Update eximstats to watch out for senders sending 'HELO [IpAddr]'
[exim.git] / src / src / smtp_in.c
CommitLineData
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1/*************************************************
2* Exim - an Internet mail transport agent *
3*************************************************/
4
c4ceed07 5/* Copyright (c) University of Cambridge 1995 - 2012 */
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6/* See the file NOTICE for conditions of use and distribution. */
7
8/* Functions for handling an incoming SMTP call. */
9
10
11#include "exim.h"
12
13
14/* Initialize for TCP wrappers if so configured. It appears that the macro
15HAVE_IPV6 is used in some versions of the tcpd.h header, so we unset it before
16including that header, and restore its value afterwards. */
17
18#ifdef USE_TCP_WRAPPERS
19
20 #if HAVE_IPV6
21 #define EXIM_HAVE_IPV6
22 #endif
23 #undef HAVE_IPV6
24 #include <tcpd.h>
25 #undef HAVE_IPV6
26 #ifdef EXIM_HAVE_IPV6
27 #define HAVE_IPV6 TRUE
28 #endif
29
30int allow_severity = LOG_INFO;
31int deny_severity = LOG_NOTICE;
5dc43717 32uschar *tcp_wrappers_name;
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33#endif
34
35
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36/* Size of buffer for reading SMTP commands. We used to use 512, as defined
37by RFC 821. However, RFC 1869 specifies that this must be increased for SMTP
38commands that accept arguments, and this in particular applies to AUTH, where
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39the data can be quite long. More recently this value was 2048 in Exim;
40however, RFC 4954 (circa 2007) recommends 12288 bytes to handle AUTH. Clients
41such as Thunderbird will send an AUTH with an initial-response for GSSAPI.
42The maximum size of a Kerberos ticket under Windows 2003 is 12000 bytes, and
43we need room to handle large base64-encoded AUTHs for GSSAPI.
44*/
45
46#define smtp_cmd_buffer_size 16384
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47
48/* Size of buffer for reading SMTP incoming packets */
49
50#define in_buffer_size 8192
51
52/* Structure for SMTP command list */
53
54typedef struct {
1ba28e2b 55 const char *name;
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56 int len;
57 short int cmd;
58 short int has_arg;
59 short int is_mail_cmd;
60} smtp_cmd_list;
61
62/* Codes for identifying commands. We order them so that those that come first
63are those for which synchronization is always required. Checking this can help
64block some spam. */
65
66enum {
67 /* These commands are required to be synchronized, i.e. to be the last in a
68 block of commands when pipelining. */
69
70 HELO_CMD, EHLO_CMD, DATA_CMD, /* These are listed in the pipelining */
71 VRFY_CMD, EXPN_CMD, NOOP_CMD, /* RFC as requiring synchronization */
72 ETRN_CMD, /* This by analogy with TURN from the RFC */
73 STARTTLS_CMD, /* Required by the STARTTLS RFC */
74
75 /* This is a dummy to identify the non-sync commands when pipelining */
76
77 NON_SYNC_CMD_PIPELINING,
78
79 /* These commands need not be synchronized when pipelining */
80
81 MAIL_CMD, RCPT_CMD, RSET_CMD,
82
83 /* This is a dummy to identify the non-sync commands when not pipelining */
84
85 NON_SYNC_CMD_NON_PIPELINING,
86
87 /* I have been unable to find a statement about the use of pipelining
88 with AUTH, so to be on the safe side it is here, though I kind of feel
89 it should be up there with the synchronized commands. */
90
91 AUTH_CMD,
92
93 /* I'm not sure about these, but I don't think they matter. */
94
95 QUIT_CMD, HELP_CMD,
96
97 /* These are specials that don't correspond to actual commands */
98
99 EOF_CMD, OTHER_CMD, BADARG_CMD, BADCHAR_CMD, BADSYN_CMD,
100 TOO_MANY_NONMAIL_CMD };
101
102
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103/* This is a convenience macro for adding the identity of an SMTP command
104to the circular buffer that holds a list of the last n received. */
105
106#define HAD(n) \
107 smtp_connection_had[smtp_ch_index++] = n; \
108 if (smtp_ch_index >= SMTP_HBUFF_SIZE) smtp_ch_index = 0
109
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110
111/*************************************************
112* Local static variables *
113*************************************************/
114
115static auth_instance *authenticated_by;
116static BOOL auth_advertised;
117#ifdef SUPPORT_TLS
118static BOOL tls_advertised;
119#endif
120static BOOL esmtp;
121static BOOL helo_required = FALSE;
122static BOOL helo_verify = FALSE;
123static BOOL helo_seen;
124static BOOL helo_accept_junk;
125static BOOL count_nonmail;
126static BOOL pipelining_advertised;
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127static BOOL rcpt_smtp_response_same;
128static BOOL rcpt_in_progress;
059ec3d9 129static int nonmail_command_count;
8f128379 130static BOOL smtp_exit_function_called = 0;
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131static int synprot_error_count;
132static int unknown_command_count;
133static int sync_cmd_limit;
134static int smtp_write_error = 0;
135
2679d413 136static uschar *rcpt_smtp_response;
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137static uschar *smtp_data_buffer;
138static uschar *smtp_cmd_data;
139
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140/* We need to know the position of RSET, HELO, EHLO, AUTH, and STARTTLS. Their
141final fields of all except AUTH are forced TRUE at the start of a new message
142setup, to allow one of each between messages that is not counted as a nonmail
143command. (In fact, only one of HELO/EHLO is not counted.) Also, we have to
144allow a new EHLO after starting up TLS.
145
146AUTH is "falsely" labelled as a mail command initially, so that it doesn't get
147counted. However, the flag is changed when AUTH is received, so that multiple
148failing AUTHs will eventually hit the limit. After a successful AUTH, another
149AUTH is already forbidden. After a TLS session is started, AUTH's flag is again
150forced TRUE, to allow for the re-authentication that can happen at that point.
151
152QUIT is also "falsely" labelled as a mail command so that it doesn't up the
153count of non-mail commands and possibly provoke an error. */
154
155static smtp_cmd_list cmd_list[] = {
156 { "rset", sizeof("rset")-1, RSET_CMD, FALSE, FALSE }, /* First */
157 { "helo", sizeof("helo")-1, HELO_CMD, TRUE, FALSE },
158 { "ehlo", sizeof("ehlo")-1, EHLO_CMD, TRUE, FALSE },
159 { "auth", sizeof("auth")-1, AUTH_CMD, TRUE, TRUE },
160 #ifdef SUPPORT_TLS
161 { "starttls", sizeof("starttls")-1, STARTTLS_CMD, FALSE, FALSE },
162 #endif
163
164/* If you change anything above here, also fix the definitions below. */
165
166 { "mail from:", sizeof("mail from:")-1, MAIL_CMD, TRUE, TRUE },
167 { "rcpt to:", sizeof("rcpt to:")-1, RCPT_CMD, TRUE, TRUE },
168 { "data", sizeof("data")-1, DATA_CMD, FALSE, TRUE },
169 { "quit", sizeof("quit")-1, QUIT_CMD, FALSE, TRUE },
170 { "noop", sizeof("noop")-1, NOOP_CMD, TRUE, FALSE },
171 { "etrn", sizeof("etrn")-1, ETRN_CMD, TRUE, FALSE },
172 { "vrfy", sizeof("vrfy")-1, VRFY_CMD, TRUE, FALSE },
173 { "expn", sizeof("expn")-1, EXPN_CMD, TRUE, FALSE },
174 { "help", sizeof("help")-1, HELP_CMD, TRUE, FALSE }
175};
176
177static smtp_cmd_list *cmd_list_end =
178 cmd_list + sizeof(cmd_list)/sizeof(smtp_cmd_list);
179
180#define CMD_LIST_RSET 0
181#define CMD_LIST_HELO 1
182#define CMD_LIST_EHLO 2
183#define CMD_LIST_AUTH 3
184#define CMD_LIST_STARTTLS 4
185
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186/* This list of names is used for performing the smtp_no_mail logging action.
187It must be kept in step with the SCH_xxx enumerations. */
188
189static uschar *smtp_names[] =
190 {
191 US"NONE", US"AUTH", US"DATA", US"EHLO", US"ETRN", US"EXPN", US"HELO",
192 US"HELP", US"MAIL", US"NOOP", US"QUIT", US"RCPT", US"RSET", US"STARTTLS",
193 US"VRFY" };
194
059ec3d9 195static uschar *protocols[] = {
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196 US"local-smtp", /* HELO */
197 US"local-smtps", /* The rare case EHLO->STARTTLS->HELO */
198 US"local-esmtp", /* EHLO */
199 US"local-esmtps", /* EHLO->STARTTLS->EHLO */
200 US"local-esmtpa", /* EHLO->AUTH */
201 US"local-esmtpsa" /* EHLO->STARTTLS->EHLO->AUTH */
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202 };
203
204#define pnormal 0
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205#define pextend 2
206#define pcrpted 1 /* added to pextend or pnormal */
207#define pauthed 2 /* added to pextend */
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208#define pnlocal 6 /* offset to remove "local" */
209
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210/* Sanity check and validate optional args to MAIL FROM: envelope */
211enum {
212 ENV_MAIL_OPT_SIZE, ENV_MAIL_OPT_BODY, ENV_MAIL_OPT_AUTH,
213 ENV_MAIL_OPT_PRDR, ENV_MAIL_OPT_NULL
214 };
215typedef struct {
216 uschar * name; /* option requested during MAIL cmd */
217 int value; /* enum type */
218 BOOL need_value; /* TRUE requires value (name=value pair format)
219 FALSE is a singleton */
220 } env_mail_type_t;
221static env_mail_type_t env_mail_type_list[] = {
222 { US"SIZE", ENV_MAIL_OPT_SIZE, TRUE },
223 { US"BODY", ENV_MAIL_OPT_BODY, TRUE },
224 { US"AUTH", ENV_MAIL_OPT_AUTH, TRUE },
225 { US"NULL", ENV_MAIL_OPT_NULL, FALSE } /* Placeholder for ending */
226 };
227
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228/* When reading SMTP from a remote host, we have to use our own versions of the
229C input-reading functions, in order to be able to flush the SMTP output only
230when about to read more data from the socket. This is the only way to get
231optimal performance when the client is using pipelining. Flushing for every
232command causes a separate packet and reply packet each time; saving all the
233responses up (when pipelining) combines them into one packet and one response.
234
235For simplicity, these functions are used for *all* SMTP input, not only when
236receiving over a socket. However, after setting up a secure socket (SSL), input
237is read via the OpenSSL library, and another set of functions is used instead
238(see tls.c).
239
240These functions are set in the receive_getc etc. variables and called with the
241same interface as the C functions. However, since there can only ever be
242one incoming SMTP call, we just use a single buffer and flags. There is no need
243to implement a complicated private FILE-like structure.*/
244
245static uschar *smtp_inbuffer;
246static uschar *smtp_inptr;
247static uschar *smtp_inend;
248static int smtp_had_eof;
249static int smtp_had_error;
250
251
252/*************************************************
253* SMTP version of getc() *
254*************************************************/
255
256/* This gets the next byte from the SMTP input buffer. If the buffer is empty,
257it flushes the output, and refills the buffer, with a timeout. The signal
258handler is set appropriately by the calling function. This function is not used
259after a connection has negotated itself into an TLS/SSL state.
260
261Arguments: none
262Returns: the next character or EOF
263*/
264
265int
266smtp_getc(void)
267{
268if (smtp_inptr >= smtp_inend)
269 {
270 int rc, save_errno;
271 fflush(smtp_out);
272 if (smtp_receive_timeout > 0) alarm(smtp_receive_timeout);
273 rc = read(fileno(smtp_in), smtp_inbuffer, in_buffer_size);
274 save_errno = errno;
275 alarm(0);
276 if (rc <= 0)
277 {
278 /* Must put the error text in fixed store, because this might be during
279 header reading, where it releases unused store above the header. */
280 if (rc < 0)
281 {
282 smtp_had_error = save_errno;
283 smtp_read_error = string_copy_malloc(
284 string_sprintf(" (error: %s)", strerror(save_errno)));
285 }
286 else smtp_had_eof = 1;
287 return EOF;
288 }
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289#ifndef DISABLE_DKIM
290 dkim_exim_verify_feed(smtp_inbuffer, rc);
291#endif
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292 smtp_inend = smtp_inbuffer + rc;
293 smtp_inptr = smtp_inbuffer;
294 }
295return *smtp_inptr++;
296}
297
298
299
300/*************************************************
301* SMTP version of ungetc() *
302*************************************************/
303
304/* Puts a character back in the input buffer. Only ever
305called once.
306
307Arguments:
308 ch the character
309
310Returns: the character
311*/
312
313int
314smtp_ungetc(int ch)
315{
316*(--smtp_inptr) = ch;
317return ch;
318}
319
320
321
322
323/*************************************************
324* SMTP version of feof() *
325*************************************************/
326
327/* Tests for a previous EOF
328
329Arguments: none
330Returns: non-zero if the eof flag is set
331*/
332
333int
334smtp_feof(void)
335{
336return smtp_had_eof;
337}
338
339
340
341
342/*************************************************
343* SMTP version of ferror() *
344*************************************************/
345
346/* Tests for a previous read error, and returns with errno
347restored to what it was when the error was detected.
348
349Arguments: none
350Returns: non-zero if the error flag is set
351*/
352
353int
354smtp_ferror(void)
355{
356errno = smtp_had_error;
357return smtp_had_error;
358}
359
360
361
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362/*************************************************
363* Test for characters in the SMTP buffer *
364*************************************************/
365
366/* Used at the end of a message
367
368Arguments: none
369Returns: TRUE/FALSE
370*/
371
372BOOL
373smtp_buffered(void)
374{
375return smtp_inptr < smtp_inend;
376}
377
378
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379
380/*************************************************
381* Write formatted string to SMTP channel *
382*************************************************/
383
384/* This is a separate function so that we don't have to repeat everything for
385TLS support or debugging. It is global so that the daemon and the
386authentication functions can use it. It does not return any error indication,
387because major problems such as dropped connections won't show up till an output
388flush for non-TLS connections. The smtp_fflush() function is available for
389checking that: for convenience, TLS output errors are remembered here so that
390they are also picked up later by smtp_fflush().
391
392Arguments:
393 format format string
394 ... optional arguments
395
396Returns: nothing
397*/
398
399void
1ba28e2b 400smtp_printf(const char *format, ...)
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401{
402va_list ap;
403
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404va_start(ap, format);
405smtp_vprintf(format, ap);
406va_end(ap);
407}
408
409/* This is split off so that verify.c:respond_printf() can, in effect, call
410smtp_printf(), bearing in mind that in C a vararg function can't directly
fb08281f 411call another vararg function, only a function which accepts a va_list. */
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412
413void
1ba28e2b 414smtp_vprintf(const char *format, va_list ap)
ce552449 415{
fb08281f
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416BOOL yield;
417
418yield = string_vformat(big_buffer, big_buffer_size, format, ap);
ce552449 419
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420DEBUG(D_receive)
421 {
fb08281f
DW
422 void *reset_point = store_get(0);
423 uschar *msg_copy, *cr, *end;
424 msg_copy = string_copy(big_buffer);
425 end = msg_copy + Ustrlen(msg_copy);
426 while ((cr = Ustrchr(msg_copy, '\r')) != NULL) /* lose CRs */
427 memmove(cr, cr + 1, (end--) - cr);
428 debug_printf("SMTP>> %s", msg_copy);
429 store_reset(reset_point);
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430 }
431
fb08281f 432if (!yield)
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433 {
434 log_write(0, LOG_MAIN|LOG_PANIC, "string too large in smtp_printf()");
435 smtp_closedown(US"Unexpected error");
436 exim_exit(EXIT_FAILURE);
437 }
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438
439/* If this is the first output for a (non-batch) RCPT command, see if all RCPTs
440have had the same. Note: this code is also present in smtp_respond(). It would
441be tidier to have it only in one place, but when it was added, it was easier to
442do it that way, so as not to have to mess with the code for the RCPT command,
443which sometimes uses smtp_printf() and sometimes smtp_respond(). */
444
445if (rcpt_in_progress)
446 {
447 if (rcpt_smtp_response == NULL)
448 rcpt_smtp_response = string_copy(big_buffer);
449 else if (rcpt_smtp_response_same &&
450 Ustrcmp(rcpt_smtp_response, big_buffer) != 0)
451 rcpt_smtp_response_same = FALSE;
452 rcpt_in_progress = FALSE;
453 }
059ec3d9 454
2679d413 455/* Now write the string */
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456
457#ifdef SUPPORT_TLS
817d9f57 458if (tls_in.active >= 0)
059ec3d9 459 {
817d9f57
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460 if (tls_write(TRUE, big_buffer, Ustrlen(big_buffer)) < 0)
461 smtp_write_error = -1;
059ec3d9
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462 }
463else
464#endif
465
2679d413 466if (fprintf(smtp_out, "%s", big_buffer) < 0) smtp_write_error = -1;
059ec3d9
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467}
468
469
470
471/*************************************************
472* Flush SMTP out and check for error *
473*************************************************/
474
475/* This function isn't currently used within Exim (it detects errors when it
476tries to read the next SMTP input), but is available for use in local_scan().
477For non-TLS connections, it flushes the output and checks for errors. For
478TLS-connections, it checks for a previously-detected TLS write error.
479
480Arguments: none
481Returns: 0 for no error; -1 after an error
482*/
483
484int
485smtp_fflush(void)
486{
817d9f57 487if (tls_in.active < 0 && fflush(smtp_out) != 0) smtp_write_error = -1;
059ec3d9
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488return smtp_write_error;
489}
490
491
492
493/*************************************************
494* SMTP command read timeout *
495*************************************************/
496
497/* Signal handler for timing out incoming SMTP commands. This attempts to
498finish off tidily.
499
500Argument: signal number (SIGALRM)
501Returns: nothing
502*/
503
504static void
505command_timeout_handler(int sig)
506{
507sig = sig; /* Keep picky compilers happy */
508log_write(L_lost_incoming_connection,
509 LOG_MAIN, "SMTP command timeout on%s connection from %s",
817d9f57 510 (tls_in.active >= 0)? " TLS" : "",
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511 host_and_ident(FALSE));
512if (smtp_batched_input)
513 moan_smtp_batch(NULL, "421 SMTP command timeout"); /* Does not return */
8f128379
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514smtp_notquit_exit(US"command-timeout", US"421",
515 US"%s: SMTP command timeout - closing connection", smtp_active_hostname);
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516exim_exit(EXIT_FAILURE);
517}
518
519
520
521/*************************************************
522* SIGTERM received *
523*************************************************/
524
525/* Signal handler for handling SIGTERM. Again, try to finish tidily.
526
527Argument: signal number (SIGTERM)
528Returns: nothing
529*/
530
531static void
532command_sigterm_handler(int sig)
533{
534sig = sig; /* Keep picky compilers happy */
535log_write(0, LOG_MAIN, "%s closed after SIGTERM", smtp_get_connection_info());
536if (smtp_batched_input)
537 moan_smtp_batch(NULL, "421 SIGTERM received"); /* Does not return */
8f128379
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538smtp_notquit_exit(US"signal-exit", US"421",
539 US"%s: Service not available - closing connection", smtp_active_hostname);
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540exim_exit(EXIT_FAILURE);
541}
542
543
544
a14e5636 545
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546/*************************************************
547* Read one command line *
548*************************************************/
549
550/* Strictly, SMTP commands coming over the net are supposed to end with CRLF.
551There are sites that don't do this, and in any case internal SMTP probably
552should check only for LF. Consequently, we check here for LF only. The line
553ends up with [CR]LF removed from its end. If we get an overlong line, treat as
3ee512ff
PH
554an unknown command. The command is read into the global smtp_cmd_buffer so that
555it is available via $smtp_command.
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556
557The character reading routine sets up a timeout for each block actually read
558from the input (which may contain more than one command). We set up a special
559signal handler that closes down the session on a timeout. Control does not
560return when it runs.
561
562Arguments:
563 check_sync if TRUE, check synchronization rules if global option is TRUE
564
565Returns: a code identifying the command (enumerated above)
566*/
567
568static int
569smtp_read_command(BOOL check_sync)
570{
571int c;
572int ptr = 0;
573smtp_cmd_list *p;
574BOOL hadnull = FALSE;
575
576os_non_restarting_signal(SIGALRM, command_timeout_handler);
577
578while ((c = (receive_getc)()) != '\n' && c != EOF)
579 {
3ee512ff 580 if (ptr >= smtp_cmd_buffer_size)
059ec3d9
PH
581 {
582 os_non_restarting_signal(SIGALRM, sigalrm_handler);
583 return OTHER_CMD;
584 }
585 if (c == 0)
586 {
587 hadnull = TRUE;
588 c = '?';
589 }
3ee512ff 590 smtp_cmd_buffer[ptr++] = c;
059ec3d9
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591 }
592
593receive_linecount++; /* For BSMTP errors */
594os_non_restarting_signal(SIGALRM, sigalrm_handler);
595
596/* If hit end of file, return pseudo EOF command. Whether we have a
597part-line already read doesn't matter, since this is an error state. */
598
599if (c == EOF) return EOF_CMD;
600
601/* Remove any CR and white space at the end of the line, and terminate the
602string. */
603
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604while (ptr > 0 && isspace(smtp_cmd_buffer[ptr-1])) ptr--;
605smtp_cmd_buffer[ptr] = 0;
059ec3d9 606
3ee512ff 607DEBUG(D_receive) debug_printf("SMTP<< %s\n", smtp_cmd_buffer);
059ec3d9
PH
608
609/* NULLs are not allowed in SMTP commands */
610
611if (hadnull) return BADCHAR_CMD;
612
613/* Scan command list and return identity, having set the data pointer
614to the start of the actual data characters. Check for SMTP synchronization
615if required. */
616
617for (p = cmd_list; p < cmd_list_end; p++)
618 {
084efe8d
PH
619 if (strncmpic(smtp_cmd_buffer, US p->name, p->len) == 0 &&
620 (smtp_cmd_buffer[p->len-1] == ':' || /* "mail from:" or "rcpt to:" */
621 smtp_cmd_buffer[p->len] == 0 ||
622 smtp_cmd_buffer[p->len] == ' '))
059ec3d9
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623 {
624 if (smtp_inptr < smtp_inend && /* Outstanding input */
625 p->cmd < sync_cmd_limit && /* Command should sync */
626 check_sync && /* Local flag set */
627 smtp_enforce_sync && /* Global flag set */
628 sender_host_address != NULL && /* Not local input */
629 !sender_host_notsocket) /* Really is a socket */
630 return BADSYN_CMD;
631
ca86f471
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632 /* The variables $smtp_command and $smtp_command_argument point into the
633 unmodified input buffer. A copy of the latter is taken for actual
634 processing, so that it can be chopped up into separate parts if necessary,
635 for example, when processing a MAIL command options such as SIZE that can
636 follow the sender address. */
059ec3d9 637
3ee512ff 638 smtp_cmd_argument = smtp_cmd_buffer + p->len;
ca86f471
PH
639 while (isspace(*smtp_cmd_argument)) smtp_cmd_argument++;
640 Ustrcpy(smtp_data_buffer, smtp_cmd_argument);
641 smtp_cmd_data = smtp_data_buffer;
059ec3d9
PH
642
643 /* Count non-mail commands from those hosts that are controlled in this
644 way. The default is all hosts. We don't waste effort checking the list
645 until we get a non-mail command, but then cache the result to save checking
646 again. If there's a DEFER while checking the host, assume it's in the list.
647
648 Note that one instance of RSET, EHLO/HELO, and STARTTLS is allowed at the
649 start of each incoming message by fiddling with the value in the table. */
650
651 if (!p->is_mail_cmd)
652 {
653 if (count_nonmail == TRUE_UNSET) count_nonmail =
654 verify_check_host(&smtp_accept_max_nonmail_hosts) != FAIL;
655 if (count_nonmail && ++nonmail_command_count > smtp_accept_max_nonmail)
656 return TOO_MANY_NONMAIL_CMD;
657 }
658
ca86f471
PH
659 /* If there is data for a command that does not expect it, generate the
660 error here. */
059ec3d9 661
ca86f471 662 return (p->has_arg || *smtp_cmd_data == 0)? p->cmd : BADARG_CMD;
059ec3d9
PH
663 }
664 }
665
666/* Enforce synchronization for unknown commands */
667
668if (smtp_inptr < smtp_inend && /* Outstanding input */
669 check_sync && /* Local flag set */
670 smtp_enforce_sync && /* Global flag set */
671 sender_host_address != NULL && /* Not local input */
672 !sender_host_notsocket) /* Really is a socket */
673 return BADSYN_CMD;
674
675return OTHER_CMD;
676}
677
678
679
680/*************************************************
a14e5636
PH
681* Recheck synchronization *
682*************************************************/
683
684/* Synchronization checks can never be perfect because a packet may be on its
685way but not arrived when the check is done. Such checks can in any case only be
686done when TLS is not in use. Normally, the checks happen when commands are
687read: Exim ensures that there is no more input in the input buffer. In normal
688cases, the response to the command will be fast, and there is no further check.
689
690However, for some commands an ACL is run, and that can include delays. In those
691cases, it is useful to do another check on the input just before sending the
692response. This also applies at the start of a connection. This function does
693that check by means of the select() function, as long as the facility is not
694disabled or inappropriate. A failure of select() is ignored.
695
696When there is unwanted input, we read it so that it appears in the log of the
697error.
698
699Arguments: none
700Returns: TRUE if all is well; FALSE if there is input pending
701*/
702
703static BOOL
704check_sync(void)
705{
706int fd, rc;
707fd_set fds;
708struct timeval tzero;
709
710if (!smtp_enforce_sync || sender_host_address == NULL ||
817d9f57 711 sender_host_notsocket || tls_in.active >= 0)
a14e5636
PH
712 return TRUE;
713
714fd = fileno(smtp_in);
715FD_ZERO(&fds);
716FD_SET(fd, &fds);
717tzero.tv_sec = 0;
718tzero.tv_usec = 0;
719rc = select(fd + 1, (SELECT_ARG2_TYPE *)&fds, NULL, NULL, &tzero);
720
721if (rc <= 0) return TRUE; /* Not ready to read */
722rc = smtp_getc();
723if (rc < 0) return TRUE; /* End of file or error */
724
725smtp_ungetc(rc);
726rc = smtp_inend - smtp_inptr;
727if (rc > 150) rc = 150;
728smtp_inptr[rc] = 0;
729return FALSE;
730}
731
732
733
734/*************************************************
059ec3d9
PH
735* Forced closedown of call *
736*************************************************/
737
738/* This function is called from log.c when Exim is dying because of a serious
739disaster, and also from some other places. If an incoming non-batched SMTP
740channel is open, it swallows the rest of the incoming message if in the DATA
741phase, sends the reply string, and gives an error to all subsequent commands
742except QUIT. The existence of an SMTP call is detected by the non-NULLness of
743smtp_in.
744
8f128379
PH
745Arguments:
746 message SMTP reply string to send, excluding the code
747
059ec3d9
PH
748Returns: nothing
749*/
750
751void
752smtp_closedown(uschar *message)
753{
754if (smtp_in == NULL || smtp_batched_input) return;
755receive_swallow_smtp();
756smtp_printf("421 %s\r\n", message);
757
758for (;;)
759 {
760 switch(smtp_read_command(FALSE))
761 {
762 case EOF_CMD:
763 return;
764
765 case QUIT_CMD:
766 smtp_printf("221 %s closing connection\r\n", smtp_active_hostname);
767 mac_smtp_fflush();
768 return;
769
770 case RSET_CMD:
771 smtp_printf("250 Reset OK\r\n");
772 break;
773
774 default:
775 smtp_printf("421 %s\r\n", message);
776 break;
777 }
778 }
779}
780
781
782
783
784/*************************************************
785* Set up connection info for logging *
786*************************************************/
787
788/* This function is called when logging information about an SMTP connection.
789It sets up appropriate source information, depending on the type of connection.
dac79d3e
PH
790If sender_fullhost is NULL, we are at a very early stage of the connection;
791just use the IP address.
059ec3d9
PH
792
793Argument: none
794Returns: a string describing the connection
795*/
796
797uschar *
798smtp_get_connection_info(void)
799{
dac79d3e
PH
800uschar *hostname = (sender_fullhost == NULL)?
801 sender_host_address : sender_fullhost;
802
059ec3d9 803if (host_checking)
dac79d3e 804 return string_sprintf("SMTP connection from %s", hostname);
059ec3d9
PH
805
806if (sender_host_unknown || sender_host_notsocket)
807 return string_sprintf("SMTP connection from %s", sender_ident);
808
809if (is_inetd)
dac79d3e 810 return string_sprintf("SMTP connection from %s (via inetd)", hostname);
059ec3d9
PH
811
812if ((log_extra_selector & LX_incoming_interface) != 0 &&
813 interface_address != NULL)
dac79d3e 814 return string_sprintf("SMTP connection from %s I=[%s]:%d", hostname,
059ec3d9
PH
815 interface_address, interface_port);
816
dac79d3e 817return string_sprintf("SMTP connection from %s", hostname);
059ec3d9
PH
818}
819
820
821
822/*************************************************
b4ed4da0
PH
823* Log lack of MAIL if so configured *
824*************************************************/
825
826/* This function is called when an SMTP session ends. If the log selector
827smtp_no_mail is set, write a log line giving some details of what has happened
828in the SMTP session.
829
830Arguments: none
831Returns: nothing
832*/
833
834void
835smtp_log_no_mail(void)
836{
837int size, ptr, i;
838uschar *s, *sep;
839
840if (smtp_mailcmd_count > 0 || (log_extra_selector & LX_smtp_no_mail) == 0)
841 return;
842
843s = NULL;
844size = ptr = 0;
845
846if (sender_host_authenticated != NULL)
847 {
848 s = string_append(s, &size, &ptr, 2, US" A=", sender_host_authenticated);
849 if (authenticated_id != NULL)
850 s = string_append(s, &size, &ptr, 2, US":", authenticated_id);
851 }
852
853#ifdef SUPPORT_TLS
817d9f57
JH
854if ((log_extra_selector & LX_tls_cipher) != 0 && tls_in.cipher != NULL)
855 s = string_append(s, &size, &ptr, 2, US" X=", tls_in.cipher);
b4ed4da0 856if ((log_extra_selector & LX_tls_certificate_verified) != 0 &&
817d9f57 857 tls_in.cipher != NULL)
b4ed4da0 858 s = string_append(s, &size, &ptr, 2, US" CV=",
817d9f57
JH
859 tls_in.certificate_verified? "yes":"no");
860if ((log_extra_selector & LX_tls_peerdn) != 0 && tls_in.peerdn != NULL)
48ed62d9 861 s = string_append(s, &size, &ptr, 3, US" DN=\"",
817d9f57
JH
862 string_printing(tls_in.peerdn), US"\"");
863if ((log_extra_selector & LX_tls_sni) != 0 && tls_in.sni != NULL)
3f0945ff 864 s = string_append(s, &size, &ptr, 3, US" SNI=\"",
817d9f57 865 string_printing(tls_in.sni), US"\"");
3f0945ff 866#endif
b4ed4da0
PH
867
868sep = (smtp_connection_had[SMTP_HBUFF_SIZE-1] != SCH_NONE)?
869 US" C=..." : US" C=";
870for (i = smtp_ch_index; i < SMTP_HBUFF_SIZE; i++)
871 {
872 if (smtp_connection_had[i] != SCH_NONE)
873 {
874 s = string_append(s, &size, &ptr, 2, sep,
875 smtp_names[smtp_connection_had[i]]);
876 sep = US",";
877 }
878 }
879
880for (i = 0; i < smtp_ch_index; i++)
881 {
882 s = string_append(s, &size, &ptr, 2, sep, smtp_names[smtp_connection_had[i]]);
883 sep = US",";
884 }
885
886if (s != NULL) s[ptr] = 0; else s = US"";
887log_write(0, LOG_MAIN, "no MAIL in SMTP connection from %s D=%s%s",
888 host_and_ident(FALSE),
889 readconf_printtime(time(NULL) - smtp_connection_start), s);
890}
891
892
893
894/*************************************************
059ec3d9
PH
895* Check HELO line and set sender_helo_name *
896*************************************************/
897
898/* Check the format of a HELO line. The data for HELO/EHLO is supposed to be
899the domain name of the sending host, or an ip literal in square brackets. The
900arrgument is placed in sender_helo_name, which is in malloc store, because it
901must persist over multiple incoming messages. If helo_accept_junk is set, this
902host is permitted to send any old junk (needed for some broken hosts).
903Otherwise, helo_allow_chars can be used for rogue characters in general
904(typically people want to let in underscores).
905
906Argument:
907 s the data portion of the line (already past any white space)
908
909Returns: TRUE or FALSE
910*/
911
912static BOOL
913check_helo(uschar *s)
914{
915uschar *start = s;
916uschar *end = s + Ustrlen(s);
917BOOL yield = helo_accept_junk;
918
919/* Discard any previous helo name */
920
921if (sender_helo_name != NULL)
922 {
923 store_free(sender_helo_name);
924 sender_helo_name = NULL;
925 }
926
927/* Skip tests if junk is permitted. */
928
929if (!yield)
930 {
931 /* Allow the new standard form for IPv6 address literals, namely,
932 [IPv6:....], and because someone is bound to use it, allow an equivalent
933 IPv4 form. Allow plain addresses as well. */
934
935 if (*s == '[')
936 {
937 if (end[-1] == ']')
938 {
939 end[-1] = 0;
940 if (strncmpic(s, US"[IPv6:", 6) == 0)
941 yield = (string_is_ip_address(s+6, NULL) == 6);
942 else if (strncmpic(s, US"[IPv4:", 6) == 0)
943 yield = (string_is_ip_address(s+6, NULL) == 4);
944 else
945 yield = (string_is_ip_address(s+1, NULL) != 0);
946 end[-1] = ']';
947 }
948 }
949
950 /* Non-literals must be alpha, dot, hyphen, plus any non-valid chars
951 that have been configured (usually underscore - sigh). */
952
953 else if (*s != 0)
954 {
955 yield = TRUE;
956 while (*s != 0)
957 {
958 if (!isalnum(*s) && *s != '.' && *s != '-' &&
959 Ustrchr(helo_allow_chars, *s) == NULL)
960 {
961 yield = FALSE;
962 break;
963 }
964 s++;
965 }
966 }
967 }
968
969/* Save argument if OK */
970
971if (yield) sender_helo_name = string_copy_malloc(start);
972return yield;
973}
974
975
976
977
978
979/*************************************************
980* Extract SMTP command option *
981*************************************************/
982
ca86f471 983/* This function picks the next option setting off the end of smtp_cmd_data. It
059ec3d9
PH
984is called for MAIL FROM and RCPT TO commands, to pick off the optional ESMTP
985things that can appear there.
986
987Arguments:
988 name point this at the name
989 value point this at the data string
990
991Returns: TRUE if found an option
992*/
993
994static BOOL
995extract_option(uschar **name, uschar **value)
996{
997uschar *n;
ca86f471 998uschar *v = smtp_cmd_data + Ustrlen(smtp_cmd_data) - 1;
059ec3d9
PH
999while (isspace(*v)) v--;
1000v[1] = 0;
1001
ca86f471 1002while (v > smtp_cmd_data && *v != '=' && !isspace(*v)) v--;
059ec3d9
PH
1003if (*v != '=') return FALSE;
1004
1005n = v;
1006while(isalpha(n[-1])) n--;
1007
7db8d074
PP
1008/* RFC says SP, but TAB seen in wild and other major MTAs accept it */
1009if (!isspace(n[-1])) return FALSE;
059ec3d9
PH
1010
1011n[-1] = 0;
1012*name = n;
1013*v++ = 0;
1014*value = v;
1015return TRUE;
1016}
1017
1018
1019
1020
1021
059ec3d9
PH
1022/*************************************************
1023* Reset for new message *
1024*************************************************/
1025
1026/* This function is called whenever the SMTP session is reset from
1027within either of the setup functions.
1028
1029Argument: the stacking pool storage reset point
1030Returns: nothing
1031*/
1032
1033static void
1034smtp_reset(void *reset_point)
1035{
059ec3d9
PH
1036store_reset(reset_point);
1037recipients_list = NULL;
1038rcpt_count = rcpt_defer_count = rcpt_fail_count =
1039 raw_recipients_count = recipients_count = recipients_list_max = 0;
2e5b33cd 1040cancel_cutthrough_connection("smtp reset");
2e0c1448 1041message_linecount = 0;
059ec3d9 1042message_size = -1;
71fafd95 1043acl_added_headers = NULL;
e7568d51 1044acl_removed_headers = NULL;
059ec3d9 1045queue_only_policy = FALSE;
2679d413
PH
1046rcpt_smtp_response = NULL;
1047rcpt_smtp_response_same = TRUE;
1048rcpt_in_progress = FALSE;
69358f02 1049deliver_freeze = FALSE; /* Can be set by ACL */
6a3f1455 1050freeze_tell = freeze_tell_config; /* Can be set by ACL */
29aba418 1051fake_response = OK; /* Can be set by ACL */
6951ac6c 1052#ifdef WITH_CONTENT_SCAN
8523533c
TK
1053no_mbox_unspool = FALSE; /* Can be set by ACL */
1054#endif
69358f02 1055submission_mode = FALSE; /* Can be set by ACL */
f4ee74ac 1056suppress_local_fixups = suppress_local_fixups_default; /* Can be set by ACL */
69358f02
PH
1057active_local_from_check = local_from_check; /* Can be set by ACL */
1058active_local_sender_retain = local_sender_retain; /* Can be set by ACL */
059ec3d9 1059sender_address = NULL;
2fe1a124 1060submission_name = NULL; /* Can be set by ACL */
059ec3d9
PH
1061raw_sender = NULL; /* After SMTP rewrite, before qualifying */
1062sender_address_unrewritten = NULL; /* Set only after verify rewrite */
1063sender_verified_list = NULL; /* No senders verified */
1064memset(sender_address_cache, 0, sizeof(sender_address_cache));
1065memset(sender_domain_cache, 0, sizeof(sender_domain_cache));
1066authenticated_sender = NULL;
8523533c
TK
1067#ifdef EXPERIMENTAL_BRIGHTMAIL
1068bmi_run = 0;
1069bmi_verdicts = NULL;
1070#endif
80a47a2c 1071#ifndef DISABLE_DKIM
9e5d6b55 1072dkim_signers = NULL;
80a47a2c
TK
1073dkim_disable_verify = FALSE;
1074dkim_collect_input = FALSE;
f7572e5a 1075#endif
8523533c
TK
1076#ifdef EXPERIMENTAL_SPF
1077spf_header_comment = NULL;
1078spf_received = NULL;
8e669ac1 1079spf_result = NULL;
8523533c
TK
1080spf_smtp_comment = NULL;
1081#endif
059ec3d9
PH
1082body_linecount = body_zerocount = 0;
1083
870f6ba8
TF
1084sender_rate = sender_rate_limit = sender_rate_period = NULL;
1085ratelimiters_mail = NULL; /* Updated by ratelimit ACL condition */
1086 /* Note that ratelimiters_conn persists across resets. */
1087
38a0a95f 1088/* Reset message ACL variables */
47ca6d6c 1089
38a0a95f 1090acl_var_m = NULL;
059ec3d9
PH
1091
1092/* The message body variables use malloc store. They may be set if this is
1093not the first message in an SMTP session and the previous message caused them
1094to be referenced in an ACL. */
1095
1096if (message_body != NULL)
1097 {
1098 store_free(message_body);
1099 message_body = NULL;
1100 }
1101
1102if (message_body_end != NULL)
1103 {
1104 store_free(message_body_end);
1105 message_body_end = NULL;
1106 }
1107
1108/* Warning log messages are also saved in malloc store. They are saved to avoid
1109repetition in the same message, but it seems right to repeat them for different
4e88a19f 1110messages. */
059ec3d9
PH
1111
1112while (acl_warn_logged != NULL)
1113 {
1114 string_item *this = acl_warn_logged;
1115 acl_warn_logged = acl_warn_logged->next;
1116 store_free(this);
1117 }
1118}
1119
1120
1121
1122
1123
1124/*************************************************
1125* Initialize for incoming batched SMTP message *
1126*************************************************/
1127
1128/* This function is called from smtp_setup_msg() in the case when
1129smtp_batched_input is true. This happens when -bS is used to pass a whole batch
1130of messages in one file with SMTP commands between them. All errors must be
1131reported by sending a message, and only MAIL FROM, RCPT TO, and DATA are
1132relevant. After an error on a sender, or an invalid recipient, the remainder
1133of the message is skipped. The value of received_protocol is already set.
1134
1135Argument: none
1136Returns: > 0 message successfully started (reached DATA)
1137 = 0 QUIT read or end of file reached
1138 < 0 should not occur
1139*/
1140
1141static int
1142smtp_setup_batch_msg(void)
1143{
1144int done = 0;
1145void *reset_point = store_get(0);
1146
1147/* Save the line count at the start of each transaction - single commands
1148like HELO and RSET count as whole transactions. */
1149
1150bsmtp_transaction_linecount = receive_linecount;
1151
1152if ((receive_feof)()) return 0; /* Treat EOF as QUIT */
1153
1154smtp_reset(reset_point); /* Reset for start of message */
1155
1156/* Deal with SMTP commands. This loop is exited by setting done to a POSITIVE
1157value. The values are 2 larger than the required yield of the function. */
1158
1159while (done <= 0)
1160 {
1161 uschar *errmess;
1162 uschar *recipient = NULL;
1163 int start, end, sender_domain, recipient_domain;
1164
1165 switch(smtp_read_command(FALSE))
1166 {
1167 /* The HELO/EHLO commands set sender_address_helo if they have
1168 valid data; otherwise they are ignored, except that they do
1169 a reset of the state. */
1170
1171 case HELO_CMD:
1172 case EHLO_CMD:
1173
ca86f471 1174 check_helo(smtp_cmd_data);
059ec3d9
PH
1175 /* Fall through */
1176
1177 case RSET_CMD:
1178 smtp_reset(reset_point);
1179 bsmtp_transaction_linecount = receive_linecount;
1180 break;
1181
1182
1183 /* The MAIL FROM command requires an address as an operand. All we
1184 do here is to parse it for syntactic correctness. The form "<>" is
1185 a special case which converts into an empty string. The start/end
1186 pointers in the original are not used further for this address, as
1187 it is the canonical extracted address which is all that is kept. */
1188
1189 case MAIL_CMD:
1190 if (sender_address != NULL)
1191 /* The function moan_smtp_batch() does not return. */
3ee512ff 1192 moan_smtp_batch(smtp_cmd_buffer, "503 Sender already given");
059ec3d9 1193
ca86f471 1194 if (smtp_cmd_data[0] == 0)
059ec3d9 1195 /* The function moan_smtp_batch() does not return. */
3ee512ff 1196 moan_smtp_batch(smtp_cmd_buffer, "501 MAIL FROM must have an address operand");
059ec3d9
PH
1197
1198 /* Reset to start of message */
1199
1200 smtp_reset(reset_point);
1201
1202 /* Apply SMTP rewrite */
1203
1204 raw_sender = ((rewrite_existflags & rewrite_smtp) != 0)?
ca86f471
PH
1205 rewrite_one(smtp_cmd_data, rewrite_smtp|rewrite_smtp_sender, NULL, FALSE,
1206 US"", global_rewrite_rules) : smtp_cmd_data;
059ec3d9
PH
1207
1208 /* Extract the address; the TRUE flag allows <> as valid */
1209
1210 raw_sender =
1211 parse_extract_address(raw_sender, &errmess, &start, &end, &sender_domain,
1212 TRUE);
1213
1214 if (raw_sender == NULL)
1215 /* The function moan_smtp_batch() does not return. */
3ee512ff 1216 moan_smtp_batch(smtp_cmd_buffer, "501 %s", errmess);
059ec3d9
PH
1217
1218 sender_address = string_copy(raw_sender);
1219
1220 /* Qualify unqualified sender addresses if permitted to do so. */
1221
1222 if (sender_domain == 0 && sender_address[0] != 0 && sender_address[0] != '@')
1223 {
1224 if (allow_unqualified_sender)
1225 {
1226 sender_address = rewrite_address_qualify(sender_address, FALSE);
1227 DEBUG(D_receive) debug_printf("unqualified address %s accepted "
1228 "and rewritten\n", raw_sender);
1229 }
1230 /* The function moan_smtp_batch() does not return. */
3ee512ff 1231 else moan_smtp_batch(smtp_cmd_buffer, "501 sender address must contain "
059ec3d9
PH
1232 "a domain");
1233 }
1234 break;
1235
1236
1237 /* The RCPT TO command requires an address as an operand. All we do
1238 here is to parse it for syntactic correctness. There may be any number
1239 of RCPT TO commands, specifying multiple senders. We build them all into
1240 a data structure that is in argc/argv format. The start/end values
1241 given by parse_extract_address are not used, as we keep only the
1242 extracted address. */
1243
1244 case RCPT_CMD:
1245 if (sender_address == NULL)
1246 /* The function moan_smtp_batch() does not return. */
3ee512ff 1247 moan_smtp_batch(smtp_cmd_buffer, "503 No sender yet given");
059ec3d9 1248
ca86f471 1249 if (smtp_cmd_data[0] == 0)
059ec3d9 1250 /* The function moan_smtp_batch() does not return. */
3ee512ff 1251 moan_smtp_batch(smtp_cmd_buffer, "501 RCPT TO must have an address operand");
059ec3d9
PH
1252
1253 /* Check maximum number allowed */
1254
1255 if (recipients_max > 0 && recipients_count + 1 > recipients_max)
1256 /* The function moan_smtp_batch() does not return. */
3ee512ff 1257 moan_smtp_batch(smtp_cmd_buffer, "%s too many recipients",
059ec3d9
PH
1258 recipients_max_reject? "552": "452");
1259
1260 /* Apply SMTP rewrite, then extract address. Don't allow "<>" as a
1261 recipient address */
1262
1263 recipient = ((rewrite_existflags & rewrite_smtp) != 0)?
ca86f471
PH
1264 rewrite_one(smtp_cmd_data, rewrite_smtp, NULL, FALSE, US"",
1265 global_rewrite_rules) : smtp_cmd_data;
059ec3d9
PH
1266
1267 /* rfc821_domains = TRUE; << no longer needed */
1268 recipient = parse_extract_address(recipient, &errmess, &start, &end,
1269 &recipient_domain, FALSE);
1270 /* rfc821_domains = FALSE; << no longer needed */
1271
1272 if (recipient == NULL)
1273 /* The function moan_smtp_batch() does not return. */
3ee512ff 1274 moan_smtp_batch(smtp_cmd_buffer, "501 %s", errmess);
059ec3d9
PH
1275
1276 /* If the recipient address is unqualified, qualify it if permitted. Then
1277 add it to the list of recipients. */
1278
1279 if (recipient_domain == 0)
1280 {
1281 if (allow_unqualified_recipient)
1282 {
1283 DEBUG(D_receive) debug_printf("unqualified address %s accepted\n",
1284 recipient);
1285 recipient = rewrite_address_qualify(recipient, TRUE);
1286 }
1287 /* The function moan_smtp_batch() does not return. */
3ee512ff 1288 else moan_smtp_batch(smtp_cmd_buffer, "501 recipient address must contain "
059ec3d9
PH
1289 "a domain");
1290 }
1291 receive_add_recipient(recipient, -1);
1292 break;
1293
1294
1295 /* The DATA command is legal only if it follows successful MAIL FROM
1296 and RCPT TO commands. This function is complete when a valid DATA
1297 command is encountered. */
1298
1299 case DATA_CMD:
1300 if (sender_address == NULL || recipients_count <= 0)
1301 {
1302 /* The function moan_smtp_batch() does not return. */
1303 if (sender_address == NULL)
3ee512ff 1304 moan_smtp_batch(smtp_cmd_buffer,
059ec3d9
PH
1305 "503 MAIL FROM:<sender> command must precede DATA");
1306 else
3ee512ff 1307 moan_smtp_batch(smtp_cmd_buffer,
059ec3d9
PH
1308 "503 RCPT TO:<recipient> must precede DATA");
1309 }
1310 else
1311 {
1312 done = 3; /* DATA successfully achieved */
1313 message_ended = END_NOTENDED; /* Indicate in middle of message */
1314 }
1315 break;
1316
1317
1318 /* The VRFY, EXPN, HELP, ETRN, and NOOP commands are ignored. */
1319
1320 case VRFY_CMD:
1321 case EXPN_CMD:
1322 case HELP_CMD:
1323 case NOOP_CMD:
1324 case ETRN_CMD:
1325 bsmtp_transaction_linecount = receive_linecount;
1326 break;
1327
1328
1329 case EOF_CMD:
1330 case QUIT_CMD:
1331 done = 2;
1332 break;
1333
1334
1335 case BADARG_CMD:
1336 /* The function moan_smtp_batch() does not return. */
3ee512ff 1337 moan_smtp_batch(smtp_cmd_buffer, "501 Unexpected argument data");
059ec3d9
PH
1338 break;
1339
1340
1341 case BADCHAR_CMD:
1342 /* The function moan_smtp_batch() does not return. */
3ee512ff 1343 moan_smtp_batch(smtp_cmd_buffer, "501 Unexpected NULL in SMTP command");
059ec3d9
PH
1344 break;
1345
1346
1347 default:
1348 /* The function moan_smtp_batch() does not return. */
3ee512ff 1349 moan_smtp_batch(smtp_cmd_buffer, "500 Command unrecognized");
059ec3d9
PH
1350 break;
1351 }
1352 }
1353
1354return done - 2; /* Convert yield values */
1355}
1356
1357
1358
1359
1360/*************************************************
1361* Start an SMTP session *
1362*************************************************/
1363
1364/* This function is called at the start of an SMTP session. Thereafter,
1365smtp_setup_msg() is called to initiate each separate message. This
1366function does host-specific testing, and outputs the banner line.
1367
1368Arguments: none
1369Returns: FALSE if the session can not continue; something has
1370 gone wrong, or the connection to the host is blocked
1371*/
1372
1373BOOL
1374smtp_start_session(void)
1375{
1376int size = 256;
4e88a19f
PH
1377int ptr, esclen;
1378uschar *user_msg, *log_msg;
1379uschar *code, *esc;
059ec3d9
PH
1380uschar *p, *s, *ss;
1381
b4ed4da0
PH
1382smtp_connection_start = time(NULL);
1383for (smtp_ch_index = 0; smtp_ch_index < SMTP_HBUFF_SIZE; smtp_ch_index++)
1384 smtp_connection_had[smtp_ch_index] = SCH_NONE;
1385smtp_ch_index = 0;
1386
00f00ca5
PH
1387/* Default values for certain variables */
1388
059ec3d9 1389helo_seen = esmtp = helo_accept_junk = FALSE;
b4ed4da0 1390smtp_mailcmd_count = 0;
059ec3d9
PH
1391count_nonmail = TRUE_UNSET;
1392synprot_error_count = unknown_command_count = nonmail_command_count = 0;
1393smtp_delay_mail = smtp_rlm_base;
1394auth_advertised = FALSE;
1395pipelining_advertised = FALSE;
cf8b11a5 1396pipelining_enable = TRUE;
059ec3d9 1397sync_cmd_limit = NON_SYNC_CMD_NON_PIPELINING;
8f128379 1398smtp_exit_function_called = FALSE; /* For avoiding loop in not-quit exit */
059ec3d9
PH
1399
1400memset(sender_host_cache, 0, sizeof(sender_host_cache));
1401
33d73e3b
PH
1402/* If receiving by -bs from a trusted user, or testing with -bh, we allow
1403authentication settings from -oMaa to remain in force. */
1404
1405if (!host_checking && !sender_host_notsocket) sender_host_authenticated = NULL;
059ec3d9
PH
1406authenticated_by = NULL;
1407
1408#ifdef SUPPORT_TLS
817d9f57 1409tls_in.cipher = tls_in.peerdn = NULL;
059ec3d9
PH
1410tls_advertised = FALSE;
1411#endif
1412
1413/* Reset ACL connection variables */
1414
38a0a95f 1415acl_var_c = NULL;
059ec3d9 1416
ca86f471 1417/* Allow for trailing 0 in the command and data buffers. */
3ee512ff 1418
ca86f471 1419smtp_cmd_buffer = (uschar *)malloc(2*smtp_cmd_buffer_size + 2);
3ee512ff 1420if (smtp_cmd_buffer == NULL)
059ec3d9
PH
1421 log_write(0, LOG_MAIN|LOG_PANIC_DIE,
1422 "malloc() failed for SMTP command buffer");
2416c261 1423smtp_cmd_buffer[0] = 0;
ca86f471 1424smtp_data_buffer = smtp_cmd_buffer + smtp_cmd_buffer_size + 1;
059ec3d9
PH
1425
1426/* For batched input, the protocol setting can be overridden from the
1427command line by a trusted caller. */
1428
1429if (smtp_batched_input)
1430 {
1431 if (received_protocol == NULL) received_protocol = US"local-bsmtp";
1432 }
1433
1434/* For non-batched SMTP input, the protocol setting is forced here. It will be
1435reset later if any of EHLO/AUTH/STARTTLS are received. */
1436
1437else
1438 received_protocol =
1439 protocols[pnormal] + ((sender_host_address != NULL)? pnlocal : 0);
1440
1441/* Set up the buffer for inputting using direct read() calls, and arrange to
1442call the local functions instead of the standard C ones. */
1443
1444smtp_inbuffer = (uschar *)malloc(in_buffer_size);
1445if (smtp_inbuffer == NULL)
1446 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "malloc() failed for SMTP input buffer");
1447receive_getc = smtp_getc;
1448receive_ungetc = smtp_ungetc;
1449receive_feof = smtp_feof;
1450receive_ferror = smtp_ferror;
58eb016e 1451receive_smtp_buffered = smtp_buffered;
059ec3d9
PH
1452smtp_inptr = smtp_inend = smtp_inbuffer;
1453smtp_had_eof = smtp_had_error = 0;
1454
1455/* Set up the message size limit; this may be host-specific */
1456
d45b1de8
PH
1457thismessage_size_limit = expand_string_integer(message_size_limit, TRUE);
1458if (expand_string_message != NULL)
059ec3d9
PH
1459 {
1460 if (thismessage_size_limit == -1)
1461 log_write(0, LOG_MAIN|LOG_PANIC, "unable to expand message_size_limit: "
1462 "%s", expand_string_message);
1463 else
1464 log_write(0, LOG_MAIN|LOG_PANIC, "invalid message_size_limit: "
1465 "%s", expand_string_message);
1466 smtp_closedown(US"Temporary local problem - please try later");
1467 return FALSE;
1468 }
1469
1470/* When a message is input locally via the -bs or -bS options, sender_host_
1471unknown is set unless -oMa was used to force an IP address, in which case it
1472is checked like a real remote connection. When -bs is used from inetd, this
1473flag is not set, causing the sending host to be checked. The code that deals
1474with IP source routing (if configured) is never required for -bs or -bS and
1475the flag sender_host_notsocket is used to suppress it.
1476
1477If smtp_accept_max and smtp_accept_reserve are set, keep some connections in
1478reserve for certain hosts and/or networks. */
1479
1480if (!sender_host_unknown)
1481 {
1482 int rc;
1483 BOOL reserved_host = FALSE;
1484
1485 /* Look up IP options (source routing info) on the socket if this is not an
1486 -oMa "host", and if any are found, log them and drop the connection.
1487
1488 Linux (and others now, see below) is different to everyone else, so there
1489 has to be some conditional compilation here. Versions of Linux before 2.1.15
1490 used a structure whose name was "options". Somebody finally realized that
1491 this name was silly, and it got changed to "ip_options". I use the
1492 newer name here, but there is a fudge in the script that sets up os.h
1493 to define a macro in older Linux systems.
1494
1495 Sigh. Linux is a fast-moving target. Another generation of Linux uses
1496 glibc 2, which has chosen ip_opts for the structure name. This is now
1497 really a glibc thing rather than a Linux thing, so the condition name
1498 has been changed to reflect this. It is relevant also to GNU/Hurd.
1499
1500 Mac OS 10.x (Darwin) is like the later glibc versions, but without the
1501 setting of the __GLIBC__ macro, so we can't detect it automatically. There's
1502 a special macro defined in the os.h file.
1503
1504 Some DGUX versions on older hardware appear not to support IP options at
1505 all, so there is now a general macro which can be set to cut out this
1506 support altogether.
1507
1508 How to do this properly in IPv6 is not yet known. */
1509
1510 #if !HAVE_IPV6 && !defined(NO_IP_OPTIONS)
1511
1512 #ifdef GLIBC_IP_OPTIONS
1513 #if (!defined __GLIBC__) || (__GLIBC__ < 2)
1514 #define OPTSTYLE 1
1515 #else
1516 #define OPTSTYLE 2
1517 #endif
1518 #elif defined DARWIN_IP_OPTIONS
1519 #define OPTSTYLE 2
1520 #else
1521 #define OPTSTYLE 3
1522 #endif
1523
1524 if (!host_checking && !sender_host_notsocket)
1525 {
1526 #if OPTSTYLE == 1
36a3b041 1527 EXIM_SOCKLEN_T optlen = sizeof(struct ip_options) + MAX_IPOPTLEN;
059ec3d9
PH
1528 struct ip_options *ipopt = store_get(optlen);
1529 #elif OPTSTYLE == 2
1530 struct ip_opts ipoptblock;
1531 struct ip_opts *ipopt = &ipoptblock;
36a3b041 1532 EXIM_SOCKLEN_T optlen = sizeof(ipoptblock);
059ec3d9
PH
1533 #else
1534 struct ipoption ipoptblock;
1535 struct ipoption *ipopt = &ipoptblock;
36a3b041 1536 EXIM_SOCKLEN_T optlen = sizeof(ipoptblock);
059ec3d9
PH
1537 #endif
1538
1539 /* Occasional genuine failures of getsockopt() have been seen - for
1540 example, "reset by peer". Therefore, just log and give up on this
1541 call, unless the error is ENOPROTOOPT. This error is given by systems
1542 that have the interfaces but not the mechanism - e.g. GNU/Hurd at the time
1543 of writing. So for that error, carry on - we just can't do an IP options
1544 check. */
1545
1546 DEBUG(D_receive) debug_printf("checking for IP options\n");
1547
1548 if (getsockopt(fileno(smtp_out), IPPROTO_IP, IP_OPTIONS, (uschar *)(ipopt),
1549 &optlen) < 0)
1550 {
1551 if (errno != ENOPROTOOPT)
1552 {
1553 log_write(0, LOG_MAIN, "getsockopt() failed from %s: %s",
1554 host_and_ident(FALSE), strerror(errno));
1555 smtp_printf("451 SMTP service not available\r\n");
1556 return FALSE;
1557 }
1558 }
1559
1560 /* Deal with any IP options that are set. On the systems I have looked at,
1561 the value of MAX_IPOPTLEN has been 40, meaning that there should never be
1562 more logging data than will fit in big_buffer. Nevertheless, after somebody
1563 questioned this code, I've added in some paranoid checking. */
1564
1565 else if (optlen > 0)
1566 {
1567 uschar *p = big_buffer;
1568 uschar *pend = big_buffer + big_buffer_size;
1569 uschar *opt, *adptr;
1570 int optcount;
1571 struct in_addr addr;
1572
1573 #if OPTSTYLE == 1
1574 uschar *optstart = (uschar *)(ipopt->__data);
1575 #elif OPTSTYLE == 2
1576 uschar *optstart = (uschar *)(ipopt->ip_opts);
1577 #else
1578 uschar *optstart = (uschar *)(ipopt->ipopt_list);
1579 #endif
1580
1581 DEBUG(D_receive) debug_printf("IP options exist\n");
1582
1583 Ustrcpy(p, "IP options on incoming call:");
1584 p += Ustrlen(p);
1585
1586 for (opt = optstart; opt != NULL &&
1587 opt < (uschar *)(ipopt) + optlen;)
1588 {
1589 switch (*opt)
1590 {
1591 case IPOPT_EOL:
1592 opt = NULL;
1593 break;
1594
1595 case IPOPT_NOP:
1596 opt++;
1597 break;
1598
1599 case IPOPT_SSRR:
1600 case IPOPT_LSRR:
1601 if (!string_format(p, pend-p, " %s [@%s",
1602 (*opt == IPOPT_SSRR)? "SSRR" : "LSRR",
1603 #if OPTSTYLE == 1
1604 inet_ntoa(*((struct in_addr *)(&(ipopt->faddr))))))
1605 #elif OPTSTYLE == 2
1606 inet_ntoa(ipopt->ip_dst)))
1607 #else
1608 inet_ntoa(ipopt->ipopt_dst)))
1609 #endif
1610 {
1611 opt = NULL;
1612 break;
1613 }
1614
1615 p += Ustrlen(p);
1616 optcount = (opt[1] - 3) / sizeof(struct in_addr);
1617 adptr = opt + 3;
1618 while (optcount-- > 0)
1619 {
1620 memcpy(&addr, adptr, sizeof(addr));
1621 if (!string_format(p, pend - p - 1, "%s%s",
1622 (optcount == 0)? ":" : "@", inet_ntoa(addr)))
1623 {
1624 opt = NULL;
1625 break;
1626 }
1627 p += Ustrlen(p);
1628 adptr += sizeof(struct in_addr);
1629 }
1630 *p++ = ']';
1631 opt += opt[1];
1632 break;
1633
1634 default:
1635 {
1636 int i;
1637 if (pend - p < 4 + 3*opt[1]) { opt = NULL; break; }
1638 Ustrcat(p, "[ ");
1639 p += 2;
1640 for (i = 0; i < opt[1]; i++)
1641 {
1642 sprintf(CS p, "%2.2x ", opt[i]);
1643 p += 3;
1644 }
1645 *p++ = ']';
1646 }
1647 opt += opt[1];
1648 break;
1649 }
1650 }
1651
1652 *p = 0;
1653 log_write(0, LOG_MAIN, "%s", big_buffer);
1654
1655 /* Refuse any call with IP options. This is what tcpwrappers 7.5 does. */
1656
1657 log_write(0, LOG_MAIN|LOG_REJECT,
1658 "connection from %s refused (IP options)", host_and_ident(FALSE));
1659
1660 smtp_printf("554 SMTP service not available\r\n");
1661 return FALSE;
1662 }
1663
1664 /* Length of options = 0 => there are no options */
1665
1666 else DEBUG(D_receive) debug_printf("no IP options found\n");
1667 }
1668 #endif /* HAVE_IPV6 && !defined(NO_IP_OPTIONS) */
1669
1670 /* Set keep-alive in socket options. The option is on by default. This
1671 setting is an attempt to get rid of some hanging connections that stick in
1672 read() when the remote end (usually a dialup) goes away. */
1673
1674 if (smtp_accept_keepalive && !sender_host_notsocket)
1675 ip_keepalive(fileno(smtp_out), sender_host_address, FALSE);
1676
1677 /* If the current host matches host_lookup, set the name by doing a
1678 reverse lookup. On failure, sender_host_name will be NULL and
1679 host_lookup_failed will be TRUE. This may or may not be serious - optional
1680 checks later. */
1681
1682 if (verify_check_host(&host_lookup) == OK)
1683 {
1684 (void)host_name_lookup();
1685 host_build_sender_fullhost();
1686 }
1687
1688 /* Delay this until we have the full name, if it is looked up. */
1689
1690 set_process_info("handling incoming connection from %s",
1691 host_and_ident(FALSE));
1692
1693 /* Start up TLS if tls_on_connect is set. This is for supporting the legacy
1694 smtps port for use with older style SSL MTAs. */
1695
1696 #ifdef SUPPORT_TLS
817d9f57 1697 if (tls_in.on_connect && tls_server_start(tls_require_ciphers) != OK)
059ec3d9
PH
1698 return FALSE;
1699 #endif
1700
1701 /* Test for explicit connection rejection */
1702
1703 if (verify_check_host(&host_reject_connection) == OK)
1704 {
1705 log_write(L_connection_reject, LOG_MAIN|LOG_REJECT, "refused connection "
1706 "from %s (host_reject_connection)", host_and_ident(FALSE));
1707 smtp_printf("554 SMTP service not available\r\n");
1708 return FALSE;
1709 }
1710
afb3eaaf
PH
1711 /* Test with TCP Wrappers if so configured. There is a problem in that
1712 hosts_ctl() returns 0 (deny) under a number of system failure circumstances,
1713 such as disks dying. In these cases, it is desirable to reject with a 4xx
1714 error instead of a 5xx error. There isn't a "right" way to detect such
1715 problems. The following kludge is used: errno is zeroed before calling
1716 hosts_ctl(). If the result is "reject", a 5xx error is given only if the
1717 value of errno is 0 or ENOENT (which happens if /etc/hosts.{allow,deny} does
1718 not exist). */
059ec3d9
PH
1719
1720 #ifdef USE_TCP_WRAPPERS
afb3eaaf 1721 errno = 0;
5dc43717
JJ
1722 tcp_wrappers_name = expand_string(tcp_wrappers_daemon_name);
1723 if (tcp_wrappers_name == NULL)
1724 {
1725 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "Expansion of \"%s\" "
1726 "(tcp_wrappers_name) failed: %s", string_printing(tcp_wrappers_name),
1727 expand_string_message);
1728 }
1729 if (!hosts_ctl(tcp_wrappers_name,
059ec3d9
PH
1730 (sender_host_name == NULL)? STRING_UNKNOWN : CS sender_host_name,
1731 (sender_host_address == NULL)? STRING_UNKNOWN : CS sender_host_address,
1732 (sender_ident == NULL)? STRING_UNKNOWN : CS sender_ident))
1733 {
afb3eaaf
PH
1734 if (errno == 0 || errno == ENOENT)
1735 {
1736 HDEBUG(D_receive) debug_printf("tcp wrappers rejection\n");
1737 log_write(L_connection_reject,
1738 LOG_MAIN|LOG_REJECT, "refused connection from %s "
1739 "(tcp wrappers)", host_and_ident(FALSE));
1740 smtp_printf("554 SMTP service not available\r\n");
1741 }
1742 else
1743 {
1744 int save_errno = errno;
1745 HDEBUG(D_receive) debug_printf("tcp wrappers rejected with unexpected "
1746 "errno value %d\n", save_errno);
1747 log_write(L_connection_reject,
1748 LOG_MAIN|LOG_REJECT, "temporarily refused connection from %s "
1749 "(tcp wrappers errno=%d)", host_and_ident(FALSE), save_errno);
1750 smtp_printf("451 Temporary local problem - please try later\r\n");
1751 }
059ec3d9
PH
1752 return FALSE;
1753 }
1754 #endif
1755
b01dd148
PH
1756 /* Check for reserved slots. The value of smtp_accept_count has already been
1757 incremented to include this process. */
059ec3d9
PH
1758
1759 if (smtp_accept_max > 0 &&
b01dd148 1760 smtp_accept_count > smtp_accept_max - smtp_accept_reserve)
059ec3d9
PH
1761 {
1762 if ((rc = verify_check_host(&smtp_reserve_hosts)) != OK)
1763 {
1764 log_write(L_connection_reject,
1765 LOG_MAIN, "temporarily refused connection from %s: not in "
1766 "reserve list: connected=%d max=%d reserve=%d%s",
b01dd148 1767 host_and_ident(FALSE), smtp_accept_count - 1, smtp_accept_max,
059ec3d9
PH
1768 smtp_accept_reserve, (rc == DEFER)? " (lookup deferred)" : "");
1769 smtp_printf("421 %s: Too many concurrent SMTP connections; "
1770 "please try again later\r\n", smtp_active_hostname);
1771 return FALSE;
1772 }
1773 reserved_host = TRUE;
1774 }
1775
1776 /* If a load level above which only messages from reserved hosts are
1777 accepted is set, check the load. For incoming calls via the daemon, the
1778 check is done in the superior process if there are no reserved hosts, to
1779 save a fork. In all cases, the load average will already be available
1780 in a global variable at this point. */
1781
1782 if (smtp_load_reserve >= 0 &&
1783 load_average > smtp_load_reserve &&
1784 !reserved_host &&
1785 verify_check_host(&smtp_reserve_hosts) != OK)
1786 {
1787 log_write(L_connection_reject,
1788 LOG_MAIN, "temporarily refused connection from %s: not in "
1789 "reserve list and load average = %.2f", host_and_ident(FALSE),
1790 (double)load_average/1000.0);
1791 smtp_printf("421 %s: Too much load; please try again later\r\n",
1792 smtp_active_hostname);
1793 return FALSE;
1794 }
1795
1796 /* Determine whether unqualified senders or recipients are permitted
1797 for this host. Unfortunately, we have to do this every time, in order to
1798 set the flags so that they can be inspected when considering qualifying
1799 addresses in the headers. For a site that permits no qualification, this
1800 won't take long, however. */
1801
1802 allow_unqualified_sender =
1803 verify_check_host(&sender_unqualified_hosts) == OK;
1804
1805 allow_unqualified_recipient =
1806 verify_check_host(&recipient_unqualified_hosts) == OK;
1807
1808 /* Determine whether HELO/EHLO is required for this host. The requirement
1809 can be hard or soft. */
1810
1811 helo_required = verify_check_host(&helo_verify_hosts) == OK;
1812 if (!helo_required)
1813 helo_verify = verify_check_host(&helo_try_verify_hosts) == OK;
1814
1815 /* Determine whether this hosts is permitted to send syntactic junk
1816 after a HELO or EHLO command. */
1817
1818 helo_accept_junk = verify_check_host(&helo_accept_junk_hosts) == OK;
1819 }
1820
1821/* For batch SMTP input we are now done. */
1822
1823if (smtp_batched_input) return TRUE;
1824
1825/* Run the ACL if it exists */
1826
4e88a19f 1827user_msg = NULL;
059ec3d9
PH
1828if (acl_smtp_connect != NULL)
1829 {
1830 int rc;
64ffc24f 1831 rc = acl_check(ACL_WHERE_CONNECT, NULL, acl_smtp_connect, &user_msg,
059ec3d9
PH
1832 &log_msg);
1833 if (rc != OK)
1834 {
1835 (void)smtp_handle_acl_fail(ACL_WHERE_CONNECT, rc, user_msg, log_msg);
1836 return FALSE;
1837 }
1838 }
1839
1840/* Output the initial message for a two-way SMTP connection. It may contain
1841newlines, which then cause a multi-line response to be given. */
1842
4e88a19f
PH
1843code = US"220"; /* Default status code */
1844esc = US""; /* Default extended status code */
1845esclen = 0; /* Length of esc */
1846
1847if (user_msg == NULL)
1848 {
1849 s = expand_string(smtp_banner);
1850 if (s == NULL)
1851 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "Expansion of \"%s\" (smtp_banner) "
1852 "failed: %s", smtp_banner, expand_string_message);
1853 }
1854else
1855 {
1856 int codelen = 3;
1857 s = user_msg;
1858 smtp_message_code(&code, &codelen, &s, NULL);
d6a96edc 1859 if (codelen > 4)
4e88a19f
PH
1860 {
1861 esc = code + 4;
1862 esclen = codelen - 4;
1863 }
1864 }
059ec3d9
PH
1865
1866/* Remove any terminating newlines; might as well remove trailing space too */
1867
1868p = s + Ustrlen(s);
1869while (p > s && isspace(p[-1])) p--;
1870*p = 0;
1871
1872/* It seems that CC:Mail is braindead, and assumes that the greeting message
1873is all contained in a single IP packet. The original code wrote out the
1874greeting using several calls to fprint/fputc, and on busy servers this could
1875cause it to be split over more than one packet - which caused CC:Mail to fall
1876over when it got the second part of the greeting after sending its first
1877command. Sigh. To try to avoid this, build the complete greeting message
1878first, and output it in one fell swoop. This gives a better chance of it
1879ending up as a single packet. */
1880
1881ss = store_get(size);
1882ptr = 0;
1883
1884p = s;
1885do /* At least once, in case we have an empty string */
1886 {
1887 int len;
1888 uschar *linebreak = Ustrchr(p, '\n');
4e88a19f 1889 ss = string_cat(ss, &size, &ptr, code, 3);
059ec3d9
PH
1890 if (linebreak == NULL)
1891 {
1892 len = Ustrlen(p);
4e88a19f 1893 ss = string_cat(ss, &size, &ptr, US" ", 1);
059ec3d9
PH
1894 }
1895 else
1896 {
1897 len = linebreak - p;
4e88a19f 1898 ss = string_cat(ss, &size, &ptr, US"-", 1);
059ec3d9 1899 }
4e88a19f 1900 ss = string_cat(ss, &size, &ptr, esc, esclen);
059ec3d9
PH
1901 ss = string_cat(ss, &size, &ptr, p, len);
1902 ss = string_cat(ss, &size, &ptr, US"\r\n", 2);
1903 p += len;
1904 if (linebreak != NULL) p++;
1905 }
1906while (*p != 0);
1907
1908ss[ptr] = 0; /* string_cat leaves room for this */
1909
1910/* Before we write the banner, check that there is no input pending, unless
1911this synchronisation check is disabled. */
1912
a14e5636 1913if (!check_sync())
059ec3d9 1914 {
a14e5636
PH
1915 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP protocol "
1916 "synchronization error (input sent without waiting for greeting): "
1917 "rejected connection from %s input=\"%s\"", host_and_ident(TRUE),
1918 string_printing(smtp_inptr));
1919 smtp_printf("554 SMTP synchronization error\r\n");
1920 return FALSE;
059ec3d9
PH
1921 }
1922
1923/* Now output the banner */
1924
1925smtp_printf("%s", ss);
1926return TRUE;
1927}
1928
1929
1930
1931
1932
1933/*************************************************
1934* Handle SMTP syntax and protocol errors *
1935*************************************************/
1936
1937/* Write to the log for SMTP syntax errors in incoming commands, if configured
1938to do so. Then transmit the error response. The return value depends on the
1939number of syntax and protocol errors in this SMTP session.
1940
1941Arguments:
1942 type error type, given as a log flag bit
1943 code response code; <= 0 means don't send a response
1944 data data to reflect in the response (can be NULL)
1945 errmess the error message
1946
1947Returns: -1 limit of syntax/protocol errors NOT exceeded
1948 +1 limit of syntax/protocol errors IS exceeded
1949
1950These values fit in with the values of the "done" variable in the main
1951processing loop in smtp_setup_msg(). */
1952
1953static int
1954synprot_error(int type, int code, uschar *data, uschar *errmess)
1955{
1956int yield = -1;
1957
1958log_write(type, LOG_MAIN, "SMTP %s error in \"%s\" %s %s",
1959 (type == L_smtp_syntax_error)? "syntax" : "protocol",
3ee512ff 1960 string_printing(smtp_cmd_buffer), host_and_ident(TRUE), errmess);
059ec3d9
PH
1961
1962if (++synprot_error_count > smtp_max_synprot_errors)
1963 {
1964 yield = 1;
1965 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
1966 "syntax or protocol errors (last command was \"%s\")",
3ee512ff 1967 host_and_ident(FALSE), smtp_cmd_buffer);
059ec3d9
PH
1968 }
1969
1970if (code > 0)
1971 {
1972 smtp_printf("%d%c%s%s%s\r\n", code, (yield == 1)? '-' : ' ',
1973 (data == NULL)? US"" : data, (data == NULL)? US"" : US": ", errmess);
1974 if (yield == 1)
1975 smtp_printf("%d Too many syntax or protocol errors\r\n", code);
1976 }
1977
1978return yield;
1979}
1980
1981
1982
1983
1984/*************************************************
1985* Log incomplete transactions *
1986*************************************************/
1987
1988/* This function is called after a transaction has been aborted by RSET, QUIT,
1989connection drops or other errors. It logs the envelope information received
1990so far in order to preserve address verification attempts.
1991
1992Argument: string to indicate what aborted the transaction
1993Returns: nothing
1994*/
1995
1996static void
1997incomplete_transaction_log(uschar *what)
1998{
1999if (sender_address == NULL || /* No transaction in progress */
2000 (log_write_selector & L_smtp_incomplete_transaction) == 0 /* Not logging */
2001 ) return;
2002
2003/* Build list of recipients for logging */
2004
2005if (recipients_count > 0)
2006 {
2007 int i;
2008 raw_recipients = store_get(recipients_count * sizeof(uschar *));
2009 for (i = 0; i < recipients_count; i++)
2010 raw_recipients[i] = recipients_list[i].address;
2011 raw_recipients_count = recipients_count;
2012 }
2013
2014log_write(L_smtp_incomplete_transaction, LOG_MAIN|LOG_SENDER|LOG_RECIPIENTS,
2015 "%s incomplete transaction (%s)", host_and_ident(TRUE), what);
2016}
2017
2018
2019
2020
2021/*************************************************
2022* Send SMTP response, possibly multiline *
2023*************************************************/
2024
2025/* There are, it seems, broken clients out there that cannot handle multiline
2026responses. If no_multiline_responses is TRUE (it can be set from an ACL), we
2027output nothing for non-final calls, and only the first line for anything else.
2028
2029Arguments:
a5bd321b 2030 code SMTP code, may involve extended status codes
d6a96edc 2031 codelen length of smtp code; if > 4 there's an ESC
059ec3d9
PH
2032 final FALSE if the last line isn't the final line
2033 msg message text, possibly containing newlines
2034
2035Returns: nothing
2036*/
2037
2038void
a5bd321b 2039smtp_respond(uschar* code, int codelen, BOOL final, uschar *msg)
059ec3d9 2040{
a5bd321b
PH
2041int esclen = 0;
2042uschar *esc = US"";
2043
059ec3d9
PH
2044if (!final && no_multiline_responses) return;
2045
d6a96edc 2046if (codelen > 4)
a5bd321b
PH
2047 {
2048 esc = code + 4;
2049 esclen = codelen - 4;
2050 }
2051
2679d413
PH
2052/* If this is the first output for a (non-batch) RCPT command, see if all RCPTs
2053have had the same. Note: this code is also present in smtp_printf(). It would
2054be tidier to have it only in one place, but when it was added, it was easier to
2055do it that way, so as not to have to mess with the code for the RCPT command,
2056which sometimes uses smtp_printf() and sometimes smtp_respond(). */
2057
2058if (rcpt_in_progress)
2059 {
2060 if (rcpt_smtp_response == NULL)
2061 rcpt_smtp_response = string_copy(msg);
2062 else if (rcpt_smtp_response_same &&
2063 Ustrcmp(rcpt_smtp_response, msg) != 0)
2064 rcpt_smtp_response_same = FALSE;
2065 rcpt_in_progress = FALSE;
2066 }
2067
2068/* Not output the message, splitting it up into multiple lines if necessary. */
2069
059ec3d9
PH
2070for (;;)
2071 {
2072 uschar *nl = Ustrchr(msg, '\n');
2073 if (nl == NULL)
2074 {
a5bd321b 2075 smtp_printf("%.3s%c%.*s%s\r\n", code, final? ' ':'-', esclen, esc, msg);
059ec3d9
PH
2076 return;
2077 }
2078 else if (nl[1] == 0 || no_multiline_responses)
2079 {
a5bd321b
PH
2080 smtp_printf("%.3s%c%.*s%.*s\r\n", code, final? ' ':'-', esclen, esc,
2081 (int)(nl - msg), msg);
059ec3d9
PH
2082 return;
2083 }
2084 else
2085 {
a5bd321b 2086 smtp_printf("%.3s-%.*s%.*s\r\n", code, esclen, esc, (int)(nl - msg), msg);
059ec3d9
PH
2087 msg = nl + 1;
2088 while (isspace(*msg)) msg++;
2089 }
2090 }
2091}
2092
2093
2094
2095
2096/*************************************************
4e88a19f
PH
2097* Parse user SMTP message *
2098*************************************************/
2099
2100/* This function allows for user messages overriding the response code details
2101by providing a suitable response code string at the start of the message
2102user_msg. Check the message for starting with a response code and optionally an
2103extended status code. If found, check that the first digit is valid, and if so,
2104change the code pointer and length to use the replacement. An invalid code
2105causes a panic log; in this case, if the log messages is the same as the user
2106message, we must also adjust the value of the log message to show the code that
2107is actually going to be used (the original one).
2108
2109This function is global because it is called from receive.c as well as within
2110this module.
2111
d6a96edc
PH
2112Note that the code length returned includes the terminating whitespace
2113character, which is always included in the regex match.
2114
4e88a19f
PH
2115Arguments:
2116 code SMTP code, may involve extended status codes
d6a96edc 2117 codelen length of smtp code; if > 4 there's an ESC
4e88a19f
PH
2118 msg message text
2119 log_msg optional log message, to be adjusted with the new SMTP code
2120
2121Returns: nothing
2122*/
2123
2124void
2125smtp_message_code(uschar **code, int *codelen, uschar **msg, uschar **log_msg)
2126{
2127int n;
2128int ovector[3];
2129
2130if (msg == NULL || *msg == NULL) return;
2131
2132n = pcre_exec(regex_smtp_code, NULL, CS *msg, Ustrlen(*msg), 0,
2133 PCRE_EOPT, ovector, sizeof(ovector)/sizeof(int));
2134if (n < 0) return;
2135
2136if ((*msg)[0] != (*code)[0])
2137 {
2138 log_write(0, LOG_MAIN|LOG_PANIC, "configured error code starts with "
2139 "incorrect digit (expected %c) in \"%s\"", (*code)[0], *msg);
2140 if (log_msg != NULL && *log_msg == *msg)
2141 *log_msg = string_sprintf("%s %s", *code, *log_msg + ovector[1]);
2142 }
2143else
2144 {
2145 *code = *msg;
2146 *codelen = ovector[1]; /* Includes final space */
2147 }
2148*msg += ovector[1]; /* Chop the code off the message */
2149return;
2150}
2151
2152
2153
2154
2155/*************************************************
059ec3d9
PH
2156* Handle an ACL failure *
2157*************************************************/
2158
2159/* This function is called when acl_check() fails. As well as calls from within
2160this module, it is called from receive.c for an ACL after DATA. It sorts out
2161logging the incident, and sets up the error response. A message containing
2162newlines is turned into a multiline SMTP response, but for logging, only the
2163first line is used.
2164
a5bd321b
PH
2165There's a table of default permanent failure response codes to use in
2166globals.c, along with the table of names. VFRY is special. Despite RFC1123 it
2167defaults disabled in Exim. However, discussion in connection with RFC 821bis
2168(aka RFC 2821) has concluded that the response should be 252 in the disabled
2169state, because there are broken clients that try VRFY before RCPT. A 5xx
2170response should be given only when the address is positively known to be
2171undeliverable. Sigh. Also, for ETRN, 458 is given on refusal, and for AUTH,
2172503.
2173
2174From Exim 4.63, it is possible to override the response code details by
2175providing a suitable response code string at the start of the message provided
2176in user_msg. The code's first digit is checked for validity.
059ec3d9
PH
2177
2178Arguments:
2179 where where the ACL was called from
2180 rc the failure code
2181 user_msg a message that can be included in an SMTP response
2182 log_msg a message for logging
2183
2184Returns: 0 in most cases
2185 2 if the failure code was FAIL_DROP, in which case the
2186 SMTP connection should be dropped (this value fits with the
2187 "done" variable in smtp_setup_msg() below)
2188*/
2189
2190int
2191smtp_handle_acl_fail(int where, int rc, uschar *user_msg, uschar *log_msg)
2192{
059ec3d9 2193BOOL drop = rc == FAIL_DROP;
a5bd321b 2194int codelen = 3;
a5bd321b 2195uschar *smtp_code;
059ec3d9
PH
2196uschar *lognl;
2197uschar *sender_info = US"";
64ffc24f 2198uschar *what =
8523533c 2199#ifdef WITH_CONTENT_SCAN
64ffc24f 2200 (where == ACL_WHERE_MIME)? US"during MIME ACL checks" :
8e669ac1 2201#endif
64ffc24f
PH
2202 (where == ACL_WHERE_PREDATA)? US"DATA" :
2203 (where == ACL_WHERE_DATA)? US"after DATA" :
ca86f471 2204 (smtp_cmd_data == NULL)?
64ffc24f 2205 string_sprintf("%s in \"connect\" ACL", acl_wherenames[where]) :
ca86f471 2206 string_sprintf("%s %s", acl_wherenames[where], smtp_cmd_data);
059ec3d9
PH
2207
2208if (drop) rc = FAIL;
2209
4e88a19f 2210/* Set the default SMTP code, and allow a user message to change it. */
a5bd321b
PH
2211
2212smtp_code = (rc != FAIL)? US"451" : acl_wherecodes[where];
4e88a19f 2213smtp_message_code(&smtp_code, &codelen, &user_msg, &log_msg);
a5bd321b 2214
059ec3d9
PH
2215/* We used to have sender_address here; however, there was a bug that was not
2216updating sender_address after a rewrite during a verify. When this bug was
2217fixed, sender_address at this point became the rewritten address. I'm not sure
2218this is what should be logged, so I've changed to logging the unrewritten
2219address to retain backward compatibility. */
2220
8523533c 2221#ifndef WITH_CONTENT_SCAN
059ec3d9 2222if (where == ACL_WHERE_RCPT || where == ACL_WHERE_DATA)
8523533c
TK
2223#else
2224if (where == ACL_WHERE_RCPT || where == ACL_WHERE_DATA || where == ACL_WHERE_MIME)
2225#endif
059ec3d9 2226 {
b98bb9ac
PP
2227 sender_info = string_sprintf("F=<%s>%s%s%s%s ",
2228 sender_address_unrewritten ? sender_address_unrewritten : sender_address,
2229 sender_host_authenticated ? US" A=" : US"",
2230 sender_host_authenticated ? sender_host_authenticated : US"",
2231 sender_host_authenticated && authenticated_id ? US":" : US"",
2232 sender_host_authenticated && authenticated_id ? authenticated_id : US""
2233 );
059ec3d9
PH
2234 }
2235
2236/* If there's been a sender verification failure with a specific message, and
2237we have not sent a response about it yet, do so now, as a preliminary line for
278c6e6c
PH
2238failures, but not defers. However, always log it for defer, and log it for fail
2239unless the sender_verify_fail log selector has been turned off. */
059ec3d9
PH
2240
2241if (sender_verified_failed != NULL &&
2242 !testflag(sender_verified_failed, af_sverify_told))
2243 {
2679d413
PH
2244 BOOL save_rcpt_in_progress = rcpt_in_progress;
2245 rcpt_in_progress = FALSE; /* So as not to treat these as the error */
2246
059ec3d9
PH
2247 setflag(sender_verified_failed, af_sverify_told);
2248
278c6e6c
PH
2249 if (rc != FAIL || (log_extra_selector & LX_sender_verify_fail) != 0)
2250 log_write(0, LOG_MAIN|LOG_REJECT, "%s sender verify %s for <%s>%s",
2251 host_and_ident(TRUE),
2252 ((sender_verified_failed->special_action & 255) == DEFER)? "defer":"fail",
2253 sender_verified_failed->address,
2254 (sender_verified_failed->message == NULL)? US"" :
2255 string_sprintf(": %s", sender_verified_failed->message));
059ec3d9
PH
2256
2257 if (rc == FAIL && sender_verified_failed->user_message != NULL)
a5bd321b 2258 smtp_respond(smtp_code, codelen, FALSE, string_sprintf(
059ec3d9
PH
2259 testflag(sender_verified_failed, af_verify_pmfail)?
2260 "Postmaster verification failed while checking <%s>\n%s\n"
2261 "Several RFCs state that you are required to have a postmaster\n"
2262 "mailbox for each mail domain. This host does not accept mail\n"
2263 "from domains whose servers reject the postmaster address."
2264 :
2265 testflag(sender_verified_failed, af_verify_nsfail)?
2266 "Callback setup failed while verifying <%s>\n%s\n"
2267 "The initial connection, or a HELO or MAIL FROM:<> command was\n"
2268 "rejected. Refusing MAIL FROM:<> does not help fight spam, disregards\n"
2269 "RFC requirements, and stops you from receiving standard bounce\n"
2270 "messages. This host does not accept mail from domains whose servers\n"
2271 "refuse bounces."
2272 :
2273 "Verification failed for <%s>\n%s",
2274 sender_verified_failed->address,
2275 sender_verified_failed->user_message));
2679d413
PH
2276
2277 rcpt_in_progress = save_rcpt_in_progress;
059ec3d9
PH
2278 }
2279
2280/* Sort out text for logging */
2281
2282log_msg = (log_msg == NULL)? US"" : string_sprintf(": %s", log_msg);
2283lognl = Ustrchr(log_msg, '\n');
2284if (lognl != NULL) *lognl = 0;
2285
2286/* Send permanent failure response to the command, but the code used isn't
2287always a 5xx one - see comments at the start of this function. If the original
2288rc was FAIL_DROP we drop the connection and yield 2. */
2289
a5bd321b 2290if (rc == FAIL) smtp_respond(smtp_code, codelen, TRUE, (user_msg == NULL)?
059ec3d9
PH
2291 US"Administrative prohibition" : user_msg);
2292
2293/* Send temporary failure response to the command. Don't give any details,
2294unless acl_temp_details is set. This is TRUE for a callout defer, a "defer"
2295verb, and for a header verify when smtp_return_error_details is set.
2296
2297This conditional logic is all somewhat of a mess because of the odd
2298interactions between temp_details and return_error_details. One day it should
2299be re-implemented in a tidier fashion. */
2300
2301else
2302 {
2303 if (acl_temp_details && user_msg != NULL)
2304 {
2305 if (smtp_return_error_details &&
2306 sender_verified_failed != NULL &&
2307 sender_verified_failed->message != NULL)
2308 {
a5bd321b 2309 smtp_respond(smtp_code, codelen, FALSE, sender_verified_failed->message);
059ec3d9 2310 }
a5bd321b 2311 smtp_respond(smtp_code, codelen, TRUE, user_msg);
059ec3d9
PH
2312 }
2313 else
a5bd321b
PH
2314 smtp_respond(smtp_code, codelen, TRUE,
2315 US"Temporary local problem - please try later");
059ec3d9
PH
2316 }
2317
6ea85e9a
PH
2318/* Log the incident to the logs that are specified by log_reject_target
2319(default main, reject). This can be empty to suppress logging of rejections. If
2320the connection is not forcibly to be dropped, return 0. Otherwise, log why it
2321is closing if required and return 2. */
059ec3d9 2322
6ea85e9a
PH
2323if (log_reject_target != 0)
2324 log_write(0, log_reject_target, "%s %s%srejected %s%s",
2325 host_and_ident(TRUE),
2326 sender_info, (rc == FAIL)? US"" : US"temporarily ", what, log_msg);
059ec3d9
PH
2327
2328if (!drop) return 0;
2329
2330log_write(L_smtp_connection, LOG_MAIN, "%s closed by DROP in ACL",
2331 smtp_get_connection_info());
8f128379
PH
2332
2333/* Run the not-quit ACL, but without any custom messages. This should not be a
2334problem, because we get here only if some other ACL has issued "drop", and
2335in that case, *its* custom messages will have been used above. */
2336
2337smtp_notquit_exit(US"acl-drop", NULL, NULL);
059ec3d9
PH
2338return 2;
2339}
2340
2341
2342
2343
2344/*************************************************
8f128379
PH
2345* Handle SMTP exit when QUIT is not given *
2346*************************************************/
2347
2348/* This function provides a logging/statistics hook for when an SMTP connection
2349is dropped on the floor or the other end goes away. It's a global function
2350because it's called from receive.c as well as this module. As well as running
2351the NOTQUIT ACL, if there is one, this function also outputs a final SMTP
2352response, either with a custom message from the ACL, or using a default. There
2353is one case, however, when no message is output - after "drop". In that case,
2354the ACL that obeyed "drop" has already supplied the custom message, and NULL is
2355passed to this function.
2356
2357In case things go wrong while processing this function, causing an error that
2358may re-enter this funtion, there is a recursion check.
2359
2360Arguments:
2361 reason What $smtp_notquit_reason will be set to in the ACL;
2362 if NULL, the ACL is not run
2363 code The error code to return as part of the response
2364 defaultrespond The default message if there's no user_msg
2365
2366Returns: Nothing
2367*/
2368
2369void
2370smtp_notquit_exit(uschar *reason, uschar *code, uschar *defaultrespond, ...)
2371{
2372int rc;
2373uschar *user_msg = NULL;
2374uschar *log_msg = NULL;
2375
2376/* Check for recursive acll */
2377
2378if (smtp_exit_function_called)
2379 {
2380 log_write(0, LOG_PANIC, "smtp_notquit_exit() called more than once (%s)",
2381 reason);
2382 return;
2383 }
2384smtp_exit_function_called = TRUE;
2385
2386/* Call the not-QUIT ACL, if there is one, unless no reason is given. */
2387
2388if (acl_smtp_notquit != NULL && reason != NULL)
2389 {
2390 smtp_notquit_reason = reason;
2391 rc = acl_check(ACL_WHERE_NOTQUIT, NULL, acl_smtp_notquit, &user_msg,
2392 &log_msg);
2393 if (rc == ERROR)
2394 log_write(0, LOG_MAIN|LOG_PANIC, "ACL for not-QUIT returned ERROR: %s",
2395 log_msg);
2396 }
2397
2398/* Write an SMTP response if we are expected to give one. As the default
2399responses are all internal, they should always fit in the buffer, but code a
2400warning, just in case. Note that string_vformat() still leaves a complete
2401string, even if it is incomplete. */
2402
2403if (code != NULL && defaultrespond != NULL)
2404 {
2405 if (user_msg == NULL)
2406 {
2407 uschar buffer[128];
2408 va_list ap;
2409 va_start(ap, defaultrespond);
2410 if (!string_vformat(buffer, sizeof(buffer), CS defaultrespond, ap))
2411 log_write(0, LOG_MAIN|LOG_PANIC, "string too large in smtp_notquit_exit()");
2412 smtp_printf("%s %s\r\n", code, buffer);
2413 va_end(ap);
2414 }
2415 else
2416 smtp_respond(code, 3, TRUE, user_msg);
2417 mac_smtp_fflush();
2418 }
2419}
2420
2421
2422
2423
2424/*************************************************
d7b47fd0
PH
2425* Verify HELO argument *
2426*************************************************/
2427
2428/* This function is called if helo_verify_hosts or helo_try_verify_hosts is
2429matched. It is also called from ACL processing if verify = helo is used and
2430verification was not previously tried (i.e. helo_try_verify_hosts was not
2431matched). The result of its processing is to set helo_verified and
2432helo_verify_failed. These variables should both be FALSE for this function to
2433be called.
2434
2435Note that EHLO/HELO is legitimately allowed to quote an address literal. Allow
2436for IPv6 ::ffff: literals.
2437
2438Argument: none
2439Returns: TRUE if testing was completed;
2440 FALSE on a temporary failure
2441*/
2442
2443BOOL
2444smtp_verify_helo(void)
2445{
2446BOOL yield = TRUE;
2447
2448HDEBUG(D_receive) debug_printf("verifying EHLO/HELO argument \"%s\"\n",
2449 sender_helo_name);
2450
2451if (sender_helo_name == NULL)
2452 {
2453 HDEBUG(D_receive) debug_printf("no EHLO/HELO command was issued\n");
2454 }
2455
d1d5595c
PH
2456/* Deal with the case of -bs without an IP address */
2457
2458else if (sender_host_address == NULL)
2459 {
2460 HDEBUG(D_receive) debug_printf("no client IP address: assume success\n");
2461 helo_verified = TRUE;
2462 }
2463
2464/* Deal with the more common case when there is a sending IP address */
2465
d7b47fd0
PH
2466else if (sender_helo_name[0] == '[')
2467 {
2468 helo_verified = Ustrncmp(sender_helo_name+1, sender_host_address,
2469 Ustrlen(sender_host_address)) == 0;
2470
2471 #if HAVE_IPV6
2472 if (!helo_verified)
2473 {
2474 if (strncmpic(sender_host_address, US"::ffff:", 7) == 0)
2475 helo_verified = Ustrncmp(sender_helo_name + 1,
2476 sender_host_address + 7, Ustrlen(sender_host_address) - 7) == 0;
2477 }
2478 #endif
2479
2480 HDEBUG(D_receive)
2481 { if (helo_verified) debug_printf("matched host address\n"); }
2482 }
2483
2484/* Do a reverse lookup if one hasn't already given a positive or negative
2485response. If that fails, or the name doesn't match, try checking with a forward
2486lookup. */
2487
2488else
2489 {
2490 if (sender_host_name == NULL && !host_lookup_failed)
2491 yield = host_name_lookup() != DEFER;
2492
2493 /* If a host name is known, check it and all its aliases. */
2494
2495 if (sender_host_name != NULL)
2496 {
2497 helo_verified = strcmpic(sender_host_name, sender_helo_name) == 0;
2498
2499 if (helo_verified)
2500 {
2501 HDEBUG(D_receive) debug_printf("matched host name\n");
2502 }
2503 else
2504 {
2505 uschar **aliases = sender_host_aliases;
2506 while (*aliases != NULL)
2507 {
2508 helo_verified = strcmpic(*aliases++, sender_helo_name) == 0;
2509 if (helo_verified) break;
2510 }
2511 HDEBUG(D_receive)
2512 {
2513 if (helo_verified)
2514 debug_printf("matched alias %s\n", *(--aliases));
2515 }
2516 }
2517 }
2518
2519 /* Final attempt: try a forward lookup of the helo name */
2520
2521 if (!helo_verified)
2522 {
2523 int rc;
2524 host_item h;
2525 h.name = sender_helo_name;
2526 h.address = NULL;
2527 h.mx = MX_NONE;
2528 h.next = NULL;
2529 HDEBUG(D_receive) debug_printf("getting IP address for %s\n",
2530 sender_helo_name);
322050c2 2531 rc = host_find_byname(&h, NULL, 0, NULL, TRUE);
d7b47fd0
PH
2532 if (rc == HOST_FOUND || rc == HOST_FOUND_LOCAL)
2533 {
2534 host_item *hh = &h;
2535 while (hh != NULL)
2536 {
2537 if (Ustrcmp(hh->address, sender_host_address) == 0)
2538 {
2539 helo_verified = TRUE;
2540 HDEBUG(D_receive)
2541 debug_printf("IP address for %s matches calling address\n",
2542 sender_helo_name);
2543 break;
2544 }
2545 hh = hh->next;
2546 }
2547 }
2548 }
2549 }
2550
d1d5595c 2551if (!helo_verified) helo_verify_failed = TRUE; /* We've tried ... */
d7b47fd0
PH
2552return yield;
2553}
2554
2555
2556
2557
2558/*************************************************
4e88a19f
PH
2559* Send user response message *
2560*************************************************/
2561
2562/* This function is passed a default response code and a user message. It calls
2563smtp_message_code() to check and possibly modify the response code, and then
2564calls smtp_respond() to transmit the response. I put this into a function
2565just to avoid a lot of repetition.
2566
2567Arguments:
2568 code the response code
2569 user_msg the user message
2570
2571Returns: nothing
2572*/
2573
2574static void
2575smtp_user_msg(uschar *code, uschar *user_msg)
2576{
2577int len = 3;
2578smtp_message_code(&code, &len, &user_msg, NULL);
2579smtp_respond(code, len, TRUE, user_msg);
2580}
2581
2582
2583
2584
2585/*************************************************
059ec3d9
PH
2586* Initialize for SMTP incoming message *
2587*************************************************/
2588
2589/* This function conducts the initial dialogue at the start of an incoming SMTP
2590message, and builds a list of recipients. However, if the incoming message
2591is part of a batch (-bS option) a separate function is called since it would
2592be messy having tests splattered about all over this function. This function
2593therefore handles the case where interaction is occurring. The input and output
2594files are set up in smtp_in and smtp_out.
2595
2596The global recipients_list is set to point to a vector of recipient_item
2597blocks, whose number is given by recipients_count. This is extended by the
2598receive_add_recipient() function. The global variable sender_address is set to
2599the sender's address. The yield is +1 if a message has been successfully
2600started, 0 if a QUIT command was encountered or the connection was refused from
2601the particular host, or -1 if the connection was lost.
2602
2603Argument: none
2604
2605Returns: > 0 message successfully started (reached DATA)
2606 = 0 QUIT read or end of file reached or call refused
2607 < 0 lost connection
2608*/
2609
2610int
2611smtp_setup_msg(void)
2612{
2613int done = 0;
2614BOOL toomany = FALSE;
2615BOOL discarded = FALSE;
2616BOOL last_was_rej_mail = FALSE;
2617BOOL last_was_rcpt = FALSE;
2618void *reset_point = store_get(0);
2619
2620DEBUG(D_receive) debug_printf("smtp_setup_msg entered\n");
2621
2622/* Reset for start of new message. We allow one RSET not to be counted as a
2623nonmail command, for those MTAs that insist on sending it between every
2624message. Ditto for EHLO/HELO and for STARTTLS, to allow for going in and out of
2625TLS between messages (an Exim client may do this if it has messages queued up
2626for the host). Note: we do NOT reset AUTH at this point. */
2627
2628smtp_reset(reset_point);
2629message_ended = END_NOTSTARTED;
2630
2631cmd_list[CMD_LIST_RSET].is_mail_cmd = TRUE;
2632cmd_list[CMD_LIST_HELO].is_mail_cmd = TRUE;
2633cmd_list[CMD_LIST_EHLO].is_mail_cmd = TRUE;
2634#ifdef SUPPORT_TLS
2635cmd_list[CMD_LIST_STARTTLS].is_mail_cmd = TRUE;
2636#endif
2637
2638/* Set the local signal handler for SIGTERM - it tries to end off tidily */
2639
2640os_non_restarting_signal(SIGTERM, command_sigterm_handler);
2641
2642/* Batched SMTP is handled in a different function. */
2643
2644if (smtp_batched_input) return smtp_setup_batch_msg();
2645
2646/* Deal with SMTP commands. This loop is exited by setting done to a POSITIVE
2647value. The values are 2 larger than the required yield of the function. */
2648
2649while (done <= 0)
2650 {
2651 uschar **argv;
2652 uschar *etrn_command;
2653 uschar *etrn_serialize_key;
2654 uschar *errmess;
4e88a19f
PH
2655 uschar *log_msg, *smtp_code;
2656 uschar *user_msg = NULL;
059ec3d9
PH
2657 uschar *recipient = NULL;
2658 uschar *hello = NULL;
2659 uschar *set_id = NULL;
2660 uschar *s, *ss;
2661 BOOL was_rej_mail = FALSE;
2662 BOOL was_rcpt = FALSE;
2663 void (*oldsignal)(int);
2664 pid_t pid;
2665 int start, end, sender_domain, recipient_domain;
2666 int ptr, size, rc;
f78eb7c6 2667 int c, i;
059ec3d9
PH
2668 auth_instance *au;
2669
2670 switch(smtp_read_command(TRUE))
2671 {
2672 /* The AUTH command is not permitted to occur inside a transaction, and may
c46782ef
PH
2673 occur successfully only once per connection. Actually, that isn't quite
2674 true. When TLS is started, all previous information about a connection must
2675 be discarded, so a new AUTH is permitted at that time.
2676
2677 AUTH may only be used when it has been advertised. However, it seems that
2678 there are clients that send AUTH when it hasn't been advertised, some of
2679 them even doing this after HELO. And there are MTAs that accept this. Sigh.
2680 So there's a get-out that allows this to happen.
059ec3d9
PH
2681
2682 AUTH is initially labelled as a "nonmail command" so that one occurrence
2683 doesn't get counted. We change the label here so that multiple failing
2684 AUTHS will eventually hit the nonmail threshold. */
2685
2686 case AUTH_CMD:
b4ed4da0 2687 HAD(SCH_AUTH);
059ec3d9
PH
2688 authentication_failed = TRUE;
2689 cmd_list[CMD_LIST_AUTH].is_mail_cmd = FALSE;
2690
c46782ef 2691 if (!auth_advertised && !allow_auth_unadvertised)
059ec3d9
PH
2692 {
2693 done = synprot_error(L_smtp_protocol_error, 503, NULL,
2694 US"AUTH command used when not advertised");
2695 break;
2696 }
2697 if (sender_host_authenticated != NULL)
2698 {
2699 done = synprot_error(L_smtp_protocol_error, 503, NULL,
2700 US"already authenticated");
2701 break;
2702 }
2703 if (sender_address != NULL)
2704 {
2705 done = synprot_error(L_smtp_protocol_error, 503, NULL,
2706 US"not permitted in mail transaction");
2707 break;
2708 }
2709
2710 /* Check the ACL */
2711
2712 if (acl_smtp_auth != NULL)
2713 {
64ffc24f 2714 rc = acl_check(ACL_WHERE_AUTH, NULL, acl_smtp_auth, &user_msg, &log_msg);
059ec3d9
PH
2715 if (rc != OK)
2716 {
2717 done = smtp_handle_acl_fail(ACL_WHERE_AUTH, rc, user_msg, log_msg);
2718 break;
2719 }
2720 }
2721
2722 /* Find the name of the requested authentication mechanism. */
2723
ca86f471
PH
2724 s = smtp_cmd_data;
2725 while ((c = *smtp_cmd_data) != 0 && !isspace(c))
059ec3d9
PH
2726 {
2727 if (!isalnum(c) && c != '-' && c != '_')
2728 {
2729 done = synprot_error(L_smtp_syntax_error, 501, NULL,
2730 US"invalid character in authentication mechanism name");
2731 goto COMMAND_LOOP;
2732 }
ca86f471 2733 smtp_cmd_data++;
059ec3d9
PH
2734 }
2735
2736 /* If not at the end of the line, we must be at white space. Terminate the
2737 name and move the pointer on to any data that may be present. */
2738
ca86f471 2739 if (*smtp_cmd_data != 0)
059ec3d9 2740 {
ca86f471
PH
2741 *smtp_cmd_data++ = 0;
2742 while (isspace(*smtp_cmd_data)) smtp_cmd_data++;
059ec3d9
PH
2743 }
2744
2745 /* Search for an authentication mechanism which is configured for use
c46782ef
PH
2746 as a server and which has been advertised (unless, sigh, allow_auth_
2747 unadvertised is set). */
059ec3d9
PH
2748
2749 for (au = auths; au != NULL; au = au->next)
2750 {
2751 if (strcmpic(s, au->public_name) == 0 && au->server &&
c46782ef 2752 (au->advertised || allow_auth_unadvertised)) break;
059ec3d9
PH
2753 }
2754
2755 if (au == NULL)
2756 {
2757 done = synprot_error(L_smtp_protocol_error, 504, NULL,
2758 string_sprintf("%s authentication mechanism not supported", s));
2759 break;
2760 }
2761
f78eb7c6
PH
2762 /* Run the checking code, passing the remainder of the command line as
2763 data. Initials the $auth<n> variables as empty. Initialize $0 empty and set
2764 it as the only set numerical variable. The authenticator may set $auth<n>
2765 and also set other numeric variables. The $auth<n> variables are preferred
2766 nowadays; the numerical variables remain for backwards compatibility.
059ec3d9 2767
f78eb7c6
PH
2768 Afterwards, have a go at expanding the set_id string, even if
2769 authentication failed - for bad passwords it can be useful to log the
2770 userid. On success, require set_id to expand and exist, and put it in
2771 authenticated_id. Save this in permanent store, as the working store gets
2772 reset at HELO, RSET, etc. */
2773
2774 for (i = 0; i < AUTH_VARS; i++) auth_vars[i] = NULL;
059ec3d9
PH
2775 expand_nmax = 0;
2776 expand_nlength[0] = 0; /* $0 contains nothing */
2777
ca86f471 2778 c = (au->info->servercode)(au, smtp_cmd_data);
059ec3d9
PH
2779 if (au->set_id != NULL) set_id = expand_string(au->set_id);
2780 expand_nmax = -1; /* Reset numeric variables */
f78eb7c6 2781 for (i = 0; i < AUTH_VARS; i++) auth_vars[i] = NULL; /* Reset $auth<n> */
059ec3d9 2782
0612b098
PH
2783 /* The value of authenticated_id is stored in the spool file and printed in
2784 log lines. It must not contain binary zeros or newline characters. In
2785 normal use, it never will, but when playing around or testing, this error
2786 can (did) happen. To guard against this, ensure that the id contains only
2787 printing characters. */
2788
2789 if (set_id != NULL) set_id = string_printing(set_id);
2790
059ec3d9
PH
2791 /* For the non-OK cases, set up additional logging data if set_id
2792 is not empty. */
2793
2794 if (c != OK)
2795 {
2796 if (set_id != NULL && *set_id != 0)
2797 set_id = string_sprintf(" (set_id=%s)", set_id);
2798 else set_id = US"";
2799 }
2800
2801 /* Switch on the result */
2802
2803 switch(c)
2804 {
2805 case OK:
2806 if (au->set_id == NULL || set_id != NULL) /* Complete success */
2807 {
2808 if (set_id != NULL) authenticated_id = string_copy_malloc(set_id);
2809 sender_host_authenticated = au->name;
2810 authentication_failed = FALSE;
2811 received_protocol =
817d9f57 2812 protocols[pextend + pauthed + ((tls_in.active >= 0)? pcrpted:0)] +
059ec3d9
PH
2813 ((sender_host_address != NULL)? pnlocal : 0);
2814 s = ss = US"235 Authentication succeeded";
2815 authenticated_by = au;
2816 break;
2817 }
2818
2819 /* Authentication succeeded, but we failed to expand the set_id string.
2820 Treat this as a temporary error. */
2821
2822 auth_defer_msg = expand_string_message;
2823 /* Fall through */
2824
2825 case DEFER:
2826 s = string_sprintf("435 Unable to authenticate at present%s",
2827 auth_defer_user_msg);
2828 ss = string_sprintf("435 Unable to authenticate at present%s: %s",
2829 set_id, auth_defer_msg);
2830 break;
2831
2832 case BAD64:
2833 s = ss = US"501 Invalid base64 data";
2834 break;
2835
2836 case CANCELLED:
2837 s = ss = US"501 Authentication cancelled";
2838 break;
2839
2840 case UNEXPECTED:
2841 s = ss = US"553 Initial data not expected";
2842 break;
2843
2844 case FAIL:
2845 s = US"535 Incorrect authentication data";
2846 ss = string_sprintf("535 Incorrect authentication data%s", set_id);
2847 break;
2848
2849 default:
2850 s = US"435 Internal error";
2851 ss = string_sprintf("435 Internal error%s: return %d from authentication "
2852 "check", set_id, c);
2853 break;
2854 }
2855
2856 smtp_printf("%s\r\n", s);
2857 if (c != OK)
2858 log_write(0, LOG_MAIN|LOG_REJECT, "%s authenticator failed for %s: %s",
2859 au->name, host_and_ident(FALSE), ss);
2860
2861 break; /* AUTH_CMD */
2862
2863 /* The HELO/EHLO commands are permitted to appear in the middle of a
2864 session as well as at the beginning. They have the effect of a reset in
2865 addition to their other functions. Their absence at the start cannot be
2866 taken to be an error.
2867
2868 RFC 2821 says:
2869
2870 If the EHLO command is not acceptable to the SMTP server, 501, 500,
2871 or 502 failure replies MUST be returned as appropriate. The SMTP
2872 server MUST stay in the same state after transmitting these replies
2873 that it was in before the EHLO was received.
2874
2875 Therefore, we do not do the reset until after checking the command for
2876 acceptability. This change was made for Exim release 4.11. Previously
2877 it did the reset first. */
2878
2879 case HELO_CMD:
b4ed4da0 2880 HAD(SCH_HELO);
059ec3d9
PH
2881 hello = US"HELO";
2882 esmtp = FALSE;
2883 goto HELO_EHLO;
2884
2885 case EHLO_CMD:
b4ed4da0 2886 HAD(SCH_EHLO);
059ec3d9
PH
2887 hello = US"EHLO";
2888 esmtp = TRUE;
2889
2890 HELO_EHLO: /* Common code for HELO and EHLO */
2891 cmd_list[CMD_LIST_HELO].is_mail_cmd = FALSE;
2892 cmd_list[CMD_LIST_EHLO].is_mail_cmd = FALSE;
2893
2894 /* Reject the HELO if its argument was invalid or non-existent. A
2895 successful check causes the argument to be saved in malloc store. */
2896
ca86f471 2897 if (!check_helo(smtp_cmd_data))
059ec3d9
PH
2898 {
2899 smtp_printf("501 Syntactically invalid %s argument(s)\r\n", hello);
2900
2901 log_write(0, LOG_MAIN|LOG_REJECT, "rejected %s from %s: syntactically "
2902 "invalid argument(s): %s", hello, host_and_ident(FALSE),
3ee512ff
PH
2903 (*smtp_cmd_argument == 0)? US"(no argument given)" :
2904 string_printing(smtp_cmd_argument));
059ec3d9
PH
2905
2906 if (++synprot_error_count > smtp_max_synprot_errors)
2907 {
2908 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
2909 "syntax or protocol errors (last command was \"%s\")",
3ee512ff 2910 host_and_ident(FALSE), smtp_cmd_buffer);
059ec3d9
PH
2911 done = 1;
2912 }
2913
2914 break;
2915 }
2916
2917 /* If sender_host_unknown is true, we have got here via the -bs interface,
2918 not called from inetd. Otherwise, we are running an IP connection and the
2919 host address will be set. If the helo name is the primary name of this
2920 host and we haven't done a reverse lookup, force one now. If helo_required
2921 is set, ensure that the HELO name matches the actual host. If helo_verify
2922 is set, do the same check, but softly. */
2923
2924 if (!sender_host_unknown)
2925 {
2926 BOOL old_helo_verified = helo_verified;
ca86f471 2927 uschar *p = smtp_cmd_data;
059ec3d9
PH
2928
2929 while (*p != 0 && !isspace(*p)) { *p = tolower(*p); p++; }
2930 *p = 0;
2931
2932 /* Force a reverse lookup if HELO quoted something in helo_lookup_domains
2933 because otherwise the log can be confusing. */
2934
2935 if (sender_host_name == NULL &&
2936 (deliver_domain = sender_helo_name, /* set $domain */
2937 match_isinlist(sender_helo_name, &helo_lookup_domains, 0,
2938 &domainlist_anchor, NULL, MCL_DOMAIN, TRUE, NULL)) == OK)
2939 (void)host_name_lookup();
2940
2941 /* Rebuild the fullhost info to include the HELO name (and the real name
2942 if it was looked up.) */
2943
2944 host_build_sender_fullhost(); /* Rebuild */
2945 set_process_info("handling%s incoming connection from %s",
817d9f57 2946 (tls_in.active >= 0)? " TLS" : "", host_and_ident(FALSE));
059ec3d9
PH
2947
2948 /* Verify if configured. This doesn't give much security, but it does
d7b47fd0
PH
2949 make some people happy to be able to do it. If helo_required is set,
2950 (host matches helo_verify_hosts) failure forces rejection. If helo_verify
2951 is set (host matches helo_try_verify_hosts), it does not. This is perhaps
2952 now obsolescent, since the verification can now be requested selectively
2953 at ACL time. */
059ec3d9 2954
d7b47fd0 2955 helo_verified = helo_verify_failed = FALSE;
059ec3d9
PH
2956 if (helo_required || helo_verify)
2957 {
d7b47fd0 2958 BOOL tempfail = !smtp_verify_helo();
059ec3d9
PH
2959 if (!helo_verified)
2960 {
2961 if (helo_required)
2962 {
2963 smtp_printf("%d %s argument does not match calling host\r\n",
2964 tempfail? 451 : 550, hello);
2965 log_write(0, LOG_MAIN|LOG_REJECT, "%srejected \"%s %s\" from %s",
2966 tempfail? "temporarily " : "",
2967 hello, sender_helo_name, host_and_ident(FALSE));
2968 helo_verified = old_helo_verified;
2969 break; /* End of HELO/EHLO processing */
2970 }
2971 HDEBUG(D_all) debug_printf("%s verification failed but host is in "
2972 "helo_try_verify_hosts\n", hello);
2973 }
2974 }
2975 }
2976
8523533c
TK
2977#ifdef EXPERIMENTAL_SPF
2978 /* set up SPF context */
2979 spf_init(sender_helo_name, sender_host_address);
2980#endif
2981
a14e5636
PH
2982 /* Apply an ACL check if one is defined; afterwards, recheck
2983 synchronization in case the client started sending in a delay. */
059ec3d9
PH
2984
2985 if (acl_smtp_helo != NULL)
2986 {
64ffc24f 2987 rc = acl_check(ACL_WHERE_HELO, NULL, acl_smtp_helo, &user_msg, &log_msg);
059ec3d9
PH
2988 if (rc != OK)
2989 {
2990 done = smtp_handle_acl_fail(ACL_WHERE_HELO, rc, user_msg, log_msg);
2991 sender_helo_name = NULL;
2992 host_build_sender_fullhost(); /* Rebuild */
2993 break;
2994 }
a14e5636 2995 else if (!check_sync()) goto SYNC_FAILURE;
059ec3d9
PH
2996 }
2997
4e88a19f
PH
2998 /* Generate an OK reply. The default string includes the ident if present,
2999 and also the IP address if present. Reflecting back the ident is intended
3000 as a deterrent to mail forgers. For maximum efficiency, and also because
3001 some broken systems expect each response to be in a single packet, arrange
3002 that the entire reply is sent in one write(). */
059ec3d9
PH
3003
3004 auth_advertised = FALSE;
3005 pipelining_advertised = FALSE;
3006 #ifdef SUPPORT_TLS
3007 tls_advertised = FALSE;
3008 #endif
3009
d6a96edc 3010 smtp_code = US"250 "; /* Default response code plus space*/
4e88a19f
PH
3011 if (user_msg == NULL)
3012 {
3013 s = string_sprintf("%.3s %s Hello %s%s%s",
3014 smtp_code,
3015 smtp_active_hostname,
3016 (sender_ident == NULL)? US"" : sender_ident,
3017 (sender_ident == NULL)? US"" : US" at ",
3018 (sender_host_name == NULL)? sender_helo_name : sender_host_name);
3019
3020 ptr = Ustrlen(s);
3021 size = ptr + 1;
059ec3d9 3022
4e88a19f
PH
3023 if (sender_host_address != NULL)
3024 {
3025 s = string_cat(s, &size, &ptr, US" [", 2);
3026 s = string_cat(s, &size, &ptr, sender_host_address,
3027 Ustrlen(sender_host_address));
3028 s = string_cat(s, &size, &ptr, US"]", 1);
3029 }
3030 }
3031
d6a96edc
PH
3032 /* A user-supplied EHLO greeting may not contain more than one line. Note
3033 that the code returned by smtp_message_code() includes the terminating
3034 whitespace character. */
059ec3d9 3035
4e88a19f 3036 else
059ec3d9 3037 {
4e88a19f 3038 char *ss;
d6a96edc 3039 int codelen = 4;
4e88a19f 3040 smtp_message_code(&smtp_code, &codelen, &user_msg, NULL);
d6a96edc 3041 s = string_sprintf("%.*s%s", codelen, smtp_code, user_msg);
4e88a19f
PH
3042 if ((ss = strpbrk(CS s, "\r\n")) != NULL)
3043 {
3044 log_write(0, LOG_MAIN|LOG_PANIC, "EHLO/HELO response must not contain "
3045 "newlines: message truncated: %s", string_printing(s));
3046 *ss = 0;
3047 }
3048 ptr = Ustrlen(s);
3049 size = ptr + 1;
059ec3d9
PH
3050 }
3051
3052 s = string_cat(s, &size, &ptr, US"\r\n", 2);
3053
3054 /* If we received EHLO, we must create a multiline response which includes
3055 the functions supported. */
3056
3057 if (esmtp)
3058 {
3059 s[3] = '-';
3060
3061 /* I'm not entirely happy with this, as an MTA is supposed to check
3062 that it has enough room to accept a message of maximum size before
3063 it sends this. However, there seems little point in not sending it.
3064 The actual size check happens later at MAIL FROM time. By postponing it
3065 till then, VRFY and EXPN can be used after EHLO when space is short. */
3066
3067 if (thismessage_size_limit > 0)
3068 {
4e88a19f
PH
3069 sprintf(CS big_buffer, "%.3s-SIZE %d\r\n", smtp_code,
3070 thismessage_size_limit);
059ec3d9
PH
3071 s = string_cat(s, &size, &ptr, big_buffer, Ustrlen(big_buffer));
3072 }
3073 else
3074 {
4e88a19f
PH
3075 s = string_cat(s, &size, &ptr, smtp_code, 3);
3076 s = string_cat(s, &size, &ptr, US"-SIZE\r\n", 7);
059ec3d9
PH
3077 }
3078
3079 /* Exim does not do protocol conversion or data conversion. It is 8-bit
3080 clean; if it has an 8-bit character in its hand, it just sends it. It
3081 cannot therefore specify 8BITMIME and remain consistent with the RFCs.
3082 However, some users want this option simply in order to stop MUAs
3083 mangling messages that contain top-bit-set characters. It is therefore
3084 provided as an option. */
3085
3086 if (accept_8bitmime)
4e88a19f
PH
3087 {
3088 s = string_cat(s, &size, &ptr, smtp_code, 3);
3089 s = string_cat(s, &size, &ptr, US"-8BITMIME\r\n", 11);
3090 }
059ec3d9
PH
3091
3092 /* Advertise ETRN if there's an ACL checking whether a host is
3093 permitted to issue it; a check is made when any host actually tries. */
3094
3095 if (acl_smtp_etrn != NULL)
3096 {
4e88a19f
PH
3097 s = string_cat(s, &size, &ptr, smtp_code, 3);
3098 s = string_cat(s, &size, &ptr, US"-ETRN\r\n", 7);
059ec3d9
PH
3099 }
3100
3101 /* Advertise EXPN if there's an ACL checking whether a host is
3102 permitted to issue it; a check is made when any host actually tries. */
3103
3104 if (acl_smtp_expn != NULL)
3105 {
4e88a19f
PH
3106 s = string_cat(s, &size, &ptr, smtp_code, 3);
3107 s = string_cat(s, &size, &ptr, US"-EXPN\r\n", 7);
059ec3d9
PH
3108 }
3109
3110 /* Exim is quite happy with pipelining, so let the other end know that
3111 it is safe to use it, unless advertising is disabled. */
3112
cf8b11a5
PH
3113 if (pipelining_enable &&
3114 verify_check_host(&pipelining_advertise_hosts) == OK)
059ec3d9 3115 {
4e88a19f
PH
3116 s = string_cat(s, &size, &ptr, smtp_code, 3);
3117 s = string_cat(s, &size, &ptr, US"-PIPELINING\r\n", 13);
059ec3d9
PH
3118 sync_cmd_limit = NON_SYNC_CMD_PIPELINING;
3119 pipelining_advertised = TRUE;
3120 }
3121
3122 /* If any server authentication mechanisms are configured, advertise
3123 them if the current host is in auth_advertise_hosts. The problem with
3124 advertising always is that some clients then require users to
3125 authenticate (and aren't configurable otherwise) even though it may not
3126 be necessary (e.g. if the host is in host_accept_relay).
3127
3128 RFC 2222 states that SASL mechanism names contain only upper case
3129 letters, so output the names in upper case, though we actually recognize
3130 them in either case in the AUTH command. */
3131
3132 if (auths != NULL)
3133 {
3134 if (verify_check_host(&auth_advertise_hosts) == OK)
3135 {
3136 auth_instance *au;
3137 BOOL first = TRUE;
3138 for (au = auths; au != NULL; au = au->next)
3139 {
3140 if (au->server && (au->advertise_condition == NULL ||
3141 expand_check_condition(au->advertise_condition, au->name,
3142 US"authenticator")))
3143 {
3144 int saveptr;
3145 if (first)
3146 {
4e88a19f
PH
3147 s = string_cat(s, &size, &ptr, smtp_code, 3);
3148 s = string_cat(s, &size, &ptr, US"-AUTH", 5);
059ec3d9
PH
3149 first = FALSE;
3150 auth_advertised = TRUE;
3151 }
3152 saveptr = ptr;
3153 s = string_cat(s, &size, &ptr, US" ", 1);
3154 s = string_cat(s, &size, &ptr, au->public_name,
3155 Ustrlen(au->public_name));
3156 while (++saveptr < ptr) s[saveptr] = toupper(s[saveptr]);
3157 au->advertised = TRUE;
3158 }
3159 else au->advertised = FALSE;
3160 }
3161 if (!first) s = string_cat(s, &size, &ptr, US"\r\n", 2);
3162 }
3163 }
3164
3165 /* Advertise TLS (Transport Level Security) aka SSL (Secure Socket Layer)
3166 if it has been included in the binary, and the host matches
3167 tls_advertise_hosts. We must *not* advertise if we are already in a
3168 secure connection. */
3169
3170 #ifdef SUPPORT_TLS
817d9f57 3171 if (tls_in.active < 0 &&
059ec3d9
PH
3172 verify_check_host(&tls_advertise_hosts) != FAIL)
3173 {
4e88a19f
PH
3174 s = string_cat(s, &size, &ptr, smtp_code, 3);
3175 s = string_cat(s, &size, &ptr, US"-STARTTLS\r\n", 11);
059ec3d9
PH
3176 tls_advertised = TRUE;
3177 }
3178 #endif
3179
3180 /* Finish off the multiline reply with one that is always available. */
3181
4e88a19f
PH
3182 s = string_cat(s, &size, &ptr, smtp_code, 3);
3183 s = string_cat(s, &size, &ptr, US" HELP\r\n", 7);
059ec3d9
PH
3184 }
3185
3186 /* Terminate the string (for debug), write it, and note that HELO/EHLO
3187 has been seen. */
3188
3189 s[ptr] = 0;
3190
3191 #ifdef SUPPORT_TLS
817d9f57 3192 if (tls_in.active >= 0) (void)tls_write(TRUE, s, ptr); else
059ec3d9
PH
3193 #endif
3194
1ac6b2e7
JH
3195 {
3196 int i = fwrite(s, 1, ptr, smtp_out); i = i; /* compiler quietening */
3197 }
898d150f
PH
3198 DEBUG(D_receive)
3199 {
3200 uschar *cr;
3201 while ((cr = Ustrchr(s, '\r')) != NULL) /* lose CRs */
3202 memmove(cr, cr + 1, (ptr--) - (cr - s));
3203 debug_printf("SMTP>> %s", s);
3204 }
059ec3d9 3205 helo_seen = TRUE;
4e88a19f
PH
3206
3207 /* Reset the protocol and the state, abandoning any previous message. */
3208
3209 received_protocol = (esmtp?
3210 protocols[pextend +
3211 ((sender_host_authenticated != NULL)? pauthed : 0) +
817d9f57 3212 ((tls_in.active >= 0)? pcrpted : 0)]
4e88a19f 3213 :
817d9f57 3214 protocols[pnormal + ((tls_in.active >= 0)? pcrpted : 0)])
4e88a19f
PH
3215 +
3216 ((sender_host_address != NULL)? pnlocal : 0);
3217
3218 smtp_reset(reset_point);
3219 toomany = FALSE;
059ec3d9
PH
3220 break; /* HELO/EHLO */
3221
3222
3223 /* The MAIL command requires an address as an operand. All we do
3224 here is to parse it for syntactic correctness. The form "<>" is
3225 a special case which converts into an empty string. The start/end
3226 pointers in the original are not used further for this address, as
3227 it is the canonical extracted address which is all that is kept. */
3228
3229 case MAIL_CMD:
b4ed4da0 3230 HAD(SCH_MAIL);
059ec3d9
PH
3231 smtp_mailcmd_count++; /* Count for limit and ratelimit */
3232 was_rej_mail = TRUE; /* Reset if accepted */
d27f98fe 3233 env_mail_type_t * mail_args; /* Sanity check & validate args */
059ec3d9
PH
3234
3235 if (helo_required && !helo_seen)
3236 {
3237 smtp_printf("503 HELO or EHLO required\r\n");
3238 log_write(0, LOG_MAIN|LOG_REJECT, "rejected MAIL from %s: no "
3239 "HELO/EHLO given", host_and_ident(FALSE));
3240 break;
3241 }
3242
3243 if (sender_address != NULL)
3244 {
3245 done = synprot_error(L_smtp_protocol_error, 503, NULL,
3246 US"sender already given");
3247 break;
3248 }
3249
ca86f471 3250 if (smtp_cmd_data[0] == 0)
059ec3d9
PH
3251 {
3252 done = synprot_error(L_smtp_protocol_error, 501, NULL,
3253 US"MAIL must have an address operand");
3254 break;
3255 }
3256
3257 /* Check to see if the limit for messages per connection would be
3258 exceeded by accepting further messages. */
3259
3260 if (smtp_accept_max_per_connection > 0 &&
3261 smtp_mailcmd_count > smtp_accept_max_per_connection)
3262 {
3263 smtp_printf("421 too many messages in this connection\r\n");
3264 log_write(0, LOG_MAIN|LOG_REJECT, "rejected MAIL command %s: too many "
3265 "messages in one connection", host_and_ident(TRUE));
3266 break;
3267 }
3268
3269 /* Reset for start of message - even if this is going to fail, we
3270 obviously need to throw away any previous data. */
3271
3272 smtp_reset(reset_point);
3273 toomany = FALSE;
3274 sender_data = recipient_data = NULL;
3275
3276 /* Loop, checking for ESMTP additions to the MAIL FROM command. */
3277
3278 if (esmtp) for(;;)
3279 {
3280 uschar *name, *value, *end;
3281 unsigned long int size;
d27f98fe 3282 BOOL arg_error = FALSE;
059ec3d9
PH
3283
3284 if (!extract_option(&name, &value)) break;
3285
d27f98fe
TL
3286 for (mail_args = env_mail_type_list;
3287 (char *)mail_args < (char *)env_mail_type_list + sizeof(env_mail_type_list);
3288 mail_args++
3289 )
059ec3d9 3290 {
d27f98fe
TL
3291 if (strcmpic(name, mail_args->name) == 0)
3292 break;
059ec3d9 3293 }
d27f98fe
TL
3294 if (mail_args->need_value && strcmpic(value, US"") == 0)
3295 break;
3296 /* This doesn't seem right to use
3297 if ((char *)mail_args >= (char *)env_mail_type_list + sizeof(env_mail_type_list))
3298 goto BAD_MAIL_ARGS;
3299 */
059ec3d9 3300
d27f98fe 3301 switch(mail_args->value)
059ec3d9 3302 {
d27f98fe
TL
3303 /* Handle SIZE= by reading the value. We don't do the check till later,
3304 in order to be able to log the sender address on failure. */
3305 case ENV_MAIL_OPT_SIZE:
3306 /* if (strcmpic(name, US"SIZE") == 0 && */
3307 if (((size = Ustrtoul(value, &end, 10)), *end == 0))
059ec3d9 3308 {
d27f98fe
TL
3309 if ((size == ULONG_MAX && errno == ERANGE) || size > INT_MAX)
3310 size = INT_MAX;
3311 message_size = (int)size;
059ec3d9
PH
3312 }
3313 else
d27f98fe
TL
3314 arg_error = TRUE;
3315 break;
059ec3d9 3316
d27f98fe
TL
3317 /* If this session was initiated with EHLO and accept_8bitmime is set,
3318 Exim will have indicated that it supports the BODY=8BITMIME option. In
3319 fact, it does not support this according to the RFCs, in that it does not
3320 take any special action for forwarding messages containing 8-bit
3321 characters. That is why accept_8bitmime is not the default setting, but
3322 some sites want the action that is provided. We recognize both "8BITMIME"
3323 and "7BIT" as body types, but take no action. */
3324 case ENV_MAIL_OPT_BODY:
3c0a92dc
JH
3325 if (accept_8bitmime) {
3326 if (strcmpic(value, US"8BITMIME") == 0) {
3327 body_8bitmime = 8;
3328 } else if (strcmpic(value, US"7BIT") == 0) {
3329 body_8bitmime = 7;
3330 } else {
3331 body_8bitmime = 0;
3332 done = synprot_error(L_smtp_syntax_error, 501, NULL,
3333 US"invalid data for BODY");
3334 goto COMMAND_LOOP;
3335 }
3336 DEBUG(D_receive) debug_printf("8BITMIME: %d\n", body_8bitmime);
3337 break;
3338 }
d27f98fe
TL
3339 arg_error = TRUE;
3340 break;
059ec3d9 3341
d27f98fe
TL
3342 /* Handle the AUTH extension. If the value given is not "<>" and either
3343 the ACL says "yes" or there is no ACL but the sending host is
3344 authenticated, we set it up as the authenticated sender. However, if the
3345 authenticator set a condition to be tested, we ignore AUTH on MAIL unless
3346 the condition is met. The value of AUTH is an xtext, which means that +,
3347 = and cntrl chars are coded in hex; however "<>" is unaffected by this
3348 coding. */
3349 case ENV_MAIL_OPT_AUTH:
3350 if (Ustrcmp(value, "<>") != 0)
3351 {
3352 int rc;
3353 uschar *ignore_msg;
059ec3d9 3354
d27f98fe
TL
3355 if (auth_xtextdecode(value, &authenticated_sender) < 0)
3356 {
3357 /* Put back terminator overrides for error message */
3358 name[-1] = ' ';
3359 value[-1] = '=';
3360 done = synprot_error(L_smtp_syntax_error, 501, NULL,
3361 US"invalid data for AUTH");
3362 goto COMMAND_LOOP;
3363 }
3364 if (acl_smtp_mailauth == NULL)
3365 {
3366 ignore_msg = US"client not authenticated";
3367 rc = (sender_host_authenticated != NULL)? OK : FAIL;
3368 }
3369 else
3370 {
3371 ignore_msg = US"rejected by ACL";
3372 rc = acl_check(ACL_WHERE_MAILAUTH, NULL, acl_smtp_mailauth,
3373 &user_msg, &log_msg);
3374 }
3375
3376 switch (rc)
3377 {
3378 case OK:
3379 if (authenticated_by == NULL ||
3380 authenticated_by->mail_auth_condition == NULL ||
3381 expand_check_condition(authenticated_by->mail_auth_condition,
3382 authenticated_by->name, US"authenticator"))
3383 break; /* Accept the AUTH */
3384
3385 ignore_msg = US"server_mail_auth_condition failed";
3386 if (authenticated_id != NULL)
3387 ignore_msg = string_sprintf("%s: authenticated ID=\"%s\"",
3388 ignore_msg, authenticated_id);
3389
3390 /* Fall through */
3391
3392 case FAIL:
3393 authenticated_sender = NULL;
3394 log_write(0, LOG_MAIN, "ignoring AUTH=%s from %s (%s)",
3395 value, host_and_ident(TRUE), ignore_msg);
3396 break;
3397
3398 /* Should only get DEFER or ERROR here. Put back terminator
3399 overrides for error message */
3400
3401 default:
3402 name[-1] = ' ';
3403 value[-1] = '=';
3404 (void)smtp_handle_acl_fail(ACL_WHERE_MAILAUTH, rc, user_msg,
3405 log_msg);
3406 goto COMMAND_LOOP;
3407 }
059ec3d9 3408 }
d27f98fe
TL
3409 break;
3410
3411 /* Unknown option. Stick back the terminator characters and break
3412 the loop. An error for a malformed address will occur. */
3413 default:
3414
3415 /* BAD_MAIL_ARGS: */
3416 name[-1] = ' ';
3417 value[-1] = '=';
3418 break;
059ec3d9 3419 }
d27f98fe
TL
3420 /* Break out of for loop if switch() had bad argument or
3421 when start of the email address is reached */
3422 if (arg_error) break;
059ec3d9
PH
3423 }
3424
3425 /* If we have passed the threshold for rate limiting, apply the current
3426 delay, and update it for next time, provided this is a limited host. */
3427
3428 if (smtp_mailcmd_count > smtp_rlm_threshold &&
3429 verify_check_host(&smtp_ratelimit_hosts) == OK)
3430 {
3431 DEBUG(D_receive) debug_printf("rate limit MAIL: delay %.3g sec\n",
3432 smtp_delay_mail/1000.0);
3433 millisleep((int)smtp_delay_mail);
3434 smtp_delay_mail *= smtp_rlm_factor;
3435 if (smtp_delay_mail > (double)smtp_rlm_limit)
3436 smtp_delay_mail = (double)smtp_rlm_limit;
3437 }
3438
3439 /* Now extract the address, first applying any SMTP-time rewriting. The
3440 TRUE flag allows "<>" as a sender address. */
3441
3442 raw_sender = ((rewrite_existflags & rewrite_smtp) != 0)?
ca86f471
PH
3443 rewrite_one(smtp_cmd_data, rewrite_smtp, NULL, FALSE, US"",
3444 global_rewrite_rules) : smtp_cmd_data;
059ec3d9
PH
3445
3446 /* rfc821_domains = TRUE; << no longer needed */
3447 raw_sender =
3448 parse_extract_address(raw_sender, &errmess, &start, &end, &sender_domain,
3449 TRUE);
3450 /* rfc821_domains = FALSE; << no longer needed */
3451
3452 if (raw_sender == NULL)
3453 {
ca86f471 3454 done = synprot_error(L_smtp_syntax_error, 501, smtp_cmd_data, errmess);
059ec3d9
PH
3455 break;
3456 }
3457
3458 sender_address = raw_sender;
3459
3460 /* If there is a configured size limit for mail, check that this message
3461 doesn't exceed it. The check is postponed to this point so that the sender
3462 can be logged. */
3463
3464 if (thismessage_size_limit > 0 && message_size > thismessage_size_limit)
3465 {
3466 smtp_printf("552 Message size exceeds maximum permitted\r\n");
3467 log_write(L_size_reject,
3468 LOG_MAIN|LOG_REJECT, "rejected MAIL FROM:<%s> %s: "
3469 "message too big: size%s=%d max=%d",
3470 sender_address,
3471 host_and_ident(TRUE),
3472 (message_size == INT_MAX)? ">" : "",
3473 message_size,
3474 thismessage_size_limit);
3475 sender_address = NULL;
3476 break;
3477 }
3478
3479 /* Check there is enough space on the disk unless configured not to.
3480 When smtp_check_spool_space is set, the check is for thismessage_size_limit
3481 plus the current message - i.e. we accept the message only if it won't
3482 reduce the space below the threshold. Add 5000 to the size to allow for
3483 overheads such as the Received: line and storing of recipients, etc.
3484 By putting the check here, even when SIZE is not given, it allow VRFY
3485 and EXPN etc. to be used when space is short. */
3486
3487 if (!receive_check_fs(
3488 (smtp_check_spool_space && message_size >= 0)?
3489 message_size + 5000 : 0))
3490 {
3491 smtp_printf("452 Space shortage, please try later\r\n");
3492 sender_address = NULL;
3493 break;
3494 }
3495
3496 /* If sender_address is unqualified, reject it, unless this is a locally
3497 generated message, or the sending host or net is permitted to send
3498 unqualified addresses - typically local machines behaving as MUAs -
3499 in which case just qualify the address. The flag is set above at the start
3500 of the SMTP connection. */
3501
3502 if (sender_domain == 0 && sender_address[0] != 0)
3503 {
3504 if (allow_unqualified_sender)
3505 {
3506 sender_domain = Ustrlen(sender_address) + 1;
3507 sender_address = rewrite_address_qualify(sender_address, FALSE);
3508 DEBUG(D_receive) debug_printf("unqualified address %s accepted\n",
3509 raw_sender);
3510 }
3511 else
3512 {
3513 smtp_printf("501 %s: sender address must contain a domain\r\n",
ca86f471 3514 smtp_cmd_data);
059ec3d9
PH
3515 log_write(L_smtp_syntax_error,
3516 LOG_MAIN|LOG_REJECT,
3517 "unqualified sender rejected: <%s> %s%s",
3518 raw_sender,
3519 host_and_ident(TRUE),
3520 host_lookup_msg);
3521 sender_address = NULL;
3522 break;
3523 }
3524 }
3525
a14e5636
PH
3526 /* Apply an ACL check if one is defined, before responding. Afterwards,
3527 when pipelining is not advertised, do another sync check in case the ACL
3528 delayed and the client started sending in the meantime. */
059ec3d9 3529
a14e5636
PH
3530 if (acl_smtp_mail == NULL) rc = OK; else
3531 {
3532 rc = acl_check(ACL_WHERE_MAIL, NULL, acl_smtp_mail, &user_msg, &log_msg);
3533 if (rc == OK && !pipelining_advertised && !check_sync())
3534 goto SYNC_FAILURE;
3535 }
059ec3d9
PH
3536
3537 if (rc == OK || rc == DISCARD)
3538 {
4e88a19f
PH
3539 if (user_msg == NULL) smtp_printf("250 OK\r\n");
3540 else smtp_user_msg(US"250", user_msg);
059ec3d9
PH
3541 smtp_delay_rcpt = smtp_rlr_base;
3542 recipients_discarded = (rc == DISCARD);
3543 was_rej_mail = FALSE;
3544 }
059ec3d9
PH
3545 else
3546 {
3547 done = smtp_handle_acl_fail(ACL_WHERE_MAIL, rc, user_msg, log_msg);
3548 sender_address = NULL;
3549 }
3550 break;
3551
3552
2679d413
PH
3553 /* The RCPT command requires an address as an operand. There may be any
3554 number of RCPT commands, specifying multiple recipients. We build them all
3555 into a data structure. The start/end values given by parse_extract_address
3556 are not used, as we keep only the extracted address. */
059ec3d9
PH
3557
3558 case RCPT_CMD:
b4ed4da0 3559 HAD(SCH_RCPT);
059ec3d9 3560 rcpt_count++;
2679d413 3561 was_rcpt = rcpt_in_progress = TRUE;
059ec3d9
PH
3562
3563 /* There must be a sender address; if the sender was rejected and
3564 pipelining was advertised, we assume the client was pipelining, and do not
3565 count this as a protocol error. Reset was_rej_mail so that further RCPTs
3566 get the same treatment. */
3567
3568 if (sender_address == NULL)
3569 {
3570 if (pipelining_advertised && last_was_rej_mail)
3571 {
3572 smtp_printf("503 sender not yet given\r\n");
3573 was_rej_mail = TRUE;
3574 }
3575 else
3576 {
3577 done = synprot_error(L_smtp_protocol_error, 503, NULL,
3578 US"sender not yet given");
3579 was_rcpt = FALSE; /* Not a valid RCPT */
3580 }
3581 rcpt_fail_count++;
3582 break;
3583 }
3584
3585 /* Check for an operand */
3586
ca86f471 3587 if (smtp_cmd_data[0] == 0)
059ec3d9
PH
3588 {
3589 done = synprot_error(L_smtp_syntax_error, 501, NULL,
3590 US"RCPT must have an address operand");
3591 rcpt_fail_count++;
3592 break;
3593 }
3594
3595 /* Apply SMTP rewriting then extract the working address. Don't allow "<>"
3596 as a recipient address */
3597
3598 recipient = ((rewrite_existflags & rewrite_smtp) != 0)?
ca86f471
PH
3599 rewrite_one(smtp_cmd_data, rewrite_smtp, NULL, FALSE, US"",
3600 global_rewrite_rules) : smtp_cmd_data;
059ec3d9
PH
3601
3602 /* rfc821_domains = TRUE; << no longer needed */
3603 recipient = parse_extract_address(recipient, &errmess, &start, &end,
3604 &recipient_domain, FALSE);
3605 /* rfc821_domains = FALSE; << no longer needed */
3606
3607 if (recipient == NULL)
3608 {
ca86f471 3609 done = synprot_error(L_smtp_syntax_error, 501, smtp_cmd_data, errmess);
059ec3d9
PH
3610 rcpt_fail_count++;
3611 break;
3612 }
3613
3614 /* If the recipient address is unqualified, reject it, unless this is a
3615 locally generated message. However, unqualified addresses are permitted
3616 from a configured list of hosts and nets - typically when behaving as
3617 MUAs rather than MTAs. Sad that SMTP is used for both types of traffic,
3618 really. The flag is set at the start of the SMTP connection.
3619
3620 RFC 1123 talks about supporting "the reserved mailbox postmaster"; I always
3621 assumed this meant "reserved local part", but the revision of RFC 821 and
3622 friends now makes it absolutely clear that it means *mailbox*. Consequently
3623 we must always qualify this address, regardless. */
3624
3625 if (recipient_domain == 0)
3626 {
3627 if (allow_unqualified_recipient ||
3628 strcmpic(recipient, US"postmaster") == 0)
3629 {
3630 DEBUG(D_receive) debug_printf("unqualified address %s accepted\n",
3631 recipient);
3632 recipient_domain = Ustrlen(recipient) + 1;
3633 recipient = rewrite_address_qualify(recipient, TRUE);
3634 }
3635 else
3636 {
3637 rcpt_fail_count++;
3638 smtp_printf("501 %s: recipient address must contain a domain\r\n",
ca86f471 3639 smtp_cmd_data);
059ec3d9
PH
3640 log_write(L_smtp_syntax_error,
3641 LOG_MAIN|LOG_REJECT, "unqualified recipient rejected: "
3642 "<%s> %s%s", recipient, host_and_ident(TRUE),
3643 host_lookup_msg);
3644 break;
3645 }
3646 }
3647
3648 /* Check maximum allowed */
3649
3650 if (rcpt_count > recipients_max && recipients_max > 0)
3651 {
3652 if (recipients_max_reject)
3653 {
3654 rcpt_fail_count++;
3655 smtp_printf("552 too many recipients\r\n");
3656 if (!toomany)
3657 log_write(0, LOG_MAIN|LOG_REJECT, "too many recipients: message "
3658 "rejected: sender=<%s> %s", sender_address, host_and_ident(TRUE));
3659 }
3660 else
3661 {
3662 rcpt_defer_count++;
3663 smtp_printf("452 too many recipients\r\n");
3664 if (!toomany)
3665 log_write(0, LOG_MAIN|LOG_REJECT, "too many recipients: excess "
3666 "temporarily rejected: sender=<%s> %s", sender_address,
3667 host_and_ident(TRUE));
3668 }
3669
3670 toomany = TRUE;
3671 break;
3672 }
3673
3674 /* If we have passed the threshold for rate limiting, apply the current
3675 delay, and update it for next time, provided this is a limited host. */
3676
3677 if (rcpt_count > smtp_rlr_threshold &&
3678 verify_check_host(&smtp_ratelimit_hosts) == OK)
3679 {
3680 DEBUG(D_receive) debug_printf("rate limit RCPT: delay %.3g sec\n",
3681 smtp_delay_rcpt/1000.0);
3682 millisleep((int)smtp_delay_rcpt);
3683 smtp_delay_rcpt *= smtp_rlr_factor;
3684 if (smtp_delay_rcpt > (double)smtp_rlr_limit)
3685 smtp_delay_rcpt = (double)smtp_rlr_limit;
3686 }
3687
3688 /* If the MAIL ACL discarded all the recipients, we bypass ACL checking
a14e5636
PH
3689 for them. Otherwise, check the access control list for this recipient. As
3690 there may be a delay in this, re-check for a synchronization error
3691 afterwards, unless pipelining was advertised. */
059ec3d9 3692
a14e5636
PH
3693 if (recipients_discarded) rc = DISCARD; else
3694 {
3695 rc = acl_check(ACL_WHERE_RCPT, recipient, acl_smtp_rcpt, &user_msg,
3696 &log_msg);
3697 if (rc == OK && !pipelining_advertised && !check_sync())
3698 goto SYNC_FAILURE;
3699 }
059ec3d9
PH
3700
3701 /* The ACL was happy */
3702
3703 if (rc == OK)
3704 {
4e88a19f
PH
3705 if (user_msg == NULL) smtp_printf("250 Accepted\r\n");
3706 else smtp_user_msg(US"250", user_msg);
059ec3d9
PH
3707 receive_add_recipient(recipient, -1);
3708 }
3709
3710 /* The recipient was discarded */
3711
3712 else if (rc == DISCARD)
3713 {
4e88a19f
PH
3714 if (user_msg == NULL) smtp_printf("250 Accepted\r\n");
3715 else smtp_user_msg(US"250", user_msg);
059ec3d9
PH
3716 rcpt_fail_count++;
3717 discarded = TRUE;
3718 log_write(0, LOG_MAIN|LOG_REJECT, "%s F=<%s> rejected RCPT %s: "
3719 "discarded by %s ACL%s%s", host_and_ident(TRUE),
3720 (sender_address_unrewritten != NULL)?
3721 sender_address_unrewritten : sender_address,
3ee512ff 3722 smtp_cmd_argument, recipients_discarded? "MAIL" : "RCPT",
059ec3d9
PH
3723 (log_msg == NULL)? US"" : US": ",
3724 (log_msg == NULL)? US"" : log_msg);
3725 }
3726
3727 /* Either the ACL failed the address, or it was deferred. */
3728
3729 else
3730 {
3731 if (rc == FAIL) rcpt_fail_count++; else rcpt_defer_count++;
3732 done = smtp_handle_acl_fail(ACL_WHERE_RCPT, rc, user_msg, log_msg);
3733 }
3734 break;
3735
3736
3737 /* The DATA command is legal only if it follows successful MAIL FROM
3738 and RCPT TO commands. However, if pipelining is advertised, a bad DATA is
3739 not counted as a protocol error if it follows RCPT (which must have been
3740 rejected if there are no recipients.) This function is complete when a
3741 valid DATA command is encountered.
3742
3743 Note concerning the code used: RFC 2821 says this:
3744
3745 - If there was no MAIL, or no RCPT, command, or all such commands
3746 were rejected, the server MAY return a "command out of sequence"
3747 (503) or "no valid recipients" (554) reply in response to the
3748 DATA command.
3749
3750 The example in the pipelining RFC 2920 uses 554, but I use 503 here
2679d413
PH
3751 because it is the same whether pipelining is in use or not.
3752
3753 If all the RCPT commands that precede DATA provoked the same error message
3754 (often indicating some kind of system error), it is helpful to include it
3755 with the DATA rejection (an idea suggested by Tony Finch). */
059ec3d9
PH
3756
3757 case DATA_CMD:
b4ed4da0 3758 HAD(SCH_DATA);
059ec3d9
PH
3759 if (!discarded && recipients_count <= 0)
3760 {
2679d413
PH
3761 if (rcpt_smtp_response_same && rcpt_smtp_response != NULL)
3762 {
3763 uschar *code = US"503";
3764 int len = Ustrlen(rcpt_smtp_response);
3765 smtp_respond(code, 3, FALSE, US"All RCPT commands were rejected with "
3766 "this error:");
3767 /* Responses from smtp_printf() will have \r\n on the end */
3768 if (len > 2 && rcpt_smtp_response[len-2] == '\r')
3769 rcpt_smtp_response[len-2] = 0;
3770 smtp_respond(code, 3, FALSE, rcpt_smtp_response);
3771 }
059ec3d9 3772 if (pipelining_advertised && last_was_rcpt)
2679d413 3773 smtp_printf("503 Valid RCPT command must precede DATA\r\n");
059ec3d9
PH
3774 else
3775 done = synprot_error(L_smtp_protocol_error, 503, NULL,
3776 US"valid RCPT command must precede DATA");
3777 break;
3778 }
3779
3780 if (toomany && recipients_max_reject)
3781 {
3782 sender_address = NULL; /* This will allow a new MAIL without RSET */
3783 sender_address_unrewritten = NULL;
3784 smtp_printf("554 Too many recipients\r\n");
3785 break;
3786 }
8e669ac1 3787
a14e5636 3788 /* If there is an ACL, re-check the synchronization afterwards, since the
528fde2a
JH
3789 ACL may have delayed. To handle cutthrough delivery enforce a dummy call
3790 to get the DATA command sent. */
a14e5636 3791
528fde2a 3792 if (acl_smtp_predata == NULL && cutthrough_fd < 0) rc = OK; else
8e669ac1 3793 {
528fde2a 3794 uschar * acl= acl_smtp_predata ? acl_smtp_predata : US"accept";
5be20824 3795 enable_dollar_recipients = TRUE;
528fde2a 3796 rc = acl_check(ACL_WHERE_PREDATA, NULL, acl, &user_msg,
5be20824
PH
3797 &log_msg);
3798 enable_dollar_recipients = FALSE;
a14e5636 3799 if (rc == OK && !check_sync()) goto SYNC_FAILURE;
5be20824 3800 }
059ec3d9
PH
3801
3802 if (rc == OK)
3803 {
4e88a19f
PH
3804 if (user_msg == NULL)
3805 smtp_printf("354 Enter message, ending with \".\" on a line by itself\r\n");
3806 else smtp_user_msg(US"354", user_msg);
059ec3d9
PH