Avoid trying to talk TLS over a known-closed channel
[exim.git] / src / src / smtp_in.c
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1/*************************************************
2* Exim - an Internet mail transport agent *
3*************************************************/
4
f9ba5e22 5/* Copyright (c) University of Cambridge 1995 - 2018 */
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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"
2ef7ed08 12#include <assert.h>
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13
14
15/* Initialize for TCP wrappers if so configured. It appears that the macro
16HAVE_IPV6 is used in some versions of the tcpd.h header, so we unset it before
17including that header, and restore its value afterwards. */
18
19#ifdef USE_TCP_WRAPPERS
20
21 #if HAVE_IPV6
22 #define EXIM_HAVE_IPV6
23 #endif
24 #undef HAVE_IPV6
25 #include <tcpd.h>
26 #undef HAVE_IPV6
27 #ifdef EXIM_HAVE_IPV6
28 #define HAVE_IPV6 TRUE
29 #endif
30
31int allow_severity = LOG_INFO;
32int deny_severity = LOG_NOTICE;
5dc43717 33uschar *tcp_wrappers_name;
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34#endif
35
36
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37/* Size of buffer for reading SMTP commands. We used to use 512, as defined
38by RFC 821. However, RFC 1869 specifies that this must be increased for SMTP
39commands that accept arguments, and this in particular applies to AUTH, where
94431adb 40the data can be quite long. More recently this value was 2048 in Exim;
e2ca7082 41however, RFC 4954 (circa 2007) recommends 12288 bytes to handle AUTH. Clients
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42such as Thunderbird will send an AUTH with an initial-response for GSSAPI.
43The maximum size of a Kerberos ticket under Windows 2003 is 12000 bytes, and
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44we need room to handle large base64-encoded AUTHs for GSSAPI.
45*/
46
bd8fbe36 47#define SMTP_CMD_BUFFER_SIZE 16384
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48
49/* Size of buffer for reading SMTP incoming packets */
50
bd8fbe36 51#define IN_BUFFER_SIZE 8192
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52
53/* Structure for SMTP command list */
54
55typedef struct {
1ba28e2b 56 const char *name;
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57 int len;
58 short int cmd;
59 short int has_arg;
60 short int is_mail_cmd;
61} smtp_cmd_list;
62
63/* Codes for identifying commands. We order them so that those that come first
64are those for which synchronization is always required. Checking this can help
65block some spam. */
66
67enum {
68 /* These commands are required to be synchronized, i.e. to be the last in a
69 block of commands when pipelining. */
70
71 HELO_CMD, EHLO_CMD, DATA_CMD, /* These are listed in the pipelining */
72 VRFY_CMD, EXPN_CMD, NOOP_CMD, /* RFC as requiring synchronization */
73 ETRN_CMD, /* This by analogy with TURN from the RFC */
74 STARTTLS_CMD, /* Required by the STARTTLS RFC */
b3ef41c9 75 TLS_AUTH_CMD, /* auto-command at start of SSL */
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76
77 /* This is a dummy to identify the non-sync commands when pipelining */
78
79 NON_SYNC_CMD_PIPELINING,
80
81 /* These commands need not be synchronized when pipelining */
82
83 MAIL_CMD, RCPT_CMD, RSET_CMD,
84
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85 /* This is a dummy to identify the non-sync commands when not pipelining */
86
87 NON_SYNC_CMD_NON_PIPELINING,
88
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89 /* RFC3030 section 2: "After all MAIL and RCPT responses are collected and
90 processed the message is sent using a series of BDAT commands"
91 implies that BDAT should be synchronized. However, we see Google, at least,
92 sending MAIL,RCPT,BDAT-LAST in a single packet, clearly not waiting for
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93 processing of the RCPT response(s). We shall do the same, and not require
94 synch for BDAT. Worse, as the chunk may (very likely will) follow the
95 command-header in the same packet we cannot do the usual "is there any
4c04137d 96 follow-on data after the command line" even for non-pipeline mode.
f4630439 97 So we'll need an explicit check after reading the expected chunk amount
4c04137d 98 when non-pipe, before sending the ACK. */
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99
100 BDAT_CMD,
101
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102 /* I have been unable to find a statement about the use of pipelining
103 with AUTH, so to be on the safe side it is here, though I kind of feel
104 it should be up there with the synchronized commands. */
105
106 AUTH_CMD,
107
108 /* I'm not sure about these, but I don't think they matter. */
109
110 QUIT_CMD, HELP_CMD,
111
cee5f132 112#ifdef SUPPORT_PROXY
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113 PROXY_FAIL_IGNORE_CMD,
114#endif
115
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116 /* These are specials that don't correspond to actual commands */
117
118 EOF_CMD, OTHER_CMD, BADARG_CMD, BADCHAR_CMD, BADSYN_CMD,
119 TOO_MANY_NONMAIL_CMD };
120
121
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122/* This is a convenience macro for adding the identity of an SMTP command
123to the circular buffer that holds a list of the last n received. */
124
125#define HAD(n) \
126 smtp_connection_had[smtp_ch_index++] = n; \
127 if (smtp_ch_index >= SMTP_HBUFF_SIZE) smtp_ch_index = 0
128
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129
130/*************************************************
131* Local static variables *
132*************************************************/
133
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134static struct {
135 BOOL auth_advertised :1;
059ec3d9 136#ifdef SUPPORT_TLS
88752192 137 BOOL tls_advertised :1;
8ac90765 138# ifdef EXPERIMENTAL_REQUIRETLS
88752192 139 BOOL requiretls_advertised :1;
8ac90765 140# endif
059ec3d9 141#endif
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142 BOOL dsn_advertised :1;
143 BOOL esmtp :1;
144 BOOL helo_required :1;
145 BOOL helo_verify :1;
146 BOOL helo_seen :1;
147 BOOL helo_accept_junk :1;
148 BOOL rcpt_smtp_response_same :1;
149 BOOL rcpt_in_progress :1;
150 BOOL smtp_exit_function_called :1;
8c5d388a 151#ifdef SUPPORT_I18N
88752192 152 BOOL smtputf8_advertised :1;
d1a13eea 153#endif
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154} fl = {
155 .helo_required = FALSE,
156 .helo_verify = FALSE,
157 .smtp_exit_function_called = FALSE,
158};
159
160static auth_instance *authenticated_by;
161static int count_nonmail;
162static int nonmail_command_count;
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163static int synprot_error_count;
164static int unknown_command_count;
165static int sync_cmd_limit;
166static int smtp_write_error = 0;
167
2679d413 168static uschar *rcpt_smtp_response;
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169static uschar *smtp_data_buffer;
170static uschar *smtp_cmd_data;
171
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172/* We need to know the position of RSET, HELO, EHLO, AUTH, and STARTTLS. Their
173final fields of all except AUTH are forced TRUE at the start of a new message
174setup, to allow one of each between messages that is not counted as a nonmail
175command. (In fact, only one of HELO/EHLO is not counted.) Also, we have to
176allow a new EHLO after starting up TLS.
177
178AUTH is "falsely" labelled as a mail command initially, so that it doesn't get
179counted. However, the flag is changed when AUTH is received, so that multiple
180failing AUTHs will eventually hit the limit. After a successful AUTH, another
181AUTH is already forbidden. After a TLS session is started, AUTH's flag is again
182forced TRUE, to allow for the re-authentication that can happen at that point.
183
184QUIT is also "falsely" labelled as a mail command so that it doesn't up the
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185count of non-mail commands and possibly provoke an error.
186
187tls_auth is a pseudo-command, never expected in input. It is activated
188on TLS startup and looks for a tls authenticator. */
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189
190static smtp_cmd_list cmd_list[] = {
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191 /* name len cmd has_arg is_mail_cmd */
192
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193 { "rset", sizeof("rset")-1, RSET_CMD, FALSE, FALSE }, /* First */
194 { "helo", sizeof("helo")-1, HELO_CMD, TRUE, FALSE },
195 { "ehlo", sizeof("ehlo")-1, EHLO_CMD, TRUE, FALSE },
196 { "auth", sizeof("auth")-1, AUTH_CMD, TRUE, TRUE },
e0574cb5 197#ifdef SUPPORT_TLS
059ec3d9 198 { "starttls", sizeof("starttls")-1, STARTTLS_CMD, FALSE, FALSE },
69d8eed7 199 { "tls_auth", 0, TLS_AUTH_CMD, FALSE, FALSE },
e0574cb5 200#endif
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201
202/* If you change anything above here, also fix the definitions below. */
203
204 { "mail from:", sizeof("mail from:")-1, MAIL_CMD, TRUE, TRUE },
205 { "rcpt to:", sizeof("rcpt to:")-1, RCPT_CMD, TRUE, TRUE },
206 { "data", sizeof("data")-1, DATA_CMD, FALSE, TRUE },
18481de3 207 { "bdat", sizeof("bdat")-1, BDAT_CMD, TRUE, TRUE },
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208 { "quit", sizeof("quit")-1, QUIT_CMD, FALSE, TRUE },
209 { "noop", sizeof("noop")-1, NOOP_CMD, TRUE, FALSE },
210 { "etrn", sizeof("etrn")-1, ETRN_CMD, TRUE, FALSE },
211 { "vrfy", sizeof("vrfy")-1, VRFY_CMD, TRUE, FALSE },
212 { "expn", sizeof("expn")-1, EXPN_CMD, TRUE, FALSE },
213 { "help", sizeof("help")-1, HELP_CMD, TRUE, FALSE }
214};
215
216static smtp_cmd_list *cmd_list_end =
217 cmd_list + sizeof(cmd_list)/sizeof(smtp_cmd_list);
218
219#define CMD_LIST_RSET 0
220#define CMD_LIST_HELO 1
221#define CMD_LIST_EHLO 2
222#define CMD_LIST_AUTH 3
223#define CMD_LIST_STARTTLS 4
b3ef41c9 224#define CMD_LIST_TLS_AUTH 5
059ec3d9 225
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226/* This list of names is used for performing the smtp_no_mail logging action.
227It must be kept in step with the SCH_xxx enumerations. */
228
229static uschar *smtp_names[] =
230 {
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231 US"NONE", US"AUTH", US"DATA", US"BDAT", US"EHLO", US"ETRN", US"EXPN",
232 US"HELO", US"HELP", US"MAIL", US"NOOP", US"QUIT", US"RCPT", US"RSET",
233 US"STARTTLS", US"VRFY" };
b4ed4da0 234
e524074d 235static uschar *protocols_local[] = {
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236 US"local-smtp", /* HELO */
237 US"local-smtps", /* The rare case EHLO->STARTTLS->HELO */
238 US"local-esmtp", /* EHLO */
239 US"local-esmtps", /* EHLO->STARTTLS->EHLO */
240 US"local-esmtpa", /* EHLO->AUTH */
241 US"local-esmtpsa" /* EHLO->STARTTLS->EHLO->AUTH */
059ec3d9 242 };
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243static uschar *protocols[] = {
244 US"smtp", /* HELO */
245 US"smtps", /* The rare case EHLO->STARTTLS->HELO */
246 US"esmtp", /* EHLO */
247 US"esmtps", /* EHLO->STARTTLS->EHLO */
248 US"esmtpa", /* EHLO->AUTH */
249 US"esmtpsa" /* EHLO->STARTTLS->EHLO->AUTH */
250 };
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251
252#define pnormal 0
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253#define pextend 2
254#define pcrpted 1 /* added to pextend or pnormal */
255#define pauthed 2 /* added to pextend */
059ec3d9 256
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257/* Sanity check and validate optional args to MAIL FROM: envelope */
258enum {
2ef7ed08 259 ENV_MAIL_OPT_NULL,
d27f98fe 260 ENV_MAIL_OPT_SIZE, ENV_MAIL_OPT_BODY, ENV_MAIL_OPT_AUTH,
8ccd00b1 261#ifndef DISABLE_PRDR
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262 ENV_MAIL_OPT_PRDR,
263#endif
6c1c3d1d 264 ENV_MAIL_OPT_RET, ENV_MAIL_OPT_ENVID,
8c5d388a 265#ifdef SUPPORT_I18N
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266 ENV_MAIL_OPT_UTF8,
267#endif
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268#ifdef EXPERIMENTAL_REQUIRETLS
269 ENV_MAIL_OPT_REQTLS,
270#endif
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271 };
272typedef struct {
273 uschar * name; /* option requested during MAIL cmd */
274 int value; /* enum type */
275 BOOL need_value; /* TRUE requires value (name=value pair format)
276 FALSE is a singleton */
277 } env_mail_type_t;
278static env_mail_type_t env_mail_type_list[] = {
279 { US"SIZE", ENV_MAIL_OPT_SIZE, TRUE },
280 { US"BODY", ENV_MAIL_OPT_BODY, TRUE },
281 { US"AUTH", ENV_MAIL_OPT_AUTH, TRUE },
8ccd00b1 282#ifndef DISABLE_PRDR
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283 { US"PRDR", ENV_MAIL_OPT_PRDR, FALSE },
284#endif
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285 { US"RET", ENV_MAIL_OPT_RET, TRUE },
286 { US"ENVID", ENV_MAIL_OPT_ENVID, TRUE },
8c5d388a 287#ifdef SUPPORT_I18N
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288 { US"SMTPUTF8",ENV_MAIL_OPT_UTF8, FALSE }, /* rfc6531 */
289#endif
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290#ifdef EXPERIMENTAL_REQUIRETLS
291 /* https://tools.ietf.org/html/draft-ietf-uta-smtp-require-tls-03 */
292 { US"REQUIRETLS",ENV_MAIL_OPT_REQTLS, FALSE },
293#endif
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294 /* keep this the last entry */
295 { US"NULL", ENV_MAIL_OPT_NULL, FALSE },
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296 };
297
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298/* When reading SMTP from a remote host, we have to use our own versions of the
299C input-reading functions, in order to be able to flush the SMTP output only
300when about to read more data from the socket. This is the only way to get
301optimal performance when the client is using pipelining. Flushing for every
302command causes a separate packet and reply packet each time; saving all the
303responses up (when pipelining) combines them into one packet and one response.
304
305For simplicity, these functions are used for *all* SMTP input, not only when
306receiving over a socket. However, after setting up a secure socket (SSL), input
307is read via the OpenSSL library, and another set of functions is used instead
308(see tls.c).
309
310These functions are set in the receive_getc etc. variables and called with the
311same interface as the C functions. However, since there can only ever be
312one incoming SMTP call, we just use a single buffer and flags. There is no need
313to implement a complicated private FILE-like structure.*/
314
315static uschar *smtp_inbuffer;
316static uschar *smtp_inptr;
317static uschar *smtp_inend;
318static int smtp_had_eof;
319static int smtp_had_error;
320
321
7e3ce68e 322/* forward declarations */
bd8fbe36 323static int smtp_read_command(BOOL check_sync, unsigned buffer_lim);
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324static int synprot_error(int type, int code, uschar *data, uschar *errmess);
325static void smtp_quit_handler(uschar **, uschar **);
326static void smtp_rset_handler(void);
327
059ec3d9 328/*************************************************
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329* Recheck synchronization *
330*************************************************/
331
332/* Synchronization checks can never be perfect because a packet may be on its
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333way but not arrived when the check is done. Normally, the checks happen when
334commands are read: Exim ensures that there is no more input in the input buffer.
335In normal cases, the response to the command will be fast, and there is no
336further check.
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337
338However, for some commands an ACL is run, and that can include delays. In those
339cases, it is useful to do another check on the input just before sending the
340response. This also applies at the start of a connection. This function does
341that check by means of the select() function, as long as the facility is not
342disabled or inappropriate. A failure of select() is ignored.
343
344When there is unwanted input, we read it so that it appears in the log of the
345error.
346
347Arguments: none
348Returns: TRUE if all is well; FALSE if there is input pending
349*/
350
351static BOOL
925ac8e4 352wouldblock_reading(void)
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353{
354int fd, rc;
355fd_set fds;
356struct timeval tzero;
357
9067f574 358#ifdef SUPPORT_TLS
74f1a423 359if (tls_in.active.sock >= 0)
e5de01f0 360 return !tls_could_read();
9067f574 361#endif
f4630439 362
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363if (smtp_inptr < smtp_inend)
364 return FALSE;
365
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366fd = fileno(smtp_in);
367FD_ZERO(&fds);
368FD_SET(fd, &fds);
369tzero.tv_sec = 0;
370tzero.tv_usec = 0;
371rc = select(fd + 1, (SELECT_ARG2_TYPE *)&fds, NULL, NULL, &tzero);
372
373if (rc <= 0) return TRUE; /* Not ready to read */
bd8fbe36 374rc = smtp_getc(GETC_BUFFER_UNLIMITED);
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375if (rc < 0) return TRUE; /* End of file or error */
376
377smtp_ungetc(rc);
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378return FALSE;
379}
380
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381static BOOL
382check_sync(void)
383{
8768d548 384if (!smtp_enforce_sync || !sender_host_address || f.sender_host_notsocket)
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385 return TRUE;
386
387return wouldblock_reading();
388}
389
390
391/* If there's input waiting (and we're doing pipelineing) then we can pipeline
392a reponse with the one following. */
393
394static BOOL
395pipeline_response(void)
396{
397if ( !smtp_enforce_sync || !sender_host_address
8768d548 398 || f.sender_host_notsocket || !f.smtp_in_pipelining_advertised)
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399 return FALSE;
400
3fc73bdc 401if (wouldblock_reading()) return FALSE;
8768d548 402f.smtp_in_pipelining_used = TRUE;
3fc73bdc 403return TRUE;
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404}
405
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406
407
408/*************************************************
409* Log incomplete transactions *
410*************************************************/
411
412/* This function is called after a transaction has been aborted by RSET, QUIT,
413connection drops or other errors. It logs the envelope information received
414so far in order to preserve address verification attempts.
415
416Argument: string to indicate what aborted the transaction
417Returns: nothing
418*/
419
420static void
421incomplete_transaction_log(uschar *what)
422{
423if (sender_address == NULL || /* No transaction in progress */
424 !LOGGING(smtp_incomplete_transaction))
425 return;
426
427/* Build list of recipients for logging */
428
429if (recipients_count > 0)
430 {
431 int i;
432 raw_recipients = store_get(recipients_count * sizeof(uschar *));
433 for (i = 0; i < recipients_count; i++)
434 raw_recipients[i] = recipients_list[i].address;
435 raw_recipients_count = recipients_count;
436 }
437
438log_write(L_smtp_incomplete_transaction, LOG_MAIN|LOG_SENDER|LOG_RECIPIENTS,
439 "%s incomplete transaction (%s)", host_and_ident(TRUE), what);
440}
441
442
443
444
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445void
446smtp_command_timeout_exit(void)
447{
448log_write(L_lost_incoming_connection,
449 LOG_MAIN, "SMTP command timeout on%s connection from %s",
74f1a423 450 tls_in.active.sock >= 0 ? " TLS" : "", host_and_ident(FALSE));
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451if (smtp_batched_input)
452 moan_smtp_batch(NULL, "421 SMTP command timeout"); /* Does not return */
453smtp_notquit_exit(US"command-timeout", US"421",
454 US"%s: SMTP command timeout - closing connection",
455 smtp_active_hostname);
456exim_exit(EXIT_FAILURE, US"receiving");
457}
458
459void
460smtp_command_sigterm_exit(void)
461{
462log_write(0, LOG_MAIN, "%s closed after SIGTERM", smtp_get_connection_info());
463if (smtp_batched_input)
464 moan_smtp_batch(NULL, "421 SIGTERM received"); /* Does not return */
465smtp_notquit_exit(US"signal-exit", US"421",
466 US"%s: Service not available - closing connection", smtp_active_hostname);
467exim_exit(EXIT_FAILURE, US"receiving");
468}
469
470void
471smtp_data_timeout_exit(void)
472{
473log_write(L_lost_incoming_connection,
474 LOG_MAIN, "SMTP data timeout (message abandoned) on connection from %s F=<%s>",
475 sender_fullhost ? sender_fullhost : US"local process", sender_address);
476receive_bomb_out(US"data-timeout", US"SMTP incoming data timeout");
477/* Does not return */
478}
479
480void
481smtp_data_sigint_exit(void)
482{
483log_write(0, LOG_MAIN, "%s closed after %s",
484 smtp_get_connection_info(), had_data_sigint == SIGTERM ? "SIGTERM":"SIGINT");
485receive_bomb_out(US"signal-exit",
486 US"Service not available - SIGTERM or SIGINT received");
487/* Does not return */
488}
489
490
491
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492/* Refill the buffer, and notify DKIM verification code.
493Return false for error or EOF.
494*/
495
496static BOOL
497smtp_refill(unsigned lim)
498{
499int rc, save_errno;
500if (!smtp_out) return FALSE;
501fflush(smtp_out);
c2a1bba0 502if (smtp_receive_timeout > 0) ALARM(smtp_receive_timeout);
0d81dabc 503
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504/* Limit amount read, so non-message data is not fed to DKIM.
505Take care to not touch the safety NUL at the end of the buffer. */
0d81dabc 506
ecce6d9a 507rc = read(fileno(smtp_in), smtp_inbuffer, MIN(IN_BUFFER_SIZE-1, lim));
0d81dabc 508save_errno = errno;
c2a1bba0 509if (smtp_receive_timeout > 0) ALARM_CLR(0);
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510if (rc <= 0)
511 {
512 /* Must put the error text in fixed store, because this might be during
513 header reading, where it releases unused store above the header. */
514 if (rc < 0)
515 {
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516 if (had_command_timeout) /* set by signal handler */
517 smtp_command_timeout_exit(); /* does not return */
518 if (had_command_sigterm)
519 smtp_command_sigterm_exit();
520 if (had_data_timeout)
521 smtp_data_timeout_exit();
522 if (had_data_sigint)
523 smtp_data_sigint_exit();
524
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525 smtp_had_error = save_errno;
526 smtp_read_error = string_copy_malloc(
527 string_sprintf(" (error: %s)", strerror(save_errno)));
528 }
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529 else
530 smtp_had_eof = 1;
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531 return FALSE;
532 }
533#ifndef DISABLE_DKIM
534dkim_exim_verify_feed(smtp_inbuffer, rc);
535#endif
536smtp_inend = smtp_inbuffer + rc;
537smtp_inptr = smtp_inbuffer;
538return TRUE;
539}
540
f4630439 541/*************************************************
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542* SMTP version of getc() *
543*************************************************/
544
545/* This gets the next byte from the SMTP input buffer. If the buffer is empty,
546it flushes the output, and refills the buffer, with a timeout. The signal
547handler is set appropriately by the calling function. This function is not used
4c04137d 548after a connection has negotiated itself into an TLS/SSL state.
059ec3d9 549
bd8fbe36 550Arguments: lim Maximum amount to read/buffer
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551Returns: the next character or EOF
552*/
553
554int
bd8fbe36 555smtp_getc(unsigned lim)
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556{
557if (smtp_inptr >= smtp_inend)
0d81dabc 558 if (!smtp_refill(lim))
059ec3d9 559 return EOF;
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560return *smtp_inptr++;
561}
562
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563uschar *
564smtp_getbuf(unsigned * len)
565{
566unsigned size;
567uschar * buf;
568
569if (smtp_inptr >= smtp_inend)
570 if (!smtp_refill(*len))
571 { *len = 0; return NULL; }
572
573if ((size = smtp_inend - smtp_inptr) > *len) size = *len;
574buf = smtp_inptr;
575smtp_inptr += size;
576*len = size;
577return buf;
578}
579
584e96c6
JH
580void
581smtp_get_cache(void)
582{
9960d1e5 583#ifndef DISABLE_DKIM
584e96c6
JH
584int n = smtp_inend - smtp_inptr;
585if (n > 0)
586 dkim_exim_verify_feed(smtp_inptr, n);
584e96c6 587#endif
9960d1e5 588}
059ec3d9
PH
589
590
7e3ce68e
JH
591/* Get a byte from the smtp input, in CHUNKING mode. Handle ack of the
592previous BDAT chunk and getting new ones when we run out. Uses the
593underlying smtp_getc or tls_getc both for that and for getting the
594(buffered) data byte. EOD signals (an expected) no further data.
595ERR signals a protocol error, and EOF a closed input stream.
596
597Called from read_bdat_smtp() in receive.c for the message body, but also
598by the headers read loop in receive_msg(); manipulates chunking_state
599to handle the BDAT command/response.
600Placed here due to the correlation with the above smtp_getc(), which it wraps,
601and also by the need to do smtp command/response handling.
602
bd8fbe36 603Arguments: lim (ignored)
7e3ce68e
JH
604Returns: the next character or ERR, EOD or EOF
605*/
606
607int
bd8fbe36 608bdat_getc(unsigned lim)
7e3ce68e
JH
609{
610uschar * user_msg = NULL;
611uschar * log_msg;
612
613for(;;)
614 {
79de4f37 615#ifndef DISABLE_DKIM
64b67b65 616 unsigned dkim_save;
79de4f37
JH
617#endif
618
bd8fbe36
JH
619 if (chunking_data_left > 0)
620 return lwr_receive_getc(chunking_data_left--);
7e3ce68e
JH
621
622 receive_getc = lwr_receive_getc;
0d81dabc 623 receive_getbuf = lwr_receive_getbuf;
7e3ce68e 624 receive_ungetc = lwr_receive_ungetc;
bd8fbe36 625#ifndef DISABLE_DKIM
79de4f37 626 dkim_save = dkim_collect_input;
64b67b65 627 dkim_collect_input = 0;
bd8fbe36 628#endif
7e3ce68e 629
f4630439
JH
630 /* Unless PIPELINING was offered, there should be no next command
631 until after we ack that chunk */
632
8768d548 633 if (!f.smtp_in_pipelining_advertised && !check_sync())
f4630439 634 {
40525d07
JH
635 unsigned n = smtp_inend - smtp_inptr;
636 if (n > 32) n = 32;
637
f4630439
JH
638 incomplete_transaction_log(US"sync failure");
639 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP protocol synchronization error "
640 "(next input sent too soon: pipelining was not advertised): "
9e0ed81f 641 "rejected \"%s\" %s next input=\"%s\"%s",
f4630439 642 smtp_cmd_buffer, host_and_ident(TRUE),
9e0ed81f
JH
643 string_printing(string_copyn(smtp_inptr, n)),
644 smtp_inend - smtp_inptr > n ? "..." : "");
645 (void) synprot_error(L_smtp_protocol_error, 554, NULL,
646 US"SMTP synchronization error");
f4630439
JH
647 goto repeat_until_rset;
648 }
649
7e3ce68e
JH
650 /* If not the last, ack the received chunk. The last response is delayed
651 until after the data ACL decides on it */
7e3ce68e
JH
652
653 if (chunking_state == CHUNKING_LAST)
584e96c6
JH
654 {
655#ifndef DISABLE_DKIM
e983e85a 656 dkim_exim_verify_feed(NULL, 0); /* notify EOD */
584e96c6 657#endif
7e3ce68e 658 return EOD;
584e96c6 659 }
7e3ce68e 660
925ac8e4 661 smtp_printf("250 %u byte chunk received\r\n", FALSE, chunking_datasize);
bd8fbe36
JH
662 chunking_state = CHUNKING_OFFERED;
663 DEBUG(D_receive) debug_printf("chunking state %d\n", (int)chunking_state);
7e3ce68e
JH
664
665 /* Expect another BDAT cmd from input. RFC 3030 says nothing about
666 QUIT, RSET or NOOP but handling them seems obvious */
667
668next_cmd:
bd8fbe36 669 switch(smtp_read_command(TRUE, 1))
7e3ce68e
JH
670 {
671 default:
672 (void) synprot_error(L_smtp_protocol_error, 503, NULL,
673 US"only BDAT permissible after non-LAST BDAT");
674
675 repeat_until_rset:
bd8fbe36 676 switch(smtp_read_command(TRUE, 1))
7e3ce68e
JH
677 {
678 case QUIT_CMD: smtp_quit_handler(&user_msg, &log_msg); /*FALLTHROUGH */
679 case EOF_CMD: return EOF;
680 case RSET_CMD: smtp_rset_handler(); return ERR;
681 default: if (synprot_error(L_smtp_protocol_error, 503, NULL,
682 US"only RSET accepted now") > 0)
683 return EOF;
684 goto repeat_until_rset;
685 }
686
687 case QUIT_CMD:
688 smtp_quit_handler(&user_msg, &log_msg);
689 /*FALLTHROUGH*/
690 case EOF_CMD:
691 return EOF;
692
693 case RSET_CMD:
694 smtp_rset_handler();
695 return ERR;
696
697 case NOOP_CMD:
698 HAD(SCH_NOOP);
925ac8e4 699 smtp_printf("250 OK\r\n", FALSE);
7e3ce68e
JH
700 goto next_cmd;
701
702 case BDAT_CMD:
703 {
704 int n;
705
706 if (sscanf(CS smtp_cmd_data, "%u %n", &chunking_datasize, &n) < 1)
707 {
708 (void) synprot_error(L_smtp_protocol_error, 501, NULL,
709 US"missing size for BDAT command");
710 return ERR;
711 }
712 chunking_state = strcmpic(smtp_cmd_data+n, US"LAST") == 0
713 ? CHUNKING_LAST : CHUNKING_ACTIVE;
714 chunking_data_left = chunking_datasize;
bd8fbe36
JH
715 DEBUG(D_receive) debug_printf("chunking state %d, %d bytes\n",
716 (int)chunking_state, chunking_data_left);
7e3ce68e
JH
717
718 if (chunking_datasize == 0)
719 if (chunking_state == CHUNKING_LAST)
720 return EOD;
721 else
722 {
723 (void) synprot_error(L_smtp_protocol_error, 504, NULL,
724 US"zero size for BDAT command");
725 goto repeat_until_rset;
726 }
727
728 receive_getc = bdat_getc;
8b77d27a 729 receive_getbuf = bdat_getbuf; /* r~getbuf is never actually used */
7e3ce68e 730 receive_ungetc = bdat_ungetc;
bd8fbe36 731#ifndef DISABLE_DKIM
79de4f37 732 dkim_collect_input = dkim_save;
bd8fbe36 733#endif
7e3ce68e
JH
734 break; /* to top of main loop */
735 }
736 }
737 }
738}
739
0d81dabc
JH
740uschar *
741bdat_getbuf(unsigned * len)
742{
743uschar * buf;
744
745if (chunking_data_left <= 0)
746 { *len = 0; return NULL; }
747
748if (*len > chunking_data_left) *len = chunking_data_left;
749buf = lwr_receive_getbuf(len); /* Either smtp_getbuf or tls_getbuf */
750chunking_data_left -= *len;
751return buf;
752}
753
1ebe15c3 754void
45bd315d
JH
755bdat_flush_data(void)
756{
e99a3a6c 757while (chunking_data_left)
db57e575 758 {
e99a3a6c 759 unsigned n = chunking_data_left;
8b77d27a 760 if (!bdat_getbuf(&n)) break;
db57e575 761 }
45bd315d
JH
762
763receive_getc = lwr_receive_getc;
0d81dabc 764receive_getbuf = lwr_receive_getbuf;
45bd315d
JH
765receive_ungetc = lwr_receive_ungetc;
766
767if (chunking_state != CHUNKING_LAST)
bd8fbe36 768 {
45bd315d 769 chunking_state = CHUNKING_OFFERED;
bd8fbe36
JH
770 DEBUG(D_receive) debug_printf("chunking state %d\n", (int)chunking_state);
771 }
45bd315d
JH
772}
773
7e3ce68e
JH
774
775
776
059ec3d9
PH
777/*************************************************
778* SMTP version of ungetc() *
779*************************************************/
780
781/* Puts a character back in the input buffer. Only ever
782called once.
783
784Arguments:
785 ch the character
786
787Returns: the character
788*/
789
790int
791smtp_ungetc(int ch)
792{
7e3ce68e 793*--smtp_inptr = ch;
059ec3d9
PH
794return ch;
795}
796
797
7e3ce68e
JH
798int
799bdat_ungetc(int ch)
800{
801chunking_data_left++;
802return lwr_receive_ungetc(ch);
803}
804
059ec3d9
PH
805
806
807/*************************************************
808* SMTP version of feof() *
809*************************************************/
810
811/* Tests for a previous EOF
812
813Arguments: none
814Returns: non-zero if the eof flag is set
815*/
816
817int
818smtp_feof(void)
819{
820return smtp_had_eof;
821}
822
823
824
825
826/*************************************************
827* SMTP version of ferror() *
828*************************************************/
829
830/* Tests for a previous read error, and returns with errno
831restored to what it was when the error was detected.
832
833Arguments: none
834Returns: non-zero if the error flag is set
835*/
836
837int
838smtp_ferror(void)
839{
840errno = smtp_had_error;
841return smtp_had_error;
842}
843
844
845
58eb016e
PH
846/*************************************************
847* Test for characters in the SMTP buffer *
848*************************************************/
849
850/* Used at the end of a message
851
852Arguments: none
853Returns: TRUE/FALSE
854*/
855
856BOOL
857smtp_buffered(void)
858{
859return smtp_inptr < smtp_inend;
860}
861
862
059ec3d9
PH
863
864/*************************************************
865* Write formatted string to SMTP channel *
866*************************************************/
867
868/* This is a separate function so that we don't have to repeat everything for
869TLS support or debugging. It is global so that the daemon and the
870authentication functions can use it. It does not return any error indication,
871because major problems such as dropped connections won't show up till an output
872flush for non-TLS connections. The smtp_fflush() function is available for
873checking that: for convenience, TLS output errors are remembered here so that
874they are also picked up later by smtp_fflush().
875
876Arguments:
877 format format string
925ac8e4 878 more further data expected
059ec3d9
PH
879 ... optional arguments
880
881Returns: nothing
882*/
883
884void
925ac8e4 885smtp_printf(const char *format, BOOL more, ...)
059ec3d9
PH
886{
887va_list ap;
888
925ac8e4
JH
889va_start(ap, more);
890smtp_vprintf(format, more, ap);
ce552449
NM
891va_end(ap);
892}
893
894/* This is split off so that verify.c:respond_printf() can, in effect, call
895smtp_printf(), bearing in mind that in C a vararg function can't directly
fb08281f 896call another vararg function, only a function which accepts a va_list. */
ce552449
NM
897
898void
925ac8e4 899smtp_vprintf(const char *format, BOOL more, va_list ap)
ce552449 900{
fb08281f
DW
901BOOL yield;
902
903yield = string_vformat(big_buffer, big_buffer_size, format, ap);
ce552449 904
059ec3d9
PH
905DEBUG(D_receive)
906 {
fb08281f
DW
907 void *reset_point = store_get(0);
908 uschar *msg_copy, *cr, *end;
909 msg_copy = string_copy(big_buffer);
910 end = msg_copy + Ustrlen(msg_copy);
911 while ((cr = Ustrchr(msg_copy, '\r')) != NULL) /* lose CRs */
912 memmove(cr, cr + 1, (end--) - cr);
913 debug_printf("SMTP>> %s", msg_copy);
914 store_reset(reset_point);
059ec3d9
PH
915 }
916
fb08281f 917if (!yield)
2679d413
PH
918 {
919 log_write(0, LOG_MAIN|LOG_PANIC, "string too large in smtp_printf()");
920 smtp_closedown(US"Unexpected error");
9bfb7e1b 921 exim_exit(EXIT_FAILURE, NULL);
2679d413 922 }
2679d413
PH
923
924/* If this is the first output for a (non-batch) RCPT command, see if all RCPTs
925have had the same. Note: this code is also present in smtp_respond(). It would
926be tidier to have it only in one place, but when it was added, it was easier to
927do it that way, so as not to have to mess with the code for the RCPT command,
928which sometimes uses smtp_printf() and sometimes smtp_respond(). */
929
88752192 930if (fl.rcpt_in_progress)
2679d413
PH
931 {
932 if (rcpt_smtp_response == NULL)
933 rcpt_smtp_response = string_copy(big_buffer);
88752192 934 else if (fl.rcpt_smtp_response_same &&
2679d413 935 Ustrcmp(rcpt_smtp_response, big_buffer) != 0)
88752192
JH
936 fl.rcpt_smtp_response_same = FALSE;
937 fl.rcpt_in_progress = FALSE;
2679d413 938 }
059ec3d9 939
2679d413 940/* Now write the string */
059ec3d9
PH
941
942#ifdef SUPPORT_TLS
74f1a423 943if (tls_in.active.sock >= 0)
059ec3d9 944 {
74f1a423 945 if (tls_write(NULL, big_buffer, Ustrlen(big_buffer), more) < 0)
817d9f57 946 smtp_write_error = -1;
059ec3d9
PH
947 }
948else
949#endif
950
2679d413 951if (fprintf(smtp_out, "%s", big_buffer) < 0) smtp_write_error = -1;
059ec3d9
PH
952}
953
954
955
956/*************************************************
957* Flush SMTP out and check for error *
958*************************************************/
959
960/* This function isn't currently used within Exim (it detects errors when it
961tries to read the next SMTP input), but is available for use in local_scan().
962For non-TLS connections, it flushes the output and checks for errors. For
963TLS-connections, it checks for a previously-detected TLS write error.
964
965Arguments: none
966Returns: 0 for no error; -1 after an error
967*/
968
969int
970smtp_fflush(void)
971{
74f1a423 972if (tls_in.active.sock < 0 && fflush(smtp_out) != 0) smtp_write_error = -1;
059ec3d9
PH
973return smtp_write_error;
974}
975
976
977
978/*************************************************
979* SMTP command read timeout *
980*************************************************/
981
982/* Signal handler for timing out incoming SMTP commands. This attempts to
983finish off tidily.
984
985Argument: signal number (SIGALRM)
986Returns: nothing
987*/
988
989static void
990command_timeout_handler(int sig)
991{
9723f966 992had_command_timeout = sig;
059ec3d9
PH
993}
994
995
996
997/*************************************************
998* SIGTERM received *
999*************************************************/
1000
1001/* Signal handler for handling SIGTERM. Again, try to finish tidily.
1002
1003Argument: signal number (SIGTERM)
1004Returns: nothing
1005*/
1006
1007static void
1008command_sigterm_handler(int sig)
1009{
9723f966 1010had_command_sigterm = sig;
059ec3d9
PH
1011}
1012
1013
1014
a14e5636 1015
cee5f132 1016#ifdef SUPPORT_PROXY
a3c86431 1017/*************************************************
a3bddaa8
TL
1018* Restore socket timeout to previous value *
1019*************************************************/
1020/* If the previous value was successfully retrieved, restore
1021it before returning control to the non-proxy routines
1022
1023Arguments: fd - File descriptor for input
1024 get_ok - Successfully retrieved previous values
1025 tvtmp - Time struct with previous values
1026 vslen - Length of time struct
1027Returns: none
1028*/
1029static void
f267271d 1030restore_socket_timeout(int fd, int get_ok, struct timeval * tvtmp, socklen_t vslen)
a3bddaa8
TL
1031{
1032if (get_ok == 0)
f267271d 1033 (void) setsockopt(fd, SOL_SOCKET, SO_RCVTIMEO, CS tvtmp, vslen);
a3bddaa8
TL
1034}
1035
1036/*************************************************
a3c86431
TL
1037* Check if host is required proxy host *
1038*************************************************/
1039/* The function determines if inbound host will be a regular smtp host
1811cb4c
JH
1040or if it is configured that it must use Proxy Protocol. A local
1041connection cannot.
a3c86431
TL
1042
1043Arguments: none
1044Returns: bool
1045*/
1046
1047static BOOL
1048check_proxy_protocol_host()
1049{
1050int rc;
a3c86431 1051
1811cb4c
JH
1052if ( sender_host_address
1053 && (rc = verify_check_this_host(CUSS &hosts_proxy, NULL, NULL,
1054 sender_host_address, NULL)) == OK)
a3c86431
TL
1055 {
1056 DEBUG(D_receive)
1057 debug_printf("Detected proxy protocol configured host\n");
1058 proxy_session = TRUE;
1059 }
1060return proxy_session;
1061}
1062
1063
1064/*************************************************
3f251b3c
PP
1065* Read data until newline or end of buffer *
1066*************************************************/
1067/* While SMTP is server-speaks-first, TLS is client-speaks-first, so we can't
1068read an entire buffer and assume there will be nothing past a proxy protocol
1069header. Our approach normally is to use stdio, but again that relies upon
1070"STARTTLS\r\n" and a server response before the client starts TLS handshake, or
1071reading _nothing_ before client TLS handshake. So we don't want to use the
1072usual buffering reads which may read enough to block TLS starting.
1073
1074So unfortunately we're down to "read one byte at a time, with a syscall each,
1075and expect a little overhead", for all proxy-opened connections which are v1,
1076just to handle the TLS-on-connect case. Since SSL functions wrap the
1077underlying fd, we can't assume that we can feed them any already-read content.
1078
1079We need to know where to read to, the max capacity, and we'll read until we
1080get a CR and one more character. Let the caller scream if it's CR+!LF.
1081
1082Return the amount read.
1083*/
1084
1085static int
da88acae 1086swallow_until_crlf(int fd, uschar *base, int already, int capacity)
3f251b3c 1087{
2c0f3ea1
JH
1088uschar *to = base + already;
1089uschar *cr;
1090int have = 0;
1091int ret;
1092int last = 0;
1093
1094/* For "PROXY UNKNOWN\r\n" we, at time of writing, expect to have read
1095up through the \r; for the _normal_ case, we haven't yet seen the \r. */
da88acae 1096
2c0f3ea1
JH
1097cr = memchr(base, '\r', already);
1098if (cr != NULL)
1099 {
1100 if ((cr - base) < already - 1)
da88acae 1101 {
2c0f3ea1
JH
1102 /* \r and presumed \n already within what we have; probably not
1103 actually proxy protocol, but abort cleanly. */
1104 return 0;
da88acae 1105 }
2c0f3ea1
JH
1106 /* \r is last character read, just need one more. */
1107 last = 1;
1108 }
1109
1110while (capacity > 0)
1111 {
1112 do { ret = recv(fd, to, 1, 0); } while (ret == -1 && errno == EINTR);
1113 if (ret == -1)
1114 return -1;
1115 have++;
1116 if (last)
1117 return have;
1118 if (*to == '\r')
1119 last = 1;
1120 capacity--;
1121 to++;
1122 }
1123
1124/* reached end without having room for a final newline, abort */
1125errno = EOVERFLOW;
1126return -1;
3f251b3c
PP
1127}
1128
1129/*************************************************
a3c86431
TL
1130* Setup host for proxy protocol *
1131*************************************************/
1132/* The function configures the connection based on a header from the
1133inbound host to use Proxy Protocol. The specification is very exact
1134so exit with an error if do not find the exact required pieces. This
1135includes an incorrect number of spaces separating args.
1136
1137Arguments: none
f267271d 1138Returns: Boolean success
a3c86431
TL
1139*/
1140
1811cb4c 1141static void
a3c86431
TL
1142setup_proxy_protocol_host()
1143{
1144union {
1145 struct {
1146 uschar line[108];
1147 } v1;
1148 struct {
1149 uschar sig[12];
36719342
TL
1150 uint8_t ver_cmd;
1151 uint8_t fam;
1152 uint16_t len;
a3c86431
TL
1153 union {
1154 struct { /* TCP/UDP over IPv4, len = 12 */
1155 uint32_t src_addr;
1156 uint32_t dst_addr;
1157 uint16_t src_port;
1158 uint16_t dst_port;
1159 } ip4;
1160 struct { /* TCP/UDP over IPv6, len = 36 */
1161 uint8_t src_addr[16];
1162 uint8_t dst_addr[16];
1163 uint16_t src_port;
1164 uint16_t dst_port;
1165 } ip6;
1166 struct { /* AF_UNIX sockets, len = 216 */
1167 uschar src_addr[108];
1168 uschar dst_addr[108];
1169 } unx;
1170 } addr;
1171 } v2;
1172} hdr;
1173
eb57651e
TL
1174/* Temp variables used in PPv2 address:port parsing */
1175uint16_t tmpport;
1176char tmpip[INET_ADDRSTRLEN];
1177struct sockaddr_in tmpaddr;
1178char tmpip6[INET6_ADDRSTRLEN];
1179struct sockaddr_in6 tmpaddr6;
1180
da88acae
PP
1181/* We can't read "all data until end" because while SMTP is
1182server-speaks-first, the TLS handshake is client-speaks-first, so for
1183TLS-on-connect ports the proxy protocol header will usually be immediately
1184followed by a TLS handshake, and with N TLS libraries, we can't reliably
1185reinject data for reading by those. So instead we first read "enough to be
1186safely read within the header, and figure out how much more to read".
1187For v1 we will later read to the end-of-line, for v2 we will read based upon
1188the stated length.
1189
1190The v2 sig is 12 octets, and another 4 gets us the length, so we know how much
1191data is needed total. For v1, where the line looks like:
1192PROXY TCPn L3src L3dest SrcPort DestPort \r\n
1193
1194However, for v1 there's also `PROXY UNKNOWN\r\n` which is only 15 octets.
1195We seem to support that. So, if we read 14 octets then we can tell if we're
1196v2 or v1. If we're v1, we can continue reading as normal.
1197
1198If we're v2, we can't slurp up the entire header. We need the length in the
119915th & 16th octets, then to read everything after that.
1200
1201So to safely handle v1 and v2, with client-sent-first supported correctly,
1202we have to do a minimum of 3 read calls, not 1. Eww.
1203*/
1204
1205#define PROXY_INITIAL_READ 14
1206#define PROXY_V2_HEADER_SIZE 16
1207#if PROXY_INITIAL_READ > PROXY_V2_HEADER_SIZE
1208# error Code bug in sizes of data to read for proxy usage
1209#endif
1210
eb57651e 1211int get_ok = 0;
f267271d
JH
1212int size, ret;
1213int fd = fileno(smtp_in);
36719342 1214const char v2sig[12] = "\x0D\x0A\x0D\x0A\x00\x0D\x0A\x51\x55\x49\x54\x0A";
9e7e0f6a 1215uschar * iptype; /* To display debug info */
a3c86431 1216struct timeval tv;
a3bddaa8 1217struct timeval tvtmp;
f267271d 1218socklen_t vslen = sizeof(struct timeval);
1811cb4c 1219BOOL yield = FALSE;
a3c86431 1220
a3bddaa8 1221/* Save current socket timeout values */
f267271d 1222get_ok = getsockopt(fd, SOL_SOCKET, SO_RCVTIMEO, CS &tvtmp, &vslen);
a3bddaa8 1223
a3c86431
TL
1224/* Proxy Protocol host must send header within a short time
1225(default 3 seconds) or it's considered invalid */
1226tv.tv_sec = PROXY_NEGOTIATION_TIMEOUT_SEC;
1227tv.tv_usec = PROXY_NEGOTIATION_TIMEOUT_USEC;
f267271d 1228if (setsockopt(fd, SOL_SOCKET, SO_RCVTIMEO, CS &tv, sizeof(tv)) < 0)
1811cb4c 1229 goto bad;
a3bddaa8 1230
a3c86431
TL
1231do
1232 {
eb57651e 1233 /* The inbound host was declared to be a Proxy Protocol host, so
2c0f3ea1
JH
1234 don't do a PEEK into the data, actually slurp up enough to be
1235 "safe". Can't take it all because TLS-on-connect clients follow
1236 immediately with TLS handshake. */
3f251b3c 1237 ret = recv(fd, &hdr, PROXY_INITIAL_READ, 0);
a3c86431
TL
1238 }
1239 while (ret == -1 && errno == EINTR);
1240
1241if (ret == -1)
f267271d 1242 goto proxyfail;
a3c86431 1243
da88acae
PP
1244/* For v2, handle reading the length, and then the rest. */
1245if ((ret == PROXY_INITIAL_READ) && (memcmp(&hdr.v2, v2sig, sizeof(v2sig)) == 0))
a3c86431 1246 {
da88acae
PP
1247 int retmore;
1248 uint8_t ver;
1249
1250 /* First get the length fields. */
1251 do
1252 {
1253 retmore = recv(fd, (uschar*)&hdr + ret, PROXY_V2_HEADER_SIZE - PROXY_INITIAL_READ, 0);
1254 } while (retmore == -1 && errno == EINTR);
1255 if (retmore == -1)
3f251b3c 1256 goto proxyfail;
da88acae 1257 ret += retmore;
3f251b3c
PP
1258
1259 ver = (hdr.v2.ver_cmd & 0xf0) >> 4;
36719342
TL
1260
1261 /* May 2014: haproxy combined the version and command into one byte to
2c0f3ea1
JH
1262 allow two full bytes for the length field in order to proxy SSL
1263 connections. SSL Proxy is not supported in this version of Exim, but
1264 must still separate values here. */
36719342
TL
1265
1266 if (ver != 0x02)
1267 {
1268 DEBUG(D_receive) debug_printf("Invalid Proxy Protocol version: %d\n", ver);
1269 goto proxyfail;
1270 }
da88acae 1271
36719342 1272 /* The v2 header will always be 16 bytes per the spec. */
5d036699 1273 size = 16 + ntohs(hdr.v2.len);
da88acae
PP
1274 DEBUG(D_receive) debug_printf("Detected PROXYv2 header, size %d (limit %d)\n",
1275 size, (int)sizeof(hdr));
1276
1277 /* We should now have 16 octets (PROXY_V2_HEADER_SIZE), and we know the total
1278 amount that we need. Double-check that the size is not unreasonable, then
1279 get the rest. */
1280 if (size > sizeof(hdr))
a3c86431 1281 {
da88acae 1282 DEBUG(D_receive) debug_printf("PROXYv2 header size unreasonably large; security attack?\n");
a3c86431
TL
1283 goto proxyfail;
1284 }
da88acae
PP
1285
1286 do
1287 {
1288 do
1289 {
1290 retmore = recv(fd, (uschar*)&hdr + ret, size-ret, 0);
1291 } while (retmore == -1 && errno == EINTR);
1292 if (retmore == -1)
1293 goto proxyfail;
1294 ret += retmore;
1295 DEBUG(D_receive) debug_printf("PROXYv2: have %d/%d required octets\n", ret, size);
1296 } while (ret < size);
1297
1298 } /* end scope for getting rest of data for v2 */
1299
1300/* At this point: if PROXYv2, we've read the exact size required for all data;
1301if PROXYv1 then we've read "less than required for any valid line" and should
1302read the rest". */
1303
1304if (ret >= 16 && memcmp(&hdr.v2, v2sig, 12) == 0)
1305 {
1306 uint8_t cmd = (hdr.v2.ver_cmd & 0x0f);
1307
36719342 1308 switch (cmd)
a3c86431
TL
1309 {
1310 case 0x01: /* PROXY command */
1311 switch (hdr.v2.fam)
1312 {
eb57651e
TL
1313 case 0x11: /* TCPv4 address type */
1314 iptype = US"IPv4";
1315 tmpaddr.sin_addr.s_addr = hdr.v2.addr.ip4.src_addr;
5d036699
JH
1316 inet_ntop(AF_INET, &tmpaddr.sin_addr, CS &tmpip, sizeof(tmpip));
1317 if (!string_is_ip_address(US tmpip, NULL))
eb57651e
TL
1318 {
1319 DEBUG(D_receive) debug_printf("Invalid %s source IP\n", iptype);
f267271d 1320 goto proxyfail;
eb57651e 1321 }
e6d2a989 1322 proxy_local_address = sender_host_address;
eb57651e
TL
1323 sender_host_address = string_copy(US tmpip);
1324 tmpport = ntohs(hdr.v2.addr.ip4.src_port);
e6d2a989 1325 proxy_local_port = sender_host_port;
eb57651e
TL
1326 sender_host_port = tmpport;
1327 /* Save dest ip/port */
1328 tmpaddr.sin_addr.s_addr = hdr.v2.addr.ip4.dst_addr;
5d036699
JH
1329 inet_ntop(AF_INET, &tmpaddr.sin_addr, CS &tmpip, sizeof(tmpip));
1330 if (!string_is_ip_address(US tmpip, NULL))
eb57651e
TL
1331 {
1332 DEBUG(D_receive) debug_printf("Invalid %s dest port\n", iptype);
f267271d 1333 goto proxyfail;
eb57651e 1334 }
7a2fa0bc 1335 proxy_external_address = string_copy(US tmpip);
eb57651e 1336 tmpport = ntohs(hdr.v2.addr.ip4.dst_port);
7a2fa0bc 1337 proxy_external_port = tmpport;
a3c86431 1338 goto done;
eb57651e
TL
1339 case 0x21: /* TCPv6 address type */
1340 iptype = US"IPv6";
1341 memmove(tmpaddr6.sin6_addr.s6_addr, hdr.v2.addr.ip6.src_addr, 16);
5d036699
JH
1342 inet_ntop(AF_INET6, &tmpaddr6.sin6_addr, CS &tmpip6, sizeof(tmpip6));
1343 if (!string_is_ip_address(US tmpip6, NULL))
eb57651e
TL
1344 {
1345 DEBUG(D_receive) debug_printf("Invalid %s source IP\n", iptype);
f267271d 1346 goto proxyfail;
eb57651e 1347 }
e6d2a989 1348 proxy_local_address = sender_host_address;
eb57651e
TL
1349 sender_host_address = string_copy(US tmpip6);
1350 tmpport = ntohs(hdr.v2.addr.ip6.src_port);
e6d2a989 1351 proxy_local_port = sender_host_port;
eb57651e
TL
1352 sender_host_port = tmpport;
1353 /* Save dest ip/port */
1354 memmove(tmpaddr6.sin6_addr.s6_addr, hdr.v2.addr.ip6.dst_addr, 16);
5d036699
JH
1355 inet_ntop(AF_INET6, &tmpaddr6.sin6_addr, CS &tmpip6, sizeof(tmpip6));
1356 if (!string_is_ip_address(US tmpip6, NULL))
eb57651e
TL
1357 {
1358 DEBUG(D_receive) debug_printf("Invalid %s dest port\n", iptype);
f267271d 1359 goto proxyfail;
eb57651e 1360 }
7a2fa0bc 1361 proxy_external_address = string_copy(US tmpip6);
eb57651e 1362 tmpport = ntohs(hdr.v2.addr.ip6.dst_port);
7a2fa0bc 1363 proxy_external_port = tmpport;
a3c86431 1364 goto done;
eb57651e
TL
1365 default:
1366 DEBUG(D_receive)
1367 debug_printf("Unsupported PROXYv2 connection type: 0x%02x\n",
1368 hdr.v2.fam);
1369 goto proxyfail;
a3c86431
TL
1370 }
1371 /* Unsupported protocol, keep local connection address */
1372 break;
1373 case 0x00: /* LOCAL command */
1374 /* Keep local connection address for LOCAL */
9e7e0f6a 1375 iptype = US"local";
a3c86431
TL
1376 break;
1377 default:
eb57651e 1378 DEBUG(D_receive)
36719342 1379 debug_printf("Unsupported PROXYv2 command: 0x%x\n", cmd);
a3c86431
TL
1380 goto proxyfail;
1381 }
1382 }
5d036699 1383else if (ret >= 8 && memcmp(hdr.v1.line, "PROXY", 5) == 0)
a3c86431 1384 {
3f251b3c
PP
1385 uschar *p;
1386 uschar *end;
a3c86431
TL
1387 uschar *sp; /* Utility variables follow */
1388 int tmp_port;
3f251b3c 1389 int r2;
a3c86431
TL
1390 char *endc;
1391
3f251b3c 1392 /* get the rest of the line */
da88acae 1393 r2 = swallow_until_crlf(fd, (uschar*)&hdr, ret, sizeof(hdr)-ret);
3f251b3c
PP
1394 if (r2 == -1)
1395 goto proxyfail;
1396 ret += r2;
1397
1398 p = string_copy(hdr.v1.line);
1399 end = memchr(p, '\r', ret - 1);
1400
da88acae 1401 if (!end || (end == (uschar*)&hdr + ret) || end[1] != '\n')
a3c86431
TL
1402 {
1403 DEBUG(D_receive) debug_printf("Partial or invalid PROXY header\n");
1404 goto proxyfail;
1405 }
1406 *end = '\0'; /* Terminate the string */
a5d4db40 1407 size = end + 2 - p; /* Skip header + CRLF */
a3c86431 1408 DEBUG(D_receive) debug_printf("Detected PROXYv1 header\n");
3f251b3c 1409 DEBUG(D_receive) debug_printf("Bytes read not within PROXY header: %d\n", ret - size);
a3c86431 1410 /* Step through the string looking for the required fields. Ensure
2c0f3ea1 1411 strict adherence to required formatting, exit for any error. */
a3c86431
TL
1412 p += 5;
1413 if (!isspace(*(p++)))
1414 {
1415 DEBUG(D_receive) debug_printf("Missing space after PROXY command\n");
1416 goto proxyfail;
1417 }
1418 if (!Ustrncmp(p, CCS"TCP4", 4))
1419 iptype = US"IPv4";
1420 else if (!Ustrncmp(p,CCS"TCP6", 4))
1421 iptype = US"IPv6";
1422 else if (!Ustrncmp(p,CCS"UNKNOWN", 7))
1423 {
1424 iptype = US"Unknown";
1425 goto done;
1426 }
1427 else
1428 {
1429 DEBUG(D_receive) debug_printf("Invalid TCP type\n");
1430 goto proxyfail;
1431 }
1432
1433 p += Ustrlen(iptype);
1434 if (!isspace(*(p++)))
1435 {
1436 DEBUG(D_receive) debug_printf("Missing space after TCP4/6 command\n");
1437 goto proxyfail;
1438 }
1439 /* Find the end of the arg */
1440 if ((sp = Ustrchr(p, ' ')) == NULL)
1441 {
1442 DEBUG(D_receive)
1443 debug_printf("Did not find proxied src %s\n", iptype);
1444 goto proxyfail;
1445 }
1446 *sp = '\0';
5d036699 1447 if(!string_is_ip_address(p, NULL))
a3c86431
TL
1448 {
1449 DEBUG(D_receive)
1450 debug_printf("Proxied src arg is not an %s address\n", iptype);
1451 goto proxyfail;
1452 }
e6d2a989 1453 proxy_local_address = sender_host_address;
a3c86431
TL
1454 sender_host_address = p;
1455 p = sp + 1;
1456 if ((sp = Ustrchr(p, ' ')) == NULL)
1457 {
1458 DEBUG(D_receive)
1459 debug_printf("Did not find proxy dest %s\n", iptype);
1460 goto proxyfail;
1461 }
1462 *sp = '\0';
5d036699 1463 if(!string_is_ip_address(p, NULL))
a3c86431
TL
1464 {
1465 DEBUG(D_receive)
1466 debug_printf("Proxy dest arg is not an %s address\n", iptype);
1467 goto proxyfail;
1468 }
7a2fa0bc 1469 proxy_external_address = p;
a3c86431
TL
1470 p = sp + 1;
1471 if ((sp = Ustrchr(p, ' ')) == NULL)
1472 {
1473 DEBUG(D_receive) debug_printf("Did not find proxied src port\n");
1474 goto proxyfail;
1475 }
1476 *sp = '\0';
5d036699 1477 tmp_port = strtol(CCS p, &endc, 10);
a3c86431
TL
1478 if (*endc || tmp_port == 0)
1479 {
1480 DEBUG(D_receive)
1481 debug_printf("Proxied src port '%s' not an integer\n", p);
1482 goto proxyfail;
1483 }
e6d2a989 1484 proxy_local_port = sender_host_port;
a3c86431
TL
1485 sender_host_port = tmp_port;
1486 p = sp + 1;
1487 if ((sp = Ustrchr(p, '\0')) == NULL)
1488 {
1489 DEBUG(D_receive) debug_printf("Did not find proxy dest port\n");
1490 goto proxyfail;
1491 }
5d036699 1492 tmp_port = strtol(CCS p, &endc, 10);
a3c86431
TL
1493 if (*endc || tmp_port == 0)
1494 {
1495 DEBUG(D_receive)
1496 debug_printf("Proxy dest port '%s' not an integer\n", p);
1497 goto proxyfail;
1498 }
7a2fa0bc 1499 proxy_external_port = tmp_port;
a3c86431 1500 /* Already checked for /r /n above. Good V1 header received. */
a3c86431
TL
1501 }
1502else
1503 {
1504 /* Wrong protocol */
eb57651e 1505 DEBUG(D_receive) debug_printf("Invalid proxy protocol version negotiation\n");
da88acae 1506 (void) swallow_until_crlf(fd, (uschar*)&hdr, ret, sizeof(hdr)-ret);
a3c86431
TL
1507 goto proxyfail;
1508 }
1509
1811cb4c
JH
1510done:
1511 DEBUG(D_receive)
1512 debug_printf("Valid %s sender from Proxy Protocol header\n", iptype);
1513 yield = proxy_session;
1514
1515/* Don't flush any potential buffer contents. Any input on proxyfail
1516should cause a synchronization failure */
1517
a3c86431 1518proxyfail:
1811cb4c 1519 restore_socket_timeout(fd, get_ok, &tvtmp, vslen);
a3c86431 1520
1811cb4c
JH
1521bad:
1522 if (yield)
1523 {
1524 sender_host_name = NULL;
1525 (void) host_name_lookup();
1526 host_build_sender_fullhost();
1527 }
1528 else
1529 {
8768d548 1530 f.proxy_session_failed = TRUE;
1811cb4c
JH
1531 DEBUG(D_receive)
1532 debug_printf("Failure to extract proxied host, only QUIT allowed\n");
1533 }
1534
1535return;
a3c86431
TL
1536}
1537#endif
1538
059ec3d9
PH
1539/*************************************************
1540* Read one command line *
1541*************************************************/
1542
1543/* Strictly, SMTP commands coming over the net are supposed to end with CRLF.
1544There are sites that don't do this, and in any case internal SMTP probably
1545should check only for LF. Consequently, we check here for LF only. The line
1546ends up with [CR]LF removed from its end. If we get an overlong line, treat as
3ee512ff
PH
1547an unknown command. The command is read into the global smtp_cmd_buffer so that
1548it is available via $smtp_command.
059ec3d9
PH
1549
1550The character reading routine sets up a timeout for each block actually read
1551from the input (which may contain more than one command). We set up a special
1552signal handler that closes down the session on a timeout. Control does not
1553return when it runs.
1554
1555Arguments:
bd8fbe36
JH
1556 check_sync if TRUE, check synchronization rules if global option is TRUE
1557 buffer_lim maximum to buffer in lower layer
059ec3d9
PH
1558
1559Returns: a code identifying the command (enumerated above)
1560*/
1561
1562static int
bd8fbe36 1563smtp_read_command(BOOL check_sync, unsigned buffer_lim)
059ec3d9
PH
1564{
1565int c;
1566int ptr = 0;
1567smtp_cmd_list *p;
1568BOOL hadnull = FALSE;
1569
9723f966 1570had_command_timeout = 0;
059ec3d9
PH
1571os_non_restarting_signal(SIGALRM, command_timeout_handler);
1572
bd8fbe36 1573while ((c = (receive_getc)(buffer_lim)) != '\n' && c != EOF)
059ec3d9 1574 {
bd8fbe36 1575 if (ptr >= SMTP_CMD_BUFFER_SIZE)
059ec3d9
PH
1576 {
1577 os_non_restarting_signal(SIGALRM, sigalrm_handler);
1578 return OTHER_CMD;
1579 }
1580 if (c == 0)
1581 {
1582 hadnull = TRUE;
1583 c = '?';
1584 }
3ee512ff 1585 smtp_cmd_buffer[ptr++] = c;
059ec3d9
PH
1586 }
1587
1588receive_linecount++; /* For BSMTP errors */
1589os_non_restarting_signal(SIGALRM, sigalrm_handler);
1590
1591/* If hit end of file, return pseudo EOF command. Whether we have a
1592part-line already read doesn't matter, since this is an error state. */
1593
1594if (c == EOF) return EOF_CMD;
1595
1596/* Remove any CR and white space at the end of the line, and terminate the
1597string. */
1598
3ee512ff
PH
1599while (ptr > 0 && isspace(smtp_cmd_buffer[ptr-1])) ptr--;
1600smtp_cmd_buffer[ptr] = 0;
059ec3d9 1601
3ee512ff 1602DEBUG(D_receive) debug_printf("SMTP<< %s\n", smtp_cmd_buffer);
059ec3d9
PH
1603
1604/* NULLs are not allowed in SMTP commands */
1605
1606if (hadnull) return BADCHAR_CMD;
1607
1608/* Scan command list and return identity, having set the data pointer
1609to the start of the actual data characters. Check for SMTP synchronization
1610if required. */
1611
1612for (p = cmd_list; p < cmd_list_end; p++)
1613 {
1811cb4c 1614#ifdef SUPPORT_PROXY
a3c86431 1615 /* Only allow QUIT command if Proxy Protocol parsing failed */
8768d548 1616 if (proxy_session && f.proxy_session_failed && p->cmd != QUIT_CMD)
1811cb4c
JH
1617 continue;
1618#endif
2f460950
JH
1619 if ( p->len
1620 && strncmpic(smtp_cmd_buffer, US p->name, p->len) == 0
1621 && ( smtp_cmd_buffer[p->len-1] == ':' /* "mail from:" or "rcpt to:" */
1622 || smtp_cmd_buffer[p->len] == 0
1623 || smtp_cmd_buffer[p->len] == ' '
1624 ) )
059ec3d9
PH
1625 {
1626 if (smtp_inptr < smtp_inend && /* Outstanding input */
1627 p->cmd < sync_cmd_limit && /* Command should sync */
1628 check_sync && /* Local flag set */
1629 smtp_enforce_sync && /* Global flag set */
1630 sender_host_address != NULL && /* Not local input */
8768d548 1631 !f.sender_host_notsocket) /* Really is a socket */
059ec3d9
PH
1632 return BADSYN_CMD;
1633
ca86f471
PH
1634 /* The variables $smtp_command and $smtp_command_argument point into the
1635 unmodified input buffer. A copy of the latter is taken for actual
1636 processing, so that it can be chopped up into separate parts if necessary,
1637 for example, when processing a MAIL command options such as SIZE that can
1638 follow the sender address. */
059ec3d9 1639
3ee512ff 1640 smtp_cmd_argument = smtp_cmd_buffer + p->len;
ca86f471
PH
1641 while (isspace(*smtp_cmd_argument)) smtp_cmd_argument++;
1642 Ustrcpy(smtp_data_buffer, smtp_cmd_argument);
1643 smtp_cmd_data = smtp_data_buffer;
059ec3d9
PH
1644
1645 /* Count non-mail commands from those hosts that are controlled in this
1646 way. The default is all hosts. We don't waste effort checking the list
1647 until we get a non-mail command, but then cache the result to save checking
1648 again. If there's a DEFER while checking the host, assume it's in the list.
1649
1650 Note that one instance of RSET, EHLO/HELO, and STARTTLS is allowed at the
1651 start of each incoming message by fiddling with the value in the table. */
1652
1653 if (!p->is_mail_cmd)
1654 {
1655 if (count_nonmail == TRUE_UNSET) count_nonmail =
1656 verify_check_host(&smtp_accept_max_nonmail_hosts) != FAIL;
1657 if (count_nonmail && ++nonmail_command_count > smtp_accept_max_nonmail)
1658 return TOO_MANY_NONMAIL_CMD;
1659 }
1660
ca86f471
PH
1661 /* If there is data for a command that does not expect it, generate the
1662 error here. */
059ec3d9 1663
ca86f471 1664 return (p->has_arg || *smtp_cmd_data == 0)? p->cmd : BADARG_CMD;
059ec3d9
PH
1665 }
1666 }
1667
cee5f132 1668#ifdef SUPPORT_PROXY
a3c86431 1669/* Only allow QUIT command if Proxy Protocol parsing failed */
8768d548 1670if (proxy_session && f.proxy_session_failed)
a3c86431
TL
1671 return PROXY_FAIL_IGNORE_CMD;
1672#endif
1673
059ec3d9
PH
1674/* Enforce synchronization for unknown commands */
1675
ecce6d9a
JH
1676if ( smtp_inptr < smtp_inend /* Outstanding input */
1677 && check_sync /* Local flag set */
1678 && smtp_enforce_sync /* Global flag set */
1679 && sender_host_address /* Not local input */
8768d548 1680 && !f.sender_host_notsocket) /* Really is a socket */
059ec3d9
PH
1681 return BADSYN_CMD;
1682
1683return OTHER_CMD;
1684}
1685
1686
1687
1688/*************************************************
1689* Forced closedown of call *
1690*************************************************/
1691
1692/* This function is called from log.c when Exim is dying because of a serious
1693disaster, and also from some other places. If an incoming non-batched SMTP
1694channel is open, it swallows the rest of the incoming message if in the DATA
1695phase, sends the reply string, and gives an error to all subsequent commands
1696except QUIT. The existence of an SMTP call is detected by the non-NULLness of
1697smtp_in.
1698
8f128379
PH
1699Arguments:
1700 message SMTP reply string to send, excluding the code
1701
059ec3d9
PH
1702Returns: nothing
1703*/
1704
1705void
1706smtp_closedown(uschar *message)
1707{
db57e575 1708if (!smtp_in || smtp_batched_input) return;
059ec3d9 1709receive_swallow_smtp();
925ac8e4 1710smtp_printf("421 %s\r\n", FALSE, message);
059ec3d9 1711
bd8fbe36 1712for (;;) switch(smtp_read_command(FALSE, GETC_BUFFER_UNLIMITED))
059ec3d9 1713 {
60d10ce7 1714 case EOF_CMD:
db57e575 1715 return;
059ec3d9 1716
60d10ce7 1717 case QUIT_CMD:
db57e575
JH
1718 smtp_printf("221 %s closing connection\r\n", FALSE, smtp_active_hostname);
1719 mac_smtp_fflush();
1720 return;
059ec3d9 1721
60d10ce7 1722 case RSET_CMD:
db57e575
JH
1723 smtp_printf("250 Reset OK\r\n", FALSE);
1724 break;
059ec3d9 1725
60d10ce7 1726 default:
db57e575
JH
1727 smtp_printf("421 %s\r\n", FALSE, message);
1728 break;
059ec3d9
PH
1729 }
1730}
1731
1732
1733
1734
1735/*************************************************
1736* Set up connection info for logging *
1737*************************************************/
1738
1739/* This function is called when logging information about an SMTP connection.
1740It sets up appropriate source information, depending on the type of connection.
dac79d3e
PH
1741If sender_fullhost is NULL, we are at a very early stage of the connection;
1742just use the IP address.
059ec3d9
PH
1743
1744Argument: none
1745Returns: a string describing the connection
1746*/
1747
1748uschar *
1749smtp_get_connection_info(void)
1750{
f5d25c2b
JH
1751const uschar * hostname = sender_fullhost
1752 ? sender_fullhost : sender_host_address;
dac79d3e 1753
059ec3d9 1754if (host_checking)
dac79d3e 1755 return string_sprintf("SMTP connection from %s", hostname);
059ec3d9 1756
8768d548 1757if (f.sender_host_unknown || f.sender_host_notsocket)
059ec3d9
PH
1758 return string_sprintf("SMTP connection from %s", sender_ident);
1759
8768d548 1760if (f.is_inetd)
dac79d3e 1761 return string_sprintf("SMTP connection from %s (via inetd)", hostname);
059ec3d9 1762
6c6d6e48 1763if (LOGGING(incoming_interface) && interface_address != NULL)
dac79d3e 1764 return string_sprintf("SMTP connection from %s I=[%s]:%d", hostname,
059ec3d9
PH
1765 interface_address, interface_port);
1766
dac79d3e 1767return string_sprintf("SMTP connection from %s", hostname);
059ec3d9
PH
1768}
1769
1770
1771
e45a1c37 1772#ifdef SUPPORT_TLS
887291d2
JH
1773/* Append TLS-related information to a log line
1774
1775Arguments:
acec9514 1776 g String under construction: allocated string to extend, or NULL
887291d2
JH
1777
1778Returns: Allocated string or NULL
1779*/
acec9514
JH
1780static gstring *
1781s_tlslog(gstring * g)
e45a1c37 1782{
acec9514
JH
1783if (LOGGING(tls_cipher) && tls_in.cipher)
1784 g = string_append(g, 2, US" X=", tls_in.cipher);
1785if (LOGGING(tls_certificate_verified) && tls_in.cipher)
1786 g = string_append(g, 2, US" CV=", tls_in.certificate_verified? "yes":"no");
1787if (LOGGING(tls_peerdn) && tls_in.peerdn)
1788 g = string_append(g, 3, US" DN=\"", string_printing(tls_in.peerdn), US"\"");
1789if (LOGGING(tls_sni) && tls_in.sni)
1790 g = string_append(g, 3, US" SNI=\"", string_printing(tls_in.sni), US"\"");
1791return g;
e45a1c37
JH
1792}
1793#endif
1794
059ec3d9 1795/*************************************************
b4ed4da0
PH
1796* Log lack of MAIL if so configured *
1797*************************************************/
1798
1799/* This function is called when an SMTP session ends. If the log selector
1800smtp_no_mail is set, write a log line giving some details of what has happened
1801in the SMTP session.
1802
1803Arguments: none
1804Returns: nothing
1805*/
1806
1807void
1808smtp_log_no_mail(void)
1809{
acec9514
JH
1810int i;
1811uschar * sep, * s;
1812gstring * g = NULL;
b4ed4da0 1813
6c6d6e48 1814if (smtp_mailcmd_count > 0 || !LOGGING(smtp_no_mail))
b4ed4da0
PH
1815 return;
1816
db57e575 1817if (sender_host_authenticated)
b4ed4da0 1818 {
acec9514
JH
1819 g = string_append(g, 2, US" A=", sender_host_authenticated);
1820 if (authenticated_id) g = string_append(g, 2, US":", authenticated_id);
b4ed4da0
PH
1821 }
1822
1823#ifdef SUPPORT_TLS
acec9514 1824g = s_tlslog(g);
3f0945ff 1825#endif
b4ed4da0 1826
acec9514
JH
1827sep = smtp_connection_had[SMTP_HBUFF_SIZE-1] != SCH_NONE ? US" C=..." : US" C=";
1828
b4ed4da0 1829for (i = smtp_ch_index; i < SMTP_HBUFF_SIZE; i++)
b4ed4da0
PH
1830 if (smtp_connection_had[i] != SCH_NONE)
1831 {
acec9514 1832 g = string_append(g, 2, sep, smtp_names[smtp_connection_had[i]]);
b4ed4da0
PH
1833 sep = US",";
1834 }
b4ed4da0
PH
1835
1836for (i = 0; i < smtp_ch_index; i++)
1837 {
acec9514 1838 g = string_append(g, 2, sep, smtp_names[smtp_connection_had[i]]);
b4ed4da0
PH
1839 sep = US",";
1840 }
1841
acec9514
JH
1842if (!(s = string_from_gstring(g))) s = US"";
1843
a2673768 1844log_write(0, LOG_MAIN, "no MAIL in %sSMTP connection from %s D=%s%s",
8768d548 1845 f.tcp_in_fastopen ? US"TFO " : US"",
0f1a8658 1846 host_and_ident(FALSE), string_timesince(&smtp_connection_start), s);
b4ed4da0
PH
1847}
1848
1849
a09f2942
JH
1850/* Return list of recent smtp commands */
1851
1852uschar *
1853smtp_cmd_hist(void)
1854{
acec9514
JH
1855int i;
1856gstring * list = NULL;
1857uschar * s;
a09f2942
JH
1858
1859for (i = smtp_ch_index; i < SMTP_HBUFF_SIZE; i++)
1860 if (smtp_connection_had[i] != SCH_NONE)
acec9514
JH
1861 list = string_append_listele(list, ',', smtp_names[smtp_connection_had[i]]);
1862
a09f2942 1863for (i = 0; i < smtp_ch_index; i++)
acec9514
JH
1864 list = string_append_listele(list, ',', smtp_names[smtp_connection_had[i]]);
1865
1866s = string_from_gstring(list);
1867return s ? s : US"";
a09f2942
JH
1868}
1869
1870
1871
b4ed4da0
PH
1872
1873/*************************************************
059ec3d9
PH
1874* Check HELO line and set sender_helo_name *
1875*************************************************/
1876
1877/* Check the format of a HELO line. The data for HELO/EHLO is supposed to be
1878the domain name of the sending host, or an ip literal in square brackets. The
4c04137d 1879argument is placed in sender_helo_name, which is in malloc store, because it
059ec3d9
PH
1880must persist over multiple incoming messages. If helo_accept_junk is set, this
1881host is permitted to send any old junk (needed for some broken hosts).
1882Otherwise, helo_allow_chars can be used for rogue characters in general
1883(typically people want to let in underscores).
1884
1885Argument:
1886 s the data portion of the line (already past any white space)
1887
1888Returns: TRUE or FALSE
1889*/
1890
1891static BOOL
1892check_helo(uschar *s)
1893{
1894uschar *start = s;
1895uschar *end = s + Ustrlen(s);
88752192 1896BOOL yield = fl.helo_accept_junk;
059ec3d9
PH
1897
1898/* Discard any previous helo name */
1899
2d0dc929 1900if (sender_helo_name)
059ec3d9
PH
1901 {
1902 store_free(sender_helo_name);
1903 sender_helo_name = NULL;
1904 }
1905
1906/* Skip tests if junk is permitted. */
1907
1908if (!yield)
db57e575 1909
059ec3d9
PH
1910 /* Allow the new standard form for IPv6 address literals, namely,
1911 [IPv6:....], and because someone is bound to use it, allow an equivalent
1912 IPv4 form. Allow plain addresses as well. */
1913
1914 if (*s == '[')
1915 {
1916 if (end[-1] == ']')
1917 {
1918 end[-1] = 0;
1919 if (strncmpic(s, US"[IPv6:", 6) == 0)
1920 yield = (string_is_ip_address(s+6, NULL) == 6);
1921 else if (strncmpic(s, US"[IPv4:", 6) == 0)
1922 yield = (string_is_ip_address(s+6, NULL) == 4);
1923 else
1924 yield = (string_is_ip_address(s+1, NULL) != 0);
1925 end[-1] = ']';
1926 }
1927 }
1928
1929 /* Non-literals must be alpha, dot, hyphen, plus any non-valid chars
1930 that have been configured (usually underscore - sigh). */
1931
db57e575
JH
1932 else if (*s)
1933 for (yield = TRUE; *s; s++)
059ec3d9
PH
1934 if (!isalnum(*s) && *s != '.' && *s != '-' &&
1935 Ustrchr(helo_allow_chars, *s) == NULL)
1936 {
1937 yield = FALSE;
1938 break;
1939 }
059ec3d9
PH
1940
1941/* Save argument if OK */
1942
1943if (yield) sender_helo_name = string_copy_malloc(start);
1944return yield;
1945}
1946
1947
1948
1949
1950
1951/*************************************************
1952* Extract SMTP command option *
1953*************************************************/
1954
ca86f471 1955/* This function picks the next option setting off the end of smtp_cmd_data. It
059ec3d9
PH
1956is called for MAIL FROM and RCPT TO commands, to pick off the optional ESMTP
1957things that can appear there.
1958
1959Arguments:
1960 name point this at the name
1961 value point this at the data string
1962
1963Returns: TRUE if found an option
1964*/
1965
1966static BOOL
1967extract_option(uschar **name, uschar **value)
1968{
1969uschar *n;
ca86f471 1970uschar *v = smtp_cmd_data + Ustrlen(smtp_cmd_data) - 1;
059ec3d9
PH
1971while (isspace(*v)) v--;
1972v[1] = 0;
d7a2c833
JH
1973while (v > smtp_cmd_data && *v != '=' && !isspace(*v))
1974 {
1975 /* Take care to not stop at a space embedded in a quoted local-part */
1976
1977 if (*v == '"') do v--; while (*v != '"' && v > smtp_cmd_data+1);
1978 v--;
1979 }
059ec3d9
PH
1980
1981n = v;
fd98a5c6 1982if (*v == '=')
a2673768 1983 {
fd98a5c6
JH
1984 while(isalpha(n[-1])) n--;
1985 /* RFC says SP, but TAB seen in wild and other major MTAs accept it */
1986 if (!isspace(n[-1])) return FALSE;
1987 n[-1] = 0;
a2673768 1988 }
fd98a5c6 1989else
a2673768 1990 {
fd98a5c6
JH
1991 n++;
1992 if (v == smtp_cmd_data) return FALSE;
a2673768 1993 }
059ec3d9 1994*v++ = 0;
fd98a5c6 1995*name = n;
059ec3d9
PH
1996*value = v;
1997return TRUE;
1998}
1999
2000
2001
2002
2003
059ec3d9
PH
2004/*************************************************
2005* Reset for new message *
2006*************************************************/
2007
2008/* This function is called whenever the SMTP session is reset from
e04bfa34 2009within either of the setup functions; also from the daemon loop.
059ec3d9
PH
2010
2011Argument: the stacking pool storage reset point
2012Returns: nothing
2013*/
2014
e04bfa34 2015void
059ec3d9
PH
2016smtp_reset(void *reset_point)
2017{
059ec3d9
PH
2018recipients_list = NULL;
2019rcpt_count = rcpt_defer_count = rcpt_fail_count =
2020 raw_recipients_count = recipients_count = recipients_list_max = 0;
2e0c1448 2021message_linecount = 0;
059ec3d9 2022message_size = -1;
71fafd95 2023acl_added_headers = NULL;
e7568d51 2024acl_removed_headers = NULL;
8768d548 2025f.queue_only_policy = FALSE;
2679d413 2026rcpt_smtp_response = NULL;
88752192
JH
2027fl.rcpt_smtp_response_same = TRUE;
2028fl.rcpt_in_progress = FALSE;
8768d548 2029f.deliver_freeze = FALSE; /* Can be set by ACL */
6a3f1455 2030freeze_tell = freeze_tell_config; /* Can be set by ACL */
29aba418 2031fake_response = OK; /* Can be set by ACL */
6951ac6c 2032#ifdef WITH_CONTENT_SCAN
8768d548 2033f.no_mbox_unspool = FALSE; /* Can be set by ACL */
8523533c 2034#endif
8768d548
JH
2035f.submission_mode = FALSE; /* Can be set by ACL */
2036f.suppress_local_fixups = f.suppress_local_fixups_default; /* Can be set by ACL */
2037f.active_local_from_check = local_from_check; /* Can be set by ACL */
2038f.active_local_sender_retain = local_sender_retain; /* Can be set by ACL */
90341c71
JH
2039sending_ip_address = NULL;
2040return_path = sender_address = NULL;
2041sender_data = NULL; /* Can be set by ACL */
c679ee08
JH
2042deliver_localpart_parent = deliver_localpart_orig = NULL;
2043deliver_domain_parent = deliver_domain_orig = NULL;
90341c71 2044callout_address = NULL;
2fe1a124 2045submission_name = NULL; /* Can be set by ACL */
059ec3d9
PH
2046raw_sender = NULL; /* After SMTP rewrite, before qualifying */
2047sender_address_unrewritten = NULL; /* Set only after verify rewrite */
2048sender_verified_list = NULL; /* No senders verified */
2049memset(sender_address_cache, 0, sizeof(sender_address_cache));
2050memset(sender_domain_cache, 0, sizeof(sender_domain_cache));
6c1c3d1d 2051
059ec3d9 2052authenticated_sender = NULL;
8523533c
TK
2053#ifdef EXPERIMENTAL_BRIGHTMAIL
2054bmi_run = 0;
2055bmi_verdicts = NULL;
2056#endif
90341c71 2057dnslist_domain = dnslist_matched = NULL;
01067968
JH
2058#ifdef SUPPORT_SPF
2059spf_header_comment = spf_received = spf_result = spf_smtp_comment = NULL;
2060spf_result_guessed = FALSE;
2061#endif
80a47a2c 2062#ifndef DISABLE_DKIM
d342446f 2063dkim_cur_signer = dkim_signers =
b4757e36 2064dkim_signing_domain = dkim_signing_selector = dkim_signatures = NULL;
d342446f 2065dkim_cur_signer = dkim_signers = dkim_signing_domain = dkim_signing_selector = NULL;
8768d548 2066f.dkim_disable_verify = FALSE;
64b67b65 2067dkim_collect_input = 0;
d342446f
JH
2068dkim_verify_overall = dkim_verify_status = dkim_verify_reason = NULL;
2069dkim_key_length = 0;
2070dkim_verify_signers = US"$dkim_signers";
f7572e5a 2071#endif
b4757e36 2072#ifdef EXPERIMENTAL_DMARC
8768d548 2073f.dmarc_has_been_checked = f.dmarc_disable_verify = f.dmarc_enable_forensic = FALSE;
8aeef98a 2074dmarc_domain_policy = dmarc_status = dmarc_status_text =
6372d4c9 2075dmarc_used_domain = NULL;
f7572e5a 2076#endif
01067968
JH
2077#ifdef EXPERIMENTAL_ARC
2078arc_state = arc_state_reason = NULL;
b4757e36 2079#endif
aa368db3
JH
2080dsn_ret = 0;
2081dsn_envid = NULL;
90341c71 2082deliver_host = deliver_host_address = NULL; /* Can be set by ACL */
aa368db3
JH
2083#ifndef DISABLE_PRDR
2084prdr_requested = FALSE;
2085#endif
8c5d388a 2086#ifdef SUPPORT_I18N
d1a13eea
JH
2087message_smtputf8 = FALSE;
2088#endif
059ec3d9
PH
2089body_linecount = body_zerocount = 0;
2090
870f6ba8
TF
2091sender_rate = sender_rate_limit = sender_rate_period = NULL;
2092ratelimiters_mail = NULL; /* Updated by ratelimit ACL condition */
2093 /* Note that ratelimiters_conn persists across resets. */
2094
38a0a95f 2095/* Reset message ACL variables */
47ca6d6c 2096
38a0a95f 2097acl_var_m = NULL;
059ec3d9
PH
2098
2099/* The message body variables use malloc store. They may be set if this is
2100not the first message in an SMTP session and the previous message caused them
2101to be referenced in an ACL. */
2102
90341c71 2103if (message_body)
059ec3d9
PH
2104 {
2105 store_free(message_body);
2106 message_body = NULL;
2107 }
2108
90341c71 2109if (message_body_end)
059ec3d9
PH
2110 {
2111 store_free(message_body_end);
2112 message_body_end = NULL;
2113 }
2114
2115/* Warning log messages are also saved in malloc store. They are saved to avoid
2116repetition in the same message, but it seems right to repeat them for different
4e88a19f 2117messages. */
059ec3d9 2118
90341c71 2119while (acl_warn_logged)
059ec3d9
PH
2120 {
2121 string_item *this = acl_warn_logged;
2122 acl_warn_logged = acl_warn_logged->next;
2123 store_free(this);
2124 }
90341c71 2125store_reset(reset_point);
059ec3d9
PH
2126}
2127
2128
2129
2130
2131
2132/*************************************************
2133* Initialize for incoming batched SMTP message *
2134*************************************************/
2135
2136/* This function is called from smtp_setup_msg() in the case when
2137smtp_batched_input is true. This happens when -bS is used to pass a whole batch
2138of messages in one file with SMTP commands between them. All errors must be
2139reported by sending a message, and only MAIL FROM, RCPT TO, and DATA are
2140relevant. After an error on a sender, or an invalid recipient, the remainder
2141of the message is skipped. The value of received_protocol is already set.
2142
2143Argument: none
2144Returns: > 0 message successfully started (reached DATA)
2145 = 0 QUIT read or end of file reached
2146 < 0 should not occur
2147*/
2148
2149static int
2150smtp_setup_batch_msg(void)
2151{
2152int done = 0;
2153void *reset_point = store_get(0);
2154
2155/* Save the line count at the start of each transaction - single commands
2156like HELO and RSET count as whole transactions. */
2157
2158bsmtp_transaction_linecount = receive_linecount;
2159
2160if ((receive_feof)()) return 0; /* Treat EOF as QUIT */
2161
57cc2785 2162cancel_cutthrough_connection(TRUE, US"smtp_setup_batch_msg");
059ec3d9
PH
2163smtp_reset(reset_point); /* Reset for start of message */
2164
2165/* Deal with SMTP commands. This loop is exited by setting done to a POSITIVE
2166value. The values are 2 larger than the required yield of the function. */
2167
2168while (done <= 0)
2169 {
2170 uschar *errmess;
2171 uschar *recipient = NULL;
2172 int start, end, sender_domain, recipient_domain;
2173
bd8fbe36 2174 switch(smtp_read_command(FALSE, GETC_BUFFER_UNLIMITED))
059ec3d9
PH
2175 {
2176 /* The HELO/EHLO commands set sender_address_helo if they have
2177 valid data; otherwise they are ignored, except that they do
2178 a reset of the state. */
2179
2180 case HELO_CMD:
2181 case EHLO_CMD:
2182
db57e575
JH
2183 check_helo(smtp_cmd_data);
2184 /* Fall through */
059ec3d9
PH
2185
2186 case RSET_CMD:
db57e575
JH
2187 cancel_cutthrough_connection(TRUE, US"RSET received");
2188 smtp_reset(reset_point);
2189 bsmtp_transaction_linecount = receive_linecount;
2190 break;
059ec3d9
PH
2191
2192
2193 /* The MAIL FROM command requires an address as an operand. All we
2194 do here is to parse it for syntactic correctness. The form "<>" is
2195 a special case which converts into an empty string. The start/end
2196 pointers in the original are not used further for this address, as
2197 it is the canonical extracted address which is all that is kept. */
2198
2199 case MAIL_CMD:
db57e575
JH
2200 smtp_mailcmd_count++; /* Count for no-mail log */
2201 if (sender_address != NULL)
2202 /* The function moan_smtp_batch() does not return. */
2203 moan_smtp_batch(smtp_cmd_buffer, "503 Sender already given");
059ec3d9 2204
db57e575
JH
2205 if (smtp_cmd_data[0] == 0)
2206 /* The function moan_smtp_batch() does not return. */
2207 moan_smtp_batch(smtp_cmd_buffer, "501 MAIL FROM must have an address operand");
059ec3d9 2208
db57e575 2209 /* Reset to start of message */
059ec3d9 2210
db57e575
JH
2211 cancel_cutthrough_connection(TRUE, US"MAIL received");
2212 smtp_reset(reset_point);
059ec3d9 2213
db57e575 2214 /* Apply SMTP rewrite */
059ec3d9 2215
db57e575
JH
2216 raw_sender = ((rewrite_existflags & rewrite_smtp) != 0)?
2217 rewrite_one(smtp_cmd_data, rewrite_smtp|rewrite_smtp_sender, NULL, FALSE,
2218 US"", global_rewrite_rules) : smtp_cmd_data;
059ec3d9 2219
db57e575 2220 /* Extract the address; the TRUE flag allows <> as valid */
059ec3d9 2221
db57e575
JH
2222 raw_sender =
2223 parse_extract_address(raw_sender, &errmess, &start, &end, &sender_domain,
2224 TRUE);
059ec3d9 2225
db57e575
JH
2226 if (!raw_sender)
2227 /* The function moan_smtp_batch() does not return. */
2228 moan_smtp_batch(smtp_cmd_buffer, "501 %s", errmess);
059ec3d9 2229
db57e575 2230 sender_address = string_copy(raw_sender);
059ec3d9 2231
db57e575 2232 /* Qualify unqualified sender addresses if permitted to do so. */
059ec3d9 2233
db57e575
JH
2234 if ( !sender_domain
2235 && sender_address[0] != 0 && sender_address[0] != '@')
8768d548 2236 if (f.allow_unqualified_sender)
db57e575
JH
2237 {
2238 sender_address = rewrite_address_qualify(sender_address, FALSE);
2239 DEBUG(D_receive) debug_printf("unqualified address %s accepted "
2240 "and rewritten\n", raw_sender);
2241 }
2242 /* The function moan_smtp_batch() does not return. */
2243 else
2244 moan_smtp_batch(smtp_cmd_buffer, "501 sender address must contain "
2245 "a domain");
2246 break;
059ec3d9
PH
2247
2248
2249 /* The RCPT TO command requires an address as an operand. All we do
2250 here is to parse it for syntactic correctness. There may be any number
2251 of RCPT TO commands, specifying multiple senders. We build them all into
2252 a data structure that is in argc/argv format. The start/end values
2253 given by parse_extract_address are not used, as we keep only the
2254 extracted address. */
2255
2256 case RCPT_CMD:
db57e575
JH
2257 if (!sender_address)
2258 /* The function moan_smtp_batch() does not return. */
2259 moan_smtp_batch(smtp_cmd_buffer, "503 No sender yet given");
059ec3d9 2260
db57e575
JH
2261 if (smtp_cmd_data[0] == 0)
2262 /* The function moan_smtp_batch() does not return. */
2263 moan_smtp_batch(smtp_cmd_buffer,
2264 "501 RCPT TO must have an address operand");
059ec3d9 2265
db57e575 2266 /* Check maximum number allowed */
059ec3d9 2267
db57e575
JH
2268 if (recipients_max > 0 && recipients_count + 1 > recipients_max)
2269 /* The function moan_smtp_batch() does not return. */
2270 moan_smtp_batch(smtp_cmd_buffer, "%s too many recipients",
2271 recipients_max_reject? "552": "452");
059ec3d9 2272
db57e575
JH
2273 /* Apply SMTP rewrite, then extract address. Don't allow "<>" as a
2274 recipient address */
059ec3d9 2275
db57e575
JH
2276 recipient = rewrite_existflags & rewrite_smtp
2277 ? rewrite_one(smtp_cmd_data, rewrite_smtp, NULL, FALSE, US"",
2278 global_rewrite_rules)
2279 : smtp_cmd_data;
059ec3d9 2280
db57e575
JH
2281 recipient = parse_extract_address(recipient, &errmess, &start, &end,
2282 &recipient_domain, FALSE);
059ec3d9 2283
db57e575
JH
2284 if (!recipient)
2285 /* The function moan_smtp_batch() does not return. */
2286 moan_smtp_batch(smtp_cmd_buffer, "501 %s", errmess);
059ec3d9 2287
db57e575
JH
2288 /* If the recipient address is unqualified, qualify it if permitted. Then
2289 add it to the list of recipients. */
059ec3d9 2290
db57e575 2291 if (!recipient_domain)
8768d548 2292 if (f.allow_unqualified_recipient)
db57e575
JH
2293 {
2294 DEBUG(D_receive) debug_printf("unqualified address %s accepted\n",
2295 recipient);
2296 recipient = rewrite_address_qualify(recipient, TRUE);
2297 }
2298 /* The function moan_smtp_batch() does not return. */
2299 else
2300 moan_smtp_batch(smtp_cmd_buffer,
2301 "501 recipient address must contain a domain");
2302
2303 receive_add_recipient(recipient, -1);
2304 break;
059ec3d9
PH
2305
2306
2307 /* The DATA command is legal only if it follows successful MAIL FROM
2308 and RCPT TO commands. This function is complete when a valid DATA
2309 command is encountered. */
2310
2311 case DATA_CMD:
db57e575
JH
2312 if (!sender_address || recipients_count <= 0)
2313 /* The function moan_smtp_batch() does not return. */
2314 if (!sender_address)
2315 moan_smtp_batch(smtp_cmd_buffer,
2316 "503 MAIL FROM:<sender> command must precede DATA");
2317 else
2318 moan_smtp_batch(smtp_cmd_buffer,
2319 "503 RCPT TO:<recipient> must precede DATA");
059ec3d9 2320 else
db57e575
JH
2321 {
2322 done = 3; /* DATA successfully achieved */
2323 message_ended = END_NOTENDED; /* Indicate in middle of message */
2324 }
2325 break;
059ec3d9
PH
2326
2327
2328 /* The VRFY, EXPN, HELP, ETRN, and NOOP commands are ignored. */
2329
2330 case VRFY_CMD:
2331 case EXPN_CMD:
2332 case HELP_CMD:
2333 case NOOP_CMD:
2334 case ETRN_CMD:
db57e575
JH
2335 bsmtp_transaction_linecount = receive_linecount;
2336 break;
059ec3d9
PH
2337
2338
2339 case EOF_CMD:
2340 case QUIT_CMD:
db57e575
JH
2341 done = 2;
2342 break;
059ec3d9
PH
2343
2344
2345 case BADARG_CMD:
db57e575
JH
2346 /* The function moan_smtp_batch() does not return. */
2347 moan_smtp_batch(smtp_cmd_buffer, "501 Unexpected argument data");
2348 break;
059ec3d9
PH
2349
2350
2351 case BADCHAR_CMD:
db57e575
JH
2352 /* The function moan_smtp_batch() does not return. */
2353 moan_smtp_batch(smtp_cmd_buffer, "501 Unexpected NULL in SMTP command");
2354 break;
059ec3d9
PH
2355
2356
2357 default:
db57e575
JH
2358 /* The function moan_smtp_batch() does not return. */
2359 moan_smtp_batch(smtp_cmd_buffer, "500 Command unrecognized");
2360 break;
059ec3d9
PH
2361 }
2362 }
2363
2364return done - 2; /* Convert yield values */
2365}
2366
2367
2368
2369
13c7874e 2370#ifdef SUPPORT_TLS
cf0c6164
JH
2371static BOOL
2372smtp_log_tls_fail(uschar * errstr)
2373{
2374uschar * conn_info = smtp_get_connection_info();
2375
2376if (Ustrncmp(conn_info, US"SMTP ", 5) == 0) conn_info += 5;
2377/* I'd like to get separated H= here, but too hard for now */
2378
2379log_write(0, LOG_MAIN, "TLS error on %s %s", conn_info, errstr);
2380return FALSE;
2381}
13c7874e 2382#endif
cf0c6164
JH
2383
2384
a2673768
JH
2385
2386
2387#ifdef TCP_FASTOPEN
2388static void
2389tfo_in_check(void)
2390{
2391# ifdef TCP_INFO
2392struct tcp_info tinfo;
2393socklen_t len = sizeof(tinfo);
2394
2395if ( getsockopt(fileno(smtp_out), IPPROTO_TCP, TCP_INFO, &tinfo, &len) == 0
2396 && tinfo.tcpi_state == TCP_SYN_RECV
2397 )
2398 {
1ccd5f67 2399 DEBUG(D_receive) debug_printf("TCP_FASTOPEN mode connection (state TCP_SYN_RECV)\n");
8768d548 2400 f.tcp_in_fastopen = TRUE;
a2673768
JH
2401 }
2402# endif
2403}
2404#endif
2405
2406
059ec3d9
PH
2407/*************************************************
2408* Start an SMTP session *
2409*************************************************/
2410
2411/* This function is called at the start of an SMTP session. Thereafter,
2412smtp_setup_msg() is called to initiate each separate message. This
2413function does host-specific testing, and outputs the banner line.
2414
2415Arguments: none
2416Returns: FALSE if the session can not continue; something has
2417 gone wrong, or the connection to the host is blocked
2418*/
2419
2420BOOL
2421smtp_start_session(void)
2422{
acec9514 2423int esclen;
4e88a19f
PH
2424uschar *user_msg, *log_msg;
2425uschar *code, *esc;
acec9514
JH
2426uschar *p, *s;
2427gstring * ss;
059ec3d9 2428
0f1a8658 2429gettimeofday(&smtp_connection_start, NULL);
b4ed4da0
PH
2430for (smtp_ch_index = 0; smtp_ch_index < SMTP_HBUFF_SIZE; smtp_ch_index++)
2431 smtp_connection_had[smtp_ch_index] = SCH_NONE;
2432smtp_ch_index = 0;
2433
00f00ca5
PH
2434/* Default values for certain variables */
2435
88752192 2436fl.helo_seen = fl.esmtp = fl.helo_accept_junk = FALSE;
b4ed4da0 2437smtp_mailcmd_count = 0;
059ec3d9
PH
2438count_nonmail = TRUE_UNSET;
2439synprot_error_count = unknown_command_count = nonmail_command_count = 0;
2440smtp_delay_mail = smtp_rlm_base;
88752192 2441fl.auth_advertised = FALSE;
8768d548
JH
2442f.smtp_in_pipelining_advertised = f.smtp_in_pipelining_used = FALSE;
2443f.pipelining_enable = TRUE;
059ec3d9 2444sync_cmd_limit = NON_SYNC_CMD_NON_PIPELINING;
88752192 2445fl.smtp_exit_function_called = FALSE; /* For avoiding loop in not-quit exit */
059ec3d9 2446
33d73e3b
PH
2447/* If receiving by -bs from a trusted user, or testing with -bh, we allow
2448authentication settings from -oMaa to remain in force. */
2449
8768d548 2450if (!host_checking && !f.sender_host_notsocket)
c44ff8be 2451 sender_host_auth_pubname = sender_host_authenticated = NULL;
059ec3d9
PH
2452authenticated_by = NULL;
2453
2454#ifdef SUPPORT_TLS
817d9f57 2455tls_in.cipher = tls_in.peerdn = NULL;
9d1c15ef
JH
2456tls_in.ourcert = tls_in.peercert = NULL;
2457tls_in.sni = NULL;
44662487 2458tls_in.ocsp = OCSP_NOT_REQ;
88752192 2459fl.tls_advertised = FALSE;
8ac90765 2460# ifdef EXPERIMENTAL_REQUIRETLS
88752192 2461fl.requiretls_advertised = FALSE;
8ac90765 2462# endif
059ec3d9 2463#endif
88752192 2464fl.dsn_advertised = FALSE;
8c5d388a 2465#ifdef SUPPORT_I18N
88752192 2466fl.smtputf8_advertised = FALSE;
d1a13eea 2467#endif
059ec3d9
PH
2468
2469/* Reset ACL connection variables */
2470
38a0a95f 2471acl_var_c = NULL;
059ec3d9 2472
ca86f471 2473/* Allow for trailing 0 in the command and data buffers. */
3ee512ff 2474
bd8fbe36 2475if (!(smtp_cmd_buffer = US malloc(2*SMTP_CMD_BUFFER_SIZE + 2)))
059ec3d9
PH
2476 log_write(0, LOG_MAIN|LOG_PANIC_DIE,
2477 "malloc() failed for SMTP command buffer");
40c90bca 2478
2416c261 2479smtp_cmd_buffer[0] = 0;
bd8fbe36 2480smtp_data_buffer = smtp_cmd_buffer + SMTP_CMD_BUFFER_SIZE + 1;
059ec3d9
PH
2481
2482/* For batched input, the protocol setting can be overridden from the
2483command line by a trusted caller. */
2484
2485if (smtp_batched_input)
2486 {
40c90bca 2487 if (!received_protocol) received_protocol = US"local-bsmtp";
059ec3d9
PH
2488 }
2489
2490/* For non-batched SMTP input, the protocol setting is forced here. It will be
2491reset later if any of EHLO/AUTH/STARTTLS are received. */
2492
2493else
2494 received_protocol =
e524074d 2495 (sender_host_address ? protocols : protocols_local) [pnormal];
059ec3d9
PH
2496
2497/* Set up the buffer for inputting using direct read() calls, and arrange to
ecce6d9a
JH
2498call the local functions instead of the standard C ones. Place a NUL at the
2499end of the buffer to safety-stop C-string reads from it. */
059ec3d9 2500
5903c6ff 2501if (!(smtp_inbuffer = US malloc(IN_BUFFER_SIZE)))
059ec3d9 2502 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "malloc() failed for SMTP input buffer");
ecce6d9a 2503smtp_inbuffer[IN_BUFFER_SIZE-1] = '\0';
40c90bca 2504
059ec3d9 2505receive_getc = smtp_getc;
0d81dabc 2506receive_getbuf = smtp_getbuf;
584e96c6 2507receive_get_cache = smtp_get_cache;
059ec3d9
PH
2508receive_ungetc = smtp_ungetc;
2509receive_feof = smtp_feof;
2510receive_ferror = smtp_ferror;
58eb016e 2511receive_smtp_buffered = smtp_buffered;
059ec3d9
PH
2512smtp_inptr = smtp_inend = smtp_inbuffer;
2513smtp_had_eof = smtp_had_error = 0;
2514
2515/* Set up the message size limit; this may be host-specific */
2516
d45b1de8 2517thismessage_size_limit = expand_string_integer(message_size_limit, TRUE);
db57e575 2518if (expand_string_message)
059ec3d9
PH
2519 {
2520 if (thismessage_size_limit == -1)
2521 log_write(0, LOG_MAIN|LOG_PANIC, "unable to expand message_size_limit: "
2522 "%s", expand_string_message);
2523 else
2524 log_write(0, LOG_MAIN|LOG_PANIC, "invalid message_size_limit: "
2525 "%s", expand_string_message);
2526 smtp_closedown(US"Temporary local problem - please try later");
2527 return FALSE;
2528 }
2529
2530/* When a message is input locally via the -bs or -bS options, sender_host_
2531unknown is set unless -oMa was used to force an IP address, in which case it
2532is checked like a real remote connection. When -bs is used from inetd, this
2533flag is not set, causing the sending host to be checked. The code that deals
2534with IP source routing (if configured) is never required for -bs or -bS and
2535the flag sender_host_notsocket is used to suppress it.
2536
2537If smtp_accept_max and smtp_accept_reserve are set, keep some connections in
2538reserve for certain hosts and/or networks. */
2539
8768d548 2540if (!f.sender_host_unknown)
059ec3d9
PH
2541 {
2542 int rc;
2543 BOOL reserved_host = FALSE;
2544
2545 /* Look up IP options (source routing info) on the socket if this is not an
2546 -oMa "host", and if any are found, log them and drop the connection.
2547
2548 Linux (and others now, see below) is different to everyone else, so there
2549 has to be some conditional compilation here. Versions of Linux before 2.1.15
2550 used a structure whose name was "options". Somebody finally realized that
2551 this name was silly, and it got changed to "ip_options". I use the
2552 newer name here, but there is a fudge in the script that sets up os.h
2553 to define a macro in older Linux systems.
2554
2555 Sigh. Linux is a fast-moving target. Another generation of Linux uses
2556 glibc 2, which has chosen ip_opts for the structure name. This is now
2557 really a glibc thing rather than a Linux thing, so the condition name
2558 has been changed to reflect this. It is relevant also to GNU/Hurd.
2559
2560 Mac OS 10.x (Darwin) is like the later glibc versions, but without the
2561 setting of the __GLIBC__ macro, so we can't detect it automatically. There's
2562 a special macro defined in the os.h file.
2563
2564 Some DGUX versions on older hardware appear not to support IP options at
2565 all, so there is now a general macro which can be set to cut out this
2566 support altogether.
2567
2568 How to do this properly in IPv6 is not yet known. */
2569
e0574cb5 2570#if !HAVE_IPV6 && !defined(NO_IP_OPTIONS)
059ec3d9
PH
2571
2572 #ifdef GLIBC_IP_OPTIONS
2573 #if (!defined __GLIBC__) || (__GLIBC__ < 2)
2574 #define OPTSTYLE 1
2575 #else
2576 #define OPTSTYLE 2
2577 #endif
2578 #elif defined DARWIN_IP_OPTIONS
2579 #define OPTSTYLE 2
2580 #else
2581 #define OPTSTYLE 3
2582 #endif
2583
8768d548 2584 if (!host_checking && !f.sender_host_notsocket)
059ec3d9
PH
2585 {
2586 #if OPTSTYLE == 1
36a3b041 2587 EXIM_SOCKLEN_T optlen = sizeof(struct ip_options) + MAX_IPOPTLEN;
059ec3d9
PH
2588 struct ip_options *ipopt = store_get(optlen);
2589 #elif OPTSTYLE == 2
2590 struct ip_opts ipoptblock;
2591 struct ip_opts *ipopt = &ipoptblock;
36a3b041 2592 EXIM_SOCKLEN_T optlen = sizeof(ipoptblock);
059ec3d9
PH
2593 #else
2594 struct ipoption ipoptblock;
2595 struct ipoption *ipopt = &ipoptblock;
36a3b041 2596 EXIM_SOCKLEN_T optlen = sizeof(ipoptblock);
059ec3d9
PH
2597 #endif
2598
2599 /* Occasional genuine failures of getsockopt() have been seen - for
2600 example, "reset by peer". Therefore, just log and give up on this
2601 call, unless the error is ENOPROTOOPT. This error is given by systems
2602 that have the interfaces but not the mechanism - e.g. GNU/Hurd at the time
2603 of writing. So for that error, carry on - we just can't do an IP options
2604 check. */
2605
2606 DEBUG(D_receive) debug_printf("checking for IP options\n");
2607
5903c6ff 2608 if (getsockopt(fileno(smtp_out), IPPROTO_IP, IP_OPTIONS, US (ipopt),
059ec3d9
PH
2609 &optlen) < 0)
2610 {
2611 if (errno != ENOPROTOOPT)
2612 {
2613 log_write(0, LOG_MAIN, "getsockopt() failed from %s: %s",
2614 host_and_ident(FALSE), strerror(errno));
925ac8e4 2615 smtp_printf("451 SMTP service not available\r\n", FALSE);
059ec3d9
PH
2616 return FALSE;
2617 }
2618 }
2619
2620 /* Deal with any IP options that are set. On the systems I have looked at,
2621 the value of MAX_IPOPTLEN has been 40, meaning that there should never be
2622 more logging data than will fit in big_buffer. Nevertheless, after somebody
2623 questioned this code, I've added in some paranoid checking. */
2624
2625 else if (optlen > 0)
2626 {
2627 uschar *p = big_buffer;
2628 uschar *pend = big_buffer + big_buffer_size;
2629 uschar *opt, *adptr;
2630 int optcount;
2631 struct in_addr addr;
2632
2633 #if OPTSTYLE == 1
5903c6ff 2634 uschar *optstart = US (ipopt->__data);
059ec3d9 2635 #elif OPTSTYLE == 2
5903c6ff 2636 uschar *optstart = US (ipopt->ip_opts);
059ec3d9 2637 #else
5903c6ff 2638 uschar *optstart = US (ipopt->ipopt_list);
059ec3d9
PH
2639 #endif
2640
2641 DEBUG(D_receive) debug_printf("IP options exist\n");
2642
2643 Ustrcpy(p, "IP options on incoming call:");
2644 p += Ustrlen(p);
2645
2646 for (opt = optstart; opt != NULL &&
5903c6ff 2647 opt < US (ipopt) + optlen;)
059ec3d9
PH
2648 {
2649 switch (*opt)
2650 {
2651 case IPOPT_EOL:
2652 opt = NULL;
2653 break;
2654
2655 case IPOPT_NOP:
2656 opt++;
2657 break;
2658
2659 case IPOPT_SSRR:
2660 case IPOPT_LSRR:
2661 if (!string_format(p, pend-p, " %s [@%s",
2662 (*opt == IPOPT_SSRR)? "SSRR" : "LSRR",
2663 #if OPTSTYLE == 1
2664 inet_ntoa(*((struct in_addr *)(&(ipopt->faddr))))))
2665 #elif OPTSTYLE == 2
2666 inet_ntoa(ipopt->ip_dst)))
2667 #else
2668 inet_ntoa(ipopt->ipopt_dst)))
2669 #endif
2670 {
2671 opt = NULL;
2672 break;
2673 }
2674
2675 p += Ustrlen(p);
2676 optcount = (opt[1] - 3) / sizeof(struct in_addr);
2677 adptr = opt + 3;
2678 while (optcount-- > 0)
2679 {
2680 memcpy(&addr, adptr, sizeof(addr));
2681 if (!string_format(p, pend - p - 1, "%s%s",
2682 (optcount == 0)? ":" : "@", inet_ntoa(addr)))
2683 {
2684 opt = NULL;
2685 break;
2686 }
2687 p += Ustrlen(p);
2688 adptr += sizeof(struct in_addr);
2689 }
2690 *p++ = ']';
2691 opt += opt[1];
2692 break;
2693
2694 default:
2695 {
2696 int i;
2697 if (pend - p < 4 + 3*opt[1]) { opt = NULL; break; }
2698 Ustrcat(p, "[ ");
2699 p += 2;
2700 for (i = 0; i < opt[1]; i++)
5976eb99 2701 p += sprintf(CS p, "%2.2x ", opt[i]);
059ec3d9
PH
2702 *p++ = ']';
2703 }
2704 opt += opt[1];
2705 break;
2706 }
2707 }
2708
2709 *p = 0;
2710 log_write(0, LOG_MAIN, "%s", big_buffer);
2711
2712 /* Refuse any call with IP options. This is what tcpwrappers 7.5 does. */
2713
2714 log_write(0, LOG_MAIN|LOG_REJECT,
2715 "connection from %s refused (IP options)", host_and_ident(FALSE));
2716
925ac8e4 2717 smtp_printf("554 SMTP service not available\r\n", FALSE);
059ec3d9
PH
2718 return FALSE;
2719 }
2720
2721 /* Length of options = 0 => there are no options */
2722
2723 else DEBUG(D_receive) debug_printf("no IP options found\n");
2724 }
e0574cb5 2725#endif /* HAVE_IPV6 && !defined(NO_IP_OPTIONS) */
059ec3d9
PH
2726
2727 /* Set keep-alive in socket options. The option is on by default. This
2728 setting is an attempt to get rid of some hanging connections that stick in
2729 read() when the remote end (usually a dialup) goes away. */
2730
8768d548 2731 if (smtp_accept_keepalive && !f.sender_host_notsocket)
059ec3d9
PH
2732 ip_keepalive(fileno(smtp_out), sender_host_address, FALSE);
2733
2734 /* If the current host matches host_lookup, set the name by doing a
2735 reverse lookup. On failure, sender_host_name will be NULL and
2736 host_lookup_failed will be TRUE. This may or may not be serious - optional
2737 checks later. */
2738
2739 if (verify_check_host(&host_lookup) == OK)
2740 {
2741 (void)host_name_lookup();
2742 host_build_sender_fullhost();
2743 }
2744
2745 /* Delay this until we have the full name, if it is looked up. */
2746
2747 set_process_info("handling incoming connection from %s",
2748 host_and_ident(FALSE));
2749
1ad6489e
JH
2750 /* Expand smtp_receive_timeout, if needed */
2751
2752 if (smtp_receive_timeout_s)
2753 {
2754 uschar * exp;
2755 if ( !(exp = expand_string(smtp_receive_timeout_s))
2756 || !(*exp)
2757 || (smtp_receive_timeout = readconf_readtime(exp, 0, FALSE)) < 0
2758 )
2759 log_write(0, LOG_MAIN|LOG_PANIC,
2760 "bad value for smtp_receive_timeout: '%s'", exp ? exp : US"");
2761 }
2762
059ec3d9
PH
2763 /* Test for explicit connection rejection */
2764
2765 if (verify_check_host(&host_reject_connection) == OK)
2766 {
2767 log_write(L_connection_reject, LOG_MAIN|LOG_REJECT, "refused connection "
2768 "from %s (host_reject_connection)", host_and_ident(FALSE));
925ac8e4 2769 smtp_printf("554 SMTP service not available\r\n", FALSE);
059ec3d9
PH
2770 return FALSE;
2771 }
2772
afb3eaaf
PH
2773 /* Test with TCP Wrappers if so configured. There is a problem in that
2774 hosts_ctl() returns 0 (deny) under a number of system failure circumstances,
2775 such as disks dying. In these cases, it is desirable to reject with a 4xx
2776 error instead of a 5xx error. There isn't a "right" way to detect such
2777 problems. The following kludge is used: errno is zeroed before calling
2778 hosts_ctl(). If the result is "reject", a 5xx error is given only if the
2779 value of errno is 0 or ENOENT (which happens if /etc/hosts.{allow,deny} does
2780 not exist). */
059ec3d9 2781
1811cb4c 2782#ifdef USE_TCP_WRAPPERS
afb3eaaf 2783 errno = 0;
1811cb4c 2784 if (!(tcp_wrappers_name = expand_string(tcp_wrappers_daemon_name)))
5dc43717
JJ
2785 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "Expansion of \"%s\" "
2786 "(tcp_wrappers_name) failed: %s", string_printing(tcp_wrappers_name),
2787 expand_string_message);
1811cb4c 2788
5dc43717 2789 if (!hosts_ctl(tcp_wrappers_name,
1811cb4c
JH
2790 sender_host_name ? CS sender_host_name : STRING_UNKNOWN,
2791 sender_host_address ? CS sender_host_address : STRING_UNKNOWN,
2792 sender_ident ? CS sender_ident : STRING_UNKNOWN))
059ec3d9 2793 {
afb3eaaf
PH
2794 if (errno == 0 || errno == ENOENT)
2795 {
2796 HDEBUG(D_receive) debug_printf("tcp wrappers rejection\n");
2797 log_write(L_connection_reject,
2798 LOG_MAIN|LOG_REJECT, "refused connection from %s "
2799 "(tcp wrappers)", host_and_ident(FALSE));
925ac8e4 2800 smtp_printf("554 SMTP service not available\r\n", FALSE);
afb3eaaf
PH
2801 }
2802 else
2803 {
2804 int save_errno = errno;
2805 HDEBUG(D_receive) debug_printf("tcp wrappers rejected with unexpected "
2806 "errno value %d\n", save_errno);
2807 log_write(L_connection_reject,
2808 LOG_MAIN|LOG_REJECT, "temporarily refused connection from %s "
2809 "(tcp wrappers errno=%d)", host_and_ident(FALSE), save_errno);
925ac8e4 2810 smtp_printf("451 Temporary local problem - please try later\r\n", FALSE);
afb3eaaf 2811 }
059ec3d9
PH
2812 return FALSE;
2813 }
1811cb4c 2814#endif
059ec3d9 2815
b01dd148
PH
2816 /* Check for reserved slots. The value of smtp_accept_count has already been
2817 incremented to include this process. */
059ec3d9
PH
2818
2819 if (smtp_accept_max > 0 &&
b01dd148 2820 smtp_accept_count > smtp_accept_max - smtp_accept_reserve)
059ec3d9
PH
2821 {
2822 if ((rc = verify_check_host(&smtp_reserve_hosts)) != OK)
2823 {
2824 log_write(L_connection_reject,
2825 LOG_MAIN, "temporarily refused connection from %s: not in "
2826 "reserve list: connected=%d max=%d reserve=%d%s",
b01dd148 2827 host_and_ident(FALSE), smtp_accept_count - 1, smtp_accept_max,
059ec3d9
PH
2828 smtp_accept_reserve, (rc == DEFER)? " (lookup deferred)" : "");
2829 smtp_printf("421 %s: Too many concurrent SMTP connections; "
925ac8e4 2830 "please try again later\r\n", FALSE, smtp_active_hostname);
059ec3d9
PH
2831 return FALSE;
2832 }
2833 reserved_host = TRUE;
2834 }
2835
2836 /* If a load level above which only messages from reserved hosts are
2837 accepted is set, check the load. For incoming calls via the daemon, the
2838 check is done in the superior process if there are no reserved hosts, to
2839 save a fork. In all cases, the load average will already be available
2840 in a global variable at this point. */
2841
2842 if (smtp_load_reserve >= 0 &&
2843 load_average > smtp_load_reserve &&
2844 !reserved_host &&
2845 verify_check_host(&smtp_reserve_hosts) != OK)
2846 {
2847 log_write(L_connection_reject,
2848 LOG_MAIN, "temporarily refused connection from %s: not in "
2849 "reserve list and load average = %.2f", host_and_ident(FALSE),
2850 (double)load_average/1000.0);
925ac8e4 2851 smtp_printf("421 %s: Too much load; please try again later\r\n", FALSE,
059ec3d9
PH
2852 smtp_active_hostname);
2853 return FALSE;
2854 }
2855
2856 /* Determine whether unqualified senders or recipients are permitted
2857 for this host. Unfortunately, we have to do this every time, in order to
2858 set the flags so that they can be inspected when considering qualifying
2859 addresses in the headers. For a site that permits no qualification, this
2860 won't take long, however. */
2861
8768d548 2862 f.allow_unqualified_sender =
059ec3d9
PH
2863 verify_check_host(&sender_unqualified_hosts) == OK;
2864
8768d548 2865 f.allow_unqualified_recipient =
059ec3d9
PH
2866 verify_check_host(&recipient_unqualified_hosts) == OK;
2867
2868 /* Determine whether HELO/EHLO is required for this host. The requirement
2869 can be hard or soft. */
2870
88752192
JH
2871 fl.helo_required = verify_check_host(&helo_verify_hosts) == OK;
2872 if (!fl.helo_required)
2873 fl.helo_verify = verify_check_host(&helo_try_verify_hosts) == OK;
059ec3d9
PH
2874
2875 /* Determine whether this hosts is permitted to send syntactic junk
2876 after a HELO or EHLO command. */
2877
88752192 2878 fl.helo_accept_junk = verify_check_host(&helo_accept_junk_hosts) == OK;
059ec3d9
PH
2879 }
2880
2881/* For batch SMTP input we are now done. */
2882
2883if (smtp_batched_input) return TRUE;
2884
a3c86431
TL
2885/* If valid Proxy Protocol source is connecting, set up session.
2886 * Failure will not allow any SMTP function other than QUIT. */
1811cb4c
JH
2887
2888#ifdef SUPPORT_PROXY
a3c86431 2889proxy_session = FALSE;
8768d548 2890f.proxy_session_failed = FALSE;
a3c86431 2891if (check_proxy_protocol_host())
1811cb4c
JH
2892 setup_proxy_protocol_host();
2893#endif
2894
2895 /* Start up TLS if tls_on_connect is set. This is for supporting the legacy
2896 smtps port for use with older style SSL MTAs. */
2897
2898#ifdef SUPPORT_TLS
69d8eed7
JH
2899 if (tls_in.on_connect)
2900 {
2901 if (tls_server_start(tls_require_ciphers, &user_msg) != OK)
2902 return smtp_log_tls_fail(user_msg);
2903 cmd_list[CMD_LIST_TLS_AUTH].is_mail_cmd = TRUE;
2904 }
a3c86431
TL
2905#endif
2906
1811cb4c 2907/* Run the connect ACL if it exists */
059ec3d9 2908
4e88a19f 2909user_msg = NULL;
3cc3f762 2910if (acl_smtp_connect)
059ec3d9
PH
2911 {
2912 int rc;
3cc3f762
JH
2913 if ((rc = acl_check(ACL_WHERE_CONNECT, NULL, acl_smtp_connect, &user_msg,
2914 &log_msg)) != OK)
059ec3d9 2915 {
3cc3f762 2916 (void) smtp_handle_acl_fail(ACL_WHERE_CONNECT, rc, user_msg, log_msg);
059ec3d9
PH
2917 return FALSE;
2918 }
2919 }
2920
2921/* Output the initial message for a two-way SMTP connection. It may contain
2922newlines, which then cause a multi-line response to be given. */
2923
4e88a19f
PH
2924code = US"220"; /* Default status code */
2925esc = US""; /* Default extended status code */
2926esclen = 0; /* Length of esc */
2927
d4ff61d1 2928if (!user_msg)
4e88a19f 2929 {
d4ff61d1 2930 if (!(s = expand_string(smtp_banner)))
4e88a19f
PH
2931 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "Expansion of \"%s\" (smtp_banner) "
2932 "failed: %s", smtp_banner, expand_string_message);
2933 }
2934else
2935 {
2936 int codelen = 3;
2937 s = user_msg;
4f6ae5c3 2938 smtp_message_code(&code, &codelen, &s, NULL, TRUE);
d6a96edc 2939 if (codelen > 4)
4e88a19f
PH
2940 {
2941 esc = code + 4;
2942 esclen = codelen - 4;
2943 }
2944 }
059ec3d9
PH
2945
2946/* Remove any terminating newlines; might as well remove trailing space too */
2947
2948p = s + Ustrlen(s);
2949while (p > s && isspace(p[-1])) p--;
2950*p = 0;
2951
2952/* It seems that CC:Mail is braindead, and assumes that the greeting message
2953is all contained in a single IP packet. The original code wrote out the
2954greeting using several calls to fprint/fputc, and on busy servers this could
2955cause it to be split over more than one packet - which caused CC:Mail to fall
2956over when it got the second part of the greeting after sending its first
2957command. Sigh. To try to avoid this, build the complete greeting message
2958first, and output it in one fell swoop. This gives a better chance of it
2959ending up as a single packet. */
2960
acec9514 2961ss = string_get(256);
059ec3d9
PH
2962
2963p = s;
2964do /* At least once, in case we have an empty string */
2965 {
2966 int len;
2967 uschar *linebreak = Ustrchr(p, '\n');
acec9514 2968 ss = string_catn(ss, code, 3);
db57e575 2969 if (!linebreak)
059ec3d9
PH
2970 {
2971 len = Ustrlen(p);
acec9514 2972 ss = string_catn(ss, US" ", 1);
059ec3d9
PH
2973 }
2974 else
2975 {
2976 len = linebreak - p;
acec9514 2977 ss = string_catn(ss, US"-", 1);
059ec3d9 2978 }
acec9514
JH
2979 ss = string_catn(ss, esc, esclen);
2980 ss = string_catn(ss, p, len);
2981 ss = string_catn(ss, US"\r\n", 2);
059ec3d9 2982 p += len;
db57e575 2983 if (linebreak) p++;
059ec3d9 2984 }
db57e575 2985while (*p);
059ec3d9 2986
059ec3d9
PH
2987/* Before we write the banner, check that there is no input pending, unless
2988this synchronisation check is disabled. */
2989
a14e5636 2990if (!check_sync())
059ec3d9 2991 {
40525d07
JH
2992 unsigned n = smtp_inend - smtp_inptr;
2993 if (n > 32) n = 32;
2994
a14e5636
PH
2995 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP protocol "
2996 "synchronization error (input sent without waiting for greeting): "
2997 "rejected connection from %s input=\"%s\"", host_and_ident(TRUE),
40525d07 2998 string_printing(string_copyn(smtp_inptr, n)));
925ac8e4 2999 smtp_printf("554 SMTP synchronization error\r\n", FALSE);
a14e5636 3000 return FALSE;
059ec3d9
PH
3001 }
3002
3003/* Now output the banner */
3004
acec9514 3005smtp_printf("%s", FALSE, string_from_gstring(ss));
a2673768
JH
3006
3007/* Attempt to see if we sent the banner before the last ACK of the 3-way
3008handshake arrived. If so we must have managed a TFO. */
3009
3010#ifdef TCP_FASTOPEN
3011tfo_in_check();
3012#endif
3013
059ec3d9
PH
3014return TRUE;
3015}
3016
3017
3018
3019
3020
3021/*************************************************
3022* Handle SMTP syntax and protocol errors *
3023*************************************************/
3024
3025/* Write to the log for SMTP syntax errors in incoming commands, if configured
3026to do so. Then transmit the error response. The return value depends on the
3027number of syntax and protocol errors in this SMTP session.
3028
3029Arguments:
3030 type error type, given as a log flag bit
3031 code response code; <= 0 means don't send a response
3032 data data to reflect in the response (can be NULL)
3033 errmess the error message
3034
3035Returns: -1 limit of syntax/protocol errors NOT exceeded
3036 +1 limit of syntax/protocol errors IS exceeded
3037
3038These values fit in with the values of the "done" variable in the main
3039processing loop in smtp_setup_msg(). */
3040
3041static int
3042synprot_error(int type, int code, uschar *data, uschar *errmess)
3043{
3044int yield = -1;
3045
3046log_write(type, LOG_MAIN, "SMTP %s error in \"%s\" %s %s",
3047 (type == L_smtp_syntax_error)? "syntax" : "protocol",
3ee512ff 3048 string_printing(smtp_cmd_buffer), host_and_ident(TRUE), errmess);
059ec3d9
PH
3049
3050if (++synprot_error_count > smtp_max_synprot_errors)
3051 {
3052 yield = 1;
3053 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
3054 "syntax or protocol errors (last command was \"%s\")",
0ebc4d69 3055 host_and_ident(FALSE), string_printing(smtp_cmd_buffer));
059ec3d9
PH
3056 }
3057
3058if (code > 0)
3059 {
925ac8e4
JH
3060 smtp_printf("%d%c%s%s%s\r\n", FALSE, code, yield == 1 ? '-' : ' ',
3061 data ? data : US"", data ? US": " : US"", errmess);
059ec3d9 3062 if (yield == 1)
925ac8e4 3063 smtp_printf("%d Too many syntax or protocol errors\r\n", FALSE, code);
059ec3d9
PH
3064 }
3065
3066return yield;
3067}
3068
3069
3070
3071
3072/*************************************************
059ec3d9
PH
3073* Send SMTP response, possibly multiline *
3074*************************************************/
3075
3076/* There are, it seems, broken clients out there that cannot handle multiline
3077responses. If no_multiline_responses is TRUE (it can be set from an ACL), we
3078output nothing for non-final calls, and only the first line for anything else.
3079
3080Arguments:
a5bd321b 3081 code SMTP code, may involve extended status codes
d6a96edc 3082 codelen length of smtp code; if > 4 there's an ESC
059ec3d9
PH
3083 final FALSE if the last line isn't the final line
3084 msg message text, possibly containing newlines
3085
3086Returns: nothing
3087*/
3088
3089void
a5bd321b 3090smtp_respond(uschar* code, int codelen, BOOL final, uschar *msg)
059ec3d9 3091{
a5bd321b
PH
3092int esclen = 0;
3093uschar *esc = US"";
3094
8768d548 3095if (!final && f.no_multiline_responses) return;
059ec3d9 3096
d6a96edc 3097if (codelen > 4)
a5bd321b
PH
3098 {
3099 esc = code + 4;
3100 esclen = codelen - 4;
3101 }
3102
2679d413
PH
3103/* If this is the first output for a (non-batch) RCPT command, see if all RCPTs
3104have had the same. Note: this code is also present in smtp_printf(). It would
3105be tidier to have it only in one place, but when it was added, it was easier to
3106do it that way, so as not to have to mess with the code for the RCPT command,
3107which sometimes uses smtp_printf() and sometimes smtp_respond(). */
3108
88752192 3109if (fl.rcpt_in_progress)
2679d413
PH
3110 {
3111 if (rcpt_smtp_response == NULL)
3112 rcpt_smtp_response = string_copy(msg);
88752192 3113 else if (fl.rcpt_smtp_response_same &&
2679d413 3114 Ustrcmp(rcpt_smtp_response, msg) != 0)
88752192
JH
3115 fl.rcpt_smtp_response_same = FALSE;
3116 fl.rcpt_in_progress = FALSE;
2679d413
PH
3117 }
3118
e5de01f0 3119/* Now output the message, splitting it up into multiple lines if necessary.
925ac8e4
JH
3120We only handle pipelining these responses as far as nonfinal/final groups,
3121not the whole MAIL/RCPT/DATA response set. */
2679d413 3122
059ec3d9
PH
3123for (;;)
3124 {
3125 uschar *nl = Ustrchr(msg, '\n');
3126 if (nl == NULL)
3127 {
925ac8e4 3128 smtp_printf("%.3s%c%.*s%s\r\n", !final, code, final ? ' ':'-', esclen, esc, msg);
059ec3d9
PH
3129 return;
3130 }
8768d548 3131 else if (nl[1] == 0 || f.no_multiline_responses)
059ec3d9 3132 {
925ac8e4 3133 smtp_printf("%.3s%c%.*s%.*s\r\n", !final, code, final ? ' ':'-', esclen, esc,
a5bd321b 3134 (int)(nl - msg), msg);
059ec3d9
PH
3135 return;
3136 }
3137 else
3138 {
925ac8e4 3139 smtp_printf("%.3s-%.*s%.*s\r\n", TRUE, code, esclen, esc, (int)(nl - msg), msg);
059ec3d9
PH
3140 msg = nl + 1;
3141 while (isspace(*msg)) msg++;
3142 }
3143 }
3144}
3145
3146
3147
3148
3149/*************************************************
4e88a19f
PH
3150* Parse user SMTP message *
3151*************************************************/
3152
3153/* This function allows for user messages overriding the response code details
3154by providing a suitable response code string at the start of the message
3155user_msg. Check the message for starting with a response code and optionally an
3156extended status code. If found, check that the first digit is valid, and if so,
3157change the code pointer and length to use the replacement. An invalid code
3158causes a panic log; in this case, if the log messages is the same as the user
3159message, we must also adjust the value of the log message to show the code that
3160is actually going to be used (the original one).
3161
3162This function is global because it is called from receive.c as well as within
3163this module.
3164
d6a96edc
PH
3165Note that the code length returned includes the terminating whitespace
3166character, which is always included in the regex match.
3167
4e88a19f
PH
3168Arguments:
3169 code SMTP code, may involve extended status codes
d6a96edc 3170 codelen length of smtp code; if > 4 there's an ESC
4e88a19f
PH
3171 msg message text
3172 log_msg optional log message, to be adjusted with the new SMTP code
4f6ae5c3 3173 check_valid if true, verify the response code
4e88a19f
PH
3174
3175Returns: nothing
3176*/
3177
3178void
4f6ae5c3
JH
3179smtp_message_code(uschar **code, int *codelen, uschar **msg, uschar **log_msg,
3180 BOOL check_valid)
4e88a19f
PH
3181{
3182int n;
3183int ovector[3];
3184
4f6ae5c3 3185if (!msg || !*msg) return;
4e88a19f 3186
4f6ae5c3
JH
3187if ((n = pcre_exec(regex_smtp_code, NULL, CS *msg, Ustrlen(*msg), 0,
3188 PCRE_EOPT, ovector, sizeof(ovector)/sizeof(int))) < 0) return;
4e88a19f 3189
4f6ae5c3 3190if (check_valid && (*msg)[0] != (*code)[0])
4e88a19f
PH
3191 {
3192 log_write(0, LOG_MAIN|LOG_PANIC, "configured error code starts with "
3193 "incorrect digit (expected %c) in \"%s\"", (*code)[0], *msg);
3194 if (log_msg != NULL && *log_msg == *msg)
3195 *log_msg = string_sprintf("%s %s", *code, *log_msg + ovector[1]);
3196 }
3197else
3198 {
3199 *code = *msg;
3200 *codelen = ovector[1]; /* Includes final space */
3201 }
3202*msg += ovector[1]; /* Chop the code off the message */
3203return;
3204}
3205
3206
3207
3208
3209/*************************************************
059ec3d9
PH
3210* Handle an ACL failure *
3211*************************************************/
3212
3213/* This function is called when acl_check() fails. As well as calls from within
3214this module, it is called from receive.c for an ACL after DATA. It sorts out
5b6f7658 3215logging the incident, and sends the error response. A message containing
059ec3d9
PH
3216newlines is turned into a multiline SMTP response, but for logging, only the
3217first line is used.
3218
a5bd321b
PH
3219There's a table of default permanent failure response codes to use in
3220globals.c, along with the table of names. VFRY is special. Despite RFC1123 it
3221defaults disabled in Exim. However, discussion in connection with RFC 821bis
3222(aka RFC 2821) has concluded that the response should be 252 in the disabled
3223state, because there are broken clients that try VRFY before RCPT. A 5xx
3224response should be given only when the address is positively known to be
4f6ae5c3
JH
3225undeliverable. Sigh. We return 252 if there is no VRFY ACL or it provides
3226no explicit code, but if there is one we let it know best.
3227Also, for ETRN, 458 is given on refusal, and for AUTH, 503.
a5bd321b
PH
3228
3229From Exim 4.63, it is possible to override the response code details by
3230providing a suitable response code string at the start of the message provided
3231in user_msg. The code's first digit is checked for validity.
059ec3d9
PH
3232
3233Arguments:
4f6ae5c3
JH
3234 where where the ACL was called from
3235 rc the failure code
3236 user_msg a message that can be included in an SMTP response
3237 log_msg a message for logging
059ec3d9
PH
3238
3239Returns: 0 in most cases
3240 2 if the failure code was FAIL_DROP, in which case the
3241 SMTP connection should be dropped (this value fits with the
3242 "done" variable in smtp_setup_msg() below)
3243*/
3244
3245int
3246smtp_handle_acl_fail(int where, int rc, uschar *user_msg, uschar *log_msg)
3247{
059ec3d9 3248BOOL drop = rc == FAIL_DROP;
a5bd321b 3249int codelen = 3;
a5bd321b 3250uschar *smtp_code;
059ec3d9
PH
3251uschar *lognl;
3252uschar *sender_info = US"";
64ffc24f 3253uschar *what =
8523533c 3254#ifdef WITH_CONTENT_SCAN
3cc3f762 3255 where == ACL_WHERE_MIME ? US"during MIME ACL checks" :
8e669ac1 3256#endif
3cc3f762
JH
3257 where == ACL_WHERE_PREDATA ? US"DATA" :
3258 where == ACL_WHERE_DATA ? US"after DATA" :
8ccd00b1 3259#ifndef DISABLE_PRDR
3cc3f762 3260 where == ACL_WHERE_PRDR ? US"after DATA PRDR" :
fd98a5c6 3261#endif
3cc3f762
JH
3262 smtp_cmd_data ?
3263 string_sprintf("%s %s", acl_wherenames[where], smtp_cmd_data) :
3264 string_sprintf("%s in \"connect\" ACL", acl_wherenames[where]);
059ec3d9
PH
3265
3266if (drop) rc = FAIL;
3267
4e88a19f 3268/* Set the default SMTP code, and allow a user message to change it. */
a5bd321b 3269
4f6ae5c3
JH
3270smtp_code = rc == FAIL ? acl_wherecodes[where] : US"451";
3271smtp_message_code(&smtp_code, &codelen, &user_msg, &log_msg,
3272 where != ACL_WHERE_VRFY);
a5bd321b 3273
059ec3d9
PH
3274/* We used to have sender_address here; however, there was a bug that was not
3275updating sender_address after a rewrite during a verify. When this bug was
3276fixed, sender_address at this point became the rewritten address. I'm not sure
3277this is what should be logged, so I've changed to logging the unrewritten
3278address to retain backward compatibility. */
3279
8523533c 3280#ifndef WITH_CONTENT_SCAN
059ec3d9 3281if (where == ACL_WHERE_RCPT || where == ACL_WHERE_DATA)
8523533c
TK
3282#else
3283if (where == ACL_WHERE_RCPT || where == ACL_WHERE_DATA || where == ACL_WHERE_MIME)
3284#endif
059ec3d9 3285 {
b98bb9ac
PP
3286 sender_info = string_sprintf("F=<%s>%s%s%s%s ",
3287 sender_address_unrewritten ? sender_address_unrewritten : sender_address,
3288 sender_host_authenticated ? US" A=" : US"",
3289 sender_host_authenticated ? sender_host_authenticated : US"",
3290 sender_host_authenticated && authenticated_id ? US":" : US"",
3291 sender_host_authenticated && authenticated_id ? authenticated_id : US""
3292 );
059ec3d9
PH
3293 }
3294
3295/* If there's been a sender verification failure with a specific message, and
3296we have not sent a response about it yet, do so now, as a preliminary line for
278c6e6c
PH
3297failures, but not defers. However, always log it for defer, and log it for fail
3298unless the sender_verify_fail log selector has been turned off. */
059ec3d9 3299
02b41d71 3300if (sender_verified_failed &&
059ec3d9
PH
3301 !testflag(sender_verified_failed, af_sverify_told))
3302 {
88752192
JH
3303 BOOL save_rcpt_in_progress = fl.rcpt_in_progress;
3304 fl.rcpt_in_progress = FALSE; /* So as not to treat these as the error */
2679d413 3305
059ec3d9
PH
3306 setflag(sender_verified_failed, af_sverify_told);
3307
6c6d6e48 3308 if (rc != FAIL || LOGGING(sender_verify_fail))
278c6e6c
PH
3309 log_write(0, LOG_MAIN|LOG_REJECT, "%s sender verify %s for <%s>%s",
3310 host_and_ident(TRUE),
3311 ((sender_verified_failed->special_action & 255) == DEFER)? "defer":"fail",
3312 sender_verified_failed->address,
3313 (sender_verified_failed->message == NULL)? US"" :
3314 string_sprintf(": %s", sender_verified_failed->message));
059ec3d9 3315
02b41d71 3316 if (rc == FAIL && sender_verified_failed->user_message)
a5bd321b 3317 smtp_respond(smtp_code, codelen, FALSE, string_sprintf(
059ec3d9
PH
3318 testflag(sender_verified_failed, af_verify_pmfail)?
3319 "Postmaster verification failed while checking <%s>\n%s\n"
3320 "Several RFCs state that you are required to have a postmaster\n"
3321 "mailbox for each mail domain. This host does not accept mail\n"
3322 "from domains whose servers reject the postmaster address."
3323 :
3324 testflag(sender_verified_failed, af_verify_nsfail)?
3325 "Callback setup failed while verifying <%s>\n%s\n"
3326 "The initial connection, or a HELO or MAIL FROM:<> command was\n"
3327 "rejected. Refusing MAIL FROM:<> does not help fight spam, disregards\n"
3328 "RFC requirements, and stops you from receiving standard bounce\n"
3329 "messages. This host does not accept mail from domains whose servers\n"
3330 "refuse bounces."
3331 :
3332 "Verification failed for <%s>\n%s",
3333 sender_verified_failed->address,
3334 sender_verified_failed->user_message));
2679d413 3335
88752192 3336 fl.rcpt_in_progress = save_rcpt_in_progress;
059ec3d9
PH
3337 }
3338
3339/* Sort out text for logging */
3340
3cc3f762
JH
3341log_msg = log_msg ? string_sprintf(": %s", log_msg) : US"";
3342if ((lognl = Ustrchr(log_msg, '\n'))) *lognl = 0;
059ec3d9
PH
3343
3344/* Send permanent failure response to the command, but the code used isn't
3345always a 5xx one - see comments at the start of this function. If the original
3346rc was FAIL_DROP we drop the connection and yield 2. */
3347
ff5929e3
JH
3348if (rc == FAIL)
3349 smtp_respond(smtp_code, codelen, TRUE,
3350 user_msg ? user_msg : US"Administrative prohibition");
059ec3d9
PH
3351
3352/* Send temporary failure response to the command. Don't give any details,
3353unless acl_temp_details is set. This is TRUE for a callout defer, a "defer"
3354verb, and for a header verify when smtp_return_error_details is set.
3355
3356This conditional logic is all somewhat of a mess because of the odd
3357interactions between temp_details and return_error_details. One day it should
3358be re-implemented in a tidier fashion. */
3359
3360else
8768d548 3361 if (f.acl_temp_details && user_msg)
059ec3d9 3362 {
ff5929e3
JH
3363 if ( smtp_return_error_details
3364 && sender_verified_failed
3365 && sender_verified_failed->message
3366 )
a5bd321b 3367 smtp_respond(smtp_code, codelen, FALSE, sender_verified_failed->message);
ff5929e3 3368
a5bd321b 3369 smtp_respond(smtp_code, codelen, TRUE, user_msg);
059ec3d9
PH
3370 }
3371 else
a5bd321b
PH
3372 smtp_respond(smtp_code, codelen, TRUE,
3373 US"Temporary local problem - please try later");
059ec3d9 3374
6ea85e9a
PH
3375/* Log the incident to the logs that are specified by log_reject_target
3376(default main, reject). This can be empty to suppress logging of rejections. If
3377the connection is not forcibly to be dropped, return 0. Otherwise, log why it
3378is closing if required and return 2. */
059ec3d9 3379
6ea85e9a 3380if (log_reject_target != 0)
887291d2 3381 {
e45a1c37 3382#ifdef SUPPORT_TLS
acec9514
JH
3383 gstring * g = s_tlslog(NULL);
3384 uschar * tls = string_from_gstring(g);
fc16abb4 3385 if (!tls) tls = US"";
e45a1c37 3386#else
fc16abb4 3387 uschar * tls = US"";
e45a1c37 3388#endif
3cc3f762
JH
3389 log_write(where == ACL_WHERE_CONNECT ? L_connection_reject : 0,
3390 log_reject_target, "%s%s%s %s%srejected %s%s",
fc16abb4
JH
3391 LOGGING(dnssec) && sender_host_dnssec ? US" DS" : US"",
3392 host_and_ident(TRUE),
3393 tls,
3394 sender_info,
3395 rc == FAIL ? US"" : US"temporarily ",
3396 what, log_msg);
887291d2 3397 }
059ec3d9
PH
3398
3399if (!drop) return 0;
3400
3401log_write(L_smtp_connection, LOG_MAIN, "%s closed by DROP in ACL",
3402 smtp_get_connection_info());
8f128379
PH
3403
3404/* Run the not-quit ACL, but without any custom messages. This should not be a
3405problem, because we get here only if some other ACL has issued "drop", and
3406in that case, *its* custom messages will have been used above. */
3407
3408smtp_notquit_exit(US"acl-drop", NULL, NULL);
059ec3d9
PH
3409return 2;
3410}
3411
3412
3413
3414
3415/*************************************************
8f128379
PH
3416* Handle SMTP exit when QUIT is not given *
3417*************************************************/
3418
3419/* This function provides a logging/statistics hook for when an SMTP connection
3420is dropped on the floor or the other end goes away. It's a global function
3421because it's called from receive.c as well as this module. As well as running
3422the NOTQUIT ACL, if there is one, this function also outputs a final SMTP
3423response, either with a custom message from the ACL, or using a default. There
3424is one case, however, when no message is output - after "drop". In that case,
3425the ACL that obeyed "drop" has already supplied the custom message, and NULL is
3426passed to this function.
3427
3428In case things go wrong while processing this function, causing an error that
4c04137d 3429may re-enter this function, there is a recursion check.
8f128379
PH
3430
3431Arguments:
3432 reason What $smtp_notquit_reason will be set to in the ACL;
3433 if NULL, the ACL is not run
3434 code The error code to return as part of the response
3435 defaultrespond The default message if there's no user_msg
3436
3437Returns: Nothing
3438*/
3439
3440void
3441smtp_notquit_exit(uschar *reason, uschar *code, uschar *defaultrespond, ...)
3442{
3443int rc;
3444uschar *user_msg = NULL;
3445uschar *log_msg = NULL;
3446
3447/* Check for recursive acll */
3448
88752192 3449if (fl.smtp_exit_function_called)
8f128379
PH
3450 {
3451 log_write(0, LOG_PANIC, "smtp_notquit_exit() called more than once (%s)",
3452 reason);
3453 return;
3454 }
88752192 3455fl.smtp_exit_function_called = TRUE;
8f128379
PH
3456
3457/* Call the not-QUIT ACL, if there is one, unless no reason is given. */
3458
eea0defe 3459if (acl_smtp_notquit && reason)
8f128379
PH
3460 {
3461 smtp_notquit_reason = reason;
eea0defe
JB
3462 if ((rc = acl_check(ACL_WHERE_NOTQUIT, NULL, acl_smtp_notquit, &user_msg,
3463 &log_msg)) == ERROR)
8f128379
PH
3464 log_write(0, LOG_MAIN|LOG_PANIC, "ACL for not-QUIT returned ERROR: %s",
3465 log_msg);
3466 }
3467
58c09a7f
JH
3468/* If the connection was dropped, we certainly are no longer talking TLS */
3469tls_in.active.sock = -1;
3470
8f128379
PH
3471/* Write an SMTP response if we are expected to give one. As the default
3472responses are all internal, they should always fit in the buffer, but code a
3473warning, just in case. Note that string_vformat() still leaves a complete
3474string, even if it is incomplete. */
3475
eea0defe 3476if (code && defaultrespond)
8f128379 3477 {
eea0defe
JB
3478 if (user_msg)
3479 smtp_respond(code, 3, TRUE, user_msg);
3480 else
8f128379
PH
3481 {
3482 uschar buffer[128];
3483 va_list ap;
3484 va_start(ap, defaultrespond);
3485 if (!string_vformat(buffer, sizeof(buffer), CS defaultrespond, ap))
3486 log_write(0, LOG_MAIN|LOG_PANIC, "string too large in smtp_notquit_exit()");
925ac8e4 3487 smtp_printf("%s %s\r\n", FALSE, code, buffer);
8f128379
PH
3488 va_end(ap);
3489 }
8f128379
PH
3490 mac_smtp_fflush();
3491 }
3492}
3493
3494
3495
3496
3497/*************************************************
d7b47fd0
PH
3498* Verify HELO argument *
3499*************************************************/
3500
3501/* This function is called if helo_verify_hosts or helo_try_verify_hosts is
3502matched. It is also called from ACL processing if verify = helo is used and
3503verification was not previously tried (i.e. helo_try_verify_hosts was not
3504matched). The result of its processing is to set helo_verified and
3505helo_verify_failed. These variables should both be FALSE for this function to