1 /*************************************************
2 * Exim - an Internet mail transport agent *
3 *************************************************/
5 /* Copyright (c) University of Cambridge 1995 - 2014 */
6 /* See the file NOTICE for conditions of use and distribution. */
8 /* Functions for handling an incoming SMTP call. */
14 /* Initialize for TCP wrappers if so configured. It appears that the macro
15 HAVE_IPV6 is used in some versions of the tcpd.h header, so we unset it before
16 including that header, and restore its value afterwards. */
18 #ifdef USE_TCP_WRAPPERS
21 #define EXIM_HAVE_IPV6
27 #define HAVE_IPV6 TRUE
30 int allow_severity = LOG_INFO;
31 int deny_severity = LOG_NOTICE;
32 uschar *tcp_wrappers_name;
36 /* Size of buffer for reading SMTP commands. We used to use 512, as defined
37 by RFC 821. However, RFC 1869 specifies that this must be increased for SMTP
38 commands that accept arguments, and this in particular applies to AUTH, where
39 the data can be quite long. More recently this value was 2048 in Exim;
40 however, RFC 4954 (circa 2007) recommends 12288 bytes to handle AUTH. Clients
41 such as Thunderbird will send an AUTH with an initial-response for GSSAPI.
42 The maximum size of a Kerberos ticket under Windows 2003 is 12000 bytes, and
43 we need room to handle large base64-encoded AUTHs for GSSAPI.
46 #define smtp_cmd_buffer_size 16384
48 /* Size of buffer for reading SMTP incoming packets */
50 #define in_buffer_size 8192
52 /* Structure for SMTP command list */
59 short int is_mail_cmd;
62 /* Codes for identifying commands. We order them so that those that come first
63 are those for which synchronization is always required. Checking this can help
67 /* These commands are required to be synchronized, i.e. to be the last in a
68 block of commands when pipelining. */
70 HELO_CMD, EHLO_CMD, DATA_CMD, /* These are listed in the pipelining */
71 VRFY_CMD, EXPN_CMD, NOOP_CMD, /* RFC as requiring synchronization */
72 ETRN_CMD, /* This by analogy with TURN from the RFC */
73 STARTTLS_CMD, /* Required by the STARTTLS RFC */
75 /* This is a dummy to identify the non-sync commands when pipelining */
77 NON_SYNC_CMD_PIPELINING,
79 /* These commands need not be synchronized when pipelining */
81 MAIL_CMD, RCPT_CMD, RSET_CMD,
83 /* This is a dummy to identify the non-sync commands when not pipelining */
85 NON_SYNC_CMD_NON_PIPELINING,
87 /* I have been unable to find a statement about the use of pipelining
88 with AUTH, so to be on the safe side it is here, though I kind of feel
89 it should be up there with the synchronized commands. */
93 /* I'm not sure about these, but I don't think they matter. */
97 #ifdef EXPERIMENTAL_PROXY
98 PROXY_FAIL_IGNORE_CMD,
101 /* These are specials that don't correspond to actual commands */
103 EOF_CMD, OTHER_CMD, BADARG_CMD, BADCHAR_CMD, BADSYN_CMD,
104 TOO_MANY_NONMAIL_CMD };
107 /* This is a convenience macro for adding the identity of an SMTP command
108 to the circular buffer that holds a list of the last n received. */
111 smtp_connection_had[smtp_ch_index++] = n; \
112 if (smtp_ch_index >= SMTP_HBUFF_SIZE) smtp_ch_index = 0
115 /*************************************************
116 * Local static variables *
117 *************************************************/
119 static auth_instance *authenticated_by;
120 static BOOL auth_advertised;
122 static BOOL tls_advertised;
124 static BOOL dsn_advertised;
126 static BOOL helo_required = FALSE;
127 static BOOL helo_verify = FALSE;
128 static BOOL helo_seen;
129 static BOOL helo_accept_junk;
130 static BOOL count_nonmail;
131 static BOOL pipelining_advertised;
132 static BOOL rcpt_smtp_response_same;
133 static BOOL rcpt_in_progress;
134 static int nonmail_command_count;
135 static BOOL smtp_exit_function_called = 0;
136 #ifdef EXPERIMENTAL_INTERNATIONAL
137 static BOOL smtputf8_advertised;
139 static int synprot_error_count;
140 static int unknown_command_count;
141 static int sync_cmd_limit;
142 static int smtp_write_error = 0;
144 static uschar *rcpt_smtp_response;
145 static uschar *smtp_data_buffer;
146 static uschar *smtp_cmd_data;
148 /* We need to know the position of RSET, HELO, EHLO, AUTH, and STARTTLS. Their
149 final fields of all except AUTH are forced TRUE at the start of a new message
150 setup, to allow one of each between messages that is not counted as a nonmail
151 command. (In fact, only one of HELO/EHLO is not counted.) Also, we have to
152 allow a new EHLO after starting up TLS.
154 AUTH is "falsely" labelled as a mail command initially, so that it doesn't get
155 counted. However, the flag is changed when AUTH is received, so that multiple
156 failing AUTHs will eventually hit the limit. After a successful AUTH, another
157 AUTH is already forbidden. After a TLS session is started, AUTH's flag is again
158 forced TRUE, to allow for the re-authentication that can happen at that point.
160 QUIT is also "falsely" labelled as a mail command so that it doesn't up the
161 count of non-mail commands and possibly provoke an error. */
163 static smtp_cmd_list cmd_list[] = {
164 /* name len cmd has_arg is_mail_cmd */
166 { "rset", sizeof("rset")-1, RSET_CMD, FALSE, FALSE }, /* First */
167 { "helo", sizeof("helo")-1, HELO_CMD, TRUE, FALSE },
168 { "ehlo", sizeof("ehlo")-1, EHLO_CMD, TRUE, FALSE },
169 { "auth", sizeof("auth")-1, AUTH_CMD, TRUE, TRUE },
171 { "starttls", sizeof("starttls")-1, STARTTLS_CMD, FALSE, FALSE },
174 /* If you change anything above here, also fix the definitions below. */
176 { "mail from:", sizeof("mail from:")-1, MAIL_CMD, TRUE, TRUE },
177 { "rcpt to:", sizeof("rcpt to:")-1, RCPT_CMD, TRUE, TRUE },
178 { "data", sizeof("data")-1, DATA_CMD, FALSE, TRUE },
179 { "quit", sizeof("quit")-1, QUIT_CMD, FALSE, TRUE },
180 { "noop", sizeof("noop")-1, NOOP_CMD, TRUE, FALSE },
181 { "etrn", sizeof("etrn")-1, ETRN_CMD, TRUE, FALSE },
182 { "vrfy", sizeof("vrfy")-1, VRFY_CMD, TRUE, FALSE },
183 { "expn", sizeof("expn")-1, EXPN_CMD, TRUE, FALSE },
184 { "help", sizeof("help")-1, HELP_CMD, TRUE, FALSE }
187 static smtp_cmd_list *cmd_list_end =
188 cmd_list + sizeof(cmd_list)/sizeof(smtp_cmd_list);
190 #define CMD_LIST_RSET 0
191 #define CMD_LIST_HELO 1
192 #define CMD_LIST_EHLO 2
193 #define CMD_LIST_AUTH 3
194 #define CMD_LIST_STARTTLS 4
196 /* This list of names is used for performing the smtp_no_mail logging action.
197 It must be kept in step with the SCH_xxx enumerations. */
199 static uschar *smtp_names[] =
201 US"NONE", US"AUTH", US"DATA", US"EHLO", US"ETRN", US"EXPN", US"HELO",
202 US"HELP", US"MAIL", US"NOOP", US"QUIT", US"RCPT", US"RSET", US"STARTTLS",
205 static uschar *protocols[] = {
206 US"local-smtp", /* HELO */
207 US"local-smtps", /* The rare case EHLO->STARTTLS->HELO */
208 US"local-esmtp", /* EHLO */
209 US"local-esmtps", /* EHLO->STARTTLS->EHLO */
210 US"local-esmtpa", /* EHLO->AUTH */
211 US"local-esmtpsa" /* EHLO->STARTTLS->EHLO->AUTH */
216 #define pcrpted 1 /* added to pextend or pnormal */
217 #define pauthed 2 /* added to pextend */
218 #define pnlocal 6 /* offset to remove "local" */
220 /* Sanity check and validate optional args to MAIL FROM: envelope */
222 ENV_MAIL_OPT_SIZE, ENV_MAIL_OPT_BODY, ENV_MAIL_OPT_AUTH,
226 ENV_MAIL_OPT_RET, ENV_MAIL_OPT_ENVID,
227 #ifdef EXPERIMENTAL_INTERNATIONAL
233 uschar * name; /* option requested during MAIL cmd */
234 int value; /* enum type */
235 BOOL need_value; /* TRUE requires value (name=value pair format)
236 FALSE is a singleton */
238 static env_mail_type_t env_mail_type_list[] = {
239 { US"SIZE", ENV_MAIL_OPT_SIZE, TRUE },
240 { US"BODY", ENV_MAIL_OPT_BODY, TRUE },
241 { US"AUTH", ENV_MAIL_OPT_AUTH, TRUE },
243 { US"PRDR", ENV_MAIL_OPT_PRDR, FALSE },
245 { US"RET", ENV_MAIL_OPT_RET, TRUE },
246 { US"ENVID", ENV_MAIL_OPT_ENVID, TRUE },
247 #ifdef EXPERIMENTAL_INTERNATIONAL
248 { US"SMTPUTF8",ENV_MAIL_OPT_UTF8, FALSE }, /* rfc6531 */
250 { US"NULL", ENV_MAIL_OPT_NULL, FALSE }
253 /* When reading SMTP from a remote host, we have to use our own versions of the
254 C input-reading functions, in order to be able to flush the SMTP output only
255 when about to read more data from the socket. This is the only way to get
256 optimal performance when the client is using pipelining. Flushing for every
257 command causes a separate packet and reply packet each time; saving all the
258 responses up (when pipelining) combines them into one packet and one response.
260 For simplicity, these functions are used for *all* SMTP input, not only when
261 receiving over a socket. However, after setting up a secure socket (SSL), input
262 is read via the OpenSSL library, and another set of functions is used instead
265 These functions are set in the receive_getc etc. variables and called with the
266 same interface as the C functions. However, since there can only ever be
267 one incoming SMTP call, we just use a single buffer and flags. There is no need
268 to implement a complicated private FILE-like structure.*/
270 static uschar *smtp_inbuffer;
271 static uschar *smtp_inptr;
272 static uschar *smtp_inend;
273 static int smtp_had_eof;
274 static int smtp_had_error;
277 /*************************************************
278 * SMTP version of getc() *
279 *************************************************/
281 /* This gets the next byte from the SMTP input buffer. If the buffer is empty,
282 it flushes the output, and refills the buffer, with a timeout. The signal
283 handler is set appropriately by the calling function. This function is not used
284 after a connection has negotated itself into an TLS/SSL state.
287 Returns: the next character or EOF
293 if (smtp_inptr >= smtp_inend)
297 if (smtp_receive_timeout > 0) alarm(smtp_receive_timeout);
298 rc = read(fileno(smtp_in), smtp_inbuffer, in_buffer_size);
303 /* Must put the error text in fixed store, because this might be during
304 header reading, where it releases unused store above the header. */
307 smtp_had_error = save_errno;
308 smtp_read_error = string_copy_malloc(
309 string_sprintf(" (error: %s)", strerror(save_errno)));
311 else smtp_had_eof = 1;
315 dkim_exim_verify_feed(smtp_inbuffer, rc);
317 smtp_inend = smtp_inbuffer + rc;
318 smtp_inptr = smtp_inbuffer;
320 return *smtp_inptr++;
325 /*************************************************
326 * SMTP version of ungetc() *
327 *************************************************/
329 /* Puts a character back in the input buffer. Only ever
335 Returns: the character
341 *(--smtp_inptr) = ch;
348 /*************************************************
349 * SMTP version of feof() *
350 *************************************************/
352 /* Tests for a previous EOF
355 Returns: non-zero if the eof flag is set
367 /*************************************************
368 * SMTP version of ferror() *
369 *************************************************/
371 /* Tests for a previous read error, and returns with errno
372 restored to what it was when the error was detected.
375 Returns: non-zero if the error flag is set
381 errno = smtp_had_error;
382 return smtp_had_error;
387 /*************************************************
388 * Test for characters in the SMTP buffer *
389 *************************************************/
391 /* Used at the end of a message
400 return smtp_inptr < smtp_inend;
405 /*************************************************
406 * Write formatted string to SMTP channel *
407 *************************************************/
409 /* This is a separate function so that we don't have to repeat everything for
410 TLS support or debugging. It is global so that the daemon and the
411 authentication functions can use it. It does not return any error indication,
412 because major problems such as dropped connections won't show up till an output
413 flush for non-TLS connections. The smtp_fflush() function is available for
414 checking that: for convenience, TLS output errors are remembered here so that
415 they are also picked up later by smtp_fflush().
419 ... optional arguments
425 smtp_printf(const char *format, ...)
429 va_start(ap, format);
430 smtp_vprintf(format, ap);
434 /* This is split off so that verify.c:respond_printf() can, in effect, call
435 smtp_printf(), bearing in mind that in C a vararg function can't directly
436 call another vararg function, only a function which accepts a va_list. */
439 smtp_vprintf(const char *format, va_list ap)
443 yield = string_vformat(big_buffer, big_buffer_size, format, ap);
447 void *reset_point = store_get(0);
448 uschar *msg_copy, *cr, *end;
449 msg_copy = string_copy(big_buffer);
450 end = msg_copy + Ustrlen(msg_copy);
451 while ((cr = Ustrchr(msg_copy, '\r')) != NULL) /* lose CRs */
452 memmove(cr, cr + 1, (end--) - cr);
453 debug_printf("SMTP>> %s", msg_copy);
454 store_reset(reset_point);
459 log_write(0, LOG_MAIN|LOG_PANIC, "string too large in smtp_printf()");
460 smtp_closedown(US"Unexpected error");
461 exim_exit(EXIT_FAILURE);
464 /* If this is the first output for a (non-batch) RCPT command, see if all RCPTs
465 have had the same. Note: this code is also present in smtp_respond(). It would
466 be tidier to have it only in one place, but when it was added, it was easier to
467 do it that way, so as not to have to mess with the code for the RCPT command,
468 which sometimes uses smtp_printf() and sometimes smtp_respond(). */
470 if (rcpt_in_progress)
472 if (rcpt_smtp_response == NULL)
473 rcpt_smtp_response = string_copy(big_buffer);
474 else if (rcpt_smtp_response_same &&
475 Ustrcmp(rcpt_smtp_response, big_buffer) != 0)
476 rcpt_smtp_response_same = FALSE;
477 rcpt_in_progress = FALSE;
480 /* Now write the string */
483 if (tls_in.active >= 0)
485 if (tls_write(TRUE, big_buffer, Ustrlen(big_buffer)) < 0)
486 smtp_write_error = -1;
491 if (fprintf(smtp_out, "%s", big_buffer) < 0) smtp_write_error = -1;
496 /*************************************************
497 * Flush SMTP out and check for error *
498 *************************************************/
500 /* This function isn't currently used within Exim (it detects errors when it
501 tries to read the next SMTP input), but is available for use in local_scan().
502 For non-TLS connections, it flushes the output and checks for errors. For
503 TLS-connections, it checks for a previously-detected TLS write error.
506 Returns: 0 for no error; -1 after an error
512 if (tls_in.active < 0 && fflush(smtp_out) != 0) smtp_write_error = -1;
513 return smtp_write_error;
518 /*************************************************
519 * SMTP command read timeout *
520 *************************************************/
522 /* Signal handler for timing out incoming SMTP commands. This attempts to
525 Argument: signal number (SIGALRM)
530 command_timeout_handler(int sig)
532 sig = sig; /* Keep picky compilers happy */
533 log_write(L_lost_incoming_connection,
534 LOG_MAIN, "SMTP command timeout on%s connection from %s",
535 (tls_in.active >= 0)? " TLS" : "",
536 host_and_ident(FALSE));
537 if (smtp_batched_input)
538 moan_smtp_batch(NULL, "421 SMTP command timeout"); /* Does not return */
539 smtp_notquit_exit(US"command-timeout", US"421",
540 US"%s: SMTP command timeout - closing connection", smtp_active_hostname);
541 exim_exit(EXIT_FAILURE);
546 /*************************************************
548 *************************************************/
550 /* Signal handler for handling SIGTERM. Again, try to finish tidily.
552 Argument: signal number (SIGTERM)
557 command_sigterm_handler(int sig)
559 sig = sig; /* Keep picky compilers happy */
560 log_write(0, LOG_MAIN, "%s closed after SIGTERM", smtp_get_connection_info());
561 if (smtp_batched_input)
562 moan_smtp_batch(NULL, "421 SIGTERM received"); /* Does not return */
563 smtp_notquit_exit(US"signal-exit", US"421",
564 US"%s: Service not available - closing connection", smtp_active_hostname);
565 exim_exit(EXIT_FAILURE);
571 #ifdef EXPERIMENTAL_PROXY
572 /*************************************************
573 * Restore socket timeout to previous value *
574 *************************************************/
575 /* If the previous value was successfully retrieved, restore
576 it before returning control to the non-proxy routines
578 Arguments: fd - File descriptor for input
579 get_ok - Successfully retrieved previous values
580 tvtmp - Time struct with previous values
581 vslen - Length of time struct
585 restore_socket_timeout(int fd, int get_ok, struct timeval tvtmp, socklen_t vslen)
588 setsockopt(fd, SOL_SOCKET, SO_RCVTIMEO, (char *)&tvtmp, vslen);
591 /*************************************************
592 * Check if host is required proxy host *
593 *************************************************/
594 /* The function determines if inbound host will be a regular smtp host
595 or if it is configured that it must use Proxy Protocol.
602 check_proxy_protocol_host()
605 /* Cannot configure local connection as a proxy inbound */
606 if (sender_host_address == NULL) return proxy_session;
608 rc = verify_check_this_host(&proxy_required_hosts, NULL, NULL,
609 sender_host_address, NULL);
613 debug_printf("Detected proxy protocol configured host\n");
614 proxy_session = TRUE;
616 return proxy_session;
620 /*************************************************
621 * Setup host for proxy protocol *
622 *************************************************/
623 /* The function configures the connection based on a header from the
624 inbound host to use Proxy Protocol. The specification is very exact
625 so exit with an error if do not find the exact required pieces. This
626 includes an incorrect number of spaces separating args.
633 setup_proxy_protocol_host()
645 struct { /* TCP/UDP over IPv4, len = 12 */
651 struct { /* TCP/UDP over IPv6, len = 36 */
652 uint8_t src_addr[16];
653 uint8_t dst_addr[16];
657 struct { /* AF_UNIX sockets, len = 216 */
658 uschar src_addr[108];
659 uschar dst_addr[108];
665 /* Temp variables used in PPv2 address:port parsing */
667 char tmpip[INET_ADDRSTRLEN];
668 struct sockaddr_in tmpaddr;
669 char tmpip6[INET6_ADDRSTRLEN];
670 struct sockaddr_in6 tmpaddr6;
674 const char v2sig[12] = "\x0D\x0A\x0D\x0A\x00\x0D\x0A\x51\x55\x49\x54\x0A";
675 uschar *iptype; /* To display debug info */
678 struct timeval tvtmp;
680 vslen = sizeof(struct timeval);
682 fd = fileno(smtp_in);
684 /* Save current socket timeout values */
685 get_ok = getsockopt(fd, SOL_SOCKET, SO_RCVTIMEO, (char *)&tvtmp,
688 /* Proxy Protocol host must send header within a short time
689 (default 3 seconds) or it's considered invalid */
690 tv.tv_sec = PROXY_NEGOTIATION_TIMEOUT_SEC;
691 tv.tv_usec = PROXY_NEGOTIATION_TIMEOUT_USEC;
692 setsockopt(fd, SOL_SOCKET, SO_RCVTIMEO, (char *)&tv,
693 sizeof(struct timeval));
697 /* The inbound host was declared to be a Proxy Protocol host, so
698 don't do a PEEK into the data, actually slurp it up. */
699 ret = recv(fd, &hdr, sizeof(hdr), 0);
701 while (ret == -1 && errno == EINTR);
705 restore_socket_timeout(fd, get_ok, tvtmp, vslen);
706 return (errno == EAGAIN) ? 0 : ERRNO_PROXYFAIL;
710 memcmp(&hdr.v2, v2sig, 12) == 0)
714 /* May 2014: haproxy combined the version and command into one byte to
715 allow two full bytes for the length field in order to proxy SSL
716 connections. SSL Proxy is not supported in this version of Exim, but
717 must still seperate values here. */
718 ver = (hdr.v2.ver_cmd & 0xf0) >> 4;
719 cmd = (hdr.v2.ver_cmd & 0x0f);
723 DEBUG(D_receive) debug_printf("Invalid Proxy Protocol version: %d\n", ver);
726 DEBUG(D_receive) debug_printf("Detected PROXYv2 header\n");
727 /* The v2 header will always be 16 bytes per the spec. */
728 size = 16 + hdr.v2.len;
731 DEBUG(D_receive) debug_printf("Truncated or too large PROXYv2 header (%d/%d)\n",
737 case 0x01: /* PROXY command */
740 case 0x11: /* TCPv4 address type */
742 tmpaddr.sin_addr.s_addr = hdr.v2.addr.ip4.src_addr;
743 inet_ntop(AF_INET, &(tmpaddr.sin_addr), (char *)&tmpip, sizeof(tmpip));
744 if (!string_is_ip_address(US tmpip,NULL))
746 DEBUG(D_receive) debug_printf("Invalid %s source IP\n", iptype);
747 return ERRNO_PROXYFAIL;
749 proxy_host_address = sender_host_address;
750 sender_host_address = string_copy(US tmpip);
751 tmpport = ntohs(hdr.v2.addr.ip4.src_port);
752 proxy_host_port = sender_host_port;
753 sender_host_port = tmpport;
754 /* Save dest ip/port */
755 tmpaddr.sin_addr.s_addr = hdr.v2.addr.ip4.dst_addr;
756 inet_ntop(AF_INET, &(tmpaddr.sin_addr), (char *)&tmpip, sizeof(tmpip));
757 if (!string_is_ip_address(US tmpip,NULL))
759 DEBUG(D_receive) debug_printf("Invalid %s dest port\n", iptype);
760 return ERRNO_PROXYFAIL;
762 proxy_target_address = string_copy(US tmpip);
763 tmpport = ntohs(hdr.v2.addr.ip4.dst_port);
764 proxy_target_port = tmpport;
766 case 0x21: /* TCPv6 address type */
768 memmove(tmpaddr6.sin6_addr.s6_addr, hdr.v2.addr.ip6.src_addr, 16);
769 inet_ntop(AF_INET6, &(tmpaddr6.sin6_addr), (char *)&tmpip6, sizeof(tmpip6));
770 if (!string_is_ip_address(US tmpip6,NULL))
772 DEBUG(D_receive) debug_printf("Invalid %s source IP\n", iptype);
773 return ERRNO_PROXYFAIL;
775 proxy_host_address = sender_host_address;
776 sender_host_address = string_copy(US tmpip6);
777 tmpport = ntohs(hdr.v2.addr.ip6.src_port);
778 proxy_host_port = sender_host_port;
779 sender_host_port = tmpport;
780 /* Save dest ip/port */
781 memmove(tmpaddr6.sin6_addr.s6_addr, hdr.v2.addr.ip6.dst_addr, 16);
782 inet_ntop(AF_INET6, &(tmpaddr6.sin6_addr), (char *)&tmpip6, sizeof(tmpip6));
783 if (!string_is_ip_address(US tmpip6,NULL))
785 DEBUG(D_receive) debug_printf("Invalid %s dest port\n", iptype);
786 return ERRNO_PROXYFAIL;
788 proxy_target_address = string_copy(US tmpip6);
789 tmpport = ntohs(hdr.v2.addr.ip6.dst_port);
790 proxy_target_port = tmpport;
794 debug_printf("Unsupported PROXYv2 connection type: 0x%02x\n",
798 /* Unsupported protocol, keep local connection address */
800 case 0x00: /* LOCAL command */
801 /* Keep local connection address for LOCAL */
805 debug_printf("Unsupported PROXYv2 command: 0x%x\n", cmd);
810 memcmp(hdr.v1.line, "PROXY", 5) == 0)
812 uschar *p = string_copy(hdr.v1.line);
813 uschar *end = memchr(p, '\r', ret - 1);
814 uschar *sp; /* Utility variables follow */
818 if (!end || end[1] != '\n')
820 DEBUG(D_receive) debug_printf("Partial or invalid PROXY header\n");
823 *end = '\0'; /* Terminate the string */
824 size = end + 2 - hdr.v1.line; /* Skip header + CRLF */
825 DEBUG(D_receive) debug_printf("Detected PROXYv1 header\n");
826 /* Step through the string looking for the required fields. Ensure
827 strict adherance to required formatting, exit for any error. */
829 if (!isspace(*(p++)))
831 DEBUG(D_receive) debug_printf("Missing space after PROXY command\n");
834 if (!Ustrncmp(p, CCS"TCP4", 4))
836 else if (!Ustrncmp(p,CCS"TCP6", 4))
838 else if (!Ustrncmp(p,CCS"UNKNOWN", 7))
840 iptype = US"Unknown";
845 DEBUG(D_receive) debug_printf("Invalid TCP type\n");
849 p += Ustrlen(iptype);
850 if (!isspace(*(p++)))
852 DEBUG(D_receive) debug_printf("Missing space after TCP4/6 command\n");
855 /* Find the end of the arg */
856 if ((sp = Ustrchr(p, ' ')) == NULL)
859 debug_printf("Did not find proxied src %s\n", iptype);
863 if(!string_is_ip_address(p,NULL))
866 debug_printf("Proxied src arg is not an %s address\n", iptype);
869 proxy_host_address = sender_host_address;
870 sender_host_address = p;
872 if ((sp = Ustrchr(p, ' ')) == NULL)
875 debug_printf("Did not find proxy dest %s\n", iptype);
879 if(!string_is_ip_address(p,NULL))
882 debug_printf("Proxy dest arg is not an %s address\n", iptype);
885 proxy_target_address = p;
887 if ((sp = Ustrchr(p, ' ')) == NULL)
889 DEBUG(D_receive) debug_printf("Did not find proxied src port\n");
893 tmp_port = strtol(CCS p,&endc,10);
894 if (*endc || tmp_port == 0)
897 debug_printf("Proxied src port '%s' not an integer\n", p);
900 proxy_host_port = sender_host_port;
901 sender_host_port = tmp_port;
903 if ((sp = Ustrchr(p, '\0')) == NULL)
905 DEBUG(D_receive) debug_printf("Did not find proxy dest port\n");
908 tmp_port = strtol(CCS p,&endc,10);
909 if (*endc || tmp_port == 0)
912 debug_printf("Proxy dest port '%s' not an integer\n", p);
915 proxy_target_port = tmp_port;
916 /* Already checked for /r /n above. Good V1 header received. */
922 DEBUG(D_receive) debug_printf("Invalid proxy protocol version negotiation\n");
927 restore_socket_timeout(fd, get_ok, tvtmp, vslen);
928 /* Don't flush any potential buffer contents. Any input should cause a
929 synchronization failure */
933 restore_socket_timeout(fd, get_ok, tvtmp, vslen);
935 debug_printf("Valid %s sender from Proxy Protocol header\n", iptype);
936 return proxy_session;
940 /*************************************************
941 * Read one command line *
942 *************************************************/
944 /* Strictly, SMTP commands coming over the net are supposed to end with CRLF.
945 There are sites that don't do this, and in any case internal SMTP probably
946 should check only for LF. Consequently, we check here for LF only. The line
947 ends up with [CR]LF removed from its end. If we get an overlong line, treat as
948 an unknown command. The command is read into the global smtp_cmd_buffer so that
949 it is available via $smtp_command.
951 The character reading routine sets up a timeout for each block actually read
952 from the input (which may contain more than one command). We set up a special
953 signal handler that closes down the session on a timeout. Control does not
957 check_sync if TRUE, check synchronization rules if global option is TRUE
959 Returns: a code identifying the command (enumerated above)
963 smtp_read_command(BOOL check_sync)
968 BOOL hadnull = FALSE;
970 os_non_restarting_signal(SIGALRM, command_timeout_handler);
972 while ((c = (receive_getc)()) != '\n' && c != EOF)
974 if (ptr >= smtp_cmd_buffer_size)
976 os_non_restarting_signal(SIGALRM, sigalrm_handler);
984 smtp_cmd_buffer[ptr++] = c;
987 receive_linecount++; /* For BSMTP errors */
988 os_non_restarting_signal(SIGALRM, sigalrm_handler);
990 /* If hit end of file, return pseudo EOF command. Whether we have a
991 part-line already read doesn't matter, since this is an error state. */
993 if (c == EOF) return EOF_CMD;
995 /* Remove any CR and white space at the end of the line, and terminate the
998 while (ptr > 0 && isspace(smtp_cmd_buffer[ptr-1])) ptr--;
999 smtp_cmd_buffer[ptr] = 0;
1001 DEBUG(D_receive) debug_printf("SMTP<< %s\n", smtp_cmd_buffer);
1003 /* NULLs are not allowed in SMTP commands */
1005 if (hadnull) return BADCHAR_CMD;
1007 /* Scan command list and return identity, having set the data pointer
1008 to the start of the actual data characters. Check for SMTP synchronization
1011 for (p = cmd_list; p < cmd_list_end; p++)
1013 #ifdef EXPERIMENTAL_PROXY
1014 /* Only allow QUIT command if Proxy Protocol parsing failed */
1015 if (proxy_session && proxy_session_failed)
1017 if (p->cmd != QUIT_CMD)
1021 if (strncmpic(smtp_cmd_buffer, US p->name, p->len) == 0 &&
1022 (smtp_cmd_buffer[p->len-1] == ':' || /* "mail from:" or "rcpt to:" */
1023 smtp_cmd_buffer[p->len] == 0 ||
1024 smtp_cmd_buffer[p->len] == ' '))
1026 if (smtp_inptr < smtp_inend && /* Outstanding input */
1027 p->cmd < sync_cmd_limit && /* Command should sync */
1028 check_sync && /* Local flag set */
1029 smtp_enforce_sync && /* Global flag set */
1030 sender_host_address != NULL && /* Not local input */
1031 !sender_host_notsocket) /* Really is a socket */
1034 /* The variables $smtp_command and $smtp_command_argument point into the
1035 unmodified input buffer. A copy of the latter is taken for actual
1036 processing, so that it can be chopped up into separate parts if necessary,
1037 for example, when processing a MAIL command options such as SIZE that can
1038 follow the sender address. */
1040 smtp_cmd_argument = smtp_cmd_buffer + p->len;
1041 while (isspace(*smtp_cmd_argument)) smtp_cmd_argument++;
1042 Ustrcpy(smtp_data_buffer, smtp_cmd_argument);
1043 smtp_cmd_data = smtp_data_buffer;
1045 /* Count non-mail commands from those hosts that are controlled in this
1046 way. The default is all hosts. We don't waste effort checking the list
1047 until we get a non-mail command, but then cache the result to save checking
1048 again. If there's a DEFER while checking the host, assume it's in the list.
1050 Note that one instance of RSET, EHLO/HELO, and STARTTLS is allowed at the
1051 start of each incoming message by fiddling with the value in the table. */
1053 if (!p->is_mail_cmd)
1055 if (count_nonmail == TRUE_UNSET) count_nonmail =
1056 verify_check_host(&smtp_accept_max_nonmail_hosts) != FAIL;
1057 if (count_nonmail && ++nonmail_command_count > smtp_accept_max_nonmail)
1058 return TOO_MANY_NONMAIL_CMD;
1061 /* If there is data for a command that does not expect it, generate the
1064 return (p->has_arg || *smtp_cmd_data == 0)? p->cmd : BADARG_CMD;
1068 #ifdef EXPERIMENTAL_PROXY
1069 /* Only allow QUIT command if Proxy Protocol parsing failed */
1070 if (proxy_session && proxy_session_failed)
1071 return PROXY_FAIL_IGNORE_CMD;
1074 /* Enforce synchronization for unknown commands */
1076 if (smtp_inptr < smtp_inend && /* Outstanding input */
1077 check_sync && /* Local flag set */
1078 smtp_enforce_sync && /* Global flag set */
1079 sender_host_address != NULL && /* Not local input */
1080 !sender_host_notsocket) /* Really is a socket */
1088 /*************************************************
1089 * Recheck synchronization *
1090 *************************************************/
1092 /* Synchronization checks can never be perfect because a packet may be on its
1093 way but not arrived when the check is done. Such checks can in any case only be
1094 done when TLS is not in use. Normally, the checks happen when commands are
1095 read: Exim ensures that there is no more input in the input buffer. In normal
1096 cases, the response to the command will be fast, and there is no further check.
1098 However, for some commands an ACL is run, and that can include delays. In those
1099 cases, it is useful to do another check on the input just before sending the
1100 response. This also applies at the start of a connection. This function does
1101 that check by means of the select() function, as long as the facility is not
1102 disabled or inappropriate. A failure of select() is ignored.
1104 When there is unwanted input, we read it so that it appears in the log of the
1108 Returns: TRUE if all is well; FALSE if there is input pending
1116 struct timeval tzero;
1118 if (!smtp_enforce_sync || sender_host_address == NULL ||
1119 sender_host_notsocket || tls_in.active >= 0)
1122 fd = fileno(smtp_in);
1127 rc = select(fd + 1, (SELECT_ARG2_TYPE *)&fds, NULL, NULL, &tzero);
1129 if (rc <= 0) return TRUE; /* Not ready to read */
1131 if (rc < 0) return TRUE; /* End of file or error */
1134 rc = smtp_inend - smtp_inptr;
1135 if (rc > 150) rc = 150;
1142 /*************************************************
1143 * Forced closedown of call *
1144 *************************************************/
1146 /* This function is called from log.c when Exim is dying because of a serious
1147 disaster, and also from some other places. If an incoming non-batched SMTP
1148 channel is open, it swallows the rest of the incoming message if in the DATA
1149 phase, sends the reply string, and gives an error to all subsequent commands
1150 except QUIT. The existence of an SMTP call is detected by the non-NULLness of
1154 message SMTP reply string to send, excluding the code
1160 smtp_closedown(uschar *message)
1162 if (smtp_in == NULL || smtp_batched_input) return;
1163 receive_swallow_smtp();
1164 smtp_printf("421 %s\r\n", message);
1168 switch(smtp_read_command(FALSE))
1174 smtp_printf("221 %s closing connection\r\n", smtp_active_hostname);
1179 smtp_printf("250 Reset OK\r\n");
1183 smtp_printf("421 %s\r\n", message);
1192 /*************************************************
1193 * Set up connection info for logging *
1194 *************************************************/
1196 /* This function is called when logging information about an SMTP connection.
1197 It sets up appropriate source information, depending on the type of connection.
1198 If sender_fullhost is NULL, we are at a very early stage of the connection;
1199 just use the IP address.
1202 Returns: a string describing the connection
1206 smtp_get_connection_info(void)
1208 uschar *hostname = (sender_fullhost == NULL)?
1209 sender_host_address : sender_fullhost;
1212 return string_sprintf("SMTP connection from %s", hostname);
1214 if (sender_host_unknown || sender_host_notsocket)
1215 return string_sprintf("SMTP connection from %s", sender_ident);
1218 return string_sprintf("SMTP connection from %s (via inetd)", hostname);
1220 if ((log_extra_selector & LX_incoming_interface) != 0 &&
1221 interface_address != NULL)
1222 return string_sprintf("SMTP connection from %s I=[%s]:%d", hostname,
1223 interface_address, interface_port);
1225 return string_sprintf("SMTP connection from %s", hostname);
1231 /* Append TLS-related information to a log line
1234 s String under construction: allocated string to extend, or NULL
1235 sizep Pointer to current allocation size (update on return), or NULL
1236 ptrp Pointer to index for new entries in string (update on return), or NULL
1238 Returns: Allocated string or NULL
1241 s_tlslog(uschar * s, int * sizep, int * ptrp)
1243 int size = sizep ? *sizep : 0;
1244 int ptr = ptrp ? *ptrp : 0;
1246 if ((log_extra_selector & LX_tls_cipher) != 0 && tls_in.cipher != NULL)
1247 s = string_append(s, &size, &ptr, 2, US" X=", tls_in.cipher);
1248 if ((log_extra_selector & LX_tls_certificate_verified) != 0 &&
1249 tls_in.cipher != NULL)
1250 s = string_append(s, &size, &ptr, 2, US" CV=",
1251 tls_in.certificate_verified? "yes":"no");
1252 if ((log_extra_selector & LX_tls_peerdn) != 0 && tls_in.peerdn != NULL)
1253 s = string_append(s, &size, &ptr, 3, US" DN=\"",
1254 string_printing(tls_in.peerdn), US"\"");
1255 if ((log_extra_selector & LX_tls_sni) != 0 && tls_in.sni != NULL)
1256 s = string_append(s, &size, &ptr, 3, US" SNI=\"",
1257 string_printing(tls_in.sni), US"\"");
1262 if (sizep) *sizep = size;
1263 if (ptrp) *ptrp = ptr;
1269 /*************************************************
1270 * Log lack of MAIL if so configured *
1271 *************************************************/
1273 /* This function is called when an SMTP session ends. If the log selector
1274 smtp_no_mail is set, write a log line giving some details of what has happened
1275 in the SMTP session.
1282 smtp_log_no_mail(void)
1287 if (smtp_mailcmd_count > 0 || (log_extra_selector & LX_smtp_no_mail) == 0)
1293 if (sender_host_authenticated != NULL)
1295 s = string_append(s, &size, &ptr, 2, US" A=", sender_host_authenticated);
1296 if (authenticated_id != NULL)
1297 s = string_append(s, &size, &ptr, 2, US":", authenticated_id);
1301 s = s_tlslog(s, &size, &ptr);
1304 sep = (smtp_connection_had[SMTP_HBUFF_SIZE-1] != SCH_NONE)?
1305 US" C=..." : US" C=";
1306 for (i = smtp_ch_index; i < SMTP_HBUFF_SIZE; i++)
1308 if (smtp_connection_had[i] != SCH_NONE)
1310 s = string_append(s, &size, &ptr, 2, sep,
1311 smtp_names[smtp_connection_had[i]]);
1316 for (i = 0; i < smtp_ch_index; i++)
1318 s = string_append(s, &size, &ptr, 2, sep, smtp_names[smtp_connection_had[i]]);
1322 if (s != NULL) s[ptr] = 0; else s = US"";
1323 log_write(0, LOG_MAIN, "no MAIL in SMTP connection from %s D=%s%s",
1324 host_and_ident(FALSE),
1325 readconf_printtime( (int) ((long)time(NULL) - (long)smtp_connection_start)),
1331 /*************************************************
1332 * Check HELO line and set sender_helo_name *
1333 *************************************************/
1335 /* Check the format of a HELO line. The data for HELO/EHLO is supposed to be
1336 the domain name of the sending host, or an ip literal in square brackets. The
1337 arrgument is placed in sender_helo_name, which is in malloc store, because it
1338 must persist over multiple incoming messages. If helo_accept_junk is set, this
1339 host is permitted to send any old junk (needed for some broken hosts).
1340 Otherwise, helo_allow_chars can be used for rogue characters in general
1341 (typically people want to let in underscores).
1344 s the data portion of the line (already past any white space)
1346 Returns: TRUE or FALSE
1350 check_helo(uschar *s)
1353 uschar *end = s + Ustrlen(s);
1354 BOOL yield = helo_accept_junk;
1356 /* Discard any previous helo name */
1358 if (sender_helo_name != NULL)
1360 store_free(sender_helo_name);
1361 sender_helo_name = NULL;
1364 /* Skip tests if junk is permitted. */
1368 /* Allow the new standard form for IPv6 address literals, namely,
1369 [IPv6:....], and because someone is bound to use it, allow an equivalent
1370 IPv4 form. Allow plain addresses as well. */
1377 if (strncmpic(s, US"[IPv6:", 6) == 0)
1378 yield = (string_is_ip_address(s+6, NULL) == 6);
1379 else if (strncmpic(s, US"[IPv4:", 6) == 0)
1380 yield = (string_is_ip_address(s+6, NULL) == 4);
1382 yield = (string_is_ip_address(s+1, NULL) != 0);
1387 /* Non-literals must be alpha, dot, hyphen, plus any non-valid chars
1388 that have been configured (usually underscore - sigh). */
1395 if (!isalnum(*s) && *s != '.' && *s != '-' &&
1396 Ustrchr(helo_allow_chars, *s) == NULL)
1406 /* Save argument if OK */
1408 if (yield) sender_helo_name = string_copy_malloc(start);
1416 /*************************************************
1417 * Extract SMTP command option *
1418 *************************************************/
1420 /* This function picks the next option setting off the end of smtp_cmd_data. It
1421 is called for MAIL FROM and RCPT TO commands, to pick off the optional ESMTP
1422 things that can appear there.
1425 name point this at the name
1426 value point this at the data string
1428 Returns: TRUE if found an option
1432 extract_option(uschar **name, uschar **value)
1435 uschar *v = smtp_cmd_data + Ustrlen(smtp_cmd_data) - 1;
1436 while (isspace(*v)) v--;
1438 while (v > smtp_cmd_data && *v != '=' && !isspace(*v)) v--;
1443 while(isalpha(n[-1])) n--;
1444 /* RFC says SP, but TAB seen in wild and other major MTAs accept it */
1445 if (!isspace(n[-1])) return FALSE;
1451 if (v == smtp_cmd_data) return FALSE;
1463 /*************************************************
1464 * Reset for new message *
1465 *************************************************/
1467 /* This function is called whenever the SMTP session is reset from
1468 within either of the setup functions.
1470 Argument: the stacking pool storage reset point
1475 smtp_reset(void *reset_point)
1477 store_reset(reset_point);
1478 recipients_list = NULL;
1479 rcpt_count = rcpt_defer_count = rcpt_fail_count =
1480 raw_recipients_count = recipients_count = recipients_list_max = 0;
1481 cancel_cutthrough_connection("smtp reset");
1482 message_linecount = 0;
1484 acl_added_headers = NULL;
1485 acl_removed_headers = NULL;
1486 queue_only_policy = FALSE;
1487 rcpt_smtp_response = NULL;
1488 rcpt_smtp_response_same = TRUE;
1489 rcpt_in_progress = FALSE;
1490 deliver_freeze = FALSE; /* Can be set by ACL */
1491 freeze_tell = freeze_tell_config; /* Can be set by ACL */
1492 fake_response = OK; /* Can be set by ACL */
1493 #ifdef WITH_CONTENT_SCAN
1494 no_mbox_unspool = FALSE; /* Can be set by ACL */
1496 submission_mode = FALSE; /* Can be set by ACL */
1497 suppress_local_fixups = suppress_local_fixups_default; /* Can be set by ACL */
1498 active_local_from_check = local_from_check; /* Can be set by ACL */
1499 active_local_sender_retain = local_sender_retain; /* Can be set by ACL */
1500 sender_address = NULL;
1501 submission_name = NULL; /* Can be set by ACL */
1502 raw_sender = NULL; /* After SMTP rewrite, before qualifying */
1503 sender_address_unrewritten = NULL; /* Set only after verify rewrite */
1504 sender_verified_list = NULL; /* No senders verified */
1505 memset(sender_address_cache, 0, sizeof(sender_address_cache));
1506 memset(sender_domain_cache, 0, sizeof(sender_domain_cache));
1508 prdr_requested = FALSE;
1510 /* Reset the DSN flags */
1514 authenticated_sender = NULL;
1515 #ifdef EXPERIMENTAL_BRIGHTMAIL
1517 bmi_verdicts = NULL;
1519 #ifndef DISABLE_DKIM
1520 dkim_signers = NULL;
1521 dkim_disable_verify = FALSE;
1522 dkim_collect_input = FALSE;
1524 #ifdef EXPERIMENTAL_SPF
1525 spf_header_comment = NULL;
1526 spf_received = NULL;
1528 spf_smtp_comment = NULL;
1530 #ifdef EXPERIMENTAL_INTERNATIONAL
1531 message_smtputf8 = FALSE;
1533 body_linecount = body_zerocount = 0;
1535 sender_rate = sender_rate_limit = sender_rate_period = NULL;
1536 ratelimiters_mail = NULL; /* Updated by ratelimit ACL condition */
1537 /* Note that ratelimiters_conn persists across resets. */
1539 /* Reset message ACL variables */
1543 /* The message body variables use malloc store. They may be set if this is
1544 not the first message in an SMTP session and the previous message caused them
1545 to be referenced in an ACL. */
1547 if (message_body != NULL)
1549 store_free(message_body);
1550 message_body = NULL;
1553 if (message_body_end != NULL)
1555 store_free(message_body_end);
1556 message_body_end = NULL;
1559 /* Warning log messages are also saved in malloc store. They are saved to avoid
1560 repetition in the same message, but it seems right to repeat them for different
1563 while (acl_warn_logged != NULL)
1565 string_item *this = acl_warn_logged;
1566 acl_warn_logged = acl_warn_logged->next;
1575 /*************************************************
1576 * Initialize for incoming batched SMTP message *
1577 *************************************************/
1579 /* This function is called from smtp_setup_msg() in the case when
1580 smtp_batched_input is true. This happens when -bS is used to pass a whole batch
1581 of messages in one file with SMTP commands between them. All errors must be
1582 reported by sending a message, and only MAIL FROM, RCPT TO, and DATA are
1583 relevant. After an error on a sender, or an invalid recipient, the remainder
1584 of the message is skipped. The value of received_protocol is already set.
1587 Returns: > 0 message successfully started (reached DATA)
1588 = 0 QUIT read or end of file reached
1589 < 0 should not occur
1593 smtp_setup_batch_msg(void)
1596 void *reset_point = store_get(0);
1598 /* Save the line count at the start of each transaction - single commands
1599 like HELO and RSET count as whole transactions. */
1601 bsmtp_transaction_linecount = receive_linecount;
1603 if ((receive_feof)()) return 0; /* Treat EOF as QUIT */
1605 smtp_reset(reset_point); /* Reset for start of message */
1607 /* Deal with SMTP commands. This loop is exited by setting done to a POSITIVE
1608 value. The values are 2 larger than the required yield of the function. */
1613 uschar *recipient = NULL;
1614 int start, end, sender_domain, recipient_domain;
1616 switch(smtp_read_command(FALSE))
1618 /* The HELO/EHLO commands set sender_address_helo if they have
1619 valid data; otherwise they are ignored, except that they do
1620 a reset of the state. */
1625 check_helo(smtp_cmd_data);
1629 smtp_reset(reset_point);
1630 bsmtp_transaction_linecount = receive_linecount;
1634 /* The MAIL FROM command requires an address as an operand. All we
1635 do here is to parse it for syntactic correctness. The form "<>" is
1636 a special case which converts into an empty string. The start/end
1637 pointers in the original are not used further for this address, as
1638 it is the canonical extracted address which is all that is kept. */
1641 if (sender_address != NULL)
1642 /* The function moan_smtp_batch() does not return. */
1643 moan_smtp_batch(smtp_cmd_buffer, "503 Sender already given");
1645 if (smtp_cmd_data[0] == 0)
1646 /* The function moan_smtp_batch() does not return. */
1647 moan_smtp_batch(smtp_cmd_buffer, "501 MAIL FROM must have an address operand");
1649 /* Reset to start of message */
1651 smtp_reset(reset_point);
1653 /* Apply SMTP rewrite */
1655 raw_sender = ((rewrite_existflags & rewrite_smtp) != 0)?
1656 rewrite_one(smtp_cmd_data, rewrite_smtp|rewrite_smtp_sender, NULL, FALSE,
1657 US"", global_rewrite_rules) : smtp_cmd_data;
1659 /* Extract the address; the TRUE flag allows <> as valid */
1662 parse_extract_address(raw_sender, &errmess, &start, &end, &sender_domain,
1665 if (raw_sender == NULL)
1666 /* The function moan_smtp_batch() does not return. */
1667 moan_smtp_batch(smtp_cmd_buffer, "501 %s", errmess);
1669 sender_address = string_copy(raw_sender);
1671 /* Qualify unqualified sender addresses if permitted to do so. */
1673 if (sender_domain == 0 && sender_address[0] != 0 && sender_address[0] != '@')
1675 if (allow_unqualified_sender)
1677 sender_address = rewrite_address_qualify(sender_address, FALSE);
1678 DEBUG(D_receive) debug_printf("unqualified address %s accepted "
1679 "and rewritten\n", raw_sender);
1681 /* The function moan_smtp_batch() does not return. */
1682 else moan_smtp_batch(smtp_cmd_buffer, "501 sender address must contain "
1688 /* The RCPT TO command requires an address as an operand. All we do
1689 here is to parse it for syntactic correctness. There may be any number
1690 of RCPT TO commands, specifying multiple senders. We build them all into
1691 a data structure that is in argc/argv format. The start/end values
1692 given by parse_extract_address are not used, as we keep only the
1693 extracted address. */
1696 if (sender_address == NULL)
1697 /* The function moan_smtp_batch() does not return. */
1698 moan_smtp_batch(smtp_cmd_buffer, "503 No sender yet given");
1700 if (smtp_cmd_data[0] == 0)
1701 /* The function moan_smtp_batch() does not return. */
1702 moan_smtp_batch(smtp_cmd_buffer, "501 RCPT TO must have an address operand");
1704 /* Check maximum number allowed */
1706 if (recipients_max > 0 && recipients_count + 1 > recipients_max)
1707 /* The function moan_smtp_batch() does not return. */
1708 moan_smtp_batch(smtp_cmd_buffer, "%s too many recipients",
1709 recipients_max_reject? "552": "452");
1711 /* Apply SMTP rewrite, then extract address. Don't allow "<>" as a
1712 recipient address */
1714 recipient = ((rewrite_existflags & rewrite_smtp) != 0)?
1715 rewrite_one(smtp_cmd_data, rewrite_smtp, NULL, FALSE, US"",
1716 global_rewrite_rules) : smtp_cmd_data;
1718 /* rfc821_domains = TRUE; << no longer needed */
1719 recipient = parse_extract_address(recipient, &errmess, &start, &end,
1720 &recipient_domain, FALSE);
1721 /* rfc821_domains = FALSE; << no longer needed */
1723 if (recipient == NULL)
1724 /* The function moan_smtp_batch() does not return. */
1725 moan_smtp_batch(smtp_cmd_buffer, "501 %s", errmess);
1727 /* If the recipient address is unqualified, qualify it if permitted. Then
1728 add it to the list of recipients. */
1730 if (recipient_domain == 0)
1732 if (allow_unqualified_recipient)
1734 DEBUG(D_receive) debug_printf("unqualified address %s accepted\n",
1736 recipient = rewrite_address_qualify(recipient, TRUE);
1738 /* The function moan_smtp_batch() does not return. */
1739 else moan_smtp_batch(smtp_cmd_buffer, "501 recipient address must contain "
1742 receive_add_recipient(recipient, -1);
1746 /* The DATA command is legal only if it follows successful MAIL FROM
1747 and RCPT TO commands. This function is complete when a valid DATA
1748 command is encountered. */
1751 if (sender_address == NULL || recipients_count <= 0)
1753 /* The function moan_smtp_batch() does not return. */
1754 if (sender_address == NULL)
1755 moan_smtp_batch(smtp_cmd_buffer,
1756 "503 MAIL FROM:<sender> command must precede DATA");
1758 moan_smtp_batch(smtp_cmd_buffer,
1759 "503 RCPT TO:<recipient> must precede DATA");
1763 done = 3; /* DATA successfully achieved */
1764 message_ended = END_NOTENDED; /* Indicate in middle of message */
1769 /* The VRFY, EXPN, HELP, ETRN, and NOOP commands are ignored. */
1776 bsmtp_transaction_linecount = receive_linecount;
1787 /* The function moan_smtp_batch() does not return. */
1788 moan_smtp_batch(smtp_cmd_buffer, "501 Unexpected argument data");
1793 /* The function moan_smtp_batch() does not return. */
1794 moan_smtp_batch(smtp_cmd_buffer, "501 Unexpected NULL in SMTP command");
1799 /* The function moan_smtp_batch() does not return. */
1800 moan_smtp_batch(smtp_cmd_buffer, "500 Command unrecognized");
1805 return done - 2; /* Convert yield values */
1811 /*************************************************
1812 * Start an SMTP session *
1813 *************************************************/
1815 /* This function is called at the start of an SMTP session. Thereafter,
1816 smtp_setup_msg() is called to initiate each separate message. This
1817 function does host-specific testing, and outputs the banner line.
1820 Returns: FALSE if the session can not continue; something has
1821 gone wrong, or the connection to the host is blocked
1825 smtp_start_session(void)
1829 uschar *user_msg, *log_msg;
1833 smtp_connection_start = time(NULL);
1834 for (smtp_ch_index = 0; smtp_ch_index < SMTP_HBUFF_SIZE; smtp_ch_index++)
1835 smtp_connection_had[smtp_ch_index] = SCH_NONE;
1838 /* Default values for certain variables */
1840 helo_seen = esmtp = helo_accept_junk = FALSE;
1841 smtp_mailcmd_count = 0;
1842 count_nonmail = TRUE_UNSET;
1843 synprot_error_count = unknown_command_count = nonmail_command_count = 0;
1844 smtp_delay_mail = smtp_rlm_base;
1845 auth_advertised = FALSE;
1846 pipelining_advertised = FALSE;
1847 pipelining_enable = TRUE;
1848 sync_cmd_limit = NON_SYNC_CMD_NON_PIPELINING;
1849 smtp_exit_function_called = FALSE; /* For avoiding loop in not-quit exit */
1851 memset(sender_host_cache, 0, sizeof(sender_host_cache));
1853 /* If receiving by -bs from a trusted user, or testing with -bh, we allow
1854 authentication settings from -oMaa to remain in force. */
1856 if (!host_checking && !sender_host_notsocket) sender_host_authenticated = NULL;
1857 authenticated_by = NULL;
1860 tls_in.cipher = tls_in.peerdn = NULL;
1861 tls_in.ourcert = tls_in.peercert = NULL;
1863 tls_in.ocsp = OCSP_NOT_REQ;
1864 tls_advertised = FALSE;
1866 dsn_advertised = FALSE;
1867 #ifdef EXPERIMENTAL_INTERNATIONAL
1868 smtputf8_advertised = FALSE;
1871 /* Reset ACL connection variables */
1875 /* Allow for trailing 0 in the command and data buffers. */
1877 smtp_cmd_buffer = (uschar *)malloc(2*smtp_cmd_buffer_size + 2);
1878 if (smtp_cmd_buffer == NULL)
1879 log_write(0, LOG_MAIN|LOG_PANIC_DIE,
1880 "malloc() failed for SMTP command buffer");
1881 smtp_cmd_buffer[0] = 0;
1882 smtp_data_buffer = smtp_cmd_buffer + smtp_cmd_buffer_size + 1;
1884 /* For batched input, the protocol setting can be overridden from the
1885 command line by a trusted caller. */
1887 if (smtp_batched_input)
1889 if (received_protocol == NULL) received_protocol = US"local-bsmtp";
1892 /* For non-batched SMTP input, the protocol setting is forced here. It will be
1893 reset later if any of EHLO/AUTH/STARTTLS are received. */
1897 protocols[pnormal] + ((sender_host_address != NULL)? pnlocal : 0);
1899 /* Set up the buffer for inputting using direct read() calls, and arrange to
1900 call the local functions instead of the standard C ones. */
1902 smtp_inbuffer = (uschar *)malloc(in_buffer_size);
1903 if (smtp_inbuffer == NULL)
1904 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "malloc() failed for SMTP input buffer");
1905 receive_getc = smtp_getc;
1906 receive_ungetc = smtp_ungetc;
1907 receive_feof = smtp_feof;
1908 receive_ferror = smtp_ferror;
1909 receive_smtp_buffered = smtp_buffered;
1910 smtp_inptr = smtp_inend = smtp_inbuffer;
1911 smtp_had_eof = smtp_had_error = 0;
1913 /* Set up the message size limit; this may be host-specific */
1915 thismessage_size_limit = expand_string_integer(message_size_limit, TRUE);
1916 if (expand_string_message != NULL)
1918 if (thismessage_size_limit == -1)
1919 log_write(0, LOG_MAIN|LOG_PANIC, "unable to expand message_size_limit: "
1920 "%s", expand_string_message);
1922 log_write(0, LOG_MAIN|LOG_PANIC, "invalid message_size_limit: "
1923 "%s", expand_string_message);
1924 smtp_closedown(US"Temporary local problem - please try later");
1928 /* When a message is input locally via the -bs or -bS options, sender_host_
1929 unknown is set unless -oMa was used to force an IP address, in which case it
1930 is checked like a real remote connection. When -bs is used from inetd, this
1931 flag is not set, causing the sending host to be checked. The code that deals
1932 with IP source routing (if configured) is never required for -bs or -bS and
1933 the flag sender_host_notsocket is used to suppress it.
1935 If smtp_accept_max and smtp_accept_reserve are set, keep some connections in
1936 reserve for certain hosts and/or networks. */
1938 if (!sender_host_unknown)
1941 BOOL reserved_host = FALSE;
1943 /* Look up IP options (source routing info) on the socket if this is not an
1944 -oMa "host", and if any are found, log them and drop the connection.
1946 Linux (and others now, see below) is different to everyone else, so there
1947 has to be some conditional compilation here. Versions of Linux before 2.1.15
1948 used a structure whose name was "options". Somebody finally realized that
1949 this name was silly, and it got changed to "ip_options". I use the
1950 newer name here, but there is a fudge in the script that sets up os.h
1951 to define a macro in older Linux systems.
1953 Sigh. Linux is a fast-moving target. Another generation of Linux uses
1954 glibc 2, which has chosen ip_opts for the structure name. This is now
1955 really a glibc thing rather than a Linux thing, so the condition name
1956 has been changed to reflect this. It is relevant also to GNU/Hurd.
1958 Mac OS 10.x (Darwin) is like the later glibc versions, but without the
1959 setting of the __GLIBC__ macro, so we can't detect it automatically. There's
1960 a special macro defined in the os.h file.
1962 Some DGUX versions on older hardware appear not to support IP options at
1963 all, so there is now a general macro which can be set to cut out this
1966 How to do this properly in IPv6 is not yet known. */
1968 #if !HAVE_IPV6 && !defined(NO_IP_OPTIONS)
1970 #ifdef GLIBC_IP_OPTIONS
1971 #if (!defined __GLIBC__) || (__GLIBC__ < 2)
1976 #elif defined DARWIN_IP_OPTIONS
1982 if (!host_checking && !sender_host_notsocket)
1985 EXIM_SOCKLEN_T optlen = sizeof(struct ip_options) + MAX_IPOPTLEN;
1986 struct ip_options *ipopt = store_get(optlen);
1988 struct ip_opts ipoptblock;
1989 struct ip_opts *ipopt = &ipoptblock;
1990 EXIM_SOCKLEN_T optlen = sizeof(ipoptblock);
1992 struct ipoption ipoptblock;
1993 struct ipoption *ipopt = &ipoptblock;
1994 EXIM_SOCKLEN_T optlen = sizeof(ipoptblock);
1997 /* Occasional genuine failures of getsockopt() have been seen - for
1998 example, "reset by peer". Therefore, just log and give up on this
1999 call, unless the error is ENOPROTOOPT. This error is given by systems
2000 that have the interfaces but not the mechanism - e.g. GNU/Hurd at the time
2001 of writing. So for that error, carry on - we just can't do an IP options
2004 DEBUG(D_receive) debug_printf("checking for IP options\n");
2006 if (getsockopt(fileno(smtp_out), IPPROTO_IP, IP_OPTIONS, (uschar *)(ipopt),
2009 if (errno != ENOPROTOOPT)
2011 log_write(0, LOG_MAIN, "getsockopt() failed from %s: %s",
2012 host_and_ident(FALSE), strerror(errno));
2013 smtp_printf("451 SMTP service not available\r\n");
2018 /* Deal with any IP options that are set. On the systems I have looked at,
2019 the value of MAX_IPOPTLEN has been 40, meaning that there should never be
2020 more logging data than will fit in big_buffer. Nevertheless, after somebody
2021 questioned this code, I've added in some paranoid checking. */
2023 else if (optlen > 0)
2025 uschar *p = big_buffer;
2026 uschar *pend = big_buffer + big_buffer_size;
2027 uschar *opt, *adptr;
2029 struct in_addr addr;
2032 uschar *optstart = (uschar *)(ipopt->__data);
2034 uschar *optstart = (uschar *)(ipopt->ip_opts);
2036 uschar *optstart = (uschar *)(ipopt->ipopt_list);
2039 DEBUG(D_receive) debug_printf("IP options exist\n");
2041 Ustrcpy(p, "IP options on incoming call:");
2044 for (opt = optstart; opt != NULL &&
2045 opt < (uschar *)(ipopt) + optlen;)
2059 if (!string_format(p, pend-p, " %s [@%s",
2060 (*opt == IPOPT_SSRR)? "SSRR" : "LSRR",
2062 inet_ntoa(*((struct in_addr *)(&(ipopt->faddr))))))
2064 inet_ntoa(ipopt->ip_dst)))
2066 inet_ntoa(ipopt->ipopt_dst)))
2074 optcount = (opt[1] - 3) / sizeof(struct in_addr);
2076 while (optcount-- > 0)
2078 memcpy(&addr, adptr, sizeof(addr));
2079 if (!string_format(p, pend - p - 1, "%s%s",
2080 (optcount == 0)? ":" : "@", inet_ntoa(addr)))
2086 adptr += sizeof(struct in_addr);
2095 if (pend - p < 4 + 3*opt[1]) { opt = NULL; break; }
2098 for (i = 0; i < opt[1]; i++)
2100 sprintf(CS p, "%2.2x ", opt[i]);
2111 log_write(0, LOG_MAIN, "%s", big_buffer);
2113 /* Refuse any call with IP options. This is what tcpwrappers 7.5 does. */
2115 log_write(0, LOG_MAIN|LOG_REJECT,
2116 "connection from %s refused (IP options)", host_and_ident(FALSE));
2118 smtp_printf("554 SMTP service not available\r\n");
2122 /* Length of options = 0 => there are no options */
2124 else DEBUG(D_receive) debug_printf("no IP options found\n");
2126 #endif /* HAVE_IPV6 && !defined(NO_IP_OPTIONS) */
2128 /* Set keep-alive in socket options. The option is on by default. This
2129 setting is an attempt to get rid of some hanging connections that stick in
2130 read() when the remote end (usually a dialup) goes away. */
2132 if (smtp_accept_keepalive && !sender_host_notsocket)
2133 ip_keepalive(fileno(smtp_out), sender_host_address, FALSE);
2135 /* If the current host matches host_lookup, set the name by doing a
2136 reverse lookup. On failure, sender_host_name will be NULL and
2137 host_lookup_failed will be TRUE. This may or may not be serious - optional
2140 if (verify_check_host(&host_lookup) == OK)
2142 (void)host_name_lookup();
2143 host_build_sender_fullhost();
2146 /* Delay this until we have the full name, if it is looked up. */
2148 set_process_info("handling incoming connection from %s",
2149 host_and_ident(FALSE));
2151 /* Expand smtp_receive_timeout, if needed */
2153 if (smtp_receive_timeout_s)
2156 if ( !(exp = expand_string(smtp_receive_timeout_s))
2158 || (smtp_receive_timeout = readconf_readtime(exp, 0, FALSE)) < 0
2160 log_write(0, LOG_MAIN|LOG_PANIC,
2161 "bad value for smtp_receive_timeout: '%s'", exp ? exp : US"");
2164 /* Start up TLS if tls_on_connect is set. This is for supporting the legacy
2165 smtps port for use with older style SSL MTAs. */
2168 if (tls_in.on_connect && tls_server_start(tls_require_ciphers) != OK)
2172 /* Test for explicit connection rejection */
2174 if (verify_check_host(&host_reject_connection) == OK)
2176 log_write(L_connection_reject, LOG_MAIN|LOG_REJECT, "refused connection "
2177 "from %s (host_reject_connection)", host_and_ident(FALSE));
2178 smtp_printf("554 SMTP service not available\r\n");
2182 /* Test with TCP Wrappers if so configured. There is a problem in that
2183 hosts_ctl() returns 0 (deny) under a number of system failure circumstances,
2184 such as disks dying. In these cases, it is desirable to reject with a 4xx
2185 error instead of a 5xx error. There isn't a "right" way to detect such
2186 problems. The following kludge is used: errno is zeroed before calling
2187 hosts_ctl(). If the result is "reject", a 5xx error is given only if the
2188 value of errno is 0 or ENOENT (which happens if /etc/hosts.{allow,deny} does
2191 #ifdef USE_TCP_WRAPPERS
2193 tcp_wrappers_name = expand_string(tcp_wrappers_daemon_name);
2194 if (tcp_wrappers_name == NULL)
2196 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "Expansion of \"%s\" "
2197 "(tcp_wrappers_name) failed: %s", string_printing(tcp_wrappers_name),
2198 expand_string_message);
2200 if (!hosts_ctl(tcp_wrappers_name,
2201 (sender_host_name == NULL)? STRING_UNKNOWN : CS sender_host_name,
2202 (sender_host_address == NULL)? STRING_UNKNOWN : CS sender_host_address,
2203 (sender_ident == NULL)? STRING_UNKNOWN : CS sender_ident))
2205 if (errno == 0 || errno == ENOENT)
2207 HDEBUG(D_receive) debug_printf("tcp wrappers rejection\n");
2208 log_write(L_connection_reject,
2209 LOG_MAIN|LOG_REJECT, "refused connection from %s "
2210 "(tcp wrappers)", host_and_ident(FALSE));
2211 smtp_printf("554 SMTP service not available\r\n");
2215 int save_errno = errno;
2216 HDEBUG(D_receive) debug_printf("tcp wrappers rejected with unexpected "
2217 "errno value %d\n", save_errno);
2218 log_write(L_connection_reject,
2219 LOG_MAIN|LOG_REJECT, "temporarily refused connection from %s "
2220 "(tcp wrappers errno=%d)", host_and_ident(FALSE), save_errno);
2221 smtp_printf("451 Temporary local problem - please try later\r\n");
2227 /* Check for reserved slots. The value of smtp_accept_count has already been
2228 incremented to include this process. */
2230 if (smtp_accept_max > 0 &&
2231 smtp_accept_count > smtp_accept_max - smtp_accept_reserve)
2233 if ((rc = verify_check_host(&smtp_reserve_hosts)) != OK)
2235 log_write(L_connection_reject,
2236 LOG_MAIN, "temporarily refused connection from %s: not in "
2237 "reserve list: connected=%d max=%d reserve=%d%s",
2238 host_and_ident(FALSE), smtp_accept_count - 1, smtp_accept_max,
2239 smtp_accept_reserve, (rc == DEFER)? " (lookup deferred)" : "");
2240 smtp_printf("421 %s: Too many concurrent SMTP connections; "
2241 "please try again later\r\n", smtp_active_hostname);
2244 reserved_host = TRUE;
2247 /* If a load level above which only messages from reserved hosts are
2248 accepted is set, check the load. For incoming calls via the daemon, the
2249 check is done in the superior process if there are no reserved hosts, to
2250 save a fork. In all cases, the load average will already be available
2251 in a global variable at this point. */
2253 if (smtp_load_reserve >= 0 &&
2254 load_average > smtp_load_reserve &&
2256 verify_check_host(&smtp_reserve_hosts) != OK)
2258 log_write(L_connection_reject,
2259 LOG_MAIN, "temporarily refused connection from %s: not in "
2260 "reserve list and load average = %.2f", host_and_ident(FALSE),
2261 (double)load_average/1000.0);
2262 smtp_printf("421 %s: Too much load; please try again later\r\n",
2263 smtp_active_hostname);
2267 /* Determine whether unqualified senders or recipients are permitted
2268 for this host. Unfortunately, we have to do this every time, in order to
2269 set the flags so that they can be inspected when considering qualifying
2270 addresses in the headers. For a site that permits no qualification, this
2271 won't take long, however. */
2273 allow_unqualified_sender =
2274 verify_check_host(&sender_unqualified_hosts) == OK;
2276 allow_unqualified_recipient =
2277 verify_check_host(&recipient_unqualified_hosts) == OK;
2279 /* Determine whether HELO/EHLO is required for this host. The requirement
2280 can be hard or soft. */
2282 helo_required = verify_check_host(&helo_verify_hosts) == OK;
2284 helo_verify = verify_check_host(&helo_try_verify_hosts) == OK;
2286 /* Determine whether this hosts is permitted to send syntactic junk
2287 after a HELO or EHLO command. */
2289 helo_accept_junk = verify_check_host(&helo_accept_junk_hosts) == OK;
2292 /* For batch SMTP input we are now done. */
2294 if (smtp_batched_input) return TRUE;
2296 #ifdef EXPERIMENTAL_PROXY
2297 /* If valid Proxy Protocol source is connecting, set up session.
2298 * Failure will not allow any SMTP function other than QUIT. */
2299 proxy_session = FALSE;
2300 proxy_session_failed = FALSE;
2301 if (check_proxy_protocol_host())
2303 if (setup_proxy_protocol_host() == FALSE)
2305 proxy_session_failed = TRUE;
2307 debug_printf("Failure to extract proxied host, only QUIT allowed\n");
2311 sender_host_name = NULL;
2312 (void)host_name_lookup();
2313 host_build_sender_fullhost();
2318 /* Run the ACL if it exists */
2321 if (acl_smtp_connect != NULL)
2324 rc = acl_check(ACL_WHERE_CONNECT, NULL, acl_smtp_connect, &user_msg,
2328 (void)smtp_handle_acl_fail(ACL_WHERE_CONNECT, rc, user_msg, log_msg);
2333 /* Output the initial message for a two-way SMTP connection. It may contain
2334 newlines, which then cause a multi-line response to be given. */
2336 code = US"220"; /* Default status code */
2337 esc = US""; /* Default extended status code */
2338 esclen = 0; /* Length of esc */
2340 if (user_msg == NULL)
2342 s = expand_string(smtp_banner);
2344 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "Expansion of \"%s\" (smtp_banner) "
2345 "failed: %s", smtp_banner, expand_string_message);
2351 smtp_message_code(&code, &codelen, &s, NULL);
2355 esclen = codelen - 4;
2359 /* Remove any terminating newlines; might as well remove trailing space too */
2362 while (p > s && isspace(p[-1])) p--;
2365 /* It seems that CC:Mail is braindead, and assumes that the greeting message
2366 is all contained in a single IP packet. The original code wrote out the
2367 greeting using several calls to fprint/fputc, and on busy servers this could
2368 cause it to be split over more than one packet - which caused CC:Mail to fall
2369 over when it got the second part of the greeting after sending its first
2370 command. Sigh. To try to avoid this, build the complete greeting message
2371 first, and output it in one fell swoop. This gives a better chance of it
2372 ending up as a single packet. */
2374 ss = store_get(size);
2378 do /* At least once, in case we have an empty string */
2381 uschar *linebreak = Ustrchr(p, '\n');
2382 ss = string_cat(ss, &size, &ptr, code, 3);
2383 if (linebreak == NULL)
2386 ss = string_cat(ss, &size, &ptr, US" ", 1);
2390 len = linebreak - p;
2391 ss = string_cat(ss, &size, &ptr, US"-", 1);
2393 ss = string_cat(ss, &size, &ptr, esc, esclen);
2394 ss = string_cat(ss, &size, &ptr, p, len);
2395 ss = string_cat(ss, &size, &ptr, US"\r\n", 2);
2397 if (linebreak != NULL) p++;
2401 ss[ptr] = 0; /* string_cat leaves room for this */
2403 /* Before we write the banner, check that there is no input pending, unless
2404 this synchronisation check is disabled. */
2408 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP protocol "
2409 "synchronization error (input sent without waiting for greeting): "
2410 "rejected connection from %s input=\"%s\"", host_and_ident(TRUE),
2411 string_printing(smtp_inptr));
2412 smtp_printf("554 SMTP synchronization error\r\n");
2416 /* Now output the banner */
2418 smtp_printf("%s", ss);
2426 /*************************************************
2427 * Handle SMTP syntax and protocol errors *
2428 *************************************************/
2430 /* Write to the log for SMTP syntax errors in incoming commands, if configured
2431 to do so. Then transmit the error response. The return value depends on the
2432 number of syntax and protocol errors in this SMTP session.
2435 type error type, given as a log flag bit
2436 code response code; <= 0 means don't send a response
2437 data data to reflect in the response (can be NULL)
2438 errmess the error message
2440 Returns: -1 limit of syntax/protocol errors NOT exceeded
2441 +1 limit of syntax/protocol errors IS exceeded
2443 These values fit in with the values of the "done" variable in the main
2444 processing loop in smtp_setup_msg(). */
2447 synprot_error(int type, int code, uschar *data, uschar *errmess)
2451 log_write(type, LOG_MAIN, "SMTP %s error in \"%s\" %s %s",
2452 (type == L_smtp_syntax_error)? "syntax" : "protocol",
2453 string_printing(smtp_cmd_buffer), host_and_ident(TRUE), errmess);
2455 if (++synprot_error_count > smtp_max_synprot_errors)
2458 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
2459 "syntax or protocol errors (last command was \"%s\")",
2460 host_and_ident(FALSE), smtp_cmd_buffer);
2465 smtp_printf("%d%c%s%s%s\r\n", code, (yield == 1)? '-' : ' ',
2466 (data == NULL)? US"" : data, (data == NULL)? US"" : US": ", errmess);
2468 smtp_printf("%d Too many syntax or protocol errors\r\n", code);
2477 /*************************************************
2478 * Log incomplete transactions *
2479 *************************************************/
2481 /* This function is called after a transaction has been aborted by RSET, QUIT,
2482 connection drops or other errors. It logs the envelope information received
2483 so far in order to preserve address verification attempts.
2485 Argument: string to indicate what aborted the transaction
2490 incomplete_transaction_log(uschar *what)
2492 if (sender_address == NULL || /* No transaction in progress */
2493 (log_write_selector & L_smtp_incomplete_transaction) == 0 /* Not logging */
2496 /* Build list of recipients for logging */
2498 if (recipients_count > 0)
2501 raw_recipients = store_get(recipients_count * sizeof(uschar *));
2502 for (i = 0; i < recipients_count; i++)
2503 raw_recipients[i] = recipients_list[i].address;
2504 raw_recipients_count = recipients_count;
2507 log_write(L_smtp_incomplete_transaction, LOG_MAIN|LOG_SENDER|LOG_RECIPIENTS,
2508 "%s incomplete transaction (%s)", host_and_ident(TRUE), what);
2514 /*************************************************
2515 * Send SMTP response, possibly multiline *
2516 *************************************************/
2518 /* There are, it seems, broken clients out there that cannot handle multiline
2519 responses. If no_multiline_responses is TRUE (it can be set from an ACL), we
2520 output nothing for non-final calls, and only the first line for anything else.
2523 code SMTP code, may involve extended status codes
2524 codelen length of smtp code; if > 4 there's an ESC
2525 final FALSE if the last line isn't the final line
2526 msg message text, possibly containing newlines
2532 smtp_respond(uschar* code, int codelen, BOOL final, uschar *msg)
2537 if (!final && no_multiline_responses) return;
2542 esclen = codelen - 4;
2545 /* If this is the first output for a (non-batch) RCPT command, see if all RCPTs
2546 have had the same. Note: this code is also present in smtp_printf(). It would
2547 be tidier to have it only in one place, but when it was added, it was easier to
2548 do it that way, so as not to have to mess with the code for the RCPT command,
2549 which sometimes uses smtp_printf() and sometimes smtp_respond(). */
2551 if (rcpt_in_progress)
2553 if (rcpt_smtp_response == NULL)
2554 rcpt_smtp_response = string_copy(msg);
2555 else if (rcpt_smtp_response_same &&
2556 Ustrcmp(rcpt_smtp_response, msg) != 0)
2557 rcpt_smtp_response_same = FALSE;
2558 rcpt_in_progress = FALSE;
2561 /* Not output the message, splitting it up into multiple lines if necessary. */
2565 uschar *nl = Ustrchr(msg, '\n');
2568 smtp_printf("%.3s%c%.*s%s\r\n", code, final? ' ':'-', esclen, esc, msg);
2571 else if (nl[1] == 0 || no_multiline_responses)
2573 smtp_printf("%.3s%c%.*s%.*s\r\n", code, final? ' ':'-', esclen, esc,
2574 (int)(nl - msg), msg);
2579 smtp_printf("%.3s-%.*s%.*s\r\n", code, esclen, esc, (int)(nl - msg), msg);
2581 while (isspace(*msg)) msg++;
2589 /*************************************************
2590 * Parse user SMTP message *
2591 *************************************************/
2593 /* This function allows for user messages overriding the response code details
2594 by providing a suitable response code string at the start of the message
2595 user_msg. Check the message for starting with a response code and optionally an
2596 extended status code. If found, check that the first digit is valid, and if so,
2597 change the code pointer and length to use the replacement. An invalid code
2598 causes a panic log; in this case, if the log messages is the same as the user
2599 message, we must also adjust the value of the log message to show the code that
2600 is actually going to be used (the original one).
2602 This function is global because it is called from receive.c as well as within
2605 Note that the code length returned includes the terminating whitespace
2606 character, which is always included in the regex match.
2609 code SMTP code, may involve extended status codes
2610 codelen length of smtp code; if > 4 there's an ESC
2612 log_msg optional log message, to be adjusted with the new SMTP code
2618 smtp_message_code(uschar **code, int *codelen, uschar **msg, uschar **log_msg)
2623 if (msg == NULL || *msg == NULL) return;
2625 n = pcre_exec(regex_smtp_code, NULL, CS *msg, Ustrlen(*msg), 0,
2626 PCRE_EOPT, ovector, sizeof(ovector)/sizeof(int));
2629 if ((*msg)[0] != (*code)[0])
2631 log_write(0, LOG_MAIN|LOG_PANIC, "configured error code starts with "
2632 "incorrect digit (expected %c) in \"%s\"", (*code)[0], *msg);
2633 if (log_msg != NULL && *log_msg == *msg)
2634 *log_msg = string_sprintf("%s %s", *code, *log_msg + ovector[1]);
2639 *codelen = ovector[1]; /* Includes final space */
2641 *msg += ovector[1]; /* Chop the code off the message */
2648 /*************************************************
2649 * Handle an ACL failure *
2650 *************************************************/
2652 /* This function is called when acl_check() fails. As well as calls from within
2653 this module, it is called from receive.c for an ACL after DATA. It sorts out
2654 logging the incident, and sets up the error response. A message containing
2655 newlines is turned into a multiline SMTP response, but for logging, only the
2658 There's a table of default permanent failure response codes to use in
2659 globals.c, along with the table of names. VFRY is special. Despite RFC1123 it
2660 defaults disabled in Exim. However, discussion in connection with RFC 821bis
2661 (aka RFC 2821) has concluded that the response should be 252 in the disabled
2662 state, because there are broken clients that try VRFY before RCPT. A 5xx
2663 response should be given only when the address is positively known to be
2664 undeliverable. Sigh. Also, for ETRN, 458 is given on refusal, and for AUTH,
2667 From Exim 4.63, it is possible to override the response code details by
2668 providing a suitable response code string at the start of the message provided
2669 in user_msg. The code's first digit is checked for validity.
2672 where where the ACL was called from
2674 user_msg a message that can be included in an SMTP response
2675 log_msg a message for logging
2677 Returns: 0 in most cases
2678 2 if the failure code was FAIL_DROP, in which case the
2679 SMTP connection should be dropped (this value fits with the
2680 "done" variable in smtp_setup_msg() below)
2684 smtp_handle_acl_fail(int where, int rc, uschar *user_msg, uschar *log_msg)
2686 BOOL drop = rc == FAIL_DROP;
2690 uschar *sender_info = US"";
2692 #ifdef WITH_CONTENT_SCAN
2693 (where == ACL_WHERE_MIME)? US"during MIME ACL checks" :
2695 (where == ACL_WHERE_PREDATA)? US"DATA" :
2696 (where == ACL_WHERE_DATA)? US"after DATA" :
2697 #ifndef DISABLE_PRDR
2698 (where == ACL_WHERE_PRDR)? US"after DATA PRDR" :
2700 (smtp_cmd_data == NULL)?
2701 string_sprintf("%s in \"connect\" ACL", acl_wherenames[where]) :
2702 string_sprintf("%s %s", acl_wherenames[where], smtp_cmd_data);
2704 if (drop) rc = FAIL;
2706 /* Set the default SMTP code, and allow a user message to change it. */
2708 smtp_code = (rc != FAIL)? US"451" : acl_wherecodes[where];
2709 smtp_message_code(&smtp_code, &codelen, &user_msg, &log_msg);
2711 /* We used to have sender_address here; however, there was a bug that was not
2712 updating sender_address after a rewrite during a verify. When this bug was
2713 fixed, sender_address at this point became the rewritten address. I'm not sure
2714 this is what should be logged, so I've changed to logging the unrewritten
2715 address to retain backward compatibility. */
2717 #ifndef WITH_CONTENT_SCAN
2718 if (where == ACL_WHERE_RCPT || where == ACL_WHERE_DATA)
2720 if (where == ACL_WHERE_RCPT || where == ACL_WHERE_DATA || where == ACL_WHERE_MIME)
2723 sender_info = string_sprintf("F=<%s>%s%s%s%s ",
2724 sender_address_unrewritten ? sender_address_unrewritten : sender_address,
2725 sender_host_authenticated ? US" A=" : US"",
2726 sender_host_authenticated ? sender_host_authenticated : US"",
2727 sender_host_authenticated && authenticated_id ? US":" : US"",
2728 sender_host_authenticated && authenticated_id ? authenticated_id : US""
2732 /* If there's been a sender verification failure with a specific message, and
2733 we have not sent a response about it yet, do so now, as a preliminary line for
2734 failures, but not defers. However, always log it for defer, and log it for fail
2735 unless the sender_verify_fail log selector has been turned off. */
2737 if (sender_verified_failed != NULL &&
2738 !testflag(sender_verified_failed, af_sverify_told))
2740 BOOL save_rcpt_in_progress = rcpt_in_progress;
2741 rcpt_in_progress = FALSE; /* So as not to treat these as the error */
2743 setflag(sender_verified_failed, af_sverify_told);
2745 if (rc != FAIL || (log_extra_selector & LX_sender_verify_fail) != 0)
2746 log_write(0, LOG_MAIN|LOG_REJECT, "%s sender verify %s for <%s>%s",
2747 host_and_ident(TRUE),
2748 ((sender_verified_failed->special_action & 255) == DEFER)? "defer":"fail",
2749 sender_verified_failed->address,
2750 (sender_verified_failed->message == NULL)? US"" :
2751 string_sprintf(": %s", sender_verified_failed->message));
2753 if (rc == FAIL && sender_verified_failed->user_message != NULL)
2754 smtp_respond(smtp_code, codelen, FALSE, string_sprintf(
2755 testflag(sender_verified_failed, af_verify_pmfail)?
2756 "Postmaster verification failed while checking <%s>\n%s\n"
2757 "Several RFCs state that you are required to have a postmaster\n"
2758 "mailbox for each mail domain. This host does not accept mail\n"
2759 "from domains whose servers reject the postmaster address."
2761 testflag(sender_verified_failed, af_verify_nsfail)?
2762 "Callback setup failed while verifying <%s>\n%s\n"
2763 "The initial connection, or a HELO or MAIL FROM:<> command was\n"
2764 "rejected. Refusing MAIL FROM:<> does not help fight spam, disregards\n"
2765 "RFC requirements, and stops you from receiving standard bounce\n"
2766 "messages. This host does not accept mail from domains whose servers\n"
2769 "Verification failed for <%s>\n%s",
2770 sender_verified_failed->address,
2771 sender_verified_failed->user_message));
2773 rcpt_in_progress = save_rcpt_in_progress;
2776 /* Sort out text for logging */
2778 log_msg = (log_msg == NULL)? US"" : string_sprintf(": %s", log_msg);
2779 lognl = Ustrchr(log_msg, '\n');
2780 if (lognl != NULL) *lognl = 0;
2782 /* Send permanent failure response to the command, but the code used isn't
2783 always a 5xx one - see comments at the start of this function. If the original
2784 rc was FAIL_DROP we drop the connection and yield 2. */
2786 if (rc == FAIL) smtp_respond(smtp_code, codelen, TRUE, (user_msg == NULL)?
2787 US"Administrative prohibition" : user_msg);
2789 /* Send temporary failure response to the command. Don't give any details,
2790 unless acl_temp_details is set. This is TRUE for a callout defer, a "defer"
2791 verb, and for a header verify when smtp_return_error_details is set.
2793 This conditional logic is all somewhat of a mess because of the odd
2794 interactions between temp_details and return_error_details. One day it should
2795 be re-implemented in a tidier fashion. */
2799 if (acl_temp_details && user_msg != NULL)
2801 if (smtp_return_error_details &&
2802 sender_verified_failed != NULL &&
2803 sender_verified_failed->message != NULL)
2805 smtp_respond(smtp_code, codelen, FALSE, sender_verified_failed->message);
2807 smtp_respond(smtp_code, codelen, TRUE, user_msg);
2810 smtp_respond(smtp_code, codelen, TRUE,
2811 US"Temporary local problem - please try later");
2814 /* Log the incident to the logs that are specified by log_reject_target
2815 (default main, reject). This can be empty to suppress logging of rejections. If
2816 the connection is not forcibly to be dropped, return 0. Otherwise, log why it
2817 is closing if required and return 2. */
2819 if (log_reject_target != 0)
2822 uschar * s = s_tlslog(NULL, NULL, NULL);
2827 log_write(0, log_reject_target, "%s%s %s%srejected %s%s",
2828 host_and_ident(TRUE), s,
2829 sender_info, (rc == FAIL)? US"" : US"temporarily ", what, log_msg);
2832 if (!drop) return 0;
2834 log_write(L_smtp_connection, LOG_MAIN, "%s closed by DROP in ACL",
2835 smtp_get_connection_info());
2837 /* Run the not-quit ACL, but without any custom messages. This should not be a
2838 problem, because we get here only if some other ACL has issued "drop", and
2839 in that case, *its* custom messages will have been used above. */
2841 smtp_notquit_exit(US"acl-drop", NULL, NULL);
2848 /*************************************************
2849 * Handle SMTP exit when QUIT is not given *
2850 *************************************************/
2852 /* This function provides a logging/statistics hook for when an SMTP connection
2853 is dropped on the floor or the other end goes away. It's a global function
2854 because it's called from receive.c as well as this module. As well as running
2855 the NOTQUIT ACL, if there is one, this function also outputs a final SMTP
2856 response, either with a custom message from the ACL, or using a default. There
2857 is one case, however, when no message is output - after "drop". In that case,
2858 the ACL that obeyed "drop" has already supplied the custom message, and NULL is
2859 passed to this function.
2861 In case things go wrong while processing this function, causing an error that
2862 may re-enter this funtion, there is a recursion check.
2865 reason What $smtp_notquit_reason will be set to in the ACL;
2866 if NULL, the ACL is not run
2867 code The error code to return as part of the response
2868 defaultrespond The default message if there's no user_msg
2874 smtp_notquit_exit(uschar *reason, uschar *code, uschar *defaultrespond, ...)
2877 uschar *user_msg = NULL;
2878 uschar *log_msg = NULL;
2880 /* Check for recursive acll */
2882 if (smtp_exit_function_called)
2884 log_write(0, LOG_PANIC, "smtp_notquit_exit() called more than once (%s)",
2888 smtp_exit_function_called = TRUE;
2890 /* Call the not-QUIT ACL, if there is one, unless no reason is given. */
2892 if (acl_smtp_notquit != NULL && reason != NULL)
2894 smtp_notquit_reason = reason;
2895 rc = acl_check(ACL_WHERE_NOTQUIT, NULL, acl_smtp_notquit, &user_msg,
2898 log_write(0, LOG_MAIN|LOG_PANIC, "ACL for not-QUIT returned ERROR: %s",
2902 /* Write an SMTP response if we are expected to give one. As the default
2903 responses are all internal, they should always fit in the buffer, but code a
2904 warning, just in case. Note that string_vformat() still leaves a complete
2905 string, even if it is incomplete. */
2907 if (code != NULL && defaultrespond != NULL)
2909 if (user_msg == NULL)
2913 va_start(ap, defaultrespond);
2914 if (!string_vformat(buffer, sizeof(buffer), CS defaultrespond, ap))
2915 log_write(0, LOG_MAIN|LOG_PANIC, "string too large in smtp_notquit_exit()");
2916 smtp_printf("%s %s\r\n", code, buffer);
2920 smtp_respond(code, 3, TRUE, user_msg);
2928 /*************************************************
2929 * Verify HELO argument *
2930 *************************************************/
2932 /* This function is called if helo_verify_hosts or helo_try_verify_hosts is
2933 matched. It is also called from ACL processing if verify = helo is used and
2934 verification was not previously tried (i.e. helo_try_verify_hosts was not
2935 matched). The result of its processing is to set helo_verified and
2936 helo_verify_failed. These variables should both be FALSE for this function to
2939 Note that EHLO/HELO is legitimately allowed to quote an address literal. Allow
2940 for IPv6 ::ffff: literals.
2943 Returns: TRUE if testing was completed;
2944 FALSE on a temporary failure
2948 smtp_verify_helo(void)
2952 HDEBUG(D_receive) debug_printf("verifying EHLO/HELO argument \"%s\"\n",
2955 if (sender_helo_name == NULL)
2957 HDEBUG(D_receive) debug_printf("no EHLO/HELO command was issued\n");
2960 /* Deal with the case of -bs without an IP address */
2962 else if (sender_host_address == NULL)
2964 HDEBUG(D_receive) debug_printf("no client IP address: assume success\n");
2965 helo_verified = TRUE;
2968 /* Deal with the more common case when there is a sending IP address */
2970 else if (sender_helo_name[0] == '[')
2972 helo_verified = Ustrncmp(sender_helo_name+1, sender_host_address,
2973 Ustrlen(sender_host_address)) == 0;
2978 if (strncmpic(sender_host_address, US"::ffff:", 7) == 0)
2979 helo_verified = Ustrncmp(sender_helo_name + 1,
2980 sender_host_address + 7, Ustrlen(sender_host_address) - 7) == 0;
2985 { if (helo_verified) debug_printf("matched host address\n"); }
2988 /* Do a reverse lookup if one hasn't already given a positive or negative
2989 response. If that fails, or the name doesn't match, try checking with a forward
2994 if (sender_host_name == NULL && !host_lookup_failed)
2995 yield = host_name_lookup() != DEFER;
2997 /* If a host name is known, check it and all its aliases. */
2999 if (sender_host_name != NULL)
3001 helo_verified = strcmpic(sender_host_name, sender_helo_name) == 0;
3005 HDEBUG(D_receive) debug_printf("matched host name\n");
3009 uschar **aliases = sender_host_aliases;
3010 while (*aliases != NULL)
3012 helo_verified = strcmpic(*aliases++, sender_helo_name) == 0;
3013 if (helo_verified) break;
3018 debug_printf("matched alias %s\n", *(--aliases));
3023 /* Final attempt: try a forward lookup of the helo name */
3029 h.name = sender_helo_name;
3033 HDEBUG(D_receive) debug_printf("getting IP address for %s\n",
3035 rc = host_find_byname(&h, NULL, 0, NULL, TRUE);
3036 if (rc == HOST_FOUND || rc == HOST_FOUND_LOCAL)
3041 if (Ustrcmp(hh->address, sender_host_address) == 0)
3043 helo_verified = TRUE;
3045 debug_printf("IP address for %s matches calling address\n",
3055 if (!helo_verified) helo_verify_failed = TRUE; /* We've tried ... */
3062 /*************************************************
3063 * Send user response message *
3064 *************************************************/
3066 /* This function is passed a default response code and a user message. It calls
3067 smtp_message_code() to check and possibly modify the response code, and then
3068 calls smtp_respond() to transmit the response. I put this into a function
3069 just to avoid a lot of repetition.
3072 code the response code
3073 user_msg the user message
3079 smtp_user_msg(uschar *code, uschar *user_msg)
3082 smtp_message_code(&code, &len, &user_msg, NULL);
3083 smtp_respond(code, len, TRUE, user_msg);
3088 /*************************************************
3089 * Initialize for SMTP incoming message *
3090 *************************************************/
3092 /* This function conducts the initial dialogue at the start of an incoming SMTP
3093 message, and builds a list of recipients. However, if the incoming message
3094 is part of a batch (-bS option) a separate function is called since it would
3095 be messy having tests splattered about all over this function. This function
3096 therefore handles the case where interaction is occurring. The input and output
3097 files are set up in smtp_in and smtp_out.
3099 The global recipients_list is set to point to a vector of recipient_item
3100 blocks, whose number is given by recipients_count. This is extended by the
3101 receive_add_recipient() function. The global variable sender_address is set to
3102 the sender's address. The yield is +1 if a message has been successfully
3103 started, 0 if a QUIT command was encountered or the connection was refused from
3104 the particular host, or -1 if the connection was lost.
3108 Returns: > 0 message successfully started (reached DATA)
3109 = 0 QUIT read or end of file reached or call refused
3114 smtp_setup_msg(void)
3117 BOOL toomany = FALSE;
3118 BOOL discarded = FALSE;
3119 BOOL last_was_rej_mail = FALSE;
3120 BOOL last_was_rcpt = FALSE;
3121 void *reset_point = store_get(0);
3123 DEBUG(D_receive) debug_printf("smtp_setup_msg entered\n");
3125 /* Reset for start of new message. We allow one RSET not to be counted as a
3126 nonmail command, for those MTAs that insist on sending it between every
3127 message. Ditto for EHLO/HELO and for STARTTLS, to allow for going in and out of
3128 TLS between messages (an Exim client may do this if it has messages queued up
3129 for the host). Note: we do NOT reset AUTH at this point. */
3131 smtp_reset(reset_point);
3132 message_ended = END_NOTSTARTED;
3134 cmd_list[CMD_LIST_RSET].is_mail_cmd = TRUE;
3135 cmd_list[CMD_LIST_HELO].is_mail_cmd = TRUE;
3136 cmd_list[CMD_LIST_EHLO].is_mail_cmd = TRUE;
3138 cmd_list[CMD_LIST_STARTTLS].is_mail_cmd = TRUE;
3141 /* Set the local signal handler for SIGTERM - it tries to end off tidily */
3143 os_non_restarting_signal(SIGTERM, command_sigterm_handler);
3145 /* Batched SMTP is handled in a different function. */
3147 if (smtp_batched_input) return smtp_setup_batch_msg();
3149 /* Deal with SMTP commands. This loop is exited by setting done to a POSITIVE
3150 value. The values are 2 larger than the required yield of the function. */
3154 const uschar **argv;
3155 uschar *etrn_command;
3156 uschar *etrn_serialize_key;
3158 uschar *log_msg, *smtp_code;
3159 uschar *user_msg = NULL;
3160 uschar *recipient = NULL;
3161 uschar *hello = NULL;
3162 const uschar *set_id = NULL;
3164 BOOL was_rej_mail = FALSE;
3165 BOOL was_rcpt = FALSE;
3166 void (*oldsignal)(int);
3168 int start, end, sender_domain, recipient_domain;
3172 uschar *orcpt = NULL;
3175 switch(smtp_read_command(TRUE))
3177 /* The AUTH command is not permitted to occur inside a transaction, and may
3178 occur successfully only once per connection. Actually, that isn't quite
3179 true. When TLS is started, all previous information about a connection must
3180 be discarded, so a new AUTH is permitted at that time.
3182 AUTH may only be used when it has been advertised. However, it seems that
3183 there are clients that send AUTH when it hasn't been advertised, some of
3184 them even doing this after HELO. And there are MTAs that accept this. Sigh.
3185 So there's a get-out that allows this to happen.
3187 AUTH is initially labelled as a "nonmail command" so that one occurrence
3188 doesn't get counted. We change the label here so that multiple failing
3189 AUTHS will eventually hit the nonmail threshold. */
3193 authentication_failed = TRUE;
3194 cmd_list[CMD_LIST_AUTH].is_mail_cmd = FALSE;
3196 if (!auth_advertised && !allow_auth_unadvertised)
3198 done = synprot_error(L_smtp_protocol_error, 503, NULL,
3199 US"AUTH command used when not advertised");
3202 if (sender_host_authenticated != NULL)
3204 done = synprot_error(L_smtp_protocol_error, 503, NULL,
3205 US"already authenticated");
3208 if (sender_address != NULL)
3210 done = synprot_error(L_smtp_protocol_error, 503, NULL,
3211 US"not permitted in mail transaction");
3217 if (acl_smtp_auth != NULL)
3219 rc = acl_check(ACL_WHERE_AUTH, NULL, acl_smtp_auth, &user_msg, &log_msg);
3222 done = smtp_handle_acl_fail(ACL_WHERE_AUTH, rc, user_msg, log_msg);
3227 /* Find the name of the requested authentication mechanism. */
3230 while ((c = *smtp_cmd_data) != 0 && !isspace(c))
3232 if (!isalnum(c) && c != '-' && c != '_')
3234 done = synprot_error(L_smtp_syntax_error, 501, NULL,
3235 US"invalid character in authentication mechanism name");
3241 /* If not at the end of the line, we must be at white space. Terminate the
3242 name and move the pointer on to any data that may be present. */
3244 if (*smtp_cmd_data != 0)
3246 *smtp_cmd_data++ = 0;
3247 while (isspace(*smtp_cmd_data)) smtp_cmd_data++;
3250 /* Search for an authentication mechanism which is configured for use
3251 as a server and which has been advertised (unless, sigh, allow_auth_
3252 unadvertised is set). */
3254 for (au = auths; au != NULL; au = au->next)
3256 if (strcmpic(s, au->public_name) == 0 && au->server &&
3257 (au->advertised || allow_auth_unadvertised)) break;
3262 done = synprot_error(L_smtp_protocol_error, 504, NULL,
3263 string_sprintf("%s authentication mechanism not supported", s));
3267 /* Run the checking code, passing the remainder of the command line as
3268 data. Initials the $auth<n> variables as empty. Initialize $0 empty and set
3269 it as the only set numerical variable. The authenticator may set $auth<n>
3270 and also set other numeric variables. The $auth<n> variables are preferred
3271 nowadays; the numerical variables remain for backwards compatibility.
3273 Afterwards, have a go at expanding the set_id string, even if
3274 authentication failed - for bad passwords it can be useful to log the
3275 userid. On success, require set_id to expand and exist, and put it in
3276 authenticated_id. Save this in permanent store, as the working store gets
3277 reset at HELO, RSET, etc. */
3279 for (i = 0; i < AUTH_VARS; i++) auth_vars[i] = NULL;
3281 expand_nlength[0] = 0; /* $0 contains nothing */
3283 c = (au->info->servercode)(au, smtp_cmd_data);
3284 if (au->set_id != NULL) set_id = expand_string(au->set_id);
3285 expand_nmax = -1; /* Reset numeric variables */
3286 for (i = 0; i < AUTH_VARS; i++) auth_vars[i] = NULL; /* Reset $auth<n> */
3288 /* The value of authenticated_id is stored in the spool file and printed in
3289 log lines. It must not contain binary zeros or newline characters. In
3290 normal use, it never will, but when playing around or testing, this error
3291 can (did) happen. To guard against this, ensure that the id contains only
3292 printing characters. */
3294 if (set_id != NULL) set_id = string_printing(set_id);
3296 /* For the non-OK cases, set up additional logging data if set_id
3301 if (set_id != NULL && *set_id != 0)
3302 set_id = string_sprintf(" (set_id=%s)", set_id);
3306 /* Switch on the result */
3311 if (au->set_id == NULL || set_id != NULL) /* Complete success */
3313 if (set_id != NULL) authenticated_id = string_copy_malloc(set_id);
3314 sender_host_authenticated = au->name;
3315 authentication_failed = FALSE;
3316 authenticated_fail_id = NULL; /* Impossible to already be set? */
3318 protocols[pextend + pauthed + ((tls_in.active >= 0)? pcrpted:0)] +
3319 ((sender_host_address != NULL)? pnlocal : 0);
3320 s = ss = US"235 Authentication succeeded";
3321 authenticated_by = au;
3325 /* Authentication succeeded, but we failed to expand the set_id string.
3326 Treat this as a temporary error. */
3328 auth_defer_msg = expand_string_message;
3332 if (set_id != NULL) authenticated_fail_id = string_copy_malloc(set_id);
3333 s = string_sprintf("435 Unable to authenticate at present%s",
3334 auth_defer_user_msg);
3335 ss = string_sprintf("435 Unable to authenticate at present%s: %s",
3336 set_id, auth_defer_msg);
3340 s = ss = US"501 Invalid base64 data";
3344 s = ss = US"501 Authentication cancelled";
3348 s = ss = US"553 Initial data not expected";
3352 if (set_id != NULL) authenticated_fail_id = string_copy_malloc(set_id);
3353 s = US"535 Incorrect authentication data";
3354 ss = string_sprintf("535 Incorrect authentication data%s", set_id);
3358 if (set_id != NULL) authenticated_fail_id = string_copy_malloc(set_id);
3359 s = US"435 Internal error";
3360 ss = string_sprintf("435 Internal error%s: return %d from authentication "
3361 "check", set_id, c);
3365 smtp_printf("%s\r\n", s);
3367 log_write(0, LOG_MAIN|LOG_REJECT, "%s authenticator failed for %s: %s",
3368 au->name, host_and_ident(FALSE), ss);
3370 break; /* AUTH_CMD */
3372 /* The HELO/EHLO commands are permitted to appear in the middle of a
3373 session as well as at the beginning. They have the effect of a reset in
3374 addition to their other functions. Their absence at the start cannot be
3375 taken to be an error.
3379 If the EHLO command is not acceptable to the SMTP server, 501, 500,
3380 or 502 failure replies MUST be returned as appropriate. The SMTP
3381 server MUST stay in the same state after transmitting these replies
3382 that it was in before the EHLO was received.
3384 Therefore, we do not do the reset until after checking the command for
3385 acceptability. This change was made for Exim release 4.11. Previously
3386 it did the reset first. */
3399 HELO_EHLO: /* Common code for HELO and EHLO */
3400 cmd_list[CMD_LIST_HELO].is_mail_cmd = FALSE;
3401 cmd_list[CMD_LIST_EHLO].is_mail_cmd = FALSE;
3403 /* Reject the HELO if its argument was invalid or non-existent. A
3404 successful check causes the argument to be saved in malloc store. */
3406 if (!check_helo(smtp_cmd_data))
3408 smtp_printf("501 Syntactically invalid %s argument(s)\r\n", hello);
3410 log_write(0, LOG_MAIN|LOG_REJECT, "rejected %s from %s: syntactically "
3411 "invalid argument(s): %s", hello, host_and_ident(FALSE),
3412 (*smtp_cmd_argument == 0)? US"(no argument given)" :
3413 string_printing(smtp_cmd_argument));
3415 if (++synprot_error_count > smtp_max_synprot_errors)
3417 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
3418 "syntax or protocol errors (last command was \"%s\")",
3419 host_and_ident(FALSE), smtp_cmd_buffer);
3426 /* If sender_host_unknown is true, we have got here via the -bs interface,
3427 not called from inetd. Otherwise, we are running an IP connection and the
3428 host address will be set. If the helo name is the primary name of this
3429 host and we haven't done a reverse lookup, force one now. If helo_required
3430 is set, ensure that the HELO name matches the actual host. If helo_verify
3431 is set, do the same check, but softly. */
3433 if (!sender_host_unknown)
3435 BOOL old_helo_verified = helo_verified;
3436 uschar *p = smtp_cmd_data;
3438 while (*p != 0 && !isspace(*p)) { *p = tolower(*p); p++; }
3441 /* Force a reverse lookup if HELO quoted something in helo_lookup_domains
3442 because otherwise the log can be confusing. */
3444 if (sender_host_name == NULL &&
3445 (deliver_domain = sender_helo_name, /* set $domain */
3446 match_isinlist(sender_helo_name, CUSS &helo_lookup_domains, 0,
3447 &domainlist_anchor, NULL, MCL_DOMAIN, TRUE, NULL)) == OK)
3448 (void)host_name_lookup();
3450 /* Rebuild the fullhost info to include the HELO name (and the real name
3451 if it was looked up.) */
3453 host_build_sender_fullhost(); /* Rebuild */
3454 set_process_info("handling%s incoming connection from %s",
3455 (tls_in.active >= 0)? " TLS" : "", host_and_ident(FALSE));
3457 /* Verify if configured. This doesn't give much security, but it does
3458 make some people happy to be able to do it. If helo_required is set,
3459 (host matches helo_verify_hosts) failure forces rejection. If helo_verify
3460 is set (host matches helo_try_verify_hosts), it does not. This is perhaps
3461 now obsolescent, since the verification can now be requested selectively
3464 helo_verified = helo_verify_failed = FALSE;
3465 if (helo_required || helo_verify)
3467 BOOL tempfail = !smtp_verify_helo();
3472 smtp_printf("%d %s argument does not match calling host\r\n",
3473 tempfail? 451 : 550, hello);
3474 log_write(0, LOG_MAIN|LOG_REJECT, "%srejected \"%s %s\" from %s",
3475 tempfail? "temporarily " : "",
3476 hello, sender_helo_name, host_and_ident(FALSE));
3477 helo_verified = old_helo_verified;
3478 break; /* End of HELO/EHLO processing */
3480 HDEBUG(D_all) debug_printf("%s verification failed but host is in "
3481 "helo_try_verify_hosts\n", hello);
3486 #ifdef EXPERIMENTAL_SPF
3487 /* set up SPF context */
3488 spf_init(sender_helo_name, sender_host_address);
3491 /* Apply an ACL check if one is defined; afterwards, recheck
3492 synchronization in case the client started sending in a delay. */
3494 if (acl_smtp_helo != NULL)
3496 rc = acl_check(ACL_WHERE_HELO, NULL, acl_smtp_helo, &user_msg, &log_msg);
3499 done = smtp_handle_acl_fail(ACL_WHERE_HELO, rc, user_msg, log_msg);
3500 sender_helo_name = NULL;
3501 host_build_sender_fullhost(); /* Rebuild */
3504 else if (!check_sync()) goto SYNC_FAILURE;
3507 /* Generate an OK reply. The default string includes the ident if present,
3508 and also the IP address if present. Reflecting back the ident is intended
3509 as a deterrent to mail forgers. For maximum efficiency, and also because
3510 some broken systems expect each response to be in a single packet, arrange
3511 that the entire reply is sent in one write(). */
3513 auth_advertised = FALSE;
3514 pipelining_advertised = FALSE;
3516 tls_advertised = FALSE;
3518 dsn_advertised = FALSE;
3519 #ifdef EXPERIMENTAL_INTERNATIONAL
3520 smtputf8_advertised = FALSE;
3523 smtp_code = US"250 "; /* Default response code plus space*/
3524 if (user_msg == NULL)
3526 s = string_sprintf("%.3s %s Hello %s%s%s",
3528 smtp_active_hostname,
3529 (sender_ident == NULL)? US"" : sender_ident,
3530 (sender_ident == NULL)? US"" : US" at ",
3531 (sender_host_name == NULL)? sender_helo_name : sender_host_name);
3536 if (sender_host_address != NULL)
3538 s = string_cat(s, &size, &ptr, US" [", 2);
3539 s = string_cat(s, &size, &ptr, sender_host_address,
3540 Ustrlen(sender_host_address));
3541 s = string_cat(s, &size, &ptr, US"]", 1);
3545 /* A user-supplied EHLO greeting may not contain more than one line. Note
3546 that the code returned by smtp_message_code() includes the terminating
3547 whitespace character. */
3553 smtp_message_code(&smtp_code, &codelen, &user_msg, NULL);
3554 s = string_sprintf("%.*s%s", codelen, smtp_code, user_msg);
3555 if ((ss = strpbrk(CS s, "\r\n")) != NULL)
3557 log_write(0, LOG_MAIN|LOG_PANIC, "EHLO/HELO response must not contain "
3558 "newlines: message truncated: %s", string_printing(s));
3565 s = string_cat(s, &size, &ptr, US"\r\n", 2);
3567 /* If we received EHLO, we must create a multiline response which includes
3568 the functions supported. */
3574 /* I'm not entirely happy with this, as an MTA is supposed to check
3575 that it has enough room to accept a message of maximum size before
3576 it sends this. However, there seems little point in not sending it.
3577 The actual size check happens later at MAIL FROM time. By postponing it
3578 till then, VRFY and EXPN can be used after EHLO when space is short. */
3580 if (thismessage_size_limit > 0)
3582 sprintf(CS big_buffer, "%.3s-SIZE %d\r\n", smtp_code,
3583 thismessage_size_limit);
3584 s = string_cat(s, &size, &ptr, big_buffer, Ustrlen(big_buffer));
3588 s = string_cat(s, &size, &ptr, smtp_code, 3);
3589 s = string_cat(s, &size, &ptr, US"-SIZE\r\n", 7);
3592 /* Exim does not do protocol conversion or data conversion. It is 8-bit
3593 clean; if it has an 8-bit character in its hand, it just sends it. It
3594 cannot therefore specify 8BITMIME and remain consistent with the RFCs.
3595 However, some users want this option simply in order to stop MUAs
3596 mangling messages that contain top-bit-set characters. It is therefore
3597 provided as an option. */
3599 if (accept_8bitmime)
3601 s = string_cat(s, &size, &ptr, smtp_code, 3);
3602 s = string_cat(s, &size, &ptr, US"-8BITMIME\r\n", 11);
3605 /* Advertise DSN support if configured to do so. */
3606 if (verify_check_host(&dsn_advertise_hosts) != FAIL)
3608 s = string_cat(s, &size, &ptr, smtp_code, 3);
3609 s = string_cat(s, &size, &ptr, US"-DSN\r\n", 6);
3610 dsn_advertised = TRUE;
3613 /* Advertise ETRN if there's an ACL checking whether a host is
3614 permitted to issue it; a check is made when any host actually tries. */
3616 if (acl_smtp_etrn != NULL)
3618 s = string_cat(s, &size, &ptr, smtp_code, 3);
3619 s = string_cat(s, &size, &ptr, US"-ETRN\r\n", 7);
3622 /* Advertise EXPN if there's an ACL checking whether a host is
3623 permitted to issue it; a check is made when any host actually tries. */
3625 if (acl_smtp_expn != NULL)
3627 s = string_cat(s, &size, &ptr, smtp_code, 3);
3628 s = string_cat(s, &size, &ptr, US"-EXPN\r\n", 7);
3631 /* Exim is quite happy with pipelining, so let the other end know that
3632 it is safe to use it, unless advertising is disabled. */
3634 if (pipelining_enable &&
3635 verify_check_host(&pipelining_advertise_hosts) == OK)
3637 s = string_cat(s, &size, &ptr, smtp_code, 3);
3638 s = string_cat(s, &size, &ptr, US"-PIPELINING\r\n", 13);
3639 sync_cmd_limit = NON_SYNC_CMD_PIPELINING;
3640 pipelining_advertised = TRUE;
3644 /* If any server authentication mechanisms are configured, advertise
3645 them if the current host is in auth_advertise_hosts. The problem with
3646 advertising always is that some clients then require users to
3647 authenticate (and aren't configurable otherwise) even though it may not
3648 be necessary (e.g. if the host is in host_accept_relay).
3650 RFC 2222 states that SASL mechanism names contain only upper case
3651 letters, so output the names in upper case, though we actually recognize
3652 them in either case in the AUTH command. */
3656 if (verify_check_host(&auth_advertise_hosts) == OK)
3660 for (au = auths; au != NULL; au = au->next)
3662 if (au->server && (au->advertise_condition == NULL ||
3663 expand_check_condition(au->advertise_condition, au->name,
3664 US"authenticator")))
3669 s = string_cat(s, &size, &ptr, smtp_code, 3);
3670 s = string_cat(s, &size, &ptr, US"-AUTH", 5);
3672 auth_advertised = TRUE;
3675 s = string_cat(s, &size, &ptr, US" ", 1);
3676 s = string_cat(s, &size, &ptr, au->public_name,
3677 Ustrlen(au->public_name));
3678 while (++saveptr < ptr) s[saveptr] = toupper(s[saveptr]);
3679 au->advertised = TRUE;
3681 else au->advertised = FALSE;
3683 if (!first) s = string_cat(s, &size, &ptr, US"\r\n", 2);
3687 /* Advertise TLS (Transport Level Security) aka SSL (Secure Socket Layer)
3688 if it has been included in the binary, and the host matches
3689 tls_advertise_hosts. We must *not* advertise if we are already in a
3690 secure connection. */
3693 if (tls_in.active < 0 &&
3694 verify_check_host(&tls_advertise_hosts) != FAIL)
3696 s = string_cat(s, &size, &ptr, smtp_code, 3);
3697 s = string_cat(s, &size, &ptr, US"-STARTTLS\r\n", 11);
3698 tls_advertised = TRUE;
3702 #ifndef DISABLE_PRDR
3703 /* Per Recipient Data Response, draft by Eric A. Hall extending RFC */
3706 s = string_cat(s, &size, &ptr, smtp_code, 3);
3707 s = string_cat(s, &size, &ptr, US"-PRDR\r\n", 7);
3711 #ifdef EXPERIMENTAL_INTERNATIONAL
3712 if ( accept_8bitmime
3713 && verify_check_host(&smtputf8_advertise_hosts) != FAIL)
3715 s = string_cat(s, &size, &ptr, smtp_code, 3);
3716 s = string_cat(s, &size, &ptr, US"-SMTPUTF8\r\n", 11);
3717 smtputf8_advertised = TRUE;
3721 /* Finish off the multiline reply with one that is always available. */
3723 s = string_cat(s, &size, &ptr, smtp_code, 3);
3724 s = string_cat(s, &size, &ptr, US" HELP\r\n", 7);
3727 /* Terminate the string (for debug), write it, and note that HELO/EHLO
3733 if (tls_in.active >= 0) (void)tls_write(TRUE, s, ptr); else
3737 int i = fwrite(s, 1, ptr, smtp_out); i = i; /* compiler quietening */
3742 while ((cr = Ustrchr(s, '\r')) != NULL) /* lose CRs */
3743 memmove(cr, cr + 1, (ptr--) - (cr - s));
3744 debug_printf("SMTP>> %s", s);
3748 /* Reset the protocol and the state, abandoning any previous message. */
3750 received_protocol = (esmtp?
3752 ((sender_host_authenticated != NULL)? pauthed : 0) +
3753 ((tls_in.active >= 0)? pcrpted : 0)]
3755 protocols[pnormal + ((tls_in.active >= 0)? pcrpted : 0)])
3757 ((sender_host_address != NULL)? pnlocal : 0);
3759 smtp_reset(reset_point);
3761 break; /* HELO/EHLO */
3764 /* The MAIL command requires an address as an operand. All we do
3765 here is to parse it for syntactic correctness. The form "<>" is
3766 a special case which converts into an empty string. The start/end
3767 pointers in the original are not used further for this address, as
3768 it is the canonical extracted address which is all that is kept. */
3772 smtp_mailcmd_count++; /* Count for limit and ratelimit */
3773 was_rej_mail = TRUE; /* Reset if accepted */
3774 env_mail_type_t * mail_args; /* Sanity check & validate args */
3776 if (helo_required && !helo_seen)
3778 smtp_printf("503 HELO or EHLO required\r\n");
3779 log_write(0, LOG_MAIN|LOG_REJECT, "rejected MAIL from %s: no "
3780 "HELO/EHLO given", host_and_ident(FALSE));
3784 if (sender_address != NULL)
3786 done = synprot_error(L_smtp_protocol_error, 503, NULL,
3787 US"sender already given");
3791 if (smtp_cmd_data[0] == 0)
3793 done = synprot_error(L_smtp_protocol_error, 501, NULL,
3794 US"MAIL must have an address operand");
3798 /* Check to see if the limit for messages per connection would be
3799 exceeded by accepting further messages. */
3801 if (smtp_accept_max_per_connection > 0 &&
3802 smtp_mailcmd_count > smtp_accept_max_per_connection)
3804 smtp_printf("421 too many messages in this connection\r\n");
3805 log_write(0, LOG_MAIN|LOG_REJECT, "rejected MAIL command %s: too many "
3806 "messages in one connection", host_and_ident(TRUE));
3810 /* Reset for start of message - even if this is going to fail, we
3811 obviously need to throw away any previous data. */
3813 smtp_reset(reset_point);
3815 sender_data = recipient_data = NULL;
3817 /* Loop, checking for ESMTP additions to the MAIL FROM command. */
3821 uschar *name, *value, *end;
3822 unsigned long int size;
3823 BOOL arg_error = FALSE;
3825 if (!extract_option(&name, &value)) break;
3827 for (mail_args = env_mail_type_list;
3828 (char *)mail_args < (char *)env_mail_type_list + sizeof(env_mail_type_list);
3832 if (strcmpic(name, mail_args->name) == 0)
3835 if (mail_args->need_value && strcmpic(value, US"") == 0)
3838 switch(mail_args->value)
3840 /* Handle SIZE= by reading the value. We don't do the check till later,
3841 in order to be able to log the sender address on failure. */
3842 case ENV_MAIL_OPT_SIZE:
3843 if (((size = Ustrtoul(value, &end, 10)), *end == 0))
3845 if ((size == ULONG_MAX && errno == ERANGE) || size > INT_MAX)
3847 message_size = (int)size;
3853 /* If this session was initiated with EHLO and accept_8bitmime is set,
3854 Exim will have indicated that it supports the BODY=8BITMIME option. In
3855 fact, it does not support this according to the RFCs, in that it does not
3856 take any special action for forwarding messages containing 8-bit
3857 characters. That is why accept_8bitmime is not the default setting, but
3858 some sites want the action that is provided. We recognize both "8BITMIME"
3859 and "7BIT" as body types, but take no action. */
3860 case ENV_MAIL_OPT_BODY:
3861 if (accept_8bitmime) {
3862 if (strcmpic(value, US"8BITMIME") == 0) {
3864 } else if (strcmpic(value, US"7BIT") == 0) {
3868 done = synprot_error(L_smtp_syntax_error, 501, NULL,
3869 US"invalid data for BODY");
3872 DEBUG(D_receive) debug_printf("8BITMIME: %d\n", body_8bitmime);
3878 /* Handle the two DSN options, but only if configured to do so (which
3879 will have caused "DSN" to be given in the EHLO response). The code itself
3880 is included only if configured in at build time. */
3882 case ENV_MAIL_OPT_RET:
3883 if (dsn_advertised) {
3884 /* Check if RET has already been set */
3886 synprot_error(L_smtp_syntax_error, 501, NULL,
3887 US"RET can be specified once only");
3890 dsn_ret = (strcmpic(value, US"HDRS") == 0)? dsn_ret_hdrs :
3891 (strcmpic(value, US"FULL") == 0)? dsn_ret_full : 0;
3892 DEBUG(D_receive) debug_printf("DSN_RET: %d\n", dsn_ret);
3893 /* Check for invalid invalid value, and exit with error */
3895 synprot_error(L_smtp_syntax_error, 501, NULL,
3896 US"Value for RET is invalid");
3901 case ENV_MAIL_OPT_ENVID:
3902 if (dsn_advertised) {
3903 /* Check if the dsn envid has been already set */
3904 if (dsn_envid != NULL) {
3905 synprot_error(L_smtp_syntax_error, 501, NULL,
3906 US"ENVID can be specified once only");
3909 dsn_envid = string_copy(value);
3910 DEBUG(D_receive) debug_printf("DSN_ENVID: %s\n", dsn_envid);
3914 /* Handle the AUTH extension. If the value given is not "<>" and either
3915 the ACL says "yes" or there is no ACL but the sending host is
3916 authenticated, we set it up as the authenticated sender. However, if the
3917 authenticator set a condition to be tested, we ignore AUTH on MAIL unless
3918 the condition is met. The value of AUTH is an xtext, which means that +,
3919 = and cntrl chars are coded in hex; however "<>" is unaffected by this
3921 case ENV_MAIL_OPT_AUTH:
3922 if (Ustrcmp(value, "<>") != 0)
3927 if (auth_xtextdecode(value, &authenticated_sender) < 0)
3929 /* Put back terminator overrides for error message */
3932 done = synprot_error(L_smtp_syntax_error, 501, NULL,
3933 US"invalid data for AUTH");
3936 if (acl_smtp_mailauth == NULL)
3938 ignore_msg = US"client not authenticated";
3939 rc = (sender_host_authenticated != NULL)? OK : FAIL;
3943 ignore_msg = US"rejected by ACL";
3944 rc = acl_check(ACL_WHERE_MAILAUTH, NULL, acl_smtp_mailauth,
3945 &user_msg, &log_msg);
3951 if (authenticated_by == NULL ||
3952 authenticated_by->mail_auth_condition == NULL ||
3953 expand_check_condition(authenticated_by->mail_auth_condition,
3954 authenticated_by->name, US"authenticator"))
3955 break; /* Accept the AUTH */
3957 ignore_msg = US"server_mail_auth_condition failed";
3958 if (authenticated_id != NULL)
3959 ignore_msg = string_sprintf("%s: authenticated ID=\"%s\"",
3960 ignore_msg, authenticated_id);
3965 authenticated_sender = NULL;
3966 log_write(0, LOG_MAIN, "ignoring AUTH=%s from %s (%s)",
3967 value, host_and_ident(TRUE), ignore_msg);
3970 /* Should only get DEFER or ERROR here. Put back terminator
3971 overrides for error message */
3976 (void)smtp_handle_acl_fail(ACL_WHERE_MAILAUTH, rc, user_msg,
3983 #ifndef DISABLE_PRDR
3984 case ENV_MAIL_OPT_PRDR:
3986 prdr_requested = TRUE;
3990 #ifdef EXPERIMENTAL_INTERNATIONAL
3991 case ENV_MAIL_OPT_UTF8:
3992 if (smtputf8_advertised)
3993 message_smtputf8 = TRUE;
3996 /* Unknown option. Stick back the terminator characters and break
3997 the loop. Do the name-terminator second as extract_option sets
3998 value==name when it found no equal-sign.
3999 An error for a malformed address will occur. */
4006 /* Break out of for loop if switch() had bad argument or
4007 when start of the email address is reached */
4008 if (arg_error) break;
4011 /* If we have passed the threshold for rate limiting, apply the current
4012 delay, and update it for next time, provided this is a limited host. */
4014 if (smtp_mailcmd_count > smtp_rlm_threshold &&
4015 verify_check_host(&smtp_ratelimit_hosts) == OK)
4017 DEBUG(D_receive) debug_printf("rate limit MAIL: delay %.3g sec\n",
4018 smtp_delay_mail/1000.0);
4019 millisleep((int)smtp_delay_mail);
4020 smtp_delay_mail *= smtp_rlm_factor;
4021 if (smtp_delay_mail > (double)smtp_rlm_limit)
4022 smtp_delay_mail = (double)smtp_rlm_limit;
4025 /* Now extract the address, first applying any SMTP-time rewriting. The
4026 TRUE flag allows "<>" as a sender address. */
4028 raw_sender = ((rewrite_existflags & rewrite_smtp) != 0)?
4029 rewrite_one(smtp_cmd_data, rewrite_smtp, NULL, FALSE, US"",
4030 global_rewrite_rules) : smtp_cmd_data;
4032 /* rfc821_domains = TRUE; << no longer needed */
4034 parse_extract_address(raw_sender, &errmess, &start, &end, &sender_domain,
4036 /* rfc821_domains = FALSE; << no longer needed */
4038 if (raw_sender == NULL)
4040 done = synprot_error(L_smtp_syntax_error, 501, smtp_cmd_data, errmess);
4044 sender_address = raw_sender;
4046 /* If there is a configured size limit for mail, check that this message
4047 doesn't exceed it. The check is postponed to this point so that the sender
4050 if (thismessage_size_limit > 0 && message_size > thismessage_size_limit)
4052 smtp_printf("552 Message size exceeds maximum permitted\r\n");
4053 log_write(L_size_reject,
4054 LOG_MAIN|LOG_REJECT, "rejected MAIL FROM:<%s> %s: "
4055 "message too big: size%s=%d max=%d",
4057 host_and_ident(TRUE),
4058 (message_size == INT_MAX)? ">" : "",
4060 thismessage_size_limit);
4061 sender_address = NULL;
4065 /* Check there is enough space on the disk unless configured not to.
4066 When smtp_check_spool_space is set, the check is for thismessage_size_limit
4067 plus the current message - i.e. we accept the message only if it won't
4068 reduce the space below the threshold. Add 5000 to the size to allow for
4069 overheads such as the Received: line and storing of recipients, etc.
4070 By putting the check here, even when SIZE is not given, it allow VRFY
4071 and EXPN etc. to be used when space is short. */
4073 if (!receive_check_fs(
4074 (smtp_check_spool_space && message_size >= 0)?
4075 message_size + 5000 : 0))
4077 smtp_printf("452 Space shortage, please try later\r\n");
4078 sender_address = NULL;
4082 /* If sender_address is unqualified, reject it, unless this is a locally
4083 generated message, or the sending host or net is permitted to send
4084 unqualified addresses - typically local machines behaving as MUAs -
4085 in which case just qualify the address. The flag is set above at the start
4086 of the SMTP connection. */
4088 if (sender_domain == 0 && sender_address[0] != 0)
4090 if (allow_unqualified_sender)
4092 sender_domain = Ustrlen(sender_address) + 1;
4093 sender_address = rewrite_address_qualify(sender_address, FALSE);
4094 DEBUG(D_receive) debug_printf("unqualified address %s accepted\n",
4099 smtp_printf("501 %s: sender address must contain a domain\r\n",
4101 log_write(L_smtp_syntax_error,
4102 LOG_MAIN|LOG_REJECT,
4103 "unqualified sender rejected: <%s> %s%s",
4105 host_and_ident(TRUE),
4107 sender_address = NULL;
4112 /* Apply an ACL check if one is defined, before responding. Afterwards,
4113 when pipelining is not advertised, do another sync check in case the ACL
4114 delayed and the client started sending in the meantime. */
4118 rc = acl_check(ACL_WHERE_MAIL, NULL, acl_smtp_mail, &user_msg, &log_msg);
4119 if (rc == OK && !pipelining_advertised && !check_sync())
4125 if (rc == OK || rc == DISCARD)
4128 smtp_printf("%s%s%s", US"250 OK",
4129 #ifndef DISABLE_PRDR
4130 prdr_requested ? US", PRDR Requested" : US"",
4137 #ifndef DISABLE_PRDR
4139 user_msg = string_sprintf("%s%s", user_msg, US", PRDR Requested");
4141 smtp_user_msg(US"250", user_msg);
4143 smtp_delay_rcpt = smtp_rlr_base;
4144 recipients_discarded = (rc == DISCARD);
4145 was_rej_mail = FALSE;
4149 done = smtp_handle_acl_fail(ACL_WHERE_MAIL, rc, user_msg, log_msg);
4150 sender_address = NULL;
4155 /* The RCPT command requires an address as an operand. There may be any
4156 number of RCPT commands, specifying multiple recipients. We build them all
4157 into a data structure. The start/end values given by parse_extract_address
4158 are not used, as we keep only the extracted address. */
4163 was_rcpt = rcpt_in_progress = TRUE;
4165 /* There must be a sender address; if the sender was rejected and
4166 pipelining was advertised, we assume the client was pipelining, and do not
4167 count this as a protocol error. Reset was_rej_mail so that further RCPTs
4168 get the same treatment. */
4170 if (sender_address == NULL)
4172 if (pipelining_advertised && last_was_rej_mail)
4174 smtp_printf("503 sender not yet given\r\n");
4175 was_rej_mail = TRUE;
4179 done = synprot_error(L_smtp_protocol_error, 503, NULL,
4180 US"sender not yet given");
4181 was_rcpt = FALSE; /* Not a valid RCPT */
4187 /* Check for an operand */
4189 if (smtp_cmd_data[0] == 0)
4191 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4192 US"RCPT must have an address operand");
4197 /* Set the DSN flags orcpt and dsn_flags from the session*/
4203 uschar *name, *value;
4205 if (!extract_option(&name, &value))
4208 if (dsn_advertised && strcmpic(name, US"ORCPT") == 0)
4210 /* Check whether orcpt has been already set */
4213 synprot_error(L_smtp_syntax_error, 501, NULL,
4214 US"ORCPT can be specified once only");
4217 orcpt = string_copy(value);
4218 DEBUG(D_receive) debug_printf("DSN orcpt: %s\n", orcpt);
4221 else if (dsn_advertised && strcmpic(name, US"NOTIFY") == 0)
4223 /* Check if the notify flags have been already set */
4226 synprot_error(L_smtp_syntax_error, 501, NULL,
4227 US"NOTIFY can be specified once only");
4230 if (strcmpic(value, US"NEVER") == 0)
4231 flags |= rf_notify_never;
4238 while (*pp != 0 && *pp != ',') pp++;
4239 if (*pp == ',') *pp++ = 0;
4240 if (strcmpic(p, US"SUCCESS") == 0)
4242 DEBUG(D_receive) debug_printf("DSN: Setting notify success\n");
4243 flags |= rf_notify_success;
4245 else if (strcmpic(p, US"FAILURE") == 0)
4247 DEBUG(D_receive) debug_printf("DSN: Setting notify failure\n");
4248 flags |= rf_notify_failure;
4250 else if (strcmpic(p, US"DELAY") == 0)
4252 DEBUG(D_receive) debug_printf("DSN: Setting notify delay\n");
4253 flags |= rf_notify_delay;
4257 /* Catch any strange values */
4258 synprot_error(L_smtp_syntax_error, 501, NULL,
4259 US"Invalid value for NOTIFY parameter");
4264 DEBUG(D_receive) debug_printf("DSN Flags: %x\n", flags);
4268 /* Unknown option. Stick back the terminator characters and break
4269 the loop. An error for a malformed address will occur. */
4273 DEBUG(D_receive) debug_printf("Invalid RCPT option: %s : %s\n", name, value);
4280 /* Apply SMTP rewriting then extract the working address. Don't allow "<>"
4281 as a recipient address */
4283 recipient = ((rewrite_existflags & rewrite_smtp) != 0)?
4284 rewrite_one(smtp_cmd_data, rewrite_smtp, NULL, FALSE, US"",
4285 global_rewrite_rules) : smtp_cmd_data;
4287 /* rfc821_domains = TRUE; << no longer needed */
4288 recipient = parse_extract_address(recipient, &errmess, &start, &end,
4289 &recipient_domain, FALSE);
4290 /* rfc821_domains = FALSE; << no longer needed */
4292 if (recipient == NULL)
4294 done = synprot_error(L_smtp_syntax_error, 501, smtp_cmd_data, errmess);
4299 /* If the recipient address is unqualified, reject it, unless this is a
4300 locally generated message. However, unqualified addresses are permitted
4301 from a configured list of hosts and nets - typically when behaving as
4302 MUAs rather than MTAs. Sad that SMTP is used for both types of traffic,
4303 really. The flag is set at the start of the SMTP connection.
4305 RFC 1123 talks about supporting "the reserved mailbox postmaster"; I always
4306 assumed this meant "reserved local part", but the revision of RFC 821 and
4307 friends now makes it absolutely clear that it means *mailbox*. Consequently
4308 we must always qualify this address, regardless. */
4310 if (recipient_domain == 0)
4312 if (allow_unqualified_recipient ||
4313 strcmpic(recipient, US"postmaster") == 0)
4315 DEBUG(D_receive) debug_printf("unqualified address %s accepted\n",
4317 recipient_domain = Ustrlen(recipient) + 1;
4318 recipient = rewrite_address_qualify(recipient, TRUE);
4323 smtp_printf("501 %s: recipient address must contain a domain\r\n",
4325 log_write(L_smtp_syntax_error,
4326 LOG_MAIN|LOG_REJECT, "unqualified recipient rejected: "
4327 "<%s> %s%s", recipient, host_and_ident(TRUE),
4333 /* Check maximum allowed */
4335 if (rcpt_count > recipients_max && recipients_max > 0)
4337 if (recipients_max_reject)
4340 smtp_printf("552 too many recipients\r\n");
4342 log_write(0, LOG_MAIN|LOG_REJECT, "too many recipients: message "
4343 "rejected: sender=<%s> %s", sender_address, host_and_ident(TRUE));
4348 smtp_printf("452 too many recipients\r\n");
4350 log_write(0, LOG_MAIN|LOG_REJECT, "too many recipients: excess "
4351 "temporarily rejected: sender=<%s> %s", sender_address,
4352 host_and_ident(TRUE));
4359 /* If we have passed the threshold for rate limiting, apply the current
4360 delay, and update it for next time, provided this is a limited host. */
4362 if (rcpt_count > smtp_rlr_threshold &&
4363 verify_check_host(&smtp_ratelimit_hosts) == OK)
4365 DEBUG(D_receive) debug_printf("rate limit RCPT: delay %.3g sec\n",
4366 smtp_delay_rcpt/1000.0);
4367 millisleep((int)smtp_delay_rcpt);
4368 smtp_delay_rcpt *= smtp_rlr_factor;
4369 if (smtp_delay_rcpt > (double)smtp_rlr_limit)
4370 smtp_delay_rcpt = (double)smtp_rlr_limit;
4373 /* If the MAIL ACL discarded all the recipients, we bypass ACL checking
4374 for them. Otherwise, check the access control list for this recipient. As
4375 there may be a delay in this, re-check for a synchronization error
4376 afterwards, unless pipelining was advertised. */
4378 if (recipients_discarded) rc = DISCARD; else
4380 rc = acl_check(ACL_WHERE_RCPT, recipient, acl_smtp_rcpt, &user_msg,
4382 if (rc == OK && !pipelining_advertised && !check_sync())
4386 /* The ACL was happy */
4390 if (user_msg == NULL) smtp_printf("250 Accepted\r\n");
4391 else smtp_user_msg(US"250", user_msg);
4392 receive_add_recipient(recipient, -1);
4394 /* Set the dsn flags in the recipients_list */
4396 recipients_list[recipients_count-1].orcpt = orcpt;
4398 recipients_list[recipients_count-1].orcpt = NULL;
4401 recipients_list[recipients_count-1].dsn_flags = flags;
4403 recipients_list[recipients_count-1].dsn_flags = 0;
4404 DEBUG(D_receive) debug_printf("DSN: orcpt: %s flags: %d\n", recipients_list[recipients_count-1].orcpt, recipients_list[recipients_count-1].dsn_flags);
4407 /* The recipient was discarded */
4409 else if (rc == DISCARD)
4411 if (user_msg == NULL) smtp_printf("250 Accepted\r\n");
4412 else smtp_user_msg(US"250", user_msg);
4415 log_write(0, LOG_MAIN|LOG_REJECT, "%s F=<%s> rejected RCPT %s: "
4416 "discarded by %s ACL%s%s", host_and_ident(TRUE),
4417 (sender_address_unrewritten != NULL)?
4418 sender_address_unrewritten : sender_address,
4419 smtp_cmd_argument, recipients_discarded? "MAIL" : "RCPT",
4420 (log_msg == NULL)? US"" : US": ",
4421 (log_msg == NULL)? US"" : log_msg);
4424 /* Either the ACL failed the address, or it was deferred. */
4428 if (rc == FAIL) rcpt_fail_count++; else rcpt_defer_count++;
4429 done = smtp_handle_acl_fail(ACL_WHERE_RCPT, rc, user_msg, log_msg);
4434 /* The DATA command is legal only if it follows successful MAIL FROM
4435 and RCPT TO commands. However, if pipelining is advertised, a bad DATA is
4436 not counted as a protocol error if it follows RCPT (which must have been
4437 rejected if there are no recipients.) This function is complete when a
4438 valid DATA command is encountered.
4440 Note concerning the code used: RFC 2821 says this:
4442 - If there was no MAIL, or no RCPT, command, or all such commands
4443 were rejected, the server MAY return a "command out of sequence"
4444 (503) or "no valid recipients" (554) reply in response to the
4447 The example in the pipelining RFC 2920 uses 554, but I use 503 here
4448 because it is the same whether pipelining is in use or not.
4450 If all the RCPT commands that precede DATA provoked the same error message
4451 (often indicating some kind of system error), it is helpful to include it
4452 with the DATA rejection (an idea suggested by Tony Finch). */
4456 if (!discarded && recipients_count <= 0)
4458 if (rcpt_smtp_response_same && rcpt_smtp_response != NULL)
4460 uschar *code = US"503";
4461 int len = Ustrlen(rcpt_smtp_response);
4462 smtp_respond(code, 3, FALSE, US"All RCPT commands were rejected with "
4464 /* Responses from smtp_printf() will have \r\n on the end */
4465 if (len > 2 && rcpt_smtp_response[len-2] == '\r')
4466 rcpt_smtp_response[len-2] = 0;
4467 smtp_respond(code, 3, FALSE, rcpt_smtp_response);
4469 if (pipelining_advertised && last_was_rcpt)
4470 smtp_printf("503 Valid RCPT command must precede DATA\r\n");
4472 done = synprot_error(L_smtp_protocol_error, 503, NULL,
4473 US"valid RCPT command must precede DATA");
4477 if (toomany && recipients_max_reject)
4479 sender_address = NULL; /* This will allow a new MAIL without RSET */
4480 sender_address_unrewritten = NULL;
4481 smtp_printf("554 Too many recipients\r\n");
4485 /* If there is an ACL, re-check the synchronization afterwards, since the
4486 ACL may have delayed. To handle cutthrough delivery enforce a dummy call
4487 to get the DATA command sent. */
4489 if (acl_smtp_predata == NULL && cutthrough.fd < 0) rc = OK; else
4491 uschar * acl= acl_smtp_predata ? acl_smtp_predata : US"accept";
4492 enable_dollar_recipients = TRUE;
4493 rc = acl_check(ACL_WHERE_PREDATA, NULL, acl, &user_msg,
4495 enable_dollar_recipients = FALSE;
4496 if (rc == OK && !check_sync()) goto SYNC_FAILURE;
4503 if (user_msg == NULL)
4504 smtp_printf("%s Enter message, ending with \".\" on a line by itself\r\n", code);
4505 else smtp_user_msg(code, user_msg);
4507 message_ended = END_NOTENDED; /* Indicate in middle of data */
4510 /* Either the ACL failed the address, or it was deferred. */
4513 done = smtp_handle_acl_fail(ACL_WHERE_PREDATA, rc, user_msg, log_msg);
4519 rc = acl_check(ACL_WHERE_VRFY, NULL, acl_smtp_vrfy, &user_msg, &log_msg);
4521 done = smtp_handle_acl_fail(ACL_WHERE_VRFY, rc, user_msg, log_msg);
4527 /* rfc821_domains = TRUE; << no longer needed */
4528 address = parse_extract_address(smtp_cmd_data, &errmess, &start, &end,
4529 &recipient_domain, FALSE);
4530 /* rfc821_domains = FALSE; << no longer needed */
4532 if (address == NULL)
4533 s = string_sprintf("501 %s", errmess);
4536 address_item *addr = deliver_make_addr(address, FALSE);
4537 switch(verify_address(addr, NULL, vopt_is_recipient | vopt_qualify, -1,
4538 -1, -1, NULL, NULL, NULL))
4541 s = string_sprintf("250 <%s> is deliverable", address);
4545 s = (addr->user_message != NULL)?
4546 string_sprintf("451 <%s> %s", address, addr->user_message) :
4547 string_sprintf("451 Cannot resolve <%s> at this time", address);
4551 s = (addr->user_message != NULL)?
4552 string_sprintf("550 <%s> %s", address, addr->user_message) :
4553 string_sprintf("550 <%s> is not deliverable", address);
4554 log_write(0, LOG_MAIN, "VRFY failed for %s %s",
4555 smtp_cmd_argument, host_and_ident(TRUE));
4560 smtp_printf("%s\r\n", s);
4567 rc = acl_check(ACL_WHERE_EXPN, NULL, acl_smtp_expn, &user_msg, &log_msg);
4569 done = smtp_handle_acl_fail(ACL_WHERE_EXPN, rc, user_msg, log_msg);
4572 BOOL save_log_testing_mode = log_testing_mode;
4573 address_test_mode = log_testing_mode = TRUE;
4574 (void) verify_address(deliver_make_addr(smtp_cmd_data, FALSE),
4575 smtp_out, vopt_is_recipient | vopt_qualify | vopt_expn, -1, -1, -1,
4577 address_test_mode = FALSE;
4578 log_testing_mode = save_log_testing_mode; /* true for -bh */
4587 if (!tls_advertised)
4589 done = synprot_error(L_smtp_protocol_error, 503, NULL,
4590 US"STARTTLS command used when not advertised");
4594 /* Apply an ACL check if one is defined */
4596 if (acl_smtp_starttls != NULL)
4598 rc = acl_check(ACL_WHERE_STARTTLS, NULL, acl_smtp_starttls, &user_msg,
4602 done = smtp_handle_acl_fail(ACL_WHERE_STARTTLS, rc, user_msg, log_msg);
4607 /* RFC 2487 is not clear on when this command may be sent, though it
4608 does state that all information previously obtained from the client
4609 must be discarded if a TLS session is started. It seems reasonble to
4610 do an implied RSET when STARTTLS is received. */
4612 incomplete_transaction_log(US"STARTTLS");
4613 smtp_reset(reset_point);
4615 cmd_list[CMD_LIST_STARTTLS].is_mail_cmd = FALSE;
4617 /* There's an attack where more data is read in past the STARTTLS command
4618 before TLS is negotiated, then assumed to be part of the secure session
4619 when used afterwards; we use segregated input buffers, so are not
4620 vulnerable, but we want to note when it happens and, for sheer paranoia,
4621 ensure that the buffer is "wiped".
4622 Pipelining sync checks will normally have protected us too, unless disabled
4623 by configuration. */
4625 if (receive_smtp_buffered())
4628 debug_printf("Non-empty input buffer after STARTTLS; naive attack?");
4629 if (tls_in.active < 0)
4630 smtp_inend = smtp_inptr = smtp_inbuffer;
4631 /* and if TLS is already active, tls_server_start() should fail */
4634 /* There is nothing we value in the input buffer and if TLS is succesfully
4635 negotiated, we won't use this buffer again; if TLS fails, we'll just read
4636 fresh content into it. The buffer contains arbitrary content from an
4637 untrusted remote source; eg: NOOP <shellcode>\r\nSTARTTLS\r\n
4638 It seems safest to just wipe away the content rather than leave it as a
4639 target to jump to. */
4641 memset(smtp_inbuffer, 0, in_buffer_size);
4643 /* Attempt to start up a TLS session, and if successful, discard all
4644 knowledge that was obtained previously. At least, that's what the RFC says,
4645 and that's what happens by default. However, in order to work round YAEB,
4646 there is an option to remember the esmtp state. Sigh.
4648 We must allow for an extra EHLO command and an extra AUTH command after
4649 STARTTLS that don't add to the nonmail command count. */
4651 if ((rc = tls_server_start(tls_require_ciphers)) == OK)
4653 if (!tls_remember_esmtp)
4654 helo_seen = esmtp = auth_advertised = pipelining_advertised = FALSE;
4655 cmd_list[CMD_LIST_EHLO].is_mail_cmd = TRUE;
4656 cmd_list[CMD_LIST_AUTH].is_mail_cmd = TRUE;
4657 if (sender_helo_name != NULL)
4659 store_free(sender_helo_name);
4660 sender_helo_name = NULL;
4661 host_build_sender_fullhost(); /* Rebuild */
4662 set_process_info("handling incoming TLS connection from %s",
4663 host_and_ident(FALSE));
4665 received_protocol = (esmtp?
4666 protocols[pextend + pcrpted +
4667 ((sender_host_authenticated != NULL)? pauthed : 0)]
4669 protocols[pnormal + pcrpted])
4671 ((sender_host_address != NULL)? pnlocal : 0);
4673 sender_host_authenticated = NULL;
4674 authenticated_id = NULL;
4675 sync_cmd_limit = NON_SYNC_CMD_NON_PIPELINING;
4676 DEBUG(D_tls) debug_printf("TLS active\n");
4677 break; /* Successful STARTTLS */
4680 /* Some local configuration problem was discovered before actually trying
4681 to do a TLS handshake; give a temporary error. */
4683 else if (rc == DEFER)
4685 smtp_printf("454 TLS currently unavailable\r\n");
4689 /* Hard failure. Reject everything except QUIT or closed connection. One
4690 cause for failure is a nested STARTTLS, in which case tls_in.active remains
4691 set, but we must still reject all incoming commands. */
4693 DEBUG(D_tls) debug_printf("TLS failed to start\n");
4696 switch(smtp_read_command(FALSE))
4699 log_write(L_smtp_connection, LOG_MAIN, "%s closed by EOF",
4700 smtp_get_connection_info());
4701 smtp_notquit_exit(US"tls-failed", NULL, NULL);
4705 /* It is perhaps arguable as to which exit ACL should be called here,
4706 but as it is probably a situation that almost never arises, it
4707 probably doesn't matter. We choose to call the real QUIT ACL, which in
4708 some sense is perhaps "right". */
4712 if (acl_smtp_quit != NULL)
4714 rc = acl_check(ACL_WHERE_QUIT, NULL, acl_smtp_quit, &user_msg,
4717 log_write(0, LOG_MAIN|LOG_PANIC, "ACL for QUIT returned ERROR: %s",
4720 if (user_msg == NULL)
4721 smtp_printf("221 %s closing connection\r\n", smtp_active_hostname);
4723 smtp_respond(US"221", 3, TRUE, user_msg);
4724 log_write(L_smtp_connection, LOG_MAIN, "%s closed by QUIT",
4725 smtp_get_connection_info());
4730 smtp_printf("554 Security failure\r\n");
4734 tls_close(TRUE, TRUE);
4739 /* The ACL for QUIT is provided for gathering statistical information or
4740 similar; it does not affect the response code, but it can supply a custom
4745 incomplete_transaction_log(US"QUIT");
4746 if (acl_smtp_quit != NULL)
4748 rc = acl_check(ACL_WHERE_QUIT, NULL, acl_smtp_quit, &user_msg, &log_msg);
4750 log_write(0, LOG_MAIN|LOG_PANIC, "ACL for QUIT returned ERROR: %s",
4753 if (user_msg == NULL)
4754 smtp_printf("221 %s closing connection\r\n", smtp_active_hostname);
4756 smtp_respond(US"221", 3, TRUE, user_msg);
4759 tls_close(TRUE, TRUE);
4763 log_write(L_smtp_connection, LOG_MAIN, "%s closed by QUIT",
4764 smtp_get_connection_info());
4770 incomplete_transaction_log(US"RSET");
4771 smtp_reset(reset_point);
4773 smtp_printf("250 Reset OK\r\n");
4774 cmd_list[CMD_LIST_RSET].is_mail_cmd = FALSE;
4780 smtp_printf("250 OK\r\n");
4784 /* Show ETRN/EXPN/VRFY if there's an ACL for checking hosts; if actually
4785 used, a check will be done for permitted hosts. Show STARTTLS only if not
4786 already in a TLS session and if it would be advertised in the EHLO
4791 smtp_printf("214-Commands supported:\r\n");
4795 Ustrcat(buffer, " AUTH");
4797 if (tls_in.active < 0 &&
4798 verify_check_host(&tls_advertise_hosts) != FAIL)
4799 Ustrcat(buffer, " STARTTLS");
4801 Ustrcat(buffer, " HELO EHLO MAIL RCPT DATA");
4802 Ustrcat(buffer, " NOOP QUIT RSET HELP");
4803 if (acl_smtp_etrn != NULL) Ustrcat(buffer, " ETRN");
4804 if (acl_smtp_expn != NULL) Ustrcat(buffer, " EXPN");
4805 if (acl_smtp_vrfy != NULL) Ustrcat(buffer, " VRFY");
4806 smtp_printf("214%s\r\n", buffer);
4812 incomplete_transaction_log(US"connection lost");
4813 smtp_notquit_exit(US"connection-lost", US"421",
4814 US"%s lost input connection", smtp_active_hostname);
4816 /* Don't log by default unless in the middle of a message, as some mailers
4817 just drop the call rather than sending QUIT, and it clutters up the logs.
4820 if (sender_address != NULL || recipients_count > 0)
4821 log_write(L_lost_incoming_connection,
4823 "unexpected %s while reading SMTP command from %s%s",
4824 sender_host_unknown? "EOF" : "disconnection",
4825 host_and_ident(FALSE), smtp_read_error);
4827 else log_write(L_smtp_connection, LOG_MAIN, "%s lost%s",
4828 smtp_get_connection_info(), smtp_read_error);
4836 if (sender_address != NULL)
4838 done = synprot_error(L_smtp_protocol_error, 503, NULL,
4839 US"ETRN is not permitted inside a transaction");
4843 log_write(L_etrn, LOG_MAIN, "ETRN %s received from %s", smtp_cmd_argument,
4844 host_and_ident(FALSE));
4846 rc = acl_check(ACL_WHERE_ETRN, NULL, acl_smtp_etrn, &user_msg, &log_msg);
4849 done = smtp_handle_acl_fail(ACL_WHERE_ETRN, rc, user_msg, log_msg);
4853 /* Compute the serialization key for this command. */
4855 etrn_serialize_key = string_sprintf("etrn-%s\n", smtp_cmd_data);
4857 /* If a command has been specified for running as a result of ETRN, we
4858 permit any argument to ETRN. If not, only the # standard form is permitted,
4859 since that is strictly the only kind of ETRN that can be implemented
4860 according to the RFC. */
4862 if (smtp_etrn_command != NULL)
4866 etrn_command = smtp_etrn_command;
4867 deliver_domain = smtp_cmd_data;
4868 rc = transport_set_up_command(&argv, smtp_etrn_command, TRUE, 0, NULL,
4869 US"ETRN processing", &error);
4870 deliver_domain = NULL;
4873 log_write(0, LOG_MAIN|LOG_PANIC, "failed to set up ETRN command: %s",
4875 smtp_printf("458 Internal failure\r\n");
4880 /* Else set up to call Exim with the -R option. */
4884 if (*smtp_cmd_data++ != '#')
4886 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4887 US"argument must begin with #");
4890 etrn_command = US"exim -R";
4891 argv = CUSS child_exec_exim(CEE_RETURN_ARGV, TRUE, NULL, TRUE, 2, US"-R",
4895 /* If we are host-testing, don't actually do anything. */
4901 debug_printf("ETRN command is: %s\n", etrn_command);
4902 debug_printf("ETRN command execution skipped\n");
4904 if (user_msg == NULL) smtp_printf("250 OK\r\n");
4905 else smtp_user_msg(US"250", user_msg);
4910 /* If ETRN queue runs are to be serialized, check the database to
4911 ensure one isn't already running. */
4913 if (smtp_etrn_serialize && !enq_start(etrn_serialize_key))
4915 smtp_printf("458 Already processing %s\r\n", smtp_cmd_data);
4919 /* Fork a child process and run the command. We don't want to have to
4920 wait for the process at any point, so set SIGCHLD to SIG_IGN before
4921 forking. It should be set that way anyway for external incoming SMTP,
4922 but we save and restore to be tidy. If serialization is required, we
4923 actually run the command in yet another process, so we can wait for it
4924 to complete and then remove the serialization lock. */
4926 oldsignal = signal(SIGCHLD, SIG_IGN);
4928 if ((pid = fork()) == 0)
4930 smtp_input = FALSE; /* This process is not associated with the */
4931 (void)fclose(smtp_in); /* SMTP call any more. */
4932 (void)fclose(smtp_out);
4934 signal(SIGCHLD, SIG_DFL); /* Want to catch child */
4936 /* If not serializing, do the exec right away. Otherwise, fork down
4937 into another process. */
4939 if (!smtp_etrn_serialize || (pid = fork()) == 0)
4941 DEBUG(D_exec) debug_print_argv(argv);
4942 exim_nullstd(); /* Ensure std{in,out,err} exist */
4943 execv(CS argv[0], (char *const *)argv);
4944 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "exec of \"%s\" (ETRN) failed: %s",
4945 etrn_command, strerror(errno));
4946 _exit(EXIT_FAILURE); /* paranoia */
4949 /* Obey this if smtp_serialize and the 2nd fork yielded non-zero. That
4950 is, we are in the first subprocess, after forking again. All we can do
4951 for a failing fork is to log it. Otherwise, wait for the 2nd process to
4952 complete, before removing the serialization. */
4955 log_write(0, LOG_MAIN|LOG_PANIC, "2nd fork for serialized ETRN "
4956 "failed: %s", strerror(errno));
4960 DEBUG(D_any) debug_printf("waiting for serialized ETRN process %d\n",
4962 (void)wait(&status);
4963 DEBUG(D_any) debug_printf("serialized ETRN process %d ended\n",
4967 enq_end(etrn_serialize_key);
4968 _exit(EXIT_SUCCESS);
4971 /* Back in the top level SMTP process. Check that we started a subprocess
4972 and restore the signal state. */
4976 log_write(0, LOG_MAIN|LOG_PANIC, "fork of process for ETRN failed: %s",
4978 smtp_printf("458 Unable to fork process\r\n");
4979 if (smtp_etrn_serialize) enq_end(etrn_serialize_key);
4983 if (user_msg == NULL) smtp_printf("250 OK\r\n");
4984 else smtp_user_msg(US"250", user_msg);
4987 signal(SIGCHLD, oldsignal);
4992 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4993 US"unexpected argument data");
4997 /* This currently happens only for NULLs, but could be extended. */
5000 done = synprot_error(L_smtp_syntax_error, 0, NULL, /* Just logs */
5001 US"NULL character(s) present (shown as '?')");
5002 smtp_printf("501 NULL characters are not allowed in SMTP commands\r\n");
5008 if (smtp_inend >= smtp_inbuffer + in_buffer_size)
5009 smtp_inend = smtp_inbuffer + in_buffer_size - 1;
5010 c = smtp_inend - smtp_inptr;
5011 if (c > 150) c = 150;
5013 incomplete_transaction_log(US"sync failure");
5014 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP protocol synchronization error "
5015 "(next input sent too soon: pipelining was%s advertised): "
5016 "rejected \"%s\" %s next input=\"%s\"",
5017 pipelining_advertised? "" : " not",
5018 smtp_cmd_buffer, host_and_ident(TRUE),
5019 string_printing(smtp_inptr));
5020 smtp_notquit_exit(US"synchronization-error", US"554",
5021 US"SMTP synchronization error");
5022 done = 1; /* Pretend eof - drops connection */
5026 case TOO_MANY_NONMAIL_CMD:
5027 s = smtp_cmd_buffer;
5028 while (*s != 0 && !isspace(*s)) s++;
5029 incomplete_transaction_log(US"too many non-mail commands");
5030 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
5031 "nonmail commands (last was \"%.*s\")", host_and_ident(FALSE),
5032 (int)(s - smtp_cmd_buffer), smtp_cmd_buffer);
5033 smtp_notquit_exit(US"bad-commands", US"554", US"Too many nonmail commands");
5034 done = 1; /* Pretend eof - drops connection */
5037 #ifdef EXPERIMENTAL_PROXY
5038 case PROXY_FAIL_IGNORE_CMD:
5039 smtp_printf("503 Command refused, required Proxy negotiation failed\r\n");
5044 if (unknown_command_count++ >= smtp_max_unknown_commands)
5046 log_write(L_smtp_syntax_error, LOG_MAIN,
5047 "SMTP syntax error in \"%s\" %s %s",
5048 string_printing(smtp_cmd_buffer), host_and_ident(TRUE),
5049 US"unrecognized command");
5050 incomplete_transaction_log(US"unrecognized command");
5051 smtp_notquit_exit(US"bad-commands", US"500",
5052 US"Too many unrecognized commands");
5054 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
5055 "unrecognized commands (last was \"%s\")", host_and_ident(FALSE),
5059 done = synprot_error(L_smtp_syntax_error, 500, NULL,
5060 US"unrecognized command");
5064 /* This label is used by goto's inside loops that want to break out to
5065 the end of the command-processing loop. */
5068 last_was_rej_mail = was_rej_mail; /* Remember some last commands for */
5069 last_was_rcpt = was_rcpt; /* protocol error handling */
5073 return done - 2; /* Convert yield values */
5078 /* End of smtp_in.c */