1 /*************************************************
2 * Exim - an Internet mail transport agent *
3 *************************************************/
5 /* Copyright (c) University of Cambridge 1995 - 2018 */
6 /* See the file NOTICE for conditions of use and distribution. */
8 /* Functions for handling an incoming SMTP call. */
15 /* Initialize for TCP wrappers if so configured. It appears that the macro
16 HAVE_IPV6 is used in some versions of the tcpd.h header, so we unset it before
17 including that header, and restore its value afterwards. */
19 #ifdef USE_TCP_WRAPPERS
22 #define EXIM_HAVE_IPV6
28 #define HAVE_IPV6 TRUE
31 int allow_severity = LOG_INFO;
32 int deny_severity = LOG_NOTICE;
33 uschar *tcp_wrappers_name;
37 /* Size of buffer for reading SMTP commands. We used to use 512, as defined
38 by RFC 821. However, RFC 1869 specifies that this must be increased for SMTP
39 commands that accept arguments, and this in particular applies to AUTH, where
40 the data can be quite long. More recently this value was 2048 in Exim;
41 however, RFC 4954 (circa 2007) recommends 12288 bytes to handle AUTH. Clients
42 such as Thunderbird will send an AUTH with an initial-response for GSSAPI.
43 The maximum size of a Kerberos ticket under Windows 2003 is 12000 bytes, and
44 we need room to handle large base64-encoded AUTHs for GSSAPI.
47 #define SMTP_CMD_BUFFER_SIZE 16384
49 /* Size of buffer for reading SMTP incoming packets */
51 #define IN_BUFFER_SIZE 8192
53 /* Structure for SMTP command list */
60 short int is_mail_cmd;
63 /* Codes for identifying commands. We order them so that those that come first
64 are those for which synchronization is always required. Checking this can help
68 /* These commands are required to be synchronized, i.e. to be the last in a
69 block of commands when pipelining. */
71 HELO_CMD, EHLO_CMD, DATA_CMD, /* These are listed in the pipelining */
72 VRFY_CMD, EXPN_CMD, NOOP_CMD, /* RFC as requiring synchronization */
73 ETRN_CMD, /* This by analogy with TURN from the RFC */
74 STARTTLS_CMD, /* Required by the STARTTLS RFC */
75 TLS_AUTH_CMD, /* auto-command at start of SSL */
77 /* This is a dummy to identify the non-sync commands when pipelining */
79 NON_SYNC_CMD_PIPELINING,
81 /* These commands need not be synchronized when pipelining */
83 MAIL_CMD, RCPT_CMD, RSET_CMD,
85 /* This is a dummy to identify the non-sync commands when not pipelining */
87 NON_SYNC_CMD_NON_PIPELINING,
89 /* RFC3030 section 2: "After all MAIL and RCPT responses are collected and
90 processed the message is sent using a series of BDAT commands"
91 implies that BDAT should be synchronized. However, we see Google, at least,
92 sending MAIL,RCPT,BDAT-LAST in a single packet, clearly not waiting for
93 processing of the RCPT response(s). We shall do the same, and not require
94 synch for BDAT. Worse, as the chunk may (very likely will) follow the
95 command-header in the same packet we cannot do the usual "is there any
96 follow-on data after the command line" even for non-pipeline mode.
97 So we'll need an explicit check after reading the expected chunk amount
98 when non-pipe, before sending the ACK. */
102 /* I have been unable to find a statement about the use of pipelining
103 with AUTH, so to be on the safe side it is here, though I kind of feel
104 it should be up there with the synchronized commands. */
108 /* I'm not sure about these, but I don't think they matter. */
113 PROXY_FAIL_IGNORE_CMD,
116 /* These are specials that don't correspond to actual commands */
118 EOF_CMD, OTHER_CMD, BADARG_CMD, BADCHAR_CMD, BADSYN_CMD,
119 TOO_MANY_NONMAIL_CMD };
122 /* This is a convenience macro for adding the identity of an SMTP command
123 to the circular buffer that holds a list of the last n received. */
126 smtp_connection_had[smtp_ch_index++] = n; \
127 if (smtp_ch_index >= SMTP_HBUFF_SIZE) smtp_ch_index = 0
130 /*************************************************
131 * Local static variables *
132 *************************************************/
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, FALSE },
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 static int smtp_read_command(BOOL check_sync, unsigned buffer_lim);
308 static int synprot_error(int type, int code, uschar *data, uschar *errmess);
309 static void smtp_quit_handler(uschar **, uschar **);
310 static void smtp_rset_handler(void);
312 /*************************************************
313 * Recheck synchronization *
314 *************************************************/
316 /* Synchronization checks can never be perfect because a packet may be on its
317 way but not arrived when the check is done. Normally, the checks happen when
318 commands are read: Exim ensures that there is no more input in the input buffer.
319 In normal cases, the response to the command will be fast, and there is no
322 However, for some commands an ACL is run, and that can include delays. In those
323 cases, it is useful to do another check on the input just before sending the
324 response. This also applies at the start of a connection. This function does
325 that check by means of the select() function, as long as the facility is not
326 disabled or inappropriate. A failure of select() is ignored.
328 When there is unwanted input, we read it so that it appears in the log of the
332 Returns: TRUE if all is well; FALSE if there is input pending
336 wouldblock_reading(void)
340 struct timeval tzero;
343 if (tls_in.active >= 0)
344 return !tls_could_read();
347 if (smtp_inptr < smtp_inend)
350 fd = fileno(smtp_in);
355 rc = select(fd + 1, (SELECT_ARG2_TYPE *)&fds, NULL, NULL, &tzero);
357 if (rc <= 0) return TRUE; /* Not ready to read */
358 rc = smtp_getc(GETC_BUFFER_UNLIMITED);
359 if (rc < 0) return TRUE; /* End of file or error */
362 rc = smtp_inend - smtp_inptr;
363 if (rc > 150) rc = 150;
371 if (!smtp_enforce_sync || sender_host_address == NULL || sender_host_notsocket)
374 return wouldblock_reading();
378 /* If there's input waiting (and we're doing pipelineing) then we can pipeline
379 a reponse with the one following. */
382 pipeline_response(void)
384 if ( !smtp_enforce_sync || !sender_host_address
385 || sender_host_notsocket || !pipelining_advertised)
388 return !wouldblock_reading();
393 /*************************************************
394 * Log incomplete transactions *
395 *************************************************/
397 /* This function is called after a transaction has been aborted by RSET, QUIT,
398 connection drops or other errors. It logs the envelope information received
399 so far in order to preserve address verification attempts.
401 Argument: string to indicate what aborted the transaction
406 incomplete_transaction_log(uschar *what)
408 if (sender_address == NULL || /* No transaction in progress */
409 !LOGGING(smtp_incomplete_transaction))
412 /* Build list of recipients for logging */
414 if (recipients_count > 0)
417 raw_recipients = store_get(recipients_count * sizeof(uschar *));
418 for (i = 0; i < recipients_count; i++)
419 raw_recipients[i] = recipients_list[i].address;
420 raw_recipients_count = recipients_count;
423 log_write(L_smtp_incomplete_transaction, LOG_MAIN|LOG_SENDER|LOG_RECIPIENTS,
424 "%s incomplete transaction (%s)", host_and_ident(TRUE), what);
431 smtp_command_timeout_exit(void)
433 log_write(L_lost_incoming_connection,
434 LOG_MAIN, "SMTP command timeout on%s connection from %s",
435 tls_in.active >= 0 ? " TLS" : "", host_and_ident(FALSE));
436 if (smtp_batched_input)
437 moan_smtp_batch(NULL, "421 SMTP command timeout"); /* Does not return */
438 smtp_notquit_exit(US"command-timeout", US"421",
439 US"%s: SMTP command timeout - closing connection",
440 smtp_active_hostname);
441 exim_exit(EXIT_FAILURE, US"receiving");
445 smtp_command_sigterm_exit(void)
447 log_write(0, LOG_MAIN, "%s closed after SIGTERM", smtp_get_connection_info());
448 if (smtp_batched_input)
449 moan_smtp_batch(NULL, "421 SIGTERM received"); /* Does not return */
450 smtp_notquit_exit(US"signal-exit", US"421",
451 US"%s: Service not available - closing connection", smtp_active_hostname);
452 exim_exit(EXIT_FAILURE, US"receiving");
456 smtp_data_timeout_exit(void)
458 log_write(L_lost_incoming_connection,
459 LOG_MAIN, "SMTP data timeout (message abandoned) on connection from %s F=<%s>",
460 sender_fullhost ? sender_fullhost : US"local process", sender_address);
461 receive_bomb_out(US"data-timeout", US"SMTP incoming data timeout");
462 /* Does not return */
466 smtp_data_sigint_exit(void)
468 log_write(0, LOG_MAIN, "%s closed after %s",
469 smtp_get_connection_info(), had_data_sigint == SIGTERM ? "SIGTERM":"SIGINT");
470 receive_bomb_out(US"signal-exit",
471 US"Service not available - SIGTERM or SIGINT received");
472 /* Does not return */
477 /* Refill the buffer, and notify DKIM verification code.
478 Return false for error or EOF.
482 smtp_refill(unsigned lim)
485 if (!smtp_out) return FALSE;
487 if (smtp_receive_timeout > 0) alarm(smtp_receive_timeout);
489 /* Limit amount read, so non-message data is not fed to DKIM */
491 rc = read(fileno(smtp_in), smtp_inbuffer, MIN(IN_BUFFER_SIZE, lim));
493 if (smtp_receive_timeout > 0) alarm(0);
496 /* Must put the error text in fixed store, because this might be during
497 header reading, where it releases unused store above the header. */
500 if (had_command_timeout) /* set by signal handler */
501 smtp_command_timeout_exit(); /* does not return */
502 if (had_command_sigterm)
503 smtp_command_sigterm_exit();
504 if (had_data_timeout)
505 smtp_data_timeout_exit();
507 smtp_data_sigint_exit();
509 smtp_had_error = save_errno;
510 smtp_read_error = string_copy_malloc(
511 string_sprintf(" (error: %s)", strerror(save_errno)));
518 dkim_exim_verify_feed(smtp_inbuffer, rc);
520 smtp_inend = smtp_inbuffer + rc;
521 smtp_inptr = smtp_inbuffer;
525 /*************************************************
526 * SMTP version of getc() *
527 *************************************************/
529 /* This gets the next byte from the SMTP input buffer. If the buffer is empty,
530 it flushes the output, and refills the buffer, with a timeout. The signal
531 handler is set appropriately by the calling function. This function is not used
532 after a connection has negotiated itself into an TLS/SSL state.
534 Arguments: lim Maximum amount to read/buffer
535 Returns: the next character or EOF
539 smtp_getc(unsigned lim)
541 if (smtp_inptr >= smtp_inend)
542 if (!smtp_refill(lim))
544 return *smtp_inptr++;
548 smtp_getbuf(unsigned * len)
553 if (smtp_inptr >= smtp_inend)
554 if (!smtp_refill(*len))
555 { *len = 0; return NULL; }
557 if ((size = smtp_inend - smtp_inptr) > *len) size = *len;
568 int n = smtp_inend - smtp_inptr;
570 dkim_exim_verify_feed(smtp_inptr, n);
575 /* Get a byte from the smtp input, in CHUNKING mode. Handle ack of the
576 previous BDAT chunk and getting new ones when we run out. Uses the
577 underlying smtp_getc or tls_getc both for that and for getting the
578 (buffered) data byte. EOD signals (an expected) no further data.
579 ERR signals a protocol error, and EOF a closed input stream.
581 Called from read_bdat_smtp() in receive.c for the message body, but also
582 by the headers read loop in receive_msg(); manipulates chunking_state
583 to handle the BDAT command/response.
584 Placed here due to the correlation with the above smtp_getc(), which it wraps,
585 and also by the need to do smtp command/response handling.
587 Arguments: lim (ignored)
588 Returns: the next character or ERR, EOD or EOF
592 bdat_getc(unsigned lim)
594 uschar * user_msg = NULL;
603 if (chunking_data_left > 0)
604 return lwr_receive_getc(chunking_data_left--);
606 receive_getc = lwr_receive_getc;
607 receive_getbuf = lwr_receive_getbuf;
608 receive_ungetc = lwr_receive_ungetc;
610 dkim_save = dkim_collect_input;
611 dkim_collect_input = FALSE;
614 /* Unless PIPELINING was offered, there should be no next command
615 until after we ack that chunk */
617 if (!pipelining_advertised && !check_sync())
619 unsigned n = smtp_inend - smtp_inptr;
622 incomplete_transaction_log(US"sync failure");
623 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP protocol synchronization error "
624 "(next input sent too soon: pipelining was not advertised): "
625 "rejected \"%s\" %s next input=\"%s\"%s",
626 smtp_cmd_buffer, host_and_ident(TRUE),
627 string_printing(string_copyn(smtp_inptr, n)),
628 smtp_inend - smtp_inptr > n ? "..." : "");
629 (void) synprot_error(L_smtp_protocol_error, 554, NULL,
630 US"SMTP synchronization error");
631 goto repeat_until_rset;
634 /* If not the last, ack the received chunk. The last response is delayed
635 until after the data ACL decides on it */
637 if (chunking_state == CHUNKING_LAST)
640 dkim_exim_verify_feed(NULL, 0); /* notify EOD */
645 smtp_printf("250 %u byte chunk received\r\n", FALSE, chunking_datasize);
646 chunking_state = CHUNKING_OFFERED;
647 DEBUG(D_receive) debug_printf("chunking state %d\n", (int)chunking_state);
649 /* Expect another BDAT cmd from input. RFC 3030 says nothing about
650 QUIT, RSET or NOOP but handling them seems obvious */
653 switch(smtp_read_command(TRUE, 1))
656 (void) synprot_error(L_smtp_protocol_error, 503, NULL,
657 US"only BDAT permissible after non-LAST BDAT");
660 switch(smtp_read_command(TRUE, 1))
662 case QUIT_CMD: smtp_quit_handler(&user_msg, &log_msg); /*FALLTHROUGH */
663 case EOF_CMD: return EOF;
664 case RSET_CMD: smtp_rset_handler(); return ERR;
665 default: if (synprot_error(L_smtp_protocol_error, 503, NULL,
666 US"only RSET accepted now") > 0)
668 goto repeat_until_rset;
672 smtp_quit_handler(&user_msg, &log_msg);
683 smtp_printf("250 OK\r\n", FALSE);
690 if (sscanf(CS smtp_cmd_data, "%u %n", &chunking_datasize, &n) < 1)
692 (void) synprot_error(L_smtp_protocol_error, 501, NULL,
693 US"missing size for BDAT command");
696 chunking_state = strcmpic(smtp_cmd_data+n, US"LAST") == 0
697 ? CHUNKING_LAST : CHUNKING_ACTIVE;
698 chunking_data_left = chunking_datasize;
699 DEBUG(D_receive) debug_printf("chunking state %d, %d bytes\n",
700 (int)chunking_state, chunking_data_left);
702 if (chunking_datasize == 0)
703 if (chunking_state == CHUNKING_LAST)
707 (void) synprot_error(L_smtp_protocol_error, 504, NULL,
708 US"zero size for BDAT command");
709 goto repeat_until_rset;
712 receive_getc = bdat_getc;
713 receive_getbuf = bdat_getbuf; /* r~getbuf is never actually used */
714 receive_ungetc = bdat_ungetc;
716 dkim_collect_input = dkim_save;
718 break; /* to top of main loop */
725 bdat_getbuf(unsigned * len)
729 if (chunking_data_left <= 0)
730 { *len = 0; return NULL; }
732 if (*len > chunking_data_left) *len = chunking_data_left;
733 buf = lwr_receive_getbuf(len); /* Either smtp_getbuf or tls_getbuf */
734 chunking_data_left -= *len;
739 bdat_flush_data(void)
741 while (chunking_data_left)
743 unsigned n = chunking_data_left;
744 if (!bdat_getbuf(&n)) break;
747 receive_getc = lwr_receive_getc;
748 receive_getbuf = lwr_receive_getbuf;
749 receive_ungetc = lwr_receive_ungetc;
751 if (chunking_state != CHUNKING_LAST)
753 chunking_state = CHUNKING_OFFERED;
754 DEBUG(D_receive) debug_printf("chunking state %d\n", (int)chunking_state);
761 /*************************************************
762 * SMTP version of ungetc() *
763 *************************************************/
765 /* Puts a character back in the input buffer. Only ever
771 Returns: the character
785 chunking_data_left++;
786 return lwr_receive_ungetc(ch);
791 /*************************************************
792 * SMTP version of feof() *
793 *************************************************/
795 /* Tests for a previous EOF
798 Returns: non-zero if the eof flag is set
810 /*************************************************
811 * SMTP version of ferror() *
812 *************************************************/
814 /* Tests for a previous read error, and returns with errno
815 restored to what it was when the error was detected.
818 Returns: non-zero if the error flag is set
824 errno = smtp_had_error;
825 return smtp_had_error;
830 /*************************************************
831 * Test for characters in the SMTP buffer *
832 *************************************************/
834 /* Used at the end of a message
843 return smtp_inptr < smtp_inend;
848 /*************************************************
849 * Write formatted string to SMTP channel *
850 *************************************************/
852 /* This is a separate function so that we don't have to repeat everything for
853 TLS support or debugging. It is global so that the daemon and the
854 authentication functions can use it. It does not return any error indication,
855 because major problems such as dropped connections won't show up till an output
856 flush for non-TLS connections. The smtp_fflush() function is available for
857 checking that: for convenience, TLS output errors are remembered here so that
858 they are also picked up later by smtp_fflush().
862 more further data expected
863 ... optional arguments
869 smtp_printf(const char *format, BOOL more, ...)
874 smtp_vprintf(format, more, ap);
878 /* This is split off so that verify.c:respond_printf() can, in effect, call
879 smtp_printf(), bearing in mind that in C a vararg function can't directly
880 call another vararg function, only a function which accepts a va_list. */
883 smtp_vprintf(const char *format, BOOL more, va_list ap)
887 yield = string_vformat(big_buffer, big_buffer_size, format, ap);
891 void *reset_point = store_get(0);
892 uschar *msg_copy, *cr, *end;
893 msg_copy = string_copy(big_buffer);
894 end = msg_copy + Ustrlen(msg_copy);
895 while ((cr = Ustrchr(msg_copy, '\r')) != NULL) /* lose CRs */
896 memmove(cr, cr + 1, (end--) - cr);
897 debug_printf("SMTP>> %s", msg_copy);
898 store_reset(reset_point);
903 log_write(0, LOG_MAIN|LOG_PANIC, "string too large in smtp_printf()");
904 smtp_closedown(US"Unexpected error");
905 exim_exit(EXIT_FAILURE, NULL);
908 /* If this is the first output for a (non-batch) RCPT command, see if all RCPTs
909 have had the same. Note: this code is also present in smtp_respond(). It would
910 be tidier to have it only in one place, but when it was added, it was easier to
911 do it that way, so as not to have to mess with the code for the RCPT command,
912 which sometimes uses smtp_printf() and sometimes smtp_respond(). */
914 if (rcpt_in_progress)
916 if (rcpt_smtp_response == NULL)
917 rcpt_smtp_response = string_copy(big_buffer);
918 else if (rcpt_smtp_response_same &&
919 Ustrcmp(rcpt_smtp_response, big_buffer) != 0)
920 rcpt_smtp_response_same = FALSE;
921 rcpt_in_progress = FALSE;
924 /* Now write the string */
927 if (tls_in.active >= 0)
929 if (tls_write(TRUE, big_buffer, Ustrlen(big_buffer), more) < 0)
930 smtp_write_error = -1;
935 if (fprintf(smtp_out, "%s", big_buffer) < 0) smtp_write_error = -1;
940 /*************************************************
941 * Flush SMTP out and check for error *
942 *************************************************/
944 /* This function isn't currently used within Exim (it detects errors when it
945 tries to read the next SMTP input), but is available for use in local_scan().
946 For non-TLS connections, it flushes the output and checks for errors. For
947 TLS-connections, it checks for a previously-detected TLS write error.
950 Returns: 0 for no error; -1 after an error
956 if (tls_in.active < 0 && fflush(smtp_out) != 0) smtp_write_error = -1;
957 return smtp_write_error;
962 /*************************************************
963 * SMTP command read timeout *
964 *************************************************/
966 /* Signal handler for timing out incoming SMTP commands. This attempts to
969 Argument: signal number (SIGALRM)
974 command_timeout_handler(int sig)
976 had_command_timeout = sig;
981 /*************************************************
983 *************************************************/
985 /* Signal handler for handling SIGTERM. Again, try to finish tidily.
987 Argument: signal number (SIGTERM)
992 command_sigterm_handler(int sig)
994 had_command_sigterm = sig;
1000 #ifdef SUPPORT_PROXY
1001 /*************************************************
1002 * Restore socket timeout to previous value *
1003 *************************************************/
1004 /* If the previous value was successfully retrieved, restore
1005 it before returning control to the non-proxy routines
1007 Arguments: fd - File descriptor for input
1008 get_ok - Successfully retrieved previous values
1009 tvtmp - Time struct with previous values
1010 vslen - Length of time struct
1014 restore_socket_timeout(int fd, int get_ok, struct timeval * tvtmp, socklen_t vslen)
1017 (void) setsockopt(fd, SOL_SOCKET, SO_RCVTIMEO, CS tvtmp, vslen);
1020 /*************************************************
1021 * Check if host is required proxy host *
1022 *************************************************/
1023 /* The function determines if inbound host will be a regular smtp host
1024 or if it is configured that it must use Proxy Protocol. A local
1032 check_proxy_protocol_host()
1036 if ( sender_host_address
1037 && (rc = verify_check_this_host(CUSS &hosts_proxy, NULL, NULL,
1038 sender_host_address, NULL)) == OK)
1041 debug_printf("Detected proxy protocol configured host\n");
1042 proxy_session = TRUE;
1044 return proxy_session;
1048 /*************************************************
1049 * Read data until newline or end of buffer *
1050 *************************************************/
1051 /* While SMTP is server-speaks-first, TLS is client-speaks-first, so we can't
1052 read an entire buffer and assume there will be nothing past a proxy protocol
1053 header. Our approach normally is to use stdio, but again that relies upon
1054 "STARTTLS\r\n" and a server response before the client starts TLS handshake, or
1055 reading _nothing_ before client TLS handshake. So we don't want to use the
1056 usual buffering reads which may read enough to block TLS starting.
1058 So unfortunately we're down to "read one byte at a time, with a syscall each,
1059 and expect a little overhead", for all proxy-opened connections which are v1,
1060 just to handle the TLS-on-connect case. Since SSL functions wrap the
1061 underlying fd, we can't assume that we can feed them any already-read content.
1063 We need to know where to read to, the max capacity, and we'll read until we
1064 get a CR and one more character. Let the caller scream if it's CR+!LF.
1066 Return the amount read.
1070 swallow_until_crlf(int fd, uschar *base, int already, int capacity)
1072 uschar *to = base + already;
1078 /* For "PROXY UNKNOWN\r\n" we, at time of writing, expect to have read
1079 up through the \r; for the _normal_ case, we haven't yet seen the \r. */
1081 cr = memchr(base, '\r', already);
1084 if ((cr - base) < already - 1)
1086 /* \r and presumed \n already within what we have; probably not
1087 actually proxy protocol, but abort cleanly. */
1090 /* \r is last character read, just need one more. */
1094 while (capacity > 0)
1096 do { ret = recv(fd, to, 1, 0); } while (ret == -1 && errno == EINTR);
1108 /* reached end without having room for a final newline, abort */
1113 /*************************************************
1114 * Setup host for proxy protocol *
1115 *************************************************/
1116 /* The function configures the connection based on a header from the
1117 inbound host to use Proxy Protocol. The specification is very exact
1118 so exit with an error if do not find the exact required pieces. This
1119 includes an incorrect number of spaces separating args.
1122 Returns: Boolean success
1126 setup_proxy_protocol_host()
1138 struct { /* TCP/UDP over IPv4, len = 12 */
1144 struct { /* TCP/UDP over IPv6, len = 36 */
1145 uint8_t src_addr[16];
1146 uint8_t dst_addr[16];
1150 struct { /* AF_UNIX sockets, len = 216 */
1151 uschar src_addr[108];
1152 uschar dst_addr[108];
1158 /* Temp variables used in PPv2 address:port parsing */
1160 char tmpip[INET_ADDRSTRLEN];
1161 struct sockaddr_in tmpaddr;
1162 char tmpip6[INET6_ADDRSTRLEN];
1163 struct sockaddr_in6 tmpaddr6;
1165 /* We can't read "all data until end" because while SMTP is
1166 server-speaks-first, the TLS handshake is client-speaks-first, so for
1167 TLS-on-connect ports the proxy protocol header will usually be immediately
1168 followed by a TLS handshake, and with N TLS libraries, we can't reliably
1169 reinject data for reading by those. So instead we first read "enough to be
1170 safely read within the header, and figure out how much more to read".
1171 For v1 we will later read to the end-of-line, for v2 we will read based upon
1174 The v2 sig is 12 octets, and another 4 gets us the length, so we know how much
1175 data is needed total. For v1, where the line looks like:
1176 PROXY TCPn L3src L3dest SrcPort DestPort \r\n
1178 However, for v1 there's also `PROXY UNKNOWN\r\n` which is only 15 octets.
1179 We seem to support that. So, if we read 14 octets then we can tell if we're
1180 v2 or v1. If we're v1, we can continue reading as normal.
1182 If we're v2, we can't slurp up the entire header. We need the length in the
1183 15th & 16th octets, then to read everything after that.
1185 So to safely handle v1 and v2, with client-sent-first supported correctly,
1186 we have to do a minimum of 3 read calls, not 1. Eww.
1189 #define PROXY_INITIAL_READ 14
1190 #define PROXY_V2_HEADER_SIZE 16
1191 #if PROXY_INITIAL_READ > PROXY_V2_HEADER_SIZE
1192 # error Code bug in sizes of data to read for proxy usage
1197 int fd = fileno(smtp_in);
1198 const char v2sig[12] = "\x0D\x0A\x0D\x0A\x00\x0D\x0A\x51\x55\x49\x54\x0A";
1199 uschar * iptype; /* To display debug info */
1201 struct timeval tvtmp;
1202 socklen_t vslen = sizeof(struct timeval);
1205 /* Save current socket timeout values */
1206 get_ok = getsockopt(fd, SOL_SOCKET, SO_RCVTIMEO, CS &tvtmp, &vslen);
1208 /* Proxy Protocol host must send header within a short time
1209 (default 3 seconds) or it's considered invalid */
1210 tv.tv_sec = PROXY_NEGOTIATION_TIMEOUT_SEC;
1211 tv.tv_usec = PROXY_NEGOTIATION_TIMEOUT_USEC;
1212 if (setsockopt(fd, SOL_SOCKET, SO_RCVTIMEO, CS &tv, sizeof(tv)) < 0)
1217 /* The inbound host was declared to be a Proxy Protocol host, so
1218 don't do a PEEK into the data, actually slurp up enough to be
1219 "safe". Can't take it all because TLS-on-connect clients follow
1220 immediately with TLS handshake. */
1221 ret = recv(fd, &hdr, PROXY_INITIAL_READ, 0);
1223 while (ret == -1 && errno == EINTR);
1228 /* For v2, handle reading the length, and then the rest. */
1229 if ((ret == PROXY_INITIAL_READ) && (memcmp(&hdr.v2, v2sig, sizeof(v2sig)) == 0))
1234 /* First get the length fields. */
1237 retmore = recv(fd, (uschar*)&hdr + ret, PROXY_V2_HEADER_SIZE - PROXY_INITIAL_READ, 0);
1238 } while (retmore == -1 && errno == EINTR);
1243 ver = (hdr.v2.ver_cmd & 0xf0) >> 4;
1245 /* May 2014: haproxy combined the version and command into one byte to
1246 allow two full bytes for the length field in order to proxy SSL
1247 connections. SSL Proxy is not supported in this version of Exim, but
1248 must still separate values here. */
1252 DEBUG(D_receive) debug_printf("Invalid Proxy Protocol version: %d\n", ver);
1256 /* The v2 header will always be 16 bytes per the spec. */
1257 size = 16 + ntohs(hdr.v2.len);
1258 DEBUG(D_receive) debug_printf("Detected PROXYv2 header, size %d (limit %d)\n",
1259 size, (int)sizeof(hdr));
1261 /* We should now have 16 octets (PROXY_V2_HEADER_SIZE), and we know the total
1262 amount that we need. Double-check that the size is not unreasonable, then
1264 if (size > sizeof(hdr))
1266 DEBUG(D_receive) debug_printf("PROXYv2 header size unreasonably large; security attack?\n");
1274 retmore = recv(fd, (uschar*)&hdr + ret, size-ret, 0);
1275 } while (retmore == -1 && errno == EINTR);
1279 DEBUG(D_receive) debug_printf("PROXYv2: have %d/%d required octets\n", ret, size);
1280 } while (ret < size);
1282 } /* end scope for getting rest of data for v2 */
1284 /* At this point: if PROXYv2, we've read the exact size required for all data;
1285 if PROXYv1 then we've read "less than required for any valid line" and should
1288 if (ret >= 16 && memcmp(&hdr.v2, v2sig, 12) == 0)
1290 uint8_t cmd = (hdr.v2.ver_cmd & 0x0f);
1294 case 0x01: /* PROXY command */
1297 case 0x11: /* TCPv4 address type */
1299 tmpaddr.sin_addr.s_addr = hdr.v2.addr.ip4.src_addr;
1300 inet_ntop(AF_INET, &tmpaddr.sin_addr, CS &tmpip, sizeof(tmpip));
1301 if (!string_is_ip_address(US tmpip, NULL))
1303 DEBUG(D_receive) debug_printf("Invalid %s source IP\n", iptype);
1306 proxy_local_address = sender_host_address;
1307 sender_host_address = string_copy(US tmpip);
1308 tmpport = ntohs(hdr.v2.addr.ip4.src_port);
1309 proxy_local_port = sender_host_port;
1310 sender_host_port = tmpport;
1311 /* Save dest ip/port */
1312 tmpaddr.sin_addr.s_addr = hdr.v2.addr.ip4.dst_addr;
1313 inet_ntop(AF_INET, &tmpaddr.sin_addr, CS &tmpip, sizeof(tmpip));
1314 if (!string_is_ip_address(US tmpip, NULL))
1316 DEBUG(D_receive) debug_printf("Invalid %s dest port\n", iptype);
1319 proxy_external_address = string_copy(US tmpip);
1320 tmpport = ntohs(hdr.v2.addr.ip4.dst_port);
1321 proxy_external_port = tmpport;
1323 case 0x21: /* TCPv6 address type */
1325 memmove(tmpaddr6.sin6_addr.s6_addr, hdr.v2.addr.ip6.src_addr, 16);
1326 inet_ntop(AF_INET6, &tmpaddr6.sin6_addr, CS &tmpip6, sizeof(tmpip6));
1327 if (!string_is_ip_address(US tmpip6, NULL))
1329 DEBUG(D_receive) debug_printf("Invalid %s source IP\n", iptype);
1332 proxy_local_address = sender_host_address;
1333 sender_host_address = string_copy(US tmpip6);
1334 tmpport = ntohs(hdr.v2.addr.ip6.src_port);
1335 proxy_local_port = sender_host_port;
1336 sender_host_port = tmpport;
1337 /* Save dest ip/port */
1338 memmove(tmpaddr6.sin6_addr.s6_addr, hdr.v2.addr.ip6.dst_addr, 16);
1339 inet_ntop(AF_INET6, &tmpaddr6.sin6_addr, CS &tmpip6, sizeof(tmpip6));
1340 if (!string_is_ip_address(US tmpip6, NULL))
1342 DEBUG(D_receive) debug_printf("Invalid %s dest port\n", iptype);
1345 proxy_external_address = string_copy(US tmpip6);
1346 tmpport = ntohs(hdr.v2.addr.ip6.dst_port);
1347 proxy_external_port = tmpport;
1351 debug_printf("Unsupported PROXYv2 connection type: 0x%02x\n",
1355 /* Unsupported protocol, keep local connection address */
1357 case 0x00: /* LOCAL command */
1358 /* Keep local connection address for LOCAL */
1363 debug_printf("Unsupported PROXYv2 command: 0x%x\n", cmd);
1367 else if (ret >= 8 && memcmp(hdr.v1.line, "PROXY", 5) == 0)
1371 uschar *sp; /* Utility variables follow */
1376 /* get the rest of the line */
1377 r2 = swallow_until_crlf(fd, (uschar*)&hdr, ret, sizeof(hdr)-ret);
1382 p = string_copy(hdr.v1.line);
1383 end = memchr(p, '\r', ret - 1);
1385 if (!end || (end == (uschar*)&hdr + ret) || end[1] != '\n')
1387 DEBUG(D_receive) debug_printf("Partial or invalid PROXY header\n");
1390 *end = '\0'; /* Terminate the string */
1391 size = end + 2 - p; /* Skip header + CRLF */
1392 DEBUG(D_receive) debug_printf("Detected PROXYv1 header\n");
1393 DEBUG(D_receive) debug_printf("Bytes read not within PROXY header: %d\n", ret - size);
1394 /* Step through the string looking for the required fields. Ensure
1395 strict adherence to required formatting, exit for any error. */
1397 if (!isspace(*(p++)))
1399 DEBUG(D_receive) debug_printf("Missing space after PROXY command\n");
1402 if (!Ustrncmp(p, CCS"TCP4", 4))
1404 else if (!Ustrncmp(p,CCS"TCP6", 4))
1406 else if (!Ustrncmp(p,CCS"UNKNOWN", 7))
1408 iptype = US"Unknown";
1413 DEBUG(D_receive) debug_printf("Invalid TCP type\n");
1417 p += Ustrlen(iptype);
1418 if (!isspace(*(p++)))
1420 DEBUG(D_receive) debug_printf("Missing space after TCP4/6 command\n");
1423 /* Find the end of the arg */
1424 if ((sp = Ustrchr(p, ' ')) == NULL)
1427 debug_printf("Did not find proxied src %s\n", iptype);
1431 if(!string_is_ip_address(p, NULL))
1434 debug_printf("Proxied src arg is not an %s address\n", iptype);
1437 proxy_local_address = sender_host_address;
1438 sender_host_address = p;
1440 if ((sp = Ustrchr(p, ' ')) == NULL)
1443 debug_printf("Did not find proxy dest %s\n", iptype);
1447 if(!string_is_ip_address(p, NULL))
1450 debug_printf("Proxy dest arg is not an %s address\n", iptype);
1453 proxy_external_address = p;
1455 if ((sp = Ustrchr(p, ' ')) == NULL)
1457 DEBUG(D_receive) debug_printf("Did not find proxied src port\n");
1461 tmp_port = strtol(CCS p, &endc, 10);
1462 if (*endc || tmp_port == 0)
1465 debug_printf("Proxied src port '%s' not an integer\n", p);
1468 proxy_local_port = sender_host_port;
1469 sender_host_port = tmp_port;
1471 if ((sp = Ustrchr(p, '\0')) == NULL)
1473 DEBUG(D_receive) debug_printf("Did not find proxy dest port\n");
1476 tmp_port = strtol(CCS p, &endc, 10);
1477 if (*endc || tmp_port == 0)
1480 debug_printf("Proxy dest port '%s' not an integer\n", p);
1483 proxy_external_port = tmp_port;
1484 /* Already checked for /r /n above. Good V1 header received. */
1488 /* Wrong protocol */
1489 DEBUG(D_receive) debug_printf("Invalid proxy protocol version negotiation\n");
1490 (void) swallow_until_crlf(fd, (uschar*)&hdr, ret, sizeof(hdr)-ret);
1496 debug_printf("Valid %s sender from Proxy Protocol header\n", iptype);
1497 yield = proxy_session;
1499 /* Don't flush any potential buffer contents. Any input on proxyfail
1500 should cause a synchronization failure */
1503 restore_socket_timeout(fd, get_ok, &tvtmp, vslen);
1508 sender_host_name = NULL;
1509 (void) host_name_lookup();
1510 host_build_sender_fullhost();
1514 proxy_session_failed = TRUE;
1516 debug_printf("Failure to extract proxied host, only QUIT allowed\n");
1523 /*************************************************
1524 * Read one command line *
1525 *************************************************/
1527 /* Strictly, SMTP commands coming over the net are supposed to end with CRLF.
1528 There are sites that don't do this, and in any case internal SMTP probably
1529 should check only for LF. Consequently, we check here for LF only. The line
1530 ends up with [CR]LF removed from its end. If we get an overlong line, treat as
1531 an unknown command. The command is read into the global smtp_cmd_buffer so that
1532 it is available via $smtp_command.
1534 The character reading routine sets up a timeout for each block actually read
1535 from the input (which may contain more than one command). We set up a special
1536 signal handler that closes down the session on a timeout. Control does not
1537 return when it runs.
1540 check_sync if TRUE, check synchronization rules if global option is TRUE
1541 buffer_lim maximum to buffer in lower layer
1543 Returns: a code identifying the command (enumerated above)
1547 smtp_read_command(BOOL check_sync, unsigned buffer_lim)
1552 BOOL hadnull = FALSE;
1554 had_command_timeout = 0;
1555 os_non_restarting_signal(SIGALRM, command_timeout_handler);
1557 while ((c = (receive_getc)(buffer_lim)) != '\n' && c != EOF)
1559 if (ptr >= SMTP_CMD_BUFFER_SIZE)
1561 os_non_restarting_signal(SIGALRM, sigalrm_handler);
1569 smtp_cmd_buffer[ptr++] = c;
1572 receive_linecount++; /* For BSMTP errors */
1573 os_non_restarting_signal(SIGALRM, sigalrm_handler);
1575 /* If hit end of file, return pseudo EOF command. Whether we have a
1576 part-line already read doesn't matter, since this is an error state. */
1578 if (c == EOF) return EOF_CMD;
1580 /* Remove any CR and white space at the end of the line, and terminate the
1583 while (ptr > 0 && isspace(smtp_cmd_buffer[ptr-1])) ptr--;
1584 smtp_cmd_buffer[ptr] = 0;
1586 DEBUG(D_receive) debug_printf("SMTP<< %s\n", smtp_cmd_buffer);
1588 /* NULLs are not allowed in SMTP commands */
1590 if (hadnull) return BADCHAR_CMD;
1592 /* Scan command list and return identity, having set the data pointer
1593 to the start of the actual data characters. Check for SMTP synchronization
1596 for (p = cmd_list; p < cmd_list_end; p++)
1598 #ifdef SUPPORT_PROXY
1599 /* Only allow QUIT command if Proxy Protocol parsing failed */
1600 if (proxy_session && proxy_session_failed && p->cmd != QUIT_CMD)
1604 && strncmpic(smtp_cmd_buffer, US p->name, p->len) == 0
1605 && ( smtp_cmd_buffer[p->len-1] == ':' /* "mail from:" or "rcpt to:" */
1606 || smtp_cmd_buffer[p->len] == 0
1607 || smtp_cmd_buffer[p->len] == ' '
1610 if (smtp_inptr < smtp_inend && /* Outstanding input */
1611 p->cmd < sync_cmd_limit && /* Command should sync */
1612 check_sync && /* Local flag set */
1613 smtp_enforce_sync && /* Global flag set */
1614 sender_host_address != NULL && /* Not local input */
1615 !sender_host_notsocket) /* Really is a socket */
1618 /* The variables $smtp_command and $smtp_command_argument point into the
1619 unmodified input buffer. A copy of the latter is taken for actual
1620 processing, so that it can be chopped up into separate parts if necessary,
1621 for example, when processing a MAIL command options such as SIZE that can
1622 follow the sender address. */
1624 smtp_cmd_argument = smtp_cmd_buffer + p->len;
1625 while (isspace(*smtp_cmd_argument)) smtp_cmd_argument++;
1626 Ustrcpy(smtp_data_buffer, smtp_cmd_argument);
1627 smtp_cmd_data = smtp_data_buffer;
1629 /* Count non-mail commands from those hosts that are controlled in this
1630 way. The default is all hosts. We don't waste effort checking the list
1631 until we get a non-mail command, but then cache the result to save checking
1632 again. If there's a DEFER while checking the host, assume it's in the list.
1634 Note that one instance of RSET, EHLO/HELO, and STARTTLS is allowed at the
1635 start of each incoming message by fiddling with the value in the table. */
1637 if (!p->is_mail_cmd)
1639 if (count_nonmail == TRUE_UNSET) count_nonmail =
1640 verify_check_host(&smtp_accept_max_nonmail_hosts) != FAIL;
1641 if (count_nonmail && ++nonmail_command_count > smtp_accept_max_nonmail)
1642 return TOO_MANY_NONMAIL_CMD;
1645 /* If there is data for a command that does not expect it, generate the
1648 return (p->has_arg || *smtp_cmd_data == 0)? p->cmd : BADARG_CMD;
1652 #ifdef SUPPORT_PROXY
1653 /* Only allow QUIT command if Proxy Protocol parsing failed */
1654 if (proxy_session && proxy_session_failed)
1655 return PROXY_FAIL_IGNORE_CMD;
1658 /* Enforce synchronization for unknown commands */
1660 if (smtp_inptr < smtp_inend && /* Outstanding input */
1661 check_sync && /* Local flag set */
1662 smtp_enforce_sync && /* Global flag set */
1663 sender_host_address != NULL && /* Not local input */
1664 !sender_host_notsocket) /* Really is a socket */
1672 /*************************************************
1673 * Forced closedown of call *
1674 *************************************************/
1676 /* This function is called from log.c when Exim is dying because of a serious
1677 disaster, and also from some other places. If an incoming non-batched SMTP
1678 channel is open, it swallows the rest of the incoming message if in the DATA
1679 phase, sends the reply string, and gives an error to all subsequent commands
1680 except QUIT. The existence of an SMTP call is detected by the non-NULLness of
1684 message SMTP reply string to send, excluding the code
1690 smtp_closedown(uschar *message)
1692 if (!smtp_in || smtp_batched_input) return;
1693 receive_swallow_smtp();
1694 smtp_printf("421 %s\r\n", FALSE, message);
1696 for (;;) switch(smtp_read_command(FALSE, GETC_BUFFER_UNLIMITED))
1702 smtp_printf("221 %s closing connection\r\n", FALSE, smtp_active_hostname);
1707 smtp_printf("250 Reset OK\r\n", FALSE);
1711 smtp_printf("421 %s\r\n", FALSE, message);
1719 /*************************************************
1720 * Set up connection info for logging *
1721 *************************************************/
1723 /* This function is called when logging information about an SMTP connection.
1724 It sets up appropriate source information, depending on the type of connection.
1725 If sender_fullhost is NULL, we are at a very early stage of the connection;
1726 just use the IP address.
1729 Returns: a string describing the connection
1733 smtp_get_connection_info(void)
1735 const uschar * hostname = sender_fullhost
1736 ? sender_fullhost : sender_host_address;
1739 return string_sprintf("SMTP connection from %s", hostname);
1741 if (sender_host_unknown || sender_host_notsocket)
1742 return string_sprintf("SMTP connection from %s", sender_ident);
1745 return string_sprintf("SMTP connection from %s (via inetd)", hostname);
1747 if (LOGGING(incoming_interface) && interface_address != NULL)
1748 return string_sprintf("SMTP connection from %s I=[%s]:%d", hostname,
1749 interface_address, interface_port);
1751 return string_sprintf("SMTP connection from %s", hostname);
1757 /* Append TLS-related information to a log line
1760 g String under construction: allocated string to extend, or NULL
1762 Returns: Allocated string or NULL
1765 s_tlslog(gstring * g)
1767 if (LOGGING(tls_cipher) && tls_in.cipher)
1768 g = string_append(g, 2, US" X=", tls_in.cipher);
1769 if (LOGGING(tls_certificate_verified) && tls_in.cipher)
1770 g = string_append(g, 2, US" CV=", tls_in.certificate_verified? "yes":"no");
1771 if (LOGGING(tls_peerdn) && tls_in.peerdn)
1772 g = string_append(g, 3, US" DN=\"", string_printing(tls_in.peerdn), US"\"");
1773 if (LOGGING(tls_sni) && tls_in.sni)
1774 g = string_append(g, 3, US" SNI=\"", string_printing(tls_in.sni), US"\"");
1779 /*************************************************
1780 * Log lack of MAIL if so configured *
1781 *************************************************/
1783 /* This function is called when an SMTP session ends. If the log selector
1784 smtp_no_mail is set, write a log line giving some details of what has happened
1785 in the SMTP session.
1792 smtp_log_no_mail(void)
1798 if (smtp_mailcmd_count > 0 || !LOGGING(smtp_no_mail))
1801 if (sender_host_authenticated)
1803 g = string_append(g, 2, US" A=", sender_host_authenticated);
1804 if (authenticated_id) g = string_append(g, 2, US":", authenticated_id);
1811 sep = smtp_connection_had[SMTP_HBUFF_SIZE-1] != SCH_NONE ? US" C=..." : US" C=";
1813 for (i = smtp_ch_index; i < SMTP_HBUFF_SIZE; i++)
1814 if (smtp_connection_had[i] != SCH_NONE)
1816 g = string_append(g, 2, sep, smtp_names[smtp_connection_had[i]]);
1820 for (i = 0; i < smtp_ch_index; i++)
1822 g = string_append(g, 2, sep, smtp_names[smtp_connection_had[i]]);
1826 if (!(s = string_from_gstring(g))) s = US"";
1828 log_write(0, LOG_MAIN, "no MAIL in %sSMTP connection from %s D=%s%s",
1829 tcp_in_fastopen ? US"TFO " : US"",
1830 host_and_ident(FALSE), string_timesince(&smtp_connection_start), s);
1834 /* Return list of recent smtp commands */
1840 gstring * list = NULL;
1843 for (i = smtp_ch_index; i < SMTP_HBUFF_SIZE; i++)
1844 if (smtp_connection_had[i] != SCH_NONE)
1845 list = string_append_listele(list, ',', smtp_names[smtp_connection_had[i]]);
1847 for (i = 0; i < smtp_ch_index; i++)
1848 list = string_append_listele(list, ',', smtp_names[smtp_connection_had[i]]);
1850 s = string_from_gstring(list);
1851 return s ? s : US"";
1857 /*************************************************
1858 * Check HELO line and set sender_helo_name *
1859 *************************************************/
1861 /* Check the format of a HELO line. The data for HELO/EHLO is supposed to be
1862 the domain name of the sending host, or an ip literal in square brackets. The
1863 argument is placed in sender_helo_name, which is in malloc store, because it
1864 must persist over multiple incoming messages. If helo_accept_junk is set, this
1865 host is permitted to send any old junk (needed for some broken hosts).
1866 Otherwise, helo_allow_chars can be used for rogue characters in general
1867 (typically people want to let in underscores).
1870 s the data portion of the line (already past any white space)
1872 Returns: TRUE or FALSE
1876 check_helo(uschar *s)
1879 uschar *end = s + Ustrlen(s);
1880 BOOL yield = helo_accept_junk;
1882 /* Discard any previous helo name */
1884 if (sender_helo_name)
1886 store_free(sender_helo_name);
1887 sender_helo_name = NULL;
1890 /* Skip tests if junk is permitted. */
1894 /* Allow the new standard form for IPv6 address literals, namely,
1895 [IPv6:....], and because someone is bound to use it, allow an equivalent
1896 IPv4 form. Allow plain addresses as well. */
1903 if (strncmpic(s, US"[IPv6:", 6) == 0)
1904 yield = (string_is_ip_address(s+6, NULL) == 6);
1905 else if (strncmpic(s, US"[IPv4:", 6) == 0)
1906 yield = (string_is_ip_address(s+6, NULL) == 4);
1908 yield = (string_is_ip_address(s+1, NULL) != 0);
1913 /* Non-literals must be alpha, dot, hyphen, plus any non-valid chars
1914 that have been configured (usually underscore - sigh). */
1917 for (yield = TRUE; *s; s++)
1918 if (!isalnum(*s) && *s != '.' && *s != '-' &&
1919 Ustrchr(helo_allow_chars, *s) == NULL)
1925 /* Save argument if OK */
1927 if (yield) sender_helo_name = string_copy_malloc(start);
1935 /*************************************************
1936 * Extract SMTP command option *
1937 *************************************************/
1939 /* This function picks the next option setting off the end of smtp_cmd_data. It
1940 is called for MAIL FROM and RCPT TO commands, to pick off the optional ESMTP
1941 things that can appear there.
1944 name point this at the name
1945 value point this at the data string
1947 Returns: TRUE if found an option
1951 extract_option(uschar **name, uschar **value)
1954 uschar *v = smtp_cmd_data + Ustrlen(smtp_cmd_data) - 1;
1955 while (isspace(*v)) v--;
1957 while (v > smtp_cmd_data && *v != '=' && !isspace(*v))
1959 /* Take care to not stop at a space embedded in a quoted local-part */
1961 if (*v == '"') do v--; while (*v != '"' && v > smtp_cmd_data+1);
1968 while(isalpha(n[-1])) n--;
1969 /* RFC says SP, but TAB seen in wild and other major MTAs accept it */
1970 if (!isspace(n[-1])) return FALSE;
1976 if (v == smtp_cmd_data) return FALSE;
1988 /*************************************************
1989 * Reset for new message *
1990 *************************************************/
1992 /* This function is called whenever the SMTP session is reset from
1993 within either of the setup functions; also from the daemon loop.
1995 Argument: the stacking pool storage reset point
2000 smtp_reset(void *reset_point)
2002 recipients_list = NULL;
2003 rcpt_count = rcpt_defer_count = rcpt_fail_count =
2004 raw_recipients_count = recipients_count = recipients_list_max = 0;
2005 message_linecount = 0;
2007 acl_added_headers = NULL;
2008 acl_removed_headers = NULL;
2009 queue_only_policy = FALSE;
2010 rcpt_smtp_response = NULL;
2011 rcpt_smtp_response_same = TRUE;
2012 rcpt_in_progress = FALSE;
2013 deliver_freeze = FALSE; /* Can be set by ACL */
2014 freeze_tell = freeze_tell_config; /* Can be set by ACL */
2015 fake_response = OK; /* Can be set by ACL */
2016 #ifdef WITH_CONTENT_SCAN
2017 no_mbox_unspool = FALSE; /* Can be set by ACL */
2019 submission_mode = FALSE; /* Can be set by ACL */
2020 suppress_local_fixups = suppress_local_fixups_default; /* Can be set by ACL */
2021 active_local_from_check = local_from_check; /* Can be set by ACL */
2022 active_local_sender_retain = local_sender_retain; /* Can be set by ACL */
2023 sending_ip_address = NULL;
2024 return_path = sender_address = NULL;
2025 sender_data = NULL; /* Can be set by ACL */
2026 deliver_localpart_orig = NULL;
2027 deliver_domain_orig = NULL;
2028 callout_address = NULL;
2029 submission_name = NULL; /* Can be set by ACL */
2030 raw_sender = NULL; /* After SMTP rewrite, before qualifying */
2031 sender_address_unrewritten = NULL; /* Set only after verify rewrite */
2032 sender_verified_list = NULL; /* No senders verified */
2033 memset(sender_address_cache, 0, sizeof(sender_address_cache));
2034 memset(sender_domain_cache, 0, sizeof(sender_domain_cache));
2036 authenticated_sender = NULL;
2037 #ifdef EXPERIMENTAL_BRIGHTMAIL
2039 bmi_verdicts = NULL;
2041 dnslist_domain = dnslist_matched = NULL;
2042 #ifndef DISABLE_DKIM
2043 dkim_cur_signer = dkim_signers =
2044 dkim_signing_domain = dkim_signing_selector = dkim_signatures = NULL;
2045 dkim_disable_verify = dkim_collect_input = FALSE;
2047 #ifdef EXPERIMENTAL_DMARC
2048 dmarc_has_been_checked = dmarc_disable_verify = dmarc_enable_forensic = FALSE;
2049 dmarc_ar_header = dmarc_domain_policy = dmarc_forensic_sender =
2050 dmarc_history_file = dmarc_status = dmarc_status_text = dmarc_tld_file =
2051 dmarc_used_domain = NULL;
2055 deliver_host = deliver_host_address = NULL; /* Can be set by ACL */
2056 #ifndef DISABLE_PRDR
2057 prdr_requested = FALSE;
2060 spf_header_comment = spf_received = spf_result = spf_smtp_comment = NULL;
2062 #ifdef EXPERIMENTAL_ARC
2063 arc_state = arc_state_reason = NULL;
2066 message_smtputf8 = FALSE;
2068 body_linecount = body_zerocount = 0;
2070 sender_rate = sender_rate_limit = sender_rate_period = NULL;
2071 ratelimiters_mail = NULL; /* Updated by ratelimit ACL condition */
2072 /* Note that ratelimiters_conn persists across resets. */
2074 /* Reset message ACL variables */
2078 /* The message body variables use malloc store. They may be set if this is
2079 not the first message in an SMTP session and the previous message caused them
2080 to be referenced in an ACL. */
2084 store_free(message_body);
2085 message_body = NULL;
2088 if (message_body_end)
2090 store_free(message_body_end);
2091 message_body_end = NULL;
2094 /* Warning log messages are also saved in malloc store. They are saved to avoid
2095 repetition in the same message, but it seems right to repeat them for different
2098 while (acl_warn_logged)
2100 string_item *this = acl_warn_logged;
2101 acl_warn_logged = acl_warn_logged->next;
2104 store_reset(reset_point);
2111 /*************************************************
2112 * Initialize for incoming batched SMTP message *
2113 *************************************************/
2115 /* This function is called from smtp_setup_msg() in the case when
2116 smtp_batched_input is true. This happens when -bS is used to pass a whole batch
2117 of messages in one file with SMTP commands between them. All errors must be
2118 reported by sending a message, and only MAIL FROM, RCPT TO, and DATA are
2119 relevant. After an error on a sender, or an invalid recipient, the remainder
2120 of the message is skipped. The value of received_protocol is already set.
2123 Returns: > 0 message successfully started (reached DATA)
2124 = 0 QUIT read or end of file reached
2125 < 0 should not occur
2129 smtp_setup_batch_msg(void)
2132 void *reset_point = store_get(0);
2134 /* Save the line count at the start of each transaction - single commands
2135 like HELO and RSET count as whole transactions. */
2137 bsmtp_transaction_linecount = receive_linecount;
2139 if ((receive_feof)()) return 0; /* Treat EOF as QUIT */
2141 cancel_cutthrough_connection(TRUE, US"smtp_setup_batch_msg");
2142 smtp_reset(reset_point); /* Reset for start of message */
2144 /* Deal with SMTP commands. This loop is exited by setting done to a POSITIVE
2145 value. The values are 2 larger than the required yield of the function. */
2150 uschar *recipient = NULL;
2151 int start, end, sender_domain, recipient_domain;
2153 switch(smtp_read_command(FALSE, GETC_BUFFER_UNLIMITED))
2155 /* The HELO/EHLO commands set sender_address_helo if they have
2156 valid data; otherwise they are ignored, except that they do
2157 a reset of the state. */
2162 check_helo(smtp_cmd_data);
2166 cancel_cutthrough_connection(TRUE, US"RSET received");
2167 smtp_reset(reset_point);
2168 bsmtp_transaction_linecount = receive_linecount;
2172 /* The MAIL FROM command requires an address as an operand. All we
2173 do here is to parse it for syntactic correctness. The form "<>" is
2174 a special case which converts into an empty string. The start/end
2175 pointers in the original are not used further for this address, as
2176 it is the canonical extracted address which is all that is kept. */
2179 smtp_mailcmd_count++; /* Count for no-mail log */
2180 if (sender_address != NULL)
2181 /* The function moan_smtp_batch() does not return. */
2182 moan_smtp_batch(smtp_cmd_buffer, "503 Sender already given");
2184 if (smtp_cmd_data[0] == 0)
2185 /* The function moan_smtp_batch() does not return. */
2186 moan_smtp_batch(smtp_cmd_buffer, "501 MAIL FROM must have an address operand");
2188 /* Reset to start of message */
2190 cancel_cutthrough_connection(TRUE, US"MAIL received");
2191 smtp_reset(reset_point);
2193 /* Apply SMTP rewrite */
2195 raw_sender = ((rewrite_existflags & rewrite_smtp) != 0)?
2196 rewrite_one(smtp_cmd_data, rewrite_smtp|rewrite_smtp_sender, NULL, FALSE,
2197 US"", global_rewrite_rules) : smtp_cmd_data;
2199 /* Extract the address; the TRUE flag allows <> as valid */
2202 parse_extract_address(raw_sender, &errmess, &start, &end, &sender_domain,
2206 /* The function moan_smtp_batch() does not return. */
2207 moan_smtp_batch(smtp_cmd_buffer, "501 %s", errmess);
2209 sender_address = string_copy(raw_sender);
2211 /* Qualify unqualified sender addresses if permitted to do so. */
2214 && sender_address[0] != 0 && sender_address[0] != '@')
2215 if (allow_unqualified_sender)
2217 sender_address = rewrite_address_qualify(sender_address, FALSE);
2218 DEBUG(D_receive) debug_printf("unqualified address %s accepted "
2219 "and rewritten\n", raw_sender);
2221 /* The function moan_smtp_batch() does not return. */
2223 moan_smtp_batch(smtp_cmd_buffer, "501 sender address must contain "
2228 /* The RCPT TO command requires an address as an operand. All we do
2229 here is to parse it for syntactic correctness. There may be any number
2230 of RCPT TO commands, specifying multiple senders. We build them all into
2231 a data structure that is in argc/argv format. The start/end values
2232 given by parse_extract_address are not used, as we keep only the
2233 extracted address. */
2236 if (!sender_address)
2237 /* The function moan_smtp_batch() does not return. */
2238 moan_smtp_batch(smtp_cmd_buffer, "503 No sender yet given");
2240 if (smtp_cmd_data[0] == 0)
2241 /* The function moan_smtp_batch() does not return. */
2242 moan_smtp_batch(smtp_cmd_buffer,
2243 "501 RCPT TO must have an address operand");
2245 /* Check maximum number allowed */
2247 if (recipients_max > 0 && recipients_count + 1 > recipients_max)
2248 /* The function moan_smtp_batch() does not return. */
2249 moan_smtp_batch(smtp_cmd_buffer, "%s too many recipients",
2250 recipients_max_reject? "552": "452");
2252 /* Apply SMTP rewrite, then extract address. Don't allow "<>" as a
2253 recipient address */
2255 recipient = rewrite_existflags & rewrite_smtp
2256 ? rewrite_one(smtp_cmd_data, rewrite_smtp, NULL, FALSE, US"",
2257 global_rewrite_rules)
2260 recipient = parse_extract_address(recipient, &errmess, &start, &end,
2261 &recipient_domain, FALSE);
2264 /* The function moan_smtp_batch() does not return. */
2265 moan_smtp_batch(smtp_cmd_buffer, "501 %s", errmess);
2267 /* If the recipient address is unqualified, qualify it if permitted. Then
2268 add it to the list of recipients. */
2270 if (!recipient_domain)
2271 if (allow_unqualified_recipient)
2273 DEBUG(D_receive) debug_printf("unqualified address %s accepted\n",
2275 recipient = rewrite_address_qualify(recipient, TRUE);
2277 /* The function moan_smtp_batch() does not return. */
2279 moan_smtp_batch(smtp_cmd_buffer,
2280 "501 recipient address must contain a domain");
2282 receive_add_recipient(recipient, -1);
2286 /* The DATA command is legal only if it follows successful MAIL FROM
2287 and RCPT TO commands. This function is complete when a valid DATA
2288 command is encountered. */
2291 if (!sender_address || recipients_count <= 0)
2292 /* The function moan_smtp_batch() does not return. */
2293 if (!sender_address)
2294 moan_smtp_batch(smtp_cmd_buffer,
2295 "503 MAIL FROM:<sender> command must precede DATA");
2297 moan_smtp_batch(smtp_cmd_buffer,
2298 "503 RCPT TO:<recipient> must precede DATA");
2301 done = 3; /* DATA successfully achieved */
2302 message_ended = END_NOTENDED; /* Indicate in middle of message */
2307 /* The VRFY, EXPN, HELP, ETRN, and NOOP commands are ignored. */
2314 bsmtp_transaction_linecount = receive_linecount;
2325 /* The function moan_smtp_batch() does not return. */
2326 moan_smtp_batch(smtp_cmd_buffer, "501 Unexpected argument data");
2331 /* The function moan_smtp_batch() does not return. */
2332 moan_smtp_batch(smtp_cmd_buffer, "501 Unexpected NULL in SMTP command");
2337 /* The function moan_smtp_batch() does not return. */
2338 moan_smtp_batch(smtp_cmd_buffer, "500 Command unrecognized");
2343 return done - 2; /* Convert yield values */
2350 smtp_log_tls_fail(uschar * errstr)
2352 uschar * conn_info = smtp_get_connection_info();
2354 if (Ustrncmp(conn_info, US"SMTP ", 5) == 0) conn_info += 5;
2355 /* I'd like to get separated H= here, but too hard for now */
2357 log_write(0, LOG_MAIN, "TLS error on %s %s", conn_info, errstr);
2369 struct tcp_info tinfo;
2370 socklen_t len = sizeof(tinfo);
2372 if ( getsockopt(fileno(smtp_out), IPPROTO_TCP, TCP_INFO, &tinfo, &len) == 0
2373 && tinfo.tcpi_state == TCP_SYN_RECV
2376 DEBUG(D_receive) debug_printf("TCP_FASTOPEN mode connection (state TCP_SYN_RECV)\n");
2377 tcp_in_fastopen = TRUE;
2384 /*************************************************
2385 * Start an SMTP session *
2386 *************************************************/
2388 /* This function is called at the start of an SMTP session. Thereafter,
2389 smtp_setup_msg() is called to initiate each separate message. This
2390 function does host-specific testing, and outputs the banner line.
2393 Returns: FALSE if the session can not continue; something has
2394 gone wrong, or the connection to the host is blocked
2398 smtp_start_session(void)
2401 uschar *user_msg, *log_msg;
2406 gettimeofday(&smtp_connection_start, NULL);
2407 for (smtp_ch_index = 0; smtp_ch_index < SMTP_HBUFF_SIZE; smtp_ch_index++)
2408 smtp_connection_had[smtp_ch_index] = SCH_NONE;
2411 /* Default values for certain variables */
2413 helo_seen = esmtp = helo_accept_junk = FALSE;
2414 smtp_mailcmd_count = 0;
2415 count_nonmail = TRUE_UNSET;
2416 synprot_error_count = unknown_command_count = nonmail_command_count = 0;
2417 smtp_delay_mail = smtp_rlm_base;
2418 auth_advertised = FALSE;
2419 pipelining_advertised = FALSE;
2420 pipelining_enable = TRUE;
2421 sync_cmd_limit = NON_SYNC_CMD_NON_PIPELINING;
2422 smtp_exit_function_called = FALSE; /* For avoiding loop in not-quit exit */
2424 /* If receiving by -bs from a trusted user, or testing with -bh, we allow
2425 authentication settings from -oMaa to remain in force. */
2427 if (!host_checking && !sender_host_notsocket)
2428 sender_host_auth_pubname = sender_host_authenticated = NULL;
2429 authenticated_by = NULL;
2432 tls_in.cipher = tls_in.peerdn = NULL;
2433 tls_in.ourcert = tls_in.peercert = NULL;
2435 tls_in.ocsp = OCSP_NOT_REQ;
2436 tls_advertised = FALSE;
2438 dsn_advertised = FALSE;
2440 smtputf8_advertised = FALSE;
2443 /* Reset ACL connection variables */
2447 /* Allow for trailing 0 in the command and data buffers. */
2449 if (!(smtp_cmd_buffer = US malloc(2*SMTP_CMD_BUFFER_SIZE + 2)))
2450 log_write(0, LOG_MAIN|LOG_PANIC_DIE,
2451 "malloc() failed for SMTP command buffer");
2453 smtp_cmd_buffer[0] = 0;
2454 smtp_data_buffer = smtp_cmd_buffer + SMTP_CMD_BUFFER_SIZE + 1;
2456 /* For batched input, the protocol setting can be overridden from the
2457 command line by a trusted caller. */
2459 if (smtp_batched_input)
2461 if (!received_protocol) received_protocol = US"local-bsmtp";
2464 /* For non-batched SMTP input, the protocol setting is forced here. It will be
2465 reset later if any of EHLO/AUTH/STARTTLS are received. */
2469 (sender_host_address ? protocols : protocols_local) [pnormal];
2471 /* Set up the buffer for inputting using direct read() calls, and arrange to
2472 call the local functions instead of the standard C ones. */
2474 if (!(smtp_inbuffer = US malloc(IN_BUFFER_SIZE)))
2475 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "malloc() failed for SMTP input buffer");
2477 receive_getc = smtp_getc;
2478 receive_getbuf = smtp_getbuf;
2479 receive_get_cache = smtp_get_cache;
2480 receive_ungetc = smtp_ungetc;
2481 receive_feof = smtp_feof;
2482 receive_ferror = smtp_ferror;
2483 receive_smtp_buffered = smtp_buffered;
2484 smtp_inptr = smtp_inend = smtp_inbuffer;
2485 smtp_had_eof = smtp_had_error = 0;
2487 /* Set up the message size limit; this may be host-specific */
2489 thismessage_size_limit = expand_string_integer(message_size_limit, TRUE);
2490 if (expand_string_message)
2492 if (thismessage_size_limit == -1)
2493 log_write(0, LOG_MAIN|LOG_PANIC, "unable to expand message_size_limit: "
2494 "%s", expand_string_message);
2496 log_write(0, LOG_MAIN|LOG_PANIC, "invalid message_size_limit: "
2497 "%s", expand_string_message);
2498 smtp_closedown(US"Temporary local problem - please try later");
2502 /* When a message is input locally via the -bs or -bS options, sender_host_
2503 unknown is set unless -oMa was used to force an IP address, in which case it
2504 is checked like a real remote connection. When -bs is used from inetd, this
2505 flag is not set, causing the sending host to be checked. The code that deals
2506 with IP source routing (if configured) is never required for -bs or -bS and
2507 the flag sender_host_notsocket is used to suppress it.
2509 If smtp_accept_max and smtp_accept_reserve are set, keep some connections in
2510 reserve for certain hosts and/or networks. */
2512 if (!sender_host_unknown)
2515 BOOL reserved_host = FALSE;
2517 /* Look up IP options (source routing info) on the socket if this is not an
2518 -oMa "host", and if any are found, log them and drop the connection.
2520 Linux (and others now, see below) is different to everyone else, so there
2521 has to be some conditional compilation here. Versions of Linux before 2.1.15
2522 used a structure whose name was "options". Somebody finally realized that
2523 this name was silly, and it got changed to "ip_options". I use the
2524 newer name here, but there is a fudge in the script that sets up os.h
2525 to define a macro in older Linux systems.
2527 Sigh. Linux is a fast-moving target. Another generation of Linux uses
2528 glibc 2, which has chosen ip_opts for the structure name. This is now
2529 really a glibc thing rather than a Linux thing, so the condition name
2530 has been changed to reflect this. It is relevant also to GNU/Hurd.
2532 Mac OS 10.x (Darwin) is like the later glibc versions, but without the
2533 setting of the __GLIBC__ macro, so we can't detect it automatically. There's
2534 a special macro defined in the os.h file.
2536 Some DGUX versions on older hardware appear not to support IP options at
2537 all, so there is now a general macro which can be set to cut out this
2540 How to do this properly in IPv6 is not yet known. */
2542 #if !HAVE_IPV6 && !defined(NO_IP_OPTIONS)
2544 #ifdef GLIBC_IP_OPTIONS
2545 #if (!defined __GLIBC__) || (__GLIBC__ < 2)
2550 #elif defined DARWIN_IP_OPTIONS
2556 if (!host_checking && !sender_host_notsocket)
2559 EXIM_SOCKLEN_T optlen = sizeof(struct ip_options) + MAX_IPOPTLEN;
2560 struct ip_options *ipopt = store_get(optlen);
2562 struct ip_opts ipoptblock;
2563 struct ip_opts *ipopt = &ipoptblock;
2564 EXIM_SOCKLEN_T optlen = sizeof(ipoptblock);
2566 struct ipoption ipoptblock;
2567 struct ipoption *ipopt = &ipoptblock;
2568 EXIM_SOCKLEN_T optlen = sizeof(ipoptblock);
2571 /* Occasional genuine failures of getsockopt() have been seen - for
2572 example, "reset by peer". Therefore, just log and give up on this
2573 call, unless the error is ENOPROTOOPT. This error is given by systems
2574 that have the interfaces but not the mechanism - e.g. GNU/Hurd at the time
2575 of writing. So for that error, carry on - we just can't do an IP options
2578 DEBUG(D_receive) debug_printf("checking for IP options\n");
2580 if (getsockopt(fileno(smtp_out), IPPROTO_IP, IP_OPTIONS, US (ipopt),
2583 if (errno != ENOPROTOOPT)
2585 log_write(0, LOG_MAIN, "getsockopt() failed from %s: %s",
2586 host_and_ident(FALSE), strerror(errno));
2587 smtp_printf("451 SMTP service not available\r\n", FALSE);
2592 /* Deal with any IP options that are set. On the systems I have looked at,
2593 the value of MAX_IPOPTLEN has been 40, meaning that there should never be
2594 more logging data than will fit in big_buffer. Nevertheless, after somebody
2595 questioned this code, I've added in some paranoid checking. */
2597 else if (optlen > 0)
2599 uschar *p = big_buffer;
2600 uschar *pend = big_buffer + big_buffer_size;
2601 uschar *opt, *adptr;
2603 struct in_addr addr;
2606 uschar *optstart = US (ipopt->__data);
2608 uschar *optstart = US (ipopt->ip_opts);
2610 uschar *optstart = US (ipopt->ipopt_list);
2613 DEBUG(D_receive) debug_printf("IP options exist\n");
2615 Ustrcpy(p, "IP options on incoming call:");
2618 for (opt = optstart; opt != NULL &&
2619 opt < US (ipopt) + optlen;)
2633 if (!string_format(p, pend-p, " %s [@%s",
2634 (*opt == IPOPT_SSRR)? "SSRR" : "LSRR",
2636 inet_ntoa(*((struct in_addr *)(&(ipopt->faddr))))))
2638 inet_ntoa(ipopt->ip_dst)))
2640 inet_ntoa(ipopt->ipopt_dst)))
2648 optcount = (opt[1] - 3) / sizeof(struct in_addr);
2650 while (optcount-- > 0)
2652 memcpy(&addr, adptr, sizeof(addr));
2653 if (!string_format(p, pend - p - 1, "%s%s",
2654 (optcount == 0)? ":" : "@", inet_ntoa(addr)))
2660 adptr += sizeof(struct in_addr);
2669 if (pend - p < 4 + 3*opt[1]) { opt = NULL; break; }
2672 for (i = 0; i < opt[1]; i++)
2673 p += sprintf(CS p, "%2.2x ", opt[i]);
2682 log_write(0, LOG_MAIN, "%s", big_buffer);
2684 /* Refuse any call with IP options. This is what tcpwrappers 7.5 does. */
2686 log_write(0, LOG_MAIN|LOG_REJECT,
2687 "connection from %s refused (IP options)", host_and_ident(FALSE));
2689 smtp_printf("554 SMTP service not available\r\n", FALSE);
2693 /* Length of options = 0 => there are no options */
2695 else DEBUG(D_receive) debug_printf("no IP options found\n");
2697 #endif /* HAVE_IPV6 && !defined(NO_IP_OPTIONS) */
2699 /* Set keep-alive in socket options. The option is on by default. This
2700 setting is an attempt to get rid of some hanging connections that stick in
2701 read() when the remote end (usually a dialup) goes away. */
2703 if (smtp_accept_keepalive && !sender_host_notsocket)
2704 ip_keepalive(fileno(smtp_out), sender_host_address, FALSE);
2706 /* If the current host matches host_lookup, set the name by doing a
2707 reverse lookup. On failure, sender_host_name will be NULL and
2708 host_lookup_failed will be TRUE. This may or may not be serious - optional
2711 if (verify_check_host(&host_lookup) == OK)
2713 (void)host_name_lookup();
2714 host_build_sender_fullhost();
2717 /* Delay this until we have the full name, if it is looked up. */
2719 set_process_info("handling incoming connection from %s",
2720 host_and_ident(FALSE));
2722 /* Expand smtp_receive_timeout, if needed */
2724 if (smtp_receive_timeout_s)
2727 if ( !(exp = expand_string(smtp_receive_timeout_s))
2729 || (smtp_receive_timeout = readconf_readtime(exp, 0, FALSE)) < 0
2731 log_write(0, LOG_MAIN|LOG_PANIC,
2732 "bad value for smtp_receive_timeout: '%s'", exp ? exp : US"");
2735 /* Test for explicit connection rejection */
2737 if (verify_check_host(&host_reject_connection) == OK)
2739 log_write(L_connection_reject, LOG_MAIN|LOG_REJECT, "refused connection "
2740 "from %s (host_reject_connection)", host_and_ident(FALSE));
2741 smtp_printf("554 SMTP service not available\r\n", FALSE);
2745 /* Test with TCP Wrappers if so configured. There is a problem in that
2746 hosts_ctl() returns 0 (deny) under a number of system failure circumstances,
2747 such as disks dying. In these cases, it is desirable to reject with a 4xx
2748 error instead of a 5xx error. There isn't a "right" way to detect such
2749 problems. The following kludge is used: errno is zeroed before calling
2750 hosts_ctl(). If the result is "reject", a 5xx error is given only if the
2751 value of errno is 0 or ENOENT (which happens if /etc/hosts.{allow,deny} does
2754 #ifdef USE_TCP_WRAPPERS
2756 if (!(tcp_wrappers_name = expand_string(tcp_wrappers_daemon_name)))
2757 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "Expansion of \"%s\" "
2758 "(tcp_wrappers_name) failed: %s", string_printing(tcp_wrappers_name),
2759 expand_string_message);
2761 if (!hosts_ctl(tcp_wrappers_name,
2762 sender_host_name ? CS sender_host_name : STRING_UNKNOWN,
2763 sender_host_address ? CS sender_host_address : STRING_UNKNOWN,
2764 sender_ident ? CS sender_ident : STRING_UNKNOWN))
2766 if (errno == 0 || errno == ENOENT)
2768 HDEBUG(D_receive) debug_printf("tcp wrappers rejection\n");
2769 log_write(L_connection_reject,
2770 LOG_MAIN|LOG_REJECT, "refused connection from %s "
2771 "(tcp wrappers)", host_and_ident(FALSE));
2772 smtp_printf("554 SMTP service not available\r\n", FALSE);
2776 int save_errno = errno;
2777 HDEBUG(D_receive) debug_printf("tcp wrappers rejected with unexpected "
2778 "errno value %d\n", save_errno);
2779 log_write(L_connection_reject,
2780 LOG_MAIN|LOG_REJECT, "temporarily refused connection from %s "
2781 "(tcp wrappers errno=%d)", host_and_ident(FALSE), save_errno);
2782 smtp_printf("451 Temporary local problem - please try later\r\n", FALSE);
2788 /* Check for reserved slots. The value of smtp_accept_count has already been
2789 incremented to include this process. */
2791 if (smtp_accept_max > 0 &&
2792 smtp_accept_count > smtp_accept_max - smtp_accept_reserve)
2794 if ((rc = verify_check_host(&smtp_reserve_hosts)) != OK)
2796 log_write(L_connection_reject,
2797 LOG_MAIN, "temporarily refused connection from %s: not in "
2798 "reserve list: connected=%d max=%d reserve=%d%s",
2799 host_and_ident(FALSE), smtp_accept_count - 1, smtp_accept_max,
2800 smtp_accept_reserve, (rc == DEFER)? " (lookup deferred)" : "");
2801 smtp_printf("421 %s: Too many concurrent SMTP connections; "
2802 "please try again later\r\n", FALSE, smtp_active_hostname);
2805 reserved_host = TRUE;
2808 /* If a load level above which only messages from reserved hosts are
2809 accepted is set, check the load. For incoming calls via the daemon, the
2810 check is done in the superior process if there are no reserved hosts, to
2811 save a fork. In all cases, the load average will already be available
2812 in a global variable at this point. */
2814 if (smtp_load_reserve >= 0 &&
2815 load_average > smtp_load_reserve &&
2817 verify_check_host(&smtp_reserve_hosts) != OK)
2819 log_write(L_connection_reject,
2820 LOG_MAIN, "temporarily refused connection from %s: not in "
2821 "reserve list and load average = %.2f", host_and_ident(FALSE),
2822 (double)load_average/1000.0);
2823 smtp_printf("421 %s: Too much load; please try again later\r\n", FALSE,
2824 smtp_active_hostname);
2828 /* Determine whether unqualified senders or recipients are permitted
2829 for this host. Unfortunately, we have to do this every time, in order to
2830 set the flags so that they can be inspected when considering qualifying
2831 addresses in the headers. For a site that permits no qualification, this
2832 won't take long, however. */
2834 allow_unqualified_sender =
2835 verify_check_host(&sender_unqualified_hosts) == OK;
2837 allow_unqualified_recipient =
2838 verify_check_host(&recipient_unqualified_hosts) == OK;
2840 /* Determine whether HELO/EHLO is required for this host. The requirement
2841 can be hard or soft. */
2843 helo_required = verify_check_host(&helo_verify_hosts) == OK;
2845 helo_verify = verify_check_host(&helo_try_verify_hosts) == OK;
2847 /* Determine whether this hosts is permitted to send syntactic junk
2848 after a HELO or EHLO command. */
2850 helo_accept_junk = verify_check_host(&helo_accept_junk_hosts) == OK;
2853 /* For batch SMTP input we are now done. */
2855 if (smtp_batched_input) return TRUE;
2857 /* If valid Proxy Protocol source is connecting, set up session.
2858 * Failure will not allow any SMTP function other than QUIT. */
2860 #ifdef SUPPORT_PROXY
2861 proxy_session = FALSE;
2862 proxy_session_failed = FALSE;
2863 if (check_proxy_protocol_host())
2864 setup_proxy_protocol_host();
2867 /* Start up TLS if tls_on_connect is set. This is for supporting the legacy
2868 smtps port for use with older style SSL MTAs. */
2871 if (tls_in.on_connect)
2873 if (tls_server_start(tls_require_ciphers, &user_msg) != OK)
2874 return smtp_log_tls_fail(user_msg);
2875 cmd_list[CMD_LIST_TLS_AUTH].is_mail_cmd = TRUE;
2879 /* Run the connect ACL if it exists */
2882 if (acl_smtp_connect)
2885 if ((rc = acl_check(ACL_WHERE_CONNECT, NULL, acl_smtp_connect, &user_msg,
2888 (void) smtp_handle_acl_fail(ACL_WHERE_CONNECT, rc, user_msg, log_msg);
2893 /* Output the initial message for a two-way SMTP connection. It may contain
2894 newlines, which then cause a multi-line response to be given. */
2896 code = US"220"; /* Default status code */
2897 esc = US""; /* Default extended status code */
2898 esclen = 0; /* Length of esc */
2902 if (!(s = expand_string(smtp_banner)))
2903 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "Expansion of \"%s\" (smtp_banner) "
2904 "failed: %s", smtp_banner, expand_string_message);
2910 smtp_message_code(&code, &codelen, &s, NULL, TRUE);
2914 esclen = codelen - 4;
2918 /* Remove any terminating newlines; might as well remove trailing space too */
2921 while (p > s && isspace(p[-1])) p--;
2924 /* It seems that CC:Mail is braindead, and assumes that the greeting message
2925 is all contained in a single IP packet. The original code wrote out the
2926 greeting using several calls to fprint/fputc, and on busy servers this could
2927 cause it to be split over more than one packet - which caused CC:Mail to fall
2928 over when it got the second part of the greeting after sending its first
2929 command. Sigh. To try to avoid this, build the complete greeting message
2930 first, and output it in one fell swoop. This gives a better chance of it
2931 ending up as a single packet. */
2933 ss = string_get(256);
2936 do /* At least once, in case we have an empty string */
2939 uschar *linebreak = Ustrchr(p, '\n');
2940 ss = string_catn(ss, code, 3);
2944 ss = string_catn(ss, US" ", 1);
2948 len = linebreak - p;
2949 ss = string_catn(ss, US"-", 1);
2951 ss = string_catn(ss, esc, esclen);
2952 ss = string_catn(ss, p, len);
2953 ss = string_catn(ss, US"\r\n", 2);
2959 /* Before we write the banner, check that there is no input pending, unless
2960 this synchronisation check is disabled. */
2964 unsigned n = smtp_inend - smtp_inptr;
2967 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP protocol "
2968 "synchronization error (input sent without waiting for greeting): "
2969 "rejected connection from %s input=\"%s\"", host_and_ident(TRUE),
2970 string_printing(string_copyn(smtp_inptr, n)));
2971 smtp_printf("554 SMTP synchronization error\r\n", FALSE);
2975 /* Now output the banner */
2977 smtp_printf("%s", FALSE, string_from_gstring(ss));
2979 /* Attempt to see if we sent the banner before the last ACK of the 3-way
2980 handshake arrived. If so we must have managed a TFO. */
2993 /*************************************************
2994 * Handle SMTP syntax and protocol errors *
2995 *************************************************/
2997 /* Write to the log for SMTP syntax errors in incoming commands, if configured
2998 to do so. Then transmit the error response. The return value depends on the
2999 number of syntax and protocol errors in this SMTP session.
3002 type error type, given as a log flag bit
3003 code response code; <= 0 means don't send a response
3004 data data to reflect in the response (can be NULL)
3005 errmess the error message
3007 Returns: -1 limit of syntax/protocol errors NOT exceeded
3008 +1 limit of syntax/protocol errors IS exceeded
3010 These values fit in with the values of the "done" variable in the main
3011 processing loop in smtp_setup_msg(). */
3014 synprot_error(int type, int code, uschar *data, uschar *errmess)
3018 log_write(type, LOG_MAIN, "SMTP %s error in \"%s\" %s %s",
3019 (type == L_smtp_syntax_error)? "syntax" : "protocol",
3020 string_printing(smtp_cmd_buffer), host_and_ident(TRUE), errmess);
3022 if (++synprot_error_count > smtp_max_synprot_errors)
3025 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
3026 "syntax or protocol errors (last command was \"%s\")",
3027 host_and_ident(FALSE), string_printing(smtp_cmd_buffer));
3032 smtp_printf("%d%c%s%s%s\r\n", FALSE, code, yield == 1 ? '-' : ' ',
3033 data ? data : US"", data ? US": " : US"", errmess);
3035 smtp_printf("%d Too many syntax or protocol errors\r\n", FALSE, code);
3044 /*************************************************
3045 * Send SMTP response, possibly multiline *
3046 *************************************************/
3048 /* There are, it seems, broken clients out there that cannot handle multiline
3049 responses. If no_multiline_responses is TRUE (it can be set from an ACL), we
3050 output nothing for non-final calls, and only the first line for anything else.
3053 code SMTP code, may involve extended status codes
3054 codelen length of smtp code; if > 4 there's an ESC
3055 final FALSE if the last line isn't the final line
3056 msg message text, possibly containing newlines
3062 smtp_respond(uschar* code, int codelen, BOOL final, uschar *msg)
3067 if (!final && no_multiline_responses) return;
3072 esclen = codelen - 4;
3075 /* If this is the first output for a (non-batch) RCPT command, see if all RCPTs
3076 have had the same. Note: this code is also present in smtp_printf(). It would
3077 be tidier to have it only in one place, but when it was added, it was easier to
3078 do it that way, so as not to have to mess with the code for the RCPT command,
3079 which sometimes uses smtp_printf() and sometimes smtp_respond(). */
3081 if (rcpt_in_progress)
3083 if (rcpt_smtp_response == NULL)
3084 rcpt_smtp_response = string_copy(msg);
3085 else if (rcpt_smtp_response_same &&
3086 Ustrcmp(rcpt_smtp_response, msg) != 0)
3087 rcpt_smtp_response_same = FALSE;
3088 rcpt_in_progress = FALSE;
3091 /* Now output the message, splitting it up into multiple lines if necessary.
3092 We only handle pipelining these responses as far as nonfinal/final groups,
3093 not the whole MAIL/RCPT/DATA response set. */
3097 uschar *nl = Ustrchr(msg, '\n');
3100 smtp_printf("%.3s%c%.*s%s\r\n", !final, code, final ? ' ':'-', esclen, esc, msg);
3103 else if (nl[1] == 0 || no_multiline_responses)
3105 smtp_printf("%.3s%c%.*s%.*s\r\n", !final, code, final ? ' ':'-', esclen, esc,
3106 (int)(nl - msg), msg);
3111 smtp_printf("%.3s-%.*s%.*s\r\n", TRUE, code, esclen, esc, (int)(nl - msg), msg);
3113 while (isspace(*msg)) msg++;
3121 /*************************************************
3122 * Parse user SMTP message *
3123 *************************************************/
3125 /* This function allows for user messages overriding the response code details
3126 by providing a suitable response code string at the start of the message
3127 user_msg. Check the message for starting with a response code and optionally an
3128 extended status code. If found, check that the first digit is valid, and if so,
3129 change the code pointer and length to use the replacement. An invalid code
3130 causes a panic log; in this case, if the log messages is the same as the user
3131 message, we must also adjust the value of the log message to show the code that
3132 is actually going to be used (the original one).
3134 This function is global because it is called from receive.c as well as within
3137 Note that the code length returned includes the terminating whitespace
3138 character, which is always included in the regex match.
3141 code SMTP code, may involve extended status codes
3142 codelen length of smtp code; if > 4 there's an ESC
3144 log_msg optional log message, to be adjusted with the new SMTP code
3145 check_valid if true, verify the response code
3151 smtp_message_code(uschar **code, int *codelen, uschar **msg, uschar **log_msg,
3157 if (!msg || !*msg) return;
3159 if ((n = pcre_exec(regex_smtp_code, NULL, CS *msg, Ustrlen(*msg), 0,
3160 PCRE_EOPT, ovector, sizeof(ovector)/sizeof(int))) < 0) return;
3162 if (check_valid && (*msg)[0] != (*code)[0])
3164 log_write(0, LOG_MAIN|LOG_PANIC, "configured error code starts with "
3165 "incorrect digit (expected %c) in \"%s\"", (*code)[0], *msg);
3166 if (log_msg != NULL && *log_msg == *msg)
3167 *log_msg = string_sprintf("%s %s", *code, *log_msg + ovector[1]);
3172 *codelen = ovector[1]; /* Includes final space */
3174 *msg += ovector[1]; /* Chop the code off the message */
3181 /*************************************************
3182 * Handle an ACL failure *
3183 *************************************************/
3185 /* This function is called when acl_check() fails. As well as calls from within
3186 this module, it is called from receive.c for an ACL after DATA. It sorts out
3187 logging the incident, and sends the error response. A message containing
3188 newlines is turned into a multiline SMTP response, but for logging, only the
3191 There's a table of default permanent failure response codes to use in
3192 globals.c, along with the table of names. VFRY is special. Despite RFC1123 it
3193 defaults disabled in Exim. However, discussion in connection with RFC 821bis
3194 (aka RFC 2821) has concluded that the response should be 252 in the disabled
3195 state, because there are broken clients that try VRFY before RCPT. A 5xx
3196 response should be given only when the address is positively known to be
3197 undeliverable. Sigh. We return 252 if there is no VRFY ACL or it provides
3198 no explicit code, but if there is one we let it know best.
3199 Also, for ETRN, 458 is given on refusal, and for AUTH, 503.
3201 From Exim 4.63, it is possible to override the response code details by
3202 providing a suitable response code string at the start of the message provided
3203 in user_msg. The code's first digit is checked for validity.
3206 where where the ACL was called from
3208 user_msg a message that can be included in an SMTP response
3209 log_msg a message for logging
3211 Returns: 0 in most cases
3212 2 if the failure code was FAIL_DROP, in which case the
3213 SMTP connection should be dropped (this value fits with the
3214 "done" variable in smtp_setup_msg() below)
3218 smtp_handle_acl_fail(int where, int rc, uschar *user_msg, uschar *log_msg)
3220 BOOL drop = rc == FAIL_DROP;
3224 uschar *sender_info = US"";
3226 #ifdef WITH_CONTENT_SCAN
3227 where == ACL_WHERE_MIME ? US"during MIME ACL checks" :
3229 where == ACL_WHERE_PREDATA ? US"DATA" :
3230 where == ACL_WHERE_DATA ? US"after DATA" :
3231 #ifndef DISABLE_PRDR
3232 where == ACL_WHERE_PRDR ? US"after DATA PRDR" :
3235 string_sprintf("%s %s", acl_wherenames[where], smtp_cmd_data) :
3236 string_sprintf("%s in \"connect\" ACL", acl_wherenames[where]);
3238 if (drop) rc = FAIL;
3240 /* Set the default SMTP code, and allow a user message to change it. */
3242 smtp_code = rc == FAIL ? acl_wherecodes[where] : US"451";
3243 smtp_message_code(&smtp_code, &codelen, &user_msg, &log_msg,
3244 where != ACL_WHERE_VRFY);
3246 /* We used to have sender_address here; however, there was a bug that was not
3247 updating sender_address after a rewrite during a verify. When this bug was
3248 fixed, sender_address at this point became the rewritten address. I'm not sure
3249 this is what should be logged, so I've changed to logging the unrewritten
3250 address to retain backward compatibility. */
3252 #ifndef WITH_CONTENT_SCAN
3253 if (where == ACL_WHERE_RCPT || where == ACL_WHERE_DATA)
3255 if (where == ACL_WHERE_RCPT || where == ACL_WHERE_DATA || where == ACL_WHERE_MIME)
3258 sender_info = string_sprintf("F=<%s>%s%s%s%s ",
3259 sender_address_unrewritten ? sender_address_unrewritten : sender_address,
3260 sender_host_authenticated ? US" A=" : US"",
3261 sender_host_authenticated ? sender_host_authenticated : US"",
3262 sender_host_authenticated && authenticated_id ? US":" : US"",
3263 sender_host_authenticated && authenticated_id ? authenticated_id : US""
3267 /* If there's been a sender verification failure with a specific message, and
3268 we have not sent a response about it yet, do so now, as a preliminary line for
3269 failures, but not defers. However, always log it for defer, and log it for fail
3270 unless the sender_verify_fail log selector has been turned off. */
3272 if (sender_verified_failed &&
3273 !testflag(sender_verified_failed, af_sverify_told))
3275 BOOL save_rcpt_in_progress = rcpt_in_progress;
3276 rcpt_in_progress = FALSE; /* So as not to treat these as the error */
3278 setflag(sender_verified_failed, af_sverify_told);
3280 if (rc != FAIL || LOGGING(sender_verify_fail))
3281 log_write(0, LOG_MAIN|LOG_REJECT, "%s sender verify %s for <%s>%s",
3282 host_and_ident(TRUE),
3283 ((sender_verified_failed->special_action & 255) == DEFER)? "defer":"fail",
3284 sender_verified_failed->address,
3285 (sender_verified_failed->message == NULL)? US"" :
3286 string_sprintf(": %s", sender_verified_failed->message));
3288 if (rc == FAIL && sender_verified_failed->user_message)
3289 smtp_respond(smtp_code, codelen, FALSE, string_sprintf(
3290 testflag(sender_verified_failed, af_verify_pmfail)?
3291 "Postmaster verification failed while checking <%s>\n%s\n"
3292 "Several RFCs state that you are required to have a postmaster\n"
3293 "mailbox for each mail domain. This host does not accept mail\n"
3294 "from domains whose servers reject the postmaster address."
3296 testflag(sender_verified_failed, af_verify_nsfail)?
3297 "Callback setup failed while verifying <%s>\n%s\n"
3298 "The initial connection, or a HELO or MAIL FROM:<> command was\n"
3299 "rejected. Refusing MAIL FROM:<> does not help fight spam, disregards\n"
3300 "RFC requirements, and stops you from receiving standard bounce\n"
3301 "messages. This host does not accept mail from domains whose servers\n"
3304 "Verification failed for <%s>\n%s",
3305 sender_verified_failed->address,
3306 sender_verified_failed->user_message));
3308 rcpt_in_progress = save_rcpt_in_progress;
3311 /* Sort out text for logging */
3313 log_msg = log_msg ? string_sprintf(": %s", log_msg) : US"";
3314 if ((lognl = Ustrchr(log_msg, '\n'))) *lognl = 0;
3316 /* Send permanent failure response to the command, but the code used isn't
3317 always a 5xx one - see comments at the start of this function. If the original
3318 rc was FAIL_DROP we drop the connection and yield 2. */
3321 smtp_respond(smtp_code, codelen, TRUE,
3322 user_msg ? user_msg : US"Administrative prohibition");
3324 /* Send temporary failure response to the command. Don't give any details,
3325 unless acl_temp_details is set. This is TRUE for a callout defer, a "defer"
3326 verb, and for a header verify when smtp_return_error_details is set.
3328 This conditional logic is all somewhat of a mess because of the odd
3329 interactions between temp_details and return_error_details. One day it should
3330 be re-implemented in a tidier fashion. */
3333 if (acl_temp_details && user_msg)
3335 if ( smtp_return_error_details
3336 && sender_verified_failed
3337 && sender_verified_failed->message
3339 smtp_respond(smtp_code, codelen, FALSE, sender_verified_failed->message);
3341 smtp_respond(smtp_code, codelen, TRUE, user_msg);
3344 smtp_respond(smtp_code, codelen, TRUE,
3345 US"Temporary local problem - please try later");
3347 /* Log the incident to the logs that are specified by log_reject_target
3348 (default main, reject). This can be empty to suppress logging of rejections. If
3349 the connection is not forcibly to be dropped, return 0. Otherwise, log why it
3350 is closing if required and return 2. */
3352 if (log_reject_target != 0)
3355 gstring * g = s_tlslog(NULL);
3356 uschar * tls = string_from_gstring(g);
3357 if (!tls) tls = US"";
3359 uschar * tls = US"";
3361 log_write(where == ACL_WHERE_CONNECT ? L_connection_reject : 0,
3362 log_reject_target, "%s%s%s %s%srejected %s%s",
3363 LOGGING(dnssec) && sender_host_dnssec ? US" DS" : US"",
3364 host_and_ident(TRUE),
3367 rc == FAIL ? US"" : US"temporarily ",
3371 if (!drop) return 0;
3373 log_write(L_smtp_connection, LOG_MAIN, "%s closed by DROP in ACL",
3374 smtp_get_connection_info());
3376 /* Run the not-quit ACL, but without any custom messages. This should not be a
3377 problem, because we get here only if some other ACL has issued "drop", and
3378 in that case, *its* custom messages will have been used above. */
3380 smtp_notquit_exit(US"acl-drop", NULL, NULL);
3387 /*************************************************
3388 * Handle SMTP exit when QUIT is not given *
3389 *************************************************/
3391 /* This function provides a logging/statistics hook for when an SMTP connection
3392 is dropped on the floor or the other end goes away. It's a global function
3393 because it's called from receive.c as well as this module. As well as running
3394 the NOTQUIT ACL, if there is one, this function also outputs a final SMTP
3395 response, either with a custom message from the ACL, or using a default. There
3396 is one case, however, when no message is output - after "drop". In that case,
3397 the ACL that obeyed "drop" has already supplied the custom message, and NULL is
3398 passed to this function.
3400 In case things go wrong while processing this function, causing an error that
3401 may re-enter this function, there is a recursion check.
3404 reason What $smtp_notquit_reason will be set to in the ACL;
3405 if NULL, the ACL is not run
3406 code The error code to return as part of the response
3407 defaultrespond The default message if there's no user_msg
3413 smtp_notquit_exit(uschar *reason, uschar *code, uschar *defaultrespond, ...)
3416 uschar *user_msg = NULL;
3417 uschar *log_msg = NULL;
3419 /* Check for recursive acll */
3421 if (smtp_exit_function_called)
3423 log_write(0, LOG_PANIC, "smtp_notquit_exit() called more than once (%s)",
3427 smtp_exit_function_called = TRUE;
3429 /* Call the not-QUIT ACL, if there is one, unless no reason is given. */
3431 if (acl_smtp_notquit && reason)
3433 smtp_notquit_reason = reason;
3434 if ((rc = acl_check(ACL_WHERE_NOTQUIT, NULL, acl_smtp_notquit, &user_msg,
3435 &log_msg)) == ERROR)
3436 log_write(0, LOG_MAIN|LOG_PANIC, "ACL for not-QUIT returned ERROR: %s",
3440 /* Write an SMTP response if we are expected to give one. As the default
3441 responses are all internal, they should always fit in the buffer, but code a
3442 warning, just in case. Note that string_vformat() still leaves a complete
3443 string, even if it is incomplete. */
3445 if (code && defaultrespond)
3448 smtp_respond(code, 3, TRUE, user_msg);
3453 va_start(ap, defaultrespond);
3454 if (!string_vformat(buffer, sizeof(buffer), CS defaultrespond, ap))
3455 log_write(0, LOG_MAIN|LOG_PANIC, "string too large in smtp_notquit_exit()");
3456 smtp_printf("%s %s\r\n", FALSE, code, buffer);
3466 /*************************************************
3467 * Verify HELO argument *
3468 *************************************************/
3470 /* This function is called if helo_verify_hosts or helo_try_verify_hosts is
3471 matched. It is also called from ACL processing if verify = helo is used and
3472 verification was not previously tried (i.e. helo_try_verify_hosts was not
3473 matched). The result of its processing is to set helo_verified and
3474 helo_verify_failed. These variables should both be FALSE for this function to
3477 Note that EHLO/HELO is legitimately allowed to quote an address literal. Allow
3478 for IPv6 ::ffff: literals.
3481 Returns: TRUE if testing was completed;
3482 FALSE on a temporary failure
3486 smtp_verify_helo(void)
3490 HDEBUG(D_receive) debug_printf("verifying EHLO/HELO argument \"%s\"\n",
3493 if (sender_helo_name == NULL)
3495 HDEBUG(D_receive) debug_printf("no EHLO/HELO command was issued\n");
3498 /* Deal with the case of -bs without an IP address */
3500 else if (sender_host_address == NULL)
3502 HDEBUG(D_receive) debug_printf("no client IP address: assume success\n");
3503 helo_verified = TRUE;
3506 /* Deal with the more common case when there is a sending IP address */
3508 else if (sender_helo_name[0] == '[')
3510 helo_verified = Ustrncmp(sender_helo_name+1, sender_host_address,
3511 Ustrlen(sender_host_address)) == 0;
3516 if (strncmpic(sender_host_address, US"::ffff:", 7) == 0)
3517 helo_verified = Ustrncmp(sender_helo_name + 1,
3518 sender_host_address + 7, Ustrlen(sender_host_address) - 7) == 0;
3523 { if (helo_verified) debug_printf("matched host address\n"); }
3526 /* Do a reverse lookup if one hasn't already given a positive or negative
3527 response. If that fails, or the name doesn't match, try checking with a forward
3532 if (sender_host_name == NULL && !host_lookup_failed)
3533 yield = host_name_lookup() != DEFER;
3535 /* If a host name is known, check it and all its aliases. */
3537 if (sender_host_name)
3538 if ((helo_verified = strcmpic(sender_host_name, sender_helo_name) == 0))
3540 sender_helo_dnssec = sender_host_dnssec;
3541 HDEBUG(D_receive) debug_printf("matched host name\n");
3545 uschar **aliases = sender_host_aliases;
3547 if ((helo_verified = strcmpic(*aliases++, sender_helo_name) == 0))
3549 sender_helo_dnssec = sender_host_dnssec;
3553 HDEBUG(D_receive) if (helo_verified)
3554 debug_printf("matched alias %s\n", *(--aliases));
3557 /* Final attempt: try a forward lookup of the helo name */
3566 h.name = sender_helo_name;
3573 HDEBUG(D_receive) debug_printf("getting IP address for %s\n",
3575 rc = host_find_bydns(&h, NULL, HOST_FIND_BY_A | HOST_FIND_BY_AAAA,
3576 NULL, NULL, NULL, &d, NULL, NULL);
3577 if (rc == HOST_FOUND || rc == HOST_FOUND_LOCAL)
3578 for (hh = &h; hh; hh = hh->next)
3579 if (Ustrcmp(hh->address, sender_host_address) == 0)
3581 helo_verified = TRUE;
3582 if (h.dnssec == DS_YES) sender_helo_dnssec = TRUE;
3585 debug_printf("IP address for %s matches calling address\n"
3586 "Forward DNS security status: %sverified\n",
3587 sender_helo_name, sender_helo_dnssec ? "" : "un");
3594 if (!helo_verified) helo_verify_failed = TRUE; /* We've tried ... */
3601 /*************************************************
3602 * Send user response message *
3603 *************************************************/
3605 /* This function is passed a default response code and a user message. It calls
3606 smtp_message_code() to check and possibly modify the response code, and then
3607 calls smtp_respond() to transmit the response. I put this into a function
3608 just to avoid a lot of repetition.
3611 code the response code
3612 user_msg the user message
3618 smtp_user_msg(uschar *code, uschar *user_msg)
3621 smtp_message_code(&code, &len, &user_msg, NULL, TRUE);
3622 smtp_respond(code, len, TRUE, user_msg);
3628 smtp_in_auth(auth_instance *au, uschar ** s, uschar ** ss)
3630 const uschar *set_id = NULL;
3633 /* Run the checking code, passing the remainder of the command line as
3634 data. Initials the $auth<n> variables as empty. Initialize $0 empty and set
3635 it as the only set numerical variable. The authenticator may set $auth<n>
3636 and also set other numeric variables. The $auth<n> variables are preferred
3637 nowadays; the numerical variables remain for backwards compatibility.
3639 Afterwards, have a go at expanding the set_id string, even if
3640 authentication failed - for bad passwords it can be useful to log the
3641 userid. On success, require set_id to expand and exist, and put it in
3642 authenticated_id. Save this in permanent store, as the working store gets
3643 reset at HELO, RSET, etc. */
3645 for (i = 0; i < AUTH_VARS; i++) auth_vars[i] = NULL;
3647 expand_nlength[0] = 0; /* $0 contains nothing */
3649 rc = (au->info->servercode)(au, smtp_cmd_data);
3650 if (au->set_id) set_id = expand_string(au->set_id);
3651 expand_nmax = -1; /* Reset numeric variables */
3652 for (i = 0; i < AUTH_VARS; i++) auth_vars[i] = NULL; /* Reset $auth<n> */
3654 /* The value of authenticated_id is stored in the spool file and printed in
3655 log lines. It must not contain binary zeros or newline characters. In
3656 normal use, it never will, but when playing around or testing, this error
3657 can (did) happen. To guard against this, ensure that the id contains only
3658 printing characters. */
3660 if (set_id) set_id = string_printing(set_id);
3662 /* For the non-OK cases, set up additional logging data if set_id
3666 set_id = set_id && *set_id
3667 ? string_sprintf(" (set_id=%s)", set_id) : US"";
3669 /* Switch on the result */
3674 if (!au->set_id || set_id) /* Complete success */
3676 if (set_id) authenticated_id = string_copy_malloc(set_id);
3677 sender_host_authenticated = au->name;
3678 sender_host_auth_pubname = au->public_name;
3679 authentication_failed = FALSE;
3680 authenticated_fail_id = NULL; /* Impossible to already be set? */
3683 (sender_host_address ? protocols : protocols_local)
3684 [pextend + pauthed + (tls_in.active >= 0 ? pcrpted:0)];
3685 *s = *ss = US"235 Authentication succeeded";
3686 authenticated_by = au;
3690 /* Authentication succeeded, but we failed to expand the set_id string.
3691 Treat this as a temporary error. */
3693 auth_defer_msg = expand_string_message;
3697 if (set_id) authenticated_fail_id = string_copy_malloc(set_id);
3698 *s = string_sprintf("435 Unable to authenticate at present%s",
3699 auth_defer_user_msg);
3700 *ss = string_sprintf("435 Unable to authenticate at present%s: %s",
3701 set_id, auth_defer_msg);
3705 *s = *ss = US"501 Invalid base64 data";
3709 *s = *ss = US"501 Authentication cancelled";
3713 *s = *ss = US"553 Initial data not expected";
3717 if (set_id) authenticated_fail_id = string_copy_malloc(set_id);
3718 *s = US"535 Incorrect authentication data";
3719 *ss = string_sprintf("535 Incorrect authentication data%s", set_id);
3723 if (set_id) authenticated_fail_id = string_copy_malloc(set_id);
3724 *s = US"435 Internal error";
3725 *ss = string_sprintf("435 Internal error%s: return %d from authentication "
3726 "check", set_id, rc);
3738 qualify_recipient(uschar ** recipient, uschar * smtp_cmd_data, uschar * tag)
3741 if (allow_unqualified_recipient || strcmpic(*recipient, US"postmaster") == 0)
3743 DEBUG(D_receive) debug_printf("unqualified address %s accepted\n",
3745 rd = Ustrlen(recipient) + 1;
3746 *recipient = rewrite_address_qualify(*recipient, TRUE);
3749 smtp_printf("501 %s: recipient address must contain a domain\r\n", FALSE,
3751 log_write(L_smtp_syntax_error,
3752 LOG_MAIN|LOG_REJECT, "unqualified %s rejected: <%s> %s%s",
3753 tag, *recipient, host_and_ident(TRUE), host_lookup_msg);
3761 smtp_quit_handler(uschar ** user_msgp, uschar ** log_msgp)
3764 incomplete_transaction_log(US"QUIT");
3767 int rc = acl_check(ACL_WHERE_QUIT, NULL, acl_smtp_quit, user_msgp, log_msgp);
3769 log_write(0, LOG_MAIN|LOG_PANIC, "ACL for QUIT returned ERROR: %s",
3773 smtp_respond(US"221", 3, TRUE, *user_msgp);
3775 smtp_printf("221 %s closing connection\r\n", FALSE, smtp_active_hostname);
3778 tls_close(TRUE, TLS_SHUTDOWN_NOWAIT);
3781 log_write(L_smtp_connection, LOG_MAIN, "%s closed by QUIT",
3782 smtp_get_connection_info());
3787 smtp_rset_handler(void)
3790 incomplete_transaction_log(US"RSET");
3791 smtp_printf("250 Reset OK\r\n", FALSE);
3792 cmd_list[CMD_LIST_RSET].is_mail_cmd = FALSE;
3797 /*************************************************
3798 * Initialize for SMTP incoming message *
3799 *************************************************/
3801 /* This function conducts the initial dialogue at the start of an incoming SMTP
3802 message, and builds a list of recipients. However, if the incoming message
3803 is part of a batch (-bS option) a separate function is called since it would
3804 be messy having tests splattered about all over this function. This function
3805 therefore handles the case where interaction is occurring. The input and output
3806 files are set up in smtp_in and smtp_out.
3808 The global recipients_list is set to point to a vector of recipient_item
3809 blocks, whose number is given by recipients_count. This is extended by the
3810 receive_add_recipient() function. The global variable sender_address is set to
3811 the sender's address. The yield is +1 if a message has been successfully
3812 started, 0 if a QUIT command was encountered or the connection was refused from
3813 the particular host, or -1 if the connection was lost.
3817 Returns: > 0 message successfully started (reached DATA)
3818 = 0 QUIT read or end of file reached or call refused
3823 smtp_setup_msg(void)
3826 BOOL toomany = FALSE;
3827 BOOL discarded = FALSE;
3828 BOOL last_was_rej_mail = FALSE;
3829 BOOL last_was_rcpt = FALSE;
3830 void *reset_point = store_get(0);
3832 DEBUG(D_receive) debug_printf("smtp_setup_msg entered\n");
3834 /* Reset for start of new message. We allow one RSET not to be counted as a
3835 nonmail command, for those MTAs that insist on sending it between every
3836 message. Ditto for EHLO/HELO and for STARTTLS, to allow for going in and out of
3837 TLS between messages (an Exim client may do this if it has messages queued up
3838 for the host). Note: we do NOT reset AUTH at this point. */
3840 smtp_reset(reset_point);
3841 message_ended = END_NOTSTARTED;
3843 chunking_state = chunking_offered ? CHUNKING_OFFERED : CHUNKING_NOT_OFFERED;
3845 cmd_list[CMD_LIST_RSET].is_mail_cmd = TRUE;
3846 cmd_list[CMD_LIST_HELO].is_mail_cmd = TRUE;
3847 cmd_list[CMD_LIST_EHLO].is_mail_cmd = TRUE;
3849 cmd_list[CMD_LIST_STARTTLS].is_mail_cmd = TRUE;
3852 /* Set the local signal handler for SIGTERM - it tries to end off tidily */
3854 had_command_sigterm = 0;
3855 os_non_restarting_signal(SIGTERM, command_sigterm_handler);
3857 /* Batched SMTP is handled in a different function. */
3859 if (smtp_batched_input) return smtp_setup_batch_msg();
3861 /* Deal with SMTP commands. This loop is exited by setting done to a POSITIVE
3862 value. The values are 2 larger than the required yield of the function. */
3866 const uschar **argv;
3867 uschar *etrn_command;
3868 uschar *etrn_serialize_key;
3870 uschar *log_msg, *smtp_code;
3871 uschar *user_msg = NULL;
3872 uschar *recipient = NULL;
3873 uschar *hello = NULL;
3875 BOOL was_rej_mail = FALSE;
3876 BOOL was_rcpt = FALSE;
3877 void (*oldsignal)(int);
3879 int start, end, sender_domain, recipient_domain;
3883 uschar *orcpt = NULL;
3888 /* Check once per STARTTLS or SSL-on-connect for a TLS AUTH */
3889 if ( tls_in.active >= 0
3891 && tls_in.certificate_verified
3892 && cmd_list[CMD_LIST_TLS_AUTH].is_mail_cmd
3895 cmd_list[CMD_LIST_TLS_AUTH].is_mail_cmd = FALSE;
3897 for (au = auths; au; au = au->next)
3898 if (strcmpic(US"tls", au->driver_name) == 0)
3901 && (rc = acl_check(ACL_WHERE_AUTH, NULL, acl_smtp_auth,
3902 &user_msg, &log_msg)) != OK
3904 done = smtp_handle_acl_fail(ACL_WHERE_AUTH, rc, user_msg, log_msg);
3907 smtp_cmd_data = NULL;
3909 if (smtp_in_auth(au, &s, &ss) == OK)
3910 { DEBUG(D_auth) debug_printf("tls auth succeeded\n"); }
3912 { DEBUG(D_auth) debug_printf("tls auth not succeeded\n"); }
3920 if (smtp_in) /* Avoid pure-ACKs while in cmd pingpong phase */
3921 (void) setsockopt(fileno(smtp_in), IPPROTO_TCP, TCP_QUICKACK,
3922 US &off, sizeof(off));
3925 switch(smtp_read_command(TRUE, GETC_BUFFER_UNLIMITED))
3927 /* The AUTH command is not permitted to occur inside a transaction, and may
3928 occur successfully only once per connection. Actually, that isn't quite
3929 true. When TLS is started, all previous information about a connection must
3930 be discarded, so a new AUTH is permitted at that time.
3932 AUTH may only be used when it has been advertised. However, it seems that
3933 there are clients that send AUTH when it hasn't been advertised, some of
3934 them even doing this after HELO. And there are MTAs that accept this. Sigh.
3935 So there's a get-out that allows this to happen.
3937 AUTH is initially labelled as a "nonmail command" so that one occurrence
3938 doesn't get counted. We change the label here so that multiple failing
3939 AUTHS will eventually hit the nonmail threshold. */
3943 authentication_failed = TRUE;
3944 cmd_list[CMD_LIST_AUTH].is_mail_cmd = FALSE;
3946 if (!auth_advertised && !allow_auth_unadvertised)
3948 done = synprot_error(L_smtp_protocol_error, 503, NULL,
3949 US"AUTH command used when not advertised");
3952 if (sender_host_authenticated)
3954 done = synprot_error(L_smtp_protocol_error, 503, NULL,
3955 US"already authenticated");
3960 done = synprot_error(L_smtp_protocol_error, 503, NULL,
3961 US"not permitted in mail transaction");
3968 && (rc = acl_check(ACL_WHERE_AUTH, NULL, acl_smtp_auth,
3969 &user_msg, &log_msg)) != OK
3972 done = smtp_handle_acl_fail(ACL_WHERE_AUTH, rc, user_msg, log_msg);
3976 /* Find the name of the requested authentication mechanism. */
3979 while ((c = *smtp_cmd_data) != 0 && !isspace(c))
3981 if (!isalnum(c) && c != '-' && c != '_')
3983 done = synprot_error(L_smtp_syntax_error, 501, NULL,
3984 US"invalid character in authentication mechanism name");
3990 /* If not at the end of the line, we must be at white space. Terminate the
3991 name and move the pointer on to any data that may be present. */
3993 if (*smtp_cmd_data != 0)
3995 *smtp_cmd_data++ = 0;
3996 while (isspace(*smtp_cmd_data)) smtp_cmd_data++;
3999 /* Search for an authentication mechanism which is configured for use
4000 as a server and which has been advertised (unless, sigh, allow_auth_
4001 unadvertised is set). */
4003 for (au = auths; au; au = au->next)
4004 if (strcmpic(s, au->public_name) == 0 && au->server &&
4005 (au->advertised || allow_auth_unadvertised))
4010 c = smtp_in_auth(au, &s, &ss);
4012 smtp_printf("%s\r\n", FALSE, s);
4014 log_write(0, LOG_MAIN|LOG_REJECT, "%s authenticator failed for %s: %s",
4015 au->name, host_and_ident(FALSE), ss);
4018 done = synprot_error(L_smtp_protocol_error, 504, NULL,
4019 string_sprintf("%s authentication mechanism not supported", s));
4021 break; /* AUTH_CMD */
4023 /* The HELO/EHLO commands are permitted to appear in the middle of a
4024 session as well as at the beginning. They have the effect of a reset in
4025 addition to their other functions. Their absence at the start cannot be
4026 taken to be an error.
4030 If the EHLO command is not acceptable to the SMTP server, 501, 500,
4031 or 502 failure replies MUST be returned as appropriate. The SMTP
4032 server MUST stay in the same state after transmitting these replies
4033 that it was in before the EHLO was received.
4035 Therefore, we do not do the reset until after checking the command for
4036 acceptability. This change was made for Exim release 4.11. Previously
4037 it did the reset first. */
4050 HELO_EHLO: /* Common code for HELO and EHLO */
4051 cmd_list[CMD_LIST_HELO].is_mail_cmd = FALSE;
4052 cmd_list[CMD_LIST_EHLO].is_mail_cmd = FALSE;
4054 /* Reject the HELO if its argument was invalid or non-existent. A
4055 successful check causes the argument to be saved in malloc store. */
4057 if (!check_helo(smtp_cmd_data))
4059 smtp_printf("501 Syntactically invalid %s argument(s)\r\n", FALSE, hello);
4061 log_write(0, LOG_MAIN|LOG_REJECT, "rejected %s from %s: syntactically "
4062 "invalid argument(s): %s", hello, host_and_ident(FALSE),
4063 (*smtp_cmd_argument == 0)? US"(no argument given)" :
4064 string_printing(smtp_cmd_argument));
4066 if (++synprot_error_count > smtp_max_synprot_errors)
4068 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
4069 "syntax or protocol errors (last command was \"%s\")",
4070 host_and_ident(FALSE), string_printing(smtp_cmd_buffer));
4077 /* If sender_host_unknown is true, we have got here via the -bs interface,
4078 not called from inetd. Otherwise, we are running an IP connection and the
4079 host address will be set. If the helo name is the primary name of this
4080 host and we haven't done a reverse lookup, force one now. If helo_required
4081 is set, ensure that the HELO name matches the actual host. If helo_verify
4082 is set, do the same check, but softly. */
4084 if (!sender_host_unknown)
4086 BOOL old_helo_verified = helo_verified;
4087 uschar *p = smtp_cmd_data;
4089 while (*p != 0 && !isspace(*p)) { *p = tolower(*p); p++; }
4092 /* Force a reverse lookup if HELO quoted something in helo_lookup_domains
4093 because otherwise the log can be confusing. */
4095 if ( !sender_host_name
4096 && (deliver_domain = sender_helo_name, /* set $domain */
4097 match_isinlist(sender_helo_name, CUSS &helo_lookup_domains, 0,
4098 &domainlist_anchor, NULL, MCL_DOMAIN, TRUE, NULL)) == OK)
4099 (void)host_name_lookup();
4101 /* Rebuild the fullhost info to include the HELO name (and the real name
4102 if it was looked up.) */
4104 host_build_sender_fullhost(); /* Rebuild */
4105 set_process_info("handling%s incoming connection from %s",
4106 (tls_in.active >= 0)? " TLS" : "", host_and_ident(FALSE));
4108 /* Verify if configured. This doesn't give much security, but it does
4109 make some people happy to be able to do it. If helo_required is set,
4110 (host matches helo_verify_hosts) failure forces rejection. If helo_verify
4111 is set (host matches helo_try_verify_hosts), it does not. This is perhaps
4112 now obsolescent, since the verification can now be requested selectively
4115 helo_verified = helo_verify_failed = sender_helo_dnssec = FALSE;
4116 if (helo_required || helo_verify)
4118 BOOL tempfail = !smtp_verify_helo();
4123 smtp_printf("%d %s argument does not match calling host\r\n", FALSE,
4124 tempfail? 451 : 550, hello);
4125 log_write(0, LOG_MAIN|LOG_REJECT, "%srejected \"%s %s\" from %s",
4126 tempfail? "temporarily " : "",
4127 hello, sender_helo_name, host_and_ident(FALSE));
4128 helo_verified = old_helo_verified;
4129 break; /* End of HELO/EHLO processing */
4131 HDEBUG(D_all) debug_printf("%s verification failed but host is in "
4132 "helo_try_verify_hosts\n", hello);
4138 /* set up SPF context */
4139 spf_init(sender_helo_name, sender_host_address);
4142 /* Apply an ACL check if one is defined; afterwards, recheck
4143 synchronization in case the client started sending in a delay. */
4146 if ((rc = acl_check(ACL_WHERE_HELO, NULL, acl_smtp_helo,
4147 &user_msg, &log_msg)) != OK)
4149 done = smtp_handle_acl_fail(ACL_WHERE_HELO, rc, user_msg, log_msg);
4150 if (sender_helo_name)
4152 store_free(sender_helo_name);
4153 sender_helo_name = NULL;
4155 host_build_sender_fullhost(); /* Rebuild */
4158 else if (!check_sync()) goto SYNC_FAILURE;
4160 /* Generate an OK reply. The default string includes the ident if present,
4161 and also the IP address if present. Reflecting back the ident is intended
4162 as a deterrent to mail forgers. For maximum efficiency, and also because
4163 some broken systems expect each response to be in a single packet, arrange
4164 that the entire reply is sent in one write(). */
4166 auth_advertised = FALSE;
4167 pipelining_advertised = FALSE;
4169 tls_advertised = FALSE;
4171 dsn_advertised = FALSE;
4173 smtputf8_advertised = FALSE;
4176 smtp_code = US"250 "; /* Default response code plus space*/
4179 s = string_sprintf("%.3s %s Hello %s%s%s",
4181 smtp_active_hostname,
4182 sender_ident ? sender_ident : US"",
4183 sender_ident ? US" at " : US"",
4184 sender_host_name ? sender_host_name : sender_helo_name);
4185 g = string_cat(NULL, s);
4187 if (sender_host_address)
4189 g = string_catn(g, US" [", 2);
4190 g = string_cat (g, sender_host_address);
4191 g = string_catn(g, US"]", 1);
4195 /* A user-supplied EHLO greeting may not contain more than one line. Note
4196 that the code returned by smtp_message_code() includes the terminating
4197 whitespace character. */
4203 smtp_message_code(&smtp_code, &codelen, &user_msg, NULL, TRUE);
4204 s = string_sprintf("%.*s%s", codelen, smtp_code, user_msg);
4205 if ((ss = strpbrk(CS s, "\r\n")) != NULL)
4207 log_write(0, LOG_MAIN|LOG_PANIC, "EHLO/HELO response must not contain "
4208 "newlines: message truncated: %s", string_printing(s));
4211 g = string_cat(NULL, s);
4214 g = string_catn(g, US"\r\n", 2);
4216 /* If we received EHLO, we must create a multiline response which includes
4217 the functions supported. */
4223 /* I'm not entirely happy with this, as an MTA is supposed to check
4224 that it has enough room to accept a message of maximum size before
4225 it sends this. However, there seems little point in not sending it.
4226 The actual size check happens later at MAIL FROM time. By postponing it
4227 till then, VRFY and EXPN can be used after EHLO when space is short. */
4229 if (thismessage_size_limit > 0)
4231 sprintf(CS big_buffer, "%.3s-SIZE %d\r\n", smtp_code,
4232 thismessage_size_limit);
4233 g = string_cat(g, big_buffer);
4237 g = string_catn(g, smtp_code, 3);
4238 g = string_catn(g, US"-SIZE\r\n", 7);
4241 /* Exim does not do protocol conversion or data conversion. It is 8-bit
4242 clean; if it has an 8-bit character in its hand, it just sends it. It
4243 cannot therefore specify 8BITMIME and remain consistent with the RFCs.
4244 However, some users want this option simply in order to stop MUAs
4245 mangling messages that contain top-bit-set characters. It is therefore
4246 provided as an option. */
4248 if (accept_8bitmime)
4250 g = string_catn(g, smtp_code, 3);
4251 g = string_catn(g, US"-8BITMIME\r\n", 11);
4254 /* Advertise DSN support if configured to do so. */
4255 if (verify_check_host(&dsn_advertise_hosts) != FAIL)
4257 g = string_catn(g, smtp_code, 3);
4258 g = string_catn(g, US"-DSN\r\n", 6);
4259 dsn_advertised = TRUE;
4262 /* Advertise ETRN/VRFY/EXPN if there's are ACL checking whether a host is
4263 permitted to issue them; a check is made when any host actually tries. */
4267 g = string_catn(g, smtp_code, 3);
4268 g = string_catn(g, US"-ETRN\r\n", 7);
4272 g = string_catn(g, smtp_code, 3);
4273 g = string_catn(g, US"-VRFY\r\n", 7);
4277 g = string_catn(g, smtp_code, 3);
4278 g = string_catn(g, US"-EXPN\r\n", 7);
4281 /* Exim is quite happy with pipelining, so let the other end know that
4282 it is safe to use it, unless advertising is disabled. */
4284 if (pipelining_enable &&
4285 verify_check_host(&pipelining_advertise_hosts) == OK)
4287 g = string_catn(g, smtp_code, 3);
4288 g = string_catn(g, US"-PIPELINING\r\n", 13);
4289 sync_cmd_limit = NON_SYNC_CMD_PIPELINING;
4290 pipelining_advertised = TRUE;
4294 /* If any server authentication mechanisms are configured, advertise
4295 them if the current host is in auth_advertise_hosts. The problem with
4296 advertising always is that some clients then require users to
4297 authenticate (and aren't configurable otherwise) even though it may not
4298 be necessary (e.g. if the host is in host_accept_relay).
4300 RFC 2222 states that SASL mechanism names contain only upper case
4301 letters, so output the names in upper case, though we actually recognize
4302 them in either case in the AUTH command. */
4306 && !sender_host_authenticated
4308 && verify_check_host(&auth_advertise_hosts) == OK
4313 for (au = auths; au; au = au->next)
4315 au->advertised = FALSE;
4318 DEBUG(D_auth+D_expand) debug_printf_indent(
4319 "Evaluating advertise_condition for %s athenticator\n",
4321 if ( !au->advertise_condition
4322 || expand_check_condition(au->advertise_condition, au->name,
4329 g = string_catn(g, smtp_code, 3);
4330 g = string_catn(g, US"-AUTH", 5);
4332 auth_advertised = TRUE;
4335 g = string_catn(g, US" ", 1);
4336 g = string_cat (g, au->public_name);
4337 while (++saveptr < g->ptr) g->s[saveptr] = toupper(g->s[saveptr]);
4338 au->advertised = TRUE;
4343 if (!first) g = string_catn(g, US"\r\n", 2);
4346 /* RFC 3030 CHUNKING */
4348 if (verify_check_host(&chunking_advertise_hosts) != FAIL)
4350 g = string_catn(g, smtp_code, 3);
4351 g = string_catn(g, US"-CHUNKING\r\n", 11);
4352 chunking_offered = TRUE;
4353 chunking_state = CHUNKING_OFFERED;
4356 /* Advertise TLS (Transport Level Security) aka SSL (Secure Socket Layer)
4357 if it has been included in the binary, and the host matches
4358 tls_advertise_hosts. We must *not* advertise if we are already in a
4359 secure connection. */
4362 if (tls_in.active < 0 &&
4363 verify_check_host(&tls_advertise_hosts) != FAIL)
4365 g = string_catn(g, smtp_code, 3);
4366 g = string_catn(g, US"-STARTTLS\r\n", 11);
4367 tls_advertised = TRUE;
4371 #ifndef DISABLE_PRDR
4372 /* Per Recipient Data Response, draft by Eric A. Hall extending RFC */
4375 g = string_catn(g, smtp_code, 3);
4376 g = string_catn(g, US"-PRDR\r\n", 7);
4381 if ( accept_8bitmime
4382 && verify_check_host(&smtputf8_advertise_hosts) != FAIL)
4384 g = string_catn(g, smtp_code, 3);
4385 g = string_catn(g, US"-SMTPUTF8\r\n", 11);
4386 smtputf8_advertised = TRUE;
4390 /* Finish off the multiline reply with one that is always available. */
4392 g = string_catn(g, smtp_code, 3);
4393 g = string_catn(g, US" HELP\r\n", 7);
4396 /* Terminate the string (for debug), write it, and note that HELO/EHLO
4400 if (tls_in.active >= 0) (void)tls_write(TRUE, g->s, g->ptr, FALSE); else
4404 int i = fwrite(g->s, 1, g->ptr, smtp_out); i = i; /* compiler quietening */
4410 (void) string_from_gstring(g);
4411 while ((cr = Ustrchr(g->s, '\r')) != NULL) /* lose CRs */
4412 memmove(cr, cr + 1, (g->ptr--) - (cr - g->s));
4413 debug_printf("SMTP>> %s", g->s);
4417 /* Reset the protocol and the state, abandoning any previous message. */
4419 (sender_host_address ? protocols : protocols_local)
4421 ? pextend + (sender_host_authenticated ? pauthed : 0)
4423 + (tls_in.active >= 0 ? pcrpted : 0)
4425 cancel_cutthrough_connection(TRUE, US"sent EHLO response");
4426 smtp_reset(reset_point);
4428 break; /* HELO/EHLO */
4431 /* The MAIL command requires an address as an operand. All we do
4432 here is to parse it for syntactic correctness. The form "<>" is
4433 a special case which converts into an empty string. The start/end
4434 pointers in the original are not used further for this address, as
4435 it is the canonical extracted address which is all that is kept. */
4439 smtp_mailcmd_count++; /* Count for limit and ratelimit */
4440 was_rej_mail = TRUE; /* Reset if accepted */
4441 env_mail_type_t * mail_args; /* Sanity check & validate args */
4443 if (helo_required && !helo_seen)
4445 smtp_printf("503 HELO or EHLO required\r\n", FALSE);
4446 log_write(0, LOG_MAIN|LOG_REJECT, "rejected MAIL from %s: no "
4447 "HELO/EHLO given", host_and_ident(FALSE));
4451 if (sender_address != NULL)
4453 done = synprot_error(L_smtp_protocol_error, 503, NULL,
4454 US"sender already given");
4458 if (smtp_cmd_data[0] == 0)
4460 done = synprot_error(L_smtp_protocol_error, 501, NULL,
4461 US"MAIL must have an address operand");
4465 /* Check to see if the limit for messages per connection would be
4466 exceeded by accepting further messages. */
4468 if (smtp_accept_max_per_connection > 0 &&
4469 smtp_mailcmd_count > smtp_accept_max_per_connection)
4471 smtp_printf("421 too many messages in this connection\r\n", FALSE);
4472 log_write(0, LOG_MAIN|LOG_REJECT, "rejected MAIL command %s: too many "
4473 "messages in one connection", host_and_ident(TRUE));
4477 /* Reset for start of message - even if this is going to fail, we
4478 obviously need to throw away any previous data. */
4480 cancel_cutthrough_connection(TRUE, US"MAIL received");
4481 smtp_reset(reset_point);
4483 sender_data = recipient_data = NULL;
4485 /* Loop, checking for ESMTP additions to the MAIL FROM command. */
4489 uschar *name, *value, *end;
4490 unsigned long int size;
4491 BOOL arg_error = FALSE;
4493 if (!extract_option(&name, &value)) break;
4495 for (mail_args = env_mail_type_list;
4496 mail_args->value != ENV_MAIL_OPT_NULL;
4499 if (strcmpic(name, mail_args->name) == 0)
4501 if (mail_args->need_value && strcmpic(value, US"") == 0)
4504 switch(mail_args->value)
4506 /* Handle SIZE= by reading the value. We don't do the check till later,
4507 in order to be able to log the sender address on failure. */
4508 case ENV_MAIL_OPT_SIZE:
4509 if (((size = Ustrtoul(value, &end, 10)), *end == 0))
4511 if ((size == ULONG_MAX && errno == ERANGE) || size > INT_MAX)
4513 message_size = (int)size;
4519 /* If this session was initiated with EHLO and accept_8bitmime is set,
4520 Exim will have indicated that it supports the BODY=8BITMIME option. In
4521 fact, it does not support this according to the RFCs, in that it does not
4522 take any special action for forwarding messages containing 8-bit
4523 characters. That is why accept_8bitmime is not the default setting, but
4524 some sites want the action that is provided. We recognize both "8BITMIME"
4525 and "7BIT" as body types, but take no action. */
4526 case ENV_MAIL_OPT_BODY:
4527 if (accept_8bitmime) {
4528 if (strcmpic(value, US"8BITMIME") == 0)
4530 else if (strcmpic(value, US"7BIT") == 0)
4535 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4536 US"invalid data for BODY");
4539 DEBUG(D_receive) debug_printf("8BITMIME: %d\n", body_8bitmime);
4545 /* Handle the two DSN options, but only if configured to do so (which
4546 will have caused "DSN" to be given in the EHLO response). The code itself
4547 is included only if configured in at build time. */
4549 case ENV_MAIL_OPT_RET:
4552 /* Check if RET has already been set */
4555 synprot_error(L_smtp_syntax_error, 501, NULL,
4556 US"RET can be specified once only");
4559 dsn_ret = strcmpic(value, US"HDRS") == 0
4561 : strcmpic(value, US"FULL") == 0
4564 DEBUG(D_receive) debug_printf("DSN_RET: %d\n", dsn_ret);
4565 /* Check for invalid invalid value, and exit with error */
4568 synprot_error(L_smtp_syntax_error, 501, NULL,
4569 US"Value for RET is invalid");
4574 case ENV_MAIL_OPT_ENVID:
4577 /* Check if the dsn envid has been already set */
4578 if (dsn_envid != NULL)
4580 synprot_error(L_smtp_syntax_error, 501, NULL,
4581 US"ENVID can be specified once only");
4584 dsn_envid = string_copy(value);
4585 DEBUG(D_receive) debug_printf("DSN_ENVID: %s\n", dsn_envid);
4589 /* Handle the AUTH extension. If the value given is not "<>" and either
4590 the ACL says "yes" or there is no ACL but the sending host is
4591 authenticated, we set it up as the authenticated sender. However, if the
4592 authenticator set a condition to be tested, we ignore AUTH on MAIL unless
4593 the condition is met. The value of AUTH is an xtext, which means that +,
4594 = and cntrl chars are coded in hex; however "<>" is unaffected by this
4596 case ENV_MAIL_OPT_AUTH:
4597 if (Ustrcmp(value, "<>") != 0)
4602 if (auth_xtextdecode(value, &authenticated_sender) < 0)
4604 /* Put back terminator overrides for error message */
4607 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4608 US"invalid data for AUTH");
4611 if (!acl_smtp_mailauth)
4613 ignore_msg = US"client not authenticated";
4614 rc = sender_host_authenticated ? OK : FAIL;
4618 ignore_msg = US"rejected by ACL";
4619 rc = acl_check(ACL_WHERE_MAILAUTH, NULL, acl_smtp_mailauth,
4620 &user_msg, &log_msg);
4626 if (authenticated_by == NULL ||
4627 authenticated_by->mail_auth_condition == NULL ||
4628 expand_check_condition(authenticated_by->mail_auth_condition,
4629 authenticated_by->name, US"authenticator"))
4630 break; /* Accept the AUTH */
4632 ignore_msg = US"server_mail_auth_condition failed";
4633 if (authenticated_id != NULL)
4634 ignore_msg = string_sprintf("%s: authenticated ID=\"%s\"",
4635 ignore_msg, authenticated_id);
4640 authenticated_sender = NULL;
4641 log_write(0, LOG_MAIN, "ignoring AUTH=%s from %s (%s)",
4642 value, host_and_ident(TRUE), ignore_msg);
4645 /* Should only get DEFER or ERROR here. Put back terminator
4646 overrides for error message */
4651 (void)smtp_handle_acl_fail(ACL_WHERE_MAILAUTH, rc, user_msg,
4658 #ifndef DISABLE_PRDR
4659 case ENV_MAIL_OPT_PRDR:
4661 prdr_requested = TRUE;
4666 case ENV_MAIL_OPT_UTF8:
4667 if (smtputf8_advertised)
4669 int old_pool = store_pool;
4671 DEBUG(D_receive) debug_printf("smtputf8 requested\n");
4672 message_smtputf8 = allow_utf8_domains = TRUE;
4673 store_pool = POOL_PERM;
4674 received_protocol = string_sprintf("utf8%s", received_protocol);
4675 store_pool = old_pool;
4679 /* No valid option. Stick back the terminator characters and break
4680 the loop. Do the name-terminator second as extract_option sets
4681 value==name when it found no equal-sign.
4682 An error for a malformed address will occur. */
4683 case ENV_MAIL_OPT_NULL:
4691 /* Break out of for loop if switch() had bad argument or
4692 when start of the email address is reached */
4693 if (arg_error) break;
4696 /* If we have passed the threshold for rate limiting, apply the current
4697 delay, and update it for next time, provided this is a limited host. */
4699 if (smtp_mailcmd_count > smtp_rlm_threshold &&
4700 verify_check_host(&smtp_ratelimit_hosts) == OK)
4702 DEBUG(D_receive) debug_printf("rate limit MAIL: delay %.3g sec\n",
4703 smtp_delay_mail/1000.0);
4704 millisleep((int)smtp_delay_mail);
4705 smtp_delay_mail *= smtp_rlm_factor;
4706 if (smtp_delay_mail > (double)smtp_rlm_limit)
4707 smtp_delay_mail = (double)smtp_rlm_limit;
4710 /* Now extract the address, first applying any SMTP-time rewriting. The
4711 TRUE flag allows "<>" as a sender address. */
4713 raw_sender = rewrite_existflags & rewrite_smtp
4714 ? rewrite_one(smtp_cmd_data, rewrite_smtp, NULL, FALSE, US"",
4715 global_rewrite_rules)
4719 parse_extract_address(raw_sender, &errmess, &start, &end, &sender_domain,
4724 done = synprot_error(L_smtp_syntax_error, 501, smtp_cmd_data, errmess);
4728 sender_address = raw_sender;
4730 /* If there is a configured size limit for mail, check that this message
4731 doesn't exceed it. The check is postponed to this point so that the sender
4734 if (thismessage_size_limit > 0 && message_size > thismessage_size_limit)
4736 smtp_printf("552 Message size exceeds maximum permitted\r\n", FALSE);
4737 log_write(L_size_reject,
4738 LOG_MAIN|LOG_REJECT, "rejected MAIL FROM:<%s> %s: "
4739 "message too big: size%s=%d max=%d",
4741 host_and_ident(TRUE),
4742 (message_size == INT_MAX)? ">" : "",
4744 thismessage_size_limit);
4745 sender_address = NULL;
4749 /* Check there is enough space on the disk unless configured not to.
4750 When smtp_check_spool_space is set, the check is for thismessage_size_limit
4751 plus the current message - i.e. we accept the message only if it won't
4752 reduce the space below the threshold. Add 5000 to the size to allow for
4753 overheads such as the Received: line and storing of recipients, etc.
4754 By putting the check here, even when SIZE is not given, it allow VRFY
4755 and EXPN etc. to be used when space is short. */
4757 if (!receive_check_fs(
4758 (smtp_check_spool_space && message_size >= 0)?
4759 message_size + 5000 : 0))
4761 smtp_printf("452 Space shortage, please try later\r\n", FALSE);
4762 sender_address = NULL;
4766 /* If sender_address is unqualified, reject it, unless this is a locally
4767 generated message, or the sending host or net is permitted to send
4768 unqualified addresses - typically local machines behaving as MUAs -
4769 in which case just qualify the address. The flag is set above at the start
4770 of the SMTP connection. */
4772 if (sender_domain == 0 && sender_address[0] != 0)
4774 if (allow_unqualified_sender)
4776 sender_domain = Ustrlen(sender_address) + 1;
4777 sender_address = rewrite_address_qualify(sender_address, FALSE);
4778 DEBUG(D_receive) debug_printf("unqualified address %s accepted\n",
4783 smtp_printf("501 %s: sender address must contain a domain\r\n", FALSE,
4785 log_write(L_smtp_syntax_error,
4786 LOG_MAIN|LOG_REJECT,
4787 "unqualified sender rejected: <%s> %s%s",
4789 host_and_ident(TRUE),
4791 sender_address = NULL;
4796 /* Apply an ACL check if one is defined, before responding. Afterwards,
4797 when pipelining is not advertised, do another sync check in case the ACL
4798 delayed and the client started sending in the meantime. */
4802 rc = acl_check(ACL_WHERE_MAIL, NULL, acl_smtp_mail, &user_msg, &log_msg);
4803 if (rc == OK && !pipelining_advertised && !check_sync())
4809 if (rc == OK || rc == DISCARD)
4811 BOOL more = pipeline_response();
4814 smtp_printf("%s%s%s", more, US"250 OK",
4815 #ifndef DISABLE_PRDR
4816 prdr_requested ? US", PRDR Requested" : US"",
4823 #ifndef DISABLE_PRDR
4825 user_msg = string_sprintf("%s%s", user_msg, US", PRDR Requested");
4827 smtp_user_msg(US"250", user_msg);
4829 smtp_delay_rcpt = smtp_rlr_base;
4830 recipients_discarded = (rc == DISCARD);
4831 was_rej_mail = FALSE;
4835 done = smtp_handle_acl_fail(ACL_WHERE_MAIL, rc, user_msg, log_msg);
4836 sender_address = NULL;
4841 /* The RCPT command requires an address as an operand. There may be any
4842 number of RCPT commands, specifying multiple recipients. We build them all
4843 into a data structure. The start/end values given by parse_extract_address
4844 are not used, as we keep only the extracted address. */
4849 was_rcpt = rcpt_in_progress = TRUE;
4851 /* There must be a sender address; if the sender was rejected and
4852 pipelining was advertised, we assume the client was pipelining, and do not
4853 count this as a protocol error. Reset was_rej_mail so that further RCPTs
4854 get the same treatment. */
4856 if (sender_address == NULL)
4858 if (pipelining_advertised && last_was_rej_mail)
4860 smtp_printf("503 sender not yet given\r\n", FALSE);
4861 was_rej_mail = TRUE;
4865 done = synprot_error(L_smtp_protocol_error, 503, NULL,
4866 US"sender not yet given");
4867 was_rcpt = FALSE; /* Not a valid RCPT */
4873 /* Check for an operand */
4875 if (smtp_cmd_data[0] == 0)
4877 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4878 US"RCPT must have an address operand");
4883 /* Set the DSN flags orcpt and dsn_flags from the session*/
4889 uschar *name, *value;
4891 if (!extract_option(&name, &value))
4894 if (dsn_advertised && strcmpic(name, US"ORCPT") == 0)
4896 /* Check whether orcpt has been already set */
4899 synprot_error(L_smtp_syntax_error, 501, NULL,
4900 US"ORCPT can be specified once only");
4903 orcpt = string_copy(value);
4904 DEBUG(D_receive) debug_printf("DSN orcpt: %s\n", orcpt);
4907 else if (dsn_advertised && strcmpic(name, US"NOTIFY") == 0)
4909 /* Check if the notify flags have been already set */
4912 synprot_error(L_smtp_syntax_error, 501, NULL,
4913 US"NOTIFY can be specified once only");
4916 if (strcmpic(value, US"NEVER") == 0)
4917 flags |= rf_notify_never;
4924 while (*pp != 0 && *pp != ',') pp++;
4925 if (*pp == ',') *pp++ = 0;
4926 if (strcmpic(p, US"SUCCESS") == 0)
4928 DEBUG(D_receive) debug_printf("DSN: Setting notify success\n");
4929 flags |= rf_notify_success;
4931 else if (strcmpic(p, US"FAILURE") == 0)
4933 DEBUG(D_receive) debug_printf("DSN: Setting notify failure\n");
4934 flags |= rf_notify_failure;
4936 else if (strcmpic(p, US"DELAY") == 0)
4938 DEBUG(D_receive) debug_printf("DSN: Setting notify delay\n");
4939 flags |= rf_notify_delay;
4943 /* Catch any strange values */
4944 synprot_error(L_smtp_syntax_error, 501, NULL,
4945 US"Invalid value for NOTIFY parameter");
4950 DEBUG(D_receive) debug_printf("DSN Flags: %x\n", flags);
4954 /* Unknown option. Stick back the terminator characters and break
4955 the loop. An error for a malformed address will occur. */
4959 DEBUG(D_receive) debug_printf("Invalid RCPT option: %s : %s\n", name, value);
4966 /* Apply SMTP rewriting then extract the working address. Don't allow "<>"
4967 as a recipient address */
4969 recipient = rewrite_existflags & rewrite_smtp
4970 ? rewrite_one(smtp_cmd_data, rewrite_smtp, NULL, FALSE, US"",
4971 global_rewrite_rules)
4974 if (!(recipient = parse_extract_address(recipient, &errmess, &start, &end,
4975 &recipient_domain, FALSE)))
4977 done = synprot_error(L_smtp_syntax_error, 501, smtp_cmd_data, errmess);
4982 /* If the recipient address is unqualified, reject it, unless this is a
4983 locally generated message. However, unqualified addresses are permitted
4984 from a configured list of hosts and nets - typically when behaving as
4985 MUAs rather than MTAs. Sad that SMTP is used for both types of traffic,
4986 really. The flag is set at the start of the SMTP connection.
4988 RFC 1123 talks about supporting "the reserved mailbox postmaster"; I always
4989 assumed this meant "reserved local part", but the revision of RFC 821 and
4990 friends now makes it absolutely clear that it means *mailbox*. Consequently
4991 we must always qualify this address, regardless. */
4993 if (!recipient_domain)
4994 if (!(recipient_domain = qualify_recipient(&recipient, smtp_cmd_data,
5001 /* Check maximum allowed */
5003 if (rcpt_count > recipients_max && recipients_max > 0)
5005 if (recipients_max_reject)
5008 smtp_printf("552 too many recipients\r\n", FALSE);
5010 log_write(0, LOG_MAIN|LOG_REJECT, "too many recipients: message "
5011 "rejected: sender=<%s> %s", sender_address, host_and_ident(TRUE));
5016 smtp_printf("452 too many recipients\r\n", FALSE);
5018 log_write(0, LOG_MAIN|LOG_REJECT, "too many recipients: excess "
5019 "temporarily rejected: sender=<%s> %s", sender_address,
5020 host_and_ident(TRUE));
5027 /* If we have passed the threshold for rate limiting, apply the current
5028 delay, and update it for next time, provided this is a limited host. */
5030 if (rcpt_count > smtp_rlr_threshold &&
5031 verify_check_host(&smtp_ratelimit_hosts) == OK)
5033 DEBUG(D_receive) debug_printf("rate limit RCPT: delay %.3g sec\n",
5034 smtp_delay_rcpt/1000.0);
5035 millisleep((int)smtp_delay_rcpt);
5036 smtp_delay_rcpt *= smtp_rlr_factor;
5037 if (smtp_delay_rcpt > (double)smtp_rlr_limit)
5038 smtp_delay_rcpt = (double)smtp_rlr_limit;
5041 /* If the MAIL ACL discarded all the recipients, we bypass ACL checking
5042 for them. Otherwise, check the access control list for this recipient. As
5043 there may be a delay in this, re-check for a synchronization error
5044 afterwards, unless pipelining was advertised. */
5046 if (recipients_discarded)
5049 if ( (rc = acl_check(ACL_WHERE_RCPT, recipient, acl_smtp_rcpt, &user_msg,
5051 && !pipelining_advertised && !check_sync())
5054 /* The ACL was happy */
5058 BOOL more = pipeline_response();
5061 smtp_user_msg(US"250", user_msg);
5063 smtp_printf("250 Accepted\r\n", more);
5064 receive_add_recipient(recipient, -1);
5066 /* Set the dsn flags in the recipients_list */
5067 recipients_list[recipients_count-1].orcpt = orcpt;
5068 recipients_list[recipients_count-1].dsn_flags = flags;
5070 DEBUG(D_receive) debug_printf("DSN: orcpt: %s flags: %d\n",
5071 recipients_list[recipients_count-1].orcpt,
5072 recipients_list[recipients_count-1].dsn_flags);
5075 /* The recipient was discarded */
5077 else if (rc == DISCARD)
5080 smtp_user_msg(US"250", user_msg);
5082 smtp_printf("250 Accepted\r\n", FALSE);
5085 log_write(0, LOG_MAIN|LOG_REJECT, "%s F=<%s> RCPT %s: "
5086 "discarded by %s ACL%s%s", host_and_ident(TRUE),
5087 sender_address_unrewritten? sender_address_unrewritten : sender_address,
5088 smtp_cmd_argument, recipients_discarded? "MAIL" : "RCPT",
5089 log_msg ? US": " : US"", log_msg ? log_msg : US"");
5092 /* Either the ACL failed the address, or it was deferred. */
5096 if (rc == FAIL) rcpt_fail_count++; else rcpt_defer_count++;
5097 done = smtp_handle_acl_fail(ACL_WHERE_RCPT, rc, user_msg, log_msg);
5102 /* The DATA command is legal only if it follows successful MAIL FROM
5103 and RCPT TO commands. However, if pipelining is advertised, a bad DATA is
5104 not counted as a protocol error if it follows RCPT (which must have been
5105 rejected if there are no recipients.) This function is complete when a
5106 valid DATA command is encountered.
5108 Note concerning the code used: RFC 2821 says this:
5110 - If there was no MAIL, or no RCPT, command, or all such commands
5111 were rejected, the server MAY return a "command out of sequence"
5112 (503) or "no valid recipients" (554) reply in response to the
5115 The example in the pipelining RFC 2920 uses 554, but I use 503 here
5116 because it is the same whether pipelining is in use or not.
5118 If all the RCPT commands that precede DATA provoked the same error message
5119 (often indicating some kind of system error), it is helpful to include it
5120 with the DATA rejection (an idea suggested by Tony Finch). */
5127 if (chunking_state != CHUNKING_OFFERED)
5129 done = synprot_error(L_smtp_protocol_error, 503, NULL,
5130 US"BDAT command used when CHUNKING not advertised");
5134 /* grab size, endmarker */
5136 if (sscanf(CS smtp_cmd_data, "%u %n", &chunking_datasize, &n) < 1)
5138 done = synprot_error(L_smtp_protocol_error, 501, NULL,
5139 US"missing size for BDAT command");
5142 chunking_state = strcmpic(smtp_cmd_data+n, US"LAST") == 0
5143 ? CHUNKING_LAST : CHUNKING_ACTIVE;
5144 chunking_data_left = chunking_datasize;
5145 DEBUG(D_receive) debug_printf("chunking state %d, %d bytes\n",
5146 (int)chunking_state, chunking_data_left);
5148 /* push the current receive_* function on the "stack", and
5149 replace them by bdat_getc(), which in turn will use the lwr_receive_*
5150 functions to do the dirty work. */
5151 lwr_receive_getc = receive_getc;
5152 lwr_receive_getbuf = receive_getbuf;
5153 lwr_receive_ungetc = receive_ungetc;
5155 receive_getc = bdat_getc;
5156 receive_ungetc = bdat_ungetc;
5167 DATA_BDAT: /* Common code for DATA and BDAT */
5168 if (!discarded && recipients_count <= 0)
5170 if (rcpt_smtp_response_same && rcpt_smtp_response != NULL)
5172 uschar *code = US"503";
5173 int len = Ustrlen(rcpt_smtp_response);
5174 smtp_respond(code, 3, FALSE, US"All RCPT commands were rejected with "
5176 /* Responses from smtp_printf() will have \r\n on the end */
5177 if (len > 2 && rcpt_smtp_response[len-2] == '\r')
5178 rcpt_smtp_response[len-2] = 0;
5179 smtp_respond(code, 3, FALSE, rcpt_smtp_response);
5181 if (pipelining_advertised && last_was_rcpt)
5182 smtp_printf("503 Valid RCPT command must precede %s\r\n", FALSE,
5183 smtp_names[smtp_connection_had[smtp_ch_index-1]]);
5185 done = synprot_error(L_smtp_protocol_error, 503, NULL,
5186 smtp_connection_had[smtp_ch_index-1] == SCH_DATA
5187 ? US"valid RCPT command must precede DATA"
5188 : US"valid RCPT command must precede BDAT");
5190 if (chunking_state > CHUNKING_OFFERED)
5195 if (toomany && recipients_max_reject)
5197 sender_address = NULL; /* This will allow a new MAIL without RSET */
5198 sender_address_unrewritten = NULL;
5199 smtp_printf("554 Too many recipients\r\n", FALSE);
5203 if (chunking_state > CHUNKING_OFFERED)
5204 rc = OK; /* No predata ACL or go-ahead output for BDAT */
5207 /* If there is an ACL, re-check the synchronization afterwards, since the
5208 ACL may have delayed. To handle cutthrough delivery enforce a dummy call
5209 to get the DATA command sent. */
5211 if (acl_smtp_predata == NULL && cutthrough.fd < 0)
5215 uschar * acl = acl_smtp_predata ? acl_smtp_predata : US"accept";
5216 enable_dollar_recipients = TRUE;
5217 rc = acl_check(ACL_WHERE_PREDATA, NULL, acl, &user_msg,
5219 enable_dollar_recipients = FALSE;
5220 if (rc == OK && !check_sync())
5224 { /* Either the ACL failed the address, or it was deferred. */
5225 done = smtp_handle_acl_fail(ACL_WHERE_PREDATA, rc, user_msg, log_msg);
5231 smtp_user_msg(US"354", user_msg);
5234 "354 Enter message, ending with \".\" on a line by itself\r\n", FALSE);
5238 if (smtp_in) /* all ACKs needed to ramp window up for bulk data */
5239 (void) setsockopt(fileno(smtp_in), IPPROTO_TCP, TCP_QUICKACK,
5240 US &on, sizeof(on));
5243 message_ended = END_NOTENDED; /* Indicate in middle of data */
5254 if (!(address = parse_extract_address(smtp_cmd_data, &errmess,
5255 &start, &end, &recipient_domain, FALSE)))
5257 smtp_printf("501 %s\r\n", FALSE, errmess);
5261 if (!recipient_domain)
5262 if (!(recipient_domain = qualify_recipient(&address, smtp_cmd_data,
5266 if ((rc = acl_check(ACL_WHERE_VRFY, address, acl_smtp_vrfy,
5267 &user_msg, &log_msg)) != OK)
5268 done = smtp_handle_acl_fail(ACL_WHERE_VRFY, rc, user_msg, log_msg);
5272 address_item * addr = deliver_make_addr(address, FALSE);
5274 switch(verify_address(addr, NULL, vopt_is_recipient | vopt_qualify, -1,
5275 -1, -1, NULL, NULL, NULL))
5278 s = string_sprintf("250 <%s> is deliverable", address);
5282 s = (addr->user_message != NULL)?
5283 string_sprintf("451 <%s> %s", address, addr->user_message) :
5284 string_sprintf("451 Cannot resolve <%s> at this time", address);
5288 s = (addr->user_message != NULL)?
5289 string_sprintf("550 <%s> %s", address, addr->user_message) :
5290 string_sprintf("550 <%s> is not deliverable", address);
5291 log_write(0, LOG_MAIN, "VRFY failed for %s %s",
5292 smtp_cmd_argument, host_and_ident(TRUE));
5296 smtp_printf("%s\r\n", FALSE, s);
5304 rc = acl_check(ACL_WHERE_EXPN, NULL, acl_smtp_expn, &user_msg, &log_msg);
5306 done = smtp_handle_acl_fail(ACL_WHERE_EXPN, rc, user_msg, log_msg);
5309 BOOL save_log_testing_mode = log_testing_mode;
5310 address_test_mode = log_testing_mode = TRUE;
5311 (void) verify_address(deliver_make_addr(smtp_cmd_data, FALSE),
5312 smtp_out, vopt_is_recipient | vopt_qualify | vopt_expn, -1, -1, -1,
5314 address_test_mode = FALSE;
5315 log_testing_mode = save_log_testing_mode; /* true for -bh */
5324 if (!tls_advertised)
5326 done = synprot_error(L_smtp_protocol_error, 503, NULL,
5327 US"STARTTLS command used when not advertised");
5331 /* Apply an ACL check if one is defined */
5333 if ( acl_smtp_starttls
5334 && (rc = acl_check(ACL_WHERE_STARTTLS, NULL, acl_smtp_starttls,
5335 &user_msg, &log_msg)) != OK
5338 done = smtp_handle_acl_fail(ACL_WHERE_STARTTLS, rc, user_msg, log_msg);
5342 /* RFC 2487 is not clear on when this command may be sent, though it
5343 does state that all information previously obtained from the client
5344 must be discarded if a TLS session is started. It seems reasonable to
5345 do an implied RSET when STARTTLS is received. */
5347 incomplete_transaction_log(US"STARTTLS");
5348 cancel_cutthrough_connection(TRUE, US"STARTTLS received");
5349 smtp_reset(reset_point);
5351 cmd_list[CMD_LIST_STARTTLS].is_mail_cmd = FALSE;
5353 /* There's an attack where more data is read in past the STARTTLS command
5354 before TLS is negotiated, then assumed to be part of the secure session
5355 when used afterwards; we use segregated input buffers, so are not
5356 vulnerable, but we want to note when it happens and, for sheer paranoia,
5357 ensure that the buffer is "wiped".
5358 Pipelining sync checks will normally have protected us too, unless disabled
5359 by configuration. */
5361 if (receive_smtp_buffered())
5364 debug_printf("Non-empty input buffer after STARTTLS; naive attack?\n");
5365 if (tls_in.active < 0)
5366 smtp_inend = smtp_inptr = smtp_inbuffer;
5367 /* and if TLS is already active, tls_server_start() should fail */
5370 /* There is nothing we value in the input buffer and if TLS is successfully
5371 negotiated, we won't use this buffer again; if TLS fails, we'll just read
5372 fresh content into it. The buffer contains arbitrary content from an
5373 untrusted remote source; eg: NOOP <shellcode>\r\nSTARTTLS\r\n
5374 It seems safest to just wipe away the content rather than leave it as a
5375 target to jump to. */
5377 memset(smtp_inbuffer, 0, IN_BUFFER_SIZE);
5379 /* Attempt to start up a TLS session, and if successful, discard all
5380 knowledge that was obtained previously. At least, that's what the RFC says,
5381 and that's what happens by default. However, in order to work round YAEB,
5382 there is an option to remember the esmtp state. Sigh.
5384 We must allow for an extra EHLO command and an extra AUTH command after
5385 STARTTLS that don't add to the nonmail command count. */
5388 if ((rc = tls_server_start(tls_require_ciphers, &s)) == OK)
5390 if (!tls_remember_esmtp)
5391 helo_seen = esmtp = auth_advertised = pipelining_advertised = FALSE;
5392 cmd_list[CMD_LIST_EHLO].is_mail_cmd = TRUE;
5393 cmd_list[CMD_LIST_AUTH].is_mail_cmd = TRUE;
5394 cmd_list[CMD_LIST_TLS_AUTH].is_mail_cmd = TRUE;
5395 if (sender_helo_name)
5397 store_free(sender_helo_name);
5398 sender_helo_name = NULL;
5399 host_build_sender_fullhost(); /* Rebuild */
5400 set_process_info("handling incoming TLS connection from %s",
5401 host_and_ident(FALSE));
5404 (sender_host_address ? protocols : protocols_local)
5406 ? pextend + (sender_host_authenticated ? pauthed : 0)
5408 + (tls_in.active >= 0 ? pcrpted : 0)
5411 sender_host_auth_pubname = sender_host_authenticated = NULL;
5412 authenticated_id = NULL;
5413 sync_cmd_limit = NON_SYNC_CMD_NON_PIPELINING;
5414 DEBUG(D_tls) debug_printf("TLS active\n");
5415 break; /* Successful STARTTLS */
5418 (void) smtp_log_tls_fail(s);
5420 /* Some local configuration problem was discovered before actually trying
5421 to do a TLS handshake; give a temporary error. */
5425 smtp_printf("454 TLS currently unavailable\r\n", FALSE);
5429 /* Hard failure. Reject everything except QUIT or closed connection. One
5430 cause for failure is a nested STARTTLS, in which case tls_in.active remains
5431 set, but we must still reject all incoming commands. */
5433 DEBUG(D_tls) debug_printf("TLS failed to start\n");
5434 while (done <= 0) switch(smtp_read_command(FALSE, GETC_BUFFER_UNLIMITED))
5437 log_write(L_smtp_connection, LOG_MAIN, "%s closed by EOF",
5438 smtp_get_connection_info());
5439 smtp_notquit_exit(US"tls-failed", NULL, NULL);
5443 /* It is perhaps arguable as to which exit ACL should be called here,
5444 but as it is probably a situation that almost never arises, it
5445 probably doesn't matter. We choose to call the real QUIT ACL, which in
5446 some sense is perhaps "right". */
5451 && ((rc = acl_check(ACL_WHERE_QUIT, NULL, acl_smtp_quit, &user_msg,
5452 &log_msg)) == ERROR))
5453 log_write(0, LOG_MAIN|LOG_PANIC, "ACL for QUIT returned ERROR: %s",
5456 smtp_respond(US"221", 3, TRUE, user_msg);
5458 smtp_printf("221 %s closing connection\r\n", FALSE, smtp_active_hostname);
5459 log_write(L_smtp_connection, LOG_MAIN, "%s closed by QUIT",
5460 smtp_get_connection_info());
5465 smtp_printf("554 Security failure\r\n", FALSE);
5468 tls_close(TRUE, TLS_SHUTDOWN_NOWAIT);
5473 /* The ACL for QUIT is provided for gathering statistical information or
5474 similar; it does not affect the response code, but it can supply a custom
5478 smtp_quit_handler(&user_msg, &log_msg);
5484 smtp_rset_handler();
5485 cancel_cutthrough_connection(TRUE, US"RSET received");
5486 smtp_reset(reset_point);
5493 smtp_printf("250 OK\r\n", FALSE);
5497 /* Show ETRN/EXPN/VRFY if there's an ACL for checking hosts; if actually
5498 used, a check will be done for permitted hosts. Show STARTTLS only if not
5499 already in a TLS session and if it would be advertised in the EHLO
5504 smtp_printf("214-Commands supported:\r\n", TRUE);
5508 Ustrcat(buffer, " AUTH");
5510 if (tls_in.active < 0 &&
5511 verify_check_host(&tls_advertise_hosts) != FAIL)
5512 Ustrcat(buffer, " STARTTLS");
5514 Ustrcat(buffer, " HELO EHLO MAIL RCPT DATA BDAT");
5515 Ustrcat(buffer, " NOOP QUIT RSET HELP");
5516 if (acl_smtp_etrn != NULL) Ustrcat(buffer, " ETRN");
5517 if (acl_smtp_expn != NULL) Ustrcat(buffer, " EXPN");
5518 if (acl_smtp_vrfy != NULL) Ustrcat(buffer, " VRFY");
5519 smtp_printf("214%s\r\n", FALSE, buffer);
5525 incomplete_transaction_log(US"connection lost");
5526 smtp_notquit_exit(US"connection-lost", US"421",
5527 US"%s lost input connection", smtp_active_hostname);
5529 /* Don't log by default unless in the middle of a message, as some mailers
5530 just drop the call rather than sending QUIT, and it clutters up the logs.
5533 if (sender_address || recipients_count > 0)
5534 log_write(L_lost_incoming_connection, LOG_MAIN,
5535 "unexpected %s while reading SMTP command from %s%s%s D=%s",
5536 sender_host_unknown ? "EOF" : "disconnection",
5537 tcp_in_fastopen && !tcp_in_fastopen_logged ? US"TFO " : US"",
5538 host_and_ident(FALSE), smtp_read_error,
5539 string_timesince(&smtp_connection_start)
5543 log_write(L_smtp_connection, LOG_MAIN, "%s %slost%s D=%s",
5544 smtp_get_connection_info(),
5545 tcp_in_fastopen && !tcp_in_fastopen_logged ? US"TFO " : US"",
5547 string_timesince(&smtp_connection_start)
5558 done = synprot_error(L_smtp_protocol_error, 503, NULL,
5559 US"ETRN is not permitted inside a transaction");
5563 log_write(L_etrn, LOG_MAIN, "ETRN %s received from %s", smtp_cmd_argument,
5564 host_and_ident(FALSE));
5566 if ((rc = acl_check(ACL_WHERE_ETRN, NULL, acl_smtp_etrn,
5567 &user_msg, &log_msg)) != OK)
5569 done = smtp_handle_acl_fail(ACL_WHERE_ETRN, rc, user_msg, log_msg);
5573 /* Compute the serialization key for this command. */
5575 etrn_serialize_key = string_sprintf("etrn-%s\n", smtp_cmd_data);
5577 /* If a command has been specified for running as a result of ETRN, we
5578 permit any argument to ETRN. If not, only the # standard form is permitted,
5579 since that is strictly the only kind of ETRN that can be implemented
5580 according to the RFC. */
5582 if (smtp_etrn_command)
5586 etrn_command = smtp_etrn_command;
5587 deliver_domain = smtp_cmd_data;
5588 rc = transport_set_up_command(&argv, smtp_etrn_command, TRUE, 0, NULL,
5589 US"ETRN processing", &error);
5590 deliver_domain = NULL;
5593 log_write(0, LOG_MAIN|LOG_PANIC, "failed to set up ETRN command: %s",
5595 smtp_printf("458 Internal failure\r\n", FALSE);
5600 /* Else set up to call Exim with the -R option. */
5604 if (*smtp_cmd_data++ != '#')
5606 done = synprot_error(L_smtp_syntax_error, 501, NULL,
5607 US"argument must begin with #");
5610 etrn_command = US"exim -R";
5611 argv = CUSS child_exec_exim(CEE_RETURN_ARGV, TRUE, NULL, TRUE,
5612 *queue_name ? 4 : 2,
5613 US"-R", smtp_cmd_data,
5614 US"-MCG", queue_name);
5617 /* If we are host-testing, don't actually do anything. */
5623 debug_printf("ETRN command is: %s\n", etrn_command);
5624 debug_printf("ETRN command execution skipped\n");
5626 if (user_msg == NULL) smtp_printf("250 OK\r\n", FALSE);
5627 else smtp_user_msg(US"250", user_msg);
5632 /* If ETRN queue runs are to be serialized, check the database to
5633 ensure one isn't already running. */
5635 if (smtp_etrn_serialize && !enq_start(etrn_serialize_key, 1))
5637 smtp_printf("458 Already processing %s\r\n", FALSE, smtp_cmd_data);
5641 /* Fork a child process and run the command. We don't want to have to
5642 wait for the process at any point, so set SIGCHLD to SIG_IGN before
5643 forking. It should be set that way anyway for external incoming SMTP,
5644 but we save and restore to be tidy. If serialization is required, we
5645 actually run the command in yet another process, so we can wait for it
5646 to complete and then remove the serialization lock. */
5648 oldsignal = signal(SIGCHLD, SIG_IGN);
5650 if ((pid = fork()) == 0)
5652 smtp_input = FALSE; /* This process is not associated with the */
5653 (void)fclose(smtp_in); /* SMTP call any more. */
5654 (void)fclose(smtp_out);
5656 signal(SIGCHLD, SIG_DFL); /* Want to catch child */
5658 /* If not serializing, do the exec right away. Otherwise, fork down
5659 into another process. */
5661 if (!smtp_etrn_serialize || (pid = fork()) == 0)
5663 DEBUG(D_exec) debug_print_argv(argv);
5664 exim_nullstd(); /* Ensure std{in,out,err} exist */
5665 execv(CS argv[0], (char *const *)argv);
5666 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "exec of \"%s\" (ETRN) failed: %s",
5667 etrn_command, strerror(errno));
5668 _exit(EXIT_FAILURE); /* paranoia */
5671 /* Obey this if smtp_serialize and the 2nd fork yielded non-zero. That
5672 is, we are in the first subprocess, after forking again. All we can do
5673 for a failing fork is to log it. Otherwise, wait for the 2nd process to
5674 complete, before removing the serialization. */
5677 log_write(0, LOG_MAIN|LOG_PANIC, "2nd fork for serialized ETRN "
5678 "failed: %s", strerror(errno));
5682 DEBUG(D_any) debug_printf("waiting for serialized ETRN process %d\n",
5684 (void)wait(&status);
5685 DEBUG(D_any) debug_printf("serialized ETRN process %d ended\n",
5689 enq_end(etrn_serialize_key);
5690 _exit(EXIT_SUCCESS);
5693 /* Back in the top level SMTP process. Check that we started a subprocess
5694 and restore the signal state. */
5698 log_write(0, LOG_MAIN|LOG_PANIC, "fork of process for ETRN failed: %s",
5700 smtp_printf("458 Unable to fork process\r\n", FALSE);
5701 if (smtp_etrn_serialize) enq_end(etrn_serialize_key);
5705 if (user_msg == NULL) smtp_printf("250 OK\r\n", FALSE);
5706 else smtp_user_msg(US"250", user_msg);
5709 signal(SIGCHLD, oldsignal);
5714 done = synprot_error(L_smtp_syntax_error, 501, NULL,
5715 US"unexpected argument data");
5719 /* This currently happens only for NULLs, but could be extended. */
5722 done = synprot_error(L_smtp_syntax_error, 0, NULL, /* Just logs */
5723 US"NULL character(s) present (shown as '?')");
5724 smtp_printf("501 NULL characters are not allowed in SMTP commands\r\n", FALSE);
5730 if (smtp_inend >= smtp_inbuffer + IN_BUFFER_SIZE)
5731 smtp_inend = smtp_inbuffer + IN_BUFFER_SIZE - 1;
5732 c = smtp_inend - smtp_inptr;
5733 if (c > 150) c = 150;
5735 incomplete_transaction_log(US"sync failure");
5736 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP protocol synchronization error "
5737 "(next input sent too soon: pipelining was%s advertised): "
5738 "rejected \"%s\" %s next input=\"%s\"",
5739 pipelining_advertised? "" : " not",
5740 smtp_cmd_buffer, host_and_ident(TRUE),
5741 string_printing(smtp_inptr));
5742 smtp_notquit_exit(US"synchronization-error", US"554",
5743 US"SMTP synchronization error");
5744 done = 1; /* Pretend eof - drops connection */
5748 case TOO_MANY_NONMAIL_CMD:
5749 s = smtp_cmd_buffer;
5750 while (*s != 0 && !isspace(*s)) s++;
5751 incomplete_transaction_log(US"too many non-mail commands");
5752 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
5753 "nonmail commands (last was \"%.*s\")", host_and_ident(FALSE),
5754 (int)(s - smtp_cmd_buffer), smtp_cmd_buffer);
5755 smtp_notquit_exit(US"bad-commands", US"554", US"Too many nonmail commands");
5756 done = 1; /* Pretend eof - drops connection */
5759 #ifdef SUPPORT_PROXY
5760 case PROXY_FAIL_IGNORE_CMD:
5761 smtp_printf("503 Command refused, required Proxy negotiation failed\r\n", FALSE);
5766 if (unknown_command_count++ >= smtp_max_unknown_commands)
5768 log_write(L_smtp_syntax_error, LOG_MAIN,
5769 "SMTP syntax error in \"%s\" %s %s",
5770 string_printing(smtp_cmd_buffer), host_and_ident(TRUE),
5771 US"unrecognized command");
5772 incomplete_transaction_log(US"unrecognized command");
5773 smtp_notquit_exit(US"bad-commands", US"500",
5774 US"Too many unrecognized commands");
5776 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
5777 "unrecognized commands (last was \"%s\")", host_and_ident(FALSE),
5778 string_printing(smtp_cmd_buffer));
5781 done = synprot_error(L_smtp_syntax_error, 500, NULL,
5782 US"unrecognized command");
5786 /* This label is used by goto's inside loops that want to break out to
5787 the end of the command-processing loop. */
5790 last_was_rej_mail = was_rej_mail; /* Remember some last commands for */
5791 last_was_rcpt = was_rcpt; /* protocol error handling */
5795 return done - 2; /* Convert yield values */
5801 authres_smtpauth(gstring * g)
5803 if (!sender_host_authenticated)
5806 g = string_append(g, 2, US";\n\tauth=pass (", sender_host_auth_pubname);
5808 if (Ustrcmp(sender_host_auth_pubname, "tls") != 0)
5809 g = string_append(g, 2, US") smtp.auth=", authenticated_id);
5810 else if (authenticated_id)
5811 g = string_append(g, 2, US") x509.auth=", authenticated_id);
5813 g = string_catn(g, US") reason=x509.auth", 17);
5815 if (authenticated_sender)
5816 g = string_append(g, 2, US" smtp.mailfrom=", authenticated_sender);
5824 /* End of smtp_in.c */