1 /*************************************************
2 * Exim - an Internet mail transport agent *
3 *************************************************/
5 /* Copyright (c) The Exim Maintainers 2020 - 2022 */
6 /* Copyright (c) University of Cambridge 1995 - 2018 */
7 /* See the file NOTICE for conditions of use and distribution. */
8 /* SPDX-License-Identifier: GPL-2.0-or-later */
10 /* Functions for handling an incoming SMTP call. */
17 /* Initialize for TCP wrappers if so configured. It appears that the macro
18 HAVE_IPV6 is used in some versions of the tcpd.h header, so we unset it before
19 including that header, and restore its value afterwards. */
21 #ifdef USE_TCP_WRAPPERS
24 #define EXIM_HAVE_IPV6
30 #define HAVE_IPV6 TRUE
33 int allow_severity = LOG_INFO;
34 int deny_severity = LOG_NOTICE;
35 uschar *tcp_wrappers_name;
39 /* Size of buffer for reading SMTP commands. We used to use 512, as defined
40 by RFC 821. However, RFC 1869 specifies that this must be increased for SMTP
41 commands that accept arguments, and this in particular applies to AUTH, where
42 the data can be quite long. More recently this value was 2048 in Exim;
43 however, RFC 4954 (circa 2007) recommends 12288 bytes to handle AUTH. Clients
44 such as Thunderbird will send an AUTH with an initial-response for GSSAPI.
45 The maximum size of a Kerberos ticket under Windows 2003 is 12000 bytes, and
46 we need room to handle large base64-encoded AUTHs for GSSAPI.
49 #define SMTP_CMD_BUFFER_SIZE 16384
51 /* Size of buffer for reading SMTP incoming packets */
53 #define IN_BUFFER_SIZE 8192
55 /* Structure for SMTP command list */
62 short int is_mail_cmd;
65 /* Codes for identifying commands. We order them so that those that come first
66 are those for which synchronization is always required. Checking this can help
70 /* These commands are required to be synchronized, i.e. to be the last in a
71 block of commands when pipelining. */
73 HELO_CMD, EHLO_CMD, DATA_CMD, /* These are listed in the pipelining */
74 VRFY_CMD, EXPN_CMD, NOOP_CMD, /* RFC as requiring synchronization */
75 ETRN_CMD, /* This by analogy with TURN from the RFC */
76 STARTTLS_CMD, /* Required by the STARTTLS RFC */
77 TLS_AUTH_CMD, /* auto-command at start of SSL */
79 /* This is a dummy to identify the non-sync commands when pipelining */
81 NON_SYNC_CMD_PIPELINING,
83 /* These commands need not be synchronized when pipelining */
85 MAIL_CMD, RCPT_CMD, RSET_CMD,
87 /* This is a dummy to identify the non-sync commands when not pipelining */
89 NON_SYNC_CMD_NON_PIPELINING,
91 /* RFC3030 section 2: "After all MAIL and RCPT responses are collected and
92 processed the message is sent using a series of BDAT commands"
93 implies that BDAT should be synchronized. However, we see Google, at least,
94 sending MAIL,RCPT,BDAT-LAST in a single packet, clearly not waiting for
95 processing of the RCPT response(s). We shall do the same, and not require
96 synch for BDAT. Worse, as the chunk may (very likely will) follow the
97 command-header in the same packet we cannot do the usual "is there any
98 follow-on data after the command line" even for non-pipeline mode.
99 So we'll need an explicit check after reading the expected chunk amount
100 when non-pipe, before sending the ACK. */
104 /* I have been unable to find a statement about the use of pipelining
105 with AUTH, so to be on the safe side it is here, though I kind of feel
106 it should be up there with the synchronized commands. */
110 /* I'm not sure about these, but I don't think they matter. */
115 PROXY_FAIL_IGNORE_CMD,
118 /* These are specials that don't correspond to actual commands */
120 EOF_CMD, OTHER_CMD, BADARG_CMD, BADCHAR_CMD, BADSYN_CMD,
121 TOO_MANY_NONMAIL_CMD };
124 /* This is a convenience macro for adding the identity of an SMTP command
125 to the circular buffer that holds a list of the last n received. */
128 smtp_connection_had[smtp_ch_index++] = n; \
129 if (smtp_ch_index >= SMTP_HBUFF_SIZE) smtp_ch_index = 0
132 /*************************************************
133 * Local static variables *
134 *************************************************/
137 BOOL auth_advertised :1;
139 BOOL tls_advertised :1;
141 BOOL dsn_advertised :1;
143 BOOL helo_verify_required :1;
146 BOOL helo_accept_junk :1;
147 #ifndef DISABLE_PIPE_CONNECT
148 BOOL pipe_connect_acceptable :1;
150 BOOL rcpt_smtp_response_same :1;
151 BOOL rcpt_in_progress :1;
152 BOOL smtp_exit_function_called :1;
154 BOOL smtputf8_advertised :1;
157 .helo_verify_required = FALSE,
158 .helo_verify = FALSE,
159 .smtp_exit_function_called = FALSE,
162 static auth_instance *authenticated_by;
163 static int count_nonmail;
164 static int nonmail_command_count;
165 static int synprot_error_count;
166 static int unknown_command_count;
167 static int sync_cmd_limit;
168 static int smtp_write_error = 0;
170 static uschar *rcpt_smtp_response;
171 static uschar *smtp_data_buffer;
172 static uschar *smtp_cmd_data;
174 /* We need to know the position of RSET, HELO, EHLO, AUTH, and STARTTLS. Their
175 final fields of all except AUTH are forced TRUE at the start of a new message
176 setup, to allow one of each between messages that is not counted as a nonmail
177 command. (In fact, only one of HELO/EHLO is not counted.) Also, we have to
178 allow a new EHLO after starting up TLS.
180 AUTH is "falsely" labelled as a mail command initially, so that it doesn't get
181 counted. However, the flag is changed when AUTH is received, so that multiple
182 failing AUTHs will eventually hit the limit. After a successful AUTH, another
183 AUTH is already forbidden. After a TLS session is started, AUTH's flag is again
184 forced TRUE, to allow for the re-authentication that can happen at that point.
186 QUIT is also "falsely" labelled as a mail command so that it doesn't up the
187 count of non-mail commands and possibly provoke an error.
189 tls_auth is a pseudo-command, never expected in input. It is activated
190 on TLS startup and looks for a tls authenticator. */
192 static smtp_cmd_list cmd_list[] = {
193 /* name len cmd has_arg is_mail_cmd */
195 { "rset", sizeof("rset")-1, RSET_CMD, FALSE, FALSE }, /* First */
196 { "helo", sizeof("helo")-1, HELO_CMD, TRUE, FALSE },
197 { "ehlo", sizeof("ehlo")-1, EHLO_CMD, TRUE, FALSE },
198 { "auth", sizeof("auth")-1, AUTH_CMD, TRUE, TRUE },
200 { "starttls", sizeof("starttls")-1, STARTTLS_CMD, FALSE, FALSE },
201 { "tls_auth", 0, TLS_AUTH_CMD, FALSE, FALSE },
204 /* If you change anything above here, also fix the definitions below. */
206 { "mail from:", sizeof("mail from:")-1, MAIL_CMD, TRUE, TRUE },
207 { "rcpt to:", sizeof("rcpt to:")-1, RCPT_CMD, TRUE, TRUE },
208 { "data", sizeof("data")-1, DATA_CMD, FALSE, TRUE },
209 { "bdat", sizeof("bdat")-1, BDAT_CMD, TRUE, TRUE },
210 { "quit", sizeof("quit")-1, QUIT_CMD, FALSE, TRUE },
211 { "noop", sizeof("noop")-1, NOOP_CMD, TRUE, FALSE },
212 { "etrn", sizeof("etrn")-1, ETRN_CMD, TRUE, FALSE },
213 { "vrfy", sizeof("vrfy")-1, VRFY_CMD, TRUE, FALSE },
214 { "expn", sizeof("expn")-1, EXPN_CMD, TRUE, FALSE },
215 { "help", sizeof("help")-1, HELP_CMD, TRUE, FALSE }
218 static smtp_cmd_list *cmd_list_end =
219 cmd_list + sizeof(cmd_list)/sizeof(smtp_cmd_list);
221 #define CMD_LIST_RSET 0
222 #define CMD_LIST_HELO 1
223 #define CMD_LIST_EHLO 2
224 #define CMD_LIST_AUTH 3
225 #define CMD_LIST_STARTTLS 4
226 #define CMD_LIST_TLS_AUTH 5
228 /* This list of names is used for performing the smtp_no_mail logging action.
229 It must be kept in step with the SCH_xxx enumerations. */
231 uschar * smtp_names[] =
233 US"NONE", US"AUTH", US"DATA", US"BDAT", US"EHLO", US"ETRN", US"EXPN",
234 US"HELO", US"HELP", US"MAIL", US"NOOP", US"QUIT", US"RCPT", US"RSET",
235 US"STARTTLS", US"VRFY" };
237 static uschar *protocols_local[] = {
238 US"local-smtp", /* HELO */
239 US"local-smtps", /* The rare case EHLO->STARTTLS->HELO */
240 US"local-esmtp", /* EHLO */
241 US"local-esmtps", /* EHLO->STARTTLS->EHLO */
242 US"local-esmtpa", /* EHLO->AUTH */
243 US"local-esmtpsa" /* EHLO->STARTTLS->EHLO->AUTH */
245 static uschar *protocols[] = {
247 US"smtps", /* The rare case EHLO->STARTTLS->HELO */
248 US"esmtp", /* EHLO */
249 US"esmtps", /* EHLO->STARTTLS->EHLO */
250 US"esmtpa", /* EHLO->AUTH */
251 US"esmtpsa" /* EHLO->STARTTLS->EHLO->AUTH */
256 #define pcrpted 1 /* added to pextend or pnormal */
257 #define pauthed 2 /* added to pextend */
259 /* Sanity check and validate optional args to MAIL FROM: envelope */
262 ENV_MAIL_OPT_SIZE, ENV_MAIL_OPT_BODY, ENV_MAIL_OPT_AUTH,
266 ENV_MAIL_OPT_RET, ENV_MAIL_OPT_ENVID,
272 uschar * name; /* option requested during MAIL cmd */
273 int value; /* enum type */
274 BOOL need_value; /* TRUE requires value (name=value pair format)
275 FALSE is a singleton */
277 static env_mail_type_t env_mail_type_list[] = {
278 { US"SIZE", ENV_MAIL_OPT_SIZE, TRUE },
279 { US"BODY", ENV_MAIL_OPT_BODY, TRUE },
280 { US"AUTH", ENV_MAIL_OPT_AUTH, TRUE },
282 { US"PRDR", ENV_MAIL_OPT_PRDR, FALSE },
284 { US"RET", ENV_MAIL_OPT_RET, TRUE },
285 { US"ENVID", ENV_MAIL_OPT_ENVID, TRUE },
287 { US"SMTPUTF8",ENV_MAIL_OPT_UTF8, FALSE }, /* rfc6531 */
289 /* keep this the last entry */
290 { US"NULL", ENV_MAIL_OPT_NULL, FALSE },
293 /* When reading SMTP from a remote host, we have to use our own versions of the
294 C input-reading functions, in order to be able to flush the SMTP output only
295 when about to read more data from the socket. This is the only way to get
296 optimal performance when the client is using pipelining. Flushing for every
297 command causes a separate packet and reply packet each time; saving all the
298 responses up (when pipelining) combines them into one packet and one response.
300 For simplicity, these functions are used for *all* SMTP input, not only when
301 receiving over a socket. However, after setting up a secure socket (SSL), input
302 is read via the OpenSSL library, and another set of functions is used instead
305 These functions are set in the receive_getc etc. variables and called with the
306 same interface as the C functions. However, since there can only ever be
307 one incoming SMTP call, we just use a single buffer and flags. There is no need
308 to implement a complicated private FILE-like structure.*/
310 static uschar *smtp_inbuffer;
311 static uschar *smtp_inptr;
312 static uschar *smtp_inend;
313 static int smtp_had_eof;
314 static int smtp_had_error;
317 /* forward declarations */
318 static int smtp_read_command(BOOL check_sync, unsigned buffer_lim);
319 static int synprot_error(int type, int code, uschar *data, uschar *errmess);
320 static void smtp_quit_handler(uschar **, uschar **);
321 static void smtp_rset_handler(void);
323 /*************************************************
324 * Log incomplete transactions *
325 *************************************************/
327 /* This function is called after a transaction has been aborted by RSET, QUIT,
328 connection drops or other errors. It logs the envelope information received
329 so far in order to preserve address verification attempts.
331 Argument: string to indicate what aborted the transaction
336 incomplete_transaction_log(uschar *what)
338 if (!sender_address /* No transaction in progress */
339 || !LOGGING(smtp_incomplete_transaction))
342 /* Build list of recipients for logging */
344 if (recipients_count > 0)
346 raw_recipients = store_get(recipients_count * sizeof(uschar *), GET_UNTAINTED);
347 for (int i = 0; i < recipients_count; i++)
348 raw_recipients[i] = recipients_list[i].address;
349 raw_recipients_count = recipients_count;
352 log_write(L_smtp_incomplete_transaction, LOG_MAIN|LOG_SENDER|LOG_RECIPIENTS,
353 "%s incomplete transaction (%s)", host_and_ident(TRUE), what);
360 smtp_command_timeout_exit(void)
362 log_write(L_lost_incoming_connection,
363 LOG_MAIN, "SMTP command timeout on%s connection from %s",
364 tls_in.active.sock >= 0 ? " TLS" : "", host_and_ident(FALSE));
365 if (smtp_batched_input)
366 moan_smtp_batch(NULL, "421 SMTP command timeout"); /* Does not return */
367 smtp_notquit_exit(US"command-timeout", US"421",
368 US"%s: SMTP command timeout - closing connection",
369 smtp_active_hostname);
370 exim_exit(EXIT_FAILURE);
374 smtp_command_sigterm_exit(void)
376 log_write(0, LOG_MAIN, "%s closed after SIGTERM", smtp_get_connection_info());
377 if (smtp_batched_input)
378 moan_smtp_batch(NULL, "421 SIGTERM received"); /* Does not return */
379 smtp_notquit_exit(US"signal-exit", US"421",
380 US"%s: Service not available - closing connection", smtp_active_hostname);
381 exim_exit(EXIT_FAILURE);
385 smtp_data_timeout_exit(void)
387 log_write(L_lost_incoming_connection,
388 LOG_MAIN, "SMTP data timeout (message abandoned) on connection from %s F=<%s>",
389 sender_fullhost ? sender_fullhost : US"local process", sender_address);
390 receive_bomb_out(US"data-timeout", US"SMTP incoming data timeout");
391 /* Does not return */
395 smtp_data_sigint_exit(void)
397 log_write(0, LOG_MAIN, "%s closed after %s",
398 smtp_get_connection_info(), had_data_sigint == SIGTERM ? "SIGTERM":"SIGINT");
399 receive_bomb_out(US"signal-exit",
400 US"Service not available - SIGTERM or SIGINT received");
401 /* Does not return */
405 /******************************************************************************/
406 /* SMTP input buffer handling. Most of these are similar to stdio routines. */
411 /* Set up the buffer for inputting using direct read() calls, and arrange to
412 call the local functions instead of the standard C ones. Place a NUL at the
413 end of the buffer to safety-stop C-string reads from it. */
415 if (!(smtp_inbuffer = US malloc(IN_BUFFER_SIZE)))
416 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "malloc() failed for SMTP input buffer");
417 smtp_inbuffer[IN_BUFFER_SIZE-1] = '\0';
419 smtp_inptr = smtp_inend = smtp_inbuffer;
420 smtp_had_eof = smtp_had_error = 0;
425 /* Refill the buffer, and notify DKIM verification code.
426 Return false for error or EOF.
430 smtp_refill(unsigned lim)
434 if (!smtp_out) return FALSE;
436 if (smtp_receive_timeout > 0) ALARM(smtp_receive_timeout);
438 /* Limit amount read, so non-message data is not fed to DKIM.
439 Take care to not touch the safety NUL at the end of the buffer. */
441 rc = read(fileno(smtp_in), smtp_inbuffer, MIN(IN_BUFFER_SIZE-1, lim));
443 if (smtp_receive_timeout > 0) ALARM_CLR(0);
446 /* Must put the error text in fixed store, because this might be during
447 header reading, where it releases unused store above the header. */
450 if (had_command_timeout) /* set by signal handler */
451 smtp_command_timeout_exit(); /* does not return */
452 if (had_command_sigterm)
453 smtp_command_sigterm_exit();
454 if (had_data_timeout)
455 smtp_data_timeout_exit();
457 smtp_data_sigint_exit();
459 smtp_had_error = save_errno;
460 smtp_read_error = string_copy_perm(
461 string_sprintf(" (error: %s)", strerror(save_errno)), FALSE);
468 dkim_exim_verify_feed(smtp_inbuffer, rc);
470 smtp_inend = smtp_inbuffer + rc;
471 smtp_inptr = smtp_inbuffer;
476 /* Check if there is buffered data */
481 return smtp_inptr < smtp_inend;
484 /* SMTP version of getc()
486 This gets the next byte from the SMTP input buffer. If the buffer is empty,
487 it flushes the output, and refills the buffer, with a timeout. The signal
488 handler is set appropriately by the calling function. This function is not used
489 after a connection has negotiated itself into an TLS/SSL state.
491 Arguments: lim Maximum amount to read/buffer
492 Returns: the next character or EOF
496 smtp_getc(unsigned lim)
498 if (!smtp_hasc() && !smtp_refill(lim)) return EOF;
499 return *smtp_inptr++;
502 /* Get many bytes, refilling buffer if needed */
505 smtp_getbuf(unsigned * len)
510 if (!smtp_hasc() && !smtp_refill(*len))
511 { *len = 0; return NULL; }
513 if ((size = smtp_inend - smtp_inptr) > *len) size = *len;
520 /* Copy buffered data to the dkim feed.
521 Called, unless TLS, just before starting to read message headers. */
524 smtp_get_cache(unsigned lim)
527 int n = smtp_inend - smtp_inptr;
531 dkim_exim_verify_feed(smtp_inptr, n);
536 /* SMTP version of ungetc()
537 Puts a character back in the input buffer. Only ever called once.
542 Returns: the character
548 if (smtp_inptr <= smtp_inbuffer) /* NB: NOT smtp_hasc() ! */
549 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "buffer underflow in smtp_ungetc");
556 /* SMTP version of feof()
557 Tests for a previous EOF
560 Returns: non-zero if the eof flag is set
570 /* SMTP version of ferror()
571 Tests for a previous read error, and returns with errno
572 restored to what it was when the error was detected.
575 Returns: non-zero if the error flag is set
581 errno = smtp_had_error;
582 return smtp_had_error;
586 /* Check if a getc will block or not */
589 smtp_could_getc(void)
593 struct timeval tzero = {.tv_sec = 0, .tv_usec = 0};
595 if (smtp_inptr < smtp_inend)
598 fd = fileno(smtp_in);
601 rc = select(fd + 1, (SELECT_ARG2_TYPE *)&fds, NULL, NULL, &tzero);
603 if (rc <= 0) return FALSE; /* Not ready to read */
604 rc = smtp_getc(GETC_BUFFER_UNLIMITED);
605 if (rc < 0) return FALSE; /* End of file or error */
612 /******************************************************************************/
613 /*************************************************
614 * Recheck synchronization *
615 *************************************************/
617 /* Synchronization checks can never be perfect because a packet may be on its
618 way but not arrived when the check is done. Normally, the checks happen when
619 commands are read: Exim ensures that there is no more input in the input buffer.
620 In normal cases, the response to the command will be fast, and there is no
623 However, for some commands an ACL is run, and that can include delays. In those
624 cases, it is useful to do another check on the input just before sending the
625 response. This also applies at the start of a connection. This function does
626 that check by means of the select() function, as long as the facility is not
627 disabled or inappropriate. A failure of select() is ignored.
629 When there is unwanted input, we read it so that it appears in the log of the
633 Returns: TRUE if all is well; FALSE if there is input pending
637 wouldblock_reading(void)
640 if (tls_in.active.sock >= 0)
641 return !tls_could_getc();
644 return !smtp_could_getc();
650 if (!smtp_enforce_sync || !sender_host_address || f.sender_host_notsocket)
653 return wouldblock_reading();
657 /******************************************************************************/
658 /* Variants of the smtp_* input handling functions for use in CHUNKING mode */
660 /* Forward declarations */
661 static inline void bdat_push_receive_functions(void);
662 static inline void bdat_pop_receive_functions(void);
665 /* Get a byte from the smtp input, in CHUNKING mode. Handle ack of the
666 previous BDAT chunk and getting new ones when we run out. Uses the
667 underlying smtp_getc or tls_getc both for that and for getting the
668 (buffered) data byte. EOD signals (an expected) no further data.
669 ERR signals a protocol error, and EOF a closed input stream.
671 Called from read_bdat_smtp() in receive.c for the message body, but also
672 by the headers read loop in receive_msg(); manipulates chunking_state
673 to handle the BDAT command/response.
674 Placed here due to the correlation with the above smtp_getc(), which it wraps,
675 and also by the need to do smtp command/response handling.
677 Arguments: lim (ignored)
678 Returns: the next character or ERR, EOD or EOF
682 bdat_getc(unsigned lim)
684 uschar * user_msg = NULL;
693 if (chunking_data_left > 0)
694 return lwr_receive_getc(chunking_data_left--);
696 bdat_pop_receive_functions();
698 dkim_save = dkim_collect_input;
699 dkim_collect_input = 0;
702 /* Unless PIPELINING was offered, there should be no next command
703 until after we ack that chunk */
705 if (!f.smtp_in_pipelining_advertised && !check_sync())
707 unsigned n = smtp_inend - smtp_inptr;
710 incomplete_transaction_log(US"sync failure");
711 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP protocol synchronization error "
712 "(next input sent too soon: pipelining was not advertised): "
713 "rejected \"%s\" %s next input=\"%s\"%s",
714 smtp_cmd_buffer, host_and_ident(TRUE),
715 string_printing(string_copyn(smtp_inptr, n)),
716 smtp_inend - smtp_inptr > n ? "..." : "");
717 (void) synprot_error(L_smtp_protocol_error, 554, NULL,
718 US"SMTP synchronization error");
719 goto repeat_until_rset;
722 /* If not the last, ack the received chunk. The last response is delayed
723 until after the data ACL decides on it */
725 if (chunking_state == CHUNKING_LAST)
728 dkim_collect_input = dkim_save;
729 dkim_exim_verify_feed(NULL, 0); /* notify EOD */
730 dkim_collect_input = 0;
735 smtp_printf("250 %u byte chunk received\r\n", FALSE, chunking_datasize);
736 chunking_state = CHUNKING_OFFERED;
737 DEBUG(D_receive) debug_printf("chunking state %d\n", (int)chunking_state);
739 /* Expect another BDAT cmd from input. RFC 3030 says nothing about
740 QUIT, RSET or NOOP but handling them seems obvious */
743 switch(smtp_read_command(TRUE, 1))
746 (void) synprot_error(L_smtp_protocol_error, 503, NULL,
747 US"only BDAT permissible after non-LAST BDAT");
750 switch(smtp_read_command(TRUE, 1))
752 case QUIT_CMD: smtp_quit_handler(&user_msg, &log_msg); /*FALLTHROUGH */
753 case EOF_CMD: return EOF;
754 case RSET_CMD: smtp_rset_handler(); return ERR;
755 default: if (synprot_error(L_smtp_protocol_error, 503, NULL,
756 US"only RSET accepted now") > 0)
758 goto repeat_until_rset;
762 smtp_quit_handler(&user_msg, &log_msg);
773 smtp_printf("250 OK\r\n", FALSE);
780 if (sscanf(CS smtp_cmd_data, "%u %n", &chunking_datasize, &n) < 1)
782 (void) synprot_error(L_smtp_protocol_error, 501, NULL,
783 US"missing size for BDAT command");
786 chunking_state = strcmpic(smtp_cmd_data+n, US"LAST") == 0
787 ? CHUNKING_LAST : CHUNKING_ACTIVE;
788 chunking_data_left = chunking_datasize;
789 DEBUG(D_receive) debug_printf("chunking state %d, %d bytes\n",
790 (int)chunking_state, chunking_data_left);
792 if (chunking_datasize == 0)
793 if (chunking_state == CHUNKING_LAST)
797 (void) synprot_error(L_smtp_protocol_error, 504, NULL,
798 US"zero size for BDAT command");
799 goto repeat_until_rset;
802 bdat_push_receive_functions();
804 dkim_collect_input = dkim_save;
806 break; /* to top of main loop */
815 if (chunking_data_left > 0)
816 return lwr_receive_hasc();
821 bdat_getbuf(unsigned * len)
825 if (chunking_data_left <= 0)
826 { *len = 0; return NULL; }
828 if (*len > chunking_data_left) *len = chunking_data_left;
829 buf = lwr_receive_getbuf(len); /* Either smtp_getbuf or tls_getbuf */
830 chunking_data_left -= *len;
835 bdat_flush_data(void)
837 while (chunking_data_left)
839 unsigned n = chunking_data_left;
840 if (!bdat_getbuf(&n)) break;
843 bdat_pop_receive_functions();
844 chunking_state = CHUNKING_OFFERED;
845 DEBUG(D_receive) debug_printf("chunking state %d\n", (int)chunking_state);
850 bdat_push_receive_functions(void)
852 /* push the current receive_* function on the "stack", and
853 replace them by bdat_getc(), which in turn will use the lwr_receive_*
854 functions to do the dirty work. */
855 if (!lwr_receive_getc)
857 lwr_receive_getc = receive_getc;
858 lwr_receive_getbuf = receive_getbuf;
859 lwr_receive_hasc = receive_hasc;
860 lwr_receive_ungetc = receive_ungetc;
864 DEBUG(D_receive) debug_printf("chunking double-push receive functions\n");
867 receive_getc = bdat_getc;
868 receive_getbuf = bdat_getbuf;
869 receive_hasc = bdat_hasc;
870 receive_ungetc = bdat_ungetc;
874 bdat_pop_receive_functions(void)
876 if (!lwr_receive_getc)
878 DEBUG(D_receive) debug_printf("chunking double-pop receive functions\n");
881 receive_getc = lwr_receive_getc;
882 receive_getbuf = lwr_receive_getbuf;
883 receive_hasc = lwr_receive_hasc;
884 receive_ungetc = lwr_receive_ungetc;
886 lwr_receive_getc = NULL;
887 lwr_receive_getbuf = NULL;
888 lwr_receive_hasc = NULL;
889 lwr_receive_ungetc = NULL;
895 chunking_data_left++;
896 bdat_push_receive_functions(); /* we're not done yet, calling push is safe, because it checks the state before pushing anything */
897 return lwr_receive_ungetc(ch);
902 /******************************************************************************/
904 /*************************************************
905 * Write formatted string to SMTP channel *
906 *************************************************/
908 /* This is a separate function so that we don't have to repeat everything for
909 TLS support or debugging. It is global so that the daemon and the
910 authentication functions can use it. It does not return any error indication,
911 because major problems such as dropped connections won't show up till an output
912 flush for non-TLS connections. The smtp_fflush() function is available for
913 checking that: for convenience, TLS output errors are remembered here so that
914 they are also picked up later by smtp_fflush().
916 This function is exposed to the local_scan API; do not change the signature.
920 more further data expected
921 ... optional arguments
927 smtp_printf(const char *format, BOOL more, ...)
932 smtp_vprintf(format, more, ap);
936 /* This is split off so that verify.c:respond_printf() can, in effect, call
937 smtp_printf(), bearing in mind that in C a vararg function can't directly
938 call another vararg function, only a function which accepts a va_list.
940 This function is exposed to the local_scan API; do not change the signature.
942 /*XXX consider passing caller-info in, for string_vformat-onward */
945 smtp_vprintf(const char *format, BOOL more, va_list ap)
947 gstring gs = { .size = big_buffer_size, .ptr = 0, .s = big_buffer };
950 /* Use taint-unchecked routines for writing into big_buffer, trusting
951 that we'll never expand it. */
953 yield = !! string_vformat(&gs, SVFMT_TAINT_NOCHK, format, ap);
954 string_from_gstring(&gs);
956 DEBUG(D_receive) for (const uschar * t, * s = gs.s;
957 s && (t = Ustrchr(s, '\r'));
958 s = t + 2) /* \r\n */
959 debug_printf("%s %.*s\n",
960 s == gs.s ? "SMTP>>" : " ",
965 log_write(0, LOG_MAIN|LOG_PANIC, "string too large in smtp_printf()");
966 smtp_closedown(US"Unexpected error");
967 exim_exit(EXIT_FAILURE);
970 /* If this is the first output for a (non-batch) RCPT command, see if all RCPTs
971 have had the same. Note: this code is also present in smtp_respond(). It would
972 be tidier to have it only in one place, but when it was added, it was easier to
973 do it that way, so as not to have to mess with the code for the RCPT command,
974 which sometimes uses smtp_printf() and sometimes smtp_respond(). */
976 if (fl.rcpt_in_progress)
978 if (!rcpt_smtp_response)
979 rcpt_smtp_response = string_copy(big_buffer);
980 else if (fl.rcpt_smtp_response_same &&
981 Ustrcmp(rcpt_smtp_response, big_buffer) != 0)
982 fl.rcpt_smtp_response_same = FALSE;
983 fl.rcpt_in_progress = FALSE;
986 /* Now write the string */
990 tls_in.active.sock >= 0 ? (tls_write(NULL, gs.s, gs.ptr, more) < 0) :
992 (fwrite(gs.s, gs.ptr, 1, smtp_out) == 0)
994 smtp_write_error = -1;
999 /*************************************************
1000 * Flush SMTP out and check for error *
1001 *************************************************/
1003 /* This function isn't currently used within Exim (it detects errors when it
1004 tries to read the next SMTP input), but is available for use in local_scan().
1005 It flushes the output and checks for errors.
1008 Returns: 0 for no error; -1 after an error
1014 if (tls_in.active.sock < 0 && fflush(smtp_out) != 0) smtp_write_error = -1;
1018 tls_in.active.sock >= 0 ? (tls_write(NULL, NULL, 0, FALSE) < 0) :
1020 (fflush(smtp_out) != 0)
1022 smtp_write_error = -1;
1024 return smtp_write_error;
1029 /* If there's input waiting (and we're doing pipelineing) then we can pipeline
1030 a reponse with the one following. */
1033 pipeline_response(void)
1035 if ( !smtp_enforce_sync || !sender_host_address
1036 || f.sender_host_notsocket || !f.smtp_in_pipelining_advertised)
1039 if (wouldblock_reading()) return FALSE;
1040 f.smtp_in_pipelining_used = TRUE;
1045 #ifndef DISABLE_PIPE_CONNECT
1047 pipeline_connect_sends(void)
1049 if (!sender_host_address || f.sender_host_notsocket || !fl.pipe_connect_acceptable)
1052 if (wouldblock_reading()) return FALSE;
1053 f.smtp_in_early_pipe_used = TRUE;
1058 /*************************************************
1059 * SMTP command read timeout *
1060 *************************************************/
1062 /* Signal handler for timing out incoming SMTP commands. This attempts to
1065 Argument: signal number (SIGALRM)
1070 command_timeout_handler(int sig)
1072 had_command_timeout = sig;
1077 /*************************************************
1078 * SIGTERM received *
1079 *************************************************/
1081 /* Signal handler for handling SIGTERM. Again, try to finish tidily.
1083 Argument: signal number (SIGTERM)
1088 command_sigterm_handler(int sig)
1090 had_command_sigterm = sig;
1096 #ifdef SUPPORT_PROXY
1097 /*************************************************
1098 * Check if host is required proxy host *
1099 *************************************************/
1100 /* The function determines if inbound host will be a regular smtp host
1101 or if it is configured that it must use Proxy Protocol. A local
1109 check_proxy_protocol_host()
1113 if ( sender_host_address
1114 && (rc = verify_check_this_host(CUSS &hosts_proxy, NULL, NULL,
1115 sender_host_address, NULL)) == OK)
1118 debug_printf("Detected proxy protocol configured host\n");
1119 proxy_session = TRUE;
1121 return proxy_session;
1125 /*************************************************
1126 * Read data until newline or end of buffer *
1127 *************************************************/
1128 /* While SMTP is server-speaks-first, TLS is client-speaks-first, so we can't
1129 read an entire buffer and assume there will be nothing past a proxy protocol
1130 header. Our approach normally is to use stdio, but again that relies upon
1131 "STARTTLS\r\n" and a server response before the client starts TLS handshake, or
1132 reading _nothing_ before client TLS handshake. So we don't want to use the
1133 usual buffering reads which may read enough to block TLS starting.
1135 So unfortunately we're down to "read one byte at a time, with a syscall each,
1136 and expect a little overhead", for all proxy-opened connections which are v1,
1137 just to handle the TLS-on-connect case. Since SSL functions wrap the
1138 underlying fd, we can't assume that we can feed them any already-read content.
1140 We need to know where to read to, the max capacity, and we'll read until we
1141 get a CR and one more character. Let the caller scream if it's CR+!LF.
1143 Return the amount read.
1147 swallow_until_crlf(int fd, uschar *base, int already, int capacity)
1149 uschar *to = base + already;
1155 /* For "PROXY UNKNOWN\r\n" we, at time of writing, expect to have read
1156 up through the \r; for the _normal_ case, we haven't yet seen the \r. */
1158 cr = memchr(base, '\r', already);
1161 if ((cr - base) < already - 1)
1163 /* \r and presumed \n already within what we have; probably not
1164 actually proxy protocol, but abort cleanly. */
1167 /* \r is last character read, just need one more. */
1171 while (capacity > 0)
1173 do { ret = read(fd, to, 1); } while (ret == -1 && errno == EINTR && !had_command_timeout);
1185 /* reached end without having room for a final newline, abort */
1190 /*************************************************
1191 * Setup host for proxy protocol *
1192 *************************************************/
1193 /* The function configures the connection based on a header from the
1194 inbound host to use Proxy Protocol. The specification is very exact
1195 so exit with an error if do not find the exact required pieces. This
1196 includes an incorrect number of spaces separating args.
1199 Returns: Boolean success
1203 setup_proxy_protocol_host()
1215 struct { /* TCP/UDP over IPv4, len = 12 */
1221 struct { /* TCP/UDP over IPv6, len = 36 */
1222 uint8_t src_addr[16];
1223 uint8_t dst_addr[16];
1227 struct { /* AF_UNIX sockets, len = 216 */
1228 uschar src_addr[108];
1229 uschar dst_addr[108];
1235 /* Temp variables used in PPv2 address:port parsing */
1237 char tmpip[INET_ADDRSTRLEN];
1238 struct sockaddr_in tmpaddr;
1239 char tmpip6[INET6_ADDRSTRLEN];
1240 struct sockaddr_in6 tmpaddr6;
1242 /* We can't read "all data until end" because while SMTP is
1243 server-speaks-first, the TLS handshake is client-speaks-first, so for
1244 TLS-on-connect ports the proxy protocol header will usually be immediately
1245 followed by a TLS handshake, and with N TLS libraries, we can't reliably
1246 reinject data for reading by those. So instead we first read "enough to be
1247 safely read within the header, and figure out how much more to read".
1248 For v1 we will later read to the end-of-line, for v2 we will read based upon
1251 The v2 sig is 12 octets, and another 4 gets us the length, so we know how much
1252 data is needed total. For v1, where the line looks like:
1253 PROXY TCPn L3src L3dest SrcPort DestPort \r\n
1255 However, for v1 there's also `PROXY UNKNOWN\r\n` which is only 15 octets.
1256 We seem to support that. So, if we read 14 octets then we can tell if we're
1257 v2 or v1. If we're v1, we can continue reading as normal.
1259 If we're v2, we can't slurp up the entire header. We need the length in the
1260 15th & 16th octets, then to read everything after that.
1262 So to safely handle v1 and v2, with client-sent-first supported correctly,
1263 we have to do a minimum of 3 read calls, not 1. Eww.
1266 #define PROXY_INITIAL_READ 14
1267 #define PROXY_V2_HEADER_SIZE 16
1268 #if PROXY_INITIAL_READ > PROXY_V2_HEADER_SIZE
1269 # error Code bug in sizes of data to read for proxy usage
1274 int fd = fileno(smtp_in);
1275 const char v2sig[12] = "\x0D\x0A\x0D\x0A\x00\x0D\x0A\x51\x55\x49\x54\x0A";
1276 uschar * iptype; /* To display debug info */
1277 socklen_t vslen = sizeof(struct timeval);
1280 os_non_restarting_signal(SIGALRM, command_timeout_handler);
1281 ALARM(proxy_protocol_timeout);
1285 /* The inbound host was declared to be a Proxy Protocol host, so
1286 don't do a PEEK into the data, actually slurp up enough to be
1287 "safe". Can't take it all because TLS-on-connect clients follow
1288 immediately with TLS handshake. */
1289 ret = read(fd, &hdr, PROXY_INITIAL_READ);
1291 while (ret == -1 && errno == EINTR && !had_command_timeout);
1296 /* For v2, handle reading the length, and then the rest. */
1297 if ((ret == PROXY_INITIAL_READ) && (memcmp(&hdr.v2, v2sig, sizeof(v2sig)) == 0))
1302 /* First get the length fields. */
1305 retmore = read(fd, (uschar*)&hdr + ret, PROXY_V2_HEADER_SIZE - PROXY_INITIAL_READ);
1306 } while (retmore == -1 && errno == EINTR && !had_command_timeout);
1311 ver = (hdr.v2.ver_cmd & 0xf0) >> 4;
1313 /* May 2014: haproxy combined the version and command into one byte to
1314 allow two full bytes for the length field in order to proxy SSL
1315 connections. SSL Proxy is not supported in this version of Exim, but
1316 must still separate values here. */
1320 DEBUG(D_receive) debug_printf("Invalid Proxy Protocol version: %d\n", ver);
1324 /* The v2 header will always be 16 bytes per the spec. */
1325 size = 16 + ntohs(hdr.v2.len);
1326 DEBUG(D_receive) debug_printf("Detected PROXYv2 header, size %d (limit %d)\n",
1327 size, (int)sizeof(hdr));
1329 /* We should now have 16 octets (PROXY_V2_HEADER_SIZE), and we know the total
1330 amount that we need. Double-check that the size is not unreasonable, then
1332 if (size > sizeof(hdr))
1334 DEBUG(D_receive) debug_printf("PROXYv2 header size unreasonably large; security attack?\n");
1342 retmore = read(fd, (uschar*)&hdr + ret, size-ret);
1343 } while (retmore == -1 && errno == EINTR && !had_command_timeout);
1347 DEBUG(D_receive) debug_printf("PROXYv2: have %d/%d required octets\n", ret, size);
1348 } while (ret < size);
1350 } /* end scope for getting rest of data for v2 */
1352 /* At this point: if PROXYv2, we've read the exact size required for all data;
1353 if PROXYv1 then we've read "less than required for any valid line" and should
1356 if (ret >= 16 && memcmp(&hdr.v2, v2sig, 12) == 0)
1358 uint8_t cmd = (hdr.v2.ver_cmd & 0x0f);
1362 case 0x01: /* PROXY command */
1365 case 0x11: /* TCPv4 address type */
1367 tmpaddr.sin_addr.s_addr = hdr.v2.addr.ip4.src_addr;
1368 inet_ntop(AF_INET, &tmpaddr.sin_addr, CS &tmpip, sizeof(tmpip));
1369 if (!string_is_ip_address(US tmpip, NULL))
1371 DEBUG(D_receive) debug_printf("Invalid %s source IP\n", iptype);
1374 proxy_local_address = sender_host_address;
1375 sender_host_address = string_copy(US tmpip);
1376 tmpport = ntohs(hdr.v2.addr.ip4.src_port);
1377 proxy_local_port = sender_host_port;
1378 sender_host_port = tmpport;
1379 /* Save dest ip/port */
1380 tmpaddr.sin_addr.s_addr = hdr.v2.addr.ip4.dst_addr;
1381 inet_ntop(AF_INET, &tmpaddr.sin_addr, CS &tmpip, sizeof(tmpip));
1382 if (!string_is_ip_address(US tmpip, NULL))
1384 DEBUG(D_receive) debug_printf("Invalid %s dest port\n", iptype);
1387 proxy_external_address = string_copy(US tmpip);
1388 tmpport = ntohs(hdr.v2.addr.ip4.dst_port);
1389 proxy_external_port = tmpport;
1391 case 0x21: /* TCPv6 address type */
1393 memmove(tmpaddr6.sin6_addr.s6_addr, hdr.v2.addr.ip6.src_addr, 16);
1394 inet_ntop(AF_INET6, &tmpaddr6.sin6_addr, CS &tmpip6, sizeof(tmpip6));
1395 if (!string_is_ip_address(US tmpip6, NULL))
1397 DEBUG(D_receive) debug_printf("Invalid %s source IP\n", iptype);
1400 proxy_local_address = sender_host_address;
1401 sender_host_address = string_copy(US tmpip6);
1402 tmpport = ntohs(hdr.v2.addr.ip6.src_port);
1403 proxy_local_port = sender_host_port;
1404 sender_host_port = tmpport;
1405 /* Save dest ip/port */
1406 memmove(tmpaddr6.sin6_addr.s6_addr, hdr.v2.addr.ip6.dst_addr, 16);
1407 inet_ntop(AF_INET6, &tmpaddr6.sin6_addr, CS &tmpip6, sizeof(tmpip6));
1408 if (!string_is_ip_address(US tmpip6, NULL))
1410 DEBUG(D_receive) debug_printf("Invalid %s dest port\n", iptype);
1413 proxy_external_address = string_copy(US tmpip6);
1414 tmpport = ntohs(hdr.v2.addr.ip6.dst_port);
1415 proxy_external_port = tmpport;
1419 debug_printf("Unsupported PROXYv2 connection type: 0x%02x\n",
1423 /* Unsupported protocol, keep local connection address */
1425 case 0x00: /* LOCAL command */
1426 /* Keep local connection address for LOCAL */
1431 debug_printf("Unsupported PROXYv2 command: 0x%x\n", cmd);
1435 else if (ret >= 8 && memcmp(hdr.v1.line, "PROXY", 5) == 0)
1439 uschar *sp; /* Utility variables follow */
1444 /* get the rest of the line */
1445 r2 = swallow_until_crlf(fd, (uschar*)&hdr, ret, sizeof(hdr)-ret);
1450 p = string_copy(hdr.v1.line);
1451 end = memchr(p, '\r', ret - 1);
1453 if (!end || (end == (uschar*)&hdr + ret) || end[1] != '\n')
1455 DEBUG(D_receive) debug_printf("Partial or invalid PROXY header\n");
1458 *end = '\0'; /* Terminate the string */
1459 size = end + 2 - p; /* Skip header + CRLF */
1460 DEBUG(D_receive) debug_printf("Detected PROXYv1 header\n");
1461 DEBUG(D_receive) debug_printf("Bytes read not within PROXY header: %d\n", ret - size);
1462 /* Step through the string looking for the required fields. Ensure
1463 strict adherence to required formatting, exit for any error. */
1465 if (!isspace(*(p++)))
1467 DEBUG(D_receive) debug_printf("Missing space after PROXY command\n");
1470 if (!Ustrncmp(p, CCS"TCP4", 4))
1472 else if (!Ustrncmp(p,CCS"TCP6", 4))
1474 else if (!Ustrncmp(p,CCS"UNKNOWN", 7))
1476 iptype = US"Unknown";
1481 DEBUG(D_receive) debug_printf("Invalid TCP type\n");
1485 p += Ustrlen(iptype);
1486 if (!isspace(*(p++)))
1488 DEBUG(D_receive) debug_printf("Missing space after TCP4/6 command\n");
1491 /* Find the end of the arg */
1492 if ((sp = Ustrchr(p, ' ')) == NULL)
1495 debug_printf("Did not find proxied src %s\n", iptype);
1499 if(!string_is_ip_address(p, NULL))
1502 debug_printf("Proxied src arg is not an %s address\n", iptype);
1505 proxy_local_address = sender_host_address;
1506 sender_host_address = p;
1508 if ((sp = Ustrchr(p, ' ')) == NULL)
1511 debug_printf("Did not find proxy dest %s\n", iptype);
1515 if(!string_is_ip_address(p, NULL))
1518 debug_printf("Proxy dest arg is not an %s address\n", iptype);
1521 proxy_external_address = p;
1523 if ((sp = Ustrchr(p, ' ')) == NULL)
1525 DEBUG(D_receive) debug_printf("Did not find proxied src port\n");
1529 tmp_port = strtol(CCS p, &endc, 10);
1530 if (*endc || tmp_port == 0)
1533 debug_printf("Proxied src port '%s' not an integer\n", p);
1536 proxy_local_port = sender_host_port;
1537 sender_host_port = tmp_port;
1539 if ((sp = Ustrchr(p, '\0')) == NULL)
1541 DEBUG(D_receive) debug_printf("Did not find proxy dest port\n");
1544 tmp_port = strtol(CCS p, &endc, 10);
1545 if (*endc || tmp_port == 0)
1548 debug_printf("Proxy dest port '%s' not an integer\n", p);
1551 proxy_external_port = tmp_port;
1552 /* Already checked for /r /n above. Good V1 header received. */
1556 /* Wrong protocol */
1557 DEBUG(D_receive) debug_printf("Invalid proxy protocol version negotiation\n");
1558 (void) swallow_until_crlf(fd, (uschar*)&hdr, ret, sizeof(hdr)-ret);
1564 debug_printf("Valid %s sender from Proxy Protocol header\n", iptype);
1565 yield = proxy_session;
1567 /* Don't flush any potential buffer contents. Any input on proxyfail
1568 should cause a synchronization failure */
1571 DEBUG(D_receive) if (had_command_timeout)
1572 debug_printf("Timeout while reading proxy header\n");
1577 sender_host_name = NULL;
1578 (void) host_name_lookup();
1579 host_build_sender_fullhost();
1583 f.proxy_session_failed = TRUE;
1585 debug_printf("Failure to extract proxied host, only QUIT allowed\n");
1593 /*************************************************
1594 * Read one command line *
1595 *************************************************/
1597 /* Strictly, SMTP commands coming over the net are supposed to end with CRLF.
1598 There are sites that don't do this, and in any case internal SMTP probably
1599 should check only for LF. Consequently, we check here for LF only. The line
1600 ends up with [CR]LF removed from its end. If we get an overlong line, treat as
1601 an unknown command. The command is read into the global smtp_cmd_buffer so that
1602 it is available via $smtp_command.
1604 The character reading routine sets up a timeout for each block actually read
1605 from the input (which may contain more than one command). We set up a special
1606 signal handler that closes down the session on a timeout. Control does not
1607 return when it runs.
1610 check_sync if TRUE, check synchronization rules if global option is TRUE
1611 buffer_lim maximum to buffer in lower layer
1613 Returns: a code identifying the command (enumerated above)
1617 smtp_read_command(BOOL check_sync, unsigned buffer_lim)
1621 BOOL hadnull = FALSE;
1623 had_command_timeout = 0;
1624 os_non_restarting_signal(SIGALRM, command_timeout_handler);
1626 while ((c = (receive_getc)(buffer_lim)) != '\n' && c != EOF)
1628 if (ptr >= SMTP_CMD_BUFFER_SIZE)
1630 os_non_restarting_signal(SIGALRM, sigalrm_handler);
1638 smtp_cmd_buffer[ptr++] = c;
1641 receive_linecount++; /* For BSMTP errors */
1642 os_non_restarting_signal(SIGALRM, sigalrm_handler);
1644 /* If hit end of file, return pseudo EOF command. Whether we have a
1645 part-line already read doesn't matter, since this is an error state. */
1647 if (c == EOF) return EOF_CMD;
1649 /* Remove any CR and white space at the end of the line, and terminate the
1652 while (ptr > 0 && isspace(smtp_cmd_buffer[ptr-1])) ptr--;
1653 smtp_cmd_buffer[ptr] = 0;
1655 DEBUG(D_receive) debug_printf("SMTP<< %s\n", smtp_cmd_buffer);
1657 /* NULLs are not allowed in SMTP commands */
1659 if (hadnull) return BADCHAR_CMD;
1661 /* Scan command list and return identity, having set the data pointer
1662 to the start of the actual data characters. Check for SMTP synchronization
1665 for (smtp_cmd_list * p = cmd_list; p < cmd_list_end; p++)
1667 #ifdef SUPPORT_PROXY
1668 /* Only allow QUIT command if Proxy Protocol parsing failed */
1669 if (proxy_session && f.proxy_session_failed && p->cmd != QUIT_CMD)
1673 && strncmpic(smtp_cmd_buffer, US p->name, p->len) == 0
1674 && ( smtp_cmd_buffer[p->len-1] == ':' /* "mail from:" or "rcpt to:" */
1675 || smtp_cmd_buffer[p->len] == 0
1676 || smtp_cmd_buffer[p->len] == ' '
1679 if ( smtp_inptr < smtp_inend /* Outstanding input */
1680 && p->cmd < sync_cmd_limit /* Command should sync */
1681 && check_sync /* Local flag set */
1682 && smtp_enforce_sync /* Global flag set */
1683 && sender_host_address != NULL /* Not local input */
1684 && !f.sender_host_notsocket /* Really is a socket */
1688 /* The variables $smtp_command and $smtp_command_argument point into the
1689 unmodified input buffer. A copy of the latter is taken for actual
1690 processing, so that it can be chopped up into separate parts if necessary,
1691 for example, when processing a MAIL command options such as SIZE that can
1692 follow the sender address. */
1694 smtp_cmd_argument = smtp_cmd_buffer + p->len;
1695 while (isspace(*smtp_cmd_argument)) smtp_cmd_argument++;
1696 Ustrcpy(smtp_data_buffer, smtp_cmd_argument);
1697 smtp_cmd_data = smtp_data_buffer;
1699 /* Count non-mail commands from those hosts that are controlled in this
1700 way. The default is all hosts. We don't waste effort checking the list
1701 until we get a non-mail command, but then cache the result to save checking
1702 again. If there's a DEFER while checking the host, assume it's in the list.
1704 Note that one instance of RSET, EHLO/HELO, and STARTTLS is allowed at the
1705 start of each incoming message by fiddling with the value in the table. */
1707 if (!p->is_mail_cmd)
1709 if (count_nonmail == TRUE_UNSET) count_nonmail =
1710 verify_check_host(&smtp_accept_max_nonmail_hosts) != FAIL;
1711 if (count_nonmail && ++nonmail_command_count > smtp_accept_max_nonmail)
1712 return TOO_MANY_NONMAIL_CMD;
1715 /* If there is data for a command that does not expect it, generate the
1718 return (p->has_arg || *smtp_cmd_data == 0)? p->cmd : BADARG_CMD;
1722 #ifdef SUPPORT_PROXY
1723 /* Only allow QUIT command if Proxy Protocol parsing failed */
1724 if (proxy_session && f.proxy_session_failed)
1725 return PROXY_FAIL_IGNORE_CMD;
1728 /* Enforce synchronization for unknown commands */
1730 if ( smtp_inptr < smtp_inend /* Outstanding input */
1731 && check_sync /* Local flag set */
1732 && smtp_enforce_sync /* Global flag set */
1733 && sender_host_address /* Not local input */
1734 && !f.sender_host_notsocket /* Really is a socket */
1743 /*************************************************
1744 * Forced closedown of call *
1745 *************************************************/
1747 /* This function is called from log.c when Exim is dying because of a serious
1748 disaster, and also from some other places. If an incoming non-batched SMTP
1749 channel is open, it swallows the rest of the incoming message if in the DATA
1750 phase, sends the reply string, and gives an error to all subsequent commands
1751 except QUIT. The existence of an SMTP call is detected by the non-NULLness of
1755 message SMTP reply string to send, excluding the code
1761 smtp_closedown(uschar * message)
1763 if (!smtp_in || smtp_batched_input) return;
1764 receive_swallow_smtp();
1765 smtp_printf("421 %s\r\n", FALSE, message);
1767 for (;;) switch(smtp_read_command(FALSE, GETC_BUFFER_UNLIMITED))
1773 f.smtp_in_quit = TRUE;
1774 smtp_printf("221 %s closing connection\r\n", FALSE, smtp_active_hostname);
1779 smtp_printf("250 Reset OK\r\n", FALSE);
1783 smtp_printf("421 %s\r\n", FALSE, message);
1791 /*************************************************
1792 * Set up connection info for logging *
1793 *************************************************/
1795 /* This function is called when logging information about an SMTP connection.
1796 It sets up appropriate source information, depending on the type of connection.
1797 If sender_fullhost is NULL, we are at a very early stage of the connection;
1798 just use the IP address.
1801 Returns: a string describing the connection
1805 smtp_get_connection_info(void)
1807 const uschar * hostname = sender_fullhost
1808 ? sender_fullhost : sender_host_address;
1811 return string_sprintf("SMTP connection from %s", hostname);
1813 if (f.sender_host_unknown || f.sender_host_notsocket)
1814 return string_sprintf("SMTP connection from %s", sender_ident);
1817 return string_sprintf("SMTP connection from %s (via inetd)", hostname);
1819 if (LOGGING(incoming_interface) && interface_address)
1820 return string_sprintf("SMTP connection from %s I=[%s]:%d", hostname,
1821 interface_address, interface_port);
1823 return string_sprintf("SMTP connection from %s", hostname);
1829 /* Append TLS-related information to a log line
1832 g String under construction: allocated string to extend, or NULL
1834 Returns: Allocated string or NULL
1837 s_tlslog(gstring * g)
1839 if (LOGGING(tls_cipher) && tls_in.cipher)
1841 g = string_append(g, 2, US" X=", tls_in.cipher);
1842 #ifndef DISABLE_TLS_RESUME
1843 if (LOGGING(tls_resumption) && tls_in.resumption & RESUME_USED)
1844 g = string_catn(g, US"*", 1);
1847 if (LOGGING(tls_certificate_verified) && tls_in.cipher)
1848 g = string_append(g, 2, US" CV=", tls_in.certificate_verified? "yes":"no");
1849 if (LOGGING(tls_peerdn) && tls_in.peerdn)
1850 g = string_append(g, 3, US" DN=\"", string_printing(tls_in.peerdn), US"\"");
1851 if (LOGGING(tls_sni) && tls_in.sni)
1852 g = string_append(g, 2, US" SNI=", string_printing2(tls_in.sni, SP_TAB|SP_SPACE));
1860 s_connhad_log(gstring * g)
1862 const uschar * sep = smtp_connection_had[SMTP_HBUFF_SIZE-1] != SCH_NONE
1863 ? US" C=..." : US" C=";
1865 for (int i = smtp_ch_index; i < SMTP_HBUFF_SIZE; i++)
1866 if (smtp_connection_had[i] != SCH_NONE)
1868 g = string_append(g, 2, sep, smtp_names[smtp_connection_had[i]]);
1871 for (int i = 0; i < smtp_ch_index; i++, sep = US",")
1872 g = string_append(g, 2, sep, smtp_names[smtp_connection_had[i]]);
1877 /*************************************************
1878 * Log lack of MAIL if so configured *
1879 *************************************************/
1881 /* This function is called when an SMTP session ends. If the log selector
1882 smtp_no_mail is set, write a log line giving some details of what has happened
1883 in the SMTP session.
1890 smtp_log_no_mail(void)
1895 if (smtp_mailcmd_count > 0 || !LOGGING(smtp_no_mail))
1898 if (sender_host_authenticated)
1900 g = string_append(g, 2, US" A=", sender_host_authenticated);
1901 if (authenticated_id) g = string_append(g, 2, US":", authenticated_id);
1908 g = s_connhad_log(g);
1910 if (!(s = string_from_gstring(g))) s = US"";
1912 log_write(0, LOG_MAIN, "no MAIL in %sSMTP connection from %s D=%s%s",
1913 f.tcp_in_fastopen ? f.tcp_in_fastopen_data ? US"TFO* " : US"TFO " : US"",
1914 host_and_ident(FALSE), string_timesince(&smtp_connection_start), s);
1918 /* Return list of recent smtp commands */
1923 gstring * list = NULL;
1926 for (int i = smtp_ch_index; i < SMTP_HBUFF_SIZE; i++)
1927 if (smtp_connection_had[i] != SCH_NONE)
1928 list = string_append_listele(list, ',', smtp_names[smtp_connection_had[i]]);
1930 for (int i = 0; i < smtp_ch_index; i++)
1931 list = string_append_listele(list, ',', smtp_names[smtp_connection_had[i]]);
1933 s = string_from_gstring(list);
1934 return s ? s : US"";
1940 /*************************************************
1941 * Check HELO line and set sender_helo_name *
1942 *************************************************/
1944 /* Check the format of a HELO line. The data for HELO/EHLO is supposed to be
1945 the domain name of the sending host, or an ip literal in square brackets. The
1946 argument is placed in sender_helo_name, which is in malloc store, because it
1947 must persist over multiple incoming messages. If helo_accept_junk is set, this
1948 host is permitted to send any old junk (needed for some broken hosts).
1949 Otherwise, helo_allow_chars can be used for rogue characters in general
1950 (typically people want to let in underscores).
1953 s the data portion of the line (already past any white space)
1955 Returns: TRUE or FALSE
1959 check_helo(uschar *s)
1962 uschar *end = s + Ustrlen(s);
1963 BOOL yield = fl.helo_accept_junk;
1965 /* Discard any previous helo name */
1967 sender_helo_name = NULL;
1969 /* Skip tests if junk is permitted. */
1973 /* Allow the new standard form for IPv6 address literals, namely,
1974 [IPv6:....], and because someone is bound to use it, allow an equivalent
1975 IPv4 form. Allow plain addresses as well. */
1982 if (strncmpic(s, US"[IPv6:", 6) == 0)
1983 yield = (string_is_ip_address(s+6, NULL) == 6);
1984 else if (strncmpic(s, US"[IPv4:", 6) == 0)
1985 yield = (string_is_ip_address(s+6, NULL) == 4);
1987 yield = (string_is_ip_address(s+1, NULL) != 0);
1992 /* Non-literals must be alpha, dot, hyphen, plus any non-valid chars
1993 that have been configured (usually underscore - sigh). */
1996 for (yield = TRUE; *s; s++)
1997 if (!isalnum(*s) && *s != '.' && *s != '-' &&
1998 Ustrchr(helo_allow_chars, *s) == NULL)
2004 /* Save argument if OK */
2006 if (yield) sender_helo_name = string_copy_perm(start, TRUE);
2014 /*************************************************
2015 * Extract SMTP command option *
2016 *************************************************/
2018 /* This function picks the next option setting off the end of smtp_cmd_data. It
2019 is called for MAIL FROM and RCPT TO commands, to pick off the optional ESMTP
2020 things that can appear there.
2023 name point this at the name
2024 value point this at the data string
2026 Returns: TRUE if found an option
2030 extract_option(uschar **name, uschar **value)
2034 if (Ustrlen(smtp_cmd_data) <= 0) return FALSE;
2035 v = smtp_cmd_data + Ustrlen(smtp_cmd_data) - 1;
2036 while (v > smtp_cmd_data && isspace(*v)) v--;
2039 while (v > smtp_cmd_data && *v != '=' && !isspace(*v))
2041 /* Take care to not stop at a space embedded in a quoted local-part */
2044 do v--; while (v > smtp_cmd_data && *v != '"');
2045 if (v <= smtp_cmd_data) return FALSE;
2049 if (v <= smtp_cmd_data) return FALSE;
2054 while (n > smtp_cmd_data && isalpha(n[-1])) n--;
2055 /* RFC says SP, but TAB seen in wild and other major MTAs accept it */
2056 if (n <= smtp_cmd_data || !isspace(n[-1])) return FALSE;
2073 /*************************************************
2074 * Reset for new message *
2075 *************************************************/
2077 /* This function is called whenever the SMTP session is reset from
2078 within either of the setup functions; also from the daemon loop.
2080 Argument: the stacking pool storage reset point
2085 smtp_reset(void *reset_point)
2087 recipients_list = NULL;
2088 rcpt_count = rcpt_defer_count = rcpt_fail_count =
2089 raw_recipients_count = recipients_count = recipients_list_max = 0;
2090 message_linecount = 0;
2092 message_body = message_body_end = NULL;
2093 acl_added_headers = NULL;
2094 acl_removed_headers = NULL;
2095 f.queue_only_policy = FALSE;
2096 rcpt_smtp_response = NULL;
2097 fl.rcpt_smtp_response_same = TRUE;
2098 fl.rcpt_in_progress = FALSE;
2099 f.deliver_freeze = FALSE; /* Can be set by ACL */
2100 freeze_tell = freeze_tell_config; /* Can be set by ACL */
2101 fake_response = OK; /* Can be set by ACL */
2102 #ifdef WITH_CONTENT_SCAN
2103 f.no_mbox_unspool = FALSE; /* Can be set by ACL */
2105 f.submission_mode = FALSE; /* Can be set by ACL */
2106 f.suppress_local_fixups = f.suppress_local_fixups_default; /* Can be set by ACL */
2107 f.active_local_from_check = local_from_check; /* Can be set by ACL */
2108 f.active_local_sender_retain = local_sender_retain; /* Can be set by ACL */
2109 sending_ip_address = NULL;
2110 return_path = sender_address = NULL;
2111 deliver_localpart_data = deliver_domain_data =
2112 recipient_data = sender_data = NULL; /* Can be set by ACL */
2113 recipient_verify_failure = NULL;
2114 deliver_localpart_parent = deliver_localpart_orig = NULL;
2115 deliver_domain_parent = deliver_domain_orig = NULL;
2116 callout_address = NULL;
2117 submission_name = NULL; /* Can be set by ACL */
2118 raw_sender = NULL; /* After SMTP rewrite, before qualifying */
2119 sender_address_unrewritten = NULL; /* Set only after verify rewrite */
2120 sender_verified_list = NULL; /* No senders verified */
2121 memset(sender_address_cache, 0, sizeof(sender_address_cache));
2122 memset(sender_domain_cache, 0, sizeof(sender_domain_cache));
2124 authenticated_sender = NULL;
2125 #ifdef EXPERIMENTAL_BRIGHTMAIL
2127 bmi_verdicts = NULL;
2129 dnslist_domain = dnslist_matched = NULL;
2131 spf_header_comment = spf_received = spf_result = spf_smtp_comment = NULL;
2132 spf_result_guessed = FALSE;
2134 #ifndef DISABLE_DKIM
2135 dkim_cur_signer = dkim_signers =
2136 dkim_signing_domain = dkim_signing_selector = dkim_signatures = NULL;
2137 dkim_cur_signer = dkim_signers = dkim_signing_domain = dkim_signing_selector = NULL;
2138 f.dkim_disable_verify = FALSE;
2139 dkim_collect_input = 0;
2140 dkim_verify_overall = dkim_verify_status = dkim_verify_reason = NULL;
2141 dkim_key_length = 0;
2143 #ifdef SUPPORT_DMARC
2144 f.dmarc_has_been_checked = f.dmarc_disable_verify = f.dmarc_enable_forensic = FALSE;
2145 dmarc_domain_policy = dmarc_status = dmarc_status_text =
2146 dmarc_used_domain = NULL;
2148 #ifdef EXPERIMENTAL_ARC
2149 arc_state = arc_state_reason = NULL;
2150 arc_received_instance = 0;
2154 deliver_host = deliver_host_address = NULL; /* Can be set by ACL */
2155 #ifndef DISABLE_PRDR
2156 prdr_requested = FALSE;
2159 message_smtputf8 = FALSE;
2161 #ifdef WITH_CONTENT_SCAN
2164 body_linecount = body_zerocount = 0;
2166 lookup_value = NULL; /* Can be set by ACL */
2167 sender_rate = sender_rate_limit = sender_rate_period = NULL;
2168 ratelimiters_mail = NULL; /* Updated by ratelimit ACL condition */
2169 /* Note that ratelimiters_conn persists across resets. */
2171 /* Reset message ACL variables */
2175 /* Warning log messages are saved in malloc store. They are saved to avoid
2176 repetition in the same message, but it seems right to repeat them for different
2179 while (acl_warn_logged)
2181 string_item *this = acl_warn_logged;
2182 acl_warn_logged = acl_warn_logged->next;
2187 store_reset(reset_point);
2190 return store_mark();
2197 /*************************************************
2198 * Initialize for incoming batched SMTP message *
2199 *************************************************/
2201 /* This function is called from smtp_setup_msg() in the case when
2202 smtp_batched_input is true. This happens when -bS is used to pass a whole batch
2203 of messages in one file with SMTP commands between them. All errors must be
2204 reported by sending a message, and only MAIL FROM, RCPT TO, and DATA are
2205 relevant. After an error on a sender, or an invalid recipient, the remainder
2206 of the message is skipped. The value of received_protocol is already set.
2209 Returns: > 0 message successfully started (reached DATA)
2210 = 0 QUIT read or end of file reached
2211 < 0 should not occur
2215 smtp_setup_batch_msg(void)
2218 rmark reset_point = store_mark();
2220 /* Save the line count at the start of each transaction - single commands
2221 like HELO and RSET count as whole transactions. */
2223 bsmtp_transaction_linecount = receive_linecount;
2225 if ((receive_feof)()) return 0; /* Treat EOF as QUIT */
2227 cancel_cutthrough_connection(TRUE, US"smtp_setup_batch_msg");
2228 reset_point = smtp_reset(reset_point); /* Reset for start of message */
2230 /* Deal with SMTP commands. This loop is exited by setting done to a POSITIVE
2231 value. The values are 2 larger than the required yield of the function. */
2236 uschar *recipient = NULL;
2237 int start, end, sender_domain, recipient_domain;
2239 switch(smtp_read_command(FALSE, GETC_BUFFER_UNLIMITED))
2241 /* The HELO/EHLO commands set sender_address_helo if they have
2242 valid data; otherwise they are ignored, except that they do
2243 a reset of the state. */
2248 check_helo(smtp_cmd_data);
2252 cancel_cutthrough_connection(TRUE, US"RSET received");
2253 reset_point = smtp_reset(reset_point);
2254 bsmtp_transaction_linecount = receive_linecount;
2258 /* The MAIL FROM command requires an address as an operand. All we
2259 do here is to parse it for syntactic correctness. The form "<>" is
2260 a special case which converts into an empty string. The start/end
2261 pointers in the original are not used further for this address, as
2262 it is the canonical extracted address which is all that is kept. */
2265 smtp_mailcmd_count++; /* Count for no-mail log */
2267 /* The function moan_smtp_batch() does not return. */
2268 moan_smtp_batch(smtp_cmd_buffer, "503 Sender already given");
2270 if (smtp_cmd_data[0] == 0)
2271 /* The function moan_smtp_batch() does not return. */
2272 moan_smtp_batch(smtp_cmd_buffer, "501 MAIL FROM must have an address operand");
2274 /* Reset to start of message */
2276 cancel_cutthrough_connection(TRUE, US"MAIL received");
2277 reset_point = smtp_reset(reset_point);
2279 /* Apply SMTP rewrite */
2281 raw_sender = rewrite_existflags & rewrite_smtp
2282 /* deconst ok as smtp_cmd_data was not const */
2283 ? US rewrite_one(smtp_cmd_data, rewrite_smtp|rewrite_smtp_sender, NULL,
2284 FALSE, US"", global_rewrite_rules)
2287 /* Extract the address; the TRUE flag allows <> as valid */
2290 parse_extract_address(raw_sender, &errmess, &start, &end, &sender_domain,
2294 /* The function moan_smtp_batch() does not return. */
2295 moan_smtp_batch(smtp_cmd_buffer, "501 %s", errmess);
2297 sender_address = string_copy(raw_sender);
2299 /* Qualify unqualified sender addresses if permitted to do so. */
2302 && sender_address[0] != 0 && sender_address[0] != '@')
2303 if (f.allow_unqualified_sender)
2305 /* deconst ok as sender_address was not const */
2306 sender_address = US rewrite_address_qualify(sender_address, FALSE);
2307 DEBUG(D_receive) debug_printf("unqualified address %s accepted "
2308 "and rewritten\n", raw_sender);
2310 /* The function moan_smtp_batch() does not return. */
2312 moan_smtp_batch(smtp_cmd_buffer, "501 sender address must contain "
2317 /* The RCPT TO command requires an address as an operand. All we do
2318 here is to parse it for syntactic correctness. There may be any number
2319 of RCPT TO commands, specifying multiple senders. We build them all into
2320 a data structure that is in argc/argv format. The start/end values
2321 given by parse_extract_address are not used, as we keep only the
2322 extracted address. */
2325 if (!sender_address)
2326 /* The function moan_smtp_batch() does not return. */
2327 moan_smtp_batch(smtp_cmd_buffer, "503 No sender yet given");
2329 if (smtp_cmd_data[0] == 0)
2330 /* The function moan_smtp_batch() does not return. */
2331 moan_smtp_batch(smtp_cmd_buffer,
2332 "501 RCPT TO must have an address operand");
2334 /* Check maximum number allowed */
2336 if (recipients_max > 0 && recipients_count + 1 > recipients_max)
2337 /* The function moan_smtp_batch() does not return. */
2338 moan_smtp_batch(smtp_cmd_buffer, "%s too many recipients",
2339 recipients_max_reject? "552": "452");
2341 /* Apply SMTP rewrite, then extract address. Don't allow "<>" as a
2342 recipient address */
2344 recipient = rewrite_existflags & rewrite_smtp
2345 /* deconst ok as smtp_cmd_data was not const */
2346 ? US rewrite_one(smtp_cmd_data, rewrite_smtp, NULL, FALSE, US"",
2347 global_rewrite_rules)
2350 recipient = parse_extract_address(recipient, &errmess, &start, &end,
2351 &recipient_domain, FALSE);
2354 /* The function moan_smtp_batch() does not return. */
2355 moan_smtp_batch(smtp_cmd_buffer, "501 %s", errmess);
2357 /* If the recipient address is unqualified, qualify it if permitted. Then
2358 add it to the list of recipients. */
2360 if (!recipient_domain)
2361 if (f.allow_unqualified_recipient)
2363 DEBUG(D_receive) debug_printf("unqualified address %s accepted\n",
2365 /* deconst ok as recipient was not const */
2366 recipient = US rewrite_address_qualify(recipient, TRUE);
2368 /* The function moan_smtp_batch() does not return. */
2370 moan_smtp_batch(smtp_cmd_buffer,
2371 "501 recipient address must contain a domain");
2373 receive_add_recipient(recipient, -1);
2377 /* The DATA command is legal only if it follows successful MAIL FROM
2378 and RCPT TO commands. This function is complete when a valid DATA
2379 command is encountered. */
2382 if (!sender_address || recipients_count <= 0)
2383 /* The function moan_smtp_batch() does not return. */
2384 if (!sender_address)
2385 moan_smtp_batch(smtp_cmd_buffer,
2386 "503 MAIL FROM:<sender> command must precede DATA");
2388 moan_smtp_batch(smtp_cmd_buffer,
2389 "503 RCPT TO:<recipient> must precede DATA");
2392 done = 3; /* DATA successfully achieved */
2393 message_ended = END_NOTENDED; /* Indicate in middle of message */
2398 /* The VRFY, EXPN, HELP, ETRN, and NOOP commands are ignored. */
2405 bsmtp_transaction_linecount = receive_linecount;
2410 f.smtp_in_quit = TRUE;
2417 /* The function moan_smtp_batch() does not return. */
2418 moan_smtp_batch(smtp_cmd_buffer, "501 Unexpected argument data");
2423 /* The function moan_smtp_batch() does not return. */
2424 moan_smtp_batch(smtp_cmd_buffer, "501 Unexpected NULL in SMTP command");
2429 /* The function moan_smtp_batch() does not return. */
2430 moan_smtp_batch(smtp_cmd_buffer, "500 Command unrecognized");
2435 return done - 2; /* Convert yield values */
2443 smtp_log_tls_fail(const uschar * errstr)
2445 const uschar * conn_info = smtp_get_connection_info();
2447 if (Ustrncmp(conn_info, US"SMTP ", 5) == 0) conn_info += 5;
2448 /* I'd like to get separated H= here, but too hard for now */
2450 log_write(0, LOG_MAIN, "TLS error on %s %s", conn_info, errstr);
2464 socklen_t len = sizeof(is_fastopen);
2466 /* The tinfo TCPOPT_FAST_OPEN bit seems unreliable, and we don't see state
2467 TCP_SYN_RCV (as of 12.1) so no idea about data-use. */
2469 if (getsockopt(fileno(smtp_out), IPPROTO_TCP, TCP_FASTOPEN, &is_fastopen, &len) == 0)
2474 debug_printf("TFO mode connection (TCP_FASTOPEN getsockopt)\n");
2475 f.tcp_in_fastopen = TRUE;
2478 else DEBUG(D_receive)
2479 debug_printf("TCP_INFO getsockopt: %s\n", strerror(errno));
2481 # elif defined(TCP_INFO)
2482 struct tcp_info tinfo;
2483 socklen_t len = sizeof(tinfo);
2485 if (getsockopt(fileno(smtp_out), IPPROTO_TCP, TCP_INFO, &tinfo, &len) == 0)
2486 # ifdef TCPI_OPT_SYN_DATA /* FreeBSD 11,12 do not seem to have this yet */
2487 if (tinfo.tcpi_options & TCPI_OPT_SYN_DATA)
2490 debug_printf("TFO mode connection (ACKd data-on-SYN)\n");
2491 f.tcp_in_fastopen_data = f.tcp_in_fastopen = TRUE;
2495 if (tinfo.tcpi_state == TCP_SYN_RECV) /* Not seen on FreeBSD 12.1 */
2498 debug_printf("TFO mode connection (state TCP_SYN_RECV)\n");
2499 f.tcp_in_fastopen = TRUE;
2501 else DEBUG(D_receive)
2502 debug_printf("TCP_INFO getsockopt: %s\n", strerror(errno));
2509 log_connect_tls_drop(const uschar * what, const uschar * log_msg)
2511 gstring * g = s_tlslog(NULL);
2512 uschar * tls = string_from_gstring(g);
2514 log_write(L_connection_reject,
2515 log_reject_target, "%s%s%s dropped by %s%s%s",
2516 LOGGING(dnssec) && sender_host_dnssec ? US" DS" : US"",
2517 host_and_ident(TRUE),
2520 log_msg ? US": " : US"", log_msg);
2524 /*************************************************
2525 * Start an SMTP session *
2526 *************************************************/
2528 /* This function is called at the start of an SMTP session. Thereafter,
2529 smtp_setup_msg() is called to initiate each separate message. This
2530 function does host-specific testing, and outputs the banner line.
2533 Returns: FALSE if the session can not continue; something has
2534 gone wrong, or the connection to the host is blocked
2538 smtp_start_session(void)
2541 uschar *user_msg, *log_msg;
2546 gettimeofday(&smtp_connection_start, NULL);
2547 for (smtp_ch_index = 0; smtp_ch_index < SMTP_HBUFF_SIZE; smtp_ch_index++)
2548 smtp_connection_had[smtp_ch_index] = SCH_NONE;
2551 /* Default values for certain variables */
2553 fl.helo_seen = fl.esmtp = fl.helo_accept_junk = FALSE;
2554 smtp_mailcmd_count = 0;
2555 count_nonmail = TRUE_UNSET;
2556 synprot_error_count = unknown_command_count = nonmail_command_count = 0;
2557 smtp_delay_mail = smtp_rlm_base;
2558 fl.auth_advertised = FALSE;
2559 f.smtp_in_pipelining_advertised = f.smtp_in_pipelining_used = FALSE;
2560 f.pipelining_enable = TRUE;
2561 sync_cmd_limit = NON_SYNC_CMD_NON_PIPELINING;
2562 fl.smtp_exit_function_called = FALSE; /* For avoiding loop in not-quit exit */
2564 /* If receiving by -bs from a trusted user, or testing with -bh, we allow
2565 authentication settings from -oMaa to remain in force. */
2567 if (!host_checking && !f.sender_host_notsocket)
2568 sender_host_auth_pubname = sender_host_authenticated = NULL;
2569 authenticated_by = NULL;
2572 tls_in.ver = tls_in.cipher = tls_in.peerdn = NULL;
2573 tls_in.ourcert = tls_in.peercert = NULL;
2575 tls_in.ocsp = OCSP_NOT_REQ;
2576 fl.tls_advertised = FALSE;
2578 fl.dsn_advertised = FALSE;
2580 fl.smtputf8_advertised = FALSE;
2583 /* Reset ACL connection variables */
2587 /* Allow for trailing 0 in the command and data buffers. Tainted. */
2589 smtp_cmd_buffer = store_get_perm(2*SMTP_CMD_BUFFER_SIZE + 2, GET_TAINTED);
2591 smtp_cmd_buffer[0] = 0;
2592 smtp_data_buffer = smtp_cmd_buffer + SMTP_CMD_BUFFER_SIZE + 1;
2594 /* For batched input, the protocol setting can be overridden from the
2595 command line by a trusted caller. */
2597 if (smtp_batched_input)
2599 if (!received_protocol) received_protocol = US"local-bsmtp";
2602 /* For non-batched SMTP input, the protocol setting is forced here. It will be
2603 reset later if any of EHLO/AUTH/STARTTLS are received. */
2607 (sender_host_address ? protocols : protocols_local) [pnormal];
2609 /* Set up the buffer for inputting using direct read() calls, and arrange to
2610 call the local functions instead of the standard C ones. */
2614 receive_getc = smtp_getc;
2615 receive_getbuf = smtp_getbuf;
2616 receive_get_cache = smtp_get_cache;
2617 receive_hasc = smtp_hasc;
2618 receive_ungetc = smtp_ungetc;
2619 receive_feof = smtp_feof;
2620 receive_ferror = smtp_ferror;
2621 lwr_receive_getc = NULL;
2622 lwr_receive_getbuf = NULL;
2623 lwr_receive_hasc = NULL;
2624 lwr_receive_ungetc = NULL;
2626 /* Set up the message size limit; this may be host-specific */
2628 thismessage_size_limit = expand_string_integer(message_size_limit, TRUE);
2629 if (expand_string_message)
2631 if (thismessage_size_limit == -1)
2632 log_write(0, LOG_MAIN|LOG_PANIC, "unable to expand message_size_limit: "
2633 "%s", expand_string_message);
2635 log_write(0, LOG_MAIN|LOG_PANIC, "invalid message_size_limit: "
2636 "%s", expand_string_message);
2637 smtp_closedown(US"Temporary local problem - please try later");
2641 /* When a message is input locally via the -bs or -bS options, sender_host_
2642 unknown is set unless -oMa was used to force an IP address, in which case it
2643 is checked like a real remote connection. When -bs is used from inetd, this
2644 flag is not set, causing the sending host to be checked. The code that deals
2645 with IP source routing (if configured) is never required for -bs or -bS and
2646 the flag sender_host_notsocket is used to suppress it.
2648 If smtp_accept_max and smtp_accept_reserve are set, keep some connections in
2649 reserve for certain hosts and/or networks. */
2651 if (!f.sender_host_unknown)
2654 BOOL reserved_host = FALSE;
2656 /* Look up IP options (source routing info) on the socket if this is not an
2657 -oMa "host", and if any are found, log them and drop the connection.
2659 Linux (and others now, see below) is different to everyone else, so there
2660 has to be some conditional compilation here. Versions of Linux before 2.1.15
2661 used a structure whose name was "options". Somebody finally realized that
2662 this name was silly, and it got changed to "ip_options". I use the
2663 newer name here, but there is a fudge in the script that sets up os.h
2664 to define a macro in older Linux systems.
2666 Sigh. Linux is a fast-moving target. Another generation of Linux uses
2667 glibc 2, which has chosen ip_opts for the structure name. This is now
2668 really a glibc thing rather than a Linux thing, so the condition name
2669 has been changed to reflect this. It is relevant also to GNU/Hurd.
2671 Mac OS 10.x (Darwin) is like the later glibc versions, but without the
2672 setting of the __GLIBC__ macro, so we can't detect it automatically. There's
2673 a special macro defined in the os.h file.
2675 Some DGUX versions on older hardware appear not to support IP options at
2676 all, so there is now a general macro which can be set to cut out this
2679 How to do this properly in IPv6 is not yet known. */
2681 #if !HAVE_IPV6 && !defined(NO_IP_OPTIONS)
2683 # ifdef GLIBC_IP_OPTIONS
2684 # if (!defined __GLIBC__) || (__GLIBC__ < 2)
2689 # elif defined DARWIN_IP_OPTIONS
2695 if (!host_checking && !f.sender_host_notsocket)
2698 EXIM_SOCKLEN_T optlen = sizeof(struct ip_options) + MAX_IPOPTLEN;
2699 struct ip_options *ipopt = store_get(optlen, GET_UNTAINTED);
2700 # elif OPTSTYLE == 2
2701 struct ip_opts ipoptblock;
2702 struct ip_opts *ipopt = &ipoptblock;
2703 EXIM_SOCKLEN_T optlen = sizeof(ipoptblock);
2705 struct ipoption ipoptblock;
2706 struct ipoption *ipopt = &ipoptblock;
2707 EXIM_SOCKLEN_T optlen = sizeof(ipoptblock);
2710 /* Occasional genuine failures of getsockopt() have been seen - for
2711 example, "reset by peer". Therefore, just log and give up on this
2712 call, unless the error is ENOPROTOOPT. This error is given by systems
2713 that have the interfaces but not the mechanism - e.g. GNU/Hurd at the time
2714 of writing. So for that error, carry on - we just can't do an IP options
2717 DEBUG(D_receive) debug_printf("checking for IP options\n");
2719 if (getsockopt(fileno(smtp_out), IPPROTO_IP, IP_OPTIONS, US (ipopt),
2722 if (errno != ENOPROTOOPT)
2724 log_write(0, LOG_MAIN, "getsockopt() failed from %s: %s",
2725 host_and_ident(FALSE), strerror(errno));
2726 smtp_printf("451 SMTP service not available\r\n", FALSE);
2731 /* Deal with any IP options that are set. On the systems I have looked at,
2732 the value of MAX_IPOPTLEN has been 40, meaning that there should never be
2733 more logging data than will fit in big_buffer. Nevertheless, after somebody
2734 questioned this code, I've added in some paranoid checking. */
2736 else if (optlen > 0)
2738 uschar * p = big_buffer;
2739 uschar * pend = big_buffer + big_buffer_size;
2742 struct in_addr addr;
2745 uschar * optstart = US (ipopt->__data);
2746 # elif OPTSTYLE == 2
2747 uschar * optstart = US (ipopt->ip_opts);
2749 uschar * optstart = US (ipopt->ipopt_list);
2752 DEBUG(D_receive) debug_printf("IP options exist\n");
2754 Ustrcpy(p, "IP options on incoming call:");
2757 for (uschar * opt = optstart; opt && opt < US (ipopt) + optlen; )
2772 string_format(p, pend-p, " %s [@%s",
2773 (*opt == IPOPT_SSRR)? "SSRR" : "LSRR",
2774 inet_ntoa(*((struct in_addr *)(&(ipopt->faddr)))))
2775 # elif OPTSTYLE == 2
2776 string_format(p, pend-p, " %s [@%s",
2777 (*opt == IPOPT_SSRR)? "SSRR" : "LSRR",
2778 inet_ntoa(ipopt->ip_dst))
2780 string_format(p, pend-p, " %s [@%s",
2781 (*opt == IPOPT_SSRR)? "SSRR" : "LSRR",
2782 inet_ntoa(ipopt->ipopt_dst))
2791 optcount = (opt[1] - 3) / sizeof(struct in_addr);
2793 while (optcount-- > 0)
2795 memcpy(&addr, adptr, sizeof(addr));
2796 if (!string_format(p, pend - p - 1, "%s%s",
2797 (optcount == 0)? ":" : "@", inet_ntoa(addr)))
2803 adptr += sizeof(struct in_addr);
2811 if (pend - p < 4 + 3*opt[1]) { opt = NULL; break; }
2814 for (int i = 0; i < opt[1]; i++)
2815 p += sprintf(CS p, "%2.2x ", opt[i]);
2823 log_write(0, LOG_MAIN, "%s", big_buffer);
2825 /* Refuse any call with IP options. This is what tcpwrappers 7.5 does. */
2827 log_write(0, LOG_MAIN|LOG_REJECT,
2828 "connection from %s refused (IP options)", host_and_ident(FALSE));
2830 smtp_printf("554 SMTP service not available\r\n", FALSE);
2834 /* Length of options = 0 => there are no options */
2836 else DEBUG(D_receive) debug_printf("no IP options found\n");
2838 #endif /* HAVE_IPV6 && !defined(NO_IP_OPTIONS) */
2840 /* Set keep-alive in socket options. The option is on by default. This
2841 setting is an attempt to get rid of some hanging connections that stick in
2842 read() when the remote end (usually a dialup) goes away. */
2844 if (smtp_accept_keepalive && !f.sender_host_notsocket)
2845 ip_keepalive(fileno(smtp_out), sender_host_address, FALSE);
2847 /* If the current host matches host_lookup, set the name by doing a
2848 reverse lookup. On failure, sender_host_name will be NULL and
2849 host_lookup_failed will be TRUE. This may or may not be serious - optional
2852 if (verify_check_host(&host_lookup) == OK)
2854 (void)host_name_lookup();
2855 host_build_sender_fullhost();
2858 /* Delay this until we have the full name, if it is looked up. */
2860 set_process_info("handling incoming connection from %s",
2861 host_and_ident(FALSE));
2863 /* Expand smtp_receive_timeout, if needed */
2865 if (smtp_receive_timeout_s)
2868 if ( !(exp = expand_string(smtp_receive_timeout_s))
2870 || (smtp_receive_timeout = readconf_readtime(exp, 0, FALSE)) < 0
2872 log_write(0, LOG_MAIN|LOG_PANIC,
2873 "bad value for smtp_receive_timeout: '%s'", exp ? exp : US"");
2876 /* Test for explicit connection rejection */
2878 if (verify_check_host(&host_reject_connection) == OK)
2880 log_write(L_connection_reject, LOG_MAIN|LOG_REJECT, "refused connection "
2881 "from %s (host_reject_connection)", host_and_ident(FALSE));
2883 if (!tls_in.on_connect)
2885 smtp_printf("554 SMTP service not available\r\n", FALSE);
2889 /* Test with TCP Wrappers if so configured. There is a problem in that
2890 hosts_ctl() returns 0 (deny) under a number of system failure circumstances,
2891 such as disks dying. In these cases, it is desirable to reject with a 4xx
2892 error instead of a 5xx error. There isn't a "right" way to detect such
2893 problems. The following kludge is used: errno is zeroed before calling
2894 hosts_ctl(). If the result is "reject", a 5xx error is given only if the
2895 value of errno is 0 or ENOENT (which happens if /etc/hosts.{allow,deny} does
2898 #ifdef USE_TCP_WRAPPERS
2900 if (!(tcp_wrappers_name = expand_string(tcp_wrappers_daemon_name)))
2901 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "Expansion of \"%s\" "
2902 "(tcp_wrappers_name) failed: %s", string_printing(tcp_wrappers_name),
2903 expand_string_message);
2905 if (!hosts_ctl(tcp_wrappers_name,
2906 sender_host_name ? CS sender_host_name : STRING_UNKNOWN,
2907 sender_host_address ? CS sender_host_address : STRING_UNKNOWN,
2908 sender_ident ? CS sender_ident : STRING_UNKNOWN))
2910 if (errno == 0 || errno == ENOENT)
2912 HDEBUG(D_receive) debug_printf("tcp wrappers rejection\n");
2913 log_write(L_connection_reject,
2914 LOG_MAIN|LOG_REJECT, "refused connection from %s "
2915 "(tcp wrappers)", host_and_ident(FALSE));
2916 smtp_printf("554 SMTP service not available\r\n", FALSE);
2920 int save_errno = errno;
2921 HDEBUG(D_receive) debug_printf("tcp wrappers rejected with unexpected "
2922 "errno value %d\n", save_errno);
2923 log_write(L_connection_reject,
2924 LOG_MAIN|LOG_REJECT, "temporarily refused connection from %s "
2925 "(tcp wrappers errno=%d)", host_and_ident(FALSE), save_errno);
2926 smtp_printf("451 Temporary local problem - please try later\r\n", FALSE);
2932 /* Check for reserved slots. The value of smtp_accept_count has already been
2933 incremented to include this process. */
2935 if (smtp_accept_max > 0 &&
2936 smtp_accept_count > smtp_accept_max - smtp_accept_reserve)
2938 if ((rc = verify_check_host(&smtp_reserve_hosts)) != OK)
2940 log_write(L_connection_reject,
2941 LOG_MAIN, "temporarily refused connection from %s: not in "
2942 "reserve list: connected=%d max=%d reserve=%d%s",
2943 host_and_ident(FALSE), smtp_accept_count - 1, smtp_accept_max,
2944 smtp_accept_reserve, (rc == DEFER)? " (lookup deferred)" : "");
2945 smtp_printf("421 %s: Too many concurrent SMTP connections; "
2946 "please try again later\r\n", FALSE, smtp_active_hostname);
2949 reserved_host = TRUE;
2952 /* If a load level above which only messages from reserved hosts are
2953 accepted is set, check the load. For incoming calls via the daemon, the
2954 check is done in the superior process if there are no reserved hosts, to
2955 save a fork. In all cases, the load average will already be available
2956 in a global variable at this point. */
2958 if (smtp_load_reserve >= 0 &&
2959 load_average > smtp_load_reserve &&
2961 verify_check_host(&smtp_reserve_hosts) != OK)
2963 log_write(L_connection_reject,
2964 LOG_MAIN, "temporarily refused connection from %s: not in "
2965 "reserve list and load average = %.2f", host_and_ident(FALSE),
2966 (double)load_average/1000.0);
2967 smtp_printf("421 %s: Too much load; please try again later\r\n", FALSE,
2968 smtp_active_hostname);
2972 /* Determine whether unqualified senders or recipients are permitted
2973 for this host. Unfortunately, we have to do this every time, in order to
2974 set the flags so that they can be inspected when considering qualifying
2975 addresses in the headers. For a site that permits no qualification, this
2976 won't take long, however. */
2978 f.allow_unqualified_sender =
2979 verify_check_host(&sender_unqualified_hosts) == OK;
2981 f.allow_unqualified_recipient =
2982 verify_check_host(&recipient_unqualified_hosts) == OK;
2984 /* Determine whether HELO/EHLO is required for this host. The requirement
2985 can be hard or soft. */
2987 fl.helo_verify_required = verify_check_host(&helo_verify_hosts) == OK;
2988 if (!fl.helo_verify_required)
2989 fl.helo_verify = verify_check_host(&helo_try_verify_hosts) == OK;
2991 /* Determine whether this hosts is permitted to send syntactic junk
2992 after a HELO or EHLO command. */
2994 fl.helo_accept_junk = verify_check_host(&helo_accept_junk_hosts) == OK;
2997 /* For batch SMTP input we are now done. */
2999 if (smtp_batched_input) return TRUE;
3001 /* If valid Proxy Protocol source is connecting, set up session.
3002 Failure will not allow any SMTP function other than QUIT. */
3004 #ifdef SUPPORT_PROXY
3005 proxy_session = FALSE;
3006 f.proxy_session_failed = FALSE;
3007 if (check_proxy_protocol_host())
3008 setup_proxy_protocol_host();
3011 /* Run the connect ACL if it exists */
3014 if (acl_smtp_connect)
3017 if ((rc = acl_check(ACL_WHERE_CONNECT, NULL, acl_smtp_connect, &user_msg,
3021 if (tls_in.on_connect)
3022 log_connect_tls_drop(US"'connect' ACL", log_msg);
3025 (void) smtp_handle_acl_fail(ACL_WHERE_CONNECT, rc, user_msg, log_msg);
3030 /* Start up TLS if tls_on_connect is set. This is for supporting the legacy
3031 smtps port for use with older style SSL MTAs. */
3034 if (tls_in.on_connect)
3036 if (tls_server_start(&user_msg) != OK)
3037 return smtp_log_tls_fail(user_msg);
3038 cmd_list[CMD_LIST_TLS_AUTH].is_mail_cmd = TRUE;
3042 /* Output the initial message for a two-way SMTP connection. It may contain
3043 newlines, which then cause a multi-line response to be given. */
3045 code = US"220"; /* Default status code */
3046 esc = US""; /* Default extended status code */
3047 esclen = 0; /* Length of esc */
3053 smtp_message_code(&code, &codelen, &s, NULL, TRUE);
3057 esclen = codelen - 4;
3060 else if (!(s = expand_string(smtp_banner)))
3062 log_write(0, f.expand_string_forcedfail ? LOG_MAIN : LOG_MAIN|LOG_PANIC_DIE,
3063 "Expansion of \"%s\" (smtp_banner) failed: %s",
3064 smtp_banner, expand_string_message);
3065 /* for force-fail */
3067 if (tls_in.on_connect) tls_close(NULL, TLS_SHUTDOWN_WAIT);
3072 /* Remove any terminating newlines; might as well remove trailing space too */
3075 while (p > s && isspace(p[-1])) p--;
3076 s = string_copyn(s, p-s);
3078 /* It seems that CC:Mail is braindead, and assumes that the greeting message
3079 is all contained in a single IP packet. The original code wrote out the
3080 greeting using several calls to fprint/fputc, and on busy servers this could
3081 cause it to be split over more than one packet - which caused CC:Mail to fall
3082 over when it got the second part of the greeting after sending its first
3083 command. Sigh. To try to avoid this, build the complete greeting message
3084 first, and output it in one fell swoop. This gives a better chance of it
3085 ending up as a single packet. */
3087 ss = string_get(256);
3090 do /* At least once, in case we have an empty string */
3093 uschar *linebreak = Ustrchr(p, '\n');
3094 ss = string_catn(ss, code, 3);
3098 ss = string_catn(ss, US" ", 1);
3102 len = linebreak - p;
3103 ss = string_catn(ss, US"-", 1);
3105 ss = string_catn(ss, esc, esclen);
3106 ss = string_catn(ss, p, len);
3107 ss = string_catn(ss, US"\r\n", 2);
3113 /* Before we write the banner, check that there is no input pending, unless
3114 this synchronisation check is disabled. */
3116 #ifndef DISABLE_PIPE_CONNECT
3117 fl.pipe_connect_acceptable =
3118 sender_host_address && verify_check_host(&pipe_connect_advertise_hosts) == OK;
3121 if (fl.pipe_connect_acceptable)
3122 f.smtp_in_early_pipe_used = TRUE;
3128 unsigned n = smtp_inend - smtp_inptr;
3129 if (n > 128) n = 128;
3131 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP protocol "
3132 "synchronization error (input sent without waiting for greeting): "
3133 "rejected connection from %s input=\"%s\"", host_and_ident(TRUE),
3134 string_printing(string_copyn(smtp_inptr, n)));
3135 smtp_printf("554 SMTP synchronization error\r\n", FALSE);
3139 /* Now output the banner */
3140 /*XXX the ehlo-resp code does its own tls/nontls bit. Maybe subroutine that? */
3143 #ifndef DISABLE_PIPE_CONNECT
3144 fl.pipe_connect_acceptable && pipeline_connect_sends(),
3148 string_from_gstring(ss));
3150 /* Attempt to see if we sent the banner before the last ACK of the 3-way
3151 handshake arrived. If so we must have managed a TFO. */
3154 if (sender_host_address && !f.sender_host_notsocket) tfo_in_check();
3164 /*************************************************
3165 * Handle SMTP syntax and protocol errors *
3166 *************************************************/
3168 /* Write to the log for SMTP syntax errors in incoming commands, if configured
3169 to do so. Then transmit the error response. The return value depends on the
3170 number of syntax and protocol errors in this SMTP session.
3173 type error type, given as a log flag bit
3174 code response code; <= 0 means don't send a response
3175 data data to reflect in the response (can be NULL)
3176 errmess the error message
3178 Returns: -1 limit of syntax/protocol errors NOT exceeded
3179 +1 limit of syntax/protocol errors IS exceeded
3181 These values fit in with the values of the "done" variable in the main
3182 processing loop in smtp_setup_msg(). */
3185 synprot_error(int type, int code, uschar *data, uschar *errmess)
3189 log_write(type, LOG_MAIN, "SMTP %s error in \"%s\" %s %s",
3190 type == L_smtp_syntax_error ? "syntax" : "protocol",
3191 string_printing(smtp_cmd_buffer), host_and_ident(TRUE), errmess);
3193 if (++synprot_error_count > smtp_max_synprot_errors)
3196 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
3197 "syntax or protocol errors (last command was \"%s\", %s)",
3198 host_and_ident(FALSE), string_printing(smtp_cmd_buffer),
3199 string_from_gstring(s_connhad_log(NULL))
3205 smtp_printf("%d%c%s%s%s\r\n", FALSE, code, yield == 1 ? '-' : ' ',
3206 data ? data : US"", data ? US": " : US"", errmess);
3208 smtp_printf("%d Too many syntax or protocol errors\r\n", FALSE, code);
3217 /*************************************************
3218 * Send SMTP response, possibly multiline *
3219 *************************************************/
3221 /* There are, it seems, broken clients out there that cannot handle multiline
3222 responses. If no_multiline_responses is TRUE (it can be set from an ACL), we
3223 output nothing for non-final calls, and only the first line for anything else.
3226 code SMTP code, may involve extended status codes
3227 codelen length of smtp code; if > 4 there's an ESC
3228 final FALSE if the last line isn't the final line
3229 msg message text, possibly containing newlines
3235 smtp_respond(uschar* code, int codelen, BOOL final, uschar *msg)
3240 if (!final && f.no_multiline_responses) return;
3245 esclen = codelen - 4;
3248 /* If this is the first output for a (non-batch) RCPT command, see if all RCPTs
3249 have had the same. Note: this code is also present in smtp_printf(). It would
3250 be tidier to have it only in one place, but when it was added, it was easier to
3251 do it that way, so as not to have to mess with the code for the RCPT command,
3252 which sometimes uses smtp_printf() and sometimes smtp_respond(). */
3254 if (fl.rcpt_in_progress)
3256 if (!rcpt_smtp_response)
3257 rcpt_smtp_response = string_copy(msg);
3258 else if (fl.rcpt_smtp_response_same &&
3259 Ustrcmp(rcpt_smtp_response, msg) != 0)
3260 fl.rcpt_smtp_response_same = FALSE;
3261 fl.rcpt_in_progress = FALSE;
3264 /* Now output the message, splitting it up into multiple lines if necessary.
3265 We only handle pipelining these responses as far as nonfinal/final groups,
3266 not the whole MAIL/RCPT/DATA response set. */
3270 uschar *nl = Ustrchr(msg, '\n');
3273 smtp_printf("%.3s%c%.*s%s\r\n", !final, code, final ? ' ':'-', esclen, esc, msg);
3276 else if (nl[1] == 0 || f.no_multiline_responses)
3278 smtp_printf("%.3s%c%.*s%.*s\r\n", !final, code, final ? ' ':'-', esclen, esc,
3279 (int)(nl - msg), msg);
3284 smtp_printf("%.3s-%.*s%.*s\r\n", TRUE, code, esclen, esc, (int)(nl - msg), msg);
3286 Uskip_whitespace(&msg);
3294 /*************************************************
3295 * Parse user SMTP message *
3296 *************************************************/
3298 /* This function allows for user messages overriding the response code details
3299 by providing a suitable response code string at the start of the message
3300 user_msg. Check the message for starting with a response code and optionally an
3301 extended status code. If found, check that the first digit is valid, and if so,
3302 change the code pointer and length to use the replacement. An invalid code
3303 causes a panic log; in this case, if the log messages is the same as the user
3304 message, we must also adjust the value of the log message to show the code that
3305 is actually going to be used (the original one).
3307 This function is global because it is called from receive.c as well as within
3310 Note that the code length returned includes the terminating whitespace
3311 character, which is always included in the regex match.
3314 code SMTP code, may involve extended status codes
3315 codelen length of smtp code; if > 4 there's an ESC
3317 log_msg optional log message, to be adjusted with the new SMTP code
3318 check_valid if true, verify the response code
3324 smtp_message_code(uschar **code, int *codelen, uschar **msg, uschar **log_msg,
3330 if (!msg || !*msg || !regex_match(regex_smtp_code, *msg, -1, &match))
3333 len = Ustrlen(match);
3334 if (check_valid && (*msg)[0] != (*code)[0])
3336 log_write(0, LOG_MAIN|LOG_PANIC, "configured error code starts with "
3337 "incorrect digit (expected %c) in \"%s\"", (*code)[0], *msg);
3338 if (log_msg && *log_msg == *msg)
3339 *log_msg = string_sprintf("%s %s", *code, *log_msg + len);
3344 *codelen = len; /* Includes final space */
3346 *msg += len; /* Chop the code off the message */
3353 /*************************************************
3354 * Handle an ACL failure *
3355 *************************************************/
3357 /* This function is called when acl_check() fails. As well as calls from within
3358 this module, it is called from receive.c for an ACL after DATA. It sorts out
3359 logging the incident, and sends the error response. A message containing
3360 newlines is turned into a multiline SMTP response, but for logging, only the
3363 There's a table of default permanent failure response codes to use in
3364 globals.c, along with the table of names. VFRY is special. Despite RFC1123 it
3365 defaults disabled in Exim. However, discussion in connection with RFC 821bis
3366 (aka RFC 2821) has concluded that the response should be 252 in the disabled
3367 state, because there are broken clients that try VRFY before RCPT. A 5xx
3368 response should be given only when the address is positively known to be
3369 undeliverable. Sigh. We return 252 if there is no VRFY ACL or it provides
3370 no explicit code, but if there is one we let it know best.
3371 Also, for ETRN, 458 is given on refusal, and for AUTH, 503.
3373 From Exim 4.63, it is possible to override the response code details by
3374 providing a suitable response code string at the start of the message provided
3375 in user_msg. The code's first digit is checked for validity.
3378 where where the ACL was called from
3380 user_msg a message that can be included in an SMTP response
3381 log_msg a message for logging
3383 Returns: 0 in most cases
3384 2 if the failure code was FAIL_DROP, in which case the
3385 SMTP connection should be dropped (this value fits with the
3386 "done" variable in smtp_setup_msg() below)
3390 smtp_handle_acl_fail(int where, int rc, uschar *user_msg, uschar *log_msg)
3392 BOOL drop = rc == FAIL_DROP;
3396 uschar *sender_info = US"";
3399 if (drop) rc = FAIL;
3401 /* Set the default SMTP code, and allow a user message to change it. */
3403 smtp_code = rc == FAIL ? acl_wherecodes[where] : US"451";
3404 smtp_message_code(&smtp_code, &codelen, &user_msg, &log_msg,
3405 where != ACL_WHERE_VRFY);
3407 /* We used to have sender_address here; however, there was a bug that was not
3408 updating sender_address after a rewrite during a verify. When this bug was
3409 fixed, sender_address at this point became the rewritten address. I'm not sure
3410 this is what should be logged, so I've changed to logging the unrewritten
3411 address to retain backward compatibility. */
3415 #ifdef WITH_CONTENT_SCAN
3416 case ACL_WHERE_MIME: what = US"during MIME ACL checks"; break;
3418 case ACL_WHERE_PREDATA: what = US"DATA"; break;
3419 case ACL_WHERE_DATA: what = US"after DATA"; break;
3420 #ifndef DISABLE_PRDR
3421 case ACL_WHERE_PRDR: what = US"after DATA PRDR"; break;
3425 uschar * place = smtp_cmd_data ? smtp_cmd_data : US"in \"connect\" ACL";
3428 if (where == ACL_WHERE_AUTH) /* avoid logging auth creds */
3431 for (s = smtp_cmd_data; *s && !isspace(*s); ) s++;
3432 lim = s - smtp_cmd_data; /* atop after method */
3434 what = string_sprintf("%s %.*s", acl_wherenames[where], lim, place);
3439 case ACL_WHERE_RCPT:
3440 case ACL_WHERE_DATA:
3441 #ifdef WITH_CONTENT_SCAN
3442 case ACL_WHERE_MIME:
3444 sender_info = string_sprintf("F=<%s>%s%s%s%s ",
3445 sender_address_unrewritten ? sender_address_unrewritten : sender_address,
3446 sender_host_authenticated ? US" A=" : US"",
3447 sender_host_authenticated ? sender_host_authenticated : US"",
3448 sender_host_authenticated && authenticated_id ? US":" : US"",
3449 sender_host_authenticated && authenticated_id ? authenticated_id : US""
3454 /* If there's been a sender verification failure with a specific message, and
3455 we have not sent a response about it yet, do so now, as a preliminary line for
3456 failures, but not defers. However, always log it for defer, and log it for fail
3457 unless the sender_verify_fail log selector has been turned off. */
3459 if (sender_verified_failed &&
3460 !testflag(sender_verified_failed, af_sverify_told))
3462 BOOL save_rcpt_in_progress = fl.rcpt_in_progress;
3463 fl.rcpt_in_progress = FALSE; /* So as not to treat these as the error */
3465 setflag(sender_verified_failed, af_sverify_told);
3467 if (rc != FAIL || LOGGING(sender_verify_fail))
3468 log_write(0, LOG_MAIN|LOG_REJECT, "%s sender verify %s for <%s>%s",
3469 host_and_ident(TRUE),
3470 ((sender_verified_failed->special_action & 255) == DEFER)? "defer":"fail",
3471 sender_verified_failed->address,
3472 (sender_verified_failed->message == NULL)? US"" :
3473 string_sprintf(": %s", sender_verified_failed->message));
3475 if (rc == FAIL && sender_verified_failed->user_message)
3476 smtp_respond(smtp_code, codelen, FALSE, string_sprintf(
3477 testflag(sender_verified_failed, af_verify_pmfail)?
3478 "Postmaster verification failed while checking <%s>\n%s\n"
3479 "Several RFCs state that you are required to have a postmaster\n"
3480 "mailbox for each mail domain. This host does not accept mail\n"
3481 "from domains whose servers reject the postmaster address."
3483 testflag(sender_verified_failed, af_verify_nsfail)?
3484 "Callback setup failed while verifying <%s>\n%s\n"
3485 "The initial connection, or a HELO or MAIL FROM:<> command was\n"
3486 "rejected. Refusing MAIL FROM:<> does not help fight spam, disregards\n"
3487 "RFC requirements, and stops you from receiving standard bounce\n"
3488 "messages. This host does not accept mail from domains whose servers\n"
3491 "Verification failed for <%s>\n%s",
3492 sender_verified_failed->address,
3493 sender_verified_failed->user_message));
3495 fl.rcpt_in_progress = save_rcpt_in_progress;
3498 /* Sort out text for logging */
3500 log_msg = log_msg ? string_sprintf(": %s", log_msg) : US"";
3501 if ((lognl = Ustrchr(log_msg, '\n'))) *lognl = 0;
3503 /* Send permanent failure response to the command, but the code used isn't
3504 always a 5xx one - see comments at the start of this function. If the original
3505 rc was FAIL_DROP we drop the connection and yield 2. */
3508 smtp_respond(smtp_code, codelen, TRUE,
3509 user_msg ? user_msg : US"Administrative prohibition");
3511 /* Send temporary failure response to the command. Don't give any details,
3512 unless acl_temp_details is set. This is TRUE for a callout defer, a "defer"
3513 verb, and for a header verify when smtp_return_error_details is set.
3515 This conditional logic is all somewhat of a mess because of the odd
3516 interactions between temp_details and return_error_details. One day it should
3517 be re-implemented in a tidier fashion. */
3520 if (f.acl_temp_details && user_msg)
3522 if ( smtp_return_error_details
3523 && sender_verified_failed
3524 && sender_verified_failed->message
3526 smtp_respond(smtp_code, codelen, FALSE, sender_verified_failed->message);
3528 smtp_respond(smtp_code, codelen, TRUE, user_msg);
3531 smtp_respond(smtp_code, codelen, TRUE,
3532 US"Temporary local problem - please try later");
3534 /* Log the incident to the logs that are specified by log_reject_target
3535 (default main, reject). This can be empty to suppress logging of rejections. If
3536 the connection is not forcibly to be dropped, return 0. Otherwise, log why it
3537 is closing if required and return 2. */
3539 if (log_reject_target != 0)
3542 gstring * g = s_tlslog(NULL);
3543 uschar * tls = string_from_gstring(g);
3544 if (!tls) tls = US"";
3546 uschar * tls = US"";
3548 log_write(where == ACL_WHERE_CONNECT ? L_connection_reject : 0,
3549 log_reject_target, "%s%s%s %s%srejected %s%s",
3550 LOGGING(dnssec) && sender_host_dnssec ? US" DS" : US"",
3551 host_and_ident(TRUE),
3554 rc == FAIL ? US"" : US"temporarily ",
3558 if (!drop) return 0;
3560 log_write(L_smtp_connection, LOG_MAIN, "%s closed by DROP in ACL",
3561 smtp_get_connection_info());
3563 /* Run the not-quit ACL, but without any custom messages. This should not be a
3564 problem, because we get here only if some other ACL has issued "drop", and
3565 in that case, *its* custom messages will have been used above. */
3567 smtp_notquit_exit(US"acl-drop", NULL, NULL);
3569 /* An overenthusiastic fail2ban/iptables implimentation has been seen to result
3570 in the TCP conn staying open, and retrying, despite this process exiting. A
3571 malicious client could possibly do the same, tying up server netowrking
3572 resources. Close the socket explicitly to try to avoid that (there's a note in
3573 the Linux socket(7) manpage, SO_LINGER para, to the effect that exim() without
3574 close() results in the socket always lingering). */
3576 (void) poll_one_fd(fileno(smtp_in), POLLIN, 200);
3577 DEBUG(D_any) debug_printf_indent("SMTP(close)>>\n");
3578 (void) fclose(smtp_in);
3579 (void) fclose(smtp_out);
3587 /*************************************************
3588 * Handle SMTP exit when QUIT is not given *
3589 *************************************************/
3591 /* This function provides a logging/statistics hook for when an SMTP connection
3592 is dropped on the floor or the other end goes away. It's a global function
3593 because it's called from receive.c as well as this module. As well as running
3594 the NOTQUIT ACL, if there is one, this function also outputs a final SMTP
3595 response, either with a custom message from the ACL, or using a default. There
3596 is one case, however, when no message is output - after "drop". In that case,
3597 the ACL that obeyed "drop" has already supplied the custom message, and NULL is
3598 passed to this function.
3600 In case things go wrong while processing this function, causing an error that
3601 may re-enter this function, there is a recursion check.
3604 reason What $smtp_notquit_reason will be set to in the ACL;
3605 if NULL, the ACL is not run
3606 code The error code to return as part of the response
3607 defaultrespond The default message if there's no user_msg
3613 smtp_notquit_exit(uschar *reason, uschar *code, uschar *defaultrespond, ...)
3616 uschar *user_msg = NULL;
3617 uschar *log_msg = NULL;
3619 /* Check for recursive call */
3621 if (fl.smtp_exit_function_called)
3623 log_write(0, LOG_PANIC, "smtp_notquit_exit() called more than once (%s)",
3627 fl.smtp_exit_function_called = TRUE;
3629 /* Call the not-QUIT ACL, if there is one, unless no reason is given. */
3631 if (acl_smtp_notquit && reason)
3633 smtp_notquit_reason = reason;
3634 if ((rc = acl_check(ACL_WHERE_NOTQUIT, NULL, acl_smtp_notquit, &user_msg,
3635 &log_msg)) == ERROR)
3636 log_write(0, LOG_MAIN|LOG_PANIC, "ACL for not-QUIT returned ERROR: %s",
3640 /* If the connection was dropped, we certainly are no longer talking TLS */
3641 tls_in.active.sock = -1;
3643 /* Write an SMTP response if we are expected to give one. As the default
3644 responses are all internal, they should be reasonable size. */
3646 if (code && defaultrespond)
3649 smtp_respond(code, 3, TRUE, user_msg);
3655 va_start(ap, defaultrespond);
3656 g = string_vformat(NULL, SVFMT_EXTEND|SVFMT_REBUFFER, CS defaultrespond, ap);
3658 smtp_printf("%s %s\r\n", FALSE, code, string_from_gstring(g));
3667 /*************************************************
3668 * Verify HELO argument *
3669 *************************************************/
3671 /* This function is called if helo_verify_hosts or helo_try_verify_hosts is
3672 matched. It is also called from ACL processing if verify = helo is used and
3673 verification was not previously tried (i.e. helo_try_verify_hosts was not
3674 matched). The result of its processing is to set helo_verified and
3675 helo_verify_failed. These variables should both be FALSE for this function to
3678 Note that EHLO/HELO is legitimately allowed to quote an address literal. Allow
3679 for IPv6 ::ffff: literals.
3682 Returns: TRUE if testing was completed;
3683 FALSE on a temporary failure
3687 smtp_verify_helo(void)
3691 HDEBUG(D_receive) debug_printf("verifying EHLO/HELO argument \"%s\"\n",
3694 if (sender_helo_name == NULL)
3696 HDEBUG(D_receive) debug_printf("no EHLO/HELO command was issued\n");
3699 /* Deal with the case of -bs without an IP address */
3701 else if (sender_host_address == NULL)
3703 HDEBUG(D_receive) debug_printf("no client IP address: assume success\n");
3704 f.helo_verified = TRUE;
3707 /* Deal with the more common case when there is a sending IP address */
3709 else if (sender_helo_name[0] == '[')
3711 f.helo_verified = Ustrncmp(sender_helo_name+1, sender_host_address,
3712 Ustrlen(sender_host_address)) == 0;
3715 if (!f.helo_verified)
3717 if (strncmpic(sender_host_address, US"::ffff:", 7) == 0)
3718 f.helo_verified = Ustrncmp(sender_helo_name + 1,
3719 sender_host_address + 7, Ustrlen(sender_host_address) - 7) == 0;
3724 { if (f.helo_verified) debug_printf("matched host address\n"); }
3727 /* Do a reverse lookup if one hasn't already given a positive or negative
3728 response. If that fails, or the name doesn't match, try checking with a forward
3733 if (sender_host_name == NULL && !host_lookup_failed)
3734 yield = host_name_lookup() != DEFER;
3736 /* If a host name is known, check it and all its aliases. */
3738 if (sender_host_name)
3739 if ((f.helo_verified = strcmpic(sender_host_name, sender_helo_name) == 0))
3741 sender_helo_dnssec = sender_host_dnssec;
3742 HDEBUG(D_receive) debug_printf("matched host name\n");
3746 uschar **aliases = sender_host_aliases;
3748 if ((f.helo_verified = strcmpic(*aliases++, sender_helo_name) == 0))
3750 sender_helo_dnssec = sender_host_dnssec;
3754 HDEBUG(D_receive) if (f.helo_verified)
3755 debug_printf("matched alias %s\n", *(--aliases));
3758 /* Final attempt: try a forward lookup of the helo name */
3760 if (!f.helo_verified)
3764 {.name = sender_helo_name, .address = NULL, .mx = MX_NONE, .next = NULL};
3766 {.request = US"*", .require = US""};
3768 HDEBUG(D_receive) debug_printf("getting IP address for %s\n",
3770 rc = host_find_bydns(&h, NULL, HOST_FIND_BY_A | HOST_FIND_BY_AAAA,
3771 NULL, NULL, NULL, &d, NULL, NULL);
3772 if (rc == HOST_FOUND || rc == HOST_FOUND_LOCAL)
3773 for (host_item * hh = &h; hh; hh = hh->next)
3774 if (Ustrcmp(hh->address, sender_host_address) == 0)
3776 f.helo_verified = TRUE;
3777 if (h.dnssec == DS_YES) sender_helo_dnssec = TRUE;
3779 debug_printf("IP address for %s matches calling address\n"
3780 "Forward DNS security status: %sverified\n",
3781 sender_helo_name, sender_helo_dnssec ? "" : "un");
3787 if (!f.helo_verified) f.helo_verify_failed = TRUE; /* We've tried ... */
3794 /*************************************************
3795 * Send user response message *
3796 *************************************************/
3798 /* This function is passed a default response code and a user message. It calls
3799 smtp_message_code() to check and possibly modify the response code, and then
3800 calls smtp_respond() to transmit the response. I put this into a function
3801 just to avoid a lot of repetition.
3804 code the response code
3805 user_msg the user message
3811 smtp_user_msg(uschar *code, uschar *user_msg)
3814 smtp_message_code(&code, &len, &user_msg, NULL, TRUE);
3815 smtp_respond(code, len, TRUE, user_msg);
3821 smtp_in_auth(auth_instance *au, uschar ** smtp_resp, uschar ** errmsg)
3823 const uschar *set_id = NULL;
3826 /* Set up globals for error messages */
3828 authenticator_name = au->name;
3829 driver_srcfile = au->srcfile;
3830 driver_srcline = au->srcline;
3832 /* Run the checking code, passing the remainder of the command line as
3833 data. Initials the $auth<n> variables as empty. Initialize $0 empty and set
3834 it as the only set numerical variable. The authenticator may set $auth<n>
3835 and also set other numeric variables. The $auth<n> variables are preferred
3836 nowadays; the numerical variables remain for backwards compatibility.
3838 Afterwards, have a go at expanding the set_id string, even if
3839 authentication failed - for bad passwords it can be useful to log the
3840 userid. On success, require set_id to expand and exist, and put it in
3841 authenticated_id. Save this in permanent store, as the working store gets
3842 reset at HELO, RSET, etc. */
3844 for (int i = 0; i < AUTH_VARS; i++) auth_vars[i] = NULL;
3846 expand_nlength[0] = 0; /* $0 contains nothing */
3848 rc = (au->info->servercode)(au, smtp_cmd_data);
3849 if (au->set_id) set_id = expand_string(au->set_id);
3850 expand_nmax = -1; /* Reset numeric variables */
3851 for (int i = 0; i < AUTH_VARS; i++) auth_vars[i] = NULL; /* Reset $auth<n> */
3852 driver_srcfile = authenticator_name = NULL; driver_srcline = 0;
3854 /* The value of authenticated_id is stored in the spool file and printed in
3855 log lines. It must not contain binary zeros or newline characters. In
3856 normal use, it never will, but when playing around or testing, this error
3857 can (did) happen. To guard against this, ensure that the id contains only
3858 printing characters. */
3860 if (set_id) set_id = string_printing(set_id);
3862 /* For the non-OK cases, set up additional logging data if set_id
3866 set_id = set_id && *set_id
3867 ? string_sprintf(" (set_id=%s)", set_id) : US"";
3869 /* Switch on the result */
3874 if (!au->set_id || set_id) /* Complete success */
3876 if (set_id) authenticated_id = string_copy_perm(set_id, TRUE);
3877 sender_host_authenticated = au->name;
3878 sender_host_auth_pubname = au->public_name;
3879 authentication_failed = FALSE;
3880 authenticated_fail_id = NULL; /* Impossible to already be set? */
3883 (sender_host_address ? protocols : protocols_local)
3884 [pextend + pauthed + (tls_in.active.sock >= 0 ? pcrpted:0)];
3885 *smtp_resp = *errmsg = US"235 Authentication succeeded";
3886 authenticated_by = au;
3890 /* Authentication succeeded, but we failed to expand the set_id string.
3891 Treat this as a temporary error. */
3893 auth_defer_msg = expand_string_message;
3897 if (set_id) authenticated_fail_id = string_copy_perm(set_id, TRUE);
3898 *smtp_resp = string_sprintf("435 Unable to authenticate at present%s",
3899 auth_defer_user_msg);
3900 *errmsg = string_sprintf("435 Unable to authenticate at present%s: %s",
3901 set_id, auth_defer_msg);
3905 *smtp_resp = *errmsg = US"501 Invalid base64 data";
3909 *smtp_resp = *errmsg = US"501 Authentication cancelled";
3913 *smtp_resp = *errmsg = US"553 Initial data not expected";
3917 if (set_id) authenticated_fail_id = string_copy_perm(set_id, TRUE);
3918 *smtp_resp = US"535 Incorrect authentication data";
3919 *errmsg = string_sprintf("535 Incorrect authentication data%s", set_id);
3923 if (set_id) authenticated_fail_id = string_copy_perm(set_id, TRUE);
3924 *smtp_resp = US"435 Internal error";
3925 *errmsg = string_sprintf("435 Internal error%s: return %d from authentication "
3926 "check", set_id, rc);
3938 qualify_recipient(uschar ** recipient, uschar * smtp_cmd_data, uschar * tag)
3941 if (f.allow_unqualified_recipient || strcmpic(*recipient, US"postmaster") == 0)
3943 DEBUG(D_receive) debug_printf("unqualified address %s accepted\n",
3945 rd = Ustrlen(recipient) + 1;
3946 /* deconst ok as *recipient was not const */
3947 *recipient = US rewrite_address_qualify(*recipient, TRUE);
3950 smtp_printf("501 %s: recipient address must contain a domain\r\n", FALSE,
3952 log_write(L_smtp_syntax_error,
3953 LOG_MAIN|LOG_REJECT, "unqualified %s rejected: <%s> %s%s",
3954 tag, *recipient, host_and_ident(TRUE), host_lookup_msg);
3962 smtp_quit_handler(uschar ** user_msgp, uschar ** log_msgp)
3965 f.smtp_in_quit = TRUE;
3966 incomplete_transaction_log(US"QUIT");
3968 && acl_check(ACL_WHERE_QUIT, NULL, acl_smtp_quit, user_msgp, log_msgp)
3970 log_write(0, LOG_MAIN|LOG_PANIC, "ACL for QUIT returned ERROR: %s",
3973 #ifdef EXIM_TCP_CORK
3974 (void) setsockopt(fileno(smtp_out), IPPROTO_TCP, EXIM_TCP_CORK, US &on, sizeof(on));
3978 smtp_respond(US"221", 3, TRUE, *user_msgp);
3980 smtp_printf("221 %s closing connection\r\n", FALSE, smtp_active_hostname);
3982 #ifdef SERVERSIDE_CLOSE_NOWAIT
3983 # ifndef DISABLE_TLS
3984 tls_close(NULL, TLS_SHUTDOWN_NOWAIT);
3987 log_write(L_smtp_connection, LOG_MAIN, "%s closed by QUIT",
3988 smtp_get_connection_info());
3991 # ifndef DISABLE_TLS
3992 tls_close(NULL, TLS_SHUTDOWN_WAIT);
3995 log_write(L_smtp_connection, LOG_MAIN, "%s closed by QUIT",
3996 smtp_get_connection_info());
3998 /* Pause, hoping client will FIN first so that they get the TIME_WAIT.
3999 The socket should become readble (though with no data) */
4001 (void) poll_one_fd(fileno(smtp_in), POLLIN, 200);
4002 #endif /*!SERVERSIDE_CLOSE_NOWAIT*/
4007 smtp_rset_handler(void)
4010 incomplete_transaction_log(US"RSET");
4011 smtp_printf("250 Reset OK\r\n", FALSE);
4012 cmd_list[CMD_LIST_RSET].is_mail_cmd = FALSE;
4013 if (chunking_state > CHUNKING_OFFERED)
4014 chunking_state = CHUNKING_OFFERED;
4019 expand_mailmax(const uschar * s)
4021 if (!(s = expand_cstring(s)))
4022 log_write(0, LOG_MAIN|LOG_PANIC, "failed to expand smtp_accept_max_per_connection");
4023 return *s ? Uatoi(s) : 0;
4026 /*************************************************
4027 * Initialize for SMTP incoming message *
4028 *************************************************/
4030 /* This function conducts the initial dialogue at the start of an incoming SMTP
4031 message, and builds a list of recipients. However, if the incoming message
4032 is part of a batch (-bS option) a separate function is called since it would
4033 be messy having tests splattered about all over this function. This function
4034 therefore handles the case where interaction is occurring. The input and output
4035 files are set up in smtp_in and smtp_out.
4037 The global recipients_list is set to point to a vector of recipient_item
4038 blocks, whose number is given by recipients_count. This is extended by the
4039 receive_add_recipient() function. The global variable sender_address is set to
4040 the sender's address. The yield is +1 if a message has been successfully
4041 started, 0 if a QUIT command was encountered or the connection was refused from
4042 the particular host, or -1 if the connection was lost.
4046 Returns: > 0 message successfully started (reached DATA)
4047 = 0 QUIT read or end of file reached or call refused
4052 smtp_setup_msg(void)
4055 BOOL toomany = FALSE;
4056 BOOL discarded = FALSE;
4057 BOOL last_was_rej_mail = FALSE;
4058 BOOL last_was_rcpt = FALSE;
4059 rmark reset_point = store_mark();
4061 DEBUG(D_receive) debug_printf("smtp_setup_msg entered\n");
4063 /* Reset for start of new message. We allow one RSET not to be counted as a
4064 nonmail command, for those MTAs that insist on sending it between every
4065 message. Ditto for EHLO/HELO and for STARTTLS, to allow for going in and out of
4066 TLS between messages (an Exim client may do this if it has messages queued up
4067 for the host). Note: we do NOT reset AUTH at this point. */
4069 reset_point = smtp_reset(reset_point);
4070 message_ended = END_NOTSTARTED;
4072 chunking_state = f.chunking_offered ? CHUNKING_OFFERED : CHUNKING_NOT_OFFERED;
4074 cmd_list[CMD_LIST_RSET].is_mail_cmd = TRUE;
4075 cmd_list[CMD_LIST_HELO].is_mail_cmd = TRUE;
4076 cmd_list[CMD_LIST_EHLO].is_mail_cmd = TRUE;
4078 cmd_list[CMD_LIST_STARTTLS].is_mail_cmd = TRUE;
4081 if (lwr_receive_getc != NULL)
4083 /* This should have already happened, but if we've gotten confused,
4084 force a reset here. */
4085 DEBUG(D_receive) debug_printf("WARNING: smtp_setup_msg had to restore receive functions to lowers\n");
4086 bdat_pop_receive_functions();
4089 /* Set the local signal handler for SIGTERM - it tries to end off tidily */
4091 had_command_sigterm = 0;
4092 os_non_restarting_signal(SIGTERM, command_sigterm_handler);
4094 /* Batched SMTP is handled in a different function. */
4096 if (smtp_batched_input) return smtp_setup_batch_msg();
4099 if (smtp_in) /* Avoid pure-ACKs while in cmd pingpong phase */
4100 (void) setsockopt(fileno(smtp_in), IPPROTO_TCP, TCP_QUICKACK,
4101 US &off, sizeof(off));
4104 /* Deal with SMTP commands. This loop is exited by setting done to a POSITIVE
4105 value. The values are 2 larger than the required yield of the function. */
4109 const uschar **argv;
4110 uschar *etrn_command;
4111 uschar *etrn_serialize_key;
4113 uschar *log_msg, *smtp_code;
4114 uschar *user_msg = NULL;
4115 uschar *recipient = NULL;
4116 uschar *hello = NULL;
4118 BOOL was_rej_mail = FALSE;
4119 BOOL was_rcpt = FALSE;
4120 void (*oldsignal)(int);
4122 int start, end, sender_domain, recipient_domain;
4125 uschar *orcpt = NULL;
4130 /* Check once per STARTTLS or SSL-on-connect for a TLS AUTH */
4131 if ( tls_in.active.sock >= 0
4133 && tls_in.certificate_verified
4134 && cmd_list[CMD_LIST_TLS_AUTH].is_mail_cmd
4137 cmd_list[CMD_LIST_TLS_AUTH].is_mail_cmd = FALSE;
4139 for (auth_instance * au = auths; au; au = au->next)
4140 if (strcmpic(US"tls", au->driver_name) == 0)
4143 && (rc = acl_check(ACL_WHERE_AUTH, NULL, acl_smtp_auth,
4144 &user_msg, &log_msg)) != OK
4146 done = smtp_handle_acl_fail(ACL_WHERE_AUTH, rc, user_msg, log_msg);
4149 smtp_cmd_data = NULL;
4151 if (smtp_in_auth(au, &s, &ss) == OK)
4152 { DEBUG(D_auth) debug_printf("tls auth succeeded\n"); }
4155 DEBUG(D_auth) debug_printf("tls auth not succeeded\n");
4156 #ifndef DISABLE_EVENT
4158 uschar * save_name = sender_host_authenticated, * logmsg;
4159 sender_host_authenticated = au->name;
4160 if ((logmsg = event_raise(event_action, US"auth:fail", s, NULL)))
4161 log_write(0, LOG_MAIN, "%s", logmsg);
4162 sender_host_authenticated = save_name;
4172 switch(smtp_read_command(
4173 #ifndef DISABLE_PIPE_CONNECT
4174 !fl.pipe_connect_acceptable,
4178 GETC_BUFFER_UNLIMITED))
4180 /* The AUTH command is not permitted to occur inside a transaction, and may
4181 occur successfully only once per connection. Actually, that isn't quite
4182 true. When TLS is started, all previous information about a connection must
4183 be discarded, so a new AUTH is permitted at that time.
4185 AUTH may only be used when it has been advertised. However, it seems that
4186 there are clients that send AUTH when it hasn't been advertised, some of
4187 them even doing this after HELO. And there are MTAs that accept this. Sigh.
4188 So there's a get-out that allows this to happen.
4190 AUTH is initially labelled as a "nonmail command" so that one occurrence
4191 doesn't get counted. We change the label here so that multiple failing
4192 AUTHS will eventually hit the nonmail threshold. */
4196 authentication_failed = TRUE;
4197 cmd_list[CMD_LIST_AUTH].is_mail_cmd = FALSE;
4199 if (!fl.auth_advertised && !f.allow_auth_unadvertised)
4201 done = synprot_error(L_smtp_protocol_error, 503, NULL,
4202 US"AUTH command used when not advertised");
4205 if (sender_host_authenticated)
4207 done = synprot_error(L_smtp_protocol_error, 503, NULL,
4208 US"already authenticated");
4213 done = synprot_error(L_smtp_protocol_error, 503, NULL,
4214 US"not permitted in mail transaction");
4221 && (rc = acl_check(ACL_WHERE_AUTH, NULL, acl_smtp_auth,
4222 &user_msg, &log_msg)) != OK
4225 done = smtp_handle_acl_fail(ACL_WHERE_AUTH, rc, user_msg, log_msg);
4229 /* Find the name of the requested authentication mechanism. */
4232 for (; (c = *smtp_cmd_data) && !isspace(c); smtp_cmd_data++)
4233 if (!isalnum(c) && c != '-' && c != '_')
4235 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4236 US"invalid character in authentication mechanism name");
4240 /* If not at the end of the line, we must be at white space. Terminate the
4241 name and move the pointer on to any data that may be present. */
4245 *smtp_cmd_data++ = 0;
4246 while (isspace(*smtp_cmd_data)) smtp_cmd_data++;
4249 /* Search for an authentication mechanism which is configured for use
4250 as a server and which has been advertised (unless, sigh, allow_auth_
4251 unadvertised is set). */
4255 uschar * smtp_resp, * errmsg;
4257 for (au = auths; au; au = au->next)
4258 if (strcmpic(s, au->public_name) == 0 && au->server &&
4259 (au->advertised || f.allow_auth_unadvertised))
4264 int rc = smtp_in_auth(au, &smtp_resp, &errmsg);
4266 smtp_printf("%s\r\n", FALSE, smtp_resp);
4269 uschar * logmsg = NULL;
4270 #ifndef DISABLE_EVENT
4271 {uschar * save_name = sender_host_authenticated;
4272 sender_host_authenticated = au->name;
4273 logmsg = event_raise(event_action, US"auth:fail", smtp_resp, NULL);
4274 sender_host_authenticated = save_name;
4278 log_write(0, LOG_MAIN|LOG_REJECT, "%s", logmsg);
4280 log_write(0, LOG_MAIN|LOG_REJECT, "%s authenticator failed for %s: %s",
4281 au->name, host_and_ident(FALSE), errmsg);
4285 done = synprot_error(L_smtp_protocol_error, 504, NULL,
4286 string_sprintf("%s authentication mechanism not supported", s));
4289 break; /* AUTH_CMD */
4291 /* The HELO/EHLO commands are permitted to appear in the middle of a
4292 session as well as at the beginning. They have the effect of a reset in
4293 addition to their other functions. Their absence at the start cannot be
4294 taken to be an error.
4298 If the EHLO command is not acceptable to the SMTP server, 501, 500,
4299 or 502 failure replies MUST be returned as appropriate. The SMTP
4300 server MUST stay in the same state after transmitting these replies
4301 that it was in before the EHLO was received.
4303 Therefore, we do not do the reset until after checking the command for
4304 acceptability. This change was made for Exim release 4.11. Previously
4305 it did the reset first. */
4318 HELO_EHLO: /* Common code for HELO and EHLO */
4319 cmd_list[CMD_LIST_HELO].is_mail_cmd = FALSE;
4320 cmd_list[CMD_LIST_EHLO].is_mail_cmd = FALSE;
4322 /* Reject the HELO if its argument was invalid or non-existent. A
4323 successful check causes the argument to be saved in malloc store. */
4325 if (!check_helo(smtp_cmd_data))
4327 smtp_printf("501 Syntactically invalid %s argument(s)\r\n", FALSE, hello);
4329 log_write(0, LOG_MAIN|LOG_REJECT, "rejected %s from %s: syntactically "
4330 "invalid argument(s): %s", hello, host_and_ident(FALSE),
4331 *smtp_cmd_argument == 0 ? US"(no argument given)" :
4332 string_printing(smtp_cmd_argument));
4334 if (++synprot_error_count > smtp_max_synprot_errors)
4336 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
4337 "syntax or protocol errors (last command was \"%s\", %s)",
4338 host_and_ident(FALSE), string_printing(smtp_cmd_buffer),
4339 string_from_gstring(s_connhad_log(NULL))
4347 /* If sender_host_unknown is true, we have got here via the -bs interface,
4348 not called from inetd. Otherwise, we are running an IP connection and the
4349 host address will be set. If the helo name is the primary name of this
4350 host and we haven't done a reverse lookup, force one now. If helo_verify_required
4351 is set, ensure that the HELO name matches the actual host. If helo_verify
4352 is set, do the same check, but softly. */
4354 if (!f.sender_host_unknown)
4356 BOOL old_helo_verified = f.helo_verified;
4357 uschar *p = smtp_cmd_data;
4359 while (*p != 0 && !isspace(*p)) { *p = tolower(*p); p++; }
4362 /* Force a reverse lookup if HELO quoted something in helo_lookup_domains
4363 because otherwise the log can be confusing. */
4365 if ( !sender_host_name
4366 && match_isinlist(sender_helo_name, CUSS &helo_lookup_domains, 0,
4367 &domainlist_anchor, NULL, MCL_DOMAIN, TRUE, NULL) == OK)
4368 (void)host_name_lookup();
4370 /* Rebuild the fullhost info to include the HELO name (and the real name
4371 if it was looked up.) */
4373 host_build_sender_fullhost(); /* Rebuild */
4374 set_process_info("handling%s incoming connection from %s",
4375 tls_in.active.sock >= 0 ? " TLS" : "", host_and_ident(FALSE));
4377 /* Verify if configured. This doesn't give much security, but it does
4378 make some people happy to be able to do it. If helo_verify_required is set,
4379 (host matches helo_verify_hosts) failure forces rejection. If helo_verify
4380 is set (host matches helo_try_verify_hosts), it does not. This is perhaps
4381 now obsolescent, since the verification can now be requested selectively
4384 f.helo_verified = f.helo_verify_failed = sender_helo_dnssec = FALSE;
4385 if (fl.helo_verify_required || fl.helo_verify)
4387 BOOL tempfail = !smtp_verify_helo();
4388 if (!f.helo_verified)
4390 if (fl.helo_verify_required)
4392 smtp_printf("%d %s argument does not match calling host\r\n", FALSE,
4393 tempfail? 451 : 550, hello);
4394 log_write(0, LOG_MAIN|LOG_REJECT, "%srejected \"%s %s\" from %s",
4395 tempfail? "temporarily " : "",
4396 hello, sender_helo_name, host_and_ident(FALSE));
4397 f.helo_verified = old_helo_verified;
4398 break; /* End of HELO/EHLO processing */
4400 HDEBUG(D_all) debug_printf("%s verification failed but host is in "
4401 "helo_try_verify_hosts\n", hello);
4407 /* set up SPF context */
4408 spf_conn_init(sender_helo_name, sender_host_address);
4411 /* Apply an ACL check if one is defined; afterwards, recheck
4412 synchronization in case the client started sending in a delay. */
4415 if ((rc = acl_check(ACL_WHERE_HELO, NULL, acl_smtp_helo,
4416 &user_msg, &log_msg)) != OK)
4418 done = smtp_handle_acl_fail(ACL_WHERE_HELO, rc, user_msg, log_msg);
4419 sender_helo_name = NULL;
4420 host_build_sender_fullhost(); /* Rebuild */
4423 #ifndef DISABLE_PIPE_CONNECT
4424 else if (!fl.pipe_connect_acceptable && !check_sync())
4426 else if (!check_sync())
4430 /* Generate an OK reply. The default string includes the ident if present,
4431 and also the IP address if present. Reflecting back the ident is intended
4432 as a deterrent to mail forgers. For maximum efficiency, and also because
4433 some broken systems expect each response to be in a single packet, arrange
4434 that the entire reply is sent in one write(). */
4436 fl.auth_advertised = FALSE;
4437 f.smtp_in_pipelining_advertised = FALSE;
4439 fl.tls_advertised = FALSE;
4441 fl.dsn_advertised = FALSE;
4443 fl.smtputf8_advertised = FALSE;
4446 /* Expand the per-connection message count limit option */
4447 smtp_mailcmd_max = expand_mailmax(smtp_accept_max_per_connection);
4449 smtp_code = US"250 "; /* Default response code plus space*/
4452 /* sender_host_name below will be tainted, so save on copy when we hit it */
4453 g = string_get_tainted(24, GET_TAINTED);
4454 g = string_fmt_append(g, "%.3s %s Hello %s%s%s",
4456 smtp_active_hostname,
4457 sender_ident ? sender_ident : US"",
4458 sender_ident ? US" at " : US"",
4459 sender_host_name ? sender_host_name : sender_helo_name);
4461 if (sender_host_address)
4462 g = string_fmt_append(g, " [%s]", sender_host_address);
4465 /* A user-supplied EHLO greeting may not contain more than one line. Note
4466 that the code returned by smtp_message_code() includes the terminating
4467 whitespace character. */
4473 smtp_message_code(&smtp_code, &codelen, &user_msg, NULL, TRUE);
4474 s = string_sprintf("%.*s%s", codelen, smtp_code, user_msg);
4475 if ((ss = strpbrk(CS s, "\r\n")) != NULL)
4477 log_write(0, LOG_MAIN|LOG_PANIC, "EHLO/HELO response must not contain "
4478 "newlines: message truncated: %s", string_printing(s));
4481 g = string_cat(NULL, s);
4484 g = string_catn(g, US"\r\n", 2);
4486 /* If we received EHLO, we must create a multiline response which includes
4487 the functions supported. */
4493 /* I'm not entirely happy with this, as an MTA is supposed to check
4494 that it has enough room to accept a message of maximum size before
4495 it sends this. However, there seems little point in not sending it.
4496 The actual size check happens later at MAIL FROM time. By postponing it
4497 till then, VRFY and EXPN can be used after EHLO when space is short. */
4499 if (thismessage_size_limit > 0)
4500 g = string_fmt_append(g, "%.3s-SIZE %d\r\n", smtp_code,
4501 thismessage_size_limit);
4504 g = string_catn(g, smtp_code, 3);
4505 g = string_catn(g, US"-SIZE\r\n", 7);
4508 #ifdef EXPERIMENTAL_ESMTP_LIMITS
4509 if ( (smtp_mailcmd_max > 0 || recipients_max)
4510 && verify_check_host(&limits_advertise_hosts) == OK)
4512 g = string_fmt_append(g, "%.3s-LIMITS", smtp_code);
4513 if (smtp_mailcmd_max > 0)
4514 g = string_fmt_append(g, " MAILMAX=%d", smtp_mailcmd_max);
4516 g = string_fmt_append(g, " RCPTMAX=%d", recipients_max);
4517 g = string_catn(g, US"\r\n", 2);
4521 /* Exim does not do protocol conversion or data conversion. It is 8-bit
4522 clean; if it has an 8-bit character in its hand, it just sends it. It
4523 cannot therefore specify 8BITMIME and remain consistent with the RFCs.
4524 However, some users want this option simply in order to stop MUAs
4525 mangling messages that contain top-bit-set characters. It is therefore
4526 provided as an option. */
4528 if (accept_8bitmime)
4530 g = string_catn(g, smtp_code, 3);
4531 g = string_catn(g, US"-8BITMIME\r\n", 11);
4534 /* Advertise DSN support if configured to do so. */
4535 if (verify_check_host(&dsn_advertise_hosts) != FAIL)
4537 g = string_catn(g, smtp_code, 3);
4538 g = string_catn(g, US"-DSN\r\n", 6);
4539 fl.dsn_advertised = TRUE;
4542 /* Advertise ETRN/VRFY/EXPN if there's are ACL checking whether a host is
4543 permitted to issue them; a check is made when any host actually tries. */
4547 g = string_catn(g, smtp_code, 3);
4548 g = string_catn(g, US"-ETRN\r\n", 7);
4552 g = string_catn(g, smtp_code, 3);
4553 g = string_catn(g, US"-VRFY\r\n", 7);
4557 g = string_catn(g, smtp_code, 3);
4558 g = string_catn(g, US"-EXPN\r\n", 7);
4561 /* Exim is quite happy with pipelining, so let the other end know that
4562 it is safe to use it, unless advertising is disabled. */
4564 if ( f.pipelining_enable
4565 && verify_check_host(&pipelining_advertise_hosts) == OK)
4567 g = string_catn(g, smtp_code, 3);
4568 g = string_catn(g, US"-PIPELINING\r\n", 13);
4569 sync_cmd_limit = NON_SYNC_CMD_PIPELINING;
4570 f.smtp_in_pipelining_advertised = TRUE;
4572 #ifndef DISABLE_PIPE_CONNECT
4573 if (fl.pipe_connect_acceptable)
4575 f.smtp_in_early_pipe_advertised = TRUE;
4576 g = string_catn(g, smtp_code, 3);
4577 g = string_catn(g, US"-" EARLY_PIPE_FEATURE_NAME "\r\n", EARLY_PIPE_FEATURE_LEN+3);
4583 /* If any server authentication mechanisms are configured, advertise
4584 them if the current host is in auth_advertise_hosts. The problem with
4585 advertising always is that some clients then require users to
4586 authenticate (and aren't configurable otherwise) even though it may not
4587 be necessary (e.g. if the host is in host_accept_relay).
4589 RFC 2222 states that SASL mechanism names contain only upper case
4590 letters, so output the names in upper case, though we actually recognize
4591 them in either case in the AUTH command. */
4595 && !sender_host_authenticated
4597 && verify_check_host(&auth_advertise_hosts) == OK
4601 for (auth_instance * au = auths; au; au = au->next)
4603 au->advertised = FALSE;
4606 DEBUG(D_auth+D_expand) debug_printf_indent(
4607 "Evaluating advertise_condition for %s %s athenticator\n",
4608 au->name, au->public_name);
4609 if ( !au->advertise_condition
4610 || expand_check_condition(au->advertise_condition, au->name,
4617 g = string_catn(g, smtp_code, 3);
4618 g = string_catn(g, US"-AUTH", 5);
4620 fl.auth_advertised = TRUE;
4623 g = string_catn(g, US" ", 1);
4624 g = string_cat (g, au->public_name);
4625 while (++saveptr < g->ptr) g->s[saveptr] = toupper(g->s[saveptr]);
4626 au->advertised = TRUE;
4631 if (!first) g = string_catn(g, US"\r\n", 2);
4634 /* RFC 3030 CHUNKING */
4636 if (verify_check_host(&chunking_advertise_hosts) != FAIL)
4638 g = string_catn(g, smtp_code, 3);
4639 g = string_catn(g, US"-CHUNKING\r\n", 11);
4640 f.chunking_offered = TRUE;
4641 chunking_state = CHUNKING_OFFERED;
4644 /* Advertise TLS (Transport Level Security) aka SSL (Secure Socket Layer)
4645 if it has been included in the binary, and the host matches
4646 tls_advertise_hosts. We must *not* advertise if we are already in a
4647 secure connection. */
4650 if (tls_in.active.sock < 0 &&
4651 verify_check_host(&tls_advertise_hosts) != FAIL)
4653 g = string_catn(g, smtp_code, 3);
4654 g = string_catn(g, US"-STARTTLS\r\n", 11);
4655 fl.tls_advertised = TRUE;
4659 #ifndef DISABLE_PRDR
4660 /* Per Recipient Data Response, draft by Eric A. Hall extending RFC */
4663 g = string_catn(g, smtp_code, 3);
4664 g = string_catn(g, US"-PRDR\r\n", 7);
4669 if ( accept_8bitmime
4670 && verify_check_host(&smtputf8_advertise_hosts) != FAIL)
4672 g = string_catn(g, smtp_code, 3);
4673 g = string_catn(g, US"-SMTPUTF8\r\n", 11);
4674 fl.smtputf8_advertised = TRUE;
4678 /* Finish off the multiline reply with one that is always available. */
4680 g = string_catn(g, smtp_code, 3);
4681 g = string_catn(g, US" HELP\r\n", 7);
4684 /* Terminate the string (for debug), write it, and note that HELO/EHLO
4688 if (tls_in.active.sock >= 0)
4689 (void)tls_write(NULL, g->s, g->ptr,
4690 # ifndef DISABLE_PIPE_CONNECT
4691 fl.pipe_connect_acceptable && pipeline_connect_sends());
4697 (void) fwrite(g->s, 1, g->ptr, smtp_out);
4699 DEBUG(D_receive) for (const uschar * t, * s = string_from_gstring(g);
4700 s && (t = Ustrchr(s, '\r'));
4701 s = t + 2) /* \r\n */
4702 debug_printf("%s %.*s\n",
4703 s == g->s ? "SMTP>>" : " ",
4705 fl.helo_seen = TRUE;
4707 /* Reset the protocol and the state, abandoning any previous message. */
4709 (sender_host_address ? protocols : protocols_local)
4711 ? pextend + (sender_host_authenticated ? pauthed : 0)
4713 + (tls_in.active.sock >= 0 ? pcrpted : 0)
4715 cancel_cutthrough_connection(TRUE, US"sent EHLO response");
4716 reset_point = smtp_reset(reset_point);
4718 break; /* HELO/EHLO */
4721 /* The MAIL command requires an address as an operand. All we do
4722 here is to parse it for syntactic correctness. The form "<>" is
4723 a special case which converts into an empty string. The start/end
4724 pointers in the original are not used further for this address, as
4725 it is the canonical extracted address which is all that is kept. */
4729 smtp_mailcmd_count++; /* Count for limit and ratelimit */
4731 was_rej_mail = TRUE; /* Reset if accepted */
4732 env_mail_type_t * mail_args; /* Sanity check & validate args */
4735 if ( fl.helo_verify_required
4736 || verify_check_host(&hosts_require_helo) == OK)
4738 smtp_printf("503 HELO or EHLO required\r\n", FALSE);
4739 log_write(0, LOG_MAIN|LOG_REJECT, "rejected MAIL from %s: no "
4740 "HELO/EHLO given", host_and_ident(FALSE));
4743 else if (smtp_mailcmd_max < 0)
4744 smtp_mailcmd_max = expand_mailmax(smtp_accept_max_per_connection);
4748 done = synprot_error(L_smtp_protocol_error, 503, NULL,
4749 US"sender already given");
4753 if (!*smtp_cmd_data)
4755 done = synprot_error(L_smtp_protocol_error, 501, NULL,
4756 US"MAIL must have an address operand");
4760 /* Check to see if the limit for messages per connection would be
4761 exceeded by accepting further messages. */
4763 if (smtp_mailcmd_max > 0 && smtp_mailcmd_count > smtp_mailcmd_max)
4765 smtp_printf("421 too many messages in this connection\r\n", FALSE);
4766 log_write(0, LOG_MAIN|LOG_REJECT, "rejected MAIL command %s: too many "
4767 "messages in one connection", host_and_ident(TRUE));
4771 /* Reset for start of message - even if this is going to fail, we
4772 obviously need to throw away any previous data. */
4774 cancel_cutthrough_connection(TRUE, US"MAIL received");
4775 reset_point = smtp_reset(reset_point);
4777 sender_data = recipient_data = NULL;
4779 /* Loop, checking for ESMTP additions to the MAIL FROM command. */
4781 if (fl.esmtp) for(;;)
4783 uschar *name, *value, *end;
4784 unsigned long int size;
4785 BOOL arg_error = FALSE;
4787 if (!extract_option(&name, &value)) break;
4789 for (mail_args = env_mail_type_list;
4790 mail_args->value != ENV_MAIL_OPT_NULL;
4793 if (strcmpic(name, mail_args->name) == 0)
4795 if (mail_args->need_value && strcmpic(value, US"") == 0)
4798 switch(mail_args->value)
4800 /* Handle SIZE= by reading the value. We don't do the check till later,
4801 in order to be able to log the sender address on failure. */
4802 case ENV_MAIL_OPT_SIZE:
4803 if (((size = Ustrtoul(value, &end, 10)), *end == 0))
4805 if ((size == ULONG_MAX && errno == ERANGE) || size > INT_MAX)
4807 message_size = (int)size;
4813 /* If this session was initiated with EHLO and accept_8bitmime is set,
4814 Exim will have indicated that it supports the BODY=8BITMIME option. In
4815 fact, it does not support this according to the RFCs, in that it does not
4816 take any special action for forwarding messages containing 8-bit
4817 characters. That is why accept_8bitmime is not the default setting, but
4818 some sites want the action that is provided. We recognize both "8BITMIME"
4819 and "7BIT" as body types, but take no action. */
4820 case ENV_MAIL_OPT_BODY:
4821 if (accept_8bitmime) {
4822 if (strcmpic(value, US"8BITMIME") == 0)
4824 else if (strcmpic(value, US"7BIT") == 0)
4829 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4830 US"invalid data for BODY");
4833 DEBUG(D_receive) debug_printf("8BITMIME: %d\n", body_8bitmime);
4839 /* Handle the two DSN options, but only if configured to do so (which
4840 will have caused "DSN" to be given in the EHLO response). The code itself
4841 is included only if configured in at build time. */
4843 case ENV_MAIL_OPT_RET:
4844 if (fl.dsn_advertised)
4846 /* Check if RET has already been set */
4849 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4850 US"RET can be specified once only");
4853 dsn_ret = strcmpic(value, US"HDRS") == 0
4855 : strcmpic(value, US"FULL") == 0
4858 DEBUG(D_receive) debug_printf("DSN_RET: %d\n", dsn_ret);
4859 /* Check for invalid invalid value, and exit with error */
4862 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4863 US"Value for RET is invalid");
4868 case ENV_MAIL_OPT_ENVID:
4869 if (fl.dsn_advertised)
4871 /* Check if the dsn envid has been already set */
4874 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4875 US"ENVID can be specified once only");
4878 dsn_envid = string_copy(value);
4879 DEBUG(D_receive) debug_printf("DSN_ENVID: %s\n", dsn_envid);
4883 /* Handle the AUTH extension. If the value given is not "<>" and either
4884 the ACL says "yes" or there is no ACL but the sending host is
4885 authenticated, we set it up as the authenticated sender. However, if the
4886 authenticator set a condition to be tested, we ignore AUTH on MAIL unless
4887 the condition is met. The value of AUTH is an xtext, which means that +,
4888 = and cntrl chars are coded in hex; however "<>" is unaffected by this
4890 case ENV_MAIL_OPT_AUTH:
4891 if (Ustrcmp(value, "<>") != 0)
4896 if (auth_xtextdecode(value, &authenticated_sender) < 0)
4898 /* Put back terminator overrides for error message */
4901 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4902 US"invalid data for AUTH");
4905 if (!acl_smtp_mailauth)
4907 ignore_msg = US"client not authenticated";
4908 rc = sender_host_authenticated ? OK : FAIL;
4912 ignore_msg = US"rejected by ACL";
4913 rc = acl_check(ACL_WHERE_MAILAUTH, NULL, acl_smtp_mailauth,
4914 &user_msg, &log_msg);
4920 if (authenticated_by == NULL ||
4921 authenticated_by->mail_auth_condition == NULL ||
4922 expand_check_condition(authenticated_by->mail_auth_condition,
4923 authenticated_by->name, US"authenticator"))
4924 break; /* Accept the AUTH */
4926 ignore_msg = US"server_mail_auth_condition failed";
4927 if (authenticated_id != NULL)
4928 ignore_msg = string_sprintf("%s: authenticated ID=\"%s\"",
4929 ignore_msg, authenticated_id);
4934 authenticated_sender = NULL;
4935 log_write(0, LOG_MAIN, "ignoring AUTH=%s from %s (%s)",
4936 value, host_and_ident(TRUE), ignore_msg);
4939 /* Should only get DEFER or ERROR here. Put back terminator
4940 overrides for error message */
4945 (void)smtp_handle_acl_fail(ACL_WHERE_MAILAUTH, rc, user_msg,
4952 #ifndef DISABLE_PRDR
4953 case ENV_MAIL_OPT_PRDR:
4955 prdr_requested = TRUE;
4960 case ENV_MAIL_OPT_UTF8:
4961 if (!fl.smtputf8_advertised)
4963 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4964 US"SMTPUTF8 used when not advertised");
4968 DEBUG(D_receive) debug_printf("smtputf8 requested\n");
4969 message_smtputf8 = allow_utf8_domains = TRUE;
4970 if (Ustrncmp(received_protocol, US"utf8", 4) != 0)
4972 int old_pool = store_pool;
4973 store_pool = POOL_PERM;
4974 received_protocol = string_sprintf("utf8%s", received_protocol);
4975 store_pool = old_pool;
4980 /* No valid option. Stick back the terminator characters and break
4981 the loop. Do the name-terminator second as extract_option sets
4982 value==name when it found no equal-sign.
4983 An error for a malformed address will occur. */
4984 case ENV_MAIL_OPT_NULL:
4992 /* Break out of for loop if switch() had bad argument or
4993 when start of the email address is reached */
4994 if (arg_error) break;
4997 /* If we have passed the threshold for rate limiting, apply the current
4998 delay, and update it for next time, provided this is a limited host. */
5000 if (smtp_mailcmd_count > smtp_rlm_threshold &&
5001 verify_check_host(&smtp_ratelimit_hosts) == OK)
5003 DEBUG(D_receive) debug_printf("rate limit MAIL: delay %.3g sec\n",
5004 smtp_delay_mail/1000.0);
5005 millisleep((int)smtp_delay_mail);
5006 smtp_delay_mail *= smtp_rlm_factor;
5007 if (smtp_delay_mail > (double)smtp_rlm_limit)
5008 smtp_delay_mail = (double)smtp_rlm_limit;
5011 /* Now extract the address, first applying any SMTP-time rewriting. The
5012 TRUE flag allows "<>" as a sender address. */
5014 raw_sender = rewrite_existflags & rewrite_smtp
5015 /* deconst ok as smtp_cmd_data was not const */
5016 ? US rewrite_one(smtp_cmd_data, rewrite_smtp, NULL, FALSE, US"",
5017 global_rewrite_rules)
5021 parse_extract_address(raw_sender, &errmess, &start, &end, &sender_domain,
5026 done = synprot_error(L_smtp_syntax_error, 501, smtp_cmd_data, errmess);
5030 sender_address = raw_sender;
5032 /* If there is a configured size limit for mail, check that this message
5033 doesn't exceed it. The check is postponed to this point so that the sender
5036 if (thismessage_size_limit > 0 && message_size > thismessage_size_limit)
5038 smtp_printf("552 Message size exceeds maximum permitted\r\n", FALSE);
5039 log_write(L_size_reject,
5040 LOG_MAIN|LOG_REJECT, "rejected MAIL FROM:<%s> %s: "
5041 "message too big: size%s=%d max=%d",
5043 host_and_ident(TRUE),
5044 (message_size == INT_MAX)? ">" : "",
5046 thismessage_size_limit);
5047 sender_address = NULL;
5051 /* Check there is enough space on the disk unless configured not to.
5052 When smtp_check_spool_space is set, the check is for thismessage_size_limit
5053 plus the current message - i.e. we accept the message only if it won't
5054 reduce the space below the threshold. Add 5000 to the size to allow for
5055 overheads such as the Received: line and storing of recipients, etc.
5056 By putting the check here, even when SIZE is not given, it allow VRFY
5057 and EXPN etc. to be used when space is short. */
5059 if (!receive_check_fs(
5060 smtp_check_spool_space && message_size >= 0
5061 ? message_size + 5000 : 0))
5063 smtp_printf("452 Space shortage, please try later\r\n", FALSE);
5064 sender_address = NULL;
5068 /* If sender_address is unqualified, reject it, unless this is a locally
5069 generated message, or the sending host or net is permitted to send
5070 unqualified addresses - typically local machines behaving as MUAs -
5071 in which case just qualify the address. The flag is set above at the start
5072 of the SMTP connection. */
5074 if (!sender_domain && *sender_address)
5075 if (f.allow_unqualified_sender)
5077 sender_domain = Ustrlen(sender_address) + 1;
5078 /* deconst ok as sender_address was not const */
5079 sender_address = US rewrite_address_qualify(sender_address, FALSE);
5080 DEBUG(D_receive) debug_printf("unqualified address %s accepted\n",
5085 smtp_printf("501 %s: sender address must contain a domain\r\n", FALSE,
5087 log_write(L_smtp_syntax_error,
5088 LOG_MAIN|LOG_REJECT,
5089 "unqualified sender rejected: <%s> %s%s",
5091 host_and_ident(TRUE),
5093 sender_address = NULL;
5097 /* Apply an ACL check if one is defined, before responding. Afterwards,
5098 when pipelining is not advertised, do another sync check in case the ACL
5099 delayed and the client started sending in the meantime. */
5103 rc = acl_check(ACL_WHERE_MAIL, NULL, acl_smtp_mail, &user_msg, &log_msg);
5104 if (rc == OK && !f.smtp_in_pipelining_advertised && !check_sync())
5110 if (rc == OK || rc == DISCARD)
5112 BOOL more = pipeline_response();
5115 smtp_printf("%s%s%s", more, US"250 OK",
5116 #ifndef DISABLE_PRDR
5117 prdr_requested ? US", PRDR Requested" : US"",
5124 #ifndef DISABLE_PRDR
5126 user_msg = string_sprintf("%s%s", user_msg, US", PRDR Requested");
5128 smtp_user_msg(US"250", user_msg);
5130 smtp_delay_rcpt = smtp_rlr_base;
5131 f.recipients_discarded = (rc == DISCARD);
5132 was_rej_mail = FALSE;
5136 done = smtp_handle_acl_fail(ACL_WHERE_MAIL, rc, user_msg, log_msg);
5137 sender_address = NULL;
5142 /* The RCPT command requires an address as an operand. There may be any
5143 number of RCPT commands, specifying multiple recipients. We build them all
5144 into a data structure. The start/end values given by parse_extract_address
5145 are not used, as we keep only the extracted address. */
5149 /* We got really to many recipients. A check against configured
5150 limits is done later */
5151 if (rcpt_count < 0 || rcpt_count >= INT_MAX/2)
5152 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "Too many recipients: %d", rcpt_count);
5154 was_rcpt = fl.rcpt_in_progress = TRUE;
5156 /* There must be a sender address; if the sender was rejected and
5157 pipelining was advertised, we assume the client was pipelining, and do not
5158 count this as a protocol error. Reset was_rej_mail so that further RCPTs
5159 get the same treatment. */
5161 if (!sender_address)
5163 if (f.smtp_in_pipelining_advertised && last_was_rej_mail)
5165 smtp_printf("503 sender not yet given\r\n", FALSE);
5166 was_rej_mail = TRUE;
5170 done = synprot_error(L_smtp_protocol_error, 503, NULL,
5171 US"sender not yet given");
5172 was_rcpt = FALSE; /* Not a valid RCPT */
5178 /* Check for an operand */
5180 if (!smtp_cmd_data[0])
5182 done = synprot_error(L_smtp_syntax_error, 501, NULL,
5183 US"RCPT must have an address operand");
5188 /* Set the DSN flags orcpt and dsn_flags from the session*/
5192 if (fl.esmtp) for(;;)
5194 uschar *name, *value;
5196 if (!extract_option(&name, &value))
5199 if (fl.dsn_advertised && strcmpic(name, US"ORCPT") == 0)
5201 /* Check whether orcpt has been already set */
5204 done = synprot_error(L_smtp_syntax_error, 501, NULL,
5205 US"ORCPT can be specified once only");
5208 orcpt = string_copy(value);
5209 DEBUG(D_receive) debug_printf("DSN orcpt: %s\n", orcpt);
5212 else if (fl.dsn_advertised && strcmpic(name, US"NOTIFY") == 0)
5214 /* Check if the notify flags have been already set */
5217 done = synprot_error(L_smtp_syntax_error, 501, NULL,
5218 US"NOTIFY can be specified once only");
5221 if (strcmpic(value, US"NEVER") == 0)
5222 dsn_flags |= rf_notify_never;
5229 while (*pp != 0 && *pp != ',') pp++;
5230 if (*pp == ',') *pp++ = 0;
5231 if (strcmpic(p, US"SUCCESS") == 0)
5233 DEBUG(D_receive) debug_printf("DSN: Setting notify success\n");
5234 dsn_flags |= rf_notify_success;
5236 else if (strcmpic(p, US"FAILURE") == 0)
5238 DEBUG(D_receive) debug_printf("DSN: Setting notify failure\n");
5239 dsn_flags |= rf_notify_failure;
5241 else if (strcmpic(p, US"DELAY") == 0)
5243 DEBUG(D_receive) debug_printf("DSN: Setting notify delay\n");
5244 dsn_flags |= rf_notify_delay;
5248 /* Catch any strange values */
5249 done = synprot_error(L_smtp_syntax_error, 501, NULL,
5250 US"Invalid value for NOTIFY parameter");
5255 DEBUG(D_receive) debug_printf("DSN Flags: %x\n", dsn_flags);
5259 /* Unknown option. Stick back the terminator characters and break
5260 the loop. An error for a malformed address will occur. */
5264 DEBUG(D_receive) debug_printf("Invalid RCPT option: %s : %s\n", name, value);
5271 /* Apply SMTP rewriting then extract the working address. Don't allow "<>"
5272 as a recipient address */
5274 recipient = rewrite_existflags & rewrite_smtp
5275 /* deconst ok as smtp_cmd_data was not const */
5276 ? US rewrite_one(smtp_cmd_data, rewrite_smtp, NULL, FALSE, US"",
5277 global_rewrite_rules)
5280 if (!(recipient = parse_extract_address(recipient, &errmess, &start, &end,
5281 &recipient_domain, FALSE)))
5283 done = synprot_error(L_smtp_syntax_error, 501, smtp_cmd_data, errmess);
5288 /* If the recipient address is unqualified, reject it, unless this is a
5289 locally generated message. However, unqualified addresses are permitted
5290 from a configured list of hosts and nets - typically when behaving as
5291 MUAs rather than MTAs. Sad that SMTP is used for both types of traffic,
5292 really. The flag is set at the start of the SMTP connection.
5294 RFC 1123 talks about supporting "the reserved mailbox postmaster"; I always
5295 assumed this meant "reserved local part", but the revision of RFC 821 and
5296 friends now makes it absolutely clear that it means *mailbox*. Consequently
5297 we must always qualify this address, regardless. */
5299 if (!recipient_domain)
5300 if (!(recipient_domain = qualify_recipient(&recipient, smtp_cmd_data,
5307 /* Check maximum allowed */
5309 if (rcpt_count+1 < 0 || rcpt_count > recipients_max && recipients_max > 0)
5311 if (recipients_max_reject)
5314 smtp_printf("552 too many recipients\r\n", FALSE);
5316 log_write(0, LOG_MAIN|LOG_REJECT, "too many recipients: message "
5317 "rejected: sender=<%s> %s", sender_address, host_and_ident(TRUE));
5322 smtp_printf("452 too many recipients\r\n", FALSE);
5324 log_write(0, LOG_MAIN|LOG_REJECT, "too many recipients: excess "
5325 "temporarily rejected: sender=<%s> %s", sender_address,
5326 host_and_ident(TRUE));
5333 /* If we have passed the threshold for rate limiting, apply the current
5334 delay, and update it for next time, provided this is a limited host. */
5336 if (rcpt_count > smtp_rlr_threshold &&
5337 verify_check_host(&smtp_ratelimit_hosts) == OK)
5339 DEBUG(D_receive) debug_printf("rate limit RCPT: delay %.3g sec\n",
5340 smtp_delay_rcpt/1000.0);
5341 millisleep((int)smtp_delay_rcpt);
5342 smtp_delay_rcpt *= smtp_rlr_factor;
5343 if (smtp_delay_rcpt > (double)smtp_rlr_limit)
5344 smtp_delay_rcpt = (double)smtp_rlr_limit;
5347 /* If the MAIL ACL discarded all the recipients, we bypass ACL checking
5348 for them. Otherwise, check the access control list for this recipient. As
5349 there may be a delay in this, re-check for a synchronization error
5350 afterwards, unless pipelining was advertised. */
5352 if (f.recipients_discarded)
5355 if ( (rc = acl_check(ACL_WHERE_RCPT, recipient, acl_smtp_rcpt, &user_msg,
5357 && !f.smtp_in_pipelining_advertised && !check_sync())
5360 /* The ACL was happy */
5364 BOOL more = pipeline_response();
5367 smtp_user_msg(US"250", user_msg);
5369 smtp_printf("250 Accepted\r\n", more);
5370 receive_add_recipient(recipient, -1);
5372 /* Set the dsn flags in the recipients_list */
5373 recipients_list[recipients_count-1].orcpt = orcpt;
5374 recipients_list[recipients_count-1].dsn_flags = dsn_flags;
5376 /* DEBUG(D_receive) debug_printf("DSN: orcpt: %s flags: %d\n",
5377 recipients_list[recipients_count-1].orcpt,
5378 recipients_list[recipients_count-1].dsn_flags); */
5381 /* The recipient was discarded */
5383 else if (rc == DISCARD)
5386 smtp_user_msg(US"250", user_msg);
5388 smtp_printf("250 Accepted\r\n", FALSE);
5391 log_write(0, LOG_MAIN|LOG_REJECT, "%s F=<%s> RCPT %s: "
5392 "discarded by %s ACL%s%s", host_and_ident(TRUE),
5393 sender_address_unrewritten ? sender_address_unrewritten : sender_address,
5394 smtp_cmd_argument, f.recipients_discarded ? "MAIL" : "RCPT",
5395 log_msg ? US": " : US"", log_msg ? log_msg : US"");
5398 /* Either the ACL failed the address, or it was deferred. */
5402 if (rc == FAIL) rcpt_fail_count++; else rcpt_defer_count++;
5403 done = smtp_handle_acl_fail(ACL_WHERE_RCPT, rc, user_msg, log_msg);
5408 /* The DATA command is legal only if it follows successful MAIL FROM
5409 and RCPT TO commands. However, if pipelining is advertised, a bad DATA is
5410 not counted as a protocol error if it follows RCPT (which must have been
5411 rejected if there are no recipients.) This function is complete when a
5412 valid DATA command is encountered.
5414 Note concerning the code used: RFC 2821 says this:
5416 - If there was no MAIL, or no RCPT, command, or all such commands
5417 were rejected, the server MAY return a "command out of sequence"
5418 (503) or "no valid recipients" (554) reply in response to the
5421 The example in the pipelining RFC 2920 uses 554, but I use 503 here
5422 because it is the same whether pipelining is in use or not.
5424 If all the RCPT commands that precede DATA provoked the same error message
5425 (often indicating some kind of system error), it is helpful to include it
5426 with the DATA rejection (an idea suggested by Tony Finch). */
5433 if (chunking_state != CHUNKING_OFFERED)
5435 done = synprot_error(L_smtp_protocol_error, 503, NULL,
5436 US"BDAT command used when CHUNKING not advertised");
5440 /* grab size, endmarker */
5442 if (sscanf(CS smtp_cmd_data, "%u %n", &chunking_datasize, &n) < 1)
5444 done = synprot_error(L_smtp_protocol_error, 501, NULL,
5445 US"missing size for BDAT command");
5448 chunking_state = strcmpic(smtp_cmd_data+n, US"LAST") == 0
5449 ? CHUNKING_LAST : CHUNKING_ACTIVE;
5450 chunking_data_left = chunking_datasize;
5451 DEBUG(D_receive) debug_printf("chunking state %d, %d bytes\n",
5452 (int)chunking_state, chunking_data_left);
5454 f.bdat_readers_wanted = TRUE; /* FIXME: redundant vs chunking_state? */
5463 f.bdat_readers_wanted = FALSE;
5465 DATA_BDAT: /* Common code for DATA and BDAT */
5466 #ifndef DISABLE_PIPE_CONNECT
5467 fl.pipe_connect_acceptable = FALSE;
5469 if (!discarded && recipients_count <= 0)
5471 if (fl.rcpt_smtp_response_same && rcpt_smtp_response)
5473 uschar *code = US"503";
5474 int len = Ustrlen(rcpt_smtp_response);
5475 smtp_respond(code, 3, FALSE, US"All RCPT commands were rejected with "
5477 /* Responses from smtp_printf() will have \r\n on the end */
5478 if (len > 2 && rcpt_smtp_response[len-2] == '\r')
5479 rcpt_smtp_response[len-2] = 0;
5480 smtp_respond(code, 3, FALSE, rcpt_smtp_response);
5482 if (f.smtp_in_pipelining_advertised && last_was_rcpt)
5483 smtp_printf("503 Valid RCPT command must precede %s\r\n", FALSE,
5484 smtp_names[smtp_connection_had[SMTP_HBUFF_PREV(smtp_ch_index)]]);
5486 done = synprot_error(L_smtp_protocol_error, 503, NULL,
5487 smtp_connection_had[SMTP_HBUFF_PREV(smtp_ch_index)] == SCH_DATA
5488 ? US"valid RCPT command must precede DATA"
5489 : US"valid RCPT command must precede BDAT");
5491 if (chunking_state > CHUNKING_OFFERED)
5493 bdat_push_receive_functions();
5499 if (toomany && recipients_max_reject)
5501 sender_address = NULL; /* This will allow a new MAIL without RSET */
5502 sender_address_unrewritten = NULL;
5503 smtp_printf("554 Too many recipients\r\n", FALSE);
5505 if (chunking_state > CHUNKING_OFFERED)
5507 bdat_push_receive_functions();
5513 if (chunking_state > CHUNKING_OFFERED)
5514 rc = OK; /* No predata ACL or go-ahead output for BDAT */
5517 /* If there is an ACL, re-check the synchronization afterwards, since the
5518 ACL may have delayed. To handle cutthrough delivery enforce a dummy call
5519 to get the DATA command sent. */
5521 if (!acl_smtp_predata && cutthrough.cctx.sock < 0)
5525 uschar * acl = acl_smtp_predata ? acl_smtp_predata : US"accept";
5526 f.enable_dollar_recipients = TRUE;
5527 rc = acl_check(ACL_WHERE_PREDATA, NULL, acl, &user_msg,
5529 f.enable_dollar_recipients = FALSE;
5530 if (rc == OK && !check_sync())
5534 { /* Either the ACL failed the address, or it was deferred. */
5535 done = smtp_handle_acl_fail(ACL_WHERE_PREDATA, rc, user_msg, log_msg);
5541 smtp_user_msg(US"354", user_msg);
5544 "354 Enter message, ending with \".\" on a line by itself\r\n", FALSE);
5547 if (f.bdat_readers_wanted)
5548 bdat_push_receive_functions();
5551 if (smtp_in) /* all ACKs needed to ramp window up for bulk data */
5552 (void) setsockopt(fileno(smtp_in), IPPROTO_TCP, TCP_QUICKACK,
5553 US &on, sizeof(on));
5556 message_ended = END_NOTENDED; /* Indicate in middle of data */
5567 if (!(address = parse_extract_address(smtp_cmd_data, &errmess,
5568 &start, &end, &recipient_domain, FALSE)))
5570 smtp_printf("501 %s\r\n", FALSE, errmess);
5574 if (!recipient_domain)
5575 if (!(recipient_domain = qualify_recipient(&address, smtp_cmd_data,
5579 if ((rc = acl_check(ACL_WHERE_VRFY, address, acl_smtp_vrfy,
5580 &user_msg, &log_msg)) != OK)
5581 done = smtp_handle_acl_fail(ACL_WHERE_VRFY, rc, user_msg, log_msg);
5585 address_item * addr = deliver_make_addr(address, FALSE);
5587 switch(verify_address(addr, NULL, vopt_is_recipient | vopt_qualify, -1,
5588 -1, -1, NULL, NULL, NULL))
5591 s = string_sprintf("250 <%s> is deliverable", address);
5595 s = (addr->user_message != NULL)?
5596 string_sprintf("451 <%s> %s", address, addr->user_message) :
5597 string_sprintf("451 Cannot resolve <%s> at this time", address);
5601 s = (addr->user_message != NULL)?
5602 string_sprintf("550 <%s> %s", address, addr->user_message) :
5603 string_sprintf("550 <%s> is not deliverable", address);
5604 log_write(0, LOG_MAIN, "VRFY failed for %s %s",
5605 smtp_cmd_argument, host_and_ident(TRUE));
5609 smtp_printf("%s\r\n", FALSE, s);
5617 rc = acl_check(ACL_WHERE_EXPN, NULL, acl_smtp_expn, &user_msg, &log_msg);
5619 done = smtp_handle_acl_fail(ACL_WHERE_EXPN, rc, user_msg, log_msg);
5622 BOOL save_log_testing_mode = f.log_testing_mode;
5623 f.address_test_mode = f.log_testing_mode = TRUE;
5624 (void) verify_address(deliver_make_addr(smtp_cmd_data, FALSE),
5625 smtp_out, vopt_is_recipient | vopt_qualify | vopt_expn, -1, -1, -1,
5627 f.address_test_mode = FALSE;
5628 f.log_testing_mode = save_log_testing_mode; /* true for -bh */
5637 if (!fl.tls_advertised)
5639 done = synprot_error(L_smtp_protocol_error, 503, NULL,
5640 US"STARTTLS command used when not advertised");
5644 /* Apply an ACL check if one is defined */
5646 if ( acl_smtp_starttls
5647 && (rc = acl_check(ACL_WHERE_STARTTLS, NULL, acl_smtp_starttls,
5648 &user_msg, &log_msg)) != OK
5651 done = smtp_handle_acl_fail(ACL_WHERE_STARTTLS, rc, user_msg, log_msg);
5655 /* RFC 2487 is not clear on when this command may be sent, though it
5656 does state that all information previously obtained from the client
5657 must be discarded if a TLS session is started. It seems reasonable to
5658 do an implied RSET when STARTTLS is received. */
5660 incomplete_transaction_log(US"STARTTLS");
5661 cancel_cutthrough_connection(TRUE, US"STARTTLS received");
5662 reset_point = smtp_reset(reset_point);
5664 cmd_list[CMD_LIST_STARTTLS].is_mail_cmd = FALSE;
5666 /* There's an attack where more data is read in past the STARTTLS command
5667 before TLS is negotiated, then assumed to be part of the secure session
5668 when used afterwards; we use segregated input buffers, so are not
5669 vulnerable, but we want to note when it happens and, for sheer paranoia,
5670 ensure that the buffer is "wiped".
5671 Pipelining sync checks will normally have protected us too, unless disabled
5672 by configuration. */
5677 debug_printf("Non-empty input buffer after STARTTLS; naive attack?\n");
5678 if (tls_in.active.sock < 0)
5679 smtp_inend = smtp_inptr = smtp_inbuffer;
5680 /* and if TLS is already active, tls_server_start() should fail */
5683 /* There is nothing we value in the input buffer and if TLS is successfully
5684 negotiated, we won't use this buffer again; if TLS fails, we'll just read
5685 fresh content into it. The buffer contains arbitrary content from an
5686 untrusted remote source; eg: NOOP <shellcode>\r\nSTARTTLS\r\n
5687 It seems safest to just wipe away the content rather than leave it as a
5688 target to jump to. */
5690 memset(smtp_inbuffer, 0, IN_BUFFER_SIZE);
5692 /* Attempt to start up a TLS session, and if successful, discard all
5693 knowledge that was obtained previously. At least, that's what the RFC says,
5694 and that's what happens by default. However, in order to work round YAEB,
5695 there is an option to remember the esmtp state. Sigh.
5697 We must allow for an extra EHLO command and an extra AUTH command after
5698 STARTTLS that don't add to the nonmail command count. */
5701 if ((rc = tls_server_start(&s)) == OK)
5703 if (!tls_remember_esmtp)
5704 fl.helo_seen = fl.esmtp = fl.auth_advertised = f.smtp_in_pipelining_advertised = FALSE;
5705 cmd_list[CMD_LIST_EHLO].is_mail_cmd = TRUE;
5706 cmd_list[CMD_LIST_AUTH].is_mail_cmd = TRUE;
5707 cmd_list[CMD_LIST_TLS_AUTH].is_mail_cmd = TRUE;
5708 if (sender_helo_name)
5710 sender_helo_name = NULL;
5711 host_build_sender_fullhost(); /* Rebuild */
5712 set_process_info("handling incoming TLS connection from %s",
5713 host_and_ident(FALSE));
5716 (sender_host_address ? protocols : protocols_local)
5718 ? pextend + (sender_host_authenticated ? pauthed : 0)
5720 + (tls_in.active.sock >= 0 ? pcrpted : 0)
5723 sender_host_auth_pubname = sender_host_authenticated = NULL;
5724 authenticated_id = NULL;
5725 sync_cmd_limit = NON_SYNC_CMD_NON_PIPELINING;
5726 DEBUG(D_tls) debug_printf("TLS active\n");
5727 break; /* Successful STARTTLS */
5730 (void) smtp_log_tls_fail(s);
5732 /* Some local configuration problem was discovered before actually trying
5733 to do a TLS handshake; give a temporary error. */
5737 smtp_printf("454 TLS currently unavailable\r\n", FALSE);
5741 /* Hard failure. Reject everything except QUIT or closed connection. One
5742 cause for failure is a nested STARTTLS, in which case tls_in.active remains
5743 set, but we must still reject all incoming commands. Another is a handshake
5744 failure - and there may some encrypted data still in the pipe to us, which we
5745 see as garbage commands. */
5747 DEBUG(D_tls) debug_printf("TLS failed to start\n");
5748 while (done <= 0) switch(smtp_read_command(FALSE, GETC_BUFFER_UNLIMITED))
5751 log_write(L_smtp_connection, LOG_MAIN, "%s closed by EOF",
5752 smtp_get_connection_info());
5753 smtp_notquit_exit(US"tls-failed", NULL, NULL);
5757 /* It is perhaps arguable as to which exit ACL should be called here,
5758 but as it is probably a situation that almost never arises, it
5759 probably doesn't matter. We choose to call the real QUIT ACL, which in
5760 some sense is perhaps "right". */
5763 f.smtp_in_quit = TRUE;
5766 && ((rc = acl_check(ACL_WHERE_QUIT, NULL, acl_smtp_quit, &user_msg,
5767 &log_msg)) == ERROR))
5768 log_write(0, LOG_MAIN|LOG_PANIC, "ACL for QUIT returned ERROR: %s",
5771 smtp_respond(US"221", 3, TRUE, user_msg);
5773 smtp_printf("221 %s closing connection\r\n", FALSE, smtp_active_hostname);
5774 log_write(L_smtp_connection, LOG_MAIN, "%s closed by QUIT",
5775 smtp_get_connection_info());
5780 smtp_printf("554 Security failure\r\n", FALSE);
5783 tls_close(NULL, TLS_SHUTDOWN_NOWAIT);
5788 /* The ACL for QUIT is provided for gathering statistical information or
5789 similar; it does not affect the response code, but it can supply a custom
5793 smtp_quit_handler(&user_msg, &log_msg);
5799 smtp_rset_handler();
5800 cancel_cutthrough_connection(TRUE, US"RSET received");
5801 reset_point = smtp_reset(reset_point);
5808 smtp_printf("250 OK\r\n", FALSE);
5812 /* Show ETRN/EXPN/VRFY if there's an ACL for checking hosts; if actually
5813 used, a check will be done for permitted hosts. Show STARTTLS only if not
5814 already in a TLS session and if it would be advertised in the EHLO
5819 smtp_printf("214-Commands supported:\r\n", TRUE);
5823 Ustrcat(buffer, US" AUTH");
5825 if (tls_in.active.sock < 0 &&
5826 verify_check_host(&tls_advertise_hosts) != FAIL)
5827 Ustrcat(buffer, US" STARTTLS");
5829 Ustrcat(buffer, US" HELO EHLO MAIL RCPT DATA BDAT");
5830 Ustrcat(buffer, US" NOOP QUIT RSET HELP");
5831 if (acl_smtp_etrn) Ustrcat(buffer, US" ETRN");
5832 if (acl_smtp_expn) Ustrcat(buffer, US" EXPN");
5833 if (acl_smtp_vrfy) Ustrcat(buffer, US" VRFY");
5834 smtp_printf("214%s\r\n", FALSE, buffer);
5840 incomplete_transaction_log(US"connection lost");
5841 smtp_notquit_exit(US"connection-lost", US"421",
5842 US"%s lost input connection", smtp_active_hostname);
5844 /* Don't log by default unless in the middle of a message, as some mailers
5845 just drop the call rather than sending QUIT, and it clutters up the logs.
5848 if (sender_address || recipients_count > 0)
5849 log_write(L_lost_incoming_connection, LOG_MAIN,
5850 "unexpected %s while reading SMTP command from %s%s%s D=%s",
5851 f.sender_host_unknown ? "EOF" : "disconnection",
5852 f.tcp_in_fastopen_logged
5855 ? f.tcp_in_fastopen_data ? US"TFO* " : US"TFO "
5857 host_and_ident(FALSE), smtp_read_error,
5858 string_timesince(&smtp_connection_start)
5862 log_write(L_smtp_connection, LOG_MAIN, "%s %slost%s D=%s",
5863 smtp_get_connection_info(),
5864 f.tcp_in_fastopen && !f.tcp_in_fastopen_logged ? US"TFO " : US"",
5866 string_timesince(&smtp_connection_start)
5877 done = synprot_error(L_smtp_protocol_error, 503, NULL,
5878 US"ETRN is not permitted inside a transaction");
5882 log_write(L_etrn, LOG_MAIN, "ETRN %s received from %s", smtp_cmd_argument,
5883 host_and_ident(FALSE));
5885 if ((rc = acl_check(ACL_WHERE_ETRN, NULL, acl_smtp_etrn,
5886 &user_msg, &log_msg)) != OK)
5888 done = smtp_handle_acl_fail(ACL_WHERE_ETRN, rc, user_msg, log_msg);
5892 /* Compute the serialization key for this command. */
5894 etrn_serialize_key = string_sprintf("etrn-%s\n", smtp_cmd_data);
5896 /* If a command has been specified for running as a result of ETRN, we
5897 permit any argument to ETRN. If not, only the # standard form is permitted,
5898 since that is strictly the only kind of ETRN that can be implemented
5899 according to the RFC. */
5901 if (smtp_etrn_command)
5905 etrn_command = smtp_etrn_command;
5906 deliver_domain = smtp_cmd_data;
5907 rc = transport_set_up_command(&argv, smtp_etrn_command, TRUE, 0, NULL,
5908 FALSE, US"ETRN processing", &error);
5909 deliver_domain = NULL;
5912 log_write(0, LOG_MAIN|LOG_PANIC, "failed to set up ETRN command: %s",
5914 smtp_printf("458 Internal failure\r\n", FALSE);
5919 /* Else set up to call Exim with the -R option. */
5923 if (*smtp_cmd_data++ != '#')
5925 done = synprot_error(L_smtp_syntax_error, 501, NULL,
5926 US"argument must begin with #");
5929 etrn_command = US"exim -R";
5930 argv = CUSS child_exec_exim(CEE_RETURN_ARGV, TRUE, NULL, TRUE,
5931 *queue_name ? 4 : 2,
5932 US"-R", smtp_cmd_data,
5933 US"-MCG", queue_name);
5936 /* If we are host-testing, don't actually do anything. */
5942 debug_printf("ETRN command is: %s\n", etrn_command);
5943 debug_printf("ETRN command execution skipped\n");
5945 if (user_msg == NULL) smtp_printf("250 OK\r\n", FALSE);
5946 else smtp_user_msg(US"250", user_msg);
5951 /* If ETRN queue runs are to be serialized, check the database to
5952 ensure one isn't already running. */
5954 if (smtp_etrn_serialize && !enq_start(etrn_serialize_key, 1))
5956 smtp_printf("458 Already processing %s\r\n", FALSE, smtp_cmd_data);
5960 /* Fork a child process and run the command. We don't want to have to
5961 wait for the process at any point, so set SIGCHLD to SIG_IGN before
5962 forking. It should be set that way anyway for external incoming SMTP,
5963 but we save and restore to be tidy. If serialization is required, we
5964 actually run the command in yet another process, so we can wait for it
5965 to complete and then remove the serialization lock. */
5967 oldsignal = signal(SIGCHLD, SIG_IGN);
5969 if ((pid = exim_fork(US"etrn-command")) == 0)
5971 smtp_input = FALSE; /* This process is not associated with the */
5972 (void)fclose(smtp_in); /* SMTP call any more. */
5973 (void)fclose(smtp_out);
5975 signal(SIGCHLD, SIG_DFL); /* Want to catch child */
5977 /* If not serializing, do the exec right away. Otherwise, fork down
5978 into another process. */
5980 if ( !smtp_etrn_serialize
5981 || (pid = exim_fork(US"etrn-serialised-command")) == 0)
5983 DEBUG(D_exec) debug_print_argv(argv);
5984 exim_nullstd(); /* Ensure std{in,out,err} exist */
5985 /* argv[0] should be untainted, from child_exec_exim() */
5986 execv(CS argv[0], (char *const *)argv);
5987 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "exec of \"%s\" (ETRN) failed: %s",
5988 etrn_command, strerror(errno));
5989 _exit(EXIT_FAILURE); /* paranoia */
5992 /* Obey this if smtp_serialize and the 2nd fork yielded non-zero. That
5993 is, we are in the first subprocess, after forking again. All we can do
5994 for a failing fork is to log it. Otherwise, wait for the 2nd process to
5995 complete, before removing the serialization. */
5998 log_write(0, LOG_MAIN|LOG_PANIC, "2nd fork for serialized ETRN "
5999 "failed: %s", strerror(errno));
6003 DEBUG(D_any) debug_printf("waiting for serialized ETRN process %d\n",
6005 (void)wait(&status);
6006 DEBUG(D_any) debug_printf("serialized ETRN process %d ended\n",
6010 enq_end(etrn_serialize_key);
6011 exim_underbar_exit(EXIT_SUCCESS);
6014 /* Back in the top level SMTP process. Check that we started a subprocess
6015 and restore the signal state. */
6019 log_write(0, LOG_MAIN|LOG_PANIC, "fork of process for ETRN failed: %s",
6021 smtp_printf("458 Unable to fork process\r\n", FALSE);
6022 if (smtp_etrn_serialize) enq_end(etrn_serialize_key);
6026 smtp_printf("250 OK\r\n", FALSE);
6028 smtp_user_msg(US"250", user_msg);
6030 signal(SIGCHLD, oldsignal);
6035 done = synprot_error(L_smtp_syntax_error, 501, NULL,
6036 US"unexpected argument data");
6040 /* This currently happens only for NULLs, but could be extended. */
6043 done = synprot_error(L_smtp_syntax_error, 0, NULL, /* Just logs */
6044 US"NUL character(s) present (shown as '?')");
6045 smtp_printf("501 NUL characters are not allowed in SMTP commands\r\n",
6052 if (smtp_inend >= smtp_inbuffer + IN_BUFFER_SIZE)
6053 smtp_inend = smtp_inbuffer + IN_BUFFER_SIZE - 1;
6054 c = smtp_inend - smtp_inptr;
6055 if (c > 150) c = 150; /* limit logged amount */
6057 incomplete_transaction_log(US"sync failure");
6058 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP protocol synchronization error "
6059 "(next input sent too soon: pipelining was%s advertised): "
6060 "rejected \"%s\" %s next input=\"%s\"",
6061 f.smtp_in_pipelining_advertised ? "" : " not",
6062 smtp_cmd_buffer, host_and_ident(TRUE),
6063 string_printing(smtp_inptr));
6064 smtp_notquit_exit(US"synchronization-error", US"554",
6065 US"SMTP synchronization error");
6066 done = 1; /* Pretend eof - drops connection */
6070 case TOO_MANY_NONMAIL_CMD:
6071 s = smtp_cmd_buffer;
6072 while (*s != 0 && !isspace(*s)) s++;
6073 incomplete_transaction_log(US"too many non-mail commands");
6074 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
6075 "nonmail commands (last was \"%.*s\")", host_and_ident(FALSE),
6076 (int)(s - smtp_cmd_buffer), smtp_cmd_buffer);
6077 smtp_notquit_exit(US"bad-commands", US"554", US"Too many nonmail commands");
6078 done = 1; /* Pretend eof - drops connection */
6081 #ifdef SUPPORT_PROXY
6082 case PROXY_FAIL_IGNORE_CMD:
6083 smtp_printf("503 Command refused, required Proxy negotiation failed\r\n", FALSE);
6088 if (unknown_command_count++ >= smtp_max_unknown_commands)
6090 log_write(L_smtp_syntax_error, LOG_MAIN,
6091 "SMTP syntax error in \"%s\" %s %s",
6092 string_printing(smtp_cmd_buffer), host_and_ident(TRUE),
6093 US"unrecognized command");
6094 incomplete_transaction_log(US"unrecognized command");
6095 smtp_notquit_exit(US"bad-commands", US"500",
6096 US"Too many unrecognized commands");
6098 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
6099 "unrecognized commands (last was \"%s\")", host_and_ident(FALSE),
6100 string_printing(smtp_cmd_buffer));
6103 done = synprot_error(L_smtp_syntax_error, 500, NULL,
6104 US"unrecognized command");
6108 /* This label is used by goto's inside loops that want to break out to
6109 the end of the command-processing loop. */
6112 last_was_rej_mail = was_rej_mail; /* Remember some last commands for */
6113 last_was_rcpt = was_rcpt; /* protocol error handling */
6116 return done - 2; /* Convert yield values */
6122 authres_smtpauth(gstring * g)
6124 if (!sender_host_authenticated)
6127 g = string_append(g, 2, US";\n\tauth=pass (", sender_host_auth_pubname);
6129 if (Ustrcmp(sender_host_auth_pubname, "tls") == 0)
6130 g = authenticated_id
6131 ? string_append(g, 2, US") x509.auth=", authenticated_id)
6132 : string_cat(g, US") reason=x509.auth");
6134 g = authenticated_id
6135 ? string_append(g, 2, US") smtp.auth=", authenticated_id)
6136 : string_cat(g, US", no id saved)");
6138 if (authenticated_sender)
6139 g = string_append(g, 2, US" smtp.mailfrom=", authenticated_sender);
6147 /* End of smtp_in.c */