1 /*************************************************
2 * Exim - an Internet mail transport agent *
3 *************************************************/
5 /* Copyright (c) University of Cambridge 1995 - 2015 */
6 /* See the file NOTICE for conditions of use and distribution. */
8 /* Functions for handling an incoming SMTP call. */
15 /* Initialize for TCP wrappers if so configured. It appears that the macro
16 HAVE_IPV6 is used in some versions of the tcpd.h header, so we unset it before
17 including that header, and restore its value afterwards. */
19 #ifdef USE_TCP_WRAPPERS
22 #define EXIM_HAVE_IPV6
28 #define HAVE_IPV6 TRUE
31 int allow_severity = LOG_INFO;
32 int deny_severity = LOG_NOTICE;
33 uschar *tcp_wrappers_name;
37 /* Size of buffer for reading SMTP commands. We used to use 512, as defined
38 by RFC 821. However, RFC 1869 specifies that this must be increased for SMTP
39 commands that accept arguments, and this in particular applies to AUTH, where
40 the data can be quite long. More recently this value was 2048 in Exim;
41 however, RFC 4954 (circa 2007) recommends 12288 bytes to handle AUTH. Clients
42 such as Thunderbird will send an AUTH with an initial-response for GSSAPI.
43 The maximum size of a Kerberos ticket under Windows 2003 is 12000 bytes, and
44 we need room to handle large base64-encoded AUTHs for GSSAPI.
47 #define smtp_cmd_buffer_size 16384
49 /* Size of buffer for reading SMTP incoming packets */
51 #define in_buffer_size 8192
53 /* Structure for SMTP command list */
60 short int is_mail_cmd;
63 /* Codes for identifying commands. We order them so that those that come first
64 are those for which synchronization is always required. Checking this can help
68 /* These commands are required to be synchronized, i.e. to be the last in a
69 block of commands when pipelining. */
71 HELO_CMD, EHLO_CMD, DATA_CMD, /* These are listed in the pipelining */
72 VRFY_CMD, EXPN_CMD, NOOP_CMD, /* RFC as requiring synchronization */
73 ETRN_CMD, /* This by analogy with TURN from the RFC */
74 STARTTLS_CMD, /* Required by the STARTTLS RFC */
75 TLS_AUTH_CMD, /* auto-command at start of SSL */
77 /* This is a dummy to identify the non-sync commands when pipelining */
79 NON_SYNC_CMD_PIPELINING,
81 /* These commands need not be synchronized when pipelining */
83 MAIL_CMD, RCPT_CMD, RSET_CMD,
85 /* This is a dummy to identify the non-sync commands when not pipelining */
87 NON_SYNC_CMD_NON_PIPELINING,
89 /* I have been unable to find a statement about the use of pipelining
90 with AUTH, so to be on the safe side it is here, though I kind of feel
91 it should be up there with the synchronized commands. */
95 /* I'm not sure about these, but I don't think they matter. */
99 #ifdef EXPERIMENTAL_PROXY
100 PROXY_FAIL_IGNORE_CMD,
103 /* These are specials that don't correspond to actual commands */
105 EOF_CMD, OTHER_CMD, BADARG_CMD, BADCHAR_CMD, BADSYN_CMD,
106 TOO_MANY_NONMAIL_CMD };
109 /* This is a convenience macro for adding the identity of an SMTP command
110 to the circular buffer that holds a list of the last n received. */
113 smtp_connection_had[smtp_ch_index++] = n; \
114 if (smtp_ch_index >= SMTP_HBUFF_SIZE) smtp_ch_index = 0
117 /*************************************************
118 * Local static variables *
119 *************************************************/
121 static auth_instance *authenticated_by;
122 static BOOL auth_advertised;
124 static BOOL tls_advertised;
126 static BOOL dsn_advertised;
128 static BOOL helo_required = FALSE;
129 static BOOL helo_verify = FALSE;
130 static BOOL helo_seen;
131 static BOOL helo_accept_junk;
132 static BOOL count_nonmail;
133 static BOOL pipelining_advertised;
134 static BOOL rcpt_smtp_response_same;
135 static BOOL rcpt_in_progress;
136 static int nonmail_command_count;
137 static BOOL smtp_exit_function_called = 0;
138 #ifdef EXPERIMENTAL_INTERNATIONAL
139 static BOOL smtputf8_advertised;
141 static int synprot_error_count;
142 static int unknown_command_count;
143 static int sync_cmd_limit;
144 static int smtp_write_error = 0;
146 static uschar *rcpt_smtp_response;
147 static uschar *smtp_data_buffer;
148 static uschar *smtp_cmd_data;
150 /* We need to know the position of RSET, HELO, EHLO, AUTH, and STARTTLS. Their
151 final fields of all except AUTH are forced TRUE at the start of a new message
152 setup, to allow one of each between messages that is not counted as a nonmail
153 command. (In fact, only one of HELO/EHLO is not counted.) Also, we have to
154 allow a new EHLO after starting up TLS.
156 AUTH is "falsely" labelled as a mail command initially, so that it doesn't get
157 counted. However, the flag is changed when AUTH is received, so that multiple
158 failing AUTHs will eventually hit the limit. After a successful AUTH, another
159 AUTH is already forbidden. After a TLS session is started, AUTH's flag is again
160 forced TRUE, to allow for the re-authentication that can happen at that point.
162 QUIT is also "falsely" labelled as a mail command so that it doesn't up the
163 count of non-mail commands and possibly provoke an error.
165 tls_auth is a pseudo-command, never expected in input. It is activated
166 on TLS startup and looks for a tls authenticator. */
168 static smtp_cmd_list cmd_list[] = {
169 /* name len cmd has_arg is_mail_cmd */
171 { "rset", sizeof("rset")-1, RSET_CMD, FALSE, FALSE }, /* First */
172 { "helo", sizeof("helo")-1, HELO_CMD, TRUE, FALSE },
173 { "ehlo", sizeof("ehlo")-1, EHLO_CMD, TRUE, FALSE },
174 { "auth", sizeof("auth")-1, AUTH_CMD, TRUE, TRUE },
176 { "starttls", sizeof("starttls")-1, STARTTLS_CMD, FALSE, FALSE },
177 { "tls_auth", 0, TLS_AUTH_CMD, FALSE, TRUE },
180 /* If you change anything above here, also fix the definitions below. */
182 { "mail from:", sizeof("mail from:")-1, MAIL_CMD, TRUE, TRUE },
183 { "rcpt to:", sizeof("rcpt to:")-1, RCPT_CMD, TRUE, TRUE },
184 { "data", sizeof("data")-1, DATA_CMD, FALSE, TRUE },
185 { "quit", sizeof("quit")-1, QUIT_CMD, FALSE, TRUE },
186 { "noop", sizeof("noop")-1, NOOP_CMD, TRUE, FALSE },
187 { "etrn", sizeof("etrn")-1, ETRN_CMD, TRUE, FALSE },
188 { "vrfy", sizeof("vrfy")-1, VRFY_CMD, TRUE, FALSE },
189 { "expn", sizeof("expn")-1, EXPN_CMD, TRUE, FALSE },
190 { "help", sizeof("help")-1, HELP_CMD, TRUE, FALSE }
193 static smtp_cmd_list *cmd_list_end =
194 cmd_list + sizeof(cmd_list)/sizeof(smtp_cmd_list);
196 #define CMD_LIST_RSET 0
197 #define CMD_LIST_HELO 1
198 #define CMD_LIST_EHLO 2
199 #define CMD_LIST_AUTH 3
200 #define CMD_LIST_STARTTLS 4
201 #define CMD_LIST_TLS_AUTH 5
203 /* This list of names is used for performing the smtp_no_mail logging action.
204 It must be kept in step with the SCH_xxx enumerations. */
206 static uschar *smtp_names[] =
208 US"NONE", US"AUTH", US"DATA", US"EHLO", US"ETRN", US"EXPN", US"HELO",
209 US"HELP", US"MAIL", US"NOOP", US"QUIT", US"RCPT", US"RSET", US"STARTTLS",
212 static uschar *protocols_local[] = {
213 US"local-smtp", /* HELO */
214 US"local-smtps", /* The rare case EHLO->STARTTLS->HELO */
215 US"local-esmtp", /* EHLO */
216 US"local-esmtps", /* EHLO->STARTTLS->EHLO */
217 US"local-esmtpa", /* EHLO->AUTH */
218 US"local-esmtpsa" /* EHLO->STARTTLS->EHLO->AUTH */
220 static uschar *protocols[] = {
222 US"smtps", /* The rare case EHLO->STARTTLS->HELO */
223 US"esmtp", /* EHLO */
224 US"esmtps", /* EHLO->STARTTLS->EHLO */
225 US"esmtpa", /* EHLO->AUTH */
226 US"esmtpsa" /* EHLO->STARTTLS->EHLO->AUTH */
231 #define pcrpted 1 /* added to pextend or pnormal */
232 #define pauthed 2 /* added to pextend */
234 /* Sanity check and validate optional args to MAIL FROM: envelope */
237 ENV_MAIL_OPT_SIZE, ENV_MAIL_OPT_BODY, ENV_MAIL_OPT_AUTH,
241 ENV_MAIL_OPT_RET, ENV_MAIL_OPT_ENVID,
242 #ifdef EXPERIMENTAL_INTERNATIONAL
247 uschar * name; /* option requested during MAIL cmd */
248 int value; /* enum type */
249 BOOL need_value; /* TRUE requires value (name=value pair format)
250 FALSE is a singleton */
252 static env_mail_type_t env_mail_type_list[] = {
253 { US"SIZE", ENV_MAIL_OPT_SIZE, TRUE },
254 { US"BODY", ENV_MAIL_OPT_BODY, TRUE },
255 { US"AUTH", ENV_MAIL_OPT_AUTH, TRUE },
257 { US"PRDR", ENV_MAIL_OPT_PRDR, FALSE },
259 { US"RET", ENV_MAIL_OPT_RET, TRUE },
260 { US"ENVID", ENV_MAIL_OPT_ENVID, TRUE },
261 #ifdef EXPERIMENTAL_INTERNATIONAL
262 { US"SMTPUTF8",ENV_MAIL_OPT_UTF8, FALSE }, /* rfc6531 */
264 /* keep this the last entry */
265 { US"NULL", ENV_MAIL_OPT_NULL, FALSE },
268 /* When reading SMTP from a remote host, we have to use our own versions of the
269 C input-reading functions, in order to be able to flush the SMTP output only
270 when about to read more data from the socket. This is the only way to get
271 optimal performance when the client is using pipelining. Flushing for every
272 command causes a separate packet and reply packet each time; saving all the
273 responses up (when pipelining) combines them into one packet and one response.
275 For simplicity, these functions are used for *all* SMTP input, not only when
276 receiving over a socket. However, after setting up a secure socket (SSL), input
277 is read via the OpenSSL library, and another set of functions is used instead
280 These functions are set in the receive_getc etc. variables and called with the
281 same interface as the C functions. However, since there can only ever be
282 one incoming SMTP call, we just use a single buffer and flags. There is no need
283 to implement a complicated private FILE-like structure.*/
285 static uschar *smtp_inbuffer;
286 static uschar *smtp_inptr;
287 static uschar *smtp_inend;
288 static int smtp_had_eof;
289 static int smtp_had_error;
292 /*************************************************
293 * SMTP version of getc() *
294 *************************************************/
296 /* This gets the next byte from the SMTP input buffer. If the buffer is empty,
297 it flushes the output, and refills the buffer, with a timeout. The signal
298 handler is set appropriately by the calling function. This function is not used
299 after a connection has negotated itself into an TLS/SSL state.
302 Returns: the next character or EOF
308 if (smtp_inptr >= smtp_inend)
312 if (smtp_receive_timeout > 0) alarm(smtp_receive_timeout);
313 rc = read(fileno(smtp_in), smtp_inbuffer, in_buffer_size);
318 /* Must put the error text in fixed store, because this might be during
319 header reading, where it releases unused store above the header. */
322 smtp_had_error = save_errno;
323 smtp_read_error = string_copy_malloc(
324 string_sprintf(" (error: %s)", strerror(save_errno)));
326 else smtp_had_eof = 1;
330 dkim_exim_verify_feed(smtp_inbuffer, rc);
332 smtp_inend = smtp_inbuffer + rc;
333 smtp_inptr = smtp_inbuffer;
335 return *smtp_inptr++;
340 /*************************************************
341 * SMTP version of ungetc() *
342 *************************************************/
344 /* Puts a character back in the input buffer. Only ever
350 Returns: the character
356 *(--smtp_inptr) = ch;
363 /*************************************************
364 * SMTP version of feof() *
365 *************************************************/
367 /* Tests for a previous EOF
370 Returns: non-zero if the eof flag is set
382 /*************************************************
383 * SMTP version of ferror() *
384 *************************************************/
386 /* Tests for a previous read error, and returns with errno
387 restored to what it was when the error was detected.
390 Returns: non-zero if the error flag is set
396 errno = smtp_had_error;
397 return smtp_had_error;
402 /*************************************************
403 * Test for characters in the SMTP buffer *
404 *************************************************/
406 /* Used at the end of a message
415 return smtp_inptr < smtp_inend;
420 /*************************************************
421 * Write formatted string to SMTP channel *
422 *************************************************/
424 /* This is a separate function so that we don't have to repeat everything for
425 TLS support or debugging. It is global so that the daemon and the
426 authentication functions can use it. It does not return any error indication,
427 because major problems such as dropped connections won't show up till an output
428 flush for non-TLS connections. The smtp_fflush() function is available for
429 checking that: for convenience, TLS output errors are remembered here so that
430 they are also picked up later by smtp_fflush().
434 ... optional arguments
440 smtp_printf(const char *format, ...)
444 va_start(ap, format);
445 smtp_vprintf(format, ap);
449 /* This is split off so that verify.c:respond_printf() can, in effect, call
450 smtp_printf(), bearing in mind that in C a vararg function can't directly
451 call another vararg function, only a function which accepts a va_list. */
454 smtp_vprintf(const char *format, va_list ap)
458 yield = string_vformat(big_buffer, big_buffer_size, format, ap);
462 void *reset_point = store_get(0);
463 uschar *msg_copy, *cr, *end;
464 msg_copy = string_copy(big_buffer);
465 end = msg_copy + Ustrlen(msg_copy);
466 while ((cr = Ustrchr(msg_copy, '\r')) != NULL) /* lose CRs */
467 memmove(cr, cr + 1, (end--) - cr);
468 debug_printf("SMTP>> %s", msg_copy);
469 store_reset(reset_point);
474 log_write(0, LOG_MAIN|LOG_PANIC, "string too large in smtp_printf()");
475 smtp_closedown(US"Unexpected error");
476 exim_exit(EXIT_FAILURE);
479 /* If this is the first output for a (non-batch) RCPT command, see if all RCPTs
480 have had the same. Note: this code is also present in smtp_respond(). It would
481 be tidier to have it only in one place, but when it was added, it was easier to
482 do it that way, so as not to have to mess with the code for the RCPT command,
483 which sometimes uses smtp_printf() and sometimes smtp_respond(). */
485 if (rcpt_in_progress)
487 if (rcpt_smtp_response == NULL)
488 rcpt_smtp_response = string_copy(big_buffer);
489 else if (rcpt_smtp_response_same &&
490 Ustrcmp(rcpt_smtp_response, big_buffer) != 0)
491 rcpt_smtp_response_same = FALSE;
492 rcpt_in_progress = FALSE;
495 /* Now write the string */
498 if (tls_in.active >= 0)
500 if (tls_write(TRUE, big_buffer, Ustrlen(big_buffer)) < 0)
501 smtp_write_error = -1;
506 if (fprintf(smtp_out, "%s", big_buffer) < 0) smtp_write_error = -1;
511 /*************************************************
512 * Flush SMTP out and check for error *
513 *************************************************/
515 /* This function isn't currently used within Exim (it detects errors when it
516 tries to read the next SMTP input), but is available for use in local_scan().
517 For non-TLS connections, it flushes the output and checks for errors. For
518 TLS-connections, it checks for a previously-detected TLS write error.
521 Returns: 0 for no error; -1 after an error
527 if (tls_in.active < 0 && fflush(smtp_out) != 0) smtp_write_error = -1;
528 return smtp_write_error;
533 /*************************************************
534 * SMTP command read timeout *
535 *************************************************/
537 /* Signal handler for timing out incoming SMTP commands. This attempts to
540 Argument: signal number (SIGALRM)
545 command_timeout_handler(int sig)
547 sig = sig; /* Keep picky compilers happy */
548 log_write(L_lost_incoming_connection,
549 LOG_MAIN, "SMTP command timeout on%s connection from %s",
550 (tls_in.active >= 0)? " TLS" : "",
551 host_and_ident(FALSE));
552 if (smtp_batched_input)
553 moan_smtp_batch(NULL, "421 SMTP command timeout"); /* Does not return */
554 smtp_notquit_exit(US"command-timeout", US"421",
555 US"%s: SMTP command timeout - closing connection", smtp_active_hostname);
556 exim_exit(EXIT_FAILURE);
561 /*************************************************
563 *************************************************/
565 /* Signal handler for handling SIGTERM. Again, try to finish tidily.
567 Argument: signal number (SIGTERM)
572 command_sigterm_handler(int sig)
574 sig = sig; /* Keep picky compilers happy */
575 log_write(0, LOG_MAIN, "%s closed after SIGTERM", smtp_get_connection_info());
576 if (smtp_batched_input)
577 moan_smtp_batch(NULL, "421 SIGTERM received"); /* Does not return */
578 smtp_notquit_exit(US"signal-exit", US"421",
579 US"%s: Service not available - closing connection", smtp_active_hostname);
580 exim_exit(EXIT_FAILURE);
586 #ifdef EXPERIMENTAL_PROXY
587 /*************************************************
588 * Restore socket timeout to previous value *
589 *************************************************/
590 /* If the previous value was successfully retrieved, restore
591 it before returning control to the non-proxy routines
593 Arguments: fd - File descriptor for input
594 get_ok - Successfully retrieved previous values
595 tvtmp - Time struct with previous values
596 vslen - Length of time struct
600 restore_socket_timeout(int fd, int get_ok, struct timeval tvtmp, socklen_t vslen)
603 setsockopt(fd, SOL_SOCKET, SO_RCVTIMEO, (char *)&tvtmp, vslen);
606 /*************************************************
607 * Check if host is required proxy host *
608 *************************************************/
609 /* The function determines if inbound host will be a regular smtp host
610 or if it is configured that it must use Proxy Protocol.
617 check_proxy_protocol_host()
620 /* Cannot configure local connection as a proxy inbound */
621 if (sender_host_address == NULL) return proxy_session;
623 rc = verify_check_this_host(&proxy_required_hosts, NULL, NULL,
624 sender_host_address, NULL);
628 debug_printf("Detected proxy protocol configured host\n");
629 proxy_session = TRUE;
631 return proxy_session;
635 /*************************************************
636 * Setup host for proxy protocol *
637 *************************************************/
638 /* The function configures the connection based on a header from the
639 inbound host to use Proxy Protocol. The specification is very exact
640 so exit with an error if do not find the exact required pieces. This
641 includes an incorrect number of spaces separating args.
648 setup_proxy_protocol_host()
660 struct { /* TCP/UDP over IPv4, len = 12 */
666 struct { /* TCP/UDP over IPv6, len = 36 */
667 uint8_t src_addr[16];
668 uint8_t dst_addr[16];
672 struct { /* AF_UNIX sockets, len = 216 */
673 uschar src_addr[108];
674 uschar dst_addr[108];
680 /* Temp variables used in PPv2 address:port parsing */
682 char tmpip[INET_ADDRSTRLEN];
683 struct sockaddr_in tmpaddr;
684 char tmpip6[INET6_ADDRSTRLEN];
685 struct sockaddr_in6 tmpaddr6;
689 const char v2sig[12] = "\x0D\x0A\x0D\x0A\x00\x0D\x0A\x51\x55\x49\x54\x0A";
690 uschar *iptype; /* To display debug info */
693 struct timeval tvtmp;
695 vslen = sizeof(struct timeval);
697 fd = fileno(smtp_in);
699 /* Save current socket timeout values */
700 get_ok = getsockopt(fd, SOL_SOCKET, SO_RCVTIMEO, (char *)&tvtmp,
703 /* Proxy Protocol host must send header within a short time
704 (default 3 seconds) or it's considered invalid */
705 tv.tv_sec = PROXY_NEGOTIATION_TIMEOUT_SEC;
706 tv.tv_usec = PROXY_NEGOTIATION_TIMEOUT_USEC;
707 setsockopt(fd, SOL_SOCKET, SO_RCVTIMEO, (char *)&tv,
708 sizeof(struct timeval));
712 /* The inbound host was declared to be a Proxy Protocol host, so
713 don't do a PEEK into the data, actually slurp it up. */
714 ret = recv(fd, &hdr, sizeof(hdr), 0);
716 while (ret == -1 && errno == EINTR);
720 restore_socket_timeout(fd, get_ok, tvtmp, vslen);
721 return (errno == EAGAIN) ? 0 : ERRNO_PROXYFAIL;
725 memcmp(&hdr.v2, v2sig, 12) == 0)
729 /* May 2014: haproxy combined the version and command into one byte to
730 allow two full bytes for the length field in order to proxy SSL
731 connections. SSL Proxy is not supported in this version of Exim, but
732 must still seperate values here. */
733 ver = (hdr.v2.ver_cmd & 0xf0) >> 4;
734 cmd = (hdr.v2.ver_cmd & 0x0f);
738 DEBUG(D_receive) debug_printf("Invalid Proxy Protocol version: %d\n", ver);
741 DEBUG(D_receive) debug_printf("Detected PROXYv2 header\n");
742 /* The v2 header will always be 16 bytes per the spec. */
743 size = 16 + hdr.v2.len;
746 DEBUG(D_receive) debug_printf("Truncated or too large PROXYv2 header (%d/%d)\n",
752 case 0x01: /* PROXY command */
755 case 0x11: /* TCPv4 address type */
757 tmpaddr.sin_addr.s_addr = hdr.v2.addr.ip4.src_addr;
758 inet_ntop(AF_INET, &(tmpaddr.sin_addr), (char *)&tmpip, sizeof(tmpip));
759 if (!string_is_ip_address(US tmpip,NULL))
761 DEBUG(D_receive) debug_printf("Invalid %s source IP\n", iptype);
762 return ERRNO_PROXYFAIL;
764 proxy_host_address = sender_host_address;
765 sender_host_address = string_copy(US tmpip);
766 tmpport = ntohs(hdr.v2.addr.ip4.src_port);
767 proxy_host_port = sender_host_port;
768 sender_host_port = tmpport;
769 /* Save dest ip/port */
770 tmpaddr.sin_addr.s_addr = hdr.v2.addr.ip4.dst_addr;
771 inet_ntop(AF_INET, &(tmpaddr.sin_addr), (char *)&tmpip, sizeof(tmpip));
772 if (!string_is_ip_address(US tmpip,NULL))
774 DEBUG(D_receive) debug_printf("Invalid %s dest port\n", iptype);
775 return ERRNO_PROXYFAIL;
777 proxy_target_address = string_copy(US tmpip);
778 tmpport = ntohs(hdr.v2.addr.ip4.dst_port);
779 proxy_target_port = tmpport;
781 case 0x21: /* TCPv6 address type */
783 memmove(tmpaddr6.sin6_addr.s6_addr, hdr.v2.addr.ip6.src_addr, 16);
784 inet_ntop(AF_INET6, &(tmpaddr6.sin6_addr), (char *)&tmpip6, sizeof(tmpip6));
785 if (!string_is_ip_address(US tmpip6,NULL))
787 DEBUG(D_receive) debug_printf("Invalid %s source IP\n", iptype);
788 return ERRNO_PROXYFAIL;
790 proxy_host_address = sender_host_address;
791 sender_host_address = string_copy(US tmpip6);
792 tmpport = ntohs(hdr.v2.addr.ip6.src_port);
793 proxy_host_port = sender_host_port;
794 sender_host_port = tmpport;
795 /* Save dest ip/port */
796 memmove(tmpaddr6.sin6_addr.s6_addr, hdr.v2.addr.ip6.dst_addr, 16);
797 inet_ntop(AF_INET6, &(tmpaddr6.sin6_addr), (char *)&tmpip6, sizeof(tmpip6));
798 if (!string_is_ip_address(US tmpip6,NULL))
800 DEBUG(D_receive) debug_printf("Invalid %s dest port\n", iptype);
801 return ERRNO_PROXYFAIL;
803 proxy_target_address = string_copy(US tmpip6);
804 tmpport = ntohs(hdr.v2.addr.ip6.dst_port);
805 proxy_target_port = tmpport;
809 debug_printf("Unsupported PROXYv2 connection type: 0x%02x\n",
813 /* Unsupported protocol, keep local connection address */
815 case 0x00: /* LOCAL command */
816 /* Keep local connection address for LOCAL */
820 debug_printf("Unsupported PROXYv2 command: 0x%x\n", cmd);
825 memcmp(hdr.v1.line, "PROXY", 5) == 0)
827 uschar *p = string_copy(hdr.v1.line);
828 uschar *end = memchr(p, '\r', ret - 1);
829 uschar *sp; /* Utility variables follow */
833 if (!end || end[1] != '\n')
835 DEBUG(D_receive) debug_printf("Partial or invalid PROXY header\n");
838 *end = '\0'; /* Terminate the string */
839 size = end + 2 - hdr.v1.line; /* Skip header + CRLF */
840 DEBUG(D_receive) debug_printf("Detected PROXYv1 header\n");
841 /* Step through the string looking for the required fields. Ensure
842 strict adherance to required formatting, exit for any error. */
844 if (!isspace(*(p++)))
846 DEBUG(D_receive) debug_printf("Missing space after PROXY command\n");
849 if (!Ustrncmp(p, CCS"TCP4", 4))
851 else if (!Ustrncmp(p,CCS"TCP6", 4))
853 else if (!Ustrncmp(p,CCS"UNKNOWN", 7))
855 iptype = US"Unknown";
860 DEBUG(D_receive) debug_printf("Invalid TCP type\n");
864 p += Ustrlen(iptype);
865 if (!isspace(*(p++)))
867 DEBUG(D_receive) debug_printf("Missing space after TCP4/6 command\n");
870 /* Find the end of the arg */
871 if ((sp = Ustrchr(p, ' ')) == NULL)
874 debug_printf("Did not find proxied src %s\n", iptype);
878 if(!string_is_ip_address(p,NULL))
881 debug_printf("Proxied src arg is not an %s address\n", iptype);
884 proxy_host_address = sender_host_address;
885 sender_host_address = p;
887 if ((sp = Ustrchr(p, ' ')) == NULL)
890 debug_printf("Did not find proxy dest %s\n", iptype);
894 if(!string_is_ip_address(p,NULL))
897 debug_printf("Proxy dest arg is not an %s address\n", iptype);
900 proxy_target_address = p;
902 if ((sp = Ustrchr(p, ' ')) == NULL)
904 DEBUG(D_receive) debug_printf("Did not find proxied src port\n");
908 tmp_port = strtol(CCS p,&endc,10);
909 if (*endc || tmp_port == 0)
912 debug_printf("Proxied src port '%s' not an integer\n", p);
915 proxy_host_port = sender_host_port;
916 sender_host_port = tmp_port;
918 if ((sp = Ustrchr(p, '\0')) == NULL)
920 DEBUG(D_receive) debug_printf("Did not find proxy dest port\n");
923 tmp_port = strtol(CCS p,&endc,10);
924 if (*endc || tmp_port == 0)
927 debug_printf("Proxy dest port '%s' not an integer\n", p);
930 proxy_target_port = tmp_port;
931 /* Already checked for /r /n above. Good V1 header received. */
937 DEBUG(D_receive) debug_printf("Invalid proxy protocol version negotiation\n");
942 restore_socket_timeout(fd, get_ok, tvtmp, vslen);
943 /* Don't flush any potential buffer contents. Any input should cause a
944 synchronization failure */
948 restore_socket_timeout(fd, get_ok, tvtmp, vslen);
950 debug_printf("Valid %s sender from Proxy Protocol header\n", iptype);
951 return proxy_session;
955 /*************************************************
956 * Read one command line *
957 *************************************************/
959 /* Strictly, SMTP commands coming over the net are supposed to end with CRLF.
960 There are sites that don't do this, and in any case internal SMTP probably
961 should check only for LF. Consequently, we check here for LF only. The line
962 ends up with [CR]LF removed from its end. If we get an overlong line, treat as
963 an unknown command. The command is read into the global smtp_cmd_buffer so that
964 it is available via $smtp_command.
966 The character reading routine sets up a timeout for each block actually read
967 from the input (which may contain more than one command). We set up a special
968 signal handler that closes down the session on a timeout. Control does not
972 check_sync if TRUE, check synchronization rules if global option is TRUE
974 Returns: a code identifying the command (enumerated above)
978 smtp_read_command(BOOL check_sync)
983 BOOL hadnull = FALSE;
985 os_non_restarting_signal(SIGALRM, command_timeout_handler);
987 while ((c = (receive_getc)()) != '\n' && c != EOF)
989 if (ptr >= smtp_cmd_buffer_size)
991 os_non_restarting_signal(SIGALRM, sigalrm_handler);
999 smtp_cmd_buffer[ptr++] = c;
1002 receive_linecount++; /* For BSMTP errors */
1003 os_non_restarting_signal(SIGALRM, sigalrm_handler);
1005 /* If hit end of file, return pseudo EOF command. Whether we have a
1006 part-line already read doesn't matter, since this is an error state. */
1008 if (c == EOF) return EOF_CMD;
1010 /* Remove any CR and white space at the end of the line, and terminate the
1013 while (ptr > 0 && isspace(smtp_cmd_buffer[ptr-1])) ptr--;
1014 smtp_cmd_buffer[ptr] = 0;
1016 DEBUG(D_receive) debug_printf("SMTP<< %s\n", smtp_cmd_buffer);
1018 /* NULLs are not allowed in SMTP commands */
1020 if (hadnull) return BADCHAR_CMD;
1022 /* Scan command list and return identity, having set the data pointer
1023 to the start of the actual data characters. Check for SMTP synchronization
1026 for (p = cmd_list; p < cmd_list_end; p++)
1028 #ifdef EXPERIMENTAL_PROXY
1029 /* Only allow QUIT command if Proxy Protocol parsing failed */
1030 if (proxy_session && proxy_session_failed)
1032 if (p->cmd != QUIT_CMD)
1037 && strncmpic(smtp_cmd_buffer, US p->name, p->len) == 0
1038 && ( smtp_cmd_buffer[p->len-1] == ':' /* "mail from:" or "rcpt to:" */
1039 || smtp_cmd_buffer[p->len] == 0
1040 || smtp_cmd_buffer[p->len] == ' '
1043 if (smtp_inptr < smtp_inend && /* Outstanding input */
1044 p->cmd < sync_cmd_limit && /* Command should sync */
1045 check_sync && /* Local flag set */
1046 smtp_enforce_sync && /* Global flag set */
1047 sender_host_address != NULL && /* Not local input */
1048 !sender_host_notsocket) /* Really is a socket */
1051 /* The variables $smtp_command and $smtp_command_argument point into the
1052 unmodified input buffer. A copy of the latter is taken for actual
1053 processing, so that it can be chopped up into separate parts if necessary,
1054 for example, when processing a MAIL command options such as SIZE that can
1055 follow the sender address. */
1057 smtp_cmd_argument = smtp_cmd_buffer + p->len;
1058 while (isspace(*smtp_cmd_argument)) smtp_cmd_argument++;
1059 Ustrcpy(smtp_data_buffer, smtp_cmd_argument);
1060 smtp_cmd_data = smtp_data_buffer;
1062 /* Count non-mail commands from those hosts that are controlled in this
1063 way. The default is all hosts. We don't waste effort checking the list
1064 until we get a non-mail command, but then cache the result to save checking
1065 again. If there's a DEFER while checking the host, assume it's in the list.
1067 Note that one instance of RSET, EHLO/HELO, and STARTTLS is allowed at the
1068 start of each incoming message by fiddling with the value in the table. */
1070 if (!p->is_mail_cmd)
1072 if (count_nonmail == TRUE_UNSET) count_nonmail =
1073 verify_check_host(&smtp_accept_max_nonmail_hosts) != FAIL;
1074 if (count_nonmail && ++nonmail_command_count > smtp_accept_max_nonmail)
1075 return TOO_MANY_NONMAIL_CMD;
1078 /* If there is data for a command that does not expect it, generate the
1081 return (p->has_arg || *smtp_cmd_data == 0)? p->cmd : BADARG_CMD;
1085 #ifdef EXPERIMENTAL_PROXY
1086 /* Only allow QUIT command if Proxy Protocol parsing failed */
1087 if (proxy_session && proxy_session_failed)
1088 return PROXY_FAIL_IGNORE_CMD;
1091 /* Enforce synchronization for unknown commands */
1093 if (smtp_inptr < smtp_inend && /* Outstanding input */
1094 check_sync && /* Local flag set */
1095 smtp_enforce_sync && /* Global flag set */
1096 sender_host_address != NULL && /* Not local input */
1097 !sender_host_notsocket) /* Really is a socket */
1105 /*************************************************
1106 * Recheck synchronization *
1107 *************************************************/
1109 /* Synchronization checks can never be perfect because a packet may be on its
1110 way but not arrived when the check is done. Such checks can in any case only be
1111 done when TLS is not in use. Normally, the checks happen when commands are
1112 read: Exim ensures that there is no more input in the input buffer. In normal
1113 cases, the response to the command will be fast, and there is no further check.
1115 However, for some commands an ACL is run, and that can include delays. In those
1116 cases, it is useful to do another check on the input just before sending the
1117 response. This also applies at the start of a connection. This function does
1118 that check by means of the select() function, as long as the facility is not
1119 disabled or inappropriate. A failure of select() is ignored.
1121 When there is unwanted input, we read it so that it appears in the log of the
1125 Returns: TRUE if all is well; FALSE if there is input pending
1133 struct timeval tzero;
1135 if (!smtp_enforce_sync || sender_host_address == NULL ||
1136 sender_host_notsocket || tls_in.active >= 0)
1139 fd = fileno(smtp_in);
1144 rc = select(fd + 1, (SELECT_ARG2_TYPE *)&fds, NULL, NULL, &tzero);
1146 if (rc <= 0) return TRUE; /* Not ready to read */
1148 if (rc < 0) return TRUE; /* End of file or error */
1151 rc = smtp_inend - smtp_inptr;
1152 if (rc > 150) rc = 150;
1159 /*************************************************
1160 * Forced closedown of call *
1161 *************************************************/
1163 /* This function is called from log.c when Exim is dying because of a serious
1164 disaster, and also from some other places. If an incoming non-batched SMTP
1165 channel is open, it swallows the rest of the incoming message if in the DATA
1166 phase, sends the reply string, and gives an error to all subsequent commands
1167 except QUIT. The existence of an SMTP call is detected by the non-NULLness of
1171 message SMTP reply string to send, excluding the code
1177 smtp_closedown(uschar *message)
1179 if (smtp_in == NULL || smtp_batched_input) return;
1180 receive_swallow_smtp();
1181 smtp_printf("421 %s\r\n", message);
1185 switch(smtp_read_command(FALSE))
1191 smtp_printf("221 %s closing connection\r\n", smtp_active_hostname);
1196 smtp_printf("250 Reset OK\r\n");
1200 smtp_printf("421 %s\r\n", message);
1209 /*************************************************
1210 * Set up connection info for logging *
1211 *************************************************/
1213 /* This function is called when logging information about an SMTP connection.
1214 It sets up appropriate source information, depending on the type of connection.
1215 If sender_fullhost is NULL, we are at a very early stage of the connection;
1216 just use the IP address.
1219 Returns: a string describing the connection
1223 smtp_get_connection_info(void)
1225 uschar *hostname = (sender_fullhost == NULL)?
1226 sender_host_address : sender_fullhost;
1229 return string_sprintf("SMTP connection from %s", hostname);
1231 if (sender_host_unknown || sender_host_notsocket)
1232 return string_sprintf("SMTP connection from %s", sender_ident);
1235 return string_sprintf("SMTP connection from %s (via inetd)", hostname);
1237 if ((log_extra_selector & LX_incoming_interface) != 0 &&
1238 interface_address != NULL)
1239 return string_sprintf("SMTP connection from %s I=[%s]:%d", hostname,
1240 interface_address, interface_port);
1242 return string_sprintf("SMTP connection from %s", hostname);
1248 /* Append TLS-related information to a log line
1251 s String under construction: allocated string to extend, or NULL
1252 sizep Pointer to current allocation size (update on return), or NULL
1253 ptrp Pointer to index for new entries in string (update on return), or NULL
1255 Returns: Allocated string or NULL
1258 s_tlslog(uschar * s, int * sizep, int * ptrp)
1260 int size = sizep ? *sizep : 0;
1261 int ptr = ptrp ? *ptrp : 0;
1263 if ((log_extra_selector & LX_tls_cipher) != 0 && tls_in.cipher != NULL)
1264 s = string_append(s, &size, &ptr, 2, US" X=", tls_in.cipher);
1265 if ((log_extra_selector & LX_tls_certificate_verified) != 0 &&
1266 tls_in.cipher != NULL)
1267 s = string_append(s, &size, &ptr, 2, US" CV=",
1268 tls_in.certificate_verified? "yes":"no");
1269 if ((log_extra_selector & LX_tls_peerdn) != 0 && tls_in.peerdn != NULL)
1270 s = string_append(s, &size, &ptr, 3, US" DN=\"",
1271 string_printing(tls_in.peerdn), US"\"");
1272 if ((log_extra_selector & LX_tls_sni) != 0 && tls_in.sni != NULL)
1273 s = string_append(s, &size, &ptr, 3, US" SNI=\"",
1274 string_printing(tls_in.sni), US"\"");
1279 if (sizep) *sizep = size;
1280 if (ptrp) *ptrp = ptr;
1286 /*************************************************
1287 * Log lack of MAIL if so configured *
1288 *************************************************/
1290 /* This function is called when an SMTP session ends. If the log selector
1291 smtp_no_mail is set, write a log line giving some details of what has happened
1292 in the SMTP session.
1299 smtp_log_no_mail(void)
1304 if (smtp_mailcmd_count > 0 || (log_extra_selector & LX_smtp_no_mail) == 0)
1310 if (sender_host_authenticated != NULL)
1312 s = string_append(s, &size, &ptr, 2, US" A=", sender_host_authenticated);
1313 if (authenticated_id != NULL)
1314 s = string_append(s, &size, &ptr, 2, US":", authenticated_id);
1318 s = s_tlslog(s, &size, &ptr);
1321 sep = (smtp_connection_had[SMTP_HBUFF_SIZE-1] != SCH_NONE)?
1322 US" C=..." : US" C=";
1323 for (i = smtp_ch_index; i < SMTP_HBUFF_SIZE; i++)
1325 if (smtp_connection_had[i] != SCH_NONE)
1327 s = string_append(s, &size, &ptr, 2, sep,
1328 smtp_names[smtp_connection_had[i]]);
1333 for (i = 0; i < smtp_ch_index; i++)
1335 s = string_append(s, &size, &ptr, 2, sep, smtp_names[smtp_connection_had[i]]);
1339 if (s != NULL) s[ptr] = 0; else s = US"";
1340 log_write(0, LOG_MAIN, "no MAIL in SMTP connection from %s D=%s%s",
1341 host_and_ident(FALSE),
1342 readconf_printtime( (int) ((long)time(NULL) - (long)smtp_connection_start)),
1348 /*************************************************
1349 * Check HELO line and set sender_helo_name *
1350 *************************************************/
1352 /* Check the format of a HELO line. The data for HELO/EHLO is supposed to be
1353 the domain name of the sending host, or an ip literal in square brackets. The
1354 arrgument is placed in sender_helo_name, which is in malloc store, because it
1355 must persist over multiple incoming messages. If helo_accept_junk is set, this
1356 host is permitted to send any old junk (needed for some broken hosts).
1357 Otherwise, helo_allow_chars can be used for rogue characters in general
1358 (typically people want to let in underscores).
1361 s the data portion of the line (already past any white space)
1363 Returns: TRUE or FALSE
1367 check_helo(uschar *s)
1370 uschar *end = s + Ustrlen(s);
1371 BOOL yield = helo_accept_junk;
1373 /* Discard any previous helo name */
1375 if (sender_helo_name != NULL)
1377 store_free(sender_helo_name);
1378 sender_helo_name = NULL;
1381 /* Skip tests if junk is permitted. */
1385 /* Allow the new standard form for IPv6 address literals, namely,
1386 [IPv6:....], and because someone is bound to use it, allow an equivalent
1387 IPv4 form. Allow plain addresses as well. */
1394 if (strncmpic(s, US"[IPv6:", 6) == 0)
1395 yield = (string_is_ip_address(s+6, NULL) == 6);
1396 else if (strncmpic(s, US"[IPv4:", 6) == 0)
1397 yield = (string_is_ip_address(s+6, NULL) == 4);
1399 yield = (string_is_ip_address(s+1, NULL) != 0);
1404 /* Non-literals must be alpha, dot, hyphen, plus any non-valid chars
1405 that have been configured (usually underscore - sigh). */
1412 if (!isalnum(*s) && *s != '.' && *s != '-' &&
1413 Ustrchr(helo_allow_chars, *s) == NULL)
1423 /* Save argument if OK */
1425 if (yield) sender_helo_name = string_copy_malloc(start);
1433 /*************************************************
1434 * Extract SMTP command option *
1435 *************************************************/
1437 /* This function picks the next option setting off the end of smtp_cmd_data. It
1438 is called for MAIL FROM and RCPT TO commands, to pick off the optional ESMTP
1439 things that can appear there.
1442 name point this at the name
1443 value point this at the data string
1445 Returns: TRUE if found an option
1449 extract_option(uschar **name, uschar **value)
1452 uschar *v = smtp_cmd_data + Ustrlen(smtp_cmd_data) - 1;
1453 while (isspace(*v)) v--;
1455 while (v > smtp_cmd_data && *v != '=' && !isspace(*v)) v--;
1460 while(isalpha(n[-1])) n--;
1461 /* RFC says SP, but TAB seen in wild and other major MTAs accept it */
1462 if (!isspace(n[-1])) return FALSE;
1468 if (v == smtp_cmd_data) return FALSE;
1480 /*************************************************
1481 * Reset for new message *
1482 *************************************************/
1484 /* This function is called whenever the SMTP session is reset from
1485 within either of the setup functions.
1487 Argument: the stacking pool storage reset point
1492 smtp_reset(void *reset_point)
1494 store_reset(reset_point);
1495 recipients_list = NULL;
1496 rcpt_count = rcpt_defer_count = rcpt_fail_count =
1497 raw_recipients_count = recipients_count = recipients_list_max = 0;
1498 cancel_cutthrough_connection("smtp reset");
1499 message_linecount = 0;
1501 acl_added_headers = NULL;
1502 acl_removed_headers = NULL;
1503 queue_only_policy = FALSE;
1504 rcpt_smtp_response = NULL;
1505 rcpt_smtp_response_same = TRUE;
1506 rcpt_in_progress = FALSE;
1507 deliver_freeze = FALSE; /* Can be set by ACL */
1508 freeze_tell = freeze_tell_config; /* Can be set by ACL */
1509 fake_response = OK; /* Can be set by ACL */
1510 #ifdef WITH_CONTENT_SCAN
1511 no_mbox_unspool = FALSE; /* Can be set by ACL */
1513 submission_mode = FALSE; /* Can be set by ACL */
1514 suppress_local_fixups = suppress_local_fixups_default; /* Can be set by ACL */
1515 active_local_from_check = local_from_check; /* Can be set by ACL */
1516 active_local_sender_retain = local_sender_retain; /* Can be set by ACL */
1517 sender_address = NULL;
1518 submission_name = NULL; /* Can be set by ACL */
1519 raw_sender = NULL; /* After SMTP rewrite, before qualifying */
1520 sender_address_unrewritten = NULL; /* Set only after verify rewrite */
1521 sender_verified_list = NULL; /* No senders verified */
1522 memset(sender_address_cache, 0, sizeof(sender_address_cache));
1523 memset(sender_domain_cache, 0, sizeof(sender_domain_cache));
1525 #ifndef DISABLE_PRDR
1526 prdr_requested = FALSE;
1529 /* Reset the DSN flags */
1533 authenticated_sender = NULL;
1534 #ifdef EXPERIMENTAL_BRIGHTMAIL
1536 bmi_verdicts = NULL;
1538 #ifndef DISABLE_DKIM
1539 dkim_signers = NULL;
1540 dkim_disable_verify = FALSE;
1541 dkim_collect_input = FALSE;
1543 #ifdef EXPERIMENTAL_SPF
1544 spf_header_comment = NULL;
1545 spf_received = NULL;
1547 spf_smtp_comment = NULL;
1549 #ifdef EXPERIMENTAL_INTERNATIONAL
1550 message_smtputf8 = FALSE;
1552 body_linecount = body_zerocount = 0;
1554 sender_rate = sender_rate_limit = sender_rate_period = NULL;
1555 ratelimiters_mail = NULL; /* Updated by ratelimit ACL condition */
1556 /* Note that ratelimiters_conn persists across resets. */
1558 /* Reset message ACL variables */
1562 /* The message body variables use malloc store. They may be set if this is
1563 not the first message in an SMTP session and the previous message caused them
1564 to be referenced in an ACL. */
1566 if (message_body != NULL)
1568 store_free(message_body);
1569 message_body = NULL;
1572 if (message_body_end != NULL)
1574 store_free(message_body_end);
1575 message_body_end = NULL;
1578 /* Warning log messages are also saved in malloc store. They are saved to avoid
1579 repetition in the same message, but it seems right to repeat them for different
1582 while (acl_warn_logged != NULL)
1584 string_item *this = acl_warn_logged;
1585 acl_warn_logged = acl_warn_logged->next;
1594 /*************************************************
1595 * Initialize for incoming batched SMTP message *
1596 *************************************************/
1598 /* This function is called from smtp_setup_msg() in the case when
1599 smtp_batched_input is true. This happens when -bS is used to pass a whole batch
1600 of messages in one file with SMTP commands between them. All errors must be
1601 reported by sending a message, and only MAIL FROM, RCPT TO, and DATA are
1602 relevant. After an error on a sender, or an invalid recipient, the remainder
1603 of the message is skipped. The value of received_protocol is already set.
1606 Returns: > 0 message successfully started (reached DATA)
1607 = 0 QUIT read or end of file reached
1608 < 0 should not occur
1612 smtp_setup_batch_msg(void)
1615 void *reset_point = store_get(0);
1617 /* Save the line count at the start of each transaction - single commands
1618 like HELO and RSET count as whole transactions. */
1620 bsmtp_transaction_linecount = receive_linecount;
1622 if ((receive_feof)()) return 0; /* Treat EOF as QUIT */
1624 smtp_reset(reset_point); /* Reset for start of message */
1626 /* Deal with SMTP commands. This loop is exited by setting done to a POSITIVE
1627 value. The values are 2 larger than the required yield of the function. */
1632 uschar *recipient = NULL;
1633 int start, end, sender_domain, recipient_domain;
1635 switch(smtp_read_command(FALSE))
1637 /* The HELO/EHLO commands set sender_address_helo if they have
1638 valid data; otherwise they are ignored, except that they do
1639 a reset of the state. */
1644 check_helo(smtp_cmd_data);
1648 smtp_reset(reset_point);
1649 bsmtp_transaction_linecount = receive_linecount;
1653 /* The MAIL FROM command requires an address as an operand. All we
1654 do here is to parse it for syntactic correctness. The form "<>" is
1655 a special case which converts into an empty string. The start/end
1656 pointers in the original are not used further for this address, as
1657 it is the canonical extracted address which is all that is kept. */
1660 smtp_mailcmd_count++; /* Count for no-mail log */
1661 if (sender_address != NULL)
1662 /* The function moan_smtp_batch() does not return. */
1663 moan_smtp_batch(smtp_cmd_buffer, "503 Sender already given");
1665 if (smtp_cmd_data[0] == 0)
1666 /* The function moan_smtp_batch() does not return. */
1667 moan_smtp_batch(smtp_cmd_buffer, "501 MAIL FROM must have an address operand");
1669 /* Reset to start of message */
1671 smtp_reset(reset_point);
1673 /* Apply SMTP rewrite */
1675 raw_sender = ((rewrite_existflags & rewrite_smtp) != 0)?
1676 rewrite_one(smtp_cmd_data, rewrite_smtp|rewrite_smtp_sender, NULL, FALSE,
1677 US"", global_rewrite_rules) : smtp_cmd_data;
1679 /* Extract the address; the TRUE flag allows <> as valid */
1682 parse_extract_address(raw_sender, &errmess, &start, &end, &sender_domain,
1685 if (raw_sender == NULL)
1686 /* The function moan_smtp_batch() does not return. */
1687 moan_smtp_batch(smtp_cmd_buffer, "501 %s", errmess);
1689 sender_address = string_copy(raw_sender);
1691 /* Qualify unqualified sender addresses if permitted to do so. */
1693 if (sender_domain == 0 && sender_address[0] != 0 && sender_address[0] != '@')
1695 if (allow_unqualified_sender)
1697 sender_address = rewrite_address_qualify(sender_address, FALSE);
1698 DEBUG(D_receive) debug_printf("unqualified address %s accepted "
1699 "and rewritten\n", raw_sender);
1701 /* The function moan_smtp_batch() does not return. */
1702 else moan_smtp_batch(smtp_cmd_buffer, "501 sender address must contain "
1708 /* The RCPT TO command requires an address as an operand. All we do
1709 here is to parse it for syntactic correctness. There may be any number
1710 of RCPT TO commands, specifying multiple senders. We build them all into
1711 a data structure that is in argc/argv format. The start/end values
1712 given by parse_extract_address are not used, as we keep only the
1713 extracted address. */
1716 if (sender_address == NULL)
1717 /* The function moan_smtp_batch() does not return. */
1718 moan_smtp_batch(smtp_cmd_buffer, "503 No sender yet given");
1720 if (smtp_cmd_data[0] == 0)
1721 /* The function moan_smtp_batch() does not return. */
1722 moan_smtp_batch(smtp_cmd_buffer, "501 RCPT TO must have an address operand");
1724 /* Check maximum number allowed */
1726 if (recipients_max > 0 && recipients_count + 1 > recipients_max)
1727 /* The function moan_smtp_batch() does not return. */
1728 moan_smtp_batch(smtp_cmd_buffer, "%s too many recipients",
1729 recipients_max_reject? "552": "452");
1731 /* Apply SMTP rewrite, then extract address. Don't allow "<>" as a
1732 recipient address */
1734 recipient = ((rewrite_existflags & rewrite_smtp) != 0)?
1735 rewrite_one(smtp_cmd_data, rewrite_smtp, NULL, FALSE, US"",
1736 global_rewrite_rules) : smtp_cmd_data;
1738 /* rfc821_domains = TRUE; << no longer needed */
1739 recipient = parse_extract_address(recipient, &errmess, &start, &end,
1740 &recipient_domain, FALSE);
1741 /* rfc821_domains = FALSE; << no longer needed */
1743 if (recipient == NULL)
1744 /* The function moan_smtp_batch() does not return. */
1745 moan_smtp_batch(smtp_cmd_buffer, "501 %s", errmess);
1747 /* If the recipient address is unqualified, qualify it if permitted. Then
1748 add it to the list of recipients. */
1750 if (recipient_domain == 0)
1752 if (allow_unqualified_recipient)
1754 DEBUG(D_receive) debug_printf("unqualified address %s accepted\n",
1756 recipient = rewrite_address_qualify(recipient, TRUE);
1758 /* The function moan_smtp_batch() does not return. */
1759 else moan_smtp_batch(smtp_cmd_buffer, "501 recipient address must contain "
1762 receive_add_recipient(recipient, -1);
1766 /* The DATA command is legal only if it follows successful MAIL FROM
1767 and RCPT TO commands. This function is complete when a valid DATA
1768 command is encountered. */
1771 if (sender_address == NULL || recipients_count <= 0)
1773 /* The function moan_smtp_batch() does not return. */
1774 if (sender_address == NULL)
1775 moan_smtp_batch(smtp_cmd_buffer,
1776 "503 MAIL FROM:<sender> command must precede DATA");
1778 moan_smtp_batch(smtp_cmd_buffer,
1779 "503 RCPT TO:<recipient> must precede DATA");
1783 done = 3; /* DATA successfully achieved */
1784 message_ended = END_NOTENDED; /* Indicate in middle of message */
1789 /* The VRFY, EXPN, HELP, ETRN, and NOOP commands are ignored. */
1796 bsmtp_transaction_linecount = receive_linecount;
1807 /* The function moan_smtp_batch() does not return. */
1808 moan_smtp_batch(smtp_cmd_buffer, "501 Unexpected argument data");
1813 /* The function moan_smtp_batch() does not return. */
1814 moan_smtp_batch(smtp_cmd_buffer, "501 Unexpected NULL in SMTP command");
1819 /* The function moan_smtp_batch() does not return. */
1820 moan_smtp_batch(smtp_cmd_buffer, "500 Command unrecognized");
1825 return done - 2; /* Convert yield values */
1831 /*************************************************
1832 * Start an SMTP session *
1833 *************************************************/
1835 /* This function is called at the start of an SMTP session. Thereafter,
1836 smtp_setup_msg() is called to initiate each separate message. This
1837 function does host-specific testing, and outputs the banner line.
1840 Returns: FALSE if the session can not continue; something has
1841 gone wrong, or the connection to the host is blocked
1845 smtp_start_session(void)
1849 uschar *user_msg, *log_msg;
1853 smtp_connection_start = time(NULL);
1854 for (smtp_ch_index = 0; smtp_ch_index < SMTP_HBUFF_SIZE; smtp_ch_index++)
1855 smtp_connection_had[smtp_ch_index] = SCH_NONE;
1858 /* Default values for certain variables */
1860 helo_seen = esmtp = helo_accept_junk = FALSE;
1861 smtp_mailcmd_count = 0;
1862 count_nonmail = TRUE_UNSET;
1863 synprot_error_count = unknown_command_count = nonmail_command_count = 0;
1864 smtp_delay_mail = smtp_rlm_base;
1865 auth_advertised = FALSE;
1866 pipelining_advertised = FALSE;
1867 pipelining_enable = TRUE;
1868 sync_cmd_limit = NON_SYNC_CMD_NON_PIPELINING;
1869 smtp_exit_function_called = FALSE; /* For avoiding loop in not-quit exit */
1871 memset(sender_host_cache, 0, sizeof(sender_host_cache));
1873 /* If receiving by -bs from a trusted user, or testing with -bh, we allow
1874 authentication settings from -oMaa to remain in force. */
1876 if (!host_checking && !sender_host_notsocket) sender_host_authenticated = NULL;
1877 authenticated_by = NULL;
1880 tls_in.cipher = tls_in.peerdn = NULL;
1881 tls_in.ourcert = tls_in.peercert = NULL;
1883 tls_in.ocsp = OCSP_NOT_REQ;
1884 tls_advertised = FALSE;
1886 dsn_advertised = FALSE;
1887 #ifdef EXPERIMENTAL_INTERNATIONAL
1888 smtputf8_advertised = FALSE;
1891 /* Reset ACL connection variables */
1895 /* Allow for trailing 0 in the command and data buffers. */
1897 smtp_cmd_buffer = (uschar *)malloc(2*smtp_cmd_buffer_size + 2);
1898 if (smtp_cmd_buffer == NULL)
1899 log_write(0, LOG_MAIN|LOG_PANIC_DIE,
1900 "malloc() failed for SMTP command buffer");
1901 smtp_cmd_buffer[0] = 0;
1902 smtp_data_buffer = smtp_cmd_buffer + smtp_cmd_buffer_size + 1;
1904 /* For batched input, the protocol setting can be overridden from the
1905 command line by a trusted caller. */
1907 if (smtp_batched_input)
1909 if (received_protocol == NULL) received_protocol = US"local-bsmtp";
1912 /* For non-batched SMTP input, the protocol setting is forced here. It will be
1913 reset later if any of EHLO/AUTH/STARTTLS are received. */
1917 (sender_host_address ? protocols : protocols_local) [pnormal];
1919 /* Set up the buffer for inputting using direct read() calls, and arrange to
1920 call the local functions instead of the standard C ones. */
1922 smtp_inbuffer = (uschar *)malloc(in_buffer_size);
1923 if (smtp_inbuffer == NULL)
1924 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "malloc() failed for SMTP input buffer");
1925 receive_getc = smtp_getc;
1926 receive_ungetc = smtp_ungetc;
1927 receive_feof = smtp_feof;
1928 receive_ferror = smtp_ferror;
1929 receive_smtp_buffered = smtp_buffered;
1930 smtp_inptr = smtp_inend = smtp_inbuffer;
1931 smtp_had_eof = smtp_had_error = 0;
1933 /* Set up the message size limit; this may be host-specific */
1935 thismessage_size_limit = expand_string_integer(message_size_limit, TRUE);
1936 if (expand_string_message != NULL)
1938 if (thismessage_size_limit == -1)
1939 log_write(0, LOG_MAIN|LOG_PANIC, "unable to expand message_size_limit: "
1940 "%s", expand_string_message);
1942 log_write(0, LOG_MAIN|LOG_PANIC, "invalid message_size_limit: "
1943 "%s", expand_string_message);
1944 smtp_closedown(US"Temporary local problem - please try later");
1948 /* When a message is input locally via the -bs or -bS options, sender_host_
1949 unknown is set unless -oMa was used to force an IP address, in which case it
1950 is checked like a real remote connection. When -bs is used from inetd, this
1951 flag is not set, causing the sending host to be checked. The code that deals
1952 with IP source routing (if configured) is never required for -bs or -bS and
1953 the flag sender_host_notsocket is used to suppress it.
1955 If smtp_accept_max and smtp_accept_reserve are set, keep some connections in
1956 reserve for certain hosts and/or networks. */
1958 if (!sender_host_unknown)
1961 BOOL reserved_host = FALSE;
1963 /* Look up IP options (source routing info) on the socket if this is not an
1964 -oMa "host", and if any are found, log them and drop the connection.
1966 Linux (and others now, see below) is different to everyone else, so there
1967 has to be some conditional compilation here. Versions of Linux before 2.1.15
1968 used a structure whose name was "options". Somebody finally realized that
1969 this name was silly, and it got changed to "ip_options". I use the
1970 newer name here, but there is a fudge in the script that sets up os.h
1971 to define a macro in older Linux systems.
1973 Sigh. Linux is a fast-moving target. Another generation of Linux uses
1974 glibc 2, which has chosen ip_opts for the structure name. This is now
1975 really a glibc thing rather than a Linux thing, so the condition name
1976 has been changed to reflect this. It is relevant also to GNU/Hurd.
1978 Mac OS 10.x (Darwin) is like the later glibc versions, but without the
1979 setting of the __GLIBC__ macro, so we can't detect it automatically. There's
1980 a special macro defined in the os.h file.
1982 Some DGUX versions on older hardware appear not to support IP options at
1983 all, so there is now a general macro which can be set to cut out this
1986 How to do this properly in IPv6 is not yet known. */
1988 #if !HAVE_IPV6 && !defined(NO_IP_OPTIONS)
1990 #ifdef GLIBC_IP_OPTIONS
1991 #if (!defined __GLIBC__) || (__GLIBC__ < 2)
1996 #elif defined DARWIN_IP_OPTIONS
2002 if (!host_checking && !sender_host_notsocket)
2005 EXIM_SOCKLEN_T optlen = sizeof(struct ip_options) + MAX_IPOPTLEN;
2006 struct ip_options *ipopt = store_get(optlen);
2008 struct ip_opts ipoptblock;
2009 struct ip_opts *ipopt = &ipoptblock;
2010 EXIM_SOCKLEN_T optlen = sizeof(ipoptblock);
2012 struct ipoption ipoptblock;
2013 struct ipoption *ipopt = &ipoptblock;
2014 EXIM_SOCKLEN_T optlen = sizeof(ipoptblock);
2017 /* Occasional genuine failures of getsockopt() have been seen - for
2018 example, "reset by peer". Therefore, just log and give up on this
2019 call, unless the error is ENOPROTOOPT. This error is given by systems
2020 that have the interfaces but not the mechanism - e.g. GNU/Hurd at the time
2021 of writing. So for that error, carry on - we just can't do an IP options
2024 DEBUG(D_receive) debug_printf("checking for IP options\n");
2026 if (getsockopt(fileno(smtp_out), IPPROTO_IP, IP_OPTIONS, (uschar *)(ipopt),
2029 if (errno != ENOPROTOOPT)
2031 log_write(0, LOG_MAIN, "getsockopt() failed from %s: %s",
2032 host_and_ident(FALSE), strerror(errno));
2033 smtp_printf("451 SMTP service not available\r\n");
2038 /* Deal with any IP options that are set. On the systems I have looked at,
2039 the value of MAX_IPOPTLEN has been 40, meaning that there should never be
2040 more logging data than will fit in big_buffer. Nevertheless, after somebody
2041 questioned this code, I've added in some paranoid checking. */
2043 else if (optlen > 0)
2045 uschar *p = big_buffer;
2046 uschar *pend = big_buffer + big_buffer_size;
2047 uschar *opt, *adptr;
2049 struct in_addr addr;
2052 uschar *optstart = (uschar *)(ipopt->__data);
2054 uschar *optstart = (uschar *)(ipopt->ip_opts);
2056 uschar *optstart = (uschar *)(ipopt->ipopt_list);
2059 DEBUG(D_receive) debug_printf("IP options exist\n");
2061 Ustrcpy(p, "IP options on incoming call:");
2064 for (opt = optstart; opt != NULL &&
2065 opt < (uschar *)(ipopt) + optlen;)
2079 if (!string_format(p, pend-p, " %s [@%s",
2080 (*opt == IPOPT_SSRR)? "SSRR" : "LSRR",
2082 inet_ntoa(*((struct in_addr *)(&(ipopt->faddr))))))
2084 inet_ntoa(ipopt->ip_dst)))
2086 inet_ntoa(ipopt->ipopt_dst)))
2094 optcount = (opt[1] - 3) / sizeof(struct in_addr);
2096 while (optcount-- > 0)
2098 memcpy(&addr, adptr, sizeof(addr));
2099 if (!string_format(p, pend - p - 1, "%s%s",
2100 (optcount == 0)? ":" : "@", inet_ntoa(addr)))
2106 adptr += sizeof(struct in_addr);
2115 if (pend - p < 4 + 3*opt[1]) { opt = NULL; break; }
2118 for (i = 0; i < opt[1]; i++)
2120 sprintf(CS p, "%2.2x ", opt[i]);
2131 log_write(0, LOG_MAIN, "%s", big_buffer);
2133 /* Refuse any call with IP options. This is what tcpwrappers 7.5 does. */
2135 log_write(0, LOG_MAIN|LOG_REJECT,
2136 "connection from %s refused (IP options)", host_and_ident(FALSE));
2138 smtp_printf("554 SMTP service not available\r\n");
2142 /* Length of options = 0 => there are no options */
2144 else DEBUG(D_receive) debug_printf("no IP options found\n");
2146 #endif /* HAVE_IPV6 && !defined(NO_IP_OPTIONS) */
2148 /* Set keep-alive in socket options. The option is on by default. This
2149 setting is an attempt to get rid of some hanging connections that stick in
2150 read() when the remote end (usually a dialup) goes away. */
2152 if (smtp_accept_keepalive && !sender_host_notsocket)
2153 ip_keepalive(fileno(smtp_out), sender_host_address, FALSE);
2155 /* If the current host matches host_lookup, set the name by doing a
2156 reverse lookup. On failure, sender_host_name will be NULL and
2157 host_lookup_failed will be TRUE. This may or may not be serious - optional
2160 if (verify_check_host(&host_lookup) == OK)
2162 (void)host_name_lookup();
2163 host_build_sender_fullhost();
2166 /* Delay this until we have the full name, if it is looked up. */
2168 set_process_info("handling incoming connection from %s",
2169 host_and_ident(FALSE));
2171 /* Expand smtp_receive_timeout, if needed */
2173 if (smtp_receive_timeout_s)
2176 if ( !(exp = expand_string(smtp_receive_timeout_s))
2178 || (smtp_receive_timeout = readconf_readtime(exp, 0, FALSE)) < 0
2180 log_write(0, LOG_MAIN|LOG_PANIC,
2181 "bad value for smtp_receive_timeout: '%s'", exp ? exp : US"");
2184 /* Start up TLS if tls_on_connect is set. This is for supporting the legacy
2185 smtps port for use with older style SSL MTAs. */
2188 if (tls_in.on_connect && tls_server_start(tls_require_ciphers) != OK)
2192 /* Test for explicit connection rejection */
2194 if (verify_check_host(&host_reject_connection) == OK)
2196 log_write(L_connection_reject, LOG_MAIN|LOG_REJECT, "refused connection "
2197 "from %s (host_reject_connection)", host_and_ident(FALSE));
2198 smtp_printf("554 SMTP service not available\r\n");
2202 /* Test with TCP Wrappers if so configured. There is a problem in that
2203 hosts_ctl() returns 0 (deny) under a number of system failure circumstances,
2204 such as disks dying. In these cases, it is desirable to reject with a 4xx
2205 error instead of a 5xx error. There isn't a "right" way to detect such
2206 problems. The following kludge is used: errno is zeroed before calling
2207 hosts_ctl(). If the result is "reject", a 5xx error is given only if the
2208 value of errno is 0 or ENOENT (which happens if /etc/hosts.{allow,deny} does
2211 #ifdef USE_TCP_WRAPPERS
2213 tcp_wrappers_name = expand_string(tcp_wrappers_daemon_name);
2214 if (tcp_wrappers_name == NULL)
2216 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "Expansion of \"%s\" "
2217 "(tcp_wrappers_name) failed: %s", string_printing(tcp_wrappers_name),
2218 expand_string_message);
2220 if (!hosts_ctl(tcp_wrappers_name,
2221 (sender_host_name == NULL)? STRING_UNKNOWN : CS sender_host_name,
2222 (sender_host_address == NULL)? STRING_UNKNOWN : CS sender_host_address,
2223 (sender_ident == NULL)? STRING_UNKNOWN : CS sender_ident))
2225 if (errno == 0 || errno == ENOENT)
2227 HDEBUG(D_receive) debug_printf("tcp wrappers rejection\n");
2228 log_write(L_connection_reject,
2229 LOG_MAIN|LOG_REJECT, "refused connection from %s "
2230 "(tcp wrappers)", host_and_ident(FALSE));
2231 smtp_printf("554 SMTP service not available\r\n");
2235 int save_errno = errno;
2236 HDEBUG(D_receive) debug_printf("tcp wrappers rejected with unexpected "
2237 "errno value %d\n", save_errno);
2238 log_write(L_connection_reject,
2239 LOG_MAIN|LOG_REJECT, "temporarily refused connection from %s "
2240 "(tcp wrappers errno=%d)", host_and_ident(FALSE), save_errno);
2241 smtp_printf("451 Temporary local problem - please try later\r\n");
2247 /* Check for reserved slots. The value of smtp_accept_count has already been
2248 incremented to include this process. */
2250 if (smtp_accept_max > 0 &&
2251 smtp_accept_count > smtp_accept_max - smtp_accept_reserve)
2253 if ((rc = verify_check_host(&smtp_reserve_hosts)) != OK)
2255 log_write(L_connection_reject,
2256 LOG_MAIN, "temporarily refused connection from %s: not in "
2257 "reserve list: connected=%d max=%d reserve=%d%s",
2258 host_and_ident(FALSE), smtp_accept_count - 1, smtp_accept_max,
2259 smtp_accept_reserve, (rc == DEFER)? " (lookup deferred)" : "");
2260 smtp_printf("421 %s: Too many concurrent SMTP connections; "
2261 "please try again later\r\n", smtp_active_hostname);
2264 reserved_host = TRUE;
2267 /* If a load level above which only messages from reserved hosts are
2268 accepted is set, check the load. For incoming calls via the daemon, the
2269 check is done in the superior process if there are no reserved hosts, to
2270 save a fork. In all cases, the load average will already be available
2271 in a global variable at this point. */
2273 if (smtp_load_reserve >= 0 &&
2274 load_average > smtp_load_reserve &&
2276 verify_check_host(&smtp_reserve_hosts) != OK)
2278 log_write(L_connection_reject,
2279 LOG_MAIN, "temporarily refused connection from %s: not in "
2280 "reserve list and load average = %.2f", host_and_ident(FALSE),
2281 (double)load_average/1000.0);
2282 smtp_printf("421 %s: Too much load; please try again later\r\n",
2283 smtp_active_hostname);
2287 /* Determine whether unqualified senders or recipients are permitted
2288 for this host. Unfortunately, we have to do this every time, in order to
2289 set the flags so that they can be inspected when considering qualifying
2290 addresses in the headers. For a site that permits no qualification, this
2291 won't take long, however. */
2293 allow_unqualified_sender =
2294 verify_check_host(&sender_unqualified_hosts) == OK;
2296 allow_unqualified_recipient =
2297 verify_check_host(&recipient_unqualified_hosts) == OK;
2299 /* Determine whether HELO/EHLO is required for this host. The requirement
2300 can be hard or soft. */
2302 helo_required = verify_check_host(&helo_verify_hosts) == OK;
2304 helo_verify = verify_check_host(&helo_try_verify_hosts) == OK;
2306 /* Determine whether this hosts is permitted to send syntactic junk
2307 after a HELO or EHLO command. */
2309 helo_accept_junk = verify_check_host(&helo_accept_junk_hosts) == OK;
2312 /* For batch SMTP input we are now done. */
2314 if (smtp_batched_input) return TRUE;
2316 #ifdef EXPERIMENTAL_PROXY
2317 /* If valid Proxy Protocol source is connecting, set up session.
2318 * Failure will not allow any SMTP function other than QUIT. */
2319 proxy_session = FALSE;
2320 proxy_session_failed = FALSE;
2321 if (check_proxy_protocol_host())
2323 if (setup_proxy_protocol_host() == FALSE)
2325 proxy_session_failed = TRUE;
2327 debug_printf("Failure to extract proxied host, only QUIT allowed\n");
2331 sender_host_name = NULL;
2332 (void)host_name_lookup();
2333 host_build_sender_fullhost();
2338 /* Run the ACL if it exists */
2341 if (acl_smtp_connect != NULL)
2344 rc = acl_check(ACL_WHERE_CONNECT, NULL, acl_smtp_connect, &user_msg,
2348 (void)smtp_handle_acl_fail(ACL_WHERE_CONNECT, rc, user_msg, log_msg);
2353 /* Output the initial message for a two-way SMTP connection. It may contain
2354 newlines, which then cause a multi-line response to be given. */
2356 code = US"220"; /* Default status code */
2357 esc = US""; /* Default extended status code */
2358 esclen = 0; /* Length of esc */
2360 if (user_msg == NULL)
2362 s = expand_string(smtp_banner);
2364 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "Expansion of \"%s\" (smtp_banner) "
2365 "failed: %s", smtp_banner, expand_string_message);
2371 smtp_message_code(&code, &codelen, &s, NULL);
2375 esclen = codelen - 4;
2379 /* Remove any terminating newlines; might as well remove trailing space too */
2382 while (p > s && isspace(p[-1])) p--;
2385 /* It seems that CC:Mail is braindead, and assumes that the greeting message
2386 is all contained in a single IP packet. The original code wrote out the
2387 greeting using several calls to fprint/fputc, and on busy servers this could
2388 cause it to be split over more than one packet - which caused CC:Mail to fall
2389 over when it got the second part of the greeting after sending its first
2390 command. Sigh. To try to avoid this, build the complete greeting message
2391 first, and output it in one fell swoop. This gives a better chance of it
2392 ending up as a single packet. */
2394 ss = store_get(size);
2398 do /* At least once, in case we have an empty string */
2401 uschar *linebreak = Ustrchr(p, '\n');
2402 ss = string_cat(ss, &size, &ptr, code, 3);
2403 if (linebreak == NULL)
2406 ss = string_cat(ss, &size, &ptr, US" ", 1);
2410 len = linebreak - p;
2411 ss = string_cat(ss, &size, &ptr, US"-", 1);
2413 ss = string_cat(ss, &size, &ptr, esc, esclen);
2414 ss = string_cat(ss, &size, &ptr, p, len);
2415 ss = string_cat(ss, &size, &ptr, US"\r\n", 2);
2417 if (linebreak != NULL) p++;
2421 ss[ptr] = 0; /* string_cat leaves room for this */
2423 /* Before we write the banner, check that there is no input pending, unless
2424 this synchronisation check is disabled. */
2428 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP protocol "
2429 "synchronization error (input sent without waiting for greeting): "
2430 "rejected connection from %s input=\"%s\"", host_and_ident(TRUE),
2431 string_printing(smtp_inptr));
2432 smtp_printf("554 SMTP synchronization error\r\n");
2436 /* Now output the banner */
2438 smtp_printf("%s", ss);
2446 /*************************************************
2447 * Handle SMTP syntax and protocol errors *
2448 *************************************************/
2450 /* Write to the log for SMTP syntax errors in incoming commands, if configured
2451 to do so. Then transmit the error response. The return value depends on the
2452 number of syntax and protocol errors in this SMTP session.
2455 type error type, given as a log flag bit
2456 code response code; <= 0 means don't send a response
2457 data data to reflect in the response (can be NULL)
2458 errmess the error message
2460 Returns: -1 limit of syntax/protocol errors NOT exceeded
2461 +1 limit of syntax/protocol errors IS exceeded
2463 These values fit in with the values of the "done" variable in the main
2464 processing loop in smtp_setup_msg(). */
2467 synprot_error(int type, int code, uschar *data, uschar *errmess)
2471 log_write(type, LOG_MAIN, "SMTP %s error in \"%s\" %s %s",
2472 (type == L_smtp_syntax_error)? "syntax" : "protocol",
2473 string_printing(smtp_cmd_buffer), host_and_ident(TRUE), errmess);
2475 if (++synprot_error_count > smtp_max_synprot_errors)
2478 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
2479 "syntax or protocol errors (last command was \"%s\")",
2480 host_and_ident(FALSE), string_printing(smtp_cmd_buffer));
2485 smtp_printf("%d%c%s%s%s\r\n", code, (yield == 1)? '-' : ' ',
2486 (data == NULL)? US"" : data, (data == NULL)? US"" : US": ", errmess);
2488 smtp_printf("%d Too many syntax or protocol errors\r\n", code);
2497 /*************************************************
2498 * Log incomplete transactions *
2499 *************************************************/
2501 /* This function is called after a transaction has been aborted by RSET, QUIT,
2502 connection drops or other errors. It logs the envelope information received
2503 so far in order to preserve address verification attempts.
2505 Argument: string to indicate what aborted the transaction
2510 incomplete_transaction_log(uschar *what)
2512 if (sender_address == NULL || /* No transaction in progress */
2513 (log_write_selector & L_smtp_incomplete_transaction) == 0 /* Not logging */
2516 /* Build list of recipients for logging */
2518 if (recipients_count > 0)
2521 raw_recipients = store_get(recipients_count * sizeof(uschar *));
2522 for (i = 0; i < recipients_count; i++)
2523 raw_recipients[i] = recipients_list[i].address;
2524 raw_recipients_count = recipients_count;
2527 log_write(L_smtp_incomplete_transaction, LOG_MAIN|LOG_SENDER|LOG_RECIPIENTS,
2528 "%s incomplete transaction (%s)", host_and_ident(TRUE), what);
2534 /*************************************************
2535 * Send SMTP response, possibly multiline *
2536 *************************************************/
2538 /* There are, it seems, broken clients out there that cannot handle multiline
2539 responses. If no_multiline_responses is TRUE (it can be set from an ACL), we
2540 output nothing for non-final calls, and only the first line for anything else.
2543 code SMTP code, may involve extended status codes
2544 codelen length of smtp code; if > 4 there's an ESC
2545 final FALSE if the last line isn't the final line
2546 msg message text, possibly containing newlines
2552 smtp_respond(uschar* code, int codelen, BOOL final, uschar *msg)
2557 if (!final && no_multiline_responses) return;
2562 esclen = codelen - 4;
2565 /* If this is the first output for a (non-batch) RCPT command, see if all RCPTs
2566 have had the same. Note: this code is also present in smtp_printf(). It would
2567 be tidier to have it only in one place, but when it was added, it was easier to
2568 do it that way, so as not to have to mess with the code for the RCPT command,
2569 which sometimes uses smtp_printf() and sometimes smtp_respond(). */
2571 if (rcpt_in_progress)
2573 if (rcpt_smtp_response == NULL)
2574 rcpt_smtp_response = string_copy(msg);
2575 else if (rcpt_smtp_response_same &&
2576 Ustrcmp(rcpt_smtp_response, msg) != 0)
2577 rcpt_smtp_response_same = FALSE;
2578 rcpt_in_progress = FALSE;
2581 /* Not output the message, splitting it up into multiple lines if necessary. */
2585 uschar *nl = Ustrchr(msg, '\n');
2588 smtp_printf("%.3s%c%.*s%s\r\n", code, final? ' ':'-', esclen, esc, msg);
2591 else if (nl[1] == 0 || no_multiline_responses)
2593 smtp_printf("%.3s%c%.*s%.*s\r\n", code, final? ' ':'-', esclen, esc,
2594 (int)(nl - msg), msg);
2599 smtp_printf("%.3s-%.*s%.*s\r\n", code, esclen, esc, (int)(nl - msg), msg);
2601 while (isspace(*msg)) msg++;
2609 /*************************************************
2610 * Parse user SMTP message *
2611 *************************************************/
2613 /* This function allows for user messages overriding the response code details
2614 by providing a suitable response code string at the start of the message
2615 user_msg. Check the message for starting with a response code and optionally an
2616 extended status code. If found, check that the first digit is valid, and if so,
2617 change the code pointer and length to use the replacement. An invalid code
2618 causes a panic log; in this case, if the log messages is the same as the user
2619 message, we must also adjust the value of the log message to show the code that
2620 is actually going to be used (the original one).
2622 This function is global because it is called from receive.c as well as within
2625 Note that the code length returned includes the terminating whitespace
2626 character, which is always included in the regex match.
2629 code SMTP code, may involve extended status codes
2630 codelen length of smtp code; if > 4 there's an ESC
2632 log_msg optional log message, to be adjusted with the new SMTP code
2638 smtp_message_code(uschar **code, int *codelen, uschar **msg, uschar **log_msg)
2643 if (msg == NULL || *msg == NULL) return;
2645 n = pcre_exec(regex_smtp_code, NULL, CS *msg, Ustrlen(*msg), 0,
2646 PCRE_EOPT, ovector, sizeof(ovector)/sizeof(int));
2649 if ((*msg)[0] != (*code)[0])
2651 log_write(0, LOG_MAIN|LOG_PANIC, "configured error code starts with "
2652 "incorrect digit (expected %c) in \"%s\"", (*code)[0], *msg);
2653 if (log_msg != NULL && *log_msg == *msg)
2654 *log_msg = string_sprintf("%s %s", *code, *log_msg + ovector[1]);
2659 *codelen = ovector[1]; /* Includes final space */
2661 *msg += ovector[1]; /* Chop the code off the message */
2668 /*************************************************
2669 * Handle an ACL failure *
2670 *************************************************/
2672 /* This function is called when acl_check() fails. As well as calls from within
2673 this module, it is called from receive.c for an ACL after DATA. It sorts out
2674 logging the incident, and sets up the error response. A message containing
2675 newlines is turned into a multiline SMTP response, but for logging, only the
2678 There's a table of default permanent failure response codes to use in
2679 globals.c, along with the table of names. VFRY is special. Despite RFC1123 it
2680 defaults disabled in Exim. However, discussion in connection with RFC 821bis
2681 (aka RFC 2821) has concluded that the response should be 252 in the disabled
2682 state, because there are broken clients that try VRFY before RCPT. A 5xx
2683 response should be given only when the address is positively known to be
2684 undeliverable. Sigh. Also, for ETRN, 458 is given on refusal, and for AUTH,
2687 From Exim 4.63, it is possible to override the response code details by
2688 providing a suitable response code string at the start of the message provided
2689 in user_msg. The code's first digit is checked for validity.
2692 where where the ACL was called from
2694 user_msg a message that can be included in an SMTP response
2695 log_msg a message for logging
2697 Returns: 0 in most cases
2698 2 if the failure code was FAIL_DROP, in which case the
2699 SMTP connection should be dropped (this value fits with the
2700 "done" variable in smtp_setup_msg() below)
2704 smtp_handle_acl_fail(int where, int rc, uschar *user_msg, uschar *log_msg)
2706 BOOL drop = rc == FAIL_DROP;
2710 uschar *sender_info = US"";
2712 #ifdef WITH_CONTENT_SCAN
2713 (where == ACL_WHERE_MIME)? US"during MIME ACL checks" :
2715 (where == ACL_WHERE_PREDATA)? US"DATA" :
2716 (where == ACL_WHERE_DATA)? US"after DATA" :
2717 #ifndef DISABLE_PRDR
2718 (where == ACL_WHERE_PRDR)? US"after DATA PRDR" :
2720 (smtp_cmd_data == NULL)?
2721 string_sprintf("%s in \"connect\" ACL", acl_wherenames[where]) :
2722 string_sprintf("%s %s", acl_wherenames[where], smtp_cmd_data);
2724 if (drop) rc = FAIL;
2726 /* Set the default SMTP code, and allow a user message to change it. */
2728 smtp_code = (rc != FAIL)? US"451" : acl_wherecodes[where];
2729 smtp_message_code(&smtp_code, &codelen, &user_msg, &log_msg);
2731 /* We used to have sender_address here; however, there was a bug that was not
2732 updating sender_address after a rewrite during a verify. When this bug was
2733 fixed, sender_address at this point became the rewritten address. I'm not sure
2734 this is what should be logged, so I've changed to logging the unrewritten
2735 address to retain backward compatibility. */
2737 #ifndef WITH_CONTENT_SCAN
2738 if (where == ACL_WHERE_RCPT || where == ACL_WHERE_DATA)
2740 if (where == ACL_WHERE_RCPT || where == ACL_WHERE_DATA || where == ACL_WHERE_MIME)
2743 sender_info = string_sprintf("F=<%s>%s%s%s%s ",
2744 sender_address_unrewritten ? sender_address_unrewritten : sender_address,
2745 sender_host_authenticated ? US" A=" : US"",
2746 sender_host_authenticated ? sender_host_authenticated : US"",
2747 sender_host_authenticated && authenticated_id ? US":" : US"",
2748 sender_host_authenticated && authenticated_id ? authenticated_id : US""
2752 /* If there's been a sender verification failure with a specific message, and
2753 we have not sent a response about it yet, do so now, as a preliminary line for
2754 failures, but not defers. However, always log it for defer, and log it for fail
2755 unless the sender_verify_fail log selector has been turned off. */
2757 if (sender_verified_failed != NULL &&
2758 !testflag(sender_verified_failed, af_sverify_told))
2760 BOOL save_rcpt_in_progress = rcpt_in_progress;
2761 rcpt_in_progress = FALSE; /* So as not to treat these as the error */
2763 setflag(sender_verified_failed, af_sverify_told);
2765 if (rc != FAIL || (log_extra_selector & LX_sender_verify_fail) != 0)
2766 log_write(0, LOG_MAIN|LOG_REJECT, "%s sender verify %s for <%s>%s",
2767 host_and_ident(TRUE),
2768 ((sender_verified_failed->special_action & 255) == DEFER)? "defer":"fail",
2769 sender_verified_failed->address,
2770 (sender_verified_failed->message == NULL)? US"" :
2771 string_sprintf(": %s", sender_verified_failed->message));
2773 if (rc == FAIL && sender_verified_failed->user_message != NULL)
2774 smtp_respond(smtp_code, codelen, FALSE, string_sprintf(
2775 testflag(sender_verified_failed, af_verify_pmfail)?
2776 "Postmaster verification failed while checking <%s>\n%s\n"
2777 "Several RFCs state that you are required to have a postmaster\n"
2778 "mailbox for each mail domain. This host does not accept mail\n"
2779 "from domains whose servers reject the postmaster address."
2781 testflag(sender_verified_failed, af_verify_nsfail)?
2782 "Callback setup failed while verifying <%s>\n%s\n"
2783 "The initial connection, or a HELO or MAIL FROM:<> command was\n"
2784 "rejected. Refusing MAIL FROM:<> does not help fight spam, disregards\n"
2785 "RFC requirements, and stops you from receiving standard bounce\n"
2786 "messages. This host does not accept mail from domains whose servers\n"
2789 "Verification failed for <%s>\n%s",
2790 sender_verified_failed->address,
2791 sender_verified_failed->user_message));
2793 rcpt_in_progress = save_rcpt_in_progress;
2796 /* Sort out text for logging */
2798 log_msg = (log_msg == NULL)? US"" : string_sprintf(": %s", log_msg);
2799 lognl = Ustrchr(log_msg, '\n');
2800 if (lognl != NULL) *lognl = 0;
2802 /* Send permanent failure response to the command, but the code used isn't
2803 always a 5xx one - see comments at the start of this function. If the original
2804 rc was FAIL_DROP we drop the connection and yield 2. */
2806 if (rc == FAIL) smtp_respond(smtp_code, codelen, TRUE, (user_msg == NULL)?
2807 US"Administrative prohibition" : user_msg);
2809 /* Send temporary failure response to the command. Don't give any details,
2810 unless acl_temp_details is set. This is TRUE for a callout defer, a "defer"
2811 verb, and for a header verify when smtp_return_error_details is set.
2813 This conditional logic is all somewhat of a mess because of the odd
2814 interactions between temp_details and return_error_details. One day it should
2815 be re-implemented in a tidier fashion. */
2819 if (acl_temp_details && user_msg != NULL)
2821 if (smtp_return_error_details &&
2822 sender_verified_failed != NULL &&
2823 sender_verified_failed->message != NULL)
2825 smtp_respond(smtp_code, codelen, FALSE, sender_verified_failed->message);
2827 smtp_respond(smtp_code, codelen, TRUE, user_msg);
2830 smtp_respond(smtp_code, codelen, TRUE,
2831 US"Temporary local problem - please try later");
2834 /* Log the incident to the logs that are specified by log_reject_target
2835 (default main, reject). This can be empty to suppress logging of rejections. If
2836 the connection is not forcibly to be dropped, return 0. Otherwise, log why it
2837 is closing if required and return 2. */
2839 if (log_reject_target != 0)
2842 uschar * s = s_tlslog(NULL, NULL, NULL);
2847 log_write(0, log_reject_target, "%s%s %s%srejected %s%s",
2848 host_and_ident(TRUE), s,
2849 sender_info, (rc == FAIL)? US"" : US"temporarily ", what, log_msg);
2852 if (!drop) return 0;
2854 log_write(L_smtp_connection, LOG_MAIN, "%s closed by DROP in ACL",
2855 smtp_get_connection_info());
2857 /* Run the not-quit ACL, but without any custom messages. This should not be a
2858 problem, because we get here only if some other ACL has issued "drop", and
2859 in that case, *its* custom messages will have been used above. */
2861 smtp_notquit_exit(US"acl-drop", NULL, NULL);
2868 /*************************************************
2869 * Handle SMTP exit when QUIT is not given *
2870 *************************************************/
2872 /* This function provides a logging/statistics hook for when an SMTP connection
2873 is dropped on the floor or the other end goes away. It's a global function
2874 because it's called from receive.c as well as this module. As well as running
2875 the NOTQUIT ACL, if there is one, this function also outputs a final SMTP
2876 response, either with a custom message from the ACL, or using a default. There
2877 is one case, however, when no message is output - after "drop". In that case,
2878 the ACL that obeyed "drop" has already supplied the custom message, and NULL is
2879 passed to this function.
2881 In case things go wrong while processing this function, causing an error that
2882 may re-enter this funtion, there is a recursion check.
2885 reason What $smtp_notquit_reason will be set to in the ACL;
2886 if NULL, the ACL is not run
2887 code The error code to return as part of the response
2888 defaultrespond The default message if there's no user_msg
2894 smtp_notquit_exit(uschar *reason, uschar *code, uschar *defaultrespond, ...)
2897 uschar *user_msg = NULL;
2898 uschar *log_msg = NULL;
2900 /* Check for recursive acll */
2902 if (smtp_exit_function_called)
2904 log_write(0, LOG_PANIC, "smtp_notquit_exit() called more than once (%s)",
2908 smtp_exit_function_called = TRUE;
2910 /* Call the not-QUIT ACL, if there is one, unless no reason is given. */
2912 if (acl_smtp_notquit != NULL && reason != NULL)
2914 smtp_notquit_reason = reason;
2915 rc = acl_check(ACL_WHERE_NOTQUIT, NULL, acl_smtp_notquit, &user_msg,
2918 log_write(0, LOG_MAIN|LOG_PANIC, "ACL for not-QUIT returned ERROR: %s",
2922 /* Write an SMTP response if we are expected to give one. As the default
2923 responses are all internal, they should always fit in the buffer, but code a
2924 warning, just in case. Note that string_vformat() still leaves a complete
2925 string, even if it is incomplete. */
2927 if (code != NULL && defaultrespond != NULL)
2929 if (user_msg == NULL)
2933 va_start(ap, defaultrespond);
2934 if (!string_vformat(buffer, sizeof(buffer), CS defaultrespond, ap))
2935 log_write(0, LOG_MAIN|LOG_PANIC, "string too large in smtp_notquit_exit()");
2936 smtp_printf("%s %s\r\n", code, buffer);
2940 smtp_respond(code, 3, TRUE, user_msg);
2948 /*************************************************
2949 * Verify HELO argument *
2950 *************************************************/
2952 /* This function is called if helo_verify_hosts or helo_try_verify_hosts is
2953 matched. It is also called from ACL processing if verify = helo is used and
2954 verification was not previously tried (i.e. helo_try_verify_hosts was not
2955 matched). The result of its processing is to set helo_verified and
2956 helo_verify_failed. These variables should both be FALSE for this function to
2959 Note that EHLO/HELO is legitimately allowed to quote an address literal. Allow
2960 for IPv6 ::ffff: literals.
2963 Returns: TRUE if testing was completed;
2964 FALSE on a temporary failure
2968 smtp_verify_helo(void)
2972 HDEBUG(D_receive) debug_printf("verifying EHLO/HELO argument \"%s\"\n",
2975 if (sender_helo_name == NULL)
2977 HDEBUG(D_receive) debug_printf("no EHLO/HELO command was issued\n");
2980 /* Deal with the case of -bs without an IP address */
2982 else if (sender_host_address == NULL)
2984 HDEBUG(D_receive) debug_printf("no client IP address: assume success\n");
2985 helo_verified = TRUE;
2988 /* Deal with the more common case when there is a sending IP address */
2990 else if (sender_helo_name[0] == '[')
2992 helo_verified = Ustrncmp(sender_helo_name+1, sender_host_address,
2993 Ustrlen(sender_host_address)) == 0;
2998 if (strncmpic(sender_host_address, US"::ffff:", 7) == 0)
2999 helo_verified = Ustrncmp(sender_helo_name + 1,
3000 sender_host_address + 7, Ustrlen(sender_host_address) - 7) == 0;
3005 { if (helo_verified) debug_printf("matched host address\n"); }
3008 /* Do a reverse lookup if one hasn't already given a positive or negative
3009 response. If that fails, or the name doesn't match, try checking with a forward
3014 if (sender_host_name == NULL && !host_lookup_failed)
3015 yield = host_name_lookup() != DEFER;
3017 /* If a host name is known, check it and all its aliases. */
3019 if (sender_host_name)
3020 if ((helo_verified = strcmpic(sender_host_name, sender_helo_name) == 0))
3022 sender_helo_dnssec = sender_host_dnssec;
3023 HDEBUG(D_receive) debug_printf("matched host name\n");
3027 uschar **aliases = sender_host_aliases;
3029 if ((helo_verified = strcmpic(*aliases++, sender_helo_name) == 0))
3031 sender_helo_dnssec = sender_host_dnssec;
3035 HDEBUG(D_receive) if (helo_verified)
3036 debug_printf("matched alias %s\n", *(--aliases));
3039 /* Final attempt: try a forward lookup of the helo name */
3048 h.name = sender_helo_name;
3055 HDEBUG(D_receive) debug_printf("getting IP address for %s\n",
3057 rc = host_find_bydns(&h, NULL, HOST_FIND_BY_A,
3058 NULL, NULL, NULL, &d, NULL, NULL);
3059 if (rc == HOST_FOUND || rc == HOST_FOUND_LOCAL)
3060 for (hh = &h; hh; hh = hh->next)
3061 if (Ustrcmp(hh->address, sender_host_address) == 0)
3063 helo_verified = TRUE;
3064 if (h.dnssec == DS_YES) sender_helo_dnssec = TRUE;
3067 debug_printf("IP address for %s matches calling address\n"
3068 "Forward DNS security status: %sverified\n",
3069 sender_helo_name, sender_helo_dnssec ? "" : "un");
3076 if (!helo_verified) helo_verify_failed = TRUE; /* We've tried ... */
3083 /*************************************************
3084 * Send user response message *
3085 *************************************************/
3087 /* This function is passed a default response code and a user message. It calls
3088 smtp_message_code() to check and possibly modify the response code, and then
3089 calls smtp_respond() to transmit the response. I put this into a function
3090 just to avoid a lot of repetition.
3093 code the response code
3094 user_msg the user message
3100 smtp_user_msg(uschar *code, uschar *user_msg)
3103 smtp_message_code(&code, &len, &user_msg, NULL);
3104 smtp_respond(code, len, TRUE, user_msg);
3110 smtp_in_auth(auth_instance *au, uschar ** s, uschar ** ss)
3112 const uschar *set_id = NULL;
3115 /* Run the checking code, passing the remainder of the command line as
3116 data. Initials the $auth<n> variables as empty. Initialize $0 empty and set
3117 it as the only set numerical variable. The authenticator may set $auth<n>
3118 and also set other numeric variables. The $auth<n> variables are preferred
3119 nowadays; the numerical variables remain for backwards compatibility.
3121 Afterwards, have a go at expanding the set_id string, even if
3122 authentication failed - for bad passwords it can be useful to log the
3123 userid. On success, require set_id to expand and exist, and put it in
3124 authenticated_id. Save this in permanent store, as the working store gets
3125 reset at HELO, RSET, etc. */
3127 for (i = 0; i < AUTH_VARS; i++) auth_vars[i] = NULL;
3129 expand_nlength[0] = 0; /* $0 contains nothing */
3131 rc = (au->info->servercode)(au, smtp_cmd_data);
3132 if (au->set_id) set_id = expand_string(au->set_id);
3133 expand_nmax = -1; /* Reset numeric variables */
3134 for (i = 0; i < AUTH_VARS; i++) auth_vars[i] = NULL; /* Reset $auth<n> */
3136 /* The value of authenticated_id is stored in the spool file and printed in
3137 log lines. It must not contain binary zeros or newline characters. In
3138 normal use, it never will, but when playing around or testing, this error
3139 can (did) happen. To guard against this, ensure that the id contains only
3140 printing characters. */
3142 if (set_id) set_id = string_printing(set_id);
3144 /* For the non-OK cases, set up additional logging data if set_id
3148 set_id = set_id && *set_id
3149 ? string_sprintf(" (set_id=%s)", set_id) : US"";
3151 /* Switch on the result */
3156 if (!au->set_id || set_id) /* Complete success */
3158 if (set_id) authenticated_id = string_copy_malloc(set_id);
3159 sender_host_authenticated = au->name;
3160 authentication_failed = FALSE;
3161 authenticated_fail_id = NULL; /* Impossible to already be set? */
3164 (sender_host_address ? protocols : protocols_local)
3165 [pextend + pauthed + (tls_in.active >= 0 ? pcrpted:0)];
3166 *s = *ss = US"235 Authentication succeeded";
3167 authenticated_by = au;
3171 /* Authentication succeeded, but we failed to expand the set_id string.
3172 Treat this as a temporary error. */
3174 auth_defer_msg = expand_string_message;
3178 if (set_id) authenticated_fail_id = string_copy_malloc(set_id);
3179 *s = string_sprintf("435 Unable to authenticate at present%s",
3180 auth_defer_user_msg);
3181 *ss = string_sprintf("435 Unable to authenticate at present%s: %s",
3182 set_id, auth_defer_msg);
3186 *s = *ss = US"501 Invalid base64 data";
3190 *s = *ss = US"501 Authentication cancelled";
3194 *s = *ss = US"553 Initial data not expected";
3198 if (set_id) authenticated_fail_id = string_copy_malloc(set_id);
3199 *s = US"535 Incorrect authentication data";
3200 *ss = string_sprintf("535 Incorrect authentication data%s", set_id);
3204 if (set_id) authenticated_fail_id = string_copy_malloc(set_id);
3205 *s = US"435 Internal error";
3206 *ss = string_sprintf("435 Internal error%s: return %d from authentication "
3207 "check", set_id, rc);
3216 /*************************************************
3217 * Initialize for SMTP incoming message *
3218 *************************************************/
3220 /* This function conducts the initial dialogue at the start of an incoming SMTP
3221 message, and builds a list of recipients. However, if the incoming message
3222 is part of a batch (-bS option) a separate function is called since it would
3223 be messy having tests splattered about all over this function. This function
3224 therefore handles the case where interaction is occurring. The input and output
3225 files are set up in smtp_in and smtp_out.
3227 The global recipients_list is set to point to a vector of recipient_item
3228 blocks, whose number is given by recipients_count. This is extended by the
3229 receive_add_recipient() function. The global variable sender_address is set to
3230 the sender's address. The yield is +1 if a message has been successfully
3231 started, 0 if a QUIT command was encountered or the connection was refused from
3232 the particular host, or -1 if the connection was lost.
3236 Returns: > 0 message successfully started (reached DATA)
3237 = 0 QUIT read or end of file reached or call refused
3242 smtp_setup_msg(void)
3245 BOOL toomany = FALSE;
3246 BOOL discarded = FALSE;
3247 BOOL last_was_rej_mail = FALSE;
3248 BOOL last_was_rcpt = FALSE;
3249 void *reset_point = store_get(0);
3251 DEBUG(D_receive) debug_printf("smtp_setup_msg entered\n");
3253 /* Reset for start of new message. We allow one RSET not to be counted as a
3254 nonmail command, for those MTAs that insist on sending it between every
3255 message. Ditto for EHLO/HELO and for STARTTLS, to allow for going in and out of
3256 TLS between messages (an Exim client may do this if it has messages queued up
3257 for the host). Note: we do NOT reset AUTH at this point. */
3259 smtp_reset(reset_point);
3260 message_ended = END_NOTSTARTED;
3262 cmd_list[CMD_LIST_RSET].is_mail_cmd = TRUE;
3263 cmd_list[CMD_LIST_HELO].is_mail_cmd = TRUE;
3264 cmd_list[CMD_LIST_EHLO].is_mail_cmd = TRUE;
3266 cmd_list[CMD_LIST_STARTTLS].is_mail_cmd = TRUE;
3267 cmd_list[CMD_LIST_TLS_AUTH].is_mail_cmd = TRUE;
3270 /* Set the local signal handler for SIGTERM - it tries to end off tidily */
3272 os_non_restarting_signal(SIGTERM, command_sigterm_handler);
3274 /* Batched SMTP is handled in a different function. */
3276 if (smtp_batched_input) return smtp_setup_batch_msg();
3278 /* Deal with SMTP commands. This loop is exited by setting done to a POSITIVE
3279 value. The values are 2 larger than the required yield of the function. */
3283 const uschar **argv;
3284 uschar *etrn_command;
3285 uschar *etrn_serialize_key;
3287 uschar *log_msg, *smtp_code;
3288 uschar *user_msg = NULL;
3289 uschar *recipient = NULL;
3290 uschar *hello = NULL;
3292 BOOL was_rej_mail = FALSE;
3293 BOOL was_rcpt = FALSE;
3294 void (*oldsignal)(int);
3296 int start, end, sender_domain, recipient_domain;
3300 uschar *orcpt = NULL;
3303 #if defined(SUPPORT_TLS) && defined(AUTH_TLS)
3304 /* Check once per STARTTLS or SSL-on-connect for a TLS AUTH */
3305 if ( tls_in.active >= 0
3307 && tls_in.certificate_verified
3308 && cmd_list[CMD_LIST_TLS_AUTH].is_mail_cmd
3311 cmd_list[CMD_LIST_TLS_AUTH].is_mail_cmd = FALSE;
3314 rc = acl_check(ACL_WHERE_AUTH, NULL, acl_smtp_auth, &user_msg, &log_msg);
3317 done = smtp_handle_acl_fail(ACL_WHERE_AUTH, rc, user_msg, log_msg);
3322 for (au = auths; au; au = au->next)
3323 if (strcmpic(US"tls", au->driver_name) == 0)
3325 smtp_cmd_data = NULL;
3327 if ((c = smtp_in_auth(au, &s, &ss)) != OK)
3328 log_write(0, LOG_MAIN|LOG_REJECT, "%s authenticator failed for %s: %s",
3329 au->name, host_and_ident(FALSE), ss);
3331 DEBUG(D_auth) debug_printf("tls auth succeeded\n");
3338 switch(smtp_read_command(TRUE))
3340 /* The AUTH command is not permitted to occur inside a transaction, and may
3341 occur successfully only once per connection. Actually, that isn't quite
3342 true. When TLS is started, all previous information about a connection must
3343 be discarded, so a new AUTH is permitted at that time.
3345 AUTH may only be used when it has been advertised. However, it seems that
3346 there are clients that send AUTH when it hasn't been advertised, some of
3347 them even doing this after HELO. And there are MTAs that accept this. Sigh.
3348 So there's a get-out that allows this to happen.
3350 AUTH is initially labelled as a "nonmail command" so that one occurrence
3351 doesn't get counted. We change the label here so that multiple failing
3352 AUTHS will eventually hit the nonmail threshold. */
3356 authentication_failed = TRUE;
3357 cmd_list[CMD_LIST_AUTH].is_mail_cmd = FALSE;
3359 if (!auth_advertised && !allow_auth_unadvertised)
3361 done = synprot_error(L_smtp_protocol_error, 503, NULL,
3362 US"AUTH command used when not advertised");
3365 if (sender_host_authenticated)
3367 done = synprot_error(L_smtp_protocol_error, 503, NULL,
3368 US"already authenticated");
3373 done = synprot_error(L_smtp_protocol_error, 503, NULL,
3374 US"not permitted in mail transaction");
3382 rc = acl_check(ACL_WHERE_AUTH, NULL, acl_smtp_auth, &user_msg, &log_msg);
3385 done = smtp_handle_acl_fail(ACL_WHERE_AUTH, rc, user_msg, log_msg);
3390 /* Find the name of the requested authentication mechanism. */
3393 while ((c = *smtp_cmd_data) != 0 && !isspace(c))
3395 if (!isalnum(c) && c != '-' && c != '_')
3397 done = synprot_error(L_smtp_syntax_error, 501, NULL,
3398 US"invalid character in authentication mechanism name");
3404 /* If not at the end of the line, we must be at white space. Terminate the
3405 name and move the pointer on to any data that may be present. */
3407 if (*smtp_cmd_data != 0)
3409 *smtp_cmd_data++ = 0;
3410 while (isspace(*smtp_cmd_data)) smtp_cmd_data++;
3413 /* Search for an authentication mechanism which is configured for use
3414 as a server and which has been advertised (unless, sigh, allow_auth_
3415 unadvertised is set). */
3417 for (au = auths; au; au = au->next)
3418 if (strcmpic(s, au->public_name) == 0 && au->server &&
3419 (au->advertised || allow_auth_unadvertised))
3424 c = smtp_in_auth(au, &s, &ss);
3426 smtp_printf("%s\r\n", s);
3428 log_write(0, LOG_MAIN|LOG_REJECT, "%s authenticator failed for %s: %s",
3429 au->name, host_and_ident(FALSE), ss);
3432 done = synprot_error(L_smtp_protocol_error, 504, NULL,
3433 string_sprintf("%s authentication mechanism not supported", s));
3435 break; /* AUTH_CMD */
3437 /* The HELO/EHLO commands are permitted to appear in the middle of a
3438 session as well as at the beginning. They have the effect of a reset in
3439 addition to their other functions. Their absence at the start cannot be
3440 taken to be an error.
3444 If the EHLO command is not acceptable to the SMTP server, 501, 500,
3445 or 502 failure replies MUST be returned as appropriate. The SMTP
3446 server MUST stay in the same state after transmitting these replies
3447 that it was in before the EHLO was received.
3449 Therefore, we do not do the reset until after checking the command for
3450 acceptability. This change was made for Exim release 4.11. Previously
3451 it did the reset first. */
3464 HELO_EHLO: /* Common code for HELO and EHLO */
3465 cmd_list[CMD_LIST_HELO].is_mail_cmd = FALSE;
3466 cmd_list[CMD_LIST_EHLO].is_mail_cmd = FALSE;
3468 /* Reject the HELO if its argument was invalid or non-existent. A
3469 successful check causes the argument to be saved in malloc store. */
3471 if (!check_helo(smtp_cmd_data))
3473 smtp_printf("501 Syntactically invalid %s argument(s)\r\n", hello);
3475 log_write(0, LOG_MAIN|LOG_REJECT, "rejected %s from %s: syntactically "
3476 "invalid argument(s): %s", hello, host_and_ident(FALSE),
3477 (*smtp_cmd_argument == 0)? US"(no argument given)" :
3478 string_printing(smtp_cmd_argument));
3480 if (++synprot_error_count > smtp_max_synprot_errors)
3482 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
3483 "syntax or protocol errors (last command was \"%s\")",
3484 host_and_ident(FALSE), string_printing(smtp_cmd_buffer));
3491 /* If sender_host_unknown is true, we have got here via the -bs interface,
3492 not called from inetd. Otherwise, we are running an IP connection and the
3493 host address will be set. If the helo name is the primary name of this
3494 host and we haven't done a reverse lookup, force one now. If helo_required
3495 is set, ensure that the HELO name matches the actual host. If helo_verify
3496 is set, do the same check, but softly. */
3498 if (!sender_host_unknown)
3500 BOOL old_helo_verified = helo_verified;
3501 uschar *p = smtp_cmd_data;
3503 while (*p != 0 && !isspace(*p)) { *p = tolower(*p); p++; }
3506 /* Force a reverse lookup if HELO quoted something in helo_lookup_domains
3507 because otherwise the log can be confusing. */
3509 if (sender_host_name == NULL &&
3510 (deliver_domain = sender_helo_name, /* set $domain */
3511 match_isinlist(sender_helo_name, CUSS &helo_lookup_domains, 0,
3512 &domainlist_anchor, NULL, MCL_DOMAIN, TRUE, NULL)) == OK)
3513 (void)host_name_lookup();
3515 /* Rebuild the fullhost info to include the HELO name (and the real name
3516 if it was looked up.) */
3518 host_build_sender_fullhost(); /* Rebuild */
3519 set_process_info("handling%s incoming connection from %s",
3520 (tls_in.active >= 0)? " TLS" : "", host_and_ident(FALSE));
3522 /* Verify if configured. This doesn't give much security, but it does
3523 make some people happy to be able to do it. If helo_required is set,
3524 (host matches helo_verify_hosts) failure forces rejection. If helo_verify
3525 is set (host matches helo_try_verify_hosts), it does not. This is perhaps
3526 now obsolescent, since the verification can now be requested selectively
3529 helo_verified = helo_verify_failed = sender_helo_dnssec = FALSE;
3530 if (helo_required || helo_verify)
3532 BOOL tempfail = !smtp_verify_helo();
3537 smtp_printf("%d %s argument does not match calling host\r\n",
3538 tempfail? 451 : 550, hello);
3539 log_write(0, LOG_MAIN|LOG_REJECT, "%srejected \"%s %s\" from %s",
3540 tempfail? "temporarily " : "",
3541 hello, sender_helo_name, host_and_ident(FALSE));
3542 helo_verified = old_helo_verified;
3543 break; /* End of HELO/EHLO processing */
3545 HDEBUG(D_all) debug_printf("%s verification failed but host is in "
3546 "helo_try_verify_hosts\n", hello);
3551 #ifdef EXPERIMENTAL_SPF
3552 /* set up SPF context */
3553 spf_init(sender_helo_name, sender_host_address);
3556 /* Apply an ACL check if one is defined; afterwards, recheck
3557 synchronization in case the client started sending in a delay. */
3559 if (acl_smtp_helo != NULL)
3561 rc = acl_check(ACL_WHERE_HELO, NULL, acl_smtp_helo, &user_msg, &log_msg);
3564 done = smtp_handle_acl_fail(ACL_WHERE_HELO, rc, user_msg, log_msg);
3565 sender_helo_name = NULL;
3566 host_build_sender_fullhost(); /* Rebuild */
3569 else if (!check_sync()) goto SYNC_FAILURE;
3572 /* Generate an OK reply. The default string includes the ident if present,
3573 and also the IP address if present. Reflecting back the ident is intended
3574 as a deterrent to mail forgers. For maximum efficiency, and also because
3575 some broken systems expect each response to be in a single packet, arrange
3576 that the entire reply is sent in one write(). */
3578 auth_advertised = FALSE;
3579 pipelining_advertised = FALSE;
3581 tls_advertised = FALSE;
3583 dsn_advertised = FALSE;
3584 #ifdef EXPERIMENTAL_INTERNATIONAL
3585 smtputf8_advertised = FALSE;
3588 smtp_code = US"250 "; /* Default response code plus space*/
3589 if (user_msg == NULL)
3591 s = string_sprintf("%.3s %s Hello %s%s%s",
3593 smtp_active_hostname,
3594 (sender_ident == NULL)? US"" : sender_ident,
3595 (sender_ident == NULL)? US"" : US" at ",
3596 (sender_host_name == NULL)? sender_helo_name : sender_host_name);
3601 if (sender_host_address != NULL)
3603 s = string_cat(s, &size, &ptr, US" [", 2);
3604 s = string_cat(s, &size, &ptr, sender_host_address,
3605 Ustrlen(sender_host_address));
3606 s = string_cat(s, &size, &ptr, US"]", 1);
3610 /* A user-supplied EHLO greeting may not contain more than one line. Note
3611 that the code returned by smtp_message_code() includes the terminating
3612 whitespace character. */
3618 smtp_message_code(&smtp_code, &codelen, &user_msg, NULL);
3619 s = string_sprintf("%.*s%s", codelen, smtp_code, user_msg);
3620 if ((ss = strpbrk(CS s, "\r\n")) != NULL)
3622 log_write(0, LOG_MAIN|LOG_PANIC, "EHLO/HELO response must not contain "
3623 "newlines: message truncated: %s", string_printing(s));
3630 s = string_cat(s, &size, &ptr, US"\r\n", 2);
3632 /* If we received EHLO, we must create a multiline response which includes
3633 the functions supported. */
3639 /* I'm not entirely happy with this, as an MTA is supposed to check
3640 that it has enough room to accept a message of maximum size before
3641 it sends this. However, there seems little point in not sending it.
3642 The actual size check happens later at MAIL FROM time. By postponing it
3643 till then, VRFY and EXPN can be used after EHLO when space is short. */
3645 if (thismessage_size_limit > 0)
3647 sprintf(CS big_buffer, "%.3s-SIZE %d\r\n", smtp_code,
3648 thismessage_size_limit);
3649 s = string_cat(s, &size, &ptr, big_buffer, Ustrlen(big_buffer));
3653 s = string_cat(s, &size, &ptr, smtp_code, 3);
3654 s = string_cat(s, &size, &ptr, US"-SIZE\r\n", 7);
3657 /* Exim does not do protocol conversion or data conversion. It is 8-bit
3658 clean; if it has an 8-bit character in its hand, it just sends it. It
3659 cannot therefore specify 8BITMIME and remain consistent with the RFCs.
3660 However, some users want this option simply in order to stop MUAs
3661 mangling messages that contain top-bit-set characters. It is therefore
3662 provided as an option. */
3664 if (accept_8bitmime)
3666 s = string_cat(s, &size, &ptr, smtp_code, 3);
3667 s = string_cat(s, &size, &ptr, US"-8BITMIME\r\n", 11);
3670 /* Advertise DSN support if configured to do so. */
3671 if (verify_check_host(&dsn_advertise_hosts) != FAIL)
3673 s = string_cat(s, &size, &ptr, smtp_code, 3);
3674 s = string_cat(s, &size, &ptr, US"-DSN\r\n", 6);
3675 dsn_advertised = TRUE;
3678 /* Advertise ETRN if there's an ACL checking whether a host is
3679 permitted to issue it; a check is made when any host actually tries. */
3681 if (acl_smtp_etrn != NULL)
3683 s = string_cat(s, &size, &ptr, smtp_code, 3);
3684 s = string_cat(s, &size, &ptr, US"-ETRN\r\n", 7);
3687 /* Advertise EXPN if there's an ACL checking whether a host is
3688 permitted to issue it; a check is made when any host actually tries. */
3690 if (acl_smtp_expn != NULL)
3692 s = string_cat(s, &size, &ptr, smtp_code, 3);
3693 s = string_cat(s, &size, &ptr, US"-EXPN\r\n", 7);
3696 /* Exim is quite happy with pipelining, so let the other end know that
3697 it is safe to use it, unless advertising is disabled. */
3699 if (pipelining_enable &&
3700 verify_check_host(&pipelining_advertise_hosts) == OK)
3702 s = string_cat(s, &size, &ptr, smtp_code, 3);
3703 s = string_cat(s, &size, &ptr, US"-PIPELINING\r\n", 13);
3704 sync_cmd_limit = NON_SYNC_CMD_PIPELINING;
3705 pipelining_advertised = TRUE;
3709 /* If any server authentication mechanisms are configured, advertise
3710 them if the current host is in auth_advertise_hosts. The problem with
3711 advertising always is that some clients then require users to
3712 authenticate (and aren't configurable otherwise) even though it may not
3713 be necessary (e.g. if the host is in host_accept_relay).
3715 RFC 2222 states that SASL mechanism names contain only upper case
3716 letters, so output the names in upper case, though we actually recognize
3717 them in either case in the AUTH command. */
3720 #if defined(SUPPORT_TLS) && defined(AUTH_TLS)
3721 && !sender_host_authenticated
3723 && verify_check_host(&auth_advertise_hosts) == OK
3728 for (au = auths; au; au = au->next)
3729 if (au->server && (au->advertise_condition == NULL ||
3730 expand_check_condition(au->advertise_condition, au->name,
3731 US"authenticator")))
3736 s = string_cat(s, &size, &ptr, smtp_code, 3);
3737 s = string_cat(s, &size, &ptr, US"-AUTH", 5);
3739 auth_advertised = TRUE;
3742 s = string_cat(s, &size, &ptr, US" ", 1);
3743 s = string_cat(s, &size, &ptr, au->public_name,
3744 Ustrlen(au->public_name));
3745 while (++saveptr < ptr) s[saveptr] = toupper(s[saveptr]);
3746 au->advertised = TRUE;
3749 au->advertised = FALSE;
3751 if (!first) s = string_cat(s, &size, &ptr, US"\r\n", 2);
3754 /* Advertise TLS (Transport Level Security) aka SSL (Secure Socket Layer)
3755 if it has been included in the binary, and the host matches
3756 tls_advertise_hosts. We must *not* advertise if we are already in a
3757 secure connection. */
3760 if (tls_in.active < 0 &&
3761 verify_check_host(&tls_advertise_hosts) != FAIL)
3763 s = string_cat(s, &size, &ptr, smtp_code, 3);
3764 s = string_cat(s, &size, &ptr, US"-STARTTLS\r\n", 11);
3765 tls_advertised = TRUE;
3769 #ifndef DISABLE_PRDR
3770 /* Per Recipient Data Response, draft by Eric A. Hall extending RFC */
3773 s = string_cat(s, &size, &ptr, smtp_code, 3);
3774 s = string_cat(s, &size, &ptr, US"-PRDR\r\n", 7);
3778 #ifdef EXPERIMENTAL_INTERNATIONAL
3779 if ( accept_8bitmime
3780 && verify_check_host(&smtputf8_advertise_hosts) != FAIL)
3782 s = string_cat(s, &size, &ptr, smtp_code, 3);
3783 s = string_cat(s, &size, &ptr, US"-SMTPUTF8\r\n", 11);
3784 smtputf8_advertised = TRUE;
3788 /* Finish off the multiline reply with one that is always available. */
3790 s = string_cat(s, &size, &ptr, smtp_code, 3);
3791 s = string_cat(s, &size, &ptr, US" HELP\r\n", 7);
3794 /* Terminate the string (for debug), write it, and note that HELO/EHLO
3800 if (tls_in.active >= 0) (void)tls_write(TRUE, s, ptr); else
3804 int i = fwrite(s, 1, ptr, smtp_out); i = i; /* compiler quietening */
3809 while ((cr = Ustrchr(s, '\r')) != NULL) /* lose CRs */
3810 memmove(cr, cr + 1, (ptr--) - (cr - s));
3811 debug_printf("SMTP>> %s", s);
3815 /* Reset the protocol and the state, abandoning any previous message. */
3817 (sender_host_address ? protocols : protocols_local)
3819 ? pextend + (sender_host_authenticated ? pauthed : 0)
3821 + (tls_in.active >= 0 ? pcrpted : 0)
3823 smtp_reset(reset_point);
3825 break; /* HELO/EHLO */
3828 /* The MAIL command requires an address as an operand. All we do
3829 here is to parse it for syntactic correctness. The form "<>" is
3830 a special case which converts into an empty string. The start/end
3831 pointers in the original are not used further for this address, as
3832 it is the canonical extracted address which is all that is kept. */
3836 smtp_mailcmd_count++; /* Count for limit and ratelimit */
3837 was_rej_mail = TRUE; /* Reset if accepted */
3838 env_mail_type_t * mail_args; /* Sanity check & validate args */
3840 if (helo_required && !helo_seen)
3842 smtp_printf("503 HELO or EHLO required\r\n");
3843 log_write(0, LOG_MAIN|LOG_REJECT, "rejected MAIL from %s: no "
3844 "HELO/EHLO given", host_and_ident(FALSE));
3848 if (sender_address != NULL)
3850 done = synprot_error(L_smtp_protocol_error, 503, NULL,
3851 US"sender already given");
3855 if (smtp_cmd_data[0] == 0)
3857 done = synprot_error(L_smtp_protocol_error, 501, NULL,
3858 US"MAIL must have an address operand");
3862 /* Check to see if the limit for messages per connection would be
3863 exceeded by accepting further messages. */
3865 if (smtp_accept_max_per_connection > 0 &&
3866 smtp_mailcmd_count > smtp_accept_max_per_connection)
3868 smtp_printf("421 too many messages in this connection\r\n");
3869 log_write(0, LOG_MAIN|LOG_REJECT, "rejected MAIL command %s: too many "
3870 "messages in one connection", host_and_ident(TRUE));
3874 /* Reset for start of message - even if this is going to fail, we
3875 obviously need to throw away any previous data. */
3877 smtp_reset(reset_point);
3879 sender_data = recipient_data = NULL;
3881 /* Loop, checking for ESMTP additions to the MAIL FROM command. */
3885 uschar *name, *value, *end;
3886 unsigned long int size;
3887 BOOL arg_error = FALSE;
3889 if (!extract_option(&name, &value)) break;
3891 for (mail_args = env_mail_type_list;
3892 mail_args->value != ENV_MAIL_OPT_NULL;
3895 if (strcmpic(name, mail_args->name) == 0)
3897 if (mail_args->need_value && strcmpic(value, US"") == 0)
3900 switch(mail_args->value)
3902 /* Handle SIZE= by reading the value. We don't do the check till later,
3903 in order to be able to log the sender address on failure. */
3904 case ENV_MAIL_OPT_SIZE:
3905 if (((size = Ustrtoul(value, &end, 10)), *end == 0))
3907 if ((size == ULONG_MAX && errno == ERANGE) || size > INT_MAX)
3909 message_size = (int)size;
3915 /* If this session was initiated with EHLO and accept_8bitmime is set,
3916 Exim will have indicated that it supports the BODY=8BITMIME option. In
3917 fact, it does not support this according to the RFCs, in that it does not
3918 take any special action for forwarding messages containing 8-bit
3919 characters. That is why accept_8bitmime is not the default setting, but
3920 some sites want the action that is provided. We recognize both "8BITMIME"
3921 and "7BIT" as body types, but take no action. */
3922 case ENV_MAIL_OPT_BODY:
3923 if (accept_8bitmime) {
3924 if (strcmpic(value, US"8BITMIME") == 0)
3926 else if (strcmpic(value, US"7BIT") == 0)
3931 done = synprot_error(L_smtp_syntax_error, 501, NULL,
3932 US"invalid data for BODY");
3935 DEBUG(D_receive) debug_printf("8BITMIME: %d\n", body_8bitmime);
3941 /* Handle the two DSN options, but only if configured to do so (which
3942 will have caused "DSN" to be given in the EHLO response). The code itself
3943 is included only if configured in at build time. */
3945 case ENV_MAIL_OPT_RET:
3948 /* Check if RET has already been set */
3951 synprot_error(L_smtp_syntax_error, 501, NULL,
3952 US"RET can be specified once only");
3955 dsn_ret = strcmpic(value, US"HDRS") == 0
3957 : strcmpic(value, US"FULL") == 0
3960 DEBUG(D_receive) debug_printf("DSN_RET: %d\n", dsn_ret);
3961 /* Check for invalid invalid value, and exit with error */
3964 synprot_error(L_smtp_syntax_error, 501, NULL,
3965 US"Value for RET is invalid");
3970 case ENV_MAIL_OPT_ENVID:
3973 /* Check if the dsn envid has been already set */
3974 if (dsn_envid != NULL)
3976 synprot_error(L_smtp_syntax_error, 501, NULL,
3977 US"ENVID can be specified once only");
3980 dsn_envid = string_copy(value);
3981 DEBUG(D_receive) debug_printf("DSN_ENVID: %s\n", dsn_envid);
3985 /* Handle the AUTH extension. If the value given is not "<>" and either
3986 the ACL says "yes" or there is no ACL but the sending host is
3987 authenticated, we set it up as the authenticated sender. However, if the
3988 authenticator set a condition to be tested, we ignore AUTH on MAIL unless
3989 the condition is met. The value of AUTH is an xtext, which means that +,
3990 = and cntrl chars are coded in hex; however "<>" is unaffected by this
3992 case ENV_MAIL_OPT_AUTH:
3993 if (Ustrcmp(value, "<>") != 0)
3998 if (auth_xtextdecode(value, &authenticated_sender) < 0)
4000 /* Put back terminator overrides for error message */
4003 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4004 US"invalid data for AUTH");
4007 if (acl_smtp_mailauth == NULL)
4009 ignore_msg = US"client not authenticated";
4010 rc = (sender_host_authenticated != NULL)? OK : FAIL;
4014 ignore_msg = US"rejected by ACL";
4015 rc = acl_check(ACL_WHERE_MAILAUTH, NULL, acl_smtp_mailauth,
4016 &user_msg, &log_msg);
4022 if (authenticated_by == NULL ||
4023 authenticated_by->mail_auth_condition == NULL ||
4024 expand_check_condition(authenticated_by->mail_auth_condition,
4025 authenticated_by->name, US"authenticator"))
4026 break; /* Accept the AUTH */
4028 ignore_msg = US"server_mail_auth_condition failed";
4029 if (authenticated_id != NULL)
4030 ignore_msg = string_sprintf("%s: authenticated ID=\"%s\"",
4031 ignore_msg, authenticated_id);
4036 authenticated_sender = NULL;
4037 log_write(0, LOG_MAIN, "ignoring AUTH=%s from %s (%s)",
4038 value, host_and_ident(TRUE), ignore_msg);
4041 /* Should only get DEFER or ERROR here. Put back terminator
4042 overrides for error message */
4047 (void)smtp_handle_acl_fail(ACL_WHERE_MAILAUTH, rc, user_msg,
4054 #ifndef DISABLE_PRDR
4055 case ENV_MAIL_OPT_PRDR:
4057 prdr_requested = TRUE;
4061 #ifdef EXPERIMENTAL_INTERNATIONAL
4062 case ENV_MAIL_OPT_UTF8:
4063 if (smtputf8_advertised)
4065 DEBUG(D_receive) debug_printf("smtputf8 requested\n");
4066 message_smtputf8 = allow_utf8_domains = TRUE;
4067 received_protocol = string_sprintf("utf8%s", received_protocol);
4071 /* No valid option. Stick back the terminator characters and break
4072 the loop. Do the name-terminator second as extract_option sets
4073 value==name when it found no equal-sign.
4074 An error for a malformed address will occur. */
4075 case ENV_MAIL_OPT_NULL:
4083 /* Break out of for loop if switch() had bad argument or
4084 when start of the email address is reached */
4085 if (arg_error) break;
4088 /* If we have passed the threshold for rate limiting, apply the current
4089 delay, and update it for next time, provided this is a limited host. */
4091 if (smtp_mailcmd_count > smtp_rlm_threshold &&
4092 verify_check_host(&smtp_ratelimit_hosts) == OK)
4094 DEBUG(D_receive) debug_printf("rate limit MAIL: delay %.3g sec\n",
4095 smtp_delay_mail/1000.0);
4096 millisleep((int)smtp_delay_mail);
4097 smtp_delay_mail *= smtp_rlm_factor;
4098 if (smtp_delay_mail > (double)smtp_rlm_limit)
4099 smtp_delay_mail = (double)smtp_rlm_limit;
4102 /* Now extract the address, first applying any SMTP-time rewriting. The
4103 TRUE flag allows "<>" as a sender address. */
4105 raw_sender = rewrite_existflags & rewrite_smtp
4106 ? rewrite_one(smtp_cmd_data, rewrite_smtp, NULL, FALSE, US"",
4107 global_rewrite_rules)
4110 /* rfc821_domains = TRUE; << no longer needed */
4112 parse_extract_address(raw_sender, &errmess, &start, &end, &sender_domain,
4114 /* rfc821_domains = FALSE; << no longer needed */
4116 if (raw_sender == NULL)
4118 done = synprot_error(L_smtp_syntax_error, 501, smtp_cmd_data, errmess);
4122 sender_address = raw_sender;
4124 /* If there is a configured size limit for mail, check that this message
4125 doesn't exceed it. The check is postponed to this point so that the sender
4128 if (thismessage_size_limit > 0 && message_size > thismessage_size_limit)
4130 smtp_printf("552 Message size exceeds maximum permitted\r\n");
4131 log_write(L_size_reject,
4132 LOG_MAIN|LOG_REJECT, "rejected MAIL FROM:<%s> %s: "
4133 "message too big: size%s=%d max=%d",
4135 host_and_ident(TRUE),
4136 (message_size == INT_MAX)? ">" : "",
4138 thismessage_size_limit);
4139 sender_address = NULL;
4143 /* Check there is enough space on the disk unless configured not to.
4144 When smtp_check_spool_space is set, the check is for thismessage_size_limit
4145 plus the current message - i.e. we accept the message only if it won't
4146 reduce the space below the threshold. Add 5000 to the size to allow for
4147 overheads such as the Received: line and storing of recipients, etc.
4148 By putting the check here, even when SIZE is not given, it allow VRFY
4149 and EXPN etc. to be used when space is short. */
4151 if (!receive_check_fs(
4152 (smtp_check_spool_space && message_size >= 0)?
4153 message_size + 5000 : 0))
4155 smtp_printf("452 Space shortage, please try later\r\n");
4156 sender_address = NULL;
4160 /* If sender_address is unqualified, reject it, unless this is a locally
4161 generated message, or the sending host or net is permitted to send
4162 unqualified addresses - typically local machines behaving as MUAs -
4163 in which case just qualify the address. The flag is set above at the start
4164 of the SMTP connection. */
4166 if (sender_domain == 0 && sender_address[0] != 0)
4168 if (allow_unqualified_sender)
4170 sender_domain = Ustrlen(sender_address) + 1;
4171 sender_address = rewrite_address_qualify(sender_address, FALSE);
4172 DEBUG(D_receive) debug_printf("unqualified address %s accepted\n",
4177 smtp_printf("501 %s: sender address must contain a domain\r\n",
4179 log_write(L_smtp_syntax_error,
4180 LOG_MAIN|LOG_REJECT,
4181 "unqualified sender rejected: <%s> %s%s",
4183 host_and_ident(TRUE),
4185 sender_address = NULL;
4190 /* Apply an ACL check if one is defined, before responding. Afterwards,
4191 when pipelining is not advertised, do another sync check in case the ACL
4192 delayed and the client started sending in the meantime. */
4196 rc = acl_check(ACL_WHERE_MAIL, NULL, acl_smtp_mail, &user_msg, &log_msg);
4197 if (rc == OK && !pipelining_advertised && !check_sync())
4203 if (rc == OK || rc == DISCARD)
4206 smtp_printf("%s%s%s", US"250 OK",
4207 #ifndef DISABLE_PRDR
4208 prdr_requested ? US", PRDR Requested" : US"",
4215 #ifndef DISABLE_PRDR
4217 user_msg = string_sprintf("%s%s", user_msg, US", PRDR Requested");
4219 smtp_user_msg(US"250", user_msg);
4221 smtp_delay_rcpt = smtp_rlr_base;
4222 recipients_discarded = (rc == DISCARD);
4223 was_rej_mail = FALSE;
4227 done = smtp_handle_acl_fail(ACL_WHERE_MAIL, rc, user_msg, log_msg);
4228 sender_address = NULL;
4233 /* The RCPT command requires an address as an operand. There may be any
4234 number of RCPT commands, specifying multiple recipients. We build them all
4235 into a data structure. The start/end values given by parse_extract_address
4236 are not used, as we keep only the extracted address. */
4241 was_rcpt = rcpt_in_progress = TRUE;
4243 /* There must be a sender address; if the sender was rejected and
4244 pipelining was advertised, we assume the client was pipelining, and do not
4245 count this as a protocol error. Reset was_rej_mail so that further RCPTs
4246 get the same treatment. */
4248 if (sender_address == NULL)
4250 if (pipelining_advertised && last_was_rej_mail)
4252 smtp_printf("503 sender not yet given\r\n");
4253 was_rej_mail = TRUE;
4257 done = synprot_error(L_smtp_protocol_error, 503, NULL,
4258 US"sender not yet given");
4259 was_rcpt = FALSE; /* Not a valid RCPT */
4265 /* Check for an operand */
4267 if (smtp_cmd_data[0] == 0)
4269 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4270 US"RCPT must have an address operand");
4275 /* Set the DSN flags orcpt and dsn_flags from the session*/
4281 uschar *name, *value;
4283 if (!extract_option(&name, &value))
4286 if (dsn_advertised && strcmpic(name, US"ORCPT") == 0)
4288 /* Check whether orcpt has been already set */
4291 synprot_error(L_smtp_syntax_error, 501, NULL,
4292 US"ORCPT can be specified once only");
4295 orcpt = string_copy(value);
4296 DEBUG(D_receive) debug_printf("DSN orcpt: %s\n", orcpt);
4299 else if (dsn_advertised && strcmpic(name, US"NOTIFY") == 0)
4301 /* Check if the notify flags have been already set */
4304 synprot_error(L_smtp_syntax_error, 501, NULL,
4305 US"NOTIFY can be specified once only");
4308 if (strcmpic(value, US"NEVER") == 0)
4309 flags |= rf_notify_never;
4316 while (*pp != 0 && *pp != ',') pp++;
4317 if (*pp == ',') *pp++ = 0;
4318 if (strcmpic(p, US"SUCCESS") == 0)
4320 DEBUG(D_receive) debug_printf("DSN: Setting notify success\n");
4321 flags |= rf_notify_success;
4323 else if (strcmpic(p, US"FAILURE") == 0)
4325 DEBUG(D_receive) debug_printf("DSN: Setting notify failure\n");
4326 flags |= rf_notify_failure;
4328 else if (strcmpic(p, US"DELAY") == 0)
4330 DEBUG(D_receive) debug_printf("DSN: Setting notify delay\n");
4331 flags |= rf_notify_delay;
4335 /* Catch any strange values */
4336 synprot_error(L_smtp_syntax_error, 501, NULL,
4337 US"Invalid value for NOTIFY parameter");
4342 DEBUG(D_receive) debug_printf("DSN Flags: %x\n", flags);
4346 /* Unknown option. Stick back the terminator characters and break
4347 the loop. An error for a malformed address will occur. */
4351 DEBUG(D_receive) debug_printf("Invalid RCPT option: %s : %s\n", name, value);
4358 /* Apply SMTP rewriting then extract the working address. Don't allow "<>"
4359 as a recipient address */
4361 recipient = ((rewrite_existflags & rewrite_smtp) != 0)?
4362 rewrite_one(smtp_cmd_data, rewrite_smtp, NULL, FALSE, US"",
4363 global_rewrite_rules) : smtp_cmd_data;
4365 /* rfc821_domains = TRUE; << no longer needed */
4366 recipient = parse_extract_address(recipient, &errmess, &start, &end,
4367 &recipient_domain, FALSE);
4368 /* rfc821_domains = FALSE; << no longer needed */
4370 if (recipient == NULL)
4372 done = synprot_error(L_smtp_syntax_error, 501, smtp_cmd_data, errmess);
4377 /* If the recipient address is unqualified, reject it, unless this is a
4378 locally generated message. However, unqualified addresses are permitted
4379 from a configured list of hosts and nets - typically when behaving as
4380 MUAs rather than MTAs. Sad that SMTP is used for both types of traffic,
4381 really. The flag is set at the start of the SMTP connection.
4383 RFC 1123 talks about supporting "the reserved mailbox postmaster"; I always
4384 assumed this meant "reserved local part", but the revision of RFC 821 and
4385 friends now makes it absolutely clear that it means *mailbox*. Consequently
4386 we must always qualify this address, regardless. */
4388 if (recipient_domain == 0)
4390 if (allow_unqualified_recipient ||
4391 strcmpic(recipient, US"postmaster") == 0)
4393 DEBUG(D_receive) debug_printf("unqualified address %s accepted\n",
4395 recipient_domain = Ustrlen(recipient) + 1;
4396 recipient = rewrite_address_qualify(recipient, TRUE);
4401 smtp_printf("501 %s: recipient address must contain a domain\r\n",
4403 log_write(L_smtp_syntax_error,
4404 LOG_MAIN|LOG_REJECT, "unqualified recipient rejected: "
4405 "<%s> %s%s", recipient, host_and_ident(TRUE),
4411 /* Check maximum allowed */
4413 if (rcpt_count > recipients_max && recipients_max > 0)
4415 if (recipients_max_reject)
4418 smtp_printf("552 too many recipients\r\n");
4420 log_write(0, LOG_MAIN|LOG_REJECT, "too many recipients: message "
4421 "rejected: sender=<%s> %s", sender_address, host_and_ident(TRUE));
4426 smtp_printf("452 too many recipients\r\n");
4428 log_write(0, LOG_MAIN|LOG_REJECT, "too many recipients: excess "
4429 "temporarily rejected: sender=<%s> %s", sender_address,
4430 host_and_ident(TRUE));
4437 /* If we have passed the threshold for rate limiting, apply the current
4438 delay, and update it for next time, provided this is a limited host. */
4440 if (rcpt_count > smtp_rlr_threshold &&
4441 verify_check_host(&smtp_ratelimit_hosts) == OK)
4443 DEBUG(D_receive) debug_printf("rate limit RCPT: delay %.3g sec\n",
4444 smtp_delay_rcpt/1000.0);
4445 millisleep((int)smtp_delay_rcpt);
4446 smtp_delay_rcpt *= smtp_rlr_factor;
4447 if (smtp_delay_rcpt > (double)smtp_rlr_limit)
4448 smtp_delay_rcpt = (double)smtp_rlr_limit;
4451 /* If the MAIL ACL discarded all the recipients, we bypass ACL checking
4452 for them. Otherwise, check the access control list for this recipient. As
4453 there may be a delay in this, re-check for a synchronization error
4454 afterwards, unless pipelining was advertised. */
4456 if (recipients_discarded) rc = DISCARD; else
4458 rc = acl_check(ACL_WHERE_RCPT, recipient, acl_smtp_rcpt, &user_msg,
4460 if (rc == OK && !pipelining_advertised && !check_sync())
4464 /* The ACL was happy */
4468 if (user_msg == NULL) smtp_printf("250 Accepted\r\n");
4469 else smtp_user_msg(US"250", user_msg);
4470 receive_add_recipient(recipient, -1);
4472 /* Set the dsn flags in the recipients_list */
4473 recipients_list[recipients_count-1].orcpt = orcpt;
4474 recipients_list[recipients_count-1].dsn_flags = flags;
4476 DEBUG(D_receive) debug_printf("DSN: orcpt: %s flags: %d\n",
4477 recipients_list[recipients_count-1].orcpt,
4478 recipients_list[recipients_count-1].dsn_flags);
4481 /* The recipient was discarded */
4483 else if (rc == DISCARD)
4485 if (user_msg == NULL) smtp_printf("250 Accepted\r\n");
4486 else smtp_user_msg(US"250", user_msg);
4489 log_write(0, LOG_MAIN|LOG_REJECT, "%s F=<%s> RCPT %s: "
4490 "discarded by %s ACL%s%s", host_and_ident(TRUE),
4491 sender_address_unrewritten? sender_address_unrewritten : sender_address,
4492 smtp_cmd_argument, recipients_discarded? "MAIL" : "RCPT",
4493 log_msg ? US": " : US"", log_msg ? log_msg : US"");
4496 /* Either the ACL failed the address, or it was deferred. */
4500 if (rc == FAIL) rcpt_fail_count++; else rcpt_defer_count++;
4501 done = smtp_handle_acl_fail(ACL_WHERE_RCPT, rc, user_msg, log_msg);
4506 /* The DATA command is legal only if it follows successful MAIL FROM
4507 and RCPT TO commands. However, if pipelining is advertised, a bad DATA is
4508 not counted as a protocol error if it follows RCPT (which must have been
4509 rejected if there are no recipients.) This function is complete when a
4510 valid DATA command is encountered.
4512 Note concerning the code used: RFC 2821 says this:
4514 - If there was no MAIL, or no RCPT, command, or all such commands
4515 were rejected, the server MAY return a "command out of sequence"
4516 (503) or "no valid recipients" (554) reply in response to the
4519 The example in the pipelining RFC 2920 uses 554, but I use 503 here
4520 because it is the same whether pipelining is in use or not.
4522 If all the RCPT commands that precede DATA provoked the same error message
4523 (often indicating some kind of system error), it is helpful to include it
4524 with the DATA rejection (an idea suggested by Tony Finch). */
4528 if (!discarded && recipients_count <= 0)
4530 if (rcpt_smtp_response_same && rcpt_smtp_response != NULL)
4532 uschar *code = US"503";
4533 int len = Ustrlen(rcpt_smtp_response);
4534 smtp_respond(code, 3, FALSE, US"All RCPT commands were rejected with "
4536 /* Responses from smtp_printf() will have \r\n on the end */
4537 if (len > 2 && rcpt_smtp_response[len-2] == '\r')
4538 rcpt_smtp_response[len-2] = 0;
4539 smtp_respond(code, 3, FALSE, rcpt_smtp_response);
4541 if (pipelining_advertised && last_was_rcpt)
4542 smtp_printf("503 Valid RCPT command must precede DATA\r\n");
4544 done = synprot_error(L_smtp_protocol_error, 503, NULL,
4545 US"valid RCPT command must precede DATA");
4549 if (toomany && recipients_max_reject)
4551 sender_address = NULL; /* This will allow a new MAIL without RSET */
4552 sender_address_unrewritten = NULL;
4553 smtp_printf("554 Too many recipients\r\n");
4557 /* If there is an ACL, re-check the synchronization afterwards, since the
4558 ACL may have delayed. To handle cutthrough delivery enforce a dummy call
4559 to get the DATA command sent. */
4561 if (acl_smtp_predata == NULL && cutthrough.fd < 0) rc = OK; else
4563 uschar * acl= acl_smtp_predata ? acl_smtp_predata : US"accept";
4564 enable_dollar_recipients = TRUE;
4565 rc = acl_check(ACL_WHERE_PREDATA, NULL, acl, &user_msg,
4567 enable_dollar_recipients = FALSE;
4568 if (rc == OK && !check_sync()) goto SYNC_FAILURE;
4575 if (user_msg == NULL)
4576 smtp_printf("%s Enter message, ending with \".\" on a line by itself\r\n", code);
4577 else smtp_user_msg(code, user_msg);
4579 message_ended = END_NOTENDED; /* Indicate in middle of data */
4582 /* Either the ACL failed the address, or it was deferred. */
4585 done = smtp_handle_acl_fail(ACL_WHERE_PREDATA, rc, user_msg, log_msg);
4591 rc = acl_check(ACL_WHERE_VRFY, NULL, acl_smtp_vrfy, &user_msg, &log_msg);
4593 done = smtp_handle_acl_fail(ACL_WHERE_VRFY, rc, user_msg, log_msg);
4599 /* rfc821_domains = TRUE; << no longer needed */
4600 address = parse_extract_address(smtp_cmd_data, &errmess, &start, &end,
4601 &recipient_domain, FALSE);
4602 /* rfc821_domains = FALSE; << no longer needed */
4604 if (address == NULL)
4605 s = string_sprintf("501 %s", errmess);
4608 address_item *addr = deliver_make_addr(address, FALSE);
4609 switch(verify_address(addr, NULL, vopt_is_recipient | vopt_qualify, -1,
4610 -1, -1, NULL, NULL, NULL))
4613 s = string_sprintf("250 <%s> is deliverable", address);
4617 s = (addr->user_message != NULL)?
4618 string_sprintf("451 <%s> %s", address, addr->user_message) :
4619 string_sprintf("451 Cannot resolve <%s> at this time", address);
4623 s = (addr->user_message != NULL)?
4624 string_sprintf("550 <%s> %s", address, addr->user_message) :
4625 string_sprintf("550 <%s> is not deliverable", address);
4626 log_write(0, LOG_MAIN, "VRFY failed for %s %s",
4627 smtp_cmd_argument, host_and_ident(TRUE));
4632 smtp_printf("%s\r\n", s);
4639 rc = acl_check(ACL_WHERE_EXPN, NULL, acl_smtp_expn, &user_msg, &log_msg);
4641 done = smtp_handle_acl_fail(ACL_WHERE_EXPN, rc, user_msg, log_msg);
4644 BOOL save_log_testing_mode = log_testing_mode;
4645 address_test_mode = log_testing_mode = TRUE;
4646 (void) verify_address(deliver_make_addr(smtp_cmd_data, FALSE),
4647 smtp_out, vopt_is_recipient | vopt_qualify | vopt_expn, -1, -1, -1,
4649 address_test_mode = FALSE;
4650 log_testing_mode = save_log_testing_mode; /* true for -bh */
4659 if (!tls_advertised)
4661 done = synprot_error(L_smtp_protocol_error, 503, NULL,
4662 US"STARTTLS command used when not advertised");
4666 /* Apply an ACL check if one is defined */
4668 if (acl_smtp_starttls != NULL)
4670 rc = acl_check(ACL_WHERE_STARTTLS, NULL, acl_smtp_starttls, &user_msg,
4674 done = smtp_handle_acl_fail(ACL_WHERE_STARTTLS, rc, user_msg, log_msg);
4679 /* RFC 2487 is not clear on when this command may be sent, though it
4680 does state that all information previously obtained from the client
4681 must be discarded if a TLS session is started. It seems reasonble to
4682 do an implied RSET when STARTTLS is received. */
4684 incomplete_transaction_log(US"STARTTLS");
4685 smtp_reset(reset_point);
4687 cmd_list[CMD_LIST_STARTTLS].is_mail_cmd = FALSE;
4689 /* There's an attack where more data is read in past the STARTTLS command
4690 before TLS is negotiated, then assumed to be part of the secure session
4691 when used afterwards; we use segregated input buffers, so are not
4692 vulnerable, but we want to note when it happens and, for sheer paranoia,
4693 ensure that the buffer is "wiped".
4694 Pipelining sync checks will normally have protected us too, unless disabled
4695 by configuration. */
4697 if (receive_smtp_buffered())
4700 debug_printf("Non-empty input buffer after STARTTLS; naive attack?");
4701 if (tls_in.active < 0)
4702 smtp_inend = smtp_inptr = smtp_inbuffer;
4703 /* and if TLS is already active, tls_server_start() should fail */
4706 /* There is nothing we value in the input buffer and if TLS is succesfully
4707 negotiated, we won't use this buffer again; if TLS fails, we'll just read
4708 fresh content into it. The buffer contains arbitrary content from an
4709 untrusted remote source; eg: NOOP <shellcode>\r\nSTARTTLS\r\n
4710 It seems safest to just wipe away the content rather than leave it as a
4711 target to jump to. */
4713 memset(smtp_inbuffer, 0, in_buffer_size);
4715 /* Attempt to start up a TLS session, and if successful, discard all
4716 knowledge that was obtained previously. At least, that's what the RFC says,
4717 and that's what happens by default. However, in order to work round YAEB,
4718 there is an option to remember the esmtp state. Sigh.
4720 We must allow for an extra EHLO command and an extra AUTH command after
4721 STARTTLS that don't add to the nonmail command count. */
4723 if ((rc = tls_server_start(tls_require_ciphers)) == OK)
4725 if (!tls_remember_esmtp)
4726 helo_seen = esmtp = auth_advertised = pipelining_advertised = FALSE;
4727 cmd_list[CMD_LIST_EHLO].is_mail_cmd = TRUE;
4728 cmd_list[CMD_LIST_AUTH].is_mail_cmd = TRUE;
4729 cmd_list[CMD_LIST_TLS_AUTH].is_mail_cmd = TRUE;
4730 if (sender_helo_name != NULL)
4732 store_free(sender_helo_name);
4733 sender_helo_name = NULL;
4734 host_build_sender_fullhost(); /* Rebuild */
4735 set_process_info("handling incoming TLS connection from %s",
4736 host_and_ident(FALSE));
4739 (sender_host_address ? protocols : protocols_local)
4741 ? pextend + (sender_host_authenticated ? pauthed : 0)
4743 + (tls_in.active >= 0 ? pcrpted : 0)
4746 sender_host_authenticated = NULL;
4747 authenticated_id = NULL;
4748 sync_cmd_limit = NON_SYNC_CMD_NON_PIPELINING;
4749 DEBUG(D_tls) debug_printf("TLS active\n");
4750 break; /* Successful STARTTLS */
4753 /* Some local configuration problem was discovered before actually trying
4754 to do a TLS handshake; give a temporary error. */
4756 else if (rc == DEFER)
4758 smtp_printf("454 TLS currently unavailable\r\n");
4762 /* Hard failure. Reject everything except QUIT or closed connection. One
4763 cause for failure is a nested STARTTLS, in which case tls_in.active remains
4764 set, but we must still reject all incoming commands. */
4766 DEBUG(D_tls) debug_printf("TLS failed to start\n");
4769 switch(smtp_read_command(FALSE))
4772 log_write(L_smtp_connection, LOG_MAIN, "%s closed by EOF",
4773 smtp_get_connection_info());
4774 smtp_notquit_exit(US"tls-failed", NULL, NULL);
4778 /* It is perhaps arguable as to which exit ACL should be called here,
4779 but as it is probably a situation that almost never arises, it
4780 probably doesn't matter. We choose to call the real QUIT ACL, which in
4781 some sense is perhaps "right". */
4785 if (acl_smtp_quit != NULL)
4787 rc = acl_check(ACL_WHERE_QUIT, NULL, acl_smtp_quit, &user_msg,
4790 log_write(0, LOG_MAIN|LOG_PANIC, "ACL for QUIT returned ERROR: %s",
4793 if (user_msg == NULL)
4794 smtp_printf("221 %s closing connection\r\n", smtp_active_hostname);
4796 smtp_respond(US"221", 3, TRUE, user_msg);
4797 log_write(L_smtp_connection, LOG_MAIN, "%s closed by QUIT",
4798 smtp_get_connection_info());
4803 smtp_printf("554 Security failure\r\n");
4807 tls_close(TRUE, TRUE);
4812 /* The ACL for QUIT is provided for gathering statistical information or
4813 similar; it does not affect the response code, but it can supply a custom
4818 incomplete_transaction_log(US"QUIT");
4819 if (acl_smtp_quit != NULL)
4821 rc = acl_check(ACL_WHERE_QUIT, NULL, acl_smtp_quit, &user_msg, &log_msg);
4823 log_write(0, LOG_MAIN|LOG_PANIC, "ACL for QUIT returned ERROR: %s",
4826 if (user_msg == NULL)
4827 smtp_printf("221 %s closing connection\r\n", smtp_active_hostname);
4829 smtp_respond(US"221", 3, TRUE, user_msg);
4832 tls_close(TRUE, TRUE);
4836 log_write(L_smtp_connection, LOG_MAIN, "%s closed by QUIT",
4837 smtp_get_connection_info());
4843 incomplete_transaction_log(US"RSET");
4844 smtp_reset(reset_point);
4846 smtp_printf("250 Reset OK\r\n");
4847 cmd_list[CMD_LIST_RSET].is_mail_cmd = FALSE;
4853 smtp_printf("250 OK\r\n");
4857 /* Show ETRN/EXPN/VRFY if there's an ACL for checking hosts; if actually
4858 used, a check will be done for permitted hosts. Show STARTTLS only if not
4859 already in a TLS session and if it would be advertised in the EHLO
4864 smtp_printf("214-Commands supported:\r\n");
4868 Ustrcat(buffer, " AUTH");
4870 if (tls_in.active < 0 &&
4871 verify_check_host(&tls_advertise_hosts) != FAIL)
4872 Ustrcat(buffer, " STARTTLS");
4874 Ustrcat(buffer, " HELO EHLO MAIL RCPT DATA");
4875 Ustrcat(buffer, " NOOP QUIT RSET HELP");
4876 if (acl_smtp_etrn != NULL) Ustrcat(buffer, " ETRN");
4877 if (acl_smtp_expn != NULL) Ustrcat(buffer, " EXPN");
4878 if (acl_smtp_vrfy != NULL) Ustrcat(buffer, " VRFY");
4879 smtp_printf("214%s\r\n", buffer);
4885 incomplete_transaction_log(US"connection lost");
4886 smtp_notquit_exit(US"connection-lost", US"421",
4887 US"%s lost input connection", smtp_active_hostname);
4889 /* Don't log by default unless in the middle of a message, as some mailers
4890 just drop the call rather than sending QUIT, and it clutters up the logs.
4893 if (sender_address != NULL || recipients_count > 0)
4894 log_write(L_lost_incoming_connection,
4896 "unexpected %s while reading SMTP command from %s%s",
4897 sender_host_unknown? "EOF" : "disconnection",
4898 host_and_ident(FALSE), smtp_read_error);
4900 else log_write(L_smtp_connection, LOG_MAIN, "%s lost%s",
4901 smtp_get_connection_info(), smtp_read_error);
4909 if (sender_address != NULL)
4911 done = synprot_error(L_smtp_protocol_error, 503, NULL,
4912 US"ETRN is not permitted inside a transaction");
4916 log_write(L_etrn, LOG_MAIN, "ETRN %s received from %s", smtp_cmd_argument,
4917 host_and_ident(FALSE));
4919 rc = acl_check(ACL_WHERE_ETRN, NULL, acl_smtp_etrn, &user_msg, &log_msg);
4922 done = smtp_handle_acl_fail(ACL_WHERE_ETRN, rc, user_msg, log_msg);
4926 /* Compute the serialization key for this command. */
4928 etrn_serialize_key = string_sprintf("etrn-%s\n", smtp_cmd_data);
4930 /* If a command has been specified for running as a result of ETRN, we
4931 permit any argument to ETRN. If not, only the # standard form is permitted,
4932 since that is strictly the only kind of ETRN that can be implemented
4933 according to the RFC. */
4935 if (smtp_etrn_command != NULL)
4939 etrn_command = smtp_etrn_command;
4940 deliver_domain = smtp_cmd_data;
4941 rc = transport_set_up_command(&argv, smtp_etrn_command, TRUE, 0, NULL,
4942 US"ETRN processing", &error);
4943 deliver_domain = NULL;
4946 log_write(0, LOG_MAIN|LOG_PANIC, "failed to set up ETRN command: %s",
4948 smtp_printf("458 Internal failure\r\n");
4953 /* Else set up to call Exim with the -R option. */
4957 if (*smtp_cmd_data++ != '#')
4959 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4960 US"argument must begin with #");
4963 etrn_command = US"exim -R";
4964 argv = CUSS child_exec_exim(CEE_RETURN_ARGV, TRUE, NULL, TRUE, 2, US"-R",
4968 /* If we are host-testing, don't actually do anything. */
4974 debug_printf("ETRN command is: %s\n", etrn_command);
4975 debug_printf("ETRN command execution skipped\n");
4977 if (user_msg == NULL) smtp_printf("250 OK\r\n");
4978 else smtp_user_msg(US"250", user_msg);
4983 /* If ETRN queue runs are to be serialized, check the database to
4984 ensure one isn't already running. */
4986 if (smtp_etrn_serialize && !enq_start(etrn_serialize_key))
4988 smtp_printf("458 Already processing %s\r\n", smtp_cmd_data);
4992 /* Fork a child process and run the command. We don't want to have to
4993 wait for the process at any point, so set SIGCHLD to SIG_IGN before
4994 forking. It should be set that way anyway for external incoming SMTP,
4995 but we save and restore to be tidy. If serialization is required, we
4996 actually run the command in yet another process, so we can wait for it
4997 to complete and then remove the serialization lock. */
4999 oldsignal = signal(SIGCHLD, SIG_IGN);
5001 if ((pid = fork()) == 0)
5003 smtp_input = FALSE; /* This process is not associated with the */
5004 (void)fclose(smtp_in); /* SMTP call any more. */
5005 (void)fclose(smtp_out);
5007 signal(SIGCHLD, SIG_DFL); /* Want to catch child */
5009 /* If not serializing, do the exec right away. Otherwise, fork down
5010 into another process. */
5012 if (!smtp_etrn_serialize || (pid = fork()) == 0)
5014 DEBUG(D_exec) debug_print_argv(argv);
5015 exim_nullstd(); /* Ensure std{in,out,err} exist */
5016 execv(CS argv[0], (char *const *)argv);
5017 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "exec of \"%s\" (ETRN) failed: %s",
5018 etrn_command, strerror(errno));
5019 _exit(EXIT_FAILURE); /* paranoia */
5022 /* Obey this if smtp_serialize and the 2nd fork yielded non-zero. That
5023 is, we are in the first subprocess, after forking again. All we can do
5024 for a failing fork is to log it. Otherwise, wait for the 2nd process to
5025 complete, before removing the serialization. */
5028 log_write(0, LOG_MAIN|LOG_PANIC, "2nd fork for serialized ETRN "
5029 "failed: %s", strerror(errno));
5033 DEBUG(D_any) debug_printf("waiting for serialized ETRN process %d\n",
5035 (void)wait(&status);
5036 DEBUG(D_any) debug_printf("serialized ETRN process %d ended\n",
5040 enq_end(etrn_serialize_key);
5041 _exit(EXIT_SUCCESS);
5044 /* Back in the top level SMTP process. Check that we started a subprocess
5045 and restore the signal state. */
5049 log_write(0, LOG_MAIN|LOG_PANIC, "fork of process for ETRN failed: %s",
5051 smtp_printf("458 Unable to fork process\r\n");
5052 if (smtp_etrn_serialize) enq_end(etrn_serialize_key);
5056 if (user_msg == NULL) smtp_printf("250 OK\r\n");
5057 else smtp_user_msg(US"250", user_msg);
5060 signal(SIGCHLD, oldsignal);
5065 done = synprot_error(L_smtp_syntax_error, 501, NULL,
5066 US"unexpected argument data");
5070 /* This currently happens only for NULLs, but could be extended. */
5073 done = synprot_error(L_smtp_syntax_error, 0, NULL, /* Just logs */
5074 US"NULL character(s) present (shown as '?')");
5075 smtp_printf("501 NULL characters are not allowed in SMTP commands\r\n");
5081 if (smtp_inend >= smtp_inbuffer + in_buffer_size)
5082 smtp_inend = smtp_inbuffer + in_buffer_size - 1;
5083 c = smtp_inend - smtp_inptr;
5084 if (c > 150) c = 150;
5086 incomplete_transaction_log(US"sync failure");
5087 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP protocol synchronization error "
5088 "(next input sent too soon: pipelining was%s advertised): "
5089 "rejected \"%s\" %s next input=\"%s\"",
5090 pipelining_advertised? "" : " not",
5091 smtp_cmd_buffer, host_and_ident(TRUE),
5092 string_printing(smtp_inptr));
5093 smtp_notquit_exit(US"synchronization-error", US"554",
5094 US"SMTP synchronization error");
5095 done = 1; /* Pretend eof - drops connection */
5099 case TOO_MANY_NONMAIL_CMD:
5100 s = smtp_cmd_buffer;
5101 while (*s != 0 && !isspace(*s)) s++;
5102 incomplete_transaction_log(US"too many non-mail commands");
5103 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
5104 "nonmail commands (last was \"%.*s\")", host_and_ident(FALSE),
5105 (int)(s - smtp_cmd_buffer), smtp_cmd_buffer);
5106 smtp_notquit_exit(US"bad-commands", US"554", US"Too many nonmail commands");
5107 done = 1; /* Pretend eof - drops connection */
5110 #ifdef EXPERIMENTAL_PROXY
5111 case PROXY_FAIL_IGNORE_CMD:
5112 smtp_printf("503 Command refused, required Proxy negotiation failed\r\n");
5117 if (unknown_command_count++ >= smtp_max_unknown_commands)
5119 log_write(L_smtp_syntax_error, LOG_MAIN,
5120 "SMTP syntax error in \"%s\" %s %s",
5121 string_printing(smtp_cmd_buffer), host_and_ident(TRUE),
5122 US"unrecognized command");
5123 incomplete_transaction_log(US"unrecognized command");
5124 smtp_notquit_exit(US"bad-commands", US"500",
5125 US"Too many unrecognized commands");
5127 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
5128 "unrecognized commands (last was \"%s\")", host_and_ident(FALSE),
5129 string_printing(smtp_cmd_buffer));
5132 done = synprot_error(L_smtp_syntax_error, 500, NULL,
5133 US"unrecognized command");
5137 /* This label is used by goto's inside loops that want to break out to
5138 the end of the command-processing loop. */
5141 last_was_rej_mail = was_rej_mail; /* Remember some last commands for */
5142 last_was_rcpt = was_rcpt; /* protocol error handling */
5146 return done - 2; /* Convert yield values */
5151 /* End of smtp_in.c */