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;
125 static BOOL helo_required = FALSE;
126 static BOOL helo_verify = FALSE;
127 static BOOL helo_seen;
128 static BOOL helo_accept_junk;
129 static BOOL count_nonmail;
130 static BOOL pipelining_advertised;
131 static BOOL rcpt_smtp_response_same;
132 static BOOL rcpt_in_progress;
133 static int nonmail_command_count;
134 static BOOL smtp_exit_function_called = 0;
135 static int synprot_error_count;
136 static int unknown_command_count;
137 static int sync_cmd_limit;
138 static int smtp_write_error = 0;
140 static uschar *rcpt_smtp_response;
141 static uschar *smtp_data_buffer;
142 static uschar *smtp_cmd_data;
144 /* We need to know the position of RSET, HELO, EHLO, AUTH, and STARTTLS. Their
145 final fields of all except AUTH are forced TRUE at the start of a new message
146 setup, to allow one of each between messages that is not counted as a nonmail
147 command. (In fact, only one of HELO/EHLO is not counted.) Also, we have to
148 allow a new EHLO after starting up TLS.
150 AUTH is "falsely" labelled as a mail command initially, so that it doesn't get
151 counted. However, the flag is changed when AUTH is received, so that multiple
152 failing AUTHs will eventually hit the limit. After a successful AUTH, another
153 AUTH is already forbidden. After a TLS session is started, AUTH's flag is again
154 forced TRUE, to allow for the re-authentication that can happen at that point.
156 QUIT is also "falsely" labelled as a mail command so that it doesn't up the
157 count of non-mail commands and possibly provoke an error. */
159 static smtp_cmd_list cmd_list[] = {
160 { "rset", sizeof("rset")-1, RSET_CMD, FALSE, FALSE }, /* First */
161 { "helo", sizeof("helo")-1, HELO_CMD, TRUE, FALSE },
162 { "ehlo", sizeof("ehlo")-1, EHLO_CMD, TRUE, FALSE },
163 { "auth", sizeof("auth")-1, AUTH_CMD, TRUE, TRUE },
165 { "starttls", sizeof("starttls")-1, STARTTLS_CMD, FALSE, FALSE },
168 /* If you change anything above here, also fix the definitions below. */
170 { "mail from:", sizeof("mail from:")-1, MAIL_CMD, TRUE, TRUE },
171 { "rcpt to:", sizeof("rcpt to:")-1, RCPT_CMD, TRUE, TRUE },
172 { "data", sizeof("data")-1, DATA_CMD, FALSE, TRUE },
173 { "quit", sizeof("quit")-1, QUIT_CMD, FALSE, TRUE },
174 { "noop", sizeof("noop")-1, NOOP_CMD, TRUE, FALSE },
175 { "etrn", sizeof("etrn")-1, ETRN_CMD, TRUE, FALSE },
176 { "vrfy", sizeof("vrfy")-1, VRFY_CMD, TRUE, FALSE },
177 { "expn", sizeof("expn")-1, EXPN_CMD, TRUE, FALSE },
178 { "help", sizeof("help")-1, HELP_CMD, TRUE, FALSE }
181 static smtp_cmd_list *cmd_list_end =
182 cmd_list + sizeof(cmd_list)/sizeof(smtp_cmd_list);
184 #define CMD_LIST_RSET 0
185 #define CMD_LIST_HELO 1
186 #define CMD_LIST_EHLO 2
187 #define CMD_LIST_AUTH 3
188 #define CMD_LIST_STARTTLS 4
190 /* This list of names is used for performing the smtp_no_mail logging action.
191 It must be kept in step with the SCH_xxx enumerations. */
193 static uschar *smtp_names[] =
195 US"NONE", US"AUTH", US"DATA", US"EHLO", US"ETRN", US"EXPN", US"HELO",
196 US"HELP", US"MAIL", US"NOOP", US"QUIT", US"RCPT", US"RSET", US"STARTTLS",
199 static uschar *protocols[] = {
200 US"local-smtp", /* HELO */
201 US"local-smtps", /* The rare case EHLO->STARTTLS->HELO */
202 US"local-esmtp", /* EHLO */
203 US"local-esmtps", /* EHLO->STARTTLS->EHLO */
204 US"local-esmtpa", /* EHLO->AUTH */
205 US"local-esmtpsa" /* EHLO->STARTTLS->EHLO->AUTH */
210 #define pcrpted 1 /* added to pextend or pnormal */
211 #define pauthed 2 /* added to pextend */
212 #define pnlocal 6 /* offset to remove "local" */
214 /* Sanity check and validate optional args to MAIL FROM: envelope */
216 ENV_MAIL_OPT_SIZE, ENV_MAIL_OPT_BODY, ENV_MAIL_OPT_AUTH,
217 #ifdef EXPERIMENTAL_PRDR
223 uschar * name; /* option requested during MAIL cmd */
224 int value; /* enum type */
225 BOOL need_value; /* TRUE requires value (name=value pair format)
226 FALSE is a singleton */
228 static env_mail_type_t env_mail_type_list[] = {
229 { US"SIZE", ENV_MAIL_OPT_SIZE, TRUE },
230 { US"BODY", ENV_MAIL_OPT_BODY, TRUE },
231 { US"AUTH", ENV_MAIL_OPT_AUTH, TRUE },
232 #ifdef EXPERIMENTAL_PRDR
233 { US"PRDR", ENV_MAIL_OPT_PRDR, FALSE },
235 { US"NULL", ENV_MAIL_OPT_NULL, FALSE }
238 /* When reading SMTP from a remote host, we have to use our own versions of the
239 C input-reading functions, in order to be able to flush the SMTP output only
240 when about to read more data from the socket. This is the only way to get
241 optimal performance when the client is using pipelining. Flushing for every
242 command causes a separate packet and reply packet each time; saving all the
243 responses up (when pipelining) combines them into one packet and one response.
245 For simplicity, these functions are used for *all* SMTP input, not only when
246 receiving over a socket. However, after setting up a secure socket (SSL), input
247 is read via the OpenSSL library, and another set of functions is used instead
250 These functions are set in the receive_getc etc. variables and called with the
251 same interface as the C functions. However, since there can only ever be
252 one incoming SMTP call, we just use a single buffer and flags. There is no need
253 to implement a complicated private FILE-like structure.*/
255 static uschar *smtp_inbuffer;
256 static uschar *smtp_inptr;
257 static uschar *smtp_inend;
258 static int smtp_had_eof;
259 static int smtp_had_error;
262 /*************************************************
263 * SMTP version of getc() *
264 *************************************************/
266 /* This gets the next byte from the SMTP input buffer. If the buffer is empty,
267 it flushes the output, and refills the buffer, with a timeout. The signal
268 handler is set appropriately by the calling function. This function is not used
269 after a connection has negotated itself into an TLS/SSL state.
272 Returns: the next character or EOF
278 if (smtp_inptr >= smtp_inend)
282 if (smtp_receive_timeout > 0) alarm(smtp_receive_timeout);
283 rc = read(fileno(smtp_in), smtp_inbuffer, in_buffer_size);
288 /* Must put the error text in fixed store, because this might be during
289 header reading, where it releases unused store above the header. */
292 smtp_had_error = save_errno;
293 smtp_read_error = string_copy_malloc(
294 string_sprintf(" (error: %s)", strerror(save_errno)));
296 else smtp_had_eof = 1;
300 dkim_exim_verify_feed(smtp_inbuffer, rc);
302 smtp_inend = smtp_inbuffer + rc;
303 smtp_inptr = smtp_inbuffer;
305 return *smtp_inptr++;
310 /*************************************************
311 * SMTP version of ungetc() *
312 *************************************************/
314 /* Puts a character back in the input buffer. Only ever
320 Returns: the character
326 *(--smtp_inptr) = ch;
333 /*************************************************
334 * SMTP version of feof() *
335 *************************************************/
337 /* Tests for a previous EOF
340 Returns: non-zero if the eof flag is set
352 /*************************************************
353 * SMTP version of ferror() *
354 *************************************************/
356 /* Tests for a previous read error, and returns with errno
357 restored to what it was when the error was detected.
360 Returns: non-zero if the error flag is set
366 errno = smtp_had_error;
367 return smtp_had_error;
372 /*************************************************
373 * Test for characters in the SMTP buffer *
374 *************************************************/
376 /* Used at the end of a message
385 return smtp_inptr < smtp_inend;
390 /*************************************************
391 * Write formatted string to SMTP channel *
392 *************************************************/
394 /* This is a separate function so that we don't have to repeat everything for
395 TLS support or debugging. It is global so that the daemon and the
396 authentication functions can use it. It does not return any error indication,
397 because major problems such as dropped connections won't show up till an output
398 flush for non-TLS connections. The smtp_fflush() function is available for
399 checking that: for convenience, TLS output errors are remembered here so that
400 they are also picked up later by smtp_fflush().
404 ... optional arguments
410 smtp_printf(const char *format, ...)
414 va_start(ap, format);
415 smtp_vprintf(format, ap);
419 /* This is split off so that verify.c:respond_printf() can, in effect, call
420 smtp_printf(), bearing in mind that in C a vararg function can't directly
421 call another vararg function, only a function which accepts a va_list. */
424 smtp_vprintf(const char *format, va_list ap)
428 yield = string_vformat(big_buffer, big_buffer_size, format, ap);
432 void *reset_point = store_get(0);
433 uschar *msg_copy, *cr, *end;
434 msg_copy = string_copy(big_buffer);
435 end = msg_copy + Ustrlen(msg_copy);
436 while ((cr = Ustrchr(msg_copy, '\r')) != NULL) /* lose CRs */
437 memmove(cr, cr + 1, (end--) - cr);
438 debug_printf("SMTP>> %s", msg_copy);
439 store_reset(reset_point);
444 log_write(0, LOG_MAIN|LOG_PANIC, "string too large in smtp_printf()");
445 smtp_closedown(US"Unexpected error");
446 exim_exit(EXIT_FAILURE);
449 /* If this is the first output for a (non-batch) RCPT command, see if all RCPTs
450 have had the same. Note: this code is also present in smtp_respond(). It would
451 be tidier to have it only in one place, but when it was added, it was easier to
452 do it that way, so as not to have to mess with the code for the RCPT command,
453 which sometimes uses smtp_printf() and sometimes smtp_respond(). */
455 if (rcpt_in_progress)
457 if (rcpt_smtp_response == NULL)
458 rcpt_smtp_response = string_copy(big_buffer);
459 else if (rcpt_smtp_response_same &&
460 Ustrcmp(rcpt_smtp_response, big_buffer) != 0)
461 rcpt_smtp_response_same = FALSE;
462 rcpt_in_progress = FALSE;
465 /* Now write the string */
468 if (tls_in.active >= 0)
470 if (tls_write(TRUE, big_buffer, Ustrlen(big_buffer)) < 0)
471 smtp_write_error = -1;
476 if (fprintf(smtp_out, "%s", big_buffer) < 0) smtp_write_error = -1;
481 /*************************************************
482 * Flush SMTP out and check for error *
483 *************************************************/
485 /* This function isn't currently used within Exim (it detects errors when it
486 tries to read the next SMTP input), but is available for use in local_scan().
487 For non-TLS connections, it flushes the output and checks for errors. For
488 TLS-connections, it checks for a previously-detected TLS write error.
491 Returns: 0 for no error; -1 after an error
497 if (tls_in.active < 0 && fflush(smtp_out) != 0) smtp_write_error = -1;
498 return smtp_write_error;
503 /*************************************************
504 * SMTP command read timeout *
505 *************************************************/
507 /* Signal handler for timing out incoming SMTP commands. This attempts to
510 Argument: signal number (SIGALRM)
515 command_timeout_handler(int sig)
517 sig = sig; /* Keep picky compilers happy */
518 log_write(L_lost_incoming_connection,
519 LOG_MAIN, "SMTP command timeout on%s connection from %s",
520 (tls_in.active >= 0)? " TLS" : "",
521 host_and_ident(FALSE));
522 if (smtp_batched_input)
523 moan_smtp_batch(NULL, "421 SMTP command timeout"); /* Does not return */
524 smtp_notquit_exit(US"command-timeout", US"421",
525 US"%s: SMTP command timeout - closing connection", smtp_active_hostname);
526 exim_exit(EXIT_FAILURE);
531 /*************************************************
533 *************************************************/
535 /* Signal handler for handling SIGTERM. Again, try to finish tidily.
537 Argument: signal number (SIGTERM)
542 command_sigterm_handler(int sig)
544 sig = sig; /* Keep picky compilers happy */
545 log_write(0, LOG_MAIN, "%s closed after SIGTERM", smtp_get_connection_info());
546 if (smtp_batched_input)
547 moan_smtp_batch(NULL, "421 SIGTERM received"); /* Does not return */
548 smtp_notquit_exit(US"signal-exit", US"421",
549 US"%s: Service not available - closing connection", smtp_active_hostname);
550 exim_exit(EXIT_FAILURE);
556 #ifdef EXPERIMENTAL_PROXY
557 /*************************************************
558 * Restore socket timeout to previous value *
559 *************************************************/
560 /* If the previous value was successfully retrieved, restore
561 it before returning control to the non-proxy routines
563 Arguments: fd - File descriptor for input
564 get_ok - Successfully retrieved previous values
565 tvtmp - Time struct with previous values
566 vslen - Length of time struct
570 restore_socket_timeout(int fd, int get_ok, struct timeval tvtmp, socklen_t vslen)
573 setsockopt(fd, SOL_SOCKET, SO_RCVTIMEO, (char *)&tvtmp, vslen);
576 /*************************************************
577 * Check if host is required proxy host *
578 *************************************************/
579 /* The function determines if inbound host will be a regular smtp host
580 or if it is configured that it must use Proxy Protocol.
587 check_proxy_protocol_host()
590 /* Cannot configure local connection as a proxy inbound */
591 if (sender_host_address == NULL) return proxy_session;
593 rc = verify_check_this_host(&proxy_required_hosts, NULL, NULL,
594 sender_host_address, NULL);
598 debug_printf("Detected proxy protocol configured host\n");
599 proxy_session = TRUE;
601 return proxy_session;
605 /*************************************************
606 * Setup host for proxy protocol *
607 *************************************************/
608 /* The function configures the connection based on a header from the
609 inbound host to use Proxy Protocol. The specification is very exact
610 so exit with an error if do not find the exact required pieces. This
611 includes an incorrect number of spaces separating args.
618 setup_proxy_protocol_host()
631 struct { /* TCP/UDP over IPv4, len = 12 */
637 struct { /* TCP/UDP over IPv6, len = 36 */
638 uint8_t src_addr[16];
639 uint8_t dst_addr[16];
643 struct { /* AF_UNIX sockets, len = 216 */
644 uschar src_addr[108];
645 uschar dst_addr[108];
651 /* Temp variables used in PPv2 address:port parsing */
653 char tmpip[INET_ADDRSTRLEN];
654 struct sockaddr_in tmpaddr;
655 char tmpip6[INET6_ADDRSTRLEN];
656 struct sockaddr_in6 tmpaddr6;
660 const char v2sig[13] = "\x0D\x0A\x0D\x0A\x00\x0D\x0A\x51\x55\x49\x54\x0A\x02";
661 uschar *iptype; /* To display debug info */
664 struct timeval tvtmp;
666 vslen = sizeof(struct timeval);
668 fd = fileno(smtp_in);
670 /* Save current socket timeout values */
671 get_ok = getsockopt(fd, SOL_SOCKET, SO_RCVTIMEO, (char *)&tvtmp,
674 /* Proxy Protocol host must send header within a short time
675 (default 3 seconds) or it's considered invalid */
676 tv.tv_sec = PROXY_NEGOTIATION_TIMEOUT_SEC;
677 tv.tv_usec = PROXY_NEGOTIATION_TIMEOUT_USEC;
678 setsockopt(fd, SOL_SOCKET, SO_RCVTIMEO, (char *)&tv,
679 sizeof(struct timeval));
683 /* The inbound host was declared to be a Proxy Protocol host, so
684 don't do a PEEK into the data, actually slurp it up. */
685 ret = recv(fd, &hdr, sizeof(hdr), 0);
687 while (ret == -1 && errno == EINTR);
691 restore_socket_timeout(fd, get_ok, tvtmp, vslen);
692 return (errno == EAGAIN) ? 0 : ERRNO_PROXYFAIL;
696 memcmp(&hdr.v2, v2sig, 13) == 0)
698 DEBUG(D_receive) debug_printf("Detected PROXYv2 header\n");
699 size = 16 + hdr.v2.len;
702 DEBUG(D_receive) debug_printf("Truncated or too large PROXYv2 header\n");
707 case 0x01: /* PROXY command */
710 case 0x11: /* TCPv4 address type */
712 tmpaddr.sin_addr.s_addr = hdr.v2.addr.ip4.src_addr;
713 inet_ntop(AF_INET, &(tmpaddr.sin_addr), (char *)&tmpip, sizeof(tmpip));
714 if (!string_is_ip_address(US tmpip,NULL))
716 DEBUG(D_receive) debug_printf("Invalid %s source IP\n", iptype);
717 return ERRNO_PROXYFAIL;
719 proxy_host_address = sender_host_address;
720 sender_host_address = string_copy(US tmpip);
721 tmpport = ntohs(hdr.v2.addr.ip4.src_port);
722 proxy_host_port = sender_host_port;
723 sender_host_port = tmpport;
724 /* Save dest ip/port */
725 tmpaddr.sin_addr.s_addr = hdr.v2.addr.ip4.dst_addr;
726 inet_ntop(AF_INET, &(tmpaddr.sin_addr), (char *)&tmpip, sizeof(tmpip));
727 if (!string_is_ip_address(US tmpip,NULL))
729 DEBUG(D_receive) debug_printf("Invalid %s dest port\n", iptype);
730 return ERRNO_PROXYFAIL;
732 proxy_target_address = string_copy(US tmpip);
733 tmpport = ntohs(hdr.v2.addr.ip4.dst_port);
734 proxy_target_port = tmpport;
736 case 0x21: /* TCPv6 address type */
738 memmove(tmpaddr6.sin6_addr.s6_addr, hdr.v2.addr.ip6.src_addr, 16);
739 inet_ntop(AF_INET6, &(tmpaddr6.sin6_addr), (char *)&tmpip6, sizeof(tmpip6));
740 if (!string_is_ip_address(US tmpip6,NULL))
742 DEBUG(D_receive) debug_printf("Invalid %s source IP\n", iptype);
743 return ERRNO_PROXYFAIL;
745 proxy_host_address = sender_host_address;
746 sender_host_address = string_copy(US tmpip6);
747 tmpport = ntohs(hdr.v2.addr.ip6.src_port);
748 proxy_host_port = sender_host_port;
749 sender_host_port = tmpport;
750 /* Save dest ip/port */
751 memmove(tmpaddr6.sin6_addr.s6_addr, hdr.v2.addr.ip6.dst_addr, 16);
752 inet_ntop(AF_INET6, &(tmpaddr6.sin6_addr), (char *)&tmpip6, sizeof(tmpip6));
753 if (!string_is_ip_address(US tmpip6,NULL))
755 DEBUG(D_receive) debug_printf("Invalid %s dest port\n", iptype);
756 return ERRNO_PROXYFAIL;
758 proxy_target_address = string_copy(US tmpip6);
759 tmpport = ntohs(hdr.v2.addr.ip6.dst_port);
760 proxy_target_port = tmpport;
764 debug_printf("Unsupported PROXYv2 connection type: 0x%02x\n",
768 /* Unsupported protocol, keep local connection address */
770 case 0x00: /* LOCAL command */
771 /* Keep local connection address for LOCAL */
775 debug_printf("Unsupported PROXYv2 command: 0x%02x\n",
781 memcmp(hdr.v1.line, "PROXY", 5) == 0)
783 uschar *p = string_copy(hdr.v1.line);
784 uschar *end = memchr(p, '\r', ret - 1);
785 uschar *sp; /* Utility variables follow */
789 if (!end || end[1] != '\n')
791 DEBUG(D_receive) debug_printf("Partial or invalid PROXY header\n");
794 *end = '\0'; /* Terminate the string */
795 size = end + 2 - hdr.v1.line; /* Skip header + CRLF */
796 DEBUG(D_receive) debug_printf("Detected PROXYv1 header\n");
797 /* Step through the string looking for the required fields. Ensure
798 strict adherance to required formatting, exit for any error. */
800 if (!isspace(*(p++)))
802 DEBUG(D_receive) debug_printf("Missing space after PROXY command\n");
805 if (!Ustrncmp(p, CCS"TCP4", 4))
807 else if (!Ustrncmp(p,CCS"TCP6", 4))
809 else if (!Ustrncmp(p,CCS"UNKNOWN", 7))
811 iptype = US"Unknown";
816 DEBUG(D_receive) debug_printf("Invalid TCP type\n");
820 p += Ustrlen(iptype);
821 if (!isspace(*(p++)))
823 DEBUG(D_receive) debug_printf("Missing space after TCP4/6 command\n");
826 /* Find the end of the arg */
827 if ((sp = Ustrchr(p, ' ')) == NULL)
830 debug_printf("Did not find proxied src %s\n", iptype);
834 if(!string_is_ip_address(p,NULL))
837 debug_printf("Proxied src arg is not an %s address\n", iptype);
840 proxy_host_address = sender_host_address;
841 sender_host_address = p;
843 if ((sp = Ustrchr(p, ' ')) == NULL)
846 debug_printf("Did not find proxy dest %s\n", iptype);
850 if(!string_is_ip_address(p,NULL))
853 debug_printf("Proxy dest arg is not an %s address\n", iptype);
856 proxy_target_address = p;
858 if ((sp = Ustrchr(p, ' ')) == NULL)
860 DEBUG(D_receive) debug_printf("Did not find proxied src port\n");
864 tmp_port = strtol(CCS p,&endc,10);
865 if (*endc || tmp_port == 0)
868 debug_printf("Proxied src port '%s' not an integer\n", p);
871 proxy_host_port = sender_host_port;
872 sender_host_port = tmp_port;
874 if ((sp = Ustrchr(p, '\0')) == NULL)
876 DEBUG(D_receive) debug_printf("Did not find proxy dest port\n");
879 tmp_port = strtol(CCS p,&endc,10);
880 if (*endc || tmp_port == 0)
883 debug_printf("Proxy dest port '%s' not an integer\n", p);
886 proxy_target_port = tmp_port;
887 /* Already checked for /r /n above. Good V1 header received. */
893 DEBUG(D_receive) debug_printf("Invalid proxy protocol version negotiation\n");
898 restore_socket_timeout(fd, get_ok, tvtmp, vslen);
899 /* Don't flush any potential buffer contents. Any input should cause a
900 synchronization failure */
904 restore_socket_timeout(fd, get_ok, tvtmp, vslen);
906 debug_printf("Valid %s sender from Proxy Protocol header\n", iptype);
907 return proxy_session;
911 /*************************************************
912 * Read one command line *
913 *************************************************/
915 /* Strictly, SMTP commands coming over the net are supposed to end with CRLF.
916 There are sites that don't do this, and in any case internal SMTP probably
917 should check only for LF. Consequently, we check here for LF only. The line
918 ends up with [CR]LF removed from its end. If we get an overlong line, treat as
919 an unknown command. The command is read into the global smtp_cmd_buffer so that
920 it is available via $smtp_command.
922 The character reading routine sets up a timeout for each block actually read
923 from the input (which may contain more than one command). We set up a special
924 signal handler that closes down the session on a timeout. Control does not
928 check_sync if TRUE, check synchronization rules if global option is TRUE
930 Returns: a code identifying the command (enumerated above)
934 smtp_read_command(BOOL check_sync)
939 BOOL hadnull = FALSE;
941 os_non_restarting_signal(SIGALRM, command_timeout_handler);
943 while ((c = (receive_getc)()) != '\n' && c != EOF)
945 if (ptr >= smtp_cmd_buffer_size)
947 os_non_restarting_signal(SIGALRM, sigalrm_handler);
955 smtp_cmd_buffer[ptr++] = c;
958 receive_linecount++; /* For BSMTP errors */
959 os_non_restarting_signal(SIGALRM, sigalrm_handler);
961 /* If hit end of file, return pseudo EOF command. Whether we have a
962 part-line already read doesn't matter, since this is an error state. */
964 if (c == EOF) return EOF_CMD;
966 /* Remove any CR and white space at the end of the line, and terminate the
969 while (ptr > 0 && isspace(smtp_cmd_buffer[ptr-1])) ptr--;
970 smtp_cmd_buffer[ptr] = 0;
972 DEBUG(D_receive) debug_printf("SMTP<< %s\n", smtp_cmd_buffer);
974 /* NULLs are not allowed in SMTP commands */
976 if (hadnull) return BADCHAR_CMD;
978 /* Scan command list and return identity, having set the data pointer
979 to the start of the actual data characters. Check for SMTP synchronization
982 for (p = cmd_list; p < cmd_list_end; p++)
984 #ifdef EXPERIMENTAL_PROXY
985 /* Only allow QUIT command if Proxy Protocol parsing failed */
986 if (proxy_session && proxy_session_failed)
988 if (p->cmd != QUIT_CMD)
992 if (strncmpic(smtp_cmd_buffer, US p->name, p->len) == 0 &&
993 (smtp_cmd_buffer[p->len-1] == ':' || /* "mail from:" or "rcpt to:" */
994 smtp_cmd_buffer[p->len] == 0 ||
995 smtp_cmd_buffer[p->len] == ' '))
997 if (smtp_inptr < smtp_inend && /* Outstanding input */
998 p->cmd < sync_cmd_limit && /* Command should sync */
999 check_sync && /* Local flag set */
1000 smtp_enforce_sync && /* Global flag set */
1001 sender_host_address != NULL && /* Not local input */
1002 !sender_host_notsocket) /* Really is a socket */
1005 /* The variables $smtp_command and $smtp_command_argument point into the
1006 unmodified input buffer. A copy of the latter is taken for actual
1007 processing, so that it can be chopped up into separate parts if necessary,
1008 for example, when processing a MAIL command options such as SIZE that can
1009 follow the sender address. */
1011 smtp_cmd_argument = smtp_cmd_buffer + p->len;
1012 while (isspace(*smtp_cmd_argument)) smtp_cmd_argument++;
1013 Ustrcpy(smtp_data_buffer, smtp_cmd_argument);
1014 smtp_cmd_data = smtp_data_buffer;
1016 /* Count non-mail commands from those hosts that are controlled in this
1017 way. The default is all hosts. We don't waste effort checking the list
1018 until we get a non-mail command, but then cache the result to save checking
1019 again. If there's a DEFER while checking the host, assume it's in the list.
1021 Note that one instance of RSET, EHLO/HELO, and STARTTLS is allowed at the
1022 start of each incoming message by fiddling with the value in the table. */
1024 if (!p->is_mail_cmd)
1026 if (count_nonmail == TRUE_UNSET) count_nonmail =
1027 verify_check_host(&smtp_accept_max_nonmail_hosts) != FAIL;
1028 if (count_nonmail && ++nonmail_command_count > smtp_accept_max_nonmail)
1029 return TOO_MANY_NONMAIL_CMD;
1032 /* If there is data for a command that does not expect it, generate the
1035 return (p->has_arg || *smtp_cmd_data == 0)? p->cmd : BADARG_CMD;
1039 #ifdef EXPERIMENTAL_PROXY
1040 /* Only allow QUIT command if Proxy Protocol parsing failed */
1041 if (proxy_session && proxy_session_failed)
1042 return PROXY_FAIL_IGNORE_CMD;
1045 /* Enforce synchronization for unknown commands */
1047 if (smtp_inptr < smtp_inend && /* Outstanding input */
1048 check_sync && /* Local flag set */
1049 smtp_enforce_sync && /* Global flag set */
1050 sender_host_address != NULL && /* Not local input */
1051 !sender_host_notsocket) /* Really is a socket */
1059 /*************************************************
1060 * Recheck synchronization *
1061 *************************************************/
1063 /* Synchronization checks can never be perfect because a packet may be on its
1064 way but not arrived when the check is done. Such checks can in any case only be
1065 done when TLS is not in use. Normally, the checks happen when commands are
1066 read: Exim ensures that there is no more input in the input buffer. In normal
1067 cases, the response to the command will be fast, and there is no further check.
1069 However, for some commands an ACL is run, and that can include delays. In those
1070 cases, it is useful to do another check on the input just before sending the
1071 response. This also applies at the start of a connection. This function does
1072 that check by means of the select() function, as long as the facility is not
1073 disabled or inappropriate. A failure of select() is ignored.
1075 When there is unwanted input, we read it so that it appears in the log of the
1079 Returns: TRUE if all is well; FALSE if there is input pending
1087 struct timeval tzero;
1089 if (!smtp_enforce_sync || sender_host_address == NULL ||
1090 sender_host_notsocket || tls_in.active >= 0)
1093 fd = fileno(smtp_in);
1098 rc = select(fd + 1, (SELECT_ARG2_TYPE *)&fds, NULL, NULL, &tzero);
1100 if (rc <= 0) return TRUE; /* Not ready to read */
1102 if (rc < 0) return TRUE; /* End of file or error */
1105 rc = smtp_inend - smtp_inptr;
1106 if (rc > 150) rc = 150;
1113 /*************************************************
1114 * Forced closedown of call *
1115 *************************************************/
1117 /* This function is called from log.c when Exim is dying because of a serious
1118 disaster, and also from some other places. If an incoming non-batched SMTP
1119 channel is open, it swallows the rest of the incoming message if in the DATA
1120 phase, sends the reply string, and gives an error to all subsequent commands
1121 except QUIT. The existence of an SMTP call is detected by the non-NULLness of
1125 message SMTP reply string to send, excluding the code
1131 smtp_closedown(uschar *message)
1133 if (smtp_in == NULL || smtp_batched_input) return;
1134 receive_swallow_smtp();
1135 smtp_printf("421 %s\r\n", message);
1139 switch(smtp_read_command(FALSE))
1145 smtp_printf("221 %s closing connection\r\n", smtp_active_hostname);
1150 smtp_printf("250 Reset OK\r\n");
1154 smtp_printf("421 %s\r\n", message);
1163 /*************************************************
1164 * Set up connection info for logging *
1165 *************************************************/
1167 /* This function is called when logging information about an SMTP connection.
1168 It sets up appropriate source information, depending on the type of connection.
1169 If sender_fullhost is NULL, we are at a very early stage of the connection;
1170 just use the IP address.
1173 Returns: a string describing the connection
1177 smtp_get_connection_info(void)
1179 uschar *hostname = (sender_fullhost == NULL)?
1180 sender_host_address : sender_fullhost;
1183 return string_sprintf("SMTP connection from %s", hostname);
1185 if (sender_host_unknown || sender_host_notsocket)
1186 return string_sprintf("SMTP connection from %s", sender_ident);
1189 return string_sprintf("SMTP connection from %s (via inetd)", hostname);
1191 if ((log_extra_selector & LX_incoming_interface) != 0 &&
1192 interface_address != NULL)
1193 return string_sprintf("SMTP connection from %s I=[%s]:%d", hostname,
1194 interface_address, interface_port);
1196 return string_sprintf("SMTP connection from %s", hostname);
1202 /* Append TLS-related information to a log line
1205 s String under construction: allocated string to extend, or NULL
1206 sizep Pointer to current allocation size (update on return), or NULL
1207 ptrp Pointer to index for new entries in string (update on return), or NULL
1209 Returns: Allocated string or NULL
1212 s_tlslog(uschar * s, int * sizep, int * ptrp)
1214 int size = sizep ? *sizep : 0;
1215 int ptr = ptrp ? *ptrp : 0;
1217 if ((log_extra_selector & LX_tls_cipher) != 0 && tls_in.cipher != NULL)
1218 s = string_append(s, &size, &ptr, 2, US" X=", tls_in.cipher);
1219 if ((log_extra_selector & LX_tls_certificate_verified) != 0 &&
1220 tls_in.cipher != NULL)
1221 s = string_append(s, &size, &ptr, 2, US" CV=",
1222 tls_in.certificate_verified? "yes":"no");
1223 if ((log_extra_selector & LX_tls_peerdn) != 0 && tls_in.peerdn != NULL)
1224 s = string_append(s, &size, &ptr, 3, US" DN=\"",
1225 string_printing(tls_in.peerdn), US"\"");
1226 if ((log_extra_selector & LX_tls_sni) != 0 && tls_in.sni != NULL)
1227 s = string_append(s, &size, &ptr, 3, US" SNI=\"",
1228 string_printing(tls_in.sni), US"\"");
1233 if (sizep) *sizep = size;
1234 if (ptrp) *ptrp = ptr;
1240 /*************************************************
1241 * Log lack of MAIL if so configured *
1242 *************************************************/
1244 /* This function is called when an SMTP session ends. If the log selector
1245 smtp_no_mail is set, write a log line giving some details of what has happened
1246 in the SMTP session.
1253 smtp_log_no_mail(void)
1258 if (smtp_mailcmd_count > 0 || (log_extra_selector & LX_smtp_no_mail) == 0)
1264 if (sender_host_authenticated != NULL)
1266 s = string_append(s, &size, &ptr, 2, US" A=", sender_host_authenticated);
1267 if (authenticated_id != NULL)
1268 s = string_append(s, &size, &ptr, 2, US":", authenticated_id);
1272 s = s_tlslog(s, &size, &ptr);
1275 sep = (smtp_connection_had[SMTP_HBUFF_SIZE-1] != SCH_NONE)?
1276 US" C=..." : US" C=";
1277 for (i = smtp_ch_index; i < SMTP_HBUFF_SIZE; i++)
1279 if (smtp_connection_had[i] != SCH_NONE)
1281 s = string_append(s, &size, &ptr, 2, sep,
1282 smtp_names[smtp_connection_had[i]]);
1287 for (i = 0; i < smtp_ch_index; i++)
1289 s = string_append(s, &size, &ptr, 2, sep, smtp_names[smtp_connection_had[i]]);
1293 if (s != NULL) s[ptr] = 0; else s = US"";
1294 log_write(0, LOG_MAIN, "no MAIL in SMTP connection from %s D=%s%s",
1295 host_and_ident(FALSE),
1296 readconf_printtime(time(NULL) - smtp_connection_start), s);
1301 /*************************************************
1302 * Check HELO line and set sender_helo_name *
1303 *************************************************/
1305 /* Check the format of a HELO line. The data for HELO/EHLO is supposed to be
1306 the domain name of the sending host, or an ip literal in square brackets. The
1307 arrgument is placed in sender_helo_name, which is in malloc store, because it
1308 must persist over multiple incoming messages. If helo_accept_junk is set, this
1309 host is permitted to send any old junk (needed for some broken hosts).
1310 Otherwise, helo_allow_chars can be used for rogue characters in general
1311 (typically people want to let in underscores).
1314 s the data portion of the line (already past any white space)
1316 Returns: TRUE or FALSE
1320 check_helo(uschar *s)
1323 uschar *end = s + Ustrlen(s);
1324 BOOL yield = helo_accept_junk;
1326 /* Discard any previous helo name */
1328 if (sender_helo_name != NULL)
1330 store_free(sender_helo_name);
1331 sender_helo_name = NULL;
1334 /* Skip tests if junk is permitted. */
1338 /* Allow the new standard form for IPv6 address literals, namely,
1339 [IPv6:....], and because someone is bound to use it, allow an equivalent
1340 IPv4 form. Allow plain addresses as well. */
1347 if (strncmpic(s, US"[IPv6:", 6) == 0)
1348 yield = (string_is_ip_address(s+6, NULL) == 6);
1349 else if (strncmpic(s, US"[IPv4:", 6) == 0)
1350 yield = (string_is_ip_address(s+6, NULL) == 4);
1352 yield = (string_is_ip_address(s+1, NULL) != 0);
1357 /* Non-literals must be alpha, dot, hyphen, plus any non-valid chars
1358 that have been configured (usually underscore - sigh). */
1365 if (!isalnum(*s) && *s != '.' && *s != '-' &&
1366 Ustrchr(helo_allow_chars, *s) == NULL)
1376 /* Save argument if OK */
1378 if (yield) sender_helo_name = string_copy_malloc(start);
1386 /*************************************************
1387 * Extract SMTP command option *
1388 *************************************************/
1390 /* This function picks the next option setting off the end of smtp_cmd_data. It
1391 is called for MAIL FROM and RCPT TO commands, to pick off the optional ESMTP
1392 things that can appear there.
1395 name point this at the name
1396 value point this at the data string
1398 Returns: TRUE if found an option
1402 extract_option(uschar **name, uschar **value)
1405 uschar *v = smtp_cmd_data + Ustrlen(smtp_cmd_data) - 1;
1406 while (isspace(*v)) v--;
1408 while (v > smtp_cmd_data && *v != '=' && !isspace(*v)) v--;
1413 while(isalpha(n[-1])) n--;
1414 /* RFC says SP, but TAB seen in wild and other major MTAs accept it */
1415 if (!isspace(n[-1])) return FALSE;
1421 if (v == smtp_cmd_data) return FALSE;
1433 /*************************************************
1434 * Reset for new message *
1435 *************************************************/
1437 /* This function is called whenever the SMTP session is reset from
1438 within either of the setup functions.
1440 Argument: the stacking pool storage reset point
1445 smtp_reset(void *reset_point)
1447 store_reset(reset_point);
1448 recipients_list = NULL;
1449 rcpt_count = rcpt_defer_count = rcpt_fail_count =
1450 raw_recipients_count = recipients_count = recipients_list_max = 0;
1451 cancel_cutthrough_connection("smtp reset");
1452 message_linecount = 0;
1454 acl_added_headers = NULL;
1455 acl_removed_headers = NULL;
1456 queue_only_policy = FALSE;
1457 rcpt_smtp_response = NULL;
1458 rcpt_smtp_response_same = TRUE;
1459 rcpt_in_progress = FALSE;
1460 deliver_freeze = FALSE; /* Can be set by ACL */
1461 freeze_tell = freeze_tell_config; /* Can be set by ACL */
1462 fake_response = OK; /* Can be set by ACL */
1463 #ifdef WITH_CONTENT_SCAN
1464 no_mbox_unspool = FALSE; /* Can be set by ACL */
1466 submission_mode = FALSE; /* Can be set by ACL */
1467 suppress_local_fixups = suppress_local_fixups_default; /* Can be set by ACL */
1468 active_local_from_check = local_from_check; /* Can be set by ACL */
1469 active_local_sender_retain = local_sender_retain; /* Can be set by ACL */
1470 sender_address = NULL;
1471 submission_name = NULL; /* Can be set by ACL */
1472 raw_sender = NULL; /* After SMTP rewrite, before qualifying */
1473 sender_address_unrewritten = NULL; /* Set only after verify rewrite */
1474 sender_verified_list = NULL; /* No senders verified */
1475 memset(sender_address_cache, 0, sizeof(sender_address_cache));
1476 memset(sender_domain_cache, 0, sizeof(sender_domain_cache));
1477 authenticated_sender = NULL;
1478 #ifdef EXPERIMENTAL_BRIGHTMAIL
1480 bmi_verdicts = NULL;
1482 #ifndef DISABLE_DKIM
1483 dkim_signers = NULL;
1484 dkim_disable_verify = FALSE;
1485 dkim_collect_input = FALSE;
1487 #ifdef EXPERIMENTAL_SPF
1488 spf_header_comment = NULL;
1489 spf_received = NULL;
1491 spf_smtp_comment = NULL;
1493 body_linecount = body_zerocount = 0;
1495 sender_rate = sender_rate_limit = sender_rate_period = NULL;
1496 ratelimiters_mail = NULL; /* Updated by ratelimit ACL condition */
1497 /* Note that ratelimiters_conn persists across resets. */
1499 /* Reset message ACL variables */
1503 /* The message body variables use malloc store. They may be set if this is
1504 not the first message in an SMTP session and the previous message caused them
1505 to be referenced in an ACL. */
1507 if (message_body != NULL)
1509 store_free(message_body);
1510 message_body = NULL;
1513 if (message_body_end != NULL)
1515 store_free(message_body_end);
1516 message_body_end = NULL;
1519 /* Warning log messages are also saved in malloc store. They are saved to avoid
1520 repetition in the same message, but it seems right to repeat them for different
1523 while (acl_warn_logged != NULL)
1525 string_item *this = acl_warn_logged;
1526 acl_warn_logged = acl_warn_logged->next;
1535 /*************************************************
1536 * Initialize for incoming batched SMTP message *
1537 *************************************************/
1539 /* This function is called from smtp_setup_msg() in the case when
1540 smtp_batched_input is true. This happens when -bS is used to pass a whole batch
1541 of messages in one file with SMTP commands between them. All errors must be
1542 reported by sending a message, and only MAIL FROM, RCPT TO, and DATA are
1543 relevant. After an error on a sender, or an invalid recipient, the remainder
1544 of the message is skipped. The value of received_protocol is already set.
1547 Returns: > 0 message successfully started (reached DATA)
1548 = 0 QUIT read or end of file reached
1549 < 0 should not occur
1553 smtp_setup_batch_msg(void)
1556 void *reset_point = store_get(0);
1558 /* Save the line count at the start of each transaction - single commands
1559 like HELO and RSET count as whole transactions. */
1561 bsmtp_transaction_linecount = receive_linecount;
1563 if ((receive_feof)()) return 0; /* Treat EOF as QUIT */
1565 smtp_reset(reset_point); /* Reset for start of message */
1567 /* Deal with SMTP commands. This loop is exited by setting done to a POSITIVE
1568 value. The values are 2 larger than the required yield of the function. */
1573 uschar *recipient = NULL;
1574 int start, end, sender_domain, recipient_domain;
1576 switch(smtp_read_command(FALSE))
1578 /* The HELO/EHLO commands set sender_address_helo if they have
1579 valid data; otherwise they are ignored, except that they do
1580 a reset of the state. */
1585 check_helo(smtp_cmd_data);
1589 smtp_reset(reset_point);
1590 bsmtp_transaction_linecount = receive_linecount;
1594 /* The MAIL FROM command requires an address as an operand. All we
1595 do here is to parse it for syntactic correctness. The form "<>" is
1596 a special case which converts into an empty string. The start/end
1597 pointers in the original are not used further for this address, as
1598 it is the canonical extracted address which is all that is kept. */
1601 if (sender_address != NULL)
1602 /* The function moan_smtp_batch() does not return. */
1603 moan_smtp_batch(smtp_cmd_buffer, "503 Sender already given");
1605 if (smtp_cmd_data[0] == 0)
1606 /* The function moan_smtp_batch() does not return. */
1607 moan_smtp_batch(smtp_cmd_buffer, "501 MAIL FROM must have an address operand");
1609 /* Reset to start of message */
1611 smtp_reset(reset_point);
1613 /* Apply SMTP rewrite */
1615 raw_sender = ((rewrite_existflags & rewrite_smtp) != 0)?
1616 rewrite_one(smtp_cmd_data, rewrite_smtp|rewrite_smtp_sender, NULL, FALSE,
1617 US"", global_rewrite_rules) : smtp_cmd_data;
1619 /* Extract the address; the TRUE flag allows <> as valid */
1622 parse_extract_address(raw_sender, &errmess, &start, &end, &sender_domain,
1625 if (raw_sender == NULL)
1626 /* The function moan_smtp_batch() does not return. */
1627 moan_smtp_batch(smtp_cmd_buffer, "501 %s", errmess);
1629 sender_address = string_copy(raw_sender);
1631 /* Qualify unqualified sender addresses if permitted to do so. */
1633 if (sender_domain == 0 && sender_address[0] != 0 && sender_address[0] != '@')
1635 if (allow_unqualified_sender)
1637 sender_address = rewrite_address_qualify(sender_address, FALSE);
1638 DEBUG(D_receive) debug_printf("unqualified address %s accepted "
1639 "and rewritten\n", raw_sender);
1641 /* The function moan_smtp_batch() does not return. */
1642 else moan_smtp_batch(smtp_cmd_buffer, "501 sender address must contain "
1648 /* The RCPT TO command requires an address as an operand. All we do
1649 here is to parse it for syntactic correctness. There may be any number
1650 of RCPT TO commands, specifying multiple senders. We build them all into
1651 a data structure that is in argc/argv format. The start/end values
1652 given by parse_extract_address are not used, as we keep only the
1653 extracted address. */
1656 if (sender_address == NULL)
1657 /* The function moan_smtp_batch() does not return. */
1658 moan_smtp_batch(smtp_cmd_buffer, "503 No sender yet given");
1660 if (smtp_cmd_data[0] == 0)
1661 /* The function moan_smtp_batch() does not return. */
1662 moan_smtp_batch(smtp_cmd_buffer, "501 RCPT TO must have an address operand");
1664 /* Check maximum number allowed */
1666 if (recipients_max > 0 && recipients_count + 1 > recipients_max)
1667 /* The function moan_smtp_batch() does not return. */
1668 moan_smtp_batch(smtp_cmd_buffer, "%s too many recipients",
1669 recipients_max_reject? "552": "452");
1671 /* Apply SMTP rewrite, then extract address. Don't allow "<>" as a
1672 recipient address */
1674 recipient = ((rewrite_existflags & rewrite_smtp) != 0)?
1675 rewrite_one(smtp_cmd_data, rewrite_smtp, NULL, FALSE, US"",
1676 global_rewrite_rules) : smtp_cmd_data;
1678 /* rfc821_domains = TRUE; << no longer needed */
1679 recipient = parse_extract_address(recipient, &errmess, &start, &end,
1680 &recipient_domain, FALSE);
1681 /* rfc821_domains = FALSE; << no longer needed */
1683 if (recipient == NULL)
1684 /* The function moan_smtp_batch() does not return. */
1685 moan_smtp_batch(smtp_cmd_buffer, "501 %s", errmess);
1687 /* If the recipient address is unqualified, qualify it if permitted. Then
1688 add it to the list of recipients. */
1690 if (recipient_domain == 0)
1692 if (allow_unqualified_recipient)
1694 DEBUG(D_receive) debug_printf("unqualified address %s accepted\n",
1696 recipient = rewrite_address_qualify(recipient, TRUE);
1698 /* The function moan_smtp_batch() does not return. */
1699 else moan_smtp_batch(smtp_cmd_buffer, "501 recipient address must contain "
1702 receive_add_recipient(recipient, -1);
1706 /* The DATA command is legal only if it follows successful MAIL FROM
1707 and RCPT TO commands. This function is complete when a valid DATA
1708 command is encountered. */
1711 if (sender_address == NULL || recipients_count <= 0)
1713 /* The function moan_smtp_batch() does not return. */
1714 if (sender_address == NULL)
1715 moan_smtp_batch(smtp_cmd_buffer,
1716 "503 MAIL FROM:<sender> command must precede DATA");
1718 moan_smtp_batch(smtp_cmd_buffer,
1719 "503 RCPT TO:<recipient> must precede DATA");
1723 done = 3; /* DATA successfully achieved */
1724 message_ended = END_NOTENDED; /* Indicate in middle of message */
1729 /* The VRFY, EXPN, HELP, ETRN, and NOOP commands are ignored. */
1736 bsmtp_transaction_linecount = receive_linecount;
1747 /* The function moan_smtp_batch() does not return. */
1748 moan_smtp_batch(smtp_cmd_buffer, "501 Unexpected argument data");
1753 /* The function moan_smtp_batch() does not return. */
1754 moan_smtp_batch(smtp_cmd_buffer, "501 Unexpected NULL in SMTP command");
1759 /* The function moan_smtp_batch() does not return. */
1760 moan_smtp_batch(smtp_cmd_buffer, "500 Command unrecognized");
1765 return done - 2; /* Convert yield values */
1771 /*************************************************
1772 * Start an SMTP session *
1773 *************************************************/
1775 /* This function is called at the start of an SMTP session. Thereafter,
1776 smtp_setup_msg() is called to initiate each separate message. This
1777 function does host-specific testing, and outputs the banner line.
1780 Returns: FALSE if the session can not continue; something has
1781 gone wrong, or the connection to the host is blocked
1785 smtp_start_session(void)
1789 uschar *user_msg, *log_msg;
1793 smtp_connection_start = time(NULL);
1794 for (smtp_ch_index = 0; smtp_ch_index < SMTP_HBUFF_SIZE; smtp_ch_index++)
1795 smtp_connection_had[smtp_ch_index] = SCH_NONE;
1798 /* Default values for certain variables */
1800 helo_seen = esmtp = helo_accept_junk = FALSE;
1801 smtp_mailcmd_count = 0;
1802 count_nonmail = TRUE_UNSET;
1803 synprot_error_count = unknown_command_count = nonmail_command_count = 0;
1804 smtp_delay_mail = smtp_rlm_base;
1805 auth_advertised = FALSE;
1806 pipelining_advertised = FALSE;
1807 pipelining_enable = TRUE;
1808 sync_cmd_limit = NON_SYNC_CMD_NON_PIPELINING;
1809 smtp_exit_function_called = FALSE; /* For avoiding loop in not-quit exit */
1811 memset(sender_host_cache, 0, sizeof(sender_host_cache));
1813 /* If receiving by -bs from a trusted user, or testing with -bh, we allow
1814 authentication settings from -oMaa to remain in force. */
1816 if (!host_checking && !sender_host_notsocket) sender_host_authenticated = NULL;
1817 authenticated_by = NULL;
1820 tls_in.cipher = tls_in.peerdn = NULL;
1821 tls_in.ourcert = tls_in.peercert = NULL;
1823 tls_in.ocsp = OCSP_NOT_REQ;
1824 tls_advertised = FALSE;
1827 /* Reset ACL connection variables */
1831 /* Allow for trailing 0 in the command and data buffers. */
1833 smtp_cmd_buffer = (uschar *)malloc(2*smtp_cmd_buffer_size + 2);
1834 if (smtp_cmd_buffer == NULL)
1835 log_write(0, LOG_MAIN|LOG_PANIC_DIE,
1836 "malloc() failed for SMTP command buffer");
1837 smtp_cmd_buffer[0] = 0;
1838 smtp_data_buffer = smtp_cmd_buffer + smtp_cmd_buffer_size + 1;
1840 /* For batched input, the protocol setting can be overridden from the
1841 command line by a trusted caller. */
1843 if (smtp_batched_input)
1845 if (received_protocol == NULL) received_protocol = US"local-bsmtp";
1848 /* For non-batched SMTP input, the protocol setting is forced here. It will be
1849 reset later if any of EHLO/AUTH/STARTTLS are received. */
1853 protocols[pnormal] + ((sender_host_address != NULL)? pnlocal : 0);
1855 /* Set up the buffer for inputting using direct read() calls, and arrange to
1856 call the local functions instead of the standard C ones. */
1858 smtp_inbuffer = (uschar *)malloc(in_buffer_size);
1859 if (smtp_inbuffer == NULL)
1860 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "malloc() failed for SMTP input buffer");
1861 receive_getc = smtp_getc;
1862 receive_ungetc = smtp_ungetc;
1863 receive_feof = smtp_feof;
1864 receive_ferror = smtp_ferror;
1865 receive_smtp_buffered = smtp_buffered;
1866 smtp_inptr = smtp_inend = smtp_inbuffer;
1867 smtp_had_eof = smtp_had_error = 0;
1869 /* Set up the message size limit; this may be host-specific */
1871 thismessage_size_limit = expand_string_integer(message_size_limit, TRUE);
1872 if (expand_string_message != NULL)
1874 if (thismessage_size_limit == -1)
1875 log_write(0, LOG_MAIN|LOG_PANIC, "unable to expand message_size_limit: "
1876 "%s", expand_string_message);
1878 log_write(0, LOG_MAIN|LOG_PANIC, "invalid message_size_limit: "
1879 "%s", expand_string_message);
1880 smtp_closedown(US"Temporary local problem - please try later");
1884 /* When a message is input locally via the -bs or -bS options, sender_host_
1885 unknown is set unless -oMa was used to force an IP address, in which case it
1886 is checked like a real remote connection. When -bs is used from inetd, this
1887 flag is not set, causing the sending host to be checked. The code that deals
1888 with IP source routing (if configured) is never required for -bs or -bS and
1889 the flag sender_host_notsocket is used to suppress it.
1891 If smtp_accept_max and smtp_accept_reserve are set, keep some connections in
1892 reserve for certain hosts and/or networks. */
1894 if (!sender_host_unknown)
1897 BOOL reserved_host = FALSE;
1899 /* Look up IP options (source routing info) on the socket if this is not an
1900 -oMa "host", and if any are found, log them and drop the connection.
1902 Linux (and others now, see below) is different to everyone else, so there
1903 has to be some conditional compilation here. Versions of Linux before 2.1.15
1904 used a structure whose name was "options". Somebody finally realized that
1905 this name was silly, and it got changed to "ip_options". I use the
1906 newer name here, but there is a fudge in the script that sets up os.h
1907 to define a macro in older Linux systems.
1909 Sigh. Linux is a fast-moving target. Another generation of Linux uses
1910 glibc 2, which has chosen ip_opts for the structure name. This is now
1911 really a glibc thing rather than a Linux thing, so the condition name
1912 has been changed to reflect this. It is relevant also to GNU/Hurd.
1914 Mac OS 10.x (Darwin) is like the later glibc versions, but without the
1915 setting of the __GLIBC__ macro, so we can't detect it automatically. There's
1916 a special macro defined in the os.h file.
1918 Some DGUX versions on older hardware appear not to support IP options at
1919 all, so there is now a general macro which can be set to cut out this
1922 How to do this properly in IPv6 is not yet known. */
1924 #if !HAVE_IPV6 && !defined(NO_IP_OPTIONS)
1926 #ifdef GLIBC_IP_OPTIONS
1927 #if (!defined __GLIBC__) || (__GLIBC__ < 2)
1932 #elif defined DARWIN_IP_OPTIONS
1938 if (!host_checking && !sender_host_notsocket)
1941 EXIM_SOCKLEN_T optlen = sizeof(struct ip_options) + MAX_IPOPTLEN;
1942 struct ip_options *ipopt = store_get(optlen);
1944 struct ip_opts ipoptblock;
1945 struct ip_opts *ipopt = &ipoptblock;
1946 EXIM_SOCKLEN_T optlen = sizeof(ipoptblock);
1948 struct ipoption ipoptblock;
1949 struct ipoption *ipopt = &ipoptblock;
1950 EXIM_SOCKLEN_T optlen = sizeof(ipoptblock);
1953 /* Occasional genuine failures of getsockopt() have been seen - for
1954 example, "reset by peer". Therefore, just log and give up on this
1955 call, unless the error is ENOPROTOOPT. This error is given by systems
1956 that have the interfaces but not the mechanism - e.g. GNU/Hurd at the time
1957 of writing. So for that error, carry on - we just can't do an IP options
1960 DEBUG(D_receive) debug_printf("checking for IP options\n");
1962 if (getsockopt(fileno(smtp_out), IPPROTO_IP, IP_OPTIONS, (uschar *)(ipopt),
1965 if (errno != ENOPROTOOPT)
1967 log_write(0, LOG_MAIN, "getsockopt() failed from %s: %s",
1968 host_and_ident(FALSE), strerror(errno));
1969 smtp_printf("451 SMTP service not available\r\n");
1974 /* Deal with any IP options that are set. On the systems I have looked at,
1975 the value of MAX_IPOPTLEN has been 40, meaning that there should never be
1976 more logging data than will fit in big_buffer. Nevertheless, after somebody
1977 questioned this code, I've added in some paranoid checking. */
1979 else if (optlen > 0)
1981 uschar *p = big_buffer;
1982 uschar *pend = big_buffer + big_buffer_size;
1983 uschar *opt, *adptr;
1985 struct in_addr addr;
1988 uschar *optstart = (uschar *)(ipopt->__data);
1990 uschar *optstart = (uschar *)(ipopt->ip_opts);
1992 uschar *optstart = (uschar *)(ipopt->ipopt_list);
1995 DEBUG(D_receive) debug_printf("IP options exist\n");
1997 Ustrcpy(p, "IP options on incoming call:");
2000 for (opt = optstart; opt != NULL &&
2001 opt < (uschar *)(ipopt) + optlen;)
2015 if (!string_format(p, pend-p, " %s [@%s",
2016 (*opt == IPOPT_SSRR)? "SSRR" : "LSRR",
2018 inet_ntoa(*((struct in_addr *)(&(ipopt->faddr))))))
2020 inet_ntoa(ipopt->ip_dst)))
2022 inet_ntoa(ipopt->ipopt_dst)))
2030 optcount = (opt[1] - 3) / sizeof(struct in_addr);
2032 while (optcount-- > 0)
2034 memcpy(&addr, adptr, sizeof(addr));
2035 if (!string_format(p, pend - p - 1, "%s%s",
2036 (optcount == 0)? ":" : "@", inet_ntoa(addr)))
2042 adptr += sizeof(struct in_addr);
2051 if (pend - p < 4 + 3*opt[1]) { opt = NULL; break; }
2054 for (i = 0; i < opt[1]; i++)
2056 sprintf(CS p, "%2.2x ", opt[i]);
2067 log_write(0, LOG_MAIN, "%s", big_buffer);
2069 /* Refuse any call with IP options. This is what tcpwrappers 7.5 does. */
2071 log_write(0, LOG_MAIN|LOG_REJECT,
2072 "connection from %s refused (IP options)", host_and_ident(FALSE));
2074 smtp_printf("554 SMTP service not available\r\n");
2078 /* Length of options = 0 => there are no options */
2080 else DEBUG(D_receive) debug_printf("no IP options found\n");
2082 #endif /* HAVE_IPV6 && !defined(NO_IP_OPTIONS) */
2084 /* Set keep-alive in socket options. The option is on by default. This
2085 setting is an attempt to get rid of some hanging connections that stick in
2086 read() when the remote end (usually a dialup) goes away. */
2088 if (smtp_accept_keepalive && !sender_host_notsocket)
2089 ip_keepalive(fileno(smtp_out), sender_host_address, FALSE);
2091 /* If the current host matches host_lookup, set the name by doing a
2092 reverse lookup. On failure, sender_host_name will be NULL and
2093 host_lookup_failed will be TRUE. This may or may not be serious - optional
2096 if (verify_check_host(&host_lookup) == OK)
2098 (void)host_name_lookup();
2099 host_build_sender_fullhost();
2102 /* Delay this until we have the full name, if it is looked up. */
2104 set_process_info("handling incoming connection from %s",
2105 host_and_ident(FALSE));
2107 /* Start up TLS if tls_on_connect is set. This is for supporting the legacy
2108 smtps port for use with older style SSL MTAs. */
2111 if (tls_in.on_connect && tls_server_start(tls_require_ciphers) != OK)
2115 /* Test for explicit connection rejection */
2117 if (verify_check_host(&host_reject_connection) == OK)
2119 log_write(L_connection_reject, LOG_MAIN|LOG_REJECT, "refused connection "
2120 "from %s (host_reject_connection)", host_and_ident(FALSE));
2121 smtp_printf("554 SMTP service not available\r\n");
2125 /* Test with TCP Wrappers if so configured. There is a problem in that
2126 hosts_ctl() returns 0 (deny) under a number of system failure circumstances,
2127 such as disks dying. In these cases, it is desirable to reject with a 4xx
2128 error instead of a 5xx error. There isn't a "right" way to detect such
2129 problems. The following kludge is used: errno is zeroed before calling
2130 hosts_ctl(). If the result is "reject", a 5xx error is given only if the
2131 value of errno is 0 or ENOENT (which happens if /etc/hosts.{allow,deny} does
2134 #ifdef USE_TCP_WRAPPERS
2136 tcp_wrappers_name = expand_string(tcp_wrappers_daemon_name);
2137 if (tcp_wrappers_name == NULL)
2139 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "Expansion of \"%s\" "
2140 "(tcp_wrappers_name) failed: %s", string_printing(tcp_wrappers_name),
2141 expand_string_message);
2143 if (!hosts_ctl(tcp_wrappers_name,
2144 (sender_host_name == NULL)? STRING_UNKNOWN : CS sender_host_name,
2145 (sender_host_address == NULL)? STRING_UNKNOWN : CS sender_host_address,
2146 (sender_ident == NULL)? STRING_UNKNOWN : CS sender_ident))
2148 if (errno == 0 || errno == ENOENT)
2150 HDEBUG(D_receive) debug_printf("tcp wrappers rejection\n");
2151 log_write(L_connection_reject,
2152 LOG_MAIN|LOG_REJECT, "refused connection from %s "
2153 "(tcp wrappers)", host_and_ident(FALSE));
2154 smtp_printf("554 SMTP service not available\r\n");
2158 int save_errno = errno;
2159 HDEBUG(D_receive) debug_printf("tcp wrappers rejected with unexpected "
2160 "errno value %d\n", save_errno);
2161 log_write(L_connection_reject,
2162 LOG_MAIN|LOG_REJECT, "temporarily refused connection from %s "
2163 "(tcp wrappers errno=%d)", host_and_ident(FALSE), save_errno);
2164 smtp_printf("451 Temporary local problem - please try later\r\n");
2170 /* Check for reserved slots. The value of smtp_accept_count has already been
2171 incremented to include this process. */
2173 if (smtp_accept_max > 0 &&
2174 smtp_accept_count > smtp_accept_max - smtp_accept_reserve)
2176 if ((rc = verify_check_host(&smtp_reserve_hosts)) != OK)
2178 log_write(L_connection_reject,
2179 LOG_MAIN, "temporarily refused connection from %s: not in "
2180 "reserve list: connected=%d max=%d reserve=%d%s",
2181 host_and_ident(FALSE), smtp_accept_count - 1, smtp_accept_max,
2182 smtp_accept_reserve, (rc == DEFER)? " (lookup deferred)" : "");
2183 smtp_printf("421 %s: Too many concurrent SMTP connections; "
2184 "please try again later\r\n", smtp_active_hostname);
2187 reserved_host = TRUE;
2190 /* If a load level above which only messages from reserved hosts are
2191 accepted is set, check the load. For incoming calls via the daemon, the
2192 check is done in the superior process if there are no reserved hosts, to
2193 save a fork. In all cases, the load average will already be available
2194 in a global variable at this point. */
2196 if (smtp_load_reserve >= 0 &&
2197 load_average > smtp_load_reserve &&
2199 verify_check_host(&smtp_reserve_hosts) != OK)
2201 log_write(L_connection_reject,
2202 LOG_MAIN, "temporarily refused connection from %s: not in "
2203 "reserve list and load average = %.2f", host_and_ident(FALSE),
2204 (double)load_average/1000.0);
2205 smtp_printf("421 %s: Too much load; please try again later\r\n",
2206 smtp_active_hostname);
2210 /* Determine whether unqualified senders or recipients are permitted
2211 for this host. Unfortunately, we have to do this every time, in order to
2212 set the flags so that they can be inspected when considering qualifying
2213 addresses in the headers. For a site that permits no qualification, this
2214 won't take long, however. */
2216 allow_unqualified_sender =
2217 verify_check_host(&sender_unqualified_hosts) == OK;
2219 allow_unqualified_recipient =
2220 verify_check_host(&recipient_unqualified_hosts) == OK;
2222 /* Determine whether HELO/EHLO is required for this host. The requirement
2223 can be hard or soft. */
2225 helo_required = verify_check_host(&helo_verify_hosts) == OK;
2227 helo_verify = verify_check_host(&helo_try_verify_hosts) == OK;
2229 /* Determine whether this hosts is permitted to send syntactic junk
2230 after a HELO or EHLO command. */
2232 helo_accept_junk = verify_check_host(&helo_accept_junk_hosts) == OK;
2235 /* For batch SMTP input we are now done. */
2237 if (smtp_batched_input) return TRUE;
2239 #ifdef EXPERIMENTAL_PROXY
2240 /* If valid Proxy Protocol source is connecting, set up session.
2241 * Failure will not allow any SMTP function other than QUIT. */
2242 proxy_session = FALSE;
2243 proxy_session_failed = FALSE;
2244 if (check_proxy_protocol_host())
2246 if (setup_proxy_protocol_host() == FALSE)
2248 proxy_session_failed = TRUE;
2250 debug_printf("Failure to extract proxied host, only QUIT allowed\n");
2254 sender_host_name = NULL;
2255 (void)host_name_lookup();
2256 host_build_sender_fullhost();
2261 /* Run the ACL if it exists */
2264 if (acl_smtp_connect != NULL)
2267 rc = acl_check(ACL_WHERE_CONNECT, NULL, acl_smtp_connect, &user_msg,
2271 (void)smtp_handle_acl_fail(ACL_WHERE_CONNECT, rc, user_msg, log_msg);
2276 /* Output the initial message for a two-way SMTP connection. It may contain
2277 newlines, which then cause a multi-line response to be given. */
2279 code = US"220"; /* Default status code */
2280 esc = US""; /* Default extended status code */
2281 esclen = 0; /* Length of esc */
2283 if (user_msg == NULL)
2285 s = expand_string(smtp_banner);
2287 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "Expansion of \"%s\" (smtp_banner) "
2288 "failed: %s", smtp_banner, expand_string_message);
2294 smtp_message_code(&code, &codelen, &s, NULL);
2298 esclen = codelen - 4;
2302 /* Remove any terminating newlines; might as well remove trailing space too */
2305 while (p > s && isspace(p[-1])) p--;
2308 /* It seems that CC:Mail is braindead, and assumes that the greeting message
2309 is all contained in a single IP packet. The original code wrote out the
2310 greeting using several calls to fprint/fputc, and on busy servers this could
2311 cause it to be split over more than one packet - which caused CC:Mail to fall
2312 over when it got the second part of the greeting after sending its first
2313 command. Sigh. To try to avoid this, build the complete greeting message
2314 first, and output it in one fell swoop. This gives a better chance of it
2315 ending up as a single packet. */
2317 ss = store_get(size);
2321 do /* At least once, in case we have an empty string */
2324 uschar *linebreak = Ustrchr(p, '\n');
2325 ss = string_cat(ss, &size, &ptr, code, 3);
2326 if (linebreak == NULL)
2329 ss = string_cat(ss, &size, &ptr, US" ", 1);
2333 len = linebreak - p;
2334 ss = string_cat(ss, &size, &ptr, US"-", 1);
2336 ss = string_cat(ss, &size, &ptr, esc, esclen);
2337 ss = string_cat(ss, &size, &ptr, p, len);
2338 ss = string_cat(ss, &size, &ptr, US"\r\n", 2);
2340 if (linebreak != NULL) p++;
2344 ss[ptr] = 0; /* string_cat leaves room for this */
2346 /* Before we write the banner, check that there is no input pending, unless
2347 this synchronisation check is disabled. */
2351 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP protocol "
2352 "synchronization error (input sent without waiting for greeting): "
2353 "rejected connection from %s input=\"%s\"", host_and_ident(TRUE),
2354 string_printing(smtp_inptr));
2355 smtp_printf("554 SMTP synchronization error\r\n");
2359 /* Now output the banner */
2361 smtp_printf("%s", ss);
2369 /*************************************************
2370 * Handle SMTP syntax and protocol errors *
2371 *************************************************/
2373 /* Write to the log for SMTP syntax errors in incoming commands, if configured
2374 to do so. Then transmit the error response. The return value depends on the
2375 number of syntax and protocol errors in this SMTP session.
2378 type error type, given as a log flag bit
2379 code response code; <= 0 means don't send a response
2380 data data to reflect in the response (can be NULL)
2381 errmess the error message
2383 Returns: -1 limit of syntax/protocol errors NOT exceeded
2384 +1 limit of syntax/protocol errors IS exceeded
2386 These values fit in with the values of the "done" variable in the main
2387 processing loop in smtp_setup_msg(). */
2390 synprot_error(int type, int code, uschar *data, uschar *errmess)
2394 log_write(type, LOG_MAIN, "SMTP %s error in \"%s\" %s %s",
2395 (type == L_smtp_syntax_error)? "syntax" : "protocol",
2396 string_printing(smtp_cmd_buffer), host_and_ident(TRUE), errmess);
2398 if (++synprot_error_count > smtp_max_synprot_errors)
2401 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
2402 "syntax or protocol errors (last command was \"%s\")",
2403 host_and_ident(FALSE), smtp_cmd_buffer);
2408 smtp_printf("%d%c%s%s%s\r\n", code, (yield == 1)? '-' : ' ',
2409 (data == NULL)? US"" : data, (data == NULL)? US"" : US": ", errmess);
2411 smtp_printf("%d Too many syntax or protocol errors\r\n", code);
2420 /*************************************************
2421 * Log incomplete transactions *
2422 *************************************************/
2424 /* This function is called after a transaction has been aborted by RSET, QUIT,
2425 connection drops or other errors. It logs the envelope information received
2426 so far in order to preserve address verification attempts.
2428 Argument: string to indicate what aborted the transaction
2433 incomplete_transaction_log(uschar *what)
2435 if (sender_address == NULL || /* No transaction in progress */
2436 (log_write_selector & L_smtp_incomplete_transaction) == 0 /* Not logging */
2439 /* Build list of recipients for logging */
2441 if (recipients_count > 0)
2444 raw_recipients = store_get(recipients_count * sizeof(uschar *));
2445 for (i = 0; i < recipients_count; i++)
2446 raw_recipients[i] = recipients_list[i].address;
2447 raw_recipients_count = recipients_count;
2450 log_write(L_smtp_incomplete_transaction, LOG_MAIN|LOG_SENDER|LOG_RECIPIENTS,
2451 "%s incomplete transaction (%s)", host_and_ident(TRUE), what);
2457 /*************************************************
2458 * Send SMTP response, possibly multiline *
2459 *************************************************/
2461 /* There are, it seems, broken clients out there that cannot handle multiline
2462 responses. If no_multiline_responses is TRUE (it can be set from an ACL), we
2463 output nothing for non-final calls, and only the first line for anything else.
2466 code SMTP code, may involve extended status codes
2467 codelen length of smtp code; if > 4 there's an ESC
2468 final FALSE if the last line isn't the final line
2469 msg message text, possibly containing newlines
2475 smtp_respond(uschar* code, int codelen, BOOL final, uschar *msg)
2480 if (!final && no_multiline_responses) return;
2485 esclen = codelen - 4;
2488 /* If this is the first output for a (non-batch) RCPT command, see if all RCPTs
2489 have had the same. Note: this code is also present in smtp_printf(). It would
2490 be tidier to have it only in one place, but when it was added, it was easier to
2491 do it that way, so as not to have to mess with the code for the RCPT command,
2492 which sometimes uses smtp_printf() and sometimes smtp_respond(). */
2494 if (rcpt_in_progress)
2496 if (rcpt_smtp_response == NULL)
2497 rcpt_smtp_response = string_copy(msg);
2498 else if (rcpt_smtp_response_same &&
2499 Ustrcmp(rcpt_smtp_response, msg) != 0)
2500 rcpt_smtp_response_same = FALSE;
2501 rcpt_in_progress = FALSE;
2504 /* Not output the message, splitting it up into multiple lines if necessary. */
2508 uschar *nl = Ustrchr(msg, '\n');
2511 smtp_printf("%.3s%c%.*s%s\r\n", code, final? ' ':'-', esclen, esc, msg);
2514 else if (nl[1] == 0 || no_multiline_responses)
2516 smtp_printf("%.3s%c%.*s%.*s\r\n", code, final? ' ':'-', esclen, esc,
2517 (int)(nl - msg), msg);
2522 smtp_printf("%.3s-%.*s%.*s\r\n", code, esclen, esc, (int)(nl - msg), msg);
2524 while (isspace(*msg)) msg++;
2532 /*************************************************
2533 * Parse user SMTP message *
2534 *************************************************/
2536 /* This function allows for user messages overriding the response code details
2537 by providing a suitable response code string at the start of the message
2538 user_msg. Check the message for starting with a response code and optionally an
2539 extended status code. If found, check that the first digit is valid, and if so,
2540 change the code pointer and length to use the replacement. An invalid code
2541 causes a panic log; in this case, if the log messages is the same as the user
2542 message, we must also adjust the value of the log message to show the code that
2543 is actually going to be used (the original one).
2545 This function is global because it is called from receive.c as well as within
2548 Note that the code length returned includes the terminating whitespace
2549 character, which is always included in the regex match.
2552 code SMTP code, may involve extended status codes
2553 codelen length of smtp code; if > 4 there's an ESC
2555 log_msg optional log message, to be adjusted with the new SMTP code
2561 smtp_message_code(uschar **code, int *codelen, uschar **msg, uschar **log_msg)
2566 if (msg == NULL || *msg == NULL) return;
2568 n = pcre_exec(regex_smtp_code, NULL, CS *msg, Ustrlen(*msg), 0,
2569 PCRE_EOPT, ovector, sizeof(ovector)/sizeof(int));
2572 if ((*msg)[0] != (*code)[0])
2574 log_write(0, LOG_MAIN|LOG_PANIC, "configured error code starts with "
2575 "incorrect digit (expected %c) in \"%s\"", (*code)[0], *msg);
2576 if (log_msg != NULL && *log_msg == *msg)
2577 *log_msg = string_sprintf("%s %s", *code, *log_msg + ovector[1]);
2582 *codelen = ovector[1]; /* Includes final space */
2584 *msg += ovector[1]; /* Chop the code off the message */
2591 /*************************************************
2592 * Handle an ACL failure *
2593 *************************************************/
2595 /* This function is called when acl_check() fails. As well as calls from within
2596 this module, it is called from receive.c for an ACL after DATA. It sorts out
2597 logging the incident, and sets up the error response. A message containing
2598 newlines is turned into a multiline SMTP response, but for logging, only the
2601 There's a table of default permanent failure response codes to use in
2602 globals.c, along with the table of names. VFRY is special. Despite RFC1123 it
2603 defaults disabled in Exim. However, discussion in connection with RFC 821bis
2604 (aka RFC 2821) has concluded that the response should be 252 in the disabled
2605 state, because there are broken clients that try VRFY before RCPT. A 5xx
2606 response should be given only when the address is positively known to be
2607 undeliverable. Sigh. Also, for ETRN, 458 is given on refusal, and for AUTH,
2610 From Exim 4.63, it is possible to override the response code details by
2611 providing a suitable response code string at the start of the message provided
2612 in user_msg. The code's first digit is checked for validity.
2615 where where the ACL was called from
2617 user_msg a message that can be included in an SMTP response
2618 log_msg a message for logging
2620 Returns: 0 in most cases
2621 2 if the failure code was FAIL_DROP, in which case the
2622 SMTP connection should be dropped (this value fits with the
2623 "done" variable in smtp_setup_msg() below)
2627 smtp_handle_acl_fail(int where, int rc, uschar *user_msg, uschar *log_msg)
2629 BOOL drop = rc == FAIL_DROP;
2633 uschar *sender_info = US"";
2635 #ifdef WITH_CONTENT_SCAN
2636 (where == ACL_WHERE_MIME)? US"during MIME ACL checks" :
2638 (where == ACL_WHERE_PREDATA)? US"DATA" :
2639 (where == ACL_WHERE_DATA)? US"after DATA" :
2640 #ifdef EXPERIMENTAL_PRDR
2641 (where == ACL_WHERE_PRDR)? US"after DATA PRDR" :
2643 (smtp_cmd_data == NULL)?
2644 string_sprintf("%s in \"connect\" ACL", acl_wherenames[where]) :
2645 string_sprintf("%s %s", acl_wherenames[where], smtp_cmd_data);
2647 if (drop) rc = FAIL;
2649 /* Set the default SMTP code, and allow a user message to change it. */
2651 smtp_code = (rc != FAIL)? US"451" : acl_wherecodes[where];
2652 smtp_message_code(&smtp_code, &codelen, &user_msg, &log_msg);
2654 /* We used to have sender_address here; however, there was a bug that was not
2655 updating sender_address after a rewrite during a verify. When this bug was
2656 fixed, sender_address at this point became the rewritten address. I'm not sure
2657 this is what should be logged, so I've changed to logging the unrewritten
2658 address to retain backward compatibility. */
2660 #ifndef WITH_CONTENT_SCAN
2661 if (where == ACL_WHERE_RCPT || where == ACL_WHERE_DATA)
2663 if (where == ACL_WHERE_RCPT || where == ACL_WHERE_DATA || where == ACL_WHERE_MIME)
2666 sender_info = string_sprintf("F=<%s>%s%s%s%s ",
2667 sender_address_unrewritten ? sender_address_unrewritten : sender_address,
2668 sender_host_authenticated ? US" A=" : US"",
2669 sender_host_authenticated ? sender_host_authenticated : US"",
2670 sender_host_authenticated && authenticated_id ? US":" : US"",
2671 sender_host_authenticated && authenticated_id ? authenticated_id : US""
2675 /* If there's been a sender verification failure with a specific message, and
2676 we have not sent a response about it yet, do so now, as a preliminary line for
2677 failures, but not defers. However, always log it for defer, and log it for fail
2678 unless the sender_verify_fail log selector has been turned off. */
2680 if (sender_verified_failed != NULL &&
2681 !testflag(sender_verified_failed, af_sverify_told))
2683 BOOL save_rcpt_in_progress = rcpt_in_progress;
2684 rcpt_in_progress = FALSE; /* So as not to treat these as the error */
2686 setflag(sender_verified_failed, af_sverify_told);
2688 if (rc != FAIL || (log_extra_selector & LX_sender_verify_fail) != 0)
2689 log_write(0, LOG_MAIN|LOG_REJECT, "%s sender verify %s for <%s>%s",
2690 host_and_ident(TRUE),
2691 ((sender_verified_failed->special_action & 255) == DEFER)? "defer":"fail",
2692 sender_verified_failed->address,
2693 (sender_verified_failed->message == NULL)? US"" :
2694 string_sprintf(": %s", sender_verified_failed->message));
2696 if (rc == FAIL && sender_verified_failed->user_message != NULL)
2697 smtp_respond(smtp_code, codelen, FALSE, string_sprintf(
2698 testflag(sender_verified_failed, af_verify_pmfail)?
2699 "Postmaster verification failed while checking <%s>\n%s\n"
2700 "Several RFCs state that you are required to have a postmaster\n"
2701 "mailbox for each mail domain. This host does not accept mail\n"
2702 "from domains whose servers reject the postmaster address."
2704 testflag(sender_verified_failed, af_verify_nsfail)?
2705 "Callback setup failed while verifying <%s>\n%s\n"
2706 "The initial connection, or a HELO or MAIL FROM:<> command was\n"
2707 "rejected. Refusing MAIL FROM:<> does not help fight spam, disregards\n"
2708 "RFC requirements, and stops you from receiving standard bounce\n"
2709 "messages. This host does not accept mail from domains whose servers\n"
2712 "Verification failed for <%s>\n%s",
2713 sender_verified_failed->address,
2714 sender_verified_failed->user_message));
2716 rcpt_in_progress = save_rcpt_in_progress;
2719 /* Sort out text for logging */
2721 log_msg = (log_msg == NULL)? US"" : string_sprintf(": %s", log_msg);
2722 lognl = Ustrchr(log_msg, '\n');
2723 if (lognl != NULL) *lognl = 0;
2725 /* Send permanent failure response to the command, but the code used isn't
2726 always a 5xx one - see comments at the start of this function. If the original
2727 rc was FAIL_DROP we drop the connection and yield 2. */
2729 if (rc == FAIL) smtp_respond(smtp_code, codelen, TRUE, (user_msg == NULL)?
2730 US"Administrative prohibition" : user_msg);
2732 /* Send temporary failure response to the command. Don't give any details,
2733 unless acl_temp_details is set. This is TRUE for a callout defer, a "defer"
2734 verb, and for a header verify when smtp_return_error_details is set.
2736 This conditional logic is all somewhat of a mess because of the odd
2737 interactions between temp_details and return_error_details. One day it should
2738 be re-implemented in a tidier fashion. */
2742 if (acl_temp_details && user_msg != NULL)
2744 if (smtp_return_error_details &&
2745 sender_verified_failed != NULL &&
2746 sender_verified_failed->message != NULL)
2748 smtp_respond(smtp_code, codelen, FALSE, sender_verified_failed->message);
2750 smtp_respond(smtp_code, codelen, TRUE, user_msg);
2753 smtp_respond(smtp_code, codelen, TRUE,
2754 US"Temporary local problem - please try later");
2757 /* Log the incident to the logs that are specified by log_reject_target
2758 (default main, reject). This can be empty to suppress logging of rejections. If
2759 the connection is not forcibly to be dropped, return 0. Otherwise, log why it
2760 is closing if required and return 2. */
2762 if (log_reject_target != 0)
2765 uschar * s = s_tlslog(NULL, NULL, NULL);
2770 log_write(0, log_reject_target, "%s%s %s%srejected %s%s",
2771 host_and_ident(TRUE), s,
2772 sender_info, (rc == FAIL)? US"" : US"temporarily ", what, log_msg);
2775 if (!drop) return 0;
2777 log_write(L_smtp_connection, LOG_MAIN, "%s closed by DROP in ACL",
2778 smtp_get_connection_info());
2780 /* Run the not-quit ACL, but without any custom messages. This should not be a
2781 problem, because we get here only if some other ACL has issued "drop", and
2782 in that case, *its* custom messages will have been used above. */
2784 smtp_notquit_exit(US"acl-drop", NULL, NULL);
2791 /*************************************************
2792 * Handle SMTP exit when QUIT is not given *
2793 *************************************************/
2795 /* This function provides a logging/statistics hook for when an SMTP connection
2796 is dropped on the floor or the other end goes away. It's a global function
2797 because it's called from receive.c as well as this module. As well as running
2798 the NOTQUIT ACL, if there is one, this function also outputs a final SMTP
2799 response, either with a custom message from the ACL, or using a default. There
2800 is one case, however, when no message is output - after "drop". In that case,
2801 the ACL that obeyed "drop" has already supplied the custom message, and NULL is
2802 passed to this function.
2804 In case things go wrong while processing this function, causing an error that
2805 may re-enter this funtion, there is a recursion check.
2808 reason What $smtp_notquit_reason will be set to in the ACL;
2809 if NULL, the ACL is not run
2810 code The error code to return as part of the response
2811 defaultrespond The default message if there's no user_msg
2817 smtp_notquit_exit(uschar *reason, uschar *code, uschar *defaultrespond, ...)
2820 uschar *user_msg = NULL;
2821 uschar *log_msg = NULL;
2823 /* Check for recursive acll */
2825 if (smtp_exit_function_called)
2827 log_write(0, LOG_PANIC, "smtp_notquit_exit() called more than once (%s)",
2831 smtp_exit_function_called = TRUE;
2833 /* Call the not-QUIT ACL, if there is one, unless no reason is given. */
2835 if (acl_smtp_notquit != NULL && reason != NULL)
2837 smtp_notquit_reason = reason;
2838 rc = acl_check(ACL_WHERE_NOTQUIT, NULL, acl_smtp_notquit, &user_msg,
2841 log_write(0, LOG_MAIN|LOG_PANIC, "ACL for not-QUIT returned ERROR: %s",
2845 /* Write an SMTP response if we are expected to give one. As the default
2846 responses are all internal, they should always fit in the buffer, but code a
2847 warning, just in case. Note that string_vformat() still leaves a complete
2848 string, even if it is incomplete. */
2850 if (code != NULL && defaultrespond != NULL)
2852 if (user_msg == NULL)
2856 va_start(ap, defaultrespond);
2857 if (!string_vformat(buffer, sizeof(buffer), CS defaultrespond, ap))
2858 log_write(0, LOG_MAIN|LOG_PANIC, "string too large in smtp_notquit_exit()");
2859 smtp_printf("%s %s\r\n", code, buffer);
2863 smtp_respond(code, 3, TRUE, user_msg);
2871 /*************************************************
2872 * Verify HELO argument *
2873 *************************************************/
2875 /* This function is called if helo_verify_hosts or helo_try_verify_hosts is
2876 matched. It is also called from ACL processing if verify = helo is used and
2877 verification was not previously tried (i.e. helo_try_verify_hosts was not
2878 matched). The result of its processing is to set helo_verified and
2879 helo_verify_failed. These variables should both be FALSE for this function to
2882 Note that EHLO/HELO is legitimately allowed to quote an address literal. Allow
2883 for IPv6 ::ffff: literals.
2886 Returns: TRUE if testing was completed;
2887 FALSE on a temporary failure
2891 smtp_verify_helo(void)
2895 HDEBUG(D_receive) debug_printf("verifying EHLO/HELO argument \"%s\"\n",
2898 if (sender_helo_name == NULL)
2900 HDEBUG(D_receive) debug_printf("no EHLO/HELO command was issued\n");
2903 /* Deal with the case of -bs without an IP address */
2905 else if (sender_host_address == NULL)
2907 HDEBUG(D_receive) debug_printf("no client IP address: assume success\n");
2908 helo_verified = TRUE;
2911 /* Deal with the more common case when there is a sending IP address */
2913 else if (sender_helo_name[0] == '[')
2915 helo_verified = Ustrncmp(sender_helo_name+1, sender_host_address,
2916 Ustrlen(sender_host_address)) == 0;
2921 if (strncmpic(sender_host_address, US"::ffff:", 7) == 0)
2922 helo_verified = Ustrncmp(sender_helo_name + 1,
2923 sender_host_address + 7, Ustrlen(sender_host_address) - 7) == 0;
2928 { if (helo_verified) debug_printf("matched host address\n"); }
2931 /* Do a reverse lookup if one hasn't already given a positive or negative
2932 response. If that fails, or the name doesn't match, try checking with a forward
2937 if (sender_host_name == NULL && !host_lookup_failed)
2938 yield = host_name_lookup() != DEFER;
2940 /* If a host name is known, check it and all its aliases. */
2942 if (sender_host_name != NULL)
2944 helo_verified = strcmpic(sender_host_name, sender_helo_name) == 0;
2948 HDEBUG(D_receive) debug_printf("matched host name\n");
2952 uschar **aliases = sender_host_aliases;
2953 while (*aliases != NULL)
2955 helo_verified = strcmpic(*aliases++, sender_helo_name) == 0;
2956 if (helo_verified) break;
2961 debug_printf("matched alias %s\n", *(--aliases));
2966 /* Final attempt: try a forward lookup of the helo name */
2972 h.name = sender_helo_name;
2976 HDEBUG(D_receive) debug_printf("getting IP address for %s\n",
2978 rc = host_find_byname(&h, NULL, 0, NULL, TRUE);
2979 if (rc == HOST_FOUND || rc == HOST_FOUND_LOCAL)
2984 if (Ustrcmp(hh->address, sender_host_address) == 0)
2986 helo_verified = TRUE;
2988 debug_printf("IP address for %s matches calling address\n",
2998 if (!helo_verified) helo_verify_failed = TRUE; /* We've tried ... */
3005 /*************************************************
3006 * Send user response message *
3007 *************************************************/
3009 /* This function is passed a default response code and a user message. It calls
3010 smtp_message_code() to check and possibly modify the response code, and then
3011 calls smtp_respond() to transmit the response. I put this into a function
3012 just to avoid a lot of repetition.
3015 code the response code
3016 user_msg the user message
3022 smtp_user_msg(uschar *code, uschar *user_msg)
3025 smtp_message_code(&code, &len, &user_msg, NULL);
3026 smtp_respond(code, len, TRUE, user_msg);
3031 /*************************************************
3032 * Initialize for SMTP incoming message *
3033 *************************************************/
3035 /* This function conducts the initial dialogue at the start of an incoming SMTP
3036 message, and builds a list of recipients. However, if the incoming message
3037 is part of a batch (-bS option) a separate function is called since it would
3038 be messy having tests splattered about all over this function. This function
3039 therefore handles the case where interaction is occurring. The input and output
3040 files are set up in smtp_in and smtp_out.
3042 The global recipients_list is set to point to a vector of recipient_item
3043 blocks, whose number is given by recipients_count. This is extended by the
3044 receive_add_recipient() function. The global variable sender_address is set to
3045 the sender's address. The yield is +1 if a message has been successfully
3046 started, 0 if a QUIT command was encountered or the connection was refused from
3047 the particular host, or -1 if the connection was lost.
3051 Returns: > 0 message successfully started (reached DATA)
3052 = 0 QUIT read or end of file reached or call refused
3057 smtp_setup_msg(void)
3060 BOOL toomany = FALSE;
3061 BOOL discarded = FALSE;
3062 BOOL last_was_rej_mail = FALSE;
3063 BOOL last_was_rcpt = FALSE;
3064 void *reset_point = store_get(0);
3066 DEBUG(D_receive) debug_printf("smtp_setup_msg entered\n");
3068 /* Reset for start of new message. We allow one RSET not to be counted as a
3069 nonmail command, for those MTAs that insist on sending it between every
3070 message. Ditto for EHLO/HELO and for STARTTLS, to allow for going in and out of
3071 TLS between messages (an Exim client may do this if it has messages queued up
3072 for the host). Note: we do NOT reset AUTH at this point. */
3074 smtp_reset(reset_point);
3075 message_ended = END_NOTSTARTED;
3077 cmd_list[CMD_LIST_RSET].is_mail_cmd = TRUE;
3078 cmd_list[CMD_LIST_HELO].is_mail_cmd = TRUE;
3079 cmd_list[CMD_LIST_EHLO].is_mail_cmd = TRUE;
3081 cmd_list[CMD_LIST_STARTTLS].is_mail_cmd = TRUE;
3084 /* Set the local signal handler for SIGTERM - it tries to end off tidily */
3086 os_non_restarting_signal(SIGTERM, command_sigterm_handler);
3088 /* Batched SMTP is handled in a different function. */
3090 if (smtp_batched_input) return smtp_setup_batch_msg();
3092 /* Deal with SMTP commands. This loop is exited by setting done to a POSITIVE
3093 value. The values are 2 larger than the required yield of the function. */
3098 uschar *etrn_command;
3099 uschar *etrn_serialize_key;
3101 uschar *log_msg, *smtp_code;
3102 uschar *user_msg = NULL;
3103 uschar *recipient = NULL;
3104 uschar *hello = NULL;
3105 uschar *set_id = NULL;
3107 BOOL was_rej_mail = FALSE;
3108 BOOL was_rcpt = FALSE;
3109 void (*oldsignal)(int);
3111 int start, end, sender_domain, recipient_domain;
3116 switch(smtp_read_command(TRUE))
3118 /* The AUTH command is not permitted to occur inside a transaction, and may
3119 occur successfully only once per connection. Actually, that isn't quite
3120 true. When TLS is started, all previous information about a connection must
3121 be discarded, so a new AUTH is permitted at that time.
3123 AUTH may only be used when it has been advertised. However, it seems that
3124 there are clients that send AUTH when it hasn't been advertised, some of
3125 them even doing this after HELO. And there are MTAs that accept this. Sigh.
3126 So there's a get-out that allows this to happen.
3128 AUTH is initially labelled as a "nonmail command" so that one occurrence
3129 doesn't get counted. We change the label here so that multiple failing
3130 AUTHS will eventually hit the nonmail threshold. */
3134 authentication_failed = TRUE;
3135 cmd_list[CMD_LIST_AUTH].is_mail_cmd = FALSE;
3137 if (!auth_advertised && !allow_auth_unadvertised)
3139 done = synprot_error(L_smtp_protocol_error, 503, NULL,
3140 US"AUTH command used when not advertised");
3143 if (sender_host_authenticated != NULL)
3145 done = synprot_error(L_smtp_protocol_error, 503, NULL,
3146 US"already authenticated");
3149 if (sender_address != NULL)
3151 done = synprot_error(L_smtp_protocol_error, 503, NULL,
3152 US"not permitted in mail transaction");
3158 if (acl_smtp_auth != NULL)
3160 rc = acl_check(ACL_WHERE_AUTH, NULL, acl_smtp_auth, &user_msg, &log_msg);
3163 done = smtp_handle_acl_fail(ACL_WHERE_AUTH, rc, user_msg, log_msg);
3168 /* Find the name of the requested authentication mechanism. */
3171 while ((c = *smtp_cmd_data) != 0 && !isspace(c))
3173 if (!isalnum(c) && c != '-' && c != '_')
3175 done = synprot_error(L_smtp_syntax_error, 501, NULL,
3176 US"invalid character in authentication mechanism name");
3182 /* If not at the end of the line, we must be at white space. Terminate the
3183 name and move the pointer on to any data that may be present. */
3185 if (*smtp_cmd_data != 0)
3187 *smtp_cmd_data++ = 0;
3188 while (isspace(*smtp_cmd_data)) smtp_cmd_data++;
3191 /* Search for an authentication mechanism which is configured for use
3192 as a server and which has been advertised (unless, sigh, allow_auth_
3193 unadvertised is set). */
3195 for (au = auths; au != NULL; au = au->next)
3197 if (strcmpic(s, au->public_name) == 0 && au->server &&
3198 (au->advertised || allow_auth_unadvertised)) break;
3203 done = synprot_error(L_smtp_protocol_error, 504, NULL,
3204 string_sprintf("%s authentication mechanism not supported", s));
3208 /* Run the checking code, passing the remainder of the command line as
3209 data. Initials the $auth<n> variables as empty. Initialize $0 empty and set
3210 it as the only set numerical variable. The authenticator may set $auth<n>
3211 and also set other numeric variables. The $auth<n> variables are preferred
3212 nowadays; the numerical variables remain for backwards compatibility.
3214 Afterwards, have a go at expanding the set_id string, even if
3215 authentication failed - for bad passwords it can be useful to log the
3216 userid. On success, require set_id to expand and exist, and put it in
3217 authenticated_id. Save this in permanent store, as the working store gets
3218 reset at HELO, RSET, etc. */
3220 for (i = 0; i < AUTH_VARS; i++) auth_vars[i] = NULL;
3222 expand_nlength[0] = 0; /* $0 contains nothing */
3224 c = (au->info->servercode)(au, smtp_cmd_data);
3225 if (au->set_id != NULL) set_id = expand_string(au->set_id);
3226 expand_nmax = -1; /* Reset numeric variables */
3227 for (i = 0; i < AUTH_VARS; i++) auth_vars[i] = NULL; /* Reset $auth<n> */
3229 /* The value of authenticated_id is stored in the spool file and printed in
3230 log lines. It must not contain binary zeros or newline characters. In
3231 normal use, it never will, but when playing around or testing, this error
3232 can (did) happen. To guard against this, ensure that the id contains only
3233 printing characters. */
3235 if (set_id != NULL) set_id = string_printing(set_id);
3237 /* For the non-OK cases, set up additional logging data if set_id
3242 if (set_id != NULL && *set_id != 0)
3243 set_id = string_sprintf(" (set_id=%s)", set_id);
3247 /* Switch on the result */
3252 if (au->set_id == NULL || set_id != NULL) /* Complete success */
3254 if (set_id != NULL) authenticated_id = string_copy_malloc(set_id);
3255 sender_host_authenticated = au->name;
3256 authentication_failed = FALSE;
3257 authenticated_fail_id = NULL; /* Impossible to already be set? */
3259 protocols[pextend + pauthed + ((tls_in.active >= 0)? pcrpted:0)] +
3260 ((sender_host_address != NULL)? pnlocal : 0);
3261 s = ss = US"235 Authentication succeeded";
3262 authenticated_by = au;
3266 /* Authentication succeeded, but we failed to expand the set_id string.
3267 Treat this as a temporary error. */
3269 auth_defer_msg = expand_string_message;
3273 if (set_id != NULL) authenticated_fail_id = string_copy_malloc(set_id);
3274 s = string_sprintf("435 Unable to authenticate at present%s",
3275 auth_defer_user_msg);
3276 ss = string_sprintf("435 Unable to authenticate at present%s: %s",
3277 set_id, auth_defer_msg);
3281 s = ss = US"501 Invalid base64 data";
3285 s = ss = US"501 Authentication cancelled";
3289 s = ss = US"553 Initial data not expected";
3293 if (set_id != NULL) authenticated_fail_id = string_copy_malloc(set_id);
3294 s = US"535 Incorrect authentication data";
3295 ss = string_sprintf("535 Incorrect authentication data%s", set_id);
3299 if (set_id != NULL) authenticated_fail_id = string_copy_malloc(set_id);
3300 s = US"435 Internal error";
3301 ss = string_sprintf("435 Internal error%s: return %d from authentication "
3302 "check", set_id, c);
3306 smtp_printf("%s\r\n", s);
3308 log_write(0, LOG_MAIN|LOG_REJECT, "%s authenticator failed for %s: %s",
3309 au->name, host_and_ident(FALSE), ss);
3311 break; /* AUTH_CMD */
3313 /* The HELO/EHLO commands are permitted to appear in the middle of a
3314 session as well as at the beginning. They have the effect of a reset in
3315 addition to their other functions. Their absence at the start cannot be
3316 taken to be an error.
3320 If the EHLO command is not acceptable to the SMTP server, 501, 500,
3321 or 502 failure replies MUST be returned as appropriate. The SMTP
3322 server MUST stay in the same state after transmitting these replies
3323 that it was in before the EHLO was received.
3325 Therefore, we do not do the reset until after checking the command for
3326 acceptability. This change was made for Exim release 4.11. Previously
3327 it did the reset first. */
3340 HELO_EHLO: /* Common code for HELO and EHLO */
3341 cmd_list[CMD_LIST_HELO].is_mail_cmd = FALSE;
3342 cmd_list[CMD_LIST_EHLO].is_mail_cmd = FALSE;
3344 /* Reject the HELO if its argument was invalid or non-existent. A
3345 successful check causes the argument to be saved in malloc store. */
3347 if (!check_helo(smtp_cmd_data))
3349 smtp_printf("501 Syntactically invalid %s argument(s)\r\n", hello);
3351 log_write(0, LOG_MAIN|LOG_REJECT, "rejected %s from %s: syntactically "
3352 "invalid argument(s): %s", hello, host_and_ident(FALSE),
3353 (*smtp_cmd_argument == 0)? US"(no argument given)" :
3354 string_printing(smtp_cmd_argument));
3356 if (++synprot_error_count > smtp_max_synprot_errors)
3358 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
3359 "syntax or protocol errors (last command was \"%s\")",
3360 host_and_ident(FALSE), smtp_cmd_buffer);
3367 /* If sender_host_unknown is true, we have got here via the -bs interface,
3368 not called from inetd. Otherwise, we are running an IP connection and the
3369 host address will be set. If the helo name is the primary name of this
3370 host and we haven't done a reverse lookup, force one now. If helo_required
3371 is set, ensure that the HELO name matches the actual host. If helo_verify
3372 is set, do the same check, but softly. */
3374 if (!sender_host_unknown)
3376 BOOL old_helo_verified = helo_verified;
3377 uschar *p = smtp_cmd_data;
3379 while (*p != 0 && !isspace(*p)) { *p = tolower(*p); p++; }
3382 /* Force a reverse lookup if HELO quoted something in helo_lookup_domains
3383 because otherwise the log can be confusing. */
3385 if (sender_host_name == NULL &&
3386 (deliver_domain = sender_helo_name, /* set $domain */
3387 match_isinlist(sender_helo_name, &helo_lookup_domains, 0,
3388 &domainlist_anchor, NULL, MCL_DOMAIN, TRUE, NULL)) == OK)
3389 (void)host_name_lookup();
3391 /* Rebuild the fullhost info to include the HELO name (and the real name
3392 if it was looked up.) */
3394 host_build_sender_fullhost(); /* Rebuild */
3395 set_process_info("handling%s incoming connection from %s",
3396 (tls_in.active >= 0)? " TLS" : "", host_and_ident(FALSE));
3398 /* Verify if configured. This doesn't give much security, but it does
3399 make some people happy to be able to do it. If helo_required is set,
3400 (host matches helo_verify_hosts) failure forces rejection. If helo_verify
3401 is set (host matches helo_try_verify_hosts), it does not. This is perhaps
3402 now obsolescent, since the verification can now be requested selectively
3405 helo_verified = helo_verify_failed = FALSE;
3406 if (helo_required || helo_verify)
3408 BOOL tempfail = !smtp_verify_helo();
3413 smtp_printf("%d %s argument does not match calling host\r\n",
3414 tempfail? 451 : 550, hello);
3415 log_write(0, LOG_MAIN|LOG_REJECT, "%srejected \"%s %s\" from %s",
3416 tempfail? "temporarily " : "",
3417 hello, sender_helo_name, host_and_ident(FALSE));
3418 helo_verified = old_helo_verified;
3419 break; /* End of HELO/EHLO processing */
3421 HDEBUG(D_all) debug_printf("%s verification failed but host is in "
3422 "helo_try_verify_hosts\n", hello);
3427 #ifdef EXPERIMENTAL_SPF
3428 /* set up SPF context */
3429 spf_init(sender_helo_name, sender_host_address);
3432 /* Apply an ACL check if one is defined; afterwards, recheck
3433 synchronization in case the client started sending in a delay. */
3435 if (acl_smtp_helo != NULL)
3437 rc = acl_check(ACL_WHERE_HELO, NULL, acl_smtp_helo, &user_msg, &log_msg);
3440 done = smtp_handle_acl_fail(ACL_WHERE_HELO, rc, user_msg, log_msg);
3441 sender_helo_name = NULL;
3442 host_build_sender_fullhost(); /* Rebuild */
3445 else if (!check_sync()) goto SYNC_FAILURE;
3448 /* Generate an OK reply. The default string includes the ident if present,
3449 and also the IP address if present. Reflecting back the ident is intended
3450 as a deterrent to mail forgers. For maximum efficiency, and also because
3451 some broken systems expect each response to be in a single packet, arrange
3452 that the entire reply is sent in one write(). */
3454 auth_advertised = FALSE;
3455 pipelining_advertised = FALSE;
3457 tls_advertised = FALSE;
3460 smtp_code = US"250 "; /* Default response code plus space*/
3461 if (user_msg == NULL)
3463 s = string_sprintf("%.3s %s Hello %s%s%s",
3465 smtp_active_hostname,
3466 (sender_ident == NULL)? US"" : sender_ident,
3467 (sender_ident == NULL)? US"" : US" at ",
3468 (sender_host_name == NULL)? sender_helo_name : sender_host_name);
3473 if (sender_host_address != NULL)
3475 s = string_cat(s, &size, &ptr, US" [", 2);
3476 s = string_cat(s, &size, &ptr, sender_host_address,
3477 Ustrlen(sender_host_address));
3478 s = string_cat(s, &size, &ptr, US"]", 1);
3482 /* A user-supplied EHLO greeting may not contain more than one line. Note
3483 that the code returned by smtp_message_code() includes the terminating
3484 whitespace character. */
3490 smtp_message_code(&smtp_code, &codelen, &user_msg, NULL);
3491 s = string_sprintf("%.*s%s", codelen, smtp_code, user_msg);
3492 if ((ss = strpbrk(CS s, "\r\n")) != NULL)
3494 log_write(0, LOG_MAIN|LOG_PANIC, "EHLO/HELO response must not contain "
3495 "newlines: message truncated: %s", string_printing(s));
3502 s = string_cat(s, &size, &ptr, US"\r\n", 2);
3504 /* If we received EHLO, we must create a multiline response which includes
3505 the functions supported. */
3511 /* I'm not entirely happy with this, as an MTA is supposed to check
3512 that it has enough room to accept a message of maximum size before
3513 it sends this. However, there seems little point in not sending it.
3514 The actual size check happens later at MAIL FROM time. By postponing it
3515 till then, VRFY and EXPN can be used after EHLO when space is short. */
3517 if (thismessage_size_limit > 0)
3519 sprintf(CS big_buffer, "%.3s-SIZE %d\r\n", smtp_code,
3520 thismessage_size_limit);
3521 s = string_cat(s, &size, &ptr, big_buffer, Ustrlen(big_buffer));
3525 s = string_cat(s, &size, &ptr, smtp_code, 3);
3526 s = string_cat(s, &size, &ptr, US"-SIZE\r\n", 7);
3529 /* Exim does not do protocol conversion or data conversion. It is 8-bit
3530 clean; if it has an 8-bit character in its hand, it just sends it. It
3531 cannot therefore specify 8BITMIME and remain consistent with the RFCs.
3532 However, some users want this option simply in order to stop MUAs
3533 mangling messages that contain top-bit-set characters. It is therefore
3534 provided as an option. */
3536 if (accept_8bitmime)
3538 s = string_cat(s, &size, &ptr, smtp_code, 3);
3539 s = string_cat(s, &size, &ptr, US"-8BITMIME\r\n", 11);
3542 /* Advertise ETRN if there's an ACL checking whether a host is
3543 permitted to issue it; a check is made when any host actually tries. */
3545 if (acl_smtp_etrn != NULL)
3547 s = string_cat(s, &size, &ptr, smtp_code, 3);
3548 s = string_cat(s, &size, &ptr, US"-ETRN\r\n", 7);
3551 /* Advertise EXPN if there's an ACL checking whether a host is
3552 permitted to issue it; a check is made when any host actually tries. */
3554 if (acl_smtp_expn != NULL)
3556 s = string_cat(s, &size, &ptr, smtp_code, 3);
3557 s = string_cat(s, &size, &ptr, US"-EXPN\r\n", 7);
3560 /* Exim is quite happy with pipelining, so let the other end know that
3561 it is safe to use it, unless advertising is disabled. */
3563 if (pipelining_enable &&
3564 verify_check_host(&pipelining_advertise_hosts) == OK)
3566 s = string_cat(s, &size, &ptr, smtp_code, 3);
3567 s = string_cat(s, &size, &ptr, US"-PIPELINING\r\n", 13);
3568 sync_cmd_limit = NON_SYNC_CMD_PIPELINING;
3569 pipelining_advertised = TRUE;
3573 /* If any server authentication mechanisms are configured, advertise
3574 them if the current host is in auth_advertise_hosts. The problem with
3575 advertising always is that some clients then require users to
3576 authenticate (and aren't configurable otherwise) even though it may not
3577 be necessary (e.g. if the host is in host_accept_relay).
3579 RFC 2222 states that SASL mechanism names contain only upper case
3580 letters, so output the names in upper case, though we actually recognize
3581 them in either case in the AUTH command. */
3585 if (verify_check_host(&auth_advertise_hosts) == OK)
3589 for (au = auths; au != NULL; au = au->next)
3591 if (au->server && (au->advertise_condition == NULL ||
3592 expand_check_condition(au->advertise_condition, au->name,
3593 US"authenticator")))
3598 s = string_cat(s, &size, &ptr, smtp_code, 3);
3599 s = string_cat(s, &size, &ptr, US"-AUTH", 5);
3601 auth_advertised = TRUE;
3604 s = string_cat(s, &size, &ptr, US" ", 1);
3605 s = string_cat(s, &size, &ptr, au->public_name,
3606 Ustrlen(au->public_name));
3607 while (++saveptr < ptr) s[saveptr] = toupper(s[saveptr]);
3608 au->advertised = TRUE;
3610 else au->advertised = FALSE;
3612 if (!first) s = string_cat(s, &size, &ptr, US"\r\n", 2);
3616 /* Advertise TLS (Transport Level Security) aka SSL (Secure Socket Layer)
3617 if it has been included in the binary, and the host matches
3618 tls_advertise_hosts. We must *not* advertise if we are already in a
3619 secure connection. */
3622 if (tls_in.active < 0 &&
3623 verify_check_host(&tls_advertise_hosts) != FAIL)
3625 s = string_cat(s, &size, &ptr, smtp_code, 3);
3626 s = string_cat(s, &size, &ptr, US"-STARTTLS\r\n", 11);
3627 tls_advertised = TRUE;
3631 #ifdef EXPERIMENTAL_PRDR
3632 /* Per Recipient Data Response, draft by Eric A. Hall extending RFC */
3634 s = string_cat(s, &size, &ptr, smtp_code, 3);
3635 s = string_cat(s, &size, &ptr, US"-PRDR\r\n", 7);
3639 /* Finish off the multiline reply with one that is always available. */
3641 s = string_cat(s, &size, &ptr, smtp_code, 3);
3642 s = string_cat(s, &size, &ptr, US" HELP\r\n", 7);
3645 /* Terminate the string (for debug), write it, and note that HELO/EHLO
3651 if (tls_in.active >= 0) (void)tls_write(TRUE, s, ptr); else
3655 int i = fwrite(s, 1, ptr, smtp_out); i = i; /* compiler quietening */
3660 while ((cr = Ustrchr(s, '\r')) != NULL) /* lose CRs */
3661 memmove(cr, cr + 1, (ptr--) - (cr - s));
3662 debug_printf("SMTP>> %s", s);
3666 /* Reset the protocol and the state, abandoning any previous message. */
3668 received_protocol = (esmtp?
3670 ((sender_host_authenticated != NULL)? pauthed : 0) +
3671 ((tls_in.active >= 0)? pcrpted : 0)]
3673 protocols[pnormal + ((tls_in.active >= 0)? pcrpted : 0)])
3675 ((sender_host_address != NULL)? pnlocal : 0);
3677 smtp_reset(reset_point);
3679 break; /* HELO/EHLO */
3682 /* The MAIL command requires an address as an operand. All we do
3683 here is to parse it for syntactic correctness. The form "<>" is
3684 a special case which converts into an empty string. The start/end
3685 pointers in the original are not used further for this address, as
3686 it is the canonical extracted address which is all that is kept. */
3690 smtp_mailcmd_count++; /* Count for limit and ratelimit */
3691 was_rej_mail = TRUE; /* Reset if accepted */
3692 env_mail_type_t * mail_args; /* Sanity check & validate args */
3694 if (helo_required && !helo_seen)
3696 smtp_printf("503 HELO or EHLO required\r\n");
3697 log_write(0, LOG_MAIN|LOG_REJECT, "rejected MAIL from %s: no "
3698 "HELO/EHLO given", host_and_ident(FALSE));
3702 if (sender_address != NULL)
3704 done = synprot_error(L_smtp_protocol_error, 503, NULL,
3705 US"sender already given");
3709 if (smtp_cmd_data[0] == 0)
3711 done = synprot_error(L_smtp_protocol_error, 501, NULL,
3712 US"MAIL must have an address operand");
3716 /* Check to see if the limit for messages per connection would be
3717 exceeded by accepting further messages. */
3719 if (smtp_accept_max_per_connection > 0 &&
3720 smtp_mailcmd_count > smtp_accept_max_per_connection)
3722 smtp_printf("421 too many messages in this connection\r\n");
3723 log_write(0, LOG_MAIN|LOG_REJECT, "rejected MAIL command %s: too many "
3724 "messages in one connection", host_and_ident(TRUE));
3728 /* Reset for start of message - even if this is going to fail, we
3729 obviously need to throw away any previous data. */
3731 smtp_reset(reset_point);
3733 sender_data = recipient_data = NULL;
3735 /* Loop, checking for ESMTP additions to the MAIL FROM command. */
3739 uschar *name, *value, *end;
3740 unsigned long int size;
3741 BOOL arg_error = FALSE;
3743 if (!extract_option(&name, &value)) break;
3745 for (mail_args = env_mail_type_list;
3746 (char *)mail_args < (char *)env_mail_type_list + sizeof(env_mail_type_list);
3750 if (strcmpic(name, mail_args->name) == 0)
3753 if (mail_args->need_value && strcmpic(value, US"") == 0)
3756 switch(mail_args->value)
3758 /* Handle SIZE= by reading the value. We don't do the check till later,
3759 in order to be able to log the sender address on failure. */
3760 case ENV_MAIL_OPT_SIZE:
3761 if (((size = Ustrtoul(value, &end, 10)), *end == 0))
3763 if ((size == ULONG_MAX && errno == ERANGE) || size > INT_MAX)
3765 message_size = (int)size;
3771 /* If this session was initiated with EHLO and accept_8bitmime is set,
3772 Exim will have indicated that it supports the BODY=8BITMIME option. In
3773 fact, it does not support this according to the RFCs, in that it does not
3774 take any special action for forwarding messages containing 8-bit
3775 characters. That is why accept_8bitmime is not the default setting, but
3776 some sites want the action that is provided. We recognize both "8BITMIME"
3777 and "7BIT" as body types, but take no action. */
3778 case ENV_MAIL_OPT_BODY:
3779 if (accept_8bitmime) {
3780 if (strcmpic(value, US"8BITMIME") == 0) {
3782 } else if (strcmpic(value, US"7BIT") == 0) {
3786 done = synprot_error(L_smtp_syntax_error, 501, NULL,
3787 US"invalid data for BODY");
3790 DEBUG(D_receive) debug_printf("8BITMIME: %d\n", body_8bitmime);
3796 /* Handle the AUTH extension. If the value given is not "<>" and either
3797 the ACL says "yes" or there is no ACL but the sending host is
3798 authenticated, we set it up as the authenticated sender. However, if the
3799 authenticator set a condition to be tested, we ignore AUTH on MAIL unless
3800 the condition is met. The value of AUTH is an xtext, which means that +,
3801 = and cntrl chars are coded in hex; however "<>" is unaffected by this
3803 case ENV_MAIL_OPT_AUTH:
3804 if (Ustrcmp(value, "<>") != 0)
3809 if (auth_xtextdecode(value, &authenticated_sender) < 0)
3811 /* Put back terminator overrides for error message */
3814 done = synprot_error(L_smtp_syntax_error, 501, NULL,
3815 US"invalid data for AUTH");
3818 if (acl_smtp_mailauth == NULL)
3820 ignore_msg = US"client not authenticated";
3821 rc = (sender_host_authenticated != NULL)? OK : FAIL;
3825 ignore_msg = US"rejected by ACL";
3826 rc = acl_check(ACL_WHERE_MAILAUTH, NULL, acl_smtp_mailauth,
3827 &user_msg, &log_msg);
3833 if (authenticated_by == NULL ||
3834 authenticated_by->mail_auth_condition == NULL ||
3835 expand_check_condition(authenticated_by->mail_auth_condition,
3836 authenticated_by->name, US"authenticator"))
3837 break; /* Accept the AUTH */
3839 ignore_msg = US"server_mail_auth_condition failed";
3840 if (authenticated_id != NULL)
3841 ignore_msg = string_sprintf("%s: authenticated ID=\"%s\"",
3842 ignore_msg, authenticated_id);
3847 authenticated_sender = NULL;
3848 log_write(0, LOG_MAIN, "ignoring AUTH=%s from %s (%s)",
3849 value, host_and_ident(TRUE), ignore_msg);
3852 /* Should only get DEFER or ERROR here. Put back terminator
3853 overrides for error message */
3858 (void)smtp_handle_acl_fail(ACL_WHERE_MAILAUTH, rc, user_msg,
3865 #ifdef EXPERIMENTAL_PRDR
3866 case ENV_MAIL_OPT_PRDR:
3868 prdr_requested = TRUE;
3872 /* Unknown option. Stick back the terminator characters and break
3873 the loop. Do the name-terminator second as extract_option sets
3874 value==name when it found no equal-sign.
3875 An error for a malformed address will occur. */
3882 /* Break out of for loop if switch() had bad argument or
3883 when start of the email address is reached */
3884 if (arg_error) break;
3887 /* If we have passed the threshold for rate limiting, apply the current
3888 delay, and update it for next time, provided this is a limited host. */
3890 if (smtp_mailcmd_count > smtp_rlm_threshold &&
3891 verify_check_host(&smtp_ratelimit_hosts) == OK)
3893 DEBUG(D_receive) debug_printf("rate limit MAIL: delay %.3g sec\n",
3894 smtp_delay_mail/1000.0);
3895 millisleep((int)smtp_delay_mail);
3896 smtp_delay_mail *= smtp_rlm_factor;
3897 if (smtp_delay_mail > (double)smtp_rlm_limit)
3898 smtp_delay_mail = (double)smtp_rlm_limit;
3901 /* Now extract the address, first applying any SMTP-time rewriting. The
3902 TRUE flag allows "<>" as a sender address. */
3904 raw_sender = ((rewrite_existflags & rewrite_smtp) != 0)?
3905 rewrite_one(smtp_cmd_data, rewrite_smtp, NULL, FALSE, US"",
3906 global_rewrite_rules) : smtp_cmd_data;
3908 /* rfc821_domains = TRUE; << no longer needed */
3910 parse_extract_address(raw_sender, &errmess, &start, &end, &sender_domain,
3912 /* rfc821_domains = FALSE; << no longer needed */
3914 if (raw_sender == NULL)
3916 done = synprot_error(L_smtp_syntax_error, 501, smtp_cmd_data, errmess);
3920 sender_address = raw_sender;
3922 /* If there is a configured size limit for mail, check that this message
3923 doesn't exceed it. The check is postponed to this point so that the sender
3926 if (thismessage_size_limit > 0 && message_size > thismessage_size_limit)
3928 smtp_printf("552 Message size exceeds maximum permitted\r\n");
3929 log_write(L_size_reject,
3930 LOG_MAIN|LOG_REJECT, "rejected MAIL FROM:<%s> %s: "
3931 "message too big: size%s=%d max=%d",
3933 host_and_ident(TRUE),
3934 (message_size == INT_MAX)? ">" : "",
3936 thismessage_size_limit);
3937 sender_address = NULL;
3941 /* Check there is enough space on the disk unless configured not to.
3942 When smtp_check_spool_space is set, the check is for thismessage_size_limit
3943 plus the current message - i.e. we accept the message only if it won't
3944 reduce the space below the threshold. Add 5000 to the size to allow for
3945 overheads such as the Received: line and storing of recipients, etc.
3946 By putting the check here, even when SIZE is not given, it allow VRFY
3947 and EXPN etc. to be used when space is short. */
3949 if (!receive_check_fs(
3950 (smtp_check_spool_space && message_size >= 0)?
3951 message_size + 5000 : 0))
3953 smtp_printf("452 Space shortage, please try later\r\n");
3954 sender_address = NULL;
3958 /* If sender_address is unqualified, reject it, unless this is a locally
3959 generated message, or the sending host or net is permitted to send
3960 unqualified addresses - typically local machines behaving as MUAs -
3961 in which case just qualify the address. The flag is set above at the start
3962 of the SMTP connection. */
3964 if (sender_domain == 0 && sender_address[0] != 0)
3966 if (allow_unqualified_sender)
3968 sender_domain = Ustrlen(sender_address) + 1;
3969 sender_address = rewrite_address_qualify(sender_address, FALSE);
3970 DEBUG(D_receive) debug_printf("unqualified address %s accepted\n",
3975 smtp_printf("501 %s: sender address must contain a domain\r\n",
3977 log_write(L_smtp_syntax_error,
3978 LOG_MAIN|LOG_REJECT,
3979 "unqualified sender rejected: <%s> %s%s",
3981 host_and_ident(TRUE),
3983 sender_address = NULL;
3988 /* Apply an ACL check if one is defined, before responding. Afterwards,
3989 when pipelining is not advertised, do another sync check in case the ACL
3990 delayed and the client started sending in the meantime. */
3992 if (acl_smtp_mail == NULL) rc = OK; else
3994 rc = acl_check(ACL_WHERE_MAIL, NULL, acl_smtp_mail, &user_msg, &log_msg);
3995 if (rc == OK && !pipelining_advertised && !check_sync())
3999 if (rc == OK || rc == DISCARD)
4001 if (user_msg == NULL)
4002 smtp_printf("%s%s%s", US"250 OK",
4003 #ifdef EXPERIMENTAL_PRDR
4004 prdr_requested == TRUE ? US", PRDR Requested" :
4010 #ifdef EXPERIMENTAL_PRDR
4011 if ( prdr_requested == TRUE )
4012 user_msg = string_sprintf("%s%s", user_msg, US", PRDR Requested");
4014 smtp_user_msg(US"250",user_msg);
4016 smtp_delay_rcpt = smtp_rlr_base;
4017 recipients_discarded = (rc == DISCARD);
4018 was_rej_mail = FALSE;
4022 done = smtp_handle_acl_fail(ACL_WHERE_MAIL, rc, user_msg, log_msg);
4023 sender_address = NULL;
4028 /* The RCPT command requires an address as an operand. There may be any
4029 number of RCPT commands, specifying multiple recipients. We build them all
4030 into a data structure. The start/end values given by parse_extract_address
4031 are not used, as we keep only the extracted address. */
4036 was_rcpt = rcpt_in_progress = TRUE;
4038 /* There must be a sender address; if the sender was rejected and
4039 pipelining was advertised, we assume the client was pipelining, and do not
4040 count this as a protocol error. Reset was_rej_mail so that further RCPTs
4041 get the same treatment. */
4043 if (sender_address == NULL)
4045 if (pipelining_advertised && last_was_rej_mail)
4047 smtp_printf("503 sender not yet given\r\n");
4048 was_rej_mail = TRUE;
4052 done = synprot_error(L_smtp_protocol_error, 503, NULL,
4053 US"sender not yet given");
4054 was_rcpt = FALSE; /* Not a valid RCPT */
4060 /* Check for an operand */
4062 if (smtp_cmd_data[0] == 0)
4064 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4065 US"RCPT must have an address operand");
4070 /* Apply SMTP rewriting then extract the working address. Don't allow "<>"
4071 as a recipient address */
4073 recipient = ((rewrite_existflags & rewrite_smtp) != 0)?
4074 rewrite_one(smtp_cmd_data, rewrite_smtp, NULL, FALSE, US"",
4075 global_rewrite_rules) : smtp_cmd_data;
4077 /* rfc821_domains = TRUE; << no longer needed */
4078 recipient = parse_extract_address(recipient, &errmess, &start, &end,
4079 &recipient_domain, FALSE);
4080 /* rfc821_domains = FALSE; << no longer needed */
4082 if (recipient == NULL)
4084 done = synprot_error(L_smtp_syntax_error, 501, smtp_cmd_data, errmess);
4089 /* If the recipient address is unqualified, reject it, unless this is a
4090 locally generated message. However, unqualified addresses are permitted
4091 from a configured list of hosts and nets - typically when behaving as
4092 MUAs rather than MTAs. Sad that SMTP is used for both types of traffic,
4093 really. The flag is set at the start of the SMTP connection.
4095 RFC 1123 talks about supporting "the reserved mailbox postmaster"; I always
4096 assumed this meant "reserved local part", but the revision of RFC 821 and
4097 friends now makes it absolutely clear that it means *mailbox*. Consequently
4098 we must always qualify this address, regardless. */
4100 if (recipient_domain == 0)
4102 if (allow_unqualified_recipient ||
4103 strcmpic(recipient, US"postmaster") == 0)
4105 DEBUG(D_receive) debug_printf("unqualified address %s accepted\n",
4107 recipient_domain = Ustrlen(recipient) + 1;
4108 recipient = rewrite_address_qualify(recipient, TRUE);
4113 smtp_printf("501 %s: recipient address must contain a domain\r\n",
4115 log_write(L_smtp_syntax_error,
4116 LOG_MAIN|LOG_REJECT, "unqualified recipient rejected: "
4117 "<%s> %s%s", recipient, host_and_ident(TRUE),
4123 /* Check maximum allowed */
4125 if (rcpt_count > recipients_max && recipients_max > 0)
4127 if (recipients_max_reject)
4130 smtp_printf("552 too many recipients\r\n");
4132 log_write(0, LOG_MAIN|LOG_REJECT, "too many recipients: message "
4133 "rejected: sender=<%s> %s", sender_address, host_and_ident(TRUE));
4138 smtp_printf("452 too many recipients\r\n");
4140 log_write(0, LOG_MAIN|LOG_REJECT, "too many recipients: excess "
4141 "temporarily rejected: sender=<%s> %s", sender_address,
4142 host_and_ident(TRUE));
4149 /* If we have passed the threshold for rate limiting, apply the current
4150 delay, and update it for next time, provided this is a limited host. */
4152 if (rcpt_count > smtp_rlr_threshold &&
4153 verify_check_host(&smtp_ratelimit_hosts) == OK)
4155 DEBUG(D_receive) debug_printf("rate limit RCPT: delay %.3g sec\n",
4156 smtp_delay_rcpt/1000.0);
4157 millisleep((int)smtp_delay_rcpt);
4158 smtp_delay_rcpt *= smtp_rlr_factor;
4159 if (smtp_delay_rcpt > (double)smtp_rlr_limit)
4160 smtp_delay_rcpt = (double)smtp_rlr_limit;
4163 /* If the MAIL ACL discarded all the recipients, we bypass ACL checking
4164 for them. Otherwise, check the access control list for this recipient. As
4165 there may be a delay in this, re-check for a synchronization error
4166 afterwards, unless pipelining was advertised. */
4168 if (recipients_discarded) rc = DISCARD; else
4170 rc = acl_check(ACL_WHERE_RCPT, recipient, acl_smtp_rcpt, &user_msg,
4172 if (rc == OK && !pipelining_advertised && !check_sync())
4176 /* The ACL was happy */
4180 if (user_msg == NULL) smtp_printf("250 Accepted\r\n");
4181 else smtp_user_msg(US"250", user_msg);
4182 receive_add_recipient(recipient, -1);
4185 /* The recipient was discarded */
4187 else if (rc == DISCARD)
4189 if (user_msg == NULL) smtp_printf("250 Accepted\r\n");
4190 else smtp_user_msg(US"250", user_msg);
4193 log_write(0, LOG_MAIN|LOG_REJECT, "%s F=<%s> rejected RCPT %s: "
4194 "discarded by %s ACL%s%s", host_and_ident(TRUE),
4195 (sender_address_unrewritten != NULL)?
4196 sender_address_unrewritten : sender_address,
4197 smtp_cmd_argument, recipients_discarded? "MAIL" : "RCPT",
4198 (log_msg == NULL)? US"" : US": ",
4199 (log_msg == NULL)? US"" : log_msg);
4202 /* Either the ACL failed the address, or it was deferred. */
4206 if (rc == FAIL) rcpt_fail_count++; else rcpt_defer_count++;
4207 done = smtp_handle_acl_fail(ACL_WHERE_RCPT, rc, user_msg, log_msg);
4212 /* The DATA command is legal only if it follows successful MAIL FROM
4213 and RCPT TO commands. However, if pipelining is advertised, a bad DATA is
4214 not counted as a protocol error if it follows RCPT (which must have been
4215 rejected if there are no recipients.) This function is complete when a
4216 valid DATA command is encountered.
4218 Note concerning the code used: RFC 2821 says this:
4220 - If there was no MAIL, or no RCPT, command, or all such commands
4221 were rejected, the server MAY return a "command out of sequence"
4222 (503) or "no valid recipients" (554) reply in response to the
4225 The example in the pipelining RFC 2920 uses 554, but I use 503 here
4226 because it is the same whether pipelining is in use or not.
4228 If all the RCPT commands that precede DATA provoked the same error message
4229 (often indicating some kind of system error), it is helpful to include it
4230 with the DATA rejection (an idea suggested by Tony Finch). */
4234 if (!discarded && recipients_count <= 0)
4236 if (rcpt_smtp_response_same && rcpt_smtp_response != NULL)
4238 uschar *code = US"503";
4239 int len = Ustrlen(rcpt_smtp_response);
4240 smtp_respond(code, 3, FALSE, US"All RCPT commands were rejected with "
4242 /* Responses from smtp_printf() will have \r\n on the end */
4243 if (len > 2 && rcpt_smtp_response[len-2] == '\r')
4244 rcpt_smtp_response[len-2] = 0;
4245 smtp_respond(code, 3, FALSE, rcpt_smtp_response);
4247 if (pipelining_advertised && last_was_rcpt)
4248 smtp_printf("503 Valid RCPT command must precede DATA\r\n");
4250 done = synprot_error(L_smtp_protocol_error, 503, NULL,
4251 US"valid RCPT command must precede DATA");
4255 if (toomany && recipients_max_reject)
4257 sender_address = NULL; /* This will allow a new MAIL without RSET */
4258 sender_address_unrewritten = NULL;
4259 smtp_printf("554 Too many recipients\r\n");
4263 /* If there is an ACL, re-check the synchronization afterwards, since the
4264 ACL may have delayed. To handle cutthrough delivery enforce a dummy call
4265 to get the DATA command sent. */
4267 if (acl_smtp_predata == NULL && cutthrough_fd < 0) rc = OK; else
4269 uschar * acl= acl_smtp_predata ? acl_smtp_predata : US"accept";
4270 enable_dollar_recipients = TRUE;
4271 rc = acl_check(ACL_WHERE_PREDATA, NULL, acl, &user_msg,
4273 enable_dollar_recipients = FALSE;
4274 if (rc == OK && !check_sync()) goto SYNC_FAILURE;
4281 if (user_msg == NULL)
4282 smtp_printf("%s Enter message, ending with \".\" on a line by itself\r\n", code);
4283 else smtp_user_msg(code, user_msg);
4285 message_ended = END_NOTENDED; /* Indicate in middle of data */
4288 /* Either the ACL failed the address, or it was deferred. */
4291 done = smtp_handle_acl_fail(ACL_WHERE_PREDATA, rc, user_msg, log_msg);
4297 rc = acl_check(ACL_WHERE_VRFY, NULL, acl_smtp_vrfy, &user_msg, &log_msg);
4299 done = smtp_handle_acl_fail(ACL_WHERE_VRFY, rc, user_msg, log_msg);
4305 /* rfc821_domains = TRUE; << no longer needed */
4306 address = parse_extract_address(smtp_cmd_data, &errmess, &start, &end,
4307 &recipient_domain, FALSE);
4308 /* rfc821_domains = FALSE; << no longer needed */
4310 if (address == NULL)
4311 s = string_sprintf("501 %s", errmess);
4314 address_item *addr = deliver_make_addr(address, FALSE);
4315 switch(verify_address(addr, NULL, vopt_is_recipient | vopt_qualify, -1,
4316 -1, -1, NULL, NULL, NULL))
4319 s = string_sprintf("250 <%s> is deliverable", address);
4323 s = (addr->user_message != NULL)?
4324 string_sprintf("451 <%s> %s", address, addr->user_message) :
4325 string_sprintf("451 Cannot resolve <%s> at this time", address);
4329 s = (addr->user_message != NULL)?
4330 string_sprintf("550 <%s> %s", address, addr->user_message) :
4331 string_sprintf("550 <%s> is not deliverable", address);
4332 log_write(0, LOG_MAIN, "VRFY failed for %s %s",
4333 smtp_cmd_argument, host_and_ident(TRUE));
4338 smtp_printf("%s\r\n", s);
4345 rc = acl_check(ACL_WHERE_EXPN, NULL, acl_smtp_expn, &user_msg, &log_msg);
4347 done = smtp_handle_acl_fail(ACL_WHERE_EXPN, rc, user_msg, log_msg);
4350 BOOL save_log_testing_mode = log_testing_mode;
4351 address_test_mode = log_testing_mode = TRUE;
4352 (void) verify_address(deliver_make_addr(smtp_cmd_data, FALSE),
4353 smtp_out, vopt_is_recipient | vopt_qualify | vopt_expn, -1, -1, -1,
4355 address_test_mode = FALSE;
4356 log_testing_mode = save_log_testing_mode; /* true for -bh */
4365 if (!tls_advertised)
4367 done = synprot_error(L_smtp_protocol_error, 503, NULL,
4368 US"STARTTLS command used when not advertised");
4372 /* Apply an ACL check if one is defined */
4374 if (acl_smtp_starttls != NULL)
4376 rc = acl_check(ACL_WHERE_STARTTLS, NULL, acl_smtp_starttls, &user_msg,
4380 done = smtp_handle_acl_fail(ACL_WHERE_STARTTLS, rc, user_msg, log_msg);
4385 /* RFC 2487 is not clear on when this command may be sent, though it
4386 does state that all information previously obtained from the client
4387 must be discarded if a TLS session is started. It seems reasonble to
4388 do an implied RSET when STARTTLS is received. */
4390 incomplete_transaction_log(US"STARTTLS");
4391 smtp_reset(reset_point);
4393 cmd_list[CMD_LIST_STARTTLS].is_mail_cmd = FALSE;
4395 /* There's an attack where more data is read in past the STARTTLS command
4396 before TLS is negotiated, then assumed to be part of the secure session
4397 when used afterwards; we use segregated input buffers, so are not
4398 vulnerable, but we want to note when it happens and, for sheer paranoia,
4399 ensure that the buffer is "wiped".
4400 Pipelining sync checks will normally have protected us too, unless disabled
4401 by configuration. */
4403 if (receive_smtp_buffered())
4406 debug_printf("Non-empty input buffer after STARTTLS; naive attack?");
4407 if (tls_in.active < 0)
4408 smtp_inend = smtp_inptr = smtp_inbuffer;
4409 /* and if TLS is already active, tls_server_start() should fail */
4412 /* There is nothing we value in the input buffer and if TLS is succesfully
4413 negotiated, we won't use this buffer again; if TLS fails, we'll just read
4414 fresh content into it. The buffer contains arbitrary content from an
4415 untrusted remote source; eg: NOOP <shellcode>\r\nSTARTTLS\r\n
4416 It seems safest to just wipe away the content rather than leave it as a
4417 target to jump to. */
4419 memset(smtp_inbuffer, 0, in_buffer_size);
4421 /* Attempt to start up a TLS session, and if successful, discard all
4422 knowledge that was obtained previously. At least, that's what the RFC says,
4423 and that's what happens by default. However, in order to work round YAEB,
4424 there is an option to remember the esmtp state. Sigh.
4426 We must allow for an extra EHLO command and an extra AUTH command after
4427 STARTTLS that don't add to the nonmail command count. */
4429 if ((rc = tls_server_start(tls_require_ciphers)) == OK)
4431 if (!tls_remember_esmtp)
4432 helo_seen = esmtp = auth_advertised = pipelining_advertised = FALSE;
4433 cmd_list[CMD_LIST_EHLO].is_mail_cmd = TRUE;
4434 cmd_list[CMD_LIST_AUTH].is_mail_cmd = TRUE;
4435 if (sender_helo_name != NULL)
4437 store_free(sender_helo_name);
4438 sender_helo_name = NULL;
4439 host_build_sender_fullhost(); /* Rebuild */
4440 set_process_info("handling incoming TLS connection from %s",
4441 host_and_ident(FALSE));
4443 received_protocol = (esmtp?
4444 protocols[pextend + pcrpted +
4445 ((sender_host_authenticated != NULL)? pauthed : 0)]
4447 protocols[pnormal + pcrpted])
4449 ((sender_host_address != NULL)? pnlocal : 0);
4451 sender_host_authenticated = NULL;
4452 authenticated_id = NULL;
4453 sync_cmd_limit = NON_SYNC_CMD_NON_PIPELINING;
4454 DEBUG(D_tls) debug_printf("TLS active\n");
4455 break; /* Successful STARTTLS */
4458 /* Some local configuration problem was discovered before actually trying
4459 to do a TLS handshake; give a temporary error. */
4461 else if (rc == DEFER)
4463 smtp_printf("454 TLS currently unavailable\r\n");
4467 /* Hard failure. Reject everything except QUIT or closed connection. One
4468 cause for failure is a nested STARTTLS, in which case tls_in.active remains
4469 set, but we must still reject all incoming commands. */
4471 DEBUG(D_tls) debug_printf("TLS failed to start\n");
4474 switch(smtp_read_command(FALSE))
4477 log_write(L_smtp_connection, LOG_MAIN, "%s closed by EOF",
4478 smtp_get_connection_info());
4479 smtp_notquit_exit(US"tls-failed", NULL, NULL);
4483 /* It is perhaps arguable as to which exit ACL should be called here,
4484 but as it is probably a situation that almost never arises, it
4485 probably doesn't matter. We choose to call the real QUIT ACL, which in
4486 some sense is perhaps "right". */
4490 if (acl_smtp_quit != NULL)
4492 rc = acl_check(ACL_WHERE_QUIT, NULL, acl_smtp_quit, &user_msg,
4495 log_write(0, LOG_MAIN|LOG_PANIC, "ACL for QUIT returned ERROR: %s",
4498 if (user_msg == NULL)
4499 smtp_printf("221 %s closing connection\r\n", smtp_active_hostname);
4501 smtp_respond(US"221", 3, TRUE, user_msg);
4502 log_write(L_smtp_connection, LOG_MAIN, "%s closed by QUIT",
4503 smtp_get_connection_info());
4508 smtp_printf("554 Security failure\r\n");
4512 tls_close(TRUE, TRUE);
4517 /* The ACL for QUIT is provided for gathering statistical information or
4518 similar; it does not affect the response code, but it can supply a custom
4523 incomplete_transaction_log(US"QUIT");
4524 if (acl_smtp_quit != NULL)
4526 rc = acl_check(ACL_WHERE_QUIT, NULL, acl_smtp_quit, &user_msg, &log_msg);
4528 log_write(0, LOG_MAIN|LOG_PANIC, "ACL for QUIT returned ERROR: %s",
4531 if (user_msg == NULL)
4532 smtp_printf("221 %s closing connection\r\n", smtp_active_hostname);
4534 smtp_respond(US"221", 3, TRUE, user_msg);
4537 tls_close(TRUE, TRUE);
4541 log_write(L_smtp_connection, LOG_MAIN, "%s closed by QUIT",
4542 smtp_get_connection_info());
4548 incomplete_transaction_log(US"RSET");
4549 smtp_reset(reset_point);
4551 smtp_printf("250 Reset OK\r\n");
4552 cmd_list[CMD_LIST_RSET].is_mail_cmd = FALSE;
4558 smtp_printf("250 OK\r\n");
4562 /* Show ETRN/EXPN/VRFY if there's an ACL for checking hosts; if actually
4563 used, a check will be done for permitted hosts. Show STARTTLS only if not
4564 already in a TLS session and if it would be advertised in the EHLO
4569 smtp_printf("214-Commands supported:\r\n");
4573 Ustrcat(buffer, " AUTH");
4575 if (tls_in.active < 0 &&
4576 verify_check_host(&tls_advertise_hosts) != FAIL)
4577 Ustrcat(buffer, " STARTTLS");
4579 Ustrcat(buffer, " HELO EHLO MAIL RCPT DATA");
4580 Ustrcat(buffer, " NOOP QUIT RSET HELP");
4581 if (acl_smtp_etrn != NULL) Ustrcat(buffer, " ETRN");
4582 if (acl_smtp_expn != NULL) Ustrcat(buffer, " EXPN");
4583 if (acl_smtp_vrfy != NULL) Ustrcat(buffer, " VRFY");
4584 smtp_printf("214%s\r\n", buffer);
4590 incomplete_transaction_log(US"connection lost");
4591 smtp_notquit_exit(US"connection-lost", US"421",
4592 US"%s lost input connection", smtp_active_hostname);
4594 /* Don't log by default unless in the middle of a message, as some mailers
4595 just drop the call rather than sending QUIT, and it clutters up the logs.
4598 if (sender_address != NULL || recipients_count > 0)
4599 log_write(L_lost_incoming_connection,
4601 "unexpected %s while reading SMTP command from %s%s",
4602 sender_host_unknown? "EOF" : "disconnection",
4603 host_and_ident(FALSE), smtp_read_error);
4605 else log_write(L_smtp_connection, LOG_MAIN, "%s lost%s",
4606 smtp_get_connection_info(), smtp_read_error);
4614 if (sender_address != NULL)
4616 done = synprot_error(L_smtp_protocol_error, 503, NULL,
4617 US"ETRN is not permitted inside a transaction");
4621 log_write(L_etrn, LOG_MAIN, "ETRN %s received from %s", smtp_cmd_argument,
4622 host_and_ident(FALSE));
4624 rc = acl_check(ACL_WHERE_ETRN, NULL, acl_smtp_etrn, &user_msg, &log_msg);
4627 done = smtp_handle_acl_fail(ACL_WHERE_ETRN, rc, user_msg, log_msg);
4631 /* Compute the serialization key for this command. */
4633 etrn_serialize_key = string_sprintf("etrn-%s\n", smtp_cmd_data);
4635 /* If a command has been specified for running as a result of ETRN, we
4636 permit any argument to ETRN. If not, only the # standard form is permitted,
4637 since that is strictly the only kind of ETRN that can be implemented
4638 according to the RFC. */
4640 if (smtp_etrn_command != NULL)
4644 etrn_command = smtp_etrn_command;
4645 deliver_domain = smtp_cmd_data;
4646 rc = transport_set_up_command(&argv, smtp_etrn_command, TRUE, 0, NULL,
4647 US"ETRN processing", &error);
4648 deliver_domain = NULL;
4651 log_write(0, LOG_MAIN|LOG_PANIC, "failed to set up ETRN command: %s",
4653 smtp_printf("458 Internal failure\r\n");
4658 /* Else set up to call Exim with the -R option. */
4662 if (*smtp_cmd_data++ != '#')
4664 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4665 US"argument must begin with #");
4668 etrn_command = US"exim -R";
4669 argv = child_exec_exim(CEE_RETURN_ARGV, TRUE, NULL, TRUE, 2, US"-R",
4673 /* If we are host-testing, don't actually do anything. */
4679 debug_printf("ETRN command is: %s\n", etrn_command);
4680 debug_printf("ETRN command execution skipped\n");
4682 if (user_msg == NULL) smtp_printf("250 OK\r\n");
4683 else smtp_user_msg(US"250", user_msg);
4688 /* If ETRN queue runs are to be serialized, check the database to
4689 ensure one isn't already running. */
4691 if (smtp_etrn_serialize && !enq_start(etrn_serialize_key))
4693 smtp_printf("458 Already processing %s\r\n", smtp_cmd_data);
4697 /* Fork a child process and run the command. We don't want to have to
4698 wait for the process at any point, so set SIGCHLD to SIG_IGN before
4699 forking. It should be set that way anyway for external incoming SMTP,
4700 but we save and restore to be tidy. If serialization is required, we
4701 actually run the command in yet another process, so we can wait for it
4702 to complete and then remove the serialization lock. */
4704 oldsignal = signal(SIGCHLD, SIG_IGN);
4706 if ((pid = fork()) == 0)
4708 smtp_input = FALSE; /* This process is not associated with the */
4709 (void)fclose(smtp_in); /* SMTP call any more. */
4710 (void)fclose(smtp_out);
4712 signal(SIGCHLD, SIG_DFL); /* Want to catch child */
4714 /* If not serializing, do the exec right away. Otherwise, fork down
4715 into another process. */
4717 if (!smtp_etrn_serialize || (pid = fork()) == 0)
4719 DEBUG(D_exec) debug_print_argv(argv);
4720 exim_nullstd(); /* Ensure std{in,out,err} exist */
4721 execv(CS argv[0], (char *const *)argv);
4722 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "exec of \"%s\" (ETRN) failed: %s",
4723 etrn_command, strerror(errno));
4724 _exit(EXIT_FAILURE); /* paranoia */
4727 /* Obey this if smtp_serialize and the 2nd fork yielded non-zero. That
4728 is, we are in the first subprocess, after forking again. All we can do
4729 for a failing fork is to log it. Otherwise, wait for the 2nd process to
4730 complete, before removing the serialization. */
4733 log_write(0, LOG_MAIN|LOG_PANIC, "2nd fork for serialized ETRN "
4734 "failed: %s", strerror(errno));
4738 DEBUG(D_any) debug_printf("waiting for serialized ETRN process %d\n",
4740 (void)wait(&status);
4741 DEBUG(D_any) debug_printf("serialized ETRN process %d ended\n",
4745 enq_end(etrn_serialize_key);
4746 _exit(EXIT_SUCCESS);
4749 /* Back in the top level SMTP process. Check that we started a subprocess
4750 and restore the signal state. */
4754 log_write(0, LOG_MAIN|LOG_PANIC, "fork of process for ETRN failed: %s",
4756 smtp_printf("458 Unable to fork process\r\n");
4757 if (smtp_etrn_serialize) enq_end(etrn_serialize_key);
4761 if (user_msg == NULL) smtp_printf("250 OK\r\n");
4762 else smtp_user_msg(US"250", user_msg);
4765 signal(SIGCHLD, oldsignal);
4770 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4771 US"unexpected argument data");
4775 /* This currently happens only for NULLs, but could be extended. */
4778 done = synprot_error(L_smtp_syntax_error, 0, NULL, /* Just logs */
4779 US"NULL character(s) present (shown as '?')");
4780 smtp_printf("501 NULL characters are not allowed in SMTP commands\r\n");
4786 if (smtp_inend >= smtp_inbuffer + in_buffer_size)
4787 smtp_inend = smtp_inbuffer + in_buffer_size - 1;
4788 c = smtp_inend - smtp_inptr;
4789 if (c > 150) c = 150;
4791 incomplete_transaction_log(US"sync failure");
4792 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP protocol synchronization error "
4793 "(next input sent too soon: pipelining was%s advertised): "
4794 "rejected \"%s\" %s next input=\"%s\"",
4795 pipelining_advertised? "" : " not",
4796 smtp_cmd_buffer, host_and_ident(TRUE),
4797 string_printing(smtp_inptr));
4798 smtp_notquit_exit(US"synchronization-error", US"554",
4799 US"SMTP synchronization error");
4800 done = 1; /* Pretend eof - drops connection */
4804 case TOO_MANY_NONMAIL_CMD:
4805 s = smtp_cmd_buffer;
4806 while (*s != 0 && !isspace(*s)) s++;
4807 incomplete_transaction_log(US"too many non-mail commands");
4808 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
4809 "nonmail commands (last was \"%.*s\")", host_and_ident(FALSE),
4810 (int)(s - smtp_cmd_buffer), smtp_cmd_buffer);
4811 smtp_notquit_exit(US"bad-commands", US"554", US"Too many nonmail commands");
4812 done = 1; /* Pretend eof - drops connection */
4815 #ifdef EXPERIMENTAL_PROXY
4816 case PROXY_FAIL_IGNORE_CMD:
4817 smtp_printf("503 Command refused, required Proxy negotiation failed\r\n");
4822 if (unknown_command_count++ >= smtp_max_unknown_commands)
4824 log_write(L_smtp_syntax_error, LOG_MAIN,
4825 "SMTP syntax error in \"%s\" %s %s",
4826 string_printing(smtp_cmd_buffer), host_and_ident(TRUE),
4827 US"unrecognized command");
4828 incomplete_transaction_log(US"unrecognized command");
4829 smtp_notquit_exit(US"bad-commands", US"500",
4830 US"Too many unrecognized commands");
4832 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
4833 "unrecognized commands (last was \"%s\")", host_and_ident(FALSE),
4837 done = synprot_error(L_smtp_syntax_error, 500, NULL,
4838 US"unrecognized command");
4842 /* This label is used by goto's inside loops that want to break out to
4843 the end of the command-processing loop. */
4846 last_was_rej_mail = was_rej_mail; /* Remember some last commands for */
4847 last_was_rcpt = was_rcpt; /* protocol error handling */
4851 return done - 2; /* Convert yield values */
4856 /* End of smtp_in.c */