build: try to get dash/bash for sanity
[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
8d67ada3
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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,
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213#ifdef EXPERIMENTAL_PRDR
214 ENV_MAIL_OPT_PRDR,
215#endif
216 ENV_MAIL_OPT_NULL
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217 };
218typedef struct {
219 uschar * name; /* option requested during MAIL cmd */
220 int value; /* enum type */
221 BOOL need_value; /* TRUE requires value (name=value pair format)
222 FALSE is a singleton */
223 } env_mail_type_t;
224static env_mail_type_t env_mail_type_list[] = {
225 { US"SIZE", ENV_MAIL_OPT_SIZE, TRUE },
226 { US"BODY", ENV_MAIL_OPT_BODY, TRUE },
227 { US"AUTH", ENV_MAIL_OPT_AUTH, TRUE },
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228#ifdef EXPERIMENTAL_PRDR
229 { US"PRDR", ENV_MAIL_OPT_PRDR, FALSE },
230#endif
231 { US"NULL", ENV_MAIL_OPT_NULL, FALSE }
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232 };
233
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234/* When reading SMTP from a remote host, we have to use our own versions of the
235C input-reading functions, in order to be able to flush the SMTP output only
236when about to read more data from the socket. This is the only way to get
237optimal performance when the client is using pipelining. Flushing for every
238command causes a separate packet and reply packet each time; saving all the
239responses up (when pipelining) combines them into one packet and one response.
240
241For simplicity, these functions are used for *all* SMTP input, not only when
242receiving over a socket. However, after setting up a secure socket (SSL), input
243is read via the OpenSSL library, and another set of functions is used instead
244(see tls.c).
245
246These functions are set in the receive_getc etc. variables and called with the
247same interface as the C functions. However, since there can only ever be
248one incoming SMTP call, we just use a single buffer and flags. There is no need
249to implement a complicated private FILE-like structure.*/
250
251static uschar *smtp_inbuffer;
252static uschar *smtp_inptr;
253static uschar *smtp_inend;
254static int smtp_had_eof;
255static int smtp_had_error;
256
257
258/*************************************************
259* SMTP version of getc() *
260*************************************************/
261
262/* This gets the next byte from the SMTP input buffer. If the buffer is empty,
263it flushes the output, and refills the buffer, with a timeout. The signal
264handler is set appropriately by the calling function. This function is not used
265after a connection has negotated itself into an TLS/SSL state.
266
267Arguments: none
268Returns: the next character or EOF
269*/
270
271int
272smtp_getc(void)
273{
274if (smtp_inptr >= smtp_inend)
275 {
276 int rc, save_errno;
277 fflush(smtp_out);
278 if (smtp_receive_timeout > 0) alarm(smtp_receive_timeout);
279 rc = read(fileno(smtp_in), smtp_inbuffer, in_buffer_size);
280 save_errno = errno;
281 alarm(0);
282 if (rc <= 0)
283 {
284 /* Must put the error text in fixed store, because this might be during
285 header reading, where it releases unused store above the header. */
286 if (rc < 0)
287 {
288 smtp_had_error = save_errno;
289 smtp_read_error = string_copy_malloc(
290 string_sprintf(" (error: %s)", strerror(save_errno)));
291 }
292 else smtp_had_eof = 1;
293 return EOF;
294 }
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295#ifndef DISABLE_DKIM
296 dkim_exim_verify_feed(smtp_inbuffer, rc);
297#endif
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298 smtp_inend = smtp_inbuffer + rc;
299 smtp_inptr = smtp_inbuffer;
300 }
301return *smtp_inptr++;
302}
303
304
305
306/*************************************************
307* SMTP version of ungetc() *
308*************************************************/
309
310/* Puts a character back in the input buffer. Only ever
311called once.
312
313Arguments:
314 ch the character
315
316Returns: the character
317*/
318
319int
320smtp_ungetc(int ch)
321{
322*(--smtp_inptr) = ch;
323return ch;
324}
325
326
327
328
329/*************************************************
330* SMTP version of feof() *
331*************************************************/
332
333/* Tests for a previous EOF
334
335Arguments: none
336Returns: non-zero if the eof flag is set
337*/
338
339int
340smtp_feof(void)
341{
342return smtp_had_eof;
343}
344
345
346
347
348/*************************************************
349* SMTP version of ferror() *
350*************************************************/
351
352/* Tests for a previous read error, and returns with errno
353restored to what it was when the error was detected.
354
355Arguments: none
356Returns: non-zero if the error flag is set
357*/
358
359int
360smtp_ferror(void)
361{
362errno = smtp_had_error;
363return smtp_had_error;
364}
365
366
367
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368/*************************************************
369* Test for characters in the SMTP buffer *
370*************************************************/
371
372/* Used at the end of a message
373
374Arguments: none
375Returns: TRUE/FALSE
376*/
377
378BOOL
379smtp_buffered(void)
380{
381return smtp_inptr < smtp_inend;
382}
383
384
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385
386/*************************************************
387* Write formatted string to SMTP channel *
388*************************************************/
389
390/* This is a separate function so that we don't have to repeat everything for
391TLS support or debugging. It is global so that the daemon and the
392authentication functions can use it. It does not return any error indication,
393because major problems such as dropped connections won't show up till an output
394flush for non-TLS connections. The smtp_fflush() function is available for
395checking that: for convenience, TLS output errors are remembered here so that
396they are also picked up later by smtp_fflush().
397
398Arguments:
399 format format string
400 ... optional arguments
401
402Returns: nothing
403*/
404
405void
1ba28e2b 406smtp_printf(const char *format, ...)
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407{
408va_list ap;
409
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410va_start(ap, format);
411smtp_vprintf(format, ap);
412va_end(ap);
413}
414
415/* This is split off so that verify.c:respond_printf() can, in effect, call
416smtp_printf(), bearing in mind that in C a vararg function can't directly
fb08281f 417call another vararg function, only a function which accepts a va_list. */
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418
419void
1ba28e2b 420smtp_vprintf(const char *format, va_list ap)
ce552449 421{
fb08281f
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422BOOL yield;
423
424yield = string_vformat(big_buffer, big_buffer_size, format, ap);
ce552449 425
059ec3d9
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426DEBUG(D_receive)
427 {
fb08281f
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428 void *reset_point = store_get(0);
429 uschar *msg_copy, *cr, *end;
430 msg_copy = string_copy(big_buffer);
431 end = msg_copy + Ustrlen(msg_copy);
432 while ((cr = Ustrchr(msg_copy, '\r')) != NULL) /* lose CRs */
433 memmove(cr, cr + 1, (end--) - cr);
434 debug_printf("SMTP>> %s", msg_copy);
435 store_reset(reset_point);
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436 }
437
fb08281f 438if (!yield)
2679d413
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439 {
440 log_write(0, LOG_MAIN|LOG_PANIC, "string too large in smtp_printf()");
441 smtp_closedown(US"Unexpected error");
442 exim_exit(EXIT_FAILURE);
443 }
2679d413
PH
444
445/* If this is the first output for a (non-batch) RCPT command, see if all RCPTs
446have had the same. Note: this code is also present in smtp_respond(). It would
447be tidier to have it only in one place, but when it was added, it was easier to
448do it that way, so as not to have to mess with the code for the RCPT command,
449which sometimes uses smtp_printf() and sometimes smtp_respond(). */
450
451if (rcpt_in_progress)
452 {
453 if (rcpt_smtp_response == NULL)
454 rcpt_smtp_response = string_copy(big_buffer);
455 else if (rcpt_smtp_response_same &&
456 Ustrcmp(rcpt_smtp_response, big_buffer) != 0)
457 rcpt_smtp_response_same = FALSE;
458 rcpt_in_progress = FALSE;
459 }
059ec3d9 460
2679d413 461/* Now write the string */
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462
463#ifdef SUPPORT_TLS
817d9f57 464if (tls_in.active >= 0)
059ec3d9 465 {
817d9f57
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466 if (tls_write(TRUE, big_buffer, Ustrlen(big_buffer)) < 0)
467 smtp_write_error = -1;
059ec3d9
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468 }
469else
470#endif
471
2679d413 472if (fprintf(smtp_out, "%s", big_buffer) < 0) smtp_write_error = -1;
059ec3d9
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473}
474
475
476
477/*************************************************
478* Flush SMTP out and check for error *
479*************************************************/
480
481/* This function isn't currently used within Exim (it detects errors when it
482tries to read the next SMTP input), but is available for use in local_scan().
483For non-TLS connections, it flushes the output and checks for errors. For
484TLS-connections, it checks for a previously-detected TLS write error.
485
486Arguments: none
487Returns: 0 for no error; -1 after an error
488*/
489
490int
491smtp_fflush(void)
492{
817d9f57 493if (tls_in.active < 0 && fflush(smtp_out) != 0) smtp_write_error = -1;
059ec3d9
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494return smtp_write_error;
495}
496
497
498
499/*************************************************
500* SMTP command read timeout *
501*************************************************/
502
503/* Signal handler for timing out incoming SMTP commands. This attempts to
504finish off tidily.
505
506Argument: signal number (SIGALRM)
507Returns: nothing
508*/
509
510static void
511command_timeout_handler(int sig)
512{
513sig = sig; /* Keep picky compilers happy */
514log_write(L_lost_incoming_connection,
515 LOG_MAIN, "SMTP command timeout on%s connection from %s",
817d9f57 516 (tls_in.active >= 0)? " TLS" : "",
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517 host_and_ident(FALSE));
518if (smtp_batched_input)
519 moan_smtp_batch(NULL, "421 SMTP command timeout"); /* Does not return */
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520smtp_notquit_exit(US"command-timeout", US"421",
521 US"%s: SMTP command timeout - closing connection", smtp_active_hostname);
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522exim_exit(EXIT_FAILURE);
523}
524
525
526
527/*************************************************
528* SIGTERM received *
529*************************************************/
530
531/* Signal handler for handling SIGTERM. Again, try to finish tidily.
532
533Argument: signal number (SIGTERM)
534Returns: nothing
535*/
536
537static void
538command_sigterm_handler(int sig)
539{
540sig = sig; /* Keep picky compilers happy */
541log_write(0, LOG_MAIN, "%s closed after SIGTERM", smtp_get_connection_info());
542if (smtp_batched_input)
543 moan_smtp_batch(NULL, "421 SIGTERM received"); /* Does not return */
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544smtp_notquit_exit(US"signal-exit", US"421",
545 US"%s: Service not available - closing connection", smtp_active_hostname);
059ec3d9
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546exim_exit(EXIT_FAILURE);
547}
548
549
550
a14e5636 551
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552/*************************************************
553* Read one command line *
554*************************************************/
555
556/* Strictly, SMTP commands coming over the net are supposed to end with CRLF.
557There are sites that don't do this, and in any case internal SMTP probably
558should check only for LF. Consequently, we check here for LF only. The line
559ends up with [CR]LF removed from its end. If we get an overlong line, treat as
3ee512ff
PH
560an unknown command. The command is read into the global smtp_cmd_buffer so that
561it is available via $smtp_command.
059ec3d9
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562
563The character reading routine sets up a timeout for each block actually read
564from the input (which may contain more than one command). We set up a special
565signal handler that closes down the session on a timeout. Control does not
566return when it runs.
567
568Arguments:
569 check_sync if TRUE, check synchronization rules if global option is TRUE
570
571Returns: a code identifying the command (enumerated above)
572*/
573
574static int
575smtp_read_command(BOOL check_sync)
576{
577int c;
578int ptr = 0;
579smtp_cmd_list *p;
580BOOL hadnull = FALSE;
581
582os_non_restarting_signal(SIGALRM, command_timeout_handler);
583
584while ((c = (receive_getc)()) != '\n' && c != EOF)
585 {
3ee512ff 586 if (ptr >= smtp_cmd_buffer_size)
059ec3d9
PH
587 {
588 os_non_restarting_signal(SIGALRM, sigalrm_handler);
589 return OTHER_CMD;
590 }
591 if (c == 0)
592 {
593 hadnull = TRUE;
594 c = '?';
595 }
3ee512ff 596 smtp_cmd_buffer[ptr++] = c;
059ec3d9
PH
597 }
598
599receive_linecount++; /* For BSMTP errors */
600os_non_restarting_signal(SIGALRM, sigalrm_handler);
601
602/* If hit end of file, return pseudo EOF command. Whether we have a
603part-line already read doesn't matter, since this is an error state. */
604
605if (c == EOF) return EOF_CMD;
606
607/* Remove any CR and white space at the end of the line, and terminate the
608string. */
609
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610while (ptr > 0 && isspace(smtp_cmd_buffer[ptr-1])) ptr--;
611smtp_cmd_buffer[ptr] = 0;
059ec3d9 612
3ee512ff 613DEBUG(D_receive) debug_printf("SMTP<< %s\n", smtp_cmd_buffer);
059ec3d9
PH
614
615/* NULLs are not allowed in SMTP commands */
616
617if (hadnull) return BADCHAR_CMD;
618
619/* Scan command list and return identity, having set the data pointer
620to the start of the actual data characters. Check for SMTP synchronization
621if required. */
622
623for (p = cmd_list; p < cmd_list_end; p++)
624 {
084efe8d
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625 if (strncmpic(smtp_cmd_buffer, US p->name, p->len) == 0 &&
626 (smtp_cmd_buffer[p->len-1] == ':' || /* "mail from:" or "rcpt to:" */
627 smtp_cmd_buffer[p->len] == 0 ||
628 smtp_cmd_buffer[p->len] == ' '))
059ec3d9
PH
629 {
630 if (smtp_inptr < smtp_inend && /* Outstanding input */
631 p->cmd < sync_cmd_limit && /* Command should sync */
632 check_sync && /* Local flag set */
633 smtp_enforce_sync && /* Global flag set */
634 sender_host_address != NULL && /* Not local input */
635 !sender_host_notsocket) /* Really is a socket */
636 return BADSYN_CMD;
637
ca86f471
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638 /* The variables $smtp_command and $smtp_command_argument point into the
639 unmodified input buffer. A copy of the latter is taken for actual
640 processing, so that it can be chopped up into separate parts if necessary,
641 for example, when processing a MAIL command options such as SIZE that can
642 follow the sender address. */
059ec3d9 643
3ee512ff 644 smtp_cmd_argument = smtp_cmd_buffer + p->len;
ca86f471
PH
645 while (isspace(*smtp_cmd_argument)) smtp_cmd_argument++;
646 Ustrcpy(smtp_data_buffer, smtp_cmd_argument);
647 smtp_cmd_data = smtp_data_buffer;
059ec3d9
PH
648
649 /* Count non-mail commands from those hosts that are controlled in this
650 way. The default is all hosts. We don't waste effort checking the list
651 until we get a non-mail command, but then cache the result to save checking
652 again. If there's a DEFER while checking the host, assume it's in the list.
653
654 Note that one instance of RSET, EHLO/HELO, and STARTTLS is allowed at the
655 start of each incoming message by fiddling with the value in the table. */
656
657 if (!p->is_mail_cmd)
658 {
659 if (count_nonmail == TRUE_UNSET) count_nonmail =
660 verify_check_host(&smtp_accept_max_nonmail_hosts) != FAIL;
661 if (count_nonmail && ++nonmail_command_count > smtp_accept_max_nonmail)
662 return TOO_MANY_NONMAIL_CMD;
663 }
664
ca86f471
PH
665 /* If there is data for a command that does not expect it, generate the
666 error here. */
059ec3d9 667
ca86f471 668 return (p->has_arg || *smtp_cmd_data == 0)? p->cmd : BADARG_CMD;
059ec3d9
PH
669 }
670 }
671
672/* Enforce synchronization for unknown commands */
673
674if (smtp_inptr < smtp_inend && /* Outstanding input */
675 check_sync && /* Local flag set */
676 smtp_enforce_sync && /* Global flag set */
677 sender_host_address != NULL && /* Not local input */
678 !sender_host_notsocket) /* Really is a socket */
679 return BADSYN_CMD;
680
681return OTHER_CMD;
682}
683
684
685
686/*************************************************
a14e5636
PH
687* Recheck synchronization *
688*************************************************/
689
690/* Synchronization checks can never be perfect because a packet may be on its
691way but not arrived when the check is done. Such checks can in any case only be
692done when TLS is not in use. Normally, the checks happen when commands are
693read: Exim ensures that there is no more input in the input buffer. In normal
694cases, the response to the command will be fast, and there is no further check.
695
696However, for some commands an ACL is run, and that can include delays. In those
697cases, it is useful to do another check on the input just before sending the
698response. This also applies at the start of a connection. This function does
699that check by means of the select() function, as long as the facility is not
700disabled or inappropriate. A failure of select() is ignored.
701
702When there is unwanted input, we read it so that it appears in the log of the
703error.
704
705Arguments: none
706Returns: TRUE if all is well; FALSE if there is input pending
707*/
708
709static BOOL
710check_sync(void)
711{
712int fd, rc;
713fd_set fds;
714struct timeval tzero;
715
716if (!smtp_enforce_sync || sender_host_address == NULL ||
817d9f57 717 sender_host_notsocket || tls_in.active >= 0)
a14e5636
PH
718 return TRUE;
719
720fd = fileno(smtp_in);
721FD_ZERO(&fds);
722FD_SET(fd, &fds);
723tzero.tv_sec = 0;
724tzero.tv_usec = 0;
725rc = select(fd + 1, (SELECT_ARG2_TYPE *)&fds, NULL, NULL, &tzero);
726
727if (rc <= 0) return TRUE; /* Not ready to read */
728rc = smtp_getc();
729if (rc < 0) return TRUE; /* End of file or error */
730
731smtp_ungetc(rc);
732rc = smtp_inend - smtp_inptr;
733if (rc > 150) rc = 150;
734smtp_inptr[rc] = 0;
735return FALSE;
736}
737
738
739
740/*************************************************
059ec3d9
PH
741* Forced closedown of call *
742*************************************************/
743
744/* This function is called from log.c when Exim is dying because of a serious
745disaster, and also from some other places. If an incoming non-batched SMTP
746channel is open, it swallows the rest of the incoming message if in the DATA
747phase, sends the reply string, and gives an error to all subsequent commands
748except QUIT. The existence of an SMTP call is detected by the non-NULLness of
749smtp_in.
750
8f128379
PH
751Arguments:
752 message SMTP reply string to send, excluding the code
753
059ec3d9
PH
754Returns: nothing
755*/
756
757void
758smtp_closedown(uschar *message)
759{
760if (smtp_in == NULL || smtp_batched_input) return;
761receive_swallow_smtp();
762smtp_printf("421 %s\r\n", message);
763
764for (;;)
765 {
766 switch(smtp_read_command(FALSE))
767 {
768 case EOF_CMD:
769 return;
770
771 case QUIT_CMD:
772 smtp_printf("221 %s closing connection\r\n", smtp_active_hostname);
773 mac_smtp_fflush();
774 return;
775
776 case RSET_CMD:
777 smtp_printf("250 Reset OK\r\n");
778 break;
779
780 default:
781 smtp_printf("421 %s\r\n", message);
782 break;
783 }
784 }
785}
786
787
788
789
790/*************************************************
791* Set up connection info for logging *
792*************************************************/
793
794/* This function is called when logging information about an SMTP connection.
795It sets up appropriate source information, depending on the type of connection.
dac79d3e
PH
796If sender_fullhost is NULL, we are at a very early stage of the connection;
797just use the IP address.
059ec3d9
PH
798
799Argument: none
800Returns: a string describing the connection
801*/
802
803uschar *
804smtp_get_connection_info(void)
805{
dac79d3e
PH
806uschar *hostname = (sender_fullhost == NULL)?
807 sender_host_address : sender_fullhost;
808
059ec3d9 809if (host_checking)
dac79d3e 810 return string_sprintf("SMTP connection from %s", hostname);
059ec3d9
PH
811
812if (sender_host_unknown || sender_host_notsocket)
813 return string_sprintf("SMTP connection from %s", sender_ident);
814
815if (is_inetd)
dac79d3e 816 return string_sprintf("SMTP connection from %s (via inetd)", hostname);
059ec3d9
PH
817
818if ((log_extra_selector & LX_incoming_interface) != 0 &&
819 interface_address != NULL)
dac79d3e 820 return string_sprintf("SMTP connection from %s I=[%s]:%d", hostname,
059ec3d9
PH
821 interface_address, interface_port);
822
dac79d3e 823return string_sprintf("SMTP connection from %s", hostname);
059ec3d9
PH
824}
825
826
827
828/*************************************************
b4ed4da0
PH
829* Log lack of MAIL if so configured *
830*************************************************/
831
832/* This function is called when an SMTP session ends. If the log selector
833smtp_no_mail is set, write a log line giving some details of what has happened
834in the SMTP session.
835
836Arguments: none
837Returns: nothing
838*/
839
840void
841smtp_log_no_mail(void)
842{
843int size, ptr, i;
844uschar *s, *sep;
845
846if (smtp_mailcmd_count > 0 || (log_extra_selector & LX_smtp_no_mail) == 0)
847 return;
848
849s = NULL;
850size = ptr = 0;
851
852if (sender_host_authenticated != NULL)
853 {
854 s = string_append(s, &size, &ptr, 2, US" A=", sender_host_authenticated);
855 if (authenticated_id != NULL)
856 s = string_append(s, &size, &ptr, 2, US":", authenticated_id);
857 }
858
859#ifdef SUPPORT_TLS
817d9f57
JH
860if ((log_extra_selector & LX_tls_cipher) != 0 && tls_in.cipher != NULL)
861 s = string_append(s, &size, &ptr, 2, US" X=", tls_in.cipher);
b4ed4da0 862if ((log_extra_selector & LX_tls_certificate_verified) != 0 &&
817d9f57 863 tls_in.cipher != NULL)
b4ed4da0 864 s = string_append(s, &size, &ptr, 2, US" CV=",
817d9f57
JH
865 tls_in.certificate_verified? "yes":"no");
866if ((log_extra_selector & LX_tls_peerdn) != 0 && tls_in.peerdn != NULL)
48ed62d9 867 s = string_append(s, &size, &ptr, 3, US" DN=\"",
817d9f57
JH
868 string_printing(tls_in.peerdn), US"\"");
869if ((log_extra_selector & LX_tls_sni) != 0 && tls_in.sni != NULL)
3f0945ff 870 s = string_append(s, &size, &ptr, 3, US" SNI=\"",
817d9f57 871 string_printing(tls_in.sni), US"\"");
3f0945ff 872#endif
b4ed4da0
PH
873
874sep = (smtp_connection_had[SMTP_HBUFF_SIZE-1] != SCH_NONE)?
875 US" C=..." : US" C=";
876for (i = smtp_ch_index; i < SMTP_HBUFF_SIZE; i++)
877 {
878 if (smtp_connection_had[i] != SCH_NONE)
879 {
880 s = string_append(s, &size, &ptr, 2, sep,
881 smtp_names[smtp_connection_had[i]]);
882 sep = US",";
883 }
884 }
885
886for (i = 0; i < smtp_ch_index; i++)
887 {
888 s = string_append(s, &size, &ptr, 2, sep, smtp_names[smtp_connection_had[i]]);
889 sep = US",";
890 }
891
892if (s != NULL) s[ptr] = 0; else s = US"";
893log_write(0, LOG_MAIN, "no MAIL in SMTP connection from %s D=%s%s",
894 host_and_ident(FALSE),
895 readconf_printtime(time(NULL) - smtp_connection_start), s);
896}
897
898
899
900/*************************************************
059ec3d9
PH
901* Check HELO line and set sender_helo_name *
902*************************************************/
903
904/* Check the format of a HELO line. The data for HELO/EHLO is supposed to be
905the domain name of the sending host, or an ip literal in square brackets. The
906arrgument is placed in sender_helo_name, which is in malloc store, because it
907must persist over multiple incoming messages. If helo_accept_junk is set, this
908host is permitted to send any old junk (needed for some broken hosts).
909Otherwise, helo_allow_chars can be used for rogue characters in general
910(typically people want to let in underscores).
911
912Argument:
913 s the data portion of the line (already past any white space)
914
915Returns: TRUE or FALSE
916*/
917
918static BOOL
919check_helo(uschar *s)
920{
921uschar *start = s;
922uschar *end = s + Ustrlen(s);
923BOOL yield = helo_accept_junk;
924
925/* Discard any previous helo name */
926
927if (sender_helo_name != NULL)
928 {
929 store_free(sender_helo_name);
930 sender_helo_name = NULL;
931 }
932
933/* Skip tests if junk is permitted. */
934
935if (!yield)
936 {
937 /* Allow the new standard form for IPv6 address literals, namely,
938 [IPv6:....], and because someone is bound to use it, allow an equivalent
939 IPv4 form. Allow plain addresses as well. */
940
941 if (*s == '[')
942 {
943 if (end[-1] == ']')
944 {
945 end[-1] = 0;
946 if (strncmpic(s, US"[IPv6:", 6) == 0)
947 yield = (string_is_ip_address(s+6, NULL) == 6);
948 else if (strncmpic(s, US"[IPv4:", 6) == 0)
949 yield = (string_is_ip_address(s+6, NULL) == 4);
950 else
951 yield = (string_is_ip_address(s+1, NULL) != 0);
952 end[-1] = ']';
953 }
954 }
955
956 /* Non-literals must be alpha, dot, hyphen, plus any non-valid chars
957 that have been configured (usually underscore - sigh). */
958
959 else if (*s != 0)
960 {
961 yield = TRUE;
962 while (*s != 0)
963 {
964 if (!isalnum(*s) && *s != '.' && *s != '-' &&
965 Ustrchr(helo_allow_chars, *s) == NULL)
966 {
967 yield = FALSE;
968 break;
969 }
970 s++;
971 }
972 }
973 }
974
975/* Save argument if OK */
976
977if (yield) sender_helo_name = string_copy_malloc(start);
978return yield;
979}
980
981
982
983
984
985/*************************************************
986* Extract SMTP command option *
987*************************************************/
988
ca86f471 989/* This function picks the next option setting off the end of smtp_cmd_data. It
059ec3d9
PH
990is called for MAIL FROM and RCPT TO commands, to pick off the optional ESMTP
991things that can appear there.
992
993Arguments:
994 name point this at the name
995 value point this at the data string
996
997Returns: TRUE if found an option
998*/
999
1000static BOOL
1001extract_option(uschar **name, uschar **value)
1002{
1003uschar *n;
ca86f471 1004uschar *v = smtp_cmd_data + Ustrlen(smtp_cmd_data) - 1;
059ec3d9
PH
1005while (isspace(*v)) v--;
1006v[1] = 0;
ca86f471 1007while (v > smtp_cmd_data && *v != '=' && !isspace(*v)) v--;
059ec3d9
PH
1008
1009n = v;
fd98a5c6
JH
1010if (*v == '=')
1011{
1012 while(isalpha(n[-1])) n--;
1013 /* RFC says SP, but TAB seen in wild and other major MTAs accept it */
1014 if (!isspace(n[-1])) return FALSE;
1015 n[-1] = 0;
1016}
1017else
1018{
1019 n++;
1020 if (v == smtp_cmd_data) return FALSE;
1021}
059ec3d9 1022*v++ = 0;
fd98a5c6 1023*name = n;
059ec3d9
PH
1024*value = v;
1025return TRUE;
1026}
1027
1028
1029
1030
1031
059ec3d9
PH
1032/*************************************************
1033* Reset for new message *
1034*************************************************/
1035
1036/* This function is called whenever the SMTP session is reset from
1037within either of the setup functions.
1038
1039Argument: the stacking pool storage reset point
1040Returns: nothing
1041*/
1042
1043static void
1044smtp_reset(void *reset_point)
1045{
059ec3d9
PH
1046store_reset(reset_point);
1047recipients_list = NULL;
1048rcpt_count = rcpt_defer_count = rcpt_fail_count =
1049 raw_recipients_count = recipients_count = recipients_list_max = 0;
2e5b33cd 1050cancel_cutthrough_connection("smtp reset");
2e0c1448 1051message_linecount = 0;
059ec3d9 1052message_size = -1;
71fafd95 1053acl_added_headers = NULL;
e7568d51 1054acl_removed_headers = NULL;
059ec3d9 1055queue_only_policy = FALSE;
2679d413
PH
1056rcpt_smtp_response = NULL;
1057rcpt_smtp_response_same = TRUE;
1058rcpt_in_progress = FALSE;
69358f02 1059deliver_freeze = FALSE; /* Can be set by ACL */
6a3f1455 1060freeze_tell = freeze_tell_config; /* Can be set by ACL */
29aba418 1061fake_response = OK; /* Can be set by ACL */
6951ac6c 1062#ifdef WITH_CONTENT_SCAN
8523533c
TK
1063no_mbox_unspool = FALSE; /* Can be set by ACL */
1064#endif
69358f02 1065submission_mode = FALSE; /* Can be set by ACL */
f4ee74ac 1066suppress_local_fixups = suppress_local_fixups_default; /* Can be set by ACL */
69358f02
PH
1067active_local_from_check = local_from_check; /* Can be set by ACL */
1068active_local_sender_retain = local_sender_retain; /* Can be set by ACL */
059ec3d9 1069sender_address = NULL;
2fe1a124 1070submission_name = NULL; /* Can be set by ACL */
059ec3d9
PH
1071raw_sender = NULL; /* After SMTP rewrite, before qualifying */
1072sender_address_unrewritten = NULL; /* Set only after verify rewrite */
1073sender_verified_list = NULL; /* No senders verified */
1074memset(sender_address_cache, 0, sizeof(sender_address_cache));
1075memset(sender_domain_cache, 0, sizeof(sender_domain_cache));
1076authenticated_sender = NULL;
8523533c
TK
1077#ifdef EXPERIMENTAL_BRIGHTMAIL
1078bmi_run = 0;
1079bmi_verdicts = NULL;
1080#endif
80a47a2c 1081#ifndef DISABLE_DKIM
9e5d6b55 1082dkim_signers = NULL;
80a47a2c
TK
1083dkim_disable_verify = FALSE;
1084dkim_collect_input = FALSE;
f7572e5a 1085#endif
8523533c
TK
1086#ifdef EXPERIMENTAL_SPF
1087spf_header_comment = NULL;
1088spf_received = NULL;
8e669ac1 1089spf_result = NULL;
8523533c
TK
1090spf_smtp_comment = NULL;
1091#endif
059ec3d9
PH
1092body_linecount = body_zerocount = 0;
1093
870f6ba8
TF
1094sender_rate = sender_rate_limit = sender_rate_period = NULL;
1095ratelimiters_mail = NULL; /* Updated by ratelimit ACL condition */
1096 /* Note that ratelimiters_conn persists across resets. */
1097
38a0a95f 1098/* Reset message ACL variables */
47ca6d6c 1099
38a0a95f 1100acl_var_m = NULL;
059ec3d9
PH
1101
1102/* The message body variables use malloc store. They may be set if this is
1103not the first message in an SMTP session and the previous message caused them
1104to be referenced in an ACL. */
1105
1106if (message_body != NULL)
1107 {
1108 store_free(message_body);
1109 message_body = NULL;
1110 }
1111
1112if (message_body_end != NULL)
1113 {
1114 store_free(message_body_end);
1115 message_body_end = NULL;
1116 }
1117
1118/* Warning log messages are also saved in malloc store. They are saved to avoid
1119repetition in the same message, but it seems right to repeat them for different
4e88a19f 1120messages. */
059ec3d9
PH
1121
1122while (acl_warn_logged != NULL)
1123 {
1124 string_item *this = acl_warn_logged;
1125 acl_warn_logged = acl_warn_logged->next;
1126 store_free(this);
1127 }
1128}
1129
1130
1131
1132
1133
1134/*************************************************
1135* Initialize for incoming batched SMTP message *
1136*************************************************/
1137
1138/* This function is called from smtp_setup_msg() in the case when
1139smtp_batched_input is true. This happens when -bS is used to pass a whole batch
1140of messages in one file with SMTP commands between them. All errors must be
1141reported by sending a message, and only MAIL FROM, RCPT TO, and DATA are
1142relevant. After an error on a sender, or an invalid recipient, the remainder
1143of the message is skipped. The value of received_protocol is already set.
1144
1145Argument: none
1146Returns: > 0 message successfully started (reached DATA)
1147 = 0 QUIT read or end of file reached
1148 < 0 should not occur
1149*/
1150
1151static int
1152smtp_setup_batch_msg(void)
1153{
1154int done = 0;
1155void *reset_point = store_get(0);
1156
1157/* Save the line count at the start of each transaction - single commands
1158like HELO and RSET count as whole transactions. */
1159
1160bsmtp_transaction_linecount = receive_linecount;
1161
1162if ((receive_feof)()) return 0; /* Treat EOF as QUIT */
1163
1164smtp_reset(reset_point); /* Reset for start of message */
1165
1166/* Deal with SMTP commands. This loop is exited by setting done to a POSITIVE
1167value. The values are 2 larger than the required yield of the function. */
1168
1169while (done <= 0)
1170 {
1171 uschar *errmess;
1172 uschar *recipient = NULL;
1173 int start, end, sender_domain, recipient_domain;
1174
1175 switch(smtp_read_command(FALSE))
1176 {
1177 /* The HELO/EHLO commands set sender_address_helo if they have
1178 valid data; otherwise they are ignored, except that they do
1179 a reset of the state. */
1180
1181 case HELO_CMD:
1182 case EHLO_CMD:
1183
ca86f471 1184 check_helo(smtp_cmd_data);
059ec3d9
PH
1185 /* Fall through */
1186
1187 case RSET_CMD:
1188 smtp_reset(reset_point);
1189 bsmtp_transaction_linecount = receive_linecount;
1190 break;
1191
1192
1193 /* The MAIL FROM command requires an address as an operand. All we
1194 do here is to parse it for syntactic correctness. The form "<>" is
1195 a special case which converts into an empty string. The start/end
1196 pointers in the original are not used further for this address, as
1197 it is the canonical extracted address which is all that is kept. */
1198
1199 case MAIL_CMD:
1200 if (sender_address != NULL)
1201 /* The function moan_smtp_batch() does not return. */
3ee512ff 1202 moan_smtp_batch(smtp_cmd_buffer, "503 Sender already given");
059ec3d9 1203
ca86f471 1204 if (smtp_cmd_data[0] == 0)
059ec3d9 1205 /* The function moan_smtp_batch() does not return. */
3ee512ff 1206 moan_smtp_batch(smtp_cmd_buffer, "501 MAIL FROM must have an address operand");
059ec3d9
PH
1207
1208 /* Reset to start of message */
1209
1210 smtp_reset(reset_point);
1211
1212 /* Apply SMTP rewrite */
1213
1214 raw_sender = ((rewrite_existflags & rewrite_smtp) != 0)?
ca86f471
PH
1215 rewrite_one(smtp_cmd_data, rewrite_smtp|rewrite_smtp_sender, NULL, FALSE,
1216 US"", global_rewrite_rules) : smtp_cmd_data;
059ec3d9
PH
1217
1218 /* Extract the address; the TRUE flag allows <> as valid */
1219
1220 raw_sender =
1221 parse_extract_address(raw_sender, &errmess, &start, &end, &sender_domain,
1222 TRUE);
1223
1224 if (raw_sender == NULL)
1225 /* The function moan_smtp_batch() does not return. */
3ee512ff 1226 moan_smtp_batch(smtp_cmd_buffer, "501 %s", errmess);
059ec3d9
PH
1227
1228 sender_address = string_copy(raw_sender);
1229
1230 /* Qualify unqualified sender addresses if permitted to do so. */
1231
1232 if (sender_domain == 0 && sender_address[0] != 0 && sender_address[0] != '@')
1233 {
1234 if (allow_unqualified_sender)
1235 {
1236 sender_address = rewrite_address_qualify(sender_address, FALSE);
1237 DEBUG(D_receive) debug_printf("unqualified address %s accepted "
1238 "and rewritten\n", raw_sender);
1239 }
1240 /* The function moan_smtp_batch() does not return. */
3ee512ff 1241 else moan_smtp_batch(smtp_cmd_buffer, "501 sender address must contain "
059ec3d9
PH
1242 "a domain");
1243 }
1244 break;
1245
1246
1247 /* The RCPT TO command requires an address as an operand. All we do
1248 here is to parse it for syntactic correctness. There may be any number
1249 of RCPT TO commands, specifying multiple senders. We build them all into
1250 a data structure that is in argc/argv format. The start/end values
1251 given by parse_extract_address are not used, as we keep only the
1252 extracted address. */
1253
1254 case RCPT_CMD:
1255 if (sender_address == NULL)
1256 /* The function moan_smtp_batch() does not return. */
3ee512ff 1257 moan_smtp_batch(smtp_cmd_buffer, "503 No sender yet given");
059ec3d9 1258
ca86f471 1259 if (smtp_cmd_data[0] == 0)
059ec3d9 1260 /* The function moan_smtp_batch() does not return. */
3ee512ff 1261 moan_smtp_batch(smtp_cmd_buffer, "501 RCPT TO must have an address operand");
059ec3d9
PH
1262
1263 /* Check maximum number allowed */
1264
1265 if (recipients_max > 0 && recipients_count + 1 > recipients_max)
1266 /* The function moan_smtp_batch() does not return. */
3ee512ff 1267 moan_smtp_batch(smtp_cmd_buffer, "%s too many recipients",
059ec3d9
PH
1268 recipients_max_reject? "552": "452");
1269
1270 /* Apply SMTP rewrite, then extract address. Don't allow "<>" as a
1271 recipient address */
1272
1273 recipient = ((rewrite_existflags & rewrite_smtp) != 0)?
ca86f471
PH
1274 rewrite_one(smtp_cmd_data, rewrite_smtp, NULL, FALSE, US"",
1275 global_rewrite_rules) : smtp_cmd_data;
059ec3d9
PH
1276
1277 /* rfc821_domains = TRUE; << no longer needed */
1278 recipient = parse_extract_address(recipient, &errmess, &start, &end,
1279 &recipient_domain, FALSE);
1280 /* rfc821_domains = FALSE; << no longer needed */
1281
1282 if (recipient == NULL)
1283 /* The function moan_smtp_batch() does not return. */
3ee512ff 1284 moan_smtp_batch(smtp_cmd_buffer, "501 %s", errmess);
059ec3d9
PH
1285
1286 /* If the recipient address is unqualified, qualify it if permitted. Then
1287 add it to the list of recipients. */
1288
1289 if (recipient_domain == 0)
1290 {
1291 if (allow_unqualified_recipient)
1292 {
1293 DEBUG(D_receive) debug_printf("unqualified address %s accepted\n",
1294 recipient);
1295 recipient = rewrite_address_qualify(recipient, TRUE);
1296 }
1297 /* The function moan_smtp_batch() does not return. */
3ee512ff 1298 else moan_smtp_batch(smtp_cmd_buffer, "501 recipient address must contain "
059ec3d9
PH
1299 "a domain");
1300 }
1301 receive_add_recipient(recipient, -1);
1302 break;
1303
1304
1305 /* The DATA command is legal only if it follows successful MAIL FROM
1306 and RCPT TO commands. This function is complete when a valid DATA
1307 command is encountered. */
1308
1309 case DATA_CMD:
1310 if (sender_address == NULL || recipients_count <= 0)
1311 {
1312 /* The function moan_smtp_batch() does not return. */
1313 if (sender_address == NULL)
3ee512ff 1314 moan_smtp_batch(smtp_cmd_buffer,
059ec3d9
PH
1315 "503 MAIL FROM:<sender> command must precede DATA");
1316 else
3ee512ff 1317 moan_smtp_batch(smtp_cmd_buffer,
059ec3d9
PH
1318 "503 RCPT TO:<recipient> must precede DATA");
1319 }
1320 else
1321 {
1322 done = 3; /* DATA successfully achieved */
1323 message_ended = END_NOTENDED; /* Indicate in middle of message */
1324 }
1325 break;
1326
1327
1328 /* The VRFY, EXPN, HELP, ETRN, and NOOP commands are ignored. */
1329
1330 case VRFY_CMD:
1331 case EXPN_CMD:
1332 case HELP_CMD:
1333 case NOOP_CMD:
1334 case ETRN_CMD:
1335 bsmtp_transaction_linecount = receive_linecount;
1336 break;
1337
1338
1339 case EOF_CMD:
1340 case QUIT_CMD:
1341 done = 2;
1342 break;
1343
1344
1345 case BADARG_CMD:
1346 /* The function moan_smtp_batch() does not return. */
3ee512ff 1347 moan_smtp_batch(smtp_cmd_buffer, "501 Unexpected argument data");
059ec3d9
PH
1348 break;
1349
1350
1351 case BADCHAR_CMD:
1352 /* The function moan_smtp_batch() does not return. */
3ee512ff 1353 moan_smtp_batch(smtp_cmd_buffer, "501 Unexpected NULL in SMTP command");
059ec3d9
PH
1354 break;
1355
1356
1357 default:
1358 /* The function moan_smtp_batch() does not return. */
3ee512ff 1359 moan_smtp_batch(smtp_cmd_buffer, "500 Command unrecognized");
059ec3d9
PH
1360 break;
1361 }
1362 }
1363
1364return done - 2; /* Convert yield values */
1365}
1366
1367
1368
1369
1370/*************************************************
1371* Start an SMTP session *
1372*************************************************/
1373
1374/* This function is called at the start of an SMTP session. Thereafter,
1375smtp_setup_msg() is called to initiate each separate message. This
1376function does host-specific testing, and outputs the banner line.
1377
1378Arguments: none
1379Returns: FALSE if the session can not continue; something has
1380 gone wrong, or the connection to the host is blocked
1381*/
1382
1383BOOL
1384smtp_start_session(void)
1385{
1386int size = 256;
4e88a19f
PH
1387int ptr, esclen;
1388uschar *user_msg, *log_msg;
1389uschar *code, *esc;
059ec3d9
PH
1390uschar *p, *s, *ss;
1391
b4ed4da0
PH
1392smtp_connection_start = time(NULL);
1393for (smtp_ch_index = 0; smtp_ch_index < SMTP_HBUFF_SIZE; smtp_ch_index++)
1394 smtp_connection_had[smtp_ch_index] = SCH_NONE;
1395smtp_ch_index = 0;
1396
00f00ca5
PH
1397/* Default values for certain variables */
1398
059ec3d9 1399helo_seen = esmtp = helo_accept_junk = FALSE;
b4ed4da0 1400smtp_mailcmd_count = 0;
059ec3d9
PH
1401count_nonmail = TRUE_UNSET;
1402synprot_error_count = unknown_command_count = nonmail_command_count = 0;
1403smtp_delay_mail = smtp_rlm_base;
1404auth_advertised = FALSE;
1405pipelining_advertised = FALSE;
cf8b11a5 1406pipelining_enable = TRUE;
059ec3d9 1407sync_cmd_limit = NON_SYNC_CMD_NON_PIPELINING;
8f128379 1408smtp_exit_function_called = FALSE; /* For avoiding loop in not-quit exit */
059ec3d9
PH
1409
1410memset(sender_host_cache, 0, sizeof(sender_host_cache));
1411
33d73e3b
PH
1412/* If receiving by -bs from a trusted user, or testing with -bh, we allow
1413authentication settings from -oMaa to remain in force. */
1414
1415if (!host_checking && !sender_host_notsocket) sender_host_authenticated = NULL;
059ec3d9
PH
1416authenticated_by = NULL;
1417
1418#ifdef SUPPORT_TLS
817d9f57 1419tls_in.cipher = tls_in.peerdn = NULL;
059ec3d9
PH
1420tls_advertised = FALSE;
1421#endif
1422
1423/* Reset ACL connection variables */
1424
38a0a95f 1425acl_var_c = NULL;
059ec3d9 1426
ca86f471 1427/* Allow for trailing 0 in the command and data buffers. */
3ee512ff 1428
ca86f471 1429smtp_cmd_buffer = (uschar *)malloc(2*smtp_cmd_buffer_size + 2);
3ee512ff 1430if (smtp_cmd_buffer == NULL)
059ec3d9
PH
1431 log_write(0, LOG_MAIN|LOG_PANIC_DIE,
1432 "malloc() failed for SMTP command buffer");
2416c261 1433smtp_cmd_buffer[0] = 0;
ca86f471 1434smtp_data_buffer = smtp_cmd_buffer + smtp_cmd_buffer_size + 1;
059ec3d9
PH
1435
1436/* For batched input, the protocol setting can be overridden from the
1437command line by a trusted caller. */
1438
1439if (smtp_batched_input)
1440 {
1441 if (received_protocol == NULL) received_protocol = US"local-bsmtp";
1442 }
1443
1444/* For non-batched SMTP input, the protocol setting is forced here. It will be
1445reset later if any of EHLO/AUTH/STARTTLS are received. */
1446
1447else
1448 received_protocol =
1449 protocols[pnormal] + ((sender_host_address != NULL)? pnlocal : 0);
1450
1451/* Set up the buffer for inputting using direct read() calls, and arrange to
1452call the local functions instead of the standard C ones. */
1453
1454smtp_inbuffer = (uschar *)malloc(in_buffer_size);
1455if (smtp_inbuffer == NULL)
1456 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "malloc() failed for SMTP input buffer");
1457receive_getc = smtp_getc;
1458receive_ungetc = smtp_ungetc;
1459receive_feof = smtp_feof;
1460receive_ferror = smtp_ferror;
58eb016e 1461receive_smtp_buffered = smtp_buffered;
059ec3d9
PH
1462smtp_inptr = smtp_inend = smtp_inbuffer;
1463smtp_had_eof = smtp_had_error = 0;
1464
1465/* Set up the message size limit; this may be host-specific */
1466
d45b1de8
PH
1467thismessage_size_limit = expand_string_integer(message_size_limit, TRUE);
1468if (expand_string_message != NULL)
059ec3d9
PH
1469 {
1470 if (thismessage_size_limit == -1)
1471 log_write(0, LOG_MAIN|LOG_PANIC, "unable to expand message_size_limit: "
1472 "%s", expand_string_message);
1473 else
1474 log_write(0, LOG_MAIN|LOG_PANIC, "invalid message_size_limit: "
1475 "%s", expand_string_message);
1476 smtp_closedown(US"Temporary local problem - please try later");
1477 return FALSE;
1478 }
1479
1480/* When a message is input locally via the -bs or -bS options, sender_host_
1481unknown is set unless -oMa was used to force an IP address, in which case it
1482is checked like a real remote connection. When -bs is used from inetd, this
1483flag is not set, causing the sending host to be checked. The code that deals
1484with IP source routing (if configured) is never required for -bs or -bS and
1485the flag sender_host_notsocket is used to suppress it.
1486
1487If smtp_accept_max and smtp_accept_reserve are set, keep some connections in
1488reserve for certain hosts and/or networks. */
1489
1490if (!sender_host_unknown)
1491 {
1492 int rc;
1493 BOOL reserved_host = FALSE;
1494
1495 /* Look up IP options (source routing info) on the socket if this is not an
1496 -oMa "host", and if any are found, log them and drop the connection.
1497
1498 Linux (and others now, see below) is different to everyone else, so there
1499 has to be some conditional compilation here. Versions of Linux before 2.1.15
1500 used a structure whose name was "options". Somebody finally realized that
1501 this name was silly, and it got changed to "ip_options". I use the
1502 newer name here, but there is a fudge in the script that sets up os.h
1503 to define a macro in older Linux systems.
1504
1505 Sigh. Linux is a fast-moving target. Another generation of Linux uses
1506 glibc 2, which has chosen ip_opts for the structure name. This is now
1507 really a glibc thing rather than a Linux thing, so the condition name
1508 has been changed to reflect this. It is relevant also to GNU/Hurd.
1509
1510 Mac OS 10.x (Darwin) is like the later glibc versions, but without the
1511 setting of the __GLIBC__ macro, so we can't detect it automatically. There's
1512 a special macro defined in the os.h file.
1513
1514 Some DGUX versions on older hardware appear not to support IP options at
1515 all, so there is now a general macro which can be set to cut out this
1516 support altogether.
1517
1518 How to do this properly in IPv6 is not yet known. */
1519
1520 #if !HAVE_IPV6 && !defined(NO_IP_OPTIONS)
1521
1522 #ifdef GLIBC_IP_OPTIONS
1523 #if (!defined __GLIBC__) || (__GLIBC__ < 2)
1524 #define OPTSTYLE 1
1525 #else
1526 #define OPTSTYLE 2
1527 #endif
1528 #elif defined DARWIN_IP_OPTIONS
1529 #define OPTSTYLE 2
1530 #else
1531 #define OPTSTYLE 3
1532 #endif
1533
1534 if (!host_checking && !sender_host_notsocket)
1535 {
1536 #if OPTSTYLE == 1
36a3b041 1537 EXIM_SOCKLEN_T optlen = sizeof(struct ip_options) + MAX_IPOPTLEN;
059ec3d9
PH
1538 struct ip_options *ipopt = store_get(optlen);
1539 #elif OPTSTYLE == 2
1540 struct ip_opts ipoptblock;
1541 struct ip_opts *ipopt = &ipoptblock;
36a3b041 1542 EXIM_SOCKLEN_T optlen = sizeof(ipoptblock);
059ec3d9
PH
1543 #else
1544 struct ipoption ipoptblock;
1545 struct ipoption *ipopt = &ipoptblock;
36a3b041 1546 EXIM_SOCKLEN_T optlen = sizeof(ipoptblock);
059ec3d9
PH
1547 #endif
1548
1549 /* Occasional genuine failures of getsockopt() have been seen - for
1550 example, "reset by peer". Therefore, just log and give up on this
1551 call, unless the error is ENOPROTOOPT. This error is given by systems
1552 that have the interfaces but not the mechanism - e.g. GNU/Hurd at the time
1553 of writing. So for that error, carry on - we just can't do an IP options
1554 check. */
1555
1556 DEBUG(D_receive) debug_printf("checking for IP options\n");
1557
1558 if (getsockopt(fileno(smtp_out), IPPROTO_IP, IP_OPTIONS, (uschar *)(ipopt),
1559 &optlen) < 0)
1560 {
1561 if (errno != ENOPROTOOPT)
1562 {
1563 log_write(0, LOG_MAIN, "getsockopt() failed from %s: %s",
1564 host_and_ident(FALSE), strerror(errno));
1565 smtp_printf("451 SMTP service not available\r\n");
1566 return FALSE;
1567 }
1568 }
1569
1570 /* Deal with any IP options that are set. On the systems I have looked at,
1571 the value of MAX_IPOPTLEN has been 40, meaning that there should never be
1572 more logging data than will fit in big_buffer. Nevertheless, after somebody
1573 questioned this code, I've added in some paranoid checking. */
1574
1575 else if (optlen > 0)
1576 {
1577 uschar *p = big_buffer;
1578 uschar *pend = big_buffer + big_buffer_size;
1579 uschar *opt, *adptr;
1580 int optcount;
1581 struct in_addr addr;
1582
1583 #if OPTSTYLE == 1
1584 uschar *optstart = (uschar *)(ipopt->__data);
1585 #elif OPTSTYLE == 2
1586 uschar *optstart = (uschar *)(ipopt->ip_opts);
1587 #else
1588 uschar *optstart = (uschar *)(ipopt->ipopt_list);
1589 #endif
1590
1591 DEBUG(D_receive) debug_printf("IP options exist\n");
1592
1593 Ustrcpy(p, "IP options on incoming call:");
1594 p += Ustrlen(p);
1595
1596 for (opt = optstart; opt != NULL &&
1597 opt < (uschar *)(ipopt) + optlen;)
1598 {
1599 switch (*opt)
1600 {
1601 case IPOPT_EOL:
1602 opt = NULL;
1603 break;
1604
1605 case IPOPT_NOP:
1606 opt++;
1607 break;
1608
1609 case IPOPT_SSRR:
1610 case IPOPT_LSRR:
1611 if (!string_format(p, pend-p, " %s [@%s",
1612 (*opt == IPOPT_SSRR)? "SSRR" : "LSRR",
1613 #if OPTSTYLE == 1
1614 inet_ntoa(*((struct in_addr *)(&(ipopt->faddr))))))
1615 #elif OPTSTYLE == 2
1616 inet_ntoa(ipopt->ip_dst)))
1617 #else
1618 inet_ntoa(ipopt->ipopt_dst)))
1619 #endif
1620 {
1621 opt = NULL;
1622 break;
1623 }
1624
1625 p += Ustrlen(p);
1626 optcount = (opt[1] - 3) / sizeof(struct in_addr);
1627 adptr = opt + 3;
1628 while (optcount-- > 0)
1629 {
1630 memcpy(&addr, adptr, sizeof(addr));
1631 if (!string_format(p, pend - p - 1, "%s%s",
1632 (optcount == 0)? ":" : "@", inet_ntoa(addr)))
1633 {
1634 opt = NULL;
1635 break;
1636 }
1637 p += Ustrlen(p);
1638 adptr += sizeof(struct in_addr);
1639 }
1640 *p++ = ']';
1641 opt += opt[1];
1642 break;
1643
1644 default:
1645 {
1646 int i;
1647 if (pend - p < 4 + 3*opt[1]) { opt = NULL; break; }
1648 Ustrcat(p, "[ ");
1649 p += 2;
1650 for (i = 0; i < opt[1]; i++)
1651 {
1652 sprintf(CS p, "%2.2x ", opt[i]);
1653 p += 3;
1654 }
1655 *p++ = ']';
1656 }
1657 opt += opt[1];
1658 break;
1659 }
1660 }
1661
1662 *p = 0;
1663 log_write(0, LOG_MAIN, "%s", big_buffer);
1664
1665 /* Refuse any call with IP options. This is what tcpwrappers 7.5 does. */
1666
1667 log_write(0, LOG_MAIN|LOG_REJECT,
1668 "connection from %s refused (IP options)", host_and_ident(FALSE));
1669
1670 smtp_printf("554 SMTP service not available\r\n");
1671 return FALSE;
1672 }
1673
1674 /* Length of options = 0 => there are no options */
1675
1676 else DEBUG(D_receive) debug_printf("no IP options found\n");
1677 }
1678 #endif /* HAVE_IPV6 && !defined(NO_IP_OPTIONS) */
1679
1680 /* Set keep-alive in socket options. The option is on by default. This
1681 setting is an attempt to get rid of some hanging connections that stick in
1682 read() when the remote end (usually a dialup) goes away. */
1683
1684 if (smtp_accept_keepalive && !sender_host_notsocket)
1685 ip_keepalive(fileno(smtp_out), sender_host_address, FALSE);
1686
1687 /* If the current host matches host_lookup, set the name by doing a
1688 reverse lookup. On failure, sender_host_name will be NULL and
1689 host_lookup_failed will be TRUE. This may or may not be serious - optional
1690 checks later. */
1691
1692 if (verify_check_host(&host_lookup) == OK)
1693 {
1694 (void)host_name_lookup();
1695 host_build_sender_fullhost();
1696 }
1697
1698 /* Delay this until we have the full name, if it is looked up. */
1699
1700 set_process_info("handling incoming connection from %s",
1701 host_and_ident(FALSE));
1702
1703 /* Start up TLS if tls_on_connect is set. This is for supporting the legacy
1704 smtps port for use with older style SSL MTAs. */
1705
1706 #ifdef SUPPORT_TLS
817d9f57 1707 if (tls_in.on_connect && tls_server_start(tls_require_ciphers) != OK)
059ec3d9
PH
1708 return FALSE;
1709 #endif
1710
1711 /* Test for explicit connection rejection */
1712
1713 if (verify_check_host(&host_reject_connection) == OK)
1714 {
1715 log_write(L_connection_reject, LOG_MAIN|LOG_REJECT, "refused connection "
1716 "from %s (host_reject_connection)", host_and_ident(FALSE));
1717 smtp_printf("554 SMTP service not available\r\n");
1718 return FALSE;
1719 }
1720
afb3eaaf
PH
1721 /* Test with TCP Wrappers if so configured. There is a problem in that
1722 hosts_ctl() returns 0 (deny) under a number of system failure circumstances,
1723 such as disks dying. In these cases, it is desirable to reject with a 4xx
1724 error instead of a 5xx error. There isn't a "right" way to detect such
1725 problems. The following kludge is used: errno is zeroed before calling
1726 hosts_ctl(). If the result is "reject", a 5xx error is given only if the
1727 value of errno is 0 or ENOENT (which happens if /etc/hosts.{allow,deny} does
1728 not exist). */
059ec3d9
PH
1729
1730 #ifdef USE_TCP_WRAPPERS
afb3eaaf 1731 errno = 0;
5dc43717
JJ
1732 tcp_wrappers_name = expand_string(tcp_wrappers_daemon_name);
1733 if (tcp_wrappers_name == NULL)
1734 {
1735 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "Expansion of \"%s\" "
1736 "(tcp_wrappers_name) failed: %s", string_printing(tcp_wrappers_name),
1737 expand_string_message);
1738 }
1739 if (!hosts_ctl(tcp_wrappers_name,
059ec3d9
PH
1740 (sender_host_name == NULL)? STRING_UNKNOWN : CS sender_host_name,
1741 (sender_host_address == NULL)? STRING_UNKNOWN : CS sender_host_address,
1742 (sender_ident == NULL)? STRING_UNKNOWN : CS sender_ident))
1743 {
afb3eaaf
PH
1744 if (errno == 0 || errno == ENOENT)
1745 {
1746 HDEBUG(D_receive) debug_printf("tcp wrappers rejection\n");
1747 log_write(L_connection_reject,
1748 LOG_MAIN|LOG_REJECT, "refused connection from %s "
1749 "(tcp wrappers)", host_and_ident(FALSE));
1750 smtp_printf("554 SMTP service not available\r\n");
1751 }
1752 else
1753 {
1754 int save_errno = errno;
1755 HDEBUG(D_receive) debug_printf("tcp wrappers rejected with unexpected "
1756 "errno value %d\n", save_errno);
1757 log_write(L_connection_reject,
1758 LOG_MAIN|LOG_REJECT, "temporarily refused connection from %s "
1759 "(tcp wrappers errno=%d)", host_and_ident(FALSE), save_errno);
1760 smtp_printf("451 Temporary local problem - please try later\r\n");
1761 }
059ec3d9
PH
1762 return FALSE;
1763 }
1764 #endif
1765
b01dd148
PH
1766 /* Check for reserved slots. The value of smtp_accept_count has already been
1767 incremented to include this process. */
059ec3d9
PH
1768
1769 if (smtp_accept_max > 0 &&
b01dd148 1770 smtp_accept_count > smtp_accept_max - smtp_accept_reserve)
059ec3d9
PH
1771 {
1772 if ((rc = verify_check_host(&smtp_reserve_hosts)) != OK)
1773 {
1774 log_write(L_connection_reject,
1775 LOG_MAIN, "temporarily refused connection from %s: not in "
1776 "reserve list: connected=%d max=%d reserve=%d%s",
b01dd148 1777 host_and_ident(FALSE), smtp_accept_count - 1, smtp_accept_max,
059ec3d9
PH
1778 smtp_accept_reserve, (rc == DEFER)? " (lookup deferred)" : "");
1779 smtp_printf("421 %s: Too many concurrent SMTP connections; "
1780 "please try again later\r\n", smtp_active_hostname);
1781 return FALSE;
1782 }
1783 reserved_host = TRUE;
1784 }
1785
1786 /* If a load level above which only messages from reserved hosts are
1787 accepted is set, check the load. For incoming calls via the daemon, the
1788 check is done in the superior process if there are no reserved hosts, to
1789 save a fork. In all cases, the load average will already be available
1790 in a global variable at this point. */
1791
1792 if (smtp_load_reserve >= 0 &&
1793 load_average > smtp_load_reserve &&
1794 !reserved_host &&
1795 verify_check_host(&smtp_reserve_hosts) != OK)
1796 {
1797 log_write(L_connection_reject,
1798 LOG_MAIN, "temporarily refused connection from %s: not in "
1799 "reserve list and load average = %.2f", host_and_ident(FALSE),
1800 (double)load_average/1000.0);
1801 smtp_printf("421 %s: Too much load; please try again later\r\n",
1802 smtp_active_hostname);
1803 return FALSE;
1804 }
1805
1806 /* Determine whether unqualified senders or recipients are permitted
1807 for this host. Unfortunately, we have to do this every time, in order to
1808 set the flags so that they can be inspected when considering qualifying
1809 addresses in the headers. For a site that permits no qualification, this
1810 won't take long, however. */
1811
1812 allow_unqualified_sender =
1813 verify_check_host(&sender_unqualified_hosts) == OK;
1814
1815 allow_unqualified_recipient =
1816 verify_check_host(&recipient_unqualified_hosts) == OK;
1817
1818 /* Determine whether HELO/EHLO is required for this host. The requirement
1819 can be hard or soft. */
1820
1821 helo_required = verify_check_host(&helo_verify_hosts) == OK;
1822 if (!helo_required)
1823 helo_verify = verify_check_host(&helo_try_verify_hosts) == OK;
1824
1825 /* Determine whether this hosts is permitted to send syntactic junk
1826 after a HELO or EHLO command. */
1827
1828 helo_accept_junk = verify_check_host(&helo_accept_junk_hosts) == OK;
1829 }
1830
1831/* For batch SMTP input we are now done. */
1832
1833if (smtp_batched_input) return TRUE;
1834
1835/* Run the ACL if it exists */
1836
4e88a19f 1837user_msg = NULL;
059ec3d9
PH
1838if (acl_smtp_connect != NULL)
1839 {
1840 int rc;
64ffc24f 1841 rc = acl_check(ACL_WHERE_CONNECT, NULL, acl_smtp_connect, &user_msg,
059ec3d9
PH
1842 &log_msg);
1843 if (rc != OK)
1844 {
1845 (void)smtp_handle_acl_fail(ACL_WHERE_CONNECT, rc, user_msg, log_msg);
1846 return FALSE;
1847 }
1848 }
1849
1850/* Output the initial message for a two-way SMTP connection. It may contain
1851newlines, which then cause a multi-line response to be given. */
1852
4e88a19f
PH
1853code = US"220"; /* Default status code */
1854esc = US""; /* Default extended status code */
1855esclen = 0; /* Length of esc */
1856
1857if (user_msg == NULL)
1858 {
1859 s = expand_string(smtp_banner);
1860 if (s == NULL)
1861 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "Expansion of \"%s\" (smtp_banner) "
1862 "failed: %s", smtp_banner, expand_string_message);
1863 }
1864else
1865 {
1866 int codelen = 3;
1867 s = user_msg;
1868 smtp_message_code(&code, &codelen, &s, NULL);
d6a96edc 1869 if (codelen > 4)
4e88a19f
PH
1870 {
1871 esc = code + 4;
1872 esclen = codelen - 4;
1873 }
1874 }
059ec3d9
PH
1875
1876/* Remove any terminating newlines; might as well remove trailing space too */
1877
1878p = s + Ustrlen(s);
1879while (p > s && isspace(p[-1])) p--;
1880*p = 0;
1881
1882/* It seems that CC:Mail is braindead, and assumes that the greeting message
1883is all contained in a single IP packet. The original code wrote out the
1884greeting using several calls to fprint/fputc, and on busy servers this could
1885cause it to be split over more than one packet - which caused CC:Mail to fall
1886over when it got the second part of the greeting after sending its first
1887command. Sigh. To try to avoid this, build the complete greeting message
1888first, and output it in one fell swoop. This gives a better chance of it
1889ending up as a single packet. */
1890
1891ss = store_get(size);
1892ptr = 0;
1893
1894p = s;
1895do /* At least once, in case we have an empty string */
1896 {
1897 int len;
1898 uschar *linebreak = Ustrchr(p, '\n');
4e88a19f 1899 ss = string_cat(ss, &size, &ptr, code, 3);
059ec3d9
PH
1900 if (linebreak == NULL)
1901 {
1902 len = Ustrlen(p);
4e88a19f 1903 ss = string_cat(ss, &size, &ptr, US" ", 1);
059ec3d9
PH
1904 }
1905 else
1906 {
1907 len = linebreak - p;
4e88a19f 1908 ss = string_cat(ss, &size, &ptr, US"-", 1);
059ec3d9 1909 }
4e88a19f 1910 ss = string_cat(ss, &size, &ptr, esc, esclen);
059ec3d9
PH
1911 ss = string_cat(ss, &size, &ptr, p, len);
1912 ss = string_cat(ss, &size, &ptr, US"\r\n", 2);
1913 p += len;
1914 if (linebreak != NULL) p++;
1915 }
1916while (*p != 0);
1917
1918ss[ptr] = 0; /* string_cat leaves room for this */
1919
1920/* Before we write the banner, check that there is no input pending, unless
1921this synchronisation check is disabled. */
1922
a14e5636 1923if (!check_sync())
059ec3d9 1924 {
a14e5636
PH
1925 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP protocol "
1926 "synchronization error (input sent without waiting for greeting): "
1927 "rejected connection from %s input=\"%s\"", host_and_ident(TRUE),
1928 string_printing(smtp_inptr));
1929 smtp_printf("554 SMTP synchronization error\r\n");
1930 return FALSE;
059ec3d9
PH
1931 }
1932
1933/* Now output the banner */
1934
1935smtp_printf("%s", ss);
1936return TRUE;
1937}
1938
1939
1940
1941
1942
1943/*************************************************
1944* Handle SMTP syntax and protocol errors *
1945*************************************************/
1946
1947/* Write to the log for SMTP syntax errors in incoming commands, if configured
1948to do so. Then transmit the error response. The return value depends on the
1949number of syntax and protocol errors in this SMTP session.
1950
1951Arguments:
1952 type error type, given as a log flag bit
1953 code response code; <= 0 means don't send a response
1954 data data to reflect in the response (can be NULL)
1955 errmess the error message
1956
1957Returns: -1 limit of syntax/protocol errors NOT exceeded
1958 +1 limit of syntax/protocol errors IS exceeded
1959
1960These values fit in with the values of the "done" variable in the main
1961processing loop in smtp_setup_msg(). */
1962
1963static int
1964synprot_error(int type, int code, uschar *data, uschar *errmess)
1965{
1966int yield = -1;
1967
1968log_write(type, LOG_MAIN, "SMTP %s error in \"%s\" %s %s",
1969 (type == L_smtp_syntax_error)? "syntax" : "protocol",
3ee512ff 1970 string_printing(smtp_cmd_buffer), host_and_ident(TRUE), errmess);
059ec3d9
PH
1971
1972if (++synprot_error_count > smtp_max_synprot_errors)
1973 {
1974 yield = 1;
1975 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
1976 "syntax or protocol errors (last command was \"%s\")",
3ee512ff 1977 host_and_ident(FALSE), smtp_cmd_buffer);
059ec3d9
PH
1978 }
1979
1980if (code > 0)
1981 {
1982 smtp_printf("%d%c%s%s%s\r\n", code, (yield == 1)? '-' : ' ',
1983 (data == NULL)? US"" : data, (data == NULL)? US"" : US": ", errmess);
1984 if (yield == 1)
1985 smtp_printf("%d Too many syntax or protocol errors\r\n", code);
1986 }
1987
1988return yield;
1989}
1990
1991
1992
1993
1994/*************************************************
1995* Log incomplete transactions *
1996*************************************************/
1997
1998/* This function is called after a transaction has been aborted by RSET, QUIT,
1999connection drops or other errors. It logs the envelope information received
2000so far in order to preserve address verification attempts.
2001
2002Argument: string to indicate what aborted the transaction
2003Returns: nothing
2004*/
2005
2006static void
2007incomplete_transaction_log(uschar *what)
2008{
2009if (sender_address == NULL || /* No transaction in progress */
2010 (log_write_selector & L_smtp_incomplete_transaction) == 0 /* Not logging */
2011 ) return;
2012
2013/* Build list of recipients for logging */
2014
2015if (recipients_count > 0)
2016 {
2017 int i;
2018 raw_recipients = store_get(recipients_count * sizeof(uschar *));
2019 for (i = 0; i < recipients_count; i++)
2020 raw_recipients[i] = recipients_list[i].address;
2021 raw_recipients_count = recipients_count;
2022 }
2023
2024log_write(L_smtp_incomplete_transaction, LOG_MAIN|LOG_SENDER|LOG_RECIPIENTS,
2025 "%s incomplete transaction (%s)", host_and_ident(TRUE), what);
2026}
2027
2028
2029
2030
2031/*************************************************
2032* Send SMTP response, possibly multiline *
2033*************************************************/
2034
2035/* There are, it seems, broken clients out there that cannot handle multiline
2036responses. If no_multiline_responses is TRUE (it can be set from an ACL), we
2037output nothing for non-final calls, and only the first line for anything else.
2038
2039Arguments:
a5bd321b 2040 code SMTP code, may involve extended status codes
d6a96edc 2041 codelen length of smtp code; if > 4 there's an ESC
059ec3d9
PH
2042 final FALSE if the last line isn't the final line
2043 msg message text, possibly containing newlines
2044
2045Returns: nothing
2046*/
2047
2048void
a5bd321b 2049smtp_respond(uschar* code, int codelen, BOOL final, uschar *msg)
059ec3d9 2050{
a5bd321b
PH
2051int esclen = 0;
2052uschar *esc = US"";
2053
059ec3d9
PH
2054if (!final && no_multiline_responses) return;
2055
d6a96edc 2056if (codelen > 4)
a5bd321b
PH
2057 {
2058 esc = code + 4;
2059 esclen = codelen - 4;
2060 }
2061
2679d413
PH
2062/* If this is the first output for a (non-batch) RCPT command, see if all RCPTs
2063have had the same. Note: this code is also present in smtp_printf(). It would
2064be tidier to have it only in one place, but when it was added, it was easier to
2065do it that way, so as not to have to mess with the code for the RCPT command,
2066which sometimes uses smtp_printf() and sometimes smtp_respond(). */
2067
2068if (rcpt_in_progress)
2069 {
2070 if (rcpt_smtp_response == NULL)
2071 rcpt_smtp_response = string_copy(msg);
2072 else if (rcpt_smtp_response_same &&
2073 Ustrcmp(rcpt_smtp_response, msg) != 0)
2074 rcpt_smtp_response_same = FALSE;
2075 rcpt_in_progress = FALSE;
2076 }
2077
2078/* Not output the message, splitting it up into multiple lines if necessary. */
2079
059ec3d9
PH
2080for (;;)
2081 {
2082 uschar *nl = Ustrchr(msg, '\n');
2083 if (nl == NULL)
2084 {
a5bd321b 2085 smtp_printf("%.3s%c%.*s%s\r\n", code, final? ' ':'-', esclen, esc, msg);
059ec3d9
PH
2086 return;
2087 }
2088 else if (nl[1] == 0 || no_multiline_responses)
2089 {
a5bd321b
PH
2090 smtp_printf("%.3s%c%.*s%.*s\r\n", code, final? ' ':'-', esclen, esc,
2091 (int)(nl - msg), msg);
059ec3d9
PH
2092 return;
2093 }
2094 else
2095 {
a5bd321b 2096 smtp_printf("%.3s-%.*s%.*s\r\n", code, esclen, esc, (int)(nl - msg), msg);
059ec3d9
PH
2097 msg = nl + 1;
2098 while (isspace(*msg)) msg++;
2099 }
2100 }
2101}
2102
2103
2104
2105
2106/*************************************************
4e88a19f
PH
2107* Parse user SMTP message *
2108*************************************************/
2109
2110/* This function allows for user messages overriding the response code details
2111by providing a suitable response code string at the start of the message
2112user_msg. Check the message for starting with a response code and optionally an
2113extended status code. If found, check that the first digit is valid, and if so,
2114change the code pointer and length to use the replacement. An invalid code
2115causes a panic log; in this case, if the log messages is the same as the user
2116message, we must also adjust the value of the log message to show the code that
2117is actually going to be used (the original one).
2118
2119This function is global because it is called from receive.c as well as within
2120this module.
2121
d6a96edc
PH
2122Note that the code length returned includes the terminating whitespace
2123character, which is always included in the regex match.
2124
4e88a19f
PH
2125Arguments:
2126 code SMTP code, may involve extended status codes
d6a96edc 2127 codelen length of smtp code; if > 4 there's an ESC
4e88a19f
PH
2128 msg message text
2129 log_msg optional log message, to be adjusted with the new SMTP code
2130
2131Returns: nothing
2132*/
2133
2134void
2135smtp_message_code(uschar **code, int *codelen, uschar **msg, uschar **log_msg)
2136{
2137int n;
2138int ovector[3];
2139
2140if (msg == NULL || *msg == NULL) return;
2141
2142n = pcre_exec(regex_smtp_code, NULL, CS *msg, Ustrlen(*msg), 0,
2143 PCRE_EOPT, ovector, sizeof(ovector)/sizeof(int));
2144if (n < 0) return;
2145
2146if ((*msg)[0] != (*code)[0])
2147 {
2148 log_write(0, LOG_MAIN|LOG_PANIC, "configured error code starts with "
2149 "incorrect digit (expected %c) in \"%s\"", (*code)[0], *msg);
2150 if (log_msg != NULL && *log_msg == *msg)
2151 *log_msg = string_sprintf("%s %s", *code, *log_msg + ovector[1]);
2152 }
2153else
2154 {
2155 *code = *msg;
2156 *codelen = ovector[1]; /* Includes final space */
2157 }
2158*msg += ovector[1]; /* Chop the code off the message */
2159return;
2160}
2161
2162
2163
2164
2165/*************************************************
059ec3d9
PH
2166* Handle an ACL failure *
2167*************************************************/
2168
2169/* This function is called when acl_check() fails. As well as calls from within
2170this module, it is called from receive.c for an ACL after DATA. It sorts out
2171logging the incident, and sets up the error response. A message containing
2172newlines is turned into a multiline SMTP response, but for logging, only the
2173first line is used.
2174
a5bd321b
PH
2175There's a table of default permanent failure response codes to use in
2176globals.c, along with the table of names. VFRY is special. Despite RFC1123 it
2177defaults disabled in Exim. However, discussion in connection with RFC 821bis
2178(aka RFC 2821) has concluded that the response should be 252 in the disabled
2179state, because there are broken clients that try VRFY before RCPT. A 5xx
2180response should be given only when the address is positively known to be
2181undeliverable. Sigh. Also, for ETRN, 458 is given on refusal, and for AUTH,
2182503.
2183
2184From Exim 4.63, it is possible to override the response code details by
2185providing a suitable response code string at the start of the message provided
2186in user_msg. The code's first digit is checked for validity.
059ec3d9
PH
2187
2188Arguments:
2189 where where the ACL was called from
2190 rc the failure code
2191 user_msg a message that can be included in an SMTP response
2192 log_msg a message for logging
2193
2194Returns: 0 in most cases
2195 2 if the failure code was FAIL_DROP, in which case the
2196 SMTP connection should be dropped (this value fits with the
2197 "done" variable in smtp_setup_msg() below)
2198*/
2199
2200int
2201smtp_handle_acl_fail(int where, int rc, uschar *user_msg, uschar *log_msg)
2202{
059ec3d9 2203BOOL drop = rc == FAIL_DROP;
a5bd321b 2204int codelen = 3;
a5bd321b 2205uschar *smtp_code;
059ec3d9
PH
2206uschar *lognl;
2207uschar *sender_info = US"";
64ffc24f 2208uschar *what =
8523533c 2209#ifdef WITH_CONTENT_SCAN
64ffc24f 2210 (where == ACL_WHERE_MIME)? US"during MIME ACL checks" :
8e669ac1 2211#endif
64ffc24f
PH
2212 (where == ACL_WHERE_PREDATA)? US"DATA" :
2213 (where == ACL_WHERE_DATA)? US"after DATA" :
fd98a5c6
JH
2214#ifdef EXPERIMENTAL_PRDR
2215 (where == ACL_WHERE_PRDR)? US"after DATA PRDR" :
2216#endif
ca86f471 2217 (smtp_cmd_data == NULL)?
64ffc24f 2218 string_sprintf("%s in \"connect\" ACL", acl_wherenames[where]) :
ca86f471 2219 string_sprintf("%s %s", acl_wherenames[where], smtp_cmd_data);
059ec3d9
PH
2220
2221if (drop) rc = FAIL;
2222
4e88a19f 2223/* Set the default SMTP code, and allow a user message to change it. */
a5bd321b
PH
2224
2225smtp_code = (rc != FAIL)? US"451" : acl_wherecodes[where];
4e88a19f 2226smtp_message_code(&smtp_code, &codelen, &user_msg, &log_msg);
a5bd321b 2227
059ec3d9
PH
2228/* We used to have sender_address here; however, there was a bug that was not
2229updating sender_address after a rewrite during a verify. When this bug was
2230fixed, sender_address at this point became the rewritten address. I'm not sure
2231this is what should be logged, so I've changed to logging the unrewritten
2232address to retain backward compatibility. */
2233
8523533c 2234#ifndef WITH_CONTENT_SCAN
059ec3d9 2235if (where == ACL_WHERE_RCPT || where == ACL_WHERE_DATA)
8523533c
TK
2236#else
2237if (where == ACL_WHERE_RCPT || where == ACL_WHERE_DATA || where == ACL_WHERE_MIME)
2238#endif
059ec3d9 2239 {
b98bb9ac
PP
2240 sender_info = string_sprintf("F=<%s>%s%s%s%s ",
2241 sender_address_unrewritten ? sender_address_unrewritten : sender_address,
2242 sender_host_authenticated ? US" A=" : US"",
2243 sender_host_authenticated ? sender_host_authenticated : US"",
2244 sender_host_authenticated && authenticated_id ? US":" : US"",
2245 sender_host_authenticated && authenticated_id ? authenticated_id : US""
2246 );
059ec3d9
PH
2247 }
2248
2249/* If there's been a sender verification failure with a specific message, and
2250we have not sent a response about it yet, do so now, as a preliminary line for
278c6e6c
PH
2251failures, but not defers. However, always log it for defer, and log it for fail
2252unless the sender_verify_fail log selector has been turned off. */
059ec3d9
PH
2253
2254if (sender_verified_failed != NULL &&
2255 !testflag(sender_verified_failed, af_sverify_told))
2256 {
2679d413
PH
2257 BOOL save_rcpt_in_progress = rcpt_in_progress;
2258 rcpt_in_progress = FALSE; /* So as not to treat these as the error */
2259
059ec3d9
PH
2260 setflag(sender_verified_failed, af_sverify_told);
2261
278c6e6c
PH
2262 if (rc != FAIL || (log_extra_selector & LX_sender_verify_fail) != 0)
2263 log_write(0, LOG_MAIN|LOG_REJECT, "%s sender verify %s for <%s>%s",
2264 host_and_ident(TRUE),
2265 ((sender_verified_failed->special_action & 255) == DEFER)? "defer":"fail",
2266 sender_verified_failed->address,
2267 (sender_verified_failed->message == NULL)? US"" :
2268 string_sprintf(": %s", sender_verified_failed->message));
059ec3d9
PH
2269
2270 if (rc == FAIL && sender_verified_failed->user_message != NULL)
a5bd321b 2271 smtp_respond(smtp_code, codelen, FALSE, string_sprintf(
059ec3d9
PH
2272 testflag(sender_verified_failed, af_verify_pmfail)?
2273 "Postmaster verification failed while checking <%s>\n%s\n"
2274 "Several RFCs state that you are required to have a postmaster\n"
2275 "mailbox for each mail domain. This host does not accept mail\n"
2276 "from domains whose servers reject the postmaster address."
2277 :
2278 testflag(sender_verified_failed, af_verify_nsfail)?
2279 "Callback setup failed while verifying <%s>\n%s\n"
2280 "The initial connection, or a HELO or MAIL FROM:<> command was\n"
2281 "rejected. Refusing MAIL FROM:<> does not help fight spam, disregards\n"
2282 "RFC requirements, and stops you from receiving standard bounce\n"
2283 "messages. This host does not accept mail from domains whose servers\n"
2284 "refuse bounces."
2285 :
2286 "Verification failed for <%s>\n%s",
2287 sender_verified_failed->address,
2288 sender_verified_failed->user_message));
2679d413
PH
2289
2290 rcpt_in_progress = save_rcpt_in_progress;
059ec3d9
PH
2291 }
2292
2293/* Sort out text for logging */
2294
2295log_msg = (log_msg == NULL)? US"" : string_sprintf(": %s", log_msg);
2296lognl = Ustrchr(log_msg, '\n');
2297if (lognl != NULL) *lognl = 0;
2298
2299/* Send permanent failure response to the command, but the code used isn't
2300always a 5xx one - see comments at the start of this function. If the original
2301rc was FAIL_DROP we drop the connection and yield 2. */
2302
a5bd321b 2303if (rc == FAIL) smtp_respond(smtp_code, codelen, TRUE, (user_msg == NULL)?
059ec3d9
PH
2304 US"Administrative prohibition" : user_msg);
2305
2306/* Send temporary failure response to the command. Don't give any details,
2307unless acl_temp_details is set. This is TRUE for a callout defer, a "defer"
2308verb, and for a header verify when smtp_return_error_details is set.
2309
2310This conditional logic is all somewhat of a mess because of the odd
2311interactions between temp_details and return_error_details. One day it should
2312be re-implemented in a tidier fashion. */
2313
2314else
2315 {
2316 if (acl_temp_details && user_msg != NULL)
2317 {
2318 if (smtp_return_error_details &&
2319 sender_verified_failed != NULL &&
2320 sender_verified_failed->message != NULL)
2321 {
a5bd321b 2322 smtp_respond(smtp_code, codelen, FALSE, sender_verified_failed->message);
059ec3d9 2323 }
a5bd321b 2324 smtp_respond(smtp_code, codelen, TRUE, user_msg);
059ec3d9
PH
2325 }
2326 else
a5bd321b
PH
2327 smtp_respond(smtp_code, codelen, TRUE,
2328 US"Temporary local problem - please try later");
059ec3d9
PH
2329 }
2330
6ea85e9a
PH
2331/* Log the incident to the logs that are specified by log_reject_target
2332(default main, reject). This can be empty to suppress logging of rejections. If
2333the connection is not forcibly to be dropped, return 0. Otherwise, log why it
2334is closing if required and return 2. */
059ec3d9 2335
6ea85e9a
PH
2336if (log_reject_target != 0)
2337 log_write(0, log_reject_target, "%s %s%srejected %s%s",
2338 host_and_ident(TRUE),
2339 sender_info, (rc == FAIL)? US"" : US"temporarily ", what, log_msg);
059ec3d9
PH
2340
2341if (!drop) return 0;
2342
2343log_write(L_smtp_connection, LOG_MAIN, "%s closed by DROP in ACL",
2344 smtp_get_connection_info());
8f128379
PH
2345
2346/* Run the not-quit ACL, but without any custom messages. This should not be a
2347problem, because we get here only if some other ACL has issued "drop", and
2348in that case, *its* custom messages will have been used above. */
2349
2350smtp_notquit_exit(US"acl-drop", NULL, NULL);
059ec3d9
PH
2351return 2;
2352}
2353
2354
2355
2356
2357/*************************************************
8f128379
PH
2358* Handle SMTP exit when QUIT is not given *
2359*************************************************/
2360
2361/* This function provides a logging/statistics hook for when an SMTP connection
2362is dropped on the floor or the other end goes away. It's a global function
2363because it's called from receive.c as well as this module. As well as running
2364the NOTQUIT ACL, if there is one, this function also outputs a final SMTP
2365response, either with a custom message from the ACL, or using a default. There
2366is one case, however, when no message is output - after "drop". In that case,
2367the ACL that obeyed "drop" has already supplied the custom message, and NULL is
2368passed to this function.
2369
2370In case things go wrong while processing this function, causing an error that
2371may re-enter this funtion, there is a recursion check.
2372
2373Arguments:
2374 reason What $smtp_notquit_reason will be set to in the ACL;
2375 if NULL, the ACL is not run
2376 code The error code to return as part of the response
2377 defaultrespond The default message if there's no user_msg
2378
2379Returns: Nothing
2380*/
2381
2382void
2383smtp_notquit_exit(uschar *reason, uschar *code, uschar *defaultrespond, ...)
2384{
2385int rc;
2386uschar *user_msg = NULL;
2387uschar *log_msg = NULL;
2388
2389/* Check for recursive acll */
2390
2391if (smtp_exit_function_called)
2392 {
2393 log_write(0, LOG_PANIC, "smtp_notquit_exit() called more than once (%s)",
2394 reason);
2395 return;
2396 }
2397smtp_exit_function_called = TRUE;
2398
2399/* Call the not-QUIT ACL, if there is one, unless no reason is given. */
2400
2401if (acl_smtp_notquit != NULL && reason != NULL)
2402 {
2403 smtp_notquit_reason = reason;
2404 rc = acl_check(ACL_WHERE_NOTQUIT, NULL, acl_smtp_notquit, &user_msg,
2405 &log_msg);
2406 if (rc == ERROR)
2407 log_write(0, LOG_MAIN|LOG_PANIC, "ACL for not-QUIT returned ERROR: %s",
2408 log_msg);
2409 }
2410
2411/* Write an SMTP response if we are expected to give one. As the default
2412responses are all internal, they should always fit in the buffer, but code a
2413warning, just in case. Note that string_vformat() still leaves a complete
2414string, even if it is incomplete. */
2415
2416if (code != NULL && defaultrespond != NULL)
2417 {
2418 if (user_msg == NULL)
2419 {
2420 uschar buffer[128];
2421 va_list ap;
2422 va_start(ap, defaultrespond);
2423 if (!string_vformat(buffer, sizeof(buffer), CS defaultrespond, ap))
2424 log_write(0, LOG_MAIN|LOG_PANIC, "string too large in smtp_notquit_exit()");
2425 smtp_printf("%s %s\r\n", code, buffer);
2426 va_end(ap);
2427 }
2428 else
2429 smtp_respond(code, 3, TRUE, user_msg);
2430 mac_smtp_fflush();
2431 }
2432}
2433
2434
2435
2436
2437/*************************************************
d7b47fd0
PH
2438* Verify HELO argument *
2439*************************************************/
2440
2441/* This function is called if helo_verify_hosts or helo_try_verify_hosts is
2442matched. It is also called from ACL processing if verify = helo is used and
2443verification was not previously tried (i.e. helo_try_verify_hosts was not
2444matched). The result of its processing is to set helo_verified and
2445helo_verify_failed. These variables should both be FALSE for this function to
2446be called.
2447
2448Note that EHLO/HELO is legitimately allowed to quote an address literal. Allow
2449for IPv6 ::ffff: literals.
2450
2451Argument: none
2452Returns: TRUE if testing was completed;
2453 FALSE on a temporary failure
2454*/
2455
2456BOOL
2457smtp_verify_helo(void)
2458{
2459BOOL yield = TRUE;
2460
2461HDEBUG(D_receive) debug_printf("verifying EHLO/HELO argument \"%s\"\n",
2462 sender_helo_name);
2463
2464if (sender_helo_name == NULL)
2465 {
2466 HDEBUG(D_receive) debug_printf("no EHLO/HELO command was issued\n");
2467 }
2468
d1d5595c
PH
2469/* Deal with the case of -bs without an IP address */
2470
2471else if (sender_host_address == NULL)
2472 {
2473 HDEBUG(D_receive) debug_printf("no client IP address: assume success\n");
2474 helo_verified = TRUE;
2475 }
2476
2477/* Deal with the more common case when there is a sending IP address */
2478
d7b47fd0
PH
2479else if (sender_helo_name[0] == '[')
2480 {
2481 helo_verified = Ustrncmp(sender_helo_name+1, sender_host_address,
2482 Ustrlen(sender_host_address)) == 0;
2483
2484 #if HAVE_IPV6
2485 if (!helo_verified)
2486 {
2487 if (strncmpic(sender_host_address, US"::ffff:", 7) == 0)
2488 helo_verified = Ustrncmp(sender_helo_name + 1,
2489 sender_host_address + 7, Ustrlen(sender_host_address) - 7) == 0;
2490 }
2491 #endif
2492
2493 HDEBUG(D_receive)
2494 { if (helo_verified) debug_printf("matched host address\n"); }
2495 }
2496
2497/* Do a reverse lookup if one hasn't already given a positive or negative
2498response. If that fails, or the name doesn't match, try checking with a forward
2499lookup. */
2500
2501else
2502 {
2503 if (sender_host_name == NULL && !host_lookup_failed)
2504 yield = host_name_lookup() != DEFER;
2505
2506 /* If a host name is known, check it and all its aliases. */
2507
2508 if (sender_host_name != NULL)
2509 {
2510 helo_verified = strcmpic(sender_host_name, sender_helo_name) == 0;
2511
2512 if (helo_verified)
2513 {
2514 HDEBUG(D_receive) debug_printf("matched host name\n");
2515 }
2516 else
2517 {
2518 uschar **aliases = sender_host_aliases;
2519 while (*aliases != NULL)
2520 {
2521 helo_verified = strcmpic(*aliases++, sender_helo_name) == 0;
2522 if (helo_verified) break;
2523 }
2524 HDEBUG(D_receive)
2525 {
2526 if (helo_verified)
2527 debug_printf("matched alias %s\n", *(--aliases));
2528 }
2529 }
2530 }
2531
2532 /* Final attempt: try a forward lookup of the helo name */
2533
2534 if (!helo_verified)
2535 {
2536 int rc;
2537 host_item h;
2538 h.name = sender_helo_name;
2539 h.address = NULL;
2540 h.mx = MX_NONE;
2541 h.next = NULL;
2542 HDEBUG(D_receive) debug_printf("getting IP address for %s\n",
2543 sender_helo_name);
322050c2 2544 rc = host_find_byname(&h, NULL, 0, NULL, TRUE);
d7b47fd0
PH
2545 if (rc == HOST_FOUND || rc == HOST_FOUND_LOCAL)
2546 {
2547 host_item *hh = &h;
2548 while (hh != NULL)
2549 {
2550 if (Ustrcmp(hh->address, sender_host_address) == 0)
2551 {
2552 helo_verified = TRUE;
2553 HDEBUG(D_receive)
2554 debug_printf("IP address for %s matches calling address\n",
2555 sender_helo_name);
2556 break;
2557 }
2558 hh = hh->next;
2559 }
2560 }
2561 }
2562 }
2563
d1d5595c 2564if (!helo_verified) helo_verify_failed = TRUE; /* We've tried ... */
d7b47fd0
PH
2565return yield;
2566}
2567
2568
2569
2570
2571/*************************************************
4e88a19f
PH
2572* Send user response message *
2573*************************************************/
2574
2575/* This function is passed a default response code and a user message. It calls
2576smtp_message_code() to check and possibly modify the response code, and then
2577calls smtp_respond() to transmit the response. I put this into a function
2578just to avoid a lot of repetition.
2579
2580Arguments:
2581 code the response code
2582 user_msg the user message
2583
2584Returns: nothing
2585*/
2586
2587static void
2588smtp_user_msg(uschar *code, uschar *user_msg)
2589{
2590int len = 3;
2591smtp_message_code(&code, &len, &user_msg, NULL);
2592smtp_respond(code, len, TRUE, user_msg);
2593}
2594
2595
2596
2597
2598/*************************************************
059ec3d9
PH
2599* Initialize for SMTP incoming message *
2600*************************************************/
2601
2602/* This function conducts the initial dialogue at the start of an incoming SMTP
2603message, and builds a list of recipients. However, if the incoming message
2604is part of a batch (-bS option) a separate function is called since it would
2605be messy having tests splattered about all over this function. This function
2606therefore handles the case where interaction is occurring. The input and output
2607files are set up in smtp_in and smtp_out.
2608
2609The global recipients_list is set to point to a vector of recipient_item
2610blocks, whose number is given by recipients_count. This is extended by the
2611receive_add_recipient() function. The global variable sender_address is set to
2612the sender's address. The yield is +1 if a message has been successfully
2613started, 0 if a QUIT command was encountered or the connection was refused from
2614the particular host, or -1 if the connection was lost.
2615
2616Argument: none
2617
2618Returns: > 0 message successfully started (reached DATA)
2619 = 0 QUIT read or end of file reached or call refused
2620 < 0 lost connection
2621*/
2622
2623int
2624smtp_setup_msg(void)
2625{
2626int done = 0;
2627BOOL toomany = FALSE;
2628BOOL discarded = FALSE;
2629BOOL last_was_rej_mail = FALSE;
2630BOOL last_was_rcpt = FALSE;
2631void *reset_point = store_get(0);
2632
2633DEBUG(D_receive) debug_printf("smtp_setup_msg entered\n");
2634
2635/* Reset for start of new message. We allow one RSET not to be counted as a
2636nonmail command, for those MTAs that insist on sending it between every
2637message. Ditto for EHLO/HELO and for STARTTLS, to allow for going in and out of
2638TLS between messages (an Exim client may do this if it has messages queued up
2639for the host). Note: we do NOT reset AUTH at this point. */
2640
2641smtp_reset(reset_point);
2642message_ended = END_NOTSTARTED;
2643
2644cmd_list[CMD_LIST_RSET].is_mail_cmd = TRUE;
2645cmd_list[CMD_LIST_HELO].is_mail_cmd = TRUE;
2646cmd_list[CMD_LIST_EHLO].is_mail_cmd = TRUE;
2647#ifdef SUPPORT_TLS
2648cmd_list[CMD_LIST_STARTTLS].is_mail_cmd = TRUE;
2649#endif
2650
2651/* Set the local signal handler for SIGTERM - it tries to end off tidily */
2652
2653os_non_restarting_signal(SIGTERM, command_sigterm_handler);
2654
2655/* Batched SMTP is handled in a different function. */
2656
2657if (smtp_batched_input) return smtp_setup_batch_msg();
2658
2659/* Deal with SMTP commands. This loop is exited by setting done to a POSITIVE
2660value. The values are 2 larger than the required yield of the function. */
2661
2662while (done <= 0)
2663 {
2664 uschar **argv;
2665 uschar *etrn_command;
2666 uschar *etrn_serialize_key;
2667 uschar *errmess;
4e88a19f
PH
2668 uschar *log_msg, *smtp_code;
2669 uschar *user_msg = NULL;
059ec3d9
PH
2670 uschar *recipient = NULL;
2671 uschar *hello = NULL;
2672 uschar *set_id = NULL;
2673 uschar *s, *ss;
2674 BOOL was_rej_mail = FALSE;
2675 BOOL was_rcpt = FALSE;
2676 void (*oldsignal)(int);
2677 pid_t pid;
2678 int start, end, sender_domain, recipient_domain;
2679 int ptr, size, rc;
f78eb7c6 2680 int c, i;
059ec3d9
PH
2681 auth_instance *au;
2682
2683 switch(smtp_read_command(TRUE))
2684 {
2685 /* The AUTH command is not permitted to occur inside a transaction, and may
c46782ef
PH
2686 occur successfully only once per connection. Actually, that isn't quite
2687 true. When TLS is started, all previous information about a connection must
2688 be discarded, so a new AUTH is permitted at that time.
2689
2690 AUTH may only be used when it has been advertised. However, it seems that
2691 there are clients that send AUTH when it hasn't been advertised, some of
2692 them even doing this after HELO. And there are MTAs that accept this. Sigh.
2693 So there's a get-out that allows this to happen.
059ec3d9
PH
2694
2695 AUTH is initially labelled as a "nonmail command" so that one occurrence
2696 doesn't get counted. We change the label here so that multiple failing
2697 AUTHS will eventually hit the nonmail threshold. */
2698
2699 case AUTH_CMD:
b4ed4da0 2700 HAD(SCH_AUTH);
059ec3d9
PH
2701 authentication_failed = TRUE;
2702 cmd_list[CMD_LIST_AUTH].is_mail_cmd = FALSE;
2703
c46782ef 2704 if (!auth_advertised && !allow_auth_unadvertised)
059ec3d9
PH
2705 {
2706 done = synprot_error(L_smtp_protocol_error, 503, NULL,
2707 US"AUTH command used when not advertised");
2708 break;
2709 }
2710 if (sender_host_authenticated != NULL)
2711 {
2712 done = synprot_error(L_smtp_protocol_error, 503, NULL,
2713 US"already authenticated");
2714 break;
2715 }
2716 if (sender_address != NULL)
2717 {
2718 done = synprot_error(L_smtp_protocol_error, 503, NULL,
2719 US"not permitted in mail transaction");
2720 break;
2721 }
2722
2723 /* Check the ACL */
2724
2725 if (acl_smtp_auth != NULL)
2726 {
64ffc24f 2727 rc = acl_check(ACL_WHERE_AUTH, NULL, acl_smtp_auth, &user_msg, &log_msg);
059ec3d9
PH
2728 if (rc != OK)
2729 {
2730 done = smtp_handle_acl_fail(ACL_WHERE_AUTH, rc, user_msg, log_msg);
2731 break;
2732 }
2733 }
2734
2735 /* Find the name of the requested authentication mechanism. */
2736
ca86f471
PH
2737 s = smtp_cmd_data;
2738 while ((c = *smtp_cmd_data) != 0 && !isspace(c))
059ec3d9
PH
2739 {
2740 if (!isalnum(c) && c != '-' && c != '_')
2741 {
2742 done = synprot_error(L_smtp_syntax_error, 501, NULL,
2743 US"invalid character in authentication mechanism name");
2744 goto COMMAND_LOOP;
2745 }
ca86f471 2746 smtp_cmd_data++;
059ec3d9
PH
2747 }
2748
2749 /* If not at the end of the line, we must be at white space. Terminate the
2750 name and move the pointer on to any data that may be present. */
2751
ca86f471 2752 if (*smtp_cmd_data != 0)
059ec3d9 2753 {
ca86f471
PH
2754 *smtp_cmd_data++ = 0;
2755 while (isspace(*smtp_cmd_data)) smtp_cmd_data++;
059ec3d9
PH
2756 }
2757
2758 /* Search for an authentication mechanism which is configured for use
c46782ef
PH
2759 as a server and which has been advertised (unless, sigh, allow_auth_
2760 unadvertised is set). */
059ec3d9
PH
2761
2762 for (au = auths; au != NULL; au = au->next)
2763 {
2764 if (strcmpic(s, au->public_name) == 0 && au->server &&
c46782ef 2765 (au->advertised || allow_auth_unadvertised)) break;
059ec3d9
PH
2766 }
2767
2768 if (au == NULL)
2769 {
2770 done = synprot_error(L_smtp_protocol_error, 504, NULL,
2771 string_sprintf("%s authentication mechanism not supported", s));
2772 break;
2773 }
2774
f78eb7c6
PH
2775 /* Run the checking code, passing the remainder of the command line as
2776 data. Initials the $auth<n> variables as empty. Initialize $0 empty and set
2777 it as the only set numerical variable. The authenticator may set $auth<n>
2778 and also set other numeric variables. The $auth<n> variables are preferred
2779 nowadays; the numerical variables remain for backwards compatibility.
059ec3d9 2780
f78eb7c6
PH
2781 Afterwards, have a go at expanding the set_id string, even if
2782 authentication failed - for bad passwords it can be useful to log the
2783 userid. On success, require set_id to expand and exist, and put it in
2784 authenticated_id. Save this in permanent store, as the working store gets
2785 reset at HELO, RSET, etc. */
2786
2787 for (i = 0; i < AUTH_VARS; i++) auth_vars[i] = NULL;
059ec3d9
PH
2788 expand_nmax = 0;
2789 expand_nlength[0] = 0; /* $0 contains nothing */
2790
ca86f471 2791 c = (au->info->servercode)(au, smtp_cmd_data);
059ec3d9
PH
2792 if (au->set_id != NULL) set_id = expand_string(au->set_id);
2793 expand_nmax = -1; /* Reset numeric variables */
f78eb7c6 2794 for (i = 0; i < AUTH_VARS; i++) auth_vars[i] = NULL; /* Reset $auth<n> */
059ec3d9 2795
0612b098
PH
2796 /* The value of authenticated_id is stored in the spool file and printed in
2797 log lines. It must not contain binary zeros or newline characters. In
2798 normal use, it never will, but when playing around or testing, this error
2799 can (did) happen. To guard against this, ensure that the id contains only
2800 printing characters. */
2801
2802 if (set_id != NULL) set_id = string_printing(set_id);
2803
059ec3d9
PH
2804 /* For the non-OK cases, set up additional logging data if set_id
2805 is not empty. */
2806
2807 if (c != OK)
2808 {
2809 if (set_id != NULL && *set_id != 0)
2810 set_id = string_sprintf(" (set_id=%s)", set_id);
2811 else set_id = US"";
2812 }
2813
2814 /* Switch on the result */
2815
2816 switch(c)
2817 {
2818 case OK:
2819 if (au->set_id == NULL || set_id != NULL) /* Complete success */
2820 {
2821 if (set_id != NULL) authenticated_id = string_copy_malloc(set_id);
2822 sender_host_authenticated = au->name;
2823 authentication_failed = FALSE;
2d07a215 2824 authenticated_fail_id = NULL; /* Impossible to already be set? */
059ec3d9 2825 received_protocol =
817d9f57 2826 protocols[pextend + pauthed + ((tls_in.active >= 0)? pcrpted:0)] +
059ec3d9
PH
2827 ((sender_host_address != NULL)? pnlocal : 0);
2828 s = ss = US"235 Authentication succeeded";
2829 authenticated_by = au;
2830 break;
2831 }
2832
2833 /* Authentication succeeded, but we failed to expand the set_id string.
2834 Treat this as a temporary error. */
2835
2836 auth_defer_msg = expand_string_message;
2837 /* Fall through */
2838
2839 case DEFER:
2d07a215 2840 if (set_id != NULL) authenticated_fail_id = string_copy_malloc(set_id);
059ec3d9
PH
2841 s = string_sprintf("435 Unable to authenticate at present%s",
2842 auth_defer_user_msg);
2843 ss = string_sprintf("435 Unable to authenticate at present%s: %s",
2844 set_id, auth_defer_msg);
2845 break;
2846
2847 case BAD64:
2848 s = ss = US"501 Invalid base64 data";
2849 break;
2850
2851 case CANCELLED:
2852 s = ss = US"501 Authentication cancelled";
2853 break;
2854
2855 case UNEXPECTED:
2856 s = ss = US"553 Initial data not expected";
2857 break;
2858
2859 case FAIL:
2d07a215 2860 if (set_id != NULL) authenticated_fail_id = string_copy_malloc(set_id);
059ec3d9
PH
2861 s = US"535 Incorrect authentication data";
2862 ss = string_sprintf("535 Incorrect authentication data%s", set_id);
2863 break;
2864
2865 default:
2d07a215 2866 if (set_id != NULL) authenticated_fail_id = string_copy_malloc(set_id);
059ec3d9
PH
2867 s = US"435 Internal error";
2868 ss = string_sprintf("435 Internal error%s: return %d from authentication "
2869 "check", set_id, c);
2870 break;
2871 }
2872
2873 smtp_printf("%s\r\n", s);
2874 if (c != OK)
2875 log_write(0, LOG_MAIN|LOG_REJECT, "%s authenticator failed for %s: %s",
2876 au->name, host_and_ident(FALSE), ss);
2877
2878 break; /* AUTH_CMD */
2879
2880 /* The HELO/EHLO commands are permitted to appear in the middle of a
2881 session as well as at the beginning. They have the effect of a reset in
2882 addition to their other functions. Their absence at the start cannot be
2883 taken to be an error.
2884
2885 RFC 2821 says:
2886
2887 If the EHLO command is not acceptable to the SMTP server, 501, 500,
2888 or 502 failure replies MUST be returned as appropriate. The SMTP
2889 server MUST stay in the same state after transmitting these replies
2890 that it was in before the EHLO was received.
2891
2892 Therefore, we do not do the reset until after checking the command for
2893 acceptability. This change was made for Exim release 4.11. Previously
2894 it did the reset first. */
2895
2896 case HELO_CMD:
b4ed4da0 2897 HAD(SCH_HELO);
059ec3d9
PH
2898 hello = US"HELO";
2899 esmtp = FALSE;
2900 goto HELO_EHLO;
2901
2902 case EHLO_CMD:
b4ed4da0 2903 HAD(SCH_EHLO);
059ec3d9
PH
2904 hello = US"EHLO";
2905 esmtp = TRUE;
2906
2907 HELO_EHLO: /* Common code for HELO and EHLO */
2908 cmd_list[CMD_LIST_HELO].is_mail_cmd = FALSE;
2909 cmd_list[CMD_LIST_EHLO].is_mail_cmd = FALSE;
2910
2911 /* Reject the HELO if its argument was invalid or non-existent. A
2912 successful check causes the argument to be saved in malloc store. */
2913
ca86f471 2914 if (!check_helo(smtp_cmd_data))
059ec3d9
PH
2915 {
2916 smtp_printf("501 Syntactically invalid %s argument(s)\r\n", hello);
2917
2918 log_write(0, LOG_MAIN|LOG_REJECT, "rejected %s from %s: syntactically "
2919 "invalid argument(s): %s", hello, host_and_ident(FALSE),
3ee512ff
PH
2920 (*smtp_cmd_argument == 0)? US"(no argument given)" :
2921 string_printing(smtp_cmd_argument));
059ec3d9
PH
2922
2923 if (++synprot_error_count > smtp_max_synprot_errors)
2924 {
2925 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
2926 "syntax or protocol errors (last command was \"%s\")",
3ee512ff 2927 host_and_ident(FALSE), smtp_cmd_buffer);
059ec3d9
PH
2928 done = 1;
2929 }
2930
2931 break;
2932 }
2933
2934 /* If sender_host_unknown is true, we have got here via the -bs interface,
2935 not called from inetd. Otherwise, we are running an IP connection and the
2936 host address will be set. If the helo name is the primary name of this
2937 host and we haven't done a reverse lookup, force one now. If helo_required
2938 is set, ensure that the HELO name matches the actual host. If helo_verify
2939 is set, do the same check, but softly. */
2940
2941 if (!sender_host_unknown)
2942 {
2943 BOOL old_helo_verified = helo_verified;
ca86f471 2944 uschar *p = smtp_cmd_data;
059ec3d9
PH
2945
2946 while (*p != 0 && !isspace(*p)) { *p = tolower(*p); p++; }
2947 *p = 0;
2948
2949 /* Force a reverse lookup if HELO quoted something in helo_lookup_domains
2950 because otherwise the log can be confusing. */
2951
2952 if (sender_host_name == NULL &&
2953 (deliver_domain = sender_helo_name, /* set $domain */
2954 match_isinlist(sender_helo_name, &helo_lookup_domains, 0,
2955 &domainlist_anchor, NULL, MCL_DOMAIN, TRUE, NULL)) == OK)
2956 (void)host_name_lookup();
2957
2958 /* Rebuild the fullhost info to include the HELO name (and the real name
2959 if it was looked up.) */
2960
2961 host_build_sender_fullhost(); /* Rebuild */
2962 set_process_info("handling%s incoming connection from %s",
817d9f57 2963 (tls_in.active >= 0)? " TLS" : "", host_and_ident(FALSE));
059ec3d9
PH
2964
2965 /* Verify if configured. This doesn't give much security, but it does
d7b47fd0
PH
2966 make some people happy to be able to do it. If helo_required is set,
2967 (host matches helo_verify_hosts) failure forces rejection. If helo_verify
2968 is set (host matches helo_try_verify_hosts), it does not. This is perhaps
2969 now obsolescent, since the verification can now be requested selectively
2970 at ACL time. */
059ec3d9 2971
d7b47fd0 2972 helo_verified = helo_verify_failed = FALSE;
059ec3d9
PH
2973 if (helo_required || helo_verify)
2974 {
d7b47fd0 2975 BOOL tempfail = !smtp_verify_helo();
059ec3d9
PH
2976 if (!helo_verified)
2977 {
2978 if (helo_required)
2979 {
2980 smtp_printf("%d %s argument does not match calling host\r\n",
2981 tempfail? 451 : 550, hello);
2982 log_write(0, LOG_MAIN|LOG_REJECT, "%srejected \"%s %s\" from %s",
2983 tempfail? "temporarily " : "",
2984 hello, sender_helo_name, host_and_ident(FALSE));
2985 helo_verified = old_helo_verified;
2986 break; /* End of HELO/EHLO processing */
2987 }
2988 HDEBUG(D_all) debug_printf("%s verification failed but host is in "
2989 "helo_try_verify_hosts\n", hello);
2990 }
2991 }
2992 }
2993
8523533c
TK
2994#ifdef EXPERIMENTAL_SPF
2995 /* set up SPF context */
2996 spf_init(sender_helo_name, sender_host_address);
2997#endif
2998
a14e5636
PH
2999 /* Apply an ACL check if one is defined; afterwards, recheck
3000 synchronization in case the client started sending in a delay. */
059ec3d9
PH
3001
3002 if (acl_smtp_helo != NULL)
3003 {
64ffc24f 3004 rc = acl_check(ACL_WHERE_HELO, NULL, acl_smtp_helo, &user_msg, &log_msg);
059ec3d9
PH
3005 if (rc != OK)
3006 {
3007 done = smtp_handle_acl_fail(ACL_WHERE_HELO, rc, user_msg, log_msg);
3008 sender_helo_name = NULL;
3009 host_build_sender_fullhost(); /* Rebuild */
3010 break;
3011 }
a14e5636 3012 else if (!check_sync()) goto SYNC_FAILURE;
059ec3d9
PH
3013 }
3014
4e88a19f
PH
3015 /* Generate an OK reply. The default string includes the ident if present,
3016 and also the IP address if present. Reflecting back the ident is intended
3017 as a deterrent to mail forgers. For maximum efficiency, and also because
3018 some broken systems expect each response to be in a single packet, arrange
3019 that the entire reply is sent in one write(). */
059ec3d9
PH
3020
3021 auth_advertised = FALSE;
3022 pipelining_advertised = FALSE;
3023 #ifdef SUPPORT_TLS
3024 tls_advertised = FALSE;
3025 #endif
3026
d6a96edc 3027 smtp_code = US"250 "; /* Default response code plus space*/
4e88a19f
PH
3028 if (user_msg == NULL)
3029 {
3030 s = string_sprintf("%.3s %s Hello %s%s%s",
3031 smtp_code,
3032 smtp_active_hostname,
3033 (sender_ident == NULL)? US"" : sender_ident,
3034 (sender_ident == NULL)? US"" : US" at ",
3035 (sender_host_name == NULL)? sender_helo_name : sender_host_name);
3036
3037 ptr = Ustrlen(s);
3038 size = ptr + 1;
059ec3d9 3039
4e88a19f
PH
3040 if (sender_host_address != NULL)
3041 {
3042 s = string_cat(s, &size, &ptr, US" [", 2);
3043 s = string_cat(s, &size, &ptr, sender_host_address,
3044 Ustrlen(sender_host_address));
3045 s = string_cat(s, &size, &ptr, US"]", 1);
3046 }
3047 }
3048
d6a96edc
PH
3049 /* A user-supplied EHLO greeting may not contain more than one line. Note
3050 that the code returned by smtp_message_code() includes the terminating
3051 whitespace character. */
059ec3d9 3052
4e88a19f 3053 else
059ec3d9 3054 {
4e88a19f 3055 char *ss;
d6a96edc 3056 int codelen = 4;
4e88a19f 3057 smtp_message_code(&smtp_code, &codelen, &user_msg, NULL);
d6a96edc 3058 s = string_sprintf("%.*s%s", codelen, smtp_code, user_msg);
4e88a19f
PH
3059 if ((ss = strpbrk(CS s, "\r\n")) != NULL)
3060 {
3061 log_write(0, LOG_MAIN|LOG_PANIC, "EHLO/HELO response must not contain "
3062 "newlines: message truncated: %s", string_printing(s));
3063 *ss = 0;
3064 }
3065 ptr = Ustrlen(s);
3066 size = ptr + 1;
059ec3d9
PH
3067 }
3068
3069 s = string_cat(s, &size, &ptr, US"\r\n", 2);
3070
3071 /* If we received EHLO, we must create a multiline response which includes
3072 the functions supported. */
3073
3074 if (esmtp)
3075 {
3076 s[3] = '-';
3077
3078 /* I'm not entirely happy with this, as an MTA is supposed to check
3079 that it has enough room to accept a message of maximum size before
3080 it sends this. However, there seems little point in not sending it.
3081 The actual size check happens later at MAIL FROM time. By postponing it
3082 till then, VRFY and EXPN can be used after EHLO when space is short. */
3083
3084 if (thismessage_size_limit > 0)
3085 {
4e88a19f
PH
3086 sprintf(CS big_buffer, "%.3s-SIZE %d\r\n", smtp_code,
3087 thismessage_size_limit);
059ec3d9
PH
3088 s = string_cat(s, &size, &ptr, big_buffer, Ustrlen(big_buffer));
3089 }
3090 else
3091 {
4e88a19f
PH
3092 s = string_cat(s, &size, &ptr, smtp_code, 3);
3093 s = string_cat(s, &size, &ptr, US"-SIZE\r\n", 7);
059ec3d9
PH
3094 }
3095
3096 /* Exim does not do protocol conversion or data conversion. It is 8-bit
3097 clean; if it has an 8-bit character in its hand, it just sends it. It
3098 cannot therefore specify 8BITMIME and remain consistent with the RFCs.
3099 However, some users want this option simply in order to stop MUAs
3100 mangling messages that contain top-bit-set characters. It is therefore
3101 provided as an option. */
3102
3103 if (accept_8bitmime)
4e88a19f
PH
3104 {
3105 s = string_cat(s, &size, &ptr, smtp_code, 3);
3106 s = string_cat(s, &size, &ptr, US"-8BITMIME\r\n", 11);
3107 }
059ec3d9
PH
3108
3109 /* Advertise ETRN if there's an ACL checking whether a host is
3110 permitted to issue it; a check is made when any host actually tries. */
3111
3112 if (acl_smtp_etrn != NULL)
3113 {
4e88a19f
PH
3114 s = string_cat(s, &size, &ptr, smtp_code, 3);
3115 s = string_cat(s, &size, &ptr, US"-ETRN\r\n", 7);
059ec3d9
PH
3116 }
3117
3118 /* Advertise EXPN if there's an ACL checking whether a host is
3119 permitted to issue it; a check is made when any host actually tries. */
3120
3121 if (acl_smtp_expn != NULL)
3122 {
4e88a19f
PH
3123 s = string_cat(s, &size, &ptr, smtp_code, 3);
3124 s = string_cat(s, &size, &ptr, US"-EXPN\r\n", 7);
059ec3d9
PH
3125 }
3126
3127 /* Exim is quite happy with pipelining, so let the other end know that
3128 it is safe to use it, unless advertising is disabled. */
3129
cf8b11a5
PH
3130 if (pipelining_enable &&
3131 verify_check_host(&pipelining_advertise_hosts) == OK)
059ec3d9 3132 {
4e88a19f
PH
3133 s = string_cat(s, &size, &ptr, smtp_code, 3);
3134 s = string_cat(s, &size, &ptr, US"-PIPELINING\r\n", 13);
059ec3d9
PH
3135 sync_cmd_limit = NON_SYNC_CMD_PIPELINING;
3136 pipelining_advertised = TRUE;
3137 }
3138
fd98a5c6 3139
059ec3d9
PH
3140 /* If any server authentication mechanisms are configured, advertise
3141 them if the current host is in auth_advertise_hosts. The problem with
3142 advertising always is that some clients then require users to
3143 authenticate (and aren't configurable otherwise) even though it may not
3144 be necessary (e.g. if the host is in host_accept_relay).
3145
3146 RFC 2222 states that SASL mechanism names contain only upper case
3147 letters, so output the names in upper case, though we actually recognize
3148 them in either case in the AUTH command. */
3149
3150 if (auths != NULL)
3151 {
3152 if (verify_check_host(&auth_advertise_hosts) == OK)
3153 {
3154 auth_instance *au;
3155 BOOL first = TRUE;
3156 for (au = auths; au != NULL; au = au->next)
3157 {
3158 if (au->server && (au->advertise_condition == NULL ||
3159 expand_check_condition(au->advertise_condition, au->name,
3160 US"authenticator")))
3161 {
3162 int saveptr;
3163 if (first)
3164 {
4e88a19f
PH
3165 s = string_cat(s, &size, &ptr, smtp_code, 3);
3166 s = string_cat(s, &size, &ptr, US"-AUTH", 5);
059ec3d9
PH
3167 first = FALSE;
3168 auth_advertised = TRUE;
3169 }
3170 saveptr = ptr;
3171 s = string_cat(s, &size, &ptr, US" ", 1);
3172 s = string_cat(s, &size, &ptr, au->public_name,
3173 Ustrlen(au->public_name));
3174 while (++saveptr < ptr) s[saveptr] = toupper(s[saveptr]);
3175 au->advertised = TRUE;
3176 }
3177 else au->advertised = FALSE;
3178 }
3179 if (!first) s = string_cat(s, &size, &ptr, US"\r\n", 2);
3180 }
3181 }
3182
3183 /* Advertise TLS (Transport Level Security) aka SSL (Secure Socket Layer)
3184 if it has been included in the binary, and the host matches
3185 tls_advertise_hosts. We must *not* advertise if we are already in a
3186 secure connection. */
3187
3188 #ifdef SUPPORT_TLS
817d9f57 3189 if (tls_in.active < 0 &&
059ec3d9
PH
3190 verify_check_host(&tls_advertise_hosts) != FAIL)
3191 {
4e88a19f
PH
3192 s = string_cat(s, &size, &ptr, smtp_code, 3);
3193 s = string_cat(s, &size, &ptr, US"-STARTTLS\r\n", 11);
059ec3d9
PH
3194 tls_advertised = TRUE;
3195 }
3196 #endif
3197
fd98a5c6
JH
3198 #ifdef EXPERIMENTAL_PRDR
3199 /* Per Recipient Data Response, draft by Eric A. Hall extending RFC */
3200 if (prdr_enable) {
3201 s = string_cat(s, &size, &ptr, smtp_code, 3);
3202 s = string_cat(s, &size, &ptr, US"-PRDR\r\n", 7);
3203 }
3204 #endif
3205
059ec3d9
PH
3206 /* Finish off the multiline reply with one that is always available. */
3207
4e88a19f
PH
3208 s = string_cat(s, &size, &ptr, smtp_code, 3);
3209 s = string_cat(s, &size, &ptr, US" HELP\r\n", 7);
059ec3d9
PH
3210 }
3211
3212 /* Terminate the string (for debug), write it, and note that HELO/EHLO
3213 has been seen. */
3214
3215 s[ptr] = 0;
3216
3217 #ifdef SUPPORT_TLS
817d9f57 3218 if (tls_in.active >= 0) (void)tls_write(TRUE, s, ptr); else
059ec3d9
PH
3219 #endif
3220
1ac6b2e7
JH
3221 {
3222 int i = fwrite(s, 1, ptr, smtp_out); i = i; /* compiler quietening */
3223 }
898d150f
PH
3224 DEBUG(D_receive)
3225 {
3226 uschar *cr;
3227 while ((cr = Ustrchr(s, '\r')) != NULL) /* lose CRs */
3228 memmove(cr, cr + 1, (ptr--) - (cr - s));
3229 debug_printf("SMTP>> %s", s);
3230 }
059ec3d9 3231 helo_seen = TRUE;
4e88a19f
PH
3232
3233 /* Reset the protocol and the state, abandoning any previous message. */
3234
3235 received_protocol = (esmtp?
3236 protocols[pextend +
3237 ((sender_host_authenticated != NULL)? pauthed : 0) +
817d9f57 3238 ((tls_in.active >= 0)? pcrpted : 0)]
4e88a19f 3239 :
817d9f57 3240 protocols[pnormal + ((tls_in.active >= 0)? pcrpted : 0)])
4e88a19f
PH
3241 +
3242 ((sender_host_address != NULL)? pnlocal : 0);
3243
3244 smtp_reset(reset_point);
3245 toomany = FALSE;
059ec3d9
PH
3246 break; /* HELO/EHLO */
3247
3248
3249 /* The MAIL command requires an address as an operand. All we do
3250 here is to parse it for syntactic correctness. The form "<>" is
3251 a special case which converts into an empty string. The start/end
3252 pointers in the original are not used further for this address, as
3253 it is the canonical extracted address which is all that is kept. */
3254
3255 case MAIL_CMD:
b4ed4da0 3256 HAD(SCH_MAIL);
059ec3d9
PH
3257 smtp_mailcmd_count++; /* Count for limit and ratelimit */
3258 was_rej_mail = TRUE; /* Reset if accepted */
d27f98fe 3259 env_mail_type_t * mail_args; /* Sanity check & validate args */
059ec3d9
PH
3260
3261 if (helo_required && !helo_seen)
3262 {
3263 smtp_printf("503 HELO or EHLO required\r\n");
3264 log_write(0, LOG_MAIN|LOG_REJECT, "rejected MAIL from %s: no "
3265 "HELO/EHLO given", host_and_ident(FALSE));
3266 break;
3267 }
3268
3269 if (sender_address != NULL)
3270 {
3271 done = synprot_error(L_smtp_protocol_error, 503, NULL,
3272 US"sender already given");
3273 break;
3274 }
3275
ca86f471 3276 if (smtp_cmd_data[0] == 0)
059ec3d9
PH
3277 {
3278 done = synprot_error(L_smtp_protocol_error, 501, NULL,
3279 US"MAIL must have an address operand");
3280 break;
3281 }
3282
3283 /* Check to see if the limit for messages per connection would be
3284 exceeded by accepting further messages. */
3285
3286 if (smtp_accept_max_per_connection > 0 &&
3287 smtp_mailcmd_count > smtp_accept_max_per_connection)
3288 {
3289 smtp_printf("421 too many messages in this connection\r\n");
3290 log_write(0, LOG_MAIN|LOG_REJECT, "rejected MAIL command %s: too many "
3291 "messages in one connection", host_and_ident(TRUE));
3292 break;
3293 }
3294
3295 /* Reset for start of message - even if this is going to fail, we
3296 obviously need to throw away any previous data. */
3297
3298 smtp_reset(reset_point);
3299 toomany = FALSE;
3300 sender_data = recipient_data = NULL;
3301
3302 /* Loop, checking for ESMTP additions to the MAIL FROM command. */
3303
3304 if (esmtp) for(;;)
3305 {
3306 uschar *name, *value, *end;
3307 unsigned long int size;
d27f98fe 3308 BOOL arg_error = FALSE;
059ec3d9
PH
3309
3310 if (!extract_option(&name, &value)) break;
3311
d27f98fe
TL
3312 for (mail_args = env_mail_type_list;
3313 (char *)mail_args < (char *)env_mail_type_list + sizeof(env_mail_type_list);
3314 mail_args++
3315 )
059ec3d9 3316 {
d27f98fe
TL
3317 if (strcmpic(name, mail_args->name) == 0)
3318 break;
059ec3d9 3319 }
d27f98fe
TL
3320 if (mail_args->need_value && strcmpic(value, US"") == 0)
3321 break;
059ec3d9 3322
d27f98fe 3323 switch(mail_args->value)
059ec3d9 3324 {
d27f98fe
TL
3325 /* Handle SIZE= by reading the value. We don't do the check till later,
3326 in order to be able to log the sender address on failure. */
3327 case ENV_MAIL_OPT_SIZE:
d27f98fe 3328 if (((size = Ustrtoul(value, &end, 10)), *end == 0))
059ec3d9 3329 {
d27f98fe
TL
3330 if ((size == ULONG_MAX && errno == ERANGE) || size > INT_MAX)
3331 size = INT_MAX;
3332 message_size = (int)size;
059ec3d9
PH
3333 }
3334 else
d27f98fe
TL
3335 arg_error = TRUE;
3336 break;
059ec3d9 3337
d27f98fe
TL
3338 /* If this session was initiated with EHLO and accept_8bitmime is set,
3339 Exim will have indicated that it supports the BODY=8BITMIME option. In
3340 fact, it does not support this according to the RFCs, in that it does not
3341 take any special action for forwarding messages containing 8-bit
3342 characters. That is why accept_8bitmime is not the default setting, but
3343 some sites want the action that is provided. We recognize both "8BITMIME"
3344 and "7BIT" as body types, but take no action. */
3345 case ENV_MAIL_OPT_BODY:
3c0a92dc
JH
3346 if (accept_8bitmime) {
3347 if (strcmpic(value, US"8BITMIME") == 0) {
3348 body_8bitmime = 8;
3349 } else if (strcmpic(value, US"7BIT") == 0) {
3350 body_8bitmime = 7;
3351 } else {
3352 body_8bitmime = 0;
3353 done = synprot_error(L_smtp_syntax_error, 501, NULL,
3354 US"invalid data for BODY");
3355 goto COMMAND_LOOP;
3356 }
3357 DEBUG(D_receive) debug_printf("8BITMIME: %d\n", body_8bitmime);
3358 break;
3359 }
d27f98fe
TL
3360 arg_error = TRUE;
3361 break;
059ec3d9 3362
d27f98fe
TL
3363 /* Handle the AUTH extension. If the value given is not "<>" and either
3364 the ACL says "yes" or there is no ACL but the sending host is
3365 authenticated, we set it up as the authenticated sender. However, if the
3366 authenticator set a condition to be tested, we ignore AUTH on MAIL unless
3367 the condition is met. The value of AUTH is an xtext, which means that +,
3368 = and cntrl chars are coded in hex; however "<>" is unaffected by this
3369 coding. */
3370 case ENV_MAIL_OPT_AUTH:
3371 if (Ustrcmp(value, "<>") != 0)
3372 {
3373 int rc;
3374 uschar *ignore_msg;
059ec3d9 3375
d27f98fe
TL
3376 if (auth_xtextdecode(value, &authenticated_sender) < 0)
3377 {
3378 /* Put back terminator overrides for error message */
d27f98fe 3379 value[-1] = '=';
fd98a5c6 3380 name[-1] = ' ';
d27f98fe
TL
3381 done = synprot_error(L_smtp_syntax_error, 501, NULL,
3382 US"invalid data for AUTH");
3383 goto COMMAND_LOOP;
3384 }
3385 if (acl_smtp_mailauth == NULL)
3386 {
3387 ignore_msg = US"client not authenticated";
3388 rc = (sender_host_authenticated != NULL)? OK : FAIL;
3389 }
3390 else
3391 {
3392 ignore_msg = US"rejected by ACL";
3393 rc = acl_check(ACL_WHERE_MAILAUTH, NULL, acl_smtp_mailauth,
3394 &user_msg, &log_msg);
3395 }
3396
3397 switch (rc)
3398 {
3399 case OK:
3400 if (authenticated_by == NULL ||
3401 authenticated_by->mail_auth_condition == NULL ||
3402 expand_check_condition(authenticated_by->mail_auth_condition,
3403 authenticated_by->name, US"authenticator"))
3404 break; /* Accept the AUTH */
3405
3406 ignore_msg = US"server_mail_auth_condition failed";
3407 if (authenticated_id != NULL)
3408 ignore_msg = string_sprintf("%s: authenticated ID=\"%s\"",
3409 ignore_msg, authenticated_id);
3410
3411 /* Fall through */
3412
3413 case FAIL:
3414 authenticated_sender = NULL;
3415 log_write(0, LOG_MAIN, "ignoring AUTH=%s from %s (%s)",
3416 value, host_and_ident(TRUE), ignore_msg);
3417 break;
3418
3419 /* Should only get DEFER or ERROR here. Put back terminator
3420 overrides for error message */
3421
3422 default:
d27f98fe 3423 value[-1] = '=';
fd98a5c6 3424 name[-1] = ' ';
d27f98fe
TL
3425 (void)smtp_handle_acl_fail(ACL_WHERE_MAILAUTH, rc, user_msg,
3426 log_msg);
3427 goto COMMAND_LOOP;
3428 }
059ec3d9 3429 }
d27f98fe 3430 break;
fd98a5c6
JH
3431
3432#ifdef EXPERIMENTAL_PRDR
3433 case ENV_MAIL_OPT_PRDR:
3434 if ( prdr_enable )
3435 prdr_requested = TRUE;
3436 break;
3437#endif
3438
d27f98fe 3439 /* Unknown option. Stick back the terminator characters and break
fd98a5c6
JH
3440 the loop. Do the name-terminator second as extract_option sets
3441 value==name when it found no equal-sign.
3442 An error for a malformed address will occur. */
d27f98fe 3443 default:
d27f98fe 3444 value[-1] = '=';
fd98a5c6
JH
3445 name[-1] = ' ';
3446 arg_error = TRUE;
d27f98fe 3447 break;
059ec3d9 3448 }
d27f98fe
TL
3449 /* Break out of for loop if switch() had bad argument or
3450 when start of the email address is reached */
3451 if (arg_error) break;
059ec3d9
PH
3452 }
3453
3454 /* If we have passed the threshold for rate limiting, apply the current
3455 delay, and update it for next time, provided this is a limited host. */
3456
3457 if (smtp_mailcmd_count > smtp_rlm_threshold &&
3458 verify_check_host(&smtp_ratelimit_hosts) == OK)
3459 {
3460 DEBUG(D_receive) debug_printf("rate limit MAIL: delay %.3g sec\n",
3461 smtp_delay_mail/1000.0);
3462 millisleep((int)smtp_delay_mail);
3463 smtp_delay_mail *= smtp_rlm_factor;
3464 if (smtp_delay_mail > (double)smtp_rlm_limit)
3465 smtp_delay_mail = (double)smtp_rlm_limit;
3466 }
3467
3468 /* Now extract the address, first applying any SMTP-time rewriting. The
3469 TRUE flag allows "<>" as a sender address. */
3470
3471 raw_sender = ((rewrite_existflags & rewrite_smtp) != 0)?
ca86f471
PH
3472 rewrite_one(smtp_cmd_data, rewrite_smtp, NULL, FALSE, US"",
3473 global_rewrite_rules) : smtp_cmd_data;
059ec3d9
PH
3474
3475 /* rfc821_domains = TRUE; << no longer needed */
3476 raw_sender =
3477 parse_extract_address(raw_sender, &errmess, &start, &end, &sender_domain,
3478 TRUE);
3479 /* rfc821_domains = FALSE; << no longer needed */
3480
3481 if (raw_sender == NULL)
3482 {
ca86f471 3483 done = synprot_error(L_smtp_syntax_error, 501, smtp_cmd_data, errmess);
059ec3d9
PH
3484 break;
3485 }
3486
3487 sender_address = raw_sender;
3488
3489 /* If there is a configured size limit for mail, check that this message
3490 doesn't exceed it. The check is postponed to this point so that the sender
3491 can be logged. */
3492
3493 if (thismessage_size_limit > 0 && message_size > thismessage_size_limit)
3494 {
3495 smtp_printf("552 Message size exceeds maximum permitted\r\n");
3496 log_write(L_size_reject,
3497 LOG_MAIN|LOG_REJECT, "rejected MAIL FROM:<%s> %s: "
3498 "message too big: size%s=%d max=%d",
3499 sender_address,
3500 host_and_ident(TRUE),
3501 (message_size == INT_MAX)? ">" : "",
3502 message_size,
3503 thismessage_size_limit);
3504 sender_address = NULL;
3505 break;
3506 }
3507
3508 /* Check there is enough space on the disk unless configured not to.
3509 When smtp_check_spool_space is set, the check is for thismessage_size_limit
3510 plus the current message - i.e. we accept the message only if it won't
3511 reduce the space below the threshold. Add 5000 to the size to allow for
3512 overheads such as the Received: line and storing of recipients, etc.
3513 By putting the check here, even when SIZE is not given, it allow VRFY
3514 and EXPN etc. to be used when space is short. */
3515
3516 if (!receive_check_fs(
3517 (smtp_check_spool_space && message_size >= 0)?
3518 message_size + 5000 : 0))
3519 {
3520 smtp_printf("452 Space shortage, please try later\r\n");
3521 sender_address = NULL;
3522 break;
3523 }
3524
3525 /* If sender_address is unqualified, reject it, unless this is a locally
3526 generated message, or the sending host or net is permitted to send
3527 unqualified addresses - typically local machines behaving as MUAs -
3528 in which case just qualify the address. The flag is set above at the start
3529 of the SMTP connection. */
3530
3531 if (sender_domain == 0 && sender_address[0] != 0)
3532 {
3533 if (allow_unqualified_sender)
3534 {
3535 sender_domain = Ustrlen(sender_address) + 1;
3536 sender_address = rewrite_address_qualify(sender_address, FALSE);
3537 DEBUG(D_receive) debug_printf("unqualified address %s accepted\n",
3538 raw_sender);
3539 }
3540 else
3541 {
3542 smtp_printf("501 %s: sender address must contain a domain\r\n",
ca86f471 3543 smtp_cmd_data);
059ec3d9
PH
3544 log_write(L_smtp_syntax_error,
3545 LOG_MAIN|LOG_REJECT,
3546 "unqualified sender rejected: <%s> %s%s",
3547 raw_sender,
3548 host_and_ident(TRUE),
3549 host_lookup_msg);
3550 sender_address = NULL;
3551 break;
3552 }
3553 }
3554
a14e5636
PH
3555 /* Apply an ACL check if one is defined, before responding. Afterwards,
3556 when pipelining is not advertised, do another sync check in case the ACL
3557 delayed and the client started sending in the meantime. */
059ec3d9 3558
a14e5636
PH
3559 if (acl_smtp_mail == NULL) rc = OK; else
3560 {
3561 rc = acl_check(ACL_WHERE_MAIL, NULL, acl_smtp_mail, &user_msg, &log_msg);
3562 if (rc == OK && !pipelining_advertised && !check_sync())
3563 goto SYNC_FAILURE;
3564 }
059ec3d9
PH
3565
3566 if (rc == OK || rc == DISCARD)
3567 {
fd98a5c6
JH
3568 if (user_msg == NULL)
3569 smtp_printf("%s%s%s", US"250 OK",
3570 #ifdef EXPERIMENTAL_PRDR
3571 prdr_requested == TRUE ? US", PRDR Requested" :
3572 #endif
3573 US"",
3574 US"\r\n");
3575 else
3576 {
3577 #ifdef EXPERIMENTAL_PRDR
3578 if ( prdr_requested == TRUE )
3579 user_msg = string_sprintf("%s%s", user_msg, US", PRDR Requested");
3580 #endif
3581 smtp_user_msg(US"250",user_msg);
3582 }
059ec3d9
PH
3583 smtp_delay_rcpt = smtp_rlr_base;
3584 recipients_discarded = (rc == DISCARD);
3585 was_rej_mail = FALSE;
3586 }
059ec3d9
PH
3587 else
3588 {
3589 done = smtp_handle_acl_fail(ACL_WHERE_MAIL, rc, user_msg, log_msg);
3590 sender_address = NULL;
3591 }
3592 break;
3593
3594
2679d413
PH
3595 /* The RCPT command requires an address as an operand. There may be any
3596 number of RCPT commands, specifying multiple recipients. We build them all
3597 into a data structure. The start/end values given by parse_extract_address
3598 are not used, as we keep only the extracted address. */
059ec3d9
PH
3599
3600 case RCPT_CMD:
b4ed4da0 3601 HAD(SCH_RCPT);
059ec3d9 3602 rcpt_count++;
2679d413 3603 was_rcpt = rcpt_in_progress = TRUE;
059ec3d9
PH
3604
3605 /* There must be a sender address; if the sender was rejected and
3606 pipelining was advertised, we assume the client was pipelining, and do not
3607 count this as a protocol error. Reset was_rej_mail so that further RCPTs
3608 get the same treatment. */
3609
3610 if (sender_address == NULL)
3611 {
3612 if (pipelining_advertised && last_was_rej_mail)
3613 {
3614 smtp_printf("503 sender not yet given\r\n");
3615 was_rej_mail = TRUE;
3616 }
3617 else
3618 {
3619 done = synprot_error(L_smtp_protocol_error, 503, NULL,
3620 US"sender not yet given");
3621 was_rcpt = FALSE; /* Not a valid RCPT */
3622 }
3623 rcpt_fail_count++;
3624 break;
3625 }
3626
3627 /* Check for an operand */
3628
ca86f471 3629 if (smtp_cmd_data[0] == 0)
059ec3d9
PH
3630 {
3631 done = synprot_error(L_smtp_syntax_error, 501, NULL,
3632 US"RCPT must have an address operand");
3633 rcpt_fail_count++;
3634 break;
3635 }
3636
3637 /* Apply SMTP rewriting then extract the working address. Don't allow "<>"
3638 as a recipient address */
3639
3640 recipient = ((rewrite_existflags & rewrite_smtp) != 0)?
ca86f471
PH
3641 rewrite_one(smtp_cmd_data, rewrite_smtp, NULL, FALSE, US"",
3642 global_rewrite_rules) : smtp_cmd_data;
059ec3d9
PH
3643
3644 /* rfc821_domains = TRUE; << no longer needed */
3645 recipient = parse_extract_address(recipient, &errmess, &start, &end,
3646 &recipient_domain, FALSE);
3647 /* rfc821_domains = FALSE; << no longer needed */
3648
3649 if (recipient == NULL)
3650 {
ca86f471 3651 done = synprot_error(L_smtp_syntax_error, 501, smtp_cmd_data, errmess);
059ec3d9
PH
3652 rcpt_fail_count++;
3653 break;
3654 }
3655
3656 /* If the recipient address is unqualified, reject it, unless this is a
3657 locally generated message. However, unqualified addresses are permitted
3658 from a configured list of hosts and nets - typically when behaving as
3659 MUAs rather than MTAs. Sad that SMTP is used for both types of traffic,
3660 really. The flag is set at the start of the SMTP connection.
3661
3662 RFC 1123 talks about supporting "the reserved mailbox postmaster"; I always
3663 assumed this meant "reserved local part", but the revision of RFC 821 and
3664 friends now makes it absolutely clear that it means *mailbox*. Consequently
3665 we must always qualify this address, regardless. */
3666
3667 if (recipient_domain == 0)
3668 {
3669 if (allow_unqualified_recipient ||
3670 strcmpic(recipient, US"postmaster") == 0)
3671 {
3672 DEBUG(D_receive) debug_printf("unqualified address %s accepted\n",
3673 recipient);
3674 recipient_domain = Ustrlen(recipient) + 1;
3675 recipient = rewrite_address_qualify(recipient, TRUE);
3676 }
3677 else
3678 {
3679 rcpt_fail_count++;
3680 smtp_printf("501 %s: recipient address must contain a domain\r\n",
ca86f471 3681 smtp_cmd_data);
059ec3d9
PH
3682 log_write(L_smtp_syntax_error,
3683 LOG_MAIN|LOG_REJECT, "unqualified recipient rejected: "
3684 "<%s> %s%s", recipient, host_and_ident(TRUE),
3685 host_lookup_msg);
3686 break;
3687 }
3688 }
3689
3690 /* Check maximum allowed */
3691
3692 if (rcpt_count > recipients_max && recipients_max > 0)
3693 {
3694 if (recipients_max_reject)
3695 {
3696 rcpt_fail_count++;
3697 smtp_printf("552 too many recipients\r\n");
3698 if (!toomany)
3699 log_write(0, LOG_MAIN|LOG_REJECT, "too many recipients: message "
3700 "rejected: sender=<%s> %s", sender_address, host_and_ident(TRUE));
3701 }
3702 else
3703 {
3704 rcpt_defer_count++;
3705 smtp_printf("452 too many recipients\r\n");
3706 if (!toomany)
3707 log_write(0, LOG_MAIN|LOG_REJECT, "too many recipients: excess "
3708 "temporarily rejected: sender=<%s> %s", sender_address,
3709 host_and_ident(TRUE));
3710 }
3711
3712 toomany = TRUE;
3713 break;
3714 }
3715
3716 /* If we have passed the threshold for rate limiting, apply the current
3717 delay, and update it for next time, provided this is a limited host. */
3718
3719 if (rcpt_count > smtp_rlr_threshold &&
3720 verify_check_host(&smtp_ratelimit_hosts) == OK)
3721 {
3722 DEBUG(D_receive) debug_printf("rate limit RCPT: delay %.3g sec\n",
3723 smtp_delay_rcpt/1000.0);
3724 millisleep((int)smtp_delay_rcpt);
3725 smtp_delay_rcpt *= smtp_rlr_factor;
3726 if (smtp_delay_rcpt > (double)smtp_rlr_limit)
3727 smtp_delay_rcpt = (double)smtp_rlr_limit;
3728 }
3729
3730 /* If the MAIL ACL discarded all the recipients, we bypass ACL checking
a14e5636
PH
3731 for them. Otherwise, check the access control list for this recipient. As
3732 there may be a delay in this, re-check for a synchronization error
3733 afterwards, unless pipelining was advertised. */
059ec3d9 3734
a14e5636
PH
3735 if (recipients_discarded) rc = DISCARD; else
3736 {
3737 rc = acl_check(ACL_WHERE_RCPT, recipient, acl_smtp_rcpt, &user_msg,
3738 &log_msg);
3739 if (rc == OK && !pipelining_advertised && !check_sync())
3740 goto SYNC_FAILURE;
3741 }
059ec3d9
PH
3742
3743 /* The ACL was happy */
3744
3745 if (rc == OK)
3746 {
4e88a19f
PH
3747 if (user_msg == NULL) smtp_printf("250 Accepted\r\n");
3748 else smtp_user_msg(US"250", user_msg);
059ec3d9
PH
3749 receive_add_recipient(recipient, -1);
3750 }
3751
3752 /* The recipient was discarded */
3753
3754 else if (rc == DISCARD)
3755 {
4e88a19f
PH
3756 if (user_msg == NULL) smtp_printf("250 Accepted\r\n");
3757 else smtp_user_msg(US"250", user_msg);
059ec3d9
PH
3758 rcpt_fail_count++;
3759 discarded = TRUE;
3760 log_write(0, LOG_MAIN|LOG_REJECT, "%s F=<%s> rejected RCPT %s: "
3761 "discarded by %s ACL%s%s", host_and_ident(TRUE),
3762 (sender_address_unrewritten != NULL)?
3763 sender_address_unrewritten : sender_address,
3ee512ff 3764 smtp_cmd_argument, recipients_discarded? "MAIL" : "RCPT",
059ec3d9
PH
3765 (log_msg == NULL)? US"" : US": ",
3766 (log_msg == NULL)? US"" : log_msg);
3767 }
3768
3769 /* Either the ACL failed the address, or it was deferred. */
3770
3771 else
3772 {
3773 if (rc == FAIL) rcpt_fail_count++; else rcpt_defer_count++;
3774 done = smtp_handle_acl_fail(ACL_WHERE_RCPT, rc, user_msg, log_msg);
3775 }
3776 break;
3777
3778
3779 /* The DATA command is legal only if it follows successful MAIL FROM
3780 and RCPT TO commands. However, if pipelining is advertised, a bad DATA is
3781 not counted as a protocol error if it follows RCPT (which must have been
3782 rejected if there are no recipients.) This function is complete when a
3783 valid DATA command is encountered.
3784
3785 Note concerning the code used: RFC 2821 says this:
3786
3787 - If there was no MAIL, or no RCPT, command, or all such commands
3788 were rejected, the server MAY return a "command out of sequence"
3789 (503) or "no valid recipients" (554) reply in response to the
3790 DATA command.
3791
3792 The example in the pipelining RFC 2920 uses 554, but I use 503 here
2679d413
PH
3793 because it is the same whether pipelining is in use or not.
3794
3795 If all the RCPT commands that precede DATA provoked the same error message
3796 (often indicating some kind of system error), it is helpful to include it
3797 with the DATA rejection (an idea suggested by Tony Finch). */
059ec3d9
PH
3798
3799 case DATA_CMD:
b4ed4da0 3800 HAD(SCH_DATA);