1 /*************************************************
2 * Exim - an Internet mail transport agent *
3 *************************************************/
5 /* Copyright (c) University of Cambridge 1995 - 2014 */
6 /* See the file NOTICE for conditions of use and distribution. */
8 /* Functions for handling an incoming SMTP call. */
14 /* Initialize for TCP wrappers if so configured. It appears that the macro
15 HAVE_IPV6 is used in some versions of the tcpd.h header, so we unset it before
16 including that header, and restore its value afterwards. */
18 #ifdef USE_TCP_WRAPPERS
21 #define EXIM_HAVE_IPV6
27 #define HAVE_IPV6 TRUE
30 int allow_severity = LOG_INFO;
31 int deny_severity = LOG_NOTICE;
32 uschar *tcp_wrappers_name;
36 /* Size of buffer for reading SMTP commands. We used to use 512, as defined
37 by RFC 821. However, RFC 1869 specifies that this must be increased for SMTP
38 commands that accept arguments, and this in particular applies to AUTH, where
39 the data can be quite long. More recently this value was 2048 in Exim;
40 however, RFC 4954 (circa 2007) recommends 12288 bytes to handle AUTH. Clients
41 such as Thunderbird will send an AUTH with an initial-response for GSSAPI.
42 The maximum size of a Kerberos ticket under Windows 2003 is 12000 bytes, and
43 we need room to handle large base64-encoded AUTHs for GSSAPI.
46 #define smtp_cmd_buffer_size 16384
48 /* Size of buffer for reading SMTP incoming packets */
50 #define in_buffer_size 8192
52 /* Structure for SMTP command list */
59 short int is_mail_cmd;
62 /* Codes for identifying commands. We order them so that those that come first
63 are those for which synchronization is always required. Checking this can help
67 /* These commands are required to be synchronized, i.e. to be the last in a
68 block of commands when pipelining. */
70 HELO_CMD, EHLO_CMD, DATA_CMD, /* These are listed in the pipelining */
71 VRFY_CMD, EXPN_CMD, NOOP_CMD, /* RFC as requiring synchronization */
72 ETRN_CMD, /* This by analogy with TURN from the RFC */
73 STARTTLS_CMD, /* Required by the STARTTLS RFC */
75 /* This is a dummy to identify the non-sync commands when pipelining */
77 NON_SYNC_CMD_PIPELINING,
79 /* These commands need not be synchronized when pipelining */
81 MAIL_CMD, RCPT_CMD, RSET_CMD,
83 /* This is a dummy to identify the non-sync commands when not pipelining */
85 NON_SYNC_CMD_NON_PIPELINING,
87 /* I have been unable to find a statement about the use of pipelining
88 with AUTH, so to be on the safe side it is here, though I kind of feel
89 it should be up there with the synchronized commands. */
93 /* I'm not sure about these, but I don't think they matter. */
97 #ifdef EXPERIMENTAL_PROXY
98 PROXY_FAIL_IGNORE_CMD,
101 /* These are specials that don't correspond to actual commands */
103 EOF_CMD, OTHER_CMD, BADARG_CMD, BADCHAR_CMD, BADSYN_CMD,
104 TOO_MANY_NONMAIL_CMD };
107 /* This is a convenience macro for adding the identity of an SMTP command
108 to the circular buffer that holds a list of the last n received. */
111 smtp_connection_had[smtp_ch_index++] = n; \
112 if (smtp_ch_index >= SMTP_HBUFF_SIZE) smtp_ch_index = 0
115 /*************************************************
116 * Local static variables *
117 *************************************************/
119 static auth_instance *authenticated_by;
120 static BOOL auth_advertised;
122 static BOOL tls_advertised;
124 #ifdef EXPERIMENTAL_DSN
125 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;
138 static int synprot_error_count;
139 static int unknown_command_count;
140 static int sync_cmd_limit;
141 static int smtp_write_error = 0;
143 static uschar *rcpt_smtp_response;
144 static uschar *smtp_data_buffer;
145 static uschar *smtp_cmd_data;
147 /* We need to know the position of RSET, HELO, EHLO, AUTH, and STARTTLS. Their
148 final fields of all except AUTH are forced TRUE at the start of a new message
149 setup, to allow one of each between messages that is not counted as a nonmail
150 command. (In fact, only one of HELO/EHLO is not counted.) Also, we have to
151 allow a new EHLO after starting up TLS.
153 AUTH is "falsely" labelled as a mail command initially, so that it doesn't get
154 counted. However, the flag is changed when AUTH is received, so that multiple
155 failing AUTHs will eventually hit the limit. After a successful AUTH, another
156 AUTH is already forbidden. After a TLS session is started, AUTH's flag is again
157 forced TRUE, to allow for the re-authentication that can happen at that point.
159 QUIT is also "falsely" labelled as a mail command so that it doesn't up the
160 count of non-mail commands and possibly provoke an error. */
162 static smtp_cmd_list cmd_list[] = {
163 { "rset", sizeof("rset")-1, RSET_CMD, FALSE, FALSE }, /* First */
164 { "helo", sizeof("helo")-1, HELO_CMD, TRUE, FALSE },
165 { "ehlo", sizeof("ehlo")-1, EHLO_CMD, TRUE, FALSE },
166 { "auth", sizeof("auth")-1, AUTH_CMD, TRUE, TRUE },
168 { "starttls", sizeof("starttls")-1, STARTTLS_CMD, FALSE, FALSE },
171 /* If you change anything above here, also fix the definitions below. */
173 { "mail from:", sizeof("mail from:")-1, MAIL_CMD, TRUE, TRUE },
174 { "rcpt to:", sizeof("rcpt to:")-1, RCPT_CMD, TRUE, TRUE },
175 { "data", sizeof("data")-1, DATA_CMD, FALSE, TRUE },
176 { "quit", sizeof("quit")-1, QUIT_CMD, FALSE, TRUE },
177 { "noop", sizeof("noop")-1, NOOP_CMD, TRUE, FALSE },
178 { "etrn", sizeof("etrn")-1, ETRN_CMD, TRUE, FALSE },
179 { "vrfy", sizeof("vrfy")-1, VRFY_CMD, TRUE, FALSE },
180 { "expn", sizeof("expn")-1, EXPN_CMD, TRUE, FALSE },
181 { "help", sizeof("help")-1, HELP_CMD, TRUE, FALSE }
184 static smtp_cmd_list *cmd_list_end =
185 cmd_list + sizeof(cmd_list)/sizeof(smtp_cmd_list);
187 #define CMD_LIST_RSET 0
188 #define CMD_LIST_HELO 1
189 #define CMD_LIST_EHLO 2
190 #define CMD_LIST_AUTH 3
191 #define CMD_LIST_STARTTLS 4
193 /* This list of names is used for performing the smtp_no_mail logging action.
194 It must be kept in step with the SCH_xxx enumerations. */
196 static uschar *smtp_names[] =
198 US"NONE", US"AUTH", US"DATA", US"EHLO", US"ETRN", US"EXPN", US"HELO",
199 US"HELP", US"MAIL", US"NOOP", US"QUIT", US"RCPT", US"RSET", US"STARTTLS",
202 static uschar *protocols[] = {
203 US"local-smtp", /* HELO */
204 US"local-smtps", /* The rare case EHLO->STARTTLS->HELO */
205 US"local-esmtp", /* EHLO */
206 US"local-esmtps", /* EHLO->STARTTLS->EHLO */
207 US"local-esmtpa", /* EHLO->AUTH */
208 US"local-esmtpsa" /* EHLO->STARTTLS->EHLO->AUTH */
213 #define pcrpted 1 /* added to pextend or pnormal */
214 #define pauthed 2 /* added to pextend */
215 #define pnlocal 6 /* offset to remove "local" */
217 /* Sanity check and validate optional args to MAIL FROM: envelope */
219 ENV_MAIL_OPT_SIZE, ENV_MAIL_OPT_BODY, ENV_MAIL_OPT_AUTH,
223 #ifdef EXPERIMENTAL_DSN
224 ENV_MAIL_OPT_RET, ENV_MAIL_OPT_ENVID,
229 uschar * name; /* option requested during MAIL cmd */
230 int value; /* enum type */
231 BOOL need_value; /* TRUE requires value (name=value pair format)
232 FALSE is a singleton */
234 static env_mail_type_t env_mail_type_list[] = {
235 { US"SIZE", ENV_MAIL_OPT_SIZE, TRUE },
236 { US"BODY", ENV_MAIL_OPT_BODY, TRUE },
237 { US"AUTH", ENV_MAIL_OPT_AUTH, TRUE },
239 { US"PRDR", ENV_MAIL_OPT_PRDR, FALSE },
241 #ifdef EXPERIMENTAL_DSN
242 { US"RET", ENV_MAIL_OPT_RET, TRUE },
243 { US"ENVID", ENV_MAIL_OPT_ENVID, TRUE },
245 { US"NULL", ENV_MAIL_OPT_NULL, FALSE }
248 /* When reading SMTP from a remote host, we have to use our own versions of the
249 C input-reading functions, in order to be able to flush the SMTP output only
250 when about to read more data from the socket. This is the only way to get
251 optimal performance when the client is using pipelining. Flushing for every
252 command causes a separate packet and reply packet each time; saving all the
253 responses up (when pipelining) combines them into one packet and one response.
255 For simplicity, these functions are used for *all* SMTP input, not only when
256 receiving over a socket. However, after setting up a secure socket (SSL), input
257 is read via the OpenSSL library, and another set of functions is used instead
260 These functions are set in the receive_getc etc. variables and called with the
261 same interface as the C functions. However, since there can only ever be
262 one incoming SMTP call, we just use a single buffer and flags. There is no need
263 to implement a complicated private FILE-like structure.*/
265 static uschar *smtp_inbuffer;
266 static uschar *smtp_inptr;
267 static uschar *smtp_inend;
268 static int smtp_had_eof;
269 static int smtp_had_error;
272 /*************************************************
273 * SMTP version of getc() *
274 *************************************************/
276 /* This gets the next byte from the SMTP input buffer. If the buffer is empty,
277 it flushes the output, and refills the buffer, with a timeout. The signal
278 handler is set appropriately by the calling function. This function is not used
279 after a connection has negotated itself into an TLS/SSL state.
282 Returns: the next character or EOF
288 if (smtp_inptr >= smtp_inend)
292 if (smtp_receive_timeout > 0) alarm(smtp_receive_timeout);
293 rc = read(fileno(smtp_in), smtp_inbuffer, in_buffer_size);
298 /* Must put the error text in fixed store, because this might be during
299 header reading, where it releases unused store above the header. */
302 smtp_had_error = save_errno;
303 smtp_read_error = string_copy_malloc(
304 string_sprintf(" (error: %s)", strerror(save_errno)));
306 else smtp_had_eof = 1;
310 dkim_exim_verify_feed(smtp_inbuffer, rc);
312 smtp_inend = smtp_inbuffer + rc;
313 smtp_inptr = smtp_inbuffer;
315 return *smtp_inptr++;
320 /*************************************************
321 * SMTP version of ungetc() *
322 *************************************************/
324 /* Puts a character back in the input buffer. Only ever
330 Returns: the character
336 *(--smtp_inptr) = ch;
343 /*************************************************
344 * SMTP version of feof() *
345 *************************************************/
347 /* Tests for a previous EOF
350 Returns: non-zero if the eof flag is set
362 /*************************************************
363 * SMTP version of ferror() *
364 *************************************************/
366 /* Tests for a previous read error, and returns with errno
367 restored to what it was when the error was detected.
370 Returns: non-zero if the error flag is set
376 errno = smtp_had_error;
377 return smtp_had_error;
382 /*************************************************
383 * Test for characters in the SMTP buffer *
384 *************************************************/
386 /* Used at the end of a message
395 return smtp_inptr < smtp_inend;
400 /*************************************************
401 * Write formatted string to SMTP channel *
402 *************************************************/
404 /* This is a separate function so that we don't have to repeat everything for
405 TLS support or debugging. It is global so that the daemon and the
406 authentication functions can use it. It does not return any error indication,
407 because major problems such as dropped connections won't show up till an output
408 flush for non-TLS connections. The smtp_fflush() function is available for
409 checking that: for convenience, TLS output errors are remembered here so that
410 they are also picked up later by smtp_fflush().
414 ... optional arguments
420 smtp_printf(const char *format, ...)
424 va_start(ap, format);
425 smtp_vprintf(format, ap);
429 /* This is split off so that verify.c:respond_printf() can, in effect, call
430 smtp_printf(), bearing in mind that in C a vararg function can't directly
431 call another vararg function, only a function which accepts a va_list. */
434 smtp_vprintf(const char *format, va_list ap)
438 yield = string_vformat(big_buffer, big_buffer_size, format, ap);
442 void *reset_point = store_get(0);
443 uschar *msg_copy, *cr, *end;
444 msg_copy = string_copy(big_buffer);
445 end = msg_copy + Ustrlen(msg_copy);
446 while ((cr = Ustrchr(msg_copy, '\r')) != NULL) /* lose CRs */
447 memmove(cr, cr + 1, (end--) - cr);
448 debug_printf("SMTP>> %s", msg_copy);
449 store_reset(reset_point);
454 log_write(0, LOG_MAIN|LOG_PANIC, "string too large in smtp_printf()");
455 smtp_closedown(US"Unexpected error");
456 exim_exit(EXIT_FAILURE);
459 /* If this is the first output for a (non-batch) RCPT command, see if all RCPTs
460 have had the same. Note: this code is also present in smtp_respond(). It would
461 be tidier to have it only in one place, but when it was added, it was easier to
462 do it that way, so as not to have to mess with the code for the RCPT command,
463 which sometimes uses smtp_printf() and sometimes smtp_respond(). */
465 if (rcpt_in_progress)
467 if (rcpt_smtp_response == NULL)
468 rcpt_smtp_response = string_copy(big_buffer);
469 else if (rcpt_smtp_response_same &&
470 Ustrcmp(rcpt_smtp_response, big_buffer) != 0)
471 rcpt_smtp_response_same = FALSE;
472 rcpt_in_progress = FALSE;
475 /* Now write the string */
478 if (tls_in.active >= 0)
480 if (tls_write(TRUE, big_buffer, Ustrlen(big_buffer)) < 0)
481 smtp_write_error = -1;
486 if (fprintf(smtp_out, "%s", big_buffer) < 0) smtp_write_error = -1;
491 /*************************************************
492 * Flush SMTP out and check for error *
493 *************************************************/
495 /* This function isn't currently used within Exim (it detects errors when it
496 tries to read the next SMTP input), but is available for use in local_scan().
497 For non-TLS connections, it flushes the output and checks for errors. For
498 TLS-connections, it checks for a previously-detected TLS write error.
501 Returns: 0 for no error; -1 after an error
507 if (tls_in.active < 0 && fflush(smtp_out) != 0) smtp_write_error = -1;
508 return smtp_write_error;
513 /*************************************************
514 * SMTP command read timeout *
515 *************************************************/
517 /* Signal handler for timing out incoming SMTP commands. This attempts to
520 Argument: signal number (SIGALRM)
525 command_timeout_handler(int sig)
527 sig = sig; /* Keep picky compilers happy */
528 log_write(L_lost_incoming_connection,
529 LOG_MAIN, "SMTP command timeout on%s connection from %s",
530 (tls_in.active >= 0)? " TLS" : "",
531 host_and_ident(FALSE));
532 if (smtp_batched_input)
533 moan_smtp_batch(NULL, "421 SMTP command timeout"); /* Does not return */
534 smtp_notquit_exit(US"command-timeout", US"421",
535 US"%s: SMTP command timeout - closing connection", smtp_active_hostname);
536 exim_exit(EXIT_FAILURE);
541 /*************************************************
543 *************************************************/
545 /* Signal handler for handling SIGTERM. Again, try to finish tidily.
547 Argument: signal number (SIGTERM)
552 command_sigterm_handler(int sig)
554 sig = sig; /* Keep picky compilers happy */
555 log_write(0, LOG_MAIN, "%s closed after SIGTERM", smtp_get_connection_info());
556 if (smtp_batched_input)
557 moan_smtp_batch(NULL, "421 SIGTERM received"); /* Does not return */
558 smtp_notquit_exit(US"signal-exit", US"421",
559 US"%s: Service not available - closing connection", smtp_active_hostname);
560 exim_exit(EXIT_FAILURE);
566 #ifdef EXPERIMENTAL_PROXY
567 /*************************************************
568 * Restore socket timeout to previous value *
569 *************************************************/
570 /* If the previous value was successfully retrieved, restore
571 it before returning control to the non-proxy routines
573 Arguments: fd - File descriptor for input
574 get_ok - Successfully retrieved previous values
575 tvtmp - Time struct with previous values
576 vslen - Length of time struct
580 restore_socket_timeout(int fd, int get_ok, struct timeval tvtmp, socklen_t vslen)
583 setsockopt(fd, SOL_SOCKET, SO_RCVTIMEO, (char *)&tvtmp, vslen);
586 /*************************************************
587 * Check if host is required proxy host *
588 *************************************************/
589 /* The function determines if inbound host will be a regular smtp host
590 or if it is configured that it must use Proxy Protocol.
597 check_proxy_protocol_host()
600 /* Cannot configure local connection as a proxy inbound */
601 if (sender_host_address == NULL) return proxy_session;
603 rc = verify_check_this_host(&proxy_required_hosts, NULL, NULL,
604 sender_host_address, NULL);
608 debug_printf("Detected proxy protocol configured host\n");
609 proxy_session = TRUE;
611 return proxy_session;
615 /*************************************************
616 * Setup host for proxy protocol *
617 *************************************************/
618 /* The function configures the connection based on a header from the
619 inbound host to use Proxy Protocol. The specification is very exact
620 so exit with an error if do not find the exact required pieces. This
621 includes an incorrect number of spaces separating args.
628 setup_proxy_protocol_host()
640 struct { /* TCP/UDP over IPv4, len = 12 */
646 struct { /* TCP/UDP over IPv6, len = 36 */
647 uint8_t src_addr[16];
648 uint8_t dst_addr[16];
652 struct { /* AF_UNIX sockets, len = 216 */
653 uschar src_addr[108];
654 uschar dst_addr[108];
660 /* Temp variables used in PPv2 address:port parsing */
662 char tmpip[INET_ADDRSTRLEN];
663 struct sockaddr_in tmpaddr;
664 char tmpip6[INET6_ADDRSTRLEN];
665 struct sockaddr_in6 tmpaddr6;
669 const char v2sig[12] = "\x0D\x0A\x0D\x0A\x00\x0D\x0A\x51\x55\x49\x54\x0A";
670 uschar *iptype; /* To display debug info */
673 struct timeval tvtmp;
675 vslen = sizeof(struct timeval);
677 fd = fileno(smtp_in);
679 /* Save current socket timeout values */
680 get_ok = getsockopt(fd, SOL_SOCKET, SO_RCVTIMEO, (char *)&tvtmp,
683 /* Proxy Protocol host must send header within a short time
684 (default 3 seconds) or it's considered invalid */
685 tv.tv_sec = PROXY_NEGOTIATION_TIMEOUT_SEC;
686 tv.tv_usec = PROXY_NEGOTIATION_TIMEOUT_USEC;
687 setsockopt(fd, SOL_SOCKET, SO_RCVTIMEO, (char *)&tv,
688 sizeof(struct timeval));
692 /* The inbound host was declared to be a Proxy Protocol host, so
693 don't do a PEEK into the data, actually slurp it up. */
694 ret = recv(fd, &hdr, sizeof(hdr), 0);
696 while (ret == -1 && errno == EINTR);
700 restore_socket_timeout(fd, get_ok, tvtmp, vslen);
701 return (errno == EAGAIN) ? 0 : ERRNO_PROXYFAIL;
705 memcmp(&hdr.v2, v2sig, 12) == 0)
709 /* May 2014: haproxy combined the version and command into one byte to
710 allow two full bytes for the length field in order to proxy SSL
711 connections. SSL Proxy is not supported in this version of Exim, but
712 must still seperate values here. */
713 ver = (hdr.v2.ver_cmd & 0xf0) >> 4;
714 cmd = (hdr.v2.ver_cmd & 0x0f);
718 DEBUG(D_receive) debug_printf("Invalid Proxy Protocol version: %d\n", ver);
721 DEBUG(D_receive) debug_printf("Detected PROXYv2 header\n");
722 /* The v2 header will always be 16 bytes per the spec. */
723 size = 16 + hdr.v2.len;
726 DEBUG(D_receive) debug_printf("Truncated or too large PROXYv2 header (%d/%d)\n",
732 case 0x01: /* PROXY command */
735 case 0x11: /* TCPv4 address type */
737 tmpaddr.sin_addr.s_addr = hdr.v2.addr.ip4.src_addr;
738 inet_ntop(AF_INET, &(tmpaddr.sin_addr), (char *)&tmpip, sizeof(tmpip));
739 if (!string_is_ip_address(US tmpip,NULL))
741 DEBUG(D_receive) debug_printf("Invalid %s source IP\n", iptype);
742 return ERRNO_PROXYFAIL;
744 proxy_host_address = sender_host_address;
745 sender_host_address = string_copy(US tmpip);
746 tmpport = ntohs(hdr.v2.addr.ip4.src_port);
747 proxy_host_port = sender_host_port;
748 sender_host_port = tmpport;
749 /* Save dest ip/port */
750 tmpaddr.sin_addr.s_addr = hdr.v2.addr.ip4.dst_addr;
751 inet_ntop(AF_INET, &(tmpaddr.sin_addr), (char *)&tmpip, sizeof(tmpip));
752 if (!string_is_ip_address(US tmpip,NULL))
754 DEBUG(D_receive) debug_printf("Invalid %s dest port\n", iptype);
755 return ERRNO_PROXYFAIL;
757 proxy_target_address = string_copy(US tmpip);
758 tmpport = ntohs(hdr.v2.addr.ip4.dst_port);
759 proxy_target_port = tmpport;
761 case 0x21: /* TCPv6 address type */
763 memmove(tmpaddr6.sin6_addr.s6_addr, hdr.v2.addr.ip6.src_addr, 16);
764 inet_ntop(AF_INET6, &(tmpaddr6.sin6_addr), (char *)&tmpip6, sizeof(tmpip6));
765 if (!string_is_ip_address(US tmpip6,NULL))
767 DEBUG(D_receive) debug_printf("Invalid %s source IP\n", iptype);
768 return ERRNO_PROXYFAIL;
770 proxy_host_address = sender_host_address;
771 sender_host_address = string_copy(US tmpip6);
772 tmpport = ntohs(hdr.v2.addr.ip6.src_port);
773 proxy_host_port = sender_host_port;
774 sender_host_port = tmpport;
775 /* Save dest ip/port */
776 memmove(tmpaddr6.sin6_addr.s6_addr, hdr.v2.addr.ip6.dst_addr, 16);
777 inet_ntop(AF_INET6, &(tmpaddr6.sin6_addr), (char *)&tmpip6, sizeof(tmpip6));
778 if (!string_is_ip_address(US tmpip6,NULL))
780 DEBUG(D_receive) debug_printf("Invalid %s dest port\n", iptype);
781 return ERRNO_PROXYFAIL;
783 proxy_target_address = string_copy(US tmpip6);
784 tmpport = ntohs(hdr.v2.addr.ip6.dst_port);
785 proxy_target_port = tmpport;
789 debug_printf("Unsupported PROXYv2 connection type: 0x%02x\n",
793 /* Unsupported protocol, keep local connection address */
795 case 0x00: /* LOCAL command */
796 /* Keep local connection address for LOCAL */
800 debug_printf("Unsupported PROXYv2 command: 0x%x\n", cmd);
805 memcmp(hdr.v1.line, "PROXY", 5) == 0)
807 uschar *p = string_copy(hdr.v1.line);
808 uschar *end = memchr(p, '\r', ret - 1);
809 uschar *sp; /* Utility variables follow */
813 if (!end || end[1] != '\n')
815 DEBUG(D_receive) debug_printf("Partial or invalid PROXY header\n");
818 *end = '\0'; /* Terminate the string */
819 size = end + 2 - hdr.v1.line; /* Skip header + CRLF */
820 DEBUG(D_receive) debug_printf("Detected PROXYv1 header\n");
821 /* Step through the string looking for the required fields. Ensure
822 strict adherance to required formatting, exit for any error. */
824 if (!isspace(*(p++)))
826 DEBUG(D_receive) debug_printf("Missing space after PROXY command\n");
829 if (!Ustrncmp(p, CCS"TCP4", 4))
831 else if (!Ustrncmp(p,CCS"TCP6", 4))
833 else if (!Ustrncmp(p,CCS"UNKNOWN", 7))
835 iptype = US"Unknown";
840 DEBUG(D_receive) debug_printf("Invalid TCP type\n");
844 p += Ustrlen(iptype);
845 if (!isspace(*(p++)))
847 DEBUG(D_receive) debug_printf("Missing space after TCP4/6 command\n");
850 /* Find the end of the arg */
851 if ((sp = Ustrchr(p, ' ')) == NULL)
854 debug_printf("Did not find proxied src %s\n", iptype);
858 if(!string_is_ip_address(p,NULL))
861 debug_printf("Proxied src arg is not an %s address\n", iptype);
864 proxy_host_address = sender_host_address;
865 sender_host_address = p;
867 if ((sp = Ustrchr(p, ' ')) == NULL)
870 debug_printf("Did not find proxy dest %s\n", iptype);
874 if(!string_is_ip_address(p,NULL))
877 debug_printf("Proxy dest arg is not an %s address\n", iptype);
880 proxy_target_address = p;
882 if ((sp = Ustrchr(p, ' ')) == NULL)
884 DEBUG(D_receive) debug_printf("Did not find proxied src port\n");
888 tmp_port = strtol(CCS p,&endc,10);
889 if (*endc || tmp_port == 0)
892 debug_printf("Proxied src port '%s' not an integer\n", p);
895 proxy_host_port = sender_host_port;
896 sender_host_port = tmp_port;
898 if ((sp = Ustrchr(p, '\0')) == NULL)
900 DEBUG(D_receive) debug_printf("Did not find proxy dest port\n");
903 tmp_port = strtol(CCS p,&endc,10);
904 if (*endc || tmp_port == 0)
907 debug_printf("Proxy dest port '%s' not an integer\n", p);
910 proxy_target_port = tmp_port;
911 /* Already checked for /r /n above. Good V1 header received. */
917 DEBUG(D_receive) debug_printf("Invalid proxy protocol version negotiation\n");
922 restore_socket_timeout(fd, get_ok, tvtmp, vslen);
923 /* Don't flush any potential buffer contents. Any input should cause a
924 synchronization failure */
928 restore_socket_timeout(fd, get_ok, tvtmp, vslen);
930 debug_printf("Valid %s sender from Proxy Protocol header\n", iptype);
931 return proxy_session;
935 /*************************************************
936 * Read one command line *
937 *************************************************/
939 /* Strictly, SMTP commands coming over the net are supposed to end with CRLF.
940 There are sites that don't do this, and in any case internal SMTP probably
941 should check only for LF. Consequently, we check here for LF only. The line
942 ends up with [CR]LF removed from its end. If we get an overlong line, treat as
943 an unknown command. The command is read into the global smtp_cmd_buffer so that
944 it is available via $smtp_command.
946 The character reading routine sets up a timeout for each block actually read
947 from the input (which may contain more than one command). We set up a special
948 signal handler that closes down the session on a timeout. Control does not
952 check_sync if TRUE, check synchronization rules if global option is TRUE
954 Returns: a code identifying the command (enumerated above)
958 smtp_read_command(BOOL check_sync)
963 BOOL hadnull = FALSE;
965 os_non_restarting_signal(SIGALRM, command_timeout_handler);
967 while ((c = (receive_getc)()) != '\n' && c != EOF)
969 if (ptr >= smtp_cmd_buffer_size)
971 os_non_restarting_signal(SIGALRM, sigalrm_handler);
979 smtp_cmd_buffer[ptr++] = c;
982 receive_linecount++; /* For BSMTP errors */
983 os_non_restarting_signal(SIGALRM, sigalrm_handler);
985 /* If hit end of file, return pseudo EOF command. Whether we have a
986 part-line already read doesn't matter, since this is an error state. */
988 if (c == EOF) return EOF_CMD;
990 /* Remove any CR and white space at the end of the line, and terminate the
993 while (ptr > 0 && isspace(smtp_cmd_buffer[ptr-1])) ptr--;
994 smtp_cmd_buffer[ptr] = 0;
996 DEBUG(D_receive) debug_printf("SMTP<< %s\n", smtp_cmd_buffer);
998 /* NULLs are not allowed in SMTP commands */
1000 if (hadnull) return BADCHAR_CMD;
1002 /* Scan command list and return identity, having set the data pointer
1003 to the start of the actual data characters. Check for SMTP synchronization
1006 for (p = cmd_list; p < cmd_list_end; p++)
1008 #ifdef EXPERIMENTAL_PROXY
1009 /* Only allow QUIT command if Proxy Protocol parsing failed */
1010 if (proxy_session && proxy_session_failed)
1012 if (p->cmd != QUIT_CMD)
1016 if (strncmpic(smtp_cmd_buffer, US p->name, p->len) == 0 &&
1017 (smtp_cmd_buffer[p->len-1] == ':' || /* "mail from:" or "rcpt to:" */
1018 smtp_cmd_buffer[p->len] == 0 ||
1019 smtp_cmd_buffer[p->len] == ' '))
1021 if (smtp_inptr < smtp_inend && /* Outstanding input */
1022 p->cmd < sync_cmd_limit && /* Command should sync */
1023 check_sync && /* Local flag set */
1024 smtp_enforce_sync && /* Global flag set */
1025 sender_host_address != NULL && /* Not local input */
1026 !sender_host_notsocket) /* Really is a socket */
1029 /* The variables $smtp_command and $smtp_command_argument point into the
1030 unmodified input buffer. A copy of the latter is taken for actual
1031 processing, so that it can be chopped up into separate parts if necessary,
1032 for example, when processing a MAIL command options such as SIZE that can
1033 follow the sender address. */
1035 smtp_cmd_argument = smtp_cmd_buffer + p->len;
1036 while (isspace(*smtp_cmd_argument)) smtp_cmd_argument++;
1037 Ustrcpy(smtp_data_buffer, smtp_cmd_argument);
1038 smtp_cmd_data = smtp_data_buffer;
1040 /* Count non-mail commands from those hosts that are controlled in this
1041 way. The default is all hosts. We don't waste effort checking the list
1042 until we get a non-mail command, but then cache the result to save checking
1043 again. If there's a DEFER while checking the host, assume it's in the list.
1045 Note that one instance of RSET, EHLO/HELO, and STARTTLS is allowed at the
1046 start of each incoming message by fiddling with the value in the table. */
1048 if (!p->is_mail_cmd)
1050 if (count_nonmail == TRUE_UNSET) count_nonmail =
1051 verify_check_host(&smtp_accept_max_nonmail_hosts) != FAIL;
1052 if (count_nonmail && ++nonmail_command_count > smtp_accept_max_nonmail)
1053 return TOO_MANY_NONMAIL_CMD;
1056 /* If there is data for a command that does not expect it, generate the
1059 return (p->has_arg || *smtp_cmd_data == 0)? p->cmd : BADARG_CMD;
1063 #ifdef EXPERIMENTAL_PROXY
1064 /* Only allow QUIT command if Proxy Protocol parsing failed */
1065 if (proxy_session && proxy_session_failed)
1066 return PROXY_FAIL_IGNORE_CMD;
1069 /* Enforce synchronization for unknown commands */
1071 if (smtp_inptr < smtp_inend && /* Outstanding input */
1072 check_sync && /* Local flag set */
1073 smtp_enforce_sync && /* Global flag set */
1074 sender_host_address != NULL && /* Not local input */
1075 !sender_host_notsocket) /* Really is a socket */
1083 /*************************************************
1084 * Recheck synchronization *
1085 *************************************************/
1087 /* Synchronization checks can never be perfect because a packet may be on its
1088 way but not arrived when the check is done. Such checks can in any case only be
1089 done when TLS is not in use. Normally, the checks happen when commands are
1090 read: Exim ensures that there is no more input in the input buffer. In normal
1091 cases, the response to the command will be fast, and there is no further check.
1093 However, for some commands an ACL is run, and that can include delays. In those
1094 cases, it is useful to do another check on the input just before sending the
1095 response. This also applies at the start of a connection. This function does
1096 that check by means of the select() function, as long as the facility is not
1097 disabled or inappropriate. A failure of select() is ignored.
1099 When there is unwanted input, we read it so that it appears in the log of the
1103 Returns: TRUE if all is well; FALSE if there is input pending
1111 struct timeval tzero;
1113 if (!smtp_enforce_sync || sender_host_address == NULL ||
1114 sender_host_notsocket || tls_in.active >= 0)
1117 fd = fileno(smtp_in);
1122 rc = select(fd + 1, (SELECT_ARG2_TYPE *)&fds, NULL, NULL, &tzero);
1124 if (rc <= 0) return TRUE; /* Not ready to read */
1126 if (rc < 0) return TRUE; /* End of file or error */
1129 rc = smtp_inend - smtp_inptr;
1130 if (rc > 150) rc = 150;
1137 /*************************************************
1138 * Forced closedown of call *
1139 *************************************************/
1141 /* This function is called from log.c when Exim is dying because of a serious
1142 disaster, and also from some other places. If an incoming non-batched SMTP
1143 channel is open, it swallows the rest of the incoming message if in the DATA
1144 phase, sends the reply string, and gives an error to all subsequent commands
1145 except QUIT. The existence of an SMTP call is detected by the non-NULLness of
1149 message SMTP reply string to send, excluding the code
1155 smtp_closedown(uschar *message)
1157 if (smtp_in == NULL || smtp_batched_input) return;
1158 receive_swallow_smtp();
1159 smtp_printf("421 %s\r\n", message);
1163 switch(smtp_read_command(FALSE))
1169 smtp_printf("221 %s closing connection\r\n", smtp_active_hostname);
1174 smtp_printf("250 Reset OK\r\n");
1178 smtp_printf("421 %s\r\n", message);
1187 /*************************************************
1188 * Set up connection info for logging *
1189 *************************************************/
1191 /* This function is called when logging information about an SMTP connection.
1192 It sets up appropriate source information, depending on the type of connection.
1193 If sender_fullhost is NULL, we are at a very early stage of the connection;
1194 just use the IP address.
1197 Returns: a string describing the connection
1201 smtp_get_connection_info(void)
1203 uschar *hostname = (sender_fullhost == NULL)?
1204 sender_host_address : sender_fullhost;
1207 return string_sprintf("SMTP connection from %s", hostname);
1209 if (sender_host_unknown || sender_host_notsocket)
1210 return string_sprintf("SMTP connection from %s", sender_ident);
1213 return string_sprintf("SMTP connection from %s (via inetd)", hostname);
1215 if ((log_extra_selector & LX_incoming_interface) != 0 &&
1216 interface_address != NULL)
1217 return string_sprintf("SMTP connection from %s I=[%s]:%d", hostname,
1218 interface_address, interface_port);
1220 return string_sprintf("SMTP connection from %s", hostname);
1226 /* Append TLS-related information to a log line
1229 s String under construction: allocated string to extend, or NULL
1230 sizep Pointer to current allocation size (update on return), or NULL
1231 ptrp Pointer to index for new entries in string (update on return), or NULL
1233 Returns: Allocated string or NULL
1236 s_tlslog(uschar * s, int * sizep, int * ptrp)
1238 int size = sizep ? *sizep : 0;
1239 int ptr = ptrp ? *ptrp : 0;
1241 if ((log_extra_selector & LX_tls_cipher) != 0 && tls_in.cipher != NULL)
1242 s = string_append(s, &size, &ptr, 2, US" X=", tls_in.cipher);
1243 if ((log_extra_selector & LX_tls_certificate_verified) != 0 &&
1244 tls_in.cipher != NULL)
1245 s = string_append(s, &size, &ptr, 2, US" CV=",
1246 tls_in.certificate_verified? "yes":"no");
1247 if ((log_extra_selector & LX_tls_peerdn) != 0 && tls_in.peerdn != NULL)
1248 s = string_append(s, &size, &ptr, 3, US" DN=\"",
1249 string_printing(tls_in.peerdn), US"\"");
1250 if ((log_extra_selector & LX_tls_sni) != 0 && tls_in.sni != NULL)
1251 s = string_append(s, &size, &ptr, 3, US" SNI=\"",
1252 string_printing(tls_in.sni), US"\"");
1257 if (sizep) *sizep = size;
1258 if (ptrp) *ptrp = ptr;
1264 /*************************************************
1265 * Log lack of MAIL if so configured *
1266 *************************************************/
1268 /* This function is called when an SMTP session ends. If the log selector
1269 smtp_no_mail is set, write a log line giving some details of what has happened
1270 in the SMTP session.
1277 smtp_log_no_mail(void)
1282 if (smtp_mailcmd_count > 0 || (log_extra_selector & LX_smtp_no_mail) == 0)
1288 if (sender_host_authenticated != NULL)
1290 s = string_append(s, &size, &ptr, 2, US" A=", sender_host_authenticated);
1291 if (authenticated_id != NULL)
1292 s = string_append(s, &size, &ptr, 2, US":", authenticated_id);
1296 s = s_tlslog(s, &size, &ptr);
1299 sep = (smtp_connection_had[SMTP_HBUFF_SIZE-1] != SCH_NONE)?
1300 US" C=..." : US" C=";
1301 for (i = smtp_ch_index; i < SMTP_HBUFF_SIZE; i++)
1303 if (smtp_connection_had[i] != SCH_NONE)
1305 s = string_append(s, &size, &ptr, 2, sep,
1306 smtp_names[smtp_connection_had[i]]);
1311 for (i = 0; i < smtp_ch_index; i++)
1313 s = string_append(s, &size, &ptr, 2, sep, smtp_names[smtp_connection_had[i]]);
1317 if (s != NULL) s[ptr] = 0; else s = US"";
1318 log_write(0, LOG_MAIN, "no MAIL in SMTP connection from %s D=%s%s",
1319 host_and_ident(FALSE),
1320 readconf_printtime(time(NULL) - smtp_connection_start), s);
1325 /*************************************************
1326 * Check HELO line and set sender_helo_name *
1327 *************************************************/
1329 /* Check the format of a HELO line. The data for HELO/EHLO is supposed to be
1330 the domain name of the sending host, or an ip literal in square brackets. The
1331 arrgument is placed in sender_helo_name, which is in malloc store, because it
1332 must persist over multiple incoming messages. If helo_accept_junk is set, this
1333 host is permitted to send any old junk (needed for some broken hosts).
1334 Otherwise, helo_allow_chars can be used for rogue characters in general
1335 (typically people want to let in underscores).
1338 s the data portion of the line (already past any white space)
1340 Returns: TRUE or FALSE
1344 check_helo(uschar *s)
1347 uschar *end = s + Ustrlen(s);
1348 BOOL yield = helo_accept_junk;
1350 /* Discard any previous helo name */
1352 if (sender_helo_name != NULL)
1354 store_free(sender_helo_name);
1355 sender_helo_name = NULL;
1358 /* Skip tests if junk is permitted. */
1362 /* Allow the new standard form for IPv6 address literals, namely,
1363 [IPv6:....], and because someone is bound to use it, allow an equivalent
1364 IPv4 form. Allow plain addresses as well. */
1371 if (strncmpic(s, US"[IPv6:", 6) == 0)
1372 yield = (string_is_ip_address(s+6, NULL) == 6);
1373 else if (strncmpic(s, US"[IPv4:", 6) == 0)
1374 yield = (string_is_ip_address(s+6, NULL) == 4);
1376 yield = (string_is_ip_address(s+1, NULL) != 0);
1381 /* Non-literals must be alpha, dot, hyphen, plus any non-valid chars
1382 that have been configured (usually underscore - sigh). */
1389 if (!isalnum(*s) && *s != '.' && *s != '-' &&
1390 Ustrchr(helo_allow_chars, *s) == NULL)
1400 /* Save argument if OK */
1402 if (yield) sender_helo_name = string_copy_malloc(start);
1410 /*************************************************
1411 * Extract SMTP command option *
1412 *************************************************/
1414 /* This function picks the next option setting off the end of smtp_cmd_data. It
1415 is called for MAIL FROM and RCPT TO commands, to pick off the optional ESMTP
1416 things that can appear there.
1419 name point this at the name
1420 value point this at the data string
1422 Returns: TRUE if found an option
1426 extract_option(uschar **name, uschar **value)
1429 uschar *v = smtp_cmd_data + Ustrlen(smtp_cmd_data) - 1;
1430 while (isspace(*v)) v--;
1432 while (v > smtp_cmd_data && *v != '=' && !isspace(*v)) v--;
1437 while(isalpha(n[-1])) n--;
1438 /* RFC says SP, but TAB seen in wild and other major MTAs accept it */
1439 if (!isspace(n[-1])) return FALSE;
1445 if (v == smtp_cmd_data) return FALSE;
1457 /*************************************************
1458 * Reset for new message *
1459 *************************************************/
1461 /* This function is called whenever the SMTP session is reset from
1462 within either of the setup functions.
1464 Argument: the stacking pool storage reset point
1469 smtp_reset(void *reset_point)
1471 store_reset(reset_point);
1472 recipients_list = NULL;
1473 rcpt_count = rcpt_defer_count = rcpt_fail_count =
1474 raw_recipients_count = recipients_count = recipients_list_max = 0;
1475 cancel_cutthrough_connection("smtp reset");
1476 message_linecount = 0;
1478 acl_added_headers = NULL;
1479 acl_removed_headers = NULL;
1480 queue_only_policy = FALSE;
1481 rcpt_smtp_response = NULL;
1482 rcpt_smtp_response_same = TRUE;
1483 rcpt_in_progress = FALSE;
1484 deliver_freeze = FALSE; /* Can be set by ACL */
1485 freeze_tell = freeze_tell_config; /* Can be set by ACL */
1486 fake_response = OK; /* Can be set by ACL */
1487 #ifdef WITH_CONTENT_SCAN
1488 no_mbox_unspool = FALSE; /* Can be set by ACL */
1490 submission_mode = FALSE; /* Can be set by ACL */
1491 suppress_local_fixups = suppress_local_fixups_default; /* Can be set by ACL */
1492 active_local_from_check = local_from_check; /* Can be set by ACL */
1493 active_local_sender_retain = local_sender_retain; /* Can be set by ACL */
1494 sender_address = NULL;
1495 submission_name = NULL; /* Can be set by ACL */
1496 raw_sender = NULL; /* After SMTP rewrite, before qualifying */
1497 sender_address_unrewritten = NULL; /* Set only after verify rewrite */
1498 sender_verified_list = NULL; /* No senders verified */
1499 memset(sender_address_cache, 0, sizeof(sender_address_cache));
1500 memset(sender_domain_cache, 0, sizeof(sender_domain_cache));
1502 #ifdef EXPERIMENTAL_DSN
1503 /* Reset the DSN flags */
1508 authenticated_sender = NULL;
1509 #ifdef EXPERIMENTAL_BRIGHTMAIL
1511 bmi_verdicts = NULL;
1513 #ifndef DISABLE_DKIM
1514 dkim_signers = NULL;
1515 dkim_disable_verify = FALSE;
1516 dkim_collect_input = FALSE;
1518 #ifdef EXPERIMENTAL_SPF
1519 spf_header_comment = NULL;
1520 spf_received = NULL;
1522 spf_smtp_comment = NULL;
1524 body_linecount = body_zerocount = 0;
1526 sender_rate = sender_rate_limit = sender_rate_period = NULL;
1527 ratelimiters_mail = NULL; /* Updated by ratelimit ACL condition */
1528 /* Note that ratelimiters_conn persists across resets. */
1530 /* Reset message ACL variables */
1534 /* The message body variables use malloc store. They may be set if this is
1535 not the first message in an SMTP session and the previous message caused them
1536 to be referenced in an ACL. */
1538 if (message_body != NULL)
1540 store_free(message_body);
1541 message_body = NULL;
1544 if (message_body_end != NULL)
1546 store_free(message_body_end);
1547 message_body_end = NULL;
1550 /* Warning log messages are also saved in malloc store. They are saved to avoid
1551 repetition in the same message, but it seems right to repeat them for different
1554 while (acl_warn_logged != NULL)
1556 string_item *this = acl_warn_logged;
1557 acl_warn_logged = acl_warn_logged->next;
1566 /*************************************************
1567 * Initialize for incoming batched SMTP message *
1568 *************************************************/
1570 /* This function is called from smtp_setup_msg() in the case when
1571 smtp_batched_input is true. This happens when -bS is used to pass a whole batch
1572 of messages in one file with SMTP commands between them. All errors must be
1573 reported by sending a message, and only MAIL FROM, RCPT TO, and DATA are
1574 relevant. After an error on a sender, or an invalid recipient, the remainder
1575 of the message is skipped. The value of received_protocol is already set.
1578 Returns: > 0 message successfully started (reached DATA)
1579 = 0 QUIT read or end of file reached
1580 < 0 should not occur
1584 smtp_setup_batch_msg(void)
1587 void *reset_point = store_get(0);
1589 /* Save the line count at the start of each transaction - single commands
1590 like HELO and RSET count as whole transactions. */
1592 bsmtp_transaction_linecount = receive_linecount;
1594 if ((receive_feof)()) return 0; /* Treat EOF as QUIT */
1596 smtp_reset(reset_point); /* Reset for start of message */
1598 /* Deal with SMTP commands. This loop is exited by setting done to a POSITIVE
1599 value. The values are 2 larger than the required yield of the function. */
1604 uschar *recipient = NULL;
1605 int start, end, sender_domain, recipient_domain;
1607 switch(smtp_read_command(FALSE))
1609 /* The HELO/EHLO commands set sender_address_helo if they have
1610 valid data; otherwise they are ignored, except that they do
1611 a reset of the state. */
1616 check_helo(smtp_cmd_data);
1620 smtp_reset(reset_point);
1621 bsmtp_transaction_linecount = receive_linecount;
1625 /* The MAIL FROM command requires an address as an operand. All we
1626 do here is to parse it for syntactic correctness. The form "<>" is
1627 a special case which converts into an empty string. The start/end
1628 pointers in the original are not used further for this address, as
1629 it is the canonical extracted address which is all that is kept. */
1632 if (sender_address != NULL)
1633 /* The function moan_smtp_batch() does not return. */
1634 moan_smtp_batch(smtp_cmd_buffer, "503 Sender already given");
1636 if (smtp_cmd_data[0] == 0)
1637 /* The function moan_smtp_batch() does not return. */
1638 moan_smtp_batch(smtp_cmd_buffer, "501 MAIL FROM must have an address operand");
1640 /* Reset to start of message */
1642 smtp_reset(reset_point);
1644 /* Apply SMTP rewrite */
1646 raw_sender = ((rewrite_existflags & rewrite_smtp) != 0)?
1647 rewrite_one(smtp_cmd_data, rewrite_smtp|rewrite_smtp_sender, NULL, FALSE,
1648 US"", global_rewrite_rules) : smtp_cmd_data;
1650 /* Extract the address; the TRUE flag allows <> as valid */
1653 parse_extract_address(raw_sender, &errmess, &start, &end, &sender_domain,
1656 if (raw_sender == NULL)
1657 /* The function moan_smtp_batch() does not return. */
1658 moan_smtp_batch(smtp_cmd_buffer, "501 %s", errmess);
1660 sender_address = string_copy(raw_sender);
1662 /* Qualify unqualified sender addresses if permitted to do so. */
1664 if (sender_domain == 0 && sender_address[0] != 0 && sender_address[0] != '@')
1666 if (allow_unqualified_sender)
1668 sender_address = rewrite_address_qualify(sender_address, FALSE);
1669 DEBUG(D_receive) debug_printf("unqualified address %s accepted "
1670 "and rewritten\n", raw_sender);
1672 /* The function moan_smtp_batch() does not return. */
1673 else moan_smtp_batch(smtp_cmd_buffer, "501 sender address must contain "
1679 /* The RCPT TO command requires an address as an operand. All we do
1680 here is to parse it for syntactic correctness. There may be any number
1681 of RCPT TO commands, specifying multiple senders. We build them all into
1682 a data structure that is in argc/argv format. The start/end values
1683 given by parse_extract_address are not used, as we keep only the
1684 extracted address. */
1687 if (sender_address == NULL)
1688 /* The function moan_smtp_batch() does not return. */
1689 moan_smtp_batch(smtp_cmd_buffer, "503 No sender yet given");
1691 if (smtp_cmd_data[0] == 0)
1692 /* The function moan_smtp_batch() does not return. */
1693 moan_smtp_batch(smtp_cmd_buffer, "501 RCPT TO must have an address operand");
1695 /* Check maximum number allowed */
1697 if (recipients_max > 0 && recipients_count + 1 > recipients_max)
1698 /* The function moan_smtp_batch() does not return. */
1699 moan_smtp_batch(smtp_cmd_buffer, "%s too many recipients",
1700 recipients_max_reject? "552": "452");
1702 /* Apply SMTP rewrite, then extract address. Don't allow "<>" as a
1703 recipient address */
1705 recipient = ((rewrite_existflags & rewrite_smtp) != 0)?
1706 rewrite_one(smtp_cmd_data, rewrite_smtp, NULL, FALSE, US"",
1707 global_rewrite_rules) : smtp_cmd_data;
1709 /* rfc821_domains = TRUE; << no longer needed */
1710 recipient = parse_extract_address(recipient, &errmess, &start, &end,
1711 &recipient_domain, FALSE);
1712 /* rfc821_domains = FALSE; << no longer needed */
1714 if (recipient == NULL)
1715 /* The function moan_smtp_batch() does not return. */
1716 moan_smtp_batch(smtp_cmd_buffer, "501 %s", errmess);
1718 /* If the recipient address is unqualified, qualify it if permitted. Then
1719 add it to the list of recipients. */
1721 if (recipient_domain == 0)
1723 if (allow_unqualified_recipient)
1725 DEBUG(D_receive) debug_printf("unqualified address %s accepted\n",
1727 recipient = rewrite_address_qualify(recipient, TRUE);
1729 /* The function moan_smtp_batch() does not return. */
1730 else moan_smtp_batch(smtp_cmd_buffer, "501 recipient address must contain "
1733 receive_add_recipient(recipient, -1);
1737 /* The DATA command is legal only if it follows successful MAIL FROM
1738 and RCPT TO commands. This function is complete when a valid DATA
1739 command is encountered. */
1742 if (sender_address == NULL || recipients_count <= 0)
1744 /* The function moan_smtp_batch() does not return. */
1745 if (sender_address == NULL)
1746 moan_smtp_batch(smtp_cmd_buffer,
1747 "503 MAIL FROM:<sender> command must precede DATA");
1749 moan_smtp_batch(smtp_cmd_buffer,
1750 "503 RCPT TO:<recipient> must precede DATA");
1754 done = 3; /* DATA successfully achieved */
1755 message_ended = END_NOTENDED; /* Indicate in middle of message */
1760 /* The VRFY, EXPN, HELP, ETRN, and NOOP commands are ignored. */
1767 bsmtp_transaction_linecount = receive_linecount;
1778 /* The function moan_smtp_batch() does not return. */
1779 moan_smtp_batch(smtp_cmd_buffer, "501 Unexpected argument data");
1784 /* The function moan_smtp_batch() does not return. */
1785 moan_smtp_batch(smtp_cmd_buffer, "501 Unexpected NULL in SMTP command");
1790 /* The function moan_smtp_batch() does not return. */
1791 moan_smtp_batch(smtp_cmd_buffer, "500 Command unrecognized");
1796 return done - 2; /* Convert yield values */
1802 /*************************************************
1803 * Start an SMTP session *
1804 *************************************************/
1806 /* This function is called at the start of an SMTP session. Thereafter,
1807 smtp_setup_msg() is called to initiate each separate message. This
1808 function does host-specific testing, and outputs the banner line.
1811 Returns: FALSE if the session can not continue; something has
1812 gone wrong, or the connection to the host is blocked
1816 smtp_start_session(void)
1820 uschar *user_msg, *log_msg;
1824 smtp_connection_start = time(NULL);
1825 for (smtp_ch_index = 0; smtp_ch_index < SMTP_HBUFF_SIZE; smtp_ch_index++)
1826 smtp_connection_had[smtp_ch_index] = SCH_NONE;
1829 /* Default values for certain variables */
1831 helo_seen = esmtp = helo_accept_junk = FALSE;
1832 smtp_mailcmd_count = 0;
1833 count_nonmail = TRUE_UNSET;
1834 synprot_error_count = unknown_command_count = nonmail_command_count = 0;
1835 smtp_delay_mail = smtp_rlm_base;
1836 auth_advertised = FALSE;
1837 pipelining_advertised = FALSE;
1838 pipelining_enable = TRUE;
1839 sync_cmd_limit = NON_SYNC_CMD_NON_PIPELINING;
1840 smtp_exit_function_called = FALSE; /* For avoiding loop in not-quit exit */
1842 memset(sender_host_cache, 0, sizeof(sender_host_cache));
1844 /* If receiving by -bs from a trusted user, or testing with -bh, we allow
1845 authentication settings from -oMaa to remain in force. */
1847 if (!host_checking && !sender_host_notsocket) sender_host_authenticated = NULL;
1848 authenticated_by = NULL;
1851 tls_in.cipher = tls_in.peerdn = NULL;
1852 tls_in.ourcert = tls_in.peercert = NULL;
1854 tls_in.ocsp = OCSP_NOT_REQ;
1855 tls_advertised = FALSE;
1857 #ifdef EXPERIMENTAL_DSN
1858 dsn_advertised = FALSE;
1861 /* Reset ACL connection variables */
1865 /* Allow for trailing 0 in the command and data buffers. */
1867 smtp_cmd_buffer = (uschar *)malloc(2*smtp_cmd_buffer_size + 2);
1868 if (smtp_cmd_buffer == NULL)
1869 log_write(0, LOG_MAIN|LOG_PANIC_DIE,
1870 "malloc() failed for SMTP command buffer");
1871 smtp_cmd_buffer[0] = 0;
1872 smtp_data_buffer = smtp_cmd_buffer + smtp_cmd_buffer_size + 1;
1874 /* For batched input, the protocol setting can be overridden from the
1875 command line by a trusted caller. */
1877 if (smtp_batched_input)
1879 if (received_protocol == NULL) received_protocol = US"local-bsmtp";
1882 /* For non-batched SMTP input, the protocol setting is forced here. It will be
1883 reset later if any of EHLO/AUTH/STARTTLS are received. */
1887 protocols[pnormal] + ((sender_host_address != NULL)? pnlocal : 0);
1889 /* Set up the buffer for inputting using direct read() calls, and arrange to
1890 call the local functions instead of the standard C ones. */
1892 smtp_inbuffer = (uschar *)malloc(in_buffer_size);
1893 if (smtp_inbuffer == NULL)
1894 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "malloc() failed for SMTP input buffer");
1895 receive_getc = smtp_getc;
1896 receive_ungetc = smtp_ungetc;
1897 receive_feof = smtp_feof;
1898 receive_ferror = smtp_ferror;
1899 receive_smtp_buffered = smtp_buffered;
1900 smtp_inptr = smtp_inend = smtp_inbuffer;
1901 smtp_had_eof = smtp_had_error = 0;
1903 /* Set up the message size limit; this may be host-specific */
1905 thismessage_size_limit = expand_string_integer(message_size_limit, TRUE);
1906 if (expand_string_message != NULL)
1908 if (thismessage_size_limit == -1)
1909 log_write(0, LOG_MAIN|LOG_PANIC, "unable to expand message_size_limit: "
1910 "%s", expand_string_message);
1912 log_write(0, LOG_MAIN|LOG_PANIC, "invalid message_size_limit: "
1913 "%s", expand_string_message);
1914 smtp_closedown(US"Temporary local problem - please try later");
1918 /* When a message is input locally via the -bs or -bS options, sender_host_
1919 unknown is set unless -oMa was used to force an IP address, in which case it
1920 is checked like a real remote connection. When -bs is used from inetd, this
1921 flag is not set, causing the sending host to be checked. The code that deals
1922 with IP source routing (if configured) is never required for -bs or -bS and
1923 the flag sender_host_notsocket is used to suppress it.
1925 If smtp_accept_max and smtp_accept_reserve are set, keep some connections in
1926 reserve for certain hosts and/or networks. */
1928 if (!sender_host_unknown)
1931 BOOL reserved_host = FALSE;
1933 /* Look up IP options (source routing info) on the socket if this is not an
1934 -oMa "host", and if any are found, log them and drop the connection.
1936 Linux (and others now, see below) is different to everyone else, so there
1937 has to be some conditional compilation here. Versions of Linux before 2.1.15
1938 used a structure whose name was "options". Somebody finally realized that
1939 this name was silly, and it got changed to "ip_options". I use the
1940 newer name here, but there is a fudge in the script that sets up os.h
1941 to define a macro in older Linux systems.
1943 Sigh. Linux is a fast-moving target. Another generation of Linux uses
1944 glibc 2, which has chosen ip_opts for the structure name. This is now
1945 really a glibc thing rather than a Linux thing, so the condition name
1946 has been changed to reflect this. It is relevant also to GNU/Hurd.
1948 Mac OS 10.x (Darwin) is like the later glibc versions, but without the
1949 setting of the __GLIBC__ macro, so we can't detect it automatically. There's
1950 a special macro defined in the os.h file.
1952 Some DGUX versions on older hardware appear not to support IP options at
1953 all, so there is now a general macro which can be set to cut out this
1956 How to do this properly in IPv6 is not yet known. */
1958 #if !HAVE_IPV6 && !defined(NO_IP_OPTIONS)
1960 #ifdef GLIBC_IP_OPTIONS
1961 #if (!defined __GLIBC__) || (__GLIBC__ < 2)
1966 #elif defined DARWIN_IP_OPTIONS
1972 if (!host_checking && !sender_host_notsocket)
1975 EXIM_SOCKLEN_T optlen = sizeof(struct ip_options) + MAX_IPOPTLEN;
1976 struct ip_options *ipopt = store_get(optlen);
1978 struct ip_opts ipoptblock;
1979 struct ip_opts *ipopt = &ipoptblock;
1980 EXIM_SOCKLEN_T optlen = sizeof(ipoptblock);
1982 struct ipoption ipoptblock;
1983 struct ipoption *ipopt = &ipoptblock;
1984 EXIM_SOCKLEN_T optlen = sizeof(ipoptblock);
1987 /* Occasional genuine failures of getsockopt() have been seen - for
1988 example, "reset by peer". Therefore, just log and give up on this
1989 call, unless the error is ENOPROTOOPT. This error is given by systems
1990 that have the interfaces but not the mechanism - e.g. GNU/Hurd at the time
1991 of writing. So for that error, carry on - we just can't do an IP options
1994 DEBUG(D_receive) debug_printf("checking for IP options\n");
1996 if (getsockopt(fileno(smtp_out), IPPROTO_IP, IP_OPTIONS, (uschar *)(ipopt),
1999 if (errno != ENOPROTOOPT)
2001 log_write(0, LOG_MAIN, "getsockopt() failed from %s: %s",
2002 host_and_ident(FALSE), strerror(errno));
2003 smtp_printf("451 SMTP service not available\r\n");
2008 /* Deal with any IP options that are set. On the systems I have looked at,
2009 the value of MAX_IPOPTLEN has been 40, meaning that there should never be
2010 more logging data than will fit in big_buffer. Nevertheless, after somebody
2011 questioned this code, I've added in some paranoid checking. */
2013 else if (optlen > 0)
2015 uschar *p = big_buffer;
2016 uschar *pend = big_buffer + big_buffer_size;
2017 uschar *opt, *adptr;
2019 struct in_addr addr;
2022 uschar *optstart = (uschar *)(ipopt->__data);
2024 uschar *optstart = (uschar *)(ipopt->ip_opts);
2026 uschar *optstart = (uschar *)(ipopt->ipopt_list);
2029 DEBUG(D_receive) debug_printf("IP options exist\n");
2031 Ustrcpy(p, "IP options on incoming call:");
2034 for (opt = optstart; opt != NULL &&
2035 opt < (uschar *)(ipopt) + optlen;)
2049 if (!string_format(p, pend-p, " %s [@%s",
2050 (*opt == IPOPT_SSRR)? "SSRR" : "LSRR",
2052 inet_ntoa(*((struct in_addr *)(&(ipopt->faddr))))))
2054 inet_ntoa(ipopt->ip_dst)))
2056 inet_ntoa(ipopt->ipopt_dst)))
2064 optcount = (opt[1] - 3) / sizeof(struct in_addr);
2066 while (optcount-- > 0)
2068 memcpy(&addr, adptr, sizeof(addr));
2069 if (!string_format(p, pend - p - 1, "%s%s",
2070 (optcount == 0)? ":" : "@", inet_ntoa(addr)))
2076 adptr += sizeof(struct in_addr);
2085 if (pend - p < 4 + 3*opt[1]) { opt = NULL; break; }
2088 for (i = 0; i < opt[1]; i++)
2090 sprintf(CS p, "%2.2x ", opt[i]);
2101 log_write(0, LOG_MAIN, "%s", big_buffer);
2103 /* Refuse any call with IP options. This is what tcpwrappers 7.5 does. */
2105 log_write(0, LOG_MAIN|LOG_REJECT,
2106 "connection from %s refused (IP options)", host_and_ident(FALSE));
2108 smtp_printf("554 SMTP service not available\r\n");
2112 /* Length of options = 0 => there are no options */
2114 else DEBUG(D_receive) debug_printf("no IP options found\n");
2116 #endif /* HAVE_IPV6 && !defined(NO_IP_OPTIONS) */
2118 /* Set keep-alive in socket options. The option is on by default. This
2119 setting is an attempt to get rid of some hanging connections that stick in
2120 read() when the remote end (usually a dialup) goes away. */
2122 if (smtp_accept_keepalive && !sender_host_notsocket)
2123 ip_keepalive(fileno(smtp_out), sender_host_address, FALSE);
2125 /* If the current host matches host_lookup, set the name by doing a
2126 reverse lookup. On failure, sender_host_name will be NULL and
2127 host_lookup_failed will be TRUE. This may or may not be serious - optional
2130 if (verify_check_host(&host_lookup) == OK)
2132 (void)host_name_lookup();
2133 host_build_sender_fullhost();
2136 /* Delay this until we have the full name, if it is looked up. */
2138 set_process_info("handling incoming connection from %s",
2139 host_and_ident(FALSE));
2141 /* Start up TLS if tls_on_connect is set. This is for supporting the legacy
2142 smtps port for use with older style SSL MTAs. */
2145 if (tls_in.on_connect && tls_server_start(tls_require_ciphers) != OK)
2149 /* Test for explicit connection rejection */
2151 if (verify_check_host(&host_reject_connection) == OK)
2153 log_write(L_connection_reject, LOG_MAIN|LOG_REJECT, "refused connection "
2154 "from %s (host_reject_connection)", host_and_ident(FALSE));
2155 smtp_printf("554 SMTP service not available\r\n");
2159 /* Test with TCP Wrappers if so configured. There is a problem in that
2160 hosts_ctl() returns 0 (deny) under a number of system failure circumstances,
2161 such as disks dying. In these cases, it is desirable to reject with a 4xx
2162 error instead of a 5xx error. There isn't a "right" way to detect such
2163 problems. The following kludge is used: errno is zeroed before calling
2164 hosts_ctl(). If the result is "reject", a 5xx error is given only if the
2165 value of errno is 0 or ENOENT (which happens if /etc/hosts.{allow,deny} does
2168 #ifdef USE_TCP_WRAPPERS
2170 tcp_wrappers_name = expand_string(tcp_wrappers_daemon_name);
2171 if (tcp_wrappers_name == NULL)
2173 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "Expansion of \"%s\" "
2174 "(tcp_wrappers_name) failed: %s", string_printing(tcp_wrappers_name),
2175 expand_string_message);
2177 if (!hosts_ctl(tcp_wrappers_name,
2178 (sender_host_name == NULL)? STRING_UNKNOWN : CS sender_host_name,
2179 (sender_host_address == NULL)? STRING_UNKNOWN : CS sender_host_address,
2180 (sender_ident == NULL)? STRING_UNKNOWN : CS sender_ident))
2182 if (errno == 0 || errno == ENOENT)
2184 HDEBUG(D_receive) debug_printf("tcp wrappers rejection\n");
2185 log_write(L_connection_reject,
2186 LOG_MAIN|LOG_REJECT, "refused connection from %s "
2187 "(tcp wrappers)", host_and_ident(FALSE));
2188 smtp_printf("554 SMTP service not available\r\n");
2192 int save_errno = errno;
2193 HDEBUG(D_receive) debug_printf("tcp wrappers rejected with unexpected "
2194 "errno value %d\n", save_errno);
2195 log_write(L_connection_reject,
2196 LOG_MAIN|LOG_REJECT, "temporarily refused connection from %s "
2197 "(tcp wrappers errno=%d)", host_and_ident(FALSE), save_errno);
2198 smtp_printf("451 Temporary local problem - please try later\r\n");
2204 /* Check for reserved slots. The value of smtp_accept_count has already been
2205 incremented to include this process. */
2207 if (smtp_accept_max > 0 &&
2208 smtp_accept_count > smtp_accept_max - smtp_accept_reserve)
2210 if ((rc = verify_check_host(&smtp_reserve_hosts)) != OK)
2212 log_write(L_connection_reject,
2213 LOG_MAIN, "temporarily refused connection from %s: not in "
2214 "reserve list: connected=%d max=%d reserve=%d%s",
2215 host_and_ident(FALSE), smtp_accept_count - 1, smtp_accept_max,
2216 smtp_accept_reserve, (rc == DEFER)? " (lookup deferred)" : "");
2217 smtp_printf("421 %s: Too many concurrent SMTP connections; "
2218 "please try again later\r\n", smtp_active_hostname);
2221 reserved_host = TRUE;
2224 /* If a load level above which only messages from reserved hosts are
2225 accepted is set, check the load. For incoming calls via the daemon, the
2226 check is done in the superior process if there are no reserved hosts, to
2227 save a fork. In all cases, the load average will already be available
2228 in a global variable at this point. */
2230 if (smtp_load_reserve >= 0 &&
2231 load_average > smtp_load_reserve &&
2233 verify_check_host(&smtp_reserve_hosts) != OK)
2235 log_write(L_connection_reject,
2236 LOG_MAIN, "temporarily refused connection from %s: not in "
2237 "reserve list and load average = %.2f", host_and_ident(FALSE),
2238 (double)load_average/1000.0);
2239 smtp_printf("421 %s: Too much load; please try again later\r\n",
2240 smtp_active_hostname);
2244 /* Determine whether unqualified senders or recipients are permitted
2245 for this host. Unfortunately, we have to do this every time, in order to
2246 set the flags so that they can be inspected when considering qualifying
2247 addresses in the headers. For a site that permits no qualification, this
2248 won't take long, however. */
2250 allow_unqualified_sender =
2251 verify_check_host(&sender_unqualified_hosts) == OK;
2253 allow_unqualified_recipient =
2254 verify_check_host(&recipient_unqualified_hosts) == OK;
2256 /* Determine whether HELO/EHLO is required for this host. The requirement
2257 can be hard or soft. */
2259 helo_required = verify_check_host(&helo_verify_hosts) == OK;
2261 helo_verify = verify_check_host(&helo_try_verify_hosts) == OK;
2263 /* Determine whether this hosts is permitted to send syntactic junk
2264 after a HELO or EHLO command. */
2266 helo_accept_junk = verify_check_host(&helo_accept_junk_hosts) == OK;
2269 /* For batch SMTP input we are now done. */
2271 if (smtp_batched_input) return TRUE;
2273 #ifdef EXPERIMENTAL_PROXY
2274 /* If valid Proxy Protocol source is connecting, set up session.
2275 * Failure will not allow any SMTP function other than QUIT. */
2276 proxy_session = FALSE;
2277 proxy_session_failed = FALSE;
2278 if (check_proxy_protocol_host())
2280 if (setup_proxy_protocol_host() == FALSE)
2282 proxy_session_failed = TRUE;
2284 debug_printf("Failure to extract proxied host, only QUIT allowed\n");
2288 sender_host_name = NULL;
2289 (void)host_name_lookup();
2290 host_build_sender_fullhost();
2295 /* Run the ACL if it exists */
2298 if (acl_smtp_connect != NULL)
2301 rc = acl_check(ACL_WHERE_CONNECT, NULL, acl_smtp_connect, &user_msg,
2305 (void)smtp_handle_acl_fail(ACL_WHERE_CONNECT, rc, user_msg, log_msg);
2310 /* Output the initial message for a two-way SMTP connection. It may contain
2311 newlines, which then cause a multi-line response to be given. */
2313 code = US"220"; /* Default status code */
2314 esc = US""; /* Default extended status code */
2315 esclen = 0; /* Length of esc */
2317 if (user_msg == NULL)
2319 s = expand_string(smtp_banner);
2321 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "Expansion of \"%s\" (smtp_banner) "
2322 "failed: %s", smtp_banner, expand_string_message);
2328 smtp_message_code(&code, &codelen, &s, NULL);
2332 esclen = codelen - 4;
2336 /* Remove any terminating newlines; might as well remove trailing space too */
2339 while (p > s && isspace(p[-1])) p--;
2342 /* It seems that CC:Mail is braindead, and assumes that the greeting message
2343 is all contained in a single IP packet. The original code wrote out the
2344 greeting using several calls to fprint/fputc, and on busy servers this could
2345 cause it to be split over more than one packet - which caused CC:Mail to fall
2346 over when it got the second part of the greeting after sending its first
2347 command. Sigh. To try to avoid this, build the complete greeting message
2348 first, and output it in one fell swoop. This gives a better chance of it
2349 ending up as a single packet. */
2351 ss = store_get(size);
2355 do /* At least once, in case we have an empty string */
2358 uschar *linebreak = Ustrchr(p, '\n');
2359 ss = string_cat(ss, &size, &ptr, code, 3);
2360 if (linebreak == NULL)
2363 ss = string_cat(ss, &size, &ptr, US" ", 1);
2367 len = linebreak - p;
2368 ss = string_cat(ss, &size, &ptr, US"-", 1);
2370 ss = string_cat(ss, &size, &ptr, esc, esclen);
2371 ss = string_cat(ss, &size, &ptr, p, len);
2372 ss = string_cat(ss, &size, &ptr, US"\r\n", 2);
2374 if (linebreak != NULL) p++;
2378 ss[ptr] = 0; /* string_cat leaves room for this */
2380 /* Before we write the banner, check that there is no input pending, unless
2381 this synchronisation check is disabled. */
2385 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP protocol "
2386 "synchronization error (input sent without waiting for greeting): "
2387 "rejected connection from %s input=\"%s\"", host_and_ident(TRUE),
2388 string_printing(smtp_inptr));
2389 smtp_printf("554 SMTP synchronization error\r\n");
2393 /* Now output the banner */
2395 smtp_printf("%s", ss);
2403 /*************************************************
2404 * Handle SMTP syntax and protocol errors *
2405 *************************************************/
2407 /* Write to the log for SMTP syntax errors in incoming commands, if configured
2408 to do so. Then transmit the error response. The return value depends on the
2409 number of syntax and protocol errors in this SMTP session.
2412 type error type, given as a log flag bit
2413 code response code; <= 0 means don't send a response
2414 data data to reflect in the response (can be NULL)
2415 errmess the error message
2417 Returns: -1 limit of syntax/protocol errors NOT exceeded
2418 +1 limit of syntax/protocol errors IS exceeded
2420 These values fit in with the values of the "done" variable in the main
2421 processing loop in smtp_setup_msg(). */
2424 synprot_error(int type, int code, uschar *data, uschar *errmess)
2428 log_write(type, LOG_MAIN, "SMTP %s error in \"%s\" %s %s",
2429 (type == L_smtp_syntax_error)? "syntax" : "protocol",
2430 string_printing(smtp_cmd_buffer), host_and_ident(TRUE), errmess);
2432 if (++synprot_error_count > smtp_max_synprot_errors)
2435 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
2436 "syntax or protocol errors (last command was \"%s\")",
2437 host_and_ident(FALSE), smtp_cmd_buffer);
2442 smtp_printf("%d%c%s%s%s\r\n", code, (yield == 1)? '-' : ' ',
2443 (data == NULL)? US"" : data, (data == NULL)? US"" : US": ", errmess);
2445 smtp_printf("%d Too many syntax or protocol errors\r\n", code);
2454 /*************************************************
2455 * Log incomplete transactions *
2456 *************************************************/
2458 /* This function is called after a transaction has been aborted by RSET, QUIT,
2459 connection drops or other errors. It logs the envelope information received
2460 so far in order to preserve address verification attempts.
2462 Argument: string to indicate what aborted the transaction
2467 incomplete_transaction_log(uschar *what)
2469 if (sender_address == NULL || /* No transaction in progress */
2470 (log_write_selector & L_smtp_incomplete_transaction) == 0 /* Not logging */
2473 /* Build list of recipients for logging */
2475 if (recipients_count > 0)
2478 raw_recipients = store_get(recipients_count * sizeof(uschar *));
2479 for (i = 0; i < recipients_count; i++)
2480 raw_recipients[i] = recipients_list[i].address;
2481 raw_recipients_count = recipients_count;
2484 log_write(L_smtp_incomplete_transaction, LOG_MAIN|LOG_SENDER|LOG_RECIPIENTS,
2485 "%s incomplete transaction (%s)", host_and_ident(TRUE), what);
2491 /*************************************************
2492 * Send SMTP response, possibly multiline *
2493 *************************************************/
2495 /* There are, it seems, broken clients out there that cannot handle multiline
2496 responses. If no_multiline_responses is TRUE (it can be set from an ACL), we
2497 output nothing for non-final calls, and only the first line for anything else.
2500 code SMTP code, may involve extended status codes
2501 codelen length of smtp code; if > 4 there's an ESC
2502 final FALSE if the last line isn't the final line
2503 msg message text, possibly containing newlines
2509 smtp_respond(uschar* code, int codelen, BOOL final, uschar *msg)
2514 if (!final && no_multiline_responses) return;
2519 esclen = codelen - 4;
2522 /* If this is the first output for a (non-batch) RCPT command, see if all RCPTs
2523 have had the same. Note: this code is also present in smtp_printf(). It would
2524 be tidier to have it only in one place, but when it was added, it was easier to
2525 do it that way, so as not to have to mess with the code for the RCPT command,
2526 which sometimes uses smtp_printf() and sometimes smtp_respond(). */
2528 if (rcpt_in_progress)
2530 if (rcpt_smtp_response == NULL)
2531 rcpt_smtp_response = string_copy(msg);
2532 else if (rcpt_smtp_response_same &&
2533 Ustrcmp(rcpt_smtp_response, msg) != 0)
2534 rcpt_smtp_response_same = FALSE;
2535 rcpt_in_progress = FALSE;
2538 /* Not output the message, splitting it up into multiple lines if necessary. */
2542 uschar *nl = Ustrchr(msg, '\n');
2545 smtp_printf("%.3s%c%.*s%s\r\n", code, final? ' ':'-', esclen, esc, msg);
2548 else if (nl[1] == 0 || no_multiline_responses)
2550 smtp_printf("%.3s%c%.*s%.*s\r\n", code, final? ' ':'-', esclen, esc,
2551 (int)(nl - msg), msg);
2556 smtp_printf("%.3s-%.*s%.*s\r\n", code, esclen, esc, (int)(nl - msg), msg);
2558 while (isspace(*msg)) msg++;
2566 /*************************************************
2567 * Parse user SMTP message *
2568 *************************************************/
2570 /* This function allows for user messages overriding the response code details
2571 by providing a suitable response code string at the start of the message
2572 user_msg. Check the message for starting with a response code and optionally an
2573 extended status code. If found, check that the first digit is valid, and if so,
2574 change the code pointer and length to use the replacement. An invalid code
2575 causes a panic log; in this case, if the log messages is the same as the user
2576 message, we must also adjust the value of the log message to show the code that
2577 is actually going to be used (the original one).
2579 This function is global because it is called from receive.c as well as within
2582 Note that the code length returned includes the terminating whitespace
2583 character, which is always included in the regex match.
2586 code SMTP code, may involve extended status codes
2587 codelen length of smtp code; if > 4 there's an ESC
2589 log_msg optional log message, to be adjusted with the new SMTP code
2595 smtp_message_code(uschar **code, int *codelen, uschar **msg, uschar **log_msg)
2600 if (msg == NULL || *msg == NULL) return;
2602 n = pcre_exec(regex_smtp_code, NULL, CS *msg, Ustrlen(*msg), 0,
2603 PCRE_EOPT, ovector, sizeof(ovector)/sizeof(int));
2606 if ((*msg)[0] != (*code)[0])
2608 log_write(0, LOG_MAIN|LOG_PANIC, "configured error code starts with "
2609 "incorrect digit (expected %c) in \"%s\"", (*code)[0], *msg);
2610 if (log_msg != NULL && *log_msg == *msg)
2611 *log_msg = string_sprintf("%s %s", *code, *log_msg + ovector[1]);
2616 *codelen = ovector[1]; /* Includes final space */
2618 *msg += ovector[1]; /* Chop the code off the message */
2625 /*************************************************
2626 * Handle an ACL failure *
2627 *************************************************/
2629 /* This function is called when acl_check() fails. As well as calls from within
2630 this module, it is called from receive.c for an ACL after DATA. It sorts out
2631 logging the incident, and sets up the error response. A message containing
2632 newlines is turned into a multiline SMTP response, but for logging, only the
2635 There's a table of default permanent failure response codes to use in
2636 globals.c, along with the table of names. VFRY is special. Despite RFC1123 it
2637 defaults disabled in Exim. However, discussion in connection with RFC 821bis
2638 (aka RFC 2821) has concluded that the response should be 252 in the disabled
2639 state, because there are broken clients that try VRFY before RCPT. A 5xx
2640 response should be given only when the address is positively known to be
2641 undeliverable. Sigh. Also, for ETRN, 458 is given on refusal, and for AUTH,
2644 From Exim 4.63, it is possible to override the response code details by
2645 providing a suitable response code string at the start of the message provided
2646 in user_msg. The code's first digit is checked for validity.
2649 where where the ACL was called from
2651 user_msg a message that can be included in an SMTP response
2652 log_msg a message for logging
2654 Returns: 0 in most cases
2655 2 if the failure code was FAIL_DROP, in which case the
2656 SMTP connection should be dropped (this value fits with the
2657 "done" variable in smtp_setup_msg() below)
2661 smtp_handle_acl_fail(int where, int rc, uschar *user_msg, uschar *log_msg)
2663 BOOL drop = rc == FAIL_DROP;
2667 uschar *sender_info = US"";
2669 #ifdef WITH_CONTENT_SCAN
2670 (where == ACL_WHERE_MIME)? US"during MIME ACL checks" :
2672 (where == ACL_WHERE_PREDATA)? US"DATA" :
2673 (where == ACL_WHERE_DATA)? US"after DATA" :
2674 #ifndef DISABLE_PRDR
2675 (where == ACL_WHERE_PRDR)? US"after DATA PRDR" :
2677 (smtp_cmd_data == NULL)?
2678 string_sprintf("%s in \"connect\" ACL", acl_wherenames[where]) :
2679 string_sprintf("%s %s", acl_wherenames[where], smtp_cmd_data);
2681 if (drop) rc = FAIL;
2683 /* Set the default SMTP code, and allow a user message to change it. */
2685 smtp_code = (rc != FAIL)? US"451" : acl_wherecodes[where];
2686 smtp_message_code(&smtp_code, &codelen, &user_msg, &log_msg);
2688 /* We used to have sender_address here; however, there was a bug that was not
2689 updating sender_address after a rewrite during a verify. When this bug was
2690 fixed, sender_address at this point became the rewritten address. I'm not sure
2691 this is what should be logged, so I've changed to logging the unrewritten
2692 address to retain backward compatibility. */
2694 #ifndef WITH_CONTENT_SCAN
2695 if (where == ACL_WHERE_RCPT || where == ACL_WHERE_DATA)
2697 if (where == ACL_WHERE_RCPT || where == ACL_WHERE_DATA || where == ACL_WHERE_MIME)
2700 sender_info = string_sprintf("F=<%s>%s%s%s%s ",
2701 sender_address_unrewritten ? sender_address_unrewritten : sender_address,
2702 sender_host_authenticated ? US" A=" : US"",
2703 sender_host_authenticated ? sender_host_authenticated : US"",
2704 sender_host_authenticated && authenticated_id ? US":" : US"",
2705 sender_host_authenticated && authenticated_id ? authenticated_id : US""
2709 /* If there's been a sender verification failure with a specific message, and
2710 we have not sent a response about it yet, do so now, as a preliminary line for
2711 failures, but not defers. However, always log it for defer, and log it for fail
2712 unless the sender_verify_fail log selector has been turned off. */
2714 if (sender_verified_failed != NULL &&
2715 !testflag(sender_verified_failed, af_sverify_told))
2717 BOOL save_rcpt_in_progress = rcpt_in_progress;
2718 rcpt_in_progress = FALSE; /* So as not to treat these as the error */
2720 setflag(sender_verified_failed, af_sverify_told);
2722 if (rc != FAIL || (log_extra_selector & LX_sender_verify_fail) != 0)
2723 log_write(0, LOG_MAIN|LOG_REJECT, "%s sender verify %s for <%s>%s",
2724 host_and_ident(TRUE),
2725 ((sender_verified_failed->special_action & 255) == DEFER)? "defer":"fail",
2726 sender_verified_failed->address,
2727 (sender_verified_failed->message == NULL)? US"" :
2728 string_sprintf(": %s", sender_verified_failed->message));
2730 if (rc == FAIL && sender_verified_failed->user_message != NULL)
2731 smtp_respond(smtp_code, codelen, FALSE, string_sprintf(
2732 testflag(sender_verified_failed, af_verify_pmfail)?
2733 "Postmaster verification failed while checking <%s>\n%s\n"
2734 "Several RFCs state that you are required to have a postmaster\n"
2735 "mailbox for each mail domain. This host does not accept mail\n"
2736 "from domains whose servers reject the postmaster address."
2738 testflag(sender_verified_failed, af_verify_nsfail)?
2739 "Callback setup failed while verifying <%s>\n%s\n"
2740 "The initial connection, or a HELO or MAIL FROM:<> command was\n"
2741 "rejected. Refusing MAIL FROM:<> does not help fight spam, disregards\n"
2742 "RFC requirements, and stops you from receiving standard bounce\n"
2743 "messages. This host does not accept mail from domains whose servers\n"
2746 "Verification failed for <%s>\n%s",
2747 sender_verified_failed->address,
2748 sender_verified_failed->user_message));
2750 rcpt_in_progress = save_rcpt_in_progress;
2753 /* Sort out text for logging */
2755 log_msg = (log_msg == NULL)? US"" : string_sprintf(": %s", log_msg);
2756 lognl = Ustrchr(log_msg, '\n');
2757 if (lognl != NULL) *lognl = 0;
2759 /* Send permanent failure response to the command, but the code used isn't
2760 always a 5xx one - see comments at the start of this function. If the original
2761 rc was FAIL_DROP we drop the connection and yield 2. */
2763 if (rc == FAIL) smtp_respond(smtp_code, codelen, TRUE, (user_msg == NULL)?
2764 US"Administrative prohibition" : user_msg);
2766 /* Send temporary failure response to the command. Don't give any details,
2767 unless acl_temp_details is set. This is TRUE for a callout defer, a "defer"
2768 verb, and for a header verify when smtp_return_error_details is set.
2770 This conditional logic is all somewhat of a mess because of the odd
2771 interactions between temp_details and return_error_details. One day it should
2772 be re-implemented in a tidier fashion. */
2776 if (acl_temp_details && user_msg != NULL)
2778 if (smtp_return_error_details &&
2779 sender_verified_failed != NULL &&
2780 sender_verified_failed->message != NULL)
2782 smtp_respond(smtp_code, codelen, FALSE, sender_verified_failed->message);
2784 smtp_respond(smtp_code, codelen, TRUE, user_msg);
2787 smtp_respond(smtp_code, codelen, TRUE,
2788 US"Temporary local problem - please try later");
2791 /* Log the incident to the logs that are specified by log_reject_target
2792 (default main, reject). This can be empty to suppress logging of rejections. If
2793 the connection is not forcibly to be dropped, return 0. Otherwise, log why it
2794 is closing if required and return 2. */
2796 if (log_reject_target != 0)
2799 uschar * s = s_tlslog(NULL, NULL, NULL);
2804 log_write(0, log_reject_target, "%s%s %s%srejected %s%s",
2805 host_and_ident(TRUE), s,
2806 sender_info, (rc == FAIL)? US"" : US"temporarily ", what, log_msg);
2809 if (!drop) return 0;
2811 log_write(L_smtp_connection, LOG_MAIN, "%s closed by DROP in ACL",
2812 smtp_get_connection_info());
2814 /* Run the not-quit ACL, but without any custom messages. This should not be a
2815 problem, because we get here only if some other ACL has issued "drop", and
2816 in that case, *its* custom messages will have been used above. */
2818 smtp_notquit_exit(US"acl-drop", NULL, NULL);
2825 /*************************************************
2826 * Handle SMTP exit when QUIT is not given *
2827 *************************************************/
2829 /* This function provides a logging/statistics hook for when an SMTP connection
2830 is dropped on the floor or the other end goes away. It's a global function
2831 because it's called from receive.c as well as this module. As well as running
2832 the NOTQUIT ACL, if there is one, this function also outputs a final SMTP
2833 response, either with a custom message from the ACL, or using a default. There
2834 is one case, however, when no message is output - after "drop". In that case,
2835 the ACL that obeyed "drop" has already supplied the custom message, and NULL is
2836 passed to this function.
2838 In case things go wrong while processing this function, causing an error that
2839 may re-enter this funtion, there is a recursion check.
2842 reason What $smtp_notquit_reason will be set to in the ACL;
2843 if NULL, the ACL is not run
2844 code The error code to return as part of the response
2845 defaultrespond The default message if there's no user_msg
2851 smtp_notquit_exit(uschar *reason, uschar *code, uschar *defaultrespond, ...)
2854 uschar *user_msg = NULL;
2855 uschar *log_msg = NULL;
2857 /* Check for recursive acll */
2859 if (smtp_exit_function_called)
2861 log_write(0, LOG_PANIC, "smtp_notquit_exit() called more than once (%s)",
2865 smtp_exit_function_called = TRUE;
2867 /* Call the not-QUIT ACL, if there is one, unless no reason is given. */
2869 if (acl_smtp_notquit != NULL && reason != NULL)
2871 smtp_notquit_reason = reason;
2872 rc = acl_check(ACL_WHERE_NOTQUIT, NULL, acl_smtp_notquit, &user_msg,
2875 log_write(0, LOG_MAIN|LOG_PANIC, "ACL for not-QUIT returned ERROR: %s",
2879 /* Write an SMTP response if we are expected to give one. As the default
2880 responses are all internal, they should always fit in the buffer, but code a
2881 warning, just in case. Note that string_vformat() still leaves a complete
2882 string, even if it is incomplete. */
2884 if (code != NULL && defaultrespond != NULL)
2886 if (user_msg == NULL)
2890 va_start(ap, defaultrespond);
2891 if (!string_vformat(buffer, sizeof(buffer), CS defaultrespond, ap))
2892 log_write(0, LOG_MAIN|LOG_PANIC, "string too large in smtp_notquit_exit()");
2893 smtp_printf("%s %s\r\n", code, buffer);
2897 smtp_respond(code, 3, TRUE, user_msg);
2905 /*************************************************
2906 * Verify HELO argument *
2907 *************************************************/
2909 /* This function is called if helo_verify_hosts or helo_try_verify_hosts is
2910 matched. It is also called from ACL processing if verify = helo is used and
2911 verification was not previously tried (i.e. helo_try_verify_hosts was not
2912 matched). The result of its processing is to set helo_verified and
2913 helo_verify_failed. These variables should both be FALSE for this function to
2916 Note that EHLO/HELO is legitimately allowed to quote an address literal. Allow
2917 for IPv6 ::ffff: literals.
2920 Returns: TRUE if testing was completed;
2921 FALSE on a temporary failure
2925 smtp_verify_helo(void)
2929 HDEBUG(D_receive) debug_printf("verifying EHLO/HELO argument \"%s\"\n",
2932 if (sender_helo_name == NULL)
2934 HDEBUG(D_receive) debug_printf("no EHLO/HELO command was issued\n");
2937 /* Deal with the case of -bs without an IP address */
2939 else if (sender_host_address == NULL)
2941 HDEBUG(D_receive) debug_printf("no client IP address: assume success\n");
2942 helo_verified = TRUE;
2945 /* Deal with the more common case when there is a sending IP address */
2947 else if (sender_helo_name[0] == '[')
2949 helo_verified = Ustrncmp(sender_helo_name+1, sender_host_address,
2950 Ustrlen(sender_host_address)) == 0;
2955 if (strncmpic(sender_host_address, US"::ffff:", 7) == 0)
2956 helo_verified = Ustrncmp(sender_helo_name + 1,
2957 sender_host_address + 7, Ustrlen(sender_host_address) - 7) == 0;
2962 { if (helo_verified) debug_printf("matched host address\n"); }
2965 /* Do a reverse lookup if one hasn't already given a positive or negative
2966 response. If that fails, or the name doesn't match, try checking with a forward
2971 if (sender_host_name == NULL && !host_lookup_failed)
2972 yield = host_name_lookup() != DEFER;
2974 /* If a host name is known, check it and all its aliases. */
2976 if (sender_host_name != NULL)
2978 helo_verified = strcmpic(sender_host_name, sender_helo_name) == 0;
2982 HDEBUG(D_receive) debug_printf("matched host name\n");
2986 uschar **aliases = sender_host_aliases;
2987 while (*aliases != NULL)
2989 helo_verified = strcmpic(*aliases++, sender_helo_name) == 0;
2990 if (helo_verified) break;
2995 debug_printf("matched alias %s\n", *(--aliases));
3000 /* Final attempt: try a forward lookup of the helo name */
3006 h.name = sender_helo_name;
3010 HDEBUG(D_receive) debug_printf("getting IP address for %s\n",
3012 rc = host_find_byname(&h, NULL, 0, NULL, TRUE);
3013 if (rc == HOST_FOUND || rc == HOST_FOUND_LOCAL)
3018 if (Ustrcmp(hh->address, sender_host_address) == 0)
3020 helo_verified = TRUE;
3022 debug_printf("IP address for %s matches calling address\n",
3032 if (!helo_verified) helo_verify_failed = TRUE; /* We've tried ... */
3039 /*************************************************
3040 * Send user response message *
3041 *************************************************/
3043 /* This function is passed a default response code and a user message. It calls
3044 smtp_message_code() to check and possibly modify the response code, and then
3045 calls smtp_respond() to transmit the response. I put this into a function
3046 just to avoid a lot of repetition.
3049 code the response code
3050 user_msg the user message
3056 smtp_user_msg(uschar *code, uschar *user_msg)
3059 smtp_message_code(&code, &len, &user_msg, NULL);
3060 smtp_respond(code, len, TRUE, user_msg);
3065 /*************************************************
3066 * Initialize for SMTP incoming message *
3067 *************************************************/
3069 /* This function conducts the initial dialogue at the start of an incoming SMTP
3070 message, and builds a list of recipients. However, if the incoming message
3071 is part of a batch (-bS option) a separate function is called since it would
3072 be messy having tests splattered about all over this function. This function
3073 therefore handles the case where interaction is occurring. The input and output
3074 files are set up in smtp_in and smtp_out.
3076 The global recipients_list is set to point to a vector of recipient_item
3077 blocks, whose number is given by recipients_count. This is extended by the
3078 receive_add_recipient() function. The global variable sender_address is set to
3079 the sender's address. The yield is +1 if a message has been successfully
3080 started, 0 if a QUIT command was encountered or the connection was refused from
3081 the particular host, or -1 if the connection was lost.
3085 Returns: > 0 message successfully started (reached DATA)
3086 = 0 QUIT read or end of file reached or call refused
3091 smtp_setup_msg(void)
3094 BOOL toomany = FALSE;
3095 BOOL discarded = FALSE;
3096 BOOL last_was_rej_mail = FALSE;
3097 BOOL last_was_rcpt = FALSE;
3098 void *reset_point = store_get(0);
3100 DEBUG(D_receive) debug_printf("smtp_setup_msg entered\n");
3102 /* Reset for start of new message. We allow one RSET not to be counted as a
3103 nonmail command, for those MTAs that insist on sending it between every
3104 message. Ditto for EHLO/HELO and for STARTTLS, to allow for going in and out of
3105 TLS between messages (an Exim client may do this if it has messages queued up
3106 for the host). Note: we do NOT reset AUTH at this point. */
3108 smtp_reset(reset_point);
3109 message_ended = END_NOTSTARTED;
3111 cmd_list[CMD_LIST_RSET].is_mail_cmd = TRUE;
3112 cmd_list[CMD_LIST_HELO].is_mail_cmd = TRUE;
3113 cmd_list[CMD_LIST_EHLO].is_mail_cmd = TRUE;
3115 cmd_list[CMD_LIST_STARTTLS].is_mail_cmd = TRUE;
3118 /* Set the local signal handler for SIGTERM - it tries to end off tidily */
3120 os_non_restarting_signal(SIGTERM, command_sigterm_handler);
3122 /* Batched SMTP is handled in a different function. */
3124 if (smtp_batched_input) return smtp_setup_batch_msg();
3126 /* Deal with SMTP commands. This loop is exited by setting done to a POSITIVE
3127 value. The values are 2 larger than the required yield of the function. */
3132 uschar *etrn_command;
3133 uschar *etrn_serialize_key;
3135 uschar *log_msg, *smtp_code;
3136 uschar *user_msg = NULL;
3137 uschar *recipient = NULL;
3138 uschar *hello = NULL;
3139 uschar *set_id = NULL;
3141 BOOL was_rej_mail = FALSE;
3142 BOOL was_rcpt = FALSE;
3143 void (*oldsignal)(int);
3145 int start, end, sender_domain, recipient_domain;
3149 #ifdef EXPERIMENTAL_DSN
3150 uschar *orcpt = NULL;
3154 switch(smtp_read_command(TRUE))
3156 /* The AUTH command is not permitted to occur inside a transaction, and may
3157 occur successfully only once per connection. Actually, that isn't quite
3158 true. When TLS is started, all previous information about a connection must
3159 be discarded, so a new AUTH is permitted at that time.
3161 AUTH may only be used when it has been advertised. However, it seems that
3162 there are clients that send AUTH when it hasn't been advertised, some of
3163 them even doing this after HELO. And there are MTAs that accept this. Sigh.
3164 So there's a get-out that allows this to happen.
3166 AUTH is initially labelled as a "nonmail command" so that one occurrence
3167 doesn't get counted. We change the label here so that multiple failing
3168 AUTHS will eventually hit the nonmail threshold. */
3172 authentication_failed = TRUE;
3173 cmd_list[CMD_LIST_AUTH].is_mail_cmd = FALSE;
3175 if (!auth_advertised && !allow_auth_unadvertised)
3177 done = synprot_error(L_smtp_protocol_error, 503, NULL,
3178 US"AUTH command used when not advertised");
3181 if (sender_host_authenticated != NULL)
3183 done = synprot_error(L_smtp_protocol_error, 503, NULL,
3184 US"already authenticated");
3187 if (sender_address != NULL)
3189 done = synprot_error(L_smtp_protocol_error, 503, NULL,
3190 US"not permitted in mail transaction");
3196 if (acl_smtp_auth != NULL)
3198 rc = acl_check(ACL_WHERE_AUTH, NULL, acl_smtp_auth, &user_msg, &log_msg);
3201 done = smtp_handle_acl_fail(ACL_WHERE_AUTH, rc, user_msg, log_msg);
3206 /* Find the name of the requested authentication mechanism. */
3209 while ((c = *smtp_cmd_data) != 0 && !isspace(c))
3211 if (!isalnum(c) && c != '-' && c != '_')
3213 done = synprot_error(L_smtp_syntax_error, 501, NULL,
3214 US"invalid character in authentication mechanism name");
3220 /* If not at the end of the line, we must be at white space. Terminate the
3221 name and move the pointer on to any data that may be present. */
3223 if (*smtp_cmd_data != 0)
3225 *smtp_cmd_data++ = 0;
3226 while (isspace(*smtp_cmd_data)) smtp_cmd_data++;
3229 /* Search for an authentication mechanism which is configured for use
3230 as a server and which has been advertised (unless, sigh, allow_auth_
3231 unadvertised is set). */
3233 for (au = auths; au != NULL; au = au->next)
3235 if (strcmpic(s, au->public_name) == 0 && au->server &&
3236 (au->advertised || allow_auth_unadvertised)) break;
3241 done = synprot_error(L_smtp_protocol_error, 504, NULL,
3242 string_sprintf("%s authentication mechanism not supported", s));
3246 /* Run the checking code, passing the remainder of the command line as
3247 data. Initials the $auth<n> variables as empty. Initialize $0 empty and set
3248 it as the only set numerical variable. The authenticator may set $auth<n>
3249 and also set other numeric variables. The $auth<n> variables are preferred
3250 nowadays; the numerical variables remain for backwards compatibility.
3252 Afterwards, have a go at expanding the set_id string, even if
3253 authentication failed - for bad passwords it can be useful to log the
3254 userid. On success, require set_id to expand and exist, and put it in
3255 authenticated_id. Save this in permanent store, as the working store gets
3256 reset at HELO, RSET, etc. */
3258 for (i = 0; i < AUTH_VARS; i++) auth_vars[i] = NULL;
3260 expand_nlength[0] = 0; /* $0 contains nothing */
3262 c = (au->info->servercode)(au, smtp_cmd_data);
3263 if (au->set_id != NULL) set_id = expand_string(au->set_id);
3264 expand_nmax = -1; /* Reset numeric variables */
3265 for (i = 0; i < AUTH_VARS; i++) auth_vars[i] = NULL; /* Reset $auth<n> */
3267 /* The value of authenticated_id is stored in the spool file and printed in
3268 log lines. It must not contain binary zeros or newline characters. In
3269 normal use, it never will, but when playing around or testing, this error
3270 can (did) happen. To guard against this, ensure that the id contains only
3271 printing characters. */
3273 if (set_id != NULL) set_id = string_printing(set_id);
3275 /* For the non-OK cases, set up additional logging data if set_id
3280 if (set_id != NULL && *set_id != 0)
3281 set_id = string_sprintf(" (set_id=%s)", set_id);
3285 /* Switch on the result */
3290 if (au->set_id == NULL || set_id != NULL) /* Complete success */
3292 if (set_id != NULL) authenticated_id = string_copy_malloc(set_id);
3293 sender_host_authenticated = au->name;
3294 authentication_failed = FALSE;
3295 authenticated_fail_id = NULL; /* Impossible to already be set? */
3297 protocols[pextend + pauthed + ((tls_in.active >= 0)? pcrpted:0)] +
3298 ((sender_host_address != NULL)? pnlocal : 0);
3299 s = ss = US"235 Authentication succeeded";
3300 authenticated_by = au;
3304 /* Authentication succeeded, but we failed to expand the set_id string.
3305 Treat this as a temporary error. */
3307 auth_defer_msg = expand_string_message;
3311 if (set_id != NULL) authenticated_fail_id = string_copy_malloc(set_id);
3312 s = string_sprintf("435 Unable to authenticate at present%s",
3313 auth_defer_user_msg);
3314 ss = string_sprintf("435 Unable to authenticate at present%s: %s",
3315 set_id, auth_defer_msg);
3319 s = ss = US"501 Invalid base64 data";
3323 s = ss = US"501 Authentication cancelled";
3327 s = ss = US"553 Initial data not expected";
3331 if (set_id != NULL) authenticated_fail_id = string_copy_malloc(set_id);
3332 s = US"535 Incorrect authentication data";
3333 ss = string_sprintf("535 Incorrect authentication data%s", set_id);
3337 if (set_id != NULL) authenticated_fail_id = string_copy_malloc(set_id);
3338 s = US"435 Internal error";
3339 ss = string_sprintf("435 Internal error%s: return %d from authentication "
3340 "check", set_id, c);
3344 smtp_printf("%s\r\n", s);
3346 log_write(0, LOG_MAIN|LOG_REJECT, "%s authenticator failed for %s: %s",
3347 au->name, host_and_ident(FALSE), ss);
3349 break; /* AUTH_CMD */
3351 /* The HELO/EHLO commands are permitted to appear in the middle of a
3352 session as well as at the beginning. They have the effect of a reset in
3353 addition to their other functions. Their absence at the start cannot be
3354 taken to be an error.
3358 If the EHLO command is not acceptable to the SMTP server, 501, 500,
3359 or 502 failure replies MUST be returned as appropriate. The SMTP
3360 server MUST stay in the same state after transmitting these replies
3361 that it was in before the EHLO was received.
3363 Therefore, we do not do the reset until after checking the command for
3364 acceptability. This change was made for Exim release 4.11. Previously
3365 it did the reset first. */
3378 HELO_EHLO: /* Common code for HELO and EHLO */
3379 cmd_list[CMD_LIST_HELO].is_mail_cmd = FALSE;
3380 cmd_list[CMD_LIST_EHLO].is_mail_cmd = FALSE;
3382 /* Reject the HELO if its argument was invalid or non-existent. A
3383 successful check causes the argument to be saved in malloc store. */
3385 if (!check_helo(smtp_cmd_data))
3387 smtp_printf("501 Syntactically invalid %s argument(s)\r\n", hello);
3389 log_write(0, LOG_MAIN|LOG_REJECT, "rejected %s from %s: syntactically "
3390 "invalid argument(s): %s", hello, host_and_ident(FALSE),
3391 (*smtp_cmd_argument == 0)? US"(no argument given)" :
3392 string_printing(smtp_cmd_argument));
3394 if (++synprot_error_count > smtp_max_synprot_errors)
3396 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
3397 "syntax or protocol errors (last command was \"%s\")",
3398 host_and_ident(FALSE), smtp_cmd_buffer);
3405 /* If sender_host_unknown is true, we have got here via the -bs interface,
3406 not called from inetd. Otherwise, we are running an IP connection and the
3407 host address will be set. If the helo name is the primary name of this
3408 host and we haven't done a reverse lookup, force one now. If helo_required
3409 is set, ensure that the HELO name matches the actual host. If helo_verify
3410 is set, do the same check, but softly. */
3412 if (!sender_host_unknown)
3414 BOOL old_helo_verified = helo_verified;
3415 uschar *p = smtp_cmd_data;
3417 while (*p != 0 && !isspace(*p)) { *p = tolower(*p); p++; }
3420 /* Force a reverse lookup if HELO quoted something in helo_lookup_domains
3421 because otherwise the log can be confusing. */
3423 if (sender_host_name == NULL &&
3424 (deliver_domain = sender_helo_name, /* set $domain */
3425 match_isinlist(sender_helo_name, &helo_lookup_domains, 0,
3426 &domainlist_anchor, NULL, MCL_DOMAIN, TRUE, NULL)) == OK)
3427 (void)host_name_lookup();
3429 /* Rebuild the fullhost info to include the HELO name (and the real name
3430 if it was looked up.) */
3432 host_build_sender_fullhost(); /* Rebuild */
3433 set_process_info("handling%s incoming connection from %s",
3434 (tls_in.active >= 0)? " TLS" : "", host_and_ident(FALSE));
3436 /* Verify if configured. This doesn't give much security, but it does
3437 make some people happy to be able to do it. If helo_required is set,
3438 (host matches helo_verify_hosts) failure forces rejection. If helo_verify
3439 is set (host matches helo_try_verify_hosts), it does not. This is perhaps
3440 now obsolescent, since the verification can now be requested selectively
3443 helo_verified = helo_verify_failed = FALSE;
3444 if (helo_required || helo_verify)
3446 BOOL tempfail = !smtp_verify_helo();
3451 smtp_printf("%d %s argument does not match calling host\r\n",
3452 tempfail? 451 : 550, hello);
3453 log_write(0, LOG_MAIN|LOG_REJECT, "%srejected \"%s %s\" from %s",
3454 tempfail? "temporarily " : "",
3455 hello, sender_helo_name, host_and_ident(FALSE));
3456 helo_verified = old_helo_verified;
3457 break; /* End of HELO/EHLO processing */
3459 HDEBUG(D_all) debug_printf("%s verification failed but host is in "
3460 "helo_try_verify_hosts\n", hello);
3465 #ifdef EXPERIMENTAL_SPF
3466 /* set up SPF context */
3467 spf_init(sender_helo_name, sender_host_address);
3470 /* Apply an ACL check if one is defined; afterwards, recheck
3471 synchronization in case the client started sending in a delay. */
3473 if (acl_smtp_helo != NULL)
3475 rc = acl_check(ACL_WHERE_HELO, NULL, acl_smtp_helo, &user_msg, &log_msg);
3478 done = smtp_handle_acl_fail(ACL_WHERE_HELO, rc, user_msg, log_msg);
3479 sender_helo_name = NULL;
3480 host_build_sender_fullhost(); /* Rebuild */
3483 else if (!check_sync()) goto SYNC_FAILURE;
3486 /* Generate an OK reply. The default string includes the ident if present,
3487 and also the IP address if present. Reflecting back the ident is intended
3488 as a deterrent to mail forgers. For maximum efficiency, and also because
3489 some broken systems expect each response to be in a single packet, arrange
3490 that the entire reply is sent in one write(). */
3492 auth_advertised = FALSE;
3493 pipelining_advertised = FALSE;
3495 tls_advertised = FALSE;
3497 #ifdef EXPERIMENTAL_DSN
3498 dsn_advertised = FALSE;
3501 smtp_code = US"250 "; /* Default response code plus space*/
3502 if (user_msg == NULL)
3504 s = string_sprintf("%.3s %s Hello %s%s%s",
3506 smtp_active_hostname,
3507 (sender_ident == NULL)? US"" : sender_ident,
3508 (sender_ident == NULL)? US"" : US" at ",
3509 (sender_host_name == NULL)? sender_helo_name : sender_host_name);
3514 if (sender_host_address != NULL)
3516 s = string_cat(s, &size, &ptr, US" [", 2);
3517 s = string_cat(s, &size, &ptr, sender_host_address,
3518 Ustrlen(sender_host_address));
3519 s = string_cat(s, &size, &ptr, US"]", 1);
3523 /* A user-supplied EHLO greeting may not contain more than one line. Note
3524 that the code returned by smtp_message_code() includes the terminating
3525 whitespace character. */
3531 smtp_message_code(&smtp_code, &codelen, &user_msg, NULL);
3532 s = string_sprintf("%.*s%s", codelen, smtp_code, user_msg);
3533 if ((ss = strpbrk(CS s, "\r\n")) != NULL)
3535 log_write(0, LOG_MAIN|LOG_PANIC, "EHLO/HELO response must not contain "
3536 "newlines: message truncated: %s", string_printing(s));
3543 s = string_cat(s, &size, &ptr, US"\r\n", 2);
3545 /* If we received EHLO, we must create a multiline response which includes
3546 the functions supported. */
3552 /* I'm not entirely happy with this, as an MTA is supposed to check
3553 that it has enough room to accept a message of maximum size before
3554 it sends this. However, there seems little point in not sending it.
3555 The actual size check happens later at MAIL FROM time. By postponing it
3556 till then, VRFY and EXPN can be used after EHLO when space is short. */
3558 if (thismessage_size_limit > 0)
3560 sprintf(CS big_buffer, "%.3s-SIZE %d\r\n", smtp_code,
3561 thismessage_size_limit);
3562 s = string_cat(s, &size, &ptr, big_buffer, Ustrlen(big_buffer));
3566 s = string_cat(s, &size, &ptr, smtp_code, 3);
3567 s = string_cat(s, &size, &ptr, US"-SIZE\r\n", 7);
3570 /* Exim does not do protocol conversion or data conversion. It is 8-bit
3571 clean; if it has an 8-bit character in its hand, it just sends it. It
3572 cannot therefore specify 8BITMIME and remain consistent with the RFCs.
3573 However, some users want this option simply in order to stop MUAs
3574 mangling messages that contain top-bit-set characters. It is therefore
3575 provided as an option. */
3577 if (accept_8bitmime)
3579 s = string_cat(s, &size, &ptr, smtp_code, 3);
3580 s = string_cat(s, &size, &ptr, US"-8BITMIME\r\n", 11);
3583 #ifdef EXPERIMENTAL_DSN
3584 /* Advertise DSN support if configured to do so. */
3585 if (verify_check_host(&dsn_advertise_hosts) != FAIL)
3587 s = string_cat(s, &size, &ptr, smtp_code, 3);
3588 s = string_cat(s, &size, &ptr, US"-DSN\r\n", 6);
3589 dsn_advertised = TRUE;
3593 /* Advertise ETRN if there's an ACL checking whether a host is
3594 permitted to issue it; a check is made when any host actually tries. */
3596 if (acl_smtp_etrn != NULL)
3598 s = string_cat(s, &size, &ptr, smtp_code, 3);
3599 s = string_cat(s, &size, &ptr, US"-ETRN\r\n", 7);
3602 /* Advertise EXPN if there's an ACL checking whether a host is
3603 permitted to issue it; a check is made when any host actually tries. */
3605 if (acl_smtp_expn != NULL)
3607 s = string_cat(s, &size, &ptr, smtp_code, 3);
3608 s = string_cat(s, &size, &ptr, US"-EXPN\r\n", 7);
3611 /* Exim is quite happy with pipelining, so let the other end know that
3612 it is safe to use it, unless advertising is disabled. */
3614 if (pipelining_enable &&
3615 verify_check_host(&pipelining_advertise_hosts) == OK)
3617 s = string_cat(s, &size, &ptr, smtp_code, 3);
3618 s = string_cat(s, &size, &ptr, US"-PIPELINING\r\n", 13);
3619 sync_cmd_limit = NON_SYNC_CMD_PIPELINING;
3620 pipelining_advertised = TRUE;
3624 /* If any server authentication mechanisms are configured, advertise
3625 them if the current host is in auth_advertise_hosts. The problem with
3626 advertising always is that some clients then require users to
3627 authenticate (and aren't configurable otherwise) even though it may not
3628 be necessary (e.g. if the host is in host_accept_relay).
3630 RFC 2222 states that SASL mechanism names contain only upper case
3631 letters, so output the names in upper case, though we actually recognize
3632 them in either case in the AUTH command. */
3636 if (verify_check_host(&auth_advertise_hosts) == OK)
3640 for (au = auths; au != NULL; au = au->next)
3642 if (au->server && (au->advertise_condition == NULL ||
3643 expand_check_condition(au->advertise_condition, au->name,
3644 US"authenticator")))
3649 s = string_cat(s, &size, &ptr, smtp_code, 3);
3650 s = string_cat(s, &size, &ptr, US"-AUTH", 5);
3652 auth_advertised = TRUE;
3655 s = string_cat(s, &size, &ptr, US" ", 1);
3656 s = string_cat(s, &size, &ptr, au->public_name,
3657 Ustrlen(au->public_name));
3658 while (++saveptr < ptr) s[saveptr] = toupper(s[saveptr]);
3659 au->advertised = TRUE;
3661 else au->advertised = FALSE;
3663 if (!first) s = string_cat(s, &size, &ptr, US"\r\n", 2);
3667 /* Advertise TLS (Transport Level Security) aka SSL (Secure Socket Layer)
3668 if it has been included in the binary, and the host matches
3669 tls_advertise_hosts. We must *not* advertise if we are already in a
3670 secure connection. */
3673 if (tls_in.active < 0 &&
3674 verify_check_host(&tls_advertise_hosts) != FAIL)
3676 s = string_cat(s, &size, &ptr, smtp_code, 3);
3677 s = string_cat(s, &size, &ptr, US"-STARTTLS\r\n", 11);
3678 tls_advertised = TRUE;
3682 #ifndef DISABLE_PRDR
3683 /* Per Recipient Data Response, draft by Eric A. Hall extending RFC */
3686 s = string_cat(s, &size, &ptr, smtp_code, 3);
3687 s = string_cat(s, &size, &ptr, US"-PRDR\r\n", 7);
3691 /* Finish off the multiline reply with one that is always available. */
3693 s = string_cat(s, &size, &ptr, smtp_code, 3);
3694 s = string_cat(s, &size, &ptr, US" HELP\r\n", 7);
3697 /* Terminate the string (for debug), write it, and note that HELO/EHLO
3703 if (tls_in.active >= 0) (void)tls_write(TRUE, s, ptr); else
3707 int i = fwrite(s, 1, ptr, smtp_out); i = i; /* compiler quietening */
3712 while ((cr = Ustrchr(s, '\r')) != NULL) /* lose CRs */
3713 memmove(cr, cr + 1, (ptr--) - (cr - s));
3714 debug_printf("SMTP>> %s", s);
3718 /* Reset the protocol and the state, abandoning any previous message. */
3720 received_protocol = (esmtp?
3722 ((sender_host_authenticated != NULL)? pauthed : 0) +
3723 ((tls_in.active >= 0)? pcrpted : 0)]
3725 protocols[pnormal + ((tls_in.active >= 0)? pcrpted : 0)])
3727 ((sender_host_address != NULL)? pnlocal : 0);
3729 smtp_reset(reset_point);
3731 break; /* HELO/EHLO */
3734 /* The MAIL command requires an address as an operand. All we do
3735 here is to parse it for syntactic correctness. The form "<>" is
3736 a special case which converts into an empty string. The start/end
3737 pointers in the original are not used further for this address, as
3738 it is the canonical extracted address which is all that is kept. */
3742 smtp_mailcmd_count++; /* Count for limit and ratelimit */
3743 was_rej_mail = TRUE; /* Reset if accepted */
3744 env_mail_type_t * mail_args; /* Sanity check & validate args */
3746 if (helo_required && !helo_seen)
3748 smtp_printf("503 HELO or EHLO required\r\n");
3749 log_write(0, LOG_MAIN|LOG_REJECT, "rejected MAIL from %s: no "
3750 "HELO/EHLO given", host_and_ident(FALSE));
3754 if (sender_address != NULL)
3756 done = synprot_error(L_smtp_protocol_error, 503, NULL,
3757 US"sender already given");
3761 if (smtp_cmd_data[0] == 0)
3763 done = synprot_error(L_smtp_protocol_error, 501, NULL,
3764 US"MAIL must have an address operand");
3768 /* Check to see if the limit for messages per connection would be
3769 exceeded by accepting further messages. */
3771 if (smtp_accept_max_per_connection > 0 &&
3772 smtp_mailcmd_count > smtp_accept_max_per_connection)
3774 smtp_printf("421 too many messages in this connection\r\n");
3775 log_write(0, LOG_MAIN|LOG_REJECT, "rejected MAIL command %s: too many "
3776 "messages in one connection", host_and_ident(TRUE));
3780 /* Reset for start of message - even if this is going to fail, we
3781 obviously need to throw away any previous data. */
3783 smtp_reset(reset_point);
3785 sender_data = recipient_data = NULL;
3787 /* Loop, checking for ESMTP additions to the MAIL FROM command. */
3791 uschar *name, *value, *end;
3792 unsigned long int size;
3793 BOOL arg_error = FALSE;
3795 if (!extract_option(&name, &value)) break;
3797 for (mail_args = env_mail_type_list;
3798 (char *)mail_args < (char *)env_mail_type_list + sizeof(env_mail_type_list);
3802 if (strcmpic(name, mail_args->name) == 0)
3805 if (mail_args->need_value && strcmpic(value, US"") == 0)
3808 switch(mail_args->value)
3810 /* Handle SIZE= by reading the value. We don't do the check till later,
3811 in order to be able to log the sender address on failure. */
3812 case ENV_MAIL_OPT_SIZE:
3813 if (((size = Ustrtoul(value, &end, 10)), *end == 0))
3815 if ((size == ULONG_MAX && errno == ERANGE) || size > INT_MAX)
3817 message_size = (int)size;
3823 /* If this session was initiated with EHLO and accept_8bitmime is set,
3824 Exim will have indicated that it supports the BODY=8BITMIME option. In
3825 fact, it does not support this according to the RFCs, in that it does not
3826 take any special action for forwarding messages containing 8-bit
3827 characters. That is why accept_8bitmime is not the default setting, but
3828 some sites want the action that is provided. We recognize both "8BITMIME"
3829 and "7BIT" as body types, but take no action. */
3830 case ENV_MAIL_OPT_BODY:
3831 if (accept_8bitmime) {
3832 if (strcmpic(value, US"8BITMIME") == 0) {
3834 } else if (strcmpic(value, US"7BIT") == 0) {
3838 done = synprot_error(L_smtp_syntax_error, 501, NULL,
3839 US"invalid data for BODY");
3842 DEBUG(D_receive) debug_printf("8BITMIME: %d\n", body_8bitmime);
3848 #ifdef EXPERIMENTAL_DSN
3850 /* Handle the two DSN options, but only if configured to do so (which
3851 will have caused "DSN" to be given in the EHLO response). The code itself
3852 is included only if configured in at build time. */
3854 case ENV_MAIL_OPT_RET:
3855 if (dsn_advertised) {
3856 /* Check if RET has already been set */
3858 synprot_error(L_smtp_syntax_error, 501, NULL,
3859 US"RET can be specified once only");
3862 dsn_ret = (strcmpic(value, US"HDRS") == 0)? dsn_ret_hdrs :
3863 (strcmpic(value, US"FULL") == 0)? dsn_ret_full : 0;
3864 DEBUG(D_receive) debug_printf("DSN_RET: %d\n", dsn_ret);
3865 /* Check for invalid invalid value, and exit with error */
3867 synprot_error(L_smtp_syntax_error, 501, NULL,
3868 US"Value for RET is invalid");
3873 case ENV_MAIL_OPT_ENVID:
3874 if (dsn_advertised) {
3875 /* Check if the dsn envid has been already set */
3876 if (dsn_envid != NULL) {
3877 synprot_error(L_smtp_syntax_error, 501, NULL,
3878 US"ENVID can be specified once only");
3881 dsn_envid = string_copy(value);
3882 DEBUG(D_receive) debug_printf("DSN_ENVID: %s\n", dsn_envid);
3887 /* Handle the AUTH extension. If the value given is not "<>" and either
3888 the ACL says "yes" or there is no ACL but the sending host is
3889 authenticated, we set it up as the authenticated sender. However, if the
3890 authenticator set a condition to be tested, we ignore AUTH on MAIL unless
3891 the condition is met. The value of AUTH is an xtext, which means that +,
3892 = and cntrl chars are coded in hex; however "<>" is unaffected by this
3894 case ENV_MAIL_OPT_AUTH:
3895 if (Ustrcmp(value, "<>") != 0)
3900 if (auth_xtextdecode(value, &authenticated_sender) < 0)
3902 /* Put back terminator overrides for error message */
3905 done = synprot_error(L_smtp_syntax_error, 501, NULL,
3906 US"invalid data for AUTH");
3909 if (acl_smtp_mailauth == NULL)
3911 ignore_msg = US"client not authenticated";
3912 rc = (sender_host_authenticated != NULL)? OK : FAIL;
3916 ignore_msg = US"rejected by ACL";
3917 rc = acl_check(ACL_WHERE_MAILAUTH, NULL, acl_smtp_mailauth,
3918 &user_msg, &log_msg);
3924 if (authenticated_by == NULL ||
3925 authenticated_by->mail_auth_condition == NULL ||
3926 expand_check_condition(authenticated_by->mail_auth_condition,
3927 authenticated_by->name, US"authenticator"))
3928 break; /* Accept the AUTH */
3930 ignore_msg = US"server_mail_auth_condition failed";
3931 if (authenticated_id != NULL)
3932 ignore_msg = string_sprintf("%s: authenticated ID=\"%s\"",
3933 ignore_msg, authenticated_id);
3938 authenticated_sender = NULL;
3939 log_write(0, LOG_MAIN, "ignoring AUTH=%s from %s (%s)",
3940 value, host_and_ident(TRUE), ignore_msg);
3943 /* Should only get DEFER or ERROR here. Put back terminator
3944 overrides for error message */
3949 (void)smtp_handle_acl_fail(ACL_WHERE_MAILAUTH, rc, user_msg,
3956 #ifndef DISABLE_PRDR
3957 case ENV_MAIL_OPT_PRDR:
3959 prdr_requested = TRUE;
3963 /* Unknown option. Stick back the terminator characters and break
3964 the loop. Do the name-terminator second as extract_option sets
3965 value==name when it found no equal-sign.
3966 An error for a malformed address will occur. */
3973 /* Break out of for loop if switch() had bad argument or
3974 when start of the email address is reached */
3975 if (arg_error) break;
3978 /* If we have passed the threshold for rate limiting, apply the current
3979 delay, and update it for next time, provided this is a limited host. */
3981 if (smtp_mailcmd_count > smtp_rlm_threshold &&
3982 verify_check_host(&smtp_ratelimit_hosts) == OK)
3984 DEBUG(D_receive) debug_printf("rate limit MAIL: delay %.3g sec\n",
3985 smtp_delay_mail/1000.0);
3986 millisleep((int)smtp_delay_mail);
3987 smtp_delay_mail *= smtp_rlm_factor;
3988 if (smtp_delay_mail > (double)smtp_rlm_limit)
3989 smtp_delay_mail = (double)smtp_rlm_limit;
3992 /* Now extract the address, first applying any SMTP-time rewriting. The
3993 TRUE flag allows "<>" as a sender address. */
3995 raw_sender = ((rewrite_existflags & rewrite_smtp) != 0)?
3996 rewrite_one(smtp_cmd_data, rewrite_smtp, NULL, FALSE, US"",
3997 global_rewrite_rules) : smtp_cmd_data;
3999 /* rfc821_domains = TRUE; << no longer needed */
4001 parse_extract_address(raw_sender, &errmess, &start, &end, &sender_domain,
4003 /* rfc821_domains = FALSE; << no longer needed */
4005 if (raw_sender == NULL)
4007 done = synprot_error(L_smtp_syntax_error, 501, smtp_cmd_data, errmess);
4011 sender_address = raw_sender;
4013 /* If there is a configured size limit for mail, check that this message
4014 doesn't exceed it. The check is postponed to this point so that the sender
4017 if (thismessage_size_limit > 0 && message_size > thismessage_size_limit)
4019 smtp_printf("552 Message size exceeds maximum permitted\r\n");
4020 log_write(L_size_reject,
4021 LOG_MAIN|LOG_REJECT, "rejected MAIL FROM:<%s> %s: "
4022 "message too big: size%s=%d max=%d",
4024 host_and_ident(TRUE),
4025 (message_size == INT_MAX)? ">" : "",
4027 thismessage_size_limit);
4028 sender_address = NULL;
4032 /* Check there is enough space on the disk unless configured not to.
4033 When smtp_check_spool_space is set, the check is for thismessage_size_limit
4034 plus the current message - i.e. we accept the message only if it won't
4035 reduce the space below the threshold. Add 5000 to the size to allow for
4036 overheads such as the Received: line and storing of recipients, etc.
4037 By putting the check here, even when SIZE is not given, it allow VRFY
4038 and EXPN etc. to be used when space is short. */
4040 if (!receive_check_fs(
4041 (smtp_check_spool_space && message_size >= 0)?
4042 message_size + 5000 : 0))
4044 smtp_printf("452 Space shortage, please try later\r\n");
4045 sender_address = NULL;
4049 /* If sender_address is unqualified, reject it, unless this is a locally
4050 generated message, or the sending host or net is permitted to send
4051 unqualified addresses - typically local machines behaving as MUAs -
4052 in which case just qualify the address. The flag is set above at the start
4053 of the SMTP connection. */
4055 if (sender_domain == 0 && sender_address[0] != 0)
4057 if (allow_unqualified_sender)
4059 sender_domain = Ustrlen(sender_address) + 1;
4060 sender_address = rewrite_address_qualify(sender_address, FALSE);
4061 DEBUG(D_receive) debug_printf("unqualified address %s accepted\n",
4066 smtp_printf("501 %s: sender address must contain a domain\r\n",
4068 log_write(L_smtp_syntax_error,
4069 LOG_MAIN|LOG_REJECT,
4070 "unqualified sender rejected: <%s> %s%s",
4072 host_and_ident(TRUE),
4074 sender_address = NULL;
4079 /* Apply an ACL check if one is defined, before responding. Afterwards,
4080 when pipelining is not advertised, do another sync check in case the ACL
4081 delayed and the client started sending in the meantime. */
4085 rc = acl_check(ACL_WHERE_MAIL, NULL, acl_smtp_mail, &user_msg, &log_msg);
4086 if (rc == OK && !pipelining_advertised && !check_sync())
4092 if (rc == OK || rc == DISCARD)
4095 smtp_printf("%s%s%s", US"250 OK",
4096 #ifndef DISABLE_PRDR
4097 prdr_requested ? US", PRDR Requested" : US"",
4104 #ifndef DISABLE_PRDR
4106 user_msg = string_sprintf("%s%s", user_msg, US", PRDR Requested");
4108 smtp_user_msg(US"250", user_msg);
4110 smtp_delay_rcpt = smtp_rlr_base;
4111 recipients_discarded = (rc == DISCARD);
4112 was_rej_mail = FALSE;
4116 done = smtp_handle_acl_fail(ACL_WHERE_MAIL, rc, user_msg, log_msg);
4117 sender_address = NULL;
4122 /* The RCPT command requires an address as an operand. There may be any
4123 number of RCPT commands, specifying multiple recipients. We build them all
4124 into a data structure. The start/end values given by parse_extract_address
4125 are not used, as we keep only the extracted address. */
4130 was_rcpt = rcpt_in_progress = TRUE;
4132 /* There must be a sender address; if the sender was rejected and
4133 pipelining was advertised, we assume the client was pipelining, and do not
4134 count this as a protocol error. Reset was_rej_mail so that further RCPTs
4135 get the same treatment. */
4137 if (sender_address == NULL)
4139 if (pipelining_advertised && last_was_rej_mail)
4141 smtp_printf("503 sender not yet given\r\n");
4142 was_rej_mail = TRUE;
4146 done = synprot_error(L_smtp_protocol_error, 503, NULL,
4147 US"sender not yet given");
4148 was_rcpt = FALSE; /* Not a valid RCPT */
4154 /* Check for an operand */
4156 if (smtp_cmd_data[0] == 0)
4158 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4159 US"RCPT must have an address operand");
4164 #ifdef EXPERIMENTAL_DSN
4165 /* Set the DSN flags orcpt and dsn_flags from the session*/
4171 uschar *name, *value, *end;
4174 if (!extract_option(&name, &value))
4179 if (dsn_advertised && strcmpic(name, US"ORCPT") == 0)
4181 /* Check whether orcpt has been already set */
4182 if (orcpt != NULL) {
4183 synprot_error(L_smtp_syntax_error, 501, NULL,
4184 US"ORCPT can be specified once only");
4187 orcpt = string_copy(value);
4188 DEBUG(D_receive) debug_printf("DSN orcpt: %s\n", orcpt);
4191 else if (dsn_advertised && strcmpic(name, US"NOTIFY") == 0)
4193 /* Check if the notify flags have been already set */
4195 synprot_error(L_smtp_syntax_error, 501, NULL,
4196 US"NOTIFY can be specified once only");
4199 if (strcmpic(value, US"NEVER") == 0) flags |= rf_notify_never; else
4205 while (*pp != 0 && *pp != ',') pp++;
4206 if (*pp == ',') *pp++ = 0;
4207 if (strcmpic(p, US"SUCCESS") == 0) {
4208 DEBUG(D_receive) debug_printf("DSN: Setting notify success\n");
4209 flags |= rf_notify_success;
4211 else if (strcmpic(p, US"FAILURE") == 0) {
4212 DEBUG(D_receive) debug_printf("DSN: Setting notify failure\n");
4213 flags |= rf_notify_failure;
4215 else if (strcmpic(p, US"DELAY") == 0) {
4216 DEBUG(D_receive) debug_printf("DSN: Setting notify delay\n");
4217 flags |= rf_notify_delay;
4220 /* Catch any strange values */
4221 synprot_error(L_smtp_syntax_error, 501, NULL,
4222 US"Invalid value for NOTIFY parameter");
4227 DEBUG(D_receive) debug_printf("DSN Flags: %x\n", flags);
4231 /* Unknown option. Stick back the terminator characters and break
4232 the loop. An error for a malformed address will occur. */
4236 DEBUG(D_receive) debug_printf("Invalid RCPT option: %s : %s\n", name, value);
4244 /* Apply SMTP rewriting then extract the working address. Don't allow "<>"
4245 as a recipient address */
4247 recipient = ((rewrite_existflags & rewrite_smtp) != 0)?
4248 rewrite_one(smtp_cmd_data, rewrite_smtp, NULL, FALSE, US"",
4249 global_rewrite_rules) : smtp_cmd_data;
4251 /* rfc821_domains = TRUE; << no longer needed */
4252 recipient = parse_extract_address(recipient, &errmess, &start, &end,
4253 &recipient_domain, FALSE);
4254 /* rfc821_domains = FALSE; << no longer needed */
4256 if (recipient == NULL)
4258 done = synprot_error(L_smtp_syntax_error, 501, smtp_cmd_data, errmess);
4263 /* If the recipient address is unqualified, reject it, unless this is a
4264 locally generated message. However, unqualified addresses are permitted
4265 from a configured list of hosts and nets - typically when behaving as
4266 MUAs rather than MTAs. Sad that SMTP is used for both types of traffic,
4267 really. The flag is set at the start of the SMTP connection.
4269 RFC 1123 talks about supporting "the reserved mailbox postmaster"; I always
4270 assumed this meant "reserved local part", but the revision of RFC 821 and
4271 friends now makes it absolutely clear that it means *mailbox*. Consequently
4272 we must always qualify this address, regardless. */
4274 if (recipient_domain == 0)
4276 if (allow_unqualified_recipient ||
4277 strcmpic(recipient, US"postmaster") == 0)
4279 DEBUG(D_receive) debug_printf("unqualified address %s accepted\n",
4281 recipient_domain = Ustrlen(recipient) + 1;
4282 recipient = rewrite_address_qualify(recipient, TRUE);
4287 smtp_printf("501 %s: recipient address must contain a domain\r\n",
4289 log_write(L_smtp_syntax_error,
4290 LOG_MAIN|LOG_REJECT, "unqualified recipient rejected: "
4291 "<%s> %s%s", recipient, host_and_ident(TRUE),
4297 /* Check maximum allowed */
4299 if (rcpt_count > recipients_max && recipients_max > 0)
4301 if (recipients_max_reject)
4304 smtp_printf("552 too many recipients\r\n");
4306 log_write(0, LOG_MAIN|LOG_REJECT, "too many recipients: message "
4307 "rejected: sender=<%s> %s", sender_address, host_and_ident(TRUE));
4312 smtp_printf("452 too many recipients\r\n");
4314 log_write(0, LOG_MAIN|LOG_REJECT, "too many recipients: excess "
4315 "temporarily rejected: sender=<%s> %s", sender_address,
4316 host_and_ident(TRUE));
4323 /* If we have passed the threshold for rate limiting, apply the current
4324 delay, and update it for next time, provided this is a limited host. */
4326 if (rcpt_count > smtp_rlr_threshold &&
4327 verify_check_host(&smtp_ratelimit_hosts) == OK)
4329 DEBUG(D_receive) debug_printf("rate limit RCPT: delay %.3g sec\n",
4330 smtp_delay_rcpt/1000.0);
4331 millisleep((int)smtp_delay_rcpt);
4332 smtp_delay_rcpt *= smtp_rlr_factor;
4333 if (smtp_delay_rcpt > (double)smtp_rlr_limit)
4334 smtp_delay_rcpt = (double)smtp_rlr_limit;
4337 /* If the MAIL ACL discarded all the recipients, we bypass ACL checking
4338 for them. Otherwise, check the access control list for this recipient. As
4339 there may be a delay in this, re-check for a synchronization error
4340 afterwards, unless pipelining was advertised. */
4342 if (recipients_discarded) rc = DISCARD; else
4344 rc = acl_check(ACL_WHERE_RCPT, recipient, acl_smtp_rcpt, &user_msg,
4346 if (rc == OK && !pipelining_advertised && !check_sync())
4350 /* The ACL was happy */
4354 if (user_msg == NULL) smtp_printf("250 Accepted\r\n");
4355 else smtp_user_msg(US"250", user_msg);
4356 receive_add_recipient(recipient, -1);
4358 #ifdef EXPERIMENTAL_DSN
4359 /* Set the dsn flags in the recipients_list */
4361 recipients_list[recipients_count-1].orcpt = orcpt;
4363 recipients_list[recipients_count-1].orcpt = NULL;
4366 recipients_list[recipients_count-1].dsn_flags = flags;
4368 recipients_list[recipients_count-1].dsn_flags = 0;
4369 DEBUG(D_receive) debug_printf("DSN: orcpt: %s flags: %d\n", recipients_list[recipients_count-1].orcpt, recipients_list[recipients_count-1].dsn_flags);
4374 /* The recipient was discarded */
4376 else if (rc == DISCARD)
4378 if (user_msg == NULL) smtp_printf("250 Accepted\r\n");
4379 else smtp_user_msg(US"250", user_msg);
4382 log_write(0, LOG_MAIN|LOG_REJECT, "%s F=<%s> rejected RCPT %s: "
4383 "discarded by %s ACL%s%s", host_and_ident(TRUE),
4384 (sender_address_unrewritten != NULL)?
4385 sender_address_unrewritten : sender_address,
4386 smtp_cmd_argument, recipients_discarded? "MAIL" : "RCPT",
4387 (log_msg == NULL)? US"" : US": ",
4388 (log_msg == NULL)? US"" : log_msg);
4391 /* Either the ACL failed the address, or it was deferred. */
4395 if (rc == FAIL) rcpt_fail_count++; else rcpt_defer_count++;
4396 done = smtp_handle_acl_fail(ACL_WHERE_RCPT, rc, user_msg, log_msg);
4401 /* The DATA command is legal only if it follows successful MAIL FROM
4402 and RCPT TO commands. However, if pipelining is advertised, a bad DATA is
4403 not counted as a protocol error if it follows RCPT (which must have been
4404 rejected if there are no recipients.) This function is complete when a
4405 valid DATA command is encountered.
4407 Note concerning the code used: RFC 2821 says this:
4409 - If there was no MAIL, or no RCPT, command, or all such commands
4410 were rejected, the server MAY return a "command out of sequence"
4411 (503) or "no valid recipients" (554) reply in response to the
4414 The example in the pipelining RFC 2920 uses 554, but I use 503 here
4415 because it is the same whether pipelining is in use or not.
4417 If all the RCPT commands that precede DATA provoked the same error message
4418 (often indicating some kind of system error), it is helpful to include it
4419 with the DATA rejection (an idea suggested by Tony Finch). */
4423 if (!discarded && recipients_count <= 0)
4425 if (rcpt_smtp_response_same && rcpt_smtp_response != NULL)
4427 uschar *code = US"503";
4428 int len = Ustrlen(rcpt_smtp_response);
4429 smtp_respond(code, 3, FALSE, US"All RCPT commands were rejected with "
4431 /* Responses from smtp_printf() will have \r\n on the end */
4432 if (len > 2 && rcpt_smtp_response[len-2] == '\r')
4433 rcpt_smtp_response[len-2] = 0;
4434 smtp_respond(code, 3, FALSE, rcpt_smtp_response);
4436 if (pipelining_advertised && last_was_rcpt)
4437 smtp_printf("503 Valid RCPT command must precede DATA\r\n");
4439 done = synprot_error(L_smtp_protocol_error, 503, NULL,
4440 US"valid RCPT command must precede DATA");
4444 if (toomany && recipients_max_reject)
4446 sender_address = NULL; /* This will allow a new MAIL without RSET */
4447 sender_address_unrewritten = NULL;
4448 smtp_printf("554 Too many recipients\r\n");
4452 /* If there is an ACL, re-check the synchronization afterwards, since the
4453 ACL may have delayed. To handle cutthrough delivery enforce a dummy call
4454 to get the DATA command sent. */
4456 if (acl_smtp_predata == NULL && cutthrough_fd < 0) rc = OK; else
4458 uschar * acl= acl_smtp_predata ? acl_smtp_predata : US"accept";
4459 enable_dollar_recipients = TRUE;
4460 rc = acl_check(ACL_WHERE_PREDATA, NULL, acl, &user_msg,
4462 enable_dollar_recipients = FALSE;
4463 if (rc == OK && !check_sync()) goto SYNC_FAILURE;
4470 if (user_msg == NULL)
4471 smtp_printf("%s Enter message, ending with \".\" on a line by itself\r\n", code);
4472 else smtp_user_msg(code, user_msg);
4474 message_ended = END_NOTENDED; /* Indicate in middle of data */
4477 /* Either the ACL failed the address, or it was deferred. */
4480 done = smtp_handle_acl_fail(ACL_WHERE_PREDATA, rc, user_msg, log_msg);
4486 rc = acl_check(ACL_WHERE_VRFY, NULL, acl_smtp_vrfy, &user_msg, &log_msg);
4488 done = smtp_handle_acl_fail(ACL_WHERE_VRFY, rc, user_msg, log_msg);
4494 /* rfc821_domains = TRUE; << no longer needed */
4495 address = parse_extract_address(smtp_cmd_data, &errmess, &start, &end,
4496 &recipient_domain, FALSE);
4497 /* rfc821_domains = FALSE; << no longer needed */
4499 if (address == NULL)
4500 s = string_sprintf("501 %s", errmess);
4503 address_item *addr = deliver_make_addr(address, FALSE);
4504 switch(verify_address(addr, NULL, vopt_is_recipient | vopt_qualify, -1,
4505 -1, -1, NULL, NULL, NULL))
4508 s = string_sprintf("250 <%s> is deliverable", address);
4512 s = (addr->user_message != NULL)?
4513 string_sprintf("451 <%s> %s", address, addr->user_message) :
4514 string_sprintf("451 Cannot resolve <%s> at this time", address);
4518 s = (addr->user_message != NULL)?
4519 string_sprintf("550 <%s> %s", address, addr->user_message) :
4520 string_sprintf("550 <%s> is not deliverable", address);
4521 log_write(0, LOG_MAIN, "VRFY failed for %s %s",
4522 smtp_cmd_argument, host_and_ident(TRUE));
4527 smtp_printf("%s\r\n", s);
4534 rc = acl_check(ACL_WHERE_EXPN, NULL, acl_smtp_expn, &user_msg, &log_msg);
4536 done = smtp_handle_acl_fail(ACL_WHERE_EXPN, rc, user_msg, log_msg);
4539 BOOL save_log_testing_mode = log_testing_mode;
4540 address_test_mode = log_testing_mode = TRUE;
4541 (void) verify_address(deliver_make_addr(smtp_cmd_data, FALSE),
4542 smtp_out, vopt_is_recipient | vopt_qualify | vopt_expn, -1, -1, -1,
4544 address_test_mode = FALSE;
4545 log_testing_mode = save_log_testing_mode; /* true for -bh */
4554 if (!tls_advertised)
4556 done = synprot_error(L_smtp_protocol_error, 503, NULL,
4557 US"STARTTLS command used when not advertised");
4561 /* Apply an ACL check if one is defined */
4563 if (acl_smtp_starttls != NULL)
4565 rc = acl_check(ACL_WHERE_STARTTLS, NULL, acl_smtp_starttls, &user_msg,
4569 done = smtp_handle_acl_fail(ACL_WHERE_STARTTLS, rc, user_msg, log_msg);
4574 /* RFC 2487 is not clear on when this command may be sent, though it
4575 does state that all information previously obtained from the client
4576 must be discarded if a TLS session is started. It seems reasonble to
4577 do an implied RSET when STARTTLS is received. */
4579 incomplete_transaction_log(US"STARTTLS");
4580 smtp_reset(reset_point);
4582 cmd_list[CMD_LIST_STARTTLS].is_mail_cmd = FALSE;
4584 /* There's an attack where more data is read in past the STARTTLS command
4585 before TLS is negotiated, then assumed to be part of the secure session
4586 when used afterwards; we use segregated input buffers, so are not
4587 vulnerable, but we want to note when it happens and, for sheer paranoia,
4588 ensure that the buffer is "wiped".
4589 Pipelining sync checks will normally have protected us too, unless disabled
4590 by configuration. */
4592 if (receive_smtp_buffered())
4595 debug_printf("Non-empty input buffer after STARTTLS; naive attack?");
4596 if (tls_in.active < 0)
4597 smtp_inend = smtp_inptr = smtp_inbuffer;
4598 /* and if TLS is already active, tls_server_start() should fail */
4601 /* There is nothing we value in the input buffer and if TLS is succesfully
4602 negotiated, we won't use this buffer again; if TLS fails, we'll just read
4603 fresh content into it. The buffer contains arbitrary content from an
4604 untrusted remote source; eg: NOOP <shellcode>\r\nSTARTTLS\r\n
4605 It seems safest to just wipe away the content rather than leave it as a
4606 target to jump to. */
4608 memset(smtp_inbuffer, 0, in_buffer_size);
4610 /* Attempt to start up a TLS session, and if successful, discard all
4611 knowledge that was obtained previously. At least, that's what the RFC says,
4612 and that's what happens by default. However, in order to work round YAEB,
4613 there is an option to remember the esmtp state. Sigh.
4615 We must allow for an extra EHLO command and an extra AUTH command after
4616 STARTTLS that don't add to the nonmail command count. */
4618 if ((rc = tls_server_start(tls_require_ciphers)) == OK)
4620 if (!tls_remember_esmtp)
4621 helo_seen = esmtp = auth_advertised = pipelining_advertised = FALSE;
4622 cmd_list[CMD_LIST_EHLO].is_mail_cmd = TRUE;
4623 cmd_list[CMD_LIST_AUTH].is_mail_cmd = TRUE;
4624 if (sender_helo_name != NULL)
4626 store_free(sender_helo_name);
4627 sender_helo_name = NULL;
4628 host_build_sender_fullhost(); /* Rebuild */
4629 set_process_info("handling incoming TLS connection from %s",
4630 host_and_ident(FALSE));
4632 received_protocol = (esmtp?
4633 protocols[pextend + pcrpted +
4634 ((sender_host_authenticated != NULL)? pauthed : 0)]
4636 protocols[pnormal + pcrpted])
4638 ((sender_host_address != NULL)? pnlocal : 0);
4640 sender_host_authenticated = NULL;
4641 authenticated_id = NULL;
4642 sync_cmd_limit = NON_SYNC_CMD_NON_PIPELINING;
4643 DEBUG(D_tls) debug_printf("TLS active\n");
4644 break; /* Successful STARTTLS */
4647 /* Some local configuration problem was discovered before actually trying
4648 to do a TLS handshake; give a temporary error. */
4650 else if (rc == DEFER)
4652 smtp_printf("454 TLS currently unavailable\r\n");
4656 /* Hard failure. Reject everything except QUIT or closed connection. One
4657 cause for failure is a nested STARTTLS, in which case tls_in.active remains
4658 set, but we must still reject all incoming commands. */
4660 DEBUG(D_tls) debug_printf("TLS failed to start\n");
4663 switch(smtp_read_command(FALSE))
4666 log_write(L_smtp_connection, LOG_MAIN, "%s closed by EOF",
4667 smtp_get_connection_info());
4668 smtp_notquit_exit(US"tls-failed", NULL, NULL);
4672 /* It is perhaps arguable as to which exit ACL should be called here,
4673 but as it is probably a situation that almost never arises, it
4674 probably doesn't matter. We choose to call the real QUIT ACL, which in
4675 some sense is perhaps "right". */
4679 if (acl_smtp_quit != NULL)
4681 rc = acl_check(ACL_WHERE_QUIT, NULL, acl_smtp_quit, &user_msg,
4684 log_write(0, LOG_MAIN|LOG_PANIC, "ACL for QUIT returned ERROR: %s",
4687 if (user_msg == NULL)
4688 smtp_printf("221 %s closing connection\r\n", smtp_active_hostname);
4690 smtp_respond(US"221", 3, TRUE, user_msg);
4691 log_write(L_smtp_connection, LOG_MAIN, "%s closed by QUIT",
4692 smtp_get_connection_info());
4697 smtp_printf("554 Security failure\r\n");
4701 tls_close(TRUE, TRUE);
4706 /* The ACL for QUIT is provided for gathering statistical information or
4707 similar; it does not affect the response code, but it can supply a custom
4712 incomplete_transaction_log(US"QUIT");
4713 if (acl_smtp_quit != NULL)
4715 rc = acl_check(ACL_WHERE_QUIT, NULL, acl_smtp_quit, &user_msg, &log_msg);
4717 log_write(0, LOG_MAIN|LOG_PANIC, "ACL for QUIT returned ERROR: %s",
4720 if (user_msg == NULL)
4721 smtp_printf("221 %s closing connection\r\n", smtp_active_hostname);
4723 smtp_respond(US"221", 3, TRUE, user_msg);
4726 tls_close(TRUE, TRUE);
4730 log_write(L_smtp_connection, LOG_MAIN, "%s closed by QUIT",
4731 smtp_get_connection_info());
4737 incomplete_transaction_log(US"RSET");
4738 smtp_reset(reset_point);
4740 smtp_printf("250 Reset OK\r\n");
4741 cmd_list[CMD_LIST_RSET].is_mail_cmd = FALSE;
4747 smtp_printf("250 OK\r\n");
4751 /* Show ETRN/EXPN/VRFY if there's an ACL for checking hosts; if actually
4752 used, a check will be done for permitted hosts. Show STARTTLS only if not
4753 already in a TLS session and if it would be advertised in the EHLO
4758 smtp_printf("214-Commands supported:\r\n");
4762 Ustrcat(buffer, " AUTH");
4764 if (tls_in.active < 0 &&
4765 verify_check_host(&tls_advertise_hosts) != FAIL)
4766 Ustrcat(buffer, " STARTTLS");
4768 Ustrcat(buffer, " HELO EHLO MAIL RCPT DATA");
4769 Ustrcat(buffer, " NOOP QUIT RSET HELP");
4770 if (acl_smtp_etrn != NULL) Ustrcat(buffer, " ETRN");
4771 if (acl_smtp_expn != NULL) Ustrcat(buffer, " EXPN");
4772 if (acl_smtp_vrfy != NULL) Ustrcat(buffer, " VRFY");
4773 smtp_printf("214%s\r\n", buffer);
4779 incomplete_transaction_log(US"connection lost");
4780 smtp_notquit_exit(US"connection-lost", US"421",
4781 US"%s lost input connection", smtp_active_hostname);
4783 /* Don't log by default unless in the middle of a message, as some mailers
4784 just drop the call rather than sending QUIT, and it clutters up the logs.
4787 if (sender_address != NULL || recipients_count > 0)
4788 log_write(L_lost_incoming_connection,
4790 "unexpected %s while reading SMTP command from %s%s",
4791 sender_host_unknown? "EOF" : "disconnection",
4792 host_and_ident(FALSE), smtp_read_error);
4794 else log_write(L_smtp_connection, LOG_MAIN, "%s lost%s",
4795 smtp_get_connection_info(), smtp_read_error);
4803 if (sender_address != NULL)
4805 done = synprot_error(L_smtp_protocol_error, 503, NULL,
4806 US"ETRN is not permitted inside a transaction");
4810 log_write(L_etrn, LOG_MAIN, "ETRN %s received from %s", smtp_cmd_argument,
4811 host_and_ident(FALSE));
4813 rc = acl_check(ACL_WHERE_ETRN, NULL, acl_smtp_etrn, &user_msg, &log_msg);
4816 done = smtp_handle_acl_fail(ACL_WHERE_ETRN, rc, user_msg, log_msg);
4820 /* Compute the serialization key for this command. */
4822 etrn_serialize_key = string_sprintf("etrn-%s\n", smtp_cmd_data);
4824 /* If a command has been specified for running as a result of ETRN, we
4825 permit any argument to ETRN. If not, only the # standard form is permitted,
4826 since that is strictly the only kind of ETRN that can be implemented
4827 according to the RFC. */
4829 if (smtp_etrn_command != NULL)
4833 etrn_command = smtp_etrn_command;
4834 deliver_domain = smtp_cmd_data;
4835 rc = transport_set_up_command(&argv, smtp_etrn_command, TRUE, 0, NULL,
4836 US"ETRN processing", &error);
4837 deliver_domain = NULL;
4840 log_write(0, LOG_MAIN|LOG_PANIC, "failed to set up ETRN command: %s",
4842 smtp_printf("458 Internal failure\r\n");
4847 /* Else set up to call Exim with the -R option. */
4851 if (*smtp_cmd_data++ != '#')
4853 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4854 US"argument must begin with #");
4857 etrn_command = US"exim -R";
4858 argv = child_exec_exim(CEE_RETURN_ARGV, TRUE, NULL, TRUE, 2, US"-R",
4862 /* If we are host-testing, don't actually do anything. */
4868 debug_printf("ETRN command is: %s\n", etrn_command);
4869 debug_printf("ETRN command execution skipped\n");
4871 if (user_msg == NULL) smtp_printf("250 OK\r\n");
4872 else smtp_user_msg(US"250", user_msg);
4877 /* If ETRN queue runs are to be serialized, check the database to
4878 ensure one isn't already running. */
4880 if (smtp_etrn_serialize && !enq_start(etrn_serialize_key))
4882 smtp_printf("458 Already processing %s\r\n", smtp_cmd_data);
4886 /* Fork a child process and run the command. We don't want to have to
4887 wait for the process at any point, so set SIGCHLD to SIG_IGN before
4888 forking. It should be set that way anyway for external incoming SMTP,
4889 but we save and restore to be tidy. If serialization is required, we
4890 actually run the command in yet another process, so we can wait for it
4891 to complete and then remove the serialization lock. */
4893 oldsignal = signal(SIGCHLD, SIG_IGN);
4895 if ((pid = fork()) == 0)
4897 smtp_input = FALSE; /* This process is not associated with the */
4898 (void)fclose(smtp_in); /* SMTP call any more. */
4899 (void)fclose(smtp_out);
4901 signal(SIGCHLD, SIG_DFL); /* Want to catch child */
4903 /* If not serializing, do the exec right away. Otherwise, fork down
4904 into another process. */
4906 if (!smtp_etrn_serialize || (pid = fork()) == 0)
4908 DEBUG(D_exec) debug_print_argv(argv);
4909 exim_nullstd(); /* Ensure std{in,out,err} exist */
4910 execv(CS argv[0], (char *const *)argv);
4911 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "exec of \"%s\" (ETRN) failed: %s",
4912 etrn_command, strerror(errno));
4913 _exit(EXIT_FAILURE); /* paranoia */
4916 /* Obey this if smtp_serialize and the 2nd fork yielded non-zero. That
4917 is, we are in the first subprocess, after forking again. All we can do
4918 for a failing fork is to log it. Otherwise, wait for the 2nd process to
4919 complete, before removing the serialization. */
4922 log_write(0, LOG_MAIN|LOG_PANIC, "2nd fork for serialized ETRN "
4923 "failed: %s", strerror(errno));
4927 DEBUG(D_any) debug_printf("waiting for serialized ETRN process %d\n",
4929 (void)wait(&status);
4930 DEBUG(D_any) debug_printf("serialized ETRN process %d ended\n",
4934 enq_end(etrn_serialize_key);
4935 _exit(EXIT_SUCCESS);
4938 /* Back in the top level SMTP process. Check that we started a subprocess
4939 and restore the signal state. */
4943 log_write(0, LOG_MAIN|LOG_PANIC, "fork of process for ETRN failed: %s",
4945 smtp_printf("458 Unable to fork process\r\n");
4946 if (smtp_etrn_serialize) enq_end(etrn_serialize_key);
4950 if (user_msg == NULL) smtp_printf("250 OK\r\n");
4951 else smtp_user_msg(US"250", user_msg);
4954 signal(SIGCHLD, oldsignal);
4959 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4960 US"unexpected argument data");
4964 /* This currently happens only for NULLs, but could be extended. */
4967 done = synprot_error(L_smtp_syntax_error, 0, NULL, /* Just logs */
4968 US"NULL character(s) present (shown as '?')");
4969 smtp_printf("501 NULL characters are not allowed in SMTP commands\r\n");
4975 if (smtp_inend >= smtp_inbuffer + in_buffer_size)
4976 smtp_inend = smtp_inbuffer + in_buffer_size - 1;
4977 c = smtp_inend - smtp_inptr;
4978 if (c > 150) c = 150;
4980 incomplete_transaction_log(US"sync failure");
4981 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP protocol synchronization error "
4982 "(next input sent too soon: pipelining was%s advertised): "
4983 "rejected \"%s\" %s next input=\"%s\"",
4984 pipelining_advertised? "" : " not",
4985 smtp_cmd_buffer, host_and_ident(TRUE),
4986 string_printing(smtp_inptr));
4987 smtp_notquit_exit(US"synchronization-error", US"554",
4988 US"SMTP synchronization error");
4989 done = 1; /* Pretend eof - drops connection */
4993 case TOO_MANY_NONMAIL_CMD:
4994 s = smtp_cmd_buffer;
4995 while (*s != 0 && !isspace(*s)) s++;
4996 incomplete_transaction_log(US"too many non-mail commands");
4997 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
4998 "nonmail commands (last was \"%.*s\")", host_and_ident(FALSE),
4999 (int)(s - smtp_cmd_buffer), smtp_cmd_buffer);
5000 smtp_notquit_exit(US"bad-commands", US"554", US"Too many nonmail commands");
5001 done = 1; /* Pretend eof - drops connection */
5004 #ifdef EXPERIMENTAL_PROXY
5005 case PROXY_FAIL_IGNORE_CMD:
5006 smtp_printf("503 Command refused, required Proxy negotiation failed\r\n");
5011 if (unknown_command_count++ >= smtp_max_unknown_commands)
5013 log_write(L_smtp_syntax_error, LOG_MAIN,
5014 "SMTP syntax error in \"%s\" %s %s",
5015 string_printing(smtp_cmd_buffer), host_and_ident(TRUE),
5016 US"unrecognized command");
5017 incomplete_transaction_log(US"unrecognized command");
5018 smtp_notquit_exit(US"bad-commands", US"500",
5019 US"Too many unrecognized commands");
5021 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
5022 "unrecognized commands (last was \"%s\")", host_and_ident(FALSE),
5026 done = synprot_error(L_smtp_syntax_error, 500, NULL,
5027 US"unrecognized command");
5031 /* This label is used by goto's inside loops that want to break out to
5032 the end of the command-processing loop. */
5035 last_was_rej_mail = was_rej_mail; /* Remember some last commands for */
5036 last_was_rcpt = was_rcpt; /* protocol error handling */
5040 return done - 2; /* Convert yield values */
5045 /* End of smtp_in.c */