1 /*************************************************
2 * Exim - an Internet mail transport agent *
3 *************************************************/
5 /* Copyright (c) University of Cambridge 1995 - 2016 */
6 /* See the file NOTICE for conditions of use and distribution. */
8 /* Functions for handling an incoming SMTP call. */
15 /* Initialize for TCP wrappers if so configured. It appears that the macro
16 HAVE_IPV6 is used in some versions of the tcpd.h header, so we unset it before
17 including that header, and restore its value afterwards. */
19 #ifdef USE_TCP_WRAPPERS
22 #define EXIM_HAVE_IPV6
28 #define HAVE_IPV6 TRUE
31 int allow_severity = LOG_INFO;
32 int deny_severity = LOG_NOTICE;
33 uschar *tcp_wrappers_name;
37 /* Size of buffer for reading SMTP commands. We used to use 512, as defined
38 by RFC 821. However, RFC 1869 specifies that this must be increased for SMTP
39 commands that accept arguments, and this in particular applies to AUTH, where
40 the data can be quite long. More recently this value was 2048 in Exim;
41 however, RFC 4954 (circa 2007) recommends 12288 bytes to handle AUTH. Clients
42 such as Thunderbird will send an AUTH with an initial-response for GSSAPI.
43 The maximum size of a Kerberos ticket under Windows 2003 is 12000 bytes, and
44 we need room to handle large base64-encoded AUTHs for GSSAPI.
47 #define smtp_cmd_buffer_size 16384
49 /* Size of buffer for reading SMTP incoming packets */
51 #define in_buffer_size 8192
53 /* Structure for SMTP command list */
60 short int is_mail_cmd;
63 /* Codes for identifying commands. We order them so that those that come first
64 are those for which synchronization is always required. Checking this can help
68 /* These commands are required to be synchronized, i.e. to be the last in a
69 block of commands when pipelining. */
71 HELO_CMD, EHLO_CMD, DATA_CMD, /* These are listed in the pipelining */
72 VRFY_CMD, EXPN_CMD, NOOP_CMD, /* RFC as requiring synchronization */
73 ETRN_CMD, /* This by analogy with TURN from the RFC */
74 STARTTLS_CMD, /* Required by the STARTTLS RFC */
75 TLS_AUTH_CMD, /* auto-command at start of SSL */
76 BDAT_CMD, /* Implied by RFC3030 "After all MAIL and..." */
78 /* This is a dummy to identify the non-sync commands when pipelining */
80 NON_SYNC_CMD_PIPELINING,
82 /* These commands need not be synchronized when pipelining */
84 MAIL_CMD, RCPT_CMD, RSET_CMD,
86 /* This is a dummy to identify the non-sync commands when not pipelining */
88 NON_SYNC_CMD_NON_PIPELINING,
90 /* I have been unable to find a statement about the use of pipelining
91 with AUTH, so to be on the safe side it is here, though I kind of feel
92 it should be up there with the synchronized commands. */
96 /* I'm not sure about these, but I don't think they matter. */
101 PROXY_FAIL_IGNORE_CMD,
104 /* These are specials that don't correspond to actual commands */
106 EOF_CMD, OTHER_CMD, BADARG_CMD, BADCHAR_CMD, BADSYN_CMD,
107 TOO_MANY_NONMAIL_CMD };
110 /* This is a convenience macro for adding the identity of an SMTP command
111 to the circular buffer that holds a list of the last n received. */
114 smtp_connection_had[smtp_ch_index++] = n; \
115 if (smtp_ch_index >= SMTP_HBUFF_SIZE) smtp_ch_index = 0
118 /*************************************************
119 * Local static variables *
120 *************************************************/
122 static auth_instance *authenticated_by;
123 static BOOL auth_advertised;
125 static BOOL tls_advertised;
127 static BOOL dsn_advertised;
129 static BOOL helo_required = FALSE;
130 static BOOL helo_verify = FALSE;
131 static BOOL helo_seen;
132 static BOOL helo_accept_junk;
133 static BOOL count_nonmail;
134 static BOOL pipelining_advertised;
135 static BOOL rcpt_smtp_response_same;
136 static BOOL rcpt_in_progress;
137 static int nonmail_command_count;
138 static BOOL smtp_exit_function_called = 0;
140 static BOOL smtputf8_advertised;
142 static int synprot_error_count;
143 static int unknown_command_count;
144 static int sync_cmd_limit;
145 static int smtp_write_error = 0;
147 static uschar *rcpt_smtp_response;
148 static uschar *smtp_data_buffer;
149 static uschar *smtp_cmd_data;
151 /* We need to know the position of RSET, HELO, EHLO, AUTH, and STARTTLS. Their
152 final fields of all except AUTH are forced TRUE at the start of a new message
153 setup, to allow one of each between messages that is not counted as a nonmail
154 command. (In fact, only one of HELO/EHLO is not counted.) Also, we have to
155 allow a new EHLO after starting up TLS.
157 AUTH is "falsely" labelled as a mail command initially, so that it doesn't get
158 counted. However, the flag is changed when AUTH is received, so that multiple
159 failing AUTHs will eventually hit the limit. After a successful AUTH, another
160 AUTH is already forbidden. After a TLS session is started, AUTH's flag is again
161 forced TRUE, to allow for the re-authentication that can happen at that point.
163 QUIT is also "falsely" labelled as a mail command so that it doesn't up the
164 count of non-mail commands and possibly provoke an error.
166 tls_auth is a pseudo-command, never expected in input. It is activated
167 on TLS startup and looks for a tls authenticator. */
169 static smtp_cmd_list cmd_list[] = {
170 /* name len cmd has_arg is_mail_cmd */
172 { "rset", sizeof("rset")-1, RSET_CMD, FALSE, FALSE }, /* First */
173 { "helo", sizeof("helo")-1, HELO_CMD, TRUE, FALSE },
174 { "ehlo", sizeof("ehlo")-1, EHLO_CMD, TRUE, FALSE },
175 { "auth", sizeof("auth")-1, AUTH_CMD, TRUE, TRUE },
177 { "starttls", sizeof("starttls")-1, STARTTLS_CMD, FALSE, FALSE },
178 { "tls_auth", 0, TLS_AUTH_CMD, FALSE, TRUE },
181 /* If you change anything above here, also fix the definitions below. */
183 { "mail from:", sizeof("mail from:")-1, MAIL_CMD, TRUE, TRUE },
184 { "rcpt to:", sizeof("rcpt to:")-1, RCPT_CMD, TRUE, TRUE },
185 { "data", sizeof("data")-1, DATA_CMD, FALSE, TRUE },
186 { "bdat", sizeof("bdat")-1, BDAT_CMD, TRUE, TRUE },
187 { "quit", sizeof("quit")-1, QUIT_CMD, FALSE, TRUE },
188 { "noop", sizeof("noop")-1, NOOP_CMD, TRUE, FALSE },
189 { "etrn", sizeof("etrn")-1, ETRN_CMD, TRUE, FALSE },
190 { "vrfy", sizeof("vrfy")-1, VRFY_CMD, TRUE, FALSE },
191 { "expn", sizeof("expn")-1, EXPN_CMD, TRUE, FALSE },
192 { "help", sizeof("help")-1, HELP_CMD, TRUE, FALSE }
195 static smtp_cmd_list *cmd_list_end =
196 cmd_list + sizeof(cmd_list)/sizeof(smtp_cmd_list);
198 #define CMD_LIST_RSET 0
199 #define CMD_LIST_HELO 1
200 #define CMD_LIST_EHLO 2
201 #define CMD_LIST_AUTH 3
202 #define CMD_LIST_STARTTLS 4
203 #define CMD_LIST_TLS_AUTH 5
205 /* This list of names is used for performing the smtp_no_mail logging action.
206 It must be kept in step with the SCH_xxx enumerations. */
208 static uschar *smtp_names[] =
210 US"NONE", US"AUTH", US"DATA", US"BDAT", US"EHLO", US"ETRN", US"EXPN",
211 US"HELO", US"HELP", US"MAIL", US"NOOP", US"QUIT", US"RCPT", US"RSET",
212 US"STARTTLS", US"VRFY" };
214 static uschar *protocols_local[] = {
215 US"local-smtp", /* HELO */
216 US"local-smtps", /* The rare case EHLO->STARTTLS->HELO */
217 US"local-esmtp", /* EHLO */
218 US"local-esmtps", /* EHLO->STARTTLS->EHLO */
219 US"local-esmtpa", /* EHLO->AUTH */
220 US"local-esmtpsa" /* EHLO->STARTTLS->EHLO->AUTH */
222 static uschar *protocols[] = {
224 US"smtps", /* The rare case EHLO->STARTTLS->HELO */
225 US"esmtp", /* EHLO */
226 US"esmtps", /* EHLO->STARTTLS->EHLO */
227 US"esmtpa", /* EHLO->AUTH */
228 US"esmtpsa" /* EHLO->STARTTLS->EHLO->AUTH */
233 #define pcrpted 1 /* added to pextend or pnormal */
234 #define pauthed 2 /* added to pextend */
236 /* Sanity check and validate optional args to MAIL FROM: envelope */
239 ENV_MAIL_OPT_SIZE, ENV_MAIL_OPT_BODY, ENV_MAIL_OPT_AUTH,
243 ENV_MAIL_OPT_RET, ENV_MAIL_OPT_ENVID,
249 uschar * name; /* option requested during MAIL cmd */
250 int value; /* enum type */
251 BOOL need_value; /* TRUE requires value (name=value pair format)
252 FALSE is a singleton */
254 static env_mail_type_t env_mail_type_list[] = {
255 { US"SIZE", ENV_MAIL_OPT_SIZE, TRUE },
256 { US"BODY", ENV_MAIL_OPT_BODY, TRUE },
257 { US"AUTH", ENV_MAIL_OPT_AUTH, TRUE },
259 { US"PRDR", ENV_MAIL_OPT_PRDR, FALSE },
261 { US"RET", ENV_MAIL_OPT_RET, TRUE },
262 { US"ENVID", ENV_MAIL_OPT_ENVID, TRUE },
264 { US"SMTPUTF8",ENV_MAIL_OPT_UTF8, FALSE }, /* rfc6531 */
266 /* keep this the last entry */
267 { US"NULL", ENV_MAIL_OPT_NULL, FALSE },
270 /* When reading SMTP from a remote host, we have to use our own versions of the
271 C input-reading functions, in order to be able to flush the SMTP output only
272 when about to read more data from the socket. This is the only way to get
273 optimal performance when the client is using pipelining. Flushing for every
274 command causes a separate packet and reply packet each time; saving all the
275 responses up (when pipelining) combines them into one packet and one response.
277 For simplicity, these functions are used for *all* SMTP input, not only when
278 receiving over a socket. However, after setting up a secure socket (SSL), input
279 is read via the OpenSSL library, and another set of functions is used instead
282 These functions are set in the receive_getc etc. variables and called with the
283 same interface as the C functions. However, since there can only ever be
284 one incoming SMTP call, we just use a single buffer and flags. There is no need
285 to implement a complicated private FILE-like structure.*/
287 static uschar *smtp_inbuffer;
288 static uschar *smtp_inptr;
289 static uschar *smtp_inend;
290 static int smtp_had_eof;
291 static int smtp_had_error;
294 /* forward declarations */
295 int bdat_ungetc(int ch);
296 static int smtp_read_command(BOOL check_sync);
297 static int synprot_error(int type, int code, uschar *data, uschar *errmess);
298 static void smtp_quit_handler(uschar **, uschar **);
299 static void smtp_rset_handler(void);
301 /*************************************************
302 * SMTP version of getc() *
303 *************************************************/
305 /* This gets the next byte from the SMTP input buffer. If the buffer is empty,
306 it flushes the output, and refills the buffer, with a timeout. The signal
307 handler is set appropriately by the calling function. This function is not used
308 after a connection has negotated itself into an TLS/SSL state.
311 Returns: the next character or EOF
317 if (smtp_inptr >= smtp_inend)
321 if (smtp_receive_timeout > 0) alarm(smtp_receive_timeout);
322 rc = read(fileno(smtp_in), smtp_inbuffer, in_buffer_size);
327 /* Must put the error text in fixed store, because this might be during
328 header reading, where it releases unused store above the header. */
331 smtp_had_error = save_errno;
332 smtp_read_error = string_copy_malloc(
333 string_sprintf(" (error: %s)", strerror(save_errno)));
335 else smtp_had_eof = 1;
339 dkim_exim_verify_feed(smtp_inbuffer, rc);
341 smtp_inend = smtp_inbuffer + rc;
342 smtp_inptr = smtp_inbuffer;
344 return *smtp_inptr++;
349 /* Get a byte from the smtp input, in CHUNKING mode. Handle ack of the
350 previous BDAT chunk and getting new ones when we run out. Uses the
351 underlying smtp_getc or tls_getc both for that and for getting the
352 (buffered) data byte. EOD signals (an expected) no further data.
353 ERR signals a protocol error, and EOF a closed input stream.
355 Called from read_bdat_smtp() in receive.c for the message body, but also
356 by the headers read loop in receive_msg(); manipulates chunking_state
357 to handle the BDAT command/response.
358 Placed here due to the correlation with the above smtp_getc(), which it wraps,
359 and also by the need to do smtp command/response handling.
362 Returns: the next character or ERR, EOD or EOF
368 uschar * user_msg = NULL;
373 if (chunking_data_left-- > 0)
374 return lwr_receive_getc();
376 receive_getc = lwr_receive_getc;
377 receive_ungetc = lwr_receive_ungetc;
379 /* If not the last, ack the received chunk. The last response is delayed
380 until after the data ACL decides on it */
381 /*XXX find that "last response" and append the chunk size */
383 if (chunking_state == CHUNKING_LAST)
386 chunking_state = CHUNKING_OFFERED;
387 smtp_printf("250 %u byte chunk received\r\n", chunking_datasize);
389 /* Expect another BDAT cmd from input. RFC 3030 says nothing about
390 QUIT, RSET or NOOP but handling them seems obvious */
393 switch(smtp_read_command(TRUE))
396 (void) synprot_error(L_smtp_protocol_error, 503, NULL,
397 US"only BDAT permissible after non-LAST BDAT");
400 switch(smtp_read_command(TRUE))
402 case QUIT_CMD: smtp_quit_handler(&user_msg, &log_msg); /*FALLTHROUGH */
403 case EOF_CMD: return EOF;
404 case RSET_CMD: smtp_rset_handler(); return ERR;
405 default: if (synprot_error(L_smtp_protocol_error, 503, NULL,
406 US"only RSET accepted now") > 0)
408 goto repeat_until_rset;
412 smtp_quit_handler(&user_msg, &log_msg);
423 smtp_printf("250 OK\r\n");
430 if (sscanf(CS smtp_cmd_data, "%u %n", &chunking_datasize, &n) < 1)
432 (void) synprot_error(L_smtp_protocol_error, 501, NULL,
433 US"missing size for BDAT command");
436 chunking_state = strcmpic(smtp_cmd_data+n, US"LAST") == 0
437 ? CHUNKING_LAST : CHUNKING_ACTIVE;
438 chunking_data_left = chunking_datasize;
440 if (chunking_datasize == 0)
441 if (chunking_state == CHUNKING_LAST)
445 (void) synprot_error(L_smtp_protocol_error, 504, NULL,
446 US"zero size for BDAT command");
447 goto repeat_until_rset;
450 receive_getc = bdat_getc;
451 receive_ungetc = bdat_ungetc;
452 break; /* to top of main loop */
461 /*************************************************
462 * SMTP version of ungetc() *
463 *************************************************/
465 /* Puts a character back in the input buffer. Only ever
471 Returns: the character
485 chunking_data_left++;
486 return lwr_receive_ungetc(ch);
491 /*************************************************
492 * SMTP version of feof() *
493 *************************************************/
495 /* Tests for a previous EOF
498 Returns: non-zero if the eof flag is set
510 /*************************************************
511 * SMTP version of ferror() *
512 *************************************************/
514 /* Tests for a previous read error, and returns with errno
515 restored to what it was when the error was detected.
518 Returns: non-zero if the error flag is set
524 errno = smtp_had_error;
525 return smtp_had_error;
530 /*************************************************
531 * Test for characters in the SMTP buffer *
532 *************************************************/
534 /* Used at the end of a message
543 return smtp_inptr < smtp_inend;
548 /*************************************************
549 * Write formatted string to SMTP channel *
550 *************************************************/
552 /* This is a separate function so that we don't have to repeat everything for
553 TLS support or debugging. It is global so that the daemon and the
554 authentication functions can use it. It does not return any error indication,
555 because major problems such as dropped connections won't show up till an output
556 flush for non-TLS connections. The smtp_fflush() function is available for
557 checking that: for convenience, TLS output errors are remembered here so that
558 they are also picked up later by smtp_fflush().
562 ... optional arguments
568 smtp_printf(const char *format, ...)
572 va_start(ap, format);
573 smtp_vprintf(format, ap);
577 /* This is split off so that verify.c:respond_printf() can, in effect, call
578 smtp_printf(), bearing in mind that in C a vararg function can't directly
579 call another vararg function, only a function which accepts a va_list. */
582 smtp_vprintf(const char *format, va_list ap)
586 yield = string_vformat(big_buffer, big_buffer_size, format, ap);
590 void *reset_point = store_get(0);
591 uschar *msg_copy, *cr, *end;
592 msg_copy = string_copy(big_buffer);
593 end = msg_copy + Ustrlen(msg_copy);
594 while ((cr = Ustrchr(msg_copy, '\r')) != NULL) /* lose CRs */
595 memmove(cr, cr + 1, (end--) - cr);
596 debug_printf("SMTP>> %s", msg_copy);
597 store_reset(reset_point);
602 log_write(0, LOG_MAIN|LOG_PANIC, "string too large in smtp_printf()");
603 smtp_closedown(US"Unexpected error");
604 exim_exit(EXIT_FAILURE);
607 /* If this is the first output for a (non-batch) RCPT command, see if all RCPTs
608 have had the same. Note: this code is also present in smtp_respond(). It would
609 be tidier to have it only in one place, but when it was added, it was easier to
610 do it that way, so as not to have to mess with the code for the RCPT command,
611 which sometimes uses smtp_printf() and sometimes smtp_respond(). */
613 if (rcpt_in_progress)
615 if (rcpt_smtp_response == NULL)
616 rcpt_smtp_response = string_copy(big_buffer);
617 else if (rcpt_smtp_response_same &&
618 Ustrcmp(rcpt_smtp_response, big_buffer) != 0)
619 rcpt_smtp_response_same = FALSE;
620 rcpt_in_progress = FALSE;
623 /* Now write the string */
626 if (tls_in.active >= 0)
628 if (tls_write(TRUE, big_buffer, Ustrlen(big_buffer)) < 0)
629 smtp_write_error = -1;
634 if (fprintf(smtp_out, "%s", big_buffer) < 0) smtp_write_error = -1;
639 /*************************************************
640 * Flush SMTP out and check for error *
641 *************************************************/
643 /* This function isn't currently used within Exim (it detects errors when it
644 tries to read the next SMTP input), but is available for use in local_scan().
645 For non-TLS connections, it flushes the output and checks for errors. For
646 TLS-connections, it checks for a previously-detected TLS write error.
649 Returns: 0 for no error; -1 after an error
655 if (tls_in.active < 0 && fflush(smtp_out) != 0) smtp_write_error = -1;
656 return smtp_write_error;
661 /*************************************************
662 * SMTP command read timeout *
663 *************************************************/
665 /* Signal handler for timing out incoming SMTP commands. This attempts to
668 Argument: signal number (SIGALRM)
673 command_timeout_handler(int sig)
675 sig = sig; /* Keep picky compilers happy */
676 log_write(L_lost_incoming_connection,
677 LOG_MAIN, "SMTP command timeout on%s connection from %s",
678 (tls_in.active >= 0)? " TLS" : "",
679 host_and_ident(FALSE));
680 if (smtp_batched_input)
681 moan_smtp_batch(NULL, "421 SMTP command timeout"); /* Does not return */
682 smtp_notquit_exit(US"command-timeout", US"421",
683 US"%s: SMTP command timeout - closing connection", smtp_active_hostname);
684 exim_exit(EXIT_FAILURE);
689 /*************************************************
691 *************************************************/
693 /* Signal handler for handling SIGTERM. Again, try to finish tidily.
695 Argument: signal number (SIGTERM)
700 command_sigterm_handler(int sig)
702 sig = sig; /* Keep picky compilers happy */
703 log_write(0, LOG_MAIN, "%s closed after SIGTERM", smtp_get_connection_info());
704 if (smtp_batched_input)
705 moan_smtp_batch(NULL, "421 SIGTERM received"); /* Does not return */
706 smtp_notquit_exit(US"signal-exit", US"421",
707 US"%s: Service not available - closing connection", smtp_active_hostname);
708 exim_exit(EXIT_FAILURE);
715 /*************************************************
716 * Restore socket timeout to previous value *
717 *************************************************/
718 /* If the previous value was successfully retrieved, restore
719 it before returning control to the non-proxy routines
721 Arguments: fd - File descriptor for input
722 get_ok - Successfully retrieved previous values
723 tvtmp - Time struct with previous values
724 vslen - Length of time struct
728 restore_socket_timeout(int fd, int get_ok, struct timeval tvtmp, socklen_t vslen)
731 setsockopt(fd, SOL_SOCKET, SO_RCVTIMEO, (char *)&tvtmp, vslen);
734 /*************************************************
735 * Check if host is required proxy host *
736 *************************************************/
737 /* The function determines if inbound host will be a regular smtp host
738 or if it is configured that it must use Proxy Protocol.
745 check_proxy_protocol_host()
748 /* Cannot configure local connection as a proxy inbound */
749 if (sender_host_address == NULL) return proxy_session;
751 rc = verify_check_this_host(CUSS &hosts_proxy, NULL, NULL,
752 sender_host_address, NULL);
756 debug_printf("Detected proxy protocol configured host\n");
757 proxy_session = TRUE;
759 return proxy_session;
763 /*************************************************
764 * Setup host for proxy protocol *
765 *************************************************/
766 /* The function configures the connection based on a header from the
767 inbound host to use Proxy Protocol. The specification is very exact
768 so exit with an error if do not find the exact required pieces. This
769 includes an incorrect number of spaces separating args.
776 setup_proxy_protocol_host()
788 struct { /* TCP/UDP over IPv4, len = 12 */
794 struct { /* TCP/UDP over IPv6, len = 36 */
795 uint8_t src_addr[16];
796 uint8_t dst_addr[16];
800 struct { /* AF_UNIX sockets, len = 216 */
801 uschar src_addr[108];
802 uschar dst_addr[108];
808 /* Temp variables used in PPv2 address:port parsing */
810 char tmpip[INET_ADDRSTRLEN];
811 struct sockaddr_in tmpaddr;
812 char tmpip6[INET6_ADDRSTRLEN];
813 struct sockaddr_in6 tmpaddr6;
817 const char v2sig[12] = "\x0D\x0A\x0D\x0A\x00\x0D\x0A\x51\x55\x49\x54\x0A";
818 uschar *iptype; /* To display debug info */
821 struct timeval tvtmp;
823 vslen = sizeof(struct timeval);
825 fd = fileno(smtp_in);
827 /* Save current socket timeout values */
828 get_ok = getsockopt(fd, SOL_SOCKET, SO_RCVTIMEO, (char *)&tvtmp,
831 /* Proxy Protocol host must send header within a short time
832 (default 3 seconds) or it's considered invalid */
833 tv.tv_sec = PROXY_NEGOTIATION_TIMEOUT_SEC;
834 tv.tv_usec = PROXY_NEGOTIATION_TIMEOUT_USEC;
835 setsockopt(fd, SOL_SOCKET, SO_RCVTIMEO, (char *)&tv,
836 sizeof(struct timeval));
840 /* The inbound host was declared to be a Proxy Protocol host, so
841 don't do a PEEK into the data, actually slurp it up. */
842 ret = recv(fd, &hdr, sizeof(hdr), 0);
844 while (ret == -1 && errno == EINTR);
848 restore_socket_timeout(fd, get_ok, tvtmp, vslen);
849 return (errno == EAGAIN) ? 0 : ERRNO_PROXYFAIL;
853 memcmp(&hdr.v2, v2sig, 12) == 0)
857 /* May 2014: haproxy combined the version and command into one byte to
858 allow two full bytes for the length field in order to proxy SSL
859 connections. SSL Proxy is not supported in this version of Exim, but
860 must still seperate values here. */
861 ver = (hdr.v2.ver_cmd & 0xf0) >> 4;
862 cmd = (hdr.v2.ver_cmd & 0x0f);
866 DEBUG(D_receive) debug_printf("Invalid Proxy Protocol version: %d\n", ver);
869 DEBUG(D_receive) debug_printf("Detected PROXYv2 header\n");
870 /* The v2 header will always be 16 bytes per the spec. */
871 size = 16 + hdr.v2.len;
874 DEBUG(D_receive) debug_printf("Truncated or too large PROXYv2 header (%d/%d)\n",
880 case 0x01: /* PROXY command */
883 case 0x11: /* TCPv4 address type */
885 tmpaddr.sin_addr.s_addr = hdr.v2.addr.ip4.src_addr;
886 inet_ntop(AF_INET, &(tmpaddr.sin_addr), (char *)&tmpip, sizeof(tmpip));
887 if (!string_is_ip_address(US tmpip,NULL))
889 DEBUG(D_receive) debug_printf("Invalid %s source IP\n", iptype);
890 return ERRNO_PROXYFAIL;
892 proxy_local_address = sender_host_address;
893 sender_host_address = string_copy(US tmpip);
894 tmpport = ntohs(hdr.v2.addr.ip4.src_port);
895 proxy_local_port = sender_host_port;
896 sender_host_port = tmpport;
897 /* Save dest ip/port */
898 tmpaddr.sin_addr.s_addr = hdr.v2.addr.ip4.dst_addr;
899 inet_ntop(AF_INET, &(tmpaddr.sin_addr), (char *)&tmpip, sizeof(tmpip));
900 if (!string_is_ip_address(US tmpip,NULL))
902 DEBUG(D_receive) debug_printf("Invalid %s dest port\n", iptype);
903 return ERRNO_PROXYFAIL;
905 proxy_external_address = string_copy(US tmpip);
906 tmpport = ntohs(hdr.v2.addr.ip4.dst_port);
907 proxy_external_port = tmpport;
909 case 0x21: /* TCPv6 address type */
911 memmove(tmpaddr6.sin6_addr.s6_addr, hdr.v2.addr.ip6.src_addr, 16);
912 inet_ntop(AF_INET6, &(tmpaddr6.sin6_addr), (char *)&tmpip6, sizeof(tmpip6));
913 if (!string_is_ip_address(US tmpip6,NULL))
915 DEBUG(D_receive) debug_printf("Invalid %s source IP\n", iptype);
916 return ERRNO_PROXYFAIL;
918 proxy_local_address = sender_host_address;
919 sender_host_address = string_copy(US tmpip6);
920 tmpport = ntohs(hdr.v2.addr.ip6.src_port);
921 proxy_local_port = sender_host_port;
922 sender_host_port = tmpport;
923 /* Save dest ip/port */
924 memmove(tmpaddr6.sin6_addr.s6_addr, hdr.v2.addr.ip6.dst_addr, 16);
925 inet_ntop(AF_INET6, &(tmpaddr6.sin6_addr), (char *)&tmpip6, sizeof(tmpip6));
926 if (!string_is_ip_address(US tmpip6,NULL))
928 DEBUG(D_receive) debug_printf("Invalid %s dest port\n", iptype);
929 return ERRNO_PROXYFAIL;
931 proxy_external_address = string_copy(US tmpip6);
932 tmpport = ntohs(hdr.v2.addr.ip6.dst_port);
933 proxy_external_port = tmpport;
937 debug_printf("Unsupported PROXYv2 connection type: 0x%02x\n",
941 /* Unsupported protocol, keep local connection address */
943 case 0x00: /* LOCAL command */
944 /* Keep local connection address for LOCAL */
948 debug_printf("Unsupported PROXYv2 command: 0x%x\n", cmd);
953 memcmp(hdr.v1.line, "PROXY", 5) == 0)
955 uschar *p = string_copy(hdr.v1.line);
956 uschar *end = memchr(p, '\r', ret - 1);
957 uschar *sp; /* Utility variables follow */
961 if (!end || end[1] != '\n')
963 DEBUG(D_receive) debug_printf("Partial or invalid PROXY header\n");
966 *end = '\0'; /* Terminate the string */
967 size = end + 2 - hdr.v1.line; /* Skip header + CRLF */
968 DEBUG(D_receive) debug_printf("Detected PROXYv1 header\n");
969 /* Step through the string looking for the required fields. Ensure
970 strict adherance to required formatting, exit for any error. */
972 if (!isspace(*(p++)))
974 DEBUG(D_receive) debug_printf("Missing space after PROXY command\n");
977 if (!Ustrncmp(p, CCS"TCP4", 4))
979 else if (!Ustrncmp(p,CCS"TCP6", 4))
981 else if (!Ustrncmp(p,CCS"UNKNOWN", 7))
983 iptype = US"Unknown";
988 DEBUG(D_receive) debug_printf("Invalid TCP type\n");
992 p += Ustrlen(iptype);
993 if (!isspace(*(p++)))
995 DEBUG(D_receive) debug_printf("Missing space after TCP4/6 command\n");
998 /* Find the end of the arg */
999 if ((sp = Ustrchr(p, ' ')) == NULL)
1002 debug_printf("Did not find proxied src %s\n", iptype);
1006 if(!string_is_ip_address(p,NULL))
1009 debug_printf("Proxied src arg is not an %s address\n", iptype);
1012 proxy_local_address = sender_host_address;
1013 sender_host_address = p;
1015 if ((sp = Ustrchr(p, ' ')) == NULL)
1018 debug_printf("Did not find proxy dest %s\n", iptype);
1022 if(!string_is_ip_address(p,NULL))
1025 debug_printf("Proxy dest arg is not an %s address\n", iptype);
1028 proxy_external_address = p;
1030 if ((sp = Ustrchr(p, ' ')) == NULL)
1032 DEBUG(D_receive) debug_printf("Did not find proxied src port\n");
1036 tmp_port = strtol(CCS p,&endc,10);
1037 if (*endc || tmp_port == 0)
1040 debug_printf("Proxied src port '%s' not an integer\n", p);
1043 proxy_local_port = sender_host_port;
1044 sender_host_port = tmp_port;
1046 if ((sp = Ustrchr(p, '\0')) == NULL)
1048 DEBUG(D_receive) debug_printf("Did not find proxy dest port\n");
1051 tmp_port = strtol(CCS p,&endc,10);
1052 if (*endc || tmp_port == 0)
1055 debug_printf("Proxy dest port '%s' not an integer\n", p);
1058 proxy_external_port = tmp_port;
1059 /* Already checked for /r /n above. Good V1 header received. */
1064 /* Wrong protocol */
1065 DEBUG(D_receive) debug_printf("Invalid proxy protocol version negotiation\n");
1070 restore_socket_timeout(fd, get_ok, tvtmp, vslen);
1071 /* Don't flush any potential buffer contents. Any input should cause a
1072 synchronization failure */
1076 restore_socket_timeout(fd, get_ok, tvtmp, vslen);
1078 debug_printf("Valid %s sender from Proxy Protocol header\n", iptype);
1079 return proxy_session;
1083 /*************************************************
1084 * Read one command line *
1085 *************************************************/
1087 /* Strictly, SMTP commands coming over the net are supposed to end with CRLF.
1088 There are sites that don't do this, and in any case internal SMTP probably
1089 should check only for LF. Consequently, we check here for LF only. The line
1090 ends up with [CR]LF removed from its end. If we get an overlong line, treat as
1091 an unknown command. The command is read into the global smtp_cmd_buffer so that
1092 it is available via $smtp_command.
1094 The character reading routine sets up a timeout for each block actually read
1095 from the input (which may contain more than one command). We set up a special
1096 signal handler that closes down the session on a timeout. Control does not
1097 return when it runs.
1100 check_sync if TRUE, check synchronization rules if global option is TRUE
1102 Returns: a code identifying the command (enumerated above)
1106 smtp_read_command(BOOL check_sync)
1111 BOOL hadnull = FALSE;
1113 os_non_restarting_signal(SIGALRM, command_timeout_handler);
1115 while ((c = (receive_getc)()) != '\n' && c != EOF)
1117 if (ptr >= smtp_cmd_buffer_size)
1119 os_non_restarting_signal(SIGALRM, sigalrm_handler);
1127 smtp_cmd_buffer[ptr++] = c;
1130 receive_linecount++; /* For BSMTP errors */
1131 os_non_restarting_signal(SIGALRM, sigalrm_handler);
1133 /* If hit end of file, return pseudo EOF command. Whether we have a
1134 part-line already read doesn't matter, since this is an error state. */
1136 if (c == EOF) return EOF_CMD;
1138 /* Remove any CR and white space at the end of the line, and terminate the
1141 while (ptr > 0 && isspace(smtp_cmd_buffer[ptr-1])) ptr--;
1142 smtp_cmd_buffer[ptr] = 0;
1144 DEBUG(D_receive) debug_printf("SMTP<< %s\n", smtp_cmd_buffer);
1146 /* NULLs are not allowed in SMTP commands */
1148 if (hadnull) return BADCHAR_CMD;
1150 /* Scan command list and return identity, having set the data pointer
1151 to the start of the actual data characters. Check for SMTP synchronization
1154 for (p = cmd_list; p < cmd_list_end; p++)
1156 #ifdef SUPPORT_PROXY
1157 /* Only allow QUIT command if Proxy Protocol parsing failed */
1158 if (proxy_session && proxy_session_failed)
1160 if (p->cmd != QUIT_CMD)
1165 && strncmpic(smtp_cmd_buffer, US p->name, p->len) == 0
1166 && ( smtp_cmd_buffer[p->len-1] == ':' /* "mail from:" or "rcpt to:" */
1167 || smtp_cmd_buffer[p->len] == 0
1168 || smtp_cmd_buffer[p->len] == ' '
1171 if (smtp_inptr < smtp_inend && /* Outstanding input */
1172 p->cmd < sync_cmd_limit && /* Command should sync */
1173 check_sync && /* Local flag set */
1174 smtp_enforce_sync && /* Global flag set */
1175 sender_host_address != NULL && /* Not local input */
1176 !sender_host_notsocket) /* Really is a socket */
1179 /* The variables $smtp_command and $smtp_command_argument point into the
1180 unmodified input buffer. A copy of the latter is taken for actual
1181 processing, so that it can be chopped up into separate parts if necessary,
1182 for example, when processing a MAIL command options such as SIZE that can
1183 follow the sender address. */
1185 smtp_cmd_argument = smtp_cmd_buffer + p->len;
1186 while (isspace(*smtp_cmd_argument)) smtp_cmd_argument++;
1187 Ustrcpy(smtp_data_buffer, smtp_cmd_argument);
1188 smtp_cmd_data = smtp_data_buffer;
1190 /* Count non-mail commands from those hosts that are controlled in this
1191 way. The default is all hosts. We don't waste effort checking the list
1192 until we get a non-mail command, but then cache the result to save checking
1193 again. If there's a DEFER while checking the host, assume it's in the list.
1195 Note that one instance of RSET, EHLO/HELO, and STARTTLS is allowed at the
1196 start of each incoming message by fiddling with the value in the table. */
1198 if (!p->is_mail_cmd)
1200 if (count_nonmail == TRUE_UNSET) count_nonmail =
1201 verify_check_host(&smtp_accept_max_nonmail_hosts) != FAIL;
1202 if (count_nonmail && ++nonmail_command_count > smtp_accept_max_nonmail)
1203 return TOO_MANY_NONMAIL_CMD;
1206 /* If there is data for a command that does not expect it, generate the
1209 return (p->has_arg || *smtp_cmd_data == 0)? p->cmd : BADARG_CMD;
1213 #ifdef SUPPORT_PROXY
1214 /* Only allow QUIT command if Proxy Protocol parsing failed */
1215 if (proxy_session && proxy_session_failed)
1216 return PROXY_FAIL_IGNORE_CMD;
1219 /* Enforce synchronization for unknown commands */
1221 if (smtp_inptr < smtp_inend && /* Outstanding input */
1222 check_sync && /* Local flag set */
1223 smtp_enforce_sync && /* Global flag set */
1224 sender_host_address != NULL && /* Not local input */
1225 !sender_host_notsocket) /* Really is a socket */
1233 /*************************************************
1234 * Recheck synchronization *
1235 *************************************************/
1237 /* Synchronization checks can never be perfect because a packet may be on its
1238 way but not arrived when the check is done. Such checks can in any case only be
1239 done when TLS is not in use. Normally, the checks happen when commands are
1240 read: Exim ensures that there is no more input in the input buffer. In normal
1241 cases, the response to the command will be fast, and there is no further check.
1243 However, for some commands an ACL is run, and that can include delays. In those
1244 cases, it is useful to do another check on the input just before sending the
1245 response. This also applies at the start of a connection. This function does
1246 that check by means of the select() function, as long as the facility is not
1247 disabled or inappropriate. A failure of select() is ignored.
1249 When there is unwanted input, we read it so that it appears in the log of the
1253 Returns: TRUE if all is well; FALSE if there is input pending
1261 struct timeval tzero;
1263 if (!smtp_enforce_sync || sender_host_address == NULL ||
1264 sender_host_notsocket || tls_in.active >= 0)
1267 fd = fileno(smtp_in);
1272 rc = select(fd + 1, (SELECT_ARG2_TYPE *)&fds, NULL, NULL, &tzero);
1274 if (rc <= 0) return TRUE; /* Not ready to read */
1276 if (rc < 0) return TRUE; /* End of file or error */
1279 rc = smtp_inend - smtp_inptr;
1280 if (rc > 150) rc = 150;
1287 /*************************************************
1288 * Forced closedown of call *
1289 *************************************************/
1291 /* This function is called from log.c when Exim is dying because of a serious
1292 disaster, and also from some other places. If an incoming non-batched SMTP
1293 channel is open, it swallows the rest of the incoming message if in the DATA
1294 phase, sends the reply string, and gives an error to all subsequent commands
1295 except QUIT. The existence of an SMTP call is detected by the non-NULLness of
1299 message SMTP reply string to send, excluding the code
1305 smtp_closedown(uschar *message)
1307 if (smtp_in == NULL || smtp_batched_input) return;
1308 receive_swallow_smtp();
1309 smtp_printf("421 %s\r\n", message);
1313 switch(smtp_read_command(FALSE))
1319 smtp_printf("221 %s closing connection\r\n", smtp_active_hostname);
1324 smtp_printf("250 Reset OK\r\n");
1328 smtp_printf("421 %s\r\n", message);
1337 /*************************************************
1338 * Set up connection info for logging *
1339 *************************************************/
1341 /* This function is called when logging information about an SMTP connection.
1342 It sets up appropriate source information, depending on the type of connection.
1343 If sender_fullhost is NULL, we are at a very early stage of the connection;
1344 just use the IP address.
1347 Returns: a string describing the connection
1351 smtp_get_connection_info(void)
1353 uschar *hostname = (sender_fullhost == NULL)?
1354 sender_host_address : sender_fullhost;
1357 return string_sprintf("SMTP connection from %s", hostname);
1359 if (sender_host_unknown || sender_host_notsocket)
1360 return string_sprintf("SMTP connection from %s", sender_ident);
1363 return string_sprintf("SMTP connection from %s (via inetd)", hostname);
1365 if (LOGGING(incoming_interface) && interface_address != NULL)
1366 return string_sprintf("SMTP connection from %s I=[%s]:%d", hostname,
1367 interface_address, interface_port);
1369 return string_sprintf("SMTP connection from %s", hostname);
1375 /* Append TLS-related information to a log line
1378 s String under construction: allocated string to extend, or NULL
1379 sizep Pointer to current allocation size (update on return), or NULL
1380 ptrp Pointer to index for new entries in string (update on return), or NULL
1382 Returns: Allocated string or NULL
1385 s_tlslog(uschar * s, int * sizep, int * ptrp)
1387 int size = sizep ? *sizep : 0;
1388 int ptr = ptrp ? *ptrp : 0;
1390 if (LOGGING(tls_cipher) && tls_in.cipher != NULL)
1391 s = string_append(s, &size, &ptr, 2, US" X=", tls_in.cipher);
1392 if (LOGGING(tls_certificate_verified) && tls_in.cipher != NULL)
1393 s = string_append(s, &size, &ptr, 2, US" CV=",
1394 tls_in.certificate_verified? "yes":"no");
1395 if (LOGGING(tls_peerdn) && tls_in.peerdn != NULL)
1396 s = string_append(s, &size, &ptr, 3, US" DN=\"",
1397 string_printing(tls_in.peerdn), US"\"");
1398 if (LOGGING(tls_sni) && tls_in.sni != NULL)
1399 s = string_append(s, &size, &ptr, 3, US" SNI=\"",
1400 string_printing(tls_in.sni), US"\"");
1405 if (sizep) *sizep = size;
1406 if (ptrp) *ptrp = ptr;
1412 /*************************************************
1413 * Log lack of MAIL if so configured *
1414 *************************************************/
1416 /* This function is called when an SMTP session ends. If the log selector
1417 smtp_no_mail is set, write a log line giving some details of what has happened
1418 in the SMTP session.
1425 smtp_log_no_mail(void)
1430 if (smtp_mailcmd_count > 0 || !LOGGING(smtp_no_mail))
1436 if (sender_host_authenticated != NULL)
1438 s = string_append(s, &size, &ptr, 2, US" A=", sender_host_authenticated);
1439 if (authenticated_id != NULL)
1440 s = string_append(s, &size, &ptr, 2, US":", authenticated_id);
1444 s = s_tlslog(s, &size, &ptr);
1447 sep = (smtp_connection_had[SMTP_HBUFF_SIZE-1] != SCH_NONE)?
1448 US" C=..." : US" C=";
1449 for (i = smtp_ch_index; i < SMTP_HBUFF_SIZE; i++)
1451 if (smtp_connection_had[i] != SCH_NONE)
1453 s = string_append(s, &size, &ptr, 2, sep,
1454 smtp_names[smtp_connection_had[i]]);
1459 for (i = 0; i < smtp_ch_index; i++)
1461 s = string_append(s, &size, &ptr, 2, sep, smtp_names[smtp_connection_had[i]]);
1465 if (s != NULL) s[ptr] = 0; else s = US"";
1466 log_write(0, LOG_MAIN, "no MAIL in SMTP connection from %s D=%s%s",
1467 host_and_ident(FALSE),
1468 readconf_printtime( (int) ((long)time(NULL) - (long)smtp_connection_start)),
1474 /*************************************************
1475 * Check HELO line and set sender_helo_name *
1476 *************************************************/
1478 /* Check the format of a HELO line. The data for HELO/EHLO is supposed to be
1479 the domain name of the sending host, or an ip literal in square brackets. The
1480 arrgument is placed in sender_helo_name, which is in malloc store, because it
1481 must persist over multiple incoming messages. If helo_accept_junk is set, this
1482 host is permitted to send any old junk (needed for some broken hosts).
1483 Otherwise, helo_allow_chars can be used for rogue characters in general
1484 (typically people want to let in underscores).
1487 s the data portion of the line (already past any white space)
1489 Returns: TRUE or FALSE
1493 check_helo(uschar *s)
1496 uschar *end = s + Ustrlen(s);
1497 BOOL yield = helo_accept_junk;
1499 /* Discard any previous helo name */
1501 if (sender_helo_name != NULL)
1503 store_free(sender_helo_name);
1504 sender_helo_name = NULL;
1507 /* Skip tests if junk is permitted. */
1511 /* Allow the new standard form for IPv6 address literals, namely,
1512 [IPv6:....], and because someone is bound to use it, allow an equivalent
1513 IPv4 form. Allow plain addresses as well. */
1520 if (strncmpic(s, US"[IPv6:", 6) == 0)
1521 yield = (string_is_ip_address(s+6, NULL) == 6);
1522 else if (strncmpic(s, US"[IPv4:", 6) == 0)
1523 yield = (string_is_ip_address(s+6, NULL) == 4);
1525 yield = (string_is_ip_address(s+1, NULL) != 0);
1530 /* Non-literals must be alpha, dot, hyphen, plus any non-valid chars
1531 that have been configured (usually underscore - sigh). */
1538 if (!isalnum(*s) && *s != '.' && *s != '-' &&
1539 Ustrchr(helo_allow_chars, *s) == NULL)
1549 /* Save argument if OK */
1551 if (yield) sender_helo_name = string_copy_malloc(start);
1559 /*************************************************
1560 * Extract SMTP command option *
1561 *************************************************/
1563 /* This function picks the next option setting off the end of smtp_cmd_data. It
1564 is called for MAIL FROM and RCPT TO commands, to pick off the optional ESMTP
1565 things that can appear there.
1568 name point this at the name
1569 value point this at the data string
1571 Returns: TRUE if found an option
1575 extract_option(uschar **name, uschar **value)
1578 uschar *v = smtp_cmd_data + Ustrlen(smtp_cmd_data) - 1;
1579 while (isspace(*v)) v--;
1581 while (v > smtp_cmd_data && *v != '=' && !isspace(*v)) v--;
1586 while(isalpha(n[-1])) n--;
1587 /* RFC says SP, but TAB seen in wild and other major MTAs accept it */
1588 if (!isspace(n[-1])) return FALSE;
1594 if (v == smtp_cmd_data) return FALSE;
1606 /*************************************************
1607 * Reset for new message *
1608 *************************************************/
1610 /* This function is called whenever the SMTP session is reset from
1611 within either of the setup functions.
1613 Argument: the stacking pool storage reset point
1618 smtp_reset(void *reset_point)
1620 store_reset(reset_point);
1621 recipients_list = NULL;
1622 rcpt_count = rcpt_defer_count = rcpt_fail_count =
1623 raw_recipients_count = recipients_count = recipients_list_max = 0;
1624 cancel_cutthrough_connection("smtp reset");
1625 message_linecount = 0;
1627 acl_added_headers = NULL;
1628 acl_removed_headers = NULL;
1629 queue_only_policy = FALSE;
1630 rcpt_smtp_response = NULL;
1631 rcpt_smtp_response_same = TRUE;
1632 rcpt_in_progress = FALSE;
1633 deliver_freeze = FALSE; /* Can be set by ACL */
1634 freeze_tell = freeze_tell_config; /* Can be set by ACL */
1635 fake_response = OK; /* Can be set by ACL */
1636 #ifdef WITH_CONTENT_SCAN
1637 no_mbox_unspool = FALSE; /* Can be set by ACL */
1639 submission_mode = FALSE; /* Can be set by ACL */
1640 suppress_local_fixups = suppress_local_fixups_default; /* Can be set by ACL */
1641 active_local_from_check = local_from_check; /* Can be set by ACL */
1642 active_local_sender_retain = local_sender_retain; /* Can be set by ACL */
1643 sender_address = NULL;
1644 submission_name = NULL; /* Can be set by ACL */
1645 raw_sender = NULL; /* After SMTP rewrite, before qualifying */
1646 sender_address_unrewritten = NULL; /* Set only after verify rewrite */
1647 sender_verified_list = NULL; /* No senders verified */
1648 memset(sender_address_cache, 0, sizeof(sender_address_cache));
1649 memset(sender_domain_cache, 0, sizeof(sender_domain_cache));
1651 authenticated_sender = NULL;
1652 #ifdef EXPERIMENTAL_BRIGHTMAIL
1654 bmi_verdicts = NULL;
1656 #ifndef DISABLE_DKIM
1657 dkim_signers = NULL;
1658 dkim_disable_verify = FALSE;
1659 dkim_collect_input = FALSE;
1663 #ifndef DISABLE_PRDR
1664 prdr_requested = FALSE;
1666 #ifdef EXPERIMENTAL_SPF
1667 spf_header_comment = NULL;
1668 spf_received = NULL;
1670 spf_smtp_comment = NULL;
1673 message_smtputf8 = FALSE;
1675 body_linecount = body_zerocount = 0;
1677 sender_rate = sender_rate_limit = sender_rate_period = NULL;
1678 ratelimiters_mail = NULL; /* Updated by ratelimit ACL condition */
1679 /* Note that ratelimiters_conn persists across resets. */
1681 /* Reset message ACL variables */
1685 /* The message body variables use malloc store. They may be set if this is
1686 not the first message in an SMTP session and the previous message caused them
1687 to be referenced in an ACL. */
1689 if (message_body != NULL)
1691 store_free(message_body);
1692 message_body = NULL;
1695 if (message_body_end != NULL)
1697 store_free(message_body_end);
1698 message_body_end = NULL;
1701 /* Warning log messages are also saved in malloc store. They are saved to avoid
1702 repetition in the same message, but it seems right to repeat them for different
1705 while (acl_warn_logged != NULL)
1707 string_item *this = acl_warn_logged;
1708 acl_warn_logged = acl_warn_logged->next;
1717 /*************************************************
1718 * Initialize for incoming batched SMTP message *
1719 *************************************************/
1721 /* This function is called from smtp_setup_msg() in the case when
1722 smtp_batched_input is true. This happens when -bS is used to pass a whole batch
1723 of messages in one file with SMTP commands between them. All errors must be
1724 reported by sending a message, and only MAIL FROM, RCPT TO, and DATA are
1725 relevant. After an error on a sender, or an invalid recipient, the remainder
1726 of the message is skipped. The value of received_protocol is already set.
1729 Returns: > 0 message successfully started (reached DATA)
1730 = 0 QUIT read or end of file reached
1731 < 0 should not occur
1735 smtp_setup_batch_msg(void)
1738 void *reset_point = store_get(0);
1740 /* Save the line count at the start of each transaction - single commands
1741 like HELO and RSET count as whole transactions. */
1743 bsmtp_transaction_linecount = receive_linecount;
1745 if ((receive_feof)()) return 0; /* Treat EOF as QUIT */
1747 smtp_reset(reset_point); /* Reset for start of message */
1749 /* Deal with SMTP commands. This loop is exited by setting done to a POSITIVE
1750 value. The values are 2 larger than the required yield of the function. */
1755 uschar *recipient = NULL;
1756 int start, end, sender_domain, recipient_domain;
1758 switch(smtp_read_command(FALSE))
1760 /* The HELO/EHLO commands set sender_address_helo if they have
1761 valid data; otherwise they are ignored, except that they do
1762 a reset of the state. */
1767 check_helo(smtp_cmd_data);
1771 smtp_reset(reset_point);
1772 bsmtp_transaction_linecount = receive_linecount;
1776 /* The MAIL FROM command requires an address as an operand. All we
1777 do here is to parse it for syntactic correctness. The form "<>" is
1778 a special case which converts into an empty string. The start/end
1779 pointers in the original are not used further for this address, as
1780 it is the canonical extracted address which is all that is kept. */
1783 smtp_mailcmd_count++; /* Count for no-mail log */
1784 if (sender_address != NULL)
1785 /* The function moan_smtp_batch() does not return. */
1786 moan_smtp_batch(smtp_cmd_buffer, "503 Sender already given");
1788 if (smtp_cmd_data[0] == 0)
1789 /* The function moan_smtp_batch() does not return. */
1790 moan_smtp_batch(smtp_cmd_buffer, "501 MAIL FROM must have an address operand");
1792 /* Reset to start of message */
1794 smtp_reset(reset_point);
1796 /* Apply SMTP rewrite */
1798 raw_sender = ((rewrite_existflags & rewrite_smtp) != 0)?
1799 rewrite_one(smtp_cmd_data, rewrite_smtp|rewrite_smtp_sender, NULL, FALSE,
1800 US"", global_rewrite_rules) : smtp_cmd_data;
1802 /* Extract the address; the TRUE flag allows <> as valid */
1805 parse_extract_address(raw_sender, &errmess, &start, &end, &sender_domain,
1808 if (raw_sender == NULL)
1809 /* The function moan_smtp_batch() does not return. */
1810 moan_smtp_batch(smtp_cmd_buffer, "501 %s", errmess);
1812 sender_address = string_copy(raw_sender);
1814 /* Qualify unqualified sender addresses if permitted to do so. */
1816 if (sender_domain == 0 && sender_address[0] != 0 && sender_address[0] != '@')
1818 if (allow_unqualified_sender)
1820 sender_address = rewrite_address_qualify(sender_address, FALSE);
1821 DEBUG(D_receive) debug_printf("unqualified address %s accepted "
1822 "and rewritten\n", raw_sender);
1824 /* The function moan_smtp_batch() does not return. */
1825 else moan_smtp_batch(smtp_cmd_buffer, "501 sender address must contain "
1831 /* The RCPT TO command requires an address as an operand. All we do
1832 here is to parse it for syntactic correctness. There may be any number
1833 of RCPT TO commands, specifying multiple senders. We build them all into
1834 a data structure that is in argc/argv format. The start/end values
1835 given by parse_extract_address are not used, as we keep only the
1836 extracted address. */
1839 if (sender_address == NULL)
1840 /* The function moan_smtp_batch() does not return. */
1841 moan_smtp_batch(smtp_cmd_buffer, "503 No sender yet given");
1843 if (smtp_cmd_data[0] == 0)
1844 /* The function moan_smtp_batch() does not return. */
1845 moan_smtp_batch(smtp_cmd_buffer, "501 RCPT TO must have an address operand");
1847 /* Check maximum number allowed */
1849 if (recipients_max > 0 && recipients_count + 1 > recipients_max)
1850 /* The function moan_smtp_batch() does not return. */
1851 moan_smtp_batch(smtp_cmd_buffer, "%s too many recipients",
1852 recipients_max_reject? "552": "452");
1854 /* Apply SMTP rewrite, then extract address. Don't allow "<>" as a
1855 recipient address */
1857 recipient = rewrite_existflags & rewrite_smtp
1858 ? rewrite_one(smtp_cmd_data, rewrite_smtp, NULL, FALSE, US"",
1859 global_rewrite_rules)
1862 recipient = parse_extract_address(recipient, &errmess, &start, &end,
1863 &recipient_domain, FALSE);
1866 /* The function moan_smtp_batch() does not return. */
1867 moan_smtp_batch(smtp_cmd_buffer, "501 %s", errmess);
1869 /* If the recipient address is unqualified, qualify it if permitted. Then
1870 add it to the list of recipients. */
1872 if (recipient_domain == 0)
1874 if (allow_unqualified_recipient)
1876 DEBUG(D_receive) debug_printf("unqualified address %s accepted\n",
1878 recipient = rewrite_address_qualify(recipient, TRUE);
1880 /* The function moan_smtp_batch() does not return. */
1881 else moan_smtp_batch(smtp_cmd_buffer, "501 recipient address must contain "
1884 receive_add_recipient(recipient, -1);
1888 /* The DATA command is legal only if it follows successful MAIL FROM
1889 and RCPT TO commands. This function is complete when a valid DATA
1890 command is encountered. */
1893 if (sender_address == NULL || recipients_count <= 0)
1895 /* The function moan_smtp_batch() does not return. */
1896 if (sender_address == NULL)
1897 moan_smtp_batch(smtp_cmd_buffer,
1898 "503 MAIL FROM:<sender> command must precede DATA");
1900 moan_smtp_batch(smtp_cmd_buffer,
1901 "503 RCPT TO:<recipient> must precede DATA");
1905 done = 3; /* DATA successfully achieved */
1906 message_ended = END_NOTENDED; /* Indicate in middle of message */
1911 /* The VRFY, EXPN, HELP, ETRN, and NOOP commands are ignored. */
1918 bsmtp_transaction_linecount = receive_linecount;
1929 /* The function moan_smtp_batch() does not return. */
1930 moan_smtp_batch(smtp_cmd_buffer, "501 Unexpected argument data");
1935 /* The function moan_smtp_batch() does not return. */
1936 moan_smtp_batch(smtp_cmd_buffer, "501 Unexpected NULL in SMTP command");
1941 /* The function moan_smtp_batch() does not return. */
1942 moan_smtp_batch(smtp_cmd_buffer, "500 Command unrecognized");
1947 return done - 2; /* Convert yield values */
1953 /*************************************************
1954 * Start an SMTP session *
1955 *************************************************/
1957 /* This function is called at the start of an SMTP session. Thereafter,
1958 smtp_setup_msg() is called to initiate each separate message. This
1959 function does host-specific testing, and outputs the banner line.
1962 Returns: FALSE if the session can not continue; something has
1963 gone wrong, or the connection to the host is blocked
1967 smtp_start_session(void)
1971 uschar *user_msg, *log_msg;
1975 smtp_connection_start = time(NULL);
1976 for (smtp_ch_index = 0; smtp_ch_index < SMTP_HBUFF_SIZE; smtp_ch_index++)
1977 smtp_connection_had[smtp_ch_index] = SCH_NONE;
1980 /* Default values for certain variables */
1982 helo_seen = esmtp = helo_accept_junk = FALSE;
1983 smtp_mailcmd_count = 0;
1984 count_nonmail = TRUE_UNSET;
1985 synprot_error_count = unknown_command_count = nonmail_command_count = 0;
1986 smtp_delay_mail = smtp_rlm_base;
1987 auth_advertised = FALSE;
1988 pipelining_advertised = FALSE;
1989 pipelining_enable = TRUE;
1990 sync_cmd_limit = NON_SYNC_CMD_NON_PIPELINING;
1991 smtp_exit_function_called = FALSE; /* For avoiding loop in not-quit exit */
1993 /* If receiving by -bs from a trusted user, or testing with -bh, we allow
1994 authentication settings from -oMaa to remain in force. */
1996 if (!host_checking && !sender_host_notsocket) sender_host_authenticated = NULL;
1997 authenticated_by = NULL;
2000 tls_in.cipher = tls_in.peerdn = NULL;
2001 tls_in.ourcert = tls_in.peercert = NULL;
2003 tls_in.ocsp = OCSP_NOT_REQ;
2004 tls_advertised = FALSE;
2006 dsn_advertised = FALSE;
2008 smtputf8_advertised = FALSE;
2011 /* Reset ACL connection variables */
2015 /* Allow for trailing 0 in the command and data buffers. */
2017 smtp_cmd_buffer = (uschar *)malloc(2*smtp_cmd_buffer_size + 2);
2018 if (smtp_cmd_buffer == NULL)
2019 log_write(0, LOG_MAIN|LOG_PANIC_DIE,
2020 "malloc() failed for SMTP command buffer");
2021 smtp_cmd_buffer[0] = 0;
2022 smtp_data_buffer = smtp_cmd_buffer + smtp_cmd_buffer_size + 1;
2024 /* For batched input, the protocol setting can be overridden from the
2025 command line by a trusted caller. */
2027 if (smtp_batched_input)
2029 if (received_protocol == NULL) received_protocol = US"local-bsmtp";
2032 /* For non-batched SMTP input, the protocol setting is forced here. It will be
2033 reset later if any of EHLO/AUTH/STARTTLS are received. */
2037 (sender_host_address ? protocols : protocols_local) [pnormal];
2039 /* Set up the buffer for inputting using direct read() calls, and arrange to
2040 call the local functions instead of the standard C ones. */
2042 smtp_inbuffer = (uschar *)malloc(in_buffer_size);
2043 if (smtp_inbuffer == NULL)
2044 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "malloc() failed for SMTP input buffer");
2045 receive_getc = smtp_getc;
2046 receive_ungetc = smtp_ungetc;
2047 receive_feof = smtp_feof;
2048 receive_ferror = smtp_ferror;
2049 receive_smtp_buffered = smtp_buffered;
2050 smtp_inptr = smtp_inend = smtp_inbuffer;
2051 smtp_had_eof = smtp_had_error = 0;
2053 /* Set up the message size limit; this may be host-specific */
2055 thismessage_size_limit = expand_string_integer(message_size_limit, TRUE);
2056 if (expand_string_message != NULL)
2058 if (thismessage_size_limit == -1)
2059 log_write(0, LOG_MAIN|LOG_PANIC, "unable to expand message_size_limit: "
2060 "%s", expand_string_message);
2062 log_write(0, LOG_MAIN|LOG_PANIC, "invalid message_size_limit: "
2063 "%s", expand_string_message);
2064 smtp_closedown(US"Temporary local problem - please try later");
2068 /* When a message is input locally via the -bs or -bS options, sender_host_
2069 unknown is set unless -oMa was used to force an IP address, in which case it
2070 is checked like a real remote connection. When -bs is used from inetd, this
2071 flag is not set, causing the sending host to be checked. The code that deals
2072 with IP source routing (if configured) is never required for -bs or -bS and
2073 the flag sender_host_notsocket is used to suppress it.
2075 If smtp_accept_max and smtp_accept_reserve are set, keep some connections in
2076 reserve for certain hosts and/or networks. */
2078 if (!sender_host_unknown)
2081 BOOL reserved_host = FALSE;
2083 /* Look up IP options (source routing info) on the socket if this is not an
2084 -oMa "host", and if any are found, log them and drop the connection.
2086 Linux (and others now, see below) is different to everyone else, so there
2087 has to be some conditional compilation here. Versions of Linux before 2.1.15
2088 used a structure whose name was "options". Somebody finally realized that
2089 this name was silly, and it got changed to "ip_options". I use the
2090 newer name here, but there is a fudge in the script that sets up os.h
2091 to define a macro in older Linux systems.
2093 Sigh. Linux is a fast-moving target. Another generation of Linux uses
2094 glibc 2, which has chosen ip_opts for the structure name. This is now
2095 really a glibc thing rather than a Linux thing, so the condition name
2096 has been changed to reflect this. It is relevant also to GNU/Hurd.
2098 Mac OS 10.x (Darwin) is like the later glibc versions, but without the
2099 setting of the __GLIBC__ macro, so we can't detect it automatically. There's
2100 a special macro defined in the os.h file.
2102 Some DGUX versions on older hardware appear not to support IP options at
2103 all, so there is now a general macro which can be set to cut out this
2106 How to do this properly in IPv6 is not yet known. */
2108 #if !HAVE_IPV6 && !defined(NO_IP_OPTIONS)
2110 #ifdef GLIBC_IP_OPTIONS
2111 #if (!defined __GLIBC__) || (__GLIBC__ < 2)
2116 #elif defined DARWIN_IP_OPTIONS
2122 if (!host_checking && !sender_host_notsocket)
2125 EXIM_SOCKLEN_T optlen = sizeof(struct ip_options) + MAX_IPOPTLEN;
2126 struct ip_options *ipopt = store_get(optlen);
2128 struct ip_opts ipoptblock;
2129 struct ip_opts *ipopt = &ipoptblock;
2130 EXIM_SOCKLEN_T optlen = sizeof(ipoptblock);
2132 struct ipoption ipoptblock;
2133 struct ipoption *ipopt = &ipoptblock;
2134 EXIM_SOCKLEN_T optlen = sizeof(ipoptblock);
2137 /* Occasional genuine failures of getsockopt() have been seen - for
2138 example, "reset by peer". Therefore, just log and give up on this
2139 call, unless the error is ENOPROTOOPT. This error is given by systems
2140 that have the interfaces but not the mechanism - e.g. GNU/Hurd at the time
2141 of writing. So for that error, carry on - we just can't do an IP options
2144 DEBUG(D_receive) debug_printf("checking for IP options\n");
2146 if (getsockopt(fileno(smtp_out), IPPROTO_IP, IP_OPTIONS, (uschar *)(ipopt),
2149 if (errno != ENOPROTOOPT)
2151 log_write(0, LOG_MAIN, "getsockopt() failed from %s: %s",
2152 host_and_ident(FALSE), strerror(errno));
2153 smtp_printf("451 SMTP service not available\r\n");
2158 /* Deal with any IP options that are set. On the systems I have looked at,
2159 the value of MAX_IPOPTLEN has been 40, meaning that there should never be
2160 more logging data than will fit in big_buffer. Nevertheless, after somebody
2161 questioned this code, I've added in some paranoid checking. */
2163 else if (optlen > 0)
2165 uschar *p = big_buffer;
2166 uschar *pend = big_buffer + big_buffer_size;
2167 uschar *opt, *adptr;
2169 struct in_addr addr;
2172 uschar *optstart = (uschar *)(ipopt->__data);
2174 uschar *optstart = (uschar *)(ipopt->ip_opts);
2176 uschar *optstart = (uschar *)(ipopt->ipopt_list);
2179 DEBUG(D_receive) debug_printf("IP options exist\n");
2181 Ustrcpy(p, "IP options on incoming call:");
2184 for (opt = optstart; opt != NULL &&
2185 opt < (uschar *)(ipopt) + optlen;)
2199 if (!string_format(p, pend-p, " %s [@%s",
2200 (*opt == IPOPT_SSRR)? "SSRR" : "LSRR",
2202 inet_ntoa(*((struct in_addr *)(&(ipopt->faddr))))))
2204 inet_ntoa(ipopt->ip_dst)))
2206 inet_ntoa(ipopt->ipopt_dst)))
2214 optcount = (opt[1] - 3) / sizeof(struct in_addr);
2216 while (optcount-- > 0)
2218 memcpy(&addr, adptr, sizeof(addr));
2219 if (!string_format(p, pend - p - 1, "%s%s",
2220 (optcount == 0)? ":" : "@", inet_ntoa(addr)))
2226 adptr += sizeof(struct in_addr);
2235 if (pend - p < 4 + 3*opt[1]) { opt = NULL; break; }
2238 for (i = 0; i < opt[1]; i++)
2240 sprintf(CS p, "%2.2x ", opt[i]);
2251 log_write(0, LOG_MAIN, "%s", big_buffer);
2253 /* Refuse any call with IP options. This is what tcpwrappers 7.5 does. */
2255 log_write(0, LOG_MAIN|LOG_REJECT,
2256 "connection from %s refused (IP options)", host_and_ident(FALSE));
2258 smtp_printf("554 SMTP service not available\r\n");
2262 /* Length of options = 0 => there are no options */
2264 else DEBUG(D_receive) debug_printf("no IP options found\n");
2266 #endif /* HAVE_IPV6 && !defined(NO_IP_OPTIONS) */
2268 /* Set keep-alive in socket options. The option is on by default. This
2269 setting is an attempt to get rid of some hanging connections that stick in
2270 read() when the remote end (usually a dialup) goes away. */
2272 if (smtp_accept_keepalive && !sender_host_notsocket)
2273 ip_keepalive(fileno(smtp_out), sender_host_address, FALSE);
2275 /* If the current host matches host_lookup, set the name by doing a
2276 reverse lookup. On failure, sender_host_name will be NULL and
2277 host_lookup_failed will be TRUE. This may or may not be serious - optional
2280 if (verify_check_host(&host_lookup) == OK)
2282 (void)host_name_lookup();
2283 host_build_sender_fullhost();
2286 /* Delay this until we have the full name, if it is looked up. */
2288 set_process_info("handling incoming connection from %s",
2289 host_and_ident(FALSE));
2291 /* Expand smtp_receive_timeout, if needed */
2293 if (smtp_receive_timeout_s)
2296 if ( !(exp = expand_string(smtp_receive_timeout_s))
2298 || (smtp_receive_timeout = readconf_readtime(exp, 0, FALSE)) < 0
2300 log_write(0, LOG_MAIN|LOG_PANIC,
2301 "bad value for smtp_receive_timeout: '%s'", exp ? exp : US"");
2304 /* Start up TLS if tls_on_connect is set. This is for supporting the legacy
2305 smtps port for use with older style SSL MTAs. */
2308 if (tls_in.on_connect && tls_server_start(tls_require_ciphers) != OK)
2312 /* Test for explicit connection rejection */
2314 if (verify_check_host(&host_reject_connection) == OK)
2316 log_write(L_connection_reject, LOG_MAIN|LOG_REJECT, "refused connection "
2317 "from %s (host_reject_connection)", host_and_ident(FALSE));
2318 smtp_printf("554 SMTP service not available\r\n");
2322 /* Test with TCP Wrappers if so configured. There is a problem in that
2323 hosts_ctl() returns 0 (deny) under a number of system failure circumstances,
2324 such as disks dying. In these cases, it is desirable to reject with a 4xx
2325 error instead of a 5xx error. There isn't a "right" way to detect such
2326 problems. The following kludge is used: errno is zeroed before calling
2327 hosts_ctl(). If the result is "reject", a 5xx error is given only if the
2328 value of errno is 0 or ENOENT (which happens if /etc/hosts.{allow,deny} does
2331 #ifdef USE_TCP_WRAPPERS
2333 tcp_wrappers_name = expand_string(tcp_wrappers_daemon_name);
2334 if (tcp_wrappers_name == NULL)
2336 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "Expansion of \"%s\" "
2337 "(tcp_wrappers_name) failed: %s", string_printing(tcp_wrappers_name),
2338 expand_string_message);
2340 if (!hosts_ctl(tcp_wrappers_name,
2341 (sender_host_name == NULL)? STRING_UNKNOWN : CS sender_host_name,
2342 (sender_host_address == NULL)? STRING_UNKNOWN : CS sender_host_address,
2343 (sender_ident == NULL)? STRING_UNKNOWN : CS sender_ident))
2345 if (errno == 0 || errno == ENOENT)
2347 HDEBUG(D_receive) debug_printf("tcp wrappers rejection\n");
2348 log_write(L_connection_reject,
2349 LOG_MAIN|LOG_REJECT, "refused connection from %s "
2350 "(tcp wrappers)", host_and_ident(FALSE));
2351 smtp_printf("554 SMTP service not available\r\n");
2355 int save_errno = errno;
2356 HDEBUG(D_receive) debug_printf("tcp wrappers rejected with unexpected "
2357 "errno value %d\n", save_errno);
2358 log_write(L_connection_reject,
2359 LOG_MAIN|LOG_REJECT, "temporarily refused connection from %s "
2360 "(tcp wrappers errno=%d)", host_and_ident(FALSE), save_errno);
2361 smtp_printf("451 Temporary local problem - please try later\r\n");
2367 /* Check for reserved slots. The value of smtp_accept_count has already been
2368 incremented to include this process. */
2370 if (smtp_accept_max > 0 &&
2371 smtp_accept_count > smtp_accept_max - smtp_accept_reserve)
2373 if ((rc = verify_check_host(&smtp_reserve_hosts)) != OK)
2375 log_write(L_connection_reject,
2376 LOG_MAIN, "temporarily refused connection from %s: not in "
2377 "reserve list: connected=%d max=%d reserve=%d%s",
2378 host_and_ident(FALSE), smtp_accept_count - 1, smtp_accept_max,
2379 smtp_accept_reserve, (rc == DEFER)? " (lookup deferred)" : "");
2380 smtp_printf("421 %s: Too many concurrent SMTP connections; "
2381 "please try again later\r\n", smtp_active_hostname);
2384 reserved_host = TRUE;
2387 /* If a load level above which only messages from reserved hosts are
2388 accepted is set, check the load. For incoming calls via the daemon, the
2389 check is done in the superior process if there are no reserved hosts, to
2390 save a fork. In all cases, the load average will already be available
2391 in a global variable at this point. */
2393 if (smtp_load_reserve >= 0 &&
2394 load_average > smtp_load_reserve &&
2396 verify_check_host(&smtp_reserve_hosts) != OK)
2398 log_write(L_connection_reject,
2399 LOG_MAIN, "temporarily refused connection from %s: not in "
2400 "reserve list and load average = %.2f", host_and_ident(FALSE),
2401 (double)load_average/1000.0);
2402 smtp_printf("421 %s: Too much load; please try again later\r\n",
2403 smtp_active_hostname);
2407 /* Determine whether unqualified senders or recipients are permitted
2408 for this host. Unfortunately, we have to do this every time, in order to
2409 set the flags so that they can be inspected when considering qualifying
2410 addresses in the headers. For a site that permits no qualification, this
2411 won't take long, however. */
2413 allow_unqualified_sender =
2414 verify_check_host(&sender_unqualified_hosts) == OK;
2416 allow_unqualified_recipient =
2417 verify_check_host(&recipient_unqualified_hosts) == OK;
2419 /* Determine whether HELO/EHLO is required for this host. The requirement
2420 can be hard or soft. */
2422 helo_required = verify_check_host(&helo_verify_hosts) == OK;
2424 helo_verify = verify_check_host(&helo_try_verify_hosts) == OK;
2426 /* Determine whether this hosts is permitted to send syntactic junk
2427 after a HELO or EHLO command. */
2429 helo_accept_junk = verify_check_host(&helo_accept_junk_hosts) == OK;
2432 /* For batch SMTP input we are now done. */
2434 if (smtp_batched_input) return TRUE;
2436 #ifdef SUPPORT_PROXY
2437 /* If valid Proxy Protocol source is connecting, set up session.
2438 * Failure will not allow any SMTP function other than QUIT. */
2439 proxy_session = FALSE;
2440 proxy_session_failed = FALSE;
2441 if (check_proxy_protocol_host())
2443 if (setup_proxy_protocol_host() == FALSE)
2445 proxy_session_failed = TRUE;
2447 debug_printf("Failure to extract proxied host, only QUIT allowed\n");
2451 sender_host_name = NULL;
2452 (void)host_name_lookup();
2453 host_build_sender_fullhost();
2458 /* Run the ACL if it exists */
2461 if (acl_smtp_connect != NULL)
2464 rc = acl_check(ACL_WHERE_CONNECT, NULL, acl_smtp_connect, &user_msg,
2468 (void)smtp_handle_acl_fail(ACL_WHERE_CONNECT, rc, user_msg, log_msg);
2473 /* Output the initial message for a two-way SMTP connection. It may contain
2474 newlines, which then cause a multi-line response to be given. */
2476 code = US"220"; /* Default status code */
2477 esc = US""; /* Default extended status code */
2478 esclen = 0; /* Length of esc */
2482 if (!(s = expand_string(smtp_banner)))
2483 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "Expansion of \"%s\" (smtp_banner) "
2484 "failed: %s", smtp_banner, expand_string_message);
2490 smtp_message_code(&code, &codelen, &s, NULL, TRUE);
2494 esclen = codelen - 4;
2498 /* Remove any terminating newlines; might as well remove trailing space too */
2501 while (p > s && isspace(p[-1])) p--;
2504 /* It seems that CC:Mail is braindead, and assumes that the greeting message
2505 is all contained in a single IP packet. The original code wrote out the
2506 greeting using several calls to fprint/fputc, and on busy servers this could
2507 cause it to be split over more than one packet - which caused CC:Mail to fall
2508 over when it got the second part of the greeting after sending its first
2509 command. Sigh. To try to avoid this, build the complete greeting message
2510 first, and output it in one fell swoop. This gives a better chance of it
2511 ending up as a single packet. */
2513 ss = store_get(size);
2517 do /* At least once, in case we have an empty string */
2520 uschar *linebreak = Ustrchr(p, '\n');
2521 ss = string_catn(ss, &size, &ptr, code, 3);
2522 if (linebreak == NULL)
2525 ss = string_catn(ss, &size, &ptr, US" ", 1);
2529 len = linebreak - p;
2530 ss = string_catn(ss, &size, &ptr, US"-", 1);
2532 ss = string_catn(ss, &size, &ptr, esc, esclen);
2533 ss = string_catn(ss, &size, &ptr, p, len);
2534 ss = string_catn(ss, &size, &ptr, US"\r\n", 2);
2536 if (linebreak != NULL) p++;
2540 ss[ptr] = 0; /* string_cat leaves room for this */
2542 /* Before we write the banner, check that there is no input pending, unless
2543 this synchronisation check is disabled. */
2547 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP protocol "
2548 "synchronization error (input sent without waiting for greeting): "
2549 "rejected connection from %s input=\"%s\"", host_and_ident(TRUE),
2550 string_printing(smtp_inptr));
2551 smtp_printf("554 SMTP synchronization error\r\n");
2555 /* Now output the banner */
2557 smtp_printf("%s", ss);
2565 /*************************************************
2566 * Handle SMTP syntax and protocol errors *
2567 *************************************************/
2569 /* Write to the log for SMTP syntax errors in incoming commands, if configured
2570 to do so. Then transmit the error response. The return value depends on the
2571 number of syntax and protocol errors in this SMTP session.
2574 type error type, given as a log flag bit
2575 code response code; <= 0 means don't send a response
2576 data data to reflect in the response (can be NULL)
2577 errmess the error message
2579 Returns: -1 limit of syntax/protocol errors NOT exceeded
2580 +1 limit of syntax/protocol errors IS exceeded
2582 These values fit in with the values of the "done" variable in the main
2583 processing loop in smtp_setup_msg(). */
2586 synprot_error(int type, int code, uschar *data, uschar *errmess)
2590 log_write(type, LOG_MAIN, "SMTP %s error in \"%s\" %s %s",
2591 (type == L_smtp_syntax_error)? "syntax" : "protocol",
2592 string_printing(smtp_cmd_buffer), host_and_ident(TRUE), errmess);
2594 if (++synprot_error_count > smtp_max_synprot_errors)
2597 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
2598 "syntax or protocol errors (last command was \"%s\")",
2599 host_and_ident(FALSE), string_printing(smtp_cmd_buffer));
2604 smtp_printf("%d%c%s%s%s\r\n", code, (yield == 1)? '-' : ' ',
2605 (data == NULL)? US"" : data, (data == NULL)? US"" : US": ", errmess);
2607 smtp_printf("%d Too many syntax or protocol errors\r\n", code);
2616 /*************************************************
2617 * Log incomplete transactions *
2618 *************************************************/
2620 /* This function is called after a transaction has been aborted by RSET, QUIT,
2621 connection drops or other errors. It logs the envelope information received
2622 so far in order to preserve address verification attempts.
2624 Argument: string to indicate what aborted the transaction
2629 incomplete_transaction_log(uschar *what)
2631 if (sender_address == NULL || /* No transaction in progress */
2632 !LOGGING(smtp_incomplete_transaction))
2635 /* Build list of recipients for logging */
2637 if (recipients_count > 0)
2640 raw_recipients = store_get(recipients_count * sizeof(uschar *));
2641 for (i = 0; i < recipients_count; i++)
2642 raw_recipients[i] = recipients_list[i].address;
2643 raw_recipients_count = recipients_count;
2646 log_write(L_smtp_incomplete_transaction, LOG_MAIN|LOG_SENDER|LOG_RECIPIENTS,
2647 "%s incomplete transaction (%s)", host_and_ident(TRUE), what);
2653 /*************************************************
2654 * Send SMTP response, possibly multiline *
2655 *************************************************/
2657 /* There are, it seems, broken clients out there that cannot handle multiline
2658 responses. If no_multiline_responses is TRUE (it can be set from an ACL), we
2659 output nothing for non-final calls, and only the first line for anything else.
2662 code SMTP code, may involve extended status codes
2663 codelen length of smtp code; if > 4 there's an ESC
2664 final FALSE if the last line isn't the final line
2665 msg message text, possibly containing newlines
2671 smtp_respond(uschar* code, int codelen, BOOL final, uschar *msg)
2676 if (!final && no_multiline_responses) return;
2681 esclen = codelen - 4;
2684 /* If this is the first output for a (non-batch) RCPT command, see if all RCPTs
2685 have had the same. Note: this code is also present in smtp_printf(). It would
2686 be tidier to have it only in one place, but when it was added, it was easier to
2687 do it that way, so as not to have to mess with the code for the RCPT command,
2688 which sometimes uses smtp_printf() and sometimes smtp_respond(). */
2690 if (rcpt_in_progress)
2692 if (rcpt_smtp_response == NULL)
2693 rcpt_smtp_response = string_copy(msg);
2694 else if (rcpt_smtp_response_same &&
2695 Ustrcmp(rcpt_smtp_response, msg) != 0)
2696 rcpt_smtp_response_same = FALSE;
2697 rcpt_in_progress = FALSE;
2700 /* Not output the message, splitting it up into multiple lines if necessary. */
2704 uschar *nl = Ustrchr(msg, '\n');
2707 smtp_printf("%.3s%c%.*s%s\r\n", code, final? ' ':'-', esclen, esc, msg);
2710 else if (nl[1] == 0 || no_multiline_responses)
2712 smtp_printf("%.3s%c%.*s%.*s\r\n", code, final? ' ':'-', esclen, esc,
2713 (int)(nl - msg), msg);
2718 smtp_printf("%.3s-%.*s%.*s\r\n", code, esclen, esc, (int)(nl - msg), msg);
2720 while (isspace(*msg)) msg++;
2728 /*************************************************
2729 * Parse user SMTP message *
2730 *************************************************/
2732 /* This function allows for user messages overriding the response code details
2733 by providing a suitable response code string at the start of the message
2734 user_msg. Check the message for starting with a response code and optionally an
2735 extended status code. If found, check that the first digit is valid, and if so,
2736 change the code pointer and length to use the replacement. An invalid code
2737 causes a panic log; in this case, if the log messages is the same as the user
2738 message, we must also adjust the value of the log message to show the code that
2739 is actually going to be used (the original one).
2741 This function is global because it is called from receive.c as well as within
2744 Note that the code length returned includes the terminating whitespace
2745 character, which is always included in the regex match.
2748 code SMTP code, may involve extended status codes
2749 codelen length of smtp code; if > 4 there's an ESC
2751 log_msg optional log message, to be adjusted with the new SMTP code
2752 check_valid if true, verify the response code
2758 smtp_message_code(uschar **code, int *codelen, uschar **msg, uschar **log_msg,
2764 if (!msg || !*msg) return;
2766 if ((n = pcre_exec(regex_smtp_code, NULL, CS *msg, Ustrlen(*msg), 0,
2767 PCRE_EOPT, ovector, sizeof(ovector)/sizeof(int))) < 0) return;
2769 if (check_valid && (*msg)[0] != (*code)[0])
2771 log_write(0, LOG_MAIN|LOG_PANIC, "configured error code starts with "
2772 "incorrect digit (expected %c) in \"%s\"", (*code)[0], *msg);
2773 if (log_msg != NULL && *log_msg == *msg)
2774 *log_msg = string_sprintf("%s %s", *code, *log_msg + ovector[1]);
2779 *codelen = ovector[1]; /* Includes final space */
2781 *msg += ovector[1]; /* Chop the code off the message */
2788 /*************************************************
2789 * Handle an ACL failure *
2790 *************************************************/
2792 /* This function is called when acl_check() fails. As well as calls from within
2793 this module, it is called from receive.c for an ACL after DATA. It sorts out
2794 logging the incident, and sets up the error response. A message containing
2795 newlines is turned into a multiline SMTP response, but for logging, only the
2798 There's a table of default permanent failure response codes to use in
2799 globals.c, along with the table of names. VFRY is special. Despite RFC1123 it
2800 defaults disabled in Exim. However, discussion in connection with RFC 821bis
2801 (aka RFC 2821) has concluded that the response should be 252 in the disabled
2802 state, because there are broken clients that try VRFY before RCPT. A 5xx
2803 response should be given only when the address is positively known to be
2804 undeliverable. Sigh. We return 252 if there is no VRFY ACL or it provides
2805 no explicit code, but if there is one we let it know best.
2806 Also, for ETRN, 458 is given on refusal, and for AUTH, 503.
2808 From Exim 4.63, it is possible to override the response code details by
2809 providing a suitable response code string at the start of the message provided
2810 in user_msg. The code's first digit is checked for validity.
2813 where where the ACL was called from
2815 user_msg a message that can be included in an SMTP response
2816 log_msg a message for logging
2818 Returns: 0 in most cases
2819 2 if the failure code was FAIL_DROP, in which case the
2820 SMTP connection should be dropped (this value fits with the
2821 "done" variable in smtp_setup_msg() below)
2825 smtp_handle_acl_fail(int where, int rc, uschar *user_msg, uschar *log_msg)
2827 BOOL drop = rc == FAIL_DROP;
2831 uschar *sender_info = US"";
2833 #ifdef WITH_CONTENT_SCAN
2834 (where == ACL_WHERE_MIME)? US"during MIME ACL checks" :
2836 (where == ACL_WHERE_PREDATA)? US"DATA" :
2837 (where == ACL_WHERE_DATA)? US"after DATA" :
2838 #ifndef DISABLE_PRDR
2839 (where == ACL_WHERE_PRDR)? US"after DATA PRDR" :
2841 (smtp_cmd_data == NULL)?
2842 string_sprintf("%s in \"connect\" ACL", acl_wherenames[where]) :
2843 string_sprintf("%s %s", acl_wherenames[where], smtp_cmd_data);
2845 if (drop) rc = FAIL;
2847 /* Set the default SMTP code, and allow a user message to change it. */
2849 smtp_code = rc == FAIL ? acl_wherecodes[where] : US"451";
2850 smtp_message_code(&smtp_code, &codelen, &user_msg, &log_msg,
2851 where != ACL_WHERE_VRFY);
2853 /* We used to have sender_address here; however, there was a bug that was not
2854 updating sender_address after a rewrite during a verify. When this bug was
2855 fixed, sender_address at this point became the rewritten address. I'm not sure
2856 this is what should be logged, so I've changed to logging the unrewritten
2857 address to retain backward compatibility. */
2859 #ifndef WITH_CONTENT_SCAN
2860 if (where == ACL_WHERE_RCPT || where == ACL_WHERE_DATA)
2862 if (where == ACL_WHERE_RCPT || where == ACL_WHERE_DATA || where == ACL_WHERE_MIME)
2865 sender_info = string_sprintf("F=<%s>%s%s%s%s ",
2866 sender_address_unrewritten ? sender_address_unrewritten : sender_address,
2867 sender_host_authenticated ? US" A=" : US"",
2868 sender_host_authenticated ? sender_host_authenticated : US"",
2869 sender_host_authenticated && authenticated_id ? US":" : US"",
2870 sender_host_authenticated && authenticated_id ? authenticated_id : US""
2874 /* If there's been a sender verification failure with a specific message, and
2875 we have not sent a response about it yet, do so now, as a preliminary line for
2876 failures, but not defers. However, always log it for defer, and log it for fail
2877 unless the sender_verify_fail log selector has been turned off. */
2879 if (sender_verified_failed != NULL &&
2880 !testflag(sender_verified_failed, af_sverify_told))
2882 BOOL save_rcpt_in_progress = rcpt_in_progress;
2883 rcpt_in_progress = FALSE; /* So as not to treat these as the error */
2885 setflag(sender_verified_failed, af_sverify_told);
2887 if (rc != FAIL || LOGGING(sender_verify_fail))
2888 log_write(0, LOG_MAIN|LOG_REJECT, "%s sender verify %s for <%s>%s",
2889 host_and_ident(TRUE),
2890 ((sender_verified_failed->special_action & 255) == DEFER)? "defer":"fail",
2891 sender_verified_failed->address,
2892 (sender_verified_failed->message == NULL)? US"" :
2893 string_sprintf(": %s", sender_verified_failed->message));
2895 if (rc == FAIL && sender_verified_failed->user_message != NULL)
2896 smtp_respond(smtp_code, codelen, FALSE, string_sprintf(
2897 testflag(sender_verified_failed, af_verify_pmfail)?
2898 "Postmaster verification failed while checking <%s>\n%s\n"
2899 "Several RFCs state that you are required to have a postmaster\n"
2900 "mailbox for each mail domain. This host does not accept mail\n"
2901 "from domains whose servers reject the postmaster address."
2903 testflag(sender_verified_failed, af_verify_nsfail)?
2904 "Callback setup failed while verifying <%s>\n%s\n"
2905 "The initial connection, or a HELO or MAIL FROM:<> command was\n"
2906 "rejected. Refusing MAIL FROM:<> does not help fight spam, disregards\n"
2907 "RFC requirements, and stops you from receiving standard bounce\n"
2908 "messages. This host does not accept mail from domains whose servers\n"
2911 "Verification failed for <%s>\n%s",
2912 sender_verified_failed->address,
2913 sender_verified_failed->user_message));
2915 rcpt_in_progress = save_rcpt_in_progress;
2918 /* Sort out text for logging */
2920 log_msg = (log_msg == NULL)? US"" : string_sprintf(": %s", log_msg);
2921 lognl = Ustrchr(log_msg, '\n');
2922 if (lognl != NULL) *lognl = 0;
2924 /* Send permanent failure response to the command, but the code used isn't
2925 always a 5xx one - see comments at the start of this function. If the original
2926 rc was FAIL_DROP we drop the connection and yield 2. */
2928 if (rc == FAIL) smtp_respond(smtp_code, codelen, TRUE, (user_msg == NULL)?
2929 US"Administrative prohibition" : user_msg);
2931 /* Send temporary failure response to the command. Don't give any details,
2932 unless acl_temp_details is set. This is TRUE for a callout defer, a "defer"
2933 verb, and for a header verify when smtp_return_error_details is set.
2935 This conditional logic is all somewhat of a mess because of the odd
2936 interactions between temp_details and return_error_details. One day it should
2937 be re-implemented in a tidier fashion. */
2941 if (acl_temp_details && user_msg != NULL)
2943 if (smtp_return_error_details &&
2944 sender_verified_failed != NULL &&
2945 sender_verified_failed->message != NULL)
2947 smtp_respond(smtp_code, codelen, FALSE, sender_verified_failed->message);
2949 smtp_respond(smtp_code, codelen, TRUE, user_msg);
2952 smtp_respond(smtp_code, codelen, TRUE,
2953 US"Temporary local problem - please try later");
2956 /* Log the incident to the logs that are specified by log_reject_target
2957 (default main, reject). This can be empty to suppress logging of rejections. If
2958 the connection is not forcibly to be dropped, return 0. Otherwise, log why it
2959 is closing if required and return 2. */
2961 if (log_reject_target != 0)
2964 uschar * tls = s_tlslog(NULL, NULL, NULL);
2965 if (!tls) tls = US"";
2967 uschar * tls = US"";
2969 log_write(0, log_reject_target, "%s%s%s %s%srejected %s%s",
2970 LOGGING(dnssec) && sender_host_dnssec ? US" DS" : US"",
2971 host_and_ident(TRUE),
2974 rc == FAIL ? US"" : US"temporarily ",
2978 if (!drop) return 0;
2980 log_write(L_smtp_connection, LOG_MAIN, "%s closed by DROP in ACL",
2981 smtp_get_connection_info());
2983 /* Run the not-quit ACL, but without any custom messages. This should not be a
2984 problem, because we get here only if some other ACL has issued "drop", and
2985 in that case, *its* custom messages will have been used above. */
2987 smtp_notquit_exit(US"acl-drop", NULL, NULL);
2994 /*************************************************
2995 * Handle SMTP exit when QUIT is not given *
2996 *************************************************/
2998 /* This function provides a logging/statistics hook for when an SMTP connection
2999 is dropped on the floor or the other end goes away. It's a global function
3000 because it's called from receive.c as well as this module. As well as running
3001 the NOTQUIT ACL, if there is one, this function also outputs a final SMTP
3002 response, either with a custom message from the ACL, or using a default. There
3003 is one case, however, when no message is output - after "drop". In that case,
3004 the ACL that obeyed "drop" has already supplied the custom message, and NULL is
3005 passed to this function.
3007 In case things go wrong while processing this function, causing an error that
3008 may re-enter this funtion, there is a recursion check.
3011 reason What $smtp_notquit_reason will be set to in the ACL;
3012 if NULL, the ACL is not run
3013 code The error code to return as part of the response
3014 defaultrespond The default message if there's no user_msg
3020 smtp_notquit_exit(uschar *reason, uschar *code, uschar *defaultrespond, ...)
3023 uschar *user_msg = NULL;
3024 uschar *log_msg = NULL;
3026 /* Check for recursive acll */
3028 if (smtp_exit_function_called)
3030 log_write(0, LOG_PANIC, "smtp_notquit_exit() called more than once (%s)",
3034 smtp_exit_function_called = TRUE;
3036 /* Call the not-QUIT ACL, if there is one, unless no reason is given. */
3038 if (acl_smtp_notquit != NULL && reason != NULL)
3040 smtp_notquit_reason = reason;
3041 rc = acl_check(ACL_WHERE_NOTQUIT, NULL, acl_smtp_notquit, &user_msg,
3044 log_write(0, LOG_MAIN|LOG_PANIC, "ACL for not-QUIT returned ERROR: %s",
3048 /* Write an SMTP response if we are expected to give one. As the default
3049 responses are all internal, they should always fit in the buffer, but code a
3050 warning, just in case. Note that string_vformat() still leaves a complete
3051 string, even if it is incomplete. */
3053 if (code != NULL && defaultrespond != NULL)
3055 if (user_msg == NULL)
3059 va_start(ap, defaultrespond);
3060 if (!string_vformat(buffer, sizeof(buffer), CS defaultrespond, ap))
3061 log_write(0, LOG_MAIN|LOG_PANIC, "string too large in smtp_notquit_exit()");
3062 smtp_printf("%s %s\r\n", code, buffer);
3066 smtp_respond(code, 3, TRUE, user_msg);
3074 /*************************************************
3075 * Verify HELO argument *
3076 *************************************************/
3078 /* This function is called if helo_verify_hosts or helo_try_verify_hosts is
3079 matched. It is also called from ACL processing if verify = helo is used and
3080 verification was not previously tried (i.e. helo_try_verify_hosts was not
3081 matched). The result of its processing is to set helo_verified and
3082 helo_verify_failed. These variables should both be FALSE for this function to
3085 Note that EHLO/HELO is legitimately allowed to quote an address literal. Allow
3086 for IPv6 ::ffff: literals.
3089 Returns: TRUE if testing was completed;
3090 FALSE on a temporary failure
3094 smtp_verify_helo(void)
3098 HDEBUG(D_receive) debug_printf("verifying EHLO/HELO argument \"%s\"\n",
3101 if (sender_helo_name == NULL)
3103 HDEBUG(D_receive) debug_printf("no EHLO/HELO command was issued\n");
3106 /* Deal with the case of -bs without an IP address */
3108 else if (sender_host_address == NULL)
3110 HDEBUG(D_receive) debug_printf("no client IP address: assume success\n");
3111 helo_verified = TRUE;
3114 /* Deal with the more common case when there is a sending IP address */
3116 else if (sender_helo_name[0] == '[')
3118 helo_verified = Ustrncmp(sender_helo_name+1, sender_host_address,
3119 Ustrlen(sender_host_address)) == 0;
3124 if (strncmpic(sender_host_address, US"::ffff:", 7) == 0)
3125 helo_verified = Ustrncmp(sender_helo_name + 1,
3126 sender_host_address + 7, Ustrlen(sender_host_address) - 7) == 0;
3131 { if (helo_verified) debug_printf("matched host address\n"); }
3134 /* Do a reverse lookup if one hasn't already given a positive or negative
3135 response. If that fails, or the name doesn't match, try checking with a forward
3140 if (sender_host_name == NULL && !host_lookup_failed)
3141 yield = host_name_lookup() != DEFER;
3143 /* If a host name is known, check it and all its aliases. */
3145 if (sender_host_name)
3146 if ((helo_verified = strcmpic(sender_host_name, sender_helo_name) == 0))
3148 sender_helo_dnssec = sender_host_dnssec;
3149 HDEBUG(D_receive) debug_printf("matched host name\n");
3153 uschar **aliases = sender_host_aliases;
3155 if ((helo_verified = strcmpic(*aliases++, sender_helo_name) == 0))
3157 sender_helo_dnssec = sender_host_dnssec;
3161 HDEBUG(D_receive) if (helo_verified)
3162 debug_printf("matched alias %s\n", *(--aliases));
3165 /* Final attempt: try a forward lookup of the helo name */
3174 h.name = sender_helo_name;
3181 HDEBUG(D_receive) debug_printf("getting IP address for %s\n",
3183 rc = host_find_bydns(&h, NULL, HOST_FIND_BY_A,
3184 NULL, NULL, NULL, &d, NULL, NULL);
3185 if (rc == HOST_FOUND || rc == HOST_FOUND_LOCAL)
3186 for (hh = &h; hh; hh = hh->next)
3187 if (Ustrcmp(hh->address, sender_host_address) == 0)
3189 helo_verified = TRUE;
3190 if (h.dnssec == DS_YES) sender_helo_dnssec = TRUE;
3193 debug_printf("IP address for %s matches calling address\n"
3194 "Forward DNS security status: %sverified\n",
3195 sender_helo_name, sender_helo_dnssec ? "" : "un");
3202 if (!helo_verified) helo_verify_failed = TRUE; /* We've tried ... */
3209 /*************************************************
3210 * Send user response message *
3211 *************************************************/
3213 /* This function is passed a default response code and a user message. It calls
3214 smtp_message_code() to check and possibly modify the response code, and then
3215 calls smtp_respond() to transmit the response. I put this into a function
3216 just to avoid a lot of repetition.
3219 code the response code
3220 user_msg the user message
3226 smtp_user_msg(uschar *code, uschar *user_msg)
3229 smtp_message_code(&code, &len, &user_msg, NULL, TRUE);
3230 smtp_respond(code, len, TRUE, user_msg);
3236 smtp_in_auth(auth_instance *au, uschar ** s, uschar ** ss)
3238 const uschar *set_id = NULL;
3241 /* Run the checking code, passing the remainder of the command line as
3242 data. Initials the $auth<n> variables as empty. Initialize $0 empty and set
3243 it as the only set numerical variable. The authenticator may set $auth<n>
3244 and also set other numeric variables. The $auth<n> variables are preferred
3245 nowadays; the numerical variables remain for backwards compatibility.
3247 Afterwards, have a go at expanding the set_id string, even if
3248 authentication failed - for bad passwords it can be useful to log the
3249 userid. On success, require set_id to expand and exist, and put it in
3250 authenticated_id. Save this in permanent store, as the working store gets
3251 reset at HELO, RSET, etc. */
3253 for (i = 0; i < AUTH_VARS; i++) auth_vars[i] = NULL;
3255 expand_nlength[0] = 0; /* $0 contains nothing */
3257 rc = (au->info->servercode)(au, smtp_cmd_data);
3258 if (au->set_id) set_id = expand_string(au->set_id);
3259 expand_nmax = -1; /* Reset numeric variables */
3260 for (i = 0; i < AUTH_VARS; i++) auth_vars[i] = NULL; /* Reset $auth<n> */
3262 /* The value of authenticated_id is stored in the spool file and printed in
3263 log lines. It must not contain binary zeros or newline characters. In
3264 normal use, it never will, but when playing around or testing, this error
3265 can (did) happen. To guard against this, ensure that the id contains only
3266 printing characters. */
3268 if (set_id) set_id = string_printing(set_id);
3270 /* For the non-OK cases, set up additional logging data if set_id
3274 set_id = set_id && *set_id
3275 ? string_sprintf(" (set_id=%s)", set_id) : US"";
3277 /* Switch on the result */
3282 if (!au->set_id || set_id) /* Complete success */
3284 if (set_id) authenticated_id = string_copy_malloc(set_id);
3285 sender_host_authenticated = au->name;
3286 authentication_failed = FALSE;
3287 authenticated_fail_id = NULL; /* Impossible to already be set? */
3290 (sender_host_address ? protocols : protocols_local)
3291 [pextend + pauthed + (tls_in.active >= 0 ? pcrpted:0)];
3292 *s = *ss = US"235 Authentication succeeded";
3293 authenticated_by = au;
3297 /* Authentication succeeded, but we failed to expand the set_id string.
3298 Treat this as a temporary error. */
3300 auth_defer_msg = expand_string_message;
3304 if (set_id) authenticated_fail_id = string_copy_malloc(set_id);
3305 *s = string_sprintf("435 Unable to authenticate at present%s",
3306 auth_defer_user_msg);
3307 *ss = string_sprintf("435 Unable to authenticate at present%s: %s",
3308 set_id, auth_defer_msg);
3312 *s = *ss = US"501 Invalid base64 data";
3316 *s = *ss = US"501 Authentication cancelled";
3320 *s = *ss = US"553 Initial data not expected";
3324 if (set_id) authenticated_fail_id = string_copy_malloc(set_id);
3325 *s = US"535 Incorrect authentication data";
3326 *ss = string_sprintf("535 Incorrect authentication data%s", set_id);
3330 if (set_id) authenticated_fail_id = string_copy_malloc(set_id);
3331 *s = US"435 Internal error";
3332 *ss = string_sprintf("435 Internal error%s: return %d from authentication "
3333 "check", set_id, rc);
3345 qualify_recipient(uschar ** recipient, uschar * smtp_cmd_data, uschar * tag)
3348 if (allow_unqualified_recipient || strcmpic(*recipient, US"postmaster") == 0)
3350 DEBUG(D_receive) debug_printf("unqualified address %s accepted\n",
3352 rd = Ustrlen(recipient) + 1;
3353 *recipient = rewrite_address_qualify(*recipient, TRUE);
3356 smtp_printf("501 %s: recipient address must contain a domain\r\n",
3358 log_write(L_smtp_syntax_error,
3359 LOG_MAIN|LOG_REJECT, "unqualified %s rejected: <%s> %s%s",
3360 tag, *recipient, host_and_ident(TRUE), host_lookup_msg);
3368 smtp_quit_handler(uschar ** user_msgp, uschar ** log_msgp)
3371 incomplete_transaction_log(US"QUIT");
3372 if (acl_smtp_quit != NULL)
3374 int rc = acl_check(ACL_WHERE_QUIT, NULL, acl_smtp_quit, user_msgp, log_msgp);
3376 log_write(0, LOG_MAIN|LOG_PANIC, "ACL for QUIT returned ERROR: %s",
3380 smtp_respond(US"221", 3, TRUE, *user_msgp);
3382 smtp_printf("221 %s closing connection\r\n", smtp_active_hostname);
3385 tls_close(TRUE, TRUE);
3388 log_write(L_smtp_connection, LOG_MAIN, "%s closed by QUIT",
3389 smtp_get_connection_info());
3394 smtp_rset_handler(void)
3397 incomplete_transaction_log(US"RSET");
3398 smtp_printf("250 Reset OK\r\n");
3399 cmd_list[CMD_LIST_RSET].is_mail_cmd = FALSE;
3404 /*************************************************
3405 * Initialize for SMTP incoming message *
3406 *************************************************/
3408 /* This function conducts the initial dialogue at the start of an incoming SMTP
3409 message, and builds a list of recipients. However, if the incoming message
3410 is part of a batch (-bS option) a separate function is called since it would
3411 be messy having tests splattered about all over this function. This function
3412 therefore handles the case where interaction is occurring. The input and output
3413 files are set up in smtp_in and smtp_out.
3415 The global recipients_list is set to point to a vector of recipient_item
3416 blocks, whose number is given by recipients_count. This is extended by the
3417 receive_add_recipient() function. The global variable sender_address is set to
3418 the sender's address. The yield is +1 if a message has been successfully
3419 started, 0 if a QUIT command was encountered or the connection was refused from
3420 the particular host, or -1 if the connection was lost.
3424 Returns: > 0 message successfully started (reached DATA)
3425 = 0 QUIT read or end of file reached or call refused
3430 smtp_setup_msg(void)
3433 BOOL toomany = FALSE;
3434 BOOL discarded = FALSE;
3435 BOOL last_was_rej_mail = FALSE;
3436 BOOL last_was_rcpt = FALSE;
3437 void *reset_point = store_get(0);
3439 DEBUG(D_receive) debug_printf("smtp_setup_msg entered\n");
3441 /* Reset for start of new message. We allow one RSET not to be counted as a
3442 nonmail command, for those MTAs that insist on sending it between every
3443 message. Ditto for EHLO/HELO and for STARTTLS, to allow for going in and out of
3444 TLS between messages (an Exim client may do this if it has messages queued up
3445 for the host). Note: we do NOT reset AUTH at this point. */
3447 smtp_reset(reset_point);
3448 message_ended = END_NOTSTARTED;
3450 chunking_state = chunking_offered ? CHUNKING_OFFERED : CHUNKING_NOT_OFFERED;
3452 cmd_list[CMD_LIST_RSET].is_mail_cmd = TRUE;
3453 cmd_list[CMD_LIST_HELO].is_mail_cmd = TRUE;
3454 cmd_list[CMD_LIST_EHLO].is_mail_cmd = TRUE;
3456 cmd_list[CMD_LIST_STARTTLS].is_mail_cmd = TRUE;
3457 cmd_list[CMD_LIST_TLS_AUTH].is_mail_cmd = TRUE;
3460 /* Set the local signal handler for SIGTERM - it tries to end off tidily */
3462 os_non_restarting_signal(SIGTERM, command_sigterm_handler);
3464 /* Batched SMTP is handled in a different function. */
3466 if (smtp_batched_input) return smtp_setup_batch_msg();
3468 /* Deal with SMTP commands. This loop is exited by setting done to a POSITIVE
3469 value. The values are 2 larger than the required yield of the function. */
3473 const uschar **argv;
3474 uschar *etrn_command;
3475 uschar *etrn_serialize_key;
3477 uschar *log_msg, *smtp_code;
3478 uschar *user_msg = NULL;
3479 uschar *recipient = NULL;
3480 uschar *hello = NULL;
3482 BOOL was_rej_mail = FALSE;
3483 BOOL was_rcpt = FALSE;
3484 void (*oldsignal)(int);
3486 int start, end, sender_domain, recipient_domain;
3490 uschar *orcpt = NULL;
3493 #if defined(SUPPORT_TLS) && defined(AUTH_TLS)
3494 /* Check once per STARTTLS or SSL-on-connect for a TLS AUTH */
3495 if ( tls_in.active >= 0
3497 && tls_in.certificate_verified
3498 && cmd_list[CMD_LIST_TLS_AUTH].is_mail_cmd
3501 cmd_list[CMD_LIST_TLS_AUTH].is_mail_cmd = FALSE;
3503 && (rc = acl_check(ACL_WHERE_AUTH, NULL, acl_smtp_auth,
3504 &user_msg, &log_msg)) != OK
3507 done = smtp_handle_acl_fail(ACL_WHERE_AUTH, rc, user_msg, log_msg);
3511 for (au = auths; au; au = au->next)
3512 if (strcmpic(US"tls", au->driver_name) == 0)
3514 smtp_cmd_data = NULL;
3516 if (smtp_in_auth(au, &s, &ss) == OK)
3517 { DEBUG(D_auth) debug_printf("tls auth succeeded\n"); }
3519 { DEBUG(D_auth) debug_printf("tls auth not succeeded\n"); }
3525 switch(smtp_read_command(TRUE))
3527 /* The AUTH command is not permitted to occur inside a transaction, and may
3528 occur successfully only once per connection. Actually, that isn't quite
3529 true. When TLS is started, all previous information about a connection must
3530 be discarded, so a new AUTH is permitted at that time.
3532 AUTH may only be used when it has been advertised. However, it seems that
3533 there are clients that send AUTH when it hasn't been advertised, some of
3534 them even doing this after HELO. And there are MTAs that accept this. Sigh.
3535 So there's a get-out that allows this to happen.
3537 AUTH is initially labelled as a "nonmail command" so that one occurrence
3538 doesn't get counted. We change the label here so that multiple failing
3539 AUTHS will eventually hit the nonmail threshold. */
3543 authentication_failed = TRUE;
3544 cmd_list[CMD_LIST_AUTH].is_mail_cmd = FALSE;
3546 if (!auth_advertised && !allow_auth_unadvertised)
3548 done = synprot_error(L_smtp_protocol_error, 503, NULL,
3549 US"AUTH command used when not advertised");
3552 if (sender_host_authenticated)
3554 done = synprot_error(L_smtp_protocol_error, 503, NULL,
3555 US"already authenticated");
3560 done = synprot_error(L_smtp_protocol_error, 503, NULL,
3561 US"not permitted in mail transaction");
3568 && (rc = acl_check(ACL_WHERE_AUTH, NULL, acl_smtp_auth,
3569 &user_msg, &log_msg)) != OK
3572 done = smtp_handle_acl_fail(ACL_WHERE_AUTH, rc, user_msg, log_msg);
3576 /* Find the name of the requested authentication mechanism. */
3579 while ((c = *smtp_cmd_data) != 0 && !isspace(c))
3581 if (!isalnum(c) && c != '-' && c != '_')
3583 done = synprot_error(L_smtp_syntax_error, 501, NULL,
3584 US"invalid character in authentication mechanism name");
3590 /* If not at the end of the line, we must be at white space. Terminate the
3591 name and move the pointer on to any data that may be present. */
3593 if (*smtp_cmd_data != 0)
3595 *smtp_cmd_data++ = 0;
3596 while (isspace(*smtp_cmd_data)) smtp_cmd_data++;
3599 /* Search for an authentication mechanism which is configured for use
3600 as a server and which has been advertised (unless, sigh, allow_auth_
3601 unadvertised is set). */
3603 for (au = auths; au; au = au->next)
3604 if (strcmpic(s, au->public_name) == 0 && au->server &&
3605 (au->advertised || allow_auth_unadvertised))
3610 c = smtp_in_auth(au, &s, &ss);
3612 smtp_printf("%s\r\n", s);
3614 log_write(0, LOG_MAIN|LOG_REJECT, "%s authenticator failed for %s: %s",
3615 au->name, host_and_ident(FALSE), ss);
3618 done = synprot_error(L_smtp_protocol_error, 504, NULL,
3619 string_sprintf("%s authentication mechanism not supported", s));
3621 break; /* AUTH_CMD */
3623 /* The HELO/EHLO commands are permitted to appear in the middle of a
3624 session as well as at the beginning. They have the effect of a reset in
3625 addition to their other functions. Their absence at the start cannot be
3626 taken to be an error.
3630 If the EHLO command is not acceptable to the SMTP server, 501, 500,
3631 or 502 failure replies MUST be returned as appropriate. The SMTP
3632 server MUST stay in the same state after transmitting these replies
3633 that it was in before the EHLO was received.
3635 Therefore, we do not do the reset until after checking the command for
3636 acceptability. This change was made for Exim release 4.11. Previously
3637 it did the reset first. */
3650 HELO_EHLO: /* Common code for HELO and EHLO */
3651 cmd_list[CMD_LIST_HELO].is_mail_cmd = FALSE;
3652 cmd_list[CMD_LIST_EHLO].is_mail_cmd = FALSE;
3654 /* Reject the HELO if its argument was invalid or non-existent. A
3655 successful check causes the argument to be saved in malloc store. */
3657 if (!check_helo(smtp_cmd_data))
3659 smtp_printf("501 Syntactically invalid %s argument(s)\r\n", hello);
3661 log_write(0, LOG_MAIN|LOG_REJECT, "rejected %s from %s: syntactically "
3662 "invalid argument(s): %s", hello, host_and_ident(FALSE),
3663 (*smtp_cmd_argument == 0)? US"(no argument given)" :
3664 string_printing(smtp_cmd_argument));
3666 if (++synprot_error_count > smtp_max_synprot_errors)
3668 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
3669 "syntax or protocol errors (last command was \"%s\")",
3670 host_and_ident(FALSE), string_printing(smtp_cmd_buffer));
3677 /* If sender_host_unknown is true, we have got here via the -bs interface,
3678 not called from inetd. Otherwise, we are running an IP connection and the
3679 host address will be set. If the helo name is the primary name of this
3680 host and we haven't done a reverse lookup, force one now. If helo_required
3681 is set, ensure that the HELO name matches the actual host. If helo_verify
3682 is set, do the same check, but softly. */
3684 if (!sender_host_unknown)
3686 BOOL old_helo_verified = helo_verified;
3687 uschar *p = smtp_cmd_data;
3689 while (*p != 0 && !isspace(*p)) { *p = tolower(*p); p++; }
3692 /* Force a reverse lookup if HELO quoted something in helo_lookup_domains
3693 because otherwise the log can be confusing. */
3695 if (sender_host_name == NULL &&
3696 (deliver_domain = sender_helo_name, /* set $domain */
3697 match_isinlist(sender_helo_name, CUSS &helo_lookup_domains, 0,
3698 &domainlist_anchor, NULL, MCL_DOMAIN, TRUE, NULL)) == OK)
3699 (void)host_name_lookup();
3701 /* Rebuild the fullhost info to include the HELO name (and the real name
3702 if it was looked up.) */
3704 host_build_sender_fullhost(); /* Rebuild */
3705 set_process_info("handling%s incoming connection from %s",
3706 (tls_in.active >= 0)? " TLS" : "", host_and_ident(FALSE));
3708 /* Verify if configured. This doesn't give much security, but it does
3709 make some people happy to be able to do it. If helo_required is set,
3710 (host matches helo_verify_hosts) failure forces rejection. If helo_verify
3711 is set (host matches helo_try_verify_hosts), it does not. This is perhaps
3712 now obsolescent, since the verification can now be requested selectively
3715 helo_verified = helo_verify_failed = sender_helo_dnssec = FALSE;
3716 if (helo_required || helo_verify)
3718 BOOL tempfail = !smtp_verify_helo();
3723 smtp_printf("%d %s argument does not match calling host\r\n",
3724 tempfail? 451 : 550, hello);
3725 log_write(0, LOG_MAIN|LOG_REJECT, "%srejected \"%s %s\" from %s",
3726 tempfail? "temporarily " : "",
3727 hello, sender_helo_name, host_and_ident(FALSE));
3728 helo_verified = old_helo_verified;
3729 break; /* End of HELO/EHLO processing */
3731 HDEBUG(D_all) debug_printf("%s verification failed but host is in "
3732 "helo_try_verify_hosts\n", hello);
3737 #ifdef EXPERIMENTAL_SPF
3738 /* set up SPF context */
3739 spf_init(sender_helo_name, sender_host_address);
3742 /* Apply an ACL check if one is defined; afterwards, recheck
3743 synchronization in case the client started sending in a delay. */
3746 if ((rc = acl_check(ACL_WHERE_HELO, NULL, acl_smtp_helo,
3747 &user_msg, &log_msg)) != OK)
3749 done = smtp_handle_acl_fail(ACL_WHERE_HELO, rc, user_msg, log_msg);
3750 sender_helo_name = NULL;
3751 host_build_sender_fullhost(); /* Rebuild */
3754 else if (!check_sync()) goto SYNC_FAILURE;
3756 /* Generate an OK reply. The default string includes the ident if present,
3757 and also the IP address if present. Reflecting back the ident is intended
3758 as a deterrent to mail forgers. For maximum efficiency, and also because
3759 some broken systems expect each response to be in a single packet, arrange
3760 that the entire reply is sent in one write(). */
3762 auth_advertised = FALSE;
3763 pipelining_advertised = FALSE;
3765 tls_advertised = FALSE;
3767 dsn_advertised = FALSE;
3769 smtputf8_advertised = FALSE;
3772 smtp_code = US"250 "; /* Default response code plus space*/
3773 if (user_msg == NULL)
3775 s = string_sprintf("%.3s %s Hello %s%s%s",
3777 smtp_active_hostname,
3778 (sender_ident == NULL)? US"" : sender_ident,
3779 (sender_ident == NULL)? US"" : US" at ",
3780 (sender_host_name == NULL)? sender_helo_name : sender_host_name);
3785 if (sender_host_address != NULL)
3787 s = string_catn(s, &size, &ptr, US" [", 2);
3788 s = string_cat (s, &size, &ptr, sender_host_address);
3789 s = string_catn(s, &size, &ptr, US"]", 1);
3793 /* A user-supplied EHLO greeting may not contain more than one line. Note
3794 that the code returned by smtp_message_code() includes the terminating
3795 whitespace character. */
3801 smtp_message_code(&smtp_code, &codelen, &user_msg, NULL, TRUE);
3802 s = string_sprintf("%.*s%s", codelen, smtp_code, user_msg);
3803 if ((ss = strpbrk(CS s, "\r\n")) != NULL)
3805 log_write(0, LOG_MAIN|LOG_PANIC, "EHLO/HELO response must not contain "
3806 "newlines: message truncated: %s", string_printing(s));
3813 s = string_catn(s, &size, &ptr, US"\r\n", 2);
3815 /* If we received EHLO, we must create a multiline response which includes
3816 the functions supported. */
3822 /* I'm not entirely happy with this, as an MTA is supposed to check
3823 that it has enough room to accept a message of maximum size before
3824 it sends this. However, there seems little point in not sending it.
3825 The actual size check happens later at MAIL FROM time. By postponing it
3826 till then, VRFY and EXPN can be used after EHLO when space is short. */
3828 if (thismessage_size_limit > 0)
3830 sprintf(CS big_buffer, "%.3s-SIZE %d\r\n", smtp_code,
3831 thismessage_size_limit);
3832 s = string_cat(s, &size, &ptr, big_buffer);
3836 s = string_catn(s, &size, &ptr, smtp_code, 3);
3837 s = string_catn(s, &size, &ptr, US"-SIZE\r\n", 7);
3840 /* Exim does not do protocol conversion or data conversion. It is 8-bit
3841 clean; if it has an 8-bit character in its hand, it just sends it. It
3842 cannot therefore specify 8BITMIME and remain consistent with the RFCs.
3843 However, some users want this option simply in order to stop MUAs
3844 mangling messages that contain top-bit-set characters. It is therefore
3845 provided as an option. */
3847 if (accept_8bitmime)
3849 s = string_catn(s, &size, &ptr, smtp_code, 3);
3850 s = string_catn(s, &size, &ptr, US"-8BITMIME\r\n", 11);
3853 /* Advertise DSN support if configured to do so. */
3854 if (verify_check_host(&dsn_advertise_hosts) != FAIL)
3856 s = string_catn(s, &size, &ptr, smtp_code, 3);
3857 s = string_catn(s, &size, &ptr, US"-DSN\r\n", 6);
3858 dsn_advertised = TRUE;
3861 /* Advertise ETRN if there's an ACL checking whether a host is
3862 permitted to issue it; a check is made when any host actually tries. */
3864 if (acl_smtp_etrn != NULL)
3866 s = string_catn(s, &size, &ptr, smtp_code, 3);
3867 s = string_catn(s, &size, &ptr, US"-ETRN\r\n", 7);
3870 /* Advertise EXPN if there's an ACL checking whether a host is
3871 permitted to issue it; a check is made when any host actually tries. */
3873 if (acl_smtp_expn != NULL)
3875 s = string_catn(s, &size, &ptr, smtp_code, 3);
3876 s = string_catn(s, &size, &ptr, US"-EXPN\r\n", 7);
3879 /* Exim is quite happy with pipelining, so let the other end know that
3880 it is safe to use it, unless advertising is disabled. */
3882 if (pipelining_enable &&
3883 verify_check_host(&pipelining_advertise_hosts) == OK)
3885 s = string_catn(s, &size, &ptr, smtp_code, 3);
3886 s = string_catn(s, &size, &ptr, US"-PIPELINING\r\n", 13);
3887 sync_cmd_limit = NON_SYNC_CMD_PIPELINING;
3888 pipelining_advertised = TRUE;
3892 /* If any server authentication mechanisms are configured, advertise
3893 them if the current host is in auth_advertise_hosts. The problem with
3894 advertising always is that some clients then require users to
3895 authenticate (and aren't configurable otherwise) even though it may not
3896 be necessary (e.g. if the host is in host_accept_relay).
3898 RFC 2222 states that SASL mechanism names contain only upper case
3899 letters, so output the names in upper case, though we actually recognize
3900 them in either case in the AUTH command. */
3903 #if defined(SUPPORT_TLS) && defined(AUTH_TLS)
3904 && !sender_host_authenticated
3906 && verify_check_host(&auth_advertise_hosts) == OK
3911 for (au = auths; au; au = au->next)
3912 if (au->server && (au->advertise_condition == NULL ||
3913 expand_check_condition(au->advertise_condition, au->name,
3914 US"authenticator")))
3919 s = string_catn(s, &size, &ptr, smtp_code, 3);
3920 s = string_catn(s, &size, &ptr, US"-AUTH", 5);
3922 auth_advertised = TRUE;
3925 s = string_catn(s, &size, &ptr, US" ", 1);
3926 s = string_cat (s, &size, &ptr, au->public_name);
3927 while (++saveptr < ptr) s[saveptr] = toupper(s[saveptr]);
3928 au->advertised = TRUE;
3931 au->advertised = FALSE;
3933 if (!first) s = string_catn(s, &size, &ptr, US"\r\n", 2);
3936 /* RFC 3030 CHUNKING */
3938 if (verify_check_host(&chunking_advertise_hosts) != FAIL)
3940 s = string_catn(s, &size, &ptr, smtp_code, 3);
3941 s = string_catn(s, &size, &ptr, US"-CHUNKING\r\n", 11);
3942 chunking_offered = TRUE;
3943 chunking_state = CHUNKING_OFFERED;
3946 /* Advertise TLS (Transport Level Security) aka SSL (Secure Socket Layer)
3947 if it has been included in the binary, and the host matches
3948 tls_advertise_hosts. We must *not* advertise if we are already in a
3949 secure connection. */
3952 if (tls_in.active < 0 &&
3953 verify_check_host(&tls_advertise_hosts) != FAIL)
3955 s = string_catn(s, &size, &ptr, smtp_code, 3);
3956 s = string_catn(s, &size, &ptr, US"-STARTTLS\r\n", 11);
3957 tls_advertised = TRUE;
3961 #ifndef DISABLE_PRDR
3962 /* Per Recipient Data Response, draft by Eric A. Hall extending RFC */
3965 s = string_catn(s, &size, &ptr, smtp_code, 3);
3966 s = string_catn(s, &size, &ptr, US"-PRDR\r\n", 7);
3971 if ( accept_8bitmime
3972 && verify_check_host(&smtputf8_advertise_hosts) != FAIL)
3974 s = string_catn(s, &size, &ptr, smtp_code, 3);
3975 s = string_catn(s, &size, &ptr, US"-SMTPUTF8\r\n", 11);
3976 smtputf8_advertised = TRUE;
3980 /* Finish off the multiline reply with one that is always available. */
3982 s = string_catn(s, &size, &ptr, smtp_code, 3);
3983 s = string_catn(s, &size, &ptr, US" HELP\r\n", 7);
3986 /* Terminate the string (for debug), write it, and note that HELO/EHLO
3992 if (tls_in.active >= 0) (void)tls_write(TRUE, s, ptr); else
3996 int i = fwrite(s, 1, ptr, smtp_out); i = i; /* compiler quietening */
4001 while ((cr = Ustrchr(s, '\r')) != NULL) /* lose CRs */
4002 memmove(cr, cr + 1, (ptr--) - (cr - s));
4003 debug_printf("SMTP>> %s", s);
4007 /* Reset the protocol and the state, abandoning any previous message. */
4009 (sender_host_address ? protocols : protocols_local)
4011 ? pextend + (sender_host_authenticated ? pauthed : 0)
4013 + (tls_in.active >= 0 ? pcrpted : 0)
4015 smtp_reset(reset_point);
4017 break; /* HELO/EHLO */
4020 /* The MAIL command requires an address as an operand. All we do
4021 here is to parse it for syntactic correctness. The form "<>" is
4022 a special case which converts into an empty string. The start/end
4023 pointers in the original are not used further for this address, as
4024 it is the canonical extracted address which is all that is kept. */
4028 smtp_mailcmd_count++; /* Count for limit and ratelimit */
4029 was_rej_mail = TRUE; /* Reset if accepted */
4030 env_mail_type_t * mail_args; /* Sanity check & validate args */
4032 if (helo_required && !helo_seen)
4034 smtp_printf("503 HELO or EHLO required\r\n");
4035 log_write(0, LOG_MAIN|LOG_REJECT, "rejected MAIL from %s: no "
4036 "HELO/EHLO given", host_and_ident(FALSE));
4040 if (sender_address != NULL)
4042 done = synprot_error(L_smtp_protocol_error, 503, NULL,
4043 US"sender already given");
4047 if (smtp_cmd_data[0] == 0)
4049 done = synprot_error(L_smtp_protocol_error, 501, NULL,
4050 US"MAIL must have an address operand");
4054 /* Check to see if the limit for messages per connection would be
4055 exceeded by accepting further messages. */
4057 if (smtp_accept_max_per_connection > 0 &&
4058 smtp_mailcmd_count > smtp_accept_max_per_connection)
4060 smtp_printf("421 too many messages in this connection\r\n");
4061 log_write(0, LOG_MAIN|LOG_REJECT, "rejected MAIL command %s: too many "
4062 "messages in one connection", host_and_ident(TRUE));
4066 /* Reset for start of message - even if this is going to fail, we
4067 obviously need to throw away any previous data. */
4069 smtp_reset(reset_point);
4071 sender_data = recipient_data = NULL;
4073 /* Loop, checking for ESMTP additions to the MAIL FROM command. */
4077 uschar *name, *value, *end;
4078 unsigned long int size;
4079 BOOL arg_error = FALSE;
4081 if (!extract_option(&name, &value)) break;
4083 for (mail_args = env_mail_type_list;
4084 mail_args->value != ENV_MAIL_OPT_NULL;
4087 if (strcmpic(name, mail_args->name) == 0)
4089 if (mail_args->need_value && strcmpic(value, US"") == 0)
4092 switch(mail_args->value)
4094 /* Handle SIZE= by reading the value. We don't do the check till later,
4095 in order to be able to log the sender address on failure. */
4096 case ENV_MAIL_OPT_SIZE:
4097 if (((size = Ustrtoul(value, &end, 10)), *end == 0))
4099 if ((size == ULONG_MAX && errno == ERANGE) || size > INT_MAX)
4101 message_size = (int)size;
4107 /* If this session was initiated with EHLO and accept_8bitmime is set,
4108 Exim will have indicated that it supports the BODY=8BITMIME option. In
4109 fact, it does not support this according to the RFCs, in that it does not
4110 take any special action for forwarding messages containing 8-bit
4111 characters. That is why accept_8bitmime is not the default setting, but
4112 some sites want the action that is provided. We recognize both "8BITMIME"
4113 and "7BIT" as body types, but take no action. */
4114 case ENV_MAIL_OPT_BODY:
4115 if (accept_8bitmime) {
4116 if (strcmpic(value, US"8BITMIME") == 0)
4118 else if (strcmpic(value, US"7BIT") == 0)
4123 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4124 US"invalid data for BODY");
4127 DEBUG(D_receive) debug_printf("8BITMIME: %d\n", body_8bitmime);
4133 /* Handle the two DSN options, but only if configured to do so (which
4134 will have caused "DSN" to be given in the EHLO response). The code itself
4135 is included only if configured in at build time. */
4137 case ENV_MAIL_OPT_RET:
4140 /* Check if RET has already been set */
4143 synprot_error(L_smtp_syntax_error, 501, NULL,
4144 US"RET can be specified once only");
4147 dsn_ret = strcmpic(value, US"HDRS") == 0
4149 : strcmpic(value, US"FULL") == 0
4152 DEBUG(D_receive) debug_printf("DSN_RET: %d\n", dsn_ret);
4153 /* Check for invalid invalid value, and exit with error */
4156 synprot_error(L_smtp_syntax_error, 501, NULL,
4157 US"Value for RET is invalid");
4162 case ENV_MAIL_OPT_ENVID:
4165 /* Check if the dsn envid has been already set */
4166 if (dsn_envid != NULL)
4168 synprot_error(L_smtp_syntax_error, 501, NULL,
4169 US"ENVID can be specified once only");
4172 dsn_envid = string_copy(value);
4173 DEBUG(D_receive) debug_printf("DSN_ENVID: %s\n", dsn_envid);
4177 /* Handle the AUTH extension. If the value given is not "<>" and either
4178 the ACL says "yes" or there is no ACL but the sending host is
4179 authenticated, we set it up as the authenticated sender. However, if the
4180 authenticator set a condition to be tested, we ignore AUTH on MAIL unless
4181 the condition is met. The value of AUTH is an xtext, which means that +,
4182 = and cntrl chars are coded in hex; however "<>" is unaffected by this
4184 case ENV_MAIL_OPT_AUTH:
4185 if (Ustrcmp(value, "<>") != 0)
4190 if (auth_xtextdecode(value, &authenticated_sender) < 0)
4192 /* Put back terminator overrides for error message */
4195 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4196 US"invalid data for AUTH");
4199 if (acl_smtp_mailauth == NULL)
4201 ignore_msg = US"client not authenticated";
4202 rc = (sender_host_authenticated != NULL)? OK : FAIL;
4206 ignore_msg = US"rejected by ACL";
4207 rc = acl_check(ACL_WHERE_MAILAUTH, NULL, acl_smtp_mailauth,
4208 &user_msg, &log_msg);
4214 if (authenticated_by == NULL ||
4215 authenticated_by->mail_auth_condition == NULL ||
4216 expand_check_condition(authenticated_by->mail_auth_condition,
4217 authenticated_by->name, US"authenticator"))
4218 break; /* Accept the AUTH */
4220 ignore_msg = US"server_mail_auth_condition failed";
4221 if (authenticated_id != NULL)
4222 ignore_msg = string_sprintf("%s: authenticated ID=\"%s\"",
4223 ignore_msg, authenticated_id);
4228 authenticated_sender = NULL;
4229 log_write(0, LOG_MAIN, "ignoring AUTH=%s from %s (%s)",
4230 value, host_and_ident(TRUE), ignore_msg);
4233 /* Should only get DEFER or ERROR here. Put back terminator
4234 overrides for error message */
4239 (void)smtp_handle_acl_fail(ACL_WHERE_MAILAUTH, rc, user_msg,
4246 #ifndef DISABLE_PRDR
4247 case ENV_MAIL_OPT_PRDR:
4249 prdr_requested = TRUE;
4254 case ENV_MAIL_OPT_UTF8:
4255 if (smtputf8_advertised)
4257 DEBUG(D_receive) debug_printf("smtputf8 requested\n");
4258 message_smtputf8 = allow_utf8_domains = TRUE;
4259 received_protocol = string_sprintf("utf8%s", received_protocol);
4263 /* No valid option. Stick back the terminator characters and break
4264 the loop. Do the name-terminator second as extract_option sets
4265 value==name when it found no equal-sign.
4266 An error for a malformed address will occur. */
4267 case ENV_MAIL_OPT_NULL:
4275 /* Break out of for loop if switch() had bad argument or
4276 when start of the email address is reached */
4277 if (arg_error) break;
4280 /* If we have passed the threshold for rate limiting, apply the current
4281 delay, and update it for next time, provided this is a limited host. */
4283 if (smtp_mailcmd_count > smtp_rlm_threshold &&
4284 verify_check_host(&smtp_ratelimit_hosts) == OK)
4286 DEBUG(D_receive) debug_printf("rate limit MAIL: delay %.3g sec\n",
4287 smtp_delay_mail/1000.0);
4288 millisleep((int)smtp_delay_mail);
4289 smtp_delay_mail *= smtp_rlm_factor;
4290 if (smtp_delay_mail > (double)smtp_rlm_limit)
4291 smtp_delay_mail = (double)smtp_rlm_limit;
4294 /* Now extract the address, first applying any SMTP-time rewriting. The
4295 TRUE flag allows "<>" as a sender address. */
4297 raw_sender = rewrite_existflags & rewrite_smtp
4298 ? rewrite_one(smtp_cmd_data, rewrite_smtp, NULL, FALSE, US"",
4299 global_rewrite_rules)
4303 parse_extract_address(raw_sender, &errmess, &start, &end, &sender_domain,
4308 done = synprot_error(L_smtp_syntax_error, 501, smtp_cmd_data, errmess);
4312 sender_address = raw_sender;
4314 /* If there is a configured size limit for mail, check that this message
4315 doesn't exceed it. The check is postponed to this point so that the sender
4318 if (thismessage_size_limit > 0 && message_size > thismessage_size_limit)
4320 smtp_printf("552 Message size exceeds maximum permitted\r\n");
4321 log_write(L_size_reject,
4322 LOG_MAIN|LOG_REJECT, "rejected MAIL FROM:<%s> %s: "
4323 "message too big: size%s=%d max=%d",
4325 host_and_ident(TRUE),
4326 (message_size == INT_MAX)? ">" : "",
4328 thismessage_size_limit);
4329 sender_address = NULL;
4333 /* Check there is enough space on the disk unless configured not to.
4334 When smtp_check_spool_space is set, the check is for thismessage_size_limit
4335 plus the current message - i.e. we accept the message only if it won't
4336 reduce the space below the threshold. Add 5000 to the size to allow for
4337 overheads such as the Received: line and storing of recipients, etc.
4338 By putting the check here, even when SIZE is not given, it allow VRFY
4339 and EXPN etc. to be used when space is short. */
4341 if (!receive_check_fs(
4342 (smtp_check_spool_space && message_size >= 0)?
4343 message_size + 5000 : 0))
4345 smtp_printf("452 Space shortage, please try later\r\n");
4346 sender_address = NULL;
4350 /* If sender_address is unqualified, reject it, unless this is a locally
4351 generated message, or the sending host or net is permitted to send
4352 unqualified addresses - typically local machines behaving as MUAs -
4353 in which case just qualify the address. The flag is set above at the start
4354 of the SMTP connection. */
4356 if (sender_domain == 0 && sender_address[0] != 0)
4358 if (allow_unqualified_sender)
4360 sender_domain = Ustrlen(sender_address) + 1;
4361 sender_address = rewrite_address_qualify(sender_address, FALSE);
4362 DEBUG(D_receive) debug_printf("unqualified address %s accepted\n",
4367 smtp_printf("501 %s: sender address must contain a domain\r\n",
4369 log_write(L_smtp_syntax_error,
4370 LOG_MAIN|LOG_REJECT,
4371 "unqualified sender rejected: <%s> %s%s",
4373 host_and_ident(TRUE),
4375 sender_address = NULL;
4380 /* Apply an ACL check if one is defined, before responding. Afterwards,
4381 when pipelining is not advertised, do another sync check in case the ACL
4382 delayed and the client started sending in the meantime. */
4386 rc = acl_check(ACL_WHERE_MAIL, NULL, acl_smtp_mail, &user_msg, &log_msg);
4387 if (rc == OK && !pipelining_advertised && !check_sync())
4393 if (rc == OK || rc == DISCARD)
4396 smtp_printf("%s%s%s", US"250 OK",
4397 #ifndef DISABLE_PRDR
4398 prdr_requested ? US", PRDR Requested" : US"",
4405 #ifndef DISABLE_PRDR
4407 user_msg = string_sprintf("%s%s", user_msg, US", PRDR Requested");
4409 smtp_user_msg(US"250", user_msg);
4411 smtp_delay_rcpt = smtp_rlr_base;
4412 recipients_discarded = (rc == DISCARD);
4413 was_rej_mail = FALSE;
4417 done = smtp_handle_acl_fail(ACL_WHERE_MAIL, rc, user_msg, log_msg);
4418 sender_address = NULL;
4423 /* The RCPT command requires an address as an operand. There may be any
4424 number of RCPT commands, specifying multiple recipients. We build them all
4425 into a data structure. The start/end values given by parse_extract_address
4426 are not used, as we keep only the extracted address. */
4431 was_rcpt = rcpt_in_progress = TRUE;
4433 /* There must be a sender address; if the sender was rejected and
4434 pipelining was advertised, we assume the client was pipelining, and do not
4435 count this as a protocol error. Reset was_rej_mail so that further RCPTs
4436 get the same treatment. */
4438 if (sender_address == NULL)
4440 if (pipelining_advertised && last_was_rej_mail)
4442 smtp_printf("503 sender not yet given\r\n");
4443 was_rej_mail = TRUE;
4447 done = synprot_error(L_smtp_protocol_error, 503, NULL,
4448 US"sender not yet given");
4449 was_rcpt = FALSE; /* Not a valid RCPT */
4455 /* Check for an operand */
4457 if (smtp_cmd_data[0] == 0)
4459 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4460 US"RCPT must have an address operand");
4465 /* Set the DSN flags orcpt and dsn_flags from the session*/
4471 uschar *name, *value;
4473 if (!extract_option(&name, &value))
4476 if (dsn_advertised && strcmpic(name, US"ORCPT") == 0)
4478 /* Check whether orcpt has been already set */
4481 synprot_error(L_smtp_syntax_error, 501, NULL,
4482 US"ORCPT can be specified once only");
4485 orcpt = string_copy(value);
4486 DEBUG(D_receive) debug_printf("DSN orcpt: %s\n", orcpt);
4489 else if (dsn_advertised && strcmpic(name, US"NOTIFY") == 0)
4491 /* Check if the notify flags have been already set */
4494 synprot_error(L_smtp_syntax_error, 501, NULL,
4495 US"NOTIFY can be specified once only");
4498 if (strcmpic(value, US"NEVER") == 0)
4499 flags |= rf_notify_never;
4506 while (*pp != 0 && *pp != ',') pp++;
4507 if (*pp == ',') *pp++ = 0;
4508 if (strcmpic(p, US"SUCCESS") == 0)
4510 DEBUG(D_receive) debug_printf("DSN: Setting notify success\n");
4511 flags |= rf_notify_success;
4513 else if (strcmpic(p, US"FAILURE") == 0)
4515 DEBUG(D_receive) debug_printf("DSN: Setting notify failure\n");
4516 flags |= rf_notify_failure;
4518 else if (strcmpic(p, US"DELAY") == 0)
4520 DEBUG(D_receive) debug_printf("DSN: Setting notify delay\n");
4521 flags |= rf_notify_delay;
4525 /* Catch any strange values */
4526 synprot_error(L_smtp_syntax_error, 501, NULL,
4527 US"Invalid value for NOTIFY parameter");
4532 DEBUG(D_receive) debug_printf("DSN Flags: %x\n", flags);
4536 /* Unknown option. Stick back the terminator characters and break
4537 the loop. An error for a malformed address will occur. */
4541 DEBUG(D_receive) debug_printf("Invalid RCPT option: %s : %s\n", name, value);
4548 /* Apply SMTP rewriting then extract the working address. Don't allow "<>"
4549 as a recipient address */
4551 recipient = rewrite_existflags & rewrite_smtp
4552 ? rewrite_one(smtp_cmd_data, rewrite_smtp, NULL, FALSE, US"",
4553 global_rewrite_rules)
4556 if (!(recipient = parse_extract_address(recipient, &errmess, &start, &end,
4557 &recipient_domain, FALSE)))
4559 done = synprot_error(L_smtp_syntax_error, 501, smtp_cmd_data, errmess);
4564 /* If the recipient address is unqualified, reject it, unless this is a
4565 locally generated message. However, unqualified addresses are permitted
4566 from a configured list of hosts and nets - typically when behaving as
4567 MUAs rather than MTAs. Sad that SMTP is used for both types of traffic,
4568 really. The flag is set at the start of the SMTP connection.
4570 RFC 1123 talks about supporting "the reserved mailbox postmaster"; I always
4571 assumed this meant "reserved local part", but the revision of RFC 821 and
4572 friends now makes it absolutely clear that it means *mailbox*. Consequently
4573 we must always qualify this address, regardless. */
4575 if (recipient_domain == 0)
4576 if (!(recipient_domain = qualify_recipient(&recipient, smtp_cmd_data,
4583 /* Check maximum allowed */
4585 if (rcpt_count > recipients_max && recipients_max > 0)
4587 if (recipients_max_reject)
4590 smtp_printf("552 too many recipients\r\n");
4592 log_write(0, LOG_MAIN|LOG_REJECT, "too many recipients: message "
4593 "rejected: sender=<%s> %s", sender_address, host_and_ident(TRUE));
4598 smtp_printf("452 too many recipients\r\n");
4600 log_write(0, LOG_MAIN|LOG_REJECT, "too many recipients: excess "
4601 "temporarily rejected: sender=<%s> %s", sender_address,
4602 host_and_ident(TRUE));
4609 /* If we have passed the threshold for rate limiting, apply the current
4610 delay, and update it for next time, provided this is a limited host. */
4612 if (rcpt_count > smtp_rlr_threshold &&
4613 verify_check_host(&smtp_ratelimit_hosts) == OK)
4615 DEBUG(D_receive) debug_printf("rate limit RCPT: delay %.3g sec\n",
4616 smtp_delay_rcpt/1000.0);
4617 millisleep((int)smtp_delay_rcpt);
4618 smtp_delay_rcpt *= smtp_rlr_factor;
4619 if (smtp_delay_rcpt > (double)smtp_rlr_limit)
4620 smtp_delay_rcpt = (double)smtp_rlr_limit;
4623 /* If the MAIL ACL discarded all the recipients, we bypass ACL checking
4624 for them. Otherwise, check the access control list for this recipient. As
4625 there may be a delay in this, re-check for a synchronization error
4626 afterwards, unless pipelining was advertised. */
4628 if (recipients_discarded) rc = DISCARD; else
4630 rc = acl_check(ACL_WHERE_RCPT, recipient, acl_smtp_rcpt, &user_msg,
4632 if (rc == OK && !pipelining_advertised && !check_sync())
4636 /* The ACL was happy */
4640 if (user_msg == NULL) smtp_printf("250 Accepted\r\n");
4641 else smtp_user_msg(US"250", user_msg);
4642 receive_add_recipient(recipient, -1);
4644 /* Set the dsn flags in the recipients_list */
4645 recipients_list[recipients_count-1].orcpt = orcpt;
4646 recipients_list[recipients_count-1].dsn_flags = flags;
4648 DEBUG(D_receive) debug_printf("DSN: orcpt: %s flags: %d\n",
4649 recipients_list[recipients_count-1].orcpt,
4650 recipients_list[recipients_count-1].dsn_flags);
4653 /* The recipient was discarded */
4655 else if (rc == DISCARD)
4657 if (user_msg == NULL) smtp_printf("250 Accepted\r\n");
4658 else smtp_user_msg(US"250", user_msg);
4661 log_write(0, LOG_MAIN|LOG_REJECT, "%s F=<%s> RCPT %s: "
4662 "discarded by %s ACL%s%s", host_and_ident(TRUE),
4663 sender_address_unrewritten? sender_address_unrewritten : sender_address,
4664 smtp_cmd_argument, recipients_discarded? "MAIL" : "RCPT",
4665 log_msg ? US": " : US"", log_msg ? log_msg : US"");
4668 /* Either the ACL failed the address, or it was deferred. */
4672 if (rc == FAIL) rcpt_fail_count++; else rcpt_defer_count++;
4673 done = smtp_handle_acl_fail(ACL_WHERE_RCPT, rc, user_msg, log_msg);
4678 /* The DATA command is legal only if it follows successful MAIL FROM
4679 and RCPT TO commands. However, if pipelining is advertised, a bad DATA is
4680 not counted as a protocol error if it follows RCPT (which must have been
4681 rejected if there are no recipients.) This function is complete when a
4682 valid DATA command is encountered.
4684 Note concerning the code used: RFC 2821 says this:
4686 - If there was no MAIL, or no RCPT, command, or all such commands
4687 were rejected, the server MAY return a "command out of sequence"
4688 (503) or "no valid recipients" (554) reply in response to the
4691 The example in the pipelining RFC 2920 uses 554, but I use 503 here
4692 because it is the same whether pipelining is in use or not.
4694 If all the RCPT commands that precede DATA provoked the same error message
4695 (often indicating some kind of system error), it is helpful to include it
4696 with the DATA rejection (an idea suggested by Tony Finch). */
4703 if (chunking_state != CHUNKING_OFFERED)
4705 done = synprot_error(L_smtp_protocol_error, 503, NULL,
4706 US"BDAT command used when CHUNKING not advertised");
4710 /* grab size, endmarker */
4712 if (sscanf(CS smtp_cmd_data, "%u %n", &chunking_datasize, &n) < 1)
4714 done = synprot_error(L_smtp_protocol_error, 501, NULL,
4715 US"missing size for BDAT command");
4718 chunking_state = strcmpic(smtp_cmd_data+n, US"LAST") == 0
4719 ? CHUNKING_LAST : CHUNKING_ACTIVE;
4720 chunking_data_left = chunking_datasize;
4722 lwr_receive_getc = receive_getc;
4723 lwr_receive_ungetc = receive_ungetc;
4724 receive_getc = bdat_getc;
4725 receive_ungetc = bdat_ungetc;
4728 debug_printf("chunking state %d\n", (int)chunking_state);
4735 DATA_BDAT: /* Common code for DATA and BDAT */
4736 if (!discarded && recipients_count <= 0)
4738 if (rcpt_smtp_response_same && rcpt_smtp_response != NULL)
4740 uschar *code = US"503";
4741 int len = Ustrlen(rcpt_smtp_response);
4742 smtp_respond(code, 3, FALSE, US"All RCPT commands were rejected with "
4744 /* Responses from smtp_printf() will have \r\n on the end */
4745 if (len > 2 && rcpt_smtp_response[len-2] == '\r')
4746 rcpt_smtp_response[len-2] = 0;
4747 smtp_respond(code, 3, FALSE, rcpt_smtp_response);
4749 if (pipelining_advertised && last_was_rcpt)
4750 smtp_printf("503 Valid RCPT command must precede %s\r\n",
4751 smtp_names[smtp_connection_had[smtp_ch_index-1]]);
4753 done = synprot_error(L_smtp_protocol_error, 503, NULL,
4754 smtp_connection_had[smtp_ch_index-1] == SCH_DATA
4755 ? US"valid RCPT command must precede DATA"
4756 : US"valid RCPT command must precede BDAT");
4760 if (toomany && recipients_max_reject)
4762 sender_address = NULL; /* This will allow a new MAIL without RSET */
4763 sender_address_unrewritten = NULL;
4764 smtp_printf("554 Too many recipients\r\n");
4768 if (chunking_state > CHUNKING_OFFERED)
4769 { /* No predata ACL or go-ahead output for BDAT */
4774 /* If there is an ACL, re-check the synchronization afterwards, since the
4775 ACL may have delayed. To handle cutthrough delivery enforce a dummy call
4776 to get the DATA command sent. */
4778 if (acl_smtp_predata == NULL && cutthrough.fd < 0)
4782 uschar * acl = acl_smtp_predata ? acl_smtp_predata : US"accept";
4783 enable_dollar_recipients = TRUE;
4784 rc = acl_check(ACL_WHERE_PREDATA, NULL, acl, &user_msg,
4786 enable_dollar_recipients = FALSE;
4787 if (rc == OK && !check_sync())
4791 { /* Either the ACL failed the address, or it was deferred. */
4792 done = smtp_handle_acl_fail(ACL_WHERE_PREDATA, rc, user_msg, log_msg);
4798 smtp_user_msg(US"354", user_msg);
4801 "354 Enter message, ending with \".\" on a line by itself\r\n");
4805 message_ended = END_NOTENDED; /* Indicate in middle of data */
4816 if (!(address = parse_extract_address(smtp_cmd_data, &errmess,
4817 &start, &end, &recipient_domain, FALSE)))
4819 smtp_printf("501 %s\r\n", errmess);
4823 if (recipient_domain == 0)
4824 if (!(recipient_domain = qualify_recipient(&address, smtp_cmd_data,
4828 if ((rc = acl_check(ACL_WHERE_VRFY, address, acl_smtp_vrfy,
4829 &user_msg, &log_msg)) != OK)
4830 done = smtp_handle_acl_fail(ACL_WHERE_VRFY, rc, user_msg, log_msg);
4834 address_item * addr = deliver_make_addr(address, FALSE);
4836 switch(verify_address(addr, NULL, vopt_is_recipient | vopt_qualify, -1,
4837 -1, -1, NULL, NULL, NULL))
4840 s = string_sprintf("250 <%s> is deliverable", address);
4844 s = (addr->user_message != NULL)?
4845 string_sprintf("451 <%s> %s", address, addr->user_message) :
4846 string_sprintf("451 Cannot resolve <%s> at this time", address);
4850 s = (addr->user_message != NULL)?
4851 string_sprintf("550 <%s> %s", address, addr->user_message) :
4852 string_sprintf("550 <%s> is not deliverable", address);
4853 log_write(0, LOG_MAIN, "VRFY failed for %s %s",
4854 smtp_cmd_argument, host_and_ident(TRUE));
4858 smtp_printf("%s\r\n", s);
4866 rc = acl_check(ACL_WHERE_EXPN, NULL, acl_smtp_expn, &user_msg, &log_msg);
4868 done = smtp_handle_acl_fail(ACL_WHERE_EXPN, rc, user_msg, log_msg);
4871 BOOL save_log_testing_mode = log_testing_mode;
4872 address_test_mode = log_testing_mode = TRUE;
4873 (void) verify_address(deliver_make_addr(smtp_cmd_data, FALSE),
4874 smtp_out, vopt_is_recipient | vopt_qualify | vopt_expn, -1, -1, -1,
4876 address_test_mode = FALSE;
4877 log_testing_mode = save_log_testing_mode; /* true for -bh */
4886 if (!tls_advertised)
4888 done = synprot_error(L_smtp_protocol_error, 503, NULL,
4889 US"STARTTLS command used when not advertised");
4893 /* Apply an ACL check if one is defined */
4895 if ( acl_smtp_starttls
4896 && (rc = acl_check(ACL_WHERE_STARTTLS, NULL, acl_smtp_starttls,
4897 &user_msg, &log_msg)) != OK
4900 done = smtp_handle_acl_fail(ACL_WHERE_STARTTLS, rc, user_msg, log_msg);
4904 /* RFC 2487 is not clear on when this command may be sent, though it
4905 does state that all information previously obtained from the client
4906 must be discarded if a TLS session is started. It seems reasonble to
4907 do an implied RSET when STARTTLS is received. */
4909 incomplete_transaction_log(US"STARTTLS");
4910 smtp_reset(reset_point);
4912 cmd_list[CMD_LIST_STARTTLS].is_mail_cmd = FALSE;
4914 /* There's an attack where more data is read in past the STARTTLS command
4915 before TLS is negotiated, then assumed to be part of the secure session
4916 when used afterwards; we use segregated input buffers, so are not
4917 vulnerable, but we want to note when it happens and, for sheer paranoia,
4918 ensure that the buffer is "wiped".
4919 Pipelining sync checks will normally have protected us too, unless disabled
4920 by configuration. */
4922 if (receive_smtp_buffered())
4925 debug_printf("Non-empty input buffer after STARTTLS; naive attack?\n");
4926 if (tls_in.active < 0)
4927 smtp_inend = smtp_inptr = smtp_inbuffer;
4928 /* and if TLS is already active, tls_server_start() should fail */
4931 /* There is nothing we value in the input buffer and if TLS is succesfully
4932 negotiated, we won't use this buffer again; if TLS fails, we'll just read
4933 fresh content into it. The buffer contains arbitrary content from an
4934 untrusted remote source; eg: NOOP <shellcode>\r\nSTARTTLS\r\n
4935 It seems safest to just wipe away the content rather than leave it as a
4936 target to jump to. */
4938 memset(smtp_inbuffer, 0, in_buffer_size);
4940 /* Attempt to start up a TLS session, and if successful, discard all
4941 knowledge that was obtained previously. At least, that's what the RFC says,
4942 and that's what happens by default. However, in order to work round YAEB,
4943 there is an option to remember the esmtp state. Sigh.
4945 We must allow for an extra EHLO command and an extra AUTH command after
4946 STARTTLS that don't add to the nonmail command count. */
4948 if ((rc = tls_server_start(tls_require_ciphers)) == OK)
4950 if (!tls_remember_esmtp)
4951 helo_seen = esmtp = auth_advertised = pipelining_advertised = FALSE;
4952 cmd_list[CMD_LIST_EHLO].is_mail_cmd = TRUE;
4953 cmd_list[CMD_LIST_AUTH].is_mail_cmd = TRUE;
4954 cmd_list[CMD_LIST_TLS_AUTH].is_mail_cmd = TRUE;
4955 if (sender_helo_name != NULL)
4957 store_free(sender_helo_name);
4958 sender_helo_name = NULL;
4959 host_build_sender_fullhost(); /* Rebuild */
4960 set_process_info("handling incoming TLS connection from %s",
4961 host_and_ident(FALSE));
4964 (sender_host_address ? protocols : protocols_local)
4966 ? pextend + (sender_host_authenticated ? pauthed : 0)
4968 + (tls_in.active >= 0 ? pcrpted : 0)
4971 sender_host_authenticated = NULL;
4972 authenticated_id = NULL;
4973 sync_cmd_limit = NON_SYNC_CMD_NON_PIPELINING;
4974 DEBUG(D_tls) debug_printf("TLS active\n");
4975 break; /* Successful STARTTLS */
4978 /* Some local configuration problem was discovered before actually trying
4979 to do a TLS handshake; give a temporary error. */
4981 else if (rc == DEFER)
4983 smtp_printf("454 TLS currently unavailable\r\n");
4987 /* Hard failure. Reject everything except QUIT or closed connection. One
4988 cause for failure is a nested STARTTLS, in which case tls_in.active remains
4989 set, but we must still reject all incoming commands. */
4991 DEBUG(D_tls) debug_printf("TLS failed to start\n");
4994 switch(smtp_read_command(FALSE))
4997 log_write(L_smtp_connection, LOG_MAIN, "%s closed by EOF",
4998 smtp_get_connection_info());
4999 smtp_notquit_exit(US"tls-failed", NULL, NULL);
5003 /* It is perhaps arguable as to which exit ACL should be called here,
5004 but as it is probably a situation that almost never arises, it
5005 probably doesn't matter. We choose to call the real QUIT ACL, which in
5006 some sense is perhaps "right". */
5010 if (acl_smtp_quit != NULL)
5012 rc = acl_check(ACL_WHERE_QUIT, NULL, acl_smtp_quit, &user_msg,
5015 log_write(0, LOG_MAIN|LOG_PANIC, "ACL for QUIT returned ERROR: %s",
5018 if (user_msg == NULL)
5019 smtp_printf("221 %s closing connection\r\n", smtp_active_hostname);
5021 smtp_respond(US"221", 3, TRUE, user_msg);
5022 log_write(L_smtp_connection, LOG_MAIN, "%s closed by QUIT",
5023 smtp_get_connection_info());
5028 smtp_printf("554 Security failure\r\n");
5032 tls_close(TRUE, TRUE);
5037 /* The ACL for QUIT is provided for gathering statistical information or
5038 similar; it does not affect the response code, but it can supply a custom
5042 smtp_quit_handler(&user_msg, &log_msg);
5048 smtp_rset_handler();
5049 smtp_reset(reset_point);
5056 smtp_printf("250 OK\r\n");
5060 /* Show ETRN/EXPN/VRFY if there's an ACL for checking hosts; if actually
5061 used, a check will be done for permitted hosts. Show STARTTLS only if not
5062 already in a TLS session and if it would be advertised in the EHLO
5067 smtp_printf("214-Commands supported:\r\n");
5071 Ustrcat(buffer, " AUTH");
5073 if (tls_in.active < 0 &&
5074 verify_check_host(&tls_advertise_hosts) != FAIL)
5075 Ustrcat(buffer, " STARTTLS");
5077 Ustrcat(buffer, " HELO EHLO MAIL RCPT DATA BDAT");
5078 Ustrcat(buffer, " NOOP QUIT RSET HELP");
5079 if (acl_smtp_etrn != NULL) Ustrcat(buffer, " ETRN");
5080 if (acl_smtp_expn != NULL) Ustrcat(buffer, " EXPN");
5081 if (acl_smtp_vrfy != NULL) Ustrcat(buffer, " VRFY");
5082 smtp_printf("214%s\r\n", buffer);
5088 incomplete_transaction_log(US"connection lost");
5089 smtp_notquit_exit(US"connection-lost", US"421",
5090 US"%s lost input connection", smtp_active_hostname);
5092 /* Don't log by default unless in the middle of a message, as some mailers
5093 just drop the call rather than sending QUIT, and it clutters up the logs.
5096 if (sender_address != NULL || recipients_count > 0)
5097 log_write(L_lost_incoming_connection,
5099 "unexpected %s while reading SMTP command from %s%s",
5100 sender_host_unknown? "EOF" : "disconnection",
5101 host_and_ident(FALSE), smtp_read_error);
5103 else log_write(L_smtp_connection, LOG_MAIN, "%s lost%s",
5104 smtp_get_connection_info(), smtp_read_error);
5112 if (sender_address != NULL)
5114 done = synprot_error(L_smtp_protocol_error, 503, NULL,
5115 US"ETRN is not permitted inside a transaction");
5119 log_write(L_etrn, LOG_MAIN, "ETRN %s received from %s", smtp_cmd_argument,
5120 host_and_ident(FALSE));
5122 if ((rc = acl_check(ACL_WHERE_ETRN, NULL, acl_smtp_etrn,
5123 &user_msg, &log_msg)) != OK)
5125 done = smtp_handle_acl_fail(ACL_WHERE_ETRN, rc, user_msg, log_msg);
5129 /* Compute the serialization key for this command. */
5131 etrn_serialize_key = string_sprintf("etrn-%s\n", smtp_cmd_data);
5133 /* If a command has been specified for running as a result of ETRN, we
5134 permit any argument to ETRN. If not, only the # standard form is permitted,
5135 since that is strictly the only kind of ETRN that can be implemented
5136 according to the RFC. */
5138 if (smtp_etrn_command != NULL)
5142 etrn_command = smtp_etrn_command;
5143 deliver_domain = smtp_cmd_data;
5144 rc = transport_set_up_command(&argv, smtp_etrn_command, TRUE, 0, NULL,
5145 US"ETRN processing", &error);
5146 deliver_domain = NULL;
5149 log_write(0, LOG_MAIN|LOG_PANIC, "failed to set up ETRN command: %s",
5151 smtp_printf("458 Internal failure\r\n");
5156 /* Else set up to call Exim with the -R option. */
5160 if (*smtp_cmd_data++ != '#')
5162 done = synprot_error(L_smtp_syntax_error, 501, NULL,
5163 US"argument must begin with #");
5166 etrn_command = US"exim -R";
5167 argv = CUSS child_exec_exim(CEE_RETURN_ARGV, TRUE, NULL, TRUE,
5168 *queue_name ? 4 : 2,
5169 US"-R", smtp_cmd_data,
5170 US"-MCG", queue_name);
5173 /* If we are host-testing, don't actually do anything. */
5179 debug_printf("ETRN command is: %s\n", etrn_command);
5180 debug_printf("ETRN command execution skipped\n");
5182 if (user_msg == NULL) smtp_printf("250 OK\r\n");
5183 else smtp_user_msg(US"250", user_msg);
5188 /* If ETRN queue runs are to be serialized, check the database to
5189 ensure one isn't already running. */
5191 if (smtp_etrn_serialize && !enq_start(etrn_serialize_key, 1))
5193 smtp_printf("458 Already processing %s\r\n", smtp_cmd_data);
5197 /* Fork a child process and run the command. We don't want to have to
5198 wait for the process at any point, so set SIGCHLD to SIG_IGN before
5199 forking. It should be set that way anyway for external incoming SMTP,
5200 but we save and restore to be tidy. If serialization is required, we
5201 actually run the command in yet another process, so we can wait for it
5202 to complete and then remove the serialization lock. */
5204 oldsignal = signal(SIGCHLD, SIG_IGN);
5206 if ((pid = fork()) == 0)
5208 smtp_input = FALSE; /* This process is not associated with the */
5209 (void)fclose(smtp_in); /* SMTP call any more. */
5210 (void)fclose(smtp_out);
5212 signal(SIGCHLD, SIG_DFL); /* Want to catch child */
5214 /* If not serializing, do the exec right away. Otherwise, fork down
5215 into another process. */
5217 if (!smtp_etrn_serialize || (pid = fork()) == 0)
5219 DEBUG(D_exec) debug_print_argv(argv);
5220 exim_nullstd(); /* Ensure std{in,out,err} exist */
5221 execv(CS argv[0], (char *const *)argv);
5222 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "exec of \"%s\" (ETRN) failed: %s",
5223 etrn_command, strerror(errno));
5224 _exit(EXIT_FAILURE); /* paranoia */
5227 /* Obey this if smtp_serialize and the 2nd fork yielded non-zero. That
5228 is, we are in the first subprocess, after forking again. All we can do
5229 for a failing fork is to log it. Otherwise, wait for the 2nd process to
5230 complete, before removing the serialization. */
5233 log_write(0, LOG_MAIN|LOG_PANIC, "2nd fork for serialized ETRN "
5234 "failed: %s", strerror(errno));
5238 DEBUG(D_any) debug_printf("waiting for serialized ETRN process %d\n",
5240 (void)wait(&status);
5241 DEBUG(D_any) debug_printf("serialized ETRN process %d ended\n",
5245 enq_end(etrn_serialize_key);
5246 _exit(EXIT_SUCCESS);
5249 /* Back in the top level SMTP process. Check that we started a subprocess
5250 and restore the signal state. */
5254 log_write(0, LOG_MAIN|LOG_PANIC, "fork of process for ETRN failed: %s",
5256 smtp_printf("458 Unable to fork process\r\n");
5257 if (smtp_etrn_serialize) enq_end(etrn_serialize_key);
5261 if (user_msg == NULL) smtp_printf("250 OK\r\n");
5262 else smtp_user_msg(US"250", user_msg);
5265 signal(SIGCHLD, oldsignal);
5270 done = synprot_error(L_smtp_syntax_error, 501, NULL,
5271 US"unexpected argument data");
5275 /* This currently happens only for NULLs, but could be extended. */
5278 done = synprot_error(L_smtp_syntax_error, 0, NULL, /* Just logs */
5279 US"NULL character(s) present (shown as '?')");
5280 smtp_printf("501 NULL characters are not allowed in SMTP commands\r\n");
5286 if (smtp_inend >= smtp_inbuffer + in_buffer_size)
5287 smtp_inend = smtp_inbuffer + in_buffer_size - 1;
5288 c = smtp_inend - smtp_inptr;
5289 if (c > 150) c = 150;
5291 incomplete_transaction_log(US"sync failure");
5292 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP protocol synchronization error "
5293 "(next input sent too soon: pipelining was%s advertised): "
5294 "rejected \"%s\" %s next input=\"%s\"",
5295 pipelining_advertised? "" : " not",
5296 smtp_cmd_buffer, host_and_ident(TRUE),
5297 string_printing(smtp_inptr));
5298 smtp_notquit_exit(US"synchronization-error", US"554",
5299 US"SMTP synchronization error");
5300 done = 1; /* Pretend eof - drops connection */
5304 case TOO_MANY_NONMAIL_CMD:
5305 s = smtp_cmd_buffer;
5306 while (*s != 0 && !isspace(*s)) s++;
5307 incomplete_transaction_log(US"too many non-mail commands");
5308 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
5309 "nonmail commands (last was \"%.*s\")", host_and_ident(FALSE),
5310 (int)(s - smtp_cmd_buffer), smtp_cmd_buffer);
5311 smtp_notquit_exit(US"bad-commands", US"554", US"Too many nonmail commands");
5312 done = 1; /* Pretend eof - drops connection */
5315 #ifdef SUPPORT_PROXY
5316 case PROXY_FAIL_IGNORE_CMD:
5317 smtp_printf("503 Command refused, required Proxy negotiation failed\r\n");
5322 if (unknown_command_count++ >= smtp_max_unknown_commands)
5324 log_write(L_smtp_syntax_error, LOG_MAIN,
5325 "SMTP syntax error in \"%s\" %s %s",
5326 string_printing(smtp_cmd_buffer), host_and_ident(TRUE),
5327 US"unrecognized command");
5328 incomplete_transaction_log(US"unrecognized command");
5329 smtp_notquit_exit(US"bad-commands", US"500",
5330 US"Too many unrecognized commands");
5332 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
5333 "unrecognized commands (last was \"%s\")", host_and_ident(FALSE),
5334 string_printing(smtp_cmd_buffer));
5337 done = synprot_error(L_smtp_syntax_error, 500, NULL,
5338 US"unrecognized command");
5342 /* This label is used by goto's inside loops that want to break out to
5343 the end of the command-processing loop. */
5346 last_was_rej_mail = was_rej_mail; /* Remember some last commands for */
5347 last_was_rcpt = was_rcpt; /* protocol error handling */
5351 return done - 2; /* Convert yield values */
5356 /* End of smtp_in.c */