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 */
77 /* This is a dummy to identify the non-sync commands when pipelining */
79 NON_SYNC_CMD_PIPELINING,
81 /* These commands need not be synchronized when pipelining */
83 MAIL_CMD, RCPT_CMD, RSET_CMD,
85 /* RFC3030 section 2: "After all MAIL and RCPT responses are collected and
86 processed the message is sent using a series of BDAT commands"
87 implies that BDAT should be synchronized. However, we see Google, at least,
88 sending MAIL,RCPT,BDAT-LAST in a single packet, clearly not waiting for
89 processing of the RPCT response(s). We shall do the same, and not require
94 /* This is a dummy to identify the non-sync commands when not pipelining */
96 NON_SYNC_CMD_NON_PIPELINING,
98 /* I have been unable to find a statement about the use of pipelining
99 with AUTH, so to be on the safe side it is here, though I kind of feel
100 it should be up there with the synchronized commands. */
104 /* I'm not sure about these, but I don't think they matter. */
109 PROXY_FAIL_IGNORE_CMD,
112 /* These are specials that don't correspond to actual commands */
114 EOF_CMD, OTHER_CMD, BADARG_CMD, BADCHAR_CMD, BADSYN_CMD,
115 TOO_MANY_NONMAIL_CMD };
118 /* This is a convenience macro for adding the identity of an SMTP command
119 to the circular buffer that holds a list of the last n received. */
122 smtp_connection_had[smtp_ch_index++] = n; \
123 if (smtp_ch_index >= SMTP_HBUFF_SIZE) smtp_ch_index = 0
126 /*************************************************
127 * Local static variables *
128 *************************************************/
130 static auth_instance *authenticated_by;
131 static BOOL auth_advertised;
133 static BOOL tls_advertised;
135 static BOOL dsn_advertised;
137 static BOOL helo_required = FALSE;
138 static BOOL helo_verify = FALSE;
139 static BOOL helo_seen;
140 static BOOL helo_accept_junk;
141 static BOOL count_nonmail;
142 static BOOL pipelining_advertised;
143 static BOOL rcpt_smtp_response_same;
144 static BOOL rcpt_in_progress;
145 static int nonmail_command_count;
146 static BOOL smtp_exit_function_called = 0;
148 static BOOL smtputf8_advertised;
150 static int synprot_error_count;
151 static int unknown_command_count;
152 static int sync_cmd_limit;
153 static int smtp_write_error = 0;
155 static uschar *rcpt_smtp_response;
156 static uschar *smtp_data_buffer;
157 static uschar *smtp_cmd_data;
159 /* We need to know the position of RSET, HELO, EHLO, AUTH, and STARTTLS. Their
160 final fields of all except AUTH are forced TRUE at the start of a new message
161 setup, to allow one of each between messages that is not counted as a nonmail
162 command. (In fact, only one of HELO/EHLO is not counted.) Also, we have to
163 allow a new EHLO after starting up TLS.
165 AUTH is "falsely" labelled as a mail command initially, so that it doesn't get
166 counted. However, the flag is changed when AUTH is received, so that multiple
167 failing AUTHs will eventually hit the limit. After a successful AUTH, another
168 AUTH is already forbidden. After a TLS session is started, AUTH's flag is again
169 forced TRUE, to allow for the re-authentication that can happen at that point.
171 QUIT is also "falsely" labelled as a mail command so that it doesn't up the
172 count of non-mail commands and possibly provoke an error.
174 tls_auth is a pseudo-command, never expected in input. It is activated
175 on TLS startup and looks for a tls authenticator. */
177 static smtp_cmd_list cmd_list[] = {
178 /* name len cmd has_arg is_mail_cmd */
180 { "rset", sizeof("rset")-1, RSET_CMD, FALSE, FALSE }, /* First */
181 { "helo", sizeof("helo")-1, HELO_CMD, TRUE, FALSE },
182 { "ehlo", sizeof("ehlo")-1, EHLO_CMD, TRUE, FALSE },
183 { "auth", sizeof("auth")-1, AUTH_CMD, TRUE, TRUE },
185 { "starttls", sizeof("starttls")-1, STARTTLS_CMD, FALSE, FALSE },
186 { "tls_auth", 0, TLS_AUTH_CMD, FALSE, TRUE },
189 /* If you change anything above here, also fix the definitions below. */
191 { "mail from:", sizeof("mail from:")-1, MAIL_CMD, TRUE, TRUE },
192 { "rcpt to:", sizeof("rcpt to:")-1, RCPT_CMD, TRUE, TRUE },
193 { "data", sizeof("data")-1, DATA_CMD, FALSE, TRUE },
194 { "bdat", sizeof("bdat")-1, BDAT_CMD, TRUE, TRUE },
195 { "quit", sizeof("quit")-1, QUIT_CMD, FALSE, TRUE },
196 { "noop", sizeof("noop")-1, NOOP_CMD, TRUE, FALSE },
197 { "etrn", sizeof("etrn")-1, ETRN_CMD, TRUE, FALSE },
198 { "vrfy", sizeof("vrfy")-1, VRFY_CMD, TRUE, FALSE },
199 { "expn", sizeof("expn")-1, EXPN_CMD, TRUE, FALSE },
200 { "help", sizeof("help")-1, HELP_CMD, TRUE, FALSE }
203 static smtp_cmd_list *cmd_list_end =
204 cmd_list + sizeof(cmd_list)/sizeof(smtp_cmd_list);
206 #define CMD_LIST_RSET 0
207 #define CMD_LIST_HELO 1
208 #define CMD_LIST_EHLO 2
209 #define CMD_LIST_AUTH 3
210 #define CMD_LIST_STARTTLS 4
211 #define CMD_LIST_TLS_AUTH 5
213 /* This list of names is used for performing the smtp_no_mail logging action.
214 It must be kept in step with the SCH_xxx enumerations. */
216 static uschar *smtp_names[] =
218 US"NONE", US"AUTH", US"DATA", US"BDAT", US"EHLO", US"ETRN", US"EXPN",
219 US"HELO", US"HELP", US"MAIL", US"NOOP", US"QUIT", US"RCPT", US"RSET",
220 US"STARTTLS", US"VRFY" };
222 static uschar *protocols_local[] = {
223 US"local-smtp", /* HELO */
224 US"local-smtps", /* The rare case EHLO->STARTTLS->HELO */
225 US"local-esmtp", /* EHLO */
226 US"local-esmtps", /* EHLO->STARTTLS->EHLO */
227 US"local-esmtpa", /* EHLO->AUTH */
228 US"local-esmtpsa" /* EHLO->STARTTLS->EHLO->AUTH */
230 static uschar *protocols[] = {
232 US"smtps", /* The rare case EHLO->STARTTLS->HELO */
233 US"esmtp", /* EHLO */
234 US"esmtps", /* EHLO->STARTTLS->EHLO */
235 US"esmtpa", /* EHLO->AUTH */
236 US"esmtpsa" /* EHLO->STARTTLS->EHLO->AUTH */
241 #define pcrpted 1 /* added to pextend or pnormal */
242 #define pauthed 2 /* added to pextend */
244 /* Sanity check and validate optional args to MAIL FROM: envelope */
247 ENV_MAIL_OPT_SIZE, ENV_MAIL_OPT_BODY, ENV_MAIL_OPT_AUTH,
251 ENV_MAIL_OPT_RET, ENV_MAIL_OPT_ENVID,
257 uschar * name; /* option requested during MAIL cmd */
258 int value; /* enum type */
259 BOOL need_value; /* TRUE requires value (name=value pair format)
260 FALSE is a singleton */
262 static env_mail_type_t env_mail_type_list[] = {
263 { US"SIZE", ENV_MAIL_OPT_SIZE, TRUE },
264 { US"BODY", ENV_MAIL_OPT_BODY, TRUE },
265 { US"AUTH", ENV_MAIL_OPT_AUTH, TRUE },
267 { US"PRDR", ENV_MAIL_OPT_PRDR, FALSE },
269 { US"RET", ENV_MAIL_OPT_RET, TRUE },
270 { US"ENVID", ENV_MAIL_OPT_ENVID, TRUE },
272 { US"SMTPUTF8",ENV_MAIL_OPT_UTF8, FALSE }, /* rfc6531 */
274 /* keep this the last entry */
275 { US"NULL", ENV_MAIL_OPT_NULL, FALSE },
278 /* When reading SMTP from a remote host, we have to use our own versions of the
279 C input-reading functions, in order to be able to flush the SMTP output only
280 when about to read more data from the socket. This is the only way to get
281 optimal performance when the client is using pipelining. Flushing for every
282 command causes a separate packet and reply packet each time; saving all the
283 responses up (when pipelining) combines them into one packet and one response.
285 For simplicity, these functions are used for *all* SMTP input, not only when
286 receiving over a socket. However, after setting up a secure socket (SSL), input
287 is read via the OpenSSL library, and another set of functions is used instead
290 These functions are set in the receive_getc etc. variables and called with the
291 same interface as the C functions. However, since there can only ever be
292 one incoming SMTP call, we just use a single buffer and flags. There is no need
293 to implement a complicated private FILE-like structure.*/
295 static uschar *smtp_inbuffer;
296 static uschar *smtp_inptr;
297 static uschar *smtp_inend;
298 static int smtp_had_eof;
299 static int smtp_had_error;
302 /* forward declarations */
303 int bdat_ungetc(int ch);
304 static int smtp_read_command(BOOL check_sync);
305 static int synprot_error(int type, int code, uschar *data, uschar *errmess);
306 static void smtp_quit_handler(uschar **, uschar **);
307 static void smtp_rset_handler(void);
309 /*************************************************
310 * SMTP version of getc() *
311 *************************************************/
313 /* This gets the next byte from the SMTP input buffer. If the buffer is empty,
314 it flushes the output, and refills the buffer, with a timeout. The signal
315 handler is set appropriately by the calling function. This function is not used
316 after a connection has negotated itself into an TLS/SSL state.
319 Returns: the next character or EOF
325 if (smtp_inptr >= smtp_inend)
328 if (!smtp_out) return EOF;
330 if (smtp_receive_timeout > 0) alarm(smtp_receive_timeout);
331 rc = read(fileno(smtp_in), smtp_inbuffer, in_buffer_size);
336 /* Must put the error text in fixed store, because this might be during
337 header reading, where it releases unused store above the header. */
340 smtp_had_error = save_errno;
341 smtp_read_error = string_copy_malloc(
342 string_sprintf(" (error: %s)", strerror(save_errno)));
344 else smtp_had_eof = 1;
348 dkim_exim_verify_feed(smtp_inbuffer, rc);
350 smtp_inend = smtp_inbuffer + rc;
351 smtp_inptr = smtp_inbuffer;
353 return *smtp_inptr++;
360 int n = smtp_inend - smtp_inptr;
362 dkim_exim_verify_feed(smtp_inptr, n);
367 /* Get a byte from the smtp input, in CHUNKING mode. Handle ack of the
368 previous BDAT chunk and getting new ones when we run out. Uses the
369 underlying smtp_getc or tls_getc both for that and for getting the
370 (buffered) data byte. EOD signals (an expected) no further data.
371 ERR signals a protocol error, and EOF a closed input stream.
373 Called from read_bdat_smtp() in receive.c for the message body, but also
374 by the headers read loop in receive_msg(); manipulates chunking_state
375 to handle the BDAT command/response.
376 Placed here due to the correlation with the above smtp_getc(), which it wraps,
377 and also by the need to do smtp command/response handling.
380 Returns: the next character or ERR, EOD or EOF
386 uschar * user_msg = NULL;
391 if (chunking_data_left-- > 0)
392 return lwr_receive_getc();
394 receive_getc = lwr_receive_getc;
395 receive_ungetc = lwr_receive_ungetc;
397 /* If not the last, ack the received chunk. The last response is delayed
398 until after the data ACL decides on it */
400 if (chunking_state == CHUNKING_LAST)
403 dkim_exim_verify_feed(NULL, 0); /* notify EOD */
408 chunking_state = CHUNKING_OFFERED;
409 smtp_printf("250 %u byte chunk received\r\n", chunking_datasize);
411 /* Expect another BDAT cmd from input. RFC 3030 says nothing about
412 QUIT, RSET or NOOP but handling them seems obvious */
415 switch(smtp_read_command(TRUE))
418 (void) synprot_error(L_smtp_protocol_error, 503, NULL,
419 US"only BDAT permissible after non-LAST BDAT");
422 switch(smtp_read_command(TRUE))
424 case QUIT_CMD: smtp_quit_handler(&user_msg, &log_msg); /*FALLTHROUGH */
425 case EOF_CMD: return EOF;
426 case RSET_CMD: smtp_rset_handler(); return ERR;
427 default: if (synprot_error(L_smtp_protocol_error, 503, NULL,
428 US"only RSET accepted now") > 0)
430 goto repeat_until_rset;
434 smtp_quit_handler(&user_msg, &log_msg);
445 smtp_printf("250 OK\r\n");
452 if (sscanf(CS smtp_cmd_data, "%u %n", &chunking_datasize, &n) < 1)
454 (void) synprot_error(L_smtp_protocol_error, 501, NULL,
455 US"missing size for BDAT command");
458 chunking_state = strcmpic(smtp_cmd_data+n, US"LAST") == 0
459 ? CHUNKING_LAST : CHUNKING_ACTIVE;
460 chunking_data_left = chunking_datasize;
462 if (chunking_datasize == 0)
463 if (chunking_state == CHUNKING_LAST)
467 (void) synprot_error(L_smtp_protocol_error, 504, NULL,
468 US"zero size for BDAT command");
469 goto repeat_until_rset;
472 receive_getc = bdat_getc;
473 receive_ungetc = bdat_ungetc;
474 break; /* to top of main loop */
481 bdat_flush_data(void)
483 while (chunking_data_left-- > 0)
484 if (lwr_receive_getc() < 0)
487 receive_getc = lwr_receive_getc;
488 receive_ungetc = lwr_receive_ungetc;
490 if (chunking_state != CHUNKING_LAST)
491 chunking_state = CHUNKING_OFFERED;
497 /*************************************************
498 * SMTP version of ungetc() *
499 *************************************************/
501 /* Puts a character back in the input buffer. Only ever
507 Returns: the character
521 chunking_data_left++;
522 return lwr_receive_ungetc(ch);
527 /*************************************************
528 * SMTP version of feof() *
529 *************************************************/
531 /* Tests for a previous EOF
534 Returns: non-zero if the eof flag is set
546 /*************************************************
547 * SMTP version of ferror() *
548 *************************************************/
550 /* Tests for a previous read error, and returns with errno
551 restored to what it was when the error was detected.
554 Returns: non-zero if the error flag is set
560 errno = smtp_had_error;
561 return smtp_had_error;
566 /*************************************************
567 * Test for characters in the SMTP buffer *
568 *************************************************/
570 /* Used at the end of a message
579 return smtp_inptr < smtp_inend;
584 /*************************************************
585 * Write formatted string to SMTP channel *
586 *************************************************/
588 /* This is a separate function so that we don't have to repeat everything for
589 TLS support or debugging. It is global so that the daemon and the
590 authentication functions can use it. It does not return any error indication,
591 because major problems such as dropped connections won't show up till an output
592 flush for non-TLS connections. The smtp_fflush() function is available for
593 checking that: for convenience, TLS output errors are remembered here so that
594 they are also picked up later by smtp_fflush().
598 ... optional arguments
604 smtp_printf(const char *format, ...)
608 va_start(ap, format);
609 smtp_vprintf(format, ap);
613 /* This is split off so that verify.c:respond_printf() can, in effect, call
614 smtp_printf(), bearing in mind that in C a vararg function can't directly
615 call another vararg function, only a function which accepts a va_list. */
618 smtp_vprintf(const char *format, va_list ap)
622 yield = string_vformat(big_buffer, big_buffer_size, format, ap);
626 void *reset_point = store_get(0);
627 uschar *msg_copy, *cr, *end;
628 msg_copy = string_copy(big_buffer);
629 end = msg_copy + Ustrlen(msg_copy);
630 while ((cr = Ustrchr(msg_copy, '\r')) != NULL) /* lose CRs */
631 memmove(cr, cr + 1, (end--) - cr);
632 debug_printf("SMTP>> %s", msg_copy);
633 store_reset(reset_point);
638 log_write(0, LOG_MAIN|LOG_PANIC, "string too large in smtp_printf()");
639 smtp_closedown(US"Unexpected error");
640 exim_exit(EXIT_FAILURE);
643 /* If this is the first output for a (non-batch) RCPT command, see if all RCPTs
644 have had the same. Note: this code is also present in smtp_respond(). It would
645 be tidier to have it only in one place, but when it was added, it was easier to
646 do it that way, so as not to have to mess with the code for the RCPT command,
647 which sometimes uses smtp_printf() and sometimes smtp_respond(). */
649 if (rcpt_in_progress)
651 if (rcpt_smtp_response == NULL)
652 rcpt_smtp_response = string_copy(big_buffer);
653 else if (rcpt_smtp_response_same &&
654 Ustrcmp(rcpt_smtp_response, big_buffer) != 0)
655 rcpt_smtp_response_same = FALSE;
656 rcpt_in_progress = FALSE;
659 /* Now write the string */
662 if (tls_in.active >= 0)
664 if (tls_write(TRUE, big_buffer, Ustrlen(big_buffer)) < 0)
665 smtp_write_error = -1;
670 if (fprintf(smtp_out, "%s", big_buffer) < 0) smtp_write_error = -1;
675 /*************************************************
676 * Flush SMTP out and check for error *
677 *************************************************/
679 /* This function isn't currently used within Exim (it detects errors when it
680 tries to read the next SMTP input), but is available for use in local_scan().
681 For non-TLS connections, it flushes the output and checks for errors. For
682 TLS-connections, it checks for a previously-detected TLS write error.
685 Returns: 0 for no error; -1 after an error
691 if (tls_in.active < 0 && fflush(smtp_out) != 0) smtp_write_error = -1;
692 return smtp_write_error;
697 /*************************************************
698 * SMTP command read timeout *
699 *************************************************/
701 /* Signal handler for timing out incoming SMTP commands. This attempts to
704 Argument: signal number (SIGALRM)
709 command_timeout_handler(int sig)
711 sig = sig; /* Keep picky compilers happy */
712 log_write(L_lost_incoming_connection,
713 LOG_MAIN, "SMTP command timeout on%s connection from %s",
714 (tls_in.active >= 0)? " TLS" : "",
715 host_and_ident(FALSE));
716 if (smtp_batched_input)
717 moan_smtp_batch(NULL, "421 SMTP command timeout"); /* Does not return */
718 smtp_notquit_exit(US"command-timeout", US"421",
719 US"%s: SMTP command timeout - closing connection", smtp_active_hostname);
720 exim_exit(EXIT_FAILURE);
725 /*************************************************
727 *************************************************/
729 /* Signal handler for handling SIGTERM. Again, try to finish tidily.
731 Argument: signal number (SIGTERM)
736 command_sigterm_handler(int sig)
738 sig = sig; /* Keep picky compilers happy */
739 log_write(0, LOG_MAIN, "%s closed after SIGTERM", smtp_get_connection_info());
740 if (smtp_batched_input)
741 moan_smtp_batch(NULL, "421 SIGTERM received"); /* Does not return */
742 smtp_notquit_exit(US"signal-exit", US"421",
743 US"%s: Service not available - closing connection", smtp_active_hostname);
744 exim_exit(EXIT_FAILURE);
751 /*************************************************
752 * Restore socket timeout to previous value *
753 *************************************************/
754 /* If the previous value was successfully retrieved, restore
755 it before returning control to the non-proxy routines
757 Arguments: fd - File descriptor for input
758 get_ok - Successfully retrieved previous values
759 tvtmp - Time struct with previous values
760 vslen - Length of time struct
764 restore_socket_timeout(int fd, int get_ok, struct timeval tvtmp, socklen_t vslen)
767 setsockopt(fd, SOL_SOCKET, SO_RCVTIMEO, (char *)&tvtmp, vslen);
770 /*************************************************
771 * Check if host is required proxy host *
772 *************************************************/
773 /* The function determines if inbound host will be a regular smtp host
774 or if it is configured that it must use Proxy Protocol.
781 check_proxy_protocol_host()
784 /* Cannot configure local connection as a proxy inbound */
785 if (sender_host_address == NULL) return proxy_session;
787 rc = verify_check_this_host(CUSS &hosts_proxy, NULL, NULL,
788 sender_host_address, NULL);
792 debug_printf("Detected proxy protocol configured host\n");
793 proxy_session = TRUE;
795 return proxy_session;
799 /*************************************************
800 * Setup host for proxy protocol *
801 *************************************************/
802 /* The function configures the connection based on a header from the
803 inbound host to use Proxy Protocol. The specification is very exact
804 so exit with an error if do not find the exact required pieces. This
805 includes an incorrect number of spaces separating args.
812 setup_proxy_protocol_host()
824 struct { /* TCP/UDP over IPv4, len = 12 */
830 struct { /* TCP/UDP over IPv6, len = 36 */
831 uint8_t src_addr[16];
832 uint8_t dst_addr[16];
836 struct { /* AF_UNIX sockets, len = 216 */
837 uschar src_addr[108];
838 uschar dst_addr[108];
844 /* Temp variables used in PPv2 address:port parsing */
846 char tmpip[INET_ADDRSTRLEN];
847 struct sockaddr_in tmpaddr;
848 char tmpip6[INET6_ADDRSTRLEN];
849 struct sockaddr_in6 tmpaddr6;
853 const char v2sig[12] = "\x0D\x0A\x0D\x0A\x00\x0D\x0A\x51\x55\x49\x54\x0A";
854 uschar *iptype; /* To display debug info */
857 struct timeval tvtmp;
859 vslen = sizeof(struct timeval);
861 fd = fileno(smtp_in);
863 /* Save current socket timeout values */
864 get_ok = getsockopt(fd, SOL_SOCKET, SO_RCVTIMEO, (char *)&tvtmp,
867 /* Proxy Protocol host must send header within a short time
868 (default 3 seconds) or it's considered invalid */
869 tv.tv_sec = PROXY_NEGOTIATION_TIMEOUT_SEC;
870 tv.tv_usec = PROXY_NEGOTIATION_TIMEOUT_USEC;
871 setsockopt(fd, SOL_SOCKET, SO_RCVTIMEO, (char *)&tv,
872 sizeof(struct timeval));
876 /* The inbound host was declared to be a Proxy Protocol host, so
877 don't do a PEEK into the data, actually slurp it up. */
878 ret = recv(fd, &hdr, sizeof(hdr), 0);
880 while (ret == -1 && errno == EINTR);
884 restore_socket_timeout(fd, get_ok, tvtmp, vslen);
885 return (errno == EAGAIN) ? 0 : ERRNO_PROXYFAIL;
889 memcmp(&hdr.v2, v2sig, 12) == 0)
893 /* May 2014: haproxy combined the version and command into one byte to
894 allow two full bytes for the length field in order to proxy SSL
895 connections. SSL Proxy is not supported in this version of Exim, but
896 must still seperate values here. */
897 ver = (hdr.v2.ver_cmd & 0xf0) >> 4;
898 cmd = (hdr.v2.ver_cmd & 0x0f);
902 DEBUG(D_receive) debug_printf("Invalid Proxy Protocol version: %d\n", ver);
905 DEBUG(D_receive) debug_printf("Detected PROXYv2 header\n");
906 /* The v2 header will always be 16 bytes per the spec. */
907 size = 16 + hdr.v2.len;
910 DEBUG(D_receive) debug_printf("Truncated or too large PROXYv2 header (%d/%d)\n",
916 case 0x01: /* PROXY command */
919 case 0x11: /* TCPv4 address type */
921 tmpaddr.sin_addr.s_addr = hdr.v2.addr.ip4.src_addr;
922 inet_ntop(AF_INET, &(tmpaddr.sin_addr), (char *)&tmpip, sizeof(tmpip));
923 if (!string_is_ip_address(US tmpip,NULL))
925 DEBUG(D_receive) debug_printf("Invalid %s source IP\n", iptype);
926 return ERRNO_PROXYFAIL;
928 proxy_local_address = sender_host_address;
929 sender_host_address = string_copy(US tmpip);
930 tmpport = ntohs(hdr.v2.addr.ip4.src_port);
931 proxy_local_port = sender_host_port;
932 sender_host_port = tmpport;
933 /* Save dest ip/port */
934 tmpaddr.sin_addr.s_addr = hdr.v2.addr.ip4.dst_addr;
935 inet_ntop(AF_INET, &(tmpaddr.sin_addr), (char *)&tmpip, sizeof(tmpip));
936 if (!string_is_ip_address(US tmpip,NULL))
938 DEBUG(D_receive) debug_printf("Invalid %s dest port\n", iptype);
939 return ERRNO_PROXYFAIL;
941 proxy_external_address = string_copy(US tmpip);
942 tmpport = ntohs(hdr.v2.addr.ip4.dst_port);
943 proxy_external_port = tmpport;
945 case 0x21: /* TCPv6 address type */
947 memmove(tmpaddr6.sin6_addr.s6_addr, hdr.v2.addr.ip6.src_addr, 16);
948 inet_ntop(AF_INET6, &(tmpaddr6.sin6_addr), (char *)&tmpip6, sizeof(tmpip6));
949 if (!string_is_ip_address(US tmpip6,NULL))
951 DEBUG(D_receive) debug_printf("Invalid %s source IP\n", iptype);
952 return ERRNO_PROXYFAIL;
954 proxy_local_address = sender_host_address;
955 sender_host_address = string_copy(US tmpip6);
956 tmpport = ntohs(hdr.v2.addr.ip6.src_port);
957 proxy_local_port = sender_host_port;
958 sender_host_port = tmpport;
959 /* Save dest ip/port */
960 memmove(tmpaddr6.sin6_addr.s6_addr, hdr.v2.addr.ip6.dst_addr, 16);
961 inet_ntop(AF_INET6, &(tmpaddr6.sin6_addr), (char *)&tmpip6, sizeof(tmpip6));
962 if (!string_is_ip_address(US tmpip6,NULL))
964 DEBUG(D_receive) debug_printf("Invalid %s dest port\n", iptype);
965 return ERRNO_PROXYFAIL;
967 proxy_external_address = string_copy(US tmpip6);
968 tmpport = ntohs(hdr.v2.addr.ip6.dst_port);
969 proxy_external_port = tmpport;
973 debug_printf("Unsupported PROXYv2 connection type: 0x%02x\n",
977 /* Unsupported protocol, keep local connection address */
979 case 0x00: /* LOCAL command */
980 /* Keep local connection address for LOCAL */
984 debug_printf("Unsupported PROXYv2 command: 0x%x\n", cmd);
989 memcmp(hdr.v1.line, "PROXY", 5) == 0)
991 uschar *p = string_copy(hdr.v1.line);
992 uschar *end = memchr(p, '\r', ret - 1);
993 uschar *sp; /* Utility variables follow */
997 if (!end || end[1] != '\n')
999 DEBUG(D_receive) debug_printf("Partial or invalid PROXY header\n");
1002 *end = '\0'; /* Terminate the string */
1003 size = end + 2 - hdr.v1.line; /* Skip header + CRLF */
1004 DEBUG(D_receive) debug_printf("Detected PROXYv1 header\n");
1005 /* Step through the string looking for the required fields. Ensure
1006 strict adherance to required formatting, exit for any error. */
1008 if (!isspace(*(p++)))
1010 DEBUG(D_receive) debug_printf("Missing space after PROXY command\n");
1013 if (!Ustrncmp(p, CCS"TCP4", 4))
1015 else if (!Ustrncmp(p,CCS"TCP6", 4))
1017 else if (!Ustrncmp(p,CCS"UNKNOWN", 7))
1019 iptype = US"Unknown";
1024 DEBUG(D_receive) debug_printf("Invalid TCP type\n");
1028 p += Ustrlen(iptype);
1029 if (!isspace(*(p++)))
1031 DEBUG(D_receive) debug_printf("Missing space after TCP4/6 command\n");
1034 /* Find the end of the arg */
1035 if ((sp = Ustrchr(p, ' ')) == NULL)
1038 debug_printf("Did not find proxied src %s\n", iptype);
1042 if(!string_is_ip_address(p,NULL))
1045 debug_printf("Proxied src arg is not an %s address\n", iptype);
1048 proxy_local_address = sender_host_address;
1049 sender_host_address = p;
1051 if ((sp = Ustrchr(p, ' ')) == NULL)
1054 debug_printf("Did not find proxy dest %s\n", iptype);
1058 if(!string_is_ip_address(p,NULL))
1061 debug_printf("Proxy dest arg is not an %s address\n", iptype);
1064 proxy_external_address = p;
1066 if ((sp = Ustrchr(p, ' ')) == NULL)
1068 DEBUG(D_receive) debug_printf("Did not find proxied src port\n");
1072 tmp_port = strtol(CCS p,&endc,10);
1073 if (*endc || tmp_port == 0)
1076 debug_printf("Proxied src port '%s' not an integer\n", p);
1079 proxy_local_port = sender_host_port;
1080 sender_host_port = tmp_port;
1082 if ((sp = Ustrchr(p, '\0')) == NULL)
1084 DEBUG(D_receive) debug_printf("Did not find proxy dest port\n");
1087 tmp_port = strtol(CCS p,&endc,10);
1088 if (*endc || tmp_port == 0)
1091 debug_printf("Proxy dest port '%s' not an integer\n", p);
1094 proxy_external_port = tmp_port;
1095 /* Already checked for /r /n above. Good V1 header received. */
1100 /* Wrong protocol */
1101 DEBUG(D_receive) debug_printf("Invalid proxy protocol version negotiation\n");
1106 restore_socket_timeout(fd, get_ok, tvtmp, vslen);
1107 /* Don't flush any potential buffer contents. Any input should cause a
1108 synchronization failure */
1112 restore_socket_timeout(fd, get_ok, tvtmp, vslen);
1114 debug_printf("Valid %s sender from Proxy Protocol header\n", iptype);
1115 return proxy_session;
1119 /*************************************************
1120 * Read one command line *
1121 *************************************************/
1123 /* Strictly, SMTP commands coming over the net are supposed to end with CRLF.
1124 There are sites that don't do this, and in any case internal SMTP probably
1125 should check only for LF. Consequently, we check here for LF only. The line
1126 ends up with [CR]LF removed from its end. If we get an overlong line, treat as
1127 an unknown command. The command is read into the global smtp_cmd_buffer so that
1128 it is available via $smtp_command.
1130 The character reading routine sets up a timeout for each block actually read
1131 from the input (which may contain more than one command). We set up a special
1132 signal handler that closes down the session on a timeout. Control does not
1133 return when it runs.
1136 check_sync if TRUE, check synchronization rules if global option is TRUE
1138 Returns: a code identifying the command (enumerated above)
1142 smtp_read_command(BOOL check_sync)
1147 BOOL hadnull = FALSE;
1149 os_non_restarting_signal(SIGALRM, command_timeout_handler);
1151 while ((c = (receive_getc)()) != '\n' && c != EOF)
1153 if (ptr >= smtp_cmd_buffer_size)
1155 os_non_restarting_signal(SIGALRM, sigalrm_handler);
1163 smtp_cmd_buffer[ptr++] = c;
1166 receive_linecount++; /* For BSMTP errors */
1167 os_non_restarting_signal(SIGALRM, sigalrm_handler);
1169 /* If hit end of file, return pseudo EOF command. Whether we have a
1170 part-line already read doesn't matter, since this is an error state. */
1172 if (c == EOF) return EOF_CMD;
1174 /* Remove any CR and white space at the end of the line, and terminate the
1177 while (ptr > 0 && isspace(smtp_cmd_buffer[ptr-1])) ptr--;
1178 smtp_cmd_buffer[ptr] = 0;
1180 DEBUG(D_receive) debug_printf("SMTP<< %s\n", smtp_cmd_buffer);
1182 /* NULLs are not allowed in SMTP commands */
1184 if (hadnull) return BADCHAR_CMD;
1186 /* Scan command list and return identity, having set the data pointer
1187 to the start of the actual data characters. Check for SMTP synchronization
1190 for (p = cmd_list; p < cmd_list_end; p++)
1192 #ifdef SUPPORT_PROXY
1193 /* Only allow QUIT command if Proxy Protocol parsing failed */
1194 if (proxy_session && proxy_session_failed)
1196 if (p->cmd != QUIT_CMD)
1201 && strncmpic(smtp_cmd_buffer, US p->name, p->len) == 0
1202 && ( smtp_cmd_buffer[p->len-1] == ':' /* "mail from:" or "rcpt to:" */
1203 || smtp_cmd_buffer[p->len] == 0
1204 || smtp_cmd_buffer[p->len] == ' '
1207 if (smtp_inptr < smtp_inend && /* Outstanding input */
1208 p->cmd < sync_cmd_limit && /* Command should sync */
1209 check_sync && /* Local flag set */
1210 smtp_enforce_sync && /* Global flag set */
1211 sender_host_address != NULL && /* Not local input */
1212 !sender_host_notsocket) /* Really is a socket */
1215 /* The variables $smtp_command and $smtp_command_argument point into the
1216 unmodified input buffer. A copy of the latter is taken for actual
1217 processing, so that it can be chopped up into separate parts if necessary,
1218 for example, when processing a MAIL command options such as SIZE that can
1219 follow the sender address. */
1221 smtp_cmd_argument = smtp_cmd_buffer + p->len;
1222 while (isspace(*smtp_cmd_argument)) smtp_cmd_argument++;
1223 Ustrcpy(smtp_data_buffer, smtp_cmd_argument);
1224 smtp_cmd_data = smtp_data_buffer;
1226 /* Count non-mail commands from those hosts that are controlled in this
1227 way. The default is all hosts. We don't waste effort checking the list
1228 until we get a non-mail command, but then cache the result to save checking
1229 again. If there's a DEFER while checking the host, assume it's in the list.
1231 Note that one instance of RSET, EHLO/HELO, and STARTTLS is allowed at the
1232 start of each incoming message by fiddling with the value in the table. */
1234 if (!p->is_mail_cmd)
1236 if (count_nonmail == TRUE_UNSET) count_nonmail =
1237 verify_check_host(&smtp_accept_max_nonmail_hosts) != FAIL;
1238 if (count_nonmail && ++nonmail_command_count > smtp_accept_max_nonmail)
1239 return TOO_MANY_NONMAIL_CMD;
1242 /* If there is data for a command that does not expect it, generate the
1245 return (p->has_arg || *smtp_cmd_data == 0)? p->cmd : BADARG_CMD;
1249 #ifdef SUPPORT_PROXY
1250 /* Only allow QUIT command if Proxy Protocol parsing failed */
1251 if (proxy_session && proxy_session_failed)
1252 return PROXY_FAIL_IGNORE_CMD;
1255 /* Enforce synchronization for unknown commands */
1257 if (smtp_inptr < smtp_inend && /* Outstanding input */
1258 check_sync && /* Local flag set */
1259 smtp_enforce_sync && /* Global flag set */
1260 sender_host_address != NULL && /* Not local input */
1261 !sender_host_notsocket) /* Really is a socket */
1269 /*************************************************
1270 * Recheck synchronization *
1271 *************************************************/
1273 /* Synchronization checks can never be perfect because a packet may be on its
1274 way but not arrived when the check is done. Such checks can in any case only be
1275 done when TLS is not in use. Normally, the checks happen when commands are
1276 read: Exim ensures that there is no more input in the input buffer. In normal
1277 cases, the response to the command will be fast, and there is no further check.
1279 However, for some commands an ACL is run, and that can include delays. In those
1280 cases, it is useful to do another check on the input just before sending the
1281 response. This also applies at the start of a connection. This function does
1282 that check by means of the select() function, as long as the facility is not
1283 disabled or inappropriate. A failure of select() is ignored.
1285 When there is unwanted input, we read it so that it appears in the log of the
1289 Returns: TRUE if all is well; FALSE if there is input pending
1297 struct timeval tzero;
1299 if (!smtp_enforce_sync || sender_host_address == NULL ||
1300 sender_host_notsocket || tls_in.active >= 0)
1303 fd = fileno(smtp_in);
1308 rc = select(fd + 1, (SELECT_ARG2_TYPE *)&fds, NULL, NULL, &tzero);
1310 if (rc <= 0) return TRUE; /* Not ready to read */
1312 if (rc < 0) return TRUE; /* End of file or error */
1315 rc = smtp_inend - smtp_inptr;
1316 if (rc > 150) rc = 150;
1323 /*************************************************
1324 * Forced closedown of call *
1325 *************************************************/
1327 /* This function is called from log.c when Exim is dying because of a serious
1328 disaster, and also from some other places. If an incoming non-batched SMTP
1329 channel is open, it swallows the rest of the incoming message if in the DATA
1330 phase, sends the reply string, and gives an error to all subsequent commands
1331 except QUIT. The existence of an SMTP call is detected by the non-NULLness of
1335 message SMTP reply string to send, excluding the code
1341 smtp_closedown(uschar *message)
1343 if (smtp_in == NULL || smtp_batched_input) return;
1344 receive_swallow_smtp();
1345 smtp_printf("421 %s\r\n", message);
1347 for (;;) switch(smtp_read_command(FALSE))
1353 smtp_printf("221 %s closing connection\r\n", smtp_active_hostname);
1358 smtp_printf("250 Reset OK\r\n");
1362 smtp_printf("421 %s\r\n", message);
1370 /*************************************************
1371 * Set up connection info for logging *
1372 *************************************************/
1374 /* This function is called when logging information about an SMTP connection.
1375 It sets up appropriate source information, depending on the type of connection.
1376 If sender_fullhost is NULL, we are at a very early stage of the connection;
1377 just use the IP address.
1380 Returns: a string describing the connection
1384 smtp_get_connection_info(void)
1386 uschar *hostname = (sender_fullhost == NULL)?
1387 sender_host_address : sender_fullhost;
1390 return string_sprintf("SMTP connection from %s", hostname);
1392 if (sender_host_unknown || sender_host_notsocket)
1393 return string_sprintf("SMTP connection from %s", sender_ident);
1396 return string_sprintf("SMTP connection from %s (via inetd)", hostname);
1398 if (LOGGING(incoming_interface) && interface_address != NULL)
1399 return string_sprintf("SMTP connection from %s I=[%s]:%d", hostname,
1400 interface_address, interface_port);
1402 return string_sprintf("SMTP connection from %s", hostname);
1408 /* Append TLS-related information to a log line
1411 s String under construction: allocated string to extend, or NULL
1412 sizep Pointer to current allocation size (update on return), or NULL
1413 ptrp Pointer to index for new entries in string (update on return), or NULL
1415 Returns: Allocated string or NULL
1418 s_tlslog(uschar * s, int * sizep, int * ptrp)
1420 int size = sizep ? *sizep : 0;
1421 int ptr = ptrp ? *ptrp : 0;
1423 if (LOGGING(tls_cipher) && tls_in.cipher != NULL)
1424 s = string_append(s, &size, &ptr, 2, US" X=", tls_in.cipher);
1425 if (LOGGING(tls_certificate_verified) && tls_in.cipher != NULL)
1426 s = string_append(s, &size, &ptr, 2, US" CV=",
1427 tls_in.certificate_verified? "yes":"no");
1428 if (LOGGING(tls_peerdn) && tls_in.peerdn != NULL)
1429 s = string_append(s, &size, &ptr, 3, US" DN=\"",
1430 string_printing(tls_in.peerdn), US"\"");
1431 if (LOGGING(tls_sni) && tls_in.sni != NULL)
1432 s = string_append(s, &size, &ptr, 3, US" SNI=\"",
1433 string_printing(tls_in.sni), US"\"");
1438 if (sizep) *sizep = size;
1439 if (ptrp) *ptrp = ptr;
1445 /*************************************************
1446 * Log lack of MAIL if so configured *
1447 *************************************************/
1449 /* This function is called when an SMTP session ends. If the log selector
1450 smtp_no_mail is set, write a log line giving some details of what has happened
1451 in the SMTP session.
1458 smtp_log_no_mail(void)
1463 if (smtp_mailcmd_count > 0 || !LOGGING(smtp_no_mail))
1469 if (sender_host_authenticated != NULL)
1471 s = string_append(s, &size, &ptr, 2, US" A=", sender_host_authenticated);
1472 if (authenticated_id != NULL)
1473 s = string_append(s, &size, &ptr, 2, US":", authenticated_id);
1477 s = s_tlslog(s, &size, &ptr);
1480 sep = (smtp_connection_had[SMTP_HBUFF_SIZE-1] != SCH_NONE)?
1481 US" C=..." : US" C=";
1482 for (i = smtp_ch_index; i < SMTP_HBUFF_SIZE; i++)
1484 if (smtp_connection_had[i] != SCH_NONE)
1486 s = string_append(s, &size, &ptr, 2, sep,
1487 smtp_names[smtp_connection_had[i]]);
1492 for (i = 0; i < smtp_ch_index; i++)
1494 s = string_append(s, &size, &ptr, 2, sep, smtp_names[smtp_connection_had[i]]);
1498 if (s != NULL) s[ptr] = 0; else s = US"";
1499 log_write(0, LOG_MAIN, "no MAIL in SMTP connection from %s D=%s%s",
1500 host_and_ident(FALSE),
1501 readconf_printtime( (int) ((long)time(NULL) - (long)smtp_connection_start)),
1507 /*************************************************
1508 * Check HELO line and set sender_helo_name *
1509 *************************************************/
1511 /* Check the format of a HELO line. The data for HELO/EHLO is supposed to be
1512 the domain name of the sending host, or an ip literal in square brackets. The
1513 arrgument is placed in sender_helo_name, which is in malloc store, because it
1514 must persist over multiple incoming messages. If helo_accept_junk is set, this
1515 host is permitted to send any old junk (needed for some broken hosts).
1516 Otherwise, helo_allow_chars can be used for rogue characters in general
1517 (typically people want to let in underscores).
1520 s the data portion of the line (already past any white space)
1522 Returns: TRUE or FALSE
1526 check_helo(uschar *s)
1529 uschar *end = s + Ustrlen(s);
1530 BOOL yield = helo_accept_junk;
1532 /* Discard any previous helo name */
1534 if (sender_helo_name != NULL)
1536 store_free(sender_helo_name);
1537 sender_helo_name = NULL;
1540 /* Skip tests if junk is permitted. */
1544 /* Allow the new standard form for IPv6 address literals, namely,
1545 [IPv6:....], and because someone is bound to use it, allow an equivalent
1546 IPv4 form. Allow plain addresses as well. */
1553 if (strncmpic(s, US"[IPv6:", 6) == 0)
1554 yield = (string_is_ip_address(s+6, NULL) == 6);
1555 else if (strncmpic(s, US"[IPv4:", 6) == 0)
1556 yield = (string_is_ip_address(s+6, NULL) == 4);
1558 yield = (string_is_ip_address(s+1, NULL) != 0);
1563 /* Non-literals must be alpha, dot, hyphen, plus any non-valid chars
1564 that have been configured (usually underscore - sigh). */
1571 if (!isalnum(*s) && *s != '.' && *s != '-' &&
1572 Ustrchr(helo_allow_chars, *s) == NULL)
1582 /* Save argument if OK */
1584 if (yield) sender_helo_name = string_copy_malloc(start);
1592 /*************************************************
1593 * Extract SMTP command option *
1594 *************************************************/
1596 /* This function picks the next option setting off the end of smtp_cmd_data. It
1597 is called for MAIL FROM and RCPT TO commands, to pick off the optional ESMTP
1598 things that can appear there.
1601 name point this at the name
1602 value point this at the data string
1604 Returns: TRUE if found an option
1608 extract_option(uschar **name, uschar **value)
1611 uschar *v = smtp_cmd_data + Ustrlen(smtp_cmd_data) - 1;
1612 while (isspace(*v)) v--;
1614 while (v > smtp_cmd_data && *v != '=' && !isspace(*v)) v--;
1619 while(isalpha(n[-1])) n--;
1620 /* RFC says SP, but TAB seen in wild and other major MTAs accept it */
1621 if (!isspace(n[-1])) return FALSE;
1627 if (v == smtp_cmd_data) return FALSE;
1639 /*************************************************
1640 * Reset for new message *
1641 *************************************************/
1643 /* This function is called whenever the SMTP session is reset from
1644 within either of the setup functions.
1646 Argument: the stacking pool storage reset point
1651 smtp_reset(void *reset_point)
1653 store_reset(reset_point);
1654 recipients_list = NULL;
1655 rcpt_count = rcpt_defer_count = rcpt_fail_count =
1656 raw_recipients_count = recipients_count = recipients_list_max = 0;
1657 cancel_cutthrough_connection("smtp reset");
1658 message_linecount = 0;
1660 acl_added_headers = NULL;
1661 acl_removed_headers = NULL;
1662 queue_only_policy = FALSE;
1663 rcpt_smtp_response = NULL;
1664 rcpt_smtp_response_same = TRUE;
1665 rcpt_in_progress = FALSE;
1666 deliver_freeze = FALSE; /* Can be set by ACL */
1667 freeze_tell = freeze_tell_config; /* Can be set by ACL */
1668 fake_response = OK; /* Can be set by ACL */
1669 #ifdef WITH_CONTENT_SCAN
1670 no_mbox_unspool = FALSE; /* Can be set by ACL */
1672 submission_mode = FALSE; /* Can be set by ACL */
1673 suppress_local_fixups = suppress_local_fixups_default; /* Can be set by ACL */
1674 active_local_from_check = local_from_check; /* Can be set by ACL */
1675 active_local_sender_retain = local_sender_retain; /* Can be set by ACL */
1676 sender_address = NULL;
1677 submission_name = NULL; /* Can be set by ACL */
1678 raw_sender = NULL; /* After SMTP rewrite, before qualifying */
1679 sender_address_unrewritten = NULL; /* Set only after verify rewrite */
1680 sender_verified_list = NULL; /* No senders verified */
1681 memset(sender_address_cache, 0, sizeof(sender_address_cache));
1682 memset(sender_domain_cache, 0, sizeof(sender_domain_cache));
1684 authenticated_sender = NULL;
1685 #ifdef EXPERIMENTAL_BRIGHTMAIL
1687 bmi_verdicts = NULL;
1689 #ifndef DISABLE_DKIM
1690 dkim_signers = NULL;
1691 dkim_disable_verify = FALSE;
1692 dkim_collect_input = FALSE;
1696 #ifndef DISABLE_PRDR
1697 prdr_requested = FALSE;
1699 #ifdef EXPERIMENTAL_SPF
1700 spf_header_comment = NULL;
1701 spf_received = NULL;
1703 spf_smtp_comment = NULL;
1706 message_smtputf8 = FALSE;
1708 body_linecount = body_zerocount = 0;
1710 sender_rate = sender_rate_limit = sender_rate_period = NULL;
1711 ratelimiters_mail = NULL; /* Updated by ratelimit ACL condition */
1712 /* Note that ratelimiters_conn persists across resets. */
1714 /* Reset message ACL variables */
1718 /* The message body variables use malloc store. They may be set if this is
1719 not the first message in an SMTP session and the previous message caused them
1720 to be referenced in an ACL. */
1722 if (message_body != NULL)
1724 store_free(message_body);
1725 message_body = NULL;
1728 if (message_body_end != NULL)
1730 store_free(message_body_end);
1731 message_body_end = NULL;
1734 /* Warning log messages are also saved in malloc store. They are saved to avoid
1735 repetition in the same message, but it seems right to repeat them for different
1738 while (acl_warn_logged != NULL)
1740 string_item *this = acl_warn_logged;
1741 acl_warn_logged = acl_warn_logged->next;
1750 /*************************************************
1751 * Initialize for incoming batched SMTP message *
1752 *************************************************/
1754 /* This function is called from smtp_setup_msg() in the case when
1755 smtp_batched_input is true. This happens when -bS is used to pass a whole batch
1756 of messages in one file with SMTP commands between them. All errors must be
1757 reported by sending a message, and only MAIL FROM, RCPT TO, and DATA are
1758 relevant. After an error on a sender, or an invalid recipient, the remainder
1759 of the message is skipped. The value of received_protocol is already set.
1762 Returns: > 0 message successfully started (reached DATA)
1763 = 0 QUIT read or end of file reached
1764 < 0 should not occur
1768 smtp_setup_batch_msg(void)
1771 void *reset_point = store_get(0);
1773 /* Save the line count at the start of each transaction - single commands
1774 like HELO and RSET count as whole transactions. */
1776 bsmtp_transaction_linecount = receive_linecount;
1778 if ((receive_feof)()) return 0; /* Treat EOF as QUIT */
1780 smtp_reset(reset_point); /* Reset for start of message */
1782 /* Deal with SMTP commands. This loop is exited by setting done to a POSITIVE
1783 value. The values are 2 larger than the required yield of the function. */
1788 uschar *recipient = NULL;
1789 int start, end, sender_domain, recipient_domain;
1791 switch(smtp_read_command(FALSE))
1793 /* The HELO/EHLO commands set sender_address_helo if they have
1794 valid data; otherwise they are ignored, except that they do
1795 a reset of the state. */
1800 check_helo(smtp_cmd_data);
1804 smtp_reset(reset_point);
1805 bsmtp_transaction_linecount = receive_linecount;
1809 /* The MAIL FROM command requires an address as an operand. All we
1810 do here is to parse it for syntactic correctness. The form "<>" is
1811 a special case which converts into an empty string. The start/end
1812 pointers in the original are not used further for this address, as
1813 it is the canonical extracted address which is all that is kept. */
1816 smtp_mailcmd_count++; /* Count for no-mail log */
1817 if (sender_address != NULL)
1818 /* The function moan_smtp_batch() does not return. */
1819 moan_smtp_batch(smtp_cmd_buffer, "503 Sender already given");
1821 if (smtp_cmd_data[0] == 0)
1822 /* The function moan_smtp_batch() does not return. */
1823 moan_smtp_batch(smtp_cmd_buffer, "501 MAIL FROM must have an address operand");
1825 /* Reset to start of message */
1827 smtp_reset(reset_point);
1829 /* Apply SMTP rewrite */
1831 raw_sender = ((rewrite_existflags & rewrite_smtp) != 0)?
1832 rewrite_one(smtp_cmd_data, rewrite_smtp|rewrite_smtp_sender, NULL, FALSE,
1833 US"", global_rewrite_rules) : smtp_cmd_data;
1835 /* Extract the address; the TRUE flag allows <> as valid */
1838 parse_extract_address(raw_sender, &errmess, &start, &end, &sender_domain,
1841 if (raw_sender == NULL)
1842 /* The function moan_smtp_batch() does not return. */
1843 moan_smtp_batch(smtp_cmd_buffer, "501 %s", errmess);
1845 sender_address = string_copy(raw_sender);
1847 /* Qualify unqualified sender addresses if permitted to do so. */
1849 if (sender_domain == 0 && sender_address[0] != 0 && sender_address[0] != '@')
1851 if (allow_unqualified_sender)
1853 sender_address = rewrite_address_qualify(sender_address, FALSE);
1854 DEBUG(D_receive) debug_printf("unqualified address %s accepted "
1855 "and rewritten\n", raw_sender);
1857 /* The function moan_smtp_batch() does not return. */
1858 else moan_smtp_batch(smtp_cmd_buffer, "501 sender address must contain "
1864 /* The RCPT TO command requires an address as an operand. All we do
1865 here is to parse it for syntactic correctness. There may be any number
1866 of RCPT TO commands, specifying multiple senders. We build them all into
1867 a data structure that is in argc/argv format. The start/end values
1868 given by parse_extract_address are not used, as we keep only the
1869 extracted address. */
1872 if (sender_address == NULL)
1873 /* The function moan_smtp_batch() does not return. */
1874 moan_smtp_batch(smtp_cmd_buffer, "503 No sender yet given");
1876 if (smtp_cmd_data[0] == 0)
1877 /* The function moan_smtp_batch() does not return. */
1878 moan_smtp_batch(smtp_cmd_buffer, "501 RCPT TO must have an address operand");
1880 /* Check maximum number allowed */
1882 if (recipients_max > 0 && recipients_count + 1 > recipients_max)
1883 /* The function moan_smtp_batch() does not return. */
1884 moan_smtp_batch(smtp_cmd_buffer, "%s too many recipients",
1885 recipients_max_reject? "552": "452");
1887 /* Apply SMTP rewrite, then extract address. Don't allow "<>" as a
1888 recipient address */
1890 recipient = rewrite_existflags & rewrite_smtp
1891 ? rewrite_one(smtp_cmd_data, rewrite_smtp, NULL, FALSE, US"",
1892 global_rewrite_rules)
1895 recipient = parse_extract_address(recipient, &errmess, &start, &end,
1896 &recipient_domain, FALSE);
1899 /* The function moan_smtp_batch() does not return. */
1900 moan_smtp_batch(smtp_cmd_buffer, "501 %s", errmess);
1902 /* If the recipient address is unqualified, qualify it if permitted. Then
1903 add it to the list of recipients. */
1905 if (recipient_domain == 0)
1907 if (allow_unqualified_recipient)
1909 DEBUG(D_receive) debug_printf("unqualified address %s accepted\n",
1911 recipient = rewrite_address_qualify(recipient, TRUE);
1913 /* The function moan_smtp_batch() does not return. */
1914 else moan_smtp_batch(smtp_cmd_buffer, "501 recipient address must contain "
1917 receive_add_recipient(recipient, -1);
1921 /* The DATA command is legal only if it follows successful MAIL FROM
1922 and RCPT TO commands. This function is complete when a valid DATA
1923 command is encountered. */
1926 if (sender_address == NULL || recipients_count <= 0)
1928 /* The function moan_smtp_batch() does not return. */
1929 if (sender_address == NULL)
1930 moan_smtp_batch(smtp_cmd_buffer,
1931 "503 MAIL FROM:<sender> command must precede DATA");
1933 moan_smtp_batch(smtp_cmd_buffer,
1934 "503 RCPT TO:<recipient> must precede DATA");
1938 done = 3; /* DATA successfully achieved */
1939 message_ended = END_NOTENDED; /* Indicate in middle of message */
1944 /* The VRFY, EXPN, HELP, ETRN, and NOOP commands are ignored. */
1951 bsmtp_transaction_linecount = receive_linecount;
1962 /* The function moan_smtp_batch() does not return. */
1963 moan_smtp_batch(smtp_cmd_buffer, "501 Unexpected argument data");
1968 /* The function moan_smtp_batch() does not return. */
1969 moan_smtp_batch(smtp_cmd_buffer, "501 Unexpected NULL in SMTP command");
1974 /* The function moan_smtp_batch() does not return. */
1975 moan_smtp_batch(smtp_cmd_buffer, "500 Command unrecognized");
1980 return done - 2; /* Convert yield values */
1986 /*************************************************
1987 * Start an SMTP session *
1988 *************************************************/
1990 /* This function is called at the start of an SMTP session. Thereafter,
1991 smtp_setup_msg() is called to initiate each separate message. This
1992 function does host-specific testing, and outputs the banner line.
1995 Returns: FALSE if the session can not continue; something has
1996 gone wrong, or the connection to the host is blocked
2000 smtp_start_session(void)
2004 uschar *user_msg, *log_msg;
2008 smtp_connection_start = time(NULL);
2009 for (smtp_ch_index = 0; smtp_ch_index < SMTP_HBUFF_SIZE; smtp_ch_index++)
2010 smtp_connection_had[smtp_ch_index] = SCH_NONE;
2013 /* Default values for certain variables */
2015 helo_seen = esmtp = helo_accept_junk = FALSE;
2016 smtp_mailcmd_count = 0;
2017 count_nonmail = TRUE_UNSET;
2018 synprot_error_count = unknown_command_count = nonmail_command_count = 0;
2019 smtp_delay_mail = smtp_rlm_base;
2020 auth_advertised = FALSE;
2021 pipelining_advertised = FALSE;
2022 pipelining_enable = TRUE;
2023 sync_cmd_limit = NON_SYNC_CMD_NON_PIPELINING;
2024 smtp_exit_function_called = FALSE; /* For avoiding loop in not-quit exit */
2026 /* If receiving by -bs from a trusted user, or testing with -bh, we allow
2027 authentication settings from -oMaa to remain in force. */
2029 if (!host_checking && !sender_host_notsocket) sender_host_authenticated = NULL;
2030 authenticated_by = NULL;
2033 tls_in.cipher = tls_in.peerdn = NULL;
2034 tls_in.ourcert = tls_in.peercert = NULL;
2036 tls_in.ocsp = OCSP_NOT_REQ;
2037 tls_advertised = FALSE;
2039 dsn_advertised = FALSE;
2041 smtputf8_advertised = FALSE;
2044 /* Reset ACL connection variables */
2048 /* Allow for trailing 0 in the command and data buffers. */
2050 if (!(smtp_cmd_buffer = US malloc(2*smtp_cmd_buffer_size + 2)))
2051 log_write(0, LOG_MAIN|LOG_PANIC_DIE,
2052 "malloc() failed for SMTP command buffer");
2054 smtp_cmd_buffer[0] = 0;
2055 smtp_data_buffer = smtp_cmd_buffer + smtp_cmd_buffer_size + 1;
2057 /* For batched input, the protocol setting can be overridden from the
2058 command line by a trusted caller. */
2060 if (smtp_batched_input)
2062 if (!received_protocol) received_protocol = US"local-bsmtp";
2065 /* For non-batched SMTP input, the protocol setting is forced here. It will be
2066 reset later if any of EHLO/AUTH/STARTTLS are received. */
2070 (sender_host_address ? protocols : protocols_local) [pnormal];
2072 /* Set up the buffer for inputting using direct read() calls, and arrange to
2073 call the local functions instead of the standard C ones. */
2075 if (!(smtp_inbuffer = (uschar *)malloc(in_buffer_size)))
2076 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "malloc() failed for SMTP input buffer");
2078 receive_getc = smtp_getc;
2079 receive_get_cache = smtp_get_cache;
2080 receive_ungetc = smtp_ungetc;
2081 receive_feof = smtp_feof;
2082 receive_ferror = smtp_ferror;
2083 receive_smtp_buffered = smtp_buffered;
2084 smtp_inptr = smtp_inend = smtp_inbuffer;
2085 smtp_had_eof = smtp_had_error = 0;
2087 /* Set up the message size limit; this may be host-specific */
2089 thismessage_size_limit = expand_string_integer(message_size_limit, TRUE);
2090 if (expand_string_message != NULL)
2092 if (thismessage_size_limit == -1)
2093 log_write(0, LOG_MAIN|LOG_PANIC, "unable to expand message_size_limit: "
2094 "%s", expand_string_message);
2096 log_write(0, LOG_MAIN|LOG_PANIC, "invalid message_size_limit: "
2097 "%s", expand_string_message);
2098 smtp_closedown(US"Temporary local problem - please try later");
2102 /* When a message is input locally via the -bs or -bS options, sender_host_
2103 unknown is set unless -oMa was used to force an IP address, in which case it
2104 is checked like a real remote connection. When -bs is used from inetd, this
2105 flag is not set, causing the sending host to be checked. The code that deals
2106 with IP source routing (if configured) is never required for -bs or -bS and
2107 the flag sender_host_notsocket is used to suppress it.
2109 If smtp_accept_max and smtp_accept_reserve are set, keep some connections in
2110 reserve for certain hosts and/or networks. */
2112 if (!sender_host_unknown)
2115 BOOL reserved_host = FALSE;
2117 /* Look up IP options (source routing info) on the socket if this is not an
2118 -oMa "host", and if any are found, log them and drop the connection.
2120 Linux (and others now, see below) is different to everyone else, so there
2121 has to be some conditional compilation here. Versions of Linux before 2.1.15
2122 used a structure whose name was "options". Somebody finally realized that
2123 this name was silly, and it got changed to "ip_options". I use the
2124 newer name here, but there is a fudge in the script that sets up os.h
2125 to define a macro in older Linux systems.
2127 Sigh. Linux is a fast-moving target. Another generation of Linux uses
2128 glibc 2, which has chosen ip_opts for the structure name. This is now
2129 really a glibc thing rather than a Linux thing, so the condition name
2130 has been changed to reflect this. It is relevant also to GNU/Hurd.
2132 Mac OS 10.x (Darwin) is like the later glibc versions, but without the
2133 setting of the __GLIBC__ macro, so we can't detect it automatically. There's
2134 a special macro defined in the os.h file.
2136 Some DGUX versions on older hardware appear not to support IP options at
2137 all, so there is now a general macro which can be set to cut out this
2140 How to do this properly in IPv6 is not yet known. */
2142 #if !HAVE_IPV6 && !defined(NO_IP_OPTIONS)
2144 #ifdef GLIBC_IP_OPTIONS
2145 #if (!defined __GLIBC__) || (__GLIBC__ < 2)
2150 #elif defined DARWIN_IP_OPTIONS
2156 if (!host_checking && !sender_host_notsocket)
2159 EXIM_SOCKLEN_T optlen = sizeof(struct ip_options) + MAX_IPOPTLEN;
2160 struct ip_options *ipopt = store_get(optlen);
2162 struct ip_opts ipoptblock;
2163 struct ip_opts *ipopt = &ipoptblock;
2164 EXIM_SOCKLEN_T optlen = sizeof(ipoptblock);
2166 struct ipoption ipoptblock;
2167 struct ipoption *ipopt = &ipoptblock;
2168 EXIM_SOCKLEN_T optlen = sizeof(ipoptblock);
2171 /* Occasional genuine failures of getsockopt() have been seen - for
2172 example, "reset by peer". Therefore, just log and give up on this
2173 call, unless the error is ENOPROTOOPT. This error is given by systems
2174 that have the interfaces but not the mechanism - e.g. GNU/Hurd at the time
2175 of writing. So for that error, carry on - we just can't do an IP options
2178 DEBUG(D_receive) debug_printf("checking for IP options\n");
2180 if (getsockopt(fileno(smtp_out), IPPROTO_IP, IP_OPTIONS, (uschar *)(ipopt),
2183 if (errno != ENOPROTOOPT)
2185 log_write(0, LOG_MAIN, "getsockopt() failed from %s: %s",
2186 host_and_ident(FALSE), strerror(errno));
2187 smtp_printf("451 SMTP service not available\r\n");
2192 /* Deal with any IP options that are set. On the systems I have looked at,
2193 the value of MAX_IPOPTLEN has been 40, meaning that there should never be
2194 more logging data than will fit in big_buffer. Nevertheless, after somebody
2195 questioned this code, I've added in some paranoid checking. */
2197 else if (optlen > 0)
2199 uschar *p = big_buffer;
2200 uschar *pend = big_buffer + big_buffer_size;
2201 uschar *opt, *adptr;
2203 struct in_addr addr;
2206 uschar *optstart = (uschar *)(ipopt->__data);
2208 uschar *optstart = (uschar *)(ipopt->ip_opts);
2210 uschar *optstart = (uschar *)(ipopt->ipopt_list);
2213 DEBUG(D_receive) debug_printf("IP options exist\n");
2215 Ustrcpy(p, "IP options on incoming call:");
2218 for (opt = optstart; opt != NULL &&
2219 opt < (uschar *)(ipopt) + optlen;)
2233 if (!string_format(p, pend-p, " %s [@%s",
2234 (*opt == IPOPT_SSRR)? "SSRR" : "LSRR",
2236 inet_ntoa(*((struct in_addr *)(&(ipopt->faddr))))))
2238 inet_ntoa(ipopt->ip_dst)))
2240 inet_ntoa(ipopt->ipopt_dst)))
2248 optcount = (opt[1] - 3) / sizeof(struct in_addr);
2250 while (optcount-- > 0)
2252 memcpy(&addr, adptr, sizeof(addr));
2253 if (!string_format(p, pend - p - 1, "%s%s",
2254 (optcount == 0)? ":" : "@", inet_ntoa(addr)))
2260 adptr += sizeof(struct in_addr);
2269 if (pend - p < 4 + 3*opt[1]) { opt = NULL; break; }
2272 for (i = 0; i < opt[1]; i++)
2274 sprintf(CS p, "%2.2x ", opt[i]);
2285 log_write(0, LOG_MAIN, "%s", big_buffer);
2287 /* Refuse any call with IP options. This is what tcpwrappers 7.5 does. */
2289 log_write(0, LOG_MAIN|LOG_REJECT,
2290 "connection from %s refused (IP options)", host_and_ident(FALSE));
2292 smtp_printf("554 SMTP service not available\r\n");
2296 /* Length of options = 0 => there are no options */
2298 else DEBUG(D_receive) debug_printf("no IP options found\n");
2300 #endif /* HAVE_IPV6 && !defined(NO_IP_OPTIONS) */
2302 /* Set keep-alive in socket options. The option is on by default. This
2303 setting is an attempt to get rid of some hanging connections that stick in
2304 read() when the remote end (usually a dialup) goes away. */
2306 if (smtp_accept_keepalive && !sender_host_notsocket)
2307 ip_keepalive(fileno(smtp_out), sender_host_address, FALSE);
2309 /* If the current host matches host_lookup, set the name by doing a
2310 reverse lookup. On failure, sender_host_name will be NULL and
2311 host_lookup_failed will be TRUE. This may or may not be serious - optional
2314 if (verify_check_host(&host_lookup) == OK)
2316 (void)host_name_lookup();
2317 host_build_sender_fullhost();
2320 /* Delay this until we have the full name, if it is looked up. */
2322 set_process_info("handling incoming connection from %s",
2323 host_and_ident(FALSE));
2325 /* Expand smtp_receive_timeout, if needed */
2327 if (smtp_receive_timeout_s)
2330 if ( !(exp = expand_string(smtp_receive_timeout_s))
2332 || (smtp_receive_timeout = readconf_readtime(exp, 0, FALSE)) < 0
2334 log_write(0, LOG_MAIN|LOG_PANIC,
2335 "bad value for smtp_receive_timeout: '%s'", exp ? exp : US"");
2338 /* Start up TLS if tls_on_connect is set. This is for supporting the legacy
2339 smtps port for use with older style SSL MTAs. */
2342 if (tls_in.on_connect && tls_server_start(tls_require_ciphers) != OK)
2346 /* Test for explicit connection rejection */
2348 if (verify_check_host(&host_reject_connection) == OK)
2350 log_write(L_connection_reject, LOG_MAIN|LOG_REJECT, "refused connection "
2351 "from %s (host_reject_connection)", host_and_ident(FALSE));
2352 smtp_printf("554 SMTP service not available\r\n");
2356 /* Test with TCP Wrappers if so configured. There is a problem in that
2357 hosts_ctl() returns 0 (deny) under a number of system failure circumstances,
2358 such as disks dying. In these cases, it is desirable to reject with a 4xx
2359 error instead of a 5xx error. There isn't a "right" way to detect such
2360 problems. The following kludge is used: errno is zeroed before calling
2361 hosts_ctl(). If the result is "reject", a 5xx error is given only if the
2362 value of errno is 0 or ENOENT (which happens if /etc/hosts.{allow,deny} does
2365 #ifdef USE_TCP_WRAPPERS
2367 tcp_wrappers_name = expand_string(tcp_wrappers_daemon_name);
2368 if (tcp_wrappers_name == NULL)
2370 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "Expansion of \"%s\" "
2371 "(tcp_wrappers_name) failed: %s", string_printing(tcp_wrappers_name),
2372 expand_string_message);
2374 if (!hosts_ctl(tcp_wrappers_name,
2375 (sender_host_name == NULL)? STRING_UNKNOWN : CS sender_host_name,
2376 (sender_host_address == NULL)? STRING_UNKNOWN : CS sender_host_address,
2377 (sender_ident == NULL)? STRING_UNKNOWN : CS sender_ident))
2379 if (errno == 0 || errno == ENOENT)
2381 HDEBUG(D_receive) debug_printf("tcp wrappers rejection\n");
2382 log_write(L_connection_reject,
2383 LOG_MAIN|LOG_REJECT, "refused connection from %s "
2384 "(tcp wrappers)", host_and_ident(FALSE));
2385 smtp_printf("554 SMTP service not available\r\n");
2389 int save_errno = errno;
2390 HDEBUG(D_receive) debug_printf("tcp wrappers rejected with unexpected "
2391 "errno value %d\n", save_errno);
2392 log_write(L_connection_reject,
2393 LOG_MAIN|LOG_REJECT, "temporarily refused connection from %s "
2394 "(tcp wrappers errno=%d)", host_and_ident(FALSE), save_errno);
2395 smtp_printf("451 Temporary local problem - please try later\r\n");
2401 /* Check for reserved slots. The value of smtp_accept_count has already been
2402 incremented to include this process. */
2404 if (smtp_accept_max > 0 &&
2405 smtp_accept_count > smtp_accept_max - smtp_accept_reserve)
2407 if ((rc = verify_check_host(&smtp_reserve_hosts)) != OK)
2409 log_write(L_connection_reject,
2410 LOG_MAIN, "temporarily refused connection from %s: not in "
2411 "reserve list: connected=%d max=%d reserve=%d%s",
2412 host_and_ident(FALSE), smtp_accept_count - 1, smtp_accept_max,
2413 smtp_accept_reserve, (rc == DEFER)? " (lookup deferred)" : "");
2414 smtp_printf("421 %s: Too many concurrent SMTP connections; "
2415 "please try again later\r\n", smtp_active_hostname);
2418 reserved_host = TRUE;
2421 /* If a load level above which only messages from reserved hosts are
2422 accepted is set, check the load. For incoming calls via the daemon, the
2423 check is done in the superior process if there are no reserved hosts, to
2424 save a fork. In all cases, the load average will already be available
2425 in a global variable at this point. */
2427 if (smtp_load_reserve >= 0 &&
2428 load_average > smtp_load_reserve &&
2430 verify_check_host(&smtp_reserve_hosts) != OK)
2432 log_write(L_connection_reject,
2433 LOG_MAIN, "temporarily refused connection from %s: not in "
2434 "reserve list and load average = %.2f", host_and_ident(FALSE),
2435 (double)load_average/1000.0);
2436 smtp_printf("421 %s: Too much load; please try again later\r\n",
2437 smtp_active_hostname);
2441 /* Determine whether unqualified senders or recipients are permitted
2442 for this host. Unfortunately, we have to do this every time, in order to
2443 set the flags so that they can be inspected when considering qualifying
2444 addresses in the headers. For a site that permits no qualification, this
2445 won't take long, however. */
2447 allow_unqualified_sender =
2448 verify_check_host(&sender_unqualified_hosts) == OK;
2450 allow_unqualified_recipient =
2451 verify_check_host(&recipient_unqualified_hosts) == OK;
2453 /* Determine whether HELO/EHLO is required for this host. The requirement
2454 can be hard or soft. */
2456 helo_required = verify_check_host(&helo_verify_hosts) == OK;
2458 helo_verify = verify_check_host(&helo_try_verify_hosts) == OK;
2460 /* Determine whether this hosts is permitted to send syntactic junk
2461 after a HELO or EHLO command. */
2463 helo_accept_junk = verify_check_host(&helo_accept_junk_hosts) == OK;
2466 /* For batch SMTP input we are now done. */
2468 if (smtp_batched_input) return TRUE;
2470 #ifdef SUPPORT_PROXY
2471 /* If valid Proxy Protocol source is connecting, set up session.
2472 * Failure will not allow any SMTP function other than QUIT. */
2473 proxy_session = FALSE;
2474 proxy_session_failed = FALSE;
2475 if (check_proxy_protocol_host())
2477 if (setup_proxy_protocol_host() == FALSE)
2479 proxy_session_failed = TRUE;
2481 debug_printf("Failure to extract proxied host, only QUIT allowed\n");
2485 sender_host_name = NULL;
2486 (void)host_name_lookup();
2487 host_build_sender_fullhost();
2492 /* Run the ACL if it exists */
2495 if (acl_smtp_connect != NULL)
2498 rc = acl_check(ACL_WHERE_CONNECT, NULL, acl_smtp_connect, &user_msg,
2502 (void)smtp_handle_acl_fail(ACL_WHERE_CONNECT, rc, user_msg, log_msg);
2507 /* Output the initial message for a two-way SMTP connection. It may contain
2508 newlines, which then cause a multi-line response to be given. */
2510 code = US"220"; /* Default status code */
2511 esc = US""; /* Default extended status code */
2512 esclen = 0; /* Length of esc */
2516 if (!(s = expand_string(smtp_banner)))
2517 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "Expansion of \"%s\" (smtp_banner) "
2518 "failed: %s", smtp_banner, expand_string_message);
2524 smtp_message_code(&code, &codelen, &s, NULL, TRUE);
2528 esclen = codelen - 4;
2532 /* Remove any terminating newlines; might as well remove trailing space too */
2535 while (p > s && isspace(p[-1])) p--;
2538 /* It seems that CC:Mail is braindead, and assumes that the greeting message
2539 is all contained in a single IP packet. The original code wrote out the
2540 greeting using several calls to fprint/fputc, and on busy servers this could
2541 cause it to be split over more than one packet - which caused CC:Mail to fall
2542 over when it got the second part of the greeting after sending its first
2543 command. Sigh. To try to avoid this, build the complete greeting message
2544 first, and output it in one fell swoop. This gives a better chance of it
2545 ending up as a single packet. */
2547 ss = store_get(size);
2551 do /* At least once, in case we have an empty string */
2554 uschar *linebreak = Ustrchr(p, '\n');
2555 ss = string_catn(ss, &size, &ptr, code, 3);
2556 if (linebreak == NULL)
2559 ss = string_catn(ss, &size, &ptr, US" ", 1);
2563 len = linebreak - p;
2564 ss = string_catn(ss, &size, &ptr, US"-", 1);
2566 ss = string_catn(ss, &size, &ptr, esc, esclen);
2567 ss = string_catn(ss, &size, &ptr, p, len);
2568 ss = string_catn(ss, &size, &ptr, US"\r\n", 2);
2570 if (linebreak != NULL) p++;
2574 ss[ptr] = 0; /* string_cat leaves room for this */
2576 /* Before we write the banner, check that there is no input pending, unless
2577 this synchronisation check is disabled. */
2581 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP protocol "
2582 "synchronization error (input sent without waiting for greeting): "
2583 "rejected connection from %s input=\"%s\"", host_and_ident(TRUE),
2584 string_printing(smtp_inptr));
2585 smtp_printf("554 SMTP synchronization error\r\n");
2589 /* Now output the banner */
2591 smtp_printf("%s", ss);
2599 /*************************************************
2600 * Handle SMTP syntax and protocol errors *
2601 *************************************************/
2603 /* Write to the log for SMTP syntax errors in incoming commands, if configured
2604 to do so. Then transmit the error response. The return value depends on the
2605 number of syntax and protocol errors in this SMTP session.
2608 type error type, given as a log flag bit
2609 code response code; <= 0 means don't send a response
2610 data data to reflect in the response (can be NULL)
2611 errmess the error message
2613 Returns: -1 limit of syntax/protocol errors NOT exceeded
2614 +1 limit of syntax/protocol errors IS exceeded
2616 These values fit in with the values of the "done" variable in the main
2617 processing loop in smtp_setup_msg(). */
2620 synprot_error(int type, int code, uschar *data, uschar *errmess)
2624 log_write(type, LOG_MAIN, "SMTP %s error in \"%s\" %s %s",
2625 (type == L_smtp_syntax_error)? "syntax" : "protocol",
2626 string_printing(smtp_cmd_buffer), host_and_ident(TRUE), errmess);
2628 if (++synprot_error_count > smtp_max_synprot_errors)
2631 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
2632 "syntax or protocol errors (last command was \"%s\")",
2633 host_and_ident(FALSE), string_printing(smtp_cmd_buffer));
2638 smtp_printf("%d%c%s%s%s\r\n", code, (yield == 1)? '-' : ' ',
2639 (data == NULL)? US"" : data, (data == NULL)? US"" : US": ", errmess);
2641 smtp_printf("%d Too many syntax or protocol errors\r\n", code);
2650 /*************************************************
2651 * Log incomplete transactions *
2652 *************************************************/
2654 /* This function is called after a transaction has been aborted by RSET, QUIT,
2655 connection drops or other errors. It logs the envelope information received
2656 so far in order to preserve address verification attempts.
2658 Argument: string to indicate what aborted the transaction
2663 incomplete_transaction_log(uschar *what)
2665 if (sender_address == NULL || /* No transaction in progress */
2666 !LOGGING(smtp_incomplete_transaction))
2669 /* Build list of recipients for logging */
2671 if (recipients_count > 0)
2674 raw_recipients = store_get(recipients_count * sizeof(uschar *));
2675 for (i = 0; i < recipients_count; i++)
2676 raw_recipients[i] = recipients_list[i].address;
2677 raw_recipients_count = recipients_count;
2680 log_write(L_smtp_incomplete_transaction, LOG_MAIN|LOG_SENDER|LOG_RECIPIENTS,
2681 "%s incomplete transaction (%s)", host_and_ident(TRUE), what);
2687 /*************************************************
2688 * Send SMTP response, possibly multiline *
2689 *************************************************/
2691 /* There are, it seems, broken clients out there that cannot handle multiline
2692 responses. If no_multiline_responses is TRUE (it can be set from an ACL), we
2693 output nothing for non-final calls, and only the first line for anything else.
2696 code SMTP code, may involve extended status codes
2697 codelen length of smtp code; if > 4 there's an ESC
2698 final FALSE if the last line isn't the final line
2699 msg message text, possibly containing newlines
2705 smtp_respond(uschar* code, int codelen, BOOL final, uschar *msg)
2710 if (!final && no_multiline_responses) return;
2715 esclen = codelen - 4;
2718 /* If this is the first output for a (non-batch) RCPT command, see if all RCPTs
2719 have had the same. Note: this code is also present in smtp_printf(). It would
2720 be tidier to have it only in one place, but when it was added, it was easier to
2721 do it that way, so as not to have to mess with the code for the RCPT command,
2722 which sometimes uses smtp_printf() and sometimes smtp_respond(). */
2724 if (rcpt_in_progress)
2726 if (rcpt_smtp_response == NULL)
2727 rcpt_smtp_response = string_copy(msg);
2728 else if (rcpt_smtp_response_same &&
2729 Ustrcmp(rcpt_smtp_response, msg) != 0)
2730 rcpt_smtp_response_same = FALSE;
2731 rcpt_in_progress = FALSE;
2734 /* Not output the message, splitting it up into multiple lines if necessary. */
2738 uschar *nl = Ustrchr(msg, '\n');
2741 smtp_printf("%.3s%c%.*s%s\r\n", code, final? ' ':'-', esclen, esc, msg);
2744 else if (nl[1] == 0 || no_multiline_responses)
2746 smtp_printf("%.3s%c%.*s%.*s\r\n", code, final? ' ':'-', esclen, esc,
2747 (int)(nl - msg), msg);
2752 smtp_printf("%.3s-%.*s%.*s\r\n", code, esclen, esc, (int)(nl - msg), msg);
2754 while (isspace(*msg)) msg++;
2762 /*************************************************
2763 * Parse user SMTP message *
2764 *************************************************/
2766 /* This function allows for user messages overriding the response code details
2767 by providing a suitable response code string at the start of the message
2768 user_msg. Check the message for starting with a response code and optionally an
2769 extended status code. If found, check that the first digit is valid, and if so,
2770 change the code pointer and length to use the replacement. An invalid code
2771 causes a panic log; in this case, if the log messages is the same as the user
2772 message, we must also adjust the value of the log message to show the code that
2773 is actually going to be used (the original one).
2775 This function is global because it is called from receive.c as well as within
2778 Note that the code length returned includes the terminating whitespace
2779 character, which is always included in the regex match.
2782 code SMTP code, may involve extended status codes
2783 codelen length of smtp code; if > 4 there's an ESC
2785 log_msg optional log message, to be adjusted with the new SMTP code
2786 check_valid if true, verify the response code
2792 smtp_message_code(uschar **code, int *codelen, uschar **msg, uschar **log_msg,
2798 if (!msg || !*msg) return;
2800 if ((n = pcre_exec(regex_smtp_code, NULL, CS *msg, Ustrlen(*msg), 0,
2801 PCRE_EOPT, ovector, sizeof(ovector)/sizeof(int))) < 0) return;
2803 if (check_valid && (*msg)[0] != (*code)[0])
2805 log_write(0, LOG_MAIN|LOG_PANIC, "configured error code starts with "
2806 "incorrect digit (expected %c) in \"%s\"", (*code)[0], *msg);
2807 if (log_msg != NULL && *log_msg == *msg)
2808 *log_msg = string_sprintf("%s %s", *code, *log_msg + ovector[1]);
2813 *codelen = ovector[1]; /* Includes final space */
2815 *msg += ovector[1]; /* Chop the code off the message */
2822 /*************************************************
2823 * Handle an ACL failure *
2824 *************************************************/
2826 /* This function is called when acl_check() fails. As well as calls from within
2827 this module, it is called from receive.c for an ACL after DATA. It sorts out
2828 logging the incident, and sets up the error response. A message containing
2829 newlines is turned into a multiline SMTP response, but for logging, only the
2832 There's a table of default permanent failure response codes to use in
2833 globals.c, along with the table of names. VFRY is special. Despite RFC1123 it
2834 defaults disabled in Exim. However, discussion in connection with RFC 821bis
2835 (aka RFC 2821) has concluded that the response should be 252 in the disabled
2836 state, because there are broken clients that try VRFY before RCPT. A 5xx
2837 response should be given only when the address is positively known to be
2838 undeliverable. Sigh. We return 252 if there is no VRFY ACL or it provides
2839 no explicit code, but if there is one we let it know best.
2840 Also, for ETRN, 458 is given on refusal, and for AUTH, 503.
2842 From Exim 4.63, it is possible to override the response code details by
2843 providing a suitable response code string at the start of the message provided
2844 in user_msg. The code's first digit is checked for validity.
2847 where where the ACL was called from
2849 user_msg a message that can be included in an SMTP response
2850 log_msg a message for logging
2852 Returns: 0 in most cases
2853 2 if the failure code was FAIL_DROP, in which case the
2854 SMTP connection should be dropped (this value fits with the
2855 "done" variable in smtp_setup_msg() below)
2859 smtp_handle_acl_fail(int where, int rc, uschar *user_msg, uschar *log_msg)
2861 BOOL drop = rc == FAIL_DROP;
2865 uschar *sender_info = US"";
2867 #ifdef WITH_CONTENT_SCAN
2868 (where == ACL_WHERE_MIME)? US"during MIME ACL checks" :
2870 (where == ACL_WHERE_PREDATA)? US"DATA" :
2871 (where == ACL_WHERE_DATA)? US"after DATA" :
2872 #ifndef DISABLE_PRDR
2873 (where == ACL_WHERE_PRDR)? US"after DATA PRDR" :
2875 (smtp_cmd_data == NULL)?
2876 string_sprintf("%s in \"connect\" ACL", acl_wherenames[where]) :
2877 string_sprintf("%s %s", acl_wherenames[where], smtp_cmd_data);
2879 if (drop) rc = FAIL;
2881 /* Set the default SMTP code, and allow a user message to change it. */
2883 smtp_code = rc == FAIL ? acl_wherecodes[where] : US"451";
2884 smtp_message_code(&smtp_code, &codelen, &user_msg, &log_msg,
2885 where != ACL_WHERE_VRFY);
2887 /* We used to have sender_address here; however, there was a bug that was not
2888 updating sender_address after a rewrite during a verify. When this bug was
2889 fixed, sender_address at this point became the rewritten address. I'm not sure
2890 this is what should be logged, so I've changed to logging the unrewritten
2891 address to retain backward compatibility. */
2893 #ifndef WITH_CONTENT_SCAN
2894 if (where == ACL_WHERE_RCPT || where == ACL_WHERE_DATA)
2896 if (where == ACL_WHERE_RCPT || where == ACL_WHERE_DATA || where == ACL_WHERE_MIME)
2899 sender_info = string_sprintf("F=<%s>%s%s%s%s ",
2900 sender_address_unrewritten ? sender_address_unrewritten : sender_address,
2901 sender_host_authenticated ? US" A=" : US"",
2902 sender_host_authenticated ? sender_host_authenticated : US"",
2903 sender_host_authenticated && authenticated_id ? US":" : US"",
2904 sender_host_authenticated && authenticated_id ? authenticated_id : US""
2908 /* If there's been a sender verification failure with a specific message, and
2909 we have not sent a response about it yet, do so now, as a preliminary line for
2910 failures, but not defers. However, always log it for defer, and log it for fail
2911 unless the sender_verify_fail log selector has been turned off. */
2913 if (sender_verified_failed != NULL &&
2914 !testflag(sender_verified_failed, af_sverify_told))
2916 BOOL save_rcpt_in_progress = rcpt_in_progress;
2917 rcpt_in_progress = FALSE; /* So as not to treat these as the error */
2919 setflag(sender_verified_failed, af_sverify_told);
2921 if (rc != FAIL || LOGGING(sender_verify_fail))
2922 log_write(0, LOG_MAIN|LOG_REJECT, "%s sender verify %s for <%s>%s",
2923 host_and_ident(TRUE),
2924 ((sender_verified_failed->special_action & 255) == DEFER)? "defer":"fail",
2925 sender_verified_failed->address,
2926 (sender_verified_failed->message == NULL)? US"" :
2927 string_sprintf(": %s", sender_verified_failed->message));
2929 if (rc == FAIL && sender_verified_failed->user_message != NULL)
2930 smtp_respond(smtp_code, codelen, FALSE, string_sprintf(
2931 testflag(sender_verified_failed, af_verify_pmfail)?
2932 "Postmaster verification failed while checking <%s>\n%s\n"
2933 "Several RFCs state that you are required to have a postmaster\n"
2934 "mailbox for each mail domain. This host does not accept mail\n"
2935 "from domains whose servers reject the postmaster address."
2937 testflag(sender_verified_failed, af_verify_nsfail)?
2938 "Callback setup failed while verifying <%s>\n%s\n"
2939 "The initial connection, or a HELO or MAIL FROM:<> command was\n"
2940 "rejected. Refusing MAIL FROM:<> does not help fight spam, disregards\n"
2941 "RFC requirements, and stops you from receiving standard bounce\n"
2942 "messages. This host does not accept mail from domains whose servers\n"
2945 "Verification failed for <%s>\n%s",
2946 sender_verified_failed->address,
2947 sender_verified_failed->user_message));
2949 rcpt_in_progress = save_rcpt_in_progress;
2952 /* Sort out text for logging */
2954 log_msg = (log_msg == NULL)? US"" : string_sprintf(": %s", log_msg);
2955 lognl = Ustrchr(log_msg, '\n');
2956 if (lognl != NULL) *lognl = 0;
2958 /* Send permanent failure response to the command, but the code used isn't
2959 always a 5xx one - see comments at the start of this function. If the original
2960 rc was FAIL_DROP we drop the connection and yield 2. */
2963 smtp_respond(smtp_code, codelen, TRUE,
2964 user_msg ? user_msg : US"Administrative prohibition");
2966 /* Send temporary failure response to the command. Don't give any details,
2967 unless acl_temp_details is set. This is TRUE for a callout defer, a "defer"
2968 verb, and for a header verify when smtp_return_error_details is set.
2970 This conditional logic is all somewhat of a mess because of the odd
2971 interactions between temp_details and return_error_details. One day it should
2972 be re-implemented in a tidier fashion. */
2975 if (acl_temp_details && user_msg)
2977 if ( smtp_return_error_details
2978 && sender_verified_failed
2979 && sender_verified_failed->message
2981 smtp_respond(smtp_code, codelen, FALSE, sender_verified_failed->message);
2983 smtp_respond(smtp_code, codelen, TRUE, user_msg);
2986 smtp_respond(smtp_code, codelen, TRUE,
2987 US"Temporary local problem - please try later");
2989 /* Log the incident to the logs that are specified by log_reject_target
2990 (default main, reject). This can be empty to suppress logging of rejections. If
2991 the connection is not forcibly to be dropped, return 0. Otherwise, log why it
2992 is closing if required and return 2. */
2994 if (log_reject_target != 0)
2997 uschar * tls = s_tlslog(NULL, NULL, NULL);
2998 if (!tls) tls = US"";
3000 uschar * tls = US"";
3002 log_write(0, log_reject_target, "%s%s%s %s%srejected %s%s",
3003 LOGGING(dnssec) && sender_host_dnssec ? US" DS" : US"",
3004 host_and_ident(TRUE),
3007 rc == FAIL ? US"" : US"temporarily ",
3011 if (!drop) return 0;
3013 log_write(L_smtp_connection, LOG_MAIN, "%s closed by DROP in ACL",
3014 smtp_get_connection_info());
3016 /* Run the not-quit ACL, but without any custom messages. This should not be a
3017 problem, because we get here only if some other ACL has issued "drop", and
3018 in that case, *its* custom messages will have been used above. */
3020 smtp_notquit_exit(US"acl-drop", NULL, NULL);
3027 /*************************************************
3028 * Handle SMTP exit when QUIT is not given *
3029 *************************************************/
3031 /* This function provides a logging/statistics hook for when an SMTP connection
3032 is dropped on the floor or the other end goes away. It's a global function
3033 because it's called from receive.c as well as this module. As well as running
3034 the NOTQUIT ACL, if there is one, this function also outputs a final SMTP
3035 response, either with a custom message from the ACL, or using a default. There
3036 is one case, however, when no message is output - after "drop". In that case,
3037 the ACL that obeyed "drop" has already supplied the custom message, and NULL is
3038 passed to this function.
3040 In case things go wrong while processing this function, causing an error that
3041 may re-enter this funtion, there is a recursion check.
3044 reason What $smtp_notquit_reason will be set to in the ACL;
3045 if NULL, the ACL is not run
3046 code The error code to return as part of the response
3047 defaultrespond The default message if there's no user_msg
3053 smtp_notquit_exit(uschar *reason, uschar *code, uschar *defaultrespond, ...)
3056 uschar *user_msg = NULL;
3057 uschar *log_msg = NULL;
3059 /* Check for recursive acll */
3061 if (smtp_exit_function_called)
3063 log_write(0, LOG_PANIC, "smtp_notquit_exit() called more than once (%s)",
3067 smtp_exit_function_called = TRUE;
3069 /* Call the not-QUIT ACL, if there is one, unless no reason is given. */
3071 if (acl_smtp_notquit && reason)
3073 smtp_notquit_reason = reason;
3074 if ((rc = acl_check(ACL_WHERE_NOTQUIT, NULL, acl_smtp_notquit, &user_msg,
3075 &log_msg)) == ERROR)
3076 log_write(0, LOG_MAIN|LOG_PANIC, "ACL for not-QUIT returned ERROR: %s",
3080 /* Write an SMTP response if we are expected to give one. As the default
3081 responses are all internal, they should always fit in the buffer, but code a
3082 warning, just in case. Note that string_vformat() still leaves a complete
3083 string, even if it is incomplete. */
3085 if (code && defaultrespond)
3088 smtp_respond(code, 3, TRUE, user_msg);
3093 va_start(ap, defaultrespond);
3094 if (!string_vformat(buffer, sizeof(buffer), CS defaultrespond, ap))
3095 log_write(0, LOG_MAIN|LOG_PANIC, "string too large in smtp_notquit_exit()");
3096 smtp_printf("%s %s\r\n", code, buffer);
3106 /*************************************************
3107 * Verify HELO argument *
3108 *************************************************/
3110 /* This function is called if helo_verify_hosts or helo_try_verify_hosts is
3111 matched. It is also called from ACL processing if verify = helo is used and
3112 verification was not previously tried (i.e. helo_try_verify_hosts was not
3113 matched). The result of its processing is to set helo_verified and
3114 helo_verify_failed. These variables should both be FALSE for this function to
3117 Note that EHLO/HELO is legitimately allowed to quote an address literal. Allow
3118 for IPv6 ::ffff: literals.
3121 Returns: TRUE if testing was completed;
3122 FALSE on a temporary failure
3126 smtp_verify_helo(void)
3130 HDEBUG(D_receive) debug_printf("verifying EHLO/HELO argument \"%s\"\n",
3133 if (sender_helo_name == NULL)
3135 HDEBUG(D_receive) debug_printf("no EHLO/HELO command was issued\n");
3138 /* Deal with the case of -bs without an IP address */
3140 else if (sender_host_address == NULL)
3142 HDEBUG(D_receive) debug_printf("no client IP address: assume success\n");
3143 helo_verified = TRUE;
3146 /* Deal with the more common case when there is a sending IP address */
3148 else if (sender_helo_name[0] == '[')
3150 helo_verified = Ustrncmp(sender_helo_name+1, sender_host_address,
3151 Ustrlen(sender_host_address)) == 0;
3156 if (strncmpic(sender_host_address, US"::ffff:", 7) == 0)
3157 helo_verified = Ustrncmp(sender_helo_name + 1,
3158 sender_host_address + 7, Ustrlen(sender_host_address) - 7) == 0;
3163 { if (helo_verified) debug_printf("matched host address\n"); }
3166 /* Do a reverse lookup if one hasn't already given a positive or negative
3167 response. If that fails, or the name doesn't match, try checking with a forward
3172 if (sender_host_name == NULL && !host_lookup_failed)
3173 yield = host_name_lookup() != DEFER;
3175 /* If a host name is known, check it and all its aliases. */
3177 if (sender_host_name)
3178 if ((helo_verified = strcmpic(sender_host_name, sender_helo_name) == 0))
3180 sender_helo_dnssec = sender_host_dnssec;
3181 HDEBUG(D_receive) debug_printf("matched host name\n");
3185 uschar **aliases = sender_host_aliases;
3187 if ((helo_verified = strcmpic(*aliases++, sender_helo_name) == 0))
3189 sender_helo_dnssec = sender_host_dnssec;
3193 HDEBUG(D_receive) if (helo_verified)
3194 debug_printf("matched alias %s\n", *(--aliases));
3197 /* Final attempt: try a forward lookup of the helo name */
3206 h.name = sender_helo_name;
3213 HDEBUG(D_receive) debug_printf("getting IP address for %s\n",
3215 rc = host_find_bydns(&h, NULL, HOST_FIND_BY_A,
3216 NULL, NULL, NULL, &d, NULL, NULL);
3217 if (rc == HOST_FOUND || rc == HOST_FOUND_LOCAL)
3218 for (hh = &h; hh; hh = hh->next)
3219 if (Ustrcmp(hh->address, sender_host_address) == 0)
3221 helo_verified = TRUE;
3222 if (h.dnssec == DS_YES) sender_helo_dnssec = TRUE;
3225 debug_printf("IP address for %s matches calling address\n"
3226 "Forward DNS security status: %sverified\n",
3227 sender_helo_name, sender_helo_dnssec ? "" : "un");
3234 if (!helo_verified) helo_verify_failed = TRUE; /* We've tried ... */
3241 /*************************************************
3242 * Send user response message *
3243 *************************************************/
3245 /* This function is passed a default response code and a user message. It calls
3246 smtp_message_code() to check and possibly modify the response code, and then
3247 calls smtp_respond() to transmit the response. I put this into a function
3248 just to avoid a lot of repetition.
3251 code the response code
3252 user_msg the user message
3258 smtp_user_msg(uschar *code, uschar *user_msg)
3261 smtp_message_code(&code, &len, &user_msg, NULL, TRUE);
3262 smtp_respond(code, len, TRUE, user_msg);
3268 smtp_in_auth(auth_instance *au, uschar ** s, uschar ** ss)
3270 const uschar *set_id = NULL;
3273 /* Run the checking code, passing the remainder of the command line as
3274 data. Initials the $auth<n> variables as empty. Initialize $0 empty and set
3275 it as the only set numerical variable. The authenticator may set $auth<n>
3276 and also set other numeric variables. The $auth<n> variables are preferred
3277 nowadays; the numerical variables remain for backwards compatibility.
3279 Afterwards, have a go at expanding the set_id string, even if
3280 authentication failed - for bad passwords it can be useful to log the
3281 userid. On success, require set_id to expand and exist, and put it in
3282 authenticated_id. Save this in permanent store, as the working store gets
3283 reset at HELO, RSET, etc. */
3285 for (i = 0; i < AUTH_VARS; i++) auth_vars[i] = NULL;
3287 expand_nlength[0] = 0; /* $0 contains nothing */
3289 rc = (au->info->servercode)(au, smtp_cmd_data);
3290 if (au->set_id) set_id = expand_string(au->set_id);
3291 expand_nmax = -1; /* Reset numeric variables */
3292 for (i = 0; i < AUTH_VARS; i++) auth_vars[i] = NULL; /* Reset $auth<n> */
3294 /* The value of authenticated_id is stored in the spool file and printed in
3295 log lines. It must not contain binary zeros or newline characters. In
3296 normal use, it never will, but when playing around or testing, this error
3297 can (did) happen. To guard against this, ensure that the id contains only
3298 printing characters. */
3300 if (set_id) set_id = string_printing(set_id);
3302 /* For the non-OK cases, set up additional logging data if set_id
3306 set_id = set_id && *set_id
3307 ? string_sprintf(" (set_id=%s)", set_id) : US"";
3309 /* Switch on the result */
3314 if (!au->set_id || set_id) /* Complete success */
3316 if (set_id) authenticated_id = string_copy_malloc(set_id);
3317 sender_host_authenticated = au->name;
3318 authentication_failed = FALSE;
3319 authenticated_fail_id = NULL; /* Impossible to already be set? */
3322 (sender_host_address ? protocols : protocols_local)
3323 [pextend + pauthed + (tls_in.active >= 0 ? pcrpted:0)];
3324 *s = *ss = US"235 Authentication succeeded";
3325 authenticated_by = au;
3329 /* Authentication succeeded, but we failed to expand the set_id string.
3330 Treat this as a temporary error. */
3332 auth_defer_msg = expand_string_message;
3336 if (set_id) authenticated_fail_id = string_copy_malloc(set_id);
3337 *s = string_sprintf("435 Unable to authenticate at present%s",
3338 auth_defer_user_msg);
3339 *ss = string_sprintf("435 Unable to authenticate at present%s: %s",
3340 set_id, auth_defer_msg);
3344 *s = *ss = US"501 Invalid base64 data";
3348 *s = *ss = US"501 Authentication cancelled";
3352 *s = *ss = US"553 Initial data not expected";
3356 if (set_id) authenticated_fail_id = string_copy_malloc(set_id);
3357 *s = US"535 Incorrect authentication data";
3358 *ss = string_sprintf("535 Incorrect authentication data%s", set_id);
3362 if (set_id) authenticated_fail_id = string_copy_malloc(set_id);
3363 *s = US"435 Internal error";
3364 *ss = string_sprintf("435 Internal error%s: return %d from authentication "
3365 "check", set_id, rc);
3377 qualify_recipient(uschar ** recipient, uschar * smtp_cmd_data, uschar * tag)
3380 if (allow_unqualified_recipient || strcmpic(*recipient, US"postmaster") == 0)
3382 DEBUG(D_receive) debug_printf("unqualified address %s accepted\n",
3384 rd = Ustrlen(recipient) + 1;
3385 *recipient = rewrite_address_qualify(*recipient, TRUE);
3388 smtp_printf("501 %s: recipient address must contain a domain\r\n",
3390 log_write(L_smtp_syntax_error,
3391 LOG_MAIN|LOG_REJECT, "unqualified %s rejected: <%s> %s%s",
3392 tag, *recipient, host_and_ident(TRUE), host_lookup_msg);
3400 smtp_quit_handler(uschar ** user_msgp, uschar ** log_msgp)
3403 incomplete_transaction_log(US"QUIT");
3406 int rc = acl_check(ACL_WHERE_QUIT, NULL, acl_smtp_quit, user_msgp, log_msgp);
3408 log_write(0, LOG_MAIN|LOG_PANIC, "ACL for QUIT returned ERROR: %s",
3412 smtp_respond(US"221", 3, TRUE, *user_msgp);
3414 smtp_printf("221 %s closing connection\r\n", smtp_active_hostname);
3417 tls_close(TRUE, TRUE);
3420 log_write(L_smtp_connection, LOG_MAIN, "%s closed by QUIT",
3421 smtp_get_connection_info());
3426 smtp_rset_handler(void)
3429 incomplete_transaction_log(US"RSET");
3430 smtp_printf("250 Reset OK\r\n");
3431 cmd_list[CMD_LIST_RSET].is_mail_cmd = FALSE;
3436 /*************************************************
3437 * Initialize for SMTP incoming message *
3438 *************************************************/
3440 /* This function conducts the initial dialogue at the start of an incoming SMTP
3441 message, and builds a list of recipients. However, if the incoming message
3442 is part of a batch (-bS option) a separate function is called since it would
3443 be messy having tests splattered about all over this function. This function
3444 therefore handles the case where interaction is occurring. The input and output
3445 files are set up in smtp_in and smtp_out.
3447 The global recipients_list is set to point to a vector of recipient_item
3448 blocks, whose number is given by recipients_count. This is extended by the
3449 receive_add_recipient() function. The global variable sender_address is set to
3450 the sender's address. The yield is +1 if a message has been successfully
3451 started, 0 if a QUIT command was encountered or the connection was refused from
3452 the particular host, or -1 if the connection was lost.
3456 Returns: > 0 message successfully started (reached DATA)
3457 = 0 QUIT read or end of file reached or call refused
3462 smtp_setup_msg(void)
3465 BOOL toomany = FALSE;
3466 BOOL discarded = FALSE;
3467 BOOL last_was_rej_mail = FALSE;
3468 BOOL last_was_rcpt = FALSE;
3469 void *reset_point = store_get(0);
3471 DEBUG(D_receive) debug_printf("smtp_setup_msg entered\n");
3473 /* Reset for start of new message. We allow one RSET not to be counted as a
3474 nonmail command, for those MTAs that insist on sending it between every
3475 message. Ditto for EHLO/HELO and for STARTTLS, to allow for going in and out of
3476 TLS between messages (an Exim client may do this if it has messages queued up
3477 for the host). Note: we do NOT reset AUTH at this point. */
3479 smtp_reset(reset_point);
3480 message_ended = END_NOTSTARTED;
3482 chunking_state = chunking_offered ? CHUNKING_OFFERED : CHUNKING_NOT_OFFERED;
3484 cmd_list[CMD_LIST_RSET].is_mail_cmd = TRUE;
3485 cmd_list[CMD_LIST_HELO].is_mail_cmd = TRUE;
3486 cmd_list[CMD_LIST_EHLO].is_mail_cmd = TRUE;
3488 cmd_list[CMD_LIST_STARTTLS].is_mail_cmd = TRUE;
3489 cmd_list[CMD_LIST_TLS_AUTH].is_mail_cmd = TRUE;
3492 /* Set the local signal handler for SIGTERM - it tries to end off tidily */
3494 os_non_restarting_signal(SIGTERM, command_sigterm_handler);
3496 /* Batched SMTP is handled in a different function. */
3498 if (smtp_batched_input) return smtp_setup_batch_msg();
3500 /* Deal with SMTP commands. This loop is exited by setting done to a POSITIVE
3501 value. The values are 2 larger than the required yield of the function. */
3505 const uschar **argv;
3506 uschar *etrn_command;
3507 uschar *etrn_serialize_key;
3509 uschar *log_msg, *smtp_code;
3510 uschar *user_msg = NULL;
3511 uschar *recipient = NULL;
3512 uschar *hello = NULL;
3514 BOOL was_rej_mail = FALSE;
3515 BOOL was_rcpt = FALSE;
3516 void (*oldsignal)(int);
3518 int start, end, sender_domain, recipient_domain;
3522 uschar *orcpt = NULL;
3525 #if defined(SUPPORT_TLS) && defined(AUTH_TLS)
3526 /* Check once per STARTTLS or SSL-on-connect for a TLS AUTH */
3527 if ( tls_in.active >= 0
3529 && tls_in.certificate_verified
3530 && cmd_list[CMD_LIST_TLS_AUTH].is_mail_cmd
3533 cmd_list[CMD_LIST_TLS_AUTH].is_mail_cmd = FALSE;
3535 && (rc = acl_check(ACL_WHERE_AUTH, NULL, acl_smtp_auth,
3536 &user_msg, &log_msg)) != OK
3539 done = smtp_handle_acl_fail(ACL_WHERE_AUTH, rc, user_msg, log_msg);
3543 for (au = auths; au; au = au->next)
3544 if (strcmpic(US"tls", au->driver_name) == 0)
3546 smtp_cmd_data = NULL;
3548 if (smtp_in_auth(au, &s, &ss) == OK)
3549 { DEBUG(D_auth) debug_printf("tls auth succeeded\n"); }
3551 { DEBUG(D_auth) debug_printf("tls auth not succeeded\n"); }
3557 switch(smtp_read_command(TRUE))
3559 /* The AUTH command is not permitted to occur inside a transaction, and may
3560 occur successfully only once per connection. Actually, that isn't quite
3561 true. When TLS is started, all previous information about a connection must
3562 be discarded, so a new AUTH is permitted at that time.
3564 AUTH may only be used when it has been advertised. However, it seems that
3565 there are clients that send AUTH when it hasn't been advertised, some of
3566 them even doing this after HELO. And there are MTAs that accept this. Sigh.
3567 So there's a get-out that allows this to happen.
3569 AUTH is initially labelled as a "nonmail command" so that one occurrence
3570 doesn't get counted. We change the label here so that multiple failing
3571 AUTHS will eventually hit the nonmail threshold. */
3575 authentication_failed = TRUE;
3576 cmd_list[CMD_LIST_AUTH].is_mail_cmd = FALSE;
3578 if (!auth_advertised && !allow_auth_unadvertised)
3580 done = synprot_error(L_smtp_protocol_error, 503, NULL,
3581 US"AUTH command used when not advertised");
3584 if (sender_host_authenticated)
3586 done = synprot_error(L_smtp_protocol_error, 503, NULL,
3587 US"already authenticated");
3592 done = synprot_error(L_smtp_protocol_error, 503, NULL,
3593 US"not permitted in mail transaction");
3600 && (rc = acl_check(ACL_WHERE_AUTH, NULL, acl_smtp_auth,
3601 &user_msg, &log_msg)) != OK
3604 done = smtp_handle_acl_fail(ACL_WHERE_AUTH, rc, user_msg, log_msg);
3608 /* Find the name of the requested authentication mechanism. */
3611 while ((c = *smtp_cmd_data) != 0 && !isspace(c))
3613 if (!isalnum(c) && c != '-' && c != '_')
3615 done = synprot_error(L_smtp_syntax_error, 501, NULL,
3616 US"invalid character in authentication mechanism name");
3622 /* If not at the end of the line, we must be at white space. Terminate the
3623 name and move the pointer on to any data that may be present. */
3625 if (*smtp_cmd_data != 0)
3627 *smtp_cmd_data++ = 0;
3628 while (isspace(*smtp_cmd_data)) smtp_cmd_data++;
3631 /* Search for an authentication mechanism which is configured for use
3632 as a server and which has been advertised (unless, sigh, allow_auth_
3633 unadvertised is set). */
3635 for (au = auths; au; au = au->next)
3636 if (strcmpic(s, au->public_name) == 0 && au->server &&
3637 (au->advertised || allow_auth_unadvertised))
3642 c = smtp_in_auth(au, &s, &ss);
3644 smtp_printf("%s\r\n", s);
3646 log_write(0, LOG_MAIN|LOG_REJECT, "%s authenticator failed for %s: %s",
3647 au->name, host_and_ident(FALSE), ss);
3650 done = synprot_error(L_smtp_protocol_error, 504, NULL,
3651 string_sprintf("%s authentication mechanism not supported", s));
3653 break; /* AUTH_CMD */
3655 /* The HELO/EHLO commands are permitted to appear in the middle of a
3656 session as well as at the beginning. They have the effect of a reset in
3657 addition to their other functions. Their absence at the start cannot be
3658 taken to be an error.
3662 If the EHLO command is not acceptable to the SMTP server, 501, 500,
3663 or 502 failure replies MUST be returned as appropriate. The SMTP
3664 server MUST stay in the same state after transmitting these replies
3665 that it was in before the EHLO was received.
3667 Therefore, we do not do the reset until after checking the command for
3668 acceptability. This change was made for Exim release 4.11. Previously
3669 it did the reset first. */
3682 HELO_EHLO: /* Common code for HELO and EHLO */
3683 cmd_list[CMD_LIST_HELO].is_mail_cmd = FALSE;
3684 cmd_list[CMD_LIST_EHLO].is_mail_cmd = FALSE;
3686 /* Reject the HELO if its argument was invalid or non-existent. A
3687 successful check causes the argument to be saved in malloc store. */
3689 if (!check_helo(smtp_cmd_data))
3691 smtp_printf("501 Syntactically invalid %s argument(s)\r\n", hello);
3693 log_write(0, LOG_MAIN|LOG_REJECT, "rejected %s from %s: syntactically "
3694 "invalid argument(s): %s", hello, host_and_ident(FALSE),
3695 (*smtp_cmd_argument == 0)? US"(no argument given)" :
3696 string_printing(smtp_cmd_argument));
3698 if (++synprot_error_count > smtp_max_synprot_errors)
3700 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
3701 "syntax or protocol errors (last command was \"%s\")",
3702 host_and_ident(FALSE), string_printing(smtp_cmd_buffer));
3709 /* If sender_host_unknown is true, we have got here via the -bs interface,
3710 not called from inetd. Otherwise, we are running an IP connection and the
3711 host address will be set. If the helo name is the primary name of this
3712 host and we haven't done a reverse lookup, force one now. If helo_required
3713 is set, ensure that the HELO name matches the actual host. If helo_verify
3714 is set, do the same check, but softly. */
3716 if (!sender_host_unknown)
3718 BOOL old_helo_verified = helo_verified;
3719 uschar *p = smtp_cmd_data;
3721 while (*p != 0 && !isspace(*p)) { *p = tolower(*p); p++; }
3724 /* Force a reverse lookup if HELO quoted something in helo_lookup_domains
3725 because otherwise the log can be confusing. */
3727 if (sender_host_name == NULL &&
3728 (deliver_domain = sender_helo_name, /* set $domain */
3729 match_isinlist(sender_helo_name, CUSS &helo_lookup_domains, 0,
3730 &domainlist_anchor, NULL, MCL_DOMAIN, TRUE, NULL)) == OK)
3731 (void)host_name_lookup();
3733 /* Rebuild the fullhost info to include the HELO name (and the real name
3734 if it was looked up.) */
3736 host_build_sender_fullhost(); /* Rebuild */
3737 set_process_info("handling%s incoming connection from %s",
3738 (tls_in.active >= 0)? " TLS" : "", host_and_ident(FALSE));
3740 /* Verify if configured. This doesn't give much security, but it does
3741 make some people happy to be able to do it. If helo_required is set,
3742 (host matches helo_verify_hosts) failure forces rejection. If helo_verify
3743 is set (host matches helo_try_verify_hosts), it does not. This is perhaps
3744 now obsolescent, since the verification can now be requested selectively
3747 helo_verified = helo_verify_failed = sender_helo_dnssec = FALSE;
3748 if (helo_required || helo_verify)
3750 BOOL tempfail = !smtp_verify_helo();
3755 smtp_printf("%d %s argument does not match calling host\r\n",
3756 tempfail? 451 : 550, hello);
3757 log_write(0, LOG_MAIN|LOG_REJECT, "%srejected \"%s %s\" from %s",
3758 tempfail? "temporarily " : "",
3759 hello, sender_helo_name, host_and_ident(FALSE));
3760 helo_verified = old_helo_verified;
3761 break; /* End of HELO/EHLO processing */
3763 HDEBUG(D_all) debug_printf("%s verification failed but host is in "
3764 "helo_try_verify_hosts\n", hello);
3769 #ifdef EXPERIMENTAL_SPF
3770 /* set up SPF context */
3771 spf_init(sender_helo_name, sender_host_address);
3774 /* Apply an ACL check if one is defined; afterwards, recheck
3775 synchronization in case the client started sending in a delay. */
3778 if ((rc = acl_check(ACL_WHERE_HELO, NULL, acl_smtp_helo,
3779 &user_msg, &log_msg)) != OK)
3781 done = smtp_handle_acl_fail(ACL_WHERE_HELO, rc, user_msg, log_msg);
3782 sender_helo_name = NULL;
3783 host_build_sender_fullhost(); /* Rebuild */
3786 else if (!check_sync()) goto SYNC_FAILURE;
3788 /* Generate an OK reply. The default string includes the ident if present,
3789 and also the IP address if present. Reflecting back the ident is intended
3790 as a deterrent to mail forgers. For maximum efficiency, and also because
3791 some broken systems expect each response to be in a single packet, arrange
3792 that the entire reply is sent in one write(). */
3794 auth_advertised = FALSE;
3795 pipelining_advertised = FALSE;
3797 tls_advertised = FALSE;
3799 dsn_advertised = FALSE;
3801 smtputf8_advertised = FALSE;
3804 smtp_code = US"250 "; /* Default response code plus space*/
3805 if (user_msg == NULL)
3807 s = string_sprintf("%.3s %s Hello %s%s%s",
3809 smtp_active_hostname,
3810 (sender_ident == NULL)? US"" : sender_ident,
3811 (sender_ident == NULL)? US"" : US" at ",
3812 (sender_host_name == NULL)? sender_helo_name : sender_host_name);
3817 if (sender_host_address != NULL)
3819 s = string_catn(s, &size, &ptr, US" [", 2);
3820 s = string_cat (s, &size, &ptr, sender_host_address);
3821 s = string_catn(s, &size, &ptr, US"]", 1);
3825 /* A user-supplied EHLO greeting may not contain more than one line. Note
3826 that the code returned by smtp_message_code() includes the terminating
3827 whitespace character. */
3833 smtp_message_code(&smtp_code, &codelen, &user_msg, NULL, TRUE);
3834 s = string_sprintf("%.*s%s", codelen, smtp_code, user_msg);
3835 if ((ss = strpbrk(CS s, "\r\n")) != NULL)
3837 log_write(0, LOG_MAIN|LOG_PANIC, "EHLO/HELO response must not contain "
3838 "newlines: message truncated: %s", string_printing(s));
3845 s = string_catn(s, &size, &ptr, US"\r\n", 2);
3847 /* If we received EHLO, we must create a multiline response which includes
3848 the functions supported. */
3854 /* I'm not entirely happy with this, as an MTA is supposed to check
3855 that it has enough room to accept a message of maximum size before
3856 it sends this. However, there seems little point in not sending it.
3857 The actual size check happens later at MAIL FROM time. By postponing it
3858 till then, VRFY and EXPN can be used after EHLO when space is short. */
3860 if (thismessage_size_limit > 0)
3862 sprintf(CS big_buffer, "%.3s-SIZE %d\r\n", smtp_code,
3863 thismessage_size_limit);
3864 s = string_cat(s, &size, &ptr, big_buffer);
3868 s = string_catn(s, &size, &ptr, smtp_code, 3);
3869 s = string_catn(s, &size, &ptr, US"-SIZE\r\n", 7);
3872 /* Exim does not do protocol conversion or data conversion. It is 8-bit
3873 clean; if it has an 8-bit character in its hand, it just sends it. It
3874 cannot therefore specify 8BITMIME and remain consistent with the RFCs.
3875 However, some users want this option simply in order to stop MUAs
3876 mangling messages that contain top-bit-set characters. It is therefore
3877 provided as an option. */
3879 if (accept_8bitmime)
3881 s = string_catn(s, &size, &ptr, smtp_code, 3);
3882 s = string_catn(s, &size, &ptr, US"-8BITMIME\r\n", 11);
3885 /* Advertise DSN support if configured to do so. */
3886 if (verify_check_host(&dsn_advertise_hosts) != FAIL)
3888 s = string_catn(s, &size, &ptr, smtp_code, 3);
3889 s = string_catn(s, &size, &ptr, US"-DSN\r\n", 6);
3890 dsn_advertised = TRUE;
3893 /* Advertise ETRN if there's an ACL checking whether a host is
3894 permitted to issue it; a check is made when any host actually tries. */
3896 if (acl_smtp_etrn != NULL)
3898 s = string_catn(s, &size, &ptr, smtp_code, 3);
3899 s = string_catn(s, &size, &ptr, US"-ETRN\r\n", 7);
3902 /* Advertise EXPN if there's an ACL checking whether a host is
3903 permitted to issue it; a check is made when any host actually tries. */
3905 if (acl_smtp_expn != NULL)
3907 s = string_catn(s, &size, &ptr, smtp_code, 3);
3908 s = string_catn(s, &size, &ptr, US"-EXPN\r\n", 7);
3911 /* Exim is quite happy with pipelining, so let the other end know that
3912 it is safe to use it, unless advertising is disabled. */
3914 if (pipelining_enable &&
3915 verify_check_host(&pipelining_advertise_hosts) == OK)
3917 s = string_catn(s, &size, &ptr, smtp_code, 3);
3918 s = string_catn(s, &size, &ptr, US"-PIPELINING\r\n", 13);
3919 sync_cmd_limit = NON_SYNC_CMD_PIPELINING;
3920 pipelining_advertised = TRUE;
3924 /* If any server authentication mechanisms are configured, advertise
3925 them if the current host is in auth_advertise_hosts. The problem with
3926 advertising always is that some clients then require users to
3927 authenticate (and aren't configurable otherwise) even though it may not
3928 be necessary (e.g. if the host is in host_accept_relay).
3930 RFC 2222 states that SASL mechanism names contain only upper case
3931 letters, so output the names in upper case, though we actually recognize
3932 them in either case in the AUTH command. */
3935 #if defined(SUPPORT_TLS) && defined(AUTH_TLS)
3936 && !sender_host_authenticated
3938 && verify_check_host(&auth_advertise_hosts) == OK
3943 for (au = auths; au; au = au->next)
3944 if (au->server && (au->advertise_condition == NULL ||
3945 expand_check_condition(au->advertise_condition, au->name,
3946 US"authenticator")))
3951 s = string_catn(s, &size, &ptr, smtp_code, 3);
3952 s = string_catn(s, &size, &ptr, US"-AUTH", 5);
3954 auth_advertised = TRUE;
3957 s = string_catn(s, &size, &ptr, US" ", 1);
3958 s = string_cat (s, &size, &ptr, au->public_name);
3959 while (++saveptr < ptr) s[saveptr] = toupper(s[saveptr]);
3960 au->advertised = TRUE;
3963 au->advertised = FALSE;
3965 if (!first) s = string_catn(s, &size, &ptr, US"\r\n", 2);
3968 /* RFC 3030 CHUNKING */
3970 if (verify_check_host(&chunking_advertise_hosts) != FAIL)
3972 s = string_catn(s, &size, &ptr, smtp_code, 3);
3973 s = string_catn(s, &size, &ptr, US"-CHUNKING\r\n", 11);
3974 chunking_offered = TRUE;
3975 chunking_state = CHUNKING_OFFERED;
3978 /* Advertise TLS (Transport Level Security) aka SSL (Secure Socket Layer)
3979 if it has been included in the binary, and the host matches
3980 tls_advertise_hosts. We must *not* advertise if we are already in a
3981 secure connection. */
3984 if (tls_in.active < 0 &&
3985 verify_check_host(&tls_advertise_hosts) != FAIL)
3987 s = string_catn(s, &size, &ptr, smtp_code, 3);
3988 s = string_catn(s, &size, &ptr, US"-STARTTLS\r\n", 11);
3989 tls_advertised = TRUE;
3993 #ifndef DISABLE_PRDR
3994 /* Per Recipient Data Response, draft by Eric A. Hall extending RFC */
3997 s = string_catn(s, &size, &ptr, smtp_code, 3);
3998 s = string_catn(s, &size, &ptr, US"-PRDR\r\n", 7);
4003 if ( accept_8bitmime
4004 && verify_check_host(&smtputf8_advertise_hosts) != FAIL)
4006 s = string_catn(s, &size, &ptr, smtp_code, 3);
4007 s = string_catn(s, &size, &ptr, US"-SMTPUTF8\r\n", 11);
4008 smtputf8_advertised = TRUE;
4012 /* Finish off the multiline reply with one that is always available. */
4014 s = string_catn(s, &size, &ptr, smtp_code, 3);
4015 s = string_catn(s, &size, &ptr, US" HELP\r\n", 7);
4018 /* Terminate the string (for debug), write it, and note that HELO/EHLO
4024 if (tls_in.active >= 0) (void)tls_write(TRUE, s, ptr); else
4028 int i = fwrite(s, 1, ptr, smtp_out); i = i; /* compiler quietening */
4033 while ((cr = Ustrchr(s, '\r')) != NULL) /* lose CRs */
4034 memmove(cr, cr + 1, (ptr--) - (cr - s));
4035 debug_printf("SMTP>> %s", s);
4039 /* Reset the protocol and the state, abandoning any previous message. */
4041 (sender_host_address ? protocols : protocols_local)
4043 ? pextend + (sender_host_authenticated ? pauthed : 0)
4045 + (tls_in.active >= 0 ? pcrpted : 0)
4047 smtp_reset(reset_point);
4049 break; /* HELO/EHLO */
4052 /* The MAIL command requires an address as an operand. All we do
4053 here is to parse it for syntactic correctness. The form "<>" is
4054 a special case which converts into an empty string. The start/end
4055 pointers in the original are not used further for this address, as
4056 it is the canonical extracted address which is all that is kept. */
4060 smtp_mailcmd_count++; /* Count for limit and ratelimit */
4061 was_rej_mail = TRUE; /* Reset if accepted */
4062 env_mail_type_t * mail_args; /* Sanity check & validate args */
4064 if (helo_required && !helo_seen)
4066 smtp_printf("503 HELO or EHLO required\r\n");
4067 log_write(0, LOG_MAIN|LOG_REJECT, "rejected MAIL from %s: no "
4068 "HELO/EHLO given", host_and_ident(FALSE));
4072 if (sender_address != NULL)
4074 done = synprot_error(L_smtp_protocol_error, 503, NULL,
4075 US"sender already given");
4079 if (smtp_cmd_data[0] == 0)
4081 done = synprot_error(L_smtp_protocol_error, 501, NULL,
4082 US"MAIL must have an address operand");
4086 /* Check to see if the limit for messages per connection would be
4087 exceeded by accepting further messages. */
4089 if (smtp_accept_max_per_connection > 0 &&
4090 smtp_mailcmd_count > smtp_accept_max_per_connection)
4092 smtp_printf("421 too many messages in this connection\r\n");
4093 log_write(0, LOG_MAIN|LOG_REJECT, "rejected MAIL command %s: too many "
4094 "messages in one connection", host_and_ident(TRUE));
4098 /* Reset for start of message - even if this is going to fail, we
4099 obviously need to throw away any previous data. */
4101 smtp_reset(reset_point);
4103 sender_data = recipient_data = NULL;
4105 /* Loop, checking for ESMTP additions to the MAIL FROM command. */
4109 uschar *name, *value, *end;
4110 unsigned long int size;
4111 BOOL arg_error = FALSE;
4113 if (!extract_option(&name, &value)) break;
4115 for (mail_args = env_mail_type_list;
4116 mail_args->value != ENV_MAIL_OPT_NULL;
4119 if (strcmpic(name, mail_args->name) == 0)
4121 if (mail_args->need_value && strcmpic(value, US"") == 0)
4124 switch(mail_args->value)
4126 /* Handle SIZE= by reading the value. We don't do the check till later,
4127 in order to be able to log the sender address on failure. */
4128 case ENV_MAIL_OPT_SIZE:
4129 if (((size = Ustrtoul(value, &end, 10)), *end == 0))
4131 if ((size == ULONG_MAX && errno == ERANGE) || size > INT_MAX)
4133 message_size = (int)size;
4139 /* If this session was initiated with EHLO and accept_8bitmime is set,
4140 Exim will have indicated that it supports the BODY=8BITMIME option. In
4141 fact, it does not support this according to the RFCs, in that it does not
4142 take any special action for forwarding messages containing 8-bit
4143 characters. That is why accept_8bitmime is not the default setting, but
4144 some sites want the action that is provided. We recognize both "8BITMIME"
4145 and "7BIT" as body types, but take no action. */
4146 case ENV_MAIL_OPT_BODY:
4147 if (accept_8bitmime) {
4148 if (strcmpic(value, US"8BITMIME") == 0)
4150 else if (strcmpic(value, US"7BIT") == 0)
4155 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4156 US"invalid data for BODY");
4159 DEBUG(D_receive) debug_printf("8BITMIME: %d\n", body_8bitmime);
4165 /* Handle the two DSN options, but only if configured to do so (which
4166 will have caused "DSN" to be given in the EHLO response). The code itself
4167 is included only if configured in at build time. */
4169 case ENV_MAIL_OPT_RET:
4172 /* Check if RET has already been set */
4175 synprot_error(L_smtp_syntax_error, 501, NULL,
4176 US"RET can be specified once only");
4179 dsn_ret = strcmpic(value, US"HDRS") == 0
4181 : strcmpic(value, US"FULL") == 0
4184 DEBUG(D_receive) debug_printf("DSN_RET: %d\n", dsn_ret);
4185 /* Check for invalid invalid value, and exit with error */
4188 synprot_error(L_smtp_syntax_error, 501, NULL,
4189 US"Value for RET is invalid");
4194 case ENV_MAIL_OPT_ENVID:
4197 /* Check if the dsn envid has been already set */
4198 if (dsn_envid != NULL)
4200 synprot_error(L_smtp_syntax_error, 501, NULL,
4201 US"ENVID can be specified once only");
4204 dsn_envid = string_copy(value);
4205 DEBUG(D_receive) debug_printf("DSN_ENVID: %s\n", dsn_envid);
4209 /* Handle the AUTH extension. If the value given is not "<>" and either
4210 the ACL says "yes" or there is no ACL but the sending host is
4211 authenticated, we set it up as the authenticated sender. However, if the
4212 authenticator set a condition to be tested, we ignore AUTH on MAIL unless
4213 the condition is met. The value of AUTH is an xtext, which means that +,
4214 = and cntrl chars are coded in hex; however "<>" is unaffected by this
4216 case ENV_MAIL_OPT_AUTH:
4217 if (Ustrcmp(value, "<>") != 0)
4222 if (auth_xtextdecode(value, &authenticated_sender) < 0)
4224 /* Put back terminator overrides for error message */
4227 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4228 US"invalid data for AUTH");
4231 if (acl_smtp_mailauth == NULL)
4233 ignore_msg = US"client not authenticated";
4234 rc = (sender_host_authenticated != NULL)? OK : FAIL;
4238 ignore_msg = US"rejected by ACL";
4239 rc = acl_check(ACL_WHERE_MAILAUTH, NULL, acl_smtp_mailauth,
4240 &user_msg, &log_msg);
4246 if (authenticated_by == NULL ||
4247 authenticated_by->mail_auth_condition == NULL ||
4248 expand_check_condition(authenticated_by->mail_auth_condition,
4249 authenticated_by->name, US"authenticator"))
4250 break; /* Accept the AUTH */
4252 ignore_msg = US"server_mail_auth_condition failed";
4253 if (authenticated_id != NULL)
4254 ignore_msg = string_sprintf("%s: authenticated ID=\"%s\"",
4255 ignore_msg, authenticated_id);
4260 authenticated_sender = NULL;
4261 log_write(0, LOG_MAIN, "ignoring AUTH=%s from %s (%s)",
4262 value, host_and_ident(TRUE), ignore_msg);
4265 /* Should only get DEFER or ERROR here. Put back terminator
4266 overrides for error message */
4271 (void)smtp_handle_acl_fail(ACL_WHERE_MAILAUTH, rc, user_msg,
4278 #ifndef DISABLE_PRDR
4279 case ENV_MAIL_OPT_PRDR:
4281 prdr_requested = TRUE;
4286 case ENV_MAIL_OPT_UTF8:
4287 if (smtputf8_advertised)
4289 DEBUG(D_receive) debug_printf("smtputf8 requested\n");
4290 message_smtputf8 = allow_utf8_domains = TRUE;
4291 received_protocol = string_sprintf("utf8%s", received_protocol);
4295 /* No valid option. Stick back the terminator characters and break
4296 the loop. Do the name-terminator second as extract_option sets
4297 value==name when it found no equal-sign.
4298 An error for a malformed address will occur. */
4299 case ENV_MAIL_OPT_NULL:
4307 /* Break out of for loop if switch() had bad argument or
4308 when start of the email address is reached */
4309 if (arg_error) break;
4312 /* If we have passed the threshold for rate limiting, apply the current
4313 delay, and update it for next time, provided this is a limited host. */
4315 if (smtp_mailcmd_count > smtp_rlm_threshold &&
4316 verify_check_host(&smtp_ratelimit_hosts) == OK)
4318 DEBUG(D_receive) debug_printf("rate limit MAIL: delay %.3g sec\n",
4319 smtp_delay_mail/1000.0);
4320 millisleep((int)smtp_delay_mail);
4321 smtp_delay_mail *= smtp_rlm_factor;
4322 if (smtp_delay_mail > (double)smtp_rlm_limit)
4323 smtp_delay_mail = (double)smtp_rlm_limit;
4326 /* Now extract the address, first applying any SMTP-time rewriting. The
4327 TRUE flag allows "<>" as a sender address. */
4329 raw_sender = rewrite_existflags & rewrite_smtp
4330 ? rewrite_one(smtp_cmd_data, rewrite_smtp, NULL, FALSE, US"",
4331 global_rewrite_rules)
4335 parse_extract_address(raw_sender, &errmess, &start, &end, &sender_domain,
4340 done = synprot_error(L_smtp_syntax_error, 501, smtp_cmd_data, errmess);
4344 sender_address = raw_sender;
4346 /* If there is a configured size limit for mail, check that this message
4347 doesn't exceed it. The check is postponed to this point so that the sender
4350 if (thismessage_size_limit > 0 && message_size > thismessage_size_limit)
4352 smtp_printf("552 Message size exceeds maximum permitted\r\n");
4353 log_write(L_size_reject,
4354 LOG_MAIN|LOG_REJECT, "rejected MAIL FROM:<%s> %s: "
4355 "message too big: size%s=%d max=%d",
4357 host_and_ident(TRUE),
4358 (message_size == INT_MAX)? ">" : "",
4360 thismessage_size_limit);
4361 sender_address = NULL;
4365 /* Check there is enough space on the disk unless configured not to.
4366 When smtp_check_spool_space is set, the check is for thismessage_size_limit
4367 plus the current message - i.e. we accept the message only if it won't
4368 reduce the space below the threshold. Add 5000 to the size to allow for
4369 overheads such as the Received: line and storing of recipients, etc.
4370 By putting the check here, even when SIZE is not given, it allow VRFY
4371 and EXPN etc. to be used when space is short. */
4373 if (!receive_check_fs(
4374 (smtp_check_spool_space && message_size >= 0)?
4375 message_size + 5000 : 0))
4377 smtp_printf("452 Space shortage, please try later\r\n");
4378 sender_address = NULL;
4382 /* If sender_address is unqualified, reject it, unless this is a locally
4383 generated message, or the sending host or net is permitted to send
4384 unqualified addresses - typically local machines behaving as MUAs -
4385 in which case just qualify the address. The flag is set above at the start
4386 of the SMTP connection. */
4388 if (sender_domain == 0 && sender_address[0] != 0)
4390 if (allow_unqualified_sender)
4392 sender_domain = Ustrlen(sender_address) + 1;
4393 sender_address = rewrite_address_qualify(sender_address, FALSE);
4394 DEBUG(D_receive) debug_printf("unqualified address %s accepted\n",
4399 smtp_printf("501 %s: sender address must contain a domain\r\n",
4401 log_write(L_smtp_syntax_error,
4402 LOG_MAIN|LOG_REJECT,
4403 "unqualified sender rejected: <%s> %s%s",
4405 host_and_ident(TRUE),
4407 sender_address = NULL;
4412 /* Apply an ACL check if one is defined, before responding. Afterwards,
4413 when pipelining is not advertised, do another sync check in case the ACL
4414 delayed and the client started sending in the meantime. */
4418 rc = acl_check(ACL_WHERE_MAIL, NULL, acl_smtp_mail, &user_msg, &log_msg);
4419 if (rc == OK && !pipelining_advertised && !check_sync())
4425 if (rc == OK || rc == DISCARD)
4428 smtp_printf("%s%s%s", US"250 OK",
4429 #ifndef DISABLE_PRDR
4430 prdr_requested ? US", PRDR Requested" : US"",
4437 #ifndef DISABLE_PRDR
4439 user_msg = string_sprintf("%s%s", user_msg, US", PRDR Requested");
4441 smtp_user_msg(US"250", user_msg);
4443 smtp_delay_rcpt = smtp_rlr_base;
4444 recipients_discarded = (rc == DISCARD);
4445 was_rej_mail = FALSE;
4449 done = smtp_handle_acl_fail(ACL_WHERE_MAIL, rc, user_msg, log_msg);
4450 sender_address = NULL;
4455 /* The RCPT command requires an address as an operand. There may be any
4456 number of RCPT commands, specifying multiple recipients. We build them all
4457 into a data structure. The start/end values given by parse_extract_address
4458 are not used, as we keep only the extracted address. */
4463 was_rcpt = rcpt_in_progress = TRUE;
4465 /* There must be a sender address; if the sender was rejected and
4466 pipelining was advertised, we assume the client was pipelining, and do not
4467 count this as a protocol error. Reset was_rej_mail so that further RCPTs
4468 get the same treatment. */
4470 if (sender_address == NULL)
4472 if (pipelining_advertised && last_was_rej_mail)
4474 smtp_printf("503 sender not yet given\r\n");
4475 was_rej_mail = TRUE;
4479 done = synprot_error(L_smtp_protocol_error, 503, NULL,
4480 US"sender not yet given");
4481 was_rcpt = FALSE; /* Not a valid RCPT */
4487 /* Check for an operand */
4489 if (smtp_cmd_data[0] == 0)
4491 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4492 US"RCPT must have an address operand");
4497 /* Set the DSN flags orcpt and dsn_flags from the session*/
4503 uschar *name, *value;
4505 if (!extract_option(&name, &value))
4508 if (dsn_advertised && strcmpic(name, US"ORCPT") == 0)
4510 /* Check whether orcpt has been already set */
4513 synprot_error(L_smtp_syntax_error, 501, NULL,
4514 US"ORCPT can be specified once only");
4517 orcpt = string_copy(value);
4518 DEBUG(D_receive) debug_printf("DSN orcpt: %s\n", orcpt);
4521 else if (dsn_advertised && strcmpic(name, US"NOTIFY") == 0)
4523 /* Check if the notify flags have been already set */
4526 synprot_error(L_smtp_syntax_error, 501, NULL,
4527 US"NOTIFY can be specified once only");
4530 if (strcmpic(value, US"NEVER") == 0)
4531 flags |= rf_notify_never;
4538 while (*pp != 0 && *pp != ',') pp++;
4539 if (*pp == ',') *pp++ = 0;
4540 if (strcmpic(p, US"SUCCESS") == 0)
4542 DEBUG(D_receive) debug_printf("DSN: Setting notify success\n");
4543 flags |= rf_notify_success;
4545 else if (strcmpic(p, US"FAILURE") == 0)
4547 DEBUG(D_receive) debug_printf("DSN: Setting notify failure\n");
4548 flags |= rf_notify_failure;
4550 else if (strcmpic(p, US"DELAY") == 0)
4552 DEBUG(D_receive) debug_printf("DSN: Setting notify delay\n");
4553 flags |= rf_notify_delay;
4557 /* Catch any strange values */
4558 synprot_error(L_smtp_syntax_error, 501, NULL,
4559 US"Invalid value for NOTIFY parameter");
4564 DEBUG(D_receive) debug_printf("DSN Flags: %x\n", flags);
4568 /* Unknown option. Stick back the terminator characters and break
4569 the loop. An error for a malformed address will occur. */
4573 DEBUG(D_receive) debug_printf("Invalid RCPT option: %s : %s\n", name, value);
4580 /* Apply SMTP rewriting then extract the working address. Don't allow "<>"
4581 as a recipient address */
4583 recipient = rewrite_existflags & rewrite_smtp
4584 ? rewrite_one(smtp_cmd_data, rewrite_smtp, NULL, FALSE, US"",
4585 global_rewrite_rules)
4588 if (!(recipient = parse_extract_address(recipient, &errmess, &start, &end,
4589 &recipient_domain, FALSE)))
4591 done = synprot_error(L_smtp_syntax_error, 501, smtp_cmd_data, errmess);
4596 /* If the recipient address is unqualified, reject it, unless this is a
4597 locally generated message. However, unqualified addresses are permitted
4598 from a configured list of hosts and nets - typically when behaving as
4599 MUAs rather than MTAs. Sad that SMTP is used for both types of traffic,
4600 really. The flag is set at the start of the SMTP connection.
4602 RFC 1123 talks about supporting "the reserved mailbox postmaster"; I always
4603 assumed this meant "reserved local part", but the revision of RFC 821 and
4604 friends now makes it absolutely clear that it means *mailbox*. Consequently
4605 we must always qualify this address, regardless. */
4607 if (recipient_domain == 0)
4608 if (!(recipient_domain = qualify_recipient(&recipient, smtp_cmd_data,
4615 /* Check maximum allowed */
4617 if (rcpt_count > recipients_max && recipients_max > 0)
4619 if (recipients_max_reject)
4622 smtp_printf("552 too many recipients\r\n");
4624 log_write(0, LOG_MAIN|LOG_REJECT, "too many recipients: message "
4625 "rejected: sender=<%s> %s", sender_address, host_and_ident(TRUE));
4630 smtp_printf("452 too many recipients\r\n");
4632 log_write(0, LOG_MAIN|LOG_REJECT, "too many recipients: excess "
4633 "temporarily rejected: sender=<%s> %s", sender_address,
4634 host_and_ident(TRUE));
4641 /* If we have passed the threshold for rate limiting, apply the current
4642 delay, and update it for next time, provided this is a limited host. */
4644 if (rcpt_count > smtp_rlr_threshold &&
4645 verify_check_host(&smtp_ratelimit_hosts) == OK)
4647 DEBUG(D_receive) debug_printf("rate limit RCPT: delay %.3g sec\n",
4648 smtp_delay_rcpt/1000.0);
4649 millisleep((int)smtp_delay_rcpt);
4650 smtp_delay_rcpt *= smtp_rlr_factor;
4651 if (smtp_delay_rcpt > (double)smtp_rlr_limit)
4652 smtp_delay_rcpt = (double)smtp_rlr_limit;
4655 /* If the MAIL ACL discarded all the recipients, we bypass ACL checking
4656 for them. Otherwise, check the access control list for this recipient. As
4657 there may be a delay in this, re-check for a synchronization error
4658 afterwards, unless pipelining was advertised. */
4660 if (recipients_discarded) rc = DISCARD; else
4662 rc = acl_check(ACL_WHERE_RCPT, recipient, acl_smtp_rcpt, &user_msg,
4664 if (rc == OK && !pipelining_advertised && !check_sync())
4668 /* The ACL was happy */
4672 if (user_msg == NULL) smtp_printf("250 Accepted\r\n");
4673 else smtp_user_msg(US"250", user_msg);
4674 receive_add_recipient(recipient, -1);
4676 /* Set the dsn flags in the recipients_list */
4677 recipients_list[recipients_count-1].orcpt = orcpt;
4678 recipients_list[recipients_count-1].dsn_flags = flags;
4680 DEBUG(D_receive) debug_printf("DSN: orcpt: %s flags: %d\n",
4681 recipients_list[recipients_count-1].orcpt,
4682 recipients_list[recipients_count-1].dsn_flags);
4685 /* The recipient was discarded */
4687 else if (rc == DISCARD)
4689 if (user_msg == NULL) smtp_printf("250 Accepted\r\n");
4690 else smtp_user_msg(US"250", user_msg);
4693 log_write(0, LOG_MAIN|LOG_REJECT, "%s F=<%s> RCPT %s: "
4694 "discarded by %s ACL%s%s", host_and_ident(TRUE),
4695 sender_address_unrewritten? sender_address_unrewritten : sender_address,
4696 smtp_cmd_argument, recipients_discarded? "MAIL" : "RCPT",
4697 log_msg ? US": " : US"", log_msg ? log_msg : US"");
4700 /* Either the ACL failed the address, or it was deferred. */
4704 if (rc == FAIL) rcpt_fail_count++; else rcpt_defer_count++;
4705 done = smtp_handle_acl_fail(ACL_WHERE_RCPT, rc, user_msg, log_msg);
4710 /* The DATA command is legal only if it follows successful MAIL FROM
4711 and RCPT TO commands. However, if pipelining is advertised, a bad DATA is
4712 not counted as a protocol error if it follows RCPT (which must have been
4713 rejected if there are no recipients.) This function is complete when a
4714 valid DATA command is encountered.
4716 Note concerning the code used: RFC 2821 says this:
4718 - If there was no MAIL, or no RCPT, command, or all such commands
4719 were rejected, the server MAY return a "command out of sequence"
4720 (503) or "no valid recipients" (554) reply in response to the
4723 The example in the pipelining RFC 2920 uses 554, but I use 503 here
4724 because it is the same whether pipelining is in use or not.
4726 If all the RCPT commands that precede DATA provoked the same error message
4727 (often indicating some kind of system error), it is helpful to include it
4728 with the DATA rejection (an idea suggested by Tony Finch). */
4735 if (chunking_state != CHUNKING_OFFERED)
4737 done = synprot_error(L_smtp_protocol_error, 503, NULL,
4738 US"BDAT command used when CHUNKING not advertised");
4742 /* grab size, endmarker */
4744 if (sscanf(CS smtp_cmd_data, "%u %n", &chunking_datasize, &n) < 1)
4746 done = synprot_error(L_smtp_protocol_error, 501, NULL,
4747 US"missing size for BDAT command");
4750 chunking_state = strcmpic(smtp_cmd_data+n, US"LAST") == 0
4751 ? CHUNKING_LAST : CHUNKING_ACTIVE;
4752 chunking_data_left = chunking_datasize;
4754 lwr_receive_getc = receive_getc;
4755 lwr_receive_ungetc = receive_ungetc;
4756 receive_getc = bdat_getc;
4757 receive_ungetc = bdat_ungetc;
4760 debug_printf("chunking state %d\n", (int)chunking_state);
4767 DATA_BDAT: /* Common code for DATA and BDAT */
4768 if (!discarded && recipients_count <= 0)
4770 if (rcpt_smtp_response_same && rcpt_smtp_response != NULL)
4772 uschar *code = US"503";
4773 int len = Ustrlen(rcpt_smtp_response);
4774 smtp_respond(code, 3, FALSE, US"All RCPT commands were rejected with "
4776 /* Responses from smtp_printf() will have \r\n on the end */
4777 if (len > 2 && rcpt_smtp_response[len-2] == '\r')
4778 rcpt_smtp_response[len-2] = 0;
4779 smtp_respond(code, 3, FALSE, rcpt_smtp_response);
4781 if (pipelining_advertised && last_was_rcpt)
4782 smtp_printf("503 Valid RCPT command must precede %s\r\n",
4783 smtp_names[smtp_connection_had[smtp_ch_index-1]]);
4785 done = synprot_error(L_smtp_protocol_error, 503, NULL,
4786 smtp_connection_had[smtp_ch_index-1] == SCH_DATA
4787 ? US"valid RCPT command must precede DATA"
4788 : US"valid RCPT command must precede BDAT");
4790 if (chunking_state > CHUNKING_OFFERED)
4795 if (toomany && recipients_max_reject)
4797 sender_address = NULL; /* This will allow a new MAIL without RSET */
4798 sender_address_unrewritten = NULL;
4799 smtp_printf("554 Too many recipients\r\n");
4803 if (chunking_state > CHUNKING_OFFERED)
4804 { /* No predata ACL or go-ahead output for BDAT */
4809 /* If there is an ACL, re-check the synchronization afterwards, since the
4810 ACL may have delayed. To handle cutthrough delivery enforce a dummy call
4811 to get the DATA command sent. */
4813 if (acl_smtp_predata == NULL && cutthrough.fd < 0)
4817 uschar * acl = acl_smtp_predata ? acl_smtp_predata : US"accept";
4818 enable_dollar_recipients = TRUE;
4819 rc = acl_check(ACL_WHERE_PREDATA, NULL, acl, &user_msg,
4821 enable_dollar_recipients = FALSE;
4822 if (rc == OK && !check_sync())
4826 { /* Either the ACL failed the address, or it was deferred. */
4827 done = smtp_handle_acl_fail(ACL_WHERE_PREDATA, rc, user_msg, log_msg);
4833 smtp_user_msg(US"354", user_msg);
4836 "354 Enter message, ending with \".\" on a line by itself\r\n");
4840 message_ended = END_NOTENDED; /* Indicate in middle of data */
4851 if (!(address = parse_extract_address(smtp_cmd_data, &errmess,
4852 &start, &end, &recipient_domain, FALSE)))
4854 smtp_printf("501 %s\r\n", errmess);
4858 if (recipient_domain == 0)
4859 if (!(recipient_domain = qualify_recipient(&address, smtp_cmd_data,
4863 if ((rc = acl_check(ACL_WHERE_VRFY, address, acl_smtp_vrfy,
4864 &user_msg, &log_msg)) != OK)
4865 done = smtp_handle_acl_fail(ACL_WHERE_VRFY, rc, user_msg, log_msg);
4869 address_item * addr = deliver_make_addr(address, FALSE);
4871 switch(verify_address(addr, NULL, vopt_is_recipient | vopt_qualify, -1,
4872 -1, -1, NULL, NULL, NULL))
4875 s = string_sprintf("250 <%s> is deliverable", address);
4879 s = (addr->user_message != NULL)?
4880 string_sprintf("451 <%s> %s", address, addr->user_message) :
4881 string_sprintf("451 Cannot resolve <%s> at this time", address);
4885 s = (addr->user_message != NULL)?
4886 string_sprintf("550 <%s> %s", address, addr->user_message) :
4887 string_sprintf("550 <%s> is not deliverable", address);
4888 log_write(0, LOG_MAIN, "VRFY failed for %s %s",
4889 smtp_cmd_argument, host_and_ident(TRUE));
4893 smtp_printf("%s\r\n", s);
4901 rc = acl_check(ACL_WHERE_EXPN, NULL, acl_smtp_expn, &user_msg, &log_msg);
4903 done = smtp_handle_acl_fail(ACL_WHERE_EXPN, rc, user_msg, log_msg);
4906 BOOL save_log_testing_mode = log_testing_mode;
4907 address_test_mode = log_testing_mode = TRUE;
4908 (void) verify_address(deliver_make_addr(smtp_cmd_data, FALSE),
4909 smtp_out, vopt_is_recipient | vopt_qualify | vopt_expn, -1, -1, -1,
4911 address_test_mode = FALSE;
4912 log_testing_mode = save_log_testing_mode; /* true for -bh */
4921 if (!tls_advertised)
4923 done = synprot_error(L_smtp_protocol_error, 503, NULL,
4924 US"STARTTLS command used when not advertised");
4928 /* Apply an ACL check if one is defined */
4930 if ( acl_smtp_starttls
4931 && (rc = acl_check(ACL_WHERE_STARTTLS, NULL, acl_smtp_starttls,
4932 &user_msg, &log_msg)) != OK
4935 done = smtp_handle_acl_fail(ACL_WHERE_STARTTLS, rc, user_msg, log_msg);
4939 /* RFC 2487 is not clear on when this command may be sent, though it
4940 does state that all information previously obtained from the client
4941 must be discarded if a TLS session is started. It seems reasonble to
4942 do an implied RSET when STARTTLS is received. */
4944 incomplete_transaction_log(US"STARTTLS");
4945 smtp_reset(reset_point);
4947 cmd_list[CMD_LIST_STARTTLS].is_mail_cmd = FALSE;
4949 /* There's an attack where more data is read in past the STARTTLS command
4950 before TLS is negotiated, then assumed to be part of the secure session
4951 when used afterwards; we use segregated input buffers, so are not
4952 vulnerable, but we want to note when it happens and, for sheer paranoia,
4953 ensure that the buffer is "wiped".
4954 Pipelining sync checks will normally have protected us too, unless disabled
4955 by configuration. */
4957 if (receive_smtp_buffered())
4960 debug_printf("Non-empty input buffer after STARTTLS; naive attack?\n");
4961 if (tls_in.active < 0)
4962 smtp_inend = smtp_inptr = smtp_inbuffer;
4963 /* and if TLS is already active, tls_server_start() should fail */
4966 /* There is nothing we value in the input buffer and if TLS is succesfully
4967 negotiated, we won't use this buffer again; if TLS fails, we'll just read
4968 fresh content into it. The buffer contains arbitrary content from an
4969 untrusted remote source; eg: NOOP <shellcode>\r\nSTARTTLS\r\n
4970 It seems safest to just wipe away the content rather than leave it as a
4971 target to jump to. */
4973 memset(smtp_inbuffer, 0, in_buffer_size);
4975 /* Attempt to start up a TLS session, and if successful, discard all
4976 knowledge that was obtained previously. At least, that's what the RFC says,
4977 and that's what happens by default. However, in order to work round YAEB,
4978 there is an option to remember the esmtp state. Sigh.
4980 We must allow for an extra EHLO command and an extra AUTH command after
4981 STARTTLS that don't add to the nonmail command count. */
4983 if ((rc = tls_server_start(tls_require_ciphers)) == OK)
4985 if (!tls_remember_esmtp)
4986 helo_seen = esmtp = auth_advertised = pipelining_advertised = FALSE;
4987 cmd_list[CMD_LIST_EHLO].is_mail_cmd = TRUE;
4988 cmd_list[CMD_LIST_AUTH].is_mail_cmd = TRUE;
4989 cmd_list[CMD_LIST_TLS_AUTH].is_mail_cmd = TRUE;
4990 if (sender_helo_name != NULL)
4992 store_free(sender_helo_name);
4993 sender_helo_name = NULL;
4994 host_build_sender_fullhost(); /* Rebuild */
4995 set_process_info("handling incoming TLS connection from %s",
4996 host_and_ident(FALSE));
4999 (sender_host_address ? protocols : protocols_local)
5001 ? pextend + (sender_host_authenticated ? pauthed : 0)
5003 + (tls_in.active >= 0 ? pcrpted : 0)
5006 sender_host_authenticated = NULL;
5007 authenticated_id = NULL;
5008 sync_cmd_limit = NON_SYNC_CMD_NON_PIPELINING;
5009 DEBUG(D_tls) debug_printf("TLS active\n");
5010 break; /* Successful STARTTLS */
5013 /* Some local configuration problem was discovered before actually trying
5014 to do a TLS handshake; give a temporary error. */
5016 else if (rc == DEFER)
5018 smtp_printf("454 TLS currently unavailable\r\n");
5022 /* Hard failure. Reject everything except QUIT or closed connection. One
5023 cause for failure is a nested STARTTLS, in which case tls_in.active remains
5024 set, but we must still reject all incoming commands. */
5026 DEBUG(D_tls) debug_printf("TLS failed to start\n");
5027 while (done <= 0) switch(smtp_read_command(FALSE))
5030 log_write(L_smtp_connection, LOG_MAIN, "%s closed by EOF",
5031 smtp_get_connection_info());
5032 smtp_notquit_exit(US"tls-failed", NULL, NULL);
5036 /* It is perhaps arguable as to which exit ACL should be called here,
5037 but as it is probably a situation that almost never arises, it
5038 probably doesn't matter. We choose to call the real QUIT ACL, which in
5039 some sense is perhaps "right". */
5044 && ((rc = acl_check(ACL_WHERE_QUIT, NULL, acl_smtp_quit, &user_msg,
5045 &log_msg)) == ERROR))
5046 log_write(0, LOG_MAIN|LOG_PANIC, "ACL for QUIT returned ERROR: %s",
5049 smtp_respond(US"221", 3, TRUE, user_msg);
5051 smtp_printf("221 %s closing connection\r\n", smtp_active_hostname);
5052 log_write(L_smtp_connection, LOG_MAIN, "%s closed by QUIT",
5053 smtp_get_connection_info());
5058 smtp_printf("554 Security failure\r\n");
5061 tls_close(TRUE, TRUE);
5066 /* The ACL for QUIT is provided for gathering statistical information or
5067 similar; it does not affect the response code, but it can supply a custom
5071 smtp_quit_handler(&user_msg, &log_msg);
5077 smtp_rset_handler();
5078 smtp_reset(reset_point);
5085 smtp_printf("250 OK\r\n");
5089 /* Show ETRN/EXPN/VRFY if there's an ACL for checking hosts; if actually
5090 used, a check will be done for permitted hosts. Show STARTTLS only if not
5091 already in a TLS session and if it would be advertised in the EHLO
5096 smtp_printf("214-Commands supported:\r\n");
5100 Ustrcat(buffer, " AUTH");
5102 if (tls_in.active < 0 &&
5103 verify_check_host(&tls_advertise_hosts) != FAIL)
5104 Ustrcat(buffer, " STARTTLS");
5106 Ustrcat(buffer, " HELO EHLO MAIL RCPT DATA BDAT");
5107 Ustrcat(buffer, " NOOP QUIT RSET HELP");
5108 if (acl_smtp_etrn != NULL) Ustrcat(buffer, " ETRN");
5109 if (acl_smtp_expn != NULL) Ustrcat(buffer, " EXPN");
5110 if (acl_smtp_vrfy != NULL) Ustrcat(buffer, " VRFY");
5111 smtp_printf("214%s\r\n", buffer);
5117 incomplete_transaction_log(US"connection lost");
5118 smtp_notquit_exit(US"connection-lost", US"421",
5119 US"%s lost input connection", smtp_active_hostname);
5121 /* Don't log by default unless in the middle of a message, as some mailers
5122 just drop the call rather than sending QUIT, and it clutters up the logs.
5125 if (sender_address != NULL || recipients_count > 0)
5126 log_write(L_lost_incoming_connection,
5128 "unexpected %s while reading SMTP command from %s%s",
5129 sender_host_unknown? "EOF" : "disconnection",
5130 host_and_ident(FALSE), smtp_read_error);
5132 else log_write(L_smtp_connection, LOG_MAIN, "%s lost%s",
5133 smtp_get_connection_info(), smtp_read_error);
5141 if (sender_address != NULL)
5143 done = synprot_error(L_smtp_protocol_error, 503, NULL,
5144 US"ETRN is not permitted inside a transaction");
5148 log_write(L_etrn, LOG_MAIN, "ETRN %s received from %s", smtp_cmd_argument,
5149 host_and_ident(FALSE));
5151 if ((rc = acl_check(ACL_WHERE_ETRN, NULL, acl_smtp_etrn,
5152 &user_msg, &log_msg)) != OK)
5154 done = smtp_handle_acl_fail(ACL_WHERE_ETRN, rc, user_msg, log_msg);
5158 /* Compute the serialization key for this command. */
5160 etrn_serialize_key = string_sprintf("etrn-%s\n", smtp_cmd_data);
5162 /* If a command has been specified for running as a result of ETRN, we
5163 permit any argument to ETRN. If not, only the # standard form is permitted,
5164 since that is strictly the only kind of ETRN that can be implemented
5165 according to the RFC. */
5167 if (smtp_etrn_command != NULL)
5171 etrn_command = smtp_etrn_command;
5172 deliver_domain = smtp_cmd_data;
5173 rc = transport_set_up_command(&argv, smtp_etrn_command, TRUE, 0, NULL,
5174 US"ETRN processing", &error);
5175 deliver_domain = NULL;
5178 log_write(0, LOG_MAIN|LOG_PANIC, "failed to set up ETRN command: %s",
5180 smtp_printf("458 Internal failure\r\n");
5185 /* Else set up to call Exim with the -R option. */
5189 if (*smtp_cmd_data++ != '#')
5191 done = synprot_error(L_smtp_syntax_error, 501, NULL,
5192 US"argument must begin with #");
5195 etrn_command = US"exim -R";
5196 argv = CUSS child_exec_exim(CEE_RETURN_ARGV, TRUE, NULL, TRUE,
5197 *queue_name ? 4 : 2,
5198 US"-R", smtp_cmd_data,
5199 US"-MCG", queue_name);
5202 /* If we are host-testing, don't actually do anything. */
5208 debug_printf("ETRN command is: %s\n", etrn_command);
5209 debug_printf("ETRN command execution skipped\n");
5211 if (user_msg == NULL) smtp_printf("250 OK\r\n");
5212 else smtp_user_msg(US"250", user_msg);
5217 /* If ETRN queue runs are to be serialized, check the database to
5218 ensure one isn't already running. */
5220 if (smtp_etrn_serialize && !enq_start(etrn_serialize_key, 1))
5222 smtp_printf("458 Already processing %s\r\n", smtp_cmd_data);
5226 /* Fork a child process and run the command. We don't want to have to
5227 wait for the process at any point, so set SIGCHLD to SIG_IGN before
5228 forking. It should be set that way anyway for external incoming SMTP,
5229 but we save and restore to be tidy. If serialization is required, we
5230 actually run the command in yet another process, so we can wait for it
5231 to complete and then remove the serialization lock. */
5233 oldsignal = signal(SIGCHLD, SIG_IGN);
5235 if ((pid = fork()) == 0)
5237 smtp_input = FALSE; /* This process is not associated with the */
5238 (void)fclose(smtp_in); /* SMTP call any more. */
5239 (void)fclose(smtp_out);
5241 signal(SIGCHLD, SIG_DFL); /* Want to catch child */
5243 /* If not serializing, do the exec right away. Otherwise, fork down
5244 into another process. */
5246 if (!smtp_etrn_serialize || (pid = fork()) == 0)
5248 DEBUG(D_exec) debug_print_argv(argv);
5249 exim_nullstd(); /* Ensure std{in,out,err} exist */
5250 execv(CS argv[0], (char *const *)argv);
5251 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "exec of \"%s\" (ETRN) failed: %s",
5252 etrn_command, strerror(errno));
5253 _exit(EXIT_FAILURE); /* paranoia */
5256 /* Obey this if smtp_serialize and the 2nd fork yielded non-zero. That
5257 is, we are in the first subprocess, after forking again. All we can do
5258 for a failing fork is to log it. Otherwise, wait for the 2nd process to
5259 complete, before removing the serialization. */
5262 log_write(0, LOG_MAIN|LOG_PANIC, "2nd fork for serialized ETRN "
5263 "failed: %s", strerror(errno));
5267 DEBUG(D_any) debug_printf("waiting for serialized ETRN process %d\n",
5269 (void)wait(&status);
5270 DEBUG(D_any) debug_printf("serialized ETRN process %d ended\n",
5274 enq_end(etrn_serialize_key);
5275 _exit(EXIT_SUCCESS);
5278 /* Back in the top level SMTP process. Check that we started a subprocess
5279 and restore the signal state. */
5283 log_write(0, LOG_MAIN|LOG_PANIC, "fork of process for ETRN failed: %s",
5285 smtp_printf("458 Unable to fork process\r\n");
5286 if (smtp_etrn_serialize) enq_end(etrn_serialize_key);
5290 if (user_msg == NULL) smtp_printf("250 OK\r\n");
5291 else smtp_user_msg(US"250", user_msg);
5294 signal(SIGCHLD, oldsignal);
5299 done = synprot_error(L_smtp_syntax_error, 501, NULL,
5300 US"unexpected argument data");
5304 /* This currently happens only for NULLs, but could be extended. */
5307 done = synprot_error(L_smtp_syntax_error, 0, NULL, /* Just logs */
5308 US"NULL character(s) present (shown as '?')");
5309 smtp_printf("501 NULL characters are not allowed in SMTP commands\r\n");
5315 if (smtp_inend >= smtp_inbuffer + in_buffer_size)
5316 smtp_inend = smtp_inbuffer + in_buffer_size - 1;
5317 c = smtp_inend - smtp_inptr;
5318 if (c > 150) c = 150;
5320 incomplete_transaction_log(US"sync failure");
5321 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP protocol synchronization error "
5322 "(next input sent too soon: pipelining was%s advertised): "
5323 "rejected \"%s\" %s next input=\"%s\"",
5324 pipelining_advertised? "" : " not",
5325 smtp_cmd_buffer, host_and_ident(TRUE),
5326 string_printing(smtp_inptr));
5327 smtp_notquit_exit(US"synchronization-error", US"554",
5328 US"SMTP synchronization error");
5329 done = 1; /* Pretend eof - drops connection */
5333 case TOO_MANY_NONMAIL_CMD:
5334 s = smtp_cmd_buffer;
5335 while (*s != 0 && !isspace(*s)) s++;
5336 incomplete_transaction_log(US"too many non-mail commands");
5337 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
5338 "nonmail commands (last was \"%.*s\")", host_and_ident(FALSE),
5339 (int)(s - smtp_cmd_buffer), smtp_cmd_buffer);
5340 smtp_notquit_exit(US"bad-commands", US"554", US"Too many nonmail commands");
5341 done = 1; /* Pretend eof - drops connection */
5344 #ifdef SUPPORT_PROXY
5345 case PROXY_FAIL_IGNORE_CMD:
5346 smtp_printf("503 Command refused, required Proxy negotiation failed\r\n");
5351 if (unknown_command_count++ >= smtp_max_unknown_commands)
5353 log_write(L_smtp_syntax_error, LOG_MAIN,
5354 "SMTP syntax error in \"%s\" %s %s",
5355 string_printing(smtp_cmd_buffer), host_and_ident(TRUE),
5356 US"unrecognized command");
5357 incomplete_transaction_log(US"unrecognized command");
5358 smtp_notquit_exit(US"bad-commands", US"500",
5359 US"Too many unrecognized commands");
5361 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
5362 "unrecognized commands (last was \"%s\")", host_and_ident(FALSE),
5363 string_printing(smtp_cmd_buffer));
5366 done = synprot_error(L_smtp_syntax_error, 500, NULL,
5367 US"unrecognized command");
5371 /* This label is used by goto's inside loops that want to break out to
5372 the end of the command-processing loop. */
5375 last_was_rej_mail = was_rej_mail; /* Remember some last commands for */
5376 last_was_rcpt = was_rcpt; /* protocol error handling */
5380 return done - 2; /* Convert yield values */
5385 /* End of smtp_in.c */