1 /*************************************************
2 * Exim - an Internet mail transport agent *
3 *************************************************/
5 /* Copyright (c) University of Cambridge 1995 - 2013 */
6 /* See the file NOTICE for conditions of use and distribution. */
8 /* Functions for handling an incoming SMTP call. */
14 /* Initialize for TCP wrappers if so configured. It appears that the macro
15 HAVE_IPV6 is used in some versions of the tcpd.h header, so we unset it before
16 including that header, and restore its value afterwards. */
18 #ifdef USE_TCP_WRAPPERS
21 #define EXIM_HAVE_IPV6
27 #define HAVE_IPV6 TRUE
30 int allow_severity = LOG_INFO;
31 int deny_severity = LOG_NOTICE;
32 uschar *tcp_wrappers_name;
36 /* Size of buffer for reading SMTP commands. We used to use 512, as defined
37 by RFC 821. However, RFC 1869 specifies that this must be increased for SMTP
38 commands that accept arguments, and this in particular applies to AUTH, where
39 the data can be quite long. More recently this value was 2048 in Exim;
40 however, RFC 4954 (circa 2007) recommends 12288 bytes to handle AUTH. Clients
41 such as Thunderbird will send an AUTH with an initial-response for GSSAPI.
42 The maximum size of a Kerberos ticket under Windows 2003 is 12000 bytes, and
43 we need room to handle large base64-encoded AUTHs for GSSAPI.
46 #define smtp_cmd_buffer_size 16384
48 /* Size of buffer for reading SMTP incoming packets */
50 #define in_buffer_size 8192
52 /* Structure for SMTP command list */
59 short int is_mail_cmd;
62 /* Codes for identifying commands. We order them so that those that come first
63 are those for which synchronization is always required. Checking this can help
67 /* These commands are required to be synchronized, i.e. to be the last in a
68 block of commands when pipelining. */
70 HELO_CMD, EHLO_CMD, DATA_CMD, /* These are listed in the pipelining */
71 VRFY_CMD, EXPN_CMD, NOOP_CMD, /* RFC as requiring synchronization */
72 ETRN_CMD, /* This by analogy with TURN from the RFC */
73 STARTTLS_CMD, /* Required by the STARTTLS RFC */
75 /* This is a dummy to identify the non-sync commands when pipelining */
77 NON_SYNC_CMD_PIPELINING,
79 /* These commands need not be synchronized when pipelining */
81 MAIL_CMD, RCPT_CMD, RSET_CMD,
83 /* This is a dummy to identify the non-sync commands when not pipelining */
85 NON_SYNC_CMD_NON_PIPELINING,
87 /* I have been unable to find a statement about the use of pipelining
88 with AUTH, so to be on the safe side it is here, though I kind of feel
89 it should be up there with the synchronized commands. */
93 /* I'm not sure about these, but I don't think they matter. */
97 #ifdef EXPERIMENTAL_PROXY
98 PROXY_FAIL_IGNORE_CMD,
101 /* These are specials that don't correspond to actual commands */
103 EOF_CMD, OTHER_CMD, BADARG_CMD, BADCHAR_CMD, BADSYN_CMD,
104 TOO_MANY_NONMAIL_CMD };
107 /* This is a convenience macro for adding the identity of an SMTP command
108 to the circular buffer that holds a list of the last n received. */
111 smtp_connection_had[smtp_ch_index++] = n; \
112 if (smtp_ch_index >= SMTP_HBUFF_SIZE) smtp_ch_index = 0
115 /*************************************************
116 * Local static variables *
117 *************************************************/
119 static auth_instance *authenticated_by;
120 static BOOL auth_advertised;
122 static BOOL tls_advertised;
125 static BOOL helo_required = FALSE;
126 static BOOL helo_verify = FALSE;
127 static BOOL helo_seen;
128 static BOOL helo_accept_junk;
129 static BOOL count_nonmail;
130 static BOOL pipelining_advertised;
131 static BOOL rcpt_smtp_response_same;
132 static BOOL rcpt_in_progress;
133 static int nonmail_command_count;
134 static BOOL smtp_exit_function_called = 0;
135 static int synprot_error_count;
136 static int unknown_command_count;
137 static int sync_cmd_limit;
138 static int smtp_write_error = 0;
140 static uschar *rcpt_smtp_response;
141 static uschar *smtp_data_buffer;
142 static uschar *smtp_cmd_data;
144 /* We need to know the position of RSET, HELO, EHLO, AUTH, and STARTTLS. Their
145 final fields of all except AUTH are forced TRUE at the start of a new message
146 setup, to allow one of each between messages that is not counted as a nonmail
147 command. (In fact, only one of HELO/EHLO is not counted.) Also, we have to
148 allow a new EHLO after starting up TLS.
150 AUTH is "falsely" labelled as a mail command initially, so that it doesn't get
151 counted. However, the flag is changed when AUTH is received, so that multiple
152 failing AUTHs will eventually hit the limit. After a successful AUTH, another
153 AUTH is already forbidden. After a TLS session is started, AUTH's flag is again
154 forced TRUE, to allow for the re-authentication that can happen at that point.
156 QUIT is also "falsely" labelled as a mail command so that it doesn't up the
157 count of non-mail commands and possibly provoke an error. */
159 static smtp_cmd_list cmd_list[] = {
160 { "rset", sizeof("rset")-1, RSET_CMD, FALSE, FALSE }, /* First */
161 { "helo", sizeof("helo")-1, HELO_CMD, TRUE, FALSE },
162 { "ehlo", sizeof("ehlo")-1, EHLO_CMD, TRUE, FALSE },
163 { "auth", sizeof("auth")-1, AUTH_CMD, TRUE, TRUE },
165 { "starttls", sizeof("starttls")-1, STARTTLS_CMD, FALSE, FALSE },
168 /* If you change anything above here, also fix the definitions below. */
170 { "mail from:", sizeof("mail from:")-1, MAIL_CMD, TRUE, TRUE },
171 { "rcpt to:", sizeof("rcpt to:")-1, RCPT_CMD, TRUE, TRUE },
172 { "data", sizeof("data")-1, DATA_CMD, FALSE, TRUE },
173 { "quit", sizeof("quit")-1, QUIT_CMD, FALSE, TRUE },
174 { "noop", sizeof("noop")-1, NOOP_CMD, TRUE, FALSE },
175 { "etrn", sizeof("etrn")-1, ETRN_CMD, TRUE, FALSE },
176 { "vrfy", sizeof("vrfy")-1, VRFY_CMD, TRUE, FALSE },
177 { "expn", sizeof("expn")-1, EXPN_CMD, TRUE, FALSE },
178 { "help", sizeof("help")-1, HELP_CMD, TRUE, FALSE }
181 static smtp_cmd_list *cmd_list_end =
182 cmd_list + sizeof(cmd_list)/sizeof(smtp_cmd_list);
184 #define CMD_LIST_RSET 0
185 #define CMD_LIST_HELO 1
186 #define CMD_LIST_EHLO 2
187 #define CMD_LIST_AUTH 3
188 #define CMD_LIST_STARTTLS 4
190 /* This list of names is used for performing the smtp_no_mail logging action.
191 It must be kept in step with the SCH_xxx enumerations. */
193 static uschar *smtp_names[] =
195 US"NONE", US"AUTH", US"DATA", US"EHLO", US"ETRN", US"EXPN", US"HELO",
196 US"HELP", US"MAIL", US"NOOP", US"QUIT", US"RCPT", US"RSET", US"STARTTLS",
199 static uschar *protocols[] = {
200 US"local-smtp", /* HELO */
201 US"local-smtps", /* The rare case EHLO->STARTTLS->HELO */
202 US"local-esmtp", /* EHLO */
203 US"local-esmtps", /* EHLO->STARTTLS->EHLO */
204 US"local-esmtpa", /* EHLO->AUTH */
205 US"local-esmtpsa" /* EHLO->STARTTLS->EHLO->AUTH */
210 #define pcrpted 1 /* added to pextend or pnormal */
211 #define pauthed 2 /* added to pextend */
212 #define pnlocal 6 /* offset to remove "local" */
214 /* Sanity check and validate optional args to MAIL FROM: envelope */
216 ENV_MAIL_OPT_SIZE, ENV_MAIL_OPT_BODY, ENV_MAIL_OPT_AUTH,
217 #ifdef EXPERIMENTAL_PRDR
223 uschar * name; /* option requested during MAIL cmd */
224 int value; /* enum type */
225 BOOL need_value; /* TRUE requires value (name=value pair format)
226 FALSE is a singleton */
228 static env_mail_type_t env_mail_type_list[] = {
229 { US"SIZE", ENV_MAIL_OPT_SIZE, TRUE },
230 { US"BODY", ENV_MAIL_OPT_BODY, TRUE },
231 { US"AUTH", ENV_MAIL_OPT_AUTH, TRUE },
232 #ifdef EXPERIMENTAL_PRDR
233 { US"PRDR", ENV_MAIL_OPT_PRDR, FALSE },
235 { US"NULL", ENV_MAIL_OPT_NULL, FALSE }
238 /* When reading SMTP from a remote host, we have to use our own versions of the
239 C input-reading functions, in order to be able to flush the SMTP output only
240 when about to read more data from the socket. This is the only way to get
241 optimal performance when the client is using pipelining. Flushing for every
242 command causes a separate packet and reply packet each time; saving all the
243 responses up (when pipelining) combines them into one packet and one response.
245 For simplicity, these functions are used for *all* SMTP input, not only when
246 receiving over a socket. However, after setting up a secure socket (SSL), input
247 is read via the OpenSSL library, and another set of functions is used instead
250 These functions are set in the receive_getc etc. variables and called with the
251 same interface as the C functions. However, since there can only ever be
252 one incoming SMTP call, we just use a single buffer and flags. There is no need
253 to implement a complicated private FILE-like structure.*/
255 static uschar *smtp_inbuffer;
256 static uschar *smtp_inptr;
257 static uschar *smtp_inend;
258 static int smtp_had_eof;
259 static int smtp_had_error;
262 /*************************************************
263 * SMTP version of getc() *
264 *************************************************/
266 /* This gets the next byte from the SMTP input buffer. If the buffer is empty,
267 it flushes the output, and refills the buffer, with a timeout. The signal
268 handler is set appropriately by the calling function. This function is not used
269 after a connection has negotated itself into an TLS/SSL state.
272 Returns: the next character or EOF
278 if (smtp_inptr >= smtp_inend)
282 if (smtp_receive_timeout > 0) alarm(smtp_receive_timeout);
283 rc = read(fileno(smtp_in), smtp_inbuffer, in_buffer_size);
288 /* Must put the error text in fixed store, because this might be during
289 header reading, where it releases unused store above the header. */
292 smtp_had_error = save_errno;
293 smtp_read_error = string_copy_malloc(
294 string_sprintf(" (error: %s)", strerror(save_errno)));
296 else smtp_had_eof = 1;
300 dkim_exim_verify_feed(smtp_inbuffer, rc);
302 smtp_inend = smtp_inbuffer + rc;
303 smtp_inptr = smtp_inbuffer;
305 return *smtp_inptr++;
310 /*************************************************
311 * SMTP version of ungetc() *
312 *************************************************/
314 /* Puts a character back in the input buffer. Only ever
320 Returns: the character
326 *(--smtp_inptr) = ch;
333 /*************************************************
334 * SMTP version of feof() *
335 *************************************************/
337 /* Tests for a previous EOF
340 Returns: non-zero if the eof flag is set
352 /*************************************************
353 * SMTP version of ferror() *
354 *************************************************/
356 /* Tests for a previous read error, and returns with errno
357 restored to what it was when the error was detected.
360 Returns: non-zero if the error flag is set
366 errno = smtp_had_error;
367 return smtp_had_error;
372 /*************************************************
373 * Test for characters in the SMTP buffer *
374 *************************************************/
376 /* Used at the end of a message
385 return smtp_inptr < smtp_inend;
390 /*************************************************
391 * Write formatted string to SMTP channel *
392 *************************************************/
394 /* This is a separate function so that we don't have to repeat everything for
395 TLS support or debugging. It is global so that the daemon and the
396 authentication functions can use it. It does not return any error indication,
397 because major problems such as dropped connections won't show up till an output
398 flush for non-TLS connections. The smtp_fflush() function is available for
399 checking that: for convenience, TLS output errors are remembered here so that
400 they are also picked up later by smtp_fflush().
404 ... optional arguments
410 smtp_printf(const char *format, ...)
414 va_start(ap, format);
415 smtp_vprintf(format, ap);
419 /* This is split off so that verify.c:respond_printf() can, in effect, call
420 smtp_printf(), bearing in mind that in C a vararg function can't directly
421 call another vararg function, only a function which accepts a va_list. */
424 smtp_vprintf(const char *format, va_list ap)
428 yield = string_vformat(big_buffer, big_buffer_size, format, ap);
432 void *reset_point = store_get(0);
433 uschar *msg_copy, *cr, *end;
434 msg_copy = string_copy(big_buffer);
435 end = msg_copy + Ustrlen(msg_copy);
436 while ((cr = Ustrchr(msg_copy, '\r')) != NULL) /* lose CRs */
437 memmove(cr, cr + 1, (end--) - cr);
438 debug_printf("SMTP>> %s", msg_copy);
439 store_reset(reset_point);
444 log_write(0, LOG_MAIN|LOG_PANIC, "string too large in smtp_printf()");
445 smtp_closedown(US"Unexpected error");
446 exim_exit(EXIT_FAILURE);
449 /* If this is the first output for a (non-batch) RCPT command, see if all RCPTs
450 have had the same. Note: this code is also present in smtp_respond(). It would
451 be tidier to have it only in one place, but when it was added, it was easier to
452 do it that way, so as not to have to mess with the code for the RCPT command,
453 which sometimes uses smtp_printf() and sometimes smtp_respond(). */
455 if (rcpt_in_progress)
457 if (rcpt_smtp_response == NULL)
458 rcpt_smtp_response = string_copy(big_buffer);
459 else if (rcpt_smtp_response_same &&
460 Ustrcmp(rcpt_smtp_response, big_buffer) != 0)
461 rcpt_smtp_response_same = FALSE;
462 rcpt_in_progress = FALSE;
465 /* Now write the string */
468 if (tls_in.active >= 0)
470 if (tls_write(TRUE, big_buffer, Ustrlen(big_buffer)) < 0)
471 smtp_write_error = -1;
476 if (fprintf(smtp_out, "%s", big_buffer) < 0) smtp_write_error = -1;
481 /*************************************************
482 * Flush SMTP out and check for error *
483 *************************************************/
485 /* This function isn't currently used within Exim (it detects errors when it
486 tries to read the next SMTP input), but is available for use in local_scan().
487 For non-TLS connections, it flushes the output and checks for errors. For
488 TLS-connections, it checks for a previously-detected TLS write error.
491 Returns: 0 for no error; -1 after an error
497 if (tls_in.active < 0 && fflush(smtp_out) != 0) smtp_write_error = -1;
498 return smtp_write_error;
503 /*************************************************
504 * SMTP command read timeout *
505 *************************************************/
507 /* Signal handler for timing out incoming SMTP commands. This attempts to
510 Argument: signal number (SIGALRM)
515 command_timeout_handler(int sig)
517 sig = sig; /* Keep picky compilers happy */
518 log_write(L_lost_incoming_connection,
519 LOG_MAIN, "SMTP command timeout on%s connection from %s",
520 (tls_in.active >= 0)? " TLS" : "",
521 host_and_ident(FALSE));
522 if (smtp_batched_input)
523 moan_smtp_batch(NULL, "421 SMTP command timeout"); /* Does not return */
524 smtp_notquit_exit(US"command-timeout", US"421",
525 US"%s: SMTP command timeout - closing connection", smtp_active_hostname);
526 exim_exit(EXIT_FAILURE);
531 /*************************************************
533 *************************************************/
535 /* Signal handler for handling SIGTERM. Again, try to finish tidily.
537 Argument: signal number (SIGTERM)
542 command_sigterm_handler(int sig)
544 sig = sig; /* Keep picky compilers happy */
545 log_write(0, LOG_MAIN, "%s closed after SIGTERM", smtp_get_connection_info());
546 if (smtp_batched_input)
547 moan_smtp_batch(NULL, "421 SIGTERM received"); /* Does not return */
548 smtp_notquit_exit(US"signal-exit", US"421",
549 US"%s: Service not available - closing connection", smtp_active_hostname);
550 exim_exit(EXIT_FAILURE);
556 #ifdef EXPERIMENTAL_PROXY
557 /*************************************************
558 * Restore socket timeout to previous value *
559 *************************************************/
560 /* If the previous value was successfully retrieved, restore
561 it before returning control to the non-proxy routines
563 Arguments: fd - File descriptor for input
564 get_ok - Successfully retrieved previous values
565 tvtmp - Time struct with previous values
566 vslen - Length of time struct
570 restore_socket_timeout(int fd, int get_ok, struct timeval tvtmp, socklen_t vslen)
573 setsockopt(fd, SOL_SOCKET, SO_RCVTIMEO, (char *)&tvtmp, vslen);
576 /*************************************************
577 * Check if host is required proxy host *
578 *************************************************/
579 /* The function determines if inbound host will be a regular smtp host
580 or if it is configured that it must use Proxy Protocol.
587 check_proxy_protocol_host()
590 /* Cannot configure local connection as a proxy inbound */
591 if (sender_host_address == NULL) return proxy_session;
593 rc = verify_check_this_host(&proxy_required_hosts, NULL, NULL,
594 sender_host_address, NULL);
598 debug_printf("Detected proxy protocol configured host\n");
599 proxy_session = TRUE;
601 return proxy_session;
605 /*************************************************
606 * Flush waiting input string *
607 *************************************************/
614 while (rc != '\n') /* End of input string */
621 /*************************************************
622 * Setup host for proxy protocol *
623 *************************************************/
624 /* The function configures the connection based on a header from the
625 inbound host to use Proxy Protocol. The specification is very exact
626 so exit with an error if do not find the exact required pieces. This
627 includes an incorrect number of spaces separating args.
634 setup_proxy_protocol_host()
647 struct { /* TCP/UDP over IPv4, len = 12 */
653 struct { /* TCP/UDP over IPv6, len = 36 */
654 uint8_t src_addr[16];
655 uint8_t dst_addr[16];
659 struct { /* AF_UNIX sockets, len = 216 */
660 uschar src_addr[108];
661 uschar dst_addr[108];
669 const char v2sig[13] = "\x0D\x0A\x0D\x0A\x00\x0D\x0A\x51\x55\x49\x54\x0A\x02";
670 uschar *iptype; /* To display debug info */
674 struct timeval tvtmp;
676 vslen = sizeof(struct timeval);
678 fd = fileno(smtp_in);
680 /* Save current socket timeout values */
681 get_ok = getsockopt(fd, SOL_SOCKET, SO_RCVTIMEO, (char *)&tvtmp,
684 /* Proxy Protocol host must send header within a short time
685 (default 3 seconds) or it's considered invalid */
686 tv.tv_sec = PROXY_NEGOTIATION_TIMEOUT_SEC;
687 tv.tv_usec = PROXY_NEGOTIATION_TIMEOUT_USEC;
688 setsockopt(fd, SOL_SOCKET, SO_RCVTIMEO, (char *)&tv,
689 sizeof(struct timeval));
693 ret = recv(fd, &hdr, sizeof(hdr), MSG_PEEK);
695 while (ret == -1 && errno == EINTR);
699 restore_socket_timeout(fd, get_ok, tvtmp, vslen);
700 return (errno == EAGAIN) ? 0 : ERRNO_PROXYFAIL;
704 memcmp(&hdr.v2, v2sig, 13) == 0)
706 DEBUG(D_receive) debug_printf("Detected PROXYv2 header\n");
707 size = 16 + hdr.v2.len;
710 DEBUG(D_receive) debug_printf("Truncated or too large PROXYv2 header\n");
715 case 0x01: /* PROXY command */
718 case 0x11: /* TCPv4 */
719 tmpip = string_sprintf("%s", hdr.v2.addr.ip4.src_addr);
720 if (!string_is_ip_address(tmpip,NULL))
721 return ERRNO_PROXYFAIL;
722 sender_host_address = tmpip;
723 sender_host_port = hdr.v2.addr.ip4.src_port;
725 case 0x21: /* TCPv6 */
726 tmpip = string_sprintf("%s", hdr.v2.addr.ip6.src_addr);
727 if (!string_is_ip_address(tmpip,NULL))
728 return ERRNO_PROXYFAIL;
729 sender_host_address = tmpip;
730 sender_host_port = hdr.v2.addr.ip6.src_port;
733 /* Unsupported protocol, keep local connection address */
735 case 0x00: /* LOCAL command */
736 /* Keep local connection address for LOCAL */
739 DEBUG(D_receive) debug_printf("Unsupported PROXYv2 command\n");
744 memcmp(hdr.v1.line, "PROXY", 5) == 0)
746 uschar *p = string_copy(hdr.v1.line);
747 uschar *end = memchr(p, '\r', ret - 1);
748 uschar *sp; /* Utility variables follow */
752 if (!end || end[1] != '\n')
754 DEBUG(D_receive) debug_printf("Partial or invalid PROXY header\n");
757 *end = '\0'; /* Terminate the string */
758 size = end + 2 - hdr.v1.line; /* Skip header + CRLF */
759 DEBUG(D_receive) debug_printf("Detected PROXYv1 header\n");
760 /* Step through the string looking for the required fields. Ensure
761 strict adherance to required formatting, exit for any error. */
763 if (!isspace(*(p++)))
765 DEBUG(D_receive) debug_printf("Missing space after PROXY command\n");
768 if (!Ustrncmp(p, CCS"TCP4", 4))
770 else if (!Ustrncmp(p,CCS"TCP6", 4))
772 else if (!Ustrncmp(p,CCS"UNKNOWN", 7))
774 iptype = US"Unknown";
779 DEBUG(D_receive) debug_printf("Invalid TCP type\n");
783 p += Ustrlen(iptype);
784 if (!isspace(*(p++)))
786 DEBUG(D_receive) debug_printf("Missing space after TCP4/6 command\n");
789 /* Find the end of the arg */
790 if ((sp = Ustrchr(p, ' ')) == NULL)
793 debug_printf("Did not find proxied src %s\n", iptype);
797 if(!string_is_ip_address(p,NULL))
800 debug_printf("Proxied src arg is not an %s address\n", iptype);
803 proxy_host_address = sender_host_address;
804 sender_host_address = p;
806 if ((sp = Ustrchr(p, ' ')) == NULL)
809 debug_printf("Did not find proxy dest %s\n", iptype);
813 if(!string_is_ip_address(p,NULL))
816 debug_printf("Proxy dest arg is not an %s address\n", iptype);
819 /* Should save dest ip somewhere? */
821 if ((sp = Ustrchr(p, ' ')) == NULL)
823 DEBUG(D_receive) debug_printf("Did not find proxied src port\n");
827 tmp_port = strtol(CCS p,&endc,10);
828 if (*endc || tmp_port == 0)
831 debug_printf("Proxied src port '%s' not an integer\n", p);
834 proxy_host_port = sender_host_port;
835 sender_host_port = tmp_port;
837 if ((sp = Ustrchr(p, '\0')) == NULL)
839 DEBUG(D_receive) debug_printf("Did not find proxy dest port\n");
842 tmp_port = strtol(CCS p,&endc,10);
843 if (*endc || tmp_port == 0)
846 debug_printf("Proxy dest port '%s' not an integer\n", p);
849 /* Should save dest port somewhere? */
850 /* Already checked for /r /n above. Good V1 header received. */
856 DEBUG(D_receive) debug_printf("Wrong proxy protocol specified\n");
861 restore_socket_timeout(fd, get_ok, tvtmp, vslen);
862 /* Don't flush any potential buffer contents. Any input should cause a
863 synchronization failure or we just don't want to speak SMTP to them */
867 restore_socket_timeout(fd, get_ok, tvtmp, vslen);
870 debug_printf("Valid %s sender from Proxy Protocol header\n",
872 return proxy_session;
876 /*************************************************
877 * Read one command line *
878 *************************************************/
880 /* Strictly, SMTP commands coming over the net are supposed to end with CRLF.
881 There are sites that don't do this, and in any case internal SMTP probably
882 should check only for LF. Consequently, we check here for LF only. The line
883 ends up with [CR]LF removed from its end. If we get an overlong line, treat as
884 an unknown command. The command is read into the global smtp_cmd_buffer so that
885 it is available via $smtp_command.
887 The character reading routine sets up a timeout for each block actually read
888 from the input (which may contain more than one command). We set up a special
889 signal handler that closes down the session on a timeout. Control does not
893 check_sync if TRUE, check synchronization rules if global option is TRUE
895 Returns: a code identifying the command (enumerated above)
899 smtp_read_command(BOOL check_sync)
904 BOOL hadnull = FALSE;
906 os_non_restarting_signal(SIGALRM, command_timeout_handler);
908 while ((c = (receive_getc)()) != '\n' && c != EOF)
910 if (ptr >= smtp_cmd_buffer_size)
912 os_non_restarting_signal(SIGALRM, sigalrm_handler);
920 smtp_cmd_buffer[ptr++] = c;
923 receive_linecount++; /* For BSMTP errors */
924 os_non_restarting_signal(SIGALRM, sigalrm_handler);
926 /* If hit end of file, return pseudo EOF command. Whether we have a
927 part-line already read doesn't matter, since this is an error state. */
929 if (c == EOF) return EOF_CMD;
931 /* Remove any CR and white space at the end of the line, and terminate the
934 while (ptr > 0 && isspace(smtp_cmd_buffer[ptr-1])) ptr--;
935 smtp_cmd_buffer[ptr] = 0;
937 DEBUG(D_receive) debug_printf("SMTP<< %s\n", smtp_cmd_buffer);
939 /* NULLs are not allowed in SMTP commands */
941 if (hadnull) return BADCHAR_CMD;
943 /* Scan command list and return identity, having set the data pointer
944 to the start of the actual data characters. Check for SMTP synchronization
947 for (p = cmd_list; p < cmd_list_end; p++)
949 #ifdef EXPERIMENTAL_PROXY
950 /* Only allow QUIT command if Proxy Protocol parsing failed */
951 if (proxy_session && proxy_session_failed)
953 if (p->cmd != QUIT_CMD)
957 if (strncmpic(smtp_cmd_buffer, US p->name, p->len) == 0 &&
958 (smtp_cmd_buffer[p->len-1] == ':' || /* "mail from:" or "rcpt to:" */
959 smtp_cmd_buffer[p->len] == 0 ||
960 smtp_cmd_buffer[p->len] == ' '))
962 if (smtp_inptr < smtp_inend && /* Outstanding input */
963 p->cmd < sync_cmd_limit && /* Command should sync */
964 check_sync && /* Local flag set */
965 smtp_enforce_sync && /* Global flag set */
966 sender_host_address != NULL && /* Not local input */
967 !sender_host_notsocket) /* Really is a socket */
970 /* The variables $smtp_command and $smtp_command_argument point into the
971 unmodified input buffer. A copy of the latter is taken for actual
972 processing, so that it can be chopped up into separate parts if necessary,
973 for example, when processing a MAIL command options such as SIZE that can
974 follow the sender address. */
976 smtp_cmd_argument = smtp_cmd_buffer + p->len;
977 while (isspace(*smtp_cmd_argument)) smtp_cmd_argument++;
978 Ustrcpy(smtp_data_buffer, smtp_cmd_argument);
979 smtp_cmd_data = smtp_data_buffer;
981 /* Count non-mail commands from those hosts that are controlled in this
982 way. The default is all hosts. We don't waste effort checking the list
983 until we get a non-mail command, but then cache the result to save checking
984 again. If there's a DEFER while checking the host, assume it's in the list.
986 Note that one instance of RSET, EHLO/HELO, and STARTTLS is allowed at the
987 start of each incoming message by fiddling with the value in the table. */
991 if (count_nonmail == TRUE_UNSET) count_nonmail =
992 verify_check_host(&smtp_accept_max_nonmail_hosts) != FAIL;
993 if (count_nonmail && ++nonmail_command_count > smtp_accept_max_nonmail)
994 return TOO_MANY_NONMAIL_CMD;
997 /* If there is data for a command that does not expect it, generate the
1000 return (p->has_arg || *smtp_cmd_data == 0)? p->cmd : BADARG_CMD;
1004 #ifdef EXPERIMENTAL_PROXY
1005 /* Only allow QUIT command if Proxy Protocol parsing failed */
1006 if (proxy_session && proxy_session_failed)
1007 return PROXY_FAIL_IGNORE_CMD;
1010 /* Enforce synchronization for unknown commands */
1012 if (smtp_inptr < smtp_inend && /* Outstanding input */
1013 check_sync && /* Local flag set */
1014 smtp_enforce_sync && /* Global flag set */
1015 sender_host_address != NULL && /* Not local input */
1016 !sender_host_notsocket) /* Really is a socket */
1024 /*************************************************
1025 * Recheck synchronization *
1026 *************************************************/
1028 /* Synchronization checks can never be perfect because a packet may be on its
1029 way but not arrived when the check is done. Such checks can in any case only be
1030 done when TLS is not in use. Normally, the checks happen when commands are
1031 read: Exim ensures that there is no more input in the input buffer. In normal
1032 cases, the response to the command will be fast, and there is no further check.
1034 However, for some commands an ACL is run, and that can include delays. In those
1035 cases, it is useful to do another check on the input just before sending the
1036 response. This also applies at the start of a connection. This function does
1037 that check by means of the select() function, as long as the facility is not
1038 disabled or inappropriate. A failure of select() is ignored.
1040 When there is unwanted input, we read it so that it appears in the log of the
1044 Returns: TRUE if all is well; FALSE if there is input pending
1052 struct timeval tzero;
1054 if (!smtp_enforce_sync || sender_host_address == NULL ||
1055 sender_host_notsocket || tls_in.active >= 0)
1058 fd = fileno(smtp_in);
1063 rc = select(fd + 1, (SELECT_ARG2_TYPE *)&fds, NULL, NULL, &tzero);
1065 if (rc <= 0) return TRUE; /* Not ready to read */
1067 if (rc < 0) return TRUE; /* End of file or error */
1070 rc = smtp_inend - smtp_inptr;
1071 if (rc > 150) rc = 150;
1078 /*************************************************
1079 * Forced closedown of call *
1080 *************************************************/
1082 /* This function is called from log.c when Exim is dying because of a serious
1083 disaster, and also from some other places. If an incoming non-batched SMTP
1084 channel is open, it swallows the rest of the incoming message if in the DATA
1085 phase, sends the reply string, and gives an error to all subsequent commands
1086 except QUIT. The existence of an SMTP call is detected by the non-NULLness of
1090 message SMTP reply string to send, excluding the code
1096 smtp_closedown(uschar *message)
1098 if (smtp_in == NULL || smtp_batched_input) return;
1099 receive_swallow_smtp();
1100 smtp_printf("421 %s\r\n", message);
1104 switch(smtp_read_command(FALSE))
1110 smtp_printf("221 %s closing connection\r\n", smtp_active_hostname);
1115 smtp_printf("250 Reset OK\r\n");
1119 smtp_printf("421 %s\r\n", message);
1128 /*************************************************
1129 * Set up connection info for logging *
1130 *************************************************/
1132 /* This function is called when logging information about an SMTP connection.
1133 It sets up appropriate source information, depending on the type of connection.
1134 If sender_fullhost is NULL, we are at a very early stage of the connection;
1135 just use the IP address.
1138 Returns: a string describing the connection
1142 smtp_get_connection_info(void)
1144 uschar *hostname = (sender_fullhost == NULL)?
1145 sender_host_address : sender_fullhost;
1148 return string_sprintf("SMTP connection from %s", hostname);
1150 if (sender_host_unknown || sender_host_notsocket)
1151 return string_sprintf("SMTP connection from %s", sender_ident);
1154 return string_sprintf("SMTP connection from %s (via inetd)", hostname);
1156 if ((log_extra_selector & LX_incoming_interface) != 0 &&
1157 interface_address != NULL)
1158 return string_sprintf("SMTP connection from %s I=[%s]:%d", hostname,
1159 interface_address, interface_port);
1161 return string_sprintf("SMTP connection from %s", hostname);
1166 /*************************************************
1167 * Log lack of MAIL if so configured *
1168 *************************************************/
1170 /* This function is called when an SMTP session ends. If the log selector
1171 smtp_no_mail is set, write a log line giving some details of what has happened
1172 in the SMTP session.
1179 smtp_log_no_mail(void)
1184 if (smtp_mailcmd_count > 0 || (log_extra_selector & LX_smtp_no_mail) == 0)
1190 if (sender_host_authenticated != NULL)
1192 s = string_append(s, &size, &ptr, 2, US" A=", sender_host_authenticated);
1193 if (authenticated_id != NULL)
1194 s = string_append(s, &size, &ptr, 2, US":", authenticated_id);
1198 if ((log_extra_selector & LX_tls_cipher) != 0 && tls_in.cipher != NULL)
1199 s = string_append(s, &size, &ptr, 2, US" X=", tls_in.cipher);
1200 if ((log_extra_selector & LX_tls_certificate_verified) != 0 &&
1201 tls_in.cipher != NULL)
1202 s = string_append(s, &size, &ptr, 2, US" CV=",
1203 tls_in.certificate_verified? "yes":"no");
1204 if ((log_extra_selector & LX_tls_peerdn) != 0 && tls_in.peerdn != NULL)
1205 s = string_append(s, &size, &ptr, 3, US" DN=\"",
1206 string_printing(tls_in.peerdn), US"\"");
1207 if ((log_extra_selector & LX_tls_sni) != 0 && tls_in.sni != NULL)
1208 s = string_append(s, &size, &ptr, 3, US" SNI=\"",
1209 string_printing(tls_in.sni), US"\"");
1212 sep = (smtp_connection_had[SMTP_HBUFF_SIZE-1] != SCH_NONE)?
1213 US" C=..." : US" C=";
1214 for (i = smtp_ch_index; i < SMTP_HBUFF_SIZE; i++)
1216 if (smtp_connection_had[i] != SCH_NONE)
1218 s = string_append(s, &size, &ptr, 2, sep,
1219 smtp_names[smtp_connection_had[i]]);
1224 for (i = 0; i < smtp_ch_index; i++)
1226 s = string_append(s, &size, &ptr, 2, sep, smtp_names[smtp_connection_had[i]]);
1230 if (s != NULL) s[ptr] = 0; else s = US"";
1231 log_write(0, LOG_MAIN, "no MAIL in SMTP connection from %s D=%s%s",
1232 host_and_ident(FALSE),
1233 readconf_printtime(time(NULL) - smtp_connection_start), s);
1238 /*************************************************
1239 * Check HELO line and set sender_helo_name *
1240 *************************************************/
1242 /* Check the format of a HELO line. The data for HELO/EHLO is supposed to be
1243 the domain name of the sending host, or an ip literal in square brackets. The
1244 arrgument is placed in sender_helo_name, which is in malloc store, because it
1245 must persist over multiple incoming messages. If helo_accept_junk is set, this
1246 host is permitted to send any old junk (needed for some broken hosts).
1247 Otherwise, helo_allow_chars can be used for rogue characters in general
1248 (typically people want to let in underscores).
1251 s the data portion of the line (already past any white space)
1253 Returns: TRUE or FALSE
1257 check_helo(uschar *s)
1260 uschar *end = s + Ustrlen(s);
1261 BOOL yield = helo_accept_junk;
1263 /* Discard any previous helo name */
1265 if (sender_helo_name != NULL)
1267 store_free(sender_helo_name);
1268 sender_helo_name = NULL;
1271 /* Skip tests if junk is permitted. */
1275 /* Allow the new standard form for IPv6 address literals, namely,
1276 [IPv6:....], and because someone is bound to use it, allow an equivalent
1277 IPv4 form. Allow plain addresses as well. */
1284 if (strncmpic(s, US"[IPv6:", 6) == 0)
1285 yield = (string_is_ip_address(s+6, NULL) == 6);
1286 else if (strncmpic(s, US"[IPv4:", 6) == 0)
1287 yield = (string_is_ip_address(s+6, NULL) == 4);
1289 yield = (string_is_ip_address(s+1, NULL) != 0);
1294 /* Non-literals must be alpha, dot, hyphen, plus any non-valid chars
1295 that have been configured (usually underscore - sigh). */
1302 if (!isalnum(*s) && *s != '.' && *s != '-' &&
1303 Ustrchr(helo_allow_chars, *s) == NULL)
1313 /* Save argument if OK */
1315 if (yield) sender_helo_name = string_copy_malloc(start);
1323 /*************************************************
1324 * Extract SMTP command option *
1325 *************************************************/
1327 /* This function picks the next option setting off the end of smtp_cmd_data. It
1328 is called for MAIL FROM and RCPT TO commands, to pick off the optional ESMTP
1329 things that can appear there.
1332 name point this at the name
1333 value point this at the data string
1335 Returns: TRUE if found an option
1339 extract_option(uschar **name, uschar **value)
1342 uschar *v = smtp_cmd_data + Ustrlen(smtp_cmd_data) - 1;
1343 while (isspace(*v)) v--;
1345 while (v > smtp_cmd_data && *v != '=' && !isspace(*v)) v--;
1350 while(isalpha(n[-1])) n--;
1351 /* RFC says SP, but TAB seen in wild and other major MTAs accept it */
1352 if (!isspace(n[-1])) return FALSE;
1358 if (v == smtp_cmd_data) return FALSE;
1370 /*************************************************
1371 * Reset for new message *
1372 *************************************************/
1374 /* This function is called whenever the SMTP session is reset from
1375 within either of the setup functions.
1377 Argument: the stacking pool storage reset point
1382 smtp_reset(void *reset_point)
1384 store_reset(reset_point);
1385 recipients_list = NULL;
1386 rcpt_count = rcpt_defer_count = rcpt_fail_count =
1387 raw_recipients_count = recipients_count = recipients_list_max = 0;
1388 cancel_cutthrough_connection("smtp reset");
1389 message_linecount = 0;
1391 acl_added_headers = NULL;
1392 acl_removed_headers = NULL;
1393 queue_only_policy = FALSE;
1394 rcpt_smtp_response = NULL;
1395 rcpt_smtp_response_same = TRUE;
1396 rcpt_in_progress = FALSE;
1397 deliver_freeze = FALSE; /* Can be set by ACL */
1398 freeze_tell = freeze_tell_config; /* Can be set by ACL */
1399 fake_response = OK; /* Can be set by ACL */
1400 #ifdef WITH_CONTENT_SCAN
1401 no_mbox_unspool = FALSE; /* Can be set by ACL */
1403 submission_mode = FALSE; /* Can be set by ACL */
1404 suppress_local_fixups = suppress_local_fixups_default; /* Can be set by ACL */
1405 active_local_from_check = local_from_check; /* Can be set by ACL */
1406 active_local_sender_retain = local_sender_retain; /* Can be set by ACL */
1407 sender_address = NULL;
1408 submission_name = NULL; /* Can be set by ACL */
1409 raw_sender = NULL; /* After SMTP rewrite, before qualifying */
1410 sender_address_unrewritten = NULL; /* Set only after verify rewrite */
1411 sender_verified_list = NULL; /* No senders verified */
1412 memset(sender_address_cache, 0, sizeof(sender_address_cache));
1413 memset(sender_domain_cache, 0, sizeof(sender_domain_cache));
1414 authenticated_sender = NULL;
1415 #ifdef EXPERIMENTAL_BRIGHTMAIL
1417 bmi_verdicts = NULL;
1419 #ifndef DISABLE_DKIM
1420 dkim_signers = NULL;
1421 dkim_disable_verify = FALSE;
1422 dkim_collect_input = FALSE;
1424 #ifdef EXPERIMENTAL_SPF
1425 spf_header_comment = NULL;
1426 spf_received = NULL;
1428 spf_smtp_comment = NULL;
1430 body_linecount = body_zerocount = 0;
1432 sender_rate = sender_rate_limit = sender_rate_period = NULL;
1433 ratelimiters_mail = NULL; /* Updated by ratelimit ACL condition */
1434 /* Note that ratelimiters_conn persists across resets. */
1436 /* Reset message ACL variables */
1440 /* The message body variables use malloc store. They may be set if this is
1441 not the first message in an SMTP session and the previous message caused them
1442 to be referenced in an ACL. */
1444 if (message_body != NULL)
1446 store_free(message_body);
1447 message_body = NULL;
1450 if (message_body_end != NULL)
1452 store_free(message_body_end);
1453 message_body_end = NULL;
1456 /* Warning log messages are also saved in malloc store. They are saved to avoid
1457 repetition in the same message, but it seems right to repeat them for different
1460 while (acl_warn_logged != NULL)
1462 string_item *this = acl_warn_logged;
1463 acl_warn_logged = acl_warn_logged->next;
1472 /*************************************************
1473 * Initialize for incoming batched SMTP message *
1474 *************************************************/
1476 /* This function is called from smtp_setup_msg() in the case when
1477 smtp_batched_input is true. This happens when -bS is used to pass a whole batch
1478 of messages in one file with SMTP commands between them. All errors must be
1479 reported by sending a message, and only MAIL FROM, RCPT TO, and DATA are
1480 relevant. After an error on a sender, or an invalid recipient, the remainder
1481 of the message is skipped. The value of received_protocol is already set.
1484 Returns: > 0 message successfully started (reached DATA)
1485 = 0 QUIT read or end of file reached
1486 < 0 should not occur
1490 smtp_setup_batch_msg(void)
1493 void *reset_point = store_get(0);
1495 /* Save the line count at the start of each transaction - single commands
1496 like HELO and RSET count as whole transactions. */
1498 bsmtp_transaction_linecount = receive_linecount;
1500 if ((receive_feof)()) return 0; /* Treat EOF as QUIT */
1502 smtp_reset(reset_point); /* Reset for start of message */
1504 /* Deal with SMTP commands. This loop is exited by setting done to a POSITIVE
1505 value. The values are 2 larger than the required yield of the function. */
1510 uschar *recipient = NULL;
1511 int start, end, sender_domain, recipient_domain;
1513 switch(smtp_read_command(FALSE))
1515 /* The HELO/EHLO commands set sender_address_helo if they have
1516 valid data; otherwise they are ignored, except that they do
1517 a reset of the state. */
1522 check_helo(smtp_cmd_data);
1526 smtp_reset(reset_point);
1527 bsmtp_transaction_linecount = receive_linecount;
1531 /* The MAIL FROM command requires an address as an operand. All we
1532 do here is to parse it for syntactic correctness. The form "<>" is
1533 a special case which converts into an empty string. The start/end
1534 pointers in the original are not used further for this address, as
1535 it is the canonical extracted address which is all that is kept. */
1538 if (sender_address != NULL)
1539 /* The function moan_smtp_batch() does not return. */
1540 moan_smtp_batch(smtp_cmd_buffer, "503 Sender already given");
1542 if (smtp_cmd_data[0] == 0)
1543 /* The function moan_smtp_batch() does not return. */
1544 moan_smtp_batch(smtp_cmd_buffer, "501 MAIL FROM must have an address operand");
1546 /* Reset to start of message */
1548 smtp_reset(reset_point);
1550 /* Apply SMTP rewrite */
1552 raw_sender = ((rewrite_existflags & rewrite_smtp) != 0)?
1553 rewrite_one(smtp_cmd_data, rewrite_smtp|rewrite_smtp_sender, NULL, FALSE,
1554 US"", global_rewrite_rules) : smtp_cmd_data;
1556 /* Extract the address; the TRUE flag allows <> as valid */
1559 parse_extract_address(raw_sender, &errmess, &start, &end, &sender_domain,
1562 if (raw_sender == NULL)
1563 /* The function moan_smtp_batch() does not return. */
1564 moan_smtp_batch(smtp_cmd_buffer, "501 %s", errmess);
1566 sender_address = string_copy(raw_sender);
1568 /* Qualify unqualified sender addresses if permitted to do so. */
1570 if (sender_domain == 0 && sender_address[0] != 0 && sender_address[0] != '@')
1572 if (allow_unqualified_sender)
1574 sender_address = rewrite_address_qualify(sender_address, FALSE);
1575 DEBUG(D_receive) debug_printf("unqualified address %s accepted "
1576 "and rewritten\n", raw_sender);
1578 /* The function moan_smtp_batch() does not return. */
1579 else moan_smtp_batch(smtp_cmd_buffer, "501 sender address must contain "
1585 /* The RCPT TO command requires an address as an operand. All we do
1586 here is to parse it for syntactic correctness. There may be any number
1587 of RCPT TO commands, specifying multiple senders. We build them all into
1588 a data structure that is in argc/argv format. The start/end values
1589 given by parse_extract_address are not used, as we keep only the
1590 extracted address. */
1593 if (sender_address == NULL)
1594 /* The function moan_smtp_batch() does not return. */
1595 moan_smtp_batch(smtp_cmd_buffer, "503 No sender yet given");
1597 if (smtp_cmd_data[0] == 0)
1598 /* The function moan_smtp_batch() does not return. */
1599 moan_smtp_batch(smtp_cmd_buffer, "501 RCPT TO must have an address operand");
1601 /* Check maximum number allowed */
1603 if (recipients_max > 0 && recipients_count + 1 > recipients_max)
1604 /* The function moan_smtp_batch() does not return. */
1605 moan_smtp_batch(smtp_cmd_buffer, "%s too many recipients",
1606 recipients_max_reject? "552": "452");
1608 /* Apply SMTP rewrite, then extract address. Don't allow "<>" as a
1609 recipient address */
1611 recipient = ((rewrite_existflags & rewrite_smtp) != 0)?
1612 rewrite_one(smtp_cmd_data, rewrite_smtp, NULL, FALSE, US"",
1613 global_rewrite_rules) : smtp_cmd_data;
1615 /* rfc821_domains = TRUE; << no longer needed */
1616 recipient = parse_extract_address(recipient, &errmess, &start, &end,
1617 &recipient_domain, FALSE);
1618 /* rfc821_domains = FALSE; << no longer needed */
1620 if (recipient == NULL)
1621 /* The function moan_smtp_batch() does not return. */
1622 moan_smtp_batch(smtp_cmd_buffer, "501 %s", errmess);
1624 /* If the recipient address is unqualified, qualify it if permitted. Then
1625 add it to the list of recipients. */
1627 if (recipient_domain == 0)
1629 if (allow_unqualified_recipient)
1631 DEBUG(D_receive) debug_printf("unqualified address %s accepted\n",
1633 recipient = rewrite_address_qualify(recipient, TRUE);
1635 /* The function moan_smtp_batch() does not return. */
1636 else moan_smtp_batch(smtp_cmd_buffer, "501 recipient address must contain "
1639 receive_add_recipient(recipient, -1);
1643 /* The DATA command is legal only if it follows successful MAIL FROM
1644 and RCPT TO commands. This function is complete when a valid DATA
1645 command is encountered. */
1648 if (sender_address == NULL || recipients_count <= 0)
1650 /* The function moan_smtp_batch() does not return. */
1651 if (sender_address == NULL)
1652 moan_smtp_batch(smtp_cmd_buffer,
1653 "503 MAIL FROM:<sender> command must precede DATA");
1655 moan_smtp_batch(smtp_cmd_buffer,
1656 "503 RCPT TO:<recipient> must precede DATA");
1660 done = 3; /* DATA successfully achieved */
1661 message_ended = END_NOTENDED; /* Indicate in middle of message */
1666 /* The VRFY, EXPN, HELP, ETRN, and NOOP commands are ignored. */
1673 bsmtp_transaction_linecount = receive_linecount;
1684 /* The function moan_smtp_batch() does not return. */
1685 moan_smtp_batch(smtp_cmd_buffer, "501 Unexpected argument data");
1690 /* The function moan_smtp_batch() does not return. */
1691 moan_smtp_batch(smtp_cmd_buffer, "501 Unexpected NULL in SMTP command");
1696 /* The function moan_smtp_batch() does not return. */
1697 moan_smtp_batch(smtp_cmd_buffer, "500 Command unrecognized");
1702 return done - 2; /* Convert yield values */
1708 /*************************************************
1709 * Start an SMTP session *
1710 *************************************************/
1712 /* This function is called at the start of an SMTP session. Thereafter,
1713 smtp_setup_msg() is called to initiate each separate message. This
1714 function does host-specific testing, and outputs the banner line.
1717 Returns: FALSE if the session can not continue; something has
1718 gone wrong, or the connection to the host is blocked
1722 smtp_start_session(void)
1726 uschar *user_msg, *log_msg;
1730 smtp_connection_start = time(NULL);
1731 for (smtp_ch_index = 0; smtp_ch_index < SMTP_HBUFF_SIZE; smtp_ch_index++)
1732 smtp_connection_had[smtp_ch_index] = SCH_NONE;
1735 /* Default values for certain variables */
1737 helo_seen = esmtp = helo_accept_junk = FALSE;
1738 smtp_mailcmd_count = 0;
1739 count_nonmail = TRUE_UNSET;
1740 synprot_error_count = unknown_command_count = nonmail_command_count = 0;
1741 smtp_delay_mail = smtp_rlm_base;
1742 auth_advertised = FALSE;
1743 pipelining_advertised = FALSE;
1744 pipelining_enable = TRUE;
1745 sync_cmd_limit = NON_SYNC_CMD_NON_PIPELINING;
1746 smtp_exit_function_called = FALSE; /* For avoiding loop in not-quit exit */
1748 memset(sender_host_cache, 0, sizeof(sender_host_cache));
1750 /* If receiving by -bs from a trusted user, or testing with -bh, we allow
1751 authentication settings from -oMaa to remain in force. */
1753 if (!host_checking && !sender_host_notsocket) sender_host_authenticated = NULL;
1754 authenticated_by = NULL;
1757 tls_in.cipher = tls_in.peerdn = NULL;
1758 tls_advertised = FALSE;
1761 /* Reset ACL connection variables */
1765 /* Allow for trailing 0 in the command and data buffers. */
1767 smtp_cmd_buffer = (uschar *)malloc(2*smtp_cmd_buffer_size + 2);
1768 if (smtp_cmd_buffer == NULL)
1769 log_write(0, LOG_MAIN|LOG_PANIC_DIE,
1770 "malloc() failed for SMTP command buffer");
1771 smtp_cmd_buffer[0] = 0;
1772 smtp_data_buffer = smtp_cmd_buffer + smtp_cmd_buffer_size + 1;
1774 /* For batched input, the protocol setting can be overridden from the
1775 command line by a trusted caller. */
1777 if (smtp_batched_input)
1779 if (received_protocol == NULL) received_protocol = US"local-bsmtp";
1782 /* For non-batched SMTP input, the protocol setting is forced here. It will be
1783 reset later if any of EHLO/AUTH/STARTTLS are received. */
1787 protocols[pnormal] + ((sender_host_address != NULL)? pnlocal : 0);
1789 /* Set up the buffer for inputting using direct read() calls, and arrange to
1790 call the local functions instead of the standard C ones. */
1792 smtp_inbuffer = (uschar *)malloc(in_buffer_size);
1793 if (smtp_inbuffer == NULL)
1794 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "malloc() failed for SMTP input buffer");
1795 receive_getc = smtp_getc;
1796 receive_ungetc = smtp_ungetc;
1797 receive_feof = smtp_feof;
1798 receive_ferror = smtp_ferror;
1799 receive_smtp_buffered = smtp_buffered;
1800 smtp_inptr = smtp_inend = smtp_inbuffer;
1801 smtp_had_eof = smtp_had_error = 0;
1803 /* Set up the message size limit; this may be host-specific */
1805 thismessage_size_limit = expand_string_integer(message_size_limit, TRUE);
1806 if (expand_string_message != NULL)
1808 if (thismessage_size_limit == -1)
1809 log_write(0, LOG_MAIN|LOG_PANIC, "unable to expand message_size_limit: "
1810 "%s", expand_string_message);
1812 log_write(0, LOG_MAIN|LOG_PANIC, "invalid message_size_limit: "
1813 "%s", expand_string_message);
1814 smtp_closedown(US"Temporary local problem - please try later");
1818 /* When a message is input locally via the -bs or -bS options, sender_host_
1819 unknown is set unless -oMa was used to force an IP address, in which case it
1820 is checked like a real remote connection. When -bs is used from inetd, this
1821 flag is not set, causing the sending host to be checked. The code that deals
1822 with IP source routing (if configured) is never required for -bs or -bS and
1823 the flag sender_host_notsocket is used to suppress it.
1825 If smtp_accept_max and smtp_accept_reserve are set, keep some connections in
1826 reserve for certain hosts and/or networks. */
1828 if (!sender_host_unknown)
1831 BOOL reserved_host = FALSE;
1833 /* Look up IP options (source routing info) on the socket if this is not an
1834 -oMa "host", and if any are found, log them and drop the connection.
1836 Linux (and others now, see below) is different to everyone else, so there
1837 has to be some conditional compilation here. Versions of Linux before 2.1.15
1838 used a structure whose name was "options". Somebody finally realized that
1839 this name was silly, and it got changed to "ip_options". I use the
1840 newer name here, but there is a fudge in the script that sets up os.h
1841 to define a macro in older Linux systems.
1843 Sigh. Linux is a fast-moving target. Another generation of Linux uses
1844 glibc 2, which has chosen ip_opts for the structure name. This is now
1845 really a glibc thing rather than a Linux thing, so the condition name
1846 has been changed to reflect this. It is relevant also to GNU/Hurd.
1848 Mac OS 10.x (Darwin) is like the later glibc versions, but without the
1849 setting of the __GLIBC__ macro, so we can't detect it automatically. There's
1850 a special macro defined in the os.h file.
1852 Some DGUX versions on older hardware appear not to support IP options at
1853 all, so there is now a general macro which can be set to cut out this
1856 How to do this properly in IPv6 is not yet known. */
1858 #if !HAVE_IPV6 && !defined(NO_IP_OPTIONS)
1860 #ifdef GLIBC_IP_OPTIONS
1861 #if (!defined __GLIBC__) || (__GLIBC__ < 2)
1866 #elif defined DARWIN_IP_OPTIONS
1872 if (!host_checking && !sender_host_notsocket)
1875 EXIM_SOCKLEN_T optlen = sizeof(struct ip_options) + MAX_IPOPTLEN;
1876 struct ip_options *ipopt = store_get(optlen);
1878 struct ip_opts ipoptblock;
1879 struct ip_opts *ipopt = &ipoptblock;
1880 EXIM_SOCKLEN_T optlen = sizeof(ipoptblock);
1882 struct ipoption ipoptblock;
1883 struct ipoption *ipopt = &ipoptblock;
1884 EXIM_SOCKLEN_T optlen = sizeof(ipoptblock);
1887 /* Occasional genuine failures of getsockopt() have been seen - for
1888 example, "reset by peer". Therefore, just log and give up on this
1889 call, unless the error is ENOPROTOOPT. This error is given by systems
1890 that have the interfaces but not the mechanism - e.g. GNU/Hurd at the time
1891 of writing. So for that error, carry on - we just can't do an IP options
1894 DEBUG(D_receive) debug_printf("checking for IP options\n");
1896 if (getsockopt(fileno(smtp_out), IPPROTO_IP, IP_OPTIONS, (uschar *)(ipopt),
1899 if (errno != ENOPROTOOPT)
1901 log_write(0, LOG_MAIN, "getsockopt() failed from %s: %s",
1902 host_and_ident(FALSE), strerror(errno));
1903 smtp_printf("451 SMTP service not available\r\n");
1908 /* Deal with any IP options that are set. On the systems I have looked at,
1909 the value of MAX_IPOPTLEN has been 40, meaning that there should never be
1910 more logging data than will fit in big_buffer. Nevertheless, after somebody
1911 questioned this code, I've added in some paranoid checking. */
1913 else if (optlen > 0)
1915 uschar *p = big_buffer;
1916 uschar *pend = big_buffer + big_buffer_size;
1917 uschar *opt, *adptr;
1919 struct in_addr addr;
1922 uschar *optstart = (uschar *)(ipopt->__data);
1924 uschar *optstart = (uschar *)(ipopt->ip_opts);
1926 uschar *optstart = (uschar *)(ipopt->ipopt_list);
1929 DEBUG(D_receive) debug_printf("IP options exist\n");
1931 Ustrcpy(p, "IP options on incoming call:");
1934 for (opt = optstart; opt != NULL &&
1935 opt < (uschar *)(ipopt) + optlen;)
1949 if (!string_format(p, pend-p, " %s [@%s",
1950 (*opt == IPOPT_SSRR)? "SSRR" : "LSRR",
1952 inet_ntoa(*((struct in_addr *)(&(ipopt->faddr))))))
1954 inet_ntoa(ipopt->ip_dst)))
1956 inet_ntoa(ipopt->ipopt_dst)))
1964 optcount = (opt[1] - 3) / sizeof(struct in_addr);
1966 while (optcount-- > 0)
1968 memcpy(&addr, adptr, sizeof(addr));
1969 if (!string_format(p, pend - p - 1, "%s%s",
1970 (optcount == 0)? ":" : "@", inet_ntoa(addr)))
1976 adptr += sizeof(struct in_addr);
1985 if (pend - p < 4 + 3*opt[1]) { opt = NULL; break; }
1988 for (i = 0; i < opt[1]; i++)
1990 sprintf(CS p, "%2.2x ", opt[i]);
2001 log_write(0, LOG_MAIN, "%s", big_buffer);
2003 /* Refuse any call with IP options. This is what tcpwrappers 7.5 does. */
2005 log_write(0, LOG_MAIN|LOG_REJECT,
2006 "connection from %s refused (IP options)", host_and_ident(FALSE));
2008 smtp_printf("554 SMTP service not available\r\n");
2012 /* Length of options = 0 => there are no options */
2014 else DEBUG(D_receive) debug_printf("no IP options found\n");
2016 #endif /* HAVE_IPV6 && !defined(NO_IP_OPTIONS) */
2018 /* Set keep-alive in socket options. The option is on by default. This
2019 setting is an attempt to get rid of some hanging connections that stick in
2020 read() when the remote end (usually a dialup) goes away. */
2022 if (smtp_accept_keepalive && !sender_host_notsocket)
2023 ip_keepalive(fileno(smtp_out), sender_host_address, FALSE);
2025 /* If the current host matches host_lookup, set the name by doing a
2026 reverse lookup. On failure, sender_host_name will be NULL and
2027 host_lookup_failed will be TRUE. This may or may not be serious - optional
2030 if (verify_check_host(&host_lookup) == OK)
2032 (void)host_name_lookup();
2033 host_build_sender_fullhost();
2036 /* Delay this until we have the full name, if it is looked up. */
2038 set_process_info("handling incoming connection from %s",
2039 host_and_ident(FALSE));
2041 /* Start up TLS if tls_on_connect is set. This is for supporting the legacy
2042 smtps port for use with older style SSL MTAs. */
2045 if (tls_in.on_connect && tls_server_start(tls_require_ciphers) != OK)
2049 /* Test for explicit connection rejection */
2051 if (verify_check_host(&host_reject_connection) == OK)
2053 log_write(L_connection_reject, LOG_MAIN|LOG_REJECT, "refused connection "
2054 "from %s (host_reject_connection)", host_and_ident(FALSE));
2055 smtp_printf("554 SMTP service not available\r\n");
2059 /* Test with TCP Wrappers if so configured. There is a problem in that
2060 hosts_ctl() returns 0 (deny) under a number of system failure circumstances,
2061 such as disks dying. In these cases, it is desirable to reject with a 4xx
2062 error instead of a 5xx error. There isn't a "right" way to detect such
2063 problems. The following kludge is used: errno is zeroed before calling
2064 hosts_ctl(). If the result is "reject", a 5xx error is given only if the
2065 value of errno is 0 or ENOENT (which happens if /etc/hosts.{allow,deny} does
2068 #ifdef USE_TCP_WRAPPERS
2070 tcp_wrappers_name = expand_string(tcp_wrappers_daemon_name);
2071 if (tcp_wrappers_name == NULL)
2073 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "Expansion of \"%s\" "
2074 "(tcp_wrappers_name) failed: %s", string_printing(tcp_wrappers_name),
2075 expand_string_message);
2077 if (!hosts_ctl(tcp_wrappers_name,
2078 (sender_host_name == NULL)? STRING_UNKNOWN : CS sender_host_name,
2079 (sender_host_address == NULL)? STRING_UNKNOWN : CS sender_host_address,
2080 (sender_ident == NULL)? STRING_UNKNOWN : CS sender_ident))
2082 if (errno == 0 || errno == ENOENT)
2084 HDEBUG(D_receive) debug_printf("tcp wrappers rejection\n");
2085 log_write(L_connection_reject,
2086 LOG_MAIN|LOG_REJECT, "refused connection from %s "
2087 "(tcp wrappers)", host_and_ident(FALSE));
2088 smtp_printf("554 SMTP service not available\r\n");
2092 int save_errno = errno;
2093 HDEBUG(D_receive) debug_printf("tcp wrappers rejected with unexpected "
2094 "errno value %d\n", save_errno);
2095 log_write(L_connection_reject,
2096 LOG_MAIN|LOG_REJECT, "temporarily refused connection from %s "
2097 "(tcp wrappers errno=%d)", host_and_ident(FALSE), save_errno);
2098 smtp_printf("451 Temporary local problem - please try later\r\n");
2104 /* Check for reserved slots. The value of smtp_accept_count has already been
2105 incremented to include this process. */
2107 if (smtp_accept_max > 0 &&
2108 smtp_accept_count > smtp_accept_max - smtp_accept_reserve)
2110 if ((rc = verify_check_host(&smtp_reserve_hosts)) != OK)
2112 log_write(L_connection_reject,
2113 LOG_MAIN, "temporarily refused connection from %s: not in "
2114 "reserve list: connected=%d max=%d reserve=%d%s",
2115 host_and_ident(FALSE), smtp_accept_count - 1, smtp_accept_max,
2116 smtp_accept_reserve, (rc == DEFER)? " (lookup deferred)" : "");
2117 smtp_printf("421 %s: Too many concurrent SMTP connections; "
2118 "please try again later\r\n", smtp_active_hostname);
2121 reserved_host = TRUE;
2124 /* If a load level above which only messages from reserved hosts are
2125 accepted is set, check the load. For incoming calls via the daemon, the
2126 check is done in the superior process if there are no reserved hosts, to
2127 save a fork. In all cases, the load average will already be available
2128 in a global variable at this point. */
2130 if (smtp_load_reserve >= 0 &&
2131 load_average > smtp_load_reserve &&
2133 verify_check_host(&smtp_reserve_hosts) != OK)
2135 log_write(L_connection_reject,
2136 LOG_MAIN, "temporarily refused connection from %s: not in "
2137 "reserve list and load average = %.2f", host_and_ident(FALSE),
2138 (double)load_average/1000.0);
2139 smtp_printf("421 %s: Too much load; please try again later\r\n",
2140 smtp_active_hostname);
2144 /* Determine whether unqualified senders or recipients are permitted
2145 for this host. Unfortunately, we have to do this every time, in order to
2146 set the flags so that they can be inspected when considering qualifying
2147 addresses in the headers. For a site that permits no qualification, this
2148 won't take long, however. */
2150 allow_unqualified_sender =
2151 verify_check_host(&sender_unqualified_hosts) == OK;
2153 allow_unqualified_recipient =
2154 verify_check_host(&recipient_unqualified_hosts) == OK;
2156 /* Determine whether HELO/EHLO is required for this host. The requirement
2157 can be hard or soft. */
2159 helo_required = verify_check_host(&helo_verify_hosts) == OK;
2161 helo_verify = verify_check_host(&helo_try_verify_hosts) == OK;
2163 /* Determine whether this hosts is permitted to send syntactic junk
2164 after a HELO or EHLO command. */
2166 helo_accept_junk = verify_check_host(&helo_accept_junk_hosts) == OK;
2169 /* For batch SMTP input we are now done. */
2171 if (smtp_batched_input) return TRUE;
2173 #ifdef EXPERIMENTAL_PROXY
2174 /* If valid Proxy Protocol source is connecting, set up session.
2175 * Failure will not allow any SMTP function other than QUIT. */
2176 proxy_session = FALSE;
2177 proxy_session_failed = FALSE;
2178 if (check_proxy_protocol_host())
2180 if (setup_proxy_protocol_host() == FALSE)
2182 proxy_session_failed = TRUE;
2184 debug_printf("Failure to extract proxied host, only QUIT allowed\n");
2188 sender_host_name = NULL;
2189 (void)host_name_lookup();
2190 host_build_sender_fullhost();
2195 /* Run the ACL if it exists */
2198 if (acl_smtp_connect != NULL)
2201 rc = acl_check(ACL_WHERE_CONNECT, NULL, acl_smtp_connect, &user_msg,
2205 (void)smtp_handle_acl_fail(ACL_WHERE_CONNECT, rc, user_msg, log_msg);
2210 /* Output the initial message for a two-way SMTP connection. It may contain
2211 newlines, which then cause a multi-line response to be given. */
2213 code = US"220"; /* Default status code */
2214 esc = US""; /* Default extended status code */
2215 esclen = 0; /* Length of esc */
2217 if (user_msg == NULL)
2219 s = expand_string(smtp_banner);
2221 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "Expansion of \"%s\" (smtp_banner) "
2222 "failed: %s", smtp_banner, expand_string_message);
2228 smtp_message_code(&code, &codelen, &s, NULL);
2232 esclen = codelen - 4;
2236 /* Remove any terminating newlines; might as well remove trailing space too */
2239 while (p > s && isspace(p[-1])) p--;
2242 /* It seems that CC:Mail is braindead, and assumes that the greeting message
2243 is all contained in a single IP packet. The original code wrote out the
2244 greeting using several calls to fprint/fputc, and on busy servers this could
2245 cause it to be split over more than one packet - which caused CC:Mail to fall
2246 over when it got the second part of the greeting after sending its first
2247 command. Sigh. To try to avoid this, build the complete greeting message
2248 first, and output it in one fell swoop. This gives a better chance of it
2249 ending up as a single packet. */
2251 ss = store_get(size);
2255 do /* At least once, in case we have an empty string */
2258 uschar *linebreak = Ustrchr(p, '\n');
2259 ss = string_cat(ss, &size, &ptr, code, 3);
2260 if (linebreak == NULL)
2263 ss = string_cat(ss, &size, &ptr, US" ", 1);
2267 len = linebreak - p;
2268 ss = string_cat(ss, &size, &ptr, US"-", 1);
2270 ss = string_cat(ss, &size, &ptr, esc, esclen);
2271 ss = string_cat(ss, &size, &ptr, p, len);
2272 ss = string_cat(ss, &size, &ptr, US"\r\n", 2);
2274 if (linebreak != NULL) p++;
2278 ss[ptr] = 0; /* string_cat leaves room for this */
2280 /* Before we write the banner, check that there is no input pending, unless
2281 this synchronisation check is disabled. */
2285 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP protocol "
2286 "synchronization error (input sent without waiting for greeting): "
2287 "rejected connection from %s input=\"%s\"", host_and_ident(TRUE),
2288 string_printing(smtp_inptr));
2289 smtp_printf("554 SMTP synchronization error\r\n");
2293 /* Now output the banner */
2295 smtp_printf("%s", ss);
2303 /*************************************************
2304 * Handle SMTP syntax and protocol errors *
2305 *************************************************/
2307 /* Write to the log for SMTP syntax errors in incoming commands, if configured
2308 to do so. Then transmit the error response. The return value depends on the
2309 number of syntax and protocol errors in this SMTP session.
2312 type error type, given as a log flag bit
2313 code response code; <= 0 means don't send a response
2314 data data to reflect in the response (can be NULL)
2315 errmess the error message
2317 Returns: -1 limit of syntax/protocol errors NOT exceeded
2318 +1 limit of syntax/protocol errors IS exceeded
2320 These values fit in with the values of the "done" variable in the main
2321 processing loop in smtp_setup_msg(). */
2324 synprot_error(int type, int code, uschar *data, uschar *errmess)
2328 log_write(type, LOG_MAIN, "SMTP %s error in \"%s\" %s %s",
2329 (type == L_smtp_syntax_error)? "syntax" : "protocol",
2330 string_printing(smtp_cmd_buffer), host_and_ident(TRUE), errmess);
2332 if (++synprot_error_count > smtp_max_synprot_errors)
2335 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
2336 "syntax or protocol errors (last command was \"%s\")",
2337 host_and_ident(FALSE), smtp_cmd_buffer);
2342 smtp_printf("%d%c%s%s%s\r\n", code, (yield == 1)? '-' : ' ',
2343 (data == NULL)? US"" : data, (data == NULL)? US"" : US": ", errmess);
2345 smtp_printf("%d Too many syntax or protocol errors\r\n", code);
2354 /*************************************************
2355 * Log incomplete transactions *
2356 *************************************************/
2358 /* This function is called after a transaction has been aborted by RSET, QUIT,
2359 connection drops or other errors. It logs the envelope information received
2360 so far in order to preserve address verification attempts.
2362 Argument: string to indicate what aborted the transaction
2367 incomplete_transaction_log(uschar *what)
2369 if (sender_address == NULL || /* No transaction in progress */
2370 (log_write_selector & L_smtp_incomplete_transaction) == 0 /* Not logging */
2373 /* Build list of recipients for logging */
2375 if (recipients_count > 0)
2378 raw_recipients = store_get(recipients_count * sizeof(uschar *));
2379 for (i = 0; i < recipients_count; i++)
2380 raw_recipients[i] = recipients_list[i].address;
2381 raw_recipients_count = recipients_count;
2384 log_write(L_smtp_incomplete_transaction, LOG_MAIN|LOG_SENDER|LOG_RECIPIENTS,
2385 "%s incomplete transaction (%s)", host_and_ident(TRUE), what);
2391 /*************************************************
2392 * Send SMTP response, possibly multiline *
2393 *************************************************/
2395 /* There are, it seems, broken clients out there that cannot handle multiline
2396 responses. If no_multiline_responses is TRUE (it can be set from an ACL), we
2397 output nothing for non-final calls, and only the first line for anything else.
2400 code SMTP code, may involve extended status codes
2401 codelen length of smtp code; if > 4 there's an ESC
2402 final FALSE if the last line isn't the final line
2403 msg message text, possibly containing newlines
2409 smtp_respond(uschar* code, int codelen, BOOL final, uschar *msg)
2414 if (!final && no_multiline_responses) return;
2419 esclen = codelen - 4;
2422 /* If this is the first output for a (non-batch) RCPT command, see if all RCPTs
2423 have had the same. Note: this code is also present in smtp_printf(). It would
2424 be tidier to have it only in one place, but when it was added, it was easier to
2425 do it that way, so as not to have to mess with the code for the RCPT command,
2426 which sometimes uses smtp_printf() and sometimes smtp_respond(). */
2428 if (rcpt_in_progress)
2430 if (rcpt_smtp_response == NULL)
2431 rcpt_smtp_response = string_copy(msg);
2432 else if (rcpt_smtp_response_same &&
2433 Ustrcmp(rcpt_smtp_response, msg) != 0)
2434 rcpt_smtp_response_same = FALSE;
2435 rcpt_in_progress = FALSE;
2438 /* Not output the message, splitting it up into multiple lines if necessary. */
2442 uschar *nl = Ustrchr(msg, '\n');
2445 smtp_printf("%.3s%c%.*s%s\r\n", code, final? ' ':'-', esclen, esc, msg);
2448 else if (nl[1] == 0 || no_multiline_responses)
2450 smtp_printf("%.3s%c%.*s%.*s\r\n", code, final? ' ':'-', esclen, esc,
2451 (int)(nl - msg), msg);
2456 smtp_printf("%.3s-%.*s%.*s\r\n", code, esclen, esc, (int)(nl - msg), msg);
2458 while (isspace(*msg)) msg++;
2466 /*************************************************
2467 * Parse user SMTP message *
2468 *************************************************/
2470 /* This function allows for user messages overriding the response code details
2471 by providing a suitable response code string at the start of the message
2472 user_msg. Check the message for starting with a response code and optionally an
2473 extended status code. If found, check that the first digit is valid, and if so,
2474 change the code pointer and length to use the replacement. An invalid code
2475 causes a panic log; in this case, if the log messages is the same as the user
2476 message, we must also adjust the value of the log message to show the code that
2477 is actually going to be used (the original one).
2479 This function is global because it is called from receive.c as well as within
2482 Note that the code length returned includes the terminating whitespace
2483 character, which is always included in the regex match.
2486 code SMTP code, may involve extended status codes
2487 codelen length of smtp code; if > 4 there's an ESC
2489 log_msg optional log message, to be adjusted with the new SMTP code
2495 smtp_message_code(uschar **code, int *codelen, uschar **msg, uschar **log_msg)
2500 if (msg == NULL || *msg == NULL) return;
2502 n = pcre_exec(regex_smtp_code, NULL, CS *msg, Ustrlen(*msg), 0,
2503 PCRE_EOPT, ovector, sizeof(ovector)/sizeof(int));
2506 if ((*msg)[0] != (*code)[0])
2508 log_write(0, LOG_MAIN|LOG_PANIC, "configured error code starts with "
2509 "incorrect digit (expected %c) in \"%s\"", (*code)[0], *msg);
2510 if (log_msg != NULL && *log_msg == *msg)
2511 *log_msg = string_sprintf("%s %s", *code, *log_msg + ovector[1]);
2516 *codelen = ovector[1]; /* Includes final space */
2518 *msg += ovector[1]; /* Chop the code off the message */
2525 /*************************************************
2526 * Handle an ACL failure *
2527 *************************************************/
2529 /* This function is called when acl_check() fails. As well as calls from within
2530 this module, it is called from receive.c for an ACL after DATA. It sorts out
2531 logging the incident, and sets up the error response. A message containing
2532 newlines is turned into a multiline SMTP response, but for logging, only the
2535 There's a table of default permanent failure response codes to use in
2536 globals.c, along with the table of names. VFRY is special. Despite RFC1123 it
2537 defaults disabled in Exim. However, discussion in connection with RFC 821bis
2538 (aka RFC 2821) has concluded that the response should be 252 in the disabled
2539 state, because there are broken clients that try VRFY before RCPT. A 5xx
2540 response should be given only when the address is positively known to be
2541 undeliverable. Sigh. Also, for ETRN, 458 is given on refusal, and for AUTH,
2544 From Exim 4.63, it is possible to override the response code details by
2545 providing a suitable response code string at the start of the message provided
2546 in user_msg. The code's first digit is checked for validity.
2549 where where the ACL was called from
2551 user_msg a message that can be included in an SMTP response
2552 log_msg a message for logging
2554 Returns: 0 in most cases
2555 2 if the failure code was FAIL_DROP, in which case the
2556 SMTP connection should be dropped (this value fits with the
2557 "done" variable in smtp_setup_msg() below)
2561 smtp_handle_acl_fail(int where, int rc, uschar *user_msg, uschar *log_msg)
2563 BOOL drop = rc == FAIL_DROP;
2567 uschar *sender_info = US"";
2569 #ifdef WITH_CONTENT_SCAN
2570 (where == ACL_WHERE_MIME)? US"during MIME ACL checks" :
2572 (where == ACL_WHERE_PREDATA)? US"DATA" :
2573 (where == ACL_WHERE_DATA)? US"after DATA" :
2574 #ifdef EXPERIMENTAL_PRDR
2575 (where == ACL_WHERE_PRDR)? US"after DATA PRDR" :
2577 (smtp_cmd_data == NULL)?
2578 string_sprintf("%s in \"connect\" ACL", acl_wherenames[where]) :
2579 string_sprintf("%s %s", acl_wherenames[where], smtp_cmd_data);
2581 if (drop) rc = FAIL;
2583 /* Set the default SMTP code, and allow a user message to change it. */
2585 smtp_code = (rc != FAIL)? US"451" : acl_wherecodes[where];
2586 smtp_message_code(&smtp_code, &codelen, &user_msg, &log_msg);
2588 /* We used to have sender_address here; however, there was a bug that was not
2589 updating sender_address after a rewrite during a verify. When this bug was
2590 fixed, sender_address at this point became the rewritten address. I'm not sure
2591 this is what should be logged, so I've changed to logging the unrewritten
2592 address to retain backward compatibility. */
2594 #ifndef WITH_CONTENT_SCAN
2595 if (where == ACL_WHERE_RCPT || where == ACL_WHERE_DATA)
2597 if (where == ACL_WHERE_RCPT || where == ACL_WHERE_DATA || where == ACL_WHERE_MIME)
2600 sender_info = string_sprintf("F=<%s>%s%s%s%s ",
2601 sender_address_unrewritten ? sender_address_unrewritten : sender_address,
2602 sender_host_authenticated ? US" A=" : US"",
2603 sender_host_authenticated ? sender_host_authenticated : US"",
2604 sender_host_authenticated && authenticated_id ? US":" : US"",
2605 sender_host_authenticated && authenticated_id ? authenticated_id : US""
2609 /* If there's been a sender verification failure with a specific message, and
2610 we have not sent a response about it yet, do so now, as a preliminary line for
2611 failures, but not defers. However, always log it for defer, and log it for fail
2612 unless the sender_verify_fail log selector has been turned off. */
2614 if (sender_verified_failed != NULL &&
2615 !testflag(sender_verified_failed, af_sverify_told))
2617 BOOL save_rcpt_in_progress = rcpt_in_progress;
2618 rcpt_in_progress = FALSE; /* So as not to treat these as the error */
2620 setflag(sender_verified_failed, af_sverify_told);
2622 if (rc != FAIL || (log_extra_selector & LX_sender_verify_fail) != 0)
2623 log_write(0, LOG_MAIN|LOG_REJECT, "%s sender verify %s for <%s>%s",
2624 host_and_ident(TRUE),
2625 ((sender_verified_failed->special_action & 255) == DEFER)? "defer":"fail",
2626 sender_verified_failed->address,
2627 (sender_verified_failed->message == NULL)? US"" :
2628 string_sprintf(": %s", sender_verified_failed->message));
2630 if (rc == FAIL && sender_verified_failed->user_message != NULL)
2631 smtp_respond(smtp_code, codelen, FALSE, string_sprintf(
2632 testflag(sender_verified_failed, af_verify_pmfail)?
2633 "Postmaster verification failed while checking <%s>\n%s\n"
2634 "Several RFCs state that you are required to have a postmaster\n"
2635 "mailbox for each mail domain. This host does not accept mail\n"
2636 "from domains whose servers reject the postmaster address."
2638 testflag(sender_verified_failed, af_verify_nsfail)?
2639 "Callback setup failed while verifying <%s>\n%s\n"
2640 "The initial connection, or a HELO or MAIL FROM:<> command was\n"
2641 "rejected. Refusing MAIL FROM:<> does not help fight spam, disregards\n"
2642 "RFC requirements, and stops you from receiving standard bounce\n"
2643 "messages. This host does not accept mail from domains whose servers\n"
2646 "Verification failed for <%s>\n%s",
2647 sender_verified_failed->address,
2648 sender_verified_failed->user_message));
2650 rcpt_in_progress = save_rcpt_in_progress;
2653 /* Sort out text for logging */
2655 log_msg = (log_msg == NULL)? US"" : string_sprintf(": %s", log_msg);
2656 lognl = Ustrchr(log_msg, '\n');
2657 if (lognl != NULL) *lognl = 0;
2659 /* Send permanent failure response to the command, but the code used isn't
2660 always a 5xx one - see comments at the start of this function. If the original
2661 rc was FAIL_DROP we drop the connection and yield 2. */
2663 if (rc == FAIL) smtp_respond(smtp_code, codelen, TRUE, (user_msg == NULL)?
2664 US"Administrative prohibition" : user_msg);
2666 /* Send temporary failure response to the command. Don't give any details,
2667 unless acl_temp_details is set. This is TRUE for a callout defer, a "defer"
2668 verb, and for a header verify when smtp_return_error_details is set.
2670 This conditional logic is all somewhat of a mess because of the odd
2671 interactions between temp_details and return_error_details. One day it should
2672 be re-implemented in a tidier fashion. */
2676 if (acl_temp_details && user_msg != NULL)
2678 if (smtp_return_error_details &&
2679 sender_verified_failed != NULL &&
2680 sender_verified_failed->message != NULL)
2682 smtp_respond(smtp_code, codelen, FALSE, sender_verified_failed->message);
2684 smtp_respond(smtp_code, codelen, TRUE, user_msg);
2687 smtp_respond(smtp_code, codelen, TRUE,
2688 US"Temporary local problem - please try later");
2691 /* Log the incident to the logs that are specified by log_reject_target
2692 (default main, reject). This can be empty to suppress logging of rejections. If
2693 the connection is not forcibly to be dropped, return 0. Otherwise, log why it
2694 is closing if required and return 2. */
2696 if (log_reject_target != 0)
2697 log_write(0, log_reject_target, "%s %s%srejected %s%s",
2698 host_and_ident(TRUE),
2699 sender_info, (rc == FAIL)? US"" : US"temporarily ", what, log_msg);
2701 if (!drop) return 0;
2703 log_write(L_smtp_connection, LOG_MAIN, "%s closed by DROP in ACL",
2704 smtp_get_connection_info());
2706 /* Run the not-quit ACL, but without any custom messages. This should not be a
2707 problem, because we get here only if some other ACL has issued "drop", and
2708 in that case, *its* custom messages will have been used above. */
2710 smtp_notquit_exit(US"acl-drop", NULL, NULL);
2717 /*************************************************
2718 * Handle SMTP exit when QUIT is not given *
2719 *************************************************/
2721 /* This function provides a logging/statistics hook for when an SMTP connection
2722 is dropped on the floor or the other end goes away. It's a global function
2723 because it's called from receive.c as well as this module. As well as running
2724 the NOTQUIT ACL, if there is one, this function also outputs a final SMTP
2725 response, either with a custom message from the ACL, or using a default. There
2726 is one case, however, when no message is output - after "drop". In that case,
2727 the ACL that obeyed "drop" has already supplied the custom message, and NULL is
2728 passed to this function.
2730 In case things go wrong while processing this function, causing an error that
2731 may re-enter this funtion, there is a recursion check.
2734 reason What $smtp_notquit_reason will be set to in the ACL;
2735 if NULL, the ACL is not run
2736 code The error code to return as part of the response
2737 defaultrespond The default message if there's no user_msg
2743 smtp_notquit_exit(uschar *reason, uschar *code, uschar *defaultrespond, ...)
2746 uschar *user_msg = NULL;
2747 uschar *log_msg = NULL;
2749 /* Check for recursive acll */
2751 if (smtp_exit_function_called)
2753 log_write(0, LOG_PANIC, "smtp_notquit_exit() called more than once (%s)",
2757 smtp_exit_function_called = TRUE;
2759 /* Call the not-QUIT ACL, if there is one, unless no reason is given. */
2761 if (acl_smtp_notquit != NULL && reason != NULL)
2763 smtp_notquit_reason = reason;
2764 rc = acl_check(ACL_WHERE_NOTQUIT, NULL, acl_smtp_notquit, &user_msg,
2767 log_write(0, LOG_MAIN|LOG_PANIC, "ACL for not-QUIT returned ERROR: %s",
2771 /* Write an SMTP response if we are expected to give one. As the default
2772 responses are all internal, they should always fit in the buffer, but code a
2773 warning, just in case. Note that string_vformat() still leaves a complete
2774 string, even if it is incomplete. */
2776 if (code != NULL && defaultrespond != NULL)
2778 if (user_msg == NULL)
2782 va_start(ap, defaultrespond);
2783 if (!string_vformat(buffer, sizeof(buffer), CS defaultrespond, ap))
2784 log_write(0, LOG_MAIN|LOG_PANIC, "string too large in smtp_notquit_exit()");
2785 smtp_printf("%s %s\r\n", code, buffer);
2789 smtp_respond(code, 3, TRUE, user_msg);
2797 /*************************************************
2798 * Verify HELO argument *
2799 *************************************************/
2801 /* This function is called if helo_verify_hosts or helo_try_verify_hosts is
2802 matched. It is also called from ACL processing if verify = helo is used and
2803 verification was not previously tried (i.e. helo_try_verify_hosts was not
2804 matched). The result of its processing is to set helo_verified and
2805 helo_verify_failed. These variables should both be FALSE for this function to
2808 Note that EHLO/HELO is legitimately allowed to quote an address literal. Allow
2809 for IPv6 ::ffff: literals.
2812 Returns: TRUE if testing was completed;
2813 FALSE on a temporary failure
2817 smtp_verify_helo(void)
2821 HDEBUG(D_receive) debug_printf("verifying EHLO/HELO argument \"%s\"\n",
2824 if (sender_helo_name == NULL)
2826 HDEBUG(D_receive) debug_printf("no EHLO/HELO command was issued\n");
2829 /* Deal with the case of -bs without an IP address */
2831 else if (sender_host_address == NULL)
2833 HDEBUG(D_receive) debug_printf("no client IP address: assume success\n");
2834 helo_verified = TRUE;
2837 /* Deal with the more common case when there is a sending IP address */
2839 else if (sender_helo_name[0] == '[')
2841 helo_verified = Ustrncmp(sender_helo_name+1, sender_host_address,
2842 Ustrlen(sender_host_address)) == 0;
2847 if (strncmpic(sender_host_address, US"::ffff:", 7) == 0)
2848 helo_verified = Ustrncmp(sender_helo_name + 1,
2849 sender_host_address + 7, Ustrlen(sender_host_address) - 7) == 0;
2854 { if (helo_verified) debug_printf("matched host address\n"); }
2857 /* Do a reverse lookup if one hasn't already given a positive or negative
2858 response. If that fails, or the name doesn't match, try checking with a forward
2863 if (sender_host_name == NULL && !host_lookup_failed)
2864 yield = host_name_lookup() != DEFER;
2866 /* If a host name is known, check it and all its aliases. */
2868 if (sender_host_name != NULL)
2870 helo_verified = strcmpic(sender_host_name, sender_helo_name) == 0;
2874 HDEBUG(D_receive) debug_printf("matched host name\n");
2878 uschar **aliases = sender_host_aliases;
2879 while (*aliases != NULL)
2881 helo_verified = strcmpic(*aliases++, sender_helo_name) == 0;
2882 if (helo_verified) break;
2887 debug_printf("matched alias %s\n", *(--aliases));
2892 /* Final attempt: try a forward lookup of the helo name */
2898 h.name = sender_helo_name;
2902 HDEBUG(D_receive) debug_printf("getting IP address for %s\n",
2904 rc = host_find_byname(&h, NULL, 0, NULL, TRUE);
2905 if (rc == HOST_FOUND || rc == HOST_FOUND_LOCAL)
2910 if (Ustrcmp(hh->address, sender_host_address) == 0)
2912 helo_verified = TRUE;
2914 debug_printf("IP address for %s matches calling address\n",
2924 if (!helo_verified) helo_verify_failed = TRUE; /* We've tried ... */
2931 /*************************************************
2932 * Send user response message *
2933 *************************************************/
2935 /* This function is passed a default response code and a user message. It calls
2936 smtp_message_code() to check and possibly modify the response code, and then
2937 calls smtp_respond() to transmit the response. I put this into a function
2938 just to avoid a lot of repetition.
2941 code the response code
2942 user_msg the user message
2948 smtp_user_msg(uschar *code, uschar *user_msg)
2951 smtp_message_code(&code, &len, &user_msg, NULL);
2952 smtp_respond(code, len, TRUE, user_msg);
2957 /*************************************************
2958 * Initialize for SMTP incoming message *
2959 *************************************************/
2961 /* This function conducts the initial dialogue at the start of an incoming SMTP
2962 message, and builds a list of recipients. However, if the incoming message
2963 is part of a batch (-bS option) a separate function is called since it would
2964 be messy having tests splattered about all over this function. This function
2965 therefore handles the case where interaction is occurring. The input and output
2966 files are set up in smtp_in and smtp_out.
2968 The global recipients_list is set to point to a vector of recipient_item
2969 blocks, whose number is given by recipients_count. This is extended by the
2970 receive_add_recipient() function. The global variable sender_address is set to
2971 the sender's address. The yield is +1 if a message has been successfully
2972 started, 0 if a QUIT command was encountered or the connection was refused from
2973 the particular host, or -1 if the connection was lost.
2977 Returns: > 0 message successfully started (reached DATA)
2978 = 0 QUIT read or end of file reached or call refused
2983 smtp_setup_msg(void)
2986 BOOL toomany = FALSE;
2987 BOOL discarded = FALSE;
2988 BOOL last_was_rej_mail = FALSE;
2989 BOOL last_was_rcpt = FALSE;
2990 void *reset_point = store_get(0);
2992 DEBUG(D_receive) debug_printf("smtp_setup_msg entered\n");
2994 /* Reset for start of new message. We allow one RSET not to be counted as a
2995 nonmail command, for those MTAs that insist on sending it between every
2996 message. Ditto for EHLO/HELO and for STARTTLS, to allow for going in and out of
2997 TLS between messages (an Exim client may do this if it has messages queued up
2998 for the host). Note: we do NOT reset AUTH at this point. */
3000 smtp_reset(reset_point);
3001 message_ended = END_NOTSTARTED;
3003 cmd_list[CMD_LIST_RSET].is_mail_cmd = TRUE;
3004 cmd_list[CMD_LIST_HELO].is_mail_cmd = TRUE;
3005 cmd_list[CMD_LIST_EHLO].is_mail_cmd = TRUE;
3007 cmd_list[CMD_LIST_STARTTLS].is_mail_cmd = TRUE;
3010 /* Set the local signal handler for SIGTERM - it tries to end off tidily */
3012 os_non_restarting_signal(SIGTERM, command_sigterm_handler);
3014 /* Batched SMTP is handled in a different function. */
3016 if (smtp_batched_input) return smtp_setup_batch_msg();
3018 /* Deal with SMTP commands. This loop is exited by setting done to a POSITIVE
3019 value. The values are 2 larger than the required yield of the function. */
3024 uschar *etrn_command;
3025 uschar *etrn_serialize_key;
3027 uschar *log_msg, *smtp_code;
3028 uschar *user_msg = NULL;
3029 uschar *recipient = NULL;
3030 uschar *hello = NULL;
3031 uschar *set_id = NULL;
3033 BOOL was_rej_mail = FALSE;
3034 BOOL was_rcpt = FALSE;
3035 void (*oldsignal)(int);
3037 int start, end, sender_domain, recipient_domain;
3042 switch(smtp_read_command(TRUE))
3044 /* The AUTH command is not permitted to occur inside a transaction, and may
3045 occur successfully only once per connection. Actually, that isn't quite
3046 true. When TLS is started, all previous information about a connection must
3047 be discarded, so a new AUTH is permitted at that time.
3049 AUTH may only be used when it has been advertised. However, it seems that
3050 there are clients that send AUTH when it hasn't been advertised, some of
3051 them even doing this after HELO. And there are MTAs that accept this. Sigh.
3052 So there's a get-out that allows this to happen.
3054 AUTH is initially labelled as a "nonmail command" so that one occurrence
3055 doesn't get counted. We change the label here so that multiple failing
3056 AUTHS will eventually hit the nonmail threshold. */
3060 authentication_failed = TRUE;
3061 cmd_list[CMD_LIST_AUTH].is_mail_cmd = FALSE;
3063 if (!auth_advertised && !allow_auth_unadvertised)
3065 done = synprot_error(L_smtp_protocol_error, 503, NULL,
3066 US"AUTH command used when not advertised");
3069 if (sender_host_authenticated != NULL)
3071 done = synprot_error(L_smtp_protocol_error, 503, NULL,
3072 US"already authenticated");
3075 if (sender_address != NULL)
3077 done = synprot_error(L_smtp_protocol_error, 503, NULL,
3078 US"not permitted in mail transaction");
3084 if (acl_smtp_auth != NULL)
3086 rc = acl_check(ACL_WHERE_AUTH, NULL, acl_smtp_auth, &user_msg, &log_msg);
3089 done = smtp_handle_acl_fail(ACL_WHERE_AUTH, rc, user_msg, log_msg);
3094 /* Find the name of the requested authentication mechanism. */
3097 while ((c = *smtp_cmd_data) != 0 && !isspace(c))
3099 if (!isalnum(c) && c != '-' && c != '_')
3101 done = synprot_error(L_smtp_syntax_error, 501, NULL,
3102 US"invalid character in authentication mechanism name");
3108 /* If not at the end of the line, we must be at white space. Terminate the
3109 name and move the pointer on to any data that may be present. */
3111 if (*smtp_cmd_data != 0)
3113 *smtp_cmd_data++ = 0;
3114 while (isspace(*smtp_cmd_data)) smtp_cmd_data++;
3117 /* Search for an authentication mechanism which is configured for use
3118 as a server and which has been advertised (unless, sigh, allow_auth_
3119 unadvertised is set). */
3121 for (au = auths; au != NULL; au = au->next)
3123 if (strcmpic(s, au->public_name) == 0 && au->server &&
3124 (au->advertised || allow_auth_unadvertised)) break;
3129 done = synprot_error(L_smtp_protocol_error, 504, NULL,
3130 string_sprintf("%s authentication mechanism not supported", s));
3134 /* Run the checking code, passing the remainder of the command line as
3135 data. Initials the $auth<n> variables as empty. Initialize $0 empty and set
3136 it as the only set numerical variable. The authenticator may set $auth<n>
3137 and also set other numeric variables. The $auth<n> variables are preferred
3138 nowadays; the numerical variables remain for backwards compatibility.
3140 Afterwards, have a go at expanding the set_id string, even if
3141 authentication failed - for bad passwords it can be useful to log the
3142 userid. On success, require set_id to expand and exist, and put it in
3143 authenticated_id. Save this in permanent store, as the working store gets
3144 reset at HELO, RSET, etc. */
3146 for (i = 0; i < AUTH_VARS; i++) auth_vars[i] = NULL;
3148 expand_nlength[0] = 0; /* $0 contains nothing */
3150 c = (au->info->servercode)(au, smtp_cmd_data);
3151 if (au->set_id != NULL) set_id = expand_string(au->set_id);
3152 expand_nmax = -1; /* Reset numeric variables */
3153 for (i = 0; i < AUTH_VARS; i++) auth_vars[i] = NULL; /* Reset $auth<n> */
3155 /* The value of authenticated_id is stored in the spool file and printed in
3156 log lines. It must not contain binary zeros or newline characters. In
3157 normal use, it never will, but when playing around or testing, this error
3158 can (did) happen. To guard against this, ensure that the id contains only
3159 printing characters. */
3161 if (set_id != NULL) set_id = string_printing(set_id);
3163 /* For the non-OK cases, set up additional logging data if set_id
3168 if (set_id != NULL && *set_id != 0)
3169 set_id = string_sprintf(" (set_id=%s)", set_id);
3173 /* Switch on the result */
3178 if (au->set_id == NULL || set_id != NULL) /* Complete success */
3180 if (set_id != NULL) authenticated_id = string_copy_malloc(set_id);
3181 sender_host_authenticated = au->name;
3182 authentication_failed = FALSE;
3183 authenticated_fail_id = NULL; /* Impossible to already be set? */
3185 protocols[pextend + pauthed + ((tls_in.active >= 0)? pcrpted:0)] +
3186 ((sender_host_address != NULL)? pnlocal : 0);
3187 s = ss = US"235 Authentication succeeded";
3188 authenticated_by = au;
3192 /* Authentication succeeded, but we failed to expand the set_id string.
3193 Treat this as a temporary error. */
3195 auth_defer_msg = expand_string_message;
3199 if (set_id != NULL) authenticated_fail_id = string_copy_malloc(set_id);
3200 s = string_sprintf("435 Unable to authenticate at present%s",
3201 auth_defer_user_msg);
3202 ss = string_sprintf("435 Unable to authenticate at present%s: %s",
3203 set_id, auth_defer_msg);
3207 s = ss = US"501 Invalid base64 data";
3211 s = ss = US"501 Authentication cancelled";
3215 s = ss = US"553 Initial data not expected";
3219 if (set_id != NULL) authenticated_fail_id = string_copy_malloc(set_id);
3220 s = US"535 Incorrect authentication data";
3221 ss = string_sprintf("535 Incorrect authentication data%s", set_id);
3225 if (set_id != NULL) authenticated_fail_id = string_copy_malloc(set_id);
3226 s = US"435 Internal error";
3227 ss = string_sprintf("435 Internal error%s: return %d from authentication "
3228 "check", set_id, c);
3232 smtp_printf("%s\r\n", s);
3234 log_write(0, LOG_MAIN|LOG_REJECT, "%s authenticator failed for %s: %s",
3235 au->name, host_and_ident(FALSE), ss);
3237 break; /* AUTH_CMD */
3239 /* The HELO/EHLO commands are permitted to appear in the middle of a
3240 session as well as at the beginning. They have the effect of a reset in
3241 addition to their other functions. Their absence at the start cannot be
3242 taken to be an error.
3246 If the EHLO command is not acceptable to the SMTP server, 501, 500,
3247 or 502 failure replies MUST be returned as appropriate. The SMTP
3248 server MUST stay in the same state after transmitting these replies
3249 that it was in before the EHLO was received.
3251 Therefore, we do not do the reset until after checking the command for
3252 acceptability. This change was made for Exim release 4.11. Previously
3253 it did the reset first. */
3266 HELO_EHLO: /* Common code for HELO and EHLO */
3267 cmd_list[CMD_LIST_HELO].is_mail_cmd = FALSE;
3268 cmd_list[CMD_LIST_EHLO].is_mail_cmd = FALSE;
3270 /* Reject the HELO if its argument was invalid or non-existent. A
3271 successful check causes the argument to be saved in malloc store. */
3273 if (!check_helo(smtp_cmd_data))
3275 smtp_printf("501 Syntactically invalid %s argument(s)\r\n", hello);
3277 log_write(0, LOG_MAIN|LOG_REJECT, "rejected %s from %s: syntactically "
3278 "invalid argument(s): %s", hello, host_and_ident(FALSE),
3279 (*smtp_cmd_argument == 0)? US"(no argument given)" :
3280 string_printing(smtp_cmd_argument));
3282 if (++synprot_error_count > smtp_max_synprot_errors)
3284 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
3285 "syntax or protocol errors (last command was \"%s\")",
3286 host_and_ident(FALSE), smtp_cmd_buffer);
3293 /* If sender_host_unknown is true, we have got here via the -bs interface,
3294 not called from inetd. Otherwise, we are running an IP connection and the
3295 host address will be set. If the helo name is the primary name of this
3296 host and we haven't done a reverse lookup, force one now. If helo_required
3297 is set, ensure that the HELO name matches the actual host. If helo_verify
3298 is set, do the same check, but softly. */
3300 if (!sender_host_unknown)
3302 BOOL old_helo_verified = helo_verified;
3303 uschar *p = smtp_cmd_data;
3305 while (*p != 0 && !isspace(*p)) { *p = tolower(*p); p++; }
3308 /* Force a reverse lookup if HELO quoted something in helo_lookup_domains
3309 because otherwise the log can be confusing. */
3311 if (sender_host_name == NULL &&
3312 (deliver_domain = sender_helo_name, /* set $domain */
3313 match_isinlist(sender_helo_name, &helo_lookup_domains, 0,
3314 &domainlist_anchor, NULL, MCL_DOMAIN, TRUE, NULL)) == OK)
3315 (void)host_name_lookup();
3317 /* Rebuild the fullhost info to include the HELO name (and the real name
3318 if it was looked up.) */
3320 host_build_sender_fullhost(); /* Rebuild */
3321 set_process_info("handling%s incoming connection from %s",
3322 (tls_in.active >= 0)? " TLS" : "", host_and_ident(FALSE));
3324 /* Verify if configured. This doesn't give much security, but it does
3325 make some people happy to be able to do it. If helo_required is set,
3326 (host matches helo_verify_hosts) failure forces rejection. If helo_verify
3327 is set (host matches helo_try_verify_hosts), it does not. This is perhaps
3328 now obsolescent, since the verification can now be requested selectively
3331 helo_verified = helo_verify_failed = FALSE;
3332 if (helo_required || helo_verify)
3334 BOOL tempfail = !smtp_verify_helo();
3339 smtp_printf("%d %s argument does not match calling host\r\n",
3340 tempfail? 451 : 550, hello);
3341 log_write(0, LOG_MAIN|LOG_REJECT, "%srejected \"%s %s\" from %s",
3342 tempfail? "temporarily " : "",
3343 hello, sender_helo_name, host_and_ident(FALSE));
3344 helo_verified = old_helo_verified;
3345 break; /* End of HELO/EHLO processing */
3347 HDEBUG(D_all) debug_printf("%s verification failed but host is in "
3348 "helo_try_verify_hosts\n", hello);
3353 #ifdef EXPERIMENTAL_SPF
3354 /* set up SPF context */
3355 spf_init(sender_helo_name, sender_host_address);
3358 /* Apply an ACL check if one is defined; afterwards, recheck
3359 synchronization in case the client started sending in a delay. */
3361 if (acl_smtp_helo != NULL)
3363 rc = acl_check(ACL_WHERE_HELO, NULL, acl_smtp_helo, &user_msg, &log_msg);
3366 done = smtp_handle_acl_fail(ACL_WHERE_HELO, rc, user_msg, log_msg);
3367 sender_helo_name = NULL;
3368 host_build_sender_fullhost(); /* Rebuild */
3371 else if (!check_sync()) goto SYNC_FAILURE;
3374 /* Generate an OK reply. The default string includes the ident if present,
3375 and also the IP address if present. Reflecting back the ident is intended
3376 as a deterrent to mail forgers. For maximum efficiency, and also because
3377 some broken systems expect each response to be in a single packet, arrange
3378 that the entire reply is sent in one write(). */
3380 auth_advertised = FALSE;
3381 pipelining_advertised = FALSE;
3383 tls_advertised = FALSE;
3386 smtp_code = US"250 "; /* Default response code plus space*/
3387 if (user_msg == NULL)
3389 s = string_sprintf("%.3s %s Hello %s%s%s",
3391 smtp_active_hostname,
3392 (sender_ident == NULL)? US"" : sender_ident,
3393 (sender_ident == NULL)? US"" : US" at ",
3394 (sender_host_name == NULL)? sender_helo_name : sender_host_name);
3399 if (sender_host_address != NULL)
3401 s = string_cat(s, &size, &ptr, US" [", 2);
3402 s = string_cat(s, &size, &ptr, sender_host_address,
3403 Ustrlen(sender_host_address));
3404 s = string_cat(s, &size, &ptr, US"]", 1);
3408 /* A user-supplied EHLO greeting may not contain more than one line. Note
3409 that the code returned by smtp_message_code() includes the terminating
3410 whitespace character. */
3416 smtp_message_code(&smtp_code, &codelen, &user_msg, NULL);
3417 s = string_sprintf("%.*s%s", codelen, smtp_code, user_msg);
3418 if ((ss = strpbrk(CS s, "\r\n")) != NULL)
3420 log_write(0, LOG_MAIN|LOG_PANIC, "EHLO/HELO response must not contain "
3421 "newlines: message truncated: %s", string_printing(s));
3428 s = string_cat(s, &size, &ptr, US"\r\n", 2);
3430 /* If we received EHLO, we must create a multiline response which includes
3431 the functions supported. */
3437 /* I'm not entirely happy with this, as an MTA is supposed to check
3438 that it has enough room to accept a message of maximum size before
3439 it sends this. However, there seems little point in not sending it.
3440 The actual size check happens later at MAIL FROM time. By postponing it
3441 till then, VRFY and EXPN can be used after EHLO when space is short. */
3443 if (thismessage_size_limit > 0)
3445 sprintf(CS big_buffer, "%.3s-SIZE %d\r\n", smtp_code,
3446 thismessage_size_limit);
3447 s = string_cat(s, &size, &ptr, big_buffer, Ustrlen(big_buffer));
3451 s = string_cat(s, &size, &ptr, smtp_code, 3);
3452 s = string_cat(s, &size, &ptr, US"-SIZE\r\n", 7);
3455 /* Exim does not do protocol conversion or data conversion. It is 8-bit
3456 clean; if it has an 8-bit character in its hand, it just sends it. It
3457 cannot therefore specify 8BITMIME and remain consistent with the RFCs.
3458 However, some users want this option simply in order to stop MUAs
3459 mangling messages that contain top-bit-set characters. It is therefore
3460 provided as an option. */
3462 if (accept_8bitmime)
3464 s = string_cat(s, &size, &ptr, smtp_code, 3);
3465 s = string_cat(s, &size, &ptr, US"-8BITMIME\r\n", 11);
3468 /* Advertise ETRN if there's an ACL checking whether a host is
3469 permitted to issue it; a check is made when any host actually tries. */
3471 if (acl_smtp_etrn != NULL)
3473 s = string_cat(s, &size, &ptr, smtp_code, 3);
3474 s = string_cat(s, &size, &ptr, US"-ETRN\r\n", 7);
3477 /* Advertise EXPN if there's an ACL checking whether a host is
3478 permitted to issue it; a check is made when any host actually tries. */
3480 if (acl_smtp_expn != NULL)
3482 s = string_cat(s, &size, &ptr, smtp_code, 3);
3483 s = string_cat(s, &size, &ptr, US"-EXPN\r\n", 7);
3486 /* Exim is quite happy with pipelining, so let the other end know that
3487 it is safe to use it, unless advertising is disabled. */
3489 if (pipelining_enable &&
3490 verify_check_host(&pipelining_advertise_hosts) == OK)
3492 s = string_cat(s, &size, &ptr, smtp_code, 3);
3493 s = string_cat(s, &size, &ptr, US"-PIPELINING\r\n", 13);
3494 sync_cmd_limit = NON_SYNC_CMD_PIPELINING;
3495 pipelining_advertised = TRUE;
3499 /* If any server authentication mechanisms are configured, advertise
3500 them if the current host is in auth_advertise_hosts. The problem with
3501 advertising always is that some clients then require users to
3502 authenticate (and aren't configurable otherwise) even though it may not
3503 be necessary (e.g. if the host is in host_accept_relay).
3505 RFC 2222 states that SASL mechanism names contain only upper case
3506 letters, so output the names in upper case, though we actually recognize
3507 them in either case in the AUTH command. */
3511 if (verify_check_host(&auth_advertise_hosts) == OK)
3515 for (au = auths; au != NULL; au = au->next)
3517 if (au->server && (au->advertise_condition == NULL ||
3518 expand_check_condition(au->advertise_condition, au->name,
3519 US"authenticator")))
3524 s = string_cat(s, &size, &ptr, smtp_code, 3);
3525 s = string_cat(s, &size, &ptr, US"-AUTH", 5);
3527 auth_advertised = TRUE;
3530 s = string_cat(s, &size, &ptr, US" ", 1);
3531 s = string_cat(s, &size, &ptr, au->public_name,
3532 Ustrlen(au->public_name));
3533 while (++saveptr < ptr) s[saveptr] = toupper(s[saveptr]);
3534 au->advertised = TRUE;
3536 else au->advertised = FALSE;
3538 if (!first) s = string_cat(s, &size, &ptr, US"\r\n", 2);
3542 /* Advertise TLS (Transport Level Security) aka SSL (Secure Socket Layer)
3543 if it has been included in the binary, and the host matches
3544 tls_advertise_hosts. We must *not* advertise if we are already in a
3545 secure connection. */
3548 if (tls_in.active < 0 &&
3549 verify_check_host(&tls_advertise_hosts) != FAIL)
3551 s = string_cat(s, &size, &ptr, smtp_code, 3);
3552 s = string_cat(s, &size, &ptr, US"-STARTTLS\r\n", 11);
3553 tls_advertised = TRUE;
3557 #ifdef EXPERIMENTAL_PRDR
3558 /* Per Recipient Data Response, draft by Eric A. Hall extending RFC */
3560 s = string_cat(s, &size, &ptr, smtp_code, 3);
3561 s = string_cat(s, &size, &ptr, US"-PRDR\r\n", 7);
3565 /* Finish off the multiline reply with one that is always available. */
3567 s = string_cat(s, &size, &ptr, smtp_code, 3);
3568 s = string_cat(s, &size, &ptr, US" HELP\r\n", 7);
3571 /* Terminate the string (for debug), write it, and note that HELO/EHLO
3577 if (tls_in.active >= 0) (void)tls_write(TRUE, s, ptr); else
3581 int i = fwrite(s, 1, ptr, smtp_out); i = i; /* compiler quietening */
3586 while ((cr = Ustrchr(s, '\r')) != NULL) /* lose CRs */
3587 memmove(cr, cr + 1, (ptr--) - (cr - s));
3588 debug_printf("SMTP>> %s", s);
3592 /* Reset the protocol and the state, abandoning any previous message. */
3594 received_protocol = (esmtp?
3596 ((sender_host_authenticated != NULL)? pauthed : 0) +
3597 ((tls_in.active >= 0)? pcrpted : 0)]
3599 protocols[pnormal + ((tls_in.active >= 0)? pcrpted : 0)])
3601 ((sender_host_address != NULL)? pnlocal : 0);
3603 smtp_reset(reset_point);
3605 break; /* HELO/EHLO */
3608 /* The MAIL command requires an address as an operand. All we do
3609 here is to parse it for syntactic correctness. The form "<>" is
3610 a special case which converts into an empty string. The start/end
3611 pointers in the original are not used further for this address, as
3612 it is the canonical extracted address which is all that is kept. */
3616 smtp_mailcmd_count++; /* Count for limit and ratelimit */
3617 was_rej_mail = TRUE; /* Reset if accepted */
3618 env_mail_type_t * mail_args; /* Sanity check & validate args */
3620 if (helo_required && !helo_seen)
3622 smtp_printf("503 HELO or EHLO required\r\n");
3623 log_write(0, LOG_MAIN|LOG_REJECT, "rejected MAIL from %s: no "
3624 "HELO/EHLO given", host_and_ident(FALSE));
3628 if (sender_address != NULL)
3630 done = synprot_error(L_smtp_protocol_error, 503, NULL,
3631 US"sender already given");
3635 if (smtp_cmd_data[0] == 0)
3637 done = synprot_error(L_smtp_protocol_error, 501, NULL,
3638 US"MAIL must have an address operand");
3642 /* Check to see if the limit for messages per connection would be
3643 exceeded by accepting further messages. */
3645 if (smtp_accept_max_per_connection > 0 &&
3646 smtp_mailcmd_count > smtp_accept_max_per_connection)
3648 smtp_printf("421 too many messages in this connection\r\n");
3649 log_write(0, LOG_MAIN|LOG_REJECT, "rejected MAIL command %s: too many "
3650 "messages in one connection", host_and_ident(TRUE));
3654 /* Reset for start of message - even if this is going to fail, we
3655 obviously need to throw away any previous data. */
3657 smtp_reset(reset_point);
3659 sender_data = recipient_data = NULL;
3661 /* Loop, checking for ESMTP additions to the MAIL FROM command. */
3665 uschar *name, *value, *end;
3666 unsigned long int size;
3667 BOOL arg_error = FALSE;
3669 if (!extract_option(&name, &value)) break;
3671 for (mail_args = env_mail_type_list;
3672 (char *)mail_args < (char *)env_mail_type_list + sizeof(env_mail_type_list);
3676 if (strcmpic(name, mail_args->name) == 0)
3679 if (mail_args->need_value && strcmpic(value, US"") == 0)
3682 switch(mail_args->value)
3684 /* Handle SIZE= by reading the value. We don't do the check till later,
3685 in order to be able to log the sender address on failure. */
3686 case ENV_MAIL_OPT_SIZE:
3687 if (((size = Ustrtoul(value, &end, 10)), *end == 0))
3689 if ((size == ULONG_MAX && errno == ERANGE) || size > INT_MAX)
3691 message_size = (int)size;
3697 /* If this session was initiated with EHLO and accept_8bitmime is set,
3698 Exim will have indicated that it supports the BODY=8BITMIME option. In
3699 fact, it does not support this according to the RFCs, in that it does not
3700 take any special action for forwarding messages containing 8-bit
3701 characters. That is why accept_8bitmime is not the default setting, but
3702 some sites want the action that is provided. We recognize both "8BITMIME"
3703 and "7BIT" as body types, but take no action. */
3704 case ENV_MAIL_OPT_BODY:
3705 if (accept_8bitmime) {
3706 if (strcmpic(value, US"8BITMIME") == 0) {
3708 } else if (strcmpic(value, US"7BIT") == 0) {
3712 done = synprot_error(L_smtp_syntax_error, 501, NULL,
3713 US"invalid data for BODY");
3716 DEBUG(D_receive) debug_printf("8BITMIME: %d\n", body_8bitmime);
3722 /* Handle the AUTH extension. If the value given is not "<>" and either
3723 the ACL says "yes" or there is no ACL but the sending host is
3724 authenticated, we set it up as the authenticated sender. However, if the
3725 authenticator set a condition to be tested, we ignore AUTH on MAIL unless
3726 the condition is met. The value of AUTH is an xtext, which means that +,
3727 = and cntrl chars are coded in hex; however "<>" is unaffected by this
3729 case ENV_MAIL_OPT_AUTH:
3730 if (Ustrcmp(value, "<>") != 0)
3735 if (auth_xtextdecode(value, &authenticated_sender) < 0)
3737 /* Put back terminator overrides for error message */
3740 done = synprot_error(L_smtp_syntax_error, 501, NULL,
3741 US"invalid data for AUTH");
3744 if (acl_smtp_mailauth == NULL)
3746 ignore_msg = US"client not authenticated";
3747 rc = (sender_host_authenticated != NULL)? OK : FAIL;
3751 ignore_msg = US"rejected by ACL";
3752 rc = acl_check(ACL_WHERE_MAILAUTH, NULL, acl_smtp_mailauth,
3753 &user_msg, &log_msg);
3759 if (authenticated_by == NULL ||
3760 authenticated_by->mail_auth_condition == NULL ||
3761 expand_check_condition(authenticated_by->mail_auth_condition,
3762 authenticated_by->name, US"authenticator"))
3763 break; /* Accept the AUTH */
3765 ignore_msg = US"server_mail_auth_condition failed";
3766 if (authenticated_id != NULL)
3767 ignore_msg = string_sprintf("%s: authenticated ID=\"%s\"",
3768 ignore_msg, authenticated_id);
3773 authenticated_sender = NULL;
3774 log_write(0, LOG_MAIN, "ignoring AUTH=%s from %s (%s)",
3775 value, host_and_ident(TRUE), ignore_msg);
3778 /* Should only get DEFER or ERROR here. Put back terminator
3779 overrides for error message */
3784 (void)smtp_handle_acl_fail(ACL_WHERE_MAILAUTH, rc, user_msg,
3791 #ifdef EXPERIMENTAL_PRDR
3792 case ENV_MAIL_OPT_PRDR:
3794 prdr_requested = TRUE;
3798 /* Unknown option. Stick back the terminator characters and break
3799 the loop. Do the name-terminator second as extract_option sets
3800 value==name when it found no equal-sign.
3801 An error for a malformed address will occur. */
3808 /* Break out of for loop if switch() had bad argument or
3809 when start of the email address is reached */
3810 if (arg_error) break;
3813 /* If we have passed the threshold for rate limiting, apply the current
3814 delay, and update it for next time, provided this is a limited host. */
3816 if (smtp_mailcmd_count > smtp_rlm_threshold &&
3817 verify_check_host(&smtp_ratelimit_hosts) == OK)
3819 DEBUG(D_receive) debug_printf("rate limit MAIL: delay %.3g sec\n",
3820 smtp_delay_mail/1000.0);
3821 millisleep((int)smtp_delay_mail);
3822 smtp_delay_mail *= smtp_rlm_factor;
3823 if (smtp_delay_mail > (double)smtp_rlm_limit)
3824 smtp_delay_mail = (double)smtp_rlm_limit;
3827 /* Now extract the address, first applying any SMTP-time rewriting. The
3828 TRUE flag allows "<>" as a sender address. */
3830 raw_sender = ((rewrite_existflags & rewrite_smtp) != 0)?
3831 rewrite_one(smtp_cmd_data, rewrite_smtp, NULL, FALSE, US"",
3832 global_rewrite_rules) : smtp_cmd_data;
3834 /* rfc821_domains = TRUE; << no longer needed */
3836 parse_extract_address(raw_sender, &errmess, &start, &end, &sender_domain,
3838 /* rfc821_domains = FALSE; << no longer needed */
3840 if (raw_sender == NULL)
3842 done = synprot_error(L_smtp_syntax_error, 501, smtp_cmd_data, errmess);
3846 sender_address = raw_sender;
3848 /* If there is a configured size limit for mail, check that this message
3849 doesn't exceed it. The check is postponed to this point so that the sender
3852 if (thismessage_size_limit > 0 && message_size > thismessage_size_limit)
3854 smtp_printf("552 Message size exceeds maximum permitted\r\n");
3855 log_write(L_size_reject,
3856 LOG_MAIN|LOG_REJECT, "rejected MAIL FROM:<%s> %s: "
3857 "message too big: size%s=%d max=%d",
3859 host_and_ident(TRUE),
3860 (message_size == INT_MAX)? ">" : "",
3862 thismessage_size_limit);
3863 sender_address = NULL;
3867 /* Check there is enough space on the disk unless configured not to.
3868 When smtp_check_spool_space is set, the check is for thismessage_size_limit
3869 plus the current message - i.e. we accept the message only if it won't
3870 reduce the space below the threshold. Add 5000 to the size to allow for
3871 overheads such as the Received: line and storing of recipients, etc.
3872 By putting the check here, even when SIZE is not given, it allow VRFY
3873 and EXPN etc. to be used when space is short. */
3875 if (!receive_check_fs(
3876 (smtp_check_spool_space && message_size >= 0)?
3877 message_size + 5000 : 0))
3879 smtp_printf("452 Space shortage, please try later\r\n");
3880 sender_address = NULL;
3884 /* If sender_address is unqualified, reject it, unless this is a locally
3885 generated message, or the sending host or net is permitted to send
3886 unqualified addresses - typically local machines behaving as MUAs -
3887 in which case just qualify the address. The flag is set above at the start
3888 of the SMTP connection. */
3890 if (sender_domain == 0 && sender_address[0] != 0)
3892 if (allow_unqualified_sender)
3894 sender_domain = Ustrlen(sender_address) + 1;
3895 sender_address = rewrite_address_qualify(sender_address, FALSE);
3896 DEBUG(D_receive) debug_printf("unqualified address %s accepted\n",
3901 smtp_printf("501 %s: sender address must contain a domain\r\n",
3903 log_write(L_smtp_syntax_error,
3904 LOG_MAIN|LOG_REJECT,
3905 "unqualified sender rejected: <%s> %s%s",
3907 host_and_ident(TRUE),
3909 sender_address = NULL;
3914 /* Apply an ACL check if one is defined, before responding. Afterwards,
3915 when pipelining is not advertised, do another sync check in case the ACL
3916 delayed and the client started sending in the meantime. */
3918 if (acl_smtp_mail == NULL) rc = OK; else
3920 rc = acl_check(ACL_WHERE_MAIL, NULL, acl_smtp_mail, &user_msg, &log_msg);
3921 if (rc == OK && !pipelining_advertised && !check_sync())
3925 if (rc == OK || rc == DISCARD)
3927 if (user_msg == NULL)
3928 smtp_printf("%s%s%s", US"250 OK",
3929 #ifdef EXPERIMENTAL_PRDR
3930 prdr_requested == TRUE ? US", PRDR Requested" :
3936 #ifdef EXPERIMENTAL_PRDR
3937 if ( prdr_requested == TRUE )
3938 user_msg = string_sprintf("%s%s", user_msg, US", PRDR Requested");
3940 smtp_user_msg(US"250",user_msg);
3942 smtp_delay_rcpt = smtp_rlr_base;
3943 recipients_discarded = (rc == DISCARD);
3944 was_rej_mail = FALSE;
3948 done = smtp_handle_acl_fail(ACL_WHERE_MAIL, rc, user_msg, log_msg);
3949 sender_address = NULL;
3954 /* The RCPT command requires an address as an operand. There may be any
3955 number of RCPT commands, specifying multiple recipients. We build them all
3956 into a data structure. The start/end values given by parse_extract_address
3957 are not used, as we keep only the extracted address. */
3962 was_rcpt = rcpt_in_progress = TRUE;
3964 /* There must be a sender address; if the sender was rejected and
3965 pipelining was advertised, we assume the client was pipelining, and do not
3966 count this as a protocol error. Reset was_rej_mail so that further RCPTs
3967 get the same treatment. */
3969 if (sender_address == NULL)
3971 if (pipelining_advertised && last_was_rej_mail)
3973 smtp_printf("503 sender not yet given\r\n");
3974 was_rej_mail = TRUE;
3978 done = synprot_error(L_smtp_protocol_error, 503, NULL,
3979 US"sender not yet given");
3980 was_rcpt = FALSE; /* Not a valid RCPT */
3986 /* Check for an operand */
3988 if (smtp_cmd_data[0] == 0)
3990 done = synprot_error(L_smtp_syntax_error, 501, NULL,
3991 US"RCPT must have an address operand");
3996 /* Apply SMTP rewriting then extract the working address. Don't allow "<>"
3997 as a recipient address */
3999 recipient = ((rewrite_existflags & rewrite_smtp) != 0)?
4000 rewrite_one(smtp_cmd_data, rewrite_smtp, NULL, FALSE, US"",
4001 global_rewrite_rules) : smtp_cmd_data;
4003 /* rfc821_domains = TRUE; << no longer needed */
4004 recipient = parse_extract_address(recipient, &errmess, &start, &end,
4005 &recipient_domain, FALSE);
4006 /* rfc821_domains = FALSE; << no longer needed */
4008 if (recipient == NULL)
4010 done = synprot_error(L_smtp_syntax_error, 501, smtp_cmd_data, errmess);
4015 /* If the recipient address is unqualified, reject it, unless this is a
4016 locally generated message. However, unqualified addresses are permitted
4017 from a configured list of hosts and nets - typically when behaving as
4018 MUAs rather than MTAs. Sad that SMTP is used for both types of traffic,
4019 really. The flag is set at the start of the SMTP connection.
4021 RFC 1123 talks about supporting "the reserved mailbox postmaster"; I always
4022 assumed this meant "reserved local part", but the revision of RFC 821 and
4023 friends now makes it absolutely clear that it means *mailbox*. Consequently
4024 we must always qualify this address, regardless. */
4026 if (recipient_domain == 0)
4028 if (allow_unqualified_recipient ||
4029 strcmpic(recipient, US"postmaster") == 0)
4031 DEBUG(D_receive) debug_printf("unqualified address %s accepted\n",
4033 recipient_domain = Ustrlen(recipient) + 1;
4034 recipient = rewrite_address_qualify(recipient, TRUE);
4039 smtp_printf("501 %s: recipient address must contain a domain\r\n",
4041 log_write(L_smtp_syntax_error,
4042 LOG_MAIN|LOG_REJECT, "unqualified recipient rejected: "
4043 "<%s> %s%s", recipient, host_and_ident(TRUE),
4049 /* Check maximum allowed */
4051 if (rcpt_count > recipients_max && recipients_max > 0)
4053 if (recipients_max_reject)
4056 smtp_printf("552 too many recipients\r\n");
4058 log_write(0, LOG_MAIN|LOG_REJECT, "too many recipients: message "
4059 "rejected: sender=<%s> %s", sender_address, host_and_ident(TRUE));
4064 smtp_printf("452 too many recipients\r\n");
4066 log_write(0, LOG_MAIN|LOG_REJECT, "too many recipients: excess "
4067 "temporarily rejected: sender=<%s> %s", sender_address,
4068 host_and_ident(TRUE));
4075 /* If we have passed the threshold for rate limiting, apply the current
4076 delay, and update it for next time, provided this is a limited host. */
4078 if (rcpt_count > smtp_rlr_threshold &&
4079 verify_check_host(&smtp_ratelimit_hosts) == OK)
4081 DEBUG(D_receive) debug_printf("rate limit RCPT: delay %.3g sec\n",
4082 smtp_delay_rcpt/1000.0);
4083 millisleep((int)smtp_delay_rcpt);
4084 smtp_delay_rcpt *= smtp_rlr_factor;
4085 if (smtp_delay_rcpt > (double)smtp_rlr_limit)
4086 smtp_delay_rcpt = (double)smtp_rlr_limit;
4089 /* If the MAIL ACL discarded all the recipients, we bypass ACL checking
4090 for them. Otherwise, check the access control list for this recipient. As
4091 there may be a delay in this, re-check for a synchronization error
4092 afterwards, unless pipelining was advertised. */
4094 if (recipients_discarded) rc = DISCARD; else
4096 rc = acl_check(ACL_WHERE_RCPT, recipient, acl_smtp_rcpt, &user_msg,
4098 if (rc == OK && !pipelining_advertised && !check_sync())
4102 /* The ACL was happy */
4106 if (user_msg == NULL) smtp_printf("250 Accepted\r\n");
4107 else smtp_user_msg(US"250", user_msg);
4108 receive_add_recipient(recipient, -1);
4111 /* The recipient was discarded */
4113 else if (rc == DISCARD)
4115 if (user_msg == NULL) smtp_printf("250 Accepted\r\n");
4116 else smtp_user_msg(US"250", user_msg);
4119 log_write(0, LOG_MAIN|LOG_REJECT, "%s F=<%s> rejected RCPT %s: "
4120 "discarded by %s ACL%s%s", host_and_ident(TRUE),
4121 (sender_address_unrewritten != NULL)?
4122 sender_address_unrewritten : sender_address,
4123 smtp_cmd_argument, recipients_discarded? "MAIL" : "RCPT",
4124 (log_msg == NULL)? US"" : US": ",
4125 (log_msg == NULL)? US"" : log_msg);
4128 /* Either the ACL failed the address, or it was deferred. */
4132 if (rc == FAIL) rcpt_fail_count++; else rcpt_defer_count++;
4133 done = smtp_handle_acl_fail(ACL_WHERE_RCPT, rc, user_msg, log_msg);
4138 /* The DATA command is legal only if it follows successful MAIL FROM
4139 and RCPT TO commands. However, if pipelining is advertised, a bad DATA is
4140 not counted as a protocol error if it follows RCPT (which must have been
4141 rejected if there are no recipients.) This function is complete when a
4142 valid DATA command is encountered.
4144 Note concerning the code used: RFC 2821 says this:
4146 - If there was no MAIL, or no RCPT, command, or all such commands
4147 were rejected, the server MAY return a "command out of sequence"
4148 (503) or "no valid recipients" (554) reply in response to the
4151 The example in the pipelining RFC 2920 uses 554, but I use 503 here
4152 because it is the same whether pipelining is in use or not.
4154 If all the RCPT commands that precede DATA provoked the same error message
4155 (often indicating some kind of system error), it is helpful to include it
4156 with the DATA rejection (an idea suggested by Tony Finch). */
4160 if (!discarded && recipients_count <= 0)
4162 if (rcpt_smtp_response_same && rcpt_smtp_response != NULL)
4164 uschar *code = US"503";
4165 int len = Ustrlen(rcpt_smtp_response);
4166 smtp_respond(code, 3, FALSE, US"All RCPT commands were rejected with "
4168 /* Responses from smtp_printf() will have \r\n on the end */
4169 if (len > 2 && rcpt_smtp_response[len-2] == '\r')
4170 rcpt_smtp_response[len-2] = 0;
4171 smtp_respond(code, 3, FALSE, rcpt_smtp_response);
4173 if (pipelining_advertised && last_was_rcpt)
4174 smtp_printf("503 Valid RCPT command must precede DATA\r\n");
4176 done = synprot_error(L_smtp_protocol_error, 503, NULL,
4177 US"valid RCPT command must precede DATA");
4181 if (toomany && recipients_max_reject)
4183 sender_address = NULL; /* This will allow a new MAIL without RSET */
4184 sender_address_unrewritten = NULL;
4185 smtp_printf("554 Too many recipients\r\n");
4189 /* If there is an ACL, re-check the synchronization afterwards, since the
4190 ACL may have delayed. To handle cutthrough delivery enforce a dummy call
4191 to get the DATA command sent. */
4193 if (acl_smtp_predata == NULL && cutthrough_fd < 0) rc = OK; else
4195 uschar * acl= acl_smtp_predata ? acl_smtp_predata : US"accept";
4196 enable_dollar_recipients = TRUE;
4197 rc = acl_check(ACL_WHERE_PREDATA, NULL, acl, &user_msg,
4199 enable_dollar_recipients = FALSE;
4200 if (rc == OK && !check_sync()) goto SYNC_FAILURE;
4207 if (user_msg == NULL)
4208 smtp_printf("%s Enter message, ending with \".\" on a line by itself\r\n", code);
4209 else smtp_user_msg(code, user_msg);
4211 message_ended = END_NOTENDED; /* Indicate in middle of data */
4214 /* Either the ACL failed the address, or it was deferred. */
4217 done = smtp_handle_acl_fail(ACL_WHERE_PREDATA, rc, user_msg, log_msg);
4223 rc = acl_check(ACL_WHERE_VRFY, NULL, acl_smtp_vrfy, &user_msg, &log_msg);
4225 done = smtp_handle_acl_fail(ACL_WHERE_VRFY, rc, user_msg, log_msg);
4231 /* rfc821_domains = TRUE; << no longer needed */
4232 address = parse_extract_address(smtp_cmd_data, &errmess, &start, &end,
4233 &recipient_domain, FALSE);
4234 /* rfc821_domains = FALSE; << no longer needed */
4236 if (address == NULL)
4237 s = string_sprintf("501 %s", errmess);
4240 address_item *addr = deliver_make_addr(address, FALSE);
4241 switch(verify_address(addr, NULL, vopt_is_recipient | vopt_qualify, -1,
4242 -1, -1, NULL, NULL, NULL))
4245 s = string_sprintf("250 <%s> is deliverable", address);
4249 s = (addr->user_message != NULL)?
4250 string_sprintf("451 <%s> %s", address, addr->user_message) :
4251 string_sprintf("451 Cannot resolve <%s> at this time", address);
4255 s = (addr->user_message != NULL)?
4256 string_sprintf("550 <%s> %s", address, addr->user_message) :
4257 string_sprintf("550 <%s> is not deliverable", address);
4258 log_write(0, LOG_MAIN, "VRFY failed for %s %s",
4259 smtp_cmd_argument, host_and_ident(TRUE));
4264 smtp_printf("%s\r\n", s);
4271 rc = acl_check(ACL_WHERE_EXPN, NULL, acl_smtp_expn, &user_msg, &log_msg);
4273 done = smtp_handle_acl_fail(ACL_WHERE_EXPN, rc, user_msg, log_msg);
4276 BOOL save_log_testing_mode = log_testing_mode;
4277 address_test_mode = log_testing_mode = TRUE;
4278 (void) verify_address(deliver_make_addr(smtp_cmd_data, FALSE),
4279 smtp_out, vopt_is_recipient | vopt_qualify | vopt_expn, -1, -1, -1,
4281 address_test_mode = FALSE;
4282 log_testing_mode = save_log_testing_mode; /* true for -bh */
4291 if (!tls_advertised)
4293 done = synprot_error(L_smtp_protocol_error, 503, NULL,
4294 US"STARTTLS command used when not advertised");
4298 /* Apply an ACL check if one is defined */
4300 if (acl_smtp_starttls != NULL)
4302 rc = acl_check(ACL_WHERE_STARTTLS, NULL, acl_smtp_starttls, &user_msg,
4306 done = smtp_handle_acl_fail(ACL_WHERE_STARTTLS, rc, user_msg, log_msg);
4311 /* RFC 2487 is not clear on when this command may be sent, though it
4312 does state that all information previously obtained from the client
4313 must be discarded if a TLS session is started. It seems reasonble to
4314 do an implied RSET when STARTTLS is received. */
4316 incomplete_transaction_log(US"STARTTLS");
4317 smtp_reset(reset_point);
4319 cmd_list[CMD_LIST_STARTTLS].is_mail_cmd = FALSE;
4321 /* There's an attack where more data is read in past the STARTTLS command
4322 before TLS is negotiated, then assumed to be part of the secure session
4323 when used afterwards; we use segregated input buffers, so are not
4324 vulnerable, but we want to note when it happens and, for sheer paranoia,
4325 ensure that the buffer is "wiped".
4326 Pipelining sync checks will normally have protected us too, unless disabled
4327 by configuration. */
4329 if (receive_smtp_buffered())
4332 debug_printf("Non-empty input buffer after STARTTLS; naive attack?");
4333 if (tls_in.active < 0)
4334 smtp_inend = smtp_inptr = smtp_inbuffer;
4335 /* and if TLS is already active, tls_server_start() should fail */
4338 /* There is nothing we value in the input buffer and if TLS is succesfully
4339 negotiated, we won't use this buffer again; if TLS fails, we'll just read
4340 fresh content into it. The buffer contains arbitrary content from an
4341 untrusted remote source; eg: NOOP <shellcode>\r\nSTARTTLS\r\n
4342 It seems safest to just wipe away the content rather than leave it as a
4343 target to jump to. */
4345 memset(smtp_inbuffer, 0, in_buffer_size);
4347 /* Attempt to start up a TLS session, and if successful, discard all
4348 knowledge that was obtained previously. At least, that's what the RFC says,
4349 and that's what happens by default. However, in order to work round YAEB,
4350 there is an option to remember the esmtp state. Sigh.
4352 We must allow for an extra EHLO command and an extra AUTH command after
4353 STARTTLS that don't add to the nonmail command count. */
4355 if ((rc = tls_server_start(tls_require_ciphers)) == OK)
4357 if (!tls_remember_esmtp)
4358 helo_seen = esmtp = auth_advertised = pipelining_advertised = FALSE;
4359 cmd_list[CMD_LIST_EHLO].is_mail_cmd = TRUE;
4360 cmd_list[CMD_LIST_AUTH].is_mail_cmd = TRUE;
4361 if (sender_helo_name != NULL)
4363 store_free(sender_helo_name);
4364 sender_helo_name = NULL;
4365 host_build_sender_fullhost(); /* Rebuild */
4366 set_process_info("handling incoming TLS connection from %s",
4367 host_and_ident(FALSE));
4369 received_protocol = (esmtp?
4370 protocols[pextend + pcrpted +
4371 ((sender_host_authenticated != NULL)? pauthed : 0)]
4373 protocols[pnormal + pcrpted])
4375 ((sender_host_address != NULL)? pnlocal : 0);
4377 sender_host_authenticated = NULL;
4378 authenticated_id = NULL;
4379 sync_cmd_limit = NON_SYNC_CMD_NON_PIPELINING;
4380 DEBUG(D_tls) debug_printf("TLS active\n");
4381 break; /* Successful STARTTLS */
4384 /* Some local configuration problem was discovered before actually trying
4385 to do a TLS handshake; give a temporary error. */
4387 else if (rc == DEFER)
4389 smtp_printf("454 TLS currently unavailable\r\n");
4393 /* Hard failure. Reject everything except QUIT or closed connection. One
4394 cause for failure is a nested STARTTLS, in which case tls_in.active remains
4395 set, but we must still reject all incoming commands. */
4397 DEBUG(D_tls) debug_printf("TLS failed to start\n");
4400 switch(smtp_read_command(FALSE))
4403 log_write(L_smtp_connection, LOG_MAIN, "%s closed by EOF",
4404 smtp_get_connection_info());
4405 smtp_notquit_exit(US"tls-failed", NULL, NULL);
4409 /* It is perhaps arguable as to which exit ACL should be called here,
4410 but as it is probably a situation that almost never arises, it
4411 probably doesn't matter. We choose to call the real QUIT ACL, which in
4412 some sense is perhaps "right". */
4416 if (acl_smtp_quit != NULL)
4418 rc = acl_check(ACL_WHERE_QUIT, NULL, acl_smtp_quit, &user_msg,
4421 log_write(0, LOG_MAIN|LOG_PANIC, "ACL for QUIT returned ERROR: %s",
4424 if (user_msg == NULL)
4425 smtp_printf("221 %s closing connection\r\n", smtp_active_hostname);
4427 smtp_respond(US"221", 3, TRUE, user_msg);
4428 log_write(L_smtp_connection, LOG_MAIN, "%s closed by QUIT",
4429 smtp_get_connection_info());
4434 smtp_printf("554 Security failure\r\n");
4438 tls_close(TRUE, TRUE);
4443 /* The ACL for QUIT is provided for gathering statistical information or
4444 similar; it does not affect the response code, but it can supply a custom
4449 incomplete_transaction_log(US"QUIT");
4450 if (acl_smtp_quit != NULL)
4452 rc = acl_check(ACL_WHERE_QUIT, NULL, acl_smtp_quit, &user_msg, &log_msg);
4454 log_write(0, LOG_MAIN|LOG_PANIC, "ACL for QUIT returned ERROR: %s",
4457 if (user_msg == NULL)
4458 smtp_printf("221 %s closing connection\r\n", smtp_active_hostname);
4460 smtp_respond(US"221", 3, TRUE, user_msg);
4463 tls_close(TRUE, TRUE);
4467 log_write(L_smtp_connection, LOG_MAIN, "%s closed by QUIT",
4468 smtp_get_connection_info());
4474 incomplete_transaction_log(US"RSET");
4475 smtp_reset(reset_point);
4477 smtp_printf("250 Reset OK\r\n");
4478 cmd_list[CMD_LIST_RSET].is_mail_cmd = FALSE;
4484 smtp_printf("250 OK\r\n");
4488 /* Show ETRN/EXPN/VRFY if there's an ACL for checking hosts; if actually
4489 used, a check will be done for permitted hosts. Show STARTTLS only if not
4490 already in a TLS session and if it would be advertised in the EHLO
4495 smtp_printf("214-Commands supported:\r\n");
4499 Ustrcat(buffer, " AUTH");
4501 if (tls_in.active < 0 &&
4502 verify_check_host(&tls_advertise_hosts) != FAIL)
4503 Ustrcat(buffer, " STARTTLS");
4505 Ustrcat(buffer, " HELO EHLO MAIL RCPT DATA");
4506 Ustrcat(buffer, " NOOP QUIT RSET HELP");
4507 if (acl_smtp_etrn != NULL) Ustrcat(buffer, " ETRN");
4508 if (acl_smtp_expn != NULL) Ustrcat(buffer, " EXPN");
4509 if (acl_smtp_vrfy != NULL) Ustrcat(buffer, " VRFY");
4510 smtp_printf("214%s\r\n", buffer);
4516 incomplete_transaction_log(US"connection lost");
4517 smtp_notquit_exit(US"connection-lost", US"421",
4518 US"%s lost input connection", smtp_active_hostname);
4520 /* Don't log by default unless in the middle of a message, as some mailers
4521 just drop the call rather than sending QUIT, and it clutters up the logs.
4524 if (sender_address != NULL || recipients_count > 0)
4525 log_write(L_lost_incoming_connection,
4527 "unexpected %s while reading SMTP command from %s%s",
4528 sender_host_unknown? "EOF" : "disconnection",
4529 host_and_ident(FALSE), smtp_read_error);
4531 else log_write(L_smtp_connection, LOG_MAIN, "%s lost%s",
4532 smtp_get_connection_info(), smtp_read_error);
4540 if (sender_address != NULL)
4542 done = synprot_error(L_smtp_protocol_error, 503, NULL,
4543 US"ETRN is not permitted inside a transaction");
4547 log_write(L_etrn, LOG_MAIN, "ETRN %s received from %s", smtp_cmd_argument,
4548 host_and_ident(FALSE));
4550 rc = acl_check(ACL_WHERE_ETRN, NULL, acl_smtp_etrn, &user_msg, &log_msg);
4553 done = smtp_handle_acl_fail(ACL_WHERE_ETRN, rc, user_msg, log_msg);
4557 /* Compute the serialization key for this command. */
4559 etrn_serialize_key = string_sprintf("etrn-%s\n", smtp_cmd_data);
4561 /* If a command has been specified for running as a result of ETRN, we
4562 permit any argument to ETRN. If not, only the # standard form is permitted,
4563 since that is strictly the only kind of ETRN that can be implemented
4564 according to the RFC. */
4566 if (smtp_etrn_command != NULL)
4570 etrn_command = smtp_etrn_command;
4571 deliver_domain = smtp_cmd_data;
4572 rc = transport_set_up_command(&argv, smtp_etrn_command, TRUE, 0, NULL,
4573 US"ETRN processing", &error);
4574 deliver_domain = NULL;
4577 log_write(0, LOG_MAIN|LOG_PANIC, "failed to set up ETRN command: %s",
4579 smtp_printf("458 Internal failure\r\n");
4584 /* Else set up to call Exim with the -R option. */
4588 if (*smtp_cmd_data++ != '#')
4590 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4591 US"argument must begin with #");
4594 etrn_command = US"exim -R";
4595 argv = child_exec_exim(CEE_RETURN_ARGV, TRUE, NULL, TRUE, 2, US"-R",
4599 /* If we are host-testing, don't actually do anything. */
4605 debug_printf("ETRN command is: %s\n", etrn_command);
4606 debug_printf("ETRN command execution skipped\n");
4608 if (user_msg == NULL) smtp_printf("250 OK\r\n");
4609 else smtp_user_msg(US"250", user_msg);
4614 /* If ETRN queue runs are to be serialized, check the database to
4615 ensure one isn't already running. */
4617 if (smtp_etrn_serialize && !enq_start(etrn_serialize_key))
4619 smtp_printf("458 Already processing %s\r\n", smtp_cmd_data);
4623 /* Fork a child process and run the command. We don't want to have to
4624 wait for the process at any point, so set SIGCHLD to SIG_IGN before
4625 forking. It should be set that way anyway for external incoming SMTP,
4626 but we save and restore to be tidy. If serialization is required, we
4627 actually run the command in yet another process, so we can wait for it
4628 to complete and then remove the serialization lock. */
4630 oldsignal = signal(SIGCHLD, SIG_IGN);
4632 if ((pid = fork()) == 0)
4634 smtp_input = FALSE; /* This process is not associated with the */
4635 (void)fclose(smtp_in); /* SMTP call any more. */
4636 (void)fclose(smtp_out);
4638 signal(SIGCHLD, SIG_DFL); /* Want to catch child */
4640 /* If not serializing, do the exec right away. Otherwise, fork down
4641 into another process. */
4643 if (!smtp_etrn_serialize || (pid = fork()) == 0)
4645 DEBUG(D_exec) debug_print_argv(argv);
4646 exim_nullstd(); /* Ensure std{in,out,err} exist */
4647 execv(CS argv[0], (char *const *)argv);
4648 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "exec of \"%s\" (ETRN) failed: %s",
4649 etrn_command, strerror(errno));
4650 _exit(EXIT_FAILURE); /* paranoia */
4653 /* Obey this if smtp_serialize and the 2nd fork yielded non-zero. That
4654 is, we are in the first subprocess, after forking again. All we can do
4655 for a failing fork is to log it. Otherwise, wait for the 2nd process to
4656 complete, before removing the serialization. */
4659 log_write(0, LOG_MAIN|LOG_PANIC, "2nd fork for serialized ETRN "
4660 "failed: %s", strerror(errno));
4664 DEBUG(D_any) debug_printf("waiting for serialized ETRN process %d\n",
4666 (void)wait(&status);
4667 DEBUG(D_any) debug_printf("serialized ETRN process %d ended\n",
4671 enq_end(etrn_serialize_key);
4672 _exit(EXIT_SUCCESS);
4675 /* Back in the top level SMTP process. Check that we started a subprocess
4676 and restore the signal state. */
4680 log_write(0, LOG_MAIN|LOG_PANIC, "fork of process for ETRN failed: %s",
4682 smtp_printf("458 Unable to fork process\r\n");
4683 if (smtp_etrn_serialize) enq_end(etrn_serialize_key);
4687 if (user_msg == NULL) smtp_printf("250 OK\r\n");
4688 else smtp_user_msg(US"250", user_msg);
4691 signal(SIGCHLD, oldsignal);
4696 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4697 US"unexpected argument data");
4701 /* This currently happens only for NULLs, but could be extended. */
4704 done = synprot_error(L_smtp_syntax_error, 0, NULL, /* Just logs */
4705 US"NULL character(s) present (shown as '?')");
4706 smtp_printf("501 NULL characters are not allowed in SMTP commands\r\n");
4712 if (smtp_inend >= smtp_inbuffer + in_buffer_size)
4713 smtp_inend = smtp_inbuffer + in_buffer_size - 1;
4714 c = smtp_inend - smtp_inptr;
4715 if (c > 150) c = 150;
4717 incomplete_transaction_log(US"sync failure");
4718 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP protocol synchronization error "
4719 "(next input sent too soon: pipelining was%s advertised): "
4720 "rejected \"%s\" %s next input=\"%s\"",
4721 pipelining_advertised? "" : " not",
4722 smtp_cmd_buffer, host_and_ident(TRUE),
4723 string_printing(smtp_inptr));
4724 smtp_notquit_exit(US"synchronization-error", US"554",
4725 US"SMTP synchronization error");
4726 done = 1; /* Pretend eof - drops connection */
4730 case TOO_MANY_NONMAIL_CMD:
4731 s = smtp_cmd_buffer;
4732 while (*s != 0 && !isspace(*s)) s++;
4733 incomplete_transaction_log(US"too many non-mail commands");
4734 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
4735 "nonmail commands (last was \"%.*s\")", host_and_ident(FALSE),
4736 (int)(s - smtp_cmd_buffer), smtp_cmd_buffer);
4737 smtp_notquit_exit(US"bad-commands", US"554", US"Too many nonmail commands");
4738 done = 1; /* Pretend eof - drops connection */
4741 #ifdef EXPERIMENTAL_PROXY
4742 case PROXY_FAIL_IGNORE_CMD:
4743 smtp_printf("503 Command refused, required Proxy negotiation failed\r\n");
4748 if (unknown_command_count++ >= smtp_max_unknown_commands)
4750 log_write(L_smtp_syntax_error, LOG_MAIN,
4751 "SMTP syntax error in \"%s\" %s %s",
4752 string_printing(smtp_cmd_buffer), host_and_ident(TRUE),
4753 US"unrecognized command");
4754 incomplete_transaction_log(US"unrecognized command");
4755 smtp_notquit_exit(US"bad-commands", US"500",
4756 US"Too many unrecognized commands");
4758 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
4759 "unrecognized commands (last was \"%s\")", host_and_ident(FALSE),
4763 done = synprot_error(L_smtp_syntax_error, 500, NULL,
4764 US"unrecognized command");
4768 /* This label is used by goto's inside loops that want to break out to
4769 the end of the command-processing loop. */
4772 last_was_rej_mail = was_rej_mail; /* Remember some last commands for */
4773 last_was_rcpt = was_rcpt; /* protocol error handling */
4777 return done - 2; /* Convert yield values */
4780 /* End of smtp_in.c */