1 /*************************************************
2 * Exim - an Internet mail transport agent *
3 *************************************************/
5 /* Copyright (c) University of Cambridge 1995 - 2015 */
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 #ifndef DISABLE_PRDR
1524 prdr_requested = FALSE;
1527 /* Reset the DSN flags */
1531 authenticated_sender = NULL;
1532 #ifdef EXPERIMENTAL_BRIGHTMAIL
1534 bmi_verdicts = NULL;
1536 #ifndef DISABLE_DKIM
1537 dkim_signers = NULL;
1538 dkim_disable_verify = FALSE;
1539 dkim_collect_input = FALSE;
1541 #ifdef EXPERIMENTAL_SPF
1542 spf_header_comment = NULL;
1543 spf_received = NULL;
1545 spf_smtp_comment = NULL;
1548 message_smtputf8 = FALSE;
1550 body_linecount = body_zerocount = 0;
1552 sender_rate = sender_rate_limit = sender_rate_period = NULL;
1553 ratelimiters_mail = NULL; /* Updated by ratelimit ACL condition */
1554 /* Note that ratelimiters_conn persists across resets. */
1556 /* Reset message ACL variables */
1560 /* The message body variables use malloc store. They may be set if this is
1561 not the first message in an SMTP session and the previous message caused them
1562 to be referenced in an ACL. */
1564 if (message_body != NULL)
1566 store_free(message_body);
1567 message_body = NULL;
1570 if (message_body_end != NULL)
1572 store_free(message_body_end);
1573 message_body_end = NULL;
1576 /* Warning log messages are also saved in malloc store. They are saved to avoid
1577 repetition in the same message, but it seems right to repeat them for different
1580 while (acl_warn_logged != NULL)
1582 string_item *this = acl_warn_logged;
1583 acl_warn_logged = acl_warn_logged->next;
1592 /*************************************************
1593 * Initialize for incoming batched SMTP message *
1594 *************************************************/
1596 /* This function is called from smtp_setup_msg() in the case when
1597 smtp_batched_input is true. This happens when -bS is used to pass a whole batch
1598 of messages in one file with SMTP commands between them. All errors must be
1599 reported by sending a message, and only MAIL FROM, RCPT TO, and DATA are
1600 relevant. After an error on a sender, or an invalid recipient, the remainder
1601 of the message is skipped. The value of received_protocol is already set.
1604 Returns: > 0 message successfully started (reached DATA)
1605 = 0 QUIT read or end of file reached
1606 < 0 should not occur
1610 smtp_setup_batch_msg(void)
1613 void *reset_point = store_get(0);
1615 /* Save the line count at the start of each transaction - single commands
1616 like HELO and RSET count as whole transactions. */
1618 bsmtp_transaction_linecount = receive_linecount;
1620 if ((receive_feof)()) return 0; /* Treat EOF as QUIT */
1622 smtp_reset(reset_point); /* Reset for start of message */
1624 /* Deal with SMTP commands. This loop is exited by setting done to a POSITIVE
1625 value. The values are 2 larger than the required yield of the function. */
1630 uschar *recipient = NULL;
1631 int start, end, sender_domain, recipient_domain;
1633 switch(smtp_read_command(FALSE))
1635 /* The HELO/EHLO commands set sender_address_helo if they have
1636 valid data; otherwise they are ignored, except that they do
1637 a reset of the state. */
1642 check_helo(smtp_cmd_data);
1646 smtp_reset(reset_point);
1647 bsmtp_transaction_linecount = receive_linecount;
1651 /* The MAIL FROM command requires an address as an operand. All we
1652 do here is to parse it for syntactic correctness. The form "<>" is
1653 a special case which converts into an empty string. The start/end
1654 pointers in the original are not used further for this address, as
1655 it is the canonical extracted address which is all that is kept. */
1658 smtp_mailcmd_count++; /* Count for no-mail log */
1659 if (sender_address != NULL)
1660 /* The function moan_smtp_batch() does not return. */
1661 moan_smtp_batch(smtp_cmd_buffer, "503 Sender already given");
1663 if (smtp_cmd_data[0] == 0)
1664 /* The function moan_smtp_batch() does not return. */
1665 moan_smtp_batch(smtp_cmd_buffer, "501 MAIL FROM must have an address operand");
1667 /* Reset to start of message */
1669 smtp_reset(reset_point);
1671 /* Apply SMTP rewrite */
1673 raw_sender = ((rewrite_existflags & rewrite_smtp) != 0)?
1674 rewrite_one(smtp_cmd_data, rewrite_smtp|rewrite_smtp_sender, NULL, FALSE,
1675 US"", global_rewrite_rules) : smtp_cmd_data;
1677 /* Extract the address; the TRUE flag allows <> as valid */
1680 parse_extract_address(raw_sender, &errmess, &start, &end, &sender_domain,
1683 if (raw_sender == NULL)
1684 /* The function moan_smtp_batch() does not return. */
1685 moan_smtp_batch(smtp_cmd_buffer, "501 %s", errmess);
1687 sender_address = string_copy(raw_sender);
1689 /* Qualify unqualified sender addresses if permitted to do so. */
1691 if (sender_domain == 0 && sender_address[0] != 0 && sender_address[0] != '@')
1693 if (allow_unqualified_sender)
1695 sender_address = rewrite_address_qualify(sender_address, FALSE);
1696 DEBUG(D_receive) debug_printf("unqualified address %s accepted "
1697 "and rewritten\n", raw_sender);
1699 /* The function moan_smtp_batch() does not return. */
1700 else moan_smtp_batch(smtp_cmd_buffer, "501 sender address must contain "
1706 /* The RCPT TO command requires an address as an operand. All we do
1707 here is to parse it for syntactic correctness. There may be any number
1708 of RCPT TO commands, specifying multiple senders. We build them all into
1709 a data structure that is in argc/argv format. The start/end values
1710 given by parse_extract_address are not used, as we keep only the
1711 extracted address. */
1714 if (sender_address == NULL)
1715 /* The function moan_smtp_batch() does not return. */
1716 moan_smtp_batch(smtp_cmd_buffer, "503 No sender yet given");
1718 if (smtp_cmd_data[0] == 0)
1719 /* The function moan_smtp_batch() does not return. */
1720 moan_smtp_batch(smtp_cmd_buffer, "501 RCPT TO must have an address operand");
1722 /* Check maximum number allowed */
1724 if (recipients_max > 0 && recipients_count + 1 > recipients_max)
1725 /* The function moan_smtp_batch() does not return. */
1726 moan_smtp_batch(smtp_cmd_buffer, "%s too many recipients",
1727 recipients_max_reject? "552": "452");
1729 /* Apply SMTP rewrite, then extract address. Don't allow "<>" as a
1730 recipient address */
1732 recipient = ((rewrite_existflags & rewrite_smtp) != 0)?
1733 rewrite_one(smtp_cmd_data, rewrite_smtp, NULL, FALSE, US"",
1734 global_rewrite_rules) : smtp_cmd_data;
1736 /* rfc821_domains = TRUE; << no longer needed */
1737 recipient = parse_extract_address(recipient, &errmess, &start, &end,
1738 &recipient_domain, FALSE);
1739 /* rfc821_domains = FALSE; << no longer needed */
1741 if (recipient == NULL)
1742 /* The function moan_smtp_batch() does not return. */
1743 moan_smtp_batch(smtp_cmd_buffer, "501 %s", errmess);
1745 /* If the recipient address is unqualified, qualify it if permitted. Then
1746 add it to the list of recipients. */
1748 if (recipient_domain == 0)
1750 if (allow_unqualified_recipient)
1752 DEBUG(D_receive) debug_printf("unqualified address %s accepted\n",
1754 recipient = rewrite_address_qualify(recipient, TRUE);
1756 /* The function moan_smtp_batch() does not return. */
1757 else moan_smtp_batch(smtp_cmd_buffer, "501 recipient address must contain "
1760 receive_add_recipient(recipient, -1);
1764 /* The DATA command is legal only if it follows successful MAIL FROM
1765 and RCPT TO commands. This function is complete when a valid DATA
1766 command is encountered. */
1769 if (sender_address == NULL || recipients_count <= 0)
1771 /* The function moan_smtp_batch() does not return. */
1772 if (sender_address == NULL)
1773 moan_smtp_batch(smtp_cmd_buffer,
1774 "503 MAIL FROM:<sender> command must precede DATA");
1776 moan_smtp_batch(smtp_cmd_buffer,
1777 "503 RCPT TO:<recipient> must precede DATA");
1781 done = 3; /* DATA successfully achieved */
1782 message_ended = END_NOTENDED; /* Indicate in middle of message */
1787 /* The VRFY, EXPN, HELP, ETRN, and NOOP commands are ignored. */
1794 bsmtp_transaction_linecount = receive_linecount;
1805 /* The function moan_smtp_batch() does not return. */
1806 moan_smtp_batch(smtp_cmd_buffer, "501 Unexpected argument data");
1811 /* The function moan_smtp_batch() does not return. */
1812 moan_smtp_batch(smtp_cmd_buffer, "501 Unexpected NULL in SMTP command");
1817 /* The function moan_smtp_batch() does not return. */
1818 moan_smtp_batch(smtp_cmd_buffer, "500 Command unrecognized");
1823 return done - 2; /* Convert yield values */
1829 /*************************************************
1830 * Start an SMTP session *
1831 *************************************************/
1833 /* This function is called at the start of an SMTP session. Thereafter,
1834 smtp_setup_msg() is called to initiate each separate message. This
1835 function does host-specific testing, and outputs the banner line.
1838 Returns: FALSE if the session can not continue; something has
1839 gone wrong, or the connection to the host is blocked
1843 smtp_start_session(void)
1847 uschar *user_msg, *log_msg;
1851 smtp_connection_start = time(NULL);
1852 for (smtp_ch_index = 0; smtp_ch_index < SMTP_HBUFF_SIZE; smtp_ch_index++)
1853 smtp_connection_had[smtp_ch_index] = SCH_NONE;
1856 /* Default values for certain variables */
1858 helo_seen = esmtp = helo_accept_junk = FALSE;
1859 smtp_mailcmd_count = 0;
1860 count_nonmail = TRUE_UNSET;
1861 synprot_error_count = unknown_command_count = nonmail_command_count = 0;
1862 smtp_delay_mail = smtp_rlm_base;
1863 auth_advertised = FALSE;
1864 pipelining_advertised = FALSE;
1865 pipelining_enable = TRUE;
1866 sync_cmd_limit = NON_SYNC_CMD_NON_PIPELINING;
1867 smtp_exit_function_called = FALSE; /* For avoiding loop in not-quit exit */
1869 /* If receiving by -bs from a trusted user, or testing with -bh, we allow
1870 authentication settings from -oMaa to remain in force. */
1872 if (!host_checking && !sender_host_notsocket) sender_host_authenticated = NULL;
1873 authenticated_by = NULL;
1876 tls_in.cipher = tls_in.peerdn = NULL;
1877 tls_in.ourcert = tls_in.peercert = NULL;
1879 tls_in.ocsp = OCSP_NOT_REQ;
1880 tls_advertised = FALSE;
1882 dsn_advertised = FALSE;
1884 smtputf8_advertised = FALSE;
1887 /* Reset ACL connection variables */
1891 /* Allow for trailing 0 in the command and data buffers. */
1893 smtp_cmd_buffer = (uschar *)malloc(2*smtp_cmd_buffer_size + 2);
1894 if (smtp_cmd_buffer == NULL)
1895 log_write(0, LOG_MAIN|LOG_PANIC_DIE,
1896 "malloc() failed for SMTP command buffer");
1897 smtp_cmd_buffer[0] = 0;
1898 smtp_data_buffer = smtp_cmd_buffer + smtp_cmd_buffer_size + 1;
1900 /* For batched input, the protocol setting can be overridden from the
1901 command line by a trusted caller. */
1903 if (smtp_batched_input)
1905 if (received_protocol == NULL) received_protocol = US"local-bsmtp";
1908 /* For non-batched SMTP input, the protocol setting is forced here. It will be
1909 reset later if any of EHLO/AUTH/STARTTLS are received. */
1913 (sender_host_address ? protocols : protocols_local) [pnormal];
1915 /* Set up the buffer for inputting using direct read() calls, and arrange to
1916 call the local functions instead of the standard C ones. */
1918 smtp_inbuffer = (uschar *)malloc(in_buffer_size);
1919 if (smtp_inbuffer == NULL)
1920 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "malloc() failed for SMTP input buffer");
1921 receive_getc = smtp_getc;
1922 receive_ungetc = smtp_ungetc;
1923 receive_feof = smtp_feof;
1924 receive_ferror = smtp_ferror;
1925 receive_smtp_buffered = smtp_buffered;
1926 smtp_inptr = smtp_inend = smtp_inbuffer;
1927 smtp_had_eof = smtp_had_error = 0;
1929 /* Set up the message size limit; this may be host-specific */
1931 thismessage_size_limit = expand_string_integer(message_size_limit, TRUE);
1932 if (expand_string_message != NULL)
1934 if (thismessage_size_limit == -1)
1935 log_write(0, LOG_MAIN|LOG_PANIC, "unable to expand message_size_limit: "
1936 "%s", expand_string_message);
1938 log_write(0, LOG_MAIN|LOG_PANIC, "invalid message_size_limit: "
1939 "%s", expand_string_message);
1940 smtp_closedown(US"Temporary local problem - please try later");
1944 /* When a message is input locally via the -bs or -bS options, sender_host_
1945 unknown is set unless -oMa was used to force an IP address, in which case it
1946 is checked like a real remote connection. When -bs is used from inetd, this
1947 flag is not set, causing the sending host to be checked. The code that deals
1948 with IP source routing (if configured) is never required for -bs or -bS and
1949 the flag sender_host_notsocket is used to suppress it.
1951 If smtp_accept_max and smtp_accept_reserve are set, keep some connections in
1952 reserve for certain hosts and/or networks. */
1954 if (!sender_host_unknown)
1957 BOOL reserved_host = FALSE;
1959 /* Look up IP options (source routing info) on the socket if this is not an
1960 -oMa "host", and if any are found, log them and drop the connection.
1962 Linux (and others now, see below) is different to everyone else, so there
1963 has to be some conditional compilation here. Versions of Linux before 2.1.15
1964 used a structure whose name was "options". Somebody finally realized that
1965 this name was silly, and it got changed to "ip_options". I use the
1966 newer name here, but there is a fudge in the script that sets up os.h
1967 to define a macro in older Linux systems.
1969 Sigh. Linux is a fast-moving target. Another generation of Linux uses
1970 glibc 2, which has chosen ip_opts for the structure name. This is now
1971 really a glibc thing rather than a Linux thing, so the condition name
1972 has been changed to reflect this. It is relevant also to GNU/Hurd.
1974 Mac OS 10.x (Darwin) is like the later glibc versions, but without the
1975 setting of the __GLIBC__ macro, so we can't detect it automatically. There's
1976 a special macro defined in the os.h file.
1978 Some DGUX versions on older hardware appear not to support IP options at
1979 all, so there is now a general macro which can be set to cut out this
1982 How to do this properly in IPv6 is not yet known. */
1984 #if !HAVE_IPV6 && !defined(NO_IP_OPTIONS)
1986 #ifdef GLIBC_IP_OPTIONS
1987 #if (!defined __GLIBC__) || (__GLIBC__ < 2)
1992 #elif defined DARWIN_IP_OPTIONS
1998 if (!host_checking && !sender_host_notsocket)
2001 EXIM_SOCKLEN_T optlen = sizeof(struct ip_options) + MAX_IPOPTLEN;
2002 struct ip_options *ipopt = store_get(optlen);
2004 struct ip_opts ipoptblock;
2005 struct ip_opts *ipopt = &ipoptblock;
2006 EXIM_SOCKLEN_T optlen = sizeof(ipoptblock);
2008 struct ipoption ipoptblock;
2009 struct ipoption *ipopt = &ipoptblock;
2010 EXIM_SOCKLEN_T optlen = sizeof(ipoptblock);
2013 /* Occasional genuine failures of getsockopt() have been seen - for
2014 example, "reset by peer". Therefore, just log and give up on this
2015 call, unless the error is ENOPROTOOPT. This error is given by systems
2016 that have the interfaces but not the mechanism - e.g. GNU/Hurd at the time
2017 of writing. So for that error, carry on - we just can't do an IP options
2020 DEBUG(D_receive) debug_printf("checking for IP options\n");
2022 if (getsockopt(fileno(smtp_out), IPPROTO_IP, IP_OPTIONS, (uschar *)(ipopt),
2025 if (errno != ENOPROTOOPT)
2027 log_write(0, LOG_MAIN, "getsockopt() failed from %s: %s",
2028 host_and_ident(FALSE), strerror(errno));
2029 smtp_printf("451 SMTP service not available\r\n");
2034 /* Deal with any IP options that are set. On the systems I have looked at,
2035 the value of MAX_IPOPTLEN has been 40, meaning that there should never be
2036 more logging data than will fit in big_buffer. Nevertheless, after somebody
2037 questioned this code, I've added in some paranoid checking. */
2039 else if (optlen > 0)
2041 uschar *p = big_buffer;
2042 uschar *pend = big_buffer + big_buffer_size;
2043 uschar *opt, *adptr;
2045 struct in_addr addr;
2048 uschar *optstart = (uschar *)(ipopt->__data);
2050 uschar *optstart = (uschar *)(ipopt->ip_opts);
2052 uschar *optstart = (uschar *)(ipopt->ipopt_list);
2055 DEBUG(D_receive) debug_printf("IP options exist\n");
2057 Ustrcpy(p, "IP options on incoming call:");
2060 for (opt = optstart; opt != NULL &&
2061 opt < (uschar *)(ipopt) + optlen;)
2075 if (!string_format(p, pend-p, " %s [@%s",
2076 (*opt == IPOPT_SSRR)? "SSRR" : "LSRR",
2078 inet_ntoa(*((struct in_addr *)(&(ipopt->faddr))))))
2080 inet_ntoa(ipopt->ip_dst)))
2082 inet_ntoa(ipopt->ipopt_dst)))
2090 optcount = (opt[1] - 3) / sizeof(struct in_addr);
2092 while (optcount-- > 0)
2094 memcpy(&addr, adptr, sizeof(addr));
2095 if (!string_format(p, pend - p - 1, "%s%s",
2096 (optcount == 0)? ":" : "@", inet_ntoa(addr)))
2102 adptr += sizeof(struct in_addr);
2111 if (pend - p < 4 + 3*opt[1]) { opt = NULL; break; }
2114 for (i = 0; i < opt[1]; i++)
2116 sprintf(CS p, "%2.2x ", opt[i]);
2127 log_write(0, LOG_MAIN, "%s", big_buffer);
2129 /* Refuse any call with IP options. This is what tcpwrappers 7.5 does. */
2131 log_write(0, LOG_MAIN|LOG_REJECT,
2132 "connection from %s refused (IP options)", host_and_ident(FALSE));
2134 smtp_printf("554 SMTP service not available\r\n");
2138 /* Length of options = 0 => there are no options */
2140 else DEBUG(D_receive) debug_printf("no IP options found\n");
2142 #endif /* HAVE_IPV6 && !defined(NO_IP_OPTIONS) */
2144 /* Set keep-alive in socket options. The option is on by default. This
2145 setting is an attempt to get rid of some hanging connections that stick in
2146 read() when the remote end (usually a dialup) goes away. */
2148 if (smtp_accept_keepalive && !sender_host_notsocket)
2149 ip_keepalive(fileno(smtp_out), sender_host_address, FALSE);
2151 /* If the current host matches host_lookup, set the name by doing a
2152 reverse lookup. On failure, sender_host_name will be NULL and
2153 host_lookup_failed will be TRUE. This may or may not be serious - optional
2156 if (verify_check_host(&host_lookup) == OK)
2158 (void)host_name_lookup();
2159 host_build_sender_fullhost();
2162 /* Delay this until we have the full name, if it is looked up. */
2164 set_process_info("handling incoming connection from %s",
2165 host_and_ident(FALSE));
2167 /* Expand smtp_receive_timeout, if needed */
2169 if (smtp_receive_timeout_s)
2172 if ( !(exp = expand_string(smtp_receive_timeout_s))
2174 || (smtp_receive_timeout = readconf_readtime(exp, 0, FALSE)) < 0
2176 log_write(0, LOG_MAIN|LOG_PANIC,
2177 "bad value for smtp_receive_timeout: '%s'", exp ? exp : US"");
2180 /* Start up TLS if tls_on_connect is set. This is for supporting the legacy
2181 smtps port for use with older style SSL MTAs. */
2184 if (tls_in.on_connect && tls_server_start(tls_require_ciphers) != OK)
2188 /* Test for explicit connection rejection */
2190 if (verify_check_host(&host_reject_connection) == OK)
2192 log_write(L_connection_reject, LOG_MAIN|LOG_REJECT, "refused connection "
2193 "from %s (host_reject_connection)", host_and_ident(FALSE));
2194 smtp_printf("554 SMTP service not available\r\n");
2198 /* Test with TCP Wrappers if so configured. There is a problem in that
2199 hosts_ctl() returns 0 (deny) under a number of system failure circumstances,
2200 such as disks dying. In these cases, it is desirable to reject with a 4xx
2201 error instead of a 5xx error. There isn't a "right" way to detect such
2202 problems. The following kludge is used: errno is zeroed before calling
2203 hosts_ctl(). If the result is "reject", a 5xx error is given only if the
2204 value of errno is 0 or ENOENT (which happens if /etc/hosts.{allow,deny} does
2207 #ifdef USE_TCP_WRAPPERS
2209 tcp_wrappers_name = expand_string(tcp_wrappers_daemon_name);
2210 if (tcp_wrappers_name == NULL)
2212 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "Expansion of \"%s\" "
2213 "(tcp_wrappers_name) failed: %s", string_printing(tcp_wrappers_name),
2214 expand_string_message);
2216 if (!hosts_ctl(tcp_wrappers_name,
2217 (sender_host_name == NULL)? STRING_UNKNOWN : CS sender_host_name,
2218 (sender_host_address == NULL)? STRING_UNKNOWN : CS sender_host_address,
2219 (sender_ident == NULL)? STRING_UNKNOWN : CS sender_ident))
2221 if (errno == 0 || errno == ENOENT)
2223 HDEBUG(D_receive) debug_printf("tcp wrappers rejection\n");
2224 log_write(L_connection_reject,
2225 LOG_MAIN|LOG_REJECT, "refused connection from %s "
2226 "(tcp wrappers)", host_and_ident(FALSE));
2227 smtp_printf("554 SMTP service not available\r\n");
2231 int save_errno = errno;
2232 HDEBUG(D_receive) debug_printf("tcp wrappers rejected with unexpected "
2233 "errno value %d\n", save_errno);
2234 log_write(L_connection_reject,
2235 LOG_MAIN|LOG_REJECT, "temporarily refused connection from %s "
2236 "(tcp wrappers errno=%d)", host_and_ident(FALSE), save_errno);
2237 smtp_printf("451 Temporary local problem - please try later\r\n");
2243 /* Check for reserved slots. The value of smtp_accept_count has already been
2244 incremented to include this process. */
2246 if (smtp_accept_max > 0 &&
2247 smtp_accept_count > smtp_accept_max - smtp_accept_reserve)
2249 if ((rc = verify_check_host(&smtp_reserve_hosts)) != OK)
2251 log_write(L_connection_reject,
2252 LOG_MAIN, "temporarily refused connection from %s: not in "
2253 "reserve list: connected=%d max=%d reserve=%d%s",
2254 host_and_ident(FALSE), smtp_accept_count - 1, smtp_accept_max,
2255 smtp_accept_reserve, (rc == DEFER)? " (lookup deferred)" : "");
2256 smtp_printf("421 %s: Too many concurrent SMTP connections; "
2257 "please try again later\r\n", smtp_active_hostname);
2260 reserved_host = TRUE;
2263 /* If a load level above which only messages from reserved hosts are
2264 accepted is set, check the load. For incoming calls via the daemon, the
2265 check is done in the superior process if there are no reserved hosts, to
2266 save a fork. In all cases, the load average will already be available
2267 in a global variable at this point. */
2269 if (smtp_load_reserve >= 0 &&
2270 load_average > smtp_load_reserve &&
2272 verify_check_host(&smtp_reserve_hosts) != OK)
2274 log_write(L_connection_reject,
2275 LOG_MAIN, "temporarily refused connection from %s: not in "
2276 "reserve list and load average = %.2f", host_and_ident(FALSE),
2277 (double)load_average/1000.0);
2278 smtp_printf("421 %s: Too much load; please try again later\r\n",
2279 smtp_active_hostname);
2283 /* Determine whether unqualified senders or recipients are permitted
2284 for this host. Unfortunately, we have to do this every time, in order to
2285 set the flags so that they can be inspected when considering qualifying
2286 addresses in the headers. For a site that permits no qualification, this
2287 won't take long, however. */
2289 allow_unqualified_sender =
2290 verify_check_host(&sender_unqualified_hosts) == OK;
2292 allow_unqualified_recipient =
2293 verify_check_host(&recipient_unqualified_hosts) == OK;
2295 /* Determine whether HELO/EHLO is required for this host. The requirement
2296 can be hard or soft. */
2298 helo_required = verify_check_host(&helo_verify_hosts) == OK;
2300 helo_verify = verify_check_host(&helo_try_verify_hosts) == OK;
2302 /* Determine whether this hosts is permitted to send syntactic junk
2303 after a HELO or EHLO command. */
2305 helo_accept_junk = verify_check_host(&helo_accept_junk_hosts) == OK;
2308 /* For batch SMTP input we are now done. */
2310 if (smtp_batched_input) return TRUE;
2312 #ifdef SUPPORT_PROXY
2313 /* If valid Proxy Protocol source is connecting, set up session.
2314 * Failure will not allow any SMTP function other than QUIT. */
2315 proxy_session = FALSE;
2316 proxy_session_failed = FALSE;
2317 if (check_proxy_protocol_host())
2319 if (setup_proxy_protocol_host() == FALSE)
2321 proxy_session_failed = TRUE;
2323 debug_printf("Failure to extract proxied host, only QUIT allowed\n");
2327 sender_host_name = NULL;
2328 (void)host_name_lookup();
2329 host_build_sender_fullhost();
2334 /* Run the ACL if it exists */
2337 if (acl_smtp_connect != NULL)
2340 rc = acl_check(ACL_WHERE_CONNECT, NULL, acl_smtp_connect, &user_msg,
2344 (void)smtp_handle_acl_fail(ACL_WHERE_CONNECT, rc, user_msg, log_msg);
2349 /* Output the initial message for a two-way SMTP connection. It may contain
2350 newlines, which then cause a multi-line response to be given. */
2352 code = US"220"; /* Default status code */
2353 esc = US""; /* Default extended status code */
2354 esclen = 0; /* Length of esc */
2356 if (user_msg == NULL)
2358 s = expand_string(smtp_banner);
2360 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "Expansion of \"%s\" (smtp_banner) "
2361 "failed: %s", smtp_banner, expand_string_message);
2367 smtp_message_code(&code, &codelen, &s, NULL);
2371 esclen = codelen - 4;
2375 /* Remove any terminating newlines; might as well remove trailing space too */
2378 while (p > s && isspace(p[-1])) p--;
2381 /* It seems that CC:Mail is braindead, and assumes that the greeting message
2382 is all contained in a single IP packet. The original code wrote out the
2383 greeting using several calls to fprint/fputc, and on busy servers this could
2384 cause it to be split over more than one packet - which caused CC:Mail to fall
2385 over when it got the second part of the greeting after sending its first
2386 command. Sigh. To try to avoid this, build the complete greeting message
2387 first, and output it in one fell swoop. This gives a better chance of it
2388 ending up as a single packet. */
2390 ss = store_get(size);
2394 do /* At least once, in case we have an empty string */
2397 uschar *linebreak = Ustrchr(p, '\n');
2398 ss = string_cat(ss, &size, &ptr, code, 3);
2399 if (linebreak == NULL)
2402 ss = string_cat(ss, &size, &ptr, US" ", 1);
2406 len = linebreak - p;
2407 ss = string_cat(ss, &size, &ptr, US"-", 1);
2409 ss = string_cat(ss, &size, &ptr, esc, esclen);
2410 ss = string_cat(ss, &size, &ptr, p, len);
2411 ss = string_cat(ss, &size, &ptr, US"\r\n", 2);
2413 if (linebreak != NULL) p++;
2417 ss[ptr] = 0; /* string_cat leaves room for this */
2419 /* Before we write the banner, check that there is no input pending, unless
2420 this synchronisation check is disabled. */
2424 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP protocol "
2425 "synchronization error (input sent without waiting for greeting): "
2426 "rejected connection from %s input=\"%s\"", host_and_ident(TRUE),
2427 string_printing(smtp_inptr));
2428 smtp_printf("554 SMTP synchronization error\r\n");
2432 /* Now output the banner */
2434 smtp_printf("%s", ss);
2442 /*************************************************
2443 * Handle SMTP syntax and protocol errors *
2444 *************************************************/
2446 /* Write to the log for SMTP syntax errors in incoming commands, if configured
2447 to do so. Then transmit the error response. The return value depends on the
2448 number of syntax and protocol errors in this SMTP session.
2451 type error type, given as a log flag bit
2452 code response code; <= 0 means don't send a response
2453 data data to reflect in the response (can be NULL)
2454 errmess the error message
2456 Returns: -1 limit of syntax/protocol errors NOT exceeded
2457 +1 limit of syntax/protocol errors IS exceeded
2459 These values fit in with the values of the "done" variable in the main
2460 processing loop in smtp_setup_msg(). */
2463 synprot_error(int type, int code, uschar *data, uschar *errmess)
2467 log_write(type, LOG_MAIN, "SMTP %s error in \"%s\" %s %s",
2468 (type == L_smtp_syntax_error)? "syntax" : "protocol",
2469 string_printing(smtp_cmd_buffer), host_and_ident(TRUE), errmess);
2471 if (++synprot_error_count > smtp_max_synprot_errors)
2474 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
2475 "syntax or protocol errors (last command was \"%s\")",
2476 host_and_ident(FALSE), string_printing(smtp_cmd_buffer));
2481 smtp_printf("%d%c%s%s%s\r\n", code, (yield == 1)? '-' : ' ',
2482 (data == NULL)? US"" : data, (data == NULL)? US"" : US": ", errmess);
2484 smtp_printf("%d Too many syntax or protocol errors\r\n", code);
2493 /*************************************************
2494 * Log incomplete transactions *
2495 *************************************************/
2497 /* This function is called after a transaction has been aborted by RSET, QUIT,
2498 connection drops or other errors. It logs the envelope information received
2499 so far in order to preserve address verification attempts.
2501 Argument: string to indicate what aborted the transaction
2506 incomplete_transaction_log(uschar *what)
2508 if (sender_address == NULL || /* No transaction in progress */
2509 !LOGGING(smtp_incomplete_transaction))
2512 /* Build list of recipients for logging */
2514 if (recipients_count > 0)
2517 raw_recipients = store_get(recipients_count * sizeof(uschar *));
2518 for (i = 0; i < recipients_count; i++)
2519 raw_recipients[i] = recipients_list[i].address;
2520 raw_recipients_count = recipients_count;
2523 log_write(L_smtp_incomplete_transaction, LOG_MAIN|LOG_SENDER|LOG_RECIPIENTS,
2524 "%s incomplete transaction (%s)", host_and_ident(TRUE), what);
2530 /*************************************************
2531 * Send SMTP response, possibly multiline *
2532 *************************************************/
2534 /* There are, it seems, broken clients out there that cannot handle multiline
2535 responses. If no_multiline_responses is TRUE (it can be set from an ACL), we
2536 output nothing for non-final calls, and only the first line for anything else.
2539 code SMTP code, may involve extended status codes
2540 codelen length of smtp code; if > 4 there's an ESC
2541 final FALSE if the last line isn't the final line
2542 msg message text, possibly containing newlines
2548 smtp_respond(uschar* code, int codelen, BOOL final, uschar *msg)
2553 if (!final && no_multiline_responses) return;
2558 esclen = codelen - 4;
2561 /* If this is the first output for a (non-batch) RCPT command, see if all RCPTs
2562 have had the same. Note: this code is also present in smtp_printf(). It would
2563 be tidier to have it only in one place, but when it was added, it was easier to
2564 do it that way, so as not to have to mess with the code for the RCPT command,
2565 which sometimes uses smtp_printf() and sometimes smtp_respond(). */
2567 if (rcpt_in_progress)
2569 if (rcpt_smtp_response == NULL)
2570 rcpt_smtp_response = string_copy(msg);
2571 else if (rcpt_smtp_response_same &&
2572 Ustrcmp(rcpt_smtp_response, msg) != 0)
2573 rcpt_smtp_response_same = FALSE;
2574 rcpt_in_progress = FALSE;
2577 /* Not output the message, splitting it up into multiple lines if necessary. */
2581 uschar *nl = Ustrchr(msg, '\n');
2584 smtp_printf("%.3s%c%.*s%s\r\n", code, final? ' ':'-', esclen, esc, msg);
2587 else if (nl[1] == 0 || no_multiline_responses)
2589 smtp_printf("%.3s%c%.*s%.*s\r\n", code, final? ' ':'-', esclen, esc,
2590 (int)(nl - msg), msg);
2595 smtp_printf("%.3s-%.*s%.*s\r\n", code, esclen, esc, (int)(nl - msg), msg);
2597 while (isspace(*msg)) msg++;
2605 /*************************************************
2606 * Parse user SMTP message *
2607 *************************************************/
2609 /* This function allows for user messages overriding the response code details
2610 by providing a suitable response code string at the start of the message
2611 user_msg. Check the message for starting with a response code and optionally an
2612 extended status code. If found, check that the first digit is valid, and if so,
2613 change the code pointer and length to use the replacement. An invalid code
2614 causes a panic log; in this case, if the log messages is the same as the user
2615 message, we must also adjust the value of the log message to show the code that
2616 is actually going to be used (the original one).
2618 This function is global because it is called from receive.c as well as within
2621 Note that the code length returned includes the terminating whitespace
2622 character, which is always included in the regex match.
2625 code SMTP code, may involve extended status codes
2626 codelen length of smtp code; if > 4 there's an ESC
2628 log_msg optional log message, to be adjusted with the new SMTP code
2634 smtp_message_code(uschar **code, int *codelen, uschar **msg, uschar **log_msg)
2639 if (msg == NULL || *msg == NULL) return;
2641 n = pcre_exec(regex_smtp_code, NULL, CS *msg, Ustrlen(*msg), 0,
2642 PCRE_EOPT, ovector, sizeof(ovector)/sizeof(int));
2645 if ((*msg)[0] != (*code)[0])
2647 log_write(0, LOG_MAIN|LOG_PANIC, "configured error code starts with "
2648 "incorrect digit (expected %c) in \"%s\"", (*code)[0], *msg);
2649 if (log_msg != NULL && *log_msg == *msg)
2650 *log_msg = string_sprintf("%s %s", *code, *log_msg + ovector[1]);
2655 *codelen = ovector[1]; /* Includes final space */
2657 *msg += ovector[1]; /* Chop the code off the message */
2664 /*************************************************
2665 * Handle an ACL failure *
2666 *************************************************/
2668 /* This function is called when acl_check() fails. As well as calls from within
2669 this module, it is called from receive.c for an ACL after DATA. It sorts out
2670 logging the incident, and sets up the error response. A message containing
2671 newlines is turned into a multiline SMTP response, but for logging, only the
2674 There's a table of default permanent failure response codes to use in
2675 globals.c, along with the table of names. VFRY is special. Despite RFC1123 it
2676 defaults disabled in Exim. However, discussion in connection with RFC 821bis
2677 (aka RFC 2821) has concluded that the response should be 252 in the disabled
2678 state, because there are broken clients that try VRFY before RCPT. A 5xx
2679 response should be given only when the address is positively known to be
2680 undeliverable. Sigh. Also, for ETRN, 458 is given on refusal, and for AUTH,
2683 From Exim 4.63, it is possible to override the response code details by
2684 providing a suitable response code string at the start of the message provided
2685 in user_msg. The code's first digit is checked for validity.
2688 where where the ACL was called from
2690 user_msg a message that can be included in an SMTP response
2691 log_msg a message for logging
2693 Returns: 0 in most cases
2694 2 if the failure code was FAIL_DROP, in which case the
2695 SMTP connection should be dropped (this value fits with the
2696 "done" variable in smtp_setup_msg() below)
2700 smtp_handle_acl_fail(int where, int rc, uschar *user_msg, uschar *log_msg)
2702 BOOL drop = rc == FAIL_DROP;
2706 uschar *sender_info = US"";
2708 #ifdef WITH_CONTENT_SCAN
2709 (where == ACL_WHERE_MIME)? US"during MIME ACL checks" :
2711 (where == ACL_WHERE_PREDATA)? US"DATA" :
2712 (where == ACL_WHERE_DATA)? US"after DATA" :
2713 #ifndef DISABLE_PRDR
2714 (where == ACL_WHERE_PRDR)? US"after DATA PRDR" :
2716 (smtp_cmd_data == NULL)?
2717 string_sprintf("%s in \"connect\" ACL", acl_wherenames[where]) :
2718 string_sprintf("%s %s", acl_wherenames[where], smtp_cmd_data);
2720 if (drop) rc = FAIL;
2722 /* Set the default SMTP code, and allow a user message to change it. */
2724 smtp_code = (rc != FAIL)? US"451" : acl_wherecodes[where];
2725 smtp_message_code(&smtp_code, &codelen, &user_msg, &log_msg);
2727 /* We used to have sender_address here; however, there was a bug that was not
2728 updating sender_address after a rewrite during a verify. When this bug was
2729 fixed, sender_address at this point became the rewritten address. I'm not sure
2730 this is what should be logged, so I've changed to logging the unrewritten
2731 address to retain backward compatibility. */
2733 #ifndef WITH_CONTENT_SCAN
2734 if (where == ACL_WHERE_RCPT || where == ACL_WHERE_DATA)
2736 if (where == ACL_WHERE_RCPT || where == ACL_WHERE_DATA || where == ACL_WHERE_MIME)
2739 sender_info = string_sprintf("F=<%s>%s%s%s%s ",
2740 sender_address_unrewritten ? sender_address_unrewritten : sender_address,
2741 sender_host_authenticated ? US" A=" : US"",
2742 sender_host_authenticated ? sender_host_authenticated : US"",
2743 sender_host_authenticated && authenticated_id ? US":" : US"",
2744 sender_host_authenticated && authenticated_id ? authenticated_id : US""
2748 /* If there's been a sender verification failure with a specific message, and
2749 we have not sent a response about it yet, do so now, as a preliminary line for
2750 failures, but not defers. However, always log it for defer, and log it for fail
2751 unless the sender_verify_fail log selector has been turned off. */
2753 if (sender_verified_failed != NULL &&
2754 !testflag(sender_verified_failed, af_sverify_told))
2756 BOOL save_rcpt_in_progress = rcpt_in_progress;
2757 rcpt_in_progress = FALSE; /* So as not to treat these as the error */
2759 setflag(sender_verified_failed, af_sverify_told);
2761 if (rc != FAIL || LOGGING(sender_verify_fail))
2762 log_write(0, LOG_MAIN|LOG_REJECT, "%s sender verify %s for <%s>%s",
2763 host_and_ident(TRUE),
2764 ((sender_verified_failed->special_action & 255) == DEFER)? "defer":"fail",
2765 sender_verified_failed->address,
2766 (sender_verified_failed->message == NULL)? US"" :
2767 string_sprintf(": %s", sender_verified_failed->message));
2769 if (rc == FAIL && sender_verified_failed->user_message != NULL)
2770 smtp_respond(smtp_code, codelen, FALSE, string_sprintf(
2771 testflag(sender_verified_failed, af_verify_pmfail)?
2772 "Postmaster verification failed while checking <%s>\n%s\n"
2773 "Several RFCs state that you are required to have a postmaster\n"
2774 "mailbox for each mail domain. This host does not accept mail\n"
2775 "from domains whose servers reject the postmaster address."
2777 testflag(sender_verified_failed, af_verify_nsfail)?
2778 "Callback setup failed while verifying <%s>\n%s\n"
2779 "The initial connection, or a HELO or MAIL FROM:<> command was\n"
2780 "rejected. Refusing MAIL FROM:<> does not help fight spam, disregards\n"
2781 "RFC requirements, and stops you from receiving standard bounce\n"
2782 "messages. This host does not accept mail from domains whose servers\n"
2785 "Verification failed for <%s>\n%s",
2786 sender_verified_failed->address,
2787 sender_verified_failed->user_message));
2789 rcpt_in_progress = save_rcpt_in_progress;
2792 /* Sort out text for logging */
2794 log_msg = (log_msg == NULL)? US"" : string_sprintf(": %s", log_msg);
2795 lognl = Ustrchr(log_msg, '\n');
2796 if (lognl != NULL) *lognl = 0;
2798 /* Send permanent failure response to the command, but the code used isn't
2799 always a 5xx one - see comments at the start of this function. If the original
2800 rc was FAIL_DROP we drop the connection and yield 2. */
2802 if (rc == FAIL) smtp_respond(smtp_code, codelen, TRUE, (user_msg == NULL)?
2803 US"Administrative prohibition" : user_msg);
2805 /* Send temporary failure response to the command. Don't give any details,
2806 unless acl_temp_details is set. This is TRUE for a callout defer, a "defer"
2807 verb, and for a header verify when smtp_return_error_details is set.
2809 This conditional logic is all somewhat of a mess because of the odd
2810 interactions between temp_details and return_error_details. One day it should
2811 be re-implemented in a tidier fashion. */
2815 if (acl_temp_details && user_msg != NULL)
2817 if (smtp_return_error_details &&
2818 sender_verified_failed != NULL &&
2819 sender_verified_failed->message != NULL)
2821 smtp_respond(smtp_code, codelen, FALSE, sender_verified_failed->message);
2823 smtp_respond(smtp_code, codelen, TRUE, user_msg);
2826 smtp_respond(smtp_code, codelen, TRUE,
2827 US"Temporary local problem - please try later");
2830 /* Log the incident to the logs that are specified by log_reject_target
2831 (default main, reject). This can be empty to suppress logging of rejections. If
2832 the connection is not forcibly to be dropped, return 0. Otherwise, log why it
2833 is closing if required and return 2. */
2835 if (log_reject_target != 0)
2838 uschar * s = s_tlslog(NULL, NULL, NULL);
2843 log_write(0, log_reject_target, "%s%s %s%srejected %s%s",
2844 host_and_ident(TRUE), s,
2845 sender_info, (rc == FAIL)? US"" : US"temporarily ", what, log_msg);
2848 if (!drop) return 0;
2850 log_write(L_smtp_connection, LOG_MAIN, "%s closed by DROP in ACL",
2851 smtp_get_connection_info());
2853 /* Run the not-quit ACL, but without any custom messages. This should not be a
2854 problem, because we get here only if some other ACL has issued "drop", and
2855 in that case, *its* custom messages will have been used above. */
2857 smtp_notquit_exit(US"acl-drop", NULL, NULL);
2864 /*************************************************
2865 * Handle SMTP exit when QUIT is not given *
2866 *************************************************/
2868 /* This function provides a logging/statistics hook for when an SMTP connection
2869 is dropped on the floor or the other end goes away. It's a global function
2870 because it's called from receive.c as well as this module. As well as running
2871 the NOTQUIT ACL, if there is one, this function also outputs a final SMTP
2872 response, either with a custom message from the ACL, or using a default. There
2873 is one case, however, when no message is output - after "drop". In that case,
2874 the ACL that obeyed "drop" has already supplied the custom message, and NULL is
2875 passed to this function.
2877 In case things go wrong while processing this function, causing an error that
2878 may re-enter this funtion, there is a recursion check.
2881 reason What $smtp_notquit_reason will be set to in the ACL;
2882 if NULL, the ACL is not run
2883 code The error code to return as part of the response
2884 defaultrespond The default message if there's no user_msg
2890 smtp_notquit_exit(uschar *reason, uschar *code, uschar *defaultrespond, ...)
2893 uschar *user_msg = NULL;
2894 uschar *log_msg = NULL;
2896 /* Check for recursive acll */
2898 if (smtp_exit_function_called)
2900 log_write(0, LOG_PANIC, "smtp_notquit_exit() called more than once (%s)",
2904 smtp_exit_function_called = TRUE;
2906 /* Call the not-QUIT ACL, if there is one, unless no reason is given. */
2908 if (acl_smtp_notquit != NULL && reason != NULL)
2910 smtp_notquit_reason = reason;
2911 rc = acl_check(ACL_WHERE_NOTQUIT, NULL, acl_smtp_notquit, &user_msg,
2914 log_write(0, LOG_MAIN|LOG_PANIC, "ACL for not-QUIT returned ERROR: %s",
2918 /* Write an SMTP response if we are expected to give one. As the default
2919 responses are all internal, they should always fit in the buffer, but code a
2920 warning, just in case. Note that string_vformat() still leaves a complete
2921 string, even if it is incomplete. */
2923 if (code != NULL && defaultrespond != NULL)
2925 if (user_msg == NULL)
2929 va_start(ap, defaultrespond);
2930 if (!string_vformat(buffer, sizeof(buffer), CS defaultrespond, ap))
2931 log_write(0, LOG_MAIN|LOG_PANIC, "string too large in smtp_notquit_exit()");
2932 smtp_printf("%s %s\r\n", code, buffer);
2936 smtp_respond(code, 3, TRUE, user_msg);
2944 /*************************************************
2945 * Verify HELO argument *
2946 *************************************************/
2948 /* This function is called if helo_verify_hosts or helo_try_verify_hosts is
2949 matched. It is also called from ACL processing if verify = helo is used and
2950 verification was not previously tried (i.e. helo_try_verify_hosts was not
2951 matched). The result of its processing is to set helo_verified and
2952 helo_verify_failed. These variables should both be FALSE for this function to
2955 Note that EHLO/HELO is legitimately allowed to quote an address literal. Allow
2956 for IPv6 ::ffff: literals.
2959 Returns: TRUE if testing was completed;
2960 FALSE on a temporary failure
2964 smtp_verify_helo(void)
2968 HDEBUG(D_receive) debug_printf("verifying EHLO/HELO argument \"%s\"\n",
2971 if (sender_helo_name == NULL)
2973 HDEBUG(D_receive) debug_printf("no EHLO/HELO command was issued\n");
2976 /* Deal with the case of -bs without an IP address */
2978 else if (sender_host_address == NULL)
2980 HDEBUG(D_receive) debug_printf("no client IP address: assume success\n");
2981 helo_verified = TRUE;
2984 /* Deal with the more common case when there is a sending IP address */
2986 else if (sender_helo_name[0] == '[')
2988 helo_verified = Ustrncmp(sender_helo_name+1, sender_host_address,
2989 Ustrlen(sender_host_address)) == 0;
2994 if (strncmpic(sender_host_address, US"::ffff:", 7) == 0)
2995 helo_verified = Ustrncmp(sender_helo_name + 1,
2996 sender_host_address + 7, Ustrlen(sender_host_address) - 7) == 0;
3001 { if (helo_verified) debug_printf("matched host address\n"); }
3004 /* Do a reverse lookup if one hasn't already given a positive or negative
3005 response. If that fails, or the name doesn't match, try checking with a forward
3010 if (sender_host_name == NULL && !host_lookup_failed)
3011 yield = host_name_lookup() != DEFER;
3013 /* If a host name is known, check it and all its aliases. */
3015 if (sender_host_name)
3016 if ((helo_verified = strcmpic(sender_host_name, sender_helo_name) == 0))
3018 sender_helo_dnssec = sender_host_dnssec;
3019 HDEBUG(D_receive) debug_printf("matched host name\n");
3023 uschar **aliases = sender_host_aliases;
3025 if ((helo_verified = strcmpic(*aliases++, sender_helo_name) == 0))
3027 sender_helo_dnssec = sender_host_dnssec;
3031 HDEBUG(D_receive) if (helo_verified)
3032 debug_printf("matched alias %s\n", *(--aliases));
3035 /* Final attempt: try a forward lookup of the helo name */
3044 h.name = sender_helo_name;
3051 HDEBUG(D_receive) debug_printf("getting IP address for %s\n",
3053 rc = host_find_bydns(&h, NULL, HOST_FIND_BY_A,
3054 NULL, NULL, NULL, &d, NULL, NULL);
3055 if (rc == HOST_FOUND || rc == HOST_FOUND_LOCAL)
3056 for (hh = &h; hh; hh = hh->next)
3057 if (Ustrcmp(hh->address, sender_host_address) == 0)
3059 helo_verified = TRUE;
3060 if (h.dnssec == DS_YES) sender_helo_dnssec = TRUE;
3063 debug_printf("IP address for %s matches calling address\n"
3064 "Forward DNS security status: %sverified\n",
3065 sender_helo_name, sender_helo_dnssec ? "" : "un");
3072 if (!helo_verified) helo_verify_failed = TRUE; /* We've tried ... */
3079 /*************************************************
3080 * Send user response message *
3081 *************************************************/
3083 /* This function is passed a default response code and a user message. It calls
3084 smtp_message_code() to check and possibly modify the response code, and then
3085 calls smtp_respond() to transmit the response. I put this into a function
3086 just to avoid a lot of repetition.
3089 code the response code
3090 user_msg the user message
3096 smtp_user_msg(uschar *code, uschar *user_msg)
3099 smtp_message_code(&code, &len, &user_msg, NULL);
3100 smtp_respond(code, len, TRUE, user_msg);
3106 smtp_in_auth(auth_instance *au, uschar ** s, uschar ** ss)
3108 const uschar *set_id = NULL;
3111 /* Run the checking code, passing the remainder of the command line as
3112 data. Initials the $auth<n> variables as empty. Initialize $0 empty and set
3113 it as the only set numerical variable. The authenticator may set $auth<n>
3114 and also set other numeric variables. The $auth<n> variables are preferred
3115 nowadays; the numerical variables remain for backwards compatibility.
3117 Afterwards, have a go at expanding the set_id string, even if
3118 authentication failed - for bad passwords it can be useful to log the
3119 userid. On success, require set_id to expand and exist, and put it in
3120 authenticated_id. Save this in permanent store, as the working store gets
3121 reset at HELO, RSET, etc. */
3123 for (i = 0; i < AUTH_VARS; i++) auth_vars[i] = NULL;
3125 expand_nlength[0] = 0; /* $0 contains nothing */
3127 rc = (au->info->servercode)(au, smtp_cmd_data);
3128 if (au->set_id) set_id = expand_string(au->set_id);
3129 expand_nmax = -1; /* Reset numeric variables */
3130 for (i = 0; i < AUTH_VARS; i++) auth_vars[i] = NULL; /* Reset $auth<n> */
3132 /* The value of authenticated_id is stored in the spool file and printed in
3133 log lines. It must not contain binary zeros or newline characters. In
3134 normal use, it never will, but when playing around or testing, this error
3135 can (did) happen. To guard against this, ensure that the id contains only
3136 printing characters. */
3138 if (set_id) set_id = string_printing(set_id);
3140 /* For the non-OK cases, set up additional logging data if set_id
3144 set_id = set_id && *set_id
3145 ? string_sprintf(" (set_id=%s)", set_id) : US"";
3147 /* Switch on the result */
3152 if (!au->set_id || set_id) /* Complete success */
3154 if (set_id) authenticated_id = string_copy_malloc(set_id);
3155 sender_host_authenticated = au->name;
3156 authentication_failed = FALSE;
3157 authenticated_fail_id = NULL; /* Impossible to already be set? */
3160 (sender_host_address ? protocols : protocols_local)
3161 [pextend + pauthed + (tls_in.active >= 0 ? pcrpted:0)];
3162 *s = *ss = US"235 Authentication succeeded";
3163 authenticated_by = au;
3167 /* Authentication succeeded, but we failed to expand the set_id string.
3168 Treat this as a temporary error. */
3170 auth_defer_msg = expand_string_message;
3174 if (set_id) authenticated_fail_id = string_copy_malloc(set_id);
3175 *s = string_sprintf("435 Unable to authenticate at present%s",
3176 auth_defer_user_msg);
3177 *ss = string_sprintf("435 Unable to authenticate at present%s: %s",
3178 set_id, auth_defer_msg);
3182 *s = *ss = US"501 Invalid base64 data";
3186 *s = *ss = US"501 Authentication cancelled";
3190 *s = *ss = US"553 Initial data not expected";
3194 if (set_id) authenticated_fail_id = string_copy_malloc(set_id);
3195 *s = US"535 Incorrect authentication data";
3196 *ss = string_sprintf("535 Incorrect authentication data%s", set_id);
3200 if (set_id) authenticated_fail_id = string_copy_malloc(set_id);
3201 *s = US"435 Internal error";
3202 *ss = string_sprintf("435 Internal error%s: return %d from authentication "
3203 "check", set_id, rc);
3212 /*************************************************
3213 * Initialize for SMTP incoming message *
3214 *************************************************/
3216 /* This function conducts the initial dialogue at the start of an incoming SMTP
3217 message, and builds a list of recipients. However, if the incoming message
3218 is part of a batch (-bS option) a separate function is called since it would
3219 be messy having tests splattered about all over this function. This function
3220 therefore handles the case where interaction is occurring. The input and output
3221 files are set up in smtp_in and smtp_out.
3223 The global recipients_list is set to point to a vector of recipient_item
3224 blocks, whose number is given by recipients_count. This is extended by the
3225 receive_add_recipient() function. The global variable sender_address is set to
3226 the sender's address. The yield is +1 if a message has been successfully
3227 started, 0 if a QUIT command was encountered or the connection was refused from
3228 the particular host, or -1 if the connection was lost.
3232 Returns: > 0 message successfully started (reached DATA)
3233 = 0 QUIT read or end of file reached or call refused
3238 smtp_setup_msg(void)
3241 BOOL toomany = FALSE;
3242 BOOL discarded = FALSE;
3243 BOOL last_was_rej_mail = FALSE;
3244 BOOL last_was_rcpt = FALSE;
3245 void *reset_point = store_get(0);
3247 DEBUG(D_receive) debug_printf("smtp_setup_msg entered\n");
3249 /* Reset for start of new message. We allow one RSET not to be counted as a
3250 nonmail command, for those MTAs that insist on sending it between every
3251 message. Ditto for EHLO/HELO and for STARTTLS, to allow for going in and out of
3252 TLS between messages (an Exim client may do this if it has messages queued up
3253 for the host). Note: we do NOT reset AUTH at this point. */
3255 smtp_reset(reset_point);
3256 message_ended = END_NOTSTARTED;
3258 cmd_list[CMD_LIST_RSET].is_mail_cmd = TRUE;
3259 cmd_list[CMD_LIST_HELO].is_mail_cmd = TRUE;
3260 cmd_list[CMD_LIST_EHLO].is_mail_cmd = TRUE;
3262 cmd_list[CMD_LIST_STARTTLS].is_mail_cmd = TRUE;
3263 cmd_list[CMD_LIST_TLS_AUTH].is_mail_cmd = TRUE;
3266 /* Set the local signal handler for SIGTERM - it tries to end off tidily */
3268 os_non_restarting_signal(SIGTERM, command_sigterm_handler);
3270 /* Batched SMTP is handled in a different function. */
3272 if (smtp_batched_input) return smtp_setup_batch_msg();
3274 /* Deal with SMTP commands. This loop is exited by setting done to a POSITIVE
3275 value. The values are 2 larger than the required yield of the function. */
3279 const uschar **argv;
3280 uschar *etrn_command;
3281 uschar *etrn_serialize_key;
3283 uschar *log_msg, *smtp_code;
3284 uschar *user_msg = NULL;
3285 uschar *recipient = NULL;
3286 uschar *hello = NULL;
3288 BOOL was_rej_mail = FALSE;
3289 BOOL was_rcpt = FALSE;
3290 void (*oldsignal)(int);
3292 int start, end, sender_domain, recipient_domain;
3296 uschar *orcpt = NULL;
3299 #if defined(SUPPORT_TLS) && defined(AUTH_TLS)
3300 /* Check once per STARTTLS or SSL-on-connect for a TLS AUTH */
3301 if ( tls_in.active >= 0
3303 && tls_in.certificate_verified
3304 && cmd_list[CMD_LIST_TLS_AUTH].is_mail_cmd
3307 cmd_list[CMD_LIST_TLS_AUTH].is_mail_cmd = FALSE;
3310 rc = acl_check(ACL_WHERE_AUTH, NULL, acl_smtp_auth, &user_msg, &log_msg);
3313 done = smtp_handle_acl_fail(ACL_WHERE_AUTH, rc, user_msg, log_msg);
3318 for (au = auths; au; au = au->next)
3319 if (strcmpic(US"tls", au->driver_name) == 0)
3321 smtp_cmd_data = NULL;
3323 if (smtp_in_auth(au, &s, &ss) == OK)
3324 DEBUG(D_auth) debug_printf("tls auth succeeded\n");
3326 DEBUG(D_auth) debug_printf("tls auth not succeeded\n");
3332 switch(smtp_read_command(TRUE))
3334 /* The AUTH command is not permitted to occur inside a transaction, and may
3335 occur successfully only once per connection. Actually, that isn't quite
3336 true. When TLS is started, all previous information about a connection must
3337 be discarded, so a new AUTH is permitted at that time.
3339 AUTH may only be used when it has been advertised. However, it seems that
3340 there are clients that send AUTH when it hasn't been advertised, some of
3341 them even doing this after HELO. And there are MTAs that accept this. Sigh.
3342 So there's a get-out that allows this to happen.
3344 AUTH is initially labelled as a "nonmail command" so that one occurrence
3345 doesn't get counted. We change the label here so that multiple failing
3346 AUTHS will eventually hit the nonmail threshold. */
3350 authentication_failed = TRUE;
3351 cmd_list[CMD_LIST_AUTH].is_mail_cmd = FALSE;
3353 if (!auth_advertised && !allow_auth_unadvertised)
3355 done = synprot_error(L_smtp_protocol_error, 503, NULL,
3356 US"AUTH command used when not advertised");
3359 if (sender_host_authenticated)
3361 done = synprot_error(L_smtp_protocol_error, 503, NULL,
3362 US"already authenticated");
3367 done = synprot_error(L_smtp_protocol_error, 503, NULL,
3368 US"not permitted in mail transaction");
3376 rc = acl_check(ACL_WHERE_AUTH, NULL, acl_smtp_auth, &user_msg, &log_msg);
3379 done = smtp_handle_acl_fail(ACL_WHERE_AUTH, rc, user_msg, log_msg);
3384 /* Find the name of the requested authentication mechanism. */
3387 while ((c = *smtp_cmd_data) != 0 && !isspace(c))
3389 if (!isalnum(c) && c != '-' && c != '_')
3391 done = synprot_error(L_smtp_syntax_error, 501, NULL,
3392 US"invalid character in authentication mechanism name");
3398 /* If not at the end of the line, we must be at white space. Terminate the
3399 name and move the pointer on to any data that may be present. */
3401 if (*smtp_cmd_data != 0)
3403 *smtp_cmd_data++ = 0;
3404 while (isspace(*smtp_cmd_data)) smtp_cmd_data++;
3407 /* Search for an authentication mechanism which is configured for use
3408 as a server and which has been advertised (unless, sigh, allow_auth_
3409 unadvertised is set). */
3411 for (au = auths; au; au = au->next)
3412 if (strcmpic(s, au->public_name) == 0 && au->server &&
3413 (au->advertised || allow_auth_unadvertised))
3418 c = smtp_in_auth(au, &s, &ss);
3420 smtp_printf("%s\r\n", s);
3422 log_write(0, LOG_MAIN|LOG_REJECT, "%s authenticator failed for %s: %s",
3423 au->name, host_and_ident(FALSE), ss);
3426 done = synprot_error(L_smtp_protocol_error, 504, NULL,
3427 string_sprintf("%s authentication mechanism not supported", s));
3429 break; /* AUTH_CMD */
3431 /* The HELO/EHLO commands are permitted to appear in the middle of a
3432 session as well as at the beginning. They have the effect of a reset in
3433 addition to their other functions. Their absence at the start cannot be
3434 taken to be an error.
3438 If the EHLO command is not acceptable to the SMTP server, 501, 500,
3439 or 502 failure replies MUST be returned as appropriate. The SMTP
3440 server MUST stay in the same state after transmitting these replies
3441 that it was in before the EHLO was received.
3443 Therefore, we do not do the reset until after checking the command for
3444 acceptability. This change was made for Exim release 4.11. Previously
3445 it did the reset first. */
3458 HELO_EHLO: /* Common code for HELO and EHLO */
3459 cmd_list[CMD_LIST_HELO].is_mail_cmd = FALSE;
3460 cmd_list[CMD_LIST_EHLO].is_mail_cmd = FALSE;
3462 /* Reject the HELO if its argument was invalid or non-existent. A
3463 successful check causes the argument to be saved in malloc store. */
3465 if (!check_helo(smtp_cmd_data))
3467 smtp_printf("501 Syntactically invalid %s argument(s)\r\n", hello);
3469 log_write(0, LOG_MAIN|LOG_REJECT, "rejected %s from %s: syntactically "
3470 "invalid argument(s): %s", hello, host_and_ident(FALSE),
3471 (*smtp_cmd_argument == 0)? US"(no argument given)" :
3472 string_printing(smtp_cmd_argument));
3474 if (++synprot_error_count > smtp_max_synprot_errors)
3476 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
3477 "syntax or protocol errors (last command was \"%s\")",
3478 host_and_ident(FALSE), string_printing(smtp_cmd_buffer));
3485 /* If sender_host_unknown is true, we have got here via the -bs interface,
3486 not called from inetd. Otherwise, we are running an IP connection and the
3487 host address will be set. If the helo name is the primary name of this
3488 host and we haven't done a reverse lookup, force one now. If helo_required
3489 is set, ensure that the HELO name matches the actual host. If helo_verify
3490 is set, do the same check, but softly. */
3492 if (!sender_host_unknown)
3494 BOOL old_helo_verified = helo_verified;
3495 uschar *p = smtp_cmd_data;
3497 while (*p != 0 && !isspace(*p)) { *p = tolower(*p); p++; }
3500 /* Force a reverse lookup if HELO quoted something in helo_lookup_domains
3501 because otherwise the log can be confusing. */
3503 if (sender_host_name == NULL &&
3504 (deliver_domain = sender_helo_name, /* set $domain */
3505 match_isinlist(sender_helo_name, CUSS &helo_lookup_domains, 0,
3506 &domainlist_anchor, NULL, MCL_DOMAIN, TRUE, NULL)) == OK)
3507 (void)host_name_lookup();
3509 /* Rebuild the fullhost info to include the HELO name (and the real name
3510 if it was looked up.) */
3512 host_build_sender_fullhost(); /* Rebuild */
3513 set_process_info("handling%s incoming connection from %s",
3514 (tls_in.active >= 0)? " TLS" : "", host_and_ident(FALSE));
3516 /* Verify if configured. This doesn't give much security, but it does
3517 make some people happy to be able to do it. If helo_required is set,
3518 (host matches helo_verify_hosts) failure forces rejection. If helo_verify
3519 is set (host matches helo_try_verify_hosts), it does not. This is perhaps
3520 now obsolescent, since the verification can now be requested selectively
3523 helo_verified = helo_verify_failed = sender_helo_dnssec = FALSE;
3524 if (helo_required || helo_verify)
3526 BOOL tempfail = !smtp_verify_helo();
3531 smtp_printf("%d %s argument does not match calling host\r\n",
3532 tempfail? 451 : 550, hello);
3533 log_write(0, LOG_MAIN|LOG_REJECT, "%srejected \"%s %s\" from %s",
3534 tempfail? "temporarily " : "",
3535 hello, sender_helo_name, host_and_ident(FALSE));
3536 helo_verified = old_helo_verified;
3537 break; /* End of HELO/EHLO processing */
3539 HDEBUG(D_all) debug_printf("%s verification failed but host is in "
3540 "helo_try_verify_hosts\n", hello);
3545 #ifdef EXPERIMENTAL_SPF
3546 /* set up SPF context */
3547 spf_init(sender_helo_name, sender_host_address);
3550 /* Apply an ACL check if one is defined; afterwards, recheck
3551 synchronization in case the client started sending in a delay. */
3553 if (acl_smtp_helo != NULL)
3555 rc = acl_check(ACL_WHERE_HELO, NULL, acl_smtp_helo, &user_msg, &log_msg);
3558 done = smtp_handle_acl_fail(ACL_WHERE_HELO, rc, user_msg, log_msg);
3559 sender_helo_name = NULL;
3560 host_build_sender_fullhost(); /* Rebuild */
3563 else if (!check_sync()) goto SYNC_FAILURE;
3566 /* Generate an OK reply. The default string includes the ident if present,
3567 and also the IP address if present. Reflecting back the ident is intended
3568 as a deterrent to mail forgers. For maximum efficiency, and also because
3569 some broken systems expect each response to be in a single packet, arrange
3570 that the entire reply is sent in one write(). */
3572 auth_advertised = FALSE;
3573 pipelining_advertised = FALSE;
3575 tls_advertised = FALSE;
3577 dsn_advertised = FALSE;
3579 smtputf8_advertised = FALSE;
3582 smtp_code = US"250 "; /* Default response code plus space*/
3583 if (user_msg == NULL)
3585 s = string_sprintf("%.3s %s Hello %s%s%s",
3587 smtp_active_hostname,
3588 (sender_ident == NULL)? US"" : sender_ident,
3589 (sender_ident == NULL)? US"" : US" at ",
3590 (sender_host_name == NULL)? sender_helo_name : sender_host_name);
3595 if (sender_host_address != NULL)
3597 s = string_cat(s, &size, &ptr, US" [", 2);
3598 s = string_cat(s, &size, &ptr, sender_host_address,
3599 Ustrlen(sender_host_address));
3600 s = string_cat(s, &size, &ptr, US"]", 1);
3604 /* A user-supplied EHLO greeting may not contain more than one line. Note
3605 that the code returned by smtp_message_code() includes the terminating
3606 whitespace character. */
3612 smtp_message_code(&smtp_code, &codelen, &user_msg, NULL);
3613 s = string_sprintf("%.*s%s", codelen, smtp_code, user_msg);
3614 if ((ss = strpbrk(CS s, "\r\n")) != NULL)
3616 log_write(0, LOG_MAIN|LOG_PANIC, "EHLO/HELO response must not contain "
3617 "newlines: message truncated: %s", string_printing(s));
3624 s = string_cat(s, &size, &ptr, US"\r\n", 2);
3626 /* If we received EHLO, we must create a multiline response which includes
3627 the functions supported. */
3633 /* I'm not entirely happy with this, as an MTA is supposed to check
3634 that it has enough room to accept a message of maximum size before
3635 it sends this. However, there seems little point in not sending it.
3636 The actual size check happens later at MAIL FROM time. By postponing it
3637 till then, VRFY and EXPN can be used after EHLO when space is short. */
3639 if (thismessage_size_limit > 0)
3641 sprintf(CS big_buffer, "%.3s-SIZE %d\r\n", smtp_code,
3642 thismessage_size_limit);
3643 s = string_cat(s, &size, &ptr, big_buffer, Ustrlen(big_buffer));
3647 s = string_cat(s, &size, &ptr, smtp_code, 3);
3648 s = string_cat(s, &size, &ptr, US"-SIZE\r\n", 7);
3651 /* Exim does not do protocol conversion or data conversion. It is 8-bit
3652 clean; if it has an 8-bit character in its hand, it just sends it. It
3653 cannot therefore specify 8BITMIME and remain consistent with the RFCs.
3654 However, some users want this option simply in order to stop MUAs
3655 mangling messages that contain top-bit-set characters. It is therefore
3656 provided as an option. */
3658 if (accept_8bitmime)
3660 s = string_cat(s, &size, &ptr, smtp_code, 3);
3661 s = string_cat(s, &size, &ptr, US"-8BITMIME\r\n", 11);
3664 /* Advertise DSN support if configured to do so. */
3665 if (verify_check_host(&dsn_advertise_hosts) != FAIL)
3667 s = string_cat(s, &size, &ptr, smtp_code, 3);
3668 s = string_cat(s, &size, &ptr, US"-DSN\r\n", 6);
3669 dsn_advertised = TRUE;
3672 /* Advertise ETRN if there's an ACL checking whether a host is
3673 permitted to issue it; a check is made when any host actually tries. */
3675 if (acl_smtp_etrn != NULL)
3677 s = string_cat(s, &size, &ptr, smtp_code, 3);
3678 s = string_cat(s, &size, &ptr, US"-ETRN\r\n", 7);
3681 /* Advertise EXPN if there's an ACL checking whether a host is
3682 permitted to issue it; a check is made when any host actually tries. */
3684 if (acl_smtp_expn != NULL)
3686 s = string_cat(s, &size, &ptr, smtp_code, 3);
3687 s = string_cat(s, &size, &ptr, US"-EXPN\r\n", 7);
3690 /* Exim is quite happy with pipelining, so let the other end know that
3691 it is safe to use it, unless advertising is disabled. */
3693 if (pipelining_enable &&
3694 verify_check_host(&pipelining_advertise_hosts) == OK)
3696 s = string_cat(s, &size, &ptr, smtp_code, 3);
3697 s = string_cat(s, &size, &ptr, US"-PIPELINING\r\n", 13);
3698 sync_cmd_limit = NON_SYNC_CMD_PIPELINING;
3699 pipelining_advertised = TRUE;
3703 /* If any server authentication mechanisms are configured, advertise
3704 them if the current host is in auth_advertise_hosts. The problem with
3705 advertising always is that some clients then require users to
3706 authenticate (and aren't configurable otherwise) even though it may not
3707 be necessary (e.g. if the host is in host_accept_relay).
3709 RFC 2222 states that SASL mechanism names contain only upper case
3710 letters, so output the names in upper case, though we actually recognize
3711 them in either case in the AUTH command. */
3714 #if defined(SUPPORT_TLS) && defined(AUTH_TLS)
3715 && !sender_host_authenticated
3717 && verify_check_host(&auth_advertise_hosts) == OK
3722 for (au = auths; au; au = au->next)
3723 if (au->server && (au->advertise_condition == NULL ||
3724 expand_check_condition(au->advertise_condition, au->name,
3725 US"authenticator")))
3730 s = string_cat(s, &size, &ptr, smtp_code, 3);
3731 s = string_cat(s, &size, &ptr, US"-AUTH", 5);
3733 auth_advertised = TRUE;
3736 s = string_cat(s, &size, &ptr, US" ", 1);
3737 s = string_cat(s, &size, &ptr, au->public_name,
3738 Ustrlen(au->public_name));
3739 while (++saveptr < ptr) s[saveptr] = toupper(s[saveptr]);
3740 au->advertised = TRUE;
3743 au->advertised = FALSE;
3745 if (!first) s = string_cat(s, &size, &ptr, US"\r\n", 2);
3748 /* Advertise TLS (Transport Level Security) aka SSL (Secure Socket Layer)
3749 if it has been included in the binary, and the host matches
3750 tls_advertise_hosts. We must *not* advertise if we are already in a
3751 secure connection. */
3754 if (tls_in.active < 0 &&
3755 verify_check_host(&tls_advertise_hosts) != FAIL)
3757 s = string_cat(s, &size, &ptr, smtp_code, 3);
3758 s = string_cat(s, &size, &ptr, US"-STARTTLS\r\n", 11);
3759 tls_advertised = TRUE;
3763 #ifndef DISABLE_PRDR
3764 /* Per Recipient Data Response, draft by Eric A. Hall extending RFC */
3767 s = string_cat(s, &size, &ptr, smtp_code, 3);
3768 s = string_cat(s, &size, &ptr, US"-PRDR\r\n", 7);
3773 if ( accept_8bitmime
3774 && verify_check_host(&smtputf8_advertise_hosts) != FAIL)
3776 s = string_cat(s, &size, &ptr, smtp_code, 3);
3777 s = string_cat(s, &size, &ptr, US"-SMTPUTF8\r\n", 11);
3778 smtputf8_advertised = TRUE;
3782 /* Finish off the multiline reply with one that is always available. */
3784 s = string_cat(s, &size, &ptr, smtp_code, 3);
3785 s = string_cat(s, &size, &ptr, US" HELP\r\n", 7);
3788 /* Terminate the string (for debug), write it, and note that HELO/EHLO
3794 if (tls_in.active >= 0) (void)tls_write(TRUE, s, ptr); else
3798 int i = fwrite(s, 1, ptr, smtp_out); i = i; /* compiler quietening */
3803 while ((cr = Ustrchr(s, '\r')) != NULL) /* lose CRs */
3804 memmove(cr, cr + 1, (ptr--) - (cr - s));
3805 debug_printf("SMTP>> %s", s);
3809 /* Reset the protocol and the state, abandoning any previous message. */
3811 (sender_host_address ? protocols : protocols_local)
3813 ? pextend + (sender_host_authenticated ? pauthed : 0)
3815 + (tls_in.active >= 0 ? pcrpted : 0)
3817 smtp_reset(reset_point);
3819 break; /* HELO/EHLO */
3822 /* The MAIL command requires an address as an operand. All we do
3823 here is to parse it for syntactic correctness. The form "<>" is
3824 a special case which converts into an empty string. The start/end
3825 pointers in the original are not used further for this address, as
3826 it is the canonical extracted address which is all that is kept. */
3830 smtp_mailcmd_count++; /* Count for limit and ratelimit */
3831 was_rej_mail = TRUE; /* Reset if accepted */
3832 env_mail_type_t * mail_args; /* Sanity check & validate args */
3834 if (helo_required && !helo_seen)
3836 smtp_printf("503 HELO or EHLO required\r\n");
3837 log_write(0, LOG_MAIN|LOG_REJECT, "rejected MAIL from %s: no "
3838 "HELO/EHLO given", host_and_ident(FALSE));
3842 if (sender_address != NULL)
3844 done = synprot_error(L_smtp_protocol_error, 503, NULL,
3845 US"sender already given");
3849 if (smtp_cmd_data[0] == 0)
3851 done = synprot_error(L_smtp_protocol_error, 501, NULL,
3852 US"MAIL must have an address operand");
3856 /* Check to see if the limit for messages per connection would be
3857 exceeded by accepting further messages. */
3859 if (smtp_accept_max_per_connection > 0 &&
3860 smtp_mailcmd_count > smtp_accept_max_per_connection)
3862 smtp_printf("421 too many messages in this connection\r\n");
3863 log_write(0, LOG_MAIN|LOG_REJECT, "rejected MAIL command %s: too many "
3864 "messages in one connection", host_and_ident(TRUE));
3868 /* Reset for start of message - even if this is going to fail, we
3869 obviously need to throw away any previous data. */
3871 smtp_reset(reset_point);
3873 sender_data = recipient_data = NULL;
3875 /* Loop, checking for ESMTP additions to the MAIL FROM command. */
3879 uschar *name, *value, *end;
3880 unsigned long int size;
3881 BOOL arg_error = FALSE;
3883 if (!extract_option(&name, &value)) break;
3885 for (mail_args = env_mail_type_list;
3886 mail_args->value != ENV_MAIL_OPT_NULL;
3889 if (strcmpic(name, mail_args->name) == 0)
3891 if (mail_args->need_value && strcmpic(value, US"") == 0)
3894 switch(mail_args->value)
3896 /* Handle SIZE= by reading the value. We don't do the check till later,
3897 in order to be able to log the sender address on failure. */
3898 case ENV_MAIL_OPT_SIZE:
3899 if (((size = Ustrtoul(value, &end, 10)), *end == 0))
3901 if ((size == ULONG_MAX && errno == ERANGE) || size > INT_MAX)
3903 message_size = (int)size;
3909 /* If this session was initiated with EHLO and accept_8bitmime is set,
3910 Exim will have indicated that it supports the BODY=8BITMIME option. In
3911 fact, it does not support this according to the RFCs, in that it does not
3912 take any special action for forwarding messages containing 8-bit
3913 characters. That is why accept_8bitmime is not the default setting, but
3914 some sites want the action that is provided. We recognize both "8BITMIME"
3915 and "7BIT" as body types, but take no action. */
3916 case ENV_MAIL_OPT_BODY:
3917 if (accept_8bitmime) {
3918 if (strcmpic(value, US"8BITMIME") == 0)
3920 else if (strcmpic(value, US"7BIT") == 0)
3925 done = synprot_error(L_smtp_syntax_error, 501, NULL,
3926 US"invalid data for BODY");
3929 DEBUG(D_receive) debug_printf("8BITMIME: %d\n", body_8bitmime);
3935 /* Handle the two DSN options, but only if configured to do so (which
3936 will have caused "DSN" to be given in the EHLO response). The code itself
3937 is included only if configured in at build time. */
3939 case ENV_MAIL_OPT_RET:
3942 /* Check if RET has already been set */
3945 synprot_error(L_smtp_syntax_error, 501, NULL,
3946 US"RET can be specified once only");
3949 dsn_ret = strcmpic(value, US"HDRS") == 0
3951 : strcmpic(value, US"FULL") == 0
3954 DEBUG(D_receive) debug_printf("DSN_RET: %d\n", dsn_ret);
3955 /* Check for invalid invalid value, and exit with error */
3958 synprot_error(L_smtp_syntax_error, 501, NULL,
3959 US"Value for RET is invalid");
3964 case ENV_MAIL_OPT_ENVID:
3967 /* Check if the dsn envid has been already set */
3968 if (dsn_envid != NULL)
3970 synprot_error(L_smtp_syntax_error, 501, NULL,
3971 US"ENVID can be specified once only");
3974 dsn_envid = string_copy(value);
3975 DEBUG(D_receive) debug_printf("DSN_ENVID: %s\n", dsn_envid);
3979 /* Handle the AUTH extension. If the value given is not "<>" and either
3980 the ACL says "yes" or there is no ACL but the sending host is
3981 authenticated, we set it up as the authenticated sender. However, if the
3982 authenticator set a condition to be tested, we ignore AUTH on MAIL unless
3983 the condition is met. The value of AUTH is an xtext, which means that +,
3984 = and cntrl chars are coded in hex; however "<>" is unaffected by this
3986 case ENV_MAIL_OPT_AUTH:
3987 if (Ustrcmp(value, "<>") != 0)
3992 if (auth_xtextdecode(value, &authenticated_sender) < 0)
3994 /* Put back terminator overrides for error message */
3997 done = synprot_error(L_smtp_syntax_error, 501, NULL,
3998 US"invalid data for AUTH");
4001 if (acl_smtp_mailauth == NULL)
4003 ignore_msg = US"client not authenticated";
4004 rc = (sender_host_authenticated != NULL)? OK : FAIL;
4008 ignore_msg = US"rejected by ACL";
4009 rc = acl_check(ACL_WHERE_MAILAUTH, NULL, acl_smtp_mailauth,
4010 &user_msg, &log_msg);
4016 if (authenticated_by == NULL ||
4017 authenticated_by->mail_auth_condition == NULL ||
4018 expand_check_condition(authenticated_by->mail_auth_condition,
4019 authenticated_by->name, US"authenticator"))
4020 break; /* Accept the AUTH */
4022 ignore_msg = US"server_mail_auth_condition failed";
4023 if (authenticated_id != NULL)
4024 ignore_msg = string_sprintf("%s: authenticated ID=\"%s\"",
4025 ignore_msg, authenticated_id);
4030 authenticated_sender = NULL;
4031 log_write(0, LOG_MAIN, "ignoring AUTH=%s from %s (%s)",
4032 value, host_and_ident(TRUE), ignore_msg);
4035 /* Should only get DEFER or ERROR here. Put back terminator
4036 overrides for error message */
4041 (void)smtp_handle_acl_fail(ACL_WHERE_MAILAUTH, rc, user_msg,
4048 #ifndef DISABLE_PRDR
4049 case ENV_MAIL_OPT_PRDR:
4051 prdr_requested = TRUE;
4056 case ENV_MAIL_OPT_UTF8:
4057 if (smtputf8_advertised)
4059 DEBUG(D_receive) debug_printf("smtputf8 requested\n");
4060 message_smtputf8 = allow_utf8_domains = TRUE;
4061 received_protocol = string_sprintf("utf8%s", received_protocol);
4065 /* No valid option. Stick back the terminator characters and break
4066 the loop. Do the name-terminator second as extract_option sets
4067 value==name when it found no equal-sign.
4068 An error for a malformed address will occur. */
4069 case ENV_MAIL_OPT_NULL:
4077 /* Break out of for loop if switch() had bad argument or
4078 when start of the email address is reached */
4079 if (arg_error) break;
4082 /* If we have passed the threshold for rate limiting, apply the current
4083 delay, and update it for next time, provided this is a limited host. */
4085 if (smtp_mailcmd_count > smtp_rlm_threshold &&
4086 verify_check_host(&smtp_ratelimit_hosts) == OK)
4088 DEBUG(D_receive) debug_printf("rate limit MAIL: delay %.3g sec\n",
4089 smtp_delay_mail/1000.0);
4090 millisleep((int)smtp_delay_mail);
4091 smtp_delay_mail *= smtp_rlm_factor;
4092 if (smtp_delay_mail > (double)smtp_rlm_limit)
4093 smtp_delay_mail = (double)smtp_rlm_limit;
4096 /* Now extract the address, first applying any SMTP-time rewriting. The
4097 TRUE flag allows "<>" as a sender address. */
4099 raw_sender = rewrite_existflags & rewrite_smtp
4100 ? rewrite_one(smtp_cmd_data, rewrite_smtp, NULL, FALSE, US"",
4101 global_rewrite_rules)
4104 /* rfc821_domains = TRUE; << no longer needed */
4106 parse_extract_address(raw_sender, &errmess, &start, &end, &sender_domain,
4108 /* rfc821_domains = FALSE; << no longer needed */
4110 if (raw_sender == NULL)
4112 done = synprot_error(L_smtp_syntax_error, 501, smtp_cmd_data, errmess);
4116 sender_address = raw_sender;
4118 /* If there is a configured size limit for mail, check that this message
4119 doesn't exceed it. The check is postponed to this point so that the sender
4122 if (thismessage_size_limit > 0 && message_size > thismessage_size_limit)
4124 smtp_printf("552 Message size exceeds maximum permitted\r\n");
4125 log_write(L_size_reject,
4126 LOG_MAIN|LOG_REJECT, "rejected MAIL FROM:<%s> %s: "
4127 "message too big: size%s=%d max=%d",
4129 host_and_ident(TRUE),
4130 (message_size == INT_MAX)? ">" : "",
4132 thismessage_size_limit);
4133 sender_address = NULL;
4137 /* Check there is enough space on the disk unless configured not to.
4138 When smtp_check_spool_space is set, the check is for thismessage_size_limit
4139 plus the current message - i.e. we accept the message only if it won't
4140 reduce the space below the threshold. Add 5000 to the size to allow for
4141 overheads such as the Received: line and storing of recipients, etc.
4142 By putting the check here, even when SIZE is not given, it allow VRFY
4143 and EXPN etc. to be used when space is short. */
4145 if (!receive_check_fs(
4146 (smtp_check_spool_space && message_size >= 0)?
4147 message_size + 5000 : 0))
4149 smtp_printf("452 Space shortage, please try later\r\n");
4150 sender_address = NULL;
4154 /* If sender_address is unqualified, reject it, unless this is a locally
4155 generated message, or the sending host or net is permitted to send
4156 unqualified addresses - typically local machines behaving as MUAs -
4157 in which case just qualify the address. The flag is set above at the start
4158 of the SMTP connection. */
4160 if (sender_domain == 0 && sender_address[0] != 0)
4162 if (allow_unqualified_sender)
4164 sender_domain = Ustrlen(sender_address) + 1;
4165 sender_address = rewrite_address_qualify(sender_address, FALSE);
4166 DEBUG(D_receive) debug_printf("unqualified address %s accepted\n",
4171 smtp_printf("501 %s: sender address must contain a domain\r\n",
4173 log_write(L_smtp_syntax_error,
4174 LOG_MAIN|LOG_REJECT,
4175 "unqualified sender rejected: <%s> %s%s",
4177 host_and_ident(TRUE),
4179 sender_address = NULL;
4184 /* Apply an ACL check if one is defined, before responding. Afterwards,
4185 when pipelining is not advertised, do another sync check in case the ACL
4186 delayed and the client started sending in the meantime. */
4190 rc = acl_check(ACL_WHERE_MAIL, NULL, acl_smtp_mail, &user_msg, &log_msg);
4191 if (rc == OK && !pipelining_advertised && !check_sync())
4197 if (rc == OK || rc == DISCARD)
4200 smtp_printf("%s%s%s", US"250 OK",
4201 #ifndef DISABLE_PRDR
4202 prdr_requested ? US", PRDR Requested" : US"",
4209 #ifndef DISABLE_PRDR
4211 user_msg = string_sprintf("%s%s", user_msg, US", PRDR Requested");
4213 smtp_user_msg(US"250", user_msg);
4215 smtp_delay_rcpt = smtp_rlr_base;
4216 recipients_discarded = (rc == DISCARD);
4217 was_rej_mail = FALSE;
4221 done = smtp_handle_acl_fail(ACL_WHERE_MAIL, rc, user_msg, log_msg);
4222 sender_address = NULL;
4227 /* The RCPT command requires an address as an operand. There may be any
4228 number of RCPT commands, specifying multiple recipients. We build them all
4229 into a data structure. The start/end values given by parse_extract_address
4230 are not used, as we keep only the extracted address. */
4235 was_rcpt = rcpt_in_progress = TRUE;
4237 /* There must be a sender address; if the sender was rejected and
4238 pipelining was advertised, we assume the client was pipelining, and do not
4239 count this as a protocol error. Reset was_rej_mail so that further RCPTs
4240 get the same treatment. */
4242 if (sender_address == NULL)
4244 if (pipelining_advertised && last_was_rej_mail)
4246 smtp_printf("503 sender not yet given\r\n");
4247 was_rej_mail = TRUE;
4251 done = synprot_error(L_smtp_protocol_error, 503, NULL,
4252 US"sender not yet given");
4253 was_rcpt = FALSE; /* Not a valid RCPT */
4259 /* Check for an operand */
4261 if (smtp_cmd_data[0] == 0)
4263 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4264 US"RCPT must have an address operand");
4269 /* Set the DSN flags orcpt and dsn_flags from the session*/
4275 uschar *name, *value;
4277 if (!extract_option(&name, &value))
4280 if (dsn_advertised && strcmpic(name, US"ORCPT") == 0)
4282 /* Check whether orcpt has been already set */
4285 synprot_error(L_smtp_syntax_error, 501, NULL,
4286 US"ORCPT can be specified once only");
4289 orcpt = string_copy(value);
4290 DEBUG(D_receive) debug_printf("DSN orcpt: %s\n", orcpt);
4293 else if (dsn_advertised && strcmpic(name, US"NOTIFY") == 0)
4295 /* Check if the notify flags have been already set */
4298 synprot_error(L_smtp_syntax_error, 501, NULL,
4299 US"NOTIFY can be specified once only");
4302 if (strcmpic(value, US"NEVER") == 0)
4303 flags |= rf_notify_never;
4310 while (*pp != 0 && *pp != ',') pp++;
4311 if (*pp == ',') *pp++ = 0;
4312 if (strcmpic(p, US"SUCCESS") == 0)
4314 DEBUG(D_receive) debug_printf("DSN: Setting notify success\n");
4315 flags |= rf_notify_success;
4317 else if (strcmpic(p, US"FAILURE") == 0)
4319 DEBUG(D_receive) debug_printf("DSN: Setting notify failure\n");
4320 flags |= rf_notify_failure;
4322 else if (strcmpic(p, US"DELAY") == 0)
4324 DEBUG(D_receive) debug_printf("DSN: Setting notify delay\n");
4325 flags |= rf_notify_delay;
4329 /* Catch any strange values */
4330 synprot_error(L_smtp_syntax_error, 501, NULL,
4331 US"Invalid value for NOTIFY parameter");
4336 DEBUG(D_receive) debug_printf("DSN Flags: %x\n", flags);
4340 /* Unknown option. Stick back the terminator characters and break
4341 the loop. An error for a malformed address will occur. */
4345 DEBUG(D_receive) debug_printf("Invalid RCPT option: %s : %s\n", name, value);
4352 /* Apply SMTP rewriting then extract the working address. Don't allow "<>"
4353 as a recipient address */
4355 recipient = ((rewrite_existflags & rewrite_smtp) != 0)?
4356 rewrite_one(smtp_cmd_data, rewrite_smtp, NULL, FALSE, US"",
4357 global_rewrite_rules) : smtp_cmd_data;
4359 /* rfc821_domains = TRUE; << no longer needed */
4360 recipient = parse_extract_address(recipient, &errmess, &start, &end,
4361 &recipient_domain, FALSE);
4362 /* rfc821_domains = FALSE; << no longer needed */
4364 if (recipient == NULL)
4366 done = synprot_error(L_smtp_syntax_error, 501, smtp_cmd_data, errmess);
4371 /* If the recipient address is unqualified, reject it, unless this is a
4372 locally generated message. However, unqualified addresses are permitted
4373 from a configured list of hosts and nets - typically when behaving as
4374 MUAs rather than MTAs. Sad that SMTP is used for both types of traffic,
4375 really. The flag is set at the start of the SMTP connection.
4377 RFC 1123 talks about supporting "the reserved mailbox postmaster"; I always
4378 assumed this meant "reserved local part", but the revision of RFC 821 and
4379 friends now makes it absolutely clear that it means *mailbox*. Consequently
4380 we must always qualify this address, regardless. */
4382 if (recipient_domain == 0)
4384 if (allow_unqualified_recipient ||
4385 strcmpic(recipient, US"postmaster") == 0)
4387 DEBUG(D_receive) debug_printf("unqualified address %s accepted\n",
4389 recipient_domain = Ustrlen(recipient) + 1;
4390 recipient = rewrite_address_qualify(recipient, TRUE);
4395 smtp_printf("501 %s: recipient address must contain a domain\r\n",
4397 log_write(L_smtp_syntax_error,
4398 LOG_MAIN|LOG_REJECT, "unqualified recipient rejected: "
4399 "<%s> %s%s", recipient, host_and_ident(TRUE),
4405 /* Check maximum allowed */
4407 if (rcpt_count > recipients_max && recipients_max > 0)
4409 if (recipients_max_reject)
4412 smtp_printf("552 too many recipients\r\n");
4414 log_write(0, LOG_MAIN|LOG_REJECT, "too many recipients: message "
4415 "rejected: sender=<%s> %s", sender_address, host_and_ident(TRUE));
4420 smtp_printf("452 too many recipients\r\n");
4422 log_write(0, LOG_MAIN|LOG_REJECT, "too many recipients: excess "
4423 "temporarily rejected: sender=<%s> %s", sender_address,
4424 host_and_ident(TRUE));
4431 /* If we have passed the threshold for rate limiting, apply the current
4432 delay, and update it for next time, provided this is a limited host. */
4434 if (rcpt_count > smtp_rlr_threshold &&
4435 verify_check_host(&smtp_ratelimit_hosts) == OK)
4437 DEBUG(D_receive) debug_printf("rate limit RCPT: delay %.3g sec\n",
4438 smtp_delay_rcpt/1000.0);
4439 millisleep((int)smtp_delay_rcpt);
4440 smtp_delay_rcpt *= smtp_rlr_factor;
4441 if (smtp_delay_rcpt > (double)smtp_rlr_limit)
4442 smtp_delay_rcpt = (double)smtp_rlr_limit;
4445 /* If the MAIL ACL discarded all the recipients, we bypass ACL checking
4446 for them. Otherwise, check the access control list for this recipient. As
4447 there may be a delay in this, re-check for a synchronization error
4448 afterwards, unless pipelining was advertised. */
4450 if (recipients_discarded) rc = DISCARD; else
4452 rc = acl_check(ACL_WHERE_RCPT, recipient, acl_smtp_rcpt, &user_msg,
4454 if (rc == OK && !pipelining_advertised && !check_sync())
4458 /* The ACL was happy */
4462 if (user_msg == NULL) smtp_printf("250 Accepted\r\n");
4463 else smtp_user_msg(US"250", user_msg);
4464 receive_add_recipient(recipient, -1);
4466 /* Set the dsn flags in the recipients_list */
4467 recipients_list[recipients_count-1].orcpt = orcpt;
4468 recipients_list[recipients_count-1].dsn_flags = flags;
4470 DEBUG(D_receive) debug_printf("DSN: orcpt: %s flags: %d\n",
4471 recipients_list[recipients_count-1].orcpt,
4472 recipients_list[recipients_count-1].dsn_flags);
4475 /* The recipient was discarded */
4477 else if (rc == DISCARD)
4479 if (user_msg == NULL) smtp_printf("250 Accepted\r\n");
4480 else smtp_user_msg(US"250", user_msg);
4483 log_write(0, LOG_MAIN|LOG_REJECT, "%s F=<%s> RCPT %s: "
4484 "discarded by %s ACL%s%s", host_and_ident(TRUE),
4485 sender_address_unrewritten? sender_address_unrewritten : sender_address,
4486 smtp_cmd_argument, recipients_discarded? "MAIL" : "RCPT",
4487 log_msg ? US": " : US"", log_msg ? log_msg : US"");
4490 /* Either the ACL failed the address, or it was deferred. */
4494 if (rc == FAIL) rcpt_fail_count++; else rcpt_defer_count++;
4495 done = smtp_handle_acl_fail(ACL_WHERE_RCPT, rc, user_msg, log_msg);
4500 /* The DATA command is legal only if it follows successful MAIL FROM
4501 and RCPT TO commands. However, if pipelining is advertised, a bad DATA is
4502 not counted as a protocol error if it follows RCPT (which must have been
4503 rejected if there are no recipients.) This function is complete when a
4504 valid DATA command is encountered.
4506 Note concerning the code used: RFC 2821 says this:
4508 - If there was no MAIL, or no RCPT, command, or all such commands
4509 were rejected, the server MAY return a "command out of sequence"
4510 (503) or "no valid recipients" (554) reply in response to the
4513 The example in the pipelining RFC 2920 uses 554, but I use 503 here
4514 because it is the same whether pipelining is in use or not.
4516 If all the RCPT commands that precede DATA provoked the same error message
4517 (often indicating some kind of system error), it is helpful to include it
4518 with the DATA rejection (an idea suggested by Tony Finch). */
4522 if (!discarded && recipients_count <= 0)
4524 if (rcpt_smtp_response_same && rcpt_smtp_response != NULL)
4526 uschar *code = US"503";
4527 int len = Ustrlen(rcpt_smtp_response);
4528 smtp_respond(code, 3, FALSE, US"All RCPT commands were rejected with "
4530 /* Responses from smtp_printf() will have \r\n on the end */
4531 if (len > 2 && rcpt_smtp_response[len-2] == '\r')
4532 rcpt_smtp_response[len-2] = 0;
4533 smtp_respond(code, 3, FALSE, rcpt_smtp_response);
4535 if (pipelining_advertised && last_was_rcpt)
4536 smtp_printf("503 Valid RCPT command must precede DATA\r\n");
4538 done = synprot_error(L_smtp_protocol_error, 503, NULL,
4539 US"valid RCPT command must precede DATA");
4543 if (toomany && recipients_max_reject)
4545 sender_address = NULL; /* This will allow a new MAIL without RSET */
4546 sender_address_unrewritten = NULL;
4547 smtp_printf("554 Too many recipients\r\n");
4551 /* If there is an ACL, re-check the synchronization afterwards, since the
4552 ACL may have delayed. To handle cutthrough delivery enforce a dummy call
4553 to get the DATA command sent. */
4555 if (acl_smtp_predata == NULL && cutthrough.fd < 0) rc = OK; else
4557 uschar * acl= acl_smtp_predata ? acl_smtp_predata : US"accept";
4558 enable_dollar_recipients = TRUE;
4559 rc = acl_check(ACL_WHERE_PREDATA, NULL, acl, &user_msg,
4561 enable_dollar_recipients = FALSE;
4562 if (rc == OK && !check_sync()) goto SYNC_FAILURE;
4569 if (user_msg == NULL)
4570 smtp_printf("%s Enter message, ending with \".\" on a line by itself\r\n", code);
4571 else smtp_user_msg(code, user_msg);
4573 message_ended = END_NOTENDED; /* Indicate in middle of data */
4576 /* Either the ACL failed the address, or it was deferred. */
4579 done = smtp_handle_acl_fail(ACL_WHERE_PREDATA, rc, user_msg, log_msg);
4585 rc = acl_check(ACL_WHERE_VRFY, NULL, acl_smtp_vrfy, &user_msg, &log_msg);
4587 done = smtp_handle_acl_fail(ACL_WHERE_VRFY, rc, user_msg, log_msg);
4593 /* rfc821_domains = TRUE; << no longer needed */
4594 address = parse_extract_address(smtp_cmd_data, &errmess, &start, &end,
4595 &recipient_domain, FALSE);
4596 /* rfc821_domains = FALSE; << no longer needed */
4598 if (address == NULL)
4599 s = string_sprintf("501 %s", errmess);
4602 address_item *addr = deliver_make_addr(address, FALSE);
4603 switch(verify_address(addr, NULL, vopt_is_recipient | vopt_qualify, -1,
4604 -1, -1, NULL, NULL, NULL))
4607 s = string_sprintf("250 <%s> is deliverable", address);
4611 s = (addr->user_message != NULL)?
4612 string_sprintf("451 <%s> %s", address, addr->user_message) :
4613 string_sprintf("451 Cannot resolve <%s> at this time", address);
4617 s = (addr->user_message != NULL)?
4618 string_sprintf("550 <%s> %s", address, addr->user_message) :
4619 string_sprintf("550 <%s> is not deliverable", address);
4620 log_write(0, LOG_MAIN, "VRFY failed for %s %s",
4621 smtp_cmd_argument, host_and_ident(TRUE));
4626 smtp_printf("%s\r\n", s);
4633 rc = acl_check(ACL_WHERE_EXPN, NULL, acl_smtp_expn, &user_msg, &log_msg);
4635 done = smtp_handle_acl_fail(ACL_WHERE_EXPN, rc, user_msg, log_msg);
4638 BOOL save_log_testing_mode = log_testing_mode;
4639 address_test_mode = log_testing_mode = TRUE;
4640 (void) verify_address(deliver_make_addr(smtp_cmd_data, FALSE),
4641 smtp_out, vopt_is_recipient | vopt_qualify | vopt_expn, -1, -1, -1,
4643 address_test_mode = FALSE;
4644 log_testing_mode = save_log_testing_mode; /* true for -bh */
4653 if (!tls_advertised)
4655 done = synprot_error(L_smtp_protocol_error, 503, NULL,
4656 US"STARTTLS command used when not advertised");
4660 /* Apply an ACL check if one is defined */
4662 if (acl_smtp_starttls != NULL)
4664 rc = acl_check(ACL_WHERE_STARTTLS, NULL, acl_smtp_starttls, &user_msg,
4668 done = smtp_handle_acl_fail(ACL_WHERE_STARTTLS, rc, user_msg, log_msg);
4673 /* RFC 2487 is not clear on when this command may be sent, though it
4674 does state that all information previously obtained from the client
4675 must be discarded if a TLS session is started. It seems reasonble to
4676 do an implied RSET when STARTTLS is received. */
4678 incomplete_transaction_log(US"STARTTLS");
4679 smtp_reset(reset_point);
4681 cmd_list[CMD_LIST_STARTTLS].is_mail_cmd = FALSE;
4683 /* There's an attack where more data is read in past the STARTTLS command
4684 before TLS is negotiated, then assumed to be part of the secure session
4685 when used afterwards; we use segregated input buffers, so are not
4686 vulnerable, but we want to note when it happens and, for sheer paranoia,
4687 ensure that the buffer is "wiped".
4688 Pipelining sync checks will normally have protected us too, unless disabled
4689 by configuration. */
4691 if (receive_smtp_buffered())
4694 debug_printf("Non-empty input buffer after STARTTLS; naive attack?");
4695 if (tls_in.active < 0)
4696 smtp_inend = smtp_inptr = smtp_inbuffer;
4697 /* and if TLS is already active, tls_server_start() should fail */
4700 /* There is nothing we value in the input buffer and if TLS is succesfully
4701 negotiated, we won't use this buffer again; if TLS fails, we'll just read
4702 fresh content into it. The buffer contains arbitrary content from an
4703 untrusted remote source; eg: NOOP <shellcode>\r\nSTARTTLS\r\n
4704 It seems safest to just wipe away the content rather than leave it as a
4705 target to jump to. */
4707 memset(smtp_inbuffer, 0, in_buffer_size);
4709 /* Attempt to start up a TLS session, and if successful, discard all
4710 knowledge that was obtained previously. At least, that's what the RFC says,
4711 and that's what happens by default. However, in order to work round YAEB,
4712 there is an option to remember the esmtp state. Sigh.
4714 We must allow for an extra EHLO command and an extra AUTH command after
4715 STARTTLS that don't add to the nonmail command count. */
4717 if ((rc = tls_server_start(tls_require_ciphers)) == OK)
4719 if (!tls_remember_esmtp)
4720 helo_seen = esmtp = auth_advertised = pipelining_advertised = FALSE;
4721 cmd_list[CMD_LIST_EHLO].is_mail_cmd = TRUE;
4722 cmd_list[CMD_LIST_AUTH].is_mail_cmd = TRUE;
4723 cmd_list[CMD_LIST_TLS_AUTH].is_mail_cmd = TRUE;
4724 if (sender_helo_name != NULL)
4726 store_free(sender_helo_name);
4727 sender_helo_name = NULL;
4728 host_build_sender_fullhost(); /* Rebuild */
4729 set_process_info("handling incoming TLS connection from %s",
4730 host_and_ident(FALSE));
4733 (sender_host_address ? protocols : protocols_local)
4735 ? pextend + (sender_host_authenticated ? pauthed : 0)
4737 + (tls_in.active >= 0 ? pcrpted : 0)
4740 sender_host_authenticated = NULL;
4741 authenticated_id = NULL;
4742 sync_cmd_limit = NON_SYNC_CMD_NON_PIPELINING;
4743 DEBUG(D_tls) debug_printf("TLS active\n");
4744 break; /* Successful STARTTLS */
4747 /* Some local configuration problem was discovered before actually trying
4748 to do a TLS handshake; give a temporary error. */
4750 else if (rc == DEFER)
4752 smtp_printf("454 TLS currently unavailable\r\n");
4756 /* Hard failure. Reject everything except QUIT or closed connection. One
4757 cause for failure is a nested STARTTLS, in which case tls_in.active remains
4758 set, but we must still reject all incoming commands. */
4760 DEBUG(D_tls) debug_printf("TLS failed to start\n");
4763 switch(smtp_read_command(FALSE))
4766 log_write(L_smtp_connection, LOG_MAIN, "%s closed by EOF",
4767 smtp_get_connection_info());
4768 smtp_notquit_exit(US"tls-failed", NULL, NULL);
4772 /* It is perhaps arguable as to which exit ACL should be called here,
4773 but as it is probably a situation that almost never arises, it
4774 probably doesn't matter. We choose to call the real QUIT ACL, which in
4775 some sense is perhaps "right". */
4779 if (acl_smtp_quit != NULL)
4781 rc = acl_check(ACL_WHERE_QUIT, NULL, acl_smtp_quit, &user_msg,
4784 log_write(0, LOG_MAIN|LOG_PANIC, "ACL for QUIT returned ERROR: %s",
4787 if (user_msg == NULL)
4788 smtp_printf("221 %s closing connection\r\n", smtp_active_hostname);
4790 smtp_respond(US"221", 3, TRUE, user_msg);
4791 log_write(L_smtp_connection, LOG_MAIN, "%s closed by QUIT",
4792 smtp_get_connection_info());
4797 smtp_printf("554 Security failure\r\n");
4801 tls_close(TRUE, TRUE);
4806 /* The ACL for QUIT is provided for gathering statistical information or
4807 similar; it does not affect the response code, but it can supply a custom
4812 incomplete_transaction_log(US"QUIT");
4813 if (acl_smtp_quit != NULL)
4815 rc = acl_check(ACL_WHERE_QUIT, NULL, acl_smtp_quit, &user_msg, &log_msg);
4817 log_write(0, LOG_MAIN|LOG_PANIC, "ACL for QUIT returned ERROR: %s",
4820 if (user_msg == NULL)
4821 smtp_printf("221 %s closing connection\r\n", smtp_active_hostname);
4823 smtp_respond(US"221", 3, TRUE, user_msg);
4826 tls_close(TRUE, TRUE);
4830 log_write(L_smtp_connection, LOG_MAIN, "%s closed by QUIT",
4831 smtp_get_connection_info());
4837 incomplete_transaction_log(US"RSET");
4838 smtp_reset(reset_point);
4840 smtp_printf("250 Reset OK\r\n");
4841 cmd_list[CMD_LIST_RSET].is_mail_cmd = FALSE;
4847 smtp_printf("250 OK\r\n");
4851 /* Show ETRN/EXPN/VRFY if there's an ACL for checking hosts; if actually
4852 used, a check will be done for permitted hosts. Show STARTTLS only if not
4853 already in a TLS session and if it would be advertised in the EHLO
4858 smtp_printf("214-Commands supported:\r\n");
4862 Ustrcat(buffer, " AUTH");
4864 if (tls_in.active < 0 &&
4865 verify_check_host(&tls_advertise_hosts) != FAIL)
4866 Ustrcat(buffer, " STARTTLS");
4868 Ustrcat(buffer, " HELO EHLO MAIL RCPT DATA");
4869 Ustrcat(buffer, " NOOP QUIT RSET HELP");
4870 if (acl_smtp_etrn != NULL) Ustrcat(buffer, " ETRN");
4871 if (acl_smtp_expn != NULL) Ustrcat(buffer, " EXPN");
4872 if (acl_smtp_vrfy != NULL) Ustrcat(buffer, " VRFY");
4873 smtp_printf("214%s\r\n", buffer);
4879 incomplete_transaction_log(US"connection lost");
4880 smtp_notquit_exit(US"connection-lost", US"421",
4881 US"%s lost input connection", smtp_active_hostname);
4883 /* Don't log by default unless in the middle of a message, as some mailers
4884 just drop the call rather than sending QUIT, and it clutters up the logs.
4887 if (sender_address != NULL || recipients_count > 0)
4888 log_write(L_lost_incoming_connection,
4890 "unexpected %s while reading SMTP command from %s%s",
4891 sender_host_unknown? "EOF" : "disconnection",
4892 host_and_ident(FALSE), smtp_read_error);
4894 else log_write(L_smtp_connection, LOG_MAIN, "%s lost%s",
4895 smtp_get_connection_info(), smtp_read_error);
4903 if (sender_address != NULL)
4905 done = synprot_error(L_smtp_protocol_error, 503, NULL,
4906 US"ETRN is not permitted inside a transaction");
4910 log_write(L_etrn, LOG_MAIN, "ETRN %s received from %s", smtp_cmd_argument,
4911 host_and_ident(FALSE));
4913 rc = acl_check(ACL_WHERE_ETRN, NULL, acl_smtp_etrn, &user_msg, &log_msg);
4916 done = smtp_handle_acl_fail(ACL_WHERE_ETRN, rc, user_msg, log_msg);
4920 /* Compute the serialization key for this command. */
4922 etrn_serialize_key = string_sprintf("etrn-%s\n", smtp_cmd_data);
4924 /* If a command has been specified for running as a result of ETRN, we
4925 permit any argument to ETRN. If not, only the # standard form is permitted,
4926 since that is strictly the only kind of ETRN that can be implemented
4927 according to the RFC. */
4929 if (smtp_etrn_command != NULL)
4933 etrn_command = smtp_etrn_command;
4934 deliver_domain = smtp_cmd_data;
4935 rc = transport_set_up_command(&argv, smtp_etrn_command, TRUE, 0, NULL,
4936 US"ETRN processing", &error);
4937 deliver_domain = NULL;
4940 log_write(0, LOG_MAIN|LOG_PANIC, "failed to set up ETRN command: %s",
4942 smtp_printf("458 Internal failure\r\n");
4947 /* Else set up to call Exim with the -R option. */
4951 if (*smtp_cmd_data++ != '#')
4953 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4954 US"argument must begin with #");
4957 etrn_command = US"exim -R";
4958 argv = CUSS child_exec_exim(CEE_RETURN_ARGV, TRUE, NULL, TRUE, 2, US"-R",
4962 /* If we are host-testing, don't actually do anything. */
4968 debug_printf("ETRN command is: %s\n", etrn_command);
4969 debug_printf("ETRN command execution skipped\n");
4971 if (user_msg == NULL) smtp_printf("250 OK\r\n");
4972 else smtp_user_msg(US"250", user_msg);
4977 /* If ETRN queue runs are to be serialized, check the database to
4978 ensure one isn't already running. */
4980 if (smtp_etrn_serialize && !enq_start(etrn_serialize_key, 1))
4982 smtp_printf("458 Already processing %s\r\n", smtp_cmd_data);
4986 /* Fork a child process and run the command. We don't want to have to
4987 wait for the process at any point, so set SIGCHLD to SIG_IGN before
4988 forking. It should be set that way anyway for external incoming SMTP,
4989 but we save and restore to be tidy. If serialization is required, we
4990 actually run the command in yet another process, so we can wait for it
4991 to complete and then remove the serialization lock. */
4993 oldsignal = signal(SIGCHLD, SIG_IGN);
4995 if ((pid = fork()) == 0)
4997 smtp_input = FALSE; /* This process is not associated with the */
4998 (void)fclose(smtp_in); /* SMTP call any more. */
4999 (void)fclose(smtp_out);
5001 signal(SIGCHLD, SIG_DFL); /* Want to catch child */
5003 /* If not serializing, do the exec right away. Otherwise, fork down
5004 into another process. */
5006 if (!smtp_etrn_serialize || (pid = fork()) == 0)
5008 DEBUG(D_exec) debug_print_argv(argv);
5009 exim_nullstd(); /* Ensure std{in,out,err} exist */
5010 execv(CS argv[0], (char *const *)argv);
5011 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "exec of \"%s\" (ETRN) failed: %s",
5012 etrn_command, strerror(errno));
5013 _exit(EXIT_FAILURE); /* paranoia */
5016 /* Obey this if smtp_serialize and the 2nd fork yielded non-zero. That
5017 is, we are in the first subprocess, after forking again. All we can do
5018 for a failing fork is to log it. Otherwise, wait for the 2nd process to
5019 complete, before removing the serialization. */
5022 log_write(0, LOG_MAIN|LOG_PANIC, "2nd fork for serialized ETRN "
5023 "failed: %s", strerror(errno));
5027 DEBUG(D_any) debug_printf("waiting for serialized ETRN process %d\n",
5029 (void)wait(&status);
5030 DEBUG(D_any) debug_printf("serialized ETRN process %d ended\n",
5034 enq_end(etrn_serialize_key);
5035 _exit(EXIT_SUCCESS);
5038 /* Back in the top level SMTP process. Check that we started a subprocess
5039 and restore the signal state. */
5043 log_write(0, LOG_MAIN|LOG_PANIC, "fork of process for ETRN failed: %s",
5045 smtp_printf("458 Unable to fork process\r\n");
5046 if (smtp_etrn_serialize) enq_end(etrn_serialize_key);
5050 if (user_msg == NULL) smtp_printf("250 OK\r\n");
5051 else smtp_user_msg(US"250", user_msg);
5054 signal(SIGCHLD, oldsignal);
5059 done = synprot_error(L_smtp_syntax_error, 501, NULL,
5060 US"unexpected argument data");
5064 /* This currently happens only for NULLs, but could be extended. */
5067 done = synprot_error(L_smtp_syntax_error, 0, NULL, /* Just logs */
5068 US"NULL character(s) present (shown as '?')");
5069 smtp_printf("501 NULL characters are not allowed in SMTP commands\r\n");
5075 if (smtp_inend >= smtp_inbuffer + in_buffer_size)
5076 smtp_inend = smtp_inbuffer + in_buffer_size - 1;
5077 c = smtp_inend - smtp_inptr;
5078 if (c > 150) c = 150;
5080 incomplete_transaction_log(US"sync failure");
5081 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP protocol synchronization error "
5082 "(next input sent too soon: pipelining was%s advertised): "
5083 "rejected \"%s\" %s next input=\"%s\"",
5084 pipelining_advertised? "" : " not",
5085 smtp_cmd_buffer, host_and_ident(TRUE),
5086 string_printing(smtp_inptr));
5087 smtp_notquit_exit(US"synchronization-error", US"554",
5088 US"SMTP synchronization error");
5089 done = 1; /* Pretend eof - drops connection */
5093 case TOO_MANY_NONMAIL_CMD:
5094 s = smtp_cmd_buffer;
5095 while (*s != 0 && !isspace(*s)) s++;
5096 incomplete_transaction_log(US"too many non-mail commands");
5097 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
5098 "nonmail commands (last was \"%.*s\")", host_and_ident(FALSE),
5099 (int)(s - smtp_cmd_buffer), smtp_cmd_buffer);
5100 smtp_notquit_exit(US"bad-commands", US"554", US"Too many nonmail commands");
5101 done = 1; /* Pretend eof - drops connection */
5104 #ifdef SUPPORT_PROXY
5105 case PROXY_FAIL_IGNORE_CMD:
5106 smtp_printf("503 Command refused, required Proxy negotiation failed\r\n");
5111 if (unknown_command_count++ >= smtp_max_unknown_commands)
5113 log_write(L_smtp_syntax_error, LOG_MAIN,
5114 "SMTP syntax error in \"%s\" %s %s",
5115 string_printing(smtp_cmd_buffer), host_and_ident(TRUE),
5116 US"unrecognized command");
5117 incomplete_transaction_log(US"unrecognized command");
5118 smtp_notquit_exit(US"bad-commands", US"500",
5119 US"Too many unrecognized commands");
5121 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
5122 "unrecognized commands (last was \"%s\")", host_and_ident(FALSE),
5123 string_printing(smtp_cmd_buffer));
5126 done = synprot_error(L_smtp_syntax_error, 500, NULL,
5127 US"unrecognized command");
5131 /* This label is used by goto's inside loops that want to break out to
5132 the end of the command-processing loop. */
5135 last_was_rej_mail = was_rej_mail; /* Remember some last commands for */
5136 last_was_rcpt = was_rcpt; /* protocol error handling */
5140 return done - 2; /* Convert yield values */
5145 /* End of smtp_in.c */