1 /*************************************************
2 * Exim - an Internet mail transport agent *
3 *************************************************/
5 /* Copyright (c) University of Cambridge 1995 - 2017 */
6 /* See the file NOTICE for conditions of use and distribution. */
8 /* Functions for handling an incoming SMTP call. */
15 /* Initialize for TCP wrappers if so configured. It appears that the macro
16 HAVE_IPV6 is used in some versions of the tcpd.h header, so we unset it before
17 including that header, and restore its value afterwards. */
19 #ifdef USE_TCP_WRAPPERS
22 #define EXIM_HAVE_IPV6
28 #define HAVE_IPV6 TRUE
31 int allow_severity = LOG_INFO;
32 int deny_severity = LOG_NOTICE;
33 uschar *tcp_wrappers_name;
37 /* Size of buffer for reading SMTP commands. We used to use 512, as defined
38 by RFC 821. However, RFC 1869 specifies that this must be increased for SMTP
39 commands that accept arguments, and this in particular applies to AUTH, where
40 the data can be quite long. More recently this value was 2048 in Exim;
41 however, RFC 4954 (circa 2007) recommends 12288 bytes to handle AUTH. Clients
42 such as Thunderbird will send an AUTH with an initial-response for GSSAPI.
43 The maximum size of a Kerberos ticket under Windows 2003 is 12000 bytes, and
44 we need room to handle large base64-encoded AUTHs for GSSAPI.
47 #define SMTP_CMD_BUFFER_SIZE 16384
49 /* Size of buffer for reading SMTP incoming packets */
51 #define IN_BUFFER_SIZE 8192
53 /* Structure for SMTP command list */
60 short int is_mail_cmd;
63 /* Codes for identifying commands. We order them so that those that come first
64 are those for which synchronization is always required. Checking this can help
68 /* These commands are required to be synchronized, i.e. to be the last in a
69 block of commands when pipelining. */
71 HELO_CMD, EHLO_CMD, DATA_CMD, /* These are listed in the pipelining */
72 VRFY_CMD, EXPN_CMD, NOOP_CMD, /* RFC as requiring synchronization */
73 ETRN_CMD, /* This by analogy with TURN from the RFC */
74 STARTTLS_CMD, /* Required by the STARTTLS RFC */
75 TLS_AUTH_CMD, /* auto-command at start of SSL */
77 /* This is a dummy to identify the non-sync commands when pipelining */
79 NON_SYNC_CMD_PIPELINING,
81 /* These commands need not be synchronized when pipelining */
83 MAIL_CMD, RCPT_CMD, RSET_CMD,
85 /* This is a dummy to identify the non-sync commands when not pipelining */
87 NON_SYNC_CMD_NON_PIPELINING,
89 /* RFC3030 section 2: "After all MAIL and RCPT responses are collected and
90 processed the message is sent using a series of BDAT commands"
91 implies that BDAT should be synchronized. However, we see Google, at least,
92 sending MAIL,RCPT,BDAT-LAST in a single packet, clearly not waiting for
93 processing of the RCPT response(s). We shall do the same, and not require
94 synch for BDAT. Worse, as the chunk may (very likely will) follow the
95 command-header in the same packet we cannot do the usual "is there any
96 follow-on data after the command line" even for non-pipeline mode.
97 So we'll need an explicit check after reading the expected chunk amount
98 when non-pipe, before sending the ACK. */
102 /* I have been unable to find a statement about the use of pipelining
103 with AUTH, so to be on the safe side it is here, though I kind of feel
104 it should be up there with the synchronized commands. */
108 /* I'm not sure about these, but I don't think they matter. */
113 PROXY_FAIL_IGNORE_CMD,
116 /* These are specials that don't correspond to actual commands */
118 EOF_CMD, OTHER_CMD, BADARG_CMD, BADCHAR_CMD, BADSYN_CMD,
119 TOO_MANY_NONMAIL_CMD };
122 /* This is a convenience macro for adding the identity of an SMTP command
123 to the circular buffer that holds a list of the last n received. */
126 smtp_connection_had[smtp_ch_index++] = n; \
127 if (smtp_ch_index >= SMTP_HBUFF_SIZE) smtp_ch_index = 0
130 /*************************************************
131 * Local static variables *
132 *************************************************/
134 static auth_instance *authenticated_by;
135 static BOOL auth_advertised;
137 static BOOL tls_advertised;
139 static BOOL dsn_advertised;
141 static BOOL helo_required = FALSE;
142 static BOOL helo_verify = FALSE;
143 static BOOL helo_seen;
144 static BOOL helo_accept_junk;
145 static BOOL count_nonmail;
146 static BOOL pipelining_advertised;
147 static BOOL rcpt_smtp_response_same;
148 static BOOL rcpt_in_progress;
149 static int nonmail_command_count;
150 static BOOL smtp_exit_function_called = 0;
152 static BOOL smtputf8_advertised;
154 static int synprot_error_count;
155 static int unknown_command_count;
156 static int sync_cmd_limit;
157 static int smtp_write_error = 0;
159 static uschar *rcpt_smtp_response;
160 static uschar *smtp_data_buffer;
161 static uschar *smtp_cmd_data;
163 /* We need to know the position of RSET, HELO, EHLO, AUTH, and STARTTLS. Their
164 final fields of all except AUTH are forced TRUE at the start of a new message
165 setup, to allow one of each between messages that is not counted as a nonmail
166 command. (In fact, only one of HELO/EHLO is not counted.) Also, we have to
167 allow a new EHLO after starting up TLS.
169 AUTH is "falsely" labelled as a mail command initially, so that it doesn't get
170 counted. However, the flag is changed when AUTH is received, so that multiple
171 failing AUTHs will eventually hit the limit. After a successful AUTH, another
172 AUTH is already forbidden. After a TLS session is started, AUTH's flag is again
173 forced TRUE, to allow for the re-authentication that can happen at that point.
175 QUIT is also "falsely" labelled as a mail command so that it doesn't up the
176 count of non-mail commands and possibly provoke an error.
178 tls_auth is a pseudo-command, never expected in input. It is activated
179 on TLS startup and looks for a tls authenticator. */
181 static smtp_cmd_list cmd_list[] = {
182 /* name len cmd has_arg is_mail_cmd */
184 { "rset", sizeof("rset")-1, RSET_CMD, FALSE, FALSE }, /* First */
185 { "helo", sizeof("helo")-1, HELO_CMD, TRUE, FALSE },
186 { "ehlo", sizeof("ehlo")-1, EHLO_CMD, TRUE, FALSE },
187 { "auth", sizeof("auth")-1, AUTH_CMD, TRUE, TRUE },
189 { "starttls", sizeof("starttls")-1, STARTTLS_CMD, FALSE, FALSE },
190 { "tls_auth", 0, TLS_AUTH_CMD, FALSE, TRUE },
193 /* If you change anything above here, also fix the definitions below. */
195 { "mail from:", sizeof("mail from:")-1, MAIL_CMD, TRUE, TRUE },
196 { "rcpt to:", sizeof("rcpt to:")-1, RCPT_CMD, TRUE, TRUE },
197 { "data", sizeof("data")-1, DATA_CMD, FALSE, TRUE },
198 { "bdat", sizeof("bdat")-1, BDAT_CMD, TRUE, TRUE },
199 { "quit", sizeof("quit")-1, QUIT_CMD, FALSE, TRUE },
200 { "noop", sizeof("noop")-1, NOOP_CMD, TRUE, FALSE },
201 { "etrn", sizeof("etrn")-1, ETRN_CMD, TRUE, FALSE },
202 { "vrfy", sizeof("vrfy")-1, VRFY_CMD, TRUE, FALSE },
203 { "expn", sizeof("expn")-1, EXPN_CMD, TRUE, FALSE },
204 { "help", sizeof("help")-1, HELP_CMD, TRUE, FALSE }
207 static smtp_cmd_list *cmd_list_end =
208 cmd_list + sizeof(cmd_list)/sizeof(smtp_cmd_list);
210 #define CMD_LIST_RSET 0
211 #define CMD_LIST_HELO 1
212 #define CMD_LIST_EHLO 2
213 #define CMD_LIST_AUTH 3
214 #define CMD_LIST_STARTTLS 4
215 #define CMD_LIST_TLS_AUTH 5
217 /* This list of names is used for performing the smtp_no_mail logging action.
218 It must be kept in step with the SCH_xxx enumerations. */
220 static uschar *smtp_names[] =
222 US"NONE", US"AUTH", US"DATA", US"BDAT", US"EHLO", US"ETRN", US"EXPN",
223 US"HELO", US"HELP", US"MAIL", US"NOOP", US"QUIT", US"RCPT", US"RSET",
224 US"STARTTLS", US"VRFY" };
226 static uschar *protocols_local[] = {
227 US"local-smtp", /* HELO */
228 US"local-smtps", /* The rare case EHLO->STARTTLS->HELO */
229 US"local-esmtp", /* EHLO */
230 US"local-esmtps", /* EHLO->STARTTLS->EHLO */
231 US"local-esmtpa", /* EHLO->AUTH */
232 US"local-esmtpsa" /* EHLO->STARTTLS->EHLO->AUTH */
234 static uschar *protocols[] = {
236 US"smtps", /* The rare case EHLO->STARTTLS->HELO */
237 US"esmtp", /* EHLO */
238 US"esmtps", /* EHLO->STARTTLS->EHLO */
239 US"esmtpa", /* EHLO->AUTH */
240 US"esmtpsa" /* EHLO->STARTTLS->EHLO->AUTH */
245 #define pcrpted 1 /* added to pextend or pnormal */
246 #define pauthed 2 /* added to pextend */
248 /* Sanity check and validate optional args to MAIL FROM: envelope */
251 ENV_MAIL_OPT_SIZE, ENV_MAIL_OPT_BODY, ENV_MAIL_OPT_AUTH,
255 ENV_MAIL_OPT_RET, ENV_MAIL_OPT_ENVID,
261 uschar * name; /* option requested during MAIL cmd */
262 int value; /* enum type */
263 BOOL need_value; /* TRUE requires value (name=value pair format)
264 FALSE is a singleton */
266 static env_mail_type_t env_mail_type_list[] = {
267 { US"SIZE", ENV_MAIL_OPT_SIZE, TRUE },
268 { US"BODY", ENV_MAIL_OPT_BODY, TRUE },
269 { US"AUTH", ENV_MAIL_OPT_AUTH, TRUE },
271 { US"PRDR", ENV_MAIL_OPT_PRDR, FALSE },
273 { US"RET", ENV_MAIL_OPT_RET, TRUE },
274 { US"ENVID", ENV_MAIL_OPT_ENVID, TRUE },
276 { US"SMTPUTF8",ENV_MAIL_OPT_UTF8, FALSE }, /* rfc6531 */
278 /* keep this the last entry */
279 { US"NULL", ENV_MAIL_OPT_NULL, FALSE },
282 /* When reading SMTP from a remote host, we have to use our own versions of the
283 C input-reading functions, in order to be able to flush the SMTP output only
284 when about to read more data from the socket. This is the only way to get
285 optimal performance when the client is using pipelining. Flushing for every
286 command causes a separate packet and reply packet each time; saving all the
287 responses up (when pipelining) combines them into one packet and one response.
289 For simplicity, these functions are used for *all* SMTP input, not only when
290 receiving over a socket. However, after setting up a secure socket (SSL), input
291 is read via the OpenSSL library, and another set of functions is used instead
294 These functions are set in the receive_getc etc. variables and called with the
295 same interface as the C functions. However, since there can only ever be
296 one incoming SMTP call, we just use a single buffer and flags. There is no need
297 to implement a complicated private FILE-like structure.*/
299 static uschar *smtp_inbuffer;
300 static uschar *smtp_inptr;
301 static uschar *smtp_inend;
302 static int smtp_had_eof;
303 static int smtp_had_error;
306 /* forward declarations */
307 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;
342 if (tls_in.active >= 0 && tls_could_read())
345 if (smtp_inptr < smtp_inend)
348 fd = fileno(smtp_in);
353 rc = select(fd + 1, (SELECT_ARG2_TYPE *)&fds, NULL, NULL, &tzero);
355 if (rc <= 0) return TRUE; /* Not ready to read */
356 rc = smtp_getc(GETC_BUFFER_UNLIMITED);
357 if (rc < 0) return TRUE; /* End of file or error */
360 rc = smtp_inend - smtp_inptr;
361 if (rc > 150) rc = 150;
369 if (!smtp_enforce_sync || sender_host_address == NULL || sender_host_notsocket)
372 return wouldblock_reading();
376 /* If there's input waiting (and we're doing pipelineing) then we can pipeline
377 a reponse with the one following. */
380 pipeline_response(void)
382 if ( !smtp_enforce_sync || !sender_host_address
383 || sender_host_notsocket || !pipelining_advertised)
386 return !wouldblock_reading();
391 /*************************************************
392 * Log incomplete transactions *
393 *************************************************/
395 /* This function is called after a transaction has been aborted by RSET, QUIT,
396 connection drops or other errors. It logs the envelope information received
397 so far in order to preserve address verification attempts.
399 Argument: string to indicate what aborted the transaction
404 incomplete_transaction_log(uschar *what)
406 if (sender_address == NULL || /* No transaction in progress */
407 !LOGGING(smtp_incomplete_transaction))
410 /* Build list of recipients for logging */
412 if (recipients_count > 0)
415 raw_recipients = store_get(recipients_count * sizeof(uschar *));
416 for (i = 0; i < recipients_count; i++)
417 raw_recipients[i] = recipients_list[i].address;
418 raw_recipients_count = recipients_count;
421 log_write(L_smtp_incomplete_transaction, LOG_MAIN|LOG_SENDER|LOG_RECIPIENTS,
422 "%s incomplete transaction (%s)", host_and_ident(TRUE), what);
428 /* Refill the buffer, and notify DKIM verification code.
429 Return false for error or EOF.
433 smtp_refill(unsigned lim)
436 if (!smtp_out) return FALSE;
438 if (smtp_receive_timeout > 0) alarm(smtp_receive_timeout);
440 /* Limit amount read, so non-message data is not fed to DKIM */
442 rc = read(fileno(smtp_in), smtp_inbuffer, MIN(IN_BUFFER_SIZE, lim));
447 /* Must put the error text in fixed store, because this might be during
448 header reading, where it releases unused store above the header. */
451 smtp_had_error = save_errno;
452 smtp_read_error = string_copy_malloc(
453 string_sprintf(" (error: %s)", strerror(save_errno)));
455 else smtp_had_eof = 1;
459 dkim_exim_verify_feed(smtp_inbuffer, rc);
461 smtp_inend = smtp_inbuffer + rc;
462 smtp_inptr = smtp_inbuffer;
466 /*************************************************
467 * SMTP version of getc() *
468 *************************************************/
470 /* This gets the next byte from the SMTP input buffer. If the buffer is empty,
471 it flushes the output, and refills the buffer, with a timeout. The signal
472 handler is set appropriately by the calling function. This function is not used
473 after a connection has negotiated itself into an TLS/SSL state.
475 Arguments: lim Maximum amount to read/buffer
476 Returns: the next character or EOF
480 smtp_getc(unsigned lim)
482 if (smtp_inptr >= smtp_inend)
483 if (!smtp_refill(lim))
485 return *smtp_inptr++;
489 smtp_getbuf(unsigned * len)
494 if (smtp_inptr >= smtp_inend)
495 if (!smtp_refill(*len))
496 { *len = 0; return NULL; }
498 if ((size = smtp_inend - smtp_inptr) > *len) size = *len;
509 int n = smtp_inend - smtp_inptr;
511 dkim_exim_verify_feed(smtp_inptr, n);
516 /* Get a byte from the smtp input, in CHUNKING mode. Handle ack of the
517 previous BDAT chunk and getting new ones when we run out. Uses the
518 underlying smtp_getc or tls_getc both for that and for getting the
519 (buffered) data byte. EOD signals (an expected) no further data.
520 ERR signals a protocol error, and EOF a closed input stream.
522 Called from read_bdat_smtp() in receive.c for the message body, but also
523 by the headers read loop in receive_msg(); manipulates chunking_state
524 to handle the BDAT command/response.
525 Placed here due to the correlation with the above smtp_getc(), which it wraps,
526 and also by the need to do smtp command/response handling.
528 Arguments: lim (ignored)
529 Returns: the next character or ERR, EOD or EOF
533 bdat_getc(unsigned lim)
535 uschar * user_msg = NULL;
544 if (chunking_data_left > 0)
545 return lwr_receive_getc(chunking_data_left--);
547 receive_getc = lwr_receive_getc;
548 receive_getbuf = lwr_receive_getbuf;
549 receive_ungetc = lwr_receive_ungetc;
551 dkim_save = dkim_collect_input;
552 dkim_collect_input = FALSE;
555 /* Unless PIPELINING was offered, there should be no next command
556 until after we ack that chunk */
558 if (!pipelining_advertised && !check_sync())
560 unsigned n = smtp_inend - smtp_inptr;
563 incomplete_transaction_log(US"sync failure");
564 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP protocol synchronization error "
565 "(next input sent too soon: pipelining was not advertised): "
566 "rejected \"%s\" %s next input=\"%s\"",
567 smtp_cmd_buffer, host_and_ident(TRUE),
568 string_printing(string_copyn(smtp_inptr, n)));
569 (void) synprot_error(L_smtp_protocol_error, 554, NULL,
570 US"SMTP synchronization error");
571 goto repeat_until_rset;
574 /* If not the last, ack the received chunk. The last response is delayed
575 until after the data ACL decides on it */
577 if (chunking_state == CHUNKING_LAST)
580 dkim_exim_verify_feed(NULL, 0); /* notify EOD */
585 smtp_printf("250 %u byte chunk received\r\n", FALSE, chunking_datasize);
586 chunking_state = CHUNKING_OFFERED;
587 DEBUG(D_receive) debug_printf("chunking state %d\n", (int)chunking_state);
589 /* Expect another BDAT cmd from input. RFC 3030 says nothing about
590 QUIT, RSET or NOOP but handling them seems obvious */
593 switch(smtp_read_command(TRUE, 1))
596 (void) synprot_error(L_smtp_protocol_error, 503, NULL,
597 US"only BDAT permissible after non-LAST BDAT");
600 switch(smtp_read_command(TRUE, 1))
602 case QUIT_CMD: smtp_quit_handler(&user_msg, &log_msg); /*FALLTHROUGH */
603 case EOF_CMD: return EOF;
604 case RSET_CMD: smtp_rset_handler(); return ERR;
605 default: if (synprot_error(L_smtp_protocol_error, 503, NULL,
606 US"only RSET accepted now") > 0)
608 goto repeat_until_rset;
612 smtp_quit_handler(&user_msg, &log_msg);
623 smtp_printf("250 OK\r\n", FALSE);
630 if (sscanf(CS smtp_cmd_data, "%u %n", &chunking_datasize, &n) < 1)
632 (void) synprot_error(L_smtp_protocol_error, 501, NULL,
633 US"missing size for BDAT command");
636 chunking_state = strcmpic(smtp_cmd_data+n, US"LAST") == 0
637 ? CHUNKING_LAST : CHUNKING_ACTIVE;
638 chunking_data_left = chunking_datasize;
639 DEBUG(D_receive) debug_printf("chunking state %d, %d bytes\n",
640 (int)chunking_state, chunking_data_left);
642 if (chunking_datasize == 0)
643 if (chunking_state == CHUNKING_LAST)
647 (void) synprot_error(L_smtp_protocol_error, 504, NULL,
648 US"zero size for BDAT command");
649 goto repeat_until_rset;
652 receive_getc = bdat_getc;
653 receive_getbuf = bdat_getbuf;
654 receive_ungetc = bdat_ungetc;
656 dkim_collect_input = dkim_save;
658 break; /* to top of main loop */
665 bdat_getbuf(unsigned * len)
669 if (chunking_data_left <= 0)
670 { *len = 0; return NULL; }
672 if (*len > chunking_data_left) *len = chunking_data_left;
673 buf = lwr_receive_getbuf(len); /* Either smtp_getbuf or tls_getbuf */
674 chunking_data_left -= *len;
679 bdat_flush_data(void)
681 unsigned n = chunking_data_left;
682 (void) bdat_getbuf(&n);
684 receive_getc = lwr_receive_getc;
685 receive_getbuf = lwr_receive_getbuf;
686 receive_ungetc = lwr_receive_ungetc;
688 if (chunking_state != CHUNKING_LAST)
690 chunking_state = CHUNKING_OFFERED;
691 DEBUG(D_receive) debug_printf("chunking state %d\n", (int)chunking_state);
698 /*************************************************
699 * SMTP version of ungetc() *
700 *************************************************/
702 /* Puts a character back in the input buffer. Only ever
708 Returns: the character
722 chunking_data_left++;
723 return lwr_receive_ungetc(ch);
728 /*************************************************
729 * SMTP version of feof() *
730 *************************************************/
732 /* Tests for a previous EOF
735 Returns: non-zero if the eof flag is set
747 /*************************************************
748 * SMTP version of ferror() *
749 *************************************************/
751 /* Tests for a previous read error, and returns with errno
752 restored to what it was when the error was detected.
755 Returns: non-zero if the error flag is set
761 errno = smtp_had_error;
762 return smtp_had_error;
767 /*************************************************
768 * Test for characters in the SMTP buffer *
769 *************************************************/
771 /* Used at the end of a message
780 return smtp_inptr < smtp_inend;
785 /*************************************************
786 * Write formatted string to SMTP channel *
787 *************************************************/
789 /* This is a separate function so that we don't have to repeat everything for
790 TLS support or debugging. It is global so that the daemon and the
791 authentication functions can use it. It does not return any error indication,
792 because major problems such as dropped connections won't show up till an output
793 flush for non-TLS connections. The smtp_fflush() function is available for
794 checking that: for convenience, TLS output errors are remembered here so that
795 they are also picked up later by smtp_fflush().
799 more further data expected
800 ... optional arguments
806 smtp_printf(const char *format, BOOL more, ...)
811 smtp_vprintf(format, more, ap);
815 /* This is split off so that verify.c:respond_printf() can, in effect, call
816 smtp_printf(), bearing in mind that in C a vararg function can't directly
817 call another vararg function, only a function which accepts a va_list. */
820 smtp_vprintf(const char *format, BOOL more, va_list ap)
824 yield = string_vformat(big_buffer, big_buffer_size, format, ap);
828 void *reset_point = store_get(0);
829 uschar *msg_copy, *cr, *end;
830 msg_copy = string_copy(big_buffer);
831 end = msg_copy + Ustrlen(msg_copy);
832 while ((cr = Ustrchr(msg_copy, '\r')) != NULL) /* lose CRs */
833 memmove(cr, cr + 1, (end--) - cr);
834 debug_printf("SMTP>> %s", msg_copy);
835 store_reset(reset_point);
840 log_write(0, LOG_MAIN|LOG_PANIC, "string too large in smtp_printf()");
841 smtp_closedown(US"Unexpected error");
842 exim_exit(EXIT_FAILURE);
845 /* If this is the first output for a (non-batch) RCPT command, see if all RCPTs
846 have had the same. Note: this code is also present in smtp_respond(). It would
847 be tidier to have it only in one place, but when it was added, it was easier to
848 do it that way, so as not to have to mess with the code for the RCPT command,
849 which sometimes uses smtp_printf() and sometimes smtp_respond(). */
851 if (rcpt_in_progress)
853 if (rcpt_smtp_response == NULL)
854 rcpt_smtp_response = string_copy(big_buffer);
855 else if (rcpt_smtp_response_same &&
856 Ustrcmp(rcpt_smtp_response, big_buffer) != 0)
857 rcpt_smtp_response_same = FALSE;
858 rcpt_in_progress = FALSE;
861 /* Now write the string */
864 if (tls_in.active >= 0)
866 if (tls_write(TRUE, big_buffer, Ustrlen(big_buffer), more) < 0)
867 smtp_write_error = -1;
872 if (fprintf(smtp_out, "%s", big_buffer) < 0) smtp_write_error = -1;
877 /*************************************************
878 * Flush SMTP out and check for error *
879 *************************************************/
881 /* This function isn't currently used within Exim (it detects errors when it
882 tries to read the next SMTP input), but is available for use in local_scan().
883 For non-TLS connections, it flushes the output and checks for errors. For
884 TLS-connections, it checks for a previously-detected TLS write error.
887 Returns: 0 for no error; -1 after an error
893 if (tls_in.active < 0 && fflush(smtp_out) != 0) smtp_write_error = -1;
894 return smtp_write_error;
899 /*************************************************
900 * SMTP command read timeout *
901 *************************************************/
903 /* Signal handler for timing out incoming SMTP commands. This attempts to
906 Argument: signal number (SIGALRM)
911 command_timeout_handler(int sig)
913 sig = sig; /* Keep picky compilers happy */
914 log_write(L_lost_incoming_connection,
915 LOG_MAIN, "SMTP command timeout on%s connection from %s",
916 (tls_in.active >= 0)? " TLS" : "",
917 host_and_ident(FALSE));
918 if (smtp_batched_input)
919 moan_smtp_batch(NULL, "421 SMTP command timeout"); /* Does not return */
920 smtp_notquit_exit(US"command-timeout", US"421",
921 US"%s: SMTP command timeout - closing connection", smtp_active_hostname);
922 exim_exit(EXIT_FAILURE);
927 /*************************************************
929 *************************************************/
931 /* Signal handler for handling SIGTERM. Again, try to finish tidily.
933 Argument: signal number (SIGTERM)
938 command_sigterm_handler(int sig)
940 sig = sig; /* Keep picky compilers happy */
941 log_write(0, LOG_MAIN, "%s closed after SIGTERM", smtp_get_connection_info());
942 if (smtp_batched_input)
943 moan_smtp_batch(NULL, "421 SIGTERM received"); /* Does not return */
944 smtp_notquit_exit(US"signal-exit", US"421",
945 US"%s: Service not available - closing connection", smtp_active_hostname);
946 exim_exit(EXIT_FAILURE);
953 /*************************************************
954 * Restore socket timeout to previous value *
955 *************************************************/
956 /* If the previous value was successfully retrieved, restore
957 it before returning control to the non-proxy routines
959 Arguments: fd - File descriptor for input
960 get_ok - Successfully retrieved previous values
961 tvtmp - Time struct with previous values
962 vslen - Length of time struct
966 restore_socket_timeout(int fd, int get_ok, struct timeval * tvtmp, socklen_t vslen)
969 (void) setsockopt(fd, SOL_SOCKET, SO_RCVTIMEO, CS tvtmp, vslen);
972 /*************************************************
973 * Check if host is required proxy host *
974 *************************************************/
975 /* The function determines if inbound host will be a regular smtp host
976 or if it is configured that it must use Proxy Protocol. A local
984 check_proxy_protocol_host()
988 if ( sender_host_address
989 && (rc = verify_check_this_host(CUSS &hosts_proxy, NULL, NULL,
990 sender_host_address, NULL)) == OK)
993 debug_printf("Detected proxy protocol configured host\n");
994 proxy_session = TRUE;
996 return proxy_session;
1000 /*************************************************
1001 * Read data until newline or end of buffer *
1002 *************************************************/
1003 /* While SMTP is server-speaks-first, TLS is client-speaks-first, so we can't
1004 read an entire buffer and assume there will be nothing past a proxy protocol
1005 header. Our approach normally is to use stdio, but again that relies upon
1006 "STARTTLS\r\n" and a server response before the client starts TLS handshake, or
1007 reading _nothing_ before client TLS handshake. So we don't want to use the
1008 usual buffering reads which may read enough to block TLS starting.
1010 So unfortunately we're down to "read one byte at a time, with a syscall each,
1011 and expect a little overhead", for all proxy-opened connections which are v1,
1012 just to handle the TLS-on-connect case. Since SSL functions wrap the
1013 underlying fd, we can't assume that we can feed them any already-read content.
1015 We need to know where to read to, the max capacity, and we'll read until we
1016 get a CR and one more character. Let the caller scream if it's CR+!LF.
1018 Return the amount read.
1022 swallow_until_crlf(int fd, uschar *base, int already, int capacity)
1024 uschar *to = base + already;
1030 /* For "PROXY UNKNOWN\r\n" we, at time of writing, expect to have read
1031 up through the \r; for the _normal_ case, we haven't yet seen the \r. */
1033 cr = memchr(base, '\r', already);
1036 if ((cr - base) < already - 1)
1038 /* \r and presumed \n already within what we have; probably not
1039 actually proxy protocol, but abort cleanly. */
1042 /* \r is last character read, just need one more. */
1046 while (capacity > 0)
1048 do { ret = recv(fd, to, 1, 0); } while (ret == -1 && errno == EINTR);
1060 /* reached end without having room for a final newline, abort */
1065 /*************************************************
1066 * Setup host for proxy protocol *
1067 *************************************************/
1068 /* The function configures the connection based on a header from the
1069 inbound host to use Proxy Protocol. The specification is very exact
1070 so exit with an error if do not find the exact required pieces. This
1071 includes an incorrect number of spaces separating args.
1074 Returns: Boolean success
1078 setup_proxy_protocol_host()
1090 struct { /* TCP/UDP over IPv4, len = 12 */
1096 struct { /* TCP/UDP over IPv6, len = 36 */
1097 uint8_t src_addr[16];
1098 uint8_t dst_addr[16];
1102 struct { /* AF_UNIX sockets, len = 216 */
1103 uschar src_addr[108];
1104 uschar dst_addr[108];
1110 /* Temp variables used in PPv2 address:port parsing */
1112 char tmpip[INET_ADDRSTRLEN];
1113 struct sockaddr_in tmpaddr;
1114 char tmpip6[INET6_ADDRSTRLEN];
1115 struct sockaddr_in6 tmpaddr6;
1117 /* We can't read "all data until end" because while SMTP is
1118 server-speaks-first, the TLS handshake is client-speaks-first, so for
1119 TLS-on-connect ports the proxy protocol header will usually be immediately
1120 followed by a TLS handshake, and with N TLS libraries, we can't reliably
1121 reinject data for reading by those. So instead we first read "enough to be
1122 safely read within the header, and figure out how much more to read".
1123 For v1 we will later read to the end-of-line, for v2 we will read based upon
1126 The v2 sig is 12 octets, and another 4 gets us the length, so we know how much
1127 data is needed total. For v1, where the line looks like:
1128 PROXY TCPn L3src L3dest SrcPort DestPort \r\n
1130 However, for v1 there's also `PROXY UNKNOWN\r\n` which is only 15 octets.
1131 We seem to support that. So, if we read 14 octets then we can tell if we're
1132 v2 or v1. If we're v1, we can continue reading as normal.
1134 If we're v2, we can't slurp up the entire header. We need the length in the
1135 15th & 16th octets, then to read everything after that.
1137 So to safely handle v1 and v2, with client-sent-first supported correctly,
1138 we have to do a minimum of 3 read calls, not 1. Eww.
1141 #define PROXY_INITIAL_READ 14
1142 #define PROXY_V2_HEADER_SIZE 16
1143 #if PROXY_INITIAL_READ > PROXY_V2_HEADER_SIZE
1144 # error Code bug in sizes of data to read for proxy usage
1149 int fd = fileno(smtp_in);
1150 const char v2sig[12] = "\x0D\x0A\x0D\x0A\x00\x0D\x0A\x51\x55\x49\x54\x0A";
1151 uschar * iptype; /* To display debug info */
1153 struct timeval tvtmp;
1154 socklen_t vslen = sizeof(struct timeval);
1157 /* Save current socket timeout values */
1158 get_ok = getsockopt(fd, SOL_SOCKET, SO_RCVTIMEO, CS &tvtmp, &vslen);
1160 /* Proxy Protocol host must send header within a short time
1161 (default 3 seconds) or it's considered invalid */
1162 tv.tv_sec = PROXY_NEGOTIATION_TIMEOUT_SEC;
1163 tv.tv_usec = PROXY_NEGOTIATION_TIMEOUT_USEC;
1164 if (setsockopt(fd, SOL_SOCKET, SO_RCVTIMEO, CS &tv, sizeof(tv)) < 0)
1169 /* The inbound host was declared to be a Proxy Protocol host, so
1170 don't do a PEEK into the data, actually slurp up enough to be
1171 "safe". Can't take it all because TLS-on-connect clients follow
1172 immediately with TLS handshake. */
1173 ret = recv(fd, &hdr, PROXY_INITIAL_READ, 0);
1175 while (ret == -1 && errno == EINTR);
1180 /* For v2, handle reading the length, and then the rest. */
1181 if ((ret == PROXY_INITIAL_READ) && (memcmp(&hdr.v2, v2sig, sizeof(v2sig)) == 0))
1186 /* First get the length fields. */
1189 retmore = recv(fd, (uschar*)&hdr + ret, PROXY_V2_HEADER_SIZE - PROXY_INITIAL_READ, 0);
1190 } while (retmore == -1 && errno == EINTR);
1195 ver = (hdr.v2.ver_cmd & 0xf0) >> 4;
1197 /* May 2014: haproxy combined the version and command into one byte to
1198 allow two full bytes for the length field in order to proxy SSL
1199 connections. SSL Proxy is not supported in this version of Exim, but
1200 must still separate values here. */
1204 DEBUG(D_receive) debug_printf("Invalid Proxy Protocol version: %d\n", ver);
1208 /* The v2 header will always be 16 bytes per the spec. */
1209 size = 16 + ntohs(hdr.v2.len);
1210 DEBUG(D_receive) debug_printf("Detected PROXYv2 header, size %d (limit %d)\n",
1211 size, (int)sizeof(hdr));
1213 /* We should now have 16 octets (PROXY_V2_HEADER_SIZE), and we know the total
1214 amount that we need. Double-check that the size is not unreasonable, then
1216 if (size > sizeof(hdr))
1218 DEBUG(D_receive) debug_printf("PROXYv2 header size unreasonably large; security attack?\n");
1226 retmore = recv(fd, (uschar*)&hdr + ret, size-ret, 0);
1227 } while (retmore == -1 && errno == EINTR);
1231 DEBUG(D_receive) debug_printf("PROXYv2: have %d/%d required octets\n", ret, size);
1232 } while (ret < size);
1234 } /* end scope for getting rest of data for v2 */
1236 /* At this point: if PROXYv2, we've read the exact size required for all data;
1237 if PROXYv1 then we've read "less than required for any valid line" and should
1240 if (ret >= 16 && memcmp(&hdr.v2, v2sig, 12) == 0)
1242 uint8_t cmd = (hdr.v2.ver_cmd & 0x0f);
1246 case 0x01: /* PROXY command */
1249 case 0x11: /* TCPv4 address type */
1251 tmpaddr.sin_addr.s_addr = hdr.v2.addr.ip4.src_addr;
1252 inet_ntop(AF_INET, &tmpaddr.sin_addr, CS &tmpip, sizeof(tmpip));
1253 if (!string_is_ip_address(US tmpip, NULL))
1255 DEBUG(D_receive) debug_printf("Invalid %s source IP\n", iptype);
1258 proxy_local_address = sender_host_address;
1259 sender_host_address = string_copy(US tmpip);
1260 tmpport = ntohs(hdr.v2.addr.ip4.src_port);
1261 proxy_local_port = sender_host_port;
1262 sender_host_port = tmpport;
1263 /* Save dest ip/port */
1264 tmpaddr.sin_addr.s_addr = hdr.v2.addr.ip4.dst_addr;
1265 inet_ntop(AF_INET, &tmpaddr.sin_addr, CS &tmpip, sizeof(tmpip));
1266 if (!string_is_ip_address(US tmpip, NULL))
1268 DEBUG(D_receive) debug_printf("Invalid %s dest port\n", iptype);
1271 proxy_external_address = string_copy(US tmpip);
1272 tmpport = ntohs(hdr.v2.addr.ip4.dst_port);
1273 proxy_external_port = tmpport;
1275 case 0x21: /* TCPv6 address type */
1277 memmove(tmpaddr6.sin6_addr.s6_addr, hdr.v2.addr.ip6.src_addr, 16);
1278 inet_ntop(AF_INET6, &tmpaddr6.sin6_addr, CS &tmpip6, sizeof(tmpip6));
1279 if (!string_is_ip_address(US tmpip6, NULL))
1281 DEBUG(D_receive) debug_printf("Invalid %s source IP\n", iptype);
1284 proxy_local_address = sender_host_address;
1285 sender_host_address = string_copy(US tmpip6);
1286 tmpport = ntohs(hdr.v2.addr.ip6.src_port);
1287 proxy_local_port = sender_host_port;
1288 sender_host_port = tmpport;
1289 /* Save dest ip/port */
1290 memmove(tmpaddr6.sin6_addr.s6_addr, hdr.v2.addr.ip6.dst_addr, 16);
1291 inet_ntop(AF_INET6, &tmpaddr6.sin6_addr, CS &tmpip6, sizeof(tmpip6));
1292 if (!string_is_ip_address(US tmpip6, NULL))
1294 DEBUG(D_receive) debug_printf("Invalid %s dest port\n", iptype);
1297 proxy_external_address = string_copy(US tmpip6);
1298 tmpport = ntohs(hdr.v2.addr.ip6.dst_port);
1299 proxy_external_port = tmpport;
1303 debug_printf("Unsupported PROXYv2 connection type: 0x%02x\n",
1307 /* Unsupported protocol, keep local connection address */
1309 case 0x00: /* LOCAL command */
1310 /* Keep local connection address for LOCAL */
1315 debug_printf("Unsupported PROXYv2 command: 0x%x\n", cmd);
1319 else if (ret >= 8 && memcmp(hdr.v1.line, "PROXY", 5) == 0)
1323 uschar *sp; /* Utility variables follow */
1328 /* get the rest of the line */
1329 r2 = swallow_until_crlf(fd, (uschar*)&hdr, ret, sizeof(hdr)-ret);
1334 p = string_copy(hdr.v1.line);
1335 end = memchr(p, '\r', ret - 1);
1337 if (!end || (end == (uschar*)&hdr + ret) || end[1] != '\n')
1339 DEBUG(D_receive) debug_printf("Partial or invalid PROXY header\n");
1342 *end = '\0'; /* Terminate the string */
1343 size = end + 2 - p; /* Skip header + CRLF */
1344 DEBUG(D_receive) debug_printf("Detected PROXYv1 header\n");
1345 DEBUG(D_receive) debug_printf("Bytes read not within PROXY header: %d\n", ret - size);
1346 /* Step through the string looking for the required fields. Ensure
1347 strict adherence to required formatting, exit for any error. */
1349 if (!isspace(*(p++)))
1351 DEBUG(D_receive) debug_printf("Missing space after PROXY command\n");
1354 if (!Ustrncmp(p, CCS"TCP4", 4))
1356 else if (!Ustrncmp(p,CCS"TCP6", 4))
1358 else if (!Ustrncmp(p,CCS"UNKNOWN", 7))
1360 iptype = US"Unknown";
1365 DEBUG(D_receive) debug_printf("Invalid TCP type\n");
1369 p += Ustrlen(iptype);
1370 if (!isspace(*(p++)))
1372 DEBUG(D_receive) debug_printf("Missing space after TCP4/6 command\n");
1375 /* Find the end of the arg */
1376 if ((sp = Ustrchr(p, ' ')) == NULL)
1379 debug_printf("Did not find proxied src %s\n", iptype);
1383 if(!string_is_ip_address(p, NULL))
1386 debug_printf("Proxied src arg is not an %s address\n", iptype);
1389 proxy_local_address = sender_host_address;
1390 sender_host_address = p;
1392 if ((sp = Ustrchr(p, ' ')) == NULL)
1395 debug_printf("Did not find proxy dest %s\n", iptype);
1399 if(!string_is_ip_address(p, NULL))
1402 debug_printf("Proxy dest arg is not an %s address\n", iptype);
1405 proxy_external_address = p;
1407 if ((sp = Ustrchr(p, ' ')) == NULL)
1409 DEBUG(D_receive) debug_printf("Did not find proxied src port\n");
1413 tmp_port = strtol(CCS p, &endc, 10);
1414 if (*endc || tmp_port == 0)
1417 debug_printf("Proxied src port '%s' not an integer\n", p);
1420 proxy_local_port = sender_host_port;
1421 sender_host_port = tmp_port;
1423 if ((sp = Ustrchr(p, '\0')) == NULL)
1425 DEBUG(D_receive) debug_printf("Did not find proxy dest port\n");
1428 tmp_port = strtol(CCS p, &endc, 10);
1429 if (*endc || tmp_port == 0)
1432 debug_printf("Proxy dest port '%s' not an integer\n", p);
1435 proxy_external_port = tmp_port;
1436 /* Already checked for /r /n above. Good V1 header received. */
1440 /* Wrong protocol */
1441 DEBUG(D_receive) debug_printf("Invalid proxy protocol version negotiation\n");
1442 (void) swallow_until_crlf(fd, (uschar*)&hdr, ret, sizeof(hdr)-ret);
1448 debug_printf("Valid %s sender from Proxy Protocol header\n", iptype);
1449 yield = proxy_session;
1451 /* Don't flush any potential buffer contents. Any input on proxyfail
1452 should cause a synchronization failure */
1455 restore_socket_timeout(fd, get_ok, &tvtmp, vslen);
1460 sender_host_name = NULL;
1461 (void) host_name_lookup();
1462 host_build_sender_fullhost();
1466 proxy_session_failed = TRUE;
1468 debug_printf("Failure to extract proxied host, only QUIT allowed\n");
1475 /*************************************************
1476 * Read one command line *
1477 *************************************************/
1479 /* Strictly, SMTP commands coming over the net are supposed to end with CRLF.
1480 There are sites that don't do this, and in any case internal SMTP probably
1481 should check only for LF. Consequently, we check here for LF only. The line
1482 ends up with [CR]LF removed from its end. If we get an overlong line, treat as
1483 an unknown command. The command is read into the global smtp_cmd_buffer so that
1484 it is available via $smtp_command.
1486 The character reading routine sets up a timeout for each block actually read
1487 from the input (which may contain more than one command). We set up a special
1488 signal handler that closes down the session on a timeout. Control does not
1489 return when it runs.
1492 check_sync if TRUE, check synchronization rules if global option is TRUE
1493 buffer_lim maximum to buffer in lower layer
1495 Returns: a code identifying the command (enumerated above)
1499 smtp_read_command(BOOL check_sync, unsigned buffer_lim)
1504 BOOL hadnull = FALSE;
1506 os_non_restarting_signal(SIGALRM, command_timeout_handler);
1508 while ((c = (receive_getc)(buffer_lim)) != '\n' && c != EOF)
1510 if (ptr >= SMTP_CMD_BUFFER_SIZE)
1512 os_non_restarting_signal(SIGALRM, sigalrm_handler);
1520 smtp_cmd_buffer[ptr++] = c;
1523 receive_linecount++; /* For BSMTP errors */
1524 os_non_restarting_signal(SIGALRM, sigalrm_handler);
1526 /* If hit end of file, return pseudo EOF command. Whether we have a
1527 part-line already read doesn't matter, since this is an error state. */
1529 if (c == EOF) return EOF_CMD;
1531 /* Remove any CR and white space at the end of the line, and terminate the
1534 while (ptr > 0 && isspace(smtp_cmd_buffer[ptr-1])) ptr--;
1535 smtp_cmd_buffer[ptr] = 0;
1537 DEBUG(D_receive) debug_printf("SMTP<< %s\n", smtp_cmd_buffer);
1539 /* NULLs are not allowed in SMTP commands */
1541 if (hadnull) return BADCHAR_CMD;
1543 /* Scan command list and return identity, having set the data pointer
1544 to the start of the actual data characters. Check for SMTP synchronization
1547 for (p = cmd_list; p < cmd_list_end; p++)
1549 #ifdef SUPPORT_PROXY
1550 /* Only allow QUIT command if Proxy Protocol parsing failed */
1551 if (proxy_session && proxy_session_failed && p->cmd != QUIT_CMD)
1555 && strncmpic(smtp_cmd_buffer, US p->name, p->len) == 0
1556 && ( smtp_cmd_buffer[p->len-1] == ':' /* "mail from:" or "rcpt to:" */
1557 || smtp_cmd_buffer[p->len] == 0
1558 || smtp_cmd_buffer[p->len] == ' '
1561 if (smtp_inptr < smtp_inend && /* Outstanding input */
1562 p->cmd < sync_cmd_limit && /* Command should sync */
1563 check_sync && /* Local flag set */
1564 smtp_enforce_sync && /* Global flag set */
1565 sender_host_address != NULL && /* Not local input */
1566 !sender_host_notsocket) /* Really is a socket */
1569 /* The variables $smtp_command and $smtp_command_argument point into the
1570 unmodified input buffer. A copy of the latter is taken for actual
1571 processing, so that it can be chopped up into separate parts if necessary,
1572 for example, when processing a MAIL command options such as SIZE that can
1573 follow the sender address. */
1575 smtp_cmd_argument = smtp_cmd_buffer + p->len;
1576 while (isspace(*smtp_cmd_argument)) smtp_cmd_argument++;
1577 Ustrcpy(smtp_data_buffer, smtp_cmd_argument);
1578 smtp_cmd_data = smtp_data_buffer;
1580 /* Count non-mail commands from those hosts that are controlled in this
1581 way. The default is all hosts. We don't waste effort checking the list
1582 until we get a non-mail command, but then cache the result to save checking
1583 again. If there's a DEFER while checking the host, assume it's in the list.
1585 Note that one instance of RSET, EHLO/HELO, and STARTTLS is allowed at the
1586 start of each incoming message by fiddling with the value in the table. */
1588 if (!p->is_mail_cmd)
1590 if (count_nonmail == TRUE_UNSET) count_nonmail =
1591 verify_check_host(&smtp_accept_max_nonmail_hosts) != FAIL;
1592 if (count_nonmail && ++nonmail_command_count > smtp_accept_max_nonmail)
1593 return TOO_MANY_NONMAIL_CMD;
1596 /* If there is data for a command that does not expect it, generate the
1599 return (p->has_arg || *smtp_cmd_data == 0)? p->cmd : BADARG_CMD;
1603 #ifdef SUPPORT_PROXY
1604 /* Only allow QUIT command if Proxy Protocol parsing failed */
1605 if (proxy_session && proxy_session_failed)
1606 return PROXY_FAIL_IGNORE_CMD;
1609 /* Enforce synchronization for unknown commands */
1611 if (smtp_inptr < smtp_inend && /* Outstanding input */
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 */
1623 /*************************************************
1624 * Forced closedown of call *
1625 *************************************************/
1627 /* This function is called from log.c when Exim is dying because of a serious
1628 disaster, and also from some other places. If an incoming non-batched SMTP
1629 channel is open, it swallows the rest of the incoming message if in the DATA
1630 phase, sends the reply string, and gives an error to all subsequent commands
1631 except QUIT. The existence of an SMTP call is detected by the non-NULLness of
1635 message SMTP reply string to send, excluding the code
1641 smtp_closedown(uschar *message)
1643 if (smtp_in == NULL || smtp_batched_input) return;
1644 receive_swallow_smtp();
1645 smtp_printf("421 %s\r\n", FALSE, message);
1647 for (;;) switch(smtp_read_command(FALSE, GETC_BUFFER_UNLIMITED))
1653 smtp_printf("221 %s closing connection\r\n", FALSE, smtp_active_hostname);
1658 smtp_printf("250 Reset OK\r\n", FALSE);
1662 smtp_printf("421 %s\r\n", FALSE, message);
1670 /*************************************************
1671 * Set up connection info for logging *
1672 *************************************************/
1674 /* This function is called when logging information about an SMTP connection.
1675 It sets up appropriate source information, depending on the type of connection.
1676 If sender_fullhost is NULL, we are at a very early stage of the connection;
1677 just use the IP address.
1680 Returns: a string describing the connection
1684 smtp_get_connection_info(void)
1686 const uschar * hostname = sender_fullhost
1687 ? sender_fullhost : sender_host_address;
1690 return string_sprintf("SMTP connection from %s", hostname);
1692 if (sender_host_unknown || sender_host_notsocket)
1693 return string_sprintf("SMTP connection from %s", sender_ident);
1696 return string_sprintf("SMTP connection from %s (via inetd)", hostname);
1698 if (LOGGING(incoming_interface) && interface_address != NULL)
1699 return string_sprintf("SMTP connection from %s I=[%s]:%d", hostname,
1700 interface_address, interface_port);
1702 return string_sprintf("SMTP connection from %s", hostname);
1708 /* Append TLS-related information to a log line
1711 s String under construction: allocated string to extend, or NULL
1712 sizep Pointer to current allocation size (update on return), or NULL
1713 ptrp Pointer to index for new entries in string (update on return), or NULL
1715 Returns: Allocated string or NULL
1718 s_tlslog(uschar * s, int * sizep, int * ptrp)
1720 int size = sizep ? *sizep : 0;
1721 int ptr = ptrp ? *ptrp : 0;
1723 if (LOGGING(tls_cipher) && tls_in.cipher != NULL)
1724 s = string_append(s, &size, &ptr, 2, US" X=", tls_in.cipher);
1725 if (LOGGING(tls_certificate_verified) && tls_in.cipher != NULL)
1726 s = string_append(s, &size, &ptr, 2, US" CV=",
1727 tls_in.certificate_verified? "yes":"no");
1728 if (LOGGING(tls_peerdn) && tls_in.peerdn != NULL)
1729 s = string_append(s, &size, &ptr, 3, US" DN=\"",
1730 string_printing(tls_in.peerdn), US"\"");
1731 if (LOGGING(tls_sni) && tls_in.sni != NULL)
1732 s = string_append(s, &size, &ptr, 3, US" SNI=\"",
1733 string_printing(tls_in.sni), US"\"");
1738 if (sizep) *sizep = size;
1739 if (ptrp) *ptrp = ptr;
1745 /*************************************************
1746 * Log lack of MAIL if so configured *
1747 *************************************************/
1749 /* This function is called when an SMTP session ends. If the log selector
1750 smtp_no_mail is set, write a log line giving some details of what has happened
1751 in the SMTP session.
1758 smtp_log_no_mail(void)
1763 if (smtp_mailcmd_count > 0 || !LOGGING(smtp_no_mail))
1769 if (sender_host_authenticated != NULL)
1771 s = string_append(s, &size, &ptr, 2, US" A=", sender_host_authenticated);
1772 if (authenticated_id != NULL)
1773 s = string_append(s, &size, &ptr, 2, US":", authenticated_id);
1777 s = s_tlslog(s, &size, &ptr);
1780 sep = (smtp_connection_had[SMTP_HBUFF_SIZE-1] != SCH_NONE)?
1781 US" C=..." : US" C=";
1782 for (i = smtp_ch_index; i < SMTP_HBUFF_SIZE; i++)
1784 if (smtp_connection_had[i] != SCH_NONE)
1786 s = string_append(s, &size, &ptr, 2, sep,
1787 smtp_names[smtp_connection_had[i]]);
1792 for (i = 0; i < smtp_ch_index; i++)
1794 s = string_append(s, &size, &ptr, 2, sep, smtp_names[smtp_connection_had[i]]);
1798 if (s != NULL) s[ptr] = 0; else s = US"";
1799 log_write(0, LOG_MAIN, "no MAIL in SMTP connection from %s D=%s%s",
1800 host_and_ident(FALSE),
1801 readconf_printtime( (int) ((long)time(NULL) - (long)smtp_connection_start)),
1807 /*************************************************
1808 * Check HELO line and set sender_helo_name *
1809 *************************************************/
1811 /* Check the format of a HELO line. The data for HELO/EHLO is supposed to be
1812 the domain name of the sending host, or an ip literal in square brackets. The
1813 argument is placed in sender_helo_name, which is in malloc store, because it
1814 must persist over multiple incoming messages. If helo_accept_junk is set, this
1815 host is permitted to send any old junk (needed for some broken hosts).
1816 Otherwise, helo_allow_chars can be used for rogue characters in general
1817 (typically people want to let in underscores).
1820 s the data portion of the line (already past any white space)
1822 Returns: TRUE or FALSE
1826 check_helo(uschar *s)
1829 uschar *end = s + Ustrlen(s);
1830 BOOL yield = helo_accept_junk;
1832 /* Discard any previous helo name */
1834 if (sender_helo_name != NULL)
1836 store_free(sender_helo_name);
1837 sender_helo_name = NULL;
1840 /* Skip tests if junk is permitted. */
1844 /* Allow the new standard form for IPv6 address literals, namely,
1845 [IPv6:....], and because someone is bound to use it, allow an equivalent
1846 IPv4 form. Allow plain addresses as well. */
1853 if (strncmpic(s, US"[IPv6:", 6) == 0)
1854 yield = (string_is_ip_address(s+6, NULL) == 6);
1855 else if (strncmpic(s, US"[IPv4:", 6) == 0)
1856 yield = (string_is_ip_address(s+6, NULL) == 4);
1858 yield = (string_is_ip_address(s+1, NULL) != 0);
1863 /* Non-literals must be alpha, dot, hyphen, plus any non-valid chars
1864 that have been configured (usually underscore - sigh). */
1871 if (!isalnum(*s) && *s != '.' && *s != '-' &&
1872 Ustrchr(helo_allow_chars, *s) == NULL)
1882 /* Save argument if OK */
1884 if (yield) sender_helo_name = string_copy_malloc(start);
1892 /*************************************************
1893 * Extract SMTP command option *
1894 *************************************************/
1896 /* This function picks the next option setting off the end of smtp_cmd_data. It
1897 is called for MAIL FROM and RCPT TO commands, to pick off the optional ESMTP
1898 things that can appear there.
1901 name point this at the name
1902 value point this at the data string
1904 Returns: TRUE if found an option
1908 extract_option(uschar **name, uschar **value)
1911 uschar *v = smtp_cmd_data + Ustrlen(smtp_cmd_data) - 1;
1912 while (isspace(*v)) v--;
1914 while (v > smtp_cmd_data && *v != '=' && !isspace(*v))
1916 /* Take care to not stop at a space embedded in a quoted local-part */
1918 if (*v == '"') do v--; while (*v != '"' && v > smtp_cmd_data+1);
1925 while(isalpha(n[-1])) n--;
1926 /* RFC says SP, but TAB seen in wild and other major MTAs accept it */
1927 if (!isspace(n[-1])) return FALSE;
1933 if (v == smtp_cmd_data) return FALSE;
1945 /*************************************************
1946 * Reset for new message *
1947 *************************************************/
1949 /* This function is called whenever the SMTP session is reset from
1950 within either of the setup functions.
1952 Argument: the stacking pool storage reset point
1957 smtp_reset(void *reset_point)
1959 recipients_list = NULL;
1960 rcpt_count = rcpt_defer_count = rcpt_fail_count =
1961 raw_recipients_count = recipients_count = recipients_list_max = 0;
1962 message_linecount = 0;
1964 acl_added_headers = NULL;
1965 acl_removed_headers = NULL;
1966 queue_only_policy = FALSE;
1967 rcpt_smtp_response = NULL;
1968 rcpt_smtp_response_same = TRUE;
1969 rcpt_in_progress = FALSE;
1970 deliver_freeze = FALSE; /* Can be set by ACL */
1971 freeze_tell = freeze_tell_config; /* Can be set by ACL */
1972 fake_response = OK; /* Can be set by ACL */
1973 #ifdef WITH_CONTENT_SCAN
1974 no_mbox_unspool = FALSE; /* Can be set by ACL */
1976 submission_mode = FALSE; /* Can be set by ACL */
1977 suppress_local_fixups = suppress_local_fixups_default; /* Can be set by ACL */
1978 active_local_from_check = local_from_check; /* Can be set by ACL */
1979 active_local_sender_retain = local_sender_retain; /* Can be set by ACL */
1980 sending_ip_address = NULL;
1981 return_path = sender_address = NULL;
1982 sender_data = NULL; /* Can be set by ACL */
1983 deliver_localpart_orig = NULL;
1984 deliver_domain_orig = NULL;
1985 callout_address = NULL;
1986 submission_name = NULL; /* Can be set by ACL */
1987 raw_sender = NULL; /* After SMTP rewrite, before qualifying */
1988 sender_address_unrewritten = NULL; /* Set only after verify rewrite */
1989 sender_verified_list = NULL; /* No senders verified */
1990 memset(sender_address_cache, 0, sizeof(sender_address_cache));
1991 memset(sender_domain_cache, 0, sizeof(sender_domain_cache));
1993 authenticated_sender = NULL;
1994 #ifdef EXPERIMENTAL_BRIGHTMAIL
1996 bmi_verdicts = NULL;
1998 dnslist_domain = dnslist_matched = NULL;
1999 #ifndef DISABLE_DKIM
2000 dkim_signers = NULL;
2001 dkim_disable_verify = FALSE;
2002 dkim_collect_input = FALSE;
2006 deliver_host = deliver_host_address = NULL; /* Can be set by ACL */
2007 #ifndef DISABLE_PRDR
2008 prdr_requested = FALSE;
2010 #ifdef EXPERIMENTAL_SPF
2011 spf_header_comment = NULL;
2012 spf_received = NULL;
2014 spf_smtp_comment = NULL;
2017 message_smtputf8 = FALSE;
2019 body_linecount = body_zerocount = 0;
2021 sender_rate = sender_rate_limit = sender_rate_period = NULL;
2022 ratelimiters_mail = NULL; /* Updated by ratelimit ACL condition */
2023 /* Note that ratelimiters_conn persists across resets. */
2025 /* Reset message ACL variables */
2029 /* The message body variables use malloc store. They may be set if this is
2030 not the first message in an SMTP session and the previous message caused them
2031 to be referenced in an ACL. */
2035 store_free(message_body);
2036 message_body = NULL;
2039 if (message_body_end)
2041 store_free(message_body_end);
2042 message_body_end = NULL;
2045 /* Warning log messages are also saved in malloc store. They are saved to avoid
2046 repetition in the same message, but it seems right to repeat them for different
2049 while (acl_warn_logged)
2051 string_item *this = acl_warn_logged;
2052 acl_warn_logged = acl_warn_logged->next;
2055 store_reset(reset_point);
2062 /*************************************************
2063 * Initialize for incoming batched SMTP message *
2064 *************************************************/
2066 /* This function is called from smtp_setup_msg() in the case when
2067 smtp_batched_input is true. This happens when -bS is used to pass a whole batch
2068 of messages in one file with SMTP commands between them. All errors must be
2069 reported by sending a message, and only MAIL FROM, RCPT TO, and DATA are
2070 relevant. After an error on a sender, or an invalid recipient, the remainder
2071 of the message is skipped. The value of received_protocol is already set.
2074 Returns: > 0 message successfully started (reached DATA)
2075 = 0 QUIT read or end of file reached
2076 < 0 should not occur
2080 smtp_setup_batch_msg(void)
2083 void *reset_point = store_get(0);
2085 /* Save the line count at the start of each transaction - single commands
2086 like HELO and RSET count as whole transactions. */
2088 bsmtp_transaction_linecount = receive_linecount;
2090 if ((receive_feof)()) return 0; /* Treat EOF as QUIT */
2092 cancel_cutthrough_connection(TRUE, US"smtp_setup_batch_msg");
2093 smtp_reset(reset_point); /* Reset for start of message */
2095 /* Deal with SMTP commands. This loop is exited by setting done to a POSITIVE
2096 value. The values are 2 larger than the required yield of the function. */
2101 uschar *recipient = NULL;
2102 int start, end, sender_domain, recipient_domain;
2104 switch(smtp_read_command(FALSE, GETC_BUFFER_UNLIMITED))
2106 /* The HELO/EHLO commands set sender_address_helo if they have
2107 valid data; otherwise they are ignored, except that they do
2108 a reset of the state. */
2113 check_helo(smtp_cmd_data);
2117 cancel_cutthrough_connection(TRUE, US"RSET received");
2118 smtp_reset(reset_point);
2119 bsmtp_transaction_linecount = receive_linecount;
2123 /* The MAIL FROM command requires an address as an operand. All we
2124 do here is to parse it for syntactic correctness. The form "<>" is
2125 a special case which converts into an empty string. The start/end
2126 pointers in the original are not used further for this address, as
2127 it is the canonical extracted address which is all that is kept. */
2130 smtp_mailcmd_count++; /* Count for no-mail log */
2131 if (sender_address != NULL)
2132 /* The function moan_smtp_batch() does not return. */
2133 moan_smtp_batch(smtp_cmd_buffer, "503 Sender already given");
2135 if (smtp_cmd_data[0] == 0)
2136 /* The function moan_smtp_batch() does not return. */
2137 moan_smtp_batch(smtp_cmd_buffer, "501 MAIL FROM must have an address operand");
2139 /* Reset to start of message */
2141 cancel_cutthrough_connection(TRUE, US"MAIL received");
2142 smtp_reset(reset_point);
2144 /* Apply SMTP rewrite */
2146 raw_sender = ((rewrite_existflags & rewrite_smtp) != 0)?
2147 rewrite_one(smtp_cmd_data, rewrite_smtp|rewrite_smtp_sender, NULL, FALSE,
2148 US"", global_rewrite_rules) : smtp_cmd_data;
2150 /* Extract the address; the TRUE flag allows <> as valid */
2153 parse_extract_address(raw_sender, &errmess, &start, &end, &sender_domain,
2156 if (raw_sender == NULL)
2157 /* The function moan_smtp_batch() does not return. */
2158 moan_smtp_batch(smtp_cmd_buffer, "501 %s", errmess);
2160 sender_address = string_copy(raw_sender);
2162 /* Qualify unqualified sender addresses if permitted to do so. */
2164 if (sender_domain == 0 && sender_address[0] != 0 && sender_address[0] != '@')
2166 if (allow_unqualified_sender)
2168 sender_address = rewrite_address_qualify(sender_address, FALSE);
2169 DEBUG(D_receive) debug_printf("unqualified address %s accepted "
2170 "and rewritten\n", raw_sender);
2172 /* The function moan_smtp_batch() does not return. */
2173 else moan_smtp_batch(smtp_cmd_buffer, "501 sender address must contain "
2179 /* The RCPT TO command requires an address as an operand. All we do
2180 here is to parse it for syntactic correctness. There may be any number
2181 of RCPT TO commands, specifying multiple senders. We build them all into
2182 a data structure that is in argc/argv format. The start/end values
2183 given by parse_extract_address are not used, as we keep only the
2184 extracted address. */
2187 if (sender_address == NULL)
2188 /* The function moan_smtp_batch() does not return. */
2189 moan_smtp_batch(smtp_cmd_buffer, "503 No sender yet given");
2191 if (smtp_cmd_data[0] == 0)
2192 /* The function moan_smtp_batch() does not return. */
2193 moan_smtp_batch(smtp_cmd_buffer, "501 RCPT TO must have an address operand");
2195 /* Check maximum number allowed */
2197 if (recipients_max > 0 && recipients_count + 1 > recipients_max)
2198 /* The function moan_smtp_batch() does not return. */
2199 moan_smtp_batch(smtp_cmd_buffer, "%s too many recipients",
2200 recipients_max_reject? "552": "452");
2202 /* Apply SMTP rewrite, then extract address. Don't allow "<>" as a
2203 recipient address */
2205 recipient = rewrite_existflags & rewrite_smtp
2206 ? rewrite_one(smtp_cmd_data, rewrite_smtp, NULL, FALSE, US"",
2207 global_rewrite_rules)
2210 recipient = parse_extract_address(recipient, &errmess, &start, &end,
2211 &recipient_domain, FALSE);
2214 /* The function moan_smtp_batch() does not return. */
2215 moan_smtp_batch(smtp_cmd_buffer, "501 %s", errmess);
2217 /* If the recipient address is unqualified, qualify it if permitted. Then
2218 add it to the list of recipients. */
2220 if (recipient_domain == 0)
2222 if (allow_unqualified_recipient)
2224 DEBUG(D_receive) debug_printf("unqualified address %s accepted\n",
2226 recipient = rewrite_address_qualify(recipient, TRUE);
2228 /* The function moan_smtp_batch() does not return. */
2229 else moan_smtp_batch(smtp_cmd_buffer, "501 recipient address must contain "
2232 receive_add_recipient(recipient, -1);
2236 /* The DATA command is legal only if it follows successful MAIL FROM
2237 and RCPT TO commands. This function is complete when a valid DATA
2238 command is encountered. */
2241 if (sender_address == NULL || recipients_count <= 0)
2243 /* The function moan_smtp_batch() does not return. */
2244 if (sender_address == NULL)
2245 moan_smtp_batch(smtp_cmd_buffer,
2246 "503 MAIL FROM:<sender> command must precede DATA");
2248 moan_smtp_batch(smtp_cmd_buffer,
2249 "503 RCPT TO:<recipient> must precede DATA");
2253 done = 3; /* DATA successfully achieved */
2254 message_ended = END_NOTENDED; /* Indicate in middle of message */
2259 /* The VRFY, EXPN, HELP, ETRN, and NOOP commands are ignored. */
2266 bsmtp_transaction_linecount = receive_linecount;
2277 /* The function moan_smtp_batch() does not return. */
2278 moan_smtp_batch(smtp_cmd_buffer, "501 Unexpected argument data");
2283 /* The function moan_smtp_batch() does not return. */
2284 moan_smtp_batch(smtp_cmd_buffer, "501 Unexpected NULL in SMTP command");
2289 /* The function moan_smtp_batch() does not return. */
2290 moan_smtp_batch(smtp_cmd_buffer, "500 Command unrecognized");
2295 return done - 2; /* Convert yield values */
2302 smtp_log_tls_fail(uschar * errstr)
2304 uschar * conn_info = smtp_get_connection_info();
2306 if (Ustrncmp(conn_info, US"SMTP ", 5) == 0) conn_info += 5;
2307 /* I'd like to get separated H= here, but too hard for now */
2309 log_write(0, LOG_MAIN, "TLS error on %s %s", conn_info, errstr);
2314 /*************************************************
2315 * Start an SMTP session *
2316 *************************************************/
2318 /* This function is called at the start of an SMTP session. Thereafter,
2319 smtp_setup_msg() is called to initiate each separate message. This
2320 function does host-specific testing, and outputs the banner line.
2323 Returns: FALSE if the session can not continue; something has
2324 gone wrong, or the connection to the host is blocked
2328 smtp_start_session(void)
2332 uschar *user_msg, *log_msg;
2336 smtp_connection_start = time(NULL);
2337 for (smtp_ch_index = 0; smtp_ch_index < SMTP_HBUFF_SIZE; smtp_ch_index++)
2338 smtp_connection_had[smtp_ch_index] = SCH_NONE;
2341 /* Default values for certain variables */
2343 helo_seen = esmtp = helo_accept_junk = FALSE;
2344 smtp_mailcmd_count = 0;
2345 count_nonmail = TRUE_UNSET;
2346 synprot_error_count = unknown_command_count = nonmail_command_count = 0;
2347 smtp_delay_mail = smtp_rlm_base;
2348 auth_advertised = FALSE;
2349 pipelining_advertised = FALSE;
2350 pipelining_enable = TRUE;
2351 sync_cmd_limit = NON_SYNC_CMD_NON_PIPELINING;
2352 smtp_exit_function_called = FALSE; /* For avoiding loop in not-quit exit */
2354 /* If receiving by -bs from a trusted user, or testing with -bh, we allow
2355 authentication settings from -oMaa to remain in force. */
2357 if (!host_checking && !sender_host_notsocket) sender_host_authenticated = NULL;
2358 authenticated_by = NULL;
2361 tls_in.cipher = tls_in.peerdn = NULL;
2362 tls_in.ourcert = tls_in.peercert = NULL;
2364 tls_in.ocsp = OCSP_NOT_REQ;
2365 tls_advertised = FALSE;
2367 dsn_advertised = FALSE;
2369 smtputf8_advertised = FALSE;
2372 /* Reset ACL connection variables */
2376 /* Allow for trailing 0 in the command and data buffers. */
2378 if (!(smtp_cmd_buffer = US malloc(2*SMTP_CMD_BUFFER_SIZE + 2)))
2379 log_write(0, LOG_MAIN|LOG_PANIC_DIE,
2380 "malloc() failed for SMTP command buffer");
2382 smtp_cmd_buffer[0] = 0;
2383 smtp_data_buffer = smtp_cmd_buffer + SMTP_CMD_BUFFER_SIZE + 1;
2385 /* For batched input, the protocol setting can be overridden from the
2386 command line by a trusted caller. */
2388 if (smtp_batched_input)
2390 if (!received_protocol) received_protocol = US"local-bsmtp";
2393 /* For non-batched SMTP input, the protocol setting is forced here. It will be
2394 reset later if any of EHLO/AUTH/STARTTLS are received. */
2398 (sender_host_address ? protocols : protocols_local) [pnormal];
2400 /* Set up the buffer for inputting using direct read() calls, and arrange to
2401 call the local functions instead of the standard C ones. */
2403 if (!(smtp_inbuffer = (uschar *)malloc(IN_BUFFER_SIZE)))
2404 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "malloc() failed for SMTP input buffer");
2406 receive_getc = smtp_getc;
2407 receive_getbuf = smtp_getbuf;
2408 receive_get_cache = smtp_get_cache;
2409 receive_ungetc = smtp_ungetc;
2410 receive_feof = smtp_feof;
2411 receive_ferror = smtp_ferror;
2412 receive_smtp_buffered = smtp_buffered;
2413 smtp_inptr = smtp_inend = smtp_inbuffer;
2414 smtp_had_eof = smtp_had_error = 0;
2416 /* Set up the message size limit; this may be host-specific */
2418 thismessage_size_limit = expand_string_integer(message_size_limit, TRUE);
2419 if (expand_string_message != NULL)
2421 if (thismessage_size_limit == -1)
2422 log_write(0, LOG_MAIN|LOG_PANIC, "unable to expand message_size_limit: "
2423 "%s", expand_string_message);
2425 log_write(0, LOG_MAIN|LOG_PANIC, "invalid message_size_limit: "
2426 "%s", expand_string_message);
2427 smtp_closedown(US"Temporary local problem - please try later");
2431 /* When a message is input locally via the -bs or -bS options, sender_host_
2432 unknown is set unless -oMa was used to force an IP address, in which case it
2433 is checked like a real remote connection. When -bs is used from inetd, this
2434 flag is not set, causing the sending host to be checked. The code that deals
2435 with IP source routing (if configured) is never required for -bs or -bS and
2436 the flag sender_host_notsocket is used to suppress it.
2438 If smtp_accept_max and smtp_accept_reserve are set, keep some connections in
2439 reserve for certain hosts and/or networks. */
2441 if (!sender_host_unknown)
2444 BOOL reserved_host = FALSE;
2446 /* Look up IP options (source routing info) on the socket if this is not an
2447 -oMa "host", and if any are found, log them and drop the connection.
2449 Linux (and others now, see below) is different to everyone else, so there
2450 has to be some conditional compilation here. Versions of Linux before 2.1.15
2451 used a structure whose name was "options". Somebody finally realized that
2452 this name was silly, and it got changed to "ip_options". I use the
2453 newer name here, but there is a fudge in the script that sets up os.h
2454 to define a macro in older Linux systems.
2456 Sigh. Linux is a fast-moving target. Another generation of Linux uses
2457 glibc 2, which has chosen ip_opts for the structure name. This is now
2458 really a glibc thing rather than a Linux thing, so the condition name
2459 has been changed to reflect this. It is relevant also to GNU/Hurd.
2461 Mac OS 10.x (Darwin) is like the later glibc versions, but without the
2462 setting of the __GLIBC__ macro, so we can't detect it automatically. There's
2463 a special macro defined in the os.h file.
2465 Some DGUX versions on older hardware appear not to support IP options at
2466 all, so there is now a general macro which can be set to cut out this
2469 How to do this properly in IPv6 is not yet known. */
2471 #if !HAVE_IPV6 && !defined(NO_IP_OPTIONS)
2473 #ifdef GLIBC_IP_OPTIONS
2474 #if (!defined __GLIBC__) || (__GLIBC__ < 2)
2479 #elif defined DARWIN_IP_OPTIONS
2485 if (!host_checking && !sender_host_notsocket)
2488 EXIM_SOCKLEN_T optlen = sizeof(struct ip_options) + MAX_IPOPTLEN;
2489 struct ip_options *ipopt = store_get(optlen);
2491 struct ip_opts ipoptblock;
2492 struct ip_opts *ipopt = &ipoptblock;
2493 EXIM_SOCKLEN_T optlen = sizeof(ipoptblock);
2495 struct ipoption ipoptblock;
2496 struct ipoption *ipopt = &ipoptblock;
2497 EXIM_SOCKLEN_T optlen = sizeof(ipoptblock);
2500 /* Occasional genuine failures of getsockopt() have been seen - for
2501 example, "reset by peer". Therefore, just log and give up on this
2502 call, unless the error is ENOPROTOOPT. This error is given by systems
2503 that have the interfaces but not the mechanism - e.g. GNU/Hurd at the time
2504 of writing. So for that error, carry on - we just can't do an IP options
2507 DEBUG(D_receive) debug_printf("checking for IP options\n");
2509 if (getsockopt(fileno(smtp_out), IPPROTO_IP, IP_OPTIONS, (uschar *)(ipopt),
2512 if (errno != ENOPROTOOPT)
2514 log_write(0, LOG_MAIN, "getsockopt() failed from %s: %s",
2515 host_and_ident(FALSE), strerror(errno));
2516 smtp_printf("451 SMTP service not available\r\n", FALSE);
2521 /* Deal with any IP options that are set. On the systems I have looked at,
2522 the value of MAX_IPOPTLEN has been 40, meaning that there should never be
2523 more logging data than will fit in big_buffer. Nevertheless, after somebody
2524 questioned this code, I've added in some paranoid checking. */
2526 else if (optlen > 0)
2528 uschar *p = big_buffer;
2529 uschar *pend = big_buffer + big_buffer_size;
2530 uschar *opt, *adptr;
2532 struct in_addr addr;
2535 uschar *optstart = (uschar *)(ipopt->__data);
2537 uschar *optstart = (uschar *)(ipopt->ip_opts);
2539 uschar *optstart = (uschar *)(ipopt->ipopt_list);
2542 DEBUG(D_receive) debug_printf("IP options exist\n");
2544 Ustrcpy(p, "IP options on incoming call:");
2547 for (opt = optstart; opt != NULL &&
2548 opt < (uschar *)(ipopt) + optlen;)
2562 if (!string_format(p, pend-p, " %s [@%s",
2563 (*opt == IPOPT_SSRR)? "SSRR" : "LSRR",
2565 inet_ntoa(*((struct in_addr *)(&(ipopt->faddr))))))
2567 inet_ntoa(ipopt->ip_dst)))
2569 inet_ntoa(ipopt->ipopt_dst)))
2577 optcount = (opt[1] - 3) / sizeof(struct in_addr);
2579 while (optcount-- > 0)
2581 memcpy(&addr, adptr, sizeof(addr));
2582 if (!string_format(p, pend - p - 1, "%s%s",
2583 (optcount == 0)? ":" : "@", inet_ntoa(addr)))
2589 adptr += sizeof(struct in_addr);
2598 if (pend - p < 4 + 3*opt[1]) { opt = NULL; break; }
2601 for (i = 0; i < opt[1]; i++)
2603 sprintf(CS p, "%2.2x ", opt[i]);
2614 log_write(0, LOG_MAIN, "%s", big_buffer);
2616 /* Refuse any call with IP options. This is what tcpwrappers 7.5 does. */
2618 log_write(0, LOG_MAIN|LOG_REJECT,
2619 "connection from %s refused (IP options)", host_and_ident(FALSE));
2621 smtp_printf("554 SMTP service not available\r\n", FALSE);
2625 /* Length of options = 0 => there are no options */
2627 else DEBUG(D_receive) debug_printf("no IP options found\n");
2629 #endif /* HAVE_IPV6 && !defined(NO_IP_OPTIONS) */
2631 /* Set keep-alive in socket options. The option is on by default. This
2632 setting is an attempt to get rid of some hanging connections that stick in
2633 read() when the remote end (usually a dialup) goes away. */
2635 if (smtp_accept_keepalive && !sender_host_notsocket)
2636 ip_keepalive(fileno(smtp_out), sender_host_address, FALSE);
2638 /* If the current host matches host_lookup, set the name by doing a
2639 reverse lookup. On failure, sender_host_name will be NULL and
2640 host_lookup_failed will be TRUE. This may or may not be serious - optional
2643 if (verify_check_host(&host_lookup) == OK)
2645 (void)host_name_lookup();
2646 host_build_sender_fullhost();
2649 /* Delay this until we have the full name, if it is looked up. */
2651 set_process_info("handling incoming connection from %s",
2652 host_and_ident(FALSE));
2654 /* Expand smtp_receive_timeout, if needed */
2656 if (smtp_receive_timeout_s)
2659 if ( !(exp = expand_string(smtp_receive_timeout_s))
2661 || (smtp_receive_timeout = readconf_readtime(exp, 0, FALSE)) < 0
2663 log_write(0, LOG_MAIN|LOG_PANIC,
2664 "bad value for smtp_receive_timeout: '%s'", exp ? exp : US"");
2667 /* Test for explicit connection rejection */
2669 if (verify_check_host(&host_reject_connection) == OK)
2671 log_write(L_connection_reject, LOG_MAIN|LOG_REJECT, "refused connection "
2672 "from %s (host_reject_connection)", host_and_ident(FALSE));
2673 smtp_printf("554 SMTP service not available\r\n", FALSE);
2677 /* Test with TCP Wrappers if so configured. There is a problem in that
2678 hosts_ctl() returns 0 (deny) under a number of system failure circumstances,
2679 such as disks dying. In these cases, it is desirable to reject with a 4xx
2680 error instead of a 5xx error. There isn't a "right" way to detect such
2681 problems. The following kludge is used: errno is zeroed before calling
2682 hosts_ctl(). If the result is "reject", a 5xx error is given only if the
2683 value of errno is 0 or ENOENT (which happens if /etc/hosts.{allow,deny} does
2686 #ifdef USE_TCP_WRAPPERS
2688 if (!(tcp_wrappers_name = expand_string(tcp_wrappers_daemon_name)))
2689 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "Expansion of \"%s\" "
2690 "(tcp_wrappers_name) failed: %s", string_printing(tcp_wrappers_name),
2691 expand_string_message);
2693 if (!hosts_ctl(tcp_wrappers_name,
2694 sender_host_name ? CS sender_host_name : STRING_UNKNOWN,
2695 sender_host_address ? CS sender_host_address : STRING_UNKNOWN,
2696 sender_ident ? CS sender_ident : STRING_UNKNOWN))
2698 if (errno == 0 || errno == ENOENT)
2700 HDEBUG(D_receive) debug_printf("tcp wrappers rejection\n");
2701 log_write(L_connection_reject,
2702 LOG_MAIN|LOG_REJECT, "refused connection from %s "
2703 "(tcp wrappers)", host_and_ident(FALSE));
2704 smtp_printf("554 SMTP service not available\r\n", FALSE);
2708 int save_errno = errno;
2709 HDEBUG(D_receive) debug_printf("tcp wrappers rejected with unexpected "
2710 "errno value %d\n", save_errno);
2711 log_write(L_connection_reject,
2712 LOG_MAIN|LOG_REJECT, "temporarily refused connection from %s "
2713 "(tcp wrappers errno=%d)", host_and_ident(FALSE), save_errno);
2714 smtp_printf("451 Temporary local problem - please try later\r\n", FALSE);
2720 /* Check for reserved slots. The value of smtp_accept_count has already been
2721 incremented to include this process. */
2723 if (smtp_accept_max > 0 &&
2724 smtp_accept_count > smtp_accept_max - smtp_accept_reserve)
2726 if ((rc = verify_check_host(&smtp_reserve_hosts)) != OK)
2728 log_write(L_connection_reject,
2729 LOG_MAIN, "temporarily refused connection from %s: not in "
2730 "reserve list: connected=%d max=%d reserve=%d%s",
2731 host_and_ident(FALSE), smtp_accept_count - 1, smtp_accept_max,
2732 smtp_accept_reserve, (rc == DEFER)? " (lookup deferred)" : "");
2733 smtp_printf("421 %s: Too many concurrent SMTP connections; "
2734 "please try again later\r\n", FALSE, smtp_active_hostname);
2737 reserved_host = TRUE;
2740 /* If a load level above which only messages from reserved hosts are
2741 accepted is set, check the load. For incoming calls via the daemon, the
2742 check is done in the superior process if there are no reserved hosts, to
2743 save a fork. In all cases, the load average will already be available
2744 in a global variable at this point. */
2746 if (smtp_load_reserve >= 0 &&
2747 load_average > smtp_load_reserve &&
2749 verify_check_host(&smtp_reserve_hosts) != OK)
2751 log_write(L_connection_reject,
2752 LOG_MAIN, "temporarily refused connection from %s: not in "
2753 "reserve list and load average = %.2f", host_and_ident(FALSE),
2754 (double)load_average/1000.0);
2755 smtp_printf("421 %s: Too much load; please try again later\r\n", FALSE,
2756 smtp_active_hostname);
2760 /* Determine whether unqualified senders or recipients are permitted
2761 for this host. Unfortunately, we have to do this every time, in order to
2762 set the flags so that they can be inspected when considering qualifying
2763 addresses in the headers. For a site that permits no qualification, this
2764 won't take long, however. */
2766 allow_unqualified_sender =
2767 verify_check_host(&sender_unqualified_hosts) == OK;
2769 allow_unqualified_recipient =
2770 verify_check_host(&recipient_unqualified_hosts) == OK;
2772 /* Determine whether HELO/EHLO is required for this host. The requirement
2773 can be hard or soft. */
2775 helo_required = verify_check_host(&helo_verify_hosts) == OK;
2777 helo_verify = verify_check_host(&helo_try_verify_hosts) == OK;
2779 /* Determine whether this hosts is permitted to send syntactic junk
2780 after a HELO or EHLO command. */
2782 helo_accept_junk = verify_check_host(&helo_accept_junk_hosts) == OK;
2785 /* For batch SMTP input we are now done. */
2787 if (smtp_batched_input) return TRUE;
2789 /* If valid Proxy Protocol source is connecting, set up session.
2790 * Failure will not allow any SMTP function other than QUIT. */
2792 #ifdef SUPPORT_PROXY
2793 proxy_session = FALSE;
2794 proxy_session_failed = FALSE;
2795 if (check_proxy_protocol_host())
2796 setup_proxy_protocol_host();
2799 /* Start up TLS if tls_on_connect is set. This is for supporting the legacy
2800 smtps port for use with older style SSL MTAs. */
2803 if (tls_in.on_connect && tls_server_start(tls_require_ciphers, &user_msg) != OK)
2804 return smtp_log_tls_fail(user_msg);
2807 /* Run the connect ACL if it exists */
2810 if (acl_smtp_connect)
2813 if ((rc = acl_check(ACL_WHERE_CONNECT, NULL, acl_smtp_connect, &user_msg,
2816 (void) smtp_handle_acl_fail(ACL_WHERE_CONNECT, rc, user_msg, log_msg);
2821 /* Output the initial message for a two-way SMTP connection. It may contain
2822 newlines, which then cause a multi-line response to be given. */
2824 code = US"220"; /* Default status code */
2825 esc = US""; /* Default extended status code */
2826 esclen = 0; /* Length of esc */
2830 if (!(s = expand_string(smtp_banner)))
2831 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "Expansion of \"%s\" (smtp_banner) "
2832 "failed: %s", smtp_banner, expand_string_message);
2838 smtp_message_code(&code, &codelen, &s, NULL, TRUE);
2842 esclen = codelen - 4;
2846 /* Remove any terminating newlines; might as well remove trailing space too */
2849 while (p > s && isspace(p[-1])) p--;
2852 /* It seems that CC:Mail is braindead, and assumes that the greeting message
2853 is all contained in a single IP packet. The original code wrote out the
2854 greeting using several calls to fprint/fputc, and on busy servers this could
2855 cause it to be split over more than one packet - which caused CC:Mail to fall
2856 over when it got the second part of the greeting after sending its first
2857 command. Sigh. To try to avoid this, build the complete greeting message
2858 first, and output it in one fell swoop. This gives a better chance of it
2859 ending up as a single packet. */
2861 ss = store_get(size);
2865 do /* At least once, in case we have an empty string */
2868 uschar *linebreak = Ustrchr(p, '\n');
2869 ss = string_catn(ss, &size, &ptr, code, 3);
2870 if (linebreak == NULL)
2873 ss = string_catn(ss, &size, &ptr, US" ", 1);
2877 len = linebreak - p;
2878 ss = string_catn(ss, &size, &ptr, US"-", 1);
2880 ss = string_catn(ss, &size, &ptr, esc, esclen);
2881 ss = string_catn(ss, &size, &ptr, p, len);
2882 ss = string_catn(ss, &size, &ptr, US"\r\n", 2);
2884 if (linebreak != NULL) p++;
2888 ss[ptr] = 0; /* string_cat leaves room for this */
2890 /* Before we write the banner, check that there is no input pending, unless
2891 this synchronisation check is disabled. */
2895 unsigned n = smtp_inend - smtp_inptr;
2898 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP protocol "
2899 "synchronization error (input sent without waiting for greeting): "
2900 "rejected connection from %s input=\"%s\"", host_and_ident(TRUE),
2901 string_printing(string_copyn(smtp_inptr, n)));
2902 smtp_printf("554 SMTP synchronization error\r\n", FALSE);
2906 /* Now output the banner */
2908 smtp_printf("%s", FALSE, ss);
2916 /*************************************************
2917 * Handle SMTP syntax and protocol errors *
2918 *************************************************/
2920 /* Write to the log for SMTP syntax errors in incoming commands, if configured
2921 to do so. Then transmit the error response. The return value depends on the
2922 number of syntax and protocol errors in this SMTP session.
2925 type error type, given as a log flag bit
2926 code response code; <= 0 means don't send a response
2927 data data to reflect in the response (can be NULL)
2928 errmess the error message
2930 Returns: -1 limit of syntax/protocol errors NOT exceeded
2931 +1 limit of syntax/protocol errors IS exceeded
2933 These values fit in with the values of the "done" variable in the main
2934 processing loop in smtp_setup_msg(). */
2937 synprot_error(int type, int code, uschar *data, uschar *errmess)
2941 log_write(type, LOG_MAIN, "SMTP %s error in \"%s\" %s %s",
2942 (type == L_smtp_syntax_error)? "syntax" : "protocol",
2943 string_printing(smtp_cmd_buffer), host_and_ident(TRUE), errmess);
2945 if (++synprot_error_count > smtp_max_synprot_errors)
2948 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
2949 "syntax or protocol errors (last command was \"%s\")",
2950 host_and_ident(FALSE), string_printing(smtp_cmd_buffer));
2955 smtp_printf("%d%c%s%s%s\r\n", FALSE, code, yield == 1 ? '-' : ' ',
2956 data ? data : US"", data ? US": " : US"", errmess);
2958 smtp_printf("%d Too many syntax or protocol errors\r\n", FALSE, code);
2967 /*************************************************
2968 * Send SMTP response, possibly multiline *
2969 *************************************************/
2971 /* There are, it seems, broken clients out there that cannot handle multiline
2972 responses. If no_multiline_responses is TRUE (it can be set from an ACL), we
2973 output nothing for non-final calls, and only the first line for anything else.
2976 code SMTP code, may involve extended status codes
2977 codelen length of smtp code; if > 4 there's an ESC
2978 final FALSE if the last line isn't the final line
2979 msg message text, possibly containing newlines
2985 smtp_respond(uschar* code, int codelen, BOOL final, uschar *msg)
2990 if (!final && no_multiline_responses) return;
2995 esclen = codelen - 4;
2998 /* If this is the first output for a (non-batch) RCPT command, see if all RCPTs
2999 have had the same. Note: this code is also present in smtp_printf(). It would
3000 be tidier to have it only in one place, but when it was added, it was easier to
3001 do it that way, so as not to have to mess with the code for the RCPT command,
3002 which sometimes uses smtp_printf() and sometimes smtp_respond(). */
3004 if (rcpt_in_progress)
3006 if (rcpt_smtp_response == NULL)
3007 rcpt_smtp_response = string_copy(msg);
3008 else if (rcpt_smtp_response_same &&
3009 Ustrcmp(rcpt_smtp_response, msg) != 0)
3010 rcpt_smtp_response_same = FALSE;
3011 rcpt_in_progress = FALSE;
3014 /* Not output the message, splitting it up into multiple lines if necessary.
3015 We only handle pipelining these responses as far as nonfinal/final groups,
3016 not the whole MAIL/RCPT/DATA response set. */
3020 uschar *nl = Ustrchr(msg, '\n');
3023 smtp_printf("%.3s%c%.*s%s\r\n", !final, code, final ? ' ':'-', esclen, esc, msg);
3026 else if (nl[1] == 0 || no_multiline_responses)
3028 smtp_printf("%.3s%c%.*s%.*s\r\n", !final, code, final ? ' ':'-', esclen, esc,
3029 (int)(nl - msg), msg);
3034 smtp_printf("%.3s-%.*s%.*s\r\n", TRUE, code, esclen, esc, (int)(nl - msg), msg);
3036 while (isspace(*msg)) msg++;
3044 /*************************************************
3045 * Parse user SMTP message *
3046 *************************************************/
3048 /* This function allows for user messages overriding the response code details
3049 by providing a suitable response code string at the start of the message
3050 user_msg. Check the message for starting with a response code and optionally an
3051 extended status code. If found, check that the first digit is valid, and if so,
3052 change the code pointer and length to use the replacement. An invalid code
3053 causes a panic log; in this case, if the log messages is the same as the user
3054 message, we must also adjust the value of the log message to show the code that
3055 is actually going to be used (the original one).
3057 This function is global because it is called from receive.c as well as within
3060 Note that the code length returned includes the terminating whitespace
3061 character, which is always included in the regex match.
3064 code SMTP code, may involve extended status codes
3065 codelen length of smtp code; if > 4 there's an ESC
3067 log_msg optional log message, to be adjusted with the new SMTP code
3068 check_valid if true, verify the response code
3074 smtp_message_code(uschar **code, int *codelen, uschar **msg, uschar **log_msg,
3080 if (!msg || !*msg) return;
3082 if ((n = pcre_exec(regex_smtp_code, NULL, CS *msg, Ustrlen(*msg), 0,
3083 PCRE_EOPT, ovector, sizeof(ovector)/sizeof(int))) < 0) return;
3085 if (check_valid && (*msg)[0] != (*code)[0])
3087 log_write(0, LOG_MAIN|LOG_PANIC, "configured error code starts with "
3088 "incorrect digit (expected %c) in \"%s\"", (*code)[0], *msg);
3089 if (log_msg != NULL && *log_msg == *msg)
3090 *log_msg = string_sprintf("%s %s", *code, *log_msg + ovector[1]);
3095 *codelen = ovector[1]; /* Includes final space */
3097 *msg += ovector[1]; /* Chop the code off the message */
3104 /*************************************************
3105 * Handle an ACL failure *
3106 *************************************************/
3108 /* This function is called when acl_check() fails. As well as calls from within
3109 this module, it is called from receive.c for an ACL after DATA. It sorts out
3110 logging the incident, and sets up the error response. A message containing
3111 newlines is turned into a multiline SMTP response, but for logging, only the
3114 There's a table of default permanent failure response codes to use in
3115 globals.c, along with the table of names. VFRY is special. Despite RFC1123 it
3116 defaults disabled in Exim. However, discussion in connection with RFC 821bis
3117 (aka RFC 2821) has concluded that the response should be 252 in the disabled
3118 state, because there are broken clients that try VRFY before RCPT. A 5xx
3119 response should be given only when the address is positively known to be
3120 undeliverable. Sigh. We return 252 if there is no VRFY ACL or it provides
3121 no explicit code, but if there is one we let it know best.
3122 Also, for ETRN, 458 is given on refusal, and for AUTH, 503.
3124 From Exim 4.63, it is possible to override the response code details by
3125 providing a suitable response code string at the start of the message provided
3126 in user_msg. The code's first digit is checked for validity.
3129 where where the ACL was called from
3131 user_msg a message that can be included in an SMTP response
3132 log_msg a message for logging
3134 Returns: 0 in most cases
3135 2 if the failure code was FAIL_DROP, in which case the
3136 SMTP connection should be dropped (this value fits with the
3137 "done" variable in smtp_setup_msg() below)
3141 smtp_handle_acl_fail(int where, int rc, uschar *user_msg, uschar *log_msg)
3143 BOOL drop = rc == FAIL_DROP;
3147 uschar *sender_info = US"";
3149 #ifdef WITH_CONTENT_SCAN
3150 where == ACL_WHERE_MIME ? US"during MIME ACL checks" :
3152 where == ACL_WHERE_PREDATA ? US"DATA" :
3153 where == ACL_WHERE_DATA ? US"after DATA" :
3154 #ifndef DISABLE_PRDR
3155 where == ACL_WHERE_PRDR ? US"after DATA PRDR" :
3158 string_sprintf("%s %s", acl_wherenames[where], smtp_cmd_data) :
3159 string_sprintf("%s in \"connect\" ACL", acl_wherenames[where]);
3161 if (drop) rc = FAIL;
3163 /* Set the default SMTP code, and allow a user message to change it. */
3165 smtp_code = rc == FAIL ? acl_wherecodes[where] : US"451";
3166 smtp_message_code(&smtp_code, &codelen, &user_msg, &log_msg,
3167 where != ACL_WHERE_VRFY);
3169 /* We used to have sender_address here; however, there was a bug that was not
3170 updating sender_address after a rewrite during a verify. When this bug was
3171 fixed, sender_address at this point became the rewritten address. I'm not sure
3172 this is what should be logged, so I've changed to logging the unrewritten
3173 address to retain backward compatibility. */
3175 #ifndef WITH_CONTENT_SCAN
3176 if (where == ACL_WHERE_RCPT || where == ACL_WHERE_DATA)
3178 if (where == ACL_WHERE_RCPT || where == ACL_WHERE_DATA || where == ACL_WHERE_MIME)
3181 sender_info = string_sprintf("F=<%s>%s%s%s%s ",
3182 sender_address_unrewritten ? sender_address_unrewritten : sender_address,
3183 sender_host_authenticated ? US" A=" : US"",
3184 sender_host_authenticated ? sender_host_authenticated : US"",
3185 sender_host_authenticated && authenticated_id ? US":" : US"",
3186 sender_host_authenticated && authenticated_id ? authenticated_id : US""
3190 /* If there's been a sender verification failure with a specific message, and
3191 we have not sent a response about it yet, do so now, as a preliminary line for
3192 failures, but not defers. However, always log it for defer, and log it for fail
3193 unless the sender_verify_fail log selector has been turned off. */
3195 if (sender_verified_failed &&
3196 !testflag(sender_verified_failed, af_sverify_told))
3198 BOOL save_rcpt_in_progress = rcpt_in_progress;
3199 rcpt_in_progress = FALSE; /* So as not to treat these as the error */
3201 setflag(sender_verified_failed, af_sverify_told);
3203 if (rc != FAIL || LOGGING(sender_verify_fail))
3204 log_write(0, LOG_MAIN|LOG_REJECT, "%s sender verify %s for <%s>%s",
3205 host_and_ident(TRUE),
3206 ((sender_verified_failed->special_action & 255) == DEFER)? "defer":"fail",
3207 sender_verified_failed->address,
3208 (sender_verified_failed->message == NULL)? US"" :
3209 string_sprintf(": %s", sender_verified_failed->message));
3211 if (rc == FAIL && sender_verified_failed->user_message)
3212 smtp_respond(smtp_code, codelen, FALSE, string_sprintf(
3213 testflag(sender_verified_failed, af_verify_pmfail)?
3214 "Postmaster verification failed while checking <%s>\n%s\n"
3215 "Several RFCs state that you are required to have a postmaster\n"
3216 "mailbox for each mail domain. This host does not accept mail\n"
3217 "from domains whose servers reject the postmaster address."
3219 testflag(sender_verified_failed, af_verify_nsfail)?
3220 "Callback setup failed while verifying <%s>\n%s\n"
3221 "The initial connection, or a HELO or MAIL FROM:<> command was\n"
3222 "rejected. Refusing MAIL FROM:<> does not help fight spam, disregards\n"
3223 "RFC requirements, and stops you from receiving standard bounce\n"
3224 "messages. This host does not accept mail from domains whose servers\n"
3227 "Verification failed for <%s>\n%s",
3228 sender_verified_failed->address,
3229 sender_verified_failed->user_message));
3231 rcpt_in_progress = save_rcpt_in_progress;
3234 /* Sort out text for logging */
3236 log_msg = log_msg ? string_sprintf(": %s", log_msg) : US"";
3237 if ((lognl = Ustrchr(log_msg, '\n'))) *lognl = 0;
3239 /* Send permanent failure response to the command, but the code used isn't
3240 always a 5xx one - see comments at the start of this function. If the original
3241 rc was FAIL_DROP we drop the connection and yield 2. */
3244 smtp_respond(smtp_code, codelen, TRUE,
3245 user_msg ? user_msg : US"Administrative prohibition");
3247 /* Send temporary failure response to the command. Don't give any details,
3248 unless acl_temp_details is set. This is TRUE for a callout defer, a "defer"
3249 verb, and for a header verify when smtp_return_error_details is set.
3251 This conditional logic is all somewhat of a mess because of the odd
3252 interactions between temp_details and return_error_details. One day it should
3253 be re-implemented in a tidier fashion. */
3256 if (acl_temp_details && user_msg)
3258 if ( smtp_return_error_details
3259 && sender_verified_failed
3260 && sender_verified_failed->message
3262 smtp_respond(smtp_code, codelen, FALSE, sender_verified_failed->message);
3264 smtp_respond(smtp_code, codelen, TRUE, user_msg);
3267 smtp_respond(smtp_code, codelen, TRUE,
3268 US"Temporary local problem - please try later");
3270 /* Log the incident to the logs that are specified by log_reject_target
3271 (default main, reject). This can be empty to suppress logging of rejections. If
3272 the connection is not forcibly to be dropped, return 0. Otherwise, log why it
3273 is closing if required and return 2. */
3275 if (log_reject_target != 0)
3278 uschar * tls = s_tlslog(NULL, NULL, NULL);
3279 if (!tls) tls = US"";
3281 uschar * tls = US"";
3283 log_write(where == ACL_WHERE_CONNECT ? L_connection_reject : 0,
3284 log_reject_target, "%s%s%s %s%srejected %s%s",
3285 LOGGING(dnssec) && sender_host_dnssec ? US" DS" : US"",
3286 host_and_ident(TRUE),
3289 rc == FAIL ? US"" : US"temporarily ",
3293 if (!drop) return 0;
3295 log_write(L_smtp_connection, LOG_MAIN, "%s closed by DROP in ACL",
3296 smtp_get_connection_info());
3298 /* Run the not-quit ACL, but without any custom messages. This should not be a
3299 problem, because we get here only if some other ACL has issued "drop", and
3300 in that case, *its* custom messages will have been used above. */
3302 smtp_notquit_exit(US"acl-drop", NULL, NULL);
3309 /*************************************************
3310 * Handle SMTP exit when QUIT is not given *
3311 *************************************************/
3313 /* This function provides a logging/statistics hook for when an SMTP connection
3314 is dropped on the floor or the other end goes away. It's a global function
3315 because it's called from receive.c as well as this module. As well as running
3316 the NOTQUIT ACL, if there is one, this function also outputs a final SMTP
3317 response, either with a custom message from the ACL, or using a default. There
3318 is one case, however, when no message is output - after "drop". In that case,
3319 the ACL that obeyed "drop" has already supplied the custom message, and NULL is
3320 passed to this function.
3322 In case things go wrong while processing this function, causing an error that
3323 may re-enter this function, there is a recursion check.
3326 reason What $smtp_notquit_reason will be set to in the ACL;
3327 if NULL, the ACL is not run
3328 code The error code to return as part of the response
3329 defaultrespond The default message if there's no user_msg
3335 smtp_notquit_exit(uschar *reason, uschar *code, uschar *defaultrespond, ...)
3338 uschar *user_msg = NULL;
3339 uschar *log_msg = NULL;
3341 /* Check for recursive acll */
3343 if (smtp_exit_function_called)
3345 log_write(0, LOG_PANIC, "smtp_notquit_exit() called more than once (%s)",
3349 smtp_exit_function_called = TRUE;
3351 /* Call the not-QUIT ACL, if there is one, unless no reason is given. */
3353 if (acl_smtp_notquit && reason)
3355 smtp_notquit_reason = reason;
3356 if ((rc = acl_check(ACL_WHERE_NOTQUIT, NULL, acl_smtp_notquit, &user_msg,
3357 &log_msg)) == ERROR)
3358 log_write(0, LOG_MAIN|LOG_PANIC, "ACL for not-QUIT returned ERROR: %s",
3362 /* Write an SMTP response if we are expected to give one. As the default
3363 responses are all internal, they should always fit in the buffer, but code a
3364 warning, just in case. Note that string_vformat() still leaves a complete
3365 string, even if it is incomplete. */
3367 if (code && defaultrespond)
3370 smtp_respond(code, 3, TRUE, user_msg);
3375 va_start(ap, defaultrespond);
3376 if (!string_vformat(buffer, sizeof(buffer), CS defaultrespond, ap))
3377 log_write(0, LOG_MAIN|LOG_PANIC, "string too large in smtp_notquit_exit()");
3378 smtp_printf("%s %s\r\n", FALSE, code, buffer);
3388 /*************************************************
3389 * Verify HELO argument *
3390 *************************************************/
3392 /* This function is called if helo_verify_hosts or helo_try_verify_hosts is
3393 matched. It is also called from ACL processing if verify = helo is used and
3394 verification was not previously tried (i.e. helo_try_verify_hosts was not
3395 matched). The result of its processing is to set helo_verified and
3396 helo_verify_failed. These variables should both be FALSE for this function to
3399 Note that EHLO/HELO is legitimately allowed to quote an address literal. Allow
3400 for IPv6 ::ffff: literals.
3403 Returns: TRUE if testing was completed;
3404 FALSE on a temporary failure
3408 smtp_verify_helo(void)
3412 HDEBUG(D_receive) debug_printf("verifying EHLO/HELO argument \"%s\"\n",
3415 if (sender_helo_name == NULL)
3417 HDEBUG(D_receive) debug_printf("no EHLO/HELO command was issued\n");
3420 /* Deal with the case of -bs without an IP address */
3422 else if (sender_host_address == NULL)
3424 HDEBUG(D_receive) debug_printf("no client IP address: assume success\n");
3425 helo_verified = TRUE;
3428 /* Deal with the more common case when there is a sending IP address */
3430 else if (sender_helo_name[0] == '[')
3432 helo_verified = Ustrncmp(sender_helo_name+1, sender_host_address,
3433 Ustrlen(sender_host_address)) == 0;
3438 if (strncmpic(sender_host_address, US"::ffff:", 7) == 0)
3439 helo_verified = Ustrncmp(sender_helo_name + 1,
3440 sender_host_address + 7, Ustrlen(sender_host_address) - 7) == 0;
3445 { if (helo_verified) debug_printf("matched host address\n"); }
3448 /* Do a reverse lookup if one hasn't already given a positive or negative
3449 response. If that fails, or the name doesn't match, try checking with a forward
3454 if (sender_host_name == NULL && !host_lookup_failed)
3455 yield = host_name_lookup() != DEFER;
3457 /* If a host name is known, check it and all its aliases. */
3459 if (sender_host_name)
3460 if ((helo_verified = strcmpic(sender_host_name, sender_helo_name) == 0))
3462 sender_helo_dnssec = sender_host_dnssec;
3463 HDEBUG(D_receive) debug_printf("matched host name\n");
3467 uschar **aliases = sender_host_aliases;
3469 if ((helo_verified = strcmpic(*aliases++, sender_helo_name) == 0))
3471 sender_helo_dnssec = sender_host_dnssec;
3475 HDEBUG(D_receive) if (helo_verified)
3476 debug_printf("matched alias %s\n", *(--aliases));
3479 /* Final attempt: try a forward lookup of the helo name */
3488 h.name = sender_helo_name;
3495 HDEBUG(D_receive) debug_printf("getting IP address for %s\n",
3497 rc = host_find_bydns(&h, NULL, HOST_FIND_BY_A,
3498 NULL, NULL, NULL, &d, NULL, NULL);
3499 if (rc == HOST_FOUND || rc == HOST_FOUND_LOCAL)
3500 for (hh = &h; hh; hh = hh->next)
3501 if (Ustrcmp(hh->address, sender_host_address) == 0)
3503 helo_verified = TRUE;
3504 if (h.dnssec == DS_YES) sender_helo_dnssec = TRUE;
3507 debug_printf("IP address for %s matches calling address\n"
3508 "Forward DNS security status: %sverified\n",
3509 sender_helo_name, sender_helo_dnssec ? "" : "un");
3516 if (!helo_verified) helo_verify_failed = TRUE; /* We've tried ... */
3523 /*************************************************
3524 * Send user response message *
3525 *************************************************/
3527 /* This function is passed a default response code and a user message. It calls
3528 smtp_message_code() to check and possibly modify the response code, and then
3529 calls smtp_respond() to transmit the response. I put this into a function
3530 just to avoid a lot of repetition.
3533 code the response code
3534 user_msg the user message
3540 smtp_user_msg(uschar *code, uschar *user_msg)
3543 smtp_message_code(&code, &len, &user_msg, NULL, TRUE);
3544 smtp_respond(code, len, TRUE, user_msg);
3550 smtp_in_auth(auth_instance *au, uschar ** s, uschar ** ss)
3552 const uschar *set_id = NULL;
3555 /* Run the checking code, passing the remainder of the command line as
3556 data. Initials the $auth<n> variables as empty. Initialize $0 empty and set
3557 it as the only set numerical variable. The authenticator may set $auth<n>
3558 and also set other numeric variables. The $auth<n> variables are preferred
3559 nowadays; the numerical variables remain for backwards compatibility.
3561 Afterwards, have a go at expanding the set_id string, even if
3562 authentication failed - for bad passwords it can be useful to log the
3563 userid. On success, require set_id to expand and exist, and put it in
3564 authenticated_id. Save this in permanent store, as the working store gets
3565 reset at HELO, RSET, etc. */
3567 for (i = 0; i < AUTH_VARS; i++) auth_vars[i] = NULL;
3569 expand_nlength[0] = 0; /* $0 contains nothing */
3571 rc = (au->info->servercode)(au, smtp_cmd_data);
3572 if (au->set_id) set_id = expand_string(au->set_id);
3573 expand_nmax = -1; /* Reset numeric variables */
3574 for (i = 0; i < AUTH_VARS; i++) auth_vars[i] = NULL; /* Reset $auth<n> */
3576 /* The value of authenticated_id is stored in the spool file and printed in
3577 log lines. It must not contain binary zeros or newline characters. In
3578 normal use, it never will, but when playing around or testing, this error
3579 can (did) happen. To guard against this, ensure that the id contains only
3580 printing characters. */
3582 if (set_id) set_id = string_printing(set_id);
3584 /* For the non-OK cases, set up additional logging data if set_id
3588 set_id = set_id && *set_id
3589 ? string_sprintf(" (set_id=%s)", set_id) : US"";
3591 /* Switch on the result */
3596 if (!au->set_id || set_id) /* Complete success */
3598 if (set_id) authenticated_id = string_copy_malloc(set_id);
3599 sender_host_authenticated = au->name;
3600 authentication_failed = FALSE;
3601 authenticated_fail_id = NULL; /* Impossible to already be set? */
3604 (sender_host_address ? protocols : protocols_local)
3605 [pextend + pauthed + (tls_in.active >= 0 ? pcrpted:0)];
3606 *s = *ss = US"235 Authentication succeeded";
3607 authenticated_by = au;
3611 /* Authentication succeeded, but we failed to expand the set_id string.
3612 Treat this as a temporary error. */
3614 auth_defer_msg = expand_string_message;
3618 if (set_id) authenticated_fail_id = string_copy_malloc(set_id);
3619 *s = string_sprintf("435 Unable to authenticate at present%s",
3620 auth_defer_user_msg);
3621 *ss = string_sprintf("435 Unable to authenticate at present%s: %s",
3622 set_id, auth_defer_msg);
3626 *s = *ss = US"501 Invalid base64 data";
3630 *s = *ss = US"501 Authentication cancelled";
3634 *s = *ss = US"553 Initial data not expected";
3638 if (set_id) authenticated_fail_id = string_copy_malloc(set_id);
3639 *s = US"535 Incorrect authentication data";
3640 *ss = string_sprintf("535 Incorrect authentication data%s", set_id);
3644 if (set_id) authenticated_fail_id = string_copy_malloc(set_id);
3645 *s = US"435 Internal error";
3646 *ss = string_sprintf("435 Internal error%s: return %d from authentication "
3647 "check", set_id, rc);
3659 qualify_recipient(uschar ** recipient, uschar * smtp_cmd_data, uschar * tag)
3662 if (allow_unqualified_recipient || strcmpic(*recipient, US"postmaster") == 0)
3664 DEBUG(D_receive) debug_printf("unqualified address %s accepted\n",
3666 rd = Ustrlen(recipient) + 1;
3667 *recipient = rewrite_address_qualify(*recipient, TRUE);
3670 smtp_printf("501 %s: recipient address must contain a domain\r\n", FALSE,
3672 log_write(L_smtp_syntax_error,
3673 LOG_MAIN|LOG_REJECT, "unqualified %s rejected: <%s> %s%s",
3674 tag, *recipient, host_and_ident(TRUE), host_lookup_msg);
3682 smtp_quit_handler(uschar ** user_msgp, uschar ** log_msgp)
3685 incomplete_transaction_log(US"QUIT");
3688 int rc = acl_check(ACL_WHERE_QUIT, NULL, acl_smtp_quit, user_msgp, log_msgp);
3690 log_write(0, LOG_MAIN|LOG_PANIC, "ACL for QUIT returned ERROR: %s",
3694 smtp_respond(US"221", 3, TRUE, *user_msgp);
3696 smtp_printf("221 %s closing connection\r\n", FALSE, smtp_active_hostname);
3699 tls_close(TRUE, TRUE);
3702 log_write(L_smtp_connection, LOG_MAIN, "%s closed by QUIT",
3703 smtp_get_connection_info());
3708 smtp_rset_handler(void)
3711 incomplete_transaction_log(US"RSET");
3712 smtp_printf("250 Reset OK\r\n", FALSE);
3713 cmd_list[CMD_LIST_RSET].is_mail_cmd = FALSE;
3718 /*************************************************
3719 * Initialize for SMTP incoming message *
3720 *************************************************/
3722 /* This function conducts the initial dialogue at the start of an incoming SMTP
3723 message, and builds a list of recipients. However, if the incoming message
3724 is part of a batch (-bS option) a separate function is called since it would
3725 be messy having tests splattered about all over this function. This function
3726 therefore handles the case where interaction is occurring. The input and output
3727 files are set up in smtp_in and smtp_out.
3729 The global recipients_list is set to point to a vector of recipient_item
3730 blocks, whose number is given by recipients_count. This is extended by the
3731 receive_add_recipient() function. The global variable sender_address is set to
3732 the sender's address. The yield is +1 if a message has been successfully
3733 started, 0 if a QUIT command was encountered or the connection was refused from
3734 the particular host, or -1 if the connection was lost.
3738 Returns: > 0 message successfully started (reached DATA)
3739 = 0 QUIT read or end of file reached or call refused
3744 smtp_setup_msg(void)
3747 BOOL toomany = FALSE;
3748 BOOL discarded = FALSE;
3749 BOOL last_was_rej_mail = FALSE;
3750 BOOL last_was_rcpt = FALSE;
3751 void *reset_point = store_get(0);
3753 DEBUG(D_receive) debug_printf("smtp_setup_msg entered\n");
3755 /* Reset for start of new message. We allow one RSET not to be counted as a
3756 nonmail command, for those MTAs that insist on sending it between every
3757 message. Ditto for EHLO/HELO and for STARTTLS, to allow for going in and out of
3758 TLS between messages (an Exim client may do this if it has messages queued up
3759 for the host). Note: we do NOT reset AUTH at this point. */
3761 smtp_reset(reset_point);
3762 message_ended = END_NOTSTARTED;
3764 chunking_state = chunking_offered ? CHUNKING_OFFERED : CHUNKING_NOT_OFFERED;
3766 cmd_list[CMD_LIST_RSET].is_mail_cmd = TRUE;
3767 cmd_list[CMD_LIST_HELO].is_mail_cmd = TRUE;
3768 cmd_list[CMD_LIST_EHLO].is_mail_cmd = TRUE;
3770 cmd_list[CMD_LIST_STARTTLS].is_mail_cmd = TRUE;
3771 cmd_list[CMD_LIST_TLS_AUTH].is_mail_cmd = TRUE;
3774 /* Set the local signal handler for SIGTERM - it tries to end off tidily */
3776 os_non_restarting_signal(SIGTERM, command_sigterm_handler);
3778 /* Batched SMTP is handled in a different function. */
3780 if (smtp_batched_input) return smtp_setup_batch_msg();
3782 /* Deal with SMTP commands. This loop is exited by setting done to a POSITIVE
3783 value. The values are 2 larger than the required yield of the function. */
3787 const uschar **argv;
3788 uschar *etrn_command;
3789 uschar *etrn_serialize_key;
3791 uschar *log_msg, *smtp_code;
3792 uschar *user_msg = NULL;
3793 uschar *recipient = NULL;
3794 uschar *hello = NULL;
3796 BOOL was_rej_mail = FALSE;
3797 BOOL was_rcpt = FALSE;
3798 void (*oldsignal)(int);
3800 int start, end, sender_domain, recipient_domain;
3804 uschar *orcpt = NULL;
3808 /* Check once per STARTTLS or SSL-on-connect for a TLS AUTH */
3809 if ( tls_in.active >= 0
3811 && tls_in.certificate_verified
3812 && cmd_list[CMD_LIST_TLS_AUTH].is_mail_cmd
3815 cmd_list[CMD_LIST_TLS_AUTH].is_mail_cmd = FALSE;
3817 && (rc = acl_check(ACL_WHERE_AUTH, NULL, acl_smtp_auth,
3818 &user_msg, &log_msg)) != OK
3821 done = smtp_handle_acl_fail(ACL_WHERE_AUTH, rc, user_msg, log_msg);
3825 for (au = auths; au; au = au->next)
3826 if (strcmpic(US"tls", au->driver_name) == 0)
3828 smtp_cmd_data = NULL;
3830 if (smtp_in_auth(au, &s, &ss) == OK)
3831 { DEBUG(D_auth) debug_printf("tls auth succeeded\n"); }
3833 { DEBUG(D_auth) debug_printf("tls auth not succeeded\n"); }
3840 if (smtp_in) /* Avoid pure-ACKs while in cmd pingpong phase */
3841 (void) setsockopt(fileno(smtp_in), IPPROTO_TCP, TCP_QUICKACK,
3842 US &off, sizeof(off));
3845 switch(smtp_read_command(TRUE, GETC_BUFFER_UNLIMITED))
3847 /* The AUTH command is not permitted to occur inside a transaction, and may
3848 occur successfully only once per connection. Actually, that isn't quite
3849 true. When TLS is started, all previous information about a connection must
3850 be discarded, so a new AUTH is permitted at that time.
3852 AUTH may only be used when it has been advertised. However, it seems that
3853 there are clients that send AUTH when it hasn't been advertised, some of
3854 them even doing this after HELO. And there are MTAs that accept this. Sigh.
3855 So there's a get-out that allows this to happen.
3857 AUTH is initially labelled as a "nonmail command" so that one occurrence
3858 doesn't get counted. We change the label here so that multiple failing
3859 AUTHS will eventually hit the nonmail threshold. */
3863 authentication_failed = TRUE;
3864 cmd_list[CMD_LIST_AUTH].is_mail_cmd = FALSE;
3866 if (!auth_advertised && !allow_auth_unadvertised)
3868 done = synprot_error(L_smtp_protocol_error, 503, NULL,
3869 US"AUTH command used when not advertised");
3872 if (sender_host_authenticated)
3874 done = synprot_error(L_smtp_protocol_error, 503, NULL,
3875 US"already authenticated");
3880 done = synprot_error(L_smtp_protocol_error, 503, NULL,
3881 US"not permitted in mail transaction");
3888 && (rc = acl_check(ACL_WHERE_AUTH, NULL, acl_smtp_auth,
3889 &user_msg, &log_msg)) != OK
3892 done = smtp_handle_acl_fail(ACL_WHERE_AUTH, rc, user_msg, log_msg);
3896 /* Find the name of the requested authentication mechanism. */
3899 while ((c = *smtp_cmd_data) != 0 && !isspace(c))
3901 if (!isalnum(c) && c != '-' && c != '_')
3903 done = synprot_error(L_smtp_syntax_error, 501, NULL,
3904 US"invalid character in authentication mechanism name");
3910 /* If not at the end of the line, we must be at white space. Terminate the
3911 name and move the pointer on to any data that may be present. */
3913 if (*smtp_cmd_data != 0)
3915 *smtp_cmd_data++ = 0;
3916 while (isspace(*smtp_cmd_data)) smtp_cmd_data++;
3919 /* Search for an authentication mechanism which is configured for use
3920 as a server and which has been advertised (unless, sigh, allow_auth_
3921 unadvertised is set). */
3923 for (au = auths; au; au = au->next)
3924 if (strcmpic(s, au->public_name) == 0 && au->server &&
3925 (au->advertised || allow_auth_unadvertised))
3930 c = smtp_in_auth(au, &s, &ss);
3932 smtp_printf("%s\r\n", FALSE, s);
3934 log_write(0, LOG_MAIN|LOG_REJECT, "%s authenticator failed for %s: %s",
3935 au->name, host_and_ident(FALSE), ss);
3938 done = synprot_error(L_smtp_protocol_error, 504, NULL,
3939 string_sprintf("%s authentication mechanism not supported", s));
3941 break; /* AUTH_CMD */
3943 /* The HELO/EHLO commands are permitted to appear in the middle of a
3944 session as well as at the beginning. They have the effect of a reset in
3945 addition to their other functions. Their absence at the start cannot be
3946 taken to be an error.
3950 If the EHLO command is not acceptable to the SMTP server, 501, 500,
3951 or 502 failure replies MUST be returned as appropriate. The SMTP
3952 server MUST stay in the same state after transmitting these replies
3953 that it was in before the EHLO was received.
3955 Therefore, we do not do the reset until after checking the command for
3956 acceptability. This change was made for Exim release 4.11. Previously
3957 it did the reset first. */
3970 HELO_EHLO: /* Common code for HELO and EHLO */
3971 cmd_list[CMD_LIST_HELO].is_mail_cmd = FALSE;
3972 cmd_list[CMD_LIST_EHLO].is_mail_cmd = FALSE;
3974 /* Reject the HELO if its argument was invalid or non-existent. A
3975 successful check causes the argument to be saved in malloc store. */
3977 if (!check_helo(smtp_cmd_data))
3979 smtp_printf("501 Syntactically invalid %s argument(s)\r\n", FALSE, hello);
3981 log_write(0, LOG_MAIN|LOG_REJECT, "rejected %s from %s: syntactically "
3982 "invalid argument(s): %s", hello, host_and_ident(FALSE),
3983 (*smtp_cmd_argument == 0)? US"(no argument given)" :
3984 string_printing(smtp_cmd_argument));
3986 if (++synprot_error_count > smtp_max_synprot_errors)
3988 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
3989 "syntax or protocol errors (last command was \"%s\")",
3990 host_and_ident(FALSE), string_printing(smtp_cmd_buffer));
3997 /* If sender_host_unknown is true, we have got here via the -bs interface,
3998 not called from inetd. Otherwise, we are running an IP connection and the
3999 host address will be set. If the helo name is the primary name of this
4000 host and we haven't done a reverse lookup, force one now. If helo_required
4001 is set, ensure that the HELO name matches the actual host. If helo_verify
4002 is set, do the same check, but softly. */
4004 if (!sender_host_unknown)
4006 BOOL old_helo_verified = helo_verified;
4007 uschar *p = smtp_cmd_data;
4009 while (*p != 0 && !isspace(*p)) { *p = tolower(*p); p++; }
4012 /* Force a reverse lookup if HELO quoted something in helo_lookup_domains
4013 because otherwise the log can be confusing. */
4015 if (sender_host_name == NULL &&
4016 (deliver_domain = sender_helo_name, /* set $domain */
4017 match_isinlist(sender_helo_name, CUSS &helo_lookup_domains, 0,
4018 &domainlist_anchor, NULL, MCL_DOMAIN, TRUE, NULL)) == OK)
4019 (void)host_name_lookup();
4021 /* Rebuild the fullhost info to include the HELO name (and the real name
4022 if it was looked up.) */
4024 host_build_sender_fullhost(); /* Rebuild */
4025 set_process_info("handling%s incoming connection from %s",
4026 (tls_in.active >= 0)? " TLS" : "", host_and_ident(FALSE));
4028 /* Verify if configured. This doesn't give much security, but it does
4029 make some people happy to be able to do it. If helo_required is set,
4030 (host matches helo_verify_hosts) failure forces rejection. If helo_verify
4031 is set (host matches helo_try_verify_hosts), it does not. This is perhaps
4032 now obsolescent, since the verification can now be requested selectively
4035 helo_verified = helo_verify_failed = sender_helo_dnssec = FALSE;
4036 if (helo_required || helo_verify)
4038 BOOL tempfail = !smtp_verify_helo();
4043 smtp_printf("%d %s argument does not match calling host\r\n", FALSE,
4044 tempfail? 451 : 550, hello);
4045 log_write(0, LOG_MAIN|LOG_REJECT, "%srejected \"%s %s\" from %s",
4046 tempfail? "temporarily " : "",
4047 hello, sender_helo_name, host_and_ident(FALSE));
4048 helo_verified = old_helo_verified;
4049 break; /* End of HELO/EHLO processing */
4051 HDEBUG(D_all) debug_printf("%s verification failed but host is in "
4052 "helo_try_verify_hosts\n", hello);
4057 #ifdef EXPERIMENTAL_SPF
4058 /* set up SPF context */
4059 spf_init(sender_helo_name, sender_host_address);
4062 /* Apply an ACL check if one is defined; afterwards, recheck
4063 synchronization in case the client started sending in a delay. */
4066 if ((rc = acl_check(ACL_WHERE_HELO, NULL, acl_smtp_helo,
4067 &user_msg, &log_msg)) != OK)
4069 done = smtp_handle_acl_fail(ACL_WHERE_HELO, rc, user_msg, log_msg);
4070 sender_helo_name = NULL;
4071 host_build_sender_fullhost(); /* Rebuild */
4074 else if (!check_sync()) goto SYNC_FAILURE;
4076 /* Generate an OK reply. The default string includes the ident if present,
4077 and also the IP address if present. Reflecting back the ident is intended
4078 as a deterrent to mail forgers. For maximum efficiency, and also because
4079 some broken systems expect each response to be in a single packet, arrange
4080 that the entire reply is sent in one write(). */
4082 auth_advertised = FALSE;
4083 pipelining_advertised = FALSE;
4085 tls_advertised = FALSE;
4087 dsn_advertised = FALSE;
4089 smtputf8_advertised = FALSE;
4092 smtp_code = US"250 "; /* Default response code plus space*/
4095 s = string_sprintf("%.3s %s Hello %s%s%s",
4097 smtp_active_hostname,
4098 sender_ident ? sender_ident : US"",
4099 sender_ident ? US" at " : US"",
4100 sender_host_name ? sender_host_name : sender_helo_name);
4105 if (sender_host_address)
4107 s = string_catn(s, &size, &ptr, US" [", 2);
4108 s = string_cat (s, &size, &ptr, sender_host_address);
4109 s = string_catn(s, &size, &ptr, US"]", 1);
4113 /* A user-supplied EHLO greeting may not contain more than one line. Note
4114 that the code returned by smtp_message_code() includes the terminating
4115 whitespace character. */
4121 smtp_message_code(&smtp_code, &codelen, &user_msg, NULL, TRUE);
4122 s = string_sprintf("%.*s%s", codelen, smtp_code, user_msg);
4123 if ((ss = strpbrk(CS s, "\r\n")) != NULL)
4125 log_write(0, LOG_MAIN|LOG_PANIC, "EHLO/HELO response must not contain "
4126 "newlines: message truncated: %s", string_printing(s));
4133 s = string_catn(s, &size, &ptr, US"\r\n", 2);
4135 /* If we received EHLO, we must create a multiline response which includes
4136 the functions supported. */
4142 /* I'm not entirely happy with this, as an MTA is supposed to check
4143 that it has enough room to accept a message of maximum size before
4144 it sends this. However, there seems little point in not sending it.
4145 The actual size check happens later at MAIL FROM time. By postponing it
4146 till then, VRFY and EXPN can be used after EHLO when space is short. */
4148 if (thismessage_size_limit > 0)
4150 sprintf(CS big_buffer, "%.3s-SIZE %d\r\n", smtp_code,
4151 thismessage_size_limit);
4152 s = string_cat(s, &size, &ptr, big_buffer);
4156 s = string_catn(s, &size, &ptr, smtp_code, 3);
4157 s = string_catn(s, &size, &ptr, US"-SIZE\r\n", 7);
4160 /* Exim does not do protocol conversion or data conversion. It is 8-bit
4161 clean; if it has an 8-bit character in its hand, it just sends it. It
4162 cannot therefore specify 8BITMIME and remain consistent with the RFCs.
4163 However, some users want this option simply in order to stop MUAs
4164 mangling messages that contain top-bit-set characters. It is therefore
4165 provided as an option. */
4167 if (accept_8bitmime)
4169 s = string_catn(s, &size, &ptr, smtp_code, 3);
4170 s = string_catn(s, &size, &ptr, US"-8BITMIME\r\n", 11);
4173 /* Advertise DSN support if configured to do so. */
4174 if (verify_check_host(&dsn_advertise_hosts) != FAIL)
4176 s = string_catn(s, &size, &ptr, smtp_code, 3);
4177 s = string_catn(s, &size, &ptr, US"-DSN\r\n", 6);
4178 dsn_advertised = TRUE;
4181 /* Advertise ETRN/VRFY/EXPN if there's are ACL checking whether a host is
4182 permitted to issue them; a check is made when any host actually tries. */
4186 s = string_catn(s, &size, &ptr, smtp_code, 3);
4187 s = string_catn(s, &size, &ptr, US"-ETRN\r\n", 7);
4191 s = string_catn(s, &size, &ptr, smtp_code, 3);
4192 s = string_catn(s, &size, &ptr, US"-VRFY\r\n", 7);
4196 s = string_catn(s, &size, &ptr, smtp_code, 3);
4197 s = string_catn(s, &size, &ptr, US"-EXPN\r\n", 7);
4200 /* Exim is quite happy with pipelining, so let the other end know that
4201 it is safe to use it, unless advertising is disabled. */
4203 if (pipelining_enable &&
4204 verify_check_host(&pipelining_advertise_hosts) == OK)
4206 s = string_catn(s, &size, &ptr, smtp_code, 3);
4207 s = string_catn(s, &size, &ptr, US"-PIPELINING\r\n", 13);
4208 sync_cmd_limit = NON_SYNC_CMD_PIPELINING;
4209 pipelining_advertised = TRUE;
4213 /* If any server authentication mechanisms are configured, advertise
4214 them if the current host is in auth_advertise_hosts. The problem with
4215 advertising always is that some clients then require users to
4216 authenticate (and aren't configurable otherwise) even though it may not
4217 be necessary (e.g. if the host is in host_accept_relay).
4219 RFC 2222 states that SASL mechanism names contain only upper case
4220 letters, so output the names in upper case, though we actually recognize
4221 them in either case in the AUTH command. */
4225 && !sender_host_authenticated
4227 && verify_check_host(&auth_advertise_hosts) == OK
4232 for (au = auths; au; au = au->next)
4234 au->advertised = FALSE;
4237 DEBUG(D_auth+D_expand) debug_printf_indent(
4238 "Evaluating advertise_condition for %s athenticator\n",
4240 if ( !au->advertise_condition
4241 || expand_check_condition(au->advertise_condition, au->name,
4248 s = string_catn(s, &size, &ptr, smtp_code, 3);
4249 s = string_catn(s, &size, &ptr, US"-AUTH", 5);
4251 auth_advertised = TRUE;
4254 s = string_catn(s, &size, &ptr, US" ", 1);
4255 s = string_cat (s, &size, &ptr, au->public_name);
4256 while (++saveptr < ptr) s[saveptr] = toupper(s[saveptr]);
4257 au->advertised = TRUE;
4262 if (!first) s = string_catn(s, &size, &ptr, US"\r\n", 2);
4265 /* RFC 3030 CHUNKING */
4267 if (verify_check_host(&chunking_advertise_hosts) != FAIL)
4269 s = string_catn(s, &size, &ptr, smtp_code, 3);
4270 s = string_catn(s, &size, &ptr, US"-CHUNKING\r\n", 11);
4271 chunking_offered = TRUE;
4272 chunking_state = CHUNKING_OFFERED;
4275 /* Advertise TLS (Transport Level Security) aka SSL (Secure Socket Layer)
4276 if it has been included in the binary, and the host matches
4277 tls_advertise_hosts. We must *not* advertise if we are already in a
4278 secure connection. */
4281 if (tls_in.active < 0 &&
4282 verify_check_host(&tls_advertise_hosts) != FAIL)
4284 s = string_catn(s, &size, &ptr, smtp_code, 3);
4285 s = string_catn(s, &size, &ptr, US"-STARTTLS\r\n", 11);
4286 tls_advertised = TRUE;
4290 #ifndef DISABLE_PRDR
4291 /* Per Recipient Data Response, draft by Eric A. Hall extending RFC */
4294 s = string_catn(s, &size, &ptr, smtp_code, 3);
4295 s = string_catn(s, &size, &ptr, US"-PRDR\r\n", 7);
4300 if ( accept_8bitmime
4301 && verify_check_host(&smtputf8_advertise_hosts) != FAIL)
4303 s = string_catn(s, &size, &ptr, smtp_code, 3);
4304 s = string_catn(s, &size, &ptr, US"-SMTPUTF8\r\n", 11);
4305 smtputf8_advertised = TRUE;
4309 /* Finish off the multiline reply with one that is always available. */
4311 s = string_catn(s, &size, &ptr, smtp_code, 3);
4312 s = string_catn(s, &size, &ptr, US" HELP\r\n", 7);
4315 /* Terminate the string (for debug), write it, and note that HELO/EHLO
4321 if (tls_in.active >= 0) (void)tls_write(TRUE, s, ptr, FALSE); else
4325 int i = fwrite(s, 1, ptr, smtp_out); i = i; /* compiler quietening */
4330 while ((cr = Ustrchr(s, '\r')) != NULL) /* lose CRs */
4331 memmove(cr, cr + 1, (ptr--) - (cr - s));
4332 debug_printf("SMTP>> %s", s);
4336 /* Reset the protocol and the state, abandoning any previous message. */
4338 (sender_host_address ? protocols : protocols_local)
4340 ? pextend + (sender_host_authenticated ? pauthed : 0)
4342 + (tls_in.active >= 0 ? pcrpted : 0)
4344 cancel_cutthrough_connection(TRUE, US"sent EHLO response");
4345 smtp_reset(reset_point);
4347 break; /* HELO/EHLO */
4350 /* The MAIL command requires an address as an operand. All we do
4351 here is to parse it for syntactic correctness. The form "<>" is
4352 a special case which converts into an empty string. The start/end
4353 pointers in the original are not used further for this address, as
4354 it is the canonical extracted address which is all that is kept. */
4358 smtp_mailcmd_count++; /* Count for limit and ratelimit */
4359 was_rej_mail = TRUE; /* Reset if accepted */
4360 env_mail_type_t * mail_args; /* Sanity check & validate args */
4362 if (helo_required && !helo_seen)
4364 smtp_printf("503 HELO or EHLO required\r\n", FALSE);
4365 log_write(0, LOG_MAIN|LOG_REJECT, "rejected MAIL from %s: no "
4366 "HELO/EHLO given", host_and_ident(FALSE));
4370 if (sender_address != NULL)
4372 done = synprot_error(L_smtp_protocol_error, 503, NULL,
4373 US"sender already given");
4377 if (smtp_cmd_data[0] == 0)
4379 done = synprot_error(L_smtp_protocol_error, 501, NULL,
4380 US"MAIL must have an address operand");
4384 /* Check to see if the limit for messages per connection would be
4385 exceeded by accepting further messages. */
4387 if (smtp_accept_max_per_connection > 0 &&
4388 smtp_mailcmd_count > smtp_accept_max_per_connection)
4390 smtp_printf("421 too many messages in this connection\r\n", FALSE);
4391 log_write(0, LOG_MAIN|LOG_REJECT, "rejected MAIL command %s: too many "
4392 "messages in one connection", host_and_ident(TRUE));
4396 /* Reset for start of message - even if this is going to fail, we
4397 obviously need to throw away any previous data. */
4399 cancel_cutthrough_connection(TRUE, US"MAIL received");
4400 smtp_reset(reset_point);
4402 sender_data = recipient_data = NULL;
4404 /* Loop, checking for ESMTP additions to the MAIL FROM command. */
4408 uschar *name, *value, *end;
4409 unsigned long int size;
4410 BOOL arg_error = FALSE;
4412 if (!extract_option(&name, &value)) break;
4414 for (mail_args = env_mail_type_list;
4415 mail_args->value != ENV_MAIL_OPT_NULL;
4418 if (strcmpic(name, mail_args->name) == 0)
4420 if (mail_args->need_value && strcmpic(value, US"") == 0)
4423 switch(mail_args->value)
4425 /* Handle SIZE= by reading the value. We don't do the check till later,
4426 in order to be able to log the sender address on failure. */
4427 case ENV_MAIL_OPT_SIZE:
4428 if (((size = Ustrtoul(value, &end, 10)), *end == 0))
4430 if ((size == ULONG_MAX && errno == ERANGE) || size > INT_MAX)
4432 message_size = (int)size;
4438 /* If this session was initiated with EHLO and accept_8bitmime is set,
4439 Exim will have indicated that it supports the BODY=8BITMIME option. In
4440 fact, it does not support this according to the RFCs, in that it does not
4441 take any special action for forwarding messages containing 8-bit
4442 characters. That is why accept_8bitmime is not the default setting, but
4443 some sites want the action that is provided. We recognize both "8BITMIME"
4444 and "7BIT" as body types, but take no action. */
4445 case ENV_MAIL_OPT_BODY:
4446 if (accept_8bitmime) {
4447 if (strcmpic(value, US"8BITMIME") == 0)
4449 else if (strcmpic(value, US"7BIT") == 0)
4454 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4455 US"invalid data for BODY");
4458 DEBUG(D_receive) debug_printf("8BITMIME: %d\n", body_8bitmime);
4464 /* Handle the two DSN options, but only if configured to do so (which
4465 will have caused "DSN" to be given in the EHLO response). The code itself
4466 is included only if configured in at build time. */
4468 case ENV_MAIL_OPT_RET:
4471 /* Check if RET has already been set */
4474 synprot_error(L_smtp_syntax_error, 501, NULL,
4475 US"RET can be specified once only");
4478 dsn_ret = strcmpic(value, US"HDRS") == 0
4480 : strcmpic(value, US"FULL") == 0
4483 DEBUG(D_receive) debug_printf("DSN_RET: %d\n", dsn_ret);
4484 /* Check for invalid invalid value, and exit with error */
4487 synprot_error(L_smtp_syntax_error, 501, NULL,
4488 US"Value for RET is invalid");
4493 case ENV_MAIL_OPT_ENVID:
4496 /* Check if the dsn envid has been already set */
4497 if (dsn_envid != NULL)
4499 synprot_error(L_smtp_syntax_error, 501, NULL,
4500 US"ENVID can be specified once only");
4503 dsn_envid = string_copy(value);
4504 DEBUG(D_receive) debug_printf("DSN_ENVID: %s\n", dsn_envid);
4508 /* Handle the AUTH extension. If the value given is not "<>" and either
4509 the ACL says "yes" or there is no ACL but the sending host is
4510 authenticated, we set it up as the authenticated sender. However, if the
4511 authenticator set a condition to be tested, we ignore AUTH on MAIL unless
4512 the condition is met. The value of AUTH is an xtext, which means that +,
4513 = and cntrl chars are coded in hex; however "<>" is unaffected by this
4515 case ENV_MAIL_OPT_AUTH:
4516 if (Ustrcmp(value, "<>") != 0)
4521 if (auth_xtextdecode(value, &authenticated_sender) < 0)
4523 /* Put back terminator overrides for error message */
4526 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4527 US"invalid data for AUTH");
4530 if (acl_smtp_mailauth == NULL)
4532 ignore_msg = US"client not authenticated";
4533 rc = (sender_host_authenticated != NULL)? OK : FAIL;
4537 ignore_msg = US"rejected by ACL";
4538 rc = acl_check(ACL_WHERE_MAILAUTH, NULL, acl_smtp_mailauth,
4539 &user_msg, &log_msg);
4545 if (authenticated_by == NULL ||
4546 authenticated_by->mail_auth_condition == NULL ||
4547 expand_check_condition(authenticated_by->mail_auth_condition,
4548 authenticated_by->name, US"authenticator"))
4549 break; /* Accept the AUTH */
4551 ignore_msg = US"server_mail_auth_condition failed";
4552 if (authenticated_id != NULL)
4553 ignore_msg = string_sprintf("%s: authenticated ID=\"%s\"",
4554 ignore_msg, authenticated_id);
4559 authenticated_sender = NULL;
4560 log_write(0, LOG_MAIN, "ignoring AUTH=%s from %s (%s)",
4561 value, host_and_ident(TRUE), ignore_msg);
4564 /* Should only get DEFER or ERROR here. Put back terminator
4565 overrides for error message */
4570 (void)smtp_handle_acl_fail(ACL_WHERE_MAILAUTH, rc, user_msg,
4577 #ifndef DISABLE_PRDR
4578 case ENV_MAIL_OPT_PRDR:
4580 prdr_requested = TRUE;
4585 case ENV_MAIL_OPT_UTF8:
4586 if (smtputf8_advertised)
4588 int old_pool = store_pool;
4590 DEBUG(D_receive) debug_printf("smtputf8 requested\n");
4591 message_smtputf8 = allow_utf8_domains = TRUE;
4592 store_pool = POOL_PERM;
4593 received_protocol = string_sprintf("utf8%s", received_protocol);
4594 store_pool = old_pool;
4598 /* No valid option. Stick back the terminator characters and break
4599 the loop. Do the name-terminator second as extract_option sets
4600 value==name when it found no equal-sign.
4601 An error for a malformed address will occur. */
4602 case ENV_MAIL_OPT_NULL:
4610 /* Break out of for loop if switch() had bad argument or
4611 when start of the email address is reached */
4612 if (arg_error) break;
4615 /* If we have passed the threshold for rate limiting, apply the current
4616 delay, and update it for next time, provided this is a limited host. */
4618 if (smtp_mailcmd_count > smtp_rlm_threshold &&
4619 verify_check_host(&smtp_ratelimit_hosts) == OK)
4621 DEBUG(D_receive) debug_printf("rate limit MAIL: delay %.3g sec\n",
4622 smtp_delay_mail/1000.0);
4623 millisleep((int)smtp_delay_mail);
4624 smtp_delay_mail *= smtp_rlm_factor;
4625 if (smtp_delay_mail > (double)smtp_rlm_limit)
4626 smtp_delay_mail = (double)smtp_rlm_limit;
4629 /* Now extract the address, first applying any SMTP-time rewriting. The
4630 TRUE flag allows "<>" as a sender address. */
4632 raw_sender = rewrite_existflags & rewrite_smtp
4633 ? rewrite_one(smtp_cmd_data, rewrite_smtp, NULL, FALSE, US"",
4634 global_rewrite_rules)
4638 parse_extract_address(raw_sender, &errmess, &start, &end, &sender_domain,
4643 done = synprot_error(L_smtp_syntax_error, 501, smtp_cmd_data, errmess);
4647 sender_address = raw_sender;
4649 /* If there is a configured size limit for mail, check that this message
4650 doesn't exceed it. The check is postponed to this point so that the sender
4653 if (thismessage_size_limit > 0 && message_size > thismessage_size_limit)
4655 smtp_printf("552 Message size exceeds maximum permitted\r\n", FALSE);
4656 log_write(L_size_reject,
4657 LOG_MAIN|LOG_REJECT, "rejected MAIL FROM:<%s> %s: "
4658 "message too big: size%s=%d max=%d",
4660 host_and_ident(TRUE),
4661 (message_size == INT_MAX)? ">" : "",
4663 thismessage_size_limit);
4664 sender_address = NULL;
4668 /* Check there is enough space on the disk unless configured not to.
4669 When smtp_check_spool_space is set, the check is for thismessage_size_limit
4670 plus the current message - i.e. we accept the message only if it won't
4671 reduce the space below the threshold. Add 5000 to the size to allow for
4672 overheads such as the Received: line and storing of recipients, etc.
4673 By putting the check here, even when SIZE is not given, it allow VRFY
4674 and EXPN etc. to be used when space is short. */
4676 if (!receive_check_fs(
4677 (smtp_check_spool_space && message_size >= 0)?
4678 message_size + 5000 : 0))
4680 smtp_printf("452 Space shortage, please try later\r\n", FALSE);
4681 sender_address = NULL;
4685 /* If sender_address is unqualified, reject it, unless this is a locally
4686 generated message, or the sending host or net is permitted to send
4687 unqualified addresses - typically local machines behaving as MUAs -
4688 in which case just qualify the address. The flag is set above at the start
4689 of the SMTP connection. */
4691 if (sender_domain == 0 && sender_address[0] != 0)
4693 if (allow_unqualified_sender)
4695 sender_domain = Ustrlen(sender_address) + 1;
4696 sender_address = rewrite_address_qualify(sender_address, FALSE);
4697 DEBUG(D_receive) debug_printf("unqualified address %s accepted\n",
4702 smtp_printf("501 %s: sender address must contain a domain\r\n", FALSE,
4704 log_write(L_smtp_syntax_error,
4705 LOG_MAIN|LOG_REJECT,
4706 "unqualified sender rejected: <%s> %s%s",
4708 host_and_ident(TRUE),
4710 sender_address = NULL;
4715 /* Apply an ACL check if one is defined, before responding. Afterwards,
4716 when pipelining is not advertised, do another sync check in case the ACL
4717 delayed and the client started sending in the meantime. */
4721 rc = acl_check(ACL_WHERE_MAIL, NULL, acl_smtp_mail, &user_msg, &log_msg);
4722 if (rc == OK && !pipelining_advertised && !check_sync())
4728 if (rc == OK || rc == DISCARD)
4730 BOOL more = pipeline_response();
4733 smtp_printf("%s%s%s", more, US"250 OK",
4734 #ifndef DISABLE_PRDR
4735 prdr_requested ? US", PRDR Requested" : US"",
4742 #ifndef DISABLE_PRDR
4744 user_msg = string_sprintf("%s%s", user_msg, US", PRDR Requested");
4746 smtp_user_msg(US"250", user_msg);
4748 smtp_delay_rcpt = smtp_rlr_base;
4749 recipients_discarded = (rc == DISCARD);
4750 was_rej_mail = FALSE;
4754 done = smtp_handle_acl_fail(ACL_WHERE_MAIL, rc, user_msg, log_msg);
4755 sender_address = NULL;
4760 /* The RCPT command requires an address as an operand. There may be any
4761 number of RCPT commands, specifying multiple recipients. We build them all
4762 into a data structure. The start/end values given by parse_extract_address
4763 are not used, as we keep only the extracted address. */
4768 was_rcpt = rcpt_in_progress = TRUE;
4770 /* There must be a sender address; if the sender was rejected and
4771 pipelining was advertised, we assume the client was pipelining, and do not
4772 count this as a protocol error. Reset was_rej_mail so that further RCPTs
4773 get the same treatment. */
4775 if (sender_address == NULL)
4777 if (pipelining_advertised && last_was_rej_mail)
4779 smtp_printf("503 sender not yet given\r\n", FALSE);
4780 was_rej_mail = TRUE;
4784 done = synprot_error(L_smtp_protocol_error, 503, NULL,
4785 US"sender not yet given");
4786 was_rcpt = FALSE; /* Not a valid RCPT */
4792 /* Check for an operand */
4794 if (smtp_cmd_data[0] == 0)
4796 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4797 US"RCPT must have an address operand");
4802 /* Set the DSN flags orcpt and dsn_flags from the session*/
4808 uschar *name, *value;
4810 if (!extract_option(&name, &value))
4813 if (dsn_advertised && strcmpic(name, US"ORCPT") == 0)
4815 /* Check whether orcpt has been already set */
4818 synprot_error(L_smtp_syntax_error, 501, NULL,
4819 US"ORCPT can be specified once only");
4822 orcpt = string_copy(value);
4823 DEBUG(D_receive) debug_printf("DSN orcpt: %s\n", orcpt);
4826 else if (dsn_advertised && strcmpic(name, US"NOTIFY") == 0)
4828 /* Check if the notify flags have been already set */
4831 synprot_error(L_smtp_syntax_error, 501, NULL,
4832 US"NOTIFY can be specified once only");
4835 if (strcmpic(value, US"NEVER") == 0)
4836 flags |= rf_notify_never;
4843 while (*pp != 0 && *pp != ',') pp++;
4844 if (*pp == ',') *pp++ = 0;
4845 if (strcmpic(p, US"SUCCESS") == 0)
4847 DEBUG(D_receive) debug_printf("DSN: Setting notify success\n");
4848 flags |= rf_notify_success;
4850 else if (strcmpic(p, US"FAILURE") == 0)
4852 DEBUG(D_receive) debug_printf("DSN: Setting notify failure\n");
4853 flags |= rf_notify_failure;
4855 else if (strcmpic(p, US"DELAY") == 0)
4857 DEBUG(D_receive) debug_printf("DSN: Setting notify delay\n");
4858 flags |= rf_notify_delay;
4862 /* Catch any strange values */
4863 synprot_error(L_smtp_syntax_error, 501, NULL,
4864 US"Invalid value for NOTIFY parameter");
4869 DEBUG(D_receive) debug_printf("DSN Flags: %x\n", flags);
4873 /* Unknown option. Stick back the terminator characters and break
4874 the loop. An error for a malformed address will occur. */
4878 DEBUG(D_receive) debug_printf("Invalid RCPT option: %s : %s\n", name, value);
4885 /* Apply SMTP rewriting then extract the working address. Don't allow "<>"
4886 as a recipient address */
4888 recipient = rewrite_existflags & rewrite_smtp
4889 ? rewrite_one(smtp_cmd_data, rewrite_smtp, NULL, FALSE, US"",
4890 global_rewrite_rules)
4893 if (!(recipient = parse_extract_address(recipient, &errmess, &start, &end,
4894 &recipient_domain, FALSE)))
4896 done = synprot_error(L_smtp_syntax_error, 501, smtp_cmd_data, errmess);
4901 /* If the recipient address is unqualified, reject it, unless this is a
4902 locally generated message. However, unqualified addresses are permitted
4903 from a configured list of hosts and nets - typically when behaving as
4904 MUAs rather than MTAs. Sad that SMTP is used for both types of traffic,
4905 really. The flag is set at the start of the SMTP connection.
4907 RFC 1123 talks about supporting "the reserved mailbox postmaster"; I always
4908 assumed this meant "reserved local part", but the revision of RFC 821 and
4909 friends now makes it absolutely clear that it means *mailbox*. Consequently
4910 we must always qualify this address, regardless. */
4912 if (!recipient_domain)
4913 if (!(recipient_domain = qualify_recipient(&recipient, smtp_cmd_data,
4920 /* Check maximum allowed */
4922 if (rcpt_count > recipients_max && recipients_max > 0)
4924 if (recipients_max_reject)
4927 smtp_printf("552 too many recipients\r\n", FALSE);
4929 log_write(0, LOG_MAIN|LOG_REJECT, "too many recipients: message "
4930 "rejected: sender=<%s> %s", sender_address, host_and_ident(TRUE));
4935 smtp_printf("452 too many recipients\r\n", FALSE);
4937 log_write(0, LOG_MAIN|LOG_REJECT, "too many recipients: excess "
4938 "temporarily rejected: sender=<%s> %s", sender_address,
4939 host_and_ident(TRUE));
4946 /* If we have passed the threshold for rate limiting, apply the current
4947 delay, and update it for next time, provided this is a limited host. */
4949 if (rcpt_count > smtp_rlr_threshold &&
4950 verify_check_host(&smtp_ratelimit_hosts) == OK)
4952 DEBUG(D_receive) debug_printf("rate limit RCPT: delay %.3g sec\n",
4953 smtp_delay_rcpt/1000.0);
4954 millisleep((int)smtp_delay_rcpt);
4955 smtp_delay_rcpt *= smtp_rlr_factor;
4956 if (smtp_delay_rcpt > (double)smtp_rlr_limit)
4957 smtp_delay_rcpt = (double)smtp_rlr_limit;
4960 /* If the MAIL ACL discarded all the recipients, we bypass ACL checking
4961 for them. Otherwise, check the access control list for this recipient. As
4962 there may be a delay in this, re-check for a synchronization error
4963 afterwards, unless pipelining was advertised. */
4965 if (recipients_discarded)
4968 if ( (rc = acl_check(ACL_WHERE_RCPT, recipient, acl_smtp_rcpt, &user_msg,
4970 && !pipelining_advertised && !check_sync())
4973 /* The ACL was happy */
4977 BOOL more = pipeline_response();
4980 smtp_user_msg(US"250", user_msg);
4982 smtp_printf("250 Accepted\r\n", more);
4983 receive_add_recipient(recipient, -1);
4985 /* Set the dsn flags in the recipients_list */
4986 recipients_list[recipients_count-1].orcpt = orcpt;
4987 recipients_list[recipients_count-1].dsn_flags = flags;
4989 DEBUG(D_receive) debug_printf("DSN: orcpt: %s flags: %d\n",
4990 recipients_list[recipients_count-1].orcpt,
4991 recipients_list[recipients_count-1].dsn_flags);
4994 /* The recipient was discarded */
4996 else if (rc == DISCARD)
4999 smtp_user_msg(US"250", user_msg);
5001 smtp_printf("250 Accepted\r\n", FALSE);
5004 log_write(0, LOG_MAIN|LOG_REJECT, "%s F=<%s> RCPT %s: "
5005 "discarded by %s ACL%s%s", host_and_ident(TRUE),
5006 sender_address_unrewritten? sender_address_unrewritten : sender_address,
5007 smtp_cmd_argument, recipients_discarded? "MAIL" : "RCPT",
5008 log_msg ? US": " : US"", log_msg ? log_msg : US"");
5011 /* Either the ACL failed the address, or it was deferred. */
5015 if (rc == FAIL) rcpt_fail_count++; else rcpt_defer_count++;
5016 done = smtp_handle_acl_fail(ACL_WHERE_RCPT, rc, user_msg, log_msg);
5021 /* The DATA command is legal only if it follows successful MAIL FROM
5022 and RCPT TO commands. However, if pipelining is advertised, a bad DATA is
5023 not counted as a protocol error if it follows RCPT (which must have been
5024 rejected if there are no recipients.) This function is complete when a
5025 valid DATA command is encountered.
5027 Note concerning the code used: RFC 2821 says this:
5029 - If there was no MAIL, or no RCPT, command, or all such commands
5030 were rejected, the server MAY return a "command out of sequence"
5031 (503) or "no valid recipients" (554) reply in response to the
5034 The example in the pipelining RFC 2920 uses 554, but I use 503 here
5035 because it is the same whether pipelining is in use or not.
5037 If all the RCPT commands that precede DATA provoked the same error message
5038 (often indicating some kind of system error), it is helpful to include it
5039 with the DATA rejection (an idea suggested by Tony Finch). */
5046 if (chunking_state != CHUNKING_OFFERED)
5048 done = synprot_error(L_smtp_protocol_error, 503, NULL,
5049 US"BDAT command used when CHUNKING not advertised");
5053 /* grab size, endmarker */
5055 if (sscanf(CS smtp_cmd_data, "%u %n", &chunking_datasize, &n) < 1)
5057 done = synprot_error(L_smtp_protocol_error, 501, NULL,
5058 US"missing size for BDAT command");
5061 chunking_state = strcmpic(smtp_cmd_data+n, US"LAST") == 0
5062 ? CHUNKING_LAST : CHUNKING_ACTIVE;
5063 chunking_data_left = chunking_datasize;
5064 DEBUG(D_receive) debug_printf("chunking state %d, %d bytes\n",
5065 (int)chunking_state, chunking_data_left);
5067 lwr_receive_getc = receive_getc;
5068 lwr_receive_getbuf = receive_getbuf;
5069 lwr_receive_ungetc = receive_ungetc;
5070 receive_getc = bdat_getc;
5071 receive_ungetc = bdat_ungetc;
5079 DATA_BDAT: /* Common code for DATA and BDAT */
5080 if (!discarded && recipients_count <= 0)
5082 if (rcpt_smtp_response_same && rcpt_smtp_response != NULL)
5084 uschar *code = US"503";
5085 int len = Ustrlen(rcpt_smtp_response);
5086 smtp_respond(code, 3, FALSE, US"All RCPT commands were rejected with "
5088 /* Responses from smtp_printf() will have \r\n on the end */
5089 if (len > 2 && rcpt_smtp_response[len-2] == '\r')
5090 rcpt_smtp_response[len-2] = 0;
5091 smtp_respond(code, 3, FALSE, rcpt_smtp_response);
5093 if (pipelining_advertised && last_was_rcpt)
5094 smtp_printf("503 Valid RCPT command must precede %s\r\n", FALSE,
5095 smtp_names[smtp_connection_had[smtp_ch_index-1]]);
5097 done = synprot_error(L_smtp_protocol_error, 503, NULL,
5098 smtp_connection_had[smtp_ch_index-1] == SCH_DATA
5099 ? US"valid RCPT command must precede DATA"
5100 : US"valid RCPT command must precede BDAT");
5102 if (chunking_state > CHUNKING_OFFERED)
5107 if (toomany && recipients_max_reject)
5109 sender_address = NULL; /* This will allow a new MAIL without RSET */
5110 sender_address_unrewritten = NULL;
5111 smtp_printf("554 Too many recipients\r\n", FALSE);
5115 if (chunking_state > CHUNKING_OFFERED)
5116 rc = OK; /* No predata ACL or go-ahead output for BDAT */
5119 /* If there is an ACL, re-check the synchronization afterwards, since the
5120 ACL may have delayed. To handle cutthrough delivery enforce a dummy call
5121 to get the DATA command sent. */
5123 if (acl_smtp_predata == NULL && cutthrough.fd < 0)
5127 uschar * acl = acl_smtp_predata ? acl_smtp_predata : US"accept";
5128 enable_dollar_recipients = TRUE;
5129 rc = acl_check(ACL_WHERE_PREDATA, NULL, acl, &user_msg,
5131 enable_dollar_recipients = FALSE;
5132 if (rc == OK && !check_sync())
5136 { /* Either the ACL failed the address, or it was deferred. */
5137 done = smtp_handle_acl_fail(ACL_WHERE_PREDATA, rc, user_msg, log_msg);
5143 smtp_user_msg(US"354", user_msg);
5146 "354 Enter message, ending with \".\" on a line by itself\r\n", FALSE);
5150 if (smtp_in) /* all ACKs needed to ramp window up for bulk data */
5151 (void) setsockopt(fileno(smtp_in), IPPROTO_TCP, TCP_QUICKACK,
5152 US &on, sizeof(on));
5155 message_ended = END_NOTENDED; /* Indicate in middle of data */
5166 if (!(address = parse_extract_address(smtp_cmd_data, &errmess,
5167 &start, &end, &recipient_domain, FALSE)))
5169 smtp_printf("501 %s\r\n", FALSE, errmess);
5173 if (!recipient_domain)
5174 if (!(recipient_domain = qualify_recipient(&address, smtp_cmd_data,
5178 if ((rc = acl_check(ACL_WHERE_VRFY, address, acl_smtp_vrfy,
5179 &user_msg, &log_msg)) != OK)
5180 done = smtp_handle_acl_fail(ACL_WHERE_VRFY, rc, user_msg, log_msg);
5184 address_item * addr = deliver_make_addr(address, FALSE);
5186 switch(verify_address(addr, NULL, vopt_is_recipient | vopt_qualify, -1,
5187 -1, -1, NULL, NULL, NULL))
5190 s = string_sprintf("250 <%s> is deliverable", address);
5194 s = (addr->user_message != NULL)?
5195 string_sprintf("451 <%s> %s", address, addr->user_message) :
5196 string_sprintf("451 Cannot resolve <%s> at this time", address);
5200 s = (addr->user_message != NULL)?
5201 string_sprintf("550 <%s> %s", address, addr->user_message) :
5202 string_sprintf("550 <%s> is not deliverable", address);
5203 log_write(0, LOG_MAIN, "VRFY failed for %s %s",
5204 smtp_cmd_argument, host_and_ident(TRUE));
5208 smtp_printf("%s\r\n", FALSE, s);
5216 rc = acl_check(ACL_WHERE_EXPN, NULL, acl_smtp_expn, &user_msg, &log_msg);
5218 done = smtp_handle_acl_fail(ACL_WHERE_EXPN, rc, user_msg, log_msg);
5221 BOOL save_log_testing_mode = log_testing_mode;
5222 address_test_mode = log_testing_mode = TRUE;
5223 (void) verify_address(deliver_make_addr(smtp_cmd_data, FALSE),
5224 smtp_out, vopt_is_recipient | vopt_qualify | vopt_expn, -1, -1, -1,
5226 address_test_mode = FALSE;
5227 log_testing_mode = save_log_testing_mode; /* true for -bh */
5236 if (!tls_advertised)
5238 done = synprot_error(L_smtp_protocol_error, 503, NULL,
5239 US"STARTTLS command used when not advertised");
5243 /* Apply an ACL check if one is defined */
5245 if ( acl_smtp_starttls
5246 && (rc = acl_check(ACL_WHERE_STARTTLS, NULL, acl_smtp_starttls,
5247 &user_msg, &log_msg)) != OK
5250 done = smtp_handle_acl_fail(ACL_WHERE_STARTTLS, rc, user_msg, log_msg);
5254 /* RFC 2487 is not clear on when this command may be sent, though it
5255 does state that all information previously obtained from the client
5256 must be discarded if a TLS session is started. It seems reasonable to
5257 do an implied RSET when STARTTLS is received. */
5259 incomplete_transaction_log(US"STARTTLS");
5260 cancel_cutthrough_connection(TRUE, US"STARTTLS received");
5261 smtp_reset(reset_point);
5263 cmd_list[CMD_LIST_STARTTLS].is_mail_cmd = FALSE;
5265 /* There's an attack where more data is read in past the STARTTLS command
5266 before TLS is negotiated, then assumed to be part of the secure session
5267 when used afterwards; we use segregated input buffers, so are not
5268 vulnerable, but we want to note when it happens and, for sheer paranoia,
5269 ensure that the buffer is "wiped".
5270 Pipelining sync checks will normally have protected us too, unless disabled
5271 by configuration. */
5273 if (receive_smtp_buffered())
5276 debug_printf("Non-empty input buffer after STARTTLS; naive attack?\n");
5277 if (tls_in.active < 0)
5278 smtp_inend = smtp_inptr = smtp_inbuffer;
5279 /* and if TLS is already active, tls_server_start() should fail */
5282 /* There is nothing we value in the input buffer and if TLS is successfully
5283 negotiated, we won't use this buffer again; if TLS fails, we'll just read
5284 fresh content into it. The buffer contains arbitrary content from an
5285 untrusted remote source; eg: NOOP <shellcode>\r\nSTARTTLS\r\n
5286 It seems safest to just wipe away the content rather than leave it as a
5287 target to jump to. */
5289 memset(smtp_inbuffer, 0, IN_BUFFER_SIZE);
5291 /* Attempt to start up a TLS session, and if successful, discard all
5292 knowledge that was obtained previously. At least, that's what the RFC says,
5293 and that's what happens by default. However, in order to work round YAEB,
5294 there is an option to remember the esmtp state. Sigh.
5296 We must allow for an extra EHLO command and an extra AUTH command after
5297 STARTTLS that don't add to the nonmail command count. */
5300 if ((rc = tls_server_start(tls_require_ciphers, &s)) == OK)
5302 if (!tls_remember_esmtp)
5303 helo_seen = esmtp = auth_advertised = pipelining_advertised = FALSE;
5304 cmd_list[CMD_LIST_EHLO].is_mail_cmd = TRUE;
5305 cmd_list[CMD_LIST_AUTH].is_mail_cmd = TRUE;
5306 cmd_list[CMD_LIST_TLS_AUTH].is_mail_cmd = TRUE;
5307 if (sender_helo_name != NULL)
5309 store_free(sender_helo_name);
5310 sender_helo_name = NULL;
5311 host_build_sender_fullhost(); /* Rebuild */
5312 set_process_info("handling incoming TLS connection from %s",
5313 host_and_ident(FALSE));
5316 (sender_host_address ? protocols : protocols_local)
5318 ? pextend + (sender_host_authenticated ? pauthed : 0)
5320 + (tls_in.active >= 0 ? pcrpted : 0)
5323 sender_host_authenticated = NULL;
5324 authenticated_id = NULL;
5325 sync_cmd_limit = NON_SYNC_CMD_NON_PIPELINING;
5326 DEBUG(D_tls) debug_printf("TLS active\n");
5327 break; /* Successful STARTTLS */
5330 (void) smtp_log_tls_fail(s);
5332 /* Some local configuration problem was discovered before actually trying
5333 to do a TLS handshake; give a temporary error. */
5337 smtp_printf("454 TLS currently unavailable\r\n", FALSE);
5341 /* Hard failure. Reject everything except QUIT or closed connection. One
5342 cause for failure is a nested STARTTLS, in which case tls_in.active remains
5343 set, but we must still reject all incoming commands. */
5345 DEBUG(D_tls) debug_printf("TLS failed to start\n");
5346 while (done <= 0) switch(smtp_read_command(FALSE, GETC_BUFFER_UNLIMITED))
5349 log_write(L_smtp_connection, LOG_MAIN, "%s closed by EOF",
5350 smtp_get_connection_info());
5351 smtp_notquit_exit(US"tls-failed", NULL, NULL);
5355 /* It is perhaps arguable as to which exit ACL should be called here,
5356 but as it is probably a situation that almost never arises, it
5357 probably doesn't matter. We choose to call the real QUIT ACL, which in
5358 some sense is perhaps "right". */
5363 && ((rc = acl_check(ACL_WHERE_QUIT, NULL, acl_smtp_quit, &user_msg,
5364 &log_msg)) == ERROR))
5365 log_write(0, LOG_MAIN|LOG_PANIC, "ACL for QUIT returned ERROR: %s",
5368 smtp_respond(US"221", 3, TRUE, user_msg);
5370 smtp_printf("221 %s closing connection\r\n", FALSE, smtp_active_hostname);
5371 log_write(L_smtp_connection, LOG_MAIN, "%s closed by QUIT",
5372 smtp_get_connection_info());
5377 smtp_printf("554 Security failure\r\n", FALSE);
5380 tls_close(TRUE, TRUE);
5385 /* The ACL for QUIT is provided for gathering statistical information or
5386 similar; it does not affect the response code, but it can supply a custom
5390 smtp_quit_handler(&user_msg, &log_msg);
5396 smtp_rset_handler();
5397 cancel_cutthrough_connection(TRUE, US"RSET received");
5398 smtp_reset(reset_point);
5405 smtp_printf("250 OK\r\n", FALSE);
5409 /* Show ETRN/EXPN/VRFY if there's an ACL for checking hosts; if actually
5410 used, a check will be done for permitted hosts. Show STARTTLS only if not
5411 already in a TLS session and if it would be advertised in the EHLO
5416 smtp_printf("214-Commands supported:\r\n", TRUE);
5420 Ustrcat(buffer, " AUTH");
5422 if (tls_in.active < 0 &&
5423 verify_check_host(&tls_advertise_hosts) != FAIL)
5424 Ustrcat(buffer, " STARTTLS");
5426 Ustrcat(buffer, " HELO EHLO MAIL RCPT DATA BDAT");
5427 Ustrcat(buffer, " NOOP QUIT RSET HELP");
5428 if (acl_smtp_etrn != NULL) Ustrcat(buffer, " ETRN");
5429 if (acl_smtp_expn != NULL) Ustrcat(buffer, " EXPN");
5430 if (acl_smtp_vrfy != NULL) Ustrcat(buffer, " VRFY");
5431 smtp_printf("214%s\r\n", FALSE, buffer);
5437 incomplete_transaction_log(US"connection lost");
5438 smtp_notquit_exit(US"connection-lost", US"421",
5439 US"%s lost input connection", smtp_active_hostname);
5441 /* Don't log by default unless in the middle of a message, as some mailers
5442 just drop the call rather than sending QUIT, and it clutters up the logs.
5445 if (sender_address != NULL || recipients_count > 0)
5446 log_write(L_lost_incoming_connection,
5448 "unexpected %s while reading SMTP command from %s%s",
5449 sender_host_unknown? "EOF" : "disconnection",
5450 host_and_ident(FALSE), smtp_read_error);
5452 else log_write(L_smtp_connection, LOG_MAIN, "%s lost%s",
5453 smtp_get_connection_info(), smtp_read_error);
5461 if (sender_address != NULL)
5463 done = synprot_error(L_smtp_protocol_error, 503, NULL,
5464 US"ETRN is not permitted inside a transaction");
5468 log_write(L_etrn, LOG_MAIN, "ETRN %s received from %s", smtp_cmd_argument,
5469 host_and_ident(FALSE));
5471 if ((rc = acl_check(ACL_WHERE_ETRN, NULL, acl_smtp_etrn,
5472 &user_msg, &log_msg)) != OK)
5474 done = smtp_handle_acl_fail(ACL_WHERE_ETRN, rc, user_msg, log_msg);
5478 /* Compute the serialization key for this command. */
5480 etrn_serialize_key = string_sprintf("etrn-%s\n", smtp_cmd_data);
5482 /* If a command has been specified for running as a result of ETRN, we
5483 permit any argument to ETRN. If not, only the # standard form is permitted,
5484 since that is strictly the only kind of ETRN that can be implemented
5485 according to the RFC. */
5487 if (smtp_etrn_command != NULL)
5491 etrn_command = smtp_etrn_command;
5492 deliver_domain = smtp_cmd_data;
5493 rc = transport_set_up_command(&argv, smtp_etrn_command, TRUE, 0, NULL,
5494 US"ETRN processing", &error);
5495 deliver_domain = NULL;
5498 log_write(0, LOG_MAIN|LOG_PANIC, "failed to set up ETRN command: %s",
5500 smtp_printf("458 Internal failure\r\n", FALSE);
5505 /* Else set up to call Exim with the -R option. */
5509 if (*smtp_cmd_data++ != '#')
5511 done = synprot_error(L_smtp_syntax_error, 501, NULL,
5512 US"argument must begin with #");
5515 etrn_command = US"exim -R";
5516 argv = CUSS child_exec_exim(CEE_RETURN_ARGV, TRUE, NULL, TRUE,
5517 *queue_name ? 4 : 2,
5518 US"-R", smtp_cmd_data,
5519 US"-MCG", queue_name);
5522 /* If we are host-testing, don't actually do anything. */
5528 debug_printf("ETRN command is: %s\n", etrn_command);
5529 debug_printf("ETRN command execution skipped\n");
5531 if (user_msg == NULL) smtp_printf("250 OK\r\n", FALSE);
5532 else smtp_user_msg(US"250", user_msg);
5537 /* If ETRN queue runs are to be serialized, check the database to
5538 ensure one isn't already running. */
5540 if (smtp_etrn_serialize && !enq_start(etrn_serialize_key, 1))
5542 smtp_printf("458 Already processing %s\r\n", FALSE, smtp_cmd_data);
5546 /* Fork a child process and run the command. We don't want to have to
5547 wait for the process at any point, so set SIGCHLD to SIG_IGN before
5548 forking. It should be set that way anyway for external incoming SMTP,
5549 but we save and restore to be tidy. If serialization is required, we
5550 actually run the command in yet another process, so we can wait for it
5551 to complete and then remove the serialization lock. */
5553 oldsignal = signal(SIGCHLD, SIG_IGN);
5555 if ((pid = fork()) == 0)
5557 smtp_input = FALSE; /* This process is not associated with the */
5558 (void)fclose(smtp_in); /* SMTP call any more. */
5559 (void)fclose(smtp_out);
5561 signal(SIGCHLD, SIG_DFL); /* Want to catch child */
5563 /* If not serializing, do the exec right away. Otherwise, fork down
5564 into another process. */
5566 if (!smtp_etrn_serialize || (pid = fork()) == 0)
5568 DEBUG(D_exec) debug_print_argv(argv);
5569 exim_nullstd(); /* Ensure std{in,out,err} exist */
5570 execv(CS argv[0], (char *const *)argv);
5571 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "exec of \"%s\" (ETRN) failed: %s",
5572 etrn_command, strerror(errno));
5573 _exit(EXIT_FAILURE); /* paranoia */
5576 /* Obey this if smtp_serialize and the 2nd fork yielded non-zero. That
5577 is, we are in the first subprocess, after forking again. All we can do
5578 for a failing fork is to log it. Otherwise, wait for the 2nd process to
5579 complete, before removing the serialization. */
5582 log_write(0, LOG_MAIN|LOG_PANIC, "2nd fork for serialized ETRN "
5583 "failed: %s", strerror(errno));
5587 DEBUG(D_any) debug_printf("waiting for serialized ETRN process %d\n",
5589 (void)wait(&status);
5590 DEBUG(D_any) debug_printf("serialized ETRN process %d ended\n",
5594 enq_end(etrn_serialize_key);
5595 _exit(EXIT_SUCCESS);
5598 /* Back in the top level SMTP process. Check that we started a subprocess
5599 and restore the signal state. */
5603 log_write(0, LOG_MAIN|LOG_PANIC, "fork of process for ETRN failed: %s",
5605 smtp_printf("458 Unable to fork process\r\n", FALSE);
5606 if (smtp_etrn_serialize) enq_end(etrn_serialize_key);
5610 if (user_msg == NULL) smtp_printf("250 OK\r\n", FALSE);
5611 else smtp_user_msg(US"250", user_msg);
5614 signal(SIGCHLD, oldsignal);
5619 done = synprot_error(L_smtp_syntax_error, 501, NULL,
5620 US"unexpected argument data");
5624 /* This currently happens only for NULLs, but could be extended. */
5627 done = synprot_error(L_smtp_syntax_error, 0, NULL, /* Just logs */
5628 US"NULL character(s) present (shown as '?')");
5629 smtp_printf("501 NULL characters are not allowed in SMTP commands\r\n", FALSE);
5635 if (smtp_inend >= smtp_inbuffer + IN_BUFFER_SIZE)
5636 smtp_inend = smtp_inbuffer + IN_BUFFER_SIZE - 1;
5637 c = smtp_inend - smtp_inptr;
5638 if (c > 150) c = 150;
5640 incomplete_transaction_log(US"sync failure");
5641 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP protocol synchronization error "
5642 "(next input sent too soon: pipelining was%s advertised): "
5643 "rejected \"%s\" %s next input=\"%s\"",
5644 pipelining_advertised? "" : " not",
5645 smtp_cmd_buffer, host_and_ident(TRUE),
5646 string_printing(smtp_inptr));
5647 smtp_notquit_exit(US"synchronization-error", US"554",
5648 US"SMTP synchronization error");
5649 done = 1; /* Pretend eof - drops connection */
5653 case TOO_MANY_NONMAIL_CMD:
5654 s = smtp_cmd_buffer;
5655 while (*s != 0 && !isspace(*s)) s++;
5656 incomplete_transaction_log(US"too many non-mail commands");
5657 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
5658 "nonmail commands (last was \"%.*s\")", host_and_ident(FALSE),
5659 (int)(s - smtp_cmd_buffer), smtp_cmd_buffer);
5660 smtp_notquit_exit(US"bad-commands", US"554", US"Too many nonmail commands");
5661 done = 1; /* Pretend eof - drops connection */
5664 #ifdef SUPPORT_PROXY
5665 case PROXY_FAIL_IGNORE_CMD:
5666 smtp_printf("503 Command refused, required Proxy negotiation failed\r\n", FALSE);
5671 if (unknown_command_count++ >= smtp_max_unknown_commands)
5673 log_write(L_smtp_syntax_error, LOG_MAIN,
5674 "SMTP syntax error in \"%s\" %s %s",
5675 string_printing(smtp_cmd_buffer), host_and_ident(TRUE),
5676 US"unrecognized command");
5677 incomplete_transaction_log(US"unrecognized command");
5678 smtp_notquit_exit(US"bad-commands", US"500",
5679 US"Too many unrecognized commands");
5681 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
5682 "unrecognized commands (last was \"%s\")", host_and_ident(FALSE),
5683 string_printing(smtp_cmd_buffer));
5686 done = synprot_error(L_smtp_syntax_error, 500, NULL,
5687 US"unrecognized command");
5691 /* This label is used by goto's inside loops that want to break out to
5692 the end of the command-processing loop. */
5695 last_was_rej_mail = was_rej_mail; /* Remember some last commands for */
5696 last_was_rcpt = was_rcpt; /* protocol error handling */
5700 return done - 2; /* Convert yield values */
5705 /* End of smtp_in.c */