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 (void) setsockopt(fd, SOL_SOCKET, SO_RCVTIMEO, CS 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.
808 Returns: Boolean success
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 int fd = fileno(smtp_in);
854 const char v2sig[12] = "\x0D\x0A\x0D\x0A\x00\x0D\x0A\x51\x55\x49\x54\x0A";
855 uschar *iptype; /* To display debug info */
857 struct timeval tvtmp;
858 socklen_t vslen = sizeof(struct timeval);
860 /* Save current socket timeout values */
861 get_ok = getsockopt(fd, SOL_SOCKET, SO_RCVTIMEO, CS &tvtmp, &vslen);
863 /* Proxy Protocol host must send header within a short time
864 (default 3 seconds) or it's considered invalid */
865 tv.tv_sec = PROXY_NEGOTIATION_TIMEOUT_SEC;
866 tv.tv_usec = PROXY_NEGOTIATION_TIMEOUT_USEC;
867 if (setsockopt(fd, SOL_SOCKET, SO_RCVTIMEO, CS &tv, sizeof(tv)) < 0)
872 /* The inbound host was declared to be a Proxy Protocol host, so
873 don't do a PEEK into the data, actually slurp it up. */
874 ret = recv(fd, &hdr, sizeof(hdr), 0);
876 while (ret == -1 && errno == EINTR);
881 if (ret >= 16 && memcmp(&hdr.v2, v2sig, 12) == 0)
883 uint8_t ver = (hdr.v2.ver_cmd & 0xf0) >> 4;
884 uint8_t cmd = (hdr.v2.ver_cmd & 0x0f);
886 /* May 2014: haproxy combined the version and command into one byte to
887 allow two full bytes for the length field in order to proxy SSL
888 connections. SSL Proxy is not supported in this version of Exim, but
889 must still seperate values here. */
893 DEBUG(D_receive) debug_printf("Invalid Proxy Protocol version: %d\n", ver);
896 DEBUG(D_receive) debug_printf("Detected PROXYv2 header\n");
897 /* The v2 header will always be 16 bytes per the spec. */
898 size = 16 + ntohs(hdr.v2.len);
901 DEBUG(D_receive) debug_printf("Truncated or too large PROXYv2 header (%d/%d)\n",
907 case 0x01: /* PROXY command */
910 case 0x11: /* TCPv4 address type */
912 tmpaddr.sin_addr.s_addr = hdr.v2.addr.ip4.src_addr;
913 inet_ntop(AF_INET, &tmpaddr.sin_addr, CS &tmpip, sizeof(tmpip));
914 if (!string_is_ip_address(US tmpip, NULL))
916 DEBUG(D_receive) debug_printf("Invalid %s source IP\n", iptype);
919 proxy_local_address = sender_host_address;
920 sender_host_address = string_copy(US tmpip);
921 tmpport = ntohs(hdr.v2.addr.ip4.src_port);
922 proxy_local_port = sender_host_port;
923 sender_host_port = tmpport;
924 /* Save dest ip/port */
925 tmpaddr.sin_addr.s_addr = hdr.v2.addr.ip4.dst_addr;
926 inet_ntop(AF_INET, &tmpaddr.sin_addr, CS &tmpip, sizeof(tmpip));
927 if (!string_is_ip_address(US tmpip, NULL))
929 DEBUG(D_receive) debug_printf("Invalid %s dest port\n", iptype);
932 proxy_external_address = string_copy(US tmpip);
933 tmpport = ntohs(hdr.v2.addr.ip4.dst_port);
934 proxy_external_port = tmpport;
936 case 0x21: /* TCPv6 address type */
938 memmove(tmpaddr6.sin6_addr.s6_addr, hdr.v2.addr.ip6.src_addr, 16);
939 inet_ntop(AF_INET6, &tmpaddr6.sin6_addr, CS &tmpip6, sizeof(tmpip6));
940 if (!string_is_ip_address(US tmpip6, NULL))
942 DEBUG(D_receive) debug_printf("Invalid %s source IP\n", iptype);
945 proxy_local_address = sender_host_address;
946 sender_host_address = string_copy(US tmpip6);
947 tmpport = ntohs(hdr.v2.addr.ip6.src_port);
948 proxy_local_port = sender_host_port;
949 sender_host_port = tmpport;
950 /* Save dest ip/port */
951 memmove(tmpaddr6.sin6_addr.s6_addr, hdr.v2.addr.ip6.dst_addr, 16);
952 inet_ntop(AF_INET6, &tmpaddr6.sin6_addr, CS &tmpip6, sizeof(tmpip6));
953 if (!string_is_ip_address(US tmpip6, NULL))
955 DEBUG(D_receive) debug_printf("Invalid %s dest port\n", iptype);
958 proxy_external_address = string_copy(US tmpip6);
959 tmpport = ntohs(hdr.v2.addr.ip6.dst_port);
960 proxy_external_port = tmpport;
964 debug_printf("Unsupported PROXYv2 connection type: 0x%02x\n",
968 /* Unsupported protocol, keep local connection address */
970 case 0x00: /* LOCAL command */
971 /* Keep local connection address for LOCAL */
975 debug_printf("Unsupported PROXYv2 command: 0x%x\n", cmd);
979 else if (ret >= 8 && memcmp(hdr.v1.line, "PROXY", 5) == 0)
981 uschar *p = string_copy(hdr.v1.line);
982 uschar *end = memchr(p, '\r', ret - 1);
983 uschar *sp; /* Utility variables follow */
987 if (!end || end[1] != '\n')
989 DEBUG(D_receive) debug_printf("Partial or invalid PROXY header\n");
992 *end = '\0'; /* Terminate the string */
993 size = end + 2 - hdr.v1.line; /* Skip header + CRLF */
994 DEBUG(D_receive) debug_printf("Detected PROXYv1 header\n");
995 /* Step through the string looking for the required fields. Ensure
996 strict adherance to required formatting, exit for any error. */
998 if (!isspace(*(p++)))
1000 DEBUG(D_receive) debug_printf("Missing space after PROXY command\n");
1003 if (!Ustrncmp(p, CCS"TCP4", 4))
1005 else if (!Ustrncmp(p,CCS"TCP6", 4))
1007 else if (!Ustrncmp(p,CCS"UNKNOWN", 7))
1009 iptype = US"Unknown";
1014 DEBUG(D_receive) debug_printf("Invalid TCP type\n");
1018 p += Ustrlen(iptype);
1019 if (!isspace(*(p++)))
1021 DEBUG(D_receive) debug_printf("Missing space after TCP4/6 command\n");
1024 /* Find the end of the arg */
1025 if ((sp = Ustrchr(p, ' ')) == NULL)
1028 debug_printf("Did not find proxied src %s\n", iptype);
1032 if(!string_is_ip_address(p, NULL))
1035 debug_printf("Proxied src arg is not an %s address\n", iptype);
1038 proxy_local_address = sender_host_address;
1039 sender_host_address = p;
1041 if ((sp = Ustrchr(p, ' ')) == NULL)
1044 debug_printf("Did not find proxy dest %s\n", iptype);
1048 if(!string_is_ip_address(p, NULL))
1051 debug_printf("Proxy dest arg is not an %s address\n", iptype);
1054 proxy_external_address = p;
1056 if ((sp = Ustrchr(p, ' ')) == NULL)
1058 DEBUG(D_receive) debug_printf("Did not find proxied src port\n");
1062 tmp_port = strtol(CCS p, &endc, 10);
1063 if (*endc || tmp_port == 0)
1066 debug_printf("Proxied src port '%s' not an integer\n", p);
1069 proxy_local_port = sender_host_port;
1070 sender_host_port = tmp_port;
1072 if ((sp = Ustrchr(p, '\0')) == NULL)
1074 DEBUG(D_receive) debug_printf("Did not find proxy dest port\n");
1077 tmp_port = strtol(CCS p, &endc, 10);
1078 if (*endc || tmp_port == 0)
1081 debug_printf("Proxy dest port '%s' not an integer\n", p);
1084 proxy_external_port = tmp_port;
1085 /* Already checked for /r /n above. Good V1 header received. */
1090 /* Wrong protocol */
1091 DEBUG(D_receive) debug_printf("Invalid proxy protocol version negotiation\n");
1096 restore_socket_timeout(fd, get_ok, &tvtmp, vslen);
1097 /* Don't flush any potential buffer contents. Any input should cause a
1098 synchronization failure */
1102 restore_socket_timeout(fd, get_ok, &tvtmp, vslen);
1104 debug_printf("Valid %s sender from Proxy Protocol header\n", iptype);
1105 return proxy_session;
1109 /*************************************************
1110 * Read one command line *
1111 *************************************************/
1113 /* Strictly, SMTP commands coming over the net are supposed to end with CRLF.
1114 There are sites that don't do this, and in any case internal SMTP probably
1115 should check only for LF. Consequently, we check here for LF only. The line
1116 ends up with [CR]LF removed from its end. If we get an overlong line, treat as
1117 an unknown command. The command is read into the global smtp_cmd_buffer so that
1118 it is available via $smtp_command.
1120 The character reading routine sets up a timeout for each block actually read
1121 from the input (which may contain more than one command). We set up a special
1122 signal handler that closes down the session on a timeout. Control does not
1123 return when it runs.
1126 check_sync if TRUE, check synchronization rules if global option is TRUE
1128 Returns: a code identifying the command (enumerated above)
1132 smtp_read_command(BOOL check_sync)
1137 BOOL hadnull = FALSE;
1139 os_non_restarting_signal(SIGALRM, command_timeout_handler);
1141 while ((c = (receive_getc)()) != '\n' && c != EOF)
1143 if (ptr >= smtp_cmd_buffer_size)
1145 os_non_restarting_signal(SIGALRM, sigalrm_handler);
1153 smtp_cmd_buffer[ptr++] = c;
1156 receive_linecount++; /* For BSMTP errors */
1157 os_non_restarting_signal(SIGALRM, sigalrm_handler);
1159 /* If hit end of file, return pseudo EOF command. Whether we have a
1160 part-line already read doesn't matter, since this is an error state. */
1162 if (c == EOF) return EOF_CMD;
1164 /* Remove any CR and white space at the end of the line, and terminate the
1167 while (ptr > 0 && isspace(smtp_cmd_buffer[ptr-1])) ptr--;
1168 smtp_cmd_buffer[ptr] = 0;
1170 DEBUG(D_receive) debug_printf("SMTP<< %s\n", smtp_cmd_buffer);
1172 /* NULLs are not allowed in SMTP commands */
1174 if (hadnull) return BADCHAR_CMD;
1176 /* Scan command list and return identity, having set the data pointer
1177 to the start of the actual data characters. Check for SMTP synchronization
1180 for (p = cmd_list; p < cmd_list_end; p++)
1182 #ifdef SUPPORT_PROXY
1183 /* Only allow QUIT command if Proxy Protocol parsing failed */
1184 if (proxy_session && proxy_session_failed)
1186 if (p->cmd != QUIT_CMD)
1191 && strncmpic(smtp_cmd_buffer, US p->name, p->len) == 0
1192 && ( smtp_cmd_buffer[p->len-1] == ':' /* "mail from:" or "rcpt to:" */
1193 || smtp_cmd_buffer[p->len] == 0
1194 || smtp_cmd_buffer[p->len] == ' '
1197 if (smtp_inptr < smtp_inend && /* Outstanding input */
1198 p->cmd < sync_cmd_limit && /* Command should sync */
1199 check_sync && /* Local flag set */
1200 smtp_enforce_sync && /* Global flag set */
1201 sender_host_address != NULL && /* Not local input */
1202 !sender_host_notsocket) /* Really is a socket */
1205 /* The variables $smtp_command and $smtp_command_argument point into the
1206 unmodified input buffer. A copy of the latter is taken for actual
1207 processing, so that it can be chopped up into separate parts if necessary,
1208 for example, when processing a MAIL command options such as SIZE that can
1209 follow the sender address. */
1211 smtp_cmd_argument = smtp_cmd_buffer + p->len;
1212 while (isspace(*smtp_cmd_argument)) smtp_cmd_argument++;
1213 Ustrcpy(smtp_data_buffer, smtp_cmd_argument);
1214 smtp_cmd_data = smtp_data_buffer;
1216 /* Count non-mail commands from those hosts that are controlled in this
1217 way. The default is all hosts. We don't waste effort checking the list
1218 until we get a non-mail command, but then cache the result to save checking
1219 again. If there's a DEFER while checking the host, assume it's in the list.
1221 Note that one instance of RSET, EHLO/HELO, and STARTTLS is allowed at the
1222 start of each incoming message by fiddling with the value in the table. */
1224 if (!p->is_mail_cmd)
1226 if (count_nonmail == TRUE_UNSET) count_nonmail =
1227 verify_check_host(&smtp_accept_max_nonmail_hosts) != FAIL;
1228 if (count_nonmail && ++nonmail_command_count > smtp_accept_max_nonmail)
1229 return TOO_MANY_NONMAIL_CMD;
1232 /* If there is data for a command that does not expect it, generate the
1235 return (p->has_arg || *smtp_cmd_data == 0)? p->cmd : BADARG_CMD;
1239 #ifdef SUPPORT_PROXY
1240 /* Only allow QUIT command if Proxy Protocol parsing failed */
1241 if (proxy_session && proxy_session_failed)
1242 return PROXY_FAIL_IGNORE_CMD;
1245 /* Enforce synchronization for unknown commands */
1247 if (smtp_inptr < smtp_inend && /* Outstanding input */
1248 check_sync && /* Local flag set */
1249 smtp_enforce_sync && /* Global flag set */
1250 sender_host_address != NULL && /* Not local input */
1251 !sender_host_notsocket) /* Really is a socket */
1259 /*************************************************
1260 * Recheck synchronization *
1261 *************************************************/
1263 /* Synchronization checks can never be perfect because a packet may be on its
1264 way but not arrived when the check is done. Such checks can in any case only be
1265 done when TLS is not in use. Normally, the checks happen when commands are
1266 read: Exim ensures that there is no more input in the input buffer. In normal
1267 cases, the response to the command will be fast, and there is no further check.
1269 However, for some commands an ACL is run, and that can include delays. In those
1270 cases, it is useful to do another check on the input just before sending the
1271 response. This also applies at the start of a connection. This function does
1272 that check by means of the select() function, as long as the facility is not
1273 disabled or inappropriate. A failure of select() is ignored.
1275 When there is unwanted input, we read it so that it appears in the log of the
1279 Returns: TRUE if all is well; FALSE if there is input pending
1287 struct timeval tzero;
1289 if (!smtp_enforce_sync || sender_host_address == NULL ||
1290 sender_host_notsocket || tls_in.active >= 0)
1293 fd = fileno(smtp_in);
1298 rc = select(fd + 1, (SELECT_ARG2_TYPE *)&fds, NULL, NULL, &tzero);
1300 if (rc <= 0) return TRUE; /* Not ready to read */
1302 if (rc < 0) return TRUE; /* End of file or error */
1305 rc = smtp_inend - smtp_inptr;
1306 if (rc > 150) rc = 150;
1313 /*************************************************
1314 * Forced closedown of call *
1315 *************************************************/
1317 /* This function is called from log.c when Exim is dying because of a serious
1318 disaster, and also from some other places. If an incoming non-batched SMTP
1319 channel is open, it swallows the rest of the incoming message if in the DATA
1320 phase, sends the reply string, and gives an error to all subsequent commands
1321 except QUIT. The existence of an SMTP call is detected by the non-NULLness of
1325 message SMTP reply string to send, excluding the code
1331 smtp_closedown(uschar *message)
1333 if (smtp_in == NULL || smtp_batched_input) return;
1334 receive_swallow_smtp();
1335 smtp_printf("421 %s\r\n", message);
1337 for (;;) switch(smtp_read_command(FALSE))
1343 smtp_printf("221 %s closing connection\r\n", smtp_active_hostname);
1348 smtp_printf("250 Reset OK\r\n");
1352 smtp_printf("421 %s\r\n", message);
1360 /*************************************************
1361 * Set up connection info for logging *
1362 *************************************************/
1364 /* This function is called when logging information about an SMTP connection.
1365 It sets up appropriate source information, depending on the type of connection.
1366 If sender_fullhost is NULL, we are at a very early stage of the connection;
1367 just use the IP address.
1370 Returns: a string describing the connection
1374 smtp_get_connection_info(void)
1376 const uschar * hostname = sender_fullhost
1377 ? sender_fullhost : sender_host_address;
1380 return string_sprintf("SMTP connection from %s", hostname);
1382 if (sender_host_unknown || sender_host_notsocket)
1383 return string_sprintf("SMTP connection from %s", sender_ident);
1386 return string_sprintf("SMTP connection from %s (via inetd)", hostname);
1388 if (LOGGING(incoming_interface) && interface_address != NULL)
1389 return string_sprintf("SMTP connection from %s I=[%s]:%d", hostname,
1390 interface_address, interface_port);
1392 return string_sprintf("SMTP connection from %s", hostname);
1398 /* Append TLS-related information to a log line
1401 s String under construction: allocated string to extend, or NULL
1402 sizep Pointer to current allocation size (update on return), or NULL
1403 ptrp Pointer to index for new entries in string (update on return), or NULL
1405 Returns: Allocated string or NULL
1408 s_tlslog(uschar * s, int * sizep, int * ptrp)
1410 int size = sizep ? *sizep : 0;
1411 int ptr = ptrp ? *ptrp : 0;
1413 if (LOGGING(tls_cipher) && tls_in.cipher != NULL)
1414 s = string_append(s, &size, &ptr, 2, US" X=", tls_in.cipher);
1415 if (LOGGING(tls_certificate_verified) && tls_in.cipher != NULL)
1416 s = string_append(s, &size, &ptr, 2, US" CV=",
1417 tls_in.certificate_verified? "yes":"no");
1418 if (LOGGING(tls_peerdn) && tls_in.peerdn != NULL)
1419 s = string_append(s, &size, &ptr, 3, US" DN=\"",
1420 string_printing(tls_in.peerdn), US"\"");
1421 if (LOGGING(tls_sni) && tls_in.sni != NULL)
1422 s = string_append(s, &size, &ptr, 3, US" SNI=\"",
1423 string_printing(tls_in.sni), US"\"");
1428 if (sizep) *sizep = size;
1429 if (ptrp) *ptrp = ptr;
1435 /*************************************************
1436 * Log lack of MAIL if so configured *
1437 *************************************************/
1439 /* This function is called when an SMTP session ends. If the log selector
1440 smtp_no_mail is set, write a log line giving some details of what has happened
1441 in the SMTP session.
1448 smtp_log_no_mail(void)
1453 if (smtp_mailcmd_count > 0 || !LOGGING(smtp_no_mail))
1459 if (sender_host_authenticated != NULL)
1461 s = string_append(s, &size, &ptr, 2, US" A=", sender_host_authenticated);
1462 if (authenticated_id != NULL)
1463 s = string_append(s, &size, &ptr, 2, US":", authenticated_id);
1467 s = s_tlslog(s, &size, &ptr);
1470 sep = (smtp_connection_had[SMTP_HBUFF_SIZE-1] != SCH_NONE)?
1471 US" C=..." : US" C=";
1472 for (i = smtp_ch_index; i < SMTP_HBUFF_SIZE; i++)
1474 if (smtp_connection_had[i] != SCH_NONE)
1476 s = string_append(s, &size, &ptr, 2, sep,
1477 smtp_names[smtp_connection_had[i]]);
1482 for (i = 0; i < smtp_ch_index; i++)
1484 s = string_append(s, &size, &ptr, 2, sep, smtp_names[smtp_connection_had[i]]);
1488 if (s != NULL) s[ptr] = 0; else s = US"";
1489 log_write(0, LOG_MAIN, "no MAIL in SMTP connection from %s D=%s%s",
1490 host_and_ident(FALSE),
1491 readconf_printtime( (int) ((long)time(NULL) - (long)smtp_connection_start)),
1497 /*************************************************
1498 * Check HELO line and set sender_helo_name *
1499 *************************************************/
1501 /* Check the format of a HELO line. The data for HELO/EHLO is supposed to be
1502 the domain name of the sending host, or an ip literal in square brackets. The
1503 arrgument is placed in sender_helo_name, which is in malloc store, because it
1504 must persist over multiple incoming messages. If helo_accept_junk is set, this
1505 host is permitted to send any old junk (needed for some broken hosts).
1506 Otherwise, helo_allow_chars can be used for rogue characters in general
1507 (typically people want to let in underscores).
1510 s the data portion of the line (already past any white space)
1512 Returns: TRUE or FALSE
1516 check_helo(uschar *s)
1519 uschar *end = s + Ustrlen(s);
1520 BOOL yield = helo_accept_junk;
1522 /* Discard any previous helo name */
1524 if (sender_helo_name != NULL)
1526 store_free(sender_helo_name);
1527 sender_helo_name = NULL;
1530 /* Skip tests if junk is permitted. */
1534 /* Allow the new standard form for IPv6 address literals, namely,
1535 [IPv6:....], and because someone is bound to use it, allow an equivalent
1536 IPv4 form. Allow plain addresses as well. */
1543 if (strncmpic(s, US"[IPv6:", 6) == 0)
1544 yield = (string_is_ip_address(s+6, NULL) == 6);
1545 else if (strncmpic(s, US"[IPv4:", 6) == 0)
1546 yield = (string_is_ip_address(s+6, NULL) == 4);
1548 yield = (string_is_ip_address(s+1, NULL) != 0);
1553 /* Non-literals must be alpha, dot, hyphen, plus any non-valid chars
1554 that have been configured (usually underscore - sigh). */
1561 if (!isalnum(*s) && *s != '.' && *s != '-' &&
1562 Ustrchr(helo_allow_chars, *s) == NULL)
1572 /* Save argument if OK */
1574 if (yield) sender_helo_name = string_copy_malloc(start);
1582 /*************************************************
1583 * Extract SMTP command option *
1584 *************************************************/
1586 /* This function picks the next option setting off the end of smtp_cmd_data. It
1587 is called for MAIL FROM and RCPT TO commands, to pick off the optional ESMTP
1588 things that can appear there.
1591 name point this at the name
1592 value point this at the data string
1594 Returns: TRUE if found an option
1598 extract_option(uschar **name, uschar **value)
1601 uschar *v = smtp_cmd_data + Ustrlen(smtp_cmd_data) - 1;
1602 while (isspace(*v)) v--;
1604 while (v > smtp_cmd_data && *v != '=' && !isspace(*v)) v--;
1609 while(isalpha(n[-1])) n--;
1610 /* RFC says SP, but TAB seen in wild and other major MTAs accept it */
1611 if (!isspace(n[-1])) return FALSE;
1617 if (v == smtp_cmd_data) return FALSE;
1629 /*************************************************
1630 * Reset for new message *
1631 *************************************************/
1633 /* This function is called whenever the SMTP session is reset from
1634 within either of the setup functions.
1636 Argument: the stacking pool storage reset point
1641 smtp_reset(void *reset_point)
1643 store_reset(reset_point);
1644 recipients_list = NULL;
1645 rcpt_count = rcpt_defer_count = rcpt_fail_count =
1646 raw_recipients_count = recipients_count = recipients_list_max = 0;
1647 cancel_cutthrough_connection("smtp reset");
1648 message_linecount = 0;
1650 acl_added_headers = NULL;
1651 acl_removed_headers = NULL;
1652 queue_only_policy = FALSE;
1653 rcpt_smtp_response = NULL;
1654 rcpt_smtp_response_same = TRUE;
1655 rcpt_in_progress = FALSE;
1656 deliver_freeze = FALSE; /* Can be set by ACL */
1657 freeze_tell = freeze_tell_config; /* Can be set by ACL */
1658 fake_response = OK; /* Can be set by ACL */
1659 #ifdef WITH_CONTENT_SCAN
1660 no_mbox_unspool = FALSE; /* Can be set by ACL */
1662 submission_mode = FALSE; /* Can be set by ACL */
1663 suppress_local_fixups = suppress_local_fixups_default; /* Can be set by ACL */
1664 active_local_from_check = local_from_check; /* Can be set by ACL */
1665 active_local_sender_retain = local_sender_retain; /* Can be set by ACL */
1666 sender_address = NULL;
1667 submission_name = NULL; /* Can be set by ACL */
1668 raw_sender = NULL; /* After SMTP rewrite, before qualifying */
1669 sender_address_unrewritten = NULL; /* Set only after verify rewrite */
1670 sender_verified_list = NULL; /* No senders verified */
1671 memset(sender_address_cache, 0, sizeof(sender_address_cache));
1672 memset(sender_domain_cache, 0, sizeof(sender_domain_cache));
1674 authenticated_sender = NULL;
1675 #ifdef EXPERIMENTAL_BRIGHTMAIL
1677 bmi_verdicts = NULL;
1679 #ifndef DISABLE_DKIM
1680 dkim_signers = NULL;
1681 dkim_disable_verify = FALSE;
1682 dkim_collect_input = FALSE;
1686 #ifndef DISABLE_PRDR
1687 prdr_requested = FALSE;
1689 #ifdef EXPERIMENTAL_SPF
1690 spf_header_comment = NULL;
1691 spf_received = NULL;
1693 spf_smtp_comment = NULL;
1696 message_smtputf8 = FALSE;
1698 body_linecount = body_zerocount = 0;
1700 sender_rate = sender_rate_limit = sender_rate_period = NULL;
1701 ratelimiters_mail = NULL; /* Updated by ratelimit ACL condition */
1702 /* Note that ratelimiters_conn persists across resets. */
1704 /* Reset message ACL variables */
1708 /* The message body variables use malloc store. They may be set if this is
1709 not the first message in an SMTP session and the previous message caused them
1710 to be referenced in an ACL. */
1712 if (message_body != NULL)
1714 store_free(message_body);
1715 message_body = NULL;
1718 if (message_body_end != NULL)
1720 store_free(message_body_end);
1721 message_body_end = NULL;
1724 /* Warning log messages are also saved in malloc store. They are saved to avoid
1725 repetition in the same message, but it seems right to repeat them for different
1728 while (acl_warn_logged != NULL)
1730 string_item *this = acl_warn_logged;
1731 acl_warn_logged = acl_warn_logged->next;
1740 /*************************************************
1741 * Initialize for incoming batched SMTP message *
1742 *************************************************/
1744 /* This function is called from smtp_setup_msg() in the case when
1745 smtp_batched_input is true. This happens when -bS is used to pass a whole batch
1746 of messages in one file with SMTP commands between them. All errors must be
1747 reported by sending a message, and only MAIL FROM, RCPT TO, and DATA are
1748 relevant. After an error on a sender, or an invalid recipient, the remainder
1749 of the message is skipped. The value of received_protocol is already set.
1752 Returns: > 0 message successfully started (reached DATA)
1753 = 0 QUIT read or end of file reached
1754 < 0 should not occur
1758 smtp_setup_batch_msg(void)
1761 void *reset_point = store_get(0);
1763 /* Save the line count at the start of each transaction - single commands
1764 like HELO and RSET count as whole transactions. */
1766 bsmtp_transaction_linecount = receive_linecount;
1768 if ((receive_feof)()) return 0; /* Treat EOF as QUIT */
1770 smtp_reset(reset_point); /* Reset for start of message */
1772 /* Deal with SMTP commands. This loop is exited by setting done to a POSITIVE
1773 value. The values are 2 larger than the required yield of the function. */
1778 uschar *recipient = NULL;
1779 int start, end, sender_domain, recipient_domain;
1781 switch(smtp_read_command(FALSE))
1783 /* The HELO/EHLO commands set sender_address_helo if they have
1784 valid data; otherwise they are ignored, except that they do
1785 a reset of the state. */
1790 check_helo(smtp_cmd_data);
1794 smtp_reset(reset_point);
1795 bsmtp_transaction_linecount = receive_linecount;
1799 /* The MAIL FROM command requires an address as an operand. All we
1800 do here is to parse it for syntactic correctness. The form "<>" is
1801 a special case which converts into an empty string. The start/end
1802 pointers in the original are not used further for this address, as
1803 it is the canonical extracted address which is all that is kept. */
1806 smtp_mailcmd_count++; /* Count for no-mail log */
1807 if (sender_address != NULL)
1808 /* The function moan_smtp_batch() does not return. */
1809 moan_smtp_batch(smtp_cmd_buffer, "503 Sender already given");
1811 if (smtp_cmd_data[0] == 0)
1812 /* The function moan_smtp_batch() does not return. */
1813 moan_smtp_batch(smtp_cmd_buffer, "501 MAIL FROM must have an address operand");
1815 /* Reset to start of message */
1817 smtp_reset(reset_point);
1819 /* Apply SMTP rewrite */
1821 raw_sender = ((rewrite_existflags & rewrite_smtp) != 0)?
1822 rewrite_one(smtp_cmd_data, rewrite_smtp|rewrite_smtp_sender, NULL, FALSE,
1823 US"", global_rewrite_rules) : smtp_cmd_data;
1825 /* Extract the address; the TRUE flag allows <> as valid */
1828 parse_extract_address(raw_sender, &errmess, &start, &end, &sender_domain,
1831 if (raw_sender == NULL)
1832 /* The function moan_smtp_batch() does not return. */
1833 moan_smtp_batch(smtp_cmd_buffer, "501 %s", errmess);
1835 sender_address = string_copy(raw_sender);
1837 /* Qualify unqualified sender addresses if permitted to do so. */
1839 if (sender_domain == 0 && sender_address[0] != 0 && sender_address[0] != '@')
1841 if (allow_unqualified_sender)
1843 sender_address = rewrite_address_qualify(sender_address, FALSE);
1844 DEBUG(D_receive) debug_printf("unqualified address %s accepted "
1845 "and rewritten\n", raw_sender);
1847 /* The function moan_smtp_batch() does not return. */
1848 else moan_smtp_batch(smtp_cmd_buffer, "501 sender address must contain "
1854 /* The RCPT TO command requires an address as an operand. All we do
1855 here is to parse it for syntactic correctness. There may be any number
1856 of RCPT TO commands, specifying multiple senders. We build them all into
1857 a data structure that is in argc/argv format. The start/end values
1858 given by parse_extract_address are not used, as we keep only the
1859 extracted address. */
1862 if (sender_address == NULL)
1863 /* The function moan_smtp_batch() does not return. */
1864 moan_smtp_batch(smtp_cmd_buffer, "503 No sender yet given");
1866 if (smtp_cmd_data[0] == 0)
1867 /* The function moan_smtp_batch() does not return. */
1868 moan_smtp_batch(smtp_cmd_buffer, "501 RCPT TO must have an address operand");
1870 /* Check maximum number allowed */
1872 if (recipients_max > 0 && recipients_count + 1 > recipients_max)
1873 /* The function moan_smtp_batch() does not return. */
1874 moan_smtp_batch(smtp_cmd_buffer, "%s too many recipients",
1875 recipients_max_reject? "552": "452");
1877 /* Apply SMTP rewrite, then extract address. Don't allow "<>" as a
1878 recipient address */
1880 recipient = rewrite_existflags & rewrite_smtp
1881 ? rewrite_one(smtp_cmd_data, rewrite_smtp, NULL, FALSE, US"",
1882 global_rewrite_rules)
1885 recipient = parse_extract_address(recipient, &errmess, &start, &end,
1886 &recipient_domain, FALSE);
1889 /* The function moan_smtp_batch() does not return. */
1890 moan_smtp_batch(smtp_cmd_buffer, "501 %s", errmess);
1892 /* If the recipient address is unqualified, qualify it if permitted. Then
1893 add it to the list of recipients. */
1895 if (recipient_domain == 0)
1897 if (allow_unqualified_recipient)
1899 DEBUG(D_receive) debug_printf("unqualified address %s accepted\n",
1901 recipient = rewrite_address_qualify(recipient, TRUE);
1903 /* The function moan_smtp_batch() does not return. */
1904 else moan_smtp_batch(smtp_cmd_buffer, "501 recipient address must contain "
1907 receive_add_recipient(recipient, -1);
1911 /* The DATA command is legal only if it follows successful MAIL FROM
1912 and RCPT TO commands. This function is complete when a valid DATA
1913 command is encountered. */
1916 if (sender_address == NULL || recipients_count <= 0)
1918 /* The function moan_smtp_batch() does not return. */
1919 if (sender_address == NULL)
1920 moan_smtp_batch(smtp_cmd_buffer,
1921 "503 MAIL FROM:<sender> command must precede DATA");
1923 moan_smtp_batch(smtp_cmd_buffer,
1924 "503 RCPT TO:<recipient> must precede DATA");
1928 done = 3; /* DATA successfully achieved */
1929 message_ended = END_NOTENDED; /* Indicate in middle of message */
1934 /* The VRFY, EXPN, HELP, ETRN, and NOOP commands are ignored. */
1941 bsmtp_transaction_linecount = receive_linecount;
1952 /* The function moan_smtp_batch() does not return. */
1953 moan_smtp_batch(smtp_cmd_buffer, "501 Unexpected argument data");
1958 /* The function moan_smtp_batch() does not return. */
1959 moan_smtp_batch(smtp_cmd_buffer, "501 Unexpected NULL in SMTP command");
1964 /* The function moan_smtp_batch() does not return. */
1965 moan_smtp_batch(smtp_cmd_buffer, "500 Command unrecognized");
1970 return done - 2; /* Convert yield values */
1976 /*************************************************
1977 * Start an SMTP session *
1978 *************************************************/
1980 /* This function is called at the start of an SMTP session. Thereafter,
1981 smtp_setup_msg() is called to initiate each separate message. This
1982 function does host-specific testing, and outputs the banner line.
1985 Returns: FALSE if the session can not continue; something has
1986 gone wrong, or the connection to the host is blocked
1990 smtp_start_session(void)
1994 uschar *user_msg, *log_msg;
1998 smtp_connection_start = time(NULL);
1999 for (smtp_ch_index = 0; smtp_ch_index < SMTP_HBUFF_SIZE; smtp_ch_index++)
2000 smtp_connection_had[smtp_ch_index] = SCH_NONE;
2003 /* Default values for certain variables */
2005 helo_seen = esmtp = helo_accept_junk = FALSE;
2006 smtp_mailcmd_count = 0;
2007 count_nonmail = TRUE_UNSET;
2008 synprot_error_count = unknown_command_count = nonmail_command_count = 0;
2009 smtp_delay_mail = smtp_rlm_base;
2010 auth_advertised = FALSE;
2011 pipelining_advertised = FALSE;
2012 pipelining_enable = TRUE;
2013 sync_cmd_limit = NON_SYNC_CMD_NON_PIPELINING;
2014 smtp_exit_function_called = FALSE; /* For avoiding loop in not-quit exit */
2016 /* If receiving by -bs from a trusted user, or testing with -bh, we allow
2017 authentication settings from -oMaa to remain in force. */
2019 if (!host_checking && !sender_host_notsocket) sender_host_authenticated = NULL;
2020 authenticated_by = NULL;
2023 tls_in.cipher = tls_in.peerdn = NULL;
2024 tls_in.ourcert = tls_in.peercert = NULL;
2026 tls_in.ocsp = OCSP_NOT_REQ;
2027 tls_advertised = FALSE;
2029 dsn_advertised = FALSE;
2031 smtputf8_advertised = FALSE;
2034 /* Reset ACL connection variables */
2038 /* Allow for trailing 0 in the command and data buffers. */
2040 if (!(smtp_cmd_buffer = US malloc(2*smtp_cmd_buffer_size + 2)))
2041 log_write(0, LOG_MAIN|LOG_PANIC_DIE,
2042 "malloc() failed for SMTP command buffer");
2044 smtp_cmd_buffer[0] = 0;
2045 smtp_data_buffer = smtp_cmd_buffer + smtp_cmd_buffer_size + 1;
2047 /* For batched input, the protocol setting can be overridden from the
2048 command line by a trusted caller. */
2050 if (smtp_batched_input)
2052 if (!received_protocol) received_protocol = US"local-bsmtp";
2055 /* For non-batched SMTP input, the protocol setting is forced here. It will be
2056 reset later if any of EHLO/AUTH/STARTTLS are received. */
2060 (sender_host_address ? protocols : protocols_local) [pnormal];
2062 /* Set up the buffer for inputting using direct read() calls, and arrange to
2063 call the local functions instead of the standard C ones. */
2065 if (!(smtp_inbuffer = (uschar *)malloc(in_buffer_size)))
2066 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "malloc() failed for SMTP input buffer");
2068 receive_getc = smtp_getc;
2069 receive_get_cache = smtp_get_cache;
2070 receive_ungetc = smtp_ungetc;
2071 receive_feof = smtp_feof;
2072 receive_ferror = smtp_ferror;
2073 receive_smtp_buffered = smtp_buffered;
2074 smtp_inptr = smtp_inend = smtp_inbuffer;
2075 smtp_had_eof = smtp_had_error = 0;
2077 /* Set up the message size limit; this may be host-specific */
2079 thismessage_size_limit = expand_string_integer(message_size_limit, TRUE);
2080 if (expand_string_message != NULL)
2082 if (thismessage_size_limit == -1)
2083 log_write(0, LOG_MAIN|LOG_PANIC, "unable to expand message_size_limit: "
2084 "%s", expand_string_message);
2086 log_write(0, LOG_MAIN|LOG_PANIC, "invalid message_size_limit: "
2087 "%s", expand_string_message);
2088 smtp_closedown(US"Temporary local problem - please try later");
2092 /* When a message is input locally via the -bs or -bS options, sender_host_
2093 unknown is set unless -oMa was used to force an IP address, in which case it
2094 is checked like a real remote connection. When -bs is used from inetd, this
2095 flag is not set, causing the sending host to be checked. The code that deals
2096 with IP source routing (if configured) is never required for -bs or -bS and
2097 the flag sender_host_notsocket is used to suppress it.
2099 If smtp_accept_max and smtp_accept_reserve are set, keep some connections in
2100 reserve for certain hosts and/or networks. */
2102 if (!sender_host_unknown)
2105 BOOL reserved_host = FALSE;
2107 /* Look up IP options (source routing info) on the socket if this is not an
2108 -oMa "host", and if any are found, log them and drop the connection.
2110 Linux (and others now, see below) is different to everyone else, so there
2111 has to be some conditional compilation here. Versions of Linux before 2.1.15
2112 used a structure whose name was "options". Somebody finally realized that
2113 this name was silly, and it got changed to "ip_options". I use the
2114 newer name here, but there is a fudge in the script that sets up os.h
2115 to define a macro in older Linux systems.
2117 Sigh. Linux is a fast-moving target. Another generation of Linux uses
2118 glibc 2, which has chosen ip_opts for the structure name. This is now
2119 really a glibc thing rather than a Linux thing, so the condition name
2120 has been changed to reflect this. It is relevant also to GNU/Hurd.
2122 Mac OS 10.x (Darwin) is like the later glibc versions, but without the
2123 setting of the __GLIBC__ macro, so we can't detect it automatically. There's
2124 a special macro defined in the os.h file.
2126 Some DGUX versions on older hardware appear not to support IP options at
2127 all, so there is now a general macro which can be set to cut out this
2130 How to do this properly in IPv6 is not yet known. */
2132 #if !HAVE_IPV6 && !defined(NO_IP_OPTIONS)
2134 #ifdef GLIBC_IP_OPTIONS
2135 #if (!defined __GLIBC__) || (__GLIBC__ < 2)
2140 #elif defined DARWIN_IP_OPTIONS
2146 if (!host_checking && !sender_host_notsocket)
2149 EXIM_SOCKLEN_T optlen = sizeof(struct ip_options) + MAX_IPOPTLEN;
2150 struct ip_options *ipopt = store_get(optlen);
2152 struct ip_opts ipoptblock;
2153 struct ip_opts *ipopt = &ipoptblock;
2154 EXIM_SOCKLEN_T optlen = sizeof(ipoptblock);
2156 struct ipoption ipoptblock;
2157 struct ipoption *ipopt = &ipoptblock;
2158 EXIM_SOCKLEN_T optlen = sizeof(ipoptblock);
2161 /* Occasional genuine failures of getsockopt() have been seen - for
2162 example, "reset by peer". Therefore, just log and give up on this
2163 call, unless the error is ENOPROTOOPT. This error is given by systems
2164 that have the interfaces but not the mechanism - e.g. GNU/Hurd at the time
2165 of writing. So for that error, carry on - we just can't do an IP options
2168 DEBUG(D_receive) debug_printf("checking for IP options\n");
2170 if (getsockopt(fileno(smtp_out), IPPROTO_IP, IP_OPTIONS, (uschar *)(ipopt),
2173 if (errno != ENOPROTOOPT)
2175 log_write(0, LOG_MAIN, "getsockopt() failed from %s: %s",
2176 host_and_ident(FALSE), strerror(errno));
2177 smtp_printf("451 SMTP service not available\r\n");
2182 /* Deal with any IP options that are set. On the systems I have looked at,
2183 the value of MAX_IPOPTLEN has been 40, meaning that there should never be
2184 more logging data than will fit in big_buffer. Nevertheless, after somebody
2185 questioned this code, I've added in some paranoid checking. */
2187 else if (optlen > 0)
2189 uschar *p = big_buffer;
2190 uschar *pend = big_buffer + big_buffer_size;
2191 uschar *opt, *adptr;
2193 struct in_addr addr;
2196 uschar *optstart = (uschar *)(ipopt->__data);
2198 uschar *optstart = (uschar *)(ipopt->ip_opts);
2200 uschar *optstart = (uschar *)(ipopt->ipopt_list);
2203 DEBUG(D_receive) debug_printf("IP options exist\n");
2205 Ustrcpy(p, "IP options on incoming call:");
2208 for (opt = optstart; opt != NULL &&
2209 opt < (uschar *)(ipopt) + optlen;)
2223 if (!string_format(p, pend-p, " %s [@%s",
2224 (*opt == IPOPT_SSRR)? "SSRR" : "LSRR",
2226 inet_ntoa(*((struct in_addr *)(&(ipopt->faddr))))))
2228 inet_ntoa(ipopt->ip_dst)))
2230 inet_ntoa(ipopt->ipopt_dst)))
2238 optcount = (opt[1] - 3) / sizeof(struct in_addr);
2240 while (optcount-- > 0)
2242 memcpy(&addr, adptr, sizeof(addr));
2243 if (!string_format(p, pend - p - 1, "%s%s",
2244 (optcount == 0)? ":" : "@", inet_ntoa(addr)))
2250 adptr += sizeof(struct in_addr);
2259 if (pend - p < 4 + 3*opt[1]) { opt = NULL; break; }
2262 for (i = 0; i < opt[1]; i++)
2264 sprintf(CS p, "%2.2x ", opt[i]);
2275 log_write(0, LOG_MAIN, "%s", big_buffer);
2277 /* Refuse any call with IP options. This is what tcpwrappers 7.5 does. */
2279 log_write(0, LOG_MAIN|LOG_REJECT,
2280 "connection from %s refused (IP options)", host_and_ident(FALSE));
2282 smtp_printf("554 SMTP service not available\r\n");
2286 /* Length of options = 0 => there are no options */
2288 else DEBUG(D_receive) debug_printf("no IP options found\n");
2290 #endif /* HAVE_IPV6 && !defined(NO_IP_OPTIONS) */
2292 /* Set keep-alive in socket options. The option is on by default. This
2293 setting is an attempt to get rid of some hanging connections that stick in
2294 read() when the remote end (usually a dialup) goes away. */
2296 if (smtp_accept_keepalive && !sender_host_notsocket)
2297 ip_keepalive(fileno(smtp_out), sender_host_address, FALSE);
2299 /* If the current host matches host_lookup, set the name by doing a
2300 reverse lookup. On failure, sender_host_name will be NULL and
2301 host_lookup_failed will be TRUE. This may or may not be serious - optional
2304 if (verify_check_host(&host_lookup) == OK)
2306 (void)host_name_lookup();
2307 host_build_sender_fullhost();
2310 /* Delay this until we have the full name, if it is looked up. */
2312 set_process_info("handling incoming connection from %s",
2313 host_and_ident(FALSE));
2315 /* Expand smtp_receive_timeout, if needed */
2317 if (smtp_receive_timeout_s)
2320 if ( !(exp = expand_string(smtp_receive_timeout_s))
2322 || (smtp_receive_timeout = readconf_readtime(exp, 0, FALSE)) < 0
2324 log_write(0, LOG_MAIN|LOG_PANIC,
2325 "bad value for smtp_receive_timeout: '%s'", exp ? exp : US"");
2328 /* Start up TLS if tls_on_connect is set. This is for supporting the legacy
2329 smtps port for use with older style SSL MTAs. */
2332 if (tls_in.on_connect && tls_server_start(tls_require_ciphers) != OK)
2336 /* Test for explicit connection rejection */
2338 if (verify_check_host(&host_reject_connection) == OK)
2340 log_write(L_connection_reject, LOG_MAIN|LOG_REJECT, "refused connection "
2341 "from %s (host_reject_connection)", host_and_ident(FALSE));
2342 smtp_printf("554 SMTP service not available\r\n");
2346 /* Test with TCP Wrappers if so configured. There is a problem in that
2347 hosts_ctl() returns 0 (deny) under a number of system failure circumstances,
2348 such as disks dying. In these cases, it is desirable to reject with a 4xx
2349 error instead of a 5xx error. There isn't a "right" way to detect such
2350 problems. The following kludge is used: errno is zeroed before calling
2351 hosts_ctl(). If the result is "reject", a 5xx error is given only if the
2352 value of errno is 0 or ENOENT (which happens if /etc/hosts.{allow,deny} does
2355 #ifdef USE_TCP_WRAPPERS
2357 tcp_wrappers_name = expand_string(tcp_wrappers_daemon_name);
2358 if (tcp_wrappers_name == NULL)
2360 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "Expansion of \"%s\" "
2361 "(tcp_wrappers_name) failed: %s", string_printing(tcp_wrappers_name),
2362 expand_string_message);
2364 if (!hosts_ctl(tcp_wrappers_name,
2365 (sender_host_name == NULL)? STRING_UNKNOWN : CS sender_host_name,
2366 (sender_host_address == NULL)? STRING_UNKNOWN : CS sender_host_address,
2367 (sender_ident == NULL)? STRING_UNKNOWN : CS sender_ident))
2369 if (errno == 0 || errno == ENOENT)
2371 HDEBUG(D_receive) debug_printf("tcp wrappers rejection\n");
2372 log_write(L_connection_reject,
2373 LOG_MAIN|LOG_REJECT, "refused connection from %s "
2374 "(tcp wrappers)", host_and_ident(FALSE));
2375 smtp_printf("554 SMTP service not available\r\n");
2379 int save_errno = errno;
2380 HDEBUG(D_receive) debug_printf("tcp wrappers rejected with unexpected "
2381 "errno value %d\n", save_errno);
2382 log_write(L_connection_reject,
2383 LOG_MAIN|LOG_REJECT, "temporarily refused connection from %s "
2384 "(tcp wrappers errno=%d)", host_and_ident(FALSE), save_errno);
2385 smtp_printf("451 Temporary local problem - please try later\r\n");
2391 /* Check for reserved slots. The value of smtp_accept_count has already been
2392 incremented to include this process. */
2394 if (smtp_accept_max > 0 &&
2395 smtp_accept_count > smtp_accept_max - smtp_accept_reserve)
2397 if ((rc = verify_check_host(&smtp_reserve_hosts)) != OK)
2399 log_write(L_connection_reject,
2400 LOG_MAIN, "temporarily refused connection from %s: not in "
2401 "reserve list: connected=%d max=%d reserve=%d%s",
2402 host_and_ident(FALSE), smtp_accept_count - 1, smtp_accept_max,
2403 smtp_accept_reserve, (rc == DEFER)? " (lookup deferred)" : "");
2404 smtp_printf("421 %s: Too many concurrent SMTP connections; "
2405 "please try again later\r\n", smtp_active_hostname);
2408 reserved_host = TRUE;
2411 /* If a load level above which only messages from reserved hosts are
2412 accepted is set, check the load. For incoming calls via the daemon, the
2413 check is done in the superior process if there are no reserved hosts, to
2414 save a fork. In all cases, the load average will already be available
2415 in a global variable at this point. */
2417 if (smtp_load_reserve >= 0 &&
2418 load_average > smtp_load_reserve &&
2420 verify_check_host(&smtp_reserve_hosts) != OK)
2422 log_write(L_connection_reject,
2423 LOG_MAIN, "temporarily refused connection from %s: not in "
2424 "reserve list and load average = %.2f", host_and_ident(FALSE),
2425 (double)load_average/1000.0);
2426 smtp_printf("421 %s: Too much load; please try again later\r\n",
2427 smtp_active_hostname);
2431 /* Determine whether unqualified senders or recipients are permitted
2432 for this host. Unfortunately, we have to do this every time, in order to
2433 set the flags so that they can be inspected when considering qualifying
2434 addresses in the headers. For a site that permits no qualification, this
2435 won't take long, however. */
2437 allow_unqualified_sender =
2438 verify_check_host(&sender_unqualified_hosts) == OK;
2440 allow_unqualified_recipient =
2441 verify_check_host(&recipient_unqualified_hosts) == OK;
2443 /* Determine whether HELO/EHLO is required for this host. The requirement
2444 can be hard or soft. */
2446 helo_required = verify_check_host(&helo_verify_hosts) == OK;
2448 helo_verify = verify_check_host(&helo_try_verify_hosts) == OK;
2450 /* Determine whether this hosts is permitted to send syntactic junk
2451 after a HELO or EHLO command. */
2453 helo_accept_junk = verify_check_host(&helo_accept_junk_hosts) == OK;
2456 /* For batch SMTP input we are now done. */
2458 if (smtp_batched_input) return TRUE;
2460 #ifdef SUPPORT_PROXY
2461 /* If valid Proxy Protocol source is connecting, set up session.
2462 * Failure will not allow any SMTP function other than QUIT. */
2463 proxy_session = FALSE;
2464 proxy_session_failed = FALSE;
2465 if (check_proxy_protocol_host())
2466 if (!setup_proxy_protocol_host())
2468 proxy_session_failed = TRUE;
2470 debug_printf("Failure to extract proxied host, only QUIT allowed\n");
2474 sender_host_name = NULL;
2475 (void)host_name_lookup();
2476 host_build_sender_fullhost();
2480 /* Run the ACL if it exists */
2483 if (acl_smtp_connect)
2486 if ((rc = acl_check(ACL_WHERE_CONNECT, NULL, acl_smtp_connect, &user_msg,
2489 (void) smtp_handle_acl_fail(ACL_WHERE_CONNECT, rc, user_msg, log_msg);
2494 /* Output the initial message for a two-way SMTP connection. It may contain
2495 newlines, which then cause a multi-line response to be given. */
2497 code = US"220"; /* Default status code */
2498 esc = US""; /* Default extended status code */
2499 esclen = 0; /* Length of esc */
2503 if (!(s = expand_string(smtp_banner)))
2504 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "Expansion of \"%s\" (smtp_banner) "
2505 "failed: %s", smtp_banner, expand_string_message);
2511 smtp_message_code(&code, &codelen, &s, NULL, TRUE);
2515 esclen = codelen - 4;
2519 /* Remove any terminating newlines; might as well remove trailing space too */
2522 while (p > s && isspace(p[-1])) p--;
2525 /* It seems that CC:Mail is braindead, and assumes that the greeting message
2526 is all contained in a single IP packet. The original code wrote out the
2527 greeting using several calls to fprint/fputc, and on busy servers this could
2528 cause it to be split over more than one packet - which caused CC:Mail to fall
2529 over when it got the second part of the greeting after sending its first
2530 command. Sigh. To try to avoid this, build the complete greeting message
2531 first, and output it in one fell swoop. This gives a better chance of it
2532 ending up as a single packet. */
2534 ss = store_get(size);
2538 do /* At least once, in case we have an empty string */
2541 uschar *linebreak = Ustrchr(p, '\n');
2542 ss = string_catn(ss, &size, &ptr, code, 3);
2543 if (linebreak == NULL)
2546 ss = string_catn(ss, &size, &ptr, US" ", 1);
2550 len = linebreak - p;
2551 ss = string_catn(ss, &size, &ptr, US"-", 1);
2553 ss = string_catn(ss, &size, &ptr, esc, esclen);
2554 ss = string_catn(ss, &size, &ptr, p, len);
2555 ss = string_catn(ss, &size, &ptr, US"\r\n", 2);
2557 if (linebreak != NULL) p++;
2561 ss[ptr] = 0; /* string_cat leaves room for this */
2563 /* Before we write the banner, check that there is no input pending, unless
2564 this synchronisation check is disabled. */
2568 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP protocol "
2569 "synchronization error (input sent without waiting for greeting): "
2570 "rejected connection from %s input=\"%s\"", host_and_ident(TRUE),
2571 string_printing(smtp_inptr));
2572 smtp_printf("554 SMTP synchronization error\r\n");
2576 /* Now output the banner */
2578 smtp_printf("%s", ss);
2586 /*************************************************
2587 * Handle SMTP syntax and protocol errors *
2588 *************************************************/
2590 /* Write to the log for SMTP syntax errors in incoming commands, if configured
2591 to do so. Then transmit the error response. The return value depends on the
2592 number of syntax and protocol errors in this SMTP session.
2595 type error type, given as a log flag bit
2596 code response code; <= 0 means don't send a response
2597 data data to reflect in the response (can be NULL)
2598 errmess the error message
2600 Returns: -1 limit of syntax/protocol errors NOT exceeded
2601 +1 limit of syntax/protocol errors IS exceeded
2603 These values fit in with the values of the "done" variable in the main
2604 processing loop in smtp_setup_msg(). */
2607 synprot_error(int type, int code, uschar *data, uschar *errmess)
2611 log_write(type, LOG_MAIN, "SMTP %s error in \"%s\" %s %s",
2612 (type == L_smtp_syntax_error)? "syntax" : "protocol",
2613 string_printing(smtp_cmd_buffer), host_and_ident(TRUE), errmess);
2615 if (++synprot_error_count > smtp_max_synprot_errors)
2618 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
2619 "syntax or protocol errors (last command was \"%s\")",
2620 host_and_ident(FALSE), string_printing(smtp_cmd_buffer));
2625 smtp_printf("%d%c%s%s%s\r\n", code, (yield == 1)? '-' : ' ',
2626 (data == NULL)? US"" : data, (data == NULL)? US"" : US": ", errmess);
2628 smtp_printf("%d Too many syntax or protocol errors\r\n", code);
2637 /*************************************************
2638 * Log incomplete transactions *
2639 *************************************************/
2641 /* This function is called after a transaction has been aborted by RSET, QUIT,
2642 connection drops or other errors. It logs the envelope information received
2643 so far in order to preserve address verification attempts.
2645 Argument: string to indicate what aborted the transaction
2650 incomplete_transaction_log(uschar *what)
2652 if (sender_address == NULL || /* No transaction in progress */
2653 !LOGGING(smtp_incomplete_transaction))
2656 /* Build list of recipients for logging */
2658 if (recipients_count > 0)
2661 raw_recipients = store_get(recipients_count * sizeof(uschar *));
2662 for (i = 0; i < recipients_count; i++)
2663 raw_recipients[i] = recipients_list[i].address;
2664 raw_recipients_count = recipients_count;
2667 log_write(L_smtp_incomplete_transaction, LOG_MAIN|LOG_SENDER|LOG_RECIPIENTS,
2668 "%s incomplete transaction (%s)", host_and_ident(TRUE), what);
2674 /*************************************************
2675 * Send SMTP response, possibly multiline *
2676 *************************************************/
2678 /* There are, it seems, broken clients out there that cannot handle multiline
2679 responses. If no_multiline_responses is TRUE (it can be set from an ACL), we
2680 output nothing for non-final calls, and only the first line for anything else.
2683 code SMTP code, may involve extended status codes
2684 codelen length of smtp code; if > 4 there's an ESC
2685 final FALSE if the last line isn't the final line
2686 msg message text, possibly containing newlines
2692 smtp_respond(uschar* code, int codelen, BOOL final, uschar *msg)
2697 if (!final && no_multiline_responses) return;
2702 esclen = codelen - 4;
2705 /* If this is the first output for a (non-batch) RCPT command, see if all RCPTs
2706 have had the same. Note: this code is also present in smtp_printf(). It would
2707 be tidier to have it only in one place, but when it was added, it was easier to
2708 do it that way, so as not to have to mess with the code for the RCPT command,
2709 which sometimes uses smtp_printf() and sometimes smtp_respond(). */
2711 if (rcpt_in_progress)
2713 if (rcpt_smtp_response == NULL)
2714 rcpt_smtp_response = string_copy(msg);
2715 else if (rcpt_smtp_response_same &&
2716 Ustrcmp(rcpt_smtp_response, msg) != 0)
2717 rcpt_smtp_response_same = FALSE;
2718 rcpt_in_progress = FALSE;
2721 /* Not output the message, splitting it up into multiple lines if necessary. */
2725 uschar *nl = Ustrchr(msg, '\n');
2728 smtp_printf("%.3s%c%.*s%s\r\n", code, final? ' ':'-', esclen, esc, msg);
2731 else if (nl[1] == 0 || no_multiline_responses)
2733 smtp_printf("%.3s%c%.*s%.*s\r\n", code, final? ' ':'-', esclen, esc,
2734 (int)(nl - msg), msg);
2739 smtp_printf("%.3s-%.*s%.*s\r\n", code, esclen, esc, (int)(nl - msg), msg);
2741 while (isspace(*msg)) msg++;
2749 /*************************************************
2750 * Parse user SMTP message *
2751 *************************************************/
2753 /* This function allows for user messages overriding the response code details
2754 by providing a suitable response code string at the start of the message
2755 user_msg. Check the message for starting with a response code and optionally an
2756 extended status code. If found, check that the first digit is valid, and if so,
2757 change the code pointer and length to use the replacement. An invalid code
2758 causes a panic log; in this case, if the log messages is the same as the user
2759 message, we must also adjust the value of the log message to show the code that
2760 is actually going to be used (the original one).
2762 This function is global because it is called from receive.c as well as within
2765 Note that the code length returned includes the terminating whitespace
2766 character, which is always included in the regex match.
2769 code SMTP code, may involve extended status codes
2770 codelen length of smtp code; if > 4 there's an ESC
2772 log_msg optional log message, to be adjusted with the new SMTP code
2773 check_valid if true, verify the response code
2779 smtp_message_code(uschar **code, int *codelen, uschar **msg, uschar **log_msg,
2785 if (!msg || !*msg) return;
2787 if ((n = pcre_exec(regex_smtp_code, NULL, CS *msg, Ustrlen(*msg), 0,
2788 PCRE_EOPT, ovector, sizeof(ovector)/sizeof(int))) < 0) return;
2790 if (check_valid && (*msg)[0] != (*code)[0])
2792 log_write(0, LOG_MAIN|LOG_PANIC, "configured error code starts with "
2793 "incorrect digit (expected %c) in \"%s\"", (*code)[0], *msg);
2794 if (log_msg != NULL && *log_msg == *msg)
2795 *log_msg = string_sprintf("%s %s", *code, *log_msg + ovector[1]);
2800 *codelen = ovector[1]; /* Includes final space */
2802 *msg += ovector[1]; /* Chop the code off the message */
2809 /*************************************************
2810 * Handle an ACL failure *
2811 *************************************************/
2813 /* This function is called when acl_check() fails. As well as calls from within
2814 this module, it is called from receive.c for an ACL after DATA. It sorts out
2815 logging the incident, and sets up the error response. A message containing
2816 newlines is turned into a multiline SMTP response, but for logging, only the
2819 There's a table of default permanent failure response codes to use in
2820 globals.c, along with the table of names. VFRY is special. Despite RFC1123 it
2821 defaults disabled in Exim. However, discussion in connection with RFC 821bis
2822 (aka RFC 2821) has concluded that the response should be 252 in the disabled
2823 state, because there are broken clients that try VRFY before RCPT. A 5xx
2824 response should be given only when the address is positively known to be
2825 undeliverable. Sigh. We return 252 if there is no VRFY ACL or it provides
2826 no explicit code, but if there is one we let it know best.
2827 Also, for ETRN, 458 is given on refusal, and for AUTH, 503.
2829 From Exim 4.63, it is possible to override the response code details by
2830 providing a suitable response code string at the start of the message provided
2831 in user_msg. The code's first digit is checked for validity.
2834 where where the ACL was called from
2836 user_msg a message that can be included in an SMTP response
2837 log_msg a message for logging
2839 Returns: 0 in most cases
2840 2 if the failure code was FAIL_DROP, in which case the
2841 SMTP connection should be dropped (this value fits with the
2842 "done" variable in smtp_setup_msg() below)
2846 smtp_handle_acl_fail(int where, int rc, uschar *user_msg, uschar *log_msg)
2848 BOOL drop = rc == FAIL_DROP;
2852 uschar *sender_info = US"";
2854 #ifdef WITH_CONTENT_SCAN
2855 where == ACL_WHERE_MIME ? US"during MIME ACL checks" :
2857 where == ACL_WHERE_PREDATA ? US"DATA" :
2858 where == ACL_WHERE_DATA ? US"after DATA" :
2859 #ifndef DISABLE_PRDR
2860 where == ACL_WHERE_PRDR ? US"after DATA PRDR" :
2863 string_sprintf("%s %s", acl_wherenames[where], smtp_cmd_data) :
2864 string_sprintf("%s in \"connect\" ACL", acl_wherenames[where]);
2866 if (drop) rc = FAIL;
2868 /* Set the default SMTP code, and allow a user message to change it. */
2870 smtp_code = rc == FAIL ? acl_wherecodes[where] : US"451";
2871 smtp_message_code(&smtp_code, &codelen, &user_msg, &log_msg,
2872 where != ACL_WHERE_VRFY);
2874 /* We used to have sender_address here; however, there was a bug that was not
2875 updating sender_address after a rewrite during a verify. When this bug was
2876 fixed, sender_address at this point became the rewritten address. I'm not sure
2877 this is what should be logged, so I've changed to logging the unrewritten
2878 address to retain backward compatibility. */
2880 #ifndef WITH_CONTENT_SCAN
2881 if (where == ACL_WHERE_RCPT || where == ACL_WHERE_DATA)
2883 if (where == ACL_WHERE_RCPT || where == ACL_WHERE_DATA || where == ACL_WHERE_MIME)
2886 sender_info = string_sprintf("F=<%s>%s%s%s%s ",
2887 sender_address_unrewritten ? sender_address_unrewritten : sender_address,
2888 sender_host_authenticated ? US" A=" : US"",
2889 sender_host_authenticated ? sender_host_authenticated : US"",
2890 sender_host_authenticated && authenticated_id ? US":" : US"",
2891 sender_host_authenticated && authenticated_id ? authenticated_id : US""
2895 /* If there's been a sender verification failure with a specific message, and
2896 we have not sent a response about it yet, do so now, as a preliminary line for
2897 failures, but not defers. However, always log it for defer, and log it for fail
2898 unless the sender_verify_fail log selector has been turned off. */
2900 if (sender_verified_failed != NULL &&
2901 !testflag(sender_verified_failed, af_sverify_told))
2903 BOOL save_rcpt_in_progress = rcpt_in_progress;
2904 rcpt_in_progress = FALSE; /* So as not to treat these as the error */
2906 setflag(sender_verified_failed, af_sverify_told);
2908 if (rc != FAIL || LOGGING(sender_verify_fail))
2909 log_write(0, LOG_MAIN|LOG_REJECT, "%s sender verify %s for <%s>%s",
2910 host_and_ident(TRUE),
2911 ((sender_verified_failed->special_action & 255) == DEFER)? "defer":"fail",
2912 sender_verified_failed->address,
2913 (sender_verified_failed->message == NULL)? US"" :
2914 string_sprintf(": %s", sender_verified_failed->message));
2916 if (rc == FAIL && sender_verified_failed->user_message != NULL)
2917 smtp_respond(smtp_code, codelen, FALSE, string_sprintf(
2918 testflag(sender_verified_failed, af_verify_pmfail)?
2919 "Postmaster verification failed while checking <%s>\n%s\n"
2920 "Several RFCs state that you are required to have a postmaster\n"
2921 "mailbox for each mail domain. This host does not accept mail\n"
2922 "from domains whose servers reject the postmaster address."
2924 testflag(sender_verified_failed, af_verify_nsfail)?
2925 "Callback setup failed while verifying <%s>\n%s\n"
2926 "The initial connection, or a HELO or MAIL FROM:<> command was\n"
2927 "rejected. Refusing MAIL FROM:<> does not help fight spam, disregards\n"
2928 "RFC requirements, and stops you from receiving standard bounce\n"
2929 "messages. This host does not accept mail from domains whose servers\n"
2932 "Verification failed for <%s>\n%s",
2933 sender_verified_failed->address,
2934 sender_verified_failed->user_message));
2936 rcpt_in_progress = save_rcpt_in_progress;
2939 /* Sort out text for logging */
2941 log_msg = log_msg ? string_sprintf(": %s", log_msg) : US"";
2942 if ((lognl = Ustrchr(log_msg, '\n'))) *lognl = 0;
2944 /* Send permanent failure response to the command, but the code used isn't
2945 always a 5xx one - see comments at the start of this function. If the original
2946 rc was FAIL_DROP we drop the connection and yield 2. */
2949 smtp_respond(smtp_code, codelen, TRUE,
2950 user_msg ? user_msg : US"Administrative prohibition");
2952 /* Send temporary failure response to the command. Don't give any details,
2953 unless acl_temp_details is set. This is TRUE for a callout defer, a "defer"
2954 verb, and for a header verify when smtp_return_error_details is set.
2956 This conditional logic is all somewhat of a mess because of the odd
2957 interactions between temp_details and return_error_details. One day it should
2958 be re-implemented in a tidier fashion. */
2961 if (acl_temp_details && user_msg)
2963 if ( smtp_return_error_details
2964 && sender_verified_failed
2965 && sender_verified_failed->message
2967 smtp_respond(smtp_code, codelen, FALSE, sender_verified_failed->message);
2969 smtp_respond(smtp_code, codelen, TRUE, user_msg);
2972 smtp_respond(smtp_code, codelen, TRUE,
2973 US"Temporary local problem - please try later");
2975 /* Log the incident to the logs that are specified by log_reject_target
2976 (default main, reject). This can be empty to suppress logging of rejections. If
2977 the connection is not forcibly to be dropped, return 0. Otherwise, log why it
2978 is closing if required and return 2. */
2980 if (log_reject_target != 0)
2983 uschar * tls = s_tlslog(NULL, NULL, NULL);
2984 if (!tls) tls = US"";
2986 uschar * tls = US"";
2988 log_write(where == ACL_WHERE_CONNECT ? L_connection_reject : 0,
2989 log_reject_target, "%s%s%s %s%srejected %s%s",
2990 LOGGING(dnssec) && sender_host_dnssec ? US" DS" : US"",
2991 host_and_ident(TRUE),
2994 rc == FAIL ? US"" : US"temporarily ",
2998 if (!drop) return 0;
3000 log_write(L_smtp_connection, LOG_MAIN, "%s closed by DROP in ACL",
3001 smtp_get_connection_info());
3003 /* Run the not-quit ACL, but without any custom messages. This should not be a
3004 problem, because we get here only if some other ACL has issued "drop", and
3005 in that case, *its* custom messages will have been used above. */
3007 smtp_notquit_exit(US"acl-drop", NULL, NULL);
3014 /*************************************************
3015 * Handle SMTP exit when QUIT is not given *
3016 *************************************************/
3018 /* This function provides a logging/statistics hook for when an SMTP connection
3019 is dropped on the floor or the other end goes away. It's a global function
3020 because it's called from receive.c as well as this module. As well as running
3021 the NOTQUIT ACL, if there is one, this function also outputs a final SMTP
3022 response, either with a custom message from the ACL, or using a default. There
3023 is one case, however, when no message is output - after "drop". In that case,
3024 the ACL that obeyed "drop" has already supplied the custom message, and NULL is
3025 passed to this function.
3027 In case things go wrong while processing this function, causing an error that
3028 may re-enter this funtion, there is a recursion check.
3031 reason What $smtp_notquit_reason will be set to in the ACL;
3032 if NULL, the ACL is not run
3033 code The error code to return as part of the response
3034 defaultrespond The default message if there's no user_msg
3040 smtp_notquit_exit(uschar *reason, uschar *code, uschar *defaultrespond, ...)
3043 uschar *user_msg = NULL;
3044 uschar *log_msg = NULL;
3046 /* Check for recursive acll */
3048 if (smtp_exit_function_called)
3050 log_write(0, LOG_PANIC, "smtp_notquit_exit() called more than once (%s)",
3054 smtp_exit_function_called = TRUE;
3056 /* Call the not-QUIT ACL, if there is one, unless no reason is given. */
3058 if (acl_smtp_notquit && reason)
3060 smtp_notquit_reason = reason;
3061 if ((rc = acl_check(ACL_WHERE_NOTQUIT, NULL, acl_smtp_notquit, &user_msg,
3062 &log_msg)) == ERROR)
3063 log_write(0, LOG_MAIN|LOG_PANIC, "ACL for not-QUIT returned ERROR: %s",
3067 /* Write an SMTP response if we are expected to give one. As the default
3068 responses are all internal, they should always fit in the buffer, but code a
3069 warning, just in case. Note that string_vformat() still leaves a complete
3070 string, even if it is incomplete. */
3072 if (code && defaultrespond)
3075 smtp_respond(code, 3, TRUE, user_msg);
3080 va_start(ap, defaultrespond);
3081 if (!string_vformat(buffer, sizeof(buffer), CS defaultrespond, ap))
3082 log_write(0, LOG_MAIN|LOG_PANIC, "string too large in smtp_notquit_exit()");
3083 smtp_printf("%s %s\r\n", code, buffer);
3093 /*************************************************
3094 * Verify HELO argument *
3095 *************************************************/
3097 /* This function is called if helo_verify_hosts or helo_try_verify_hosts is
3098 matched. It is also called from ACL processing if verify = helo is used and
3099 verification was not previously tried (i.e. helo_try_verify_hosts was not
3100 matched). The result of its processing is to set helo_verified and
3101 helo_verify_failed. These variables should both be FALSE for this function to
3104 Note that EHLO/HELO is legitimately allowed to quote an address literal. Allow
3105 for IPv6 ::ffff: literals.
3108 Returns: TRUE if testing was completed;
3109 FALSE on a temporary failure
3113 smtp_verify_helo(void)
3117 HDEBUG(D_receive) debug_printf("verifying EHLO/HELO argument \"%s\"\n",
3120 if (sender_helo_name == NULL)
3122 HDEBUG(D_receive) debug_printf("no EHLO/HELO command was issued\n");
3125 /* Deal with the case of -bs without an IP address */
3127 else if (sender_host_address == NULL)
3129 HDEBUG(D_receive) debug_printf("no client IP address: assume success\n");
3130 helo_verified = TRUE;
3133 /* Deal with the more common case when there is a sending IP address */
3135 else if (sender_helo_name[0] == '[')
3137 helo_verified = Ustrncmp(sender_helo_name+1, sender_host_address,
3138 Ustrlen(sender_host_address)) == 0;
3143 if (strncmpic(sender_host_address, US"::ffff:", 7) == 0)
3144 helo_verified = Ustrncmp(sender_helo_name + 1,
3145 sender_host_address + 7, Ustrlen(sender_host_address) - 7) == 0;
3150 { if (helo_verified) debug_printf("matched host address\n"); }
3153 /* Do a reverse lookup if one hasn't already given a positive or negative
3154 response. If that fails, or the name doesn't match, try checking with a forward
3159 if (sender_host_name == NULL && !host_lookup_failed)
3160 yield = host_name_lookup() != DEFER;
3162 /* If a host name is known, check it and all its aliases. */
3164 if (sender_host_name)
3165 if ((helo_verified = strcmpic(sender_host_name, sender_helo_name) == 0))
3167 sender_helo_dnssec = sender_host_dnssec;
3168 HDEBUG(D_receive) debug_printf("matched host name\n");
3172 uschar **aliases = sender_host_aliases;
3174 if ((helo_verified = strcmpic(*aliases++, sender_helo_name) == 0))
3176 sender_helo_dnssec = sender_host_dnssec;
3180 HDEBUG(D_receive) if (helo_verified)
3181 debug_printf("matched alias %s\n", *(--aliases));
3184 /* Final attempt: try a forward lookup of the helo name */
3193 h.name = sender_helo_name;
3200 HDEBUG(D_receive) debug_printf("getting IP address for %s\n",
3202 rc = host_find_bydns(&h, NULL, HOST_FIND_BY_A,
3203 NULL, NULL, NULL, &d, NULL, NULL);
3204 if (rc == HOST_FOUND || rc == HOST_FOUND_LOCAL)
3205 for (hh = &h; hh; hh = hh->next)
3206 if (Ustrcmp(hh->address, sender_host_address) == 0)
3208 helo_verified = TRUE;
3209 if (h.dnssec == DS_YES) sender_helo_dnssec = TRUE;
3212 debug_printf("IP address for %s matches calling address\n"
3213 "Forward DNS security status: %sverified\n",
3214 sender_helo_name, sender_helo_dnssec ? "" : "un");
3221 if (!helo_verified) helo_verify_failed = TRUE; /* We've tried ... */
3228 /*************************************************
3229 * Send user response message *
3230 *************************************************/
3232 /* This function is passed a default response code and a user message. It calls
3233 smtp_message_code() to check and possibly modify the response code, and then
3234 calls smtp_respond() to transmit the response. I put this into a function
3235 just to avoid a lot of repetition.
3238 code the response code
3239 user_msg the user message
3245 smtp_user_msg(uschar *code, uschar *user_msg)
3248 smtp_message_code(&code, &len, &user_msg, NULL, TRUE);
3249 smtp_respond(code, len, TRUE, user_msg);
3255 smtp_in_auth(auth_instance *au, uschar ** s, uschar ** ss)
3257 const uschar *set_id = NULL;
3260 /* Run the checking code, passing the remainder of the command line as
3261 data. Initials the $auth<n> variables as empty. Initialize $0 empty and set
3262 it as the only set numerical variable. The authenticator may set $auth<n>
3263 and also set other numeric variables. The $auth<n> variables are preferred
3264 nowadays; the numerical variables remain for backwards compatibility.
3266 Afterwards, have a go at expanding the set_id string, even if
3267 authentication failed - for bad passwords it can be useful to log the
3268 userid. On success, require set_id to expand and exist, and put it in
3269 authenticated_id. Save this in permanent store, as the working store gets
3270 reset at HELO, RSET, etc. */
3272 for (i = 0; i < AUTH_VARS; i++) auth_vars[i] = NULL;
3274 expand_nlength[0] = 0; /* $0 contains nothing */
3276 rc = (au->info->servercode)(au, smtp_cmd_data);
3277 if (au->set_id) set_id = expand_string(au->set_id);
3278 expand_nmax = -1; /* Reset numeric variables */
3279 for (i = 0; i < AUTH_VARS; i++) auth_vars[i] = NULL; /* Reset $auth<n> */
3281 /* The value of authenticated_id is stored in the spool file and printed in
3282 log lines. It must not contain binary zeros or newline characters. In
3283 normal use, it never will, but when playing around or testing, this error
3284 can (did) happen. To guard against this, ensure that the id contains only
3285 printing characters. */
3287 if (set_id) set_id = string_printing(set_id);
3289 /* For the non-OK cases, set up additional logging data if set_id
3293 set_id = set_id && *set_id
3294 ? string_sprintf(" (set_id=%s)", set_id) : US"";
3296 /* Switch on the result */
3301 if (!au->set_id || set_id) /* Complete success */
3303 if (set_id) authenticated_id = string_copy_malloc(set_id);
3304 sender_host_authenticated = au->name;
3305 authentication_failed = FALSE;
3306 authenticated_fail_id = NULL; /* Impossible to already be set? */
3309 (sender_host_address ? protocols : protocols_local)
3310 [pextend + pauthed + (tls_in.active >= 0 ? pcrpted:0)];
3311 *s = *ss = US"235 Authentication succeeded";
3312 authenticated_by = au;
3316 /* Authentication succeeded, but we failed to expand the set_id string.
3317 Treat this as a temporary error. */
3319 auth_defer_msg = expand_string_message;
3323 if (set_id) authenticated_fail_id = string_copy_malloc(set_id);
3324 *s = string_sprintf("435 Unable to authenticate at present%s",
3325 auth_defer_user_msg);
3326 *ss = string_sprintf("435 Unable to authenticate at present%s: %s",
3327 set_id, auth_defer_msg);
3331 *s = *ss = US"501 Invalid base64 data";
3335 *s = *ss = US"501 Authentication cancelled";
3339 *s = *ss = US"553 Initial data not expected";
3343 if (set_id) authenticated_fail_id = string_copy_malloc(set_id);
3344 *s = US"535 Incorrect authentication data";
3345 *ss = string_sprintf("535 Incorrect authentication data%s", set_id);
3349 if (set_id) authenticated_fail_id = string_copy_malloc(set_id);
3350 *s = US"435 Internal error";
3351 *ss = string_sprintf("435 Internal error%s: return %d from authentication "
3352 "check", set_id, rc);
3364 qualify_recipient(uschar ** recipient, uschar * smtp_cmd_data, uschar * tag)
3367 if (allow_unqualified_recipient || strcmpic(*recipient, US"postmaster") == 0)
3369 DEBUG(D_receive) debug_printf("unqualified address %s accepted\n",
3371 rd = Ustrlen(recipient) + 1;
3372 *recipient = rewrite_address_qualify(*recipient, TRUE);
3375 smtp_printf("501 %s: recipient address must contain a domain\r\n",
3377 log_write(L_smtp_syntax_error,
3378 LOG_MAIN|LOG_REJECT, "unqualified %s rejected: <%s> %s%s",
3379 tag, *recipient, host_and_ident(TRUE), host_lookup_msg);
3387 smtp_quit_handler(uschar ** user_msgp, uschar ** log_msgp)
3390 incomplete_transaction_log(US"QUIT");
3393 int rc = acl_check(ACL_WHERE_QUIT, NULL, acl_smtp_quit, user_msgp, log_msgp);
3395 log_write(0, LOG_MAIN|LOG_PANIC, "ACL for QUIT returned ERROR: %s",
3399 smtp_respond(US"221", 3, TRUE, *user_msgp);
3401 smtp_printf("221 %s closing connection\r\n", smtp_active_hostname);
3404 tls_close(TRUE, TRUE);
3407 log_write(L_smtp_connection, LOG_MAIN, "%s closed by QUIT",
3408 smtp_get_connection_info());
3413 smtp_rset_handler(void)
3416 incomplete_transaction_log(US"RSET");
3417 smtp_printf("250 Reset OK\r\n");
3418 cmd_list[CMD_LIST_RSET].is_mail_cmd = FALSE;
3423 /*************************************************
3424 * Initialize for SMTP incoming message *
3425 *************************************************/
3427 /* This function conducts the initial dialogue at the start of an incoming SMTP
3428 message, and builds a list of recipients. However, if the incoming message
3429 is part of a batch (-bS option) a separate function is called since it would
3430 be messy having tests splattered about all over this function. This function
3431 therefore handles the case where interaction is occurring. The input and output
3432 files are set up in smtp_in and smtp_out.
3434 The global recipients_list is set to point to a vector of recipient_item
3435 blocks, whose number is given by recipients_count. This is extended by the
3436 receive_add_recipient() function. The global variable sender_address is set to
3437 the sender's address. The yield is +1 if a message has been successfully
3438 started, 0 if a QUIT command was encountered or the connection was refused from
3439 the particular host, or -1 if the connection was lost.
3443 Returns: > 0 message successfully started (reached DATA)
3444 = 0 QUIT read or end of file reached or call refused
3449 smtp_setup_msg(void)
3452 BOOL toomany = FALSE;
3453 BOOL discarded = FALSE;
3454 BOOL last_was_rej_mail = FALSE;
3455 BOOL last_was_rcpt = FALSE;
3456 void *reset_point = store_get(0);
3458 DEBUG(D_receive) debug_printf("smtp_setup_msg entered\n");
3460 /* Reset for start of new message. We allow one RSET not to be counted as a
3461 nonmail command, for those MTAs that insist on sending it between every
3462 message. Ditto for EHLO/HELO and for STARTTLS, to allow for going in and out of
3463 TLS between messages (an Exim client may do this if it has messages queued up
3464 for the host). Note: we do NOT reset AUTH at this point. */
3466 smtp_reset(reset_point);
3467 message_ended = END_NOTSTARTED;
3469 chunking_state = chunking_offered ? CHUNKING_OFFERED : CHUNKING_NOT_OFFERED;
3471 cmd_list[CMD_LIST_RSET].is_mail_cmd = TRUE;
3472 cmd_list[CMD_LIST_HELO].is_mail_cmd = TRUE;
3473 cmd_list[CMD_LIST_EHLO].is_mail_cmd = TRUE;
3475 cmd_list[CMD_LIST_STARTTLS].is_mail_cmd = TRUE;
3476 cmd_list[CMD_LIST_TLS_AUTH].is_mail_cmd = TRUE;
3479 /* Set the local signal handler for SIGTERM - it tries to end off tidily */
3481 os_non_restarting_signal(SIGTERM, command_sigterm_handler);
3483 /* Batched SMTP is handled in a different function. */
3485 if (smtp_batched_input) return smtp_setup_batch_msg();
3487 /* Deal with SMTP commands. This loop is exited by setting done to a POSITIVE
3488 value. The values are 2 larger than the required yield of the function. */
3492 const uschar **argv;
3493 uschar *etrn_command;
3494 uschar *etrn_serialize_key;
3496 uschar *log_msg, *smtp_code;
3497 uschar *user_msg = NULL;
3498 uschar *recipient = NULL;
3499 uschar *hello = NULL;
3501 BOOL was_rej_mail = FALSE;
3502 BOOL was_rcpt = FALSE;
3503 void (*oldsignal)(int);
3505 int start, end, sender_domain, recipient_domain;
3509 uschar *orcpt = NULL;
3513 /* Check once per STARTTLS or SSL-on-connect for a TLS AUTH */
3514 if ( tls_in.active >= 0
3516 && tls_in.certificate_verified
3517 && cmd_list[CMD_LIST_TLS_AUTH].is_mail_cmd
3520 cmd_list[CMD_LIST_TLS_AUTH].is_mail_cmd = FALSE;
3522 && (rc = acl_check(ACL_WHERE_AUTH, NULL, acl_smtp_auth,
3523 &user_msg, &log_msg)) != OK
3526 done = smtp_handle_acl_fail(ACL_WHERE_AUTH, rc, user_msg, log_msg);
3530 for (au = auths; au; au = au->next)
3531 if (strcmpic(US"tls", au->driver_name) == 0)
3533 smtp_cmd_data = NULL;
3535 if (smtp_in_auth(au, &s, &ss) == OK)
3536 { DEBUG(D_auth) debug_printf("tls auth succeeded\n"); }
3538 { DEBUG(D_auth) debug_printf("tls auth not succeeded\n"); }
3545 if (smtp_in) /* Avoid pure-ACKs while in cmd pingpong phase */
3546 (void) setsockopt(fileno(smtp_in), IPPROTO_TCP, TCP_QUICKACK,
3547 US &off, sizeof(off));
3550 switch(smtp_read_command(TRUE))
3552 /* The AUTH command is not permitted to occur inside a transaction, and may
3553 occur successfully only once per connection. Actually, that isn't quite
3554 true. When TLS is started, all previous information about a connection must
3555 be discarded, so a new AUTH is permitted at that time.
3557 AUTH may only be used when it has been advertised. However, it seems that
3558 there are clients that send AUTH when it hasn't been advertised, some of
3559 them even doing this after HELO. And there are MTAs that accept this. Sigh.
3560 So there's a get-out that allows this to happen.
3562 AUTH is initially labelled as a "nonmail command" so that one occurrence
3563 doesn't get counted. We change the label here so that multiple failing
3564 AUTHS will eventually hit the nonmail threshold. */
3568 authentication_failed = TRUE;
3569 cmd_list[CMD_LIST_AUTH].is_mail_cmd = FALSE;
3571 if (!auth_advertised && !allow_auth_unadvertised)
3573 done = synprot_error(L_smtp_protocol_error, 503, NULL,
3574 US"AUTH command used when not advertised");
3577 if (sender_host_authenticated)
3579 done = synprot_error(L_smtp_protocol_error, 503, NULL,
3580 US"already authenticated");
3585 done = synprot_error(L_smtp_protocol_error, 503, NULL,
3586 US"not permitted in mail transaction");
3593 && (rc = acl_check(ACL_WHERE_AUTH, NULL, acl_smtp_auth,
3594 &user_msg, &log_msg)) != OK
3597 done = smtp_handle_acl_fail(ACL_WHERE_AUTH, rc, user_msg, log_msg);
3601 /* Find the name of the requested authentication mechanism. */
3604 while ((c = *smtp_cmd_data) != 0 && !isspace(c))
3606 if (!isalnum(c) && c != '-' && c != '_')
3608 done = synprot_error(L_smtp_syntax_error, 501, NULL,
3609 US"invalid character in authentication mechanism name");
3615 /* If not at the end of the line, we must be at white space. Terminate the
3616 name and move the pointer on to any data that may be present. */
3618 if (*smtp_cmd_data != 0)
3620 *smtp_cmd_data++ = 0;
3621 while (isspace(*smtp_cmd_data)) smtp_cmd_data++;
3624 /* Search for an authentication mechanism which is configured for use
3625 as a server and which has been advertised (unless, sigh, allow_auth_
3626 unadvertised is set). */
3628 for (au = auths; au; au = au->next)
3629 if (strcmpic(s, au->public_name) == 0 && au->server &&
3630 (au->advertised || allow_auth_unadvertised))
3635 c = smtp_in_auth(au, &s, &ss);
3637 smtp_printf("%s\r\n", s);
3639 log_write(0, LOG_MAIN|LOG_REJECT, "%s authenticator failed for %s: %s",
3640 au->name, host_and_ident(FALSE), ss);
3643 done = synprot_error(L_smtp_protocol_error, 504, NULL,
3644 string_sprintf("%s authentication mechanism not supported", s));
3646 break; /* AUTH_CMD */
3648 /* The HELO/EHLO commands are permitted to appear in the middle of a
3649 session as well as at the beginning. They have the effect of a reset in
3650 addition to their other functions. Their absence at the start cannot be
3651 taken to be an error.
3655 If the EHLO command is not acceptable to the SMTP server, 501, 500,
3656 or 502 failure replies MUST be returned as appropriate. The SMTP
3657 server MUST stay in the same state after transmitting these replies
3658 that it was in before the EHLO was received.
3660 Therefore, we do not do the reset until after checking the command for
3661 acceptability. This change was made for Exim release 4.11. Previously
3662 it did the reset first. */
3675 HELO_EHLO: /* Common code for HELO and EHLO */
3676 cmd_list[CMD_LIST_HELO].is_mail_cmd = FALSE;
3677 cmd_list[CMD_LIST_EHLO].is_mail_cmd = FALSE;
3679 /* Reject the HELO if its argument was invalid or non-existent. A
3680 successful check causes the argument to be saved in malloc store. */
3682 if (!check_helo(smtp_cmd_data))
3684 smtp_printf("501 Syntactically invalid %s argument(s)\r\n", hello);
3686 log_write(0, LOG_MAIN|LOG_REJECT, "rejected %s from %s: syntactically "
3687 "invalid argument(s): %s", hello, host_and_ident(FALSE),
3688 (*smtp_cmd_argument == 0)? US"(no argument given)" :
3689 string_printing(smtp_cmd_argument));
3691 if (++synprot_error_count > smtp_max_synprot_errors)
3693 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
3694 "syntax or protocol errors (last command was \"%s\")",
3695 host_and_ident(FALSE), string_printing(smtp_cmd_buffer));
3702 /* If sender_host_unknown is true, we have got here via the -bs interface,
3703 not called from inetd. Otherwise, we are running an IP connection and the
3704 host address will be set. If the helo name is the primary name of this
3705 host and we haven't done a reverse lookup, force one now. If helo_required
3706 is set, ensure that the HELO name matches the actual host. If helo_verify
3707 is set, do the same check, but softly. */
3709 if (!sender_host_unknown)
3711 BOOL old_helo_verified = helo_verified;
3712 uschar *p = smtp_cmd_data;
3714 while (*p != 0 && !isspace(*p)) { *p = tolower(*p); p++; }
3717 /* Force a reverse lookup if HELO quoted something in helo_lookup_domains
3718 because otherwise the log can be confusing. */
3720 if (sender_host_name == NULL &&
3721 (deliver_domain = sender_helo_name, /* set $domain */
3722 match_isinlist(sender_helo_name, CUSS &helo_lookup_domains, 0,
3723 &domainlist_anchor, NULL, MCL_DOMAIN, TRUE, NULL)) == OK)
3724 (void)host_name_lookup();
3726 /* Rebuild the fullhost info to include the HELO name (and the real name
3727 if it was looked up.) */
3729 host_build_sender_fullhost(); /* Rebuild */
3730 set_process_info("handling%s incoming connection from %s",
3731 (tls_in.active >= 0)? " TLS" : "", host_and_ident(FALSE));
3733 /* Verify if configured. This doesn't give much security, but it does
3734 make some people happy to be able to do it. If helo_required is set,
3735 (host matches helo_verify_hosts) failure forces rejection. If helo_verify
3736 is set (host matches helo_try_verify_hosts), it does not. This is perhaps
3737 now obsolescent, since the verification can now be requested selectively
3740 helo_verified = helo_verify_failed = sender_helo_dnssec = FALSE;
3741 if (helo_required || helo_verify)
3743 BOOL tempfail = !smtp_verify_helo();
3748 smtp_printf("%d %s argument does not match calling host\r\n",
3749 tempfail? 451 : 550, hello);
3750 log_write(0, LOG_MAIN|LOG_REJECT, "%srejected \"%s %s\" from %s",
3751 tempfail? "temporarily " : "",
3752 hello, sender_helo_name, host_and_ident(FALSE));
3753 helo_verified = old_helo_verified;
3754 break; /* End of HELO/EHLO processing */
3756 HDEBUG(D_all) debug_printf("%s verification failed but host is in "
3757 "helo_try_verify_hosts\n", hello);
3762 #ifdef EXPERIMENTAL_SPF
3763 /* set up SPF context */
3764 spf_init(sender_helo_name, sender_host_address);
3767 /* Apply an ACL check if one is defined; afterwards, recheck
3768 synchronization in case the client started sending in a delay. */
3771 if ((rc = acl_check(ACL_WHERE_HELO, NULL, acl_smtp_helo,
3772 &user_msg, &log_msg)) != OK)
3774 done = smtp_handle_acl_fail(ACL_WHERE_HELO, rc, user_msg, log_msg);
3775 sender_helo_name = NULL;
3776 host_build_sender_fullhost(); /* Rebuild */
3779 else if (!check_sync()) goto SYNC_FAILURE;
3781 /* Generate an OK reply. The default string includes the ident if present,
3782 and also the IP address if present. Reflecting back the ident is intended
3783 as a deterrent to mail forgers. For maximum efficiency, and also because
3784 some broken systems expect each response to be in a single packet, arrange
3785 that the entire reply is sent in one write(). */
3787 auth_advertised = FALSE;
3788 pipelining_advertised = FALSE;
3790 tls_advertised = FALSE;
3792 dsn_advertised = FALSE;
3794 smtputf8_advertised = FALSE;
3797 smtp_code = US"250 "; /* Default response code plus space*/
3798 if (user_msg == NULL)
3800 s = string_sprintf("%.3s %s Hello %s%s%s",
3802 smtp_active_hostname,
3803 (sender_ident == NULL)? US"" : sender_ident,
3804 (sender_ident == NULL)? US"" : US" at ",
3805 (sender_host_name == NULL)? sender_helo_name : sender_host_name);
3810 if (sender_host_address != NULL)
3812 s = string_catn(s, &size, &ptr, US" [", 2);
3813 s = string_cat (s, &size, &ptr, sender_host_address);
3814 s = string_catn(s, &size, &ptr, US"]", 1);
3818 /* A user-supplied EHLO greeting may not contain more than one line. Note
3819 that the code returned by smtp_message_code() includes the terminating
3820 whitespace character. */
3826 smtp_message_code(&smtp_code, &codelen, &user_msg, NULL, TRUE);
3827 s = string_sprintf("%.*s%s", codelen, smtp_code, user_msg);
3828 if ((ss = strpbrk(CS s, "\r\n")) != NULL)
3830 log_write(0, LOG_MAIN|LOG_PANIC, "EHLO/HELO response must not contain "
3831 "newlines: message truncated: %s", string_printing(s));
3838 s = string_catn(s, &size, &ptr, US"\r\n", 2);
3840 /* If we received EHLO, we must create a multiline response which includes
3841 the functions supported. */
3847 /* I'm not entirely happy with this, as an MTA is supposed to check
3848 that it has enough room to accept a message of maximum size before
3849 it sends this. However, there seems little point in not sending it.
3850 The actual size check happens later at MAIL FROM time. By postponing it
3851 till then, VRFY and EXPN can be used after EHLO when space is short. */
3853 if (thismessage_size_limit > 0)
3855 sprintf(CS big_buffer, "%.3s-SIZE %d\r\n", smtp_code,
3856 thismessage_size_limit);
3857 s = string_cat(s, &size, &ptr, big_buffer);
3861 s = string_catn(s, &size, &ptr, smtp_code, 3);
3862 s = string_catn(s, &size, &ptr, US"-SIZE\r\n", 7);
3865 /* Exim does not do protocol conversion or data conversion. It is 8-bit
3866 clean; if it has an 8-bit character in its hand, it just sends it. It
3867 cannot therefore specify 8BITMIME and remain consistent with the RFCs.
3868 However, some users want this option simply in order to stop MUAs
3869 mangling messages that contain top-bit-set characters. It is therefore
3870 provided as an option. */
3872 if (accept_8bitmime)
3874 s = string_catn(s, &size, &ptr, smtp_code, 3);
3875 s = string_catn(s, &size, &ptr, US"-8BITMIME\r\n", 11);
3878 /* Advertise DSN support if configured to do so. */
3879 if (verify_check_host(&dsn_advertise_hosts) != FAIL)
3881 s = string_catn(s, &size, &ptr, smtp_code, 3);
3882 s = string_catn(s, &size, &ptr, US"-DSN\r\n", 6);
3883 dsn_advertised = TRUE;
3886 /* Advertise ETRN if there's an ACL checking whether a host is
3887 permitted to issue it; a check is made when any host actually tries. */
3889 if (acl_smtp_etrn != NULL)
3891 s = string_catn(s, &size, &ptr, smtp_code, 3);
3892 s = string_catn(s, &size, &ptr, US"-ETRN\r\n", 7);
3895 /* Advertise EXPN if there's an ACL checking whether a host is
3896 permitted to issue it; a check is made when any host actually tries. */
3898 if (acl_smtp_expn != NULL)
3900 s = string_catn(s, &size, &ptr, smtp_code, 3);
3901 s = string_catn(s, &size, &ptr, US"-EXPN\r\n", 7);
3904 /* Exim is quite happy with pipelining, so let the other end know that
3905 it is safe to use it, unless advertising is disabled. */
3907 if (pipelining_enable &&
3908 verify_check_host(&pipelining_advertise_hosts) == OK)
3910 s = string_catn(s, &size, &ptr, smtp_code, 3);
3911 s = string_catn(s, &size, &ptr, US"-PIPELINING\r\n", 13);
3912 sync_cmd_limit = NON_SYNC_CMD_PIPELINING;
3913 pipelining_advertised = TRUE;
3917 /* If any server authentication mechanisms are configured, advertise
3918 them if the current host is in auth_advertise_hosts. The problem with
3919 advertising always is that some clients then require users to
3920 authenticate (and aren't configurable otherwise) even though it may not
3921 be necessary (e.g. if the host is in host_accept_relay).
3923 RFC 2222 states that SASL mechanism names contain only upper case
3924 letters, so output the names in upper case, though we actually recognize
3925 them in either case in the AUTH command. */
3929 && !sender_host_authenticated
3931 && verify_check_host(&auth_advertise_hosts) == OK
3936 for (au = auths; au; au = au->next)
3937 if (au->server && (au->advertise_condition == NULL ||
3938 expand_check_condition(au->advertise_condition, au->name,
3939 US"authenticator")))
3944 s = string_catn(s, &size, &ptr, smtp_code, 3);
3945 s = string_catn(s, &size, &ptr, US"-AUTH", 5);
3947 auth_advertised = TRUE;
3950 s = string_catn(s, &size, &ptr, US" ", 1);
3951 s = string_cat (s, &size, &ptr, au->public_name);
3952 while (++saveptr < ptr) s[saveptr] = toupper(s[saveptr]);
3953 au->advertised = TRUE;
3956 au->advertised = FALSE;
3958 if (!first) s = string_catn(s, &size, &ptr, US"\r\n", 2);
3961 /* RFC 3030 CHUNKING */
3963 if (verify_check_host(&chunking_advertise_hosts) != FAIL)
3965 s = string_catn(s, &size, &ptr, smtp_code, 3);
3966 s = string_catn(s, &size, &ptr, US"-CHUNKING\r\n", 11);
3967 chunking_offered = TRUE;
3968 chunking_state = CHUNKING_OFFERED;
3971 /* Advertise TLS (Transport Level Security) aka SSL (Secure Socket Layer)
3972 if it has been included in the binary, and the host matches
3973 tls_advertise_hosts. We must *not* advertise if we are already in a
3974 secure connection. */
3977 if (tls_in.active < 0 &&
3978 verify_check_host(&tls_advertise_hosts) != FAIL)
3980 s = string_catn(s, &size, &ptr, smtp_code, 3);
3981 s = string_catn(s, &size, &ptr, US"-STARTTLS\r\n", 11);
3982 tls_advertised = TRUE;
3986 #ifndef DISABLE_PRDR
3987 /* Per Recipient Data Response, draft by Eric A. Hall extending RFC */
3990 s = string_catn(s, &size, &ptr, smtp_code, 3);
3991 s = string_catn(s, &size, &ptr, US"-PRDR\r\n", 7);
3996 if ( accept_8bitmime
3997 && verify_check_host(&smtputf8_advertise_hosts) != FAIL)
3999 s = string_catn(s, &size, &ptr, smtp_code, 3);
4000 s = string_catn(s, &size, &ptr, US"-SMTPUTF8\r\n", 11);
4001 smtputf8_advertised = TRUE;
4005 /* Finish off the multiline reply with one that is always available. */
4007 s = string_catn(s, &size, &ptr, smtp_code, 3);
4008 s = string_catn(s, &size, &ptr, US" HELP\r\n", 7);
4011 /* Terminate the string (for debug), write it, and note that HELO/EHLO
4017 if (tls_in.active >= 0) (void)tls_write(TRUE, s, ptr); else
4021 int i = fwrite(s, 1, ptr, smtp_out); i = i; /* compiler quietening */
4026 while ((cr = Ustrchr(s, '\r')) != NULL) /* lose CRs */
4027 memmove(cr, cr + 1, (ptr--) - (cr - s));
4028 debug_printf("SMTP>> %s", s);
4032 /* Reset the protocol and the state, abandoning any previous message. */
4034 (sender_host_address ? protocols : protocols_local)
4036 ? pextend + (sender_host_authenticated ? pauthed : 0)
4038 + (tls_in.active >= 0 ? pcrpted : 0)
4040 smtp_reset(reset_point);
4042 break; /* HELO/EHLO */
4045 /* The MAIL command requires an address as an operand. All we do
4046 here is to parse it for syntactic correctness. The form "<>" is
4047 a special case which converts into an empty string. The start/end
4048 pointers in the original are not used further for this address, as
4049 it is the canonical extracted address which is all that is kept. */
4053 smtp_mailcmd_count++; /* Count for limit and ratelimit */
4054 was_rej_mail = TRUE; /* Reset if accepted */
4055 env_mail_type_t * mail_args; /* Sanity check & validate args */
4057 if (helo_required && !helo_seen)
4059 smtp_printf("503 HELO or EHLO required\r\n");
4060 log_write(0, LOG_MAIN|LOG_REJECT, "rejected MAIL from %s: no "
4061 "HELO/EHLO given", host_and_ident(FALSE));
4065 if (sender_address != NULL)
4067 done = synprot_error(L_smtp_protocol_error, 503, NULL,
4068 US"sender already given");
4072 if (smtp_cmd_data[0] == 0)
4074 done = synprot_error(L_smtp_protocol_error, 501, NULL,
4075 US"MAIL must have an address operand");
4079 /* Check to see if the limit for messages per connection would be
4080 exceeded by accepting further messages. */
4082 if (smtp_accept_max_per_connection > 0 &&
4083 smtp_mailcmd_count > smtp_accept_max_per_connection)
4085 smtp_printf("421 too many messages in this connection\r\n");
4086 log_write(0, LOG_MAIN|LOG_REJECT, "rejected MAIL command %s: too many "
4087 "messages in one connection", host_and_ident(TRUE));
4091 /* Reset for start of message - even if this is going to fail, we
4092 obviously need to throw away any previous data. */
4094 smtp_reset(reset_point);
4096 sender_data = recipient_data = NULL;
4098 /* Loop, checking for ESMTP additions to the MAIL FROM command. */
4102 uschar *name, *value, *end;
4103 unsigned long int size;
4104 BOOL arg_error = FALSE;
4106 if (!extract_option(&name, &value)) break;
4108 for (mail_args = env_mail_type_list;
4109 mail_args->value != ENV_MAIL_OPT_NULL;
4112 if (strcmpic(name, mail_args->name) == 0)
4114 if (mail_args->need_value && strcmpic(value, US"") == 0)
4117 switch(mail_args->value)
4119 /* Handle SIZE= by reading the value. We don't do the check till later,
4120 in order to be able to log the sender address on failure. */
4121 case ENV_MAIL_OPT_SIZE:
4122 if (((size = Ustrtoul(value, &end, 10)), *end == 0))
4124 if ((size == ULONG_MAX && errno == ERANGE) || size > INT_MAX)
4126 message_size = (int)size;
4132 /* If this session was initiated with EHLO and accept_8bitmime is set,
4133 Exim will have indicated that it supports the BODY=8BITMIME option. In
4134 fact, it does not support this according to the RFCs, in that it does not
4135 take any special action for forwarding messages containing 8-bit
4136 characters. That is why accept_8bitmime is not the default setting, but
4137 some sites want the action that is provided. We recognize both "8BITMIME"
4138 and "7BIT" as body types, but take no action. */
4139 case ENV_MAIL_OPT_BODY:
4140 if (accept_8bitmime) {
4141 if (strcmpic(value, US"8BITMIME") == 0)
4143 else if (strcmpic(value, US"7BIT") == 0)
4148 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4149 US"invalid data for BODY");
4152 DEBUG(D_receive) debug_printf("8BITMIME: %d\n", body_8bitmime);
4158 /* Handle the two DSN options, but only if configured to do so (which
4159 will have caused "DSN" to be given in the EHLO response). The code itself
4160 is included only if configured in at build time. */
4162 case ENV_MAIL_OPT_RET:
4165 /* Check if RET has already been set */
4168 synprot_error(L_smtp_syntax_error, 501, NULL,
4169 US"RET can be specified once only");
4172 dsn_ret = strcmpic(value, US"HDRS") == 0
4174 : strcmpic(value, US"FULL") == 0
4177 DEBUG(D_receive) debug_printf("DSN_RET: %d\n", dsn_ret);
4178 /* Check for invalid invalid value, and exit with error */
4181 synprot_error(L_smtp_syntax_error, 501, NULL,
4182 US"Value for RET is invalid");
4187 case ENV_MAIL_OPT_ENVID:
4190 /* Check if the dsn envid has been already set */
4191 if (dsn_envid != NULL)
4193 synprot_error(L_smtp_syntax_error, 501, NULL,
4194 US"ENVID can be specified once only");
4197 dsn_envid = string_copy(value);
4198 DEBUG(D_receive) debug_printf("DSN_ENVID: %s\n", dsn_envid);
4202 /* Handle the AUTH extension. If the value given is not "<>" and either
4203 the ACL says "yes" or there is no ACL but the sending host is
4204 authenticated, we set it up as the authenticated sender. However, if the
4205 authenticator set a condition to be tested, we ignore AUTH on MAIL unless
4206 the condition is met. The value of AUTH is an xtext, which means that +,
4207 = and cntrl chars are coded in hex; however "<>" is unaffected by this
4209 case ENV_MAIL_OPT_AUTH:
4210 if (Ustrcmp(value, "<>") != 0)
4215 if (auth_xtextdecode(value, &authenticated_sender) < 0)
4217 /* Put back terminator overrides for error message */
4220 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4221 US"invalid data for AUTH");
4224 if (acl_smtp_mailauth == NULL)
4226 ignore_msg = US"client not authenticated";
4227 rc = (sender_host_authenticated != NULL)? OK : FAIL;
4231 ignore_msg = US"rejected by ACL";
4232 rc = acl_check(ACL_WHERE_MAILAUTH, NULL, acl_smtp_mailauth,
4233 &user_msg, &log_msg);
4239 if (authenticated_by == NULL ||
4240 authenticated_by->mail_auth_condition == NULL ||
4241 expand_check_condition(authenticated_by->mail_auth_condition,
4242 authenticated_by->name, US"authenticator"))
4243 break; /* Accept the AUTH */
4245 ignore_msg = US"server_mail_auth_condition failed";
4246 if (authenticated_id != NULL)
4247 ignore_msg = string_sprintf("%s: authenticated ID=\"%s\"",
4248 ignore_msg, authenticated_id);
4253 authenticated_sender = NULL;
4254 log_write(0, LOG_MAIN, "ignoring AUTH=%s from %s (%s)",
4255 value, host_and_ident(TRUE), ignore_msg);
4258 /* Should only get DEFER or ERROR here. Put back terminator
4259 overrides for error message */
4264 (void)smtp_handle_acl_fail(ACL_WHERE_MAILAUTH, rc, user_msg,
4271 #ifndef DISABLE_PRDR
4272 case ENV_MAIL_OPT_PRDR:
4274 prdr_requested = TRUE;
4279 case ENV_MAIL_OPT_UTF8:
4280 if (smtputf8_advertised)
4282 DEBUG(D_receive) debug_printf("smtputf8 requested\n");
4283 message_smtputf8 = allow_utf8_domains = TRUE;
4284 received_protocol = string_sprintf("utf8%s", received_protocol);
4288 /* No valid option. Stick back the terminator characters and break
4289 the loop. Do the name-terminator second as extract_option sets
4290 value==name when it found no equal-sign.
4291 An error for a malformed address will occur. */
4292 case ENV_MAIL_OPT_NULL:
4300 /* Break out of for loop if switch() had bad argument or
4301 when start of the email address is reached */
4302 if (arg_error) break;
4305 /* If we have passed the threshold for rate limiting, apply the current
4306 delay, and update it for next time, provided this is a limited host. */
4308 if (smtp_mailcmd_count > smtp_rlm_threshold &&
4309 verify_check_host(&smtp_ratelimit_hosts) == OK)
4311 DEBUG(D_receive) debug_printf("rate limit MAIL: delay %.3g sec\n",
4312 smtp_delay_mail/1000.0);
4313 millisleep((int)smtp_delay_mail);
4314 smtp_delay_mail *= smtp_rlm_factor;
4315 if (smtp_delay_mail > (double)smtp_rlm_limit)
4316 smtp_delay_mail = (double)smtp_rlm_limit;
4319 /* Now extract the address, first applying any SMTP-time rewriting. The
4320 TRUE flag allows "<>" as a sender address. */
4322 raw_sender = rewrite_existflags & rewrite_smtp
4323 ? rewrite_one(smtp_cmd_data, rewrite_smtp, NULL, FALSE, US"",
4324 global_rewrite_rules)
4328 parse_extract_address(raw_sender, &errmess, &start, &end, &sender_domain,
4333 done = synprot_error(L_smtp_syntax_error, 501, smtp_cmd_data, errmess);
4337 sender_address = raw_sender;
4339 /* If there is a configured size limit for mail, check that this message
4340 doesn't exceed it. The check is postponed to this point so that the sender
4343 if (thismessage_size_limit > 0 && message_size > thismessage_size_limit)
4345 smtp_printf("552 Message size exceeds maximum permitted\r\n");
4346 log_write(L_size_reject,
4347 LOG_MAIN|LOG_REJECT, "rejected MAIL FROM:<%s> %s: "
4348 "message too big: size%s=%d max=%d",
4350 host_and_ident(TRUE),
4351 (message_size == INT_MAX)? ">" : "",
4353 thismessage_size_limit);
4354 sender_address = NULL;
4358 /* Check there is enough space on the disk unless configured not to.
4359 When smtp_check_spool_space is set, the check is for thismessage_size_limit
4360 plus the current message - i.e. we accept the message only if it won't
4361 reduce the space below the threshold. Add 5000 to the size to allow for
4362 overheads such as the Received: line and storing of recipients, etc.
4363 By putting the check here, even when SIZE is not given, it allow VRFY
4364 and EXPN etc. to be used when space is short. */
4366 if (!receive_check_fs(
4367 (smtp_check_spool_space && message_size >= 0)?
4368 message_size + 5000 : 0))
4370 smtp_printf("452 Space shortage, please try later\r\n");
4371 sender_address = NULL;
4375 /* If sender_address is unqualified, reject it, unless this is a locally
4376 generated message, or the sending host or net is permitted to send
4377 unqualified addresses - typically local machines behaving as MUAs -
4378 in which case just qualify the address. The flag is set above at the start
4379 of the SMTP connection. */
4381 if (sender_domain == 0 && sender_address[0] != 0)
4383 if (allow_unqualified_sender)
4385 sender_domain = Ustrlen(sender_address) + 1;
4386 sender_address = rewrite_address_qualify(sender_address, FALSE);
4387 DEBUG(D_receive) debug_printf("unqualified address %s accepted\n",
4392 smtp_printf("501 %s: sender address must contain a domain\r\n",
4394 log_write(L_smtp_syntax_error,
4395 LOG_MAIN|LOG_REJECT,
4396 "unqualified sender rejected: <%s> %s%s",
4398 host_and_ident(TRUE),
4400 sender_address = NULL;
4405 /* Apply an ACL check if one is defined, before responding. Afterwards,
4406 when pipelining is not advertised, do another sync check in case the ACL
4407 delayed and the client started sending in the meantime. */
4411 rc = acl_check(ACL_WHERE_MAIL, NULL, acl_smtp_mail, &user_msg, &log_msg);
4412 if (rc == OK && !pipelining_advertised && !check_sync())
4418 if (rc == OK || rc == DISCARD)
4421 smtp_printf("%s%s%s", US"250 OK",
4422 #ifndef DISABLE_PRDR
4423 prdr_requested ? US", PRDR Requested" : US"",
4430 #ifndef DISABLE_PRDR
4432 user_msg = string_sprintf("%s%s", user_msg, US", PRDR Requested");
4434 smtp_user_msg(US"250", user_msg);
4436 smtp_delay_rcpt = smtp_rlr_base;
4437 recipients_discarded = (rc == DISCARD);
4438 was_rej_mail = FALSE;
4442 done = smtp_handle_acl_fail(ACL_WHERE_MAIL, rc, user_msg, log_msg);
4443 sender_address = NULL;
4448 /* The RCPT command requires an address as an operand. There may be any
4449 number of RCPT commands, specifying multiple recipients. We build them all
4450 into a data structure. The start/end values given by parse_extract_address
4451 are not used, as we keep only the extracted address. */
4456 was_rcpt = rcpt_in_progress = TRUE;
4458 /* There must be a sender address; if the sender was rejected and
4459 pipelining was advertised, we assume the client was pipelining, and do not
4460 count this as a protocol error. Reset was_rej_mail so that further RCPTs
4461 get the same treatment. */
4463 if (sender_address == NULL)
4465 if (pipelining_advertised && last_was_rej_mail)
4467 smtp_printf("503 sender not yet given\r\n");
4468 was_rej_mail = TRUE;
4472 done = synprot_error(L_smtp_protocol_error, 503, NULL,
4473 US"sender not yet given");
4474 was_rcpt = FALSE; /* Not a valid RCPT */
4480 /* Check for an operand */
4482 if (smtp_cmd_data[0] == 0)
4484 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4485 US"RCPT must have an address operand");
4490 /* Set the DSN flags orcpt and dsn_flags from the session*/
4496 uschar *name, *value;
4498 if (!extract_option(&name, &value))
4501 if (dsn_advertised && strcmpic(name, US"ORCPT") == 0)
4503 /* Check whether orcpt has been already set */
4506 synprot_error(L_smtp_syntax_error, 501, NULL,
4507 US"ORCPT can be specified once only");
4510 orcpt = string_copy(value);
4511 DEBUG(D_receive) debug_printf("DSN orcpt: %s\n", orcpt);
4514 else if (dsn_advertised && strcmpic(name, US"NOTIFY") == 0)
4516 /* Check if the notify flags have been already set */
4519 synprot_error(L_smtp_syntax_error, 501, NULL,
4520 US"NOTIFY can be specified once only");
4523 if (strcmpic(value, US"NEVER") == 0)
4524 flags |= rf_notify_never;
4531 while (*pp != 0 && *pp != ',') pp++;
4532 if (*pp == ',') *pp++ = 0;
4533 if (strcmpic(p, US"SUCCESS") == 0)
4535 DEBUG(D_receive) debug_printf("DSN: Setting notify success\n");
4536 flags |= rf_notify_success;
4538 else if (strcmpic(p, US"FAILURE") == 0)
4540 DEBUG(D_receive) debug_printf("DSN: Setting notify failure\n");
4541 flags |= rf_notify_failure;
4543 else if (strcmpic(p, US"DELAY") == 0)
4545 DEBUG(D_receive) debug_printf("DSN: Setting notify delay\n");
4546 flags |= rf_notify_delay;
4550 /* Catch any strange values */
4551 synprot_error(L_smtp_syntax_error, 501, NULL,
4552 US"Invalid value for NOTIFY parameter");
4557 DEBUG(D_receive) debug_printf("DSN Flags: %x\n", flags);
4561 /* Unknown option. Stick back the terminator characters and break
4562 the loop. An error for a malformed address will occur. */
4566 DEBUG(D_receive) debug_printf("Invalid RCPT option: %s : %s\n", name, value);
4573 /* Apply SMTP rewriting then extract the working address. Don't allow "<>"
4574 as a recipient address */
4576 recipient = rewrite_existflags & rewrite_smtp
4577 ? rewrite_one(smtp_cmd_data, rewrite_smtp, NULL, FALSE, US"",
4578 global_rewrite_rules)
4581 if (!(recipient = parse_extract_address(recipient, &errmess, &start, &end,
4582 &recipient_domain, FALSE)))
4584 done = synprot_error(L_smtp_syntax_error, 501, smtp_cmd_data, errmess);
4589 /* If the recipient address is unqualified, reject it, unless this is a
4590 locally generated message. However, unqualified addresses are permitted
4591 from a configured list of hosts and nets - typically when behaving as
4592 MUAs rather than MTAs. Sad that SMTP is used for both types of traffic,
4593 really. The flag is set at the start of the SMTP connection.
4595 RFC 1123 talks about supporting "the reserved mailbox postmaster"; I always
4596 assumed this meant "reserved local part", but the revision of RFC 821 and
4597 friends now makes it absolutely clear that it means *mailbox*. Consequently
4598 we must always qualify this address, regardless. */
4600 if (recipient_domain == 0)
4601 if (!(recipient_domain = qualify_recipient(&recipient, smtp_cmd_data,
4608 /* Check maximum allowed */
4610 if (rcpt_count > recipients_max && recipients_max > 0)
4612 if (recipients_max_reject)
4615 smtp_printf("552 too many recipients\r\n");
4617 log_write(0, LOG_MAIN|LOG_REJECT, "too many recipients: message "
4618 "rejected: sender=<%s> %s", sender_address, host_and_ident(TRUE));
4623 smtp_printf("452 too many recipients\r\n");
4625 log_write(0, LOG_MAIN|LOG_REJECT, "too many recipients: excess "
4626 "temporarily rejected: sender=<%s> %s", sender_address,
4627 host_and_ident(TRUE));
4634 /* If we have passed the threshold for rate limiting, apply the current
4635 delay, and update it for next time, provided this is a limited host. */
4637 if (rcpt_count > smtp_rlr_threshold &&
4638 verify_check_host(&smtp_ratelimit_hosts) == OK)
4640 DEBUG(D_receive) debug_printf("rate limit RCPT: delay %.3g sec\n",
4641 smtp_delay_rcpt/1000.0);
4642 millisleep((int)smtp_delay_rcpt);
4643 smtp_delay_rcpt *= smtp_rlr_factor;
4644 if (smtp_delay_rcpt > (double)smtp_rlr_limit)
4645 smtp_delay_rcpt = (double)smtp_rlr_limit;
4648 /* If the MAIL ACL discarded all the recipients, we bypass ACL checking
4649 for them. Otherwise, check the access control list for this recipient. As
4650 there may be a delay in this, re-check for a synchronization error
4651 afterwards, unless pipelining was advertised. */
4653 if (recipients_discarded)
4656 if ( (rc = acl_check(ACL_WHERE_RCPT, recipient, acl_smtp_rcpt, &user_msg,
4658 && !pipelining_advertised && !check_sync())
4661 /* The ACL was happy */
4666 smtp_user_msg(US"250", user_msg);
4668 smtp_printf("250 Accepted\r\n");
4669 receive_add_recipient(recipient, -1);
4671 /* Set the dsn flags in the recipients_list */
4672 recipients_list[recipients_count-1].orcpt = orcpt;
4673 recipients_list[recipients_count-1].dsn_flags = flags;
4675 DEBUG(D_receive) debug_printf("DSN: orcpt: %s flags: %d\n",
4676 recipients_list[recipients_count-1].orcpt,
4677 recipients_list[recipients_count-1].dsn_flags);
4680 /* The recipient was discarded */
4682 else if (rc == DISCARD)
4685 smtp_user_msg(US"250", user_msg);
4687 smtp_printf("250 Accepted\r\n");
4690 log_write(0, LOG_MAIN|LOG_REJECT, "%s F=<%s> RCPT %s: "
4691 "discarded by %s ACL%s%s", host_and_ident(TRUE),
4692 sender_address_unrewritten? sender_address_unrewritten : sender_address,
4693 smtp_cmd_argument, recipients_discarded? "MAIL" : "RCPT",
4694 log_msg ? US": " : US"", log_msg ? log_msg : US"");
4697 /* Either the ACL failed the address, or it was deferred. */
4701 if (rc == FAIL) rcpt_fail_count++; else rcpt_defer_count++;
4702 done = smtp_handle_acl_fail(ACL_WHERE_RCPT, rc, user_msg, log_msg);
4707 /* The DATA command is legal only if it follows successful MAIL FROM
4708 and RCPT TO commands. However, if pipelining is advertised, a bad DATA is
4709 not counted as a protocol error if it follows RCPT (which must have been
4710 rejected if there are no recipients.) This function is complete when a
4711 valid DATA command is encountered.
4713 Note concerning the code used: RFC 2821 says this:
4715 - If there was no MAIL, or no RCPT, command, or all such commands
4716 were rejected, the server MAY return a "command out of sequence"
4717 (503) or "no valid recipients" (554) reply in response to the
4720 The example in the pipelining RFC 2920 uses 554, but I use 503 here
4721 because it is the same whether pipelining is in use or not.
4723 If all the RCPT commands that precede DATA provoked the same error message
4724 (often indicating some kind of system error), it is helpful to include it
4725 with the DATA rejection (an idea suggested by Tony Finch). */
4732 if (chunking_state != CHUNKING_OFFERED)
4734 done = synprot_error(L_smtp_protocol_error, 503, NULL,
4735 US"BDAT command used when CHUNKING not advertised");
4739 /* grab size, endmarker */
4741 if (sscanf(CS smtp_cmd_data, "%u %n", &chunking_datasize, &n) < 1)
4743 done = synprot_error(L_smtp_protocol_error, 501, NULL,
4744 US"missing size for BDAT command");
4747 chunking_state = strcmpic(smtp_cmd_data+n, US"LAST") == 0
4748 ? CHUNKING_LAST : CHUNKING_ACTIVE;
4749 chunking_data_left = chunking_datasize;
4751 lwr_receive_getc = receive_getc;
4752 lwr_receive_ungetc = receive_ungetc;
4753 receive_getc = bdat_getc;
4754 receive_ungetc = bdat_ungetc;
4757 debug_printf("chunking state %d\n", (int)chunking_state);
4764 DATA_BDAT: /* Common code for DATA and BDAT */
4765 if (!discarded && recipients_count <= 0)
4767 if (rcpt_smtp_response_same && rcpt_smtp_response != NULL)
4769 uschar *code = US"503";
4770 int len = Ustrlen(rcpt_smtp_response);
4771 smtp_respond(code, 3, FALSE, US"All RCPT commands were rejected with "
4773 /* Responses from smtp_printf() will have \r\n on the end */
4774 if (len > 2 && rcpt_smtp_response[len-2] == '\r')
4775 rcpt_smtp_response[len-2] = 0;
4776 smtp_respond(code, 3, FALSE, rcpt_smtp_response);
4778 if (pipelining_advertised && last_was_rcpt)
4779 smtp_printf("503 Valid RCPT command must precede %s\r\n",
4780 smtp_names[smtp_connection_had[smtp_ch_index-1]]);
4782 done = synprot_error(L_smtp_protocol_error, 503, NULL,
4783 smtp_connection_had[smtp_ch_index-1] == SCH_DATA
4784 ? US"valid RCPT command must precede DATA"
4785 : US"valid RCPT command must precede BDAT");
4787 if (chunking_state > CHUNKING_OFFERED)
4792 if (toomany && recipients_max_reject)
4794 sender_address = NULL; /* This will allow a new MAIL without RSET */
4795 sender_address_unrewritten = NULL;
4796 smtp_printf("554 Too many recipients\r\n");
4800 if (chunking_state > CHUNKING_OFFERED)
4801 rc = OK; /* No predata ACL or go-ahead output for BDAT */
4804 /* If there is an ACL, re-check the synchronization afterwards, since the
4805 ACL may have delayed. To handle cutthrough delivery enforce a dummy call
4806 to get the DATA command sent. */
4808 if (acl_smtp_predata == NULL && cutthrough.fd < 0)
4812 uschar * acl = acl_smtp_predata ? acl_smtp_predata : US"accept";
4813 enable_dollar_recipients = TRUE;
4814 rc = acl_check(ACL_WHERE_PREDATA, NULL, acl, &user_msg,
4816 enable_dollar_recipients = FALSE;
4817 if (rc == OK && !check_sync())
4821 { /* Either the ACL failed the address, or it was deferred. */
4822 done = smtp_handle_acl_fail(ACL_WHERE_PREDATA, rc, user_msg, log_msg);
4828 smtp_user_msg(US"354", user_msg);
4831 "354 Enter message, ending with \".\" on a line by itself\r\n");
4835 if (smtp_in) /* all ACKs needed to ramp window up for bulk data */
4836 (void) setsockopt(fileno(smtp_in), IPPROTO_TCP, TCP_QUICKACK,
4837 US &on, sizeof(on));
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 */