1 /*************************************************
2 * Exim - an Internet mail transport agent *
3 *************************************************/
5 /* Copyright (c) University of Cambridge 1995 - 2018 */
6 /* See the file NOTICE for conditions of use and distribution. */
8 /* Functions for handling an incoming SMTP call. */
15 /* Initialize for TCP wrappers if so configured. It appears that the macro
16 HAVE_IPV6 is used in some versions of the tcpd.h header, so we unset it before
17 including that header, and restore its value afterwards. */
19 #ifdef USE_TCP_WRAPPERS
22 #define EXIM_HAVE_IPV6
28 #define HAVE_IPV6 TRUE
31 int allow_severity = LOG_INFO;
32 int deny_severity = LOG_NOTICE;
33 uschar *tcp_wrappers_name;
37 /* Size of buffer for reading SMTP commands. We used to use 512, as defined
38 by RFC 821. However, RFC 1869 specifies that this must be increased for SMTP
39 commands that accept arguments, and this in particular applies to AUTH, where
40 the data can be quite long. More recently this value was 2048 in Exim;
41 however, RFC 4954 (circa 2007) recommends 12288 bytes to handle AUTH. Clients
42 such as Thunderbird will send an AUTH with an initial-response for GSSAPI.
43 The maximum size of a Kerberos ticket under Windows 2003 is 12000 bytes, and
44 we need room to handle large base64-encoded AUTHs for GSSAPI.
47 #define SMTP_CMD_BUFFER_SIZE 16384
49 /* Size of buffer for reading SMTP incoming packets */
51 #define IN_BUFFER_SIZE 8192
53 /* Structure for SMTP command list */
60 short int is_mail_cmd;
63 /* Codes for identifying commands. We order them so that those that come first
64 are those for which synchronization is always required. Checking this can help
68 /* These commands are required to be synchronized, i.e. to be the last in a
69 block of commands when pipelining. */
71 HELO_CMD, EHLO_CMD, DATA_CMD, /* These are listed in the pipelining */
72 VRFY_CMD, EXPN_CMD, NOOP_CMD, /* RFC as requiring synchronization */
73 ETRN_CMD, /* This by analogy with TURN from the RFC */
74 STARTTLS_CMD, /* Required by the STARTTLS RFC */
75 TLS_AUTH_CMD, /* auto-command at start of SSL */
77 /* This is a dummy to identify the non-sync commands when pipelining */
79 NON_SYNC_CMD_PIPELINING,
81 /* These commands need not be synchronized when pipelining */
83 MAIL_CMD, RCPT_CMD, RSET_CMD,
85 /* This is a dummy to identify the non-sync commands when not pipelining */
87 NON_SYNC_CMD_NON_PIPELINING,
89 /* RFC3030 section 2: "After all MAIL and RCPT responses are collected and
90 processed the message is sent using a series of BDAT commands"
91 implies that BDAT should be synchronized. However, we see Google, at least,
92 sending MAIL,RCPT,BDAT-LAST in a single packet, clearly not waiting for
93 processing of the RCPT response(s). We shall do the same, and not require
94 synch for BDAT. Worse, as the chunk may (very likely will) follow the
95 command-header in the same packet we cannot do the usual "is there any
96 follow-on data after the command line" even for non-pipeline mode.
97 So we'll need an explicit check after reading the expected chunk amount
98 when non-pipe, before sending the ACK. */
102 /* I have been unable to find a statement about the use of pipelining
103 with AUTH, so to be on the safe side it is here, though I kind of feel
104 it should be up there with the synchronized commands. */
108 /* I'm not sure about these, but I don't think they matter. */
113 PROXY_FAIL_IGNORE_CMD,
116 /* These are specials that don't correspond to actual commands */
118 EOF_CMD, OTHER_CMD, BADARG_CMD, BADCHAR_CMD, BADSYN_CMD,
119 TOO_MANY_NONMAIL_CMD };
122 /* This is a convenience macro for adding the identity of an SMTP command
123 to the circular buffer that holds a list of the last n received. */
126 smtp_connection_had[smtp_ch_index++] = n; \
127 if (smtp_ch_index >= SMTP_HBUFF_SIZE) smtp_ch_index = 0
130 /*************************************************
131 * Local static variables *
132 *************************************************/
134 static auth_instance *authenticated_by;
135 static BOOL auth_advertised;
137 static BOOL tls_advertised;
139 static BOOL dsn_advertised;
141 static BOOL helo_required = FALSE;
142 static BOOL helo_verify = FALSE;
143 static BOOL helo_seen;
144 static BOOL helo_accept_junk;
145 static BOOL count_nonmail;
146 static BOOL pipelining_advertised;
147 static BOOL rcpt_smtp_response_same;
148 static BOOL rcpt_in_progress;
149 static int nonmail_command_count;
150 static BOOL smtp_exit_function_called = 0;
152 static BOOL smtputf8_advertised;
154 static int synprot_error_count;
155 static int unknown_command_count;
156 static int sync_cmd_limit;
157 static int smtp_write_error = 0;
159 static uschar *rcpt_smtp_response;
160 static uschar *smtp_data_buffer;
161 static uschar *smtp_cmd_data;
163 /* We need to know the position of RSET, HELO, EHLO, AUTH, and STARTTLS. Their
164 final fields of all except AUTH are forced TRUE at the start of a new message
165 setup, to allow one of each between messages that is not counted as a nonmail
166 command. (In fact, only one of HELO/EHLO is not counted.) Also, we have to
167 allow a new EHLO after starting up TLS.
169 AUTH is "falsely" labelled as a mail command initially, so that it doesn't get
170 counted. However, the flag is changed when AUTH is received, so that multiple
171 failing AUTHs will eventually hit the limit. After a successful AUTH, another
172 AUTH is already forbidden. After a TLS session is started, AUTH's flag is again
173 forced TRUE, to allow for the re-authentication that can happen at that point.
175 QUIT is also "falsely" labelled as a mail command so that it doesn't up the
176 count of non-mail commands and possibly provoke an error.
178 tls_auth is a pseudo-command, never expected in input. It is activated
179 on TLS startup and looks for a tls authenticator. */
181 static smtp_cmd_list cmd_list[] = {
182 /* name len cmd has_arg is_mail_cmd */
184 { "rset", sizeof("rset")-1, RSET_CMD, FALSE, FALSE }, /* First */
185 { "helo", sizeof("helo")-1, HELO_CMD, TRUE, FALSE },
186 { "ehlo", sizeof("ehlo")-1, EHLO_CMD, TRUE, FALSE },
187 { "auth", sizeof("auth")-1, AUTH_CMD, TRUE, TRUE },
189 { "starttls", sizeof("starttls")-1, STARTTLS_CMD, FALSE, FALSE },
190 { "tls_auth", 0, TLS_AUTH_CMD, FALSE, FALSE },
193 /* If you change anything above here, also fix the definitions below. */
195 { "mail from:", sizeof("mail from:")-1, MAIL_CMD, TRUE, TRUE },
196 { "rcpt to:", sizeof("rcpt to:")-1, RCPT_CMD, TRUE, TRUE },
197 { "data", sizeof("data")-1, DATA_CMD, FALSE, TRUE },
198 { "bdat", sizeof("bdat")-1, BDAT_CMD, TRUE, TRUE },
199 { "quit", sizeof("quit")-1, QUIT_CMD, FALSE, TRUE },
200 { "noop", sizeof("noop")-1, NOOP_CMD, TRUE, FALSE },
201 { "etrn", sizeof("etrn")-1, ETRN_CMD, TRUE, FALSE },
202 { "vrfy", sizeof("vrfy")-1, VRFY_CMD, TRUE, FALSE },
203 { "expn", sizeof("expn")-1, EXPN_CMD, TRUE, FALSE },
204 { "help", sizeof("help")-1, HELP_CMD, TRUE, FALSE }
207 static smtp_cmd_list *cmd_list_end =
208 cmd_list + sizeof(cmd_list)/sizeof(smtp_cmd_list);
210 #define CMD_LIST_RSET 0
211 #define CMD_LIST_HELO 1
212 #define CMD_LIST_EHLO 2
213 #define CMD_LIST_AUTH 3
214 #define CMD_LIST_STARTTLS 4
215 #define CMD_LIST_TLS_AUTH 5
217 /* This list of names is used for performing the smtp_no_mail logging action.
218 It must be kept in step with the SCH_xxx enumerations. */
220 static uschar *smtp_names[] =
222 US"NONE", US"AUTH", US"DATA", US"BDAT", US"EHLO", US"ETRN", US"EXPN",
223 US"HELO", US"HELP", US"MAIL", US"NOOP", US"QUIT", US"RCPT", US"RSET",
224 US"STARTTLS", US"VRFY" };
226 static uschar *protocols_local[] = {
227 US"local-smtp", /* HELO */
228 US"local-smtps", /* The rare case EHLO->STARTTLS->HELO */
229 US"local-esmtp", /* EHLO */
230 US"local-esmtps", /* EHLO->STARTTLS->EHLO */
231 US"local-esmtpa", /* EHLO->AUTH */
232 US"local-esmtpsa" /* EHLO->STARTTLS->EHLO->AUTH */
234 static uschar *protocols[] = {
236 US"smtps", /* The rare case EHLO->STARTTLS->HELO */
237 US"esmtp", /* EHLO */
238 US"esmtps", /* EHLO->STARTTLS->EHLO */
239 US"esmtpa", /* EHLO->AUTH */
240 US"esmtpsa" /* EHLO->STARTTLS->EHLO->AUTH */
245 #define pcrpted 1 /* added to pextend or pnormal */
246 #define pauthed 2 /* added to pextend */
248 /* Sanity check and validate optional args to MAIL FROM: envelope */
251 ENV_MAIL_OPT_SIZE, ENV_MAIL_OPT_BODY, ENV_MAIL_OPT_AUTH,
255 ENV_MAIL_OPT_RET, ENV_MAIL_OPT_ENVID,
261 uschar * name; /* option requested during MAIL cmd */
262 int value; /* enum type */
263 BOOL need_value; /* TRUE requires value (name=value pair format)
264 FALSE is a singleton */
266 static env_mail_type_t env_mail_type_list[] = {
267 { US"SIZE", ENV_MAIL_OPT_SIZE, TRUE },
268 { US"BODY", ENV_MAIL_OPT_BODY, TRUE },
269 { US"AUTH", ENV_MAIL_OPT_AUTH, TRUE },
271 { US"PRDR", ENV_MAIL_OPT_PRDR, FALSE },
273 { US"RET", ENV_MAIL_OPT_RET, TRUE },
274 { US"ENVID", ENV_MAIL_OPT_ENVID, TRUE },
276 { US"SMTPUTF8",ENV_MAIL_OPT_UTF8, FALSE }, /* rfc6531 */
278 /* keep this the last entry */
279 { US"NULL", ENV_MAIL_OPT_NULL, FALSE },
282 /* When reading SMTP from a remote host, we have to use our own versions of the
283 C input-reading functions, in order to be able to flush the SMTP output only
284 when about to read more data from the socket. This is the only way to get
285 optimal performance when the client is using pipelining. Flushing for every
286 command causes a separate packet and reply packet each time; saving all the
287 responses up (when pipelining) combines them into one packet and one response.
289 For simplicity, these functions are used for *all* SMTP input, not only when
290 receiving over a socket. However, after setting up a secure socket (SSL), input
291 is read via the OpenSSL library, and another set of functions is used instead
294 These functions are set in the receive_getc etc. variables and called with the
295 same interface as the C functions. However, since there can only ever be
296 one incoming SMTP call, we just use a single buffer and flags. There is no need
297 to implement a complicated private FILE-like structure.*/
299 static uschar *smtp_inbuffer;
300 static uschar *smtp_inptr;
301 static uschar *smtp_inend;
302 static int smtp_had_eof;
303 static int smtp_had_error;
306 /* forward declarations */
307 static int smtp_read_command(BOOL check_sync, unsigned buffer_lim);
308 static int synprot_error(int type, int code, uschar *data, uschar *errmess);
309 static void smtp_quit_handler(uschar **, uschar **);
310 static void smtp_rset_handler(void);
312 /*************************************************
313 * Recheck synchronization *
314 *************************************************/
316 /* Synchronization checks can never be perfect because a packet may be on its
317 way but not arrived when the check is done. Normally, the checks happen when
318 commands are read: Exim ensures that there is no more input in the input buffer.
319 In normal cases, the response to the command will be fast, and there is no
322 However, for some commands an ACL is run, and that can include delays. In those
323 cases, it is useful to do another check on the input just before sending the
324 response. This also applies at the start of a connection. This function does
325 that check by means of the select() function, as long as the facility is not
326 disabled or inappropriate. A failure of select() is ignored.
328 When there is unwanted input, we read it so that it appears in the log of the
332 Returns: TRUE if all is well; FALSE if there is input pending
336 wouldblock_reading(void)
340 struct timeval tzero;
343 if (tls_in.active >= 0)
344 return !tls_could_read();
347 if (smtp_inptr < smtp_inend)
350 fd = fileno(smtp_in);
355 rc = select(fd + 1, (SELECT_ARG2_TYPE *)&fds, NULL, NULL, &tzero);
357 if (rc <= 0) return TRUE; /* Not ready to read */
358 rc = smtp_getc(GETC_BUFFER_UNLIMITED);
359 if (rc < 0) return TRUE; /* End of file or error */
362 rc = smtp_inend - smtp_inptr;
363 if (rc > 150) rc = 150;
371 if (!smtp_enforce_sync || sender_host_address == NULL || sender_host_notsocket)
374 return wouldblock_reading();
378 /* If there's input waiting (and we're doing pipelineing) then we can pipeline
379 a reponse with the one following. */
382 pipeline_response(void)
384 if ( !smtp_enforce_sync || !sender_host_address
385 || sender_host_notsocket || !pipelining_advertised)
388 return !wouldblock_reading();
393 /*************************************************
394 * Log incomplete transactions *
395 *************************************************/
397 /* This function is called after a transaction has been aborted by RSET, QUIT,
398 connection drops or other errors. It logs the envelope information received
399 so far in order to preserve address verification attempts.
401 Argument: string to indicate what aborted the transaction
406 incomplete_transaction_log(uschar *what)
408 if (sender_address == NULL || /* No transaction in progress */
409 !LOGGING(smtp_incomplete_transaction))
412 /* Build list of recipients for logging */
414 if (recipients_count > 0)
417 raw_recipients = store_get(recipients_count * sizeof(uschar *));
418 for (i = 0; i < recipients_count; i++)
419 raw_recipients[i] = recipients_list[i].address;
420 raw_recipients_count = recipients_count;
423 log_write(L_smtp_incomplete_transaction, LOG_MAIN|LOG_SENDER|LOG_RECIPIENTS,
424 "%s incomplete transaction (%s)", host_and_ident(TRUE), what);
430 /* Refill the buffer, and notify DKIM verification code.
431 Return false for error or EOF.
435 smtp_refill(unsigned lim)
438 if (!smtp_out) return FALSE;
440 if (smtp_receive_timeout > 0) alarm(smtp_receive_timeout);
442 /* Limit amount read, so non-message data is not fed to DKIM */
444 rc = read(fileno(smtp_in), smtp_inbuffer, MIN(IN_BUFFER_SIZE, lim));
449 /* Must put the error text in fixed store, because this might be during
450 header reading, where it releases unused store above the header. */
453 smtp_had_error = save_errno;
454 smtp_read_error = string_copy_malloc(
455 string_sprintf(" (error: %s)", strerror(save_errno)));
457 else smtp_had_eof = 1;
461 dkim_exim_verify_feed(smtp_inbuffer, rc);
463 smtp_inend = smtp_inbuffer + rc;
464 smtp_inptr = smtp_inbuffer;
468 /*************************************************
469 * SMTP version of getc() *
470 *************************************************/
472 /* This gets the next byte from the SMTP input buffer. If the buffer is empty,
473 it flushes the output, and refills the buffer, with a timeout. The signal
474 handler is set appropriately by the calling function. This function is not used
475 after a connection has negotiated itself into an TLS/SSL state.
477 Arguments: lim Maximum amount to read/buffer
478 Returns: the next character or EOF
482 smtp_getc(unsigned lim)
484 if (smtp_inptr >= smtp_inend)
485 if (!smtp_refill(lim))
487 return *smtp_inptr++;
491 smtp_getbuf(unsigned * len)
496 if (smtp_inptr >= smtp_inend)
497 if (!smtp_refill(*len))
498 { *len = 0; return NULL; }
500 if ((size = smtp_inend - smtp_inptr) > *len) size = *len;
511 int n = smtp_inend - smtp_inptr;
513 dkim_exim_verify_feed(smtp_inptr, n);
518 /* Get a byte from the smtp input, in CHUNKING mode. Handle ack of the
519 previous BDAT chunk and getting new ones when we run out. Uses the
520 underlying smtp_getc or tls_getc both for that and for getting the
521 (buffered) data byte. EOD signals (an expected) no further data.
522 ERR signals a protocol error, and EOF a closed input stream.
524 Called from read_bdat_smtp() in receive.c for the message body, but also
525 by the headers read loop in receive_msg(); manipulates chunking_state
526 to handle the BDAT command/response.
527 Placed here due to the correlation with the above smtp_getc(), which it wraps,
528 and also by the need to do smtp command/response handling.
530 Arguments: lim (ignored)
531 Returns: the next character or ERR, EOD or EOF
535 bdat_getc(unsigned lim)
537 uschar * user_msg = NULL;
546 if (chunking_data_left > 0)
547 return lwr_receive_getc(chunking_data_left--);
549 receive_getc = lwr_receive_getc;
550 receive_getbuf = lwr_receive_getbuf;
551 receive_ungetc = lwr_receive_ungetc;
553 dkim_save = dkim_collect_input;
554 dkim_collect_input = FALSE;
557 /* Unless PIPELINING was offered, there should be no next command
558 until after we ack that chunk */
560 if (!pipelining_advertised && !check_sync())
562 unsigned n = smtp_inend - smtp_inptr;
565 incomplete_transaction_log(US"sync failure");
566 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP protocol synchronization error "
567 "(next input sent too soon: pipelining was not advertised): "
568 "rejected \"%s\" %s next input=\"%s\"%s",
569 smtp_cmd_buffer, host_and_ident(TRUE),
570 string_printing(string_copyn(smtp_inptr, n)),
571 smtp_inend - smtp_inptr > n ? "..." : "");
572 (void) synprot_error(L_smtp_protocol_error, 554, NULL,
573 US"SMTP synchronization error");
574 goto repeat_until_rset;
577 /* If not the last, ack the received chunk. The last response is delayed
578 until after the data ACL decides on it */
580 if (chunking_state == CHUNKING_LAST)
583 dkim_exim_verify_feed(NULL, 0); /* notify EOD */
588 smtp_printf("250 %u byte chunk received\r\n", FALSE, chunking_datasize);
589 chunking_state = CHUNKING_OFFERED;
590 DEBUG(D_receive) debug_printf("chunking state %d\n", (int)chunking_state);
592 /* Expect another BDAT cmd from input. RFC 3030 says nothing about
593 QUIT, RSET or NOOP but handling them seems obvious */
596 switch(smtp_read_command(TRUE, 1))
599 (void) synprot_error(L_smtp_protocol_error, 503, NULL,
600 US"only BDAT permissible after non-LAST BDAT");
603 switch(smtp_read_command(TRUE, 1))
605 case QUIT_CMD: smtp_quit_handler(&user_msg, &log_msg); /*FALLTHROUGH */
606 case EOF_CMD: return EOF;
607 case RSET_CMD: smtp_rset_handler(); return ERR;
608 default: if (synprot_error(L_smtp_protocol_error, 503, NULL,
609 US"only RSET accepted now") > 0)
611 goto repeat_until_rset;
615 smtp_quit_handler(&user_msg, &log_msg);
626 smtp_printf("250 OK\r\n", FALSE);
633 if (sscanf(CS smtp_cmd_data, "%u %n", &chunking_datasize, &n) < 1)
635 (void) synprot_error(L_smtp_protocol_error, 501, NULL,
636 US"missing size for BDAT command");
639 chunking_state = strcmpic(smtp_cmd_data+n, US"LAST") == 0
640 ? CHUNKING_LAST : CHUNKING_ACTIVE;
641 chunking_data_left = chunking_datasize;
642 DEBUG(D_receive) debug_printf("chunking state %d, %d bytes\n",
643 (int)chunking_state, chunking_data_left);
645 if (chunking_datasize == 0)
646 if (chunking_state == CHUNKING_LAST)
650 (void) synprot_error(L_smtp_protocol_error, 504, NULL,
651 US"zero size for BDAT command");
652 goto repeat_until_rset;
655 receive_getc = bdat_getc;
656 receive_getbuf = bdat_getbuf; /* r~getbuf is never actually used */
657 receive_ungetc = bdat_ungetc;
659 dkim_collect_input = dkim_save;
661 break; /* to top of main loop */
668 bdat_getbuf(unsigned * len)
672 if (chunking_data_left <= 0)
673 { *len = 0; return NULL; }
675 if (*len > chunking_data_left) *len = chunking_data_left;
676 buf = lwr_receive_getbuf(len); /* Either smtp_getbuf or tls_getbuf */
677 chunking_data_left -= *len;
682 bdat_flush_data(void)
684 while (chunking_data_left)
686 unsigned n = chunking_data_left;
687 if (!bdat_getbuf(&n)) break;
690 receive_getc = lwr_receive_getc;
691 receive_getbuf = lwr_receive_getbuf;
692 receive_ungetc = lwr_receive_ungetc;
694 if (chunking_state != CHUNKING_LAST)
696 chunking_state = CHUNKING_OFFERED;
697 DEBUG(D_receive) debug_printf("chunking state %d\n", (int)chunking_state);
704 /*************************************************
705 * SMTP version of ungetc() *
706 *************************************************/
708 /* Puts a character back in the input buffer. Only ever
714 Returns: the character
728 chunking_data_left++;
729 return lwr_receive_ungetc(ch);
734 /*************************************************
735 * SMTP version of feof() *
736 *************************************************/
738 /* Tests for a previous EOF
741 Returns: non-zero if the eof flag is set
753 /*************************************************
754 * SMTP version of ferror() *
755 *************************************************/
757 /* Tests for a previous read error, and returns with errno
758 restored to what it was when the error was detected.
761 Returns: non-zero if the error flag is set
767 errno = smtp_had_error;
768 return smtp_had_error;
773 /*************************************************
774 * Test for characters in the SMTP buffer *
775 *************************************************/
777 /* Used at the end of a message
786 return smtp_inptr < smtp_inend;
791 /*************************************************
792 * Write formatted string to SMTP channel *
793 *************************************************/
795 /* This is a separate function so that we don't have to repeat everything for
796 TLS support or debugging. It is global so that the daemon and the
797 authentication functions can use it. It does not return any error indication,
798 because major problems such as dropped connections won't show up till an output
799 flush for non-TLS connections. The smtp_fflush() function is available for
800 checking that: for convenience, TLS output errors are remembered here so that
801 they are also picked up later by smtp_fflush().
805 more further data expected
806 ... optional arguments
812 smtp_printf(const char *format, BOOL more, ...)
817 smtp_vprintf(format, more, ap);
821 /* This is split off so that verify.c:respond_printf() can, in effect, call
822 smtp_printf(), bearing in mind that in C a vararg function can't directly
823 call another vararg function, only a function which accepts a va_list. */
826 smtp_vprintf(const char *format, BOOL more, va_list ap)
830 yield = string_vformat(big_buffer, big_buffer_size, format, ap);
834 void *reset_point = store_get(0);
835 uschar *msg_copy, *cr, *end;
836 msg_copy = string_copy(big_buffer);
837 end = msg_copy + Ustrlen(msg_copy);
838 while ((cr = Ustrchr(msg_copy, '\r')) != NULL) /* lose CRs */
839 memmove(cr, cr + 1, (end--) - cr);
840 debug_printf("SMTP>> %s", msg_copy);
841 store_reset(reset_point);
846 log_write(0, LOG_MAIN|LOG_PANIC, "string too large in smtp_printf()");
847 smtp_closedown(US"Unexpected error");
848 exim_exit(EXIT_FAILURE, NULL);
851 /* If this is the first output for a (non-batch) RCPT command, see if all RCPTs
852 have had the same. Note: this code is also present in smtp_respond(). It would
853 be tidier to have it only in one place, but when it was added, it was easier to
854 do it that way, so as not to have to mess with the code for the RCPT command,
855 which sometimes uses smtp_printf() and sometimes smtp_respond(). */
857 if (rcpt_in_progress)
859 if (rcpt_smtp_response == NULL)
860 rcpt_smtp_response = string_copy(big_buffer);
861 else if (rcpt_smtp_response_same &&
862 Ustrcmp(rcpt_smtp_response, big_buffer) != 0)
863 rcpt_smtp_response_same = FALSE;
864 rcpt_in_progress = FALSE;
867 /* Now write the string */
870 if (tls_in.active >= 0)
872 if (tls_write(TRUE, big_buffer, Ustrlen(big_buffer), more) < 0)
873 smtp_write_error = -1;
878 if (fprintf(smtp_out, "%s", big_buffer) < 0) smtp_write_error = -1;
883 /*************************************************
884 * Flush SMTP out and check for error *
885 *************************************************/
887 /* This function isn't currently used within Exim (it detects errors when it
888 tries to read the next SMTP input), but is available for use in local_scan().
889 For non-TLS connections, it flushes the output and checks for errors. For
890 TLS-connections, it checks for a previously-detected TLS write error.
893 Returns: 0 for no error; -1 after an error
899 if (tls_in.active < 0 && fflush(smtp_out) != 0) smtp_write_error = -1;
900 return smtp_write_error;
905 /*************************************************
906 * SMTP command read timeout *
907 *************************************************/
909 /* Signal handler for timing out incoming SMTP commands. This attempts to
912 Argument: signal number (SIGALRM)
917 command_timeout_handler(int sig)
919 sig = sig; /* Keep picky compilers happy */
920 log_write(L_lost_incoming_connection,
921 LOG_MAIN, "SMTP command timeout on%s connection from %s",
922 (tls_in.active >= 0)? " TLS" : "",
923 host_and_ident(FALSE));
924 if (smtp_batched_input)
925 moan_smtp_batch(NULL, "421 SMTP command timeout"); /* Does not return */
926 smtp_notquit_exit(US"command-timeout", US"421",
927 US"%s: SMTP command timeout - closing connection", smtp_active_hostname);
928 exim_exit(EXIT_FAILURE, US"receiving");
933 /*************************************************
935 *************************************************/
937 /* Signal handler for handling SIGTERM. Again, try to finish tidily.
939 Argument: signal number (SIGTERM)
944 command_sigterm_handler(int sig)
946 sig = sig; /* Keep picky compilers happy */
947 log_write(0, LOG_MAIN, "%s closed after SIGTERM", smtp_get_connection_info());
948 if (smtp_batched_input)
949 moan_smtp_batch(NULL, "421 SIGTERM received"); /* Does not return */
950 smtp_notquit_exit(US"signal-exit", US"421",
951 US"%s: Service not available - closing connection", smtp_active_hostname);
952 exim_exit(EXIT_FAILURE, US"receiving");
959 /*************************************************
960 * Restore socket timeout to previous value *
961 *************************************************/
962 /* If the previous value was successfully retrieved, restore
963 it before returning control to the non-proxy routines
965 Arguments: fd - File descriptor for input
966 get_ok - Successfully retrieved previous values
967 tvtmp - Time struct with previous values
968 vslen - Length of time struct
972 restore_socket_timeout(int fd, int get_ok, struct timeval * tvtmp, socklen_t vslen)
975 (void) setsockopt(fd, SOL_SOCKET, SO_RCVTIMEO, CS tvtmp, vslen);
978 /*************************************************
979 * Check if host is required proxy host *
980 *************************************************/
981 /* The function determines if inbound host will be a regular smtp host
982 or if it is configured that it must use Proxy Protocol. A local
990 check_proxy_protocol_host()
994 if ( sender_host_address
995 && (rc = verify_check_this_host(CUSS &hosts_proxy, NULL, NULL,
996 sender_host_address, NULL)) == OK)
999 debug_printf("Detected proxy protocol configured host\n");
1000 proxy_session = TRUE;
1002 return proxy_session;
1006 /*************************************************
1007 * Read data until newline or end of buffer *
1008 *************************************************/
1009 /* While SMTP is server-speaks-first, TLS is client-speaks-first, so we can't
1010 read an entire buffer and assume there will be nothing past a proxy protocol
1011 header. Our approach normally is to use stdio, but again that relies upon
1012 "STARTTLS\r\n" and a server response before the client starts TLS handshake, or
1013 reading _nothing_ before client TLS handshake. So we don't want to use the
1014 usual buffering reads which may read enough to block TLS starting.
1016 So unfortunately we're down to "read one byte at a time, with a syscall each,
1017 and expect a little overhead", for all proxy-opened connections which are v1,
1018 just to handle the TLS-on-connect case. Since SSL functions wrap the
1019 underlying fd, we can't assume that we can feed them any already-read content.
1021 We need to know where to read to, the max capacity, and we'll read until we
1022 get a CR and one more character. Let the caller scream if it's CR+!LF.
1024 Return the amount read.
1028 swallow_until_crlf(int fd, uschar *base, int already, int capacity)
1030 uschar *to = base + already;
1036 /* For "PROXY UNKNOWN\r\n" we, at time of writing, expect to have read
1037 up through the \r; for the _normal_ case, we haven't yet seen the \r. */
1039 cr = memchr(base, '\r', already);
1042 if ((cr - base) < already - 1)
1044 /* \r and presumed \n already within what we have; probably not
1045 actually proxy protocol, but abort cleanly. */
1048 /* \r is last character read, just need one more. */
1052 while (capacity > 0)
1054 do { ret = recv(fd, to, 1, 0); } while (ret == -1 && errno == EINTR);
1066 /* reached end without having room for a final newline, abort */
1071 /*************************************************
1072 * Setup host for proxy protocol *
1073 *************************************************/
1074 /* The function configures the connection based on a header from the
1075 inbound host to use Proxy Protocol. The specification is very exact
1076 so exit with an error if do not find the exact required pieces. This
1077 includes an incorrect number of spaces separating args.
1080 Returns: Boolean success
1084 setup_proxy_protocol_host()
1096 struct { /* TCP/UDP over IPv4, len = 12 */
1102 struct { /* TCP/UDP over IPv6, len = 36 */
1103 uint8_t src_addr[16];
1104 uint8_t dst_addr[16];
1108 struct { /* AF_UNIX sockets, len = 216 */
1109 uschar src_addr[108];
1110 uschar dst_addr[108];
1116 /* Temp variables used in PPv2 address:port parsing */
1118 char tmpip[INET_ADDRSTRLEN];
1119 struct sockaddr_in tmpaddr;
1120 char tmpip6[INET6_ADDRSTRLEN];
1121 struct sockaddr_in6 tmpaddr6;
1123 /* We can't read "all data until end" because while SMTP is
1124 server-speaks-first, the TLS handshake is client-speaks-first, so for
1125 TLS-on-connect ports the proxy protocol header will usually be immediately
1126 followed by a TLS handshake, and with N TLS libraries, we can't reliably
1127 reinject data for reading by those. So instead we first read "enough to be
1128 safely read within the header, and figure out how much more to read".
1129 For v1 we will later read to the end-of-line, for v2 we will read based upon
1132 The v2 sig is 12 octets, and another 4 gets us the length, so we know how much
1133 data is needed total. For v1, where the line looks like:
1134 PROXY TCPn L3src L3dest SrcPort DestPort \r\n
1136 However, for v1 there's also `PROXY UNKNOWN\r\n` which is only 15 octets.
1137 We seem to support that. So, if we read 14 octets then we can tell if we're
1138 v2 or v1. If we're v1, we can continue reading as normal.
1140 If we're v2, we can't slurp up the entire header. We need the length in the
1141 15th & 16th octets, then to read everything after that.
1143 So to safely handle v1 and v2, with client-sent-first supported correctly,
1144 we have to do a minimum of 3 read calls, not 1. Eww.
1147 #define PROXY_INITIAL_READ 14
1148 #define PROXY_V2_HEADER_SIZE 16
1149 #if PROXY_INITIAL_READ > PROXY_V2_HEADER_SIZE
1150 # error Code bug in sizes of data to read for proxy usage
1155 int fd = fileno(smtp_in);
1156 const char v2sig[12] = "\x0D\x0A\x0D\x0A\x00\x0D\x0A\x51\x55\x49\x54\x0A";
1157 uschar * iptype; /* To display debug info */
1159 struct timeval tvtmp;
1160 socklen_t vslen = sizeof(struct timeval);
1163 /* Save current socket timeout values */
1164 get_ok = getsockopt(fd, SOL_SOCKET, SO_RCVTIMEO, CS &tvtmp, &vslen);
1166 /* Proxy Protocol host must send header within a short time
1167 (default 3 seconds) or it's considered invalid */
1168 tv.tv_sec = PROXY_NEGOTIATION_TIMEOUT_SEC;
1169 tv.tv_usec = PROXY_NEGOTIATION_TIMEOUT_USEC;
1170 if (setsockopt(fd, SOL_SOCKET, SO_RCVTIMEO, CS &tv, sizeof(tv)) < 0)
1175 /* The inbound host was declared to be a Proxy Protocol host, so
1176 don't do a PEEK into the data, actually slurp up enough to be
1177 "safe". Can't take it all because TLS-on-connect clients follow
1178 immediately with TLS handshake. */
1179 ret = recv(fd, &hdr, PROXY_INITIAL_READ, 0);
1181 while (ret == -1 && errno == EINTR);
1186 /* For v2, handle reading the length, and then the rest. */
1187 if ((ret == PROXY_INITIAL_READ) && (memcmp(&hdr.v2, v2sig, sizeof(v2sig)) == 0))
1192 /* First get the length fields. */
1195 retmore = recv(fd, (uschar*)&hdr + ret, PROXY_V2_HEADER_SIZE - PROXY_INITIAL_READ, 0);
1196 } while (retmore == -1 && errno == EINTR);
1201 ver = (hdr.v2.ver_cmd & 0xf0) >> 4;
1203 /* May 2014: haproxy combined the version and command into one byte to
1204 allow two full bytes for the length field in order to proxy SSL
1205 connections. SSL Proxy is not supported in this version of Exim, but
1206 must still separate values here. */
1210 DEBUG(D_receive) debug_printf("Invalid Proxy Protocol version: %d\n", ver);
1214 /* The v2 header will always be 16 bytes per the spec. */
1215 size = 16 + ntohs(hdr.v2.len);
1216 DEBUG(D_receive) debug_printf("Detected PROXYv2 header, size %d (limit %d)\n",
1217 size, (int)sizeof(hdr));
1219 /* We should now have 16 octets (PROXY_V2_HEADER_SIZE), and we know the total
1220 amount that we need. Double-check that the size is not unreasonable, then
1222 if (size > sizeof(hdr))
1224 DEBUG(D_receive) debug_printf("PROXYv2 header size unreasonably large; security attack?\n");
1232 retmore = recv(fd, (uschar*)&hdr + ret, size-ret, 0);
1233 } while (retmore == -1 && errno == EINTR);
1237 DEBUG(D_receive) debug_printf("PROXYv2: have %d/%d required octets\n", ret, size);
1238 } while (ret < size);
1240 } /* end scope for getting rest of data for v2 */
1242 /* At this point: if PROXYv2, we've read the exact size required for all data;
1243 if PROXYv1 then we've read "less than required for any valid line" and should
1246 if (ret >= 16 && memcmp(&hdr.v2, v2sig, 12) == 0)
1248 uint8_t cmd = (hdr.v2.ver_cmd & 0x0f);
1252 case 0x01: /* PROXY command */
1255 case 0x11: /* TCPv4 address type */
1257 tmpaddr.sin_addr.s_addr = hdr.v2.addr.ip4.src_addr;
1258 inet_ntop(AF_INET, &tmpaddr.sin_addr, CS &tmpip, sizeof(tmpip));
1259 if (!string_is_ip_address(US tmpip, NULL))
1261 DEBUG(D_receive) debug_printf("Invalid %s source IP\n", iptype);
1264 proxy_local_address = sender_host_address;
1265 sender_host_address = string_copy(US tmpip);
1266 tmpport = ntohs(hdr.v2.addr.ip4.src_port);
1267 proxy_local_port = sender_host_port;
1268 sender_host_port = tmpport;
1269 /* Save dest ip/port */
1270 tmpaddr.sin_addr.s_addr = hdr.v2.addr.ip4.dst_addr;
1271 inet_ntop(AF_INET, &tmpaddr.sin_addr, CS &tmpip, sizeof(tmpip));
1272 if (!string_is_ip_address(US tmpip, NULL))
1274 DEBUG(D_receive) debug_printf("Invalid %s dest port\n", iptype);
1277 proxy_external_address = string_copy(US tmpip);
1278 tmpport = ntohs(hdr.v2.addr.ip4.dst_port);
1279 proxy_external_port = tmpport;
1281 case 0x21: /* TCPv6 address type */
1283 memmove(tmpaddr6.sin6_addr.s6_addr, hdr.v2.addr.ip6.src_addr, 16);
1284 inet_ntop(AF_INET6, &tmpaddr6.sin6_addr, CS &tmpip6, sizeof(tmpip6));
1285 if (!string_is_ip_address(US tmpip6, NULL))
1287 DEBUG(D_receive) debug_printf("Invalid %s source IP\n", iptype);
1290 proxy_local_address = sender_host_address;
1291 sender_host_address = string_copy(US tmpip6);
1292 tmpport = ntohs(hdr.v2.addr.ip6.src_port);
1293 proxy_local_port = sender_host_port;
1294 sender_host_port = tmpport;
1295 /* Save dest ip/port */
1296 memmove(tmpaddr6.sin6_addr.s6_addr, hdr.v2.addr.ip6.dst_addr, 16);
1297 inet_ntop(AF_INET6, &tmpaddr6.sin6_addr, CS &tmpip6, sizeof(tmpip6));
1298 if (!string_is_ip_address(US tmpip6, NULL))
1300 DEBUG(D_receive) debug_printf("Invalid %s dest port\n", iptype);
1303 proxy_external_address = string_copy(US tmpip6);
1304 tmpport = ntohs(hdr.v2.addr.ip6.dst_port);
1305 proxy_external_port = tmpport;
1309 debug_printf("Unsupported PROXYv2 connection type: 0x%02x\n",
1313 /* Unsupported protocol, keep local connection address */
1315 case 0x00: /* LOCAL command */
1316 /* Keep local connection address for LOCAL */
1321 debug_printf("Unsupported PROXYv2 command: 0x%x\n", cmd);
1325 else if (ret >= 8 && memcmp(hdr.v1.line, "PROXY", 5) == 0)
1329 uschar *sp; /* Utility variables follow */
1334 /* get the rest of the line */
1335 r2 = swallow_until_crlf(fd, (uschar*)&hdr, ret, sizeof(hdr)-ret);
1340 p = string_copy(hdr.v1.line);
1341 end = memchr(p, '\r', ret - 1);
1343 if (!end || (end == (uschar*)&hdr + ret) || end[1] != '\n')
1345 DEBUG(D_receive) debug_printf("Partial or invalid PROXY header\n");
1348 *end = '\0'; /* Terminate the string */
1349 size = end + 2 - p; /* Skip header + CRLF */
1350 DEBUG(D_receive) debug_printf("Detected PROXYv1 header\n");
1351 DEBUG(D_receive) debug_printf("Bytes read not within PROXY header: %d\n", ret - size);
1352 /* Step through the string looking for the required fields. Ensure
1353 strict adherence to required formatting, exit for any error. */
1355 if (!isspace(*(p++)))
1357 DEBUG(D_receive) debug_printf("Missing space after PROXY command\n");
1360 if (!Ustrncmp(p, CCS"TCP4", 4))
1362 else if (!Ustrncmp(p,CCS"TCP6", 4))
1364 else if (!Ustrncmp(p,CCS"UNKNOWN", 7))
1366 iptype = US"Unknown";
1371 DEBUG(D_receive) debug_printf("Invalid TCP type\n");
1375 p += Ustrlen(iptype);
1376 if (!isspace(*(p++)))
1378 DEBUG(D_receive) debug_printf("Missing space after TCP4/6 command\n");
1381 /* Find the end of the arg */
1382 if ((sp = Ustrchr(p, ' ')) == NULL)
1385 debug_printf("Did not find proxied src %s\n", iptype);
1389 if(!string_is_ip_address(p, NULL))
1392 debug_printf("Proxied src arg is not an %s address\n", iptype);
1395 proxy_local_address = sender_host_address;
1396 sender_host_address = p;
1398 if ((sp = Ustrchr(p, ' ')) == NULL)
1401 debug_printf("Did not find proxy dest %s\n", iptype);
1405 if(!string_is_ip_address(p, NULL))
1408 debug_printf("Proxy dest arg is not an %s address\n", iptype);
1411 proxy_external_address = p;
1413 if ((sp = Ustrchr(p, ' ')) == NULL)
1415 DEBUG(D_receive) debug_printf("Did not find proxied src port\n");
1419 tmp_port = strtol(CCS p, &endc, 10);
1420 if (*endc || tmp_port == 0)
1423 debug_printf("Proxied src port '%s' not an integer\n", p);
1426 proxy_local_port = sender_host_port;
1427 sender_host_port = tmp_port;
1429 if ((sp = Ustrchr(p, '\0')) == NULL)
1431 DEBUG(D_receive) debug_printf("Did not find proxy dest port\n");
1434 tmp_port = strtol(CCS p, &endc, 10);
1435 if (*endc || tmp_port == 0)
1438 debug_printf("Proxy dest port '%s' not an integer\n", p);
1441 proxy_external_port = tmp_port;
1442 /* Already checked for /r /n above. Good V1 header received. */
1446 /* Wrong protocol */
1447 DEBUG(D_receive) debug_printf("Invalid proxy protocol version negotiation\n");
1448 (void) swallow_until_crlf(fd, (uschar*)&hdr, ret, sizeof(hdr)-ret);
1454 debug_printf("Valid %s sender from Proxy Protocol header\n", iptype);
1455 yield = proxy_session;
1457 /* Don't flush any potential buffer contents. Any input on proxyfail
1458 should cause a synchronization failure */
1461 restore_socket_timeout(fd, get_ok, &tvtmp, vslen);
1466 sender_host_name = NULL;
1467 (void) host_name_lookup();
1468 host_build_sender_fullhost();
1472 proxy_session_failed = TRUE;
1474 debug_printf("Failure to extract proxied host, only QUIT allowed\n");
1481 /*************************************************
1482 * Read one command line *
1483 *************************************************/
1485 /* Strictly, SMTP commands coming over the net are supposed to end with CRLF.
1486 There are sites that don't do this, and in any case internal SMTP probably
1487 should check only for LF. Consequently, we check here for LF only. The line
1488 ends up with [CR]LF removed from its end. If we get an overlong line, treat as
1489 an unknown command. The command is read into the global smtp_cmd_buffer so that
1490 it is available via $smtp_command.
1492 The character reading routine sets up a timeout for each block actually read
1493 from the input (which may contain more than one command). We set up a special
1494 signal handler that closes down the session on a timeout. Control does not
1495 return when it runs.
1498 check_sync if TRUE, check synchronization rules if global option is TRUE
1499 buffer_lim maximum to buffer in lower layer
1501 Returns: a code identifying the command (enumerated above)
1505 smtp_read_command(BOOL check_sync, unsigned buffer_lim)
1510 BOOL hadnull = FALSE;
1512 os_non_restarting_signal(SIGALRM, command_timeout_handler);
1514 while ((c = (receive_getc)(buffer_lim)) != '\n' && c != EOF)
1516 if (ptr >= SMTP_CMD_BUFFER_SIZE)
1518 os_non_restarting_signal(SIGALRM, sigalrm_handler);
1526 smtp_cmd_buffer[ptr++] = c;
1529 receive_linecount++; /* For BSMTP errors */
1530 os_non_restarting_signal(SIGALRM, sigalrm_handler);
1532 /* If hit end of file, return pseudo EOF command. Whether we have a
1533 part-line already read doesn't matter, since this is an error state. */
1535 if (c == EOF) return EOF_CMD;
1537 /* Remove any CR and white space at the end of the line, and terminate the
1540 while (ptr > 0 && isspace(smtp_cmd_buffer[ptr-1])) ptr--;
1541 smtp_cmd_buffer[ptr] = 0;
1543 DEBUG(D_receive) debug_printf("SMTP<< %s\n", smtp_cmd_buffer);
1545 /* NULLs are not allowed in SMTP commands */
1547 if (hadnull) return BADCHAR_CMD;
1549 /* Scan command list and return identity, having set the data pointer
1550 to the start of the actual data characters. Check for SMTP synchronization
1553 for (p = cmd_list; p < cmd_list_end; p++)
1555 #ifdef SUPPORT_PROXY
1556 /* Only allow QUIT command if Proxy Protocol parsing failed */
1557 if (proxy_session && proxy_session_failed && p->cmd != QUIT_CMD)
1561 && strncmpic(smtp_cmd_buffer, US p->name, p->len) == 0
1562 && ( smtp_cmd_buffer[p->len-1] == ':' /* "mail from:" or "rcpt to:" */
1563 || smtp_cmd_buffer[p->len] == 0
1564 || smtp_cmd_buffer[p->len] == ' '
1567 if (smtp_inptr < smtp_inend && /* Outstanding input */
1568 p->cmd < sync_cmd_limit && /* Command should sync */
1569 check_sync && /* Local flag set */
1570 smtp_enforce_sync && /* Global flag set */
1571 sender_host_address != NULL && /* Not local input */
1572 !sender_host_notsocket) /* Really is a socket */
1575 /* The variables $smtp_command and $smtp_command_argument point into the
1576 unmodified input buffer. A copy of the latter is taken for actual
1577 processing, so that it can be chopped up into separate parts if necessary,
1578 for example, when processing a MAIL command options such as SIZE that can
1579 follow the sender address. */
1581 smtp_cmd_argument = smtp_cmd_buffer + p->len;
1582 while (isspace(*smtp_cmd_argument)) smtp_cmd_argument++;
1583 Ustrcpy(smtp_data_buffer, smtp_cmd_argument);
1584 smtp_cmd_data = smtp_data_buffer;
1586 /* Count non-mail commands from those hosts that are controlled in this
1587 way. The default is all hosts. We don't waste effort checking the list
1588 until we get a non-mail command, but then cache the result to save checking
1589 again. If there's a DEFER while checking the host, assume it's in the list.
1591 Note that one instance of RSET, EHLO/HELO, and STARTTLS is allowed at the
1592 start of each incoming message by fiddling with the value in the table. */
1594 if (!p->is_mail_cmd)
1596 if (count_nonmail == TRUE_UNSET) count_nonmail =
1597 verify_check_host(&smtp_accept_max_nonmail_hosts) != FAIL;
1598 if (count_nonmail && ++nonmail_command_count > smtp_accept_max_nonmail)
1599 return TOO_MANY_NONMAIL_CMD;
1602 /* If there is data for a command that does not expect it, generate the
1605 return (p->has_arg || *smtp_cmd_data == 0)? p->cmd : BADARG_CMD;
1609 #ifdef SUPPORT_PROXY
1610 /* Only allow QUIT command if Proxy Protocol parsing failed */
1611 if (proxy_session && proxy_session_failed)
1612 return PROXY_FAIL_IGNORE_CMD;
1615 /* Enforce synchronization for unknown commands */
1617 if (smtp_inptr < smtp_inend && /* Outstanding input */
1618 check_sync && /* Local flag set */
1619 smtp_enforce_sync && /* Global flag set */
1620 sender_host_address != NULL && /* Not local input */
1621 !sender_host_notsocket) /* Really is a socket */
1629 /*************************************************
1630 * Forced closedown of call *
1631 *************************************************/
1633 /* This function is called from log.c when Exim is dying because of a serious
1634 disaster, and also from some other places. If an incoming non-batched SMTP
1635 channel is open, it swallows the rest of the incoming message if in the DATA
1636 phase, sends the reply string, and gives an error to all subsequent commands
1637 except QUIT. The existence of an SMTP call is detected by the non-NULLness of
1641 message SMTP reply string to send, excluding the code
1647 smtp_closedown(uschar *message)
1649 if (!smtp_in || smtp_batched_input) return;
1650 receive_swallow_smtp();
1651 smtp_printf("421 %s\r\n", FALSE, message);
1653 for (;;) switch(smtp_read_command(FALSE, GETC_BUFFER_UNLIMITED))
1659 smtp_printf("221 %s closing connection\r\n", FALSE, smtp_active_hostname);
1664 smtp_printf("250 Reset OK\r\n", FALSE);
1668 smtp_printf("421 %s\r\n", FALSE, message);
1676 /*************************************************
1677 * Set up connection info for logging *
1678 *************************************************/
1680 /* This function is called when logging information about an SMTP connection.
1681 It sets up appropriate source information, depending on the type of connection.
1682 If sender_fullhost is NULL, we are at a very early stage of the connection;
1683 just use the IP address.
1686 Returns: a string describing the connection
1690 smtp_get_connection_info(void)
1692 const uschar * hostname = sender_fullhost
1693 ? sender_fullhost : sender_host_address;
1696 return string_sprintf("SMTP connection from %s", hostname);
1698 if (sender_host_unknown || sender_host_notsocket)
1699 return string_sprintf("SMTP connection from %s", sender_ident);
1702 return string_sprintf("SMTP connection from %s (via inetd)", hostname);
1704 if (LOGGING(incoming_interface) && interface_address != NULL)
1705 return string_sprintf("SMTP connection from %s I=[%s]:%d", hostname,
1706 interface_address, interface_port);
1708 return string_sprintf("SMTP connection from %s", hostname);
1714 /* Append TLS-related information to a log line
1717 g String under construction: allocated string to extend, or NULL
1719 Returns: Allocated string or NULL
1722 s_tlslog(gstring * g)
1724 if (LOGGING(tls_cipher) && tls_in.cipher)
1725 g = string_append(g, 2, US" X=", tls_in.cipher);
1726 if (LOGGING(tls_certificate_verified) && tls_in.cipher)
1727 g = string_append(g, 2, US" CV=", tls_in.certificate_verified? "yes":"no");
1728 if (LOGGING(tls_peerdn) && tls_in.peerdn)
1729 g = string_append(g, 3, US" DN=\"", string_printing(tls_in.peerdn), US"\"");
1730 if (LOGGING(tls_sni) && tls_in.sni)
1731 g = string_append(g, 3, US" SNI=\"", string_printing(tls_in.sni), US"\"");
1736 /*************************************************
1737 * Log lack of MAIL if so configured *
1738 *************************************************/
1740 /* This function is called when an SMTP session ends. If the log selector
1741 smtp_no_mail is set, write a log line giving some details of what has happened
1742 in the SMTP session.
1749 smtp_log_no_mail(void)
1755 if (smtp_mailcmd_count > 0 || !LOGGING(smtp_no_mail))
1758 if (sender_host_authenticated)
1760 g = string_append(g, 2, US" A=", sender_host_authenticated);
1761 if (authenticated_id) g = string_append(g, 2, US":", authenticated_id);
1768 sep = smtp_connection_had[SMTP_HBUFF_SIZE-1] != SCH_NONE ? US" C=..." : US" C=";
1770 for (i = smtp_ch_index; i < SMTP_HBUFF_SIZE; i++)
1771 if (smtp_connection_had[i] != SCH_NONE)
1773 g = string_append(g, 2, sep, smtp_names[smtp_connection_had[i]]);
1777 for (i = 0; i < smtp_ch_index; i++)
1779 g = string_append(g, 2, sep, smtp_names[smtp_connection_had[i]]);
1783 if (!(s = string_from_gstring(g))) s = US"";
1785 log_write(0, LOG_MAIN, "no MAIL in %sSMTP connection from %s D=%s%s",
1786 tcp_in_fastopen ? US"TFO " : US"",
1787 host_and_ident(FALSE), string_timesince(&smtp_connection_start), s);
1791 /* Return list of recent smtp commands */
1797 gstring * list = NULL;
1800 for (i = smtp_ch_index; i < SMTP_HBUFF_SIZE; i++)
1801 if (smtp_connection_had[i] != SCH_NONE)
1802 list = string_append_listele(list, ',', smtp_names[smtp_connection_had[i]]);
1804 for (i = 0; i < smtp_ch_index; i++)
1805 list = string_append_listele(list, ',', smtp_names[smtp_connection_had[i]]);
1807 s = string_from_gstring(list);
1808 return s ? s : US"";
1814 /*************************************************
1815 * Check HELO line and set sender_helo_name *
1816 *************************************************/
1818 /* Check the format of a HELO line. The data for HELO/EHLO is supposed to be
1819 the domain name of the sending host, or an ip literal in square brackets. The
1820 argument is placed in sender_helo_name, which is in malloc store, because it
1821 must persist over multiple incoming messages. If helo_accept_junk is set, this
1822 host is permitted to send any old junk (needed for some broken hosts).
1823 Otherwise, helo_allow_chars can be used for rogue characters in general
1824 (typically people want to let in underscores).
1827 s the data portion of the line (already past any white space)
1829 Returns: TRUE or FALSE
1833 check_helo(uschar *s)
1836 uschar *end = s + Ustrlen(s);
1837 BOOL yield = helo_accept_junk;
1839 /* Discard any previous helo name */
1841 if (sender_helo_name)
1843 store_free(sender_helo_name);
1844 sender_helo_name = NULL;
1847 /* Skip tests if junk is permitted. */
1851 /* Allow the new standard form for IPv6 address literals, namely,
1852 [IPv6:....], and because someone is bound to use it, allow an equivalent
1853 IPv4 form. Allow plain addresses as well. */
1860 if (strncmpic(s, US"[IPv6:", 6) == 0)
1861 yield = (string_is_ip_address(s+6, NULL) == 6);
1862 else if (strncmpic(s, US"[IPv4:", 6) == 0)
1863 yield = (string_is_ip_address(s+6, NULL) == 4);
1865 yield = (string_is_ip_address(s+1, NULL) != 0);
1870 /* Non-literals must be alpha, dot, hyphen, plus any non-valid chars
1871 that have been configured (usually underscore - sigh). */
1874 for (yield = TRUE; *s; s++)
1875 if (!isalnum(*s) && *s != '.' && *s != '-' &&
1876 Ustrchr(helo_allow_chars, *s) == NULL)
1882 /* Save argument if OK */
1884 if (yield) sender_helo_name = string_copy_malloc(start);
1892 /*************************************************
1893 * Extract SMTP command option *
1894 *************************************************/
1896 /* This function picks the next option setting off the end of smtp_cmd_data. It
1897 is called for MAIL FROM and RCPT TO commands, to pick off the optional ESMTP
1898 things that can appear there.
1901 name point this at the name
1902 value point this at the data string
1904 Returns: TRUE if found an option
1908 extract_option(uschar **name, uschar **value)
1911 uschar *v = smtp_cmd_data + Ustrlen(smtp_cmd_data) - 1;
1912 while (isspace(*v)) v--;
1914 while (v > smtp_cmd_data && *v != '=' && !isspace(*v))
1916 /* Take care to not stop at a space embedded in a quoted local-part */
1918 if (*v == '"') do v--; while (*v != '"' && v > smtp_cmd_data+1);
1925 while(isalpha(n[-1])) n--;
1926 /* RFC says SP, but TAB seen in wild and other major MTAs accept it */
1927 if (!isspace(n[-1])) return FALSE;
1933 if (v == smtp_cmd_data) return FALSE;
1945 /*************************************************
1946 * Reset for new message *
1947 *************************************************/
1949 /* This function is called whenever the SMTP session is reset from
1950 within either of the setup functions; also from the daemon loop.
1952 Argument: the stacking pool storage reset point
1957 smtp_reset(void *reset_point)
1959 recipients_list = NULL;
1960 rcpt_count = rcpt_defer_count = rcpt_fail_count =
1961 raw_recipients_count = recipients_count = recipients_list_max = 0;
1962 message_linecount = 0;
1964 acl_added_headers = NULL;
1965 acl_removed_headers = NULL;
1966 queue_only_policy = FALSE;
1967 rcpt_smtp_response = NULL;
1968 rcpt_smtp_response_same = TRUE;
1969 rcpt_in_progress = FALSE;
1970 deliver_freeze = FALSE; /* Can be set by ACL */
1971 freeze_tell = freeze_tell_config; /* Can be set by ACL */
1972 fake_response = OK; /* Can be set by ACL */
1973 #ifdef WITH_CONTENT_SCAN
1974 no_mbox_unspool = FALSE; /* Can be set by ACL */
1976 submission_mode = FALSE; /* Can be set by ACL */
1977 suppress_local_fixups = suppress_local_fixups_default; /* Can be set by ACL */
1978 active_local_from_check = local_from_check; /* Can be set by ACL */
1979 active_local_sender_retain = local_sender_retain; /* Can be set by ACL */
1980 sending_ip_address = NULL;
1981 return_path = sender_address = NULL;
1982 sender_data = NULL; /* Can be set by ACL */
1983 deliver_localpart_orig = NULL;
1984 deliver_domain_orig = NULL;
1985 callout_address = NULL;
1986 submission_name = NULL; /* Can be set by ACL */
1987 raw_sender = NULL; /* After SMTP rewrite, before qualifying */
1988 sender_address_unrewritten = NULL; /* Set only after verify rewrite */
1989 sender_verified_list = NULL; /* No senders verified */
1990 memset(sender_address_cache, 0, sizeof(sender_address_cache));
1991 memset(sender_domain_cache, 0, sizeof(sender_domain_cache));
1993 authenticated_sender = NULL;
1994 #ifdef EXPERIMENTAL_BRIGHTMAIL
1996 bmi_verdicts = NULL;
1998 dnslist_domain = dnslist_matched = NULL;
1999 #ifndef DISABLE_DKIM
2000 dkim_cur_signer = dkim_signers = NULL;
2001 dkim_disable_verify = dkim_collect_input = FALSE;
2005 deliver_host = deliver_host_address = NULL; /* Can be set by ACL */
2006 #ifndef DISABLE_PRDR
2007 prdr_requested = FALSE;
2010 spf_header_comment = spf_received = spf_result = spf_smtp_comment = NULL;
2013 message_smtputf8 = FALSE;
2015 body_linecount = body_zerocount = 0;
2017 sender_rate = sender_rate_limit = sender_rate_period = NULL;
2018 ratelimiters_mail = NULL; /* Updated by ratelimit ACL condition */
2019 /* Note that ratelimiters_conn persists across resets. */
2021 /* Reset message ACL variables */
2025 /* The message body variables use malloc store. They may be set if this is
2026 not the first message in an SMTP session and the previous message caused them
2027 to be referenced in an ACL. */
2031 store_free(message_body);
2032 message_body = NULL;
2035 if (message_body_end)
2037 store_free(message_body_end);
2038 message_body_end = NULL;
2041 /* Warning log messages are also saved in malloc store. They are saved to avoid
2042 repetition in the same message, but it seems right to repeat them for different
2045 while (acl_warn_logged)
2047 string_item *this = acl_warn_logged;
2048 acl_warn_logged = acl_warn_logged->next;
2051 store_reset(reset_point);
2058 /*************************************************
2059 * Initialize for incoming batched SMTP message *
2060 *************************************************/
2062 /* This function is called from smtp_setup_msg() in the case when
2063 smtp_batched_input is true. This happens when -bS is used to pass a whole batch
2064 of messages in one file with SMTP commands between them. All errors must be
2065 reported by sending a message, and only MAIL FROM, RCPT TO, and DATA are
2066 relevant. After an error on a sender, or an invalid recipient, the remainder
2067 of the message is skipped. The value of received_protocol is already set.
2070 Returns: > 0 message successfully started (reached DATA)
2071 = 0 QUIT read or end of file reached
2072 < 0 should not occur
2076 smtp_setup_batch_msg(void)
2079 void *reset_point = store_get(0);
2081 /* Save the line count at the start of each transaction - single commands
2082 like HELO and RSET count as whole transactions. */
2084 bsmtp_transaction_linecount = receive_linecount;
2086 if ((receive_feof)()) return 0; /* Treat EOF as QUIT */
2088 cancel_cutthrough_connection(TRUE, US"smtp_setup_batch_msg");
2089 smtp_reset(reset_point); /* Reset for start of message */
2091 /* Deal with SMTP commands. This loop is exited by setting done to a POSITIVE
2092 value. The values are 2 larger than the required yield of the function. */
2097 uschar *recipient = NULL;
2098 int start, end, sender_domain, recipient_domain;
2100 switch(smtp_read_command(FALSE, GETC_BUFFER_UNLIMITED))
2102 /* The HELO/EHLO commands set sender_address_helo if they have
2103 valid data; otherwise they are ignored, except that they do
2104 a reset of the state. */
2109 check_helo(smtp_cmd_data);
2113 cancel_cutthrough_connection(TRUE, US"RSET received");
2114 smtp_reset(reset_point);
2115 bsmtp_transaction_linecount = receive_linecount;
2119 /* The MAIL FROM command requires an address as an operand. All we
2120 do here is to parse it for syntactic correctness. The form "<>" is
2121 a special case which converts into an empty string. The start/end
2122 pointers in the original are not used further for this address, as
2123 it is the canonical extracted address which is all that is kept. */
2126 smtp_mailcmd_count++; /* Count for no-mail log */
2127 if (sender_address != NULL)
2128 /* The function moan_smtp_batch() does not return. */
2129 moan_smtp_batch(smtp_cmd_buffer, "503 Sender already given");
2131 if (smtp_cmd_data[0] == 0)
2132 /* The function moan_smtp_batch() does not return. */
2133 moan_smtp_batch(smtp_cmd_buffer, "501 MAIL FROM must have an address operand");
2135 /* Reset to start of message */
2137 cancel_cutthrough_connection(TRUE, US"MAIL received");
2138 smtp_reset(reset_point);
2140 /* Apply SMTP rewrite */
2142 raw_sender = ((rewrite_existflags & rewrite_smtp) != 0)?
2143 rewrite_one(smtp_cmd_data, rewrite_smtp|rewrite_smtp_sender, NULL, FALSE,
2144 US"", global_rewrite_rules) : smtp_cmd_data;
2146 /* Extract the address; the TRUE flag allows <> as valid */
2149 parse_extract_address(raw_sender, &errmess, &start, &end, &sender_domain,
2153 /* The function moan_smtp_batch() does not return. */
2154 moan_smtp_batch(smtp_cmd_buffer, "501 %s", errmess);
2156 sender_address = string_copy(raw_sender);
2158 /* Qualify unqualified sender addresses if permitted to do so. */
2161 && sender_address[0] != 0 && sender_address[0] != '@')
2162 if (allow_unqualified_sender)
2164 sender_address = rewrite_address_qualify(sender_address, FALSE);
2165 DEBUG(D_receive) debug_printf("unqualified address %s accepted "
2166 "and rewritten\n", raw_sender);
2168 /* The function moan_smtp_batch() does not return. */
2170 moan_smtp_batch(smtp_cmd_buffer, "501 sender address must contain "
2175 /* The RCPT TO command requires an address as an operand. All we do
2176 here is to parse it for syntactic correctness. There may be any number
2177 of RCPT TO commands, specifying multiple senders. We build them all into
2178 a data structure that is in argc/argv format. The start/end values
2179 given by parse_extract_address are not used, as we keep only the
2180 extracted address. */
2183 if (!sender_address)
2184 /* The function moan_smtp_batch() does not return. */
2185 moan_smtp_batch(smtp_cmd_buffer, "503 No sender yet given");
2187 if (smtp_cmd_data[0] == 0)
2188 /* The function moan_smtp_batch() does not return. */
2189 moan_smtp_batch(smtp_cmd_buffer,
2190 "501 RCPT TO must have an address operand");
2192 /* Check maximum number allowed */
2194 if (recipients_max > 0 && recipients_count + 1 > recipients_max)
2195 /* The function moan_smtp_batch() does not return. */
2196 moan_smtp_batch(smtp_cmd_buffer, "%s too many recipients",
2197 recipients_max_reject? "552": "452");
2199 /* Apply SMTP rewrite, then extract address. Don't allow "<>" as a
2200 recipient address */
2202 recipient = rewrite_existflags & rewrite_smtp
2203 ? rewrite_one(smtp_cmd_data, rewrite_smtp, NULL, FALSE, US"",
2204 global_rewrite_rules)
2207 recipient = parse_extract_address(recipient, &errmess, &start, &end,
2208 &recipient_domain, FALSE);
2211 /* The function moan_smtp_batch() does not return. */
2212 moan_smtp_batch(smtp_cmd_buffer, "501 %s", errmess);
2214 /* If the recipient address is unqualified, qualify it if permitted. Then
2215 add it to the list of recipients. */
2217 if (!recipient_domain)
2218 if (allow_unqualified_recipient)
2220 DEBUG(D_receive) debug_printf("unqualified address %s accepted\n",
2222 recipient = rewrite_address_qualify(recipient, TRUE);
2224 /* The function moan_smtp_batch() does not return. */
2226 moan_smtp_batch(smtp_cmd_buffer,
2227 "501 recipient address must contain a domain");
2229 receive_add_recipient(recipient, -1);
2233 /* The DATA command is legal only if it follows successful MAIL FROM
2234 and RCPT TO commands. This function is complete when a valid DATA
2235 command is encountered. */
2238 if (!sender_address || recipients_count <= 0)
2239 /* The function moan_smtp_batch() does not return. */
2240 if (!sender_address)
2241 moan_smtp_batch(smtp_cmd_buffer,
2242 "503 MAIL FROM:<sender> command must precede DATA");
2244 moan_smtp_batch(smtp_cmd_buffer,
2245 "503 RCPT TO:<recipient> must precede DATA");
2248 done = 3; /* DATA successfully achieved */
2249 message_ended = END_NOTENDED; /* Indicate in middle of message */
2254 /* The VRFY, EXPN, HELP, ETRN, and NOOP commands are ignored. */
2261 bsmtp_transaction_linecount = receive_linecount;
2272 /* The function moan_smtp_batch() does not return. */
2273 moan_smtp_batch(smtp_cmd_buffer, "501 Unexpected argument data");
2278 /* The function moan_smtp_batch() does not return. */
2279 moan_smtp_batch(smtp_cmd_buffer, "501 Unexpected NULL in SMTP command");
2284 /* The function moan_smtp_batch() does not return. */
2285 moan_smtp_batch(smtp_cmd_buffer, "500 Command unrecognized");
2290 return done - 2; /* Convert yield values */
2297 smtp_log_tls_fail(uschar * errstr)
2299 uschar * conn_info = smtp_get_connection_info();
2301 if (Ustrncmp(conn_info, US"SMTP ", 5) == 0) conn_info += 5;
2302 /* I'd like to get separated H= here, but too hard for now */
2304 log_write(0, LOG_MAIN, "TLS error on %s %s", conn_info, errstr);
2316 struct tcp_info tinfo;
2317 socklen_t len = sizeof(tinfo);
2319 if ( getsockopt(fileno(smtp_out), IPPROTO_TCP, TCP_INFO, &tinfo, &len) == 0
2320 && tinfo.tcpi_state == TCP_SYN_RECV
2323 DEBUG(D_receive) debug_printf("TCP_FASTOPEN mode connection (state TCP_SYN_RECV)\n");
2324 tcp_in_fastopen = TRUE;
2331 /*************************************************
2332 * Start an SMTP session *
2333 *************************************************/
2335 /* This function is called at the start of an SMTP session. Thereafter,
2336 smtp_setup_msg() is called to initiate each separate message. This
2337 function does host-specific testing, and outputs the banner line.
2340 Returns: FALSE if the session can not continue; something has
2341 gone wrong, or the connection to the host is blocked
2345 smtp_start_session(void)
2348 uschar *user_msg, *log_msg;
2353 gettimeofday(&smtp_connection_start, NULL);
2354 for (smtp_ch_index = 0; smtp_ch_index < SMTP_HBUFF_SIZE; smtp_ch_index++)
2355 smtp_connection_had[smtp_ch_index] = SCH_NONE;
2358 /* Default values for certain variables */
2360 helo_seen = esmtp = helo_accept_junk = FALSE;
2361 smtp_mailcmd_count = 0;
2362 count_nonmail = TRUE_UNSET;
2363 synprot_error_count = unknown_command_count = nonmail_command_count = 0;
2364 smtp_delay_mail = smtp_rlm_base;
2365 auth_advertised = FALSE;
2366 pipelining_advertised = FALSE;
2367 pipelining_enable = TRUE;
2368 sync_cmd_limit = NON_SYNC_CMD_NON_PIPELINING;
2369 smtp_exit_function_called = FALSE; /* For avoiding loop in not-quit exit */
2371 /* If receiving by -bs from a trusted user, or testing with -bh, we allow
2372 authentication settings from -oMaa to remain in force. */
2374 if (!host_checking && !sender_host_notsocket)
2375 sender_host_auth_pubname = 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 = US 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)
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, US (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 = US (ipopt->__data);
2555 uschar *optstart = US (ipopt->ip_opts);
2557 uschar *optstart = US (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 < US (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)
2820 if (tls_server_start(tls_require_ciphers, &user_msg) != OK)
2821 return smtp_log_tls_fail(user_msg);
2822 cmd_list[CMD_LIST_TLS_AUTH].is_mail_cmd = TRUE;
2826 /* Run the connect ACL if it exists */
2829 if (acl_smtp_connect)
2832 if ((rc = acl_check(ACL_WHERE_CONNECT, NULL, acl_smtp_connect, &user_msg,
2835 (void) smtp_handle_acl_fail(ACL_WHERE_CONNECT, rc, user_msg, log_msg);
2840 /* Output the initial message for a two-way SMTP connection. It may contain
2841 newlines, which then cause a multi-line response to be given. */
2843 code = US"220"; /* Default status code */
2844 esc = US""; /* Default extended status code */
2845 esclen = 0; /* Length of esc */
2849 if (!(s = expand_string(smtp_banner)))
2850 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "Expansion of \"%s\" (smtp_banner) "
2851 "failed: %s", smtp_banner, expand_string_message);
2857 smtp_message_code(&code, &codelen, &s, NULL, TRUE);
2861 esclen = codelen - 4;
2865 /* Remove any terminating newlines; might as well remove trailing space too */
2868 while (p > s && isspace(p[-1])) p--;
2871 /* It seems that CC:Mail is braindead, and assumes that the greeting message
2872 is all contained in a single IP packet. The original code wrote out the
2873 greeting using several calls to fprint/fputc, and on busy servers this could
2874 cause it to be split over more than one packet - which caused CC:Mail to fall
2875 over when it got the second part of the greeting after sending its first
2876 command. Sigh. To try to avoid this, build the complete greeting message
2877 first, and output it in one fell swoop. This gives a better chance of it
2878 ending up as a single packet. */
2880 ss = string_get(256);
2883 do /* At least once, in case we have an empty string */
2886 uschar *linebreak = Ustrchr(p, '\n');
2887 ss = string_catn(ss, code, 3);
2891 ss = string_catn(ss, US" ", 1);
2895 len = linebreak - p;
2896 ss = string_catn(ss, US"-", 1);
2898 ss = string_catn(ss, esc, esclen);
2899 ss = string_catn(ss, p, len);
2900 ss = string_catn(ss, US"\r\n", 2);
2906 /* Before we write the banner, check that there is no input pending, unless
2907 this synchronisation check is disabled. */
2911 unsigned n = smtp_inend - smtp_inptr;
2914 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP protocol "
2915 "synchronization error (input sent without waiting for greeting): "
2916 "rejected connection from %s input=\"%s\"", host_and_ident(TRUE),
2917 string_printing(string_copyn(smtp_inptr, n)));
2918 smtp_printf("554 SMTP synchronization error\r\n", FALSE);
2922 /* Now output the banner */
2924 smtp_printf("%s", FALSE, string_from_gstring(ss));
2926 /* Attempt to see if we sent the banner before the last ACK of the 3-way
2927 handshake arrived. If so we must have managed a TFO. */
2940 /*************************************************
2941 * Handle SMTP syntax and protocol errors *
2942 *************************************************/
2944 /* Write to the log for SMTP syntax errors in incoming commands, if configured
2945 to do so. Then transmit the error response. The return value depends on the
2946 number of syntax and protocol errors in this SMTP session.
2949 type error type, given as a log flag bit
2950 code response code; <= 0 means don't send a response
2951 data data to reflect in the response (can be NULL)
2952 errmess the error message
2954 Returns: -1 limit of syntax/protocol errors NOT exceeded
2955 +1 limit of syntax/protocol errors IS exceeded
2957 These values fit in with the values of the "done" variable in the main
2958 processing loop in smtp_setup_msg(). */
2961 synprot_error(int type, int code, uschar *data, uschar *errmess)
2965 log_write(type, LOG_MAIN, "SMTP %s error in \"%s\" %s %s",
2966 (type == L_smtp_syntax_error)? "syntax" : "protocol",
2967 string_printing(smtp_cmd_buffer), host_and_ident(TRUE), errmess);
2969 if (++synprot_error_count > smtp_max_synprot_errors)
2972 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
2973 "syntax or protocol errors (last command was \"%s\")",
2974 host_and_ident(FALSE), string_printing(smtp_cmd_buffer));
2979 smtp_printf("%d%c%s%s%s\r\n", FALSE, code, yield == 1 ? '-' : ' ',
2980 data ? data : US"", data ? US": " : US"", errmess);
2982 smtp_printf("%d Too many syntax or protocol errors\r\n", FALSE, code);
2991 /*************************************************
2992 * Send SMTP response, possibly multiline *
2993 *************************************************/
2995 /* There are, it seems, broken clients out there that cannot handle multiline
2996 responses. If no_multiline_responses is TRUE (it can be set from an ACL), we
2997 output nothing for non-final calls, and only the first line for anything else.
3000 code SMTP code, may involve extended status codes
3001 codelen length of smtp code; if > 4 there's an ESC
3002 final FALSE if the last line isn't the final line
3003 msg message text, possibly containing newlines
3009 smtp_respond(uschar* code, int codelen, BOOL final, uschar *msg)
3014 if (!final && no_multiline_responses) return;
3019 esclen = codelen - 4;
3022 /* If this is the first output for a (non-batch) RCPT command, see if all RCPTs
3023 have had the same. Note: this code is also present in smtp_printf(). It would
3024 be tidier to have it only in one place, but when it was added, it was easier to
3025 do it that way, so as not to have to mess with the code for the RCPT command,
3026 which sometimes uses smtp_printf() and sometimes smtp_respond(). */
3028 if (rcpt_in_progress)
3030 if (rcpt_smtp_response == NULL)
3031 rcpt_smtp_response = string_copy(msg);
3032 else if (rcpt_smtp_response_same &&
3033 Ustrcmp(rcpt_smtp_response, msg) != 0)
3034 rcpt_smtp_response_same = FALSE;
3035 rcpt_in_progress = FALSE;
3038 /* Now output the message, splitting it up into multiple lines if necessary.
3039 We only handle pipelining these responses as far as nonfinal/final groups,
3040 not the whole MAIL/RCPT/DATA response set. */
3044 uschar *nl = Ustrchr(msg, '\n');
3047 smtp_printf("%.3s%c%.*s%s\r\n", !final, code, final ? ' ':'-', esclen, esc, msg);
3050 else if (nl[1] == 0 || no_multiline_responses)
3052 smtp_printf("%.3s%c%.*s%.*s\r\n", !final, code, final ? ' ':'-', esclen, esc,
3053 (int)(nl - msg), msg);
3058 smtp_printf("%.3s-%.*s%.*s\r\n", TRUE, code, esclen, esc, (int)(nl - msg), msg);
3060 while (isspace(*msg)) msg++;
3068 /*************************************************
3069 * Parse user SMTP message *
3070 *************************************************/
3072 /* This function allows for user messages overriding the response code details
3073 by providing a suitable response code string at the start of the message
3074 user_msg. Check the message for starting with a response code and optionally an
3075 extended status code. If found, check that the first digit is valid, and if so,
3076 change the code pointer and length to use the replacement. An invalid code
3077 causes a panic log; in this case, if the log messages is the same as the user
3078 message, we must also adjust the value of the log message to show the code that
3079 is actually going to be used (the original one).
3081 This function is global because it is called from receive.c as well as within
3084 Note that the code length returned includes the terminating whitespace
3085 character, which is always included in the regex match.
3088 code SMTP code, may involve extended status codes
3089 codelen length of smtp code; if > 4 there's an ESC
3091 log_msg optional log message, to be adjusted with the new SMTP code
3092 check_valid if true, verify the response code
3098 smtp_message_code(uschar **code, int *codelen, uschar **msg, uschar **log_msg,
3104 if (!msg || !*msg) return;
3106 if ((n = pcre_exec(regex_smtp_code, NULL, CS *msg, Ustrlen(*msg), 0,
3107 PCRE_EOPT, ovector, sizeof(ovector)/sizeof(int))) < 0) return;
3109 if (check_valid && (*msg)[0] != (*code)[0])
3111 log_write(0, LOG_MAIN|LOG_PANIC, "configured error code starts with "
3112 "incorrect digit (expected %c) in \"%s\"", (*code)[0], *msg);
3113 if (log_msg != NULL && *log_msg == *msg)
3114 *log_msg = string_sprintf("%s %s", *code, *log_msg + ovector[1]);
3119 *codelen = ovector[1]; /* Includes final space */
3121 *msg += ovector[1]; /* Chop the code off the message */
3128 /*************************************************
3129 * Handle an ACL failure *
3130 *************************************************/
3132 /* This function is called when acl_check() fails. As well as calls from within
3133 this module, it is called from receive.c for an ACL after DATA. It sorts out
3134 logging the incident, and sends the error response. A message containing
3135 newlines is turned into a multiline SMTP response, but for logging, only the
3138 There's a table of default permanent failure response codes to use in
3139 globals.c, along with the table of names. VFRY is special. Despite RFC1123 it
3140 defaults disabled in Exim. However, discussion in connection with RFC 821bis
3141 (aka RFC 2821) has concluded that the response should be 252 in the disabled
3142 state, because there are broken clients that try VRFY before RCPT. A 5xx
3143 response should be given only when the address is positively known to be
3144 undeliverable. Sigh. We return 252 if there is no VRFY ACL or it provides
3145 no explicit code, but if there is one we let it know best.
3146 Also, for ETRN, 458 is given on refusal, and for AUTH, 503.
3148 From Exim 4.63, it is possible to override the response code details by
3149 providing a suitable response code string at the start of the message provided
3150 in user_msg. The code's first digit is checked for validity.
3153 where where the ACL was called from
3155 user_msg a message that can be included in an SMTP response
3156 log_msg a message for logging
3158 Returns: 0 in most cases
3159 2 if the failure code was FAIL_DROP, in which case the
3160 SMTP connection should be dropped (this value fits with the
3161 "done" variable in smtp_setup_msg() below)
3165 smtp_handle_acl_fail(int where, int rc, uschar *user_msg, uschar *log_msg)
3167 BOOL drop = rc == FAIL_DROP;
3171 uschar *sender_info = US"";
3173 #ifdef WITH_CONTENT_SCAN
3174 where == ACL_WHERE_MIME ? US"during MIME ACL checks" :
3176 where == ACL_WHERE_PREDATA ? US"DATA" :
3177 where == ACL_WHERE_DATA ? US"after DATA" :
3178 #ifndef DISABLE_PRDR
3179 where == ACL_WHERE_PRDR ? US"after DATA PRDR" :
3182 string_sprintf("%s %s", acl_wherenames[where], smtp_cmd_data) :
3183 string_sprintf("%s in \"connect\" ACL", acl_wherenames[where]);
3185 if (drop) rc = FAIL;
3187 /* Set the default SMTP code, and allow a user message to change it. */
3189 smtp_code = rc == FAIL ? acl_wherecodes[where] : US"451";
3190 smtp_message_code(&smtp_code, &codelen, &user_msg, &log_msg,
3191 where != ACL_WHERE_VRFY);
3193 /* We used to have sender_address here; however, there was a bug that was not
3194 updating sender_address after a rewrite during a verify. When this bug was
3195 fixed, sender_address at this point became the rewritten address. I'm not sure
3196 this is what should be logged, so I've changed to logging the unrewritten
3197 address to retain backward compatibility. */
3199 #ifndef WITH_CONTENT_SCAN
3200 if (where == ACL_WHERE_RCPT || where == ACL_WHERE_DATA)
3202 if (where == ACL_WHERE_RCPT || where == ACL_WHERE_DATA || where == ACL_WHERE_MIME)
3205 sender_info = string_sprintf("F=<%s>%s%s%s%s ",
3206 sender_address_unrewritten ? sender_address_unrewritten : sender_address,
3207 sender_host_authenticated ? US" A=" : US"",
3208 sender_host_authenticated ? sender_host_authenticated : US"",
3209 sender_host_authenticated && authenticated_id ? US":" : US"",
3210 sender_host_authenticated && authenticated_id ? authenticated_id : US""
3214 /* If there's been a sender verification failure with a specific message, and
3215 we have not sent a response about it yet, do so now, as a preliminary line for
3216 failures, but not defers. However, always log it for defer, and log it for fail
3217 unless the sender_verify_fail log selector has been turned off. */
3219 if (sender_verified_failed &&
3220 !testflag(sender_verified_failed, af_sverify_told))
3222 BOOL save_rcpt_in_progress = rcpt_in_progress;
3223 rcpt_in_progress = FALSE; /* So as not to treat these as the error */
3225 setflag(sender_verified_failed, af_sverify_told);
3227 if (rc != FAIL || LOGGING(sender_verify_fail))
3228 log_write(0, LOG_MAIN|LOG_REJECT, "%s sender verify %s for <%s>%s",
3229 host_and_ident(TRUE),
3230 ((sender_verified_failed->special_action & 255) == DEFER)? "defer":"fail",
3231 sender_verified_failed->address,
3232 (sender_verified_failed->message == NULL)? US"" :
3233 string_sprintf(": %s", sender_verified_failed->message));
3235 if (rc == FAIL && sender_verified_failed->user_message)
3236 smtp_respond(smtp_code, codelen, FALSE, string_sprintf(
3237 testflag(sender_verified_failed, af_verify_pmfail)?
3238 "Postmaster verification failed while checking <%s>\n%s\n"
3239 "Several RFCs state that you are required to have a postmaster\n"
3240 "mailbox for each mail domain. This host does not accept mail\n"
3241 "from domains whose servers reject the postmaster address."
3243 testflag(sender_verified_failed, af_verify_nsfail)?
3244 "Callback setup failed while verifying <%s>\n%s\n"
3245 "The initial connection, or a HELO or MAIL FROM:<> command was\n"
3246 "rejected. Refusing MAIL FROM:<> does not help fight spam, disregards\n"
3247 "RFC requirements, and stops you from receiving standard bounce\n"
3248 "messages. This host does not accept mail from domains whose servers\n"
3251 "Verification failed for <%s>\n%s",
3252 sender_verified_failed->address,
3253 sender_verified_failed->user_message));
3255 rcpt_in_progress = save_rcpt_in_progress;
3258 /* Sort out text for logging */
3260 log_msg = log_msg ? string_sprintf(": %s", log_msg) : US"";
3261 if ((lognl = Ustrchr(log_msg, '\n'))) *lognl = 0;
3263 /* Send permanent failure response to the command, but the code used isn't
3264 always a 5xx one - see comments at the start of this function. If the original
3265 rc was FAIL_DROP we drop the connection and yield 2. */
3268 smtp_respond(smtp_code, codelen, TRUE,
3269 user_msg ? user_msg : US"Administrative prohibition");
3271 /* Send temporary failure response to the command. Don't give any details,
3272 unless acl_temp_details is set. This is TRUE for a callout defer, a "defer"
3273 verb, and for a header verify when smtp_return_error_details is set.
3275 This conditional logic is all somewhat of a mess because of the odd
3276 interactions between temp_details and return_error_details. One day it should
3277 be re-implemented in a tidier fashion. */
3280 if (acl_temp_details && user_msg)
3282 if ( smtp_return_error_details
3283 && sender_verified_failed
3284 && sender_verified_failed->message
3286 smtp_respond(smtp_code, codelen, FALSE, sender_verified_failed->message);
3288 smtp_respond(smtp_code, codelen, TRUE, user_msg);
3291 smtp_respond(smtp_code, codelen, TRUE,
3292 US"Temporary local problem - please try later");
3294 /* Log the incident to the logs that are specified by log_reject_target
3295 (default main, reject). This can be empty to suppress logging of rejections. If
3296 the connection is not forcibly to be dropped, return 0. Otherwise, log why it
3297 is closing if required and return 2. */
3299 if (log_reject_target != 0)
3302 gstring * g = s_tlslog(NULL);
3303 uschar * tls = string_from_gstring(g);
3304 if (!tls) tls = US"";
3306 uschar * tls = US"";
3308 log_write(where == ACL_WHERE_CONNECT ? L_connection_reject : 0,
3309 log_reject_target, "%s%s%s %s%srejected %s%s",
3310 LOGGING(dnssec) && sender_host_dnssec ? US" DS" : US"",
3311 host_and_ident(TRUE),
3314 rc == FAIL ? US"" : US"temporarily ",
3318 if (!drop) return 0;
3320 log_write(L_smtp_connection, LOG_MAIN, "%s closed by DROP in ACL",
3321 smtp_get_connection_info());
3323 /* Run the not-quit ACL, but without any custom messages. This should not be a
3324 problem, because we get here only if some other ACL has issued "drop", and
3325 in that case, *its* custom messages will have been used above. */
3327 smtp_notquit_exit(US"acl-drop", NULL, NULL);
3334 /*************************************************
3335 * Handle SMTP exit when QUIT is not given *
3336 *************************************************/
3338 /* This function provides a logging/statistics hook for when an SMTP connection
3339 is dropped on the floor or the other end goes away. It's a global function
3340 because it's called from receive.c as well as this module. As well as running
3341 the NOTQUIT ACL, if there is one, this function also outputs a final SMTP
3342 response, either with a custom message from the ACL, or using a default. There
3343 is one case, however, when no message is output - after "drop". In that case,
3344 the ACL that obeyed "drop" has already supplied the custom message, and NULL is
3345 passed to this function.
3347 In case things go wrong while processing this function, causing an error that
3348 may re-enter this function, there is a recursion check.
3351 reason What $smtp_notquit_reason will be set to in the ACL;
3352 if NULL, the ACL is not run
3353 code The error code to return as part of the response
3354 defaultrespond The default message if there's no user_msg
3360 smtp_notquit_exit(uschar *reason, uschar *code, uschar *defaultrespond, ...)
3363 uschar *user_msg = NULL;
3364 uschar *log_msg = NULL;
3366 /* Check for recursive acll */
3368 if (smtp_exit_function_called)
3370 log_write(0, LOG_PANIC, "smtp_notquit_exit() called more than once (%s)",
3374 smtp_exit_function_called = TRUE;
3376 /* Call the not-QUIT ACL, if there is one, unless no reason is given. */
3378 if (acl_smtp_notquit && reason)
3380 smtp_notquit_reason = reason;
3381 if ((rc = acl_check(ACL_WHERE_NOTQUIT, NULL, acl_smtp_notquit, &user_msg,
3382 &log_msg)) == ERROR)
3383 log_write(0, LOG_MAIN|LOG_PANIC, "ACL for not-QUIT returned ERROR: %s",
3387 /* Write an SMTP response if we are expected to give one. As the default
3388 responses are all internal, they should always fit in the buffer, but code a
3389 warning, just in case. Note that string_vformat() still leaves a complete
3390 string, even if it is incomplete. */
3392 if (code && defaultrespond)
3395 smtp_respond(code, 3, TRUE, user_msg);
3400 va_start(ap, defaultrespond);
3401 if (!string_vformat(buffer, sizeof(buffer), CS defaultrespond, ap))
3402 log_write(0, LOG_MAIN|LOG_PANIC, "string too large in smtp_notquit_exit()");
3403 smtp_printf("%s %s\r\n", FALSE, code, buffer);
3413 /*************************************************
3414 * Verify HELO argument *
3415 *************************************************/
3417 /* This function is called if helo_verify_hosts or helo_try_verify_hosts is
3418 matched. It is also called from ACL processing if verify = helo is used and
3419 verification was not previously tried (i.e. helo_try_verify_hosts was not
3420 matched). The result of its processing is to set helo_verified and
3421 helo_verify_failed. These variables should both be FALSE for this function to
3424 Note that EHLO/HELO is legitimately allowed to quote an address literal. Allow
3425 for IPv6 ::ffff: literals.
3428 Returns: TRUE if testing was completed;
3429 FALSE on a temporary failure
3433 smtp_verify_helo(void)
3437 HDEBUG(D_receive) debug_printf("verifying EHLO/HELO argument \"%s\"\n",
3440 if (sender_helo_name == NULL)
3442 HDEBUG(D_receive) debug_printf("no EHLO/HELO command was issued\n");
3445 /* Deal with the case of -bs without an IP address */
3447 else if (sender_host_address == NULL)
3449 HDEBUG(D_receive) debug_printf("no client IP address: assume success\n");
3450 helo_verified = TRUE;
3453 /* Deal with the more common case when there is a sending IP address */
3455 else if (sender_helo_name[0] == '[')
3457 helo_verified = Ustrncmp(sender_helo_name+1, sender_host_address,
3458 Ustrlen(sender_host_address)) == 0;
3463 if (strncmpic(sender_host_address, US"::ffff:", 7) == 0)
3464 helo_verified = Ustrncmp(sender_helo_name + 1,
3465 sender_host_address + 7, Ustrlen(sender_host_address) - 7) == 0;
3470 { if (helo_verified) debug_printf("matched host address\n"); }
3473 /* Do a reverse lookup if one hasn't already given a positive or negative
3474 response. If that fails, or the name doesn't match, try checking with a forward
3479 if (sender_host_name == NULL && !host_lookup_failed)
3480 yield = host_name_lookup() != DEFER;
3482 /* If a host name is known, check it and all its aliases. */
3484 if (sender_host_name)
3485 if ((helo_verified = strcmpic(sender_host_name, sender_helo_name) == 0))
3487 sender_helo_dnssec = sender_host_dnssec;
3488 HDEBUG(D_receive) debug_printf("matched host name\n");
3492 uschar **aliases = sender_host_aliases;
3494 if ((helo_verified = strcmpic(*aliases++, sender_helo_name) == 0))
3496 sender_helo_dnssec = sender_host_dnssec;
3500 HDEBUG(D_receive) if (helo_verified)
3501 debug_printf("matched alias %s\n", *(--aliases));
3504 /* Final attempt: try a forward lookup of the helo name */
3513 h.name = sender_helo_name;
3520 HDEBUG(D_receive) debug_printf("getting IP address for %s\n",
3522 rc = host_find_bydns(&h, NULL, HOST_FIND_BY_A | HOST_FIND_BY_AAAA,
3523 NULL, NULL, NULL, &d, NULL, NULL);
3524 if (rc == HOST_FOUND || rc == HOST_FOUND_LOCAL)
3525 for (hh = &h; hh; hh = hh->next)
3526 if (Ustrcmp(hh->address, sender_host_address) == 0)
3528 helo_verified = TRUE;
3529 if (h.dnssec == DS_YES) sender_helo_dnssec = TRUE;
3532 debug_printf("IP address for %s matches calling address\n"
3533 "Forward DNS security status: %sverified\n",
3534 sender_helo_name, sender_helo_dnssec ? "" : "un");
3541 if (!helo_verified) helo_verify_failed = TRUE; /* We've tried ... */
3548 /*************************************************
3549 * Send user response message *
3550 *************************************************/
3552 /* This function is passed a default response code and a user message. It calls
3553 smtp_message_code() to check and possibly modify the response code, and then
3554 calls smtp_respond() to transmit the response. I put this into a function
3555 just to avoid a lot of repetition.
3558 code the response code
3559 user_msg the user message
3565 smtp_user_msg(uschar *code, uschar *user_msg)
3568 smtp_message_code(&code, &len, &user_msg, NULL, TRUE);
3569 smtp_respond(code, len, TRUE, user_msg);
3575 smtp_in_auth(auth_instance *au, uschar ** s, uschar ** ss)
3577 const uschar *set_id = NULL;
3580 /* Run the checking code, passing the remainder of the command line as
3581 data. Initials the $auth<n> variables as empty. Initialize $0 empty and set
3582 it as the only set numerical variable. The authenticator may set $auth<n>
3583 and also set other numeric variables. The $auth<n> variables are preferred
3584 nowadays; the numerical variables remain for backwards compatibility.
3586 Afterwards, have a go at expanding the set_id string, even if
3587 authentication failed - for bad passwords it can be useful to log the
3588 userid. On success, require set_id to expand and exist, and put it in
3589 authenticated_id. Save this in permanent store, as the working store gets
3590 reset at HELO, RSET, etc. */
3592 for (i = 0; i < AUTH_VARS; i++) auth_vars[i] = NULL;
3594 expand_nlength[0] = 0; /* $0 contains nothing */
3596 rc = (au->info->servercode)(au, smtp_cmd_data);
3597 if (au->set_id) set_id = expand_string(au->set_id);
3598 expand_nmax = -1; /* Reset numeric variables */
3599 for (i = 0; i < AUTH_VARS; i++) auth_vars[i] = NULL; /* Reset $auth<n> */
3601 /* The value of authenticated_id is stored in the spool file and printed in
3602 log lines. It must not contain binary zeros or newline characters. In
3603 normal use, it never will, but when playing around or testing, this error
3604 can (did) happen. To guard against this, ensure that the id contains only
3605 printing characters. */
3607 if (set_id) set_id = string_printing(set_id);
3609 /* For the non-OK cases, set up additional logging data if set_id
3613 set_id = set_id && *set_id
3614 ? string_sprintf(" (set_id=%s)", set_id) : US"";
3616 /* Switch on the result */
3621 if (!au->set_id || set_id) /* Complete success */
3623 if (set_id) authenticated_id = string_copy_malloc(set_id);
3624 sender_host_authenticated = au->name;
3625 sender_host_auth_pubname = au->public_name;
3626 authentication_failed = FALSE;
3627 authenticated_fail_id = NULL; /* Impossible to already be set? */
3630 (sender_host_address ? protocols : protocols_local)
3631 [pextend + pauthed + (tls_in.active >= 0 ? pcrpted:0)];
3632 *s = *ss = US"235 Authentication succeeded";
3633 authenticated_by = au;
3637 /* Authentication succeeded, but we failed to expand the set_id string.
3638 Treat this as a temporary error. */
3640 auth_defer_msg = expand_string_message;
3644 if (set_id) authenticated_fail_id = string_copy_malloc(set_id);
3645 *s = string_sprintf("435 Unable to authenticate at present%s",
3646 auth_defer_user_msg);
3647 *ss = string_sprintf("435 Unable to authenticate at present%s: %s",
3648 set_id, auth_defer_msg);
3652 *s = *ss = US"501 Invalid base64 data";
3656 *s = *ss = US"501 Authentication cancelled";
3660 *s = *ss = US"553 Initial data not expected";
3664 if (set_id) authenticated_fail_id = string_copy_malloc(set_id);
3665 *s = US"535 Incorrect authentication data";
3666 *ss = string_sprintf("535 Incorrect authentication data%s", set_id);
3670 if (set_id) authenticated_fail_id = string_copy_malloc(set_id);
3671 *s = US"435 Internal error";
3672 *ss = string_sprintf("435 Internal error%s: return %d from authentication "
3673 "check", set_id, rc);
3685 qualify_recipient(uschar ** recipient, uschar * smtp_cmd_data, uschar * tag)
3688 if (allow_unqualified_recipient || strcmpic(*recipient, US"postmaster") == 0)
3690 DEBUG(D_receive) debug_printf("unqualified address %s accepted\n",
3692 rd = Ustrlen(recipient) + 1;
3693 *recipient = rewrite_address_qualify(*recipient, TRUE);
3696 smtp_printf("501 %s: recipient address must contain a domain\r\n", FALSE,
3698 log_write(L_smtp_syntax_error,
3699 LOG_MAIN|LOG_REJECT, "unqualified %s rejected: <%s> %s%s",
3700 tag, *recipient, host_and_ident(TRUE), host_lookup_msg);
3708 smtp_quit_handler(uschar ** user_msgp, uschar ** log_msgp)
3711 incomplete_transaction_log(US"QUIT");
3714 int rc = acl_check(ACL_WHERE_QUIT, NULL, acl_smtp_quit, user_msgp, log_msgp);
3716 log_write(0, LOG_MAIN|LOG_PANIC, "ACL for QUIT returned ERROR: %s",
3720 smtp_respond(US"221", 3, TRUE, *user_msgp);
3722 smtp_printf("221 %s closing connection\r\n", FALSE, smtp_active_hostname);
3725 tls_close(TRUE, TLS_SHUTDOWN_NOWAIT);
3728 log_write(L_smtp_connection, LOG_MAIN, "%s closed by QUIT",
3729 smtp_get_connection_info());
3734 smtp_rset_handler(void)
3737 incomplete_transaction_log(US"RSET");
3738 smtp_printf("250 Reset OK\r\n", FALSE);
3739 cmd_list[CMD_LIST_RSET].is_mail_cmd = FALSE;
3744 /*************************************************
3745 * Initialize for SMTP incoming message *
3746 *************************************************/
3748 /* This function conducts the initial dialogue at the start of an incoming SMTP
3749 message, and builds a list of recipients. However, if the incoming message
3750 is part of a batch (-bS option) a separate function is called since it would
3751 be messy having tests splattered about all over this function. This function
3752 therefore handles the case where interaction is occurring. The input and output
3753 files are set up in smtp_in and smtp_out.
3755 The global recipients_list is set to point to a vector of recipient_item
3756 blocks, whose number is given by recipients_count. This is extended by the
3757 receive_add_recipient() function. The global variable sender_address is set to
3758 the sender's address. The yield is +1 if a message has been successfully
3759 started, 0 if a QUIT command was encountered or the connection was refused from
3760 the particular host, or -1 if the connection was lost.
3764 Returns: > 0 message successfully started (reached DATA)
3765 = 0 QUIT read or end of file reached or call refused
3770 smtp_setup_msg(void)
3773 BOOL toomany = FALSE;
3774 BOOL discarded = FALSE;
3775 BOOL last_was_rej_mail = FALSE;
3776 BOOL last_was_rcpt = FALSE;
3777 void *reset_point = store_get(0);
3779 DEBUG(D_receive) debug_printf("smtp_setup_msg entered\n");
3781 /* Reset for start of new message. We allow one RSET not to be counted as a
3782 nonmail command, for those MTAs that insist on sending it between every
3783 message. Ditto for EHLO/HELO and for STARTTLS, to allow for going in and out of
3784 TLS between messages (an Exim client may do this if it has messages queued up
3785 for the host). Note: we do NOT reset AUTH at this point. */
3787 smtp_reset(reset_point);
3788 message_ended = END_NOTSTARTED;
3790 chunking_state = chunking_offered ? CHUNKING_OFFERED : CHUNKING_NOT_OFFERED;
3792 cmd_list[CMD_LIST_RSET].is_mail_cmd = TRUE;
3793 cmd_list[CMD_LIST_HELO].is_mail_cmd = TRUE;
3794 cmd_list[CMD_LIST_EHLO].is_mail_cmd = TRUE;
3796 cmd_list[CMD_LIST_STARTTLS].is_mail_cmd = TRUE;
3799 /* Set the local signal handler for SIGTERM - it tries to end off tidily */
3801 os_non_restarting_signal(SIGTERM, command_sigterm_handler);
3803 /* Batched SMTP is handled in a different function. */
3805 if (smtp_batched_input) return smtp_setup_batch_msg();
3807 /* Deal with SMTP commands. This loop is exited by setting done to a POSITIVE
3808 value. The values are 2 larger than the required yield of the function. */
3812 const uschar **argv;
3813 uschar *etrn_command;
3814 uschar *etrn_serialize_key;
3816 uschar *log_msg, *smtp_code;
3817 uschar *user_msg = NULL;
3818 uschar *recipient = NULL;
3819 uschar *hello = NULL;
3821 BOOL was_rej_mail = FALSE;
3822 BOOL was_rcpt = FALSE;
3823 void (*oldsignal)(int);
3825 int start, end, sender_domain, recipient_domain;
3829 uschar *orcpt = NULL;
3834 /* Check once per STARTTLS or SSL-on-connect for a TLS AUTH */
3835 if ( tls_in.active >= 0
3837 && tls_in.certificate_verified
3838 && cmd_list[CMD_LIST_TLS_AUTH].is_mail_cmd
3841 cmd_list[CMD_LIST_TLS_AUTH].is_mail_cmd = FALSE;
3843 for (au = auths; au; au = au->next)
3844 if (strcmpic(US"tls", au->driver_name) == 0)
3847 && (rc = acl_check(ACL_WHERE_AUTH, NULL, acl_smtp_auth,
3848 &user_msg, &log_msg)) != OK
3850 done = smtp_handle_acl_fail(ACL_WHERE_AUTH, rc, user_msg, log_msg);
3853 smtp_cmd_data = NULL;
3855 if (smtp_in_auth(au, &s, &ss) == OK)
3856 { DEBUG(D_auth) debug_printf("tls auth succeeded\n"); }
3858 { DEBUG(D_auth) debug_printf("tls auth not succeeded\n"); }
3866 if (smtp_in) /* Avoid pure-ACKs while in cmd pingpong phase */
3867 (void) setsockopt(fileno(smtp_in), IPPROTO_TCP, TCP_QUICKACK,
3868 US &off, sizeof(off));
3871 switch(smtp_read_command(TRUE, GETC_BUFFER_UNLIMITED))
3873 /* The AUTH command is not permitted to occur inside a transaction, and may
3874 occur successfully only once per connection. Actually, that isn't quite
3875 true. When TLS is started, all previous information about a connection must
3876 be discarded, so a new AUTH is permitted at that time.
3878 AUTH may only be used when it has been advertised. However, it seems that
3879 there are clients that send AUTH when it hasn't been advertised, some of
3880 them even doing this after HELO. And there are MTAs that accept this. Sigh.
3881 So there's a get-out that allows this to happen.
3883 AUTH is initially labelled as a "nonmail command" so that one occurrence
3884 doesn't get counted. We change the label here so that multiple failing
3885 AUTHS will eventually hit the nonmail threshold. */
3889 authentication_failed = TRUE;
3890 cmd_list[CMD_LIST_AUTH].is_mail_cmd = FALSE;
3892 if (!auth_advertised && !allow_auth_unadvertised)
3894 done = synprot_error(L_smtp_protocol_error, 503, NULL,
3895 US"AUTH command used when not advertised");
3898 if (sender_host_authenticated)
3900 done = synprot_error(L_smtp_protocol_error, 503, NULL,
3901 US"already authenticated");
3906 done = synprot_error(L_smtp_protocol_error, 503, NULL,
3907 US"not permitted in mail transaction");
3914 && (rc = acl_check(ACL_WHERE_AUTH, NULL, acl_smtp_auth,
3915 &user_msg, &log_msg)) != OK
3918 done = smtp_handle_acl_fail(ACL_WHERE_AUTH, rc, user_msg, log_msg);
3922 /* Find the name of the requested authentication mechanism. */
3925 while ((c = *smtp_cmd_data) != 0 && !isspace(c))
3927 if (!isalnum(c) && c != '-' && c != '_')
3929 done = synprot_error(L_smtp_syntax_error, 501, NULL,
3930 US"invalid character in authentication mechanism name");
3936 /* If not at the end of the line, we must be at white space. Terminate the
3937 name and move the pointer on to any data that may be present. */
3939 if (*smtp_cmd_data != 0)
3941 *smtp_cmd_data++ = 0;
3942 while (isspace(*smtp_cmd_data)) smtp_cmd_data++;
3945 /* Search for an authentication mechanism which is configured for use
3946 as a server and which has been advertised (unless, sigh, allow_auth_
3947 unadvertised is set). */
3949 for (au = auths; au; au = au->next)
3950 if (strcmpic(s, au->public_name) == 0 && au->server &&
3951 (au->advertised || allow_auth_unadvertised))
3956 c = smtp_in_auth(au, &s, &ss);
3958 smtp_printf("%s\r\n", FALSE, s);
3960 log_write(0, LOG_MAIN|LOG_REJECT, "%s authenticator failed for %s: %s",
3961 au->name, host_and_ident(FALSE), ss);
3964 done = synprot_error(L_smtp_protocol_error, 504, NULL,
3965 string_sprintf("%s authentication mechanism not supported", s));
3967 break; /* AUTH_CMD */
3969 /* The HELO/EHLO commands are permitted to appear in the middle of a
3970 session as well as at the beginning. They have the effect of a reset in
3971 addition to their other functions. Their absence at the start cannot be
3972 taken to be an error.
3976 If the EHLO command is not acceptable to the SMTP server, 501, 500,
3977 or 502 failure replies MUST be returned as appropriate. The SMTP
3978 server MUST stay in the same state after transmitting these replies
3979 that it was in before the EHLO was received.
3981 Therefore, we do not do the reset until after checking the command for
3982 acceptability. This change was made for Exim release 4.11. Previously
3983 it did the reset first. */
3996 HELO_EHLO: /* Common code for HELO and EHLO */
3997 cmd_list[CMD_LIST_HELO].is_mail_cmd = FALSE;
3998 cmd_list[CMD_LIST_EHLO].is_mail_cmd = FALSE;
4000 /* Reject the HELO if its argument was invalid or non-existent. A
4001 successful check causes the argument to be saved in malloc store. */
4003 if (!check_helo(smtp_cmd_data))
4005 smtp_printf("501 Syntactically invalid %s argument(s)\r\n", FALSE, hello);
4007 log_write(0, LOG_MAIN|LOG_REJECT, "rejected %s from %s: syntactically "
4008 "invalid argument(s): %s", hello, host_and_ident(FALSE),
4009 (*smtp_cmd_argument == 0)? US"(no argument given)" :
4010 string_printing(smtp_cmd_argument));
4012 if (++synprot_error_count > smtp_max_synprot_errors)
4014 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
4015 "syntax or protocol errors (last command was \"%s\")",
4016 host_and_ident(FALSE), string_printing(smtp_cmd_buffer));
4023 /* If sender_host_unknown is true, we have got here via the -bs interface,
4024 not called from inetd. Otherwise, we are running an IP connection and the
4025 host address will be set. If the helo name is the primary name of this
4026 host and we haven't done a reverse lookup, force one now. If helo_required
4027 is set, ensure that the HELO name matches the actual host. If helo_verify
4028 is set, do the same check, but softly. */
4030 if (!sender_host_unknown)
4032 BOOL old_helo_verified = helo_verified;
4033 uschar *p = smtp_cmd_data;
4035 while (*p != 0 && !isspace(*p)) { *p = tolower(*p); p++; }
4038 /* Force a reverse lookup if HELO quoted something in helo_lookup_domains
4039 because otherwise the log can be confusing. */
4041 if ( !sender_host_name
4042 && (deliver_domain = sender_helo_name, /* set $domain */
4043 match_isinlist(sender_helo_name, CUSS &helo_lookup_domains, 0,
4044 &domainlist_anchor, NULL, MCL_DOMAIN, TRUE, NULL)) == OK)
4045 (void)host_name_lookup();
4047 /* Rebuild the fullhost info to include the HELO name (and the real name
4048 if it was looked up.) */
4050 host_build_sender_fullhost(); /* Rebuild */
4051 set_process_info("handling%s incoming connection from %s",
4052 (tls_in.active >= 0)? " TLS" : "", host_and_ident(FALSE));
4054 /* Verify if configured. This doesn't give much security, but it does
4055 make some people happy to be able to do it. If helo_required is set,
4056 (host matches helo_verify_hosts) failure forces rejection. If helo_verify
4057 is set (host matches helo_try_verify_hosts), it does not. This is perhaps
4058 now obsolescent, since the verification can now be requested selectively
4061 helo_verified = helo_verify_failed = sender_helo_dnssec = FALSE;
4062 if (helo_required || helo_verify)
4064 BOOL tempfail = !smtp_verify_helo();
4069 smtp_printf("%d %s argument does not match calling host\r\n", FALSE,
4070 tempfail? 451 : 550, hello);
4071 log_write(0, LOG_MAIN|LOG_REJECT, "%srejected \"%s %s\" from %s",
4072 tempfail? "temporarily " : "",
4073 hello, sender_helo_name, host_and_ident(FALSE));
4074 helo_verified = old_helo_verified;
4075 break; /* End of HELO/EHLO processing */
4077 HDEBUG(D_all) debug_printf("%s verification failed but host is in "
4078 "helo_try_verify_hosts\n", hello);
4084 /* set up SPF context */
4085 spf_init(sender_helo_name, sender_host_address);
4088 /* Apply an ACL check if one is defined; afterwards, recheck
4089 synchronization in case the client started sending in a delay. */
4092 if ((rc = acl_check(ACL_WHERE_HELO, NULL, acl_smtp_helo,
4093 &user_msg, &log_msg)) != OK)
4095 done = smtp_handle_acl_fail(ACL_WHERE_HELO, rc, user_msg, log_msg);
4096 if (sender_helo_name)
4098 store_free(sender_helo_name);
4099 sender_helo_name = NULL;
4101 host_build_sender_fullhost(); /* Rebuild */
4104 else if (!check_sync()) goto SYNC_FAILURE;
4106 /* Generate an OK reply. The default string includes the ident if present,
4107 and also the IP address if present. Reflecting back the ident is intended
4108 as a deterrent to mail forgers. For maximum efficiency, and also because
4109 some broken systems expect each response to be in a single packet, arrange
4110 that the entire reply is sent in one write(). */
4112 auth_advertised = FALSE;
4113 pipelining_advertised = FALSE;
4115 tls_advertised = FALSE;
4117 dsn_advertised = FALSE;
4119 smtputf8_advertised = FALSE;
4122 smtp_code = US"250 "; /* Default response code plus space*/
4125 s = string_sprintf("%.3s %s Hello %s%s%s",
4127 smtp_active_hostname,
4128 sender_ident ? sender_ident : US"",
4129 sender_ident ? US" at " : US"",
4130 sender_host_name ? sender_host_name : sender_helo_name);
4131 g = string_cat(NULL, s);
4133 if (sender_host_address)
4135 g = string_catn(g, US" [", 2);
4136 g = string_cat (g, sender_host_address);
4137 g = string_catn(g, US"]", 1);
4141 /* A user-supplied EHLO greeting may not contain more than one line. Note
4142 that the code returned by smtp_message_code() includes the terminating
4143 whitespace character. */
4149 smtp_message_code(&smtp_code, &codelen, &user_msg, NULL, TRUE);
4150 s = string_sprintf("%.*s%s", codelen, smtp_code, user_msg);
4151 if ((ss = strpbrk(CS s, "\r\n")) != NULL)
4153 log_write(0, LOG_MAIN|LOG_PANIC, "EHLO/HELO response must not contain "
4154 "newlines: message truncated: %s", string_printing(s));
4157 g = string_cat(NULL, s);
4160 g = string_catn(g, US"\r\n", 2);
4162 /* If we received EHLO, we must create a multiline response which includes
4163 the functions supported. */
4169 /* I'm not entirely happy with this, as an MTA is supposed to check
4170 that it has enough room to accept a message of maximum size before
4171 it sends this. However, there seems little point in not sending it.
4172 The actual size check happens later at MAIL FROM time. By postponing it
4173 till then, VRFY and EXPN can be used after EHLO when space is short. */
4175 if (thismessage_size_limit > 0)
4177 sprintf(CS big_buffer, "%.3s-SIZE %d\r\n", smtp_code,
4178 thismessage_size_limit);
4179 g = string_cat(g, big_buffer);
4183 g = string_catn(g, smtp_code, 3);
4184 g = string_catn(g, US"-SIZE\r\n", 7);
4187 /* Exim does not do protocol conversion or data conversion. It is 8-bit
4188 clean; if it has an 8-bit character in its hand, it just sends it. It
4189 cannot therefore specify 8BITMIME and remain consistent with the RFCs.
4190 However, some users want this option simply in order to stop MUAs
4191 mangling messages that contain top-bit-set characters. It is therefore
4192 provided as an option. */
4194 if (accept_8bitmime)
4196 g = string_catn(g, smtp_code, 3);
4197 g = string_catn(g, US"-8BITMIME\r\n", 11);
4200 /* Advertise DSN support if configured to do so. */
4201 if (verify_check_host(&dsn_advertise_hosts) != FAIL)
4203 g = string_catn(g, smtp_code, 3);
4204 g = string_catn(g, US"-DSN\r\n", 6);
4205 dsn_advertised = TRUE;
4208 /* Advertise ETRN/VRFY/EXPN if there's are ACL checking whether a host is
4209 permitted to issue them; a check is made when any host actually tries. */
4213 g = string_catn(g, smtp_code, 3);
4214 g = string_catn(g, US"-ETRN\r\n", 7);
4218 g = string_catn(g, smtp_code, 3);
4219 g = string_catn(g, US"-VRFY\r\n", 7);
4223 g = string_catn(g, smtp_code, 3);
4224 g = string_catn(g, US"-EXPN\r\n", 7);
4227 /* Exim is quite happy with pipelining, so let the other end know that
4228 it is safe to use it, unless advertising is disabled. */
4230 if (pipelining_enable &&
4231 verify_check_host(&pipelining_advertise_hosts) == OK)
4233 g = string_catn(g, smtp_code, 3);
4234 g = string_catn(g, US"-PIPELINING\r\n", 13);
4235 sync_cmd_limit = NON_SYNC_CMD_PIPELINING;
4236 pipelining_advertised = TRUE;
4240 /* If any server authentication mechanisms are configured, advertise
4241 them if the current host is in auth_advertise_hosts. The problem with
4242 advertising always is that some clients then require users to
4243 authenticate (and aren't configurable otherwise) even though it may not
4244 be necessary (e.g. if the host is in host_accept_relay).
4246 RFC 2222 states that SASL mechanism names contain only upper case
4247 letters, so output the names in upper case, though we actually recognize
4248 them in either case in the AUTH command. */
4252 && !sender_host_authenticated
4254 && verify_check_host(&auth_advertise_hosts) == OK
4259 for (au = auths; au; au = au->next)
4261 au->advertised = FALSE;
4264 DEBUG(D_auth+D_expand) debug_printf_indent(
4265 "Evaluating advertise_condition for %s athenticator\n",
4267 if ( !au->advertise_condition
4268 || expand_check_condition(au->advertise_condition, au->name,
4275 g = string_catn(g, smtp_code, 3);
4276 g = string_catn(g, US"-AUTH", 5);
4278 auth_advertised = TRUE;
4281 g = string_catn(g, US" ", 1);
4282 g = string_cat (g, au->public_name);
4283 while (++saveptr < g->ptr) g->s[saveptr] = toupper(g->s[saveptr]);
4284 au->advertised = TRUE;
4289 if (!first) g = string_catn(g, US"\r\n", 2);
4292 /* RFC 3030 CHUNKING */
4294 if (verify_check_host(&chunking_advertise_hosts) != FAIL)
4296 g = string_catn(g, smtp_code, 3);
4297 g = string_catn(g, US"-CHUNKING\r\n", 11);
4298 chunking_offered = TRUE;
4299 chunking_state = CHUNKING_OFFERED;
4302 /* Advertise TLS (Transport Level Security) aka SSL (Secure Socket Layer)
4303 if it has been included in the binary, and the host matches
4304 tls_advertise_hosts. We must *not* advertise if we are already in a
4305 secure connection. */
4308 if (tls_in.active < 0 &&
4309 verify_check_host(&tls_advertise_hosts) != FAIL)
4311 g = string_catn(g, smtp_code, 3);
4312 g = string_catn(g, US"-STARTTLS\r\n", 11);
4313 tls_advertised = TRUE;
4317 #ifndef DISABLE_PRDR
4318 /* Per Recipient Data Response, draft by Eric A. Hall extending RFC */
4321 g = string_catn(g, smtp_code, 3);
4322 g = string_catn(g, US"-PRDR\r\n", 7);
4327 if ( accept_8bitmime
4328 && verify_check_host(&smtputf8_advertise_hosts) != FAIL)
4330 g = string_catn(g, smtp_code, 3);
4331 g = string_catn(g, US"-SMTPUTF8\r\n", 11);
4332 smtputf8_advertised = TRUE;
4336 /* Finish off the multiline reply with one that is always available. */
4338 g = string_catn(g, smtp_code, 3);
4339 g = string_catn(g, US" HELP\r\n", 7);
4342 /* Terminate the string (for debug), write it, and note that HELO/EHLO
4346 if (tls_in.active >= 0) (void)tls_write(TRUE, g->s, g->ptr, FALSE); else
4350 int i = fwrite(g->s, 1, g->ptr, smtp_out); i = i; /* compiler quietening */
4356 (void) string_from_gstring(g);
4357 while ((cr = Ustrchr(g->s, '\r')) != NULL) /* lose CRs */
4358 memmove(cr, cr + 1, (g->ptr--) - (cr - g->s));
4359 debug_printf("SMTP>> %s", g->s);
4363 /* Reset the protocol and the state, abandoning any previous message. */
4365 (sender_host_address ? protocols : protocols_local)
4367 ? pextend + (sender_host_authenticated ? pauthed : 0)
4369 + (tls_in.active >= 0 ? pcrpted : 0)
4371 cancel_cutthrough_connection(TRUE, US"sent EHLO response");
4372 smtp_reset(reset_point);
4374 break; /* HELO/EHLO */
4377 /* The MAIL command requires an address as an operand. All we do
4378 here is to parse it for syntactic correctness. The form "<>" is
4379 a special case which converts into an empty string. The start/end
4380 pointers in the original are not used further for this address, as
4381 it is the canonical extracted address which is all that is kept. */
4385 smtp_mailcmd_count++; /* Count for limit and ratelimit */
4386 was_rej_mail = TRUE; /* Reset if accepted */
4387 env_mail_type_t * mail_args; /* Sanity check & validate args */
4389 if (helo_required && !helo_seen)
4391 smtp_printf("503 HELO or EHLO required\r\n", FALSE);
4392 log_write(0, LOG_MAIN|LOG_REJECT, "rejected MAIL from %s: no "
4393 "HELO/EHLO given", host_and_ident(FALSE));
4397 if (sender_address != NULL)
4399 done = synprot_error(L_smtp_protocol_error, 503, NULL,
4400 US"sender already given");
4404 if (smtp_cmd_data[0] == 0)
4406 done = synprot_error(L_smtp_protocol_error, 501, NULL,
4407 US"MAIL must have an address operand");
4411 /* Check to see if the limit for messages per connection would be
4412 exceeded by accepting further messages. */
4414 if (smtp_accept_max_per_connection > 0 &&
4415 smtp_mailcmd_count > smtp_accept_max_per_connection)
4417 smtp_printf("421 too many messages in this connection\r\n", FALSE);
4418 log_write(0, LOG_MAIN|LOG_REJECT, "rejected MAIL command %s: too many "
4419 "messages in one connection", host_and_ident(TRUE));
4423 /* Reset for start of message - even if this is going to fail, we
4424 obviously need to throw away any previous data. */
4426 cancel_cutthrough_connection(TRUE, US"MAIL received");
4427 smtp_reset(reset_point);
4429 sender_data = recipient_data = NULL;
4431 /* Loop, checking for ESMTP additions to the MAIL FROM command. */
4435 uschar *name, *value, *end;
4436 unsigned long int size;
4437 BOOL arg_error = FALSE;
4439 if (!extract_option(&name, &value)) break;
4441 for (mail_args = env_mail_type_list;
4442 mail_args->value != ENV_MAIL_OPT_NULL;
4445 if (strcmpic(name, mail_args->name) == 0)
4447 if (mail_args->need_value && strcmpic(value, US"") == 0)
4450 switch(mail_args->value)
4452 /* Handle SIZE= by reading the value. We don't do the check till later,
4453 in order to be able to log the sender address on failure. */
4454 case ENV_MAIL_OPT_SIZE:
4455 if (((size = Ustrtoul(value, &end, 10)), *end == 0))
4457 if ((size == ULONG_MAX && errno == ERANGE) || size > INT_MAX)
4459 message_size = (int)size;
4465 /* If this session was initiated with EHLO and accept_8bitmime is set,
4466 Exim will have indicated that it supports the BODY=8BITMIME option. In
4467 fact, it does not support this according to the RFCs, in that it does not
4468 take any special action for forwarding messages containing 8-bit
4469 characters. That is why accept_8bitmime is not the default setting, but
4470 some sites want the action that is provided. We recognize both "8BITMIME"
4471 and "7BIT" as body types, but take no action. */
4472 case ENV_MAIL_OPT_BODY:
4473 if (accept_8bitmime) {
4474 if (strcmpic(value, US"8BITMIME") == 0)
4476 else if (strcmpic(value, US"7BIT") == 0)
4481 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4482 US"invalid data for BODY");
4485 DEBUG(D_receive) debug_printf("8BITMIME: %d\n", body_8bitmime);
4491 /* Handle the two DSN options, but only if configured to do so (which
4492 will have caused "DSN" to be given in the EHLO response). The code itself
4493 is included only if configured in at build time. */
4495 case ENV_MAIL_OPT_RET:
4498 /* Check if RET has already been set */
4501 synprot_error(L_smtp_syntax_error, 501, NULL,
4502 US"RET can be specified once only");
4505 dsn_ret = strcmpic(value, US"HDRS") == 0
4507 : strcmpic(value, US"FULL") == 0
4510 DEBUG(D_receive) debug_printf("DSN_RET: %d\n", dsn_ret);
4511 /* Check for invalid invalid value, and exit with error */
4514 synprot_error(L_smtp_syntax_error, 501, NULL,
4515 US"Value for RET is invalid");
4520 case ENV_MAIL_OPT_ENVID:
4523 /* Check if the dsn envid has been already set */
4524 if (dsn_envid != NULL)
4526 synprot_error(L_smtp_syntax_error, 501, NULL,
4527 US"ENVID can be specified once only");
4530 dsn_envid = string_copy(value);
4531 DEBUG(D_receive) debug_printf("DSN_ENVID: %s\n", dsn_envid);
4535 /* Handle the AUTH extension. If the value given is not "<>" and either
4536 the ACL says "yes" or there is no ACL but the sending host is
4537 authenticated, we set it up as the authenticated sender. However, if the
4538 authenticator set a condition to be tested, we ignore AUTH on MAIL unless
4539 the condition is met. The value of AUTH is an xtext, which means that +,
4540 = and cntrl chars are coded in hex; however "<>" is unaffected by this
4542 case ENV_MAIL_OPT_AUTH:
4543 if (Ustrcmp(value, "<>") != 0)
4548 if (auth_xtextdecode(value, &authenticated_sender) < 0)
4550 /* Put back terminator overrides for error message */
4553 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4554 US"invalid data for AUTH");
4557 if (!acl_smtp_mailauth)
4559 ignore_msg = US"client not authenticated";
4560 rc = sender_host_authenticated ? OK : FAIL;
4564 ignore_msg = US"rejected by ACL";
4565 rc = acl_check(ACL_WHERE_MAILAUTH, NULL, acl_smtp_mailauth,
4566 &user_msg, &log_msg);
4572 if (authenticated_by == NULL ||
4573 authenticated_by->mail_auth_condition == NULL ||
4574 expand_check_condition(authenticated_by->mail_auth_condition,
4575 authenticated_by->name, US"authenticator"))
4576 break; /* Accept the AUTH */
4578 ignore_msg = US"server_mail_auth_condition failed";
4579 if (authenticated_id != NULL)
4580 ignore_msg = string_sprintf("%s: authenticated ID=\"%s\"",
4581 ignore_msg, authenticated_id);
4586 authenticated_sender = NULL;
4587 log_write(0, LOG_MAIN, "ignoring AUTH=%s from %s (%s)",
4588 value, host_and_ident(TRUE), ignore_msg);
4591 /* Should only get DEFER or ERROR here. Put back terminator
4592 overrides for error message */
4597 (void)smtp_handle_acl_fail(ACL_WHERE_MAILAUTH, rc, user_msg,
4604 #ifndef DISABLE_PRDR
4605 case ENV_MAIL_OPT_PRDR:
4607 prdr_requested = TRUE;
4612 case ENV_MAIL_OPT_UTF8:
4613 if (smtputf8_advertised)
4615 int old_pool = store_pool;
4617 DEBUG(D_receive) debug_printf("smtputf8 requested\n");
4618 message_smtputf8 = allow_utf8_domains = TRUE;
4619 store_pool = POOL_PERM;
4620 received_protocol = string_sprintf("utf8%s", received_protocol);
4621 store_pool = old_pool;
4625 /* No valid option. Stick back the terminator characters and break
4626 the loop. Do the name-terminator second as extract_option sets
4627 value==name when it found no equal-sign.
4628 An error for a malformed address will occur. */
4629 case ENV_MAIL_OPT_NULL:
4637 /* Break out of for loop if switch() had bad argument or
4638 when start of the email address is reached */
4639 if (arg_error) break;
4642 /* If we have passed the threshold for rate limiting, apply the current
4643 delay, and update it for next time, provided this is a limited host. */
4645 if (smtp_mailcmd_count > smtp_rlm_threshold &&
4646 verify_check_host(&smtp_ratelimit_hosts) == OK)
4648 DEBUG(D_receive) debug_printf("rate limit MAIL: delay %.3g sec\n",
4649 smtp_delay_mail/1000.0);
4650 millisleep((int)smtp_delay_mail);
4651 smtp_delay_mail *= smtp_rlm_factor;
4652 if (smtp_delay_mail > (double)smtp_rlm_limit)
4653 smtp_delay_mail = (double)smtp_rlm_limit;
4656 /* Now extract the address, first applying any SMTP-time rewriting. The
4657 TRUE flag allows "<>" as a sender address. */
4659 raw_sender = rewrite_existflags & rewrite_smtp
4660 ? rewrite_one(smtp_cmd_data, rewrite_smtp, NULL, FALSE, US"",
4661 global_rewrite_rules)
4665 parse_extract_address(raw_sender, &errmess, &start, &end, &sender_domain,
4670 done = synprot_error(L_smtp_syntax_error, 501, smtp_cmd_data, errmess);
4674 sender_address = raw_sender;
4676 /* If there is a configured size limit for mail, check that this message
4677 doesn't exceed it. The check is postponed to this point so that the sender
4680 if (thismessage_size_limit > 0 && message_size > thismessage_size_limit)
4682 smtp_printf("552 Message size exceeds maximum permitted\r\n", FALSE);
4683 log_write(L_size_reject,
4684 LOG_MAIN|LOG_REJECT, "rejected MAIL FROM:<%s> %s: "
4685 "message too big: size%s=%d max=%d",
4687 host_and_ident(TRUE),
4688 (message_size == INT_MAX)? ">" : "",
4690 thismessage_size_limit);
4691 sender_address = NULL;
4695 /* Check there is enough space on the disk unless configured not to.
4696 When smtp_check_spool_space is set, the check is for thismessage_size_limit
4697 plus the current message - i.e. we accept the message only if it won't
4698 reduce the space below the threshold. Add 5000 to the size to allow for
4699 overheads such as the Received: line and storing of recipients, etc.
4700 By putting the check here, even when SIZE is not given, it allow VRFY
4701 and EXPN etc. to be used when space is short. */
4703 if (!receive_check_fs(
4704 (smtp_check_spool_space && message_size >= 0)?
4705 message_size + 5000 : 0))
4707 smtp_printf("452 Space shortage, please try later\r\n", FALSE);
4708 sender_address = NULL;
4712 /* If sender_address is unqualified, reject it, unless this is a locally
4713 generated message, or the sending host or net is permitted to send
4714 unqualified addresses - typically local machines behaving as MUAs -
4715 in which case just qualify the address. The flag is set above at the start
4716 of the SMTP connection. */
4718 if (sender_domain == 0 && sender_address[0] != 0)
4720 if (allow_unqualified_sender)
4722 sender_domain = Ustrlen(sender_address) + 1;
4723 sender_address = rewrite_address_qualify(sender_address, FALSE);
4724 DEBUG(D_receive) debug_printf("unqualified address %s accepted\n",
4729 smtp_printf("501 %s: sender address must contain a domain\r\n", FALSE,
4731 log_write(L_smtp_syntax_error,
4732 LOG_MAIN|LOG_REJECT,
4733 "unqualified sender rejected: <%s> %s%s",
4735 host_and_ident(TRUE),
4737 sender_address = NULL;
4742 /* Apply an ACL check if one is defined, before responding. Afterwards,
4743 when pipelining is not advertised, do another sync check in case the ACL
4744 delayed and the client started sending in the meantime. */
4748 rc = acl_check(ACL_WHERE_MAIL, NULL, acl_smtp_mail, &user_msg, &log_msg);
4749 if (rc == OK && !pipelining_advertised && !check_sync())
4755 if (rc == OK || rc == DISCARD)
4757 BOOL more = pipeline_response();
4760 smtp_printf("%s%s%s", more, US"250 OK",
4761 #ifndef DISABLE_PRDR
4762 prdr_requested ? US", PRDR Requested" : US"",
4769 #ifndef DISABLE_PRDR
4771 user_msg = string_sprintf("%s%s", user_msg, US", PRDR Requested");
4773 smtp_user_msg(US"250", user_msg);
4775 smtp_delay_rcpt = smtp_rlr_base;
4776 recipients_discarded = (rc == DISCARD);
4777 was_rej_mail = FALSE;
4781 done = smtp_handle_acl_fail(ACL_WHERE_MAIL, rc, user_msg, log_msg);
4782 sender_address = NULL;
4787 /* The RCPT command requires an address as an operand. There may be any
4788 number of RCPT commands, specifying multiple recipients. We build them all
4789 into a data structure. The start/end values given by parse_extract_address
4790 are not used, as we keep only the extracted address. */
4795 was_rcpt = rcpt_in_progress = TRUE;
4797 /* There must be a sender address; if the sender was rejected and
4798 pipelining was advertised, we assume the client was pipelining, and do not
4799 count this as a protocol error. Reset was_rej_mail so that further RCPTs
4800 get the same treatment. */
4802 if (sender_address == NULL)
4804 if (pipelining_advertised && last_was_rej_mail)
4806 smtp_printf("503 sender not yet given\r\n", FALSE);
4807 was_rej_mail = TRUE;
4811 done = synprot_error(L_smtp_protocol_error, 503, NULL,
4812 US"sender not yet given");
4813 was_rcpt = FALSE; /* Not a valid RCPT */
4819 /* Check for an operand */
4821 if (smtp_cmd_data[0] == 0)
4823 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4824 US"RCPT must have an address operand");
4829 /* Set the DSN flags orcpt and dsn_flags from the session*/
4835 uschar *name, *value;
4837 if (!extract_option(&name, &value))
4840 if (dsn_advertised && strcmpic(name, US"ORCPT") == 0)
4842 /* Check whether orcpt has been already set */
4845 synprot_error(L_smtp_syntax_error, 501, NULL,
4846 US"ORCPT can be specified once only");
4849 orcpt = string_copy(value);
4850 DEBUG(D_receive) debug_printf("DSN orcpt: %s\n", orcpt);
4853 else if (dsn_advertised && strcmpic(name, US"NOTIFY") == 0)
4855 /* Check if the notify flags have been already set */
4858 synprot_error(L_smtp_syntax_error, 501, NULL,
4859 US"NOTIFY can be specified once only");
4862 if (strcmpic(value, US"NEVER") == 0)
4863 flags |= rf_notify_never;
4870 while (*pp != 0 && *pp != ',') pp++;
4871 if (*pp == ',') *pp++ = 0;
4872 if (strcmpic(p, US"SUCCESS") == 0)
4874 DEBUG(D_receive) debug_printf("DSN: Setting notify success\n");
4875 flags |= rf_notify_success;
4877 else if (strcmpic(p, US"FAILURE") == 0)
4879 DEBUG(D_receive) debug_printf("DSN: Setting notify failure\n");
4880 flags |= rf_notify_failure;
4882 else if (strcmpic(p, US"DELAY") == 0)
4884 DEBUG(D_receive) debug_printf("DSN: Setting notify delay\n");
4885 flags |= rf_notify_delay;
4889 /* Catch any strange values */
4890 synprot_error(L_smtp_syntax_error, 501, NULL,
4891 US"Invalid value for NOTIFY parameter");
4896 DEBUG(D_receive) debug_printf("DSN Flags: %x\n", flags);
4900 /* Unknown option. Stick back the terminator characters and break
4901 the loop. An error for a malformed address will occur. */
4905 DEBUG(D_receive) debug_printf("Invalid RCPT option: %s : %s\n", name, value);
4912 /* Apply SMTP rewriting then extract the working address. Don't allow "<>"
4913 as a recipient address */
4915 recipient = rewrite_existflags & rewrite_smtp
4916 ? rewrite_one(smtp_cmd_data, rewrite_smtp, NULL, FALSE, US"",
4917 global_rewrite_rules)
4920 if (!(recipient = parse_extract_address(recipient, &errmess, &start, &end,
4921 &recipient_domain, FALSE)))
4923 done = synprot_error(L_smtp_syntax_error, 501, smtp_cmd_data, errmess);
4928 /* If the recipient address is unqualified, reject it, unless this is a
4929 locally generated message. However, unqualified addresses are permitted
4930 from a configured list of hosts and nets - typically when behaving as
4931 MUAs rather than MTAs. Sad that SMTP is used for both types of traffic,
4932 really. The flag is set at the start of the SMTP connection.
4934 RFC 1123 talks about supporting "the reserved mailbox postmaster"; I always
4935 assumed this meant "reserved local part", but the revision of RFC 821 and
4936 friends now makes it absolutely clear that it means *mailbox*. Consequently
4937 we must always qualify this address, regardless. */
4939 if (!recipient_domain)
4940 if (!(recipient_domain = qualify_recipient(&recipient, smtp_cmd_data,
4947 /* Check maximum allowed */
4949 if (rcpt_count > recipients_max && recipients_max > 0)
4951 if (recipients_max_reject)
4954 smtp_printf("552 too many recipients\r\n", FALSE);
4956 log_write(0, LOG_MAIN|LOG_REJECT, "too many recipients: message "
4957 "rejected: sender=<%s> %s", sender_address, host_and_ident(TRUE));
4962 smtp_printf("452 too many recipients\r\n", FALSE);
4964 log_write(0, LOG_MAIN|LOG_REJECT, "too many recipients: excess "
4965 "temporarily rejected: sender=<%s> %s", sender_address,
4966 host_and_ident(TRUE));
4973 /* If we have passed the threshold for rate limiting, apply the current
4974 delay, and update it for next time, provided this is a limited host. */
4976 if (rcpt_count > smtp_rlr_threshold &&
4977 verify_check_host(&smtp_ratelimit_hosts) == OK)
4979 DEBUG(D_receive) debug_printf("rate limit RCPT: delay %.3g sec\n",
4980 smtp_delay_rcpt/1000.0);
4981 millisleep((int)smtp_delay_rcpt);
4982 smtp_delay_rcpt *= smtp_rlr_factor;
4983 if (smtp_delay_rcpt > (double)smtp_rlr_limit)
4984 smtp_delay_rcpt = (double)smtp_rlr_limit;
4987 /* If the MAIL ACL discarded all the recipients, we bypass ACL checking
4988 for them. Otherwise, check the access control list for this recipient. As
4989 there may be a delay in this, re-check for a synchronization error
4990 afterwards, unless pipelining was advertised. */
4992 if (recipients_discarded)
4995 if ( (rc = acl_check(ACL_WHERE_RCPT, recipient, acl_smtp_rcpt, &user_msg,
4997 && !pipelining_advertised && !check_sync())
5000 /* The ACL was happy */
5004 BOOL more = pipeline_response();
5007 smtp_user_msg(US"250", user_msg);
5009 smtp_printf("250 Accepted\r\n", more);
5010 receive_add_recipient(recipient, -1);
5012 /* Set the dsn flags in the recipients_list */
5013 recipients_list[recipients_count-1].orcpt = orcpt;
5014 recipients_list[recipients_count-1].dsn_flags = flags;
5016 DEBUG(D_receive) debug_printf("DSN: orcpt: %s flags: %d\n",
5017 recipients_list[recipients_count-1].orcpt,
5018 recipients_list[recipients_count-1].dsn_flags);
5021 /* The recipient was discarded */
5023 else if (rc == DISCARD)
5026 smtp_user_msg(US"250", user_msg);
5028 smtp_printf("250 Accepted\r\n", FALSE);
5031 log_write(0, LOG_MAIN|LOG_REJECT, "%s F=<%s> RCPT %s: "
5032 "discarded by %s ACL%s%s", host_and_ident(TRUE),
5033 sender_address_unrewritten? sender_address_unrewritten : sender_address,
5034 smtp_cmd_argument, recipients_discarded? "MAIL" : "RCPT",
5035 log_msg ? US": " : US"", log_msg ? log_msg : US"");
5038 /* Either the ACL failed the address, or it was deferred. */
5042 if (rc == FAIL) rcpt_fail_count++; else rcpt_defer_count++;
5043 done = smtp_handle_acl_fail(ACL_WHERE_RCPT, rc, user_msg, log_msg);
5048 /* The DATA command is legal only if it follows successful MAIL FROM
5049 and RCPT TO commands. However, if pipelining is advertised, a bad DATA is
5050 not counted as a protocol error if it follows RCPT (which must have been
5051 rejected if there are no recipients.) This function is complete when a
5052 valid DATA command is encountered.
5054 Note concerning the code used: RFC 2821 says this:
5056 - If there was no MAIL, or no RCPT, command, or all such commands
5057 were rejected, the server MAY return a "command out of sequence"
5058 (503) or "no valid recipients" (554) reply in response to the
5061 The example in the pipelining RFC 2920 uses 554, but I use 503 here
5062 because it is the same whether pipelining is in use or not.
5064 If all the RCPT commands that precede DATA provoked the same error message
5065 (often indicating some kind of system error), it is helpful to include it
5066 with the DATA rejection (an idea suggested by Tony Finch). */
5073 if (chunking_state != CHUNKING_OFFERED)
5075 done = synprot_error(L_smtp_protocol_error, 503, NULL,
5076 US"BDAT command used when CHUNKING not advertised");
5080 /* grab size, endmarker */
5082 if (sscanf(CS smtp_cmd_data, "%u %n", &chunking_datasize, &n) < 1)
5084 done = synprot_error(L_smtp_protocol_error, 501, NULL,
5085 US"missing size for BDAT command");
5088 chunking_state = strcmpic(smtp_cmd_data+n, US"LAST") == 0
5089 ? CHUNKING_LAST : CHUNKING_ACTIVE;
5090 chunking_data_left = chunking_datasize;
5091 DEBUG(D_receive) debug_printf("chunking state %d, %d bytes\n",
5092 (int)chunking_state, chunking_data_left);
5094 /* push the current receive_* function on the "stack", and
5095 replace them by bdat_getc(), which in turn will use the lwr_receive_*
5096 functions to do the dirty work. */
5097 lwr_receive_getc = receive_getc;
5098 lwr_receive_getbuf = receive_getbuf;
5099 lwr_receive_ungetc = receive_ungetc;
5101 receive_getc = bdat_getc;
5102 receive_ungetc = bdat_ungetc;
5113 DATA_BDAT: /* Common code for DATA and BDAT */
5114 if (!discarded && recipients_count <= 0)
5116 if (rcpt_smtp_response_same && rcpt_smtp_response != NULL)
5118 uschar *code = US"503";
5119 int len = Ustrlen(rcpt_smtp_response);
5120 smtp_respond(code, 3, FALSE, US"All RCPT commands were rejected with "
5122 /* Responses from smtp_printf() will have \r\n on the end */
5123 if (len > 2 && rcpt_smtp_response[len-2] == '\r')
5124 rcpt_smtp_response[len-2] = 0;
5125 smtp_respond(code, 3, FALSE, rcpt_smtp_response);
5127 if (pipelining_advertised && last_was_rcpt)
5128 smtp_printf("503 Valid RCPT command must precede %s\r\n", FALSE,
5129 smtp_names[smtp_connection_had[smtp_ch_index-1]]);
5131 done = synprot_error(L_smtp_protocol_error, 503, NULL,
5132 smtp_connection_had[smtp_ch_index-1] == SCH_DATA
5133 ? US"valid RCPT command must precede DATA"
5134 : US"valid RCPT command must precede BDAT");
5136 if (chunking_state > CHUNKING_OFFERED)
5141 if (toomany && recipients_max_reject)
5143 sender_address = NULL; /* This will allow a new MAIL without RSET */
5144 sender_address_unrewritten = NULL;
5145 smtp_printf("554 Too many recipients\r\n", FALSE);
5149 if (chunking_state > CHUNKING_OFFERED)
5150 rc = OK; /* No predata ACL or go-ahead output for BDAT */
5153 /* If there is an ACL, re-check the synchronization afterwards, since the
5154 ACL may have delayed. To handle cutthrough delivery enforce a dummy call
5155 to get the DATA command sent. */
5157 if (acl_smtp_predata == NULL && cutthrough.fd < 0)
5161 uschar * acl = acl_smtp_predata ? acl_smtp_predata : US"accept";
5162 enable_dollar_recipients = TRUE;
5163 rc = acl_check(ACL_WHERE_PREDATA, NULL, acl, &user_msg,
5165 enable_dollar_recipients = FALSE;
5166 if (rc == OK && !check_sync())
5170 { /* Either the ACL failed the address, or it was deferred. */
5171 done = smtp_handle_acl_fail(ACL_WHERE_PREDATA, rc, user_msg, log_msg);
5177 smtp_user_msg(US"354", user_msg);
5180 "354 Enter message, ending with \".\" on a line by itself\r\n", FALSE);
5184 if (smtp_in) /* all ACKs needed to ramp window up for bulk data */
5185 (void) setsockopt(fileno(smtp_in), IPPROTO_TCP, TCP_QUICKACK,
5186 US &on, sizeof(on));
5189 message_ended = END_NOTENDED; /* Indicate in middle of data */
5200 if (!(address = parse_extract_address(smtp_cmd_data, &errmess,
5201 &start, &end, &recipient_domain, FALSE)))
5203 smtp_printf("501 %s\r\n", FALSE, errmess);
5207 if (!recipient_domain)
5208 if (!(recipient_domain = qualify_recipient(&address, smtp_cmd_data,
5212 if ((rc = acl_check(ACL_WHERE_VRFY, address, acl_smtp_vrfy,
5213 &user_msg, &log_msg)) != OK)
5214 done = smtp_handle_acl_fail(ACL_WHERE_VRFY, rc, user_msg, log_msg);
5218 address_item * addr = deliver_make_addr(address, FALSE);
5220 switch(verify_address(addr, NULL, vopt_is_recipient | vopt_qualify, -1,
5221 -1, -1, NULL, NULL, NULL))
5224 s = string_sprintf("250 <%s> is deliverable", address);
5228 s = (addr->user_message != NULL)?
5229 string_sprintf("451 <%s> %s", address, addr->user_message) :
5230 string_sprintf("451 Cannot resolve <%s> at this time", address);
5234 s = (addr->user_message != NULL)?
5235 string_sprintf("550 <%s> %s", address, addr->user_message) :
5236 string_sprintf("550 <%s> is not deliverable", address);
5237 log_write(0, LOG_MAIN, "VRFY failed for %s %s",
5238 smtp_cmd_argument, host_and_ident(TRUE));
5242 smtp_printf("%s\r\n", FALSE, s);
5250 rc = acl_check(ACL_WHERE_EXPN, NULL, acl_smtp_expn, &user_msg, &log_msg);
5252 done = smtp_handle_acl_fail(ACL_WHERE_EXPN, rc, user_msg, log_msg);
5255 BOOL save_log_testing_mode = log_testing_mode;
5256 address_test_mode = log_testing_mode = TRUE;
5257 (void) verify_address(deliver_make_addr(smtp_cmd_data, FALSE),
5258 smtp_out, vopt_is_recipient | vopt_qualify | vopt_expn, -1, -1, -1,
5260 address_test_mode = FALSE;
5261 log_testing_mode = save_log_testing_mode; /* true for -bh */
5270 if (!tls_advertised)
5272 done = synprot_error(L_smtp_protocol_error, 503, NULL,
5273 US"STARTTLS command used when not advertised");
5277 /* Apply an ACL check if one is defined */
5279 if ( acl_smtp_starttls
5280 && (rc = acl_check(ACL_WHERE_STARTTLS, NULL, acl_smtp_starttls,
5281 &user_msg, &log_msg)) != OK
5284 done = smtp_handle_acl_fail(ACL_WHERE_STARTTLS, rc, user_msg, log_msg);
5288 /* RFC 2487 is not clear on when this command may be sent, though it
5289 does state that all information previously obtained from the client
5290 must be discarded if a TLS session is started. It seems reasonable to
5291 do an implied RSET when STARTTLS is received. */
5293 incomplete_transaction_log(US"STARTTLS");
5294 cancel_cutthrough_connection(TRUE, US"STARTTLS received");
5295 smtp_reset(reset_point);
5297 cmd_list[CMD_LIST_STARTTLS].is_mail_cmd = FALSE;
5299 /* There's an attack where more data is read in past the STARTTLS command
5300 before TLS is negotiated, then assumed to be part of the secure session
5301 when used afterwards; we use segregated input buffers, so are not
5302 vulnerable, but we want to note when it happens and, for sheer paranoia,
5303 ensure that the buffer is "wiped".
5304 Pipelining sync checks will normally have protected us too, unless disabled
5305 by configuration. */
5307 if (receive_smtp_buffered())
5310 debug_printf("Non-empty input buffer after STARTTLS; naive attack?\n");
5311 if (tls_in.active < 0)
5312 smtp_inend = smtp_inptr = smtp_inbuffer;
5313 /* and if TLS is already active, tls_server_start() should fail */
5316 /* There is nothing we value in the input buffer and if TLS is successfully
5317 negotiated, we won't use this buffer again; if TLS fails, we'll just read
5318 fresh content into it. The buffer contains arbitrary content from an
5319 untrusted remote source; eg: NOOP <shellcode>\r\nSTARTTLS\r\n
5320 It seems safest to just wipe away the content rather than leave it as a
5321 target to jump to. */
5323 memset(smtp_inbuffer, 0, IN_BUFFER_SIZE);
5325 /* Attempt to start up a TLS session, and if successful, discard all
5326 knowledge that was obtained previously. At least, that's what the RFC says,
5327 and that's what happens by default. However, in order to work round YAEB,
5328 there is an option to remember the esmtp state. Sigh.
5330 We must allow for an extra EHLO command and an extra AUTH command after
5331 STARTTLS that don't add to the nonmail command count. */
5334 if ((rc = tls_server_start(tls_require_ciphers, &s)) == OK)
5336 if (!tls_remember_esmtp)
5337 helo_seen = esmtp = auth_advertised = pipelining_advertised = FALSE;
5338 cmd_list[CMD_LIST_EHLO].is_mail_cmd = TRUE;
5339 cmd_list[CMD_LIST_AUTH].is_mail_cmd = TRUE;
5340 cmd_list[CMD_LIST_TLS_AUTH].is_mail_cmd = TRUE;
5341 if (sender_helo_name)
5343 store_free(sender_helo_name);
5344 sender_helo_name = NULL;
5345 host_build_sender_fullhost(); /* Rebuild */
5346 set_process_info("handling incoming TLS connection from %s",
5347 host_and_ident(FALSE));
5350 (sender_host_address ? protocols : protocols_local)
5352 ? pextend + (sender_host_authenticated ? pauthed : 0)
5354 + (tls_in.active >= 0 ? pcrpted : 0)
5357 sender_host_auth_pubname = sender_host_authenticated = NULL;
5358 authenticated_id = NULL;
5359 sync_cmd_limit = NON_SYNC_CMD_NON_PIPELINING;
5360 DEBUG(D_tls) debug_printf("TLS active\n");
5361 break; /* Successful STARTTLS */
5364 (void) smtp_log_tls_fail(s);
5366 /* Some local configuration problem was discovered before actually trying
5367 to do a TLS handshake; give a temporary error. */
5371 smtp_printf("454 TLS currently unavailable\r\n", FALSE);
5375 /* Hard failure. Reject everything except QUIT or closed connection. One
5376 cause for failure is a nested STARTTLS, in which case tls_in.active remains
5377 set, but we must still reject all incoming commands. */
5379 DEBUG(D_tls) debug_printf("TLS failed to start\n");
5380 while (done <= 0) switch(smtp_read_command(FALSE, GETC_BUFFER_UNLIMITED))
5383 log_write(L_smtp_connection, LOG_MAIN, "%s closed by EOF",
5384 smtp_get_connection_info());
5385 smtp_notquit_exit(US"tls-failed", NULL, NULL);
5389 /* It is perhaps arguable as to which exit ACL should be called here,
5390 but as it is probably a situation that almost never arises, it
5391 probably doesn't matter. We choose to call the real QUIT ACL, which in
5392 some sense is perhaps "right". */
5397 && ((rc = acl_check(ACL_WHERE_QUIT, NULL, acl_smtp_quit, &user_msg,
5398 &log_msg)) == ERROR))
5399 log_write(0, LOG_MAIN|LOG_PANIC, "ACL for QUIT returned ERROR: %s",
5402 smtp_respond(US"221", 3, TRUE, user_msg);
5404 smtp_printf("221 %s closing connection\r\n", FALSE, smtp_active_hostname);
5405 log_write(L_smtp_connection, LOG_MAIN, "%s closed by QUIT",
5406 smtp_get_connection_info());
5411 smtp_printf("554 Security failure\r\n", FALSE);
5414 tls_close(TRUE, TLS_SHUTDOWN_NOWAIT);
5419 /* The ACL for QUIT is provided for gathering statistical information or
5420 similar; it does not affect the response code, but it can supply a custom
5424 smtp_quit_handler(&user_msg, &log_msg);
5430 smtp_rset_handler();
5431 cancel_cutthrough_connection(TRUE, US"RSET received");
5432 smtp_reset(reset_point);
5439 smtp_printf("250 OK\r\n", FALSE);
5443 /* Show ETRN/EXPN/VRFY if there's an ACL for checking hosts; if actually
5444 used, a check will be done for permitted hosts. Show STARTTLS only if not
5445 already in a TLS session and if it would be advertised in the EHLO
5450 smtp_printf("214-Commands supported:\r\n", TRUE);
5454 Ustrcat(buffer, " AUTH");
5456 if (tls_in.active < 0 &&
5457 verify_check_host(&tls_advertise_hosts) != FAIL)
5458 Ustrcat(buffer, " STARTTLS");
5460 Ustrcat(buffer, " HELO EHLO MAIL RCPT DATA BDAT");
5461 Ustrcat(buffer, " NOOP QUIT RSET HELP");
5462 if (acl_smtp_etrn != NULL) Ustrcat(buffer, " ETRN");
5463 if (acl_smtp_expn != NULL) Ustrcat(buffer, " EXPN");
5464 if (acl_smtp_vrfy != NULL) Ustrcat(buffer, " VRFY");
5465 smtp_printf("214%s\r\n", FALSE, buffer);
5471 incomplete_transaction_log(US"connection lost");
5472 smtp_notquit_exit(US"connection-lost", US"421",
5473 US"%s lost input connection", smtp_active_hostname);
5475 /* Don't log by default unless in the middle of a message, as some mailers
5476 just drop the call rather than sending QUIT, and it clutters up the logs.
5479 if (sender_address || recipients_count > 0)
5480 log_write(L_lost_incoming_connection, LOG_MAIN,
5481 "unexpected %s while reading SMTP command from %s%s%s D=%s",
5482 sender_host_unknown ? "EOF" : "disconnection",
5483 tcp_in_fastopen && !tcp_in_fastopen_logged ? US"TFO " : US"",
5484 host_and_ident(FALSE), smtp_read_error,
5485 string_timesince(&smtp_connection_start)
5489 log_write(L_smtp_connection, LOG_MAIN, "%s %slost%s D=%s",
5490 smtp_get_connection_info(),
5491 tcp_in_fastopen && !tcp_in_fastopen_logged ? US"TFO " : US"",
5493 string_timesince(&smtp_connection_start)
5504 done = synprot_error(L_smtp_protocol_error, 503, NULL,
5505 US"ETRN is not permitted inside a transaction");
5509 log_write(L_etrn, LOG_MAIN, "ETRN %s received from %s", smtp_cmd_argument,
5510 host_and_ident(FALSE));
5512 if ((rc = acl_check(ACL_WHERE_ETRN, NULL, acl_smtp_etrn,
5513 &user_msg, &log_msg)) != OK)
5515 done = smtp_handle_acl_fail(ACL_WHERE_ETRN, rc, user_msg, log_msg);
5519 /* Compute the serialization key for this command. */
5521 etrn_serialize_key = string_sprintf("etrn-%s\n", smtp_cmd_data);
5523 /* If a command has been specified for running as a result of ETRN, we
5524 permit any argument to ETRN. If not, only the # standard form is permitted,
5525 since that is strictly the only kind of ETRN that can be implemented
5526 according to the RFC. */
5528 if (smtp_etrn_command)
5532 etrn_command = smtp_etrn_command;
5533 deliver_domain = smtp_cmd_data;
5534 rc = transport_set_up_command(&argv, smtp_etrn_command, TRUE, 0, NULL,
5535 US"ETRN processing", &error);
5536 deliver_domain = NULL;
5539 log_write(0, LOG_MAIN|LOG_PANIC, "failed to set up ETRN command: %s",
5541 smtp_printf("458 Internal failure\r\n", FALSE);
5546 /* Else set up to call Exim with the -R option. */
5550 if (*smtp_cmd_data++ != '#')
5552 done = synprot_error(L_smtp_syntax_error, 501, NULL,
5553 US"argument must begin with #");
5556 etrn_command = US"exim -R";
5557 argv = CUSS child_exec_exim(CEE_RETURN_ARGV, TRUE, NULL, TRUE,
5558 *queue_name ? 4 : 2,
5559 US"-R", smtp_cmd_data,
5560 US"-MCG", queue_name);
5563 /* If we are host-testing, don't actually do anything. */
5569 debug_printf("ETRN command is: %s\n", etrn_command);
5570 debug_printf("ETRN command execution skipped\n");
5572 if (user_msg == NULL) smtp_printf("250 OK\r\n", FALSE);
5573 else smtp_user_msg(US"250", user_msg);
5578 /* If ETRN queue runs are to be serialized, check the database to
5579 ensure one isn't already running. */
5581 if (smtp_etrn_serialize && !enq_start(etrn_serialize_key, 1))
5583 smtp_printf("458 Already processing %s\r\n", FALSE, smtp_cmd_data);
5587 /* Fork a child process and run the command. We don't want to have to
5588 wait for the process at any point, so set SIGCHLD to SIG_IGN before
5589 forking. It should be set that way anyway for external incoming SMTP,
5590 but we save and restore to be tidy. If serialization is required, we
5591 actually run the command in yet another process, so we can wait for it
5592 to complete and then remove the serialization lock. */
5594 oldsignal = signal(SIGCHLD, SIG_IGN);
5596 if ((pid = fork()) == 0)
5598 smtp_input = FALSE; /* This process is not associated with the */
5599 (void)fclose(smtp_in); /* SMTP call any more. */
5600 (void)fclose(smtp_out);
5602 signal(SIGCHLD, SIG_DFL); /* Want to catch child */
5604 /* If not serializing, do the exec right away. Otherwise, fork down
5605 into another process. */
5607 if (!smtp_etrn_serialize || (pid = fork()) == 0)
5609 DEBUG(D_exec) debug_print_argv(argv);
5610 exim_nullstd(); /* Ensure std{in,out,err} exist */
5611 execv(CS argv[0], (char *const *)argv);
5612 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "exec of \"%s\" (ETRN) failed: %s",
5613 etrn_command, strerror(errno));
5614 _exit(EXIT_FAILURE); /* paranoia */
5617 /* Obey this if smtp_serialize and the 2nd fork yielded non-zero. That
5618 is, we are in the first subprocess, after forking again. All we can do
5619 for a failing fork is to log it. Otherwise, wait for the 2nd process to
5620 complete, before removing the serialization. */
5623 log_write(0, LOG_MAIN|LOG_PANIC, "2nd fork for serialized ETRN "
5624 "failed: %s", strerror(errno));
5628 DEBUG(D_any) debug_printf("waiting for serialized ETRN process %d\n",
5630 (void)wait(&status);
5631 DEBUG(D_any) debug_printf("serialized ETRN process %d ended\n",
5635 enq_end(etrn_serialize_key);
5636 _exit(EXIT_SUCCESS);
5639 /* Back in the top level SMTP process. Check that we started a subprocess
5640 and restore the signal state. */
5644 log_write(0, LOG_MAIN|LOG_PANIC, "fork of process for ETRN failed: %s",
5646 smtp_printf("458 Unable to fork process\r\n", FALSE);
5647 if (smtp_etrn_serialize) enq_end(etrn_serialize_key);
5651 if (user_msg == NULL) smtp_printf("250 OK\r\n", FALSE);
5652 else smtp_user_msg(US"250", user_msg);
5655 signal(SIGCHLD, oldsignal);
5660 done = synprot_error(L_smtp_syntax_error, 501, NULL,
5661 US"unexpected argument data");
5665 /* This currently happens only for NULLs, but could be extended. */
5668 done = synprot_error(L_smtp_syntax_error, 0, NULL, /* Just logs */
5669 US"NULL character(s) present (shown as '?')");
5670 smtp_printf("501 NULL characters are not allowed in SMTP commands\r\n", FALSE);
5676 if (smtp_inend >= smtp_inbuffer + IN_BUFFER_SIZE)
5677 smtp_inend = smtp_inbuffer + IN_BUFFER_SIZE - 1;
5678 c = smtp_inend - smtp_inptr;
5679 if (c > 150) c = 150;
5681 incomplete_transaction_log(US"sync failure");
5682 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP protocol synchronization error "
5683 "(next input sent too soon: pipelining was%s advertised): "
5684 "rejected \"%s\" %s next input=\"%s\"",
5685 pipelining_advertised? "" : " not",
5686 smtp_cmd_buffer, host_and_ident(TRUE),
5687 string_printing(smtp_inptr));
5688 smtp_notquit_exit(US"synchronization-error", US"554",
5689 US"SMTP synchronization error");
5690 done = 1; /* Pretend eof - drops connection */
5694 case TOO_MANY_NONMAIL_CMD:
5695 s = smtp_cmd_buffer;
5696 while (*s != 0 && !isspace(*s)) s++;
5697 incomplete_transaction_log(US"too many non-mail commands");
5698 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
5699 "nonmail commands (last was \"%.*s\")", host_and_ident(FALSE),
5700 (int)(s - smtp_cmd_buffer), smtp_cmd_buffer);
5701 smtp_notquit_exit(US"bad-commands", US"554", US"Too many nonmail commands");
5702 done = 1; /* Pretend eof - drops connection */
5705 #ifdef SUPPORT_PROXY
5706 case PROXY_FAIL_IGNORE_CMD:
5707 smtp_printf("503 Command refused, required Proxy negotiation failed\r\n", FALSE);
5712 if (unknown_command_count++ >= smtp_max_unknown_commands)
5714 log_write(L_smtp_syntax_error, LOG_MAIN,
5715 "SMTP syntax error in \"%s\" %s %s",
5716 string_printing(smtp_cmd_buffer), host_and_ident(TRUE),
5717 US"unrecognized command");
5718 incomplete_transaction_log(US"unrecognized command");
5719 smtp_notquit_exit(US"bad-commands", US"500",
5720 US"Too many unrecognized commands");
5722 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
5723 "unrecognized commands (last was \"%s\")", host_and_ident(FALSE),
5724 string_printing(smtp_cmd_buffer));
5727 done = synprot_error(L_smtp_syntax_error, 500, NULL,
5728 US"unrecognized command");
5732 /* This label is used by goto's inside loops that want to break out to
5733 the end of the command-processing loop. */
5736 last_was_rej_mail = was_rej_mail; /* Remember some last commands for */
5737 last_was_rcpt = was_rcpt; /* protocol error handling */
5741 return done - 2; /* Convert yield values */
5747 authres_smtpauth(gstring * g)
5749 if (!sender_host_authenticated)
5752 g = string_append(g, 2, US";\n\tauth=pass (", sender_host_auth_pubname);
5754 if (Ustrcmp(sender_host_auth_pubname, "tls") != 0)
5755 g = string_append(g, 2, US") smtp.auth=", authenticated_id);
5756 else if (authenticated_id)
5757 g = string_append(g, 2, US") x509.auth=", authenticated_id);
5759 g = string_catn(g, US") reason=x509.auth", 17);
5761 if (authenticated_sender)
5762 g = string_append(g, 2, US" smtp.mailfrom=", authenticated_sender);
5770 /* End of smtp_in.c */