1 /*************************************************
2 * Exim - an Internet mail transport agent *
3 *************************************************/
5 /* Copyright (c) University of Cambridge 1995 - 2014 */
6 /* See the file NOTICE for conditions of use and distribution. */
8 /* Functions for handling an incoming SMTP call. */
14 /* Initialize for TCP wrappers if so configured. It appears that the macro
15 HAVE_IPV6 is used in some versions of the tcpd.h header, so we unset it before
16 including that header, and restore its value afterwards. */
18 #ifdef USE_TCP_WRAPPERS
21 #define EXIM_HAVE_IPV6
27 #define HAVE_IPV6 TRUE
30 int allow_severity = LOG_INFO;
31 int deny_severity = LOG_NOTICE;
32 uschar *tcp_wrappers_name;
36 /* Size of buffer for reading SMTP commands. We used to use 512, as defined
37 by RFC 821. However, RFC 1869 specifies that this must be increased for SMTP
38 commands that accept arguments, and this in particular applies to AUTH, where
39 the data can be quite long. More recently this value was 2048 in Exim;
40 however, RFC 4954 (circa 2007) recommends 12288 bytes to handle AUTH. Clients
41 such as Thunderbird will send an AUTH with an initial-response for GSSAPI.
42 The maximum size of a Kerberos ticket under Windows 2003 is 12000 bytes, and
43 we need room to handle large base64-encoded AUTHs for GSSAPI.
46 #define smtp_cmd_buffer_size 16384
48 /* Size of buffer for reading SMTP incoming packets */
50 #define in_buffer_size 8192
52 /* Structure for SMTP command list */
59 short int is_mail_cmd;
62 /* Codes for identifying commands. We order them so that those that come first
63 are those for which synchronization is always required. Checking this can help
67 /* These commands are required to be synchronized, i.e. to be the last in a
68 block of commands when pipelining. */
70 HELO_CMD, EHLO_CMD, DATA_CMD, /* These are listed in the pipelining */
71 VRFY_CMD, EXPN_CMD, NOOP_CMD, /* RFC as requiring synchronization */
72 ETRN_CMD, /* This by analogy with TURN from the RFC */
73 STARTTLS_CMD, /* Required by the STARTTLS RFC */
75 /* This is a dummy to identify the non-sync commands when pipelining */
77 NON_SYNC_CMD_PIPELINING,
79 /* These commands need not be synchronized when pipelining */
81 MAIL_CMD, RCPT_CMD, RSET_CMD,
83 /* This is a dummy to identify the non-sync commands when not pipelining */
85 NON_SYNC_CMD_NON_PIPELINING,
87 /* I have been unable to find a statement about the use of pipelining
88 with AUTH, so to be on the safe side it is here, though I kind of feel
89 it should be up there with the synchronized commands. */
93 /* I'm not sure about these, but I don't think they matter. */
97 #ifdef EXPERIMENTAL_PROXY
98 PROXY_FAIL_IGNORE_CMD,
101 /* These are specials that don't correspond to actual commands */
103 EOF_CMD, OTHER_CMD, BADARG_CMD, BADCHAR_CMD, BADSYN_CMD,
104 TOO_MANY_NONMAIL_CMD };
107 /* This is a convenience macro for adding the identity of an SMTP command
108 to the circular buffer that holds a list of the last n received. */
111 smtp_connection_had[smtp_ch_index++] = n; \
112 if (smtp_ch_index >= SMTP_HBUFF_SIZE) smtp_ch_index = 0
115 /*************************************************
116 * Local static variables *
117 *************************************************/
119 static auth_instance *authenticated_by;
120 static BOOL auth_advertised;
122 static BOOL tls_advertised;
124 static BOOL dsn_advertised;
126 static BOOL helo_required = FALSE;
127 static BOOL helo_verify = FALSE;
128 static BOOL helo_seen;
129 static BOOL helo_accept_junk;
130 static BOOL count_nonmail;
131 static BOOL pipelining_advertised;
132 static BOOL rcpt_smtp_response_same;
133 static BOOL rcpt_in_progress;
134 static int nonmail_command_count;
135 static BOOL smtp_exit_function_called = 0;
136 #ifdef EXPERIMENTAL_INTERNATIONAL
137 static BOOL smtputf8_advertised;
139 static int synprot_error_count;
140 static int unknown_command_count;
141 static int sync_cmd_limit;
142 static int smtp_write_error = 0;
144 static uschar *rcpt_smtp_response;
145 static uschar *smtp_data_buffer;
146 static uschar *smtp_cmd_data;
148 /* We need to know the position of RSET, HELO, EHLO, AUTH, and STARTTLS. Their
149 final fields of all except AUTH are forced TRUE at the start of a new message
150 setup, to allow one of each between messages that is not counted as a nonmail
151 command. (In fact, only one of HELO/EHLO is not counted.) Also, we have to
152 allow a new EHLO after starting up TLS.
154 AUTH is "falsely" labelled as a mail command initially, so that it doesn't get
155 counted. However, the flag is changed when AUTH is received, so that multiple
156 failing AUTHs will eventually hit the limit. After a successful AUTH, another
157 AUTH is already forbidden. After a TLS session is started, AUTH's flag is again
158 forced TRUE, to allow for the re-authentication that can happen at that point.
160 QUIT is also "falsely" labelled as a mail command so that it doesn't up the
161 count of non-mail commands and possibly provoke an error. */
163 static smtp_cmd_list cmd_list[] = {
164 /* name len cmd has_arg is_mail_cmd */
166 { "rset", sizeof("rset")-1, RSET_CMD, FALSE, FALSE }, /* First */
167 { "helo", sizeof("helo")-1, HELO_CMD, TRUE, FALSE },
168 { "ehlo", sizeof("ehlo")-1, EHLO_CMD, TRUE, FALSE },
169 { "auth", sizeof("auth")-1, AUTH_CMD, TRUE, TRUE },
171 { "starttls", sizeof("starttls")-1, STARTTLS_CMD, FALSE, FALSE },
174 /* If you change anything above here, also fix the definitions below. */
176 { "mail from:", sizeof("mail from:")-1, MAIL_CMD, TRUE, TRUE },
177 { "rcpt to:", sizeof("rcpt to:")-1, RCPT_CMD, TRUE, TRUE },
178 { "data", sizeof("data")-1, DATA_CMD, FALSE, TRUE },
179 { "quit", sizeof("quit")-1, QUIT_CMD, FALSE, TRUE },
180 { "noop", sizeof("noop")-1, NOOP_CMD, TRUE, FALSE },
181 { "etrn", sizeof("etrn")-1, ETRN_CMD, TRUE, FALSE },
182 { "vrfy", sizeof("vrfy")-1, VRFY_CMD, TRUE, FALSE },
183 { "expn", sizeof("expn")-1, EXPN_CMD, TRUE, FALSE },
184 { "help", sizeof("help")-1, HELP_CMD, TRUE, FALSE }
187 static smtp_cmd_list *cmd_list_end =
188 cmd_list + sizeof(cmd_list)/sizeof(smtp_cmd_list);
190 #define CMD_LIST_RSET 0
191 #define CMD_LIST_HELO 1
192 #define CMD_LIST_EHLO 2
193 #define CMD_LIST_AUTH 3
194 #define CMD_LIST_STARTTLS 4
196 /* This list of names is used for performing the smtp_no_mail logging action.
197 It must be kept in step with the SCH_xxx enumerations. */
199 static uschar *smtp_names[] =
201 US"NONE", US"AUTH", US"DATA", US"EHLO", US"ETRN", US"EXPN", US"HELO",
202 US"HELP", US"MAIL", US"NOOP", US"QUIT", US"RCPT", US"RSET", US"STARTTLS",
205 static uschar *protocols_local[] = {
206 US"local-smtp", /* HELO */
207 US"local-smtps", /* The rare case EHLO->STARTTLS->HELO */
208 US"local-esmtp", /* EHLO */
209 US"local-esmtps", /* EHLO->STARTTLS->EHLO */
210 US"local-esmtpa", /* EHLO->AUTH */
211 US"local-esmtpsa" /* EHLO->STARTTLS->EHLO->AUTH */
213 static uschar *protocols[] = {
215 US"smtps", /* The rare case EHLO->STARTTLS->HELO */
216 US"esmtp", /* EHLO */
217 US"esmtps", /* EHLO->STARTTLS->EHLO */
218 US"esmtpa", /* EHLO->AUTH */
219 US"esmtpsa" /* EHLO->STARTTLS->EHLO->AUTH */
224 #define pcrpted 1 /* added to pextend or pnormal */
225 #define pauthed 2 /* added to pextend */
227 /* Sanity check and validate optional args to MAIL FROM: envelope */
229 ENV_MAIL_OPT_SIZE, ENV_MAIL_OPT_BODY, ENV_MAIL_OPT_AUTH,
233 ENV_MAIL_OPT_RET, ENV_MAIL_OPT_ENVID,
234 #ifdef EXPERIMENTAL_INTERNATIONAL
240 uschar * name; /* option requested during MAIL cmd */
241 int value; /* enum type */
242 BOOL need_value; /* TRUE requires value (name=value pair format)
243 FALSE is a singleton */
245 static env_mail_type_t env_mail_type_list[] = {
246 { US"SIZE", ENV_MAIL_OPT_SIZE, TRUE },
247 { US"BODY", ENV_MAIL_OPT_BODY, TRUE },
248 { US"AUTH", ENV_MAIL_OPT_AUTH, TRUE },
250 { US"PRDR", ENV_MAIL_OPT_PRDR, FALSE },
252 { US"RET", ENV_MAIL_OPT_RET, TRUE },
253 { US"ENVID", ENV_MAIL_OPT_ENVID, TRUE },
254 #ifdef EXPERIMENTAL_INTERNATIONAL
255 { US"SMTPUTF8",ENV_MAIL_OPT_UTF8, FALSE }, /* rfc6531 */
257 { US"NULL", ENV_MAIL_OPT_NULL, FALSE }
260 /* When reading SMTP from a remote host, we have to use our own versions of the
261 C input-reading functions, in order to be able to flush the SMTP output only
262 when about to read more data from the socket. This is the only way to get
263 optimal performance when the client is using pipelining. Flushing for every
264 command causes a separate packet and reply packet each time; saving all the
265 responses up (when pipelining) combines them into one packet and one response.
267 For simplicity, these functions are used for *all* SMTP input, not only when
268 receiving over a socket. However, after setting up a secure socket (SSL), input
269 is read via the OpenSSL library, and another set of functions is used instead
272 These functions are set in the receive_getc etc. variables and called with the
273 same interface as the C functions. However, since there can only ever be
274 one incoming SMTP call, we just use a single buffer and flags. There is no need
275 to implement a complicated private FILE-like structure.*/
277 static uschar *smtp_inbuffer;
278 static uschar *smtp_inptr;
279 static uschar *smtp_inend;
280 static int smtp_had_eof;
281 static int smtp_had_error;
284 /*************************************************
285 * SMTP version of getc() *
286 *************************************************/
288 /* This gets the next byte from the SMTP input buffer. If the buffer is empty,
289 it flushes the output, and refills the buffer, with a timeout. The signal
290 handler is set appropriately by the calling function. This function is not used
291 after a connection has negotated itself into an TLS/SSL state.
294 Returns: the next character or EOF
300 if (smtp_inptr >= smtp_inend)
304 if (smtp_receive_timeout > 0) alarm(smtp_receive_timeout);
305 rc = read(fileno(smtp_in), smtp_inbuffer, in_buffer_size);
310 /* Must put the error text in fixed store, because this might be during
311 header reading, where it releases unused store above the header. */
314 smtp_had_error = save_errno;
315 smtp_read_error = string_copy_malloc(
316 string_sprintf(" (error: %s)", strerror(save_errno)));
318 else smtp_had_eof = 1;
322 dkim_exim_verify_feed(smtp_inbuffer, rc);
324 smtp_inend = smtp_inbuffer + rc;
325 smtp_inptr = smtp_inbuffer;
327 return *smtp_inptr++;
332 /*************************************************
333 * SMTP version of ungetc() *
334 *************************************************/
336 /* Puts a character back in the input buffer. Only ever
342 Returns: the character
348 *(--smtp_inptr) = ch;
355 /*************************************************
356 * SMTP version of feof() *
357 *************************************************/
359 /* Tests for a previous EOF
362 Returns: non-zero if the eof flag is set
374 /*************************************************
375 * SMTP version of ferror() *
376 *************************************************/
378 /* Tests for a previous read error, and returns with errno
379 restored to what it was when the error was detected.
382 Returns: non-zero if the error flag is set
388 errno = smtp_had_error;
389 return smtp_had_error;
394 /*************************************************
395 * Test for characters in the SMTP buffer *
396 *************************************************/
398 /* Used at the end of a message
407 return smtp_inptr < smtp_inend;
412 /*************************************************
413 * Write formatted string to SMTP channel *
414 *************************************************/
416 /* This is a separate function so that we don't have to repeat everything for
417 TLS support or debugging. It is global so that the daemon and the
418 authentication functions can use it. It does not return any error indication,
419 because major problems such as dropped connections won't show up till an output
420 flush for non-TLS connections. The smtp_fflush() function is available for
421 checking that: for convenience, TLS output errors are remembered here so that
422 they are also picked up later by smtp_fflush().
426 ... optional arguments
432 smtp_printf(const char *format, ...)
436 va_start(ap, format);
437 smtp_vprintf(format, ap);
441 /* This is split off so that verify.c:respond_printf() can, in effect, call
442 smtp_printf(), bearing in mind that in C a vararg function can't directly
443 call another vararg function, only a function which accepts a va_list. */
446 smtp_vprintf(const char *format, va_list ap)
450 yield = string_vformat(big_buffer, big_buffer_size, format, ap);
454 void *reset_point = store_get(0);
455 uschar *msg_copy, *cr, *end;
456 msg_copy = string_copy(big_buffer);
457 end = msg_copy + Ustrlen(msg_copy);
458 while ((cr = Ustrchr(msg_copy, '\r')) != NULL) /* lose CRs */
459 memmove(cr, cr + 1, (end--) - cr);
460 debug_printf("SMTP>> %s", msg_copy);
461 store_reset(reset_point);
466 log_write(0, LOG_MAIN|LOG_PANIC, "string too large in smtp_printf()");
467 smtp_closedown(US"Unexpected error");
468 exim_exit(EXIT_FAILURE);
471 /* If this is the first output for a (non-batch) RCPT command, see if all RCPTs
472 have had the same. Note: this code is also present in smtp_respond(). It would
473 be tidier to have it only in one place, but when it was added, it was easier to
474 do it that way, so as not to have to mess with the code for the RCPT command,
475 which sometimes uses smtp_printf() and sometimes smtp_respond(). */
477 if (rcpt_in_progress)
479 if (rcpt_smtp_response == NULL)
480 rcpt_smtp_response = string_copy(big_buffer);
481 else if (rcpt_smtp_response_same &&
482 Ustrcmp(rcpt_smtp_response, big_buffer) != 0)
483 rcpt_smtp_response_same = FALSE;
484 rcpt_in_progress = FALSE;
487 /* Now write the string */
490 if (tls_in.active >= 0)
492 if (tls_write(TRUE, big_buffer, Ustrlen(big_buffer)) < 0)
493 smtp_write_error = -1;
498 if (fprintf(smtp_out, "%s", big_buffer) < 0) smtp_write_error = -1;
503 /*************************************************
504 * Flush SMTP out and check for error *
505 *************************************************/
507 /* This function isn't currently used within Exim (it detects errors when it
508 tries to read the next SMTP input), but is available for use in local_scan().
509 For non-TLS connections, it flushes the output and checks for errors. For
510 TLS-connections, it checks for a previously-detected TLS write error.
513 Returns: 0 for no error; -1 after an error
519 if (tls_in.active < 0 && fflush(smtp_out) != 0) smtp_write_error = -1;
520 return smtp_write_error;
525 /*************************************************
526 * SMTP command read timeout *
527 *************************************************/
529 /* Signal handler for timing out incoming SMTP commands. This attempts to
532 Argument: signal number (SIGALRM)
537 command_timeout_handler(int sig)
539 sig = sig; /* Keep picky compilers happy */
540 log_write(L_lost_incoming_connection,
541 LOG_MAIN, "SMTP command timeout on%s connection from %s",
542 (tls_in.active >= 0)? " TLS" : "",
543 host_and_ident(FALSE));
544 if (smtp_batched_input)
545 moan_smtp_batch(NULL, "421 SMTP command timeout"); /* Does not return */
546 smtp_notquit_exit(US"command-timeout", US"421",
547 US"%s: SMTP command timeout - closing connection", smtp_active_hostname);
548 exim_exit(EXIT_FAILURE);
553 /*************************************************
555 *************************************************/
557 /* Signal handler for handling SIGTERM. Again, try to finish tidily.
559 Argument: signal number (SIGTERM)
564 command_sigterm_handler(int sig)
566 sig = sig; /* Keep picky compilers happy */
567 log_write(0, LOG_MAIN, "%s closed after SIGTERM", smtp_get_connection_info());
568 if (smtp_batched_input)
569 moan_smtp_batch(NULL, "421 SIGTERM received"); /* Does not return */
570 smtp_notquit_exit(US"signal-exit", US"421",
571 US"%s: Service not available - closing connection", smtp_active_hostname);
572 exim_exit(EXIT_FAILURE);
578 #ifdef EXPERIMENTAL_PROXY
579 /*************************************************
580 * Restore socket timeout to previous value *
581 *************************************************/
582 /* If the previous value was successfully retrieved, restore
583 it before returning control to the non-proxy routines
585 Arguments: fd - File descriptor for input
586 get_ok - Successfully retrieved previous values
587 tvtmp - Time struct with previous values
588 vslen - Length of time struct
592 restore_socket_timeout(int fd, int get_ok, struct timeval tvtmp, socklen_t vslen)
595 setsockopt(fd, SOL_SOCKET, SO_RCVTIMEO, (char *)&tvtmp, vslen);
598 /*************************************************
599 * Check if host is required proxy host *
600 *************************************************/
601 /* The function determines if inbound host will be a regular smtp host
602 or if it is configured that it must use Proxy Protocol.
609 check_proxy_protocol_host()
612 /* Cannot configure local connection as a proxy inbound */
613 if (sender_host_address == NULL) return proxy_session;
615 rc = verify_check_this_host(&proxy_required_hosts, NULL, NULL,
616 sender_host_address, NULL);
620 debug_printf("Detected proxy protocol configured host\n");
621 proxy_session = TRUE;
623 return proxy_session;
627 /*************************************************
628 * Setup host for proxy protocol *
629 *************************************************/
630 /* The function configures the connection based on a header from the
631 inbound host to use Proxy Protocol. The specification is very exact
632 so exit with an error if do not find the exact required pieces. This
633 includes an incorrect number of spaces separating args.
640 setup_proxy_protocol_host()
652 struct { /* TCP/UDP over IPv4, len = 12 */
658 struct { /* TCP/UDP over IPv6, len = 36 */
659 uint8_t src_addr[16];
660 uint8_t dst_addr[16];
664 struct { /* AF_UNIX sockets, len = 216 */
665 uschar src_addr[108];
666 uschar dst_addr[108];
672 /* Temp variables used in PPv2 address:port parsing */
674 char tmpip[INET_ADDRSTRLEN];
675 struct sockaddr_in tmpaddr;
676 char tmpip6[INET6_ADDRSTRLEN];
677 struct sockaddr_in6 tmpaddr6;
681 const char v2sig[12] = "\x0D\x0A\x0D\x0A\x00\x0D\x0A\x51\x55\x49\x54\x0A";
682 uschar *iptype; /* To display debug info */
685 struct timeval tvtmp;
687 vslen = sizeof(struct timeval);
689 fd = fileno(smtp_in);
691 /* Save current socket timeout values */
692 get_ok = getsockopt(fd, SOL_SOCKET, SO_RCVTIMEO, (char *)&tvtmp,
695 /* Proxy Protocol host must send header within a short time
696 (default 3 seconds) or it's considered invalid */
697 tv.tv_sec = PROXY_NEGOTIATION_TIMEOUT_SEC;
698 tv.tv_usec = PROXY_NEGOTIATION_TIMEOUT_USEC;
699 setsockopt(fd, SOL_SOCKET, SO_RCVTIMEO, (char *)&tv,
700 sizeof(struct timeval));
704 /* The inbound host was declared to be a Proxy Protocol host, so
705 don't do a PEEK into the data, actually slurp it up. */
706 ret = recv(fd, &hdr, sizeof(hdr), 0);
708 while (ret == -1 && errno == EINTR);
712 restore_socket_timeout(fd, get_ok, tvtmp, vslen);
713 return (errno == EAGAIN) ? 0 : ERRNO_PROXYFAIL;
717 memcmp(&hdr.v2, v2sig, 12) == 0)
721 /* May 2014: haproxy combined the version and command into one byte to
722 allow two full bytes for the length field in order to proxy SSL
723 connections. SSL Proxy is not supported in this version of Exim, but
724 must still seperate values here. */
725 ver = (hdr.v2.ver_cmd & 0xf0) >> 4;
726 cmd = (hdr.v2.ver_cmd & 0x0f);
730 DEBUG(D_receive) debug_printf("Invalid Proxy Protocol version: %d\n", ver);
733 DEBUG(D_receive) debug_printf("Detected PROXYv2 header\n");
734 /* The v2 header will always be 16 bytes per the spec. */
735 size = 16 + hdr.v2.len;
738 DEBUG(D_receive) debug_printf("Truncated or too large PROXYv2 header (%d/%d)\n",
744 case 0x01: /* PROXY command */
747 case 0x11: /* TCPv4 address type */
749 tmpaddr.sin_addr.s_addr = hdr.v2.addr.ip4.src_addr;
750 inet_ntop(AF_INET, &(tmpaddr.sin_addr), (char *)&tmpip, sizeof(tmpip));
751 if (!string_is_ip_address(US tmpip,NULL))
753 DEBUG(D_receive) debug_printf("Invalid %s source IP\n", iptype);
754 return ERRNO_PROXYFAIL;
756 proxy_host_address = sender_host_address;
757 sender_host_address = string_copy(US tmpip);
758 tmpport = ntohs(hdr.v2.addr.ip4.src_port);
759 proxy_host_port = sender_host_port;
760 sender_host_port = tmpport;
761 /* Save dest ip/port */
762 tmpaddr.sin_addr.s_addr = hdr.v2.addr.ip4.dst_addr;
763 inet_ntop(AF_INET, &(tmpaddr.sin_addr), (char *)&tmpip, sizeof(tmpip));
764 if (!string_is_ip_address(US tmpip,NULL))
766 DEBUG(D_receive) debug_printf("Invalid %s dest port\n", iptype);
767 return ERRNO_PROXYFAIL;
769 proxy_target_address = string_copy(US tmpip);
770 tmpport = ntohs(hdr.v2.addr.ip4.dst_port);
771 proxy_target_port = tmpport;
773 case 0x21: /* TCPv6 address type */
775 memmove(tmpaddr6.sin6_addr.s6_addr, hdr.v2.addr.ip6.src_addr, 16);
776 inet_ntop(AF_INET6, &(tmpaddr6.sin6_addr), (char *)&tmpip6, sizeof(tmpip6));
777 if (!string_is_ip_address(US tmpip6,NULL))
779 DEBUG(D_receive) debug_printf("Invalid %s source IP\n", iptype);
780 return ERRNO_PROXYFAIL;
782 proxy_host_address = sender_host_address;
783 sender_host_address = string_copy(US tmpip6);
784 tmpport = ntohs(hdr.v2.addr.ip6.src_port);
785 proxy_host_port = sender_host_port;
786 sender_host_port = tmpport;
787 /* Save dest ip/port */
788 memmove(tmpaddr6.sin6_addr.s6_addr, hdr.v2.addr.ip6.dst_addr, 16);
789 inet_ntop(AF_INET6, &(tmpaddr6.sin6_addr), (char *)&tmpip6, sizeof(tmpip6));
790 if (!string_is_ip_address(US tmpip6,NULL))
792 DEBUG(D_receive) debug_printf("Invalid %s dest port\n", iptype);
793 return ERRNO_PROXYFAIL;
795 proxy_target_address = string_copy(US tmpip6);
796 tmpport = ntohs(hdr.v2.addr.ip6.dst_port);
797 proxy_target_port = tmpport;
801 debug_printf("Unsupported PROXYv2 connection type: 0x%02x\n",
805 /* Unsupported protocol, keep local connection address */
807 case 0x00: /* LOCAL command */
808 /* Keep local connection address for LOCAL */
812 debug_printf("Unsupported PROXYv2 command: 0x%x\n", cmd);
817 memcmp(hdr.v1.line, "PROXY", 5) == 0)
819 uschar *p = string_copy(hdr.v1.line);
820 uschar *end = memchr(p, '\r', ret - 1);
821 uschar *sp; /* Utility variables follow */
825 if (!end || end[1] != '\n')
827 DEBUG(D_receive) debug_printf("Partial or invalid PROXY header\n");
830 *end = '\0'; /* Terminate the string */
831 size = end + 2 - hdr.v1.line; /* Skip header + CRLF */
832 DEBUG(D_receive) debug_printf("Detected PROXYv1 header\n");
833 /* Step through the string looking for the required fields. Ensure
834 strict adherance to required formatting, exit for any error. */
836 if (!isspace(*(p++)))
838 DEBUG(D_receive) debug_printf("Missing space after PROXY command\n");
841 if (!Ustrncmp(p, CCS"TCP4", 4))
843 else if (!Ustrncmp(p,CCS"TCP6", 4))
845 else if (!Ustrncmp(p,CCS"UNKNOWN", 7))
847 iptype = US"Unknown";
852 DEBUG(D_receive) debug_printf("Invalid TCP type\n");
856 p += Ustrlen(iptype);
857 if (!isspace(*(p++)))
859 DEBUG(D_receive) debug_printf("Missing space after TCP4/6 command\n");
862 /* Find the end of the arg */
863 if ((sp = Ustrchr(p, ' ')) == NULL)
866 debug_printf("Did not find proxied src %s\n", iptype);
870 if(!string_is_ip_address(p,NULL))
873 debug_printf("Proxied src arg is not an %s address\n", iptype);
876 proxy_host_address = sender_host_address;
877 sender_host_address = p;
879 if ((sp = Ustrchr(p, ' ')) == NULL)
882 debug_printf("Did not find proxy dest %s\n", iptype);
886 if(!string_is_ip_address(p,NULL))
889 debug_printf("Proxy dest arg is not an %s address\n", iptype);
892 proxy_target_address = p;
894 if ((sp = Ustrchr(p, ' ')) == NULL)
896 DEBUG(D_receive) debug_printf("Did not find proxied src port\n");
900 tmp_port = strtol(CCS p,&endc,10);
901 if (*endc || tmp_port == 0)
904 debug_printf("Proxied src port '%s' not an integer\n", p);
907 proxy_host_port = sender_host_port;
908 sender_host_port = tmp_port;
910 if ((sp = Ustrchr(p, '\0')) == NULL)
912 DEBUG(D_receive) debug_printf("Did not find proxy dest port\n");
915 tmp_port = strtol(CCS p,&endc,10);
916 if (*endc || tmp_port == 0)
919 debug_printf("Proxy dest port '%s' not an integer\n", p);
922 proxy_target_port = tmp_port;
923 /* Already checked for /r /n above. Good V1 header received. */
929 DEBUG(D_receive) debug_printf("Invalid proxy protocol version negotiation\n");
934 restore_socket_timeout(fd, get_ok, tvtmp, vslen);
935 /* Don't flush any potential buffer contents. Any input should cause a
936 synchronization failure */
940 restore_socket_timeout(fd, get_ok, tvtmp, vslen);
942 debug_printf("Valid %s sender from Proxy Protocol header\n", iptype);
943 return proxy_session;
947 /*************************************************
948 * Read one command line *
949 *************************************************/
951 /* Strictly, SMTP commands coming over the net are supposed to end with CRLF.
952 There are sites that don't do this, and in any case internal SMTP probably
953 should check only for LF. Consequently, we check here for LF only. The line
954 ends up with [CR]LF removed from its end. If we get an overlong line, treat as
955 an unknown command. The command is read into the global smtp_cmd_buffer so that
956 it is available via $smtp_command.
958 The character reading routine sets up a timeout for each block actually read
959 from the input (which may contain more than one command). We set up a special
960 signal handler that closes down the session on a timeout. Control does not
964 check_sync if TRUE, check synchronization rules if global option is TRUE
966 Returns: a code identifying the command (enumerated above)
970 smtp_read_command(BOOL check_sync)
975 BOOL hadnull = FALSE;
977 os_non_restarting_signal(SIGALRM, command_timeout_handler);
979 while ((c = (receive_getc)()) != '\n' && c != EOF)
981 if (ptr >= smtp_cmd_buffer_size)
983 os_non_restarting_signal(SIGALRM, sigalrm_handler);
991 smtp_cmd_buffer[ptr++] = c;
994 receive_linecount++; /* For BSMTP errors */
995 os_non_restarting_signal(SIGALRM, sigalrm_handler);
997 /* If hit end of file, return pseudo EOF command. Whether we have a
998 part-line already read doesn't matter, since this is an error state. */
1000 if (c == EOF) return EOF_CMD;
1002 /* Remove any CR and white space at the end of the line, and terminate the
1005 while (ptr > 0 && isspace(smtp_cmd_buffer[ptr-1])) ptr--;
1006 smtp_cmd_buffer[ptr] = 0;
1008 DEBUG(D_receive) debug_printf("SMTP<< %s\n", smtp_cmd_buffer);
1010 /* NULLs are not allowed in SMTP commands */
1012 if (hadnull) return BADCHAR_CMD;
1014 /* Scan command list and return identity, having set the data pointer
1015 to the start of the actual data characters. Check for SMTP synchronization
1018 for (p = cmd_list; p < cmd_list_end; p++)
1020 #ifdef EXPERIMENTAL_PROXY
1021 /* Only allow QUIT command if Proxy Protocol parsing failed */
1022 if (proxy_session && proxy_session_failed)
1024 if (p->cmd != QUIT_CMD)
1028 if (strncmpic(smtp_cmd_buffer, US p->name, p->len) == 0 &&
1029 (smtp_cmd_buffer[p->len-1] == ':' || /* "mail from:" or "rcpt to:" */
1030 smtp_cmd_buffer[p->len] == 0 ||
1031 smtp_cmd_buffer[p->len] == ' '))
1033 if (smtp_inptr < smtp_inend && /* Outstanding input */
1034 p->cmd < sync_cmd_limit && /* Command should sync */
1035 check_sync && /* Local flag set */
1036 smtp_enforce_sync && /* Global flag set */
1037 sender_host_address != NULL && /* Not local input */
1038 !sender_host_notsocket) /* Really is a socket */
1041 /* The variables $smtp_command and $smtp_command_argument point into the
1042 unmodified input buffer. A copy of the latter is taken for actual
1043 processing, so that it can be chopped up into separate parts if necessary,
1044 for example, when processing a MAIL command options such as SIZE that can
1045 follow the sender address. */
1047 smtp_cmd_argument = smtp_cmd_buffer + p->len;
1048 while (isspace(*smtp_cmd_argument)) smtp_cmd_argument++;
1049 Ustrcpy(smtp_data_buffer, smtp_cmd_argument);
1050 smtp_cmd_data = smtp_data_buffer;
1052 /* Count non-mail commands from those hosts that are controlled in this
1053 way. The default is all hosts. We don't waste effort checking the list
1054 until we get a non-mail command, but then cache the result to save checking
1055 again. If there's a DEFER while checking the host, assume it's in the list.
1057 Note that one instance of RSET, EHLO/HELO, and STARTTLS is allowed at the
1058 start of each incoming message by fiddling with the value in the table. */
1060 if (!p->is_mail_cmd)
1062 if (count_nonmail == TRUE_UNSET) count_nonmail =
1063 verify_check_host(&smtp_accept_max_nonmail_hosts) != FAIL;
1064 if (count_nonmail && ++nonmail_command_count > smtp_accept_max_nonmail)
1065 return TOO_MANY_NONMAIL_CMD;
1068 /* If there is data for a command that does not expect it, generate the
1071 return (p->has_arg || *smtp_cmd_data == 0)? p->cmd : BADARG_CMD;
1075 #ifdef EXPERIMENTAL_PROXY
1076 /* Only allow QUIT command if Proxy Protocol parsing failed */
1077 if (proxy_session && proxy_session_failed)
1078 return PROXY_FAIL_IGNORE_CMD;
1081 /* Enforce synchronization for unknown commands */
1083 if (smtp_inptr < smtp_inend && /* Outstanding input */
1084 check_sync && /* Local flag set */
1085 smtp_enforce_sync && /* Global flag set */
1086 sender_host_address != NULL && /* Not local input */
1087 !sender_host_notsocket) /* Really is a socket */
1095 /*************************************************
1096 * Recheck synchronization *
1097 *************************************************/
1099 /* Synchronization checks can never be perfect because a packet may be on its
1100 way but not arrived when the check is done. Such checks can in any case only be
1101 done when TLS is not in use. Normally, the checks happen when commands are
1102 read: Exim ensures that there is no more input in the input buffer. In normal
1103 cases, the response to the command will be fast, and there is no further check.
1105 However, for some commands an ACL is run, and that can include delays. In those
1106 cases, it is useful to do another check on the input just before sending the
1107 response. This also applies at the start of a connection. This function does
1108 that check by means of the select() function, as long as the facility is not
1109 disabled or inappropriate. A failure of select() is ignored.
1111 When there is unwanted input, we read it so that it appears in the log of the
1115 Returns: TRUE if all is well; FALSE if there is input pending
1123 struct timeval tzero;
1125 if (!smtp_enforce_sync || sender_host_address == NULL ||
1126 sender_host_notsocket || tls_in.active >= 0)
1129 fd = fileno(smtp_in);
1134 rc = select(fd + 1, (SELECT_ARG2_TYPE *)&fds, NULL, NULL, &tzero);
1136 if (rc <= 0) return TRUE; /* Not ready to read */
1138 if (rc < 0) return TRUE; /* End of file or error */
1141 rc = smtp_inend - smtp_inptr;
1142 if (rc > 150) rc = 150;
1149 /*************************************************
1150 * Forced closedown of call *
1151 *************************************************/
1153 /* This function is called from log.c when Exim is dying because of a serious
1154 disaster, and also from some other places. If an incoming non-batched SMTP
1155 channel is open, it swallows the rest of the incoming message if in the DATA
1156 phase, sends the reply string, and gives an error to all subsequent commands
1157 except QUIT. The existence of an SMTP call is detected by the non-NULLness of
1161 message SMTP reply string to send, excluding the code
1167 smtp_closedown(uschar *message)
1169 if (smtp_in == NULL || smtp_batched_input) return;
1170 receive_swallow_smtp();
1171 smtp_printf("421 %s\r\n", message);
1175 switch(smtp_read_command(FALSE))
1181 smtp_printf("221 %s closing connection\r\n", smtp_active_hostname);
1186 smtp_printf("250 Reset OK\r\n");
1190 smtp_printf("421 %s\r\n", message);
1199 /*************************************************
1200 * Set up connection info for logging *
1201 *************************************************/
1203 /* This function is called when logging information about an SMTP connection.
1204 It sets up appropriate source information, depending on the type of connection.
1205 If sender_fullhost is NULL, we are at a very early stage of the connection;
1206 just use the IP address.
1209 Returns: a string describing the connection
1213 smtp_get_connection_info(void)
1215 uschar *hostname = (sender_fullhost == NULL)?
1216 sender_host_address : sender_fullhost;
1219 return string_sprintf("SMTP connection from %s", hostname);
1221 if (sender_host_unknown || sender_host_notsocket)
1222 return string_sprintf("SMTP connection from %s", sender_ident);
1225 return string_sprintf("SMTP connection from %s (via inetd)", hostname);
1227 if ((log_extra_selector & LX_incoming_interface) != 0 &&
1228 interface_address != NULL)
1229 return string_sprintf("SMTP connection from %s I=[%s]:%d", hostname,
1230 interface_address, interface_port);
1232 return string_sprintf("SMTP connection from %s", hostname);
1238 /* Append TLS-related information to a log line
1241 s String under construction: allocated string to extend, or NULL
1242 sizep Pointer to current allocation size (update on return), or NULL
1243 ptrp Pointer to index for new entries in string (update on return), or NULL
1245 Returns: Allocated string or NULL
1248 s_tlslog(uschar * s, int * sizep, int * ptrp)
1250 int size = sizep ? *sizep : 0;
1251 int ptr = ptrp ? *ptrp : 0;
1253 if ((log_extra_selector & LX_tls_cipher) != 0 && tls_in.cipher != NULL)
1254 s = string_append(s, &size, &ptr, 2, US" X=", tls_in.cipher);
1255 if ((log_extra_selector & LX_tls_certificate_verified) != 0 &&
1256 tls_in.cipher != NULL)
1257 s = string_append(s, &size, &ptr, 2, US" CV=",
1258 tls_in.certificate_verified? "yes":"no");
1259 if ((log_extra_selector & LX_tls_peerdn) != 0 && tls_in.peerdn != NULL)
1260 s = string_append(s, &size, &ptr, 3, US" DN=\"",
1261 string_printing(tls_in.peerdn), US"\"");
1262 if ((log_extra_selector & LX_tls_sni) != 0 && tls_in.sni != NULL)
1263 s = string_append(s, &size, &ptr, 3, US" SNI=\"",
1264 string_printing(tls_in.sni), US"\"");
1269 if (sizep) *sizep = size;
1270 if (ptrp) *ptrp = ptr;
1276 /*************************************************
1277 * Log lack of MAIL if so configured *
1278 *************************************************/
1280 /* This function is called when an SMTP session ends. If the log selector
1281 smtp_no_mail is set, write a log line giving some details of what has happened
1282 in the SMTP session.
1289 smtp_log_no_mail(void)
1294 if (smtp_mailcmd_count > 0 || (log_extra_selector & LX_smtp_no_mail) == 0)
1300 if (sender_host_authenticated != NULL)
1302 s = string_append(s, &size, &ptr, 2, US" A=", sender_host_authenticated);
1303 if (authenticated_id != NULL)
1304 s = string_append(s, &size, &ptr, 2, US":", authenticated_id);
1308 s = s_tlslog(s, &size, &ptr);
1311 sep = (smtp_connection_had[SMTP_HBUFF_SIZE-1] != SCH_NONE)?
1312 US" C=..." : US" C=";
1313 for (i = smtp_ch_index; i < SMTP_HBUFF_SIZE; i++)
1315 if (smtp_connection_had[i] != SCH_NONE)
1317 s = string_append(s, &size, &ptr, 2, sep,
1318 smtp_names[smtp_connection_had[i]]);
1323 for (i = 0; i < smtp_ch_index; i++)
1325 s = string_append(s, &size, &ptr, 2, sep, smtp_names[smtp_connection_had[i]]);
1329 if (s != NULL) s[ptr] = 0; else s = US"";
1330 log_write(0, LOG_MAIN, "no MAIL in SMTP connection from %s D=%s%s",
1331 host_and_ident(FALSE),
1332 readconf_printtime( (int) ((long)time(NULL) - (long)smtp_connection_start)),
1338 /*************************************************
1339 * Check HELO line and set sender_helo_name *
1340 *************************************************/
1342 /* Check the format of a HELO line. The data for HELO/EHLO is supposed to be
1343 the domain name of the sending host, or an ip literal in square brackets. The
1344 arrgument is placed in sender_helo_name, which is in malloc store, because it
1345 must persist over multiple incoming messages. If helo_accept_junk is set, this
1346 host is permitted to send any old junk (needed for some broken hosts).
1347 Otherwise, helo_allow_chars can be used for rogue characters in general
1348 (typically people want to let in underscores).
1351 s the data portion of the line (already past any white space)
1353 Returns: TRUE or FALSE
1357 check_helo(uschar *s)
1360 uschar *end = s + Ustrlen(s);
1361 BOOL yield = helo_accept_junk;
1363 /* Discard any previous helo name */
1365 if (sender_helo_name != NULL)
1367 store_free(sender_helo_name);
1368 sender_helo_name = NULL;
1371 /* Skip tests if junk is permitted. */
1375 /* Allow the new standard form for IPv6 address literals, namely,
1376 [IPv6:....], and because someone is bound to use it, allow an equivalent
1377 IPv4 form. Allow plain addresses as well. */
1384 if (strncmpic(s, US"[IPv6:", 6) == 0)
1385 yield = (string_is_ip_address(s+6, NULL) == 6);
1386 else if (strncmpic(s, US"[IPv4:", 6) == 0)
1387 yield = (string_is_ip_address(s+6, NULL) == 4);
1389 yield = (string_is_ip_address(s+1, NULL) != 0);
1394 /* Non-literals must be alpha, dot, hyphen, plus any non-valid chars
1395 that have been configured (usually underscore - sigh). */
1402 if (!isalnum(*s) && *s != '.' && *s != '-' &&
1403 Ustrchr(helo_allow_chars, *s) == NULL)
1413 /* Save argument if OK */
1415 if (yield) sender_helo_name = string_copy_malloc(start);
1423 /*************************************************
1424 * Extract SMTP command option *
1425 *************************************************/
1427 /* This function picks the next option setting off the end of smtp_cmd_data. It
1428 is called for MAIL FROM and RCPT TO commands, to pick off the optional ESMTP
1429 things that can appear there.
1432 name point this at the name
1433 value point this at the data string
1435 Returns: TRUE if found an option
1439 extract_option(uschar **name, uschar **value)
1442 uschar *v = smtp_cmd_data + Ustrlen(smtp_cmd_data) - 1;
1443 while (isspace(*v)) v--;
1445 while (v > smtp_cmd_data && *v != '=' && !isspace(*v)) v--;
1450 while(isalpha(n[-1])) n--;
1451 /* RFC says SP, but TAB seen in wild and other major MTAs accept it */
1452 if (!isspace(n[-1])) return FALSE;
1458 if (v == smtp_cmd_data) return FALSE;
1470 /*************************************************
1471 * Reset for new message *
1472 *************************************************/
1474 /* This function is called whenever the SMTP session is reset from
1475 within either of the setup functions.
1477 Argument: the stacking pool storage reset point
1482 smtp_reset(void *reset_point)
1484 store_reset(reset_point);
1485 recipients_list = NULL;
1486 rcpt_count = rcpt_defer_count = rcpt_fail_count =
1487 raw_recipients_count = recipients_count = recipients_list_max = 0;
1488 cancel_cutthrough_connection("smtp reset");
1489 message_linecount = 0;
1491 acl_added_headers = NULL;
1492 acl_removed_headers = NULL;
1493 queue_only_policy = FALSE;
1494 rcpt_smtp_response = NULL;
1495 rcpt_smtp_response_same = TRUE;
1496 rcpt_in_progress = FALSE;
1497 deliver_freeze = FALSE; /* Can be set by ACL */
1498 freeze_tell = freeze_tell_config; /* Can be set by ACL */
1499 fake_response = OK; /* Can be set by ACL */
1500 #ifdef WITH_CONTENT_SCAN
1501 no_mbox_unspool = FALSE; /* Can be set by ACL */
1503 submission_mode = FALSE; /* Can be set by ACL */
1504 suppress_local_fixups = suppress_local_fixups_default; /* Can be set by ACL */
1505 active_local_from_check = local_from_check; /* Can be set by ACL */
1506 active_local_sender_retain = local_sender_retain; /* Can be set by ACL */
1507 sender_address = NULL;
1508 submission_name = NULL; /* Can be set by ACL */
1509 raw_sender = NULL; /* After SMTP rewrite, before qualifying */
1510 sender_address_unrewritten = NULL; /* Set only after verify rewrite */
1511 sender_verified_list = NULL; /* No senders verified */
1512 memset(sender_address_cache, 0, sizeof(sender_address_cache));
1513 memset(sender_domain_cache, 0, sizeof(sender_domain_cache));
1515 prdr_requested = FALSE;
1517 /* Reset the DSN flags */
1521 authenticated_sender = NULL;
1522 #ifdef EXPERIMENTAL_BRIGHTMAIL
1524 bmi_verdicts = NULL;
1526 #ifndef DISABLE_DKIM
1527 dkim_signers = NULL;
1528 dkim_disable_verify = FALSE;
1529 dkim_collect_input = FALSE;
1531 #ifdef EXPERIMENTAL_SPF
1532 spf_header_comment = NULL;
1533 spf_received = NULL;
1535 spf_smtp_comment = NULL;
1537 #ifdef EXPERIMENTAL_INTERNATIONAL
1538 message_smtputf8 = FALSE;
1540 body_linecount = body_zerocount = 0;
1542 sender_rate = sender_rate_limit = sender_rate_period = NULL;
1543 ratelimiters_mail = NULL; /* Updated by ratelimit ACL condition */
1544 /* Note that ratelimiters_conn persists across resets. */
1546 /* Reset message ACL variables */
1550 /* The message body variables use malloc store. They may be set if this is
1551 not the first message in an SMTP session and the previous message caused them
1552 to be referenced in an ACL. */
1554 if (message_body != NULL)
1556 store_free(message_body);
1557 message_body = NULL;
1560 if (message_body_end != NULL)
1562 store_free(message_body_end);
1563 message_body_end = NULL;
1566 /* Warning log messages are also saved in malloc store. They are saved to avoid
1567 repetition in the same message, but it seems right to repeat them for different
1570 while (acl_warn_logged != NULL)
1572 string_item *this = acl_warn_logged;
1573 acl_warn_logged = acl_warn_logged->next;
1582 /*************************************************
1583 * Initialize for incoming batched SMTP message *
1584 *************************************************/
1586 /* This function is called from smtp_setup_msg() in the case when
1587 smtp_batched_input is true. This happens when -bS is used to pass a whole batch
1588 of messages in one file with SMTP commands between them. All errors must be
1589 reported by sending a message, and only MAIL FROM, RCPT TO, and DATA are
1590 relevant. After an error on a sender, or an invalid recipient, the remainder
1591 of the message is skipped. The value of received_protocol is already set.
1594 Returns: > 0 message successfully started (reached DATA)
1595 = 0 QUIT read or end of file reached
1596 < 0 should not occur
1600 smtp_setup_batch_msg(void)
1603 void *reset_point = store_get(0);
1605 /* Save the line count at the start of each transaction - single commands
1606 like HELO and RSET count as whole transactions. */
1608 bsmtp_transaction_linecount = receive_linecount;
1610 if ((receive_feof)()) return 0; /* Treat EOF as QUIT */
1612 smtp_reset(reset_point); /* Reset for start of message */
1614 /* Deal with SMTP commands. This loop is exited by setting done to a POSITIVE
1615 value. The values are 2 larger than the required yield of the function. */
1620 uschar *recipient = NULL;
1621 int start, end, sender_domain, recipient_domain;
1623 switch(smtp_read_command(FALSE))
1625 /* The HELO/EHLO commands set sender_address_helo if they have
1626 valid data; otherwise they are ignored, except that they do
1627 a reset of the state. */
1632 check_helo(smtp_cmd_data);
1636 smtp_reset(reset_point);
1637 bsmtp_transaction_linecount = receive_linecount;
1641 /* The MAIL FROM command requires an address as an operand. All we
1642 do here is to parse it for syntactic correctness. The form "<>" is
1643 a special case which converts into an empty string. The start/end
1644 pointers in the original are not used further for this address, as
1645 it is the canonical extracted address which is all that is kept. */
1648 if (sender_address != NULL)
1649 /* The function moan_smtp_batch() does not return. */
1650 moan_smtp_batch(smtp_cmd_buffer, "503 Sender already given");
1652 if (smtp_cmd_data[0] == 0)
1653 /* The function moan_smtp_batch() does not return. */
1654 moan_smtp_batch(smtp_cmd_buffer, "501 MAIL FROM must have an address operand");
1656 /* Reset to start of message */
1658 smtp_reset(reset_point);
1660 /* Apply SMTP rewrite */
1662 raw_sender = ((rewrite_existflags & rewrite_smtp) != 0)?
1663 rewrite_one(smtp_cmd_data, rewrite_smtp|rewrite_smtp_sender, NULL, FALSE,
1664 US"", global_rewrite_rules) : smtp_cmd_data;
1666 /* Extract the address; the TRUE flag allows <> as valid */
1669 parse_extract_address(raw_sender, &errmess, &start, &end, &sender_domain,
1672 if (raw_sender == NULL)
1673 /* The function moan_smtp_batch() does not return. */
1674 moan_smtp_batch(smtp_cmd_buffer, "501 %s", errmess);
1676 sender_address = string_copy(raw_sender);
1678 /* Qualify unqualified sender addresses if permitted to do so. */
1680 if (sender_domain == 0 && sender_address[0] != 0 && sender_address[0] != '@')
1682 if (allow_unqualified_sender)
1684 sender_address = rewrite_address_qualify(sender_address, FALSE);
1685 DEBUG(D_receive) debug_printf("unqualified address %s accepted "
1686 "and rewritten\n", raw_sender);
1688 /* The function moan_smtp_batch() does not return. */
1689 else moan_smtp_batch(smtp_cmd_buffer, "501 sender address must contain "
1695 /* The RCPT TO command requires an address as an operand. All we do
1696 here is to parse it for syntactic correctness. There may be any number
1697 of RCPT TO commands, specifying multiple senders. We build them all into
1698 a data structure that is in argc/argv format. The start/end values
1699 given by parse_extract_address are not used, as we keep only the
1700 extracted address. */
1703 if (sender_address == NULL)
1704 /* The function moan_smtp_batch() does not return. */
1705 moan_smtp_batch(smtp_cmd_buffer, "503 No sender yet given");
1707 if (smtp_cmd_data[0] == 0)
1708 /* The function moan_smtp_batch() does not return. */
1709 moan_smtp_batch(smtp_cmd_buffer, "501 RCPT TO must have an address operand");
1711 /* Check maximum number allowed */
1713 if (recipients_max > 0 && recipients_count + 1 > recipients_max)
1714 /* The function moan_smtp_batch() does not return. */
1715 moan_smtp_batch(smtp_cmd_buffer, "%s too many recipients",
1716 recipients_max_reject? "552": "452");
1718 /* Apply SMTP rewrite, then extract address. Don't allow "<>" as a
1719 recipient address */
1721 recipient = ((rewrite_existflags & rewrite_smtp) != 0)?
1722 rewrite_one(smtp_cmd_data, rewrite_smtp, NULL, FALSE, US"",
1723 global_rewrite_rules) : smtp_cmd_data;
1725 /* rfc821_domains = TRUE; << no longer needed */
1726 recipient = parse_extract_address(recipient, &errmess, &start, &end,
1727 &recipient_domain, FALSE);
1728 /* rfc821_domains = FALSE; << no longer needed */
1730 if (recipient == NULL)
1731 /* The function moan_smtp_batch() does not return. */
1732 moan_smtp_batch(smtp_cmd_buffer, "501 %s", errmess);
1734 /* If the recipient address is unqualified, qualify it if permitted. Then
1735 add it to the list of recipients. */
1737 if (recipient_domain == 0)
1739 if (allow_unqualified_recipient)
1741 DEBUG(D_receive) debug_printf("unqualified address %s accepted\n",
1743 recipient = rewrite_address_qualify(recipient, TRUE);
1745 /* The function moan_smtp_batch() does not return. */
1746 else moan_smtp_batch(smtp_cmd_buffer, "501 recipient address must contain "
1749 receive_add_recipient(recipient, -1);
1753 /* The DATA command is legal only if it follows successful MAIL FROM
1754 and RCPT TO commands. This function is complete when a valid DATA
1755 command is encountered. */
1758 if (sender_address == NULL || recipients_count <= 0)
1760 /* The function moan_smtp_batch() does not return. */
1761 if (sender_address == NULL)
1762 moan_smtp_batch(smtp_cmd_buffer,
1763 "503 MAIL FROM:<sender> command must precede DATA");
1765 moan_smtp_batch(smtp_cmd_buffer,
1766 "503 RCPT TO:<recipient> must precede DATA");
1770 done = 3; /* DATA successfully achieved */
1771 message_ended = END_NOTENDED; /* Indicate in middle of message */
1776 /* The VRFY, EXPN, HELP, ETRN, and NOOP commands are ignored. */
1783 bsmtp_transaction_linecount = receive_linecount;
1794 /* The function moan_smtp_batch() does not return. */
1795 moan_smtp_batch(smtp_cmd_buffer, "501 Unexpected argument data");
1800 /* The function moan_smtp_batch() does not return. */
1801 moan_smtp_batch(smtp_cmd_buffer, "501 Unexpected NULL in SMTP command");
1806 /* The function moan_smtp_batch() does not return. */
1807 moan_smtp_batch(smtp_cmd_buffer, "500 Command unrecognized");
1812 return done - 2; /* Convert yield values */
1818 /*************************************************
1819 * Start an SMTP session *
1820 *************************************************/
1822 /* This function is called at the start of an SMTP session. Thereafter,
1823 smtp_setup_msg() is called to initiate each separate message. This
1824 function does host-specific testing, and outputs the banner line.
1827 Returns: FALSE if the session can not continue; something has
1828 gone wrong, or the connection to the host is blocked
1832 smtp_start_session(void)
1836 uschar *user_msg, *log_msg;
1840 smtp_connection_start = time(NULL);
1841 for (smtp_ch_index = 0; smtp_ch_index < SMTP_HBUFF_SIZE; smtp_ch_index++)
1842 smtp_connection_had[smtp_ch_index] = SCH_NONE;
1845 /* Default values for certain variables */
1847 helo_seen = esmtp = helo_accept_junk = FALSE;
1848 smtp_mailcmd_count = 0;
1849 count_nonmail = TRUE_UNSET;
1850 synprot_error_count = unknown_command_count = nonmail_command_count = 0;
1851 smtp_delay_mail = smtp_rlm_base;
1852 auth_advertised = FALSE;
1853 pipelining_advertised = FALSE;
1854 pipelining_enable = TRUE;
1855 sync_cmd_limit = NON_SYNC_CMD_NON_PIPELINING;
1856 smtp_exit_function_called = FALSE; /* For avoiding loop in not-quit exit */
1858 memset(sender_host_cache, 0, sizeof(sender_host_cache));
1860 /* If receiving by -bs from a trusted user, or testing with -bh, we allow
1861 authentication settings from -oMaa to remain in force. */
1863 if (!host_checking && !sender_host_notsocket) sender_host_authenticated = NULL;
1864 authenticated_by = NULL;
1867 tls_in.cipher = tls_in.peerdn = NULL;
1868 tls_in.ourcert = tls_in.peercert = NULL;
1870 tls_in.ocsp = OCSP_NOT_REQ;
1871 tls_advertised = FALSE;
1873 dsn_advertised = FALSE;
1874 #ifdef EXPERIMENTAL_INTERNATIONAL
1875 smtputf8_advertised = FALSE;
1878 /* Reset ACL connection variables */
1882 /* Allow for trailing 0 in the command and data buffers. */
1884 smtp_cmd_buffer = (uschar *)malloc(2*smtp_cmd_buffer_size + 2);
1885 if (smtp_cmd_buffer == NULL)
1886 log_write(0, LOG_MAIN|LOG_PANIC_DIE,
1887 "malloc() failed for SMTP command buffer");
1888 smtp_cmd_buffer[0] = 0;
1889 smtp_data_buffer = smtp_cmd_buffer + smtp_cmd_buffer_size + 1;
1891 /* For batched input, the protocol setting can be overridden from the
1892 command line by a trusted caller. */
1894 if (smtp_batched_input)
1896 if (received_protocol == NULL) received_protocol = US"local-bsmtp";
1899 /* For non-batched SMTP input, the protocol setting is forced here. It will be
1900 reset later if any of EHLO/AUTH/STARTTLS are received. */
1904 (sender_host_address ? protocols : protocols_local) [pnormal];
1906 /* Set up the buffer for inputting using direct read() calls, and arrange to
1907 call the local functions instead of the standard C ones. */
1909 smtp_inbuffer = (uschar *)malloc(in_buffer_size);
1910 if (smtp_inbuffer == NULL)
1911 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "malloc() failed for SMTP input buffer");
1912 receive_getc = smtp_getc;
1913 receive_ungetc = smtp_ungetc;
1914 receive_feof = smtp_feof;
1915 receive_ferror = smtp_ferror;
1916 receive_smtp_buffered = smtp_buffered;
1917 smtp_inptr = smtp_inend = smtp_inbuffer;
1918 smtp_had_eof = smtp_had_error = 0;
1920 /* Set up the message size limit; this may be host-specific */
1922 thismessage_size_limit = expand_string_integer(message_size_limit, TRUE);
1923 if (expand_string_message != NULL)
1925 if (thismessage_size_limit == -1)
1926 log_write(0, LOG_MAIN|LOG_PANIC, "unable to expand message_size_limit: "
1927 "%s", expand_string_message);
1929 log_write(0, LOG_MAIN|LOG_PANIC, "invalid message_size_limit: "
1930 "%s", expand_string_message);
1931 smtp_closedown(US"Temporary local problem - please try later");
1935 /* When a message is input locally via the -bs or -bS options, sender_host_
1936 unknown is set unless -oMa was used to force an IP address, in which case it
1937 is checked like a real remote connection. When -bs is used from inetd, this
1938 flag is not set, causing the sending host to be checked. The code that deals
1939 with IP source routing (if configured) is never required for -bs or -bS and
1940 the flag sender_host_notsocket is used to suppress it.
1942 If smtp_accept_max and smtp_accept_reserve are set, keep some connections in
1943 reserve for certain hosts and/or networks. */
1945 if (!sender_host_unknown)
1948 BOOL reserved_host = FALSE;
1950 /* Look up IP options (source routing info) on the socket if this is not an
1951 -oMa "host", and if any are found, log them and drop the connection.
1953 Linux (and others now, see below) is different to everyone else, so there
1954 has to be some conditional compilation here. Versions of Linux before 2.1.15
1955 used a structure whose name was "options". Somebody finally realized that
1956 this name was silly, and it got changed to "ip_options". I use the
1957 newer name here, but there is a fudge in the script that sets up os.h
1958 to define a macro in older Linux systems.
1960 Sigh. Linux is a fast-moving target. Another generation of Linux uses
1961 glibc 2, which has chosen ip_opts for the structure name. This is now
1962 really a glibc thing rather than a Linux thing, so the condition name
1963 has been changed to reflect this. It is relevant also to GNU/Hurd.
1965 Mac OS 10.x (Darwin) is like the later glibc versions, but without the
1966 setting of the __GLIBC__ macro, so we can't detect it automatically. There's
1967 a special macro defined in the os.h file.
1969 Some DGUX versions on older hardware appear not to support IP options at
1970 all, so there is now a general macro which can be set to cut out this
1973 How to do this properly in IPv6 is not yet known. */
1975 #if !HAVE_IPV6 && !defined(NO_IP_OPTIONS)
1977 #ifdef GLIBC_IP_OPTIONS
1978 #if (!defined __GLIBC__) || (__GLIBC__ < 2)
1983 #elif defined DARWIN_IP_OPTIONS
1989 if (!host_checking && !sender_host_notsocket)
1992 EXIM_SOCKLEN_T optlen = sizeof(struct ip_options) + MAX_IPOPTLEN;
1993 struct ip_options *ipopt = store_get(optlen);
1995 struct ip_opts ipoptblock;
1996 struct ip_opts *ipopt = &ipoptblock;
1997 EXIM_SOCKLEN_T optlen = sizeof(ipoptblock);
1999 struct ipoption ipoptblock;
2000 struct ipoption *ipopt = &ipoptblock;
2001 EXIM_SOCKLEN_T optlen = sizeof(ipoptblock);
2004 /* Occasional genuine failures of getsockopt() have been seen - for
2005 example, "reset by peer". Therefore, just log and give up on this
2006 call, unless the error is ENOPROTOOPT. This error is given by systems
2007 that have the interfaces but not the mechanism - e.g. GNU/Hurd at the time
2008 of writing. So for that error, carry on - we just can't do an IP options
2011 DEBUG(D_receive) debug_printf("checking for IP options\n");
2013 if (getsockopt(fileno(smtp_out), IPPROTO_IP, IP_OPTIONS, (uschar *)(ipopt),
2016 if (errno != ENOPROTOOPT)
2018 log_write(0, LOG_MAIN, "getsockopt() failed from %s: %s",
2019 host_and_ident(FALSE), strerror(errno));
2020 smtp_printf("451 SMTP service not available\r\n");
2025 /* Deal with any IP options that are set. On the systems I have looked at,
2026 the value of MAX_IPOPTLEN has been 40, meaning that there should never be
2027 more logging data than will fit in big_buffer. Nevertheless, after somebody
2028 questioned this code, I've added in some paranoid checking. */
2030 else if (optlen > 0)
2032 uschar *p = big_buffer;
2033 uschar *pend = big_buffer + big_buffer_size;
2034 uschar *opt, *adptr;
2036 struct in_addr addr;
2039 uschar *optstart = (uschar *)(ipopt->__data);
2041 uschar *optstart = (uschar *)(ipopt->ip_opts);
2043 uschar *optstart = (uschar *)(ipopt->ipopt_list);
2046 DEBUG(D_receive) debug_printf("IP options exist\n");
2048 Ustrcpy(p, "IP options on incoming call:");
2051 for (opt = optstart; opt != NULL &&
2052 opt < (uschar *)(ipopt) + optlen;)
2066 if (!string_format(p, pend-p, " %s [@%s",
2067 (*opt == IPOPT_SSRR)? "SSRR" : "LSRR",
2069 inet_ntoa(*((struct in_addr *)(&(ipopt->faddr))))))
2071 inet_ntoa(ipopt->ip_dst)))
2073 inet_ntoa(ipopt->ipopt_dst)))
2081 optcount = (opt[1] - 3) / sizeof(struct in_addr);
2083 while (optcount-- > 0)
2085 memcpy(&addr, adptr, sizeof(addr));
2086 if (!string_format(p, pend - p - 1, "%s%s",
2087 (optcount == 0)? ":" : "@", inet_ntoa(addr)))
2093 adptr += sizeof(struct in_addr);
2102 if (pend - p < 4 + 3*opt[1]) { opt = NULL; break; }
2105 for (i = 0; i < opt[1]; i++)
2107 sprintf(CS p, "%2.2x ", opt[i]);
2118 log_write(0, LOG_MAIN, "%s", big_buffer);
2120 /* Refuse any call with IP options. This is what tcpwrappers 7.5 does. */
2122 log_write(0, LOG_MAIN|LOG_REJECT,
2123 "connection from %s refused (IP options)", host_and_ident(FALSE));
2125 smtp_printf("554 SMTP service not available\r\n");
2129 /* Length of options = 0 => there are no options */
2131 else DEBUG(D_receive) debug_printf("no IP options found\n");
2133 #endif /* HAVE_IPV6 && !defined(NO_IP_OPTIONS) */
2135 /* Set keep-alive in socket options. The option is on by default. This
2136 setting is an attempt to get rid of some hanging connections that stick in
2137 read() when the remote end (usually a dialup) goes away. */
2139 if (smtp_accept_keepalive && !sender_host_notsocket)
2140 ip_keepalive(fileno(smtp_out), sender_host_address, FALSE);
2142 /* If the current host matches host_lookup, set the name by doing a
2143 reverse lookup. On failure, sender_host_name will be NULL and
2144 host_lookup_failed will be TRUE. This may or may not be serious - optional
2147 if (verify_check_host(&host_lookup) == OK)
2149 (void)host_name_lookup();
2150 host_build_sender_fullhost();
2153 /* Delay this until we have the full name, if it is looked up. */
2155 set_process_info("handling incoming connection from %s",
2156 host_and_ident(FALSE));
2158 /* Expand smtp_receive_timeout, if needed */
2160 if (smtp_receive_timeout_s)
2163 if ( !(exp = expand_string(smtp_receive_timeout_s))
2165 || (smtp_receive_timeout = readconf_readtime(exp, 0, FALSE)) < 0
2167 log_write(0, LOG_MAIN|LOG_PANIC,
2168 "bad value for smtp_receive_timeout: '%s'", exp ? exp : US"");
2171 /* Start up TLS if tls_on_connect is set. This is for supporting the legacy
2172 smtps port for use with older style SSL MTAs. */
2175 if (tls_in.on_connect && tls_server_start(tls_require_ciphers) != OK)
2179 /* Test for explicit connection rejection */
2181 if (verify_check_host(&host_reject_connection) == OK)
2183 log_write(L_connection_reject, LOG_MAIN|LOG_REJECT, "refused connection "
2184 "from %s (host_reject_connection)", host_and_ident(FALSE));
2185 smtp_printf("554 SMTP service not available\r\n");
2189 /* Test with TCP Wrappers if so configured. There is a problem in that
2190 hosts_ctl() returns 0 (deny) under a number of system failure circumstances,
2191 such as disks dying. In these cases, it is desirable to reject with a 4xx
2192 error instead of a 5xx error. There isn't a "right" way to detect such
2193 problems. The following kludge is used: errno is zeroed before calling
2194 hosts_ctl(). If the result is "reject", a 5xx error is given only if the
2195 value of errno is 0 or ENOENT (which happens if /etc/hosts.{allow,deny} does
2198 #ifdef USE_TCP_WRAPPERS
2200 tcp_wrappers_name = expand_string(tcp_wrappers_daemon_name);
2201 if (tcp_wrappers_name == NULL)
2203 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "Expansion of \"%s\" "
2204 "(tcp_wrappers_name) failed: %s", string_printing(tcp_wrappers_name),
2205 expand_string_message);
2207 if (!hosts_ctl(tcp_wrappers_name,
2208 (sender_host_name == NULL)? STRING_UNKNOWN : CS sender_host_name,
2209 (sender_host_address == NULL)? STRING_UNKNOWN : CS sender_host_address,
2210 (sender_ident == NULL)? STRING_UNKNOWN : CS sender_ident))
2212 if (errno == 0 || errno == ENOENT)
2214 HDEBUG(D_receive) debug_printf("tcp wrappers rejection\n");
2215 log_write(L_connection_reject,
2216 LOG_MAIN|LOG_REJECT, "refused connection from %s "
2217 "(tcp wrappers)", host_and_ident(FALSE));
2218 smtp_printf("554 SMTP service not available\r\n");
2222 int save_errno = errno;
2223 HDEBUG(D_receive) debug_printf("tcp wrappers rejected with unexpected "
2224 "errno value %d\n", save_errno);
2225 log_write(L_connection_reject,
2226 LOG_MAIN|LOG_REJECT, "temporarily refused connection from %s "
2227 "(tcp wrappers errno=%d)", host_and_ident(FALSE), save_errno);
2228 smtp_printf("451 Temporary local problem - please try later\r\n");
2234 /* Check for reserved slots. The value of smtp_accept_count has already been
2235 incremented to include this process. */
2237 if (smtp_accept_max > 0 &&
2238 smtp_accept_count > smtp_accept_max - smtp_accept_reserve)
2240 if ((rc = verify_check_host(&smtp_reserve_hosts)) != OK)
2242 log_write(L_connection_reject,
2243 LOG_MAIN, "temporarily refused connection from %s: not in "
2244 "reserve list: connected=%d max=%d reserve=%d%s",
2245 host_and_ident(FALSE), smtp_accept_count - 1, smtp_accept_max,
2246 smtp_accept_reserve, (rc == DEFER)? " (lookup deferred)" : "");
2247 smtp_printf("421 %s: Too many concurrent SMTP connections; "
2248 "please try again later\r\n", smtp_active_hostname);
2251 reserved_host = TRUE;
2254 /* If a load level above which only messages from reserved hosts are
2255 accepted is set, check the load. For incoming calls via the daemon, the
2256 check is done in the superior process if there are no reserved hosts, to
2257 save a fork. In all cases, the load average will already be available
2258 in a global variable at this point. */
2260 if (smtp_load_reserve >= 0 &&
2261 load_average > smtp_load_reserve &&
2263 verify_check_host(&smtp_reserve_hosts) != OK)
2265 log_write(L_connection_reject,
2266 LOG_MAIN, "temporarily refused connection from %s: not in "
2267 "reserve list and load average = %.2f", host_and_ident(FALSE),
2268 (double)load_average/1000.0);
2269 smtp_printf("421 %s: Too much load; please try again later\r\n",
2270 smtp_active_hostname);
2274 /* Determine whether unqualified senders or recipients are permitted
2275 for this host. Unfortunately, we have to do this every time, in order to
2276 set the flags so that they can be inspected when considering qualifying
2277 addresses in the headers. For a site that permits no qualification, this
2278 won't take long, however. */
2280 allow_unqualified_sender =
2281 verify_check_host(&sender_unqualified_hosts) == OK;
2283 allow_unqualified_recipient =
2284 verify_check_host(&recipient_unqualified_hosts) == OK;
2286 /* Determine whether HELO/EHLO is required for this host. The requirement
2287 can be hard or soft. */
2289 helo_required = verify_check_host(&helo_verify_hosts) == OK;
2291 helo_verify = verify_check_host(&helo_try_verify_hosts) == OK;
2293 /* Determine whether this hosts is permitted to send syntactic junk
2294 after a HELO or EHLO command. */
2296 helo_accept_junk = verify_check_host(&helo_accept_junk_hosts) == OK;
2299 /* For batch SMTP input we are now done. */
2301 if (smtp_batched_input) return TRUE;
2303 #ifdef EXPERIMENTAL_PROXY
2304 /* If valid Proxy Protocol source is connecting, set up session.
2305 * Failure will not allow any SMTP function other than QUIT. */
2306 proxy_session = FALSE;
2307 proxy_session_failed = FALSE;
2308 if (check_proxy_protocol_host())
2310 if (setup_proxy_protocol_host() == FALSE)
2312 proxy_session_failed = TRUE;
2314 debug_printf("Failure to extract proxied host, only QUIT allowed\n");
2318 sender_host_name = NULL;
2319 (void)host_name_lookup();
2320 host_build_sender_fullhost();
2325 /* Run the ACL if it exists */
2328 if (acl_smtp_connect != NULL)
2331 rc = acl_check(ACL_WHERE_CONNECT, NULL, acl_smtp_connect, &user_msg,
2335 (void)smtp_handle_acl_fail(ACL_WHERE_CONNECT, rc, user_msg, log_msg);
2340 /* Output the initial message for a two-way SMTP connection. It may contain
2341 newlines, which then cause a multi-line response to be given. */
2343 code = US"220"; /* Default status code */
2344 esc = US""; /* Default extended status code */
2345 esclen = 0; /* Length of esc */
2347 if (user_msg == NULL)
2349 s = expand_string(smtp_banner);
2351 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "Expansion of \"%s\" (smtp_banner) "
2352 "failed: %s", smtp_banner, expand_string_message);
2358 smtp_message_code(&code, &codelen, &s, NULL);
2362 esclen = codelen - 4;
2366 /* Remove any terminating newlines; might as well remove trailing space too */
2369 while (p > s && isspace(p[-1])) p--;
2372 /* It seems that CC:Mail is braindead, and assumes that the greeting message
2373 is all contained in a single IP packet. The original code wrote out the
2374 greeting using several calls to fprint/fputc, and on busy servers this could
2375 cause it to be split over more than one packet - which caused CC:Mail to fall
2376 over when it got the second part of the greeting after sending its first
2377 command. Sigh. To try to avoid this, build the complete greeting message
2378 first, and output it in one fell swoop. This gives a better chance of it
2379 ending up as a single packet. */
2381 ss = store_get(size);
2385 do /* At least once, in case we have an empty string */
2388 uschar *linebreak = Ustrchr(p, '\n');
2389 ss = string_cat(ss, &size, &ptr, code, 3);
2390 if (linebreak == NULL)
2393 ss = string_cat(ss, &size, &ptr, US" ", 1);
2397 len = linebreak - p;
2398 ss = string_cat(ss, &size, &ptr, US"-", 1);
2400 ss = string_cat(ss, &size, &ptr, esc, esclen);
2401 ss = string_cat(ss, &size, &ptr, p, len);
2402 ss = string_cat(ss, &size, &ptr, US"\r\n", 2);
2404 if (linebreak != NULL) p++;
2408 ss[ptr] = 0; /* string_cat leaves room for this */
2410 /* Before we write the banner, check that there is no input pending, unless
2411 this synchronisation check is disabled. */
2415 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP protocol "
2416 "synchronization error (input sent without waiting for greeting): "
2417 "rejected connection from %s input=\"%s\"", host_and_ident(TRUE),
2418 string_printing(smtp_inptr));
2419 smtp_printf("554 SMTP synchronization error\r\n");
2423 /* Now output the banner */
2425 smtp_printf("%s", ss);
2433 /*************************************************
2434 * Handle SMTP syntax and protocol errors *
2435 *************************************************/
2437 /* Write to the log for SMTP syntax errors in incoming commands, if configured
2438 to do so. Then transmit the error response. The return value depends on the
2439 number of syntax and protocol errors in this SMTP session.
2442 type error type, given as a log flag bit
2443 code response code; <= 0 means don't send a response
2444 data data to reflect in the response (can be NULL)
2445 errmess the error message
2447 Returns: -1 limit of syntax/protocol errors NOT exceeded
2448 +1 limit of syntax/protocol errors IS exceeded
2450 These values fit in with the values of the "done" variable in the main
2451 processing loop in smtp_setup_msg(). */
2454 synprot_error(int type, int code, uschar *data, uschar *errmess)
2458 log_write(type, LOG_MAIN, "SMTP %s error in \"%s\" %s %s",
2459 (type == L_smtp_syntax_error)? "syntax" : "protocol",
2460 string_printing(smtp_cmd_buffer), host_and_ident(TRUE), errmess);
2462 if (++synprot_error_count > smtp_max_synprot_errors)
2465 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
2466 "syntax or protocol errors (last command was \"%s\")",
2467 host_and_ident(FALSE), string_printing(smtp_cmd_buffer));
2472 smtp_printf("%d%c%s%s%s\r\n", code, (yield == 1)? '-' : ' ',
2473 (data == NULL)? US"" : data, (data == NULL)? US"" : US": ", errmess);
2475 smtp_printf("%d Too many syntax or protocol errors\r\n", code);
2484 /*************************************************
2485 * Log incomplete transactions *
2486 *************************************************/
2488 /* This function is called after a transaction has been aborted by RSET, QUIT,
2489 connection drops or other errors. It logs the envelope information received
2490 so far in order to preserve address verification attempts.
2492 Argument: string to indicate what aborted the transaction
2497 incomplete_transaction_log(uschar *what)
2499 if (sender_address == NULL || /* No transaction in progress */
2500 (log_write_selector & L_smtp_incomplete_transaction) == 0 /* Not logging */
2503 /* Build list of recipients for logging */
2505 if (recipients_count > 0)
2508 raw_recipients = store_get(recipients_count * sizeof(uschar *));
2509 for (i = 0; i < recipients_count; i++)
2510 raw_recipients[i] = recipients_list[i].address;
2511 raw_recipients_count = recipients_count;
2514 log_write(L_smtp_incomplete_transaction, LOG_MAIN|LOG_SENDER|LOG_RECIPIENTS,
2515 "%s incomplete transaction (%s)", host_and_ident(TRUE), what);
2521 /*************************************************
2522 * Send SMTP response, possibly multiline *
2523 *************************************************/
2525 /* There are, it seems, broken clients out there that cannot handle multiline
2526 responses. If no_multiline_responses is TRUE (it can be set from an ACL), we
2527 output nothing for non-final calls, and only the first line for anything else.
2530 code SMTP code, may involve extended status codes
2531 codelen length of smtp code; if > 4 there's an ESC
2532 final FALSE if the last line isn't the final line
2533 msg message text, possibly containing newlines
2539 smtp_respond(uschar* code, int codelen, BOOL final, uschar *msg)
2544 if (!final && no_multiline_responses) return;
2549 esclen = codelen - 4;
2552 /* If this is the first output for a (non-batch) RCPT command, see if all RCPTs
2553 have had the same. Note: this code is also present in smtp_printf(). It would
2554 be tidier to have it only in one place, but when it was added, it was easier to
2555 do it that way, so as not to have to mess with the code for the RCPT command,
2556 which sometimes uses smtp_printf() and sometimes smtp_respond(). */
2558 if (rcpt_in_progress)
2560 if (rcpt_smtp_response == NULL)
2561 rcpt_smtp_response = string_copy(msg);
2562 else if (rcpt_smtp_response_same &&
2563 Ustrcmp(rcpt_smtp_response, msg) != 0)
2564 rcpt_smtp_response_same = FALSE;
2565 rcpt_in_progress = FALSE;
2568 /* Not output the message, splitting it up into multiple lines if necessary. */
2572 uschar *nl = Ustrchr(msg, '\n');
2575 smtp_printf("%.3s%c%.*s%s\r\n", code, final? ' ':'-', esclen, esc, msg);
2578 else if (nl[1] == 0 || no_multiline_responses)
2580 smtp_printf("%.3s%c%.*s%.*s\r\n", code, final? ' ':'-', esclen, esc,
2581 (int)(nl - msg), msg);
2586 smtp_printf("%.3s-%.*s%.*s\r\n", code, esclen, esc, (int)(nl - msg), msg);
2588 while (isspace(*msg)) msg++;
2596 /*************************************************
2597 * Parse user SMTP message *
2598 *************************************************/
2600 /* This function allows for user messages overriding the response code details
2601 by providing a suitable response code string at the start of the message
2602 user_msg. Check the message for starting with a response code and optionally an
2603 extended status code. If found, check that the first digit is valid, and if so,
2604 change the code pointer and length to use the replacement. An invalid code
2605 causes a panic log; in this case, if the log messages is the same as the user
2606 message, we must also adjust the value of the log message to show the code that
2607 is actually going to be used (the original one).
2609 This function is global because it is called from receive.c as well as within
2612 Note that the code length returned includes the terminating whitespace
2613 character, which is always included in the regex match.
2616 code SMTP code, may involve extended status codes
2617 codelen length of smtp code; if > 4 there's an ESC
2619 log_msg optional log message, to be adjusted with the new SMTP code
2625 smtp_message_code(uschar **code, int *codelen, uschar **msg, uschar **log_msg)
2630 if (msg == NULL || *msg == NULL) return;
2632 n = pcre_exec(regex_smtp_code, NULL, CS *msg, Ustrlen(*msg), 0,
2633 PCRE_EOPT, ovector, sizeof(ovector)/sizeof(int));
2636 if ((*msg)[0] != (*code)[0])
2638 log_write(0, LOG_MAIN|LOG_PANIC, "configured error code starts with "
2639 "incorrect digit (expected %c) in \"%s\"", (*code)[0], *msg);
2640 if (log_msg != NULL && *log_msg == *msg)
2641 *log_msg = string_sprintf("%s %s", *code, *log_msg + ovector[1]);
2646 *codelen = ovector[1]; /* Includes final space */
2648 *msg += ovector[1]; /* Chop the code off the message */
2655 /*************************************************
2656 * Handle an ACL failure *
2657 *************************************************/
2659 /* This function is called when acl_check() fails. As well as calls from within
2660 this module, it is called from receive.c for an ACL after DATA. It sorts out
2661 logging the incident, and sets up the error response. A message containing
2662 newlines is turned into a multiline SMTP response, but for logging, only the
2665 There's a table of default permanent failure response codes to use in
2666 globals.c, along with the table of names. VFRY is special. Despite RFC1123 it
2667 defaults disabled in Exim. However, discussion in connection with RFC 821bis
2668 (aka RFC 2821) has concluded that the response should be 252 in the disabled
2669 state, because there are broken clients that try VRFY before RCPT. A 5xx
2670 response should be given only when the address is positively known to be
2671 undeliverable. Sigh. Also, for ETRN, 458 is given on refusal, and for AUTH,
2674 From Exim 4.63, it is possible to override the response code details by
2675 providing a suitable response code string at the start of the message provided
2676 in user_msg. The code's first digit is checked for validity.
2679 where where the ACL was called from
2681 user_msg a message that can be included in an SMTP response
2682 log_msg a message for logging
2684 Returns: 0 in most cases
2685 2 if the failure code was FAIL_DROP, in which case the
2686 SMTP connection should be dropped (this value fits with the
2687 "done" variable in smtp_setup_msg() below)
2691 smtp_handle_acl_fail(int where, int rc, uschar *user_msg, uschar *log_msg)
2693 BOOL drop = rc == FAIL_DROP;
2697 uschar *sender_info = US"";
2699 #ifdef WITH_CONTENT_SCAN
2700 (where == ACL_WHERE_MIME)? US"during MIME ACL checks" :
2702 (where == ACL_WHERE_PREDATA)? US"DATA" :
2703 (where == ACL_WHERE_DATA)? US"after DATA" :
2704 #ifndef DISABLE_PRDR
2705 (where == ACL_WHERE_PRDR)? US"after DATA PRDR" :
2707 (smtp_cmd_data == NULL)?
2708 string_sprintf("%s in \"connect\" ACL", acl_wherenames[where]) :
2709 string_sprintf("%s %s", acl_wherenames[where], smtp_cmd_data);
2711 if (drop) rc = FAIL;
2713 /* Set the default SMTP code, and allow a user message to change it. */
2715 smtp_code = (rc != FAIL)? US"451" : acl_wherecodes[where];
2716 smtp_message_code(&smtp_code, &codelen, &user_msg, &log_msg);
2718 /* We used to have sender_address here; however, there was a bug that was not
2719 updating sender_address after a rewrite during a verify. When this bug was
2720 fixed, sender_address at this point became the rewritten address. I'm not sure
2721 this is what should be logged, so I've changed to logging the unrewritten
2722 address to retain backward compatibility. */
2724 #ifndef WITH_CONTENT_SCAN
2725 if (where == ACL_WHERE_RCPT || where == ACL_WHERE_DATA)
2727 if (where == ACL_WHERE_RCPT || where == ACL_WHERE_DATA || where == ACL_WHERE_MIME)
2730 sender_info = string_sprintf("F=<%s>%s%s%s%s ",
2731 sender_address_unrewritten ? sender_address_unrewritten : sender_address,
2732 sender_host_authenticated ? US" A=" : US"",
2733 sender_host_authenticated ? sender_host_authenticated : US"",
2734 sender_host_authenticated && authenticated_id ? US":" : US"",
2735 sender_host_authenticated && authenticated_id ? authenticated_id : US""
2739 /* If there's been a sender verification failure with a specific message, and
2740 we have not sent a response about it yet, do so now, as a preliminary line for
2741 failures, but not defers. However, always log it for defer, and log it for fail
2742 unless the sender_verify_fail log selector has been turned off. */
2744 if (sender_verified_failed != NULL &&
2745 !testflag(sender_verified_failed, af_sverify_told))
2747 BOOL save_rcpt_in_progress = rcpt_in_progress;
2748 rcpt_in_progress = FALSE; /* So as not to treat these as the error */
2750 setflag(sender_verified_failed, af_sverify_told);
2752 if (rc != FAIL || (log_extra_selector & LX_sender_verify_fail) != 0)
2753 log_write(0, LOG_MAIN|LOG_REJECT, "%s sender verify %s for <%s>%s",
2754 host_and_ident(TRUE),
2755 ((sender_verified_failed->special_action & 255) == DEFER)? "defer":"fail",
2756 sender_verified_failed->address,
2757 (sender_verified_failed->message == NULL)? US"" :
2758 string_sprintf(": %s", sender_verified_failed->message));
2760 if (rc == FAIL && sender_verified_failed->user_message != NULL)
2761 smtp_respond(smtp_code, codelen, FALSE, string_sprintf(
2762 testflag(sender_verified_failed, af_verify_pmfail)?
2763 "Postmaster verification failed while checking <%s>\n%s\n"
2764 "Several RFCs state that you are required to have a postmaster\n"
2765 "mailbox for each mail domain. This host does not accept mail\n"
2766 "from domains whose servers reject the postmaster address."
2768 testflag(sender_verified_failed, af_verify_nsfail)?
2769 "Callback setup failed while verifying <%s>\n%s\n"
2770 "The initial connection, or a HELO or MAIL FROM:<> command was\n"
2771 "rejected. Refusing MAIL FROM:<> does not help fight spam, disregards\n"
2772 "RFC requirements, and stops you from receiving standard bounce\n"
2773 "messages. This host does not accept mail from domains whose servers\n"
2776 "Verification failed for <%s>\n%s",
2777 sender_verified_failed->address,
2778 sender_verified_failed->user_message));
2780 rcpt_in_progress = save_rcpt_in_progress;
2783 /* Sort out text for logging */
2785 log_msg = (log_msg == NULL)? US"" : string_sprintf(": %s", log_msg);
2786 lognl = Ustrchr(log_msg, '\n');
2787 if (lognl != NULL) *lognl = 0;
2789 /* Send permanent failure response to the command, but the code used isn't
2790 always a 5xx one - see comments at the start of this function. If the original
2791 rc was FAIL_DROP we drop the connection and yield 2. */
2793 if (rc == FAIL) smtp_respond(smtp_code, codelen, TRUE, (user_msg == NULL)?
2794 US"Administrative prohibition" : user_msg);
2796 /* Send temporary failure response to the command. Don't give any details,
2797 unless acl_temp_details is set. This is TRUE for a callout defer, a "defer"
2798 verb, and for a header verify when smtp_return_error_details is set.
2800 This conditional logic is all somewhat of a mess because of the odd
2801 interactions between temp_details and return_error_details. One day it should
2802 be re-implemented in a tidier fashion. */
2806 if (acl_temp_details && user_msg != NULL)
2808 if (smtp_return_error_details &&
2809 sender_verified_failed != NULL &&
2810 sender_verified_failed->message != NULL)
2812 smtp_respond(smtp_code, codelen, FALSE, sender_verified_failed->message);
2814 smtp_respond(smtp_code, codelen, TRUE, user_msg);
2817 smtp_respond(smtp_code, codelen, TRUE,
2818 US"Temporary local problem - please try later");
2821 /* Log the incident to the logs that are specified by log_reject_target
2822 (default main, reject). This can be empty to suppress logging of rejections. If
2823 the connection is not forcibly to be dropped, return 0. Otherwise, log why it
2824 is closing if required and return 2. */
2826 if (log_reject_target != 0)
2829 uschar * s = s_tlslog(NULL, NULL, NULL);
2834 log_write(0, log_reject_target, "%s%s %s%srejected %s%s",
2835 host_and_ident(TRUE), s,
2836 sender_info, (rc == FAIL)? US"" : US"temporarily ", what, log_msg);
2839 if (!drop) return 0;
2841 log_write(L_smtp_connection, LOG_MAIN, "%s closed by DROP in ACL",
2842 smtp_get_connection_info());
2844 /* Run the not-quit ACL, but without any custom messages. This should not be a
2845 problem, because we get here only if some other ACL has issued "drop", and
2846 in that case, *its* custom messages will have been used above. */
2848 smtp_notquit_exit(US"acl-drop", NULL, NULL);
2855 /*************************************************
2856 * Handle SMTP exit when QUIT is not given *
2857 *************************************************/
2859 /* This function provides a logging/statistics hook for when an SMTP connection
2860 is dropped on the floor or the other end goes away. It's a global function
2861 because it's called from receive.c as well as this module. As well as running
2862 the NOTQUIT ACL, if there is one, this function also outputs a final SMTP
2863 response, either with a custom message from the ACL, or using a default. There
2864 is one case, however, when no message is output - after "drop". In that case,
2865 the ACL that obeyed "drop" has already supplied the custom message, and NULL is
2866 passed to this function.
2868 In case things go wrong while processing this function, causing an error that
2869 may re-enter this funtion, there is a recursion check.
2872 reason What $smtp_notquit_reason will be set to in the ACL;
2873 if NULL, the ACL is not run
2874 code The error code to return as part of the response
2875 defaultrespond The default message if there's no user_msg
2881 smtp_notquit_exit(uschar *reason, uschar *code, uschar *defaultrespond, ...)
2884 uschar *user_msg = NULL;
2885 uschar *log_msg = NULL;
2887 /* Check for recursive acll */
2889 if (smtp_exit_function_called)
2891 log_write(0, LOG_PANIC, "smtp_notquit_exit() called more than once (%s)",
2895 smtp_exit_function_called = TRUE;
2897 /* Call the not-QUIT ACL, if there is one, unless no reason is given. */
2899 if (acl_smtp_notquit != NULL && reason != NULL)
2901 smtp_notquit_reason = reason;
2902 rc = acl_check(ACL_WHERE_NOTQUIT, NULL, acl_smtp_notquit, &user_msg,
2905 log_write(0, LOG_MAIN|LOG_PANIC, "ACL for not-QUIT returned ERROR: %s",
2909 /* Write an SMTP response if we are expected to give one. As the default
2910 responses are all internal, they should always fit in the buffer, but code a
2911 warning, just in case. Note that string_vformat() still leaves a complete
2912 string, even if it is incomplete. */
2914 if (code != NULL && defaultrespond != NULL)
2916 if (user_msg == NULL)
2920 va_start(ap, defaultrespond);
2921 if (!string_vformat(buffer, sizeof(buffer), CS defaultrespond, ap))
2922 log_write(0, LOG_MAIN|LOG_PANIC, "string too large in smtp_notquit_exit()");
2923 smtp_printf("%s %s\r\n", code, buffer);
2927 smtp_respond(code, 3, TRUE, user_msg);
2935 /*************************************************
2936 * Verify HELO argument *
2937 *************************************************/
2939 /* This function is called if helo_verify_hosts or helo_try_verify_hosts is
2940 matched. It is also called from ACL processing if verify = helo is used and
2941 verification was not previously tried (i.e. helo_try_verify_hosts was not
2942 matched). The result of its processing is to set helo_verified and
2943 helo_verify_failed. These variables should both be FALSE for this function to
2946 Note that EHLO/HELO is legitimately allowed to quote an address literal. Allow
2947 for IPv6 ::ffff: literals.
2950 Returns: TRUE if testing was completed;
2951 FALSE on a temporary failure
2955 smtp_verify_helo(void)
2959 HDEBUG(D_receive) debug_printf("verifying EHLO/HELO argument \"%s\"\n",
2962 if (sender_helo_name == NULL)
2964 HDEBUG(D_receive) debug_printf("no EHLO/HELO command was issued\n");
2967 /* Deal with the case of -bs without an IP address */
2969 else if (sender_host_address == NULL)
2971 HDEBUG(D_receive) debug_printf("no client IP address: assume success\n");
2972 helo_verified = TRUE;
2975 /* Deal with the more common case when there is a sending IP address */
2977 else if (sender_helo_name[0] == '[')
2979 helo_verified = Ustrncmp(sender_helo_name+1, sender_host_address,
2980 Ustrlen(sender_host_address)) == 0;
2985 if (strncmpic(sender_host_address, US"::ffff:", 7) == 0)
2986 helo_verified = Ustrncmp(sender_helo_name + 1,
2987 sender_host_address + 7, Ustrlen(sender_host_address) - 7) == 0;
2992 { if (helo_verified) debug_printf("matched host address\n"); }
2995 /* Do a reverse lookup if one hasn't already given a positive or negative
2996 response. If that fails, or the name doesn't match, try checking with a forward
3001 if (sender_host_name == NULL && !host_lookup_failed)
3002 yield = host_name_lookup() != DEFER;
3004 /* If a host name is known, check it and all its aliases. */
3006 if (sender_host_name != NULL)
3008 helo_verified = strcmpic(sender_host_name, sender_helo_name) == 0;
3012 HDEBUG(D_receive) debug_printf("matched host name\n");
3016 uschar **aliases = sender_host_aliases;
3017 while (*aliases != NULL)
3019 helo_verified = strcmpic(*aliases++, sender_helo_name) == 0;
3020 if (helo_verified) break;
3025 debug_printf("matched alias %s\n", *(--aliases));
3030 /* Final attempt: try a forward lookup of the helo name */
3036 h.name = sender_helo_name;
3040 HDEBUG(D_receive) debug_printf("getting IP address for %s\n",
3042 rc = host_find_byname(&h, NULL, 0, NULL, TRUE);
3043 if (rc == HOST_FOUND || rc == HOST_FOUND_LOCAL)
3048 if (Ustrcmp(hh->address, sender_host_address) == 0)
3050 helo_verified = TRUE;
3052 debug_printf("IP address for %s matches calling address\n",
3062 if (!helo_verified) helo_verify_failed = TRUE; /* We've tried ... */
3069 /*************************************************
3070 * Send user response message *
3071 *************************************************/
3073 /* This function is passed a default response code and a user message. It calls
3074 smtp_message_code() to check and possibly modify the response code, and then
3075 calls smtp_respond() to transmit the response. I put this into a function
3076 just to avoid a lot of repetition.
3079 code the response code
3080 user_msg the user message
3086 smtp_user_msg(uschar *code, uschar *user_msg)
3089 smtp_message_code(&code, &len, &user_msg, NULL);
3090 smtp_respond(code, len, TRUE, user_msg);
3095 /*************************************************
3096 * Initialize for SMTP incoming message *
3097 *************************************************/
3099 /* This function conducts the initial dialogue at the start of an incoming SMTP
3100 message, and builds a list of recipients. However, if the incoming message
3101 is part of a batch (-bS option) a separate function is called since it would
3102 be messy having tests splattered about all over this function. This function
3103 therefore handles the case where interaction is occurring. The input and output
3104 files are set up in smtp_in and smtp_out.
3106 The global recipients_list is set to point to a vector of recipient_item
3107 blocks, whose number is given by recipients_count. This is extended by the
3108 receive_add_recipient() function. The global variable sender_address is set to
3109 the sender's address. The yield is +1 if a message has been successfully
3110 started, 0 if a QUIT command was encountered or the connection was refused from
3111 the particular host, or -1 if the connection was lost.
3115 Returns: > 0 message successfully started (reached DATA)
3116 = 0 QUIT read or end of file reached or call refused
3121 smtp_setup_msg(void)
3124 BOOL toomany = FALSE;
3125 BOOL discarded = FALSE;
3126 BOOL last_was_rej_mail = FALSE;
3127 BOOL last_was_rcpt = FALSE;
3128 void *reset_point = store_get(0);
3130 DEBUG(D_receive) debug_printf("smtp_setup_msg entered\n");
3132 /* Reset for start of new message. We allow one RSET not to be counted as a
3133 nonmail command, for those MTAs that insist on sending it between every
3134 message. Ditto for EHLO/HELO and for STARTTLS, to allow for going in and out of
3135 TLS between messages (an Exim client may do this if it has messages queued up
3136 for the host). Note: we do NOT reset AUTH at this point. */
3138 smtp_reset(reset_point);
3139 message_ended = END_NOTSTARTED;
3141 cmd_list[CMD_LIST_RSET].is_mail_cmd = TRUE;
3142 cmd_list[CMD_LIST_HELO].is_mail_cmd = TRUE;
3143 cmd_list[CMD_LIST_EHLO].is_mail_cmd = TRUE;
3145 cmd_list[CMD_LIST_STARTTLS].is_mail_cmd = TRUE;
3148 /* Set the local signal handler for SIGTERM - it tries to end off tidily */
3150 os_non_restarting_signal(SIGTERM, command_sigterm_handler);
3152 /* Batched SMTP is handled in a different function. */
3154 if (smtp_batched_input) return smtp_setup_batch_msg();
3156 /* Deal with SMTP commands. This loop is exited by setting done to a POSITIVE
3157 value. The values are 2 larger than the required yield of the function. */
3161 const uschar **argv;
3162 uschar *etrn_command;
3163 uschar *etrn_serialize_key;
3165 uschar *log_msg, *smtp_code;
3166 uschar *user_msg = NULL;
3167 uschar *recipient = NULL;
3168 uschar *hello = NULL;
3169 const uschar *set_id = NULL;
3171 BOOL was_rej_mail = FALSE;
3172 BOOL was_rcpt = FALSE;
3173 void (*oldsignal)(int);
3175 int start, end, sender_domain, recipient_domain;
3179 uschar *orcpt = NULL;
3182 switch(smtp_read_command(TRUE))
3184 /* The AUTH command is not permitted to occur inside a transaction, and may
3185 occur successfully only once per connection. Actually, that isn't quite
3186 true. When TLS is started, all previous information about a connection must
3187 be discarded, so a new AUTH is permitted at that time.
3189 AUTH may only be used when it has been advertised. However, it seems that
3190 there are clients that send AUTH when it hasn't been advertised, some of
3191 them even doing this after HELO. And there are MTAs that accept this. Sigh.
3192 So there's a get-out that allows this to happen.
3194 AUTH is initially labelled as a "nonmail command" so that one occurrence
3195 doesn't get counted. We change the label here so that multiple failing
3196 AUTHS will eventually hit the nonmail threshold. */
3200 authentication_failed = TRUE;
3201 cmd_list[CMD_LIST_AUTH].is_mail_cmd = FALSE;
3203 if (!auth_advertised && !allow_auth_unadvertised)
3205 done = synprot_error(L_smtp_protocol_error, 503, NULL,
3206 US"AUTH command used when not advertised");
3209 if (sender_host_authenticated != NULL)
3211 done = synprot_error(L_smtp_protocol_error, 503, NULL,
3212 US"already authenticated");
3215 if (sender_address != NULL)
3217 done = synprot_error(L_smtp_protocol_error, 503, NULL,
3218 US"not permitted in mail transaction");
3224 if (acl_smtp_auth != NULL)
3226 rc = acl_check(ACL_WHERE_AUTH, NULL, acl_smtp_auth, &user_msg, &log_msg);
3229 done = smtp_handle_acl_fail(ACL_WHERE_AUTH, rc, user_msg, log_msg);
3234 /* Find the name of the requested authentication mechanism. */
3237 while ((c = *smtp_cmd_data) != 0 && !isspace(c))
3239 if (!isalnum(c) && c != '-' && c != '_')
3241 done = synprot_error(L_smtp_syntax_error, 501, NULL,
3242 US"invalid character in authentication mechanism name");
3248 /* If not at the end of the line, we must be at white space. Terminate the
3249 name and move the pointer on to any data that may be present. */
3251 if (*smtp_cmd_data != 0)
3253 *smtp_cmd_data++ = 0;
3254 while (isspace(*smtp_cmd_data)) smtp_cmd_data++;
3257 /* Search for an authentication mechanism which is configured for use
3258 as a server and which has been advertised (unless, sigh, allow_auth_
3259 unadvertised is set). */
3261 for (au = auths; au != NULL; au = au->next)
3263 if (strcmpic(s, au->public_name) == 0 && au->server &&
3264 (au->advertised || allow_auth_unadvertised)) break;
3269 done = synprot_error(L_smtp_protocol_error, 504, NULL,
3270 string_sprintf("%s authentication mechanism not supported", s));
3274 /* Run the checking code, passing the remainder of the command line as
3275 data. Initials the $auth<n> variables as empty. Initialize $0 empty and set
3276 it as the only set numerical variable. The authenticator may set $auth<n>
3277 and also set other numeric variables. The $auth<n> variables are preferred
3278 nowadays; the numerical variables remain for backwards compatibility.
3280 Afterwards, have a go at expanding the set_id string, even if
3281 authentication failed - for bad passwords it can be useful to log the
3282 userid. On success, require set_id to expand and exist, and put it in
3283 authenticated_id. Save this in permanent store, as the working store gets
3284 reset at HELO, RSET, etc. */
3286 for (i = 0; i < AUTH_VARS; i++) auth_vars[i] = NULL;
3288 expand_nlength[0] = 0; /* $0 contains nothing */
3290 c = (au->info->servercode)(au, smtp_cmd_data);
3291 if (au->set_id != NULL) set_id = expand_string(au->set_id);
3292 expand_nmax = -1; /* Reset numeric variables */
3293 for (i = 0; i < AUTH_VARS; i++) auth_vars[i] = NULL; /* Reset $auth<n> */
3295 /* The value of authenticated_id is stored in the spool file and printed in
3296 log lines. It must not contain binary zeros or newline characters. In
3297 normal use, it never will, but when playing around or testing, this error
3298 can (did) happen. To guard against this, ensure that the id contains only
3299 printing characters. */
3301 if (set_id != NULL) set_id = string_printing(set_id);
3303 /* For the non-OK cases, set up additional logging data if set_id
3308 if (set_id != NULL && *set_id != 0)
3309 set_id = string_sprintf(" (set_id=%s)", set_id);
3313 /* Switch on the result */
3318 if (au->set_id == NULL || set_id != NULL) /* Complete success */
3320 if (set_id != NULL) authenticated_id = string_copy_malloc(set_id);
3321 sender_host_authenticated = au->name;
3322 authentication_failed = FALSE;
3323 authenticated_fail_id = NULL; /* Impossible to already be set? */
3326 (sender_host_address ? protocols : protocols_local)
3327 [pextend + pauthed + (tls_in.active >= 0 ? pcrpted:0)];
3328 s = ss = US"235 Authentication succeeded";
3329 authenticated_by = au;
3333 /* Authentication succeeded, but we failed to expand the set_id string.
3334 Treat this as a temporary error. */
3336 auth_defer_msg = expand_string_message;
3340 if (set_id != NULL) authenticated_fail_id = string_copy_malloc(set_id);
3341 s = string_sprintf("435 Unable to authenticate at present%s",
3342 auth_defer_user_msg);
3343 ss = string_sprintf("435 Unable to authenticate at present%s: %s",
3344 set_id, auth_defer_msg);
3348 s = ss = US"501 Invalid base64 data";
3352 s = ss = US"501 Authentication cancelled";
3356 s = ss = US"553 Initial data not expected";
3360 if (set_id != NULL) authenticated_fail_id = string_copy_malloc(set_id);
3361 s = US"535 Incorrect authentication data";
3362 ss = string_sprintf("535 Incorrect authentication data%s", set_id);
3366 if (set_id != NULL) authenticated_fail_id = string_copy_malloc(set_id);
3367 s = US"435 Internal error";
3368 ss = string_sprintf("435 Internal error%s: return %d from authentication "
3369 "check", set_id, c);
3373 smtp_printf("%s\r\n", s);
3375 log_write(0, LOG_MAIN|LOG_REJECT, "%s authenticator failed for %s: %s",
3376 au->name, host_and_ident(FALSE), ss);
3378 break; /* AUTH_CMD */
3380 /* The HELO/EHLO commands are permitted to appear in the middle of a
3381 session as well as at the beginning. They have the effect of a reset in
3382 addition to their other functions. Their absence at the start cannot be
3383 taken to be an error.
3387 If the EHLO command is not acceptable to the SMTP server, 501, 500,
3388 or 502 failure replies MUST be returned as appropriate. The SMTP
3389 server MUST stay in the same state after transmitting these replies
3390 that it was in before the EHLO was received.
3392 Therefore, we do not do the reset until after checking the command for
3393 acceptability. This change was made for Exim release 4.11. Previously
3394 it did the reset first. */
3407 HELO_EHLO: /* Common code for HELO and EHLO */
3408 cmd_list[CMD_LIST_HELO].is_mail_cmd = FALSE;
3409 cmd_list[CMD_LIST_EHLO].is_mail_cmd = FALSE;
3411 /* Reject the HELO if its argument was invalid or non-existent. A
3412 successful check causes the argument to be saved in malloc store. */
3414 if (!check_helo(smtp_cmd_data))
3416 smtp_printf("501 Syntactically invalid %s argument(s)\r\n", hello);
3418 log_write(0, LOG_MAIN|LOG_REJECT, "rejected %s from %s: syntactically "
3419 "invalid argument(s): %s", hello, host_and_ident(FALSE),
3420 (*smtp_cmd_argument == 0)? US"(no argument given)" :
3421 string_printing(smtp_cmd_argument));
3423 if (++synprot_error_count > smtp_max_synprot_errors)
3425 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
3426 "syntax or protocol errors (last command was \"%s\")",
3427 host_and_ident(FALSE), string_printing(smtp_cmd_buffer));
3434 /* If sender_host_unknown is true, we have got here via the -bs interface,
3435 not called from inetd. Otherwise, we are running an IP connection and the
3436 host address will be set. If the helo name is the primary name of this
3437 host and we haven't done a reverse lookup, force one now. If helo_required
3438 is set, ensure that the HELO name matches the actual host. If helo_verify
3439 is set, do the same check, but softly. */
3441 if (!sender_host_unknown)
3443 BOOL old_helo_verified = helo_verified;
3444 uschar *p = smtp_cmd_data;
3446 while (*p != 0 && !isspace(*p)) { *p = tolower(*p); p++; }
3449 /* Force a reverse lookup if HELO quoted something in helo_lookup_domains
3450 because otherwise the log can be confusing. */
3452 if (sender_host_name == NULL &&
3453 (deliver_domain = sender_helo_name, /* set $domain */
3454 match_isinlist(sender_helo_name, CUSS &helo_lookup_domains, 0,
3455 &domainlist_anchor, NULL, MCL_DOMAIN, TRUE, NULL)) == OK)
3456 (void)host_name_lookup();
3458 /* Rebuild the fullhost info to include the HELO name (and the real name
3459 if it was looked up.) */
3461 host_build_sender_fullhost(); /* Rebuild */
3462 set_process_info("handling%s incoming connection from %s",
3463 (tls_in.active >= 0)? " TLS" : "", host_and_ident(FALSE));
3465 /* Verify if configured. This doesn't give much security, but it does
3466 make some people happy to be able to do it. If helo_required is set,
3467 (host matches helo_verify_hosts) failure forces rejection. If helo_verify
3468 is set (host matches helo_try_verify_hosts), it does not. This is perhaps
3469 now obsolescent, since the verification can now be requested selectively
3472 helo_verified = helo_verify_failed = FALSE;
3473 if (helo_required || helo_verify)
3475 BOOL tempfail = !smtp_verify_helo();
3480 smtp_printf("%d %s argument does not match calling host\r\n",
3481 tempfail? 451 : 550, hello);
3482 log_write(0, LOG_MAIN|LOG_REJECT, "%srejected \"%s %s\" from %s",
3483 tempfail? "temporarily " : "",
3484 hello, sender_helo_name, host_and_ident(FALSE));
3485 helo_verified = old_helo_verified;
3486 break; /* End of HELO/EHLO processing */
3488 HDEBUG(D_all) debug_printf("%s verification failed but host is in "
3489 "helo_try_verify_hosts\n", hello);
3494 #ifdef EXPERIMENTAL_SPF
3495 /* set up SPF context */
3496 spf_init(sender_helo_name, sender_host_address);
3499 /* Apply an ACL check if one is defined; afterwards, recheck
3500 synchronization in case the client started sending in a delay. */
3502 if (acl_smtp_helo != NULL)
3504 rc = acl_check(ACL_WHERE_HELO, NULL, acl_smtp_helo, &user_msg, &log_msg);
3507 done = smtp_handle_acl_fail(ACL_WHERE_HELO, rc, user_msg, log_msg);
3508 sender_helo_name = NULL;
3509 host_build_sender_fullhost(); /* Rebuild */
3512 else if (!check_sync()) goto SYNC_FAILURE;
3515 /* Generate an OK reply. The default string includes the ident if present,
3516 and also the IP address if present. Reflecting back the ident is intended
3517 as a deterrent to mail forgers. For maximum efficiency, and also because
3518 some broken systems expect each response to be in a single packet, arrange
3519 that the entire reply is sent in one write(). */
3521 auth_advertised = FALSE;
3522 pipelining_advertised = FALSE;
3524 tls_advertised = FALSE;
3526 dsn_advertised = FALSE;
3527 #ifdef EXPERIMENTAL_INTERNATIONAL
3528 smtputf8_advertised = FALSE;
3531 smtp_code = US"250 "; /* Default response code plus space*/
3532 if (user_msg == NULL)
3534 s = string_sprintf("%.3s %s Hello %s%s%s",
3536 smtp_active_hostname,
3537 (sender_ident == NULL)? US"" : sender_ident,
3538 (sender_ident == NULL)? US"" : US" at ",
3539 (sender_host_name == NULL)? sender_helo_name : sender_host_name);
3544 if (sender_host_address != NULL)
3546 s = string_cat(s, &size, &ptr, US" [", 2);
3547 s = string_cat(s, &size, &ptr, sender_host_address,
3548 Ustrlen(sender_host_address));
3549 s = string_cat(s, &size, &ptr, US"]", 1);
3553 /* A user-supplied EHLO greeting may not contain more than one line. Note
3554 that the code returned by smtp_message_code() includes the terminating
3555 whitespace character. */
3561 smtp_message_code(&smtp_code, &codelen, &user_msg, NULL);
3562 s = string_sprintf("%.*s%s", codelen, smtp_code, user_msg);
3563 if ((ss = strpbrk(CS s, "\r\n")) != NULL)
3565 log_write(0, LOG_MAIN|LOG_PANIC, "EHLO/HELO response must not contain "
3566 "newlines: message truncated: %s", string_printing(s));
3573 s = string_cat(s, &size, &ptr, US"\r\n", 2);
3575 /* If we received EHLO, we must create a multiline response which includes
3576 the functions supported. */
3582 /* I'm not entirely happy with this, as an MTA is supposed to check
3583 that it has enough room to accept a message of maximum size before
3584 it sends this. However, there seems little point in not sending it.
3585 The actual size check happens later at MAIL FROM time. By postponing it
3586 till then, VRFY and EXPN can be used after EHLO when space is short. */
3588 if (thismessage_size_limit > 0)
3590 sprintf(CS big_buffer, "%.3s-SIZE %d\r\n", smtp_code,
3591 thismessage_size_limit);
3592 s = string_cat(s, &size, &ptr, big_buffer, Ustrlen(big_buffer));
3596 s = string_cat(s, &size, &ptr, smtp_code, 3);
3597 s = string_cat(s, &size, &ptr, US"-SIZE\r\n", 7);
3600 /* Exim does not do protocol conversion or data conversion. It is 8-bit
3601 clean; if it has an 8-bit character in its hand, it just sends it. It
3602 cannot therefore specify 8BITMIME and remain consistent with the RFCs.
3603 However, some users want this option simply in order to stop MUAs
3604 mangling messages that contain top-bit-set characters. It is therefore
3605 provided as an option. */
3607 if (accept_8bitmime)
3609 s = string_cat(s, &size, &ptr, smtp_code, 3);
3610 s = string_cat(s, &size, &ptr, US"-8BITMIME\r\n", 11);
3613 /* Advertise DSN support if configured to do so. */
3614 if (verify_check_host(&dsn_advertise_hosts) != FAIL)
3616 s = string_cat(s, &size, &ptr, smtp_code, 3);
3617 s = string_cat(s, &size, &ptr, US"-DSN\r\n", 6);
3618 dsn_advertised = TRUE;
3621 /* Advertise ETRN if there's an ACL checking whether a host is
3622 permitted to issue it; a check is made when any host actually tries. */
3624 if (acl_smtp_etrn != NULL)
3626 s = string_cat(s, &size, &ptr, smtp_code, 3);
3627 s = string_cat(s, &size, &ptr, US"-ETRN\r\n", 7);
3630 /* Advertise EXPN if there's an ACL checking whether a host is
3631 permitted to issue it; a check is made when any host actually tries. */
3633 if (acl_smtp_expn != NULL)
3635 s = string_cat(s, &size, &ptr, smtp_code, 3);
3636 s = string_cat(s, &size, &ptr, US"-EXPN\r\n", 7);
3639 /* Exim is quite happy with pipelining, so let the other end know that
3640 it is safe to use it, unless advertising is disabled. */
3642 if (pipelining_enable &&
3643 verify_check_host(&pipelining_advertise_hosts) == OK)
3645 s = string_cat(s, &size, &ptr, smtp_code, 3);
3646 s = string_cat(s, &size, &ptr, US"-PIPELINING\r\n", 13);
3647 sync_cmd_limit = NON_SYNC_CMD_PIPELINING;
3648 pipelining_advertised = TRUE;
3652 /* If any server authentication mechanisms are configured, advertise
3653 them if the current host is in auth_advertise_hosts. The problem with
3654 advertising always is that some clients then require users to
3655 authenticate (and aren't configurable otherwise) even though it may not
3656 be necessary (e.g. if the host is in host_accept_relay).
3658 RFC 2222 states that SASL mechanism names contain only upper case
3659 letters, so output the names in upper case, though we actually recognize
3660 them in either case in the AUTH command. */
3664 if (verify_check_host(&auth_advertise_hosts) == OK)
3668 for (au = auths; au != NULL; au = au->next)
3670 if (au->server && (au->advertise_condition == NULL ||
3671 expand_check_condition(au->advertise_condition, au->name,
3672 US"authenticator")))
3677 s = string_cat(s, &size, &ptr, smtp_code, 3);
3678 s = string_cat(s, &size, &ptr, US"-AUTH", 5);
3680 auth_advertised = TRUE;
3683 s = string_cat(s, &size, &ptr, US" ", 1);
3684 s = string_cat(s, &size, &ptr, au->public_name,
3685 Ustrlen(au->public_name));
3686 while (++saveptr < ptr) s[saveptr] = toupper(s[saveptr]);
3687 au->advertised = TRUE;
3689 else au->advertised = FALSE;
3691 if (!first) s = string_cat(s, &size, &ptr, US"\r\n", 2);
3695 /* Advertise TLS (Transport Level Security) aka SSL (Secure Socket Layer)
3696 if it has been included in the binary, and the host matches
3697 tls_advertise_hosts. We must *not* advertise if we are already in a
3698 secure connection. */
3701 if (tls_in.active < 0 &&
3702 verify_check_host(&tls_advertise_hosts) != FAIL)
3704 s = string_cat(s, &size, &ptr, smtp_code, 3);
3705 s = string_cat(s, &size, &ptr, US"-STARTTLS\r\n", 11);
3706 tls_advertised = TRUE;
3710 #ifndef DISABLE_PRDR
3711 /* Per Recipient Data Response, draft by Eric A. Hall extending RFC */
3714 s = string_cat(s, &size, &ptr, smtp_code, 3);
3715 s = string_cat(s, &size, &ptr, US"-PRDR\r\n", 7);
3719 #ifdef EXPERIMENTAL_INTERNATIONAL
3720 if ( accept_8bitmime
3721 && verify_check_host(&smtputf8_advertise_hosts) != FAIL)
3723 s = string_cat(s, &size, &ptr, smtp_code, 3);
3724 s = string_cat(s, &size, &ptr, US"-SMTPUTF8\r\n", 11);
3725 smtputf8_advertised = TRUE;
3729 /* Finish off the multiline reply with one that is always available. */
3731 s = string_cat(s, &size, &ptr, smtp_code, 3);
3732 s = string_cat(s, &size, &ptr, US" HELP\r\n", 7);
3735 /* Terminate the string (for debug), write it, and note that HELO/EHLO
3741 if (tls_in.active >= 0) (void)tls_write(TRUE, s, ptr); else
3745 int i = fwrite(s, 1, ptr, smtp_out); i = i; /* compiler quietening */
3750 while ((cr = Ustrchr(s, '\r')) != NULL) /* lose CRs */
3751 memmove(cr, cr + 1, (ptr--) - (cr - s));
3752 debug_printf("SMTP>> %s", s);
3756 /* Reset the protocol and the state, abandoning any previous message. */
3758 (sender_host_address ? protocols : protocols_local)
3760 ? pextend + (sender_host_authenticated ? pauthed : 0)
3762 + (tls_in.active >= 0 ? pcrpted : 0)
3764 smtp_reset(reset_point);
3766 break; /* HELO/EHLO */
3769 /* The MAIL command requires an address as an operand. All we do
3770 here is to parse it for syntactic correctness. The form "<>" is
3771 a special case which converts into an empty string. The start/end
3772 pointers in the original are not used further for this address, as
3773 it is the canonical extracted address which is all that is kept. */
3777 smtp_mailcmd_count++; /* Count for limit and ratelimit */
3778 was_rej_mail = TRUE; /* Reset if accepted */
3779 env_mail_type_t * mail_args; /* Sanity check & validate args */
3781 if (helo_required && !helo_seen)
3783 smtp_printf("503 HELO or EHLO required\r\n");
3784 log_write(0, LOG_MAIN|LOG_REJECT, "rejected MAIL from %s: no "
3785 "HELO/EHLO given", host_and_ident(FALSE));
3789 if (sender_address != NULL)
3791 done = synprot_error(L_smtp_protocol_error, 503, NULL,
3792 US"sender already given");
3796 if (smtp_cmd_data[0] == 0)
3798 done = synprot_error(L_smtp_protocol_error, 501, NULL,
3799 US"MAIL must have an address operand");
3803 /* Check to see if the limit for messages per connection would be
3804 exceeded by accepting further messages. */
3806 if (smtp_accept_max_per_connection > 0 &&
3807 smtp_mailcmd_count > smtp_accept_max_per_connection)
3809 smtp_printf("421 too many messages in this connection\r\n");
3810 log_write(0, LOG_MAIN|LOG_REJECT, "rejected MAIL command %s: too many "
3811 "messages in one connection", host_and_ident(TRUE));
3815 /* Reset for start of message - even if this is going to fail, we
3816 obviously need to throw away any previous data. */
3818 smtp_reset(reset_point);
3820 sender_data = recipient_data = NULL;
3822 /* Loop, checking for ESMTP additions to the MAIL FROM command. */
3826 uschar *name, *value, *end;
3827 unsigned long int size;
3828 BOOL arg_error = FALSE;
3830 if (!extract_option(&name, &value)) break;
3832 for (mail_args = env_mail_type_list;
3833 (char *)mail_args < (char *)env_mail_type_list + sizeof(env_mail_type_list);
3836 if (strcmpic(name, mail_args->name) == 0)
3838 if (mail_args->need_value && strcmpic(value, US"") == 0)
3841 switch(mail_args->value)
3843 /* Handle SIZE= by reading the value. We don't do the check till later,
3844 in order to be able to log the sender address on failure. */
3845 case ENV_MAIL_OPT_SIZE:
3846 if (((size = Ustrtoul(value, &end, 10)), *end == 0))
3848 if ((size == ULONG_MAX && errno == ERANGE) || size > INT_MAX)
3850 message_size = (int)size;
3856 /* If this session was initiated with EHLO and accept_8bitmime is set,
3857 Exim will have indicated that it supports the BODY=8BITMIME option. In
3858 fact, it does not support this according to the RFCs, in that it does not
3859 take any special action for forwarding messages containing 8-bit
3860 characters. That is why accept_8bitmime is not the default setting, but
3861 some sites want the action that is provided. We recognize both "8BITMIME"
3862 and "7BIT" as body types, but take no action. */
3863 case ENV_MAIL_OPT_BODY:
3864 if (accept_8bitmime) {
3865 if (strcmpic(value, US"8BITMIME") == 0)
3867 else if (strcmpic(value, US"7BIT") == 0)
3872 done = synprot_error(L_smtp_syntax_error, 501, NULL,
3873 US"invalid data for BODY");
3876 DEBUG(D_receive) debug_printf("8BITMIME: %d\n", body_8bitmime);
3882 /* Handle the two DSN options, but only if configured to do so (which
3883 will have caused "DSN" to be given in the EHLO response). The code itself
3884 is included only if configured in at build time. */
3886 case ENV_MAIL_OPT_RET:
3889 /* Check if RET has already been set */
3892 synprot_error(L_smtp_syntax_error, 501, NULL,
3893 US"RET can be specified once only");
3896 dsn_ret = strcmpic(value, US"HDRS") == 0
3898 : strcmpic(value, US"FULL") == 0
3901 DEBUG(D_receive) debug_printf("DSN_RET: %d\n", dsn_ret);
3902 /* Check for invalid invalid value, and exit with error */
3905 synprot_error(L_smtp_syntax_error, 501, NULL,
3906 US"Value for RET is invalid");
3911 case ENV_MAIL_OPT_ENVID:
3914 /* Check if the dsn envid has been already set */
3915 if (dsn_envid != NULL)
3917 synprot_error(L_smtp_syntax_error, 501, NULL,
3918 US"ENVID can be specified once only");
3921 dsn_envid = string_copy(value);
3922 DEBUG(D_receive) debug_printf("DSN_ENVID: %s\n", dsn_envid);
3926 /* Handle the AUTH extension. If the value given is not "<>" and either
3927 the ACL says "yes" or there is no ACL but the sending host is
3928 authenticated, we set it up as the authenticated sender. However, if the
3929 authenticator set a condition to be tested, we ignore AUTH on MAIL unless
3930 the condition is met. The value of AUTH is an xtext, which means that +,
3931 = and cntrl chars are coded in hex; however "<>" is unaffected by this
3933 case ENV_MAIL_OPT_AUTH:
3934 if (Ustrcmp(value, "<>") != 0)
3939 if (auth_xtextdecode(value, &authenticated_sender) < 0)
3941 /* Put back terminator overrides for error message */
3944 done = synprot_error(L_smtp_syntax_error, 501, NULL,
3945 US"invalid data for AUTH");
3948 if (acl_smtp_mailauth == NULL)
3950 ignore_msg = US"client not authenticated";
3951 rc = (sender_host_authenticated != NULL)? OK : FAIL;
3955 ignore_msg = US"rejected by ACL";
3956 rc = acl_check(ACL_WHERE_MAILAUTH, NULL, acl_smtp_mailauth,
3957 &user_msg, &log_msg);
3963 if (authenticated_by == NULL ||
3964 authenticated_by->mail_auth_condition == NULL ||
3965 expand_check_condition(authenticated_by->mail_auth_condition,
3966 authenticated_by->name, US"authenticator"))
3967 break; /* Accept the AUTH */
3969 ignore_msg = US"server_mail_auth_condition failed";
3970 if (authenticated_id != NULL)
3971 ignore_msg = string_sprintf("%s: authenticated ID=\"%s\"",
3972 ignore_msg, authenticated_id);
3977 authenticated_sender = NULL;
3978 log_write(0, LOG_MAIN, "ignoring AUTH=%s from %s (%s)",
3979 value, host_and_ident(TRUE), ignore_msg);
3982 /* Should only get DEFER or ERROR here. Put back terminator
3983 overrides for error message */
3988 (void)smtp_handle_acl_fail(ACL_WHERE_MAILAUTH, rc, user_msg,
3995 #ifndef DISABLE_PRDR
3996 case ENV_MAIL_OPT_PRDR:
3998 prdr_requested = TRUE;
4002 #ifdef EXPERIMENTAL_INTERNATIONAL
4003 case ENV_MAIL_OPT_UTF8:
4004 if (smtputf8_advertised)
4006 DEBUG(D_receive) debug_printf("smtputf8 requested\n");
4007 message_smtputf8 = allow_utf8_domains = TRUE;
4008 received_protocol = string_sprintf("utf8%s", received_protocol);
4012 /* Unknown option. Stick back the terminator characters and break
4013 the loop. Do the name-terminator second as extract_option sets
4014 value==name when it found no equal-sign.
4015 An error for a malformed address will occur. */
4022 /* Break out of for loop if switch() had bad argument or
4023 when start of the email address is reached */
4024 if (arg_error) break;
4027 /* If we have passed the threshold for rate limiting, apply the current
4028 delay, and update it for next time, provided this is a limited host. */
4030 if (smtp_mailcmd_count > smtp_rlm_threshold &&
4031 verify_check_host(&smtp_ratelimit_hosts) == OK)
4033 DEBUG(D_receive) debug_printf("rate limit MAIL: delay %.3g sec\n",
4034 smtp_delay_mail/1000.0);
4035 millisleep((int)smtp_delay_mail);
4036 smtp_delay_mail *= smtp_rlm_factor;
4037 if (smtp_delay_mail > (double)smtp_rlm_limit)
4038 smtp_delay_mail = (double)smtp_rlm_limit;
4041 /* Now extract the address, first applying any SMTP-time rewriting. The
4042 TRUE flag allows "<>" as a sender address. */
4044 raw_sender = rewrite_existflags & rewrite_smtp
4045 ? rewrite_one(smtp_cmd_data, rewrite_smtp, NULL, FALSE, US"",
4046 global_rewrite_rules)
4049 /* rfc821_domains = TRUE; << no longer needed */
4051 parse_extract_address(raw_sender, &errmess, &start, &end, &sender_domain,
4053 /* rfc821_domains = FALSE; << no longer needed */
4055 if (raw_sender == NULL)
4057 done = synprot_error(L_smtp_syntax_error, 501, smtp_cmd_data, errmess);
4061 sender_address = raw_sender;
4063 /* If there is a configured size limit for mail, check that this message
4064 doesn't exceed it. The check is postponed to this point so that the sender
4067 if (thismessage_size_limit > 0 && message_size > thismessage_size_limit)
4069 smtp_printf("552 Message size exceeds maximum permitted\r\n");
4070 log_write(L_size_reject,
4071 LOG_MAIN|LOG_REJECT, "rejected MAIL FROM:<%s> %s: "
4072 "message too big: size%s=%d max=%d",
4074 host_and_ident(TRUE),
4075 (message_size == INT_MAX)? ">" : "",
4077 thismessage_size_limit);
4078 sender_address = NULL;
4082 /* Check there is enough space on the disk unless configured not to.
4083 When smtp_check_spool_space is set, the check is for thismessage_size_limit
4084 plus the current message - i.e. we accept the message only if it won't
4085 reduce the space below the threshold. Add 5000 to the size to allow for
4086 overheads such as the Received: line and storing of recipients, etc.
4087 By putting the check here, even when SIZE is not given, it allow VRFY
4088 and EXPN etc. to be used when space is short. */
4090 if (!receive_check_fs(
4091 (smtp_check_spool_space && message_size >= 0)?
4092 message_size + 5000 : 0))
4094 smtp_printf("452 Space shortage, please try later\r\n");
4095 sender_address = NULL;
4099 /* If sender_address is unqualified, reject it, unless this is a locally
4100 generated message, or the sending host or net is permitted to send
4101 unqualified addresses - typically local machines behaving as MUAs -
4102 in which case just qualify the address. The flag is set above at the start
4103 of the SMTP connection. */
4105 if (sender_domain == 0 && sender_address[0] != 0)
4107 if (allow_unqualified_sender)
4109 sender_domain = Ustrlen(sender_address) + 1;
4110 sender_address = rewrite_address_qualify(sender_address, FALSE);
4111 DEBUG(D_receive) debug_printf("unqualified address %s accepted\n",
4116 smtp_printf("501 %s: sender address must contain a domain\r\n",
4118 log_write(L_smtp_syntax_error,
4119 LOG_MAIN|LOG_REJECT,
4120 "unqualified sender rejected: <%s> %s%s",
4122 host_and_ident(TRUE),
4124 sender_address = NULL;
4129 /* Apply an ACL check if one is defined, before responding. Afterwards,
4130 when pipelining is not advertised, do another sync check in case the ACL
4131 delayed and the client started sending in the meantime. */
4135 rc = acl_check(ACL_WHERE_MAIL, NULL, acl_smtp_mail, &user_msg, &log_msg);
4136 if (rc == OK && !pipelining_advertised && !check_sync())
4142 if (rc == OK || rc == DISCARD)
4145 smtp_printf("%s%s%s", US"250 OK",
4146 #ifndef DISABLE_PRDR
4147 prdr_requested ? US", PRDR Requested" : US"",
4154 #ifndef DISABLE_PRDR
4156 user_msg = string_sprintf("%s%s", user_msg, US", PRDR Requested");
4158 smtp_user_msg(US"250", user_msg);
4160 smtp_delay_rcpt = smtp_rlr_base;
4161 recipients_discarded = (rc == DISCARD);
4162 was_rej_mail = FALSE;
4166 done = smtp_handle_acl_fail(ACL_WHERE_MAIL, rc, user_msg, log_msg);
4167 sender_address = NULL;
4172 /* The RCPT command requires an address as an operand. There may be any
4173 number of RCPT commands, specifying multiple recipients. We build them all
4174 into a data structure. The start/end values given by parse_extract_address
4175 are not used, as we keep only the extracted address. */
4180 was_rcpt = rcpt_in_progress = TRUE;
4182 /* There must be a sender address; if the sender was rejected and
4183 pipelining was advertised, we assume the client was pipelining, and do not
4184 count this as a protocol error. Reset was_rej_mail so that further RCPTs
4185 get the same treatment. */
4187 if (sender_address == NULL)
4189 if (pipelining_advertised && last_was_rej_mail)
4191 smtp_printf("503 sender not yet given\r\n");
4192 was_rej_mail = TRUE;
4196 done = synprot_error(L_smtp_protocol_error, 503, NULL,
4197 US"sender not yet given");
4198 was_rcpt = FALSE; /* Not a valid RCPT */
4204 /* Check for an operand */
4206 if (smtp_cmd_data[0] == 0)
4208 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4209 US"RCPT must have an address operand");
4214 /* Set the DSN flags orcpt and dsn_flags from the session*/
4220 uschar *name, *value;
4222 if (!extract_option(&name, &value))
4225 if (dsn_advertised && strcmpic(name, US"ORCPT") == 0)
4227 /* Check whether orcpt has been already set */
4230 synprot_error(L_smtp_syntax_error, 501, NULL,
4231 US"ORCPT can be specified once only");
4234 orcpt = string_copy(value);
4235 DEBUG(D_receive) debug_printf("DSN orcpt: %s\n", orcpt);
4238 else if (dsn_advertised && strcmpic(name, US"NOTIFY") == 0)
4240 /* Check if the notify flags have been already set */
4243 synprot_error(L_smtp_syntax_error, 501, NULL,
4244 US"NOTIFY can be specified once only");
4247 if (strcmpic(value, US"NEVER") == 0)
4248 flags |= rf_notify_never;
4255 while (*pp != 0 && *pp != ',') pp++;
4256 if (*pp == ',') *pp++ = 0;
4257 if (strcmpic(p, US"SUCCESS") == 0)
4259 DEBUG(D_receive) debug_printf("DSN: Setting notify success\n");
4260 flags |= rf_notify_success;
4262 else if (strcmpic(p, US"FAILURE") == 0)
4264 DEBUG(D_receive) debug_printf("DSN: Setting notify failure\n");
4265 flags |= rf_notify_failure;
4267 else if (strcmpic(p, US"DELAY") == 0)
4269 DEBUG(D_receive) debug_printf("DSN: Setting notify delay\n");
4270 flags |= rf_notify_delay;
4274 /* Catch any strange values */
4275 synprot_error(L_smtp_syntax_error, 501, NULL,
4276 US"Invalid value for NOTIFY parameter");
4281 DEBUG(D_receive) debug_printf("DSN Flags: %x\n", flags);
4285 /* Unknown option. Stick back the terminator characters and break
4286 the loop. An error for a malformed address will occur. */
4290 DEBUG(D_receive) debug_printf("Invalid RCPT option: %s : %s\n", name, value);
4297 /* Apply SMTP rewriting then extract the working address. Don't allow "<>"
4298 as a recipient address */
4300 recipient = ((rewrite_existflags & rewrite_smtp) != 0)?
4301 rewrite_one(smtp_cmd_data, rewrite_smtp, NULL, FALSE, US"",
4302 global_rewrite_rules) : smtp_cmd_data;
4304 /* rfc821_domains = TRUE; << no longer needed */
4305 recipient = parse_extract_address(recipient, &errmess, &start, &end,
4306 &recipient_domain, FALSE);
4307 /* rfc821_domains = FALSE; << no longer needed */
4309 if (recipient == NULL)
4311 done = synprot_error(L_smtp_syntax_error, 501, smtp_cmd_data, errmess);
4316 /* If the recipient address is unqualified, reject it, unless this is a
4317 locally generated message. However, unqualified addresses are permitted
4318 from a configured list of hosts and nets - typically when behaving as
4319 MUAs rather than MTAs. Sad that SMTP is used for both types of traffic,
4320 really. The flag is set at the start of the SMTP connection.
4322 RFC 1123 talks about supporting "the reserved mailbox postmaster"; I always
4323 assumed this meant "reserved local part", but the revision of RFC 821 and
4324 friends now makes it absolutely clear that it means *mailbox*. Consequently
4325 we must always qualify this address, regardless. */
4327 if (recipient_domain == 0)
4329 if (allow_unqualified_recipient ||
4330 strcmpic(recipient, US"postmaster") == 0)
4332 DEBUG(D_receive) debug_printf("unqualified address %s accepted\n",
4334 recipient_domain = Ustrlen(recipient) + 1;
4335 recipient = rewrite_address_qualify(recipient, TRUE);
4340 smtp_printf("501 %s: recipient address must contain a domain\r\n",
4342 log_write(L_smtp_syntax_error,
4343 LOG_MAIN|LOG_REJECT, "unqualified recipient rejected: "
4344 "<%s> %s%s", recipient, host_and_ident(TRUE),
4350 /* Check maximum allowed */
4352 if (rcpt_count > recipients_max && recipients_max > 0)
4354 if (recipients_max_reject)
4357 smtp_printf("552 too many recipients\r\n");
4359 log_write(0, LOG_MAIN|LOG_REJECT, "too many recipients: message "
4360 "rejected: sender=<%s> %s", sender_address, host_and_ident(TRUE));
4365 smtp_printf("452 too many recipients\r\n");
4367 log_write(0, LOG_MAIN|LOG_REJECT, "too many recipients: excess "
4368 "temporarily rejected: sender=<%s> %s", sender_address,
4369 host_and_ident(TRUE));
4376 /* If we have passed the threshold for rate limiting, apply the current
4377 delay, and update it for next time, provided this is a limited host. */
4379 if (rcpt_count > smtp_rlr_threshold &&
4380 verify_check_host(&smtp_ratelimit_hosts) == OK)
4382 DEBUG(D_receive) debug_printf("rate limit RCPT: delay %.3g sec\n",
4383 smtp_delay_rcpt/1000.0);
4384 millisleep((int)smtp_delay_rcpt);
4385 smtp_delay_rcpt *= smtp_rlr_factor;
4386 if (smtp_delay_rcpt > (double)smtp_rlr_limit)
4387 smtp_delay_rcpt = (double)smtp_rlr_limit;
4390 /* If the MAIL ACL discarded all the recipients, we bypass ACL checking
4391 for them. Otherwise, check the access control list for this recipient. As
4392 there may be a delay in this, re-check for a synchronization error
4393 afterwards, unless pipelining was advertised. */
4395 if (recipients_discarded) rc = DISCARD; else
4397 rc = acl_check(ACL_WHERE_RCPT, recipient, acl_smtp_rcpt, &user_msg,
4399 if (rc == OK && !pipelining_advertised && !check_sync())
4403 /* The ACL was happy */
4407 if (user_msg == NULL) smtp_printf("250 Accepted\r\n");
4408 else smtp_user_msg(US"250", user_msg);
4409 receive_add_recipient(recipient, -1);
4411 /* Set the dsn flags in the recipients_list */
4412 recipients_list[recipients_count-1].orcpt = orcpt;
4413 recipients_list[recipients_count-1].dsn_flags = flags;
4415 DEBUG(D_receive) debug_printf("DSN: orcpt: %s flags: %d\n",
4416 recipients_list[recipients_count-1].orcpt,
4417 recipients_list[recipients_count-1].dsn_flags);
4420 /* The recipient was discarded */
4422 else if (rc == DISCARD)
4424 if (user_msg == NULL) smtp_printf("250 Accepted\r\n");
4425 else smtp_user_msg(US"250", user_msg);
4428 log_write(0, LOG_MAIN|LOG_REJECT, "%s F=<%s> rejected RCPT %s: "
4429 "discarded by %s ACL%s%s", host_and_ident(TRUE),
4430 (sender_address_unrewritten != NULL)?
4431 sender_address_unrewritten : sender_address,
4432 smtp_cmd_argument, recipients_discarded? "MAIL" : "RCPT",
4433 (log_msg == NULL)? US"" : US": ",
4434 (log_msg == NULL)? US"" : log_msg);
4437 /* Either the ACL failed the address, or it was deferred. */
4441 if (rc == FAIL) rcpt_fail_count++; else rcpt_defer_count++;
4442 done = smtp_handle_acl_fail(ACL_WHERE_RCPT, rc, user_msg, log_msg);
4447 /* The DATA command is legal only if it follows successful MAIL FROM
4448 and RCPT TO commands. However, if pipelining is advertised, a bad DATA is
4449 not counted as a protocol error if it follows RCPT (which must have been
4450 rejected if there are no recipients.) This function is complete when a
4451 valid DATA command is encountered.
4453 Note concerning the code used: RFC 2821 says this:
4455 - If there was no MAIL, or no RCPT, command, or all such commands
4456 were rejected, the server MAY return a "command out of sequence"
4457 (503) or "no valid recipients" (554) reply in response to the
4460 The example in the pipelining RFC 2920 uses 554, but I use 503 here
4461 because it is the same whether pipelining is in use or not.
4463 If all the RCPT commands that precede DATA provoked the same error message
4464 (often indicating some kind of system error), it is helpful to include it
4465 with the DATA rejection (an idea suggested by Tony Finch). */
4469 if (!discarded && recipients_count <= 0)
4471 if (rcpt_smtp_response_same && rcpt_smtp_response != NULL)
4473 uschar *code = US"503";
4474 int len = Ustrlen(rcpt_smtp_response);
4475 smtp_respond(code, 3, FALSE, US"All RCPT commands were rejected with "
4477 /* Responses from smtp_printf() will have \r\n on the end */
4478 if (len > 2 && rcpt_smtp_response[len-2] == '\r')
4479 rcpt_smtp_response[len-2] = 0;
4480 smtp_respond(code, 3, FALSE, rcpt_smtp_response);
4482 if (pipelining_advertised && last_was_rcpt)
4483 smtp_printf("503 Valid RCPT command must precede DATA\r\n");
4485 done = synprot_error(L_smtp_protocol_error, 503, NULL,
4486 US"valid RCPT command must precede DATA");
4490 if (toomany && recipients_max_reject)
4492 sender_address = NULL; /* This will allow a new MAIL without RSET */
4493 sender_address_unrewritten = NULL;
4494 smtp_printf("554 Too many recipients\r\n");
4498 /* If there is an ACL, re-check the synchronization afterwards, since the
4499 ACL may have delayed. To handle cutthrough delivery enforce a dummy call
4500 to get the DATA command sent. */
4502 if (acl_smtp_predata == NULL && cutthrough.fd < 0) rc = OK; else
4504 uschar * acl= acl_smtp_predata ? acl_smtp_predata : US"accept";
4505 enable_dollar_recipients = TRUE;
4506 rc = acl_check(ACL_WHERE_PREDATA, NULL, acl, &user_msg,
4508 enable_dollar_recipients = FALSE;
4509 if (rc == OK && !check_sync()) goto SYNC_FAILURE;
4516 if (user_msg == NULL)
4517 smtp_printf("%s Enter message, ending with \".\" on a line by itself\r\n", code);
4518 else smtp_user_msg(code, user_msg);
4520 message_ended = END_NOTENDED; /* Indicate in middle of data */
4523 /* Either the ACL failed the address, or it was deferred. */
4526 done = smtp_handle_acl_fail(ACL_WHERE_PREDATA, rc, user_msg, log_msg);
4532 rc = acl_check(ACL_WHERE_VRFY, NULL, acl_smtp_vrfy, &user_msg, &log_msg);
4534 done = smtp_handle_acl_fail(ACL_WHERE_VRFY, rc, user_msg, log_msg);
4540 /* rfc821_domains = TRUE; << no longer needed */
4541 address = parse_extract_address(smtp_cmd_data, &errmess, &start, &end,
4542 &recipient_domain, FALSE);
4543 /* rfc821_domains = FALSE; << no longer needed */
4545 if (address == NULL)
4546 s = string_sprintf("501 %s", errmess);
4549 address_item *addr = deliver_make_addr(address, FALSE);
4550 switch(verify_address(addr, NULL, vopt_is_recipient | vopt_qualify, -1,
4551 -1, -1, NULL, NULL, NULL))
4554 s = string_sprintf("250 <%s> is deliverable", address);
4558 s = (addr->user_message != NULL)?
4559 string_sprintf("451 <%s> %s", address, addr->user_message) :
4560 string_sprintf("451 Cannot resolve <%s> at this time", address);
4564 s = (addr->user_message != NULL)?
4565 string_sprintf("550 <%s> %s", address, addr->user_message) :
4566 string_sprintf("550 <%s> is not deliverable", address);
4567 log_write(0, LOG_MAIN, "VRFY failed for %s %s",
4568 smtp_cmd_argument, host_and_ident(TRUE));
4573 smtp_printf("%s\r\n", s);
4580 rc = acl_check(ACL_WHERE_EXPN, NULL, acl_smtp_expn, &user_msg, &log_msg);
4582 done = smtp_handle_acl_fail(ACL_WHERE_EXPN, rc, user_msg, log_msg);
4585 BOOL save_log_testing_mode = log_testing_mode;
4586 address_test_mode = log_testing_mode = TRUE;
4587 (void) verify_address(deliver_make_addr(smtp_cmd_data, FALSE),
4588 smtp_out, vopt_is_recipient | vopt_qualify | vopt_expn, -1, -1, -1,
4590 address_test_mode = FALSE;
4591 log_testing_mode = save_log_testing_mode; /* true for -bh */
4600 if (!tls_advertised)
4602 done = synprot_error(L_smtp_protocol_error, 503, NULL,
4603 US"STARTTLS command used when not advertised");
4607 /* Apply an ACL check if one is defined */
4609 if (acl_smtp_starttls != NULL)
4611 rc = acl_check(ACL_WHERE_STARTTLS, NULL, acl_smtp_starttls, &user_msg,
4615 done = smtp_handle_acl_fail(ACL_WHERE_STARTTLS, rc, user_msg, log_msg);
4620 /* RFC 2487 is not clear on when this command may be sent, though it
4621 does state that all information previously obtained from the client
4622 must be discarded if a TLS session is started. It seems reasonble to
4623 do an implied RSET when STARTTLS is received. */
4625 incomplete_transaction_log(US"STARTTLS");
4626 smtp_reset(reset_point);
4628 cmd_list[CMD_LIST_STARTTLS].is_mail_cmd = FALSE;
4630 /* There's an attack where more data is read in past the STARTTLS command
4631 before TLS is negotiated, then assumed to be part of the secure session
4632 when used afterwards; we use segregated input buffers, so are not
4633 vulnerable, but we want to note when it happens and, for sheer paranoia,
4634 ensure that the buffer is "wiped".
4635 Pipelining sync checks will normally have protected us too, unless disabled
4636 by configuration. */
4638 if (receive_smtp_buffered())
4641 debug_printf("Non-empty input buffer after STARTTLS; naive attack?");
4642 if (tls_in.active < 0)
4643 smtp_inend = smtp_inptr = smtp_inbuffer;
4644 /* and if TLS is already active, tls_server_start() should fail */
4647 /* There is nothing we value in the input buffer and if TLS is succesfully
4648 negotiated, we won't use this buffer again; if TLS fails, we'll just read
4649 fresh content into it. The buffer contains arbitrary content from an
4650 untrusted remote source; eg: NOOP <shellcode>\r\nSTARTTLS\r\n
4651 It seems safest to just wipe away the content rather than leave it as a
4652 target to jump to. */
4654 memset(smtp_inbuffer, 0, in_buffer_size);
4656 /* Attempt to start up a TLS session, and if successful, discard all
4657 knowledge that was obtained previously. At least, that's what the RFC says,
4658 and that's what happens by default. However, in order to work round YAEB,
4659 there is an option to remember the esmtp state. Sigh.
4661 We must allow for an extra EHLO command and an extra AUTH command after
4662 STARTTLS that don't add to the nonmail command count. */
4664 if ((rc = tls_server_start(tls_require_ciphers)) == OK)
4666 if (!tls_remember_esmtp)
4667 helo_seen = esmtp = auth_advertised = pipelining_advertised = FALSE;
4668 cmd_list[CMD_LIST_EHLO].is_mail_cmd = TRUE;
4669 cmd_list[CMD_LIST_AUTH].is_mail_cmd = TRUE;
4670 if (sender_helo_name != NULL)
4672 store_free(sender_helo_name);
4673 sender_helo_name = NULL;
4674 host_build_sender_fullhost(); /* Rebuild */
4675 set_process_info("handling incoming TLS connection from %s",
4676 host_and_ident(FALSE));
4679 (sender_host_address ? protocols : protocols_local)
4681 ? pextend + (sender_host_authenticated ? pauthed : 0)
4683 + (tls_in.active >= 0 ? pcrpted : 0)
4686 sender_host_authenticated = NULL;
4687 authenticated_id = NULL;
4688 sync_cmd_limit = NON_SYNC_CMD_NON_PIPELINING;
4689 DEBUG(D_tls) debug_printf("TLS active\n");
4690 break; /* Successful STARTTLS */
4693 /* Some local configuration problem was discovered before actually trying
4694 to do a TLS handshake; give a temporary error. */
4696 else if (rc == DEFER)
4698 smtp_printf("454 TLS currently unavailable\r\n");
4702 /* Hard failure. Reject everything except QUIT or closed connection. One
4703 cause for failure is a nested STARTTLS, in which case tls_in.active remains
4704 set, but we must still reject all incoming commands. */
4706 DEBUG(D_tls) debug_printf("TLS failed to start\n");
4709 switch(smtp_read_command(FALSE))
4712 log_write(L_smtp_connection, LOG_MAIN, "%s closed by EOF",
4713 smtp_get_connection_info());
4714 smtp_notquit_exit(US"tls-failed", NULL, NULL);
4718 /* It is perhaps arguable as to which exit ACL should be called here,
4719 but as it is probably a situation that almost never arises, it
4720 probably doesn't matter. We choose to call the real QUIT ACL, which in
4721 some sense is perhaps "right". */
4725 if (acl_smtp_quit != NULL)
4727 rc = acl_check(ACL_WHERE_QUIT, NULL, acl_smtp_quit, &user_msg,
4730 log_write(0, LOG_MAIN|LOG_PANIC, "ACL for QUIT returned ERROR: %s",
4733 if (user_msg == NULL)
4734 smtp_printf("221 %s closing connection\r\n", smtp_active_hostname);
4736 smtp_respond(US"221", 3, TRUE, user_msg);
4737 log_write(L_smtp_connection, LOG_MAIN, "%s closed by QUIT",
4738 smtp_get_connection_info());
4743 smtp_printf("554 Security failure\r\n");
4747 tls_close(TRUE, TRUE);
4752 /* The ACL for QUIT is provided for gathering statistical information or
4753 similar; it does not affect the response code, but it can supply a custom
4758 incomplete_transaction_log(US"QUIT");
4759 if (acl_smtp_quit != NULL)
4761 rc = acl_check(ACL_WHERE_QUIT, NULL, acl_smtp_quit, &user_msg, &log_msg);
4763 log_write(0, LOG_MAIN|LOG_PANIC, "ACL for QUIT returned ERROR: %s",
4766 if (user_msg == NULL)
4767 smtp_printf("221 %s closing connection\r\n", smtp_active_hostname);
4769 smtp_respond(US"221", 3, TRUE, user_msg);
4772 tls_close(TRUE, TRUE);
4776 log_write(L_smtp_connection, LOG_MAIN, "%s closed by QUIT",
4777 smtp_get_connection_info());
4783 incomplete_transaction_log(US"RSET");
4784 smtp_reset(reset_point);
4786 smtp_printf("250 Reset OK\r\n");
4787 cmd_list[CMD_LIST_RSET].is_mail_cmd = FALSE;
4793 smtp_printf("250 OK\r\n");
4797 /* Show ETRN/EXPN/VRFY if there's an ACL for checking hosts; if actually
4798 used, a check will be done for permitted hosts. Show STARTTLS only if not
4799 already in a TLS session and if it would be advertised in the EHLO
4804 smtp_printf("214-Commands supported:\r\n");
4808 Ustrcat(buffer, " AUTH");
4810 if (tls_in.active < 0 &&
4811 verify_check_host(&tls_advertise_hosts) != FAIL)
4812 Ustrcat(buffer, " STARTTLS");
4814 Ustrcat(buffer, " HELO EHLO MAIL RCPT DATA");
4815 Ustrcat(buffer, " NOOP QUIT RSET HELP");
4816 if (acl_smtp_etrn != NULL) Ustrcat(buffer, " ETRN");
4817 if (acl_smtp_expn != NULL) Ustrcat(buffer, " EXPN");
4818 if (acl_smtp_vrfy != NULL) Ustrcat(buffer, " VRFY");
4819 smtp_printf("214%s\r\n", buffer);
4825 incomplete_transaction_log(US"connection lost");
4826 smtp_notquit_exit(US"connection-lost", US"421",
4827 US"%s lost input connection", smtp_active_hostname);
4829 /* Don't log by default unless in the middle of a message, as some mailers
4830 just drop the call rather than sending QUIT, and it clutters up the logs.
4833 if (sender_address != NULL || recipients_count > 0)
4834 log_write(L_lost_incoming_connection,
4836 "unexpected %s while reading SMTP command from %s%s",
4837 sender_host_unknown? "EOF" : "disconnection",
4838 host_and_ident(FALSE), smtp_read_error);
4840 else log_write(L_smtp_connection, LOG_MAIN, "%s lost%s",
4841 smtp_get_connection_info(), smtp_read_error);
4849 if (sender_address != NULL)
4851 done = synprot_error(L_smtp_protocol_error, 503, NULL,
4852 US"ETRN is not permitted inside a transaction");
4856 log_write(L_etrn, LOG_MAIN, "ETRN %s received from %s", smtp_cmd_argument,
4857 host_and_ident(FALSE));
4859 rc = acl_check(ACL_WHERE_ETRN, NULL, acl_smtp_etrn, &user_msg, &log_msg);
4862 done = smtp_handle_acl_fail(ACL_WHERE_ETRN, rc, user_msg, log_msg);
4866 /* Compute the serialization key for this command. */
4868 etrn_serialize_key = string_sprintf("etrn-%s\n", smtp_cmd_data);
4870 /* If a command has been specified for running as a result of ETRN, we
4871 permit any argument to ETRN. If not, only the # standard form is permitted,
4872 since that is strictly the only kind of ETRN that can be implemented
4873 according to the RFC. */
4875 if (smtp_etrn_command != NULL)
4879 etrn_command = smtp_etrn_command;
4880 deliver_domain = smtp_cmd_data;
4881 rc = transport_set_up_command(&argv, smtp_etrn_command, TRUE, 0, NULL,
4882 US"ETRN processing", &error);
4883 deliver_domain = NULL;
4886 log_write(0, LOG_MAIN|LOG_PANIC, "failed to set up ETRN command: %s",
4888 smtp_printf("458 Internal failure\r\n");
4893 /* Else set up to call Exim with the -R option. */
4897 if (*smtp_cmd_data++ != '#')
4899 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4900 US"argument must begin with #");
4903 etrn_command = US"exim -R";
4904 argv = CUSS child_exec_exim(CEE_RETURN_ARGV, TRUE, NULL, TRUE, 2, US"-R",
4908 /* If we are host-testing, don't actually do anything. */
4914 debug_printf("ETRN command is: %s\n", etrn_command);
4915 debug_printf("ETRN command execution skipped\n");
4917 if (user_msg == NULL) smtp_printf("250 OK\r\n");
4918 else smtp_user_msg(US"250", user_msg);
4923 /* If ETRN queue runs are to be serialized, check the database to
4924 ensure one isn't already running. */
4926 if (smtp_etrn_serialize && !enq_start(etrn_serialize_key))
4928 smtp_printf("458 Already processing %s\r\n", smtp_cmd_data);
4932 /* Fork a child process and run the command. We don't want to have to
4933 wait for the process at any point, so set SIGCHLD to SIG_IGN before
4934 forking. It should be set that way anyway for external incoming SMTP,
4935 but we save and restore to be tidy. If serialization is required, we
4936 actually run the command in yet another process, so we can wait for it
4937 to complete and then remove the serialization lock. */
4939 oldsignal = signal(SIGCHLD, SIG_IGN);
4941 if ((pid = fork()) == 0)
4943 smtp_input = FALSE; /* This process is not associated with the */
4944 (void)fclose(smtp_in); /* SMTP call any more. */
4945 (void)fclose(smtp_out);
4947 signal(SIGCHLD, SIG_DFL); /* Want to catch child */
4949 /* If not serializing, do the exec right away. Otherwise, fork down
4950 into another process. */
4952 if (!smtp_etrn_serialize || (pid = fork()) == 0)
4954 DEBUG(D_exec) debug_print_argv(argv);
4955 exim_nullstd(); /* Ensure std{in,out,err} exist */
4956 execv(CS argv[0], (char *const *)argv);
4957 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "exec of \"%s\" (ETRN) failed: %s",
4958 etrn_command, strerror(errno));
4959 _exit(EXIT_FAILURE); /* paranoia */
4962 /* Obey this if smtp_serialize and the 2nd fork yielded non-zero. That
4963 is, we are in the first subprocess, after forking again. All we can do
4964 for a failing fork is to log it. Otherwise, wait for the 2nd process to
4965 complete, before removing the serialization. */
4968 log_write(0, LOG_MAIN|LOG_PANIC, "2nd fork for serialized ETRN "
4969 "failed: %s", strerror(errno));
4973 DEBUG(D_any) debug_printf("waiting for serialized ETRN process %d\n",
4975 (void)wait(&status);
4976 DEBUG(D_any) debug_printf("serialized ETRN process %d ended\n",
4980 enq_end(etrn_serialize_key);
4981 _exit(EXIT_SUCCESS);
4984 /* Back in the top level SMTP process. Check that we started a subprocess
4985 and restore the signal state. */
4989 log_write(0, LOG_MAIN|LOG_PANIC, "fork of process for ETRN failed: %s",
4991 smtp_printf("458 Unable to fork process\r\n");
4992 if (smtp_etrn_serialize) enq_end(etrn_serialize_key);
4996 if (user_msg == NULL) smtp_printf("250 OK\r\n");
4997 else smtp_user_msg(US"250", user_msg);
5000 signal(SIGCHLD, oldsignal);
5005 done = synprot_error(L_smtp_syntax_error, 501, NULL,
5006 US"unexpected argument data");
5010 /* This currently happens only for NULLs, but could be extended. */
5013 done = synprot_error(L_smtp_syntax_error, 0, NULL, /* Just logs */
5014 US"NULL character(s) present (shown as '?')");
5015 smtp_printf("501 NULL characters are not allowed in SMTP commands\r\n");
5021 if (smtp_inend >= smtp_inbuffer + in_buffer_size)
5022 smtp_inend = smtp_inbuffer + in_buffer_size - 1;
5023 c = smtp_inend - smtp_inptr;
5024 if (c > 150) c = 150;
5026 incomplete_transaction_log(US"sync failure");
5027 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP protocol synchronization error "
5028 "(next input sent too soon: pipelining was%s advertised): "
5029 "rejected \"%s\" %s next input=\"%s\"",
5030 pipelining_advertised? "" : " not",
5031 smtp_cmd_buffer, host_and_ident(TRUE),
5032 string_printing(smtp_inptr));
5033 smtp_notquit_exit(US"synchronization-error", US"554",
5034 US"SMTP synchronization error");
5035 done = 1; /* Pretend eof - drops connection */
5039 case TOO_MANY_NONMAIL_CMD:
5040 s = smtp_cmd_buffer;
5041 while (*s != 0 && !isspace(*s)) s++;
5042 incomplete_transaction_log(US"too many non-mail commands");
5043 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
5044 "nonmail commands (last was \"%.*s\")", host_and_ident(FALSE),
5045 (int)(s - smtp_cmd_buffer), smtp_cmd_buffer);
5046 smtp_notquit_exit(US"bad-commands", US"554", US"Too many nonmail commands");
5047 done = 1; /* Pretend eof - drops connection */
5050 #ifdef EXPERIMENTAL_PROXY
5051 case PROXY_FAIL_IGNORE_CMD:
5052 smtp_printf("503 Command refused, required Proxy negotiation failed\r\n");
5057 if (unknown_command_count++ >= smtp_max_unknown_commands)
5059 log_write(L_smtp_syntax_error, LOG_MAIN,
5060 "SMTP syntax error in \"%s\" %s %s",
5061 string_printing(smtp_cmd_buffer), host_and_ident(TRUE),
5062 US"unrecognized command");
5063 incomplete_transaction_log(US"unrecognized command");
5064 smtp_notquit_exit(US"bad-commands", US"500",
5065 US"Too many unrecognized commands");
5067 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
5068 "unrecognized commands (last was \"%s\")", host_and_ident(FALSE),
5069 string_printing(smtp_cmd_buffer));
5072 done = synprot_error(L_smtp_syntax_error, 500, NULL,
5073 US"unrecognized command");
5077 /* This label is used by goto's inside loops that want to break out to
5078 the end of the command-processing loop. */
5081 last_was_rej_mail = was_rej_mail; /* Remember some last commands for */
5082 last_was_rcpt = was_rcpt; /* protocol error handling */
5086 return done - 2; /* Convert yield values */
5091 /* End of smtp_in.c */