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. */
9 /* Functions for handling an incoming SMTP call. */
16 /* Initialize for TCP wrappers if so configured. It appears that the macro
17 HAVE_IPV6 is used in some versions of the tcpd.h header, so we unset it before
18 including that header, and restore its value afterwards. */
20 #ifdef USE_TCP_WRAPPERS
23 #define EXIM_HAVE_IPV6
29 #define HAVE_IPV6 TRUE
32 int allow_severity = LOG_INFO;
33 int deny_severity = LOG_NOTICE;
34 uschar *tcp_wrappers_name;
38 /* Size of buffer for reading SMTP commands. We used to use 512, as defined
39 by RFC 821. However, RFC 1869 specifies that this must be increased for SMTP
40 commands that accept arguments, and this in particular applies to AUTH, where
41 the data can be quite long. More recently this value was 2048 in Exim;
42 however, RFC 4954 (circa 2007) recommends 12288 bytes to handle AUTH. Clients
43 such as Thunderbird will send an AUTH with an initial-response for GSSAPI.
44 The maximum size of a Kerberos ticket under Windows 2003 is 12000 bytes, and
45 we need room to handle large base64-encoded AUTHs for GSSAPI.
48 #define SMTP_CMD_BUFFER_SIZE 16384
50 /* Size of buffer for reading SMTP incoming packets */
52 #define IN_BUFFER_SIZE 8192
54 /* Structure for SMTP command list */
61 short int is_mail_cmd;
64 /* Codes for identifying commands. We order them so that those that come first
65 are those for which synchronization is always required. Checking this can help
69 /* These commands are required to be synchronized, i.e. to be the last in a
70 block of commands when pipelining. */
72 HELO_CMD, EHLO_CMD, DATA_CMD, /* These are listed in the pipelining */
73 VRFY_CMD, EXPN_CMD, NOOP_CMD, /* RFC as requiring synchronization */
74 ETRN_CMD, /* This by analogy with TURN from the RFC */
75 STARTTLS_CMD, /* Required by the STARTTLS RFC */
76 TLS_AUTH_CMD, /* auto-command at start of SSL */
78 /* This is a dummy to identify the non-sync commands when pipelining */
80 NON_SYNC_CMD_PIPELINING,
82 /* These commands need not be synchronized when pipelining */
84 MAIL_CMD, RCPT_CMD, RSET_CMD,
86 /* This is a dummy to identify the non-sync commands when not pipelining */
88 NON_SYNC_CMD_NON_PIPELINING,
90 /* RFC3030 section 2: "After all MAIL and RCPT responses are collected and
91 processed the message is sent using a series of BDAT commands"
92 implies that BDAT should be synchronized. However, we see Google, at least,
93 sending MAIL,RCPT,BDAT-LAST in a single packet, clearly not waiting for
94 processing of the RCPT response(s). We shall do the same, and not require
95 synch for BDAT. Worse, as the chunk may (very likely will) follow the
96 command-header in the same packet we cannot do the usual "is there any
97 follow-on data after the command line" even for non-pipeline mode.
98 So we'll need an explicit check after reading the expected chunk amount
99 when non-pipe, before sending the ACK. */
103 /* I have been unable to find a statement about the use of pipelining
104 with AUTH, so to be on the safe side it is here, though I kind of feel
105 it should be up there with the synchronized commands. */
109 /* I'm not sure about these, but I don't think they matter. */
114 PROXY_FAIL_IGNORE_CMD,
117 /* These are specials that don't correspond to actual commands */
119 EOF_CMD, OTHER_CMD, BADARG_CMD, BADCHAR_CMD, BADSYN_CMD,
120 TOO_MANY_NONMAIL_CMD };
123 /* This is a convenience macro for adding the identity of an SMTP command
124 to the circular buffer that holds a list of the last n received. */
127 smtp_connection_had[smtp_ch_index++] = n; \
128 if (smtp_ch_index >= SMTP_HBUFF_SIZE) smtp_ch_index = 0
131 /*************************************************
132 * Local static variables *
133 *************************************************/
136 BOOL auth_advertised :1;
138 BOOL tls_advertised :1;
140 BOOL dsn_advertised :1;
142 BOOL helo_verify_required :1;
145 BOOL helo_accept_junk :1;
146 #ifndef DISABLE_PIPE_CONNECT
147 BOOL pipe_connect_acceptable :1;
149 BOOL rcpt_smtp_response_same :1;
150 BOOL rcpt_in_progress :1;
151 BOOL smtp_exit_function_called :1;
153 BOOL smtputf8_advertised :1;
156 .helo_verify_required = FALSE,
157 .helo_verify = FALSE,
158 .smtp_exit_function_called = FALSE,
161 static auth_instance *authenticated_by;
162 static int count_nonmail;
163 static int nonmail_command_count;
164 static int synprot_error_count;
165 static int unknown_command_count;
166 static int sync_cmd_limit;
167 static int smtp_write_error = 0;
169 static uschar *rcpt_smtp_response;
170 static uschar *smtp_data_buffer;
171 static uschar *smtp_cmd_data;
173 /* We need to know the position of RSET, HELO, EHLO, AUTH, and STARTTLS. Their
174 final fields of all except AUTH are forced TRUE at the start of a new message
175 setup, to allow one of each between messages that is not counted as a nonmail
176 command. (In fact, only one of HELO/EHLO is not counted.) Also, we have to
177 allow a new EHLO after starting up TLS.
179 AUTH is "falsely" labelled as a mail command initially, so that it doesn't get
180 counted. However, the flag is changed when AUTH is received, so that multiple
181 failing AUTHs will eventually hit the limit. After a successful AUTH, another
182 AUTH is already forbidden. After a TLS session is started, AUTH's flag is again
183 forced TRUE, to allow for the re-authentication that can happen at that point.
185 QUIT is also "falsely" labelled as a mail command so that it doesn't up the
186 count of non-mail commands and possibly provoke an error.
188 tls_auth is a pseudo-command, never expected in input. It is activated
189 on TLS startup and looks for a tls authenticator. */
191 static smtp_cmd_list cmd_list[] = {
192 /* name len cmd has_arg is_mail_cmd */
194 { "rset", sizeof("rset")-1, RSET_CMD, FALSE, FALSE }, /* First */
195 { "helo", sizeof("helo")-1, HELO_CMD, TRUE, FALSE },
196 { "ehlo", sizeof("ehlo")-1, EHLO_CMD, TRUE, FALSE },
197 { "auth", sizeof("auth")-1, AUTH_CMD, TRUE, TRUE },
199 { "starttls", sizeof("starttls")-1, STARTTLS_CMD, FALSE, FALSE },
200 { "tls_auth", 0, TLS_AUTH_CMD, FALSE, FALSE },
203 /* If you change anything above here, also fix the definitions below. */
205 { "mail from:", sizeof("mail from:")-1, MAIL_CMD, TRUE, TRUE },
206 { "rcpt to:", sizeof("rcpt to:")-1, RCPT_CMD, TRUE, TRUE },
207 { "data", sizeof("data")-1, DATA_CMD, FALSE, TRUE },
208 { "bdat", sizeof("bdat")-1, BDAT_CMD, TRUE, TRUE },
209 { "quit", sizeof("quit")-1, QUIT_CMD, FALSE, TRUE },
210 { "noop", sizeof("noop")-1, NOOP_CMD, TRUE, FALSE },
211 { "etrn", sizeof("etrn")-1, ETRN_CMD, TRUE, FALSE },
212 { "vrfy", sizeof("vrfy")-1, VRFY_CMD, TRUE, FALSE },
213 { "expn", sizeof("expn")-1, EXPN_CMD, TRUE, FALSE },
214 { "help", sizeof("help")-1, HELP_CMD, TRUE, FALSE }
217 static smtp_cmd_list *cmd_list_end =
218 cmd_list + sizeof(cmd_list)/sizeof(smtp_cmd_list);
220 #define CMD_LIST_RSET 0
221 #define CMD_LIST_HELO 1
222 #define CMD_LIST_EHLO 2
223 #define CMD_LIST_AUTH 3
224 #define CMD_LIST_STARTTLS 4
225 #define CMD_LIST_TLS_AUTH 5
227 /* This list of names is used for performing the smtp_no_mail logging action.
228 It must be kept in step with the SCH_xxx enumerations. */
230 uschar * smtp_names[] =
232 US"NONE", US"AUTH", US"DATA", US"BDAT", US"EHLO", US"ETRN", US"EXPN",
233 US"HELO", US"HELP", US"MAIL", US"NOOP", US"QUIT", US"RCPT", US"RSET",
234 US"STARTTLS", US"VRFY" };
236 static uschar *protocols_local[] = {
237 US"local-smtp", /* HELO */
238 US"local-smtps", /* The rare case EHLO->STARTTLS->HELO */
239 US"local-esmtp", /* EHLO */
240 US"local-esmtps", /* EHLO->STARTTLS->EHLO */
241 US"local-esmtpa", /* EHLO->AUTH */
242 US"local-esmtpsa" /* EHLO->STARTTLS->EHLO->AUTH */
244 static uschar *protocols[] = {
246 US"smtps", /* The rare case EHLO->STARTTLS->HELO */
247 US"esmtp", /* EHLO */
248 US"esmtps", /* EHLO->STARTTLS->EHLO */
249 US"esmtpa", /* EHLO->AUTH */
250 US"esmtpsa" /* EHLO->STARTTLS->EHLO->AUTH */
255 #define pcrpted 1 /* added to pextend or pnormal */
256 #define pauthed 2 /* added to pextend */
258 /* Sanity check and validate optional args to MAIL FROM: envelope */
261 ENV_MAIL_OPT_SIZE, ENV_MAIL_OPT_BODY, ENV_MAIL_OPT_AUTH,
265 ENV_MAIL_OPT_RET, ENV_MAIL_OPT_ENVID,
271 uschar * name; /* option requested during MAIL cmd */
272 int value; /* enum type */
273 BOOL need_value; /* TRUE requires value (name=value pair format)
274 FALSE is a singleton */
276 static env_mail_type_t env_mail_type_list[] = {
277 { US"SIZE", ENV_MAIL_OPT_SIZE, TRUE },
278 { US"BODY", ENV_MAIL_OPT_BODY, TRUE },
279 { US"AUTH", ENV_MAIL_OPT_AUTH, TRUE },
281 { US"PRDR", ENV_MAIL_OPT_PRDR, FALSE },
283 { US"RET", ENV_MAIL_OPT_RET, TRUE },
284 { US"ENVID", ENV_MAIL_OPT_ENVID, TRUE },
286 { US"SMTPUTF8",ENV_MAIL_OPT_UTF8, FALSE }, /* rfc6531 */
288 /* keep this the last entry */
289 { US"NULL", ENV_MAIL_OPT_NULL, FALSE },
292 /* When reading SMTP from a remote host, we have to use our own versions of the
293 C input-reading functions, in order to be able to flush the SMTP output only
294 when about to read more data from the socket. This is the only way to get
295 optimal performance when the client is using pipelining. Flushing for every
296 command causes a separate packet and reply packet each time; saving all the
297 responses up (when pipelining) combines them into one packet and one response.
299 For simplicity, these functions are used for *all* SMTP input, not only when
300 receiving over a socket. However, after setting up a secure socket (SSL), input
301 is read via the OpenSSL library, and another set of functions is used instead
304 These functions are set in the receive_getc etc. variables and called with the
305 same interface as the C functions. However, since there can only ever be
306 one incoming SMTP call, we just use a single buffer and flags. There is no need
307 to implement a complicated private FILE-like structure.*/
309 static uschar *smtp_inbuffer;
310 static uschar *smtp_inptr;
311 static uschar *smtp_inend;
312 static int smtp_had_eof;
313 static int smtp_had_error;
316 /* forward declarations */
317 static int smtp_read_command(BOOL check_sync, unsigned buffer_lim);
318 static int synprot_error(int type, int code, uschar *data, uschar *errmess);
319 static void smtp_quit_handler(uschar **, uschar **);
320 static void smtp_rset_handler(void);
322 /*************************************************
323 * Log incomplete transactions *
324 *************************************************/
326 /* This function is called after a transaction has been aborted by RSET, QUIT,
327 connection drops or other errors. It logs the envelope information received
328 so far in order to preserve address verification attempts.
330 Argument: string to indicate what aborted the transaction
335 incomplete_transaction_log(uschar *what)
337 if (!sender_address /* No transaction in progress */
338 || !LOGGING(smtp_incomplete_transaction))
341 /* Build list of recipients for logging */
343 if (recipients_count > 0)
345 raw_recipients = store_get(recipients_count * sizeof(uschar *), GET_UNTAINTED);
346 for (int i = 0; i < recipients_count; i++)
347 raw_recipients[i] = recipients_list[i].address;
348 raw_recipients_count = recipients_count;
351 log_write(L_smtp_incomplete_transaction, LOG_MAIN|LOG_SENDER|LOG_RECIPIENTS,
352 "%s incomplete transaction (%s)", host_and_ident(TRUE), what);
359 smtp_command_timeout_exit(void)
361 log_write(L_lost_incoming_connection,
362 LOG_MAIN, "SMTP command timeout on%s connection from %s",
363 tls_in.active.sock >= 0 ? " TLS" : "", host_and_ident(FALSE));
364 if (smtp_batched_input)
365 moan_smtp_batch(NULL, "421 SMTP command timeout"); /* Does not return */
366 smtp_notquit_exit(US"command-timeout", US"421",
367 US"%s: SMTP command timeout - closing connection",
368 smtp_active_hostname);
369 exim_exit(EXIT_FAILURE);
373 smtp_command_sigterm_exit(void)
375 log_write(0, LOG_MAIN, "%s closed after SIGTERM", smtp_get_connection_info());
376 if (smtp_batched_input)
377 moan_smtp_batch(NULL, "421 SIGTERM received"); /* Does not return */
378 smtp_notquit_exit(US"signal-exit", US"421",
379 US"%s: Service not available - closing connection", smtp_active_hostname);
380 exim_exit(EXIT_FAILURE);
384 smtp_data_timeout_exit(void)
386 log_write(L_lost_incoming_connection,
387 LOG_MAIN, "SMTP data timeout (message abandoned) on connection from %s F=<%s>",
388 sender_fullhost ? sender_fullhost : US"local process", sender_address);
389 receive_bomb_out(US"data-timeout", US"SMTP incoming data timeout");
390 /* Does not return */
394 smtp_data_sigint_exit(void)
396 log_write(0, LOG_MAIN, "%s closed after %s",
397 smtp_get_connection_info(), had_data_sigint == SIGTERM ? "SIGTERM":"SIGINT");
398 receive_bomb_out(US"signal-exit",
399 US"Service not available - SIGTERM or SIGINT received");
400 /* Does not return */
404 /******************************************************************************/
405 /* SMTP input buffer handling. Most of these are similar to stdio routines. */
410 /* Set up the buffer for inputting using direct read() calls, and arrange to
411 call the local functions instead of the standard C ones. Place a NUL at the
412 end of the buffer to safety-stop C-string reads from it. */
414 if (!(smtp_inbuffer = US malloc(IN_BUFFER_SIZE)))
415 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "malloc() failed for SMTP input buffer");
416 smtp_inbuffer[IN_BUFFER_SIZE-1] = '\0';
418 smtp_inptr = smtp_inend = smtp_inbuffer;
419 smtp_had_eof = smtp_had_error = 0;
424 /* Refill the buffer, and notify DKIM verification code.
425 Return false for error or EOF.
429 smtp_refill(unsigned lim)
433 if (!smtp_out) return FALSE;
435 if (smtp_receive_timeout > 0) ALARM(smtp_receive_timeout);
437 /* Limit amount read, so non-message data is not fed to DKIM.
438 Take care to not touch the safety NUL at the end of the buffer. */
440 rc = read(fileno(smtp_in), smtp_inbuffer, MIN(IN_BUFFER_SIZE-1, lim));
442 if (smtp_receive_timeout > 0) ALARM_CLR(0);
445 /* Must put the error text in fixed store, because this might be during
446 header reading, where it releases unused store above the header. */
449 if (had_command_timeout) /* set by signal handler */
450 smtp_command_timeout_exit(); /* does not return */
451 if (had_command_sigterm)
452 smtp_command_sigterm_exit();
453 if (had_data_timeout)
454 smtp_data_timeout_exit();
456 smtp_data_sigint_exit();
458 smtp_had_error = save_errno;
459 smtp_read_error = string_copy_perm(
460 string_sprintf(" (error: %s)", strerror(save_errno)), FALSE);
467 dkim_exim_verify_feed(smtp_inbuffer, rc);
469 smtp_inend = smtp_inbuffer + rc;
470 smtp_inptr = smtp_inbuffer;
475 /* Check if there is buffered data */
480 return smtp_inptr < smtp_inend;
483 /* SMTP version of getc()
485 This gets the next byte from the SMTP input buffer. If the buffer is empty,
486 it flushes the output, and refills the buffer, with a timeout. The signal
487 handler is set appropriately by the calling function. This function is not used
488 after a connection has negotiated itself into an TLS/SSL state.
490 Arguments: lim Maximum amount to read/buffer
491 Returns: the next character or EOF
495 smtp_getc(unsigned lim)
497 if (!smtp_hasc() && !smtp_refill(lim)) return EOF;
498 return *smtp_inptr++;
501 /* Get many bytes, refilling buffer if needed */
504 smtp_getbuf(unsigned * len)
509 if (!smtp_hasc() && !smtp_refill(*len))
510 { *len = 0; return NULL; }
512 if ((size = smtp_inend - smtp_inptr) > *len) size = *len;
519 /* Copy buffered data to the dkim feed.
520 Called, unless TLS, just before starting to read message headers. */
523 smtp_get_cache(unsigned lim)
526 int n = smtp_inend - smtp_inptr;
530 dkim_exim_verify_feed(smtp_inptr, n);
535 /* SMTP version of ungetc()
536 Puts a character back in the input buffer. Only ever called once.
541 Returns: the character
547 if (smtp_inptr <= smtp_inbuffer) /* NB: NOT smtp_hasc() ! */
548 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "buffer underflow in smtp_ungetc");
555 /* SMTP version of feof()
556 Tests for a previous EOF
559 Returns: non-zero if the eof flag is set
569 /* SMTP version of ferror()
570 Tests for a previous read error, and returns with errno
571 restored to what it was when the error was detected.
574 Returns: non-zero if the error flag is set
580 errno = smtp_had_error;
581 return smtp_had_error;
585 /* Check if a getc will block or not */
588 smtp_could_getc(void)
592 struct timeval tzero = {.tv_sec = 0, .tv_usec = 0};
594 if (smtp_inptr < smtp_inend)
597 fd = fileno(smtp_in);
600 rc = select(fd + 1, (SELECT_ARG2_TYPE *)&fds, NULL, NULL, &tzero);
602 if (rc <= 0) return FALSE; /* Not ready to read */
603 rc = smtp_getc(GETC_BUFFER_UNLIMITED);
604 if (rc < 0) return FALSE; /* End of file or error */
611 /******************************************************************************/
612 /*************************************************
613 * Recheck synchronization *
614 *************************************************/
616 /* Synchronization checks can never be perfect because a packet may be on its
617 way but not arrived when the check is done. Normally, the checks happen when
618 commands are read: Exim ensures that there is no more input in the input buffer.
619 In normal cases, the response to the command will be fast, and there is no
622 However, for some commands an ACL is run, and that can include delays. In those
623 cases, it is useful to do another check on the input just before sending the
624 response. This also applies at the start of a connection. This function does
625 that check by means of the select() function, as long as the facility is not
626 disabled or inappropriate. A failure of select() is ignored.
628 When there is unwanted input, we read it so that it appears in the log of the
632 Returns: TRUE if all is well; FALSE if there is input pending
636 wouldblock_reading(void)
639 if (tls_in.active.sock >= 0)
640 return !tls_could_getc();
643 return !smtp_could_getc();
649 if (!smtp_enforce_sync || !sender_host_address || f.sender_host_notsocket)
652 return wouldblock_reading();
656 /******************************************************************************/
657 /* Variants of the smtp_* input handling functions for use in CHUNKING mode */
659 /* Forward declarations */
660 static inline void bdat_push_receive_functions(void);
661 static inline void bdat_pop_receive_functions(void);
664 /* Get a byte from the smtp input, in CHUNKING mode. Handle ack of the
665 previous BDAT chunk and getting new ones when we run out. Uses the
666 underlying smtp_getc or tls_getc both for that and for getting the
667 (buffered) data byte. EOD signals (an expected) no further data.
668 ERR signals a protocol error, and EOF a closed input stream.
670 Called from read_bdat_smtp() in receive.c for the message body, but also
671 by the headers read loop in receive_msg(); manipulates chunking_state
672 to handle the BDAT command/response.
673 Placed here due to the correlation with the above smtp_getc(), which it wraps,
674 and also by the need to do smtp command/response handling.
676 Arguments: lim (ignored)
677 Returns: the next character or ERR, EOD or EOF
681 bdat_getc(unsigned lim)
683 uschar * user_msg = NULL;
692 if (chunking_data_left > 0)
693 return lwr_receive_getc(chunking_data_left--);
695 bdat_pop_receive_functions();
697 dkim_save = dkim_collect_input;
698 dkim_collect_input = 0;
701 /* Unless PIPELINING was offered, there should be no next command
702 until after we ack that chunk */
704 if (!f.smtp_in_pipelining_advertised && !check_sync())
706 unsigned n = smtp_inend - smtp_inptr;
709 incomplete_transaction_log(US"sync failure");
710 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP protocol synchronization error "
711 "(next input sent too soon: pipelining was not advertised): "
712 "rejected \"%s\" %s next input=\"%s\"%s",
713 smtp_cmd_buffer, host_and_ident(TRUE),
714 string_printing(string_copyn(smtp_inptr, n)),
715 smtp_inend - smtp_inptr > n ? "..." : "");
716 (void) synprot_error(L_smtp_protocol_error, 554, NULL,
717 US"SMTP synchronization error");
718 goto repeat_until_rset;
721 /* If not the last, ack the received chunk. The last response is delayed
722 until after the data ACL decides on it */
724 if (chunking_state == CHUNKING_LAST)
727 dkim_collect_input = dkim_save;
728 dkim_exim_verify_feed(NULL, 0); /* notify EOD */
729 dkim_collect_input = 0;
734 smtp_printf("250 %u byte chunk received\r\n", FALSE, chunking_datasize);
735 chunking_state = CHUNKING_OFFERED;
736 DEBUG(D_receive) debug_printf("chunking state %d\n", (int)chunking_state);
738 /* Expect another BDAT cmd from input. RFC 3030 says nothing about
739 QUIT, RSET or NOOP but handling them seems obvious */
742 switch(smtp_read_command(TRUE, 1))
745 (void) synprot_error(L_smtp_protocol_error, 503, NULL,
746 US"only BDAT permissible after non-LAST BDAT");
749 switch(smtp_read_command(TRUE, 1))
751 case QUIT_CMD: smtp_quit_handler(&user_msg, &log_msg); /*FALLTHROUGH */
752 case EOF_CMD: return EOF;
753 case RSET_CMD: smtp_rset_handler(); return ERR;
754 default: if (synprot_error(L_smtp_protocol_error, 503, NULL,
755 US"only RSET accepted now") > 0)
757 goto repeat_until_rset;
761 smtp_quit_handler(&user_msg, &log_msg);
772 smtp_printf("250 OK\r\n", FALSE);
779 if (sscanf(CS smtp_cmd_data, "%u %n", &chunking_datasize, &n) < 1)
781 (void) synprot_error(L_smtp_protocol_error, 501, NULL,
782 US"missing size for BDAT command");
785 chunking_state = strcmpic(smtp_cmd_data+n, US"LAST") == 0
786 ? CHUNKING_LAST : CHUNKING_ACTIVE;
787 chunking_data_left = chunking_datasize;
788 DEBUG(D_receive) debug_printf("chunking state %d, %d bytes\n",
789 (int)chunking_state, chunking_data_left);
791 if (chunking_datasize == 0)
792 if (chunking_state == CHUNKING_LAST)
796 (void) synprot_error(L_smtp_protocol_error, 504, NULL,
797 US"zero size for BDAT command");
798 goto repeat_until_rset;
801 bdat_push_receive_functions();
803 dkim_collect_input = dkim_save;
805 break; /* to top of main loop */
814 if (chunking_data_left > 0)
815 return lwr_receive_hasc();
820 bdat_getbuf(unsigned * len)
824 if (chunking_data_left <= 0)
825 { *len = 0; return NULL; }
827 if (*len > chunking_data_left) *len = chunking_data_left;
828 buf = lwr_receive_getbuf(len); /* Either smtp_getbuf or tls_getbuf */
829 chunking_data_left -= *len;
834 bdat_flush_data(void)
836 while (chunking_data_left)
838 unsigned n = chunking_data_left;
839 if (!bdat_getbuf(&n)) break;
842 bdat_pop_receive_functions();
843 chunking_state = CHUNKING_OFFERED;
844 DEBUG(D_receive) debug_printf("chunking state %d\n", (int)chunking_state);
849 bdat_push_receive_functions(void)
851 /* push the current receive_* function on the "stack", and
852 replace them by bdat_getc(), which in turn will use the lwr_receive_*
853 functions to do the dirty work. */
854 if (!lwr_receive_getc)
856 lwr_receive_getc = receive_getc;
857 lwr_receive_getbuf = receive_getbuf;
858 lwr_receive_hasc = receive_hasc;
859 lwr_receive_ungetc = receive_ungetc;
863 DEBUG(D_receive) debug_printf("chunking double-push receive functions\n");
866 receive_getc = bdat_getc;
867 receive_getbuf = bdat_getbuf;
868 receive_hasc = bdat_hasc;
869 receive_ungetc = bdat_ungetc;
873 bdat_pop_receive_functions(void)
875 if (!lwr_receive_getc)
877 DEBUG(D_receive) debug_printf("chunking double-pop receive functions\n");
880 receive_getc = lwr_receive_getc;
881 receive_getbuf = lwr_receive_getbuf;
882 receive_hasc = lwr_receive_hasc;
883 receive_ungetc = lwr_receive_ungetc;
885 lwr_receive_getc = NULL;
886 lwr_receive_getbuf = NULL;
887 lwr_receive_hasc = NULL;
888 lwr_receive_ungetc = NULL;
894 chunking_data_left++;
895 bdat_push_receive_functions(); /* we're not done yet, calling push is safe, because it checks the state before pushing anything */
896 return lwr_receive_ungetc(ch);
901 /******************************************************************************/
903 /*************************************************
904 * Write formatted string to SMTP channel *
905 *************************************************/
907 /* This is a separate function so that we don't have to repeat everything for
908 TLS support or debugging. It is global so that the daemon and the
909 authentication functions can use it. It does not return any error indication,
910 because major problems such as dropped connections won't show up till an output
911 flush for non-TLS connections. The smtp_fflush() function is available for
912 checking that: for convenience, TLS output errors are remembered here so that
913 they are also picked up later by smtp_fflush().
915 This function is exposed to the local_scan API; do not change the signature.
919 more further data expected
920 ... optional arguments
926 smtp_printf(const char *format, BOOL more, ...)
931 smtp_vprintf(format, more, ap);
935 /* This is split off so that verify.c:respond_printf() can, in effect, call
936 smtp_printf(), bearing in mind that in C a vararg function can't directly
937 call another vararg function, only a function which accepts a va_list.
939 This function is exposed to the local_scan API; do not change the signature.
941 /*XXX consider passing caller-info in, for string_vformat-onward */
944 smtp_vprintf(const char *format, BOOL more, va_list ap)
946 gstring gs = { .size = big_buffer_size, .ptr = 0, .s = big_buffer };
949 /* Use taint-unchecked routines for writing into big_buffer, trusting
950 that we'll never expand it. */
952 yield = !! string_vformat(&gs, SVFMT_TAINT_NOCHK, format, ap);
953 string_from_gstring(&gs);
955 DEBUG(D_receive) for (const uschar * t, * s = gs.s;
956 s && (t = Ustrchr(s, '\r'));
957 s = t + 2) /* \r\n */
958 debug_printf("%s %.*s\n",
959 s == gs.s ? "SMTP>>" : " ",
964 log_write(0, LOG_MAIN|LOG_PANIC, "string too large in smtp_printf()");
965 smtp_closedown(US"Unexpected error");
966 exim_exit(EXIT_FAILURE);
969 /* If this is the first output for a (non-batch) RCPT command, see if all RCPTs
970 have had the same. Note: this code is also present in smtp_respond(). It would
971 be tidier to have it only in one place, but when it was added, it was easier to
972 do it that way, so as not to have to mess with the code for the RCPT command,
973 which sometimes uses smtp_printf() and sometimes smtp_respond(). */
975 if (fl.rcpt_in_progress)
977 if (!rcpt_smtp_response)
978 rcpt_smtp_response = string_copy(big_buffer);
979 else if (fl.rcpt_smtp_response_same &&
980 Ustrcmp(rcpt_smtp_response, big_buffer) != 0)
981 fl.rcpt_smtp_response_same = FALSE;
982 fl.rcpt_in_progress = FALSE;
985 /* Now write the string */
989 tls_in.active.sock >= 0 ? (tls_write(NULL, gs.s, gs.ptr, more) < 0) :
991 (fwrite(gs.s, gs.ptr, 1, smtp_out) == 0)
993 smtp_write_error = -1;
998 /*************************************************
999 * Flush SMTP out and check for error *
1000 *************************************************/
1002 /* This function isn't currently used within Exim (it detects errors when it
1003 tries to read the next SMTP input), but is available for use in local_scan().
1004 It flushes the output and checks for errors.
1007 Returns: 0 for no error; -1 after an error
1013 if (tls_in.active.sock < 0 && fflush(smtp_out) != 0) smtp_write_error = -1;
1017 tls_in.active.sock >= 0 ? (tls_write(NULL, NULL, 0, FALSE) < 0) :
1019 (fflush(smtp_out) != 0)
1021 smtp_write_error = -1;
1023 return smtp_write_error;
1028 /* If there's input waiting (and we're doing pipelineing) then we can pipeline
1029 a reponse with the one following. */
1032 pipeline_response(void)
1034 if ( !smtp_enforce_sync || !sender_host_address
1035 || f.sender_host_notsocket || !f.smtp_in_pipelining_advertised)
1038 if (wouldblock_reading()) return FALSE;
1039 f.smtp_in_pipelining_used = TRUE;
1044 #ifndef DISABLE_PIPE_CONNECT
1046 pipeline_connect_sends(void)
1048 if (!sender_host_address || f.sender_host_notsocket || !fl.pipe_connect_acceptable)
1051 if (wouldblock_reading()) return FALSE;
1052 f.smtp_in_early_pipe_used = TRUE;
1057 /*************************************************
1058 * SMTP command read timeout *
1059 *************************************************/
1061 /* Signal handler for timing out incoming SMTP commands. This attempts to
1064 Argument: signal number (SIGALRM)
1069 command_timeout_handler(int sig)
1071 had_command_timeout = sig;
1076 /*************************************************
1077 * SIGTERM received *
1078 *************************************************/
1080 /* Signal handler for handling SIGTERM. Again, try to finish tidily.
1082 Argument: signal number (SIGTERM)
1087 command_sigterm_handler(int sig)
1089 had_command_sigterm = sig;
1095 #ifdef SUPPORT_PROXY
1096 /*************************************************
1097 * Check if host is required proxy host *
1098 *************************************************/
1099 /* The function determines if inbound host will be a regular smtp host
1100 or if it is configured that it must use Proxy Protocol. A local
1108 check_proxy_protocol_host()
1112 if ( sender_host_address
1113 && (rc = verify_check_this_host(CUSS &hosts_proxy, NULL, NULL,
1114 sender_host_address, NULL)) == OK)
1117 debug_printf("Detected proxy protocol configured host\n");
1118 proxy_session = TRUE;
1120 return proxy_session;
1124 /*************************************************
1125 * Read data until newline or end of buffer *
1126 *************************************************/
1127 /* While SMTP is server-speaks-first, TLS is client-speaks-first, so we can't
1128 read an entire buffer and assume there will be nothing past a proxy protocol
1129 header. Our approach normally is to use stdio, but again that relies upon
1130 "STARTTLS\r\n" and a server response before the client starts TLS handshake, or
1131 reading _nothing_ before client TLS handshake. So we don't want to use the
1132 usual buffering reads which may read enough to block TLS starting.
1134 So unfortunately we're down to "read one byte at a time, with a syscall each,
1135 and expect a little overhead", for all proxy-opened connections which are v1,
1136 just to handle the TLS-on-connect case. Since SSL functions wrap the
1137 underlying fd, we can't assume that we can feed them any already-read content.
1139 We need to know where to read to, the max capacity, and we'll read until we
1140 get a CR and one more character. Let the caller scream if it's CR+!LF.
1142 Return the amount read.
1146 swallow_until_crlf(int fd, uschar *base, int already, int capacity)
1148 uschar *to = base + already;
1154 /* For "PROXY UNKNOWN\r\n" we, at time of writing, expect to have read
1155 up through the \r; for the _normal_ case, we haven't yet seen the \r. */
1157 cr = memchr(base, '\r', already);
1160 if ((cr - base) < already - 1)
1162 /* \r and presumed \n already within what we have; probably not
1163 actually proxy protocol, but abort cleanly. */
1166 /* \r is last character read, just need one more. */
1170 while (capacity > 0)
1172 do { ret = read(fd, to, 1); } while (ret == -1 && errno == EINTR && !had_command_timeout);
1184 /* reached end without having room for a final newline, abort */
1189 /*************************************************
1190 * Setup host for proxy protocol *
1191 *************************************************/
1192 /* The function configures the connection based on a header from the
1193 inbound host to use Proxy Protocol. The specification is very exact
1194 so exit with an error if do not find the exact required pieces. This
1195 includes an incorrect number of spaces separating args.
1198 Returns: Boolean success
1202 setup_proxy_protocol_host()
1214 struct { /* TCP/UDP over IPv4, len = 12 */
1220 struct { /* TCP/UDP over IPv6, len = 36 */
1221 uint8_t src_addr[16];
1222 uint8_t dst_addr[16];
1226 struct { /* AF_UNIX sockets, len = 216 */
1227 uschar src_addr[108];
1228 uschar dst_addr[108];
1234 /* Temp variables used in PPv2 address:port parsing */
1236 char tmpip[INET_ADDRSTRLEN];
1237 struct sockaddr_in tmpaddr;
1238 char tmpip6[INET6_ADDRSTRLEN];
1239 struct sockaddr_in6 tmpaddr6;
1241 /* We can't read "all data until end" because while SMTP is
1242 server-speaks-first, the TLS handshake is client-speaks-first, so for
1243 TLS-on-connect ports the proxy protocol header will usually be immediately
1244 followed by a TLS handshake, and with N TLS libraries, we can't reliably
1245 reinject data for reading by those. So instead we first read "enough to be
1246 safely read within the header, and figure out how much more to read".
1247 For v1 we will later read to the end-of-line, for v2 we will read based upon
1250 The v2 sig is 12 octets, and another 4 gets us the length, so we know how much
1251 data is needed total. For v1, where the line looks like:
1252 PROXY TCPn L3src L3dest SrcPort DestPort \r\n
1254 However, for v1 there's also `PROXY UNKNOWN\r\n` which is only 15 octets.
1255 We seem to support that. So, if we read 14 octets then we can tell if we're
1256 v2 or v1. If we're v1, we can continue reading as normal.
1258 If we're v2, we can't slurp up the entire header. We need the length in the
1259 15th & 16th octets, then to read everything after that.
1261 So to safely handle v1 and v2, with client-sent-first supported correctly,
1262 we have to do a minimum of 3 read calls, not 1. Eww.
1265 #define PROXY_INITIAL_READ 14
1266 #define PROXY_V2_HEADER_SIZE 16
1267 #if PROXY_INITIAL_READ > PROXY_V2_HEADER_SIZE
1268 # error Code bug in sizes of data to read for proxy usage
1273 int fd = fileno(smtp_in);
1274 const char v2sig[12] = "\x0D\x0A\x0D\x0A\x00\x0D\x0A\x51\x55\x49\x54\x0A";
1275 uschar * iptype; /* To display debug info */
1276 socklen_t vslen = sizeof(struct timeval);
1279 os_non_restarting_signal(SIGALRM, command_timeout_handler);
1280 ALARM(proxy_protocol_timeout);
1284 /* The inbound host was declared to be a Proxy Protocol host, so
1285 don't do a PEEK into the data, actually slurp up enough to be
1286 "safe". Can't take it all because TLS-on-connect clients follow
1287 immediately with TLS handshake. */
1288 ret = read(fd, &hdr, PROXY_INITIAL_READ);
1290 while (ret == -1 && errno == EINTR && !had_command_timeout);
1295 /* For v2, handle reading the length, and then the rest. */
1296 if ((ret == PROXY_INITIAL_READ) && (memcmp(&hdr.v2, v2sig, sizeof(v2sig)) == 0))
1301 /* First get the length fields. */
1304 retmore = read(fd, (uschar*)&hdr + ret, PROXY_V2_HEADER_SIZE - PROXY_INITIAL_READ);
1305 } while (retmore == -1 && errno == EINTR && !had_command_timeout);
1310 ver = (hdr.v2.ver_cmd & 0xf0) >> 4;
1312 /* May 2014: haproxy combined the version and command into one byte to
1313 allow two full bytes for the length field in order to proxy SSL
1314 connections. SSL Proxy is not supported in this version of Exim, but
1315 must still separate values here. */
1319 DEBUG(D_receive) debug_printf("Invalid Proxy Protocol version: %d\n", ver);
1323 /* The v2 header will always be 16 bytes per the spec. */
1324 size = 16 + ntohs(hdr.v2.len);
1325 DEBUG(D_receive) debug_printf("Detected PROXYv2 header, size %d (limit %d)\n",
1326 size, (int)sizeof(hdr));
1328 /* We should now have 16 octets (PROXY_V2_HEADER_SIZE), and we know the total
1329 amount that we need. Double-check that the size is not unreasonable, then
1331 if (size > sizeof(hdr))
1333 DEBUG(D_receive) debug_printf("PROXYv2 header size unreasonably large; security attack?\n");
1341 retmore = read(fd, (uschar*)&hdr + ret, size-ret);
1342 } while (retmore == -1 && errno == EINTR && !had_command_timeout);
1346 DEBUG(D_receive) debug_printf("PROXYv2: have %d/%d required octets\n", ret, size);
1347 } while (ret < size);
1349 } /* end scope for getting rest of data for v2 */
1351 /* At this point: if PROXYv2, we've read the exact size required for all data;
1352 if PROXYv1 then we've read "less than required for any valid line" and should
1355 if (ret >= 16 && memcmp(&hdr.v2, v2sig, 12) == 0)
1357 uint8_t cmd = (hdr.v2.ver_cmd & 0x0f);
1361 case 0x01: /* PROXY command */
1364 case 0x11: /* TCPv4 address type */
1366 tmpaddr.sin_addr.s_addr = hdr.v2.addr.ip4.src_addr;
1367 inet_ntop(AF_INET, &tmpaddr.sin_addr, CS &tmpip, sizeof(tmpip));
1368 if (!string_is_ip_address(US tmpip, NULL))
1370 DEBUG(D_receive) debug_printf("Invalid %s source IP\n", iptype);
1373 proxy_local_address = sender_host_address;
1374 sender_host_address = string_copy(US tmpip);
1375 tmpport = ntohs(hdr.v2.addr.ip4.src_port);
1376 proxy_local_port = sender_host_port;
1377 sender_host_port = tmpport;
1378 /* Save dest ip/port */
1379 tmpaddr.sin_addr.s_addr = hdr.v2.addr.ip4.dst_addr;
1380 inet_ntop(AF_INET, &tmpaddr.sin_addr, CS &tmpip, sizeof(tmpip));
1381 if (!string_is_ip_address(US tmpip, NULL))
1383 DEBUG(D_receive) debug_printf("Invalid %s dest port\n", iptype);
1386 proxy_external_address = string_copy(US tmpip);
1387 tmpport = ntohs(hdr.v2.addr.ip4.dst_port);
1388 proxy_external_port = tmpport;
1390 case 0x21: /* TCPv6 address type */
1392 memmove(tmpaddr6.sin6_addr.s6_addr, hdr.v2.addr.ip6.src_addr, 16);
1393 inet_ntop(AF_INET6, &tmpaddr6.sin6_addr, CS &tmpip6, sizeof(tmpip6));
1394 if (!string_is_ip_address(US tmpip6, NULL))
1396 DEBUG(D_receive) debug_printf("Invalid %s source IP\n", iptype);
1399 proxy_local_address = sender_host_address;
1400 sender_host_address = string_copy(US tmpip6);
1401 tmpport = ntohs(hdr.v2.addr.ip6.src_port);
1402 proxy_local_port = sender_host_port;
1403 sender_host_port = tmpport;
1404 /* Save dest ip/port */
1405 memmove(tmpaddr6.sin6_addr.s6_addr, hdr.v2.addr.ip6.dst_addr, 16);
1406 inet_ntop(AF_INET6, &tmpaddr6.sin6_addr, CS &tmpip6, sizeof(tmpip6));
1407 if (!string_is_ip_address(US tmpip6, NULL))
1409 DEBUG(D_receive) debug_printf("Invalid %s dest port\n", iptype);
1412 proxy_external_address = string_copy(US tmpip6);
1413 tmpport = ntohs(hdr.v2.addr.ip6.dst_port);
1414 proxy_external_port = tmpport;
1418 debug_printf("Unsupported PROXYv2 connection type: 0x%02x\n",
1422 /* Unsupported protocol, keep local connection address */
1424 case 0x00: /* LOCAL command */
1425 /* Keep local connection address for LOCAL */
1430 debug_printf("Unsupported PROXYv2 command: 0x%x\n", cmd);
1434 else if (ret >= 8 && memcmp(hdr.v1.line, "PROXY", 5) == 0)
1438 uschar *sp; /* Utility variables follow */
1443 /* get the rest of the line */
1444 r2 = swallow_until_crlf(fd, (uschar*)&hdr, ret, sizeof(hdr)-ret);
1449 p = string_copy(hdr.v1.line);
1450 end = memchr(p, '\r', ret - 1);
1452 if (!end || (end == (uschar*)&hdr + ret) || end[1] != '\n')
1454 DEBUG(D_receive) debug_printf("Partial or invalid PROXY header\n");
1457 *end = '\0'; /* Terminate the string */
1458 size = end + 2 - p; /* Skip header + CRLF */
1459 DEBUG(D_receive) debug_printf("Detected PROXYv1 header\n");
1460 DEBUG(D_receive) debug_printf("Bytes read not within PROXY header: %d\n", ret - size);
1461 /* Step through the string looking for the required fields. Ensure
1462 strict adherence to required formatting, exit for any error. */
1464 if (!isspace(*(p++)))
1466 DEBUG(D_receive) debug_printf("Missing space after PROXY command\n");
1469 if (!Ustrncmp(p, CCS"TCP4", 4))
1471 else if (!Ustrncmp(p,CCS"TCP6", 4))
1473 else if (!Ustrncmp(p,CCS"UNKNOWN", 7))
1475 iptype = US"Unknown";
1480 DEBUG(D_receive) debug_printf("Invalid TCP type\n");
1484 p += Ustrlen(iptype);
1485 if (!isspace(*(p++)))
1487 DEBUG(D_receive) debug_printf("Missing space after TCP4/6 command\n");
1490 /* Find the end of the arg */
1491 if ((sp = Ustrchr(p, ' ')) == NULL)
1494 debug_printf("Did not find proxied src %s\n", iptype);
1498 if(!string_is_ip_address(p, NULL))
1501 debug_printf("Proxied src arg is not an %s address\n", iptype);
1504 proxy_local_address = sender_host_address;
1505 sender_host_address = p;
1507 if ((sp = Ustrchr(p, ' ')) == NULL)
1510 debug_printf("Did not find proxy dest %s\n", iptype);
1514 if(!string_is_ip_address(p, NULL))
1517 debug_printf("Proxy dest arg is not an %s address\n", iptype);
1520 proxy_external_address = p;
1522 if ((sp = Ustrchr(p, ' ')) == NULL)
1524 DEBUG(D_receive) debug_printf("Did not find proxied src port\n");
1528 tmp_port = strtol(CCS p, &endc, 10);
1529 if (*endc || tmp_port == 0)
1532 debug_printf("Proxied src port '%s' not an integer\n", p);
1535 proxy_local_port = sender_host_port;
1536 sender_host_port = tmp_port;
1538 if ((sp = Ustrchr(p, '\0')) == NULL)
1540 DEBUG(D_receive) debug_printf("Did not find proxy dest port\n");
1543 tmp_port = strtol(CCS p, &endc, 10);
1544 if (*endc || tmp_port == 0)
1547 debug_printf("Proxy dest port '%s' not an integer\n", p);
1550 proxy_external_port = tmp_port;
1551 /* Already checked for /r /n above. Good V1 header received. */
1555 /* Wrong protocol */
1556 DEBUG(D_receive) debug_printf("Invalid proxy protocol version negotiation\n");
1557 (void) swallow_until_crlf(fd, (uschar*)&hdr, ret, sizeof(hdr)-ret);
1563 debug_printf("Valid %s sender from Proxy Protocol header\n", iptype);
1564 yield = proxy_session;
1566 /* Don't flush any potential buffer contents. Any input on proxyfail
1567 should cause a synchronization failure */
1570 DEBUG(D_receive) if (had_command_timeout)
1571 debug_printf("Timeout while reading proxy header\n");
1576 sender_host_name = NULL;
1577 (void) host_name_lookup();
1578 host_build_sender_fullhost();
1582 f.proxy_session_failed = TRUE;
1584 debug_printf("Failure to extract proxied host, only QUIT allowed\n");
1592 /*************************************************
1593 * Read one command line *
1594 *************************************************/
1596 /* Strictly, SMTP commands coming over the net are supposed to end with CRLF.
1597 There are sites that don't do this, and in any case internal SMTP probably
1598 should check only for LF. Consequently, we check here for LF only. The line
1599 ends up with [CR]LF removed from its end. If we get an overlong line, treat as
1600 an unknown command. The command is read into the global smtp_cmd_buffer so that
1601 it is available via $smtp_command.
1603 The character reading routine sets up a timeout for each block actually read
1604 from the input (which may contain more than one command). We set up a special
1605 signal handler that closes down the session on a timeout. Control does not
1606 return when it runs.
1609 check_sync if TRUE, check synchronization rules if global option is TRUE
1610 buffer_lim maximum to buffer in lower layer
1612 Returns: a code identifying the command (enumerated above)
1616 smtp_read_command(BOOL check_sync, unsigned buffer_lim)
1620 BOOL hadnull = FALSE;
1622 had_command_timeout = 0;
1623 os_non_restarting_signal(SIGALRM, command_timeout_handler);
1625 while ((c = (receive_getc)(buffer_lim)) != '\n' && c != EOF)
1627 if (ptr >= SMTP_CMD_BUFFER_SIZE)
1629 os_non_restarting_signal(SIGALRM, sigalrm_handler);
1637 smtp_cmd_buffer[ptr++] = c;
1640 receive_linecount++; /* For BSMTP errors */
1641 os_non_restarting_signal(SIGALRM, sigalrm_handler);
1643 /* If hit end of file, return pseudo EOF command. Whether we have a
1644 part-line already read doesn't matter, since this is an error state. */
1646 if (c == EOF) return EOF_CMD;
1648 /* Remove any CR and white space at the end of the line, and terminate the
1651 while (ptr > 0 && isspace(smtp_cmd_buffer[ptr-1])) ptr--;
1652 smtp_cmd_buffer[ptr] = 0;
1654 DEBUG(D_receive) debug_printf("SMTP<< %s\n", smtp_cmd_buffer);
1656 /* NULLs are not allowed in SMTP commands */
1658 if (hadnull) return BADCHAR_CMD;
1660 /* Scan command list and return identity, having set the data pointer
1661 to the start of the actual data characters. Check for SMTP synchronization
1664 for (smtp_cmd_list * p = cmd_list; p < cmd_list_end; p++)
1666 #ifdef SUPPORT_PROXY
1667 /* Only allow QUIT command if Proxy Protocol parsing failed */
1668 if (proxy_session && f.proxy_session_failed && p->cmd != QUIT_CMD)
1672 && strncmpic(smtp_cmd_buffer, US p->name, p->len) == 0
1673 && ( smtp_cmd_buffer[p->len-1] == ':' /* "mail from:" or "rcpt to:" */
1674 || smtp_cmd_buffer[p->len] == 0
1675 || smtp_cmd_buffer[p->len] == ' '
1678 if ( smtp_inptr < smtp_inend /* Outstanding input */
1679 && p->cmd < sync_cmd_limit /* Command should sync */
1680 && check_sync /* Local flag set */
1681 && smtp_enforce_sync /* Global flag set */
1682 && sender_host_address != NULL /* Not local input */
1683 && !f.sender_host_notsocket /* Really is a socket */
1687 /* The variables $smtp_command and $smtp_command_argument point into the
1688 unmodified input buffer. A copy of the latter is taken for actual
1689 processing, so that it can be chopped up into separate parts if necessary,
1690 for example, when processing a MAIL command options such as SIZE that can
1691 follow the sender address. */
1693 smtp_cmd_argument = smtp_cmd_buffer + p->len;
1694 while (isspace(*smtp_cmd_argument)) smtp_cmd_argument++;
1695 Ustrcpy(smtp_data_buffer, smtp_cmd_argument);
1696 smtp_cmd_data = smtp_data_buffer;
1698 /* Count non-mail commands from those hosts that are controlled in this
1699 way. The default is all hosts. We don't waste effort checking the list
1700 until we get a non-mail command, but then cache the result to save checking
1701 again. If there's a DEFER while checking the host, assume it's in the list.
1703 Note that one instance of RSET, EHLO/HELO, and STARTTLS is allowed at the
1704 start of each incoming message by fiddling with the value in the table. */
1706 if (!p->is_mail_cmd)
1708 if (count_nonmail == TRUE_UNSET) count_nonmail =
1709 verify_check_host(&smtp_accept_max_nonmail_hosts) != FAIL;
1710 if (count_nonmail && ++nonmail_command_count > smtp_accept_max_nonmail)
1711 return TOO_MANY_NONMAIL_CMD;
1714 /* If there is data for a command that does not expect it, generate the
1717 return (p->has_arg || *smtp_cmd_data == 0)? p->cmd : BADARG_CMD;
1721 #ifdef SUPPORT_PROXY
1722 /* Only allow QUIT command if Proxy Protocol parsing failed */
1723 if (proxy_session && f.proxy_session_failed)
1724 return PROXY_FAIL_IGNORE_CMD;
1727 /* Enforce synchronization for unknown commands */
1729 if ( smtp_inptr < smtp_inend /* Outstanding input */
1730 && check_sync /* Local flag set */
1731 && smtp_enforce_sync /* Global flag set */
1732 && sender_host_address /* Not local input */
1733 && !f.sender_host_notsocket /* Really is a socket */
1742 /*************************************************
1743 * Forced closedown of call *
1744 *************************************************/
1746 /* This function is called from log.c when Exim is dying because of a serious
1747 disaster, and also from some other places. If an incoming non-batched SMTP
1748 channel is open, it swallows the rest of the incoming message if in the DATA
1749 phase, sends the reply string, and gives an error to all subsequent commands
1750 except QUIT. The existence of an SMTP call is detected by the non-NULLness of
1754 message SMTP reply string to send, excluding the code
1760 smtp_closedown(uschar * message)
1762 if (!smtp_in || smtp_batched_input) return;
1763 receive_swallow_smtp();
1764 smtp_printf("421 %s\r\n", FALSE, message);
1766 for (;;) switch(smtp_read_command(FALSE, GETC_BUFFER_UNLIMITED))
1772 f.smtp_in_quit = TRUE;
1773 smtp_printf("221 %s closing connection\r\n", FALSE, smtp_active_hostname);
1778 smtp_printf("250 Reset OK\r\n", FALSE);
1782 smtp_printf("421 %s\r\n", FALSE, message);
1790 /*************************************************
1791 * Set up connection info for logging *
1792 *************************************************/
1794 /* This function is called when logging information about an SMTP connection.
1795 It sets up appropriate source information, depending on the type of connection.
1796 If sender_fullhost is NULL, we are at a very early stage of the connection;
1797 just use the IP address.
1800 Returns: a string describing the connection
1804 smtp_get_connection_info(void)
1806 const uschar * hostname = sender_fullhost
1807 ? sender_fullhost : sender_host_address;
1810 return string_sprintf("SMTP connection from %s", hostname);
1812 if (f.sender_host_unknown || f.sender_host_notsocket)
1813 return string_sprintf("SMTP connection from %s", sender_ident);
1816 return string_sprintf("SMTP connection from %s (via inetd)", hostname);
1818 if (LOGGING(incoming_interface) && interface_address)
1819 return string_sprintf("SMTP connection from %s I=[%s]:%d", hostname,
1820 interface_address, interface_port);
1822 return string_sprintf("SMTP connection from %s", hostname);
1828 /* Append TLS-related information to a log line
1831 g String under construction: allocated string to extend, or NULL
1833 Returns: Allocated string or NULL
1836 s_tlslog(gstring * g)
1838 if (LOGGING(tls_cipher) && tls_in.cipher)
1840 g = string_append(g, 2, US" X=", tls_in.cipher);
1841 #ifndef DISABLE_TLS_RESUME
1842 if (LOGGING(tls_resumption) && tls_in.resumption & RESUME_USED)
1843 g = string_catn(g, US"*", 1);
1846 if (LOGGING(tls_certificate_verified) && tls_in.cipher)
1847 g = string_append(g, 2, US" CV=", tls_in.certificate_verified? "yes":"no");
1848 if (LOGGING(tls_peerdn) && tls_in.peerdn)
1849 g = string_append(g, 3, US" DN=\"", string_printing(tls_in.peerdn), US"\"");
1850 if (LOGGING(tls_sni) && tls_in.sni)
1851 g = string_append(g, 2, US" SNI=", string_printing2(tls_in.sni, SP_TAB|SP_SPACE));
1859 s_connhad_log(gstring * g)
1861 const uschar * sep = smtp_connection_had[SMTP_HBUFF_SIZE-1] != SCH_NONE
1862 ? US" C=..." : US" C=";
1864 for (int i = smtp_ch_index; i < SMTP_HBUFF_SIZE; i++)
1865 if (smtp_connection_had[i] != SCH_NONE)
1867 g = string_append(g, 2, sep, smtp_names[smtp_connection_had[i]]);
1870 for (int i = 0; i < smtp_ch_index; i++, sep = US",")
1871 g = string_append(g, 2, sep, smtp_names[smtp_connection_had[i]]);
1876 /*************************************************
1877 * Log lack of MAIL if so configured *
1878 *************************************************/
1880 /* This function is called when an SMTP session ends. If the log selector
1881 smtp_no_mail is set, write a log line giving some details of what has happened
1882 in the SMTP session.
1889 smtp_log_no_mail(void)
1894 if (smtp_mailcmd_count > 0 || !LOGGING(smtp_no_mail))
1897 if (sender_host_authenticated)
1899 g = string_append(g, 2, US" A=", sender_host_authenticated);
1900 if (authenticated_id) g = string_append(g, 2, US":", authenticated_id);
1907 g = s_connhad_log(g);
1909 if (!(s = string_from_gstring(g))) s = US"";
1911 log_write(0, LOG_MAIN, "no MAIL in %sSMTP connection from %s D=%s%s",
1912 f.tcp_in_fastopen ? f.tcp_in_fastopen_data ? US"TFO* " : US"TFO " : US"",
1913 host_and_ident(FALSE), string_timesince(&smtp_connection_start), s);
1917 /* Return list of recent smtp commands */
1922 gstring * list = NULL;
1925 for (int i = smtp_ch_index; i < SMTP_HBUFF_SIZE; i++)
1926 if (smtp_connection_had[i] != SCH_NONE)
1927 list = string_append_listele(list, ',', smtp_names[smtp_connection_had[i]]);
1929 for (int i = 0; i < smtp_ch_index; i++)
1930 list = string_append_listele(list, ',', smtp_names[smtp_connection_had[i]]);
1932 s = string_from_gstring(list);
1933 return s ? s : US"";
1939 /*************************************************
1940 * Check HELO line and set sender_helo_name *
1941 *************************************************/
1943 /* Check the format of a HELO line. The data for HELO/EHLO is supposed to be
1944 the domain name of the sending host, or an ip literal in square brackets. The
1945 argument is placed in sender_helo_name, which is in malloc store, because it
1946 must persist over multiple incoming messages. If helo_accept_junk is set, this
1947 host is permitted to send any old junk (needed for some broken hosts).
1948 Otherwise, helo_allow_chars can be used for rogue characters in general
1949 (typically people want to let in underscores).
1952 s the data portion of the line (already past any white space)
1954 Returns: TRUE or FALSE
1958 check_helo(uschar *s)
1961 uschar *end = s + Ustrlen(s);
1962 BOOL yield = fl.helo_accept_junk;
1964 /* Discard any previous helo name */
1966 sender_helo_name = NULL;
1968 /* Skip tests if junk is permitted. */
1972 /* Allow the new standard form for IPv6 address literals, namely,
1973 [IPv6:....], and because someone is bound to use it, allow an equivalent
1974 IPv4 form. Allow plain addresses as well. */
1981 if (strncmpic(s, US"[IPv6:", 6) == 0)
1982 yield = (string_is_ip_address(s+6, NULL) == 6);
1983 else if (strncmpic(s, US"[IPv4:", 6) == 0)
1984 yield = (string_is_ip_address(s+6, NULL) == 4);
1986 yield = (string_is_ip_address(s+1, NULL) != 0);
1991 /* Non-literals must be alpha, dot, hyphen, plus any non-valid chars
1992 that have been configured (usually underscore - sigh). */
1995 for (yield = TRUE; *s; s++)
1996 if (!isalnum(*s) && *s != '.' && *s != '-' &&
1997 Ustrchr(helo_allow_chars, *s) == NULL)
2003 /* Save argument if OK */
2005 if (yield) sender_helo_name = string_copy_perm(start, TRUE);
2013 /*************************************************
2014 * Extract SMTP command option *
2015 *************************************************/
2017 /* This function picks the next option setting off the end of smtp_cmd_data. It
2018 is called for MAIL FROM and RCPT TO commands, to pick off the optional ESMTP
2019 things that can appear there.
2022 name point this at the name
2023 value point this at the data string
2025 Returns: TRUE if found an option
2029 extract_option(uschar **name, uschar **value)
2033 if (Ustrlen(smtp_cmd_data) <= 0) return FALSE;
2034 v = smtp_cmd_data + Ustrlen(smtp_cmd_data) - 1;
2035 while (v > smtp_cmd_data && isspace(*v)) v--;
2038 while (v > smtp_cmd_data && *v != '=' && !isspace(*v))
2040 /* Take care to not stop at a space embedded in a quoted local-part */
2043 do v--; while (v > smtp_cmd_data && *v != '"');
2044 if (v <= smtp_cmd_data) return FALSE;
2048 if (v <= smtp_cmd_data) return FALSE;
2053 while (n > smtp_cmd_data && isalpha(n[-1])) n--;
2054 /* RFC says SP, but TAB seen in wild and other major MTAs accept it */
2055 if (n <= smtp_cmd_data || !isspace(n[-1])) return FALSE;
2072 /*************************************************
2073 * Reset for new message *
2074 *************************************************/
2076 /* This function is called whenever the SMTP session is reset from
2077 within either of the setup functions; also from the daemon loop.
2079 Argument: the stacking pool storage reset point
2084 smtp_reset(void *reset_point)
2086 recipients_list = NULL;
2087 rcpt_count = rcpt_defer_count = rcpt_fail_count =
2088 raw_recipients_count = recipients_count = recipients_list_max = 0;
2089 message_linecount = 0;
2091 message_body = message_body_end = NULL;
2092 acl_added_headers = NULL;
2093 acl_removed_headers = NULL;
2094 f.queue_only_policy = FALSE;
2095 rcpt_smtp_response = NULL;
2096 fl.rcpt_smtp_response_same = TRUE;
2097 fl.rcpt_in_progress = FALSE;
2098 f.deliver_freeze = FALSE; /* Can be set by ACL */
2099 freeze_tell = freeze_tell_config; /* Can be set by ACL */
2100 fake_response = OK; /* Can be set by ACL */
2101 #ifdef WITH_CONTENT_SCAN
2102 f.no_mbox_unspool = FALSE; /* Can be set by ACL */
2104 f.submission_mode = FALSE; /* Can be set by ACL */
2105 f.suppress_local_fixups = f.suppress_local_fixups_default; /* Can be set by ACL */
2106 f.active_local_from_check = local_from_check; /* Can be set by ACL */
2107 f.active_local_sender_retain = local_sender_retain; /* Can be set by ACL */
2108 sending_ip_address = NULL;
2109 return_path = sender_address = NULL;
2110 deliver_localpart_data = deliver_domain_data =
2111 recipient_data = sender_data = NULL; /* Can be set by ACL */
2112 recipient_verify_failure = NULL;
2113 deliver_localpart_parent = deliver_localpart_orig = NULL;
2114 deliver_domain_parent = deliver_domain_orig = NULL;
2115 callout_address = NULL;
2116 submission_name = NULL; /* Can be set by ACL */
2117 raw_sender = NULL; /* After SMTP rewrite, before qualifying */
2118 sender_address_unrewritten = NULL; /* Set only after verify rewrite */
2119 sender_verified_list = NULL; /* No senders verified */
2120 memset(sender_address_cache, 0, sizeof(sender_address_cache));
2121 memset(sender_domain_cache, 0, sizeof(sender_domain_cache));
2123 authenticated_sender = NULL;
2124 #ifdef EXPERIMENTAL_BRIGHTMAIL
2126 bmi_verdicts = NULL;
2128 dnslist_domain = dnslist_matched = NULL;
2130 spf_header_comment = spf_received = spf_result = spf_smtp_comment = NULL;
2131 spf_result_guessed = FALSE;
2133 #ifndef DISABLE_DKIM
2134 dkim_cur_signer = dkim_signers =
2135 dkim_signing_domain = dkim_signing_selector = dkim_signatures = NULL;
2136 dkim_cur_signer = dkim_signers = dkim_signing_domain = dkim_signing_selector = NULL;
2137 f.dkim_disable_verify = FALSE;
2138 dkim_collect_input = 0;
2139 dkim_verify_overall = dkim_verify_status = dkim_verify_reason = NULL;
2140 dkim_key_length = 0;
2142 #ifdef SUPPORT_DMARC
2143 f.dmarc_has_been_checked = f.dmarc_disable_verify = f.dmarc_enable_forensic = FALSE;
2144 dmarc_domain_policy = dmarc_status = dmarc_status_text =
2145 dmarc_used_domain = NULL;
2147 #ifdef EXPERIMENTAL_ARC
2148 arc_state = arc_state_reason = NULL;
2149 arc_received_instance = 0;
2153 deliver_host = deliver_host_address = NULL; /* Can be set by ACL */
2154 #ifndef DISABLE_PRDR
2155 prdr_requested = FALSE;
2158 message_smtputf8 = FALSE;
2160 #ifdef WITH_CONTENT_SCAN
2163 body_linecount = body_zerocount = 0;
2165 lookup_value = NULL; /* Can be set by ACL */
2166 sender_rate = sender_rate_limit = sender_rate_period = NULL;
2167 ratelimiters_mail = NULL; /* Updated by ratelimit ACL condition */
2168 /* Note that ratelimiters_conn persists across resets. */
2170 /* Reset message ACL variables */
2174 /* Warning log messages are saved in malloc store. They are saved to avoid
2175 repetition in the same message, but it seems right to repeat them for different
2178 while (acl_warn_logged)
2180 string_item *this = acl_warn_logged;
2181 acl_warn_logged = acl_warn_logged->next;
2186 store_reset(reset_point);
2189 return store_mark();
2196 /*************************************************
2197 * Initialize for incoming batched SMTP message *
2198 *************************************************/
2200 /* This function is called from smtp_setup_msg() in the case when
2201 smtp_batched_input is true. This happens when -bS is used to pass a whole batch
2202 of messages in one file with SMTP commands between them. All errors must be
2203 reported by sending a message, and only MAIL FROM, RCPT TO, and DATA are
2204 relevant. After an error on a sender, or an invalid recipient, the remainder
2205 of the message is skipped. The value of received_protocol is already set.
2208 Returns: > 0 message successfully started (reached DATA)
2209 = 0 QUIT read or end of file reached
2210 < 0 should not occur
2214 smtp_setup_batch_msg(void)
2217 rmark reset_point = store_mark();
2219 /* Save the line count at the start of each transaction - single commands
2220 like HELO and RSET count as whole transactions. */
2222 bsmtp_transaction_linecount = receive_linecount;
2224 if ((receive_feof)()) return 0; /* Treat EOF as QUIT */
2226 cancel_cutthrough_connection(TRUE, US"smtp_setup_batch_msg");
2227 reset_point = smtp_reset(reset_point); /* Reset for start of message */
2229 /* Deal with SMTP commands. This loop is exited by setting done to a POSITIVE
2230 value. The values are 2 larger than the required yield of the function. */
2235 uschar *recipient = NULL;
2236 int start, end, sender_domain, recipient_domain;
2238 switch(smtp_read_command(FALSE, GETC_BUFFER_UNLIMITED))
2240 /* The HELO/EHLO commands set sender_address_helo if they have
2241 valid data; otherwise they are ignored, except that they do
2242 a reset of the state. */
2247 check_helo(smtp_cmd_data);
2251 cancel_cutthrough_connection(TRUE, US"RSET received");
2252 reset_point = smtp_reset(reset_point);
2253 bsmtp_transaction_linecount = receive_linecount;
2257 /* The MAIL FROM command requires an address as an operand. All we
2258 do here is to parse it for syntactic correctness. The form "<>" is
2259 a special case which converts into an empty string. The start/end
2260 pointers in the original are not used further for this address, as
2261 it is the canonical extracted address which is all that is kept. */
2264 smtp_mailcmd_count++; /* Count for no-mail log */
2266 /* The function moan_smtp_batch() does not return. */
2267 moan_smtp_batch(smtp_cmd_buffer, "503 Sender already given");
2269 if (smtp_cmd_data[0] == 0)
2270 /* The function moan_smtp_batch() does not return. */
2271 moan_smtp_batch(smtp_cmd_buffer, "501 MAIL FROM must have an address operand");
2273 /* Reset to start of message */
2275 cancel_cutthrough_connection(TRUE, US"MAIL received");
2276 reset_point = smtp_reset(reset_point);
2278 /* Apply SMTP rewrite */
2280 raw_sender = rewrite_existflags & rewrite_smtp
2281 /* deconst ok as smtp_cmd_data was not const */
2282 ? US rewrite_one(smtp_cmd_data, rewrite_smtp|rewrite_smtp_sender, NULL,
2283 FALSE, US"", global_rewrite_rules)
2286 /* Extract the address; the TRUE flag allows <> as valid */
2289 parse_extract_address(raw_sender, &errmess, &start, &end, &sender_domain,
2293 /* The function moan_smtp_batch() does not return. */
2294 moan_smtp_batch(smtp_cmd_buffer, "501 %s", errmess);
2296 sender_address = string_copy(raw_sender);
2298 /* Qualify unqualified sender addresses if permitted to do so. */
2301 && sender_address[0] != 0 && sender_address[0] != '@')
2302 if (f.allow_unqualified_sender)
2304 /* deconst ok as sender_address was not const */
2305 sender_address = US rewrite_address_qualify(sender_address, FALSE);
2306 DEBUG(D_receive) debug_printf("unqualified address %s accepted "
2307 "and rewritten\n", raw_sender);
2309 /* The function moan_smtp_batch() does not return. */
2311 moan_smtp_batch(smtp_cmd_buffer, "501 sender address must contain "
2316 /* The RCPT TO command requires an address as an operand. All we do
2317 here is to parse it for syntactic correctness. There may be any number
2318 of RCPT TO commands, specifying multiple senders. We build them all into
2319 a data structure that is in argc/argv format. The start/end values
2320 given by parse_extract_address are not used, as we keep only the
2321 extracted address. */
2324 if (!sender_address)
2325 /* The function moan_smtp_batch() does not return. */
2326 moan_smtp_batch(smtp_cmd_buffer, "503 No sender yet given");
2328 if (smtp_cmd_data[0] == 0)
2329 /* The function moan_smtp_batch() does not return. */
2330 moan_smtp_batch(smtp_cmd_buffer,
2331 "501 RCPT TO must have an address operand");
2333 /* Check maximum number allowed */
2335 if (recipients_max > 0 && recipients_count + 1 > recipients_max)
2336 /* The function moan_smtp_batch() does not return. */
2337 moan_smtp_batch(smtp_cmd_buffer, "%s too many recipients",
2338 recipients_max_reject? "552": "452");
2340 /* Apply SMTP rewrite, then extract address. Don't allow "<>" as a
2341 recipient address */
2343 recipient = rewrite_existflags & rewrite_smtp
2344 /* deconst ok as smtp_cmd_data was not const */
2345 ? US rewrite_one(smtp_cmd_data, rewrite_smtp, NULL, FALSE, US"",
2346 global_rewrite_rules)
2349 recipient = parse_extract_address(recipient, &errmess, &start, &end,
2350 &recipient_domain, FALSE);
2353 /* The function moan_smtp_batch() does not return. */
2354 moan_smtp_batch(smtp_cmd_buffer, "501 %s", errmess);
2356 /* If the recipient address is unqualified, qualify it if permitted. Then
2357 add it to the list of recipients. */
2359 if (!recipient_domain)
2360 if (f.allow_unqualified_recipient)
2362 DEBUG(D_receive) debug_printf("unqualified address %s accepted\n",
2364 /* deconst ok as recipient was not const */
2365 recipient = US rewrite_address_qualify(recipient, TRUE);
2367 /* The function moan_smtp_batch() does not return. */
2369 moan_smtp_batch(smtp_cmd_buffer,
2370 "501 recipient address must contain a domain");
2372 receive_add_recipient(recipient, -1);
2376 /* The DATA command is legal only if it follows successful MAIL FROM
2377 and RCPT TO commands. This function is complete when a valid DATA
2378 command is encountered. */
2381 if (!sender_address || recipients_count <= 0)
2382 /* The function moan_smtp_batch() does not return. */
2383 if (!sender_address)
2384 moan_smtp_batch(smtp_cmd_buffer,
2385 "503 MAIL FROM:<sender> command must precede DATA");
2387 moan_smtp_batch(smtp_cmd_buffer,
2388 "503 RCPT TO:<recipient> must precede DATA");
2391 done = 3; /* DATA successfully achieved */
2392 message_ended = END_NOTENDED; /* Indicate in middle of message */
2397 /* The VRFY, EXPN, HELP, ETRN, and NOOP commands are ignored. */
2404 bsmtp_transaction_linecount = receive_linecount;
2409 f.smtp_in_quit = TRUE;
2416 /* The function moan_smtp_batch() does not return. */
2417 moan_smtp_batch(smtp_cmd_buffer, "501 Unexpected argument data");
2422 /* The function moan_smtp_batch() does not return. */
2423 moan_smtp_batch(smtp_cmd_buffer, "501 Unexpected NULL in SMTP command");
2428 /* The function moan_smtp_batch() does not return. */
2429 moan_smtp_batch(smtp_cmd_buffer, "500 Command unrecognized");
2434 return done - 2; /* Convert yield values */
2442 smtp_log_tls_fail(const uschar * errstr)
2444 const uschar * conn_info = smtp_get_connection_info();
2446 if (Ustrncmp(conn_info, US"SMTP ", 5) == 0) conn_info += 5;
2447 /* I'd like to get separated H= here, but too hard for now */
2449 log_write(0, LOG_MAIN, "TLS error on %s %s", conn_info, errstr);
2463 socklen_t len = sizeof(is_fastopen);
2465 /* The tinfo TCPOPT_FAST_OPEN bit seems unreliable, and we don't see state
2466 TCP_SYN_RCV (as of 12.1) so no idea about data-use. */
2468 if (getsockopt(fileno(smtp_out), IPPROTO_TCP, TCP_FASTOPEN, &is_fastopen, &len) == 0)
2473 debug_printf("TFO mode connection (TCP_FASTOPEN getsockopt)\n");
2474 f.tcp_in_fastopen = TRUE;
2477 else DEBUG(D_receive)
2478 debug_printf("TCP_INFO getsockopt: %s\n", strerror(errno));
2480 # elif defined(TCP_INFO)
2481 struct tcp_info tinfo;
2482 socklen_t len = sizeof(tinfo);
2484 if (getsockopt(fileno(smtp_out), IPPROTO_TCP, TCP_INFO, &tinfo, &len) == 0)
2485 # ifdef TCPI_OPT_SYN_DATA /* FreeBSD 11,12 do not seem to have this yet */
2486 if (tinfo.tcpi_options & TCPI_OPT_SYN_DATA)
2489 debug_printf("TFO mode connection (ACKd data-on-SYN)\n");
2490 f.tcp_in_fastopen_data = f.tcp_in_fastopen = TRUE;
2494 if (tinfo.tcpi_state == TCP_SYN_RECV) /* Not seen on FreeBSD 12.1 */
2497 debug_printf("TFO mode connection (state TCP_SYN_RECV)\n");
2498 f.tcp_in_fastopen = TRUE;
2500 else DEBUG(D_receive)
2501 debug_printf("TCP_INFO getsockopt: %s\n", strerror(errno));
2507 /*************************************************
2508 * Start an SMTP session *
2509 *************************************************/
2511 /* This function is called at the start of an SMTP session. Thereafter,
2512 smtp_setup_msg() is called to initiate each separate message. This
2513 function does host-specific testing, and outputs the banner line.
2516 Returns: FALSE if the session can not continue; something has
2517 gone wrong, or the connection to the host is blocked
2521 smtp_start_session(void)
2524 uschar *user_msg, *log_msg;
2529 gettimeofday(&smtp_connection_start, NULL);
2530 for (smtp_ch_index = 0; smtp_ch_index < SMTP_HBUFF_SIZE; smtp_ch_index++)
2531 smtp_connection_had[smtp_ch_index] = SCH_NONE;
2534 /* Default values for certain variables */
2536 fl.helo_seen = fl.esmtp = fl.helo_accept_junk = FALSE;
2537 smtp_mailcmd_count = 0;
2538 count_nonmail = TRUE_UNSET;
2539 synprot_error_count = unknown_command_count = nonmail_command_count = 0;
2540 smtp_delay_mail = smtp_rlm_base;
2541 fl.auth_advertised = FALSE;
2542 f.smtp_in_pipelining_advertised = f.smtp_in_pipelining_used = FALSE;
2543 f.pipelining_enable = TRUE;
2544 sync_cmd_limit = NON_SYNC_CMD_NON_PIPELINING;
2545 fl.smtp_exit_function_called = FALSE; /* For avoiding loop in not-quit exit */
2547 /* If receiving by -bs from a trusted user, or testing with -bh, we allow
2548 authentication settings from -oMaa to remain in force. */
2550 if (!host_checking && !f.sender_host_notsocket)
2551 sender_host_auth_pubname = sender_host_authenticated = NULL;
2552 authenticated_by = NULL;
2555 tls_in.ver = tls_in.cipher = tls_in.peerdn = NULL;
2556 tls_in.ourcert = tls_in.peercert = NULL;
2558 tls_in.ocsp = OCSP_NOT_REQ;
2559 fl.tls_advertised = FALSE;
2561 fl.dsn_advertised = FALSE;
2563 fl.smtputf8_advertised = FALSE;
2566 /* Reset ACL connection variables */
2570 /* Allow for trailing 0 in the command and data buffers. Tainted. */
2572 smtp_cmd_buffer = store_get_perm(2*SMTP_CMD_BUFFER_SIZE + 2, GET_TAINTED);
2574 smtp_cmd_buffer[0] = 0;
2575 smtp_data_buffer = smtp_cmd_buffer + SMTP_CMD_BUFFER_SIZE + 1;
2577 /* For batched input, the protocol setting can be overridden from the
2578 command line by a trusted caller. */
2580 if (smtp_batched_input)
2582 if (!received_protocol) received_protocol = US"local-bsmtp";
2585 /* For non-batched SMTP input, the protocol setting is forced here. It will be
2586 reset later if any of EHLO/AUTH/STARTTLS are received. */
2590 (sender_host_address ? protocols : protocols_local) [pnormal];
2592 /* Set up the buffer for inputting using direct read() calls, and arrange to
2593 call the local functions instead of the standard C ones. */
2597 receive_getc = smtp_getc;
2598 receive_getbuf = smtp_getbuf;
2599 receive_get_cache = smtp_get_cache;
2600 receive_hasc = smtp_hasc;
2601 receive_ungetc = smtp_ungetc;
2602 receive_feof = smtp_feof;
2603 receive_ferror = smtp_ferror;
2604 lwr_receive_getc = NULL;
2605 lwr_receive_getbuf = NULL;
2606 lwr_receive_hasc = NULL;
2607 lwr_receive_ungetc = NULL;
2609 /* Set up the message size limit; this may be host-specific */
2611 thismessage_size_limit = expand_string_integer(message_size_limit, TRUE);
2612 if (expand_string_message)
2614 if (thismessage_size_limit == -1)
2615 log_write(0, LOG_MAIN|LOG_PANIC, "unable to expand message_size_limit: "
2616 "%s", expand_string_message);
2618 log_write(0, LOG_MAIN|LOG_PANIC, "invalid message_size_limit: "
2619 "%s", expand_string_message);
2620 smtp_closedown(US"Temporary local problem - please try later");
2624 /* When a message is input locally via the -bs or -bS options, sender_host_
2625 unknown is set unless -oMa was used to force an IP address, in which case it
2626 is checked like a real remote connection. When -bs is used from inetd, this
2627 flag is not set, causing the sending host to be checked. The code that deals
2628 with IP source routing (if configured) is never required for -bs or -bS and
2629 the flag sender_host_notsocket is used to suppress it.
2631 If smtp_accept_max and smtp_accept_reserve are set, keep some connections in
2632 reserve for certain hosts and/or networks. */
2634 if (!f.sender_host_unknown)
2637 BOOL reserved_host = FALSE;
2639 /* Look up IP options (source routing info) on the socket if this is not an
2640 -oMa "host", and if any are found, log them and drop the connection.
2642 Linux (and others now, see below) is different to everyone else, so there
2643 has to be some conditional compilation here. Versions of Linux before 2.1.15
2644 used a structure whose name was "options". Somebody finally realized that
2645 this name was silly, and it got changed to "ip_options". I use the
2646 newer name here, but there is a fudge in the script that sets up os.h
2647 to define a macro in older Linux systems.
2649 Sigh. Linux is a fast-moving target. Another generation of Linux uses
2650 glibc 2, which has chosen ip_opts for the structure name. This is now
2651 really a glibc thing rather than a Linux thing, so the condition name
2652 has been changed to reflect this. It is relevant also to GNU/Hurd.
2654 Mac OS 10.x (Darwin) is like the later glibc versions, but without the
2655 setting of the __GLIBC__ macro, so we can't detect it automatically. There's
2656 a special macro defined in the os.h file.
2658 Some DGUX versions on older hardware appear not to support IP options at
2659 all, so there is now a general macro which can be set to cut out this
2662 How to do this properly in IPv6 is not yet known. */
2664 #if !HAVE_IPV6 && !defined(NO_IP_OPTIONS)
2666 #ifdef GLIBC_IP_OPTIONS
2667 #if (!defined __GLIBC__) || (__GLIBC__ < 2)
2672 #elif defined DARWIN_IP_OPTIONS
2678 if (!host_checking && !f.sender_host_notsocket)
2681 EXIM_SOCKLEN_T optlen = sizeof(struct ip_options) + MAX_IPOPTLEN;
2682 struct ip_options *ipopt = store_get(optlen, GET_UNTAINTED);
2684 struct ip_opts ipoptblock;
2685 struct ip_opts *ipopt = &ipoptblock;
2686 EXIM_SOCKLEN_T optlen = sizeof(ipoptblock);
2688 struct ipoption ipoptblock;
2689 struct ipoption *ipopt = &ipoptblock;
2690 EXIM_SOCKLEN_T optlen = sizeof(ipoptblock);
2693 /* Occasional genuine failures of getsockopt() have been seen - for
2694 example, "reset by peer". Therefore, just log and give up on this
2695 call, unless the error is ENOPROTOOPT. This error is given by systems
2696 that have the interfaces but not the mechanism - e.g. GNU/Hurd at the time
2697 of writing. So for that error, carry on - we just can't do an IP options
2700 DEBUG(D_receive) debug_printf("checking for IP options\n");
2702 if (getsockopt(fileno(smtp_out), IPPROTO_IP, IP_OPTIONS, US (ipopt),
2705 if (errno != ENOPROTOOPT)
2707 log_write(0, LOG_MAIN, "getsockopt() failed from %s: %s",
2708 host_and_ident(FALSE), strerror(errno));
2709 smtp_printf("451 SMTP service not available\r\n", FALSE);
2714 /* Deal with any IP options that are set. On the systems I have looked at,
2715 the value of MAX_IPOPTLEN has been 40, meaning that there should never be
2716 more logging data than will fit in big_buffer. Nevertheless, after somebody
2717 questioned this code, I've added in some paranoid checking. */
2719 else if (optlen > 0)
2721 uschar *p = big_buffer;
2722 uschar *pend = big_buffer + big_buffer_size;
2725 struct in_addr addr;
2728 uschar *optstart = US (ipopt->__data);
2730 uschar *optstart = US (ipopt->ip_opts);
2732 uschar *optstart = US (ipopt->ipopt_list);
2735 DEBUG(D_receive) debug_printf("IP options exist\n");
2737 Ustrcpy(p, "IP options on incoming call:");
2740 for (uschar * opt = optstart; opt && opt < US (ipopt) + optlen; )
2753 if (!string_format(p, pend-p, " %s [@%s",
2754 (*opt == IPOPT_SSRR)? "SSRR" : "LSRR",
2756 inet_ntoa(*((struct in_addr *)(&(ipopt->faddr))))))
2758 inet_ntoa(ipopt->ip_dst)))
2760 inet_ntoa(ipopt->ipopt_dst)))
2768 optcount = (opt[1] - 3) / sizeof(struct in_addr);
2770 while (optcount-- > 0)
2772 memcpy(&addr, adptr, sizeof(addr));
2773 if (!string_format(p, pend - p - 1, "%s%s",
2774 (optcount == 0)? ":" : "@", inet_ntoa(addr)))
2780 adptr += sizeof(struct in_addr);
2788 if (pend - p < 4 + 3*opt[1]) { opt = NULL; break; }
2791 for (int i = 0; i < opt[1]; i++)
2792 p += sprintf(CS p, "%2.2x ", opt[i]);
2800 log_write(0, LOG_MAIN, "%s", big_buffer);
2802 /* Refuse any call with IP options. This is what tcpwrappers 7.5 does. */
2804 log_write(0, LOG_MAIN|LOG_REJECT,
2805 "connection from %s refused (IP options)", host_and_ident(FALSE));
2807 smtp_printf("554 SMTP service not available\r\n", FALSE);
2811 /* Length of options = 0 => there are no options */
2813 else DEBUG(D_receive) debug_printf("no IP options found\n");
2815 #endif /* HAVE_IPV6 && !defined(NO_IP_OPTIONS) */
2817 /* Set keep-alive in socket options. The option is on by default. This
2818 setting is an attempt to get rid of some hanging connections that stick in
2819 read() when the remote end (usually a dialup) goes away. */
2821 if (smtp_accept_keepalive && !f.sender_host_notsocket)
2822 ip_keepalive(fileno(smtp_out), sender_host_address, FALSE);
2824 /* If the current host matches host_lookup, set the name by doing a
2825 reverse lookup. On failure, sender_host_name will be NULL and
2826 host_lookup_failed will be TRUE. This may or may not be serious - optional
2829 if (verify_check_host(&host_lookup) == OK)
2831 (void)host_name_lookup();
2832 host_build_sender_fullhost();
2835 /* Delay this until we have the full name, if it is looked up. */
2837 set_process_info("handling incoming connection from %s",
2838 host_and_ident(FALSE));
2840 /* Expand smtp_receive_timeout, if needed */
2842 if (smtp_receive_timeout_s)
2845 if ( !(exp = expand_string(smtp_receive_timeout_s))
2847 || (smtp_receive_timeout = readconf_readtime(exp, 0, FALSE)) < 0
2849 log_write(0, LOG_MAIN|LOG_PANIC,
2850 "bad value for smtp_receive_timeout: '%s'", exp ? exp : US"");
2853 /* Test for explicit connection rejection */
2855 if (verify_check_host(&host_reject_connection) == OK)
2857 log_write(L_connection_reject, LOG_MAIN|LOG_REJECT, "refused connection "
2858 "from %s (host_reject_connection)", host_and_ident(FALSE));
2859 smtp_printf("554 SMTP service not available\r\n", FALSE);
2863 /* Test with TCP Wrappers if so configured. There is a problem in that
2864 hosts_ctl() returns 0 (deny) under a number of system failure circumstances,
2865 such as disks dying. In these cases, it is desirable to reject with a 4xx
2866 error instead of a 5xx error. There isn't a "right" way to detect such
2867 problems. The following kludge is used: errno is zeroed before calling
2868 hosts_ctl(). If the result is "reject", a 5xx error is given only if the
2869 value of errno is 0 or ENOENT (which happens if /etc/hosts.{allow,deny} does
2872 #ifdef USE_TCP_WRAPPERS
2874 if (!(tcp_wrappers_name = expand_string(tcp_wrappers_daemon_name)))
2875 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "Expansion of \"%s\" "
2876 "(tcp_wrappers_name) failed: %s", string_printing(tcp_wrappers_name),
2877 expand_string_message);
2879 if (!hosts_ctl(tcp_wrappers_name,
2880 sender_host_name ? CS sender_host_name : STRING_UNKNOWN,
2881 sender_host_address ? CS sender_host_address : STRING_UNKNOWN,
2882 sender_ident ? CS sender_ident : STRING_UNKNOWN))
2884 if (errno == 0 || errno == ENOENT)
2886 HDEBUG(D_receive) debug_printf("tcp wrappers rejection\n");
2887 log_write(L_connection_reject,
2888 LOG_MAIN|LOG_REJECT, "refused connection from %s "
2889 "(tcp wrappers)", host_and_ident(FALSE));
2890 smtp_printf("554 SMTP service not available\r\n", FALSE);
2894 int save_errno = errno;
2895 HDEBUG(D_receive) debug_printf("tcp wrappers rejected with unexpected "
2896 "errno value %d\n", save_errno);
2897 log_write(L_connection_reject,
2898 LOG_MAIN|LOG_REJECT, "temporarily refused connection from %s "
2899 "(tcp wrappers errno=%d)", host_and_ident(FALSE), save_errno);
2900 smtp_printf("451 Temporary local problem - please try later\r\n", FALSE);
2906 /* Check for reserved slots. The value of smtp_accept_count has already been
2907 incremented to include this process. */
2909 if (smtp_accept_max > 0 &&
2910 smtp_accept_count > smtp_accept_max - smtp_accept_reserve)
2912 if ((rc = verify_check_host(&smtp_reserve_hosts)) != OK)
2914 log_write(L_connection_reject,
2915 LOG_MAIN, "temporarily refused connection from %s: not in "
2916 "reserve list: connected=%d max=%d reserve=%d%s",
2917 host_and_ident(FALSE), smtp_accept_count - 1, smtp_accept_max,
2918 smtp_accept_reserve, (rc == DEFER)? " (lookup deferred)" : "");
2919 smtp_printf("421 %s: Too many concurrent SMTP connections; "
2920 "please try again later\r\n", FALSE, smtp_active_hostname);
2923 reserved_host = TRUE;
2926 /* If a load level above which only messages from reserved hosts are
2927 accepted is set, check the load. For incoming calls via the daemon, the
2928 check is done in the superior process if there are no reserved hosts, to
2929 save a fork. In all cases, the load average will already be available
2930 in a global variable at this point. */
2932 if (smtp_load_reserve >= 0 &&
2933 load_average > smtp_load_reserve &&
2935 verify_check_host(&smtp_reserve_hosts) != OK)
2937 log_write(L_connection_reject,
2938 LOG_MAIN, "temporarily refused connection from %s: not in "
2939 "reserve list and load average = %.2f", host_and_ident(FALSE),
2940 (double)load_average/1000.0);
2941 smtp_printf("421 %s: Too much load; please try again later\r\n", FALSE,
2942 smtp_active_hostname);
2946 /* Determine whether unqualified senders or recipients are permitted
2947 for this host. Unfortunately, we have to do this every time, in order to
2948 set the flags so that they can be inspected when considering qualifying
2949 addresses in the headers. For a site that permits no qualification, this
2950 won't take long, however. */
2952 f.allow_unqualified_sender =
2953 verify_check_host(&sender_unqualified_hosts) == OK;
2955 f.allow_unqualified_recipient =
2956 verify_check_host(&recipient_unqualified_hosts) == OK;
2958 /* Determine whether HELO/EHLO is required for this host. The requirement
2959 can be hard or soft. */
2961 fl.helo_verify_required = verify_check_host(&helo_verify_hosts) == OK;
2962 if (!fl.helo_verify_required)
2963 fl.helo_verify = verify_check_host(&helo_try_verify_hosts) == OK;
2965 /* Determine whether this hosts is permitted to send syntactic junk
2966 after a HELO or EHLO command. */
2968 fl.helo_accept_junk = verify_check_host(&helo_accept_junk_hosts) == OK;
2971 /* For batch SMTP input we are now done. */
2973 if (smtp_batched_input) return TRUE;
2975 /* If valid Proxy Protocol source is connecting, set up session.
2976 Failure will not allow any SMTP function other than QUIT. */
2978 #ifdef SUPPORT_PROXY
2979 proxy_session = FALSE;
2980 f.proxy_session_failed = FALSE;
2981 if (check_proxy_protocol_host())
2982 setup_proxy_protocol_host();
2985 /* Start up TLS if tls_on_connect is set. This is for supporting the legacy
2986 smtps port for use with older style SSL MTAs. */
2989 if (tls_in.on_connect)
2991 if (tls_server_start(&user_msg) != OK)
2992 return smtp_log_tls_fail(user_msg);
2993 cmd_list[CMD_LIST_TLS_AUTH].is_mail_cmd = TRUE;
2997 /* Run the connect ACL if it exists */
3000 if (acl_smtp_connect)
3003 if ((rc = acl_check(ACL_WHERE_CONNECT, NULL, acl_smtp_connect, &user_msg,
3006 (void) smtp_handle_acl_fail(ACL_WHERE_CONNECT, rc, user_msg, log_msg);
3011 /* Output the initial message for a two-way SMTP connection. It may contain
3012 newlines, which then cause a multi-line response to be given. */
3014 code = US"220"; /* Default status code */
3015 esc = US""; /* Default extended status code */
3016 esclen = 0; /* Length of esc */
3020 if (!(s = expand_string(smtp_banner)))
3021 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "Expansion of \"%s\" (smtp_banner) "
3022 "failed: %s", smtp_banner, expand_string_message);
3028 smtp_message_code(&code, &codelen, &s, NULL, TRUE);
3032 esclen = codelen - 4;
3036 /* Remove any terminating newlines; might as well remove trailing space too */
3039 while (p > s && isspace(p[-1])) p--;
3040 s = string_copyn(s, p-s);
3042 /* It seems that CC:Mail is braindead, and assumes that the greeting message
3043 is all contained in a single IP packet. The original code wrote out the
3044 greeting using several calls to fprint/fputc, and on busy servers this could
3045 cause it to be split over more than one packet - which caused CC:Mail to fall
3046 over when it got the second part of the greeting after sending its first
3047 command. Sigh. To try to avoid this, build the complete greeting message
3048 first, and output it in one fell swoop. This gives a better chance of it
3049 ending up as a single packet. */
3051 ss = string_get(256);
3054 do /* At least once, in case we have an empty string */
3057 uschar *linebreak = Ustrchr(p, '\n');
3058 ss = string_catn(ss, code, 3);
3062 ss = string_catn(ss, US" ", 1);
3066 len = linebreak - p;
3067 ss = string_catn(ss, US"-", 1);
3069 ss = string_catn(ss, esc, esclen);
3070 ss = string_catn(ss, p, len);
3071 ss = string_catn(ss, US"\r\n", 2);
3077 /* Before we write the banner, check that there is no input pending, unless
3078 this synchronisation check is disabled. */
3080 #ifndef DISABLE_PIPE_CONNECT
3081 fl.pipe_connect_acceptable =
3082 sender_host_address && verify_check_host(&pipe_connect_advertise_hosts) == OK;
3085 if (fl.pipe_connect_acceptable)
3086 f.smtp_in_early_pipe_used = TRUE;
3092 unsigned n = smtp_inend - smtp_inptr;
3093 if (n > 128) n = 128;
3095 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP protocol "
3096 "synchronization error (input sent without waiting for greeting): "
3097 "rejected connection from %s input=\"%s\"", host_and_ident(TRUE),
3098 string_printing(string_copyn(smtp_inptr, n)));
3099 smtp_printf("554 SMTP synchronization error\r\n", FALSE);
3103 /* Now output the banner */
3104 /*XXX the ehlo-resp code does its own tls/nontls bit. Maybe subroutine that? */
3107 #ifndef DISABLE_PIPE_CONNECT
3108 fl.pipe_connect_acceptable && pipeline_connect_sends(),
3112 string_from_gstring(ss));
3114 /* Attempt to see if we sent the banner before the last ACK of the 3-way
3115 handshake arrived. If so we must have managed a TFO. */
3118 if (sender_host_address && !f.sender_host_notsocket) tfo_in_check();
3128 /*************************************************
3129 * Handle SMTP syntax and protocol errors *
3130 *************************************************/
3132 /* Write to the log for SMTP syntax errors in incoming commands, if configured
3133 to do so. Then transmit the error response. The return value depends on the
3134 number of syntax and protocol errors in this SMTP session.
3137 type error type, given as a log flag bit
3138 code response code; <= 0 means don't send a response
3139 data data to reflect in the response (can be NULL)
3140 errmess the error message
3142 Returns: -1 limit of syntax/protocol errors NOT exceeded
3143 +1 limit of syntax/protocol errors IS exceeded
3145 These values fit in with the values of the "done" variable in the main
3146 processing loop in smtp_setup_msg(). */
3149 synprot_error(int type, int code, uschar *data, uschar *errmess)
3153 log_write(type, LOG_MAIN, "SMTP %s error in \"%s\" %s %s",
3154 type == L_smtp_syntax_error ? "syntax" : "protocol",
3155 string_printing(smtp_cmd_buffer), host_and_ident(TRUE), errmess);
3157 if (++synprot_error_count > smtp_max_synprot_errors)
3160 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
3161 "syntax or protocol errors (last command was \"%s\", %s)",
3162 host_and_ident(FALSE), string_printing(smtp_cmd_buffer),
3163 string_from_gstring(s_connhad_log(NULL))
3169 smtp_printf("%d%c%s%s%s\r\n", FALSE, code, yield == 1 ? '-' : ' ',
3170 data ? data : US"", data ? US": " : US"", errmess);
3172 smtp_printf("%d Too many syntax or protocol errors\r\n", FALSE, code);
3181 /*************************************************
3182 * Send SMTP response, possibly multiline *
3183 *************************************************/
3185 /* There are, it seems, broken clients out there that cannot handle multiline
3186 responses. If no_multiline_responses is TRUE (it can be set from an ACL), we
3187 output nothing for non-final calls, and only the first line for anything else.
3190 code SMTP code, may involve extended status codes
3191 codelen length of smtp code; if > 4 there's an ESC
3192 final FALSE if the last line isn't the final line
3193 msg message text, possibly containing newlines
3199 smtp_respond(uschar* code, int codelen, BOOL final, uschar *msg)
3204 if (!final && f.no_multiline_responses) return;
3209 esclen = codelen - 4;
3212 /* If this is the first output for a (non-batch) RCPT command, see if all RCPTs
3213 have had the same. Note: this code is also present in smtp_printf(). It would
3214 be tidier to have it only in one place, but when it was added, it was easier to
3215 do it that way, so as not to have to mess with the code for the RCPT command,
3216 which sometimes uses smtp_printf() and sometimes smtp_respond(). */
3218 if (fl.rcpt_in_progress)
3220 if (!rcpt_smtp_response)
3221 rcpt_smtp_response = string_copy(msg);
3222 else if (fl.rcpt_smtp_response_same &&
3223 Ustrcmp(rcpt_smtp_response, msg) != 0)
3224 fl.rcpt_smtp_response_same = FALSE;
3225 fl.rcpt_in_progress = FALSE;
3228 /* Now output the message, splitting it up into multiple lines if necessary.
3229 We only handle pipelining these responses as far as nonfinal/final groups,
3230 not the whole MAIL/RCPT/DATA response set. */
3234 uschar *nl = Ustrchr(msg, '\n');
3237 smtp_printf("%.3s%c%.*s%s\r\n", !final, code, final ? ' ':'-', esclen, esc, msg);
3240 else if (nl[1] == 0 || f.no_multiline_responses)
3242 smtp_printf("%.3s%c%.*s%.*s\r\n", !final, code, final ? ' ':'-', esclen, esc,
3243 (int)(nl - msg), msg);
3248 smtp_printf("%.3s-%.*s%.*s\r\n", TRUE, code, esclen, esc, (int)(nl - msg), msg);
3250 Uskip_whitespace(&msg);
3258 /*************************************************
3259 * Parse user SMTP message *
3260 *************************************************/
3262 /* This function allows for user messages overriding the response code details
3263 by providing a suitable response code string at the start of the message
3264 user_msg. Check the message for starting with a response code and optionally an
3265 extended status code. If found, check that the first digit is valid, and if so,
3266 change the code pointer and length to use the replacement. An invalid code
3267 causes a panic log; in this case, if the log messages is the same as the user
3268 message, we must also adjust the value of the log message to show the code that
3269 is actually going to be used (the original one).
3271 This function is global because it is called from receive.c as well as within
3274 Note that the code length returned includes the terminating whitespace
3275 character, which is always included in the regex match.
3278 code SMTP code, may involve extended status codes
3279 codelen length of smtp code; if > 4 there's an ESC
3281 log_msg optional log message, to be adjusted with the new SMTP code
3282 check_valid if true, verify the response code
3288 smtp_message_code(uschar **code, int *codelen, uschar **msg, uschar **log_msg,
3294 if (!msg || !*msg || !regex_match(regex_smtp_code, *msg, -1, &match))
3297 len = Ustrlen(match);
3298 if (check_valid && (*msg)[0] != (*code)[0])
3300 log_write(0, LOG_MAIN|LOG_PANIC, "configured error code starts with "
3301 "incorrect digit (expected %c) in \"%s\"", (*code)[0], *msg);
3302 if (log_msg && *log_msg == *msg)
3303 *log_msg = string_sprintf("%s %s", *code, *log_msg + len);
3308 *codelen = len; /* Includes final space */
3310 *msg += len; /* Chop the code off the message */
3317 /*************************************************
3318 * Handle an ACL failure *
3319 *************************************************/
3321 /* This function is called when acl_check() fails. As well as calls from within
3322 this module, it is called from receive.c for an ACL after DATA. It sorts out
3323 logging the incident, and sends the error response. A message containing
3324 newlines is turned into a multiline SMTP response, but for logging, only the
3327 There's a table of default permanent failure response codes to use in
3328 globals.c, along with the table of names. VFRY is special. Despite RFC1123 it
3329 defaults disabled in Exim. However, discussion in connection with RFC 821bis
3330 (aka RFC 2821) has concluded that the response should be 252 in the disabled
3331 state, because there are broken clients that try VRFY before RCPT. A 5xx
3332 response should be given only when the address is positively known to be
3333 undeliverable. Sigh. We return 252 if there is no VRFY ACL or it provides
3334 no explicit code, but if there is one we let it know best.
3335 Also, for ETRN, 458 is given on refusal, and for AUTH, 503.
3337 From Exim 4.63, it is possible to override the response code details by
3338 providing a suitable response code string at the start of the message provided
3339 in user_msg. The code's first digit is checked for validity.
3342 where where the ACL was called from
3344 user_msg a message that can be included in an SMTP response
3345 log_msg a message for logging
3347 Returns: 0 in most cases
3348 2 if the failure code was FAIL_DROP, in which case the
3349 SMTP connection should be dropped (this value fits with the
3350 "done" variable in smtp_setup_msg() below)
3354 smtp_handle_acl_fail(int where, int rc, uschar *user_msg, uschar *log_msg)
3356 BOOL drop = rc == FAIL_DROP;
3360 uschar *sender_info = US"";
3363 if (drop) rc = FAIL;
3365 /* Set the default SMTP code, and allow a user message to change it. */
3367 smtp_code = rc == FAIL ? acl_wherecodes[where] : US"451";
3368 smtp_message_code(&smtp_code, &codelen, &user_msg, &log_msg,
3369 where != ACL_WHERE_VRFY);
3371 /* We used to have sender_address here; however, there was a bug that was not
3372 updating sender_address after a rewrite during a verify. When this bug was
3373 fixed, sender_address at this point became the rewritten address. I'm not sure
3374 this is what should be logged, so I've changed to logging the unrewritten
3375 address to retain backward compatibility. */
3379 #ifdef WITH_CONTENT_SCAN
3380 case ACL_WHERE_MIME: what = US"during MIME ACL checks"; break;
3382 case ACL_WHERE_PREDATA: what = US"DATA"; break;
3383 case ACL_WHERE_DATA: what = US"after DATA"; break;
3384 #ifndef DISABLE_PRDR
3385 case ACL_WHERE_PRDR: what = US"after DATA PRDR"; break;
3389 uschar * place = smtp_cmd_data ? smtp_cmd_data : US"in \"connect\" ACL";
3392 if (where == ACL_WHERE_AUTH) /* avoid logging auth creds */
3395 for (s = smtp_cmd_data; *s && !isspace(*s); ) s++;
3396 lim = s - smtp_cmd_data; /* atop after method */
3398 what = string_sprintf("%s %.*s", acl_wherenames[where], lim, place);
3403 case ACL_WHERE_RCPT:
3404 case ACL_WHERE_DATA:
3405 #ifdef WITH_CONTENT_SCAN
3406 case ACL_WHERE_MIME:
3408 sender_info = string_sprintf("F=<%s>%s%s%s%s ",
3409 sender_address_unrewritten ? sender_address_unrewritten : sender_address,
3410 sender_host_authenticated ? US" A=" : US"",
3411 sender_host_authenticated ? sender_host_authenticated : US"",
3412 sender_host_authenticated && authenticated_id ? US":" : US"",
3413 sender_host_authenticated && authenticated_id ? authenticated_id : US""
3418 /* If there's been a sender verification failure with a specific message, and
3419 we have not sent a response about it yet, do so now, as a preliminary line for
3420 failures, but not defers. However, always log it for defer, and log it for fail
3421 unless the sender_verify_fail log selector has been turned off. */
3423 if (sender_verified_failed &&
3424 !testflag(sender_verified_failed, af_sverify_told))
3426 BOOL save_rcpt_in_progress = fl.rcpt_in_progress;
3427 fl.rcpt_in_progress = FALSE; /* So as not to treat these as the error */
3429 setflag(sender_verified_failed, af_sverify_told);
3431 if (rc != FAIL || LOGGING(sender_verify_fail))
3432 log_write(0, LOG_MAIN|LOG_REJECT, "%s sender verify %s for <%s>%s",
3433 host_and_ident(TRUE),
3434 ((sender_verified_failed->special_action & 255) == DEFER)? "defer":"fail",
3435 sender_verified_failed->address,
3436 (sender_verified_failed->message == NULL)? US"" :
3437 string_sprintf(": %s", sender_verified_failed->message));
3439 if (rc == FAIL && sender_verified_failed->user_message)
3440 smtp_respond(smtp_code, codelen, FALSE, string_sprintf(
3441 testflag(sender_verified_failed, af_verify_pmfail)?
3442 "Postmaster verification failed while checking <%s>\n%s\n"
3443 "Several RFCs state that you are required to have a postmaster\n"
3444 "mailbox for each mail domain. This host does not accept mail\n"
3445 "from domains whose servers reject the postmaster address."
3447 testflag(sender_verified_failed, af_verify_nsfail)?
3448 "Callback setup failed while verifying <%s>\n%s\n"
3449 "The initial connection, or a HELO or MAIL FROM:<> command was\n"
3450 "rejected. Refusing MAIL FROM:<> does not help fight spam, disregards\n"
3451 "RFC requirements, and stops you from receiving standard bounce\n"
3452 "messages. This host does not accept mail from domains whose servers\n"
3455 "Verification failed for <%s>\n%s",
3456 sender_verified_failed->address,
3457 sender_verified_failed->user_message));
3459 fl.rcpt_in_progress = save_rcpt_in_progress;
3462 /* Sort out text for logging */
3464 log_msg = log_msg ? string_sprintf(": %s", log_msg) : US"";
3465 if ((lognl = Ustrchr(log_msg, '\n'))) *lognl = 0;
3467 /* Send permanent failure response to the command, but the code used isn't
3468 always a 5xx one - see comments at the start of this function. If the original
3469 rc was FAIL_DROP we drop the connection and yield 2. */
3472 smtp_respond(smtp_code, codelen, TRUE,
3473 user_msg ? user_msg : US"Administrative prohibition");
3475 /* Send temporary failure response to the command. Don't give any details,
3476 unless acl_temp_details is set. This is TRUE for a callout defer, a "defer"
3477 verb, and for a header verify when smtp_return_error_details is set.
3479 This conditional logic is all somewhat of a mess because of the odd
3480 interactions between temp_details and return_error_details. One day it should
3481 be re-implemented in a tidier fashion. */
3484 if (f.acl_temp_details && user_msg)
3486 if ( smtp_return_error_details
3487 && sender_verified_failed
3488 && sender_verified_failed->message
3490 smtp_respond(smtp_code, codelen, FALSE, sender_verified_failed->message);
3492 smtp_respond(smtp_code, codelen, TRUE, user_msg);
3495 smtp_respond(smtp_code, codelen, TRUE,
3496 US"Temporary local problem - please try later");
3498 /* Log the incident to the logs that are specified by log_reject_target
3499 (default main, reject). This can be empty to suppress logging of rejections. If
3500 the connection is not forcibly to be dropped, return 0. Otherwise, log why it
3501 is closing if required and return 2. */
3503 if (log_reject_target != 0)
3506 gstring * g = s_tlslog(NULL);
3507 uschar * tls = string_from_gstring(g);
3508 if (!tls) tls = US"";
3510 uschar * tls = US"";
3512 log_write(where == ACL_WHERE_CONNECT ? L_connection_reject : 0,
3513 log_reject_target, "%s%s%s %s%srejected %s%s",
3514 LOGGING(dnssec) && sender_host_dnssec ? US" DS" : US"",
3515 host_and_ident(TRUE),
3518 rc == FAIL ? US"" : US"temporarily ",
3522 if (!drop) return 0;
3524 log_write(L_smtp_connection, LOG_MAIN, "%s closed by DROP in ACL",
3525 smtp_get_connection_info());
3527 /* Run the not-quit ACL, but without any custom messages. This should not be a
3528 problem, because we get here only if some other ACL has issued "drop", and
3529 in that case, *its* custom messages will have been used above. */
3531 smtp_notquit_exit(US"acl-drop", NULL, NULL);
3538 /*************************************************
3539 * Handle SMTP exit when QUIT is not given *
3540 *************************************************/
3542 /* This function provides a logging/statistics hook for when an SMTP connection
3543 is dropped on the floor or the other end goes away. It's a global function
3544 because it's called from receive.c as well as this module. As well as running
3545 the NOTQUIT ACL, if there is one, this function also outputs a final SMTP
3546 response, either with a custom message from the ACL, or using a default. There
3547 is one case, however, when no message is output - after "drop". In that case,
3548 the ACL that obeyed "drop" has already supplied the custom message, and NULL is
3549 passed to this function.
3551 In case things go wrong while processing this function, causing an error that
3552 may re-enter this function, there is a recursion check.
3555 reason What $smtp_notquit_reason will be set to in the ACL;
3556 if NULL, the ACL is not run
3557 code The error code to return as part of the response
3558 defaultrespond The default message if there's no user_msg
3564 smtp_notquit_exit(uschar *reason, uschar *code, uschar *defaultrespond, ...)
3567 uschar *user_msg = NULL;
3568 uschar *log_msg = NULL;
3570 /* Check for recursive call */
3572 if (fl.smtp_exit_function_called)
3574 log_write(0, LOG_PANIC, "smtp_notquit_exit() called more than once (%s)",
3578 fl.smtp_exit_function_called = TRUE;
3580 /* Call the not-QUIT ACL, if there is one, unless no reason is given. */
3582 if (acl_smtp_notquit && reason)
3584 smtp_notquit_reason = reason;
3585 if ((rc = acl_check(ACL_WHERE_NOTQUIT, NULL, acl_smtp_notquit, &user_msg,
3586 &log_msg)) == ERROR)
3587 log_write(0, LOG_MAIN|LOG_PANIC, "ACL for not-QUIT returned ERROR: %s",
3591 /* If the connection was dropped, we certainly are no longer talking TLS */
3592 tls_in.active.sock = -1;
3594 /* Write an SMTP response if we are expected to give one. As the default
3595 responses are all internal, they should be reasonable size. */
3597 if (code && defaultrespond)
3600 smtp_respond(code, 3, TRUE, user_msg);
3606 va_start(ap, defaultrespond);
3607 g = string_vformat(NULL, SVFMT_EXTEND|SVFMT_REBUFFER, CS defaultrespond, ap);
3609 smtp_printf("%s %s\r\n", FALSE, code, string_from_gstring(g));
3618 /*************************************************
3619 * Verify HELO argument *
3620 *************************************************/
3622 /* This function is called if helo_verify_hosts or helo_try_verify_hosts is
3623 matched. It is also called from ACL processing if verify = helo is used and
3624 verification was not previously tried (i.e. helo_try_verify_hosts was not
3625 matched). The result of its processing is to set helo_verified and
3626 helo_verify_failed. These variables should both be FALSE for this function to
3629 Note that EHLO/HELO is legitimately allowed to quote an address literal. Allow
3630 for IPv6 ::ffff: literals.
3633 Returns: TRUE if testing was completed;
3634 FALSE on a temporary failure
3638 smtp_verify_helo(void)
3642 HDEBUG(D_receive) debug_printf("verifying EHLO/HELO argument \"%s\"\n",
3645 if (sender_helo_name == NULL)
3647 HDEBUG(D_receive) debug_printf("no EHLO/HELO command was issued\n");
3650 /* Deal with the case of -bs without an IP address */
3652 else if (sender_host_address == NULL)
3654 HDEBUG(D_receive) debug_printf("no client IP address: assume success\n");
3655 f.helo_verified = TRUE;
3658 /* Deal with the more common case when there is a sending IP address */
3660 else if (sender_helo_name[0] == '[')
3662 f.helo_verified = Ustrncmp(sender_helo_name+1, sender_host_address,
3663 Ustrlen(sender_host_address)) == 0;
3666 if (!f.helo_verified)
3668 if (strncmpic(sender_host_address, US"::ffff:", 7) == 0)
3669 f.helo_verified = Ustrncmp(sender_helo_name + 1,
3670 sender_host_address + 7, Ustrlen(sender_host_address) - 7) == 0;
3675 { if (f.helo_verified) debug_printf("matched host address\n"); }
3678 /* Do a reverse lookup if one hasn't already given a positive or negative
3679 response. If that fails, or the name doesn't match, try checking with a forward
3684 if (sender_host_name == NULL && !host_lookup_failed)
3685 yield = host_name_lookup() != DEFER;
3687 /* If a host name is known, check it and all its aliases. */
3689 if (sender_host_name)
3690 if ((f.helo_verified = strcmpic(sender_host_name, sender_helo_name) == 0))
3692 sender_helo_dnssec = sender_host_dnssec;
3693 HDEBUG(D_receive) debug_printf("matched host name\n");
3697 uschar **aliases = sender_host_aliases;
3699 if ((f.helo_verified = strcmpic(*aliases++, sender_helo_name) == 0))
3701 sender_helo_dnssec = sender_host_dnssec;
3705 HDEBUG(D_receive) if (f.helo_verified)
3706 debug_printf("matched alias %s\n", *(--aliases));
3709 /* Final attempt: try a forward lookup of the helo name */
3711 if (!f.helo_verified)
3715 {.name = sender_helo_name, .address = NULL, .mx = MX_NONE, .next = NULL};
3717 {.request = US"*", .require = US""};
3719 HDEBUG(D_receive) debug_printf("getting IP address for %s\n",
3721 rc = host_find_bydns(&h, NULL, HOST_FIND_BY_A | HOST_FIND_BY_AAAA,
3722 NULL, NULL, NULL, &d, NULL, NULL);
3723 if (rc == HOST_FOUND || rc == HOST_FOUND_LOCAL)
3724 for (host_item * hh = &h; hh; hh = hh->next)
3725 if (Ustrcmp(hh->address, sender_host_address) == 0)
3727 f.helo_verified = TRUE;
3728 if (h.dnssec == DS_YES) sender_helo_dnssec = TRUE;
3730 debug_printf("IP address for %s matches calling address\n"
3731 "Forward DNS security status: %sverified\n",
3732 sender_helo_name, sender_helo_dnssec ? "" : "un");
3738 if (!f.helo_verified) f.helo_verify_failed = TRUE; /* We've tried ... */
3745 /*************************************************
3746 * Send user response message *
3747 *************************************************/
3749 /* This function is passed a default response code and a user message. It calls
3750 smtp_message_code() to check and possibly modify the response code, and then
3751 calls smtp_respond() to transmit the response. I put this into a function
3752 just to avoid a lot of repetition.
3755 code the response code
3756 user_msg the user message
3762 smtp_user_msg(uschar *code, uschar *user_msg)
3765 smtp_message_code(&code, &len, &user_msg, NULL, TRUE);
3766 smtp_respond(code, len, TRUE, user_msg);
3772 smtp_in_auth(auth_instance *au, uschar ** smtp_resp, uschar ** errmsg)
3774 const uschar *set_id = NULL;
3777 /* Set up globals for error messages */
3779 authenticator_name = au->name;
3780 driver_srcfile = au->srcfile;
3781 driver_srcline = au->srcline;
3783 /* Run the checking code, passing the remainder of the command line as
3784 data. Initials the $auth<n> variables as empty. Initialize $0 empty and set
3785 it as the only set numerical variable. The authenticator may set $auth<n>
3786 and also set other numeric variables. The $auth<n> variables are preferred
3787 nowadays; the numerical variables remain for backwards compatibility.
3789 Afterwards, have a go at expanding the set_id string, even if
3790 authentication failed - for bad passwords it can be useful to log the
3791 userid. On success, require set_id to expand and exist, and put it in
3792 authenticated_id. Save this in permanent store, as the working store gets
3793 reset at HELO, RSET, etc. */
3795 for (int i = 0; i < AUTH_VARS; i++) auth_vars[i] = NULL;
3797 expand_nlength[0] = 0; /* $0 contains nothing */
3799 rc = (au->info->servercode)(au, smtp_cmd_data);
3800 if (au->set_id) set_id = expand_string(au->set_id);
3801 expand_nmax = -1; /* Reset numeric variables */
3802 for (int i = 0; i < AUTH_VARS; i++) auth_vars[i] = NULL; /* Reset $auth<n> */
3803 driver_srcfile = authenticator_name = NULL; driver_srcline = 0;
3805 /* The value of authenticated_id is stored in the spool file and printed in
3806 log lines. It must not contain binary zeros or newline characters. In
3807 normal use, it never will, but when playing around or testing, this error
3808 can (did) happen. To guard against this, ensure that the id contains only
3809 printing characters. */
3811 if (set_id) set_id = string_printing(set_id);
3813 /* For the non-OK cases, set up additional logging data if set_id
3817 set_id = set_id && *set_id
3818 ? string_sprintf(" (set_id=%s)", set_id) : US"";
3820 /* Switch on the result */
3825 if (!au->set_id || set_id) /* Complete success */
3827 if (set_id) authenticated_id = string_copy_perm(set_id, TRUE);
3828 sender_host_authenticated = au->name;
3829 sender_host_auth_pubname = au->public_name;
3830 authentication_failed = FALSE;
3831 authenticated_fail_id = NULL; /* Impossible to already be set? */
3834 (sender_host_address ? protocols : protocols_local)
3835 [pextend + pauthed + (tls_in.active.sock >= 0 ? pcrpted:0)];
3836 *smtp_resp = *errmsg = US"235 Authentication succeeded";
3837 authenticated_by = au;
3841 /* Authentication succeeded, but we failed to expand the set_id string.
3842 Treat this as a temporary error. */
3844 auth_defer_msg = expand_string_message;
3848 if (set_id) authenticated_fail_id = string_copy_perm(set_id, TRUE);
3849 *smtp_resp = string_sprintf("435 Unable to authenticate at present%s",
3850 auth_defer_user_msg);
3851 *errmsg = string_sprintf("435 Unable to authenticate at present%s: %s",
3852 set_id, auth_defer_msg);
3856 *smtp_resp = *errmsg = US"501 Invalid base64 data";
3860 *smtp_resp = *errmsg = US"501 Authentication cancelled";
3864 *smtp_resp = *errmsg = US"553 Initial data not expected";
3868 if (set_id) authenticated_fail_id = string_copy_perm(set_id, TRUE);
3869 *smtp_resp = US"535 Incorrect authentication data";
3870 *errmsg = string_sprintf("535 Incorrect authentication data%s", set_id);
3874 if (set_id) authenticated_fail_id = string_copy_perm(set_id, TRUE);
3875 *smtp_resp = US"435 Internal error";
3876 *errmsg = string_sprintf("435 Internal error%s: return %d from authentication "
3877 "check", set_id, rc);
3889 qualify_recipient(uschar ** recipient, uschar * smtp_cmd_data, uschar * tag)
3892 if (f.allow_unqualified_recipient || strcmpic(*recipient, US"postmaster") == 0)
3894 DEBUG(D_receive) debug_printf("unqualified address %s accepted\n",
3896 rd = Ustrlen(recipient) + 1;
3897 /* deconst ok as *recipient was not const */
3898 *recipient = US rewrite_address_qualify(*recipient, TRUE);
3901 smtp_printf("501 %s: recipient address must contain a domain\r\n", FALSE,
3903 log_write(L_smtp_syntax_error,
3904 LOG_MAIN|LOG_REJECT, "unqualified %s rejected: <%s> %s%s",
3905 tag, *recipient, host_and_ident(TRUE), host_lookup_msg);
3913 smtp_quit_handler(uschar ** user_msgp, uschar ** log_msgp)
3916 f.smtp_in_quit = TRUE;
3917 incomplete_transaction_log(US"QUIT");
3919 && acl_check(ACL_WHERE_QUIT, NULL, acl_smtp_quit, user_msgp, log_msgp)
3921 log_write(0, LOG_MAIN|LOG_PANIC, "ACL for QUIT returned ERROR: %s",
3924 #ifdef EXIM_TCP_CORK
3925 (void) setsockopt(fileno(smtp_out), IPPROTO_TCP, EXIM_TCP_CORK, US &on, sizeof(on));
3929 smtp_respond(US"221", 3, TRUE, *user_msgp);
3931 smtp_printf("221 %s closing connection\r\n", FALSE, smtp_active_hostname);
3933 #ifdef SERVERSIDE_CLOSE_NOWAIT
3934 # ifndef DISABLE_TLS
3935 tls_close(NULL, TLS_SHUTDOWN_NOWAIT);
3938 log_write(L_smtp_connection, LOG_MAIN, "%s closed by QUIT",
3939 smtp_get_connection_info());
3942 # ifndef DISABLE_TLS
3943 tls_close(NULL, TLS_SHUTDOWN_WAIT);
3946 log_write(L_smtp_connection, LOG_MAIN, "%s closed by QUIT",
3947 smtp_get_connection_info());
3949 /* Pause, hoping client will FIN first so that they get the TIME_WAIT.
3950 The socket should become readble (though with no data) */
3952 (void) poll_one_fd(fileno(smtp_in), POLLIN, 200);
3953 #endif /*!SERVERSIDE_CLOSE_NOWAIT*/
3958 smtp_rset_handler(void)
3961 incomplete_transaction_log(US"RSET");
3962 smtp_printf("250 Reset OK\r\n", FALSE);
3963 cmd_list[CMD_LIST_RSET].is_mail_cmd = FALSE;
3964 if (chunking_state > CHUNKING_OFFERED)
3965 chunking_state = CHUNKING_OFFERED;
3970 expand_mailmax(const uschar * s)
3972 if (!(s = expand_cstring(s)))
3973 log_write(0, LOG_MAIN|LOG_PANIC, "failed to expand smtp_accept_max_per_connection");
3974 return *s ? Uatoi(s) : 0;
3977 /*************************************************
3978 * Initialize for SMTP incoming message *
3979 *************************************************/
3981 /* This function conducts the initial dialogue at the start of an incoming SMTP
3982 message, and builds a list of recipients. However, if the incoming message
3983 is part of a batch (-bS option) a separate function is called since it would
3984 be messy having tests splattered about all over this function. This function
3985 therefore handles the case where interaction is occurring. The input and output
3986 files are set up in smtp_in and smtp_out.
3988 The global recipients_list is set to point to a vector of recipient_item
3989 blocks, whose number is given by recipients_count. This is extended by the
3990 receive_add_recipient() function. The global variable sender_address is set to
3991 the sender's address. The yield is +1 if a message has been successfully
3992 started, 0 if a QUIT command was encountered or the connection was refused from
3993 the particular host, or -1 if the connection was lost.
3997 Returns: > 0 message successfully started (reached DATA)
3998 = 0 QUIT read or end of file reached or call refused
4003 smtp_setup_msg(void)
4006 BOOL toomany = FALSE;
4007 BOOL discarded = FALSE;
4008 BOOL last_was_rej_mail = FALSE;
4009 BOOL last_was_rcpt = FALSE;
4010 rmark reset_point = store_mark();
4012 DEBUG(D_receive) debug_printf("smtp_setup_msg entered\n");
4014 /* Reset for start of new message. We allow one RSET not to be counted as a
4015 nonmail command, for those MTAs that insist on sending it between every
4016 message. Ditto for EHLO/HELO and for STARTTLS, to allow for going in and out of
4017 TLS between messages (an Exim client may do this if it has messages queued up
4018 for the host). Note: we do NOT reset AUTH at this point. */
4020 reset_point = smtp_reset(reset_point);
4021 message_ended = END_NOTSTARTED;
4023 chunking_state = f.chunking_offered ? CHUNKING_OFFERED : CHUNKING_NOT_OFFERED;
4025 cmd_list[CMD_LIST_RSET].is_mail_cmd = TRUE;
4026 cmd_list[CMD_LIST_HELO].is_mail_cmd = TRUE;
4027 cmd_list[CMD_LIST_EHLO].is_mail_cmd = TRUE;
4029 cmd_list[CMD_LIST_STARTTLS].is_mail_cmd = TRUE;
4032 if (lwr_receive_getc != NULL)
4034 /* This should have already happened, but if we've gotten confused,
4035 force a reset here. */
4036 DEBUG(D_receive) debug_printf("WARNING: smtp_setup_msg had to restore receive functions to lowers\n");
4037 bdat_pop_receive_functions();
4040 /* Set the local signal handler for SIGTERM - it tries to end off tidily */
4042 had_command_sigterm = 0;
4043 os_non_restarting_signal(SIGTERM, command_sigterm_handler);
4045 /* Batched SMTP is handled in a different function. */
4047 if (smtp_batched_input) return smtp_setup_batch_msg();
4050 if (smtp_in) /* Avoid pure-ACKs while in cmd pingpong phase */
4051 (void) setsockopt(fileno(smtp_in), IPPROTO_TCP, TCP_QUICKACK,
4052 US &off, sizeof(off));
4055 /* Deal with SMTP commands. This loop is exited by setting done to a POSITIVE
4056 value. The values are 2 larger than the required yield of the function. */
4060 const uschar **argv;
4061 uschar *etrn_command;
4062 uschar *etrn_serialize_key;
4064 uschar *log_msg, *smtp_code;
4065 uschar *user_msg = NULL;
4066 uschar *recipient = NULL;
4067 uschar *hello = NULL;
4069 BOOL was_rej_mail = FALSE;
4070 BOOL was_rcpt = FALSE;
4071 void (*oldsignal)(int);
4073 int start, end, sender_domain, recipient_domain;
4076 uschar *orcpt = NULL;
4081 /* Check once per STARTTLS or SSL-on-connect for a TLS AUTH */
4082 if ( tls_in.active.sock >= 0
4084 && tls_in.certificate_verified
4085 && cmd_list[CMD_LIST_TLS_AUTH].is_mail_cmd
4088 cmd_list[CMD_LIST_TLS_AUTH].is_mail_cmd = FALSE;
4090 for (auth_instance * au = auths; au; au = au->next)
4091 if (strcmpic(US"tls", au->driver_name) == 0)
4094 && (rc = acl_check(ACL_WHERE_AUTH, NULL, acl_smtp_auth,
4095 &user_msg, &log_msg)) != OK
4097 done = smtp_handle_acl_fail(ACL_WHERE_AUTH, rc, user_msg, log_msg);
4100 smtp_cmd_data = NULL;
4102 if (smtp_in_auth(au, &s, &ss) == OK)
4103 { DEBUG(D_auth) debug_printf("tls auth succeeded\n"); }
4106 DEBUG(D_auth) debug_printf("tls auth not succeeded\n");
4107 #ifndef DISABLE_EVENT
4109 uschar * save_name = sender_host_authenticated, * logmsg;
4110 sender_host_authenticated = au->name;
4111 if ((logmsg = event_raise(event_action, US"auth:fail", s, NULL)))
4112 log_write(0, LOG_MAIN, "%s", logmsg);
4113 sender_host_authenticated = save_name;
4123 switch(smtp_read_command(
4124 #ifndef DISABLE_PIPE_CONNECT
4125 !fl.pipe_connect_acceptable,
4129 GETC_BUFFER_UNLIMITED))
4131 /* The AUTH command is not permitted to occur inside a transaction, and may
4132 occur successfully only once per connection. Actually, that isn't quite
4133 true. When TLS is started, all previous information about a connection must
4134 be discarded, so a new AUTH is permitted at that time.
4136 AUTH may only be used when it has been advertised. However, it seems that
4137 there are clients that send AUTH when it hasn't been advertised, some of
4138 them even doing this after HELO. And there are MTAs that accept this. Sigh.
4139 So there's a get-out that allows this to happen.
4141 AUTH is initially labelled as a "nonmail command" so that one occurrence
4142 doesn't get counted. We change the label here so that multiple failing
4143 AUTHS will eventually hit the nonmail threshold. */
4147 authentication_failed = TRUE;
4148 cmd_list[CMD_LIST_AUTH].is_mail_cmd = FALSE;
4150 if (!fl.auth_advertised && !f.allow_auth_unadvertised)
4152 done = synprot_error(L_smtp_protocol_error, 503, NULL,
4153 US"AUTH command used when not advertised");
4156 if (sender_host_authenticated)
4158 done = synprot_error(L_smtp_protocol_error, 503, NULL,
4159 US"already authenticated");
4164 done = synprot_error(L_smtp_protocol_error, 503, NULL,
4165 US"not permitted in mail transaction");
4172 && (rc = acl_check(ACL_WHERE_AUTH, NULL, acl_smtp_auth,
4173 &user_msg, &log_msg)) != OK
4176 done = smtp_handle_acl_fail(ACL_WHERE_AUTH, rc, user_msg, log_msg);
4180 /* Find the name of the requested authentication mechanism. */
4183 for (; (c = *smtp_cmd_data) && !isspace(c); smtp_cmd_data++)
4184 if (!isalnum(c) && c != '-' && c != '_')
4186 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4187 US"invalid character in authentication mechanism name");
4191 /* If not at the end of the line, we must be at white space. Terminate the
4192 name and move the pointer on to any data that may be present. */
4196 *smtp_cmd_data++ = 0;
4197 while (isspace(*smtp_cmd_data)) smtp_cmd_data++;
4200 /* Search for an authentication mechanism which is configured for use
4201 as a server and which has been advertised (unless, sigh, allow_auth_
4202 unadvertised is set). */
4206 uschar * smtp_resp, * errmsg;
4208 for (au = auths; au; au = au->next)
4209 if (strcmpic(s, au->public_name) == 0 && au->server &&
4210 (au->advertised || f.allow_auth_unadvertised))
4215 int rc = smtp_in_auth(au, &smtp_resp, &errmsg);
4217 smtp_printf("%s\r\n", FALSE, smtp_resp);
4220 uschar * logmsg = NULL;
4221 #ifndef DISABLE_EVENT
4222 {uschar * save_name = sender_host_authenticated;
4223 sender_host_authenticated = au->name;
4224 logmsg = event_raise(event_action, US"auth:fail", smtp_resp, NULL);
4225 sender_host_authenticated = save_name;
4229 log_write(0, LOG_MAIN|LOG_REJECT, "%s", logmsg);
4231 log_write(0, LOG_MAIN|LOG_REJECT, "%s authenticator failed for %s: %s",
4232 au->name, host_and_ident(FALSE), errmsg);
4236 done = synprot_error(L_smtp_protocol_error, 504, NULL,
4237 string_sprintf("%s authentication mechanism not supported", s));
4240 break; /* AUTH_CMD */
4242 /* The HELO/EHLO commands are permitted to appear in the middle of a
4243 session as well as at the beginning. They have the effect of a reset in
4244 addition to their other functions. Their absence at the start cannot be
4245 taken to be an error.
4249 If the EHLO command is not acceptable to the SMTP server, 501, 500,
4250 or 502 failure replies MUST be returned as appropriate. The SMTP
4251 server MUST stay in the same state after transmitting these replies
4252 that it was in before the EHLO was received.
4254 Therefore, we do not do the reset until after checking the command for
4255 acceptability. This change was made for Exim release 4.11. Previously
4256 it did the reset first. */
4269 HELO_EHLO: /* Common code for HELO and EHLO */
4270 cmd_list[CMD_LIST_HELO].is_mail_cmd = FALSE;
4271 cmd_list[CMD_LIST_EHLO].is_mail_cmd = FALSE;
4273 /* Reject the HELO if its argument was invalid or non-existent. A
4274 successful check causes the argument to be saved in malloc store. */
4276 if (!check_helo(smtp_cmd_data))
4278 smtp_printf("501 Syntactically invalid %s argument(s)\r\n", FALSE, hello);
4280 log_write(0, LOG_MAIN|LOG_REJECT, "rejected %s from %s: syntactically "
4281 "invalid argument(s): %s", hello, host_and_ident(FALSE),
4282 *smtp_cmd_argument == 0 ? US"(no argument given)" :
4283 string_printing(smtp_cmd_argument));
4285 if (++synprot_error_count > smtp_max_synprot_errors)
4287 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
4288 "syntax or protocol errors (last command was \"%s\", %s)",
4289 host_and_ident(FALSE), string_printing(smtp_cmd_buffer),
4290 string_from_gstring(s_connhad_log(NULL))
4298 /* If sender_host_unknown is true, we have got here via the -bs interface,
4299 not called from inetd. Otherwise, we are running an IP connection and the
4300 host address will be set. If the helo name is the primary name of this
4301 host and we haven't done a reverse lookup, force one now. If helo_verify_required
4302 is set, ensure that the HELO name matches the actual host. If helo_verify
4303 is set, do the same check, but softly. */
4305 if (!f.sender_host_unknown)
4307 BOOL old_helo_verified = f.helo_verified;
4308 uschar *p = smtp_cmd_data;
4310 while (*p != 0 && !isspace(*p)) { *p = tolower(*p); p++; }
4313 /* Force a reverse lookup if HELO quoted something in helo_lookup_domains
4314 because otherwise the log can be confusing. */
4316 if ( !sender_host_name
4317 && match_isinlist(sender_helo_name, CUSS &helo_lookup_domains, 0,
4318 &domainlist_anchor, NULL, MCL_DOMAIN, TRUE, NULL) == OK)
4319 (void)host_name_lookup();
4321 /* Rebuild the fullhost info to include the HELO name (and the real name
4322 if it was looked up.) */
4324 host_build_sender_fullhost(); /* Rebuild */
4325 set_process_info("handling%s incoming connection from %s",
4326 tls_in.active.sock >= 0 ? " TLS" : "", host_and_ident(FALSE));
4328 /* Verify if configured. This doesn't give much security, but it does
4329 make some people happy to be able to do it. If helo_verify_required is set,
4330 (host matches helo_verify_hosts) failure forces rejection. If helo_verify
4331 is set (host matches helo_try_verify_hosts), it does not. This is perhaps
4332 now obsolescent, since the verification can now be requested selectively
4335 f.helo_verified = f.helo_verify_failed = sender_helo_dnssec = FALSE;
4336 if (fl.helo_verify_required || fl.helo_verify)
4338 BOOL tempfail = !smtp_verify_helo();
4339 if (!f.helo_verified)
4341 if (fl.helo_verify_required)
4343 smtp_printf("%d %s argument does not match calling host\r\n", FALSE,
4344 tempfail? 451 : 550, hello);
4345 log_write(0, LOG_MAIN|LOG_REJECT, "%srejected \"%s %s\" from %s",
4346 tempfail? "temporarily " : "",
4347 hello, sender_helo_name, host_and_ident(FALSE));
4348 f.helo_verified = old_helo_verified;
4349 break; /* End of HELO/EHLO processing */
4351 HDEBUG(D_all) debug_printf("%s verification failed but host is in "
4352 "helo_try_verify_hosts\n", hello);
4358 /* set up SPF context */
4359 spf_conn_init(sender_helo_name, sender_host_address);
4362 /* Apply an ACL check if one is defined; afterwards, recheck
4363 synchronization in case the client started sending in a delay. */
4366 if ((rc = acl_check(ACL_WHERE_HELO, NULL, acl_smtp_helo,
4367 &user_msg, &log_msg)) != OK)
4369 done = smtp_handle_acl_fail(ACL_WHERE_HELO, rc, user_msg, log_msg);
4370 sender_helo_name = NULL;
4371 host_build_sender_fullhost(); /* Rebuild */
4374 #ifndef DISABLE_PIPE_CONNECT
4375 else if (!fl.pipe_connect_acceptable && !check_sync())
4377 else if (!check_sync())
4381 /* Generate an OK reply. The default string includes the ident if present,
4382 and also the IP address if present. Reflecting back the ident is intended
4383 as a deterrent to mail forgers. For maximum efficiency, and also because
4384 some broken systems expect each response to be in a single packet, arrange
4385 that the entire reply is sent in one write(). */
4387 fl.auth_advertised = FALSE;
4388 f.smtp_in_pipelining_advertised = FALSE;
4390 fl.tls_advertised = FALSE;
4392 fl.dsn_advertised = FALSE;
4394 fl.smtputf8_advertised = FALSE;
4397 /* Expand the per-connection message count limit option */
4398 smtp_mailcmd_max = expand_mailmax(smtp_accept_max_per_connection);
4400 smtp_code = US"250 "; /* Default response code plus space*/
4403 /* sender_host_name below will be tainted, so save on copy when we hit it */
4404 g = string_get_tainted(24, GET_TAINTED);
4405 g = string_fmt_append(g, "%.3s %s Hello %s%s%s",
4407 smtp_active_hostname,
4408 sender_ident ? sender_ident : US"",
4409 sender_ident ? US" at " : US"",
4410 sender_host_name ? sender_host_name : sender_helo_name);
4412 if (sender_host_address)
4413 g = string_fmt_append(g, " [%s]", sender_host_address);
4416 /* A user-supplied EHLO greeting may not contain more than one line. Note
4417 that the code returned by smtp_message_code() includes the terminating
4418 whitespace character. */
4424 smtp_message_code(&smtp_code, &codelen, &user_msg, NULL, TRUE);
4425 s = string_sprintf("%.*s%s", codelen, smtp_code, user_msg);
4426 if ((ss = strpbrk(CS s, "\r\n")) != NULL)
4428 log_write(0, LOG_MAIN|LOG_PANIC, "EHLO/HELO response must not contain "
4429 "newlines: message truncated: %s", string_printing(s));
4432 g = string_cat(NULL, s);
4435 g = string_catn(g, US"\r\n", 2);
4437 /* If we received EHLO, we must create a multiline response which includes
4438 the functions supported. */
4444 /* I'm not entirely happy with this, as an MTA is supposed to check
4445 that it has enough room to accept a message of maximum size before
4446 it sends this. However, there seems little point in not sending it.
4447 The actual size check happens later at MAIL FROM time. By postponing it
4448 till then, VRFY and EXPN can be used after EHLO when space is short. */
4450 if (thismessage_size_limit > 0)
4451 g = string_fmt_append(g, "%.3s-SIZE %d\r\n", smtp_code,
4452 thismessage_size_limit);
4455 g = string_catn(g, smtp_code, 3);
4456 g = string_catn(g, US"-SIZE\r\n", 7);
4459 #ifdef EXPERIMENTAL_ESMTP_LIMITS
4460 if ( (smtp_mailcmd_max > 0 || recipients_max)
4461 && verify_check_host(&limits_advertise_hosts) == OK)
4463 g = string_fmt_append(g, "%.3s-LIMITS", smtp_code);
4464 if (smtp_mailcmd_max > 0)
4465 g = string_fmt_append(g, " MAILMAX=%d", smtp_mailcmd_max);
4467 g = string_fmt_append(g, " RCPTMAX=%d", recipients_max);
4468 g = string_catn(g, US"\r\n", 2);
4472 /* Exim does not do protocol conversion or data conversion. It is 8-bit
4473 clean; if it has an 8-bit character in its hand, it just sends it. It
4474 cannot therefore specify 8BITMIME and remain consistent with the RFCs.
4475 However, some users want this option simply in order to stop MUAs
4476 mangling messages that contain top-bit-set characters. It is therefore
4477 provided as an option. */
4479 if (accept_8bitmime)
4481 g = string_catn(g, smtp_code, 3);
4482 g = string_catn(g, US"-8BITMIME\r\n", 11);
4485 /* Advertise DSN support if configured to do so. */
4486 if (verify_check_host(&dsn_advertise_hosts) != FAIL)
4488 g = string_catn(g, smtp_code, 3);
4489 g = string_catn(g, US"-DSN\r\n", 6);
4490 fl.dsn_advertised = TRUE;
4493 /* Advertise ETRN/VRFY/EXPN if there's are ACL checking whether a host is
4494 permitted to issue them; a check is made when any host actually tries. */
4498 g = string_catn(g, smtp_code, 3);
4499 g = string_catn(g, US"-ETRN\r\n", 7);
4503 g = string_catn(g, smtp_code, 3);
4504 g = string_catn(g, US"-VRFY\r\n", 7);
4508 g = string_catn(g, smtp_code, 3);
4509 g = string_catn(g, US"-EXPN\r\n", 7);
4512 /* Exim is quite happy with pipelining, so let the other end know that
4513 it is safe to use it, unless advertising is disabled. */
4515 if ( f.pipelining_enable
4516 && verify_check_host(&pipelining_advertise_hosts) == OK)
4518 g = string_catn(g, smtp_code, 3);
4519 g = string_catn(g, US"-PIPELINING\r\n", 13);
4520 sync_cmd_limit = NON_SYNC_CMD_PIPELINING;
4521 f.smtp_in_pipelining_advertised = TRUE;
4523 #ifndef DISABLE_PIPE_CONNECT
4524 if (fl.pipe_connect_acceptable)
4526 f.smtp_in_early_pipe_advertised = TRUE;
4527 g = string_catn(g, smtp_code, 3);
4528 g = string_catn(g, US"-" EARLY_PIPE_FEATURE_NAME "\r\n", EARLY_PIPE_FEATURE_LEN+3);
4534 /* If any server authentication mechanisms are configured, advertise
4535 them if the current host is in auth_advertise_hosts. The problem with
4536 advertising always is that some clients then require users to
4537 authenticate (and aren't configurable otherwise) even though it may not
4538 be necessary (e.g. if the host is in host_accept_relay).
4540 RFC 2222 states that SASL mechanism names contain only upper case
4541 letters, so output the names in upper case, though we actually recognize
4542 them in either case in the AUTH command. */
4546 && !sender_host_authenticated
4548 && verify_check_host(&auth_advertise_hosts) == OK
4552 for (auth_instance * au = auths; au; au = au->next)
4554 au->advertised = FALSE;
4557 DEBUG(D_auth+D_expand) debug_printf_indent(
4558 "Evaluating advertise_condition for %s %s athenticator\n",
4559 au->name, au->public_name);
4560 if ( !au->advertise_condition
4561 || expand_check_condition(au->advertise_condition, au->name,
4568 g = string_catn(g, smtp_code, 3);
4569 g = string_catn(g, US"-AUTH", 5);
4571 fl.auth_advertised = TRUE;
4574 g = string_catn(g, US" ", 1);
4575 g = string_cat (g, au->public_name);
4576 while (++saveptr < g->ptr) g->s[saveptr] = toupper(g->s[saveptr]);
4577 au->advertised = TRUE;
4582 if (!first) g = string_catn(g, US"\r\n", 2);
4585 /* RFC 3030 CHUNKING */
4587 if (verify_check_host(&chunking_advertise_hosts) != FAIL)
4589 g = string_catn(g, smtp_code, 3);
4590 g = string_catn(g, US"-CHUNKING\r\n", 11);
4591 f.chunking_offered = TRUE;
4592 chunking_state = CHUNKING_OFFERED;
4595 /* Advertise TLS (Transport Level Security) aka SSL (Secure Socket Layer)
4596 if it has been included in the binary, and the host matches
4597 tls_advertise_hosts. We must *not* advertise if we are already in a
4598 secure connection. */
4601 if (tls_in.active.sock < 0 &&
4602 verify_check_host(&tls_advertise_hosts) != FAIL)
4604 g = string_catn(g, smtp_code, 3);
4605 g = string_catn(g, US"-STARTTLS\r\n", 11);
4606 fl.tls_advertised = TRUE;
4610 #ifndef DISABLE_PRDR
4611 /* Per Recipient Data Response, draft by Eric A. Hall extending RFC */
4614 g = string_catn(g, smtp_code, 3);
4615 g = string_catn(g, US"-PRDR\r\n", 7);
4620 if ( accept_8bitmime
4621 && verify_check_host(&smtputf8_advertise_hosts) != FAIL)
4623 g = string_catn(g, smtp_code, 3);
4624 g = string_catn(g, US"-SMTPUTF8\r\n", 11);
4625 fl.smtputf8_advertised = TRUE;
4629 /* Finish off the multiline reply with one that is always available. */
4631 g = string_catn(g, smtp_code, 3);
4632 g = string_catn(g, US" HELP\r\n", 7);
4635 /* Terminate the string (for debug), write it, and note that HELO/EHLO
4639 if (tls_in.active.sock >= 0)
4640 (void)tls_write(NULL, g->s, g->ptr,
4641 # ifndef DISABLE_PIPE_CONNECT
4642 fl.pipe_connect_acceptable && pipeline_connect_sends());
4648 (void) fwrite(g->s, 1, g->ptr, smtp_out);
4650 DEBUG(D_receive) for (const uschar * t, * s = string_from_gstring(g);
4651 s && (t = Ustrchr(s, '\r'));
4652 s = t + 2) /* \r\n */
4653 debug_printf("%s %.*s\n",
4654 s == g->s ? "SMTP>>" : " ",
4656 fl.helo_seen = TRUE;
4658 /* Reset the protocol and the state, abandoning any previous message. */
4660 (sender_host_address ? protocols : protocols_local)
4662 ? pextend + (sender_host_authenticated ? pauthed : 0)
4664 + (tls_in.active.sock >= 0 ? pcrpted : 0)
4666 cancel_cutthrough_connection(TRUE, US"sent EHLO response");
4667 reset_point = smtp_reset(reset_point);
4669 break; /* HELO/EHLO */
4672 /* The MAIL command requires an address as an operand. All we do
4673 here is to parse it for syntactic correctness. The form "<>" is
4674 a special case which converts into an empty string. The start/end
4675 pointers in the original are not used further for this address, as
4676 it is the canonical extracted address which is all that is kept. */
4680 smtp_mailcmd_count++; /* Count for limit and ratelimit */
4682 was_rej_mail = TRUE; /* Reset if accepted */
4683 env_mail_type_t * mail_args; /* Sanity check & validate args */
4686 if ( fl.helo_verify_required
4687 || verify_check_host(&hosts_require_helo) == OK)
4689 smtp_printf("503 HELO or EHLO required\r\n", FALSE);
4690 log_write(0, LOG_MAIN|LOG_REJECT, "rejected MAIL from %s: no "
4691 "HELO/EHLO given", host_and_ident(FALSE));
4694 else if (smtp_mailcmd_max < 0)
4695 smtp_mailcmd_max = expand_mailmax(smtp_accept_max_per_connection);
4699 done = synprot_error(L_smtp_protocol_error, 503, NULL,
4700 US"sender already given");
4704 if (!*smtp_cmd_data)
4706 done = synprot_error(L_smtp_protocol_error, 501, NULL,
4707 US"MAIL must have an address operand");
4711 /* Check to see if the limit for messages per connection would be
4712 exceeded by accepting further messages. */
4714 if (smtp_mailcmd_max > 0 && smtp_mailcmd_count > smtp_mailcmd_max)
4716 smtp_printf("421 too many messages in this connection\r\n", FALSE);
4717 log_write(0, LOG_MAIN|LOG_REJECT, "rejected MAIL command %s: too many "
4718 "messages in one connection", host_and_ident(TRUE));
4722 /* Reset for start of message - even if this is going to fail, we
4723 obviously need to throw away any previous data. */
4725 cancel_cutthrough_connection(TRUE, US"MAIL received");
4726 reset_point = smtp_reset(reset_point);
4728 sender_data = recipient_data = NULL;
4730 /* Loop, checking for ESMTP additions to the MAIL FROM command. */
4732 if (fl.esmtp) for(;;)
4734 uschar *name, *value, *end;
4735 unsigned long int size;
4736 BOOL arg_error = FALSE;
4738 if (!extract_option(&name, &value)) break;
4740 for (mail_args = env_mail_type_list;
4741 mail_args->value != ENV_MAIL_OPT_NULL;
4744 if (strcmpic(name, mail_args->name) == 0)
4746 if (mail_args->need_value && strcmpic(value, US"") == 0)
4749 switch(mail_args->value)
4751 /* Handle SIZE= by reading the value. We don't do the check till later,
4752 in order to be able to log the sender address on failure. */
4753 case ENV_MAIL_OPT_SIZE:
4754 if (((size = Ustrtoul(value, &end, 10)), *end == 0))
4756 if ((size == ULONG_MAX && errno == ERANGE) || size > INT_MAX)
4758 message_size = (int)size;
4764 /* If this session was initiated with EHLO and accept_8bitmime is set,
4765 Exim will have indicated that it supports the BODY=8BITMIME option. In
4766 fact, it does not support this according to the RFCs, in that it does not
4767 take any special action for forwarding messages containing 8-bit
4768 characters. That is why accept_8bitmime is not the default setting, but
4769 some sites want the action that is provided. We recognize both "8BITMIME"
4770 and "7BIT" as body types, but take no action. */
4771 case ENV_MAIL_OPT_BODY:
4772 if (accept_8bitmime) {
4773 if (strcmpic(value, US"8BITMIME") == 0)
4775 else if (strcmpic(value, US"7BIT") == 0)
4780 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4781 US"invalid data for BODY");
4784 DEBUG(D_receive) debug_printf("8BITMIME: %d\n", body_8bitmime);
4790 /* Handle the two DSN options, but only if configured to do so (which
4791 will have caused "DSN" to be given in the EHLO response). The code itself
4792 is included only if configured in at build time. */
4794 case ENV_MAIL_OPT_RET:
4795 if (fl.dsn_advertised)
4797 /* Check if RET has already been set */
4800 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4801 US"RET can be specified once only");
4804 dsn_ret = strcmpic(value, US"HDRS") == 0
4806 : strcmpic(value, US"FULL") == 0
4809 DEBUG(D_receive) debug_printf("DSN_RET: %d\n", dsn_ret);
4810 /* Check for invalid invalid value, and exit with error */
4813 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4814 US"Value for RET is invalid");
4819 case ENV_MAIL_OPT_ENVID:
4820 if (fl.dsn_advertised)
4822 /* Check if the dsn envid has been already set */
4825 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4826 US"ENVID can be specified once only");
4829 dsn_envid = string_copy(value);
4830 DEBUG(D_receive) debug_printf("DSN_ENVID: %s\n", dsn_envid);
4834 /* Handle the AUTH extension. If the value given is not "<>" and either
4835 the ACL says "yes" or there is no ACL but the sending host is
4836 authenticated, we set it up as the authenticated sender. However, if the
4837 authenticator set a condition to be tested, we ignore AUTH on MAIL unless
4838 the condition is met. The value of AUTH is an xtext, which means that +,
4839 = and cntrl chars are coded in hex; however "<>" is unaffected by this
4841 case ENV_MAIL_OPT_AUTH:
4842 if (Ustrcmp(value, "<>") != 0)
4847 if (auth_xtextdecode(value, &authenticated_sender) < 0)
4849 /* Put back terminator overrides for error message */
4852 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4853 US"invalid data for AUTH");
4856 if (!acl_smtp_mailauth)
4858 ignore_msg = US"client not authenticated";
4859 rc = sender_host_authenticated ? OK : FAIL;
4863 ignore_msg = US"rejected by ACL";
4864 rc = acl_check(ACL_WHERE_MAILAUTH, NULL, acl_smtp_mailauth,
4865 &user_msg, &log_msg);
4871 if (authenticated_by == NULL ||
4872 authenticated_by->mail_auth_condition == NULL ||
4873 expand_check_condition(authenticated_by->mail_auth_condition,
4874 authenticated_by->name, US"authenticator"))
4875 break; /* Accept the AUTH */
4877 ignore_msg = US"server_mail_auth_condition failed";
4878 if (authenticated_id != NULL)
4879 ignore_msg = string_sprintf("%s: authenticated ID=\"%s\"",
4880 ignore_msg, authenticated_id);
4885 authenticated_sender = NULL;
4886 log_write(0, LOG_MAIN, "ignoring AUTH=%s from %s (%s)",
4887 value, host_and_ident(TRUE), ignore_msg);
4890 /* Should only get DEFER or ERROR here. Put back terminator
4891 overrides for error message */
4896 (void)smtp_handle_acl_fail(ACL_WHERE_MAILAUTH, rc, user_msg,
4903 #ifndef DISABLE_PRDR
4904 case ENV_MAIL_OPT_PRDR:
4906 prdr_requested = TRUE;
4911 case ENV_MAIL_OPT_UTF8:
4912 if (!fl.smtputf8_advertised)
4914 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4915 US"SMTPUTF8 used when not advertised");
4919 DEBUG(D_receive) debug_printf("smtputf8 requested\n");
4920 message_smtputf8 = allow_utf8_domains = TRUE;
4921 if (Ustrncmp(received_protocol, US"utf8", 4) != 0)
4923 int old_pool = store_pool;
4924 store_pool = POOL_PERM;
4925 received_protocol = string_sprintf("utf8%s", received_protocol);
4926 store_pool = old_pool;
4931 /* No valid option. Stick back the terminator characters and break
4932 the loop. Do the name-terminator second as extract_option sets
4933 value==name when it found no equal-sign.
4934 An error for a malformed address will occur. */
4935 case ENV_MAIL_OPT_NULL:
4943 /* Break out of for loop if switch() had bad argument or
4944 when start of the email address is reached */
4945 if (arg_error) break;
4948 /* If we have passed the threshold for rate limiting, apply the current
4949 delay, and update it for next time, provided this is a limited host. */
4951 if (smtp_mailcmd_count > smtp_rlm_threshold &&
4952 verify_check_host(&smtp_ratelimit_hosts) == OK)
4954 DEBUG(D_receive) debug_printf("rate limit MAIL: delay %.3g sec\n",
4955 smtp_delay_mail/1000.0);
4956 millisleep((int)smtp_delay_mail);
4957 smtp_delay_mail *= smtp_rlm_factor;
4958 if (smtp_delay_mail > (double)smtp_rlm_limit)
4959 smtp_delay_mail = (double)smtp_rlm_limit;
4962 /* Now extract the address, first applying any SMTP-time rewriting. The
4963 TRUE flag allows "<>" as a sender address. */
4965 raw_sender = rewrite_existflags & rewrite_smtp
4966 /* deconst ok as smtp_cmd_data was not const */
4967 ? US rewrite_one(smtp_cmd_data, rewrite_smtp, NULL, FALSE, US"",
4968 global_rewrite_rules)
4972 parse_extract_address(raw_sender, &errmess, &start, &end, &sender_domain,
4977 done = synprot_error(L_smtp_syntax_error, 501, smtp_cmd_data, errmess);
4981 sender_address = raw_sender;
4983 /* If there is a configured size limit for mail, check that this message
4984 doesn't exceed it. The check is postponed to this point so that the sender
4987 if (thismessage_size_limit > 0 && message_size > thismessage_size_limit)
4989 smtp_printf("552 Message size exceeds maximum permitted\r\n", FALSE);
4990 log_write(L_size_reject,
4991 LOG_MAIN|LOG_REJECT, "rejected MAIL FROM:<%s> %s: "
4992 "message too big: size%s=%d max=%d",
4994 host_and_ident(TRUE),
4995 (message_size == INT_MAX)? ">" : "",
4997 thismessage_size_limit);
4998 sender_address = NULL;
5002 /* Check there is enough space on the disk unless configured not to.
5003 When smtp_check_spool_space is set, the check is for thismessage_size_limit
5004 plus the current message - i.e. we accept the message only if it won't
5005 reduce the space below the threshold. Add 5000 to the size to allow for
5006 overheads such as the Received: line and storing of recipients, etc.
5007 By putting the check here, even when SIZE is not given, it allow VRFY
5008 and EXPN etc. to be used when space is short. */
5010 if (!receive_check_fs(
5011 smtp_check_spool_space && message_size >= 0
5012 ? message_size + 5000 : 0))
5014 smtp_printf("452 Space shortage, please try later\r\n", FALSE);
5015 sender_address = NULL;
5019 /* If sender_address is unqualified, reject it, unless this is a locally
5020 generated message, or the sending host or net is permitted to send
5021 unqualified addresses - typically local machines behaving as MUAs -
5022 in which case just qualify the address. The flag is set above at the start
5023 of the SMTP connection. */
5025 if (!sender_domain && *sender_address)
5026 if (f.allow_unqualified_sender)
5028 sender_domain = Ustrlen(sender_address) + 1;
5029 /* deconst ok as sender_address was not const */
5030 sender_address = US rewrite_address_qualify(sender_address, FALSE);
5031 DEBUG(D_receive) debug_printf("unqualified address %s accepted\n",
5036 smtp_printf("501 %s: sender address must contain a domain\r\n", FALSE,
5038 log_write(L_smtp_syntax_error,
5039 LOG_MAIN|LOG_REJECT,
5040 "unqualified sender rejected: <%s> %s%s",
5042 host_and_ident(TRUE),
5044 sender_address = NULL;
5048 /* Apply an ACL check if one is defined, before responding. Afterwards,
5049 when pipelining is not advertised, do another sync check in case the ACL
5050 delayed and the client started sending in the meantime. */
5054 rc = acl_check(ACL_WHERE_MAIL, NULL, acl_smtp_mail, &user_msg, &log_msg);
5055 if (rc == OK && !f.smtp_in_pipelining_advertised && !check_sync())
5061 if (rc == OK || rc == DISCARD)
5063 BOOL more = pipeline_response();
5066 smtp_printf("%s%s%s", more, US"250 OK",
5067 #ifndef DISABLE_PRDR
5068 prdr_requested ? US", PRDR Requested" : US"",
5075 #ifndef DISABLE_PRDR
5077 user_msg = string_sprintf("%s%s", user_msg, US", PRDR Requested");
5079 smtp_user_msg(US"250", user_msg);
5081 smtp_delay_rcpt = smtp_rlr_base;
5082 f.recipients_discarded = (rc == DISCARD);
5083 was_rej_mail = FALSE;
5087 done = smtp_handle_acl_fail(ACL_WHERE_MAIL, rc, user_msg, log_msg);
5088 sender_address = NULL;
5093 /* The RCPT command requires an address as an operand. There may be any
5094 number of RCPT commands, specifying multiple recipients. We build them all
5095 into a data structure. The start/end values given by parse_extract_address
5096 are not used, as we keep only the extracted address. */
5100 /* We got really to many recipients. A check against configured
5101 limits is done later */
5102 if (rcpt_count < 0 || rcpt_count >= INT_MAX/2)
5103 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "Too many recipients: %d", rcpt_count);
5105 was_rcpt = fl.rcpt_in_progress = TRUE;
5107 /* There must be a sender address; if the sender was rejected and
5108 pipelining was advertised, we assume the client was pipelining, and do not
5109 count this as a protocol error. Reset was_rej_mail so that further RCPTs
5110 get the same treatment. */
5112 if (!sender_address)
5114 if (f.smtp_in_pipelining_advertised && last_was_rej_mail)
5116 smtp_printf("503 sender not yet given\r\n", FALSE);
5117 was_rej_mail = TRUE;
5121 done = synprot_error(L_smtp_protocol_error, 503, NULL,
5122 US"sender not yet given");
5123 was_rcpt = FALSE; /* Not a valid RCPT */
5129 /* Check for an operand */
5131 if (!smtp_cmd_data[0])
5133 done = synprot_error(L_smtp_syntax_error, 501, NULL,
5134 US"RCPT must have an address operand");
5139 /* Set the DSN flags orcpt and dsn_flags from the session*/
5143 if (fl.esmtp) for(;;)
5145 uschar *name, *value;
5147 if (!extract_option(&name, &value))
5150 if (fl.dsn_advertised && strcmpic(name, US"ORCPT") == 0)
5152 /* Check whether orcpt has been already set */
5155 done = synprot_error(L_smtp_syntax_error, 501, NULL,
5156 US"ORCPT can be specified once only");
5159 orcpt = string_copy(value);
5160 DEBUG(D_receive) debug_printf("DSN orcpt: %s\n", orcpt);
5163 else if (fl.dsn_advertised && strcmpic(name, US"NOTIFY") == 0)
5165 /* Check if the notify flags have been already set */
5168 done = synprot_error(L_smtp_syntax_error, 501, NULL,
5169 US"NOTIFY can be specified once only");
5172 if (strcmpic(value, US"NEVER") == 0)
5173 dsn_flags |= rf_notify_never;
5180 while (*pp != 0 && *pp != ',') pp++;
5181 if (*pp == ',') *pp++ = 0;
5182 if (strcmpic(p, US"SUCCESS") == 0)
5184 DEBUG(D_receive) debug_printf("DSN: Setting notify success\n");
5185 dsn_flags |= rf_notify_success;
5187 else if (strcmpic(p, US"FAILURE") == 0)
5189 DEBUG(D_receive) debug_printf("DSN: Setting notify failure\n");
5190 dsn_flags |= rf_notify_failure;
5192 else if (strcmpic(p, US"DELAY") == 0)
5194 DEBUG(D_receive) debug_printf("DSN: Setting notify delay\n");
5195 dsn_flags |= rf_notify_delay;
5199 /* Catch any strange values */
5200 done = synprot_error(L_smtp_syntax_error, 501, NULL,
5201 US"Invalid value for NOTIFY parameter");
5206 DEBUG(D_receive) debug_printf("DSN Flags: %x\n", dsn_flags);
5210 /* Unknown option. Stick back the terminator characters and break
5211 the loop. An error for a malformed address will occur. */
5215 DEBUG(D_receive) debug_printf("Invalid RCPT option: %s : %s\n", name, value);
5222 /* Apply SMTP rewriting then extract the working address. Don't allow "<>"
5223 as a recipient address */
5225 recipient = rewrite_existflags & rewrite_smtp
5226 /* deconst ok as smtp_cmd_data was not const */
5227 ? US rewrite_one(smtp_cmd_data, rewrite_smtp, NULL, FALSE, US"",
5228 global_rewrite_rules)
5231 if (!(recipient = parse_extract_address(recipient, &errmess, &start, &end,
5232 &recipient_domain, FALSE)))
5234 done = synprot_error(L_smtp_syntax_error, 501, smtp_cmd_data, errmess);
5239 /* If the recipient address is unqualified, reject it, unless this is a
5240 locally generated message. However, unqualified addresses are permitted
5241 from a configured list of hosts and nets - typically when behaving as
5242 MUAs rather than MTAs. Sad that SMTP is used for both types of traffic,
5243 really. The flag is set at the start of the SMTP connection.
5245 RFC 1123 talks about supporting "the reserved mailbox postmaster"; I always
5246 assumed this meant "reserved local part", but the revision of RFC 821 and
5247 friends now makes it absolutely clear that it means *mailbox*. Consequently
5248 we must always qualify this address, regardless. */
5250 if (!recipient_domain)
5251 if (!(recipient_domain = qualify_recipient(&recipient, smtp_cmd_data,
5258 /* Check maximum allowed */
5260 if (rcpt_count+1 < 0 || rcpt_count > recipients_max && recipients_max > 0)
5262 if (recipients_max_reject)
5265 smtp_printf("552 too many recipients\r\n", FALSE);
5267 log_write(0, LOG_MAIN|LOG_REJECT, "too many recipients: message "
5268 "rejected: sender=<%s> %s", sender_address, host_and_ident(TRUE));
5273 smtp_printf("452 too many recipients\r\n", FALSE);
5275 log_write(0, LOG_MAIN|LOG_REJECT, "too many recipients: excess "
5276 "temporarily rejected: sender=<%s> %s", sender_address,
5277 host_and_ident(TRUE));
5284 /* If we have passed the threshold for rate limiting, apply the current
5285 delay, and update it for next time, provided this is a limited host. */
5287 if (rcpt_count > smtp_rlr_threshold &&
5288 verify_check_host(&smtp_ratelimit_hosts) == OK)
5290 DEBUG(D_receive) debug_printf("rate limit RCPT: delay %.3g sec\n",
5291 smtp_delay_rcpt/1000.0);
5292 millisleep((int)smtp_delay_rcpt);
5293 smtp_delay_rcpt *= smtp_rlr_factor;
5294 if (smtp_delay_rcpt > (double)smtp_rlr_limit)
5295 smtp_delay_rcpt = (double)smtp_rlr_limit;
5298 /* If the MAIL ACL discarded all the recipients, we bypass ACL checking
5299 for them. Otherwise, check the access control list for this recipient. As
5300 there may be a delay in this, re-check for a synchronization error
5301 afterwards, unless pipelining was advertised. */
5303 if (f.recipients_discarded)
5306 if ( (rc = acl_check(ACL_WHERE_RCPT, recipient, acl_smtp_rcpt, &user_msg,
5308 && !f.smtp_in_pipelining_advertised && !check_sync())
5311 /* The ACL was happy */
5315 BOOL more = pipeline_response();
5318 smtp_user_msg(US"250", user_msg);
5320 smtp_printf("250 Accepted\r\n", more);
5321 receive_add_recipient(recipient, -1);
5323 /* Set the dsn flags in the recipients_list */
5324 recipients_list[recipients_count-1].orcpt = orcpt;
5325 recipients_list[recipients_count-1].dsn_flags = dsn_flags;
5327 /* DEBUG(D_receive) debug_printf("DSN: orcpt: %s flags: %d\n",
5328 recipients_list[recipients_count-1].orcpt,
5329 recipients_list[recipients_count-1].dsn_flags); */
5332 /* The recipient was discarded */
5334 else if (rc == DISCARD)
5337 smtp_user_msg(US"250", user_msg);
5339 smtp_printf("250 Accepted\r\n", FALSE);
5342 log_write(0, LOG_MAIN|LOG_REJECT, "%s F=<%s> RCPT %s: "
5343 "discarded by %s ACL%s%s", host_and_ident(TRUE),
5344 sender_address_unrewritten ? sender_address_unrewritten : sender_address,
5345 smtp_cmd_argument, f.recipients_discarded ? "MAIL" : "RCPT",
5346 log_msg ? US": " : US"", log_msg ? log_msg : US"");
5349 /* Either the ACL failed the address, or it was deferred. */
5353 if (rc == FAIL) rcpt_fail_count++; else rcpt_defer_count++;
5354 done = smtp_handle_acl_fail(ACL_WHERE_RCPT, rc, user_msg, log_msg);
5359 /* The DATA command is legal only if it follows successful MAIL FROM
5360 and RCPT TO commands. However, if pipelining is advertised, a bad DATA is
5361 not counted as a protocol error if it follows RCPT (which must have been
5362 rejected if there are no recipients.) This function is complete when a
5363 valid DATA command is encountered.
5365 Note concerning the code used: RFC 2821 says this:
5367 - If there was no MAIL, or no RCPT, command, or all such commands
5368 were rejected, the server MAY return a "command out of sequence"
5369 (503) or "no valid recipients" (554) reply in response to the
5372 The example in the pipelining RFC 2920 uses 554, but I use 503 here
5373 because it is the same whether pipelining is in use or not.
5375 If all the RCPT commands that precede DATA provoked the same error message
5376 (often indicating some kind of system error), it is helpful to include it
5377 with the DATA rejection (an idea suggested by Tony Finch). */
5384 if (chunking_state != CHUNKING_OFFERED)
5386 done = synprot_error(L_smtp_protocol_error, 503, NULL,
5387 US"BDAT command used when CHUNKING not advertised");
5391 /* grab size, endmarker */
5393 if (sscanf(CS smtp_cmd_data, "%u %n", &chunking_datasize, &n) < 1)
5395 done = synprot_error(L_smtp_protocol_error, 501, NULL,
5396 US"missing size for BDAT command");
5399 chunking_state = strcmpic(smtp_cmd_data+n, US"LAST") == 0
5400 ? CHUNKING_LAST : CHUNKING_ACTIVE;
5401 chunking_data_left = chunking_datasize;
5402 DEBUG(D_receive) debug_printf("chunking state %d, %d bytes\n",
5403 (int)chunking_state, chunking_data_left);
5405 f.bdat_readers_wanted = TRUE; /* FIXME: redundant vs chunking_state? */
5414 f.bdat_readers_wanted = FALSE;
5416 DATA_BDAT: /* Common code for DATA and BDAT */
5417 #ifndef DISABLE_PIPE_CONNECT
5418 fl.pipe_connect_acceptable = FALSE;
5420 if (!discarded && recipients_count <= 0)
5422 if (fl.rcpt_smtp_response_same && rcpt_smtp_response)
5424 uschar *code = US"503";
5425 int len = Ustrlen(rcpt_smtp_response);
5426 smtp_respond(code, 3, FALSE, US"All RCPT commands were rejected with "
5428 /* Responses from smtp_printf() will have \r\n on the end */
5429 if (len > 2 && rcpt_smtp_response[len-2] == '\r')
5430 rcpt_smtp_response[len-2] = 0;
5431 smtp_respond(code, 3, FALSE, rcpt_smtp_response);
5433 if (f.smtp_in_pipelining_advertised && last_was_rcpt)
5434 smtp_printf("503 Valid RCPT command must precede %s\r\n", FALSE,
5435 smtp_names[smtp_connection_had[SMTP_HBUFF_PREV(smtp_ch_index)]]);
5437 done = synprot_error(L_smtp_protocol_error, 503, NULL,
5438 smtp_connection_had[SMTP_HBUFF_PREV(smtp_ch_index)] == SCH_DATA
5439 ? US"valid RCPT command must precede DATA"
5440 : US"valid RCPT command must precede BDAT");
5442 if (chunking_state > CHUNKING_OFFERED)
5444 bdat_push_receive_functions();
5450 if (toomany && recipients_max_reject)
5452 sender_address = NULL; /* This will allow a new MAIL without RSET */
5453 sender_address_unrewritten = NULL;
5454 smtp_printf("554 Too many recipients\r\n", FALSE);
5456 if (chunking_state > CHUNKING_OFFERED)
5458 bdat_push_receive_functions();
5464 if (chunking_state > CHUNKING_OFFERED)
5465 rc = OK; /* No predata ACL or go-ahead output for BDAT */
5468 /* If there is an ACL, re-check the synchronization afterwards, since the
5469 ACL may have delayed. To handle cutthrough delivery enforce a dummy call
5470 to get the DATA command sent. */
5472 if (!acl_smtp_predata && cutthrough.cctx.sock < 0)
5476 uschar * acl = acl_smtp_predata ? acl_smtp_predata : US"accept";
5477 f.enable_dollar_recipients = TRUE;
5478 rc = acl_check(ACL_WHERE_PREDATA, NULL, acl, &user_msg,
5480 f.enable_dollar_recipients = FALSE;
5481 if (rc == OK && !check_sync())
5485 { /* Either the ACL failed the address, or it was deferred. */
5486 done = smtp_handle_acl_fail(ACL_WHERE_PREDATA, rc, user_msg, log_msg);
5492 smtp_user_msg(US"354", user_msg);
5495 "354 Enter message, ending with \".\" on a line by itself\r\n", FALSE);
5498 if (f.bdat_readers_wanted)
5499 bdat_push_receive_functions();
5502 if (smtp_in) /* all ACKs needed to ramp window up for bulk data */
5503 (void) setsockopt(fileno(smtp_in), IPPROTO_TCP, TCP_QUICKACK,
5504 US &on, sizeof(on));
5507 message_ended = END_NOTENDED; /* Indicate in middle of data */
5518 if (!(address = parse_extract_address(smtp_cmd_data, &errmess,
5519 &start, &end, &recipient_domain, FALSE)))
5521 smtp_printf("501 %s\r\n", FALSE, errmess);
5525 if (!recipient_domain)
5526 if (!(recipient_domain = qualify_recipient(&address, smtp_cmd_data,
5530 if ((rc = acl_check(ACL_WHERE_VRFY, address, acl_smtp_vrfy,
5531 &user_msg, &log_msg)) != OK)
5532 done = smtp_handle_acl_fail(ACL_WHERE_VRFY, rc, user_msg, log_msg);
5536 address_item * addr = deliver_make_addr(address, FALSE);
5538 switch(verify_address(addr, NULL, vopt_is_recipient | vopt_qualify, -1,
5539 -1, -1, NULL, NULL, NULL))
5542 s = string_sprintf("250 <%s> is deliverable", address);
5546 s = (addr->user_message != NULL)?
5547 string_sprintf("451 <%s> %s", address, addr->user_message) :
5548 string_sprintf("451 Cannot resolve <%s> at this time", address);
5552 s = (addr->user_message != NULL)?
5553 string_sprintf("550 <%s> %s", address, addr->user_message) :
5554 string_sprintf("550 <%s> is not deliverable", address);
5555 log_write(0, LOG_MAIN, "VRFY failed for %s %s",
5556 smtp_cmd_argument, host_and_ident(TRUE));
5560 smtp_printf("%s\r\n", FALSE, s);
5568 rc = acl_check(ACL_WHERE_EXPN, NULL, acl_smtp_expn, &user_msg, &log_msg);
5570 done = smtp_handle_acl_fail(ACL_WHERE_EXPN, rc, user_msg, log_msg);
5573 BOOL save_log_testing_mode = f.log_testing_mode;
5574 f.address_test_mode = f.log_testing_mode = TRUE;
5575 (void) verify_address(deliver_make_addr(smtp_cmd_data, FALSE),
5576 smtp_out, vopt_is_recipient | vopt_qualify | vopt_expn, -1, -1, -1,
5578 f.address_test_mode = FALSE;
5579 f.log_testing_mode = save_log_testing_mode; /* true for -bh */
5588 if (!fl.tls_advertised)
5590 done = synprot_error(L_smtp_protocol_error, 503, NULL,
5591 US"STARTTLS command used when not advertised");
5595 /* Apply an ACL check if one is defined */
5597 if ( acl_smtp_starttls
5598 && (rc = acl_check(ACL_WHERE_STARTTLS, NULL, acl_smtp_starttls,
5599 &user_msg, &log_msg)) != OK
5602 done = smtp_handle_acl_fail(ACL_WHERE_STARTTLS, rc, user_msg, log_msg);
5606 /* RFC 2487 is not clear on when this command may be sent, though it
5607 does state that all information previously obtained from the client
5608 must be discarded if a TLS session is started. It seems reasonable to
5609 do an implied RSET when STARTTLS is received. */
5611 incomplete_transaction_log(US"STARTTLS");
5612 cancel_cutthrough_connection(TRUE, US"STARTTLS received");
5613 reset_point = smtp_reset(reset_point);
5615 cmd_list[CMD_LIST_STARTTLS].is_mail_cmd = FALSE;
5617 /* There's an attack where more data is read in past the STARTTLS command
5618 before TLS is negotiated, then assumed to be part of the secure session
5619 when used afterwards; we use segregated input buffers, so are not
5620 vulnerable, but we want to note when it happens and, for sheer paranoia,
5621 ensure that the buffer is "wiped".
5622 Pipelining sync checks will normally have protected us too, unless disabled
5623 by configuration. */
5628 debug_printf("Non-empty input buffer after STARTTLS; naive attack?\n");
5629 if (tls_in.active.sock < 0)
5630 smtp_inend = smtp_inptr = smtp_inbuffer;
5631 /* and if TLS is already active, tls_server_start() should fail */
5634 /* There is nothing we value in the input buffer and if TLS is successfully
5635 negotiated, we won't use this buffer again; if TLS fails, we'll just read
5636 fresh content into it. The buffer contains arbitrary content from an
5637 untrusted remote source; eg: NOOP <shellcode>\r\nSTARTTLS\r\n
5638 It seems safest to just wipe away the content rather than leave it as a
5639 target to jump to. */
5641 memset(smtp_inbuffer, 0, IN_BUFFER_SIZE);
5643 /* Attempt to start up a TLS session, and if successful, discard all
5644 knowledge that was obtained previously. At least, that's what the RFC says,
5645 and that's what happens by default. However, in order to work round YAEB,
5646 there is an option to remember the esmtp state. Sigh.
5648 We must allow for an extra EHLO command and an extra AUTH command after
5649 STARTTLS that don't add to the nonmail command count. */
5652 if ((rc = tls_server_start(&s)) == OK)
5654 if (!tls_remember_esmtp)
5655 fl.helo_seen = fl.esmtp = fl.auth_advertised = f.smtp_in_pipelining_advertised = FALSE;
5656 cmd_list[CMD_LIST_EHLO].is_mail_cmd = TRUE;
5657 cmd_list[CMD_LIST_AUTH].is_mail_cmd = TRUE;
5658 cmd_list[CMD_LIST_TLS_AUTH].is_mail_cmd = TRUE;
5659 if (sender_helo_name)
5661 sender_helo_name = NULL;
5662 host_build_sender_fullhost(); /* Rebuild */
5663 set_process_info("handling incoming TLS connection from %s",
5664 host_and_ident(FALSE));
5667 (sender_host_address ? protocols : protocols_local)
5669 ? pextend + (sender_host_authenticated ? pauthed : 0)
5671 + (tls_in.active.sock >= 0 ? pcrpted : 0)
5674 sender_host_auth_pubname = sender_host_authenticated = NULL;
5675 authenticated_id = NULL;
5676 sync_cmd_limit = NON_SYNC_CMD_NON_PIPELINING;
5677 DEBUG(D_tls) debug_printf("TLS active\n");
5678 break; /* Successful STARTTLS */
5681 (void) smtp_log_tls_fail(s);
5683 /* Some local configuration problem was discovered before actually trying
5684 to do a TLS handshake; give a temporary error. */
5688 smtp_printf("454 TLS currently unavailable\r\n", FALSE);
5692 /* Hard failure. Reject everything except QUIT or closed connection. One
5693 cause for failure is a nested STARTTLS, in which case tls_in.active remains
5694 set, but we must still reject all incoming commands. Another is a handshake
5695 failure - and there may some encrypted data still in the pipe to us, which we
5696 see as garbage commands. */
5698 DEBUG(D_tls) debug_printf("TLS failed to start\n");
5699 while (done <= 0) switch(smtp_read_command(FALSE, GETC_BUFFER_UNLIMITED))
5702 log_write(L_smtp_connection, LOG_MAIN, "%s closed by EOF",
5703 smtp_get_connection_info());
5704 smtp_notquit_exit(US"tls-failed", NULL, NULL);
5708 /* It is perhaps arguable as to which exit ACL should be called here,
5709 but as it is probably a situation that almost never arises, it
5710 probably doesn't matter. We choose to call the real QUIT ACL, which in
5711 some sense is perhaps "right". */
5714 f.smtp_in_quit = TRUE;
5717 && ((rc = acl_check(ACL_WHERE_QUIT, NULL, acl_smtp_quit, &user_msg,
5718 &log_msg)) == ERROR))
5719 log_write(0, LOG_MAIN|LOG_PANIC, "ACL for QUIT returned ERROR: %s",
5722 smtp_respond(US"221", 3, TRUE, user_msg);
5724 smtp_printf("221 %s closing connection\r\n", FALSE, smtp_active_hostname);
5725 log_write(L_smtp_connection, LOG_MAIN, "%s closed by QUIT",
5726 smtp_get_connection_info());
5731 smtp_printf("554 Security failure\r\n", FALSE);
5734 tls_close(NULL, TLS_SHUTDOWN_NOWAIT);
5739 /* The ACL for QUIT is provided for gathering statistical information or
5740 similar; it does not affect the response code, but it can supply a custom
5744 smtp_quit_handler(&user_msg, &log_msg);
5750 smtp_rset_handler();
5751 cancel_cutthrough_connection(TRUE, US"RSET received");
5752 reset_point = smtp_reset(reset_point);
5759 smtp_printf("250 OK\r\n", FALSE);
5763 /* Show ETRN/EXPN/VRFY if there's an ACL for checking hosts; if actually
5764 used, a check will be done for permitted hosts. Show STARTTLS only if not
5765 already in a TLS session and if it would be advertised in the EHLO
5770 smtp_printf("214-Commands supported:\r\n", TRUE);
5774 Ustrcat(buffer, US" AUTH");
5776 if (tls_in.active.sock < 0 &&
5777 verify_check_host(&tls_advertise_hosts) != FAIL)
5778 Ustrcat(buffer, US" STARTTLS");
5780 Ustrcat(buffer, US" HELO EHLO MAIL RCPT DATA BDAT");
5781 Ustrcat(buffer, US" NOOP QUIT RSET HELP");
5782 if (acl_smtp_etrn) Ustrcat(buffer, US" ETRN");
5783 if (acl_smtp_expn) Ustrcat(buffer, US" EXPN");
5784 if (acl_smtp_vrfy) Ustrcat(buffer, US" VRFY");
5785 smtp_printf("214%s\r\n", FALSE, buffer);
5791 incomplete_transaction_log(US"connection lost");
5792 smtp_notquit_exit(US"connection-lost", US"421",
5793 US"%s lost input connection", smtp_active_hostname);
5795 /* Don't log by default unless in the middle of a message, as some mailers
5796 just drop the call rather than sending QUIT, and it clutters up the logs.
5799 if (sender_address || recipients_count > 0)
5800 log_write(L_lost_incoming_connection, LOG_MAIN,
5801 "unexpected %s while reading SMTP command from %s%s%s D=%s",
5802 f.sender_host_unknown ? "EOF" : "disconnection",
5803 f.tcp_in_fastopen_logged
5806 ? f.tcp_in_fastopen_data ? US"TFO* " : US"TFO "
5808 host_and_ident(FALSE), smtp_read_error,
5809 string_timesince(&smtp_connection_start)
5813 log_write(L_smtp_connection, LOG_MAIN, "%s %slost%s D=%s",
5814 smtp_get_connection_info(),
5815 f.tcp_in_fastopen && !f.tcp_in_fastopen_logged ? US"TFO " : US"",
5817 string_timesince(&smtp_connection_start)
5828 done = synprot_error(L_smtp_protocol_error, 503, NULL,
5829 US"ETRN is not permitted inside a transaction");
5833 log_write(L_etrn, LOG_MAIN, "ETRN %s received from %s", smtp_cmd_argument,
5834 host_and_ident(FALSE));
5836 if ((rc = acl_check(ACL_WHERE_ETRN, NULL, acl_smtp_etrn,
5837 &user_msg, &log_msg)) != OK)
5839 done = smtp_handle_acl_fail(ACL_WHERE_ETRN, rc, user_msg, log_msg);
5843 /* Compute the serialization key for this command. */
5845 etrn_serialize_key = string_sprintf("etrn-%s\n", smtp_cmd_data);
5847 /* If a command has been specified for running as a result of ETRN, we
5848 permit any argument to ETRN. If not, only the # standard form is permitted,
5849 since that is strictly the only kind of ETRN that can be implemented
5850 according to the RFC. */
5852 if (smtp_etrn_command)
5856 etrn_command = smtp_etrn_command;
5857 deliver_domain = smtp_cmd_data;
5858 rc = transport_set_up_command(&argv, smtp_etrn_command, TRUE, 0, NULL,
5859 FALSE, US"ETRN processing", &error);
5860 deliver_domain = NULL;
5863 log_write(0, LOG_MAIN|LOG_PANIC, "failed to set up ETRN command: %s",
5865 smtp_printf("458 Internal failure\r\n", FALSE);
5870 /* Else set up to call Exim with the -R option. */
5874 if (*smtp_cmd_data++ != '#')
5876 done = synprot_error(L_smtp_syntax_error, 501, NULL,
5877 US"argument must begin with #");
5880 etrn_command = US"exim -R";
5881 argv = CUSS child_exec_exim(CEE_RETURN_ARGV, TRUE, NULL, TRUE,
5882 *queue_name ? 4 : 2,
5883 US"-R", smtp_cmd_data,
5884 US"-MCG", queue_name);
5887 /* If we are host-testing, don't actually do anything. */
5893 debug_printf("ETRN command is: %s\n", etrn_command);
5894 debug_printf("ETRN command execution skipped\n");
5896 if (user_msg == NULL) smtp_printf("250 OK\r\n", FALSE);
5897 else smtp_user_msg(US"250", user_msg);
5902 /* If ETRN queue runs are to be serialized, check the database to
5903 ensure one isn't already running. */
5905 if (smtp_etrn_serialize && !enq_start(etrn_serialize_key, 1))
5907 smtp_printf("458 Already processing %s\r\n", FALSE, smtp_cmd_data);
5911 /* Fork a child process and run the command. We don't want to have to
5912 wait for the process at any point, so set SIGCHLD to SIG_IGN before
5913 forking. It should be set that way anyway for external incoming SMTP,
5914 but we save and restore to be tidy. If serialization is required, we
5915 actually run the command in yet another process, so we can wait for it
5916 to complete and then remove the serialization lock. */
5918 oldsignal = signal(SIGCHLD, SIG_IGN);
5920 if ((pid = exim_fork(US"etrn-command")) == 0)
5922 smtp_input = FALSE; /* This process is not associated with the */
5923 (void)fclose(smtp_in); /* SMTP call any more. */
5924 (void)fclose(smtp_out);
5926 signal(SIGCHLD, SIG_DFL); /* Want to catch child */
5928 /* If not serializing, do the exec right away. Otherwise, fork down
5929 into another process. */
5931 if ( !smtp_etrn_serialize
5932 || (pid = exim_fork(US"etrn-serialised-command")) == 0)
5934 DEBUG(D_exec) debug_print_argv(argv);
5935 exim_nullstd(); /* Ensure std{in,out,err} exist */
5936 /* argv[0] should be untainted, from child_exec_exim() */
5937 execv(CS argv[0], (char *const *)argv);
5938 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "exec of \"%s\" (ETRN) failed: %s",
5939 etrn_command, strerror(errno));
5940 _exit(EXIT_FAILURE); /* paranoia */
5943 /* Obey this if smtp_serialize and the 2nd fork yielded non-zero. That
5944 is, we are in the first subprocess, after forking again. All we can do
5945 for a failing fork is to log it. Otherwise, wait for the 2nd process to
5946 complete, before removing the serialization. */
5949 log_write(0, LOG_MAIN|LOG_PANIC, "2nd fork for serialized ETRN "
5950 "failed: %s", strerror(errno));
5954 DEBUG(D_any) debug_printf("waiting for serialized ETRN process %d\n",
5956 (void)wait(&status);
5957 DEBUG(D_any) debug_printf("serialized ETRN process %d ended\n",
5961 enq_end(etrn_serialize_key);
5962 exim_underbar_exit(EXIT_SUCCESS);
5965 /* Back in the top level SMTP process. Check that we started a subprocess
5966 and restore the signal state. */
5970 log_write(0, LOG_MAIN|LOG_PANIC, "fork of process for ETRN failed: %s",
5972 smtp_printf("458 Unable to fork process\r\n", FALSE);
5973 if (smtp_etrn_serialize) enq_end(etrn_serialize_key);
5977 smtp_printf("250 OK\r\n", FALSE);
5979 smtp_user_msg(US"250", user_msg);
5981 signal(SIGCHLD, oldsignal);
5986 done = synprot_error(L_smtp_syntax_error, 501, NULL,
5987 US"unexpected argument data");
5991 /* This currently happens only for NULLs, but could be extended. */
5994 done = synprot_error(L_smtp_syntax_error, 0, NULL, /* Just logs */
5995 US"NUL character(s) present (shown as '?')");
5996 smtp_printf("501 NUL characters are not allowed in SMTP commands\r\n",
6003 if (smtp_inend >= smtp_inbuffer + IN_BUFFER_SIZE)
6004 smtp_inend = smtp_inbuffer + IN_BUFFER_SIZE - 1;
6005 c = smtp_inend - smtp_inptr;
6006 if (c > 150) c = 150; /* limit logged amount */
6008 incomplete_transaction_log(US"sync failure");
6009 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP protocol synchronization error "
6010 "(next input sent too soon: pipelining was%s advertised): "
6011 "rejected \"%s\" %s next input=\"%s\"",
6012 f.smtp_in_pipelining_advertised ? "" : " not",
6013 smtp_cmd_buffer, host_and_ident(TRUE),
6014 string_printing(smtp_inptr));
6015 smtp_notquit_exit(US"synchronization-error", US"554",
6016 US"SMTP synchronization error");
6017 done = 1; /* Pretend eof - drops connection */
6021 case TOO_MANY_NONMAIL_CMD:
6022 s = smtp_cmd_buffer;
6023 while (*s != 0 && !isspace(*s)) s++;
6024 incomplete_transaction_log(US"too many non-mail commands");
6025 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
6026 "nonmail commands (last was \"%.*s\")", host_and_ident(FALSE),
6027 (int)(s - smtp_cmd_buffer), smtp_cmd_buffer);
6028 smtp_notquit_exit(US"bad-commands", US"554", US"Too many nonmail commands");
6029 done = 1; /* Pretend eof - drops connection */
6032 #ifdef SUPPORT_PROXY
6033 case PROXY_FAIL_IGNORE_CMD:
6034 smtp_printf("503 Command refused, required Proxy negotiation failed\r\n", FALSE);
6039 if (unknown_command_count++ >= smtp_max_unknown_commands)
6041 log_write(L_smtp_syntax_error, LOG_MAIN,
6042 "SMTP syntax error in \"%s\" %s %s",
6043 string_printing(smtp_cmd_buffer), host_and_ident(TRUE),
6044 US"unrecognized command");
6045 incomplete_transaction_log(US"unrecognized command");
6046 smtp_notquit_exit(US"bad-commands", US"500",
6047 US"Too many unrecognized commands");
6049 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
6050 "unrecognized commands (last was \"%s\")", host_and_ident(FALSE),
6051 string_printing(smtp_cmd_buffer));
6054 done = synprot_error(L_smtp_syntax_error, 500, NULL,
6055 US"unrecognized command");
6059 /* This label is used by goto's inside loops that want to break out to
6060 the end of the command-processing loop. */
6063 last_was_rej_mail = was_rej_mail; /* Remember some last commands for */
6064 last_was_rcpt = was_rcpt; /* protocol error handling */
6067 return done - 2; /* Convert yield values */
6073 authres_smtpauth(gstring * g)
6075 if (!sender_host_authenticated)
6078 g = string_append(g, 2, US";\n\tauth=pass (", sender_host_auth_pubname);
6080 if (Ustrcmp(sender_host_auth_pubname, "tls") == 0)
6081 g = authenticated_id
6082 ? string_append(g, 2, US") x509.auth=", authenticated_id)
6083 : string_cat(g, US") reason=x509.auth");
6085 g = authenticated_id
6086 ? string_append(g, 2, US") smtp.auth=", authenticated_id)
6087 : string_cat(g, US", no id saved)");
6089 if (authenticated_sender)
6090 g = string_append(g, 2, US" smtp.mailfrom=", authenticated_sender);
6098 /* End of smtp_in.c */