1 /*************************************************
2 * Exim - an Internet mail transport agent *
3 *************************************************/
5 /* Copyright (c) University of Cambridge 1995 - 2016 */
6 /* See the file NOTICE for conditions of use and distribution. */
8 /* Functions for handling an incoming SMTP call. */
15 /* Initialize for TCP wrappers if so configured. It appears that the macro
16 HAVE_IPV6 is used in some versions of the tcpd.h header, so we unset it before
17 including that header, and restore its value afterwards. */
19 #ifdef USE_TCP_WRAPPERS
22 #define EXIM_HAVE_IPV6
28 #define HAVE_IPV6 TRUE
31 int allow_severity = LOG_INFO;
32 int deny_severity = LOG_NOTICE;
33 uschar *tcp_wrappers_name;
37 /* Size of buffer for reading SMTP commands. We used to use 512, as defined
38 by RFC 821. However, RFC 1869 specifies that this must be increased for SMTP
39 commands that accept arguments, and this in particular applies to AUTH, where
40 the data can be quite long. More recently this value was 2048 in Exim;
41 however, RFC 4954 (circa 2007) recommends 12288 bytes to handle AUTH. Clients
42 such as Thunderbird will send an AUTH with an initial-response for GSSAPI.
43 The maximum size of a Kerberos ticket under Windows 2003 is 12000 bytes, and
44 we need room to handle large base64-encoded AUTHs for GSSAPI.
47 #define smtp_cmd_buffer_size 16384
49 /* Size of buffer for reading SMTP incoming packets */
51 #define in_buffer_size 8192
53 /* Structure for SMTP command list */
60 short int is_mail_cmd;
63 /* Codes for identifying commands. We order them so that those that come first
64 are those for which synchronization is always required. Checking this can help
68 /* These commands are required to be synchronized, i.e. to be the last in a
69 block of commands when pipelining. */
71 HELO_CMD, EHLO_CMD, DATA_CMD, /* These are listed in the pipelining */
72 VRFY_CMD, EXPN_CMD, NOOP_CMD, /* RFC as requiring synchronization */
73 ETRN_CMD, /* This by analogy with TURN from the RFC */
74 STARTTLS_CMD, /* Required by the STARTTLS RFC */
75 TLS_AUTH_CMD, /* auto-command at start of SSL */
77 /* This is a dummy to identify the non-sync commands when pipelining */
79 NON_SYNC_CMD_PIPELINING,
81 /* These commands need not be synchronized when pipelining */
83 MAIL_CMD, RCPT_CMD, RSET_CMD,
85 /* This is a dummy to identify the non-sync commands when not pipelining */
87 NON_SYNC_CMD_NON_PIPELINING,
89 /* I have been unable to find a statement about the use of pipelining
90 with AUTH, so to be on the safe side it is here, though I kind of feel
91 it should be up there with the synchronized commands. */
95 /* I'm not sure about these, but I don't think they matter. */
100 PROXY_FAIL_IGNORE_CMD,
103 /* These are specials that don't correspond to actual commands */
105 EOF_CMD, OTHER_CMD, BADARG_CMD, BADCHAR_CMD, BADSYN_CMD,
106 TOO_MANY_NONMAIL_CMD };
109 /* This is a convenience macro for adding the identity of an SMTP command
110 to the circular buffer that holds a list of the last n received. */
113 smtp_connection_had[smtp_ch_index++] = n; \
114 if (smtp_ch_index >= SMTP_HBUFF_SIZE) smtp_ch_index = 0
117 /*************************************************
118 * Local static variables *
119 *************************************************/
121 static auth_instance *authenticated_by;
122 static BOOL auth_advertised;
124 static BOOL tls_advertised;
126 static BOOL dsn_advertised;
128 static BOOL helo_required = FALSE;
129 static BOOL helo_verify = FALSE;
130 static BOOL helo_seen;
131 static BOOL helo_accept_junk;
132 static BOOL count_nonmail;
133 static BOOL pipelining_advertised;
134 static BOOL rcpt_smtp_response_same;
135 static BOOL rcpt_in_progress;
136 static int nonmail_command_count;
137 static BOOL smtp_exit_function_called = 0;
139 static BOOL smtputf8_advertised;
141 static int synprot_error_count;
142 static int unknown_command_count;
143 static int sync_cmd_limit;
144 static int smtp_write_error = 0;
146 static uschar *rcpt_smtp_response;
147 static uschar *smtp_data_buffer;
148 static uschar *smtp_cmd_data;
150 /* We need to know the position of RSET, HELO, EHLO, AUTH, and STARTTLS. Their
151 final fields of all except AUTH are forced TRUE at the start of a new message
152 setup, to allow one of each between messages that is not counted as a nonmail
153 command. (In fact, only one of HELO/EHLO is not counted.) Also, we have to
154 allow a new EHLO after starting up TLS.
156 AUTH is "falsely" labelled as a mail command initially, so that it doesn't get
157 counted. However, the flag is changed when AUTH is received, so that multiple
158 failing AUTHs will eventually hit the limit. After a successful AUTH, another
159 AUTH is already forbidden. After a TLS session is started, AUTH's flag is again
160 forced TRUE, to allow for the re-authentication that can happen at that point.
162 QUIT is also "falsely" labelled as a mail command so that it doesn't up the
163 count of non-mail commands and possibly provoke an error.
165 tls_auth is a pseudo-command, never expected in input. It is activated
166 on TLS startup and looks for a tls authenticator. */
168 static smtp_cmd_list cmd_list[] = {
169 /* name len cmd has_arg is_mail_cmd */
171 { "rset", sizeof("rset")-1, RSET_CMD, FALSE, FALSE }, /* First */
172 { "helo", sizeof("helo")-1, HELO_CMD, TRUE, FALSE },
173 { "ehlo", sizeof("ehlo")-1, EHLO_CMD, TRUE, FALSE },
174 { "auth", sizeof("auth")-1, AUTH_CMD, TRUE, TRUE },
176 { "starttls", sizeof("starttls")-1, STARTTLS_CMD, FALSE, FALSE },
177 { "tls_auth", 0, TLS_AUTH_CMD, FALSE, TRUE },
180 /* If you change anything above here, also fix the definitions below. */
182 { "mail from:", sizeof("mail from:")-1, MAIL_CMD, TRUE, TRUE },
183 { "rcpt to:", sizeof("rcpt to:")-1, RCPT_CMD, TRUE, TRUE },
184 { "data", sizeof("data")-1, DATA_CMD, FALSE, TRUE },
185 { "quit", sizeof("quit")-1, QUIT_CMD, FALSE, TRUE },
186 { "noop", sizeof("noop")-1, NOOP_CMD, TRUE, FALSE },
187 { "etrn", sizeof("etrn")-1, ETRN_CMD, TRUE, FALSE },
188 { "vrfy", sizeof("vrfy")-1, VRFY_CMD, TRUE, FALSE },
189 { "expn", sizeof("expn")-1, EXPN_CMD, TRUE, FALSE },
190 { "help", sizeof("help")-1, HELP_CMD, TRUE, FALSE }
193 static smtp_cmd_list *cmd_list_end =
194 cmd_list + sizeof(cmd_list)/sizeof(smtp_cmd_list);
196 #define CMD_LIST_RSET 0
197 #define CMD_LIST_HELO 1
198 #define CMD_LIST_EHLO 2
199 #define CMD_LIST_AUTH 3
200 #define CMD_LIST_STARTTLS 4
201 #define CMD_LIST_TLS_AUTH 5
203 /* This list of names is used for performing the smtp_no_mail logging action.
204 It must be kept in step with the SCH_xxx enumerations. */
206 static uschar *smtp_names[] =
208 US"NONE", US"AUTH", US"DATA", US"EHLO", US"ETRN", US"EXPN", US"HELO",
209 US"HELP", US"MAIL", US"NOOP", US"QUIT", US"RCPT", US"RSET", US"STARTTLS",
212 static uschar *protocols_local[] = {
213 US"local-smtp", /* HELO */
214 US"local-smtps", /* The rare case EHLO->STARTTLS->HELO */
215 US"local-esmtp", /* EHLO */
216 US"local-esmtps", /* EHLO->STARTTLS->EHLO */
217 US"local-esmtpa", /* EHLO->AUTH */
218 US"local-esmtpsa" /* EHLO->STARTTLS->EHLO->AUTH */
220 static uschar *protocols[] = {
222 US"smtps", /* The rare case EHLO->STARTTLS->HELO */
223 US"esmtp", /* EHLO */
224 US"esmtps", /* EHLO->STARTTLS->EHLO */
225 US"esmtpa", /* EHLO->AUTH */
226 US"esmtpsa" /* EHLO->STARTTLS->EHLO->AUTH */
231 #define pcrpted 1 /* added to pextend or pnormal */
232 #define pauthed 2 /* added to pextend */
234 /* Sanity check and validate optional args to MAIL FROM: envelope */
237 ENV_MAIL_OPT_SIZE, ENV_MAIL_OPT_BODY, ENV_MAIL_OPT_AUTH,
241 ENV_MAIL_OPT_RET, ENV_MAIL_OPT_ENVID,
247 uschar * name; /* option requested during MAIL cmd */
248 int value; /* enum type */
249 BOOL need_value; /* TRUE requires value (name=value pair format)
250 FALSE is a singleton */
252 static env_mail_type_t env_mail_type_list[] = {
253 { US"SIZE", ENV_MAIL_OPT_SIZE, TRUE },
254 { US"BODY", ENV_MAIL_OPT_BODY, TRUE },
255 { US"AUTH", ENV_MAIL_OPT_AUTH, TRUE },
257 { US"PRDR", ENV_MAIL_OPT_PRDR, FALSE },
259 { US"RET", ENV_MAIL_OPT_RET, TRUE },
260 { US"ENVID", ENV_MAIL_OPT_ENVID, TRUE },
262 { US"SMTPUTF8",ENV_MAIL_OPT_UTF8, FALSE }, /* rfc6531 */
264 /* keep this the last entry */
265 { US"NULL", ENV_MAIL_OPT_NULL, FALSE },
268 /* When reading SMTP from a remote host, we have to use our own versions of the
269 C input-reading functions, in order to be able to flush the SMTP output only
270 when about to read more data from the socket. This is the only way to get
271 optimal performance when the client is using pipelining. Flushing for every
272 command causes a separate packet and reply packet each time; saving all the
273 responses up (when pipelining) combines them into one packet and one response.
275 For simplicity, these functions are used for *all* SMTP input, not only when
276 receiving over a socket. However, after setting up a secure socket (SSL), input
277 is read via the OpenSSL library, and another set of functions is used instead
280 These functions are set in the receive_getc etc. variables and called with the
281 same interface as the C functions. However, since there can only ever be
282 one incoming SMTP call, we just use a single buffer and flags. There is no need
283 to implement a complicated private FILE-like structure.*/
285 static uschar *smtp_inbuffer;
286 static uschar *smtp_inptr;
287 static uschar *smtp_inend;
288 static int smtp_had_eof;
289 static int smtp_had_error;
292 /*************************************************
293 * SMTP version of getc() *
294 *************************************************/
296 /* This gets the next byte from the SMTP input buffer. If the buffer is empty,
297 it flushes the output, and refills the buffer, with a timeout. The signal
298 handler is set appropriately by the calling function. This function is not used
299 after a connection has negotated itself into an TLS/SSL state.
302 Returns: the next character or EOF
308 if (smtp_inptr >= smtp_inend)
312 if (smtp_receive_timeout > 0) alarm(smtp_receive_timeout);
313 rc = read(fileno(smtp_in), smtp_inbuffer, in_buffer_size);
318 /* Must put the error text in fixed store, because this might be during
319 header reading, where it releases unused store above the header. */
322 smtp_had_error = save_errno;
323 smtp_read_error = string_copy_malloc(
324 string_sprintf(" (error: %s)", strerror(save_errno)));
326 else smtp_had_eof = 1;
330 dkim_exim_verify_feed(smtp_inbuffer, rc);
332 smtp_inend = smtp_inbuffer + rc;
333 smtp_inptr = smtp_inbuffer;
335 return *smtp_inptr++;
340 /*************************************************
341 * SMTP version of ungetc() *
342 *************************************************/
344 /* Puts a character back in the input buffer. Only ever
350 Returns: the character
356 *(--smtp_inptr) = ch;
363 /*************************************************
364 * SMTP version of feof() *
365 *************************************************/
367 /* Tests for a previous EOF
370 Returns: non-zero if the eof flag is set
382 /*************************************************
383 * SMTP version of ferror() *
384 *************************************************/
386 /* Tests for a previous read error, and returns with errno
387 restored to what it was when the error was detected.
390 Returns: non-zero if the error flag is set
396 errno = smtp_had_error;
397 return smtp_had_error;
402 /*************************************************
403 * Test for characters in the SMTP buffer *
404 *************************************************/
406 /* Used at the end of a message
415 return smtp_inptr < smtp_inend;
420 /*************************************************
421 * Write formatted string to SMTP channel *
422 *************************************************/
424 /* This is a separate function so that we don't have to repeat everything for
425 TLS support or debugging. It is global so that the daemon and the
426 authentication functions can use it. It does not return any error indication,
427 because major problems such as dropped connections won't show up till an output
428 flush for non-TLS connections. The smtp_fflush() function is available for
429 checking that: for convenience, TLS output errors are remembered here so that
430 they are also picked up later by smtp_fflush().
434 ... optional arguments
440 smtp_printf(const char *format, ...)
444 va_start(ap, format);
445 smtp_vprintf(format, ap);
449 /* This is split off so that verify.c:respond_printf() can, in effect, call
450 smtp_printf(), bearing in mind that in C a vararg function can't directly
451 call another vararg function, only a function which accepts a va_list. */
454 smtp_vprintf(const char *format, va_list ap)
458 yield = string_vformat(big_buffer, big_buffer_size, format, ap);
462 void *reset_point = store_get(0);
463 uschar *msg_copy, *cr, *end;
464 msg_copy = string_copy(big_buffer);
465 end = msg_copy + Ustrlen(msg_copy);
466 while ((cr = Ustrchr(msg_copy, '\r')) != NULL) /* lose CRs */
467 memmove(cr, cr + 1, (end--) - cr);
468 debug_printf("SMTP>> %s", msg_copy);
469 store_reset(reset_point);
474 log_write(0, LOG_MAIN|LOG_PANIC, "string too large in smtp_printf()");
475 smtp_closedown(US"Unexpected error");
476 exim_exit(EXIT_FAILURE);
479 /* If this is the first output for a (non-batch) RCPT command, see if all RCPTs
480 have had the same. Note: this code is also present in smtp_respond(). It would
481 be tidier to have it only in one place, but when it was added, it was easier to
482 do it that way, so as not to have to mess with the code for the RCPT command,
483 which sometimes uses smtp_printf() and sometimes smtp_respond(). */
485 if (rcpt_in_progress)
487 if (rcpt_smtp_response == NULL)
488 rcpt_smtp_response = string_copy(big_buffer);
489 else if (rcpt_smtp_response_same &&
490 Ustrcmp(rcpt_smtp_response, big_buffer) != 0)
491 rcpt_smtp_response_same = FALSE;
492 rcpt_in_progress = FALSE;
495 /* Now write the string */
498 if (tls_in.active >= 0)
500 if (tls_write(TRUE, big_buffer, Ustrlen(big_buffer)) < 0)
501 smtp_write_error = -1;
506 if (fprintf(smtp_out, "%s", big_buffer) < 0) smtp_write_error = -1;
511 /*************************************************
512 * Flush SMTP out and check for error *
513 *************************************************/
515 /* This function isn't currently used within Exim (it detects errors when it
516 tries to read the next SMTP input), but is available for use in local_scan().
517 For non-TLS connections, it flushes the output and checks for errors. For
518 TLS-connections, it checks for a previously-detected TLS write error.
521 Returns: 0 for no error; -1 after an error
527 if (tls_in.active < 0 && fflush(smtp_out) != 0) smtp_write_error = -1;
528 return smtp_write_error;
533 /*************************************************
534 * SMTP command read timeout *
535 *************************************************/
537 /* Signal handler for timing out incoming SMTP commands. This attempts to
540 Argument: signal number (SIGALRM)
545 command_timeout_handler(int sig)
547 sig = sig; /* Keep picky compilers happy */
548 log_write(L_lost_incoming_connection,
549 LOG_MAIN, "SMTP command timeout on%s connection from %s",
550 (tls_in.active >= 0)? " TLS" : "",
551 host_and_ident(FALSE));
552 if (smtp_batched_input)
553 moan_smtp_batch(NULL, "421 SMTP command timeout"); /* Does not return */
554 smtp_notquit_exit(US"command-timeout", US"421",
555 US"%s: SMTP command timeout - closing connection", smtp_active_hostname);
556 exim_exit(EXIT_FAILURE);
561 /*************************************************
563 *************************************************/
565 /* Signal handler for handling SIGTERM. Again, try to finish tidily.
567 Argument: signal number (SIGTERM)
572 command_sigterm_handler(int sig)
574 sig = sig; /* Keep picky compilers happy */
575 log_write(0, LOG_MAIN, "%s closed after SIGTERM", smtp_get_connection_info());
576 if (smtp_batched_input)
577 moan_smtp_batch(NULL, "421 SIGTERM received"); /* Does not return */
578 smtp_notquit_exit(US"signal-exit", US"421",
579 US"%s: Service not available - closing connection", smtp_active_hostname);
580 exim_exit(EXIT_FAILURE);
587 /*************************************************
588 * Restore socket timeout to previous value *
589 *************************************************/
590 /* If the previous value was successfully retrieved, restore
591 it before returning control to the non-proxy routines
593 Arguments: fd - File descriptor for input
594 get_ok - Successfully retrieved previous values
595 tvtmp - Time struct with previous values
596 vslen - Length of time struct
600 restore_socket_timeout(int fd, int get_ok, struct timeval tvtmp, socklen_t vslen)
603 setsockopt(fd, SOL_SOCKET, SO_RCVTIMEO, (char *)&tvtmp, vslen);
606 /*************************************************
607 * Check if host is required proxy host *
608 *************************************************/
609 /* The function determines if inbound host will be a regular smtp host
610 or if it is configured that it must use Proxy Protocol.
617 check_proxy_protocol_host()
620 /* Cannot configure local connection as a proxy inbound */
621 if (sender_host_address == NULL) return proxy_session;
623 rc = verify_check_this_host(CUSS &hosts_proxy, NULL, NULL,
624 sender_host_address, NULL);
628 debug_printf("Detected proxy protocol configured host\n");
629 proxy_session = TRUE;
631 return proxy_session;
635 /*************************************************
636 * Setup host for proxy protocol *
637 *************************************************/
638 /* The function configures the connection based on a header from the
639 inbound host to use Proxy Protocol. The specification is very exact
640 so exit with an error if do not find the exact required pieces. This
641 includes an incorrect number of spaces separating args.
648 setup_proxy_protocol_host()
660 struct { /* TCP/UDP over IPv4, len = 12 */
666 struct { /* TCP/UDP over IPv6, len = 36 */
667 uint8_t src_addr[16];
668 uint8_t dst_addr[16];
672 struct { /* AF_UNIX sockets, len = 216 */
673 uschar src_addr[108];
674 uschar dst_addr[108];
680 /* Temp variables used in PPv2 address:port parsing */
682 char tmpip[INET_ADDRSTRLEN];
683 struct sockaddr_in tmpaddr;
684 char tmpip6[INET6_ADDRSTRLEN];
685 struct sockaddr_in6 tmpaddr6;
689 const char v2sig[12] = "\x0D\x0A\x0D\x0A\x00\x0D\x0A\x51\x55\x49\x54\x0A";
690 uschar *iptype; /* To display debug info */
693 struct timeval tvtmp;
695 vslen = sizeof(struct timeval);
697 fd = fileno(smtp_in);
699 /* Save current socket timeout values */
700 get_ok = getsockopt(fd, SOL_SOCKET, SO_RCVTIMEO, (char *)&tvtmp,
703 /* Proxy Protocol host must send header within a short time
704 (default 3 seconds) or it's considered invalid */
705 tv.tv_sec = PROXY_NEGOTIATION_TIMEOUT_SEC;
706 tv.tv_usec = PROXY_NEGOTIATION_TIMEOUT_USEC;
707 setsockopt(fd, SOL_SOCKET, SO_RCVTIMEO, (char *)&tv,
708 sizeof(struct timeval));
712 /* The inbound host was declared to be a Proxy Protocol host, so
713 don't do a PEEK into the data, actually slurp it up. */
714 ret = recv(fd, &hdr, sizeof(hdr), 0);
716 while (ret == -1 && errno == EINTR);
720 restore_socket_timeout(fd, get_ok, tvtmp, vslen);
721 return (errno == EAGAIN) ? 0 : ERRNO_PROXYFAIL;
725 memcmp(&hdr.v2, v2sig, 12) == 0)
729 /* May 2014: haproxy combined the version and command into one byte to
730 allow two full bytes for the length field in order to proxy SSL
731 connections. SSL Proxy is not supported in this version of Exim, but
732 must still seperate values here. */
733 ver = (hdr.v2.ver_cmd & 0xf0) >> 4;
734 cmd = (hdr.v2.ver_cmd & 0x0f);
738 DEBUG(D_receive) debug_printf("Invalid Proxy Protocol version: %d\n", ver);
741 DEBUG(D_receive) debug_printf("Detected PROXYv2 header\n");
742 /* The v2 header will always be 16 bytes per the spec. */
743 size = 16 + hdr.v2.len;
746 DEBUG(D_receive) debug_printf("Truncated or too large PROXYv2 header (%d/%d)\n",
752 case 0x01: /* PROXY command */
755 case 0x11: /* TCPv4 address type */
757 tmpaddr.sin_addr.s_addr = hdr.v2.addr.ip4.src_addr;
758 inet_ntop(AF_INET, &(tmpaddr.sin_addr), (char *)&tmpip, sizeof(tmpip));
759 if (!string_is_ip_address(US tmpip,NULL))
761 DEBUG(D_receive) debug_printf("Invalid %s source IP\n", iptype);
762 return ERRNO_PROXYFAIL;
764 proxy_local_address = sender_host_address;
765 sender_host_address = string_copy(US tmpip);
766 tmpport = ntohs(hdr.v2.addr.ip4.src_port);
767 proxy_local_port = sender_host_port;
768 sender_host_port = tmpport;
769 /* Save dest ip/port */
770 tmpaddr.sin_addr.s_addr = hdr.v2.addr.ip4.dst_addr;
771 inet_ntop(AF_INET, &(tmpaddr.sin_addr), (char *)&tmpip, sizeof(tmpip));
772 if (!string_is_ip_address(US tmpip,NULL))
774 DEBUG(D_receive) debug_printf("Invalid %s dest port\n", iptype);
775 return ERRNO_PROXYFAIL;
777 proxy_external_address = string_copy(US tmpip);
778 tmpport = ntohs(hdr.v2.addr.ip4.dst_port);
779 proxy_external_port = tmpport;
781 case 0x21: /* TCPv6 address type */
783 memmove(tmpaddr6.sin6_addr.s6_addr, hdr.v2.addr.ip6.src_addr, 16);
784 inet_ntop(AF_INET6, &(tmpaddr6.sin6_addr), (char *)&tmpip6, sizeof(tmpip6));
785 if (!string_is_ip_address(US tmpip6,NULL))
787 DEBUG(D_receive) debug_printf("Invalid %s source IP\n", iptype);
788 return ERRNO_PROXYFAIL;
790 proxy_local_address = sender_host_address;
791 sender_host_address = string_copy(US tmpip6);
792 tmpport = ntohs(hdr.v2.addr.ip6.src_port);
793 proxy_local_port = sender_host_port;
794 sender_host_port = tmpport;
795 /* Save dest ip/port */
796 memmove(tmpaddr6.sin6_addr.s6_addr, hdr.v2.addr.ip6.dst_addr, 16);
797 inet_ntop(AF_INET6, &(tmpaddr6.sin6_addr), (char *)&tmpip6, sizeof(tmpip6));
798 if (!string_is_ip_address(US tmpip6,NULL))
800 DEBUG(D_receive) debug_printf("Invalid %s dest port\n", iptype);
801 return ERRNO_PROXYFAIL;
803 proxy_external_address = string_copy(US tmpip6);
804 tmpport = ntohs(hdr.v2.addr.ip6.dst_port);
805 proxy_external_port = tmpport;
809 debug_printf("Unsupported PROXYv2 connection type: 0x%02x\n",
813 /* Unsupported protocol, keep local connection address */
815 case 0x00: /* LOCAL command */
816 /* Keep local connection address for LOCAL */
820 debug_printf("Unsupported PROXYv2 command: 0x%x\n", cmd);
825 memcmp(hdr.v1.line, "PROXY", 5) == 0)
827 uschar *p = string_copy(hdr.v1.line);
828 uschar *end = memchr(p, '\r', ret - 1);
829 uschar *sp; /* Utility variables follow */
833 if (!end || end[1] != '\n')
835 DEBUG(D_receive) debug_printf("Partial or invalid PROXY header\n");
838 *end = '\0'; /* Terminate the string */
839 size = end + 2 - hdr.v1.line; /* Skip header + CRLF */
840 DEBUG(D_receive) debug_printf("Detected PROXYv1 header\n");
841 /* Step through the string looking for the required fields. Ensure
842 strict adherance to required formatting, exit for any error. */
844 if (!isspace(*(p++)))
846 DEBUG(D_receive) debug_printf("Missing space after PROXY command\n");
849 if (!Ustrncmp(p, CCS"TCP4", 4))
851 else if (!Ustrncmp(p,CCS"TCP6", 4))
853 else if (!Ustrncmp(p,CCS"UNKNOWN", 7))
855 iptype = US"Unknown";
860 DEBUG(D_receive) debug_printf("Invalid TCP type\n");
864 p += Ustrlen(iptype);
865 if (!isspace(*(p++)))
867 DEBUG(D_receive) debug_printf("Missing space after TCP4/6 command\n");
870 /* Find the end of the arg */
871 if ((sp = Ustrchr(p, ' ')) == NULL)
874 debug_printf("Did not find proxied src %s\n", iptype);
878 if(!string_is_ip_address(p,NULL))
881 debug_printf("Proxied src arg is not an %s address\n", iptype);
884 proxy_local_address = sender_host_address;
885 sender_host_address = p;
887 if ((sp = Ustrchr(p, ' ')) == NULL)
890 debug_printf("Did not find proxy dest %s\n", iptype);
894 if(!string_is_ip_address(p,NULL))
897 debug_printf("Proxy dest arg is not an %s address\n", iptype);
900 proxy_external_address = p;
902 if ((sp = Ustrchr(p, ' ')) == NULL)
904 DEBUG(D_receive) debug_printf("Did not find proxied src port\n");
908 tmp_port = strtol(CCS p,&endc,10);
909 if (*endc || tmp_port == 0)
912 debug_printf("Proxied src port '%s' not an integer\n", p);
915 proxy_local_port = sender_host_port;
916 sender_host_port = tmp_port;
918 if ((sp = Ustrchr(p, '\0')) == NULL)
920 DEBUG(D_receive) debug_printf("Did not find proxy dest port\n");
923 tmp_port = strtol(CCS p,&endc,10);
924 if (*endc || tmp_port == 0)
927 debug_printf("Proxy dest port '%s' not an integer\n", p);
930 proxy_external_port = tmp_port;
931 /* Already checked for /r /n above. Good V1 header received. */
937 DEBUG(D_receive) debug_printf("Invalid proxy protocol version negotiation\n");
942 restore_socket_timeout(fd, get_ok, tvtmp, vslen);
943 /* Don't flush any potential buffer contents. Any input should cause a
944 synchronization failure */
948 restore_socket_timeout(fd, get_ok, tvtmp, vslen);
950 debug_printf("Valid %s sender from Proxy Protocol header\n", iptype);
951 return proxy_session;
955 /*************************************************
956 * Read one command line *
957 *************************************************/
959 /* Strictly, SMTP commands coming over the net are supposed to end with CRLF.
960 There are sites that don't do this, and in any case internal SMTP probably
961 should check only for LF. Consequently, we check here for LF only. The line
962 ends up with [CR]LF removed from its end. If we get an overlong line, treat as
963 an unknown command. The command is read into the global smtp_cmd_buffer so that
964 it is available via $smtp_command.
966 The character reading routine sets up a timeout for each block actually read
967 from the input (which may contain more than one command). We set up a special
968 signal handler that closes down the session on a timeout. Control does not
972 check_sync if TRUE, check synchronization rules if global option is TRUE
974 Returns: a code identifying the command (enumerated above)
978 smtp_read_command(BOOL check_sync)
983 BOOL hadnull = FALSE;
985 os_non_restarting_signal(SIGALRM, command_timeout_handler);
987 while ((c = (receive_getc)()) != '\n' && c != EOF)
989 if (ptr >= smtp_cmd_buffer_size)
991 os_non_restarting_signal(SIGALRM, sigalrm_handler);
999 smtp_cmd_buffer[ptr++] = c;
1002 receive_linecount++; /* For BSMTP errors */
1003 os_non_restarting_signal(SIGALRM, sigalrm_handler);
1005 /* If hit end of file, return pseudo EOF command. Whether we have a
1006 part-line already read doesn't matter, since this is an error state. */
1008 if (c == EOF) return EOF_CMD;
1010 /* Remove any CR and white space at the end of the line, and terminate the
1013 while (ptr > 0 && isspace(smtp_cmd_buffer[ptr-1])) ptr--;
1014 smtp_cmd_buffer[ptr] = 0;
1016 DEBUG(D_receive) debug_printf("SMTP<< %s\n", smtp_cmd_buffer);
1018 /* NULLs are not allowed in SMTP commands */
1020 if (hadnull) return BADCHAR_CMD;
1022 /* Scan command list and return identity, having set the data pointer
1023 to the start of the actual data characters. Check for SMTP synchronization
1026 for (p = cmd_list; p < cmd_list_end; p++)
1028 #ifdef SUPPORT_PROXY
1029 /* Only allow QUIT command if Proxy Protocol parsing failed */
1030 if (proxy_session && proxy_session_failed)
1032 if (p->cmd != QUIT_CMD)
1037 && strncmpic(smtp_cmd_buffer, US p->name, p->len) == 0
1038 && ( smtp_cmd_buffer[p->len-1] == ':' /* "mail from:" or "rcpt to:" */
1039 || smtp_cmd_buffer[p->len] == 0
1040 || smtp_cmd_buffer[p->len] == ' '
1043 if (smtp_inptr < smtp_inend && /* Outstanding input */
1044 p->cmd < sync_cmd_limit && /* Command should sync */
1045 check_sync && /* Local flag set */
1046 smtp_enforce_sync && /* Global flag set */
1047 sender_host_address != NULL && /* Not local input */
1048 !sender_host_notsocket) /* Really is a socket */
1051 /* The variables $smtp_command and $smtp_command_argument point into the
1052 unmodified input buffer. A copy of the latter is taken for actual
1053 processing, so that it can be chopped up into separate parts if necessary,
1054 for example, when processing a MAIL command options such as SIZE that can
1055 follow the sender address. */
1057 smtp_cmd_argument = smtp_cmd_buffer + p->len;
1058 while (isspace(*smtp_cmd_argument)) smtp_cmd_argument++;
1059 Ustrcpy(smtp_data_buffer, smtp_cmd_argument);
1060 smtp_cmd_data = smtp_data_buffer;
1062 /* Count non-mail commands from those hosts that are controlled in this
1063 way. The default is all hosts. We don't waste effort checking the list
1064 until we get a non-mail command, but then cache the result to save checking
1065 again. If there's a DEFER while checking the host, assume it's in the list.
1067 Note that one instance of RSET, EHLO/HELO, and STARTTLS is allowed at the
1068 start of each incoming message by fiddling with the value in the table. */
1070 if (!p->is_mail_cmd)
1072 if (count_nonmail == TRUE_UNSET) count_nonmail =
1073 verify_check_host(&smtp_accept_max_nonmail_hosts) != FAIL;
1074 if (count_nonmail && ++nonmail_command_count > smtp_accept_max_nonmail)
1075 return TOO_MANY_NONMAIL_CMD;
1078 /* If there is data for a command that does not expect it, generate the
1081 return (p->has_arg || *smtp_cmd_data == 0)? p->cmd : BADARG_CMD;
1085 #ifdef SUPPORT_PROXY
1086 /* Only allow QUIT command if Proxy Protocol parsing failed */
1087 if (proxy_session && proxy_session_failed)
1088 return PROXY_FAIL_IGNORE_CMD;
1091 /* Enforce synchronization for unknown commands */
1093 if (smtp_inptr < smtp_inend && /* Outstanding input */
1094 check_sync && /* Local flag set */
1095 smtp_enforce_sync && /* Global flag set */
1096 sender_host_address != NULL && /* Not local input */
1097 !sender_host_notsocket) /* Really is a socket */
1105 /*************************************************
1106 * Recheck synchronization *
1107 *************************************************/
1109 /* Synchronization checks can never be perfect because a packet may be on its
1110 way but not arrived when the check is done. Such checks can in any case only be
1111 done when TLS is not in use. Normally, the checks happen when commands are
1112 read: Exim ensures that there is no more input in the input buffer. In normal
1113 cases, the response to the command will be fast, and there is no further check.
1115 However, for some commands an ACL is run, and that can include delays. In those
1116 cases, it is useful to do another check on the input just before sending the
1117 response. This also applies at the start of a connection. This function does
1118 that check by means of the select() function, as long as the facility is not
1119 disabled or inappropriate. A failure of select() is ignored.
1121 When there is unwanted input, we read it so that it appears in the log of the
1125 Returns: TRUE if all is well; FALSE if there is input pending
1133 struct timeval tzero;
1135 if (!smtp_enforce_sync || sender_host_address == NULL ||
1136 sender_host_notsocket || tls_in.active >= 0)
1139 fd = fileno(smtp_in);
1144 rc = select(fd + 1, (SELECT_ARG2_TYPE *)&fds, NULL, NULL, &tzero);
1146 if (rc <= 0) return TRUE; /* Not ready to read */
1148 if (rc < 0) return TRUE; /* End of file or error */
1151 rc = smtp_inend - smtp_inptr;
1152 if (rc > 150) rc = 150;
1159 /*************************************************
1160 * Forced closedown of call *
1161 *************************************************/
1163 /* This function is called from log.c when Exim is dying because of a serious
1164 disaster, and also from some other places. If an incoming non-batched SMTP
1165 channel is open, it swallows the rest of the incoming message if in the DATA
1166 phase, sends the reply string, and gives an error to all subsequent commands
1167 except QUIT. The existence of an SMTP call is detected by the non-NULLness of
1171 message SMTP reply string to send, excluding the code
1177 smtp_closedown(uschar *message)
1179 if (smtp_in == NULL || smtp_batched_input) return;
1180 receive_swallow_smtp();
1181 smtp_printf("421 %s\r\n", message);
1185 switch(smtp_read_command(FALSE))
1191 smtp_printf("221 %s closing connection\r\n", smtp_active_hostname);
1196 smtp_printf("250 Reset OK\r\n");
1200 smtp_printf("421 %s\r\n", message);
1209 /*************************************************
1210 * Set up connection info for logging *
1211 *************************************************/
1213 /* This function is called when logging information about an SMTP connection.
1214 It sets up appropriate source information, depending on the type of connection.
1215 If sender_fullhost is NULL, we are at a very early stage of the connection;
1216 just use the IP address.
1219 Returns: a string describing the connection
1223 smtp_get_connection_info(void)
1225 uschar *hostname = (sender_fullhost == NULL)?
1226 sender_host_address : sender_fullhost;
1229 return string_sprintf("SMTP connection from %s", hostname);
1231 if (sender_host_unknown || sender_host_notsocket)
1232 return string_sprintf("SMTP connection from %s", sender_ident);
1235 return string_sprintf("SMTP connection from %s (via inetd)", hostname);
1237 if (LOGGING(incoming_interface) && interface_address != NULL)
1238 return string_sprintf("SMTP connection from %s I=[%s]:%d", hostname,
1239 interface_address, interface_port);
1241 return string_sprintf("SMTP connection from %s", hostname);
1247 /* Append TLS-related information to a log line
1250 s String under construction: allocated string to extend, or NULL
1251 sizep Pointer to current allocation size (update on return), or NULL
1252 ptrp Pointer to index for new entries in string (update on return), or NULL
1254 Returns: Allocated string or NULL
1257 s_tlslog(uschar * s, int * sizep, int * ptrp)
1259 int size = sizep ? *sizep : 0;
1260 int ptr = ptrp ? *ptrp : 0;
1262 if (LOGGING(tls_cipher) && tls_in.cipher != NULL)
1263 s = string_append(s, &size, &ptr, 2, US" X=", tls_in.cipher);
1264 if (LOGGING(tls_certificate_verified) && tls_in.cipher != NULL)
1265 s = string_append(s, &size, &ptr, 2, US" CV=",
1266 tls_in.certificate_verified? "yes":"no");
1267 if (LOGGING(tls_peerdn) && tls_in.peerdn != NULL)
1268 s = string_append(s, &size, &ptr, 3, US" DN=\"",
1269 string_printing(tls_in.peerdn), US"\"");
1270 if (LOGGING(tls_sni) && tls_in.sni != NULL)
1271 s = string_append(s, &size, &ptr, 3, US" SNI=\"",
1272 string_printing(tls_in.sni), US"\"");
1277 if (sizep) *sizep = size;
1278 if (ptrp) *ptrp = ptr;
1284 /*************************************************
1285 * Log lack of MAIL if so configured *
1286 *************************************************/
1288 /* This function is called when an SMTP session ends. If the log selector
1289 smtp_no_mail is set, write a log line giving some details of what has happened
1290 in the SMTP session.
1297 smtp_log_no_mail(void)
1302 if (smtp_mailcmd_count > 0 || !LOGGING(smtp_no_mail))
1308 if (sender_host_authenticated != NULL)
1310 s = string_append(s, &size, &ptr, 2, US" A=", sender_host_authenticated);
1311 if (authenticated_id != NULL)
1312 s = string_append(s, &size, &ptr, 2, US":", authenticated_id);
1316 s = s_tlslog(s, &size, &ptr);
1319 sep = (smtp_connection_had[SMTP_HBUFF_SIZE-1] != SCH_NONE)?
1320 US" C=..." : US" C=";
1321 for (i = smtp_ch_index; i < SMTP_HBUFF_SIZE; i++)
1323 if (smtp_connection_had[i] != SCH_NONE)
1325 s = string_append(s, &size, &ptr, 2, sep,
1326 smtp_names[smtp_connection_had[i]]);
1331 for (i = 0; i < smtp_ch_index; i++)
1333 s = string_append(s, &size, &ptr, 2, sep, smtp_names[smtp_connection_had[i]]);
1337 if (s != NULL) s[ptr] = 0; else s = US"";
1338 log_write(0, LOG_MAIN, "no MAIL in SMTP connection from %s D=%s%s",
1339 host_and_ident(FALSE),
1340 readconf_printtime( (int) ((long)time(NULL) - (long)smtp_connection_start)),
1346 /*************************************************
1347 * Check HELO line and set sender_helo_name *
1348 *************************************************/
1350 /* Check the format of a HELO line. The data for HELO/EHLO is supposed to be
1351 the domain name of the sending host, or an ip literal in square brackets. The
1352 arrgument is placed in sender_helo_name, which is in malloc store, because it
1353 must persist over multiple incoming messages. If helo_accept_junk is set, this
1354 host is permitted to send any old junk (needed for some broken hosts).
1355 Otherwise, helo_allow_chars can be used for rogue characters in general
1356 (typically people want to let in underscores).
1359 s the data portion of the line (already past any white space)
1361 Returns: TRUE or FALSE
1365 check_helo(uschar *s)
1368 uschar *end = s + Ustrlen(s);
1369 BOOL yield = helo_accept_junk;
1371 /* Discard any previous helo name */
1373 if (sender_helo_name != NULL)
1375 store_free(sender_helo_name);
1376 sender_helo_name = NULL;
1379 /* Skip tests if junk is permitted. */
1383 /* Allow the new standard form for IPv6 address literals, namely,
1384 [IPv6:....], and because someone is bound to use it, allow an equivalent
1385 IPv4 form. Allow plain addresses as well. */
1392 if (strncmpic(s, US"[IPv6:", 6) == 0)
1393 yield = (string_is_ip_address(s+6, NULL) == 6);
1394 else if (strncmpic(s, US"[IPv4:", 6) == 0)
1395 yield = (string_is_ip_address(s+6, NULL) == 4);
1397 yield = (string_is_ip_address(s+1, NULL) != 0);
1402 /* Non-literals must be alpha, dot, hyphen, plus any non-valid chars
1403 that have been configured (usually underscore - sigh). */
1410 if (!isalnum(*s) && *s != '.' && *s != '-' &&
1411 Ustrchr(helo_allow_chars, *s) == NULL)
1421 /* Save argument if OK */
1423 if (yield) sender_helo_name = string_copy_malloc(start);
1431 /*************************************************
1432 * Extract SMTP command option *
1433 *************************************************/
1435 /* This function picks the next option setting off the end of smtp_cmd_data. It
1436 is called for MAIL FROM and RCPT TO commands, to pick off the optional ESMTP
1437 things that can appear there.
1440 name point this at the name
1441 value point this at the data string
1443 Returns: TRUE if found an option
1447 extract_option(uschar **name, uschar **value)
1450 uschar *v = smtp_cmd_data + Ustrlen(smtp_cmd_data) - 1;
1451 while (isspace(*v)) v--;
1453 while (v > smtp_cmd_data && *v != '=' && !isspace(*v)) v--;
1458 while(isalpha(n[-1])) n--;
1459 /* RFC says SP, but TAB seen in wild and other major MTAs accept it */
1460 if (!isspace(n[-1])) return FALSE;
1466 if (v == smtp_cmd_data) return FALSE;
1478 /*************************************************
1479 * Reset for new message *
1480 *************************************************/
1482 /* This function is called whenever the SMTP session is reset from
1483 within either of the setup functions.
1485 Argument: the stacking pool storage reset point
1490 smtp_reset(void *reset_point)
1492 store_reset(reset_point);
1493 recipients_list = NULL;
1494 rcpt_count = rcpt_defer_count = rcpt_fail_count =
1495 raw_recipients_count = recipients_count = recipients_list_max = 0;
1496 cancel_cutthrough_connection("smtp reset");
1497 message_linecount = 0;
1499 acl_added_headers = NULL;
1500 acl_removed_headers = NULL;
1501 queue_only_policy = FALSE;
1502 rcpt_smtp_response = NULL;
1503 rcpt_smtp_response_same = TRUE;
1504 rcpt_in_progress = FALSE;
1505 deliver_freeze = FALSE; /* Can be set by ACL */
1506 freeze_tell = freeze_tell_config; /* Can be set by ACL */
1507 fake_response = OK; /* Can be set by ACL */
1508 #ifdef WITH_CONTENT_SCAN
1509 no_mbox_unspool = FALSE; /* Can be set by ACL */
1511 submission_mode = FALSE; /* Can be set by ACL */
1512 suppress_local_fixups = suppress_local_fixups_default; /* Can be set by ACL */
1513 active_local_from_check = local_from_check; /* Can be set by ACL */
1514 active_local_sender_retain = local_sender_retain; /* Can be set by ACL */
1515 sender_address = NULL;
1516 submission_name = NULL; /* Can be set by ACL */
1517 raw_sender = NULL; /* After SMTP rewrite, before qualifying */
1518 sender_address_unrewritten = NULL; /* Set only after verify rewrite */
1519 sender_verified_list = NULL; /* No senders verified */
1520 memset(sender_address_cache, 0, sizeof(sender_address_cache));
1521 memset(sender_domain_cache, 0, sizeof(sender_domain_cache));
1523 authenticated_sender = NULL;
1524 #ifdef EXPERIMENTAL_BRIGHTMAIL
1526 bmi_verdicts = NULL;
1528 #ifndef DISABLE_DKIM
1529 dkim_signers = NULL;
1530 dkim_disable_verify = FALSE;
1531 dkim_collect_input = FALSE;
1535 #ifndef DISABLE_PRDR
1536 prdr_requested = FALSE;
1538 #ifdef EXPERIMENTAL_SPF
1539 spf_header_comment = NULL;
1540 spf_received = NULL;
1542 spf_smtp_comment = NULL;
1545 message_smtputf8 = FALSE;
1547 body_linecount = body_zerocount = 0;
1549 sender_rate = sender_rate_limit = sender_rate_period = NULL;
1550 ratelimiters_mail = NULL; /* Updated by ratelimit ACL condition */
1551 /* Note that ratelimiters_conn persists across resets. */
1553 /* Reset message ACL variables */
1557 /* The message body variables use malloc store. They may be set if this is
1558 not the first message in an SMTP session and the previous message caused them
1559 to be referenced in an ACL. */
1561 if (message_body != NULL)
1563 store_free(message_body);
1564 message_body = NULL;
1567 if (message_body_end != NULL)
1569 store_free(message_body_end);
1570 message_body_end = NULL;
1573 /* Warning log messages are also saved in malloc store. They are saved to avoid
1574 repetition in the same message, but it seems right to repeat them for different
1577 while (acl_warn_logged != NULL)
1579 string_item *this = acl_warn_logged;
1580 acl_warn_logged = acl_warn_logged->next;
1589 /*************************************************
1590 * Initialize for incoming batched SMTP message *
1591 *************************************************/
1593 /* This function is called from smtp_setup_msg() in the case when
1594 smtp_batched_input is true. This happens when -bS is used to pass a whole batch
1595 of messages in one file with SMTP commands between them. All errors must be
1596 reported by sending a message, and only MAIL FROM, RCPT TO, and DATA are
1597 relevant. After an error on a sender, or an invalid recipient, the remainder
1598 of the message is skipped. The value of received_protocol is already set.
1601 Returns: > 0 message successfully started (reached DATA)
1602 = 0 QUIT read or end of file reached
1603 < 0 should not occur
1607 smtp_setup_batch_msg(void)
1610 void *reset_point = store_get(0);
1612 /* Save the line count at the start of each transaction - single commands
1613 like HELO and RSET count as whole transactions. */
1615 bsmtp_transaction_linecount = receive_linecount;
1617 if ((receive_feof)()) return 0; /* Treat EOF as QUIT */
1619 smtp_reset(reset_point); /* Reset for start of message */
1621 /* Deal with SMTP commands. This loop is exited by setting done to a POSITIVE
1622 value. The values are 2 larger than the required yield of the function. */
1627 uschar *recipient = NULL;
1628 int start, end, sender_domain, recipient_domain;
1630 switch(smtp_read_command(FALSE))
1632 /* The HELO/EHLO commands set sender_address_helo if they have
1633 valid data; otherwise they are ignored, except that they do
1634 a reset of the state. */
1639 check_helo(smtp_cmd_data);
1643 smtp_reset(reset_point);
1644 bsmtp_transaction_linecount = receive_linecount;
1648 /* The MAIL FROM command requires an address as an operand. All we
1649 do here is to parse it for syntactic correctness. The form "<>" is
1650 a special case which converts into an empty string. The start/end
1651 pointers in the original are not used further for this address, as
1652 it is the canonical extracted address which is all that is kept. */
1655 smtp_mailcmd_count++; /* Count for no-mail log */
1656 if (sender_address != NULL)
1657 /* The function moan_smtp_batch() does not return. */
1658 moan_smtp_batch(smtp_cmd_buffer, "503 Sender already given");
1660 if (smtp_cmd_data[0] == 0)
1661 /* The function moan_smtp_batch() does not return. */
1662 moan_smtp_batch(smtp_cmd_buffer, "501 MAIL FROM must have an address operand");
1664 /* Reset to start of message */
1666 smtp_reset(reset_point);
1668 /* Apply SMTP rewrite */
1670 raw_sender = ((rewrite_existflags & rewrite_smtp) != 0)?
1671 rewrite_one(smtp_cmd_data, rewrite_smtp|rewrite_smtp_sender, NULL, FALSE,
1672 US"", global_rewrite_rules) : smtp_cmd_data;
1674 /* Extract the address; the TRUE flag allows <> as valid */
1677 parse_extract_address(raw_sender, &errmess, &start, &end, &sender_domain,
1680 if (raw_sender == NULL)
1681 /* The function moan_smtp_batch() does not return. */
1682 moan_smtp_batch(smtp_cmd_buffer, "501 %s", errmess);
1684 sender_address = string_copy(raw_sender);
1686 /* Qualify unqualified sender addresses if permitted to do so. */
1688 if (sender_domain == 0 && sender_address[0] != 0 && sender_address[0] != '@')
1690 if (allow_unqualified_sender)
1692 sender_address = rewrite_address_qualify(sender_address, FALSE);
1693 DEBUG(D_receive) debug_printf("unqualified address %s accepted "
1694 "and rewritten\n", raw_sender);
1696 /* The function moan_smtp_batch() does not return. */
1697 else moan_smtp_batch(smtp_cmd_buffer, "501 sender address must contain "
1703 /* The RCPT TO command requires an address as an operand. All we do
1704 here is to parse it for syntactic correctness. There may be any number
1705 of RCPT TO commands, specifying multiple senders. We build them all into
1706 a data structure that is in argc/argv format. The start/end values
1707 given by parse_extract_address are not used, as we keep only the
1708 extracted address. */
1711 if (sender_address == NULL)
1712 /* The function moan_smtp_batch() does not return. */
1713 moan_smtp_batch(smtp_cmd_buffer, "503 No sender yet given");
1715 if (smtp_cmd_data[0] == 0)
1716 /* The function moan_smtp_batch() does not return. */
1717 moan_smtp_batch(smtp_cmd_buffer, "501 RCPT TO must have an address operand");
1719 /* Check maximum number allowed */
1721 if (recipients_max > 0 && recipients_count + 1 > recipients_max)
1722 /* The function moan_smtp_batch() does not return. */
1723 moan_smtp_batch(smtp_cmd_buffer, "%s too many recipients",
1724 recipients_max_reject? "552": "452");
1726 /* Apply SMTP rewrite, then extract address. Don't allow "<>" as a
1727 recipient address */
1729 recipient = rewrite_existflags & rewrite_smtp
1730 ? rewrite_one(smtp_cmd_data, rewrite_smtp, NULL, FALSE, US"",
1731 global_rewrite_rules)
1734 recipient = parse_extract_address(recipient, &errmess, &start, &end,
1735 &recipient_domain, FALSE);
1738 /* The function moan_smtp_batch() does not return. */
1739 moan_smtp_batch(smtp_cmd_buffer, "501 %s", errmess);
1741 /* If the recipient address is unqualified, qualify it if permitted. Then
1742 add it to the list of recipients. */
1744 if (recipient_domain == 0)
1746 if (allow_unqualified_recipient)
1748 DEBUG(D_receive) debug_printf("unqualified address %s accepted\n",
1750 recipient = rewrite_address_qualify(recipient, TRUE);
1752 /* The function moan_smtp_batch() does not return. */
1753 else moan_smtp_batch(smtp_cmd_buffer, "501 recipient address must contain "
1756 receive_add_recipient(recipient, -1);
1760 /* The DATA command is legal only if it follows successful MAIL FROM
1761 and RCPT TO commands. This function is complete when a valid DATA
1762 command is encountered. */
1765 if (sender_address == NULL || recipients_count <= 0)
1767 /* The function moan_smtp_batch() does not return. */
1768 if (sender_address == NULL)
1769 moan_smtp_batch(smtp_cmd_buffer,
1770 "503 MAIL FROM:<sender> command must precede DATA");
1772 moan_smtp_batch(smtp_cmd_buffer,
1773 "503 RCPT TO:<recipient> must precede DATA");
1777 done = 3; /* DATA successfully achieved */
1778 message_ended = END_NOTENDED; /* Indicate in middle of message */
1783 /* The VRFY, EXPN, HELP, ETRN, and NOOP commands are ignored. */
1790 bsmtp_transaction_linecount = receive_linecount;
1801 /* The function moan_smtp_batch() does not return. */
1802 moan_smtp_batch(smtp_cmd_buffer, "501 Unexpected argument data");
1807 /* The function moan_smtp_batch() does not return. */
1808 moan_smtp_batch(smtp_cmd_buffer, "501 Unexpected NULL in SMTP command");
1813 /* The function moan_smtp_batch() does not return. */
1814 moan_smtp_batch(smtp_cmd_buffer, "500 Command unrecognized");
1819 return done - 2; /* Convert yield values */
1825 /*************************************************
1826 * Start an SMTP session *
1827 *************************************************/
1829 /* This function is called at the start of an SMTP session. Thereafter,
1830 smtp_setup_msg() is called to initiate each separate message. This
1831 function does host-specific testing, and outputs the banner line.
1834 Returns: FALSE if the session can not continue; something has
1835 gone wrong, or the connection to the host is blocked
1839 smtp_start_session(void)
1843 uschar *user_msg, *log_msg;
1847 smtp_connection_start = time(NULL);
1848 for (smtp_ch_index = 0; smtp_ch_index < SMTP_HBUFF_SIZE; smtp_ch_index++)
1849 smtp_connection_had[smtp_ch_index] = SCH_NONE;
1852 /* Default values for certain variables */
1854 helo_seen = esmtp = helo_accept_junk = FALSE;
1855 smtp_mailcmd_count = 0;
1856 count_nonmail = TRUE_UNSET;
1857 synprot_error_count = unknown_command_count = nonmail_command_count = 0;
1858 smtp_delay_mail = smtp_rlm_base;
1859 auth_advertised = FALSE;
1860 pipelining_advertised = FALSE;
1861 pipelining_enable = TRUE;
1862 sync_cmd_limit = NON_SYNC_CMD_NON_PIPELINING;
1863 smtp_exit_function_called = FALSE; /* For avoiding loop in not-quit exit */
1865 /* If receiving by -bs from a trusted user, or testing with -bh, we allow
1866 authentication settings from -oMaa to remain in force. */
1868 if (!host_checking && !sender_host_notsocket) sender_host_authenticated = NULL;
1869 authenticated_by = NULL;
1872 tls_in.cipher = tls_in.peerdn = NULL;
1873 tls_in.ourcert = tls_in.peercert = NULL;
1875 tls_in.ocsp = OCSP_NOT_REQ;
1876 tls_advertised = FALSE;
1878 dsn_advertised = FALSE;
1880 smtputf8_advertised = FALSE;
1883 /* Reset ACL connection variables */
1887 /* Allow for trailing 0 in the command and data buffers. */
1889 smtp_cmd_buffer = (uschar *)malloc(2*smtp_cmd_buffer_size + 2);
1890 if (smtp_cmd_buffer == NULL)
1891 log_write(0, LOG_MAIN|LOG_PANIC_DIE,
1892 "malloc() failed for SMTP command buffer");
1893 smtp_cmd_buffer[0] = 0;
1894 smtp_data_buffer = smtp_cmd_buffer + smtp_cmd_buffer_size + 1;
1896 /* For batched input, the protocol setting can be overridden from the
1897 command line by a trusted caller. */
1899 if (smtp_batched_input)
1901 if (received_protocol == NULL) received_protocol = US"local-bsmtp";
1904 /* For non-batched SMTP input, the protocol setting is forced here. It will be
1905 reset later if any of EHLO/AUTH/STARTTLS are received. */
1909 (sender_host_address ? protocols : protocols_local) [pnormal];
1911 /* Set up the buffer for inputting using direct read() calls, and arrange to
1912 call the local functions instead of the standard C ones. */
1914 smtp_inbuffer = (uschar *)malloc(in_buffer_size);
1915 if (smtp_inbuffer == NULL)
1916 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "malloc() failed for SMTP input buffer");
1917 receive_getc = smtp_getc;
1918 receive_ungetc = smtp_ungetc;
1919 receive_feof = smtp_feof;
1920 receive_ferror = smtp_ferror;
1921 receive_smtp_buffered = smtp_buffered;
1922 smtp_inptr = smtp_inend = smtp_inbuffer;
1923 smtp_had_eof = smtp_had_error = 0;
1925 /* Set up the message size limit; this may be host-specific */
1927 thismessage_size_limit = expand_string_integer(message_size_limit, TRUE);
1928 if (expand_string_message != NULL)
1930 if (thismessage_size_limit == -1)
1931 log_write(0, LOG_MAIN|LOG_PANIC, "unable to expand message_size_limit: "
1932 "%s", expand_string_message);
1934 log_write(0, LOG_MAIN|LOG_PANIC, "invalid message_size_limit: "
1935 "%s", expand_string_message);
1936 smtp_closedown(US"Temporary local problem - please try later");
1940 /* When a message is input locally via the -bs or -bS options, sender_host_
1941 unknown is set unless -oMa was used to force an IP address, in which case it
1942 is checked like a real remote connection. When -bs is used from inetd, this
1943 flag is not set, causing the sending host to be checked. The code that deals
1944 with IP source routing (if configured) is never required for -bs or -bS and
1945 the flag sender_host_notsocket is used to suppress it.
1947 If smtp_accept_max and smtp_accept_reserve are set, keep some connections in
1948 reserve for certain hosts and/or networks. */
1950 if (!sender_host_unknown)
1953 BOOL reserved_host = FALSE;
1955 /* Look up IP options (source routing info) on the socket if this is not an
1956 -oMa "host", and if any are found, log them and drop the connection.
1958 Linux (and others now, see below) is different to everyone else, so there
1959 has to be some conditional compilation here. Versions of Linux before 2.1.15
1960 used a structure whose name was "options". Somebody finally realized that
1961 this name was silly, and it got changed to "ip_options". I use the
1962 newer name here, but there is a fudge in the script that sets up os.h
1963 to define a macro in older Linux systems.
1965 Sigh. Linux is a fast-moving target. Another generation of Linux uses
1966 glibc 2, which has chosen ip_opts for the structure name. This is now
1967 really a glibc thing rather than a Linux thing, so the condition name
1968 has been changed to reflect this. It is relevant also to GNU/Hurd.
1970 Mac OS 10.x (Darwin) is like the later glibc versions, but without the
1971 setting of the __GLIBC__ macro, so we can't detect it automatically. There's
1972 a special macro defined in the os.h file.
1974 Some DGUX versions on older hardware appear not to support IP options at
1975 all, so there is now a general macro which can be set to cut out this
1978 How to do this properly in IPv6 is not yet known. */
1980 #if !HAVE_IPV6 && !defined(NO_IP_OPTIONS)
1982 #ifdef GLIBC_IP_OPTIONS
1983 #if (!defined __GLIBC__) || (__GLIBC__ < 2)
1988 #elif defined DARWIN_IP_OPTIONS
1994 if (!host_checking && !sender_host_notsocket)
1997 EXIM_SOCKLEN_T optlen = sizeof(struct ip_options) + MAX_IPOPTLEN;
1998 struct ip_options *ipopt = store_get(optlen);
2000 struct ip_opts ipoptblock;
2001 struct ip_opts *ipopt = &ipoptblock;
2002 EXIM_SOCKLEN_T optlen = sizeof(ipoptblock);
2004 struct ipoption ipoptblock;
2005 struct ipoption *ipopt = &ipoptblock;
2006 EXIM_SOCKLEN_T optlen = sizeof(ipoptblock);
2009 /* Occasional genuine failures of getsockopt() have been seen - for
2010 example, "reset by peer". Therefore, just log and give up on this
2011 call, unless the error is ENOPROTOOPT. This error is given by systems
2012 that have the interfaces but not the mechanism - e.g. GNU/Hurd at the time
2013 of writing. So for that error, carry on - we just can't do an IP options
2016 DEBUG(D_receive) debug_printf("checking for IP options\n");
2018 if (getsockopt(fileno(smtp_out), IPPROTO_IP, IP_OPTIONS, (uschar *)(ipopt),
2021 if (errno != ENOPROTOOPT)
2023 log_write(0, LOG_MAIN, "getsockopt() failed from %s: %s",
2024 host_and_ident(FALSE), strerror(errno));
2025 smtp_printf("451 SMTP service not available\r\n");
2030 /* Deal with any IP options that are set. On the systems I have looked at,
2031 the value of MAX_IPOPTLEN has been 40, meaning that there should never be
2032 more logging data than will fit in big_buffer. Nevertheless, after somebody
2033 questioned this code, I've added in some paranoid checking. */
2035 else if (optlen > 0)
2037 uschar *p = big_buffer;
2038 uschar *pend = big_buffer + big_buffer_size;
2039 uschar *opt, *adptr;
2041 struct in_addr addr;
2044 uschar *optstart = (uschar *)(ipopt->__data);
2046 uschar *optstart = (uschar *)(ipopt->ip_opts);
2048 uschar *optstart = (uschar *)(ipopt->ipopt_list);
2051 DEBUG(D_receive) debug_printf("IP options exist\n");
2053 Ustrcpy(p, "IP options on incoming call:");
2056 for (opt = optstart; opt != NULL &&
2057 opt < (uschar *)(ipopt) + optlen;)
2071 if (!string_format(p, pend-p, " %s [@%s",
2072 (*opt == IPOPT_SSRR)? "SSRR" : "LSRR",
2074 inet_ntoa(*((struct in_addr *)(&(ipopt->faddr))))))
2076 inet_ntoa(ipopt->ip_dst)))
2078 inet_ntoa(ipopt->ipopt_dst)))
2086 optcount = (opt[1] - 3) / sizeof(struct in_addr);
2088 while (optcount-- > 0)
2090 memcpy(&addr, adptr, sizeof(addr));
2091 if (!string_format(p, pend - p - 1, "%s%s",
2092 (optcount == 0)? ":" : "@", inet_ntoa(addr)))
2098 adptr += sizeof(struct in_addr);
2107 if (pend - p < 4 + 3*opt[1]) { opt = NULL; break; }
2110 for (i = 0; i < opt[1]; i++)
2112 sprintf(CS p, "%2.2x ", opt[i]);
2123 log_write(0, LOG_MAIN, "%s", big_buffer);
2125 /* Refuse any call with IP options. This is what tcpwrappers 7.5 does. */
2127 log_write(0, LOG_MAIN|LOG_REJECT,
2128 "connection from %s refused (IP options)", host_and_ident(FALSE));
2130 smtp_printf("554 SMTP service not available\r\n");
2134 /* Length of options = 0 => there are no options */
2136 else DEBUG(D_receive) debug_printf("no IP options found\n");
2138 #endif /* HAVE_IPV6 && !defined(NO_IP_OPTIONS) */
2140 /* Set keep-alive in socket options. The option is on by default. This
2141 setting is an attempt to get rid of some hanging connections that stick in
2142 read() when the remote end (usually a dialup) goes away. */
2144 if (smtp_accept_keepalive && !sender_host_notsocket)
2145 ip_keepalive(fileno(smtp_out), sender_host_address, FALSE);
2147 /* If the current host matches host_lookup, set the name by doing a
2148 reverse lookup. On failure, sender_host_name will be NULL and
2149 host_lookup_failed will be TRUE. This may or may not be serious - optional
2152 if (verify_check_host(&host_lookup) == OK)
2154 (void)host_name_lookup();
2155 host_build_sender_fullhost();
2158 /* Delay this until we have the full name, if it is looked up. */
2160 set_process_info("handling incoming connection from %s",
2161 host_and_ident(FALSE));
2163 /* Expand smtp_receive_timeout, if needed */
2165 if (smtp_receive_timeout_s)
2168 if ( !(exp = expand_string(smtp_receive_timeout_s))
2170 || (smtp_receive_timeout = readconf_readtime(exp, 0, FALSE)) < 0
2172 log_write(0, LOG_MAIN|LOG_PANIC,
2173 "bad value for smtp_receive_timeout: '%s'", exp ? exp : US"");
2176 /* Start up TLS if tls_on_connect is set. This is for supporting the legacy
2177 smtps port for use with older style SSL MTAs. */
2180 if (tls_in.on_connect && tls_server_start(tls_require_ciphers) != OK)
2184 /* Test for explicit connection rejection */
2186 if (verify_check_host(&host_reject_connection) == OK)
2188 log_write(L_connection_reject, LOG_MAIN|LOG_REJECT, "refused connection "
2189 "from %s (host_reject_connection)", host_and_ident(FALSE));
2190 smtp_printf("554 SMTP service not available\r\n");
2194 /* Test with TCP Wrappers if so configured. There is a problem in that
2195 hosts_ctl() returns 0 (deny) under a number of system failure circumstances,
2196 such as disks dying. In these cases, it is desirable to reject with a 4xx
2197 error instead of a 5xx error. There isn't a "right" way to detect such
2198 problems. The following kludge is used: errno is zeroed before calling
2199 hosts_ctl(). If the result is "reject", a 5xx error is given only if the
2200 value of errno is 0 or ENOENT (which happens if /etc/hosts.{allow,deny} does
2203 #ifdef USE_TCP_WRAPPERS
2205 tcp_wrappers_name = expand_string(tcp_wrappers_daemon_name);
2206 if (tcp_wrappers_name == NULL)
2208 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "Expansion of \"%s\" "
2209 "(tcp_wrappers_name) failed: %s", string_printing(tcp_wrappers_name),
2210 expand_string_message);
2212 if (!hosts_ctl(tcp_wrappers_name,
2213 (sender_host_name == NULL)? STRING_UNKNOWN : CS sender_host_name,
2214 (sender_host_address == NULL)? STRING_UNKNOWN : CS sender_host_address,
2215 (sender_ident == NULL)? STRING_UNKNOWN : CS sender_ident))
2217 if (errno == 0 || errno == ENOENT)
2219 HDEBUG(D_receive) debug_printf("tcp wrappers rejection\n");
2220 log_write(L_connection_reject,
2221 LOG_MAIN|LOG_REJECT, "refused connection from %s "
2222 "(tcp wrappers)", host_and_ident(FALSE));
2223 smtp_printf("554 SMTP service not available\r\n");
2227 int save_errno = errno;
2228 HDEBUG(D_receive) debug_printf("tcp wrappers rejected with unexpected "
2229 "errno value %d\n", save_errno);
2230 log_write(L_connection_reject,
2231 LOG_MAIN|LOG_REJECT, "temporarily refused connection from %s "
2232 "(tcp wrappers errno=%d)", host_and_ident(FALSE), save_errno);
2233 smtp_printf("451 Temporary local problem - please try later\r\n");
2239 /* Check for reserved slots. The value of smtp_accept_count has already been
2240 incremented to include this process. */
2242 if (smtp_accept_max > 0 &&
2243 smtp_accept_count > smtp_accept_max - smtp_accept_reserve)
2245 if ((rc = verify_check_host(&smtp_reserve_hosts)) != OK)
2247 log_write(L_connection_reject,
2248 LOG_MAIN, "temporarily refused connection from %s: not in "
2249 "reserve list: connected=%d max=%d reserve=%d%s",
2250 host_and_ident(FALSE), smtp_accept_count - 1, smtp_accept_max,
2251 smtp_accept_reserve, (rc == DEFER)? " (lookup deferred)" : "");
2252 smtp_printf("421 %s: Too many concurrent SMTP connections; "
2253 "please try again later\r\n", smtp_active_hostname);
2256 reserved_host = TRUE;
2259 /* If a load level above which only messages from reserved hosts are
2260 accepted is set, check the load. For incoming calls via the daemon, the
2261 check is done in the superior process if there are no reserved hosts, to
2262 save a fork. In all cases, the load average will already be available
2263 in a global variable at this point. */
2265 if (smtp_load_reserve >= 0 &&
2266 load_average > smtp_load_reserve &&
2268 verify_check_host(&smtp_reserve_hosts) != OK)
2270 log_write(L_connection_reject,
2271 LOG_MAIN, "temporarily refused connection from %s: not in "
2272 "reserve list and load average = %.2f", host_and_ident(FALSE),
2273 (double)load_average/1000.0);
2274 smtp_printf("421 %s: Too much load; please try again later\r\n",
2275 smtp_active_hostname);
2279 /* Determine whether unqualified senders or recipients are permitted
2280 for this host. Unfortunately, we have to do this every time, in order to
2281 set the flags so that they can be inspected when considering qualifying
2282 addresses in the headers. For a site that permits no qualification, this
2283 won't take long, however. */
2285 allow_unqualified_sender =
2286 verify_check_host(&sender_unqualified_hosts) == OK;
2288 allow_unqualified_recipient =
2289 verify_check_host(&recipient_unqualified_hosts) == OK;
2291 /* Determine whether HELO/EHLO is required for this host. The requirement
2292 can be hard or soft. */
2294 helo_required = verify_check_host(&helo_verify_hosts) == OK;
2296 helo_verify = verify_check_host(&helo_try_verify_hosts) == OK;
2298 /* Determine whether this hosts is permitted to send syntactic junk
2299 after a HELO or EHLO command. */
2301 helo_accept_junk = verify_check_host(&helo_accept_junk_hosts) == OK;
2304 /* For batch SMTP input we are now done. */
2306 if (smtp_batched_input) return TRUE;
2308 #ifdef SUPPORT_PROXY
2309 /* If valid Proxy Protocol source is connecting, set up session.
2310 * Failure will not allow any SMTP function other than QUIT. */
2311 proxy_session = FALSE;
2312 proxy_session_failed = FALSE;
2313 if (check_proxy_protocol_host())
2315 if (setup_proxy_protocol_host() == FALSE)
2317 proxy_session_failed = TRUE;
2319 debug_printf("Failure to extract proxied host, only QUIT allowed\n");
2323 sender_host_name = NULL;
2324 (void)host_name_lookup();
2325 host_build_sender_fullhost();
2330 /* Run the ACL if it exists */
2333 if (acl_smtp_connect != NULL)
2336 rc = acl_check(ACL_WHERE_CONNECT, NULL, acl_smtp_connect, &user_msg,
2340 (void)smtp_handle_acl_fail(ACL_WHERE_CONNECT, rc, user_msg, log_msg);
2345 /* Output the initial message for a two-way SMTP connection. It may contain
2346 newlines, which then cause a multi-line response to be given. */
2348 code = US"220"; /* Default status code */
2349 esc = US""; /* Default extended status code */
2350 esclen = 0; /* Length of esc */
2354 if (!(s = expand_string(smtp_banner)))
2355 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "Expansion of \"%s\" (smtp_banner) "
2356 "failed: %s", smtp_banner, expand_string_message);
2362 smtp_message_code(&code, &codelen, &s, NULL, TRUE);
2366 esclen = codelen - 4;
2370 /* Remove any terminating newlines; might as well remove trailing space too */
2373 while (p > s && isspace(p[-1])) p--;
2376 /* It seems that CC:Mail is braindead, and assumes that the greeting message
2377 is all contained in a single IP packet. The original code wrote out the
2378 greeting using several calls to fprint/fputc, and on busy servers this could
2379 cause it to be split over more than one packet - which caused CC:Mail to fall
2380 over when it got the second part of the greeting after sending its first
2381 command. Sigh. To try to avoid this, build the complete greeting message
2382 first, and output it in one fell swoop. This gives a better chance of it
2383 ending up as a single packet. */
2385 ss = store_get(size);
2389 do /* At least once, in case we have an empty string */
2392 uschar *linebreak = Ustrchr(p, '\n');
2393 ss = string_catn(ss, &size, &ptr, code, 3);
2394 if (linebreak == NULL)
2397 ss = string_catn(ss, &size, &ptr, US" ", 1);
2401 len = linebreak - p;
2402 ss = string_catn(ss, &size, &ptr, US"-", 1);
2404 ss = string_catn(ss, &size, &ptr, esc, esclen);
2405 ss = string_catn(ss, &size, &ptr, p, len);
2406 ss = string_catn(ss, &size, &ptr, US"\r\n", 2);
2408 if (linebreak != NULL) p++;
2412 ss[ptr] = 0; /* string_cat leaves room for this */
2414 /* Before we write the banner, check that there is no input pending, unless
2415 this synchronisation check is disabled. */
2419 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP protocol "
2420 "synchronization error (input sent without waiting for greeting): "
2421 "rejected connection from %s input=\"%s\"", host_and_ident(TRUE),
2422 string_printing(smtp_inptr));
2423 smtp_printf("554 SMTP synchronization error\r\n");
2427 /* Now output the banner */
2429 smtp_printf("%s", ss);
2437 /*************************************************
2438 * Handle SMTP syntax and protocol errors *
2439 *************************************************/
2441 /* Write to the log for SMTP syntax errors in incoming commands, if configured
2442 to do so. Then transmit the error response. The return value depends on the
2443 number of syntax and protocol errors in this SMTP session.
2446 type error type, given as a log flag bit
2447 code response code; <= 0 means don't send a response
2448 data data to reflect in the response (can be NULL)
2449 errmess the error message
2451 Returns: -1 limit of syntax/protocol errors NOT exceeded
2452 +1 limit of syntax/protocol errors IS exceeded
2454 These values fit in with the values of the "done" variable in the main
2455 processing loop in smtp_setup_msg(). */
2458 synprot_error(int type, int code, uschar *data, uschar *errmess)
2462 log_write(type, LOG_MAIN, "SMTP %s error in \"%s\" %s %s",
2463 (type == L_smtp_syntax_error)? "syntax" : "protocol",
2464 string_printing(smtp_cmd_buffer), host_and_ident(TRUE), errmess);
2466 if (++synprot_error_count > smtp_max_synprot_errors)
2469 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
2470 "syntax or protocol errors (last command was \"%s\")",
2471 host_and_ident(FALSE), string_printing(smtp_cmd_buffer));
2476 smtp_printf("%d%c%s%s%s\r\n", code, (yield == 1)? '-' : ' ',
2477 (data == NULL)? US"" : data, (data == NULL)? US"" : US": ", errmess);
2479 smtp_printf("%d Too many syntax or protocol errors\r\n", code);
2488 /*************************************************
2489 * Log incomplete transactions *
2490 *************************************************/
2492 /* This function is called after a transaction has been aborted by RSET, QUIT,
2493 connection drops or other errors. It logs the envelope information received
2494 so far in order to preserve address verification attempts.
2496 Argument: string to indicate what aborted the transaction
2501 incomplete_transaction_log(uschar *what)
2503 if (sender_address == NULL || /* No transaction in progress */
2504 !LOGGING(smtp_incomplete_transaction))
2507 /* Build list of recipients for logging */
2509 if (recipients_count > 0)
2512 raw_recipients = store_get(recipients_count * sizeof(uschar *));
2513 for (i = 0; i < recipients_count; i++)
2514 raw_recipients[i] = recipients_list[i].address;
2515 raw_recipients_count = recipients_count;
2518 log_write(L_smtp_incomplete_transaction, LOG_MAIN|LOG_SENDER|LOG_RECIPIENTS,
2519 "%s incomplete transaction (%s)", host_and_ident(TRUE), what);
2525 /*************************************************
2526 * Send SMTP response, possibly multiline *
2527 *************************************************/
2529 /* There are, it seems, broken clients out there that cannot handle multiline
2530 responses. If no_multiline_responses is TRUE (it can be set from an ACL), we
2531 output nothing for non-final calls, and only the first line for anything else.
2534 code SMTP code, may involve extended status codes
2535 codelen length of smtp code; if > 4 there's an ESC
2536 final FALSE if the last line isn't the final line
2537 msg message text, possibly containing newlines
2543 smtp_respond(uschar* code, int codelen, BOOL final, uschar *msg)
2548 if (!final && no_multiline_responses) return;
2553 esclen = codelen - 4;
2556 /* If this is the first output for a (non-batch) RCPT command, see if all RCPTs
2557 have had the same. Note: this code is also present in smtp_printf(). It would
2558 be tidier to have it only in one place, but when it was added, it was easier to
2559 do it that way, so as not to have to mess with the code for the RCPT command,
2560 which sometimes uses smtp_printf() and sometimes smtp_respond(). */
2562 if (rcpt_in_progress)
2564 if (rcpt_smtp_response == NULL)
2565 rcpt_smtp_response = string_copy(msg);
2566 else if (rcpt_smtp_response_same &&
2567 Ustrcmp(rcpt_smtp_response, msg) != 0)
2568 rcpt_smtp_response_same = FALSE;
2569 rcpt_in_progress = FALSE;
2572 /* Not output the message, splitting it up into multiple lines if necessary. */
2576 uschar *nl = Ustrchr(msg, '\n');
2579 smtp_printf("%.3s%c%.*s%s\r\n", code, final? ' ':'-', esclen, esc, msg);
2582 else if (nl[1] == 0 || no_multiline_responses)
2584 smtp_printf("%.3s%c%.*s%.*s\r\n", code, final? ' ':'-', esclen, esc,
2585 (int)(nl - msg), msg);
2590 smtp_printf("%.3s-%.*s%.*s\r\n", code, esclen, esc, (int)(nl - msg), msg);
2592 while (isspace(*msg)) msg++;
2600 /*************************************************
2601 * Parse user SMTP message *
2602 *************************************************/
2604 /* This function allows for user messages overriding the response code details
2605 by providing a suitable response code string at the start of the message
2606 user_msg. Check the message for starting with a response code and optionally an
2607 extended status code. If found, check that the first digit is valid, and if so,
2608 change the code pointer and length to use the replacement. An invalid code
2609 causes a panic log; in this case, if the log messages is the same as the user
2610 message, we must also adjust the value of the log message to show the code that
2611 is actually going to be used (the original one).
2613 This function is global because it is called from receive.c as well as within
2616 Note that the code length returned includes the terminating whitespace
2617 character, which is always included in the regex match.
2620 code SMTP code, may involve extended status codes
2621 codelen length of smtp code; if > 4 there's an ESC
2623 log_msg optional log message, to be adjusted with the new SMTP code
2624 check_valid if true, verify the response code
2630 smtp_message_code(uschar **code, int *codelen, uschar **msg, uschar **log_msg,
2636 if (!msg || !*msg) return;
2638 if ((n = pcre_exec(regex_smtp_code, NULL, CS *msg, Ustrlen(*msg), 0,
2639 PCRE_EOPT, ovector, sizeof(ovector)/sizeof(int))) < 0) return;
2641 if (check_valid && (*msg)[0] != (*code)[0])
2643 log_write(0, LOG_MAIN|LOG_PANIC, "configured error code starts with "
2644 "incorrect digit (expected %c) in \"%s\"", (*code)[0], *msg);
2645 if (log_msg != NULL && *log_msg == *msg)
2646 *log_msg = string_sprintf("%s %s", *code, *log_msg + ovector[1]);
2651 *codelen = ovector[1]; /* Includes final space */
2653 *msg += ovector[1]; /* Chop the code off the message */
2660 /*************************************************
2661 * Handle an ACL failure *
2662 *************************************************/
2664 /* This function is called when acl_check() fails. As well as calls from within
2665 this module, it is called from receive.c for an ACL after DATA. It sorts out
2666 logging the incident, and sets up the error response. A message containing
2667 newlines is turned into a multiline SMTP response, but for logging, only the
2670 There's a table of default permanent failure response codes to use in
2671 globals.c, along with the table of names. VFRY is special. Despite RFC1123 it
2672 defaults disabled in Exim. However, discussion in connection with RFC 821bis
2673 (aka RFC 2821) has concluded that the response should be 252 in the disabled
2674 state, because there are broken clients that try VRFY before RCPT. A 5xx
2675 response should be given only when the address is positively known to be
2676 undeliverable. Sigh. We return 252 if there is no VRFY ACL or it provides
2677 no explicit code, but if there is one we let it know best.
2678 Also, for ETRN, 458 is given on refusal, and for AUTH, 503.
2680 From Exim 4.63, it is possible to override the response code details by
2681 providing a suitable response code string at the start of the message provided
2682 in user_msg. The code's first digit is checked for validity.
2685 where where the ACL was called from
2687 user_msg a message that can be included in an SMTP response
2688 log_msg a message for logging
2690 Returns: 0 in most cases
2691 2 if the failure code was FAIL_DROP, in which case the
2692 SMTP connection should be dropped (this value fits with the
2693 "done" variable in smtp_setup_msg() below)
2697 smtp_handle_acl_fail(int where, int rc, uschar *user_msg, uschar *log_msg)
2699 BOOL drop = rc == FAIL_DROP;
2703 uschar *sender_info = US"";
2705 #ifdef WITH_CONTENT_SCAN
2706 (where == ACL_WHERE_MIME)? US"during MIME ACL checks" :
2708 (where == ACL_WHERE_PREDATA)? US"DATA" :
2709 (where == ACL_WHERE_DATA)? US"after DATA" :
2710 #ifndef DISABLE_PRDR
2711 (where == ACL_WHERE_PRDR)? US"after DATA PRDR" :
2713 (smtp_cmd_data == NULL)?
2714 string_sprintf("%s in \"connect\" ACL", acl_wherenames[where]) :
2715 string_sprintf("%s %s", acl_wherenames[where], smtp_cmd_data);
2717 if (drop) rc = FAIL;
2719 /* Set the default SMTP code, and allow a user message to change it. */
2721 smtp_code = rc == FAIL ? acl_wherecodes[where] : US"451";
2722 smtp_message_code(&smtp_code, &codelen, &user_msg, &log_msg,
2723 where != ACL_WHERE_VRFY);
2725 /* We used to have sender_address here; however, there was a bug that was not
2726 updating sender_address after a rewrite during a verify. When this bug was
2727 fixed, sender_address at this point became the rewritten address. I'm not sure
2728 this is what should be logged, so I've changed to logging the unrewritten
2729 address to retain backward compatibility. */
2731 #ifndef WITH_CONTENT_SCAN
2732 if (where == ACL_WHERE_RCPT || where == ACL_WHERE_DATA)
2734 if (where == ACL_WHERE_RCPT || where == ACL_WHERE_DATA || where == ACL_WHERE_MIME)
2737 sender_info = string_sprintf("F=<%s>%s%s%s%s ",
2738 sender_address_unrewritten ? sender_address_unrewritten : sender_address,
2739 sender_host_authenticated ? US" A=" : US"",
2740 sender_host_authenticated ? sender_host_authenticated : US"",
2741 sender_host_authenticated && authenticated_id ? US":" : US"",
2742 sender_host_authenticated && authenticated_id ? authenticated_id : US""
2746 /* If there's been a sender verification failure with a specific message, and
2747 we have not sent a response about it yet, do so now, as a preliminary line for
2748 failures, but not defers. However, always log it for defer, and log it for fail
2749 unless the sender_verify_fail log selector has been turned off. */
2751 if (sender_verified_failed != NULL &&
2752 !testflag(sender_verified_failed, af_sverify_told))
2754 BOOL save_rcpt_in_progress = rcpt_in_progress;
2755 rcpt_in_progress = FALSE; /* So as not to treat these as the error */
2757 setflag(sender_verified_failed, af_sverify_told);
2759 if (rc != FAIL || LOGGING(sender_verify_fail))
2760 log_write(0, LOG_MAIN|LOG_REJECT, "%s sender verify %s for <%s>%s",
2761 host_and_ident(TRUE),
2762 ((sender_verified_failed->special_action & 255) == DEFER)? "defer":"fail",
2763 sender_verified_failed->address,
2764 (sender_verified_failed->message == NULL)? US"" :
2765 string_sprintf(": %s", sender_verified_failed->message));
2767 if (rc == FAIL && sender_verified_failed->user_message != NULL)
2768 smtp_respond(smtp_code, codelen, FALSE, string_sprintf(
2769 testflag(sender_verified_failed, af_verify_pmfail)?
2770 "Postmaster verification failed while checking <%s>\n%s\n"
2771 "Several RFCs state that you are required to have a postmaster\n"
2772 "mailbox for each mail domain. This host does not accept mail\n"
2773 "from domains whose servers reject the postmaster address."
2775 testflag(sender_verified_failed, af_verify_nsfail)?
2776 "Callback setup failed while verifying <%s>\n%s\n"
2777 "The initial connection, or a HELO or MAIL FROM:<> command was\n"
2778 "rejected. Refusing MAIL FROM:<> does not help fight spam, disregards\n"
2779 "RFC requirements, and stops you from receiving standard bounce\n"
2780 "messages. This host does not accept mail from domains whose servers\n"
2783 "Verification failed for <%s>\n%s",
2784 sender_verified_failed->address,
2785 sender_verified_failed->user_message));
2787 rcpt_in_progress = save_rcpt_in_progress;
2790 /* Sort out text for logging */
2792 log_msg = (log_msg == NULL)? US"" : string_sprintf(": %s", log_msg);
2793 lognl = Ustrchr(log_msg, '\n');
2794 if (lognl != NULL) *lognl = 0;
2796 /* Send permanent failure response to the command, but the code used isn't
2797 always a 5xx one - see comments at the start of this function. If the original
2798 rc was FAIL_DROP we drop the connection and yield 2. */
2800 if (rc == FAIL) smtp_respond(smtp_code, codelen, TRUE, (user_msg == NULL)?
2801 US"Administrative prohibition" : user_msg);
2803 /* Send temporary failure response to the command. Don't give any details,
2804 unless acl_temp_details is set. This is TRUE for a callout defer, a "defer"
2805 verb, and for a header verify when smtp_return_error_details is set.
2807 This conditional logic is all somewhat of a mess because of the odd
2808 interactions between temp_details and return_error_details. One day it should
2809 be re-implemented in a tidier fashion. */
2813 if (acl_temp_details && user_msg != NULL)
2815 if (smtp_return_error_details &&
2816 sender_verified_failed != NULL &&
2817 sender_verified_failed->message != NULL)
2819 smtp_respond(smtp_code, codelen, FALSE, sender_verified_failed->message);
2821 smtp_respond(smtp_code, codelen, TRUE, user_msg);
2824 smtp_respond(smtp_code, codelen, TRUE,
2825 US"Temporary local problem - please try later");
2828 /* Log the incident to the logs that are specified by log_reject_target
2829 (default main, reject). This can be empty to suppress logging of rejections. If
2830 the connection is not forcibly to be dropped, return 0. Otherwise, log why it
2831 is closing if required and return 2. */
2833 if (log_reject_target != 0)
2836 uschar * tls = s_tlslog(NULL, NULL, NULL);
2837 if (!tls) tls = US"";
2839 uschar * tls = US"";
2841 log_write(0, log_reject_target, "%s%s%s %s%srejected %s%s",
2842 LOGGING(dnssec) && sender_host_dnssec ? US" DS" : US"",
2843 host_and_ident(TRUE),
2846 rc == FAIL ? US"" : US"temporarily ",
2850 if (!drop) return 0;
2852 log_write(L_smtp_connection, LOG_MAIN, "%s closed by DROP in ACL",
2853 smtp_get_connection_info());
2855 /* Run the not-quit ACL, but without any custom messages. This should not be a
2856 problem, because we get here only if some other ACL has issued "drop", and
2857 in that case, *its* custom messages will have been used above. */
2859 smtp_notquit_exit(US"acl-drop", NULL, NULL);
2866 /*************************************************
2867 * Handle SMTP exit when QUIT is not given *
2868 *************************************************/
2870 /* This function provides a logging/statistics hook for when an SMTP connection
2871 is dropped on the floor or the other end goes away. It's a global function
2872 because it's called from receive.c as well as this module. As well as running
2873 the NOTQUIT ACL, if there is one, this function also outputs a final SMTP
2874 response, either with a custom message from the ACL, or using a default. There
2875 is one case, however, when no message is output - after "drop". In that case,
2876 the ACL that obeyed "drop" has already supplied the custom message, and NULL is
2877 passed to this function.
2879 In case things go wrong while processing this function, causing an error that
2880 may re-enter this funtion, there is a recursion check.
2883 reason What $smtp_notquit_reason will be set to in the ACL;
2884 if NULL, the ACL is not run
2885 code The error code to return as part of the response
2886 defaultrespond The default message if there's no user_msg
2892 smtp_notquit_exit(uschar *reason, uschar *code, uschar *defaultrespond, ...)
2895 uschar *user_msg = NULL;
2896 uschar *log_msg = NULL;
2898 /* Check for recursive acll */
2900 if (smtp_exit_function_called)
2902 log_write(0, LOG_PANIC, "smtp_notquit_exit() called more than once (%s)",
2906 smtp_exit_function_called = TRUE;
2908 /* Call the not-QUIT ACL, if there is one, unless no reason is given. */
2910 if (acl_smtp_notquit != NULL && reason != NULL)
2912 smtp_notquit_reason = reason;
2913 rc = acl_check(ACL_WHERE_NOTQUIT, NULL, acl_smtp_notquit, &user_msg,
2916 log_write(0, LOG_MAIN|LOG_PANIC, "ACL for not-QUIT returned ERROR: %s",
2920 /* Write an SMTP response if we are expected to give one. As the default
2921 responses are all internal, they should always fit in the buffer, but code a
2922 warning, just in case. Note that string_vformat() still leaves a complete
2923 string, even if it is incomplete. */
2925 if (code != NULL && defaultrespond != NULL)
2927 if (user_msg == NULL)
2931 va_start(ap, defaultrespond);
2932 if (!string_vformat(buffer, sizeof(buffer), CS defaultrespond, ap))
2933 log_write(0, LOG_MAIN|LOG_PANIC, "string too large in smtp_notquit_exit()");
2934 smtp_printf("%s %s\r\n", code, buffer);
2938 smtp_respond(code, 3, TRUE, user_msg);
2946 /*************************************************
2947 * Verify HELO argument *
2948 *************************************************/
2950 /* This function is called if helo_verify_hosts or helo_try_verify_hosts is
2951 matched. It is also called from ACL processing if verify = helo is used and
2952 verification was not previously tried (i.e. helo_try_verify_hosts was not
2953 matched). The result of its processing is to set helo_verified and
2954 helo_verify_failed. These variables should both be FALSE for this function to
2957 Note that EHLO/HELO is legitimately allowed to quote an address literal. Allow
2958 for IPv6 ::ffff: literals.
2961 Returns: TRUE if testing was completed;
2962 FALSE on a temporary failure
2966 smtp_verify_helo(void)
2970 HDEBUG(D_receive) debug_printf("verifying EHLO/HELO argument \"%s\"\n",
2973 if (sender_helo_name == NULL)
2975 HDEBUG(D_receive) debug_printf("no EHLO/HELO command was issued\n");
2978 /* Deal with the case of -bs without an IP address */
2980 else if (sender_host_address == NULL)
2982 HDEBUG(D_receive) debug_printf("no client IP address: assume success\n");
2983 helo_verified = TRUE;
2986 /* Deal with the more common case when there is a sending IP address */
2988 else if (sender_helo_name[0] == '[')
2990 helo_verified = Ustrncmp(sender_helo_name+1, sender_host_address,
2991 Ustrlen(sender_host_address)) == 0;
2996 if (strncmpic(sender_host_address, US"::ffff:", 7) == 0)
2997 helo_verified = Ustrncmp(sender_helo_name + 1,
2998 sender_host_address + 7, Ustrlen(sender_host_address) - 7) == 0;
3003 { if (helo_verified) debug_printf("matched host address\n"); }
3006 /* Do a reverse lookup if one hasn't already given a positive or negative
3007 response. If that fails, or the name doesn't match, try checking with a forward
3012 if (sender_host_name == NULL && !host_lookup_failed)
3013 yield = host_name_lookup() != DEFER;
3015 /* If a host name is known, check it and all its aliases. */
3017 if (sender_host_name)
3018 if ((helo_verified = strcmpic(sender_host_name, sender_helo_name) == 0))
3020 sender_helo_dnssec = sender_host_dnssec;
3021 HDEBUG(D_receive) debug_printf("matched host name\n");
3025 uschar **aliases = sender_host_aliases;
3027 if ((helo_verified = strcmpic(*aliases++, sender_helo_name) == 0))
3029 sender_helo_dnssec = sender_host_dnssec;
3033 HDEBUG(D_receive) if (helo_verified)
3034 debug_printf("matched alias %s\n", *(--aliases));
3037 /* Final attempt: try a forward lookup of the helo name */
3046 h.name = sender_helo_name;
3053 HDEBUG(D_receive) debug_printf("getting IP address for %s\n",
3055 rc = host_find_bydns(&h, NULL, HOST_FIND_BY_A,
3056 NULL, NULL, NULL, &d, NULL, NULL);
3057 if (rc == HOST_FOUND || rc == HOST_FOUND_LOCAL)
3058 for (hh = &h; hh; hh = hh->next)
3059 if (Ustrcmp(hh->address, sender_host_address) == 0)
3061 helo_verified = TRUE;
3062 if (h.dnssec == DS_YES) sender_helo_dnssec = TRUE;
3065 debug_printf("IP address for %s matches calling address\n"
3066 "Forward DNS security status: %sverified\n",
3067 sender_helo_name, sender_helo_dnssec ? "" : "un");
3074 if (!helo_verified) helo_verify_failed = TRUE; /* We've tried ... */
3081 /*************************************************
3082 * Send user response message *
3083 *************************************************/
3085 /* This function is passed a default response code and a user message. It calls
3086 smtp_message_code() to check and possibly modify the response code, and then
3087 calls smtp_respond() to transmit the response. I put this into a function
3088 just to avoid a lot of repetition.
3091 code the response code
3092 user_msg the user message
3098 smtp_user_msg(uschar *code, uschar *user_msg)
3101 smtp_message_code(&code, &len, &user_msg, NULL, TRUE);
3102 smtp_respond(code, len, TRUE, user_msg);
3108 smtp_in_auth(auth_instance *au, uschar ** s, uschar ** ss)
3110 const uschar *set_id = NULL;
3113 /* Run the checking code, passing the remainder of the command line as
3114 data. Initials the $auth<n> variables as empty. Initialize $0 empty and set
3115 it as the only set numerical variable. The authenticator may set $auth<n>
3116 and also set other numeric variables. The $auth<n> variables are preferred
3117 nowadays; the numerical variables remain for backwards compatibility.
3119 Afterwards, have a go at expanding the set_id string, even if
3120 authentication failed - for bad passwords it can be useful to log the
3121 userid. On success, require set_id to expand and exist, and put it in
3122 authenticated_id. Save this in permanent store, as the working store gets
3123 reset at HELO, RSET, etc. */
3125 for (i = 0; i < AUTH_VARS; i++) auth_vars[i] = NULL;
3127 expand_nlength[0] = 0; /* $0 contains nothing */
3129 rc = (au->info->servercode)(au, smtp_cmd_data);
3130 if (au->set_id) set_id = expand_string(au->set_id);
3131 expand_nmax = -1; /* Reset numeric variables */
3132 for (i = 0; i < AUTH_VARS; i++) auth_vars[i] = NULL; /* Reset $auth<n> */
3134 /* The value of authenticated_id is stored in the spool file and printed in
3135 log lines. It must not contain binary zeros or newline characters. In
3136 normal use, it never will, but when playing around or testing, this error
3137 can (did) happen. To guard against this, ensure that the id contains only
3138 printing characters. */
3140 if (set_id) set_id = string_printing(set_id);
3142 /* For the non-OK cases, set up additional logging data if set_id
3146 set_id = set_id && *set_id
3147 ? string_sprintf(" (set_id=%s)", set_id) : US"";
3149 /* Switch on the result */
3154 if (!au->set_id || set_id) /* Complete success */
3156 if (set_id) authenticated_id = string_copy_malloc(set_id);
3157 sender_host_authenticated = au->name;
3158 authentication_failed = FALSE;
3159 authenticated_fail_id = NULL; /* Impossible to already be set? */
3162 (sender_host_address ? protocols : protocols_local)
3163 [pextend + pauthed + (tls_in.active >= 0 ? pcrpted:0)];
3164 *s = *ss = US"235 Authentication succeeded";
3165 authenticated_by = au;
3169 /* Authentication succeeded, but we failed to expand the set_id string.
3170 Treat this as a temporary error. */
3172 auth_defer_msg = expand_string_message;
3176 if (set_id) authenticated_fail_id = string_copy_malloc(set_id);
3177 *s = string_sprintf("435 Unable to authenticate at present%s",
3178 auth_defer_user_msg);
3179 *ss = string_sprintf("435 Unable to authenticate at present%s: %s",
3180 set_id, auth_defer_msg);
3184 *s = *ss = US"501 Invalid base64 data";
3188 *s = *ss = US"501 Authentication cancelled";
3192 *s = *ss = US"553 Initial data not expected";
3196 if (set_id) authenticated_fail_id = string_copy_malloc(set_id);
3197 *s = US"535 Incorrect authentication data";
3198 *ss = string_sprintf("535 Incorrect authentication data%s", set_id);
3202 if (set_id) authenticated_fail_id = string_copy_malloc(set_id);
3203 *s = US"435 Internal error";
3204 *ss = string_sprintf("435 Internal error%s: return %d from authentication "
3205 "check", set_id, rc);
3217 qualify_recipient(uschar ** recipient, uschar * smtp_cmd_data, uschar * tag)
3220 if (allow_unqualified_recipient || strcmpic(*recipient, US"postmaster") == 0)
3222 DEBUG(D_receive) debug_printf("unqualified address %s accepted\n",
3224 rd = Ustrlen(recipient) + 1;
3225 *recipient = rewrite_address_qualify(*recipient, TRUE);
3228 smtp_printf("501 %s: recipient address must contain a domain\r\n",
3230 log_write(L_smtp_syntax_error,
3231 LOG_MAIN|LOG_REJECT, "unqualified %s rejected: <%s> %s%s",
3232 tag, *recipient, host_and_ident(TRUE), host_lookup_msg);
3239 /*************************************************
3240 * Initialize for SMTP incoming message *
3241 *************************************************/
3243 /* This function conducts the initial dialogue at the start of an incoming SMTP
3244 message, and builds a list of recipients. However, if the incoming message
3245 is part of a batch (-bS option) a separate function is called since it would
3246 be messy having tests splattered about all over this function. This function
3247 therefore handles the case where interaction is occurring. The input and output
3248 files are set up in smtp_in and smtp_out.
3250 The global recipients_list is set to point to a vector of recipient_item
3251 blocks, whose number is given by recipients_count. This is extended by the
3252 receive_add_recipient() function. The global variable sender_address is set to
3253 the sender's address. The yield is +1 if a message has been successfully
3254 started, 0 if a QUIT command was encountered or the connection was refused from
3255 the particular host, or -1 if the connection was lost.
3259 Returns: > 0 message successfully started (reached DATA)
3260 = 0 QUIT read or end of file reached or call refused
3265 smtp_setup_msg(void)
3268 BOOL toomany = FALSE;
3269 BOOL discarded = FALSE;
3270 BOOL last_was_rej_mail = FALSE;
3271 BOOL last_was_rcpt = FALSE;
3272 void *reset_point = store_get(0);
3274 DEBUG(D_receive) debug_printf("smtp_setup_msg entered\n");
3276 /* Reset for start of new message. We allow one RSET not to be counted as a
3277 nonmail command, for those MTAs that insist on sending it between every
3278 message. Ditto for EHLO/HELO and for STARTTLS, to allow for going in and out of
3279 TLS between messages (an Exim client may do this if it has messages queued up
3280 for the host). Note: we do NOT reset AUTH at this point. */
3282 smtp_reset(reset_point);
3283 message_ended = END_NOTSTARTED;
3285 cmd_list[CMD_LIST_RSET].is_mail_cmd = TRUE;
3286 cmd_list[CMD_LIST_HELO].is_mail_cmd = TRUE;
3287 cmd_list[CMD_LIST_EHLO].is_mail_cmd = TRUE;
3289 cmd_list[CMD_LIST_STARTTLS].is_mail_cmd = TRUE;
3290 cmd_list[CMD_LIST_TLS_AUTH].is_mail_cmd = TRUE;
3293 /* Set the local signal handler for SIGTERM - it tries to end off tidily */
3295 os_non_restarting_signal(SIGTERM, command_sigterm_handler);
3297 /* Batched SMTP is handled in a different function. */
3299 if (smtp_batched_input) return smtp_setup_batch_msg();
3301 /* Deal with SMTP commands. This loop is exited by setting done to a POSITIVE
3302 value. The values are 2 larger than the required yield of the function. */
3306 const uschar **argv;
3307 uschar *etrn_command;
3308 uschar *etrn_serialize_key;
3310 uschar *log_msg, *smtp_code;
3311 uschar *user_msg = NULL;
3312 uschar *recipient = NULL;
3313 uschar *hello = NULL;
3315 BOOL was_rej_mail = FALSE;
3316 BOOL was_rcpt = FALSE;
3317 void (*oldsignal)(int);
3319 int start, end, sender_domain, recipient_domain;
3323 uschar *orcpt = NULL;
3326 #if defined(SUPPORT_TLS) && defined(AUTH_TLS)
3327 /* Check once per STARTTLS or SSL-on-connect for a TLS AUTH */
3328 if ( tls_in.active >= 0
3330 && tls_in.certificate_verified
3331 && cmd_list[CMD_LIST_TLS_AUTH].is_mail_cmd
3334 cmd_list[CMD_LIST_TLS_AUTH].is_mail_cmd = FALSE;
3336 && (rc = acl_check(ACL_WHERE_AUTH, NULL, acl_smtp_auth,
3337 &user_msg, &log_msg)) != OK
3340 done = smtp_handle_acl_fail(ACL_WHERE_AUTH, rc, user_msg, log_msg);
3344 for (au = auths; au; au = au->next)
3345 if (strcmpic(US"tls", au->driver_name) == 0)
3347 smtp_cmd_data = NULL;
3349 if (smtp_in_auth(au, &s, &ss) == OK)
3350 { DEBUG(D_auth) debug_printf("tls auth succeeded\n"); }
3352 { DEBUG(D_auth) debug_printf("tls auth not succeeded\n"); }
3358 switch(smtp_read_command(TRUE))
3360 /* The AUTH command is not permitted to occur inside a transaction, and may
3361 occur successfully only once per connection. Actually, that isn't quite
3362 true. When TLS is started, all previous information about a connection must
3363 be discarded, so a new AUTH is permitted at that time.
3365 AUTH may only be used when it has been advertised. However, it seems that
3366 there are clients that send AUTH when it hasn't been advertised, some of
3367 them even doing this after HELO. And there are MTAs that accept this. Sigh.
3368 So there's a get-out that allows this to happen.
3370 AUTH is initially labelled as a "nonmail command" so that one occurrence
3371 doesn't get counted. We change the label here so that multiple failing
3372 AUTHS will eventually hit the nonmail threshold. */
3376 authentication_failed = TRUE;
3377 cmd_list[CMD_LIST_AUTH].is_mail_cmd = FALSE;
3379 if (!auth_advertised && !allow_auth_unadvertised)
3381 done = synprot_error(L_smtp_protocol_error, 503, NULL,
3382 US"AUTH command used when not advertised");
3385 if (sender_host_authenticated)
3387 done = synprot_error(L_smtp_protocol_error, 503, NULL,
3388 US"already authenticated");
3393 done = synprot_error(L_smtp_protocol_error, 503, NULL,
3394 US"not permitted in mail transaction");
3401 && (rc = acl_check(ACL_WHERE_AUTH, NULL, acl_smtp_auth,
3402 &user_msg, &log_msg)) != OK
3405 done = smtp_handle_acl_fail(ACL_WHERE_AUTH, rc, user_msg, log_msg);
3409 /* Find the name of the requested authentication mechanism. */
3412 while ((c = *smtp_cmd_data) != 0 && !isspace(c))
3414 if (!isalnum(c) && c != '-' && c != '_')
3416 done = synprot_error(L_smtp_syntax_error, 501, NULL,
3417 US"invalid character in authentication mechanism name");
3423 /* If not at the end of the line, we must be at white space. Terminate the
3424 name and move the pointer on to any data that may be present. */
3426 if (*smtp_cmd_data != 0)
3428 *smtp_cmd_data++ = 0;
3429 while (isspace(*smtp_cmd_data)) smtp_cmd_data++;
3432 /* Search for an authentication mechanism which is configured for use
3433 as a server and which has been advertised (unless, sigh, allow_auth_
3434 unadvertised is set). */
3436 for (au = auths; au; au = au->next)
3437 if (strcmpic(s, au->public_name) == 0 && au->server &&
3438 (au->advertised || allow_auth_unadvertised))
3443 c = smtp_in_auth(au, &s, &ss);
3445 smtp_printf("%s\r\n", s);
3447 log_write(0, LOG_MAIN|LOG_REJECT, "%s authenticator failed for %s: %s",
3448 au->name, host_and_ident(FALSE), ss);
3451 done = synprot_error(L_smtp_protocol_error, 504, NULL,
3452 string_sprintf("%s authentication mechanism not supported", s));
3454 break; /* AUTH_CMD */
3456 /* The HELO/EHLO commands are permitted to appear in the middle of a
3457 session as well as at the beginning. They have the effect of a reset in
3458 addition to their other functions. Their absence at the start cannot be
3459 taken to be an error.
3463 If the EHLO command is not acceptable to the SMTP server, 501, 500,
3464 or 502 failure replies MUST be returned as appropriate. The SMTP
3465 server MUST stay in the same state after transmitting these replies
3466 that it was in before the EHLO was received.
3468 Therefore, we do not do the reset until after checking the command for
3469 acceptability. This change was made for Exim release 4.11. Previously
3470 it did the reset first. */
3483 HELO_EHLO: /* Common code for HELO and EHLO */
3484 cmd_list[CMD_LIST_HELO].is_mail_cmd = FALSE;
3485 cmd_list[CMD_LIST_EHLO].is_mail_cmd = FALSE;
3487 /* Reject the HELO if its argument was invalid or non-existent. A
3488 successful check causes the argument to be saved in malloc store. */
3490 if (!check_helo(smtp_cmd_data))
3492 smtp_printf("501 Syntactically invalid %s argument(s)\r\n", hello);
3494 log_write(0, LOG_MAIN|LOG_REJECT, "rejected %s from %s: syntactically "
3495 "invalid argument(s): %s", hello, host_and_ident(FALSE),
3496 (*smtp_cmd_argument == 0)? US"(no argument given)" :
3497 string_printing(smtp_cmd_argument));
3499 if (++synprot_error_count > smtp_max_synprot_errors)
3501 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
3502 "syntax or protocol errors (last command was \"%s\")",
3503 host_and_ident(FALSE), string_printing(smtp_cmd_buffer));
3510 /* If sender_host_unknown is true, we have got here via the -bs interface,
3511 not called from inetd. Otherwise, we are running an IP connection and the
3512 host address will be set. If the helo name is the primary name of this
3513 host and we haven't done a reverse lookup, force one now. If helo_required
3514 is set, ensure that the HELO name matches the actual host. If helo_verify
3515 is set, do the same check, but softly. */
3517 if (!sender_host_unknown)
3519 BOOL old_helo_verified = helo_verified;
3520 uschar *p = smtp_cmd_data;
3522 while (*p != 0 && !isspace(*p)) { *p = tolower(*p); p++; }
3525 /* Force a reverse lookup if HELO quoted something in helo_lookup_domains
3526 because otherwise the log can be confusing. */
3528 if (sender_host_name == NULL &&
3529 (deliver_domain = sender_helo_name, /* set $domain */
3530 match_isinlist(sender_helo_name, CUSS &helo_lookup_domains, 0,
3531 &domainlist_anchor, NULL, MCL_DOMAIN, TRUE, NULL)) == OK)
3532 (void)host_name_lookup();
3534 /* Rebuild the fullhost info to include the HELO name (and the real name
3535 if it was looked up.) */
3537 host_build_sender_fullhost(); /* Rebuild */
3538 set_process_info("handling%s incoming connection from %s",
3539 (tls_in.active >= 0)? " TLS" : "", host_and_ident(FALSE));
3541 /* Verify if configured. This doesn't give much security, but it does
3542 make some people happy to be able to do it. If helo_required is set,
3543 (host matches helo_verify_hosts) failure forces rejection. If helo_verify
3544 is set (host matches helo_try_verify_hosts), it does not. This is perhaps
3545 now obsolescent, since the verification can now be requested selectively
3548 helo_verified = helo_verify_failed = sender_helo_dnssec = FALSE;
3549 if (helo_required || helo_verify)
3551 BOOL tempfail = !smtp_verify_helo();
3556 smtp_printf("%d %s argument does not match calling host\r\n",
3557 tempfail? 451 : 550, hello);
3558 log_write(0, LOG_MAIN|LOG_REJECT, "%srejected \"%s %s\" from %s",
3559 tempfail? "temporarily " : "",
3560 hello, sender_helo_name, host_and_ident(FALSE));
3561 helo_verified = old_helo_verified;
3562 break; /* End of HELO/EHLO processing */
3564 HDEBUG(D_all) debug_printf("%s verification failed but host is in "
3565 "helo_try_verify_hosts\n", hello);
3570 #ifdef EXPERIMENTAL_SPF
3571 /* set up SPF context */
3572 spf_init(sender_helo_name, sender_host_address);
3575 /* Apply an ACL check if one is defined; afterwards, recheck
3576 synchronization in case the client started sending in a delay. */
3579 if ((rc = acl_check(ACL_WHERE_HELO, NULL, acl_smtp_helo,
3580 &user_msg, &log_msg)) != OK)
3582 done = smtp_handle_acl_fail(ACL_WHERE_HELO, rc, user_msg, log_msg);
3583 sender_helo_name = NULL;
3584 host_build_sender_fullhost(); /* Rebuild */
3587 else if (!check_sync()) goto SYNC_FAILURE;
3589 /* Generate an OK reply. The default string includes the ident if present,
3590 and also the IP address if present. Reflecting back the ident is intended
3591 as a deterrent to mail forgers. For maximum efficiency, and also because
3592 some broken systems expect each response to be in a single packet, arrange
3593 that the entire reply is sent in one write(). */
3595 auth_advertised = FALSE;
3596 pipelining_advertised = FALSE;
3598 tls_advertised = FALSE;
3600 dsn_advertised = FALSE;
3602 smtputf8_advertised = FALSE;
3605 smtp_code = US"250 "; /* Default response code plus space*/
3606 if (user_msg == NULL)
3608 s = string_sprintf("%.3s %s Hello %s%s%s",
3610 smtp_active_hostname,
3611 (sender_ident == NULL)? US"" : sender_ident,
3612 (sender_ident == NULL)? US"" : US" at ",
3613 (sender_host_name == NULL)? sender_helo_name : sender_host_name);
3618 if (sender_host_address != NULL)
3620 s = string_catn(s, &size, &ptr, US" [", 2);
3621 s = string_cat (s, &size, &ptr, sender_host_address);
3622 s = string_catn(s, &size, &ptr, US"]", 1);
3626 /* A user-supplied EHLO greeting may not contain more than one line. Note
3627 that the code returned by smtp_message_code() includes the terminating
3628 whitespace character. */
3634 smtp_message_code(&smtp_code, &codelen, &user_msg, NULL, TRUE);
3635 s = string_sprintf("%.*s%s", codelen, smtp_code, user_msg);
3636 if ((ss = strpbrk(CS s, "\r\n")) != NULL)
3638 log_write(0, LOG_MAIN|LOG_PANIC, "EHLO/HELO response must not contain "
3639 "newlines: message truncated: %s", string_printing(s));
3646 s = string_catn(s, &size, &ptr, US"\r\n", 2);
3648 /* If we received EHLO, we must create a multiline response which includes
3649 the functions supported. */
3655 /* I'm not entirely happy with this, as an MTA is supposed to check
3656 that it has enough room to accept a message of maximum size before
3657 it sends this. However, there seems little point in not sending it.
3658 The actual size check happens later at MAIL FROM time. By postponing it
3659 till then, VRFY and EXPN can be used after EHLO when space is short. */
3661 if (thismessage_size_limit > 0)
3663 sprintf(CS big_buffer, "%.3s-SIZE %d\r\n", smtp_code,
3664 thismessage_size_limit);
3665 s = string_cat(s, &size, &ptr, big_buffer);
3669 s = string_catn(s, &size, &ptr, smtp_code, 3);
3670 s = string_catn(s, &size, &ptr, US"-SIZE\r\n", 7);
3673 /* Exim does not do protocol conversion or data conversion. It is 8-bit
3674 clean; if it has an 8-bit character in its hand, it just sends it. It
3675 cannot therefore specify 8BITMIME and remain consistent with the RFCs.
3676 However, some users want this option simply in order to stop MUAs
3677 mangling messages that contain top-bit-set characters. It is therefore
3678 provided as an option. */
3680 if (accept_8bitmime)
3682 s = string_catn(s, &size, &ptr, smtp_code, 3);
3683 s = string_catn(s, &size, &ptr, US"-8BITMIME\r\n", 11);
3686 /* Advertise DSN support if configured to do so. */
3687 if (verify_check_host(&dsn_advertise_hosts) != FAIL)
3689 s = string_catn(s, &size, &ptr, smtp_code, 3);
3690 s = string_catn(s, &size, &ptr, US"-DSN\r\n", 6);
3691 dsn_advertised = TRUE;
3694 /* Advertise ETRN if there's an ACL checking whether a host is
3695 permitted to issue it; a check is made when any host actually tries. */
3697 if (acl_smtp_etrn != NULL)
3699 s = string_catn(s, &size, &ptr, smtp_code, 3);
3700 s = string_catn(s, &size, &ptr, US"-ETRN\r\n", 7);
3703 /* Advertise EXPN if there's an ACL checking whether a host is
3704 permitted to issue it; a check is made when any host actually tries. */
3706 if (acl_smtp_expn != NULL)
3708 s = string_catn(s, &size, &ptr, smtp_code, 3);
3709 s = string_catn(s, &size, &ptr, US"-EXPN\r\n", 7);
3712 /* Exim is quite happy with pipelining, so let the other end know that
3713 it is safe to use it, unless advertising is disabled. */
3715 if (pipelining_enable &&
3716 verify_check_host(&pipelining_advertise_hosts) == OK)
3718 s = string_catn(s, &size, &ptr, smtp_code, 3);
3719 s = string_catn(s, &size, &ptr, US"-PIPELINING\r\n", 13);
3720 sync_cmd_limit = NON_SYNC_CMD_PIPELINING;
3721 pipelining_advertised = TRUE;
3725 /* If any server authentication mechanisms are configured, advertise
3726 them if the current host is in auth_advertise_hosts. The problem with
3727 advertising always is that some clients then require users to
3728 authenticate (and aren't configurable otherwise) even though it may not
3729 be necessary (e.g. if the host is in host_accept_relay).
3731 RFC 2222 states that SASL mechanism names contain only upper case
3732 letters, so output the names in upper case, though we actually recognize
3733 them in either case in the AUTH command. */
3736 #if defined(SUPPORT_TLS) && defined(AUTH_TLS)
3737 && !sender_host_authenticated
3739 && verify_check_host(&auth_advertise_hosts) == OK
3744 for (au = auths; au; au = au->next)
3745 if (au->server && (au->advertise_condition == NULL ||
3746 expand_check_condition(au->advertise_condition, au->name,
3747 US"authenticator")))
3752 s = string_catn(s, &size, &ptr, smtp_code, 3);
3753 s = string_catn(s, &size, &ptr, US"-AUTH", 5);
3755 auth_advertised = TRUE;
3758 s = string_catn(s, &size, &ptr, US" ", 1);
3759 s = string_cat (s, &size, &ptr, au->public_name);
3760 while (++saveptr < ptr) s[saveptr] = toupper(s[saveptr]);
3761 au->advertised = TRUE;
3764 au->advertised = FALSE;
3766 if (!first) s = string_catn(s, &size, &ptr, US"\r\n", 2);
3769 /* Advertise TLS (Transport Level Security) aka SSL (Secure Socket Layer)
3770 if it has been included in the binary, and the host matches
3771 tls_advertise_hosts. We must *not* advertise if we are already in a
3772 secure connection. */
3774 if (verify_check_host(&chunking_advertise_hosts) != FAIL)
3776 s = string_catn(s, &size, &ptr, smtp_code, 3);
3777 s = string_catn(s, &size, &ptr, US"-CHUNKING\r\n", 11);
3781 if (tls_in.active < 0 &&
3782 verify_check_host(&tls_advertise_hosts) != FAIL)
3784 s = string_catn(s, &size, &ptr, smtp_code, 3);
3785 s = string_catn(s, &size, &ptr, US"-STARTTLS\r\n", 11);
3786 tls_advertised = TRUE;
3790 #ifndef DISABLE_PRDR
3791 /* Per Recipient Data Response, draft by Eric A. Hall extending RFC */
3794 s = string_catn(s, &size, &ptr, smtp_code, 3);
3795 s = string_catn(s, &size, &ptr, US"-PRDR\r\n", 7);
3800 if ( accept_8bitmime
3801 && verify_check_host(&smtputf8_advertise_hosts) != FAIL)
3803 s = string_catn(s, &size, &ptr, smtp_code, 3);
3804 s = string_catn(s, &size, &ptr, US"-SMTPUTF8\r\n", 11);
3805 smtputf8_advertised = TRUE;
3809 /* Finish off the multiline reply with one that is always available. */
3811 s = string_catn(s, &size, &ptr, smtp_code, 3);
3812 s = string_catn(s, &size, &ptr, US" HELP\r\n", 7);
3815 /* Terminate the string (for debug), write it, and note that HELO/EHLO
3821 if (tls_in.active >= 0) (void)tls_write(TRUE, s, ptr); else
3825 int i = fwrite(s, 1, ptr, smtp_out); i = i; /* compiler quietening */
3830 while ((cr = Ustrchr(s, '\r')) != NULL) /* lose CRs */
3831 memmove(cr, cr + 1, (ptr--) - (cr - s));
3832 debug_printf("SMTP>> %s", s);
3836 /* Reset the protocol and the state, abandoning any previous message. */
3838 (sender_host_address ? protocols : protocols_local)
3840 ? pextend + (sender_host_authenticated ? pauthed : 0)
3842 + (tls_in.active >= 0 ? pcrpted : 0)
3844 smtp_reset(reset_point);
3846 break; /* HELO/EHLO */
3849 /* The MAIL command requires an address as an operand. All we do
3850 here is to parse it for syntactic correctness. The form "<>" is
3851 a special case which converts into an empty string. The start/end
3852 pointers in the original are not used further for this address, as
3853 it is the canonical extracted address which is all that is kept. */
3857 smtp_mailcmd_count++; /* Count for limit and ratelimit */
3858 was_rej_mail = TRUE; /* Reset if accepted */
3859 env_mail_type_t * mail_args; /* Sanity check & validate args */
3861 if (helo_required && !helo_seen)
3863 smtp_printf("503 HELO or EHLO required\r\n");
3864 log_write(0, LOG_MAIN|LOG_REJECT, "rejected MAIL from %s: no "
3865 "HELO/EHLO given", host_and_ident(FALSE));
3869 if (sender_address != NULL)
3871 done = synprot_error(L_smtp_protocol_error, 503, NULL,
3872 US"sender already given");
3876 if (smtp_cmd_data[0] == 0)
3878 done = synprot_error(L_smtp_protocol_error, 501, NULL,
3879 US"MAIL must have an address operand");
3883 /* Check to see if the limit for messages per connection would be
3884 exceeded by accepting further messages. */
3886 if (smtp_accept_max_per_connection > 0 &&
3887 smtp_mailcmd_count > smtp_accept_max_per_connection)
3889 smtp_printf("421 too many messages in this connection\r\n");
3890 log_write(0, LOG_MAIN|LOG_REJECT, "rejected MAIL command %s: too many "
3891 "messages in one connection", host_and_ident(TRUE));
3895 /* Reset for start of message - even if this is going to fail, we
3896 obviously need to throw away any previous data. */
3898 smtp_reset(reset_point);
3900 sender_data = recipient_data = NULL;
3902 /* Loop, checking for ESMTP additions to the MAIL FROM command. */
3906 uschar *name, *value, *end;
3907 unsigned long int size;
3908 BOOL arg_error = FALSE;
3910 if (!extract_option(&name, &value)) break;
3912 for (mail_args = env_mail_type_list;
3913 mail_args->value != ENV_MAIL_OPT_NULL;
3916 if (strcmpic(name, mail_args->name) == 0)
3918 if (mail_args->need_value && strcmpic(value, US"") == 0)
3921 switch(mail_args->value)
3923 /* Handle SIZE= by reading the value. We don't do the check till later,
3924 in order to be able to log the sender address on failure. */
3925 case ENV_MAIL_OPT_SIZE:
3926 if (((size = Ustrtoul(value, &end, 10)), *end == 0))
3928 if ((size == ULONG_MAX && errno == ERANGE) || size > INT_MAX)
3930 message_size = (int)size;
3936 /* If this session was initiated with EHLO and accept_8bitmime is set,
3937 Exim will have indicated that it supports the BODY=8BITMIME option. In
3938 fact, it does not support this according to the RFCs, in that it does not
3939 take any special action for forwarding messages containing 8-bit
3940 characters. That is why accept_8bitmime is not the default setting, but
3941 some sites want the action that is provided. We recognize both "8BITMIME"
3942 and "7BIT" as body types, but take no action. */
3943 case ENV_MAIL_OPT_BODY:
3944 if (accept_8bitmime) {
3945 if (strcmpic(value, US"8BITMIME") == 0)
3947 else if (strcmpic(value, US"7BIT") == 0)
3952 done = synprot_error(L_smtp_syntax_error, 501, NULL,
3953 US"invalid data for BODY");
3956 DEBUG(D_receive) debug_printf("8BITMIME: %d\n", body_8bitmime);
3962 /* Handle the two DSN options, but only if configured to do so (which
3963 will have caused "DSN" to be given in the EHLO response). The code itself
3964 is included only if configured in at build time. */
3966 case ENV_MAIL_OPT_RET:
3969 /* Check if RET has already been set */
3972 synprot_error(L_smtp_syntax_error, 501, NULL,
3973 US"RET can be specified once only");
3976 dsn_ret = strcmpic(value, US"HDRS") == 0
3978 : strcmpic(value, US"FULL") == 0
3981 DEBUG(D_receive) debug_printf("DSN_RET: %d\n", dsn_ret);
3982 /* Check for invalid invalid value, and exit with error */
3985 synprot_error(L_smtp_syntax_error, 501, NULL,
3986 US"Value for RET is invalid");
3991 case ENV_MAIL_OPT_ENVID:
3994 /* Check if the dsn envid has been already set */
3995 if (dsn_envid != NULL)
3997 synprot_error(L_smtp_syntax_error, 501, NULL,
3998 US"ENVID can be specified once only");
4001 dsn_envid = string_copy(value);
4002 DEBUG(D_receive) debug_printf("DSN_ENVID: %s\n", dsn_envid);
4006 /* Handle the AUTH extension. If the value given is not "<>" and either
4007 the ACL says "yes" or there is no ACL but the sending host is
4008 authenticated, we set it up as the authenticated sender. However, if the
4009 authenticator set a condition to be tested, we ignore AUTH on MAIL unless
4010 the condition is met. The value of AUTH is an xtext, which means that +,
4011 = and cntrl chars are coded in hex; however "<>" is unaffected by this
4013 case ENV_MAIL_OPT_AUTH:
4014 if (Ustrcmp(value, "<>") != 0)
4019 if (auth_xtextdecode(value, &authenticated_sender) < 0)
4021 /* Put back terminator overrides for error message */
4024 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4025 US"invalid data for AUTH");
4028 if (acl_smtp_mailauth == NULL)
4030 ignore_msg = US"client not authenticated";
4031 rc = (sender_host_authenticated != NULL)? OK : FAIL;
4035 ignore_msg = US"rejected by ACL";
4036 rc = acl_check(ACL_WHERE_MAILAUTH, NULL, acl_smtp_mailauth,
4037 &user_msg, &log_msg);
4043 if (authenticated_by == NULL ||
4044 authenticated_by->mail_auth_condition == NULL ||
4045 expand_check_condition(authenticated_by->mail_auth_condition,
4046 authenticated_by->name, US"authenticator"))
4047 break; /* Accept the AUTH */
4049 ignore_msg = US"server_mail_auth_condition failed";
4050 if (authenticated_id != NULL)
4051 ignore_msg = string_sprintf("%s: authenticated ID=\"%s\"",
4052 ignore_msg, authenticated_id);
4057 authenticated_sender = NULL;
4058 log_write(0, LOG_MAIN, "ignoring AUTH=%s from %s (%s)",
4059 value, host_and_ident(TRUE), ignore_msg);
4062 /* Should only get DEFER or ERROR here. Put back terminator
4063 overrides for error message */
4068 (void)smtp_handle_acl_fail(ACL_WHERE_MAILAUTH, rc, user_msg,
4075 #ifndef DISABLE_PRDR
4076 case ENV_MAIL_OPT_PRDR:
4078 prdr_requested = TRUE;
4083 case ENV_MAIL_OPT_UTF8:
4084 if (smtputf8_advertised)
4086 DEBUG(D_receive) debug_printf("smtputf8 requested\n");
4087 message_smtputf8 = allow_utf8_domains = TRUE;
4088 received_protocol = string_sprintf("utf8%s", received_protocol);
4092 /* No valid option. Stick back the terminator characters and break
4093 the loop. Do the name-terminator second as extract_option sets
4094 value==name when it found no equal-sign.
4095 An error for a malformed address will occur. */
4096 case ENV_MAIL_OPT_NULL:
4104 /* Break out of for loop if switch() had bad argument or
4105 when start of the email address is reached */
4106 if (arg_error) break;
4109 /* If we have passed the threshold for rate limiting, apply the current
4110 delay, and update it for next time, provided this is a limited host. */
4112 if (smtp_mailcmd_count > smtp_rlm_threshold &&
4113 verify_check_host(&smtp_ratelimit_hosts) == OK)
4115 DEBUG(D_receive) debug_printf("rate limit MAIL: delay %.3g sec\n",
4116 smtp_delay_mail/1000.0);
4117 millisleep((int)smtp_delay_mail);
4118 smtp_delay_mail *= smtp_rlm_factor;
4119 if (smtp_delay_mail > (double)smtp_rlm_limit)
4120 smtp_delay_mail = (double)smtp_rlm_limit;
4123 /* Now extract the address, first applying any SMTP-time rewriting. The
4124 TRUE flag allows "<>" as a sender address. */
4126 raw_sender = rewrite_existflags & rewrite_smtp
4127 ? rewrite_one(smtp_cmd_data, rewrite_smtp, NULL, FALSE, US"",
4128 global_rewrite_rules)
4132 parse_extract_address(raw_sender, &errmess, &start, &end, &sender_domain,
4137 done = synprot_error(L_smtp_syntax_error, 501, smtp_cmd_data, errmess);
4141 sender_address = raw_sender;
4143 /* If there is a configured size limit for mail, check that this message
4144 doesn't exceed it. The check is postponed to this point so that the sender
4147 if (thismessage_size_limit > 0 && message_size > thismessage_size_limit)
4149 smtp_printf("552 Message size exceeds maximum permitted\r\n");
4150 log_write(L_size_reject,
4151 LOG_MAIN|LOG_REJECT, "rejected MAIL FROM:<%s> %s: "
4152 "message too big: size%s=%d max=%d",
4154 host_and_ident(TRUE),
4155 (message_size == INT_MAX)? ">" : "",
4157 thismessage_size_limit);
4158 sender_address = NULL;
4162 /* Check there is enough space on the disk unless configured not to.
4163 When smtp_check_spool_space is set, the check is for thismessage_size_limit
4164 plus the current message - i.e. we accept the message only if it won't
4165 reduce the space below the threshold. Add 5000 to the size to allow for
4166 overheads such as the Received: line and storing of recipients, etc.
4167 By putting the check here, even when SIZE is not given, it allow VRFY
4168 and EXPN etc. to be used when space is short. */
4170 if (!receive_check_fs(
4171 (smtp_check_spool_space && message_size >= 0)?
4172 message_size + 5000 : 0))
4174 smtp_printf("452 Space shortage, please try later\r\n");
4175 sender_address = NULL;
4179 /* If sender_address is unqualified, reject it, unless this is a locally
4180 generated message, or the sending host or net is permitted to send
4181 unqualified addresses - typically local machines behaving as MUAs -
4182 in which case just qualify the address. The flag is set above at the start
4183 of the SMTP connection. */
4185 if (sender_domain == 0 && sender_address[0] != 0)
4187 if (allow_unqualified_sender)
4189 sender_domain = Ustrlen(sender_address) + 1;
4190 sender_address = rewrite_address_qualify(sender_address, FALSE);
4191 DEBUG(D_receive) debug_printf("unqualified address %s accepted\n",
4196 smtp_printf("501 %s: sender address must contain a domain\r\n",
4198 log_write(L_smtp_syntax_error,
4199 LOG_MAIN|LOG_REJECT,
4200 "unqualified sender rejected: <%s> %s%s",
4202 host_and_ident(TRUE),
4204 sender_address = NULL;
4209 /* Apply an ACL check if one is defined, before responding. Afterwards,
4210 when pipelining is not advertised, do another sync check in case the ACL
4211 delayed and the client started sending in the meantime. */
4215 rc = acl_check(ACL_WHERE_MAIL, NULL, acl_smtp_mail, &user_msg, &log_msg);
4216 if (rc == OK && !pipelining_advertised && !check_sync())
4222 if (rc == OK || rc == DISCARD)
4225 smtp_printf("%s%s%s", US"250 OK",
4226 #ifndef DISABLE_PRDR
4227 prdr_requested ? US", PRDR Requested" : US"",
4234 #ifndef DISABLE_PRDR
4236 user_msg = string_sprintf("%s%s", user_msg, US", PRDR Requested");
4238 smtp_user_msg(US"250", user_msg);
4240 smtp_delay_rcpt = smtp_rlr_base;
4241 recipients_discarded = (rc == DISCARD);
4242 was_rej_mail = FALSE;
4246 done = smtp_handle_acl_fail(ACL_WHERE_MAIL, rc, user_msg, log_msg);
4247 sender_address = NULL;
4252 /* The RCPT command requires an address as an operand. There may be any
4253 number of RCPT commands, specifying multiple recipients. We build them all
4254 into a data structure. The start/end values given by parse_extract_address
4255 are not used, as we keep only the extracted address. */
4260 was_rcpt = rcpt_in_progress = TRUE;
4262 /* There must be a sender address; if the sender was rejected and
4263 pipelining was advertised, we assume the client was pipelining, and do not
4264 count this as a protocol error. Reset was_rej_mail so that further RCPTs
4265 get the same treatment. */
4267 if (sender_address == NULL)
4269 if (pipelining_advertised && last_was_rej_mail)
4271 smtp_printf("503 sender not yet given\r\n");
4272 was_rej_mail = TRUE;
4276 done = synprot_error(L_smtp_protocol_error, 503, NULL,
4277 US"sender not yet given");
4278 was_rcpt = FALSE; /* Not a valid RCPT */
4284 /* Check for an operand */
4286 if (smtp_cmd_data[0] == 0)
4288 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4289 US"RCPT must have an address operand");
4294 /* Set the DSN flags orcpt and dsn_flags from the session*/
4300 uschar *name, *value;
4302 if (!extract_option(&name, &value))
4305 if (dsn_advertised && strcmpic(name, US"ORCPT") == 0)
4307 /* Check whether orcpt has been already set */
4310 synprot_error(L_smtp_syntax_error, 501, NULL,
4311 US"ORCPT can be specified once only");
4314 orcpt = string_copy(value);
4315 DEBUG(D_receive) debug_printf("DSN orcpt: %s\n", orcpt);
4318 else if (dsn_advertised && strcmpic(name, US"NOTIFY") == 0)
4320 /* Check if the notify flags have been already set */
4323 synprot_error(L_smtp_syntax_error, 501, NULL,
4324 US"NOTIFY can be specified once only");
4327 if (strcmpic(value, US"NEVER") == 0)
4328 flags |= rf_notify_never;
4335 while (*pp != 0 && *pp != ',') pp++;
4336 if (*pp == ',') *pp++ = 0;
4337 if (strcmpic(p, US"SUCCESS") == 0)
4339 DEBUG(D_receive) debug_printf("DSN: Setting notify success\n");
4340 flags |= rf_notify_success;
4342 else if (strcmpic(p, US"FAILURE") == 0)
4344 DEBUG(D_receive) debug_printf("DSN: Setting notify failure\n");
4345 flags |= rf_notify_failure;
4347 else if (strcmpic(p, US"DELAY") == 0)
4349 DEBUG(D_receive) debug_printf("DSN: Setting notify delay\n");
4350 flags |= rf_notify_delay;
4354 /* Catch any strange values */
4355 synprot_error(L_smtp_syntax_error, 501, NULL,
4356 US"Invalid value for NOTIFY parameter");
4361 DEBUG(D_receive) debug_printf("DSN Flags: %x\n", flags);
4365 /* Unknown option. Stick back the terminator characters and break
4366 the loop. An error for a malformed address will occur. */
4370 DEBUG(D_receive) debug_printf("Invalid RCPT option: %s : %s\n", name, value);
4377 /* Apply SMTP rewriting then extract the working address. Don't allow "<>"
4378 as a recipient address */
4380 recipient = rewrite_existflags & rewrite_smtp
4381 ? rewrite_one(smtp_cmd_data, rewrite_smtp, NULL, FALSE, US"",
4382 global_rewrite_rules)
4385 if (!(recipient = parse_extract_address(recipient, &errmess, &start, &end,
4386 &recipient_domain, FALSE)))
4388 done = synprot_error(L_smtp_syntax_error, 501, smtp_cmd_data, errmess);
4393 /* If the recipient address is unqualified, reject it, unless this is a
4394 locally generated message. However, unqualified addresses are permitted
4395 from a configured list of hosts and nets - typically when behaving as
4396 MUAs rather than MTAs. Sad that SMTP is used for both types of traffic,
4397 really. The flag is set at the start of the SMTP connection.
4399 RFC 1123 talks about supporting "the reserved mailbox postmaster"; I always
4400 assumed this meant "reserved local part", but the revision of RFC 821 and
4401 friends now makes it absolutely clear that it means *mailbox*. Consequently
4402 we must always qualify this address, regardless. */
4404 if (recipient_domain == 0)
4405 if (!(recipient_domain = qualify_recipient(&recipient, smtp_cmd_data,
4412 /* Check maximum allowed */
4414 if (rcpt_count > recipients_max && recipients_max > 0)
4416 if (recipients_max_reject)
4419 smtp_printf("552 too many recipients\r\n");
4421 log_write(0, LOG_MAIN|LOG_REJECT, "too many recipients: message "
4422 "rejected: sender=<%s> %s", sender_address, host_and_ident(TRUE));
4427 smtp_printf("452 too many recipients\r\n");
4429 log_write(0, LOG_MAIN|LOG_REJECT, "too many recipients: excess "
4430 "temporarily rejected: sender=<%s> %s", sender_address,
4431 host_and_ident(TRUE));
4438 /* If we have passed the threshold for rate limiting, apply the current
4439 delay, and update it for next time, provided this is a limited host. */
4441 if (rcpt_count > smtp_rlr_threshold &&
4442 verify_check_host(&smtp_ratelimit_hosts) == OK)
4444 DEBUG(D_receive) debug_printf("rate limit RCPT: delay %.3g sec\n",
4445 smtp_delay_rcpt/1000.0);
4446 millisleep((int)smtp_delay_rcpt);
4447 smtp_delay_rcpt *= smtp_rlr_factor;
4448 if (smtp_delay_rcpt > (double)smtp_rlr_limit)
4449 smtp_delay_rcpt = (double)smtp_rlr_limit;
4452 /* If the MAIL ACL discarded all the recipients, we bypass ACL checking
4453 for them. Otherwise, check the access control list for this recipient. As
4454 there may be a delay in this, re-check for a synchronization error
4455 afterwards, unless pipelining was advertised. */
4457 if (recipients_discarded) rc = DISCARD; else
4459 rc = acl_check(ACL_WHERE_RCPT, recipient, acl_smtp_rcpt, &user_msg,
4461 if (rc == OK && !pipelining_advertised && !check_sync())
4465 /* The ACL was happy */
4469 if (user_msg == NULL) smtp_printf("250 Accepted\r\n");
4470 else smtp_user_msg(US"250", user_msg);
4471 receive_add_recipient(recipient, -1);
4473 /* Set the dsn flags in the recipients_list */
4474 recipients_list[recipients_count-1].orcpt = orcpt;
4475 recipients_list[recipients_count-1].dsn_flags = flags;
4477 DEBUG(D_receive) debug_printf("DSN: orcpt: %s flags: %d\n",
4478 recipients_list[recipients_count-1].orcpt,
4479 recipients_list[recipients_count-1].dsn_flags);
4482 /* The recipient was discarded */
4484 else if (rc == DISCARD)
4486 if (user_msg == NULL) smtp_printf("250 Accepted\r\n");
4487 else smtp_user_msg(US"250", user_msg);
4490 log_write(0, LOG_MAIN|LOG_REJECT, "%s F=<%s> RCPT %s: "
4491 "discarded by %s ACL%s%s", host_and_ident(TRUE),
4492 sender_address_unrewritten? sender_address_unrewritten : sender_address,
4493 smtp_cmd_argument, recipients_discarded? "MAIL" : "RCPT",
4494 log_msg ? US": " : US"", log_msg ? log_msg : US"");
4497 /* Either the ACL failed the address, or it was deferred. */
4501 if (rc == FAIL) rcpt_fail_count++; else rcpt_defer_count++;
4502 done = smtp_handle_acl_fail(ACL_WHERE_RCPT, rc, user_msg, log_msg);
4507 /* The DATA command is legal only if it follows successful MAIL FROM
4508 and RCPT TO commands. However, if pipelining is advertised, a bad DATA is
4509 not counted as a protocol error if it follows RCPT (which must have been
4510 rejected if there are no recipients.) This function is complete when a
4511 valid DATA command is encountered.
4513 Note concerning the code used: RFC 2821 says this:
4515 - If there was no MAIL, or no RCPT, command, or all such commands
4516 were rejected, the server MAY return a "command out of sequence"
4517 (503) or "no valid recipients" (554) reply in response to the
4520 The example in the pipelining RFC 2920 uses 554, but I use 503 here
4521 because it is the same whether pipelining is in use or not.
4523 If all the RCPT commands that precede DATA provoked the same error message
4524 (often indicating some kind of system error), it is helpful to include it
4525 with the DATA rejection (an idea suggested by Tony Finch). */
4529 if (!discarded && recipients_count <= 0)
4531 if (rcpt_smtp_response_same && rcpt_smtp_response != NULL)
4533 uschar *code = US"503";
4534 int len = Ustrlen(rcpt_smtp_response);
4535 smtp_respond(code, 3, FALSE, US"All RCPT commands were rejected with "
4537 /* Responses from smtp_printf() will have \r\n on the end */
4538 if (len > 2 && rcpt_smtp_response[len-2] == '\r')
4539 rcpt_smtp_response[len-2] = 0;
4540 smtp_respond(code, 3, FALSE, rcpt_smtp_response);
4542 if (pipelining_advertised && last_was_rcpt)
4543 smtp_printf("503 Valid RCPT command must precede DATA\r\n");
4545 done = synprot_error(L_smtp_protocol_error, 503, NULL,
4546 US"valid RCPT command must precede DATA");
4550 if (toomany && recipients_max_reject)
4552 sender_address = NULL; /* This will allow a new MAIL without RSET */
4553 sender_address_unrewritten = NULL;
4554 smtp_printf("554 Too many recipients\r\n");
4558 /* If there is an ACL, re-check the synchronization afterwards, since the
4559 ACL may have delayed. To handle cutthrough delivery enforce a dummy call
4560 to get the DATA command sent. */
4562 if (acl_smtp_predata == NULL && cutthrough.fd < 0) rc = OK; else
4564 uschar * acl= acl_smtp_predata ? acl_smtp_predata : US"accept";
4565 enable_dollar_recipients = TRUE;
4566 rc = acl_check(ACL_WHERE_PREDATA, NULL, acl, &user_msg,
4568 enable_dollar_recipients = FALSE;
4569 if (rc == OK && !check_sync()) goto SYNC_FAILURE;
4576 if (user_msg == NULL)
4577 smtp_printf("%s Enter message, ending with \".\" on a line by itself\r\n", code);
4578 else smtp_user_msg(code, user_msg);
4580 message_ended = END_NOTENDED; /* Indicate in middle of data */
4583 /* Either the ACL failed the address, or it was deferred. */
4586 done = smtp_handle_acl_fail(ACL_WHERE_PREDATA, rc, user_msg, log_msg);
4596 if (!(address = parse_extract_address(smtp_cmd_data, &errmess,
4597 &start, &end, &recipient_domain, FALSE)))
4599 smtp_printf("501 %s\r\n", errmess);
4603 if (recipient_domain == 0)
4604 if (!(recipient_domain = qualify_recipient(&address, smtp_cmd_data,
4608 if ((rc = acl_check(ACL_WHERE_VRFY, address, acl_smtp_vrfy,
4609 &user_msg, &log_msg)) != OK)
4610 done = smtp_handle_acl_fail(ACL_WHERE_VRFY, rc, user_msg, log_msg);
4614 address_item * addr = deliver_make_addr(address, FALSE);
4616 switch(verify_address(addr, NULL, vopt_is_recipient | vopt_qualify, -1,
4617 -1, -1, NULL, NULL, NULL))
4620 s = string_sprintf("250 <%s> is deliverable", address);
4624 s = (addr->user_message != NULL)?
4625 string_sprintf("451 <%s> %s", address, addr->user_message) :
4626 string_sprintf("451 Cannot resolve <%s> at this time", address);
4630 s = (addr->user_message != NULL)?
4631 string_sprintf("550 <%s> %s", address, addr->user_message) :
4632 string_sprintf("550 <%s> is not deliverable", address);
4633 log_write(0, LOG_MAIN, "VRFY failed for %s %s",
4634 smtp_cmd_argument, host_and_ident(TRUE));
4638 smtp_printf("%s\r\n", s);
4646 rc = acl_check(ACL_WHERE_EXPN, NULL, acl_smtp_expn, &user_msg, &log_msg);
4648 done = smtp_handle_acl_fail(ACL_WHERE_EXPN, rc, user_msg, log_msg);
4651 BOOL save_log_testing_mode = log_testing_mode;
4652 address_test_mode = log_testing_mode = TRUE;
4653 (void) verify_address(deliver_make_addr(smtp_cmd_data, FALSE),
4654 smtp_out, vopt_is_recipient | vopt_qualify | vopt_expn, -1, -1, -1,
4656 address_test_mode = FALSE;
4657 log_testing_mode = save_log_testing_mode; /* true for -bh */
4666 if (!tls_advertised)
4668 done = synprot_error(L_smtp_protocol_error, 503, NULL,
4669 US"STARTTLS command used when not advertised");
4673 /* Apply an ACL check if one is defined */
4675 if ( acl_smtp_starttls
4676 && (rc = acl_check(ACL_WHERE_STARTTLS, NULL, acl_smtp_starttls,
4677 &user_msg, &log_msg)) != OK
4680 done = smtp_handle_acl_fail(ACL_WHERE_STARTTLS, rc, user_msg, log_msg);
4684 /* RFC 2487 is not clear on when this command may be sent, though it
4685 does state that all information previously obtained from the client
4686 must be discarded if a TLS session is started. It seems reasonble to
4687 do an implied RSET when STARTTLS is received. */
4689 incomplete_transaction_log(US"STARTTLS");
4690 smtp_reset(reset_point);
4692 cmd_list[CMD_LIST_STARTTLS].is_mail_cmd = FALSE;
4694 /* There's an attack where more data is read in past the STARTTLS command
4695 before TLS is negotiated, then assumed to be part of the secure session
4696 when used afterwards; we use segregated input buffers, so are not
4697 vulnerable, but we want to note when it happens and, for sheer paranoia,
4698 ensure that the buffer is "wiped".
4699 Pipelining sync checks will normally have protected us too, unless disabled
4700 by configuration. */
4702 if (receive_smtp_buffered())
4705 debug_printf("Non-empty input buffer after STARTTLS; naive attack?");
4706 if (tls_in.active < 0)
4707 smtp_inend = smtp_inptr = smtp_inbuffer;
4708 /* and if TLS is already active, tls_server_start() should fail */
4711 /* There is nothing we value in the input buffer and if TLS is succesfully
4712 negotiated, we won't use this buffer again; if TLS fails, we'll just read
4713 fresh content into it. The buffer contains arbitrary content from an
4714 untrusted remote source; eg: NOOP <shellcode>\r\nSTARTTLS\r\n
4715 It seems safest to just wipe away the content rather than leave it as a
4716 target to jump to. */
4718 memset(smtp_inbuffer, 0, in_buffer_size);
4720 /* Attempt to start up a TLS session, and if successful, discard all
4721 knowledge that was obtained previously. At least, that's what the RFC says,
4722 and that's what happens by default. However, in order to work round YAEB,
4723 there is an option to remember the esmtp state. Sigh.
4725 We must allow for an extra EHLO command and an extra AUTH command after
4726 STARTTLS that don't add to the nonmail command count. */
4728 if ((rc = tls_server_start(tls_require_ciphers)) == OK)
4730 if (!tls_remember_esmtp)
4731 helo_seen = esmtp = auth_advertised = pipelining_advertised = FALSE;
4732 cmd_list[CMD_LIST_EHLO].is_mail_cmd = TRUE;
4733 cmd_list[CMD_LIST_AUTH].is_mail_cmd = TRUE;
4734 cmd_list[CMD_LIST_TLS_AUTH].is_mail_cmd = TRUE;
4735 if (sender_helo_name != NULL)
4737 store_free(sender_helo_name);
4738 sender_helo_name = NULL;
4739 host_build_sender_fullhost(); /* Rebuild */
4740 set_process_info("handling incoming TLS connection from %s",
4741 host_and_ident(FALSE));
4744 (sender_host_address ? protocols : protocols_local)
4746 ? pextend + (sender_host_authenticated ? pauthed : 0)
4748 + (tls_in.active >= 0 ? pcrpted : 0)
4751 sender_host_authenticated = NULL;
4752 authenticated_id = NULL;
4753 sync_cmd_limit = NON_SYNC_CMD_NON_PIPELINING;
4754 DEBUG(D_tls) debug_printf("TLS active\n");
4755 break; /* Successful STARTTLS */
4758 /* Some local configuration problem was discovered before actually trying
4759 to do a TLS handshake; give a temporary error. */
4761 else if (rc == DEFER)
4763 smtp_printf("454 TLS currently unavailable\r\n");
4767 /* Hard failure. Reject everything except QUIT or closed connection. One
4768 cause for failure is a nested STARTTLS, in which case tls_in.active remains
4769 set, but we must still reject all incoming commands. */
4771 DEBUG(D_tls) debug_printf("TLS failed to start\n");
4774 switch(smtp_read_command(FALSE))
4777 log_write(L_smtp_connection, LOG_MAIN, "%s closed by EOF",
4778 smtp_get_connection_info());
4779 smtp_notquit_exit(US"tls-failed", NULL, NULL);
4783 /* It is perhaps arguable as to which exit ACL should be called here,
4784 but as it is probably a situation that almost never arises, it
4785 probably doesn't matter. We choose to call the real QUIT ACL, which in
4786 some sense is perhaps "right". */
4790 if (acl_smtp_quit != NULL)
4792 rc = acl_check(ACL_WHERE_QUIT, NULL, acl_smtp_quit, &user_msg,
4795 log_write(0, LOG_MAIN|LOG_PANIC, "ACL for QUIT returned ERROR: %s",
4798 if (user_msg == NULL)
4799 smtp_printf("221 %s closing connection\r\n", smtp_active_hostname);
4801 smtp_respond(US"221", 3, TRUE, user_msg);
4802 log_write(L_smtp_connection, LOG_MAIN, "%s closed by QUIT",
4803 smtp_get_connection_info());
4808 smtp_printf("554 Security failure\r\n");
4812 tls_close(TRUE, TRUE);
4817 /* The ACL for QUIT is provided for gathering statistical information or
4818 similar; it does not affect the response code, but it can supply a custom
4823 incomplete_transaction_log(US"QUIT");
4824 if (acl_smtp_quit != NULL)
4826 rc = acl_check(ACL_WHERE_QUIT, NULL, acl_smtp_quit, &user_msg, &log_msg);
4828 log_write(0, LOG_MAIN|LOG_PANIC, "ACL for QUIT returned ERROR: %s",
4831 if (user_msg == NULL)
4832 smtp_printf("221 %s closing connection\r\n", smtp_active_hostname);
4834 smtp_respond(US"221", 3, TRUE, user_msg);
4837 tls_close(TRUE, TRUE);
4841 log_write(L_smtp_connection, LOG_MAIN, "%s closed by QUIT",
4842 smtp_get_connection_info());
4848 incomplete_transaction_log(US"RSET");
4849 smtp_reset(reset_point);
4851 smtp_printf("250 Reset OK\r\n");
4852 cmd_list[CMD_LIST_RSET].is_mail_cmd = FALSE;
4858 smtp_printf("250 OK\r\n");
4862 /* Show ETRN/EXPN/VRFY if there's an ACL for checking hosts; if actually
4863 used, a check will be done for permitted hosts. Show STARTTLS only if not
4864 already in a TLS session and if it would be advertised in the EHLO
4869 smtp_printf("214-Commands supported:\r\n");
4873 Ustrcat(buffer, " AUTH");
4875 if (tls_in.active < 0 &&
4876 verify_check_host(&tls_advertise_hosts) != FAIL)
4877 Ustrcat(buffer, " STARTTLS");
4879 Ustrcat(buffer, " HELO EHLO MAIL RCPT DATA");
4880 Ustrcat(buffer, " NOOP QUIT RSET HELP");
4881 if (acl_smtp_etrn != NULL) Ustrcat(buffer, " ETRN");
4882 if (acl_smtp_expn != NULL) Ustrcat(buffer, " EXPN");
4883 if (acl_smtp_vrfy != NULL) Ustrcat(buffer, " VRFY");
4884 smtp_printf("214%s\r\n", buffer);
4890 incomplete_transaction_log(US"connection lost");
4891 smtp_notquit_exit(US"connection-lost", US"421",
4892 US"%s lost input connection", smtp_active_hostname);
4894 /* Don't log by default unless in the middle of a message, as some mailers
4895 just drop the call rather than sending QUIT, and it clutters up the logs.
4898 if (sender_address != NULL || recipients_count > 0)
4899 log_write(L_lost_incoming_connection,
4901 "unexpected %s while reading SMTP command from %s%s",
4902 sender_host_unknown? "EOF" : "disconnection",
4903 host_and_ident(FALSE), smtp_read_error);
4905 else log_write(L_smtp_connection, LOG_MAIN, "%s lost%s",
4906 smtp_get_connection_info(), smtp_read_error);
4914 if (sender_address != NULL)
4916 done = synprot_error(L_smtp_protocol_error, 503, NULL,
4917 US"ETRN is not permitted inside a transaction");
4921 log_write(L_etrn, LOG_MAIN, "ETRN %s received from %s", smtp_cmd_argument,
4922 host_and_ident(FALSE));
4924 if ((rc = acl_check(ACL_WHERE_ETRN, NULL, acl_smtp_etrn,
4925 &user_msg, &log_msg)) != OK)
4927 done = smtp_handle_acl_fail(ACL_WHERE_ETRN, rc, user_msg, log_msg);
4931 /* Compute the serialization key for this command. */
4933 etrn_serialize_key = string_sprintf("etrn-%s\n", smtp_cmd_data);
4935 /* If a command has been specified for running as a result of ETRN, we
4936 permit any argument to ETRN. If not, only the # standard form is permitted,
4937 since that is strictly the only kind of ETRN that can be implemented
4938 according to the RFC. */
4940 if (smtp_etrn_command != NULL)
4944 etrn_command = smtp_etrn_command;
4945 deliver_domain = smtp_cmd_data;
4946 rc = transport_set_up_command(&argv, smtp_etrn_command, TRUE, 0, NULL,
4947 US"ETRN processing", &error);
4948 deliver_domain = NULL;
4951 log_write(0, LOG_MAIN|LOG_PANIC, "failed to set up ETRN command: %s",
4953 smtp_printf("458 Internal failure\r\n");
4958 /* Else set up to call Exim with the -R option. */
4962 if (*smtp_cmd_data++ != '#')
4964 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4965 US"argument must begin with #");
4968 etrn_command = US"exim -R";
4969 argv = CUSS child_exec_exim(CEE_RETURN_ARGV, TRUE, NULL, TRUE,
4970 *queue_name ? 4 : 2,
4971 US"-R", smtp_cmd_data,
4972 US"-MCG", queue_name);
4975 /* If we are host-testing, don't actually do anything. */
4981 debug_printf("ETRN command is: %s\n", etrn_command);
4982 debug_printf("ETRN command execution skipped\n");
4984 if (user_msg == NULL) smtp_printf("250 OK\r\n");
4985 else smtp_user_msg(US"250", user_msg);
4990 /* If ETRN queue runs are to be serialized, check the database to
4991 ensure one isn't already running. */
4993 if (smtp_etrn_serialize && !enq_start(etrn_serialize_key, 1))
4995 smtp_printf("458 Already processing %s\r\n", smtp_cmd_data);
4999 /* Fork a child process and run the command. We don't want to have to
5000 wait for the process at any point, so set SIGCHLD to SIG_IGN before
5001 forking. It should be set that way anyway for external incoming SMTP,
5002 but we save and restore to be tidy. If serialization is required, we
5003 actually run the command in yet another process, so we can wait for it
5004 to complete and then remove the serialization lock. */
5006 oldsignal = signal(SIGCHLD, SIG_IGN);
5008 if ((pid = fork()) == 0)
5010 smtp_input = FALSE; /* This process is not associated with the */
5011 (void)fclose(smtp_in); /* SMTP call any more. */
5012 (void)fclose(smtp_out);
5014 signal(SIGCHLD, SIG_DFL); /* Want to catch child */
5016 /* If not serializing, do the exec right away. Otherwise, fork down
5017 into another process. */
5019 if (!smtp_etrn_serialize || (pid = fork()) == 0)
5021 DEBUG(D_exec) debug_print_argv(argv);
5022 exim_nullstd(); /* Ensure std{in,out,err} exist */
5023 execv(CS argv[0], (char *const *)argv);
5024 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "exec of \"%s\" (ETRN) failed: %s",
5025 etrn_command, strerror(errno));
5026 _exit(EXIT_FAILURE); /* paranoia */
5029 /* Obey this if smtp_serialize and the 2nd fork yielded non-zero. That
5030 is, we are in the first subprocess, after forking again. All we can do
5031 for a failing fork is to log it. Otherwise, wait for the 2nd process to
5032 complete, before removing the serialization. */
5035 log_write(0, LOG_MAIN|LOG_PANIC, "2nd fork for serialized ETRN "
5036 "failed: %s", strerror(errno));
5040 DEBUG(D_any) debug_printf("waiting for serialized ETRN process %d\n",
5042 (void)wait(&status);
5043 DEBUG(D_any) debug_printf("serialized ETRN process %d ended\n",
5047 enq_end(etrn_serialize_key);
5048 _exit(EXIT_SUCCESS);
5051 /* Back in the top level SMTP process. Check that we started a subprocess
5052 and restore the signal state. */
5056 log_write(0, LOG_MAIN|LOG_PANIC, "fork of process for ETRN failed: %s",
5058 smtp_printf("458 Unable to fork process\r\n");
5059 if (smtp_etrn_serialize) enq_end(etrn_serialize_key);
5063 if (user_msg == NULL) smtp_printf("250 OK\r\n");
5064 else smtp_user_msg(US"250", user_msg);
5067 signal(SIGCHLD, oldsignal);
5072 done = synprot_error(L_smtp_syntax_error, 501, NULL,
5073 US"unexpected argument data");
5077 /* This currently happens only for NULLs, but could be extended. */
5080 done = synprot_error(L_smtp_syntax_error, 0, NULL, /* Just logs */
5081 US"NULL character(s) present (shown as '?')");
5082 smtp_printf("501 NULL characters are not allowed in SMTP commands\r\n");
5088 if (smtp_inend >= smtp_inbuffer + in_buffer_size)
5089 smtp_inend = smtp_inbuffer + in_buffer_size - 1;
5090 c = smtp_inend - smtp_inptr;
5091 if (c > 150) c = 150;
5093 incomplete_transaction_log(US"sync failure");
5094 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP protocol synchronization error "
5095 "(next input sent too soon: pipelining was%s advertised): "
5096 "rejected \"%s\" %s next input=\"%s\"",
5097 pipelining_advertised? "" : " not",
5098 smtp_cmd_buffer, host_and_ident(TRUE),
5099 string_printing(smtp_inptr));
5100 smtp_notquit_exit(US"synchronization-error", US"554",
5101 US"SMTP synchronization error");
5102 done = 1; /* Pretend eof - drops connection */
5106 case TOO_MANY_NONMAIL_CMD:
5107 s = smtp_cmd_buffer;
5108 while (*s != 0 && !isspace(*s)) s++;
5109 incomplete_transaction_log(US"too many non-mail commands");
5110 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
5111 "nonmail commands (last was \"%.*s\")", host_and_ident(FALSE),
5112 (int)(s - smtp_cmd_buffer), smtp_cmd_buffer);
5113 smtp_notquit_exit(US"bad-commands", US"554", US"Too many nonmail commands");
5114 done = 1; /* Pretend eof - drops connection */
5117 #ifdef SUPPORT_PROXY
5118 case PROXY_FAIL_IGNORE_CMD:
5119 smtp_printf("503 Command refused, required Proxy negotiation failed\r\n");
5124 if (unknown_command_count++ >= smtp_max_unknown_commands)
5126 log_write(L_smtp_syntax_error, LOG_MAIN,
5127 "SMTP syntax error in \"%s\" %s %s",
5128 string_printing(smtp_cmd_buffer), host_and_ident(TRUE),
5129 US"unrecognized command");
5130 incomplete_transaction_log(US"unrecognized command");
5131 smtp_notquit_exit(US"bad-commands", US"500",
5132 US"Too many unrecognized commands");
5134 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
5135 "unrecognized commands (last was \"%s\")", host_and_ident(FALSE),
5136 string_printing(smtp_cmd_buffer));
5139 done = synprot_error(L_smtp_syntax_error, 500, NULL,
5140 US"unrecognized command");
5144 /* This label is used by goto's inside loops that want to break out to
5145 the end of the command-processing loop. */
5148 last_was_rej_mail = was_rej_mail; /* Remember some last commands for */
5149 last_was_rcpt = was_rcpt; /* protocol error handling */
5153 return done - 2; /* Convert yield values */
5158 /* End of smtp_in.c */