address, NULL)) == OK)
1075 debug_printf("Detected proxy protocol configured host\n");
1076 proxy_session = TRUE;
1078 return proxy_session;
1082 /*************************************************
1083 * Read data until newline or end of buffer *
1084 *************************************************/
1085 /* While SMTP is server-speaks-first, TLS is client-speaks-first, so we can't
1086 read an entire buffer and assume there will be nothing past a proxy protocol
1087 header. Our approach normally is to use stdio, but again that relies upon
1088 "STARTTLS\r\n" and a server response before the client starts TLS handshake, or
1089 reading _nothing_ before client TLS handshake. So we don't want to use the
1090 usual buffering reads which may read enough to block TLS starting.
1092 So unfortunately we're down to "read one byte at a time, with a syscall each,
1093 and expect a little overhead", for all proxy-opened connections which are v1,
1094 just to handle the TLS-on-connect case. Since SSL functions wrap the
1095 underlying fd, we can't assume that we can feed them any already-read content.
1097 We need to know where to read to, the max capacity, and we'll read until we
1098 get a CR and one more character. Let the caller scream if it's CR+!LF.
1100 Return the amount read.
1104 swallow_until_crlf(int fd, uschar *base, int already, int capacity)
1106 uschar *to = base + already;
1112 /* For "PROXY UNKNOWN\r\n" we, at time of writing, expect to have read
1113 up through the \r; for the _normal_ case, we haven't yet seen the \r. */
1115 cr = memchr(base, '\r', already);
1118 if ((cr - base) < already - 1)
1120 /* \r and presumed \n already within what we have; probably not
1121 actually proxy protocol, but abort cleanly. */
1124 /* \r is last character read, just need one more. */
1128 while (capacity > 0)
1130 do { ret = recv(fd, to, 1, 0); } while (ret == -1 && errno == EINTR);
1142 /* reached end without having room for a final newline, abort */
1147 /*************************************************
1148 * Setup host for proxy protocol *
1149 *************************************************/
1150 /* The function configures the connection based on a header from the
1151 inbound host to use Proxy Protocol. The specification is very exact
1152 so exit with an error if do not find the exact required pieces. This
1153 includes an incorrect number of spaces separating args.
1156 Returns: Boolean success
1160 setup_proxy_protocol_host()
1172 struct { /* TCP/UDP over IPv4, len = 12 */
1178 struct { /* TCP/UDP over IPv6, len = 36 */
1179 uint8_t src_addr[16];
1180 uint8_t dst_addr[16];
1184 struct { /* AF_UNIX sockets, len = 216 */
1185 uschar src_addr[108];
1186 uschar dst_addr[108];
1192 /* Temp variables used in PPv2 address:port parsing */
1194 char tmpip[INET_ADDRSTRLEN];
1195 struct sockaddr_in tmpaddr;
1196 char tmpip6[INET6_ADDRSTRLEN];
1197 struct sockaddr_in6 tmpaddr6;
1199 /* We can't read "all data until end" because while SMTP is
1200 server-speaks-first, the TLS handshake is client-speaks-first, so for
1201 TLS-on-connect ports the proxy protocol header will usually be immediately
1202 followed by a TLS handshake, and with N TLS libraries, we can't reliably
1203 reinject data for reading by those. So instead we first read "enough to be
1204 safely read within the header, and figure out how much more to read".
1205 For v1 we will later read to the end-of-line, for v2 we will read based upon
1208 The v2 sig is 12 octets, and another 4 gets us the length, so we know how much
1209 data is needed total. For v1, where the line looks like:
1210 PROXY TCPn L3src L3dest SrcPort DestPort \r\n
1212 However, for v1 there's also `PROXY UNKNOWN\r\n` which is only 15 octets.
1213 We seem to support that. So, if we read 14 octets then we can tell if we're
1214 v2 or v1. If we're v1, we can continue reading as normal.
1216 If we're v2, we can't slurp up the entire header. We need the length in the
1217 15th & 16th octets, then to read everything after that.
1219 So to safely handle v1 and v2, with client-sent-first supported correctly,
1220 we have to do a minimum of 3 read calls, not 1. Eww.
1223 #define PROXY_INITIAL_READ 14
1224 #define PROXY_V2_HEADER_SIZE 16
1225 #if PROXY_INITIAL_READ > PROXY_V2_HEADER_SIZE
1226 # error Code bug in sizes of data to read for proxy usage
1231 int fd = fileno(smtp_in);
1232 const char v2sig[12] = "\x0D\x0A\x0D\x0A\x00\x0D\x0A\x51\x55\x49\x54\x0A";
1233 uschar * iptype; /* To display debug info */
1235 struct timeval tvtmp;
1236 socklen_t vslen = sizeof(struct timeval);
1239 /* Save current socket timeout values */
1240 get_ok = getsockopt(fd, SOL_SOCKET, SO_RCVTIMEO, CS &tvtmp, &vslen);
1242 /* Proxy Protocol host must send header within a short time
1243 (default 3 seconds) or it's considered invalid */
1244 tv.tv_sec = PROXY_NEGOTIATION_TIMEOUT_SEC;
1245 tv.tv_usec = PROXY_NEGOTIATION_TIMEOUT_USEC;
1246 if (setsockopt(fd, SOL_SOCKET, SO_RCVTIMEO, CS &tv, sizeof(tv)) < 0)
1251 /* The inbound host was declared to be a Proxy Protocol host, so
1252 don't do a PEEK into the data, actually slurp up enough to be
1253 "safe". Can't take it all because TLS-on-connect clients follow
1254 immediately with TLS handshake. */
1255 ret = recv(fd, &hdr, PROXY_INITIAL_READ, 0);
1257 while (ret == -1 && errno == EINTR);
1262 /* For v2, handle reading the length, and then the rest. */
1263 if ((ret == PROXY_INITIAL_READ) && (memcmp(&hdr.v2, v2sig, sizeof(v2sig)) == 0))
1268 /* First get the length fields. */
1271 retmore = recv(fd, (uschar*)&hdr + ret, PROXY_V2_HEADER_SIZE - PROXY_INITIAL_READ, 0);
1272 } while (retmore == -1 && errno == EINTR);
1277 ver = (hdr.v2.ver_cmd & 0xf0) >> 4;
1279 /* May 2014: haproxy combined the version and command into one byte to
1280 allow two full bytes for the length field in order to proxy SSL
1281 connections. SSL Proxy is not supported in this version of Exim, but
1282 must still separate values here. */
1286 DEBUG(D_receive) debug_printf("Invalid Proxy Protocol version: %d\n", ver);
1290 /* The v2 header will always be 16 bytes per the spec. */
1291 size = 16 + ntohs(hdr.v2.len);
1292 DEBUG(D_receive) debug_printf("Detected PROXYv2 header, size %d (limit %d)\n",
1293 size, (int)sizeof(hdr));
1295 /* We should now have 16 octets (PROXY_V2_HEADER_SIZE), and we know the total
1296 amount that we need. Double-check that the size is not unreasonable, then
1298 if (size > sizeof(hdr))
1300 DEBUG(D_receive) debug_printf("PROXYv2 header size unreasonably large; security attack?\n");
1308 retmore = recv(fd, (uschar*)&hdr + ret, size-ret, 0);
1309 } while (retmore == -1 && errno == EINTR);
1313 DEBUG(D_receive) debug_printf("PROXYv2: have %d/%d required octets\n", ret, size);
1314 } while (ret < size);
1316 } /* end scope for getting rest of data for v2 */
1318 /* At this point: if PROXYv2, we've read the exact size required for all data;
1319 if PROXYv1 then we've read "less than required for any valid line" and should
1322 if (ret >= 16 && memcmp(&hdr.v2, v2sig, 12) == 0)
1324 uint8_t cmd = (hdr.v2.ver_cmd & 0x0f);
1328 case 0x01: /* PROXY command */
1331 case 0x11: /* TCPv4 address type */
1333 tmpaddr.sin_addr.s_addr = hdr.v2.addr.ip4.src_addr;
1334 inet_ntop(AF_INET, &tmpaddr.sin_addr, CS &tmpip, sizeof(tmpip));
1335 if (!string_is_ip_address(US tmpip, NULL))
1337 DEBUG(D_receive) debug_printf("Invalid %s source IP\n", iptype);
1340 proxy_local_address = sender_host_address;
1341 sender_host_address = string_copy(US tmpip);
1342 tmpport = ntohs(hdr.v2.addr.ip4.src_port);
1343 proxy_local_port = sender_host_port;
1344 sender_host_port = tmpport;
1345 /* Save dest ip/port */
1346 tmpaddr.sin_addr.s_addr = hdr.v2.addr.ip4.dst_addr;
1347 inet_ntop(AF_INET, &tmpaddr.sin_addr, CS &tmpip, sizeof(tmpip));
1348 if (!string_is_ip_address(US tmpip, NULL))
1350 DEBUG(D_receive) debug_printf("Invalid %s dest port\n", iptype);
1353 proxy_external_address = string_copy(US tmpip);
1354 tmpport = ntohs(hdr.v2.addr.ip4.dst_port);
1355 proxy_external_port = tmpport;
1357 case 0x21: /* TCPv6 address type */
1359 memmove(tmpaddr6.sin6_addr.s6_addr, hdr.v2.addr.ip6.src_addr, 16);
1360 inet_ntop(AF_INET6, &tmpaddr6.sin6_addr, CS &tmpip6, sizeof(tmpip6));
1361 if (!string_is_ip_address(US tmpip6, NULL))
1363 DEBUG(D_receive) debug_printf("Invalid %s source IP\n", iptype);
1366 proxy_local_address = sender_host_address;
1367 sender_host_address = string_copy(US tmpip6);
1368 tmpport = ntohs(hdr.v2.addr.ip6.src_port);
1369 proxy_local_port = sender_host_port;
1370 sender_host_port = tmpport;
1371 /* Save dest ip/port */
1372 memmove(tmpaddr6.sin6_addr.s6_addr, hdr.v2.addr.ip6.dst_addr, 16);
1373 inet_ntop(AF_INET6, &tmpaddr6.sin6_addr, CS &tmpip6, sizeof(tmpip6));
1374 if (!string_is_ip_address(US tmpip6, NULL))
1376 DEBUG(D_receive) debug_printf("Invalid %s dest port\n", iptype);
1379 proxy_external_address = string_copy(US tmpip6);
1380 tmpport = ntohs(hdr.v2.addr.ip6.dst_port);
1381 proxy_external_port = tmpport;
1385 debug_printf("Unsupported PROXYv2 connection type: 0x%02x\n",
1389 /* Unsupported protocol, keep local connection address */
1391 case 0x00: /* LOCAL command */
1392 /* Keep local connection address for LOCAL */
1397 debug_printf("Unsupported PROXYv2 command: 0x%x\n", cmd);
1401 else if (ret >= 8 && memcmp(hdr.v1.line, "PROXY", 5) == 0)
1405 uschar *sp; /* Utility variables follow */
1410 /* get the rest of the line */
1411 r2 = swallow_until_crlf(fd, (uschar*)&hdr, ret, sizeof(hdr)-ret);
1416 p = string_copy(hdr.v1.line);
1417 end = memchr(p, '\r', ret - 1);
1419 if (!end || (end == (uschar*)&hdr + ret) || end[1] != '\n')
1421 DEBUG(D_receive) debug_printf("Partial or invalid PROXY header\n");
1424 *end = '\0'; /* Terminate the string */
1425 size = end + 2 - p; /* Skip header + CRLF */
1426 DEBUG(D_receive) debug_printf("Detected PROXYv1 header\n");
1427 DEBUG(D_receive) debug_printf("Bytes read not within PROXY header: %d\n", ret - size);
1428 /* Step through the string looking for the required fields. Ensure
1429 strict adherence to required formatting, exit for any error. */
1431 if (!isspace(*(p++)))
1433 DEBUG(D_receive) debug_printf("Missing space after PROXY command\n");
1436 if (!Ustrncmp(p, CCS"TCP4", 4))
1438 else if (!Ustrncmp(p,CCS"TCP6", 4))
1440 else if (!Ustrncmp(p,CCS"UNKNOWN", 7))
1442 iptype = US"Unknown";
1447 DEBUG(D_receive) debug_printf("Invalid TCP type\n");
1451 p += Ustrlen(iptype);
1452 if (!isspace(*(p++)))
1454 DEBUG(D_receive) debug_printf("Missing space after TCP4/6 command\n");
1457 /* Find the end of the arg */
1458 if ((sp = Ustrchr(p, ' ')) == NULL)
1461 debug_printf("Did not find proxied src %s\n", iptype);
1465 if(!string_is_ip_address(p, NULL))
1468 debug_printf("Proxied src arg is not an %s address\n", iptype);
1471 proxy_local_address = sender_host_address;
1472 sender_host_address = p;
1474 if ((sp = Ustrchr(p, ' ')) == NULL)
1477 debug_printf("Did not find proxy dest %s\n", iptype);
1481 if(!string_is_ip_address(p, NULL))
1484 debug_printf("Proxy dest arg is not an %s address\n", iptype);
1487 proxy_external_address = p;
1489 if ((sp = Ustrchr(p, ' ')) == NULL)
1491 DEBUG(D_receive) debug_printf("Did not find proxied src port\n");
1495 tmp_port = strtol(CCS p, &endc, 10);
1496 if (*endc || tmp_port == 0)
1499 debug_printf("Proxied src port '%s' not an integer\n", p);
1502 proxy_local_port = sender_host_port;
1503 sender_host_port = tmp_port;
1505 if ((sp = Ustrchr(p, '\0')) == NULL)
1507 DEBUG(D_receive) debug_printf("Did not find proxy dest port\n");
1510 tmp_port = strtol(CCS p, &endc, 10);
1511 if (*endc || tmp_port == 0)
1514 debug_printf("Proxy dest port '%s' not an integer\n", p);
1517 proxy_external_port = tmp_port;
1518 /* Already checked for /r /n above. Good V1 header received. */
1522 /* Wrong protocol */
1523 DEBUG(D_receive) debug_printf("Invalid proxy protocol version negotiation\n");
1524 (void) swallow_until_crlf(fd, (uschar*)&hdr, ret, sizeof(hdr)-ret);
1530 debug_printf("Valid %s sender from Proxy Protocol header\n", iptype);
1531 yield = proxy_session;
1533 /* Don't flush any potential buffer contents. Any input on proxyfail
1534 should cause a synchronization failure */
1537 restore_socket_timeout(fd, get_ok, &tvtmp, vslen);
1542 sender_host_name = NULL;
1543 (void) host_name_lookup();
1544 host_build_sender_fullhost();
1548 f.proxy_session_failed = TRUE;
1550 debug_printf("Failure to extract proxied host, only QUIT allowed\n");
1557 /*************************************************
1558 * Read one command line *
1559 *************************************************/
1561 /* Strictly, SMTP commands coming over the net are supposed to end with CRLF.
1562 There are sites that don't do this, and in any case internal SMTP probably
1563 should check only for LF. Consequently, we check here for LF only. The line
1564 ends up with [CR]LF removed from its end. If we get an overlong line, treat as
1565 an unknown command. The command is read into the global smtp_cmd_buffer so that
1566 it is available via $smtp_command.
1568 The character reading routine sets up a timeout for each block actually read
1569 from the input (which may contain more than one command). We set up a special
1570 signal handler that closes down the session on a timeout. Control does not
1571 return when it runs.
1574 check_sync if TRUE, check synchronization rules if global option is TRUE
1575 buffer_lim maximum to buffer in lower layer
1577 Returns: a code identifying the command (enumerated above)
1581 smtp_read_command(BOOL check_sync, unsigned buffer_lim)
1585 BOOL hadnull = FALSE;
1587 had_command_timeout = 0;
1588 os_non_restarting_signal(SIGALRM, command_timeout_handler);
1590 while ((c = (receive_getc)(buffer_lim)) != '\n' && c != EOF)
1592 if (ptr >= SMTP_CMD_BUFFER_SIZE)
1594 os_non_restarting_signal(SIGALRM, sigalrm_handler);
1602 smtp_cmd_buffer[ptr++] = c;
1605 receive_linecount++; /* For BSMTP errors */
1606 os_non_restarting_signal(SIGALRM, sigalrm_handler);
1608 /* If hit end of file, return pseudo EOF command. Whether we have a
1609 part-line already read doesn't matter, since this is an error state. */
1611 if (c == EOF) return EOF_CMD;
1613 /* Remove any CR and white space at the end of the line, and terminate the
1616 while (ptr > 0 && isspace(smtp_cmd_buffer[ptr-1])) ptr--;
1617 smtp_cmd_buffer[ptr] = 0;
1619 DEBUG(D_receive) debug_printf("SMTP<< %s\n", smtp_cmd_buffer);
1621 /* NULLs are not allowed in SMTP commands */
1623 if (hadnull) return BADCHAR_CMD;
1625 /* Scan command list and return identity, having set the data pointer
1626 to the start of the actual data characters. Check for SMTP synchronization
1629 for (smtp_cmd_list * p = cmd_list; p < cmd_list_end; p++)
1631 #ifdef SUPPORT_PROXY
1632 /* Only allow QUIT command if Proxy Protocol parsing failed */
1633 if (proxy_session && f.proxy_session_failed && p->cmd != QUIT_CMD)
1637 && strncmpic(smtp_cmd_buffer, US p->name, p->len) == 0
1638 && ( smtp_cmd_buffer[p->len-1] == ':' /* "mail from:" or "rcpt to:" */
1639 || smtp_cmd_buffer[p->len] == 0
1640 || smtp_cmd_buffer[p->len] == ' '
1643 if (smtp_inptr < smtp_inend && /* Outstanding input */
1644 p->cmd < sync_cmd_limit && /* Command should sync */
1645 check_sync && /* Local flag set */
1646 smtp_enforce_sync && /* Global flag set */
1647 sender_host_address != NULL && /* Not local input */
1648 !f.sender_host_notsocket) /* Really is a socket */
1651 /* The variables $smtp_command and $smtp_command_argument point into the
1652 unmodified input buffer. A copy of the latter is taken for actual
1653 processing, so that it can be chopped up into separate parts if necessary,
1654 for example, when processing a MAIL command options such as SIZE that can
1655 follow the sender address. */
1657 smtp_cmd_argument = smtp_cmd_buffer + p->len;
1658 while (isspace(*smtp_cmd_argument)) smtp_cmd_argument++;
1659 Ustrcpy(smtp_data_buffer, smtp_cmd_argument);
1660 smtp_cmd_data = smtp_data_buffer;
1662 /* Count non-mail commands from those hosts that are controlled in this
1663 way. The default is all hosts. We don't waste effort checking the list
1664 until we get a non-mail command, but then cache the result to save checking
1665 again. If there's a DEFER while checking the host, assume it's in the list.
1667 Note that one instance of RSET, EHLO/HELO, and STARTTLS is allowed at the
1668 start of each incoming message by fiddling with the value in the table. */
1670 if (!p->is_mail_cmd)
1672 if (count_nonmail == TRUE_UNSET) count_nonmail =
1673 verify_check_host(&smtp_accept_max_nonmail_hosts) != FAIL;
1674 if (count_nonmail && ++nonmail_command_count > smtp_accept_max_nonmail)
1675 return TOO_MANY_NONMAIL_CMD;
1678 /* If there is data for a command that does not expect it, generate the
1681 return (p->has_arg || *smtp_cmd_data == 0)? p->cmd : BADARG_CMD;
1685 #ifdef SUPPORT_PROXY
1686 /* Only allow QUIT command if Proxy Protocol parsing failed */
1687 if (proxy_session && f.proxy_session_failed)
1688 return PROXY_FAIL_IGNORE_CMD;
1691 /* Enforce synchronization for unknown commands */
1693 if ( smtp_inptr < smtp_inend /* Outstanding input */
1694 && check_sync /* Local flag set */
1695 && smtp_enforce_sync /* Global flag set */
1696 && sender_host_address /* Not local input */
1697 && !f.sender_host_notsocket) /* Really is a socket */
1705 /*************************************************
1706 * Forced closedown of call *
1707 *************************************************/
1709 /* This function is called from log.c when Exim is dying because of a serious
1710 disaster, and also from some other places. If an incoming non-batched SMTP
1711 channel is open, it swallows the rest of the incoming message if in the DATA
1712 phase, sends the reply string, and gives an error to all subsequent commands
1713 except QUIT. The existence of an SMTP call is detected by the non-NULLness of
1717 message SMTP reply string to send, excluding the code
1723 smtp_closedown(uschar *message)
1725 if (!smtp_in || smtp_batched_input) return;
1726 receive_swallow_smtp();
1727 smtp_printf("421 %s\r\n", FALSE, message);
1729 for (;;) switch(smtp_read_command(FALSE, GETC_BUFFER_UNLIMITED))
1735 smtp_printf("221 %s closing connection\r\n", FALSE, smtp_active_hostname);
1740 smtp_printf("250 Reset OK\r\n", FALSE);
1744 smtp_printf("421 %s\r\n", FALSE, message);
1752 /*************************************************
1753 * Set up connection info for logging *
1754 *************************************************/
1756 /* This function is called when logging information about an SMTP connection.
1757 It sets up appropriate source information, depending on the type of connection.
1758 If sender_fullhost is NULL, we are at a very early stage of the connection;
1759 just use the IP address.
1762 Returns: a string describing the connection
1766 smtp_get_connection_info(void)
1768 const uschar * hostname = sender_fullhost
1769 ? sender_fullhost : sender_host_address;
1772 return string_sprintf("SMTP connection from %s", hostname);
1774 if (f.sender_host_unknown || f.sender_host_notsocket)
1775 return string_sprintf("SMTP connection from %s", sender_ident);
1778 return string_sprintf("SMTP connection from %s (via inetd)", hostname);
1780 if (LOGGING(incoming_interface) && interface_address)
1781 return string_sprintf("SMTP connection from %s I=[%s]:%d", hostname,
1782 interface_address, interface_port);
1784 return string_sprintf("SMTP connection from %s", hostname);
1790 /* Append TLS-related information to a log line
1793 g String under construction: allocated string to extend, or NULL
1795 Returns: Allocated string or NULL
1798 s_tlslog(gstring * g)
1800 if (LOGGING(tls_cipher) && tls_in.cipher)
1802 g = string_append(g, 2, US" X=", tls_in.cipher);
1803 #ifdef EXPERIMENTAL_TLS_RESUME
1804 if (LOGGING(tls_resumption) && tls_in.resumption & RESUME_USED)
1805 g = string_catn(g, US"*", 1);
1808 if (LOGGING(tls_certificate_verified) && tls_in.cipher)
1809 g = string_append(g, 2, US" CV=", tls_in.certificate_verified? "yes":"no");
1810 if (LOGGING(tls_peerdn) && tls_in.peerdn)
1811 g = string_append(g, 3, US" DN=\"", string_printing(tls_in.peerdn), US"\"");
1812 if (LOGGING(tls_sni) && tls_in.sni)
1813 g = string_append(g, 3, US" SNI=\"", string_printing(tls_in.sni), US"\"");
1818 /*************************************************
1819 * Log lack of MAIL if so configured *
1820 *************************************************/
1822 /* This function is called when an SMTP session ends. If the log selector
1823 smtp_no_mail is set, write a log line giving some details of what has happened
1824 in the SMTP session.
1831 smtp_log_no_mail(void)
1836 if (smtp_mailcmd_count > 0 || !LOGGING(smtp_no_mail))
1839 if (sender_host_authenticated)
1841 g = string_append(g, 2, US" A=", sender_host_authenticated);
1842 if (authenticated_id) g = string_append(g, 2, US":", authenticated_id);
1849 sep = smtp_connection_had[SMTP_HBUFF_SIZE-1] != SCH_NONE ? US" C=..." : US" C=";
1851 for (int i = smtp_ch_index; i < SMTP_HBUFF_SIZE; i++)
1852 if (smtp_connection_had[i] != SCH_NONE)
1854 g = string_append(g, 2, sep, smtp_names[smtp_connection_had[i]]);
1858 for (int i = 0; i < smtp_ch_index; i++)
1860 g = string_append(g, 2, sep, smtp_names[smtp_connection_had[i]]);
1864 if (!(s = string_from_gstring(g))) s = US"";
1866 log_write(0, LOG_MAIN, "no MAIL in %sSMTP connection from %s D=%s%s",
1867 f.tcp_in_fastopen ? f.tcp_in_fastopen_data ? US"TFO* " : US"TFO " : US"",
1868 host_and_ident(FALSE), string_timesince(&smtp_connection_start), s);
1872 /* Return list of recent smtp commands */
1877 gstring * list = NULL;
1880 for (int i = smtp_ch_index; i < SMTP_HBUFF_SIZE; i++)
1881 if (smtp_connection_had[i] != SCH_NONE)
1882 list = string_append_listele(list, ',', smtp_names[smtp_connection_had[i]]);
1884 for (int i = 0; i < smtp_ch_index; i++)
1885 list = string_append_listele(list, ',', smtp_names[smtp_connection_had[i]]);
1887 s = string_from_gstring(list);
1888 return s ? s : US"";
1894 /*************************************************
1895 * Check HELO line and set sender_helo_name *
1896 *************************************************/
1898 /* Check the format of a HELO line. The data for HELO/EHLO is supposed to be
1899 the domain name of the sending host, or an ip literal in square brackets. The
1900 argument is placed in sender_helo_name, which is in malloc store, because it
1901 must persist over multiple incoming messages. If helo_accept_junk is set, this
1902 host is permitted to send any old junk (needed for some broken hosts).
1903 Otherwise, helo_allow_chars can be used for rogue characters in general
1904 (typically people want to let in underscores).
1907 s the data portion of the line (already past any white space)
1909 Returns: TRUE or FALSE
1913 check_helo(uschar *s)
1916 uschar *end = s + Ustrlen(s);
1917 BOOL yield = fl.helo_accept_junk;
1919 /* Discard any previous helo name */
1921 sender_helo_name = NULL;
1923 /* Skip tests if junk is permitted. */
1927 /* Allow the new standard form for IPv6 address literals, namely,
1928 [IPv6:....], and because someone is bound to use it, allow an equivalent
1929 IPv4 form. Allow plain addresses as well. */
1936 if (strncmpic(s, US"[IPv6:", 6) == 0)
1937 yield = (string_is_ip_address(s+6, NULL) == 6);
1938 else if (strncmpic(s, US"[IPv4:", 6) == 0)
1939 yield = (string_is_ip_address(s+6, NULL) == 4);
1941 yield = (string_is_ip_address(s+1, NULL) != 0);
1946 /* Non-literals must be alpha, dot, hyphen, plus any non-valid chars
1947 that have been configured (usually underscore - sigh). */
1950 for (yield = TRUE; *s; s++)
1951 if (!isalnum(*s) && *s != '.' && *s != '-' &&
1952 Ustrchr(helo_allow_chars, *s) == NULL)
1958 /* Save argument if OK */
1960 if (yield) sender_helo_name = string_copy_perm(start, TRUE);
1968 /*************************************************
1969 * Extract SMTP command option *
1970 *************************************************/
1972 /* This function picks the next option setting off the end of smtp_cmd_data. It
1973 is called for MAIL FROM and RCPT TO commands, to pick off the optional ESMTP
1974 things that can appear there.
1977 name point this at the name
1978 value point this at the data string
1980 Returns: TRUE if found an option
1984 extract_option(uschar **name, uschar **value)
1987 uschar *v = smtp_cmd_data + Ustrlen(smtp_cmd_data) - 1;
1988 while (isspace(*v)) v--;
1990 while (v > smtp_cmd_data && *v != '=' && !isspace(*v))
1992 /* Take care to not stop at a space embedded in a quoted local-part */
1994 if (*v == '"') do v--; while (*v != '"' && v > smtp_cmd_data+1);
2001 while(isalpha(n[-1])) n--;
2002 /* RFC says SP, but TAB seen in wild and other major MTAs accept it */
2003 if (!isspace(n[-1])) return FALSE;
2009 if (v == smtp_cmd_data) return FALSE;
2021 /*************************************************
2022 * Reset for new message *
2023 *************************************************/
2025 /* This function is called whenever the SMTP session is reset from
2026 within either of the setup functions; also from the daemon loop.
2028 Argument: the stacking pool storage reset point
2033 smtp_reset(void *reset_point)
2035 recipients_list = NULL;
2036 rcpt_count = rcpt_defer_count = rcpt_fail_count =
2037 raw_recipients_count = recipients_count = recipients_list_max = 0;
2038 message_linecount = 0;
2040 acl_added_headers = NULL;
2041 acl_removed_headers = NULL;
2042 f.queue_only_policy = FALSE;
2043 rcpt_smtp_response = NULL;
2044 fl.rcpt_smtp_response_same = TRUE;
2045 fl.rcpt_in_progress = FALSE;
2046 f.deliver_freeze = FALSE; /* Can be set by ACL */
2047 freeze_tell = freeze_tell_config; /* Can be set by ACL */
2048 fake_response = OK; /* Can be set by ACL */
2049 #ifdef WITH_CONTENT_SCAN
2050 f.no_mbox_unspool = FALSE; /* Can be set by ACL */
2052 f.submission_mode = FALSE; /* Can be set by ACL */
2053 f.suppress_local_fixups = f.suppress_local_fixups_default; /* Can be set by ACL */
2054 f.active_local_from_check = local_from_check; /* Can be set by ACL */
2055 f.active_local_sender_retain = local_sender_retain; /* Can be set by ACL */
2056 sending_ip_address = NULL;
2057 return_path = sender_address = NULL;
2058 sender_data = NULL; /* Can be set by ACL */
2059 deliver_localpart_parent = deliver_localpart_orig = NULL;
2060 deliver_domain_parent = deliver_domain_orig = NULL;
2061 callout_address = NULL;
2062 submission_name = NULL; /* Can be set by ACL */
2063 raw_sender = NULL; /* After SMTP rewrite, before qualifying */
2064 sender_address_unrewritten = NULL; /* Set only after verify rewrite */
2065 sender_verified_list = NULL; /* No senders verified */
2066 memset(sender_address_cache, 0, sizeof(sender_address_cache));
2067 memset(sender_domain_cache, 0, sizeof(sender_domain_cache));
2069 authenticated_sender = NULL;
2070 #ifdef EXPERIMENTAL_BRIGHTMAIL
2072 bmi_verdicts = NULL;
2074 dnslist_domain = dnslist_matched = NULL;
2076 spf_header_comment = spf_received = spf_result = spf_smtp_comment = NULL;
2077 spf_result_guessed = FALSE;
2079 #ifndef DISABLE_DKIM
2080 dkim_cur_signer = dkim_signers =
2081 dkim_signing_domain = dkim_signing_selector = dkim_signatures = NULL;
2082 dkim_cur_signer = dkim_signers = dkim_signing_domain = dkim_signing_selector = NULL;
2083 f.dkim_disable_verify = FALSE;
2084 dkim_collect_input = 0;
2085 dkim_verify_overall = dkim_verify_status = dkim_verify_reason = NULL;
2086 dkim_key_length = 0;
2088 #ifdef SUPPORT_DMARC
2089 f.dmarc_has_been_checked = f.dmarc_disable_verify = f.dmarc_enable_forensic = FALSE;
2090 dmarc_domain_policy = dmarc_status = dmarc_status_text =
2091 dmarc_used_domain = NULL;
2093 #ifdef EXPERIMENTAL_ARC
2094 arc_state = arc_state_reason = NULL;
2095 arc_received_instance = 0;
2099 deliver_host = deliver_host_address = NULL; /* Can be set by ACL */
2100 #ifndef DISABLE_PRDR
2101 prdr_requested = FALSE;
2104 message_smtputf8 = FALSE;
2106 body_linecount = body_zerocount = 0;
2108 sender_rate = sender_rate_limit = sender_rate_period = NULL;
2109 ratelimiters_mail = NULL; /* Updated by ratelimit ACL condition */
2110 /* Note that ratelimiters_conn persists across resets. */
2112 /* Reset message ACL variables */
2116 /* The message body variables use malloc store. They may be set if this is
2117 not the first message in an SMTP session and the previous message caused them
2118 to be referenced in an ACL. */
2122 store_free(message_body);
2123 message_body = NULL;
2126 if (message_body_end)
2128 store_free(message_body_end);
2129 message_body_end = NULL;
2132 /* Warning log messages are also saved in malloc store. They are saved to avoid
2133 repetition in the same message, but it seems right to repeat them for different
2136 while (acl_warn_logged)
2138 string_item *this = acl_warn_logged;
2139 acl_warn_logged = acl_warn_logged->next;
2142 store_reset(reset_point);
2143 return store_mark();
2150 /*************************************************
2151 * Initialize for incoming batched SMTP message *
2152 *************************************************/
2154 /* This function is called from smtp_setup_msg() in the case when
2155 smtp_batched_input is true. This happens when -bS is used to pass a whole batch
2156 of messages in one file with SMTP commands between them. All errors must be
2157 reported by sending a message, and only MAIL FROM, RCPT TO, and DATA are
2158 relevant. After an error on a sender, or an invalid recipient, the remainder
2159 of the message is skipped. The value of received_protocol is already set.
2162 Returns: > 0 message successfully started (reached DATA)
2163 = 0 QUIT read or end of file reached
2164 < 0 should not occur
2168 smtp_setup_batch_msg(void)
2171 rmark reset_point = store_mark();
2173 /* Save the line count at the start of each transaction - single commands
2174 like HELO and RSET count as whole transactions. */
2176 bsmtp_transaction_linecount = receive_linecount;
2178 if ((receive_feof)()) return 0; /* Treat EOF as QUIT */
2180 cancel_cutthrough_connection(TRUE, US"smtp_setup_batch_msg");
2181 reset_point = smtp_reset(reset_point); /* Reset for start of message */
2183 /* Deal with SMTP commands. This loop is exited by setting done to a POSITIVE
2184 value. The values are 2 larger than the required yield of the function. */
2189 uschar *recipient = NULL;
2190 int start, end, sender_domain, recipient_domain;
2192 switch(smtp_read_command(FALSE, GETC_BUFFER_UNLIMITED))
2194 /* The HELO/EHLO commands set sender_address_helo if they have
2195 valid data; otherwise they are ignored, except that they do
2196 a reset of the state. */
2201 check_helo(smtp_cmd_data);
2205 cancel_cutthrough_connection(TRUE, US"RSET received");
2206 reset_point = smtp_reset(reset_point);
2207 bsmtp_transaction_linecount = receive_linecount;
2211 /* The MAIL FROM command requires an address as an operand. All we
2212 do here is to parse it for syntactic correctness. The form "<>" is
2213 a special case which converts into an empty string. The start/end
2214 pointers in the original are not used further for this address, as
2215 it is the canonical extracted address which is all that is kept. */
2218 smtp_mailcmd_count++; /* Count for no-mail log */
2219 if (sender_address != NULL)
2220 /* The function moan_smtp_batch() does not return. */
2221 moan_smtp_batch(smtp_cmd_buffer, "503 Sender already given");
2223 if (smtp_cmd_data[0] == 0)
2224 /* The function moan_smtp_batch() does not return. */
2225 moan_smtp_batch(smtp_cmd_buffer, "501 MAIL FROM must have an address operand");
2227 /* Reset to start of message */
2229 cancel_cutthrough_connection(TRUE, US"MAIL received");
2230 reset_point = smtp_reset(reset_point);
2232 /* Apply SMTP rewrite */
2234 raw_sender = ((rewrite_existflags & rewrite_smtp) != 0)?
2235 rewrite_one(smtp_cmd_data, rewrite_smtp|rewrite_smtp_sender, NULL, FALSE,
2236 US"", global_rewrite_rules) : smtp_cmd_data;
2238 /* Extract the address; the TRUE flag allows <> as valid */
2241 parse_extract_address(raw_sender, &errmess, &start, &end, &sender_domain,
2245 /* The function moan_smtp_batch() does not return. */
2246 moan_smtp_batch(smtp_cmd_buffer, "501 %s", errmess);
2248 sender_address = string_copy(raw_sender);
2250 /* Qualify unqualified sender addresses if permitted to do so. */
2253 && sender_address[0] != 0 && sender_address[0] != '@')
2254 if (f.allow_unqualified_sender)
2256 sender_address = rewrite_address_qualify(sender_address, FALSE);
2257 DEBUG(D_receive) debug_printf("unqualified address %s accepted "
2258 "and rewritten\n", raw_sender);
2260 /* The function moan_smtp_batch() does not return. */
2262 moan_smtp_batch(smtp_cmd_buffer, "501 sender address must contain "
2267 /* The RCPT TO command requires an address as an operand. All we do
2268 here is to parse it for syntactic correctness. There may be any number
2269 of RCPT TO commands, specifying multiple senders. We build them all into
2270 a data structure that is in argc/argv format. The start/end values
2271 given by parse_extract_address are not used, as we keep only the
2272 extracted address. */
2275 if (!sender_address)
2276 /* The function moan_smtp_batch() does not return. */
2277 moan_smtp_batch(smtp_cmd_buffer, "503 No sender yet given");
2279 if (smtp_cmd_data[0] == 0)
2280 /* The function moan_smtp_batch() does not return. */
2281 moan_smtp_batch(smtp_cmd_buffer,
2282 "501 RCPT TO must have an address operand");
2284 /* Check maximum number allowed */
2286 if (recipients_max > 0 && recipients_count + 1 > recipients_max)
2287 /* The function moan_smtp_batch() does not return. */
2288 moan_smtp_batch(smtp_cmd_buffer, "%s too many recipients",
2289 recipients_max_reject? "552": "452");
2291 /* Apply SMTP rewrite, then extract address. Don't allow "<>" as a
2292 recipient address */
2294 recipient = rewrite_existflags & rewrite_smtp
2295 ? rewrite_one(smtp_cmd_data, rewrite_smtp, NULL, FALSE, US"",
2296 global_rewrite_rules)
2299 recipient = parse_extract_address(recipient, &errmess, &start, &end,
2300 &recipient_domain, FALSE);
2303 /* The function moan_smtp_batch() does not return. */
2304 moan_smtp_batch(smtp_cmd_buffer, "501 %s", errmess);
2306 /* If the recipient address is unqualified, qualify it if permitted. Then
2307 add it to the list of recipients. */
2309 if (!recipient_domain)
2310 if (f.allow_unqualified_recipient)
2312 DEBUG(D_receive) debug_printf("unqualified address %s accepted\n",
2314 recipient = rewrite_address_qualify(recipient, TRUE);
2316 /* The function moan_smtp_batch() does not return. */
2318 moan_smtp_batch(smtp_cmd_buffer,
2319 "501 recipient address must contain a domain");
2321 receive_add_recipient(recipient, -1);
2325 /* The DATA command is legal only if it follows successful MAIL FROM
2326 and RCPT TO commands. This function is complete when a valid DATA
2327 command is encountered. */
2330 if (!sender_address || recipients_count <= 0)
2331 /* The function moan_smtp_batch() does not return. */
2332 if (!sender_address)
2333 moan_smtp_batch(smtp_cmd_buffer,
2334 "503 MAIL FROM:<sender> command must precede DATA");
2336 moan_smtp_batch(smtp_cmd_buffer,
2337 "503 RCPT TO:<recipient> must precede DATA");
2340 done = 3; /* DATA successfully achieved */
2341 message_ended = END_NOTENDED; /* Indicate in middle of message */
2346 /* The VRFY, EXPN, HELP, ETRN, and NOOP commands are ignored. */
2353 bsmtp_transaction_linecount = receive_linecount;
2364 /* The function moan_smtp_batch() does not return. */
2365 moan_smtp_batch(smtp_cmd_buffer, "501 Unexpected argument data");
2370 /* The function moan_smtp_batch() does not return. */
2371 moan_smtp_batch(smtp_cmd_buffer, "501 Unexpected NULL in SMTP command");
2376 /* The function moan_smtp_batch() does not return. */
2377 moan_smtp_batch(smtp_cmd_buffer, "500 Command unrecognized");
2382 return done - 2; /* Convert yield values */
2390 smtp_log_tls_fail(uschar * errstr)
2392 uschar * conn_info = smtp_get_connection_info();
2394 if (Ustrncmp(conn_info, US"SMTP ", 5) == 0) conn_info += 5;
2395 /* I'd like to get separated H= here, but too hard for now */
2397 log_write(0, LOG_MAIN, "TLS error on %s %s", conn_info, errstr);
2411 socklen_t len = sizeof(is_fastopen);
2413 /* The tinfo TCPOPT_FAST_OPEN bit seems unreliable, and we don't see state
2414 TCP_SYN_RCV (as of 12.1) so no idea about data-use. */
2416 if (getsockopt(fileno(smtp_out), IPPROTO_TCP, TCP_FASTOPEN, &is_fastopen, &len) == 0)
2421 debug_printf("TFO mode connection (TCP_FASTOPEN getsockopt)\n");
2422 f.tcp_in_fastopen = TRUE;
2425 else DEBUG(D_receive)
2426 debug_printf("TCP_INFO getsockopt: %s\n", strerror(errno));
2428 # elif defined(TCP_INFO)
2429 struct tcp_info tinfo;
2430 socklen_t len = sizeof(tinfo);
2432 if (getsockopt(fileno(smtp_out), IPPROTO_TCP, TCP_INFO, &tinfo, &len) == 0)
2433 # ifdef TCPI_OPT_SYN_DATA /* FreeBSD 11,12 do not seem to have this yet */
2434 if (tinfo.tcpi_options & TCPI_OPT_SYN_DATA)
2437 debug_printf("TFO mode connection (ACKd data-on-SYN)\n");
2438 f.tcp_in_fastopen_data = f.tcp_in_fastopen = TRUE;
2442 if (tinfo.tcpi_state == TCP_SYN_RECV) /* Not seen on FreeBSD 12.1 */
2445 debug_printf("TFO mode connection (state TCP_SYN_RECV)\n");
2446 f.tcp_in_fastopen = TRUE;
2448 else DEBUG(D_receive)
2449 debug_printf("TCP_INFO getsockopt: %s\n", strerror(errno));
2455 /*************************************************
2456 * Start an SMTP session *
2457 *************************************************/
2459 /* This function is called at the start of an SMTP session. Thereafter,
2460 smtp_setup_msg() is called to initiate each separate message. This
2461 function does host-specific testing, and outputs the banner line.
2464 Returns: FALSE if the session can not continue; something has
2465 gone wrong, or the connection to the host is blocked
2469 smtp_start_session(void)
2472 uschar *user_msg, *log_msg;
2477 gettimeofday(&smtp_connection_start, NULL);
2478 for (smtp_ch_index = 0; smtp_ch_index < SMTP_HBUFF_SIZE; smtp_ch_index++)
2479 smtp_connection_had[smtp_ch_index] = SCH_NONE;
2482 /* Default values for certain variables */
2484 fl.helo_seen = fl.esmtp = fl.helo_accept_junk = FALSE;
2485 smtp_mailcmd_count = 0;
2486 count_nonmail = TRUE_UNSET;
2487 synprot_error_count = unknown_command_count = nonmail_command_count = 0;
2488 smtp_delay_mail = smtp_rlm_base;
2489 fl.auth_advertised = FALSE;
2490 f.smtp_in_pipelining_advertised = f.smtp_in_pipelining_used = FALSE;
2491 f.pipelining_enable = TRUE;
2492 sync_cmd_limit = NON_SYNC_CMD_NON_PIPELINING;
2493 fl.smtp_exit_function_called = FALSE; /* For avoiding loop in not-quit exit */
2495 /* If receiving by -bs from a trusted user, or testing with -bh, we allow
2496 authentication settings from -oMaa to remain in force. */
2498 if (!host_checking && !f.sender_host_notsocket)
2499 sender_host_auth_pubname = sender_host_authenticated = NULL;
2500 authenticated_by = NULL;
2503 tls_in.ver = tls_in.cipher = tls_in.peerdn = NULL;
2504 tls_in.ourcert = tls_in.peercert = NULL;
2506 tls_in.ocsp = OCSP_NOT_REQ;
2507 fl.tls_advertised = FALSE;
2509 fl.dsn_advertised = FALSE;
2511 fl.smtputf8_advertised = FALSE;
2514 /* Reset ACL connection variables */
2518 /* Allow for trailing 0 in the command and data buffers. Tainted. */
2520 smtp_cmd_buffer = store_get_perm(2*SMTP_CMD_BUFFER_SIZE + 2, TRUE);
2522 smtp_cmd_buffer[0] = 0;
2523 smtp_data_buffer = smtp_cmd_buffer + SMTP_CMD_BUFFER_SIZE + 1;
2525 /* For batched input, the protocol setting can be overridden from the
2526 command line by a trusted caller. */
2528 if (smtp_batched_input)
2530 if (!received_protocol) received_protocol = US"local-bsmtp";
2533 /* For non-batched SMTP input, the protocol setting is forced here. It will be
2534 reset later if any of EHLO/AUTH/STARTTLS are received. */
2538 (sender_host_address ? protocols : protocols_local) [pnormal];
2540 /* Set up the buffer for inputting using direct read() calls, and arrange to
2541 call the local functions instead of the standard C ones. Place a NUL at the
2542 end of the buffer to safety-stop C-string reads from it. */
2544 if (!(smtp_inbuffer = US malloc(IN_BUFFER_SIZE)))
2545 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "malloc() failed for SMTP input buffer");
2546 smtp_inbuffer[IN_BUFFER_SIZE-1] = '\0';
2548 receive_getc = smtp_getc;
2549 receive_getbuf = smtp_getbuf;
2550 receive_get_cache = smtp_get_cache;
2551 receive_ungetc = smtp_ungetc;
2552 receive_feof = smtp_feof;
2553 receive_ferror = smtp_ferror;
2554 receive_smtp_buffered = smtp_buffered;
2555 smtp_inptr = smtp_inend = smtp_inbuffer;
2556 smtp_had_eof = smtp_had_error = 0;
2558 /* Set up the message size limit; this may be host-specific */
2560 thismessage_size_limit = expand_string_integer(message_size_limit, TRUE);
2561 if (expand_string_message)
2563 if (thismessage_size_limit == -1)
2564 log_write(0, LOG_MAIN|LOG_PANIC, "unable to expand message_size_limit: "
2565 "%s", expand_string_message);
2567 log_write(0, LOG_MAIN|LOG_PANIC, "invalid message_size_limit: "
2568 "%s", expand_string_message);
2569 smtp_closedown(US"Temporary local problem - please try later");
2573 /* When a message is input locally via the -bs or -bS options, sender_host_
2574 unknown is set unless -oMa was used to force an IP address, in which case it
2575 is checked like a real remote connection. When -bs is used from inetd, this
2576 flag is not set, causing the sending host to be checked. The code that deals
2577 with IP source routing (if configured) is never required for -bs or -bS and
2578 the flag sender_host_notsocket is used to suppress it.
2580 If smtp_accept_max and smtp_accept_reserve are set, keep some connections in
2581 reserve for certain hosts and/or networks. */
2583 if (!f.sender_host_unknown)
2586 BOOL reserved_host = FALSE;
2588 /* Look up IP options (source routing info) on the socket if this is not an
2589 -oMa "host", and if any are found, log them and drop the connection.
2591 Linux (and others now, see below) is different to everyone else, so there
2592 has to be some conditional compilation here. Versions of Linux before 2.1.15
2593 used a structure whose name was "options". Somebody finally realized that
2594 this name was silly, and it got changed to "ip_options". I use the
2595 newer name here, but there is a fudge in the script that sets up os.h
2596 to define a macro in older Linux systems.
2598 Sigh. Linux is a fast-moving target. Another generation of Linux uses
2599 glibc 2, which has chosen ip_opts for the structure name. This is now
2600 really a glibc thing rather than a Linux thing, so the condition name
2601 has been changed to reflect this. It is relevant also to GNU/Hurd.
2603 Mac OS 10.x (Darwin) is like the later glibc versions, but without the
2604 setting of the __GLIBC__ macro, so we can't detect it automatically. There's
2605 a special macro defined in the os.h file.
2607 Some DGUX versions on older hardware appear not to support IP options at
2608 all, so there is now a general macro which can be set to cut out this
2611 How to do this properly in IPv6 is not yet known. */
2613 #if !HAVE_IPV6 && !defined(NO_IP_OPTIONS)
2615 #ifdef GLIBC_IP_OPTIONS
2616 #if (!defined __GLIBC__) || (__GLIBC__ < 2)
2621 #elif defined DARWIN_IP_OPTIONS
2627 if (!host_checking && !f.sender_host_notsocket)
2630 EXIM_SOCKLEN_T optlen = sizeof(struct ip_options) + MAX_IPOPTLEN;
2631 struct ip_options *ipopt = store_get(optlen, FALSE);
2633 struct ip_opts ipoptblock;
2634 struct ip_opts *ipopt = &ipoptblock;
2635 EXIM_SOCKLEN_T optlen = sizeof(ipoptblock);
2637 struct ipoption ipoptblock;
2638 struct ipoption *ipopt = &ipoptblock;
2639 EXIM_SOCKLEN_T optlen = sizeof(ipoptblock);
2642 /* Occasional genuine failures of getsockopt() have been seen - for
2643 example, "reset by peer". Therefore, just log and give up on this
2644 call, unless the error is ENOPROTOOPT. This error is given by systems
2645 that have the interfaces but not the mechanism - e.g. GNU/Hurd at the time
2646 of writing. So for that error, carry on - we just can't do an IP options
2649 DEBUG(D_receive) debug_printf("checking for IP options\n");
2651 if (getsockopt(fileno(smtp_out), IPPROTO_IP, IP_OPTIONS, US (ipopt),
2654 if (errno != ENOPROTOOPT)
2656 log_write(0, LOG_MAIN, "getsockopt() failed from %s: %s",
2657 host_and_ident(FALSE), strerror(errno));
2658 smtp_printf("451 SMTP service not available\r\n", FALSE);
2663 /* Deal with any IP options that are set. On the systems I have looked at,
2664 the value of MAX_IPOPTLEN has been 40, meaning that there should never be
2665 more logging data than will fit in big_buffer. Nevertheless, after somebody
2666 questioned this code, I've added in some paranoid checking. */
2668 else if (optlen > 0)
2670 uschar *p = big_buffer;
2671 uschar *pend = big_buffer + big_buffer_size;
2674 struct in_addr addr;
2677 uschar *optstart = US (ipopt->__data);
2679 uschar *optstart = US (ipopt->ip_opts);
2681 uschar *optstart = US (ipopt->ipopt_list);
2684 DEBUG(D_receive) debug_printf("IP options exist\n");
2686 Ustrcpy(p, "IP options on incoming call:");
2689 for (uschar * opt = optstart; opt && opt < US (ipopt) + optlen; )
2702 if (!string_format(p, pend-p, " %s [@%s",
2703 (*opt == IPOPT_SSRR)? "SSRR" : "LSRR",
2705 inet_ntoa(*((struct in_addr *)(&(ipopt->faddr))))))
2707 inet_ntoa(ipopt->ip_dst)))
2709 inet_ntoa(ipopt->ipopt_dst)))
2717 optcount = (opt[1] - 3) / sizeof(struct in_addr);
2719 while (optcount-- > 0)
2721 memcpy(&addr, adptr, sizeof(addr));
2722 if (!string_format(p, pend - p - 1, "%s%s",
2723 (optcount == 0)? ":" : "@", inet_ntoa(addr)))
2729 adptr += sizeof(struct in_addr);
2737 if (pend - p < 4 + 3*opt[1]) { opt = NULL; break; }
2740 for (int i = 0; i < opt[1]; i++)
2741 p += sprintf(CS p, "%2.2x ", opt[i]);
2749 log_write(0, LOG_MAIN, "%s", big_buffer);
2751 /* Refuse any call with IP options. This is what tcpwrappers 7.5 does. */
2753 log_write(0, LOG_MAIN|LOG_REJECT,
2754 "connection from %s refused (IP options)", host_and_ident(FALSE));
2756 smtp_printf("554 SMTP service not available\r\n", FALSE);
2760 /* Length of options = 0 => there are no options */
2762 else DEBUG(D_receive) debug_printf("no IP options found\n");
2764 #endif /* HAVE_IPV6 && !defined(NO_IP_OPTIONS) */
2766 /* Set keep-alive in socket options. The option is on by default. This
2767 setting is an attempt to get rid of some hanging connections that stick in
2768 read() when the remote end (usually a dialup) goes away. */
2770 if (smtp_accept_keepalive && !f.sender_host_notsocket)
2771 ip_keepalive(fileno(smtp_out), sender_host_address, FALSE);
2773 /* If the current host matches host_lookup, set the name by doing a
2774 reverse lookup. On failure, sender_host_name will be NULL and
2775 host_lookup_failed will be TRUE. This may or may not be serious - optional
2778 if (verify_check_host(&host_lookup) == OK)
2780 (void)host_name_lookup();
2781 host_build_sender_fullhost();
2784 /* Delay this until we have the full name, if it is looked up. */
2786 set_process_info("handling incoming connection from %s",
2787 host_and_ident(FALSE));
2789 /* Expand smtp_receive_timeout, if needed */
2791 if (smtp_receive_timeout_s)
2794 if ( !(exp = expand_string(smtp_receive_timeout_s))
2796 || (smtp_receive_timeout = readconf_readtime(exp, 0, FALSE)) < 0
2798 log_write(0, LOG_MAIN|LOG_PANIC,
2799 "bad value for smtp_receive_timeout: '%s'", exp ? exp : US"");
2802 /* Test for explicit connection rejection */
2804 if (verify_check_host(&host_reject_connection) == OK)
2806 log_write(L_connection_reject, LOG_MAIN|LOG_REJECT, "refused connection "
2807 "from %s (host_reject_connection)", host_and_ident(FALSE));
2808 smtp_printf("554 SMTP service not available\r\n", FALSE);
2812 /* Test with TCP Wrappers if so configured. There is a problem in that
2813 hosts_ctl() returns 0 (deny) under a number of system failure circumstances,
2814 such as disks dying. In these cases, it is desirable to reject with a 4xx
2815 error instead of a 5xx error. There isn't a "right" way to detect such
2816 problems. The following kludge is used: errno is zeroed before calling
2817 hosts_ctl(). If the result is "reject", a 5xx error is given only if the
2818 value of errno is 0 or ENOENT (which happens if /etc/hosts.{allow,deny} does
2821 #ifdef USE_TCP_WRAPPERS
2823 if (!(tcp_wrappers_name = expand_string(tcp_wrappers_daemon_name)))
2824 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "Expansion of \"%s\" "
2825 "(tcp_wrappers_name) failed: %s", string_printing(tcp_wrappers_name),
2826 expand_string_message);
2828 if (!hosts_ctl(tcp_wrappers_name,
2829 sender_host_name ? CS sender_host_name : STRING_UNKNOWN,
2830 sender_host_address ? CS sender_host_address : STRING_UNKNOWN,
2831 sender_ident ? CS sender_ident : STRING_UNKNOWN))
2833 if (errno == 0 || errno == ENOENT)
2835 HDEBUG(D_receive) debug_printf("tcp wrappers rejection\n");
2836 log_write(L_connection_reject,
2837 LOG_MAIN|LOG_REJECT, "refused connection from %s "
2838 "(tcp wrappers)", host_and_ident(FALSE));
2839 smtp_printf("554 SMTP service not available\r\n", FALSE);
2843 int save_errno = errno;
2844 HDEBUG(D_receive) debug_printf("tcp wrappers rejected with unexpected "
2845 "errno value %d\n", save_errno);
2846 log_write(L_connection_reject,
2847 LOG_MAIN|LOG_REJECT, "temporarily refused connection from %s "
2848 "(tcp wrappers errno=%d)", host_and_ident(FALSE), save_errno);
2849 smtp_printf("451 Temporary local problem - please try later\r\n", FALSE);
2855 /* Check for reserved slots. The value of smtp_accept_count has already been
2856 incremented to include this process. */
2858 if (smtp_accept_max > 0 &&
2859 smtp_accept_count > smtp_accept_max - smtp_accept_reserve)
2861 if ((rc = verify_check_host(&smtp_reserve_hosts)) != OK)
2863 log_write(L_connection_reject,
2864 LOG_MAIN, "temporarily refused connection from %s: not in "
2865 "reserve list: connected=%d max=%d reserve=%d%s",
2866 host_and_ident(FALSE), smtp_accept_count - 1, smtp_accept_max,
2867 smtp_accept_reserve, (rc == DEFER)? " (lookup deferred)" : "");
2868 smtp_printf("421 %s: Too many concurrent SMTP connections; "
2869 "please try again later\r\n", FALSE, smtp_active_hostname);
2872 reserved_host = TRUE;
2875 /* If a load level above which only messages from reserved hosts are
2876 accepted is set, check the load. For incoming calls via the daemon, the
2877 check is done in the superior process if there are no reserved hosts, to
2878 save a fork. In all cases, the load average will already be available
2879 in a global variable at this point. */
2881 if (smtp_load_reserve >= 0 &&
2882 load_average > smtp_load_reserve &&
2884 verify_check_host(&smtp_reserve_hosts) != OK)
2886 log_write(L_connection_reject,
2887 LOG_MAIN, "temporarily refused connection from %s: not in "
2888 "reserve list and load average = %.2f", host_and_ident(FALSE),
2889 (double)load_average/1000.0);
2890 smtp_printf("421 %s: Too much load; please try again later\r\n", FALSE,
2891 smtp_active_hostname);
2895 /* Determine whether unqualified senders or recipients are permitted
2896 for this host. Unfortunately, we have to do this every time, in order to
2897 set the flags so that they can be inspected when considering qualifying
2898 addresses in the headers. For a site that permits no qualification, this
2899 won't take long, however. */
2901 f.allow_unqualified_sender =
2902 verify_check_host(&sender_unqualified_hosts) == OK;
2904 f.allow_unqualified_recipient =
2905 verify_check_host(&recipient_unqualified_hosts) == OK;
2907 /* Determine whether HELO/EHLO is required for this host. The requirement
2908 can be hard or soft. */
2910 fl.helo_required = verify_check_host(&helo_verify_hosts) == OK;
2911 if (!fl.helo_required)
2912 fl.helo_verify = verify_check_host(&helo_try_verify_hosts) == OK;
2914 /* Determine whether this hosts is permitted to send syntactic junk
2915 after a HELO or EHLO command. */
2917 fl.helo_accept_junk = verify_check_host(&helo_accept_junk_hosts) == OK;
2920 /* For batch SMTP input we are now done. */
2922 if (smtp_batched_input) return TRUE;
2924 /* If valid Proxy Protocol source is connecting, set up session.
2925 * Failure will not allow any SMTP function other than QUIT. */
2927 #ifdef SUPPORT_PROXY
2928 proxy_session = FALSE;
2929 f.proxy_session_failed = FALSE;
2930 if (check_proxy_protocol_host())
2931 setup_proxy_protocol_host();
2934 /* Start up TLS if tls_on_connect is set. This is for supporting the legacy
2935 smtps port for use with older style SSL MTAs. */
2938 if (tls_in.on_connect)
2940 if (tls_server_start(tls_require_ciphers, &user_msg) != OK)
2941 return smtp_log_tls_fail(user_msg);
2942 cmd_list[CMD_LIST_TLS_AUTH].is_mail_cmd = TRUE;
2946 /* Run the connect ACL if it exists */
2949 if (acl_smtp_connect)
2952 if ((rc = acl_check(ACL_WHERE_CONNECT, NULL, acl_smtp_connect, &user_msg,
2955 (void) smtp_handle_acl_fail(ACL_WHERE_CONNECT, rc, user_msg, log_msg);
2960 /* Output the initial message for a two-way SMTP connection. It may contain
2961 newlines, which then cause a multi-line response to be given. */
2963 code = US"220"; /* Default status code */
2964 esc = US""; /* Default extended status code */
2965 esclen = 0; /* Length of esc */
2969 if (!(s = expand_string(smtp_banner)))
2970 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "Expansion of \"%s\" (smtp_banner) "
2971 "failed: %s", smtp_banner, expand_string_message);
2977 smtp_message_code(&code, &codelen, &s, NULL, TRUE);
2981 esclen = codelen - 4;
2985 /* Remove any terminating newlines; might as well remove trailing space too */
2988 while (p > s && isspace(p[-1])) p--;
2991 /* It seems that CC:Mail is braindead, and assumes that the greeting message
2992 is all contained in a single IP packet. The original code wrote out the
2993 greeting using several calls to fprint/fputc, and on busy servers this could
2994 cause it to be split over more than one packet - which caused CC:Mail to fall
2995 over when it got the second part of the greeting after sending its first
2996 command. Sigh. To try to avoid this, build the complete greeting message
2997 first, and output it in one fell swoop. This gives a better chance of it
2998 ending up as a single packet. */
3000 ss = string_get(256);
3003 do /* At least once, in case we have an empty string */
3006 uschar *linebreak = Ustrchr(p, '\n');
3007 ss = string_catn(ss, code, 3);
3011 ss = string_catn(ss, US" ", 1);
3015 len = linebreak - p;
3016 ss = string_catn(ss, US"-", 1);
3018 ss = string_catn(ss, esc, esclen);
3019 ss = string_catn(ss, p, len);
3020 ss = string_catn(ss, US"\r\n", 2);
3026 /* Before we write the banner, check that there is no input pending, unless
3027 this synchronisation check is disabled. */
3029 #ifndef DISABLE_PIPE_CONNECT
3030 fl.pipe_connect_acceptable =
3031 sender_host_address && verify_check_host(&pipe_connect_advertise_hosts) == OK;
3034 if (fl.pipe_connect_acceptable)
3035 f.smtp_in_early_pipe_used = TRUE;
3041 unsigned n = smtp_inend - smtp_inptr;
3044 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP protocol "
3045 "synchronization error (input sent without waiting for greeting): "
3046 "rejected connection from %s input=\"%s\"", host_and_ident(TRUE),
3047 string_printing(string_copyn(smtp_inptr, n)));
3048 smtp_printf("554 SMTP synchronization error\r\n", FALSE);
3052 /* Now output the banner */
3053 /*XXX the ehlo-resp code does its own tls/nontls bit. Maybe subroutine that? */
3056 #ifndef DISABLE_PIPE_CONNECT
3057 fl.pipe_connect_acceptable && pipeline_connect_sends(),
3061 string_from_gstring(ss));
3063 /* Attempt to see if we sent the banner before the last ACK of the 3-way
3064 handshake arrived. If so we must have managed a TFO. */
3067 if (sender_host_address && !f.sender_host_notsocket) tfo_in_check();
3077 /*************************************************
3078 * Handle SMTP syntax and protocol errors *
3079 *************************************************/
3081 /* Write to the log for SMTP syntax errors in incoming commands, if configured
3082 to do so. Then transmit the error response. The return value depends on the
3083 number of syntax and protocol errors in this SMTP session.
3086 type error type, given as a log flag bit
3087 code response code; <= 0 means don't send a response
3088 data data to reflect in the response (can be NULL)
3089 errmess the error message
3091 Returns: -1 limit of syntax/protocol errors NOT exceeded
3092 +1 limit of syntax/protocol errors IS exceeded
3094 These values fit in with the values of the "done" variable in the main
3095 processing loop in smtp_setup_msg(). */
3098 synprot_error(int type, int code, uschar *data, uschar *errmess)
3102 log_write(type, LOG_MAIN, "SMTP %s error in \"%s\" %s %s",
3103 (type == L_smtp_syntax_error)? "syntax" : "protocol",
3104 string_printing(smtp_cmd_buffer), host_and_ident(TRUE), errmess);
3106 if (++synprot_error_count > smtp_max_synprot_errors)
3109 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
3110 "syntax or protocol errors (last command was \"%s\")",
3111 host_and_ident(FALSE), string_printing(smtp_cmd_buffer));
3116 smtp_printf("%d%c%s%s%s\r\n", FALSE, code, yield == 1 ? '-' : ' ',
3117 data ? data : US"", data ? US": " : US"", errmess);
3119 smtp_printf("%d Too many syntax or protocol errors\r\n", FALSE, code);
3128 /*************************************************
3129 * Send SMTP response, possibly multiline *
3130 *************************************************/
3132 /* There are, it seems, broken clients out there that cannot handle multiline
3133 responses. If no_multiline_responses is TRUE (it can be set from an ACL), we
3134 output nothing for non-final calls, and only the first line for anything else.
3137 code SMTP code, may involve extended status codes
3138 codelen length of smtp code; if > 4 there's an ESC
3139 final FALSE if the last line isn't the final line
3140 msg message text, possibly containing newlines
3146 smtp_respond(uschar* code, int codelen, BOOL final, uschar *msg)
3151 if (!final && f.no_multiline_responses) return;
3156 esclen = codelen - 4;
3159 /* If this is the first output for a (non-batch) RCPT command, see if all RCPTs
3160 have had the same. Note: this code is also present in smtp_printf(). It would
3161 be tidier to have it only in one place, but when it was added, it was easier to
3162 do it that way, so as not to have to mess with the code for the RCPT command,
3163 which sometimes uses smtp_printf() and sometimes smtp_respond(). */
3165 if (fl.rcpt_in_progress)
3167 if (rcpt_smtp_response == NULL)
3168 rcpt_smtp_response = string_copy(msg);
3169 else if (fl.rcpt_smtp_response_same &&
3170 Ustrcmp(rcpt_smtp_response, msg) != 0)
3171 fl.rcpt_smtp_response_same = FALSE;
3172 fl.rcpt_in_progress = FALSE;
3175 /* Now output the message, splitting it up into multiple lines if necessary.
3176 We only handle pipelining these responses as far as nonfinal/final groups,
3177 not the whole MAIL/RCPT/DATA response set. */
3181 uschar *nl = Ustrchr(msg, '\n');
3184 smtp_printf("%.3s%c%.*s%s\r\n", !final, code, final ? ' ':'-', esclen, esc, msg);
3187 else if (nl[1] == 0 || f.no_multiline_responses)
3189 smtp_printf("%.3s%c%.*s%.*s\r\n", !final, code, final ? ' ':'-', esclen, esc,
3190 (int)(nl - msg), msg);
3195 smtp_printf("%.3s-%.*s%.*s\r\n", TRUE, code, esclen, esc, (int)(nl - msg), msg);
3197 while (isspace(*msg)) msg++;
3205 /*************************************************
3206 * Parse user SMTP message *
3207 *************************************************/
3209 /* This function allows for user messages overriding the response code details
3210 by providing a suitable response code string at the start of the message
3211 user_msg. Check the message for starting with a response code and optionally an
3212 extended status code. If found, check that the first digit is valid, and if so,
3213 change the code pointer and length to use the replacement. An invalid code
3214 causes a panic log; in this case, if the log messages is the same as the user
3215 message, we must also adjust the value of the log message to show the code that
3216 is actually going to be used (the original one).
3218 This function is global because it is called from receive.c as well as within
3221 Note that the code length returned includes the terminating whitespace
3222 character, which is always included in the regex match.
3225 code SMTP code, may involve extended status codes
3226 codelen length of smtp code; if > 4 there's an ESC
3228 log_msg optional log message, to be adjusted with the new SMTP code
3229 check_valid if true, verify the response code
3235 smtp_message_code(uschar **code, int *codelen, uschar **msg, uschar **log_msg,
3241 if (!msg || !*msg) return;
3243 if ((n = pcre_exec(regex_smtp_code, NULL, CS *msg, Ustrlen(*msg), 0,
3244 PCRE_EOPT, ovector, sizeof(ovector)/sizeof(int))) < 0) return;
3246 if (check_valid && (*msg)[0] != (*code)[0])
3248 log_write(0, LOG_MAIN|LOG_PANIC, "configured error code starts with "
3249 "incorrect digit (expected %c) in \"%s\"", (*code)[0], *msg);
3250 if (log_msg != NULL && *log_msg == *msg)
3251 *log_msg = string_sprintf("%s %s", *code, *log_msg + ovector[1]);
3256 *codelen = ovector[1]; /* Includes final space */
3258 *msg += ovector[1]; /* Chop the code off the message */
3265 /*************************************************
3266 * Handle an ACL failure *
3267 *************************************************/
3269 /* This function is called when acl_check() fails. As well as calls from within
3270 this module, it is called from receive.c for an ACL after DATA. It sorts out
3271 logging the incident, and sends the error response. A message containing
3272 newlines is turned into a multiline SMTP response, but for logging, only the
3275 There's a table of default permanent failure response codes to use in
3276 globals.c, along with the table of names. VFRY is special. Despite RFC1123 it
3277 defaults disabled in Exim. However, discussion in connection with RFC 821bis
3278 (aka RFC 2821) has concluded that the response should be 252 in the disabled
3279 state, because there are broken clients that try VRFY before RCPT. A 5xx
3280 response should be given only when the address is positively known to be
3281 undeliverable. Sigh. We return 252 if there is no VRFY ACL or it provides
3282 no explicit code, but if there is one we let it know best.
3283 Also, for ETRN, 458 is given on refusal, and for AUTH, 503.
3285 From Exim 4.63, it is possible to override the response code details by
3286 providing a suitable response code string at the start of the message provided
3287 in user_msg. The code's first digit is checked for validity.
3290 where where the ACL was called from
3292 user_msg a message that can be included in an SMTP response
3293 log_msg a message for logging
3295 Returns: 0 in most cases
3296 2 if the failure code was FAIL_DROP, in which case the
3297 SMTP connection should be dropped (this value fits with the
3298 "done" variable in smtp_setup_msg() below)
3302 smtp_handle_acl_fail(int where, int rc, uschar *user_msg, uschar *log_msg)
3304 BOOL drop = rc == FAIL_DROP;
3308 uschar *sender_info = US"";
3310 #ifdef WITH_CONTENT_SCAN
3311 where == ACL_WHERE_MIME ? US"during MIME ACL checks" :
3313 where == ACL_WHERE_PREDATA ? US"DATA" :
3314 where == ACL_WHERE_DATA ? US"after DATA" :
3315 #ifndef DISABLE_PRDR
3316 where == ACL_WHERE_PRDR ? US"after DATA PRDR" :
3319 string_sprintf("%s %s", acl_wherenames[where], smtp_cmd_data) :
3320 string_sprintf("%s in \"connect\" ACL", acl_wherenames[where]);
3322 if (drop) rc = FAIL;
3324 /* Set the default SMTP code, and allow a user message to change it. */
3326 smtp_code = rc == FAIL ? acl_wherecodes[where] : US"451";
3327 smtp_message_code(&smtp_code, &codelen, &user_msg, &log_msg,
3328 where != ACL_WHERE_VRFY);
3330 /* We used to have sender_address here; however, there was a bug that was not
3331 updating sender_address after a rewrite during a verify. When this bug was
3332 fixed, sender_address at this point became the rewritten address. I'm not sure
3333 this is what should be logged, so I've changed to logging the unrewritten
3334 address to retain backward compatibility. */
3336 #ifndef WITH_CONTENT_SCAN
3337 if (where == ACL_WHERE_RCPT || where == ACL_WHERE_DATA)
3339 if (where == ACL_WHERE_RCPT || where == ACL_WHERE_DATA || where == ACL_WHERE_MIME)
3342 sender_info = string_sprintf("F=<%s>%s%s%s%s ",
3343 sender_address_unrewritten ? sender_address_unrewritten : sender_address,
3344 sender_host_authenticated ? US" A=" : US"",
3345 sender_host_authenticated ? sender_host_authenticated : US"",
3346 sender_host_authenticated && authenticated_id ? US":" : US"",
3347 sender_host_authenticated && authenticated_id ? authenticated_id : US""
3351 /* If there's been a sender verification failure with a specific message, and
3352 we have not sent a response about it yet, do so now, as a preliminary line for
3353 failures, but not defers. However, always log it for defer, and log it for fail
3354 unless the sender_verify_fail log selector has been turned off. */
3356 if (sender_verified_failed &&
3357 !testflag(sender_verified_failed, af_sverify_told))
3359 BOOL save_rcpt_in_progress = fl.rcpt_in_progress;
3360 fl.rcpt_in_progress = FALSE; /* So as not to treat these as the error */
3362 setflag(sender_verified_failed, af_sverify_told);
3364 if (rc != FAIL || LOGGING(sender_verify_fail))
3365 log_write(0, LOG_MAIN|LOG_REJECT, "%s sender verify %s for <%s>%s",
3366 host_and_ident(TRUE),
3367 ((sender_verified_failed->special_action & 255) == DEFER)? "defer":"fail",
3368 sender_verified_failed->address,
3369 (sender_verified_failed->message == NULL)? US"" :
3370 string_sprintf(": %s", sender_verified_failed->message));
3372 if (rc == FAIL && sender_verified_failed->user_message)
3373 smtp_respond(smtp_code, codelen, FALSE, string_sprintf(
3374 testflag(sender_verified_failed, af_verify_pmfail)?
3375 "Postmaster verification failed while checking <%s>\n%s\n"
3376 "Several RFCs state that you are required to have a postmaster\n"
3377 "mailbox for each mail domain. This host does not accept mail\n"
3378 "from domains whose servers reject the postmaster address."
3380 testflag(sender_verified_failed, af_verify_nsfail)?
3381 "Callback setup failed while verifying <%s>\n%s\n"
3382 "The initial connection, or a HELO or MAIL FROM:<> command was\n"
3383 "rejected. Refusing MAIL FROM:<> does not help fight spam, disregards\n"
3384 "RFC requirements, and stops you from receiving standard bounce\n"
3385 "messages. This host does not accept mail from domains whose servers\n"
3388 "Verification failed for <%s>\n%s",
3389 sender_verified_failed->address,
3390 sender_verified_failed->user_message));
3392 fl.rcpt_in_progress = save_rcpt_in_progress;
3395 /* Sort out text for logging */
3397 log_msg = log_msg ? string_sprintf(": %s", log_msg) : US"";
3398 if ((lognl = Ustrchr(log_msg, '\n'))) *lognl = 0;
3400 /* Send permanent failure response to the command, but the code used isn't
3401 always a 5xx one - see comments at the start of this function. If the original
3402 rc was FAIL_DROP we drop the connection and yield 2. */
3405 smtp_respond(smtp_code, codelen, TRUE,
3406 user_msg ? user_msg : US"Administrative prohibition");
3408 /* Send temporary failure response to the command. Don't give any details,
3409 unless acl_temp_details is set. This is TRUE for a callout defer, a "defer"
3410 verb, and for a header verify when smtp_return_error_details is set.
3412 This conditional logic is all somewhat of a mess because of the odd
3413 interactions between temp_details and return_error_details. One day it should
3414 be re-implemented in a tidier fashion. */
3417 if (f.acl_temp_details && user_msg)
3419 if ( smtp_return_error_details
3420 && sender_verified_failed
3421 && sender_verified_failed->message
3423 smtp_respond(smtp_code, codelen, FALSE, sender_verified_failed->message);
3425 smtp_respond(smtp_code, codelen, TRUE, user_msg);
3428 smtp_respond(smtp_code, codelen, TRUE,
3429 US"Temporary local problem - please try later");
3431 /* Log the incident to the logs that are specified by log_reject_target
3432 (default main, reject). This can be empty to suppress logging of rejections. If
3433 the connection is not forcibly to be dropped, return 0. Otherwise, log why it
3434 is closing if required and return 2. */
3436 if (log_reject_target != 0)
3439 gstring * g = s_tlslog(NULL);
3440 uschar * tls = string_from_gstring(g);
3441 if (!tls) tls = US"";
3443 uschar * tls = US"";
3445 log_write(where == ACL_WHERE_CONNECT ? L_connection_reject : 0,
3446 log_reject_target, "%s%s%s %s%srejected %s%s",
3447 LOGGING(dnssec) && sender_host_dnssec ? US" DS" : US"",
3448 host_and_ident(TRUE),
3451 rc == FAIL ? US"" : US"temporarily ",
3455 if (!drop) return 0;
3457 log_write(L_smtp_connection, LOG_MAIN, "%s closed by DROP in ACL",
3458 smtp_get_connection_info());
3460 /* Run the not-quit ACL, but without any custom messages. This should not be a
3461 problem, because we get here only if some other ACL has issued "drop", and
3462 in that case, *its* custom messages will have been used above. */
3464 smtp_notquit_exit(US"acl-drop", NULL, NULL);
3471 /*************************************************
3472 * Handle SMTP exit when QUIT is not given *
3473 *************************************************/
3475 /* This function provides a logging/statistics hook for when an SMTP connection
3476 is dropped on the floor or the other end goes away. It's a global function
3477 because it's called from receive.c as well as this module. As well as running
3478 the NOTQUIT ACL, if there is one, this function also outputs a final SMTP
3479 response, either with a custom message from the ACL, or using a default. There
3480 is one case, however, when no message is output - after "drop". In that case,
3481 the ACL that obeyed "drop" has already supplied the custom message, and NULL is
3482 passed to this function.
3484 In case things go wrong while processing this function, causing an error that
3485 may re-enter this function, there is a recursion check.
3488 reason What $smtp_notquit_reason will be set to in the ACL;
3489 if NULL, the ACL is not run
3490 code The error code to return as part of the response
3491 defaultrespond The default message if there's no user_msg
3497 smtp_notquit_exit(uschar *reason, uschar *code, uschar *defaultrespond, ...)
3500 uschar *user_msg = NULL;
3501 uschar *log_msg = NULL;
3503 /* Check for recursive call */
3505 if (fl.smtp_exit_function_called)
3507 log_write(0, LOG_PANIC, "smtp_notquit_exit() called more than once (%s)",
3511 fl.smtp_exit_function_called = TRUE;
3513 /* Call the not-QUIT ACL, if there is one, unless no reason is given. */
3515 if (acl_smtp_notquit && reason)
3517 smtp_notquit_reason = reason;
3518 if ((rc = acl_check(ACL_WHERE_NOTQUIT, NULL, acl_smtp_notquit, &user_msg,
3519 &log_msg)) == ERROR)
3520 log_write(0, LOG_MAIN|LOG_PANIC, "ACL for not-QUIT returned ERROR: %s",
3524 /* If the connection was dropped, we certainly are no longer talking TLS */
3525 tls_in.active.sock = -1;
3527 /* Write an SMTP response if we are expected to give one. As the default
3528 responses are all internal, they should be reasonable size. */
3530 if (code && defaultrespond)
3533 smtp_respond(code, 3, TRUE, user_msg);
3539 va_start(ap, defaultrespond);
3540 g = string_vformat(NULL, SVFMT_EXTEND|SVFMT_REBUFFER, CS defaultrespond, ap);
3542 smtp_printf("%s %s\r\n", FALSE, code, string_from_gstring(g));
3551 /*************************************************
3552 * Verify HELO argument *
3553 *************************************************/
3555 /* This function is called if helo_verify_hosts or helo_try_verify_hosts is
3556 matched. It is also called from ACL processing if verify = helo is used and
3557 verification was not previously tried (i.e. helo_try_verify_hosts was not
3558 matched). The result of its processing is to set helo_verified and
3559 helo_verify_failed. These variables should both be FALSE for this function to
3562 Note that EHLO/HELO is legitimately allowed to quote an address literal. Allow
3563 for IPv6 ::ffff: literals.
3566 Returns: TRUE if testing was completed;
3567 FALSE on a temporary failure
3571 smtp_verify_helo(void)
3575 HDEBUG(D_receive) debug_printf("verifying EHLO/HELO argument \"%s\"\n",
3578 if (sender_helo_name == NULL)
3580 HDEBUG(D_receive) debug_printf("no EHLO/HELO command was issued\n");
3583 /* Deal with the case of -bs without an IP address */
3585 else if (sender_host_address == NULL)
3587 HDEBUG(D_receive) debug_printf("no client IP address: assume success\n");
3588 f.helo_verified = TRUE;
3591 /* Deal with the more common case when there is a sending IP address */
3593 else if (sender_helo_name[0] == '[')
3595 f.helo_verified = Ustrncmp(sender_helo_name+1, sender_host_address,
3596 Ustrlen(sender_host_address)) == 0;
3599 if (!f.helo_verified)
3601 if (strncmpic(sender_host_address, US"::ffff:", 7) == 0)
3602 f.helo_verified = Ustrncmp(sender_helo_name + 1,
3603 sender_host_address + 7, Ustrlen(sender_host_address) - 7) == 0;
3608 { if (f.helo_verified) debug_printf("matched host address\n"); }
3611 /* Do a reverse lookup if one hasn't already given a positive or negative
3612 response. If that fails, or the name doesn't match, try checking with a forward
3617 if (sender_host_name == NULL && !host_lookup_failed)
3618 yield = host_name_lookup() != DEFER;
3620 /* If a host name is known, check it and all its aliases. */
3622 if (sender_host_name)
3623 if ((f.helo_verified = strcmpic(sender_host_name, sender_helo_name) == 0))
3625 sender_helo_dnssec = sender_host_dnssec;
3626 HDEBUG(D_receive) debug_printf("matched host name\n");
3630 uschar **aliases = sender_host_aliases;
3632 if ((f.helo_verified = strcmpic(*aliases++, sender_helo_name) == 0))
3634 sender_helo_dnssec = sender_host_dnssec;
3638 HDEBUG(D_receive) if (f.helo_verified)
3639 debug_printf("matched alias %s\n", *(--aliases));
3642 /* Final attempt: try a forward lookup of the helo name */
3644 if (!f.helo_verified)
3648 {.name = sender_helo_name, .address = NULL, .mx = MX_NONE, .next = NULL};
3650 {.request = US"*", .require = US""};
3652 HDEBUG(D_receive) debug_printf("getting IP address for %s\n",
3654 rc = host_find_bydns(&h, NULL, HOST_FIND_BY_A | HOST_FIND_BY_AAAA,
3655 NULL, NULL, NULL, &d, NULL, NULL);
3656 if (rc == HOST_FOUND || rc == HOST_FOUND_LOCAL)
3657 for (host_item * hh = &h; hh; hh = hh->next)
3658 if (Ustrcmp(hh->address, sender_host_address) == 0)
3660 f.helo_verified = TRUE;
3661 if (h.dnssec == DS_YES) sender_helo_dnssec = TRUE;
3663 debug_printf("IP address for %s matches calling address\n"
3664 "Forward DNS security status: %sverified\n",
3665 sender_helo_name, sender_helo_dnssec ? "" : "un");
3671 if (!f.helo_verified) f.helo_verify_failed = TRUE; /* We've tried ... */
3678 /*************************************************
3679 * Send user response message *
3680 *************************************************/
3682 /* This function is passed a default response code and a user message. It calls
3683 smtp_message_code() to check and possibly modify the response code, and then
3684 calls smtp_respond() to transmit the response. I put this into a function
3685 just to avoid a lot of repetition.
3688 code the response code
3689 user_msg the user message
3695 smtp_user_msg(uschar *code, uschar *user_msg)
3698 smtp_message_code(&code, &len, &user_msg, NULL, TRUE);
3699 smtp_respond(code, len, TRUE, user_msg);
3705 smtp_in_auth(auth_instance *au, uschar ** s, uschar ** ss)
3707 const uschar *set_id = NULL;
3710 /* Run the checking code, passing the remainder of the command line as
3711 data. Initials the $auth<n> variables as empty. Initialize $0 empty and set
3712 it as the only set numerical variable. The authenticator may set $auth<n>
3713 and also set other numeric variables. The $auth<n> variables are preferred
3714 nowadays; the numerical variables remain for backwards compatibility.
3716 Afterwards, have a go at expanding the set_id string, even if
3717 authentication failed - for bad passwords it can be useful to log the
3718 userid. On success, require set_id to expand and exist, and put it in
3719 authenticated_id. Save this in permanent store, as the working store gets
3720 reset at HELO, RSET, etc. */
3722 for (int i = 0; i < AUTH_VARS; i++) auth_vars[i] = NULL;
3724 expand_nlength[0] = 0; /* $0 contains nothing */
3726 rc = (au->info->servercode)(au, smtp_cmd_data);
3727 if (au->set_id) set_id = expand_string(au->set_id);
3728 expand_nmax = -1; /* Reset numeric variables */
3729 for (int i = 0; i < AUTH_VARS; i++) auth_vars[i] = NULL; /* Reset $auth<n> */
3731 /* The value of authenticated_id is stored in the spool file and printed in
3732 log lines. It must not contain binary zeros or newline characters. In
3733 normal use, it never will, but when playing around or testing, this error
3734 can (did) happen. To guard against this, ensure that the id contains only
3735 printing characters. */
3737 if (set_id) set_id = string_printing(set_id);
3739 /* For the non-OK cases, set up additional logging data if set_id
3743 set_id = set_id && *set_id
3744 ? string_sprintf(" (set_id=%s)", set_id) : US"";
3746 /* Switch on the result */
3751 if (!au->set_id || set_id) /* Complete success */
3753 if (set_id) authenticated_id = string_copy_perm(set_id, TRUE);
3754 sender_host_authenticated = au->name;
3755 sender_host_auth_pubname = au->public_name;
3756 authentication_failed = FALSE;
3757 authenticated_fail_id = NULL; /* Impossible to already be set? */
3760 (sender_host_address ? protocols : protocols_local)
3761 [pextend + pauthed + (tls_in.active.sock >= 0 ? pcrpted:0)];
3762 *s = *ss = US"235 Authentication succeeded";
3763 authenticated_by = au;
3767 /* Authentication succeeded, but we failed to expand the set_id string.
3768 Treat this as a temporary error. */
3770 auth_defer_msg = expand_string_message;
3774 if (set_id) authenticated_fail_id = string_copy_perm(set_id, TRUE);
3775 *s = string_sprintf("435 Unable to authenticate at present%s",
3776 auth_defer_user_msg);
3777 *ss = string_sprintf("435 Unable to authenticate at present%s: %s",
3778 set_id, auth_defer_msg);
3782 *s = *ss = US"501 Invalid base64 data";
3786 *s = *ss = US"501 Authentication cancelled";
3790 *s = *ss = US"553 Initial data not expected";
3794 if (set_id) authenticated_fail_id = string_copy_perm(set_id, TRUE);
3795 *s = US"535 Incorrect authentication data";
3796 *ss = string_sprintf("535 Incorrect authentication data%s", set_id);
3800 if (set_id) authenticated_fail_id = string_copy_perm(set_id, TRUE);
3801 *s = US"435 Internal error";
3802 *ss = string_sprintf("435 Internal error%s: return %d from authentication "
3803 "check", set_id, rc);
3815 qualify_recipient(uschar ** recipient, uschar * smtp_cmd_data, uschar * tag)
3818 if (f.allow_unqualified_recipient || strcmpic(*recipient, US"postmaster") == 0)
3820 DEBUG(D_receive) debug_printf("unqualified address %s accepted\n",
3822 rd = Ustrlen(recipient) + 1;
3823 *recipient = rewrite_address_qualify(*recipient, TRUE);
3826 smtp_printf("501 %s: recipient address must contain a domain\r\n", FALSE,
3828 log_write(L_smtp_syntax_error,
3829 LOG_MAIN|LOG_REJECT, "unqualified %s rejected: <%s> %s%s",
3830 tag, *recipient, host_and_ident(TRUE), host_lookup_msg);
3838 smtp_quit_handler(uschar ** user_msgp, uschar ** log_msgp)
3841 incomplete_transaction_log(US"QUIT");
3844 int rc = acl_check(ACL_WHERE_QUIT, NULL, acl_smtp_quit, user_msgp, log_msgp);
3846 log_write(0, LOG_MAIN|LOG_PANIC, "ACL for QUIT returned ERROR: %s",
3851 (void) setsockopt(fileno(smtp_out), IPPROTO_TCP, TCP_CORK, US &on, sizeof(on));
3855 smtp_respond(US"221", 3, TRUE, *user_msgp);
3857 smtp_printf("221 %s closing connection\r\n", FALSE, smtp_active_hostname);
3860 tls_close(NULL, TLS_SHUTDOWN_NOWAIT);
3863 log_write(L_smtp_connection, LOG_MAIN, "%s closed by QUIT",
3864 smtp_get_connection_info());
3869 smtp_rset_handler(void)
3872 incomplete_transaction_log(US"RSET");
3873 smtp_printf("250 Reset OK\r\n", FALSE);
3874 cmd_list[CMD_LIST_RSET].is_mail_cmd = FALSE;
3879 /*************************************************
3880 * Initialize for SMTP incoming message *
3881 *************************************************/
3883 /* This function conducts the initial dialogue at the start of an incoming SMTP
3884 message, and builds a list of recipients. However, if the incoming message
3885 is part of a batch (-bS option) a separate function is called since it would
3886 be messy having tests splattered about all over this function. This function
3887 therefore handles the case where interaction is occurring. The input and output
3888 files are set up in smtp_in and smtp_out.
3890 The global recipients_list is set to point to a vector of recipient_item
3891 blocks, whose number is given by recipients_count. This is extended by the
3892 receive_add_recipient() function. The global variable sender_address is set to
3893 the sender's address. The yield is +1 if a message has been successfully
3894 started, 0 if a QUIT command was encountered or the connection was refused from
3895 the particular host, or -1 if the connection was lost.
3899 Returns: > 0 message successfully started (reached DATA)
3900 = 0 QUIT read or end of file reached or call refused
3905 smtp_setup_msg(void)
3908 BOOL toomany = FALSE;
3909 BOOL discarded = FALSE;
3910 BOOL last_was_rej_mail = FALSE;
3911 BOOL last_was_rcpt = FALSE;
3912 rmark reset_point = store_mark();
3914 DEBUG(D_receive) debug_printf("smtp_setup_msg entered\n");
3916 /* Reset for start of new message. We allow one RSET not to be counted as a
3917 nonmail command, for those MTAs that insist on sending it between every
3918 message. Ditto for EHLO/HELO and for STARTTLS, to allow for going in and out of
3919 TLS between messages (an Exim client may do this if it has messages queued up
3920 for the host). Note: we do NOT reset AUTH at this point. */
3922 reset_point = smtp_reset(reset_point);
3923 message_ended = END_NOTSTARTED;
3925 chunking_state = f.chunking_offered ? CHUNKING_OFFERED : CHUNKING_NOT_OFFERED;
3927 cmd_list[CMD_LIST_RSET].is_mail_cmd = TRUE;
3928 cmd_list[CMD_LIST_HELO].is_mail_cmd = TRUE;
3929 cmd_list[CMD_LIST_EHLO].is_mail_cmd = TRUE;
3931 cmd_list[CMD_LIST_STARTTLS].is_mail_cmd = TRUE;
3934 /* Set the local signal handler for SIGTERM - it tries to end off tidily */
3936 had_command_sigterm = 0;
3937 os_non_restarting_signal(SIGTERM, command_sigterm_handler);
3939 /* Batched SMTP is handled in a different function. */
3941 if (smtp_batched_input) return smtp_setup_batch_msg();
3943 /* Deal with SMTP commands. This loop is exited by setting done to a POSITIVE
3944 value. The values are 2 larger than the required yield of the function. */
3948 const uschar **argv;
3949 uschar *etrn_command;
3950 uschar *etrn_serialize_key;
3952 uschar *log_msg, *smtp_code;
3953 uschar *user_msg = NULL;
3954 uschar *recipient = NULL;
3955 uschar *hello = NULL;
3957 BOOL was_rej_mail = FALSE;
3958 BOOL was_rcpt = FALSE;
3959 void (*oldsignal)(int);
3961 int start, end, sender_domain, recipient_domain;
3964 uschar *orcpt = NULL;
3969 /* Check once per STARTTLS or SSL-on-connect for a TLS AUTH */
3970 if ( tls_in.active.sock >= 0
3972 && tls_in.certificate_verified
3973 && cmd_list[CMD_LIST_TLS_AUTH].is_mail_cmd
3976 cmd_list[CMD_LIST_TLS_AUTH].is_mail_cmd = FALSE;
3978 for (auth_instance * au = auths; au; au = au->next)
3979 if (strcmpic(US"tls", au->driver_name) == 0)
3982 && (rc = acl_check(ACL_WHERE_AUTH, NULL, acl_smtp_auth,
3983 &user_msg, &log_msg)) != OK
3985 done = smtp_handle_acl_fail(ACL_WHERE_AUTH, rc, user_msg, log_msg);
3988 smtp_cmd_data = NULL;
3990 if (smtp_in_auth(au, &s, &ss) == OK)
3991 { DEBUG(D_auth) debug_printf("tls auth succeeded\n"); }
3993 { DEBUG(D_auth) debug_printf("tls auth not succeeded\n"); }
4001 if (smtp_in) /* Avoid pure-ACKs while in cmd pingpong phase */
4002 (void) setsockopt(fileno(smtp_in), IPPROTO_TCP, TCP_QUICKACK,
4003 US &off, sizeof(off));
4006 switch(smtp_read_command(
4007 #ifndef DISABLE_PIPE_CONNECT
4008 !fl.pipe_connect_acceptable,
4012 GETC_BUFFER_UNLIMITED))
4014 /* The AUTH command is not permitted to occur inside a transaction, and may
4015 occur successfully only once per connection. Actually, that isn't quite
4016 true. When TLS is started, all previous information about a connection must
4017 be discarded, so a new AUTH is permitted at that time.
4019 AUTH may only be used when it has been advertised. However, it seems that
4020 there are clients that send AUTH when it hasn't been advertised, some of
4021 them even doing this after HELO. And there are MTAs that accept this. Sigh.
4022 So there's a get-out that allows this to happen.
4024 AUTH is initially labelled as a "nonmail command" so that one occurrence
4025 doesn't get counted. We change the label here so that multiple failing
4026 AUTHS will eventually hit the nonmail threshold. */
4030 authentication_failed = TRUE;
4031 cmd_list[CMD_LIST_AUTH].is_mail_cmd = FALSE;
4033 if (!fl.auth_advertised && !f.allow_auth_unadvertised)
4035 done = synprot_error(L_smtp_protocol_error, 503, NULL,
4036 US"AUTH command used when not advertised");
4039 if (sender_host_authenticated)
4041 done = synprot_error(L_smtp_protocol_error, 503, NULL,
4042 US"already authenticated");
4047 done = synprot_error(L_smtp_protocol_error, 503, NULL,
4048 US"not permitted in mail transaction");
4055 && (rc = acl_check(ACL_WHERE_AUTH, NULL, acl_smtp_auth,
4056 &user_msg, &log_msg)) != OK
4059 done = smtp_handle_acl_fail(ACL_WHERE_AUTH, rc, user_msg, log_msg);
4063 /* Find the name of the requested authentication mechanism. */
4066 while ((c = *smtp_cmd_data) != 0 && !isspace(c))
4068 if (!isalnum(c) && c != '-' && c != '_')
4070 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4071 US"invalid character in authentication mechanism name");
4077 /* If not at the end of the line, we must be at white space. Terminate the
4078 name and move the pointer on to any data that may be present. */
4080 if (*smtp_cmd_data != 0)
4082 *smtp_cmd_data++ = 0;
4083 while (isspace(*smtp_cmd_data)) smtp_cmd_data++;
4086 /* Search for an authentication mechanism which is configured for use
4087 as a server and which has been advertised (unless, sigh, allow_auth_
4088 unadvertised is set). */
4092 for (au = auths; au; au = au->next)
4093 if (strcmpic(s, au->public_name) == 0 && au->server &&
4094 (au->advertised || f.allow_auth_unadvertised))
4099 c = smtp_in_auth(au, &s, &ss);
4101 smtp_printf("%s\r\n", FALSE, s);
4103 log_write(0, LOG_MAIN|LOG_REJECT, "%s authenticator failed for %s: %s",
4104 au->name, host_and_ident(FALSE), ss);
4107 done = synprot_error(L_smtp_protocol_error, 504, NULL,
4108 string_sprintf("%s authentication mechanism not supported", s));
4111 break; /* AUTH_CMD */
4113 /* The HELO/EHLO commands are permitted to appear in the middle of a
4114 session as well as at the beginning. They have the effect of a reset in
4115 addition to their other functions. Their absence at the start cannot be
4116 taken to be an error.
4120 If the EHLO command is not acceptable to the SMTP server, 501, 500,
4121 or 502 failure replies MUST be returned as appropriate. The SMTP
4122 server MUST stay in the same state after transmitting these replies
4123 that it was in before the EHLO was received.
4125 Therefore, we do not do the reset until after checking the command for
4126 acceptability. This change was made for Exim release 4.11. Previously
4127 it did the reset first. */
4140 HELO_EHLO: /* Common code for HELO and EHLO */
4141 cmd_list[CMD_LIST_HELO].is_mail_cmd = FALSE;
4142 cmd_list[CMD_LIST_EHLO].is_mail_cmd = FALSE;
4144 /* Reject the HELO if its argument was invalid or non-existent. A
4145 successful check causes the argument to be saved in malloc store. */
4147 if (!check_helo(smtp_cmd_data))
4149 smtp_printf("501 Syntactically invalid %s argument(s)\r\n", FALSE, hello);
4151 log_write(0, LOG_MAIN|LOG_REJECT, "rejected %s from %s: syntactically "
4152 "invalid argument(s): %s", hello, host_and_ident(FALSE),
4153 *smtp_cmd_argument == 0 ? US"(no argument given)" :
4154 string_printing(smtp_cmd_argument));
4156 if (++synprot_error_count > smtp_max_synprot_errors)
4158 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
4159 "syntax or protocol errors (last command was \"%s\")",
4160 host_and_ident(FALSE), string_printing(smtp_cmd_buffer));
4167 /* If sender_host_unknown is true, we have got here via the -bs interface,
4168 not called from inetd. Otherwise, we are running an IP connection and the
4169 host address will be set. If the helo name is the primary name of this
4170 host and we haven't done a reverse lookup, force one now. If helo_required
4171 is set, ensure that the HELO name matches the actual host. If helo_verify
4172 is set, do the same check, but softly. */
4174 if (!f.sender_host_unknown)
4176 BOOL old_helo_verified = f.helo_verified;
4177 uschar *p = smtp_cmd_data;
4179 while (*p != 0 && !isspace(*p)) { *p = tolower(*p); p++; }
4182 /* Force a reverse lookup if HELO quoted something in helo_lookup_domains
4183 because otherwise the log can be confusing. */
4185 if ( !sender_host_name
4186 && match_isinlist(sender_helo_name, CUSS &helo_lookup_domains, 0,
4187 &domainlist_anchor, NULL, MCL_DOMAIN, TRUE, NULL) == OK)
4188 (void)host_name_lookup();
4190 /* Rebuild the fullhost info to include the HELO name (and the real name
4191 if it was looked up.) */
4193 host_build_sender_fullhost(); /* Rebuild */
4194 set_process_info("handling%s incoming connection from %s",
4195 tls_in.active.sock >= 0 ? " TLS" : "", host_and_ident(FALSE));
4197 /* Verify if configured. This doesn't give much security, but it does
4198 make some people happy to be able to do it. If helo_required is set,
4199 (host matches helo_verify_hosts) failure forces rejection. If helo_verify
4200 is set (host matches helo_try_verify_hosts), it does not. This is perhaps
4201 now obsolescent, since the verification can now be requested selectively
4204 f.helo_verified = f.helo_verify_failed = sender_helo_dnssec = FALSE;
4205 if (fl.helo_required || fl.helo_verify)
4207 BOOL tempfail = !smtp_verify_helo();
4208 if (!f.helo_verified)
4210 if (fl.helo_required)
4212 smtp_printf("%d %s argument does not match calling host\r\n", FALSE,
4213 tempfail? 451 : 550, hello);
4214 log_write(0, LOG_MAIN|LOG_REJECT, "%srejected \"%s %s\" from %s",
4215 tempfail? "temporarily " : "",
4216 hello, sender_helo_name, host_and_ident(FALSE));
4217 f.helo_verified = old_helo_verified;
4218 break; /* End of HELO/EHLO processing */
4220 HDEBUG(D_all) debug_printf("%s verification failed but host is in "
4221 "helo_try_verify_hosts\n", hello);
4227 /* set up SPF context */
4228 spf_conn_init(sender_helo_name, sender_host_address);
4231 /* Apply an ACL check if one is defined; afterwards, recheck
4232 synchronization in case the client started sending in a delay. */
4235 if ((rc = acl_check(ACL_WHERE_HELO, NULL, acl_smtp_helo,
4236 &user_msg, &log_msg)) != OK)
4238 done = smtp_handle_acl_fail(ACL_WHERE_HELO, rc, user_msg, log_msg);
4239 sender_helo_name = NULL;
4240 host_build_sender_fullhost(); /* Rebuild */
4243 #ifndef DISABLE_PIPE_CONNECT
4244 else if (!fl.pipe_connect_acceptable && !check_sync())
4246 else if (!check_sync())
4250 /* Generate an OK reply. The default string includes the ident if present,
4251 and also the IP address if present. Reflecting back the ident is intended
4252 as a deterrent to mail forgers. For maximum efficiency, and also because
4253 some broken systems expect each response to be in a single packet, arrange
4254 that the entire reply is sent in one write(). */
4256 fl.auth_advertised = FALSE;
4257 f.smtp_in_pipelining_advertised = FALSE;
4259 fl.tls_advertised = FALSE;
4261 fl.dsn_advertised = FALSE;
4263 fl.smtputf8_advertised = FALSE;
4266 smtp_code = US"250 "; /* Default response code plus space*/
4269 /* sender_host_name below will be tainted, so save on copy when we hit it */
4270 g = string_get_tainted(24, TRUE);
4271 g = string_fmt_append(g, "%.3s %s Hello %s%s%s",
4273 smtp_active_hostname,
4274 sender_ident ? sender_ident : US"",
4275 sender_ident ? US" at " : US"",
4276 sender_host_name ? sender_host_name : sender_helo_name);
4278 if (sender_host_address)
4279 g = string_fmt_append(g, " [%s]", sender_host_address);
4282 /* A user-supplied EHLO greeting may not contain more than one line. Note
4283 that the code returned by smtp_message_code() includes the terminating
4284 whitespace character. */
4290 smtp_message_code(&smtp_code, &codelen, &user_msg, NULL, TRUE);
4291 s = string_sprintf("%.*s%s", codelen, smtp_code, user_msg);
4292 if ((ss = strpbrk(CS s, "\r\n")) != NULL)
4294 log_write(0, LOG_MAIN|LOG_PANIC, "EHLO/HELO response must not contain "
4295 "newlines: message truncated: %s", string_printing(s));
4298 g = string_cat(NULL, s);
4301 g = string_catn(g, US"\r\n", 2);
4303 /* If we received EHLO, we must create a multiline response which includes
4304 the functions supported. */
4310 /* I'm not entirely happy with this, as an MTA is supposed to check
4311 that it has enough room to accept a message of maximum size before
4312 it sends this. However, there seems little point in not sending it.
4313 The actual size check happens later at MAIL FROM time. By postponing it
4314 till then, VRFY and EXPN can be used after EHLO when space is short. */
4316 if (thismessage_size_limit > 0)
4317 g = string_fmt_append(g, "%.3s-SIZE %d\r\n", smtp_code,
4318 thismessage_size_limit);
4321 g = string_catn(g, smtp_code, 3);
4322 g = string_catn(g, US"-SIZE\r\n", 7);
4325 /* Exim does not do protocol conversion or data conversion. It is 8-bit
4326 clean; if it has an 8-bit character in its hand, it just sends it. It
4327 cannot therefore specify 8BITMIME and remain consistent with the RFCs.
4328 However, some users want this option simply in order to stop MUAs
4329 mangling messages that contain top-bit-set characters. It is therefore
4330 provided as an option. */
4332 if (accept_8bitmime)
4334 g = string_catn(g, smtp_code, 3);
4335 g = string_catn(g, US"-8BITMIME\r\n", 11);
4338 /* Advertise DSN support if configured to do so. */
4339 if (verify_check_host(&dsn_advertise_hosts) != FAIL)
4341 g = string_catn(g, smtp_code, 3);
4342 g = string_catn(g, US"-DSN\r\n", 6);
4343 fl.dsn_advertised = TRUE;
4346 /* Advertise ETRN/VRFY/EXPN if there's are ACL checking whether a host is
4347 permitted to issue them; a check is made when any host actually tries. */
4351 g = string_catn(g, smtp_code, 3);
4352 g = string_catn(g, US"-ETRN\r\n", 7);
4356 g = string_catn(g, smtp_code, 3);
4357 g = string_catn(g, US"-VRFY\r\n", 7);
4361 g = string_catn(g, smtp_code, 3);
4362 g = string_catn(g, US"-EXPN\r\n", 7);
4365 /* Exim is quite happy with pipelining, so let the other end know that
4366 it is safe to use it, unless advertising is disabled. */
4368 if ( f.pipelining_enable
4369 && verify_check_host(&pipelining_advertise_hosts) == OK)
4371 g = string_catn(g, smtp_code, 3);
4372 g = string_catn(g, US"-PIPELINING\r\n", 13);
4373 sync_cmd_limit = NON_SYNC_CMD_PIPELINING;
4374 f.smtp_in_pipelining_advertised = TRUE;
4376 #ifndef DISABLE_PIPE_CONNECT
4377 if (fl.pipe_connect_acceptable)
4379 f.smtp_in_early_pipe_advertised = TRUE;
4380 g = string_catn(g, smtp_code, 3);
4381 g = string_catn(g, US"-" EARLY_PIPE_FEATURE_NAME "\r\n", EARLY_PIPE_FEATURE_LEN+3);
4387 /* If any server authentication mechanisms are configured, advertise
4388 them if the current host is in auth_advertise_hosts. The problem with
4389 advertising always is that some clients then require users to
4390 authenticate (and aren't configurable otherwise) even though it may not
4391 be necessary (e.g. if the host is in host_accept_relay).
4393 RFC 2222 states that SASL mechanism names contain only upper case
4394 letters, so output the names in upper case, though we actually recognize
4395 them in either case in the AUTH command. */
4399 && !sender_host_authenticated
4401 && verify_check_host(&auth_advertise_hosts) == OK
4405 for (auth_instance * au = auths; au; au = au->next)
4407 au->advertised = FALSE;
4410 DEBUG(D_auth+D_expand) debug_printf_indent(
4411 "Evaluating advertise_condition for %s %s athenticator\n",
4412 au->name, au->public_name);
4413 if ( !au->advertise_condition
4414 || expand_check_condition(au->advertise_condition, au->name,
4421 g = string_catn(g, smtp_code, 3);
4422 g = string_catn(g, US"-AUTH", 5);
4424 fl.auth_advertised = TRUE;
4427 g = string_catn(g, US" ", 1);
4428 g = string_cat (g, au->public_name);
4429 while (++saveptr < g->ptr) g->s[saveptr] = toupper(g->s[saveptr]);
4430 au->advertised = TRUE;
4435 if (!first) g = string_catn(g, US"\r\n", 2);
4438 /* RFC 3030 CHUNKING */
4440 if (verify_check_host(&chunking_advertise_hosts) != FAIL)
4442 g = string_catn(g, smtp_code, 3);
4443 g = string_catn(g, US"-CHUNKING\r\n", 11);
4444 f.chunking_offered = TRUE;
4445 chunking_state = CHUNKING_OFFERED;
4448 /* Advertise TLS (Transport Level Security) aka SSL (Secure Socket Layer)
4449 if it has been included in the binary, and the host matches
4450 tls_advertise_hosts. We must *not* advertise if we are already in a
4451 secure connection. */
4454 if (tls_in.active.sock < 0 &&
4455 verify_check_host(&tls_advertise_hosts) != FAIL)
4457 g = string_catn(g, smtp_code, 3);
4458 g = string_catn(g, US"-STARTTLS\r\n", 11);
4459 fl.tls_advertised = TRUE;
4463 #ifndef DISABLE_PRDR
4464 /* Per Recipient Data Response, draft by Eric A. Hall extending RFC */
4467 g = string_catn(g, smtp_code, 3);
4468 g = string_catn(g, US"-PRDR\r\n", 7);
4473 if ( accept_8bitmime
4474 && verify_check_host(&smtputf8_advertise_hosts) != FAIL)
4476 g = string_catn(g, smtp_code, 3);
4477 g = string_catn(g, US"-SMTPUTF8\r\n", 11);
4478 fl.smtputf8_advertised = TRUE;
4482 /* Finish off the multiline reply with one that is always available. */
4484 g = string_catn(g, smtp_code, 3);
4485 g = string_catn(g, US" HELP\r\n", 7);
4488 /* Terminate the string (for debug), write it, and note that HELO/EHLO
4492 if (tls_in.active.sock >= 0)
4493 (void)tls_write(NULL, g->s, g->ptr,
4494 # ifndef DISABLE_PIPE_CONNECT
4495 fl.pipe_connect_acceptable && pipeline_connect_sends());
4503 int i = fwrite(g->s, 1, g->ptr, smtp_out); i = i; /* compiler quietening */
4509 (void) string_from_gstring(g);
4510 while ((cr = Ustrchr(g->s, '\r')) != NULL) /* lose CRs */
4511 memmove(cr, cr + 1, (g->ptr--) - (cr - g->s));
4512 debug_printf("SMTP>> %s", g->s);
4514 fl.helo_seen = TRUE;
4516 /* Reset the protocol and the state, abandoning any previous message. */
4518 (sender_host_address ? protocols : protocols_local)
4520 ? pextend + (sender_host_authenticated ? pauthed : 0)
4522 + (tls_in.active.sock >= 0 ? pcrpted : 0)
4524 cancel_cutthrough_connection(TRUE, US"sent EHLO response");
4525 reset_point = smtp_reset(reset_point);
4527 break; /* HELO/EHLO */
4530 /* The MAIL command requires an address as an operand. All we do
4531 here is to parse it for syntactic correctness. The form "<>" is
4532 a special case which converts into an empty string. The start/end
4533 pointers in the original are not used further for this address, as
4534 it is the canonical extracted address which is all that is kept. */
4538 smtp_mailcmd_count++; /* Count for limit and ratelimit */
4539 was_rej_mail = TRUE; /* Reset if accepted */
4540 env_mail_type_t * mail_args; /* Sanity check & validate args */
4542 if (fl.helo_required && !fl.helo_seen)
4544 smtp_printf("503 HELO or EHLO required\r\n", FALSE);
4545 log_write(0, LOG_MAIN|LOG_REJECT, "rejected MAIL from %s: no "
4546 "HELO/EHLO given", host_and_ident(FALSE));
4552 done = synprot_error(L_smtp_protocol_error, 503, NULL,
4553 US"sender already given");
4557 if (!*smtp_cmd_data)
4559 done = synprot_error(L_smtp_protocol_error, 501, NULL,
4560 US"MAIL must have an address operand");
4564 /* Check to see if the limit for messages per connection would be
4565 exceeded by accepting further messages. */
4567 if (smtp_accept_max_per_connection > 0 &&
4568 smtp_mailcmd_count > smtp_accept_max_per_connection)
4570 smtp_printf("421 too many messages in this connection\r\n", FALSE);
4571 log_write(0, LOG_MAIN|LOG_REJECT, "rejected MAIL command %s: too many "
4572 "messages in one connection", host_and_ident(TRUE));
4576 /* Reset for start of message - even if this is going to fail, we
4577 obviously need to throw away any previous data. */
4579 cancel_cutthrough_connection(TRUE, US"MAIL received");
4580 reset_point = smtp_reset(reset_point);
4582 sender_data = recipient_data = NULL;
4584 /* Loop, checking for ESMTP additions to the MAIL FROM command. */
4586 if (fl.esmtp) for(;;)
4588 uschar *name, *value, *end;
4589 unsigned long int size;
4590 BOOL arg_error = FALSE;
4592 if (!extract_option(&name, &value)) break;
4594 for (mail_args = env_mail_type_list;
4595 mail_args->value != ENV_MAIL_OPT_NULL;
4598 if (strcmpic(name, mail_args->name) == 0)
4600 if (mail_args->need_value && strcmpic(value, US"") == 0)
4603 switch(mail_args->value)
4605 /* Handle SIZE= by reading the value. We don't do the check till later,
4606 in order to be able to log the sender address on failure. */
4607 case ENV_MAIL_OPT_SIZE:
4608 if (((size = Ustrtoul(value, &end, 10)), *end == 0))
4610 if ((size == ULONG_MAX && errno == ERANGE) || size > INT_MAX)
4612 message_size = (int)size;
4618 /* If this session was initiated with EHLO and accept_8bitmime is set,
4619 Exim will have indicated that it supports the BODY=8BITMIME option. In
4620 fact, it does not support this according to the RFCs, in that it does not
4621 take any special action for forwarding messages containing 8-bit
4622 characters. That is why accept_8bitmime is not the default setting, but
4623 some sites want the action that is provided. We recognize both "8BITMIME"
4624 and "7BIT" as body types, but take no action. */
4625 case ENV_MAIL_OPT_BODY:
4626 if (accept_8bitmime) {
4627 if (strcmpic(value, US"8BITMIME") == 0)
4629 else if (strcmpic(value, US"7BIT") == 0)
4634 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4635 US"invalid data for BODY");
4638 DEBUG(D_receive) debug_printf("8BITMIME: %d\n", body_8bitmime);
4644 /* Handle the two DSN options, but only if configured to do so (which
4645 will have caused "DSN" to be given in the EHLO response). The code itself
4646 is included only if configured in at build time. */
4648 case ENV_MAIL_OPT_RET:
4649 if (fl.dsn_advertised)
4651 /* Check if RET has already been set */
4654 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4655 US"RET can be specified once only");
4658 dsn_ret = strcmpic(value, US"HDRS") == 0
4660 : strcmpic(value, US"FULL") == 0
4663 DEBUG(D_receive) debug_printf("DSN_RET: %d\n", dsn_ret);
4664 /* Check for invalid invalid value, and exit with error */
4667 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4668 US"Value for RET is invalid");
4673 case ENV_MAIL_OPT_ENVID:
4674 if (fl.dsn_advertised)
4676 /* Check if the dsn envid has been already set */
4679 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4680 US"ENVID can be specified once only");
4683 dsn_envid = string_copy(value);
4684 DEBUG(D_receive) debug_printf("DSN_ENVID: %s\n", dsn_envid);
4688 /* Handle the AUTH extension. If the value given is not "<>" and either
4689 the ACL says "yes" or there is no ACL but the sending host is
4690 authenticated, we set it up as the authenticated sender. However, if the
4691 authenticator set a condition to be tested, we ignore AUTH on MAIL unless
4692 the condition is met. The value of AUTH is an xtext, which means that +,
4693 = and cntrl chars are coded in hex; however "<>" is unaffected by this
4695 case ENV_MAIL_OPT_AUTH:
4696 if (Ustrcmp(value, "<>") != 0)
4701 if (auth_xtextdecode(value, &authenticated_sender) < 0)
4703 /* Put back terminator overrides for error message */
4706 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4707 US"invalid data for AUTH");
4710 if (!acl_smtp_mailauth)
4712 ignore_msg = US"client not authenticated";
4713 rc = sender_host_authenticated ? OK : FAIL;
4717 ignore_msg = US"rejected by ACL";
4718 rc = acl_check(ACL_WHERE_MAILAUTH, NULL, acl_smtp_mailauth,
4719 &user_msg, &log_msg);
4725 if (authenticated_by == NULL ||
4726 authenticated_by->mail_auth_condition == NULL ||
4727 expand_check_condition(authenticated_by->mail_auth_condition,
4728 authenticated_by->name, US"authenticator"))
4729 break; /* Accept the AUTH */
4731 ignore_msg = US"server_mail_auth_condition failed";
4732 if (authenticated_id != NULL)
4733 ignore_msg = string_sprintf("%s: authenticated ID=\"%s\"",
4734 ignore_msg, authenticated_id);
4739 authenticated_sender = NULL;
4740 log_write(0, LOG_MAIN, "ignoring AUTH=%s from %s (%s)",
4741 value, host_and_ident(TRUE), ignore_msg);
4744 /* Should only get DEFER or ERROR here. Put back terminator
4745 overrides for error message */
4750 (void)smtp_handle_acl_fail(ACL_WHERE_MAILAUTH, rc, user_msg,
4757 #ifndef DISABLE_PRDR
4758 case ENV_MAIL_OPT_PRDR:
4760 prdr_requested = TRUE;
4765 case ENV_MAIL_OPT_UTF8:
4766 if (!fl.smtputf8_advertised)
4768 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4769 US"SMTPUTF8 used when not advertised");
4773 DEBUG(D_receive) debug_printf("smtputf8 requested\n");
4774 message_smtputf8 = allow_utf8_domains = TRUE;
4775 if (Ustrncmp(received_protocol, US"utf8", 4) != 0)
4777 int old_pool = store_pool;
4778 store_pool = POOL_PERM;
4779 received_protocol = string_sprintf("utf8%s", received_protocol);
4780 store_pool = old_pool;
4785 /* No valid option. Stick back the terminator characters and break
4786 the loop. Do the name-terminator second as extract_option sets
4787 value==name when it found no equal-sign.
4788 An error for a malformed address will occur. */
4789 case ENV_MAIL_OPT_NULL:
4797 /* Break out of for loop if switch() had bad argument or
4798 when start of the email address is reached */
4799 if (arg_error) break;
4802 /* If we have passed the threshold for rate limiting, apply the current
4803 delay, and update it for next time, provided this is a limited host. */
4805 if (smtp_mailcmd_count > smtp_rlm_threshold &&
4806 verify_check_host(&smtp_ratelimit_hosts) == OK)
4808 DEBUG(D_receive) debug_printf("rate limit MAIL: delay %.3g sec\n",
4809 smtp_delay_mail/1000.0);
4810 millisleep((int)smtp_delay_mail);
4811 smtp_delay_mail *= smtp_rlm_factor;
4812 if (smtp_delay_mail > (double)smtp_rlm_limit)
4813 smtp_delay_mail = (double)smtp_rlm_limit;
4816 /* Now extract the address, first applying any SMTP-time rewriting. The
4817 TRUE flag allows "<>" as a sender address. */
4819 raw_sender = rewrite_existflags & rewrite_smtp
4820 ? rewrite_one(smtp_cmd_data, rewrite_smtp, NULL, FALSE, US"",
4821 global_rewrite_rules)
4825 parse_extract_address(raw_sender, &errmess, &start, &end, &sender_domain,
4830 done = synprot_error(L_smtp_syntax_error, 501, smtp_cmd_data, errmess);
4834 sender_address = raw_sender;
4836 /* If there is a configured size limit for mail, check that this message
4837 doesn't exceed it. The check is postponed to this point so that the sender
4840 if (thismessage_size_limit > 0 && message_size > thismessage_size_limit)
4842 smtp_printf("552 Message size exceeds maximum permitted\r\n", FALSE);
4843 log_write(L_size_reject,
4844 LOG_MAIN|LOG_REJECT, "rejected MAIL FROM:<%s> %s: "
4845 "message too big: size%s=%d max=%d",
4847 host_and_ident(TRUE),
4848 (message_size == INT_MAX)? ">" : "",
4850 thismessage_size_limit);
4851 sender_address = NULL;
4855 /* Check there is enough space on the disk unless configured not to.
4856 When smtp_check_spool_space is set, the check is for thismessage_size_limit
4857 plus the current message - i.e. we accept the message only if it won't
4858 reduce the space below the threshold. Add 5000 to the size to allow for
4859 overheads such as the Received: line and storing of recipients, etc.
4860 By putting the check here, even when SIZE is not given, it allow VRFY
4861 and EXPN etc. to be used when space is short. */
4863 if (!receive_check_fs(
4864 (smtp_check_spool_space && message_size >= 0)?
4865 message_size + 5000 : 0))
4867 smtp_printf("452 Space shortage, please try later\r\n", FALSE);
4868 sender_address = NULL;
4872 /* If sender_address is unqualified, reject it, unless this is a locally
4873 generated message, or the sending host or net is permitted to send
4874 unqualified addresses - typically local machines behaving as MUAs -
4875 in which case just qualify the address. The flag is set above at the start
4876 of the SMTP connection. */
4878 if (!sender_domain && *sender_address)
4879 if (f.allow_unqualified_sender)
4881 sender_domain = Ustrlen(sender_address) + 1;
4882 sender_address = rewrite_address_qualify(sender_address, FALSE);
4883 DEBUG(D_receive) debug_printf("unqualified address %s accepted\n",
4888 smtp_printf("501 %s: sender address must contain a domain\r\n", FALSE,
4890 log_write(L_smtp_syntax_error,
4891 LOG_MAIN|LOG_REJECT,
4892 "unqualified sender rejected: <%s> %s%s",
4894 host_and_ident(TRUE),
4896 sender_address = NULL;
4900 /* Apply an ACL check if one is defined, before responding. Afterwards,
4901 when pipelining is not advertised, do another sync check in case the ACL
4902 delayed and the client started sending in the meantime. */
4906 rc = acl_check(ACL_WHERE_MAIL, NULL, acl_smtp_mail, &user_msg, &log_msg);
4907 if (rc == OK && !f.smtp_in_pipelining_advertised && !check_sync())
4913 if (rc == OK || rc == DISCARD)
4915 BOOL more = pipeline_response();
4918 smtp_printf("%s%s%s", more, US"250 OK",
4919 #ifndef DISABLE_PRDR
4920 prdr_requested ? US", PRDR Requested" : US"",
4927 #ifndef DISABLE_PRDR
4929 user_msg = string_sprintf("%s%s", user_msg, US", PRDR Requested");
4931 smtp_user_msg(US"250", user_msg);
4933 smtp_delay_rcpt = smtp_rlr_base;
4934 f.recipients_discarded = (rc == DISCARD);
4935 was_rej_mail = FALSE;
4939 done = smtp_handle_acl_fail(ACL_WHERE_MAIL, rc, user_msg, log_msg);
4940 sender_address = NULL;
4945 /* The RCPT command requires an address as an operand. There may be any
4946 number of RCPT commands, specifying multiple recipients. We build them all
4947 into a data structure. The start/end values given by parse_extract_address
4948 are not used, as we keep only the extracted address. */
4953 was_rcpt = fl.rcpt_in_progress = TRUE;
4955 /* There must be a sender address; if the sender was rejected and
4956 pipelining was advertised, we assume the client was pipelining, and do not
4957 count this as a protocol error. Reset was_rej_mail so that further RCPTs
4958 get the same treatment. */
4960 if (sender_address == NULL)
4962 if (f.smtp_in_pipelining_advertised && last_was_rej_mail)
4964 smtp_printf("503 sender not yet given\r\n", FALSE);
4965 was_rej_mail = TRUE;
4969 done = synprot_error(L_smtp_protocol_error, 503, NULL,
4970 US"sender not yet given");
4971 was_rcpt = FALSE; /* Not a valid RCPT */
4977 /* Check for an operand */
4979 if (smtp_cmd_data[0] == 0)
4981 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4982 US"RCPT must have an address operand");
4987 /* Set the DSN flags orcpt and dsn_flags from the session*/
4991 if (fl.esmtp) for(;;)
4993 uschar *name, *value;
4995 if (!extract_option(&name, &value))
4998 if (fl.dsn_advertised && strcmpic(name, US"ORCPT") == 0)
5000 /* Check whether orcpt has been already set */
5003 done = synprot_error(L_smtp_syntax_error, 501, NULL,
5004 US"ORCPT can be specified once only");
5007 orcpt = string_copy(value);
5008 DEBUG(D_receive) debug_printf("DSN orcpt: %s\n", orcpt);
5011 else if (fl.dsn_advertised && strcmpic(name, US"NOTIFY") == 0)
5013 /* Check if the notify flags have been already set */
5016 done = synprot_error(L_smtp_syntax_error, 501, NULL,
5017 US"NOTIFY can be specified once only");
5020 if (strcmpic(value, US"NEVER") == 0)
5021 dsn_flags |= rf_notify_never;
5028 while (*pp != 0 && *pp != ',') pp++;
5029 if (*pp == ',') *pp++ = 0;
5030 if (strcmpic(p, US"SUCCESS") == 0)
5032 DEBUG(D_receive) debug_printf("DSN: Setting notify success\n");
5033 dsn_flags |= rf_notify_success;
5035 else if (strcmpic(p, US"FAILURE") == 0)
5037 DEBUG(D_receive) debug_printf("DSN: Setting notify failure\n");
5038 dsn_flags |= rf_notify_failure;
5040 else if (strcmpic(p, US"DELAY") == 0)
5042 DEBUG(D_receive) debug_printf("DSN: Setting notify delay\n");
5043 dsn_flags |= rf_notify_delay;
5047 /* Catch any strange values */
5048 done = synprot_error(L_smtp_syntax_error, 501, NULL,
5049 US"Invalid value for NOTIFY parameter");
5054 DEBUG(D_receive) debug_printf("DSN Flags: %x\n", dsn_flags);
5058 /* Unknown option. Stick back the terminator characters and break
5059 the loop. An error for a malformed address will occur. */
5063 DEBUG(D_receive) debug_printf("Invalid RCPT option: %s : %s\n", name, value);
5070 /* Apply SMTP rewriting then extract the working address. Don't allow "<>"
5071 as a recipient address */
5073 recipient = rewrite_existflags & rewrite_smtp
5074 ? rewrite_one(smtp_cmd_data, rewrite_smtp, NULL, FALSE, US"",
5075 global_rewrite_rules)
5078 if (!(recipient = parse_extract_address(recipient, &errmess, &start, &end,
5079 &recipient_domain, FALSE)))
5081 done = synprot_error(L_smtp_syntax_error, 501, smtp_cmd_data, errmess);
5086 /* If the recipient address is unqualified, reject it, unless this is a
5087 locally generated message. However, unqualified addresses are permitted
5088 from a configured list of hosts and nets - typically when behaving as
5089 MUAs rather than MTAs. Sad that SMTP is used for both types of traffic,
5090 really. The flag is set at the start of the SMTP connection.
5092 RFC 1123 talks about supporting "the reserved mailbox postmaster"; I always
5093 assumed this meant "reserved local part", but the revision of RFC 821 and
5094 friends now makes it absolutely clear that it means *mailbox*. Consequently
5095 we must always qualify this address, regardless. */
5097 if (!recipient_domain)
5098 if (!(recipient_domain = qualify_recipient(&recipient, smtp_cmd_data,
5105 /* Check maximum allowed */
5107 if (rcpt_count > recipients_max && recipients_max > 0)
5109 if (recipients_max_reject)
5112 smtp_printf("552 too many recipients\r\n", FALSE);
5114 log_write(0, LOG_MAIN|LOG_REJECT, "too many recipients: message "
5115 "rejected: sender=<%s> %s", sender_address, host_and_ident(TRUE));
5120 smtp_printf("452 too many recipients\r\n", FALSE);
5122 log_write(0, LOG_MAIN|LOG_REJECT, "too many recipients: excess "
5123 "temporarily rejected: sender=<%s> %s", sender_address,
5124 host_and_ident(TRUE));
5131 /* If we have passed the threshold for rate limiting, apply the current
5132 delay, and update it for next time, provided this is a limited host. */
5134 if (rcpt_count > smtp_rlr_threshold &&
5135 verify_check_host(&smtp_ratelimit_hosts) == OK)
5137 DEBUG(D_receive) debug_printf("rate limit RCPT: delay %.3g sec\n",
5138 smtp_delay_rcpt/1000.0);
5139 millisleep((int)smtp_delay_rcpt);
5140 smtp_delay_rcpt *= smtp_rlr_factor;
5141 if (smtp_delay_rcpt > (double)smtp_rlr_limit)
5142 smtp_delay_rcpt = (double)smtp_rlr_limit;
5145 /* If the MAIL ACL discarded all the recipients, we bypass ACL checking
5146 for them. Otherwise, check the access control list for this recipient. As
5147 there may be a delay in this, re-check for a synchronization error
5148 afterwards, unless pipelining was advertised. */
5150 if (f.recipients_discarded)
5153 if ( (rc = acl_check(ACL_WHERE_RCPT, recipient, acl_smtp_rcpt, &user_msg,
5155 && !f.smtp_in_pipelining_advertised && !check_sync())
5158 /* The ACL was happy */
5162 BOOL more = pipeline_response();
5165 smtp_user_msg(US"250", user_msg);
5167 smtp_printf("250 Accepted\r\n", more);
5168 receive_add_recipient(recipient, -1);
5170 /* Set the dsn flags in the recipients_list */
5171 recipients_list[recipients_count-1].orcpt = orcpt;
5172 recipients_list[recipients_count-1].dsn_flags = dsn_flags;
5174 DEBUG(D_receive) debug_printf("DSN: orcpt: %s flags: %d\n",
5175 recipients_list[recipients_count-1].orcpt,
5176 recipients_list[recipients_count-1].dsn_flags);
5179 /* The recipient was discarded */
5181 else if (rc == DISCARD)
5184 smtp_user_msg(US"250", user_msg);
5186 smtp_printf("250 Accepted\r\n", FALSE);
5189 log_write(0, LOG_MAIN|LOG_REJECT, "%s F=<%s> RCPT %s: "
5190 "discarded by %s ACL%s%s", host_and_ident(TRUE),
5191 sender_address_unrewritten? sender_address_unrewritten : sender_address,
5192 smtp_cmd_argument, f.recipients_discarded? "MAIL" : "RCPT",
5193 log_msg ? US": " : US"", log_msg ? log_msg : US"");
5196 /* Either the ACL failed the address, or it was deferred. */
5200 if (rc == FAIL) rcpt_fail_count++; else rcpt_defer_count++;
5201 done = smtp_handle_acl_fail(ACL_WHERE_RCPT, rc, user_msg, log_msg);
5206 /* The DATA command is legal only if it follows successful MAIL FROM
5207 and RCPT TO commands. However, if pipelining is advertised, a bad DATA is
5208 not counted as a protocol error if it follows RCPT (which must have been
5209 rejected if there are no recipients.) This function is complete when a
5210 valid DATA command is encountered.
5212 Note concerning the code used: RFC 2821 says this:
5214 - If there was no MAIL, or no RCPT, command, or all such commands
5215 were rejected, the server MAY return a "command out of sequence"
5216 (503) or "no valid recipients" (554) reply in response to the
5219 The example in the pipelining RFC 2920 uses 554, but I use 503 here
5220 because it is the same whether pipelining is in use or not.
5222 If all the RCPT commands that precede DATA provoked the same error message
5223 (often indicating some kind of system error), it is helpful to include it
5224 with the DATA rejection (an idea suggested by Tony Finch). */
5231 if (chunking_state != CHUNKING_OFFERED)
5233 done = synprot_error(L_smtp_protocol_error, 503, NULL,
5234 US"BDAT command used when CHUNKING not advertised");
5238 /* grab size, endmarker */
5240 if (sscanf(CS smtp_cmd_data, "%u %n", &chunking_datasize, &n) < 1)
5242 done = synprot_error(L_smtp_protocol_error, 501, NULL,
5243 US"missing size for BDAT command");
5246 chunking_state = strcmpic(smtp_cmd_data+n, US"LAST") == 0
5247 ? CHUNKING_LAST : CHUNKING_ACTIVE;
5248 chunking_data_left = chunking_datasize;
5249 DEBUG(D_receive) debug_printf("chunking state %d, %d bytes\n",
5250 (int)chunking_state, chunking_data_left);
5252 /* push the current receive_* function on the "stack", and
5253 replace them by bdat_getc(), which in turn will use the lwr_receive_*
5254 functions to do the dirty work. */
5255 lwr_receive_getc = receive_getc;
5256 lwr_receive_getbuf = receive_getbuf;
5257 lwr_receive_ungetc = receive_ungetc;
5259 receive_getc = bdat_getc;
5260 receive_ungetc = bdat_ungetc;
5271 DATA_BDAT: /* Common code for DATA and BDAT */
5272 #ifndef DISABLE_PIPE_CONNECT
5273 fl.pipe_connect_acceptable = FALSE;
5275 if (!discarded && recipients_count <= 0)
5277 if (fl.rcpt_smtp_response_same && rcpt_smtp_response != NULL)
5279 uschar *code = US"503";
5280 int len = Ustrlen(rcpt_smtp_response);
5281 smtp_respond(code, 3, FALSE, US"All RCPT commands were rejected with "
5283 /* Responses from smtp_printf() will have \r\n on the end */
5284 if (len > 2 && rcpt_smtp_response[len-2] == '\r')
5285 rcpt_smtp_response[len-2] = 0;
5286 smtp_respond(code, 3, FALSE, rcpt_smtp_response);
5288 if (f.smtp_in_pipelining_advertised && last_was_rcpt)
5289 smtp_printf("503 Valid RCPT command must precede %s\r\n", FALSE,
5290 smtp_names[smtp_connection_had[smtp_ch_index-1]]);
5292 done = synprot_error(L_smtp_protocol_error, 503, NULL,
5293 smtp_connection_had[smtp_ch_index-1] == SCH_DATA
5294 ? US"valid RCPT command must precede DATA"
5295 : US"valid RCPT command must precede BDAT");
5297 if (chunking_state > CHUNKING_OFFERED)
5302 if (toomany && recipients_max_reject)
5304 sender_address = NULL; /* This will allow a new MAIL without RSET */
5305 sender_address_unrewritten = NULL;
5306 smtp_printf("554 Too many recipients\r\n", FALSE);
5310 if (chunking_state > CHUNKING_OFFERED)
5311 rc = OK; /* No predata ACL or go-ahead output for BDAT */
5314 /* If there is an ACL, re-check the synchronization afterwards, since the
5315 ACL may have delayed. To handle cutthrough delivery enforce a dummy call
5316 to get the DATA command sent. */
5318 if (acl_smtp_predata == NULL && cutthrough.cctx.sock < 0)
5322 uschar * acl = acl_smtp_predata ? acl_smtp_predata : US"accept";
5323 f.enable_dollar_recipients = TRUE;
5324 rc = acl_check(ACL_WHERE_PREDATA, NULL, acl, &user_msg,
5326 f.enable_dollar_recipients = FALSE;
5327 if (rc == OK && !check_sync())
5331 { /* Either the ACL failed the address, or it was deferred. */
5332 done = smtp_handle_acl_fail(ACL_WHERE_PREDATA, rc, user_msg, log_msg);
5338 smtp_user_msg(US"354", user_msg);
5341 "354 Enter message, ending with \".\" on a line by itself\r\n", FALSE);
5345 if (smtp_in) /* all ACKs needed to ramp window up for bulk data */
5346 (void) setsockopt(fileno(smtp_in), IPPROTO_TCP, TCP_QUICKACK,
5347 US &on, sizeof(on));
5350 message_ended = END_NOTENDED; /* Indicate in middle of data */
5361 if (!(address = parse_extract_address(smtp_cmd_data, &errmess,
5362 &start, &end, &recipient_domain, FALSE)))
5364 smtp_printf("501 %s\r\n", FALSE, errmess);
5368 if (!recipient_domain)
5369 if (!(recipient_domain = qualify_recipient(&address, smtp_cmd_data,
5373 if ((rc = acl_check(ACL_WHERE_VRFY, address, acl_smtp_vrfy,
5374 &user_msg, &log_msg)) != OK)
5375 done = smtp_handle_acl_fail(ACL_WHERE_VRFY, rc, user_msg, log_msg);
5379 address_item * addr = deliver_make_addr(address, FALSE);
5381 switch(verify_address(addr, NULL, vopt_is_recipient | vopt_qualify, -1,
5382 -1, -1, NULL, NULL, NULL))
5385 s = string_sprintf("250 <%s> is deliverable", address);
5389 s = (addr->user_message != NULL)?
5390 string_sprintf("451 <%s> %s", address, addr->user_message) :
5391 string_sprintf("451 Cannot resolve <%s> at this time", address);
5395 s = (addr->user_message != NULL)?
5396 string_sprintf("550 <%s> %s", address, addr->user_message) :
5397 string_sprintf("550 <%s> is not deliverable", address);
5398 log_write(0, LOG_MAIN, "VRFY failed for %s %s",
5399 smtp_cmd_argument, host_and_ident(TRUE));
5403 smtp_printf("%s\r\n", FALSE, s);
5411 rc = acl_check(ACL_WHERE_EXPN, NULL, acl_smtp_expn, &user_msg, &log_msg);
5413 done = smtp_handle_acl_fail(ACL_WHERE_EXPN, rc, user_msg, log_msg);
5416 BOOL save_log_testing_mode = f.log_testing_mode;
5417 f.address_test_mode = f.log_testing_mode = TRUE;
5418 (void) verify_address(deliver_make_addr(smtp_cmd_data, FALSE),
5419 smtp_out, vopt_is_recipient | vopt_qualify | vopt_expn, -1, -1, -1,
5421 f.address_test_mode = FALSE;
5422 f.log_testing_mode = save_log_testing_mode; /* true for -bh */
5431 if (!fl.tls_advertised)
5433 done = synprot_error(L_smtp_protocol_error, 503, NULL,
5434 US"STARTTLS command used when not advertised");
5438 /* Apply an ACL check if one is defined */
5440 if ( acl_smtp_starttls
5441 && (rc = acl_check(ACL_WHERE_STARTTLS, NULL, acl_smtp_starttls,
5442 &user_msg, &log_msg)) != OK
5445 done = smtp_handle_acl_fail(ACL_WHERE_STARTTLS, rc, user_msg, log_msg);
5449 /* RFC 2487 is not clear on when this command may be sent, though it
5450 does state that all information previously obtained from the client
5451 must be discarded if a TLS session is started. It seems reasonable to
5452 do an implied RSET when STARTTLS is received. */
5454 incomplete_transaction_log(US"STARTTLS");
5455 cancel_cutthrough_connection(TRUE, US"STARTTLS received");
5456 reset_point = smtp_reset(reset_point);
5458 cmd_list[CMD_LIST_STARTTLS].is_mail_cmd = FALSE;
5460 /* There's an attack where more data is read in past the STARTTLS command
5461 before TLS is negotiated, then assumed to be part of the secure session
5462 when used afterwards; we use segregated input buffers, so are not
5463 vulnerable, but we want to note when it happens and, for sheer paranoia,
5464 ensure that the buffer is "wiped".
5465 Pipelining sync checks will normally have protected us too, unless disabled
5466 by configuration. */
5468 if (receive_smtp_buffered())
5471 debug_printf("Non-empty input buffer after STARTTLS; naive attack?\n");
5472 if (tls_in.active.sock < 0)
5473 smtp_inend = smtp_inptr = smtp_inbuffer;
5474 /* and if TLS is already active, tls_server_start() should fail */
5477 /* There is nothing we value in the input buffer and if TLS is successfully
5478 negotiated, we won't use this buffer again; if TLS fails, we'll just read
5479 fresh content into it. The buffer contains arbitrary content from an
5480 untrusted remote source; eg: NOOP <shellcode>\r\nSTARTTLS\r\n
5481 It seems safest to just wipe away the content rather than leave it as a
5482 target to jump to. */
5484 memset(smtp_inbuffer, 0, IN_BUFFER_SIZE);
5486 /* Attempt to start up a TLS session, and if successful, discard all
5487 knowledge that was obtained previously. At least, that's what the RFC says,
5488 and that's what happens by default. However, in order to work round YAEB,
5489 there is an option to remember the esmtp state. Sigh.
5491 We must allow for an extra EHLO command and an extra AUTH command after
5492 STARTTLS that don't add to the nonmail command count. */
5495 if ((rc = tls_server_start(tls_require_ciphers, &s)) == OK)
5497 if (!tls_remember_esmtp)
5498 fl.helo_seen = fl.esmtp = fl.auth_advertised = f.smtp_in_pipelining_advertised = FALSE;
5499 cmd_list[CMD_LIST_EHLO].is_mail_cmd = TRUE;
5500 cmd_list[CMD_LIST_AUTH].is_mail_cmd = TRUE;
5501 cmd_list[CMD_LIST_TLS_AUTH].is_mail_cmd = TRUE;
5502 if (sender_helo_name)
5504 sender_helo_name = NULL;
5505 host_build_sender_fullhost(); /* Rebuild */
5506 set_process_info("handling incoming TLS connection from %s",
5507 host_and_ident(FALSE));
5510 (sender_host_address ? protocols : protocols_local)
5512 ? pextend + (sender_host_authenticated ? pauthed : 0)
5514 + (tls_in.active.sock >= 0 ? pcrpted : 0)
5517 sender_host_auth_pubname = sender_host_authenticated = NULL;
5518 authenticated_id = NULL;
5519 sync_cmd_limit = NON_SYNC_CMD_NON_PIPELINING;
5520 DEBUG(D_tls) debug_printf("TLS active\n");
5521 break; /* Successful STARTTLS */
5524 (void) smtp_log_tls_fail(s);
5526 /* Some local configuration problem was discovered before actually trying
5527 to do a TLS handshake; give a temporary error. */
5531 smtp_printf("454 TLS currently unavailable\r\n", FALSE);
5535 /* Hard failure. Reject everything except QUIT or closed connection. One
5536 cause for failure is a nested STARTTLS, in which case tls_in.active remains
5537 set, but we must still reject all incoming commands. Another is a handshake
5538 failure - and there may some encrypted data still in the pipe to us, which we
5539 see as garbage commands. */
5541 DEBUG(D_tls) debug_printf("TLS failed to start\n");
5542 while (done <= 0) switch(smtp_read_command(FALSE, GETC_BUFFER_UNLIMITED))
5545 log_write(L_smtp_connection, LOG_MAIN, "%s closed by EOF",
5546 smtp_get_connection_info());
5547 smtp_notquit_exit(US"tls-failed", NULL, NULL);
5551 /* It is perhaps arguable as to which exit ACL should be called here,
5552 but as it is probably a situation that almost never arises, it
5553 probably doesn't matter. We choose to call the real QUIT ACL, which in
5554 some sense is perhaps "right". */
5559 && ((rc = acl_check(ACL_WHERE_QUIT, NULL, acl_smtp_quit, &user_msg,
5560 &log_msg)) == ERROR))
5561 log_write(0, LOG_MAIN|LOG_PANIC, "ACL for QUIT returned ERROR: %s",
5564 smtp_respond(US"221", 3, TRUE, user_msg);
5566 smtp_printf("221 %s closing connection\r\n", FALSE, smtp_active_hostname);
5567 log_write(L_smtp_connection, LOG_MAIN, "%s closed by QUIT",
5568 smtp_get_connection_info());
5573 smtp_printf("554 Security failure\r\n", FALSE);
5576 tls_close(NULL, TLS_SHUTDOWN_NOWAIT);
5581 /* The ACL for QUIT is provided for gathering statistical information or
5582 similar; it does not affect the response code, but it can supply a custom
5586 smtp_quit_handler(&user_msg, &log_msg);
5592 smtp_rset_handler();
5593 cancel_cutthrough_connection(TRUE, US"RSET received");
5594 reset_point = smtp_reset(reset_point);
5601 smtp_printf("250 OK\r\n", FALSE);
5605 /* Show ETRN/EXPN/VRFY if there's an ACL for checking hosts; if actually
5606 used, a check will be done for permitted hosts. Show STARTTLS only if not
5607 already in a TLS session and if it would be advertised in the EHLO
5612 smtp_printf("214-Commands supported:\r\n", TRUE);
5616 Ustrcat(buffer, US" AUTH");
5618 if (tls_in.active.sock < 0 &&
5619 verify_check_host(&tls_advertise_hosts) != FAIL)
5620 Ustrcat(buffer, US" STARTTLS");
5622 Ustrcat(buffer, US" HELO EHLO MAIL RCPT DATA BDAT");
5623 Ustrcat(buffer, US" NOOP QUIT RSET HELP");
5624 if (acl_smtp_etrn) Ustrcat(buffer, US" ETRN");
5625 if (acl_smtp_expn) Ustrcat(buffer, US" EXPN");
5626 if (acl_smtp_vrfy) Ustrcat(buffer, US" VRFY");
5627 smtp_printf("214%s\r\n", FALSE, buffer);
5633 incomplete_transaction_log(US"connection lost");
5634 smtp_notquit_exit(US"connection-lost", US"421",
5635 US"%s lost input connection", smtp_active_hostname);
5637 /* Don't log by default unless in the middle of a message, as some mailers
5638 just drop the call rather than sending QUIT, and it clutters up the logs.
5641 if (sender_address || recipients_count > 0)
5642 log_write(L_lost_incoming_connection, LOG_MAIN,
5643 "unexpected %s while reading SMTP command from %s%s%s D=%s",
5644 f.sender_host_unknown ? "EOF" : "disconnection",
5645 f.tcp_in_fastopen_logged
5648 ? f.tcp_in_fastopen_data ? US"TFO* " : US"TFO "
5650 host_and_ident(FALSE), smtp_read_error,
5651 string_timesince(&smtp_connection_start)
5655 log_write(L_smtp_connection, LOG_MAIN, "%s %slost%s D=%s",
5656 smtp_get_connection_info(),
5657 f.tcp_in_fastopen && !f.tcp_in_fastopen_logged ? US"TFO " : US"",
5659 string_timesince(&smtp_connection_start)
5670 done = synprot_error(L_smtp_protocol_error, 503, NULL,
5671 US"ETRN is not permitted inside a transaction");
5675 log_write(L_etrn, LOG_MAIN, "ETRN %s received from %s", smtp_cmd_argument,
5676 host_and_ident(FALSE));
5678 if ((rc = acl_check(ACL_WHERE_ETRN, NULL, acl_smtp_etrn,
5679 &user_msg, &log_msg)) != OK)
5681 done = smtp_handle_acl_fail(ACL_WHERE_ETRN, rc, user_msg, log_msg);
5685 /* Compute the serialization key for this command. */
5687 etrn_serialize_key = string_sprintf("etrn-%s\n", smtp_cmd_data);
5689 /* If a command has been specified for running as a result of ETRN, we
5690 permit any argument to ETRN. If not, only the # standard form is permitted,
5691 since that is strictly the only kind of ETRN that can be implemented
5692 according to the RFC. */
5694 if (smtp_etrn_command)
5698 etrn_command = smtp_etrn_command;
5699 deliver_domain = smtp_cmd_data;
5700 rc = transport_set_up_command(&argv, smtp_etrn_command, TRUE, 0, NULL,
5701 US"ETRN processing", &error);
5702 deliver_domain = NULL;
5705 log_write(0, LOG_MAIN|LOG_PANIC, "failed to set up ETRN command: %s",
5707 smtp_printf("458 Internal failure\r\n", FALSE);
5712 /* Else set up to call Exim with the -R option. */
5716 if (*smtp_cmd_data++ != '#')
5718 done = synprot_error(L_smtp_syntax_error, 501, NULL,
5719 US"argument must begin with #");
5722 etrn_command = US"exim -R";
5723 argv = CUSS child_exec_exim(CEE_RETURN_ARGV, TRUE, NULL, TRUE,
5724 *queue_name ? 4 : 2,
5725 US"-R", smtp_cmd_data,
5726 US"-MCG", queue_name);
5729 /* If we are host-testing, don't actually do anything. */
5735 debug_printf("ETRN command is: %s\n", etrn_command);
5736 debug_printf("ETRN command execution skipped\n");
5738 if (user_msg == NULL) smtp_printf("250 OK\r\n", FALSE);
5739 else smtp_user_msg(US"250", user_msg);
5744 /* If ETRN queue runs are to be serialized, check the database to
5745 ensure one isn't already running. */
5747 if (smtp_etrn_serialize && !enq_start(etrn_serialize_key, 1))
5749 smtp_printf("458 Already processing %s\r\n", FALSE, smtp_cmd_data);
5753 /* Fork a child process and run the command. We don't want to have to
5754 wait for the process at any point, so set SIGCHLD to SIG_IGN before
5755 forking. It should be set that way anyway for external incoming SMTP,
5756 but we save and restore to be tidy. If serialization is required, we
5757 actually run the command in yet another process, so we can wait for it
5758 to complete and then remove the serialization lock. */
5760 oldsignal = signal(SIGCHLD, SIG_IGN);
5762 if ((pid = fork()) == 0)
5764 smtp_input = FALSE; /* This process is not associated with the */
5765 (void)fclose(smtp_in); /* SMTP call any more. */
5766 (void)fclose(smtp_out);
5768 signal(SIGCHLD, SIG_DFL); /* Want to catch child */
5770 /* If not serializing, do the exec right away. Otherwise, fork down
5771 into another process. */
5773 if (!smtp_etrn_serialize || (pid = fork()) == 0)
5775 DEBUG(D_exec) debug_print_argv(argv);
5776 exim_nullstd(); /* Ensure std{in,out,err} exist */
5777 execv(CS argv[0], (char *const *)argv);
5778 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "exec of \"%s\" (ETRN) failed: %s",
5779 etrn_command, strerror(errno));
5780 _exit(EXIT_FAILURE); /* paranoia */
5783 /* Obey this if smtp_serialize and the 2nd fork yielded non-zero. That
5784 is, we are in the first subprocess, after forking again. All we can do
5785 for a failing fork is to log it. Otherwise, wait for the 2nd process to
5786 complete, before removing the serialization. */
5789 log_write(0, LOG_MAIN|LOG_PANIC, "2nd fork for serialized ETRN "
5790 "failed: %s", strerror(errno));
5794 DEBUG(D_any) debug_printf("waiting for serialized ETRN process %d\n",
5796 (void)wait(&status);
5797 DEBUG(D_any) debug_printf("serialized ETRN process %d ended\n",
5801 enq_end(etrn_serialize_key);
5802 exim_underbar_exit(EXIT_SUCCESS);
5805 /* Back in the top level SMTP process. Check that we started a subprocess
5806 and restore the signal state. */
5810 log_write(0, LOG_MAIN|LOG_PANIC, "fork of process for ETRN failed: %s",
5812 smtp_printf("458 Unable to fork process\r\n", FALSE);
5813 if (smtp_etrn_serialize) enq_end(etrn_serialize_key);
5817 smtp_printf("250 OK\r\n", FALSE);
5819 smtp_user_msg(US"250", user_msg);
5821 signal(SIGCHLD, oldsignal);
5826 done = synprot_error(L_smtp_syntax_error, 501, NULL,
5827 US"unexpected argument data");
5831 /* This currently happens only for NULLs, but could be extended. */
5834 done = synprot_error(L_smtp_syntax_error, 0, NULL, /* Just logs */
5835 US"NUL character(s) present (shown as '?')");
5836 smtp_printf("501 NUL characters are not allowed in SMTP commands\r\n",
5843 if (smtp_inend >= smtp_inbuffer + IN_BUFFER_SIZE)
5844 smtp_inend = smtp_inbuffer + IN_BUFFER_SIZE - 1;
5845 c = smtp_inend - smtp_inptr;
5846 if (c > 150) c = 150; /* limit logged amount */
5848 incomplete_transaction_log(US"sync failure");
5849 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP protocol synchronization error "
5850 "(next input sent too soon: pipelining was%s advertised): "
5851 "rejected \"%s\" %s next input=\"%s\"",
5852 f.smtp_in_pipelining_advertised ? "" : " not",
5853 smtp_cmd_buffer, host_and_ident(TRUE),
5854 string_printing(smtp_inptr));
5855 smtp_notquit_exit(US"synchronization-error", US"554",
5856 US"SMTP synchronization error");
5857 done = 1; /* Pretend eof - drops connection */
5861 case TOO_MANY_NONMAIL_CMD:
5862 s = smtp_cmd_buffer;
5863 while (*s != 0 && !isspace(*s)) s++;
5864 incomplete_transaction_log(US"too many non-mail commands");
5865 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
5866 "nonmail commands (last was \"%.*s\")", host_and_ident(FALSE),
5867 (int)(s - smtp_cmd_buffer), smtp_cmd_buffer);
5868 smtp_notquit_exit(US"bad-commands", US"554", US"Too many nonmail commands");
5869 done = 1; /* Pretend eof - drops connection */
5872 #ifdef SUPPORT_PROXY
5873 case PROXY_FAIL_IGNORE_CMD:
5874 smtp_printf("503 Command refused, required Proxy negotiation failed\r\n", FALSE);
5879 if (unknown_command_count++ >= smtp_max_unknown_commands)
5881 log_write(L_smtp_syntax_error, LOG_MAIN,
5882 "SMTP syntax error in \"%s\" %s %s",
5883 string_printing(smtp_cmd_buffer), host_and_ident(TRUE),
5884 US"unrecognized command");
5885 incomplete_transaction_log(US"unrecognized command");
5886 smtp_notquit_exit(US"bad-commands", US"500",
5887 US"Too many unrecognized commands");
5889 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
5890 "unrecognized commands (last was \"%s\")", host_and_ident(FALSE),
5891 string_printing(smtp_cmd_buffer));
5894 done = synprot_error(L_smtp_syntax_error, 500, NULL,
5895 US"unrecognized command");
5899 /* This label is used by goto's inside loops that want to break out to
5900 the end of the command-processing loop. */
5903 last_was_rej_mail = was_rej_mail; /* Remember some last commands for */
5904 last_was_rcpt = was_rcpt; /* protocol error handling */
5908 return done - 2; /* Convert yield values */
5914 authres_smtpauth(gstring * g)
5916 if (!sender_host_authenticated)
5919 g = string_append(g, 2, US";\n\tauth=pass (", sender_host_auth_pubname);
5921 if (Ustrcmp(sender_host_auth_pubname, "tls") != 0)
5922 g = string_append(g, 2, US") smtp.auth=", authenticated_id);
5923 else if (authenticated_id)
5924 g = string_append(g, 2, US") x509.auth=", authenticated_id);
5926 g = string_catn(g, US") reason=x509.auth", 17);
5928 if (authenticated_sender)
5929 g = string_append(g, 2, US" smtp.mailfrom=", authenticated_sender);
5937 /* End of smtp_in.c */