1 /*************************************************
2 * Exim - an Internet mail transport agent *
3 *************************************************/
5 /* Copyright (c) University of Cambridge 1995 - 2018 */
6 /* Copyright (c) The Exim Maintainers 2020 */
7 /* See the file NOTICE for conditions of use and distribution. */
9 /* Functions for handling an incoming SMTP call. */
16 /* Initialize for TCP wrappers if so configured. It appears that the macro
17 HAVE_IPV6 is used in some versions of the tcpd.h header, so we unset it before
18 including that header, and restore its value afterwards. */
20 #ifdef USE_TCP_WRAPPERS
23 #define EXIM_HAVE_IPV6
29 #define HAVE_IPV6 TRUE
32 int allow_severity = LOG_INFO;
33 int deny_severity = LOG_NOTICE;
34 uschar *tcp_wrappers_name;
38 /* Size of buffer for reading SMTP commands. We used to use 512, as defined
39 by RFC 821. However, RFC 1869 specifies that this must be increased for SMTP
40 commands that accept arguments, and this in particular applies to AUTH, where
41 the data can be quite long. More recently this value was 2048 in Exim;
42 however, RFC 4954 (circa 2007) recommends 12288 bytes to handle AUTH. Clients
43 such as Thunderbird will send an AUTH with an initial-response for GSSAPI.
44 The maximum size of a Kerberos ticket under Windows 2003 is 12000 bytes, and
45 we need room to handle large base64-encoded AUTHs for GSSAPI.
48 #define SMTP_CMD_BUFFER_SIZE 16384
50 /* Size of buffer for reading SMTP incoming packets */
52 #define IN_BUFFER_SIZE 8192
54 /* Structure for SMTP command list */
61 short int is_mail_cmd;
64 /* Codes for identifying commands. We order them so that those that come first
65 are those for which synchronization is always required. Checking this can help
69 /* These commands are required to be synchronized, i.e. to be the last in a
70 block of commands when pipelining. */
72 HELO_CMD, EHLO_CMD, DATA_CMD, /* These are listed in the pipelining */
73 VRFY_CMD, EXPN_CMD, NOOP_CMD, /* RFC as requiring synchronization */
74 ETRN_CMD, /* This by analogy with TURN from the RFC */
75 STARTTLS_CMD, /* Required by the STARTTLS RFC */
76 TLS_AUTH_CMD, /* auto-command at start of SSL */
78 /* This is a dummy to identify the non-sync commands when pipelining */
80 NON_SYNC_CMD_PIPELINING,
82 /* These commands need not be synchronized when pipelining */
84 MAIL_CMD, RCPT_CMD, RSET_CMD,
86 /* This is a dummy to identify the non-sync commands when not pipelining */
88 NON_SYNC_CMD_NON_PIPELINING,
90 /* RFC3030 section 2: "After all MAIL and RCPT responses are collected and
91 processed the message is sent using a series of BDAT commands"
92 implies that BDAT should be synchronized. However, we see Google, at least,
93 sending MAIL,RCPT,BDAT-LAST in a single packet, clearly not waiting for
94 processing of the RCPT response(s). We shall do the same, and not require
95 synch for BDAT. Worse, as the chunk may (very likely will) follow the
96 command-header in the same packet we cannot do the usual "is there any
97 follow-on data after the command line" even for non-pipeline mode.
98 So we'll need an explicit check after reading the expected chunk amount
99 when non-pipe, before sending the ACK. */
103 /* I have been unable to find a statement about the use of pipelining
104 with AUTH, so to be on the safe side it is here, though I kind of feel
105 it should be up there with the synchronized commands. */
109 /* I'm not sure about these, but I don't think they matter. */
114 PROXY_FAIL_IGNORE_CMD,
117 /* These are specials that don't correspond to actual commands */
119 EOF_CMD, OTHER_CMD, BADARG_CMD, BADCHAR_CMD, BADSYN_CMD,
120 TOO_MANY_NONMAIL_CMD };
123 /* This is a convenience macro for adding the identity of an SMTP command
124 to the circular buffer that holds a list of the last n received. */
127 smtp_connection_had[smtp_ch_index++] = n; \
128 if (smtp_ch_index >= SMTP_HBUFF_SIZE) smtp_ch_index = 0
131 /*************************************************
132 * Local static variables *
133 *************************************************/
136 BOOL auth_advertised :1;
138 BOOL tls_advertised :1;
140 BOOL dsn_advertised :1;
142 BOOL helo_verify_required :1;
145 BOOL helo_accept_junk :1;
146 #ifndef DISABLE_PIPE_CONNECT
147 BOOL pipe_connect_acceptable :1;
149 BOOL rcpt_smtp_response_same :1;
150 BOOL rcpt_in_progress :1;
151 BOOL smtp_exit_function_called :1;
153 BOOL smtputf8_advertised :1;
156 .helo_verify_required = FALSE,
157 .helo_verify = FALSE,
158 .smtp_exit_function_called = FALSE,
161 static auth_instance *authenticated_by;
162 static int count_nonmail;
163 static int nonmail_command_count;
164 static int synprot_error_count;
165 static int unknown_command_count;
166 static int sync_cmd_limit;
167 static int smtp_write_error = 0;
169 static uschar *rcpt_smtp_response;
170 static uschar *smtp_data_buffer;
171 static uschar *smtp_cmd_data;
173 /* We need to know the position of RSET, HELO, EHLO, AUTH, and STARTTLS. Their
174 final fields of all except AUTH are forced TRUE at the start of a new message
175 setup, to allow one of each between messages that is not counted as a nonmail
176 command. (In fact, only one of HELO/EHLO is not counted.) Also, we have to
177 allow a new EHLO after starting up TLS.
179 AUTH is "falsely" labelled as a mail command initially, so that it doesn't get
180 counted. However, the flag is changed when AUTH is received, so that multiple
181 failing AUTHs will eventually hit the limit. After a successful AUTH, another
182 AUTH is already forbidden. After a TLS session is started, AUTH's flag is again
183 forced TRUE, to allow for the re-authentication that can happen at that point.
185 QUIT is also "falsely" labelled as a mail command so that it doesn't up the
186 count of non-mail commands and possibly provoke an error.
188 tls_auth is a pseudo-command, never expected in input. It is activated
189 on TLS startup and looks for a tls authenticator. */
191 static smtp_cmd_list cmd_list[] = {
192 /* name len cmd has_arg is_mail_cmd */
194 { "rset", sizeof("rset")-1, RSET_CMD, FALSE, FALSE }, /* First */
195 { "helo", sizeof("helo")-1, HELO_CMD, TRUE, FALSE },
196 { "ehlo", sizeof("ehlo")-1, EHLO_CMD, TRUE, FALSE },
197 { "auth", sizeof("auth")-1, AUTH_CMD, TRUE, TRUE },
199 { "starttls", sizeof("starttls")-1, STARTTLS_CMD, FALSE, FALSE },
200 { "tls_auth", 0, TLS_AUTH_CMD, FALSE, FALSE },
203 /* If you change anything above here, also fix the definitions below. */
205 { "mail from:", sizeof("mail from:")-1, MAIL_CMD, TRUE, TRUE },
206 { "rcpt to:", sizeof("rcpt to:")-1, RCPT_CMD, TRUE, TRUE },
207 { "data", sizeof("data")-1, DATA_CMD, FALSE, TRUE },
208 { "bdat", sizeof("bdat")-1, BDAT_CMD, TRUE, TRUE },
209 { "quit", sizeof("quit")-1, QUIT_CMD, FALSE, TRUE },
210 { "noop", sizeof("noop")-1, NOOP_CMD, TRUE, FALSE },
211 { "etrn", sizeof("etrn")-1, ETRN_CMD, TRUE, FALSE },
212 { "vrfy", sizeof("vrfy")-1, VRFY_CMD, TRUE, FALSE },
213 { "expn", sizeof("expn")-1, EXPN_CMD, TRUE, FALSE },
214 { "help", sizeof("help")-1, HELP_CMD, TRUE, FALSE }
217 static smtp_cmd_list *cmd_list_end =
218 cmd_list + sizeof(cmd_list)/sizeof(smtp_cmd_list);
220 #define CMD_LIST_RSET 0
221 #define CMD_LIST_HELO 1
222 #define CMD_LIST_EHLO 2
223 #define CMD_LIST_AUTH 3
224 #define CMD_LIST_STARTTLS 4
225 #define CMD_LIST_TLS_AUTH 5
227 /* This list of names is used for performing the smtp_no_mail logging action.
228 It must be kept in step with the SCH_xxx enumerations. */
230 uschar * smtp_names[] =
232 US"NONE", US"AUTH", US"DATA", US"BDAT", US"EHLO", US"ETRN", US"EXPN",
233 US"HELO", US"HELP", US"MAIL", US"NOOP", US"QUIT", US"RCPT", US"RSET",
234 US"STARTTLS", US"VRFY" };
236 static uschar *protocols_local[] = {
237 US"local-smtp", /* HELO */
238 US"local-smtps", /* The rare case EHLO->STARTTLS->HELO */
239 US"local-esmtp", /* EHLO */
240 US"local-esmtps", /* EHLO->STARTTLS->EHLO */
241 US"local-esmtpa", /* EHLO->AUTH */
242 US"local-esmtpsa" /* EHLO->STARTTLS->EHLO->AUTH */
244 static uschar *protocols[] = {
246 US"smtps", /* The rare case EHLO->STARTTLS->HELO */
247 US"esmtp", /* EHLO */
248 US"esmtps", /* EHLO->STARTTLS->EHLO */
249 US"esmtpa", /* EHLO->AUTH */
250 US"esmtpsa" /* EHLO->STARTTLS->EHLO->AUTH */
255 #define pcrpted 1 /* added to pextend or pnormal */
256 #define pauthed 2 /* added to pextend */
258 /* Sanity check and validate optional args to MAIL FROM: envelope */
261 ENV_MAIL_OPT_SIZE, ENV_MAIL_OPT_BODY, ENV_MAIL_OPT_AUTH,
265 ENV_MAIL_OPT_RET, ENV_MAIL_OPT_ENVID,
271 uschar * name; /* option requested during MAIL cmd */
272 int value; /* enum type */
273 BOOL need_value; /* TRUE requires value (name=value pair format)
274 FALSE is a singleton */
276 static env_mail_type_t env_mail_type_list[] = {
277 { US"SIZE", ENV_MAIL_OPT_SIZE, TRUE },
278 { US"BODY", ENV_MAIL_OPT_BODY, TRUE },
279 { US"AUTH", ENV_MAIL_OPT_AUTH, TRUE },
281 { US"PRDR", ENV_MAIL_OPT_PRDR, FALSE },
283 { US"RET", ENV_MAIL_OPT_RET, TRUE },
284 { US"ENVID", ENV_MAIL_OPT_ENVID, TRUE },
286 { US"SMTPUTF8",ENV_MAIL_OPT_UTF8, FALSE }, /* rfc6531 */
288 /* keep this the last entry */
289 { US"NULL", ENV_MAIL_OPT_NULL, FALSE },
292 /* When reading SMTP from a remote host, we have to use our own versions of the
293 C input-reading functions, in order to be able to flush the SMTP output only
294 when about to read more data from the socket. This is the only way to get
295 optimal performance when the client is using pipelining. Flushing for every
296 command causes a separate packet and reply packet each time; saving all the
297 responses up (when pipelining) combines them into one packet and one response.
299 For simplicity, these functions are used for *all* SMTP input, not only when
300 receiving over a socket. However, after setting up a secure socket (SSL), input
301 is read via the OpenSSL library, and another set of functions is used instead
304 These functions are set in the receive_getc etc. variables and called with the
305 same interface as the C functions. However, since there can only ever be
306 one incoming SMTP call, we just use a single buffer and flags. There is no need
307 to implement a complicated private FILE-like structure.*/
309 static uschar *smtp_inbuffer;
310 static uschar *smtp_inptr;
311 static uschar *smtp_inend;
312 static int smtp_had_eof;
313 static int smtp_had_error;
316 /* forward declarations */
317 static int smtp_read_command(BOOL check_sync, unsigned buffer_lim);
318 static int synprot_error(int type, int code, uschar *data, uschar *errmess);
319 static void smtp_quit_handler(uschar **, uschar **);
320 static void smtp_rset_handler(void);
322 /*************************************************
323 * Recheck synchronization *
324 *************************************************/
326 /* Synchronization checks can never be perfect because a packet may be on its
327 way but not arrived when the check is done. Normally, the checks happen when
328 commands are read: Exim ensures that there is no more input in the input buffer.
329 In normal cases, the response to the command will be fast, and there is no
332 However, for some commands an ACL is run, and that can include delays. In those
333 cases, it is useful to do another check on the input just before sending the
334 response. This also applies at the start of a connection. This function does
335 that check by means of the select() function, as long as the facility is not
336 disabled or inappropriate. A failure of select() is ignored.
338 When there is unwanted input, we read it so that it appears in the log of the
342 Returns: TRUE if all is well; FALSE if there is input pending
346 wouldblock_reading(void)
350 struct timeval tzero = {.tv_sec = 0, .tv_usec = 0};
353 if (tls_in.active.sock >= 0)
354 return !tls_could_read();
357 if (smtp_inptr < smtp_inend)
360 fd = fileno(smtp_in);
363 rc = select(fd + 1, (SELECT_ARG2_TYPE *)&fds, NULL, NULL, &tzero);
365 if (rc <= 0) return TRUE; /* Not ready to read */
366 rc = smtp_getc(GETC_BUFFER_UNLIMITED);
367 if (rc < 0) return TRUE; /* End of file or error */
376 if (!smtp_enforce_sync || !sender_host_address || f.sender_host_notsocket)
379 return wouldblock_reading();
383 /* If there's input waiting (and we're doing pipelineing) then we can pipeline
384 a reponse with the one following. */
387 pipeline_response(void)
389 if ( !smtp_enforce_sync || !sender_host_address
390 || f.sender_host_notsocket || !f.smtp_in_pipelining_advertised)
393 if (wouldblock_reading()) return FALSE;
394 f.smtp_in_pipelining_used = TRUE;
399 #ifndef DISABLE_PIPE_CONNECT
401 pipeline_connect_sends(void)
403 if (!sender_host_address || f.sender_host_notsocket || !fl.pipe_connect_acceptable)
406 if (wouldblock_reading()) return FALSE;
407 f.smtp_in_early_pipe_used = TRUE;
412 /*************************************************
413 * Log incomplete transactions *
414 *************************************************/
416 /* This function is called after a transaction has been aborted by RSET, QUIT,
417 connection drops or other errors. It logs the envelope information received
418 so far in order to preserve address verification attempts.
420 Argument: string to indicate what aborted the transaction
425 incomplete_transaction_log(uschar *what)
427 if (!sender_address /* No transaction in progress */
428 || !LOGGING(smtp_incomplete_transaction))
431 /* Build list of recipients for logging */
433 if (recipients_count > 0)
435 raw_recipients = store_get(recipients_count * sizeof(uschar *), FALSE);
436 for (int i = 0; i < recipients_count; i++)
437 raw_recipients[i] = recipients_list[i].address;
438 raw_recipients_count = recipients_count;
441 log_write(L_smtp_incomplete_transaction, LOG_MAIN|LOG_SENDER|LOG_RECIPIENTS,
442 "%s incomplete transaction (%s)", host_and_ident(TRUE), what);
449 smtp_command_timeout_exit(void)
451 log_write(L_lost_incoming_connection,
452 LOG_MAIN, "SMTP command timeout on%s connection from %s",
453 tls_in.active.sock >= 0 ? " TLS" : "", host_and_ident(FALSE));
454 if (smtp_batched_input)
455 moan_smtp_batch(NULL, "421 SMTP command timeout"); /* Does not return */
456 smtp_notquit_exit(US"command-timeout", US"421",
457 US"%s: SMTP command timeout - closing connection",
458 smtp_active_hostname);
459 exim_exit(EXIT_FAILURE);
463 smtp_command_sigterm_exit(void)
465 log_write(0, LOG_MAIN, "%s closed after SIGTERM", smtp_get_connection_info());
466 if (smtp_batched_input)
467 moan_smtp_batch(NULL, "421 SIGTERM received"); /* Does not return */
468 smtp_notquit_exit(US"signal-exit", US"421",
469 US"%s: Service not available - closing connection", smtp_active_hostname);
470 exim_exit(EXIT_FAILURE);
474 smtp_data_timeout_exit(void)
476 log_write(L_lost_incoming_connection,
477 LOG_MAIN, "SMTP data timeout (message abandoned) on connection from %s F=<%s>",
478 sender_fullhost ? sender_fullhost : US"local process", sender_address);
479 receive_bomb_out(US"data-timeout", US"SMTP incoming data timeout");
480 /* Does not return */
484 smtp_data_sigint_exit(void)
486 log_write(0, LOG_MAIN, "%s closed after %s",
487 smtp_get_connection_info(), had_data_sigint == SIGTERM ? "SIGTERM":"SIGINT");
488 receive_bomb_out(US"signal-exit",
489 US"Service not available - SIGTERM or SIGINT received");
490 /* Does not return */
495 /* Refill the buffer, and notify DKIM verification code.
496 Return false for error or EOF.
500 smtp_refill(unsigned lim)
503 if (!smtp_out) return FALSE;
505 if (smtp_receive_timeout > 0) ALARM(smtp_receive_timeout);
507 /* Limit amount read, so non-message data is not fed to DKIM.
508 Take care to not touch the safety NUL at the end of the buffer. */
510 rc = read(fileno(smtp_in), smtp_inbuffer, MIN(IN_BUFFER_SIZE-1, lim));
512 if (smtp_receive_timeout > 0) ALARM_CLR(0);
515 /* Must put the error text in fixed store, because this might be during
516 header reading, where it releases unused store above the header. */
519 if (had_command_timeout) /* set by signal handler */
520 smtp_command_timeout_exit(); /* does not return */
521 if (had_command_sigterm)
522 smtp_command_sigterm_exit();
523 if (had_data_timeout)
524 smtp_data_timeout_exit();
526 smtp_data_sigint_exit();
528 smtp_had_error = save_errno;
529 smtp_read_error = string_copy_perm(
530 string_sprintf(" (error: %s)", strerror(save_errno)), FALSE);
537 dkim_exim_verify_feed(smtp_inbuffer, rc);
539 smtp_inend = smtp_inbuffer + rc;
540 smtp_inptr = smtp_inbuffer;
544 /*************************************************
545 * SMTP version of getc() *
546 *************************************************/
548 /* This gets the next byte from the SMTP input buffer. If the buffer is empty,
549 it flushes the output, and refills the buffer, with a timeout. The signal
550 handler is set appropriately by the calling function. This function is not used
551 after a connection has negotiated itself into an TLS/SSL state.
553 Arguments: lim Maximum amount to read/buffer
554 Returns: the next character or EOF
558 smtp_getc(unsigned lim)
560 if (smtp_inptr >= smtp_inend)
561 if (!smtp_refill(lim))
563 return *smtp_inptr++;
567 smtp_getbuf(unsigned * len)
572 if (smtp_inptr >= smtp_inend)
573 if (!smtp_refill(*len))
574 { *len = 0; return NULL; }
576 if ((size = smtp_inend - smtp_inptr) > *len) size = *len;
584 smtp_get_cache(unsigned lim)
587 int n = smtp_inend - smtp_inptr;
591 dkim_exim_verify_feed(smtp_inptr, n);
596 /* Forward declarations */
597 static inline void bdat_push_receive_functions(void);
598 static inline void bdat_pop_receive_functions(void);
601 /* Get a byte from the smtp input, in CHUNKING mode. Handle ack of the
602 previous BDAT chunk and getting new ones when we run out. Uses the
603 underlying smtp_getc or tls_getc both for that and for getting the
604 (buffered) data byte. EOD signals (an expected) no further data.
605 ERR signals a protocol error, and EOF a closed input stream.
607 Called from read_bdat_smtp() in receive.c for the message body, but also
608 by the headers read loop in receive_msg(); manipulates chunking_state
609 to handle the BDAT command/response.
610 Placed here due to the correlation with the above smtp_getc(), which it wraps,
611 and also by the need to do smtp command/response handling.
613 Arguments: lim (ignored)
614 Returns: the next character or ERR, EOD or EOF
618 bdat_getc(unsigned lim)
620 uschar * user_msg = NULL;
629 if (chunking_data_left > 0)
630 return lwr_receive_getc(chunking_data_left--);
632 bdat_pop_receive_functions();
634 dkim_save = dkim_collect_input;
635 dkim_collect_input = 0;
638 /* Unless PIPELINING was offered, there should be no next command
639 until after we ack that chunk */
641 if (!f.smtp_in_pipelining_advertised && !check_sync())
643 unsigned n = smtp_inend - smtp_inptr;
646 incomplete_transaction_log(US"sync failure");
647 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP protocol synchronization error "
648 "(next input sent too soon: pipelining was not advertised): "
649 "rejected \"%s\" %s next input=\"%s\"%s",
650 smtp_cmd_buffer, host_and_ident(TRUE),
651 string_printing(string_copyn(smtp_inptr, n)),
652 smtp_inend - smtp_inptr > n ? "..." : "");
653 (void) synprot_error(L_smtp_protocol_error, 554, NULL,
654 US"SMTP synchronization error");
655 goto repeat_until_rset;
658 /* If not the last, ack the received chunk. The last response is delayed
659 until after the data ACL decides on it */
661 if (chunking_state == CHUNKING_LAST)
664 dkim_collect_input = dkim_save;
665 dkim_exim_verify_feed(NULL, 0); /* notify EOD */
666 dkim_collect_input = 0;
671 smtp_printf("250 %u byte chunk received\r\n", FALSE, chunking_datasize);
672 chunking_state = CHUNKING_OFFERED;
673 DEBUG(D_receive) debug_printf("chunking state %d\n", (int)chunking_state);
675 /* Expect another BDAT cmd from input. RFC 3030 says nothing about
676 QUIT, RSET or NOOP but handling them seems obvious */
679 switch(smtp_read_command(TRUE, 1))
682 (void) synprot_error(L_smtp_protocol_error, 503, NULL,
683 US"only BDAT permissible after non-LAST BDAT");
686 switch(smtp_read_command(TRUE, 1))
688 case QUIT_CMD: smtp_quit_handler(&user_msg, &log_msg); /*FALLTHROUGH */
689 case EOF_CMD: return EOF;
690 case RSET_CMD: smtp_rset_handler(); return ERR;
691 default: if (synprot_error(L_smtp_protocol_error, 503, NULL,
692 US"only RSET accepted now") > 0)
694 goto repeat_until_rset;
698 smtp_quit_handler(&user_msg, &log_msg);
709 smtp_printf("250 OK\r\n", FALSE);
716 if (sscanf(CS smtp_cmd_data, "%u %n", &chunking_datasize, &n) < 1)
718 (void) synprot_error(L_smtp_protocol_error, 501, NULL,
719 US"missing size for BDAT command");
722 chunking_state = strcmpic(smtp_cmd_data+n, US"LAST") == 0
723 ? CHUNKING_LAST : CHUNKING_ACTIVE;
724 chunking_data_left = chunking_datasize;
725 DEBUG(D_receive) debug_printf("chunking state %d, %d bytes\n",
726 (int)chunking_state, chunking_data_left);
728 if (chunking_datasize == 0)
729 if (chunking_state == CHUNKING_LAST)
733 (void) synprot_error(L_smtp_protocol_error, 504, NULL,
734 US"zero size for BDAT command");
735 goto repeat_until_rset;
738 bdat_push_receive_functions();
740 dkim_collect_input = dkim_save;
742 break; /* to top of main loop */
749 bdat_getbuf(unsigned * len)
753 if (chunking_data_left <= 0)
754 { *len = 0; return NULL; }
756 if (*len > chunking_data_left) *len = chunking_data_left;
757 buf = lwr_receive_getbuf(len); /* Either smtp_getbuf or tls_getbuf */
758 chunking_data_left -= *len;
763 bdat_flush_data(void)
765 while (chunking_data_left)
767 unsigned n = chunking_data_left;
768 if (!bdat_getbuf(&n)) break;
771 bdat_pop_receive_functions();
773 if (chunking_state != CHUNKING_LAST)
775 chunking_state = CHUNKING_OFFERED;
776 DEBUG(D_receive) debug_printf("chunking state %d\n", (int)chunking_state);
782 bdat_push_receive_functions(void)
784 /* push the current receive_* function on the "stack", and
785 replace them by bdat_getc(), which in turn will use the lwr_receive_*
786 functions to do the dirty work. */
787 if (lwr_receive_getc == NULL)
789 lwr_receive_getc = receive_getc;
790 lwr_receive_getbuf = receive_getbuf;
791 lwr_receive_ungetc = receive_ungetc;
795 DEBUG(D_receive) debug_printf("chunking double-push receive functions\n");
798 receive_getc = bdat_getc;
799 receive_getbuf = bdat_getbuf;
800 receive_ungetc = bdat_ungetc;
804 bdat_pop_receive_functions(void)
806 if (lwr_receive_getc == NULL)
808 DEBUG(D_receive) debug_printf("chunking double-pop receive functions\n");
811 receive_getc = lwr_receive_getc;
812 receive_getbuf = lwr_receive_getbuf;
813 receive_ungetc = lwr_receive_ungetc;
815 lwr_receive_getc = NULL;
816 lwr_receive_getbuf = NULL;
817 lwr_receive_ungetc = NULL;
820 /*************************************************
821 * SMTP version of ungetc() *
822 *************************************************/
824 /* Puts a character back in the input buffer. Only ever
830 Returns: the character
836 if (smtp_inptr <= smtp_inbuffer)
837 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "buffer underflow in smtp_ungetc");
847 chunking_data_left++;
848 bdat_push_receive_functions(); /* we're not done yet, calling push is safe, because it checks the state before pushing anything */
849 return lwr_receive_ungetc(ch);
854 /*************************************************
855 * SMTP version of feof() *
856 *************************************************/
858 /* Tests for a previous EOF
861 Returns: non-zero if the eof flag is set
873 /*************************************************
874 * SMTP version of ferror() *
875 *************************************************/
877 /* Tests for a previous read error, and returns with errno
878 restored to what it was when the error was detected.
881 Returns: non-zero if the error flag is set
887 errno = smtp_had_error;
888 return smtp_had_error;
893 /*************************************************
894 * Test for characters in the SMTP buffer *
895 *************************************************/
897 /* Used at the end of a message
906 return smtp_inptr < smtp_inend;
911 /*************************************************
912 * Write formatted string to SMTP channel *
913 *************************************************/
915 /* This is a separate function so that we don't have to repeat everything for
916 TLS support or debugging. It is global so that the daemon and the
917 authentication functions can use it. It does not return any error indication,
918 because major problems such as dropped connections won't show up till an output
919 flush for non-TLS connections. The smtp_fflush() function is available for
920 checking that: for convenience, TLS output errors are remembered here so that
921 they are also picked up later by smtp_fflush().
923 This function is exposed to the local_scan API; do not change the signature.
927 more further data expected
928 ... optional arguments
934 smtp_printf(const char *format, BOOL more, ...)
939 smtp_vprintf(format, more, ap);
943 /* This is split off so that verify.c:respond_printf() can, in effect, call
944 smtp_printf(), bearing in mind that in C a vararg function can't directly
945 call another vararg function, only a function which accepts a va_list.
947 This function is exposed to the local_scan API; do not change the signature.
949 /*XXX consider passing caller-info in, for string_vformat-onward */
952 smtp_vprintf(const char *format, BOOL more, va_list ap)
954 gstring gs = { .size = big_buffer_size, .ptr = 0, .s = big_buffer };
957 /* Use taint-unchecked routines for writing into big_buffer, trusting
958 that we'll never expand it. */
960 yield = !! string_vformat(&gs, SVFMT_TAINT_NOCHK, format, ap);
961 string_from_gstring(&gs);
965 uschar *msg_copy, *cr, *end;
966 msg_copy = string_copy(gs.s);
967 end = msg_copy + gs.ptr;
968 while ((cr = Ustrchr(msg_copy, '\r')) != NULL) /* lose CRs */
969 memmove(cr, cr + 1, (end--) - cr);
970 debug_printf("SMTP>> %s", msg_copy);
975 log_write(0, LOG_MAIN|LOG_PANIC, "string too large in smtp_printf()");
976 smtp_closedown(US"Unexpected error");
977 exim_exit(EXIT_FAILURE);
980 /* If this is the first output for a (non-batch) RCPT command, see if all RCPTs
981 have had the same. Note: this code is also present in smtp_respond(). It would
982 be tidier to have it only in one place, but when it was added, it was easier to
983 do it that way, so as not to have to mess with the code for the RCPT command,
984 which sometimes uses smtp_printf() and sometimes smtp_respond(). */
986 if (fl.rcpt_in_progress)
988 if (rcpt_smtp_response == NULL)
989 rcpt_smtp_response = string_copy(big_buffer);
990 else if (fl.rcpt_smtp_response_same &&
991 Ustrcmp(rcpt_smtp_response, big_buffer) != 0)
992 fl.rcpt_smtp_response_same = FALSE;
993 fl.rcpt_in_progress = FALSE;
996 /* Now write the string */
1000 tls_in.active.sock >= 0 ? (tls_write(NULL, gs.s, gs.ptr, more) < 0) :
1002 (fwrite(gs.s, gs.ptr, 1, smtp_out) == 0)
1004 smtp_write_error = -1;
1009 /*************************************************
1010 * Flush SMTP out and check for error *
1011 *************************************************/
1013 /* This function isn't currently used within Exim (it detects errors when it
1014 tries to read the next SMTP input), but is available for use in local_scan().
1015 It flushes the output and checks for errors.
1018 Returns: 0 for no error; -1 after an error
1024 if (tls_in.active.sock < 0 && fflush(smtp_out) != 0) smtp_write_error = -1;
1028 tls_in.active.sock >= 0 ? (tls_write(NULL, NULL, 0, FALSE) < 0) :
1030 (fflush(smtp_out) != 0)
1032 smtp_write_error = -1;
1034 return smtp_write_error;
1039 /*************************************************
1040 * SMTP command read timeout *
1041 *************************************************/
1043 /* Signal handler for timing out incoming SMTP commands. This attempts to
1046 Argument: signal number (SIGALRM)
1051 command_timeout_handler(int sig)
1053 had_command_timeout = sig;
1058 /*************************************************
1059 * SIGTERM received *
1060 *************************************************/
1062 /* Signal handler for handling SIGTERM. Again, try to finish tidily.
1064 Argument: signal number (SIGTERM)
1069 command_sigterm_handler(int sig)
1071 had_command_sigterm = sig;
1077 #ifdef SUPPORT_PROXY
1078 /*************************************************
1079 * Check if host is required proxy host *
1080 *************************************************/
1081 /* The function determines if inbound host will be a regular smtp host
1082 or if it is configured that it must use Proxy Protocol. A local
1090 check_proxy_protocol_host()
1094 if ( sender_host_address
1095 && (rc = verify_check_this_host(CUSS &hosts_proxy, NULL, NULL,
1096 sender_host_address, NULL)) == OK)
1099 debug_printf("Detected proxy protocol configured host\n");
1100 proxy_session = TRUE;
1102 return proxy_session;
1106 /*************************************************
1107 * Read data until newline or end of buffer *
1108 *************************************************/
1109 /* While SMTP is server-speaks-first, TLS is client-speaks-first, so we can't
1110 read an entire buffer and assume there will be nothing past a proxy protocol
1111 header. Our approach normally is to use stdio, but again that relies upon
1112 "STARTTLS\r\n" and a server response before the client starts TLS handshake, or
1113 reading _nothing_ before client TLS handshake. So we don't want to use the
1114 usual buffering reads which may read enough to block TLS starting.
1116 So unfortunately we're down to "read one byte at a time, with a syscall each,
1117 and expect a little overhead", for all proxy-opened connections which are v1,
1118 just to handle the TLS-on-connect case. Since SSL functions wrap the
1119 underlying fd, we can't assume that we can feed them any already-read content.
1121 We need to know where to read to, the max capacity, and we'll read until we
1122 get a CR and one more character. Let the caller scream if it's CR+!LF.
1124 Return the amount read.
1128 swallow_until_crlf(int fd, uschar *base, int already, int capacity)
1130 uschar *to = base + already;
1136 /* For "PROXY UNKNOWN\r\n" we, at time of writing, expect to have read
1137 up through the \r; for the _normal_ case, we haven't yet seen the \r. */
1139 cr = memchr(base, '\r', already);
1142 if ((cr - base) < already - 1)
1144 /* \r and presumed \n already within what we have; probably not
1145 actually proxy protocol, but abort cleanly. */
1148 /* \r is last character read, just need one more. */
1152 while (capacity > 0)
1154 do { ret = read(fd, to, 1); } while (ret == -1 && errno == EINTR && !had_command_timeout);
1166 /* reached end without having room for a final newline, abort */
1171 /*************************************************
1172 * Setup host for proxy protocol *
1173 *************************************************/
1174 /* The function configures the connection based on a header from the
1175 inbound host to use Proxy Protocol. The specification is very exact
1176 so exit with an error if do not find the exact required pieces. This
1177 includes an incorrect number of spaces separating args.
1180 Returns: Boolean success
1184 setup_proxy_protocol_host()
1196 struct { /* TCP/UDP over IPv4, len = 12 */
1202 struct { /* TCP/UDP over IPv6, len = 36 */
1203 uint8_t src_addr[16];
1204 uint8_t dst_addr[16];
1208 struct { /* AF_UNIX sockets, len = 216 */
1209 uschar src_addr[108];
1210 uschar dst_addr[108];
1216 /* Temp variables used in PPv2 address:port parsing */
1218 char tmpip[INET_ADDRSTRLEN];
1219 struct sockaddr_in tmpaddr;
1220 char tmpip6[INET6_ADDRSTRLEN];
1221 struct sockaddr_in6 tmpaddr6;
1223 /* We can't read "all data until end" because while SMTP is
1224 server-speaks-first, the TLS handshake is client-speaks-first, so for
1225 TLS-on-connect ports the proxy protocol header will usually be immediately
1226 followed by a TLS handshake, and with N TLS libraries, we can't reliably
1227 reinject data for reading by those. So instead we first read "enough to be
1228 safely read within the header, and figure out how much more to read".
1229 For v1 we will later read to the end-of-line, for v2 we will read based upon
1232 The v2 sig is 12 octets, and another 4 gets us the length, so we know how much
1233 data is needed total. For v1, where the line looks like:
1234 PROXY TCPn L3src L3dest SrcPort DestPort \r\n
1236 However, for v1 there's also `PROXY UNKNOWN\r\n` which is only 15 octets.
1237 We seem to support that. So, if we read 14 octets then we can tell if we're
1238 v2 or v1. If we're v1, we can continue reading as normal.
1240 If we're v2, we can't slurp up the entire header. We need the length in the
1241 15th & 16th octets, then to read everything after that.
1243 So to safely handle v1 and v2, with client-sent-first supported correctly,
1244 we have to do a minimum of 3 read calls, not 1. Eww.
1247 #define PROXY_INITIAL_READ 14
1248 #define PROXY_V2_HEADER_SIZE 16
1249 #if PROXY_INITIAL_READ > PROXY_V2_HEADER_SIZE
1250 # error Code bug in sizes of data to read for proxy usage
1255 int fd = fileno(smtp_in);
1256 const char v2sig[12] = "\x0D\x0A\x0D\x0A\x00\x0D\x0A\x51\x55\x49\x54\x0A";
1257 uschar * iptype; /* To display debug info */
1258 socklen_t vslen = sizeof(struct timeval);
1261 os_non_restarting_signal(SIGALRM, command_timeout_handler);
1262 ALARM(proxy_protocol_timeout);
1266 /* The inbound host was declared to be a Proxy Protocol host, so
1267 don't do a PEEK into the data, actually slurp up enough to be
1268 "safe". Can't take it all because TLS-on-connect clients follow
1269 immediately with TLS handshake. */
1270 ret = read(fd, &hdr, PROXY_INITIAL_READ);
1272 while (ret == -1 && errno == EINTR && !had_command_timeout);
1277 /* For v2, handle reading the length, and then the rest. */
1278 if ((ret == PROXY_INITIAL_READ) && (memcmp(&hdr.v2, v2sig, sizeof(v2sig)) == 0))
1283 /* First get the length fields. */
1286 retmore = read(fd, (uschar*)&hdr + ret, PROXY_V2_HEADER_SIZE - PROXY_INITIAL_READ);
1287 } while (retmore == -1 && errno == EINTR && !had_command_timeout);
1292 ver = (hdr.v2.ver_cmd & 0xf0) >> 4;
1294 /* May 2014: haproxy combined the version and command into one byte to
1295 allow two full bytes for the length field in order to proxy SSL
1296 connections. SSL Proxy is not supported in this version of Exim, but
1297 must still separate values here. */
1301 DEBUG(D_receive) debug_printf("Invalid Proxy Protocol version: %d\n", ver);
1305 /* The v2 header will always be 16 bytes per the spec. */
1306 size = 16 + ntohs(hdr.v2.len);
1307 DEBUG(D_receive) debug_printf("Detected PROXYv2 header, size %d (limit %d)\n",
1308 size, (int)sizeof(hdr));
1310 /* We should now have 16 octets (PROXY_V2_HEADER_SIZE), and we know the total
1311 amount that we need. Double-check that the size is not unreasonable, then
1313 if (size > sizeof(hdr))
1315 DEBUG(D_receive) debug_printf("PROXYv2 header size unreasonably large; security attack?\n");
1323 retmore = read(fd, (uschar*)&hdr + ret, size-ret);
1324 } while (retmore == -1 && errno == EINTR && !had_command_timeout);
1328 DEBUG(D_receive) debug_printf("PROXYv2: have %d/%d required octets\n", ret, size);
1329 } while (ret < size);
1331 } /* end scope for getting rest of data for v2 */
1333 /* At this point: if PROXYv2, we've read the exact size required for all data;
1334 if PROXYv1 then we've read "less than required for any valid line" and should
1337 if (ret >= 16 && memcmp(&hdr.v2, v2sig, 12) == 0)
1339 uint8_t cmd = (hdr.v2.ver_cmd & 0x0f);
1343 case 0x01: /* PROXY command */
1346 case 0x11: /* TCPv4 address type */
1348 tmpaddr.sin_addr.s_addr = hdr.v2.addr.ip4.src_addr;
1349 inet_ntop(AF_INET, &tmpaddr.sin_addr, CS &tmpip, sizeof(tmpip));
1350 if (!string_is_ip_address(US tmpip, NULL))
1352 DEBUG(D_receive) debug_printf("Invalid %s source IP\n", iptype);
1355 proxy_local_address = sender_host_address;
1356 sender_host_address = string_copy(US tmpip);
1357 tmpport = ntohs(hdr.v2.addr.ip4.src_port);
1358 proxy_local_port = sender_host_port;
1359 sender_host_port = tmpport;
1360 /* Save dest ip/port */
1361 tmpaddr.sin_addr.s_addr = hdr.v2.addr.ip4.dst_addr;
1362 inet_ntop(AF_INET, &tmpaddr.sin_addr, CS &tmpip, sizeof(tmpip));
1363 if (!string_is_ip_address(US tmpip, NULL))
1365 DEBUG(D_receive) debug_printf("Invalid %s dest port\n", iptype);
1368 proxy_external_address = string_copy(US tmpip);
1369 tmpport = ntohs(hdr.v2.addr.ip4.dst_port);
1370 proxy_external_port = tmpport;
1372 case 0x21: /* TCPv6 address type */
1374 memmove(tmpaddr6.sin6_addr.s6_addr, hdr.v2.addr.ip6.src_addr, 16);
1375 inet_ntop(AF_INET6, &tmpaddr6.sin6_addr, CS &tmpip6, sizeof(tmpip6));
1376 if (!string_is_ip_address(US tmpip6, NULL))
1378 DEBUG(D_receive) debug_printf("Invalid %s source IP\n", iptype);
1381 proxy_local_address = sender_host_address;
1382 sender_host_address = string_copy(US tmpip6);
1383 tmpport = ntohs(hdr.v2.addr.ip6.src_port);
1384 proxy_local_port = sender_host_port;
1385 sender_host_port = tmpport;
1386 /* Save dest ip/port */
1387 memmove(tmpaddr6.sin6_addr.s6_addr, hdr.v2.addr.ip6.dst_addr, 16);
1388 inet_ntop(AF_INET6, &tmpaddr6.sin6_addr, CS &tmpip6, sizeof(tmpip6));
1389 if (!string_is_ip_address(US tmpip6, NULL))
1391 DEBUG(D_receive) debug_printf("Invalid %s dest port\n", iptype);
1394 proxy_external_address = string_copy(US tmpip6);
1395 tmpport = ntohs(hdr.v2.addr.ip6.dst_port);
1396 proxy_external_port = tmpport;
1400 debug_printf("Unsupported PROXYv2 connection type: 0x%02x\n",
1404 /* Unsupported protocol, keep local connection address */
1406 case 0x00: /* LOCAL command */
1407 /* Keep local connection address for LOCAL */
1412 debug_printf("Unsupported PROXYv2 command: 0x%x\n", cmd);
1416 else if (ret >= 8 && memcmp(hdr.v1.line, "PROXY", 5) == 0)
1420 uschar *sp; /* Utility variables follow */
1425 /* get the rest of the line */
1426 r2 = swallow_until_crlf(fd, (uschar*)&hdr, ret, sizeof(hdr)-ret);
1431 p = string_copy(hdr.v1.line);
1432 end = memchr(p, '\r', ret - 1);
1434 if (!end || (end == (uschar*)&hdr + ret) || end[1] != '\n')
1436 DEBUG(D_receive) debug_printf("Partial or invalid PROXY header\n");
1439 *end = '\0'; /* Terminate the string */
1440 size = end + 2 - p; /* Skip header + CRLF */
1441 DEBUG(D_receive) debug_printf("Detected PROXYv1 header\n");
1442 DEBUG(D_receive) debug_printf("Bytes read not within PROXY header: %d\n", ret - size);
1443 /* Step through the string looking for the required fields. Ensure
1444 strict adherence to required formatting, exit for any error. */
1446 if (!isspace(*(p++)))
1448 DEBUG(D_receive) debug_printf("Missing space after PROXY command\n");
1451 if (!Ustrncmp(p, CCS"TCP4", 4))
1453 else if (!Ustrncmp(p,CCS"TCP6", 4))
1455 else if (!Ustrncmp(p,CCS"UNKNOWN", 7))
1457 iptype = US"Unknown";
1462 DEBUG(D_receive) debug_printf("Invalid TCP type\n");
1466 p += Ustrlen(iptype);
1467 if (!isspace(*(p++)))
1469 DEBUG(D_receive) debug_printf("Missing space after TCP4/6 command\n");
1472 /* Find the end of the arg */
1473 if ((sp = Ustrchr(p, ' ')) == NULL)
1476 debug_printf("Did not find proxied src %s\n", iptype);
1480 if(!string_is_ip_address(p, NULL))
1483 debug_printf("Proxied src arg is not an %s address\n", iptype);
1486 proxy_local_address = sender_host_address;
1487 sender_host_address = p;
1489 if ((sp = Ustrchr(p, ' ')) == NULL)
1492 debug_printf("Did not find proxy dest %s\n", iptype);
1496 if(!string_is_ip_address(p, NULL))
1499 debug_printf("Proxy dest arg is not an %s address\n", iptype);
1502 proxy_external_address = p;
1504 if ((sp = Ustrchr(p, ' ')) == NULL)
1506 DEBUG(D_receive) debug_printf("Did not find proxied src port\n");
1510 tmp_port = strtol(CCS p, &endc, 10);
1511 if (*endc || tmp_port == 0)
1514 debug_printf("Proxied src port '%s' not an integer\n", p);
1517 proxy_local_port = sender_host_port;
1518 sender_host_port = tmp_port;
1520 if ((sp = Ustrchr(p, '\0')) == NULL)
1522 DEBUG(D_receive) debug_printf("Did not find proxy dest port\n");
1525 tmp_port = strtol(CCS p, &endc, 10);
1526 if (*endc || tmp_port == 0)
1529 debug_printf("Proxy dest port '%s' not an integer\n", p);
1532 proxy_external_port = tmp_port;
1533 /* Already checked for /r /n above. Good V1 header received. */
1537 /* Wrong protocol */
1538 DEBUG(D_receive) debug_printf("Invalid proxy protocol version negotiation\n");
1539 (void) swallow_until_crlf(fd, (uschar*)&hdr, ret, sizeof(hdr)-ret);
1545 debug_printf("Valid %s sender from Proxy Protocol header\n", iptype);
1546 yield = proxy_session;
1548 /* Don't flush any potential buffer contents. Any input on proxyfail
1549 should cause a synchronization failure */
1552 DEBUG(D_receive) if (had_command_timeout)
1553 debug_printf("Timeout while reading proxy header\n");
1558 sender_host_name = NULL;
1559 (void) host_name_lookup();
1560 host_build_sender_fullhost();
1564 f.proxy_session_failed = TRUE;
1566 debug_printf("Failure to extract proxied host, only QUIT allowed\n");
1574 /*************************************************
1575 * Read one command line *
1576 *************************************************/
1578 /* Strictly, SMTP commands coming over the net are supposed to end with CRLF.
1579 There are sites that don't do this, and in any case internal SMTP probably
1580 should check only for LF. Consequently, we check here for LF only. The line
1581 ends up with [CR]LF removed from its end. If we get an overlong line, treat as
1582 an unknown command. The command is read into the global smtp_cmd_buffer so that
1583 it is available via $smtp_command.
1585 The character reading routine sets up a timeout for each block actually read
1586 from the input (which may contain more than one command). We set up a special
1587 signal handler that closes down the session on a timeout. Control does not
1588 return when it runs.
1591 check_sync if TRUE, check synchronization rules if global option is TRUE
1592 buffer_lim maximum to buffer in lower layer
1594 Returns: a code identifying the command (enumerated above)
1598 smtp_read_command(BOOL check_sync, unsigned buffer_lim)
1602 BOOL hadnull = FALSE;
1604 had_command_timeout = 0;
1605 os_non_restarting_signal(SIGALRM, command_timeout_handler);
1607 while ((c = (receive_getc)(buffer_lim)) != '\n' && c != EOF)
1609 if (ptr >= SMTP_CMD_BUFFER_SIZE)
1611 os_non_restarting_signal(SIGALRM, sigalrm_handler);
1619 smtp_cmd_buffer[ptr++] = c;
1622 receive_linecount++; /* For BSMTP errors */
1623 os_non_restarting_signal(SIGALRM, sigalrm_handler);
1625 /* If hit end of file, return pseudo EOF command. Whether we have a
1626 part-line already read doesn't matter, since this is an error state. */
1628 if (c == EOF) return EOF_CMD;
1630 /* Remove any CR and white space at the end of the line, and terminate the
1633 while (ptr > 0 && isspace(smtp_cmd_buffer[ptr-1])) ptr--;
1634 smtp_cmd_buffer[ptr] = 0;
1636 DEBUG(D_receive) debug_printf("SMTP<< %s\n", smtp_cmd_buffer);
1638 /* NULLs are not allowed in SMTP commands */
1640 if (hadnull) return BADCHAR_CMD;
1642 /* Scan command list and return identity, having set the data pointer
1643 to the start of the actual data characters. Check for SMTP synchronization
1646 for (smtp_cmd_list * p = cmd_list; p < cmd_list_end; p++)
1648 #ifdef SUPPORT_PROXY
1649 /* Only allow QUIT command if Proxy Protocol parsing failed */
1650 if (proxy_session && f.proxy_session_failed && p->cmd != QUIT_CMD)
1654 && strncmpic(smtp_cmd_buffer, US p->name, p->len) == 0
1655 && ( smtp_cmd_buffer[p->len-1] == ':' /* "mail from:" or "rcpt to:" */
1656 || smtp_cmd_buffer[p->len] == 0
1657 || smtp_cmd_buffer[p->len] == ' '
1660 if (smtp_inptr < smtp_inend && /* Outstanding input */
1661 p->cmd < sync_cmd_limit && /* Command should sync */
1662 check_sync && /* Local flag set */
1663 smtp_enforce_sync && /* Global flag set */
1664 sender_host_address != NULL && /* Not local input */
1665 !f.sender_host_notsocket) /* Really is a socket */
1668 /* The variables $smtp_command and $smtp_command_argument point into the
1669 unmodified input buffer. A copy of the latter is taken for actual
1670 processing, so that it can be chopped up into separate parts if necessary,
1671 for example, when processing a MAIL command options such as SIZE that can
1672 follow the sender address. */
1674 smtp_cmd_argument = smtp_cmd_buffer + p->len;
1675 while (isspace(*smtp_cmd_argument)) smtp_cmd_argument++;
1676 Ustrcpy(smtp_data_buffer, smtp_cmd_argument);
1677 smtp_cmd_data = smtp_data_buffer;
1679 /* Count non-mail commands from those hosts that are controlled in this
1680 way. The default is all hosts. We don't waste effort checking the list
1681 until we get a non-mail command, but then cache the result to save checking
1682 again. If there's a DEFER while checking the host, assume it's in the list.
1684 Note that one instance of RSET, EHLO/HELO, and STARTTLS is allowed at the
1685 start of each incoming message by fiddling with the value in the table. */
1687 if (!p->is_mail_cmd)
1689 if (count_nonmail == TRUE_UNSET) count_nonmail =
1690 verify_check_host(&smtp_accept_max_nonmail_hosts) != FAIL;
1691 if (count_nonmail && ++nonmail_command_count > smtp_accept_max_nonmail)
1692 return TOO_MANY_NONMAIL_CMD;
1695 /* If there is data for a command that does not expect it, generate the
1698 return (p->has_arg || *smtp_cmd_data == 0)? p->cmd : BADARG_CMD;
1702 #ifdef SUPPORT_PROXY
1703 /* Only allow QUIT command if Proxy Protocol parsing failed */
1704 if (proxy_session && f.proxy_session_failed)
1705 return PROXY_FAIL_IGNORE_CMD;
1708 /* Enforce synchronization for unknown commands */
1710 if ( smtp_inptr < smtp_inend /* Outstanding input */
1711 && check_sync /* Local flag set */
1712 && smtp_enforce_sync /* Global flag set */
1713 && sender_host_address /* Not local input */
1714 && !f.sender_host_notsocket) /* Really is a socket */
1722 /*************************************************
1723 * Forced closedown of call *
1724 *************************************************/
1726 /* This function is called from log.c when Exim is dying because of a serious
1727 disaster, and also from some other places. If an incoming non-batched SMTP
1728 channel is open, it swallows the rest of the incoming message if in the DATA
1729 phase, sends the reply string, and gives an error to all subsequent commands
1730 except QUIT. The existence of an SMTP call is detected by the non-NULLness of
1734 message SMTP reply string to send, excluding the code
1740 smtp_closedown(uschar *message)
1742 if (!smtp_in || smtp_batched_input) return;
1743 receive_swallow_smtp();
1744 smtp_printf("421 %s\r\n", FALSE, message);
1746 for (;;) switch(smtp_read_command(FALSE, GETC_BUFFER_UNLIMITED))
1752 f.smtp_in_quit = TRUE;
1753 smtp_printf("221 %s closing connection\r\n", FALSE, smtp_active_hostname);
1758 smtp_printf("250 Reset OK\r\n", FALSE);
1762 smtp_printf("421 %s\r\n", FALSE, message);
1770 /*************************************************
1771 * Set up connection info for logging *
1772 *************************************************/
1774 /* This function is called when logging information about an SMTP connection.
1775 It sets up appropriate source information, depending on the type of connection.
1776 If sender_fullhost is NULL, we are at a very early stage of the connection;
1777 just use the IP address.
1780 Returns: a string describing the connection
1784 smtp_get_connection_info(void)
1786 const uschar * hostname = sender_fullhost
1787 ? sender_fullhost : sender_host_address;
1790 return string_sprintf("SMTP connection from %s", hostname);
1792 if (f.sender_host_unknown || f.sender_host_notsocket)
1793 return string_sprintf("SMTP connection from %s", sender_ident);
1796 return string_sprintf("SMTP connection from %s (via inetd)", hostname);
1798 if (LOGGING(incoming_interface) && interface_address)
1799 return string_sprintf("SMTP connection from %s I=[%s]:%d", hostname,
1800 interface_address, interface_port);
1802 return string_sprintf("SMTP connection from %s", hostname);
1808 /* Append TLS-related information to a log line
1811 g String under construction: allocated string to extend, or NULL
1813 Returns: Allocated string or NULL
1816 s_tlslog(gstring * g)
1818 if (LOGGING(tls_cipher) && tls_in.cipher)
1820 g = string_append(g, 2, US" X=", tls_in.cipher);
1821 #ifndef DISABLE_TLS_RESUME
1822 if (LOGGING(tls_resumption) && tls_in.resumption & RESUME_USED)
1823 g = string_catn(g, US"*", 1);
1826 if (LOGGING(tls_certificate_verified) && tls_in.cipher)
1827 g = string_append(g, 2, US" CV=", tls_in.certificate_verified? "yes":"no");
1828 if (LOGGING(tls_peerdn) && tls_in.peerdn)
1829 g = string_append(g, 3, US" DN=\"", string_printing(tls_in.peerdn), US"\"");
1830 if (LOGGING(tls_sni) && tls_in.sni)
1831 g = string_append(g, 2, US" SNI=", string_printing2(tls_in.sni, SP_TAB|SP_SPACE));
1839 s_connhad_log(gstring * g)
1841 const uschar * sep = smtp_connection_had[SMTP_HBUFF_SIZE-1] != SCH_NONE
1842 ? US" C=..." : US" C=";
1844 for (int i = smtp_ch_index; i < SMTP_HBUFF_SIZE; i++)
1845 if (smtp_connection_had[i] != SCH_NONE)
1847 g = string_append(g, 2, sep, smtp_names[smtp_connection_had[i]]);
1850 for (int i = 0; i < smtp_ch_index; i++, sep = US",")
1851 g = string_append(g, 2, sep, smtp_names[smtp_connection_had[i]]);
1856 /*************************************************
1857 * Log lack of MAIL if so configured *
1858 *************************************************/
1860 /* This function is called when an SMTP session ends. If the log selector
1861 smtp_no_mail is set, write a log line giving some details of what has happened
1862 in the SMTP session.
1869 smtp_log_no_mail(void)
1874 if (smtp_mailcmd_count > 0 || !LOGGING(smtp_no_mail))
1877 if (sender_host_authenticated)
1879 g = string_append(g, 2, US" A=", sender_host_authenticated);
1880 if (authenticated_id) g = string_append(g, 2, US":", authenticated_id);
1887 g = s_connhad_log(g);
1889 if (!(s = string_from_gstring(g))) s = US"";
1891 log_write(0, LOG_MAIN, "no MAIL in %sSMTP connection from %s D=%s%s",
1892 f.tcp_in_fastopen ? f.tcp_in_fastopen_data ? US"TFO* " : US"TFO " : US"",
1893 host_and_ident(FALSE), string_timesince(&smtp_connection_start), s);
1897 /* Return list of recent smtp commands */
1902 gstring * list = NULL;
1905 for (int i = smtp_ch_index; i < SMTP_HBUFF_SIZE; i++)
1906 if (smtp_connection_had[i] != SCH_NONE)
1907 list = string_append_listele(list, ',', smtp_names[smtp_connection_had[i]]);
1909 for (int i = 0; i < smtp_ch_index; i++)
1910 list = string_append_listele(list, ',', smtp_names[smtp_connection_had[i]]);
1912 s = string_from_gstring(list);
1913 return s ? s : US"";
1919 /*************************************************
1920 * Check HELO line and set sender_helo_name *
1921 *************************************************/
1923 /* Check the format of a HELO line. The data for HELO/EHLO is supposed to be
1924 the domain name of the sending host, or an ip literal in square brackets. The
1925 argument is placed in sender_helo_name, which is in malloc store, because it
1926 must persist over multiple incoming messages. If helo_accept_junk is set, this
1927 host is permitted to send any old junk (needed for some broken hosts).
1928 Otherwise, helo_allow_chars can be used for rogue characters in general
1929 (typically people want to let in underscores).
1932 s the data portion of the line (already past any white space)
1934 Returns: TRUE or FALSE
1938 check_helo(uschar *s)
1941 uschar *end = s + Ustrlen(s);
1942 BOOL yield = fl.helo_accept_junk;
1944 /* Discard any previous helo name */
1946 sender_helo_name = NULL;
1948 /* Skip tests if junk is permitted. */
1952 /* Allow the new standard form for IPv6 address literals, namely,
1953 [IPv6:....], and because someone is bound to use it, allow an equivalent
1954 IPv4 form. Allow plain addresses as well. */
1961 if (strncmpic(s, US"[IPv6:", 6) == 0)
1962 yield = (string_is_ip_address(s+6, NULL) == 6);
1963 else if (strncmpic(s, US"[IPv4:", 6) == 0)
1964 yield = (string_is_ip_address(s+6, NULL) == 4);
1966 yield = (string_is_ip_address(s+1, NULL) != 0);
1971 /* Non-literals must be alpha, dot, hyphen, plus any non-valid chars
1972 that have been configured (usually underscore - sigh). */
1975 for (yield = TRUE; *s; s++)
1976 if (!isalnum(*s) && *s != '.' && *s != '-' &&
1977 Ustrchr(helo_allow_chars, *s) == NULL)
1983 /* Save argument if OK */
1985 if (yield) sender_helo_name = string_copy_perm(start, TRUE);
1993 /*************************************************
1994 * Extract SMTP command option *
1995 *************************************************/
1997 /* This function picks the next option setting off the end of smtp_cmd_data. It
1998 is called for MAIL FROM and RCPT TO commands, to pick off the optional ESMTP
1999 things that can appear there.
2002 name point this at the name
2003 value point this at the data string
2005 Returns: TRUE if found an option
2009 extract_option(uschar **name, uschar **value)
2013 if (Ustrlen(smtp_cmd_data) <= 0) return FALSE;
2014 v = smtp_cmd_data + Ustrlen(smtp_cmd_data) - 1;
2015 while (v > smtp_cmd_data && isspace(*v)) v--;
2018 while (v > smtp_cmd_data && *v != '=' && !isspace(*v))
2020 /* Take care to not stop at a space embedded in a quoted local-part */
2023 do v--; while (v > smtp_cmd_data && *v != '"');
2024 if (v <= smtp_cmd_data) return FALSE;
2028 if (v <= smtp_cmd_data) return FALSE;
2033 while (n > smtp_cmd_data && isalpha(n[-1])) n--;
2034 /* RFC says SP, but TAB seen in wild and other major MTAs accept it */
2035 if (n <= smtp_cmd_data || !isspace(n[-1])) return FALSE;
2052 /*************************************************
2053 * Reset for new message *
2054 *************************************************/
2056 /* This function is called whenever the SMTP session is reset from
2057 within either of the setup functions; also from the daemon loop.
2059 Argument: the stacking pool storage reset point
2064 smtp_reset(void *reset_point)
2066 recipients_list = NULL;
2067 rcpt_count = rcpt_defer_count = rcpt_fail_count =
2068 raw_recipients_count = recipients_count = recipients_list_max = 0;
2069 message_linecount = 0;
2071 message_body = message_body_end = NULL;
2072 acl_added_headers = NULL;
2073 acl_removed_headers = NULL;
2074 f.queue_only_policy = FALSE;
2075 rcpt_smtp_response = NULL;
2076 fl.rcpt_smtp_response_same = TRUE;
2077 fl.rcpt_in_progress = FALSE;
2078 f.deliver_freeze = FALSE; /* Can be set by ACL */
2079 freeze_tell = freeze_tell_config; /* Can be set by ACL */
2080 fake_response = OK; /* Can be set by ACL */
2081 #ifdef WITH_CONTENT_SCAN
2082 f.no_mbox_unspool = FALSE; /* Can be set by ACL */
2084 f.submission_mode = FALSE; /* Can be set by ACL */
2085 f.suppress_local_fixups = f.suppress_local_fixups_default; /* Can be set by ACL */
2086 f.active_local_from_check = local_from_check; /* Can be set by ACL */
2087 f.active_local_sender_retain = local_sender_retain; /* Can be set by ACL */
2088 sending_ip_address = NULL;
2089 return_path = sender_address = NULL;
2090 deliver_localpart_data = deliver_domain_data =
2091 recipient_data = sender_data = NULL; /* Can be set by ACL */
2092 recipient_verify_failure = NULL;
2093 deliver_localpart_parent = deliver_localpart_orig = NULL;
2094 deliver_domain_parent = deliver_domain_orig = NULL;
2095 callout_address = NULL;
2096 submission_name = NULL; /* Can be set by ACL */
2097 raw_sender = NULL; /* After SMTP rewrite, before qualifying */
2098 sender_address_unrewritten = NULL; /* Set only after verify rewrite */
2099 sender_verified_list = NULL; /* No senders verified */
2100 memset(sender_address_cache, 0, sizeof(sender_address_cache));
2101 memset(sender_domain_cache, 0, sizeof(sender_domain_cache));
2103 authenticated_sender = NULL;
2104 #ifdef EXPERIMENTAL_BRIGHTMAIL
2106 bmi_verdicts = NULL;
2108 dnslist_domain = dnslist_matched = NULL;
2110 spf_header_comment = spf_received = spf_result = spf_smtp_comment = NULL;
2111 spf_result_guessed = FALSE;
2113 #ifndef DISABLE_DKIM
2114 dkim_cur_signer = dkim_signers =
2115 dkim_signing_domain = dkim_signing_selector = dkim_signatures = NULL;
2116 dkim_cur_signer = dkim_signers = dkim_signing_domain = dkim_signing_selector = NULL;
2117 f.dkim_disable_verify = FALSE;
2118 dkim_collect_input = 0;
2119 dkim_verify_overall = dkim_verify_status = dkim_verify_reason = NULL;
2120 dkim_key_length = 0;
2122 #ifdef SUPPORT_DMARC
2123 f.dmarc_has_been_checked = f.dmarc_disable_verify = f.dmarc_enable_forensic = FALSE;
2124 dmarc_domain_policy = dmarc_status = dmarc_status_text =
2125 dmarc_used_domain = NULL;
2127 #ifdef EXPERIMENTAL_ARC
2128 arc_state = arc_state_reason = NULL;
2129 arc_received_instance = 0;
2133 deliver_host = deliver_host_address = NULL; /* Can be set by ACL */
2134 #ifndef DISABLE_PRDR
2135 prdr_requested = FALSE;
2138 message_smtputf8 = FALSE;
2140 body_linecount = body_zerocount = 0;
2142 sender_rate = sender_rate_limit = sender_rate_period = NULL;
2143 ratelimiters_mail = NULL; /* Updated by ratelimit ACL condition */
2144 /* Note that ratelimiters_conn persists across resets. */
2146 /* Reset message ACL variables */
2150 /* Warning log messages are saved in malloc store. They are saved to avoid
2151 repetition in the same message, but it seems right to repeat them for different
2154 while (acl_warn_logged)
2156 string_item *this = acl_warn_logged;
2157 acl_warn_logged = acl_warn_logged->next;
2162 store_reset(reset_point);
2165 return store_mark();
2172 /*************************************************
2173 * Initialize for incoming batched SMTP message *
2174 *************************************************/
2176 /* This function is called from smtp_setup_msg() in the case when
2177 smtp_batched_input is true. This happens when -bS is used to pass a whole batch
2178 of messages in one file with SMTP commands between them. All errors must be
2179 reported by sending a message, and only MAIL FROM, RCPT TO, and DATA are
2180 relevant. After an error on a sender, or an invalid recipient, the remainder
2181 of the message is skipped. The value of received_protocol is already set.
2184 Returns: > 0 message successfully started (reached DATA)
2185 = 0 QUIT read or end of file reached
2186 < 0 should not occur
2190 smtp_setup_batch_msg(void)
2193 rmark reset_point = store_mark();
2195 /* Save the line count at the start of each transaction - single commands
2196 like HELO and RSET count as whole transactions. */
2198 bsmtp_transaction_linecount = receive_linecount;
2200 if ((receive_feof)()) return 0; /* Treat EOF as QUIT */
2202 cancel_cutthrough_connection(TRUE, US"smtp_setup_batch_msg");
2203 reset_point = smtp_reset(reset_point); /* Reset for start of message */
2205 /* Deal with SMTP commands. This loop is exited by setting done to a POSITIVE
2206 value. The values are 2 larger than the required yield of the function. */
2211 uschar *recipient = NULL;
2212 int start, end, sender_domain, recipient_domain;
2214 switch(smtp_read_command(FALSE, GETC_BUFFER_UNLIMITED))
2216 /* The HELO/EHLO commands set sender_address_helo if they have
2217 valid data; otherwise they are ignored, except that they do
2218 a reset of the state. */
2223 check_helo(smtp_cmd_data);
2227 cancel_cutthrough_connection(TRUE, US"RSET received");
2228 reset_point = smtp_reset(reset_point);
2229 bsmtp_transaction_linecount = receive_linecount;
2233 /* The MAIL FROM command requires an address as an operand. All we
2234 do here is to parse it for syntactic correctness. The form "<>" is
2235 a special case which converts into an empty string. The start/end
2236 pointers in the original are not used further for this address, as
2237 it is the canonical extracted address which is all that is kept. */
2240 smtp_mailcmd_count++; /* Count for no-mail log */
2242 /* The function moan_smtp_batch() does not return. */
2243 moan_smtp_batch(smtp_cmd_buffer, "503 Sender already given");
2245 if (smtp_cmd_data[0] == 0)
2246 /* The function moan_smtp_batch() does not return. */
2247 moan_smtp_batch(smtp_cmd_buffer, "501 MAIL FROM must have an address operand");
2249 /* Reset to start of message */
2251 cancel_cutthrough_connection(TRUE, US"MAIL received");
2252 reset_point = smtp_reset(reset_point);
2254 /* Apply SMTP rewrite */
2256 raw_sender = rewrite_existflags & rewrite_smtp
2257 /* deconst ok as smtp_cmd_data was not const */
2258 ? US rewrite_one(smtp_cmd_data, rewrite_smtp|rewrite_smtp_sender, NULL,
2259 FALSE, US"", global_rewrite_rules)
2262 /* Extract the address; the TRUE flag allows <> as valid */
2265 parse_extract_address(raw_sender, &errmess, &start, &end, &sender_domain,
2269 /* The function moan_smtp_batch() does not return. */
2270 moan_smtp_batch(smtp_cmd_buffer, "501 %s", errmess);
2272 sender_address = string_copy(raw_sender);
2274 /* Qualify unqualified sender addresses if permitted to do so. */
2277 && sender_address[0] != 0 && sender_address[0] != '@')
2278 if (f.allow_unqualified_sender)
2280 /* deconst ok as sender_address was not const */
2281 sender_address = US rewrite_address_qualify(sender_address, FALSE);
2282 DEBUG(D_receive) debug_printf("unqualified address %s accepted "
2283 "and rewritten\n", raw_sender);
2285 /* The function moan_smtp_batch() does not return. */
2287 moan_smtp_batch(smtp_cmd_buffer, "501 sender address must contain "
2292 /* The RCPT TO command requires an address as an operand. All we do
2293 here is to parse it for syntactic correctness. There may be any number
2294 of RCPT TO commands, specifying multiple senders. We build them all into
2295 a data structure that is in argc/argv format. The start/end values
2296 given by parse_extract_address are not used, as we keep only the
2297 extracted address. */
2300 if (!sender_address)
2301 /* The function moan_smtp_batch() does not return. */
2302 moan_smtp_batch(smtp_cmd_buffer, "503 No sender yet given");
2304 if (smtp_cmd_data[0] == 0)
2305 /* The function moan_smtp_batch() does not return. */
2306 moan_smtp_batch(smtp_cmd_buffer,
2307 "501 RCPT TO must have an address operand");
2309 /* Check maximum number allowed */
2311 if (recipients_max > 0 && recipients_count + 1 > recipients_max)
2312 /* The function moan_smtp_batch() does not return. */
2313 moan_smtp_batch(smtp_cmd_buffer, "%s too many recipients",
2314 recipients_max_reject? "552": "452");
2316 /* Apply SMTP rewrite, then extract address. Don't allow "<>" as a
2317 recipient address */
2319 recipient = rewrite_existflags & rewrite_smtp
2320 /* deconst ok as smtp_cmd_data was not const */
2321 ? US rewrite_one(smtp_cmd_data, rewrite_smtp, NULL, FALSE, US"",
2322 global_rewrite_rules)
2325 recipient = parse_extract_address(recipient, &errmess, &start, &end,
2326 &recipient_domain, FALSE);
2329 /* The function moan_smtp_batch() does not return. */
2330 moan_smtp_batch(smtp_cmd_buffer, "501 %s", errmess);
2332 /* If the recipient address is unqualified, qualify it if permitted. Then
2333 add it to the list of recipients. */
2335 if (!recipient_domain)
2336 if (f.allow_unqualified_recipient)
2338 DEBUG(D_receive) debug_printf("unqualified address %s accepted\n",
2340 /* deconst ok as recipient was not const */
2341 recipient = US rewrite_address_qualify(recipient, TRUE);
2343 /* The function moan_smtp_batch() does not return. */
2345 moan_smtp_batch(smtp_cmd_buffer,
2346 "501 recipient address must contain a domain");
2348 receive_add_recipient(recipient, -1);
2352 /* The DATA command is legal only if it follows successful MAIL FROM
2353 and RCPT TO commands. This function is complete when a valid DATA
2354 command is encountered. */
2357 if (!sender_address || recipients_count <= 0)
2358 /* The function moan_smtp_batch() does not return. */
2359 if (!sender_address)
2360 moan_smtp_batch(smtp_cmd_buffer,
2361 "503 MAIL FROM:<sender> command must precede DATA");
2363 moan_smtp_batch(smtp_cmd_buffer,
2364 "503 RCPT TO:<recipient> must precede DATA");
2367 done = 3; /* DATA successfully achieved */
2368 message_ended = END_NOTENDED; /* Indicate in middle of message */
2373 /* The VRFY, EXPN, HELP, ETRN, and NOOP commands are ignored. */
2380 bsmtp_transaction_linecount = receive_linecount;
2385 f.smtp_in_quit = TRUE;
2392 /* The function moan_smtp_batch() does not return. */
2393 moan_smtp_batch(smtp_cmd_buffer, "501 Unexpected argument data");
2398 /* The function moan_smtp_batch() does not return. */
2399 moan_smtp_batch(smtp_cmd_buffer, "501 Unexpected NULL in SMTP command");
2404 /* The function moan_smtp_batch() does not return. */
2405 moan_smtp_batch(smtp_cmd_buffer, "500 Command unrecognized");
2410 return done - 2; /* Convert yield values */
2418 smtp_log_tls_fail(uschar * errstr)
2420 uschar * conn_info = smtp_get_connection_info();
2422 if (Ustrncmp(conn_info, US"SMTP ", 5) == 0) conn_info += 5;
2423 /* I'd like to get separated H= here, but too hard for now */
2425 log_write(0, LOG_MAIN, "TLS error on %s %s", conn_info, errstr);
2439 socklen_t len = sizeof(is_fastopen);
2441 /* The tinfo TCPOPT_FAST_OPEN bit seems unreliable, and we don't see state
2442 TCP_SYN_RCV (as of 12.1) so no idea about data-use. */
2444 if (getsockopt(fileno(smtp_out), IPPROTO_TCP, TCP_FASTOPEN, &is_fastopen, &len) == 0)
2449 debug_printf("TFO mode connection (TCP_FASTOPEN getsockopt)\n");
2450 f.tcp_in_fastopen = TRUE;
2453 else DEBUG(D_receive)
2454 debug_printf("TCP_INFO getsockopt: %s\n", strerror(errno));
2456 # elif defined(TCP_INFO)
2457 struct tcp_info tinfo;
2458 socklen_t len = sizeof(tinfo);
2460 if (getsockopt(fileno(smtp_out), IPPROTO_TCP, TCP_INFO, &tinfo, &len) == 0)
2461 # ifdef TCPI_OPT_SYN_DATA /* FreeBSD 11,12 do not seem to have this yet */
2462 if (tinfo.tcpi_options & TCPI_OPT_SYN_DATA)
2465 debug_printf("TFO mode connection (ACKd data-on-SYN)\n");
2466 f.tcp_in_fastopen_data = f.tcp_in_fastopen = TRUE;
2470 if (tinfo.tcpi_state == TCP_SYN_RECV) /* Not seen on FreeBSD 12.1 */
2473 debug_printf("TFO mode connection (state TCP_SYN_RECV)\n");
2474 f.tcp_in_fastopen = TRUE;
2476 else DEBUG(D_receive)
2477 debug_printf("TCP_INFO getsockopt: %s\n", strerror(errno));
2483 /*************************************************
2484 * Start an SMTP session *
2485 *************************************************/
2487 /* This function is called at the start of an SMTP session. Thereafter,
2488 smtp_setup_msg() is called to initiate each separate message. This
2489 function does host-specific testing, and outputs the banner line.
2492 Returns: FALSE if the session can not continue; something has
2493 gone wrong, or the connection to the host is blocked
2497 smtp_start_session(void)
2500 uschar *user_msg, *log_msg;
2505 gettimeofday(&smtp_connection_start, NULL);
2506 for (smtp_ch_index = 0; smtp_ch_index < SMTP_HBUFF_SIZE; smtp_ch_index++)
2507 smtp_connection_had[smtp_ch_index] = SCH_NONE;
2510 /* Default values for certain variables */
2512 fl.helo_seen = fl.esmtp = fl.helo_accept_junk = FALSE;
2513 smtp_mailcmd_count = 0;
2514 count_nonmail = TRUE_UNSET;
2515 synprot_error_count = unknown_command_count = nonmail_command_count = 0;
2516 smtp_delay_mail = smtp_rlm_base;
2517 fl.auth_advertised = FALSE;
2518 f.smtp_in_pipelining_advertised = f.smtp_in_pipelining_used = FALSE;
2519 f.pipelining_enable = TRUE;
2520 sync_cmd_limit = NON_SYNC_CMD_NON_PIPELINING;
2521 fl.smtp_exit_function_called = FALSE; /* For avoiding loop in not-quit exit */
2523 /* If receiving by -bs from a trusted user, or testing with -bh, we allow
2524 authentication settings from -oMaa to remain in force. */
2526 if (!host_checking && !f.sender_host_notsocket)
2527 sender_host_auth_pubname = sender_host_authenticated = NULL;
2528 authenticated_by = NULL;
2531 tls_in.ver = tls_in.cipher = tls_in.peerdn = NULL;
2532 tls_in.ourcert = tls_in.peercert = NULL;
2534 tls_in.ocsp = OCSP_NOT_REQ;
2535 fl.tls_advertised = FALSE;
2537 fl.dsn_advertised = FALSE;
2539 fl.smtputf8_advertised = FALSE;
2542 /* Reset ACL connection variables */
2546 /* Allow for trailing 0 in the command and data buffers. Tainted. */
2548 smtp_cmd_buffer = store_get_perm(2*SMTP_CMD_BUFFER_SIZE + 2, TRUE);
2550 smtp_cmd_buffer[0] = 0;
2551 smtp_data_buffer = smtp_cmd_buffer + SMTP_CMD_BUFFER_SIZE + 1;
2553 /* For batched input, the protocol setting can be overridden from the
2554 command line by a trusted caller. */
2556 if (smtp_batched_input)
2558 if (!received_protocol) received_protocol = US"local-bsmtp";
2561 /* For non-batched SMTP input, the protocol setting is forced here. It will be
2562 reset later if any of EHLO/AUTH/STARTTLS are received. */
2566 (sender_host_address ? protocols : protocols_local) [pnormal];
2568 /* Set up the buffer for inputting using direct read() calls, and arrange to
2569 call the local functions instead of the standard C ones. Place a NUL at the
2570 end of the buffer to safety-stop C-string reads from it. */
2572 if (!(smtp_inbuffer = US malloc(IN_BUFFER_SIZE)))
2573 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "malloc() failed for SMTP input buffer");
2574 smtp_inbuffer[IN_BUFFER_SIZE-1] = '\0';
2576 receive_getc = smtp_getc;
2577 receive_getbuf = smtp_getbuf;
2578 receive_get_cache = smtp_get_cache;
2579 receive_ungetc = smtp_ungetc;
2580 receive_feof = smtp_feof;
2581 receive_ferror = smtp_ferror;
2582 receive_smtp_buffered = smtp_buffered;
2583 lwr_receive_getc = NULL;
2584 lwr_receive_getbuf = NULL;
2585 lwr_receive_ungetc = NULL;
2586 smtp_inptr = smtp_inend = smtp_inbuffer;
2587 smtp_had_eof = smtp_had_error = 0;
2589 /* Set up the message size limit; this may be host-specific */
2591 thismessage_size_limit = expand_string_integer(message_size_limit, TRUE);
2592 if (expand_string_message)
2594 if (thismessage_size_limit == -1)
2595 log_write(0, LOG_MAIN|LOG_PANIC, "unable to expand message_size_limit: "
2596 "%s", expand_string_message);
2598 log_write(0, LOG_MAIN|LOG_PANIC, "invalid message_size_limit: "
2599 "%s", expand_string_message);
2600 smtp_closedown(US"Temporary local problem - please try later");
2604 /* When a message is input locally via the -bs or -bS options, sender_host_
2605 unknown is set unless -oMa was used to force an IP address, in which case it
2606 is checked like a real remote connection. When -bs is used from inetd, this
2607 flag is not set, causing the sending host to be checked. The code that deals
2608 with IP source routing (if configured) is never required for -bs or -bS and
2609 the flag sender_host_notsocket is used to suppress it.
2611 If smtp_accept_max and smtp_accept_reserve are set, keep some connections in
2612 reserve for certain hosts and/or networks. */
2614 if (!f.sender_host_unknown)
2617 BOOL reserved_host = FALSE;
2619 /* Look up IP options (source routing info) on the socket if this is not an
2620 -oMa "host", and if any are found, log them and drop the connection.
2622 Linux (and others now, see below) is different to everyone else, so there
2623 has to be some conditional compilation here. Versions of Linux before 2.1.15
2624 used a structure whose name was "options". Somebody finally realized that
2625 this name was silly, and it got changed to "ip_options". I use the
2626 newer name here, but there is a fudge in the script that sets up os.h
2627 to define a macro in older Linux systems.
2629 Sigh. Linux is a fast-moving target. Another generation of Linux uses
2630 glibc 2, which has chosen ip_opts for the structure name. This is now
2631 really a glibc thing rather than a Linux thing, so the condition name
2632 has been changed to reflect this. It is relevant also to GNU/Hurd.
2634 Mac OS 10.x (Darwin) is like the later glibc versions, but without the
2635 setting of the __GLIBC__ macro, so we can't detect it automatically. There's
2636 a special macro defined in the os.h file.
2638 Some DGUX versions on older hardware appear not to support IP options at
2639 all, so there is now a general macro which can be set to cut out this
2642 How to do this properly in IPv6 is not yet known. */
2644 #if !HAVE_IPV6 && !defined(NO_IP_OPTIONS)
2646 #ifdef GLIBC_IP_OPTIONS
2647 #if (!defined __GLIBC__) || (__GLIBC__ < 2)
2652 #elif defined DARWIN_IP_OPTIONS
2658 if (!host_checking && !f.sender_host_notsocket)
2661 EXIM_SOCKLEN_T optlen = sizeof(struct ip_options) + MAX_IPOPTLEN;
2662 struct ip_options *ipopt = store_get(optlen, FALSE);
2664 struct ip_opts ipoptblock;
2665 struct ip_opts *ipopt = &ipoptblock;
2666 EXIM_SOCKLEN_T optlen = sizeof(ipoptblock);
2668 struct ipoption ipoptblock;
2669 struct ipoption *ipopt = &ipoptblock;
2670 EXIM_SOCKLEN_T optlen = sizeof(ipoptblock);
2673 /* Occasional genuine failures of getsockopt() have been seen - for
2674 example, "reset by peer". Therefore, just log and give up on this
2675 call, unless the error is ENOPROTOOPT. This error is given by systems
2676 that have the interfaces but not the mechanism - e.g. GNU/Hurd at the time
2677 of writing. So for that error, carry on - we just can't do an IP options
2680 DEBUG(D_receive) debug_printf("checking for IP options\n");
2682 if (getsockopt(fileno(smtp_out), IPPROTO_IP, IP_OPTIONS, US (ipopt),
2685 if (errno != ENOPROTOOPT)
2687 log_write(0, LOG_MAIN, "getsockopt() failed from %s: %s",
2688 host_and_ident(FALSE), strerror(errno));
2689 smtp_printf("451 SMTP service not available\r\n", FALSE);
2694 /* Deal with any IP options that are set. On the systems I have looked at,
2695 the value of MAX_IPOPTLEN has been 40, meaning that there should never be
2696 more logging data than will fit in big_buffer. Nevertheless, after somebody
2697 questioned this code, I've added in some paranoid checking. */
2699 else if (optlen > 0)
2701 uschar *p = big_buffer;
2702 uschar *pend = big_buffer + big_buffer_size;
2705 struct in_addr addr;
2708 uschar *optstart = US (ipopt->__data);
2710 uschar *optstart = US (ipopt->ip_opts);
2712 uschar *optstart = US (ipopt->ipopt_list);
2715 DEBUG(D_receive) debug_printf("IP options exist\n");
2717 Ustrcpy(p, "IP options on incoming call:");
2720 for (uschar * opt = optstart; opt && opt < US (ipopt) + optlen; )
2733 if (!string_format(p, pend-p, " %s [@%s",
2734 (*opt == IPOPT_SSRR)? "SSRR" : "LSRR",
2736 inet_ntoa(*((struct in_addr *)(&(ipopt->faddr))))))
2738 inet_ntoa(ipopt->ip_dst)))
2740 inet_ntoa(ipopt->ipopt_dst)))
2748 optcount = (opt[1] - 3) / sizeof(struct in_addr);
2750 while (optcount-- > 0)
2752 memcpy(&addr, adptr, sizeof(addr));
2753 if (!string_format(p, pend - p - 1, "%s%s",
2754 (optcount == 0)? ":" : "@", inet_ntoa(addr)))
2760 adptr += sizeof(struct in_addr);
2768 if (pend - p < 4 + 3*opt[1]) { opt = NULL; break; }
2771 for (int i = 0; i < opt[1]; i++)
2772 p += sprintf(CS p, "%2.2x ", opt[i]);
2780 log_write(0, LOG_MAIN, "%s", big_buffer);
2782 /* Refuse any call with IP options. This is what tcpwrappers 7.5 does. */
2784 log_write(0, LOG_MAIN|LOG_REJECT,
2785 "connection from %s refused (IP options)", host_and_ident(FALSE));
2787 smtp_printf("554 SMTP service not available\r\n", FALSE);
2791 /* Length of options = 0 => there are no options */
2793 else DEBUG(D_receive) debug_printf("no IP options found\n");
2795 #endif /* HAVE_IPV6 && !defined(NO_IP_OPTIONS) */
2797 /* Set keep-alive in socket options. The option is on by default. This
2798 setting is an attempt to get rid of some hanging connections that stick in
2799 read() when the remote end (usually a dialup) goes away. */
2801 if (smtp_accept_keepalive && !f.sender_host_notsocket)
2802 ip_keepalive(fileno(smtp_out), sender_host_address, FALSE);
2804 /* If the current host matches host_lookup, set the name by doing a
2805 reverse lookup. On failure, sender_host_name will be NULL and
2806 host_lookup_failed will be TRUE. This may or may not be serious - optional
2809 if (verify_check_host(&host_lookup) == OK)
2811 (void)host_name_lookup();
2812 host_build_sender_fullhost();
2815 /* Delay this until we have the full name, if it is looked up. */
2817 set_process_info("handling incoming connection from %s",
2818 host_and_ident(FALSE));
2820 /* Expand smtp_receive_timeout, if needed */
2822 if (smtp_receive_timeout_s)
2825 if ( !(exp = expand_string(smtp_receive_timeout_s))
2827 || (smtp_receive_timeout = readconf_readtime(exp, 0, FALSE)) < 0
2829 log_write(0, LOG_MAIN|LOG_PANIC,
2830 "bad value for smtp_receive_timeout: '%s'", exp ? exp : US"");
2833 /* Test for explicit connection rejection */
2835 if (verify_check_host(&host_reject_connection) == OK)
2837 log_write(L_connection_reject, LOG_MAIN|LOG_REJECT, "refused connection "
2838 "from %s (host_reject_connection)", host_and_ident(FALSE));
2839 smtp_printf("554 SMTP service not available\r\n", FALSE);
2843 /* Test with TCP Wrappers if so configured. There is a problem in that
2844 hosts_ctl() returns 0 (deny) under a number of system failure circumstances,
2845 such as disks dying. In these cases, it is desirable to reject with a 4xx
2846 error instead of a 5xx error. There isn't a "right" way to detect such
2847 problems. The following kludge is used: errno is zeroed before calling
2848 hosts_ctl(). If the result is "reject", a 5xx error is given only if the
2849 value of errno is 0 or ENOENT (which happens if /etc/hosts.{allow,deny} does
2852 #ifdef USE_TCP_WRAPPERS
2854 if (!(tcp_wrappers_name = expand_string(tcp_wrappers_daemon_name)))
2855 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "Expansion of \"%s\" "
2856 "(tcp_wrappers_name) failed: %s", string_printing(tcp_wrappers_name),
2857 expand_string_message);
2859 if (!hosts_ctl(tcp_wrappers_name,
2860 sender_host_name ? CS sender_host_name : STRING_UNKNOWN,
2861 sender_host_address ? CS sender_host_address : STRING_UNKNOWN,
2862 sender_ident ? CS sender_ident : STRING_UNKNOWN))
2864 if (errno == 0 || errno == ENOENT)
2866 HDEBUG(D_receive) debug_printf("tcp wrappers rejection\n");
2867 log_write(L_connection_reject,
2868 LOG_MAIN|LOG_REJECT, "refused connection from %s "
2869 "(tcp wrappers)", host_and_ident(FALSE));
2870 smtp_printf("554 SMTP service not available\r\n", FALSE);
2874 int save_errno = errno;
2875 HDEBUG(D_receive) debug_printf("tcp wrappers rejected with unexpected "
2876 "errno value %d\n", save_errno);
2877 log_write(L_connection_reject,
2878 LOG_MAIN|LOG_REJECT, "temporarily refused connection from %s "
2879 "(tcp wrappers errno=%d)", host_and_ident(FALSE), save_errno);
2880 smtp_printf("451 Temporary local problem - please try later\r\n", FALSE);
2886 /* Check for reserved slots. The value of smtp_accept_count has already been
2887 incremented to include this process. */
2889 if (smtp_accept_max > 0 &&
2890 smtp_accept_count > smtp_accept_max - smtp_accept_reserve)
2892 if ((rc = verify_check_host(&smtp_reserve_hosts)) != OK)
2894 log_write(L_connection_reject,
2895 LOG_MAIN, "temporarily refused connection from %s: not in "
2896 "reserve list: connected=%d max=%d reserve=%d%s",
2897 host_and_ident(FALSE), smtp_accept_count - 1, smtp_accept_max,
2898 smtp_accept_reserve, (rc == DEFER)? " (lookup deferred)" : "");
2899 smtp_printf("421 %s: Too many concurrent SMTP connections; "
2900 "please try again later\r\n", FALSE, smtp_active_hostname);
2903 reserved_host = TRUE;
2906 /* If a load level above which only messages from reserved hosts are
2907 accepted is set, check the load. For incoming calls via the daemon, the
2908 check is done in the superior process if there are no reserved hosts, to
2909 save a fork. In all cases, the load average will already be available
2910 in a global variable at this point. */
2912 if (smtp_load_reserve >= 0 &&
2913 load_average > smtp_load_reserve &&
2915 verify_check_host(&smtp_reserve_hosts) != OK)
2917 log_write(L_connection_reject,
2918 LOG_MAIN, "temporarily refused connection from %s: not in "
2919 "reserve list and load average = %.2f", host_and_ident(FALSE),
2920 (double)load_average/1000.0);
2921 smtp_printf("421 %s: Too much load; please try again later\r\n", FALSE,
2922 smtp_active_hostname);
2926 /* Determine whether unqualified senders or recipients are permitted
2927 for this host. Unfortunately, we have to do this every time, in order to
2928 set the flags so that they can be inspected when considering qualifying
2929 addresses in the headers. For a site that permits no qualification, this
2930 won't take long, however. */
2932 f.allow_unqualified_sender =
2933 verify_check_host(&sender_unqualified_hosts) == OK;
2935 f.allow_unqualified_recipient =
2936 verify_check_host(&recipient_unqualified_hosts) == OK;
2938 /* Determine whether HELO/EHLO is required for this host. The requirement
2939 can be hard or soft. */
2941 fl.helo_verify_required = verify_check_host(&helo_verify_hosts) == OK;
2942 if (!fl.helo_verify_required)
2943 fl.helo_verify = verify_check_host(&helo_try_verify_hosts) == OK;
2945 /* Determine whether this hosts is permitted to send syntactic junk
2946 after a HELO or EHLO command. */
2948 fl.helo_accept_junk = verify_check_host(&helo_accept_junk_hosts) == OK;
2951 /* For batch SMTP input we are now done. */
2953 if (smtp_batched_input) return TRUE;
2955 /* If valid Proxy Protocol source is connecting, set up session.
2956 Failure will not allow any SMTP function other than QUIT. */
2958 #ifdef SUPPORT_PROXY
2959 proxy_session = FALSE;
2960 f.proxy_session_failed = FALSE;
2961 if (check_proxy_protocol_host())
2962 setup_proxy_protocol_host();
2965 /* Start up TLS if tls_on_connect is set. This is for supporting the legacy
2966 smtps port for use with older style SSL MTAs. */
2969 if (tls_in.on_connect)
2971 if (tls_server_start(&user_msg) != OK)
2972 return smtp_log_tls_fail(user_msg);
2973 cmd_list[CMD_LIST_TLS_AUTH].is_mail_cmd = TRUE;
2977 /* Run the connect ACL if it exists */
2980 if (acl_smtp_connect)
2983 if ((rc = acl_check(ACL_WHERE_CONNECT, NULL, acl_smtp_connect, &user_msg,
2986 (void) smtp_handle_acl_fail(ACL_WHERE_CONNECT, rc, user_msg, log_msg);
2991 /* Output the initial message for a two-way SMTP connection. It may contain
2992 newlines, which then cause a multi-line response to be given. */
2994 code = US"220"; /* Default status code */
2995 esc = US""; /* Default extended status code */
2996 esclen = 0; /* Length of esc */
3000 if (!(s = expand_string(smtp_banner)))
3001 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "Expansion of \"%s\" (smtp_banner) "
3002 "failed: %s", smtp_banner, expand_string_message);
3008 smtp_message_code(&code, &codelen, &s, NULL, TRUE);
3012 esclen = codelen - 4;
3016 /* Remove any terminating newlines; might as well remove trailing space too */
3019 while (p > s && isspace(p[-1])) p--;
3020 s = string_copyn(s, p-s);
3022 /* It seems that CC:Mail is braindead, and assumes that the greeting message
3023 is all contained in a single IP packet. The original code wrote out the
3024 greeting using several calls to fprint/fputc, and on busy servers this could
3025 cause it to be split over more than one packet - which caused CC:Mail to fall
3026 over when it got the second part of the greeting after sending its first
3027 command. Sigh. To try to avoid this, build the complete greeting message
3028 first, and output it in one fell swoop. This gives a better chance of it
3029 ending up as a single packet. */
3031 ss = string_get(256);
3034 do /* At least once, in case we have an empty string */
3037 uschar *linebreak = Ustrchr(p, '\n');
3038 ss = string_catn(ss, code, 3);
3042 ss = string_catn(ss, US" ", 1);
3046 len = linebreak - p;
3047 ss = string_catn(ss, US"-", 1);
3049 ss = string_catn(ss, esc, esclen);
3050 ss = string_catn(ss, p, len);
3051 ss = string_catn(ss, US"\r\n", 2);
3057 /* Before we write the banner, check that there is no input pending, unless
3058 this synchronisation check is disabled. */
3060 #ifndef DISABLE_PIPE_CONNECT
3061 fl.pipe_connect_acceptable =
3062 sender_host_address && verify_check_host(&pipe_connect_advertise_hosts) == OK;
3065 if (fl.pipe_connect_acceptable)
3066 f.smtp_in_early_pipe_used = TRUE;
3072 unsigned n = smtp_inend - smtp_inptr;
3073 if (n > 128) n = 128;
3075 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP protocol "
3076 "synchronization error (input sent without waiting for greeting): "
3077 "rejected connection from %s input=\"%s\"", host_and_ident(TRUE),
3078 string_printing(string_copyn(smtp_inptr, n)));
3079 smtp_printf("554 SMTP synchronization error\r\n", FALSE);
3083 /* Now output the banner */
3084 /*XXX the ehlo-resp code does its own tls/nontls bit. Maybe subroutine that? */
3087 #ifndef DISABLE_PIPE_CONNECT
3088 fl.pipe_connect_acceptable && pipeline_connect_sends(),
3092 string_from_gstring(ss));
3094 /* Attempt to see if we sent the banner before the last ACK of the 3-way
3095 handshake arrived. If so we must have managed a TFO. */
3098 if (sender_host_address && !f.sender_host_notsocket) tfo_in_check();
3108 /*************************************************
3109 * Handle SMTP syntax and protocol errors *
3110 *************************************************/
3112 /* Write to the log for SMTP syntax errors in incoming commands, if configured
3113 to do so. Then transmit the error response. The return value depends on the
3114 number of syntax and protocol errors in this SMTP session.
3117 type error type, given as a log flag bit
3118 code response code; <= 0 means don't send a response
3119 data data to reflect in the response (can be NULL)
3120 errmess the error message
3122 Returns: -1 limit of syntax/protocol errors NOT exceeded
3123 +1 limit of syntax/protocol errors IS exceeded
3125 These values fit in with the values of the "done" variable in the main
3126 processing loop in smtp_setup_msg(). */
3129 synprot_error(int type, int code, uschar *data, uschar *errmess)
3133 log_write(type, LOG_MAIN, "SMTP %s error in \"%s\" %s %s",
3134 type == L_smtp_syntax_error ? "syntax" : "protocol",
3135 string_printing(smtp_cmd_buffer), host_and_ident(TRUE), errmess);
3137 if (++synprot_error_count > smtp_max_synprot_errors)
3140 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
3141 "syntax or protocol errors (last command was \"%s\", %s)",
3142 host_and_ident(FALSE), string_printing(smtp_cmd_buffer),
3143 string_from_gstring(s_connhad_log(NULL))
3149 smtp_printf("%d%c%s%s%s\r\n", FALSE, code, yield == 1 ? '-' : ' ',
3150 data ? data : US"", data ? US": " : US"", errmess);
3152 smtp_printf("%d Too many syntax or protocol errors\r\n", FALSE, code);
3161 /*************************************************
3162 * Send SMTP response, possibly multiline *
3163 *************************************************/
3165 /* There are, it seems, broken clients out there that cannot handle multiline
3166 responses. If no_multiline_responses is TRUE (it can be set from an ACL), we
3167 output nothing for non-final calls, and only the first line for anything else.
3170 code SMTP code, may involve extended status codes
3171 codelen length of smtp code; if > 4 there's an ESC
3172 final FALSE if the last line isn't the final line
3173 msg message text, possibly containing newlines
3179 smtp_respond(uschar* code, int codelen, BOOL final, uschar *msg)
3184 if (!final && f.no_multiline_responses) return;
3189 esclen = codelen - 4;
3192 /* If this is the first output for a (non-batch) RCPT command, see if all RCPTs
3193 have had the same. Note: this code is also present in smtp_printf(). It would
3194 be tidier to have it only in one place, but when it was added, it was easier to
3195 do it that way, so as not to have to mess with the code for the RCPT command,
3196 which sometimes uses smtp_printf() and sometimes smtp_respond(). */
3198 if (fl.rcpt_in_progress)
3200 if (!rcpt_smtp_response)
3201 rcpt_smtp_response = string_copy(msg);
3202 else if (fl.rcpt_smtp_response_same &&
3203 Ustrcmp(rcpt_smtp_response, msg) != 0)
3204 fl.rcpt_smtp_response_same = FALSE;
3205 fl.rcpt_in_progress = FALSE;
3208 /* Now output the message, splitting it up into multiple lines if necessary.
3209 We only handle pipelining these responses as far as nonfinal/final groups,
3210 not the whole MAIL/RCPT/DATA response set. */
3214 uschar *nl = Ustrchr(msg, '\n');
3217 smtp_printf("%.3s%c%.*s%s\r\n", !final, code, final ? ' ':'-', esclen, esc, msg);
3220 else if (nl[1] == 0 || f.no_multiline_responses)
3222 smtp_printf("%.3s%c%.*s%.*s\r\n", !final, code, final ? ' ':'-', esclen, esc,
3223 (int)(nl - msg), msg);
3228 smtp_printf("%.3s-%.*s%.*s\r\n", TRUE, code, esclen, esc, (int)(nl - msg), msg);
3230 Uskip_whitespace(&msg);
3238 /*************************************************
3239 * Parse user SMTP message *
3240 *************************************************/
3242 /* This function allows for user messages overriding the response code details
3243 by providing a suitable response code string at the start of the message
3244 user_msg. Check the message for starting with a response code and optionally an
3245 extended status code. If found, check that the first digit is valid, and if so,
3246 change the code pointer and length to use the replacement. An invalid code
3247 causes a panic log; in this case, if the log messages is the same as the user
3248 message, we must also adjust the value of the log message to show the code that
3249 is actually going to be used (the original one).
3251 This function is global because it is called from receive.c as well as within
3254 Note that the code length returned includes the terminating whitespace
3255 character, which is always included in the regex match.
3258 code SMTP code, may involve extended status codes
3259 codelen length of smtp code; if > 4 there's an ESC
3261 log_msg optional log message, to be adjusted with the new SMTP code
3262 check_valid if true, verify the response code
3268 smtp_message_code(uschar **code, int *codelen, uschar **msg, uschar **log_msg,
3274 if (!msg || !*msg) return;
3276 if ((n = pcre_exec(regex_smtp_code, NULL, CS *msg, Ustrlen(*msg), 0,
3277 PCRE_EOPT, ovector, sizeof(ovector)/sizeof(int))) < 0) return;
3279 if (check_valid && (*msg)[0] != (*code)[0])
3281 log_write(0, LOG_MAIN|LOG_PANIC, "configured error code starts with "
3282 "incorrect digit (expected %c) in \"%s\"", (*code)[0], *msg);
3283 if (log_msg != NULL && *log_msg == *msg)
3284 *log_msg = string_sprintf("%s %s", *code, *log_msg + ovector[1]);
3289 *codelen = ovector[1]; /* Includes final space */
3291 *msg += ovector[1]; /* Chop the code off the message */
3298 /*************************************************
3299 * Handle an ACL failure *
3300 *************************************************/
3302 /* This function is called when acl_check() fails. As well as calls from within
3303 this module, it is called from receive.c for an ACL after DATA. It sorts out
3304 logging the incident, and sends the error response. A message containing
3305 newlines is turned into a multiline SMTP response, but for logging, only the
3308 There's a table of default permanent failure response codes to use in
3309 globals.c, along with the table of names. VFRY is special. Despite RFC1123 it
3310 defaults disabled in Exim. However, discussion in connection with RFC 821bis
3311 (aka RFC 2821) has concluded that the response should be 252 in the disabled
3312 state, because there are broken clients that try VRFY before RCPT. A 5xx
3313 response should be given only when the address is positively known to be
3314 undeliverable. Sigh. We return 252 if there is no VRFY ACL or it provides
3315 no explicit code, but if there is one we let it know best.
3316 Also, for ETRN, 458 is given on refusal, and for AUTH, 503.
3318 From Exim 4.63, it is possible to override the response code details by
3319 providing a suitable response code string at the start of the message provided
3320 in user_msg. The code's first digit is checked for validity.
3323 where where the ACL was called from
3325 user_msg a message that can be included in an SMTP response
3326 log_msg a message for logging
3328 Returns: 0 in most cases
3329 2 if the failure code was FAIL_DROP, in which case the
3330 SMTP connection should be dropped (this value fits with the
3331 "done" variable in smtp_setup_msg() below)
3335 smtp_handle_acl_fail(int where, int rc, uschar *user_msg, uschar *log_msg)
3337 BOOL drop = rc == FAIL_DROP;
3341 uschar *sender_info = US"";
3344 if (drop) rc = FAIL;
3346 /* Set the default SMTP code, and allow a user message to change it. */
3348 smtp_code = rc == FAIL ? acl_wherecodes[where] : US"451";
3349 smtp_message_code(&smtp_code, &codelen, &user_msg, &log_msg,
3350 where != ACL_WHERE_VRFY);
3352 /* We used to have sender_address here; however, there was a bug that was not
3353 updating sender_address after a rewrite during a verify. When this bug was
3354 fixed, sender_address at this point became the rewritten address. I'm not sure
3355 this is what should be logged, so I've changed to logging the unrewritten
3356 address to retain backward compatibility. */
3360 #ifdef WITH_CONTENT_SCAN
3361 case ACL_WHERE_MIME: what = US"during MIME ACL checks"; break;
3363 case ACL_WHERE_PREDATA: what = US"DATA"; break;
3364 case ACL_WHERE_DATA: what = US"after DATA"; break;
3365 #ifndef DISABLE_PRDR
3366 case ACL_WHERE_PRDR: what = US"after DATA PRDR"; break;
3370 uschar * place = smtp_cmd_data ? smtp_cmd_data : US"in \"connect\" ACL";
3373 if (where == ACL_WHERE_AUTH) /* avoid logging auth creds */
3376 for (s = smtp_cmd_data; *s && !isspace(*s); ) s++;
3377 lim = s - smtp_cmd_data; /* atop after method */
3379 what = string_sprintf("%s %.*s", acl_wherenames[where], lim, place);
3384 case ACL_WHERE_RCPT:
3385 case ACL_WHERE_DATA:
3386 #ifdef WITH_CONTENT_SCAN
3387 case ACL_WHERE_MIME:
3389 sender_info = string_sprintf("F=<%s>%s%s%s%s ",
3390 sender_address_unrewritten ? sender_address_unrewritten : sender_address,
3391 sender_host_authenticated ? US" A=" : US"",
3392 sender_host_authenticated ? sender_host_authenticated : US"",
3393 sender_host_authenticated && authenticated_id ? US":" : US"",
3394 sender_host_authenticated && authenticated_id ? authenticated_id : US""
3399 /* If there's been a sender verification failure with a specific message, and
3400 we have not sent a response about it yet, do so now, as a preliminary line for
3401 failures, but not defers. However, always log it for defer, and log it for fail
3402 unless the sender_verify_fail log selector has been turned off. */
3404 if (sender_verified_failed &&
3405 !testflag(sender_verified_failed, af_sverify_told))
3407 BOOL save_rcpt_in_progress = fl.rcpt_in_progress;
3408 fl.rcpt_in_progress = FALSE; /* So as not to treat these as the error */
3410 setflag(sender_verified_failed, af_sverify_told);
3412 if (rc != FAIL || LOGGING(sender_verify_fail))
3413 log_write(0, LOG_MAIN|LOG_REJECT, "%s sender verify %s for <%s>%s",
3414 host_and_ident(TRUE),
3415 ((sender_verified_failed->special_action & 255) == DEFER)? "defer":"fail",
3416 sender_verified_failed->address,
3417 (sender_verified_failed->message == NULL)? US"" :
3418 string_sprintf(": %s", sender_verified_failed->message));
3420 if (rc == FAIL && sender_verified_failed->user_message)
3421 smtp_respond(smtp_code, codelen, FALSE, string_sprintf(
3422 testflag(sender_verified_failed, af_verify_pmfail)?
3423 "Postmaster verification failed while checking <%s>\n%s\n"
3424 "Several RFCs state that you are required to have a postmaster\n"
3425 "mailbox for each mail domain. This host does not accept mail\n"
3426 "from domains whose servers reject the postmaster address."
3428 testflag(sender_verified_failed, af_verify_nsfail)?
3429 "Callback setup failed while verifying <%s>\n%s\n"
3430 "The initial connection, or a HELO or MAIL FROM:<> command was\n"
3431 "rejected. Refusing MAIL FROM:<> does not help fight spam, disregards\n"
3432 "RFC requirements, and stops you from receiving standard bounce\n"
3433 "messages. This host does not accept mail from domains whose servers\n"
3436 "Verification failed for <%s>\n%s",
3437 sender_verified_failed->address,
3438 sender_verified_failed->user_message));
3440 fl.rcpt_in_progress = save_rcpt_in_progress;
3443 /* Sort out text for logging */
3445 log_msg = log_msg ? string_sprintf(": %s", log_msg) : US"";
3446 if ((lognl = Ustrchr(log_msg, '\n'))) *lognl = 0;
3448 /* Send permanent failure response to the command, but the code used isn't
3449 always a 5xx one - see comments at the start of this function. If the original
3450 rc was FAIL_DROP we drop the connection and yield 2. */
3453 smtp_respond(smtp_code, codelen, TRUE,
3454 user_msg ? user_msg : US"Administrative prohibition");
3456 /* Send temporary failure response to the command. Don't give any details,
3457 unless acl_temp_details is set. This is TRUE for a callout defer, a "defer"
3458 verb, and for a header verify when smtp_return_error_details is set.
3460 This conditional logic is all somewhat of a mess because of the odd
3461 interactions between temp_details and return_error_details. One day it should
3462 be re-implemented in a tidier fashion. */
3465 if (f.acl_temp_details && user_msg)
3467 if ( smtp_return_error_details
3468 && sender_verified_failed
3469 && sender_verified_failed->message
3471 smtp_respond(smtp_code, codelen, FALSE, sender_verified_failed->message);
3473 smtp_respond(smtp_code, codelen, TRUE, user_msg);
3476 smtp_respond(smtp_code, codelen, TRUE,
3477 US"Temporary local problem - please try later");
3479 /* Log the incident to the logs that are specified by log_reject_target
3480 (default main, reject). This can be empty to suppress logging of rejections. If
3481 the connection is not forcibly to be dropped, return 0. Otherwise, log why it
3482 is closing if required and return 2. */
3484 if (log_reject_target != 0)
3487 gstring * g = s_tlslog(NULL);
3488 uschar * tls = string_from_gstring(g);
3489 if (!tls) tls = US"";
3491 uschar * tls = US"";
3493 log_write(where == ACL_WHERE_CONNECT ? L_connection_reject : 0,
3494 log_reject_target, "%s%s%s %s%srejected %s%s",
3495 LOGGING(dnssec) && sender_host_dnssec ? US" DS" : US"",
3496 host_and_ident(TRUE),
3499 rc == FAIL ? US"" : US"temporarily ",
3503 if (!drop) return 0;
3505 log_write(L_smtp_connection, LOG_MAIN, "%s closed by DROP in ACL",
3506 smtp_get_connection_info());
3508 /* Run the not-quit ACL, but without any custom messages. This should not be a
3509 problem, because we get here only if some other ACL has issued "drop", and
3510 in that case, *its* custom messages will have been used above. */
3512 smtp_notquit_exit(US"acl-drop", NULL, NULL);
3519 /*************************************************
3520 * Handle SMTP exit when QUIT is not given *
3521 *************************************************/
3523 /* This function provides a logging/statistics hook for when an SMTP connection
3524 is dropped on the floor or the other end goes away. It's a global function
3525 because it's called from receive.c as well as this module. As well as running
3526 the NOTQUIT ACL, if there is one, this function also outputs a final SMTP
3527 response, either with a custom message from the ACL, or using a default. There
3528 is one case, however, when no message is output - after "drop". In that case,
3529 the ACL that obeyed "drop" has already supplied the custom message, and NULL is
3530 passed to this function.
3532 In case things go wrong while processing this function, causing an error that
3533 may re-enter this function, there is a recursion check.
3536 reason What $smtp_notquit_reason will be set to in the ACL;
3537 if NULL, the ACL is not run
3538 code The error code to return as part of the response
3539 defaultrespond The default message if there's no user_msg
3545 smtp_notquit_exit(uschar *reason, uschar *code, uschar *defaultrespond, ...)
3548 uschar *user_msg = NULL;
3549 uschar *log_msg = NULL;
3551 /* Check for recursive call */
3553 if (fl.smtp_exit_function_called)
3555 log_write(0, LOG_PANIC, "smtp_notquit_exit() called more than once (%s)",
3559 fl.smtp_exit_function_called = TRUE;
3561 /* Call the not-QUIT ACL, if there is one, unless no reason is given. */
3563 if (acl_smtp_notquit && reason)
3565 smtp_notquit_reason = reason;
3566 if ((rc = acl_check(ACL_WHERE_NOTQUIT, NULL, acl_smtp_notquit, &user_msg,
3567 &log_msg)) == ERROR)
3568 log_write(0, LOG_MAIN|LOG_PANIC, "ACL for not-QUIT returned ERROR: %s",
3572 /* If the connection was dropped, we certainly are no longer talking TLS */
3573 tls_in.active.sock = -1;
3575 /* Write an SMTP response if we are expected to give one. As the default
3576 responses are all internal, they should be reasonable size. */
3578 if (code && defaultrespond)
3581 smtp_respond(code, 3, TRUE, user_msg);
3587 va_start(ap, defaultrespond);
3588 g = string_vformat(NULL, SVFMT_EXTEND|SVFMT_REBUFFER, CS defaultrespond, ap);
3590 smtp_printf("%s %s\r\n", FALSE, code, string_from_gstring(g));
3599 /*************************************************
3600 * Verify HELO argument *
3601 *************************************************/
3603 /* This function is called if helo_verify_hosts or helo_try_verify_hosts is
3604 matched. It is also called from ACL processing if verify = helo is used and
3605 verification was not previously tried (i.e. helo_try_verify_hosts was not
3606 matched). The result of its processing is to set helo_verified and
3607 helo_verify_failed. These variables should both be FALSE for this function to
3610 Note that EHLO/HELO is legitimately allowed to quote an address literal. Allow
3611 for IPv6 ::ffff: literals.
3614 Returns: TRUE if testing was completed;
3615 FALSE on a temporary failure
3619 smtp_verify_helo(void)
3623 HDEBUG(D_receive) debug_printf("verifying EHLO/HELO argument \"%s\"\n",
3626 if (sender_helo_name == NULL)
3628 HDEBUG(D_receive) debug_printf("no EHLO/HELO command was issued\n");
3631 /* Deal with the case of -bs without an IP address */
3633 else if (sender_host_address == NULL)
3635 HDEBUG(D_receive) debug_printf("no client IP address: assume success\n");
3636 f.helo_verified = TRUE;
3639 /* Deal with the more common case when there is a sending IP address */
3641 else if (sender_helo_name[0] == '[')
3643 f.helo_verified = Ustrncmp(sender_helo_name+1, sender_host_address,
3644 Ustrlen(sender_host_address)) == 0;
3647 if (!f.helo_verified)
3649 if (strncmpic(sender_host_address, US"::ffff:", 7) == 0)
3650 f.helo_verified = Ustrncmp(sender_helo_name + 1,
3651 sender_host_address + 7, Ustrlen(sender_host_address) - 7) == 0;
3656 { if (f.helo_verified) debug_printf("matched host address\n"); }
3659 /* Do a reverse lookup if one hasn't already given a positive or negative
3660 response. If that fails, or the name doesn't match, try checking with a forward
3665 if (sender_host_name == NULL && !host_lookup_failed)
3666 yield = host_name_lookup() != DEFER;
3668 /* If a host name is known, check it and all its aliases. */
3670 if (sender_host_name)
3671 if ((f.helo_verified = strcmpic(sender_host_name, sender_helo_name) == 0))
3673 sender_helo_dnssec = sender_host_dnssec;
3674 HDEBUG(D_receive) debug_printf("matched host name\n");
3678 uschar **aliases = sender_host_aliases;
3680 if ((f.helo_verified = strcmpic(*aliases++, sender_helo_name) == 0))
3682 sender_helo_dnssec = sender_host_dnssec;
3686 HDEBUG(D_receive) if (f.helo_verified)
3687 debug_printf("matched alias %s\n", *(--aliases));
3690 /* Final attempt: try a forward lookup of the helo name */
3692 if (!f.helo_verified)
3696 {.name = sender_helo_name, .address = NULL, .mx = MX_NONE, .next = NULL};
3698 {.request = US"*", .require = US""};
3700 HDEBUG(D_receive) debug_printf("getting IP address for %s\n",
3702 rc = host_find_bydns(&h, NULL, HOST_FIND_BY_A | HOST_FIND_BY_AAAA,
3703 NULL, NULL, NULL, &d, NULL, NULL);
3704 if (rc == HOST_FOUND || rc == HOST_FOUND_LOCAL)
3705 for (host_item * hh = &h; hh; hh = hh->next)
3706 if (Ustrcmp(hh->address, sender_host_address) == 0)
3708 f.helo_verified = TRUE;
3709 if (h.dnssec == DS_YES) sender_helo_dnssec = TRUE;
3711 debug_printf("IP address for %s matches calling address\n"
3712 "Forward DNS security status: %sverified\n",
3713 sender_helo_name, sender_helo_dnssec ? "" : "un");
3719 if (!f.helo_verified) f.helo_verify_failed = TRUE; /* We've tried ... */
3726 /*************************************************
3727 * Send user response message *
3728 *************************************************/
3730 /* This function is passed a default response code and a user message. It calls
3731 smtp_message_code() to check and possibly modify the response code, and then
3732 calls smtp_respond() to transmit the response. I put this into a function
3733 just to avoid a lot of repetition.
3736 code the response code
3737 user_msg the user message
3743 smtp_user_msg(uschar *code, uschar *user_msg)
3746 smtp_message_code(&code, &len, &user_msg, NULL, TRUE);
3747 smtp_respond(code, len, TRUE, user_msg);
3753 smtp_in_auth(auth_instance *au, uschar ** s, uschar ** ss)
3755 const uschar *set_id = NULL;
3758 /* Run the checking code, passing the remainder of the command line as
3759 data. Initials the $auth<n> variables as empty. Initialize $0 empty and set
3760 it as the only set numerical variable. The authenticator may set $auth<n>
3761 and also set other numeric variables. The $auth<n> variables are preferred
3762 nowadays; the numerical variables remain for backwards compatibility.
3764 Afterwards, have a go at expanding the set_id string, even if
3765 authentication failed - for bad passwords it can be useful to log the
3766 userid. On success, require set_id to expand and exist, and put it in
3767 authenticated_id. Save this in permanent store, as the working store gets
3768 reset at HELO, RSET, etc. */
3770 for (int i = 0; i < AUTH_VARS; i++) auth_vars[i] = NULL;
3772 expand_nlength[0] = 0; /* $0 contains nothing */
3774 rc = (au->info->servercode)(au, smtp_cmd_data);
3775 if (au->set_id) set_id = expand_string(au->set_id);
3776 expand_nmax = -1; /* Reset numeric variables */
3777 for (int i = 0; i < AUTH_VARS; i++) auth_vars[i] = NULL; /* Reset $auth<n> */
3779 /* The value of authenticated_id is stored in the spool file and printed in
3780 log lines. It must not contain binary zeros or newline characters. In
3781 normal use, it never will, but when playing around or testing, this error
3782 can (did) happen. To guard against this, ensure that the id contains only
3783 printing characters. */
3785 if (set_id) set_id = string_printing(set_id);
3787 /* For the non-OK cases, set up additional logging data if set_id
3791 set_id = set_id && *set_id
3792 ? string_sprintf(" (set_id=%s)", set_id) : US"";
3794 /* Switch on the result */
3799 if (!au->set_id || set_id) /* Complete success */
3801 if (set_id) authenticated_id = string_copy_perm(set_id, TRUE);
3802 sender_host_authenticated = au->name;
3803 sender_host_auth_pubname = au->public_name;
3804 authentication_failed = FALSE;
3805 authenticated_fail_id = NULL; /* Impossible to already be set? */
3808 (sender_host_address ? protocols : protocols_local)
3809 [pextend + pauthed + (tls_in.active.sock >= 0 ? pcrpted:0)];
3810 *s = *ss = US"235 Authentication succeeded";
3811 authenticated_by = au;
3815 /* Authentication succeeded, but we failed to expand the set_id string.
3816 Treat this as a temporary error. */
3818 auth_defer_msg = expand_string_message;
3822 if (set_id) authenticated_fail_id = string_copy_perm(set_id, TRUE);
3823 *s = string_sprintf("435 Unable to authenticate at present%s",
3824 auth_defer_user_msg);
3825 *ss = string_sprintf("435 Unable to authenticate at present%s: %s",
3826 set_id, auth_defer_msg);
3830 *s = *ss = US"501 Invalid base64 data";
3834 *s = *ss = US"501 Authentication cancelled";
3838 *s = *ss = US"553 Initial data not expected";
3842 if (set_id) authenticated_fail_id = string_copy_perm(set_id, TRUE);
3843 *s = US"535 Incorrect authentication data";
3844 *ss = string_sprintf("535 Incorrect authentication data%s", set_id);
3848 if (set_id) authenticated_fail_id = string_copy_perm(set_id, TRUE);
3849 *s = US"435 Internal error";
3850 *ss = string_sprintf("435 Internal error%s: return %d from authentication "
3851 "check", set_id, rc);
3863 qualify_recipient(uschar ** recipient, uschar * smtp_cmd_data, uschar * tag)
3866 if (f.allow_unqualified_recipient || strcmpic(*recipient, US"postmaster") == 0)
3868 DEBUG(D_receive) debug_printf("unqualified address %s accepted\n",
3870 rd = Ustrlen(recipient) + 1;
3871 /* deconst ok as *recipient was not const */
3872 *recipient = US rewrite_address_qualify(*recipient, TRUE);
3875 smtp_printf("501 %s: recipient address must contain a domain\r\n", FALSE,
3877 log_write(L_smtp_syntax_error,
3878 LOG_MAIN|LOG_REJECT, "unqualified %s rejected: <%s> %s%s",
3879 tag, *recipient, host_and_ident(TRUE), host_lookup_msg);
3887 smtp_quit_handler(uschar ** user_msgp, uschar ** log_msgp)
3890 f.smtp_in_quit = TRUE;
3891 incomplete_transaction_log(US"QUIT");
3893 && acl_check(ACL_WHERE_QUIT, NULL, acl_smtp_quit, user_msgp, log_msgp)
3895 log_write(0, LOG_MAIN|LOG_PANIC, "ACL for QUIT returned ERROR: %s",
3898 #ifdef EXIM_TCP_CORK
3899 (void) setsockopt(fileno(smtp_out), IPPROTO_TCP, EXIM_TCP_CORK, US &on, sizeof(on));
3903 smtp_respond(US"221", 3, TRUE, *user_msgp);
3905 smtp_printf("221 %s closing connection\r\n", FALSE, smtp_active_hostname);
3907 #ifdef SERVERSIDE_CLOSE_NOWAIT
3908 # ifndef DISABLE_TLS
3909 tls_close(NULL, TLS_SHUTDOWN_NOWAIT);
3912 log_write(L_smtp_connection, LOG_MAIN, "%s closed by QUIT",
3913 smtp_get_connection_info());
3916 # ifndef DISABLE_TLS
3917 tls_close(NULL, TLS_SHUTDOWN_WAIT);
3920 log_write(L_smtp_connection, LOG_MAIN, "%s closed by QUIT",
3921 smtp_get_connection_info());
3923 /* Pause, hoping client will FIN first so that they get the TIME_WAIT.
3924 The socket should become readble (though with no data) */
3927 int fd = fileno(smtp_in);
3929 struct timeval t_limit = {.tv_sec = 0, .tv_usec = 200*1000};
3933 (void) select(fd + 1, (SELECT_ARG2_TYPE *)&fds, NULL, NULL, &t_limit);
3935 #endif /*!DAEMON_CLOSE_NOWAIT*/
3940 smtp_rset_handler(void)
3943 incomplete_transaction_log(US"RSET");
3944 smtp_printf("250 Reset OK\r\n", FALSE);
3945 cmd_list[CMD_LIST_RSET].is_mail_cmd = FALSE;
3950 expand_mailmax(const uschar * s)
3952 if (!(s = expand_cstring(s)))
3953 log_write(0, LOG_MAIN|LOG_PANIC, "failed to expand smtp_accept_max_per_connection");
3954 return *s ? Uatoi(s) : 0;
3957 /*************************************************
3958 * Initialize for SMTP incoming message *
3959 *************************************************/
3961 /* This function conducts the initial dialogue at the start of an incoming SMTP
3962 message, and builds a list of recipients. However, if the incoming message
3963 is part of a batch (-bS option) a separate function is called since it would
3964 be messy having tests splattered about all over this function. This function
3965 therefore handles the case where interaction is occurring. The input and output
3966 files are set up in smtp_in and smtp_out.
3968 The global recipients_list is set to point to a vector of recipient_item
3969 blocks, whose number is given by recipients_count. This is extended by the
3970 receive_add_recipient() function. The global variable sender_address is set to
3971 the sender's address. The yield is +1 if a message has been successfully
3972 started, 0 if a QUIT command was encountered or the connection was refused from
3973 the particular host, or -1 if the connection was lost.
3977 Returns: > 0 message successfully started (reached DATA)
3978 = 0 QUIT read or end of file reached or call refused
3983 smtp_setup_msg(void)
3986 BOOL toomany = FALSE;
3987 BOOL discarded = FALSE;
3988 BOOL last_was_rej_mail = FALSE;
3989 BOOL last_was_rcpt = FALSE;
3990 rmark reset_point = store_mark();
3992 DEBUG(D_receive) debug_printf("smtp_setup_msg entered\n");
3994 /* Reset for start of new message. We allow one RSET not to be counted as a
3995 nonmail command, for those MTAs that insist on sending it between every
3996 message. Ditto for EHLO/HELO and for STARTTLS, to allow for going in and out of
3997 TLS between messages (an Exim client may do this if it has messages queued up
3998 for the host). Note: we do NOT reset AUTH at this point. */
4000 reset_point = smtp_reset(reset_point);
4001 message_ended = END_NOTSTARTED;
4003 chunking_state = f.chunking_offered ? CHUNKING_OFFERED : CHUNKING_NOT_OFFERED;
4005 cmd_list[CMD_LIST_RSET].is_mail_cmd = TRUE;
4006 cmd_list[CMD_LIST_HELO].is_mail_cmd = TRUE;
4007 cmd_list[CMD_LIST_EHLO].is_mail_cmd = TRUE;
4009 cmd_list[CMD_LIST_STARTTLS].is_mail_cmd = TRUE;
4012 if (lwr_receive_getc != NULL)
4014 /* This should have already happened, but if we've gotten confused,
4015 force a reset here. */
4016 DEBUG(D_receive) debug_printf("WARNING: smtp_setup_msg had to restore receive functions to lowers\n");
4017 bdat_pop_receive_functions();
4020 /* Set the local signal handler for SIGTERM - it tries to end off tidily */
4022 had_command_sigterm = 0;
4023 os_non_restarting_signal(SIGTERM, command_sigterm_handler);
4025 /* Batched SMTP is handled in a different function. */
4027 if (smtp_batched_input) return smtp_setup_batch_msg();
4030 if (smtp_in) /* Avoid pure-ACKs while in cmd pingpong phase */
4031 (void) setsockopt(fileno(smtp_in), IPPROTO_TCP, TCP_QUICKACK,
4032 US &off, sizeof(off));
4035 /* Deal with SMTP commands. This loop is exited by setting done to a POSITIVE
4036 value. The values are 2 larger than the required yield of the function. */
4040 const uschar **argv;
4041 uschar *etrn_command;
4042 uschar *etrn_serialize_key;
4044 uschar *log_msg, *smtp_code;
4045 uschar *user_msg = NULL;
4046 uschar *recipient = NULL;
4047 uschar *hello = NULL;
4049 BOOL was_rej_mail = FALSE;
4050 BOOL was_rcpt = FALSE;
4051 void (*oldsignal)(int);
4053 int start, end, sender_domain, recipient_domain;
4056 uschar *orcpt = NULL;
4061 /* Check once per STARTTLS or SSL-on-connect for a TLS AUTH */
4062 if ( tls_in.active.sock >= 0
4064 && tls_in.certificate_verified
4065 && cmd_list[CMD_LIST_TLS_AUTH].is_mail_cmd
4068 cmd_list[CMD_LIST_TLS_AUTH].is_mail_cmd = FALSE;
4070 for (auth_instance * au = auths; au; au = au->next)
4071 if (strcmpic(US"tls", au->driver_name) == 0)
4074 && (rc = acl_check(ACL_WHERE_AUTH, NULL, acl_smtp_auth,
4075 &user_msg, &log_msg)) != OK
4077 done = smtp_handle_acl_fail(ACL_WHERE_AUTH, rc, user_msg, log_msg);
4080 smtp_cmd_data = NULL;
4082 if (smtp_in_auth(au, &s, &ss) == OK)
4083 { DEBUG(D_auth) debug_printf("tls auth succeeded\n"); }
4085 { DEBUG(D_auth) debug_printf("tls auth not succeeded\n"); }
4092 switch(smtp_read_command(
4093 #ifndef DISABLE_PIPE_CONNECT
4094 !fl.pipe_connect_acceptable,
4098 GETC_BUFFER_UNLIMITED))
4100 /* The AUTH command is not permitted to occur inside a transaction, and may
4101 occur successfully only once per connection. Actually, that isn't quite
4102 true. When TLS is started, all previous information about a connection must
4103 be discarded, so a new AUTH is permitted at that time.
4105 AUTH may only be used when it has been advertised. However, it seems that
4106 there are clients that send AUTH when it hasn't been advertised, some of
4107 them even doing this after HELO. And there are MTAs that accept this. Sigh.
4108 So there's a get-out that allows this to happen.
4110 AUTH is initially labelled as a "nonmail command" so that one occurrence
4111 doesn't get counted. We change the label here so that multiple failing
4112 AUTHS will eventually hit the nonmail threshold. */
4116 authentication_failed = TRUE;
4117 cmd_list[CMD_LIST_AUTH].is_mail_cmd = FALSE;
4119 if (!fl.auth_advertised && !f.allow_auth_unadvertised)
4121 done = synprot_error(L_smtp_protocol_error, 503, NULL,
4122 US"AUTH command used when not advertised");
4125 if (sender_host_authenticated)
4127 done = synprot_error(L_smtp_protocol_error, 503, NULL,
4128 US"already authenticated");
4133 done = synprot_error(L_smtp_protocol_error, 503, NULL,
4134 US"not permitted in mail transaction");
4141 && (rc = acl_check(ACL_WHERE_AUTH, NULL, acl_smtp_auth,
4142 &user_msg, &log_msg)) != OK
4145 done = smtp_handle_acl_fail(ACL_WHERE_AUTH, rc, user_msg, log_msg);
4149 /* Find the name of the requested authentication mechanism. */
4152 for (; (c = *smtp_cmd_data) && !isspace(c); smtp_cmd_data++)
4153 if (!isalnum(c) && c != '-' && c != '_')
4155 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4156 US"invalid character in authentication mechanism name");
4160 /* If not at the end of the line, we must be at white space. Terminate the
4161 name and move the pointer on to any data that may be present. */
4165 *smtp_cmd_data++ = 0;
4166 while (isspace(*smtp_cmd_data)) smtp_cmd_data++;
4169 /* Search for an authentication mechanism which is configured for use
4170 as a server and which has been advertised (unless, sigh, allow_auth_
4171 unadvertised is set). */
4175 for (au = auths; au; au = au->next)
4176 if (strcmpic(s, au->public_name) == 0 && au->server &&
4177 (au->advertised || f.allow_auth_unadvertised))
4182 c = smtp_in_auth(au, &s, &ss);
4184 smtp_printf("%s\r\n", FALSE, s);
4186 log_write(0, LOG_MAIN|LOG_REJECT, "%s authenticator failed for %s: %s",
4187 au->name, host_and_ident(FALSE), ss);
4190 done = synprot_error(L_smtp_protocol_error, 504, NULL,
4191 string_sprintf("%s authentication mechanism not supported", s));
4194 break; /* AUTH_CMD */
4196 /* The HELO/EHLO commands are permitted to appear in the middle of a
4197 session as well as at the beginning. They have the effect of a reset in
4198 addition to their other functions. Their absence at the start cannot be
4199 taken to be an error.
4203 If the EHLO command is not acceptable to the SMTP server, 501, 500,
4204 or 502 failure replies MUST be returned as appropriate. The SMTP
4205 server MUST stay in the same state after transmitting these replies
4206 that it was in before the EHLO was received.
4208 Therefore, we do not do the reset until after checking the command for
4209 acceptability. This change was made for Exim release 4.11. Previously
4210 it did the reset first. */
4223 HELO_EHLO: /* Common code for HELO and EHLO */
4224 cmd_list[CMD_LIST_HELO].is_mail_cmd = FALSE;
4225 cmd_list[CMD_LIST_EHLO].is_mail_cmd = FALSE;
4227 /* Reject the HELO if its argument was invalid or non-existent. A
4228 successful check causes the argument to be saved in malloc store. */
4230 if (!check_helo(smtp_cmd_data))
4232 smtp_printf("501 Syntactically invalid %s argument(s)\r\n", FALSE, hello);
4234 log_write(0, LOG_MAIN|LOG_REJECT, "rejected %s from %s: syntactically "
4235 "invalid argument(s): %s", hello, host_and_ident(FALSE),
4236 *smtp_cmd_argument == 0 ? US"(no argument given)" :
4237 string_printing(smtp_cmd_argument));
4239 if (++synprot_error_count > smtp_max_synprot_errors)
4241 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
4242 "syntax or protocol errors (last command was \"%s\", %s)",
4243 host_and_ident(FALSE), string_printing(smtp_cmd_buffer),
4244 string_from_gstring(s_connhad_log(NULL))
4252 /* If sender_host_unknown is true, we have got here via the -bs interface,
4253 not called from inetd. Otherwise, we are running an IP connection and the
4254 host address will be set. If the helo name is the primary name of this
4255 host and we haven't done a reverse lookup, force one now. If helo_verify_required
4256 is set, ensure that the HELO name matches the actual host. If helo_verify
4257 is set, do the same check, but softly. */
4259 if (!f.sender_host_unknown)
4261 BOOL old_helo_verified = f.helo_verified;
4262 uschar *p = smtp_cmd_data;
4264 while (*p != 0 && !isspace(*p)) { *p = tolower(*p); p++; }
4267 /* Force a reverse lookup if HELO quoted something in helo_lookup_domains
4268 because otherwise the log can be confusing. */
4270 if ( !sender_host_name
4271 && match_isinlist(sender_helo_name, CUSS &helo_lookup_domains, 0,
4272 &domainlist_anchor, NULL, MCL_DOMAIN, TRUE, NULL) == OK)
4273 (void)host_name_lookup();
4275 /* Rebuild the fullhost info to include the HELO name (and the real name
4276 if it was looked up.) */
4278 host_build_sender_fullhost(); /* Rebuild */
4279 set_process_info("handling%s incoming connection from %s",
4280 tls_in.active.sock >= 0 ? " TLS" : "", host_and_ident(FALSE));
4282 /* Verify if configured. This doesn't give much security, but it does
4283 make some people happy to be able to do it. If helo_verify_required is set,
4284 (host matches helo_verify_hosts) failure forces rejection. If helo_verify
4285 is set (host matches helo_try_verify_hosts), it does not. This is perhaps
4286 now obsolescent, since the verification can now be requested selectively
4289 f.helo_verified = f.helo_verify_failed = sender_helo_dnssec = FALSE;
4290 if (fl.helo_verify_required || fl.helo_verify)
4292 BOOL tempfail = !smtp_verify_helo();
4293 if (!f.helo_verified)
4295 if (fl.helo_verify_required)
4297 smtp_printf("%d %s argument does not match calling host\r\n", FALSE,
4298 tempfail? 451 : 550, hello);
4299 log_write(0, LOG_MAIN|LOG_REJECT, "%srejected \"%s %s\" from %s",
4300 tempfail? "temporarily " : "",
4301 hello, sender_helo_name, host_and_ident(FALSE));
4302 f.helo_verified = old_helo_verified;
4303 break; /* End of HELO/EHLO processing */
4305 HDEBUG(D_all) debug_printf("%s verification failed but host is in "
4306 "helo_try_verify_hosts\n", hello);
4312 /* set up SPF context */
4313 spf_conn_init(sender_helo_name, sender_host_address);
4316 /* Apply an ACL check if one is defined; afterwards, recheck
4317 synchronization in case the client started sending in a delay. */
4320 if ((rc = acl_check(ACL_WHERE_HELO, NULL, acl_smtp_helo,
4321 &user_msg, &log_msg)) != OK)
4323 done = smtp_handle_acl_fail(ACL_WHERE_HELO, rc, user_msg, log_msg);
4324 sender_helo_name = NULL;
4325 host_build_sender_fullhost(); /* Rebuild */
4328 #ifndef DISABLE_PIPE_CONNECT
4329 else if (!fl.pipe_connect_acceptable && !check_sync())
4331 else if (!check_sync())
4335 /* Generate an OK reply. The default string includes the ident if present,
4336 and also the IP address if present. Reflecting back the ident is intended
4337 as a deterrent to mail forgers. For maximum efficiency, and also because
4338 some broken systems expect each response to be in a single packet, arrange
4339 that the entire reply is sent in one write(). */
4341 fl.auth_advertised = FALSE;
4342 f.smtp_in_pipelining_advertised = FALSE;
4344 fl.tls_advertised = FALSE;
4346 fl.dsn_advertised = FALSE;
4348 fl.smtputf8_advertised = FALSE;
4351 /* Expand the per-connection message count limit option */
4352 smtp_mailcmd_max = expand_mailmax(smtp_accept_max_per_connection);
4354 smtp_code = US"250 "; /* Default response code plus space*/
4357 /* sender_host_name below will be tainted, so save on copy when we hit it */
4358 g = string_get_tainted(24, TRUE);
4359 g = string_fmt_append(g, "%.3s %s Hello %s%s%s",
4361 smtp_active_hostname,
4362 sender_ident ? sender_ident : US"",
4363 sender_ident ? US" at " : US"",
4364 sender_host_name ? sender_host_name : sender_helo_name);
4366 if (sender_host_address)
4367 g = string_fmt_append(g, " [%s]", sender_host_address);
4370 /* A user-supplied EHLO greeting may not contain more than one line. Note
4371 that the code returned by smtp_message_code() includes the terminating
4372 whitespace character. */
4378 smtp_message_code(&smtp_code, &codelen, &user_msg, NULL, TRUE);
4379 s = string_sprintf("%.*s%s", codelen, smtp_code, user_msg);
4380 if ((ss = strpbrk(CS s, "\r\n")) != NULL)
4382 log_write(0, LOG_MAIN|LOG_PANIC, "EHLO/HELO response must not contain "
4383 "newlines: message truncated: %s", string_printing(s));
4386 g = string_cat(NULL, s);
4389 g = string_catn(g, US"\r\n", 2);
4391 /* If we received EHLO, we must create a multiline response which includes
4392 the functions supported. */
4398 /* I'm not entirely happy with this, as an MTA is supposed to check
4399 that it has enough room to accept a message of maximum size before
4400 it sends this. However, there seems little point in not sending it.
4401 The actual size check happens later at MAIL FROM time. By postponing it
4402 till then, VRFY and EXPN can be used after EHLO when space is short. */
4404 if (thismessage_size_limit > 0)
4405 g = string_fmt_append(g, "%.3s-SIZE %d\r\n", smtp_code,
4406 thismessage_size_limit);
4409 g = string_catn(g, smtp_code, 3);
4410 g = string_catn(g, US"-SIZE\r\n", 7);
4413 #ifdef EXPERIMENTAL_ESMTP_LIMITS
4414 if ( (smtp_mailcmd_max > 0 || recipients_max)
4415 && verify_check_host(&limits_advertise_hosts) == OK)
4417 g = string_fmt_append(g, "%.3s-LIMITS", smtp_code);
4418 if (smtp_mailcmd_max > 0)
4419 g = string_fmt_append(g, " MAILMAX=%d", smtp_mailcmd_max);
4421 g = string_fmt_append(g, " RCPTMAX=%d", recipients_max);
4422 g = string_catn(g, US"\r\n", 2);
4426 /* Exim does not do protocol conversion or data conversion. It is 8-bit
4427 clean; if it has an 8-bit character in its hand, it just sends it. It
4428 cannot therefore specify 8BITMIME and remain consistent with the RFCs.
4429 However, some users want this option simply in order to stop MUAs
4430 mangling messages that contain top-bit-set characters. It is therefore
4431 provided as an option. */
4433 if (accept_8bitmime)
4435 g = string_catn(g, smtp_code, 3);
4436 g = string_catn(g, US"-8BITMIME\r\n", 11);
4439 /* Advertise DSN support if configured to do so. */
4440 if (verify_check_host(&dsn_advertise_hosts) != FAIL)
4442 g = string_catn(g, smtp_code, 3);
4443 g = string_catn(g, US"-DSN\r\n", 6);
4444 fl.dsn_advertised = TRUE;
4447 /* Advertise ETRN/VRFY/EXPN if there's are ACL checking whether a host is
4448 permitted to issue them; a check is made when any host actually tries. */
4452 g = string_catn(g, smtp_code, 3);
4453 g = string_catn(g, US"-ETRN\r\n", 7);
4457 g = string_catn(g, smtp_code, 3);
4458 g = string_catn(g, US"-VRFY\r\n", 7);
4462 g = string_catn(g, smtp_code, 3);
4463 g = string_catn(g, US"-EXPN\r\n", 7);
4466 /* Exim is quite happy with pipelining, so let the other end know that
4467 it is safe to use it, unless advertising is disabled. */
4469 if ( f.pipelining_enable
4470 && verify_check_host(&pipelining_advertise_hosts) == OK)
4472 g = string_catn(g, smtp_code, 3);
4473 g = string_catn(g, US"-PIPELINING\r\n", 13);
4474 sync_cmd_limit = NON_SYNC_CMD_PIPELINING;
4475 f.smtp_in_pipelining_advertised = TRUE;
4477 #ifndef DISABLE_PIPE_CONNECT
4478 if (fl.pipe_connect_acceptable)
4480 f.smtp_in_early_pipe_advertised = TRUE;
4481 g = string_catn(g, smtp_code, 3);
4482 g = string_catn(g, US"-" EARLY_PIPE_FEATURE_NAME "\r\n", EARLY_PIPE_FEATURE_LEN+3);
4488 /* If any server authentication mechanisms are configured, advertise
4489 them if the current host is in auth_advertise_hosts. The problem with
4490 advertising always is that some clients then require users to
4491 authenticate (and aren't configurable otherwise) even though it may not
4492 be necessary (e.g. if the host is in host_accept_relay).
4494 RFC 2222 states that SASL mechanism names contain only upper case
4495 letters, so output the names in upper case, though we actually recognize
4496 them in either case in the AUTH command. */
4500 && !sender_host_authenticated
4502 && verify_check_host(&auth_advertise_hosts) == OK
4506 for (auth_instance * au = auths; au; au = au->next)
4508 au->advertised = FALSE;
4511 DEBUG(D_auth+D_expand) debug_printf_indent(
4512 "Evaluating advertise_condition for %s %s athenticator\n",
4513 au->name, au->public_name);
4514 if ( !au->advertise_condition
4515 || expand_check_condition(au->advertise_condition, au->name,
4522 g = string_catn(g, smtp_code, 3);
4523 g = string_catn(g, US"-AUTH", 5);
4525 fl.auth_advertised = TRUE;
4528 g = string_catn(g, US" ", 1);
4529 g = string_cat (g, au->public_name);
4530 while (++saveptr < g->ptr) g->s[saveptr] = toupper(g->s[saveptr]);
4531 au->advertised = TRUE;
4536 if (!first) g = string_catn(g, US"\r\n", 2);
4539 /* RFC 3030 CHUNKING */
4541 if (verify_check_host(&chunking_advertise_hosts) != FAIL)
4543 g = string_catn(g, smtp_code, 3);
4544 g = string_catn(g, US"-CHUNKING\r\n", 11);
4545 f.chunking_offered = TRUE;
4546 chunking_state = CHUNKING_OFFERED;
4549 /* Advertise TLS (Transport Level Security) aka SSL (Secure Socket Layer)
4550 if it has been included in the binary, and the host matches
4551 tls_advertise_hosts. We must *not* advertise if we are already in a
4552 secure connection. */
4555 if (tls_in.active.sock < 0 &&
4556 verify_check_host(&tls_advertise_hosts) != FAIL)
4558 g = string_catn(g, smtp_code, 3);
4559 g = string_catn(g, US"-STARTTLS\r\n", 11);
4560 fl.tls_advertised = TRUE;
4564 #ifndef DISABLE_PRDR
4565 /* Per Recipient Data Response, draft by Eric A. Hall extending RFC */
4568 g = string_catn(g, smtp_code, 3);
4569 g = string_catn(g, US"-PRDR\r\n", 7);
4574 if ( accept_8bitmime
4575 && verify_check_host(&smtputf8_advertise_hosts) != FAIL)
4577 g = string_catn(g, smtp_code, 3);
4578 g = string_catn(g, US"-SMTPUTF8\r\n", 11);
4579 fl.smtputf8_advertised = TRUE;
4583 /* Finish off the multiline reply with one that is always available. */
4585 g = string_catn(g, smtp_code, 3);
4586 g = string_catn(g, US" HELP\r\n", 7);
4589 /* Terminate the string (for debug), write it, and note that HELO/EHLO
4593 if (tls_in.active.sock >= 0)
4594 (void)tls_write(NULL, g->s, g->ptr,
4595 # ifndef DISABLE_PIPE_CONNECT
4596 fl.pipe_connect_acceptable && pipeline_connect_sends());
4602 (void) fwrite(g->s, 1, g->ptr, smtp_out);
4608 (void) string_from_gstring(g);
4609 while ((cr = Ustrchr(g->s, '\r')) != NULL) /* lose CRs */
4610 memmove(cr, cr + 1, (g->ptr--) - (cr - g->s));
4611 debug_printf("SMTP>> %s", g->s);
4613 fl.helo_seen = TRUE;
4615 /* Reset the protocol and the state, abandoning any previous message. */
4617 (sender_host_address ? protocols : protocols_local)
4619 ? pextend + (sender_host_authenticated ? pauthed : 0)
4621 + (tls_in.active.sock >= 0 ? pcrpted : 0)
4623 cancel_cutthrough_connection(TRUE, US"sent EHLO response");
4624 reset_point = smtp_reset(reset_point);
4626 break; /* HELO/EHLO */
4629 /* The MAIL command requires an address as an operand. All we do
4630 here is to parse it for syntactic correctness. The form "<>" is
4631 a special case which converts into an empty string. The start/end
4632 pointers in the original are not used further for this address, as
4633 it is the canonical extracted address which is all that is kept. */
4637 smtp_mailcmd_count++; /* Count for limit and ratelimit */
4639 was_rej_mail = TRUE; /* Reset if accepted */
4640 env_mail_type_t * mail_args; /* Sanity check & validate args */
4643 if ( fl.helo_verify_required
4644 || verify_check_host(&hosts_require_helo) == OK)
4646 smtp_printf("503 HELO or EHLO required\r\n", FALSE);
4647 log_write(0, LOG_MAIN|LOG_REJECT, "rejected MAIL from %s: no "
4648 "HELO/EHLO given", host_and_ident(FALSE));
4651 else if (smtp_mailcmd_max < 0)
4652 smtp_mailcmd_max = expand_mailmax(smtp_accept_max_per_connection);
4656 done = synprot_error(L_smtp_protocol_error, 503, NULL,
4657 US"sender already given");
4661 if (!*smtp_cmd_data)
4663 done = synprot_error(L_smtp_protocol_error, 501, NULL,
4664 US"MAIL must have an address operand");
4668 /* Check to see if the limit for messages per connection would be
4669 exceeded by accepting further messages. */
4671 if (smtp_mailcmd_max > 0 && smtp_mailcmd_count > smtp_mailcmd_max)
4673 smtp_printf("421 too many messages in this connection\r\n", FALSE);
4674 log_write(0, LOG_MAIN|LOG_REJECT, "rejected MAIL command %s: too many "
4675 "messages in one connection", host_and_ident(TRUE));
4679 /* Reset for start of message - even if this is going to fail, we
4680 obviously need to throw away any previous data. */
4682 cancel_cutthrough_connection(TRUE, US"MAIL received");
4683 reset_point = smtp_reset(reset_point);
4685 sender_data = recipient_data = NULL;
4687 /* Loop, checking for ESMTP additions to the MAIL FROM command. */
4689 if (fl.esmtp) for(;;)
4691 uschar *name, *value, *end;
4692 unsigned long int size;
4693 BOOL arg_error = FALSE;
4695 if (!extract_option(&name, &value)) break;
4697 for (mail_args = env_mail_type_list;
4698 mail_args->value != ENV_MAIL_OPT_NULL;
4701 if (strcmpic(name, mail_args->name) == 0)
4703 if (mail_args->need_value && strcmpic(value, US"") == 0)
4706 switch(mail_args->value)
4708 /* Handle SIZE= by reading the value. We don't do the check till later,
4709 in order to be able to log the sender address on failure. */
4710 case ENV_MAIL_OPT_SIZE:
4711 if (((size = Ustrtoul(value, &end, 10)), *end == 0))
4713 if ((size == ULONG_MAX && errno == ERANGE) || size > INT_MAX)
4715 message_size = (int)size;
4721 /* If this session was initiated with EHLO and accept_8bitmime is set,
4722 Exim will have indicated that it supports the BODY=8BITMIME option. In
4723 fact, it does not support this according to the RFCs, in that it does not
4724 take any special action for forwarding messages containing 8-bit
4725 characters. That is why accept_8bitmime is not the default setting, but
4726 some sites want the action that is provided. We recognize both "8BITMIME"
4727 and "7BIT" as body types, but take no action. */
4728 case ENV_MAIL_OPT_BODY:
4729 if (accept_8bitmime) {
4730 if (strcmpic(value, US"8BITMIME") == 0)
4732 else if (strcmpic(value, US"7BIT") == 0)
4737 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4738 US"invalid data for BODY");
4741 DEBUG(D_receive) debug_printf("8BITMIME: %d\n", body_8bitmime);
4747 /* Handle the two DSN options, but only if configured to do so (which
4748 will have caused "DSN" to be given in the EHLO response). The code itself
4749 is included only if configured in at build time. */
4751 case ENV_MAIL_OPT_RET:
4752 if (fl.dsn_advertised)
4754 /* Check if RET has already been set */
4757 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4758 US"RET can be specified once only");
4761 dsn_ret = strcmpic(value, US"HDRS") == 0
4763 : strcmpic(value, US"FULL") == 0
4766 DEBUG(D_receive) debug_printf("DSN_RET: %d\n", dsn_ret);
4767 /* Check for invalid invalid value, and exit with error */
4770 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4771 US"Value for RET is invalid");
4776 case ENV_MAIL_OPT_ENVID:
4777 if (fl.dsn_advertised)
4779 /* Check if the dsn envid has been already set */
4782 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4783 US"ENVID can be specified once only");
4786 dsn_envid = string_copy(value);
4787 DEBUG(D_receive) debug_printf("DSN_ENVID: %s\n", dsn_envid);
4791 /* Handle the AUTH extension. If the value given is not "<>" and either
4792 the ACL says "yes" or there is no ACL but the sending host is
4793 authenticated, we set it up as the authenticated sender. However, if the
4794 authenticator set a condition to be tested, we ignore AUTH on MAIL unless
4795 the condition is met. The value of AUTH is an xtext, which means that +,
4796 = and cntrl chars are coded in hex; however "<>" is unaffected by this
4798 case ENV_MAIL_OPT_AUTH:
4799 if (Ustrcmp(value, "<>") != 0)
4804 if (auth_xtextdecode(value, &authenticated_sender) < 0)
4806 /* Put back terminator overrides for error message */
4809 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4810 US"invalid data for AUTH");
4813 if (!acl_smtp_mailauth)
4815 ignore_msg = US"client not authenticated";
4816 rc = sender_host_authenticated ? OK : FAIL;
4820 ignore_msg = US"rejected by ACL";
4821 rc = acl_check(ACL_WHERE_MAILAUTH, NULL, acl_smtp_mailauth,
4822 &user_msg, &log_msg);
4828 if (authenticated_by == NULL ||
4829 authenticated_by->mail_auth_condition == NULL ||
4830 expand_check_condition(authenticated_by->mail_auth_condition,
4831 authenticated_by->name, US"authenticator"))
4832 break; /* Accept the AUTH */
4834 ignore_msg = US"server_mail_auth_condition failed";
4835 if (authenticated_id != NULL)
4836 ignore_msg = string_sprintf("%s: authenticated ID=\"%s\"",
4837 ignore_msg, authenticated_id);
4842 authenticated_sender = NULL;
4843 log_write(0, LOG_MAIN, "ignoring AUTH=%s from %s (%s)",
4844 value, host_and_ident(TRUE), ignore_msg);
4847 /* Should only get DEFER or ERROR here. Put back terminator
4848 overrides for error message */
4853 (void)smtp_handle_acl_fail(ACL_WHERE_MAILAUTH, rc, user_msg,
4860 #ifndef DISABLE_PRDR
4861 case ENV_MAIL_OPT_PRDR:
4863 prdr_requested = TRUE;
4868 case ENV_MAIL_OPT_UTF8:
4869 if (!fl.smtputf8_advertised)
4871 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4872 US"SMTPUTF8 used when not advertised");
4876 DEBUG(D_receive) debug_printf("smtputf8 requested\n");
4877 message_smtputf8 = allow_utf8_domains = TRUE;
4878 if (Ustrncmp(received_protocol, US"utf8", 4) != 0)
4880 int old_pool = store_pool;
4881 store_pool = POOL_PERM;
4882 received_protocol = string_sprintf("utf8%s", received_protocol);
4883 store_pool = old_pool;
4888 /* No valid option. Stick back the terminator characters and break
4889 the loop. Do the name-terminator second as extract_option sets
4890 value==name when it found no equal-sign.
4891 An error for a malformed address will occur. */
4892 case ENV_MAIL_OPT_NULL:
4900 /* Break out of for loop if switch() had bad argument or
4901 when start of the email address is reached */
4902 if (arg_error) break;
4905 /* If we have passed the threshold for rate limiting, apply the current
4906 delay, and update it for next time, provided this is a limited host. */
4908 if (smtp_mailcmd_count > smtp_rlm_threshold &&
4909 verify_check_host(&smtp_ratelimit_hosts) == OK)
4911 DEBUG(D_receive) debug_printf("rate limit MAIL: delay %.3g sec\n",
4912 smtp_delay_mail/1000.0);
4913 millisleep((int)smtp_delay_mail);
4914 smtp_delay_mail *= smtp_rlm_factor;
4915 if (smtp_delay_mail > (double)smtp_rlm_limit)
4916 smtp_delay_mail = (double)smtp_rlm_limit;
4919 /* Now extract the address, first applying any SMTP-time rewriting. The
4920 TRUE flag allows "<>" as a sender address. */
4922 raw_sender = rewrite_existflags & rewrite_smtp
4923 /* deconst ok as smtp_cmd_data was not const */
4924 ? US rewrite_one(smtp_cmd_data, rewrite_smtp, NULL, FALSE, US"",
4925 global_rewrite_rules)
4929 parse_extract_address(raw_sender, &errmess, &start, &end, &sender_domain,
4934 done = synprot_error(L_smtp_syntax_error, 501, smtp_cmd_data, errmess);
4938 sender_address = raw_sender;
4940 /* If there is a configured size limit for mail, check that this message
4941 doesn't exceed it. The check is postponed to this point so that the sender
4944 if (thismessage_size_limit > 0 && message_size > thismessage_size_limit)
4946 smtp_printf("552 Message size exceeds maximum permitted\r\n", FALSE);
4947 log_write(L_size_reject,
4948 LOG_MAIN|LOG_REJECT, "rejected MAIL FROM:<%s> %s: "
4949 "message too big: size%s=%d max=%d",
4951 host_and_ident(TRUE),
4952 (message_size == INT_MAX)? ">" : "",
4954 thismessage_size_limit);
4955 sender_address = NULL;
4959 /* Check there is enough space on the disk unless configured not to.
4960 When smtp_check_spool_space is set, the check is for thismessage_size_limit
4961 plus the current message - i.e. we accept the message only if it won't
4962 reduce the space below the threshold. Add 5000 to the size to allow for
4963 overheads such as the Received: line and storing of recipients, etc.
4964 By putting the check here, even when SIZE is not given, it allow VRFY
4965 and EXPN etc. to be used when space is short. */
4967 if (!receive_check_fs(
4968 smtp_check_spool_space && message_size >= 0
4969 ? message_size + 5000 : 0))
4971 smtp_printf("452 Space shortage, please try later\r\n", FALSE);
4972 sender_address = NULL;
4976 /* If sender_address is unqualified, reject it, unless this is a locally
4977 generated message, or the sending host or net is permitted to send
4978 unqualified addresses - typically local machines behaving as MUAs -
4979 in which case just qualify the address. The flag is set above at the start
4980 of the SMTP connection. */
4982 if (!sender_domain && *sender_address)
4983 if (f.allow_unqualified_sender)
4985 sender_domain = Ustrlen(sender_address) + 1;
4986 /* deconst ok as sender_address was not const */
4987 sender_address = US rewrite_address_qualify(sender_address, FALSE);
4988 DEBUG(D_receive) debug_printf("unqualified address %s accepted\n",
4993 smtp_printf("501 %s: sender address must contain a domain\r\n", FALSE,
4995 log_write(L_smtp_syntax_error,
4996 LOG_MAIN|LOG_REJECT,
4997 "unqualified sender rejected: <%s> %s%s",
4999 host_and_ident(TRUE),
5001 sender_address = NULL;
5005 /* Apply an ACL check if one is defined, before responding. Afterwards,
5006 when pipelining is not advertised, do another sync check in case the ACL
5007 delayed and the client started sending in the meantime. */
5011 rc = acl_check(ACL_WHERE_MAIL, NULL, acl_smtp_mail, &user_msg, &log_msg);
5012 if (rc == OK && !f.smtp_in_pipelining_advertised && !check_sync())
5018 if (rc == OK || rc == DISCARD)
5020 BOOL more = pipeline_response();
5023 smtp_printf("%s%s%s", more, US"250 OK",
5024 #ifndef DISABLE_PRDR
5025 prdr_requested ? US", PRDR Requested" : US"",
5032 #ifndef DISABLE_PRDR
5034 user_msg = string_sprintf("%s%s", user_msg, US", PRDR Requested");
5036 smtp_user_msg(US"250", user_msg);
5038 smtp_delay_rcpt = smtp_rlr_base;
5039 f.recipients_discarded = (rc == DISCARD);
5040 was_rej_mail = FALSE;
5044 done = smtp_handle_acl_fail(ACL_WHERE_MAIL, rc, user_msg, log_msg);
5045 sender_address = NULL;
5050 /* The RCPT command requires an address as an operand. There may be any
5051 number of RCPT commands, specifying multiple recipients. We build them all
5052 into a data structure. The start/end values given by parse_extract_address
5053 are not used, as we keep only the extracted address. */
5057 /* We got really to many recipients. A check against configured
5058 limits is done later */
5059 if (rcpt_count < 0 || rcpt_count >= INT_MAX/2)
5060 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "Too many recipients: %d", rcpt_count);
5062 was_rcpt = fl.rcpt_in_progress = TRUE;
5064 /* There must be a sender address; if the sender was rejected and
5065 pipelining was advertised, we assume the client was pipelining, and do not
5066 count this as a protocol error. Reset was_rej_mail so that further RCPTs
5067 get the same treatment. */
5069 if (sender_address == NULL)
5071 if (f.smtp_in_pipelining_advertised && last_was_rej_mail)
5073 smtp_printf("503 sender not yet given\r\n", FALSE);
5074 was_rej_mail = TRUE;
5078 done = synprot_error(L_smtp_protocol_error, 503, NULL,
5079 US"sender not yet given");
5080 was_rcpt = FALSE; /* Not a valid RCPT */
5086 /* Check for an operand */
5088 if (smtp_cmd_data[0] == 0)
5090 done = synprot_error(L_smtp_syntax_error, 501, NULL,
5091 US"RCPT must have an address operand");
5096 /* Set the DSN flags orcpt and dsn_flags from the session*/
5100 if (fl.esmtp) for(;;)
5102 uschar *name, *value;
5104 if (!extract_option(&name, &value))
5107 if (fl.dsn_advertised && strcmpic(name, US"ORCPT") == 0)
5109 /* Check whether orcpt has been already set */
5112 done = synprot_error(L_smtp_syntax_error, 501, NULL,
5113 US"ORCPT can be specified once only");
5116 orcpt = string_copy(value);
5117 DEBUG(D_receive) debug_printf("DSN orcpt: %s\n", orcpt);
5120 else if (fl.dsn_advertised && strcmpic(name, US"NOTIFY") == 0)
5122 /* Check if the notify flags have been already set */
5125 done = synprot_error(L_smtp_syntax_error, 501, NULL,
5126 US"NOTIFY can be specified once only");
5129 if (strcmpic(value, US"NEVER") == 0)
5130 dsn_flags |= rf_notify_never;
5137 while (*pp != 0 && *pp != ',') pp++;
5138 if (*pp == ',') *pp++ = 0;
5139 if (strcmpic(p, US"SUCCESS") == 0)
5141 DEBUG(D_receive) debug_printf("DSN: Setting notify success\n");
5142 dsn_flags |= rf_notify_success;
5144 else if (strcmpic(p, US"FAILURE") == 0)
5146 DEBUG(D_receive) debug_printf("DSN: Setting notify failure\n");
5147 dsn_flags |= rf_notify_failure;
5149 else if (strcmpic(p, US"DELAY") == 0)
5151 DEBUG(D_receive) debug_printf("DSN: Setting notify delay\n");
5152 dsn_flags |= rf_notify_delay;
5156 /* Catch any strange values */
5157 done = synprot_error(L_smtp_syntax_error, 501, NULL,
5158 US"Invalid value for NOTIFY parameter");
5163 DEBUG(D_receive) debug_printf("DSN Flags: %x\n", dsn_flags);
5167 /* Unknown option. Stick back the terminator characters and break
5168 the loop. An error for a malformed address will occur. */
5172 DEBUG(D_receive) debug_printf("Invalid RCPT option: %s : %s\n", name, value);
5179 /* Apply SMTP rewriting then extract the working address. Don't allow "<>"
5180 as a recipient address */
5182 recipient = rewrite_existflags & rewrite_smtp
5183 /* deconst ok as smtp_cmd_data was not const */
5184 ? US rewrite_one(smtp_cmd_data, rewrite_smtp, NULL, FALSE, US"",
5185 global_rewrite_rules)
5188 if (!(recipient = parse_extract_address(recipient, &errmess, &start, &end,
5189 &recipient_domain, FALSE)))
5191 done = synprot_error(L_smtp_syntax_error, 501, smtp_cmd_data, errmess);
5196 /* If the recipient address is unqualified, reject it, unless this is a
5197 locally generated message. However, unqualified addresses are permitted
5198 from a configured list of hosts and nets - typically when behaving as
5199 MUAs rather than MTAs. Sad that SMTP is used for both types of traffic,
5200 really. The flag is set at the start of the SMTP connection.
5202 RFC 1123 talks about supporting "the reserved mailbox postmaster"; I always
5203 assumed this meant "reserved local part", but the revision of RFC 821 and
5204 friends now makes it absolutely clear that it means *mailbox*. Consequently
5205 we must always qualify this address, regardless. */
5207 if (!recipient_domain)
5208 if (!(recipient_domain = qualify_recipient(&recipient, smtp_cmd_data,
5215 /* Check maximum allowed */
5217 if (rcpt_count+1 < 0 || rcpt_count > recipients_max && recipients_max > 0)
5219 if (recipients_max_reject)
5222 smtp_printf("552 too many recipients\r\n", FALSE);
5224 log_write(0, LOG_MAIN|LOG_REJECT, "too many recipients: message "
5225 "rejected: sender=<%s> %s", sender_address, host_and_ident(TRUE));
5230 smtp_printf("452 too many recipients\r\n", FALSE);
5232 log_write(0, LOG_MAIN|LOG_REJECT, "too many recipients: excess "
5233 "temporarily rejected: sender=<%s> %s", sender_address,
5234 host_and_ident(TRUE));
5241 /* If we have passed the threshold for rate limiting, apply the current
5242 delay, and update it for next time, provided this is a limited host. */
5244 if (rcpt_count > smtp_rlr_threshold &&
5245 verify_check_host(&smtp_ratelimit_hosts) == OK)
5247 DEBUG(D_receive) debug_printf("rate limit RCPT: delay %.3g sec\n",
5248 smtp_delay_rcpt/1000.0);
5249 millisleep((int)smtp_delay_rcpt);
5250 smtp_delay_rcpt *= smtp_rlr_factor;
5251 if (smtp_delay_rcpt > (double)smtp_rlr_limit)
5252 smtp_delay_rcpt = (double)smtp_rlr_limit;
5255 /* If the MAIL ACL discarded all the recipients, we bypass ACL checking
5256 for them. Otherwise, check the access control list for this recipient. As
5257 there may be a delay in this, re-check for a synchronization error
5258 afterwards, unless pipelining was advertised. */
5260 if (f.recipients_discarded)
5263 if ( (rc = acl_check(ACL_WHERE_RCPT, recipient, acl_smtp_rcpt, &user_msg,
5265 && !f.smtp_in_pipelining_advertised && !check_sync())
5268 /* The ACL was happy */
5272 BOOL more = pipeline_response();
5275 smtp_user_msg(US"250", user_msg);
5277 smtp_printf("250 Accepted\r\n", more);
5278 receive_add_recipient(recipient, -1);
5280 /* Set the dsn flags in the recipients_list */
5281 recipients_list[recipients_count-1].orcpt = orcpt;
5282 recipients_list[recipients_count-1].dsn_flags = dsn_flags;
5284 /* DEBUG(D_receive) debug_printf("DSN: orcpt: %s flags: %d\n",
5285 recipients_list[recipients_count-1].orcpt,
5286 recipients_list[recipients_count-1].dsn_flags); */
5289 /* The recipient was discarded */
5291 else if (rc == DISCARD)
5294 smtp_user_msg(US"250", user_msg);
5296 smtp_printf("250 Accepted\r\n", FALSE);
5299 log_write(0, LOG_MAIN|LOG_REJECT, "%s F=<%s> RCPT %s: "
5300 "discarded by %s ACL%s%s", host_and_ident(TRUE),
5301 sender_address_unrewritten ? sender_address_unrewritten : sender_address,
5302 smtp_cmd_argument, f.recipients_discarded ? "MAIL" : "RCPT",
5303 log_msg ? US": " : US"", log_msg ? log_msg : US"");
5306 /* Either the ACL failed the address, or it was deferred. */
5310 if (rc == FAIL) rcpt_fail_count++; else rcpt_defer_count++;
5311 done = smtp_handle_acl_fail(ACL_WHERE_RCPT, rc, user_msg, log_msg);
5316 /* The DATA command is legal only if it follows successful MAIL FROM
5317 and RCPT TO commands. However, if pipelining is advertised, a bad DATA is
5318 not counted as a protocol error if it follows RCPT (which must have been
5319 rejected if there are no recipients.) This function is complete when a
5320 valid DATA command is encountered.
5322 Note concerning the code used: RFC 2821 says this:
5324 - If there was no MAIL, or no RCPT, command, or all such commands
5325 were rejected, the server MAY return a "command out of sequence"
5326 (503) or "no valid recipients" (554) reply in response to the
5329 The example in the pipelining RFC 2920 uses 554, but I use 503 here
5330 because it is the same whether pipelining is in use or not.
5332 If all the RCPT commands that precede DATA provoked the same error message
5333 (often indicating some kind of system error), it is helpful to include it
5334 with the DATA rejection (an idea suggested by Tony Finch). */
5341 if (chunking_state != CHUNKING_OFFERED)
5343 done = synprot_error(L_smtp_protocol_error, 503, NULL,
5344 US"BDAT command used when CHUNKING not advertised");
5348 /* grab size, endmarker */
5350 if (sscanf(CS smtp_cmd_data, "%u %n", &chunking_datasize, &n) < 1)
5352 done = synprot_error(L_smtp_protocol_error, 501, NULL,
5353 US"missing size for BDAT command");
5356 chunking_state = strcmpic(smtp_cmd_data+n, US"LAST") == 0
5357 ? CHUNKING_LAST : CHUNKING_ACTIVE;
5358 chunking_data_left = chunking_datasize;
5359 DEBUG(D_receive) debug_printf("chunking state %d, %d bytes\n",
5360 (int)chunking_state, chunking_data_left);
5362 f.bdat_readers_wanted = TRUE; /* FIXME: redundant vs chunking_state? */
5371 f.bdat_readers_wanted = FALSE;
5373 DATA_BDAT: /* Common code for DATA and BDAT */
5374 #ifndef DISABLE_PIPE_CONNECT
5375 fl.pipe_connect_acceptable = FALSE;
5377 if (!discarded && recipients_count <= 0)
5379 if (fl.rcpt_smtp_response_same && rcpt_smtp_response != NULL)
5381 uschar *code = US"503";
5382 int len = Ustrlen(rcpt_smtp_response);
5383 smtp_respond(code, 3, FALSE, US"All RCPT commands were rejected with "
5385 /* Responses from smtp_printf() will have \r\n on the end */
5386 if (len > 2 && rcpt_smtp_response[len-2] == '\r')
5387 rcpt_smtp_response[len-2] = 0;
5388 smtp_respond(code, 3, FALSE, rcpt_smtp_response);
5390 if (f.smtp_in_pipelining_advertised && last_was_rcpt)
5391 smtp_printf("503 Valid RCPT command must precede %s\r\n", FALSE,
5392 smtp_names[smtp_connection_had[SMTP_HBUFF_PREV(smtp_ch_index)]]);
5394 done = synprot_error(L_smtp_protocol_error, 503, NULL,
5395 smtp_connection_had[SMTP_HBUFF_PREV(smtp_ch_index)] == SCH_DATA
5396 ? US"valid RCPT command must precede DATA"
5397 : US"valid RCPT command must precede BDAT");
5399 if (chunking_state > CHUNKING_OFFERED)
5401 bdat_push_receive_functions();
5407 if (toomany && recipients_max_reject)
5409 sender_address = NULL; /* This will allow a new MAIL without RSET */
5410 sender_address_unrewritten = NULL;
5411 smtp_printf("554 Too many recipients\r\n", FALSE);
5413 if (chunking_state > CHUNKING_OFFERED)
5415 bdat_push_receive_functions();
5421 if (chunking_state > CHUNKING_OFFERED)
5422 rc = OK; /* No predata ACL or go-ahead output for BDAT */
5425 /* If there is an ACL, re-check the synchronization afterwards, since the
5426 ACL may have delayed. To handle cutthrough delivery enforce a dummy call
5427 to get the DATA command sent. */
5429 if (acl_smtp_predata == NULL && cutthrough.cctx.sock < 0)
5433 uschar * acl = acl_smtp_predata ? acl_smtp_predata : US"accept";
5434 f.enable_dollar_recipients = TRUE;
5435 rc = acl_check(ACL_WHERE_PREDATA, NULL, acl, &user_msg,
5437 f.enable_dollar_recipients = FALSE;
5438 if (rc == OK && !check_sync())
5442 { /* Either the ACL failed the address, or it was deferred. */
5443 done = smtp_handle_acl_fail(ACL_WHERE_PREDATA, rc, user_msg, log_msg);
5449 smtp_user_msg(US"354", user_msg);
5452 "354 Enter message, ending with \".\" on a line by itself\r\n", FALSE);
5455 if (f.bdat_readers_wanted)
5456 bdat_push_receive_functions();
5459 if (smtp_in) /* all ACKs needed to ramp window up for bulk data */
5460 (void) setsockopt(fileno(smtp_in), IPPROTO_TCP, TCP_QUICKACK,
5461 US &on, sizeof(on));
5464 message_ended = END_NOTENDED; /* Indicate in middle of data */
5475 if (!(address = parse_extract_address(smtp_cmd_data, &errmess,
5476 &start, &end, &recipient_domain, FALSE)))
5478 smtp_printf("501 %s\r\n", FALSE, errmess);
5482 if (!recipient_domain)
5483 if (!(recipient_domain = qualify_recipient(&address, smtp_cmd_data,
5487 if ((rc = acl_check(ACL_WHERE_VRFY, address, acl_smtp_vrfy,
5488 &user_msg, &log_msg)) != OK)
5489 done = smtp_handle_acl_fail(ACL_WHERE_VRFY, rc, user_msg, log_msg);
5493 address_item * addr = deliver_make_addr(address, FALSE);
5495 switch(verify_address(addr, NULL, vopt_is_recipient | vopt_qualify, -1,
5496 -1, -1, NULL, NULL, NULL))
5499 s = string_sprintf("250 <%s> is deliverable", address);
5503 s = (addr->user_message != NULL)?
5504 string_sprintf("451 <%s> %s", address, addr->user_message) :
5505 string_sprintf("451 Cannot resolve <%s> at this time", address);
5509 s = (addr->user_message != NULL)?
5510 string_sprintf("550 <%s> %s", address, addr->user_message) :
5511 string_sprintf("550 <%s> is not deliverable", address);
5512 log_write(0, LOG_MAIN, "VRFY failed for %s %s",
5513 smtp_cmd_argument, host_and_ident(TRUE));
5517 smtp_printf("%s\r\n", FALSE, s);
5525 rc = acl_check(ACL_WHERE_EXPN, NULL, acl_smtp_expn, &user_msg, &log_msg);
5527 done = smtp_handle_acl_fail(ACL_WHERE_EXPN, rc, user_msg, log_msg);
5530 BOOL save_log_testing_mode = f.log_testing_mode;
5531 f.address_test_mode = f.log_testing_mode = TRUE;
5532 (void) verify_address(deliver_make_addr(smtp_cmd_data, FALSE),
5533 smtp_out, vopt_is_recipient | vopt_qualify | vopt_expn, -1, -1, -1,
5535 f.address_test_mode = FALSE;
5536 f.log_testing_mode = save_log_testing_mode; /* true for -bh */
5545 if (!fl.tls_advertised)
5547 done = synprot_error(L_smtp_protocol_error, 503, NULL,
5548 US"STARTTLS command used when not advertised");
5552 /* Apply an ACL check if one is defined */
5554 if ( acl_smtp_starttls
5555 && (rc = acl_check(ACL_WHERE_STARTTLS, NULL, acl_smtp_starttls,
5556 &user_msg, &log_msg)) != OK
5559 done = smtp_handle_acl_fail(ACL_WHERE_STARTTLS, rc, user_msg, log_msg);
5563 /* RFC 2487 is not clear on when this command may be sent, though it
5564 does state that all information previously obtained from the client
5565 must be discarded if a TLS session is started. It seems reasonable to
5566 do an implied RSET when STARTTLS is received. */
5568 incomplete_transaction_log(US"STARTTLS");
5569 cancel_cutthrough_connection(TRUE, US"STARTTLS received");
5570 reset_point = smtp_reset(reset_point);
5572 cmd_list[CMD_LIST_STARTTLS].is_mail_cmd = FALSE;
5574 /* There's an attack where more data is read in past the STARTTLS command
5575 before TLS is negotiated, then assumed to be part of the secure session
5576 when used afterwards; we use segregated input buffers, so are not
5577 vulnerable, but we want to note when it happens and, for sheer paranoia,
5578 ensure that the buffer is "wiped".
5579 Pipelining sync checks will normally have protected us too, unless disabled
5580 by configuration. */
5582 if (receive_smtp_buffered())
5585 debug_printf("Non-empty input buffer after STARTTLS; naive attack?\n");
5586 if (tls_in.active.sock < 0)
5587 smtp_inend = smtp_inptr = smtp_inbuffer;
5588 /* and if TLS is already active, tls_server_start() should fail */
5591 /* There is nothing we value in the input buffer and if TLS is successfully
5592 negotiated, we won't use this buffer again; if TLS fails, we'll just read
5593 fresh content into it. The buffer contains arbitrary content from an
5594 untrusted remote source; eg: NOOP <shellcode>\r\nSTARTTLS\r\n
5595 It seems safest to just wipe away the content rather than leave it as a
5596 target to jump to. */
5598 memset(smtp_inbuffer, 0, IN_BUFFER_SIZE);
5600 /* Attempt to start up a TLS session, and if successful, discard all
5601 knowledge that was obtained previously. At least, that's what the RFC says,
5602 and that's what happens by default. However, in order to work round YAEB,
5603 there is an option to remember the esmtp state. Sigh.
5605 We must allow for an extra EHLO command and an extra AUTH command after
5606 STARTTLS that don't add to the nonmail command count. */
5609 if ((rc = tls_server_start(&s)) == OK)
5611 if (!tls_remember_esmtp)
5612 fl.helo_seen = fl.esmtp = fl.auth_advertised = f.smtp_in_pipelining_advertised = FALSE;
5613 cmd_list[CMD_LIST_EHLO].is_mail_cmd = TRUE;
5614 cmd_list[CMD_LIST_AUTH].is_mail_cmd = TRUE;
5615 cmd_list[CMD_LIST_TLS_AUTH].is_mail_cmd = TRUE;
5616 if (sender_helo_name)
5618 sender_helo_name = NULL;
5619 host_build_sender_fullhost(); /* Rebuild */
5620 set_process_info("handling incoming TLS connection from %s",
5621 host_and_ident(FALSE));
5624 (sender_host_address ? protocols : protocols_local)
5626 ? pextend + (sender_host_authenticated ? pauthed : 0)
5628 + (tls_in.active.sock >= 0 ? pcrpted : 0)
5631 sender_host_auth_pubname = sender_host_authenticated = NULL;
5632 authenticated_id = NULL;
5633 sync_cmd_limit = NON_SYNC_CMD_NON_PIPELINING;
5634 DEBUG(D_tls) debug_printf("TLS active\n");
5635 break; /* Successful STARTTLS */
5638 (void) smtp_log_tls_fail(s);
5640 /* Some local configuration problem was discovered before actually trying
5641 to do a TLS handshake; give a temporary error. */
5645 smtp_printf("454 TLS currently unavailable\r\n", FALSE);
5649 /* Hard failure. Reject everything except QUIT or closed connection. One
5650 cause for failure is a nested STARTTLS, in which case tls_in.active remains
5651 set, but we must still reject all incoming commands. Another is a handshake
5652 failure - and there may some encrypted data still in the pipe to us, which we
5653 see as garbage commands. */
5655 DEBUG(D_tls) debug_printf("TLS failed to start\n");
5656 while (done <= 0) switch(smtp_read_command(FALSE, GETC_BUFFER_UNLIMITED))
5659 log_write(L_smtp_connection, LOG_MAIN, "%s closed by EOF",
5660 smtp_get_connection_info());
5661 smtp_notquit_exit(US"tls-failed", NULL, NULL);
5665 /* It is perhaps arguable as to which exit ACL should be called here,
5666 but as it is probably a situation that almost never arises, it
5667 probably doesn't matter. We choose to call the real QUIT ACL, which in
5668 some sense is perhaps "right". */
5671 f.smtp_in_quit = TRUE;
5674 && ((rc = acl_check(ACL_WHERE_QUIT, NULL, acl_smtp_quit, &user_msg,
5675 &log_msg)) == ERROR))
5676 log_write(0, LOG_MAIN|LOG_PANIC, "ACL for QUIT returned ERROR: %s",
5679 smtp_respond(US"221", 3, TRUE, user_msg);
5681 smtp_printf("221 %s closing connection\r\n", FALSE, smtp_active_hostname);
5682 log_write(L_smtp_connection, LOG_MAIN, "%s closed by QUIT",
5683 smtp_get_connection_info());
5688 smtp_printf("554 Security failure\r\n", FALSE);
5691 tls_close(NULL, TLS_SHUTDOWN_NOWAIT);
5696 /* The ACL for QUIT is provided for gathering statistical information or
5697 similar; it does not affect the response code, but it can supply a custom
5701 smtp_quit_handler(&user_msg, &log_msg);
5707 smtp_rset_handler();
5708 cancel_cutthrough_connection(TRUE, US"RSET received");
5709 reset_point = smtp_reset(reset_point);
5716 smtp_printf("250 OK\r\n", FALSE);
5720 /* Show ETRN/EXPN/VRFY if there's an ACL for checking hosts; if actually
5721 used, a check will be done for permitted hosts. Show STARTTLS only if not
5722 already in a TLS session and if it would be advertised in the EHLO
5727 smtp_printf("214-Commands supported:\r\n", TRUE);
5731 Ustrcat(buffer, US" AUTH");
5733 if (tls_in.active.sock < 0 &&
5734 verify_check_host(&tls_advertise_hosts) != FAIL)
5735 Ustrcat(buffer, US" STARTTLS");
5737 Ustrcat(buffer, US" HELO EHLO MAIL RCPT DATA BDAT");
5738 Ustrcat(buffer, US" NOOP QUIT RSET HELP");
5739 if (acl_smtp_etrn) Ustrcat(buffer, US" ETRN");
5740 if (acl_smtp_expn) Ustrcat(buffer, US" EXPN");
5741 if (acl_smtp_vrfy) Ustrcat(buffer, US" VRFY");
5742 smtp_printf("214%s\r\n", FALSE, buffer);
5748 incomplete_transaction_log(US"connection lost");
5749 smtp_notquit_exit(US"connection-lost", US"421",
5750 US"%s lost input connection", smtp_active_hostname);
5752 /* Don't log by default unless in the middle of a message, as some mailers
5753 just drop the call rather than sending QUIT, and it clutters up the logs.
5756 if (sender_address || recipients_count > 0)
5757 log_write(L_lost_incoming_connection, LOG_MAIN,
5758 "unexpected %s while reading SMTP command from %s%s%s D=%s",
5759 f.sender_host_unknown ? "EOF" : "disconnection",
5760 f.tcp_in_fastopen_logged
5763 ? f.tcp_in_fastopen_data ? US"TFO* " : US"TFO "
5765 host_and_ident(FALSE), smtp_read_error,
5766 string_timesince(&smtp_connection_start)
5770 log_write(L_smtp_connection, LOG_MAIN, "%s %slost%s D=%s",
5771 smtp_get_connection_info(),
5772 f.tcp_in_fastopen && !f.tcp_in_fastopen_logged ? US"TFO " : US"",
5774 string_timesince(&smtp_connection_start)
5785 done = synprot_error(L_smtp_protocol_error, 503, NULL,
5786 US"ETRN is not permitted inside a transaction");
5790 log_write(L_etrn, LOG_MAIN, "ETRN %s received from %s", smtp_cmd_argument,
5791 host_and_ident(FALSE));
5793 if ((rc = acl_check(ACL_WHERE_ETRN, NULL, acl_smtp_etrn,
5794 &user_msg, &log_msg)) != OK)
5796 done = smtp_handle_acl_fail(ACL_WHERE_ETRN, rc, user_msg, log_msg);
5800 /* Compute the serialization key for this command. */
5802 etrn_serialize_key = string_sprintf("etrn-%s\n", smtp_cmd_data);
5804 /* If a command has been specified for running as a result of ETRN, we
5805 permit any argument to ETRN. If not, only the # standard form is permitted,
5806 since that is strictly the only kind of ETRN that can be implemented
5807 according to the RFC. */
5809 if (smtp_etrn_command)
5813 etrn_command = smtp_etrn_command;
5814 deliver_domain = smtp_cmd_data;
5815 rc = transport_set_up_command(&argv, smtp_etrn_command, TRUE, 0, NULL,
5816 US"ETRN processing", &error);
5817 deliver_domain = NULL;
5820 log_write(0, LOG_MAIN|LOG_PANIC, "failed to set up ETRN command: %s",
5822 smtp_printf("458 Internal failure\r\n", FALSE);
5827 /* Else set up to call Exim with the -R option. */
5831 if (*smtp_cmd_data++ != '#')
5833 done = synprot_error(L_smtp_syntax_error, 501, NULL,
5834 US"argument must begin with #");
5837 etrn_command = US"exim -R";
5838 argv = CUSS child_exec_exim(CEE_RETURN_ARGV, TRUE, NULL, TRUE,
5839 *queue_name ? 4 : 2,
5840 US"-R", smtp_cmd_data,
5841 US"-MCG", queue_name);
5844 /* If we are host-testing, don't actually do anything. */
5850 debug_printf("ETRN command is: %s\n", etrn_command);
5851 debug_printf("ETRN command execution skipped\n");
5853 if (user_msg == NULL) smtp_printf("250 OK\r\n", FALSE);
5854 else smtp_user_msg(US"250", user_msg);
5859 /* If ETRN queue runs are to be serialized, check the database to
5860 ensure one isn't already running. */
5862 if (smtp_etrn_serialize && !enq_start(etrn_serialize_key, 1))
5864 smtp_printf("458 Already processing %s\r\n", FALSE, smtp_cmd_data);
5868 /* Fork a child process and run the command. We don't want to have to
5869 wait for the process at any point, so set SIGCHLD to SIG_IGN before
5870 forking. It should be set that way anyway for external incoming SMTP,
5871 but we save and restore to be tidy. If serialization is required, we
5872 actually run the command in yet another process, so we can wait for it
5873 to complete and then remove the serialization lock. */
5875 oldsignal = signal(SIGCHLD, SIG_IGN);
5877 if ((pid = exim_fork(US"etrn-command")) == 0)
5879 smtp_input = FALSE; /* This process is not associated with the */
5880 (void)fclose(smtp_in); /* SMTP call any more. */
5881 (void)fclose(smtp_out);
5883 signal(SIGCHLD, SIG_DFL); /* Want to catch child */
5885 /* If not serializing, do the exec right away. Otherwise, fork down
5886 into another process. */
5888 if ( !smtp_etrn_serialize
5889 || (pid = exim_fork(US"etrn-serialised-command")) == 0)
5891 DEBUG(D_exec) debug_print_argv(argv);
5892 exim_nullstd(); /* Ensure std{in,out,err} exist */
5893 execv(CS argv[0], (char *const *)argv);
5894 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "exec of \"%s\" (ETRN) failed: %s",
5895 etrn_command, strerror(errno));
5896 _exit(EXIT_FAILURE); /* paranoia */
5899 /* Obey this if smtp_serialize and the 2nd fork yielded non-zero. That
5900 is, we are in the first subprocess, after forking again. All we can do
5901 for a failing fork is to log it. Otherwise, wait for the 2nd process to
5902 complete, before removing the serialization. */
5905 log_write(0, LOG_MAIN|LOG_PANIC, "2nd fork for serialized ETRN "
5906 "failed: %s", strerror(errno));
5910 DEBUG(D_any) debug_printf("waiting for serialized ETRN process %d\n",
5912 (void)wait(&status);
5913 DEBUG(D_any) debug_printf("serialized ETRN process %d ended\n",
5917 enq_end(etrn_serialize_key);
5918 exim_underbar_exit(EXIT_SUCCESS);
5921 /* Back in the top level SMTP process. Check that we started a subprocess
5922 and restore the signal state. */
5926 log_write(0, LOG_MAIN|LOG_PANIC, "fork of process for ETRN failed: %s",
5928 smtp_printf("458 Unable to fork process\r\n", FALSE);
5929 if (smtp_etrn_serialize) enq_end(etrn_serialize_key);
5933 smtp_printf("250 OK\r\n", FALSE);
5935 smtp_user_msg(US"250", user_msg);
5937 signal(SIGCHLD, oldsignal);
5942 done = synprot_error(L_smtp_syntax_error, 501, NULL,
5943 US"unexpected argument data");
5947 /* This currently happens only for NULLs, but could be extended. */
5950 done = synprot_error(L_smtp_syntax_error, 0, NULL, /* Just logs */
5951 US"NUL character(s) present (shown as '?')");
5952 smtp_printf("501 NUL characters are not allowed in SMTP commands\r\n",
5959 if (smtp_inend >= smtp_inbuffer + IN_BUFFER_SIZE)
5960 smtp_inend = smtp_inbuffer + IN_BUFFER_SIZE - 1;
5961 c = smtp_inend - smtp_inptr;
5962 if (c > 150) c = 150; /* limit logged amount */
5964 incomplete_transaction_log(US"sync failure");
5965 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP protocol synchronization error "
5966 "(next input sent too soon: pipelining was%s advertised): "
5967 "rejected \"%s\" %s next input=\"%s\"",
5968 f.smtp_in_pipelining_advertised ? "" : " not",
5969 smtp_cmd_buffer, host_and_ident(TRUE),
5970 string_printing(smtp_inptr));
5971 smtp_notquit_exit(US"synchronization-error", US"554",
5972 US"SMTP synchronization error");
5973 done = 1; /* Pretend eof - drops connection */
5977 case TOO_MANY_NONMAIL_CMD:
5978 s = smtp_cmd_buffer;
5979 while (*s != 0 && !isspace(*s)) s++;
5980 incomplete_transaction_log(US"too many non-mail commands");
5981 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
5982 "nonmail commands (last was \"%.*s\")", host_and_ident(FALSE),
5983 (int)(s - smtp_cmd_buffer), smtp_cmd_buffer);
5984 smtp_notquit_exit(US"bad-commands", US"554", US"Too many nonmail commands");
5985 done = 1; /* Pretend eof - drops connection */
5988 #ifdef SUPPORT_PROXY
5989 case PROXY_FAIL_IGNORE_CMD:
5990 smtp_printf("503 Command refused, required Proxy negotiation failed\r\n", FALSE);
5995 if (unknown_command_count++ >= smtp_max_unknown_commands)
5997 log_write(L_smtp_syntax_error, LOG_MAIN,
5998 "SMTP syntax error in \"%s\" %s %s",
5999 string_printing(smtp_cmd_buffer), host_and_ident(TRUE),
6000 US"unrecognized command");
6001 incomplete_transaction_log(US"unrecognized command");
6002 smtp_notquit_exit(US"bad-commands", US"500",
6003 US"Too many unrecognized commands");
6005 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
6006 "unrecognized commands (last was \"%s\")", host_and_ident(FALSE),
6007 string_printing(smtp_cmd_buffer));
6010 done = synprot_error(L_smtp_syntax_error, 500, NULL,
6011 US"unrecognized command");
6015 /* This label is used by goto's inside loops that want to break out to
6016 the end of the command-processing loop. */
6019 last_was_rej_mail = was_rej_mail; /* Remember some last commands for */
6020 last_was_rcpt = was_rcpt; /* protocol error handling */
6024 return done - 2; /* Convert yield values */
6030 authres_smtpauth(gstring * g)
6032 if (!sender_host_authenticated)
6035 g = string_append(g, 2, US";\n\tauth=pass (", sender_host_auth_pubname);
6037 if (Ustrcmp(sender_host_auth_pubname, "tls") == 0)
6038 g = authenticated_id
6039 ? string_append(g, 2, US") x509.auth=", authenticated_id)
6040 : string_cat(g, US") reason=x509.auth");
6042 g = authenticated_id
6043 ? string_append(g, 2, US") smtp.auth=", authenticated_id)
6044 : string_cat(g, US", no id saved)");
6046 if (authenticated_sender)
6047 g = string_append(g, 2, US" smtp.mailfrom=", authenticated_sender);
6055 /* End of smtp_in.c */