1 /*************************************************
2 * Exim - an Internet mail transport agent *
3 *************************************************/
5 /* Copyright (c) University of Cambridge 1995 - 2017 */
6 /* See the file NOTICE for conditions of use and distribution. */
8 /* Functions for handling an incoming SMTP call. */
15 /* Initialize for TCP wrappers if so configured. It appears that the macro
16 HAVE_IPV6 is used in some versions of the tcpd.h header, so we unset it before
17 including that header, and restore its value afterwards. */
19 #ifdef USE_TCP_WRAPPERS
22 #define EXIM_HAVE_IPV6
28 #define HAVE_IPV6 TRUE
31 int allow_severity = LOG_INFO;
32 int deny_severity = LOG_NOTICE;
33 uschar *tcp_wrappers_name;
37 /* Size of buffer for reading SMTP commands. We used to use 512, as defined
38 by RFC 821. However, RFC 1869 specifies that this must be increased for SMTP
39 commands that accept arguments, and this in particular applies to AUTH, where
40 the data can be quite long. More recently this value was 2048 in Exim;
41 however, RFC 4954 (circa 2007) recommends 12288 bytes to handle AUTH. Clients
42 such as Thunderbird will send an AUTH with an initial-response for GSSAPI.
43 The maximum size of a Kerberos ticket under Windows 2003 is 12000 bytes, and
44 we need room to handle large base64-encoded AUTHs for GSSAPI.
47 #define SMTP_CMD_BUFFER_SIZE 16384
49 /* Size of buffer for reading SMTP incoming packets */
51 #define IN_BUFFER_SIZE 8192
53 /* Structure for SMTP command list */
60 short int is_mail_cmd;
63 /* Codes for identifying commands. We order them so that those that come first
64 are those for which synchronization is always required. Checking this can help
68 /* These commands are required to be synchronized, i.e. to be the last in a
69 block of commands when pipelining. */
71 HELO_CMD, EHLO_CMD, DATA_CMD, /* These are listed in the pipelining */
72 VRFY_CMD, EXPN_CMD, NOOP_CMD, /* RFC as requiring synchronization */
73 ETRN_CMD, /* This by analogy with TURN from the RFC */
74 STARTTLS_CMD, /* Required by the STARTTLS RFC */
75 TLS_AUTH_CMD, /* auto-command at start of SSL */
77 /* This is a dummy to identify the non-sync commands when pipelining */
79 NON_SYNC_CMD_PIPELINING,
81 /* These commands need not be synchronized when pipelining */
83 MAIL_CMD, RCPT_CMD, RSET_CMD,
85 /* This is a dummy to identify the non-sync commands when not pipelining */
87 NON_SYNC_CMD_NON_PIPELINING,
89 /* RFC3030 section 2: "After all MAIL and RCPT responses are collected and
90 processed the message is sent using a series of BDAT commands"
91 implies that BDAT should be synchronized. However, we see Google, at least,
92 sending MAIL,RCPT,BDAT-LAST in a single packet, clearly not waiting for
93 processing of the RCPT response(s). We shall do the same, and not require
94 synch for BDAT. Worse, as the chunk may (very likely will) follow the
95 command-header in the same packet we cannot do the usual "is there any
96 follow-on data after the command line" even for non-pipeline mode.
97 So we'll need an explicit check after reading the expected chunk amount
98 when non-pipe, before sending the ACK. */
102 /* I have been unable to find a statement about the use of pipelining
103 with AUTH, so to be on the safe side it is here, though I kind of feel
104 it should be up there with the synchronized commands. */
108 /* I'm not sure about these, but I don't think they matter. */
113 PROXY_FAIL_IGNORE_CMD,
116 /* These are specials that don't correspond to actual commands */
118 EOF_CMD, OTHER_CMD, BADARG_CMD, BADCHAR_CMD, BADSYN_CMD,
119 TOO_MANY_NONMAIL_CMD };
122 /* This is a convenience macro for adding the identity of an SMTP command
123 to the circular buffer that holds a list of the last n received. */
126 smtp_connection_had[smtp_ch_index++] = n; \
127 if (smtp_ch_index >= SMTP_HBUFF_SIZE) smtp_ch_index = 0
130 /*************************************************
131 * Local static variables *
132 *************************************************/
134 static auth_instance *authenticated_by;
135 static BOOL auth_advertised;
137 static BOOL tls_advertised;
139 static BOOL dsn_advertised;
141 static BOOL helo_required = FALSE;
142 static BOOL helo_verify = FALSE;
143 static BOOL helo_seen;
144 static BOOL helo_accept_junk;
145 static BOOL count_nonmail;
146 static BOOL pipelining_advertised;
147 static BOOL rcpt_smtp_response_same;
148 static BOOL rcpt_in_progress;
149 static int nonmail_command_count;
150 static BOOL smtp_exit_function_called = 0;
152 static BOOL smtputf8_advertised;
154 static int synprot_error_count;
155 static int unknown_command_count;
156 static int sync_cmd_limit;
157 static int smtp_write_error = 0;
159 static uschar *rcpt_smtp_response;
160 static uschar *smtp_data_buffer;
161 static uschar *smtp_cmd_data;
163 /* We need to know the position of RSET, HELO, EHLO, AUTH, and STARTTLS. Their
164 final fields of all except AUTH are forced TRUE at the start of a new message
165 setup, to allow one of each between messages that is not counted as a nonmail
166 command. (In fact, only one of HELO/EHLO is not counted.) Also, we have to
167 allow a new EHLO after starting up TLS.
169 AUTH is "falsely" labelled as a mail command initially, so that it doesn't get
170 counted. However, the flag is changed when AUTH is received, so that multiple
171 failing AUTHs will eventually hit the limit. After a successful AUTH, another
172 AUTH is already forbidden. After a TLS session is started, AUTH's flag is again
173 forced TRUE, to allow for the re-authentication that can happen at that point.
175 QUIT is also "falsely" labelled as a mail command so that it doesn't up the
176 count of non-mail commands and possibly provoke an error.
178 tls_auth is a pseudo-command, never expected in input. It is activated
179 on TLS startup and looks for a tls authenticator. */
181 static smtp_cmd_list cmd_list[] = {
182 /* name len cmd has_arg is_mail_cmd */
184 { "rset", sizeof("rset")-1, RSET_CMD, FALSE, FALSE }, /* First */
185 { "helo", sizeof("helo")-1, HELO_CMD, TRUE, FALSE },
186 { "ehlo", sizeof("ehlo")-1, EHLO_CMD, TRUE, FALSE },
187 { "auth", sizeof("auth")-1, AUTH_CMD, TRUE, TRUE },
189 { "starttls", sizeof("starttls")-1, STARTTLS_CMD, FALSE, FALSE },
190 { "tls_auth", 0, TLS_AUTH_CMD, FALSE, TRUE },
193 /* If you change anything above here, also fix the definitions below. */
195 { "mail from:", sizeof("mail from:")-1, MAIL_CMD, TRUE, TRUE },
196 { "rcpt to:", sizeof("rcpt to:")-1, RCPT_CMD, TRUE, TRUE },
197 { "data", sizeof("data")-1, DATA_CMD, FALSE, TRUE },
198 { "bdat", sizeof("bdat")-1, BDAT_CMD, TRUE, TRUE },
199 { "quit", sizeof("quit")-1, QUIT_CMD, FALSE, TRUE },
200 { "noop", sizeof("noop")-1, NOOP_CMD, TRUE, FALSE },
201 { "etrn", sizeof("etrn")-1, ETRN_CMD, TRUE, FALSE },
202 { "vrfy", sizeof("vrfy")-1, VRFY_CMD, TRUE, FALSE },
203 { "expn", sizeof("expn")-1, EXPN_CMD, TRUE, FALSE },
204 { "help", sizeof("help")-1, HELP_CMD, TRUE, FALSE }
207 static smtp_cmd_list *cmd_list_end =
208 cmd_list + sizeof(cmd_list)/sizeof(smtp_cmd_list);
210 #define CMD_LIST_RSET 0
211 #define CMD_LIST_HELO 1
212 #define CMD_LIST_EHLO 2
213 #define CMD_LIST_AUTH 3
214 #define CMD_LIST_STARTTLS 4
215 #define CMD_LIST_TLS_AUTH 5
217 /* This list of names is used for performing the smtp_no_mail logging action.
218 It must be kept in step with the SCH_xxx enumerations. */
220 static uschar *smtp_names[] =
222 US"NONE", US"AUTH", US"DATA", US"BDAT", US"EHLO", US"ETRN", US"EXPN",
223 US"HELO", US"HELP", US"MAIL", US"NOOP", US"QUIT", US"RCPT", US"RSET",
224 US"STARTTLS", US"VRFY" };
226 static uschar *protocols_local[] = {
227 US"local-smtp", /* HELO */
228 US"local-smtps", /* The rare case EHLO->STARTTLS->HELO */
229 US"local-esmtp", /* EHLO */
230 US"local-esmtps", /* EHLO->STARTTLS->EHLO */
231 US"local-esmtpa", /* EHLO->AUTH */
232 US"local-esmtpsa" /* EHLO->STARTTLS->EHLO->AUTH */
234 static uschar *protocols[] = {
236 US"smtps", /* The rare case EHLO->STARTTLS->HELO */
237 US"esmtp", /* EHLO */
238 US"esmtps", /* EHLO->STARTTLS->EHLO */
239 US"esmtpa", /* EHLO->AUTH */
240 US"esmtpsa" /* EHLO->STARTTLS->EHLO->AUTH */
245 #define pcrpted 1 /* added to pextend or pnormal */
246 #define pauthed 2 /* added to pextend */
248 /* Sanity check and validate optional args to MAIL FROM: envelope */
251 ENV_MAIL_OPT_SIZE, ENV_MAIL_OPT_BODY, ENV_MAIL_OPT_AUTH,
255 ENV_MAIL_OPT_RET, ENV_MAIL_OPT_ENVID,
261 uschar * name; /* option requested during MAIL cmd */
262 int value; /* enum type */
263 BOOL need_value; /* TRUE requires value (name=value pair format)
264 FALSE is a singleton */
266 static env_mail_type_t env_mail_type_list[] = {
267 { US"SIZE", ENV_MAIL_OPT_SIZE, TRUE },
268 { US"BODY", ENV_MAIL_OPT_BODY, TRUE },
269 { US"AUTH", ENV_MAIL_OPT_AUTH, TRUE },
271 { US"PRDR", ENV_MAIL_OPT_PRDR, FALSE },
273 { US"RET", ENV_MAIL_OPT_RET, TRUE },
274 { US"ENVID", ENV_MAIL_OPT_ENVID, TRUE },
276 { US"SMTPUTF8",ENV_MAIL_OPT_UTF8, FALSE }, /* rfc6531 */
278 /* keep this the last entry */
279 { US"NULL", ENV_MAIL_OPT_NULL, FALSE },
282 /* When reading SMTP from a remote host, we have to use our own versions of the
283 C input-reading functions, in order to be able to flush the SMTP output only
284 when about to read more data from the socket. This is the only way to get
285 optimal performance when the client is using pipelining. Flushing for every
286 command causes a separate packet and reply packet each time; saving all the
287 responses up (when pipelining) combines them into one packet and one response.
289 For simplicity, these functions are used for *all* SMTP input, not only when
290 receiving over a socket. However, after setting up a secure socket (SSL), input
291 is read via the OpenSSL library, and another set of functions is used instead
294 These functions are set in the receive_getc etc. variables and called with the
295 same interface as the C functions. However, since there can only ever be
296 one incoming SMTP call, we just use a single buffer and flags. There is no need
297 to implement a complicated private FILE-like structure.*/
299 static uschar *smtp_inbuffer;
300 static uschar *smtp_inptr;
301 static uschar *smtp_inend;
302 static int smtp_had_eof;
303 static int smtp_had_error;
306 /* forward declarations */
307 int bdat_ungetc(int ch);
308 static int smtp_read_command(BOOL check_sync, unsigned buffer_lim);
309 static int synprot_error(int type, int code, uschar *data, uschar *errmess);
310 static void smtp_quit_handler(uschar **, uschar **);
311 static void smtp_rset_handler(void);
313 /*************************************************
314 * Recheck synchronization *
315 *************************************************/
317 /* Synchronization checks can never be perfect because a packet may be on its
318 way but not arrived when the check is done. Such checks can in any case only be
319 done when TLS is not in use. Normally, the checks happen when commands are
320 read: Exim ensures that there is no more input in the input buffer. In normal
321 cases, the response to the command will be fast, and there is no further check.
323 However, for some commands an ACL is run, and that can include delays. In those
324 cases, it is useful to do another check on the input just before sending the
325 response. This also applies at the start of a connection. This function does
326 that check by means of the select() function, as long as the facility is not
327 disabled or inappropriate. A failure of select() is ignored.
329 When there is unwanted input, we read it so that it appears in the log of the
333 Returns: TRUE if all is well; FALSE if there is input pending
341 struct timeval tzero;
343 if (!smtp_enforce_sync || sender_host_address == NULL ||
344 sender_host_notsocket || tls_in.active >= 0)
347 fd = fileno(smtp_in);
352 rc = select(fd + 1, (SELECT_ARG2_TYPE *)&fds, NULL, NULL, &tzero);
354 if (rc <= 0) return TRUE; /* Not ready to read */
355 rc = smtp_getc(GETC_BUFFER_UNLIMITED);
356 if (rc < 0) return TRUE; /* End of file or error */
359 rc = smtp_inend - smtp_inptr;
360 if (rc > 150) rc = 150;
367 /*************************************************
368 * Log incomplete transactions *
369 *************************************************/
371 /* This function is called after a transaction has been aborted by RSET, QUIT,
372 connection drops or other errors. It logs the envelope information received
373 so far in order to preserve address verification attempts.
375 Argument: string to indicate what aborted the transaction
380 incomplete_transaction_log(uschar *what)
382 if (sender_address == NULL || /* No transaction in progress */
383 !LOGGING(smtp_incomplete_transaction))
386 /* Build list of recipients for logging */
388 if (recipients_count > 0)
391 raw_recipients = store_get(recipients_count * sizeof(uschar *));
392 for (i = 0; i < recipients_count; i++)
393 raw_recipients[i] = recipients_list[i].address;
394 raw_recipients_count = recipients_count;
397 log_write(L_smtp_incomplete_transaction, LOG_MAIN|LOG_SENDER|LOG_RECIPIENTS,
398 "%s incomplete transaction (%s)", host_and_ident(TRUE), what);
404 /*************************************************
405 * SMTP version of getc() *
406 *************************************************/
408 /* This gets the next byte from the SMTP input buffer. If the buffer is empty,
409 it flushes the output, and refills the buffer, with a timeout. The signal
410 handler is set appropriately by the calling function. This function is not used
411 after a connection has negotiated itself into an TLS/SSL state.
413 Arguments: lim Maximum amount to read/buffer
414 Returns: the next character or EOF
418 smtp_getc(unsigned lim)
420 if (smtp_inptr >= smtp_inend)
423 if (!smtp_out) return EOF;
425 if (smtp_receive_timeout > 0) alarm(smtp_receive_timeout);
427 /* Limit amount read, so non-message data is not fed to DKIM */
429 rc = read(fileno(smtp_in), smtp_inbuffer, MIN(IN_BUFFER_SIZE, lim));
434 /* Must put the error text in fixed store, because this might be during
435 header reading, where it releases unused store above the header. */
438 smtp_had_error = save_errno;
439 smtp_read_error = string_copy_malloc(
440 string_sprintf(" (error: %s)", strerror(save_errno)));
442 else smtp_had_eof = 1;
446 dkim_exim_verify_feed(smtp_inbuffer, rc);
448 smtp_inend = smtp_inbuffer + rc;
449 smtp_inptr = smtp_inbuffer;
451 return *smtp_inptr++;
458 int n = smtp_inend - smtp_inptr;
460 dkim_exim_verify_feed(smtp_inptr, n);
465 /* Get a byte from the smtp input, in CHUNKING mode. Handle ack of the
466 previous BDAT chunk and getting new ones when we run out. Uses the
467 underlying smtp_getc or tls_getc both for that and for getting the
468 (buffered) data byte. EOD signals (an expected) no further data.
469 ERR signals a protocol error, and EOF a closed input stream.
471 Called from read_bdat_smtp() in receive.c for the message body, but also
472 by the headers read loop in receive_msg(); manipulates chunking_state
473 to handle the BDAT command/response.
474 Placed here due to the correlation with the above smtp_getc(), which it wraps,
475 and also by the need to do smtp command/response handling.
477 Arguments: lim (ignored)
478 Returns: the next character or ERR, EOD or EOF
482 bdat_getc(unsigned lim)
484 uschar * user_msg = NULL;
493 if (chunking_data_left > 0)
494 return lwr_receive_getc(chunking_data_left--);
496 receive_getc = lwr_receive_getc;
497 receive_ungetc = lwr_receive_ungetc;
499 dkim_save = dkim_collect_input;
500 dkim_collect_input = FALSE;
503 /* Unless PIPELINING was offered, there should be no next command
504 until after we ack that chunk */
506 if (!pipelining_advertised && !check_sync())
508 incomplete_transaction_log(US"sync failure");
509 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP protocol synchronization error "
510 "(next input sent too soon: pipelining was not advertised): "
511 "rejected \"%s\" %s next input=\"%s\"",
512 smtp_cmd_buffer, host_and_ident(TRUE),
513 string_printing(smtp_inptr));
514 (void) synprot_error(L_smtp_protocol_error, 554, NULL,
515 US"SMTP synchronization error");
516 goto repeat_until_rset;
519 /* If not the last, ack the received chunk. The last response is delayed
520 until after the data ACL decides on it */
522 if (chunking_state == CHUNKING_LAST)
525 dkim_exim_verify_feed(NULL, 0); /* notify EOD */
530 smtp_printf("250 %u byte chunk received\r\n", chunking_datasize);
531 chunking_state = CHUNKING_OFFERED;
532 DEBUG(D_receive) debug_printf("chunking state %d\n", (int)chunking_state);
534 /* Expect another BDAT cmd from input. RFC 3030 says nothing about
535 QUIT, RSET or NOOP but handling them seems obvious */
538 switch(smtp_read_command(TRUE, 1))
541 (void) synprot_error(L_smtp_protocol_error, 503, NULL,
542 US"only BDAT permissible after non-LAST BDAT");
545 switch(smtp_read_command(TRUE, 1))
547 case QUIT_CMD: smtp_quit_handler(&user_msg, &log_msg); /*FALLTHROUGH */
548 case EOF_CMD: return EOF;
549 case RSET_CMD: smtp_rset_handler(); return ERR;
550 default: if (synprot_error(L_smtp_protocol_error, 503, NULL,
551 US"only RSET accepted now") > 0)
553 goto repeat_until_rset;
557 smtp_quit_handler(&user_msg, &log_msg);
568 smtp_printf("250 OK\r\n");
575 if (sscanf(CS smtp_cmd_data, "%u %n", &chunking_datasize, &n) < 1)
577 (void) synprot_error(L_smtp_protocol_error, 501, NULL,
578 US"missing size for BDAT command");
581 chunking_state = strcmpic(smtp_cmd_data+n, US"LAST") == 0
582 ? CHUNKING_LAST : CHUNKING_ACTIVE;
583 chunking_data_left = chunking_datasize;
584 DEBUG(D_receive) debug_printf("chunking state %d, %d bytes\n",
585 (int)chunking_state, chunking_data_left);
587 if (chunking_datasize == 0)
588 if (chunking_state == CHUNKING_LAST)
592 (void) synprot_error(L_smtp_protocol_error, 504, NULL,
593 US"zero size for BDAT command");
594 goto repeat_until_rset;
597 receive_getc = bdat_getc;
598 receive_ungetc = bdat_ungetc;
600 dkim_collect_input = dkim_save;
602 break; /* to top of main loop */
609 bdat_flush_data(void)
611 while (chunking_data_left > 0)
612 if (lwr_receive_getc(chunking_data_left--) < 0)
615 receive_getc = lwr_receive_getc;
616 receive_ungetc = lwr_receive_ungetc;
618 if (chunking_state != CHUNKING_LAST)
620 chunking_state = CHUNKING_OFFERED;
621 DEBUG(D_receive) debug_printf("chunking state %d\n", (int)chunking_state);
628 /*************************************************
629 * SMTP version of ungetc() *
630 *************************************************/
632 /* Puts a character back in the input buffer. Only ever
638 Returns: the character
652 chunking_data_left++;
653 return lwr_receive_ungetc(ch);
658 /*************************************************
659 * SMTP version of feof() *
660 *************************************************/
662 /* Tests for a previous EOF
665 Returns: non-zero if the eof flag is set
677 /*************************************************
678 * SMTP version of ferror() *
679 *************************************************/
681 /* Tests for a previous read error, and returns with errno
682 restored to what it was when the error was detected.
685 Returns: non-zero if the error flag is set
691 errno = smtp_had_error;
692 return smtp_had_error;
697 /*************************************************
698 * Test for characters in the SMTP buffer *
699 *************************************************/
701 /* Used at the end of a message
710 return smtp_inptr < smtp_inend;
715 /*************************************************
716 * Write formatted string to SMTP channel *
717 *************************************************/
719 /* This is a separate function so that we don't have to repeat everything for
720 TLS support or debugging. It is global so that the daemon and the
721 authentication functions can use it. It does not return any error indication,
722 because major problems such as dropped connections won't show up till an output
723 flush for non-TLS connections. The smtp_fflush() function is available for
724 checking that: for convenience, TLS output errors are remembered here so that
725 they are also picked up later by smtp_fflush().
729 ... optional arguments
735 smtp_printf(const char *format, ...)
739 va_start(ap, format);
740 smtp_vprintf(format, ap);
744 /* This is split off so that verify.c:respond_printf() can, in effect, call
745 smtp_printf(), bearing in mind that in C a vararg function can't directly
746 call another vararg function, only a function which accepts a va_list. */
749 smtp_vprintf(const char *format, va_list ap)
753 yield = string_vformat(big_buffer, big_buffer_size, format, ap);
757 void *reset_point = store_get(0);
758 uschar *msg_copy, *cr, *end;
759 msg_copy = string_copy(big_buffer);
760 end = msg_copy + Ustrlen(msg_copy);
761 while ((cr = Ustrchr(msg_copy, '\r')) != NULL) /* lose CRs */
762 memmove(cr, cr + 1, (end--) - cr);
763 debug_printf("SMTP>> %s", msg_copy);
764 store_reset(reset_point);
769 log_write(0, LOG_MAIN|LOG_PANIC, "string too large in smtp_printf()");
770 smtp_closedown(US"Unexpected error");
771 exim_exit(EXIT_FAILURE);
774 /* If this is the first output for a (non-batch) RCPT command, see if all RCPTs
775 have had the same. Note: this code is also present in smtp_respond(). It would
776 be tidier to have it only in one place, but when it was added, it was easier to
777 do it that way, so as not to have to mess with the code for the RCPT command,
778 which sometimes uses smtp_printf() and sometimes smtp_respond(). */
780 if (rcpt_in_progress)
782 if (rcpt_smtp_response == NULL)
783 rcpt_smtp_response = string_copy(big_buffer);
784 else if (rcpt_smtp_response_same &&
785 Ustrcmp(rcpt_smtp_response, big_buffer) != 0)
786 rcpt_smtp_response_same = FALSE;
787 rcpt_in_progress = FALSE;
790 /* Now write the string */
793 if (tls_in.active >= 0)
795 if (tls_write(TRUE, big_buffer, Ustrlen(big_buffer)) < 0)
796 smtp_write_error = -1;
801 if (fprintf(smtp_out, "%s", big_buffer) < 0) smtp_write_error = -1;
806 /*************************************************
807 * Flush SMTP out and check for error *
808 *************************************************/
810 /* This function isn't currently used within Exim (it detects errors when it
811 tries to read the next SMTP input), but is available for use in local_scan().
812 For non-TLS connections, it flushes the output and checks for errors. For
813 TLS-connections, it checks for a previously-detected TLS write error.
816 Returns: 0 for no error; -1 after an error
822 if (tls_in.active < 0 && fflush(smtp_out) != 0) smtp_write_error = -1;
823 return smtp_write_error;
828 /*************************************************
829 * SMTP command read timeout *
830 *************************************************/
832 /* Signal handler for timing out incoming SMTP commands. This attempts to
835 Argument: signal number (SIGALRM)
840 command_timeout_handler(int sig)
842 sig = sig; /* Keep picky compilers happy */
843 log_write(L_lost_incoming_connection,
844 LOG_MAIN, "SMTP command timeout on%s connection from %s",
845 (tls_in.active >= 0)? " TLS" : "",
846 host_and_ident(FALSE));
847 if (smtp_batched_input)
848 moan_smtp_batch(NULL, "421 SMTP command timeout"); /* Does not return */
849 smtp_notquit_exit(US"command-timeout", US"421",
850 US"%s: SMTP command timeout - closing connection", smtp_active_hostname);
851 exim_exit(EXIT_FAILURE);
856 /*************************************************
858 *************************************************/
860 /* Signal handler for handling SIGTERM. Again, try to finish tidily.
862 Argument: signal number (SIGTERM)
867 command_sigterm_handler(int sig)
869 sig = sig; /* Keep picky compilers happy */
870 log_write(0, LOG_MAIN, "%s closed after SIGTERM", smtp_get_connection_info());
871 if (smtp_batched_input)
872 moan_smtp_batch(NULL, "421 SIGTERM received"); /* Does not return */
873 smtp_notquit_exit(US"signal-exit", US"421",
874 US"%s: Service not available - closing connection", smtp_active_hostname);
875 exim_exit(EXIT_FAILURE);
882 /*************************************************
883 * Restore socket timeout to previous value *
884 *************************************************/
885 /* If the previous value was successfully retrieved, restore
886 it before returning control to the non-proxy routines
888 Arguments: fd - File descriptor for input
889 get_ok - Successfully retrieved previous values
890 tvtmp - Time struct with previous values
891 vslen - Length of time struct
895 restore_socket_timeout(int fd, int get_ok, struct timeval * tvtmp, socklen_t vslen)
898 (void) setsockopt(fd, SOL_SOCKET, SO_RCVTIMEO, CS tvtmp, vslen);
901 /*************************************************
902 * Check if host is required proxy host *
903 *************************************************/
904 /* The function determines if inbound host will be a regular smtp host
905 or if it is configured that it must use Proxy Protocol. A local
913 check_proxy_protocol_host()
917 if ( sender_host_address
918 && (rc = verify_check_this_host(CUSS &hosts_proxy, NULL, NULL,
919 sender_host_address, NULL)) == OK)
922 debug_printf("Detected proxy protocol configured host\n");
923 proxy_session = TRUE;
925 return proxy_session;
929 /*************************************************
930 * Read data until newline or end of buffer *
931 *************************************************/
932 /* While SMTP is server-speaks-first, TLS is client-speaks-first, so we can't
933 read an entire buffer and assume there will be nothing past a proxy protocol
934 header. Our approach normally is to use stdio, but again that relies upon
935 "STARTTLS\r\n" and a server response before the client starts TLS handshake, or
936 reading _nothing_ before client TLS handshake. So we don't want to use the
937 usual buffering reads which may read enough to block TLS starting.
939 So unfortunately we're down to "read one byte at a time, with a syscall each,
940 and expect a little overhead", for all proxy-opened connections which are v1,
941 just to handle the TLS-on-connect case. Since SSL functions wrap the
942 underlying fd, we can't assume that we can feed them any already-read content.
944 We need to know where to read to, the max capacity, and we'll read until we
945 get a CR and one more character. Let the caller scream if it's CR+!LF.
947 Return the amount read.
951 swallow_until_crlf(int fd, uschar *base, int already, int capacity)
953 uschar *to = base + already;
959 /* For "PROXY UNKNOWN\r\n" we, at time of writing, expect to have read
960 up through the \r; for the _normal_ case, we haven't yet seen the \r. */
961 cr = memchr(base, '\r', already);
964 if ((cr - base) < already - 1)
966 /* \r and presumed \n already within what we have; probably not
967 actually proxy protocol, but abort cleanly. */
970 /* \r is last character read, just need one more. */
976 do { ret = recv(fd, to, 1, 0); } while (ret == -1 && errno == EINTR);
987 // reached end without having room for a final newline, abort
992 /*************************************************
993 * Setup host for proxy protocol *
994 *************************************************/
995 /* The function configures the connection based on a header from the
996 inbound host to use Proxy Protocol. The specification is very exact
997 so exit with an error if do not find the exact required pieces. This
998 includes an incorrect number of spaces separating args.
1001 Returns: Boolean success
1005 setup_proxy_protocol_host()
1017 struct { /* TCP/UDP over IPv4, len = 12 */
1023 struct { /* TCP/UDP over IPv6, len = 36 */
1024 uint8_t src_addr[16];
1025 uint8_t dst_addr[16];
1029 struct { /* AF_UNIX sockets, len = 216 */
1030 uschar src_addr[108];
1031 uschar dst_addr[108];
1037 /* Temp variables used in PPv2 address:port parsing */
1039 char tmpip[INET_ADDRSTRLEN];
1040 struct sockaddr_in tmpaddr;
1041 char tmpip6[INET6_ADDRSTRLEN];
1042 struct sockaddr_in6 tmpaddr6;
1044 /* We can't read "all data until end" because while SMTP is
1045 server-speaks-first, the TLS handshake is client-speaks-first, so for
1046 TLS-on-connect ports the proxy protocol header will usually be immediately
1047 followed by a TLS handshake, and with N TLS libraries, we can't reliably
1048 reinject data for reading by those. So instead we first read "enough to be
1049 safely read within the header, and figure out how much more to read".
1050 For v1 we will later read to the end-of-line, for v2 we will read based upon
1053 The v2 sig is 12 octets, and another 4 gets us the length, so we know how much
1054 data is needed total. For v1, where the line looks like:
1055 PROXY TCPn L3src L3dest SrcPort DestPort \r\n
1057 However, for v1 there's also `PROXY UNKNOWN\r\n` which is only 15 octets.
1058 We seem to support that. So, if we read 14 octets then we can tell if we're
1059 v2 or v1. If we're v1, we can continue reading as normal.
1061 If we're v2, we can't slurp up the entire header. We need the length in the
1062 15th & 16th octets, then to read everything after that.
1064 So to safely handle v1 and v2, with client-sent-first supported correctly,
1065 we have to do a minimum of 3 read calls, not 1. Eww.
1068 #define PROXY_INITIAL_READ 14
1069 #define PROXY_V2_HEADER_SIZE 16
1070 #if PROXY_INITIAL_READ > PROXY_V2_HEADER_SIZE
1071 # error Code bug in sizes of data to read for proxy usage
1076 int fd = fileno(smtp_in);
1077 const char v2sig[12] = "\x0D\x0A\x0D\x0A\x00\x0D\x0A\x51\x55\x49\x54\x0A";
1078 uschar * iptype; /* To display debug info */
1080 struct timeval tvtmp;
1081 socklen_t vslen = sizeof(struct timeval);
1084 /* Save current socket timeout values */
1085 get_ok = getsockopt(fd, SOL_SOCKET, SO_RCVTIMEO, CS &tvtmp, &vslen);
1087 /* Proxy Protocol host must send header within a short time
1088 (default 3 seconds) or it's considered invalid */
1089 tv.tv_sec = PROXY_NEGOTIATION_TIMEOUT_SEC;
1090 tv.tv_usec = PROXY_NEGOTIATION_TIMEOUT_USEC;
1091 if (setsockopt(fd, SOL_SOCKET, SO_RCVTIMEO, CS &tv, sizeof(tv)) < 0)
1096 /* The inbound host was declared to be a Proxy Protocol host, so
1097 don't do a PEEK into the data, actually slurp up enough to be
1098 "safe". Can't take it all because TLS-on-connect clients follow
1099 immediately with TLS handshake. */
1100 ret = recv(fd, &hdr, PROXY_INITIAL_READ, 0);
1102 while (ret == -1 && errno == EINTR);
1107 /* For v2, handle reading the length, and then the rest. */
1108 if ((ret == PROXY_INITIAL_READ) && (memcmp(&hdr.v2, v2sig, sizeof(v2sig)) == 0))
1113 /* First get the length fields. */
1116 retmore = recv(fd, (uschar*)&hdr + ret, PROXY_V2_HEADER_SIZE - PROXY_INITIAL_READ, 0);
1117 } while (retmore == -1 && errno == EINTR);
1122 ver = (hdr.v2.ver_cmd & 0xf0) >> 4;
1124 /* May 2014: haproxy combined the version and command into one byte to
1125 allow two full bytes for the length field in order to proxy SSL
1126 connections. SSL Proxy is not supported in this version of Exim, but
1127 must still separate values here. */
1131 DEBUG(D_receive) debug_printf("Invalid Proxy Protocol version: %d\n", ver);
1135 /* The v2 header will always be 16 bytes per the spec. */
1136 size = 16 + ntohs(hdr.v2.len);
1137 DEBUG(D_receive) debug_printf("Detected PROXYv2 header, size %d (limit %d)\n",
1138 size, (int)sizeof(hdr));
1140 /* We should now have 16 octets (PROXY_V2_HEADER_SIZE), and we know the total
1141 amount that we need. Double-check that the size is not unreasonable, then
1143 if (size > sizeof(hdr))
1145 DEBUG(D_receive) debug_printf("PROXYv2 header size unreasonably large; security attack?\n");
1153 retmore = recv(fd, (uschar*)&hdr + ret, size-ret, 0);
1154 } while (retmore == -1 && errno == EINTR);
1158 DEBUG(D_receive) debug_printf("PROXYv2: have %d/%d required octets\n", ret, size);
1159 } while (ret < size);
1161 } /* end scope for getting rest of data for v2 */
1163 /* At this point: if PROXYv2, we've read the exact size required for all data;
1164 if PROXYv1 then we've read "less than required for any valid line" and should
1167 if (ret >= 16 && memcmp(&hdr.v2, v2sig, 12) == 0)
1169 uint8_t cmd = (hdr.v2.ver_cmd & 0x0f);
1173 case 0x01: /* PROXY command */
1176 case 0x11: /* TCPv4 address type */
1178 tmpaddr.sin_addr.s_addr = hdr.v2.addr.ip4.src_addr;
1179 inet_ntop(AF_INET, &tmpaddr.sin_addr, CS &tmpip, sizeof(tmpip));
1180 if (!string_is_ip_address(US tmpip, NULL))
1182 DEBUG(D_receive) debug_printf("Invalid %s source IP\n", iptype);
1185 proxy_local_address = sender_host_address;
1186 sender_host_address = string_copy(US tmpip);
1187 tmpport = ntohs(hdr.v2.addr.ip4.src_port);
1188 proxy_local_port = sender_host_port;
1189 sender_host_port = tmpport;
1190 /* Save dest ip/port */
1191 tmpaddr.sin_addr.s_addr = hdr.v2.addr.ip4.dst_addr;
1192 inet_ntop(AF_INET, &tmpaddr.sin_addr, CS &tmpip, sizeof(tmpip));
1193 if (!string_is_ip_address(US tmpip, NULL))
1195 DEBUG(D_receive) debug_printf("Invalid %s dest port\n", iptype);
1198 proxy_external_address = string_copy(US tmpip);
1199 tmpport = ntohs(hdr.v2.addr.ip4.dst_port);
1200 proxy_external_port = tmpport;
1202 case 0x21: /* TCPv6 address type */
1204 memmove(tmpaddr6.sin6_addr.s6_addr, hdr.v2.addr.ip6.src_addr, 16);
1205 inet_ntop(AF_INET6, &tmpaddr6.sin6_addr, CS &tmpip6, sizeof(tmpip6));
1206 if (!string_is_ip_address(US tmpip6, NULL))
1208 DEBUG(D_receive) debug_printf("Invalid %s source IP\n", iptype);
1211 proxy_local_address = sender_host_address;
1212 sender_host_address = string_copy(US tmpip6);
1213 tmpport = ntohs(hdr.v2.addr.ip6.src_port);
1214 proxy_local_port = sender_host_port;
1215 sender_host_port = tmpport;
1216 /* Save dest ip/port */
1217 memmove(tmpaddr6.sin6_addr.s6_addr, hdr.v2.addr.ip6.dst_addr, 16);
1218 inet_ntop(AF_INET6, &tmpaddr6.sin6_addr, CS &tmpip6, sizeof(tmpip6));
1219 if (!string_is_ip_address(US tmpip6, NULL))
1221 DEBUG(D_receive) debug_printf("Invalid %s dest port\n", iptype);
1224 proxy_external_address = string_copy(US tmpip6);
1225 tmpport = ntohs(hdr.v2.addr.ip6.dst_port);
1226 proxy_external_port = tmpport;
1230 debug_printf("Unsupported PROXYv2 connection type: 0x%02x\n",
1234 /* Unsupported protocol, keep local connection address */
1236 case 0x00: /* LOCAL command */
1237 /* Keep local connection address for LOCAL */
1242 debug_printf("Unsupported PROXYv2 command: 0x%x\n", cmd);
1246 else if (ret >= 8 && memcmp(hdr.v1.line, "PROXY", 5) == 0)
1250 uschar *sp; /* Utility variables follow */
1255 /* get the rest of the line */
1256 r2 = swallow_until_crlf(fd, (uschar*)&hdr, ret, sizeof(hdr)-ret);
1261 p = string_copy(hdr.v1.line);
1262 end = memchr(p, '\r', ret - 1);
1264 if (!end || (end == (uschar*)&hdr + ret) || end[1] != '\n')
1266 DEBUG(D_receive) debug_printf("Partial or invalid PROXY header\n");
1269 *end = '\0'; /* Terminate the string */
1270 size = end + 2 - p; /* Skip header + CRLF */
1271 DEBUG(D_receive) debug_printf("Detected PROXYv1 header\n");
1272 DEBUG(D_receive) debug_printf("Bytes read not within PROXY header: %d\n", ret - size);
1273 /* Step through the string looking for the required fields. Ensure
1274 strict adherence to required formatting, exit for any error. */
1276 if (!isspace(*(p++)))
1278 DEBUG(D_receive) debug_printf("Missing space after PROXY command\n");
1281 if (!Ustrncmp(p, CCS"TCP4", 4))
1283 else if (!Ustrncmp(p,CCS"TCP6", 4))
1285 else if (!Ustrncmp(p,CCS"UNKNOWN", 7))
1287 iptype = US"Unknown";
1292 DEBUG(D_receive) debug_printf("Invalid TCP type\n");
1296 p += Ustrlen(iptype);
1297 if (!isspace(*(p++)))
1299 DEBUG(D_receive) debug_printf("Missing space after TCP4/6 command\n");
1302 /* Find the end of the arg */
1303 if ((sp = Ustrchr(p, ' ')) == NULL)
1306 debug_printf("Did not find proxied src %s\n", iptype);
1310 if(!string_is_ip_address(p, NULL))
1313 debug_printf("Proxied src arg is not an %s address\n", iptype);
1316 proxy_local_address = sender_host_address;
1317 sender_host_address = p;
1319 if ((sp = Ustrchr(p, ' ')) == NULL)
1322 debug_printf("Did not find proxy dest %s\n", iptype);
1326 if(!string_is_ip_address(p, NULL))
1329 debug_printf("Proxy dest arg is not an %s address\n", iptype);
1332 proxy_external_address = p;
1334 if ((sp = Ustrchr(p, ' ')) == NULL)
1336 DEBUG(D_receive) debug_printf("Did not find proxied src port\n");
1340 tmp_port = strtol(CCS p, &endc, 10);
1341 if (*endc || tmp_port == 0)
1344 debug_printf("Proxied src port '%s' not an integer\n", p);
1347 proxy_local_port = sender_host_port;
1348 sender_host_port = tmp_port;
1350 if ((sp = Ustrchr(p, '\0')) == NULL)
1352 DEBUG(D_receive) debug_printf("Did not find proxy dest port\n");
1355 tmp_port = strtol(CCS p, &endc, 10);
1356 if (*endc || tmp_port == 0)
1359 debug_printf("Proxy dest port '%s' not an integer\n", p);
1362 proxy_external_port = tmp_port;
1363 /* Already checked for /r /n above. Good V1 header received. */
1367 /* Wrong protocol */
1368 DEBUG(D_receive) debug_printf("Invalid proxy protocol version negotiation\n");
1369 (void) swallow_until_crlf(fd, (uschar*)&hdr, ret, sizeof(hdr)-ret);
1375 debug_printf("Valid %s sender from Proxy Protocol header\n", iptype);
1376 yield = proxy_session;
1378 /* Don't flush any potential buffer contents. Any input on proxyfail
1379 should cause a synchronization failure */
1382 restore_socket_timeout(fd, get_ok, &tvtmp, vslen);
1387 sender_host_name = NULL;
1388 (void) host_name_lookup();
1389 host_build_sender_fullhost();
1393 proxy_session_failed = TRUE;
1395 debug_printf("Failure to extract proxied host, only QUIT allowed\n");
1402 /*************************************************
1403 * Read one command line *
1404 *************************************************/
1406 /* Strictly, SMTP commands coming over the net are supposed to end with CRLF.
1407 There are sites that don't do this, and in any case internal SMTP probably
1408 should check only for LF. Consequently, we check here for LF only. The line
1409 ends up with [CR]LF removed from its end. If we get an overlong line, treat as
1410 an unknown command. The command is read into the global smtp_cmd_buffer so that
1411 it is available via $smtp_command.
1413 The character reading routine sets up a timeout for each block actually read
1414 from the input (which may contain more than one command). We set up a special
1415 signal handler that closes down the session on a timeout. Control does not
1416 return when it runs.
1419 check_sync if TRUE, check synchronization rules if global option is TRUE
1420 buffer_lim maximum to buffer in lower layer
1422 Returns: a code identifying the command (enumerated above)
1426 smtp_read_command(BOOL check_sync, unsigned buffer_lim)
1431 BOOL hadnull = FALSE;
1433 os_non_restarting_signal(SIGALRM, command_timeout_handler);
1435 while ((c = (receive_getc)(buffer_lim)) != '\n' && c != EOF)
1437 if (ptr >= SMTP_CMD_BUFFER_SIZE)
1439 os_non_restarting_signal(SIGALRM, sigalrm_handler);
1447 smtp_cmd_buffer[ptr++] = c;
1450 receive_linecount++; /* For BSMTP errors */
1451 os_non_restarting_signal(SIGALRM, sigalrm_handler);
1453 /* If hit end of file, return pseudo EOF command. Whether we have a
1454 part-line already read doesn't matter, since this is an error state. */
1456 if (c == EOF) return EOF_CMD;
1458 /* Remove any CR and white space at the end of the line, and terminate the
1461 while (ptr > 0 && isspace(smtp_cmd_buffer[ptr-1])) ptr--;
1462 smtp_cmd_buffer[ptr] = 0;
1464 DEBUG(D_receive) debug_printf("SMTP<< %s\n", smtp_cmd_buffer);
1466 /* NULLs are not allowed in SMTP commands */
1468 if (hadnull) return BADCHAR_CMD;
1470 /* Scan command list and return identity, having set the data pointer
1471 to the start of the actual data characters. Check for SMTP synchronization
1474 for (p = cmd_list; p < cmd_list_end; p++)
1476 #ifdef SUPPORT_PROXY
1477 /* Only allow QUIT command if Proxy Protocol parsing failed */
1478 if (proxy_session && proxy_session_failed && p->cmd != QUIT_CMD)
1482 && strncmpic(smtp_cmd_buffer, US p->name, p->len) == 0
1483 && ( smtp_cmd_buffer[p->len-1] == ':' /* "mail from:" or "rcpt to:" */
1484 || smtp_cmd_buffer[p->len] == 0
1485 || smtp_cmd_buffer[p->len] == ' '
1488 if (smtp_inptr < smtp_inend && /* Outstanding input */
1489 p->cmd < sync_cmd_limit && /* Command should sync */
1490 check_sync && /* Local flag set */
1491 smtp_enforce_sync && /* Global flag set */
1492 sender_host_address != NULL && /* Not local input */
1493 !sender_host_notsocket) /* Really is a socket */
1496 /* The variables $smtp_command and $smtp_command_argument point into the
1497 unmodified input buffer. A copy of the latter is taken for actual
1498 processing, so that it can be chopped up into separate parts if necessary,
1499 for example, when processing a MAIL command options such as SIZE that can
1500 follow the sender address. */
1502 smtp_cmd_argument = smtp_cmd_buffer + p->len;
1503 while (isspace(*smtp_cmd_argument)) smtp_cmd_argument++;
1504 Ustrcpy(smtp_data_buffer, smtp_cmd_argument);
1505 smtp_cmd_data = smtp_data_buffer;
1507 /* Count non-mail commands from those hosts that are controlled in this
1508 way. The default is all hosts. We don't waste effort checking the list
1509 until we get a non-mail command, but then cache the result to save checking
1510 again. If there's a DEFER while checking the host, assume it's in the list.
1512 Note that one instance of RSET, EHLO/HELO, and STARTTLS is allowed at the
1513 start of each incoming message by fiddling with the value in the table. */
1515 if (!p->is_mail_cmd)
1517 if (count_nonmail == TRUE_UNSET) count_nonmail =
1518 verify_check_host(&smtp_accept_max_nonmail_hosts) != FAIL;
1519 if (count_nonmail && ++nonmail_command_count > smtp_accept_max_nonmail)
1520 return TOO_MANY_NONMAIL_CMD;
1523 /* If there is data for a command that does not expect it, generate the
1526 return (p->has_arg || *smtp_cmd_data == 0)? p->cmd : BADARG_CMD;
1530 #ifdef SUPPORT_PROXY
1531 /* Only allow QUIT command if Proxy Protocol parsing failed */
1532 if (proxy_session && proxy_session_failed)
1533 return PROXY_FAIL_IGNORE_CMD;
1536 /* Enforce synchronization for unknown commands */
1538 if (smtp_inptr < smtp_inend && /* Outstanding input */
1539 check_sync && /* Local flag set */
1540 smtp_enforce_sync && /* Global flag set */
1541 sender_host_address != NULL && /* Not local input */
1542 !sender_host_notsocket) /* Really is a socket */
1550 /*************************************************
1551 * Forced closedown of call *
1552 *************************************************/
1554 /* This function is called from log.c when Exim is dying because of a serious
1555 disaster, and also from some other places. If an incoming non-batched SMTP
1556 channel is open, it swallows the rest of the incoming message if in the DATA
1557 phase, sends the reply string, and gives an error to all subsequent commands
1558 except QUIT. The existence of an SMTP call is detected by the non-NULLness of
1562 message SMTP reply string to send, excluding the code
1568 smtp_closedown(uschar *message)
1570 if (smtp_in == NULL || smtp_batched_input) return;
1571 receive_swallow_smtp();
1572 smtp_printf("421 %s\r\n", message);
1574 for (;;) switch(smtp_read_command(FALSE, GETC_BUFFER_UNLIMITED))
1580 smtp_printf("221 %s closing connection\r\n", smtp_active_hostname);
1585 smtp_printf("250 Reset OK\r\n");
1589 smtp_printf("421 %s\r\n", message);
1597 /*************************************************
1598 * Set up connection info for logging *
1599 *************************************************/
1601 /* This function is called when logging information about an SMTP connection.
1602 It sets up appropriate source information, depending on the type of connection.
1603 If sender_fullhost is NULL, we are at a very early stage of the connection;
1604 just use the IP address.
1607 Returns: a string describing the connection
1611 smtp_get_connection_info(void)
1613 const uschar * hostname = sender_fullhost
1614 ? sender_fullhost : sender_host_address;
1617 return string_sprintf("SMTP connection from %s", hostname);
1619 if (sender_host_unknown || sender_host_notsocket)
1620 return string_sprintf("SMTP connection from %s", sender_ident);
1623 return string_sprintf("SMTP connection from %s (via inetd)", hostname);
1625 if (LOGGING(incoming_interface) && interface_address != NULL)
1626 return string_sprintf("SMTP connection from %s I=[%s]:%d", hostname,
1627 interface_address, interface_port);
1629 return string_sprintf("SMTP connection from %s", hostname);
1635 /* Append TLS-related information to a log line
1638 s String under construction: allocated string to extend, or NULL
1639 sizep Pointer to current allocation size (update on return), or NULL
1640 ptrp Pointer to index for new entries in string (update on return), or NULL
1642 Returns: Allocated string or NULL
1645 s_tlslog(uschar * s, int * sizep, int * ptrp)
1647 int size = sizep ? *sizep : 0;
1648 int ptr = ptrp ? *ptrp : 0;
1650 if (LOGGING(tls_cipher) && tls_in.cipher != NULL)
1651 s = string_append(s, &size, &ptr, 2, US" X=", tls_in.cipher);
1652 if (LOGGING(tls_certificate_verified) && tls_in.cipher != NULL)
1653 s = string_append(s, &size, &ptr, 2, US" CV=",
1654 tls_in.certificate_verified? "yes":"no");
1655 if (LOGGING(tls_peerdn) && tls_in.peerdn != NULL)
1656 s = string_append(s, &size, &ptr, 3, US" DN=\"",
1657 string_printing(tls_in.peerdn), US"\"");
1658 if (LOGGING(tls_sni) && tls_in.sni != NULL)
1659 s = string_append(s, &size, &ptr, 3, US" SNI=\"",
1660 string_printing(tls_in.sni), US"\"");
1665 if (sizep) *sizep = size;
1666 if (ptrp) *ptrp = ptr;
1672 /*************************************************
1673 * Log lack of MAIL if so configured *
1674 *************************************************/
1676 /* This function is called when an SMTP session ends. If the log selector
1677 smtp_no_mail is set, write a log line giving some details of what has happened
1678 in the SMTP session.
1685 smtp_log_no_mail(void)
1690 if (smtp_mailcmd_count > 0 || !LOGGING(smtp_no_mail))
1696 if (sender_host_authenticated != NULL)
1698 s = string_append(s, &size, &ptr, 2, US" A=", sender_host_authenticated);
1699 if (authenticated_id != NULL)
1700 s = string_append(s, &size, &ptr, 2, US":", authenticated_id);
1704 s = s_tlslog(s, &size, &ptr);
1707 sep = (smtp_connection_had[SMTP_HBUFF_SIZE-1] != SCH_NONE)?
1708 US" C=..." : US" C=";
1709 for (i = smtp_ch_index; i < SMTP_HBUFF_SIZE; i++)
1711 if (smtp_connection_had[i] != SCH_NONE)
1713 s = string_append(s, &size, &ptr, 2, sep,
1714 smtp_names[smtp_connection_had[i]]);
1719 for (i = 0; i < smtp_ch_index; i++)
1721 s = string_append(s, &size, &ptr, 2, sep, smtp_names[smtp_connection_had[i]]);
1725 if (s != NULL) s[ptr] = 0; else s = US"";
1726 log_write(0, LOG_MAIN, "no MAIL in SMTP connection from %s D=%s%s",
1727 host_and_ident(FALSE),
1728 readconf_printtime( (int) ((long)time(NULL) - (long)smtp_connection_start)),
1734 /*************************************************
1735 * Check HELO line and set sender_helo_name *
1736 *************************************************/
1738 /* Check the format of a HELO line. The data for HELO/EHLO is supposed to be
1739 the domain name of the sending host, or an ip literal in square brackets. The
1740 argument is placed in sender_helo_name, which is in malloc store, because it
1741 must persist over multiple incoming messages. If helo_accept_junk is set, this
1742 host is permitted to send any old junk (needed for some broken hosts).
1743 Otherwise, helo_allow_chars can be used for rogue characters in general
1744 (typically people want to let in underscores).
1747 s the data portion of the line (already past any white space)
1749 Returns: TRUE or FALSE
1753 check_helo(uschar *s)
1756 uschar *end = s + Ustrlen(s);
1757 BOOL yield = helo_accept_junk;
1759 /* Discard any previous helo name */
1761 if (sender_helo_name != NULL)
1763 store_free(sender_helo_name);
1764 sender_helo_name = NULL;
1767 /* Skip tests if junk is permitted. */
1771 /* Allow the new standard form for IPv6 address literals, namely,
1772 [IPv6:....], and because someone is bound to use it, allow an equivalent
1773 IPv4 form. Allow plain addresses as well. */
1780 if (strncmpic(s, US"[IPv6:", 6) == 0)
1781 yield = (string_is_ip_address(s+6, NULL) == 6);
1782 else if (strncmpic(s, US"[IPv4:", 6) == 0)
1783 yield = (string_is_ip_address(s+6, NULL) == 4);
1785 yield = (string_is_ip_address(s+1, NULL) != 0);
1790 /* Non-literals must be alpha, dot, hyphen, plus any non-valid chars
1791 that have been configured (usually underscore - sigh). */
1798 if (!isalnum(*s) && *s != '.' && *s != '-' &&
1799 Ustrchr(helo_allow_chars, *s) == NULL)
1809 /* Save argument if OK */
1811 if (yield) sender_helo_name = string_copy_malloc(start);
1819 /*************************************************
1820 * Extract SMTP command option *
1821 *************************************************/
1823 /* This function picks the next option setting off the end of smtp_cmd_data. It
1824 is called for MAIL FROM and RCPT TO commands, to pick off the optional ESMTP
1825 things that can appear there.
1828 name point this at the name
1829 value point this at the data string
1831 Returns: TRUE if found an option
1835 extract_option(uschar **name, uschar **value)
1838 uschar *v = smtp_cmd_data + Ustrlen(smtp_cmd_data) - 1;
1839 while (isspace(*v)) v--;
1841 while (v > smtp_cmd_data && *v != '=' && !isspace(*v))
1843 /* Take care to not stop at a space embedded in a quoted local-part */
1845 if (*v == '"') do v--; while (*v != '"' && v > smtp_cmd_data+1);
1852 while(isalpha(n[-1])) n--;
1853 /* RFC says SP, but TAB seen in wild and other major MTAs accept it */
1854 if (!isspace(n[-1])) return FALSE;
1860 if (v == smtp_cmd_data) return FALSE;
1872 /*************************************************
1873 * Reset for new message *
1874 *************************************************/
1876 /* This function is called whenever the SMTP session is reset from
1877 within either of the setup functions.
1879 Argument: the stacking pool storage reset point
1884 smtp_reset(void *reset_point)
1886 recipients_list = NULL;
1887 rcpt_count = rcpt_defer_count = rcpt_fail_count =
1888 raw_recipients_count = recipients_count = recipients_list_max = 0;
1889 cancel_cutthrough_connection("smtp reset");
1890 message_linecount = 0;
1892 acl_added_headers = NULL;
1893 acl_removed_headers = NULL;
1894 queue_only_policy = FALSE;
1895 rcpt_smtp_response = NULL;
1896 rcpt_smtp_response_same = TRUE;
1897 rcpt_in_progress = FALSE;
1898 deliver_freeze = FALSE; /* Can be set by ACL */
1899 freeze_tell = freeze_tell_config; /* Can be set by ACL */
1900 fake_response = OK; /* Can be set by ACL */
1901 #ifdef WITH_CONTENT_SCAN
1902 no_mbox_unspool = FALSE; /* Can be set by ACL */
1904 submission_mode = FALSE; /* Can be set by ACL */
1905 suppress_local_fixups = suppress_local_fixups_default; /* Can be set by ACL */
1906 active_local_from_check = local_from_check; /* Can be set by ACL */
1907 active_local_sender_retain = local_sender_retain; /* Can be set by ACL */
1908 sending_ip_address = NULL;
1909 return_path = sender_address = NULL;
1910 sender_data = NULL; /* Can be set by ACL */
1911 deliver_localpart_orig = NULL;
1912 deliver_domain_orig = NULL;
1913 callout_address = NULL;
1914 submission_name = NULL; /* Can be set by ACL */
1915 raw_sender = NULL; /* After SMTP rewrite, before qualifying */
1916 sender_address_unrewritten = NULL; /* Set only after verify rewrite */
1917 sender_verified_list = NULL; /* No senders verified */
1918 memset(sender_address_cache, 0, sizeof(sender_address_cache));
1919 memset(sender_domain_cache, 0, sizeof(sender_domain_cache));
1921 authenticated_sender = NULL;
1922 #ifdef EXPERIMENTAL_BRIGHTMAIL
1924 bmi_verdicts = NULL;
1926 dnslist_domain = dnslist_matched = NULL;
1927 #ifndef DISABLE_DKIM
1928 dkim_signers = NULL;
1929 dkim_disable_verify = FALSE;
1930 dkim_collect_input = FALSE;
1934 deliver_host = deliver_host_address = NULL; /* Can be set by ACL */
1935 #ifndef DISABLE_PRDR
1936 prdr_requested = FALSE;
1938 #ifdef EXPERIMENTAL_SPF
1939 spf_header_comment = NULL;
1940 spf_received = NULL;
1942 spf_smtp_comment = NULL;
1945 message_smtputf8 = FALSE;
1947 body_linecount = body_zerocount = 0;
1949 sender_rate = sender_rate_limit = sender_rate_period = NULL;
1950 ratelimiters_mail = NULL; /* Updated by ratelimit ACL condition */
1951 /* Note that ratelimiters_conn persists across resets. */
1953 /* Reset message ACL variables */
1957 /* The message body variables use malloc store. They may be set if this is
1958 not the first message in an SMTP session and the previous message caused them
1959 to be referenced in an ACL. */
1963 store_free(message_body);
1964 message_body = NULL;
1967 if (message_body_end)
1969 store_free(message_body_end);
1970 message_body_end = NULL;
1973 /* Warning log messages are also saved in malloc store. They are saved to avoid
1974 repetition in the same message, but it seems right to repeat them for different
1977 while (acl_warn_logged)
1979 string_item *this = acl_warn_logged;
1980 acl_warn_logged = acl_warn_logged->next;
1983 store_reset(reset_point);
1990 /*************************************************
1991 * Initialize for incoming batched SMTP message *
1992 *************************************************/
1994 /* This function is called from smtp_setup_msg() in the case when
1995 smtp_batched_input is true. This happens when -bS is used to pass a whole batch
1996 of messages in one file with SMTP commands between them. All errors must be
1997 reported by sending a message, and only MAIL FROM, RCPT TO, and DATA are
1998 relevant. After an error on a sender, or an invalid recipient, the remainder
1999 of the message is skipped. The value of received_protocol is already set.
2002 Returns: > 0 message successfully started (reached DATA)
2003 = 0 QUIT read or end of file reached
2004 < 0 should not occur
2008 smtp_setup_batch_msg(void)
2011 void *reset_point = store_get(0);
2013 /* Save the line count at the start of each transaction - single commands
2014 like HELO and RSET count as whole transactions. */
2016 bsmtp_transaction_linecount = receive_linecount;
2018 if ((receive_feof)()) return 0; /* Treat EOF as QUIT */
2020 smtp_reset(reset_point); /* Reset for start of message */
2022 /* Deal with SMTP commands. This loop is exited by setting done to a POSITIVE
2023 value. The values are 2 larger than the required yield of the function. */
2028 uschar *recipient = NULL;
2029 int start, end, sender_domain, recipient_domain;
2031 switch(smtp_read_command(FALSE, GETC_BUFFER_UNLIMITED))
2033 /* The HELO/EHLO commands set sender_address_helo if they have
2034 valid data; otherwise they are ignored, except that they do
2035 a reset of the state. */
2040 check_helo(smtp_cmd_data);
2044 smtp_reset(reset_point);
2045 bsmtp_transaction_linecount = receive_linecount;
2049 /* The MAIL FROM command requires an address as an operand. All we
2050 do here is to parse it for syntactic correctness. The form "<>" is
2051 a special case which converts into an empty string. The start/end
2052 pointers in the original are not used further for this address, as
2053 it is the canonical extracted address which is all that is kept. */
2056 smtp_mailcmd_count++; /* Count for no-mail log */
2057 if (sender_address != NULL)
2058 /* The function moan_smtp_batch() does not return. */
2059 moan_smtp_batch(smtp_cmd_buffer, "503 Sender already given");
2061 if (smtp_cmd_data[0] == 0)
2062 /* The function moan_smtp_batch() does not return. */
2063 moan_smtp_batch(smtp_cmd_buffer, "501 MAIL FROM must have an address operand");
2065 /* Reset to start of message */
2067 smtp_reset(reset_point);
2069 /* Apply SMTP rewrite */
2071 raw_sender = ((rewrite_existflags & rewrite_smtp) != 0)?
2072 rewrite_one(smtp_cmd_data, rewrite_smtp|rewrite_smtp_sender, NULL, FALSE,
2073 US"", global_rewrite_rules) : smtp_cmd_data;
2075 /* Extract the address; the TRUE flag allows <> as valid */
2078 parse_extract_address(raw_sender, &errmess, &start, &end, &sender_domain,
2081 if (raw_sender == NULL)
2082 /* The function moan_smtp_batch() does not return. */
2083 moan_smtp_batch(smtp_cmd_buffer, "501 %s", errmess);
2085 sender_address = string_copy(raw_sender);
2087 /* Qualify unqualified sender addresses if permitted to do so. */
2089 if (sender_domain == 0 && sender_address[0] != 0 && sender_address[0] != '@')
2091 if (allow_unqualified_sender)
2093 sender_address = rewrite_address_qualify(sender_address, FALSE);
2094 DEBUG(D_receive) debug_printf("unqualified address %s accepted "
2095 "and rewritten\n", raw_sender);
2097 /* The function moan_smtp_batch() does not return. */
2098 else moan_smtp_batch(smtp_cmd_buffer, "501 sender address must contain "
2104 /* The RCPT TO command requires an address as an operand. All we do
2105 here is to parse it for syntactic correctness. There may be any number
2106 of RCPT TO commands, specifying multiple senders. We build them all into
2107 a data structure that is in argc/argv format. The start/end values
2108 given by parse_extract_address are not used, as we keep only the
2109 extracted address. */
2112 if (sender_address == NULL)
2113 /* The function moan_smtp_batch() does not return. */
2114 moan_smtp_batch(smtp_cmd_buffer, "503 No sender yet given");
2116 if (smtp_cmd_data[0] == 0)
2117 /* The function moan_smtp_batch() does not return. */
2118 moan_smtp_batch(smtp_cmd_buffer, "501 RCPT TO must have an address operand");
2120 /* Check maximum number allowed */
2122 if (recipients_max > 0 && recipients_count + 1 > recipients_max)
2123 /* The function moan_smtp_batch() does not return. */
2124 moan_smtp_batch(smtp_cmd_buffer, "%s too many recipients",
2125 recipients_max_reject? "552": "452");
2127 /* Apply SMTP rewrite, then extract address. Don't allow "<>" as a
2128 recipient address */
2130 recipient = rewrite_existflags & rewrite_smtp
2131 ? rewrite_one(smtp_cmd_data, rewrite_smtp, NULL, FALSE, US"",
2132 global_rewrite_rules)
2135 recipient = parse_extract_address(recipient, &errmess, &start, &end,
2136 &recipient_domain, FALSE);
2139 /* The function moan_smtp_batch() does not return. */
2140 moan_smtp_batch(smtp_cmd_buffer, "501 %s", errmess);
2142 /* If the recipient address is unqualified, qualify it if permitted. Then
2143 add it to the list of recipients. */
2145 if (recipient_domain == 0)
2147 if (allow_unqualified_recipient)
2149 DEBUG(D_receive) debug_printf("unqualified address %s accepted\n",
2151 recipient = rewrite_address_qualify(recipient, TRUE);
2153 /* The function moan_smtp_batch() does not return. */
2154 else moan_smtp_batch(smtp_cmd_buffer, "501 recipient address must contain "
2157 receive_add_recipient(recipient, -1);
2161 /* The DATA command is legal only if it follows successful MAIL FROM
2162 and RCPT TO commands. This function is complete when a valid DATA
2163 command is encountered. */
2166 if (sender_address == NULL || recipients_count <= 0)
2168 /* The function moan_smtp_batch() does not return. */
2169 if (sender_address == NULL)
2170 moan_smtp_batch(smtp_cmd_buffer,
2171 "503 MAIL FROM:<sender> command must precede DATA");
2173 moan_smtp_batch(smtp_cmd_buffer,
2174 "503 RCPT TO:<recipient> must precede DATA");
2178 done = 3; /* DATA successfully achieved */
2179 message_ended = END_NOTENDED; /* Indicate in middle of message */
2184 /* The VRFY, EXPN, HELP, ETRN, and NOOP commands are ignored. */
2191 bsmtp_transaction_linecount = receive_linecount;
2202 /* The function moan_smtp_batch() does not return. */
2203 moan_smtp_batch(smtp_cmd_buffer, "501 Unexpected argument data");
2208 /* The function moan_smtp_batch() does not return. */
2209 moan_smtp_batch(smtp_cmd_buffer, "501 Unexpected NULL in SMTP command");
2214 /* The function moan_smtp_batch() does not return. */
2215 moan_smtp_batch(smtp_cmd_buffer, "500 Command unrecognized");
2220 return done - 2; /* Convert yield values */
2226 /*************************************************
2227 * Start an SMTP session *
2228 *************************************************/
2230 /* This function is called at the start of an SMTP session. Thereafter,
2231 smtp_setup_msg() is called to initiate each separate message. This
2232 function does host-specific testing, and outputs the banner line.
2235 Returns: FALSE if the session can not continue; something has
2236 gone wrong, or the connection to the host is blocked
2240 smtp_start_session(void)
2244 uschar *user_msg, *log_msg;
2248 smtp_connection_start = time(NULL);
2249 for (smtp_ch_index = 0; smtp_ch_index < SMTP_HBUFF_SIZE; smtp_ch_index++)
2250 smtp_connection_had[smtp_ch_index] = SCH_NONE;
2253 /* Default values for certain variables */
2255 helo_seen = esmtp = helo_accept_junk = FALSE;
2256 smtp_mailcmd_count = 0;
2257 count_nonmail = TRUE_UNSET;
2258 synprot_error_count = unknown_command_count = nonmail_command_count = 0;
2259 smtp_delay_mail = smtp_rlm_base;
2260 auth_advertised = FALSE;
2261 pipelining_advertised = FALSE;
2262 pipelining_enable = TRUE;
2263 sync_cmd_limit = NON_SYNC_CMD_NON_PIPELINING;
2264 smtp_exit_function_called = FALSE; /* For avoiding loop in not-quit exit */
2266 /* If receiving by -bs from a trusted user, or testing with -bh, we allow
2267 authentication settings from -oMaa to remain in force. */
2269 if (!host_checking && !sender_host_notsocket) sender_host_authenticated = NULL;
2270 authenticated_by = NULL;
2273 tls_in.cipher = tls_in.peerdn = NULL;
2274 tls_in.ourcert = tls_in.peercert = NULL;
2276 tls_in.ocsp = OCSP_NOT_REQ;
2277 tls_advertised = FALSE;
2279 dsn_advertised = FALSE;
2281 smtputf8_advertised = FALSE;
2284 /* Reset ACL connection variables */
2288 /* Allow for trailing 0 in the command and data buffers. */
2290 if (!(smtp_cmd_buffer = US malloc(2*SMTP_CMD_BUFFER_SIZE + 2)))
2291 log_write(0, LOG_MAIN|LOG_PANIC_DIE,
2292 "malloc() failed for SMTP command buffer");
2294 smtp_cmd_buffer[0] = 0;
2295 smtp_data_buffer = smtp_cmd_buffer + SMTP_CMD_BUFFER_SIZE + 1;
2297 /* For batched input, the protocol setting can be overridden from the
2298 command line by a trusted caller. */
2300 if (smtp_batched_input)
2302 if (!received_protocol) received_protocol = US"local-bsmtp";
2305 /* For non-batched SMTP input, the protocol setting is forced here. It will be
2306 reset later if any of EHLO/AUTH/STARTTLS are received. */
2310 (sender_host_address ? protocols : protocols_local) [pnormal];
2312 /* Set up the buffer for inputting using direct read() calls, and arrange to
2313 call the local functions instead of the standard C ones. */
2315 if (!(smtp_inbuffer = (uschar *)malloc(IN_BUFFER_SIZE)))
2316 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "malloc() failed for SMTP input buffer");
2318 receive_getc = smtp_getc;
2319 receive_get_cache = smtp_get_cache;
2320 receive_ungetc = smtp_ungetc;
2321 receive_feof = smtp_feof;
2322 receive_ferror = smtp_ferror;
2323 receive_smtp_buffered = smtp_buffered;
2324 smtp_inptr = smtp_inend = smtp_inbuffer;
2325 smtp_had_eof = smtp_had_error = 0;
2327 /* Set up the message size limit; this may be host-specific */
2329 thismessage_size_limit = expand_string_integer(message_size_limit, TRUE);
2330 if (expand_string_message != NULL)
2332 if (thismessage_size_limit == -1)
2333 log_write(0, LOG_MAIN|LOG_PANIC, "unable to expand message_size_limit: "
2334 "%s", expand_string_message);
2336 log_write(0, LOG_MAIN|LOG_PANIC, "invalid message_size_limit: "
2337 "%s", expand_string_message);
2338 smtp_closedown(US"Temporary local problem - please try later");
2342 /* When a message is input locally via the -bs or -bS options, sender_host_
2343 unknown is set unless -oMa was used to force an IP address, in which case it
2344 is checked like a real remote connection. When -bs is used from inetd, this
2345 flag is not set, causing the sending host to be checked. The code that deals
2346 with IP source routing (if configured) is never required for -bs or -bS and
2347 the flag sender_host_notsocket is used to suppress it.
2349 If smtp_accept_max and smtp_accept_reserve are set, keep some connections in
2350 reserve for certain hosts and/or networks. */
2352 if (!sender_host_unknown)
2355 BOOL reserved_host = FALSE;
2357 /* Look up IP options (source routing info) on the socket if this is not an
2358 -oMa "host", and if any are found, log them and drop the connection.
2360 Linux (and others now, see below) is different to everyone else, so there
2361 has to be some conditional compilation here. Versions of Linux before 2.1.15
2362 used a structure whose name was "options". Somebody finally realized that
2363 this name was silly, and it got changed to "ip_options". I use the
2364 newer name here, but there is a fudge in the script that sets up os.h
2365 to define a macro in older Linux systems.
2367 Sigh. Linux is a fast-moving target. Another generation of Linux uses
2368 glibc 2, which has chosen ip_opts for the structure name. This is now
2369 really a glibc thing rather than a Linux thing, so the condition name
2370 has been changed to reflect this. It is relevant also to GNU/Hurd.
2372 Mac OS 10.x (Darwin) is like the later glibc versions, but without the
2373 setting of the __GLIBC__ macro, so we can't detect it automatically. There's
2374 a special macro defined in the os.h file.
2376 Some DGUX versions on older hardware appear not to support IP options at
2377 all, so there is now a general macro which can be set to cut out this
2380 How to do this properly in IPv6 is not yet known. */
2382 #if !HAVE_IPV6 && !defined(NO_IP_OPTIONS)
2384 #ifdef GLIBC_IP_OPTIONS
2385 #if (!defined __GLIBC__) || (__GLIBC__ < 2)
2390 #elif defined DARWIN_IP_OPTIONS
2396 if (!host_checking && !sender_host_notsocket)
2399 EXIM_SOCKLEN_T optlen = sizeof(struct ip_options) + MAX_IPOPTLEN;
2400 struct ip_options *ipopt = store_get(optlen);
2402 struct ip_opts ipoptblock;
2403 struct ip_opts *ipopt = &ipoptblock;
2404 EXIM_SOCKLEN_T optlen = sizeof(ipoptblock);
2406 struct ipoption ipoptblock;
2407 struct ipoption *ipopt = &ipoptblock;
2408 EXIM_SOCKLEN_T optlen = sizeof(ipoptblock);
2411 /* Occasional genuine failures of getsockopt() have been seen - for
2412 example, "reset by peer". Therefore, just log and give up on this
2413 call, unless the error is ENOPROTOOPT. This error is given by systems
2414 that have the interfaces but not the mechanism - e.g. GNU/Hurd at the time
2415 of writing. So for that error, carry on - we just can't do an IP options
2418 DEBUG(D_receive) debug_printf("checking for IP options\n");
2420 if (getsockopt(fileno(smtp_out), IPPROTO_IP, IP_OPTIONS, (uschar *)(ipopt),
2423 if (errno != ENOPROTOOPT)
2425 log_write(0, LOG_MAIN, "getsockopt() failed from %s: %s",
2426 host_and_ident(FALSE), strerror(errno));
2427 smtp_printf("451 SMTP service not available\r\n");
2432 /* Deal with any IP options that are set. On the systems I have looked at,
2433 the value of MAX_IPOPTLEN has been 40, meaning that there should never be
2434 more logging data than will fit in big_buffer. Nevertheless, after somebody
2435 questioned this code, I've added in some paranoid checking. */
2437 else if (optlen > 0)
2439 uschar *p = big_buffer;
2440 uschar *pend = big_buffer + big_buffer_size;
2441 uschar *opt, *adptr;
2443 struct in_addr addr;
2446 uschar *optstart = (uschar *)(ipopt->__data);
2448 uschar *optstart = (uschar *)(ipopt->ip_opts);
2450 uschar *optstart = (uschar *)(ipopt->ipopt_list);
2453 DEBUG(D_receive) debug_printf("IP options exist\n");
2455 Ustrcpy(p, "IP options on incoming call:");
2458 for (opt = optstart; opt != NULL &&
2459 opt < (uschar *)(ipopt) + optlen;)
2473 if (!string_format(p, pend-p, " %s [@%s",
2474 (*opt == IPOPT_SSRR)? "SSRR" : "LSRR",
2476 inet_ntoa(*((struct in_addr *)(&(ipopt->faddr))))))
2478 inet_ntoa(ipopt->ip_dst)))
2480 inet_ntoa(ipopt->ipopt_dst)))
2488 optcount = (opt[1] - 3) / sizeof(struct in_addr);
2490 while (optcount-- > 0)
2492 memcpy(&addr, adptr, sizeof(addr));
2493 if (!string_format(p, pend - p - 1, "%s%s",
2494 (optcount == 0)? ":" : "@", inet_ntoa(addr)))
2500 adptr += sizeof(struct in_addr);
2509 if (pend - p < 4 + 3*opt[1]) { opt = NULL; break; }
2512 for (i = 0; i < opt[1]; i++)
2514 sprintf(CS p, "%2.2x ", opt[i]);
2525 log_write(0, LOG_MAIN, "%s", big_buffer);
2527 /* Refuse any call with IP options. This is what tcpwrappers 7.5 does. */
2529 log_write(0, LOG_MAIN|LOG_REJECT,
2530 "connection from %s refused (IP options)", host_and_ident(FALSE));
2532 smtp_printf("554 SMTP service not available\r\n");
2536 /* Length of options = 0 => there are no options */
2538 else DEBUG(D_receive) debug_printf("no IP options found\n");
2540 #endif /* HAVE_IPV6 && !defined(NO_IP_OPTIONS) */
2542 /* Set keep-alive in socket options. The option is on by default. This
2543 setting is an attempt to get rid of some hanging connections that stick in
2544 read() when the remote end (usually a dialup) goes away. */
2546 if (smtp_accept_keepalive && !sender_host_notsocket)
2547 ip_keepalive(fileno(smtp_out), sender_host_address, FALSE);
2549 /* If the current host matches host_lookup, set the name by doing a
2550 reverse lookup. On failure, sender_host_name will be NULL and
2551 host_lookup_failed will be TRUE. This may or may not be serious - optional
2554 if (verify_check_host(&host_lookup) == OK)
2556 (void)host_name_lookup();
2557 host_build_sender_fullhost();
2560 /* Delay this until we have the full name, if it is looked up. */
2562 set_process_info("handling incoming connection from %s",
2563 host_and_ident(FALSE));
2565 /* Expand smtp_receive_timeout, if needed */
2567 if (smtp_receive_timeout_s)
2570 if ( !(exp = expand_string(smtp_receive_timeout_s))
2572 || (smtp_receive_timeout = readconf_readtime(exp, 0, FALSE)) < 0
2574 log_write(0, LOG_MAIN|LOG_PANIC,
2575 "bad value for smtp_receive_timeout: '%s'", exp ? exp : US"");
2578 /* Test for explicit connection rejection */
2580 if (verify_check_host(&host_reject_connection) == OK)
2582 log_write(L_connection_reject, LOG_MAIN|LOG_REJECT, "refused connection "
2583 "from %s (host_reject_connection)", host_and_ident(FALSE));
2584 smtp_printf("554 SMTP service not available\r\n");
2588 /* Test with TCP Wrappers if so configured. There is a problem in that
2589 hosts_ctl() returns 0 (deny) under a number of system failure circumstances,
2590 such as disks dying. In these cases, it is desirable to reject with a 4xx
2591 error instead of a 5xx error. There isn't a "right" way to detect such
2592 problems. The following kludge is used: errno is zeroed before calling
2593 hosts_ctl(). If the result is "reject", a 5xx error is given only if the
2594 value of errno is 0 or ENOENT (which happens if /etc/hosts.{allow,deny} does
2597 #ifdef USE_TCP_WRAPPERS
2599 if (!(tcp_wrappers_name = expand_string(tcp_wrappers_daemon_name)))
2600 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "Expansion of \"%s\" "
2601 "(tcp_wrappers_name) failed: %s", string_printing(tcp_wrappers_name),
2602 expand_string_message);
2604 if (!hosts_ctl(tcp_wrappers_name,
2605 sender_host_name ? CS sender_host_name : STRING_UNKNOWN,
2606 sender_host_address ? CS sender_host_address : STRING_UNKNOWN,
2607 sender_ident ? CS sender_ident : STRING_UNKNOWN))
2609 if (errno == 0 || errno == ENOENT)
2611 HDEBUG(D_receive) debug_printf("tcp wrappers rejection\n");
2612 log_write(L_connection_reject,
2613 LOG_MAIN|LOG_REJECT, "refused connection from %s "
2614 "(tcp wrappers)", host_and_ident(FALSE));
2615 smtp_printf("554 SMTP service not available\r\n");
2619 int save_errno = errno;
2620 HDEBUG(D_receive) debug_printf("tcp wrappers rejected with unexpected "
2621 "errno value %d\n", save_errno);
2622 log_write(L_connection_reject,
2623 LOG_MAIN|LOG_REJECT, "temporarily refused connection from %s "
2624 "(tcp wrappers errno=%d)", host_and_ident(FALSE), save_errno);
2625 smtp_printf("451 Temporary local problem - please try later\r\n");
2631 /* Check for reserved slots. The value of smtp_accept_count has already been
2632 incremented to include this process. */
2634 if (smtp_accept_max > 0 &&
2635 smtp_accept_count > smtp_accept_max - smtp_accept_reserve)
2637 if ((rc = verify_check_host(&smtp_reserve_hosts)) != OK)
2639 log_write(L_connection_reject,
2640 LOG_MAIN, "temporarily refused connection from %s: not in "
2641 "reserve list: connected=%d max=%d reserve=%d%s",
2642 host_and_ident(FALSE), smtp_accept_count - 1, smtp_accept_max,
2643 smtp_accept_reserve, (rc == DEFER)? " (lookup deferred)" : "");
2644 smtp_printf("421 %s: Too many concurrent SMTP connections; "
2645 "please try again later\r\n", smtp_active_hostname);
2648 reserved_host = TRUE;
2651 /* If a load level above which only messages from reserved hosts are
2652 accepted is set, check the load. For incoming calls via the daemon, the
2653 check is done in the superior process if there are no reserved hosts, to
2654 save a fork. In all cases, the load average will already be available
2655 in a global variable at this point. */
2657 if (smtp_load_reserve >= 0 &&
2658 load_average > smtp_load_reserve &&
2660 verify_check_host(&smtp_reserve_hosts) != OK)
2662 log_write(L_connection_reject,
2663 LOG_MAIN, "temporarily refused connection from %s: not in "
2664 "reserve list and load average = %.2f", host_and_ident(FALSE),
2665 (double)load_average/1000.0);
2666 smtp_printf("421 %s: Too much load; please try again later\r\n",
2667 smtp_active_hostname);
2671 /* Determine whether unqualified senders or recipients are permitted
2672 for this host. Unfortunately, we have to do this every time, in order to
2673 set the flags so that they can be inspected when considering qualifying
2674 addresses in the headers. For a site that permits no qualification, this
2675 won't take long, however. */
2677 allow_unqualified_sender =
2678 verify_check_host(&sender_unqualified_hosts) == OK;
2680 allow_unqualified_recipient =
2681 verify_check_host(&recipient_unqualified_hosts) == OK;
2683 /* Determine whether HELO/EHLO is required for this host. The requirement
2684 can be hard or soft. */
2686 helo_required = verify_check_host(&helo_verify_hosts) == OK;
2688 helo_verify = verify_check_host(&helo_try_verify_hosts) == OK;
2690 /* Determine whether this hosts is permitted to send syntactic junk
2691 after a HELO or EHLO command. */
2693 helo_accept_junk = verify_check_host(&helo_accept_junk_hosts) == OK;
2696 /* For batch SMTP input we are now done. */
2698 if (smtp_batched_input) return TRUE;
2700 /* If valid Proxy Protocol source is connecting, set up session.
2701 * Failure will not allow any SMTP function other than QUIT. */
2703 #ifdef SUPPORT_PROXY
2704 proxy_session = FALSE;
2705 proxy_session_failed = FALSE;
2706 if (check_proxy_protocol_host())
2707 setup_proxy_protocol_host();
2710 /* Start up TLS if tls_on_connect is set. This is for supporting the legacy
2711 smtps port for use with older style SSL MTAs. */
2714 if (tls_in.on_connect && tls_server_start(tls_require_ciphers) != OK)
2718 /* Run the connect ACL if it exists */
2721 if (acl_smtp_connect)
2724 if ((rc = acl_check(ACL_WHERE_CONNECT, NULL, acl_smtp_connect, &user_msg,
2727 (void) smtp_handle_acl_fail(ACL_WHERE_CONNECT, rc, user_msg, log_msg);
2732 /* Output the initial message for a two-way SMTP connection. It may contain
2733 newlines, which then cause a multi-line response to be given. */
2735 code = US"220"; /* Default status code */
2736 esc = US""; /* Default extended status code */
2737 esclen = 0; /* Length of esc */
2741 if (!(s = expand_string(smtp_banner)))
2742 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "Expansion of \"%s\" (smtp_banner) "
2743 "failed: %s", smtp_banner, expand_string_message);
2749 smtp_message_code(&code, &codelen, &s, NULL, TRUE);
2753 esclen = codelen - 4;
2757 /* Remove any terminating newlines; might as well remove trailing space too */
2760 while (p > s && isspace(p[-1])) p--;
2763 /* It seems that CC:Mail is braindead, and assumes that the greeting message
2764 is all contained in a single IP packet. The original code wrote out the
2765 greeting using several calls to fprint/fputc, and on busy servers this could
2766 cause it to be split over more than one packet - which caused CC:Mail to fall
2767 over when it got the second part of the greeting after sending its first
2768 command. Sigh. To try to avoid this, build the complete greeting message
2769 first, and output it in one fell swoop. This gives a better chance of it
2770 ending up as a single packet. */
2772 ss = store_get(size);
2776 do /* At least once, in case we have an empty string */
2779 uschar *linebreak = Ustrchr(p, '\n');
2780 ss = string_catn(ss, &size, &ptr, code, 3);
2781 if (linebreak == NULL)
2784 ss = string_catn(ss, &size, &ptr, US" ", 1);
2788 len = linebreak - p;
2789 ss = string_catn(ss, &size, &ptr, US"-", 1);
2791 ss = string_catn(ss, &size, &ptr, esc, esclen);
2792 ss = string_catn(ss, &size, &ptr, p, len);
2793 ss = string_catn(ss, &size, &ptr, US"\r\n", 2);
2795 if (linebreak != NULL) p++;
2799 ss[ptr] = 0; /* string_cat leaves room for this */
2801 /* Before we write the banner, check that there is no input pending, unless
2802 this synchronisation check is disabled. */
2806 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP protocol "
2807 "synchronization error (input sent without waiting for greeting): "
2808 "rejected connection from %s input=\"%s\"", host_and_ident(TRUE),
2809 string_printing(smtp_inptr));
2810 smtp_printf("554 SMTP synchronization error\r\n");
2814 /* Now output the banner */
2816 smtp_printf("%s", ss);
2824 /*************************************************
2825 * Handle SMTP syntax and protocol errors *
2826 *************************************************/
2828 /* Write to the log for SMTP syntax errors in incoming commands, if configured
2829 to do so. Then transmit the error response. The return value depends on the
2830 number of syntax and protocol errors in this SMTP session.
2833 type error type, given as a log flag bit
2834 code response code; <= 0 means don't send a response
2835 data data to reflect in the response (can be NULL)
2836 errmess the error message
2838 Returns: -1 limit of syntax/protocol errors NOT exceeded
2839 +1 limit of syntax/protocol errors IS exceeded
2841 These values fit in with the values of the "done" variable in the main
2842 processing loop in smtp_setup_msg(). */
2845 synprot_error(int type, int code, uschar *data, uschar *errmess)
2849 log_write(type, LOG_MAIN, "SMTP %s error in \"%s\" %s %s",
2850 (type == L_smtp_syntax_error)? "syntax" : "protocol",
2851 string_printing(smtp_cmd_buffer), host_and_ident(TRUE), errmess);
2853 if (++synprot_error_count > smtp_max_synprot_errors)
2856 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
2857 "syntax or protocol errors (last command was \"%s\")",
2858 host_and_ident(FALSE), string_printing(smtp_cmd_buffer));
2863 smtp_printf("%d%c%s%s%s\r\n", code, (yield == 1)? '-' : ' ',
2864 (data == NULL)? US"" : data, (data == NULL)? US"" : US": ", errmess);
2866 smtp_printf("%d Too many syntax or protocol errors\r\n", code);
2875 /*************************************************
2876 * Send SMTP response, possibly multiline *
2877 *************************************************/
2879 /* There are, it seems, broken clients out there that cannot handle multiline
2880 responses. If no_multiline_responses is TRUE (it can be set from an ACL), we
2881 output nothing for non-final calls, and only the first line for anything else.
2884 code SMTP code, may involve extended status codes
2885 codelen length of smtp code; if > 4 there's an ESC
2886 final FALSE if the last line isn't the final line
2887 msg message text, possibly containing newlines
2893 smtp_respond(uschar* code, int codelen, BOOL final, uschar *msg)
2898 if (!final && no_multiline_responses) return;
2903 esclen = codelen - 4;
2906 /* If this is the first output for a (non-batch) RCPT command, see if all RCPTs
2907 have had the same. Note: this code is also present in smtp_printf(). It would
2908 be tidier to have it only in one place, but when it was added, it was easier to
2909 do it that way, so as not to have to mess with the code for the RCPT command,
2910 which sometimes uses smtp_printf() and sometimes smtp_respond(). */
2912 if (rcpt_in_progress)
2914 if (rcpt_smtp_response == NULL)
2915 rcpt_smtp_response = string_copy(msg);
2916 else if (rcpt_smtp_response_same &&
2917 Ustrcmp(rcpt_smtp_response, msg) != 0)
2918 rcpt_smtp_response_same = FALSE;
2919 rcpt_in_progress = FALSE;
2922 /* Not output the message, splitting it up into multiple lines if necessary. */
2926 uschar *nl = Ustrchr(msg, '\n');
2929 smtp_printf("%.3s%c%.*s%s\r\n", code, final? ' ':'-', esclen, esc, msg);
2932 else if (nl[1] == 0 || no_multiline_responses)
2934 smtp_printf("%.3s%c%.*s%.*s\r\n", code, final? ' ':'-', esclen, esc,
2935 (int)(nl - msg), msg);
2940 smtp_printf("%.3s-%.*s%.*s\r\n", code, esclen, esc, (int)(nl - msg), msg);
2942 while (isspace(*msg)) msg++;
2950 /*************************************************
2951 * Parse user SMTP message *
2952 *************************************************/
2954 /* This function allows for user messages overriding the response code details
2955 by providing a suitable response code string at the start of the message
2956 user_msg. Check the message for starting with a response code and optionally an
2957 extended status code. If found, check that the first digit is valid, and if so,
2958 change the code pointer and length to use the replacement. An invalid code
2959 causes a panic log; in this case, if the log messages is the same as the user
2960 message, we must also adjust the value of the log message to show the code that
2961 is actually going to be used (the original one).
2963 This function is global because it is called from receive.c as well as within
2966 Note that the code length returned includes the terminating whitespace
2967 character, which is always included in the regex match.
2970 code SMTP code, may involve extended status codes
2971 codelen length of smtp code; if > 4 there's an ESC
2973 log_msg optional log message, to be adjusted with the new SMTP code
2974 check_valid if true, verify the response code
2980 smtp_message_code(uschar **code, int *codelen, uschar **msg, uschar **log_msg,
2986 if (!msg || !*msg) return;
2988 if ((n = pcre_exec(regex_smtp_code, NULL, CS *msg, Ustrlen(*msg), 0,
2989 PCRE_EOPT, ovector, sizeof(ovector)/sizeof(int))) < 0) return;
2991 if (check_valid && (*msg)[0] != (*code)[0])
2993 log_write(0, LOG_MAIN|LOG_PANIC, "configured error code starts with "
2994 "incorrect digit (expected %c) in \"%s\"", (*code)[0], *msg);
2995 if (log_msg != NULL && *log_msg == *msg)
2996 *log_msg = string_sprintf("%s %s", *code, *log_msg + ovector[1]);
3001 *codelen = ovector[1]; /* Includes final space */
3003 *msg += ovector[1]; /* Chop the code off the message */
3010 /*************************************************
3011 * Handle an ACL failure *
3012 *************************************************/
3014 /* This function is called when acl_check() fails. As well as calls from within
3015 this module, it is called from receive.c for an ACL after DATA. It sorts out
3016 logging the incident, and sets up the error response. A message containing
3017 newlines is turned into a multiline SMTP response, but for logging, only the
3020 There's a table of default permanent failure response codes to use in
3021 globals.c, along with the table of names. VFRY is special. Despite RFC1123 it
3022 defaults disabled in Exim. However, discussion in connection with RFC 821bis
3023 (aka RFC 2821) has concluded that the response should be 252 in the disabled
3024 state, because there are broken clients that try VRFY before RCPT. A 5xx
3025 response should be given only when the address is positively known to be
3026 undeliverable. Sigh. We return 252 if there is no VRFY ACL or it provides
3027 no explicit code, but if there is one we let it know best.
3028 Also, for ETRN, 458 is given on refusal, and for AUTH, 503.
3030 From Exim 4.63, it is possible to override the response code details by
3031 providing a suitable response code string at the start of the message provided
3032 in user_msg. The code's first digit is checked for validity.
3035 where where the ACL was called from
3037 user_msg a message that can be included in an SMTP response
3038 log_msg a message for logging
3040 Returns: 0 in most cases
3041 2 if the failure code was FAIL_DROP, in which case the
3042 SMTP connection should be dropped (this value fits with the
3043 "done" variable in smtp_setup_msg() below)
3047 smtp_handle_acl_fail(int where, int rc, uschar *user_msg, uschar *log_msg)
3049 BOOL drop = rc == FAIL_DROP;
3053 uschar *sender_info = US"";
3055 #ifdef WITH_CONTENT_SCAN
3056 where == ACL_WHERE_MIME ? US"during MIME ACL checks" :
3058 where == ACL_WHERE_PREDATA ? US"DATA" :
3059 where == ACL_WHERE_DATA ? US"after DATA" :
3060 #ifndef DISABLE_PRDR
3061 where == ACL_WHERE_PRDR ? US"after DATA PRDR" :
3064 string_sprintf("%s %s", acl_wherenames[where], smtp_cmd_data) :
3065 string_sprintf("%s in \"connect\" ACL", acl_wherenames[where]);
3067 if (drop) rc = FAIL;
3069 /* Set the default SMTP code, and allow a user message to change it. */
3071 smtp_code = rc == FAIL ? acl_wherecodes[where] : US"451";
3072 smtp_message_code(&smtp_code, &codelen, &user_msg, &log_msg,
3073 where != ACL_WHERE_VRFY);
3075 /* We used to have sender_address here; however, there was a bug that was not
3076 updating sender_address after a rewrite during a verify. When this bug was
3077 fixed, sender_address at this point became the rewritten address. I'm not sure
3078 this is what should be logged, so I've changed to logging the unrewritten
3079 address to retain backward compatibility. */
3081 #ifndef WITH_CONTENT_SCAN
3082 if (where == ACL_WHERE_RCPT || where == ACL_WHERE_DATA)
3084 if (where == ACL_WHERE_RCPT || where == ACL_WHERE_DATA || where == ACL_WHERE_MIME)
3087 sender_info = string_sprintf("F=<%s>%s%s%s%s ",
3088 sender_address_unrewritten ? sender_address_unrewritten : sender_address,
3089 sender_host_authenticated ? US" A=" : US"",
3090 sender_host_authenticated ? sender_host_authenticated : US"",
3091 sender_host_authenticated && authenticated_id ? US":" : US"",
3092 sender_host_authenticated && authenticated_id ? authenticated_id : US""
3096 /* If there's been a sender verification failure with a specific message, and
3097 we have not sent a response about it yet, do so now, as a preliminary line for
3098 failures, but not defers. However, always log it for defer, and log it for fail
3099 unless the sender_verify_fail log selector has been turned off. */
3101 if (sender_verified_failed &&
3102 !testflag(sender_verified_failed, af_sverify_told))
3104 BOOL save_rcpt_in_progress = rcpt_in_progress;
3105 rcpt_in_progress = FALSE; /* So as not to treat these as the error */
3107 setflag(sender_verified_failed, af_sverify_told);
3109 if (rc != FAIL || LOGGING(sender_verify_fail))
3110 log_write(0, LOG_MAIN|LOG_REJECT, "%s sender verify %s for <%s>%s",
3111 host_and_ident(TRUE),
3112 ((sender_verified_failed->special_action & 255) == DEFER)? "defer":"fail",
3113 sender_verified_failed->address,
3114 (sender_verified_failed->message == NULL)? US"" :
3115 string_sprintf(": %s", sender_verified_failed->message));
3117 if (rc == FAIL && sender_verified_failed->user_message)
3118 smtp_respond(smtp_code, codelen, FALSE, string_sprintf(
3119 testflag(sender_verified_failed, af_verify_pmfail)?
3120 "Postmaster verification failed while checking <%s>\n%s\n"
3121 "Several RFCs state that you are required to have a postmaster\n"
3122 "mailbox for each mail domain. This host does not accept mail\n"
3123 "from domains whose servers reject the postmaster address."
3125 testflag(sender_verified_failed, af_verify_nsfail)?
3126 "Callback setup failed while verifying <%s>\n%s\n"
3127 "The initial connection, or a HELO or MAIL FROM:<> command was\n"
3128 "rejected. Refusing MAIL FROM:<> does not help fight spam, disregards\n"
3129 "RFC requirements, and stops you from receiving standard bounce\n"
3130 "messages. This host does not accept mail from domains whose servers\n"
3133 "Verification failed for <%s>\n%s",
3134 sender_verified_failed->address,
3135 sender_verified_failed->user_message));
3137 rcpt_in_progress = save_rcpt_in_progress;
3140 /* Sort out text for logging */
3142 log_msg = log_msg ? string_sprintf(": %s", log_msg) : US"";
3143 if ((lognl = Ustrchr(log_msg, '\n'))) *lognl = 0;
3145 /* Send permanent failure response to the command, but the code used isn't
3146 always a 5xx one - see comments at the start of this function. If the original
3147 rc was FAIL_DROP we drop the connection and yield 2. */
3150 smtp_respond(smtp_code, codelen, TRUE,
3151 user_msg ? user_msg : US"Administrative prohibition");
3153 /* Send temporary failure response to the command. Don't give any details,
3154 unless acl_temp_details is set. This is TRUE for a callout defer, a "defer"
3155 verb, and for a header verify when smtp_return_error_details is set.
3157 This conditional logic is all somewhat of a mess because of the odd
3158 interactions between temp_details and return_error_details. One day it should
3159 be re-implemented in a tidier fashion. */
3162 if (acl_temp_details && user_msg)
3164 if ( smtp_return_error_details
3165 && sender_verified_failed
3166 && sender_verified_failed->message
3168 smtp_respond(smtp_code, codelen, FALSE, sender_verified_failed->message);
3170 smtp_respond(smtp_code, codelen, TRUE, user_msg);
3173 smtp_respond(smtp_code, codelen, TRUE,
3174 US"Temporary local problem - please try later");
3176 /* Log the incident to the logs that are specified by log_reject_target
3177 (default main, reject). This can be empty to suppress logging of rejections. If
3178 the connection is not forcibly to be dropped, return 0. Otherwise, log why it
3179 is closing if required and return 2. */
3181 if (log_reject_target != 0)
3184 uschar * tls = s_tlslog(NULL, NULL, NULL);
3185 if (!tls) tls = US"";
3187 uschar * tls = US"";
3189 log_write(where == ACL_WHERE_CONNECT ? L_connection_reject : 0,
3190 log_reject_target, "%s%s%s %s%srejected %s%s",
3191 LOGGING(dnssec) && sender_host_dnssec ? US" DS" : US"",
3192 host_and_ident(TRUE),
3195 rc == FAIL ? US"" : US"temporarily ",
3199 if (!drop) return 0;
3201 log_write(L_smtp_connection, LOG_MAIN, "%s closed by DROP in ACL",
3202 smtp_get_connection_info());
3204 /* Run the not-quit ACL, but without any custom messages. This should not be a
3205 problem, because we get here only if some other ACL has issued "drop", and
3206 in that case, *its* custom messages will have been used above. */
3208 smtp_notquit_exit(US"acl-drop", NULL, NULL);
3215 /*************************************************
3216 * Handle SMTP exit when QUIT is not given *
3217 *************************************************/
3219 /* This function provides a logging/statistics hook for when an SMTP connection
3220 is dropped on the floor or the other end goes away. It's a global function
3221 because it's called from receive.c as well as this module. As well as running
3222 the NOTQUIT ACL, if there is one, this function also outputs a final SMTP
3223 response, either with a custom message from the ACL, or using a default. There
3224 is one case, however, when no message is output - after "drop". In that case,
3225 the ACL that obeyed "drop" has already supplied the custom message, and NULL is
3226 passed to this function.
3228 In case things go wrong while processing this function, causing an error that
3229 may re-enter this function, there is a recursion check.
3232 reason What $smtp_notquit_reason will be set to in the ACL;
3233 if NULL, the ACL is not run
3234 code The error code to return as part of the response
3235 defaultrespond The default message if there's no user_msg
3241 smtp_notquit_exit(uschar *reason, uschar *code, uschar *defaultrespond, ...)
3244 uschar *user_msg = NULL;
3245 uschar *log_msg = NULL;
3247 /* Check for recursive acll */
3249 if (smtp_exit_function_called)
3251 log_write(0, LOG_PANIC, "smtp_notquit_exit() called more than once (%s)",
3255 smtp_exit_function_called = TRUE;
3257 /* Call the not-QUIT ACL, if there is one, unless no reason is given. */
3259 if (acl_smtp_notquit && reason)
3261 smtp_notquit_reason = reason;
3262 if ((rc = acl_check(ACL_WHERE_NOTQUIT, NULL, acl_smtp_notquit, &user_msg,
3263 &log_msg)) == ERROR)
3264 log_write(0, LOG_MAIN|LOG_PANIC, "ACL for not-QUIT returned ERROR: %s",
3268 /* Write an SMTP response if we are expected to give one. As the default
3269 responses are all internal, they should always fit in the buffer, but code a
3270 warning, just in case. Note that string_vformat() still leaves a complete
3271 string, even if it is incomplete. */
3273 if (code && defaultrespond)
3276 smtp_respond(code, 3, TRUE, user_msg);
3281 va_start(ap, defaultrespond);
3282 if (!string_vformat(buffer, sizeof(buffer), CS defaultrespond, ap))
3283 log_write(0, LOG_MAIN|LOG_PANIC, "string too large in smtp_notquit_exit()");
3284 smtp_printf("%s %s\r\n", code, buffer);
3294 /*************************************************
3295 * Verify HELO argument *
3296 *************************************************/
3298 /* This function is called if helo_verify_hosts or helo_try_verify_hosts is
3299 matched. It is also called from ACL processing if verify = helo is used and
3300 verification was not previously tried (i.e. helo_try_verify_hosts was not
3301 matched). The result of its processing is to set helo_verified and
3302 helo_verify_failed. These variables should both be FALSE for this function to
3305 Note that EHLO/HELO is legitimately allowed to quote an address literal. Allow
3306 for IPv6 ::ffff: literals.
3309 Returns: TRUE if testing was completed;
3310 FALSE on a temporary failure
3314 smtp_verify_helo(void)
3318 HDEBUG(D_receive) debug_printf("verifying EHLO/HELO argument \"%s\"\n",
3321 if (sender_helo_name == NULL)
3323 HDEBUG(D_receive) debug_printf("no EHLO/HELO command was issued\n");
3326 /* Deal with the case of -bs without an IP address */
3328 else if (sender_host_address == NULL)
3330 HDEBUG(D_receive) debug_printf("no client IP address: assume success\n");
3331 helo_verified = TRUE;
3334 /* Deal with the more common case when there is a sending IP address */
3336 else if (sender_helo_name[0] == '[')
3338 helo_verified = Ustrncmp(sender_helo_name+1, sender_host_address,
3339 Ustrlen(sender_host_address)) == 0;
3344 if (strncmpic(sender_host_address, US"::ffff:", 7) == 0)
3345 helo_verified = Ustrncmp(sender_helo_name + 1,
3346 sender_host_address + 7, Ustrlen(sender_host_address) - 7) == 0;
3351 { if (helo_verified) debug_printf("matched host address\n"); }
3354 /* Do a reverse lookup if one hasn't already given a positive or negative
3355 response. If that fails, or the name doesn't match, try checking with a forward
3360 if (sender_host_name == NULL && !host_lookup_failed)
3361 yield = host_name_lookup() != DEFER;
3363 /* If a host name is known, check it and all its aliases. */
3365 if (sender_host_name)
3366 if ((helo_verified = strcmpic(sender_host_name, sender_helo_name) == 0))
3368 sender_helo_dnssec = sender_host_dnssec;
3369 HDEBUG(D_receive) debug_printf("matched host name\n");
3373 uschar **aliases = sender_host_aliases;
3375 if ((helo_verified = strcmpic(*aliases++, sender_helo_name) == 0))
3377 sender_helo_dnssec = sender_host_dnssec;
3381 HDEBUG(D_receive) if (helo_verified)
3382 debug_printf("matched alias %s\n", *(--aliases));
3385 /* Final attempt: try a forward lookup of the helo name */
3394 h.name = sender_helo_name;
3401 HDEBUG(D_receive) debug_printf("getting IP address for %s\n",
3403 rc = host_find_bydns(&h, NULL, HOST_FIND_BY_A,
3404 NULL, NULL, NULL, &d, NULL, NULL);
3405 if (rc == HOST_FOUND || rc == HOST_FOUND_LOCAL)
3406 for (hh = &h; hh; hh = hh->next)
3407 if (Ustrcmp(hh->address, sender_host_address) == 0)
3409 helo_verified = TRUE;
3410 if (h.dnssec == DS_YES) sender_helo_dnssec = TRUE;
3413 debug_printf("IP address for %s matches calling address\n"
3414 "Forward DNS security status: %sverified\n",
3415 sender_helo_name, sender_helo_dnssec ? "" : "un");
3422 if (!helo_verified) helo_verify_failed = TRUE; /* We've tried ... */
3429 /*************************************************
3430 * Send user response message *
3431 *************************************************/
3433 /* This function is passed a default response code and a user message. It calls
3434 smtp_message_code() to check and possibly modify the response code, and then
3435 calls smtp_respond() to transmit the response. I put this into a function
3436 just to avoid a lot of repetition.
3439 code the response code
3440 user_msg the user message
3446 smtp_user_msg(uschar *code, uschar *user_msg)
3449 smtp_message_code(&code, &len, &user_msg, NULL, TRUE);
3450 smtp_respond(code, len, TRUE, user_msg);
3456 smtp_in_auth(auth_instance *au, uschar ** s, uschar ** ss)
3458 const uschar *set_id = NULL;
3461 /* Run the checking code, passing the remainder of the command line as
3462 data. Initials the $auth<n> variables as empty. Initialize $0 empty and set
3463 it as the only set numerical variable. The authenticator may set $auth<n>
3464 and also set other numeric variables. The $auth<n> variables are preferred
3465 nowadays; the numerical variables remain for backwards compatibility.
3467 Afterwards, have a go at expanding the set_id string, even if
3468 authentication failed - for bad passwords it can be useful to log the
3469 userid. On success, require set_id to expand and exist, and put it in
3470 authenticated_id. Save this in permanent store, as the working store gets
3471 reset at HELO, RSET, etc. */
3473 for (i = 0; i < AUTH_VARS; i++) auth_vars[i] = NULL;
3475 expand_nlength[0] = 0; /* $0 contains nothing */
3477 rc = (au->info->servercode)(au, smtp_cmd_data);
3478 if (au->set_id) set_id = expand_string(au->set_id);
3479 expand_nmax = -1; /* Reset numeric variables */
3480 for (i = 0; i < AUTH_VARS; i++) auth_vars[i] = NULL; /* Reset $auth<n> */
3482 /* The value of authenticated_id is stored in the spool file and printed in
3483 log lines. It must not contain binary zeros or newline characters. In
3484 normal use, it never will, but when playing around or testing, this error
3485 can (did) happen. To guard against this, ensure that the id contains only
3486 printing characters. */
3488 if (set_id) set_id = string_printing(set_id);
3490 /* For the non-OK cases, set up additional logging data if set_id
3494 set_id = set_id && *set_id
3495 ? string_sprintf(" (set_id=%s)", set_id) : US"";
3497 /* Switch on the result */
3502 if (!au->set_id || set_id) /* Complete success */
3504 if (set_id) authenticated_id = string_copy_malloc(set_id);
3505 sender_host_authenticated = au->name;
3506 authentication_failed = FALSE;
3507 authenticated_fail_id = NULL; /* Impossible to already be set? */
3510 (sender_host_address ? protocols : protocols_local)
3511 [pextend + pauthed + (tls_in.active >= 0 ? pcrpted:0)];
3512 *s = *ss = US"235 Authentication succeeded";
3513 authenticated_by = au;
3517 /* Authentication succeeded, but we failed to expand the set_id string.
3518 Treat this as a temporary error. */
3520 auth_defer_msg = expand_string_message;
3524 if (set_id) authenticated_fail_id = string_copy_malloc(set_id);
3525 *s = string_sprintf("435 Unable to authenticate at present%s",
3526 auth_defer_user_msg);
3527 *ss = string_sprintf("435 Unable to authenticate at present%s: %s",
3528 set_id, auth_defer_msg);
3532 *s = *ss = US"501 Invalid base64 data";
3536 *s = *ss = US"501 Authentication cancelled";
3540 *s = *ss = US"553 Initial data not expected";
3544 if (set_id) authenticated_fail_id = string_copy_malloc(set_id);
3545 *s = US"535 Incorrect authentication data";
3546 *ss = string_sprintf("535 Incorrect authentication data%s", set_id);
3550 if (set_id) authenticated_fail_id = string_copy_malloc(set_id);
3551 *s = US"435 Internal error";
3552 *ss = string_sprintf("435 Internal error%s: return %d from authentication "
3553 "check", set_id, rc);
3565 qualify_recipient(uschar ** recipient, uschar * smtp_cmd_data, uschar * tag)
3568 if (allow_unqualified_recipient || strcmpic(*recipient, US"postmaster") == 0)
3570 DEBUG(D_receive) debug_printf("unqualified address %s accepted\n",
3572 rd = Ustrlen(recipient) + 1;
3573 *recipient = rewrite_address_qualify(*recipient, TRUE);
3576 smtp_printf("501 %s: recipient address must contain a domain\r\n",
3578 log_write(L_smtp_syntax_error,
3579 LOG_MAIN|LOG_REJECT, "unqualified %s rejected: <%s> %s%s",
3580 tag, *recipient, host_and_ident(TRUE), host_lookup_msg);
3588 smtp_quit_handler(uschar ** user_msgp, uschar ** log_msgp)
3591 incomplete_transaction_log(US"QUIT");
3594 int rc = acl_check(ACL_WHERE_QUIT, NULL, acl_smtp_quit, user_msgp, log_msgp);
3596 log_write(0, LOG_MAIN|LOG_PANIC, "ACL for QUIT returned ERROR: %s",
3600 smtp_respond(US"221", 3, TRUE, *user_msgp);
3602 smtp_printf("221 %s closing connection\r\n", smtp_active_hostname);
3605 tls_close(TRUE, TRUE);
3608 log_write(L_smtp_connection, LOG_MAIN, "%s closed by QUIT",
3609 smtp_get_connection_info());
3614 smtp_rset_handler(void)
3617 incomplete_transaction_log(US"RSET");
3618 smtp_printf("250 Reset OK\r\n");
3619 cmd_list[CMD_LIST_RSET].is_mail_cmd = FALSE;
3624 /*************************************************
3625 * Initialize for SMTP incoming message *
3626 *************************************************/
3628 /* This function conducts the initial dialogue at the start of an incoming SMTP
3629 message, and builds a list of recipients. However, if the incoming message
3630 is part of a batch (-bS option) a separate function is called since it would
3631 be messy having tests splattered about all over this function. This function
3632 therefore handles the case where interaction is occurring. The input and output
3633 files are set up in smtp_in and smtp_out.
3635 The global recipients_list is set to point to a vector of recipient_item
3636 blocks, whose number is given by recipients_count. This is extended by the
3637 receive_add_recipient() function. The global variable sender_address is set to
3638 the sender's address. The yield is +1 if a message has been successfully
3639 started, 0 if a QUIT command was encountered or the connection was refused from
3640 the particular host, or -1 if the connection was lost.
3644 Returns: > 0 message successfully started (reached DATA)
3645 = 0 QUIT read or end of file reached or call refused
3650 smtp_setup_msg(void)
3653 BOOL toomany = FALSE;
3654 BOOL discarded = FALSE;
3655 BOOL last_was_rej_mail = FALSE;
3656 BOOL last_was_rcpt = FALSE;
3657 void *reset_point = store_get(0);
3659 DEBUG(D_receive) debug_printf("smtp_setup_msg entered\n");
3661 /* Reset for start of new message. We allow one RSET not to be counted as a
3662 nonmail command, for those MTAs that insist on sending it between every
3663 message. Ditto for EHLO/HELO and for STARTTLS, to allow for going in and out of
3664 TLS between messages (an Exim client may do this if it has messages queued up
3665 for the host). Note: we do NOT reset AUTH at this point. */
3667 smtp_reset(reset_point);
3668 message_ended = END_NOTSTARTED;
3670 chunking_state = chunking_offered ? CHUNKING_OFFERED : CHUNKING_NOT_OFFERED;
3672 cmd_list[CMD_LIST_RSET].is_mail_cmd = TRUE;
3673 cmd_list[CMD_LIST_HELO].is_mail_cmd = TRUE;
3674 cmd_list[CMD_LIST_EHLO].is_mail_cmd = TRUE;
3676 cmd_list[CMD_LIST_STARTTLS].is_mail_cmd = TRUE;
3677 cmd_list[CMD_LIST_TLS_AUTH].is_mail_cmd = TRUE;
3680 /* Set the local signal handler for SIGTERM - it tries to end off tidily */
3682 os_non_restarting_signal(SIGTERM, command_sigterm_handler);
3684 /* Batched SMTP is handled in a different function. */
3686 if (smtp_batched_input) return smtp_setup_batch_msg();
3688 /* Deal with SMTP commands. This loop is exited by setting done to a POSITIVE
3689 value. The values are 2 larger than the required yield of the function. */
3693 const uschar **argv;
3694 uschar *etrn_command;
3695 uschar *etrn_serialize_key;
3697 uschar *log_msg, *smtp_code;
3698 uschar *user_msg = NULL;
3699 uschar *recipient = NULL;
3700 uschar *hello = NULL;
3702 BOOL was_rej_mail = FALSE;
3703 BOOL was_rcpt = FALSE;
3704 void (*oldsignal)(int);
3706 int start, end, sender_domain, recipient_domain;
3710 uschar *orcpt = NULL;
3714 /* Check once per STARTTLS or SSL-on-connect for a TLS AUTH */
3715 if ( tls_in.active >= 0
3717 && tls_in.certificate_verified
3718 && cmd_list[CMD_LIST_TLS_AUTH].is_mail_cmd
3721 cmd_list[CMD_LIST_TLS_AUTH].is_mail_cmd = FALSE;
3723 && (rc = acl_check(ACL_WHERE_AUTH, NULL, acl_smtp_auth,
3724 &user_msg, &log_msg)) != OK
3727 done = smtp_handle_acl_fail(ACL_WHERE_AUTH, rc, user_msg, log_msg);
3731 for (au = auths; au; au = au->next)
3732 if (strcmpic(US"tls", au->driver_name) == 0)
3734 smtp_cmd_data = NULL;
3736 if (smtp_in_auth(au, &s, &ss) == OK)
3737 { DEBUG(D_auth) debug_printf("tls auth succeeded\n"); }
3739 { DEBUG(D_auth) debug_printf("tls auth not succeeded\n"); }
3746 if (smtp_in) /* Avoid pure-ACKs while in cmd pingpong phase */
3747 (void) setsockopt(fileno(smtp_in), IPPROTO_TCP, TCP_QUICKACK,
3748 US &off, sizeof(off));
3751 switch(smtp_read_command(TRUE, GETC_BUFFER_UNLIMITED))
3753 /* The AUTH command is not permitted to occur inside a transaction, and may
3754 occur successfully only once per connection. Actually, that isn't quite
3755 true. When TLS is started, all previous information about a connection must
3756 be discarded, so a new AUTH is permitted at that time.
3758 AUTH may only be used when it has been advertised. However, it seems that
3759 there are clients that send AUTH when it hasn't been advertised, some of
3760 them even doing this after HELO. And there are MTAs that accept this. Sigh.
3761 So there's a get-out that allows this to happen.
3763 AUTH is initially labelled as a "nonmail command" so that one occurrence
3764 doesn't get counted. We change the label here so that multiple failing
3765 AUTHS will eventually hit the nonmail threshold. */
3769 authentication_failed = TRUE;
3770 cmd_list[CMD_LIST_AUTH].is_mail_cmd = FALSE;
3772 if (!auth_advertised && !allow_auth_unadvertised)
3774 done = synprot_error(L_smtp_protocol_error, 503, NULL,
3775 US"AUTH command used when not advertised");
3778 if (sender_host_authenticated)
3780 done = synprot_error(L_smtp_protocol_error, 503, NULL,
3781 US"already authenticated");
3786 done = synprot_error(L_smtp_protocol_error, 503, NULL,
3787 US"not permitted in mail transaction");
3794 && (rc = acl_check(ACL_WHERE_AUTH, NULL, acl_smtp_auth,
3795 &user_msg, &log_msg)) != OK
3798 done = smtp_handle_acl_fail(ACL_WHERE_AUTH, rc, user_msg, log_msg);
3802 /* Find the name of the requested authentication mechanism. */
3805 while ((c = *smtp_cmd_data) != 0 && !isspace(c))
3807 if (!isalnum(c) && c != '-' && c != '_')
3809 done = synprot_error(L_smtp_syntax_error, 501, NULL,
3810 US"invalid character in authentication mechanism name");
3816 /* If not at the end of the line, we must be at white space. Terminate the
3817 name and move the pointer on to any data that may be present. */
3819 if (*smtp_cmd_data != 0)
3821 *smtp_cmd_data++ = 0;
3822 while (isspace(*smtp_cmd_data)) smtp_cmd_data++;
3825 /* Search for an authentication mechanism which is configured for use
3826 as a server and which has been advertised (unless, sigh, allow_auth_
3827 unadvertised is set). */
3829 for (au = auths; au; au = au->next)
3830 if (strcmpic(s, au->public_name) == 0 && au->server &&
3831 (au->advertised || allow_auth_unadvertised))
3836 c = smtp_in_auth(au, &s, &ss);
3838 smtp_printf("%s\r\n", s);
3840 log_write(0, LOG_MAIN|LOG_REJECT, "%s authenticator failed for %s: %s",
3841 au->name, host_and_ident(FALSE), ss);
3844 done = synprot_error(L_smtp_protocol_error, 504, NULL,
3845 string_sprintf("%s authentication mechanism not supported", s));
3847 break; /* AUTH_CMD */
3849 /* The HELO/EHLO commands are permitted to appear in the middle of a
3850 session as well as at the beginning. They have the effect of a reset in
3851 addition to their other functions. Their absence at the start cannot be
3852 taken to be an error.
3856 If the EHLO command is not acceptable to the SMTP server, 501, 500,
3857 or 502 failure replies MUST be returned as appropriate. The SMTP
3858 server MUST stay in the same state after transmitting these replies
3859 that it was in before the EHLO was received.
3861 Therefore, we do not do the reset until after checking the command for
3862 acceptability. This change was made for Exim release 4.11. Previously
3863 it did the reset first. */
3876 HELO_EHLO: /* Common code for HELO and EHLO */
3877 cmd_list[CMD_LIST_HELO].is_mail_cmd = FALSE;
3878 cmd_list[CMD_LIST_EHLO].is_mail_cmd = FALSE;
3880 /* Reject the HELO if its argument was invalid or non-existent. A
3881 successful check causes the argument to be saved in malloc store. */
3883 if (!check_helo(smtp_cmd_data))
3885 smtp_printf("501 Syntactically invalid %s argument(s)\r\n", hello);
3887 log_write(0, LOG_MAIN|LOG_REJECT, "rejected %s from %s: syntactically "
3888 "invalid argument(s): %s", hello, host_and_ident(FALSE),
3889 (*smtp_cmd_argument == 0)? US"(no argument given)" :
3890 string_printing(smtp_cmd_argument));
3892 if (++synprot_error_count > smtp_max_synprot_errors)
3894 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
3895 "syntax or protocol errors (last command was \"%s\")",
3896 host_and_ident(FALSE), string_printing(smtp_cmd_buffer));
3903 /* If sender_host_unknown is true, we have got here via the -bs interface,
3904 not called from inetd. Otherwise, we are running an IP connection and the
3905 host address will be set. If the helo name is the primary name of this
3906 host and we haven't done a reverse lookup, force one now. If helo_required
3907 is set, ensure that the HELO name matches the actual host. If helo_verify
3908 is set, do the same check, but softly. */
3910 if (!sender_host_unknown)
3912 BOOL old_helo_verified = helo_verified;
3913 uschar *p = smtp_cmd_data;
3915 while (*p != 0 && !isspace(*p)) { *p = tolower(*p); p++; }
3918 /* Force a reverse lookup if HELO quoted something in helo_lookup_domains
3919 because otherwise the log can be confusing. */
3921 if (sender_host_name == NULL &&
3922 (deliver_domain = sender_helo_name, /* set $domain */
3923 match_isinlist(sender_helo_name, CUSS &helo_lookup_domains, 0,
3924 &domainlist_anchor, NULL, MCL_DOMAIN, TRUE, NULL)) == OK)
3925 (void)host_name_lookup();
3927 /* Rebuild the fullhost info to include the HELO name (and the real name
3928 if it was looked up.) */
3930 host_build_sender_fullhost(); /* Rebuild */
3931 set_process_info("handling%s incoming connection from %s",
3932 (tls_in.active >= 0)? " TLS" : "", host_and_ident(FALSE));
3934 /* Verify if configured. This doesn't give much security, but it does
3935 make some people happy to be able to do it. If helo_required is set,
3936 (host matches helo_verify_hosts) failure forces rejection. If helo_verify
3937 is set (host matches helo_try_verify_hosts), it does not. This is perhaps
3938 now obsolescent, since the verification can now be requested selectively
3941 helo_verified = helo_verify_failed = sender_helo_dnssec = FALSE;
3942 if (helo_required || helo_verify)
3944 BOOL tempfail = !smtp_verify_helo();
3949 smtp_printf("%d %s argument does not match calling host\r\n",
3950 tempfail? 451 : 550, hello);
3951 log_write(0, LOG_MAIN|LOG_REJECT, "%srejected \"%s %s\" from %s",
3952 tempfail? "temporarily " : "",
3953 hello, sender_helo_name, host_and_ident(FALSE));
3954 helo_verified = old_helo_verified;
3955 break; /* End of HELO/EHLO processing */
3957 HDEBUG(D_all) debug_printf("%s verification failed but host is in "
3958 "helo_try_verify_hosts\n", hello);
3963 #ifdef EXPERIMENTAL_SPF
3964 /* set up SPF context */
3965 spf_init(sender_helo_name, sender_host_address);
3968 /* Apply an ACL check if one is defined; afterwards, recheck
3969 synchronization in case the client started sending in a delay. */
3972 if ((rc = acl_check(ACL_WHERE_HELO, NULL, acl_smtp_helo,
3973 &user_msg, &log_msg)) != OK)
3975 done = smtp_handle_acl_fail(ACL_WHERE_HELO, rc, user_msg, log_msg);
3976 sender_helo_name = NULL;
3977 host_build_sender_fullhost(); /* Rebuild */
3980 else if (!check_sync()) goto SYNC_FAILURE;
3982 /* Generate an OK reply. The default string includes the ident if present,
3983 and also the IP address if present. Reflecting back the ident is intended
3984 as a deterrent to mail forgers. For maximum efficiency, and also because
3985 some broken systems expect each response to be in a single packet, arrange
3986 that the entire reply is sent in one write(). */
3988 auth_advertised = FALSE;
3989 pipelining_advertised = FALSE;
3991 tls_advertised = FALSE;
3993 dsn_advertised = FALSE;
3995 smtputf8_advertised = FALSE;
3998 smtp_code = US"250 "; /* Default response code plus space*/
3999 if (user_msg == NULL)
4001 s = string_sprintf("%.3s %s Hello %s%s%s",
4003 smtp_active_hostname,
4004 (sender_ident == NULL)? US"" : sender_ident,
4005 (sender_ident == NULL)? US"" : US" at ",
4006 (sender_host_name == NULL)? sender_helo_name : sender_host_name);
4011 if (sender_host_address != NULL)
4013 s = string_catn(s, &size, &ptr, US" [", 2);
4014 s = string_cat (s, &size, &ptr, sender_host_address);
4015 s = string_catn(s, &size, &ptr, US"]", 1);
4019 /* A user-supplied EHLO greeting may not contain more than one line. Note
4020 that the code returned by smtp_message_code() includes the terminating
4021 whitespace character. */
4027 smtp_message_code(&smtp_code, &codelen, &user_msg, NULL, TRUE);
4028 s = string_sprintf("%.*s%s", codelen, smtp_code, user_msg);
4029 if ((ss = strpbrk(CS s, "\r\n")) != NULL)
4031 log_write(0, LOG_MAIN|LOG_PANIC, "EHLO/HELO response must not contain "
4032 "newlines: message truncated: %s", string_printing(s));
4039 s = string_catn(s, &size, &ptr, US"\r\n", 2);
4041 /* If we received EHLO, we must create a multiline response which includes
4042 the functions supported. */
4048 /* I'm not entirely happy with this, as an MTA is supposed to check
4049 that it has enough room to accept a message of maximum size before
4050 it sends this. However, there seems little point in not sending it.
4051 The actual size check happens later at MAIL FROM time. By postponing it
4052 till then, VRFY and EXPN can be used after EHLO when space is short. */
4054 if (thismessage_size_limit > 0)
4056 sprintf(CS big_buffer, "%.3s-SIZE %d\r\n", smtp_code,
4057 thismessage_size_limit);
4058 s = string_cat(s, &size, &ptr, big_buffer);
4062 s = string_catn(s, &size, &ptr, smtp_code, 3);
4063 s = string_catn(s, &size, &ptr, US"-SIZE\r\n", 7);
4066 /* Exim does not do protocol conversion or data conversion. It is 8-bit
4067 clean; if it has an 8-bit character in its hand, it just sends it. It
4068 cannot therefore specify 8BITMIME and remain consistent with the RFCs.
4069 However, some users want this option simply in order to stop MUAs
4070 mangling messages that contain top-bit-set characters. It is therefore
4071 provided as an option. */
4073 if (accept_8bitmime)
4075 s = string_catn(s, &size, &ptr, smtp_code, 3);
4076 s = string_catn(s, &size, &ptr, US"-8BITMIME\r\n", 11);
4079 /* Advertise DSN support if configured to do so. */
4080 if (verify_check_host(&dsn_advertise_hosts) != FAIL)
4082 s = string_catn(s, &size, &ptr, smtp_code, 3);
4083 s = string_catn(s, &size, &ptr, US"-DSN\r\n", 6);
4084 dsn_advertised = TRUE;
4087 /* Advertise ETRN/VRFY/EXPN if there's are ACL checking whether a host is
4088 permitted to issue them; a check is made when any host actually tries. */
4092 s = string_catn(s, &size, &ptr, smtp_code, 3);
4093 s = string_catn(s, &size, &ptr, US"-ETRN\r\n", 7);
4097 s = string_catn(s, &size, &ptr, smtp_code, 3);
4098 s = string_catn(s, &size, &ptr, US"-VRFY\r\n", 7);
4102 s = string_catn(s, &size, &ptr, smtp_code, 3);
4103 s = string_catn(s, &size, &ptr, US"-EXPN\r\n", 7);
4106 /* Exim is quite happy with pipelining, so let the other end know that
4107 it is safe to use it, unless advertising is disabled. */
4109 if (pipelining_enable &&
4110 verify_check_host(&pipelining_advertise_hosts) == OK)
4112 s = string_catn(s, &size, &ptr, smtp_code, 3);
4113 s = string_catn(s, &size, &ptr, US"-PIPELINING\r\n", 13);
4114 sync_cmd_limit = NON_SYNC_CMD_PIPELINING;
4115 pipelining_advertised = TRUE;
4119 /* If any server authentication mechanisms are configured, advertise
4120 them if the current host is in auth_advertise_hosts. The problem with
4121 advertising always is that some clients then require users to
4122 authenticate (and aren't configurable otherwise) even though it may not
4123 be necessary (e.g. if the host is in host_accept_relay).
4125 RFC 2222 states that SASL mechanism names contain only upper case
4126 letters, so output the names in upper case, though we actually recognize
4127 them in either case in the AUTH command. */
4131 && !sender_host_authenticated
4133 && verify_check_host(&auth_advertise_hosts) == OK
4138 for (au = auths; au; au = au->next)
4139 if (au->server && (au->advertise_condition == NULL ||
4140 expand_check_condition(au->advertise_condition, au->name,
4141 US"authenticator")))
4146 s = string_catn(s, &size, &ptr, smtp_code, 3);
4147 s = string_catn(s, &size, &ptr, US"-AUTH", 5);
4149 auth_advertised = TRUE;
4152 s = string_catn(s, &size, &ptr, US" ", 1);
4153 s = string_cat (s, &size, &ptr, au->public_name);
4154 while (++saveptr < ptr) s[saveptr] = toupper(s[saveptr]);
4155 au->advertised = TRUE;
4158 au->advertised = FALSE;
4160 if (!first) s = string_catn(s, &size, &ptr, US"\r\n", 2);
4163 /* RFC 3030 CHUNKING */
4165 if (verify_check_host(&chunking_advertise_hosts) != FAIL)
4167 s = string_catn(s, &size, &ptr, smtp_code, 3);
4168 s = string_catn(s, &size, &ptr, US"-CHUNKING\r\n", 11);
4169 chunking_offered = TRUE;
4170 chunking_state = CHUNKING_OFFERED;
4173 /* Advertise TLS (Transport Level Security) aka SSL (Secure Socket Layer)
4174 if it has been included in the binary, and the host matches
4175 tls_advertise_hosts. We must *not* advertise if we are already in a
4176 secure connection. */
4179 if (tls_in.active < 0 &&
4180 verify_check_host(&tls_advertise_hosts) != FAIL)
4182 s = string_catn(s, &size, &ptr, smtp_code, 3);
4183 s = string_catn(s, &size, &ptr, US"-STARTTLS\r\n", 11);
4184 tls_advertised = TRUE;
4188 #ifndef DISABLE_PRDR
4189 /* Per Recipient Data Response, draft by Eric A. Hall extending RFC */
4192 s = string_catn(s, &size, &ptr, smtp_code, 3);
4193 s = string_catn(s, &size, &ptr, US"-PRDR\r\n", 7);
4198 if ( accept_8bitmime
4199 && verify_check_host(&smtputf8_advertise_hosts) != FAIL)
4201 s = string_catn(s, &size, &ptr, smtp_code, 3);
4202 s = string_catn(s, &size, &ptr, US"-SMTPUTF8\r\n", 11);
4203 smtputf8_advertised = TRUE;
4207 /* Finish off the multiline reply with one that is always available. */
4209 s = string_catn(s, &size, &ptr, smtp_code, 3);
4210 s = string_catn(s, &size, &ptr, US" HELP\r\n", 7);
4213 /* Terminate the string (for debug), write it, and note that HELO/EHLO
4219 if (tls_in.active >= 0) (void)tls_write(TRUE, s, ptr); else
4223 int i = fwrite(s, 1, ptr, smtp_out); i = i; /* compiler quietening */
4228 while ((cr = Ustrchr(s, '\r')) != NULL) /* lose CRs */
4229 memmove(cr, cr + 1, (ptr--) - (cr - s));
4230 debug_printf("SMTP>> %s", s);
4234 /* Reset the protocol and the state, abandoning any previous message. */
4236 (sender_host_address ? protocols : protocols_local)
4238 ? pextend + (sender_host_authenticated ? pauthed : 0)
4240 + (tls_in.active >= 0 ? pcrpted : 0)
4242 smtp_reset(reset_point);
4244 break; /* HELO/EHLO */
4247 /* The MAIL command requires an address as an operand. All we do
4248 here is to parse it for syntactic correctness. The form "<>" is
4249 a special case which converts into an empty string. The start/end
4250 pointers in the original are not used further for this address, as
4251 it is the canonical extracted address which is all that is kept. */
4255 smtp_mailcmd_count++; /* Count for limit and ratelimit */
4256 was_rej_mail = TRUE; /* Reset if accepted */
4257 env_mail_type_t * mail_args; /* Sanity check & validate args */
4259 if (helo_required && !helo_seen)
4261 smtp_printf("503 HELO or EHLO required\r\n");
4262 log_write(0, LOG_MAIN|LOG_REJECT, "rejected MAIL from %s: no "
4263 "HELO/EHLO given", host_and_ident(FALSE));
4267 if (sender_address != NULL)
4269 done = synprot_error(L_smtp_protocol_error, 503, NULL,
4270 US"sender already given");
4274 if (smtp_cmd_data[0] == 0)
4276 done = synprot_error(L_smtp_protocol_error, 501, NULL,
4277 US"MAIL must have an address operand");
4281 /* Check to see if the limit for messages per connection would be
4282 exceeded by accepting further messages. */
4284 if (smtp_accept_max_per_connection > 0 &&
4285 smtp_mailcmd_count > smtp_accept_max_per_connection)
4287 smtp_printf("421 too many messages in this connection\r\n");
4288 log_write(0, LOG_MAIN|LOG_REJECT, "rejected MAIL command %s: too many "
4289 "messages in one connection", host_and_ident(TRUE));
4293 /* Reset for start of message - even if this is going to fail, we
4294 obviously need to throw away any previous data. */
4296 smtp_reset(reset_point);
4298 sender_data = recipient_data = NULL;
4300 /* Loop, checking for ESMTP additions to the MAIL FROM command. */
4304 uschar *name, *value, *end;
4305 unsigned long int size;
4306 BOOL arg_error = FALSE;
4308 if (!extract_option(&name, &value)) break;
4310 for (mail_args = env_mail_type_list;
4311 mail_args->value != ENV_MAIL_OPT_NULL;
4314 if (strcmpic(name, mail_args->name) == 0)
4316 if (mail_args->need_value && strcmpic(value, US"") == 0)
4319 switch(mail_args->value)
4321 /* Handle SIZE= by reading the value. We don't do the check till later,
4322 in order to be able to log the sender address on failure. */
4323 case ENV_MAIL_OPT_SIZE:
4324 if (((size = Ustrtoul(value, &end, 10)), *end == 0))
4326 if ((size == ULONG_MAX && errno == ERANGE) || size > INT_MAX)
4328 message_size = (int)size;
4334 /* If this session was initiated with EHLO and accept_8bitmime is set,
4335 Exim will have indicated that it supports the BODY=8BITMIME option. In
4336 fact, it does not support this according to the RFCs, in that it does not
4337 take any special action for forwarding messages containing 8-bit
4338 characters. That is why accept_8bitmime is not the default setting, but
4339 some sites want the action that is provided. We recognize both "8BITMIME"
4340 and "7BIT" as body types, but take no action. */
4341 case ENV_MAIL_OPT_BODY:
4342 if (accept_8bitmime) {
4343 if (strcmpic(value, US"8BITMIME") == 0)
4345 else if (strcmpic(value, US"7BIT") == 0)
4350 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4351 US"invalid data for BODY");
4354 DEBUG(D_receive) debug_printf("8BITMIME: %d\n", body_8bitmime);
4360 /* Handle the two DSN options, but only if configured to do so (which
4361 will have caused "DSN" to be given in the EHLO response). The code itself
4362 is included only if configured in at build time. */
4364 case ENV_MAIL_OPT_RET:
4367 /* Check if RET has already been set */
4370 synprot_error(L_smtp_syntax_error, 501, NULL,
4371 US"RET can be specified once only");
4374 dsn_ret = strcmpic(value, US"HDRS") == 0
4376 : strcmpic(value, US"FULL") == 0
4379 DEBUG(D_receive) debug_printf("DSN_RET: %d\n", dsn_ret);
4380 /* Check for invalid invalid value, and exit with error */
4383 synprot_error(L_smtp_syntax_error, 501, NULL,
4384 US"Value for RET is invalid");
4389 case ENV_MAIL_OPT_ENVID:
4392 /* Check if the dsn envid has been already set */
4393 if (dsn_envid != NULL)
4395 synprot_error(L_smtp_syntax_error, 501, NULL,
4396 US"ENVID can be specified once only");
4399 dsn_envid = string_copy(value);
4400 DEBUG(D_receive) debug_printf("DSN_ENVID: %s\n", dsn_envid);
4404 /* Handle the AUTH extension. If the value given is not "<>" and either
4405 the ACL says "yes" or there is no ACL but the sending host is
4406 authenticated, we set it up as the authenticated sender. However, if the
4407 authenticator set a condition to be tested, we ignore AUTH on MAIL unless
4408 the condition is met. The value of AUTH is an xtext, which means that +,
4409 = and cntrl chars are coded in hex; however "<>" is unaffected by this
4411 case ENV_MAIL_OPT_AUTH:
4412 if (Ustrcmp(value, "<>") != 0)
4417 if (auth_xtextdecode(value, &authenticated_sender) < 0)
4419 /* Put back terminator overrides for error message */
4422 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4423 US"invalid data for AUTH");
4426 if (acl_smtp_mailauth == NULL)
4428 ignore_msg = US"client not authenticated";
4429 rc = (sender_host_authenticated != NULL)? OK : FAIL;
4433 ignore_msg = US"rejected by ACL";
4434 rc = acl_check(ACL_WHERE_MAILAUTH, NULL, acl_smtp_mailauth,
4435 &user_msg, &log_msg);
4441 if (authenticated_by == NULL ||
4442 authenticated_by->mail_auth_condition == NULL ||
4443 expand_check_condition(authenticated_by->mail_auth_condition,
4444 authenticated_by->name, US"authenticator"))
4445 break; /* Accept the AUTH */
4447 ignore_msg = US"server_mail_auth_condition failed";
4448 if (authenticated_id != NULL)
4449 ignore_msg = string_sprintf("%s: authenticated ID=\"%s\"",
4450 ignore_msg, authenticated_id);
4455 authenticated_sender = NULL;
4456 log_write(0, LOG_MAIN, "ignoring AUTH=%s from %s (%s)",
4457 value, host_and_ident(TRUE), ignore_msg);
4460 /* Should only get DEFER or ERROR here. Put back terminator
4461 overrides for error message */
4466 (void)smtp_handle_acl_fail(ACL_WHERE_MAILAUTH, rc, user_msg,
4473 #ifndef DISABLE_PRDR
4474 case ENV_MAIL_OPT_PRDR:
4476 prdr_requested = TRUE;
4481 case ENV_MAIL_OPT_UTF8:
4482 if (smtputf8_advertised)
4484 int old_pool = store_pool;
4486 DEBUG(D_receive) debug_printf("smtputf8 requested\n");
4487 message_smtputf8 = allow_utf8_domains = TRUE;
4488 store_pool = POOL_PERM;
4489 received_protocol = string_sprintf("utf8%s", received_protocol);
4490 store_pool = old_pool;
4494 /* No valid option. Stick back the terminator characters and break
4495 the loop. Do the name-terminator second as extract_option sets
4496 value==name when it found no equal-sign.
4497 An error for a malformed address will occur. */
4498 case ENV_MAIL_OPT_NULL:
4506 /* Break out of for loop if switch() had bad argument or
4507 when start of the email address is reached */
4508 if (arg_error) break;
4511 /* If we have passed the threshold for rate limiting, apply the current
4512 delay, and update it for next time, provided this is a limited host. */
4514 if (smtp_mailcmd_count > smtp_rlm_threshold &&
4515 verify_check_host(&smtp_ratelimit_hosts) == OK)
4517 DEBUG(D_receive) debug_printf("rate limit MAIL: delay %.3g sec\n",
4518 smtp_delay_mail/1000.0);
4519 millisleep((int)smtp_delay_mail);
4520 smtp_delay_mail *= smtp_rlm_factor;
4521 if (smtp_delay_mail > (double)smtp_rlm_limit)
4522 smtp_delay_mail = (double)smtp_rlm_limit;
4525 /* Now extract the address, first applying any SMTP-time rewriting. The
4526 TRUE flag allows "<>" as a sender address. */
4528 raw_sender = rewrite_existflags & rewrite_smtp
4529 ? rewrite_one(smtp_cmd_data, rewrite_smtp, NULL, FALSE, US"",
4530 global_rewrite_rules)
4534 parse_extract_address(raw_sender, &errmess, &start, &end, &sender_domain,
4539 done = synprot_error(L_smtp_syntax_error, 501, smtp_cmd_data, errmess);
4543 sender_address = raw_sender;
4545 /* If there is a configured size limit for mail, check that this message
4546 doesn't exceed it. The check is postponed to this point so that the sender
4549 if (thismessage_size_limit > 0 && message_size > thismessage_size_limit)
4551 smtp_printf("552 Message size exceeds maximum permitted\r\n");
4552 log_write(L_size_reject,
4553 LOG_MAIN|LOG_REJECT, "rejected MAIL FROM:<%s> %s: "
4554 "message too big: size%s=%d max=%d",
4556 host_and_ident(TRUE),
4557 (message_size == INT_MAX)? ">" : "",
4559 thismessage_size_limit);
4560 sender_address = NULL;
4564 /* Check there is enough space on the disk unless configured not to.
4565 When smtp_check_spool_space is set, the check is for thismessage_size_limit
4566 plus the current message - i.e. we accept the message only if it won't
4567 reduce the space below the threshold. Add 5000 to the size to allow for
4568 overheads such as the Received: line and storing of recipients, etc.
4569 By putting the check here, even when SIZE is not given, it allow VRFY
4570 and EXPN etc. to be used when space is short. */
4572 if (!receive_check_fs(
4573 (smtp_check_spool_space && message_size >= 0)?
4574 message_size + 5000 : 0))
4576 smtp_printf("452 Space shortage, please try later\r\n");
4577 sender_address = NULL;
4581 /* If sender_address is unqualified, reject it, unless this is a locally
4582 generated message, or the sending host or net is permitted to send
4583 unqualified addresses - typically local machines behaving as MUAs -
4584 in which case just qualify the address. The flag is set above at the start
4585 of the SMTP connection. */
4587 if (sender_domain == 0 && sender_address[0] != 0)
4589 if (allow_unqualified_sender)
4591 sender_domain = Ustrlen(sender_address) + 1;
4592 sender_address = rewrite_address_qualify(sender_address, FALSE);
4593 DEBUG(D_receive) debug_printf("unqualified address %s accepted\n",
4598 smtp_printf("501 %s: sender address must contain a domain\r\n",
4600 log_write(L_smtp_syntax_error,
4601 LOG_MAIN|LOG_REJECT,
4602 "unqualified sender rejected: <%s> %s%s",
4604 host_and_ident(TRUE),
4606 sender_address = NULL;
4611 /* Apply an ACL check if one is defined, before responding. Afterwards,
4612 when pipelining is not advertised, do another sync check in case the ACL
4613 delayed and the client started sending in the meantime. */
4617 rc = acl_check(ACL_WHERE_MAIL, NULL, acl_smtp_mail, &user_msg, &log_msg);
4618 if (rc == OK && !pipelining_advertised && !check_sync())
4624 if (rc == OK || rc == DISCARD)
4627 smtp_printf("%s%s%s", US"250 OK",
4628 #ifndef DISABLE_PRDR
4629 prdr_requested ? US", PRDR Requested" : US"",
4636 #ifndef DISABLE_PRDR
4638 user_msg = string_sprintf("%s%s", user_msg, US", PRDR Requested");
4640 smtp_user_msg(US"250", user_msg);
4642 smtp_delay_rcpt = smtp_rlr_base;
4643 recipients_discarded = (rc == DISCARD);
4644 was_rej_mail = FALSE;
4648 done = smtp_handle_acl_fail(ACL_WHERE_MAIL, rc, user_msg, log_msg);
4649 sender_address = NULL;
4654 /* The RCPT command requires an address as an operand. There may be any
4655 number of RCPT commands, specifying multiple recipients. We build them all
4656 into a data structure. The start/end values given by parse_extract_address
4657 are not used, as we keep only the extracted address. */
4662 was_rcpt = rcpt_in_progress = TRUE;
4664 /* There must be a sender address; if the sender was rejected and
4665 pipelining was advertised, we assume the client was pipelining, and do not
4666 count this as a protocol error. Reset was_rej_mail so that further RCPTs
4667 get the same treatment. */
4669 if (sender_address == NULL)
4671 if (pipelining_advertised && last_was_rej_mail)
4673 smtp_printf("503 sender not yet given\r\n");
4674 was_rej_mail = TRUE;
4678 done = synprot_error(L_smtp_protocol_error, 503, NULL,
4679 US"sender not yet given");
4680 was_rcpt = FALSE; /* Not a valid RCPT */
4686 /* Check for an operand */
4688 if (smtp_cmd_data[0] == 0)
4690 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4691 US"RCPT must have an address operand");
4696 /* Set the DSN flags orcpt and dsn_flags from the session*/
4702 uschar *name, *value;
4704 if (!extract_option(&name, &value))
4707 if (dsn_advertised && strcmpic(name, US"ORCPT") == 0)
4709 /* Check whether orcpt has been already set */
4712 synprot_error(L_smtp_syntax_error, 501, NULL,
4713 US"ORCPT can be specified once only");
4716 orcpt = string_copy(value);
4717 DEBUG(D_receive) debug_printf("DSN orcpt: %s\n", orcpt);
4720 else if (dsn_advertised && strcmpic(name, US"NOTIFY") == 0)
4722 /* Check if the notify flags have been already set */
4725 synprot_error(L_smtp_syntax_error, 501, NULL,
4726 US"NOTIFY can be specified once only");
4729 if (strcmpic(value, US"NEVER") == 0)
4730 flags |= rf_notify_never;
4737 while (*pp != 0 && *pp != ',') pp++;
4738 if (*pp == ',') *pp++ = 0;
4739 if (strcmpic(p, US"SUCCESS") == 0)
4741 DEBUG(D_receive) debug_printf("DSN: Setting notify success\n");
4742 flags |= rf_notify_success;
4744 else if (strcmpic(p, US"FAILURE") == 0)
4746 DEBUG(D_receive) debug_printf("DSN: Setting notify failure\n");
4747 flags |= rf_notify_failure;
4749 else if (strcmpic(p, US"DELAY") == 0)
4751 DEBUG(D_receive) debug_printf("DSN: Setting notify delay\n");
4752 flags |= rf_notify_delay;
4756 /* Catch any strange values */
4757 synprot_error(L_smtp_syntax_error, 501, NULL,
4758 US"Invalid value for NOTIFY parameter");
4763 DEBUG(D_receive) debug_printf("DSN Flags: %x\n", flags);
4767 /* Unknown option. Stick back the terminator characters and break
4768 the loop. An error for a malformed address will occur. */
4772 DEBUG(D_receive) debug_printf("Invalid RCPT option: %s : %s\n", name, value);
4779 /* Apply SMTP rewriting then extract the working address. Don't allow "<>"
4780 as a recipient address */
4782 recipient = rewrite_existflags & rewrite_smtp
4783 ? rewrite_one(smtp_cmd_data, rewrite_smtp, NULL, FALSE, US"",
4784 global_rewrite_rules)
4787 if (!(recipient = parse_extract_address(recipient, &errmess, &start, &end,
4788 &recipient_domain, FALSE)))
4790 done = synprot_error(L_smtp_syntax_error, 501, smtp_cmd_data, errmess);
4795 /* If the recipient address is unqualified, reject it, unless this is a
4796 locally generated message. However, unqualified addresses are permitted
4797 from a configured list of hosts and nets - typically when behaving as
4798 MUAs rather than MTAs. Sad that SMTP is used for both types of traffic,
4799 really. The flag is set at the start of the SMTP connection.
4801 RFC 1123 talks about supporting "the reserved mailbox postmaster"; I always
4802 assumed this meant "reserved local part", but the revision of RFC 821 and
4803 friends now makes it absolutely clear that it means *mailbox*. Consequently
4804 we must always qualify this address, regardless. */
4806 if (!recipient_domain)
4807 if (!(recipient_domain = qualify_recipient(&recipient, smtp_cmd_data,
4814 /* Check maximum allowed */
4816 if (rcpt_count > recipients_max && recipients_max > 0)
4818 if (recipients_max_reject)
4821 smtp_printf("552 too many recipients\r\n");
4823 log_write(0, LOG_MAIN|LOG_REJECT, "too many recipients: message "
4824 "rejected: sender=<%s> %s", sender_address, host_and_ident(TRUE));
4829 smtp_printf("452 too many recipients\r\n");
4831 log_write(0, LOG_MAIN|LOG_REJECT, "too many recipients: excess "
4832 "temporarily rejected: sender=<%s> %s", sender_address,
4833 host_and_ident(TRUE));
4840 /* If we have passed the threshold for rate limiting, apply the current
4841 delay, and update it for next time, provided this is a limited host. */
4843 if (rcpt_count > smtp_rlr_threshold &&
4844 verify_check_host(&smtp_ratelimit_hosts) == OK)
4846 DEBUG(D_receive) debug_printf("rate limit RCPT: delay %.3g sec\n",
4847 smtp_delay_rcpt/1000.0);
4848 millisleep((int)smtp_delay_rcpt);
4849 smtp_delay_rcpt *= smtp_rlr_factor;
4850 if (smtp_delay_rcpt > (double)smtp_rlr_limit)
4851 smtp_delay_rcpt = (double)smtp_rlr_limit;
4854 /* If the MAIL ACL discarded all the recipients, we bypass ACL checking
4855 for them. Otherwise, check the access control list for this recipient. As
4856 there may be a delay in this, re-check for a synchronization error
4857 afterwards, unless pipelining was advertised. */
4859 if (recipients_discarded)
4862 if ( (rc = acl_check(ACL_WHERE_RCPT, recipient, acl_smtp_rcpt, &user_msg,
4864 && !pipelining_advertised && !check_sync())
4867 /* The ACL was happy */
4872 smtp_user_msg(US"250", user_msg);
4874 smtp_printf("250 Accepted\r\n");
4875 receive_add_recipient(recipient, -1);
4877 /* Set the dsn flags in the recipients_list */
4878 recipients_list[recipients_count-1].orcpt = orcpt;
4879 recipients_list[recipients_count-1].dsn_flags = flags;
4881 DEBUG(D_receive) debug_printf("DSN: orcpt: %s flags: %d\n",
4882 recipients_list[recipients_count-1].orcpt,
4883 recipients_list[recipients_count-1].dsn_flags);
4886 /* The recipient was discarded */
4888 else if (rc == DISCARD)
4891 smtp_user_msg(US"250", user_msg);
4893 smtp_printf("250 Accepted\r\n");
4896 log_write(0, LOG_MAIN|LOG_REJECT, "%s F=<%s> RCPT %s: "
4897 "discarded by %s ACL%s%s", host_and_ident(TRUE),
4898 sender_address_unrewritten? sender_address_unrewritten : sender_address,
4899 smtp_cmd_argument, recipients_discarded? "MAIL" : "RCPT",
4900 log_msg ? US": " : US"", log_msg ? log_msg : US"");
4903 /* Either the ACL failed the address, or it was deferred. */
4907 if (rc == FAIL) rcpt_fail_count++; else rcpt_defer_count++;
4908 done = smtp_handle_acl_fail(ACL_WHERE_RCPT, rc, user_msg, log_msg);
4913 /* The DATA command is legal only if it follows successful MAIL FROM
4914 and RCPT TO commands. However, if pipelining is advertised, a bad DATA is
4915 not counted as a protocol error if it follows RCPT (which must have been
4916 rejected if there are no recipients.) This function is complete when a
4917 valid DATA command is encountered.
4919 Note concerning the code used: RFC 2821 says this:
4921 - If there was no MAIL, or no RCPT, command, or all such commands
4922 were rejected, the server MAY return a "command out of sequence"
4923 (503) or "no valid recipients" (554) reply in response to the
4926 The example in the pipelining RFC 2920 uses 554, but I use 503 here
4927 because it is the same whether pipelining is in use or not.
4929 If all the RCPT commands that precede DATA provoked the same error message
4930 (often indicating some kind of system error), it is helpful to include it
4931 with the DATA rejection (an idea suggested by Tony Finch). */
4938 if (chunking_state != CHUNKING_OFFERED)
4940 done = synprot_error(L_smtp_protocol_error, 503, NULL,
4941 US"BDAT command used when CHUNKING not advertised");
4945 /* grab size, endmarker */
4947 if (sscanf(CS smtp_cmd_data, "%u %n", &chunking_datasize, &n) < 1)
4949 done = synprot_error(L_smtp_protocol_error, 501, NULL,
4950 US"missing size for BDAT command");
4953 chunking_state = strcmpic(smtp_cmd_data+n, US"LAST") == 0
4954 ? CHUNKING_LAST : CHUNKING_ACTIVE;
4955 chunking_data_left = chunking_datasize;
4956 DEBUG(D_receive) debug_printf("chunking state %d, %d bytes\n",
4957 (int)chunking_state, chunking_data_left);
4959 lwr_receive_getc = receive_getc;
4960 lwr_receive_ungetc = receive_ungetc;
4961 receive_getc = bdat_getc;
4962 receive_ungetc = bdat_ungetc;
4970 DATA_BDAT: /* Common code for DATA and BDAT */
4971 if (!discarded && recipients_count <= 0)
4973 if (rcpt_smtp_response_same && rcpt_smtp_response != NULL)
4975 uschar *code = US"503";
4976 int len = Ustrlen(rcpt_smtp_response);
4977 smtp_respond(code, 3, FALSE, US"All RCPT commands were rejected with "
4979 /* Responses from smtp_printf() will have \r\n on the end */
4980 if (len > 2 && rcpt_smtp_response[len-2] == '\r')
4981 rcpt_smtp_response[len-2] = 0;
4982 smtp_respond(code, 3, FALSE, rcpt_smtp_response);
4984 if (pipelining_advertised && last_was_rcpt)
4985 smtp_printf("503 Valid RCPT command must precede %s\r\n",
4986 smtp_names[smtp_connection_had[smtp_ch_index-1]]);
4988 done = synprot_error(L_smtp_protocol_error, 503, NULL,
4989 smtp_connection_had[smtp_ch_index-1] == SCH_DATA
4990 ? US"valid RCPT command must precede DATA"
4991 : US"valid RCPT command must precede BDAT");
4993 if (chunking_state > CHUNKING_OFFERED)
4998 if (toomany && recipients_max_reject)
5000 sender_address = NULL; /* This will allow a new MAIL without RSET */
5001 sender_address_unrewritten = NULL;
5002 smtp_printf("554 Too many recipients\r\n");
5006 if (chunking_state > CHUNKING_OFFERED)
5007 rc = OK; /* No predata ACL or go-ahead output for BDAT */
5010 /* If there is an ACL, re-check the synchronization afterwards, since the
5011 ACL may have delayed. To handle cutthrough delivery enforce a dummy call
5012 to get the DATA command sent. */
5014 if (acl_smtp_predata == NULL && cutthrough.fd < 0)
5018 uschar * acl = acl_smtp_predata ? acl_smtp_predata : US"accept";
5019 enable_dollar_recipients = TRUE;
5020 rc = acl_check(ACL_WHERE_PREDATA, NULL, acl, &user_msg,
5022 enable_dollar_recipients = FALSE;
5023 if (rc == OK && !check_sync())
5027 { /* Either the ACL failed the address, or it was deferred. */
5028 done = smtp_handle_acl_fail(ACL_WHERE_PREDATA, rc, user_msg, log_msg);
5034 smtp_user_msg(US"354", user_msg);
5037 "354 Enter message, ending with \".\" on a line by itself\r\n");
5041 if (smtp_in) /* all ACKs needed to ramp window up for bulk data */
5042 (void) setsockopt(fileno(smtp_in), IPPROTO_TCP, TCP_QUICKACK,
5043 US &on, sizeof(on));
5046 message_ended = END_NOTENDED; /* Indicate in middle of data */
5057 if (!(address = parse_extract_address(smtp_cmd_data, &errmess,
5058 &start, &end, &recipient_domain, FALSE)))
5060 smtp_printf("501 %s\r\n", errmess);
5064 if (!recipient_domain)
5065 if (!(recipient_domain = qualify_recipient(&address, smtp_cmd_data,
5069 if ((rc = acl_check(ACL_WHERE_VRFY, address, acl_smtp_vrfy,
5070 &user_msg, &log_msg)) != OK)
5071 done = smtp_handle_acl_fail(ACL_WHERE_VRFY, rc, user_msg, log_msg);
5075 address_item * addr = deliver_make_addr(address, FALSE);
5077 switch(verify_address(addr, NULL, vopt_is_recipient | vopt_qualify, -1,
5078 -1, -1, NULL, NULL, NULL))
5081 s = string_sprintf("250 <%s> is deliverable", address);
5085 s = (addr->user_message != NULL)?
5086 string_sprintf("451 <%s> %s", address, addr->user_message) :
5087 string_sprintf("451 Cannot resolve <%s> at this time", address);
5091 s = (addr->user_message != NULL)?
5092 string_sprintf("550 <%s> %s", address, addr->user_message) :
5093 string_sprintf("550 <%s> is not deliverable", address);
5094 log_write(0, LOG_MAIN, "VRFY failed for %s %s",
5095 smtp_cmd_argument, host_and_ident(TRUE));
5099 smtp_printf("%s\r\n", s);
5107 rc = acl_check(ACL_WHERE_EXPN, NULL, acl_smtp_expn, &user_msg, &log_msg);
5109 done = smtp_handle_acl_fail(ACL_WHERE_EXPN, rc, user_msg, log_msg);
5112 BOOL save_log_testing_mode = log_testing_mode;
5113 address_test_mode = log_testing_mode = TRUE;
5114 (void) verify_address(deliver_make_addr(smtp_cmd_data, FALSE),
5115 smtp_out, vopt_is_recipient | vopt_qualify | vopt_expn, -1, -1, -1,
5117 address_test_mode = FALSE;
5118 log_testing_mode = save_log_testing_mode; /* true for -bh */
5127 if (!tls_advertised)
5129 done = synprot_error(L_smtp_protocol_error, 503, NULL,
5130 US"STARTTLS command used when not advertised");
5134 /* Apply an ACL check if one is defined */
5136 if ( acl_smtp_starttls
5137 && (rc = acl_check(ACL_WHERE_STARTTLS, NULL, acl_smtp_starttls,
5138 &user_msg, &log_msg)) != OK
5141 done = smtp_handle_acl_fail(ACL_WHERE_STARTTLS, rc, user_msg, log_msg);
5145 /* RFC 2487 is not clear on when this command may be sent, though it
5146 does state that all information previously obtained from the client
5147 must be discarded if a TLS session is started. It seems reasonable to
5148 do an implied RSET when STARTTLS is received. */
5150 incomplete_transaction_log(US"STARTTLS");
5151 smtp_reset(reset_point);
5153 cmd_list[CMD_LIST_STARTTLS].is_mail_cmd = FALSE;
5155 /* There's an attack where more data is read in past the STARTTLS command
5156 before TLS is negotiated, then assumed to be part of the secure session
5157 when used afterwards; we use segregated input buffers, so are not
5158 vulnerable, but we want to note when it happens and, for sheer paranoia,
5159 ensure that the buffer is "wiped".
5160 Pipelining sync checks will normally have protected us too, unless disabled
5161 by configuration. */
5163 if (receive_smtp_buffered())
5166 debug_printf("Non-empty input buffer after STARTTLS; naive attack?\n");
5167 if (tls_in.active < 0)
5168 smtp_inend = smtp_inptr = smtp_inbuffer;
5169 /* and if TLS is already active, tls_server_start() should fail */
5172 /* There is nothing we value in the input buffer and if TLS is successfully
5173 negotiated, we won't use this buffer again; if TLS fails, we'll just read
5174 fresh content into it. The buffer contains arbitrary content from an
5175 untrusted remote source; eg: NOOP <shellcode>\r\nSTARTTLS\r\n
5176 It seems safest to just wipe away the content rather than leave it as a
5177 target to jump to. */
5179 memset(smtp_inbuffer, 0, IN_BUFFER_SIZE);
5181 /* Attempt to start up a TLS session, and if successful, discard all
5182 knowledge that was obtained previously. At least, that's what the RFC says,
5183 and that's what happens by default. However, in order to work round YAEB,
5184 there is an option to remember the esmtp state. Sigh.
5186 We must allow for an extra EHLO command and an extra AUTH command after
5187 STARTTLS that don't add to the nonmail command count. */
5189 if ((rc = tls_server_start(tls_require_ciphers)) == OK)
5191 if (!tls_remember_esmtp)
5192 helo_seen = esmtp = auth_advertised = pipelining_advertised = FALSE;
5193 cmd_list[CMD_LIST_EHLO].is_mail_cmd = TRUE;
5194 cmd_list[CMD_LIST_AUTH].is_mail_cmd = TRUE;
5195 cmd_list[CMD_LIST_TLS_AUTH].is_mail_cmd = TRUE;
5196 if (sender_helo_name != NULL)
5198 store_free(sender_helo_name);
5199 sender_helo_name = NULL;
5200 host_build_sender_fullhost(); /* Rebuild */
5201 set_process_info("handling incoming TLS connection from %s",
5202 host_and_ident(FALSE));
5205 (sender_host_address ? protocols : protocols_local)
5207 ? pextend + (sender_host_authenticated ? pauthed : 0)
5209 + (tls_in.active >= 0 ? pcrpted : 0)
5212 sender_host_authenticated = NULL;
5213 authenticated_id = NULL;
5214 sync_cmd_limit = NON_SYNC_CMD_NON_PIPELINING;
5215 DEBUG(D_tls) debug_printf("TLS active\n");
5216 break; /* Successful STARTTLS */
5219 /* Some local configuration problem was discovered before actually trying
5220 to do a TLS handshake; give a temporary error. */
5222 else if (rc == DEFER)
5224 smtp_printf("454 TLS currently unavailable\r\n");
5228 /* Hard failure. Reject everything except QUIT or closed connection. One
5229 cause for failure is a nested STARTTLS, in which case tls_in.active remains
5230 set, but we must still reject all incoming commands. */
5232 DEBUG(D_tls) debug_printf("TLS failed to start\n");
5233 while (done <= 0) switch(smtp_read_command(FALSE, GETC_BUFFER_UNLIMITED))
5236 log_write(L_smtp_connection, LOG_MAIN, "%s closed by EOF",
5237 smtp_get_connection_info());
5238 smtp_notquit_exit(US"tls-failed", NULL, NULL);
5242 /* It is perhaps arguable as to which exit ACL should be called here,
5243 but as it is probably a situation that almost never arises, it
5244 probably doesn't matter. We choose to call the real QUIT ACL, which in
5245 some sense is perhaps "right". */
5250 && ((rc = acl_check(ACL_WHERE_QUIT, NULL, acl_smtp_quit, &user_msg,
5251 &log_msg)) == ERROR))
5252 log_write(0, LOG_MAIN|LOG_PANIC, "ACL for QUIT returned ERROR: %s",
5255 smtp_respond(US"221", 3, TRUE, user_msg);
5257 smtp_printf("221 %s closing connection\r\n", smtp_active_hostname);
5258 log_write(L_smtp_connection, LOG_MAIN, "%s closed by QUIT",
5259 smtp_get_connection_info());
5264 smtp_printf("554 Security failure\r\n");
5267 tls_close(TRUE, TRUE);
5272 /* The ACL for QUIT is provided for gathering statistical information or
5273 similar; it does not affect the response code, but it can supply a custom
5277 smtp_quit_handler(&user_msg, &log_msg);
5283 smtp_rset_handler();
5284 smtp_reset(reset_point);
5291 smtp_printf("250 OK\r\n");
5295 /* Show ETRN/EXPN/VRFY if there's an ACL for checking hosts; if actually
5296 used, a check will be done for permitted hosts. Show STARTTLS only if not
5297 already in a TLS session and if it would be advertised in the EHLO
5302 smtp_printf("214-Commands supported:\r\n");
5306 Ustrcat(buffer, " AUTH");
5308 if (tls_in.active < 0 &&
5309 verify_check_host(&tls_advertise_hosts) != FAIL)
5310 Ustrcat(buffer, " STARTTLS");
5312 Ustrcat(buffer, " HELO EHLO MAIL RCPT DATA BDAT");
5313 Ustrcat(buffer, " NOOP QUIT RSET HELP");
5314 if (acl_smtp_etrn != NULL) Ustrcat(buffer, " ETRN");
5315 if (acl_smtp_expn != NULL) Ustrcat(buffer, " EXPN");
5316 if (acl_smtp_vrfy != NULL) Ustrcat(buffer, " VRFY");
5317 smtp_printf("214%s\r\n", buffer);
5323 incomplete_transaction_log(US"connection lost");
5324 smtp_notquit_exit(US"connection-lost", US"421",
5325 US"%s lost input connection", smtp_active_hostname);
5327 /* Don't log by default unless in the middle of a message, as some mailers
5328 just drop the call rather than sending QUIT, and it clutters up the logs.
5331 if (sender_address != NULL || recipients_count > 0)
5332 log_write(L_lost_incoming_connection,
5334 "unexpected %s while reading SMTP command from %s%s",
5335 sender_host_unknown? "EOF" : "disconnection",
5336 host_and_ident(FALSE), smtp_read_error);
5338 else log_write(L_smtp_connection, LOG_MAIN, "%s lost%s",
5339 smtp_get_connection_info(), smtp_read_error);
5347 if (sender_address != NULL)
5349 done = synprot_error(L_smtp_protocol_error, 503, NULL,
5350 US"ETRN is not permitted inside a transaction");
5354 log_write(L_etrn, LOG_MAIN, "ETRN %s received from %s", smtp_cmd_argument,
5355 host_and_ident(FALSE));
5357 if ((rc = acl_check(ACL_WHERE_ETRN, NULL, acl_smtp_etrn,
5358 &user_msg, &log_msg)) != OK)
5360 done = smtp_handle_acl_fail(ACL_WHERE_ETRN, rc, user_msg, log_msg);
5364 /* Compute the serialization key for this command. */
5366 etrn_serialize_key = string_sprintf("etrn-%s\n", smtp_cmd_data);
5368 /* If a command has been specified for running as a result of ETRN, we
5369 permit any argument to ETRN. If not, only the # standard form is permitted,
5370 since that is strictly the only kind of ETRN that can be implemented
5371 according to the RFC. */
5373 if (smtp_etrn_command != NULL)
5377 etrn_command = smtp_etrn_command;
5378 deliver_domain = smtp_cmd_data;
5379 rc = transport_set_up_command(&argv, smtp_etrn_command, TRUE, 0, NULL,
5380 US"ETRN processing", &error);
5381 deliver_domain = NULL;
5384 log_write(0, LOG_MAIN|LOG_PANIC, "failed to set up ETRN command: %s",
5386 smtp_printf("458 Internal failure\r\n");
5391 /* Else set up to call Exim with the -R option. */
5395 if (*smtp_cmd_data++ != '#')
5397 done = synprot_error(L_smtp_syntax_error, 501, NULL,
5398 US"argument must begin with #");
5401 etrn_command = US"exim -R";
5402 argv = CUSS child_exec_exim(CEE_RETURN_ARGV, TRUE, NULL, TRUE,
5403 *queue_name ? 4 : 2,
5404 US"-R", smtp_cmd_data,
5405 US"-MCG", queue_name);
5408 /* If we are host-testing, don't actually do anything. */
5414 debug_printf("ETRN command is: %s\n", etrn_command);
5415 debug_printf("ETRN command execution skipped\n");
5417 if (user_msg == NULL) smtp_printf("250 OK\r\n");
5418 else smtp_user_msg(US"250", user_msg);
5423 /* If ETRN queue runs are to be serialized, check the database to
5424 ensure one isn't already running. */
5426 if (smtp_etrn_serialize && !enq_start(etrn_serialize_key, 1))
5428 smtp_printf("458 Already processing %s\r\n", smtp_cmd_data);
5432 /* Fork a child process and run the command. We don't want to have to
5433 wait for the process at any point, so set SIGCHLD to SIG_IGN before
5434 forking. It should be set that way anyway for external incoming SMTP,
5435 but we save and restore to be tidy. If serialization is required, we
5436 actually run the command in yet another process, so we can wait for it
5437 to complete and then remove the serialization lock. */
5439 oldsignal = signal(SIGCHLD, SIG_IGN);
5441 if ((pid = fork()) == 0)
5443 smtp_input = FALSE; /* This process is not associated with the */
5444 (void)fclose(smtp_in); /* SMTP call any more. */
5445 (void)fclose(smtp_out);
5447 signal(SIGCHLD, SIG_DFL); /* Want to catch child */
5449 /* If not serializing, do the exec right away. Otherwise, fork down
5450 into another process. */
5452 if (!smtp_etrn_serialize || (pid = fork()) == 0)
5454 DEBUG(D_exec) debug_print_argv(argv);
5455 exim_nullstd(); /* Ensure std{in,out,err} exist */
5456 execv(CS argv[0], (char *const *)argv);
5457 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "exec of \"%s\" (ETRN) failed: %s",
5458 etrn_command, strerror(errno));
5459 _exit(EXIT_FAILURE); /* paranoia */
5462 /* Obey this if smtp_serialize and the 2nd fork yielded non-zero. That
5463 is, we are in the first subprocess, after forking again. All we can do
5464 for a failing fork is to log it. Otherwise, wait for the 2nd process to
5465 complete, before removing the serialization. */
5468 log_write(0, LOG_MAIN|LOG_PANIC, "2nd fork for serialized ETRN "
5469 "failed: %s", strerror(errno));
5473 DEBUG(D_any) debug_printf("waiting for serialized ETRN process %d\n",
5475 (void)wait(&status);
5476 DEBUG(D_any) debug_printf("serialized ETRN process %d ended\n",
5480 enq_end(etrn_serialize_key);
5481 _exit(EXIT_SUCCESS);
5484 /* Back in the top level SMTP process. Check that we started a subprocess
5485 and restore the signal state. */
5489 log_write(0, LOG_MAIN|LOG_PANIC, "fork of process for ETRN failed: %s",
5491 smtp_printf("458 Unable to fork process\r\n");
5492 if (smtp_etrn_serialize) enq_end(etrn_serialize_key);
5496 if (user_msg == NULL) smtp_printf("250 OK\r\n");
5497 else smtp_user_msg(US"250", user_msg);
5500 signal(SIGCHLD, oldsignal);
5505 done = synprot_error(L_smtp_syntax_error, 501, NULL,
5506 US"unexpected argument data");
5510 /* This currently happens only for NULLs, but could be extended. */
5513 done = synprot_error(L_smtp_syntax_error, 0, NULL, /* Just logs */
5514 US"NULL character(s) present (shown as '?')");
5515 smtp_printf("501 NULL characters are not allowed in SMTP commands\r\n");
5521 if (smtp_inend >= smtp_inbuffer + IN_BUFFER_SIZE)
5522 smtp_inend = smtp_inbuffer + IN_BUFFER_SIZE - 1;
5523 c = smtp_inend - smtp_inptr;
5524 if (c > 150) c = 150;
5526 incomplete_transaction_log(US"sync failure");
5527 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP protocol synchronization error "
5528 "(next input sent too soon: pipelining was%s advertised): "
5529 "rejected \"%s\" %s next input=\"%s\"",
5530 pipelining_advertised? "" : " not",
5531 smtp_cmd_buffer, host_and_ident(TRUE),
5532 string_printing(smtp_inptr));
5533 smtp_notquit_exit(US"synchronization-error", US"554",
5534 US"SMTP synchronization error");
5535 done = 1; /* Pretend eof - drops connection */
5539 case TOO_MANY_NONMAIL_CMD:
5540 s = smtp_cmd_buffer;
5541 while (*s != 0 && !isspace(*s)) s++;
5542 incomplete_transaction_log(US"too many non-mail commands");
5543 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
5544 "nonmail commands (last was \"%.*s\")", host_and_ident(FALSE),
5545 (int)(s - smtp_cmd_buffer), smtp_cmd_buffer);
5546 smtp_notquit_exit(US"bad-commands", US"554", US"Too many nonmail commands");
5547 done = 1; /* Pretend eof - drops connection */
5550 #ifdef SUPPORT_PROXY
5551 case PROXY_FAIL_IGNORE_CMD:
5552 smtp_printf("503 Command refused, required Proxy negotiation failed\r\n");
5557 if (unknown_command_count++ >= smtp_max_unknown_commands)
5559 log_write(L_smtp_syntax_error, LOG_MAIN,
5560 "SMTP syntax error in \"%s\" %s %s",
5561 string_printing(smtp_cmd_buffer), host_and_ident(TRUE),
5562 US"unrecognized command");
5563 incomplete_transaction_log(US"unrecognized command");
5564 smtp_notquit_exit(US"bad-commands", US"500",
5565 US"Too many unrecognized commands");
5567 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
5568 "unrecognized commands (last was \"%s\")", host_and_ident(FALSE),
5569 string_printing(smtp_cmd_buffer));
5572 done = synprot_error(L_smtp_syntax_error, 500, NULL,
5573 US"unrecognized command");
5577 /* This label is used by goto's inside loops that want to break out to
5578 the end of the command-processing loop. */
5581 last_was_rej_mail = was_rej_mail; /* Remember some last commands for */
5582 last_was_rcpt = was_rcpt; /* protocol error handling */
5586 return done - 2; /* Convert yield values */
5591 /* End of smtp_in.c */