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)
343 return !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) 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), string_timesince(&smtp_connection_start), s);
1804 /* Return list of recent smtp commands */
1809 uschar * list = NULL;
1810 int size = 0, len = 0, i;
1812 for (i = smtp_ch_index; i < SMTP_HBUFF_SIZE; i++)
1813 if (smtp_connection_had[i] != SCH_NONE)
1814 list = string_append_listele(list, &size, &len, ',',
1815 smtp_names[smtp_connection_had[i]]);
1816 for (i = 0; i < smtp_ch_index; i++)
1817 list = string_append_listele(list, &size, &len, ',',
1818 smtp_names[smtp_connection_had[i]]);
1819 return list ? list : US"";
1825 /*************************************************
1826 * Check HELO line and set sender_helo_name *
1827 *************************************************/
1829 /* Check the format of a HELO line. The data for HELO/EHLO is supposed to be
1830 the domain name of the sending host, or an ip literal in square brackets. The
1831 argument is placed in sender_helo_name, which is in malloc store, because it
1832 must persist over multiple incoming messages. If helo_accept_junk is set, this
1833 host is permitted to send any old junk (needed for some broken hosts).
1834 Otherwise, helo_allow_chars can be used for rogue characters in general
1835 (typically people want to let in underscores).
1838 s the data portion of the line (already past any white space)
1840 Returns: TRUE or FALSE
1844 check_helo(uschar *s)
1847 uschar *end = s + Ustrlen(s);
1848 BOOL yield = helo_accept_junk;
1850 /* Discard any previous helo name */
1852 if (sender_helo_name != NULL)
1854 store_free(sender_helo_name);
1855 sender_helo_name = NULL;
1858 /* Skip tests if junk is permitted. */
1862 /* Allow the new standard form for IPv6 address literals, namely,
1863 [IPv6:....], and because someone is bound to use it, allow an equivalent
1864 IPv4 form. Allow plain addresses as well. */
1871 if (strncmpic(s, US"[IPv6:", 6) == 0)
1872 yield = (string_is_ip_address(s+6, NULL) == 6);
1873 else if (strncmpic(s, US"[IPv4:", 6) == 0)
1874 yield = (string_is_ip_address(s+6, NULL) == 4);
1876 yield = (string_is_ip_address(s+1, NULL) != 0);
1881 /* Non-literals must be alpha, dot, hyphen, plus any non-valid chars
1882 that have been configured (usually underscore - sigh). */
1889 if (!isalnum(*s) && *s != '.' && *s != '-' &&
1890 Ustrchr(helo_allow_chars, *s) == NULL)
1900 /* Save argument if OK */
1902 if (yield) sender_helo_name = string_copy_malloc(start);
1910 /*************************************************
1911 * Extract SMTP command option *
1912 *************************************************/
1914 /* This function picks the next option setting off the end of smtp_cmd_data. It
1915 is called for MAIL FROM and RCPT TO commands, to pick off the optional ESMTP
1916 things that can appear there.
1919 name point this at the name
1920 value point this at the data string
1922 Returns: TRUE if found an option
1926 extract_option(uschar **name, uschar **value)
1929 uschar *v = smtp_cmd_data + Ustrlen(smtp_cmd_data) - 1;
1930 while (isspace(*v)) v--;
1932 while (v > smtp_cmd_data && *v != '=' && !isspace(*v))
1934 /* Take care to not stop at a space embedded in a quoted local-part */
1936 if (*v == '"') do v--; while (*v != '"' && v > smtp_cmd_data+1);
1943 while(isalpha(n[-1])) n--;
1944 /* RFC says SP, but TAB seen in wild and other major MTAs accept it */
1945 if (!isspace(n[-1])) return FALSE;
1951 if (v == smtp_cmd_data) return FALSE;
1963 /*************************************************
1964 * Reset for new message *
1965 *************************************************/
1967 /* This function is called whenever the SMTP session is reset from
1968 within either of the setup functions.
1970 Argument: the stacking pool storage reset point
1975 smtp_reset(void *reset_point)
1977 recipients_list = NULL;
1978 rcpt_count = rcpt_defer_count = rcpt_fail_count =
1979 raw_recipients_count = recipients_count = recipients_list_max = 0;
1980 message_linecount = 0;
1982 acl_added_headers = NULL;
1983 acl_removed_headers = NULL;
1984 queue_only_policy = FALSE;
1985 rcpt_smtp_response = NULL;
1986 rcpt_smtp_response_same = TRUE;
1987 rcpt_in_progress = FALSE;
1988 deliver_freeze = FALSE; /* Can be set by ACL */
1989 freeze_tell = freeze_tell_config; /* Can be set by ACL */
1990 fake_response = OK; /* Can be set by ACL */
1991 #ifdef WITH_CONTENT_SCAN
1992 no_mbox_unspool = FALSE; /* Can be set by ACL */
1994 submission_mode = FALSE; /* Can be set by ACL */
1995 suppress_local_fixups = suppress_local_fixups_default; /* Can be set by ACL */
1996 active_local_from_check = local_from_check; /* Can be set by ACL */
1997 active_local_sender_retain = local_sender_retain; /* Can be set by ACL */
1998 sending_ip_address = NULL;
1999 return_path = sender_address = NULL;
2000 sender_data = NULL; /* Can be set by ACL */
2001 deliver_localpart_orig = NULL;
2002 deliver_domain_orig = NULL;
2003 callout_address = NULL;
2004 submission_name = NULL; /* Can be set by ACL */
2005 raw_sender = NULL; /* After SMTP rewrite, before qualifying */
2006 sender_address_unrewritten = NULL; /* Set only after verify rewrite */
2007 sender_verified_list = NULL; /* No senders verified */
2008 memset(sender_address_cache, 0, sizeof(sender_address_cache));
2009 memset(sender_domain_cache, 0, sizeof(sender_domain_cache));
2011 authenticated_sender = NULL;
2012 #ifdef EXPERIMENTAL_BRIGHTMAIL
2014 bmi_verdicts = NULL;
2016 dnslist_domain = dnslist_matched = NULL;
2017 #ifndef DISABLE_DKIM
2018 dkim_signers = NULL;
2019 dkim_disable_verify = FALSE;
2020 dkim_collect_input = FALSE;
2024 deliver_host = deliver_host_address = NULL; /* Can be set by ACL */
2025 #ifndef DISABLE_PRDR
2026 prdr_requested = FALSE;
2028 #ifdef EXPERIMENTAL_SPF
2029 spf_header_comment = NULL;
2030 spf_received = NULL;
2032 spf_smtp_comment = NULL;
2035 message_smtputf8 = FALSE;
2037 body_linecount = body_zerocount = 0;
2039 sender_rate = sender_rate_limit = sender_rate_period = NULL;
2040 ratelimiters_mail = NULL; /* Updated by ratelimit ACL condition */
2041 /* Note that ratelimiters_conn persists across resets. */
2043 /* Reset message ACL variables */
2047 /* The message body variables use malloc store. They may be set if this is
2048 not the first message in an SMTP session and the previous message caused them
2049 to be referenced in an ACL. */
2053 store_free(message_body);
2054 message_body = NULL;
2057 if (message_body_end)
2059 store_free(message_body_end);
2060 message_body_end = NULL;
2063 /* Warning log messages are also saved in malloc store. They are saved to avoid
2064 repetition in the same message, but it seems right to repeat them for different
2067 while (acl_warn_logged)
2069 string_item *this = acl_warn_logged;
2070 acl_warn_logged = acl_warn_logged->next;
2073 store_reset(reset_point);
2080 /*************************************************
2081 * Initialize for incoming batched SMTP message *
2082 *************************************************/
2084 /* This function is called from smtp_setup_msg() in the case when
2085 smtp_batched_input is true. This happens when -bS is used to pass a whole batch
2086 of messages in one file with SMTP commands between them. All errors must be
2087 reported by sending a message, and only MAIL FROM, RCPT TO, and DATA are
2088 relevant. After an error on a sender, or an invalid recipient, the remainder
2089 of the message is skipped. The value of received_protocol is already set.
2092 Returns: > 0 message successfully started (reached DATA)
2093 = 0 QUIT read or end of file reached
2094 < 0 should not occur
2098 smtp_setup_batch_msg(void)
2101 void *reset_point = store_get(0);
2103 /* Save the line count at the start of each transaction - single commands
2104 like HELO and RSET count as whole transactions. */
2106 bsmtp_transaction_linecount = receive_linecount;
2108 if ((receive_feof)()) return 0; /* Treat EOF as QUIT */
2110 cancel_cutthrough_connection(TRUE, US"smtp_setup_batch_msg");
2111 smtp_reset(reset_point); /* Reset for start of message */
2113 /* Deal with SMTP commands. This loop is exited by setting done to a POSITIVE
2114 value. The values are 2 larger than the required yield of the function. */
2119 uschar *recipient = NULL;
2120 int start, end, sender_domain, recipient_domain;
2122 switch(smtp_read_command(FALSE, GETC_BUFFER_UNLIMITED))
2124 /* The HELO/EHLO commands set sender_address_helo if they have
2125 valid data; otherwise they are ignored, except that they do
2126 a reset of the state. */
2131 check_helo(smtp_cmd_data);
2135 cancel_cutthrough_connection(TRUE, US"RSET received");
2136 smtp_reset(reset_point);
2137 bsmtp_transaction_linecount = receive_linecount;
2141 /* The MAIL FROM command requires an address as an operand. All we
2142 do here is to parse it for syntactic correctness. The form "<>" is
2143 a special case which converts into an empty string. The start/end
2144 pointers in the original are not used further for this address, as
2145 it is the canonical extracted address which is all that is kept. */
2148 smtp_mailcmd_count++; /* Count for no-mail log */
2149 if (sender_address != NULL)
2150 /* The function moan_smtp_batch() does not return. */
2151 moan_smtp_batch(smtp_cmd_buffer, "503 Sender already given");
2153 if (smtp_cmd_data[0] == 0)
2154 /* The function moan_smtp_batch() does not return. */
2155 moan_smtp_batch(smtp_cmd_buffer, "501 MAIL FROM must have an address operand");
2157 /* Reset to start of message */
2159 cancel_cutthrough_connection(TRUE, US"MAIL received");
2160 smtp_reset(reset_point);
2162 /* Apply SMTP rewrite */
2164 raw_sender = ((rewrite_existflags & rewrite_smtp) != 0)?
2165 rewrite_one(smtp_cmd_data, rewrite_smtp|rewrite_smtp_sender, NULL, FALSE,
2166 US"", global_rewrite_rules) : smtp_cmd_data;
2168 /* Extract the address; the TRUE flag allows <> as valid */
2171 parse_extract_address(raw_sender, &errmess, &start, &end, &sender_domain,
2174 if (raw_sender == NULL)
2175 /* The function moan_smtp_batch() does not return. */
2176 moan_smtp_batch(smtp_cmd_buffer, "501 %s", errmess);
2178 sender_address = string_copy(raw_sender);
2180 /* Qualify unqualified sender addresses if permitted to do so. */
2182 if (sender_domain == 0 && sender_address[0] != 0 && sender_address[0] != '@')
2184 if (allow_unqualified_sender)
2186 sender_address = rewrite_address_qualify(sender_address, FALSE);
2187 DEBUG(D_receive) debug_printf("unqualified address %s accepted "
2188 "and rewritten\n", raw_sender);
2190 /* The function moan_smtp_batch() does not return. */
2191 else moan_smtp_batch(smtp_cmd_buffer, "501 sender address must contain "
2197 /* The RCPT TO command requires an address as an operand. All we do
2198 here is to parse it for syntactic correctness. There may be any number
2199 of RCPT TO commands, specifying multiple senders. We build them all into
2200 a data structure that is in argc/argv format. The start/end values
2201 given by parse_extract_address are not used, as we keep only the
2202 extracted address. */
2205 if (sender_address == NULL)
2206 /* The function moan_smtp_batch() does not return. */
2207 moan_smtp_batch(smtp_cmd_buffer, "503 No sender yet given");
2209 if (smtp_cmd_data[0] == 0)
2210 /* The function moan_smtp_batch() does not return. */
2211 moan_smtp_batch(smtp_cmd_buffer, "501 RCPT TO must have an address operand");
2213 /* Check maximum number allowed */
2215 if (recipients_max > 0 && recipients_count + 1 > recipients_max)
2216 /* The function moan_smtp_batch() does not return. */
2217 moan_smtp_batch(smtp_cmd_buffer, "%s too many recipients",
2218 recipients_max_reject? "552": "452");
2220 /* Apply SMTP rewrite, then extract address. Don't allow "<>" as a
2221 recipient address */
2223 recipient = rewrite_existflags & rewrite_smtp
2224 ? rewrite_one(smtp_cmd_data, rewrite_smtp, NULL, FALSE, US"",
2225 global_rewrite_rules)
2228 recipient = parse_extract_address(recipient, &errmess, &start, &end,
2229 &recipient_domain, FALSE);
2232 /* The function moan_smtp_batch() does not return. */
2233 moan_smtp_batch(smtp_cmd_buffer, "501 %s", errmess);
2235 /* If the recipient address is unqualified, qualify it if permitted. Then
2236 add it to the list of recipients. */
2238 if (recipient_domain == 0)
2240 if (allow_unqualified_recipient)
2242 DEBUG(D_receive) debug_printf("unqualified address %s accepted\n",
2244 recipient = rewrite_address_qualify(recipient, TRUE);
2246 /* The function moan_smtp_batch() does not return. */
2247 else moan_smtp_batch(smtp_cmd_buffer, "501 recipient address must contain "
2250 receive_add_recipient(recipient, -1);
2254 /* The DATA command is legal only if it follows successful MAIL FROM
2255 and RCPT TO commands. This function is complete when a valid DATA
2256 command is encountered. */
2259 if (sender_address == NULL || recipients_count <= 0)
2261 /* The function moan_smtp_batch() does not return. */
2262 if (sender_address == NULL)
2263 moan_smtp_batch(smtp_cmd_buffer,
2264 "503 MAIL FROM:<sender> command must precede DATA");
2266 moan_smtp_batch(smtp_cmd_buffer,
2267 "503 RCPT TO:<recipient> must precede DATA");
2271 done = 3; /* DATA successfully achieved */
2272 message_ended = END_NOTENDED; /* Indicate in middle of message */
2277 /* The VRFY, EXPN, HELP, ETRN, and NOOP commands are ignored. */
2284 bsmtp_transaction_linecount = receive_linecount;
2295 /* The function moan_smtp_batch() does not return. */
2296 moan_smtp_batch(smtp_cmd_buffer, "501 Unexpected argument data");
2301 /* The function moan_smtp_batch() does not return. */
2302 moan_smtp_batch(smtp_cmd_buffer, "501 Unexpected NULL in SMTP command");
2307 /* The function moan_smtp_batch() does not return. */
2308 moan_smtp_batch(smtp_cmd_buffer, "500 Command unrecognized");
2313 return done - 2; /* Convert yield values */
2320 smtp_log_tls_fail(uschar * errstr)
2322 uschar * conn_info = smtp_get_connection_info();
2324 if (Ustrncmp(conn_info, US"SMTP ", 5) == 0) conn_info += 5;
2325 /* I'd like to get separated H= here, but too hard for now */
2327 log_write(0, LOG_MAIN, "TLS error on %s %s", conn_info, errstr);
2332 /*************************************************
2333 * Start an SMTP session *
2334 *************************************************/
2336 /* This function is called at the start of an SMTP session. Thereafter,
2337 smtp_setup_msg() is called to initiate each separate message. This
2338 function does host-specific testing, and outputs the banner line.
2341 Returns: FALSE if the session can not continue; something has
2342 gone wrong, or the connection to the host is blocked
2346 smtp_start_session(void)
2350 uschar *user_msg, *log_msg;
2354 gettimeofday(&smtp_connection_start, NULL);
2355 for (smtp_ch_index = 0; smtp_ch_index < SMTP_HBUFF_SIZE; smtp_ch_index++)
2356 smtp_connection_had[smtp_ch_index] = SCH_NONE;
2359 /* Default values for certain variables */
2361 helo_seen = esmtp = helo_accept_junk = FALSE;
2362 smtp_mailcmd_count = 0;
2363 count_nonmail = TRUE_UNSET;
2364 synprot_error_count = unknown_command_count = nonmail_command_count = 0;
2365 smtp_delay_mail = smtp_rlm_base;
2366 auth_advertised = FALSE;
2367 pipelining_advertised = FALSE;
2368 pipelining_enable = TRUE;
2369 sync_cmd_limit = NON_SYNC_CMD_NON_PIPELINING;
2370 smtp_exit_function_called = FALSE; /* For avoiding loop in not-quit exit */
2372 /* If receiving by -bs from a trusted user, or testing with -bh, we allow
2373 authentication settings from -oMaa to remain in force. */
2375 if (!host_checking && !sender_host_notsocket) sender_host_authenticated = NULL;
2376 authenticated_by = NULL;
2379 tls_in.cipher = tls_in.peerdn = NULL;
2380 tls_in.ourcert = tls_in.peercert = NULL;
2382 tls_in.ocsp = OCSP_NOT_REQ;
2383 tls_advertised = FALSE;
2385 dsn_advertised = FALSE;
2387 smtputf8_advertised = FALSE;
2390 /* Reset ACL connection variables */
2394 /* Allow for trailing 0 in the command and data buffers. */
2396 if (!(smtp_cmd_buffer = US malloc(2*SMTP_CMD_BUFFER_SIZE + 2)))
2397 log_write(0, LOG_MAIN|LOG_PANIC_DIE,
2398 "malloc() failed for SMTP command buffer");
2400 smtp_cmd_buffer[0] = 0;
2401 smtp_data_buffer = smtp_cmd_buffer + SMTP_CMD_BUFFER_SIZE + 1;
2403 /* For batched input, the protocol setting can be overridden from the
2404 command line by a trusted caller. */
2406 if (smtp_batched_input)
2408 if (!received_protocol) received_protocol = US"local-bsmtp";
2411 /* For non-batched SMTP input, the protocol setting is forced here. It will be
2412 reset later if any of EHLO/AUTH/STARTTLS are received. */
2416 (sender_host_address ? protocols : protocols_local) [pnormal];
2418 /* Set up the buffer for inputting using direct read() calls, and arrange to
2419 call the local functions instead of the standard C ones. */
2421 if (!(smtp_inbuffer = (uschar *)malloc(IN_BUFFER_SIZE)))
2422 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "malloc() failed for SMTP input buffer");
2424 receive_getc = smtp_getc;
2425 receive_getbuf = smtp_getbuf;
2426 receive_get_cache = smtp_get_cache;
2427 receive_ungetc = smtp_ungetc;
2428 receive_feof = smtp_feof;
2429 receive_ferror = smtp_ferror;
2430 receive_smtp_buffered = smtp_buffered;
2431 smtp_inptr = smtp_inend = smtp_inbuffer;
2432 smtp_had_eof = smtp_had_error = 0;
2434 /* Set up the message size limit; this may be host-specific */
2436 thismessage_size_limit = expand_string_integer(message_size_limit, TRUE);
2437 if (expand_string_message != NULL)
2439 if (thismessage_size_limit == -1)
2440 log_write(0, LOG_MAIN|LOG_PANIC, "unable to expand message_size_limit: "
2441 "%s", expand_string_message);
2443 log_write(0, LOG_MAIN|LOG_PANIC, "invalid message_size_limit: "
2444 "%s", expand_string_message);
2445 smtp_closedown(US"Temporary local problem - please try later");
2449 /* When a message is input locally via the -bs or -bS options, sender_host_
2450 unknown is set unless -oMa was used to force an IP address, in which case it
2451 is checked like a real remote connection. When -bs is used from inetd, this
2452 flag is not set, causing the sending host to be checked. The code that deals
2453 with IP source routing (if configured) is never required for -bs or -bS and
2454 the flag sender_host_notsocket is used to suppress it.
2456 If smtp_accept_max and smtp_accept_reserve are set, keep some connections in
2457 reserve for certain hosts and/or networks. */
2459 if (!sender_host_unknown)
2462 BOOL reserved_host = FALSE;
2464 /* Look up IP options (source routing info) on the socket if this is not an
2465 -oMa "host", and if any are found, log them and drop the connection.
2467 Linux (and others now, see below) is different to everyone else, so there
2468 has to be some conditional compilation here. Versions of Linux before 2.1.15
2469 used a structure whose name was "options". Somebody finally realized that
2470 this name was silly, and it got changed to "ip_options". I use the
2471 newer name here, but there is a fudge in the script that sets up os.h
2472 to define a macro in older Linux systems.
2474 Sigh. Linux is a fast-moving target. Another generation of Linux uses
2475 glibc 2, which has chosen ip_opts for the structure name. This is now
2476 really a glibc thing rather than a Linux thing, so the condition name
2477 has been changed to reflect this. It is relevant also to GNU/Hurd.
2479 Mac OS 10.x (Darwin) is like the later glibc versions, but without the
2480 setting of the __GLIBC__ macro, so we can't detect it automatically. There's
2481 a special macro defined in the os.h file.
2483 Some DGUX versions on older hardware appear not to support IP options at
2484 all, so there is now a general macro which can be set to cut out this
2487 How to do this properly in IPv6 is not yet known. */
2489 #if !HAVE_IPV6 && !defined(NO_IP_OPTIONS)
2491 #ifdef GLIBC_IP_OPTIONS
2492 #if (!defined __GLIBC__) || (__GLIBC__ < 2)
2497 #elif defined DARWIN_IP_OPTIONS
2503 if (!host_checking && !sender_host_notsocket)
2506 EXIM_SOCKLEN_T optlen = sizeof(struct ip_options) + MAX_IPOPTLEN;
2507 struct ip_options *ipopt = store_get(optlen);
2509 struct ip_opts ipoptblock;
2510 struct ip_opts *ipopt = &ipoptblock;
2511 EXIM_SOCKLEN_T optlen = sizeof(ipoptblock);
2513 struct ipoption ipoptblock;
2514 struct ipoption *ipopt = &ipoptblock;
2515 EXIM_SOCKLEN_T optlen = sizeof(ipoptblock);
2518 /* Occasional genuine failures of getsockopt() have been seen - for
2519 example, "reset by peer". Therefore, just log and give up on this
2520 call, unless the error is ENOPROTOOPT. This error is given by systems
2521 that have the interfaces but not the mechanism - e.g. GNU/Hurd at the time
2522 of writing. So for that error, carry on - we just can't do an IP options
2525 DEBUG(D_receive) debug_printf("checking for IP options\n");
2527 if (getsockopt(fileno(smtp_out), IPPROTO_IP, IP_OPTIONS, (uschar *)(ipopt),
2530 if (errno != ENOPROTOOPT)
2532 log_write(0, LOG_MAIN, "getsockopt() failed from %s: %s",
2533 host_and_ident(FALSE), strerror(errno));
2534 smtp_printf("451 SMTP service not available\r\n", FALSE);
2539 /* Deal with any IP options that are set. On the systems I have looked at,
2540 the value of MAX_IPOPTLEN has been 40, meaning that there should never be
2541 more logging data than will fit in big_buffer. Nevertheless, after somebody
2542 questioned this code, I've added in some paranoid checking. */
2544 else if (optlen > 0)
2546 uschar *p = big_buffer;
2547 uschar *pend = big_buffer + big_buffer_size;
2548 uschar *opt, *adptr;
2550 struct in_addr addr;
2553 uschar *optstart = (uschar *)(ipopt->__data);
2555 uschar *optstart = (uschar *)(ipopt->ip_opts);
2557 uschar *optstart = (uschar *)(ipopt->ipopt_list);
2560 DEBUG(D_receive) debug_printf("IP options exist\n");
2562 Ustrcpy(p, "IP options on incoming call:");
2565 for (opt = optstart; opt != NULL &&
2566 opt < (uschar *)(ipopt) + optlen;)
2580 if (!string_format(p, pend-p, " %s [@%s",
2581 (*opt == IPOPT_SSRR)? "SSRR" : "LSRR",
2583 inet_ntoa(*((struct in_addr *)(&(ipopt->faddr))))))
2585 inet_ntoa(ipopt->ip_dst)))
2587 inet_ntoa(ipopt->ipopt_dst)))
2595 optcount = (opt[1] - 3) / sizeof(struct in_addr);
2597 while (optcount-- > 0)
2599 memcpy(&addr, adptr, sizeof(addr));
2600 if (!string_format(p, pend - p - 1, "%s%s",
2601 (optcount == 0)? ":" : "@", inet_ntoa(addr)))
2607 adptr += sizeof(struct in_addr);
2616 if (pend - p < 4 + 3*opt[1]) { opt = NULL; break; }
2619 for (i = 0; i < opt[1]; i++)
2620 p += sprintf(CS p, "%2.2x ", opt[i]);
2629 log_write(0, LOG_MAIN, "%s", big_buffer);
2631 /* Refuse any call with IP options. This is what tcpwrappers 7.5 does. */
2633 log_write(0, LOG_MAIN|LOG_REJECT,
2634 "connection from %s refused (IP options)", host_and_ident(FALSE));
2636 smtp_printf("554 SMTP service not available\r\n", FALSE);
2640 /* Length of options = 0 => there are no options */
2642 else DEBUG(D_receive) debug_printf("no IP options found\n");
2644 #endif /* HAVE_IPV6 && !defined(NO_IP_OPTIONS) */
2646 /* Set keep-alive in socket options. The option is on by default. This
2647 setting is an attempt to get rid of some hanging connections that stick in
2648 read() when the remote end (usually a dialup) goes away. */
2650 if (smtp_accept_keepalive && !sender_host_notsocket)
2651 ip_keepalive(fileno(smtp_out), sender_host_address, FALSE);
2653 /* If the current host matches host_lookup, set the name by doing a
2654 reverse lookup. On failure, sender_host_name will be NULL and
2655 host_lookup_failed will be TRUE. This may or may not be serious - optional
2658 if (verify_check_host(&host_lookup) == OK)
2660 (void)host_name_lookup();
2661 host_build_sender_fullhost();
2664 /* Delay this until we have the full name, if it is looked up. */
2666 set_process_info("handling incoming connection from %s",
2667 host_and_ident(FALSE));
2669 /* Expand smtp_receive_timeout, if needed */
2671 if (smtp_receive_timeout_s)
2674 if ( !(exp = expand_string(smtp_receive_timeout_s))
2676 || (smtp_receive_timeout = readconf_readtime(exp, 0, FALSE)) < 0
2678 log_write(0, LOG_MAIN|LOG_PANIC,
2679 "bad value for smtp_receive_timeout: '%s'", exp ? exp : US"");
2682 /* Test for explicit connection rejection */
2684 if (verify_check_host(&host_reject_connection) == OK)
2686 log_write(L_connection_reject, LOG_MAIN|LOG_REJECT, "refused connection "
2687 "from %s (host_reject_connection)", host_and_ident(FALSE));
2688 smtp_printf("554 SMTP service not available\r\n", FALSE);
2692 /* Test with TCP Wrappers if so configured. There is a problem in that
2693 hosts_ctl() returns 0 (deny) under a number of system failure circumstances,
2694 such as disks dying. In these cases, it is desirable to reject with a 4xx
2695 error instead of a 5xx error. There isn't a "right" way to detect such
2696 problems. The following kludge is used: errno is zeroed before calling
2697 hosts_ctl(). If the result is "reject", a 5xx error is given only if the
2698 value of errno is 0 or ENOENT (which happens if /etc/hosts.{allow,deny} does
2701 #ifdef USE_TCP_WRAPPERS
2703 if (!(tcp_wrappers_name = expand_string(tcp_wrappers_daemon_name)))
2704 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "Expansion of \"%s\" "
2705 "(tcp_wrappers_name) failed: %s", string_printing(tcp_wrappers_name),
2706 expand_string_message);
2708 if (!hosts_ctl(tcp_wrappers_name,
2709 sender_host_name ? CS sender_host_name : STRING_UNKNOWN,
2710 sender_host_address ? CS sender_host_address : STRING_UNKNOWN,
2711 sender_ident ? CS sender_ident : STRING_UNKNOWN))
2713 if (errno == 0 || errno == ENOENT)
2715 HDEBUG(D_receive) debug_printf("tcp wrappers rejection\n");
2716 log_write(L_connection_reject,
2717 LOG_MAIN|LOG_REJECT, "refused connection from %s "
2718 "(tcp wrappers)", host_and_ident(FALSE));
2719 smtp_printf("554 SMTP service not available\r\n", FALSE);
2723 int save_errno = errno;
2724 HDEBUG(D_receive) debug_printf("tcp wrappers rejected with unexpected "
2725 "errno value %d\n", save_errno);
2726 log_write(L_connection_reject,
2727 LOG_MAIN|LOG_REJECT, "temporarily refused connection from %s "
2728 "(tcp wrappers errno=%d)", host_and_ident(FALSE), save_errno);
2729 smtp_printf("451 Temporary local problem - please try later\r\n", FALSE);
2735 /* Check for reserved slots. The value of smtp_accept_count has already been
2736 incremented to include this process. */
2738 if (smtp_accept_max > 0 &&
2739 smtp_accept_count > smtp_accept_max - smtp_accept_reserve)
2741 if ((rc = verify_check_host(&smtp_reserve_hosts)) != OK)
2743 log_write(L_connection_reject,
2744 LOG_MAIN, "temporarily refused connection from %s: not in "
2745 "reserve list: connected=%d max=%d reserve=%d%s",
2746 host_and_ident(FALSE), smtp_accept_count - 1, smtp_accept_max,
2747 smtp_accept_reserve, (rc == DEFER)? " (lookup deferred)" : "");
2748 smtp_printf("421 %s: Too many concurrent SMTP connections; "
2749 "please try again later\r\n", FALSE, smtp_active_hostname);
2752 reserved_host = TRUE;
2755 /* If a load level above which only messages from reserved hosts are
2756 accepted is set, check the load. For incoming calls via the daemon, the
2757 check is done in the superior process if there are no reserved hosts, to
2758 save a fork. In all cases, the load average will already be available
2759 in a global variable at this point. */
2761 if (smtp_load_reserve >= 0 &&
2762 load_average > smtp_load_reserve &&
2764 verify_check_host(&smtp_reserve_hosts) != OK)
2766 log_write(L_connection_reject,
2767 LOG_MAIN, "temporarily refused connection from %s: not in "
2768 "reserve list and load average = %.2f", host_and_ident(FALSE),
2769 (double)load_average/1000.0);
2770 smtp_printf("421 %s: Too much load; please try again later\r\n", FALSE,
2771 smtp_active_hostname);
2775 /* Determine whether unqualified senders or recipients are permitted
2776 for this host. Unfortunately, we have to do this every time, in order to
2777 set the flags so that they can be inspected when considering qualifying
2778 addresses in the headers. For a site that permits no qualification, this
2779 won't take long, however. */
2781 allow_unqualified_sender =
2782 verify_check_host(&sender_unqualified_hosts) == OK;
2784 allow_unqualified_recipient =
2785 verify_check_host(&recipient_unqualified_hosts) == OK;
2787 /* Determine whether HELO/EHLO is required for this host. The requirement
2788 can be hard or soft. */
2790 helo_required = verify_check_host(&helo_verify_hosts) == OK;
2792 helo_verify = verify_check_host(&helo_try_verify_hosts) == OK;
2794 /* Determine whether this hosts is permitted to send syntactic junk
2795 after a HELO or EHLO command. */
2797 helo_accept_junk = verify_check_host(&helo_accept_junk_hosts) == OK;
2800 /* For batch SMTP input we are now done. */
2802 if (smtp_batched_input) return TRUE;
2804 /* If valid Proxy Protocol source is connecting, set up session.
2805 * Failure will not allow any SMTP function other than QUIT. */
2807 #ifdef SUPPORT_PROXY
2808 proxy_session = FALSE;
2809 proxy_session_failed = FALSE;
2810 if (check_proxy_protocol_host())
2811 setup_proxy_protocol_host();
2814 /* Start up TLS if tls_on_connect is set. This is for supporting the legacy
2815 smtps port for use with older style SSL MTAs. */
2818 if (tls_in.on_connect && tls_server_start(tls_require_ciphers, &user_msg) != OK)
2819 return smtp_log_tls_fail(user_msg);
2822 /* Run the connect ACL if it exists */
2825 if (acl_smtp_connect)
2828 if ((rc = acl_check(ACL_WHERE_CONNECT, NULL, acl_smtp_connect, &user_msg,
2831 (void) smtp_handle_acl_fail(ACL_WHERE_CONNECT, rc, user_msg, log_msg);
2836 /* Output the initial message for a two-way SMTP connection. It may contain
2837 newlines, which then cause a multi-line response to be given. */
2839 code = US"220"; /* Default status code */
2840 esc = US""; /* Default extended status code */
2841 esclen = 0; /* Length of esc */
2845 if (!(s = expand_string(smtp_banner)))
2846 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "Expansion of \"%s\" (smtp_banner) "
2847 "failed: %s", smtp_banner, expand_string_message);
2853 smtp_message_code(&code, &codelen, &s, NULL, TRUE);
2857 esclen = codelen - 4;
2861 /* Remove any terminating newlines; might as well remove trailing space too */
2864 while (p > s && isspace(p[-1])) p--;
2867 /* It seems that CC:Mail is braindead, and assumes that the greeting message
2868 is all contained in a single IP packet. The original code wrote out the
2869 greeting using several calls to fprint/fputc, and on busy servers this could
2870 cause it to be split over more than one packet - which caused CC:Mail to fall
2871 over when it got the second part of the greeting after sending its first
2872 command. Sigh. To try to avoid this, build the complete greeting message
2873 first, and output it in one fell swoop. This gives a better chance of it
2874 ending up as a single packet. */
2876 ss = store_get(size);
2880 do /* At least once, in case we have an empty string */
2883 uschar *linebreak = Ustrchr(p, '\n');
2884 ss = string_catn(ss, &size, &ptr, code, 3);
2885 if (linebreak == NULL)
2888 ss = string_catn(ss, &size, &ptr, US" ", 1);
2892 len = linebreak - p;
2893 ss = string_catn(ss, &size, &ptr, US"-", 1);
2895 ss = string_catn(ss, &size, &ptr, esc, esclen);
2896 ss = string_catn(ss, &size, &ptr, p, len);
2897 ss = string_catn(ss, &size, &ptr, US"\r\n", 2);
2899 if (linebreak != NULL) p++;
2903 ss[ptr] = 0; /* string_cat leaves room for this */
2905 /* Before we write the banner, check that there is no input pending, unless
2906 this synchronisation check is disabled. */
2910 unsigned n = smtp_inend - smtp_inptr;
2913 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP protocol "
2914 "synchronization error (input sent without waiting for greeting): "
2915 "rejected connection from %s input=\"%s\"", host_and_ident(TRUE),
2916 string_printing(string_copyn(smtp_inptr, n)));
2917 smtp_printf("554 SMTP synchronization error\r\n", FALSE);
2921 /* Now output the banner */
2923 smtp_printf("%s", FALSE, ss);
2931 /*************************************************
2932 * Handle SMTP syntax and protocol errors *
2933 *************************************************/
2935 /* Write to the log for SMTP syntax errors in incoming commands, if configured
2936 to do so. Then transmit the error response. The return value depends on the
2937 number of syntax and protocol errors in this SMTP session.
2940 type error type, given as a log flag bit
2941 code response code; <= 0 means don't send a response
2942 data data to reflect in the response (can be NULL)
2943 errmess the error message
2945 Returns: -1 limit of syntax/protocol errors NOT exceeded
2946 +1 limit of syntax/protocol errors IS exceeded
2948 These values fit in with the values of the "done" variable in the main
2949 processing loop in smtp_setup_msg(). */
2952 synprot_error(int type, int code, uschar *data, uschar *errmess)
2956 log_write(type, LOG_MAIN, "SMTP %s error in \"%s\" %s %s",
2957 (type == L_smtp_syntax_error)? "syntax" : "protocol",
2958 string_printing(smtp_cmd_buffer), host_and_ident(TRUE), errmess);
2960 if (++synprot_error_count > smtp_max_synprot_errors)
2963 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
2964 "syntax or protocol errors (last command was \"%s\")",
2965 host_and_ident(FALSE), string_printing(smtp_cmd_buffer));
2970 smtp_printf("%d%c%s%s%s\r\n", FALSE, code, yield == 1 ? '-' : ' ',
2971 data ? data : US"", data ? US": " : US"", errmess);
2973 smtp_printf("%d Too many syntax or protocol errors\r\n", FALSE, code);
2982 /*************************************************
2983 * Send SMTP response, possibly multiline *
2984 *************************************************/
2986 /* There are, it seems, broken clients out there that cannot handle multiline
2987 responses. If no_multiline_responses is TRUE (it can be set from an ACL), we
2988 output nothing for non-final calls, and only the first line for anything else.
2991 code SMTP code, may involve extended status codes
2992 codelen length of smtp code; if > 4 there's an ESC
2993 final FALSE if the last line isn't the final line
2994 msg message text, possibly containing newlines
3000 smtp_respond(uschar* code, int codelen, BOOL final, uschar *msg)
3005 if (!final && no_multiline_responses) return;
3010 esclen = codelen - 4;
3013 /* If this is the first output for a (non-batch) RCPT command, see if all RCPTs
3014 have had the same. Note: this code is also present in smtp_printf(). It would
3015 be tidier to have it only in one place, but when it was added, it was easier to
3016 do it that way, so as not to have to mess with the code for the RCPT command,
3017 which sometimes uses smtp_printf() and sometimes smtp_respond(). */
3019 if (rcpt_in_progress)
3021 if (rcpt_smtp_response == NULL)
3022 rcpt_smtp_response = string_copy(msg);
3023 else if (rcpt_smtp_response_same &&
3024 Ustrcmp(rcpt_smtp_response, msg) != 0)
3025 rcpt_smtp_response_same = FALSE;
3026 rcpt_in_progress = FALSE;
3029 /* Now output the message, splitting it up into multiple lines if necessary.
3030 We only handle pipelining these responses as far as nonfinal/final groups,
3031 not the whole MAIL/RCPT/DATA response set. */
3035 uschar *nl = Ustrchr(msg, '\n');
3038 smtp_printf("%.3s%c%.*s%s\r\n", !final, code, final ? ' ':'-', esclen, esc, msg);
3041 else if (nl[1] == 0 || no_multiline_responses)
3043 smtp_printf("%.3s%c%.*s%.*s\r\n", !final, code, final ? ' ':'-', esclen, esc,
3044 (int)(nl - msg), msg);
3049 smtp_printf("%.3s-%.*s%.*s\r\n", TRUE, code, esclen, esc, (int)(nl - msg), msg);
3051 while (isspace(*msg)) msg++;
3059 /*************************************************
3060 * Parse user SMTP message *
3061 *************************************************/
3063 /* This function allows for user messages overriding the response code details
3064 by providing a suitable response code string at the start of the message
3065 user_msg. Check the message for starting with a response code and optionally an
3066 extended status code. If found, check that the first digit is valid, and if so,
3067 change the code pointer and length to use the replacement. An invalid code
3068 causes a panic log; in this case, if the log messages is the same as the user
3069 message, we must also adjust the value of the log message to show the code that
3070 is actually going to be used (the original one).
3072 This function is global because it is called from receive.c as well as within
3075 Note that the code length returned includes the terminating whitespace
3076 character, which is always included in the regex match.
3079 code SMTP code, may involve extended status codes
3080 codelen length of smtp code; if > 4 there's an ESC
3082 log_msg optional log message, to be adjusted with the new SMTP code
3083 check_valid if true, verify the response code
3089 smtp_message_code(uschar **code, int *codelen, uschar **msg, uschar **log_msg,
3095 if (!msg || !*msg) return;
3097 if ((n = pcre_exec(regex_smtp_code, NULL, CS *msg, Ustrlen(*msg), 0,
3098 PCRE_EOPT, ovector, sizeof(ovector)/sizeof(int))) < 0) return;
3100 if (check_valid && (*msg)[0] != (*code)[0])
3102 log_write(0, LOG_MAIN|LOG_PANIC, "configured error code starts with "
3103 "incorrect digit (expected %c) in \"%s\"", (*code)[0], *msg);
3104 if (log_msg != NULL && *log_msg == *msg)
3105 *log_msg = string_sprintf("%s %s", *code, *log_msg + ovector[1]);
3110 *codelen = ovector[1]; /* Includes final space */
3112 *msg += ovector[1]; /* Chop the code off the message */
3119 /*************************************************
3120 * Handle an ACL failure *
3121 *************************************************/
3123 /* This function is called when acl_check() fails. As well as calls from within
3124 this module, it is called from receive.c for an ACL after DATA. It sorts out
3125 logging the incident, and sets up the error response. A message containing
3126 newlines is turned into a multiline SMTP response, but for logging, only the
3129 There's a table of default permanent failure response codes to use in
3130 globals.c, along with the table of names. VFRY is special. Despite RFC1123 it
3131 defaults disabled in Exim. However, discussion in connection with RFC 821bis
3132 (aka RFC 2821) has concluded that the response should be 252 in the disabled
3133 state, because there are broken clients that try VRFY before RCPT. A 5xx
3134 response should be given only when the address is positively known to be
3135 undeliverable. Sigh. We return 252 if there is no VRFY ACL or it provides
3136 no explicit code, but if there is one we let it know best.
3137 Also, for ETRN, 458 is given on refusal, and for AUTH, 503.
3139 From Exim 4.63, it is possible to override the response code details by
3140 providing a suitable response code string at the start of the message provided
3141 in user_msg. The code's first digit is checked for validity.
3144 where where the ACL was called from
3146 user_msg a message that can be included in an SMTP response
3147 log_msg a message for logging
3149 Returns: 0 in most cases
3150 2 if the failure code was FAIL_DROP, in which case the
3151 SMTP connection should be dropped (this value fits with the
3152 "done" variable in smtp_setup_msg() below)
3156 smtp_handle_acl_fail(int where, int rc, uschar *user_msg, uschar *log_msg)
3158 BOOL drop = rc == FAIL_DROP;
3162 uschar *sender_info = US"";
3164 #ifdef WITH_CONTENT_SCAN
3165 where == ACL_WHERE_MIME ? US"during MIME ACL checks" :
3167 where == ACL_WHERE_PREDATA ? US"DATA" :
3168 where == ACL_WHERE_DATA ? US"after DATA" :
3169 #ifndef DISABLE_PRDR
3170 where == ACL_WHERE_PRDR ? US"after DATA PRDR" :
3173 string_sprintf("%s %s", acl_wherenames[where], smtp_cmd_data) :
3174 string_sprintf("%s in \"connect\" ACL", acl_wherenames[where]);
3176 if (drop) rc = FAIL;
3178 /* Set the default SMTP code, and allow a user message to change it. */
3180 smtp_code = rc == FAIL ? acl_wherecodes[where] : US"451";
3181 smtp_message_code(&smtp_code, &codelen, &user_msg, &log_msg,
3182 where != ACL_WHERE_VRFY);
3184 /* We used to have sender_address here; however, there was a bug that was not
3185 updating sender_address after a rewrite during a verify. When this bug was
3186 fixed, sender_address at this point became the rewritten address. I'm not sure
3187 this is what should be logged, so I've changed to logging the unrewritten
3188 address to retain backward compatibility. */
3190 #ifndef WITH_CONTENT_SCAN
3191 if (where == ACL_WHERE_RCPT || where == ACL_WHERE_DATA)
3193 if (where == ACL_WHERE_RCPT || where == ACL_WHERE_DATA || where == ACL_WHERE_MIME)
3196 sender_info = string_sprintf("F=<%s>%s%s%s%s ",
3197 sender_address_unrewritten ? sender_address_unrewritten : sender_address,
3198 sender_host_authenticated ? US" A=" : US"",
3199 sender_host_authenticated ? sender_host_authenticated : US"",
3200 sender_host_authenticated && authenticated_id ? US":" : US"",
3201 sender_host_authenticated && authenticated_id ? authenticated_id : US""
3205 /* If there's been a sender verification failure with a specific message, and
3206 we have not sent a response about it yet, do so now, as a preliminary line for
3207 failures, but not defers. However, always log it for defer, and log it for fail
3208 unless the sender_verify_fail log selector has been turned off. */
3210 if (sender_verified_failed &&
3211 !testflag(sender_verified_failed, af_sverify_told))
3213 BOOL save_rcpt_in_progress = rcpt_in_progress;
3214 rcpt_in_progress = FALSE; /* So as not to treat these as the error */
3216 setflag(sender_verified_failed, af_sverify_told);
3218 if (rc != FAIL || LOGGING(sender_verify_fail))
3219 log_write(0, LOG_MAIN|LOG_REJECT, "%s sender verify %s for <%s>%s",
3220 host_and_ident(TRUE),
3221 ((sender_verified_failed->special_action & 255) == DEFER)? "defer":"fail",
3222 sender_verified_failed->address,
3223 (sender_verified_failed->message == NULL)? US"" :
3224 string_sprintf(": %s", sender_verified_failed->message));
3226 if (rc == FAIL && sender_verified_failed->user_message)
3227 smtp_respond(smtp_code, codelen, FALSE, string_sprintf(
3228 testflag(sender_verified_failed, af_verify_pmfail)?
3229 "Postmaster verification failed while checking <%s>\n%s\n"
3230 "Several RFCs state that you are required to have a postmaster\n"
3231 "mailbox for each mail domain. This host does not accept mail\n"
3232 "from domains whose servers reject the postmaster address."
3234 testflag(sender_verified_failed, af_verify_nsfail)?
3235 "Callback setup failed while verifying <%s>\n%s\n"
3236 "The initial connection, or a HELO or MAIL FROM:<> command was\n"
3237 "rejected. Refusing MAIL FROM:<> does not help fight spam, disregards\n"
3238 "RFC requirements, and stops you from receiving standard bounce\n"
3239 "messages. This host does not accept mail from domains whose servers\n"
3242 "Verification failed for <%s>\n%s",
3243 sender_verified_failed->address,
3244 sender_verified_failed->user_message));
3246 rcpt_in_progress = save_rcpt_in_progress;
3249 /* Sort out text for logging */
3251 log_msg = log_msg ? string_sprintf(": %s", log_msg) : US"";
3252 if ((lognl = Ustrchr(log_msg, '\n'))) *lognl = 0;
3254 /* Send permanent failure response to the command, but the code used isn't
3255 always a 5xx one - see comments at the start of this function. If the original
3256 rc was FAIL_DROP we drop the connection and yield 2. */
3259 smtp_respond(smtp_code, codelen, TRUE,
3260 user_msg ? user_msg : US"Administrative prohibition");
3262 /* Send temporary failure response to the command. Don't give any details,
3263 unless acl_temp_details is set. This is TRUE for a callout defer, a "defer"
3264 verb, and for a header verify when smtp_return_error_details is set.
3266 This conditional logic is all somewhat of a mess because of the odd
3267 interactions between temp_details and return_error_details. One day it should
3268 be re-implemented in a tidier fashion. */
3271 if (acl_temp_details && user_msg)
3273 if ( smtp_return_error_details
3274 && sender_verified_failed
3275 && sender_verified_failed->message
3277 smtp_respond(smtp_code, codelen, FALSE, sender_verified_failed->message);
3279 smtp_respond(smtp_code, codelen, TRUE, user_msg);
3282 smtp_respond(smtp_code, codelen, TRUE,
3283 US"Temporary local problem - please try later");
3285 /* Log the incident to the logs that are specified by log_reject_target
3286 (default main, reject). This can be empty to suppress logging of rejections. If
3287 the connection is not forcibly to be dropped, return 0. Otherwise, log why it
3288 is closing if required and return 2. */
3290 if (log_reject_target != 0)
3293 uschar * tls = s_tlslog(NULL, NULL, NULL);
3294 if (!tls) tls = US"";
3296 uschar * tls = US"";
3298 log_write(where == ACL_WHERE_CONNECT ? L_connection_reject : 0,
3299 log_reject_target, "%s%s%s %s%srejected %s%s",
3300 LOGGING(dnssec) && sender_host_dnssec ? US" DS" : US"",
3301 host_and_ident(TRUE),
3304 rc == FAIL ? US"" : US"temporarily ",
3308 if (!drop) return 0;
3310 log_write(L_smtp_connection, LOG_MAIN, "%s closed by DROP in ACL",
3311 smtp_get_connection_info());
3313 /* Run the not-quit ACL, but without any custom messages. This should not be a
3314 problem, because we get here only if some other ACL has issued "drop", and
3315 in that case, *its* custom messages will have been used above. */
3317 smtp_notquit_exit(US"acl-drop", NULL, NULL);
3324 /*************************************************
3325 * Handle SMTP exit when QUIT is not given *
3326 *************************************************/
3328 /* This function provides a logging/statistics hook for when an SMTP connection
3329 is dropped on the floor or the other end goes away. It's a global function
3330 because it's called from receive.c as well as this module. As well as running
3331 the NOTQUIT ACL, if there is one, this function also outputs a final SMTP
3332 response, either with a custom message from the ACL, or using a default. There
3333 is one case, however, when no message is output - after "drop". In that case,
3334 the ACL that obeyed "drop" has already supplied the custom message, and NULL is
3335 passed to this function.
3337 In case things go wrong while processing this function, causing an error that
3338 may re-enter this function, there is a recursion check.
3341 reason What $smtp_notquit_reason will be set to in the ACL;
3342 if NULL, the ACL is not run
3343 code The error code to return as part of the response
3344 defaultrespond The default message if there's no user_msg
3350 smtp_notquit_exit(uschar *reason, uschar *code, uschar *defaultrespond, ...)
3353 uschar *user_msg = NULL;
3354 uschar *log_msg = NULL;
3356 /* Check for recursive acll */
3358 if (smtp_exit_function_called)
3360 log_write(0, LOG_PANIC, "smtp_notquit_exit() called more than once (%s)",
3364 smtp_exit_function_called = TRUE;
3366 /* Call the not-QUIT ACL, if there is one, unless no reason is given. */
3368 if (acl_smtp_notquit && reason)
3370 smtp_notquit_reason = reason;
3371 if ((rc = acl_check(ACL_WHERE_NOTQUIT, NULL, acl_smtp_notquit, &user_msg,
3372 &log_msg)) == ERROR)
3373 log_write(0, LOG_MAIN|LOG_PANIC, "ACL for not-QUIT returned ERROR: %s",
3377 /* Write an SMTP response if we are expected to give one. As the default
3378 responses are all internal, they should always fit in the buffer, but code a
3379 warning, just in case. Note that string_vformat() still leaves a complete
3380 string, even if it is incomplete. */
3382 if (code && defaultrespond)
3385 smtp_respond(code, 3, TRUE, user_msg);
3390 va_start(ap, defaultrespond);
3391 if (!string_vformat(buffer, sizeof(buffer), CS defaultrespond, ap))
3392 log_write(0, LOG_MAIN|LOG_PANIC, "string too large in smtp_notquit_exit()");
3393 smtp_printf("%s %s\r\n", FALSE, code, buffer);
3403 /*************************************************
3404 * Verify HELO argument *
3405 *************************************************/
3407 /* This function is called if helo_verify_hosts or helo_try_verify_hosts is
3408 matched. It is also called from ACL processing if verify = helo is used and
3409 verification was not previously tried (i.e. helo_try_verify_hosts was not
3410 matched). The result of its processing is to set helo_verified and
3411 helo_verify_failed. These variables should both be FALSE for this function to
3414 Note that EHLO/HELO is legitimately allowed to quote an address literal. Allow
3415 for IPv6 ::ffff: literals.
3418 Returns: TRUE if testing was completed;
3419 FALSE on a temporary failure
3423 smtp_verify_helo(void)
3427 HDEBUG(D_receive) debug_printf("verifying EHLO/HELO argument \"%s\"\n",
3430 if (sender_helo_name == NULL)
3432 HDEBUG(D_receive) debug_printf("no EHLO/HELO command was issued\n");
3435 /* Deal with the case of -bs without an IP address */
3437 else if (sender_host_address == NULL)
3439 HDEBUG(D_receive) debug_printf("no client IP address: assume success\n");
3440 helo_verified = TRUE;
3443 /* Deal with the more common case when there is a sending IP address */
3445 else if (sender_helo_name[0] == '[')
3447 helo_verified = Ustrncmp(sender_helo_name+1, sender_host_address,
3448 Ustrlen(sender_host_address)) == 0;
3453 if (strncmpic(sender_host_address, US"::ffff:", 7) == 0)
3454 helo_verified = Ustrncmp(sender_helo_name + 1,
3455 sender_host_address + 7, Ustrlen(sender_host_address) - 7) == 0;
3460 { if (helo_verified) debug_printf("matched host address\n"); }
3463 /* Do a reverse lookup if one hasn't already given a positive or negative
3464 response. If that fails, or the name doesn't match, try checking with a forward
3469 if (sender_host_name == NULL && !host_lookup_failed)
3470 yield = host_name_lookup() != DEFER;
3472 /* If a host name is known, check it and all its aliases. */
3474 if (sender_host_name)
3475 if ((helo_verified = strcmpic(sender_host_name, sender_helo_name) == 0))
3477 sender_helo_dnssec = sender_host_dnssec;
3478 HDEBUG(D_receive) debug_printf("matched host name\n");
3482 uschar **aliases = sender_host_aliases;
3484 if ((helo_verified = strcmpic(*aliases++, sender_helo_name) == 0))
3486 sender_helo_dnssec = sender_host_dnssec;
3490 HDEBUG(D_receive) if (helo_verified)
3491 debug_printf("matched alias %s\n", *(--aliases));
3494 /* Final attempt: try a forward lookup of the helo name */
3503 h.name = sender_helo_name;
3510 HDEBUG(D_receive) debug_printf("getting IP address for %s\n",
3512 rc = host_find_bydns(&h, NULL, HOST_FIND_BY_A,
3513 NULL, NULL, NULL, &d, NULL, NULL);
3514 if (rc == HOST_FOUND || rc == HOST_FOUND_LOCAL)
3515 for (hh = &h; hh; hh = hh->next)
3516 if (Ustrcmp(hh->address, sender_host_address) == 0)
3518 helo_verified = TRUE;
3519 if (h.dnssec == DS_YES) sender_helo_dnssec = TRUE;
3522 debug_printf("IP address for %s matches calling address\n"
3523 "Forward DNS security status: %sverified\n",
3524 sender_helo_name, sender_helo_dnssec ? "" : "un");
3531 if (!helo_verified) helo_verify_failed = TRUE; /* We've tried ... */
3538 /*************************************************
3539 * Send user response message *
3540 *************************************************/
3542 /* This function is passed a default response code and a user message. It calls
3543 smtp_message_code() to check and possibly modify the response code, and then
3544 calls smtp_respond() to transmit the response. I put this into a function
3545 just to avoid a lot of repetition.
3548 code the response code
3549 user_msg the user message
3555 smtp_user_msg(uschar *code, uschar *user_msg)
3558 smtp_message_code(&code, &len, &user_msg, NULL, TRUE);
3559 smtp_respond(code, len, TRUE, user_msg);
3565 smtp_in_auth(auth_instance *au, uschar ** s, uschar ** ss)
3567 const uschar *set_id = NULL;
3570 /* Run the checking code, passing the remainder of the command line as
3571 data. Initials the $auth<n> variables as empty. Initialize $0 empty and set
3572 it as the only set numerical variable. The authenticator may set $auth<n>
3573 and also set other numeric variables. The $auth<n> variables are preferred
3574 nowadays; the numerical variables remain for backwards compatibility.
3576 Afterwards, have a go at expanding the set_id string, even if
3577 authentication failed - for bad passwords it can be useful to log the
3578 userid. On success, require set_id to expand and exist, and put it in
3579 authenticated_id. Save this in permanent store, as the working store gets
3580 reset at HELO, RSET, etc. */
3582 for (i = 0; i < AUTH_VARS; i++) auth_vars[i] = NULL;
3584 expand_nlength[0] = 0; /* $0 contains nothing */
3586 rc = (au->info->servercode)(au, smtp_cmd_data);
3587 if (au->set_id) set_id = expand_string(au->set_id);
3588 expand_nmax = -1; /* Reset numeric variables */
3589 for (i = 0; i < AUTH_VARS; i++) auth_vars[i] = NULL; /* Reset $auth<n> */
3591 /* The value of authenticated_id is stored in the spool file and printed in
3592 log lines. It must not contain binary zeros or newline characters. In
3593 normal use, it never will, but when playing around or testing, this error
3594 can (did) happen. To guard against this, ensure that the id contains only
3595 printing characters. */
3597 if (set_id) set_id = string_printing(set_id);
3599 /* For the non-OK cases, set up additional logging data if set_id
3603 set_id = set_id && *set_id
3604 ? string_sprintf(" (set_id=%s)", set_id) : US"";
3606 /* Switch on the result */
3611 if (!au->set_id || set_id) /* Complete success */
3613 if (set_id) authenticated_id = string_copy_malloc(set_id);
3614 sender_host_authenticated = au->name;
3615 authentication_failed = FALSE;
3616 authenticated_fail_id = NULL; /* Impossible to already be set? */
3619 (sender_host_address ? protocols : protocols_local)
3620 [pextend + pauthed + (tls_in.active >= 0 ? pcrpted:0)];
3621 *s = *ss = US"235 Authentication succeeded";
3622 authenticated_by = au;
3626 /* Authentication succeeded, but we failed to expand the set_id string.
3627 Treat this as a temporary error. */
3629 auth_defer_msg = expand_string_message;
3633 if (set_id) authenticated_fail_id = string_copy_malloc(set_id);
3634 *s = string_sprintf("435 Unable to authenticate at present%s",
3635 auth_defer_user_msg);
3636 *ss = string_sprintf("435 Unable to authenticate at present%s: %s",
3637 set_id, auth_defer_msg);
3641 *s = *ss = US"501 Invalid base64 data";
3645 *s = *ss = US"501 Authentication cancelled";
3649 *s = *ss = US"553 Initial data not expected";
3653 if (set_id) authenticated_fail_id = string_copy_malloc(set_id);
3654 *s = US"535 Incorrect authentication data";
3655 *ss = string_sprintf("535 Incorrect authentication data%s", set_id);
3659 if (set_id) authenticated_fail_id = string_copy_malloc(set_id);
3660 *s = US"435 Internal error";
3661 *ss = string_sprintf("435 Internal error%s: return %d from authentication "
3662 "check", set_id, rc);
3674 qualify_recipient(uschar ** recipient, uschar * smtp_cmd_data, uschar * tag)
3677 if (allow_unqualified_recipient || strcmpic(*recipient, US"postmaster") == 0)
3679 DEBUG(D_receive) debug_printf("unqualified address %s accepted\n",
3681 rd = Ustrlen(recipient) + 1;
3682 *recipient = rewrite_address_qualify(*recipient, TRUE);
3685 smtp_printf("501 %s: recipient address must contain a domain\r\n", FALSE,
3687 log_write(L_smtp_syntax_error,
3688 LOG_MAIN|LOG_REJECT, "unqualified %s rejected: <%s> %s%s",
3689 tag, *recipient, host_and_ident(TRUE), host_lookup_msg);
3697 smtp_quit_handler(uschar ** user_msgp, uschar ** log_msgp)
3700 incomplete_transaction_log(US"QUIT");
3703 int rc = acl_check(ACL_WHERE_QUIT, NULL, acl_smtp_quit, user_msgp, log_msgp);
3705 log_write(0, LOG_MAIN|LOG_PANIC, "ACL for QUIT returned ERROR: %s",
3709 smtp_respond(US"221", 3, TRUE, *user_msgp);
3711 smtp_printf("221 %s closing connection\r\n", FALSE, smtp_active_hostname);
3714 tls_close(TRUE, TRUE);
3717 log_write(L_smtp_connection, LOG_MAIN, "%s closed by QUIT",
3718 smtp_get_connection_info());
3723 smtp_rset_handler(void)
3726 incomplete_transaction_log(US"RSET");
3727 smtp_printf("250 Reset OK\r\n", FALSE);
3728 cmd_list[CMD_LIST_RSET].is_mail_cmd = FALSE;
3733 /*************************************************
3734 * Initialize for SMTP incoming message *
3735 *************************************************/
3737 /* This function conducts the initial dialogue at the start of an incoming SMTP
3738 message, and builds a list of recipients. However, if the incoming message
3739 is part of a batch (-bS option) a separate function is called since it would
3740 be messy having tests splattered about all over this function. This function
3741 therefore handles the case where interaction is occurring. The input and output
3742 files are set up in smtp_in and smtp_out.
3744 The global recipients_list is set to point to a vector of recipient_item
3745 blocks, whose number is given by recipients_count. This is extended by the
3746 receive_add_recipient() function. The global variable sender_address is set to
3747 the sender's address. The yield is +1 if a message has been successfully
3748 started, 0 if a QUIT command was encountered or the connection was refused from
3749 the particular host, or -1 if the connection was lost.
3753 Returns: > 0 message successfully started (reached DATA)
3754 = 0 QUIT read or end of file reached or call refused
3759 smtp_setup_msg(void)
3762 BOOL toomany = FALSE;
3763 BOOL discarded = FALSE;
3764 BOOL last_was_rej_mail = FALSE;
3765 BOOL last_was_rcpt = FALSE;
3766 void *reset_point = store_get(0);
3768 DEBUG(D_receive) debug_printf("smtp_setup_msg entered\n");
3770 /* Reset for start of new message. We allow one RSET not to be counted as a
3771 nonmail command, for those MTAs that insist on sending it between every
3772 message. Ditto for EHLO/HELO and for STARTTLS, to allow for going in and out of
3773 TLS between messages (an Exim client may do this if it has messages queued up
3774 for the host). Note: we do NOT reset AUTH at this point. */
3776 smtp_reset(reset_point);
3777 message_ended = END_NOTSTARTED;
3779 chunking_state = chunking_offered ? CHUNKING_OFFERED : CHUNKING_NOT_OFFERED;
3781 cmd_list[CMD_LIST_RSET].is_mail_cmd = TRUE;
3782 cmd_list[CMD_LIST_HELO].is_mail_cmd = TRUE;
3783 cmd_list[CMD_LIST_EHLO].is_mail_cmd = TRUE;
3785 cmd_list[CMD_LIST_STARTTLS].is_mail_cmd = TRUE;
3786 cmd_list[CMD_LIST_TLS_AUTH].is_mail_cmd = TRUE;
3789 /* Set the local signal handler for SIGTERM - it tries to end off tidily */
3791 os_non_restarting_signal(SIGTERM, command_sigterm_handler);
3793 /* Batched SMTP is handled in a different function. */
3795 if (smtp_batched_input) return smtp_setup_batch_msg();
3797 /* Deal with SMTP commands. This loop is exited by setting done to a POSITIVE
3798 value. The values are 2 larger than the required yield of the function. */
3802 const uschar **argv;
3803 uschar *etrn_command;
3804 uschar *etrn_serialize_key;
3806 uschar *log_msg, *smtp_code;
3807 uschar *user_msg = NULL;
3808 uschar *recipient = NULL;
3809 uschar *hello = NULL;
3811 BOOL was_rej_mail = FALSE;
3812 BOOL was_rcpt = FALSE;
3813 void (*oldsignal)(int);
3815 int start, end, sender_domain, recipient_domain;
3819 uschar *orcpt = NULL;
3823 /* Check once per STARTTLS or SSL-on-connect for a TLS AUTH */
3824 if ( tls_in.active >= 0
3826 && tls_in.certificate_verified
3827 && cmd_list[CMD_LIST_TLS_AUTH].is_mail_cmd
3830 cmd_list[CMD_LIST_TLS_AUTH].is_mail_cmd = FALSE;
3832 && (rc = acl_check(ACL_WHERE_AUTH, NULL, acl_smtp_auth,
3833 &user_msg, &log_msg)) != OK
3836 done = smtp_handle_acl_fail(ACL_WHERE_AUTH, rc, user_msg, log_msg);
3840 for (au = auths; au; au = au->next)
3841 if (strcmpic(US"tls", au->driver_name) == 0)
3843 smtp_cmd_data = NULL;
3845 if (smtp_in_auth(au, &s, &ss) == OK)
3846 { DEBUG(D_auth) debug_printf("tls auth succeeded\n"); }
3848 { DEBUG(D_auth) debug_printf("tls auth not succeeded\n"); }
3855 if (smtp_in) /* Avoid pure-ACKs while in cmd pingpong phase */
3856 (void) setsockopt(fileno(smtp_in), IPPROTO_TCP, TCP_QUICKACK,
3857 US &off, sizeof(off));
3860 switch(smtp_read_command(TRUE, GETC_BUFFER_UNLIMITED))
3862 /* The AUTH command is not permitted to occur inside a transaction, and may
3863 occur successfully only once per connection. Actually, that isn't quite
3864 true. When TLS is started, all previous information about a connection must
3865 be discarded, so a new AUTH is permitted at that time.
3867 AUTH may only be used when it has been advertised. However, it seems that
3868 there are clients that send AUTH when it hasn't been advertised, some of
3869 them even doing this after HELO. And there are MTAs that accept this. Sigh.
3870 So there's a get-out that allows this to happen.
3872 AUTH is initially labelled as a "nonmail command" so that one occurrence
3873 doesn't get counted. We change the label here so that multiple failing
3874 AUTHS will eventually hit the nonmail threshold. */
3878 authentication_failed = TRUE;
3879 cmd_list[CMD_LIST_AUTH].is_mail_cmd = FALSE;
3881 if (!auth_advertised && !allow_auth_unadvertised)
3883 done = synprot_error(L_smtp_protocol_error, 503, NULL,
3884 US"AUTH command used when not advertised");
3887 if (sender_host_authenticated)
3889 done = synprot_error(L_smtp_protocol_error, 503, NULL,
3890 US"already authenticated");
3895 done = synprot_error(L_smtp_protocol_error, 503, NULL,
3896 US"not permitted in mail transaction");
3903 && (rc = acl_check(ACL_WHERE_AUTH, NULL, acl_smtp_auth,
3904 &user_msg, &log_msg)) != OK
3907 done = smtp_handle_acl_fail(ACL_WHERE_AUTH, rc, user_msg, log_msg);
3911 /* Find the name of the requested authentication mechanism. */
3914 while ((c = *smtp_cmd_data) != 0 && !isspace(c))
3916 if (!isalnum(c) && c != '-' && c != '_')
3918 done = synprot_error(L_smtp_syntax_error, 501, NULL,
3919 US"invalid character in authentication mechanism name");
3925 /* If not at the end of the line, we must be at white space. Terminate the
3926 name and move the pointer on to any data that may be present. */
3928 if (*smtp_cmd_data != 0)
3930 *smtp_cmd_data++ = 0;
3931 while (isspace(*smtp_cmd_data)) smtp_cmd_data++;
3934 /* Search for an authentication mechanism which is configured for use
3935 as a server and which has been advertised (unless, sigh, allow_auth_
3936 unadvertised is set). */
3938 for (au = auths; au; au = au->next)
3939 if (strcmpic(s, au->public_name) == 0 && au->server &&
3940 (au->advertised || allow_auth_unadvertised))
3945 c = smtp_in_auth(au, &s, &ss);
3947 smtp_printf("%s\r\n", FALSE, s);
3949 log_write(0, LOG_MAIN|LOG_REJECT, "%s authenticator failed for %s: %s",
3950 au->name, host_and_ident(FALSE), ss);
3953 done = synprot_error(L_smtp_protocol_error, 504, NULL,
3954 string_sprintf("%s authentication mechanism not supported", s));
3956 break; /* AUTH_CMD */
3958 /* The HELO/EHLO commands are permitted to appear in the middle of a
3959 session as well as at the beginning. They have the effect of a reset in
3960 addition to their other functions. Their absence at the start cannot be
3961 taken to be an error.
3965 If the EHLO command is not acceptable to the SMTP server, 501, 500,
3966 or 502 failure replies MUST be returned as appropriate. The SMTP
3967 server MUST stay in the same state after transmitting these replies
3968 that it was in before the EHLO was received.
3970 Therefore, we do not do the reset until after checking the command for
3971 acceptability. This change was made for Exim release 4.11. Previously
3972 it did the reset first. */
3985 HELO_EHLO: /* Common code for HELO and EHLO */
3986 cmd_list[CMD_LIST_HELO].is_mail_cmd = FALSE;
3987 cmd_list[CMD_LIST_EHLO].is_mail_cmd = FALSE;
3989 /* Reject the HELO if its argument was invalid or non-existent. A
3990 successful check causes the argument to be saved in malloc store. */
3992 if (!check_helo(smtp_cmd_data))
3994 smtp_printf("501 Syntactically invalid %s argument(s)\r\n", FALSE, hello);
3996 log_write(0, LOG_MAIN|LOG_REJECT, "rejected %s from %s: syntactically "
3997 "invalid argument(s): %s", hello, host_and_ident(FALSE),
3998 (*smtp_cmd_argument == 0)? US"(no argument given)" :
3999 string_printing(smtp_cmd_argument));
4001 if (++synprot_error_count > smtp_max_synprot_errors)
4003 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
4004 "syntax or protocol errors (last command was \"%s\")",
4005 host_and_ident(FALSE), string_printing(smtp_cmd_buffer));
4012 /* If sender_host_unknown is true, we have got here via the -bs interface,
4013 not called from inetd. Otherwise, we are running an IP connection and the
4014 host address will be set. If the helo name is the primary name of this
4015 host and we haven't done a reverse lookup, force one now. If helo_required
4016 is set, ensure that the HELO name matches the actual host. If helo_verify
4017 is set, do the same check, but softly. */
4019 if (!sender_host_unknown)
4021 BOOL old_helo_verified = helo_verified;
4022 uschar *p = smtp_cmd_data;
4024 while (*p != 0 && !isspace(*p)) { *p = tolower(*p); p++; }
4027 /* Force a reverse lookup if HELO quoted something in helo_lookup_domains
4028 because otherwise the log can be confusing. */
4030 if (sender_host_name == NULL &&
4031 (deliver_domain = sender_helo_name, /* set $domain */
4032 match_isinlist(sender_helo_name, CUSS &helo_lookup_domains, 0,
4033 &domainlist_anchor, NULL, MCL_DOMAIN, TRUE, NULL)) == OK)
4034 (void)host_name_lookup();
4036 /* Rebuild the fullhost info to include the HELO name (and the real name
4037 if it was looked up.) */
4039 host_build_sender_fullhost(); /* Rebuild */
4040 set_process_info("handling%s incoming connection from %s",
4041 (tls_in.active >= 0)? " TLS" : "", host_and_ident(FALSE));
4043 /* Verify if configured. This doesn't give much security, but it does
4044 make some people happy to be able to do it. If helo_required is set,
4045 (host matches helo_verify_hosts) failure forces rejection. If helo_verify
4046 is set (host matches helo_try_verify_hosts), it does not. This is perhaps
4047 now obsolescent, since the verification can now be requested selectively
4050 helo_verified = helo_verify_failed = sender_helo_dnssec = FALSE;
4051 if (helo_required || helo_verify)
4053 BOOL tempfail = !smtp_verify_helo();
4058 smtp_printf("%d %s argument does not match calling host\r\n", FALSE,
4059 tempfail? 451 : 550, hello);
4060 log_write(0, LOG_MAIN|LOG_REJECT, "%srejected \"%s %s\" from %s",
4061 tempfail? "temporarily " : "",
4062 hello, sender_helo_name, host_and_ident(FALSE));
4063 helo_verified = old_helo_verified;
4064 break; /* End of HELO/EHLO processing */
4066 HDEBUG(D_all) debug_printf("%s verification failed but host is in "
4067 "helo_try_verify_hosts\n", hello);
4072 #ifdef EXPERIMENTAL_SPF
4073 /* set up SPF context */
4074 spf_init(sender_helo_name, sender_host_address);
4077 /* Apply an ACL check if one is defined; afterwards, recheck
4078 synchronization in case the client started sending in a delay. */
4081 if ((rc = acl_check(ACL_WHERE_HELO, NULL, acl_smtp_helo,
4082 &user_msg, &log_msg)) != OK)
4084 done = smtp_handle_acl_fail(ACL_WHERE_HELO, rc, user_msg, log_msg);
4085 sender_helo_name = NULL;
4086 host_build_sender_fullhost(); /* Rebuild */
4089 else if (!check_sync()) goto SYNC_FAILURE;
4091 /* Generate an OK reply. The default string includes the ident if present,
4092 and also the IP address if present. Reflecting back the ident is intended
4093 as a deterrent to mail forgers. For maximum efficiency, and also because
4094 some broken systems expect each response to be in a single packet, arrange
4095 that the entire reply is sent in one write(). */
4097 auth_advertised = FALSE;
4098 pipelining_advertised = FALSE;
4100 tls_advertised = FALSE;
4102 dsn_advertised = FALSE;
4104 smtputf8_advertised = FALSE;
4107 smtp_code = US"250 "; /* Default response code plus space*/
4110 s = string_sprintf("%.3s %s Hello %s%s%s",
4112 smtp_active_hostname,
4113 sender_ident ? sender_ident : US"",
4114 sender_ident ? US" at " : US"",
4115 sender_host_name ? sender_host_name : sender_helo_name);
4120 if (sender_host_address)
4122 s = string_catn(s, &size, &ptr, US" [", 2);
4123 s = string_cat (s, &size, &ptr, sender_host_address);
4124 s = string_catn(s, &size, &ptr, US"]", 1);
4128 /* A user-supplied EHLO greeting may not contain more than one line. Note
4129 that the code returned by smtp_message_code() includes the terminating
4130 whitespace character. */
4136 smtp_message_code(&smtp_code, &codelen, &user_msg, NULL, TRUE);
4137 s = string_sprintf("%.*s%s", codelen, smtp_code, user_msg);
4138 if ((ss = strpbrk(CS s, "\r\n")) != NULL)
4140 log_write(0, LOG_MAIN|LOG_PANIC, "EHLO/HELO response must not contain "
4141 "newlines: message truncated: %s", string_printing(s));
4148 s = string_catn(s, &size, &ptr, US"\r\n", 2);
4150 /* If we received EHLO, we must create a multiline response which includes
4151 the functions supported. */
4157 /* I'm not entirely happy with this, as an MTA is supposed to check
4158 that it has enough room to accept a message of maximum size before
4159 it sends this. However, there seems little point in not sending it.
4160 The actual size check happens later at MAIL FROM time. By postponing it
4161 till then, VRFY and EXPN can be used after EHLO when space is short. */
4163 if (thismessage_size_limit > 0)
4165 sprintf(CS big_buffer, "%.3s-SIZE %d\r\n", smtp_code,
4166 thismessage_size_limit);
4167 s = string_cat(s, &size, &ptr, big_buffer);
4171 s = string_catn(s, &size, &ptr, smtp_code, 3);
4172 s = string_catn(s, &size, &ptr, US"-SIZE\r\n", 7);
4175 /* Exim does not do protocol conversion or data conversion. It is 8-bit
4176 clean; if it has an 8-bit character in its hand, it just sends it. It
4177 cannot therefore specify 8BITMIME and remain consistent with the RFCs.
4178 However, some users want this option simply in order to stop MUAs
4179 mangling messages that contain top-bit-set characters. It is therefore
4180 provided as an option. */
4182 if (accept_8bitmime)
4184 s = string_catn(s, &size, &ptr, smtp_code, 3);
4185 s = string_catn(s, &size, &ptr, US"-8BITMIME\r\n", 11);
4188 /* Advertise DSN support if configured to do so. */
4189 if (verify_check_host(&dsn_advertise_hosts) != FAIL)
4191 s = string_catn(s, &size, &ptr, smtp_code, 3);
4192 s = string_catn(s, &size, &ptr, US"-DSN\r\n", 6);
4193 dsn_advertised = TRUE;
4196 /* Advertise ETRN/VRFY/EXPN if there's are ACL checking whether a host is
4197 permitted to issue them; a check is made when any host actually tries. */
4201 s = string_catn(s, &size, &ptr, smtp_code, 3);
4202 s = string_catn(s, &size, &ptr, US"-ETRN\r\n", 7);
4206 s = string_catn(s, &size, &ptr, smtp_code, 3);
4207 s = string_catn(s, &size, &ptr, US"-VRFY\r\n", 7);
4211 s = string_catn(s, &size, &ptr, smtp_code, 3);
4212 s = string_catn(s, &size, &ptr, US"-EXPN\r\n", 7);
4215 /* Exim is quite happy with pipelining, so let the other end know that
4216 it is safe to use it, unless advertising is disabled. */
4218 if (pipelining_enable &&
4219 verify_check_host(&pipelining_advertise_hosts) == OK)
4221 s = string_catn(s, &size, &ptr, smtp_code, 3);
4222 s = string_catn(s, &size, &ptr, US"-PIPELINING\r\n", 13);
4223 sync_cmd_limit = NON_SYNC_CMD_PIPELINING;
4224 pipelining_advertised = TRUE;
4228 /* If any server authentication mechanisms are configured, advertise
4229 them if the current host is in auth_advertise_hosts. The problem with
4230 advertising always is that some clients then require users to
4231 authenticate (and aren't configurable otherwise) even though it may not
4232 be necessary (e.g. if the host is in host_accept_relay).
4234 RFC 2222 states that SASL mechanism names contain only upper case
4235 letters, so output the names in upper case, though we actually recognize
4236 them in either case in the AUTH command. */
4240 && !sender_host_authenticated
4242 && verify_check_host(&auth_advertise_hosts) == OK
4247 for (au = auths; au; au = au->next)
4249 au->advertised = FALSE;
4252 DEBUG(D_auth+D_expand) debug_printf_indent(
4253 "Evaluating advertise_condition for %s athenticator\n",
4255 if ( !au->advertise_condition
4256 || expand_check_condition(au->advertise_condition, au->name,
4263 s = string_catn(s, &size, &ptr, smtp_code, 3);
4264 s = string_catn(s, &size, &ptr, US"-AUTH", 5);
4266 auth_advertised = TRUE;
4269 s = string_catn(s, &size, &ptr, US" ", 1);
4270 s = string_cat (s, &size, &ptr, au->public_name);
4271 while (++saveptr < ptr) s[saveptr] = toupper(s[saveptr]);
4272 au->advertised = TRUE;
4277 if (!first) s = string_catn(s, &size, &ptr, US"\r\n", 2);
4280 /* RFC 3030 CHUNKING */
4282 if (verify_check_host(&chunking_advertise_hosts) != FAIL)
4284 s = string_catn(s, &size, &ptr, smtp_code, 3);
4285 s = string_catn(s, &size, &ptr, US"-CHUNKING\r\n", 11);
4286 chunking_offered = TRUE;
4287 chunking_state = CHUNKING_OFFERED;
4290 /* Advertise TLS (Transport Level Security) aka SSL (Secure Socket Layer)
4291 if it has been included in the binary, and the host matches
4292 tls_advertise_hosts. We must *not* advertise if we are already in a
4293 secure connection. */
4296 if (tls_in.active < 0 &&
4297 verify_check_host(&tls_advertise_hosts) != FAIL)
4299 s = string_catn(s, &size, &ptr, smtp_code, 3);
4300 s = string_catn(s, &size, &ptr, US"-STARTTLS\r\n", 11);
4301 tls_advertised = TRUE;
4305 #ifndef DISABLE_PRDR
4306 /* Per Recipient Data Response, draft by Eric A. Hall extending RFC */
4309 s = string_catn(s, &size, &ptr, smtp_code, 3);
4310 s = string_catn(s, &size, &ptr, US"-PRDR\r\n", 7);
4315 if ( accept_8bitmime
4316 && verify_check_host(&smtputf8_advertise_hosts) != FAIL)
4318 s = string_catn(s, &size, &ptr, smtp_code, 3);
4319 s = string_catn(s, &size, &ptr, US"-SMTPUTF8\r\n", 11);
4320 smtputf8_advertised = TRUE;
4324 /* Finish off the multiline reply with one that is always available. */
4326 s = string_catn(s, &size, &ptr, smtp_code, 3);
4327 s = string_catn(s, &size, &ptr, US" HELP\r\n", 7);
4330 /* Terminate the string (for debug), write it, and note that HELO/EHLO
4336 if (tls_in.active >= 0) (void)tls_write(TRUE, s, ptr, FALSE); else
4340 int i = fwrite(s, 1, ptr, smtp_out); i = i; /* compiler quietening */
4345 while ((cr = Ustrchr(s, '\r')) != NULL) /* lose CRs */
4346 memmove(cr, cr + 1, (ptr--) - (cr - s));
4347 debug_printf("SMTP>> %s", s);
4351 /* Reset the protocol and the state, abandoning any previous message. */
4353 (sender_host_address ? protocols : protocols_local)
4355 ? pextend + (sender_host_authenticated ? pauthed : 0)
4357 + (tls_in.active >= 0 ? pcrpted : 0)
4359 cancel_cutthrough_connection(TRUE, US"sent EHLO response");
4360 smtp_reset(reset_point);
4362 break; /* HELO/EHLO */
4365 /* The MAIL command requires an address as an operand. All we do
4366 here is to parse it for syntactic correctness. The form "<>" is
4367 a special case which converts into an empty string. The start/end
4368 pointers in the original are not used further for this address, as
4369 it is the canonical extracted address which is all that is kept. */
4373 smtp_mailcmd_count++; /* Count for limit and ratelimit */
4374 was_rej_mail = TRUE; /* Reset if accepted */
4375 env_mail_type_t * mail_args; /* Sanity check & validate args */
4377 if (helo_required && !helo_seen)
4379 smtp_printf("503 HELO or EHLO required\r\n", FALSE);
4380 log_write(0, LOG_MAIN|LOG_REJECT, "rejected MAIL from %s: no "
4381 "HELO/EHLO given", host_and_ident(FALSE));
4385 if (sender_address != NULL)
4387 done = synprot_error(L_smtp_protocol_error, 503, NULL,
4388 US"sender already given");
4392 if (smtp_cmd_data[0] == 0)
4394 done = synprot_error(L_smtp_protocol_error, 501, NULL,
4395 US"MAIL must have an address operand");
4399 /* Check to see if the limit for messages per connection would be
4400 exceeded by accepting further messages. */
4402 if (smtp_accept_max_per_connection > 0 &&
4403 smtp_mailcmd_count > smtp_accept_max_per_connection)
4405 smtp_printf("421 too many messages in this connection\r\n", FALSE);
4406 log_write(0, LOG_MAIN|LOG_REJECT, "rejected MAIL command %s: too many "
4407 "messages in one connection", host_and_ident(TRUE));
4411 /* Reset for start of message - even if this is going to fail, we
4412 obviously need to throw away any previous data. */
4414 cancel_cutthrough_connection(TRUE, US"MAIL received");
4415 smtp_reset(reset_point);
4417 sender_data = recipient_data = NULL;
4419 /* Loop, checking for ESMTP additions to the MAIL FROM command. */
4423 uschar *name, *value, *end;
4424 unsigned long int size;
4425 BOOL arg_error = FALSE;
4427 if (!extract_option(&name, &value)) break;
4429 for (mail_args = env_mail_type_list;
4430 mail_args->value != ENV_MAIL_OPT_NULL;
4433 if (strcmpic(name, mail_args->name) == 0)
4435 if (mail_args->need_value && strcmpic(value, US"") == 0)
4438 switch(mail_args->value)
4440 /* Handle SIZE= by reading the value. We don't do the check till later,
4441 in order to be able to log the sender address on failure. */
4442 case ENV_MAIL_OPT_SIZE:
4443 if (((size = Ustrtoul(value, &end, 10)), *end == 0))
4445 if ((size == ULONG_MAX && errno == ERANGE) || size > INT_MAX)
4447 message_size = (int)size;
4453 /* If this session was initiated with EHLO and accept_8bitmime is set,
4454 Exim will have indicated that it supports the BODY=8BITMIME option. In
4455 fact, it does not support this according to the RFCs, in that it does not
4456 take any special action for forwarding messages containing 8-bit
4457 characters. That is why accept_8bitmime is not the default setting, but
4458 some sites want the action that is provided. We recognize both "8BITMIME"
4459 and "7BIT" as body types, but take no action. */
4460 case ENV_MAIL_OPT_BODY:
4461 if (accept_8bitmime) {
4462 if (strcmpic(value, US"8BITMIME") == 0)
4464 else if (strcmpic(value, US"7BIT") == 0)
4469 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4470 US"invalid data for BODY");
4473 DEBUG(D_receive) debug_printf("8BITMIME: %d\n", body_8bitmime);
4479 /* Handle the two DSN options, but only if configured to do so (which
4480 will have caused "DSN" to be given in the EHLO response). The code itself
4481 is included only if configured in at build time. */
4483 case ENV_MAIL_OPT_RET:
4486 /* Check if RET has already been set */
4489 synprot_error(L_smtp_syntax_error, 501, NULL,
4490 US"RET can be specified once only");
4493 dsn_ret = strcmpic(value, US"HDRS") == 0
4495 : strcmpic(value, US"FULL") == 0
4498 DEBUG(D_receive) debug_printf("DSN_RET: %d\n", dsn_ret);
4499 /* Check for invalid invalid value, and exit with error */
4502 synprot_error(L_smtp_syntax_error, 501, NULL,
4503 US"Value for RET is invalid");
4508 case ENV_MAIL_OPT_ENVID:
4511 /* Check if the dsn envid has been already set */
4512 if (dsn_envid != NULL)
4514 synprot_error(L_smtp_syntax_error, 501, NULL,
4515 US"ENVID can be specified once only");
4518 dsn_envid = string_copy(value);
4519 DEBUG(D_receive) debug_printf("DSN_ENVID: %s\n", dsn_envid);
4523 /* Handle the AUTH extension. If the value given is not "<>" and either
4524 the ACL says "yes" or there is no ACL but the sending host is
4525 authenticated, we set it up as the authenticated sender. However, if the
4526 authenticator set a condition to be tested, we ignore AUTH on MAIL unless
4527 the condition is met. The value of AUTH is an xtext, which means that +,
4528 = and cntrl chars are coded in hex; however "<>" is unaffected by this
4530 case ENV_MAIL_OPT_AUTH:
4531 if (Ustrcmp(value, "<>") != 0)
4536 if (auth_xtextdecode(value, &authenticated_sender) < 0)
4538 /* Put back terminator overrides for error message */
4541 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4542 US"invalid data for AUTH");
4545 if (acl_smtp_mailauth == NULL)
4547 ignore_msg = US"client not authenticated";
4548 rc = (sender_host_authenticated != NULL)? OK : FAIL;
4552 ignore_msg = US"rejected by ACL";
4553 rc = acl_check(ACL_WHERE_MAILAUTH, NULL, acl_smtp_mailauth,
4554 &user_msg, &log_msg);
4560 if (authenticated_by == NULL ||
4561 authenticated_by->mail_auth_condition == NULL ||
4562 expand_check_condition(authenticated_by->mail_auth_condition,
4563 authenticated_by->name, US"authenticator"))
4564 break; /* Accept the AUTH */
4566 ignore_msg = US"server_mail_auth_condition failed";
4567 if (authenticated_id != NULL)
4568 ignore_msg = string_sprintf("%s: authenticated ID=\"%s\"",
4569 ignore_msg, authenticated_id);
4574 authenticated_sender = NULL;
4575 log_write(0, LOG_MAIN, "ignoring AUTH=%s from %s (%s)",
4576 value, host_and_ident(TRUE), ignore_msg);
4579 /* Should only get DEFER or ERROR here. Put back terminator
4580 overrides for error message */
4585 (void)smtp_handle_acl_fail(ACL_WHERE_MAILAUTH, rc, user_msg,
4592 #ifndef DISABLE_PRDR
4593 case ENV_MAIL_OPT_PRDR:
4595 prdr_requested = TRUE;
4600 case ENV_MAIL_OPT_UTF8:
4601 if (smtputf8_advertised)
4603 int old_pool = store_pool;
4605 DEBUG(D_receive) debug_printf("smtputf8 requested\n");
4606 message_smtputf8 = allow_utf8_domains = TRUE;
4607 store_pool = POOL_PERM;
4608 received_protocol = string_sprintf("utf8%s", received_protocol);
4609 store_pool = old_pool;
4613 /* No valid option. Stick back the terminator characters and break
4614 the loop. Do the name-terminator second as extract_option sets
4615 value==name when it found no equal-sign.
4616 An error for a malformed address will occur. */
4617 case ENV_MAIL_OPT_NULL:
4625 /* Break out of for loop if switch() had bad argument or
4626 when start of the email address is reached */
4627 if (arg_error) break;
4630 /* If we have passed the threshold for rate limiting, apply the current
4631 delay, and update it for next time, provided this is a limited host. */
4633 if (smtp_mailcmd_count > smtp_rlm_threshold &&
4634 verify_check_host(&smtp_ratelimit_hosts) == OK)
4636 DEBUG(D_receive) debug_printf("rate limit MAIL: delay %.3g sec\n",
4637 smtp_delay_mail/1000.0);
4638 millisleep((int)smtp_delay_mail);
4639 smtp_delay_mail *= smtp_rlm_factor;
4640 if (smtp_delay_mail > (double)smtp_rlm_limit)
4641 smtp_delay_mail = (double)smtp_rlm_limit;
4644 /* Now extract the address, first applying any SMTP-time rewriting. The
4645 TRUE flag allows "<>" as a sender address. */
4647 raw_sender = rewrite_existflags & rewrite_smtp
4648 ? rewrite_one(smtp_cmd_data, rewrite_smtp, NULL, FALSE, US"",
4649 global_rewrite_rules)
4653 parse_extract_address(raw_sender, &errmess, &start, &end, &sender_domain,
4658 done = synprot_error(L_smtp_syntax_error, 501, smtp_cmd_data, errmess);
4662 sender_address = raw_sender;
4664 /* If there is a configured size limit for mail, check that this message
4665 doesn't exceed it. The check is postponed to this point so that the sender
4668 if (thismessage_size_limit > 0 && message_size > thismessage_size_limit)
4670 smtp_printf("552 Message size exceeds maximum permitted\r\n", FALSE);
4671 log_write(L_size_reject,
4672 LOG_MAIN|LOG_REJECT, "rejected MAIL FROM:<%s> %s: "
4673 "message too big: size%s=%d max=%d",
4675 host_and_ident(TRUE),
4676 (message_size == INT_MAX)? ">" : "",
4678 thismessage_size_limit);
4679 sender_address = NULL;
4683 /* Check there is enough space on the disk unless configured not to.
4684 When smtp_check_spool_space is set, the check is for thismessage_size_limit
4685 plus the current message - i.e. we accept the message only if it won't
4686 reduce the space below the threshold. Add 5000 to the size to allow for
4687 overheads such as the Received: line and storing of recipients, etc.
4688 By putting the check here, even when SIZE is not given, it allow VRFY
4689 and EXPN etc. to be used when space is short. */
4691 if (!receive_check_fs(
4692 (smtp_check_spool_space && message_size >= 0)?
4693 message_size + 5000 : 0))
4695 smtp_printf("452 Space shortage, please try later\r\n", FALSE);
4696 sender_address = NULL;
4700 /* If sender_address is unqualified, reject it, unless this is a locally
4701 generated message, or the sending host or net is permitted to send
4702 unqualified addresses - typically local machines behaving as MUAs -
4703 in which case just qualify the address. The flag is set above at the start
4704 of the SMTP connection. */
4706 if (sender_domain == 0 && sender_address[0] != 0)
4708 if (allow_unqualified_sender)
4710 sender_domain = Ustrlen(sender_address) + 1;
4711 sender_address = rewrite_address_qualify(sender_address, FALSE);
4712 DEBUG(D_receive) debug_printf("unqualified address %s accepted\n",
4717 smtp_printf("501 %s: sender address must contain a domain\r\n", FALSE,
4719 log_write(L_smtp_syntax_error,
4720 LOG_MAIN|LOG_REJECT,
4721 "unqualified sender rejected: <%s> %s%s",
4723 host_and_ident(TRUE),
4725 sender_address = NULL;
4730 /* Apply an ACL check if one is defined, before responding. Afterwards,
4731 when pipelining is not advertised, do another sync check in case the ACL
4732 delayed and the client started sending in the meantime. */
4736 rc = acl_check(ACL_WHERE_MAIL, NULL, acl_smtp_mail, &user_msg, &log_msg);
4737 if (rc == OK && !pipelining_advertised && !check_sync())
4743 if (rc == OK || rc == DISCARD)
4745 BOOL more = pipeline_response();
4748 smtp_printf("%s%s%s", more, US"250 OK",
4749 #ifndef DISABLE_PRDR
4750 prdr_requested ? US", PRDR Requested" : US"",
4757 #ifndef DISABLE_PRDR
4759 user_msg = string_sprintf("%s%s", user_msg, US", PRDR Requested");
4761 smtp_user_msg(US"250", user_msg);
4763 smtp_delay_rcpt = smtp_rlr_base;
4764 recipients_discarded = (rc == DISCARD);
4765 was_rej_mail = FALSE;
4769 done = smtp_handle_acl_fail(ACL_WHERE_MAIL, rc, user_msg, log_msg);
4770 sender_address = NULL;
4775 /* The RCPT command requires an address as an operand. There may be any
4776 number of RCPT commands, specifying multiple recipients. We build them all
4777 into a data structure. The start/end values given by parse_extract_address
4778 are not used, as we keep only the extracted address. */
4783 was_rcpt = rcpt_in_progress = TRUE;
4785 /* There must be a sender address; if the sender was rejected and
4786 pipelining was advertised, we assume the client was pipelining, and do not
4787 count this as a protocol error. Reset was_rej_mail so that further RCPTs
4788 get the same treatment. */
4790 if (sender_address == NULL)
4792 if (pipelining_advertised && last_was_rej_mail)
4794 smtp_printf("503 sender not yet given\r\n", FALSE);
4795 was_rej_mail = TRUE;
4799 done = synprot_error(L_smtp_protocol_error, 503, NULL,
4800 US"sender not yet given");
4801 was_rcpt = FALSE; /* Not a valid RCPT */
4807 /* Check for an operand */
4809 if (smtp_cmd_data[0] == 0)
4811 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4812 US"RCPT must have an address operand");
4817 /* Set the DSN flags orcpt and dsn_flags from the session*/
4823 uschar *name, *value;
4825 if (!extract_option(&name, &value))
4828 if (dsn_advertised && strcmpic(name, US"ORCPT") == 0)
4830 /* Check whether orcpt has been already set */
4833 synprot_error(L_smtp_syntax_error, 501, NULL,
4834 US"ORCPT can be specified once only");
4837 orcpt = string_copy(value);
4838 DEBUG(D_receive) debug_printf("DSN orcpt: %s\n", orcpt);
4841 else if (dsn_advertised && strcmpic(name, US"NOTIFY") == 0)
4843 /* Check if the notify flags have been already set */
4846 synprot_error(L_smtp_syntax_error, 501, NULL,
4847 US"NOTIFY can be specified once only");
4850 if (strcmpic(value, US"NEVER") == 0)
4851 flags |= rf_notify_never;
4858 while (*pp != 0 && *pp != ',') pp++;
4859 if (*pp == ',') *pp++ = 0;
4860 if (strcmpic(p, US"SUCCESS") == 0)
4862 DEBUG(D_receive) debug_printf("DSN: Setting notify success\n");
4863 flags |= rf_notify_success;
4865 else if (strcmpic(p, US"FAILURE") == 0)
4867 DEBUG(D_receive) debug_printf("DSN: Setting notify failure\n");
4868 flags |= rf_notify_failure;
4870 else if (strcmpic(p, US"DELAY") == 0)
4872 DEBUG(D_receive) debug_printf("DSN: Setting notify delay\n");
4873 flags |= rf_notify_delay;
4877 /* Catch any strange values */
4878 synprot_error(L_smtp_syntax_error, 501, NULL,
4879 US"Invalid value for NOTIFY parameter");
4884 DEBUG(D_receive) debug_printf("DSN Flags: %x\n", flags);
4888 /* Unknown option. Stick back the terminator characters and break
4889 the loop. An error for a malformed address will occur. */
4893 DEBUG(D_receive) debug_printf("Invalid RCPT option: %s : %s\n", name, value);
4900 /* Apply SMTP rewriting then extract the working address. Don't allow "<>"
4901 as a recipient address */
4903 recipient = rewrite_existflags & rewrite_smtp
4904 ? rewrite_one(smtp_cmd_data, rewrite_smtp, NULL, FALSE, US"",
4905 global_rewrite_rules)
4908 if (!(recipient = parse_extract_address(recipient, &errmess, &start, &end,
4909 &recipient_domain, FALSE)))
4911 done = synprot_error(L_smtp_syntax_error, 501, smtp_cmd_data, errmess);
4916 /* If the recipient address is unqualified, reject it, unless this is a
4917 locally generated message. However, unqualified addresses are permitted
4918 from a configured list of hosts and nets - typically when behaving as
4919 MUAs rather than MTAs. Sad that SMTP is used for both types of traffic,
4920 really. The flag is set at the start of the SMTP connection.
4922 RFC 1123 talks about supporting "the reserved mailbox postmaster"; I always
4923 assumed this meant "reserved local part", but the revision of RFC 821 and
4924 friends now makes it absolutely clear that it means *mailbox*. Consequently
4925 we must always qualify this address, regardless. */
4927 if (!recipient_domain)
4928 if (!(recipient_domain = qualify_recipient(&recipient, smtp_cmd_data,
4935 /* Check maximum allowed */
4937 if (rcpt_count > recipients_max && recipients_max > 0)
4939 if (recipients_max_reject)
4942 smtp_printf("552 too many recipients\r\n", FALSE);
4944 log_write(0, LOG_MAIN|LOG_REJECT, "too many recipients: message "
4945 "rejected: sender=<%s> %s", sender_address, host_and_ident(TRUE));
4950 smtp_printf("452 too many recipients\r\n", FALSE);
4952 log_write(0, LOG_MAIN|LOG_REJECT, "too many recipients: excess "
4953 "temporarily rejected: sender=<%s> %s", sender_address,
4954 host_and_ident(TRUE));
4961 /* If we have passed the threshold for rate limiting, apply the current
4962 delay, and update it for next time, provided this is a limited host. */
4964 if (rcpt_count > smtp_rlr_threshold &&
4965 verify_check_host(&smtp_ratelimit_hosts) == OK)
4967 DEBUG(D_receive) debug_printf("rate limit RCPT: delay %.3g sec\n",
4968 smtp_delay_rcpt/1000.0);
4969 millisleep((int)smtp_delay_rcpt);
4970 smtp_delay_rcpt *= smtp_rlr_factor;
4971 if (smtp_delay_rcpt > (double)smtp_rlr_limit)
4972 smtp_delay_rcpt = (double)smtp_rlr_limit;
4975 /* If the MAIL ACL discarded all the recipients, we bypass ACL checking
4976 for them. Otherwise, check the access control list for this recipient. As
4977 there may be a delay in this, re-check for a synchronization error
4978 afterwards, unless pipelining was advertised. */
4980 if (recipients_discarded)
4983 if ( (rc = acl_check(ACL_WHERE_RCPT, recipient, acl_smtp_rcpt, &user_msg,
4985 && !pipelining_advertised && !check_sync())
4988 /* The ACL was happy */
4992 BOOL more = pipeline_response();
4995 smtp_user_msg(US"250", user_msg);
4997 smtp_printf("250 Accepted\r\n", more);
4998 receive_add_recipient(recipient, -1);
5000 /* Set the dsn flags in the recipients_list */
5001 recipients_list[recipients_count-1].orcpt = orcpt;
5002 recipients_list[recipients_count-1].dsn_flags = flags;
5004 DEBUG(D_receive) debug_printf("DSN: orcpt: %s flags: %d\n",
5005 recipients_list[recipients_count-1].orcpt,
5006 recipients_list[recipients_count-1].dsn_flags);
5009 /* The recipient was discarded */
5011 else if (rc == DISCARD)
5014 smtp_user_msg(US"250", user_msg);
5016 smtp_printf("250 Accepted\r\n", FALSE);
5019 log_write(0, LOG_MAIN|LOG_REJECT, "%s F=<%s> RCPT %s: "
5020 "discarded by %s ACL%s%s", host_and_ident(TRUE),
5021 sender_address_unrewritten? sender_address_unrewritten : sender_address,
5022 smtp_cmd_argument, recipients_discarded? "MAIL" : "RCPT",
5023 log_msg ? US": " : US"", log_msg ? log_msg : US"");
5026 /* Either the ACL failed the address, or it was deferred. */
5030 if (rc == FAIL) rcpt_fail_count++; else rcpt_defer_count++;
5031 done = smtp_handle_acl_fail(ACL_WHERE_RCPT, rc, user_msg, log_msg);
5036 /* The DATA command is legal only if it follows successful MAIL FROM
5037 and RCPT TO commands. However, if pipelining is advertised, a bad DATA is
5038 not counted as a protocol error if it follows RCPT (which must have been
5039 rejected if there are no recipients.) This function is complete when a
5040 valid DATA command is encountered.
5042 Note concerning the code used: RFC 2821 says this:
5044 - If there was no MAIL, or no RCPT, command, or all such commands
5045 were rejected, the server MAY return a "command out of sequence"
5046 (503) or "no valid recipients" (554) reply in response to the
5049 The example in the pipelining RFC 2920 uses 554, but I use 503 here
5050 because it is the same whether pipelining is in use or not.
5052 If all the RCPT commands that precede DATA provoked the same error message
5053 (often indicating some kind of system error), it is helpful to include it
5054 with the DATA rejection (an idea suggested by Tony Finch). */
5061 if (chunking_state != CHUNKING_OFFERED)
5063 done = synprot_error(L_smtp_protocol_error, 503, NULL,
5064 US"BDAT command used when CHUNKING not advertised");
5068 /* grab size, endmarker */
5070 if (sscanf(CS smtp_cmd_data, "%u %n", &chunking_datasize, &n) < 1)
5072 done = synprot_error(L_smtp_protocol_error, 501, NULL,
5073 US"missing size for BDAT command");
5076 chunking_state = strcmpic(smtp_cmd_data+n, US"LAST") == 0
5077 ? CHUNKING_LAST : CHUNKING_ACTIVE;
5078 chunking_data_left = chunking_datasize;
5079 DEBUG(D_receive) debug_printf("chunking state %d, %d bytes\n",
5080 (int)chunking_state, chunking_data_left);
5082 lwr_receive_getc = receive_getc;
5083 lwr_receive_getbuf = receive_getbuf;
5084 lwr_receive_ungetc = receive_ungetc;
5085 receive_getc = bdat_getc;
5086 receive_ungetc = bdat_ungetc;
5094 DATA_BDAT: /* Common code for DATA and BDAT */
5095 if (!discarded && recipients_count <= 0)
5097 if (rcpt_smtp_response_same && rcpt_smtp_response != NULL)
5099 uschar *code = US"503";
5100 int len = Ustrlen(rcpt_smtp_response);
5101 smtp_respond(code, 3, FALSE, US"All RCPT commands were rejected with "
5103 /* Responses from smtp_printf() will have \r\n on the end */
5104 if (len > 2 && rcpt_smtp_response[len-2] == '\r')
5105 rcpt_smtp_response[len-2] = 0;
5106 smtp_respond(code, 3, FALSE, rcpt_smtp_response);
5108 if (pipelining_advertised && last_was_rcpt)
5109 smtp_printf("503 Valid RCPT command must precede %s\r\n", FALSE,
5110 smtp_names[smtp_connection_had[smtp_ch_index-1]]);
5112 done = synprot_error(L_smtp_protocol_error, 503, NULL,
5113 smtp_connection_had[smtp_ch_index-1] == SCH_DATA
5114 ? US"valid RCPT command must precede DATA"
5115 : US"valid RCPT command must precede BDAT");
5117 if (chunking_state > CHUNKING_OFFERED)
5122 if (toomany && recipients_max_reject)
5124 sender_address = NULL; /* This will allow a new MAIL without RSET */
5125 sender_address_unrewritten = NULL;
5126 smtp_printf("554 Too many recipients\r\n", FALSE);
5130 if (chunking_state > CHUNKING_OFFERED)
5131 rc = OK; /* No predata ACL or go-ahead output for BDAT */
5134 /* If there is an ACL, re-check the synchronization afterwards, since the
5135 ACL may have delayed. To handle cutthrough delivery enforce a dummy call
5136 to get the DATA command sent. */
5138 if (acl_smtp_predata == NULL && cutthrough.fd < 0)
5142 uschar * acl = acl_smtp_predata ? acl_smtp_predata : US"accept";
5143 enable_dollar_recipients = TRUE;
5144 rc = acl_check(ACL_WHERE_PREDATA, NULL, acl, &user_msg,
5146 enable_dollar_recipients = FALSE;
5147 if (rc == OK && !check_sync())
5151 { /* Either the ACL failed the address, or it was deferred. */
5152 done = smtp_handle_acl_fail(ACL_WHERE_PREDATA, rc, user_msg, log_msg);
5158 smtp_user_msg(US"354", user_msg);
5161 "354 Enter message, ending with \".\" on a line by itself\r\n", FALSE);
5165 if (smtp_in) /* all ACKs needed to ramp window up for bulk data */
5166 (void) setsockopt(fileno(smtp_in), IPPROTO_TCP, TCP_QUICKACK,
5167 US &on, sizeof(on));
5170 message_ended = END_NOTENDED; /* Indicate in middle of data */
5181 if (!(address = parse_extract_address(smtp_cmd_data, &errmess,
5182 &start, &end, &recipient_domain, FALSE)))
5184 smtp_printf("501 %s\r\n", FALSE, errmess);
5188 if (!recipient_domain)
5189 if (!(recipient_domain = qualify_recipient(&address, smtp_cmd_data,
5193 if ((rc = acl_check(ACL_WHERE_VRFY, address, acl_smtp_vrfy,
5194 &user_msg, &log_msg)) != OK)
5195 done = smtp_handle_acl_fail(ACL_WHERE_VRFY, rc, user_msg, log_msg);
5199 address_item * addr = deliver_make_addr(address, FALSE);
5201 switch(verify_address(addr, NULL, vopt_is_recipient | vopt_qualify, -1,
5202 -1, -1, NULL, NULL, NULL))
5205 s = string_sprintf("250 <%s> is deliverable", address);
5209 s = (addr->user_message != NULL)?
5210 string_sprintf("451 <%s> %s", address, addr->user_message) :
5211 string_sprintf("451 Cannot resolve <%s> at this time", address);
5215 s = (addr->user_message != NULL)?
5216 string_sprintf("550 <%s> %s", address, addr->user_message) :
5217 string_sprintf("550 <%s> is not deliverable", address);
5218 log_write(0, LOG_MAIN, "VRFY failed for %s %s",
5219 smtp_cmd_argument, host_and_ident(TRUE));
5223 smtp_printf("%s\r\n", FALSE, s);
5231 rc = acl_check(ACL_WHERE_EXPN, NULL, acl_smtp_expn, &user_msg, &log_msg);
5233 done = smtp_handle_acl_fail(ACL_WHERE_EXPN, rc, user_msg, log_msg);
5236 BOOL save_log_testing_mode = log_testing_mode;
5237 address_test_mode = log_testing_mode = TRUE;
5238 (void) verify_address(deliver_make_addr(smtp_cmd_data, FALSE),
5239 smtp_out, vopt_is_recipient | vopt_qualify | vopt_expn, -1, -1, -1,
5241 address_test_mode = FALSE;
5242 log_testing_mode = save_log_testing_mode; /* true for -bh */
5251 if (!tls_advertised)
5253 done = synprot_error(L_smtp_protocol_error, 503, NULL,
5254 US"STARTTLS command used when not advertised");
5258 /* Apply an ACL check if one is defined */
5260 if ( acl_smtp_starttls
5261 && (rc = acl_check(ACL_WHERE_STARTTLS, NULL, acl_smtp_starttls,
5262 &user_msg, &log_msg)) != OK
5265 done = smtp_handle_acl_fail(ACL_WHERE_STARTTLS, rc, user_msg, log_msg);
5269 /* RFC 2487 is not clear on when this command may be sent, though it
5270 does state that all information previously obtained from the client
5271 must be discarded if a TLS session is started. It seems reasonable to
5272 do an implied RSET when STARTTLS is received. */
5274 incomplete_transaction_log(US"STARTTLS");
5275 cancel_cutthrough_connection(TRUE, US"STARTTLS received");
5276 smtp_reset(reset_point);
5278 cmd_list[CMD_LIST_STARTTLS].is_mail_cmd = FALSE;
5280 /* There's an attack where more data is read in past the STARTTLS command
5281 before TLS is negotiated, then assumed to be part of the secure session
5282 when used afterwards; we use segregated input buffers, so are not
5283 vulnerable, but we want to note when it happens and, for sheer paranoia,
5284 ensure that the buffer is "wiped".
5285 Pipelining sync checks will normally have protected us too, unless disabled
5286 by configuration. */
5288 if (receive_smtp_buffered())
5291 debug_printf("Non-empty input buffer after STARTTLS; naive attack?\n");
5292 if (tls_in.active < 0)
5293 smtp_inend = smtp_inptr = smtp_inbuffer;
5294 /* and if TLS is already active, tls_server_start() should fail */
5297 /* There is nothing we value in the input buffer and if TLS is successfully
5298 negotiated, we won't use this buffer again; if TLS fails, we'll just read
5299 fresh content into it. The buffer contains arbitrary content from an
5300 untrusted remote source; eg: NOOP <shellcode>\r\nSTARTTLS\r\n
5301 It seems safest to just wipe away the content rather than leave it as a
5302 target to jump to. */
5304 memset(smtp_inbuffer, 0, IN_BUFFER_SIZE);
5306 /* Attempt to start up a TLS session, and if successful, discard all
5307 knowledge that was obtained previously. At least, that's what the RFC says,
5308 and that's what happens by default. However, in order to work round YAEB,
5309 there is an option to remember the esmtp state. Sigh.
5311 We must allow for an extra EHLO command and an extra AUTH command after
5312 STARTTLS that don't add to the nonmail command count. */
5315 if ((rc = tls_server_start(tls_require_ciphers, &s)) == OK)
5317 if (!tls_remember_esmtp)
5318 helo_seen = esmtp = auth_advertised = pipelining_advertised = FALSE;
5319 cmd_list[CMD_LIST_EHLO].is_mail_cmd = TRUE;
5320 cmd_list[CMD_LIST_AUTH].is_mail_cmd = TRUE;
5321 cmd_list[CMD_LIST_TLS_AUTH].is_mail_cmd = TRUE;
5322 if (sender_helo_name != NULL)
5324 store_free(sender_helo_name);
5325 sender_helo_name = NULL;
5326 host_build_sender_fullhost(); /* Rebuild */
5327 set_process_info("handling incoming TLS connection from %s",
5328 host_and_ident(FALSE));
5331 (sender_host_address ? protocols : protocols_local)
5333 ? pextend + (sender_host_authenticated ? pauthed : 0)
5335 + (tls_in.active >= 0 ? pcrpted : 0)
5338 sender_host_authenticated = NULL;
5339 authenticated_id = NULL;
5340 sync_cmd_limit = NON_SYNC_CMD_NON_PIPELINING;
5341 DEBUG(D_tls) debug_printf("TLS active\n");
5342 break; /* Successful STARTTLS */
5345 (void) smtp_log_tls_fail(s);
5347 /* Some local configuration problem was discovered before actually trying
5348 to do a TLS handshake; give a temporary error. */
5352 smtp_printf("454 TLS currently unavailable\r\n", FALSE);
5356 /* Hard failure. Reject everything except QUIT or closed connection. One
5357 cause for failure is a nested STARTTLS, in which case tls_in.active remains
5358 set, but we must still reject all incoming commands. */
5360 DEBUG(D_tls) debug_printf("TLS failed to start\n");
5361 while (done <= 0) switch(smtp_read_command(FALSE, GETC_BUFFER_UNLIMITED))
5364 log_write(L_smtp_connection, LOG_MAIN, "%s closed by EOF",
5365 smtp_get_connection_info());
5366 smtp_notquit_exit(US"tls-failed", NULL, NULL);
5370 /* It is perhaps arguable as to which exit ACL should be called here,
5371 but as it is probably a situation that almost never arises, it
5372 probably doesn't matter. We choose to call the real QUIT ACL, which in
5373 some sense is perhaps "right". */
5378 && ((rc = acl_check(ACL_WHERE_QUIT, NULL, acl_smtp_quit, &user_msg,
5379 &log_msg)) == ERROR))
5380 log_write(0, LOG_MAIN|LOG_PANIC, "ACL for QUIT returned ERROR: %s",
5383 smtp_respond(US"221", 3, TRUE, user_msg);
5385 smtp_printf("221 %s closing connection\r\n", FALSE, smtp_active_hostname);
5386 log_write(L_smtp_connection, LOG_MAIN, "%s closed by QUIT",
5387 smtp_get_connection_info());
5392 smtp_printf("554 Security failure\r\n", FALSE);
5395 tls_close(TRUE, TRUE);
5400 /* The ACL for QUIT is provided for gathering statistical information or
5401 similar; it does not affect the response code, but it can supply a custom
5405 smtp_quit_handler(&user_msg, &log_msg);
5411 smtp_rset_handler();
5412 cancel_cutthrough_connection(TRUE, US"RSET received");
5413 smtp_reset(reset_point);
5420 smtp_printf("250 OK\r\n", FALSE);
5424 /* Show ETRN/EXPN/VRFY if there's an ACL for checking hosts; if actually
5425 used, a check will be done for permitted hosts. Show STARTTLS only if not
5426 already in a TLS session and if it would be advertised in the EHLO
5431 smtp_printf("214-Commands supported:\r\n", TRUE);
5435 Ustrcat(buffer, " AUTH");
5437 if (tls_in.active < 0 &&
5438 verify_check_host(&tls_advertise_hosts) != FAIL)
5439 Ustrcat(buffer, " STARTTLS");
5441 Ustrcat(buffer, " HELO EHLO MAIL RCPT DATA BDAT");
5442 Ustrcat(buffer, " NOOP QUIT RSET HELP");
5443 if (acl_smtp_etrn != NULL) Ustrcat(buffer, " ETRN");
5444 if (acl_smtp_expn != NULL) Ustrcat(buffer, " EXPN");
5445 if (acl_smtp_vrfy != NULL) Ustrcat(buffer, " VRFY");
5446 smtp_printf("214%s\r\n", FALSE, buffer);
5452 incomplete_transaction_log(US"connection lost");
5453 smtp_notquit_exit(US"connection-lost", US"421",
5454 US"%s lost input connection", smtp_active_hostname);
5456 /* Don't log by default unless in the middle of a message, as some mailers
5457 just drop the call rather than sending QUIT, and it clutters up the logs.
5460 if (sender_address != NULL || recipients_count > 0)
5461 log_write(L_lost_incoming_connection,
5463 "unexpected %s while reading SMTP command from %s%s",
5464 sender_host_unknown? "EOF" : "disconnection",
5465 host_and_ident(FALSE), smtp_read_error);
5467 else log_write(L_smtp_connection, LOG_MAIN, "%s lost%s",
5468 smtp_get_connection_info(), smtp_read_error);
5476 if (sender_address != NULL)
5478 done = synprot_error(L_smtp_protocol_error, 503, NULL,
5479 US"ETRN is not permitted inside a transaction");
5483 log_write(L_etrn, LOG_MAIN, "ETRN %s received from %s", smtp_cmd_argument,
5484 host_and_ident(FALSE));
5486 if ((rc = acl_check(ACL_WHERE_ETRN, NULL, acl_smtp_etrn,
5487 &user_msg, &log_msg)) != OK)
5489 done = smtp_handle_acl_fail(ACL_WHERE_ETRN, rc, user_msg, log_msg);
5493 /* Compute the serialization key for this command. */
5495 etrn_serialize_key = string_sprintf("etrn-%s\n", smtp_cmd_data);
5497 /* If a command has been specified for running as a result of ETRN, we
5498 permit any argument to ETRN. If not, only the # standard form is permitted,
5499 since that is strictly the only kind of ETRN that can be implemented
5500 according to the RFC. */
5502 if (smtp_etrn_command != NULL)
5506 etrn_command = smtp_etrn_command;
5507 deliver_domain = smtp_cmd_data;
5508 rc = transport_set_up_command(&argv, smtp_etrn_command, TRUE, 0, NULL,
5509 US"ETRN processing", &error);
5510 deliver_domain = NULL;
5513 log_write(0, LOG_MAIN|LOG_PANIC, "failed to set up ETRN command: %s",
5515 smtp_printf("458 Internal failure\r\n", FALSE);
5520 /* Else set up to call Exim with the -R option. */
5524 if (*smtp_cmd_data++ != '#')
5526 done = synprot_error(L_smtp_syntax_error, 501, NULL,
5527 US"argument must begin with #");
5530 etrn_command = US"exim -R";
5531 argv = CUSS child_exec_exim(CEE_RETURN_ARGV, TRUE, NULL, TRUE,
5532 *queue_name ? 4 : 2,
5533 US"-R", smtp_cmd_data,
5534 US"-MCG", queue_name);
5537 /* If we are host-testing, don't actually do anything. */
5543 debug_printf("ETRN command is: %s\n", etrn_command);
5544 debug_printf("ETRN command execution skipped\n");
5546 if (user_msg == NULL) smtp_printf("250 OK\r\n", FALSE);
5547 else smtp_user_msg(US"250", user_msg);
5552 /* If ETRN queue runs are to be serialized, check the database to
5553 ensure one isn't already running. */
5555 if (smtp_etrn_serialize && !enq_start(etrn_serialize_key, 1))
5557 smtp_printf("458 Already processing %s\r\n", FALSE, smtp_cmd_data);
5561 /* Fork a child process and run the command. We don't want to have to
5562 wait for the process at any point, so set SIGCHLD to SIG_IGN before
5563 forking. It should be set that way anyway for external incoming SMTP,
5564 but we save and restore to be tidy. If serialization is required, we
5565 actually run the command in yet another process, so we can wait for it
5566 to complete and then remove the serialization lock. */
5568 oldsignal = signal(SIGCHLD, SIG_IGN);
5570 if ((pid = fork()) == 0)
5572 smtp_input = FALSE; /* This process is not associated with the */
5573 (void)fclose(smtp_in); /* SMTP call any more. */
5574 (void)fclose(smtp_out);
5576 signal(SIGCHLD, SIG_DFL); /* Want to catch child */
5578 /* If not serializing, do the exec right away. Otherwise, fork down
5579 into another process. */
5581 if (!smtp_etrn_serialize || (pid = fork()) == 0)
5583 DEBUG(D_exec) debug_print_argv(argv);
5584 exim_nullstd(); /* Ensure std{in,out,err} exist */
5585 execv(CS argv[0], (char *const *)argv);
5586 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "exec of \"%s\" (ETRN) failed: %s",
5587 etrn_command, strerror(errno));
5588 _exit(EXIT_FAILURE); /* paranoia */
5591 /* Obey this if smtp_serialize and the 2nd fork yielded non-zero. That
5592 is, we are in the first subprocess, after forking again. All we can do
5593 for a failing fork is to log it. Otherwise, wait for the 2nd process to
5594 complete, before removing the serialization. */
5597 log_write(0, LOG_MAIN|LOG_PANIC, "2nd fork for serialized ETRN "
5598 "failed: %s", strerror(errno));
5602 DEBUG(D_any) debug_printf("waiting for serialized ETRN process %d\n",
5604 (void)wait(&status);
5605 DEBUG(D_any) debug_printf("serialized ETRN process %d ended\n",
5609 enq_end(etrn_serialize_key);
5610 _exit(EXIT_SUCCESS);
5613 /* Back in the top level SMTP process. Check that we started a subprocess
5614 and restore the signal state. */
5618 log_write(0, LOG_MAIN|LOG_PANIC, "fork of process for ETRN failed: %s",
5620 smtp_printf("458 Unable to fork process\r\n", FALSE);
5621 if (smtp_etrn_serialize) enq_end(etrn_serialize_key);
5625 if (user_msg == NULL) smtp_printf("250 OK\r\n", FALSE);
5626 else smtp_user_msg(US"250", user_msg);
5629 signal(SIGCHLD, oldsignal);
5634 done = synprot_error(L_smtp_syntax_error, 501, NULL,
5635 US"unexpected argument data");
5639 /* This currently happens only for NULLs, but could be extended. */
5642 done = synprot_error(L_smtp_syntax_error, 0, NULL, /* Just logs */
5643 US"NULL character(s) present (shown as '?')");
5644 smtp_printf("501 NULL characters are not allowed in SMTP commands\r\n", FALSE);
5650 if (smtp_inend >= smtp_inbuffer + IN_BUFFER_SIZE)
5651 smtp_inend = smtp_inbuffer + IN_BUFFER_SIZE - 1;
5652 c = smtp_inend - smtp_inptr;
5653 if (c > 150) c = 150;
5655 incomplete_transaction_log(US"sync failure");
5656 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP protocol synchronization error "
5657 "(next input sent too soon: pipelining was%s advertised): "
5658 "rejected \"%s\" %s next input=\"%s\"",
5659 pipelining_advertised? "" : " not",
5660 smtp_cmd_buffer, host_and_ident(TRUE),
5661 string_printing(smtp_inptr));
5662 smtp_notquit_exit(US"synchronization-error", US"554",
5663 US"SMTP synchronization error");
5664 done = 1; /* Pretend eof - drops connection */
5668 case TOO_MANY_NONMAIL_CMD:
5669 s = smtp_cmd_buffer;
5670 while (*s != 0 && !isspace(*s)) s++;
5671 incomplete_transaction_log(US"too many non-mail commands");
5672 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
5673 "nonmail commands (last was \"%.*s\")", host_and_ident(FALSE),
5674 (int)(s - smtp_cmd_buffer), smtp_cmd_buffer);
5675 smtp_notquit_exit(US"bad-commands", US"554", US"Too many nonmail commands");
5676 done = 1; /* Pretend eof - drops connection */
5679 #ifdef SUPPORT_PROXY
5680 case PROXY_FAIL_IGNORE_CMD:
5681 smtp_printf("503 Command refused, required Proxy negotiation failed\r\n", FALSE);
5686 if (unknown_command_count++ >= smtp_max_unknown_commands)
5688 log_write(L_smtp_syntax_error, LOG_MAIN,
5689 "SMTP syntax error in \"%s\" %s %s",
5690 string_printing(smtp_cmd_buffer), host_and_ident(TRUE),
5691 US"unrecognized command");
5692 incomplete_transaction_log(US"unrecognized command");
5693 smtp_notquit_exit(US"bad-commands", US"500",
5694 US"Too many unrecognized commands");
5696 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
5697 "unrecognized commands (last was \"%s\")", host_and_ident(FALSE),
5698 string_printing(smtp_cmd_buffer));
5701 done = synprot_error(L_smtp_syntax_error, 500, NULL,
5702 US"unrecognized command");
5706 /* This label is used by goto's inside loops that want to break out to
5707 the end of the command-processing loop. */
5710 last_was_rej_mail = was_rej_mail; /* Remember some last commands for */
5711 last_was_rcpt = was_rcpt; /* protocol error handling */
5715 return done - 2; /* Convert yield values */
5720 /* End of smtp_in.c */