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 */
1192 proxy_debug(uschar * buf, unsigned start, unsigned end)
1194 debug_printf("PROXY<<");
1195 while (start < end) debug_printf(" %02x", buf[start++]);
1200 /*************************************************
1201 * Setup host for proxy protocol *
1202 *************************************************/
1203 /* The function configures the connection based on a header from the
1204 inbound host to use Proxy Protocol. The specification is very exact
1205 so exit with an error if do not find the exact required pieces. This
1206 includes an incorrect number of spaces separating args.
1209 Returns: Boolean success
1213 setup_proxy_protocol_host()
1225 struct { /* TCP/UDP over IPv4, len = 12 */
1231 struct { /* TCP/UDP over IPv6, len = 36 */
1232 uint8_t src_addr[16];
1233 uint8_t dst_addr[16];
1237 struct { /* AF_UNIX sockets, len = 216 */
1238 uschar src_addr[108];
1239 uschar dst_addr[108];
1245 /* Temp variables used in PPv2 address:port parsing */
1247 char tmpip[INET_ADDRSTRLEN];
1248 struct sockaddr_in tmpaddr;
1249 char tmpip6[INET6_ADDRSTRLEN];
1250 struct sockaddr_in6 tmpaddr6;
1252 /* We can't read "all data until end" because while SMTP is
1253 server-speaks-first, the TLS handshake is client-speaks-first, so for
1254 TLS-on-connect ports the proxy protocol header will usually be immediately
1255 followed by a TLS handshake, and with N TLS libraries, we can't reliably
1256 reinject data for reading by those. So instead we first read "enough to be
1257 safely read within the header, and figure out how much more to read".
1258 For v1 we will later read to the end-of-line, for v2 we will read based upon
1261 The v2 sig is 12 octets, and another 4 gets us the length, so we know how much
1262 data is needed total. For v1, where the line looks like:
1263 PROXY TCPn L3src L3dest SrcPort DestPort \r\n
1265 However, for v1 there's also `PROXY UNKNOWN\r\n` which is only 15 octets.
1266 We seem to support that. So, if we read 14 octets then we can tell if we're
1267 v2 or v1. If we're v1, we can continue reading as normal.
1269 If we're v2, we can't slurp up the entire header. We need the length in the
1270 15th & 16th octets, then to read everything after that.
1272 So to safely handle v1 and v2, with client-sent-first supported correctly,
1273 we have to do a minimum of 3 read calls, not 1. Eww.
1276 # define PROXY_INITIAL_READ 14
1277 # define PROXY_V2_HEADER_SIZE 16
1278 # if PROXY_INITIAL_READ > PROXY_V2_HEADER_SIZE
1279 # error Code bug in sizes of data to read for proxy usage
1284 int fd = fileno(smtp_in);
1285 const char v2sig[12] = "\x0D\x0A\x0D\x0A\x00\x0D\x0A\x51\x55\x49\x54\x0A";
1286 uschar * iptype; /* To display debug info */
1287 socklen_t vslen = sizeof(struct timeval);
1290 os_non_restarting_signal(SIGALRM, command_timeout_handler);
1291 ALARM(proxy_protocol_timeout);
1295 /* The inbound host was declared to be a Proxy Protocol host, so
1296 don't do a PEEK into the data, actually slurp up enough to be
1297 "safe". Can't take it all because TLS-on-connect clients follow
1298 immediately with TLS handshake. */
1299 ret = read(fd, &hdr, PROXY_INITIAL_READ);
1300 } while (ret == -1 && errno == EINTR && !had_command_timeout);
1304 DEBUG(D_receive) proxy_debug(US &hdr, 0, ret);
1306 /* For v2, handle reading the length, and then the rest. */
1307 if ((ret == PROXY_INITIAL_READ) && (memcmp(&hdr.v2, v2sig, sizeof(v2sig)) == 0))
1312 DEBUG(D_receive) debug_printf("v2\n");
1314 /* First get the length fields. */
1317 retmore = read(fd, (uschar*)&hdr + ret, PROXY_V2_HEADER_SIZE - PROXY_INITIAL_READ);
1318 } while (retmore == -1 && errno == EINTR && !had_command_timeout);
1321 DEBUG(D_receive) proxy_debug(US &hdr, ret, ret + retmore);
1325 ver = (hdr.v2.ver_cmd & 0xf0) >> 4;
1327 /* May 2014: haproxy combined the version and command into one byte to
1328 allow two full bytes for the length field in order to proxy SSL
1329 connections. SSL Proxy is not supported in this version of Exim, but
1330 must still separate values here. */
1334 DEBUG(D_receive) debug_printf("Invalid Proxy Protocol version: %d\n", ver);
1338 /* The v2 header will always be 16 bytes per the spec. */
1339 size = 16 + ntohs(hdr.v2.len);
1340 DEBUG(D_receive) debug_printf("Detected PROXYv2 header, size %d (limit %d)\n",
1341 size, (int)sizeof(hdr));
1343 /* We should now have 16 octets (PROXY_V2_HEADER_SIZE), and we know the total
1344 amount that we need. Double-check that the size is not unreasonable, then
1346 if (size > sizeof(hdr))
1348 DEBUG(D_receive) debug_printf("PROXYv2 header size unreasonably large; security attack?\n");
1356 retmore = read(fd, (uschar*)&hdr + ret, size-ret);
1357 } while (retmore == -1 && errno == EINTR && !had_command_timeout);
1360 DEBUG(D_receive) proxy_debug(US &hdr, ret, ret + retmore);
1362 DEBUG(D_receive) debug_printf("PROXYv2: have %d/%d required octets\n", ret, size);
1363 } while (ret < size);
1365 } /* end scope for getting rest of data for v2 */
1367 /* At this point: if PROXYv2, we've read the exact size required for all data;
1368 if PROXYv1 then we've read "less than required for any valid line" and should
1371 if (ret >= 16 && memcmp(&hdr.v2, v2sig, 12) == 0)
1373 uint8_t cmd = (hdr.v2.ver_cmd & 0x0f);
1377 case 0x01: /* PROXY command */
1380 case 0x11: /* TCPv4 address type */
1382 tmpaddr.sin_addr.s_addr = hdr.v2.addr.ip4.src_addr;
1383 inet_ntop(AF_INET, &tmpaddr.sin_addr, CS &tmpip, sizeof(tmpip));
1384 if (!string_is_ip_address(US tmpip, NULL))
1386 DEBUG(D_receive) debug_printf("Invalid %s source IP\n", iptype);
1389 proxy_local_address = sender_host_address;
1390 sender_host_address = string_copy(US tmpip);
1391 tmpport = ntohs(hdr.v2.addr.ip4.src_port);
1392 proxy_local_port = sender_host_port;
1393 sender_host_port = tmpport;
1394 /* Save dest ip/port */
1395 tmpaddr.sin_addr.s_addr = hdr.v2.addr.ip4.dst_addr;
1396 inet_ntop(AF_INET, &tmpaddr.sin_addr, CS &tmpip, sizeof(tmpip));
1397 if (!string_is_ip_address(US tmpip, NULL))
1399 DEBUG(D_receive) debug_printf("Invalid %s dest port\n", iptype);
1402 proxy_external_address = string_copy(US tmpip);
1403 tmpport = ntohs(hdr.v2.addr.ip4.dst_port);
1404 proxy_external_port = tmpport;
1406 case 0x21: /* TCPv6 address type */
1408 memmove(tmpaddr6.sin6_addr.s6_addr, hdr.v2.addr.ip6.src_addr, 16);
1409 inet_ntop(AF_INET6, &tmpaddr6.sin6_addr, CS &tmpip6, sizeof(tmpip6));
1410 if (!string_is_ip_address(US tmpip6, NULL))
1412 DEBUG(D_receive) debug_printf("Invalid %s source IP\n", iptype);
1415 proxy_local_address = sender_host_address;
1416 sender_host_address = string_copy(US tmpip6);
1417 tmpport = ntohs(hdr.v2.addr.ip6.src_port);
1418 proxy_local_port = sender_host_port;
1419 sender_host_port = tmpport;
1420 /* Save dest ip/port */
1421 memmove(tmpaddr6.sin6_addr.s6_addr, hdr.v2.addr.ip6.dst_addr, 16);
1422 inet_ntop(AF_INET6, &tmpaddr6.sin6_addr, CS &tmpip6, sizeof(tmpip6));
1423 if (!string_is_ip_address(US tmpip6, NULL))
1425 DEBUG(D_receive) debug_printf("Invalid %s dest port\n", iptype);
1428 proxy_external_address = string_copy(US tmpip6);
1429 tmpport = ntohs(hdr.v2.addr.ip6.dst_port);
1430 proxy_external_port = tmpport;
1434 debug_printf("Unsupported PROXYv2 connection type: 0x%02x\n",
1438 /* Unsupported protocol, keep local connection address */
1440 case 0x00: /* LOCAL command */
1441 /* Keep local connection address for LOCAL */
1446 debug_printf("Unsupported PROXYv2 command: 0x%x\n", cmd);
1450 else if (ret >= 8 && memcmp(hdr.v1.line, "PROXY", 5) == 0)
1454 uschar *sp; /* Utility variables follow */
1459 /* get the rest of the line */
1460 r2 = swallow_until_crlf(fd, (uschar*)&hdr, ret, sizeof(hdr)-ret);
1465 p = string_copy(hdr.v1.line);
1466 end = memchr(p, '\r', ret - 1);
1468 if (!end || (end == (uschar*)&hdr + ret) || end[1] != '\n')
1470 DEBUG(D_receive) debug_printf("Partial or invalid PROXY header\n");
1473 *end = '\0'; /* Terminate the string */
1474 size = end + 2 - p; /* Skip header + CRLF */
1475 DEBUG(D_receive) debug_printf("Detected PROXYv1 header\n");
1476 DEBUG(D_receive) debug_printf("Bytes read not within PROXY header: %d\n", ret - size);
1477 /* Step through the string looking for the required fields. Ensure
1478 strict adherence to required formatting, exit for any error. */
1480 if (!isspace(*(p++)))
1482 DEBUG(D_receive) debug_printf("Missing space after PROXY command\n");
1485 if (!Ustrncmp(p, CCS"TCP4", 4))
1487 else if (!Ustrncmp(p,CCS"TCP6", 4))
1489 else if (!Ustrncmp(p,CCS"UNKNOWN", 7))
1491 iptype = US"Unknown";
1496 DEBUG(D_receive) debug_printf("Invalid TCP type\n");
1500 p += Ustrlen(iptype);
1501 if (!isspace(*(p++)))
1503 DEBUG(D_receive) debug_printf("Missing space after TCP4/6 command\n");
1506 /* Find the end of the arg */
1507 if ((sp = Ustrchr(p, ' ')) == NULL)
1510 debug_printf("Did not find proxied src %s\n", iptype);
1514 if(!string_is_ip_address(p, NULL))
1517 debug_printf("Proxied src arg is not an %s address\n", iptype);
1520 proxy_local_address = sender_host_address;
1521 sender_host_address = p;
1523 if ((sp = Ustrchr(p, ' ')) == NULL)
1526 debug_printf("Did not find proxy dest %s\n", iptype);
1530 if(!string_is_ip_address(p, NULL))
1533 debug_printf("Proxy dest arg is not an %s address\n", iptype);
1536 proxy_external_address = p;
1538 if ((sp = Ustrchr(p, ' ')) == NULL)
1540 DEBUG(D_receive) debug_printf("Did not find proxied src port\n");
1544 tmp_port = strtol(CCS p, &endc, 10);
1545 if (*endc || tmp_port == 0)
1548 debug_printf("Proxied src port '%s' not an integer\n", p);
1551 proxy_local_port = sender_host_port;
1552 sender_host_port = tmp_port;
1554 if ((sp = Ustrchr(p, '\0')) == NULL)
1556 DEBUG(D_receive) debug_printf("Did not find proxy dest port\n");
1559 tmp_port = strtol(CCS p, &endc, 10);
1560 if (*endc || tmp_port == 0)
1563 debug_printf("Proxy dest port '%s' not an integer\n", p);
1566 proxy_external_port = tmp_port;
1567 /* Already checked for /r /n above. Good V1 header received. */
1571 /* Wrong protocol */
1572 DEBUG(D_receive) debug_printf("Invalid proxy protocol version negotiation\n");
1573 (void) swallow_until_crlf(fd, (uschar*)&hdr, ret, sizeof(hdr)-ret);
1579 debug_printf("Valid %s sender from Proxy Protocol header\n", iptype);
1580 yield = proxy_session;
1582 /* Don't flush any potential buffer contents. Any input on proxyfail
1583 should cause a synchronization failure */
1586 DEBUG(D_receive) if (had_command_timeout)
1587 debug_printf("Timeout while reading proxy header\n");
1592 sender_host_name = NULL;
1593 (void) host_name_lookup();
1594 host_build_sender_fullhost();
1598 f.proxy_session_failed = TRUE;
1600 debug_printf("Failure to extract proxied host, only QUIT allowed\n");
1606 #endif /*SUPPORT_PROXY*/
1608 /*************************************************
1609 * Read one command line *
1610 *************************************************/
1612 /* Strictly, SMTP commands coming over the net are supposed to end with CRLF.
1613 There are sites that don't do this, and in any case internal SMTP probably
1614 should check only for LF. Consequently, we check here for LF only. The line
1615 ends up with [CR]LF removed from its end. If we get an overlong line, treat as
1616 an unknown command. The command is read into the global smtp_cmd_buffer so that
1617 it is available via $smtp_command.
1619 The character reading routine sets up a timeout for each block actually read
1620 from the input (which may contain more than one command). We set up a special
1621 signal handler that closes down the session on a timeout. Control does not
1622 return when it runs.
1625 check_sync if TRUE, check synchronization rules if global option is TRUE
1626 buffer_lim maximum to buffer in lower layer
1628 Returns: a code identifying the command (enumerated above)
1632 smtp_read_command(BOOL check_sync, unsigned buffer_lim)
1636 BOOL hadnull = FALSE;
1638 had_command_timeout = 0;
1639 os_non_restarting_signal(SIGALRM, command_timeout_handler);
1641 while ((c = (receive_getc)(buffer_lim)) != '\n' && c != EOF)
1643 if (ptr >= SMTP_CMD_BUFFER_SIZE)
1645 os_non_restarting_signal(SIGALRM, sigalrm_handler);
1653 smtp_cmd_buffer[ptr++] = c;
1656 receive_linecount++; /* For BSMTP errors */
1657 os_non_restarting_signal(SIGALRM, sigalrm_handler);
1659 /* If hit end of file, return pseudo EOF command. Whether we have a
1660 part-line already read doesn't matter, since this is an error state. */
1662 if (c == EOF) return EOF_CMD;
1664 /* Remove any CR and white space at the end of the line, and terminate the
1667 while (ptr > 0 && isspace(smtp_cmd_buffer[ptr-1])) ptr--;
1668 smtp_cmd_buffer[ptr] = 0;
1670 DEBUG(D_receive) debug_printf("SMTP<< %s\n", smtp_cmd_buffer);
1672 /* NULLs are not allowed in SMTP commands */
1674 if (hadnull) return BADCHAR_CMD;
1676 /* Scan command list and return identity, having set the data pointer
1677 to the start of the actual data characters. Check for SMTP synchronization
1680 for (smtp_cmd_list * p = cmd_list; p < cmd_list_end; p++)
1682 #ifdef SUPPORT_PROXY
1683 /* Only allow QUIT command if Proxy Protocol parsing failed */
1684 if (proxy_session && f.proxy_session_failed && p->cmd != QUIT_CMD)
1688 && strncmpic(smtp_cmd_buffer, US p->name, p->len) == 0
1689 && ( smtp_cmd_buffer[p->len-1] == ':' /* "mail from:" or "rcpt to:" */
1690 || smtp_cmd_buffer[p->len] == 0
1691 || smtp_cmd_buffer[p->len] == ' '
1694 if ( smtp_inptr < smtp_inend /* Outstanding input */
1695 && p->cmd < sync_cmd_limit /* Command should sync */
1696 && check_sync /* Local flag set */
1697 && smtp_enforce_sync /* Global flag set */
1698 && sender_host_address != NULL /* Not local input */
1699 && !f.sender_host_notsocket /* Really is a socket */
1703 /* The variables $smtp_command and $smtp_command_argument point into the
1704 unmodified input buffer. A copy of the latter is taken for actual
1705 processing, so that it can be chopped up into separate parts if necessary,
1706 for example, when processing a MAIL command options such as SIZE that can
1707 follow the sender address. */
1709 smtp_cmd_argument = smtp_cmd_buffer + p->len;
1710 while (isspace(*smtp_cmd_argument)) smtp_cmd_argument++;
1711 Ustrcpy(smtp_data_buffer, smtp_cmd_argument);
1712 smtp_cmd_data = smtp_data_buffer;
1714 /* Count non-mail commands from those hosts that are controlled in this
1715 way. The default is all hosts. We don't waste effort checking the list
1716 until we get a non-mail command, but then cache the result to save checking
1717 again. If there's a DEFER while checking the host, assume it's in the list.
1719 Note that one instance of RSET, EHLO/HELO, and STARTTLS is allowed at the
1720 start of each incoming message by fiddling with the value in the table. */
1722 if (!p->is_mail_cmd)
1724 if (count_nonmail == TRUE_UNSET) count_nonmail =
1725 verify_check_host(&smtp_accept_max_nonmail_hosts) != FAIL;
1726 if (count_nonmail && ++nonmail_command_count > smtp_accept_max_nonmail)
1727 return TOO_MANY_NONMAIL_CMD;
1730 /* If there is data for a command that does not expect it, generate the
1733 return (p->has_arg || *smtp_cmd_data == 0)? p->cmd : BADARG_CMD;
1737 #ifdef SUPPORT_PROXY
1738 /* Only allow QUIT command if Proxy Protocol parsing failed */
1739 if (proxy_session && f.proxy_session_failed)
1740 return PROXY_FAIL_IGNORE_CMD;
1743 /* Enforce synchronization for unknown commands */
1745 if ( smtp_inptr < smtp_inend /* Outstanding input */
1746 && check_sync /* Local flag set */
1747 && smtp_enforce_sync /* Global flag set */
1748 && sender_host_address /* Not local input */
1749 && !f.sender_host_notsocket /* Really is a socket */
1758 /*************************************************
1759 * Forced closedown of call *
1760 *************************************************/
1762 /* This function is called from log.c when Exim is dying because of a serious
1763 disaster, and also from some other places. If an incoming non-batched SMTP
1764 channel is open, it swallows the rest of the incoming message if in the DATA
1765 phase, sends the reply string, and gives an error to all subsequent commands
1766 except QUIT. The existence of an SMTP call is detected by the non-NULLness of
1770 message SMTP reply string to send, excluding the code
1776 smtp_closedown(uschar * message)
1778 if (!smtp_in || smtp_batched_input) return;
1779 receive_swallow_smtp();
1780 smtp_printf("421 %s\r\n", FALSE, message);
1782 for (;;) switch(smtp_read_command(FALSE, GETC_BUFFER_UNLIMITED))
1788 f.smtp_in_quit = TRUE;
1789 smtp_printf("221 %s closing connection\r\n", FALSE, smtp_active_hostname);
1794 smtp_printf("250 Reset OK\r\n", FALSE);
1798 smtp_printf("421 %s\r\n", FALSE, message);
1806 /*************************************************
1807 * Set up connection info for logging *
1808 *************************************************/
1810 /* This function is called when logging information about an SMTP connection.
1811 It sets up appropriate source information, depending on the type of connection.
1812 If sender_fullhost is NULL, we are at a very early stage of the connection;
1813 just use the IP address.
1816 Returns: a string describing the connection
1820 smtp_get_connection_info(void)
1822 const uschar * hostname = sender_fullhost
1823 ? sender_fullhost : sender_host_address;
1826 return string_sprintf("SMTP connection from %s", hostname);
1828 if (f.sender_host_unknown || f.sender_host_notsocket)
1829 return string_sprintf("SMTP connection from %s", sender_ident);
1832 return string_sprintf("SMTP connection from %s (via inetd)", hostname);
1834 if (LOGGING(incoming_interface) && interface_address)
1835 return string_sprintf("SMTP connection from %s I=[%s]:%d", hostname,
1836 interface_address, interface_port);
1838 return string_sprintf("SMTP connection from %s", hostname);
1844 /* Append TLS-related information to a log line
1847 g String under construction: allocated string to extend, or NULL
1849 Returns: Allocated string or NULL
1852 s_tlslog(gstring * g)
1854 if (LOGGING(tls_cipher) && tls_in.cipher)
1856 g = string_append(g, 2, US" X=", tls_in.cipher);
1857 #ifndef DISABLE_TLS_RESUME
1858 if (LOGGING(tls_resumption) && tls_in.resumption & RESUME_USED)
1859 g = string_catn(g, US"*", 1);
1862 if (LOGGING(tls_certificate_verified) && tls_in.cipher)
1863 g = string_append(g, 2, US" CV=", tls_in.certificate_verified? "yes":"no");
1864 if (LOGGING(tls_peerdn) && tls_in.peerdn)
1865 g = string_append(g, 3, US" DN=\"", string_printing(tls_in.peerdn), US"\"");
1866 if (LOGGING(tls_sni) && tls_in.sni)
1867 g = string_append(g, 2, US" SNI=", string_printing2(tls_in.sni, SP_TAB|SP_SPACE));
1875 s_connhad_log(gstring * g)
1877 const uschar * sep = smtp_connection_had[SMTP_HBUFF_SIZE-1] != SCH_NONE
1878 ? US" C=..." : US" C=";
1880 for (int i = smtp_ch_index; i < SMTP_HBUFF_SIZE; i++)
1881 if (smtp_connection_had[i] != SCH_NONE)
1883 g = string_append(g, 2, sep, smtp_names[smtp_connection_had[i]]);
1886 for (int i = 0; i < smtp_ch_index; i++, sep = US",")
1887 g = string_append(g, 2, sep, smtp_names[smtp_connection_had[i]]);
1892 /*************************************************
1893 * Log lack of MAIL if so configured *
1894 *************************************************/
1896 /* This function is called when an SMTP session ends. If the log selector
1897 smtp_no_mail is set, write a log line giving some details of what has happened
1898 in the SMTP session.
1905 smtp_log_no_mail(void)
1910 if (smtp_mailcmd_count > 0 || !LOGGING(smtp_no_mail))
1913 if (sender_host_authenticated)
1915 g = string_append(g, 2, US" A=", sender_host_authenticated);
1916 if (authenticated_id) g = string_append(g, 2, US":", authenticated_id);
1923 g = s_connhad_log(g);
1925 if (!(s = string_from_gstring(g))) s = US"";
1927 log_write(0, LOG_MAIN, "no MAIL in %sSMTP connection from %s D=%s%s",
1928 f.tcp_in_fastopen ? f.tcp_in_fastopen_data ? US"TFO* " : US"TFO " : US"",
1929 host_and_ident(FALSE), string_timesince(&smtp_connection_start), s);
1933 /* Return list of recent smtp commands */
1938 gstring * list = NULL;
1941 for (int i = smtp_ch_index; i < SMTP_HBUFF_SIZE; i++)
1942 if (smtp_connection_had[i] != SCH_NONE)
1943 list = string_append_listele(list, ',', smtp_names[smtp_connection_had[i]]);
1945 for (int i = 0; i < smtp_ch_index; i++)
1946 list = string_append_listele(list, ',', smtp_names[smtp_connection_had[i]]);
1948 s = string_from_gstring(list);
1949 return s ? s : US"";
1955 /*************************************************
1956 * Check HELO line and set sender_helo_name *
1957 *************************************************/
1959 /* Check the format of a HELO line. The data for HELO/EHLO is supposed to be
1960 the domain name of the sending host, or an ip literal in square brackets. The
1961 argument is placed in sender_helo_name, which is in malloc store, because it
1962 must persist over multiple incoming messages. If helo_accept_junk is set, this
1963 host is permitted to send any old junk (needed for some broken hosts).
1964 Otherwise, helo_allow_chars can be used for rogue characters in general
1965 (typically people want to let in underscores).
1968 s the data portion of the line (already past any white space)
1970 Returns: TRUE or FALSE
1974 check_helo(uschar *s)
1977 uschar *end = s + Ustrlen(s);
1978 BOOL yield = fl.helo_accept_junk;
1980 /* Discard any previous helo name */
1982 sender_helo_name = NULL;
1984 /* Skip tests if junk is permitted. */
1988 /* Allow the new standard form for IPv6 address literals, namely,
1989 [IPv6:....], and because someone is bound to use it, allow an equivalent
1990 IPv4 form. Allow plain addresses as well. */
1997 if (strncmpic(s, US"[IPv6:", 6) == 0)
1998 yield = (string_is_ip_address(s+6, NULL) == 6);
1999 else if (strncmpic(s, US"[IPv4:", 6) == 0)
2000 yield = (string_is_ip_address(s+6, NULL) == 4);
2002 yield = (string_is_ip_address(s+1, NULL) != 0);
2007 /* Non-literals must be alpha, dot, hyphen, plus any non-valid chars
2008 that have been configured (usually underscore - sigh). */
2011 for (yield = TRUE; *s; s++)
2012 if (!isalnum(*s) && *s != '.' && *s != '-' &&
2013 Ustrchr(helo_allow_chars, *s) == NULL)
2019 /* Save argument if OK */
2021 if (yield) sender_helo_name = string_copy_perm(start, TRUE);
2029 /*************************************************
2030 * Extract SMTP command option *
2031 *************************************************/
2033 /* This function picks the next option setting off the end of smtp_cmd_data. It
2034 is called for MAIL FROM and RCPT TO commands, to pick off the optional ESMTP
2035 things that can appear there.
2038 name point this at the name
2039 value point this at the data string
2041 Returns: TRUE if found an option
2045 extract_option(uschar **name, uschar **value)
2049 if (Ustrlen(smtp_cmd_data) <= 0) return FALSE;
2050 v = smtp_cmd_data + Ustrlen(smtp_cmd_data) - 1;
2051 while (v > smtp_cmd_data && isspace(*v)) v--;
2054 while (v > smtp_cmd_data && *v != '=' && !isspace(*v))
2056 /* Take care to not stop at a space embedded in a quoted local-part */
2059 do v--; while (v > smtp_cmd_data && *v != '"');
2060 if (v <= smtp_cmd_data) return FALSE;
2064 if (v <= smtp_cmd_data) return FALSE;
2069 while (n > smtp_cmd_data && isalpha(n[-1])) n--;
2070 /* RFC says SP, but TAB seen in wild and other major MTAs accept it */
2071 if (n <= smtp_cmd_data || !isspace(n[-1])) return FALSE;
2088 /*************************************************
2089 * Reset for new message *
2090 *************************************************/
2092 /* This function is called whenever the SMTP session is reset from
2093 within either of the setup functions; also from the daemon loop.
2095 Argument: the stacking pool storage reset point
2100 smtp_reset(void *reset_point)
2102 recipients_list = NULL;
2103 rcpt_count = rcpt_defer_count = rcpt_fail_count =
2104 raw_recipients_count = recipients_count = recipients_list_max = 0;
2105 message_linecount = 0;
2107 message_body = message_body_end = NULL;
2108 acl_added_headers = NULL;
2109 acl_removed_headers = NULL;
2110 f.queue_only_policy = FALSE;
2111 rcpt_smtp_response = NULL;
2112 fl.rcpt_smtp_response_same = TRUE;
2113 fl.rcpt_in_progress = FALSE;
2114 f.deliver_freeze = FALSE; /* Can be set by ACL */
2115 freeze_tell = freeze_tell_config; /* Can be set by ACL */
2116 fake_response = OK; /* Can be set by ACL */
2117 #ifdef WITH_CONTENT_SCAN
2118 f.no_mbox_unspool = FALSE; /* Can be set by ACL */
2120 f.submission_mode = FALSE; /* Can be set by ACL */
2121 f.suppress_local_fixups = f.suppress_local_fixups_default; /* Can be set by ACL */
2122 f.active_local_from_check = local_from_check; /* Can be set by ACL */
2123 f.active_local_sender_retain = local_sender_retain; /* Can be set by ACL */
2124 sending_ip_address = NULL;
2125 return_path = sender_address = NULL;
2126 deliver_localpart_data = deliver_domain_data =
2127 recipient_data = sender_data = NULL; /* Can be set by ACL */
2128 recipient_verify_failure = NULL;
2129 deliver_localpart_parent = deliver_localpart_orig = NULL;
2130 deliver_domain_parent = deliver_domain_orig = NULL;
2131 callout_address = NULL;
2132 submission_name = NULL; /* Can be set by ACL */
2133 raw_sender = NULL; /* After SMTP rewrite, before qualifying */
2134 sender_address_unrewritten = NULL; /* Set only after verify rewrite */
2135 sender_verified_list = NULL; /* No senders verified */
2136 memset(sender_address_cache, 0, sizeof(sender_address_cache));
2137 memset(sender_domain_cache, 0, sizeof(sender_domain_cache));
2139 authenticated_sender = NULL;
2140 #ifdef EXPERIMENTAL_BRIGHTMAIL
2142 bmi_verdicts = NULL;
2144 dnslist_domain = dnslist_matched = NULL;
2146 spf_header_comment = spf_received = spf_result = spf_smtp_comment = NULL;
2147 spf_result_guessed = FALSE;
2149 #ifndef DISABLE_DKIM
2150 dkim_cur_signer = dkim_signers =
2151 dkim_signing_domain = dkim_signing_selector = dkim_signatures = NULL;
2152 dkim_cur_signer = dkim_signers = dkim_signing_domain = dkim_signing_selector = NULL;
2153 f.dkim_disable_verify = FALSE;
2154 dkim_collect_input = 0;
2155 dkim_verify_overall = dkim_verify_status = dkim_verify_reason = NULL;
2156 dkim_key_length = 0;
2158 #ifdef SUPPORT_DMARC
2159 f.dmarc_has_been_checked = f.dmarc_disable_verify = f.dmarc_enable_forensic = FALSE;
2160 dmarc_domain_policy = dmarc_status = dmarc_status_text =
2161 dmarc_used_domain = NULL;
2163 #ifdef EXPERIMENTAL_ARC
2164 arc_state = arc_state_reason = NULL;
2165 arc_received_instance = 0;
2169 deliver_host = deliver_host_address = NULL; /* Can be set by ACL */
2170 #ifndef DISABLE_PRDR
2171 prdr_requested = FALSE;
2174 message_smtputf8 = FALSE;
2176 #ifdef WITH_CONTENT_SCAN
2179 body_linecount = body_zerocount = 0;
2181 lookup_value = NULL; /* Can be set by ACL */
2182 sender_rate = sender_rate_limit = sender_rate_period = NULL;
2183 ratelimiters_mail = NULL; /* Updated by ratelimit ACL condition */
2184 /* Note that ratelimiters_conn persists across resets. */
2186 /* Reset message ACL variables */
2190 /* Warning log messages are saved in malloc store. They are saved to avoid
2191 repetition in the same message, but it seems right to repeat them for different
2194 while (acl_warn_logged)
2196 string_item *this = acl_warn_logged;
2197 acl_warn_logged = acl_warn_logged->next;
2202 store_reset(reset_point);
2205 return store_mark();
2212 /*************************************************
2213 * Initialize for incoming batched SMTP message *
2214 *************************************************/
2216 /* This function is called from smtp_setup_msg() in the case when
2217 smtp_batched_input is true. This happens when -bS is used to pass a whole batch
2218 of messages in one file with SMTP commands between them. All errors must be
2219 reported by sending a message, and only MAIL FROM, RCPT TO, and DATA are
2220 relevant. After an error on a sender, or an invalid recipient, the remainder
2221 of the message is skipped. The value of received_protocol is already set.
2224 Returns: > 0 message successfully started (reached DATA)
2225 = 0 QUIT read or end of file reached
2226 < 0 should not occur
2230 smtp_setup_batch_msg(void)
2233 rmark reset_point = store_mark();
2235 /* Save the line count at the start of each transaction - single commands
2236 like HELO and RSET count as whole transactions. */
2238 bsmtp_transaction_linecount = receive_linecount;
2240 if ((receive_feof)()) return 0; /* Treat EOF as QUIT */
2242 cancel_cutthrough_connection(TRUE, US"smtp_setup_batch_msg");
2243 reset_point = smtp_reset(reset_point); /* Reset for start of message */
2245 /* Deal with SMTP commands. This loop is exited by setting done to a POSITIVE
2246 value. The values are 2 larger than the required yield of the function. */
2251 uschar *recipient = NULL;
2252 int start, end, sender_domain, recipient_domain;
2254 switch(smtp_read_command(FALSE, GETC_BUFFER_UNLIMITED))
2256 /* The HELO/EHLO commands set sender_address_helo if they have
2257 valid data; otherwise they are ignored, except that they do
2258 a reset of the state. */
2263 check_helo(smtp_cmd_data);
2267 cancel_cutthrough_connection(TRUE, US"RSET received");
2268 reset_point = smtp_reset(reset_point);
2269 bsmtp_transaction_linecount = receive_linecount;
2273 /* The MAIL FROM command requires an address as an operand. All we
2274 do here is to parse it for syntactic correctness. The form "<>" is
2275 a special case which converts into an empty string. The start/end
2276 pointers in the original are not used further for this address, as
2277 it is the canonical extracted address which is all that is kept. */
2280 smtp_mailcmd_count++; /* Count for no-mail log */
2282 /* The function moan_smtp_batch() does not return. */
2283 moan_smtp_batch(smtp_cmd_buffer, "503 Sender already given");
2285 if (smtp_cmd_data[0] == 0)
2286 /* The function moan_smtp_batch() does not return. */
2287 moan_smtp_batch(smtp_cmd_buffer, "501 MAIL FROM must have an address operand");
2289 /* Reset to start of message */
2291 cancel_cutthrough_connection(TRUE, US"MAIL received");
2292 reset_point = smtp_reset(reset_point);
2294 /* Apply SMTP rewrite */
2296 raw_sender = rewrite_existflags & rewrite_smtp
2297 /* deconst ok as smtp_cmd_data was not const */
2298 ? US rewrite_one(smtp_cmd_data, rewrite_smtp|rewrite_smtp_sender, NULL,
2299 FALSE, US"", global_rewrite_rules)
2302 /* Extract the address; the TRUE flag allows <> as valid */
2305 parse_extract_address(raw_sender, &errmess, &start, &end, &sender_domain,
2309 /* The function moan_smtp_batch() does not return. */
2310 moan_smtp_batch(smtp_cmd_buffer, "501 %s", errmess);
2312 sender_address = string_copy(raw_sender);
2314 /* Qualify unqualified sender addresses if permitted to do so. */
2317 && sender_address[0] != 0 && sender_address[0] != '@')
2318 if (f.allow_unqualified_sender)
2320 /* deconst ok as sender_address was not const */
2321 sender_address = US rewrite_address_qualify(sender_address, FALSE);
2322 DEBUG(D_receive) debug_printf("unqualified address %s accepted "
2323 "and rewritten\n", raw_sender);
2325 /* The function moan_smtp_batch() does not return. */
2327 moan_smtp_batch(smtp_cmd_buffer, "501 sender address must contain "
2332 /* The RCPT TO command requires an address as an operand. All we do
2333 here is to parse it for syntactic correctness. There may be any number
2334 of RCPT TO commands, specifying multiple senders. We build them all into
2335 a data structure that is in argc/argv format. The start/end values
2336 given by parse_extract_address are not used, as we keep only the
2337 extracted address. */
2340 if (!sender_address)
2341 /* The function moan_smtp_batch() does not return. */
2342 moan_smtp_batch(smtp_cmd_buffer, "503 No sender yet given");
2344 if (smtp_cmd_data[0] == 0)
2345 /* The function moan_smtp_batch() does not return. */
2346 moan_smtp_batch(smtp_cmd_buffer,
2347 "501 RCPT TO must have an address operand");
2349 /* Check maximum number allowed */
2351 if (recipients_max > 0 && recipients_count + 1 > recipients_max)
2352 /* The function moan_smtp_batch() does not return. */
2353 moan_smtp_batch(smtp_cmd_buffer, "%s too many recipients",
2354 recipients_max_reject? "552": "452");
2356 /* Apply SMTP rewrite, then extract address. Don't allow "<>" as a
2357 recipient address */
2359 recipient = rewrite_existflags & rewrite_smtp
2360 /* deconst ok as smtp_cmd_data was not const */
2361 ? US rewrite_one(smtp_cmd_data, rewrite_smtp, NULL, FALSE, US"",
2362 global_rewrite_rules)
2365 recipient = parse_extract_address(recipient, &errmess, &start, &end,
2366 &recipient_domain, FALSE);
2369 /* The function moan_smtp_batch() does not return. */
2370 moan_smtp_batch(smtp_cmd_buffer, "501 %s", errmess);
2372 /* If the recipient address is unqualified, qualify it if permitted. Then
2373 add it to the list of recipients. */
2375 if (!recipient_domain)
2376 if (f.allow_unqualified_recipient)
2378 DEBUG(D_receive) debug_printf("unqualified address %s accepted\n",
2380 /* deconst ok as recipient was not const */
2381 recipient = US rewrite_address_qualify(recipient, TRUE);
2383 /* The function moan_smtp_batch() does not return. */
2385 moan_smtp_batch(smtp_cmd_buffer,
2386 "501 recipient address must contain a domain");
2388 receive_add_recipient(recipient, -1);
2392 /* The DATA command is legal only if it follows successful MAIL FROM
2393 and RCPT TO commands. This function is complete when a valid DATA
2394 command is encountered. */
2397 if (!sender_address || recipients_count <= 0)
2398 /* The function moan_smtp_batch() does not return. */
2399 if (!sender_address)
2400 moan_smtp_batch(smtp_cmd_buffer,
2401 "503 MAIL FROM:<sender> command must precede DATA");
2403 moan_smtp_batch(smtp_cmd_buffer,
2404 "503 RCPT TO:<recipient> must precede DATA");
2407 done = 3; /* DATA successfully achieved */
2408 message_ended = END_NOTENDED; /* Indicate in middle of message */
2413 /* The VRFY, EXPN, HELP, ETRN, and NOOP commands are ignored. */
2420 bsmtp_transaction_linecount = receive_linecount;
2425 f.smtp_in_quit = TRUE;
2432 /* The function moan_smtp_batch() does not return. */
2433 moan_smtp_batch(smtp_cmd_buffer, "501 Unexpected argument data");
2438 /* The function moan_smtp_batch() does not return. */
2439 moan_smtp_batch(smtp_cmd_buffer, "501 Unexpected NULL in SMTP command");
2444 /* The function moan_smtp_batch() does not return. */
2445 moan_smtp_batch(smtp_cmd_buffer, "500 Command unrecognized");
2450 return done - 2; /* Convert yield values */
2458 smtp_log_tls_fail(const uschar * errstr)
2460 const uschar * conn_info = smtp_get_connection_info();
2462 if (Ustrncmp(conn_info, US"SMTP ", 5) == 0) conn_info += 5;
2463 /* I'd like to get separated H= here, but too hard for now */
2465 log_write(0, LOG_MAIN, "TLS error on %s %s", conn_info, errstr);
2479 socklen_t len = sizeof(is_fastopen);
2481 /* The tinfo TCPOPT_FAST_OPEN bit seems unreliable, and we don't see state
2482 TCP_SYN_RCV (as of 12.1) so no idea about data-use. */
2484 if (getsockopt(fileno(smtp_out), IPPROTO_TCP, TCP_FASTOPEN, &is_fastopen, &len) == 0)
2489 debug_printf("TFO mode connection (TCP_FASTOPEN getsockopt)\n");
2490 f.tcp_in_fastopen = TRUE;
2493 else DEBUG(D_receive)
2494 debug_printf("TCP_INFO getsockopt: %s\n", strerror(errno));
2496 # elif defined(TCP_INFO)
2497 struct tcp_info tinfo;
2498 socklen_t len = sizeof(tinfo);
2500 if (getsockopt(fileno(smtp_out), IPPROTO_TCP, TCP_INFO, &tinfo, &len) == 0)
2501 # ifdef TCPI_OPT_SYN_DATA /* FreeBSD 11,12 do not seem to have this yet */
2502 if (tinfo.tcpi_options & TCPI_OPT_SYN_DATA)
2505 debug_printf("TFO mode connection (ACKd data-on-SYN)\n");
2506 f.tcp_in_fastopen_data = f.tcp_in_fastopen = TRUE;
2510 if (tinfo.tcpi_state == TCP_SYN_RECV) /* Not seen on FreeBSD 12.1 */
2513 debug_printf("TFO mode connection (state TCP_SYN_RECV)\n");
2514 f.tcp_in_fastopen = TRUE;
2516 else DEBUG(D_receive)
2517 debug_printf("TCP_INFO getsockopt: %s\n", strerror(errno));
2524 log_connect_tls_drop(const uschar * what, const uschar * log_msg)
2526 gstring * g = s_tlslog(NULL);
2527 uschar * tls = string_from_gstring(g);
2529 log_write(L_connection_reject,
2530 log_reject_target, "%s%s%s dropped by %s%s%s",
2531 LOGGING(dnssec) && sender_host_dnssec ? US" DS" : US"",
2532 host_and_ident(TRUE),
2535 log_msg ? US": " : US"", log_msg);
2539 /*************************************************
2540 * Start an SMTP session *
2541 *************************************************/
2543 /* This function is called at the start of an SMTP session. Thereafter,
2544 smtp_setup_msg() is called to initiate each separate message. This
2545 function does host-specific testing, and outputs the banner line.
2548 Returns: FALSE if the session can not continue; something has
2549 gone wrong, or the connection to the host is blocked
2553 smtp_start_session(void)
2556 uschar *user_msg, *log_msg;
2561 gettimeofday(&smtp_connection_start, NULL);
2562 for (smtp_ch_index = 0; smtp_ch_index < SMTP_HBUFF_SIZE; smtp_ch_index++)
2563 smtp_connection_had[smtp_ch_index] = SCH_NONE;
2566 /* Default values for certain variables */
2568 fl.helo_seen = fl.esmtp = fl.helo_accept_junk = FALSE;
2569 smtp_mailcmd_count = 0;
2570 count_nonmail = TRUE_UNSET;
2571 synprot_error_count = unknown_command_count = nonmail_command_count = 0;
2572 smtp_delay_mail = smtp_rlm_base;
2573 fl.auth_advertised = FALSE;
2574 f.smtp_in_pipelining_advertised = f.smtp_in_pipelining_used = FALSE;
2575 f.pipelining_enable = TRUE;
2576 sync_cmd_limit = NON_SYNC_CMD_NON_PIPELINING;
2577 fl.smtp_exit_function_called = FALSE; /* For avoiding loop in not-quit exit */
2579 /* If receiving by -bs from a trusted user, or testing with -bh, we allow
2580 authentication settings from -oMaa to remain in force. */
2582 if (!host_checking && !f.sender_host_notsocket)
2583 sender_host_auth_pubname = sender_host_authenticated = NULL;
2584 authenticated_by = NULL;
2587 tls_in.ver = tls_in.cipher = tls_in.peerdn = NULL;
2588 tls_in.ourcert = tls_in.peercert = NULL;
2590 tls_in.ocsp = OCSP_NOT_REQ;
2591 fl.tls_advertised = FALSE;
2593 fl.dsn_advertised = FALSE;
2595 fl.smtputf8_advertised = FALSE;
2598 /* Reset ACL connection variables */
2602 /* Allow for trailing 0 in the command and data buffers. Tainted. */
2604 smtp_cmd_buffer = store_get_perm(2*SMTP_CMD_BUFFER_SIZE + 2, GET_TAINTED);
2606 smtp_cmd_buffer[0] = 0;
2607 smtp_data_buffer = smtp_cmd_buffer + SMTP_CMD_BUFFER_SIZE + 1;
2609 /* For batched input, the protocol setting can be overridden from the
2610 command line by a trusted caller. */
2612 if (smtp_batched_input)
2614 if (!received_protocol) received_protocol = US"local-bsmtp";
2617 /* For non-batched SMTP input, the protocol setting is forced here. It will be
2618 reset later if any of EHLO/AUTH/STARTTLS are received. */
2622 (sender_host_address ? protocols : protocols_local) [pnormal];
2624 /* Set up the buffer for inputting using direct read() calls, and arrange to
2625 call the local functions instead of the standard C ones. */
2629 receive_getc = smtp_getc;
2630 receive_getbuf = smtp_getbuf;
2631 receive_get_cache = smtp_get_cache;
2632 receive_hasc = smtp_hasc;
2633 receive_ungetc = smtp_ungetc;
2634 receive_feof = smtp_feof;
2635 receive_ferror = smtp_ferror;
2636 lwr_receive_getc = NULL;
2637 lwr_receive_getbuf = NULL;
2638 lwr_receive_hasc = NULL;
2639 lwr_receive_ungetc = NULL;
2641 /* Set up the message size limit; this may be host-specific */
2643 thismessage_size_limit = expand_string_integer(message_size_limit, TRUE);
2644 if (expand_string_message)
2646 if (thismessage_size_limit == -1)
2647 log_write(0, LOG_MAIN|LOG_PANIC, "unable to expand message_size_limit: "
2648 "%s", expand_string_message);
2650 log_write(0, LOG_MAIN|LOG_PANIC, "invalid message_size_limit: "
2651 "%s", expand_string_message);
2652 smtp_closedown(US"Temporary local problem - please try later");
2656 /* When a message is input locally via the -bs or -bS options, sender_host_
2657 unknown is set unless -oMa was used to force an IP address, in which case it
2658 is checked like a real remote connection. When -bs is used from inetd, this
2659 flag is not set, causing the sending host to be checked. The code that deals
2660 with IP source routing (if configured) is never required for -bs or -bS and
2661 the flag sender_host_notsocket is used to suppress it.
2663 If smtp_accept_max and smtp_accept_reserve are set, keep some connections in
2664 reserve for certain hosts and/or networks. */
2666 if (!f.sender_host_unknown)
2669 BOOL reserved_host = FALSE;
2671 /* Look up IP options (source routing info) on the socket if this is not an
2672 -oMa "host", and if any are found, log them and drop the connection.
2674 Linux (and others now, see below) is different to everyone else, so there
2675 has to be some conditional compilation here. Versions of Linux before 2.1.15
2676 used a structure whose name was "options". Somebody finally realized that
2677 this name was silly, and it got changed to "ip_options". I use the
2678 newer name here, but there is a fudge in the script that sets up os.h
2679 to define a macro in older Linux systems.
2681 Sigh. Linux is a fast-moving target. Another generation of Linux uses
2682 glibc 2, which has chosen ip_opts for the structure name. This is now
2683 really a glibc thing rather than a Linux thing, so the condition name
2684 has been changed to reflect this. It is relevant also to GNU/Hurd.
2686 Mac OS 10.x (Darwin) is like the later glibc versions, but without the
2687 setting of the __GLIBC__ macro, so we can't detect it automatically. There's
2688 a special macro defined in the os.h file.
2690 Some DGUX versions on older hardware appear not to support IP options at
2691 all, so there is now a general macro which can be set to cut out this
2694 How to do this properly in IPv6 is not yet known. */
2696 #if !HAVE_IPV6 && !defined(NO_IP_OPTIONS)
2698 # ifdef GLIBC_IP_OPTIONS
2699 # if (!defined __GLIBC__) || (__GLIBC__ < 2)
2704 # elif defined DARWIN_IP_OPTIONS
2710 if (!host_checking && !f.sender_host_notsocket)
2713 EXIM_SOCKLEN_T optlen = sizeof(struct ip_options) + MAX_IPOPTLEN;
2714 struct ip_options *ipopt = store_get(optlen, GET_UNTAINTED);
2715 # elif OPTSTYLE == 2
2716 struct ip_opts ipoptblock;
2717 struct ip_opts *ipopt = &ipoptblock;
2718 EXIM_SOCKLEN_T optlen = sizeof(ipoptblock);
2720 struct ipoption ipoptblock;
2721 struct ipoption *ipopt = &ipoptblock;
2722 EXIM_SOCKLEN_T optlen = sizeof(ipoptblock);
2725 /* Occasional genuine failures of getsockopt() have been seen - for
2726 example, "reset by peer". Therefore, just log and give up on this
2727 call, unless the error is ENOPROTOOPT. This error is given by systems
2728 that have the interfaces but not the mechanism - e.g. GNU/Hurd at the time
2729 of writing. So for that error, carry on - we just can't do an IP options
2732 DEBUG(D_receive) debug_printf("checking for IP options\n");
2734 if (getsockopt(fileno(smtp_out), IPPROTO_IP, IP_OPTIONS, US (ipopt),
2737 if (errno != ENOPROTOOPT)
2739 log_write(0, LOG_MAIN, "getsockopt() failed from %s: %s",
2740 host_and_ident(FALSE), strerror(errno));
2741 smtp_printf("451 SMTP service not available\r\n", FALSE);
2746 /* Deal with any IP options that are set. On the systems I have looked at,
2747 the value of MAX_IPOPTLEN has been 40, meaning that there should never be
2748 more logging data than will fit in big_buffer. Nevertheless, after somebody
2749 questioned this code, I've added in some paranoid checking. */
2751 else if (optlen > 0)
2753 uschar * p = big_buffer;
2754 uschar * pend = big_buffer + big_buffer_size;
2757 struct in_addr addr;
2760 uschar * optstart = US (ipopt->__data);
2761 # elif OPTSTYLE == 2
2762 uschar * optstart = US (ipopt->ip_opts);
2764 uschar * optstart = US (ipopt->ipopt_list);
2767 DEBUG(D_receive) debug_printf("IP options exist\n");
2769 Ustrcpy(p, "IP options on incoming call:");
2772 for (uschar * opt = optstart; opt && opt < US (ipopt) + optlen; )
2787 string_format(p, pend-p, " %s [@%s",
2788 (*opt == IPOPT_SSRR)? "SSRR" : "LSRR",
2789 inet_ntoa(*((struct in_addr *)(&(ipopt->faddr)))))
2790 # elif OPTSTYLE == 2
2791 string_format(p, pend-p, " %s [@%s",
2792 (*opt == IPOPT_SSRR)? "SSRR" : "LSRR",
2793 inet_ntoa(ipopt->ip_dst))
2795 string_format(p, pend-p, " %s [@%s",
2796 (*opt == IPOPT_SSRR)? "SSRR" : "LSRR",
2797 inet_ntoa(ipopt->ipopt_dst))
2806 optcount = (opt[1] - 3) / sizeof(struct in_addr);
2808 while (optcount-- > 0)
2810 memcpy(&addr, adptr, sizeof(addr));
2811 if (!string_format(p, pend - p - 1, "%s%s",
2812 (optcount == 0)? ":" : "@", inet_ntoa(addr)))
2818 adptr += sizeof(struct in_addr);
2826 if (pend - p < 4 + 3*opt[1]) { opt = NULL; break; }
2829 for (int i = 0; i < opt[1]; i++)
2830 p += sprintf(CS p, "%2.2x ", opt[i]);
2838 log_write(0, LOG_MAIN, "%s", big_buffer);
2840 /* Refuse any call with IP options. This is what tcpwrappers 7.5 does. */
2842 log_write(0, LOG_MAIN|LOG_REJECT,
2843 "connection from %s refused (IP options)", host_and_ident(FALSE));
2845 smtp_printf("554 SMTP service not available\r\n", FALSE);
2849 /* Length of options = 0 => there are no options */
2851 else DEBUG(D_receive) debug_printf("no IP options found\n");
2853 #endif /* HAVE_IPV6 && !defined(NO_IP_OPTIONS) */
2855 /* Set keep-alive in socket options. The option is on by default. This
2856 setting is an attempt to get rid of some hanging connections that stick in
2857 read() when the remote end (usually a dialup) goes away. */
2859 if (smtp_accept_keepalive && !f.sender_host_notsocket)
2860 ip_keepalive(fileno(smtp_out), sender_host_address, FALSE);
2862 /* If the current host matches host_lookup, set the name by doing a
2863 reverse lookup. On failure, sender_host_name will be NULL and
2864 host_lookup_failed will be TRUE. This may or may not be serious - optional
2867 if (verify_check_host(&host_lookup) == OK)
2869 (void)host_name_lookup();
2870 host_build_sender_fullhost();
2873 /* Delay this until we have the full name, if it is looked up. */
2875 set_process_info("handling incoming connection from %s",
2876 host_and_ident(FALSE));
2878 /* Expand smtp_receive_timeout, if needed */
2880 if (smtp_receive_timeout_s)
2883 if ( !(exp = expand_string(smtp_receive_timeout_s))
2885 || (smtp_receive_timeout = readconf_readtime(exp, 0, FALSE)) < 0
2887 log_write(0, LOG_MAIN|LOG_PANIC,
2888 "bad value for smtp_receive_timeout: '%s'", exp ? exp : US"");
2891 /* Test for explicit connection rejection */
2893 if (verify_check_host(&host_reject_connection) == OK)
2895 log_write(L_connection_reject, LOG_MAIN|LOG_REJECT, "refused connection "
2896 "from %s (host_reject_connection)", host_and_ident(FALSE));
2898 if (!tls_in.on_connect)
2900 smtp_printf("554 SMTP service not available\r\n", FALSE);
2904 /* Test with TCP Wrappers if so configured. There is a problem in that
2905 hosts_ctl() returns 0 (deny) under a number of system failure circumstances,
2906 such as disks dying. In these cases, it is desirable to reject with a 4xx
2907 error instead of a 5xx error. There isn't a "right" way to detect such
2908 problems. The following kludge is used: errno is zeroed before calling
2909 hosts_ctl(). If the result is "reject", a 5xx error is given only if the
2910 value of errno is 0 or ENOENT (which happens if /etc/hosts.{allow,deny} does
2913 #ifdef USE_TCP_WRAPPERS
2915 if (!(tcp_wrappers_name = expand_string(tcp_wrappers_daemon_name)))
2916 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "Expansion of \"%s\" "
2917 "(tcp_wrappers_name) failed: %s", string_printing(tcp_wrappers_name),
2918 expand_string_message);
2920 if (!hosts_ctl(tcp_wrappers_name,
2921 sender_host_name ? CS sender_host_name : STRING_UNKNOWN,
2922 sender_host_address ? CS sender_host_address : STRING_UNKNOWN,
2923 sender_ident ? CS sender_ident : STRING_UNKNOWN))
2925 if (errno == 0 || errno == ENOENT)
2927 HDEBUG(D_receive) debug_printf("tcp wrappers rejection\n");
2928 log_write(L_connection_reject,
2929 LOG_MAIN|LOG_REJECT, "refused connection from %s "
2930 "(tcp wrappers)", host_and_ident(FALSE));
2931 smtp_printf("554 SMTP service not available\r\n", FALSE);
2935 int save_errno = errno;
2936 HDEBUG(D_receive) debug_printf("tcp wrappers rejected with unexpected "
2937 "errno value %d\n", save_errno);
2938 log_write(L_connection_reject,
2939 LOG_MAIN|LOG_REJECT, "temporarily refused connection from %s "
2940 "(tcp wrappers errno=%d)", host_and_ident(FALSE), save_errno);
2941 smtp_printf("451 Temporary local problem - please try later\r\n", FALSE);
2947 /* Check for reserved slots. The value of smtp_accept_count has already been
2948 incremented to include this process. */
2950 if (smtp_accept_max > 0 &&
2951 smtp_accept_count > smtp_accept_max - smtp_accept_reserve)
2953 if ((rc = verify_check_host(&smtp_reserve_hosts)) != OK)
2955 log_write(L_connection_reject,
2956 LOG_MAIN, "temporarily refused connection from %s: not in "
2957 "reserve list: connected=%d max=%d reserve=%d%s",
2958 host_and_ident(FALSE), smtp_accept_count - 1, smtp_accept_max,
2959 smtp_accept_reserve, (rc == DEFER)? " (lookup deferred)" : "");
2960 smtp_printf("421 %s: Too many concurrent SMTP connections; "
2961 "please try again later\r\n", FALSE, smtp_active_hostname);
2964 reserved_host = TRUE;
2967 /* If a load level above which only messages from reserved hosts are
2968 accepted is set, check the load. For incoming calls via the daemon, the
2969 check is done in the superior process if there are no reserved hosts, to
2970 save a fork. In all cases, the load average will already be available
2971 in a global variable at this point. */
2973 if (smtp_load_reserve >= 0 &&
2974 load_average > smtp_load_reserve &&
2976 verify_check_host(&smtp_reserve_hosts) != OK)
2978 log_write(L_connection_reject,
2979 LOG_MAIN, "temporarily refused connection from %s: not in "
2980 "reserve list and load average = %.2f", host_and_ident(FALSE),
2981 (double)load_average/1000.0);
2982 smtp_printf("421 %s: Too much load; please try again later\r\n", FALSE,
2983 smtp_active_hostname);
2987 /* Determine whether unqualified senders or recipients are permitted
2988 for this host. Unfortunately, we have to do this every time, in order to
2989 set the flags so that they can be inspected when considering qualifying
2990 addresses in the headers. For a site that permits no qualification, this
2991 won't take long, however. */
2993 f.allow_unqualified_sender =
2994 verify_check_host(&sender_unqualified_hosts) == OK;
2996 f.allow_unqualified_recipient =
2997 verify_check_host(&recipient_unqualified_hosts) == OK;
2999 /* Determine whether HELO/EHLO is required for this host. The requirement
3000 can be hard or soft. */
3002 fl.helo_verify_required = verify_check_host(&helo_verify_hosts) == OK;
3003 if (!fl.helo_verify_required)
3004 fl.helo_verify = verify_check_host(&helo_try_verify_hosts) == OK;
3006 /* Determine whether this hosts is permitted to send syntactic junk
3007 after a HELO or EHLO command. */
3009 fl.helo_accept_junk = verify_check_host(&helo_accept_junk_hosts) == OK;
3012 /* For batch SMTP input we are now done. */
3014 if (smtp_batched_input) return TRUE;
3016 /* If valid Proxy Protocol source is connecting, set up session.
3017 Failure will not allow any SMTP function other than QUIT. */
3019 #ifdef SUPPORT_PROXY
3020 proxy_session = FALSE;
3021 f.proxy_session_failed = FALSE;
3022 if (check_proxy_protocol_host())
3023 setup_proxy_protocol_host();
3026 /* Run the connect ACL if it exists */
3029 if (acl_smtp_connect)
3032 if ((rc = acl_check(ACL_WHERE_CONNECT, NULL, acl_smtp_connect, &user_msg,
3036 if (tls_in.on_connect)
3037 log_connect_tls_drop(US"'connect' ACL", log_msg);
3040 (void) smtp_handle_acl_fail(ACL_WHERE_CONNECT, rc, user_msg, log_msg);
3045 /* Start up TLS if tls_on_connect is set. This is for supporting the legacy
3046 smtps port for use with older style SSL MTAs. */
3049 if (tls_in.on_connect)
3051 if (tls_server_start(&user_msg) != OK)
3052 return smtp_log_tls_fail(user_msg);
3053 cmd_list[CMD_LIST_TLS_AUTH].is_mail_cmd = TRUE;
3057 /* Output the initial message for a two-way SMTP connection. It may contain
3058 newlines, which then cause a multi-line response to be given. */
3060 code = US"220"; /* Default status code */
3061 esc = US""; /* Default extended status code */
3062 esclen = 0; /* Length of esc */
3068 smtp_message_code(&code, &codelen, &s, NULL, TRUE);
3072 esclen = codelen - 4;
3075 else if (!(s = expand_string(smtp_banner)))
3077 log_write(0, f.expand_string_forcedfail ? LOG_MAIN : LOG_MAIN|LOG_PANIC_DIE,
3078 "Expansion of \"%s\" (smtp_banner) failed: %s",
3079 smtp_banner, expand_string_message);
3080 /* for force-fail */
3082 if (tls_in.on_connect) tls_close(NULL, TLS_SHUTDOWN_WAIT);
3087 /* Remove any terminating newlines; might as well remove trailing space too */
3090 while (p > s && isspace(p[-1])) p--;
3091 s = string_copyn(s, p-s);
3093 /* It seems that CC:Mail is braindead, and assumes that the greeting message
3094 is all contained in a single IP packet. The original code wrote out the
3095 greeting using several calls to fprint/fputc, and on busy servers this could
3096 cause it to be split over more than one packet - which caused CC:Mail to fall
3097 over when it got the second part of the greeting after sending its first
3098 command. Sigh. To try to avoid this, build the complete greeting message
3099 first, and output it in one fell swoop. This gives a better chance of it
3100 ending up as a single packet. */
3102 ss = string_get(256);
3105 do /* At least once, in case we have an empty string */
3108 uschar *linebreak = Ustrchr(p, '\n');
3109 ss = string_catn(ss, code, 3);
3113 ss = string_catn(ss, US" ", 1);
3117 len = linebreak - p;
3118 ss = string_catn(ss, US"-", 1);
3120 ss = string_catn(ss, esc, esclen);
3121 ss = string_catn(ss, p, len);
3122 ss = string_catn(ss, US"\r\n", 2);
3128 /* Before we write the banner, check that there is no input pending, unless
3129 this synchronisation check is disabled. */
3131 #ifndef DISABLE_PIPE_CONNECT
3132 fl.pipe_connect_acceptable =
3133 sender_host_address && verify_check_host(&pipe_connect_advertise_hosts) == OK;
3136 if (fl.pipe_connect_acceptable)
3137 f.smtp_in_early_pipe_used = TRUE;
3143 unsigned n = smtp_inend - smtp_inptr;
3144 if (n > 128) n = 128;
3146 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP protocol "
3147 "synchronization error (input sent without waiting for greeting): "
3148 "rejected connection from %s input=\"%s\"", host_and_ident(TRUE),
3149 string_printing(string_copyn(smtp_inptr, n)));
3150 smtp_printf("554 SMTP synchronization error\r\n", FALSE);
3154 /* Now output the banner */
3155 /*XXX the ehlo-resp code does its own tls/nontls bit. Maybe subroutine that? */
3158 #ifndef DISABLE_PIPE_CONNECT
3159 fl.pipe_connect_acceptable && pipeline_connect_sends(),
3163 string_from_gstring(ss));
3165 /* Attempt to see if we sent the banner before the last ACK of the 3-way
3166 handshake arrived. If so we must have managed a TFO. */
3169 if (sender_host_address && !f.sender_host_notsocket) tfo_in_check();
3179 /*************************************************
3180 * Handle SMTP syntax and protocol errors *
3181 *************************************************/
3183 /* Write to the log for SMTP syntax errors in incoming commands, if configured
3184 to do so. Then transmit the error response. The return value depends on the
3185 number of syntax and protocol errors in this SMTP session.
3188 type error type, given as a log flag bit
3189 code response code; <= 0 means don't send a response
3190 data data to reflect in the response (can be NULL)
3191 errmess the error message
3193 Returns: -1 limit of syntax/protocol errors NOT exceeded
3194 +1 limit of syntax/protocol errors IS exceeded
3196 These values fit in with the values of the "done" variable in the main
3197 processing loop in smtp_setup_msg(). */
3200 synprot_error(int type, int code, uschar *data, uschar *errmess)
3204 log_write(type, LOG_MAIN, "SMTP %s error in \"%s\" %s %s",
3205 type == L_smtp_syntax_error ? "syntax" : "protocol",
3206 string_printing(smtp_cmd_buffer), host_and_ident(TRUE), errmess);
3208 if (++synprot_error_count > smtp_max_synprot_errors)
3211 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
3212 "syntax or protocol errors (last command was \"%s\", %s)",
3213 host_and_ident(FALSE), string_printing(smtp_cmd_buffer),
3214 string_from_gstring(s_connhad_log(NULL))
3220 smtp_printf("%d%c%s%s%s\r\n", FALSE, code, yield == 1 ? '-' : ' ',
3221 data ? data : US"", data ? US": " : US"", errmess);
3223 smtp_printf("%d Too many syntax or protocol errors\r\n", FALSE, code);
3232 /*************************************************
3233 * Send SMTP response, possibly multiline *
3234 *************************************************/
3236 /* There are, it seems, broken clients out there that cannot handle multiline
3237 responses. If no_multiline_responses is TRUE (it can be set from an ACL), we
3238 output nothing for non-final calls, and only the first line for anything else.
3241 code SMTP code, may involve extended status codes
3242 codelen length of smtp code; if > 4 there's an ESC
3243 final FALSE if the last line isn't the final line
3244 msg message text, possibly containing newlines
3250 smtp_respond(uschar* code, int codelen, BOOL final, uschar *msg)
3255 if (!final && f.no_multiline_responses) return;
3260 esclen = codelen - 4;
3263 /* If this is the first output for a (non-batch) RCPT command, see if all RCPTs
3264 have had the same. Note: this code is also present in smtp_printf(). It would
3265 be tidier to have it only in one place, but when it was added, it was easier to
3266 do it that way, so as not to have to mess with the code for the RCPT command,
3267 which sometimes uses smtp_printf() and sometimes smtp_respond(). */
3269 if (fl.rcpt_in_progress)
3271 if (!rcpt_smtp_response)
3272 rcpt_smtp_response = string_copy(msg);
3273 else if (fl.rcpt_smtp_response_same &&
3274 Ustrcmp(rcpt_smtp_response, msg) != 0)
3275 fl.rcpt_smtp_response_same = FALSE;
3276 fl.rcpt_in_progress = FALSE;
3279 /* Now output the message, splitting it up into multiple lines if necessary.
3280 We only handle pipelining these responses as far as nonfinal/final groups,
3281 not the whole MAIL/RCPT/DATA response set. */
3285 uschar *nl = Ustrchr(msg, '\n');
3288 smtp_printf("%.3s%c%.*s%s\r\n", !final, code, final ? ' ':'-', esclen, esc, msg);
3291 else if (nl[1] == 0 || f.no_multiline_responses)
3293 smtp_printf("%.3s%c%.*s%.*s\r\n", !final, code, final ? ' ':'-', esclen, esc,
3294 (int)(nl - msg), msg);
3299 smtp_printf("%.3s-%.*s%.*s\r\n", TRUE, code, esclen, esc, (int)(nl - msg), msg);
3301 Uskip_whitespace(&msg);
3309 /*************************************************
3310 * Parse user SMTP message *
3311 *************************************************/
3313 /* This function allows for user messages overriding the response code details
3314 by providing a suitable response code string at the start of the message
3315 user_msg. Check the message for starting with a response code and optionally an
3316 extended status code. If found, check that the first digit is valid, and if so,
3317 change the code pointer and length to use the replacement. An invalid code
3318 causes a panic log; in this case, if the log messages is the same as the user
3319 message, we must also adjust the value of the log message to show the code that
3320 is actually going to be used (the original one).
3322 This function is global because it is called from receive.c as well as within
3325 Note that the code length returned includes the terminating whitespace
3326 character, which is always included in the regex match.
3329 code SMTP code, may involve extended status codes
3330 codelen length of smtp code; if > 4 there's an ESC
3332 log_msg optional log message, to be adjusted with the new SMTP code
3333 check_valid if true, verify the response code
3339 smtp_message_code(uschar **code, int *codelen, uschar **msg, uschar **log_msg,
3345 if (!msg || !*msg || !regex_match(regex_smtp_code, *msg, -1, &match))
3348 len = Ustrlen(match);
3349 if (check_valid && (*msg)[0] != (*code)[0])
3351 log_write(0, LOG_MAIN|LOG_PANIC, "configured error code starts with "
3352 "incorrect digit (expected %c) in \"%s\"", (*code)[0], *msg);
3353 if (log_msg && *log_msg == *msg)
3354 *log_msg = string_sprintf("%s %s", *code, *log_msg + len);
3359 *codelen = len; /* Includes final space */
3361 *msg += len; /* Chop the code off the message */
3368 /*************************************************
3369 * Handle an ACL failure *
3370 *************************************************/
3372 /* This function is called when acl_check() fails. As well as calls from within
3373 this module, it is called from receive.c for an ACL after DATA. It sorts out
3374 logging the incident, and sends the error response. A message containing
3375 newlines is turned into a multiline SMTP response, but for logging, only the
3378 There's a table of default permanent failure response codes to use in
3379 globals.c, along with the table of names. VFRY is special. Despite RFC1123 it
3380 defaults disabled in Exim. However, discussion in connection with RFC 821bis
3381 (aka RFC 2821) has concluded that the response should be 252 in the disabled
3382 state, because there are broken clients that try VRFY before RCPT. A 5xx
3383 response should be given only when the address is positively known to be
3384 undeliverable. Sigh. We return 252 if there is no VRFY ACL or it provides
3385 no explicit code, but if there is one we let it know best.
3386 Also, for ETRN, 458 is given on refusal, and for AUTH, 503.
3388 From Exim 4.63, it is possible to override the response code details by
3389 providing a suitable response code string at the start of the message provided
3390 in user_msg. The code's first digit is checked for validity.
3393 where where the ACL was called from
3395 user_msg a message that can be included in an SMTP response
3396 log_msg a message for logging
3398 Returns: 0 in most cases
3399 2 if the failure code was FAIL_DROP, in which case the
3400 SMTP connection should be dropped (this value fits with the
3401 "done" variable in smtp_setup_msg() below)
3405 smtp_handle_acl_fail(int where, int rc, uschar *user_msg, uschar *log_msg)
3407 BOOL drop = rc == FAIL_DROP;
3411 uschar *sender_info = US"";
3414 if (drop) rc = FAIL;
3416 /* Set the default SMTP code, and allow a user message to change it. */
3418 smtp_code = rc == FAIL ? acl_wherecodes[where] : US"451";
3419 smtp_message_code(&smtp_code, &codelen, &user_msg, &log_msg,
3420 where != ACL_WHERE_VRFY);
3422 /* We used to have sender_address here; however, there was a bug that was not
3423 updating sender_address after a rewrite during a verify. When this bug was
3424 fixed, sender_address at this point became the rewritten address. I'm not sure
3425 this is what should be logged, so I've changed to logging the unrewritten
3426 address to retain backward compatibility. */
3430 #ifdef WITH_CONTENT_SCAN
3431 case ACL_WHERE_MIME: what = US"during MIME ACL checks"; break;
3433 case ACL_WHERE_PREDATA: what = US"DATA"; break;
3434 case ACL_WHERE_DATA: what = US"after DATA"; break;
3435 #ifndef DISABLE_PRDR
3436 case ACL_WHERE_PRDR: what = US"after DATA PRDR"; break;
3440 uschar * place = smtp_cmd_data ? smtp_cmd_data : US"in \"connect\" ACL";
3443 if (where == ACL_WHERE_AUTH) /* avoid logging auth creds */
3446 for (s = smtp_cmd_data; *s && !isspace(*s); ) s++;
3447 lim = s - smtp_cmd_data; /* atop after method */
3449 what = string_sprintf("%s %.*s", acl_wherenames[where], lim, place);
3454 case ACL_WHERE_RCPT:
3455 case ACL_WHERE_DATA:
3456 #ifdef WITH_CONTENT_SCAN
3457 case ACL_WHERE_MIME:
3459 sender_info = string_sprintf("F=<%s>%s%s%s%s ",
3460 sender_address_unrewritten ? sender_address_unrewritten : sender_address,
3461 sender_host_authenticated ? US" A=" : US"",
3462 sender_host_authenticated ? sender_host_authenticated : US"",
3463 sender_host_authenticated && authenticated_id ? US":" : US"",
3464 sender_host_authenticated && authenticated_id ? authenticated_id : US""
3469 /* If there's been a sender verification failure with a specific message, and
3470 we have not sent a response about it yet, do so now, as a preliminary line for
3471 failures, but not defers. However, always log it for defer, and log it for fail
3472 unless the sender_verify_fail log selector has been turned off. */
3474 if (sender_verified_failed &&
3475 !testflag(sender_verified_failed, af_sverify_told))
3477 BOOL save_rcpt_in_progress = fl.rcpt_in_progress;
3478 fl.rcpt_in_progress = FALSE; /* So as not to treat these as the error */
3480 setflag(sender_verified_failed, af_sverify_told);
3482 if (rc != FAIL || LOGGING(sender_verify_fail))
3483 log_write(0, LOG_MAIN|LOG_REJECT, "%s sender verify %s for <%s>%s",
3484 host_and_ident(TRUE),
3485 ((sender_verified_failed->special_action & 255) == DEFER)? "defer":"fail",
3486 sender_verified_failed->address,
3487 (sender_verified_failed->message == NULL)? US"" :
3488 string_sprintf(": %s", sender_verified_failed->message));
3490 if (rc == FAIL && sender_verified_failed->user_message)
3491 smtp_respond(smtp_code, codelen, FALSE, string_sprintf(
3492 testflag(sender_verified_failed, af_verify_pmfail)?
3493 "Postmaster verification failed while checking <%s>\n%s\n"
3494 "Several RFCs state that you are required to have a postmaster\n"
3495 "mailbox for each mail domain. This host does not accept mail\n"
3496 "from domains whose servers reject the postmaster address."
3498 testflag(sender_verified_failed, af_verify_nsfail)?
3499 "Callback setup failed while verifying <%s>\n%s\n"
3500 "The initial connection, or a HELO or MAIL FROM:<> command was\n"
3501 "rejected. Refusing MAIL FROM:<> does not help fight spam, disregards\n"
3502 "RFC requirements, and stops you from receiving standard bounce\n"
3503 "messages. This host does not accept mail from domains whose servers\n"
3506 "Verification failed for <%s>\n%s",
3507 sender_verified_failed->address,
3508 sender_verified_failed->user_message));
3510 fl.rcpt_in_progress = save_rcpt_in_progress;
3513 /* Sort out text for logging */
3515 log_msg = log_msg ? string_sprintf(": %s", log_msg) : US"";
3516 if ((lognl = Ustrchr(log_msg, '\n'))) *lognl = 0;
3518 /* Send permanent failure response to the command, but the code used isn't
3519 always a 5xx one - see comments at the start of this function. If the original
3520 rc was FAIL_DROP we drop the connection and yield 2. */
3523 smtp_respond(smtp_code, codelen, TRUE,
3524 user_msg ? user_msg : US"Administrative prohibition");
3526 /* Send temporary failure response to the command. Don't give any details,
3527 unless acl_temp_details is set. This is TRUE for a callout defer, a "defer"
3528 verb, and for a header verify when smtp_return_error_details is set.
3530 This conditional logic is all somewhat of a mess because of the odd
3531 interactions between temp_details and return_error_details. One day it should
3532 be re-implemented in a tidier fashion. */
3535 if (f.acl_temp_details && user_msg)
3537 if ( smtp_return_error_details
3538 && sender_verified_failed
3539 && sender_verified_failed->message
3541 smtp_respond(smtp_code, codelen, FALSE, sender_verified_failed->message);
3543 smtp_respond(smtp_code, codelen, TRUE, user_msg);
3546 smtp_respond(smtp_code, codelen, TRUE,
3547 US"Temporary local problem - please try later");
3549 /* Log the incident to the logs that are specified by log_reject_target
3550 (default main, reject). This can be empty to suppress logging of rejections. If
3551 the connection is not forcibly to be dropped, return 0. Otherwise, log why it
3552 is closing if required and return 2. */
3554 if (log_reject_target != 0)
3557 gstring * g = s_tlslog(NULL);
3558 uschar * tls = string_from_gstring(g);
3559 if (!tls) tls = US"";
3561 uschar * tls = US"";
3563 log_write(where == ACL_WHERE_CONNECT ? L_connection_reject : 0,
3564 log_reject_target, "%s%s%s %s%srejected %s%s",
3565 LOGGING(dnssec) && sender_host_dnssec ? US" DS" : US"",
3566 host_and_ident(TRUE),
3569 rc == FAIL ? US"" : US"temporarily ",
3573 if (!drop) return 0;
3575 log_write(L_smtp_connection, LOG_MAIN, "%s closed by DROP in ACL",
3576 smtp_get_connection_info());
3578 /* Run the not-quit ACL, but without any custom messages. This should not be a
3579 problem, because we get here only if some other ACL has issued "drop", and
3580 in that case, *its* custom messages will have been used above. */
3582 smtp_notquit_exit(US"acl-drop", NULL, NULL);
3584 /* An overenthusiastic fail2ban/iptables implimentation has been seen to result
3585 in the TCP conn staying open, and retrying, despite this process exiting. A
3586 malicious client could possibly do the same, tying up server netowrking
3587 resources. Close the socket explicitly to try to avoid that (there's a note in
3588 the Linux socket(7) manpage, SO_LINGER para, to the effect that exim() without
3589 close() results in the socket always lingering). */
3591 (void) poll_one_fd(fileno(smtp_in), POLLIN, 200);
3592 DEBUG(D_any) debug_printf_indent("SMTP(close)>>\n");
3593 (void) fclose(smtp_in);
3594 (void) fclose(smtp_out);
3602 /*************************************************
3603 * Handle SMTP exit when QUIT is not given *
3604 *************************************************/
3606 /* This function provides a logging/statistics hook for when an SMTP connection
3607 is dropped on the floor or the other end goes away. It's a global function
3608 because it's called from receive.c as well as this module. As well as running
3609 the NOTQUIT ACL, if there is one, this function also outputs a final SMTP
3610 response, either with a custom message from the ACL, or using a default. There
3611 is one case, however, when no message is output - after "drop". In that case,
3612 the ACL that obeyed "drop" has already supplied the custom message, and NULL is
3613 passed to this function.
3615 In case things go wrong while processing this function, causing an error that
3616 may re-enter this function, there is a recursion check.
3619 reason What $smtp_notquit_reason will be set to in the ACL;
3620 if NULL, the ACL is not run
3621 code The error code to return as part of the response
3622 defaultrespond The default message if there's no user_msg
3628 smtp_notquit_exit(uschar *reason, uschar *code, uschar *defaultrespond, ...)
3631 uschar *user_msg = NULL;
3632 uschar *log_msg = NULL;
3634 /* Check for recursive call */
3636 if (fl.smtp_exit_function_called)
3638 log_write(0, LOG_PANIC, "smtp_notquit_exit() called more than once (%s)",
3642 fl.smtp_exit_function_called = TRUE;
3644 /* Call the not-QUIT ACL, if there is one, unless no reason is given. */
3646 if (acl_smtp_notquit && reason)
3648 smtp_notquit_reason = reason;
3649 if ((rc = acl_check(ACL_WHERE_NOTQUIT, NULL, acl_smtp_notquit, &user_msg,
3650 &log_msg)) == ERROR)
3651 log_write(0, LOG_MAIN|LOG_PANIC, "ACL for not-QUIT returned ERROR: %s",
3655 /* If the connection was dropped, we certainly are no longer talking TLS */
3656 tls_in.active.sock = -1;
3658 /* Write an SMTP response if we are expected to give one. As the default
3659 responses are all internal, they should be reasonable size. */
3661 if (code && defaultrespond)
3664 smtp_respond(code, 3, TRUE, user_msg);
3670 va_start(ap, defaultrespond);
3671 g = string_vformat(NULL, SVFMT_EXTEND|SVFMT_REBUFFER, CS defaultrespond, ap);
3673 smtp_printf("%s %s\r\n", FALSE, code, string_from_gstring(g));
3682 /*************************************************
3683 * Verify HELO argument *
3684 *************************************************/
3686 /* This function is called if helo_verify_hosts or helo_try_verify_hosts is
3687 matched. It is also called from ACL processing if verify = helo is used and
3688 verification was not previously tried (i.e. helo_try_verify_hosts was not
3689 matched). The result of its processing is to set helo_verified and
3690 helo_verify_failed. These variables should both be FALSE for this function to
3693 Note that EHLO/HELO is legitimately allowed to quote an address literal. Allow
3694 for IPv6 ::ffff: literals.
3697 Returns: TRUE if testing was completed;
3698 FALSE on a temporary failure
3702 smtp_verify_helo(void)
3706 HDEBUG(D_receive) debug_printf("verifying EHLO/HELO argument \"%s\"\n",
3709 if (sender_helo_name == NULL)
3711 HDEBUG(D_receive) debug_printf("no EHLO/HELO command was issued\n");
3714 /* Deal with the case of -bs without an IP address */
3716 else if (sender_host_address == NULL)
3718 HDEBUG(D_receive) debug_printf("no client IP address: assume success\n");
3719 f.helo_verified = TRUE;
3722 /* Deal with the more common case when there is a sending IP address */
3724 else if (sender_helo_name[0] == '[')
3726 f.helo_verified = Ustrncmp(sender_helo_name+1, sender_host_address,
3727 Ustrlen(sender_host_address)) == 0;
3730 if (!f.helo_verified)
3732 if (strncmpic(sender_host_address, US"::ffff:", 7) == 0)
3733 f.helo_verified = Ustrncmp(sender_helo_name + 1,
3734 sender_host_address + 7, Ustrlen(sender_host_address) - 7) == 0;
3739 { if (f.helo_verified) debug_printf("matched host address\n"); }
3742 /* Do a reverse lookup if one hasn't already given a positive or negative
3743 response. If that fails, or the name doesn't match, try checking with a forward
3748 if (sender_host_name == NULL && !host_lookup_failed)
3749 yield = host_name_lookup() != DEFER;
3751 /* If a host name is known, check it and all its aliases. */
3753 if (sender_host_name)
3754 if ((f.helo_verified = strcmpic(sender_host_name, sender_helo_name) == 0))
3756 sender_helo_dnssec = sender_host_dnssec;
3757 HDEBUG(D_receive) debug_printf("matched host name\n");
3761 uschar **aliases = sender_host_aliases;
3763 if ((f.helo_verified = strcmpic(*aliases++, sender_helo_name) == 0))
3765 sender_helo_dnssec = sender_host_dnssec;
3769 HDEBUG(D_receive) if (f.helo_verified)
3770 debug_printf("matched alias %s\n", *(--aliases));
3773 /* Final attempt: try a forward lookup of the helo name */
3775 if (!f.helo_verified)
3779 {.name = sender_helo_name, .address = NULL, .mx = MX_NONE, .next = NULL};
3781 {.request = US"*", .require = US""};
3783 HDEBUG(D_receive) debug_printf("getting IP address for %s\n",
3785 rc = host_find_bydns(&h, NULL, HOST_FIND_BY_A | HOST_FIND_BY_AAAA,
3786 NULL, NULL, NULL, &d, NULL, NULL);
3787 if (rc == HOST_FOUND || rc == HOST_FOUND_LOCAL)
3788 for (host_item * hh = &h; hh; hh = hh->next)
3789 if (Ustrcmp(hh->address, sender_host_address) == 0)
3791 f.helo_verified = TRUE;
3792 if (h.dnssec == DS_YES) sender_helo_dnssec = TRUE;
3794 debug_printf("IP address for %s matches calling address\n"
3795 "Forward DNS security status: %sverified\n",
3796 sender_helo_name, sender_helo_dnssec ? "" : "un");
3802 if (!f.helo_verified) f.helo_verify_failed = TRUE; /* We've tried ... */
3809 /*************************************************
3810 * Send user response message *
3811 *************************************************/
3813 /* This function is passed a default response code and a user message. It calls
3814 smtp_message_code() to check and possibly modify the response code, and then
3815 calls smtp_respond() to transmit the response. I put this into a function
3816 just to avoid a lot of repetition.
3819 code the response code
3820 user_msg the user message
3826 smtp_user_msg(uschar *code, uschar *user_msg)
3829 smtp_message_code(&code, &len, &user_msg, NULL, TRUE);
3830 smtp_respond(code, len, TRUE, user_msg);
3836 smtp_in_auth(auth_instance *au, uschar ** smtp_resp, uschar ** errmsg)
3838 const uschar *set_id = NULL;
3841 /* Set up globals for error messages */
3843 authenticator_name = au->name;
3844 driver_srcfile = au->srcfile;
3845 driver_srcline = au->srcline;
3847 /* Run the checking code, passing the remainder of the command line as
3848 data. Initials the $auth<n> variables as empty. Initialize $0 empty and set
3849 it as the only set numerical variable. The authenticator may set $auth<n>
3850 and also set other numeric variables. The $auth<n> variables are preferred
3851 nowadays; the numerical variables remain for backwards compatibility.
3853 Afterwards, have a go at expanding the set_id string, even if
3854 authentication failed - for bad passwords it can be useful to log the
3855 userid. On success, require set_id to expand and exist, and put it in
3856 authenticated_id. Save this in permanent store, as the working store gets
3857 reset at HELO, RSET, etc. */
3859 for (int i = 0; i < AUTH_VARS; i++) auth_vars[i] = NULL;
3861 expand_nlength[0] = 0; /* $0 contains nothing */
3863 rc = (au->info->servercode)(au, smtp_cmd_data);
3864 if (au->set_id) set_id = expand_string(au->set_id);
3865 expand_nmax = -1; /* Reset numeric variables */
3866 for (int i = 0; i < AUTH_VARS; i++) auth_vars[i] = NULL; /* Reset $auth<n> */
3867 driver_srcfile = authenticator_name = NULL; driver_srcline = 0;
3869 /* The value of authenticated_id is stored in the spool file and printed in
3870 log lines. It must not contain binary zeros or newline characters. In
3871 normal use, it never will, but when playing around or testing, this error
3872 can (did) happen. To guard against this, ensure that the id contains only
3873 printing characters. */
3875 if (set_id) set_id = string_printing(set_id);
3877 /* For the non-OK cases, set up additional logging data if set_id
3881 set_id = set_id && *set_id
3882 ? string_sprintf(" (set_id=%s)", set_id) : US"";
3884 /* Switch on the result */
3889 if (!au->set_id || set_id) /* Complete success */
3891 if (set_id) authenticated_id = string_copy_perm(set_id, TRUE);
3892 sender_host_authenticated = au->name;
3893 sender_host_auth_pubname = au->public_name;
3894 authentication_failed = FALSE;
3895 authenticated_fail_id = NULL; /* Impossible to already be set? */
3898 (sender_host_address ? protocols : protocols_local)
3899 [pextend + pauthed + (tls_in.active.sock >= 0 ? pcrpted:0)];
3900 *smtp_resp = *errmsg = US"235 Authentication succeeded";
3901 authenticated_by = au;
3905 /* Authentication succeeded, but we failed to expand the set_id string.
3906 Treat this as a temporary error. */
3908 auth_defer_msg = expand_string_message;
3912 if (set_id) authenticated_fail_id = string_copy_perm(set_id, TRUE);
3913 *smtp_resp = string_sprintf("435 Unable to authenticate at present%s",
3914 auth_defer_user_msg);
3915 *errmsg = string_sprintf("435 Unable to authenticate at present%s: %s",
3916 set_id, auth_defer_msg);
3920 *smtp_resp = *errmsg = US"501 Invalid base64 data";
3924 *smtp_resp = *errmsg = US"501 Authentication cancelled";
3928 *smtp_resp = *errmsg = US"553 Initial data not expected";
3932 if (set_id) authenticated_fail_id = string_copy_perm(set_id, TRUE);
3933 *smtp_resp = US"535 Incorrect authentication data";
3934 *errmsg = string_sprintf("535 Incorrect authentication data%s", set_id);
3938 if (set_id) authenticated_fail_id = string_copy_perm(set_id, TRUE);
3939 *smtp_resp = US"435 Internal error";
3940 *errmsg = string_sprintf("435 Internal error%s: return %d from authentication "
3941 "check", set_id, rc);
3953 qualify_recipient(uschar ** recipient, uschar * smtp_cmd_data, uschar * tag)
3956 if (f.allow_unqualified_recipient || strcmpic(*recipient, US"postmaster") == 0)
3958 DEBUG(D_receive) debug_printf("unqualified address %s accepted\n",
3960 rd = Ustrlen(recipient) + 1;
3961 /* deconst ok as *recipient was not const */
3962 *recipient = US rewrite_address_qualify(*recipient, TRUE);
3965 smtp_printf("501 %s: recipient address must contain a domain\r\n", FALSE,
3967 log_write(L_smtp_syntax_error,
3968 LOG_MAIN|LOG_REJECT, "unqualified %s rejected: <%s> %s%s",
3969 tag, *recipient, host_and_ident(TRUE), host_lookup_msg);
3977 smtp_quit_handler(uschar ** user_msgp, uschar ** log_msgp)
3980 f.smtp_in_quit = TRUE;
3981 incomplete_transaction_log(US"QUIT");
3983 && acl_check(ACL_WHERE_QUIT, NULL, acl_smtp_quit, user_msgp, log_msgp)
3985 log_write(0, LOG_MAIN|LOG_PANIC, "ACL for QUIT returned ERROR: %s",
3988 #ifdef EXIM_TCP_CORK
3989 (void) setsockopt(fileno(smtp_out), IPPROTO_TCP, EXIM_TCP_CORK, US &on, sizeof(on));
3993 smtp_respond(US"221", 3, TRUE, *user_msgp);
3995 smtp_printf("221 %s closing connection\r\n", FALSE, smtp_active_hostname);
3997 #ifdef SERVERSIDE_CLOSE_NOWAIT
3998 # ifndef DISABLE_TLS
3999 tls_close(NULL, TLS_SHUTDOWN_NOWAIT);
4002 log_write(L_smtp_connection, LOG_MAIN, "%s closed by QUIT",
4003 smtp_get_connection_info());
4006 # ifndef DISABLE_TLS
4007 tls_close(NULL, TLS_SHUTDOWN_WAIT);
4010 log_write(L_smtp_connection, LOG_MAIN, "%s closed by QUIT",
4011 smtp_get_connection_info());
4013 /* Pause, hoping client will FIN first so that they get the TIME_WAIT.
4014 The socket should become readble (though with no data) */
4016 (void) poll_one_fd(fileno(smtp_in), POLLIN, 200);
4017 #endif /*!SERVERSIDE_CLOSE_NOWAIT*/
4022 smtp_rset_handler(void)
4025 incomplete_transaction_log(US"RSET");
4026 smtp_printf("250 Reset OK\r\n", FALSE);
4027 cmd_list[CMD_LIST_RSET].is_mail_cmd = FALSE;
4028 if (chunking_state > CHUNKING_OFFERED)
4029 chunking_state = CHUNKING_OFFERED;
4034 expand_mailmax(const uschar * s)
4036 if (!(s = expand_cstring(s)))
4037 log_write(0, LOG_MAIN|LOG_PANIC, "failed to expand smtp_accept_max_per_connection");
4038 return *s ? Uatoi(s) : 0;
4041 /*************************************************
4042 * Initialize for SMTP incoming message *
4043 *************************************************/
4045 /* This function conducts the initial dialogue at the start of an incoming SMTP
4046 message, and builds a list of recipients. However, if the incoming message
4047 is part of a batch (-bS option) a separate function is called since it would
4048 be messy having tests splattered about all over this function. This function
4049 therefore handles the case where interaction is occurring. The input and output
4050 files are set up in smtp_in and smtp_out.
4052 The global recipients_list is set to point to a vector of recipient_item
4053 blocks, whose number is given by recipients_count. This is extended by the
4054 receive_add_recipient() function. The global variable sender_address is set to
4055 the sender's address. The yield is +1 if a message has been successfully
4056 started, 0 if a QUIT command was encountered or the connection was refused from
4057 the particular host, or -1 if the connection was lost.
4061 Returns: > 0 message successfully started (reached DATA)
4062 = 0 QUIT read or end of file reached or call refused
4067 smtp_setup_msg(void)
4070 BOOL toomany = FALSE;
4071 BOOL discarded = FALSE;
4072 BOOL last_was_rej_mail = FALSE;
4073 BOOL last_was_rcpt = FALSE;
4074 rmark reset_point = store_mark();
4076 DEBUG(D_receive) debug_printf("smtp_setup_msg entered\n");
4078 /* Reset for start of new message. We allow one RSET not to be counted as a
4079 nonmail command, for those MTAs that insist on sending it between every
4080 message. Ditto for EHLO/HELO and for STARTTLS, to allow for going in and out of
4081 TLS between messages (an Exim client may do this if it has messages queued up
4082 for the host). Note: we do NOT reset AUTH at this point. */
4084 reset_point = smtp_reset(reset_point);
4085 message_ended = END_NOTSTARTED;
4087 chunking_state = f.chunking_offered ? CHUNKING_OFFERED : CHUNKING_NOT_OFFERED;
4089 cmd_list[CMD_LIST_RSET].is_mail_cmd = TRUE;
4090 cmd_list[CMD_LIST_HELO].is_mail_cmd = TRUE;
4091 cmd_list[CMD_LIST_EHLO].is_mail_cmd = TRUE;
4093 cmd_list[CMD_LIST_STARTTLS].is_mail_cmd = TRUE;
4096 if (lwr_receive_getc != NULL)
4098 /* This should have already happened, but if we've gotten confused,
4099 force a reset here. */
4100 DEBUG(D_receive) debug_printf("WARNING: smtp_setup_msg had to restore receive functions to lowers\n");
4101 bdat_pop_receive_functions();
4104 /* Set the local signal handler for SIGTERM - it tries to end off tidily */
4106 had_command_sigterm = 0;
4107 os_non_restarting_signal(SIGTERM, command_sigterm_handler);
4109 /* Batched SMTP is handled in a different function. */
4111 if (smtp_batched_input) return smtp_setup_batch_msg();
4114 if (smtp_in) /* Avoid pure-ACKs while in cmd pingpong phase */
4115 (void) setsockopt(fileno(smtp_in), IPPROTO_TCP, TCP_QUICKACK,
4116 US &off, sizeof(off));
4119 /* Deal with SMTP commands. This loop is exited by setting done to a POSITIVE
4120 value. The values are 2 larger than the required yield of the function. */
4124 const uschar **argv;
4125 uschar *etrn_command;
4126 uschar *etrn_serialize_key;
4128 uschar *log_msg, *smtp_code;
4129 uschar *user_msg = NULL;
4130 uschar *recipient = NULL;
4131 uschar *hello = NULL;
4133 BOOL was_rej_mail = FALSE;
4134 BOOL was_rcpt = FALSE;
4135 void (*oldsignal)(int);
4137 int start, end, sender_domain, recipient_domain;
4140 uschar *orcpt = NULL;
4145 /* Check once per STARTTLS or SSL-on-connect for a TLS AUTH */
4146 if ( tls_in.active.sock >= 0
4148 && tls_in.certificate_verified
4149 && cmd_list[CMD_LIST_TLS_AUTH].is_mail_cmd
4152 cmd_list[CMD_LIST_TLS_AUTH].is_mail_cmd = FALSE;
4154 for (auth_instance * au = auths; au; au = au->next)
4155 if (strcmpic(US"tls", au->driver_name) == 0)
4158 && (rc = acl_check(ACL_WHERE_AUTH, NULL, acl_smtp_auth,
4159 &user_msg, &log_msg)) != OK
4161 done = smtp_handle_acl_fail(ACL_WHERE_AUTH, rc, user_msg, log_msg);
4164 smtp_cmd_data = NULL;
4166 if (smtp_in_auth(au, &s, &ss) == OK)
4167 { DEBUG(D_auth) debug_printf("tls auth succeeded\n"); }
4170 DEBUG(D_auth) debug_printf("tls auth not succeeded\n");
4171 #ifndef DISABLE_EVENT
4173 uschar * save_name = sender_host_authenticated, * logmsg;
4174 sender_host_authenticated = au->name;
4175 if ((logmsg = event_raise(event_action, US"auth:fail", s, NULL)))
4176 log_write(0, LOG_MAIN, "%s", logmsg);
4177 sender_host_authenticated = save_name;
4187 switch(smtp_read_command(
4188 #ifndef DISABLE_PIPE_CONNECT
4189 !fl.pipe_connect_acceptable,
4193 GETC_BUFFER_UNLIMITED))
4195 /* The AUTH command is not permitted to occur inside a transaction, and may
4196 occur successfully only once per connection. Actually, that isn't quite
4197 true. When TLS is started, all previous information about a connection must
4198 be discarded, so a new AUTH is permitted at that time.
4200 AUTH may only be used when it has been advertised. However, it seems that
4201 there are clients that send AUTH when it hasn't been advertised, some of
4202 them even doing this after HELO. And there are MTAs that accept this. Sigh.
4203 So there's a get-out that allows this to happen.
4205 AUTH is initially labelled as a "nonmail command" so that one occurrence
4206 doesn't get counted. We change the label here so that multiple failing
4207 AUTHS will eventually hit the nonmail threshold. */
4211 authentication_failed = TRUE;
4212 cmd_list[CMD_LIST_AUTH].is_mail_cmd = FALSE;
4214 if (!fl.auth_advertised && !f.allow_auth_unadvertised)
4216 done = synprot_error(L_smtp_protocol_error, 503, NULL,
4217 US"AUTH command used when not advertised");
4220 if (sender_host_authenticated)
4222 done = synprot_error(L_smtp_protocol_error, 503, NULL,
4223 US"already authenticated");
4228 done = synprot_error(L_smtp_protocol_error, 503, NULL,
4229 US"not permitted in mail transaction");
4236 && (rc = acl_check(ACL_WHERE_AUTH, NULL, acl_smtp_auth,
4237 &user_msg, &log_msg)) != OK
4240 done = smtp_handle_acl_fail(ACL_WHERE_AUTH, rc, user_msg, log_msg);
4244 /* Find the name of the requested authentication mechanism. */
4247 for (; (c = *smtp_cmd_data) && !isspace(c); smtp_cmd_data++)
4248 if (!isalnum(c) && c != '-' && c != '_')
4250 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4251 US"invalid character in authentication mechanism name");
4255 /* If not at the end of the line, we must be at white space. Terminate the
4256 name and move the pointer on to any data that may be present. */
4260 *smtp_cmd_data++ = 0;
4261 while (isspace(*smtp_cmd_data)) smtp_cmd_data++;
4264 /* Search for an authentication mechanism which is configured for use
4265 as a server and which has been advertised (unless, sigh, allow_auth_
4266 unadvertised is set). */
4270 uschar * smtp_resp, * errmsg;
4272 for (au = auths; au; au = au->next)
4273 if (strcmpic(s, au->public_name) == 0 && au->server &&
4274 (au->advertised || f.allow_auth_unadvertised))
4279 int rc = smtp_in_auth(au, &smtp_resp, &errmsg);
4281 smtp_printf("%s\r\n", FALSE, smtp_resp);
4284 uschar * logmsg = NULL;
4285 #ifndef DISABLE_EVENT
4286 {uschar * save_name = sender_host_authenticated;
4287 sender_host_authenticated = au->name;
4288 logmsg = event_raise(event_action, US"auth:fail", smtp_resp, NULL);
4289 sender_host_authenticated = save_name;
4293 log_write(0, LOG_MAIN|LOG_REJECT, "%s", logmsg);
4295 log_write(0, LOG_MAIN|LOG_REJECT, "%s authenticator failed for %s: %s",
4296 au->name, host_and_ident(FALSE), errmsg);
4300 done = synprot_error(L_smtp_protocol_error, 504, NULL,
4301 string_sprintf("%s authentication mechanism not supported", s));
4304 break; /* AUTH_CMD */
4306 /* The HELO/EHLO commands are permitted to appear in the middle of a
4307 session as well as at the beginning. They have the effect of a reset in
4308 addition to their other functions. Their absence at the start cannot be
4309 taken to be an error.
4313 If the EHLO command is not acceptable to the SMTP server, 501, 500,
4314 or 502 failure replies MUST be returned as appropriate. The SMTP
4315 server MUST stay in the same state after transmitting these replies
4316 that it was in before the EHLO was received.
4318 Therefore, we do not do the reset until after checking the command for
4319 acceptability. This change was made for Exim release 4.11. Previously
4320 it did the reset first. */
4333 HELO_EHLO: /* Common code for HELO and EHLO */
4334 cmd_list[CMD_LIST_HELO].is_mail_cmd = FALSE;
4335 cmd_list[CMD_LIST_EHLO].is_mail_cmd = FALSE;
4337 /* Reject the HELO if its argument was invalid or non-existent. A
4338 successful check causes the argument to be saved in malloc store. */
4340 if (!check_helo(smtp_cmd_data))
4342 smtp_printf("501 Syntactically invalid %s argument(s)\r\n", FALSE, hello);
4344 log_write(0, LOG_MAIN|LOG_REJECT, "rejected %s from %s: syntactically "
4345 "invalid argument(s): %s", hello, host_and_ident(FALSE),
4346 *smtp_cmd_argument == 0 ? US"(no argument given)" :
4347 string_printing(smtp_cmd_argument));
4349 if (++synprot_error_count > smtp_max_synprot_errors)
4351 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
4352 "syntax or protocol errors (last command was \"%s\", %s)",
4353 host_and_ident(FALSE), string_printing(smtp_cmd_buffer),
4354 string_from_gstring(s_connhad_log(NULL))
4362 /* If sender_host_unknown is true, we have got here via the -bs interface,
4363 not called from inetd. Otherwise, we are running an IP connection and the
4364 host address will be set. If the helo name is the primary name of this
4365 host and we haven't done a reverse lookup, force one now. If helo_verify_required
4366 is set, ensure that the HELO name matches the actual host. If helo_verify
4367 is set, do the same check, but softly. */
4369 if (!f.sender_host_unknown)
4371 BOOL old_helo_verified = f.helo_verified;
4372 uschar *p = smtp_cmd_data;
4374 while (*p != 0 && !isspace(*p)) { *p = tolower(*p); p++; }
4377 /* Force a reverse lookup if HELO quoted something in helo_lookup_domains
4378 because otherwise the log can be confusing. */
4380 if ( !sender_host_name
4381 && match_isinlist(sender_helo_name, CUSS &helo_lookup_domains, 0,
4382 &domainlist_anchor, NULL, MCL_DOMAIN, TRUE, NULL) == OK)
4383 (void)host_name_lookup();
4385 /* Rebuild the fullhost info to include the HELO name (and the real name
4386 if it was looked up.) */
4388 host_build_sender_fullhost(); /* Rebuild */
4389 set_process_info("handling%s incoming connection from %s",
4390 tls_in.active.sock >= 0 ? " TLS" : "", host_and_ident(FALSE));
4392 /* Verify if configured. This doesn't give much security, but it does
4393 make some people happy to be able to do it. If helo_verify_required is set,
4394 (host matches helo_verify_hosts) failure forces rejection. If helo_verify
4395 is set (host matches helo_try_verify_hosts), it does not. This is perhaps
4396 now obsolescent, since the verification can now be requested selectively
4399 f.helo_verified = f.helo_verify_failed = sender_helo_dnssec = FALSE;
4400 if (fl.helo_verify_required || fl.helo_verify)
4402 BOOL tempfail = !smtp_verify_helo();
4403 if (!f.helo_verified)
4405 if (fl.helo_verify_required)
4407 smtp_printf("%d %s argument does not match calling host\r\n", FALSE,
4408 tempfail? 451 : 550, hello);
4409 log_write(0, LOG_MAIN|LOG_REJECT, "%srejected \"%s %s\" from %s",
4410 tempfail? "temporarily " : "",
4411 hello, sender_helo_name, host_and_ident(FALSE));
4412 f.helo_verified = old_helo_verified;
4413 break; /* End of HELO/EHLO processing */
4415 HDEBUG(D_all) debug_printf("%s verification failed but host is in "
4416 "helo_try_verify_hosts\n", hello);
4422 /* set up SPF context */
4423 spf_conn_init(sender_helo_name, sender_host_address);
4426 /* Apply an ACL check if one is defined; afterwards, recheck
4427 synchronization in case the client started sending in a delay. */
4430 if ((rc = acl_check(ACL_WHERE_HELO, NULL, acl_smtp_helo,
4431 &user_msg, &log_msg)) != OK)
4433 done = smtp_handle_acl_fail(ACL_WHERE_HELO, rc, user_msg, log_msg);
4434 sender_helo_name = NULL;
4435 host_build_sender_fullhost(); /* Rebuild */
4438 #ifndef DISABLE_PIPE_CONNECT
4439 else if (!fl.pipe_connect_acceptable && !check_sync())
4441 else if (!check_sync())
4445 /* Generate an OK reply. The default string includes the ident if present,
4446 and also the IP address if present. Reflecting back the ident is intended
4447 as a deterrent to mail forgers. For maximum efficiency, and also because
4448 some broken systems expect each response to be in a single packet, arrange
4449 that the entire reply is sent in one write(). */
4451 fl.auth_advertised = FALSE;
4452 f.smtp_in_pipelining_advertised = FALSE;
4454 fl.tls_advertised = FALSE;
4456 fl.dsn_advertised = FALSE;
4458 fl.smtputf8_advertised = FALSE;
4461 /* Expand the per-connection message count limit option */
4462 smtp_mailcmd_max = expand_mailmax(smtp_accept_max_per_connection);
4464 smtp_code = US"250 "; /* Default response code plus space*/
4467 /* sender_host_name below will be tainted, so save on copy when we hit it */
4468 g = string_get_tainted(24, GET_TAINTED);
4469 g = string_fmt_append(g, "%.3s %s Hello %s%s%s",
4471 smtp_active_hostname,
4472 sender_ident ? sender_ident : US"",
4473 sender_ident ? US" at " : US"",
4474 sender_host_name ? sender_host_name : sender_helo_name);
4476 if (sender_host_address)
4477 g = string_fmt_append(g, " [%s]", sender_host_address);
4480 /* A user-supplied EHLO greeting may not contain more than one line. Note
4481 that the code returned by smtp_message_code() includes the terminating
4482 whitespace character. */
4488 smtp_message_code(&smtp_code, &codelen, &user_msg, NULL, TRUE);
4489 s = string_sprintf("%.*s%s", codelen, smtp_code, user_msg);
4490 if ((ss = strpbrk(CS s, "\r\n")) != NULL)
4492 log_write(0, LOG_MAIN|LOG_PANIC, "EHLO/HELO response must not contain "
4493 "newlines: message truncated: %s", string_printing(s));
4496 g = string_cat(NULL, s);
4499 g = string_catn(g, US"\r\n", 2);
4501 /* If we received EHLO, we must create a multiline response which includes
4502 the functions supported. */
4508 /* I'm not entirely happy with this, as an MTA is supposed to check
4509 that it has enough room to accept a message of maximum size before
4510 it sends this. However, there seems little point in not sending it.
4511 The actual size check happens later at MAIL FROM time. By postponing it
4512 till then, VRFY and EXPN can be used after EHLO when space is short. */
4514 if (thismessage_size_limit > 0)
4515 g = string_fmt_append(g, "%.3s-SIZE %d\r\n", smtp_code,
4516 thismessage_size_limit);
4519 g = string_catn(g, smtp_code, 3);
4520 g = string_catn(g, US"-SIZE\r\n", 7);
4523 #ifdef EXPERIMENTAL_ESMTP_LIMITS
4524 if ( (smtp_mailcmd_max > 0 || recipients_max)
4525 && verify_check_host(&limits_advertise_hosts) == OK)
4527 g = string_fmt_append(g, "%.3s-LIMITS", smtp_code);
4528 if (smtp_mailcmd_max > 0)
4529 g = string_fmt_append(g, " MAILMAX=%d", smtp_mailcmd_max);
4531 g = string_fmt_append(g, " RCPTMAX=%d", recipients_max);
4532 g = string_catn(g, US"\r\n", 2);
4536 /* Exim does not do protocol conversion or data conversion. It is 8-bit
4537 clean; if it has an 8-bit character in its hand, it just sends it. It
4538 cannot therefore specify 8BITMIME and remain consistent with the RFCs.
4539 However, some users want this option simply in order to stop MUAs
4540 mangling messages that contain top-bit-set characters. It is therefore
4541 provided as an option. */
4543 if (accept_8bitmime)
4545 g = string_catn(g, smtp_code, 3);
4546 g = string_catn(g, US"-8BITMIME\r\n", 11);
4549 /* Advertise DSN support if configured to do so. */
4550 if (verify_check_host(&dsn_advertise_hosts) != FAIL)
4552 g = string_catn(g, smtp_code, 3);
4553 g = string_catn(g, US"-DSN\r\n", 6);
4554 fl.dsn_advertised = TRUE;
4557 /* Advertise ETRN/VRFY/EXPN if there's are ACL checking whether a host is
4558 permitted to issue them; a check is made when any host actually tries. */
4562 g = string_catn(g, smtp_code, 3);
4563 g = string_catn(g, US"-ETRN\r\n", 7);
4567 g = string_catn(g, smtp_code, 3);
4568 g = string_catn(g, US"-VRFY\r\n", 7);
4572 g = string_catn(g, smtp_code, 3);
4573 g = string_catn(g, US"-EXPN\r\n", 7);
4576 /* Exim is quite happy with pipelining, so let the other end know that
4577 it is safe to use it, unless advertising is disabled. */
4579 if ( f.pipelining_enable
4580 && verify_check_host(&pipelining_advertise_hosts) == OK)
4582 g = string_catn(g, smtp_code, 3);
4583 g = string_catn(g, US"-PIPELINING\r\n", 13);
4584 sync_cmd_limit = NON_SYNC_CMD_PIPELINING;
4585 f.smtp_in_pipelining_advertised = TRUE;
4587 #ifndef DISABLE_PIPE_CONNECT
4588 if (fl.pipe_connect_acceptable)
4590 f.smtp_in_early_pipe_advertised = TRUE;
4591 g = string_catn(g, smtp_code, 3);
4592 g = string_catn(g, US"-" EARLY_PIPE_FEATURE_NAME "\r\n", EARLY_PIPE_FEATURE_LEN+3);
4598 /* If any server authentication mechanisms are configured, advertise
4599 them if the current host is in auth_advertise_hosts. The problem with
4600 advertising always is that some clients then require users to
4601 authenticate (and aren't configurable otherwise) even though it may not
4602 be necessary (e.g. if the host is in host_accept_relay).
4604 RFC 2222 states that SASL mechanism names contain only upper case
4605 letters, so output the names in upper case, though we actually recognize
4606 them in either case in the AUTH command. */
4610 && !sender_host_authenticated
4612 && verify_check_host(&auth_advertise_hosts) == OK
4616 for (auth_instance * au = auths; au; au = au->next)
4618 au->advertised = FALSE;
4621 DEBUG(D_auth+D_expand) debug_printf_indent(
4622 "Evaluating advertise_condition for %s %s athenticator\n",
4623 au->name, au->public_name);
4624 if ( !au->advertise_condition
4625 || expand_check_condition(au->advertise_condition, au->name,
4632 g = string_catn(g, smtp_code, 3);
4633 g = string_catn(g, US"-AUTH", 5);
4635 fl.auth_advertised = TRUE;
4638 g = string_catn(g, US" ", 1);
4639 g = string_cat (g, au->public_name);
4640 while (++saveptr < g->ptr) g->s[saveptr] = toupper(g->s[saveptr]);
4641 au->advertised = TRUE;
4646 if (!first) g = string_catn(g, US"\r\n", 2);
4649 /* RFC 3030 CHUNKING */
4651 if (verify_check_host(&chunking_advertise_hosts) != FAIL)
4653 g = string_catn(g, smtp_code, 3);
4654 g = string_catn(g, US"-CHUNKING\r\n", 11);
4655 f.chunking_offered = TRUE;
4656 chunking_state = CHUNKING_OFFERED;
4659 /* Advertise TLS (Transport Level Security) aka SSL (Secure Socket Layer)
4660 if it has been included in the binary, and the host matches
4661 tls_advertise_hosts. We must *not* advertise if we are already in a
4662 secure connection. */
4665 if (tls_in.active.sock < 0 &&
4666 verify_check_host(&tls_advertise_hosts) != FAIL)
4668 g = string_catn(g, smtp_code, 3);
4669 g = string_catn(g, US"-STARTTLS\r\n", 11);
4670 fl.tls_advertised = TRUE;
4674 #ifndef DISABLE_PRDR
4675 /* Per Recipient Data Response, draft by Eric A. Hall extending RFC */
4678 g = string_catn(g, smtp_code, 3);
4679 g = string_catn(g, US"-PRDR\r\n", 7);
4684 if ( accept_8bitmime
4685 && verify_check_host(&smtputf8_advertise_hosts) != FAIL)
4687 g = string_catn(g, smtp_code, 3);
4688 g = string_catn(g, US"-SMTPUTF8\r\n", 11);
4689 fl.smtputf8_advertised = TRUE;
4693 /* Finish off the multiline reply with one that is always available. */
4695 g = string_catn(g, smtp_code, 3);
4696 g = string_catn(g, US" HELP\r\n", 7);
4699 /* Terminate the string (for debug), write it, and note that HELO/EHLO
4703 if (tls_in.active.sock >= 0)
4704 (void)tls_write(NULL, g->s, g->ptr,
4705 # ifndef DISABLE_PIPE_CONNECT
4706 fl.pipe_connect_acceptable && pipeline_connect_sends());
4712 (void) fwrite(g->s, 1, g->ptr, smtp_out);
4714 DEBUG(D_receive) for (const uschar * t, * s = string_from_gstring(g);
4715 s && (t = Ustrchr(s, '\r'));
4716 s = t + 2) /* \r\n */
4717 debug_printf("%s %.*s\n",
4718 s == g->s ? "SMTP>>" : " ",
4720 fl.helo_seen = TRUE;
4722 /* Reset the protocol and the state, abandoning any previous message. */
4724 (sender_host_address ? protocols : protocols_local)
4726 ? pextend + (sender_host_authenticated ? pauthed : 0)
4728 + (tls_in.active.sock >= 0 ? pcrpted : 0)
4730 cancel_cutthrough_connection(TRUE, US"sent EHLO response");
4731 reset_point = smtp_reset(reset_point);
4733 break; /* HELO/EHLO */
4736 /* The MAIL command requires an address as an operand. All we do
4737 here is to parse it for syntactic correctness. The form "<>" is
4738 a special case which converts into an empty string. The start/end
4739 pointers in the original are not used further for this address, as
4740 it is the canonical extracted address which is all that is kept. */
4744 smtp_mailcmd_count++; /* Count for limit and ratelimit */
4746 was_rej_mail = TRUE; /* Reset if accepted */
4747 env_mail_type_t * mail_args; /* Sanity check & validate args */
4750 if ( fl.helo_verify_required
4751 || verify_check_host(&hosts_require_helo) == OK)
4753 smtp_printf("503 HELO or EHLO required\r\n", FALSE);
4754 log_write(0, LOG_MAIN|LOG_REJECT, "rejected MAIL from %s: no "
4755 "HELO/EHLO given", host_and_ident(FALSE));
4758 else if (smtp_mailcmd_max < 0)
4759 smtp_mailcmd_max = expand_mailmax(smtp_accept_max_per_connection);
4763 done = synprot_error(L_smtp_protocol_error, 503, NULL,
4764 US"sender already given");
4768 if (!*smtp_cmd_data)
4770 done = synprot_error(L_smtp_protocol_error, 501, NULL,
4771 US"MAIL must have an address operand");
4775 /* Check to see if the limit for messages per connection would be
4776 exceeded by accepting further messages. */
4778 if (smtp_mailcmd_max > 0 && smtp_mailcmd_count > smtp_mailcmd_max)
4780 smtp_printf("421 too many messages in this connection\r\n", FALSE);
4781 log_write(0, LOG_MAIN|LOG_REJECT, "rejected MAIL command %s: too many "
4782 "messages in one connection", host_and_ident(TRUE));
4786 /* Reset for start of message - even if this is going to fail, we
4787 obviously need to throw away any previous data. */
4789 cancel_cutthrough_connection(TRUE, US"MAIL received");
4790 reset_point = smtp_reset(reset_point);
4792 sender_data = recipient_data = NULL;
4794 /* Loop, checking for ESMTP additions to the MAIL FROM command. */
4796 if (fl.esmtp) for(;;)
4798 uschar *name, *value, *end;
4799 unsigned long int size;
4800 BOOL arg_error = FALSE;
4802 if (!extract_option(&name, &value)) break;
4804 for (mail_args = env_mail_type_list;
4805 mail_args->value != ENV_MAIL_OPT_NULL;
4808 if (strcmpic(name, mail_args->name) == 0)
4810 if (mail_args->need_value && strcmpic(value, US"") == 0)
4813 switch(mail_args->value)
4815 /* Handle SIZE= by reading the value. We don't do the check till later,
4816 in order to be able to log the sender address on failure. */
4817 case ENV_MAIL_OPT_SIZE:
4818 if (((size = Ustrtoul(value, &end, 10)), *end == 0))
4820 if ((size == ULONG_MAX && errno == ERANGE) || size > INT_MAX)
4822 message_size = (int)size;
4828 /* If this session was initiated with EHLO and accept_8bitmime is set,
4829 Exim will have indicated that it supports the BODY=8BITMIME option. In
4830 fact, it does not support this according to the RFCs, in that it does not
4831 take any special action for forwarding messages containing 8-bit
4832 characters. That is why accept_8bitmime is not the default setting, but
4833 some sites want the action that is provided. We recognize both "8BITMIME"
4834 and "7BIT" as body types, but take no action. */
4835 case ENV_MAIL_OPT_BODY:
4836 if (accept_8bitmime) {
4837 if (strcmpic(value, US"8BITMIME") == 0)
4839 else if (strcmpic(value, US"7BIT") == 0)
4844 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4845 US"invalid data for BODY");
4848 DEBUG(D_receive) debug_printf("8BITMIME: %d\n", body_8bitmime);
4854 /* Handle the two DSN options, but only if configured to do so (which
4855 will have caused "DSN" to be given in the EHLO response). The code itself
4856 is included only if configured in at build time. */
4858 case ENV_MAIL_OPT_RET:
4859 if (fl.dsn_advertised)
4861 /* Check if RET has already been set */
4864 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4865 US"RET can be specified once only");
4868 dsn_ret = strcmpic(value, US"HDRS") == 0
4870 : strcmpic(value, US"FULL") == 0
4873 DEBUG(D_receive) debug_printf("DSN_RET: %d\n", dsn_ret);
4874 /* Check for invalid invalid value, and exit with error */
4877 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4878 US"Value for RET is invalid");
4883 case ENV_MAIL_OPT_ENVID:
4884 if (fl.dsn_advertised)
4886 /* Check if the dsn envid has been already set */
4889 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4890 US"ENVID can be specified once only");
4893 dsn_envid = string_copy(value);
4894 DEBUG(D_receive) debug_printf("DSN_ENVID: %s\n", dsn_envid);
4898 /* Handle the AUTH extension. If the value given is not "<>" and either
4899 the ACL says "yes" or there is no ACL but the sending host is
4900 authenticated, we set it up as the authenticated sender. However, if the
4901 authenticator set a condition to be tested, we ignore AUTH on MAIL unless
4902 the condition is met. The value of AUTH is an xtext, which means that +,
4903 = and cntrl chars are coded in hex; however "<>" is unaffected by this
4905 case ENV_MAIL_OPT_AUTH:
4906 if (Ustrcmp(value, "<>") != 0)
4911 if (auth_xtextdecode(value, &authenticated_sender) < 0)
4913 /* Put back terminator overrides for error message */
4916 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4917 US"invalid data for AUTH");
4920 if (!acl_smtp_mailauth)
4922 ignore_msg = US"client not authenticated";
4923 rc = sender_host_authenticated ? OK : FAIL;
4927 ignore_msg = US"rejected by ACL";
4928 rc = acl_check(ACL_WHERE_MAILAUTH, NULL, acl_smtp_mailauth,
4929 &user_msg, &log_msg);
4935 if (authenticated_by == NULL ||
4936 authenticated_by->mail_auth_condition == NULL ||
4937 expand_check_condition(authenticated_by->mail_auth_condition,
4938 authenticated_by->name, US"authenticator"))
4939 break; /* Accept the AUTH */
4941 ignore_msg = US"server_mail_auth_condition failed";
4942 if (authenticated_id != NULL)
4943 ignore_msg = string_sprintf("%s: authenticated ID=\"%s\"",
4944 ignore_msg, authenticated_id);
4949 authenticated_sender = NULL;
4950 log_write(0, LOG_MAIN, "ignoring AUTH=%s from %s (%s)",
4951 value, host_and_ident(TRUE), ignore_msg);
4954 /* Should only get DEFER or ERROR here. Put back terminator
4955 overrides for error message */
4960 (void)smtp_handle_acl_fail(ACL_WHERE_MAILAUTH, rc, user_msg,
4967 #ifndef DISABLE_PRDR
4968 case ENV_MAIL_OPT_PRDR:
4970 prdr_requested = TRUE;
4975 case ENV_MAIL_OPT_UTF8:
4976 if (!fl.smtputf8_advertised)
4978 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4979 US"SMTPUTF8 used when not advertised");
4983 DEBUG(D_receive) debug_printf("smtputf8 requested\n");
4984 message_smtputf8 = allow_utf8_domains = TRUE;
4985 if (Ustrncmp(received_protocol, US"utf8", 4) != 0)
4987 int old_pool = store_pool;
4988 store_pool = POOL_PERM;
4989 received_protocol = string_sprintf("utf8%s", received_protocol);
4990 store_pool = old_pool;
4995 /* No valid option. Stick back the terminator characters and break
4996 the loop. Do the name-terminator second as extract_option sets
4997 value==name when it found no equal-sign.
4998 An error for a malformed address will occur. */
4999 case ENV_MAIL_OPT_NULL:
5007 /* Break out of for loop if switch() had bad argument or
5008 when start of the email address is reached */
5009 if (arg_error) break;
5012 /* If we have passed the threshold for rate limiting, apply the current
5013 delay, and update it for next time, provided this is a limited host. */
5015 if (smtp_mailcmd_count > smtp_rlm_threshold &&
5016 verify_check_host(&smtp_ratelimit_hosts) == OK)
5018 DEBUG(D_receive) debug_printf("rate limit MAIL: delay %.3g sec\n",
5019 smtp_delay_mail/1000.0);
5020 millisleep((int)smtp_delay_mail);
5021 smtp_delay_mail *= smtp_rlm_factor;
5022 if (smtp_delay_mail > (double)smtp_rlm_limit)
5023 smtp_delay_mail = (double)smtp_rlm_limit;
5026 /* Now extract the address, first applying any SMTP-time rewriting. The
5027 TRUE flag allows "<>" as a sender address. */
5029 raw_sender = rewrite_existflags & rewrite_smtp
5030 /* deconst ok as smtp_cmd_data was not const */
5031 ? US rewrite_one(smtp_cmd_data, rewrite_smtp, NULL, FALSE, US"",
5032 global_rewrite_rules)
5036 parse_extract_address(raw_sender, &errmess, &start, &end, &sender_domain,
5041 done = synprot_error(L_smtp_syntax_error, 501, smtp_cmd_data, errmess);
5045 sender_address = raw_sender;
5047 /* If there is a configured size limit for mail, check that this message
5048 doesn't exceed it. The check is postponed to this point so that the sender
5051 if (thismessage_size_limit > 0 && message_size > thismessage_size_limit)
5053 smtp_printf("552 Message size exceeds maximum permitted\r\n", FALSE);
5054 log_write(L_size_reject,
5055 LOG_MAIN|LOG_REJECT, "rejected MAIL FROM:<%s> %s: "
5056 "message too big: size%s=%d max=%d",
5058 host_and_ident(TRUE),
5059 (message_size == INT_MAX)? ">" : "",
5061 thismessage_size_limit);
5062 sender_address = NULL;
5066 /* Check there is enough space on the disk unless configured not to.
5067 When smtp_check_spool_space is set, the check is for thismessage_size_limit
5068 plus the current message - i.e. we accept the message only if it won't
5069 reduce the space below the threshold. Add 5000 to the size to allow for
5070 overheads such as the Received: line and storing of recipients, etc.
5071 By putting the check here, even when SIZE is not given, it allow VRFY
5072 and EXPN etc. to be used when space is short. */
5074 if (!receive_check_fs(
5075 smtp_check_spool_space && message_size >= 0
5076 ? message_size + 5000 : 0))
5078 smtp_printf("452 Space shortage, please try later\r\n", FALSE);
5079 sender_address = NULL;
5083 /* If sender_address is unqualified, reject it, unless this is a locally
5084 generated message, or the sending host or net is permitted to send
5085 unqualified addresses - typically local machines behaving as MUAs -
5086 in which case just qualify the address. The flag is set above at the start
5087 of the SMTP connection. */
5089 if (!sender_domain && *sender_address)
5090 if (f.allow_unqualified_sender)
5092 sender_domain = Ustrlen(sender_address) + 1;
5093 /* deconst ok as sender_address was not const */
5094 sender_address = US rewrite_address_qualify(sender_address, FALSE);
5095 DEBUG(D_receive) debug_printf("unqualified address %s accepted\n",
5100 smtp_printf("501 %s: sender address must contain a domain\r\n", FALSE,
5102 log_write(L_smtp_syntax_error,
5103 LOG_MAIN|LOG_REJECT,
5104 "unqualified sender rejected: <%s> %s%s",
5106 host_and_ident(TRUE),
5108 sender_address = NULL;
5112 /* Apply an ACL check if one is defined, before responding. Afterwards,
5113 when pipelining is not advertised, do another sync check in case the ACL
5114 delayed and the client started sending in the meantime. */
5118 rc = acl_check(ACL_WHERE_MAIL, NULL, acl_smtp_mail, &user_msg, &log_msg);
5119 if (rc == OK && !f.smtp_in_pipelining_advertised && !check_sync())
5125 if (rc == OK || rc == DISCARD)
5127 BOOL more = pipeline_response();
5130 smtp_printf("%s%s%s", more, US"250 OK",
5131 #ifndef DISABLE_PRDR
5132 prdr_requested ? US", PRDR Requested" : US"",
5139 #ifndef DISABLE_PRDR
5141 user_msg = string_sprintf("%s%s", user_msg, US", PRDR Requested");
5143 smtp_user_msg(US"250", user_msg);
5145 smtp_delay_rcpt = smtp_rlr_base;
5146 f.recipients_discarded = (rc == DISCARD);
5147 was_rej_mail = FALSE;
5151 done = smtp_handle_acl_fail(ACL_WHERE_MAIL, rc, user_msg, log_msg);
5152 sender_address = NULL;
5157 /* The RCPT command requires an address as an operand. There may be any
5158 number of RCPT commands, specifying multiple recipients. We build them all
5159 into a data structure. The start/end values given by parse_extract_address
5160 are not used, as we keep only the extracted address. */
5164 /* We got really to many recipients. A check against configured
5165 limits is done later */
5166 if (rcpt_count < 0 || rcpt_count >= INT_MAX/2)
5167 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "Too many recipients: %d", rcpt_count);
5169 was_rcpt = fl.rcpt_in_progress = TRUE;
5171 /* There must be a sender address; if the sender was rejected and
5172 pipelining was advertised, we assume the client was pipelining, and do not
5173 count this as a protocol error. Reset was_rej_mail so that further RCPTs
5174 get the same treatment. */
5176 if (!sender_address)
5178 if (f.smtp_in_pipelining_advertised && last_was_rej_mail)
5180 smtp_printf("503 sender not yet given\r\n", FALSE);
5181 was_rej_mail = TRUE;
5185 done = synprot_error(L_smtp_protocol_error, 503, NULL,
5186 US"sender not yet given");
5187 was_rcpt = FALSE; /* Not a valid RCPT */
5193 /* Check for an operand */
5195 if (!smtp_cmd_data[0])
5197 done = synprot_error(L_smtp_syntax_error, 501, NULL,
5198 US"RCPT must have an address operand");
5203 /* Set the DSN flags orcpt and dsn_flags from the session*/
5207 if (fl.esmtp) for(;;)
5209 uschar *name, *value;
5211 if (!extract_option(&name, &value))
5214 if (fl.dsn_advertised && strcmpic(name, US"ORCPT") == 0)
5216 /* Check whether orcpt has been already set */
5219 done = synprot_error(L_smtp_syntax_error, 501, NULL,
5220 US"ORCPT can be specified once only");
5223 orcpt = string_copy(value);
5224 DEBUG(D_receive) debug_printf("DSN orcpt: %s\n", orcpt);
5227 else if (fl.dsn_advertised && strcmpic(name, US"NOTIFY") == 0)
5229 /* Check if the notify flags have been already set */
5232 done = synprot_error(L_smtp_syntax_error, 501, NULL,
5233 US"NOTIFY can be specified once only");
5236 if (strcmpic(value, US"NEVER") == 0)
5237 dsn_flags |= rf_notify_never;
5244 while (*pp != 0 && *pp != ',') pp++;
5245 if (*pp == ',') *pp++ = 0;
5246 if (strcmpic(p, US"SUCCESS") == 0)
5248 DEBUG(D_receive) debug_printf("DSN: Setting notify success\n");
5249 dsn_flags |= rf_notify_success;
5251 else if (strcmpic(p, US"FAILURE") == 0)
5253 DEBUG(D_receive) debug_printf("DSN: Setting notify failure\n");
5254 dsn_flags |= rf_notify_failure;
5256 else if (strcmpic(p, US"DELAY") == 0)
5258 DEBUG(D_receive) debug_printf("DSN: Setting notify delay\n");
5259 dsn_flags |= rf_notify_delay;
5263 /* Catch any strange values */
5264 done = synprot_error(L_smtp_syntax_error, 501, NULL,
5265 US"Invalid value for NOTIFY parameter");
5270 DEBUG(D_receive) debug_printf("DSN Flags: %x\n", dsn_flags);
5274 /* Unknown option. Stick back the terminator characters and break
5275 the loop. An error for a malformed address will occur. */
5279 DEBUG(D_receive) debug_printf("Invalid RCPT option: %s : %s\n", name, value);
5286 /* Apply SMTP rewriting then extract the working address. Don't allow "<>"
5287 as a recipient address */
5289 recipient = rewrite_existflags & rewrite_smtp
5290 /* deconst ok as smtp_cmd_data was not const */
5291 ? US rewrite_one(smtp_cmd_data, rewrite_smtp, NULL, FALSE, US"",
5292 global_rewrite_rules)
5295 if (!(recipient = parse_extract_address(recipient, &errmess, &start, &end,
5296 &recipient_domain, FALSE)))
5298 done = synprot_error(L_smtp_syntax_error, 501, smtp_cmd_data, errmess);
5303 /* If the recipient address is unqualified, reject it, unless this is a
5304 locally generated message. However, unqualified addresses are permitted
5305 from a configured list of hosts and nets - typically when behaving as
5306 MUAs rather than MTAs. Sad that SMTP is used for both types of traffic,
5307 really. The flag is set at the start of the SMTP connection.
5309 RFC 1123 talks about supporting "the reserved mailbox postmaster"; I always
5310 assumed this meant "reserved local part", but the revision of RFC 821 and
5311 friends now makes it absolutely clear that it means *mailbox*. Consequently
5312 we must always qualify this address, regardless. */
5314 if (!recipient_domain)
5315 if (!(recipient_domain = qualify_recipient(&recipient, smtp_cmd_data,
5322 /* Check maximum allowed */
5324 if (rcpt_count+1 < 0 || rcpt_count > recipients_max && recipients_max > 0)
5326 if (recipients_max_reject)
5329 smtp_printf("552 too many recipients\r\n", FALSE);
5331 log_write(0, LOG_MAIN|LOG_REJECT, "too many recipients: message "
5332 "rejected: sender=<%s> %s", sender_address, host_and_ident(TRUE));
5337 smtp_printf("452 too many recipients\r\n", FALSE);
5339 log_write(0, LOG_MAIN|LOG_REJECT, "too many recipients: excess "
5340 "temporarily rejected: sender=<%s> %s", sender_address,
5341 host_and_ident(TRUE));
5348 /* If we have passed the threshold for rate limiting, apply the current
5349 delay, and update it for next time, provided this is a limited host. */
5351 if (rcpt_count > smtp_rlr_threshold &&
5352 verify_check_host(&smtp_ratelimit_hosts) == OK)
5354 DEBUG(D_receive) debug_printf("rate limit RCPT: delay %.3g sec\n",
5355 smtp_delay_rcpt/1000.0);
5356 millisleep((int)smtp_delay_rcpt);
5357 smtp_delay_rcpt *= smtp_rlr_factor;
5358 if (smtp_delay_rcpt > (double)smtp_rlr_limit)
5359 smtp_delay_rcpt = (double)smtp_rlr_limit;
5362 /* If the MAIL ACL discarded all the recipients, we bypass ACL checking
5363 for them. Otherwise, check the access control list for this recipient. As
5364 there may be a delay in this, re-check for a synchronization error
5365 afterwards, unless pipelining was advertised. */
5367 if (f.recipients_discarded)
5370 if ( (rc = acl_check(ACL_WHERE_RCPT, recipient, acl_smtp_rcpt, &user_msg,
5372 && !f.smtp_in_pipelining_advertised && !check_sync())
5375 /* The ACL was happy */
5379 BOOL more = pipeline_response();
5382 smtp_user_msg(US"250", user_msg);
5384 smtp_printf("250 Accepted\r\n", more);
5385 receive_add_recipient(recipient, -1);
5387 /* Set the dsn flags in the recipients_list */
5388 recipients_list[recipients_count-1].orcpt = orcpt;
5389 recipients_list[recipients_count-1].dsn_flags = dsn_flags;
5391 /* DEBUG(D_receive) debug_printf("DSN: orcpt: %s flags: %d\n",
5392 recipients_list[recipients_count-1].orcpt,
5393 recipients_list[recipients_count-1].dsn_flags); */
5396 /* The recipient was discarded */
5398 else if (rc == DISCARD)
5401 smtp_user_msg(US"250", user_msg);
5403 smtp_printf("250 Accepted\r\n", FALSE);
5406 log_write(0, LOG_MAIN|LOG_REJECT, "%s F=<%s> RCPT %s: "
5407 "discarded by %s ACL%s%s", host_and_ident(TRUE),
5408 sender_address_unrewritten ? sender_address_unrewritten : sender_address,
5409 smtp_cmd_argument, f.recipients_discarded ? "MAIL" : "RCPT",
5410 log_msg ? US": " : US"", log_msg ? log_msg : US"");
5413 /* Either the ACL failed the address, or it was deferred. */
5417 if (rc == FAIL) rcpt_fail_count++; else rcpt_defer_count++;
5418 done = smtp_handle_acl_fail(ACL_WHERE_RCPT, rc, user_msg, log_msg);
5423 /* The DATA command is legal only if it follows successful MAIL FROM
5424 and RCPT TO commands. However, if pipelining is advertised, a bad DATA is
5425 not counted as a protocol error if it follows RCPT (which must have been
5426 rejected if there are no recipients.) This function is complete when a
5427 valid DATA command is encountered.
5429 Note concerning the code used: RFC 2821 says this:
5431 - If there was no MAIL, or no RCPT, command, or all such commands
5432 were rejected, the server MAY return a "command out of sequence"
5433 (503) or "no valid recipients" (554) reply in response to the
5436 The example in the pipelining RFC 2920 uses 554, but I use 503 here
5437 because it is the same whether pipelining is in use or not.
5439 If all the RCPT commands that precede DATA provoked the same error message
5440 (often indicating some kind of system error), it is helpful to include it
5441 with the DATA rejection (an idea suggested by Tony Finch). */
5448 if (chunking_state != CHUNKING_OFFERED)
5450 done = synprot_error(L_smtp_protocol_error, 503, NULL,
5451 US"BDAT command used when CHUNKING not advertised");
5455 /* grab size, endmarker */
5457 if (sscanf(CS smtp_cmd_data, "%u %n", &chunking_datasize, &n) < 1)
5459 done = synprot_error(L_smtp_protocol_error, 501, NULL,
5460 US"missing size for BDAT command");
5463 chunking_state = strcmpic(smtp_cmd_data+n, US"LAST") == 0
5464 ? CHUNKING_LAST : CHUNKING_ACTIVE;
5465 chunking_data_left = chunking_datasize;
5466 DEBUG(D_receive) debug_printf("chunking state %d, %d bytes\n",
5467 (int)chunking_state, chunking_data_left);
5469 f.bdat_readers_wanted = TRUE; /* FIXME: redundant vs chunking_state? */
5478 f.bdat_readers_wanted = FALSE;
5480 DATA_BDAT: /* Common code for DATA and BDAT */
5481 #ifndef DISABLE_PIPE_CONNECT
5482 fl.pipe_connect_acceptable = FALSE;
5484 if (!discarded && recipients_count <= 0)
5486 if (fl.rcpt_smtp_response_same && rcpt_smtp_response)
5488 uschar *code = US"503";
5489 int len = Ustrlen(rcpt_smtp_response);
5490 smtp_respond(code, 3, FALSE, US"All RCPT commands were rejected with "
5492 /* Responses from smtp_printf() will have \r\n on the end */
5493 if (len > 2 && rcpt_smtp_response[len-2] == '\r')
5494 rcpt_smtp_response[len-2] = 0;
5495 smtp_respond(code, 3, FALSE, rcpt_smtp_response);
5497 if (f.smtp_in_pipelining_advertised && last_was_rcpt)
5498 smtp_printf("503 Valid RCPT command must precede %s\r\n", FALSE,
5499 smtp_names[smtp_connection_had[SMTP_HBUFF_PREV(smtp_ch_index)]]);
5501 done = synprot_error(L_smtp_protocol_error, 503, NULL,
5502 smtp_connection_had[SMTP_HBUFF_PREV(smtp_ch_index)] == SCH_DATA
5503 ? US"valid RCPT command must precede DATA"
5504 : US"valid RCPT command must precede BDAT");
5506 if (chunking_state > CHUNKING_OFFERED)
5508 bdat_push_receive_functions();
5514 if (toomany && recipients_max_reject)
5516 sender_address = NULL; /* This will allow a new MAIL without RSET */
5517 sender_address_unrewritten = NULL;
5518 smtp_printf("554 Too many recipients\r\n", FALSE);
5520 if (chunking_state > CHUNKING_OFFERED)
5522 bdat_push_receive_functions();
5528 if (chunking_state > CHUNKING_OFFERED)
5529 rc = OK; /* No predata ACL or go-ahead output for BDAT */
5532 /* If there is an ACL, re-check the synchronization afterwards, since the
5533 ACL may have delayed. To handle cutthrough delivery enforce a dummy call
5534 to get the DATA command sent. */
5536 if (!acl_smtp_predata && cutthrough.cctx.sock < 0)
5540 uschar * acl = acl_smtp_predata ? acl_smtp_predata : US"accept";
5541 f.enable_dollar_recipients = TRUE;
5542 rc = acl_check(ACL_WHERE_PREDATA, NULL, acl, &user_msg,
5544 f.enable_dollar_recipients = FALSE;
5545 if (rc == OK && !check_sync())
5549 { /* Either the ACL failed the address, or it was deferred. */
5550 done = smtp_handle_acl_fail(ACL_WHERE_PREDATA, rc, user_msg, log_msg);
5556 smtp_user_msg(US"354", user_msg);
5559 "354 Enter message, ending with \".\" on a line by itself\r\n", FALSE);
5562 if (f.bdat_readers_wanted)
5563 bdat_push_receive_functions();
5566 if (smtp_in) /* all ACKs needed to ramp window up for bulk data */
5567 (void) setsockopt(fileno(smtp_in), IPPROTO_TCP, TCP_QUICKACK,
5568 US &on, sizeof(on));
5571 message_ended = END_NOTENDED; /* Indicate in middle of data */
5582 if (!(address = parse_extract_address(smtp_cmd_data, &errmess,
5583 &start, &end, &recipient_domain, FALSE)))
5585 smtp_printf("501 %s\r\n", FALSE, errmess);
5589 if (!recipient_domain)
5590 if (!(recipient_domain = qualify_recipient(&address, smtp_cmd_data,
5594 if ((rc = acl_check(ACL_WHERE_VRFY, address, acl_smtp_vrfy,
5595 &user_msg, &log_msg)) != OK)
5596 done = smtp_handle_acl_fail(ACL_WHERE_VRFY, rc, user_msg, log_msg);
5600 address_item * addr = deliver_make_addr(address, FALSE);
5602 switch(verify_address(addr, NULL, vopt_is_recipient | vopt_qualify, -1,
5603 -1, -1, NULL, NULL, NULL))
5606 s = string_sprintf("250 <%s> is deliverable", address);
5610 s = (addr->user_message != NULL)?
5611 string_sprintf("451 <%s> %s", address, addr->user_message) :
5612 string_sprintf("451 Cannot resolve <%s> at this time", address);
5616 s = (addr->user_message != NULL)?
5617 string_sprintf("550 <%s> %s", address, addr->user_message) :
5618 string_sprintf("550 <%s> is not deliverable", address);
5619 log_write(0, LOG_MAIN, "VRFY failed for %s %s",
5620 smtp_cmd_argument, host_and_ident(TRUE));
5624 smtp_printf("%s\r\n", FALSE, s);
5632 rc = acl_check(ACL_WHERE_EXPN, NULL, acl_smtp_expn, &user_msg, &log_msg);
5634 done = smtp_handle_acl_fail(ACL_WHERE_EXPN, rc, user_msg, log_msg);
5637 BOOL save_log_testing_mode = f.log_testing_mode;
5638 f.address_test_mode = f.log_testing_mode = TRUE;
5639 (void) verify_address(deliver_make_addr(smtp_cmd_data, FALSE),
5640 smtp_out, vopt_is_recipient | vopt_qualify | vopt_expn, -1, -1, -1,
5642 f.address_test_mode = FALSE;
5643 f.log_testing_mode = save_log_testing_mode; /* true for -bh */
5652 if (!fl.tls_advertised)
5654 done = synprot_error(L_smtp_protocol_error, 503, NULL,
5655 US"STARTTLS command used when not advertised");
5659 /* Apply an ACL check if one is defined */
5661 if ( acl_smtp_starttls
5662 && (rc = acl_check(ACL_WHERE_STARTTLS, NULL, acl_smtp_starttls,
5663 &user_msg, &log_msg)) != OK
5666 done = smtp_handle_acl_fail(ACL_WHERE_STARTTLS, rc, user_msg, log_msg);
5670 /* RFC 2487 is not clear on when this command may be sent, though it
5671 does state that all information previously obtained from the client
5672 must be discarded if a TLS session is started. It seems reasonable to
5673 do an implied RSET when STARTTLS is received. */
5675 incomplete_transaction_log(US"STARTTLS");
5676 cancel_cutthrough_connection(TRUE, US"STARTTLS received");
5677 reset_point = smtp_reset(reset_point);
5679 cmd_list[CMD_LIST_STARTTLS].is_mail_cmd = FALSE;
5681 /* There's an attack where more data is read in past the STARTTLS command
5682 before TLS is negotiated, then assumed to be part of the secure session
5683 when used afterwards; we use segregated input buffers, so are not
5684 vulnerable, but we want to note when it happens and, for sheer paranoia,
5685 ensure that the buffer is "wiped".
5686 Pipelining sync checks will normally have protected us too, unless disabled
5687 by configuration. */
5692 debug_printf("Non-empty input buffer after STARTTLS; naive attack?\n");
5693 if (tls_in.active.sock < 0)
5694 smtp_inend = smtp_inptr = smtp_inbuffer;
5695 /* and if TLS is already active, tls_server_start() should fail */
5698 /* There is nothing we value in the input buffer and if TLS is successfully
5699 negotiated, we won't use this buffer again; if TLS fails, we'll just read
5700 fresh content into it. The buffer contains arbitrary content from an
5701 untrusted remote source; eg: NOOP <shellcode>\r\nSTARTTLS\r\n
5702 It seems safest to just wipe away the content rather than leave it as a
5703 target to jump to. */
5705 memset(smtp_inbuffer, 0, IN_BUFFER_SIZE);
5707 /* Attempt to start up a TLS session, and if successful, discard all
5708 knowledge that was obtained previously. At least, that's what the RFC says,
5709 and that's what happens by default. However, in order to work round YAEB,
5710 there is an option to remember the esmtp state. Sigh.
5712 We must allow for an extra EHLO command and an extra AUTH command after
5713 STARTTLS that don't add to the nonmail command count. */
5716 if ((rc = tls_server_start(&s)) == OK)
5718 if (!tls_remember_esmtp)
5719 fl.helo_seen = fl.esmtp = fl.auth_advertised = f.smtp_in_pipelining_advertised = FALSE;
5720 cmd_list[CMD_LIST_EHLO].is_mail_cmd = TRUE;
5721 cmd_list[CMD_LIST_AUTH].is_mail_cmd = TRUE;
5722 cmd_list[CMD_LIST_TLS_AUTH].is_mail_cmd = TRUE;
5723 if (sender_helo_name)
5725 sender_helo_name = NULL;
5726 host_build_sender_fullhost(); /* Rebuild */
5727 set_process_info("handling incoming TLS connection from %s",
5728 host_and_ident(FALSE));
5731 (sender_host_address ? protocols : protocols_local)
5733 ? pextend + (sender_host_authenticated ? pauthed : 0)
5735 + (tls_in.active.sock >= 0 ? pcrpted : 0)
5738 sender_host_auth_pubname = sender_host_authenticated = NULL;
5739 authenticated_id = NULL;
5740 sync_cmd_limit = NON_SYNC_CMD_NON_PIPELINING;
5741 DEBUG(D_tls) debug_printf("TLS active\n");
5742 break; /* Successful STARTTLS */
5745 (void) smtp_log_tls_fail(s);
5747 /* Some local configuration problem was discovered before actually trying
5748 to do a TLS handshake; give a temporary error. */
5752 smtp_printf("454 TLS currently unavailable\r\n", FALSE);
5756 /* Hard failure. Reject everything except QUIT or closed connection. One
5757 cause for failure is a nested STARTTLS, in which case tls_in.active remains
5758 set, but we must still reject all incoming commands. Another is a handshake
5759 failure - and there may some encrypted data still in the pipe to us, which we
5760 see as garbage commands. */
5762 DEBUG(D_tls) debug_printf("TLS failed to start\n");
5763 while (done <= 0) switch(smtp_read_command(FALSE, GETC_BUFFER_UNLIMITED))
5766 log_write(L_smtp_connection, LOG_MAIN, "%s closed by EOF",
5767 smtp_get_connection_info());
5768 smtp_notquit_exit(US"tls-failed", NULL, NULL);
5772 /* It is perhaps arguable as to which exit ACL should be called here,
5773 but as it is probably a situation that almost never arises, it
5774 probably doesn't matter. We choose to call the real QUIT ACL, which in
5775 some sense is perhaps "right". */
5778 f.smtp_in_quit = TRUE;
5781 && ((rc = acl_check(ACL_WHERE_QUIT, NULL, acl_smtp_quit, &user_msg,
5782 &log_msg)) == ERROR))
5783 log_write(0, LOG_MAIN|LOG_PANIC, "ACL for QUIT returned ERROR: %s",
5786 smtp_respond(US"221", 3, TRUE, user_msg);
5788 smtp_printf("221 %s closing connection\r\n", FALSE, smtp_active_hostname);
5789 log_write(L_smtp_connection, LOG_MAIN, "%s closed by QUIT",
5790 smtp_get_connection_info());
5795 smtp_printf("554 Security failure\r\n", FALSE);
5798 tls_close(NULL, TLS_SHUTDOWN_NOWAIT);
5803 /* The ACL for QUIT is provided for gathering statistical information or
5804 similar; it does not affect the response code, but it can supply a custom
5808 smtp_quit_handler(&user_msg, &log_msg);
5814 smtp_rset_handler();
5815 cancel_cutthrough_connection(TRUE, US"RSET received");
5816 reset_point = smtp_reset(reset_point);
5823 smtp_printf("250 OK\r\n", FALSE);
5827 /* Show ETRN/EXPN/VRFY if there's an ACL for checking hosts; if actually
5828 used, a check will be done for permitted hosts. Show STARTTLS only if not
5829 already in a TLS session and if it would be advertised in the EHLO
5834 smtp_printf("214-Commands supported:\r\n", TRUE);
5838 Ustrcat(buffer, US" AUTH");
5840 if (tls_in.active.sock < 0 &&
5841 verify_check_host(&tls_advertise_hosts) != FAIL)
5842 Ustrcat(buffer, US" STARTTLS");
5844 Ustrcat(buffer, US" HELO EHLO MAIL RCPT DATA BDAT");
5845 Ustrcat(buffer, US" NOOP QUIT RSET HELP");
5846 if (acl_smtp_etrn) Ustrcat(buffer, US" ETRN");
5847 if (acl_smtp_expn) Ustrcat(buffer, US" EXPN");
5848 if (acl_smtp_vrfy) Ustrcat(buffer, US" VRFY");
5849 smtp_printf("214%s\r\n", FALSE, buffer);
5855 incomplete_transaction_log(US"connection lost");
5856 smtp_notquit_exit(US"connection-lost", US"421",
5857 US"%s lost input connection", smtp_active_hostname);
5859 /* Don't log by default unless in the middle of a message, as some mailers
5860 just drop the call rather than sending QUIT, and it clutters up the logs.
5863 if (sender_address || recipients_count > 0)
5864 log_write(L_lost_incoming_connection, LOG_MAIN,
5865 "unexpected %s while reading SMTP command from %s%s%s D=%s",
5866 f.sender_host_unknown ? "EOF" : "disconnection",
5867 f.tcp_in_fastopen_logged
5870 ? f.tcp_in_fastopen_data ? US"TFO* " : US"TFO "
5872 host_and_ident(FALSE), smtp_read_error,
5873 string_timesince(&smtp_connection_start)
5877 log_write(L_smtp_connection, LOG_MAIN, "%s %slost%s D=%s",
5878 smtp_get_connection_info(),
5879 f.tcp_in_fastopen && !f.tcp_in_fastopen_logged ? US"TFO " : US"",
5881 string_timesince(&smtp_connection_start)
5892 done = synprot_error(L_smtp_protocol_error, 503, NULL,
5893 US"ETRN is not permitted inside a transaction");
5897 log_write(L_etrn, LOG_MAIN, "ETRN %s received from %s", smtp_cmd_argument,
5898 host_and_ident(FALSE));
5900 if ((rc = acl_check(ACL_WHERE_ETRN, NULL, acl_smtp_etrn,
5901 &user_msg, &log_msg)) != OK)
5903 done = smtp_handle_acl_fail(ACL_WHERE_ETRN, rc, user_msg, log_msg);
5907 /* Compute the serialization key for this command. */
5909 etrn_serialize_key = string_sprintf("etrn-%s\n", smtp_cmd_data);
5911 /* If a command has been specified for running as a result of ETRN, we
5912 permit any argument to ETRN. If not, only the # standard form is permitted,
5913 since that is strictly the only kind of ETRN that can be implemented
5914 according to the RFC. */
5916 if (smtp_etrn_command)
5920 etrn_command = smtp_etrn_command;
5921 deliver_domain = smtp_cmd_data;
5922 rc = transport_set_up_command(&argv, smtp_etrn_command, TRUE, 0, NULL,
5923 FALSE, US"ETRN processing", &error);
5924 deliver_domain = NULL;
5927 log_write(0, LOG_MAIN|LOG_PANIC, "failed to set up ETRN command: %s",
5929 smtp_printf("458 Internal failure\r\n", FALSE);
5934 /* Else set up to call Exim with the -R option. */
5938 if (*smtp_cmd_data++ != '#')
5940 done = synprot_error(L_smtp_syntax_error, 501, NULL,
5941 US"argument must begin with #");
5944 etrn_command = US"exim -R";
5945 argv = CUSS child_exec_exim(CEE_RETURN_ARGV, TRUE, NULL, TRUE,
5946 *queue_name ? 4 : 2,
5947 US"-R", smtp_cmd_data,
5948 US"-MCG", queue_name);
5951 /* If we are host-testing, don't actually do anything. */
5957 debug_printf("ETRN command is: %s\n", etrn_command);
5958 debug_printf("ETRN command execution skipped\n");
5960 if (user_msg == NULL) smtp_printf("250 OK\r\n", FALSE);
5961 else smtp_user_msg(US"250", user_msg);
5966 /* If ETRN queue runs are to be serialized, check the database to
5967 ensure one isn't already running. */
5969 if (smtp_etrn_serialize && !enq_start(etrn_serialize_key, 1))
5971 smtp_printf("458 Already processing %s\r\n", FALSE, smtp_cmd_data);
5975 /* Fork a child process and run the command. We don't want to have to
5976 wait for the process at any point, so set SIGCHLD to SIG_IGN before
5977 forking. It should be set that way anyway for external incoming SMTP,
5978 but we save and restore to be tidy. If serialization is required, we
5979 actually run the command in yet another process, so we can wait for it
5980 to complete and then remove the serialization lock. */
5982 oldsignal = signal(SIGCHLD, SIG_IGN);
5984 if ((pid = exim_fork(US"etrn-command")) == 0)
5986 smtp_input = FALSE; /* This process is not associated with the */
5987 (void)fclose(smtp_in); /* SMTP call any more. */
5988 (void)fclose(smtp_out);
5990 signal(SIGCHLD, SIG_DFL); /* Want to catch child */
5992 /* If not serializing, do the exec right away. Otherwise, fork down
5993 into another process. */
5995 if ( !smtp_etrn_serialize
5996 || (pid = exim_fork(US"etrn-serialised-command")) == 0)
5998 DEBUG(D_exec) debug_print_argv(argv);
5999 exim_nullstd(); /* Ensure std{in,out,err} exist */
6000 /* argv[0] should be untainted, from child_exec_exim() */
6001 execv(CS argv[0], (char *const *)argv);
6002 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "exec of \"%s\" (ETRN) failed: %s",
6003 etrn_command, strerror(errno));
6004 _exit(EXIT_FAILURE); /* paranoia */
6007 /* Obey this if smtp_serialize and the 2nd fork yielded non-zero. That
6008 is, we are in the first subprocess, after forking again. All we can do
6009 for a failing fork is to log it. Otherwise, wait for the 2nd process to
6010 complete, before removing the serialization. */
6013 log_write(0, LOG_MAIN|LOG_PANIC, "2nd fork for serialized ETRN "
6014 "failed: %s", strerror(errno));
6018 DEBUG(D_any) debug_printf("waiting for serialized ETRN process %d\n",
6020 (void)wait(&status);
6021 DEBUG(D_any) debug_printf("serialized ETRN process %d ended\n",
6025 enq_end(etrn_serialize_key);
6026 exim_underbar_exit(EXIT_SUCCESS);
6029 /* Back in the top level SMTP process. Check that we started a subprocess
6030 and restore the signal state. */
6034 log_write(0, LOG_MAIN|LOG_PANIC, "fork of process for ETRN failed: %s",
6036 smtp_printf("458 Unable to fork process\r\n", FALSE);
6037 if (smtp_etrn_serialize) enq_end(etrn_serialize_key);
6041 smtp_printf("250 OK\r\n", FALSE);
6043 smtp_user_msg(US"250", user_msg);
6045 signal(SIGCHLD, oldsignal);
6050 done = synprot_error(L_smtp_syntax_error, 501, NULL,
6051 US"unexpected argument data");
6055 /* This currently happens only for NULLs, but could be extended. */
6058 done = synprot_error(L_smtp_syntax_error, 0, NULL, /* Just logs */
6059 US"NUL character(s) present (shown as '?')");
6060 smtp_printf("501 NUL characters are not allowed in SMTP commands\r\n",
6067 if (smtp_inend >= smtp_inbuffer + IN_BUFFER_SIZE)
6068 smtp_inend = smtp_inbuffer + IN_BUFFER_SIZE - 1;
6069 c = smtp_inend - smtp_inptr;
6070 if (c > 150) c = 150; /* limit logged amount */
6072 incomplete_transaction_log(US"sync failure");
6073 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP protocol synchronization error "
6074 "(next input sent too soon: pipelining was%s advertised): "
6075 "rejected \"%s\" %s next input=\"%s\"",
6076 f.smtp_in_pipelining_advertised ? "" : " not",
6077 smtp_cmd_buffer, host_and_ident(TRUE),
6078 string_printing(smtp_inptr));
6079 smtp_notquit_exit(US"synchronization-error", US"554",
6080 US"SMTP synchronization error");
6081 done = 1; /* Pretend eof - drops connection */
6085 case TOO_MANY_NONMAIL_CMD:
6086 s = smtp_cmd_buffer;
6087 while (*s != 0 && !isspace(*s)) s++;
6088 incomplete_transaction_log(US"too many non-mail commands");
6089 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
6090 "nonmail commands (last was \"%.*s\")", host_and_ident(FALSE),
6091 (int)(s - smtp_cmd_buffer), smtp_cmd_buffer);
6092 smtp_notquit_exit(US"bad-commands", US"554", US"Too many nonmail commands");
6093 done = 1; /* Pretend eof - drops connection */
6096 #ifdef SUPPORT_PROXY
6097 case PROXY_FAIL_IGNORE_CMD:
6098 smtp_printf("503 Command refused, required Proxy negotiation failed\r\n", FALSE);
6103 if (unknown_command_count++ >= smtp_max_unknown_commands)
6105 log_write(L_smtp_syntax_error, LOG_MAIN,
6106 "SMTP syntax error in \"%s\" %s %s",
6107 string_printing(smtp_cmd_buffer), host_and_ident(TRUE),
6108 US"unrecognized command");
6109 incomplete_transaction_log(US"unrecognized command");
6110 smtp_notquit_exit(US"bad-commands", US"500",
6111 US"Too many unrecognized commands");
6113 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
6114 "unrecognized commands (last was \"%s\")", host_and_ident(FALSE),
6115 string_printing(smtp_cmd_buffer));
6118 done = synprot_error(L_smtp_syntax_error, 500, NULL,
6119 US"unrecognized command");
6123 /* This label is used by goto's inside loops that want to break out to
6124 the end of the command-processing loop. */
6127 last_was_rej_mail = was_rej_mail; /* Remember some last commands for */
6128 last_was_rcpt = was_rcpt; /* protocol error handling */
6131 return done - 2; /* Convert yield values */
6137 authres_smtpauth(gstring * g)
6139 if (!sender_host_authenticated)
6142 g = string_append(g, 2, US";\n\tauth=pass (", sender_host_auth_pubname);
6144 if (Ustrcmp(sender_host_auth_pubname, "tls") == 0)
6145 g = authenticated_id
6146 ? string_append(g, 2, US") x509.auth=", authenticated_id)
6147 : string_cat(g, US") reason=x509.auth");
6149 g = authenticated_id
6150 ? string_append(g, 2, US") smtp.auth=", authenticated_id)
6151 : string_cat(g, US", no id saved)");
6153 if (authenticated_sender)
6154 g = string_append(g, 2, US" smtp.mailfrom=", authenticated_sender);
6162 /* End of smtp_in.c */